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M Desai

Publications and source records attributed to M Desai.

At least 19 recordsLinked to original sources
PubMed1999

High-resolution genotyping of Streptococcus pyogenes serotype M1 isolates by fluorescent amplified-fragment length polymorphism analysis.

We have used fluorescent amplified-fragment length polymorphism (FAFLP) analysis to subtype clinical isolates of Streptococcus pyogenes serotype M1. Established typing methods define most M1 isolates as members of a clone that has a worldwide distribution and that is strongly associated with invasive diseases. FAFLP analysis simultaneously sampled 90 to 120 loci throughout the M1 genome. Its discriminatory power, precision, and reproducibility were compared with those of other molecular typing methods. Irrespective of disease symptomatology or geographic origin, the majority of the clinical M1 isolates shared a single ribotype, pulsed-field gel electrophoresis macrorestriction profile, and emm1 gene sequence. Nonetheless, among these isolates, FAFLP analysis could differentiate 17 distinct profiles, including seven multi-isolate groups. The FAFLP profiles of M1 isolates reproducibly exhibited between 1 and more than 20 amplified fragment differences. The high discriminatory power of genotyping by FAFLP analysis revealed genetic microheterogeneity and differentiated otherwise "identical" M1 isolates as members of a clone complex.

Antigens, Bacterial↗
PubMed1998

Ciprofloxacin as a therapeutic modality in pediatric burn wound infections: efficacious or contraindicated?

BACKGROUND: Food and Drug Administration regulations state that ciprofloxacin hydrochloride may cause arthropathies. For this reason, such therapy is contraindicated in the pediatric population. However, several studies in children with cystic fibrosis have found the drug to be efficacious. Our hypothesis was that ciprofloxacin treatment is justified in the case of multiresistant organisms in burn populations. DESIGN: During a 4-year period (January 1, 1993, to December 31, 1997) we treated 56 of our pediatric burn patients with ciprofloxacin when cultures proved resistant to other antibiotics. The burn area was 65% of the total body surface area. The average patient age was 8.4 years. Of the 56 patients who received ciprofloxacin, 50 received the recommended dose. Biopsy specimens were assessed for quantitative bacteriology and antibiotic sensitivity. Radiologic review was conducted to examine for arthropathy. RESULTS: All patients showed unequivocal reduction in quantitative bacterial counts, and susceptibility to ciprofloxacin remained stable without the development of resistance. Of the 56 patients treated, 42 had a major reduction in their quantitative wound biopsies from 10(6) to less than 100 colonies per gram of tissue, while the remaining 14 were observed to have a 2- to 3-log decrease. No arthropathy was detected in any of the 56 patients receiving ciprofloxacin. Review of the patients' charts showed no documented adverse events associated with the use of ciprofloxacin. All patients survived their thermal injury and the complications associated with it without any untoward problems or complications of arthropathy. CONCLUSION: On the basis of these data, ciprofloxacin therapy in the treatment of immunosuppressed pediatric burn patients is efficacious and does not cause arthropathy.

Adolescent↗
PubMed1998

Generation of a reproducible nutrient-depleted biofilm of Escherichia coli and Burkholderia cepacia.

An in vitro method of growing bacteria as a defined nutrient-depleted biofilm is proposed. The medium was defined nutritionally in terms of the quantitative composition and by the total amount of nutrient required to achieve a defined population size. Escherichia coli and Burkholderia cepacia were incubated on a filter support placed on a defined volume of solid medium. The change of biomass of the biofilm population was compared with the change in a planktonic culture. The size of the population in stationary phase was proportional to the concentration of limiting substrate up to 40 mumol cm-1 glucose for E. coli and up to 2.7 x 10(-9) mol cm-2 iron for B. cepacia. Escherichia coli growing exponentially had a growth rate of mu = 0.30 h-1 in a biofilm and mu = 0.96 h-1 in planktonic culture. The growth rate, mu, for exponentially growing B. cepacia in a biofilm was 1.12 h-1 and in planktonic culture 0.78 h-1. This method allows the limitation of the size of a biofilm population to a chosen value.

Biofilms↗
PubMed1998

A clinicogenetic analysis of six Indian spinocerebellar ataxia (SCA2) pedigrees. The significance of slow saccades in diagnosis.

Clinical revaluation and genetic analysis of six Indian pedigrees, segregating autosomal dominant cerebellar ataxia, slow saccades and peripheral neuropathy, has been undertaken, and expansion at the spinocerebellar ataxia 2 (SCA2) locus was confirmed in 14 affected family members. These families became available from 31 phenotypically similar families seen over the years. In common with other neurodegenerative disorders resulting from expansion of a CAG trinucleotide repeat motif, an inverse correlation between repeat size and age at onset and severity is observed, although the size range (36-45 repeat units) for the expanded alleles is comparatively limited. Saccadic velocity was reduced in all our patients, even in the early stages of the disease. The observation of slow saccades in affected individuals has been proposed previously as an important diagnostic criterion serving to distinguish the SCA2 phenotype. This is now confirmed in a retrospective study of the clinical literature, facilitated by the cloning of the SCA2 gene and the subsequent genetic analysis of families segregating this phenotype. We therefore argue that the clinical appraisal of 'ophthalmoplegia' be subject to more precise definition, as differentiation between the various types of ocular dysfunction can be an important adjunct to diagnosis.

Adolescent↗
PubMed1998

Increasing resistance of planktonic and biofilm cultures of Burkholderia cepacia to ciprofloxacin and ceftazidime during exponential growth.

The change in resistance of Burkholderia cepacia to ceftazidime and to ciprofloxacin during the exponential phase and up to the onset of stationary phase was assessed along the growth curve in batch culture. B. cepacia was grown in planktonic culture and in a biofilm on a membrane support. Resistance increased progressively during the exponential phase, being increased by ten-fold about every four generations. Bacteria grown in a biofilm were about 15 times more resistant than equivalent planktonic-grown bacteria. The growth rate was not the key factor for the development of resistance. The growth phase and the mode of growth have a fundamental impact on the susceptibility of B. cepacia towards antimicrobial agents. Bacteria growing at the same rate may differ greatly in their resistance to antimicrobial agents.

Animals↗
PubMed1998

Effects of protein restriction in early life on growth and function of the gastrointestinal tract of the rat.

BACKGROUND: Undernutrition during early life may have both immediate and later consequences. This study was undertaken to measure the long-term effects of perinatal undernutrition on the growth and function of the gastrointestinal tract. METHODS: Pregnant rats were assigned to one of four groups that received isocaloric diets restricted in protein during pregnancy or lactation and during both or neither. Thereafter, their pups were followed until aged 1 year. RESULTS: At 21 days the body weights of the young of those born of dams with postnatal protein restriction were halved, with comparable reductions in the weights of the stomach and caecum, compared with those of control animals. The lengths of the small and large intestines and mucosal weights of the foregut were also significantly reduced. Lactase activities were significantly increased and sucrase and maltase activities significantly reduced. By 42 days all the effects were less marked, and at 1 year the dimensions of the organs of the gastrointestinal tract and the composition and enzyme levels of the mucosa were all insignificantly different relative to body weight. CONCLUSIONS: Prenatal protein restriction alone had no significant long-term negative effects on body weight, growth, or mucosal hydrolase activity of the gastrointestinal tract. Postnatal protein restriction had a marked effect on these indices in early life and delayed the changes in mucosal hydrolases usually seen at weaning. In contrast with other organs and their functions, long-term growth of the gut and activity of small intestinal hydrolases are preserved in the face of perinatal protein restriction.

Animals↗
PubMed1998

Effects of insulin on wound healing.

BACKGROUND: Insulin plus glucose, given for 7 days to hypermetabolic burn patients, has been shown to stimulate limb protein anabolism. We hypothesized that insulin plus glucose given to burn patients would also stimulate wound healing. METHODS: Six patients with burns >40% total body surface area were randomized to receive insulin or placebo in a crossover study during the healing of their first and second donor sites. Insulin treatment was titrated at 25 to 49 U/h to achieve a plasma insulin level of 400 to 900 microU/mL for 7 days. Patients receiving insulin received dextrose 50 at 20 to 50 mL/h, titrated to maintain euglycemia. Donor-site biopsies were taken at 7 days and evaluated by three observers blinded to the treatment. RESULTS: The mean (+/-SD) donor-site healing time was reduced from 6.5 +/- 1.0 days with placebo to 4.7 +/- 1.2 days during insulin infusion (p < 0.05). Laminin showed intense staining along the basal lamina and blood vessels. Collagen type IV staining also increased after insulin therapy compared with placebo. CONCLUSION: Data indicate that high doses of insulin and glucose can be safely administered to massively burned patients to improve wound matrix formation.

Adolescent↗
PubMed1998

Long-term psychosocial adaptation of children who survive burns involving 80% or greater total body surface area.

OBJECTIVE: To examine the psychosocial adjustment of survivors of massive pediatric burn injuries, the change in adjustment across time, and the impact on parents. BACKGROUND: Patients/parents were assessed at regular intervals postburn using standardized tests of adjustment. Patients who could not be included in standardized longitudinal assessments were administered questionnaires by mail/telephone. METHODS: The Child Behavior Checklist, the Teacher Report Form, the Youth Self Report Form, and the Parenting Stress Index were utilized to assess adjustment. RESULTS: On all objective measures, the group of survivors and their parents were within normal limits. Adjustment neither improved nor deteriorated over time. CONCLUSION: Children who survive massive burn injuries can achieve positive psychosocial adaptation.

Activities of Daily Living↗
PubMed1998

Fluorescent amplified-fragment length polymorphism analysis of an outbreak of group A streptococcal invasive disease.

Fluorescent amplified-fragment length polymorphism (FAFLP) analysis was carried out for an outbreak of group A streptococcal (GAS) invasive disease. Streptococcal genomic DNAs were digested with endonucleases EcoRI and MseI, site-specific adaptors were ligated, and PCR amplification was carried out with an EcoRI adaptor-specific primer labelled with fluorescent dye. Amplified fragments of up to 600 bp in size were separated on a polyacrylamide sequencing gel which contained internal size markers in each lane. These data were automatically scanned and analyzed, fragments were precisely sized (+/-1 bp), and electropherograms were generated for each genome with GeneScan 2.1 software. All isolates were compared in this way. Among 27 GAS isolates examined, we found 18 FAFLP profiles, compared with 12 macrorestriction profiles by pulsed-field gel electrophoresis. FAFLP readily distinguished genotypes for two clones of GAS serotype M77 which were responsible for outbreaks of invasive disease in a care-of-the-elderly system. It provided an automated analysis of the whole genome of bacterial isolates. It was reproducible, more discriminatory, and capable of higher throughput than other molecular typing methods. Given agreed conditions, FAFLP would be reproducible between laboratories for rapid characterization of outbreak strains.

Aged↗
PubMed1998

MR imaging of the normal and abnormal retrocalcaneal bursae.

OBJECTIVE: The aim of this study was to define the MR imaging criteria for normal and abnormal retrocalcaneal bursae. SUBJECTS AND METHODS: Fifty ankles in 25 asymptomatic volunteers and 30 ankles in patients with Achilles tendon disorders underwent MR imaging. Increased signal intensity consistent with fluid or synovium outlining the retrocalcaneal bursa was measured. RESULTS: Of 80 bursae, 77 (96%) had measurable fluid or synovial signal intensity revealed by MR imaging. Asymptomatic volunteers had average bursal dimensions of 1 mm in the anteroposterior dimension, 6 mm in the transverse dimension, and 3 mm in the craniocaudal dimension. Bursal dimensions greater than 1 mm, 11 mm, or 7 mm, respectively, were not seen in asymptomatic subjects but were seen in 16 (53%) of 30 ankles of patients with Achilles tendon disorders. CONCLUSION: On MR imaging, the asymptomatic retrocalcaneal bursa normally contains detectable high-signal-intensity fluid or synovium or both. A bursa larger than 1 mm anteroposteriorly, 11 mm transversely, or 7 mm craniocaudally is abnormal.

Achilles Tendon↗
PubMed1998

Profile of women undergoing reversal of sterilisation.

Two hundred twenty women who were subjected to reversal of female sterilisation over 7 years were analysed. It was found that death of the male child was the strongest reason for seeking a reversal. This was coupled with the parity of these subjects being two or less in 70% instances at the time of primary sterilisation surgery. Nearly 85.9% reversal were sought in the higher age groups clubbed together. This has an adverse bearing on success of reversal surgery as the fertility potential of a woman declines physiologically as age advances.

Adult↗
PubMed1997

Gluconeogenesis, glucose handling, and structural changes in livers of the adult offspring of rats partially deprived of protein during pregnancy and lactation.

Maternal protein restriction is a model of fetal programming of adult glucose intolerance. Perfused livers of 48-h- starved adult offspring of rat dams fed 8% protein diets during pregnancy and lactation produced more glucose from 6 mM lactate than did control livers from rats whose dams were fed 20% protein. In control livers, a mean of 24% of the glucose formed from lactate in the periportal region of the lobule was taken up by the most distal perivenous cells; this distal perivenous uptake was greatly diminished in maternal low protein (MLP) livers, accounting for a major fraction of the increased glucose output of MLP livers. In control livers, the distal perivenous cells contained 40% of the total glucokinase of the liver; this perivenous concentration of glucokinase was greatly reduced in MLP livers. Intralobular distribution of phosphenolpyruvate carboxykinase was unaltered, though overall increased activity could have contributed to the elevated glucose output. Hepatic lobular volume in MLP livers was twice that in control livers, indicating that MLP livers had half the normal number of lobules. Fetal programming of adult glucose metabolism may operate partly through structural alterations and changes in glucokinase expression in the immediate perivenous region.

Animals↗
PubMed1997

Residues within the polycationic region of cGMP phosphodiesterase gamma subunit crucial for the interaction with transducin alpha subunit. Identification by endogenous ADP-ribosylation and site-directed mutagenesis.

Interaction between the gamma subunit (Pgamma) of cGMP phosphodiesterase and the alpha subunit (Talpha) of transducin is a key step for the regulation of cGMP phosphodiesterase in retinal rod outer segments. Here we have utilized a combination of specific modification by an endogenous enzyme and site-directed mutagenesis of the Pgamma polycationic region to identify residues required for the interaction with Talpha. Pgamma, free or complexed with the alphabeta subunit (Palphabeta) of cGMP phosphodiesterase, was specifically radiolabeled by prewashed rod membranes in the presence of [adenylate-32P]NAD. Identification of ADP-ribose in the radiolabeled Pgamma and radiolabeling of arginine-replaced mutant forms of Pgamma indicate that both arginine 33 and arginine 36 are similarly ADP-ribosylated by endogenous ADP-ribosyltransferase, but only one arginine is modified at a time. Pgamma complexed with Talpha (both GTP- and GDP-bound forms) was not ADP-ribosylated; however, agmatine, which cannot interact with Talpha, was ADP-ribosylated in the presence of Talpha, suggesting that a Pgamma domain containing these arginines is masked by Talpha. A Pgamma mutant (R33,36K), as well as wild type Pgamma, inhibited both GTP hydrolysis of Talpha and GTP binding to Talpha. Moreover, GTP-bound Talpha activated Palphabeta that had been inhibited by R33,36K. However, another Pgamma mutant (R33,36L) could not inhibit these Talpha functions. In addition, GTP-bound Talpha could not activate Palphabeta inhibited by R33,36L. These results indicate that a Pgamma domain containing these arginines is required for its interaction with Talpha, but not with Palphabeta, and that positive charges in these arginines are crucial for the interaction.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1997

Two variants of quantitative reverse transcriptase PCR used to show differential expression of alpha-, beta- and gamma-fibrinogen genes in rat liver lobes.

Quantitative reverse transcriptase PCR (RT-PCR) is a sensitive method for the measurement of mRNA copy number. However, the methodology has gained a reputation for poor reproducibility, leading to concern over the validity of much of the data generated using this technique. We have developed two variants of quantitative competitive RT-PCR using a synthesized RNA as an internal standard to measure precisely the relative levels of alpha-, beta- and gamma-fibrinogen mRNAs in the four lobes of the rat liver. In the first of these variants we altered only the amount of total RNA in the RT-PCR reaction, keeping the amount of internal standard RNA and the number of PCR cycles constant. In the second variant only the number of PCR cycles was altered, and the amounts of total RNA and standard RNA were kept constant. Both variants of RT-PCR allowed calculation of the number of mRNA copies, which did not differ significantly between the two techniques. Of the two variants, the second gave better reproducibility, and the intra-assay coefficient of variation for this technique was 14% (n = 20). Using these two variants we have shown that there are different numbers of fibrinogen mRNAs in the four liver lobes for each of the three genes (alpha-fibrinogen F = 14.64, P = 0.0003; beta-fibrinogen F = 3.74, P = 0.04; gamma-fibrinogen F = 3.75, P = 0.04). In conclusion, by using two variants of quantitative competitive RT-PCR we have shown that this technique can be used to give reproducible results, and the low intra-assay coefficient of variation suggests that quantitative RT-PCR should be the technique of choice for accurate measurement of mRNA copy number.

Animals↗
PubMed1997

The effects of maternal protein deprivation on the fetal rat pancreas: major structural changes and their recuperation.

There is evidence that low birth weight and poor growth in early life cause a long-term predisposition to non-insulin-dependent diabetes. Morphological changes were assessed in fetal rat pancreas subjected to both pre- and post-natal maternal protein deprivation (LP). Further groups were subjected to purely prenatal maternal protein deprivation (preLP) and purely postnatal maternal protein deprivation (postLP), as well as a control group. The results show that the LP and postLP groups had fewer but larger islets than the control group, while the preLP group had more numerous, smaller islets. All three low protein groups had more irregularly shaped islets than the control group. There was a reduction in the amount of beta cells within each islet in all three protein-deprived groups. The LP and postLP groups showed a reduction in the percentage of islet tissue and beta cells per pancreas, but the percentage of islet tissue expressed per unit body weight was similar in all four groups. These results show that in maternal protein deprivation, homeostatic mechanisms ensure a constant amount of pancreatic endocrine tissue per unit of body weight. However, there remain major structural changes in the size, shape, and composition of the islets. These results support the theory that early development profoundly affects the structure of the pancreas and may play a role in the later development of adult diseases, such as non-insulin-dependent diabetes mellitus.

Animal Nutritional Physiological Phenomena↗
PubMed1997

Containment of a multiresistant Serratia marcescens outbreak.

A 3-year-old male from Bolivia who sustained a full-thickness 80 per cent TBSA burn complicated by smoke inhalation on the 28 March 1995 was admitted to our burn centre on 6 April 1995. On 11 April the patient's wounds were colonized with a Serratia marcescens sensitive only to ciprofloxacin and imipenem. Sputum cultures revealed the same phenotypic S. marcescens. Two patients who were admitted days later had the same phenotypic S. marcescens. Their TBSA burns ranged from 54 to 80 per cent. Both were injured in early April. Sputum and wound cultures were also positive for S. marcescens. Precautionary measures were instituted immediately. All potential reservoirs were cultured. Cultures were negative for S. marcescens. Patient therapy was maintained via strict isolation. The first patient died on 17 May. The two remaining patients survived and were discharged colonized with S. marcescens. However, the biotype of the initial S. marcescens was different from the latter two. Early recognition of a multiresistant S. marcescens resulted in negating the spread of this agent to other patients.

Adolescent↗
PubMed1997

Role of fetal and infant growth in programming metabolism in later life.

Fetal growth and development is dependent upon the nutritional, hormonal and metabolic environment provided by the mother. Any disturbance in this environment can modify early fetal development with possible long-term outcomes as demonstrated by extensive work on 'programming'. Growth restriction resulting from a deficit in tissue/organ cell number (as measured by tissue DNA content) is irrecoverable. However, when the cell size (or cell protein content) is reduced, the effects on growth may not be permanent. Recent epidemiological studies using archival records of anthropometric measurements related to early growth in humans have shown strong statistical associations between these indices of early development and diseases in later life. It has been hypothesised that the processes explaining these associations involve adaptive changes in fetal organ development in response to maternal and fetal malnutrition. These adaptations may permanently alter adult metabolism in a way which is beneficial to survival under continued conditions of malnutrition but detrimental when nutrition is abundant. This hypothesis is being tested in a rat model which involves studying the growth and metabolism in the offspring of rat dams fed a low-protein diet during pregnancy and/or lactation. Using this rat model, it has been demonstrated that there is: (i) Permanent growth retardation in offspring nursed by dams fed a low-protein diet. (ii) Permanent and selective changes in organ growth. Essential organs like the brain and lungs are relatively protected from reduction in growth at the expense of visceral organs such as the liver, pancreas, muscle and spleen. (iii) Programming of liver metabolism as reflected by permanent changes in activities of key hepatic enzymes of glycolysis and gluconeogenesis (glucokinase and phosphoenolpyruvate carboxykinase) in a direction which would potentially bias the liver towards a 'starved' setting. We have speculated that these changes could be a result of altered periportal and perivenous regions of the liver which may also affect other aspects of hepatic function. (iv) Deterioration in glucose tolerance with age. (v) An increase in the life span of offspring exposed to maternal protein restriction only during the lactation period, and a decrease in life span when exposed to maternal protein restriction only during gestation. These studies show that hepatic metabolism and even longevity can be programmed by events during early life.

Animals↗