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C R Kapadia

Publications and source records attributed to C R Kapadia.

At least 19 recordsLinked to original sources
PubMed1990

Laser-induced fluorescence spectroscopy of human colonic mucosa. Detection of adenomatous transformation.

To evaluate the potential of laser-induced fluorescence spectroscopy for the detection of premalignant lesions of the gastrointestinal tract, the hypothesis that adenomatous transformation of colonic mucosa results in an alteration of laser-induced fluorescence that enables its differentiation from normal or hyperplastic tissue was tested. A fiberoptic catheter coupled to a helium-cadmium laser (325 nm) and an optical multichannel analyzer were used to obtain fluorescence spectra (350-600 nm) from 35 normal colonic specimens and 35 resected adenomatous polyps. A score based on six wavelengths was derived by stepwise multivariate linear regression analysis of the spectra. The mean score (+/- SEM) was + 0.86 +/- 0.06 for normal mucosa and -0.86 +/- 0.06 for adenomatous polyps (P less than 0.001). Spectra from an additional 34 normal specimens, 16 adenomatous polyps, and 16 hyperplastic polyps were prospectively classified with accuracies of 100%, 100%, and 94%, respectively. The mean score for hyperplastic polyps was significantly different from adenomatous (P less than 0.001) but not from normal tissue. Thus, quantitative analysis of fluorescence spectra enables the detection of adenomatous transformation in colonic mucosa.

Adenomatous Polyposis Coli↗
PubMed1990

Recurrent hemorrhage from an invaginated Meckel's diverticulum in a 78-year-old man.

Complications arising from Meckel's diverticulum are uncommon in adults and are seldom, if ever, seen in the elderly. When they do occur in adults, intestinal obstruction or inflammation is the usual mode of presentation, hemorrhage being much less common. The patient described in this case report was 78 yr old, presented initially with iron deficiency anemia and, later, developed severe acute hemorrhage. The cause of the hemorrhage was ulceration at the tip of an invaginated Meckel's diverticulum. The ulceration was not peptic in origin, as is usually the case in similar presentations in children, no ectopic oxyntic mucosa being detected in the diverticulum of our patient. In previous reports, invaginated Meckel's diverticula have always been accompanied by intussusception, and abdominal pain has been an important part of the symptom complex in such patients. Our patient had no abdominal pain, and no intussusception was noted at surgery. This case emphasizes the need for considering a Meckel's diverticulum as the source of acute or chronic hemorrhage, irrespective of the patient's age. The utility of radionuclide blood pool imaging in arriving at a diagnosis in these cases is discussed.

Aged↗
PubMed1988

Active absorption of vitamin B12 and conjugated bile salts by guinea pig ileum occurs in villous and not crypt cells.

We isolated highly enriched fractions of villous and crypt cells from guinea pig intestine to determine whether this preparation provided a suitable model for comparing the transport of cobalamin and conjugated bile salts by these cell populations. The uptake of [57Co] cyanocobalamin by ileal villous cells was 30-fold greater when incubated with cobalamin bound to intrinsic factor than with free cobalamin. Intrinsic factor-mediated uptake of cobalamin could not be demonstrated using ileal crypt or jejunal villous or crypt cells. When incubated with [3H] taurocholate, the uptake by ileal villous cells was significantly greater than by ileal crypt or jejunal villous cells. These results indicate the suitability of using isolated guinea pig villous and crypt cells to examine transport processes of molecules that involve specialized mechanisms. The results also demonstrate that the undifferentiated crypt cell lacks specific transport processes necessary for the active absorption of cobalamin and taurocholate.

Animals↗
PubMed1986

Ultrastructure and localization of substance P and met-enkephalin immunoreactivity in the human fetal gastric antrum.

The ultrastructural localization and relations of substance P- and met-enkephalin-labeled neuronal structures were examined in the wall of the human gastric antrum during early fetal life. By 14-16 weeks of gestation, clearly discernable neural plexuses and a well developed external muscle coat were present. In the submucous coat, neural plexuses varied from immature forms consisting of 1-4 neurites partially enveloped by Schwann cell processes to more mature plexuses where neurons were completely enclosed by Schwann cell processes. Neuronal profiles with substance P- and met-enkephalin-like immunoreactivities were observed in the submucous plexus. In the myenteric plexus met-enkephalin-like immunoreactivity was seen within cell bodies and neurites. By contrast, although substance P-like immunoreactivity was observed in neurites in the myenteric plexus, no substance P-labeled somata could be identified. Unlabeled terminals were seen in contact with both unlabeled dendrites and met-enkephalinergic neurons. An increase in electron density was observed at the sites of contact. These structures probably represent early stages in the development of synaptic specializations. In addition, met-enkephalin-labeled varicosities were seen in apposition to smooth muscle cells of the circular muscle coat. This suggests that antral smooth muscle cells are directly innervated by met-enkephalin neurons.

Embryonic and Fetal Development↗
PubMed1986

Branched chain amino acid uptake and muscle free amino acid concentrations predict postoperative muscle nitrogen balance.

Amino acid solutions rich in branched chain amino acids (BCAA) are commonly utilized both clinically and in experimental protocols in an attempt to reduce skeletal muscle and whole body protein catabolism. To investigate the effectiveness of BCAA infusion, amino acid formulas containing varying concentrations of BCAA were given during operation in this study to three groups of dogs undergoing a standard laparotomy and retroperitoneal dissection. A fourth group was given saline alone. With the use of previously described hindquarter flux techniques, individual and total amino acid nitrogen exchange rates were measured and utilized in estimating skeletal muscle protein catabolism. Intracellular free amino acid concentrations were measured in percutaneous muscle biopsy samples. Although there was no relationship with the rate of BCAA infusion, there was a significant correlation between the rate of BCAA uptake by muscle and diminished total nitrogen release from hindquarter skeletal muscle after operation. There was also a significant relationship between muscle nitrogen balance and the postoperative change in the muscle concentration of either total amino acids or the single amino acid glutamine. When combined in a single equation, BCAA uptake and the change in muscle free amino acid concentration predict skeletal muscle nitrogen release with an r = 0.86. Thus, the rate of BCAA uptake and the free glutamine or total amino acid concentration in muscle appear to be independent predictors of muscle nitrogen balance. The nitrogen-sparing effect of BCAA in skeletal muscle is unrelated to infusion concentration or rate of infusion.

Amino Acids↗
PubMed1985

Disorders of cobalamin (vitamin B12) absorption and transport.

Highly specialized mechanisms are required for transporting cobalamin (vitamin B12) into and out of mammalian cells. This review describes the key role of the cobalamin-binding proteins in meeting the stringent requirements for transport of this essential nutrient. Also summarized are the various defects capable of impairing intestinal absorption and transcellular transport of cobalamin. Elucidation of these defects proved crucial for our current understanding of normal cobalamin transport mechanisms.

Biological Transport, Active↗
PubMed1979

Evidence for involvement of cyclic nucleotides in intrinsic factor secretion by isolated rabbit gastric mucosa.

Secretion of intrinsic factor (IF) has previously been demonstrated in isolated rabbit fundic mucosa maintained in organ culture. We have now investigated the possibility that cyclic nucleotides may play a role in IF secretion. A phosphodiesterase inhibitor, 3-isobutyl methylxanthine (IBMX), stimulated IF secretion nearly fourfold while increasing tissue levels of both cyclic AMP (cAMP) and cyclic GMP (cGMP). Peak IF secretion in response to IBMX was not reached until after tissue cAMP levels were maximal. Dibutyryl cAMP and 8-Br-cAMP increased secretion by the same order of magnitude as did IBMX, whereas corresponding analogues of cGMP had no such effect. Histamine increased secretion of IF. In the presence of 40 microM IBMX, histamine elevated tissue levels of cAMP, but not of cGMP, and the stimulating effect of 10 microM histamine on IF secretion was potentiated. An H2 receptor antagonist, cimetidine, blocked the increases in IF secretion and tissue cAMP levels due to histamine, and the increase in IF secretion due to IBMX. These observations are consistent with a role for cAMP in the secretion of IF by isolated gastric mucosa.

1-Methyl-3-isobutylxanthine↗
PubMed1978

Macromolecular secretion by isolated gastric mucosa: fundamental differences in pepsinogen and intrinsic factor secretion.

The secretion of pepsinogen and intrinsic factor (IF) in response to various known stimulators and inhibitors of gastric acid secretion was examined in isolated rabbit gastric mucosa maintained in organ culture. Acetylcholine (10(-8) M) stimulated stimulated both pepsinogen (P less than 0.01) and IF (P less than 0.01) secretion and this stimulation was blocked by atropine. Parasympatholytic agents did not alter unstimulated (basal) secretion of pepsinogen even at high concentrations (atropine, 10(-2) M or propanthelene bromide, 5 X 10(-3) M), however, at these concentrations basal IF secretion was abolished. Histamine (10(-4) and 10(-2) M) had no effect on pepsinogen secretion but stimulated IF secretion (P less than 0.001). Antagonism of H2 receptors by cimetidine reduced both basal and histamine-stimulated IF secretion, but pepsinogen secretion remained unaltered. Under the conditions of the above experiments the gastric mucosal surface was not exposed to HCl but was constantly buffered by culture medium at pH 7.4. When we applied 50 mN HCl to the mucosal surface of the biopsies, pepsinogen secretion doubled (P less than 0.001) but IF secretion was abolished. These studies have clearly documented that: (1) fundamental differences exist in the responses of pepsin and IF secreting cells; (2) H+ ions bathing the mucosal surface of the stomach may influence the results of experiments designed to examine the mechanisms of gastric mucosal macromolecular secretion.

Acetylcholine↗
PubMed1976

Free intrinsic factor in the small intestine in man.

Human jejunal and ileal contents and ileostomy effluents were examined for the presence of free intrinsic factor. This was detected in 9 out of 10 jejunal and three out of five ileal aspirates and in one of three ileostomy effluents studied. The intrinsic factor in the ileal effluent was shown to be physiologically active. The presence of free intrinsic factor in the small intestine has considerable physiological significance in maintaining the enterophepatic circulation of vitamin B12. It would also permit the absorption of any free vitamin B12 produced by ileal bacteria.

Body Fluids↗
PubMed1975

Vitamin B12 absorption--a study of intraluminal events in control subjects and patients with tropical sprue.

The intraluminal fate of orally administered radioactive vitamin B12 has been studied in control subjects with normal vitamin B12 absorption and those with vitamin B12 malabsorption due to tropical sprue. In control subjects 1 to 21% of the dose was bound to sedimentable material and 37 to 75% was bound to immunoreactive intrinsic factor. In subjects with vitamin B12 malabsorption due to tropical sprue, the results were identical with the control subjects. Bacteriological studies showed a statistically significant correlation between both the number of flora in the jejunum and the number of bacteroides in both the jejunum and ileum and vitamin B12 malabsorption. In patients with tropical sprue who have normal intrinsic factor secretion, the vitamin B12 absorptive defect is not due to binding of the vitamin to bacteria or to alteration to the intrinsic factor vitamin B12 complex in the intestinal lumen. The lesion appears to be one of the mucosal cell receptors or of the cells themselves, possibly caused by bacterial toxins.

Bacteroides↗