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Biomedical subjects

N Desai

Publications and source records attributed to N Desai.

At least 91 records · Page 5Linked to original sources
PubMed1990

Heart rate and blood pressure changes during postural change and isometric handgrip exercise in patients with panic disorder and normal controls.

Changes in heart rate (HR) and blood pressure (BP) were measured serially during postural changes and isometric hand grip exercise test (IHT) in 30 patients with panic disorder and 30 normal controls. Though there were no significant differences in the delta increase of HR or systolic or diastolic BP during these tests, the resting supine and standing diastolic BP were significantly higher in panic disorder patients than in controls. The standing mean BP was also significantly higher in panic disorder patients. These findings are suggestive of an increase in adrenergic tone in panic disorder patients.

Adolescent↗
PubMed1989

Increased alpha-adrenergic responsiveness in idiopathic Raynaud's disease.

In our study of 28 patients with idiopathic Raynaud's disease, the patients had significantly greater digital blood flow responses to intraarterial phenylephrine and clonidine than did normal control subjects. There were no group differences in finger blood flow responses to body heating, reflex cooling, digital ischemia, or to intraarterial tyramine or isoproterenol. There were also no group differences in blood pressure or heart rate during any procedure. These results suggest that patients with idiopathic Raynaud's disease have increased peripheral vascular alpha-adrenergic receptor sensitivity and/or density compared with normal persons.

Adult↗
PubMed1989

Possible effect of lactational period on the milk-to-plasma drug concentration ratio in lactating women: results of an in vitro evaluation.

The fat and protein composition of human milk changes dramatically in the first several weeks postpartum. In order to investigate the possible effect of this compositional change on the milk-to-plasma drug concentration ratio (M/P), the following experiment was performed. Milk samples were collected from five healthy lactating women on days 3, 5, 7, and 14 postpartum; blood samples were obtained on these days, as well as on day 1. Serum and skim milk unbound fractions (fp and fm, respectively) and the skim milk-to-whole milk drug concentration ratio (S/M) were determined in vitro in the above samples for diazepam, propranolol, and etretin, an aromatic retinoid. In addition, the composition of these milk and serum samples was also assessed. Using a previously proposed mathematical model for the distribution of drugs between milk and plasma, M/P was calculated from values for fm, fp, S/M, milk pH, and literature values for the pKa values of the compounds. The M/P was calculated for each subject on each day of sample collection. Total serum protein and alpha-1-acid glycoprotein (AAG) levels increased in the first two weeks postpartum. Mean diazepam fp values fell from 0.020 to 0.014 during this period, while propranolol fp values changed inversely with serum AAG levels. Milk whey and total proteins decreased as lactation progressed, but changes in fat levels were not statistically significant. Calculated propranolol M/P increased during the study period, predominately due to changes in milk pH and propranolol S/M.(ABSTRACT TRUNCATED AT 250 WORDS)

Acitretin↗
PubMed1988

A laboratory model for testing agents for hygienic hand disinfection: handwashing and chlorhexidine for the removal of klebsiella.

A model for the laboratory assessment of hygienic hand disinfection is described which closely reproduces handwashing in a ward setting. The model uses a clinically relevant test organism and takes into account the natural antibacterial action of the skin. It also provides a means of measuring any residual antibacterial action after hand disinfection. Using an epidemic multiply-resistant strain of Klebsiella aerogenes K21, 0.5% chlorhexidine in iso-propyl alcohol yielded sterile post-disinfection finger washings more often than 4% chlorhexidine digluconate. Both preparations were more effective than soap and water, and with each residual action was demonstrable. The model is applicable to the laboratory evaluation of hygienic hand procedures and for agents of potential use in defined clinical settings.

1-Propanol↗
PubMed1987

Factors affecting the milk-to-plasma drug concentration ratio in lactating women: physical interactions with protein and fat.

The factors that affect M/P (milk-to-plasma) ratios of several compounds were assessed in vitro using samples collected from four healthy lactating women. Three drugs were studied: diazepam, phenytoin, and propranolol. Serum and skim milk protein binding were determined by equilibrium dialysis at 37 degrees C. Skim-to-whole milk concentration ratios (S/M) were determined after incubation of whole milk at 37 degrees C for 1 h. Free fractions in serum and skim milk, respectively, were 0.013 and 0.334 for diazepam, 0.142 and 0.584 for phenytoin, and 0.107 and 0.699 for propranolol. The S/M values were 0.220, 0.727, and 0.610 for diazepam, phenytoin, and propranolol, respectively. An equation was derived which relates M/P to milk and plasma pH, unbound fractions of drug in skim milk and serum, and S/M. The M/P ratios calculated from in vitro data agreed with published in vivo M/P ratios. The results indicated that milk protein binding and fat partitioning can make a substantial contribution in determining M/P, and predictions of M/P made without considering these factors may be misleading.

Dialysis↗
PubMed1987

PRONUC: a software package for the analysis of protein and nucleic acid sequences.

PRONUC is a menu-driven software package from which a molecular biologist may gain access to a variety of tools for the analysis of protein and nucleic acid sequences. Features include various algorithms for sequence comparisons, secondary structure prediction, sequence manipulation (translation complementation etc.) and finding restriction enzyme cut-sites. The sequences under study can be retrieved from several databases of published sequences or a users sequence(s) can be entered by means of a sequence editor or retrieved from a database constructed by the user. PRONUC comes with a comprehensive manual and on-line help which reflects several years of user feedback and is available for Digital VAX computer systems running the VMS or micro-VMS operating system.

Algorithms↗
PubMed1987

Sex differences in peripheral vascular adrenergic receptors.

Although the incidence of many vascular diseases differs in men and women, sex differences in vascular physiology have not been extensively examined in human in vivo studies. The present study compared finger blood flow responses of normal men and women with brachial artery infusions of adrenergic agonists and with other neurally and nonneurally mediated procedures. In response to phenylephrine and clonidine, men showed significant dose-related vasoconstriction while women did not. In response to isoproterenol, men showed significant dose-related vasodilation while women did not. There were no sex differences in response to intra-arterial nitroglycerin or digoxin or to reactive hyperemia, procedures that do not act through adrenergic receptors. These data show that the sensitivity and/or density of peripheral vascular adrenergic receptors is lower in women than in men. There were no sex differences in response to reflex vasoconstriction or to intra-arterial tyramine, suggesting that neurally released norepinephrine acts at alpha-adrenergic receptors that are spatially removed from those that respond to circulating catecholamines.

Adult↗
PubMed1987

Clinical and biochemical variation and family studies in the multiple acyl-CoA dehydrogenation disorders.

We report clinical and biochemical studies in patients with multiple acyl-CoA dehydrogenation disorders (MAD) and their parents. A severely affected (MAD:S) patient presented with neonatal acidosis leading to death and excreted a wide range of straight- and branched-chain acyl CoA derivatives. Two patients with mild variants of the same disorder (MAD:M) presented with neurologic abnormalities, acidotic coma, and/or poor growth; they primarily excreted ethylmalonate and variable amounts of adipate. Fibroblasts from the MAD:S patient demonstrated severely defective radiolabeled substrate oxidation, while the MAD:M cells had milder oxidative defects. Fibroblasts from two other MAD:M and six other MAD:S patients demonstrated analogous defects in substrate oxidation. As a group, MAD:S cells deficient in electron transfer flavoprotein:ubiquinone oxidoreductase had significantly lower residual oxidative activities than did MAD:S cells deficient in electron transfer flavoprotein. Fibroblasts from the parents of four MAD:S patients oxidized radiolabeled substrates significantly less effectively than did normal infant controls but were indistinguishable from normal adult cells. We found relatively higher residual oxidative activities in maternal than in paternal cells. Amniocytes from a fetus at risk for MAD:S catabolized labeled substrates normally; the infant has been clinically and biochemically normal up to 30 months of age.

Acyl-CoA Dehydrogenase↗
PubMed1986

The use of the Reuter centrifugal air sampler for the estimation of bacterial air counts in different hospital locations.

The convenience and portability of the Reuter centrifugal air sampler (RCS) encouraged us to determine a range of 'expected values' for bacterial air counts in nine hospitals at 13 defined locations. Results were recorded as the number of cfu per strip per 4 min. Bacterial air counts were comparable from hospital to hospital; in operating theatres the overall median RCS counts for air-inlets and in empty operating rooms were 13 and 9.8 cfu per strip per 4 min respectively. For surgical wards the median value was 141 and 180 cfu per strip per 4 min with, and without, air conditioning. Increased counts were readily demonstrated during surgical operations, and during bedmaking in wards. Conversion of RCS counts to cfu m-3 of air usually yielded values higher than those established by other methods. Our findings, however, demonstrate that this instrument may replace some of the applications of the slit sampler and facilitate examination of epidemiological problems.

Air Microbiology↗
PubMed1985

Optimisation of protein synthesis rates in reticulocyte lysates and reconstituted systems.

Means of increasing the very low activity of a reconstituted protein synthesising system from rabbit reticulocytes were investigated. Increasing the concentration of labelled amino acid, addition of polyamines, use of Sepharose-filtered as opposed to centrifuged ribosomes, use of untreated as opposed to gel-filtered cytosol and an increase in ratio of cytosol to ribosomes all contributed to the increase in activity of the system to the point where activity was clearly consistent with initiation taking place. Similar activities could not be attained with rat liver cytosol though rat liver ribosomes incorporated well in reticulocyte cytosol. Incorporation by lysates was also found to be dependent on the concentration of the labelled amino acid added.

Amino Acids↗
PubMed1985

Pancreatic polypeptide in cystic fibrosis.

Patients with cystic fibrosis (CF) and their normal siblings and parents were studied for protein meal-stimulated pancreatic polypeptide (PP) secretion. Patients with CF who had exocrine pancreatic insufficiency did not respond to a protein meal, whereas patients with CF and normal pancreatic function presented relatively well-preserved basal and elevated postmeal PP levels. The siblings responded with relatively lower PP levels compared with the control subjects. Plasma insulin levels were also investigated, and showed sluggish initial-phase but relatively well-preserved insulin responses in the patients with CF. Immunocytochemical and morphometric studies were made of pancreata obtained at autopsy from patients with CF. In the patients younger than 7 years of age, well-preserved islet tissue was disclosed by islet-area morphometry with normal and/or below-normal PP cell counts, whereas patients older than 9 years had relatively less insulin-containing islet tissue and scanty PP cells. Absent PP secretory response in patients with CF who had exocrine pancreatic insufficiency may suggest defects in the PP secretory mechanism. Abnormal PP secretion may be used as an indirect index of pancreatic damage in CF.

Adolescent↗
PubMed1984

Cephalexin for the oral treatment of CAPD peritonitis.

Sixteen episodes of peritonitis in 13 patients undergoing continuous ambulatory peritoneal dialysis (CAPD) were treated with oral cephalexin given at each 6-hourly dialysate exchange. Serial measurements of the antibiotic concentration in serum and dialysate were made in seven cases. Cephalexin levels increased rapidly and by 12 h exceeded 27 mg/l in serum and 20 mg/l in dialysate. Dialysate levels considerably exceeded the minimum bactericidal concentration for organisms considered cephalexin-sensitive and in patients with these the clinical response was usually good. Although dialysate concentrations sometimes reached the minimum inhibitory concentration for organisms considered cephalexin-resistant the clinical response in patients from whom resistant bacteria were cultured was unsatisfactory. Intra-peritoneal antibiotic administration would seem unnecessary in many CAPD patients with peritonitis.

Administration, Oral↗
PubMed1983

Survival of multiply-resistant Klebsiella aerogenes and other gram-negative bacilli on finger-tips.

The survival of various Gram-negative bacilli was evaluated by inoculating the finger-tips of volunteers and determining the number of recoverable organisms in finger washings taken at increasing time intervals up to 60 min. Three epidemic gentamicin-resistant multiply-resistant strains of Klebsiella aerogenes (capsular types K2, K16 and K21) survived better than Pseudomonas aeruginosa, Escherichia coli or non-epidemic antibiotic sensitive klebsiellae of corresponding capsular type. The survival of the epidemic klebsiellae was not altered by curing them of their resistance plasmids. Transfer of their plasmids to E. coli K12 and to sensitive non-epidemic strains of K. aerogenes of corresponding capsular type did not enhance the relatively poor survival of the recipients. We conclude that the enhanced survival on skin of multiply-resistant klebsiellae is not plasmid mediated but may well contribute to the transmissability of these organisms during hospital outbreaks especially when compared with E. coli and Ps. aeruginosa.

Adult↗
PubMed1983

The effects of diazepam and oxprenolol on short term memory in individuals of high and low state anxiety.

1 The effect of oral doses of diazepam (5 mg) and oxprenolol (80 mg) on short term memory of normal individuals stratified for 'state' anxiety levels has been investigated. 2 Normal student volunteers were stratified into high and low anxiety groups on the basis of responses to the Spielberger 'A-state' scale. Subjects were then randomly administered active drug or placebo and given a form of running memory test performed under a variety of conditions in which variable rate of item presentation and articulatory suppression were used. 3 Diazepam significantly reduced the errors of recall in the running memory test in the high anxiety group and produced a distinct separation of response from the low anxiety group under the test conditions of slow item presentation with articulatory suppression. Oxprenolol had no effect on the short term memory test in either high or low anxiety groups in any experimental test situation. 4 These results are compared to previous work in which generally a deleterious effect of diazepam on short term memory in normal volunteers has been reported. The implications of these findings are further discussed in relationship to possible models of memory function.

Adolescent↗
PubMed1980

Nitrous oxide modifies visual responses in the cat retina, striate cortex and superior colliculus.

Extracellular records from 54 single cells in cat optic tract (14), visual cortex (18) and superior colliculus (22), have shown that ventilation of acute animals with a 70%: 30% mixture of N2O/O2 can modify unit responses to visual stimuli. Results indicate that, under nitrous oxide, (a) responses to flashed or moving stimuli may be severely reduced, and frequently abolished. This may be accompanied by either a sharp decrease; or, conversely, by a dramatic increase, in the resting discharge rate; (b) the degree of directional preference of a given unit, in response to a moving visual stimulus, may be substantially modified; (c) the temporal distribution of unit firing may be modified. While about half (57%) of the units in the optic tract were affected by N2O, only 28% of cortical cells showed any N2O-related response modification. The largest effect was observed in the superior colliculus, where 86% of cells were influenced by the anaesthetic. It is suggested that these results might be explained by a selective interference of N2O with serotonergic transmitter mechanisms.

Animals↗