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S Rajkumar

Publications and source records attributed to S Rajkumar.

At least 19 recordsLinked to original sources
PubMed2025

Development and validation of a high-density 'Amahysnp' genotyping array in grain amaranth (Amaranthus hypochondriacus).

BACKGROUND: Grain amaranth has recently gained global attention as a promising crop alternative to traditional cereals due to its nutritional value and adaptability to various growing conditions. Although gene banks conserve extensive collections of amaranth germplasm, the genomic and phenotypic characterization of these resources is limited, which hinders their full utilization in breeding programs. A major challenge is the lack of high-throughput genotyping assays essential for comprehensive genomic characterization and trait mapping. High-density SNP arrays have become standard tools for genome-wide analysis across multiple loci, enabling molecular breeding across a range of crop species. RESULTS: In this study, we developed a 64 K high-throughput SNP genotyping array named "AmahySNP", using Affymetrix® Axiom® technology. The array contains 64,069 high-density SNPs distributed across both genic (55.17%) and non-genic (44.83%) regions of the Amaranthus hypochondriacus genome. The genic region includes 8,879 genes, which consist of 4,830 single-copy genes and 4,049 multi-copy genes distributed across 16 scaffolds. These genes cover various functional regions, including exons (10.5%), introns (40.1%), 5'UTRs (1.6%), and 3'UTRs (2.9%), respectively. The AmahySNP array was effectively utilized for population structure analysis, genetic diversity studies, core development, and genome wide association studies (GWAS) in amaranth germplasm. A representative core set of 112 accessions was identified, which includes two released varieties (Annapurna and Suvarna) and 100 diverse accessions from 12 different regions, representing 12% of the total 917 accessions evaluated. Phylogenetic analysis revealed three major genetic clusters, independent of their geographical origins. GWAS conducted using 22,763 polymorphic SNPs from 540 genotypes identified 13 novel loci associated days to flowering (DTF) trait, seven of which were located within annotated genes. CONCLUSIONS: The AmahySNP 64 K SNP chip a valuable genomic tool for amaranth research and breeding with a strong potential to accelerate its genetic improvement. It enables high-throughput genotyping for a wide range of applications, including GWAS and other genomic studies, and will significantly advance the exploration of natural genetic variations. Ultimately, this resource will empower amaranth breeders to develop improved amaranth cultivars with enhanced crop yield, resilience, and nutritional quality, contributing to global food security and sustainable agriculture.

Amaranthus↗
PubMed2005

Oviposition deterrent and skin repellent activities of Solanum trilobatum leaf extract against the malarial vector Anopheles stephensi.

The leaf extract of Solanum trilobatum (Solanaceae) was tested under laboratory conditions for oviposition deterrent and skin repellent activities against the adult mosquito Anopheles stephensi. Concentrations of 0.01, 0.025, 0.05, 0.075 and 0.1% reduced egg laying by gravid females from 18 to 99% compared to ethanol-treated controls. In skin repellent tests, concentrations of 0.001, 0.005, 0.01, 0.015, and 0.02 % provided 70 to 120 minutes protection against mosquito bites, whereas the ethanol control provided only 2.2 minutes of protection. Both oviposition deterrent and skin repellent activity were dose dependent. The results suggest that the leaf extract of S. trilobatum is an effective oviposition deterrent and skin repellent against An. stephensi.

Animals↗
PubMed2005

Repellency of volatile oils from Moschosma polystachyum and Solanum xanthocarpum against filarial vector Culex quinquefasciatus say.

Volatile oils extracted by steam distillation from leaves of two plant species Moschosma polystachyum and Solanum xanthocarpum were evaluated in mosquito cages for their topical repellency effects against filarial vector Culex quinquefasciatus. The oil from M. polystachyum was tested at four different concentrations ranging from 1 to 4%. The 4% concentration gave 332.2 minutes protection whereas control gave only 4.4 minutes protection against mosquito bites. However, the volatile oil of S.xanthocarpum was tested from 2 to 8% concentration. The 8% concentration gave 311.4 minutes protection whereas control gave only 4.4 minutes protection against mosquito bites. The results suggest that the volatile oils of these two plant species were effective as repellents and gave more than 300 minutes of (>5 hour) protection against the bite of Cx. quinquefasciatus bite. Both volatile oils did not cause dermal irritation when applied to human skin. No adverse effects on human volunteers were observed after application. Therefore, both volatile oils can be applied as an effective personal protection measure against mosquito bites.

Animals↗
PubMed2004

Mosquitocidal activities of octacosane from Moschosma polystachyum Linn (lamiaceae).

The toxicity of the plant Moschosma polystachyum was evaluated against mosquito Culex quinquefasciatus. The crude leaf extract and active compound octacosane showed negligible mortality against early third instar larvae of Culex quinquefasciatus. The 24 h LC(50) value was observed at 153.2+/-1.3 mg/l and 7.2+/-1.7 mg/l for crude leaf extract and active compound octacosane, respectively. The repellent activity of active compound octacosane at 1.0 and 2.5 mg/cm(2) concentration gave 85.2+/-1.7 min and 54.6+/-2.3 min protection, respectively. The total percentage protection of octacosane was 96.2+/-0.9 at 2.5 mg/cm(2) and 86.4+/-1.3 at 1.0 mg/cm(2) concentration.

Alkanes↗
PubMed2001

Initiating care for untreated schizophrenia patients and results of one year follow-up.

A number of schizophrenia patients live untreated in the community in the developing countries. There is little recorded experience of how such patients would respond to treatment after years of untreated illness. A cohort of 72 never-treated chronic schizophrenia patents in Chennai, India were directed to attend a health facility. A substantial proportion of them (68%) came for treatment. Unemployed status of male patients, living in a joint family setting and families initially unaware of the psychiatric nature of the problem were the factors that related to failure to seek treatment. Patient's sex, age, education, marital status, economic status, age at onset and duration of illness, degree of disability and clinical symptoms (except self-neglect) were not related to taking treatment. Those who attended were treated with typical antipsychotic drugs and followed up for one year. Evaluation was done using the Present State Examination and Psychiatric History and Sociodemographic Schedule and Disability Assessment Schedule. The clinical outcome was good (Best Remission) in 29%. There was no impairment in social functioning in 35% and 51% has no impairment in occupational functioning at the end of one year.

Adult↗
PubMed2001

Isolation of group A beta-hemolytic streptococci in the tonsillopharynx of school children in Madras City and correlation with their clinical features.

Today, rheumatic fever is the most common cause of heart disease in children and young adults, and it accounts for about half of all cardiovascular diseases causing death in the first four decades of life, in India. In the present study, conducted during 1991-1992 at Chennai, India, a total of 666 school girls aged 5-15 years were examined clinically for one or more of the following signs and symptoms: repeated sore throat, joint pain/swelling, epistaxis, chest pain, breathlessness, palpitation, abdominal pains, etc. Out of the 666 children screened, 124 were recruited for the present study, based on their meeting one or more of the above mentioned clinical criteria. They were screened for the presence of group A beta-hemolytic streptococci, and for antistreptolysin O and C-reactive protein. Thus, the aim of the present study was to reduce the load of streptococcal infection and the consequent risk of developing rheumatic fever and rheumatic heart disease. In the present study group, 89.5% of the children indicated a history of repeated sore throat. However, only 4.0% of the children in the study group were positive for group A beta-hemolytic streptococci. The antistreptolysin O and C-reactive protein levels were higher in 11- to 15-year-old patients than in 5- to 10-year-old patients in the study group.

Adenoids↗
PubMed2000

Beta-and gamma-turns in proteins revisited: a new set of amino acid turn-type dependent positional preferences and potentials.

The number of beta-turns in a representative set of 426 protein three-dimensional crystal structures selected from the recent Protein Data Bank has nearly doubled and the number of gamma-turns in a representative set of 320 proteins has increased over seven times since the previous analysis. Beta-turns (7153) and gamma-turns (911) extracted from these proteins were used to derive a revised set of type-dependent amino acid positional preferences and potentials. Compared with previous results, the preference for proline, methionine and tryptophan has increased and the preference for glutamine, valine, glutamic acid and alanine has decreased for beta-turns. Certain new amino acid preferences were observed for both turn types and individual amino acids showed turn-type dependent positional preferences. The rationale for new amino acid preferences are discussed in the light of hydrogen bonds and other interactions involving the turns. Where main-chain hydrogen bonds of the type NH(i + 3) --> CO(i) were not observed for some beta-turns, other main-chain hydrogen bonds or solvent interactions were observed that possibly stabilize such beta-turns. A number of unexpected isolated beta-turns with proline at i + 2 position were also observed. The NH(i + 2) --> CO(i) hydrogen bond was observed for almost all gamma-turns. Nearly 20% classic gamma-turns and 43% inverse gamma-turns are isolated turns.

Amino Acid Motifs↗
PubMed1999

Abnormal cytogenetics predict poor survival after high-dose therapy and autologous blood cell transplantation in multiple myeloma.

We compared the prognostic value of conventional cytogenetic analysis and established factors such as beta2-microglobulin and plasma cell labeling index in 70 patients undergoing autologous blood cell transplantation for multiple myeloma. Patients underwent transplantation 5 to 88 months (median, 20 months) after the initial diagnosis of myeloma. Factors studied were age, sex, beta2-microglobulin, response to prior therapy, plasma cell labeling index, cytogenetic analysis, bone marrow plasma cell percentage, lactate dehydrogenase and C-reactive protein. Twenty-eight of 65 patients (43%) had abnormal marrow cytogenetics. Overall survival measured from transplantation was significantly better in patients with normal cytogenetics than in those with abnormal cytogenetics (median survival, 25 vs 12 months, P = 0.003). Progression-free survival was better, with median times of 12 vs7 months, respectively (P = 0.005); overall survival measured from the time myeloma was first diagnosed was also longer, with median survivals of 62 and 39 months, respectively (P = 0.001). Median plasma cell labeling index was 1.5% in patients with abnormal cytogenetics and 0. 2% in those with normal cytogenetics (P < 0.001). Abnormal bone marrow cytogenetics predict poor survival after blood cell transplantation for myeloma. There is a significant correlation between abnormal cytogenetics and high plasma cell labeling index, suggesting that certain cytogenetic abnormalities may offer a proliferative advantage to myeloma cells.

Adult↗
PubMed1999

Are risk factors for suicide universal? A case-control study in India.

OBJECTIVE: The majority of suicides in India occur in the young. Indian society, religion and culture are very different to those in the West. The aim of the present study was to identify the risk factors for completed suicide. METHOD: A population-based case-control study employing the 'psychological autopsy' technique was conducted. In total, 100 completed suicides and 100 neighbourhood controls were studied. RESULTS: The odds ratios for the risk factors were 19.5 (CI, 7.32-73.35) for presence of an Axis I disorder, 12.75 (CI, 4.69-48.59) for family history of psychopathology and 15.1 (CI, 2.4-93.9) for life events in the previous month. CONCLUSION: The presence of an Axis I disorder, family history of psychopathology and recent life events were all found to be significant risk factors. These findings suggest that risk factors for completed suicide are universal across countries and cultures.

Adolescent↗
PubMed1998

Schizophrenic patients who were never treated--a study in an Indian urban community.

BACKGROUND: A significant number of patients with severe psychiatric disorders remain untreated in the community although health services are available. The factors related to non-treatment are not well understood. METHOD: A door-to-door survey was conducted on an Indian urban population of 100,000 using standardized screening and clinical instruments as a part of a larger epidemiological study. Treatment status was determined from multiple sources of information. RESULTS: Nearly one-third of 261 schizophrenia patients were found never to have received treatment. They were older in age and ill for a longer duration than those who had been treated and were more symptomatic and severely disabled. They were more often uneducated and divorced and lived with larger extended/joint families. This last factor was considered as being the important factor in determining whether the patient received treatment. CONCLUSION: The larger extended/joint family, which was able to compensate and cope with the dysfunctional member, seemed to be the crucial factor related to non-treatment of the schizophrenic patient.

Adult↗
PubMed1997

Prevalence of dementia in a rural setting: A report from India.

A study to estimate the prevalence of dementia in a rural population was conducted in a community located on the outskirts of Madras city in South India. Seven hundred and fifty elderly 60 years of age and older, selected using the cluster sampling technique, were interviewed using the Geriatric Mental State schedule (GMS). The prevalence of dementia was 3.5%, the percentage increasing with age. These rural prevalence estimates were higher than in urban settings (WHO multicentre study on cognitive impairment and dementia in developed and developing countries, unpublished) and male/female differences were negligible. The difficulties associated with the use of the GMS in a non-literature rural population are discussed. The implications of these findings for India's growing elderly population are highlighted.

Aged↗
PubMed1994

Ten-year course of schizophrenia--the Madras longitudinal study.

Ninety first-episode patients fulfilling ICD-9 criteria for schizophrenia were followed up prospectively for 10 years. Complete assessments were possible on 76. The pattern of illness was good in 67% of the cases, and the commonest patterns was one with recurrent episodes. Predictors of poor course and longer time spent in psychosis were identified. All positive and negative symptoms showed a steep decline at the end of 10 years. The results are discussed in the context of longitudinal research on the course of schizophrenia in developing countries.

Adult↗
PubMed1992

Gender differences in schizophrenia. Results of a follow-up study from India.

As part of the study on 'Factors affecting the course and outcome of schizophrenia' at Madras, India, 96 schizophrenic patients who fulfilled Feighner's criteria were followed up closely. Of these, 67 patients who completed 5 years of follow-up were studied with respect to gender differences in sociodemographic and clinical variables at inclusion and follow-up, course of illness and outcome. Women were found to have a better outcome. The various factors contributing to this are discussed in the context of the Indian setting.

Adult↗
PubMed1989

Coping with symptoms of relapse in schizophrenia.

A pilot study is reported of 30 chronic schizophrenic patients at the psychiatric out-patient facility of Government General Hospital, Madras, India. The objectives of the study were to assess the patients' perception of prodromata of relapse and their coping mechanisms. Patients were questioned on these aspects, using a semi-structured interview guide. The study showed a high degree of perception of prodromal signs amongst the cohort. Only 4 patients were unable to perceive any prodromata of relapse. Most commonly noted prodromal symptoms were disturbed sleep and slowness and underactivity. Patients had also resorted to various coping measures such as internal dialogue and talking to a close relative or friend. The study has clearly proved that Indian schizophrenic patients are perceptive of prodromata of relapse and developed self-help methods. These methods, if properly identified, could be incorporated in psychosocial intervention programmes.

Adaptation, Psychological↗
PubMed1989

Alexithymic characteristics in rheumatoid arthritis: a controlled study.

Forty rheumatoid arthritis (RA) patients diagnosed by rigid criteria were evaluated for alexithymic characteristics using the Beth Israel Hospital Psychosomatic Questionnaire (BIQ) and the Toronto Alexithymia Scale (TAS). 40 healthy subjects matched with RA patients on sociodemographic variables served as controls. RA patients scored significantly higher on the BIQ and TAS compared to controls. The two scales correlated in the expected direction. Using the TAS cutoff score of 74 and above, 11 RA patients (27.5%) were identified as alexithymic. RA patients with greater functional impairment showed significantly higher alexithymia scores.

Adult↗
PubMed1989

Factors associated with the course and outcome of schizophrenia in India. Results of a two-year multicentre follow-up study.

The paper describes the two-year follow-up results from 323 out of 386 patients fulfilling a modified version of Feighner's criteria for diagnosis of schizophrenia, in Lucknow, Vellore, and Madras. There was remission in 66% of cases. Short duration of illness, consistent compliance with medication, positive attitudes of relatives and neighbours, absence of economic difficulties, increase in religious activities on the part of patients, a rural background, and a non-schizoid pre-morbid personality were associated with good outcome. Features of depression, dangerous behaviour, and absence of agitation were associated with poor outcome.

Adolescent↗