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Biomedical subjects

R K Roy

Publications and source records attributed to R K Roy.

At least 19 recordsLinked to original sources
PubMed2004

Metabolic and stress responses of the body to trauma: produced by the laparoscopic and open cholecystectomy.

Laparoscopic cholecystectomy is regarded as gold standard therapy for symptomatic gall stone disease. This study was done to compare the metabolic and stress responses between open and lapraroscopic cholecystectomy and to evaluate their significance in postoperative recovery. Thirty patients with symptomatic gall stone disease were treated with open and laparoscopic cholecystectomy on elective basis (14 versus 16). Three samples of blood were collected from each patient to investigate serum cortisol, adrenaline, nor-adrenaline, C-reactive protein and blood glucose level. The mean age of patients was 41.86+/-10.13 blood glucose and stress hormones (cortisol, adrenaline, nor adrenaline) and C-reactive protein all were found significantly raised in the postoperative period in open cholecystectomy than laparoscopic cholecystectomy group. The postoperative recovery was also prolonged in the open group. The obvious clinical advantages of laparoscopic cholecystectomy over open cholecystectomy is mainly because of less metabolic and stress response.

Adult↗
PubMed1998

Do the diminishing efficacy and increasing toxicity of sodium stibogluconate in the treatment of visceral leishmaniasis in Bihar, India, justify its continued use as a first-line drug? An observational study of 80 cases.

Eighty parasitologically confirmed cases of visceral leishmaniasis (kala-azar) in Bihar, India, were treated daily with 20 mg sodium stibogluconate/kg for 30 days, to assess the current efficacy and toxicity of this 30-day regimen. Clinical and parasitological cure was obtained in 48 (60%) of the patients. However, 26 (33%) patients did not respond to the first course of treatment (primary unresponsiveness), two relapsed after initial clinical and parasitological cure, and two were withdrawn from the study (one on day 6 of treatment because of cardiotoxicity in the form of supraventricular tachycardia and the other on day 24 because of severe loss of appetite). All 30 patients who were not entirely cured with sodium stibogluconate were successfully treated with amphotericin B. Electrocardiographic changes occurred in many of the patients as the result of treatment with sodium stibogluconate. Diminution in the height of the T wave was seen in 32 (40%), inversion of the T wave (Minnesota code 5-1, 5-2) in seven (9%), elevation of the ST segment (Minnesota code 4-1) in three (4%), prolonged QT interval (compared with baseline findings) in six (8%), and diminution in the height of the P, R and T waves in two (3%). Cardiac arrhythmia occurred in five patients (6%), supraventricular arrhythmia (coarse atrial fibrillation) occurred in one patient and ventricular tachycardia, ventricular fibrillation, torsade de pointes and multifocal ventricular ectopics occurred in the four patients (5%) who died of cardiotoxicity. Minor side-effects, such as pain at the site of injection (two cases), mild diminution in appetite (12 cases), metallic taste in mouth (six cases), and joint pain (two cases), were also observed. It was concluded that the efficacy of sodium stibogluconate in the study area has declined over the years and that its toxicity has increased. A more efficacious, safer and cheaper, alternative drug is required as the first line of treatment of kala-azar.

Adolescent↗
PubMed1997

Detection of virulent Shigella and enteroinvasive Escherichia coli by induction of the 43 kDa invasion plasmid antigen, ipaC.

The invasion plasmid antigen, ipaC (43 kDa) of Shigella spp. and enteroinvasive Escherichia coli (EIEC) could be induced in vitro by growing them in the presence of Congo red. An enzyme-linked immunosorbent assay (ELISA) using antibodies to the 43 kDa protein of Shigella has been developed for specific detection of virulent Shigella spp and EIEC. The test is independent of initial isolation of individual colonies. As few as 10(2) CFU/ml of virulent Shigella present in mixed cultures could be detected and concurrently their susceptibility to antibiotics could be analysed after an initial growth of 8-16 h in Congo red-containing medium. The test may prove useful in the diagnosis and treatment of bacillary dysentery caused either by Shigella or EIEC through their rapid identification and proper antimicrobial therapy.

Antigens, Bacterial↗
PubMed1995

Construction of a cloning vector from a naturally occurring plasmid of Salmonella typhimurium.

A naturally occurring plasmid isolated from a drug-resistant strain of Salmonella typhimurium (993) has been used to construct a plasmid vector for cloning in a wild strain of Salmonella. The strain (993) contains at least two plasmids. The smaller plasmid (9 kb) contains an ampicillin-resistant marker, while the larger one (25 kb) is cryptic. Physical mapping of the 9-kb plasmid and construction of a 3.5-kb derivative have been carried out. This plasmid has been used for cloning in a restriction+modification+strain of S. typhimurium using a conventional calcium chloride method. It exhibited better efficiency of transformation than other commonly used plasmids such as pBR322 or its derivatives and transformants were found to be stable in the absence of antibiotic selection. The vector is compatible with pBR322 and can be used to study the expression of cloned genes in minicells.

Ampicillin Resistance↗
PubMed1992

Neurophysiological alterations following fluvalinate administration in mice.

Median lethal dose (LD50) of fluvalinate (Marvik 25EC) was 105 (94.6-116.5 mg/kg, ip) in albino mice. Gross observable signs were dose dependent and indicative of central and peripheral nervous system stimulation. Fluvalinate, at 10.5 and 21.0 mg/kg, ip doses in mice, facilitated maximal electroshock seizures, reduced reaction time in analgesic test and enhanced duration of ether anaesthesia. Acute and subacute (7 days) treatment at lower and higher doses enhanced pentobarbitone sleeping time. Acute and subacute treatment (7 days) with phenobarbitone (50 mg/kg, ip) prior to fluvalinate enhanced toxicity of fluvalinate.

Animals↗
PubMed1989

Congo red-mediated regulation of levels of Shigella flexneri 2a membrane proteins.

The ability of Shigella spp. to bind Congo red from agar medium is generally correlated with their virulence properties. We used a metabolically active culture of Shigella flexneri 2a to determine the effect of Congo red on its membrane protein profiles. Virulent S. flexneri grown in the presence of Congo red at 37 degrees C showed increased levels of three proteins with Mrs of 43,000, 58,000, and 63,000 (43K, 58K, and 63K proteins) in the Sarkosyl-soluble membrane fractions. The observed phenomenon was temperature dependent. At 30 or 42 degrees C the protein levels remained unaffected by the presence of Congo red. Similar regulation of the levels of the 43K, 58K, and 63K membrane proteins was also observed with Shigella dysenteriae 1 and enteroinvasive Escherichia coli, but not with enteropathogenic E. coli. The cellular uptake of Congo red seemed to be essential, but not sufficient, for regulation. All three proteins reacted with human convalescent-phase sera in immunoblots of S. flexneri 2a Sarkosyl-soluble membrane fractions. Using the 43K-specific antiserum as the primary antibody, by indirect immunofluorescence studies, we detected an increase in the level of the 43K protein in S. flexneri which had invaded epithelial cells. These observations strongly indicate that the 43K, 58K, and 63K proteins are virulence associated. We propose that the observed regulatory effect of Congo red on membrane proteins of S. flexneri is mediated through induction. Since the same regulatory effect was also observed during the invasion of epithelial cells by S. flexneri, it is suggested that Congo red mimics some host tissue factor in vitro.

Adult↗
PubMed1982

Correlation between the protein and mRNA levels for myosin light chains and tropomyosin subunits during chick fast muscle development in vivo.

Using myosin light chains and tropomyosin subunits as representative myofibrillar proteins, we have characterized their isoprotein forms and also correlated them with the accumulation of the corresponding mRNAs during development of a fast muscle in chicken, viz, pectoralis. Both slow and fast myosin light chain isoforms, except fast myosin light chain LC3, and the two subunits of tropomyosin are present in early embryonic muscle. During development, the slow myosin light chains and beta-tropomyosin appear in reduced amounts in pectoralis muscle and finally they disappear in adult muscle. Translation studies with total cellular RNA from developing muscle indicates that while the protein levels of the above isoforms, in general, correlate with the accumulation of corresponding mRNAs, for LC3, additional post-transcriptional control appears to modulate the expression of this isoprotein skeletal muscle development in vivo.

Aging↗
PubMed1979

A model of translational control involving mRNA-associated proteins in chick embryonic muscles.

Highly purified poly(A)-containing free and polysomal mRNP particles have been isolated by chromatography of subcellular fractions of chick embryonic muscles on oligo-dT-cellulose and elution with low salt buffer at 45 degrees. The free and polysomal mRNP represent two distinct classes of macromolecules, the free particles having a more complex nucleoprotein organization than the polysomal particles. Comparison of the protein moieties of three classes of poly(A)-containing cytoplasmic mRNP -- those released from nuclei after in vitro transcription and processing (transported mRNP), the free, and polysomal mRNP -- strongly suggests that the majority of the mRNA-associated proteins are exchanged in the cytoplasm during the various functional states of mRNA. A model of translational control involving the participation of mRNA-associated proteins in chick embryonic muscles and by analogy in other differentiated eukaryotic cells is proposed.

Animals↗
PubMed1979

Release of in vitro-synthesized poly(A)-containing RNA from isolated rat liver nuclei: characterization of the ribonucleoprotein particles involved.

Nuclei isolated from rat liver were incubated under conditions in which RNA continued to be labeled with precursors for long periods. After 1 hr, during which the rate of RNA synthesis was constant, 25-30% of the newly synthesized RNA was recovered in the postnuclear supernatant. About 3-5% of this fraction was characterized as poly(A)-containing ribonucleoproteins by the following criteria: (i) characteristic elution profile in oligo(dT)-cellulose chromatography; (ii) size distribution of the molecules and their deproteinized RNAs; (iii) buoyant densities in CsCl gradients; (iv) presence of RNaseresistant fragments resembling poly(A)-protein complexes; and (v) identification of the protein components by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. The sensitivity of labeling of the RNA synthesized and released from the nuclei to low doses of alpha-amanitin suggests the presence of polymerase II products in the particles. Comparison of the sizes of proteins in these particles with those of free and polysomal messenger ribonucleoproteins as well as with heterogenous nuclear ribonucleoproteins indicates that the released particles contain a protein of 78,000 daltons, which is also present in the other three classes of ribonucleoproteins, presumably at the 3'-poly(A) segments. In addition, a few other proteins, similar in size to those found in the cytoplasmic ribonucleoproteins, were also present in the released particles. It is suggested that proteins associated with heterogenous nuclear RNA are mostly exchanged before or at the time of release of mRNA from the nucleus; the remaining mRNA-associated proteins are added in the cytoplasm, possibly in relation to cytoskeleton attachment, followed by the removal of most of these proteins during polysome formation.

Amanitins↗