Daniel Balas

Exocrine pancreatic secretion in the elderly

SummaryIn order to evaluate impairment of exocrine pancreatic function during aging, 27 subjects (mean age: 36 years±7.8) and 28 subjects (mean age: 72 years±3.2), with no clinical or radiological evidence of digestive disease, were selected. Duodenal aspirates over a 60 min period were obtained during continuous IV infusion of secretin (0.5 U/kg/h) and caerulein (75 ng/kg/h). Bicarbonate, lipase, chymotrypsin, amylase concentrations and output were measured. Bicarbonate, lipase, chymotrypsin concentrations in the aged group were significantly reduced by 17%, 15% and 23% respectively (P<0.05) as compared with those in the young group. In addition, a significant reduction of approximately 45% in bicarbonate and enzyme output levels was observed. This study provides strong evidence for a marked functional involution of the exocrine pancreatic secretion during aging. The potential consequences of this phenomenon on the nutritional status in the elderly are discussed.

Expression of REG Protein During Cell Growth and Differentiation of Two Human Colon Carcinoma Cell Lines

We localized REG protein in Paneth cells and nonmature columnar cells of the human small intestinal crypts and speculated that this protein was associated with growth and/or differentiation. The aim of this study was to determine whether REG protein is present in two human colon cancer cell lines that exhibit enterocytic differentiation after confluence and to investigate changes in the level of its expression during growth and differentiation. Results were compared to those obtained on cells that remain undifferentiated. Western immunoblotting and immunofluorescence demonstrated the presence of REG protein in the three cell lines. With the antisera against human REG protein, the staining was diffusely spread throughout the cytoplasm at Day 2, and after Days 3-4 it appeared to have migrated to cell boundaries. After confluence, we observed only a punctate staining array along cell boundaries, which disappeared at Day 15. REG mRNA expression was demonstrated by RTPCR and REG mRNA hybridization until Day 13, but not after, in the three cell types. REG protein may be involved in cellular junctions. Its presence appears to be associated with the cell growth period and the protein must be downregulated when growth is achieved and differentiation is induced.

Diet Supplemented with Yoghurt or Milk Fermented by Lactobacillus casei DN-114 001 Stimulates Growth and Brush-Border Enzyme Activities in Mouse Small Intestine

The nutritional benefits of lactic acid bacteria in fermented dairy products have been well documented, especially in terms of weight gain and feed efficiency, but not in terms of small intestine adaptation. The effects of a diet supplemented (30% wt/wt) with milk fermented either by Lactobacillus casei DN-114 001 or yoghurt for 3 or 15 days were investigated in the small intestine of mice by morphometry, kinetic analysis and determination of brush-border enzyme activities. Results were compared with those obtained with standard or milk isocaloric diets. Cell proliferation and villous area were significantly increased in the proximal intestine of mice fed the fermented-milk-supplemented diets for 3 days and were associated with hypertrophy and hyperplasia of Paneth and goblet cells. Lactase-specific activity was increased by fermented-milk diets at days 3 and 15, whereas there was no variation in maltase-specific activity. Alkaline phosphatase-specific activity was increased after 3 days of the three tested diets in the whole intestine, and after 15 days in the proximal intestine. Aminopeptidase activity was increased in the distal part of the intestine after 3 days of the 3 diets. Our findings suggest that diets supplemented with fermented milks have a positive effect on the trophicity of the mucosa in the small intestine of mice.

Immunocytochemical demonstration of a pancreatic secretory protein of unknown function in human duodenum

We have previously isolated from human pancreatic juice a secretory glycoprotein of 19 KD (P19), devoid of known enzymatic activity. P19 gave by proteolysis a protein of 14 KD (P14), at first named protein X and also called pancreatic thread protein or pancreatic stone protein. Specific rabbit immunosera prepared against P19 and P14 were applied to localize these proteins in human small intestine. By comparison, antibodies directed against some human pancreatic enzymes (amylase, lipase, chymotrypsin, trypsinogen 1, trypsinogen 2, and trypsin 1) were also tested. Positive immunoreactivity was observed on Paneth cells with antisera directed against trypsinogens, trypsin 1, and P19-related proteins. In addition, antisera directed against P19-related proteins stained the columnar cells located in the crypts of Lieberkühn. These original findings are a further indication of the resemblance between Paneth and pancreatic acinar cells but show that their functional analogy is only partial. On the other hand, the presence of P19-related proteins on non-mature columnar cells suggests that this differential distribution is a consequence of differentiation.

Gastric lipase in alcoholic pancreatitis

Abstract The aims of this study were to evaluate the amount of gastric lipase secreted by the stomach in normal adults and to elucidate a possible adaptative secretion of this enzyme in response to pancreatic insufficiency secondary to alcoholic chronic pancreatitis. Forty-one subjects underwent a gastric intubation. Pentagastrin (6 μg · kg −1 · h −1 IV) significantly increased gastric lipase concentration and output. Stimulated gastric lipase output in seven normal subjects was 12,598 ± 2036 U/h (by using tributyrin as substrate). Outputs where higher ( P

Histological variations of the duodenal mucosa in chronic human pancreatitis.

From 16 volunteers with chronic pancreatitis and 36 healthy subjects duodenal biopsies were taken 15–20 cm beyond the papilla of Vater. Several morphometric parameters were calculated. The main results show: a significant decrease of villous area and height but not of the number of intestinal villi; a significant increase of Paneth cells; and a slight decrease in the number of glandular mitoses. This study suggests in man, a possible relationship between exocrine pancreatic secretion and the intestinal mucosa and a trophic action of pancreatic juice on the proliferation and the differentiation of the intestinal mucosa.

Histological Variations of Jejunal and Ileal Mucosa on Days 8 and 15 after Hypophysectomy in Rat: Morphometrical Analysis in Light and Electron Microscopy

Variations of the intestinal mucosa were studied in male adult Wistar rats on day 8 and day 15 after hypophysectomy. All results were compared with those obtained in pair-fed control rats. Morphologic

Long-Term Effect of Somatostatin 14 on Mouse Stomach, Antrum, Intestine and Exocrine Pancreas

Mice were injected 3 times a day for 12 days with 8 micrograms/kg of somatostatin 14 which caused a hypoplasia of parietal and goblet cells, a hypotrophy and hypofunctionality of pancreatic acinar cells with a decrease in lipase and chymotrypsin activities, a decrease in the secretory fuction of the Brunner gland and in the number of dark granules of G cells. Neither villous and microvillous areas nor brush border hydrolase activities were affected. The number of peptic cells and Paneth cells increase as the level of pepsin and lysozyme. Mice were injected 4 times per hour with 2 micrograms/kg of somatostatin. 2 h after the first injection of somatostatin and 90 min after a single injection of tritiated thymidine, fundic, antral, jejunal and ileal labelling indexes strongly decrease (maximal effect in ileum). The inhibitory effect of somatostatin on the digestive epithelial cell proliferation compared to its long-term action only directed on specific cell types evokes probable compensatory mechanisms induced to maintain the equilibrium of the digestive epithelia.

A Cyto-physiological Study of the G-cell Secretory Cycle in the Antrum Mucosa of the Hamster and of the Rat

The secretory cycle of the antral G cell in the golden hamster and in the Wistar rat has been investigated, using classical techniques of optical and electron microscopy associated with special methods (such as goniometry, densitometry, immunohistology, morphometry) and with radioimmunoassay for gastrin. This paper confirms the secretory cycle of the G cell after refeeding. It clarifies the nature of granule polymorphism and suggests a particular mechanism of emiocytosis with sequential granule fusion. Furthermore, our investigations show some dissociations between the G cell, the parietal cycle, and the seric immunoreactive gastrin in the late phase of the secretory cycle (2 to 6 h after refeeding).

Pancreatic trypsinogen I expression during cell growth and differentiation of two human colon carcinoma cells

Pancreatic trypsin has been found to induce tight junction or dome formation in some colon cancer cell lines (HT-29, Caco-2), and a tumor-associated trypsinogen, trypsinogen type II, has been isolated from another colon cancer cell line (COLO 205). We have tried to determine if trypsinogen is present and how its expression varies during cell culture in HT-29 Glc+/- and Caco-2 cells, which exhibit enterocytic differentiation, and in HT-29 Glc+ cells, which never differentiate. Trypsinogen mRNA presence and expression were demonstrated in these cells by mRNA hybridization, RT-PCR, cytoimmunofluorescence, Western immunoblot analysis, and gel filtration. Trypsinogen was found to be trypsinogen type I and was mainly in zymogen form in culture media. Differentiating cells exhibited variations in trypsinogen I expression, but cells that remained undifferentiated did not. In the differentiated cells, a high and transient peak in trypsinogen I expression was observed during the first steps of differentiation.Pancreatic trypsin has been found to induce tight junction or dome formation in some colon cancer cell lines (HT-29, Caco-2), and a tumor-associated trypsinogen, trypsinogen type II, has been isolated from another colon cancer cell line (COLO 205). We have tried to determine if trypsinogen is present and how its expression varies during cell culture in HT-29 Glc+/- and Caco-2 cells, which exhibit enterocytic differentiation, and in HT-29 Glc+ cells, which never differentiate. Trypsinogen mRNA presence and expression were demonstrated in these cells by mRNA hybridization, RT-PCR, cytoimmunofluorescence, Western immunoblot analysis, and gel filtration. Trypsinogen was found to be trypsinogen type I and was mainly in zymogen form in culture media. Differentiating cells exhibited variations in trypsinogen I expression, but cells that remained undifferentiated did not. In the differentiated cells, a high and transient peak in trypsinogen I expression was observed during the first steps of differentiation.