Warren L. Beeken

Calcium Absorption in Crohn's Disease

Calcium absorption and endogenous loss of calcium were measured in a group of patients with Crohns disease, using a simultaneous metabolic balance and calcium isotope regimen. Calcium malabsorption resulting in negative calcium balance was found in only 4 of 31 patients with Crohns disease. No elevation of endogenous fecal calcium or total secreted intestinal calcium was observed in 10 patients studied, regardless of the level of net or true calcium absorption. Correlation between calcium balance and serum protein loss was observed, but no association was noted with intestinal fat excretion, d-xylose absorption, bacterial colonization of the jejunum, or glucocorticosteroid therapy. The results indicate that in this group of patients with Crohns disease involving different areas of the intestine, calcium malabsorption occurred infrequently and that the levels of calcium excretion correlated best with enteric protein loss.

Pneumatosis intestinalis in patients with Crohn's disease

The prevalence, predictors, and significance of pneumatosis were determined in 50 patients with Crohns disease who had abdominal CT scans to rule out abscess. The presence or absence of six CT descriptors and 17 clinical descriptors was documented. CT scans of a control group of 50 subjects without inflammatory bowel disease were also examined. Data was analyzed by two-sample t tests and Fishers exact test. Pneumatosis was found in six of 50 patients with Crohns disease and in none of the controls. Corticosteroid treatment was the single clinical variable relating significantly (P=0.025) to pneumatosis, although trends toward absence of resection, short duration of illness, and more severe anemia were also evident in this group. This study suggests that the presence of pneumatosis alone does not dictate a specific course of treatment, but when pneumatosis is present, careful monitoring is required and therapy is based on the overall clinical picture.

Comparative Viabilities of Rat Intestinal Epithelial Cells Prepared by Mechanical, Enzymatic and Chelating Methods

Mechanical, enzymatic and chelating methods for isolating rat intestinal epithelial cells were compared to determine the best technique for obtaining high yields of viable cells. The mechanical techniques resulted in consistently poor viability compared with the other methods. There was excellent agreement between viability determinations made by trypan blue exclusion and by cytofluorochromasia. Incubation with EDTA, citrate and dithiothreitol, combined with mechanical extrusion of dissociated cells provided the highest yields of viable cells in these studies.

The role of urinary indican as a predictor of bacterial colonization in the human jejunum.

To evaluate the role of urinary indican excretion and several common absorptive tests as predictors of bacterial colonization in the human jejunum, we analyzed the relationship between indican excretion and quantitative jejunal cultures, tryptophan absorption, enteric protein loss, fecal nitrogen excretion, D-xylose and lactose tolerance tests, and B12 and fat absorption in 40 subjects. Indican excretion correlated poorly with jejunal colony counts (r=0.22). Neither tryptophan load or absorption, nor nitrogen excretion were related to indicanuria, but there was a modest correlation between enteric protein loss and urinary indican values (r=0.54). Lactose tolerance tests and D-xylose, B12 and fat absorption showed no predictive value for identifying patients with high colony counts. Compared to quantitative small bowel culture, none of the tests studied provided suitable methods for screening for bacterial contamination of the human jejunum.

Comparative studies of mononuclear phagocyte function in patients with Crohn's disease and colon neoplasms.

Phagocytosis and cellular cytotoxicity by mononuclear phagocytes of blood and intestinal mucosa were studied in patients with Crohns disease and large bowel neoplasms. Antibody coated sheep erythrocytes were used for phagocytic assays and cellular cytotoxicity in vitro was measured by 24 hour isotope release from 75Selenium methionine-labelled RPMI 4788 human cancer cell cultures in the presence of mononuclear phagocyte-enriched effector populations. The mean percent of mononuclear phagocytes in Ficoll-Hypaque purified mononuclear cell suspensions of blood of healthy controls was 25.9 compared with 44.6 in patients with Crohns disease, 45.6 in patients with colon neoplasms and 11.6 in intestinal mucosa. Phagocytic indices were similar in all groups, but the phagocytic capacity of mucosal macrophages was twice that of blood monocytes. Mean cytotoxicity of monocytes of patients with Crohns disease was 12.8% compared with 22.9% for monocytes from normal controls, and 29.4% for patients with colon tumours. Mean cytotoxicity by mucosal macrophages was 18.0% compared with 13.2% by mucosal lymphocyte populations. Exposure of monocytes of Crohns disease patients to bacterial lipopolysaccharide modestly increased cytotoxicity, but exposure did not alter phagocytosis by monocytes of patients or controls. The results indicate that monocytes of patients with Crohns disease exhibit subnormal in vitro cytotoxicity. Mucosal macrophages from patients with various diseases show enhanced phagocytosis compared with blood monocytes, and they can mediate cellular cytotoxicity in vitro.

A prospective study of the course of Crohn's disease

To better define the course of Crohns disease, certain clinical, laboratory, and radiological features were studied prospectively in a representative group of 25 patients at intervals of up to 77 months. Eleven variables of potential use in assessing the course were analyzed for clinician preference, and the statistical relationship of one variable, the Crohns disease activity index, to the other 10 was determined. Modest improvement was documented in three clinical variables, as well as in anemia, serum albumin, intestinal protein loss, and radiological extent of disease. Variables most frequently ranked high as reflections of the course of Crohns disease were hematocrit and extent of disease, followed by body weight, stools per day, B12 absorption, serum albumin, and intestinal protein loss. The highest intervariable correlation was between improvement in protein loss and decrease in radiological extent (r=0.75).

In vitro cellular cytotoxicity for a human colon cancer cell line by mucosal mononuclear cells of patients with colon cancer and other disorders

In vitro cellular cytotoxicity of mononuclear cells of intestinal mucosa and peripheral blood for a colon cancer cell target was measured in patients with colon cancer and other disorders requiring resection. Four‐ and 24‐hour cytotoxicity assays were conducted using selenium 75 (75Se)‐labeled RPMI‐4788 human colon cancer target cells grown in culture. In the cancer group mean cytotoxicity was 30.4% at 24 hours for peripheral blood effectors and 8.0% for effectors from normal mucosa. Values in patients with Crohns disease were 10.4% for blood and 17.2% for effectors from normal mucosa, and 13.6% and 18.5%, respectively, for blood and abnormal mucosa. Values in patients with other diseases were 25% for blood and 14.7% for mucosa. Mean cytotoxicity at 4 hours did not exceed 6.4% for any group, and assays in autologous serum gave results similar to tests in calf serum. In additional studies, K 562 chronic leukemia cells were somewhat more sensitive to lysis than RPMI‐4788 by blood mononuclear cells, but there was no lysis of K 562 by mucosal populations that were cytotoxic for RPMI‐4788. There was no competitive inhibition by either target cell for the other. It was concluded that 75Se RPMI‐4788 colon cancer cells are suitable targets for evaluating in vitro cytotoxicity by intestinal mucosal cells and that mucosal cytotoxicity in patients with colon cancer is depressed compared to cytotoxicity by peripheral blood effectors.

Scanning electron microscopy of rectal mucosa in Crohn's disease

Rectal biopsies from healthy control subjects, and from patients with Crohns disease whose rectal mucosa appeared normal by sigmoidoscopy and light microscopy, were examined by scanning electron microscopy. Appearances within both groups were quite variable, and no clear differences between the groups could be distinguished.

Case report: intestinal clearance of calcium and protein in Waldenstrom's macroglobulinemia.

A 63-year-old man with Waldenstroms macroglobulinemia had severe steatorrhea, marked protein-losing enteropathy, and excessive endogenous fecal calcium clearance. The malabsorption and protein loss resulted in weight loss and hypoalbuminemia. In contrast, the striking enteric calcium loss was completely compensated by an increase in calcium absorption resulting in a positive calcium balance.

140-MDa plasmids of Escherichia coli and Shigella flexneri 5 do not influence phagocytosis.

Enteroinvasive Escherichia coli (EIEC) and Shigella flexneri possessing a 140-megadalton (MDa) plasmid are capable of invading intestinal epithelial cells and causing dysentery. To determine if this plasmid affected phagocytosis of the organisms by leukocytes, we studied the in vitro phagocytosis of isogenic pairs of EIEC and S. flexneri 5 which differed only in the presence or absence of the 140-MDa plasmid. In addition five EIEC strains containing 140-MDa plasmids as well as one non-enteroinvasive E. coli strain possessing a 120-MDa plasmid were studied. The 140-MDa plasmid did not affect phagocytosis of these bacteria by normal human blood neutrophils or monocytes.