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Biomedical subjects

Y Niv

Publications and source records attributed to Y Niv.

At least 91 records · Page 5Linked to original sources
PubMed1995

Abolition of postprandial alkaline tide in arterialized venous blood of duodenal ulcer patients with cimetidine and after vagotomy.

OBJECTIVE: Alkaline tide is the observed alkalinization of blood and urine after stimulation of gastric acid secretion. In previous studies, we found good correlation between gastric acid output and alkaline tide in arterialized venous blood. METHODS: In the present study, the alkaline tide phenomenon was further investigated in 26 duodenal ulcer patients (seven post-vagotomy) after a test meal, before and after cimetidine pretreatment. RESULTS: Alkaline tide was demonstrated in everyone of the 19 duodenal ulcer nonvagotomized patients but in only two of the seven vagotomized patients; base excess mean rise of 1.05 +/- 0.14 mEq/L/45 min versus -.07 +/- 0.23 mEq/L/45 min (mean +/- SE, p < 0.001). Decrease in alkaline tide after cimetidine was demonstrated in the nonvagotomized group: 1.05 +/- 0.14 mEq/45 min versus -0.03 +/- 0.16 mEq/45 min, before and after cimetidine, respectively (mean +/- SE, p < 0.001). Urinary alkaline tide was demonstrated in only 4/19 and 2/19 of the first group (with and without cimetidine, respectively) and in only 1/7 of the post-vagotomy group. CONCLUSIONS: Our results suggest an association between gastric acid secretion and blood alkaline tide, because both are inhibited by cimetidine or vagotomy.

Adult↗
PubMed1995

Calcium channel blocker decreases pentagastrin-stimulated alkaline-tide: a role for extracellular calcium in gastric acid secretion.

We previously showed that repeated stimulation of the gastrin receptor may lead to down-regulation. We hypothesized that entry of extracellular Ca2+ may replenish cytosolic Ca2+ and enable continuation of the acid-secretion process. Pentagastrin-stimulated alkaline-tide study was performed in seven duodenal ulcer patients on 2 separate days--with and without pretreatment with verapamil (Ca2+ channel blocker). The alkaline-tide test may substitute the conventional gastric acid collection as previously described. A significant rise in base excess after pentagastrin injection was found on the first day of the study, from 0.400 +/- 1.233 to 2.230 +/- 1.330 (mean +/- SD, P = 0.02). On the second day the rise was not statistically significant, from -0.200 +/- 0.838 to 0.440 +/- 1.200 (mean +/- SD, P = 0.27). In 6 of the 7 patients the alkaline-tide decreased from 45.29 +/- 21.75 mEq/45 min on the first day to 21.56 +/- 17.48 mEq/45 min on the second day of the study (mean +/- SD, P = 0.029), a decrease of 63.6 +/- 36.2%. Our findings may support a dual source for Ca2+, the second messenger in gastrin-dependent gastric acid secretion. The first increase of intracellular Ca2+ comes from cellular stores, and the second from extracellular source by Ca2+ channels, which can be blocked by verapamil.

Acid-Base Equilibrium↗
PubMed1995

Demographic data from a hospital case series of endoscopically-diagnosed benign peptic ulcer in southern Israel, 1989-1990.

BACKGROUND: A knowledge of the clinical and epidemiological features of duodenal and gastric ulcer is of importance to clinicians and other health care providers. These aspects of ulcer disease have not been studied previously in the Negev region of southern Israel, which is home to 300,000 Jews and 60,000 Bedouin Arabs. METHODS: Clinical, demographic and risk factors were analyzed in a case series of benign duodenal and gastric ulcers (first or recurrent attack) diagnosed at endoscopy at the Soroka Medical Center in the years 1989-1990. RESULTS: There were 336 cases of duodenal ulcer (321 cases in Jews, 15 in Bedouins) and 79 cases of gastric ulcer (all in Jews). The annual rate of endoscopically-detected duodenal ulcer was 54/10(5) in Jews and 13/10(5) in Bedouins. The annual ratio of endoscopically-detected gastric ulcer in Jews was 13/10(5). The ratio of male to female patients was 2.7 for duodenal ulcer in Jews and Bedouins, and 1.9 for gastric ulcer in Jews. The mean age +/- standard deviation at diagnosis was 48 +/- 17 years for duodenal ulcer and 63 +/- 15 years for gastric ulcer (p < 0.001). Duodenal ulcer was significantly commoner than gastric ulcer at all ages, but the ratio DU:GU decreased with increasing age, so that by age 48 years, 20% of all endoscopically-diagnosed ulcers were GU. Of several risk factors examined, smoking was associated with duodenal ulcer (p < 0.05) but not gastric ulcer. Occupation was not a risk factor. Duodenal ulcer was 1.3 times more frequent in winter than summer. CONCLUSIONS: Endoscopically-diagnosed duodenal and gastric ulcer is commoner in Jews than Bedouins and in men than women. Duodenal ulcer is commoner than gastric ulcer and presents at a younger age. Smoking is a risk factor for duodenal ulcer, and European and American ethnic origin is a risk factor for duodenal and gastric ulcers. Bleeding is associated with one-third of endoscopically-diagnosed ulcers in this institution.

Adolescent↗
PubMed1995

Induction of the differentiated phenotype in human colon cancer cell is associated with the attenuation of subcellular tyrosine phosphorylation.

In the present study we have determined membrane, cytosolic, and cytoskeleton-associated tyrosine protein kinase (TPK) activity in human colon cancer cell lines exposed to (i) the differentiation-promoting agents sodium butyrate and 8-chloro-cyclic-adenosine 3',5'-monophosphate (8-Cl-cAMP), (ii) tyrphostins, specific TPK inhibitors, or (iii) differentiation-inducing culture manipulations. Treatment of human colon cancer cell lines, LS 174T, COLO 205, and SW620, with sodium butyrate and 8-Cl-cAMP or tyrphostins AG-30 and AG-34, significantly attenuated TPK activity concomitantly with an increase in the activity of alkaline phosphatase, an enzymatic marker of intestinal cell differentiation. The differentiated phenotype induced in Caco-2 and HT-29 colon cancer cells by culture manipulation was associated with a significant decrease in cytoskeleton-associated TPK activity and marked activity of alkaline phosphatase (AP). Electron microscopy and freeze-fracturing analysis of HT-29 cells showed that the gradual transition from the undifferentiated to the differentiated phenotype resulted in the acquisition of a distinct polarized morphology. Immunocytochemical phosphotyrosine analysis of cultured SW620 cells showed positive staining mostly localized in zones of focal contacts. A marked reduction in phosphotyrosine staining with notable changes in cell morphology was observed in SW620 cells exposed to tyrphostins. Cumulatively, the present results indicate that the induction of the differentiated phenotype in colon cancer cells is associated with a marked decrease in TPK activity and tyrosine phosphorylation.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1994

Adenocarcinoma in the rectal segment in familial polyposis coli is not prevented by sulindac therapy.

Sulindac, a nonsteroidal anti-inflammatory drug, causes regression of polyps in familial polyposis coli and may prevent new lesions. However, it is not clear whether the effect of sulindac in preventing polyps also applies to carcinoma. This case report describes a patient with familial polyposis coli who developed a carcinoma in a rectal segment after subtotal colectomy and ileorectal anastomosis. She had been treated with 450 mg sulindac daily for 28 months and was free of polyps during the latter 12 months of this period. However, despite intensive endoscopic follow-up, she developed an adenocarcinoma of the rectum. This finding may have important implications for our understanding of the development of colon cancer in familial polyposis coli and the use of sulindac to prevent it. Development of de novo carcinoma in microadenomatous tissue of the rectal mucosa, which bypasses the polyp-cancer sequence, must be considered as a possibility in these patients.

Adenocarcinoma↗
PubMed1994

Increased tumorigenicity after differentiation of colon cancer cell line: absence of association with mucin synthesis.

BACKGROUND/AIMS: Postconfluence differentiation followed by a decrease in mucin synthesis has been described for the colonic adenocarcinoma cell line Caco-2. Because the onset of differentiation usually heralds the end of proliferation, we expected Caco-2 would be more tumorigenic in the exponential phase. Thus, we compared tumorigenicity, clonigenicity, and mucin synthesis in the exponential and stationary growth phases. METHODS: We estimated mucin synthesis in Caco-2 cells by measuring the amount of high-molecular-weight [3H]glucosamine-labeled glycoprotein released into the culture medium and in the cytosolic fraction. Colony forming efficiency in soft agar and tumorigenicity in nude mice were assessed. RESULTS: Cells in the exponential phase synthesized significantly more mucin compared with stationary phase cells. Pretreatment with benzyl-GalNAc reduced production in both phases but did not change clonigenicity. Colonies did not grow from cells seeded in the exponential phase. The average weight of xenografts raised from postconfluence cells was twice that of xenografts raised from cells in the exponential phase. CONCLUSIONS: Neither exponential cell growth nor increased mucin production predicts clonigenicity and tumorigenicity. It is speculated that a stable process takes place in Caco-2 cells after confluence which makes them more clonigenic in vitro and enhances tumor growth in vivo.

Alkaline Phosphatase↗
PubMed1994

Increasing serum creatinine and age reduce the response to hepatitis B vaccine in renal failure patients.

The relationship between diminished response to hepatitis B vaccine in renal failure patients and serum creatinine level, age and other factors is unknown. The immune response of patients with renal failure of varying severity to hepatitis B vaccine was determined in this study. Sixty-eight patients with renal failure of varying severity who were negative for hepatitis B markers received four doses of hepatitis B vaccine, and anti-HBs titers were determined at 0, 1, 2, 3, 6, 8 and 12 months. Maximum anti-HBs titers were seen at 8 months. At this time 86% of patients with creatinine < or = 4 mg/dl but only 37% with creatinine > 4.0 mg/dl had a protective titer of > or = 10 mIU/ml (p < 0.002). Age was inversely related to anti-HBs titer (p = 0.045) and was independent of serum creatinine in predicting antibody response. We conclude that all patients with chronic renal failure should be immunized against hepatitis B as early as possible in the development of their disease, to ensure maximum response, and to minimize the effects of elevated serum creatinine and increasing age.

Adult↗
PubMed1993

Further applications of blood gas analysis to gastric acidity determination.

It has been shown that the transient increase in total body bicarbonate that accompanies any acceleration of gastric acid secretion (the 'alkaline tide') is derivable from the associated changes in base excess in arterial blood and is precisely equivalent to the amount of acid secreted when the latter is simultaneously recovered. For the alkaline tide to qualify as a 'tubeless' measure of acid secretion, its equivalence to the latter has to be demonstrated without simultaneous aspiration of gastric juice. We therefore studied the course of the alkaline tide following pentagastrin injection and its relationship to pentagastrin-stimulated acid secretion as measured by aspiration on a separate occasion. In 12 duodenal ulcer patients, the sequential changes in base excess in arterial blood in response to pentagastrin invariably described coherent curves. Peak values occurred most frequently 45 min after injection. In 12 similar patients, alkaline tide 45 min after pentagastrin, as per analysis of arterialized venous blood, correlated well (r = 0.86) with 'peak acid output' (PAO) as measured by aspiration at another time. In 14 patients post vagotomy and pyloroplasty for duodenal ulcer, the 45-min alkaline tide was determined as above and PAO was predicted from the previously established regression-line: The 3 patients with recurrent duodenal ulceration had the highest predicted values for PAO, clearly discriminating them from the others. Measurement of alkaline tide holds promise as a valuable substitute for conventional gastric analysis. For the sake of accuracy, readings should be based on individually constructed time-curves of base excess, in preference to the raw data. Arterialized venous blood appears to be satisfactory substitute for arterial blood for studies of this type.

Adult↗
PubMed1993

Gastroesophageal obstruction from food in an epiphrenic esophageal diverticulum.

An epiphrenic diverticulum is usually accompanied by esophageal motor disorders, diaphragmatic hernia, or esophagitis. Symptoms are rarely attributable to the diverticulum except very rarely when no other explanation for dysphagia or chest pain is demonstrated. We describe acute esophageal obstruction from food accumulating in an epiphrenic diverticulum and compressing the gastroesophageal junction, and we confirm the mechanism with an artificial balloon.

Aged↗
PubMed1993

Pathogenetic aspects of persimmon bezoars. A case-control retrospective study.

To prove that ingestion of unpeeled persimmon is necessary for the development of a persimmon phytobezoar, we interviewed 15 patients, in most of whom this condition developed after peptic ulcer surgery. We compared the study group with a control group of 15 patients who had undergone peptic ulcer surgery but did not have a bezoar. In contrast with the control group, most patients with bezoars had ingested unpeeled fruits (p < 0.01). While ingestion of persimmon carried a 9.8-fold risk of bezoar development, ingestion of the unpeeled fruit increased the risk of this complication 56 times over that of age- and sex-matched controls. We recommend that patients who have undergone ulcer surgery be warned particularly against eating unpeeled persimmons.

Bezoars↗
PubMed1993

A new diagnostic test for incomplete vagotomy: experimental study in dogs.

Despite the decline in the number of operations for intractable duodenal ulcer disease, there are still many patients who suffer from the side effects of vagotomy. Incomplete vagotomy may be a significant cause of surgical treatment failure. Diagnosis of incomplete vagotomy is not easy since there is no reliable, safe, single test available for this purpose. We hypothesized that incomplete vagotomy can be made temporarily complete in response to a muscarinic blocking agent. A gastric cannula was inserted and vagotomy performed in 12 female dogs, which was incomplete in 6 and complete in 6 dogs. Gastric acid secretion was stimulated for 2 h with i.v. pentagastrin at a rate of 6 micrograms/kg per h. After the first hour 6 mg/kg pirenzepine (M1 muscarinic receptor antagonist which may block the effect of intact vagal fibers on postganglionic submucosal neurons) was added i.v. In the complete vagotomy dogs there was no significant decrease in gastric output rate: 12.28 +/- 4.06 mEq/h in the first hour, and 12.00 +/- 3.80 mEq/h in the second hour (mean +/- SE, P = 0.963, t = 0.048). In the incomplete vagotomy dogs a significant decrease in gastric acid output rate was observed: 10.19 +/- 1.10 mEq/h in the first hour, and 4.33 +/- 0.95 mEq/h in the second hour (mean +/- SE, P = 0.002, t = 4.029). We conclude that a pentagastrin/pirenzepine test may differentiate between complete and incomplete vagotomy in the dog.

Animals↗
PubMed1993

Hyperplastic polyp and colonic neoplasia. Is there an association?

Hyperplastic polyps are regarded as non-neoplastic lesions with no malignant potential. However, several case reports and a clustering phenomenon suggest that they may arise in abnormal colonic that is predisposed to develop neoplastic lesions. The hyperplastic polyp also displays markers associated with colorectal cancer. In addition, several recent articles have addressed the question of hyperplastic polyp in the distal colon as a marker of more proximal adenomatous polyp. Many endoscopists discovering a distal hyperplastic polyp will wish to ensure the absence of a proximal neoplastic lesion.

Colonic Neoplasms↗
PubMed1992

Mucin synthesis and secretion in relation to spontaneous differentiation of colon cancer cells in vitro.

The synthesis and secretion of mucin-like high-molecular glycoprotein was studied in 2 human colon cancer cell lines that spontaneously differentiate in culture (Caco-2 and T84) and in 2 cell lines that do not spontaneously differentiate (LS174T and HT29). Mucin, quantitated by 3H-glucosamine labelling and chromatography on Sepharose CL-4B was found to be produced by all 4 cell lines. The mucinous nature of the labelled high-molecular glycoprotein was verified by enzymatic degradation treatments (heparinase, hyaluronidase, chondroitinase ABC, and N-glycanase), alkaline-borohydride treatment, inhibition of labelling by the glycosylation inhibitor benzyl-alpha-GalNAc, and by CsCl-density-gradient centrifugation. In all 4 cell lines, an inverse correlation of mucin synthesis with cell density was demonstrated. In Caco-2 cells, the spontaneous post-confluent enterocytic differentiation with increased brush-border enzyme expression was associated with a decrease in mucin synthesis and in the activities of polypeptidyl GalNAc transferase and beta 1,3-galactosyltransferase activity. Using cDNA probes for 2 distinct human intestinal mucins (MUC2 and MUC3), we found that all 4 colon cancer cell lines expressed mucin message, but the types of mucin mRNA expressed differed. These data indicate that mucin-like glycoproteins can be synthesized by cell lines derived from non-mucinous colon cancer, whether or not they undergo spontaneous differentiation in culture. These cell lines may serve as in vitro models for studying apomucin heterogeneity and control of mucin gene expression.

Cell Differentiation↗