PubMed Health⌕ Search

Biomedical subjects

S Prasad

Publications and source records attributed to S Prasad.

At least 37 records · Page 2Linked to original sources
PubMed2004

Mortality patterns in dairy animals under organized herd management conditions at Karnal, India.

Mortality patterns of two Zebu cattle breeds, Sahiwal and Tharparkar, and two crossbred strains, Karan Swiss and Karan Fries, maintained at the National Dairy Research Institute, Karnal were studied. Nine-year (1989--90 to 1997--98) data on mortality were analysed for year, season, age and cause effects on mortality rate. The overall mortality was 14.17%. The mortality in Sahiwal, Tharparkar, Karan Swiss and Karan Fries averaged 14.35%, 7.21%, 17.12% and 13.46%, respectively. The breed mortality rate did not vary significantly between years, seasons, age categories and causes of disease. However, the trends indicated appreciable difference in mortality rates. The mortality was highest in the year 1994--95 (19.53%) and lowest in 1991--92 (8.56%). There was very little variation in seasonal mortality rate and mortality rate averaged 4.53%, 4.81% and 4.84% in hot-dry (March-June), hot-humid (July-October) and cold (November-February) seasons, respectively. The mortality up to 2 months of age accounted for a major share (50-60% or higher) in different breed groups. Digestive problems followed by respiratory disorders together accounted for 70-80% of total deaths.

Age Distribution↗
PubMed2004

A combined extended and helical backbone for Boc-(Ala-Leu-Ac7c-)2-OMe.

The structure of the peptide Boc-Ala-Leu-Ac7c-Ala-Leu-Ac7c-OMe (Ac7c,1-aminocycloheptane-1-carboxylic acid) is described in crystals. The presence of two Ac7c residues was expected to stabilize a 3(10)-helical fold. Contrary to expectation the structural analysis revealed an unfolded amino terminus, with Ala(1) adopting an extended beta-conformation (Phi=-93 degrees, psi=112 degrees). Residues 2-5 form a 3(10)-helix, stabilized by three successive intramolecular hydrogen bonds. Notably, two NH groups Ala(1) and Ac7c(3) do not form any hydrogen bonds in the crystal. Peptide assembly appears to be dominated by packing of the cycloheptane rings that stack against one another within the molecule and also throughout the crystal in columns.

Amino Acids, Cyclic↗
PubMed2004

A genotype-phenotype correlation for GJB2 (connexin 26) deafness.

INTRODUCTION: Mutations in GJB2 are the most common cause of non-syndromic autosomal recessive hearing impairment, ranging from mild to profound. Mutation analysis of this gene is widely available as a genetic diagnostic test. OBJECTIVE: To assess a possible genotype-phenotype correlation for GJB2. DESIGN: Retrospective analysis of audiometric data from people with hearing impairment, segregating two GJB2 mutations. SUBJECTS: Two hundred and seventy seven unrelated patients with hearing impairment who were seen at the ENT departments of local and university hospitals from Italy, Belgium, Spain, and the United States, and who harboured bi-allelic GJB2 mutations. RESULTS: We found that 35delG homozygotes have significantly more hearing impairment, compared with 35delG/non-35delG compound heterozygotes. People with two non-35delG mutations have even less hearing impairment. We observed a similar gradient of hearing impairment when we categorised mutations as inactivating (that is, stop mutations or frame shifts) or non-inactivating (that is, missense mutations). We demonstrated that certain mutation combinations (including the combination of 35delG with the missense mutations L90P, V37I, or the splice-site mutation IVS1+1G>A, and the V37I/V37I genotype) are associated with significantly less hearing impairment compared with 35delG homozygous genotypes. CONCLUSIONS: This study is the first large systematic analysis indicating that the GJB2 genotype has a major impact on the degree of hearing impairment, and identifying mild genotypes. Furthermore, this study shows that it will be possible to refine this correlation and extend it to additional genotypes. These data will be useful in evaluating habilitation options for people with GJB2 related deafness.

Adolescent↗
PubMed2004

Waiting-list prioritization in the National Health Service.

The aim of this study was to find out whether there is a consensus of opinion among healthcare providers and different sections of the public on the relative prioritization of common otolaryngological conditions for outpatient consultations and inpatient treatment. ENT consultants, general practitioners, administrators, NHS employees, non-ENT patients and members of the general public were given common scenarios of otolaryngological conditions and asked to prioritize them in order of importance. All the groups gave top priority for patients with suspected cancer of the larynx (outpatients) and for surgical treatment of cancer. Children with hearing problems were more commonly ranked in the top three categories than children requiring treatment for sore throats. All groups assigned those requiring rhinoplasty, treatment for snoring or hearing aids to the last three ranks. This study shows that there is a remarkable uniformity of opinion in determining clinical priorities which is similar to the traditional policies practised by UK ENT consultants.

Adult↗
PubMed2004

Acute aortic dissection--De Bakey Type I and Stanford A.

We report a rare case of aortic dissection which fits into De Bakey Type I and Stanford A, presented with severe tearing chest pain, paraplegia, stupor, hypotension, and syncope. Echocardiography showed dissection involving aortic root. MRI showed aortic dissection involving ascending, arch and descending aorta. Patient was managed conservatively and he died within 12 hours after the admission.

Aged↗
PubMed2003

Reversal of cadmium induced oxidative stress by chelating agent, antioxidant or their combination in rat.

The influence of an antioxidant agent such as N-acetyl cysteine (NAC) or mannitol on the cadmium chelating ability of monoisoamyl 2,3-dimercaptosuccinate (MiADMS) was investigated in cadmium pre-exposed rats. This ester of 2,3-dimercaptosuccinic acid (DMSA), an accepted drug for lead poisoning, being lipophilic in nature was expected to be an efficient cadmium chelator. The treatment of cadmium intoxicated animals with MiADMS reversed cadmium induced increase in blood catalase, superoxide dismutase (SOD) and malondialdehyde (MDA), liver MDA and brain SOD and MDA levels but not the decrease in blood, liver brain reduced glutathione (GSH) and increase in oxidized glutathione (GSSG) levels, consistent with the lowering of tissue cadmium burden. The administration of NAC or mannitol reversed the cadmium induced alterations in blood and liver GSH, GSSG, blood catalase, SOD, MDA, liver SOD, MDA and brain MDA levels without lowering blood and tissue cadmium contents. However, treatments with the combination of MiADMS and NAC or MiADMS and mannitol reversed these alterations as well as reduced blood and tissue cadmium concentrations. The combined treatment with MiADMS and mannitol was better than that with MiADMS and NAC, and was significantly more effective in normalizing blood, liver GSH, GSSG, brain GSSG, and their GSH/GSSG ratios than that by either of them alone. The combined treatments also improved liver and brain endogenous zinc levels, which were decreased due to cadmium toxicity. The results suggest that the administration of an antioxidant during chelation of cadmium may provide beneficial effects by reducing oxidative stress without its cadmium removing ability.

Acetylcysteine↗
PubMed2003

Effect of lycopene on pre-eclampsia and intra-uterine growth retardation in primigravidas.

OBJECTIVES: To observe the effect of the antioxidant lycopene on the occurrence of pre-eclampsia and intrauterine growth retardation in primigravida women. METHODS: A total of 251 primigravida women were enrolled in this prospective, randomized controlled study in the second trimester. A total of 116 women were given oral lycopene (Group I) in a dose of 2 mg twice daily while 135 women were given a placebo (Group II) in the same dose until delivery. The criteria for recruitment included gestational age of 16-20 weeks, singleton pregnancy, absence of any medical complication and willingness on the part of the women to participate in the study. The women were followed-up until delivery for development of pre-eclampsia, mode of delivery and fetal outcome. RESULTS: The two groups were comparable in their maternal characteristics. Pre-eclampsia developed in significantly less women in the lycopene group than in the placebo group (8.6% vs. 17.7%, P=0.043 by chi-square test). Mean diastolic blood pressure was significantly higher in the placebo group (92.2+/-5.98 mmHg vs. 86.7+/-3.80 mmHg, P=0.012). Mean fetal weight was significantly higher in the lycopene group (2751.17+/-315.76 g vs. 2657+/-444.30 g, P=0.049). The incidence of intrauterine growth retardation was significantly lower in the lycopene group than in the placebo group (12% vs. 23.7%, P=0.033). CONCLUSIONS: The results of the present study suggest that the antioxidant lycopene reduces the development of pre-eclampsia and intrauterine growth retardation in primigravida women.

Adult↗
PubMed2003

Is magnetic resonance angiography useful in renovascular disease?

BACKGROUND: Magnetic resonance angiography (MRA) of renal vessels correlates well with conventional angiography (CA) and enables non-invasive assessment of renal vessels without nephrotoxic contrast. AIMS: We aimed to identify the referral source and nature of the patient group undergoing renal MRA, and the impact of this test on their management. METHODS: All renal MRA scans performed at the Royal Adelaide Hospital from 1 November 1997 to 31 December 2000 were reviewed (n = 121). Clinical data were obtained by case-note review or from treating physicians. MRA scans were with gadolinium enhancement, using a Siemens Vision 1.5 Tesla machine (Siemens, New York), with Visual Basic 33 software and 3D reconstruction. RESULTS: Nephrologists ordered the majority of renal MRA studies (64.5%). Indications for MRA included: (i). hypertension (91.3%), (ii). abnormal renal function (78.3%), (iii). other imaging suggesting renovascular disease (64.3%) and (iv) renal impairment with angiotensin-converting enzyme inhibition (18.3%). Eighty-seven MRA studies revealed renovascular abnormalities ('positive'). Over 50% of patients had three or more risk factors associated with vascular disease, with MRA positive in 76%. Localized renal artery stenosis was identified in 65 cases. In 40 of these, CA and further intervention was not undertaken, mainly due to presence of features of irreversible renal damage, low-grade stenosis or stable clinical parameters. CA was performed in 25 patients, all of whom had moderate- to high-grade (>60%)-stenosis on MRA. Revascularization was attempted in 21 of the 25 patients, with technical success in 17. In 22 patients, MRA identified non-localized abnormalities, most commonly diffuse arterial disease. None went on to angiography. CONCLUSIONS: Selective use of renal MRA in high-risk patients (identified by vascular risk factors or with standard renal imaging) can assist in avoidance of invasive, potentially nephrotoxic conventional angiography in up to 80% of cases. Those with lesions warranting treatment can then be selected for further intervention.

Adult↗
PubMed2003

Organized vitreous hemorrhage masquerading as an optic disc melanocytoma.

PURPOSE: To present a case of organized vitreous hemorrhage masquerading an optic disc melanocytoma. DISCUSSION: Optic nerve head melanocytoma is a benign slightly pigmented lesion arising from the edge of the disc presenting with a filed defect. Pigmented nature of the lesion in question due to presence of haemosidrin laden macrophages led a diagnostic dilemma. Trans vitreal biopsy confirmed the diagnosis. CONCLUSIONS: Althought classical in presentation organized blood clots can masquerade a number of lesions including a melanocytoma as in the present scenario.

Adult↗
PubMed2002

Reversal of lead-induced oxidative stress by chelating agent, antioxidant, or their combination in the rat.

The influence of N-acetyl cysteine (NAC), an antioxidant, on the therapeutic efficacy of meso-2,3-dimercaptosuccinic acid (DMSA), a hydrophilic, and its ester, monoisoamyl 2,3-dimercaptosuccinate (MiADMS), a lipophilic, both soft tissue lead mobilizers, was investigated in lead-preexposed rats. The subsequent treatment of lead-exposed animals with DMSA, MiADMS, or NAC reversed the lead-induced alterations in blood delta-aminolevulinic acid dehydratase, catalase, malondialdehyde (MDA), reduced glutathione, oxidized glutathione, and brain MDA levels. The combined treatment with DMSA and NAC was more effective than that with MiADMS and NAC in enhancing the restoration of all these parameters indicative of lead-induced oxidative stress. These reversals were consistent with the lead-removing ability of DMSA and MiADMS but not that of NAC. As the reversal of these parameters by NAC was independent of its lead-mobilizing capability, this ought to be mainly due to its strong antioxidant property. The increase in blood and brain zinc levels upon lead exposure appears to be the result of the redistribution of endogenous zinc due to lead. Subsequent treatment with DMSA, MiADMS, NAC, or their combination decreased the brain zinc as its excretable complexes with a transient increase in blood zinc level. The ideal treatment of lead poisoning seems to be a combination of a lead chelator and an antioxidant.

Acetylcysteine↗
PubMed2002

Live donor renal transplantation in Australia 1964-1999: an evolving practice.

BACKGROUND: Australia has a low cadaver organ donor (CD) rate by international standards, leading to the increasing use of live donor (LD) renal grafts. AIMS: To review the Australian experience with LD transplants from 1964 to 1999. METHODS: Data were obtained from the Australian and New Zealand Dialysis and Transplant Registry. Survival was assessed by the Kaplan-Meier method. RESULTS: A total of 1584 LD and 10 252 CD transplants was performed between 1964 and 1999. While the CD rate dropped over the last decade, the LD rate increased, maintaining the overall transplantation rate. Only 3.6% of grafts before 1980 were LD, increasing to 28.4% during 1995-1999. Patient and graft survival of LD grafts was superior to CD grafts. Most LD grafts were from live related donors (LRD), most commonly parents or siblings. The number of transplants from live unrelated donors (LURD) has risen (1980-1989, n = 6; 1990-1999, n = 143), primarily due to more spousal donation, with no difference in survival between LRD and LURD groups. Grafts from older donors (> 50 years of age) increased, with no graft survival difference between donors < 50 years and donors > 50 years. LD transplants performed prior to commencement of dialysis increased, with survival similar to grafts performed after dialysis. CONCLUSION: The pattern of renal transplantation in Australia has changed, with increasing numbers of LD transplants, growing use of unrelated and older donors, and more transplants before dialysis commences. Long-term patient and graft survival advantages have been maintained, supporting the growing use of live donors to expand the donor pool.

Adult↗
PubMed2001

Genomic structures of SCN2A and SCN3A - candidate genes for deafness at the DFNA16 locus.

DFNA16 is a form of autosomal dominant non-syndromic hearing loss (ADNSHL) characterized by fluctuating progressive hearing impairment. Earlier, we mapped the deafness-causing gene to chromosome 2q23-24.3. In this paper, we describe fine mapping results using additional markers tightly linked to the DFNA16 candidate region. Critical recombinants at markers D2S354 and D2S124 define a 3.5-cM interval that contains the DFNA16 gene. Positional candidate genes include two members of the voltage-gated sodium channel family, the type 2 alpha subunit (SCN2A) and the type 3 alpha subunit (SCN3A). After showing that SCN2A is expressed in human fetal cochlea, we determined its genomic structure to facilitate mutation screening in our DFNA16 kindred. We also determined the genomic structure of SCN3A. These two genes are oriented head-to-head, with their 5' ends separated by approximately 40 kb; their homology is 82% at the nucleotide level, and 85% for identities and 90% for positives at the amino acid level. They share similar genomic structures and have alternative splice isoforms that are developmentally regulated and highly conserved between species. Although no DFNA16-causing mutations were found in either gene, haplotype analysis with polymorphic markers in SCN2A introns further narrowed the candidate gene interval to the region flanked by D2S354 and STS SHGC-82894.

Alternative Splicing↗
PubMed2001

Mutations in the transcriptional activator EYA4 cause late-onset deafness at the DFNA10 locus.

We identified Eyes absent 4 (EYA4), a member of the vertebrate Eya family of transcriptional activators, as the causative gene of postlingual, progressive, autosomal dominant hearing loss at the DFNA10 locus. In two unrelated families from Belgium and the USA segregating for deafness at this locus, we found different mutations in EYA4, both of which create premature stop codons. Although EYA proteins interact with members of the SIX and DACH protein families in a conserved network that regulates early embryonic development, this finding shows that EYA4 is also important post-developmentally for continued function of the mature organ of Corti.

Age of Onset↗