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Biomedical subjects

S Prasad

Publications and source records attributed to S Prasad.

At least 19 recordsLinked to original sources
PubMed2026

Craniotomy versus Endoscopic Membranectomy in the Treatment of Non-Homogeneous Chronic Subdural Hematoma: A Pilot Randomized Parallel-Group Active-Controlled Trial (EMiT CSDH 2).

BACKGROUND: Chronic subdural hematoma (CSDH) is a prevalent neurosurgical condition with persistent challenges related to recurrence. Endoscopic membranectomy (EM) has shown promising results in managing symptomatic non-homogenous (SNH)-CSDH, but comparative evidence against craniotomy with membranectomy (CM) is lacking. OBJECTIVES: To compare the safety and efficacy of EM versus CM in managing SNH-CSDH. MATERIALS AND METHODS: A pilot randomized parallel-group active-controlled open- labeled superiority trial from September 2023 to November 2024 at Government Kilpauk Medical College, Chennai, India. Sixty patients with SNH-CSDH were randomized into EM and CM groups. Recurrence was the primary outcome. Secondary outcomes included operative time, complications, radiological indices, pain, hospital stay, and functional recovery. All patients were followed for six months. RESULTS: No recurrence was observed in either group at six months. Two CM patients required reoperation on postoperative day one ( P = 0.15). EM was associated with shorter operative time ( P = 0.02), lower incidence of post-operative subdural residual fluid ( P = 0.015), better early hematoma reduction/subdural space reduction index ( P = 0.008), midline shift/symmetry improvement index ( P = 0.001), and lesser surgical site swelling ( P < 0.001). All patients were ambulant and had a Glasgow coma scale (GCS) 15 at discharge and at six months (including reoperated patients). Pain scores and functional recovery were comparable. EM patients had shorter hospital stays ( P = 0.004) and no significant complications. CONCLUSION: EM demonstrated favorable early radiological outcomes, fewer complications, and comparable functional recovery and recurrence versus CM in SNH-CSDH. Independent reproduction and larger multicentric trials are needed for validity and generalizability.

Humans↗
PubMed2007

Bioconversion of butyronitrile to butyramide using whole cells of Rhodococcus rhodochrous PA-34.

Butyramide is an important chemical commodity, which is used for the synthesis of hydroxamic acids and electrorheological fluids and for the preparation of beta-amodoorganotin compounds. The nitrile hydratase (Nhase) of Rhodococcus rhodochrous PA-34 catalyzed the conversion of butyronitrile to butyramide. The maximum Nhase activity [18 U/mg dry cell weight (dcw)] of whole cells of R. rhodochrous PA-34 was observed at pH 7.0 with 10% (v/v) butyronitrile and 1 mg cells (dcw)/ml reaction mixture at 10 degrees C. The cells of R. rhodochrous PA-34 retained almost 50% activity when incubated for 1 h in the presence of 85% (v/v) butyronitrile. A yield of 597 g of butyramide (6.8 M) was obtained using 60% (v/v) butyronitrile, 1 g cells (dry weight) in a 1-l batch reaction at 10 degrees C for 6 h.

Amides↗
PubMed2007

Psychological implications of ICD implantation in a New Zealand population.

AIMS: Previous studies have raised concerns about high levels of anxiety and depression in implanted cardioverter-defibrillator patients, and suggested that adverse psychological outcomes have been related to delivered therapy, age, and gender. This study aimed to assess the prevalence of anxiety and depression and to analyse quality-of-life in a New Zealand patient group. METHODS AND RESULTS: We questioned 46 ICD and 49 pacemaker patients regarding device and treatment satisfaction, depression, anxiety (Hospital Anxiety and Depression Scale), and quality-of-life (SF 36). The prevalence of clinical depression and anxiety in the ICD group was 7 and 13%, respectively, and did not differ from the pacemaker group. ICD patients mean anxiety and depression scores did not differ from the pacemaker group, although more ICD patients had subclinical levels of anxiety. Quality-of-life scores were normal for all ICD patients with respect to both mental and physical component scores, and not different from the pacemaker group. Anxiety, depression, and quality-of-life scores were unrelated to time from implantation, delivered therapy, age, or gender. Overall, 93% of the ICD patients thought their device was worthwhile. CONCLUSION: We found a lower than expected level of anxiety and depression in ICD patients, and suggest that this may be due in part to the small team approach adopted locally in the follow-up of this patient group.

Adult↗
PubMed2006

Spectral editing in solid-state MAS NMR of quadrupolar nuclei using selective satellite inversion.

A sensitivity enhancement method based on selective adiabatic inversion of a satellite transition has been employed in a (pi/2)CT-(pi)ST1-(pi/2)CT spectral editing sequence to both enhance and resolve multisite NMR spectra of quadrupolar nuclei. In addition to a total enhancement of 2.5 times for spin 3/2 nuclei, enhancements up to 2.0 times is reported for the edited sites in a mixture of rubidium salts.

Algorithms↗
PubMed2006

Fragile x mental retardation (Fmr-1) gene expression is down regulated in brain of mice during aging.

Fragile x syndrome (FXS) is the most common form of inherited mental retardation disease. This is caused due to expansion of CGG triplet in 5'-untranslated region of fragile x mental retardation 1 (FMR-1) gene. In most of the cases, abnormally large size of the CGG repeat (>200) undergoes hypermethylation, which in turn silences the FMR-1 gene causing thereby complete lack of its protein product called fragile x mental retardation protein (FMRP). Lack of FMRP due to gene silencing or production of faulty protein due to point mutation in KH2 domain of FMRP alters the translational process in neurons and leads to expression of mental retardation phenotype on the patients. The FMRP is expressed ubiquitously in all tissues; however, it is predominantly expressed in neurons and testis. It possesses heterogeneity and is found in many isoforms due to alternative splicing of the FMR-1 transcript. Based on our data from the Western-, slot-, Northern blotting and immunohistochemical studies, we report here the down regulation of Fmr-1 gene and FMRP in mice brain in age-dependent manner. The present finding is important in respect to FMRP-dependent various brain functions i.e., learning, memory, cognition etc. that decrease with advancing age.

Aging↗
PubMed2006

Endocapsular iris reconstruction implants for acquired iris defects: a clinical study.

PURPOSE: To report the clinical efficacy, safety, and long-term follow-up data on the use of endocapsular iris reconstruction implants (IRIs) during cataract surgery in patients with acquired iris defects. METHODS: Single centre, retrospective, noncomparative, interventional case series. Five eyes of four patients with acquired iris defects and visually significant cataracts underwent clear cornea phacoemulsification and intraocular lens (IOL) implantation combined with insertion of endocapsular IRI. Data on the best-corrected visual acuity (BCVA), degree of preoperative and postoperative glare, photophobia, surgical complications, and long-term implant stability were analysed. RESULTS: In all patients, IRI were successfully placed within the capsular bag during cataract surgery. There were no intraoperative or postoperative complications. Mean follow-up period was 29 months (range, 16-42). BCVA, subjective glare, and photophobia improved in all five eyes. Desired anatomic results were achieved in all of them. CONCLUSIONS: In patients with acquired iris defects, implantation of endocapsular IRI during cataract surgery appears to be a safe and effective procedure. At a mean time gate of 29 months, both IOLs and IRI appeared to remain stable within the capsular bag.

Adult↗
PubMed2006

Abnormal glucose metabolism and features of the metabolic syndrome are common in patients presenting for elective cardiac catheterization.

BACKGROUND: Abnormalities of glucose metabolism and the metabolic syndrome, including excess bodyweight, are potentially modifiable risk factors for cardiac morbidity and mortality. This study aimed to determine the prevalence of these in a group of patients presenting for elective cardiac catheterization or percutaneous intervention. METHODS: Data were prospectively collected on 297 consecutive patients presenting for elective cardiac catheterization or percutaneous intervention at a single tertiary referral centre. Demographic data, risk factors, medications and coronary angiogram results were recorded. Fasting lipids, fasting glucose, HbA1c levels were measured and if necessary an oral glucose tolerance test was carried out. Logistic regression and contingency table analysis examined associations of these with ethnicity. RESULTS: Impaired glucose metabolism (diabetes, impaired glucose tolerance or impaired fasting glucose) was present in 46.1% with our screening programme detecting previously unknown impaired glucose metabolism in 22.9%. Impaired glucose metabolism was strongly associated with non-European ethnicity (P < 0.0001). The metabolic syndrome was present in 49.2%. When defined by ethnic specific cut-offs, overweight or obesity was present in >80% of patients in all ethnic groups. CONCLUSION: There is a very high prevalence of impaired glucose metabolism and the metabolic syndrome in patients presenting for cardiac catheterization. Impaired glucose metabolism is particularly prevalent in the Polynesian and the Indian and the Sri Lankan ethnic groups. Screening of patients undergoing elective cardiac catheterization identifies a significant number of patients with undiagnosed impaired glucose metabolism and should be carried out routinely.

Aged↗
PubMed2006

Constitutive acetonitrile hydrolysing activity of Nocardia globerula NHB-2: Optimization of production and reaction conditions.

Nocardia globerula NHB-2 exhibited an intracellular acetonitrile hydrolysing activity (AHA) when cultivated in nutrient broth supplemented with glucose (10.0 g/l) and yeast extract (1.0 g/l), at pH 8.0, 30 degrees C for 21 hr. Maximum AHA was recorded in the culture containing 0.1 M of sodium phosphate buffer, (pH 8.8) at 45 degrees C for 15 min with 600 micromol of acetonitrile and resting cells of N. globerula NHB-2 equivalent to 1.0 ml culture broth. This activity was stable up to 40 degrees C and was completely inactivated at or above 60 degrees C. About five-fold increase in AHA was observed after optimization of culture and reaction conditions. Under the optimized conditions, this organism hydrolyzed various nitriles and amides such as propionitrile, benzonitrile. acetamide, and acrylamide to corresponding acids. This nitrile/amide hydrolysing activity of N. globerula NHB-2 has potential applications in enzymatic synthesis of organic acids and bioremediation of nitriles and amides contaminated soil and water system.

Acetonitriles↗
PubMed2005

Mitigating nitrous oxide and methane emissions from soil in rice-wheat system of the Indo-Gangetic plain with nitrification and urease inhibitors.

Mitigation of methane (CH4) and nitrous oxide (N2O) emissions from soil is important to reduce the global warming. Efficacy of five nitrification inhibitors, i.e. neem (Azadirachta melia) cake, thiosulphate, coated calcium carbide, neem oil coated urea and dicyandiamide (DCD) and one urease inhibitor, hydroquinone, in mitigating N2O and CH4 emissions from fertilized soil was tested in rice-wheat system in the Indo-Gangetic plains. The closed chamber technique was used for the collection of gas samples, which were analyzed using gas chromatography. Reduction in N2O emission on the application of nitrification/urease inhibitors along with urea ranged from 5% with hydroquinone to 31% with thiosulphate in rice and 7% with hydroquinone to 29% with DCD in wheat crop. The inhibitors also influenced the emission of CH4. While application of neem coated urea, coated calcium carbide, neem oil and DCD reduced the emission of CH4; hydroquinone and thiosulphate increased the emission when compared to urea alone. However, the global warming potential was lower with the inhibitors (except hydroquinone) as compared to urea alone, suggesting that these substances could be used for mitigating greenhouse gas emission from the rice-wheat systems.

Acetylene↗
PubMed2005

Skewed T-cell receptor BV14 and BV16 expression and shared CDR3 sequence and common sequence motifs in synovial T cells of rheumatoid arthritis.

T-lymphocytes play an important role in rheumatoid arthritis (RA). In this study, we evaluated the hypothesis that common T-cell receptor (TCR) structural features may exist among infiltrating T cells of different RA patients, if the TCR repertoire is shaped by interaction with common self or microbial antigens in the context of susceptible HLA genes in RA. Synovial lesion tissue (ST), synovial fluid (SF) and blood specimens from RA patients and controls were analyzed for TCR V gene repertoire by real-time PCR. There was highly skewed BV14 and BV16 usage in synovial T cells of RA as opposed to those of controls, which was accompanied with a trend for correlation between skewed BV16 and DRB1(*)0405. Immunoscope analysis of the V-D-J region of ST-derived T cells demonstrated oligoclonal and polyclonal expansion of BV14(+) and BV16(+) T cells. Detailed characterization using specific BV and BJ primers further revealed common clonotypes combining the same BV14/BV16, BJ and CDR3 length. DNA cloning and sequence analysis of the clonotypes confirmed identical CDR3 sequences and common CDR3 sequence motifs among different RA patients. The findings are important in the understanding of BV gene skewing and CDR3 structural characteristics among synovial infiltrating T cells of RA.

Arthritis, Rheumatoid↗
PubMed2005

Furanoid sugar amino acids as dipeptide mimics in design of analogs of vasoactive intestinal peptide receptor binding inhibitor.

In this study we describe the development of peptidomimetic analogs of the potent vasoactive intestinal peptide receptor binding inhibitor, Leu(1) -Met(2) -Tyr(3) -Pro(4) -Thr(5) -Tyr(6) -Leu(7) -Lys(8) -OH 1, by incorporating furanoid sugar amino acids (SAAs) 2-4 into the molecule. The furanoid SAAs 2-4 were used as dipeptide isosteres to replace Tyr(3) -Pro(4) or Pro(4) -Thr(5) in sequence 1. The resulting analogs 5-9 were tested for their anti-cancer activities in vitro, following the standard MTT assay on a panel of human cancer cell lines. One of the potent analogs, 6a was tested in vivo for tumor regression on primary colon tumor xenografted nude mice. Our experimental results suggest that many of these analogs show either retention or enhancement of biological activity.

Adenocarcinoma↗
PubMed2005

Survey of the Royal Australasian College of Physicians examination candidates: preparation and impact on lifestyle.

Candidates currently view the Royal Australasian College of Physicians' written examination as a major undertaking, knowing that approximately one-third fail on their first attempt. We anonymously surveyed New Zealand registrars who sat the written examination in 2004. We found that the majority of candidates spend long hours preparing over a several months, and that the examination had a detrimental impact on their personal lives. The results of this survey have important implications in the context of efforts to reduce the stress of doctors, and should lead to a change in either the examination itself or an increase in support provided to registrars preparing for it.

Adult↗
PubMed2005

A new paradigm for developing drugs in children: atomoxetine as a model.

When prescribing drugs for children, it is fundamental to acknowledge that they are distinct from adults with a different physiology and metabolism. They are also still maturing. The development of drugs with a primarily paediatric indication thus requires the trialling of these drugs in a paediatric population to assess safety, tolerability, and efficacy as appropriately as possible. When designing and running a paediatric clinical trial, a number of complexities must be addressed to ensure a successful study, including practical considerations, ethical issues, and tailoring communication appropriately to study participants and parents. The drug development process for atomoxetine, a novel, non-stimulant treatment for attention deficit/hyperactivity disorder (ADHD), encompassed a preclinical programme, initial trials in healthy adults, and a proof of concept trial in adults with ADHD. Open label and placebo controlled studies in paediatric patients followed, thus establishing the drug's safety and efficacy in children with ADHD. Further trials have addressed, and continue to address, wider aspects of the atomoxetine response in a paediatric setting.

Age Factors↗
PubMed2005

Short-term zinc deficiency in diet induces increased oxidative stress in testes and epididymis of rats.

In order to determine the effects of Zinc deficient diet on oxidative stress in testis and epididymis, various parameters viz: total proteins, lipid peroxidation, hydroperoxides, antioxidant capacity and enzymatic activities are evaluated in rats fed on zinc deficient diet for 2, 4 and 6 weeks. Total proteins, water and lipid solouble antioxidant capacity decreased while lipid peroxidation (TBARS) and hydroperoxides concentration increased in testes, caput and cauda epididymis except in 2ZD (testes) where hydroperoxides revealed a significant decrease. GSH decreased in testes and caput and cauda epididymis. GPx and gamma-GT activities increased in testes and caput and cauda epididymis of zinc deficient rats. Further, GST increased in testes but exhibited decreases after 2 and 4 weeks and an increase after 6 weeks in caput and cauda epididymis of zinc deficient rats. GR activities decreased in testes but it increased in caput and cauda epididymis of zinc deficient rats. Thus, zinc deprivation results in increased sensitivity to oxidative stress. All these may have been as a consequence of increased ROS generation and/or decreased zinc dependent antioxidant processes.

Animals↗
PubMed2004

Association analysis of NOTCH 4 polymorphisms with schizophrenia among two independent family based samples.

The present study investigated polymorphisms of the NOTCH 4 gene in two independent samples from India and USA, consisting of patients with schizophrenia and their parents (n = 182, and n = 148 'trios,' respectively). Five DNA markers, namely (GAAG)(n), (TAA)(n), SNP1, SNP2, and (CTG)(n) were evaluated. Transmission distortion, consistent with a modest association was detected among both samples. Additional association studies at this locus are warranted.

Alleles↗