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Biomedical subjects

R Benamouzig

Publications and source records attributed to R Benamouzig.

At least 55 records · Page 3Linked to original sources
PubMed1996

Putrescine transport in differentiated Caco-2 cells.

OBJECTIVE AND METHODS: To evaluate the putative importance of digestive luminal polyamines, we investigated the role of oxidation in putrescine uptake and transport in differentiated Caco-2 cells grown in monolayer. RESULTS: Our results confirm a putrescine uptake system located both at the apical and basolateral cell membrane. Putrescine is efficiently transported and excreted in the apical-to-basolateral direction. CONCLUSION: These results suggest (i) a diamine oxidase controlled catabolic oxidative excreting pathway and (ii) a paracellular route for putrescine transport. This catabolic route seems to proceed by converting putrescine into gamma-aminobutyraldehyde which is then rapidly excreted from the cell at the basolateral membrane since no gamma-aminobutryraldehyde was detected in the cell. This putative basolateral excreting mechanism is inhibited in the presence of the diamine oxidase inhibitor, aminoguanidine.

Biological Transport, Active↗
PubMed1996

[Mesenteric panniculitis simulating Crohn disease].

Mesenteric panniculitis is a rare disease involving the adipose tissue of the mesentery. We report a case of a 27-year-old woman with mesenteric panniculitis, who presented clinical and radiological features mimicking Crohn's disease. In the outcome, she presented a small bowel perforation, unusual in this pathology, and an annexial involvement. This case reminds us of the role of sepsis and repeated abdominal surgery in relation to the pathogenesis of mesenteric panniculitis. We report the first case of mesenteric panniculitis mimicking Crohn's disease.

Adult↗
PubMed1995

Absence of human papillomavirus DNA detected by polymerase chain reaction in French patients with esophageal carcinoma.

BACKGROUND & AIMS: Recent studies have suggested that esophageal human papillomavirus infection could be a risk factor for esophageal squamous cell carcinoma. The aim of this study was to evaluate the prevalence of human papillomavirus DNA sequences in the esophagus of French patients with esophageal squamous cell carcinoma. METHODS: Multiplex polymerase chain reactions with consensus primers directed to the L1 gene or specific primers for human papillomavirus types 6, 11, 16, 18, 31, and 33 directed to E6 gene (40 cycles followed by restriction mapping of the amplified products) were used to determine the presence of human papillomavirus DNA sequences in esophageal squamous cell carcinoma (n = 75), normal adjacent mucosa (n = 49), and metastatic lymphadenopathies (n = 5). As an internal control, a target located in the embryonic myosin heavy-chain gene was used in each reaction. RESULTS: Human papillomavirus DNA sequences could not be detected in any of the tumoral samples, the normal adjacent mucosa, or the metastatic lymphadenopathies. CONCLUSIONS: Human papillomavirus seems not to be implicated in esophageal carcinogenesis, at least in French patients, because the viral genomes are not associated with esophageal squamous cell carcinomas.

Adult↗
PubMed1995

Exogenous and endogenous nitrogen flow rates and level of protein hydrolysis in the human jejunum after [15N]milk and [15N]yoghurt ingestion.

Milk and yoghurt proteins were 15N-labelled in order to measure the flow rate of exogenous N during digestion in the human intestine. After fasting overnight, sixteen healthy volunteers, each with a naso-jejunal tube, ingested either [15N]milk (n 7) or [15N]yoghurt (n 9). Jejunal samples were collected every 20 min for 4 h. A significant stimulation of endogenous N secretion was observed during the 20-60 min period after yoghurt ingestion and the 20-40 min period after milk ingestion. The endogenous N flows over a 4 h period did not differ between the groups (44.3(SEM 6.5) mmol for milk and 63.5(SEM 5.9) mmol for yoghurt). The flow rates of exogenous N indicated a delayed gastric emptying of the yoghurt N compared with N from milk. The jejunal non-protein N (NPN) flow rate increased significantly after milk and yoghurt ingestion due to an increase in the exogenous NPN flow rate. The NPN fraction of exogenous N ranged between 40 and 80%. The net gastro-jejunal absorption of exogenous N did not differ significantly between milk (56.7(SEM 8.5)%) and yoghurt (50.9(SEM 7)%). The high level of exogenous N hydrolysis is in accordance with the good digestibility of milk products. Fermentation modifies only the gastric emptying rate of N and does not affect the level of diet hydrolysis, the endogenous N stimulation or the digestibility rate.

Adult↗
PubMed1995

15N-labeled immunoglobulins from bovine colostrum are partially resistant to digestion in human intestine.

To evaluate true ileal digestibility of bovine immunoglobulins, seven healthy human adults ingested a 15N-labeled preparation of an immunoglobulin concentrate. After fasting overnight, subjects drank 400 mL of immunoglobulin concentrate (77 mmol), and ileal effluents were collected for 8 h at 20-min intervals using a naso-intestinal intubation technique. In addition to osmolality and pH, the concentrations of exogenous and endogenous nitrogen and ions (Na+, K+, Cl-, Ca2+, Mg2+) in the effluents were measured. Bovine immunoglobulin concentrations (IgG, IgM, IgA) were estimated by a radial immunodiffusion technique. The mean flow rate of the liquid phase was 22.3 +/- 6.1 mL/20 min and did not vary significantly during the collection period. No change was observed for osmolality, pH or Na+, K+ and Cl- concentrations. Two hours after meal ingestion, Ca2+ and Mg2+ concentrations increased significantly (P < 0.05). The recoveries of nitrogen of ingested IgG and IgM still immunologically active were 19 +/- 3% and 19 +/- 4%, respectively. No IgA was detected in the ileum. Mean digestibility of the exogenous nitrogen fraction was 79 +/- 3%. In comparison to literature data, which show that other milk proteins have ileal digestibilities of > 90%, our results demonstrate a lower ileal digestibility of bovine immunoglobulins in humans.

Adult↗
PubMed1995

Digestion patterns of endogenous and different exogenous proteins affect the composition of intestinal effluents in humans.

The purpose of this work was to determine if endogenous luminal proteins are stimulated differently by various dietary proteins and if their digestibility differs from that of dietary proteins. Intestinal effluents were collected from the jejunum of four volunteers who had previously fasted or ingested either casein or soybean proteins. After separating the jejunal digested fraction (nonprotein nitrogen) by dialysis, the protein nitrogen fractions of the effluents and of the protein sources were further hydrolyzed in vitro in a digestion cell with simultaneous dialysis of the digestion by-products. The results indicated a higher (P < 0.05) gastrojejunal absorption of casein (64.5 +/- 2.5%) compared with soybean protein (49.9 +/- 4.1%) in humans. Compared with fasting conditions, protein ingestion increased both the total nitrogen and protein nitrogen of the endogenous nitrogen fraction slightly (P < 0.05) but had no effect on the nonprotein nitrogen fraction. The amino acid profiles of the nonprotein nitrogen in the effluents differed from those of both the protein sources and their mixtures with endogenous secretions. This was attributed to the specific release of amino acids by pancreatic enzymes as measured in vitro. The hydrolysis patterns of amino acids were determined by the structure of food proteins and their interaction with endogenous proteins. Soybean and endogenous nitrogen had equivalent digestibilities when measured in vitro.

Adult↗
PubMed1995

Nitrogen movements in the upper jejunum lumen in humans fed low amounts of casein or beta-lactoglobulin.

OBJECTIVES AND METHODS: To compare the progression of milk proteins in the upper part of the digestive tract, gastro-jejunal nitrogen movements were studied in 6 healthy human volunteers after beta-lactoglobulin and casein ingestion. 400 mL of water (control), purified beta-lactoglobulin (20 g/L) or casein (20 g/L), each adjusted to 25 microCi with 14C-polyethylene glycol, were given per os. Samples were collected in the stomach and 20 cm below the Treitz ligament every 20 min for 2 hours and measured for volume, osmolarity, ions and nitrogen content. RESULTS: The jejunal flow rate peaked in the 0-20 min period following water and beta-lactoglobulin ingestion, and in the 20-40 min period after casein ingestion. The gastric half-emptying time (T1/2 min) of the liquid phase was significantly different (P < 0.05) for water (12.1 +/- 0.8), beta-lactoglobulin (14.5 +/- 3.3) and casein (26.5 +/- 9.3). Before ingestion of the test meals, the basal rate of nitrogen was 9.14 +/- 4.09 mmol/h in the jejunum. The total nitrogen content in the jejunum peaked significantly in the 0-20 min period after beta-lactoglobulin ingestion and the 20-40 min period after casein ingestion. The apparent gastro-jejunal protein absorption values were 63% for casein and 66% for beta-lactoglobulin in the 120 min period. CONCLUSIONS: These results show that beta-lactoglobulin and casein behave differently in the upper part of the digestive tract due to different gastric emptying rates.

Adult↗
PubMed1994

True exogenous and endogenous nitrogen fractions in the human jejunum after ingestion of small amounts of 15N-labeled casein.

The purpose of this work was to determine exogenous and endogenous contributions to the overall nitrogen flux in the upper jejunum in humans. After the ingestion of water or 8 g of [15N]casein, the behavior of gastro-jejunal nitrogen and electrolyte (Na+, K+, Cl-) movements were studied in seven volunteers using the "slow marker" perfusion technique. The jejunal flow-rate of the chyme peaked during 0-20 min and 20-40 min periods following water and casein ingestion, respectively. Osmolarity, Cl- and Na+ concentrations decreased significantly (P < 0.05) during the first 20 min following meal ingestion and returned to the basal levels in the 20-60 min period. The gastric half-emptying times (min) of the liquid phase differed significantly (P < 0.05) for water (7.9 +/- 0.4) and casein (21.4 +/- 9.1). The basal flow rate of endogenous nitrogen was 9 +/- 3.3 mmol/h in the jejunum. After casein ingestion, the total nitrogen content reached maximum values in the 20-40 min period and then progressively returned to the initial level. The gastro-jejunal casein absorption was 58% and the remaining amount of casein in the jejunum was degraded more than 80% to alcohol-soluble compounds. After the ingestion of a low amount of casein no significant increase in the endogenous nitrogen fraction was observed. The 15N-dilution technique is an appropriate method in humans for the direct measurement of endogenous and exogenous contributions to the intestinal nitrogen fraction.

Adult↗
PubMed1992

Human papillomavirus infection in esophageal squamous-cell carcinoma in western countries.

Recent studies have suggested that esophageal HPV infection could be a risk factor for esophageal squamous-cell carcinoma. The aims of our study were to assess the presence of HPV esophageal infection among French patients with esophageal squamous-cell carcinoma and to compare the prevalence of this infection among control patients exposed to similar known risk factors (alcohol and tobacco) and among non-exposed control patients. All patients had the following investigations: serum immunoglobulin level, T-lymphocyte subsets, cutaneous anergy test and endoscopy with biopsies from tumoral and normal areas. Three different methods were used for HPV-infection diagnosis: histological score, in situ hybridization intended for detection of HPV types 6, 11, 16, 18, 31 and 33, and dot blot intended for detection of HPV types 6/11 and 16/18. Five out of 12 patients with esophageal carcinoma had HPV esophageal infection. This infection did not result from impaired immune status. The most frequently observed types are HPV 16/18. None out of 17 exposed controls and only 1 out of 7 nonexposed controls had HPV esophageal infection (p less than 0.01). HPV infection may be implicated in the development of esophageal squamous-cell carcinoma in association with known risk factors.

Age Factors↗