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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Improvements in the collagenase perfusion techniques have made isolated rat hepatocytes a popular model in which to study hepatic function. Our knowledge of hepatic amino acid transport has been advanced as a result of this methodology. Translocation across the hepatocyte plasma membrane can, in some instances, represent the rate-limiting step in the overall metabolism of certain amino acids. Furthermore, regulation of amino acid uptake by hepatocytes appears to play a role in diabetes, and perhaps in malignant transformation. Comparisons between normal adult hepatocytes and several hepatoma cell lines show basic differences in amino acid transport. There are at least eight distinct systems in normal hepatocytes for transport of the hormones. Systems A and N exhibit enhanced uptake rates after the cells have been maintained in the absence of extracellular amino acids, a phenomenon termed adaptive control. Further studies using isolated hepatocytes will increase our basic understanding of membrane transport processes and their regulation.
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PMID:Amino acid transport in isolated rat hepatocytes. 681 49

A transient hypoglycemia was found 4 hrs after injection of 25-hydroxycholecalciferol (25-HCC) in mice. This was not associated with any significant alteration in the serum insulin concentration, suggesting that the hypoglycemic response is due to extrapancreatic factors. Pretreatment with 25-HCC did not affect the development of alloxan diabetes.
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PMID:Transient hypoglycemia following 25-hydroxycholecalciferol administraton to mice. 700 May 8

Monolayer cultures of minimal deviation hepatoma cells (H4-II-E-C3') bound and degraded insulin specifically, the apparent Ki value for insulin inhibition of both processes being 1 x 10(-8) M, indicating that cell-bound 125I-insulin is the substrate for subsequent hormone degradation in these cells as in isolated hepatocytes.1 The time course of insulin binding to its receptor depended on hormone concentration and temperature. Degradation of insulin also depended highly on temperature, with little or no degradation occurring at less than 20 degrees C, a temperature below which a membrane-lipid phase transition may block homone translocation or uptake. The effects of various agents on the binding and degradation of 125I-insulin also were tested. Agents believed to inhibit intralysosomal degradation of various proteins also inhibited the degradation of 125I-insulin by H4 cells (chloroquine, ammonium chloride, procaine, and lidocaine); inhibitors of energy production (dinitrophenol, sodium cyanide) inhibited degradation; an agent which inhibits microtubule function (vinblastine) blocked insulin degradation; and methylamine, reported to prevent receptor aggregation,2 also interfered with insulin processing. These findings are consistent with a model for cellular insulin processing, comprising receptor binding, clustering of receptors, endocytotic uptake, intralysosomal degradation, and extracellular release of some degradation products. H4 cells were highly sensitive to insulin. The KE for a half-maximal response of hormone-stimulated incorporationof 14C-glucose into glycogen was 10(-11) M insulin, corresponding to less than 1% receptor occupancy. This response was also mimicked by concanavalin A at a concentration of 10 microgram/ml. Vinblastine and chloroquine both significantly inhibited insulin-stimulated glucose incorporation into glycogen without affecting basal levels. However, since these inhibitory effects were not relieved by addition of excess insulin, it seems unlikely that their action on glycogen synthesis was exerted only at the level of the generation of an active intermediate or degradation product from hormone-receptor complexes. The hormone-sensitive H4 cells thus provide a useful system for further studies examining the role of insulin-receptor uptake in hormone action, receptor regulation, and signal termination.
Diabetes 1980 Nov
PMID:Cultured hepatoma cells as a model system for studying insulin processing and biologic responsiveness. 700 May 84

In 1096 cases of death (autopsy rate 63.8%) the accuracy of clinical diagnoses was investigated by comparing clinical diagnoses with recorded autopsy findings. -- In 81.3% of the cases the primary disease had been determined correctly. In more than half of these cases the immediate cause of death or an additional disease contributing to death had not been correctly identified. In 16% of the cases the diagnosis proved to be inadequate. -- In 2.6% of all cases the primary disease, cause of death and accompanying illnesses were misdiagnosed. Most of these patients had stayed in the hospital for a much shorter time than the rest of the patients. -- Among conditions clinically diagnosed as cirrhosis of the liver, pulmonary embolism, myocardial infarction, cerebral hemorrhage, and malignant tumors -- pulmonary embolism was by far the most frequent condition to go unrecognized, i.e. in 50% of th cases in which it was present. Primary liver cell carcinoma proved to be the malignant tumor most frequently not identified by clinical studies. -- Four clinical diagnoses (shock, septicemia, diabetes mellitus and uremia) were often unsupported by morphological findings. Yet there were 13 clinically undiagnosed cases of septicemia in which findings at post mortem examination revealed this condition. These cases also underline the importance of autopsies.
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PMID:Autopsy and clinical diagnosis. 1879 61

The levels of serum secretory component (SC) were measured in 147 patients with digestive disease. Decreased levels were found patients with acute hepatitis, HBs-antigen associated chronic hepatitis, HBs-antigen associated liver cirrhosis and hepatoma. Normal levels were observed in patients with diabetes mellitus, gastric cancer and colonic carcinoma. Elevated levels were found in patients with cholecystitis, obstructive jaundice and acute pancreatitis. The serum SC level in almost all disease groups showed no correlation with immunoglobulin levels.
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PMID:Studies on secretory component in digestive disease. III. Levels of serum secretory component in digestive disease. 743 18

Department of molecular basis of semiotics was organized in 1986. The main task of the department was to work out new approaches in estimation of the state of immune and blood system at the tissue, cell and molecular levels, using biochemical, biophysical and molecular biology techniques. There are several main directions of scientific investigations at the department. Most informational methods were collected in "immunological portrait" for differential diagnostic and complex investigation of the immune system of autoimmune patients. This group of techniques was used to study changes in the immune system of Kievites after the Chernobyl disaster. A decrease of complement and thymic serum activity was detected. Antibodies against nuclear components appeared in 20% of donors. And a higher of circulating immune complex of low molecular weight was observed. Low level of thymic serum activity in blood of autoimmune patients with rheumatoid arthritis, lupus erythematosus, diabetes, herpes and other depends on the appearance of zinc-independent timuline inhibitor less then 2000 D. Another kind of thymic hormone inhibitors was detected in thymectomized adult mice. Its effect disappears when zinc added in blood rather due to competition for lymphocyte surface receptors timuline and its inactive analogue than other mechanism. Therapeutic effect of UV irradiation of patients' blood was shown to be closely connected with the changes in thymic serum activity in respect to stabilization of thymic hormone/inhibitor ratio. The immunochemical techniques were used to detect and investigate tumor-associated chromatin antigens in human and animal tumor cells. Antigens not found in normal tissues were detected when using rabbit antibodies against chromatin of rat hepatocarcinoma and human colon and carcinoma.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Department of the molecular bases of semiotics]. 757 Oct 65

To develop a model somatic gene therapy system for diabetes, a human hepatoma cell line (HEP G2) was transfected with a mammalian expression vector carrying the full-length human insulin cDNA. More proinsulin than insulin was released daily by the stably transformed cell line (HEP G2ins). However, on acute stimulation with 5mM 8-Br-cAMP and 10mM theophylline the HEP G2ins cells released predominantly insulin into the medium. The cells did not secrete insulin in response to glucose. Examination of acid-ethanol extracts confirmed insulin was preferentially being stored. Immunohistochemical analysis of the cells also showed (pro)insulin was being stored. Electron microscopy revealed large membrane-bound vacuoles, containing electron-dense material, which were not seen in control cells. Glucokinase activity and albumin secretion of the transfectants were unaltered from the controls. Five-minute pulse-chase labelling of the HEP G2ins cells with 3H-leucine confirmed insulin synthesis in the presence of 20mM glucose and 5mM 8-Br-cAMP. A dose-response curve for insulin synthesis was also generated to increasing concentrations of glucose with a half Vmax of 4.9mM. Our results show that the introduction of insulin cDNA into a human hepatoma cell line results in synthesis, storage and acute regulated insulin release and lend credence to the possibility of engineering a liver cell to secrete insulin acutely in response to physiological stimuli.
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PMID:Functional expression of the human insulin gene in a human hepatoma cell line (HEP G2). 761 54

Cytochromes P450 (P450s) are inducible drug-metabolizing enzymes involved in the metabolism of numerous endogenous and exogenous substrates. The regulation of some of these enzymes during experimental diabetes has been reported, but the direct involvement of insulin and the mechanism of its action remain unclear. The aim of our work was to study the effects of insulin on P450 2B and 2E expression in differentiated Fao hepatoma cells. Exposure of the cells to 0.1 microM insulin caused 60% and 80% decreases in the steady state levels of P450 2B and 2E proteins, respectively, within 24 hr. Before this, a rapid decrease in the corresponding messages was observed. Indeed, 5-6 hr of insulin treatment produced 80 and 50% decreases in P450 2B and 2E mRNA levels, respectively. Nuclear run-on transcription and mRNA turnover studies were performed to determine the mechanism (transcriptional and/or post-transcriptional) by which insulin modulated these mRNA levels. From our results, it can be concluded that insulin down-regulates the expression of P450 2B by shortening the half-life of its mRNA (half-lives of 6.9 hr without insulin and 3.6 hr with insulin), whereas it down-regulates the expression of P450 2E both by weak repression of the transcription rate (-30%) and, in particular, by acceleration of its mRNA turnover (half-lives of 8.5 hr without insulin and 3.3 hr with insulin).
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PMID:Insulin down-regulates cytochrome P450 2B and 2E expression at the post-transcriptional level in the rat hepatoma cell line. 770 Feb 45

Reduced expression of calmodulin (CaM) and decreased activity of low Km cyclic AMP (cAMP) phosphodiesterase (PDE) are associated with uncontrolled diabetes. This condition can be readily mimicked in hepatocytes cultivated in insulin-depleted medium (Solomon, et al J. Lab. Clin. Med. in press, 1994). To investigate the relationship between CaM and low Km cAMP PDE gene expression in response to insulin, we specifically blocked expression of the three CaM genes by antisense oligonucleotides under insulin-deficient and -sufficient conditions in a rat hepatoma cell line, H-411E. We observed that both the low Km cAMP PDE activity and the steady state levels of CaM mRNA were increased in response to insulin by 50 and 100%, respectively. When antisense oligonucleotide to CaM I, II or III was added to the cultures, only CaM I antisense oligonucleotide blocked insulin stimulation of both CaM I mRNA and protein with concommittant marked inhibition of insulin's expected stimulation of low Km cAMP PDE. Furthermore, in another experiment utilizing both antisense and oligonucleotide probes specific for CaM I, II, or III together, only CaM I mRNA expression was blocked. We conclude that H-411E cells respond to insulin by appropriate increases in CaM transcripts. Furthermore, the stimulatory effect of insulin on both CaM synthesis and activation of low Km cAMP PDE could be blocked by antisense to CaM I, but not II or III genes. Therefore, in addition to the above conclusions, H-411E hepatoma cells appear to be an excellent in vitro system to explore the molecular mechanisms by which CaM and low Km cAMP PDE genes are regulated in the diabetic state.
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PMID:Insulin-stimulated calmodulin gene expression in rat H-411E cells can be selectively blocked by antisense oligonucleotides. 776 64

This article reviews the disease process hemochromatosis, which is now recognized as one of the most common genetic disorders. Hemochromatosis is transmitted as autosomal recessive, and occurs in 3% of persons of Anglo-Saxon descent. It is caused by an inappropriate increase in intestinal iron absorption resulting in deposition of excess iron in tissues. Hemochromatosis usually presents in males in their 40s, and females much later. The most frequent initial symptoms are weakness, lassitude, weight loss, and symptoms related to the onset of diabetes mellitus. The classical triad of cirrhosis, diabetes mellitus, and skin pigmentation occurs late in the disease. There is debate over the value of mass screening for the disorder; however, it is recommended that once a case has been identified family members at risk should be screened. Therapy is directed at removing excess iron by phlebotomy. By instituting early therapy, many of the long-term complications, including cirrhosis and hepatoma, can be prevented. It is imperative that physicians learn to recognize early signs and symptoms of hemochromatosis so that treated patients can expect a normal life span with minimal medical intervention.
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PMID:Recognizing genetic hemochromatosis. 784 64


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