Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous work has demonstrated that adult newt cardiac myocytes possess a proliferative ability in response to an experimentally induced injury, in vivo. This study describes an in vitro model in which the proliferative events of the adult cardiac myocyte may be studied. Ventricles were minced and then enzymatically dissociated in a Ca++- and MG++-free salt solution containing 0.5% trypsin and 625 U/ml of CLS II collagenase for 8 to 10 hours at 25 degrees C. Enzyme digests were preplated and then cultured on bovine corneal endothelial-derived basement membrane "carpets" in either serum-free or serum-supplemented modified Leibovitz's medium for up to 30 days. Light and transmission electron microscopic characterization demonstrated that a majority of the myocytes underwent an initial period of disorganization characterized by a "rounding up" of the cell and a loss of myofibrillar organization. Once the myocytes had attached to the culture substratum they began to spread out, underwent a reassembly of their contractile elements, resumed spontaneous contractions, and demonstrated ultrastructural evidence of protein synthesis. Mitosis was observed in several myocytes 8 to 15 days following isolation. In 15-day serum-supplemented and serum-free cultures, 6.5% +/- 0.9% and 8.1% +/- 1.4% of the myocytes were binucleated, respectively. These results demonstrate that adult newt ventricular myocytes can be successfully placed into primary culture and are capable of undergoing mitosis. This work may be considered as a foundation for future investigations which will focus on the mechanisms which control cardiac myocyte proliferation.
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PMID:Primary cell culture and morphological characterization of ventricular myocytes from the adult newt, Notophthalmus viridescens. 265 85

Hypocalcemia frequently occurs in acute pancreatitis (AP), but its pathogenesis remains unknown. Since AP is often accompanied by acute alteration in the structure and function of cellular membranes, we investigated whether hypocalcemia associated with AP can be explained by acute translocation of Ca from extracellular to intracellular compartments. AP was induced in dogs by injection of autologous bile into the pancreatic duct, and in rats by controlled infusion of artificial bile containing Na-taurochlorate, Keflin, and trypsin into the cannulated bile duct. Plasma Ca, Mg, amylase, and PTH concentrations were determined in the serial samples. Tissue [Ca] and [Mg] were determined in pancreas, liver, kidney, and abdominal wall muscle biopsies obtained immediately before and 24 h after induction of AP in dogs or 2 h following induction of AP in rats to evaluate the temporal correlation between hypocalcemia and excessive intracellular Ca accumulation in soft tissues. Hypocalcemia (p less than 0.001) and hyperamylasemia (p less than 0.01) occurred within 6 h of AP in dogs, and persisted throughout. Plasma [Mg] was lowered and PTH activity was elevated at 6 and 18 h, and returned to a near normal level by 24 h. Concomitant with persisting hypocalcemia and lower ultrafilterable plasma [Ca2+], tissue [Ca] was significantly elevated in pancreas (71%), liver (24%), and abdominal muscle (112%), but was depleted in kidney by 25%. Pancreas biopsy following AP revealed histological signs of fulminant pancreatitis. [Mg] was depleted only in the pancreas (18%) and remained unaltered in other tissues. No significant changes were noted in the sham-operated animals. The observed temporal correlation between profound hypocalcemia and acute excessive intracellular Ca accumulation in soft tissues strongly suggests that hypocalcemia in AP may be precipitated by leaky-plasma-membrane-mediated excessive intracellular Ca accumulation. Similar data together with significantly reduced cellular energy charge (p less than 0.01) obtained from AP rats provided additional support to our hypothesis.
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PMID:Mechanism of calcium and magnesium translocation in acute pancreatitis: a temporal correlation between hypocalcemia and membrane-mediated excessive intracellular calcium accumulation in soft tissues. 339 93