By X. Yasmin. Air Force Institute of Technology. 2019.
Continued 159 159 Signs of opioid overdose z Unconscious (does not respond verbally or by opening eyes when spoken to loudly and shaken gently) z Constricted pupils z Hypoventilation (respiration rate too slow or tidal volume too low) z Cool moist skin 160 160 Opioid overdose: Steps to take (1) If an opioid overdose is suspected: z Oxygen cheap isoptin 120mg without a prescription, if available z Naloxone – 0 order isoptin cheap online. Dose may be repeated after 2 minutes if no response generic isoptin 120mg line, to a maximum of 10mg z Call ambulance z Advise reception of emergency and location 161 161 Opioid overdose: Steps to take (2) Assess the client: If responsive z Airway – open and clear z Breathing – respiratory rate and volume z Circulation – carotid pulse 162 162 Opioid overdose: Steps to take (3) If unresponsive, respiratory arrest, or hypoventilating z Call ambulance z Place in lateral coma position if breathing spontaneously z Bag and mask, ventilate with oxygen for hypoventilation z Naloxone 0. Projects of this type are underway in San Francisco and Chicago, and pilot projects started in Scotland in 2006. Therefore, adjunctive medicines often are necessary to treat insomnia, muscle pain, bone pain, and headache. Buprenorphine can be successfully used for withdrawal management (gradually tapered) and then naltrexone started after 3-5 days for maintenance. This withdrawal procedure might be much more convenient than the use of clonidine, which has a significant effect on blood pressure. This weekly dose should be divided up according to one of the following schedules: z 50 mg (one tablet) every day; or z 50 mg a day during the week and 100 mg (two tablets) on Saturday; or z 100 mg every other day; or z 100 mg on Mondays and Wednesdays, and 150 mg (three tablets) on Fridays; or z 150 mg every three days 179 179 Naltrexone for opiate relapse prevention (1) Side effects Precautions z Acute opioid withdrawal z If naltrexone ceased and precipitated opioid use reinstated, (e. Therefore, a favourable treatment outcome requires a positive therapeutic relationship, careful monitoring of medication compliance, and effective behavioural interventions. A llergy • A llergic reaction is an exaggerated or inappropriate im m une reaction and causes dam age to the host. Th e sensitiz ationprocess begins wh enm acroph ages degrade th e allergenand display th e resulting fragm ents to T lym ph ocytes. F ollowing th is,ina process involving secretion ofinterleukin4 by T cells,B lym ph ocytes m ature into plasm a cells able to secrete allergen-specificm olecules knownas IgE antibodies. O nfurth erexposure betweenth e allergenand th e im m une system ,allergenm olecules bind to IgE antibodies onm astcells. W h enone such m olecule connects with two IgE m olecules onth e cell surface,itdraws togeth erth e attach ed IgE receptors,th ereby directly orindirectly activating various enz ym es inth e cellm em brane. C ascades ofch em icals and enz ym es are released from intracellular granules Th ese cascades also appearto prom ote th e synth esis and release ofch em icals knownas cytokines. C h em icals em itted by activated m astcells and th eirneigh bours intissue m ay induce basoph ils, eosinoph ils,and oth ercells flowing th rough blood vessels to m igrate into th attissue. Th e ch em icals facilitate m igrationby prom oting th e expressionand activity ofadh esionm olecules onth e circulating cells and onvascularendoth elialcells. Th e circulating cells th enattach to th e endoth elialcells, rollalong th em ,and eventually,cross betweenth em into th e surrounding m atrix. Th ese recruited cells secrete ch em icals ofth eirown,wh ich cansustainim m une activity and dam age tissue. N eonatal & infant im m une system s S erialinfections Im m une response Th 1 Th 2 Th 2 A ge B alanced Th 1/Th 2 Th e intrauterine environm entis powerfully Th 2 – at~2yr th is im prints Th 2 dom inance uponth e neonate D elayed m aturation of Th1 capacity F ew serialinfections – h ygiene,sm allfam ily siz e etc Im m une response Th 1 Th 2 A ge U nbalanced Th 1/Th 2 Th 2 dom inance at~2yr L ongerperiod oftim e inwh ich to m ake and establish Th 2 responses to environm entalantigens (i. This m ay have resulted in m ore w idespread clinical expression of atopic disease" Itcanbe interpreted interm s ofa failure to m icrobially m odulate default Th 2 responses inch ildh ood Fam ily history for asthm a and cum ulative incidence of allergic diseases in offspring. G enetics Clim ate change im pact on the ecosystem of pollen‐producing plants Environm ent Cutaneous exposure to a food allergen, especially to inflam ed skin,m ay be a sensitizing route. W ith a concom itant lack of oral exposure to induce tolerance, the effect could N utrition be prom oting food allergy The com plex interplay betw een hostand environm entalfactors leading to allergic diseases A llergic R hinitis • R hinitis ‐ definition: Inflam m ation of the m em branes lining the nose • Characterized by nasal congestion, rhinorrhea, sneezing, itching of the nose, and/ or post nasal drainage, dry cough, ocular sym ptom s • A llergic rhinitis ‐ definition: Rhinitis that is caused by an IgE‐m ediated reaction to an aeroallergen. C opyrigh tElsevier2002 Food A llergy A dverse food reaction ‐ any aberrant reaction after ingestion of a food or food additive • Toxic reactions — due to toxin (bacterial, other) present in a food • N ontoxic reactions ‐ depends on individual susceptibilities • Im m une ‐ allergy or hypersensitivity (Type I) • N onim m une – intolerances: D ue to pharm acological properties of the food (caffeine or tyram ine), U nique susceptibility of the host (lactase deficiency), E. The English version serves two purposes: as a learning aid for international students and to encourage German-speaking students to familiarize themselves with medical English; the lectures are delivered in German. The translation from the original German version is my own; I am afraid it will occasionally sound appalling to native English speakers, but it should at least be intelligible. Over the course of evolution, this has led to the development of highly sophisticated defense systems in multicellular organisms. To maintain the integrity of our organism, it is essential to distinguish between biological structures that have to be fought off –ideally, everything that poses a danger to our organism—and structures that must not be attacked, e. This problem is not at all trivial, as dangerous attackers from the worlds of viruses, bacteria and parasites consist of largely the same molecules as the human body. Early in evolution, simple multicellular organisms developed a defense system activated by sensing typical molecular patterns associated with pathogens or distressed cells. In the best case, it nips an incipient infection in the bud; in the worst case, it keeps an infection in check for a few days. We are all absolutely dependent on this "old" system: infectious agents propagate so fast that we would be dead long before the second, evolutionarily younger system had a chance to kick in. Our most efficient defense mechanisms mount a custom-made counter-attack against the specific infectious agent invading our organism. Bespoke work takes time, meaning the system is simply not ready for use during the first days of an infection. This is because our immune system is able to learn what constitutes "self"; everything else is viewed with suspicion. As additional criteria to assess the level of danger, activation of the first, innate system is taken into account. While these molecules in fact cause inflammation, their ultimate goal is of course not inflammation, but defense. The drawback: if we would like to inhibit unwanted inflammation, we are usually able to alleviate it, but not to suppress it completely. It has a basic recognition function for many bacteria, can alert and recruit phagocytes, enhance visibility of bacteria to phagocytes and sometimes even lyse bacteria. The third pathway, which is mainly antibody-activated and hence part of the adaptive immune system, developed much later, but was identified first. The alternative pathway of complement activation starts with the spontaneous hydroysis of an internal thioester bond in the plasma complement component C3 to result in C3(H2O). The changed conformation of C3(H2O) enables binding of the plasma protein factor B which is in turn cleaved into fragments Ba and Bb by the plasma protease factor D. If C3b binds to the membrane of one of our own cells, the process of activation is inhibited by one of several different protective proteins, preventing damage to the cell. Facilitated by the bacterial surface, factor P (properdine) stabilizes the membrane- bound C3bBb complex. This complex, the C3 convertase of the alternative pathway, subsequently works as an amplifying tool, rapidly cleaving hundreds of additional C3 molecules. Soluble C3a diffuses into the surroundings, recruiting phagocytes to the site of infection by chemotaxis. This function, making the bacterium a "delicacy" for phagocytes, is called opsonization, from the Greek word for goody. The complement cascade does not stop at this point: further activation of components C5 through C9 ultimately result in the formation of membrane pores that sometimes succeed to lyse the bacterium. The smaller cleavage products C3a, C4a, C5a, sometimes called "anaphylatoxins", have additional functions in their own right: apart from attracting phagocytes, they cause mast cell degranulation and enhance vessel permeability, thereby facilitating access of plasma proteins and leukocytes to the site of infection. The lectin pathway of complement activation exploits the fact that many bacterial surfaces contain mannose sugar molecules in a characteristic spacing. These, by cleaving C4 and C2, generate a second type of C3 convertase consisting of C4b and C2b, with ensuing events identical to those of the alternative pathway.
The genera Dietzia cheap isoptin 40 mg fast delivery, Rhodococ- cus order isoptin 40 mg with amex, Nocardia buy 40mg isoptin, Gordona, and Mycobacterium have mycolic acids with increasing average numbers of carbon atoms. The arrangements of these mycolic acids are species-specific, a property that allows the identification of many species of myco- bacteria by gas-liquid, high-performance liquid or thin-layer chromatography (see chapter 14). There are also certain proteins called porins forming hydrophilic channels that permit the passive passage of aqueous solutes through the mycolic acid layer. Apparently, when the medium is disturbed, the capsule separates, leaving the lipophilic surface exposed. In fact, the capsule components have largely been recognized in culture filtrates but its struc- ture and location were resolved rather recently. The capsule contains proteins, polysaccharides and minor amounts of inner lipids, which are apparently in con- 3. In addition, a number of envelope-associated substances have been de- scribed, mostly lipids and glycolipids. The tubercle bacillus shares most ultrastructural features with other members of the genus, including non-pathogenic mycobacteria. Its distinctive ability to survive in mammalian hosts, its pathogenicity and its immunogenic properties seem to derive, at least in part, from the nature of some of the molecules of the bacterial wall (Ri- ley 2006, Smith 2003). The envelope of the tubercle bacillus seems to be a dynamic structure that can be remodeled as the microorganism is either growing or persisting in different envi- ronments (Kremer 2005). Besides, the expression of genes that putatively code for porins seems to be up regulated in certain environmental conditions, such as mildly acidified culture medium, as well as inside the macrophage vacuoles (Draper 2005). Acid fastness Unlike Gram-negative bacteria, mycobacteria do not have an additional membrane in the outer layers of the cell wall. However, mycobacteria do not fit into the Gram-positive category as the molecules attached to the cell wall are distinctively lipids rather than proteins or polysaccharides. The waxy cell wall of mycobacteria is impermeable to aniline and other commonly used dyes unless these are combined with phenol. Soon after, Ehrlich discovered the acid fast- ness of the tubercle bacillus, which has been the prominent characteristic of myco- bacteria up until now. The expression “acid-fastness” describes the resistance of certain microorganisms to decolorization with acid-alcohol solutions after staining with arylmethane dyes such as carbol fuchsin. This feature is of utmost practical 100 The Basics of Clinical Bacteriology importance in identifying the tubercle bacillus, particularly in pathological speci- mens. In spite of being a hallmark, the wall permeability to alkaline dyes and the mecha- nisms preventing their removal by acids are still not totally understood in molecular terms. The beading observed inside the cells was interpreted as accumulation of free dye rather than staining of particular structures, which led to the early hy- pothesis that alkaline stains are retained in the cytoplasm (Yegian 1947). Indeed, there is a parallelism between the increasing degree of acid fastness displayed by microorganisms in the genera Corynebacterium, Nocardia, and Mycobacterium, and the increasing length of mycolic acid chains in their walls. This correspon- dence suggests that the chemical binding of the dye to these molecules might be a determinant for acid fastness. Unimpaired mycolic acids are required to hinder the penetration of water- soluble dyes and bleaching acids (Goren 1978). Acid fastness seems to also be dependent on nutrients and oxygen tension, as suggested by fluctuations in staining observed in different culture conditions (Nyka 1971). Cord formation By microscopic observation, Robert Koch first described the arrangement of bacilli in braided bunches and associated this phenomenon with virulent strains of M. He also detailed the aspect of cultures in blood serum as compact scales which could be easily detached. In contrast, non-virulent mycobacteria and tubercle bacilli attenuated by prolonged cultures usually develop smooth colonies on solid media, form discrete mats in liquid media and distribute randomly in loose aggregates when smeared. The recognition of these two peculiarities, cording and crumbly colony formation, provides a reliable 3. Cell wall structure 101 and timely clue to the experienced microbiologist for the presumptive distinction of M. These distinctive characteristics of the virulent bacilli have been attributed to the trehalose 6, 6’-dimycolate. This compound, also known as cord factor, was de- scribed as an extractable glycolipid consisting of two mycolic acid molecules loosely bound in the outer layer of the cell wall (Noll 1956). A myriad of biological activities related to pathogenicity, toxicity, and protection against the host response have been attributed to this molecule. In this way it was demonstrated that beads coated with this substance generate an oriented hydrophobic interaction and aggregate in elongated structures similar to cords (Behling 1993). Five genes probably associated with cord formation were identified, but their real impli- cation has not been demonstrated (Gao 2004). Permeability barriers The tightly packed mycolic acids provide the bacillus with an efficient protection and an exceptional impermeability. In addition to the capsule, an even thicker layer of carbohydrate and protein outside the lipid layer impedes the diffusion of large molecules, such as enzymes, and protects the lipid layer itself. The shell restricts 102 The Basics of Clinical Bacteriology the permeability to most lipophilic molecules. Other substances can bypass this barrier through the porins, although this mechanism is not very efficient: M. Several experiments have been performed that have provided the rationale for the long believed concept that impermeability is at least one of the determinants for two M. Treatment with some drugs that are known to fray or somehow alter the surface architecture of the cells was shown to increase the susceptibility of M. In effect, at sub-inhibitory concentrations, ethambutol and di- methyl sulfoxide enhanced the activity of anti-tuberculosis drugs against M. Simi- larly, some antidepressants, such as chlorpromazine, have in vitro activity them- selves against the tubercle bacillus (Ordway 2003). The microorganism macro- molecular structure and physiological (metabolic) capabilities result in high adap- tation to the specific environment. In turn, the nutritional quality of the environ- ment determines the bacillus lifestyle and limitations, either in the natural habitat or in culture media, as do various physical conditions such as oxygen availability, temperature, pH and salinity. As the environment changes, the bacillus is able to bring into play different physiological pathways in order to survive even in harsh conditions. Nutritional and environmental requirements for growth 103 sis metabolism may shift from an aerobic, carbohydrate-metabolizing mode to one that is more microaerophilic and utilizes lipids (Segal 1956). These demonstrations, which were reported a long time ago, were supported in recent times by the com- plete sequencing of the M. This phe- nomenon may be related to the ability of the pathogen to grow or persist in host tissues where fatty acids may be the major carbon source (Neyrolles 2006) (see chapter 4). The tubercle bacilli can also grow in salt solutions using glycerol as a carbon source, ammonium ions and asparagine as nitrogen sources, and micronutrients. Indeed, the genome se- quence analysis confirmed that all the genes required for the formation of pyruvate are non-functional in M. Albu- min, which is normally provided by adding eggs or bovine serum albumin to the culture media, promotes the growth of these microorganisms. Other subsidiary media components may be used, such as Tween 80, a detergent that disperses the bacilli in liquid media. It was postulated that bovine serum albumin may bind the excess of oleate that can be released from the detergent up to toxic amounts.
Cytoskeletal components are also critical for cell motility buy isoptin 120 mg without a prescription, cell reproduction discount isoptin online american express, and transportation of substances within the cell buy genuine isoptin on-line. The cytoskeleton forms a complex thread-like network throughout the cell consisting of three different kinds of protein- based filaments: microfilaments, intermediate filaments, and microtubules (Figure 3. The thickest of the three is the microtubule, a structural filament composed of subunits of a protein called tubulin. Microtubules maintain cell shape and structure, help resist compression of the cell, and play a role in positioning the organelles within the cell. Cilia are found on many cells of the body, including the epithelial cells that line the airways of the respiratory system. Cilia move rhythmically; they beat constantly, moving waste materials such as dust, mucus, and bacteria upward through the airways, away from the lungs and toward the mouth. Beating cilia on cells in the female fallopian tubes move egg cells from the ovary towards the uterus. A flagellum (plural = flagella) is an appendage larger than a cilium and specialized for cell locomotion. The only flagellated cell in humans is the sperm cell that must propel itself towards female egg cells. The cytoskeleton plays an important role in maintaining cell shape and structure, promoting cellular movement, and aiding cell division. Microtubules grow out from the centrioles by adding more tubulin subunits, like adding additional links to a chain. In contrast with microtubules, the microfilament is a thinner type of cytoskeletal filament (see Figure 3. Actin fibers, twisted chains of actin filaments, constitute a large component of muscle tissue and, along with the protein myosin, are responsible for muscle contraction. In muscle cells, these long actin strands, called thin filaments, are “pulled” by thick filaments of the myosin protein to contract the cell. When a cell is about to split in half during cell division, actin filaments work with myosin to create a cleavage furrow that eventually splits the cell down the middle, forming two new cells from the original cell. As its name would suggest, an intermediate filament is a filament intermediate in thickness between the microtubules and microfilaments (see Figure 3. Intermediate filaments are made up of long fibrous subunits of a protein called keratin that are wound together like the threads that compose a rope. Intermediate filaments, in concert with the microtubules, are important for maintaining cell shape and structure. Unlike the microtubules, which resist compression, intermediate filaments resist tension—the forces that pull apart cells. There are many cases in which cells are prone to tension, such as when epithelial cells of the skin are compressed, tugging them in different directions. Intermediate filaments help anchor organelles together within a cell and also link cells to other cells by forming special cell-to-cell junctions. The nucleus is generally considered the control center of the cell because it stores all of the genetic instructions for manufacturing proteins. The nucleus of living cells contains the genetic material that determines the entire structure and function of that cell. The nuclei of the fused cells are conserved in the mature cell, thus imparting a multinucleate characteristic to mature muscle cells. Inside the nucleus lies the blueprint that dictates everything a cell will do and all of the products it will make. This membranous covering consists of two adjacent lipid bilayers with a thin fluid space in between them. Proteins called pore complexes lining the nuclear pores regulate the passage of materials into and out of the nucleus. Inside the nuclear envelope is a gel-like nucleoplasm with solutes that include the building blocks of nucleic acids. There also can be a dark-staining mass often visible under a simple light microscope, called a nucleolus (plural = nucleoli). These proteins are increasingly bundled and condensed into chromatin, which is packed tightly into chromosomes when the cell is ready to divide. Only very few cell types in the body do not divide, including nerve cells, skeletal muscle fibers, and cardiac muscle cells. Epithelial cells of the skin and gastrointestinal lining, for instance, divide very frequently to replace those that are constantly being rubbed off of the surface by friction. The two sides of the 108 Chapter 3 | The Cellular Level of Organization ladder are not identical, but are complementary. These two backbones are bonded to each other across pairs of protruding bases, each bonded pair forming one “rung,” or cross member. Most structural components of the cell are made up, at least in part, by proteins and virtually all the functions that a cell carries out are completed with the help of proteins. One of the most important classes of proteins is enzymes, which help speed up necessary biochemical reactions that take place inside the cell. Gene expression, which transforms the information coded in a gene to a final gene product, ultimately dictates the structure and function of a cell by determining which proteins are made. The sequence of bases in a gene (that is, its sequence of A, T, C, G nucleotides) translates to an amino acid sequence. Therefore, a gene, which is composed of multiple triplets in a unique sequence, provides the code to build an entire protein, with multiple amino acids in the proper sequence (Figure 3. The nucleotide sequence of a gene is ultimately translated into an amino acid sequence of the gene’s corresponding protein. A region at the beginning of the gene called a promoter—a particular sequence of nucleotides—triggers the start of transcription. While there are a few cells in the body that do not undergo cell division (such as gametes, red blood cells, most neurons, and some muscle cells), most somatic cells divide regularly. A somatic cell is a general term for a body cell, and all human cells, except for the cells that produce eggs and sperm (which are referred to as germ cells), are somatic cells. The human is a diploid organism, having 23 homologous pairs of chromosomes in each of the somatic cells. For example, the cells lining the gastrointestinal tract must be frequently replaced when constantly “worn off” by the movement of food through the gut. The cell cycle is the sequence of events in the life of the cell from the moment it is created at the end of a previous cycle of cell division until it then divides itself, generating two new cells. The Cell Cycle One “turn” or cycle of the cell cycle consists of two general phases: interphase, followed by mitosis and cytokinesis. Mitosis is the division of genetic material, during which the cell nucleus breaks down and two new, fully functional, nuclei are formed.
These surfaces tend to conform to one another buy cheap isoptin on-line, such as one being rounded and the other cupped purchase isoptin 240 mg otc, to facilitate the function of the articulation order 40mg isoptin with mastercard. In general, their size and shape is an indication of the forces exerted through the attachment to the bone. As with the other markings, their size and shape reflect the size of the vessels and nerves that penetrate the bone at these points. Bone Cells and Tissue Bone contains a relatively small number of cells entrenched in a matrix of collagen fibers that provide a surface for inorganic salt crystals to adhere. These salt crystals form when calcium phosphate and calcium carbonate combine to create hydroxyapatite, which incorporates other inorganic salts like magnesium hydroxide, fluoride, and sulfate as it crystallizes, or calcifies, on the collagen fibers. The hydroxyapatite crystals give bones their hardness and strength, while the collagen fibers give them flexibility so that they are not brittle. Although bone cells compose a small amount of the bone volume, they are crucial to the function of bones. Four types of cells are found within bone tissue: osteoblasts, osteocytes, osteogenic cells, and osteoclasts (Figure 6. When osteoblasts get trapped within the calcified matrix, their structure and function changes, and they become osteocytes. The osteoblast is the bone cell responsible for forming new bone and is found in the growing portions of bone, including the periosteum and endosteum. As the secreted matrix surrounding the osteoblast calcifies, the osteoblast become trapped within it; as a result, it changes in structure and becomes an osteocyte, the primary cell of mature bone and the most common type of bone cell. They can communicate with each other and receive nutrients via long cytoplasmic processes that extend through canaliculi (singular = canaliculus), channels within the bone matrix. If osteoblasts and osteocytes are incapable of mitosis, then how are they replenished when old ones die? These osteogenic cells are undifferentiated with high mitotic activity and they are the only bone cells that divide. The dynamic nature of bone means that new tissue is constantly formed, and old, injured, or unnecessary bone is dissolved for repair or for calcium release. They are found on bone surfaces, are multinucleated, and originate from monocytes and macrophages, two types of white blood cells, not from osteogenic cells. Osteoclasts are continually breaking down old bone while osteoblasts are continually forming new bone. The ongoing balance between osteoblasts and osteoclasts is responsible for the constant but subtle reshaping of bone. Bone Cells Cell type Function Location Osteogenic Develop into osteoblasts Deep layers of the periosteum and the marrow cells Growing portions of bone, including periosteum and Osteoblasts Bone formation endosteum Maintain mineral concentration of Osteocytes Entrapped in matrix matrix Table 6. Most bones contain compact and spongy osseous tissue, but their distribution and concentration vary based on the bone’s overall function. Compact bone is dense so that it can withstand compressive forces, while spongy (cancellous) bone has open spaces and supports shifts in weight distribution. It can be found under the periosteum and in the diaphyses of long bones, where it provides support and protection. Running down the center of each osteon is the central canal, or Haversian canal, which contains blood vessels, nerves, and lymphatic vessels. These vessels and nerves branch off at right angles through a perforating canal, also known as Volkmann’s canals, to extend to the periosteum and endosteum. The osteocytes are located inside spaces called lacunae (singular = lacuna), found at the borders of adjacent lamellae. As described earlier, canaliculi connect with the canaliculi of other lacunae and eventually with the central canal. Spongy (Cancellous) Bone Like compact bone, spongy bone, also known as cancellous bone, contains osteocytes housed in lacunae, but they are not arranged in concentric circles. Instead, the lacunae and osteocytes are found in a lattice-like network of matrix spikes called trabeculae (singular = trabecula) (Figure 6. The trabeculae may appear to be a random network, but each trabecula forms along lines of stress to provide strength to the bone. The spaces of the trabeculated network provide balance to the dense and heavy compact bone by making bones lighter so that muscles can move them more easily. In addition, the spaces in some spongy bones contain red marrow, protected by the trabeculae, where hematopoiesis occurs. The osteoblasts try to compensate but the new bone they lay down is weak and brittle and therefore prone to fracture. While some people with Paget’s disease have no symptoms, others experience pain, bone fractures, and bone deformities (Figure 6. Areas of bone resorption have an affinity for the ion, so they will light up on the scan if the ions are absorbed. In addition, blood levels of an enzyme called alkaline phosphatase are typically elevated in people with Paget’s disease. Bisphosphonates, drugs that decrease the activity of osteoclasts, are often used in the treatment of Paget’s disease. However, in a small percentage of cases, bisphosphonates themselves have been linked to an increased risk of fractures because the old bone that is left after bisphosphonates are administered becomes worn out and brittle. Still, most doctors feel that the benefits of bisphosphonates more than outweigh the risk; the medical professional has to weigh the benefits and risks on a case-by-case basis. Bisphosphonate treatment can reduce the overall risk of deformities or fractures, which in turn reduces the risk of surgical repair and its associated risks and complications. Blood and Nerve Supply The spongy bone and medullary cavity receive nourishment from arteries that pass through the compact bone. The arteries enter through the nutrient foramen (plural = foramina), small openings in the diaphysis (Figure 6. The osteocytes in spongy bone are nourished by blood vessels of the periosteum that penetrate spongy bone and blood that circulates in the marrow cavities. As the blood passes through the marrow cavities, it is collected by veins, which then pass out of the bone 230 Chapter 6 | Bone Tissue and the Skeletal System through the foramina. In addition to the blood vessels, nerves follow the same paths into the bone where they tend to concentrate in the more metabolically active regions of the bone. The nerves sense pain, and it appears the nerves also play roles in regulating blood supplies and in bone growth, hence their concentrations in metabolically active sites of the bone. By the sixth or seventh week of embryonic life, the actual process of bone development, ossification (osteogenesis), begins. There are two osteogenic pathways—intramembranous ossification and endochondral ossification—but bone is the same regardless of the pathway that produces it. Cartilage Templates Bone is a replacement tissue; that is, it uses a model tissue on which to lay down its mineral matrix. This framework is a flexible, semi-solid matrix produced by chondroblasts and consists of hyaluronic acid, chondroitin sulfate, collagen fibers, and water.
Dental erosion is increasing and is associated with dietary acids 120mg isoptin fast delivery, a major source of which is soft drinks cheap isoptin generic. Despite improved trends in levels of dental caries in developed countries discount 240mg isoptin, dental caries remains prevalent and is increasing in some developing countries undergoing nutrition transition. There is convincing evidence, collectively from human intervention studies, epidemiological studies, animal studies and experimental studies, for an association between the amount and frequency of free sugars intake and dental caries. Although other fermentable carbohydrates may not be totally blameless, epidemiological studies show that consumption of starchy staple foods and fresh fruit are associated with low levels of dental caries. Fluoride reduces caries risk but has not eliminated dental caries and many countries do not have adequate exposure to ﬂuoride. It is important that countries with a low intake of free sugars do not increase intake, as the available evidence shows that when free sugars consumption is ,15–20 kg/yr (,6–10% energy intake), dental caries is low. For countries with high consumption levels it is recommended that national health authorities and decision-makers formulate country-speciﬁc and community-speciﬁc goals for reducing the amount of free sugars aiming towards the recommended maximum of no more than 10% of Keywords energy intake. In addition, the frequency of consumption of foods containing free Dental diseases sugars should be limited to a maximum of 4 times per day. It is the responsibility of Dietary sugars national authorities to ensure implementation of feasible ﬂuoride programmes for Fluoride their country. Diet also plays a signiﬁcant The burden of dental diseases aetiological role in dental erosion, the prevalence of which Dental diseases are a costly burden to health care services. However, in modern societies, diet costs between 5 and 10% of total health care expenditures and nutrition play a relatively minor role in the aetiology of in industrialised countries exceeding the cost of treating periodontal disease (gum disease), another cause of tooth 1 cardiovascular disease, cancer and osteoporosis. This review will mainly focus on the major developing low-income countries, the prevalence rate of dental diseases, dental caries and dental erosion. Diseases dental caries is high and more than 90% of caries is of the oral mucosa, will not be reviewed in depth, as the untreated. The permanent dentition replaces the in the permanent teeth is generally low and mostly limited deciduous dentition from the age of 6 years and is 6 to the occlusal and buccal/lingual surfaces. In low-income countries, the cost of traditional developed countries, there is a trend for older adults restorative treatment of dental disease is disproportio- now to retain their teeth for longer, however, if the gums nately expensive in light of the low public health priority recede with age the roots of the teeth become exposed, and it would exceed the available resources for health and, being relatively less mineralised than the tooth 7 care. The large ﬁnancial beneﬁts of preventing dental crowns, are susceptible to decay known as ‘root caries’. Teeth are important in enabling consumption of a atrophy which subsequently reduces the mouth’s defence varied diet and in preparing the food for digestion. Teeth vitamins, zinc and iron, can inﬂuence the amount and also play an important role in speech and communication. Undernutrition coupled with adults reported impaired social functioning due to oral daily increased amount and/or frequency of sugars results disease, such as avoiding laughing or smiling due to poor in levels of caries greater than expected for the level of perceived appearance of teeth. In addition, dental formed by bacteria in dental plaque through the anaerobic 8 17 diseases cause considerable pain and anxiety. When sugars factors are likely to be exacerbated in less developed or other fermentable carbohydrates are ingested, the societies where pain control and treatment are not readily resulting fall in dental plaque pH caused by organic acids available. For example, in Thailand, half the children of age increases the solubility of calcium hydroxyapatite in the 12 claimed pain or discomfort from teeth within the past dental hard tissues and demineralisation occurs as calcium 3 is lost from the tooth surface. Similar patterns are observed in other demineralisation occurs is often referred to as the critical 9 10 11 pH and is approximately 5. Saliva is super-saturated with calcium and 12,13 phosphate at pH 7; this favours the deposition of calcium. Tooth loss may, therefore, impede the achievement of dietary goals related to the that cause demineralisation. Tooth loss has remains high enough for sufﬁcient time then complete also been associated with loss of enjoyment of food and remineralisation of enamel may occur. It is, therefore, clear that dental diseases have a detrimental effect on quality of life both in and the enamel becomes more porous until ﬁnally a 18 childhood and older age. The rate of demineralisation is Diet, nutrition and prevention of dental diseases 203 affected by the concentration of hydrogen and ﬂuoride there is little evidence for an association between diet and ions (i. Fluoride inhibits the periodontal disease, although current interest is focusing demineralisation process and the frequency with which on the potential preventive role of antioxidant nutrients. So overall, caries occurs disease is the presence of plaque, and prevention when demineralisation exceeds remineralisation. There is some evidence that ﬂuoride promotes remineralisation will be discussed to suggest that periodontal disease progresses more later. Overgrowth of the bacterial proﬁle, quantity and quality of the saliva, and periodontopathic organisms and yeasts has been observed 23,24 the time for which fermentable dietary carbohydrates are in malnourished African children. Streptococcus mutans intake is associated with increased plaque volume due to and Streptococcus sorbrinus are important bacteria in the the production of extracellular glucans, and there is a development of dental caries. The role of invertase splits sucrose into glucose and fructose, which dietary practices in the prevention of periodontal disease can be metabolised to produce mainly lactic but also other will not be discussed further. A low pH in plaque is ideal Nutrition and oral infectious diseases for aciduric bacteria such as streptococci, lactobacilli and Malnutrition consistently impairs innate and adaptive biﬁdobacteria as these are more competitive at low pH defences of the host, including phagocytic function, cell- than bacteria not associated with dental caries. Cellular often associated with other forms of tooth wear such as depletion of antioxidant nutrients promotes immunosup- abrasion and attrition (from over zealous oral hygiene and pression, accelerated replication rate of ribonucleic acid grinding of teeth, for example). Low salivary ﬂow rate infections and may lead to their evolution into life- or inadequate buffering capacity are factors that exacer- threatening diseases. Among the suspected causative factors are increased oral citric acid, phosphoric acid, ascorbic acid, malic acid, burden of free glucocorticoids and impaired host defence tartaric acid and carbonic acids found in fruits and fruit of saliva. No inﬂammatory oral lesions underscore the juices, soft drinks—both carbonated and still, some herbal association between malnutrition and oral health as teas, dry wines and vinegar-containing foods. Erosion reduces the size of interproximal gingival papillae and predominantly affects the teeth and in severe cases leads to total tooth impoverished young children (3–10 years of age) who are 21 destruction. Extensive dental erosion requires expensive generally immunocompromised by malnutrition and restorative treatment. Apart from severe vitamin destroys the soft and hard tissues of the oral and paraoral C deﬁciency, which results in scurvy-related periodontitis, structures. This is a count of the number of teeth in a person’s unacceptably high in many developed countries and is a mouth that are decayed, ﬁlled or extracted. For many countries there is very little Japan, the Scandinavian countries, the United Kingdom information, and few countries have undertaken repeated and the United States of America. There is some indication cross-sectional data on representative samples of the that the favourable trends in dental caries levels have population. Different countries may use different methods come to a halt or that the gradual decrease in caries 30 in epidemiological surveys of dental health and this may prevalence over the last half-century has stabilised. In Africa, the prevalence of dental caries in prevalence for both developed and developing countries young children is increasing in some parts and is for children aged 12 years. First, the distinct fall in the prevalence while it stays low in countries where a poor economy 31 of dental caries in developed countries, and second, restricts sugars consumption. Higher levels of decay industrialised countries has decreased in the last three 36 (dmft) were reported recently for Belarus (4. In developing countries where ﬂuoride is not available and populations have more opportunity to Dental caries in adults consume free sugars and other fermentable carbo- Being caries-free at age 12 does not imply being caries-free hydrates, the prevalence of decay is increasing. In for life, as dental caries affects adults as well as children South-east Asia and in some parts of Africa, studies 40,41 and the severity of the disease increases with age. In industrialised countries, there has been a fall in the There are insufﬁcient data available to comment on proportion of the adult population that are edentulous.
If patient continues to be agitated after 20 minutes cheap isoptin 120 mg on-line, increase the previous dose by 5 mg every 20 minutes until agitation subsides buy 240 mg isoptin amex. If starting with 2 mg and patient uncontrolled at 20 minutes cheap 120 mg isoptin free shipping, increase to 5 mg and follow guidelines above. Once patient responds to haloperidol, 25% of the loading dose required should be given every 6 hours on a scheduled basis. If patient is still not effectively sedated with maximum daily doses of haloperidol, consider using a different drug for sedation or the addition of a second drug with haloperidol (e. Extrapyramidal symptoms, parkinsonian symptoms, akathisias, dystonic reactions, and tardive dyskinesia (long-term use) b. To be used for complete or partial reversal of narcotics in suspected overdose or for diagnostic/therapeutic purposes. No clear benefit from treatment (Pollycarpou et al Anticonvulsants for alcohol withdrawal Cochrane Rev 2005). Alcoholic hallucinosis – Hallucinations that develop within 12-24 hours and resolve within 24-48 hours. Approximate 90% of individuals who drink etoh for >40+ consecutive days develop major withdrawal symptoms. In contrast, in individuals with sustained intake <30 days most develop only minor symptoms upon cessation of alcohol (Isbell et al Q J Stud Alcohol 1955). Controversy over use of anti-psychotics relates to the potential for these agents to lower seizure threshold. For all definitions below, pneumonia equals a new infiltrate, signs/symptoms of infection (fever, leukocytosis), purulent sputum, and/or worsening oxygenation. Anaerobes are rarely pathogens alone; only need to treat in chronic aspiration with pleuropulmonary involvement. Bacteriologic strategies using quantitative culture thresholds result in less antibiotic use; however suffer from methodologic difficulty (lab expertise, bronchoscopy). Severe Obructive Lung Disease : Asthma Acute severe asthma with impending respiratory failure Issue in Presentation and Severity 1. Acute Asphyxia Asthma Slowly progressive over days or weeks Rapid Onset Inflammation / Eos and Mucus Little inflammation / mucus- probably smooth muscle contraction Unlikely to improve rapidly – May rapidly improve with bronchodilators ++++ Initial Risk of high Barotrauma / autopeep +++++ +++ Atelectasis + Management: 1. Corticosteroids: Dose: Study: Solumedrol at 125 or 40mg better than 15mg Usual 60-125mg every 6-8 hrs overnight Type: No specifics c. Oxygenation: Usually not a major problem – if hypoxic likely to represent mucus plugging + lobar collapse. Hypoventilation reflects an inability to get sufficient air to the alveoli for gas exchange due to severe air-trapping. In addition there is complex V/Q mismatching with high airway pressures (peep) creating areas of lung without effective perfusion (essentially dead space). Synchrony: Tachypnea, air-trapping, and severe acidosis make it impossible for patient to synchronize – requires heavy sedation + paralysis d. Barotrauma: High air pressure generally reflects dynamic (airway resistance = peak – plateau pressure) but static (plateau pressure) is also increased due to air-trapping. If initial ventilation strategy results in significant stacking of breaths and thus autopeep or dynamic hyperinflation - eventually this will cause decreased venous return with hypotension, shock, cardiac arrest etc. The aim is to limit minute ventilation and maximize expiratory time, and thus reduce the risk of air- trapping. Daily Transcranial Doppler exams may detect impending spasm before clinical symptoms (stroke) develop. Other treatments of vasospasm include angiography w/angioplasty, and/or intra-arteial milrinone or papaverine (case reports). Refractory status epilepticus- continual seizures after 1-2 meds have been tried 20% of these patients go on to have persistent neurological defects- behavior, memory, emotional Incidence of status epilepticus- Less than 1 % of all seizures Management – 1. Hypertensive emergency- increase in systolic and diastolic blood pressure leading to end-organ damage A. The clinical differentiation between these two entities is the presence or absence of end organ damage not the level of blood pressure elevation. The aim is to lessen pulsatile load and force of left ventricular contraction to slow the propagation of the dissection. Definition: Hyponatremia is generally defined as a plasma sodium level of less than 135 mEq per L (135 mmol per L). Pseudohyponatremia: This condition results from increased percentage of large molecular particles in the serum relative to sodium. These large molecules do not contribute to plasma osmolality resulting in a state in which the relative sodium concentration is decreased, but the overall osmolality remains unchanged. Glucose molecules exert an osmotic force and draw water from the intracellular compartment into the plasma, thereby causing a diluting effect. Hypervolemic hyponatremic conditions: congestive heart failure, liver cirrhosis, and renal diseases such as nephrotic syndrome. Treatment: Step 1: Based on Na levels and severity of symptoms decide whether immediate treatment is required. In patients with chronic hyponatremia, overzealous and rapid correction should be avoided because it can lead to central pontine myelinolysis. In central pontine myelinolysis, neurologic symptoms usually occur one to six days after correction and are often irreversible. In patients with hypernatremia and depletion of total body Na content (ie, who have volume depletion), the free water deficit is greater than that estimated by the formula. Dialysis (diffusion): The movement of solutes from a high concentration compartment to a low concentration compartment. An electrolyte solution (dialysate) runs countercurrent to blood across a semi-permeable (small pore) filter. Ultra-filtration (convection) – Solute is carried (in solution) across a semipermeable membrane in response to a transmembrane pressure gradient (a process known as solvent drag). The rate of ultrafiltration depends upon the porosity of the membrane and the hydrostatic pressure of the blood. Intermittent hemodialysis is the most efficient – Large amounts of fluid can be removed and electrolyte abnormalities can be rapidly corrected. Continuous Renal Replacement Therapy: The concept behind continuous renal replacement techniques is to dialyse patients in a more physiologic way, slowly, over 24 hours, just like the kidney. The ultrafiltration rate is high, and replacement electrolyte solution is required to maintain hemodynamic stability. It is hypothesized that removal of mid sized inflammatory cytokines may play a role in improving outcome in sepsis. Pathophysiology: premature activation of trypsin in pancreatic acinar cells sets of inflammatory cascade.
Indirect ophthalmoscopy Indirect ophthalmoscopy can also be done using a bright hand held light source and a hand lens (5 - 7 x) cheap isoptin 40mg on-line. The hand lens could be as simple as a 7 - 5 x (28 -20 diopter) Bausch and Lomb plastic lens or a aspheric 20 buy line isoptin, 2 discount isoptin 120 mg with mastercard. Indirect ophthalmoscopy Periocular Nerve Blocks Subsequent examination techniques that involve manipulations, especially in an animal that is already exhibiting signs of ocular pain usually require the additional assistance of one or several periocular nerve blocks. Periocular Nerve Block 1 Periocular Nerve Block 1 Periocular Nerve Block 1 Periocular Nerve Block Method 1 Inject 0. A 25 x 5/8" needle should enter at a point just below the arch and penetrate until the tip hits the bone, then slide needle foward until the tip is at the crest of the arch. Periocular Nerve Block 2 Palpate a cord of tissue at the lowest point of the cranial portion of the zygomatic arch and place 0. Periocular Nerve Block 3 Find the supraorbital foramen by placing your thumb on the superior orbital rim and your middle finger on the edge of the supraorbital fossa; then slide your hand medially and as your two fingers separate; drop your index finger down to touch the skull. Usually your index finger will fall into the foramen at this point, unless you are dealing with a draft horse. There is a branch of the auriculpalpebral nerve that passes over the surface of the foramen and this block will provide mostly akinesia of the upper lid with some analgesia to the central upper lid. Periocular Nerve Block 3 Periocular Nerve Block 3 If more analgesia of the central upper lid is needed then anesthetic needs to be placed into the foramen. Sensory Blocks Special Examination Procedures Culture Schirmer Tear Test Sodium Fluorescein Eversion of Lids (Foreign Body Search) Culture A culture sample should be taken early in the exam and especially prior to instillation of fluorescein, topical anesthetics, mydriatics or eye wash with preservatives. It is Tears wise to compare one eye with the other to help access subtle deficiencies. If however, a Schirmer Tear Test needs to be done, this would be the time to do it; prior to the instillation of any topical solutions, especially an anesthetic and also prior to administration of a systemic analgesic/sedative. Sodium Fluorescein In order to identify breaks in the epithelial surface of the conjunctiva or cornea, sodium fluorescein is used to identify the de-epithelialized areas. The strip should not be touched directly to the cornea and application can either be by wetting the strip with eye wash and applying a drop of the fluorescein solution to the lid margin directly from the strip or by squirting it from a syringe on to the eye. This can be done by placing a fluorescein strip into the barrel of a disposable syringe with an attached needle hub (needle broken off flush with the hub). Eye wash is added to make a small amount of fluorescent solution and then the solution squirted onto the eye from a distance of at least six inches. Be careful, the hub of the disposable needle still has a small fragment of needle and could injure the eye. Sodium Fluorescein Sodium Fluorescein Fluorescence will occur with sun light, white light, cobalt blue light or a black light. Care should be exercised in handling these eyes for they are likely to rupture with a squint after the initial sting of the fluorescein when it is first applied to the eye. Topical Anesthesia Topical anesthesia in ophthalmology refers to the application of a anesthetic on the surface of the eye to alleviate minor discomfort from manipulations that the patient would ordinarily not tolerate otherwise. Eversion of the eyelids including the third eyelid, conjunctival scraping and biopsy, corneal scraping, nasolacrimal drainage apparatus manipulations and suture removal, would be examples of techniques that would necessitate this drug, in addition to sedation and possibly nerve block. Proparacaine is by far the most commonly used and is the least toxic of the three. Topical Anesthesia There is a limit to the magnitude of analgesia provided by a topical agent. After the topical anesthetic has been applied three or four times, and no further increase in depth occurs; one can then expect only increased duration of effect and toxicity. If after four applications of proparacaine in two minutes there is not enough perceived analgesia for what is being done, then another form of analgesia needs to be added. The twitch only needs to be applied at the moment of the manipulation for supplementation. Eyelid Eversion Eversion of the eyelids to evaluate the conjunctival cul de sacs can be aided with a muscle hook. Eyelid Eversion “Muscle Hook” This is a smooth relatively atraumatic ophthalmic instrument used in rectus muscle surgery that can be slipped over the lid margin followed by gently pulling the eyelid away from the globe while the examiner observes the condition of the conjunctival surfaces with a bright light and magnification. Eyelid Eversion Topical anesthetic after an auriculopalpebral block is usually necessary to do this. Some horses resist this instrument, yet have long and firmly fixed vibrissae that can be carefully used to draw the eyelid away from the globe, accomplishing the same goal of being able to look into the full extent of the cul-de-sac without using an instrument. For, just rolling the eyelid margin out with the thumb, for example, will allow visualization of the proximal palpebral conjunctival and at the same time compress the deeper cul de sac. Eyelid Eversion The third eyelid can also be everted to look on the bulbar surface. Avoid grasping over the free margin because of the potential for damage to the cornea. A generous application with additional eye wash will usually result in the appearance of dye in the distal nasal cavity after a few minutes. If the animal has a clinical sign of tears or ocular discharge and especially if there is no passive flow of fluorescein to the nose, the nasolacrimal system can be flushed. Gentile irrigation with preferably warm eyewash delivered with a syringe works well. Most average sized horses will accommodate a 5 French size and larger animals such as a draft horse may need an 8 French. Do not force and watch the respective distal opening for the first flow to characterize the material exiting. Conjunctival Cytology Occasionally it is necessary to perform a conjunctival scraping for cytology to characterize the inflammatory response and evaluate for bacterial organisms or evaluate for neoplastic cells or parasitic organisms. This can be done with a chemistry spatula, a Bard Parker Scalpel handle tip (part that accepts the blade but with out a blade attached) a Kimura spatula or the butt end (end opposite the sharp blade end) of a scalpel blade. Conjunctival Biopsy Biopsy of the conjunctiva for histopathology and or parasite evaluation can be performed on a standing horse after xylazine, auriculopalpebral nerve block and either a topical anesthetic or a subconjunctival (sublesional) injection of 2% lidocaine (0. At the time of the subconjunctival injection and when the tissue to be biopsied is picked up with a fine rat toothed forceps, the application of a lip or ear twitch is usually necessary and advisable. Avoid aggressive large biopsies of the conjunctiva, for prolapse of orbital fat could occur or suture the wound after the biopsy. Corneal Cytology Sampling of a corneal ulcer bed for culture usually requires a scraping with a spatula to obtain an adequate amount of material. Ideally, this should be done prior to the application of fluorescein or topical anesthesia due to the possibility of a bacteriostatic/cidal effect from these chemicals. If a sample can not be obtained with out topical anesthesia then anesthesia can be used. Academic pathology includes research and teaching, and the discipline of experimental pathology was derived from this. Clinical pathology is often referred to as laboratory medicine and includes a number of diagnostic disciplines.