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Biomedical subjects

S N Singh

Publications and source records attributed to S N Singh.

At least 19 recordsLinked to original sources
PubMed2006

Use of RAPD fingerprinting for delineating populations of hilsa shad Tenualosa ilisha (Hamilton, 1822).

RAPD was used to delineate the hilsa populations sampled from the Ganga, Yamuna, Hooghly, and Narmada Rivers at six different locations. Six degenerate primers were used to generate the fragment patterns from the samples collected. All primers were highly polymorphic and generated high numbers of amplification products. Nei's genetic distances were calculated between locations. The overall average genetic distance among all the six locations was 0.295. The Fst value within the Ganga was 0.469 and within the Hooghly it was 0.546. The overall Fst value for the six populations analyzed was 0.590. The UPGMA dendrogram clustered the hilsa into two distinct clusters: Ganga and Yamuna populations and the Hooghly and Narmada populations.

Animals↗
PubMed2006

Biochemical and ultrastructural changes in plant foliage exposed to auto-pollution.

Auto-pollution is the by-product of our mechanized mobility, which adversely affects both plant and human life. However, plants growing in the urban locations provide a great respite to us from the brunt of auto-pollution by absorbing the pollutants at their foliar surface. Foliar surface configuration and biochemical changes in two selected plant species, namely Ficus religiosa L. and Thevetia nerifolia L., growing at IT crossing (highly polluted sites), Picup bhawan crossing (moderately polluted site) and Kukrail Forest Picnic Spot (Low polluted site) were investigated. It was observed that auto-exhaust pollution showed marked alterations in photosynthetic pigments, protein and cysteine contents and also in leaf area and foliar surface architecture of plants growing at HP site as compared to LP site. The changes in the foliar configuration reveal that these plants can be used as biomarkers of auto-pollution.

Air Pollution↗
PubMed2005

Studies on diaminoglyoxime (DAG): thermolysis and evaluation as ballistic modifier in double base propellant.

This paper reports thermolysis of diaminoglyoxime (DAG) and its evaluation as a ballistic modifier in double base propellant formulations. Differential scanning calorimetry (DSC) and simultaneous thermal analysis (DTA-thermogravimetric (TG)) revealed that DAG decomposes in two stages. Kinetics of initial stage of thermal decomposition of DAG evaluated from TG data gave activation energy (E(a)) of 153 kJmol(-1). The high-temperature Fourier transform Infrared (FTIR) spectra of DAG suggested preferential cleavage of NO and CNH2 during decomposition. Mass spectral data also suggest possibility of similar process. The hyphenated TG-FTIR data also revealed the evolution of gases containing species, such as CN, NH, OH and oxides of nitrogen during thermal decomposition. Evaluation of DAG as a ballistic modifier in RDX incorporated double base propellant formulations indicated that it brings down the pressure index to 0.17 compared to 0.79 for a control composition in the pressure range 6.9-8.8 MPa when used in combination with basic lead salycilate (BLS). The study suggests that combination of DAG and BLS need to be optimized to achieve more remarkable effects than BLS alone. It was observed that DAG does not have adverse effect on vulnerability and chemical stability of the propellant formulation.

Aerosol Propellants↗
PubMed2005

Comparative study of complex spina bifida and split cord malformation.

OBJECTIVE: To see the difference in clinical profiles, radiological findings and surgical outcome of the group 1 split cord malformation and meningomyelocele (SCM with MMC) from group 2 (SCM without MMC). METHODS: 46 patients of SCM were selected from a total of 138 cases of spinal dysraphism. They were divided into two groups, based on presence or absence of MMC. Group I (SCM with MMC) n =19 patients and Group II (SCM without MMC) n=27 patients. A detail clinical evaluation and MR screening of whole spine of all cases was performed. All patients underwent surgical detethering of cord. After an average follow-up of 1.7 years, the operative results were clinically assessed and statistical significance was calculated. RESULTS: Male to female ratio was 1:09. Mean age of presentation was 3.6 years. Cutaneous markers like tuft of hair, cutaneous haemangioma, etc, had a higher incidence in group II in comparison to group I (50% vs 10.5%). The incidence of motor deficits was significant in group I in comparison to group II (63% vs 40%). The incidences of sensory loss, trophic ulcers, sphincteric dysfunction and muscle atrophy were relatively more common in group I patients, while neuro-orthopedic deformities such as congenital telepes equinovarus (CTEV), scoliosis and limb shortening were more frequent (67%) in group II children as compared to group I (53%). Type I SCM has higher incidence in group I children. Low lying conus were found in 47% patient of group I, while in group II it was noticed in 69%. The associated cranial anomalies like hydrocephalus, ACM and syrinx, were slightly higher in group I patients. At surgery, dysgenetic nerve roots, neural placode, arachnoid bands and atrophic cord were seen mainly in group I. Postoperative complications like, CSF leak, pseudomeningocele and meningitis were more commonly encountered in group I patients. The patients of group II showed better operative outcome compared to group I cases. CONCLUSION: Incidence of SCM with MMC amount to 41% of total SCM cases. Progressive neurological deficit was higher in this group (SCM with MMC) in comparison to the group harboring SCM without MMC. In view of a significant association of SCM in MMC cases, associated with other craniospinal anomalies, a thorough screening of neuraxis (by MRI) is recommended to treat all treatable anomalies simultaneously for desired outcome.

Adolescent↗
PubMed2005

The role of physical activity in the prevention of stroke.

Although large-scale epidemiologic studies, as well as interventional trials have provided strong evidence of a consistent and robust association between physical activity and cardiovascular disease, the effect of exercise on the burden of stroke is not well understood and appreciated. This review has a purpose to summarize the literature on the effect of physical activity on stroke morbidity and mortality, and to provide current scientific evidences.

Exercise↗
PubMed2003

Hyperostotic paraganglioma of occipitotemporal bone.

A 25-year-old male presented with off-and-on vertigo of 10-year duration. He had left-sided cerebellar signs, left vocal cord paresis, and minimal left-sided hearing impairment. Computed tomography of the head revealed significant hyperostosis of squamous occipital, mastoid, and petrous temporal bone with no adjacent soft tissue mass. On excision, it turned out to be paraganglioma. Paraganglioma as a pure bony mass is not reported in the literature. The site of origin of such a tumor could not be ascertained, even on generous screening. The tumor remained nonsecretory on clinical and biochemical investigations.

Adult↗
PubMed2003

Investigating options for attenuating methane emission from Indian rice fields.

The development of methods and strategies to reduce the emission of methane from paddy fields is a central component of ongoing efforts to protect the Earth's atmosphere and to avert a possible climate change. It appears from this investigation that there can be more than one strategy to contain methane emission from paddy fields, which are thought to be a major source of methane emission in tropical Asia. Promising among the mitigating options may be water management, organic amendments, fertilizer application and selection of rice cultivars. It is always better to adopt multi-pronged strategies to contain CH4 efflux from rice wetlands. Use of fermented manures with low C/N ratio, application of sulfate-containing chemical fertilizers, selection of low CH4 emitting rice cultivars, and implementation of one or two short aeration periods before the heading stage can be effective options to minimize CH4 emission from paddy fields. Among these strategies, water management, which appears to be the best cost-effective and eco-friendly way for methane mitigation, is only possible when excess water is available for reflooding after short soil drying at the right timing and stage. However, in tropical Asia, rice fields are naturally flooded during the monsoonal rainy season and fully controlled drainage is often impossible. In such situation, water deficits during the vegetative and reproductive stage may drastically affect the rice yields. Thus, care must be taken to mitigate methane emission without affecting rice yields.

Agriculture↗
PubMed2003

Spinal dysraphism: trends in northern India.

OBJECTIVE: To evaluate the clinical profiles, image findings and surgical outcome of 155 cases of spinal dysraphism. METHODS: 155 patients were studied prospectively (143) or retrospectively (12). The male to female ratio was 1.5:1. Mean age at presentation was 5.7 years. Out of 155 cases of spinal dysraphism, 119 had open spina bifida [meningomyelocele (MMC) in 113 (72%), meningocele in 3 (2%) and myelocystocele in 3 (2%)] and 36 had occult spina bifida [split cord malformation (SCM) without overt MMC sac (pure SCM) in 29 (19%) and midline dermal sinus in 7 (4.5%)]. Lipomeningomyelocele constituted 73 of the 113 cases of MMC (65%). Twenty cases of MMC (18%) had associated SCM (complex spina bifida). The total number of cases with SCM was 49 (32%). Twenty-four children with MMC presented with an operative scar from previous surgery, performed at the periphery. After a detailed clinical evaluation of all patients, craniospinal MRI was the preferable mode of investigation. All patients underwent surgery and were clinically assessed over a mean follow-up period of 3.6 years. RESULTS: MMC sac was the commonest skin manifestation seen in 89/155 cases (57%). Hypertrichosis and previous operative scar were noticed in 24 cases each (15%). Cutaneous hemangioma, skin tag and multiple neurofibroma were the other common superficial skin manifestations. Clinically, 103 patients (66.5%) had variable weakness of the lower limbs, and muscle atrophy was noticed in 56 cases (41%). Graded sensory loss, sphincteric dysfunction, trophic ulcer and backache were present in 89 (57%), 64 (36%), 17 (11%) and 9 cases (6%), respectively. Significant scoliosis in 56 cases (36%) and congenital talipes equinovarus in 51 cases (33%) were the most frequent neuroorthopedic deformities apart from high-arched foot, leg length discrepancy and flat foot. Common image findings were low-lying cord in 101 (65%), neural placode in 76/113 (49%), hydrosyrinx in 42 (27%), hydrocephalus in 71 (46%) and Chiari malformation in 62 cases (45%). The lumbosacral region in 56 cases (38%), followed by the lumbar region in 47 (30%), were the most common sites of occurrence of spina bifida. Of 71 hydrocephalic patients, 39 (55%) needed shunting before definitive surgery and 21 (30%) after the surgery. Eleven patients (15%) did not require shunting at all. CSF leak in 51 patients (33%), pseudomeningocele in 26 (17%), wound infection in 22 (14%) and meningitis in 13 (8%) were the most common postoperative complications. Two patients died in the postoperative period. During an average follow-up of 3.6 years (range 1.5-8 years), motor weakness improved in 47 children (45%) and remained static in 53 (52%), and 3 children showed deterioration in motor power. Sensory dysfunction improved in 43 (48%), remained static in 42 (47%) and deteriorated in 4 patients (4%). Sphincteric function clinically improved in 26 patients (41%) and was static in 38 (59%), and 6 patients (4%) had deterioration. Backache was dramatically relieved in all 9 patients with this complaint (100%). In 13 children with trophic ulcer (76%), it completely healed. CONCLUSION: A significant proportion of patients with open spinal dysraphism harbor an underlying SCM, an entity coined complex spina bifida (in our previous study). The incidence of hydrocephalus in spinal dysraphism is low in India in comparison to the Western world. Some patients with mild hydrocephalus on scan may not require a shunt operation. Surgical intervention should be early after entire neural axis screening by MRI.

Adolescent↗
PubMed2001

Prior coronary artery bypass surgery and risk of death among patients with ischemic left ventricular dysfunction.

BACKGROUND: Patients with ischemic LV dysfunction are at high risk of sudden death. However, no benefit from prophylactic defibrillator therapy was observed in a group of patients with LV dysfunction undergoing CABG (CABG Patch trial). Thus, the effect of CABG on future risk of sudden death in patients with LV dysfunction is of considerable interest. METHODS AND RESULTS: Mortality and modes of death in 5410 patients with ischemic LV dysfunction who were enrolled in the Studies of Left Ventricular Dysfunction (SOLVD) trials were evaluated. Outcomes of patients with (n=1870, 35%) versus without (n=3540) history of prior CABG were compared, and stratification by baseline ejection fraction (EF) values (<0.25, 0.25 to 0.30, and >0.30) was performed. Prior CABG was associated with a 25% (95% CI, 15% to 36%) reduction in risk of death and a 46% (95% CI, 30% to 58%) reduction in risk of sudden death independent of EF and severity of heart failure symptoms. As baseline EF declined, absolute reduction in risk of sudden death with prior CABG increased (P<0.01). No alteration in risk of death from progressive heart failure was observed with prior CABG. When these results were applied to a group of patients with LV dysfunction who had not undergone prior surgery (Coronary Artery Surgery Study Registry) predicted annual rates of death (8.2%) and sudden death (2.4%) were similar to those observed in the CABG Patch trial (7.9% and 2.3%, respectively). CONCLUSIONS: In patients with ischemic LV dysfunction, prior CABG is associated with a significant independent reduction in mortality. These results appear to account for the lack of benefit from defibrillator therapy in the CABG Patch trial.

Adult↗
PubMed2001

Electrophysiologic and clinical effects of angiotensin-converting enzyme inhibitors in patients with prior myocardial infarction, nonsustained ventricular tachycardia, and depressed left ventricular function. MUSTT Investigators. Multicenter UnSustained Tachycardia Trial.

Angiotensin-converting enzyme (ACE) inhibitors have been shown to reduce sudden cardiac death and all-cause mortality. They also may have direct antiarrhythmic properties. We retrospectively analyzed the data from the Multicenter UnSustained Tachycardia Trial (MUSTT), to determine the effects of ACE inhibitors on inducibility of sustained ventricular tachycardia and on sudden cardiac death and overall mortality in 2,087 patients with prior myocardial infarction, nonsustained ventricular tachycardia, and depressed left ventricular function. Results of electrophysiologic testing were compared by use of ACE inhibitors at baseline, and outcomes were compared between the 564 patients prescribed ACE inhibitors at discharge and the 1,523 patients who did not receive treatment. The inducibility of sustained ventricular tachycardia during electrophysiologic testing did not differ by baseline ACE inhibitor use (unadjusted p = 0.75). Patients discharged from hospital on ACE inhibitors had a lower ejection fraction, more extensive coronary artery disease, and fewer previous revascularizations at baseline. After adjustments for differences in baseline factors and initial hospitalization variables, there were no significant differences in total mortality (p = 0.47) or arrhythmic death or cardiac arrest (p = 0.51) with ACE inhibitor use at discharge over a median 43 months of follow-up.

Aged↗