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: EC:3.4.24.3 (collagenase)
18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The influence of warm ischemia on pancreatic islet viability was studied by means of 63 isologous transplantations in adult AGUS rats. The pancreases were harvested 0, 20 and 40 min after circulatory arrest. The islets were isolated with collagenase and transplanted intra-portally in known numbers into streptozotocin-diabetic recipients. The islet-dose-metabolic-response relationships in three groups of recipients were compared. No significant difference was found in the quantitative yield. The smallest number of islets which reversed diabetes increased by 25% after a period of warm ischemia regardless of its duration.
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PMID:Viability of the islets of Langerhans after warm ischemia as judged by isologous transplantation. 41 67

This study was designed to determine changes in one of metabolic functions, gluconeogenesis after ischemic renal injury. Right kidneys of SD rats were removed and a vascular clamp was placed across the left renal artery and vein for 0, 10, 30, 60 and 90 min. On 1, 3 and 7 days after the treatment, tubule suspensions were prepared by collagenase treatment of left kidneys and incubated with or without 2 mM pyruvate or malate aerobically. After the incubation, glucose contents were assayed photometrically. Serum creatinine was also determined. In addition, morphological changes were observed under light microscopy to examine the relationship between metabolism and morphology. The tendency of increase of gluconeogenesis was observed on day 1 and 3 after 10, 30, 60 min of ischemic time. On the other hand, gluco-neogenesis decreased significantly on day 1 after 90 min treatment. In contrast, on day 1 and 3 after treatment, serum creatinine levels showed no difference from control at the groups of 10 and 30 min ischemia. Whereas it rose significantly at the group of 60 min ischemia, showing a different tendency from that of the increase of gluconeogenesis. Moreover, morphologic damage was observed on day 1 and 3 after ischemia of 30 and 60 min. The morphologic damage was found more advanced in the corticomedullary region than those of the cortex which has the high gluconeogenic activity and which thus showed relatively limited damage. These results suggest that renal gluconeogenesis is relatively insusceptible to ischemic injury.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Alterations of gluconeogenesis by ischemic renal injury in rats]. 128 6

Kupffer cells and polymorphonuclear leukocytes (PMNs) contribute to the severe reperfusion injury of the liver after ischemia at different time points. The objective of this study was to identify the cellular source(s) of reactive oxygen formation during the PMN-induced injury phase. Kupffer cells and PMNs were isolated from the liver after 45 min of ischemia and 5 h or 24 h of reperfusion using collagenase-pronase digestion and a centrifugal elutriation method. Spontaneous superoxide anion (O2-) formation by large Kupffer cells (basal value 0.65 +/- 0.16 nmol/h/10(6) cells) was increased (up to 550%) during the entire reperfusion period. No enhanced O2- generation by the small Kupffer cell fraction was observed at any time. Control PMNs generated only small amounts of O2- spontaneously (0.25 +/- 0.05 nmol O2-/h/10(6) cells), but hepatic PMNs generated significantly more superoxide: 1.90 +/- 0.58 nmol O2-/h/10(6) cells at 5 h and similarly at 24 h of reperfusion. All cell types were significantly primed for enhanced O2- formation during reperfusion; the priming effect was consistently higher for stimulation with opsonized zymosan (receptor-mediated signal transduction pathway) compared to phorbol myristate acetate (protein kinase C activation). Our data support the hypothesis that PMNs and large Kupffer cells are predominantly responsible for the postischemic oxidant stress during the later reperfusion injury phase after hepatic ischemia in vivo.
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PMID:Superoxide generation by neutrophils and Kupffer cells during in vivo reperfusion after hepatic ischemia in rats. 132 39

This study was designed to determine changes in one metabolic function, gluconeogenesis (GLG), after ischemic renal injury. Tubule suspensions were prepared by collagenase treatment of SD rat kidneys on 1, 3, and 7 days after left renal artery and vein occlusion for 0-90 min and incubated in Krebs-Henseleit buffer with or without 2 mM pyruvate or malate aerobically. Glucose contents were assayed photometrically. On days 1 and 3 after ischemia for longer than 60 min, serum creatinine levels rose significantly. The tendency of increase of GLG was observed on days 1 and 3 after 10-60 min of ischemia. GLG increased significantly on day 1 after 30-min ischemia. On the other hand, GLG decreased significantly on day 1 after 90-min treatment. Morphologic damage was limited to the corticomedullary region on days 1 and 3 after ischemic times of 30 and 60 min. These results suggest that renal GLG is stimulated to supply energy for ATP decrease by ischemia and for further regeneration in extraproximal segments along the nephron.
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PMID:Alterations of gluconeogenesis by ischemic renal injury in rats. 146 98

The objective of this study was to identify the cellular source of the vascular oxidant stress in hepatic ischemia-reperfusion injury in male Fischer rats. Nonparenchymal cells (Kupffer cells, endothelial cells) and neutrophils were isolated from postischemic liver lobes by collagenase-pronase digestion followed by centrifugal elutriation. The spontaneous and stimulated generation of superoxide by these cells were subsequently quantified in vitro. Large Kupffer cells from the postischemic lobes spontaneously generated 300% more superoxide than similar cells from control animals. No difference in spontaneous superoxide formation was found when the small Kupffer cells were compared. No other cells isolated from the postischemic lobes or control liver including neutrophils released any detectable superoxide spontaneously. In contrast, small Kupffer cells and neutrophils from the postischemic liver generated significantly more superoxide after stimulation with phorbol ester or opsonized zymosan than the controls. The considerably higher response with zymosan stimulation compared to phorbol ester indicates a particular priming for a receptor-mediated signal transduction pathway during reperfusion. These studies demonstrate that Kupffer cells are the principal source of the oxidant stress during the initial reperfusion phase after hepatic ischemia. The priming of neutrophils during this time may be an important factor for the later neutrophil-induced injury phase.
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PMID:Superoxide generation by Kupffer cells and priming of neutrophils during reperfusion after hepatic ischemia. 166 25

In an attempt to develop an improved method for preserving the pancreas prior to islet isolation, the effects of warm and cold ischemia were examined on rat pancreases, from which reproducible high yields of islets can be obtained when fresh. Both warm and cold preservation rapidly decreased islet yield. Use of Hanks' or modified Sacks' solution also led to marked decrease in islet yield. After 6 hrs of preservation, the islet yield was 1/5-1/10 of those of fresh pancreases (374 +/- 74, n = 14), and no islets were obtained after 24 hrs of preservation regardless of the preservation solution. Monitoring of ductal pressure during forced injection of Hanks' solution in 6 hrs-preserved pancreas with HBSS showed a significantly earlier and lower peak of pressure than those of fresh pancreases. On the other hand, simple hypothermic preservation after pancreatic ductal distention with collagenase Hanks' solution at the time of harvesting resulted in a significantly higher islet yield up to 6 hours (171 +/- 58, n = 14, P less than 0.01), as compared with conventional methods. The viability of the islets isolated by this method was confirmed by the ability to restore normoglycemia of STZ-induced diabetic B6 mice on transplantation of 400 islets in the renal subcapsular space. These findings indicated that loss of the integrity of the ductal system against forced collagenase injection during cold preservation led to poor distention and digestion of the pancreas, ductal collagenase injection at the time of pancreas harvesting followed by simple preservation is recommended to obtain viable islets from the preserved pancreas.
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PMID:Successful islet isolation from preserved rat pancreas following pancreatic ductal collagenase at the time of harvesting. 196 77

More efficient methods of islet isolation must be developed for islet transplantation to become clinically routine. During collagenase dispersal of human pancreas, an amorphous, viscous, gellike material often develops and entraps large numbers of islets, thereby reducing the yield. When donor human pancreas is minced and treated with collagenase, the gel forms most abundantly if the digestion temperature is less than 35 degrees C and if pH falls below 7.2 +/- 0.2. Gel formation appears to be proportional to warm- or cold-ischemia time and may be related to tissue trauma during collection. Once gel has formed, trapped islets cannot be released by filtration, dilution, DNase, incubation temperature, or pH adjustment. These characteristics suggest that the material is gelatin derived from collagen released enzymatically from pancreatic stroma. We demonstrate that gelation is greatly reduced or eliminated when 1) the incubation medium includes glycerol--a common gelatin solvent--at 5% (vol/vol), 2) the minced tissue-to-total incubation volume ratio is greater than or equal to 1:10, 3) free-islet exposure to pancreatic digestion products is minimized by frequent separation of islets, and 4) collagenase concentration is optimized by titration. Gelation is also minimized by maintaining 5) incubation temperature at 38 +/- 1 degree C and 6) pH in the range 7.7-7.9. Variations in these physical and chemical conditions were analyzed by determining islet yields (stereoscopic microscope counts of serially diluted samples) and by insulin radioimmunoassay of acid alcohol extracts of isolated islets after separation through discontinuous Ficoll gradients. When isolation conditions are optimized as stated, we typically recover 3.3 +/- 1.0 x 10(4) islets/g pancreas, corresponding to greater than 10(6) islets per donor.
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PMID:Factors influencing isolation of islets of Langerhans. 264 35

Warm ischemia (WI) has been shown to be detrimental to organ function following transplantation. We investigated the effect of increasing warm ischemic time (WIT) on islet isolation in rats and dogs. Rat isolations were performed by collagenase digestion and Ficoll purification after increasing periods of WI. Dog isolations were performed after similarly increasing periods of WI by ductal perfusion with collagenase, counts being performed on unpurified tissue. Viability studies were performed on isolated purified rat islets by in vitro perifusion. Islet counts decreased as WIT increased such that after 45 min WI islet counts were only 45.7% of those at 0 WIT (P less than 0.001) in rats and 52.5% in dogs (P less than 0.002). Islet volumes decreased to 47.0% in rats (P less than 0.001) in rats and 52.5% in dogs (P less than 0.002). period. After 90 min WIT islet counts were down to 15.6% (P less than 0.001) in rats and 23.9% in dogs (P less than 0.001) and volumes were down to 16.0% (P less than 0.001) in rats and 10.9% (P less than 0.001) in dogs. The increased release of insulin in response to dextrose stimulation was abolished after only 30 min WIT as assessed by perifusion. This work suggests that if successful islet isolation is to be performed for clinical transplantation, WI during donor pancreatectomy must be minimized, or techniques must be developed to prevent or reverse the ensuing effects.
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PMID:The effect of pancreatic warm ischemia on islet isolation in rats and dogs. 305 26

We studied the effect of nucleus pulposus (NP) on platelet aggregation. Our in vitro experiments showed that NP extract produced platelet aggregation and the addition of collagenase to the NP extract abolished this response. It was further shown that chymopapain did not affect the activity of the extract. We assume that collagen is the active platelet aggregant in the NP extract. Intravascular release of collagen may cause platelet aggregation, vascular obstruction, ischemia, and cord necrosis in a patient with acute transverse myelitis. Intradiskal chymopapain is known to cause transverse myelitis and it is possible that collagen released during the action of the enzyme initiates a similar chain of events.
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PMID:Possible role of collagen in transverse myelitis and chymopapain-induced paraplegia. 396 20

A new digestion chamber was developed which made it possible to isolate 500 islets from the pancreas of one adult rat. The mesh chamber enabled us to remove islets out of the collagenase solution as soon as they are separated from pancreatic tissue. The islet injury due to collagenase was diminished, and the time of warm ischemia during digestion was considerably reduced. With this method it was possible to treat the diabetes successfully in eight of 14 rats. The condition of the remaining six rats was considerably improved, and no animal died due to diabetes during 90 days of surveillance as compared to a 50% death rate in the diabetic control group. A cataract did not occur in any transplanted rat, whereas it was observed in all surviving animals of the diabetic control group. If the complete separation of endocrine and exocrine tissue in a density gradient was abandoned the transplantation results improved significantly.
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PMID:Successful treatment of streptozotocin diabetes of the rat by transplantation of the islets from a single donor pancreas. 621 27


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