Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UNIPROT:P01275 (glucagon)
26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A previous finding that insulin cells do not survive or differentiate in explants of embryonic avian pancreas cultured in collagen gel with a serum-containing medium has provided a model system for identification of conditions favorable for development of these cells. To this end, we here modify the substrate and the medium. The epithelial component of dorsal pancreatic buds of 5-d chick embryos was cultured for 7 d on Matrigel in serum-containing and in serum-free medium, the latter incorporating insulin, transferrin, and selenium. Endocrine cell types were distinguished by immunocytochemistry; insulin cell counts were expressed as a proportion of insulin plus glucagon cells. With serum-containing medium, Matrigel stimulated a significant increase in this proportion as compared with collagen gel--3.1% as against 0.2%; the serum-free medium further increased this proportion to 17.3%. Raising the level of essential amino acids approximately fivefold increased the latter figure somewhat (to 18.9%), but it was more than doubled (to 37.4%) by raising the glucose concentration from 10 mM to 20 mM. Raising the levels of amino acids and glucose simultaneously yielded a lesser increase (to 31.8%). Some cultures grown in collagen gel and serum-containing medium for 7 d were transferred to Matrigel and serum-free medium for a further 7 d. Insulin cell development recovered, indicating that progenitor cells had survived and were stimulated to develop by the improved conditions. This study indicates that components of the biomatrix and the medium (in particular, a raised glucose concentration) are important for the survival and differentiation of embryonic insulin cells.
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PMID:Development of embryonic chick insulin cells in culture: beneficial effects of serum-free medium, raised nutrients, and biomatrix. 946 82

The avian pancreas has three or four lobes and develops from a dorsal and two ventral buds. The cells that will contribute to formation of the dorsal bud are at first located in the mid-dorsal endoderm, those of the ventral buds in the floor of the foregut. The determination of endoderm to form dorsal and ventral bud derivatives occurs before formation of the buds. The highest concentration of endocrine tissue is in the splenic lobe. The lobes contain A and B islets in which glucagon and insulin cells, respectively, predominate. Islets contain somatostatin and pancreatic polypeptide (PP) cells, both of which also occur scattered in the exocrine parenchyma. Pancreatic endocrine cells arise from endoderm: glucagon, insulin, and somatostatin cells differentiate early, PP cells later. To establish culture conditions suitable for avian insulin cells, the epithelial component of dorsal buds of 5-day chick embryos was cultured under various conditions. At the end of 7 days the proportion of insulin cells was determined. In raising the proportion of insulin cells, Matrigel was superior to collagen gel and a serum-free medium (incorporating insulin, transferrin, and selenium) was superior to a serum-containing medium. Modifications to the serum-free medium were tested. Raising the level of glucose or of glucose and essential amino acids increased the proportion of insulin cells. This proportion was also increased by replacement of insulin by insulin-like growth factor-I, whereas addition of transforming growth factor beta1 reduced the proportion. Transfer of explants from poor to favourable culture conditions showed that the improved conditions stimulated quiescent insulin progenitor cells to develop.
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PMID:Morphogenesis and differentiation of the avian endocrine pancreas, with particular reference to experimental studies on the chick embryo. 984 70

We assessed the potential role of all-trans-retinoic acid on the developing chick pancreas, specifically with regard to the proportions of insulin cells. The endodermal component of the dorsal pancreatic bud of 5-d-old chick embryos was cultured on Matrigel. Retinoic acid (10(-6) or 10(-5) M) was added to a standard serum-free medium, Ham's F12 containing insulin, transferrin and selenium (F12.ITS). Control grafts were cultured in F12.ITS alone or in F12.ITS with DMSO (the diluent for retinoic acid). After 7 d the explants were retrieved, freeze-dried, vapor-fixed, and embedded in resin. Endocrine cell types were identified by immunocytochemistry. The numbers of insulin cells were expressed as a proportion of the sum of insulin plus glucagon cells. Retinoic acid had a dose-related effect; the proportion of insulin cells in explants treated with the lower dose of retinoic acid (10(-6) M) was more than twice the proportion of insulin cells in explants treated with the higher dose (10(-5) M) of retinoic acid and more than three times that of the control grafts.
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PMID:The effect of retinoic acid on the proportion of insulin cells in the developing chick pancreas. 1069 Oct 36

Few studies have tried to characterize the efficacy of parenteral support of critically ill infants during short period of intensive care. We studied seventeen infants during five days of total parenteral hyperalimentation. Subsequently, according to the clinical conditions, the patients received nutritional support by parenteral, enteral route or both up to the 10th day. Evaluations were performed on the 1st, 5th, and 10th days. These included: clinical data (food intake and anthropometric measurements), haematological data (lymphocyte count), biochemical tests (albumin, transferrin, fibronectin, prealbumin, retinol-binding protein) and hormone assays (cortisol, insulin, glucagon). Anthropometric measurements revealed no significant difference between the first and second evaluations. Serum albumin and transferrin did not change significantly, but mean values of fibronectin (8.9 to 16 mg/dL), prealbumin (7.7 to 18 mg/dL), and retinol-binding protein (2.4 to 3. 7 mg/dL) increased significantly (p < 0.05) from the 1st to the 10th day. The hormonal study showed no difference for insulin, glucagon, and cortisol when the three evaluations were compared. The mean value of the glucose/insulin ratio was of 25.7 in the 1st day and 15. 5 in the 5th day, revealing a transitory supression of this hormone. Cortisol showed values above normal in the beginning of the study. We conclude that the anthropometric parameters were not useful due to the short time of the study; serum proteins, fibronectin, prealbumin, and retinol-binding protein were very sensitive indicators of nutritional status, and an elevated glucose/insulin ratio, associated with a slight tendency for increased cortisol levels suggest hypercatabolic state. The critically ill patient can benefit from an early metabolic support.
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PMID:Nutritional follow-up of critically ill infants receiving short term parenteral nutrition. 1088 Oct 72

We are interested in the regulation of early pancreatic differentiation, particularly with regard to factors that enhance insulin cell proliferation. Both retinoic acid and insulin-like growth factor 1 (IGF-1) are known to be important in the proliferation and differentiation of insulin cells. Individually, they have the ability to increase the proportion of insulin cells when added to cultures of chick dorsal pancreatic buds. The aim of this study was to define the action of retinoic acid (RA) in combination with IGF-1 on the proportion of insulin cells. The dorsal pancreatic bud of 5-day-old chick embryos was excised and the endodermal component, with minimal adherent mesenchyme, was explanted onto Matrigel. RA (10(-6) M) and IGF-1 (50 ng/ml) were added to Ham's F12 culture medium containing transferrin (5 microg/ml) and selenium (10(-10) M) (F12.TS). Control explants were cultured in F12.TS alone or in F12.TS containing dimethyl sulphoxide (DMSO) [F12.TS (DMSO)]. After 7 days in culture, insulin and glucagon cells were localized immunocytochemically; numbers of insulin cells were expressed as a percentage of insulin plus glucagon cell counts. Addition of RA plus IGF-1 to the medium increased the proportion of insulin cells markedly (23.43%) compared with the proportions in control explants (11.3% with F12.TS (DMSO), 13.2% with F12.TS). This increase represents a more than twofold increase in the proportion of insulin cells over that of control explants.
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PMID:Regulation of embryonic chick insulin cells: effect of retinoic acid and insulin-like growth factor 1. 1134 Feb 60

Previous studies have shown that patients with chronic alcohol ingestion may show a variety of morphological and functional alterations in the small intestine. In this study, we have focused on the neuroendocrine system in the duodenal mucosa in chronic alcoholics; an area little studied. Twenty-three defined chronic alcoholics admitted to the hospital for detoxification underwent clinical examination, followed by upper gastrointestinal endoscopy and blood tests on average 4 days after the most recent alcohol intake. Biopsy specimens were taken from the distal part of the descending duodenum for both immunohistochemical and routine histological examination. The control group consisted of 25 patients referred for upper endoscopy mainly because of dyspepsia (ulcer, reflux type), but who were otherwise healthy. A normal carbohydrate-deficient transferrin and a history of low alcohol consumption (<40 g/week) were required for inclusion in the control group. The tissue specimens were studied using antisera for the following neuropeptides: cholecystokinin, galanin, gastric inhibitory peptide (GIP), glucagon, motilin, neuropeptide Y, pituitary adenylyl cyclase activating peptide, secretin, serotonin, somatostatin, substance P, vasoactive intestinal polypeptide and protein gene product, as a general marker for neurones and cells of the diffuse neuroendocrine system. The density of nerve fibres was evaluated semi-quantitatively and the number of endocrine cells per unit length of mucosa was counted in sections cut perpendicularly to the mucosal surface. All the different peptidergic nerve fibres in the alcohol group showed higher densities than the corresponding controls. However, this was not a statistically significant difference. A slightly significant increase (P = 0.02) in the numbers of glucagon and GIP cells was seen in the alcohol group. Gastrointestinal symptoms were frequently present (87%) in chronic alcoholics. We suggest that chronic alcohol consumption in man may have a general effect on the peptidergic nerve system and some endocrine cell types in the duodenal mucosa.
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PMID:Neuropeptides in the duodenal mucosa of chronic alcoholic heavy drinkers. 1137 57

Early enteral support is believed to improve gastrointestinal, immunological, nutritional, and metabolic responses to critical injury; however, this premise is in need of further substantiation by definitive data. The purpose of this prospective study was to examine the effectiveness and safety of early enteral feeding in pediatric patients who had burns in excess of 25% total body surface area. Seventy-seven patients with a mean percent total body surface area burn of 52.5 +/- 2.3 (range 26-91), percent full thickness injury of 44.7 +/- 2.8 (range 0-90), and age ranging from 3.1 to 18.4 (mean 9.3 +/- 0.5) were randomized to two groups: early (feeding within 24 hours of injury) vs control (feeding delayed at least 48 hours postburn). Nutrient intake was measured daily, indirect calorimetry was performed biweekly, and blood and urine samples were obtained for the assay of cortisol, glucagon, insulin, gastrin, epinephrine, norepinephrine, dopamine, triiodothyronine, tetraiodothyronine, albumin, transferrin, prealbumin, retinol-binding protein, glucose, nitrogen balance, and 3-methylhistidine throughout the study period. Three protocol violations occurred, and two patients were transferred to another hospital; these patients were excluded from the study. No patient in either group experienced tube feeding aspiration. No differences were evident in infection, diarrhea, hospital length of stay, or mortality outcomes. A higher incidence of reportable adverse events coincided with early feeding (22 vs 8%), but this was not statistically significant. The delayed feeding group demonstrated a significant caloric deficit during postburn week (PBW) 1 (P <.0001) and PBW2 (P =.0022). Serum insulin (P =.0004) and triiodothyronine (P =.0162) were higher in the early fed group during PBW1. A decrease in 3-methylhistidine output (suggesting a decrease in protein breakdown) was also evident during PBW1 (P =.0138). No other significant trends in study outcome variables were noted. In conclusion, provision of enteral nutrients shortly after burn injury reduces caloric deficits and may stimulate insulin secretion and protein retention during the early phase postburn. These data, however, do not necessarily reaffirm the safety of early enteral feeding, nor do they associate earlier feeding with a direct improvement in endocrine status or a reduction in morbidity, mortality, hypermetabolism, or hospital stay. Future studies are needed to establish precise feeding implementation times that maximize clinical benefit while minimizing morbidity in the critically injured burn patient.
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PMID:The 2002 Clinical Research Award. An evaluation of the safety of early vs delayed enteral support and effects on clinical, nutritional, and endocrine outcomes after severe burns. 1243 17

Both retinoic acid (RA) and transforming growth factor (TGF)-beta1 are known to be influential in the development of insulin cells. Respectively, they increase and decrease the proportion of insulin cells when added to cultures of embryonic chick dorsal pancreatic buds. The aim of this study was to define the action of RA in the presence of decreased levels of TGF-beta1, as are found in growth factor-reduced Matrigel (GFRM), on the proportion of insulin cells. The endodermal component of 5-d chick dorsal pancreatic buds was explanted on to GFRM. Retinoic acid (10(-6) M) was added to Ham's F12 culture medium containing insulin (5 microg/ml), transferrin (5 microg/ml), and selenium (10(-10) M) (F12.ITS). Control explants were cultured in F12.ITS alone or in F12.ITS containing dimethyl sulfoxide (DMSO). After 7 d in culture, insulin and glucagon cells were localized immunocytochemically; changes in numbers of insulin cells were expressed as a percentage of insulin plus glucagon cells. Medium containing RA or DMSO increased the proportion of insulin cells significantly compared with the proportion in the explants cultured in F12.ITS medium alone.
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PMID:Regulation of the proportion of insulin cells in embryonic chick pancreas: effect of a growth factor-reduced extracellular matrix in combination with retinoic acid. 1461 34

This report describes an enhancement of the signal intensities of proteins and peptides in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). When alpha-cyano-4-hydroxycinnamic acid (CHCA) premixed with human transferrin (Tf) was used as a matrix, the signal intensity of insulin was amplified to more than ten times that of the respective control in CHCA without Tf. The detection limit of insulin was 0.39 fmol on-probe in the presence of Tf, while it was 6.3 fmol in the absence of Tf. The signal intensity of insulin was also enhanced when the CHCA matrix was premixed with proteins other than Tf (80 kDa), such as horse ferritin (20 kDa), bovine serum albumin (BSA, 66 kDa), or human immunoglobulin G (150 kDa). The optimum spectrum of insulin was obtained when the added amount of protein was in the range 0.26-0.62 pmol, regardless of the molecular weight of the added protein. Tf and BSA outperformed the other tested proteins, as determined by improvements in the resulting spectra. When the mass spectra of several peptides and proteins were recorded in the presence of Tf or BSA, the signal intensities of large peptides such as glucagon were enhanced, though those of smaller peptides were not enhanced. In addition, the signal enhancement achieved with Tf and BSA was more pronounced for the proteins, including cytochrome C, than for the large peptides. This enhancement effect could be applied to improve the sensitivity of MALDI-TOFMS to large peptides and proteins.
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PMID:Improved sensitivity for insulin in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry by premixing alpha-cyano-4-hydroxycinnamic acid matrix with transferrin. 1515 Aug 41

Type I diabetes mellitus is caused by an autoimmune destruction of the insulin-producing beta cells. The major obstacle in using transplantation for curing the disease is the limited source of insulin-producing cells. The isolation of human embryonic stem (hES) cells introduced a new prospect for obtaining a sufficient number of beta cells for transplantation. We present here a method for forming immature islet-like clusters of insulin-producing cells derived from hES cells. The protocol consisted of several steps. Embryoid bodies were first cultured and plated in insulin-transferrin-selenium-fibronectin medium, followed by medium supplemented with N2, B27, and basic fibroblast growth factor (bFGF). Next, the glucose concentration in the medium was lowered, bFGF was withdrawn, and nicotinamide was added. Dissociating the cells and growing them in suspension resulted in the formation of clusters which exhibited higher insulin secretion and had longer durability than cells grown as monolayers. Reverse transcription-polymerase chain reaction detected an enhanced expression of pancreatic genes in the differentiated cells. Immunofluorescence and in situ hybridization analyses revealed a high percentage of insulin-expressing cells in the clusters. In addition to insulin, most cells also coexpressed glucagon or somatostatin, indicating a similarity to immature pancreatic cells. Further improvement of this insulin-producing cell protocol may lead to the formation of an unlimited source of cells suitable for transplantation.
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PMID:Differentiation of human embryonic stem cells into insulin-producing clusters. 1515 4


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