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A Ronai

Publications and source records attributed to A Ronai.

At least 19 recordsLinked to original sources
PubMed1993

Esterase-30 (ES-30) of the house mouse: biochemical characterization and genetics of a new carboxylesterase isozyme linked to cluster-2 loci on chromosome 8.

A new carboxylesterase isozyme (EC 3.1.1.1), designated ES-30, is described in mouse liver. Two phenotypes were distinguished, ES-30A, a possible null type, was found in SPE/Pas and in other lines derived from Mus spretus, and ES-30B was found in BALB/cJ and other laboratory inbred strains. ES-30B is characterized by a distinct electrophoretic band when stained using 5-bromoindoxyl acetate as the substrate. After isolation and purification from other esterases by ion-exchange chromatography and molecular sieving, the molecular mass was estimated by two independent methods to be 62 and 64 kDa, respectively. The activity of ES-30B is higher in adult males than in females and can be stimulated in vivo by testosterone. The distribution of phenotypes on the progeny of a backcross series suggests a separate locus, Es-30, with the allele a for absence and b for presence of the isozyme. Locus Es-30 is shown to be closely linked to Es-2 and to Es-7 of cluster-2 on chromosome 8. The gene order Es-9--Got-2--(Es-2, Es-7, Es-30) is suggested.

Aging↗
PubMed1992

Genetically defined lysosomal acetylesterase EC 3.1.1.6 in the cauda epididymidis of mouse, rat, and man.

After inhibition by bis-p-nitrophenyl phosphate and subsequent staining for esterase using naphthol AS-D acetate as the substrate, a strong lysosomal esterase was demonstrated in the cauda epididymidis of mouse, rat, and man. Owing to its behaviour towards the classifying inhibitors eserine, diisopropyl fluorophosphate, bis-p-nitrophenyl phosphate, and p-chloromercuriphenylsulphonate, this lysosomal esterase was shown to be an acetylesterase (EC 3.1.1.6). Control experiments involving isoelectric focusing revealed that this acetylesterase was identical with the genetically defined homologues ES-17, ES-6, and ES-A4 in mouse, rat, and man, respectively.

4-Chloromercuribenzenesulfonate↗
PubMed1991

Influence of anesthesiology residents' noncognitive skills on the occurrence of critical incidents and the residents' overall clinical performances.

The authors examined residents' clinical performances in five anesthesiology departments in U.S. teaching hospitals. The data were organized by daily use of the Clinical Anesthesia System of Evaluation, which categorizes and quantifies the narrative comments of faculty. The study was designed to identify predictor categories (particular performance characteristics of residents) for the residents' overall performances and their scores in handling critical incidents (those incidents that could or would have caused significant morbidity or mortality had faculty not intervened). More than 9,000 comments made by 163 faculty about 45 residents were analyzed. Residents' noncognitive skills that were predictors of overall performance were Conscientiousness, Management, Confidence, Critical Incidents, and Knowledge. Conscientiousness and Composure predicted two-thirds of the variability in critical incidents' scores. Path analysis verified causal relationships between the hypothesized predictors and critical incidents. For the residents studied, inadequate noncognitive performance in some areas was a powerful (p less than .0005) predictor of overall clinical performance and was related to the occurrence of critical incidents.

Anesthesiology↗
PubMed1988

Lymph esterases of the house mouse (Mus musculus)--I. Identification and possible origins of abdominal lymph esterases.

1. Abdominal lymph was obtained from Mus musculus by cannulation of the thoracic duct: lymph esterases were identified by polyacrylamide gel electrophoresis. Seven known esterases (ES-1, ES-2, ES-5, ES-27, SE-I, SE-II and SE-III) and a newly described activity (SE-IV) were demonstrated, all of which were also present in serum. 2. Electrophoretic staining intensities indicated that the lymph esterases were less concentrated than the corresponding activities in serum, with the single exception of ES-2. This finding was supported by quantitative immunoelectrophoresis of ES-1 and ES-2 (two allozymes each). 3. The jejunum appeared to be the origin of lymph ES-2 by a comparison of organ distribution of the allozymes ES-2B and ES-2D and by monitoring the re-appearance of ES-2 in several organs, serum and lymph after total inhibition in vivo by bis-p-nitrophenyl phosphate.

Abdomen↗
PubMed1988

Lymph esterases of the house mouse (Mus musculus)--II. The role of esterase-2 in fat resorption.

1. Intralipid infusion into the duodenum of Mus musculus was accompanied by changes in lymph and serum concentrations of two esterase isozymes, ES-1 and ES-2. Whereas ES-1 levels declined in both lymph and serum, ES-2 levels increased 5-fold in lymph within 120 min, and fell to a plateau 3- to 4-fold the fasting level; serum levels of ES-2 increased continually. 2. The changes in lymph ES-2 concentrations were paralleled by lymph triglyceride concentration during Intralipid infusion. Genetically determined differences in the concentration of two allozymes, ES-2B and ES-2D, were reflected in differences in lymph triglyceride levels. The lymph triglyceride concentration was strongly correlated with approximately the cube root of the lymph ES-2 concentration for both allozymes. 3. The source of lymph ES-2 during fat resorption was probably an intracellular jejunal pool; serum ES-2 also re-entered the lymph but this fraction was not influenced by fat resorption. 4. Purified chylomicrons possessed no esterase activity; however, it was postulated that ES-2 plays an essential role in fat resorption and is extruded with the primary chylomicrons from the enterocyte.

Animals↗
PubMed1987

Genetic identification of rat liver carboxylesterases isolated in different laboratories.

Six carboxylesterases previously isolated from rat liver microsomes, characterized in Brussels and in Kiel, were compared with genetically defined liver esterases of various reference strains using polyacrylamide gel electrophoresis and isoelectric focusing. The six liver carboxylesterases were identified as alloenzymic forms of ES-3, ES-4, ES-8/ES-10 and ES-15 according to the genetic nomenclature recommended by van Zutphen (Van Zutphen, L.F.M. (1983) Transplant. Proceed. 15, 1687-1688). The genetic and biochemical characteristics of the four isoenzymes are summarized, and their identity with several other drug-metabolizing esterases/amidases and lipases of rat liver endoplasmic reticulum is discussed.

Animals↗
PubMed1987

Inhibition by p-nitrophenylphosphate of acetylcholine release induced by Na+-deprivation.

The effect of p-nitrophenylphosphate (p-NPP) on the release of acetylcholine evoked by drugs and ionic environments known to inhibit Na+, K+-ATPase was studied in isolated cortical slices of rat brain and longitudinal muscle strip of guinea-pig ileum. p-NPP inhibited the release of acetylcholine induced by sodium deprivation provided that the circumstances were in favour of the function of the K+-activated part of ATPase. However, it failed to antagonize the increase in the acetylcholine release elicited by omission of K+ or by administration of ouabain. Therefore it is concluded that the K+-stimulated phosphatase moiety of the Na+, K+-ATPase might be involved in the release of acetylcholine.

Acetylcholine↗
PubMed1987

Esterases in inbred strains of mice with differential cholesterolemic responses to a high-cholesterol diet.

Specific esterase isoenzyme patterns in plasma may be associated with responsiveness of serum cholesterol to dietary cholesterol. In rabbits and rats the presence and absence of a high-mobility, anodal esterase band on electrophoresis have been shown to be associated with hypo- and hyperresponsiveness, respectively. We fed for 28 days male mice of 7 inbred strains either a low-cholesterol, commercial diet or a diet containing 2% (w/w) cholesterol, 0.5% cholic acid and 5% olive oil. Feeding the high-cholesterol diet revealed marked inter-strain differences in the responses of plasma and liver cholesterol; the increases ranged from 21 to 129% and from 10 to 80-fold, respectively. There was no association between esterase isoenzyme patterns in plasma and the sensitivity to the high-cholesterol diet. The mean baseline plasma total esterase activity tended to be positively associated with the absolute response of plasma cholesterol to the high-cholesterol diet (r = 0.56; n = 7), but the positive relationship between the baseline concentration of the ES-1 component in plasma and the cholesterolemic response was stronger (r = 0.84; n = 7; P less than 0.05). The high-cholesterol diet caused a significant increase in plasma total esterase activities in 6 out of the 7 strains. Evidence is presented that the increase in plasma total esterase activity, which was associated with an increase in the activity and concentration of the so-called ES-2 isoenzyme, is the result of an enhanced release of esterases from the intestine, rather than from the liver. A significant, positive correlation was found between the baseline intestinal esterase activity and the cholesterolemic response after cholesterol feeding (r = 0.83; n = 7; P less than 0.05).

Alanine Transaminase↗
PubMed1985

Nonspecific esterases of mammalian testis. Comparative studies on the mouse (Mus musculus) and rat (rattus norvegicus).

Ten different nonspecific esterases in both mouse (Mus musculus) and rat (Rattus norvegicus) testis were identified following the analysis of electrophoretic patterns using genetic, developmental, and biochemical criteria. None of the enzymes were unique to testis, although the pattern of activity was testis specific. The enzymes comprised, in each species, six carboxylesterases (EC 3.1.1.1), one arylesterase (EC 3.1.1.2), one acetylesterase (EC 3.1.1.6), and two butyrylesterases (tentative designation). Cholinesterase (EC 3.1.1.8) was not detected. Individual homology relationships were recognized between the two species for all of these activities, except three of the carboxylesterases; however, these were coded for by homologous gene clusters. Similarities between the two species extended to the developmental course of expression and the modulation of the pattern of activity by the testicular feminization (Tfm) mutation. We describe the effects of the sex reversal (Sxr) mutation in the mouse, as well as the distribution of individual activities between Leydig cells and seminiferous tubules. The results of earlier histochemical studies are interpreted in the light of the present investigation. The correspondence between mouse- and rat-testis esterases suggests that the results could serve as a basis for mammalian testis esterase systems in general.

Acetylesterase↗
PubMed1985

Biochemistry and genetics of esterase-20 (ES-20), a second trimeric carboxylesterase of the house mouse (Mus musculus). I. Purification and characterization of ES-20C1 from male kidney.

ES-20 was isolated from male mouse kidney and purified 350-fold by ion-exchange chromatography, isoelectric focusing, and gel filtration. The resultant product was apparently homogeneous by the criteria of polyacrylamide gel electrophoresis and immunodiffusion and represented a major fraction of male mouse kidney esterase. Sodium dodecyl sulfate gel electrophoresis revealed the presence of a single subunit band, molecular weight 59,500; the molecular weight of the native protein was found to be 179,000. Titration of the active site yielded an equivalent weight of about 175,000. The enzyme was further characterized by its kinetic parameters for the hydrolysis of a series of 4-nitrophenyl esters and was classified as a carboxylesterase (EC 3.1.1.1). ES-20C1 bound to concanavalin A, indicating that it was a high-mannose-type glycoprotein; the role of terminal beta-N-acetylglucosamine residues in the carbohydrate side chains for stabilization of the quaternary structure of the trimer was revealed. Extensive biochemical and immunological similarities to ES-9C supported an earlier suggestion that the Es-9c gene product is a component of the ES-20C1 trimer.

Animals↗
PubMed1983

The making of an anesthesiologist: a review of the American scene.

Many anaesthetists practising in Australia and New Zealand realise that differences exist in the training of their counterparts in the United States. This review attempts to highlight the differences observed by two anaesthetists who have been involved in both systems. Aspects of the American Board of Anesthesiology examination are discussed from this viewpoint.

Anesthesiology↗
PubMed1982

Organ specific expression of esterase-6 in the house mouse, Mus musculus.

Esterase-6 in fresh homogenates of heart muscle and testis of the house mouse shows a two band (C allele) or three band (A allele) pattern in disc electrophoresis. These primary bands generated in series of secondary bands upon lowering the pH of the homogenates, and the secondary pattern, possibly resulting from partial proteolysis, was seen in varying degrees in fresh homogenates from a range of organs. Interrelationships between the primary and secondary bands were demonstrated by isoelectric focusing. The esterase-6 content of twenty different organ homogenates was estimated from electrophoretic gels, and a high level of this enzyme was observed in those organs most actively involved in fat metabolism. The possible participation of esterase-6 in fatty acid utilization is discussed. Similarities between esterase-6 of the house mouse and esterase-4 of the rat were demonstrated, further strengthening the view that these enzymes are homologous.

Adipose Tissue↗
PubMed1982

Purification and characterization of esterase 6A, a trimeric esterase of the house mouse (Mus musculus).

Esterase 6A was isolated from mouse lung and purified 440-fold by ion-exchange chromatography, inverse ammonium sulphate gradient solubilization, gel filtration and isoelectric focusing. The resultant product was apparently homogenous by the criteria of polyacrylamide gel electrophoresis and immunodiffusion, and consisted of the electrophoretic form 6A3. A single species of subunit was present on sodium dodecyl sulphate gel electrophoresis. The molecular weight of the native protein was found to be about 178,000 with a subunit molecular weight of about 60,000. The equivalent weight obtained by active-site titration with diethyl-p-nitrophenyl phosphate was approximately 178,000 g/mol, indicating a functional asymmetry in the trimer. The enzyme was shown to have a high affinity for 4-nitrophenyl hexanoate (Michaelis constant Km = 4.4 mumol/l) with a relatively low catalytic efficiency (catalytic constant kcat = 12 s-1). Esterase 6A was immunologically related to esterase 1 and esterase 9, with which it is genetically closely linked. Further properties of the three esterases were compared.

Animals↗
PubMed1981

Purification and characterization of esterase 1F, the albumin esterase of the house mouse (Mus musculus).

Esterase 1F was isolated from mouse serum and purified by ion-exchange chromatography, isoelectrofocusing, and molecular sieve chromatography. It is considered to be a glycoprotein with an apparent molecular weight of 75 000. The equivalent weight (approximately equal to 77 000 X g/mol) was estimated by titration of the catalytic site with diethyl p-nitrophenyl phosphate. The Michaelis constant Km and the catalytic constant kcat of the enzyme for 4-nitrophenyl hexanoate were determined. Esterase 1F is characterized by its ability to split a wide spectrum of substrates and its relatively low turnover rates towards the substrates tested. It belongs to the isozyme system of carboxylesterase (EC 3.1.1.1) coded for by chromosome 8. Esterase 1F was compared with three other genetically related isozymes, esterase 2, esterase 7 and esterase 9, with respect to some physical and catalytic properties.

Animals↗
PubMed1980

[Non-tropical sprue discrepancy between clinical and biopsy findings. Five years' observation of a case (author's transl)].

After doagnosis and establishment of an appropriate diet a 51-year-old female patient with coeliac disease, who was critically ill in the beginning, became symptomless; nevertheless, a five year follow-up study with mucosa biopsies reveals a persisting villous atrophy with hyperplastic crypts ("flat mucosa"). This discrepancy between clinical and histological findings is discussed and it is emphasized that for coeliac patients a strict adherence to a gluten-free diet and bioptic supervision of therapy are essential. Treatment aimed solely at abolishing the clinical symptoms obviously bears the risk of a persisting symptomless illness and the danger of late complications.

Biopsy↗
PubMed1980

Purification and characterization of esterase 2B of the house mouse, Mus musculus.

Esterase 2B was isolated from mouse kidney and purified about 1300-fold by ion-exchange chromatography and repeated molecular sieve chromatography. The resulting product is apparently homogeneous by the criteria of gel electrophoresis and immunodiffusion. The molecular weight was found to be 57 000. The equivalent weight (54 000) was estimated by titration of the catalytic site by bis(p-nitrophenyl) phosphate. The Km constants of seven 4-nitrophenyl esters of n-fatty acids (C2-C8) were determined. The logarithm of Km decreases linearly with increasing number of C atoms of the fatty acid moiety. Concurrently, the free enthalpy delta G'0 of the enzyme-substrate complex increases by about 2.46 kJ/mol CH2 group. Similar results are obtained when a series of esters of 8-hydroxyquinoline were used as substrates.

Animals↗
PubMed1979

Esterase-7, a common constituent of numerous mouse tissues.

1. Electrophoretic and staining techniques for the relatively specific demonstration of esterase-7 in mouse tissues are described. Esterase-7 was found to be a common constituent of most mouse tissues. 2. The electrophoretic polymorphisms determined by three alleles a, b and c were studied in nine mouse strains. 3. The banding pattern of esterase-7 is being described and the isoelectric points of the allelic bands are being estimated. 4. Recombination studies on a further 129 animals confirmed that the Es-7 locus is tightly linked to Es-2 and Es-11. 5. Esterase-7 precipitates with antiesterase-2 from the rabbit. 6. It differs from esterase-2 by its individual substrate preference and by its susceptibility to inhibition by acylating agents.

Alleles↗