Characterization of calcitonin- and adrenocorticotropin-producing human cloned cell lines.

We have developed three human cloned cell lines that produce immunoreactive human calcitonin (ihCT) and ACTH (iACTH) as well as exhibit characteristics of cultured neural cells. Clones HMS-41/I, -78/2, and -98/2 were developed from cell lines HeLa AV3, MBA 9812 (bronchogenic carcinoma), and SW 267 (pheochromocytoma), respectively. Karyological analysis of both the parent and the cloned cell lines confirmed the identity of HeLa AV3 and MBA 9812. When grown in serum-free media designed for culturing neural cells, the patterns of production for both ihCT and iACTH varied among the clones. The multiple patterns of hormone production suggest that the mechanisms involved in the biosynthesis, processing, and secretion of these hormones differ among the clones. The clones contain neuron-specific enolase and the putative neurotransmitters beta-alanine and gamma-amino butyric acid, and they respond to cAMP analogs by differentiating, as noted by the extension of neurites (except the HeLa-derived HMS-41/I). The iACTH extracted from cells and synthetic ACTH exhibited equivalent profiles upon isoelectric focusing. The forms of ihCT noted in cell extracts were similar to those observed in extracts of human tumor tissue. Our rabbit antiserum to hCT failed to detect ihCT in those cell extracts prepared for ACTH determination or in extracts of rat pituitaries, but it did detect CT in rat thyroids by both RIA and immunofluorescent procedures. We concluded that our antisera to hCT do not detect the precursor form of ACTH. The availability of these cloned cell lines provides model systems for examining the production of these peptide hormones and the concomitant expression of neural and endocrine characteristics.

Subclinical chronic pancreatitis in type I hyperlipoproteinemia.

Severe pancreatic exocrine insufficiency was demonstrated in a 41 year old man with familial type I hyperlipoproteinemia (fat-induced hyperlipemia). Plasma triglyceride concentration failed to increase significantly with increased dietary fat intake, and fecal fat excretion was markedly increased. Indices of intestinal function were normal. Pancreatic enzyme therapy resulted in reduced fat excretion and increased plasma triglyceride concentration. Secretin stimulation tests revealed impaired duodenal fluid volume, bicarbonate and pancreatic enzyme responses. Insulin-dependent diabetes mellitus had been diagnosed three years earlier. No attacks of acute pancreatitis had occurred in the preceding 20 years, and it is suggested that pancreatic damage may have resulted from repeated subclinical pancreatic insults due to elevated plasma lipid levels. This report is the first to indicate that pancreatic exocrine insufficiency may occur as a late complication of hyperlipemic disorders in the absence of recurrent acute pancreatitis. Steatorrhea may not be apparent because of therapeutic restriction of dietary fat, and the first manifestation of pancreatic exocrine disease may be an amelioration of fat-induced hyperlipemia.

Viral gastroenteritis induced by the Hawaii agent. Jejunal histopathology and serologic response.

Peroral jejunal biopsies were performed in seven normal volunteer subjects prior to, 48 hours after and two weeks after the administration of the Hawaii agent of viral gastroenteritis. Light and electron microscopic examination revealed an intact mucosa with blunted villi, shortened and distorted microvilli, swollen mitochondria and intercellular edema. These histologic changes were seen only in acutely ill volunteer subjects and were absent two weeks after illness in three of four who were previously ill. This reversible lesion was similar to, but not identical with, that previously described in viral gastroenteritis induced by the Norwalk agent. Serum antibody increases in response to the Hawaii agent as measured by immune electron microscopy were present in three of four ill volunteer subjects and in none of three who remained well.

Heterogeneity of chloramine T- and lactoperoxidase-radioiodinated human calcitonin.

Radioiodination reportedly damages peptides, but the nature of the damage has not been adequately examined. Utilizing isoelectric focusing, we examined the products of Chloramine T- and lactoperoxidase-directed radioiodinations of human calcitonin. Initially, the reaction products were purified by adsorption onto and elution from microfine silica (QUSO-G32). Radioiodination of the calcitonin by Chloramine T and lactoperoxidase produced a heterogeneous population of 125I-labeled peptides exhibiting apparent isoelectric points that were more acidic than that of unlabeled synthetic calcitonin. Variation in the products among radioiodinations and the inability of QUSO-G32 to resolve the components of the reaction mixture prompted our examination of alternative purification procedures. Anion-exchange chromatography on QAE-Sephadex effectively separated [125I]diiodotyrosine containing calcitonin from free iodine and [125I]iodolactoperoxidase. Our data indicate that: (a) radioiodination of human calcitonin by Chloramine T and lactoperoxidase induced alteration in the peptide as evidenced by isoelectric point, (b) specific [125I]iodopeptides vary in incidence and relative abundance among radioiodinations, (c) identification of the labeled amino acid in [125I]iodopeptides cannot ensure intergrity of the molecule, and (d) isoelectric focusing provides a method of comparing the products of peptide radioiodinations among laboratories.

Pancreatic cholera: beneficial effects of treatment with streptozotocin.

Two patients with pancreatic cholera and islet-cell carcinoma were treated with intra-arterial streptozotocin. Before therapy, they had stool volumes from 2 to 8 liters per day and required 200 to 800 mEq per day of supplemental potassium. After three to five doses of streptozotocin (1.5 per square meter), both stool volume and number and size of hepatic metastases decreased markedly. One patient has had normally formed stools for 12 months; the other had a 90 per cent reduction in stool volume for 13 months with additional therapy. Both patients' serum potassium returned to normal without need for supplementation. Jejunal adenylate cyclase activity was normal in both, and plasma vasoactive intestinal peptide was detectable in only one. After chemotherapy, these findings showed no consistent change. Pharmacologic studies suggest that arterial administration increased either tumor or hepatic extraction (or both) of streptozotocin by two times and decreased renal exposure to this nephrotoxic drug by one third.

Saline lavage: a rapid, effective, and acceptable method for cleansing the gastrointestinal tract.

The standard preparation for cleansing the gastrointestinal tract for diagnostic studies such as barium enema usually involves dietary restrictions, purgatives, and cleansing enemas. This preparation is time consuming, often uncomfortable for the patient, and frequently unsuccessful. In this study, we examined the efficacy of saline lavage (without dietary restrictions or cleansing enemas) as a gentle, alternative method for cleansing the bowel, and compared lavage to the standard castor oil method of bowel preparation. Lavage cleansing was preferred by 75% of patients who had previously experienced a castor oil preparation. Although 11% of patients could not consume an adequate (4-liter) lavage volume, there was no significant difference in preparation success rate between the remaining lavage patients and the castor oil patients. Total preparation time for lavage (3 +/- 1 hr) was 60% less than for castor oil. The anticipated dehydration produced by castor oil and the hydration produced by lavage were confirmed. No significant changes were noted, however, in serum electrolytes with either method of preparation. Additional early studies are promising for the lavage method when used in inflammatory bowel disease patients and as a cleansing preparation for colonoscopy.

Jejunal adenylate cyclase activity in human subjects during viral gastroenteritis.

The histopathological changes that occur in the jejunal mucosa of humans infected with the Norwalk or Hawaii agent of acute infectious nonbacterial gastroenteritis ("viral" gastroenteritis) have ben well characterized. The pathogenesis of diarrhea in this syndrome remains unknown; however, recent reports have suggested a possible role for the adenylate cyclase system. In this combined paper, two groups of investigators working independently and employing slightly different techniques report that: (1) there is marked interindividual variation in the apparent specific activity of adenylate cyclase in human jejunal biopsy tissue; (2) such variation can be minimized by expressing enzyme activity as a fraction of maximal that can be stimulated by 10(-2) M sodium fluoride; and (3) adenylate cyclase activity in jejunal mucosa is not increased during diarrhea or illness in human viral gastroenteritis, therefore suggesting no role for the adenylate cyclase system in the pathogenesis of diarrhea in this common clinical entity.