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:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Among 30 patients with islet cell neoplasms or hyperplasia who exhibited marked gastric acid hypersecretion and peptic ulceration and/or diarrhea, fasting plasma gastrin concentrations were less than 150 pg/ml in 11 patients, whereas the remaining 19 patients had hypergastrinemia. Plasma extracts from seven of these 11 patients were assayed for acid secretagogue activity in rats. All seven plasma extracts had secretagogue activity that was not found in the plasma extracts of ten patients with ordinary duodenal ulcer disease. Each of the tumor or pancreatic tissue extracts obtained from nine patients exhibited secretagogue activity in rats even though tissue gastrin content was 101.9 pmol (213.8 ng).g-1 or less. The secretagogue activity of the tumor extracts was confirmed in conscious gastric fistula dogs. The tumors' secretagogue activity, in contrast to gastrin, was destroyed by trypsin. It was eluted between porcine motilin and human gastrin I from a Sephadex G-50 (Pharmacia LKB Biotechnology, Inc., Piscataway, NJ) superfine column and was not retained by CM-cellulose, at pH 8.5. Its retention time during reverse phase HPLC on a C18 column also differed from those of G17 and G34. Thus, this secretagogue activity appeared mediated by a small, acidic peptide with a molecular size of about 2000 to 3000 daltons. The present study indicates that plasma and tumor extracts of these 11 patients contain a gastric acid secretagogue activity mediated by a nongastrin peptide. We suggest that what may be a distinct clinical entity associated with endocrine neoplasms of the pancreas should be considered in the face of excessive acid hypersecretion without fasting hypergastrinemia.
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PMID:Ulcerogenic tumor syndrome of the pancreas associated with a nongastrin acid secretagogue. 275 18

Rotaviruses are icosahedral viruses with a segmented, double-stranded RNA genome. They are the major cause of severe infantile infectious diarrhea. Rotavirus growth in tissue culture is markedly enhanced by pretreatment of virus with trypsin. Trypsin activation is associated with cleavage of the viral hemagglutinin (viral protein 3 [VP3]; 88 kilodaltons) into two fragments (60 and 28 kilodaltons). The mechanism by which proteolytic cleavage leads to enhanced growth is unknown. Cleavage of VP3 does not alter viral binding to cell monolayers. In previous electron microscopic studies of infected cell cultures, it has been demonstrated that rotavirus particles enter cells by both endocytosis and direct cell membrane penetration. To determine whether trypsin treatment affected rotavirus internalization, we studied the kinetics of entry of infectious rhesus rotavirus (RRV) into MA104 cells. Trypsin-activated RRV was internalized with a half-time of 3 to 5 min, while nonactivated virus disappeared from the cell surface with a half-time of 30 to 50 min. In contrast to trypsin-activated RRV, loss of nonactivated RRV from the cell surface did not result in the appearance of infection, as measured by plaque formation. Endocytosis inhibitors (sodium azide, dinitrophenol) and lysosomotropic agents (ammonium chloride, chloroquine) had a limited effect on the entry of infectious virus into cells. Purified trypsin-activated RRV added to cell monolayers at pH 7.4 medicated 51Cr, [14C]choline, and [3H]inositol released from prelabeled MA104 cells. This release could be specifically blocked by neutralizing antibodies to VP3. These results suggest that MA104 cell infection follows the rapid entry of trypsin-activated RRV by direct cell membrane penetration. Cell membrane penetration of infectious RRV is initiated by trypsin cleavage of VP3. Neutralizing antibodies can inhibit this direct membrane penetration.
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PMID:Infectious rotavirus enters cells by direct cell membrane penetration, not by endocytosis. 283 76

The gene encoding outer capsid protein VP3 of subpopulations of two animal rotaviruses, simian SA11 and Nebraska calf diarrhea virus (NCDV), was analyzed. Two laboratory strains of simian SA11 rotavirus (SA11-SEM and SA11-FEM) differed with respect to VP3. This dimorphism was indicated by a difference in electrophoretic mobility and a difference in reactivity with anti-VP3 monoclonal antibodies. The overall VP3 amino acid homology between the two SA11 VP3 proteins was 82.7%, whereas the VP3 protein of SA11-FEM was 98.5% homologous in amino acid sequence to NCDV VP3, suggesting that SA11-FEM VP3 was derived by gene reassortment in the laboratory during contamination with a bovine rotavirus. A comparison of the deduced amino acid sequence of the VP3 of two virulent NCDV strains and an attenuated NCDV strain (RIT 4237), revealed only five amino acid differences which were scattered throughout the protein but did not involve the trypsin cleavage sites. Of interest, the VP3 of the standard strain of NCDV which is virulent for cows differed in only one amino acid (position 23, Gln to Lys) from the VP3 of an NCDV mutant which was attenuated both for cows and for children.
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PMID:Comparative analysis of the VP3 gene of divergent strains of the rotaviruses simian SA11 and bovine Nebraska calf diarrhea virus. 284 21

Porcine epidemic diarrhea virus (PEDV) was adapted to serial propagation in Vero cell cultures by adding trypsin to the medium. PEDV-infected cells showed a distinct cytoplasmic fluorescence when examined by a fluorescent-antibody-staining technique. Cytopathic effects, such as vacuolation, formation of syncytia, and fusion of cells, were detected even at passage 1 of the PEDV in Vero cells. Once adapted, the virus induced numerous syncytia containing over 100 nuclei. From virus passage 5 on, all cells forming the monolayer were fused and totally destroyed within 24 h after inoculation. Cell culture-grown PEDV had typical coronavirus morphology when viewed by electron microscopy. Attempts to propagate PEDV in several primary and secondary fetal porcine cell cultures in the presence or absence of trypsin were unsuccessful.
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PMID:Propagation of the virus of porcine epidemic diarrhea in cell culture. 285 74

The sera of four patients with amoebic liver abscess and two patients with diarrhea caused by Entamoeba histolytica were tested on "Western blots" prepared from E. histolytica strains A3, SFL-3 and HK-9 separated by SDS-PAGE. IgG antibodies in the sera from patients with liver abscess were found to react with several "major" (i.e. strongly staining) band of approximate molecular weights 150-250 kD, 100 kD, 80 kD, 60 kD, 35 kD, 30 kD, 20 kD, and 5-15 kD and the 150-250 kD group of bands. A comparison of the patterns of reactivity obtained with these sera and strains A3, SFL-3 and HK-9 would indicate that some of these bands, especially the 5-15 kD groups of bands might carry antigenic determinants specific for individual strains of amoebae. This 5-15 kD group of bands is completely pelleted at 30.000 g and could therefore be associated with the cytoplasmic membrane. The 150-250 kD group of bands consists of smaller subunits of 40-65 kD molecular weight linked by disulfide bridges; the respective proteins are sensitive to digestion with elastase but not with trypsin, and seem to carry antigenic determinants containing sugar residues as evidenced by their sensitivity to treatment with NaJO4.
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PMID:Molecular weight analysis of Entamoeba histolytica antigens recognized by IgG and IgM antibodies in the sera of patients with amoebiasis. 289 43

Rotaviruses were isolated following cell culture of the intestinal contents of four non-diarrheic calves. The four isolates were serially propagated in MDBK and BSC-1 cells in the presence of trypsin and produced rotavirus particles morphologically similar to those found associated with diarrhea. They were antigenically related to the Nebraska calf rotavirus (Norden strain) as investigated by immunofluorescence. Three isolates could be distinguished from the reference Nebraska rotavirus by their thermal stability and/or their differential responses to intestinal neutralizing antibodies. Two isolates produced on BSC-1 cells plaques significantly different in size from the reference strain, No significant genomic variations were detected among the isolates.
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PMID:Distinct rotaviruses isolated from asymptomatic calves. 298 33

Rotaviruses were isolated from intestinal contents obtained from flocks of turkey poults and pheasant poults with diarrhea and from different age groups of chickens showing various signs of intestinal disorders. The incorporation of 5 micrograms trypsin/ml in the inoculum and medium was essential for virus isolation in chicken kidney cells. All isolates were identified as rotaviruses by fluorescent-antibody technique using a National Institutes of Health reference rotavirus antiserum against human rotavirus strain "D," Type 2. Negative-staining and transmission electron microscopy showed the presence of rotavirus particles. Furthermore, polyacrylamide gel electrophoresis pattern of viral RNA segments of our isolates confirmed that they are rotaviruses. Seven-day-old turkey poults could be infected with turkey and chicken rotavirus isolates; in contrast, chicks of the same age were refractory.
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PMID:Isolation and characterization of avian rotaviruses. 299 40

One hundred forty-seven stool specimens from 93 infants younger than four months of age in a Neonatal Intensive Care Unit were tested for rotavirus by the Rotazyme ELISA method (Abbott Laboratories, North Chicago, IL). None of the infants had diarrhea at the time of the testing. Ten of 147 (6.8%) specimens were either low or suspect positive. None had rotavirus by electron microscopy. Excluding the suspect positives, which were negative on retesting, the false positive rate was only 6 of 147 (4.1%). Of five specimens with sufficient material and repeatedly positive tests, heat to 56 degrees C for one-half hour eliminated the binding to the Rotazyme bead but had no effect on the rotavirus positive control. One patient was found to have an extremely high positive Rotazyme test, independently of the survey. No virus was found in this specimen by electron microscopy, and the material responsible for the false positive result was not removed by centrifugation (100,000 X g for one hour), heating to 56 degrees C for one-half hour, trypsin, ether/beta-mercaptoethanol, or dialysis. Thus, false positives were encountered, but the overall rate was acceptably low. Such false positives are likely to result from more than one cause and, depending on results of further study, may be confirmed as false positives by loss of reactivity at 56 degrees C for one-half hour and perhaps lack of binding to a control bead.
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PMID:Rotazyme assay in neonates without diarrhea. Results of screening survey and preliminary analysis of false positive specimens. 300 Jan 63

The name astrovirus was used by Madeley and Cosgrove in 1975 to describe a small round virus (approximately 28 nm diameter) with star-like appearance on electron microscopy. It was first seen in faeces from a few children with gastroenteritis. An aetiological role in gastroenteritis has since been confirmed. The virus causes a mild illness after an incubation period of 3-4 days. Antibody studies indicate that infection is widespread and, in Britain, mainly occurs in the 2-5 year age group. Outbreaks occur in, for example, institutions and paediatric wards. The virus usually spreads by the faecal-oral route but food- or water-borne outbreaks have occurred. Strains of astrovirus have been isolated from many animals including calf, lamb, pig, cat, dog, duck and turkey. The lamb strain can cause gastroenteritis but the bovine strain did not cause diarrhoea in gnotobiotic calves. Infected turkeys have scours, and infection in ducklings causes haemorrhagic hepatitis with a mortality up to 25%. Five human serotypes have been described, all antigenically distinct from the bovine and ovine strains. The human astrovirus does not replicate in conventional tissue cultures but undergoes a non-productive cycle in human embryo kidney cells, and productive replication in the presence of trypsin. It is a positive-strand RNA virus, which is acid stable (pH3), survives at 60 degrees C for five but not 10 minutes and, like the enteroviruses, resists inactivation by alcohols. It has a density of 1.35-1.37 g/ml in caesium chloride.
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PMID:Astroviruses: human and animal. 310 54

Campylobacter jejuni is an important diarrheal pathogen worldwide; the mechanisms by which it causes disease remain unclear. Because of its association with inflammatory diarrhea, we postulated that C. jejuni might produce a cytotoxin similar to that produced by Shigella sp., enterohemorrhagic Escherichia coli O157, or Clostridium difficile. Filtrates of 12 polymyxin-treated isolates of C. jejuni were placed on HeLa cells (sensitive to Shiga toxin cytotoxicity) and Chinese hamster ovary (CHO) cells. Of 12 isolates of C. jejuni tested, 5 killed 50% of the cells at greater than or equal to 1:4 dilutions of filtered suspensions of 10(9) bacteria per ml; killing was similar in HeLa and CHO cells (the CHO cells being insensitive to Shiga cytotoxin). One isolate produced a titer of 1:32 to 1:128. The relative potency in HeLa cells was comparable to that of E. coli strains that produce intermediate amounts of Shiga-like toxin. The other seven strains showed no cytotoxic effect, nor did the control diluents, polymyxin B, or supernatants of C. jejuni not treated with polymyxin B. Sonication also released active cytotoxin, but slightly less well than did polymyxin. The cytotoxic effect was dose dependent. Concentration of the C. jejuni in suspension by 10-fold before treatment with polymyxin B resulted in a 10-fold increase in the 50% cytotoxic dose. The cytotoxin effect was not neutralized by Shiga toxin immune serum against either Shiga-like toxin I or II or by anti-Clostridium difficile antiserum. The C jejuni cytotoxin was partially labile to trypsin (0.25%) and to heating to greater than or equal to 60 degrees C. Cytotoxicity was retained in Scientific Products dialysis tubing D1615-1 (Mr cutoff, 12,000 to 14,000). Some isolates of C. jejuni release a substance lethal to HeLa or CHO cells in vitro that is distinct from Shiga-like or Clostridium difficile toxin. This cytotoxin may contribute to the colonic mucosal invasive process that characterizes C. jejuni enteritis.
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PMID:Production of a unique cytotoxin by Campylobacter jejuni. 365 87


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