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Biomedical subjects

S K Dutta

Publications and source records attributed to S K Dutta.

At least 19 recordsLinked to original sources
PubMed1992

Limbs generated at site of tail amputation in marbled balloon frog after vitamin A treatment.

Niazi and Saxena first observed that vitamin A has an inhibitory and modifying influence on tail regeneration in Bufo andersonii tadpoles. A positive relationship was later found between the inhibiting influence of vitamin A and the developmental stage of the regenerating tail in the same species. There have been several subsequent reports on the effects of vitamin A and its derivatives on limb development and regeneration. Thus in regenerating amphibian limbs, application of retinoids produces pattern duplication in the proximodistal and anteroposterior axes of the limb, and local application of retinoic acid to the anterior side of developing chick limbs causes duplications in the anteroposterior axis of limb. Here we show that vitamin A can cause limb development when applied to amputated tail stumps of the tadpoles of the marbled balloon frog Uperodon systoma (Anura Microhylidae). This is the first report of homeotic transformation mediated through vitamin A in vertebrates.

Amputation, Surgical↗
PubMed1992

Dose dependence of acetylcholinesterase activity in neuroblastoma cells exposed to modulated radio-frequency electromagnetic radiation.

Radio-frequency electromagnetic radiation (RFR) at 915 and 147 MHz, when sinusoidally amplitude modulated (AM) at 16 Hz, has been shown to enhance release of calcium ions from neuroblastoma cells in culture. The dose-response relation is unusual, consisting of two power-density "windows" in which enhanced efflux occurs, separated by power-density regions in which no effect is observed. To explore the physiological importance of these findings, we have examined the impact of RFR exposure on a membrane-bound enzyme, acetylcholinesterase (AChE), which is intimately involved with the acetylcholine (ACh) neurotransmitter system. Neuroblastoma cells (NG108), exposed for 30 min to 147-MHz radiation, AM at 16 Hz, demonstrated enhanced AChE activity, as assayed by a procedure using 14C-labeled ACh. Enhanced activity was observed within a time window between 7.0 and 7.5 h after the cells were plated and only when the exposure occurred at power densities identified in a previous report as being effective for altering the release of calcium ions. Thus RFR affects both calcium-ion release and AChE activity in nervous system-derived cells in culture in a common dose-dependent manner.

Acetylcholinesterase↗
PubMed1992

Modulation of salivary secretion by acid infusion in the distal esophagus in humans.

To examine the relationship between esophageal acid exposure and development of salivation and heartburn, 15 healthy subjects underwent perfusion of the distal esophagus with varying concentrations of hydrochloric acid, different-osmolality saline solutions, and deionized water. In five study subjects, hydrochloric acid was infused in the body of the stomach only. During the study, timed samples of whole and parotid saliva were collected and analyzed for flow rate and bicarbonate concentration. Only hydrochloric acid concentrations of 20 mmol/L or greater (pH 1.8 or lower) induced a rapid (within 2 minutes) and significant (P < 0.05) increase in salivation. The hydrochloric acid-induced salivation was associated with significant (P < 0.05) increase in bicarbonate secretion in both parotid and whole saliva samples. Intravenous atropine administration completely inhibited hydrochloric acid-induced salivary secretion in all six subjects. Changes in osmolality of saline solution infused in the esophagus and hydrochloric acid infused in the stomach did not significantly alter parotid and whole saliva flow rates. These data suggest that in humans, rapid salivation in response to esophageal mucosal exposure to intraluminal hydrochloric acid is a pH-dependent and osmolality-independent phenomenon that is most likely mediated by pH-sensitive chemoreceptors located in the esophageal mucosa.

Adult↗
PubMed1992

Campylobacter species as a cause of diarrhoea in children in Calcutta.

From 1985 to 1988, 857 children (aged between 1 day and 60 months) admitted to hospital with diarrhoea and 241 controls (aged between 5 days and 60 months) were examined for campylobacters and other enteric pathogens by means of conventional methods. The difference between the isolation rates of campylobacters in those cases in which no other enteric pathogen was found (4.8%) and controls (6.2%) was not significant (P greater than 0.05). Strains of Campylobacter jejuni/coli were isolated throughout the year with higher isolation rates during the summer and monsoon months. Mixed infections were very common. Watery diarrhoea (97.6% cases) was the most common clinical presentation of patients found to be infected solely by C. jejuni/coli. Most patients infected with campylobacters were mildly to moderately dehydrated. Biotype I of C. jejuni and C. coli was the dominant biotype associated with cases and controls. All strains of C. jejuni/coli, regardless of their source, were found to be sensitive to erythromycin. From this study, it appears that enteric infections with campylobacters among children in Calcutta are common but often asymptomatic.

Bacterial Typing Techniques↗
PubMed1992

Evaluation of vitamin A absorption by using oil-soluble and water-miscible vitamin A preparations in normal adults and in patients with gastrointestinal disease.

We evaluated vitamin A absorption in 50 healthy adults and 26 gastrointestinal-disease patients by measuring the postabsorptive response in plasma retinyl esters after oral doses of the vitamin. On 3 consecutive days, two physiologic-dose tests of 2000-2400 retinol equivalents (RE) and one pharmacologic-dose test (84,000 RE) were administered. The physiologic doses were given as an oil-soluble or a water-miscible preparation. In gastrointestinal-disease patients the physiologic-dose test was highly correlated with the pharmacologic-dose test for the oil-soluble preparation as determined by peak rise (r = 0.50, P less than 0.05) and area under the curve (r = 0.56, P less than 0.01), suggesting that the physiologic dose is valid for investigating vitamin A absorption. Intestinal-disease or resection patients absorbed preparations poorly. Pancreatic-disease patients absorbed the oil-soluble preparation poorly. Physiologic rather than pharmacologic doses of vitamin A can be used to study vitamin A absorption.

Absorption↗
PubMed1992

Antigenic and genomic relatedness among Ehrlichia risticii, Ehrlichia sennetsu, and Ehrlichia canis.

Antigenic and genomic relatedness among Ehrlichia risticii, E. sennetsu, and E. canis was analyzed by enzyme-linked immunosorbent assay, Western blotting (immunoblotting) and DNA-DNA hybridization. E. risticii and E. sennetsu were serologically related, and their Western blot antigen profiles were nearly identical. Two antigens of E. sennetsu corresponding to the 28- and 51-kDa antigens of E. risticii were apparently larger than the E. risticii antigens, and the 55-kDa antigen of E. risticii appeared to be unique to this species. The 110-, 70-, and 44-kDa antigens of these two species were identical, as determined by the use of monospecific antibodies. DNA homology between these two species was high. On the other hand, E. canis was antigenically least reactive with the antisera to E. risticii and E. sennetsu. However, a dog convalescent-stage E. canis antiserum recognized antigens in the other two species which were different from those recognized by their homologous antisera. Similarly, homology between the DNA of E. canis and the DNAs of the other two species was very minimal. These results indicate that E. risticii and E. sennetsu are closely related both at the genomic and antigenic levels and that the relationship of these two species with E. canis is minimal.

Antigens, Bacterial↗
PubMed1992

Identification of the protective 44-kilodalton recombinant antigen of Ehrlichia risticii.

Protective studies were conducted with mice by using recombinantly produced antigens, polyacrylamide gel electrophoresis-fractionated antigens, and a monoclonal antibody specific to the 28-kDa antigen of Ehrlichia risticii. Analysis of E. risticii-infected cell culture used as the challenge inoculum indicated an inverse relationship between the progression of cell culture infection and the infective capability of E. risticii for mice. A recombinant 44-kDa antigen was found to protect mice considerably against challenge infection, while the monoclonal antibody and fractionated antigens were not protective. A potentiation of protection was observed when the recombinant 44-kDa antigen was combined with the recombinant 70-kDa antigen and used for mouse immunization.

Animals↗
PubMed1992

Ethanol and human saliva: effect of chronic alcoholism on flow rate, composition, and epidermal growth factor.

Parotid saliva samples from 24 alcoholic subjects without evidence of cirrhosis were analyzed for changes in flow rate, composition, and epidermal growth factor (EGF) secretion. Mean (+/- SE) stimulated parotid saliva flow rate (ml/min/gland) was significantly (p less than 0.01) lower in alcoholic subjects than in matched control subjects. Reduction in parotid saliva flow rate was associated with significant (p less than 0.05) decrease in total protein and amylase secretion in this group of patients. In addition, secretion of immunoreactive EGF, a specific salivary protein, was also markedly reduced (p less than 0.05) in alcoholic patients. None of the parotid saliva samples from the alcoholic subjects had detectable bioactivity of EGF in saliva. These data suggest that chronic alcohol ingestion is associated with significant changes in parotid saliva secretion and its composition, which may perpetuate and compound ethanol-induced injury to the upper gastrointestinal tract.

Adult↗
PubMed1992

Diagnostic evaluation of ascitic adenosine deaminase activity in tubercular peritonitis.

Activity of adenosine deaminase (ADA) in serum and peritoneal fluid was studied prospectively in 24 aetiologically proved cases of ascites and 10 age-matched controls. Patients were divided into 3 groups according to causes of ascites, viz. malignant ascites (11), tubercular peritonitis (7) and cirrhosis of liver (6). Serum ADA values and peritoneal: serum ADA ratio did not show any consistent pattern in any group. But in patients with tubercular peritonitis ADA activity in ascitic fluid was significantly higher (P < .001) than in the other groups. An ascitic ADA level of 30 units/L had a sensitivity of 100% and specificity of 94.1% for tubercular peritonitis. These findings suggest that the ascitic fluid ADA activity is useful for the diagnosis of tubercular peritonitis; this method is simple and least invasive.

Adenosine Deaminase↗
PubMed1992

Bacteriology of wound infection: evaluation by surface swab and quantitative full thickness wound biopsy culture.

A total of 171 cases of wounds of various aetiology were examined and screened bacteriologically for evidence of infection by surface swab culture and quantitative full thickness wound biopsy culture techniques. Staphylococcus pyogenes was the most frequently isolated (39.9%) single organism. Other organisms being Escherichia coli (26.1%), Pseudomonas aeruginosa (15.4%), klebsiella species (5.8%), Streptococcus pyogenes (4.9%), proteus species (4.8%) and coliform organism (3.1%). Collectively the Gram-negative organisms were the majority among the isolated organisms. As indicator of wound infection, surface swab culture was found to be reliable in 72% cases when correlated with wound biopsy culture. The latter technique was found to be more consistently valuable (in 95% cases) both for regular assessment of the wounds as well as to judge the response to treatment.

Bacterial Infections↗
PubMed1991

Inhibition of respiration of tumor cells by methylglyoxal and protection of inhibition by lactaldehyde.

The effect of methylglyoxal (MG), ascorbic acid and lactaldehyde has been tested on the in vitro respiration of Ehrlich ascites carcinoma (EAC) cells and several normal and malignant human tissues. Methylglyoxal inhibited the respiration of each type of malignant cell and tissue tested, but it had practically no inhibitory effect on the respiration of any of the normal cells and tissues. Ascorbic acid exhibited a synergistic effect with MG in inhibiting the respiration of all the neoplastic cells. In the presence of lactaldehyde, a catabolite of MG, the inhibitory effect of MG on the respiration of tumor cells was significantly reduced. Lactaldehyde can exert a similar protective effect on the loss of viability and transplantability of MG-treated EAC cells.

Aldehydes↗
PubMed1991

Pancreatic enlargement in alcoholic pancreatitis: prevalence and natural history.

We determined the prevalence and natural history of pancreatic enlargement by abdominal ultrasonography or computed tomography in 72 patients with alcoholic pancreatitis. Pancreatic enlargement was observed in 54 patients (75%); it was diffuse in 28 (52%) and focal in 26 (48%). The focal enlargement was frequently cystic (50%), while the diffuse enlargement was only occasionally cystic (7%). Sequential imaging of the pancreas in 29 patients demonstrated partial to total resolution of pancreatic enlargement in greater than 50% during 6 months of follow-up. Determination of serum amylase and p-isoamylase activity was neither sensitive nor specific for pancreatic enlargement in alcoholic pancreatitis.

Acute Disease↗
PubMed1991

Extraction and purification of curcain, a protease from the latex of Jatropha curcas Linn.

A proteolytic enzyme, curcain, has been extracted from the latex of Jatropha curcas Linn. The enzyme was purified by chromatography on carboxymethyl cellulose and gel filtration on Sephadex G-200. The homogeneity of protein associated with curcain was established by non-denatured polyacrylamide gel electrophoresis using a discontinuous buffer system. The molecular weight of curcain was estimated by Sephadex G-100 gel filtration using a calibration curve of standard proteins to be around 22,000 daltons.

Chromatography, Gel↗
PubMed1991

Molecular cloning and analysis of recombinant major antigens of Ehrlichia risticii.

The genome of Ehrlichia risticii, the etiologic agent of Potomac horse fever, was cloned in the lambda gt11 expression vector. The efficiency of recombinant phage production with different restriction fragments of E. risticii DNA was generally between 20 and 95%. The antigen-positive frequency, detected by immunoscreening with E. risticii antibodies, was between 8 and 40 per 10(4) recombinants. Four (70, 55, 51, and 44 kDa) major antigens of E. risticii were identified from the recombinant phages by using recombinant antigen-selected monospecific antibodies. Characterization of three (70, 55, and 44 kDa) of these recombinant antigens indicated that the 70- and 44-kDa polypeptides were beta-galactosidase fusion products that were dependent on isopropylthiogalactoside induction for expression; they contained about 50 and 73%, respectively, of the native polypeptides. The 55-kDa antigen was a nonfusion protein expressed independently of isopropylthiogalactoside induction; it was a complete protein with a molecular weight identical to that of its native counterpart. The cloned E. risticii DNAs from of the recombinants expressing 70-, 55-, and 44-kDa proteins were 3.5, 3.9, and 4.8 kb, respectively, in size, and they were unique. The insert DNAs hybridized to multiple restriction fragments of the genomic DNA, the sum of the sizes of which was much greater than that of the corresponding insert. Mice immunized with the affinity-purified 55-kDa recombinant antigen produced a high titer of antibody in serum as measured by an enzyme-linked immunosorbent assay and gave a monospecific reaction by Western immunoblotting. Challenge infection of these immunized mice showed low protection from clinical infection.

Animals↗
PubMed1991

Diagnostic application of polymerase chain reaction for detection of Ehrlichia risticii in equine monocytic ehrlichiosis (Potomac horse fever).

Genomic amplification by the polymerase chain reaction (PCR) was used to identify a unique genomic sequence of Ehrlichia risticii directly in DNA isolated from peripheral-blood buffy coat cells of E. risticii-infected horses (Potomac horse fever) and from infected cell cultures. A specific primer pair, selected from a cloned, species-specific, 1-kb DNA fragment of the E. risticii genome as a template, was used for the amplification of the target DNA of 247 bp. The optimal number of 40 PCR cycles, determined by analyzing an amplification profile obtained with a constant Taq polymerase concentration, was used to achieve maximum amplification of the E. risticii DNA segment. Efficient amplification of target DNA was achieved with specimens processed by either the phenol extraction or rapid lysis method. The specificity of the amplified DNA product was confirmed by the proper size (247 bp) and appropriate restriction enzyme cleavage pattern of the amplified target DNA, as well as by the specific hybridization signal obtained by using a PCR-amplified 185-bp internal DNA probe. A 10(5)- to 10(6)-fold amplification of target DNA, which allowed detection of E. risticii from as few as two to three infected cells in culture and from a very small volume of buffy coat cells from infected horses, was achieved. This PCR amplification procedure was found to be highly specific and sensitive for the detection of E. risticii for the study of Potomac horse fever.

Animals↗
PubMed1991

Study of cell mediated immunity in chronic tonsillitis.

The cell mediated immune status (CMI) of twenty three patients with chronic tonsillitis was studied with a view to ascertain any possible role of CMI deficiency in causation of the disease. No evidence of significant CMI deficiency was detected in these cases.

Chronic Disease↗