Low salt intake down-regulates the guanylin signaling pathway in rat distal colon

BACKGROUND & AIMS: Guanylin, an endogenous gastrointestinal peptide, causes the translocation of NaCl from interstitial fluid to the intestinal lumen. The aim of this study was to examine whether changes in dietary salt intake lead to compensatory changes in expression of the guanylin signaling pathway. METHODS: Rats received low-, normal-, or high-sodium diets for 1 week. Colonic guanylin expression was evaluated by Western and Northern blotting, rates of guanylin secretion by measuring biologically active guanylin released into the medium from colon explants, and expression of the guanylin receptor (C-type guanylate cyclase) by Northern blotting and bioassay. RESULTS: By every criterion, the low-salt diet reduced expression of guanylin to 30%-40% of the level found in control animals. Guanylin receptor expression was also decreased, although less dramatically and with a lower statistical significance. For both guanylin and guanylin receptor, the high-salt diet had no significant effect on expression. CONCLUSIONS: The data support the hypothesis that the guanylin pathway is down-regulated as an adaptive response to salt restriction.     

Immunity to jellyfish venoms: suppression of venom-induced immune responses in ultraviolet B-irradiated mice

Lymph node and spleen cells from mice immunized with sea nettle (Chrysaora quinquecirrha) venom exhibited a proliferative response after exposure to the homologous antigen or that of a related jellyfish, Physalia (Portuguese man-o'-war). Native venom was a more effective stimulant than heated, non-lethal venom. Ultraviolet light treatments administered to the skin either before or after venom sensitization suppressed the proliferative response of these internal immune cells.     

Prevention of bacterial endocarditis: recommendations by the American Heart Association

OBJECTIVE: To update recommendations issued by the American Heart Association last published in 1990 for the prevention of bacterial endocarditis in individuals at risk for this disease. PARTICIPANTS: An ad hoc writing group appointed by the American Heart Association for their expertise in endocarditis and treatment with liaison members representing the American Dental Association, the infectious Diseases Society of America, the American Academy of Pediatrics and the American Society for Gastrointestinal Endoscopy. EVIDENCE: The recommendations in this article reflect analyses of relevant literature regarding procedure-related endocarditis, in vitro susceptibility data of pathogens causing endocarditis, results of prophylactic studies in animal models of endocarditis and retrospective analyses of human endocarditis cases in terms of antibiotic prophylaxis usage patterns and apparent prophylaxis failures. MEDLINE database searches from 1936 through 1996 were done using root words endocarditis, bacteremia and antibiotic prophylaxis. Recommendations in this document fall into evidence level III of the U.S. Preventive Services Task Force categories of evidence. CONSENSUS PROCESS: The recommendations were formulated by the writing group after specific therapeutic regimens were discussed. The consensus statement was subsequently reviewed by outside experts not affiliated with the writing group and by the Science Advisory and Coordinating Committee of the American Heart Association. These guidelines are meant to aid practitioners but are not intended as the standard of care or as a substitute for clinical judgment. CONCLUSIONS: Major changes in the updated recommendations include the following: (1) emphasis that most cases of endocarditis are not attributable to an invasive procedure; (2) cardiac conditions are stratified into high-, moderate- and negligible-risk categories based on potential outcome if endocarditis develops; (3) procedures that may cause bacteremia and for which prophylaxis is recommended are more clearly specified; (4) an algorithm was developed to more clearly define when prophylaxis is recommended for patients with mitral valve prolapse; (5) for oral or dental procedures the initial amoxicillin dose is reduced to 2 g, a follow-up antibiotic dose is no longer recommended, erythromycin is no longer recommended for penicillin-allergic individuals, but clindamycin and other alternatives are offered.     

Chromosome structure inside the nucleus

Recent in situ three-dimensional structural studies have provided a new model for the 30 nm chromatin fiber. In addition, research during the past year has revealed some of the molecular complexity of non-histone chromosomal proteins. Still to come is the unification of molecular insights with chromosomal architecture.     

Free revascularized jejunal loop repair following total pharyngolaryngectomy for carcinoma of the hypopharynx: report of 90 patients

Ninety patients with carcinoma of the hypopharynx underwent pharyngolaryngectomy and reconstruction with a jejunal free autograft. Fifty-five patients had primary surgery and 35 salvage surgery for recurrence after radiotherapy. Following primary surgery 28 patients had postoperative radiotherapy and 27 did not. Complications occurred in 51 per cent of patients, the most common being necrosis of the jejunal graft (19 per cent); 12 per cent developed significant stenosis and 4 per cent died in the perioperative period. Eleven per cent of patients developed a fistula. The total number of complications diminished as the experience of the unit increased. Median follow-up was 4.9 years. Of patients treated with primary surgery, 48 per cent developed primary site recurrence (at 3 years) and 53 per cent neck node recurrence (at 5 years). The tumour-specific 5-year survival rate for all patients was 42 per cent. Following primary surgery 28 per cent survived for 5 years and after salvage surgery the rate was 59 per cent. Positive resection margins and extensive neck disease adversely affected survival (P = 0.02 and P = 0.001 respectively). The free revascularized jejunal graft is a safe and predictable method of repair following total pharyngolaryngectomy.