摘要:

SummaryConflicting data have been published in favor of or against a secretory effect of atrial natriuretic peptide (ANP) in the intestine. The reported effects resemble that ofEscherichia coliheat-stable enterotoxin (ST). In this work the effects of ANP were studied in well established experimental systems and compared with that of ST. Both peptides induced a prompt secretion of water, Na, and Cl with no effects on K net transport in the in vivo rat perfused jejunum. The addition of ST, but not of ANP, evoked an increase of short circuit current in rat intestinal mucosa mounted in Ussing chambers. ST induced a significant increase in guanylate cyclase activity in intestinal homogenates, whereas ANP showed no effect. No binding sites for ANP were detected in basolateral or brush border membranes, nor in isolated enterocytes by a suction filtration technique. In conclusion, ANP acts as a short-lived intestinal secretagogue in the rat. Its mechanism of action is different from that ofE. coliST and appears to be indirect, since is not mediated by specific intestinal receptors and is not evident in vitro.

ISSN:0277-2116    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

SummaryDefective jejunal sodium/proton exchange causes severe, congenital secretory diarrhea. We report a boy who presented typically in utero, but in whom diarrhea resolved during the first year of life. Pregnancy was complicated by polyhydramnios, and an ultrasound at 31 weeks showed a distended fetal small intestine. The abdomen was grossly distended at birth, and profuse secretory diarrhea began immediately. He subsequently thrived on breast milk and electrolyte supplements. Studies of jejunal brush border sodium/proton exchange at 6 months showed a partial defect. Nonequilibrium rectal dialysis showed rectal sodium and potassium transport to be intact. Diarrhea lessened after 9 months, and the patient subsequently required occasional laxatives. These observations suggest that there is a spectrum of congenital abnormality in this exchanger, and that in children with incomplete defects normal colonic sodium salvage can subsequently mask net small intestinal secretion.

ISSN:0277-2116    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

SummaryOvergrowth of aerobic and anaerobic bacteria in the upper small intestine is a common finding in persistent diarrhea. We hypothesized that a large dose of broad spectrum, nonabsorbable oral antibiotic would hasten recovery from persistent diarrhea by eradicating aerobic bacterial overgrowth. Sixty-eight patients were randomly assigned to treatment with either oral gentamicin (n = 33) or placebo (n = 35) for a period of 6 days. The two groups were comparable in their clinical features, stool weights, duodenal and fecal microflora, during an initial 24 h observation period before randomization. The proportion of patients recovering within 6 days post-treatment was similar in the antibiotic (45.2%) and placebo (50%) groups. The stool weights in the two groups during 24–72, 72–120, and 120–168 h of the study did not differ significantly. The percent mean weight gain (g) at 168 h post-treatment in the antibiotic (1.0± 5.1) and placebo (1.4± 5.3) groups also did not differ significantly (p = 0.8). A similar proportion of antibiotic- (61.3%) and placebo- (60.7%) treated patients had started to gain weight by the last day of the study. We conclude that oral gentamicin was no more effective than placebo in reducing purge rates, in achieving earlier recovery from diarrhea, and in promoting the earlier onset of weight gain in this study.

ISSN:0277-2116    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

SummaryRecent studies suggest that cyclosporine may be an alternative to colectomy in children with severe ulcerative colitis who fail traditional therapy with bowel rest and high-dose corticosteroids. We report the clinical course of two such children. Patient I received oral cyclosporine at 15 mg/kg/day for 1 week followed by 8 mg/kg/day for 6 weeks. Clinical remission occurred within 5 days and has been sustained for 24 weeks after azathioprine was substituted for cyclosporine. Patient 2 received oral cyclosporine at 7–8 mg/kg/day for 7 days after which colectomy was performed due to lack of clinical improvement. Blood cyclosporine levels for patient 1 ranged from 95 to 406 ng/ml and for patient 2 from 36 to 65 ng/ml. Sigmoid colonic tissue cyclosporine concentrations for patients 1 and 2 were 10,058 and 3,205 ng/g, respectively. The patient who responded had significantly higher blood and colonic tissue cyclosporine concentrations than the patient who did not respond. Further studies with larger numbers of patients are needed to determine if there is a correlation between blood and colonic tissue cyclosporine concentrations and clinical response.

ISSN:0277-2116    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

SummaryEicosanoids, derivatives of arachidonic acid, play a role in several inflammatory diseases of the bowel. To determine whether prostaglandin E2(PGE2), leukotriene B4(LTB4), and leukotriene C4D4E4(LTC4D4E4), have a role in hypoxic insult to the intestine, we examined the levels of these mediators in a hypoxic neonatal rabbit model. One group of animals underwent hypoxic insult postnatally, the second group did not undergo hypoxia and served as a control. The levels of PGE2, LTB4, and LTC4D4E4were determined by radioimmunoassay. PGE2in the hypoxic group was 1,779± 142 pg/mg protein (mean± SD) as opposed to 2,380± 197 pg/mg protein in the control group (p < 0.02). LTB4level was 5,446± 3,492 pg/mg protein in the hypoxic rabbits and 3,362± 2,570 pg/mg protein in the control group (p < 0.03). There was no statistically significant difference in the level of LTC4D4E4between the two groups. Our study shows that hypoxia shifts the arachidonic acid metabolism toward enhanced lipoxygenase activity with a resultant increase in LTB4levels and a concomitant decrease in cyclooxygenase activity with reduced PGE2levels in the bowel. The shift in the balance between these eicosanoids may play a role in the pathogenesis of ischemic-hypoxic bowel diseases by enhancing the inflammatory response in the intestine, and simultaneously, diminishing cytoprotection.

ISSN:0277-2116    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

SummaryThis study was designed to determine the cardiac, respiratory, and arousal responses to an esophageal acid infusion test in near-term infants free from neurological, gastroesophageal, and cardiopulmonary disease at time of testing during active sleep. Eight infants (gestational age 28–37.5 weeks, postconceptional age 36–40 weeks) were tested. Using standardized procedures and timing, we compared the cardiac, respiratory and arousal responses during a control period and during distal esophageal saline and acid infusion periods. The duration of each of these periods was 5 min. The pH of the acid infusion was 2.2. We found that this mild distal esophageal acid infusion test induced significant prolongation of the interval between successive electrocardiogram R waves compared with control and saline infusion periods (806.5± 145.7 ms, 478.8± 49.4 ms, and 468.8± 37.2 ms, respectively; p < 0.01) and of the duration of the respiratory cycle (2.9± 0.7 s, 1.5± 0.3 s, and 1.5± 0.2 s, respectively; p < 0.01). Esophageal acid infusion elicited significant electroencephalogram (EEG) arousal responses. The number of the EEG arousals was significantly increased during the acid period as compared with control and saline infusion periods (2.9± 1.4, 0.5± 0.5, and 0.4± 0.5, respectively; p < 0.01). Total arousal duration was significantly increased during acid as compared with control and saline infusion periods (42± 17.5 s,4.5± 5.1 s, and 3.5± 5.0 s, respectively; p < 0.01). We conclude that distal esophageal acid stimulation elicits significant cardiac, respiratory, and EEG arousal responses in near-term infants during active sleep.

ISSN:0277-2116    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

SummaryPreviously, we reported catch-up weight gain, growth, and improved lung function in a group of malnourished cystic fibrosis (CF) children receiving aggressive nutritional supplementation for 1 year compared with a forced expiratory volume in 1 s (FEV1)-, height-, and sex-matched comparison group receiving standard therapy. To evaluate long-term effects, the clinical progress of both groups has been studied over a 5 year period. The supplemented group (n = 10) received supplements for a median of 1.35 years to achieve nutritional rehabilitation. Compared with the nonsupplemented group (n = 14), the previously supplemented group had lower mortality (2 vs. 4, N.S.) and significantly greater weight and height z scores at 4 and 5 years. The progression of pulmonary function abnormalities as measured by FEV1and forced vital capacity (FVC) slopes was greater at 3 years in the nonsupplemented group (FEV1, p < 0.05) but no significant differences in rates of deterioration of pulmonary function were seen after 5 years in the two groups of survivors. We conclude that intensive nutritional support for 1 year has both short- and long-term effects on nutrition and growth, still evident some years after the cessation of this therapeutic modality. Supplementation for periods of longer than 1 year may produce greater gains and possibly prolong the improvement in pulmonary function observed in the earlier study.

ISSN:0277-2116    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

SummaryPatients with cystic fibrosis (CF) often exhibit malabsorption despite the use of supplemental pancreatic enzymes. Unabsorbed carbohydrates and amino acids can serve as substrates for large intestine anaerobic fermentation, thus increasing excretion of short-chain fatty acids (SCFA) in the feces. Nine patients with CF on regular pancreatic enzyme supplementations in the age range of 5–11 years and one older patient were studied. Three-day stool samples were collected, as were 72–h food records. Stools were analyzed for gross energy, total nitrogen, fat content, and SCFA concentration. A significant difference was found between CF and normal controls in total caloric excretion due to fat malabsorption. No significant difference was found between CF and normal controls in protein or SCFA excretion. Fat excretion as percentage of fat intake was significantly increased in CF patients: 35.3± 10.2% versus 8.0± 3.0%, respectively. These data suggest that carbohydrate supplementation could be more widely used to increase caloric intake in CF patients without causing secondary osmotic diarrhea.

ISSN:0277-2116    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

SummaryWe investigated the ability of meconium, feces from human milk-fed (HMF) newborns, and feces from formula-fed (FF) newborns to inhibit adhesion of S-fimbriated E. coli to human buccal epithelial cells. S-fimbriae are a common property ofE. colistrains causing sepsis and meningitis in neonates. Meconium had the highest content of neuraminic acid and the strongest inhibitory effect on bacterial adhesion. HMF also exerted high inhibitory activity while FF was markedly less active: To achieve inhibitory effects comparable to HMF a sixfold amount of FF was required. Glycoproteins from excretions were separated by gel chromatography. Fractions obtained were analyzed for adhesion-inhibiting activity. In all excretions analyzed, the mucin-containing fraction could be identified as the major inhibitory component. Inhibition was probably mediated by specific interaction of this fraction with S-fimbriae, as shown by binding of isolated fimbriae on Western blots after electrophoretic separation of glycoproteins. In conclusion, our data support the view that the mucin-containing fraction from meconium and human milk exerts antibacterial functions by preventing adhesin-mediated binding of pathogenic bacteria to mucosal epithelia.

ISSN:0277-2116    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

SummaryThe presence of gliadin-specific IgA and IgG antibodies in colostrum and serum of 140 newly delivered mothers was assessed by enzyme-linked immunosorbent assay. In addition, cow's milk protein (CMP)-specific IgA was determined in the colostrum samples. From 14 of the mothers longitudinal milk samples were obtained after 1 and 2 months of lactation and from 12 mothers after 3 months. Gliadin-specific IgA was found in 97.1% and gliadin-specific IgG in 9.3% of the colostrum samples. Gliadin-specific IgA was detected in mature samples but at significantly lower levels after 1, 2, and 3 months of lactation (p < 0.01) as compared with colostrum. Gliadinspecific IgA was found in 2.8% of the serum samples and gliadin-specific IgG in 40%; however, the levels of both isotypes were low. CMP-specific IgA was found in 78.1% of the colostrum samples. It is concluded that IgA antibodies to two common food proteins are frequently found in human milk and that food-specific IgA present in milk may play a role in adapting the infant's immune reactions to food antigens in the gut.

ISSN:0277-2116    

出版商:OVID    

年代:1992

数据来源: OVID