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Biomedical subjects

S Srinivasan

Publications and source records attributed to S Srinivasan.

At least 217 records · Page 12Linked to original sources
PubMed1992

Multidrug resistant enteric fever.

Multidrug resistant typhoid fever (MDRT) is becoming an alarming public health problem in and around Pondicherry, South India. A retrospective review of the multidrug resistant typhoid fever cases admitted to the paediatrics ward of JIPMER Hospital, Pondicherry (India) during 1990 is presented. Prolonged pyrexia, chills and rigors, toxaemia, and tender hepatomegaly often more than 3 cm below the costal margin (often without splenomegaly) were striking features of MDRT cases. The incidence of complications was also greater. Positive blood cultures were observed even after weeks of antibiotic therapy, indicating persistent bacteraemia; resistance was almost always observed for multiple drugs (two or more). The fluoroquinolone group of drugs such as ciprofloxacin have been found to be the best for MDRT in terms of rapid response and cost effectiveness. Cefotaxime has moderate efficacy.

Anti-Bacterial Agents↗
PubMed1991

Experimental and theoretical studies of the three-dimensional structure of human interleukin-4.

The structure of human interleukin 4 (IL-4) was predicted utilizing a series of experimental and theoretical techniques. Circular Dichroism (CD) spectroscopy indicated that IL-4 belonged to the all alpha-helix class of protein structures. Secondary structure prediction, site-directed mutagenesis, and CD spectroscopy suggested a predominantly alpha-helical structure, consistent with a four-helix bundle structural motif. A human/mouse IL-4 chimera was constructed to qualitatively evaluate alternative secondary structure predictions. The four predicted helices were assembled into tertiary structures using established algorithms. The mapping of three disulfide bridges in IL-4 provided additional constraints on possible tertiary structures. Using accessible surface contact area as a criterion, the most suitable structures were right handed all antiparallel four-helix bundles with two overhand loop connections. Successful loop closure and incorporation of the three disulfide constraints were possible while maintaining the expected shape, solvent accessibility, and steric interactions between loops and helices. Lastly, energy minimization was used to regularize the chain.

Amino Acid Sequence↗
PubMed1991

A profile of pyogenic meningitis in children.

Clinical profile of pyogenic meningitis was studied in 256 cases over a period of 8 years. The male to female ratio was 1.46: 1 and 83.6% of the patients were less than 3 years of age. Fever, altered sensorium, refusal to feed, convulsions and vomiting were the common presenting symptoms. Six (2.3%) of them had subnormal temperature and the sensorium was normal in 12.5% of cases. Cerebrospinal fluid was clear in 9.4%, cell count was less than 100/cmm in 8.2%, sugar was more than 40 mg% in 24.2% and protein was less than 50 mg% in 12.5% of cases. Diplococcus pneumoniae was the commonest causative agent. The overall mortality was 30.5%. It is concluded that young children suffering from this disease may not have the typical features and one should have the highest suspicion to make an early diagnosis so that the morbidity and mortality from this condition can be reduced.

Child, Preschool↗
PubMed1991

Serum malate dehydrogenase (MDH) in portal hypertension--its value as a diagnostic and prognostic indicator.

Serum MDH levels were estimated in 29 consecutive patients of portal hypertension with the objective of ascertaining its diagnostic value as to the cause of portal hypertension and its prognostic significance. Higher levels of serum MDH were found in cirrhotic patients as compared to noncirrhotic ones. There were however no significant differences found in the values when extrahepatic obstruction group was compared with controls. Furthermore, higher MDH activity was found in those patients who died as compared to the surviving ones.

Humans↗
PubMed1990

Automated access to a large medical dictionary: online assistance for research and application in natural language processing.

Online dictionaries can be important tools for research and application in natural language processing. This paper describes work with a machine-readable version of "Dorland's Illustrated Medical Dictionary". First the characteristics of the dictionary are briefly described, and then the complex process of converting the tape to an online interactive dictionary is discussed. The results of several experiments in automatically deriving information from the online dictionary are presented, and the paper ends with a discussion of the use of the online dictionary as a tool in the development of a natural language processing system designed for the biomedical domain.

Abstracting and Indexing↗
PubMed1990

Establishing reliability of biomechanical data using univariate and multivariate approaches.

The purpose of this study was to use generalizability theory with both univariate and multivariate approaches to examine reliability of total body center of mass (CM) values calculated from cinematographical data. Twenty-eight college-aged male volunteers were filmed by a LOCAM camera at 100 fps while performing the basic locomotion skill of walking. Film analysis was conducted on each subject using six frames of film depicting a one-stride walking cycle consisting of right heel strike, right foot flat, left toe-off, left heel strike, left foot flat, and right toe-off. Nineteen segmental endpoints and a reference point were digitized by three experienced plotters. The digitizing sequence was replicated three times by each plotter. A FORTRAN program calculated nine CM values (three plotters by three repetitions) for each subject filmed in each of the six positions of the stride. The x- and y-coordinates of the CM values were the dependent variables analyzed by fully crossed 3-way univariate and multivariate ANOVAs (subjects by plotters by repetitions). All measurement facets were considered to be random. Results indicate that there was very little repetition error but considerable interplotter error for most frames. Phi-coefficients for x- and y-coordinates, separately, fluctuated across frames. The univariate values for the x-coordinates were similar but slightly less than the multivariate values. The Phi-coefficients for Y, however, were considerably lower than the multivariate values. The multivariate Phi-coefficients for generalizing over three plotters and three repetitions ranged from .82 to .90.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Formation of 5-hydroxymethyl-2'-deoxyuridine in hepatic DNA of rats treated with gamma-irradiation, diethylnitrosamine, 2-acetylaminofluorene or the peroxisome proliferator ciprofibrate.

The peroxisome proliferator ciprofibrate was tested for its ability to induce DNA damage in the form of 5-hydroxymethyl-2'-deoxyuridine (HMdU), an adduct that results from the reaction of thymine in DNA with hydroxyl radicals. In order to quantify HMdU, DNA containing [3H]thymidine of high specific activity had to be obtained. Since hepatocytes normally have a very low rate of DNA synthesis, rats were subjected to partial hepatectomy to stimulate DNA synthesis and then were administered [methyl-3H]thymidine by three p.o., i.p. or i.v. injections 20, 22 and 24 h after partial hepatectomy; or by slow infusion through the portal vein, starting 20 h after partial hepatectomy for 4 h. The specific activity of DNA in rats receiving [3H]thymidine through the portal vein was considerably higher than in rats receiving p.o., i.p. or i.v. injections. Rats were then exposed to various doses of gamma-irradiation after partial hepatectomy and infusion of [6-3H]thymidine through the portal vein. DNA from the liver was extracted, enzymatically hydrolyzed and analyzed by HPLC. The percentage of HMdU in DNA increased in a dose-dependent manner. Rats were then treated with the carcinogens 2-acetylaminofluorene (AAF) or diethylnitrosamine (DEN) in conjunction with partial hepatectomy and infusion of [methyl-3H]thymidine. There was an increase in HMdU formation after a single administration of DEN or AAF. Another group of rats was fed a diet containing the peroxisome proliferator ciprofibrate for 3 weeks. After partial hepatectomy and infusion of [6-3H]thymidine, these rats were fed the same ciprofibrate-containing diet for 2-4 more weeks. HMdU was detected in DNA at 2-4 weeks after [6-3H]thymidine infusion, but the level at 4 weeks was nearly 50% less than at 2 weeks. This study shows that oxidative DNA damage in the form of HMdU is induced in the liver by gamma-irradiation, DEN, AAF and peroxisome proliferation.

2-Acetylaminofluorene↗
PubMed1990

Empyema in infancy and childhood.

A study of 108 cases of empyema during 18 months period showed the incidence of empyema to be 2.17%. Staph. aureus (17.6%) was the common causative organism. Response to a combination of cloxacillin and gentamicin was better than that of crystalline penicillin and gentamicin. Only 30.3% cases needed intercostal drainage for more than 2 weeks. Almost 43% cases could be discharged by 3-4 weeks after hospitalisation and 38.1% by 30-57 days. The mortality rate was 12.1%. Among the survivors, excluding 8 children who left against medical advice, all had complete recovery excepting one child in whom AFB was isolated and who developed bronchiectasis and recurrent hemoptysis, inspite of antituberculous treatment. Age of the child, antibiotic combination given and nutritional status appear to be the main factors influencing the recovery and prognosis.

Anti-Bacterial Agents↗
PubMed1990

Typhoid fever below five years.

During a seven year period (1981-87), 53 cases of typhoid fever in children below five years were seen. This accounted for 13.5% of all typhoid admission in pediatrics during the above period. Predominant symptoms were fever (100%), vomiting (52.8%), diarrhea (30.2%) and anorexia (24.5%). Chills and rigor associated with fever was noticed in 38% of the children. Salmonella typhi was isolated from blood in 22 of 53 (41.7%) cases. A significant finding on peripheral smear was eosinopenia (86.8%). Complications like endotoxic shock, enteric encephalopathy and gastrointestinal hemorrhage were noticed in only few cases (7.6%). There were no deaths.

Child, Preschool↗
PubMed1989

Revised immune network concepts.

The idiotype network concept needs to be revised in order to be in agreement with current data on protein/protein interactions, with the phenomenon of T and B cell recognition of idiotopes, and with the failure of certain anti-idiotypes to stimulate a given immune response. It is proposed that the distinction among Ab2 alpha, beta, and gamma is abandoned, as well as the concept of an internal image idiotope which mimics the three-dimensional shape of nominal antigen. In place of these definitions, the concept of "network antigen" is introduced. Network antigens are potentially the entire repertoire of anti-idiotypes. However, their biological effectiveness is controlled and established by two factors: (i) the affinity to the idiotype Ig receptor; and (ii) the preexisting regulatory network segment that controls the outcome of immune stimulation or suppression. Screening for effective idiotype therapeutic agents has to be done with panels of anti-idiotype and idiotype antibodies in order to establish correlations between idiotope expression and disease progression. Recognizing the importance of network segments will be the first step in the direction toward a rational design of idiotype-based therapies.

Humans↗
PubMed1989

Poliomyelitis: 20 years--the Pondicherry experience.

During a 20-year period, 12,830 cases of acute poliomyelitis in children (aged 1 month-12 years) were seen in a South Indian teaching hospital (Pondicherry). Almost three-quarters (72.4%) of children were below the age of 2 years. The median age at onset of poliomyelitis shifted from 19.5 months (in the period 1968-1977) to 11 months (in the years 1978-1987). After 1981, epidemic peaks were noted every third year. 66.3% of cases had not received even a single dose of oral polio vaccine and 14.7% cases were vaccine failures (in the years 1983-1987). Provocation of poliomyelitis occurred in 66% of children and usually followed intragluteal injections associated with treatment of non-specific fevers. The overall mortality was 2.13%, the major cause of death being respiratory failure (60%). Polio virus type 1 was the major isolate among selected cases studied during 1983-1987. The risk factors identified in our study are lack of immunization and administration of intramuscular injections during the pre-paralytic phase. Ensuring early administration of multiple doses of oral polio vaccine to infants and avoiding intramuscular injections in young febrile children are important measures for the control of poliomyelitis--a continuing problem in Southern India.

Age Factors↗