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Biomedical subjects

P Saravanan

Publications and source records attributed to P Saravanan.

At least 19 recordsLinked to original sources
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

Development and characterization of a stable vero cell line constitutively expressing Peste des petits ruminants virus (PPRV) hemagglutinin protein and its potential use as antigen in enzyme-linked immunosorbent assay for serosurveillance of PPRV.

We developed and characterized a stable Vero cell line constitutively expressing Peste des petits ruminants virus (PPRV) hemagglutinin (H) protein and assessed its potential use as diagnostic antigen in enzyme-linked immunosorbent assay (ELISA). PPRV H gene of the vaccine strain (Sungri-96) was amplified by reverse transcription (RT)-PCR, cloned into a eukaryotic expression vector (pTarget), and subsequently transfected and expressed in Vero cells. A stable Vero cell line was developed after 20 repeated passages by using G418 antibiotic selection pressure (400 to 600 microg/ml). The integration of PPRV H gene in the Vero cell genome and its genomic transcription were confirmed by PCR and RT-PCR assays, respectively, and the 70-kDa PPRV H protein was characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting. The recombinant protein reacted specifically with PPRV anti-H neutralizing monoclonal and polyclonal antibody in competitive, sandwich, and indirect ELISA, respectively, indicating that the native form of the protein was expressed. Evaluation of the protein in competitive ELISA and indirect ELISA vis a vis whole virus was done using 306 and 146 goat field serum samples, respectively; comparable results were obtained with high degrees of relative diagnostic specificity (93.53% and 100%, respectively) and sensitivity (99.04% and 79.16%, respectively). This study shows that the PPRV H protein could be a sustainable source of safe antigen in countries of nonendemicity without the need to handle infectious virus for serodiagnosis.

Animals↗
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↗
PubMed2005

Analysis of the matrix protein gene sequence of the Asian lineage of peste-des-petits ruminants vaccine virus.

The M gene nucleotide sequence of an Indian peste-des-petits ruminants (PPRV) vaccine virus ("PPRV Sungri/96") belonging to Asian lineage was determined. The gene is 1476 nucleotides long with a single open reading frame (ORF). The nucleotide and predicted amino acid sequence was compared with the homologous region of the African Lineage Vaccine virus "PPRV/Nigeria/75/1". The nucleotide sequence of the "PPRV Sungri/96" was 86% identical to that of "PPRV/Nigeria/75/1", while a homology of 93% and 95% could be observed in the ORF and amino acids level, respectively. The M gene encodes a protein of 335 amino acids, with a predicted molecular weight (MW) of 37.8 kDa. The ORF is flanked by a 3' untranslated region of 436 nucleotides and a high level of sequence divergence (approximately 30%) could be observed in this region between the vaccine viruses of Asian and African lineages. A high degree of conservation of several amino acids of this protein observed previously was also confirmed in this study.

Amino Acid Sequence↗
PubMed2005

A survey of resuscitation training needs of senior anaesthetists.

Resuscitation skills are a fundamental part of anaesthetic practice. Anaesthetists are involved in performing resuscitation and training of other staff in resuscitation techniques. However, very few senior anaesthetists attend the Resuscitation Council (UK)/European Resuscitation Council [RC (UK)/ERC] advanced life support (ALS) course. We have surveyed the views of consultant anaesthetists in one region of the UK. The results show that although they are involved in training, very few attend cardiac arrests. Most have not, and will not, attend the ALS course but would prefer shorter regular resuscitation updates, especially in those skills that they no longer use.

Anesthesiology↗
PubMed2004

A simple stereocontrolled synthesis of salinosporamide A.

A simple and effective stereocontrolled synthesis of salinosporamide A has been developed. This process, the first synthesis of salinosporamide A, is capable of providing the compound in substantial quantities for further biological studies. Salinosporamide A was of special interest as a synthetic target because of its potent in vitro cytotoxic activity against many tumor cell lines (IC(50) values of 10 nM or less).

Antineoplastic Agents↗
PubMed2004

Use of multiple antigenic peptides related to antigenic determinants of infectious bursal disease virus (IBDV) for detection of anti-IBDV-specific antibody in ELISA--quantitative comparison with native antigen for their use in serodiagnosis.

Multiple antigenic peptides (MAPs) prepared for the predicted antigenic determinants on the VP2 protein of infectious bursal disease virus (IBDV) were used as antigens in enzyme-linked immunosorbent assay (ELISA)--an alternative to whole viral antigen to detect anti-IBDV antibodies in the chicken sera. Two MAPs were synthesized, which could specifically detect the anti-IBDV antibodies in serum samples by ELISA. The optimum quantity of MAP1 and MAP2 required to coat the wells of the ELISA plate was 5 ng/ml, whereas the amount of purified IBDV whole viral antigen was 500 ng/ml, indicating the high efficiency of MAPs. In this study, we mainly focused on the antigenicity of two eight-branched MAPs to detect anti-IBDV antibodies in ELISA, which would serve as safe, chemically defined, noninfectious alternative antigens to whole virus in serodiagnosis. The specificity and sensitivity of both MAP1 and MAP2 were found to be relatively better than the whole viral antigen.

Animals↗
PubMed2004

Prevalence and distribution of peste des petits ruminants virus infection in small ruminants in India.

Peste des petits ruminants (PPR) is an acute febrile viral disease of goats and sheep characterised by mucopurulent nasal and ocular discharges, necrotising and erosive stomatitis, enteritis and pneumonia. The disease is endemic in India and causes large economic losses each year due to the high rates of mortality and morbidity in infected sheep and goats. The present study reports observations from 58 laboratory confirmed outbreaks of PPR and provides details of the prevalence of antibodies to PPR virus (PPRV) in 4,407 serum samples of small ruminants. Most of the clinical specimens used for the study originated from the northern and central parts of India. Serum samples used for the detection of antibodies to PPRV were derived from a greater number of regions within the country, however, these samples may not be a true representation of the target population (unvaccinated sheep and goats over 3 months old). Indigenously developed monoclonal antibody-based diagnostic kits were used for the detection of PPRV antigen (sandwich enzyme-linked immunosorbent assay [ELISA]) and antibody (competitive ELISA). Findings suggested that the disease outbreaks were more severe in goats than sheep and that the frequency of disease outbreaks was greater between the months of March and June (51.7%) as compared to other periods of the year. Based on the screening of the 4,407 sera samples, the antibody prevalence of PPRV in small ruminants in India was 33% (95% confidence interval: 32.3% to 33.7%). The prevalence of antibodies to PPRV was noted to differ between species (i.e. sheep versus goats), age groups and geographical regions. A greater proportion of the sheep (36.3%) versus the goat (32.4%) population was infected with PPRV. The distribution and prevalence of antibodies to PPRV among various age groups of animals indicated that goats were exposed at an earlier age than the sheep, suggesting that goats may be more susceptible to infection with PPRV. A greater number of positive cases were observed in the southern and southwestern part of the country (30%-60%) as compared to northern India (10%-30%). These findings may be correlated with variations in the sheep and goat husbandry practices within different geographic regions, the topography of different states and the socio-economic status of individual Indian farmers.

Age Factors↗
PubMed2004

Detection of Infectious bursal disease virus by ELISA using an antipeptide antibody raised against VP3 region.

Antigenic determinant analysis was carried out on VP3, one of major immunogenic proteins of Infectious bursal disease virus (IBDV) using computer algorithms. Altogether 17 peptides were synthesized for predicted putative regions and were tested for their reactivity with IBDV-positive polyclonal sera as well as with antisera to other common avian viruses to confirm specificity and to rule out cross reactivity. Of 17 peptides tested, three were selected and synthesized in multiple antigenic peptide (MAP) format. The immunization of rabbits with the three MAPs resulted in high humoral immune response. The purified antipeptide antibodies were screened against native IBDV antigen and the respective titers were determined. Out of the three antisera to MAPs that raised against the MAP3, spanning the amino acids (aa) 974-995 region on the VP3 protein had a very high titer (2048) and reacted specifically with IBDV. Thus, the antiserum to MAP3 detected native virus in enzyme-linked immunosorbent assay (ELISA), revealing the presence of a potential antigenic determinant on the C-terminus of the protein. This study proved that an antipeptide antibody could be used as a safe and specific tool for the diagnosis of IBD in chickens.

Animals↗
PubMed2004

Development of a N gene-based PCR-ELISA for detection of Peste-des-petits-ruminants virus in clinical samples.

A highly sensitive N gene-based PCR-ELISA for the detection of Peste-des-petits-ruminants virus (PPRV) was developed. The RT-PCR yielded a digoxigenin (DIG)-labeled product of 336 bp comprising a sequence from PPRV N gene, which was then detected by ELISA. The assay could detect the viral RNA in PPRV-infected tissue culture fluids with a titer as low as 0.1 TCID(50)/ml. The assay is 10,000 times more sensitive than a classical RT-PCR combined with agarose gel electrophoresis. The assay could detect the virus in the clinical samples, which were negative by conventional sandwich ELISA (S-ELISA). The percentage positivity of the assay in detecting the virus in clinical samples was 66.2% compared to 48.6% for S-ELISA. The assay was more sensitive than S-ELISA also in detecting the virus in early as well as late phases of the disease. In addition, the assay could also be used for differential diagnosis of PPRV and Rinderpest virus (RPV).

Animals↗
PubMed2003

A short, stereocontrolled, and practical synthesis of alpha-methylomuralide, a potent inhibitor of proteasome function.

An efficient and practical synthesis of alpha-methylomuralide (3), a selective inhibitor of proteasomes, has been developed as outlined in Scheme 1. Among the advantages of this route of synthesis over previously described approaches are (1) ease of scale-up and (2) high yields (28% overall yield of alpha-methylomuralide from 6) and stereocontrol (including high enantiocontrol). The synthesis is well suited to the production of 3 in the quantities needed for material-intensive in vivo investigations.

Catalysis↗
PubMed2002

Crystal structure of binary and ternary complexes of serine hydroxymethyltransferase from Bacillus stearothermophilus: insights into the catalytic mechanism.

Serine hydroxymethyltransferase (SHMT), a member of the alpha-class of pyridoxal phosphate-dependent enzymes, catalyzes the reversible conversion of serine to glycine and tetrahydrofolate to 5,10-methylene tetrahydrofolate. We present here the crystal structures of the native enzyme and its complexes with serine, glycine, glycine, and 5-formyl tetrahydrofolate (FTHF) from Bacillus stearothermophilus. The first structure of the serine-bound form of SHMT allows identification of residues involved in serine binding and catalysis. The SHMT-serine complex does not show any significant conformational change compared with the native enzyme, contrary to that expected for a conversion from an "open" to "closed" form of the enzyme. However, the ternary complex with FTHF and glycine shows the reported conformational changes. In contrast to the Escherichia coli enzyme, this complex shows asymmetric binding of the FTHF to the two monomers within the dimer in a way similar to the murine SHMT. Comparison of the ternary complex with the native enzyme reveals the structural basis for the conformational change and asymmetric binding of FTHF. The four structures presented here correspond to the various reaction intermediates of the catalytic pathway and provide evidence for a direct displacement mechanism for the hydroxymethyl transfer rather than a retroaldol cleavage.

Aldehydes↗
PubMed2002

Psychological well-being in patients on 'adequate' doses of l-thyroxine: results of a large, controlled community-based questionnaire study.

OBJECTIVE: Over 1% of the UK population is receiving thyroid hormone replacement with l-thyroxine (T4). However, many patients complain of persistent lethargy and related symptoms on T4 even with normal TSH levels. To date there has been no large study to determine whether this is related to thyroxine replacement or coincidental psychological morbidity. We have therefore attempted to address this issue using a large, community-based study. DESIGN AND PATIENTS: Computerized prescribing records of five general practices were used to identify 961 patients who had been on thyroxine for a minimum of 4 months from a population of 63 000 (1.5%), along with age- and sex-matched controls. All 1922 individuals were sent a two-page questionnaire, made up of the short form of the General Health Questionnaire (GHQ-12), designed to detect minor psychiatric disorders in the community, and a 12-question 'thyroid symptom questionnaire' (TSQ) in the same format. A covering letter explained that we were interested in 'how patients felt on medication' and made no direct reference to thyroxine. MEASUREMENTS: Scores from the GHQ and TSQ were marked for each individual using the GHQ and Likert scoring methods. Patients' latest TSH measurements were obtained from laboratory records. Comparisons were then made on scores for the total GHQ-12, TSQ and individual questions between patients (P) and control (C) groups. Separate analyses were made comparing the patients with a normal TSH (nP) and the control group. RESULTS: Five hundred and ninety-seven (62%) of the patients (P) and 551 (57%) of the controls (C) responded and fully completed at least one of the two questionnaire. Three hundred and ninety-seven responding patients (nP) had a TSH estimation performed in the previous 12 months with the last result being in the local laboratory normal range for TSH (0.1-5.5 or 0.2-6.0 mU/l, according to the assay method used). The responding P, nP and C populations were well matched for age (59.96, 59.73, 59.35 years) and sex (85%, 83%, 87% female). The number of individuals scoring 3 or more on the GHQ-12 (indicating 'caseness') was 21% higher in P than C [185/572 (32.3%) vs. 137/535 (25.6%), P = 0.014] and 26% higher in nP than C [131/381 (34.4%) vs. 137/535 (25.6%), P < 0.005]. Stronger differences were seen with the TSQ scores [C = 187/535 (35.0%), P = 273/583 (46.8%), P < 0.001, P vs. C; and nP = 189/381 (48.6%), P < 0.001, nP vs. C]. Differences existed in chronic drug use and chronic disease prevalence between the control and patient groups, but the differences in GHQ and TSQ scores between the groups remained significant even after correction for these factors as well as age and sex in multiple regression analysis. CONCLUSIONS: This community-based study is the first evidence to indicate that patients on thyroxine replacement even with a normal TSH display significant impairment in psychological well-being compared to controls of similar age and sex. In view of the large numbers of people on thyroxine replacement, we believe that these differences, although not large, could contribute to significant psychological morbidity in a substantial number of individuals.

Adolescent↗