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Biomedical subjects

R P Singh

Publications and source records attributed to R P Singh.

At least 19 recordsLinked to original sources
PubMed2007

Outcome of phacoemulsification in patients with uveitis.

AIMS: To examine the visual outcome and identify risk factors for postoperative uveitis, macular oedema and neodymium-doped yttrium aluminium garnet (Nd:YAG) capsulotomy after phacoemulsification and intraocular lens (IOL) implantation in patients with uveitis. METHOD: This is a retrospective review of the medical records of 101 eyes of 101 patients. One eye was randomly selected for inclusion in patients who had bilateral surgery. Patients with juvenile arthritis, keratouveitis and lymphoma-associated uveitis were excluded. RESULTS: At the first postoperative and final visits, visual acuity was significantly better (p<0.001), and 64.4% and 71.3% of patients, respectively, had achieved >or=2 Snellen's lines of visual improvement. The cumulative probability of doubling of the visual angle was 52% over 6 years of follow-up, and this occurred at a higher rate in the presence of preoperative retinal or optic nerve lesions (HR (95% CI) 4.49 (1.41 to 14.29)). Within 3 months after operation, uveitis was more likely to develop in female patients (OR (95% CI) 6.21 (1.41 to 27.43)) and in the presence of significant intraoperative posterior synechiae (OR (95% CI) 8.43 (1.09 to 65.41)); macular oedema was more likely to develop in patients who developed postoperative uveitis (OR (95% CI) 7.45 (1.63 to 34.16)). Nd:YAG capsulotomy occurred at a higher rate in patients aged <or=55 years (HR (95% CI) 2.28 (1.06, 4.93)) and in those with hydrogel IOLs (HR (95% CI) 3.71 (1.04 to 13.20)), and occurred at a lower rate in patients who had prophylactic systemic corticosteroids (HR (95% CI) 0.25 (0.11 to 0.59)), with plate-haptic silicone IOLs (HR (95% CI) 0.23 (0.08 to 0.64)) and three-piece silicone IOLs (HR (95% CI) 0.19 (0.05 to 0.74)) in comparison to those with polymethylmethacrylate IOLs. CONCLUSION: Most patients with uveitis achieve improved visual acuity after phacoemulsification, but an increasing rate of visual loss is observed in those with pre-existent macular or optic nerve lesions. Identifying patients who are at risk of postoperative complications should help in patient counselling and to pre-empt these complications by using preoperative prophylactic corticosteroids, careful IOL selection and postoperative intensive corticosteroids.

Adolescent↗
PubMed2006

Development of an indirect ELISA for the detection of antibodies against Peste-des-petits-ruminants virus in small ruminants.

Peste des petits ruminants (PPR) is an acute, febrile, highly contagious and economically important viral disease of small ruminants. A polyclonal antibody based indirect ELISA was developed for detection of antibodies to PPR virus in the serum samples of goats and sheep using purified PPR viral antigen propagated in Vero cell culture. A threshold (cut-off) value was set as twice the mean of the negative population based on the distribution of known negative serum samples in respect of PPR virus antibodies in the test. A total of 1544 serum samples from goats and sheep were screened by indirect ELISA and competitive ELISA. The indirect ELISA compared very well with competitive ELISA, with a high degree of specificity (95.09%) and sensitivity (90.81%). When compared with virus neutralization test, the present assay had 100% specificity and 80% sensitivity. With serum samples, the assay could clearly differentiate animals from the infected population from uninfected ones. These results suggest that the indirect ELISA may be a good alternative tool to competitive ELISA for seroepidemiological surveys.

Animals↗
PubMed2006

Molecular genetic characterization of the Lr34/Yr18 slow rusting resistance gene region in wheat.

Wheat expressed sequence tags (wESTs) were identified in a genomic interval predicted to span the Lr34/Yr18 slow rusting region on chromosome 7DS and that corresponded to genes located in the syntenic region of rice chromosome 6 (between 2.02 and 2.38 Mb). A subset of the wESTs was also used to identify corresponding bacterial artificial chromosome (BAC) clones from the diploid D genome of wheat (Aegilops tauschii). Conservation and deviation of micro-colinearity within blocks of genes were found in the D genome BACs relative to the orthologous sequences in rice. Extensive RFLP analysis using the wEST derived clones as probes on a panel of wheat genetic stocks with or without Lr34/Yr18 revealed monomorphic patterns as the norm in this region of the wheat genome. A similar pattern was observed with single nucleotide polymorphism analysis on a subset of the wEST derived clones and subclones from corresponding D genome BACs. One exception was a wEST derived clone that produced a consistent RFLP pattern that distinguished the Lr34/Yr18 genetic stocks and well-established cultivars known either to possess or lack Lr34/Yr18. Conversion of the RFLP to a codominant sequence tagged site (csLV34) revealed a bi-allelic locus, where a variant size of 79 bp insertion in an intron sequence was associated with lines or cultivars that lacked Lr34/Yr18. This association with Lr34/Yr18 was validated in wheat cultivars from diverse backgrounds. Genetic linkage between csLV34 and Lr34/Yr18 was estimated at 0.4 cM.

Chromosome Mapping↗
PubMed2006

Identification of T-helper and linear B epitope in the hypervariable region of nucleocapsid protein of PPRV and its use in the development of specific antibodies to detect viral antigen.

Peste des petits ruminants is a highly contagious viral disease of small ruminants making its diagnosis difficult from the similar symptoms of Rinderpest. Computer based prediction algorithms was applied to identify antigenic determinants on the nucleocapsid (N) protein of PPRV. Specificity and antigenicity of each peptide was evaluated by solid phase ELISA. Six specific peptide sequences were evaluated in multiple antigenic peptide (MAP) form and immune response was evaluated by supplementing universal T-helper epitope human IL-1beta peptide (VQGEESNDK, amino acids 163-171). Out of the six peptides 19mer sequence corresponding to 454-472 region of N protein of PPRV was found to be highly immunogenic and specific to PPRV. Evaluation of overlapping peptides differing in length for this 452-472 region, showed minimum length of 14 amino acid residues were required for the stable affinity binding of antigen-antibody. The results of immunization and indirect ELISA indicated the presence of T-helper epitope at the N-terminal end and linear B epitope at the C-terminal region of 454-472 19mer of nucleocapsid peptide of PPRV-nucleocapsid protein. The antipeptide antibodies developed against this region showed specificity to PPRV antigen differentiating it from RPV when used in indirect ELISA and western blot analysis.

Amino Acid Sequence↗
PubMed2006

Production of lactic acid with loofa sponge immobilized Rhizopus oryzae RBU2-10.

Lactic acid production by Rhizopus oryzae RBU2-10 immobilized in loofa sponge was evaluated. Shape and texture of loofa sponge, which was obtained from the mature dried fruit of Luffa cylindrica, remained intact after its treatment with buffers of varying pH and following its repeated autoclaving for up to four cycles (121 degrees C, 20 min per cycle). The medium having four pieces of loofa sponge (1.008 cm(3)) per 100 ml medium and inoculated with 3 x1 0(6) spores ml(-1) resulted maximum production (80.75 g l(-1)) of lactic acid in 48 h of fermentation. Repeated batch fermentation for lactic acid production could be carried out for 10 cycles. Remarkably higher levels of productivity (1.66-1.84 g l(-1)h(-1)) was obtained during first five cycles of fermentation with a maximum productivity (1.84 g l(-1)h(-1)) obtained during third cycle of fermentation.

Animals↗
PubMed2006

Simultaneous quantification of alpha-/beta-diastereomers of arteether, sulphadoxine and pyrimethamine: a promising anti-relapse antimalarial therapeutic combination, by liquid chromatography tandem mass spectrometry.

A rapid, sensitive, selective and specific HPLC/ESI-MS/MS assay method was developed and validated for the simultaneous quantitation of alpha-/beta-diastereomers of arteether (AE), sulphadoxine (SDX) and pyrimethamine (PYR) in rat blood plasma using propyl ether analogue of beta-arteether as internal standard. The method involved a single-step, liquid-liquid extraction with ethyl acetate and the analytes were chromatographed on a C18 chromatographic column by isocratic elution with methanol:ammonium acetate buffer (10 mM, pH 4) (90:10%, v/v) and analyzed by tandem mass spectrometry. The run time was 4.5 min and the weighted (1/x2) calibration curves were linear over a range of 0.78-400 ng ml-1. The method was validated fully and the lower limit of quantification (LLOQ) in plasma was 0.78 ng ml-1 for all the analytes. The intra- and inter-day precision and accuracy were found to be well within the acceptable limits (<15%) and the analytes were stable after three freeze-thaw (f-t) cycles. The absolute recoveries were consistent and reproducible. The assay method was applied to pre-clinical pharmacokinetic interaction studies of alpha-/beta-AE, SDX and PYR in rats.

Animals↗
PubMed2006

Molecular mapping of stripe rust resistance gene YrCH42 in Chinese wheat cultivar Chuanmai 42 and its allelism with Yr24 and Yr26.

Stripe rust, caused by Puccinia striiformis f. sp. tritici (PST), is one of the most devastating diseases in common wheat (Triticum aestivum L.) worldwide. The objectives of this study were to map a stripe rust resistance gene in Chinese wheat cultivar Chuanmai 42 using molecular markers and to investigate its allelism with Yr24 and Yr26. A total of 787 F2 plants and 186 F3 lines derived from a cross between resistant cultivar Chuanmai 42 and susceptible line Taichung 29 were used for resistance gene tagging. Also 197 F2 plants from the cross Chuanmai 42xYr24/3*Avocet S and 726 F2 plants from Chuanmai 42xYr26/3*Avocet S were employed for allelic test of the resistance genes. In all, 819 pairs of wheat SSR primers were used to test the two parents, as well as resistant and susceptible bulks. Subsequently, nine polymorphic markers were employed for genotyping the F2 and F3 populations. Results indicated that the stripe rust resistance in Chuanmai 42 was conferred by a single dominant gene, temporarily designated YrCH42, located close to the centromere of chromosome 1B and flanked by nine SSR markers Xwmc626, Xgwm273, Xgwm11, Xgwm18, Xbarc137, Xbarc187, Xgwm498, Xbarc240 and Xwmc216. The resistance gene was closely linked to Xgwm498 and Xbarc187 with genetic distances of 1.6 and 2.3 cM, respectively. The seedling tests with 26 PST isolates and allelic tests indicated that YrCH42, Yr24 and Yr26 are likely to be the same gene.

Alleles↗
PubMed2006

Silymarin and silibinin cause G1 and G2-M cell cycle arrest via distinct circuitries in human prostate cancer PC3 cells: a comparison of flavanone silibinin with flavanolignan mixture silymarin.

Here, we assessed and compared the anticancer efficacy and associated mechanisms of silymarin and silibinin in human prostate cancer (PCA) PC3 cells; silymarin is comprised of silibinin and its other stereoisomers, including isosilybin A, isosilybin B, silydianin, silychristin and isosilychristin. Silymarin and silibinin (50-100 microg/ml) inhibited cell proliferation, induced cell death, and caused G1 and G2-M cell cycle arrest in a dose/time-dependent manner. Molecular studies showed that G1 arrest was associated with a decrease in cyclin D1, cyclin D3, cyclin E, cyclin-dependent kinase (CDK)4, CDK6 and CDK2 protein levels, and CDK2 and CDK4 kinase activity, together with an increase in CDK inhibitors (CDKIs) Kip1/p27 and Cip1/p21. Further, both agents caused cytoplasmic sequestration of cyclin D1 and CDK2, contributing to G1 arrest. The G2-M arrest by silibinin and silymarin was associated with decreased levels of cyclin B1, cyclin A, pCdc2 (Tyr15), Cdc2, and an inhibition of Cdc2 kinase activity. Both agents also decreased the levels of Cdc25B and cell division cycle 25C (Cdc25C) phosphatases with an increased phosphorylation of Cdc25C at Ser216 and its translocation from nucleus to the cytoplasm, which was accompanied by an increased binding with 14-3-3beta. Both agents also increased checkpoint kinase (Chk)2 phosphorylation at Thr68 and Ser19 sites, which is known to phosphorylate Cdc25C at Ser216 site. Chk2-specific small interfering RNA largely attenuated the silymarin and silibinin-induced G2-M arrest. An increase in the phosphorylation of histone 2AX and ataxia telangiectasia mutated was also observed. These findings indicate that silymarin and silibinin modulate G1 phase cyclins-CDKs-CDKIs for G1 arrest, and the Chk2-Cdc25C-Cdc2/cyclin B1 pathway for G2-M arrest, together with an altered subcellular localization of critical cell cycle regulators. Overall, we observed comparable effects for both silymarin and silibinin at equal concentrations by weight, suggesting that silibinin could be a major cell cycle-inhibitory component in silymarin. However, other silibinin stereoisomers present in silymarin also contribute to its efficacy, and could be of interest for future investigation.

Carcinoma↗
PubMed2006

Molecular tagging of stripe rust resistance gene YrZH84 in Chinese wheat line Zhou 8425B.

Stripe rust, caused by Puccinia striiformis f. sp. tritici (PST), is one of the most damaging diseases in common wheat (Triticum aestivum L.). With the objective of identifying and tagging new genes for resistance to stripe rust, F1, F2 and F3 populations from the cross Zhou 8425B/Chinese Spring were inoculated with Chinese PST isolate CYR32 in the greenhouse. A total of 790 SSR primers were used to test the parents and resistant and susceptible bulks. The resulting seven polymorphic markers on chromosome 7BL were used for genotyping F2 and F3 populations. Results indicated that Zhou 8425B carries a single dominant resistance gene, temporarily designated YrZH84, closely linked to SSR markers Xcfa2040-7B and Xbarc32-7B with genetic distances of 1.4 and 4.8 cM, respectively. In a seedling test with 25 PST isolates, the reaction patterns of YrZH84 were different from those of lines carrying Yr2 and Yr6. It was concluded that YrZH84 is probably a new stripe rust resistance gene.

Cloning, Molecular↗
PubMed2006

One-step multiplex RT-PCR assay for the detection of peste des petits ruminants virus in clinical samples.

A single-tube one-step multiplex RT-PCR was standardized to amplify both 337 bp and 191 bp fragments of N and M genes of peste des petits ruminants virus (PPRV), respectively, and only a 337 bp fragment of N gene of Rinderpest virus (RPV). The RT-PCR using purified viral RNA was easily adopted for direct detection of PPRV in clinical field samples and its differentiation from RPV. The amplified N and M gene products were confirmed to be PPRV- and RPV-specific by their size in 1.5% agarose gel and restriction analysis. In the assay, the Qiagen one-step RT-PCR kit containing the Ominiscript and Sensiscript reverse transcriptases and Hot star Taq DNA polymerase was utilized. The sensitivity of the assay was found to be 100 fg of PPRV RNA. Compared with a two-step assay, the one-step assay is easier and time-saving as it requires just a single buffer for both reactions, reverse transcription (RT) and PCR. In experimentally infected goats, PPRV was detectable by the one-step RT-PCR in nasal and ocular swabs 7-17 days post infection (p.i.). and in oral swabs 7-15 days p.i. Out of 32 clinical field samples tested, 18 were positive by sandwich ELISA (S-ELISA), while 22 were positive by the one-step RT-PCR.

Animals↗
PubMed2006

Sequence analysis of the haemagglutinin and fusion protein genes of peste-des-petits ruminants vaccine virus of Indian origin.

The amino acid composition of the two surface proteins of peste-des-petits ruminants vaccine virus belonging to lineage four from India were deduced from the nucleotide sequence. The fusion (F) protein gene of PPRV Sungri/96 is 2405 nucleotides long and in relation to the length, it is 80 nucleotides longer than that of PPRV Nigeria/75/1 which are found to be present at the 5'UTR of this virus. The complete F gene alignment with other morbillivirus reveals a homology of 89% with PPRV/Nigeria/75/1 and 48-51% with other morbilliviruses. The F protein of PPRV Sungri/96 exhibited characteristics similarity to those of other morbillivirus F proteins. The overall amino acid similarity with its counterpart PPRV Nigeria/75/1 was 96%; with other morbilliviruses it is 65-74%. The PPRV Sungri/96 haemagglutinin (H) protein gene is 1954 nucleotides long and showed a sequence homology of 90.7% with PPRV/Nigeria/75/1 and with other morbilliviruses it ranged from 33% to 45%. At amino acids level, PPRV Sungri/96 showed a homology of 92.3% with PPRV/Nigeria/75/1 and 34-49% with other morbilliviruses. The phylogenetic tree constructed for F and H gene reveals four separate groups which is very similar to that found in other genes. To the best of our knowledge this is the first report describing the F and H genes of an Indian isolate.

Amino Acid Sequence↗
PubMed2006

Bioconversion of grape must into modulated gluconic acid production by Aspergillus niger ORS-4.410.

AIMS: Analysis of regulators for modulated gluconic acid production under surface fermentation (SF) condition using grape must as the cheap carbohydrate source, by mutant Aspergillus niger ORS-4.410. Replacement of conventional fermentation condition by solid-state surface fermentation (SSF) for semi-continuous production of gluconic acid by pseudo-immobilization of A. niger ORS-4.410. METHODS AND RESULTS: Grape must after rectification was utilized for gluconic acid production in batch fermentation in SF and SSF processes using mutant strain of A. niger ORS-4.410. Use of rectified grape must led to the improved levels of gluconic acid production (80-85 g l(-1)) in the fermentation medium containing 0.075% (NH4)2HPO4; 0.1% KH2PO4 and 0.015% MgSO4.7H2O at an initial pH 6.6 (+/-0.1) under surface fermentation. Gluconic acid production was modulated by incorporating the 2% soybean oil, 2% starch and 1% H2O2 in fermentation medium at continuously high aeration rate (2.0 l min(-1)). Interestingly, 95.8% yield of gluconic acid was obtained when A. niger ORS-4.410 was pseudo-immobilized on cellulose fibres (bagasse) under SSF. Four consecutive fermentation cycles were achieved with a conversion rate of 0.752-0.804 g g(-1) of substrate into gluconic acid under SSF. CONCLUSIONS: Use of additives modulated the gluconic acid production under SF condition. Semi-continuous production of gluconic acid was achieved with pseudo-immobilized mycelia of A. niger ORS-4.410 having a promising yield (95.8%) under SSF condition. SIGNIFICANCE AND IMPACT OF THE STUDY: The bioconversion of grape must into modulated gluconic acid production under SSF conditions can further be employed in fermentation industries by replacing the conventional carbohydrate sources and expensive, energy consuming fermentation processes.

Aspergillus niger↗
PubMed2006

Management of subretinal macular haemorrhage by direct administration of tissue plasminogen activator.

BACKGROUND/AIMS: Recent studies on the treatment of acute subretinal macular haemorrhage have shown that the volume of the clot and the time to evacuation have strong prognostic factors for visual outcome. A novel technique for surgical evacuation of these lesions involves direct injection of tissue plasminogen activator (t-PA) into the haematoma using pars plana vitrectomy. The aim of this study was to evaluate the clinical outcomes of this recently described procedure. METHODS: 17 consecutive patients with subretinal macular haemorrhages caused by age related macular degeneration were enrolled. Patient demographics, acuities, and fluorescein angiograms were obtained for all evaluations. All patients underwent complete three port pars plana vitrectomy to enable direct cannulation of the subretinal space and injection of 48 mug of t-PA, partial fluid-air exchange, 1 hour face up supine positioning postoperatively, followed by upright positioning overnight. RESULTS: 88% of patients within the study had stabilisation or improvement of visual acuity. Nine patients had total clearing of the macular haemorrhage and eight patients had subtotal clearing. Two patients had recurrence of the haemorrhage after the procedure and one patient underwent repair for retinal detachment. Occult lesions demonstrated similar outcomes to classic or predominately classic lesions. Nine patients required no therapy after the study to treat subfoveal neovascularisation. CONCLUSIONS: This study represents one of the largest case series to date showing that direct injection of subretinal t-PA with air-fluid exchange only and no intraoperative clot lysis period can have favourable results.

Acute Disease↗
PubMed2006

Characterization of genetic loci conferring adult plant resistance to leaf rust and stripe rust in spring wheat.

Leaf (brown) and stripe (yellow) rusts, caused by Puccinia triticina and Puccinia striiformis, respectively, are fungal diseases of wheat (Triticum aestivum) that cause significant yield losses annually in many wheat-growing regions of the world. The objectives of our study were to characterize genetic loci associated with resistance to leaf and stripe rusts using molecular markers in a population derived from a cross between the rust-susceptible cultivar 'Avocet S' and the resistant cultivar 'Pavon76'. Using bulked segregant analysis and partial linkage mapping with AFLPs, SSRs and RFLPs, we identified 6 independent loci that contributed to slow rusting or adult plant resistance (APR) to the 2 rust diseases. Using marker information available from existing linkage maps, we have identified additional markers associated with resistance to these 2 diseases and established several linkage groups in the 'Avocet S' x 'Pavon76' population. The putative loci identified on chromosomes 1BL, 4BL, and 6AL influenced resistance to both stripe and leaf rust. The loci on chromosomes 3BS and 6BL had significant effects only on stripe rust, whereas another locus, characterized by AFLP markers, had minor effects on leaf rust only. Data derived from Interval mapping indicated that the loci identified explained 53% of the total phenotypic variation (R2) for stripe rust and 57% for leaf rust averaged across 3 sets of field data. A single chromosome recombinant line population segregating for chromosome 1B was used to map Lr46/Yr29 as a single Mendelian locus. Characterization of slow-rusting genes for leaf and stripe rust in improved wheat germplasm would enable wheat breeders to combine these additional loci with known slow-rusting loci to generate wheat cultivars with higher levels of slow-rusting resistance.

Basidiomycota↗
PubMed2006

Prevalence of anemia among pregnant women and adolescent girls in 16 districts of India.

BACKGROUND: Nutritional anemia is one of India's major public health problems. The prevalence of anemia ranges from 33% to 89% among pregnant women and is more than 60% among adolescent girls. Under the anemia prevention and control program of the Government of India, iron and folic acid tablets are distributed to pregnant women, but no such program exists for adolescent girls. OBJECTIVE: To assess the status of anemia among pregnant women and adolescent girls from 16 districts of 11 states of India. METHODS: A two-stage random sampling method was used to select 30 clusters on the basis of probability proportional to size. Anemia was diagnosed by estimating the hemoglobin concentration in the blood with the use of the indirect cyanmethemoglobin method. RESULTS: The survey data showed that 84.9% of pregnant women (n = 6,923) were anemic (hemoglobin < 110 g/L); 13.1% had severe anemia (hemoglobin < 70 g/L), and 60.1% had moderate anemia (hemoglobin > or = 70 to 100 g/L). Among adolescent girls (n = 4,337)from 16 districts, the overall prevalence of anemia (defined as hemoglobin < 120 g/L) was 90.1%, with 7.1% having severe anemia (hemoglobin < 70 g/L). CONCLUSIONS: Any intervention strategy for this population must address not only the problem of iron deficiency, but also deficiencies of other micronutrients, such as B12 and folic acid and other possible causal factors.

Adolescent↗