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Biomedical subjects

J P Buts

Publications and source records attributed to J P Buts.

At least 73 records · Page 4Linked to original sources
PubMed1987

Cellular adaptation of the rat small intestine after proximal enterectomy: changes in microvillous enzymes and in the secretory component of immunoglobulins.

To investigate the adaptation of functions expressed by the villous and crypt cell of the intestinal mucosa after intestinal resection, a 50% proximal enterectomy or a single transection was performed in 16 growing rats weighing 175-200 g. Ten days following the enterectomy, we determined the mucosal mass parameters (weight, protein, and DNA content), the activity of microvillous enzymes (lactase, sucrase, and aminopeptidase) in villus cells, and the concentration of the secretory component of immunoglobulins in crypt cells isolated from the proximal intestinal remnant. Mucosal hyperplasia was attested by the finding that mucosal weight, protein, and DNA content per cm of intestinal length were significantly (p less than 0.01) higher (+29 to +48%) in the resected group than in transected controls. The specific activity of lactase, sucrase, and aminopeptidase were significantly (p less than 0.05) lower (-23 to -56%) in villous cells isolated from the intestinal remnant of resected rats compared to controls. Sucrase activity was depressed in each cell fraction of the entire villous-crypt unit resulting in a lower villous to crypt gradient of enzyme activity. Km for the enzyme determined in villous cells was similar in both groups but the Vmax was reduced proportionally to the enzyme activity in the resected group indicating less enzyme per cell. By contrast, the concentration of secretory component measured by an immunoradiometric assay in both villous and crypt cells was significantly (p less than 0.05) increased (+37 to 45%) following proximal enterectomy. Our data indicate that the response of the epithelial cell to intestinal resection varies according to the metabolic function and that the mechanism of adaptation at the cellular level is complex.

Adaptation, Biological↗
PubMed1986

Prevalence and treatment of silent gastro-oesophageal reflux in children with recurrent respiratory disorders.

Thirty-six infants and children presenting with recurrent respiratory disorders (RRD) as the sole clinical symptom including bronchial asthma (6), recurrent obstructive bronchitis with or without wheezing (18), chronic nocturnal cough (3), recurrent episodes of pneumonia (3), recurrent pharyngitis (3) and recurrent laryngitis (3) were investigated for associated gastro-oesophageal reflux (GER) by oesophagram, endoscopy and continuous 24 h pH monitoring of the distal oesophagus. The pH monitoring criteria were selected on the basis of a preliminary study comparing statistically measurements of 32 variables recorded in 15 patients who all had clinical, radiological and endoscopic evidence of GER and in 8 asymptomatic controls. Although patients with symptomatic GER differed significantly from the asymptomatic ones for 27 variables examined, 6 variables emerged as having the highest value for discrimination (overlap score 0-1). Among these, the Euler-Byrne index (number of reflux pH less than 4 + 4 times the number of reflux episodes of more than 5 min), the percentage of total reflux time and the number of reflux episodes 1 h post-cibal scored 0 (no overlap). GER was considered to be present when at least five of these six parameters were abnormal. The overall incidence of GER in children with RRD was 41% (15) when detected by oesophagram and 61% (22) when diagnosed by pH monitoring criteria. In the children with bronchial asthma or with recurrent laryngitis, the percentage of reflux time during sleep was about 40 times higher than in asymptomatic controls and 2 times higher than in those with symptomatic GER.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1986

Alteration of intracellular synthesis of surface membrane glycoproteins in small intestine of iron-deficient rats.

We studied the activity and kinetic parameters of microvillous enzymes in intestinal villous cells and the concentration of the secretory component (SC) of p-immunoglobulin A in subcellular fractions of crypt cells in 35-day-old rats made iron deficient from birth and in controls. The aim of the study is to investigate the biochemical basis for the decreased activity of brush-border disaccharidases observed in growing animals with chronic iron deficiency. In rats made iron deficient, the specific (per unit protein) and the total (per total intestinal length) activities of sucrase, lactase, maltase, aminopeptidase, and diamine oxidase were decreased from -17 to -66% compared with the activities measured in the controls. The lower activity of sucrase in the brush-border membrane of the iron-deficient rats was associated with much slower enzyme synthesis rate than in control animals. Km of sucrase was identical in both iron-deficient rats and controls, but the maximum velocity of enzyme reaction was reduced proportionally to the enzymatic activity, indicating a lesser amount of enzyme rather than an inactivation. Electron microscopy of epithelial villous cells from iron-deficient rats revealed a marked rarefaction of secretory granules (transport vesicles) without apparent change in the morphology of the brush-border membrane or of cellular organelles. In villus and crypt cells isolated from the jejunum of iron-deficient rats, SC concentration was reduced to a level about half that of the controls. When SC concentration was measured in subcellular fractions of crypt cells, SC content in each fraction was two to three times lower in iron-deprived rats than in controls without evidence of accumulation of the protein at a given subcellular level.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Response of human and rat small intestinal mucosa to oral administration of Saccharomyces boulardii.

To evaluate the response of the small intestinal mucosa to Saccharomyces boulardii (S.b.), a yeast widely used in some countries as an adjuvant drug with oral antimicrobial therapy, seven healthy adult volunteers were treated with high doses of lyophilized S.b. (250 mg four times per day) for 2 wk. A peroral jejunal suction biopsy was performed on days 0 and 15 of the study. Compared to the initial biopsy, histological examination of the posttrial biopsy revealed no morphological alteration nor change in villus height or crypt depth. After treatment, the specific activity (per U protein) of sucrase, lactase, and maltase was, respectively, increased by 82% (p less than 0.05) 77% (p less than 0.05), and 75% (p less than 0.05) over the basal activity of the enzymes measured on day 0, whereas mucosal protein content remained unchanged. Similar findings were found in the jejunum of adult rats treated for 5 days with either viable or killed S.b. cells. The changes in total enzyme activity (per jejunal segment) paralleled the changes in specific enzyme activity. In vitro assays on freshly prepared suspensions of S.b. (6.0 X 10(8) viable cells/ml) evidenced a high activity for sucrase (mean +/- SE: 8 364 +/- 1280 U X g X protein-1) but no maltase, neutral lactase, acid beta-galactosidase, or aminopeptidase activity. To determine whether treatment with S.b. could influence the incorporation rate of neutral lactase into the brush border membrane, 14-day-old sucklings treated either with saline or with S.b. were given intraperitoneally a dose of 20 microCi D-[1(14)C] glucosamine 3 hours before sacrifice.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1985

Upper airway lesions in children after accidental ingestion of caustic substances.

Of 33 children admitted within 24 hours after accidental ingestion of a caustic substance, 14 (42.5%) had evidence of upper airway lesions on direct laryngoscopy. Three patients, 10 to 12 months old, needed endotracheal intubation for acute respiratory obstruction; four patients younger than 2 years had severe dyspnea without obstruction; seven patients had mild or no respiratory symptoms. All were discharged without respiratory sequelae, although esophageal stenosis developed in six patients. Nine of 13 patients younger than 2 years, compared to five of 20 patients older than 2 years, had upper airway lesions (P less than 0.01). The frequency of respiratory tract lesions was higher in patients with severe esophagitis. Eleven of 17 patients with severe esophagitis, compared to three of 16 with mild inflammation, had respiratory tract lesions (P less than 0.025). No specific caustic substance predisposed to upper airway lesions.

Ampicillin↗
PubMed1985

Role of dietary protein adaptation at weaning in the development of the rat gastrointestinal tract.

To evaluate the role of the quantitative adaptation in dietary protein at weaning in the growth and maturation of the rat gastrointestinal tract, we studied parameters of tissue mass, DNA synthesis, and enzyme activities in suckling pups weaned by day 17 to a semipurified synthetic, isocaloric diet that contained either 8 or 27% casein (controls). Rats of both groups were studied on days 21, 28, and 35 postpartum. On day 21, protein restriction had little effect on mean body weight, wet stomach and liver weight, gut length and colonic, jejunal or ileal mucosal weights per centimeter, whereas on day 35, all these tissue mass parameters were significantly (p less than 0.01 versus controls) depressed in the 8% protein group. DNA and protein content expressed per intestinal segment or per total organ and the protein/DNA ratio paralleled the changes in tissue mass, except that total DNA of the small intestine was decreased by 33% (p less than 0.01 versus controls) in 21-day-old rats with protein restriction. In the same age group, DNA synthesis rate, measured by the incorporation rate of [3H]-thymidine per milligram tissue DNA, was markedly depressed in the small intestine (4-fold decrease; p less than 0.001 versus controls) and in the liver (2-fold decrease; p less than 0.05 versus controls) while in the colon the effect of protein restriction occurred later (day 35).(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1985

Localized absence of colonic musculature: an unusual cause of perforation in a colonic esophageal transplant.

A 4 1/2-year-old boy underwent subtotal esophageal substitution by left colon for caustic soda stricture. The transposed colon had to be removed for perforation 9 days later, and pathological examination showed several tiny perforations in an area 1.8 cm in diameter where the colonic wall was thin and devoid of muscularis. Arguments are presented to show that this absence of muscle coat is congenital. The perforations are thought to be the result of minimal ischemia in a colonic wall weakened by the defect.

Child, Preschool↗
PubMed1985

[Liver transplantation in children].

Liver transplantation has become a clinical therapeutic modality for end stage liver diseases. The results achieved in children are better than in adults: in T.E. Starzl unique experience in Pittsburgh, USA, the survival rate at one and four years are 75 and 70% respectively. Complete rehabilitation of these children can nowadays be expected. Between March 1984 and June 1985, 8 children received an orthotopic liver transplantation at the University of Louvain Medical School in Brussels, Belgium; one child received two transplantations after acute and irreversible rejection of a first ABO incompatible graft. The indications were biliary atresia in five (polysplenia in one), biliary hypoplasia in one, alpha-1-antitrypsine deficiency in one and Crigler-Najjar syndrome type I in one. The age of the patients at the time of liver replacement was 12 to 18 months in four, 8 to 13 years in four. Six patients are alive after 17, 14, 12, 10, 3 and 3 months; the two youngest children deceased during the first postoperative month. The Kaplan-Meyer one year survival rate is 75%; all surviving children are in excellent clinical condition with a normal liver function. The 9 transplanted livers were harvested from multiorgan cerebral death donors with the exception of one neonate whose liver alone was removed; 4 were retrieved locally, the five others were offered by foreign hospitals through the organ procurement agencies (Eurotransplant, France-Transplant, U.K. Transplant). Due to appropriate logistics with air flight transportation of the harvesting team when indicated, the total ischaemia time was kept below 6 hours in every case. Two small children underwent a left lobe orthotopic transplantation after ex vivo right trisegmentectomy of the liver retrieved from an older donor with one long term survival. The indications for liver transplantation in children are end-stage liver diseases consisting of a) cholestatic diseases among which the most frequent is biliary atresia after unsuccessful Kasai procedure followed by familial cholestasis (Byler syndrome) and the paucity of the intrahepatic bile ducts of the syndromatic (Alagille syndrome) or non syndromatic type. b) the metabolic diseases resulting either in cirrhosis with liver failure (alpha-1-antitrypsin deficiency, Wilson disease, glycogen storage disease type I and IV, protoporphyria) or in extrahepatic complications of enzymatic deficiency of an otherwise normally functioning liver (Crigler-Najjar syndrome type I, familial hypercholesterolemia and perhaps oxalosis). c) the hepatocellular diseases either chronic with cirrhosis of various origin or acute, eg. toxic hepatitis.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1985

Ontogenic changes in secretory component expression by villous and crypt cells of rat small intestine.

In order to determine whether the rat small intestine exhibits quantitative changes in the synthesis of the secretory component (SC) during growth, epithelial villus and crypt cells were isolated from jejunal segments at intervals after birth up to adulthood. SC concentration was measured in each cell fraction by immunoradiometric assay and compared to sucrase activity, an enzyme marker of the differentiated villus enterocyte. The following results were observed. (i) Adult rats showed a characteristic decreasing concentration gradient of SC from the crypts (mean concentration in crypt cells: 636 +/- 173 ng/mg protein) to the villus tip (mean concentration in villus cells: 152 +/- 17 ng/mg protein). This gradient was the reverse of that found for sucrase activity. (ii) In young sucklings (10 days old), SC was virtually absent in both villus and crypt cells, but its concentration progressively increased in weanling rats and reached adult levels by day 40 postpartum. (iii) The crypt to villus cell gradient of SC, absent in sucklings up to day 20, developed during the fourth postnatal week. (iv) Treatment of 10-day-old suckling pups with pharmacological doses of either corticosterone or L-thyroxine for 3 consecutive days failed to induce the precocious synthesis of SC by jejunal enterocytes, but produced significant (P less than 0.01) decreases in concentration. Under the same conditions, sucrase activity was markedly enhanced. In conclusion, major changes in the ability of the immature crypt cell to produce the specific receptor for transepithelial transport of polymeric immunoglobulins occur during the fourth week of rat life. The initiation of this ontogenic process is not triggered by the dietary and hormonal changes known to control the maturation of other functions linked to the differenciated villus cell, such as sucrase activity.

Animals↗
PubMed1984

Role of dietary iron in maturation of rat small intestine at weaning.

The weanling process is characterized by the transition from a liquid diet poor in iron (rat milk) to a solid diet high in iron (chow pellets). To examine the effects of iron content of the weanling diet on terminal maturation of rat small intestine, suckling pups, nursed by iron-sufficient mothers, were weaned by day 16 onto a solid basal diet that was either deficient [low-iron diet (LID): 0.5 mg iron/100 g solid] or high [high-iron diet (HID) controls: 30 mg iron/100 g solid] in iron. The animals were studied during or at the end of the 4th postnatal wk. By day 17 rats weaned onto the LID exhibited an initial rise in jejunal sucrase activity as did their controls, but the activity plateau of the enzyme was reduced to a level 60% of the controls. On day 28 iron-deprived rats were anemic and showed significant decreases (P less than 0.01 compared with HID rats) in the activity of jejunal sucrase (-57%), neutral lactase (-83%), and maltase (-46%), whereas villus height, crypt depth, mucosal mass parameters, ileal acid beta-galactosidase activity, mucosal protein, and DNA synthesis rates were equivalent in LID and HID groups. The concentration of the secretory component, a glycoprotein synthesized by the intestinal crypt cell, was markedly depressed (P less than 0.01 vs. controls) in the jejunum (-54%) and ileum (-79%) of iron-deprived rats. When D-[1-14C]glucosamine was injected intraperitoneally, incorporation of the label into jejunal and ileal brush-border proteins was two to three times lower for iron-deficient rats than for controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Intestinal development in the suckling rat: effects of weaning, diet composition, and glucocorticoids on thymidine kinase activity and DNA synthesis.

The present study was designed to determine whether the ontogenic changes in the salvage pathway for DNA synthesis of suckling rat intestine could be causally related to physiologic events during the weaning period. The intestinal activity of soluble thymidine kinase, extremely low in young sucklings (d 11, 0.057 +/- 0.007 nmol X min-1 X g tissue-1), increased dramatically between d 18 and 22 postpartum and reached a plateau (19.8 +/- 0.5 nmol X min-1 X g tissue-1) at the fourth postnatal week. Rat pups prevented from weaning showed an initial rise in the enzyme synthesis by d 18 as did their littermates weaned onto an adult diet. Compared with 22-d-old rats weaned onto chow pellets (14.1 +/- 2.1 nmol X min-1 g tissue-1), thymidine kinase concentration was reduced by one-half in rats of the same age, fed on mother's milk alone (6.5 +/- 0.7 nmol X min-1 X g tissue-1) or on a liquid artificial diet either high in fat (mimicking rat milk, 7.4 +/- 0.6 nmol X min-1 X g tissue-1) or high in carbohydrate mimicking chow, 6.4 +/- 1.3 nmol X min-1 X g tissue-1). The relative proportions of fat and carbohydrate in the diet had little or not effect on growth rate, intestinal wt, and DNA content per centimeter. In a second experiment, 9-d-old sucklings were treated for four consecutive d with either saline or hydrocortisone hemisuccinate at doses assumed to be in the physiologic (0.5 mg/100 g body wt per day) and pharmacologic (2.0 mg/100 g body wt per day) range.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1983

Adaptive response of growing rat small intestine to acute Adriamycin injury.

The response of the intestinal mucosa to Adriamycin (ADR) was studied in the duodenum, jejunum, and ileum of 25-day-old rats. A single injection of ADR resulted in decreases in mucosal DNA per centimeter of length and in sucrase activity, which were proportional to the doses given (2, 5, and 8 mg/kg). ADR at 2 mg/kg had no significant effect on body weight, gut length, epithelial structure, or mucosal protein content per unit length. The morphological modifications occurred mostly in the proximal intestine and consisted of villous atrophy and degenerative changes of villus and crypt cells. A single dose of 5 mg ADR/kg acutely affected the gut. At 48 and 96 h the changes were characterized by marked decreases in mucosal weight, DNA per centimeter, sucrase activity, and villous shortening. At 144 h, the ADR-treated intestine entered a highly proliferative state and showed increased villous height, mucosal weight, and DNA per centimeter. Although villous hyperplasia was observed at 144 and 192 h, the mucosal weight and DNA concentrations did not exceed the corresponding levels in the control. During the period of active epithelial proliferation, sucrase activity remained depressed. We conclude that in the growing rat: (a) the acute intestinal injury of ADR is short-lived, dose dependent, and predominates in the proximal small intestine; (b) the enteric mucosa reacts to cytotoxic injury by excessive proliferation of immature enterocytes; and (c) the hyperplastic response to ADR is confined to the mucosal epithelium.

Animals↗