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)

One hundred and nineteen isolates of Pseudomonas cepacia, 98 of which were from cystic fibrosis (CF) patients and 21 from environmental and other human sources, were examined for biochemical and exo-enzymatic properties that may contribute to the pathogenicity of this bacterium. The following characteristics were demonstrated significantly more frequently in isolates from CF patients than in control isolates: production of catalase, ornithine decarboxylase, valine aminopeptidase, C14 lipase, alginase and trypsin; reduction of nitrate to nitrite; hydrolysis of urea and xanthine; complete haemolysis on bovine red blood cells; cold-sensitive haemolysis on human red blood cells; greening of horse and rabbit red blood cells. The role of these factors in the pulmonary disease associated with cystic fibrosis is not clear. However, several factors which have been reported previously as being associated with pathogenic processes with other bacteria have now been described in P. cepacia. Additional factors not previously reported as "pathogenicity factors" are also described.
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PMID:Pathogenic factors of Pseudomonas cepacia isolates from patients with cystic fibrosis. 223 77

Information on parents' attitudes towards neonatal screening for cystic fibrosis (CF) and antenatal diagnosis by chorion villus biopsy (CVS) has been derived from a detailed questionnaire administered to parents of CF babies diagnosed early following newborn screening (18 babies), and later on account of clinical criteria (11 babies). Screening was by measurement of immunoreactive trypsin (IRT) on Guthrie card blood spots, which was the basis of the Wales/West Midlands IRT Screening Survey, 1985-1989. Families questioned were from Wales. Most parents supported screening: parents of 15/18 (83%) screened babies and 10/11 (91%) unscreened babies. Following antenatal diagnosis, 15/29 (52%) of families would abort a CF foetus. Neither standard of education nor social class correlated with attitudes to screening or antenatal diagnosis, although these factors were related to the parents' knowledge of CF in general. Several families emphasised the importance of minimal delay between the initial mention of the possibility of CF on IRT testing and confirmation (or otherwise) of the diagnosis. Four mothers acknowledge temporary rejection of their babies during the period of uncertainty or following the procedures of diagnosis, emphasising that neonatal screening for CF can have a psychological impact on the parent-child bonding. Although most families supported neonatal screening for CF, this study underlines some of the difficulties which may be encountered during the procedure of screening for CF by IRT.
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PMID:Attitudes of parents of cystic fibrosis children towards neonatal screening and antenatal diagnosis. 228 19

The use of the dried-blood immunoreactive-trypsin assay for the detection of cystic fibrosis in newborns has been questioned on the grounds that it may fail to identify patients with enough pancreatic function to have normal fat absorption. To investigate this possibility, we assessed pancreatic function in 78 patients identified in a neonatal screening program as having cystic fibrosis. The diagnosis of cystic fibrosis was confirmed by abnormal results on a sweat chloride test. The results of measurements of fecal fat excretion, pancreatic-stimulation tests, and estimations of the serum level of pancreatic isoamylase indicated that 29 of the 78 children (37 percent) had substantial preservation of pancreatic function. These children (median age, four years) had growth that was close to normal and comparable to growth in children with severe pancreatic insufficiency who received oral enzyme therapy. Pancreatic insufficiency subsequently developed in 6 of the 29 patients, at 3 to 36 months of age. We conclude that the serum immunoreactive-trypsin assay used in neonatal screening programs identifies patients with cystic fibrosis who have sufficient pancreatic function to have normal fat absorption and that a substantial proportion of infants identified as having cystic fibrosis are in this category.
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PMID:Pancreatic function in infants identified as having cystic fibrosis in a neonatal screening program. 229 74

Cystic fibrosis (CF) screening by means of immunoreactive trypsin (IRT) lacks specificity: only 1 out of 12 hypertrypsinemic neonates has cystic fibrosis. We propose here to analyse the KM.19 polymorphic site in the dried blood spots as an additional test in hypertrypsinemic neonates. A blind retrospective study of 114 hypertrypsinemic samples has been performed after polymerase chain reaction. Twenty-seven of 37 CF (74%) were homozygous for allele 2 (2-2) and could have been diagnosed on the 15th day of life. Fifty-five percent of the infants tested were homozygous for allele 1 (1-1), a very rare feature in CF, conferring them a probability of being normal of 99.8%. At the moment, this test could be of great help in the CF screening, even better than the search for the delta F508 mutation for which 45.9% of CF patients are homozygous.
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PMID:[A new strategy of neonatal screening for cystic fibrosis. The association of immunoreactive trypsin and molecular biology in dried blood]. 236 11

Meconium specimens from 18 infants with cystic fibrosis (CF) had strong trypsin inhibitory activity (TIA). The same specimen, which contained increased quantities of undigested proteins, had normal concentrations of immunoreactive trypsin (IRT), but deficient trypsin catalytic activity (TCA). TIA was not detected in any specimen from non-CF infants who had high concentration of proteins comparable to that of CF infants. Subjecting meconium supernatant of CF infants to Sephadex G-75 gel filtration revealed that TCA was greatly enhanced in effluents after fractions were activated by porcine trypsin. TCA was present in the same fractions with IRT. The findings suggested that proteases were secreted into the intestinal lumen in CF infants prior to birth. Deficient proteolysis in the disease might be due to the presence of a trypsin inhibitor.
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PMID:Protease inhibitor and defective proteolysis in cystic fibrosis. 244 19

Chronic reserpine treatment (500 micrograms/kg) of the rat results in generalized exocrinopathy, impaired pancreatic secretion, and decreased pancreatic amylase. These characteristics are similar to those in cystic fibrosis and are the basis for use of this experimental model for cystic fibrosis. Pancreatic enzymes adapt to diet, but it is not known whether chronic reserpine treatment affects this response. Due to the malnutrition induced by this treatment, another dose of reserpine was required that would alter pancreatic function but not induce malnutrition in order to evaluate dietary adaptation. Male rats (100-120 g) were injected subcutaneously daily for 7 days with 1) no injection (control); 2) 1.0 ml/kg vehicle or sham (pair fed-sham); or 3) reserpine: 500, 50, or 5 micrograms/kg. Food consumption was comparable among control and reserpine-treated (50 and 5 micrograms/kg) rats and significantly greater (200%) than pair fed-sham and 500 micrograms/kg reserpine-treated rats. Pancreatic amylase, however, was significantly lower in all reserpine-treated rats (500 micrograms/kg, 74%; 50 micrograms/kg, 56%; 5 micrograms/kg, 52%) than in control rats. To evaluate dietary adaptation, control and reserpine-treated (5 micrograms/kg) rats were fed high carbohydrate, high fat or high protein diets. Both groups adapted to these diets with the greatest amylase, lipase, and trypsin activities in high carbohydrate-, high fat-, and high protein-fed rats, respectively. Reserpine-treated rats fed high carbohydrate, however, had significantly lower (64%) amylase activity than high carbohydrate-fed control rats. Although reserpine-treated rats can adapt pancreatic enzymes to diet, the adaptation of amylase to carbohydrate is impaired.
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PMID:Effects of reserpine treatment on dietary adaptation of the rat exocrine pancreas. 245 Dec 6

Trypsin-binding immunoglobulin G (TBIgG) is found in the sera of a high proportion of patients with cystic fibrosis. We previously reported that TBIgG preferentially binds human cationic trypsin rather than trypsin from other animal species. Binding affinity is enhanced by complex formation with bovine pancreatic trypsin inhibitor, which is known to induce characteristic conformational modifications in the active site region of the trypsin molecule. To identify the human trypsin-like antigen associated with TBIgG, we have studied the effects of conformational changes of cationic trypsin induced by limited proteolysis based on competitive binding studies. It is shown that the most likely TBIgG-related self-antigen is an 11,000-dalton fragment that is a cleavage product of the complex formed by trypsin and alpha 1-protease inhibitor. This result emphasizes the occurrence of circulating trypsinogen activation and is interpreted to be a consequence of the protease-antiprotease imbalance, which has been well documented by previous investigators in cystic fibrosis and also in other lung diseases associated with an inflammatory state.
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PMID:Trypsin-binding immunoglobulin G and associated antigen in cystic fibrosis. 247 36

Serum immunoreactive trypsin (IRT) concentrations are elevated in newborn children with cystic fibrosis (CF) and subsequently fall, in most cases, to values below normal. To evaluate the molecular form(s) of IRT present in serum, we have performed serum activation by enterokinase and have measured serum IRT before and after activation. This approach is based on the postulate that enterokinase converts trypsinogen into trypsin, and this trypsin would then be mainly trapped by alpha 2-macroglobulin, thus escaping the assay. This assumption was confirmed in the 28 controls studied, where the mean percentage (+/- S.D.) of IRT recovery after serum activation was 13.7 +/- 2.9. Previous inhibition of alpha 2-macroglobulin by methylamine raised the recovery over 85%, confirming that most of the serum IRT present in controls was in the form of trypsinogen. Identical results were obtained in the serum of 10 obligate heterozygotes and in 57 out of 80 CF patients. In 23 CF patients the mean percentage of IRT recovery after serum activation was 41.6 +/- 17.6. Gel-filtration studies were performed on the sera of the CF patients showing an abnormal increase in the IRT recovery after serum activation. We could demonstrate that IRT was distributed in two fractions: one eluted with the Mr 25,000 protein as usually found in controls and other CF sera, and the other eluted with the Mr 75,000 protein corresponding to a complex of trypsin with alpha 1-proteinase inhibitor. These results show that, in these sera, active trypsin has been directly released in blood. These findings suggest that in some patients with CF, subclinical attacks of acute pancreatitis may occur.
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PMID:Behaviour of serum immunoreactive trypsin after serum activation by enterokinase in normal and cystic fibrosis patients. Evidence of a trypsin-alpha 1-proteinase inhibitor complex in some cystic fibrosis patients. 248 Aug 20

In cystic fibrosis (CF) phosphorylation-dependent activation of outwardly rectifying apical membrane Cl- channels is defective. To further understand regulation of this channel we examined several other mechanisms of channel activation in normal and CF cells. Previous studies have shown that strong membrane depolarization can activate channels in excised cell-free membrane patches. Here we show that such activation is dependent on both the absolute membrane voltage and the duration of depolarization. Moreover, activation was reversible by membrane hyperpolarization. In some cases, excising patches of membrane from the cell caused channel activation, even in the absence of depolarization. However, the frequency of channel activation with patch excision increased when bath temperature was increased from 23 to 37 degrees C. Although the channel remained in the activated state when temperature was reduced to 23 degrees C, subsequent hyperpolarization inactivated the channel. In cell-attached patches, neither depolarization nor increasing bath temperature to 37 degrees C activated channels, suggesting that neither is physiologically important in regulation of the channel. Thus changes in membrane voltage and bath temperature appear to cause a nonenzymatic change in the channel's conformation; the interactions between voltage and temperature suggest that they may affect the same process. To determine if a proteolytic alteration of the channel could also cause activation, we added trypsin to the cytosolic surface of excised membrane patches. Trypsin activated channels, which could not then be inactivated by either hyperpolarization or phosphorylation with PKC, suggesting that trypsin removed or altered a region of the channel involved in inactivation. All of these interventions activated Cl- channels from both normal and CF cells. Thus many aspects of Cl- channel activation are normal in CF; only phosphorylation-dependent activation is defective.
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PMID:Activation of normal and cystic fibrosis Cl- channels by voltage, temperature, and trypsin. 255 52

The mast cell proteases tryptase and chymase have long been known to constitute one-fifth of the total protein in mast cells. However, their biological functions have not been easy to study because of the difficulty in obtaining sufficient amounts of the enzymes to study their biological functions. Recently, we have been fortunate to have available a permanent line of dog mastocytoma cells to purify both enzymes to homogeneity, and we have used the purified enzymes in two ways. First, in a series of biological studies, we have discovered unique and potent actions of the enzymes that may provide important insights into the pathogenesis of diseases such as asthma and cystic fibrosis. Important biological activities are also likely to exist in other tissues. Because of their structures, mast cell proteases are likely to act in proximity to their sites of release. Thus, the presence and amounts of tryptase and chymase in specific loci may play important roles in tissue responses. In diseases such as asthma and cystic fibrosis, there is evidence that the expression of these mast cell enzymes changes, and these changes have important pathogenetic implications. Second, we have begun to perform structural studies of the enzymes. The recent cloning of tryptase by our group should assist in the better understanding of its functions. Crystallography of the pure proteins should provide further insights and could be the basis of rational development of potent and selective drugs that will inhibit their actions.
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PMID:Roles of mast cell proteases in airways. 266 41


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