Milton M. Weiser

Relevance of major stress events as an indicator of disease activity prevalence in inflammatory bowel disease.

The impact of psychological stress in recurrence of inflammatory bowel disease (IBD) is unclear. Why some patients with ulcerative colitis (UC) or Crohns disease (CD) have unrelenting relapses whereas other IBD patients experience long periods of quiescent disease remains an enigma. The authors examined the risk of exposure to major stress events in clinical episodes of IBD. They followed up on 124 persons in a prospective study that monitored behavioral and biological characteristics for a period of 6 months. Stress-exposed subjects demonstrated increased risk of clinical episodes of disease when compared with unexposed subjects (RR = 2.6, 95% CI: 1.3-4.9). Elevated effect measures were highest for the domain of health-related stress (RR = 3.8, 95% CI: 1.5-9.9). In the multiple regression analysis, major stress events remained the most significant indicator of disease activity in the presence of the covariables considered. Only 7% of the variation in disease activity was uniquely attributed to stress. Baseline activity was the other notable indicator of subsequent disease activity in the study sample. All variables considered together explained 52% of the variance observed and implicated factors of potential clinical importance in monitoring recurrence of the disease.

The effect of vitamin D on rat intestinal plasma membrane Ca-pump mRNA

The effects of vitamin D on steady-state levels of rat intestinal Ca-pump mRNA were examined in RNA extracted from isolated cell fractions of the crypt-to-villus gradient of differentiation. Northern blots revealed three different size mRNAs. Vitamin D deficient animals showed a decrease in these Ca-pump mRNAs, which increased markedly after 1,25-(OH)2D3 repletion, particularly for the villus cell. The data suggest that one of the effects of 1,25-(OH)2D3 may be to modulate enterocyte Ca-pump mRNA and that this effect is partly dependent on the stage of cell differentiation.

Lag time between stress events and risk of recurrent episodes of inflammatory bowel disease.

We followed a cohort of 124 subjects with a history of inflammatory bowel disease to ascertain risk estimates for clinically active disease associated with exposure to recent stress events. We calculated risk estimates for three lag models (-1, 0, + 1 month). The data indicated a strong association between stress exposures and new clinical episodes of disease (RR = 2.9, 95% Cl: 2.0-4.1), most apparent in the immediate period (lag = 0). Risk estimates were also elevated for extended episodes of disease in subjects under stress compared with unexposed subjects. These results underscore the importance of monitoring stress exposures in prevention and treatment of recurrent disease.

Intestinal cell membranes

Publisher Summary This chapter discusses the particular properties of the intestine that are important to studies of the plasmalemma of the enterocyte. The chapter also reviews methods for preparing enterocyte membranes along with their particular advantages and problems. The properties and characteristics that distinguish the isolated membrane preparations are presented. In addition, the chapter presents comparisons of the studies of enterocyte membrane synthesis to those with cells in tissue culture or other tissues. The studies of intestinal cell membranes, their characteristics, and synthesis have contributed significantly to an understanding of the plasmalemmal organization of a fixed tissue cell. The role of Golgi and Golgi-derived vesicles in plasmalemmal synthesis and turnover is well-recognized. The intestine has been shown to be a readily accessible tissue, uniquely suited to the study of the molecular biology of membranes. The two unique features of the intestine include the continuous gradient of differentiation with loss of cells along the crypt-villus axis, and the continuous changes in organization and function along the aboral gradient. The presence of pancreatic and biliary secretions or the active hydrolytic enzyme activities inherent in the mature enterocyte microvillus membrane also contribute to the unusual properties attributed to the intestine.

Vasoactive intestinal peptide as a laboratory supplement to clinical activity index in inflammatory bowel disease

Circulating levels of vasoactive intestinal peptide (VIP) in plasma were measured in gauging activity in inflammatory bowel disease (IBD). One hundred-fifteen adult IBD patients were studied cross-sectionally and prospectively, 48 with ulcerative colitis (UC) and 67 with Crohns disease (CD). Sequential samples of plasma were assayed for VIP by specific radioimmunoassay. Sixty males and 55 females, ranging in age from 22 to 76 years were studied over six months. The results revealed a strong, positive association between VIP levels and clinical activity, both at baseline (r=0.38, P<0.001) and follow-up (r=.41, P<0.001). The ability of the VIP immunoassay to gauge clinical activity was also evaluated where VIP concentrations above 30 pg/ml were defined as abnormal. At baseline, sensitivity (specificity) was found to be 81% (55%). The predictive value of a positive (negative) test was 57% (80%). These estimates did not differ at follow-up. Examination of paired plasma samples from intermittently active patients revealed nearly twofold increases (P<0.05) in VIP concentration during active periods of disease. The data suggest that plasma VIP levels may be a valuable laboratory parameter in gauging activity in inflammatory bowel disease.

Laminin receptor expression in rat intestine and liver during development and differentiation

BACKGROUND/AIMS Studies have identified a 67-kilodalton high-affinity laminin receptor (LR) whose expression has also been related to development, differentiation, and neoplastic transformation. The relationship of the 67-kilodalton LR to hepatic and enterocyte development and to enterocyte differentiation was investigated. METHODS LR messenger RNA (mRNA) was identified using a complementary DNA isolated from a rat crypt cell library. LR and integrin (alpha 6, beta 1, and beta 4) expression by rat intestinal crypt cells was compared with that of the more differentiated villus cells using Northern blotting. Developmental differences in LR expression were studied in fetal and neonatal rats. The pattern of LR expression in fetal and adult rat intestines was examined further by in situ hybridization. RESULTS LR mRNA levels were highest in fetal liver and intestine and adult rat crypt cells. LR mRNA levels were 9-10 times greater in crypt than in villus cells. Integrin subunit expression differed little between crypt and villus cells. Nascent transcription studies showed that the proportion of newly transcribed LR mRNA per total RNA synthesized was similar for crypt and villus cells, suggesting posttranscriptional control of LR mRNA levels in villus cells. CONCLUSIONS Increased LR mRNA expression is a feature of the fetal intestine and of the undifferentiated, mitotically active crypt cells.

Co-purification of soluble human galactosyltransferase and immunoglobulins.

Abstract Preparations of human malignant effusion galactosyltransferase activity purified according to previously published techniques using enzyme-specific affinity chromatography consistently produced antibodies directed toward immunoglobulins with no detectable antigalactosyltransferase. Double immunodiffusion analysis of the antigen showed the presence of both IgG and IgA. Affinity chromatography with anti-human IgG-Sepharose and anti-human serum-Sepharose resulted in a 48,000-fold purification of galactosyltransferase activity with no detectable IgG by radioimmunoassay. Immunization of rabbits with this preparation produced antibodies directed against galactosyltransferase activity and minimal anti-Ig. The persistence of immunoglobulins during the purification of soluble galactosyltransferase activity through two enzyme-specific affinity chromatographic steps suggests an association of immunoglobulins with galactosyltransferase activity.

Colonic cancer cell (HT29) adhesion to laminin is altered by differentiation : adhesion may involve galactosyltransferase

The effects of cell differentiation on cell adhesion to laminin were studied using the human colon tumor cell line, HT29. HT29 cells were induced to differentiate either by glucose deprivation (HT29glc- vs HT29glc+) or by 2 mM butyrate (HT29glc-+B+). Adhesion was assayed after incubating cell suspensions in microtiter wells previously coated with laminin or other substrates. HT29glc+ cells adhered preferentially to laminin over BSA, fibronectin, and ovalbumin. The adhesion to laminin was greater than 50% of maximum within 15 min. HT29glc- cell adhesion to laminin was consistently lower than that for HT29glc+ or HT29glc+B+ cells. alpha-Lactalbumin (ALA), a modifier of galactosyltransferase (GT) substrate specificity, caused a significant reduction (greater than 50%) in HT29glc+ cell adhesion to laminin when ALA was added to the adhesion incubation mixture. Addition of glucose+ALA to the suspension restored adhesion to laminin. Ovalbumin, a GT substrate, increased adhesion of HT29glc+ and HT29glc- cells to laminin, but lactose, a GT product, did not. The data show that undifferentiated HT29 cells adhere preferentially to laminin over fibronectin and collagen IV and that differentiation of HT29 cells reduces adhesion to laminin. In addition, the data imply that cell adhesion to laminin may be mediated by factors that also modify galactosyltransferase activity.

Udp-galactose inhibition of balb/3t12-3 cell growth. Requirement for medium galactosyltransferase activity.

Abstract Incubation of BALB/3T12-3 cells with uridine diphosphate galactose (UDP-gal) resulted in a concentration-dependent inhibition of cell growth when cells were cultured in calf serum-supplemented Dulbeccos modified Eagle medium (CS-DMEM). Cell growth was completely inhibited by 5 mM UDP-gal with an ID 50 of 0.75 mM. This inhibitory effect was reversible. Other nucleotide-sugars, as well as galactose, glucose, and galactose-1-phosphate had no effect on cell growth. UDP-gal had no effect on cell growth when cells were cultured in heat-inactivated calf serum containing DMEM (HICS-DMEM) suggesting that a serum enzyme activity was responsible for the inhibition observed in CS-DMEM. No significant difference could be detected by descending chromatography in the degradation of UDP-gal during 96 h of incubation in CS-DMEM and in HICS-DMEM. Furthermore, the potential breakdown products of UDP-gal had no effect on cell growth when added directly to 3T12 cultures. When cells were incubated with 5 mM UDP-gal+5 mM CDP-choline (a potent inhibitor of pyrophosphatase activity), complete inhibition of cell growth was still observed. However, if cells were incubated with 5 mM UDP-gal+UDP (which inhibited calf serum galactosyltransferase activity), no inhibition of cell growth was observed over that found for UDP alone, suggesting that galactosyltransferase and not pyrophosphatase activity mediated the effect of UDP-gal on cell growth. A direct effect of UDP-gal on cells was suggested by ( a ) normal growth of cells in UDP-gal-conditioned medium (preincubated with UDP-gal for 24 h followed by dialysis to remove UDP-gal); ( b ) 3-fold greater incorporation of [ 3 H]galactose from UDP-[ 3 H]gal into cells grown in CS-DMEM than in HICS-DMEM. These studies suggest that the inhibition of 3T12 cell growth by exogenous UDP-gal may be due to alteration of cell surface glycoconjugates by extracellular galactosyltransferase activity.

Intestinal basolateral membrane Ca-ATPase activity with properties distinct from those of the Ca-pump

The Ca-pump in rat intestinal basolateral membranes had been studied previously as vesicular ATP-dependent Ca-uptake. In the present studies, Ca-stimulated ATP hydrolysis (Ca-ATPase activity) was measured and found to differ from the Ca-pump in having higher activity and being insensitive to vanadate. Whereas the pump was specific for ATP, hydrolytic activity was found with ATP, GTP or ADP but not with AMP or p-nitro-phenyl-phosphate. In contrast to Ca-pump activity, Ca-ATPase activities were similar for different intestinal segments, for duodenal villus/crypt cell-fractions and for vitamin D-deficient animals. Thus, as usually measured, intestinal basolateral membrane Ca-ATPase activity is not equivalent to the Ca-pump.