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Biomedical subjects

R K Sinha

Publications and source records attributed to R K Sinha.

At least 37 records · Page 2Linked to original sources
PubMed1998

Mechanism and specificity of immunoprotection induced by mycobacterial proteins against experimental tuberculosis in mice.

Mechanism of immunoprotection and specificity of two highly immunoprotective mycobacterial proteins, viz. 71 and 30 kDa were investigated. The adoptive transfer studies indicated that immunoprotection was mainly mediated by cooperative effect of CD4+ and CD8+ (66.7-73.3% on the basis of percent survival) which was further enhanced marginally by supplementation of B cells, natural killer cells, dendritic cells, macrophages and other immune cells. The specificity studies indicated that both the proteins did not cross react with the unrelated intracellular pathogens i.e. Aspergillus fumigatus, Salmonella typhi and Leishmania donovani as seen by T cell proliferation assay. The protection imparted by these mycobacterial proteins was also specific as the 71 and 30 kDa primed mice did not exhibit any cross protection against sublethal challenge of S typhi. The results indicate 71 and 30 kDa mycobacterial proteins to contain T cell specific epitopes responsible for specific immunoprotection, thus indicating their potential role as antituberculous vaccine candidates.

Animals↗
PubMed1997

The protective efficacy of a liposomal encapsulated 30 kDa secretory protein of Mycobacterium tuberculosis H37Ra against tuberculosis in mice.

The immunoprotective efficacy of the 30 kDa secretory protein isolated from mid-log phase culture filtrate of Mycobacterium tuberculosis H37Ra was investigated using liposomes as adjuvant. Immunization of animals with the 30 kDa protein entrapped in liposomes prepared by a freeze-thaw method and absorbed on alum induced both cellular (monitored by T cell proliferation assay and cytokine secretion, viz. IL-2, IFN-gamma) and humoral (evaluated by ELISA) responses which were comparable to those induced in the 30 kDa IFA-immunized group. The protection induced by liposome-encapsulated 30 kDa secretory protein was slightly lower than that induced in 30 kDa IFA-immunized animals on the basis of higher survival rates and decreased viable counts of M. tuberculosis H37Rv in various organs (spleen, lung and liver) after 30 days of infection compared to the controls. The results strongly indicate that liposomes are an ideal vaccine delivery system which can effectively replace IFA for the delivery of the immunoprotective 30 kDa secretory protein of M. tuberculosis H37Ra.

Adjuvants, Immunologic↗
PubMed1996

Regulation of human osteoblast integrin expression by orthopedic implant materials.

Integrins are transmembrane proteins that mediate attachment to extracellular matrix (ECM) proteins. Integrins act as ECM receptors and are believed to play a role in signal transduction and gene regulation, potentially influencing several cellular functions, including differentiation, growth, and migration. Several integrins have previously been found in bone cells in vivo and in vitro. Because the biologic fixation of orthopedic implants depends on optimal cell interactions at the interface, we examined whether integrins are involved in the attachment of osteoblasts to implant materials. In this study, we have used immunohistochemistry to examine the expression of integrins in primary human osteoblasts cultured on tissue culture polystyrene (PS), and rough and polished disks of the orthopedic alloys titanium-aluminum-vanadium (Ti) and cobalt-chrome-molybdenum (CC). The integrin subunits, alpha 2, alpha 3, alpha 4, alpha 5, alpha v, alpha 6, beta 1 and beta 3, were expressed by primary human osteoblasts cultured on PS coated with various ECM molecules. However, alpha 5 and alpha 6 were notably absent in cells attached to the alloys. Also, alpha 3 was not present on rough Ti, polished CC, or rough CC, and beta 3 was not expressed by cells on rough CC. Thus, the nature of the metal alloy appeared to influence the expression of particular integrins. As a result, the ability of cells to adhere to and receive messages from the extracellular matrix may also be influenced by the substratum. These differences may explain previously observed differences in degree of cell attachment to these metals.

Alloys↗
PubMed1996

C-reactive protein as an indicator of complications in bacterial meningitis.

OBJECTIVE: To determine the value of serum C-reactive protein (CRP) estimation in the follow-up of bacterial meningitis (BM). DESIGN: Longitudinal follow-up. SETTING: Urban hospital. METHODS: Sequential serum CRP estimation was done in 50 healthy children and in 100 children with BM. Serial serum CRP value was correlated with the clinical picture in BM. RESULTS: Serial serum CRP in 14 patients with complicated BM was significantly different than the 72 uncomplicated BM cases. CONCLUSIONS: Serial determination of serum CRP may be a cheap, simple and reliable prognostic indicator in BM.

Bacteria↗
PubMed1994

Surface composition of orthopaedic implant metals regulates cell attachment, spreading, and cytoskeletal organization of primary human osteoblasts in vitro.

The nature of orthopaedic implant surfaces affects the interaction between bone and the implant. To analyze this interaction at a cellular level, this study examined the early phase of cell adhesion to implant surfaces. Using an in vitro model, the cell adhesion of primary human osteoblasts cultured on Ti6A14V (Ti), CoCrMo (CC), and tissue culture polystyrene (PS) was characterized. The osteoblasts were found to adhere in greater numbers to Ti compared with PS and CC during a 12 hour period. Other cellular characteristics related to cell adhesion, such as cell spreading, cytoskeletal organization, and focal contact formation, were also examined. Osteoblasts cultured on Ti were significantly larger, and spread better, compared with those on PS and CC. Also, the rate of cytoskeletal reorganization was enhanced on Ti. Focal contacts remained peripherally located in cells on Ti and CC as cytoskeletal reorganization proceeded. However, for cells on PS, the focal contacts quickly became dispersed along actin filaments. There was no difference between surfaces in the number of cells forming focal contacts, although the cells used a larger percentage of their membrane to attach to CC. These data suggest that osteoblast attachment to Ti is greater because cell spreading and cytoskeletal organization are enhanced. Furthermore, the mechanisms of osteoblast attachment to the underlying substrate may be significantly different between biometals and tissue culture plastic. Substrate specific information regarding the characteristics and mechanisms of cell adhesion may be helpful in the design of implants to optimize bone growth at the interface.

Alloys↗
PubMed1993

The oxazolidinone antibacterial agent DuP 105 does not act on cell wall biosynthesis or on a beta-lactamase.

(S)-3-(4-Methylsulfinylphenyl)-5-(acetamidomethyl)oxazolidinone (DuP 105; 1, R = CH3SO, R' = Ac), one of a new class of antibacterial agents, is shown to be devoid of inactivation and inhibitory properties toward bacterial cell wall biosynthesis and toward a beta-lactamase. This is consistent with the idea that this class of compounds acts by a route different from that of the beta-lactam antibiotics.

Anti-Bacterial Agents↗
PubMed1991

Biosynthesis of peptidoglycan in Gaffkya homari: on the target(s) of benzylpenicillin.

The formation of acceptor for the N epsilon-(D-Ala)-acceptor transpeptidase is an essential feature of nascent peptidoglycan processing. In Gaffkya homari the synthesis of cross-bridges in peptidoglycan includes a variety of penicillin-sensitive enzymes, e.g., transpeptidase, DD-carboxypeptidase, and LD-carboxypeptidase. To determine the primary target, we grew cultures in the presence of the MICs of benzylpenicillin (0.2 microgram/ml), methicillin (10 micrograms/ml), cephalothin (5 micrograms/ml), and cefoxitin (25 micrograms/ml) and examined the monomer-dimer composition of each peptidoglycan by high-performance liquid chromatography after muramidase digestion. From these studies it was recognized that of all the dimers, the synthesis of the predominant cross-bridge, diamidated octapeptide (-Ala-iso-D-Gln-Lys-D-Ala -Ala-iso-D-Gln-Lys-D-Ala), is most sensitive to the action of the beta-lactam at its MIC. The enhanced deamidation of the acceptor tetrapeptide, one of the substrates for the transpeptidase, is correlated with the inhibition of this cross-bridge. For example, at the MIC of benzylpenicillin, the ratio of amidated tetrapeptide to nonamidated tetrapeptide decreased from 2.8 in the control to 1.0 in the treated culture. From these results it would appear that a decrease in preferred acceptor for the transpeptidase results in the inhibition of synthesis of this major cross-bridge. Thus, the metabolism of the amide function of the monomer peptides may represent an additional feature of processing in the assembly of cross-bridged dimers in the peptidoglycan of this organism that is sensitive to the action of beta-lactam.

Chromatography, High Pressure Liquid↗
PubMed1991

A comparative study of the morphology and anatomy of the olfactory organs of two marine fishes with different habitats--Trichiuris savala (Cuv. et Val.) and Tetrodon leopardus (Russel).

The authors carried out a comparative study of olfaction in two marine fishes. The olfactory organs of Trichiuris savala (a middepth feeder) were found to be well developed and capable of detecting smells, whereas in Tetrodon leopardus, which is a bottomfeeder and preferably frequents the sea-bed, the olfactory organs have been secondarily modified to mushroom-shaped bosses.

Animals↗
PubMed1991

Comparative study of the olfactory organs of two hill-stream fishes--Labeo boggut (Sykes) and Ailia coila (Ham.).

The paper presents a comparative study of the olfactory organs of two hill-stream fishes--Labeo boggut and Ailia coila. It was found that the olfactory organs of Labeo boggut were less well developed than those of Ailia coila, in which olfactory area is greater than in Labeo boggut. According to Teichmann's (1954) classification, Labeo boggut belongs to group I, whereas Ailia coila belongs to group II.

Animals↗
PubMed1990

Fine needle aspiration biopsy of spleen in kala-azar.

Fine needle aspiration biopsy (FNAB) of spleen was done in 88 suspected cases of Kala-azar. Leishmania donovani (LD) bodies were demonstrated in 56 cases (63.7%) and malarial parasites in 2 (2.3%) while one (1.1%) had picture of chronic myeloid leukemia and another (1.1%) showed acid fast bacilli (AFB) on Ziehl Neelsen staining. Thirty two cases (36.4%), where LD bodies were not found, were subjected to bone marrow examination and none showed LD bodies. There were no complications after FNAB even though 6 patients were having epistaxis. FNAB of spleen is a simple, economical, safe and reliable diagnostic procedure which can be adopted even in remote areas.

Animals↗
PubMed1990

Morphology and anatomy of the olfactory organs of the marine fish Thynnus thunnina (Cuv. et Val.).

The authors studied the morphology and anatomy of the olfactory organs of the marine fish Thynnus thunnina. The fish has a single nasal orifice. The round olfactory rosette has a central axis surrounded by radially oriented lamellae. The olfactory rosette (olfactory organ) is provided with two accessory nasal sacs - a lacrimal and an ethmoidal sac. Thynnus thunnina was classified in Teichmann's (1954) group II, i.e., the "eye-fishes", whose vision is better developed than their olfaction.

Animals↗
PubMed1989

Morphometric study of stratum corneum in leprosy.

Abnormalities in Stratum Corneum (SC) in leprosy lesions have been demonstrated as evidenced by poor hydration power of SC and increased SC turn-over. In continuation of the same study morphometric studies of the SC in leprosy was undertaken as per measurement of the Thickening of the SC, Mean epidermal thickness and Basal layer: Granular layer cell ratio (B : G ratio) of the H.E. stained tissues. Further, on freshly frozen tissues the SC cell-layers were also counted. The findings suggest increased proliferative activity of the epidermis which may lead to formation of defective SC in leprosy.

Adolescent↗