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Biomedical subjects

V R Srinivasan

Publications and source records attributed to V R Srinivasan.

At least 19 recordsLinked to original sources
PubMed2005

Lymph node infarction--a rare complication associated with disseminated intra vascular coagulation in a case of dengue fever.

BACKGROUND: Lymph node infarction is known to occur in association with many non-neoplastic and neoplastic conditions however its occurrence in association with DIC is not reported hitherto in the literature. CASE PRESENTATION: We describe an unusual case of lymph node infarction in a twenty seven year old male following disseminated intravascular coagulation (DIC) in a case of dengue fever. Multiple sections of the infarcted and the surrounding non-infarcted lymph nodes failed to reveal any predisposing condition. How ever the parahilar vessels showed thrombotic occlusion, which must have been responsible for the infarction. CONCLUSION: Global infarction of the lymph node may mask the underlying pathology. Any malignancy especially lymphoma may coexist or follow lymph node infarction, therefore the patient needs constant surveillance.

Journal Article↗
PubMed2004

Myringoplasty using a subcutaneous soft tissue graft.

A retrospective study was performed on patients who underwent myringoplasty using an autologous subcutaneous soft tissue graft over a 5-year period. Details including age, site and size of perforation, grade of surgeon, surgical approach, postoperative dressings, overnight stay, complications and outcome were recorded and analysed. Fifty-two patients underwent myringoplasty using a subcutaneous soft tissue graft. Their ages ranged from 4 to 78 years (median = 36 years). The mean follow-up period was 19 months. Successful closure to give an intact tympanic membrane was obtained in 82.7% of patients. Thresholds improved on pure tone audiometry in 57.1% and deteriorated in only one patient. There was no case of dead ear as a result of surgery. Subcutaneous tissue graft has comparable outcomes with temporalis fascia graft with additional advantages of a smaller incision, minimum dissection and a lower risk of bleeding.

Adolescent↗
PubMed2003

Day-case myringoplasty: five years' experience.

A retrospective study of patients who underwent myringoplasty as a day-case procedure in two freestanding day-surgery units during a five-year period was carried out. Their case notes were identified and details including age, site and size of perforation, grade of surgeon, surgical approach, graft material, post-operative dressings, overnight stay, complications, and outcome were noted and analysed. The total number of patients including both children and adults who had myringoplasty as a day case was 144. Of these, 125 patients with 143 procedures were included in this study. Their ages ranged from four to 74 years (mean = 31 years). The perforation size was small in 40 cases, medium in 61 cases, and large/subtotal in 42 cases. The overnight stay rate was 2.7 per cent and this was for immediate post-operative problems such as nausea and bleeding from the wound. The readmission rate for post-operative complications was 2.1 per cent. The follow-up ranged from six months to five years (mean = 19 months). The success rate was 83.3 per cent and thresholds on pure tone audiometry improved in 69.2 per cent of cases. The age of the patient, grade of the surgeon, and graft material did not influence the surgical outcome. There was no case of dead ear as a result of surgery. Myringoplasty can be safely performed in both adults and children as a day-case procedure with low overnight stay and readmission rates. Success rates are comparable to when the procedure is performed on an in-patient basis.

Adolescent↗
PubMed2002

Myelopathy during treatment of autoimmune hemolytic anaemia.

A specific neurological syndrome resembling, subacute combined degeneration of spinal cord, has been observed to occur during treatment of autoimmune hemolytic anaemia (AHA). We propose that folate administration can precipitate this neurological syndrome in patients with subclinical deficiency of vitamin B12, a phenomenon more likely to occur in tropical countries. Such cases have not been previously reported.

Adult↗
PubMed2000

Clinical profile of falciparum malaria in a tertiary care hospital.

Falciparum malaria presents with protean manifestations and is associated with a variety of complications and has a high mortality. One hundred and fifty-eight consecutive cases of falciparum malaria were studied with respect to the clinical presentation, complications, and response to treatment. The mean age of patients was 38.60 +/- 15.45 years and majority of them were males i.e., males being 110 (69.62%) and females being 48 (30.37%). The commonest presenting manifestations were fever with chill and rigor (98.10%), altered sensorium (48.10%), algid malaria (18.35%), and jaundice (27.21%). The other presenting features being oliguria (6.96%) and bleeding manifestations due to disseminated intravascular coagulation (DIC) (4.43%). The frequently encountered complications were anaemia (74.68%), jaundice (40.50%), cerebral malaria (45.56%), thrombocytopenia (40.50%) and renal failure (24.68%). Most of the patients i.e., 126 (79.74%) recovered with treatment and 32 (20.25%) succumbed. Higher mortality was associated with higher parasite count, presence of complications like anaemia, jaundice, renal failure, DIC, adult respiratory distress syndrome (ARDS), and septicaemia. Most of the deaths were encountered in patients where there was delay in clinical diagnosis, in the pre-hospital phase, and consequent presentation in multiorgan failure. Early diagnosis and institution of specific therapy were rewarding in the remaining patients in this series.

Adult↗
PubMed1999

Malignancy in rheumatoid arthritis--a report of two cases.

The development of malignancy in the setting of pre-existing connective tissue disease is well known. We report two cases of rheumatoid arthritis who developed malignancy--multiple myeloma in one of them and carcinoma cervix in the other. Case 1 was a 62 year old man, who developed multiple myeloma three years after the onset of rheumatoid arthritis. Case 2 was a 61 year old female with history of rheumatoid arthritis for two years and who developed carcinoma cervix.

Arthritis, Rheumatoid↗
PubMed1990

Expression of an Erwinia sp. gene encoding diphenyl ether cleavage in Escherichia coli and an isolated Acinetobacter strain PE7.

An Acinetobacter strain PE7 with the ability to grow on salicyclic acid and to degrade diphenyl ethers was isolated from a petroleum waste pit in Louisiana. A cloned Erwinia sp. dpe gene encoding diphenyl ether cleavage was introduced into PE7 in order to enhance its degradative ability. A broad-host-range expression plasmid, pDPE2388, was constructed by inserting an SspI-HpaI fragment from a dpe gene-containing plasmid, pDPE7321, into the kanamycin resistance gene of plasmid pKT230. The DNA fragment contained the dpe gene flanked between sp6 and T7 promoters. Transconjugants of pDPE2388 plasmid into PE7 were isolated. Expression of the dpe gene in Escherichia coli or PE7 displayed a degradative ability to cleave the following diphenyl ethers: 4-chlorodiphenyl ether, 4-nitrodiphenyl ether, and 4-hydroxydiphenyl ether.

Acinetobacter↗
PubMed1989

Molecular cloning and expression of an Erwinia sp. gene encoding diphenyl ether cleavage in Escherichia coli.

A 2.1-kilobase fragment obtained by restriction enzyme HindIII digestion of Erwinia sp. genomic DNA was cloned into plasmid pUC19 and introduced into Escherichia coli by transformation. The transformants with diphenyl ether cleaving activity (Dpe+) were selected on agar plates with a specially designed medium (LTFN) containing 4-nitrodiphenyl ether. The positive clones showed a clear zone around the colonies. Analysis of mutants obtained by transposon mini-Mu dI(lacZ Kmr) mutagenesis indicated the coding region of the gene (dpe) and the utilization of a lacZ promoter of pUC19 for transcription of dpe. Clones with dpe in the opposite orientation in pUC19 were not expressed, confirming the need for a lacZ promoter. Utilization of a lacZ promoter in pUC19 was further confirmed by the observation that the degradation of 4-nitrodiphenyl ether was enhanced in the presence of isopropyl-beta-D-thiogalactoside. Expression of dpe was also found in pDPE7321, generated from cloning this gene into another plasmid, pSP73. Analysis of the plasmid-encoded proteins by the maxicell technique showed a polypeptide of 21,000 molecular weight as the product of dpe.

Bacterial Proteins↗
PubMed1979

Macromolecular composition of a Cellulomonas sp. cultivated in continuous culture under glucose and zinc limitation.

The mutant strain of Cellulomonas sp. (ATCC 21399) was cultivated under glucose and zinc limitation at a variety of growth rates in continuous culture. The growth characteristics and macromolecular composition of the population varied with the limitation imposed and the growth rate. Glucose- and zinc-limited cultures maintained a constant relative protein content. The relative ribonucleic acid content increased, whereas the carbohydrate and deoxyribonucleic acid contents decreased with an increase in the population growth rate in glucose-limited cultures. Free unbound lipid remained constant. The maximum population growth rate in zinc-limited cultures was directly proportional to the zinc concentration and demonstrated a traditional steady-state function. The nucleic acid content increased with increased growth rate; however, the relative nucleic acid content was significantly depressed when compared to glucose limited cells. This manner of cultivation may prove to be a useful tool for the production of single cell protein with lowered nucleic acid content and the elucidation of micronutrient involvement in growth-related processes.

Actinomycetales↗
PubMed1979

Continuous Cultivation for Apparent Optimization of Defined Media for Cellulomonas sp. and Bacillus cereus.

Steady-state continuous culture was used to optimize lean chemically defined media for a Cellulomonas sp. and Bacillus cereus strain T. Both organisms were extremely sensitive to variations in trace-metal concentrations. However, medium optimization by this technique proved rapid, and multifactor screening was easily conducted by using a minimum of instrumentation. The optimized media supported critical dilution rates of 0.571 and 0.467 h for Cellulomonas and Bacillus, respectively. These values approximated maximum growth rate values observed in batch culture.

Journal Article↗
PubMed1978

Affinity chromatographic purification of beta-glucosidase of Candida gulliermondii.

A beta-glucosidase was isolated from Candida guilliermondii, a yeast capable of growth on cellobiose. The enzyme was partially purified by treatment with polyethyleneimine and ammonium sulfate precipitation. Further purification was achieved by affinity chromatography using a Sepharose 4B matrix to which oxidized salicin was coupled through adipic dihydrazide. The final product was a 12.5-fold purification of the crude extract with a recovery of 27% of the initial enzyme activity. Polyacrylamide disc electrophoresis of the purified enzyme gave a single band. A km of 1.25 x 10(-4)M was obtained using p-nitrophenyl beta-D-glucopyranoside as the substrate. The optimum pH for enzyme activity was 6.8. Maximum activity was observed at temperature of 37 degrees C. Enzyme activity was completely inhibited by Hg++, Pb++, and Zn++ ions. The molecular weight of the enzyme is 48,000 as estimated by sucrose density gradient centrifugation.

Candida↗
PubMed1970

Tryptophan catabolism during sporulation in Bacillus cereus.

1. Two intermediates of tryptophan catabolism were isolated from a sporulating culture of Bacillus cereus and identified as anthranilic acid and kynurenine by their spectral properties. 2. During sporulation the rate of formation of anthranilic acid and kynurenine by whole cells increased and reached a maximum at the pre-spore stage. 3. The specific activities of tryptophan pyrrolase and formylase also increased during sporulation and exhibited a maximal activity at the pre-spore stage. 4. Kynureninase activity reached a maximum during early stages of sporulation and then started to decline. 5. There was a net increase in the activity of tryptophan pyrrolase when cells were grown in the presence of l-tryptophan or dl-kynurenine. 6. The cultures exhibited the maximal activity of kynureninase 2h earlier in the presence of dl-kynurenine whereas l-tryptophan delayed the appearance of the maximal activity by 2h. 7. The omission of glucose from the medium had no effect on the pattern of development of tryptophan pyrrolase during growth and sporulation. 8. On the addition of tryptophan to a chemically defined medium no significant change in the pattern of development of tryptophan pyrrolase was observed.

Bacillus cereus↗