Control of esophageal and lower esophageal sphincter function: neurohumoral and myogenic factors.
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Biomedical subjects
Publications and source records attributed to S Cohen.
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Pseudomonas aeruginosa grew in blood cultures taken from a 30-year-old woman with a 45% burn of second and third degree. Because of wound infection, skin grafting was unsuccessful and the wounds were left uncovered and treated topically with Eusol and saline solution. During this period 7 mg/kg gentamycin was administered to the patient daily; the blood level of the antibiotic was 3 microgram/ml, rather than the expected 8--12 microgram/ml in a patient without burns. On the eighth day, 40% of the administered dose was recoverable in the urine. With partial covering of the wounds, a dose of 5 mg/kg gentamycin daily gave blood levels of 6.5 microgram/ml. When most of the burn wounds were covered, a dose of 5 mg/kg gentamycin daily gave a blood level of 12 microgram/ml. Kidney function remained normal throughout the whole period. The possibility that gentamycin was eliminated through the burn wounds is suggested.
Pretreatment (12-48 h) of human fibroblasts with crude, human chorionic gonadotropin (HCG) was found to suppress cytomegalovirus infection and enhance productive herpes simplex type 1 (HSV) infection in vitro. Maximal effect on virus replication occurred at the time of maximal infectivity of control cultures (48 h and 6 days after viral innoculation for HSV and cytomegalovirus, respectively). The alteration in viral growth was not due to the HCG itself, but rather to epidermal growth factor, a contaminant of crude HCG. The effect of epidermal growth factor on viral infectivity was shown to be a cell-mediated event requiring protein synthesis.
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Epidermal growth factor (EGF) binds to JEG-3 cells, a tissue culture line of human choriocarcinoma. EGF also stimulates secretion of human chorionic gonadotropin (hCG) and to a lesser extent the secretion of free hCG-alpha.
The clinical and diagnostic features of a secondary type of achalasia of the esophagus are described in seven patients with various types of malignancies. Patients with secondary achalasia presented with dysphagia of short duration and marked weight loss; mean age was 64 years. Esophageal manometry showed features identical to those of idiopathic primary achalasia: aperistalsis, poor lower esophageal sphincter relaxation, and elevated sphincter pressure. Endoscopy and barium swallow showed evidence of a tumor in only two cases. Various types of malignancies may produce a secondary form of achalasia that has diagnostic features identical to those of primary achalasia and is best identified by its clinical presentation.
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The involvement of the immune system in the host response to tumors is complex and involves both lymphocytes and lymphocyte-derived mediators, as well as inflammatory cells and various other agents such as complement. These activies are not confined to cytodestructive processes; recent studies demonstrate that the migration characteristics of tumor cells may be modified by immunologically derived substances. The multiplicity of possible immune system-neoplastic cell interaction is unfortunately balanced by the multiplicity of mechanisms that serve to interfere with an effective immune response to tumors. These mechanisms may reflect pathologic derangements of normal immunoregulatory processes or may involve the production of suppressive substances by the tumors themselves. In either case, a number of genetic and other predisposing factors must contribute to the ultimate resolution of the battle between host and tumor. Successful strategies for immunologic intervention must take these parameters into account.
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The effectiveness of cimetidine for symptomatic relief in patients with chronic gastroesophageal reflux was studied in a multicenter, double blind clinical trial. Patients were entered into the study for a total of 8 weeks, receiving either cimetidine, 300 mg four times daily, or identical placebo tablets. Throughout the trial, frequent assessments were made of symptom severity and frequency, combined with careful measurement of antacid use. Esophagoscopy, esophageal acid sensitivity, and lower esophageal pressures were performed before and at the completion of the treatment period. Significant (P less than 0.05) decreases in symptom frequency and severity were noted throughout the study in the cimetidine-treated patients, as compared with the placebo group. This subjective improvement was corroborated by a concomitant decrease in antacid use, which was significantly (P less than 0.05) reduced in the cimetidine-treated group. In addition, significant improvement in esophageal acid sensitivity resulted from cimetidine therapy. No objective improvement in esophageal endoscopic appearance or sphincter pressures was noted. The results of this double blind trial indicate that cimetidine is more effective than the placebo for the relief of symptoms of gastroesophageal reflux.
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Rhesus monkeys vaccinated with merozoites in FCA are protected against challenge with several strains and variants of Plasmodium knowlesi. Vaccination induces sterilizing immunity which is species specific. Merozoite-blocking (inhibitory) antibody usually correlates with clinical immunity and protection can be passively transferred with immune sera provided these contain high levels of inhibitory antibody. However, vaccination using adjuvants other than FCA may induce inhibitory antibody without clinical protection. In addition, vaccinated animals may become susceptible to challenge 4-5 weeks after splenectomy, although inhibitory antibody levels are not reduced. These observations indicate that immunity induced by merozoite vaccination involves: (i) merozoite blocking (inhibitory) antibody, (ii) specific antibody or immune complexes acting synergistically with cytotoxic splenic cells stimulated by FCA.
The purpose of this study was to evaluate the effect of histamine phosphate and specific histamine antagonists on human lower esophageal sphincter (LES) pressure. Continuous intravenous infusions of histamine at doses of 2.0 to 40.0 microgram/kg-hr gave graded increases in LES pressure with a peak response of 378 +/- 4.6 mm Hg at 20.0 microgram kr-hr. The LES response was not altered by an H1-antogonist, diphenhydramine (50 mg, intravenously), but was completely blocked by infusion of the H2-antagonist, cimetidine (4.0 mg/kg-hr). Also, oral cimetidine (300 mg) antagonized any increase in LES pressure during histamine infusion at a dose shown to give the maximal LES response. Despite this effect of cimetidine in antagonizing the maximal LES response to histamine, oral cimetidine at 200, 300, and 400 mg failed to alter basal LES pressure over a 3-hr period. Cimetidine also failed to alter the LES response to intravenous pentagastrin or oral beef hydrolysate. These studies suggest that: (1) human LES pressure increases in response to intravenous histamine phosphate through its action at an H2-receptor; (2) the H1-receptor has no apparent role in the human LES response to histamine; and (3) H2-antagonism with cimetidine has no effect on the human LES basal pressure or its response to gastrin stimulation.