By G. Kayor. Deep Springs College.
As the length of intestine available for absorption decreases order synthroid 75mcg free shipping, the degree of polyhydramnios increases purchase 100 mcg synthroid with mastercard. Polyhydramnios more likely is observed in the fetus with a proximal obstruction cheap synthroid 200 mcg amex, such as esophageal atresia without tracheoesophageal ﬁstula or duodenal atresia, and not those with a distal obstruction, such as distal ileal or colonic atresia (Fig. The sonographic ﬁndings of a dilated proximal esophageal pouch and lack of ﬂuid in the stomach suggests esophageal atresia. Prominent upper abdomen ﬂuid collections representing the ﬂuid-ﬁlled stomach and duodenum suggest obstruction at the level of the duodenum, as in the case presented. Dilated loops of bowel with increased peristal- sis may be observed in a fetus with distal intestinal obstructions, while 36. Yes No Attempt to pass orogastric tube Obtain abdominal film Able to pass tube into stomach? Meconium peritonitis No Perforation from: Yes Volvulus Ascites Imperforate anus Atresia Intraperitoneal mass Retroperitoneal mass Obtain abdominal film Meconium ileus Choledochal cyst Hydronephrosis Renal mass Low Calcifications? No Hydrometrocolpos Obtain contrast enema Yes Ovarian cyst Pyloric atresia Duodenal atresia Meconium peritonitis Ileal atresia Malrotation with volvulus Perforation from: Meconium ileus Jejunal atresia Volvulus Meconium plug syndrome Atresia Small l colon syndrome Meconium ileus Hirschsprung’s disease Colorectal atresia Algorithm 36. Burd Low obstruction Small bowel No polyhydramnios High obstruction Small bowel Normal-caliber polyhydramnios coion Figure 36. Calciﬁcations can form when the peritoneal cavity is exposed to meconium, and their presence suggests an antenatal intestinal perforation. Morphologic abnormalities suggesting a chromosomal defect also may have been observed, prompting amniocentesis and chromosomal testing. Chro- mosomal defects are found in about 5% of infants with esophageal atresia (most frequently trisomy 18 and 21) and about 30% of infants with duodenal atresia (most commonly trisomy 21). Family and maternal history may provide additional insight into the cause of neonatal intestinal obstruction. Because a familial association has been reported for most causes, a family history of newborn or child- hood surgery for intestinal obstruction should be sought, and the cause should be determined, if possible. Family members with disorders and anomalies outside of the gastrointestinal tract also may suggest an eti- ology of neonatal intestinal obstruction. Almost half of neonates with small left colon syndrome are infants of diabetic mothers. Physical Examination A complete examination is mandatory for all neonates with suspected intestinal obstruction. Particular attention should be focused on the abdominal examination, on the perineal inspection, and on identifying other anomalies, including features suggesting a chromosomal disor- der. In the case presented at the beginning of the chapter, the presence of trisomy 21 provides indirect evidence supporting the diagnosis of duodenal atresia. Although difﬁcult to observe in most cases, gastroduodenal or high jejunal obstruction may result in epigastric distention with a scaphoid lower abdomen, as described in the case presented. As discussed pre- viously, mechanically ventilated neonates with esophageal atresia and 36. Neonatal Intestinal Obstruction 651 a tracheoesophageal ﬁstula also may exhibit abdominal distention. The abdomen should be examined for tenderness and masses, and the inguinal region should be inspected for hernia. The main features to evaluate are the general perineal appear- ance and anal position and patency. The anal canal normally is posi- tioned about halfway between the coccyx and base of the scrotum in males or the vestibule in females, and it is within a perineal depression surrounded by slightly pigmented skin. Variations from this standard suggest that a variant of imperforate anus may be present. Neonates with a short distance from the distal colon to the perineum (low imper- forate anus) may have a perineal depression with pigmentation without a patent anal canal. With observation during the ﬁrst 24 hours of life, meconium eventually may pass through a rectoperineal ﬁstula and be seen exiting on the perineum anterior to the normal anal posi- tion or at midline raphe of the scrotum or penis in males or vestibule in females.
Flagellum It is the organ of locomotion in bacterial cell and consists of thee parts order synthroid 25mcg on line. The basal body The basal body and hook are embedded in the cell surface while the filament is free on the surface of bacterial cell buy cheap synthroid 25 mcg on line. Pili (fimbriae) It is hair like structure composed of protein (pilin) Two types (Based on function) synthroid 100mcg discount. Sex pili: The structure for transfer of genetic material from the donor to the recipient during the process of conjugation. Spores Resting cells which are capable of surviving under adverse environmental conditions like heat, drying, freezing, action of toxic chemicals and radiation. Classification of bacteria Bacterial classification depends on the following characteristics. Morphology of bacteria When bacteria are visualized under light microscope, the following morphology are seen. Bacilli (singular bacillus): Stick-like bacteria with rounded, tepered, square or swollen ends; with a size measuring 1-10μm in length by 0. Spiral: Spiral shaped bacteria with regular or irregular distance between twisting. Staining of bacteria Bacterial staining is the process of coloring of colorless bacterial structural components using stains (dyes). The principle of staining is to identify microorganisms selectively by using dyes, fluorescence and radioisotope emission. Staining reactions are made possible because of the physical phenomena of capillary osmosis, solubility, adsorption, and absorption of stains or dyes by cells of microorganisms. Individual variation in the cell wall constituents among different groups of bacteria will consequently produce variations in colors during microscopic examination. Whereas, cytoplasm is basic in character and has greater affinity for acidic dyes. Because dyes absorb radiation energy in visible region of electromagnetic spectrum i. Direct staining Is the process by which microorganisms are stained with simple dyes. A mordant is the substance which, when taken up by the microbial cells helps make dye in return, serving as a link or bridge to make the staining recline possible. It combines with a dye to form a colored “lake”, which in turn combines with the microbial cell to form a “ cell-mordant-dye- complex”. It is an integral part of the staining reaction itself, without which no staining could possibly occur. A mordant may be applied before the stain or it may be included as part of the staining technique, or it may be added to the dye solution itself. An accentuator, on the other hand is not essential to the chemical union of the microbial cells and the dye. It does not participate in the staining reaction, but merely accelerate or hasten the speed of the 26 staining reaction by increasing the staining power and selectivity of the dye. Progressive staining - is the process whereby microbial cells are stained in a definite sequence, in order that a satisfactory differential coloration of the cell may be achieved at the end of the correct time with the staining solution. Regressive staining - with this technique, the microbial cell is first over stained to obliteratethe cellulare desires, and the excess stain is removed or decolorized from unwanted part. Differentiation (decolorization) - is the selective removal of excess stain from the tissue from microbial cells during regressive staining in order that a specific substance may be stained differentiallyh from the surrounding cell. Differentiation is usually controlled visually by examination under the microscope Uses 1. Basic stains are stains in which the coloring substance is contained in the base part of the stain. Acidic stains are stains in which the coloring substance is contained in the acidic part of the stain. Eosin stain Neutral stains are stains in which the acidic and basic components of stain are colored.
The frequency with which these diseases occur means that patients requiring chronic drug therapy will undergo periods when drug absorption might be expected to be higher or lower than “normal” effective synthroid 50mcg. Adverse reactions Locally irritating or sensitizing drugs must be used with caution in this route purchase synthroid 25 mcg on line. This contrasts with buy synthroid 100mcg on-line, for example, the buccal epithelium which is much more robust and less prone to irritation. The fragility of the tissue also means that this route is particularly sensitive to the adverse effects of penetration enhancers. Damage to the epithelium could result in compromised mucocilary clearance which is associated with respiratory disease. Some intranasally delivered drugs showing systemic absorption are given in Table 9. They are also available as metered-dose devices, which would be expected to give more reproducible dosing, as a mechanical actuation delivers a pre-determined volume to the patient. Thus the dose of drug received by the patient will be dependent on the concentration of drug in the formulation. Commercial examples of metered-dose sprays include Syntaris, Beconase and Rhinocort which deliver flunisolide, beclomethasone and budesonide respectively. As discussed above, nasal sprays tend to deposit at their impaction site, in the anterior, unciliated regions of the nasal cavity, where airflow associated with inspiration is high and mucociliary clearance is slow or erratic. Thus a drug moiety depositing in this region is cleared slowly and is transported over a large area en route to the pharynx. As described above, nasal drops, if administered correctly, deposit drug throughout the nasal cavity (Figure 9. However this also means that: • some drug is inevitably deposited on ciliated regions of the mucosa and is therefore immediately available for clearance; • a proportion of the dose actually deposits at the nasopharynx where it may be immediately swallowed and is therefore not available for nasal absorption. To ensure a complete coating of the nasal mucosa from the atrium to the nasopharynx, the method depicted in Figure 9. Since this is either unknown or inconvenient to most patients, variable drug absorption is likely to result, which would be unacceptable for drugs with a narrow therapeutic window. In this second slower phase, clearance of the drops is much faster than clearance of the spray, probably because most of the spray deposits on non-ciliated regions. Due to this faster clearance, nasal drops are more suitable for drug moieties which are rapidly absorbed. Drug molecules which diffuse across the nasal epithelium relatively slowly will need a longer contact time and may therefore be better administered as sprays. The bioavailability of the peptide drug desmopressin is greater from a metered-dose nasal spray than from drops. The success of this dosage form in promoting nasal absorption is evidenced by the commercial availability of nasal sprays for the systemic delivery of various peptide drugs, including buserelin, desmopressin, oxytocin and calcitonin. However, peptides and proteins generally have a molecular weight in excess of 1,000 Da and are therefore unlikely to be absorbed across the nasal mucosa in any appreciable amounts without pharmaceutical intervention. Strategies under development to promote drug absorption via the nasal cavity are detailed below. The mechanisms of absorption promotion proposed for the different compounds are numerous and it is likely that more than one mechanism is involved: Alteration of mucus layer Agents that decrease the viscoelasticity of mucus, for example anionic and cationic surfactants and bile salts, have been shown to increase absorption. Thus, the paracellular route becomes leakier, permitting increased absorption of substances that use this route. Reversed micelle formation The differing adjuvant activities of various bile salt species relate to their differing capacities to penetrate and self-associate as reverse micelles within the membrane. In reverse micelles, the hydrophilic surfaces of the molecules face inward and the hydrophobic surfaces face outward from the lipid environment. The formation of reverse micelles within the cell membranes may create an aqueous pore, through which drug moieties can pass. Extraction by co-micellization Solubilization of cell membrane lipids, for example the removal of cholesterol by surfactants such as bile salts and polyoxyethylene ethers. However, a serious drawback for the use of penetration enhancers may be their potential deleterious effect to the epithelial tissue, either directly, by perturbing vital cell structures and/or functions, or indirectly, by permeabilizing the epithelium and thus paving the way for inward penetration of toxic agents and organisms.
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