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Biomedical subjects

R Patel

Publications and source records attributed to R Patel.

At least 379 records · Page 21Linked to original sources
PubMed1981

Stereospecificity and other properties of a novel secondary-alcohol-specific alcohol dehydrogenase.

NAD-dependent alcohol dehydrogenase from the methanol-grown Methylcoccus sp. CRL M1 (type I membrane), Methylosinus trichosporium OB3b (type II membrane), Methylobacterium organophillum CRL 26 (type II membrane, facultative methylotroph). Pseudomonas sp. ATCC 21439, and Pichia pastoris Y-55 are secondary-alcohol-specific and that from P. pastoris Y-7556 is not. This novel secondary-alcohol-specific alcohol dehydrogenase (secondary-alcohol dehydrogenase) has been purified from methanol-grown Pseudomonas sp. ATCC 21439. Secondary-alcohol dehydrogenase shows a single protein band on acrylamide gel electrophoresis and has a molecular weight of 95000. It consists of two subunits of Mr 48000 daltons and two atoms of zinc per molecule of enzyme protein. It oxidizes secondary alcohols, notably 2-propanol and 2-butanol. Primary alcohols are not oxidized. The pH and temperature optima for secondary-alcohol dehydrogenase are 8--9, and 30--35 degrees C, respectively. The activation energy calculated is 82.8 kJ. Secondary-alcohol dehydrogenase also catalyzes the reduction of methyl ketones to their corresponding 2-alcohols in the presence of NADH (a reverse reaction). The Km values at 25 degrees C in the forward reaction for 2-butanol, (2R)-(-)-butan-2-ol, and NAD, and in the reverse reaction for 2-butanone and NADH are 2.5 x 10(-4) M, 1.6 x 10(-4) M, 11 x 10(-5) M, 1.98 x 10(-4) M, and 2.1 x 10(-6) M, respectively. The secondary-alcohol dehydrogenase activity was inhibited by metal-chelating agents and by strong thio reagents such as p-hydroxymercuribenzoate and 5,5'-dithiobis(2-nitrobenzoic acid). The substrate specificity, and mobility on gel electrophoresis of secondary-alcohol dehydrogenase and primary-alcohol dehydrogenases are compared. Secondary-alcohol dehydrogenase oxidizes preferentially the (-)-2-butanol. This is different from primary-alcohol dehydrogenase from bakers' yeast which oxidizes only the (+)-2-butanol. This may be explained in terms of the structure of the enzymes.

Alcohol Dehydrogenase↗
PubMed1981

Substrate specificity and stereospecificity of nicotinamide adenine dinucleotide-linked alcohol dehydrogenases from methanol-grown yeasts.

Nicotine adenine dinucleotide-linked primary alcohol dehydrogenase and a newly discovered secondary alcohol dehydrogenase coexist in most strains of methanol-grown yeasts. Alcohol dehydrogenases from methanol-grown yeasts oxidize (--)-2-butanol preferentially over its (+) enantiomorph. This is substantially different from alcohol dehydrogenases from bakers' yeast and horse liver.

Alcohol Oxidoreductases↗
PubMed1981

Histocompatibility antigens in black patients with essential hypertension.

Essential hypertension is a common disorder with potentially life-threatening sequelae. Hypertension among black persons may have characteristics different from hypertension among white persons. It has been estimated that up to 60% of population variance in blood pressure may be attributable to genetic differences. We studied the distribution of HLA antigens in 100 black hypertensives and 100 normotensive controls. Hypertension was not significantly associated with any of the 25 HLA antigens identified. We conclude that HLA-A and HLA-B locus antigens are not associated with essential hypertension in the black patient.

Adult↗
PubMed1980

Myoglobinuric acute renal failure in phencyclidine overdose: report of observations in eight cases.

Eight cases of myoglobinuric acute renal failure that developed following exposure to phencyclidine were seen in the emergency department of the Martin Luther King Jr. General Hospital during a period of 36 months. All eight survived with complete recovery of renal function. Dialysis was necessary in three patients. Acute renal failure is an uncommon complication of phencyclidine abuse.

Acute Kidney Injury↗
PubMed1980

Comparative echocardiographic features of conditions presenting with symptomatic pulmonary hypertension and right ventricular hypertrophy in early infancy.

Echocardiographic dimensions in infants (less than 2 months) with pulmonary hypertension, associated with coarctation of the aorta in 21, total anomalous venous return in 10, and left-to-right shunts in 14 were compared with 10 infants with respiratory distress syndrome, seven with transient tachypnoea of the newborn, 20 normal children, and with each other. Distinguishing features of total anomalous pulmonary venous return were very significantly lower left atrial and left ventricular dimensions. Right ventricular enlargement was maximal in patients with coarctation of the aorta and total anomalous pulmonary venous return. Left ventricular end-diastolic dimension in coarctation of the aorta was not significantly different from normal but the left ventricular end-systolic dimension was significantly lower, suggesting a hypercontractile left ventricle. Similar findings were observed in patients with left-to-right shunts. M-mode echocardiograms are hence valuable in differentiating conditions which may present with intractable congestive cardiac failure in the newborn and also distinguishing them from common respiratory disease of the neonate.

Cardiomegaly↗
PubMed1980

A midsystolic ejection click.

A patient of faintly marfanoid habitus with left venticular failure, aortic regurgitation, and rate-related left bundle-branch block was found to have a midsystolic click and echocardiographic findings suggestive of mitral valve prolapse; however, the click did not move earlier in systole in response to head-up tilt or atrial pacing. Cardiac catheterization and angiocardiographic studies revealed severe left ventricular dysfunction out of proportion to the moderate amount of aortic regurgitation observed on aortographic study. Mitral valve prolapse was not confirmed by left ventriculographic study. Intracardiac phonocardiographic and catheter-tip manometric studies identified the click as being aortic in origin, ejection in timing, and midsystolic, rather than early systolic, because of delayed aortic valve opening related to left ventricular dysfunction and delay in conduction.

Adult↗
PubMed1979

Serum angiotensin converting enzyme activity in patients with chronic renal failure on long term hemodialysis.

Serum angiotensin converting enzyme activity was assayed by a spectrofluorometric method in 19 patients with chronic renal failure on long term hemodialysis and 19 control subjects. Converting enzyme activity was increased in 11 of 19 (58%) patients compared with the controls (p less than 0.005). There was no correlation between serum converting enzyme activity and plasma renin activity or blood pressure in the patients. Possible mechanisms responsible for the increased converting enzyme activity are discussed.

Adult↗
PubMed1979

The HLA antigens and ABO blood groups in an American Black population with mitral valve prolapse.

A total of 42 American Black patients with mitral valve prolapse and 194 healthy individuals of similar ethnic background were tested for the distribution of various HLA antigens and ABO blood groups. The most significant result was an increased frequency of Bw35 in patients (74%) as compared with controls (39%), with a P value of less than 0.0001; the relative risk was 4.45.

ABO Blood-Group System↗
PubMed1979

Microbial oxidation of gaseous hydrocarbons: epoxidation of C2 to C4 n-alkenes by methylotrophic bacteria.

Over 20 new cultures of methane-utilizing microbes, including obligate (types I and III) and facultative methylotrophic bacteria were isolated. In addition to their ability to oxidize methane to methanol, resting cell-suspensions of three distinct types of methane-grown bacteria (Methylosinus trichosporium OB3b [type II, obligate]; Methylococcus capsulatus CRL M1 NRRL B-11219 [type I, obligate]; and Methylobacterium organophilum CRL-26 NRRL B-11222 [facultative]) oxidize C2 to C4 n-alkenes to their corresponding 1,2-epoxides. The product 1,2-epoxides are not further metabolized and accumulate extracellularly. Methanol-grown cells do not have either the epoxidation or the hydroxylation activities. Among the substrate gaseous alkenes, propylene is oxidized at the highest rate. Methane inhibits the epoxidation of propylene. The stoichiometry of the consumption of propylene and oxygen and the production of propylene oxide is 1:1:1. The optimal conditions for in vivo epoxidation are described. Results from inhibition studies indicate that the same monooxygenase system catalyzes both the hydroxylation and the epoxidation reactions. Both the hydroxylation and epoxidation activities are located in the cell-free particulate fraction precipitated between 10,000 and 40,000 x g centrifugation.

Alkenes↗
PubMed1979

Microbial oxidation of gaseous hydrocarbons: production of methyl ketones from their corresponding secondary alcohols by methane- and methanol-grown microbes.

Cultures of methane- or methanol-utilizing microbes, including obligate (both types I and II) and facultative methylotrophic bacteria, obligate methanol utilizers, and methanol-grown yeasts were isolated from lake water of Warinanco Park, Linden, N.J., and lake and soil samples of Bayway Refinery, Linden, N.J. Resting-cell suspensions of these, and of other known C1-utilizing microbes, oxidized secondary alcohols to their corresponding methyl ketones. The product methyl ketones accumulated extracellularly. Succinate-grown cells of facultative methylotrophs did not oxidize secondary alcohols. Among the secondary alcohols, 2-butanol was oxidized at the highest rate. The optimal conditions for in vivo methyl ketone formation were compared among five different types of C1-utilizing microbes. Some enzymatic degradation of 2-butanone was observed. The product, 2-butanone, did not inhibit the oxidation of 2-butanol. The rate of the 2-butanone production was linear for the first 4 h of incubation for all five cultures tested. A yeast culture had the highest production rate. The optimum temperature for the production of 2-butanone was 35 degrees C for all the bacteria tested. The yeast culture had a higher temperature optimum (40 degrees C), and there was a reasonably high 2-butanone production rate even at 45 degrees C. Metal-chelating agents inhibit the production of 2-butanone, suggesting the involvement of metal(s) in the oxidation of secondary alcohols. Secondary alcohol dehydrogenase activity was found in the cell-free soluble extract of sonically disrupted cells. The cell-free system requires a cofactor, specifically nicotinamide adenine dinucleotide, for its activity. This is the first report of a nicotinamide adenine dinucleotide-dependent, secondary alcohol-specific enzyme.

Butanols↗
PubMed1979

Symptomatic hypomagnesemia associated with gentamicin therapy.

A 57-year-old male developed hypomagnesemia, hypokalemia and hypocalcemia during the course of repeated gentamicin therapy. Renal wasting of magnesium and potassium was demonstrated. Associated endocrine abnormalities included decreased level of serum immunoreactive parathyroid hormone and increased levels of plasma renin and aldosterone. Our findings are compared to those previously reported by other investigators.

Adult↗
PubMed1978

Cytomegalovirus infections in renal allograft recipients: correlative studies with histocompatibility antigens.

We studied 32 renal allograft recipients in order to determine whether or not any correlation could be demonstrated between the HLA and development of cytomegalovirus infection. There was a positive stastical correlation (P less than 0.01) of the development of cytomegaloviraemia and the number of HLA antigens mismatched in the recipient. There was no correlation between specific HLA antigens and predisposition to develop cytomegalovirus infection. The implication of our observations with regard to the pathogenesis of cytomegalovirus infection in renal allograft recipients is discussed.

Adult↗