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Biomedical subjects

P Ghosh

Publications and source records attributed to P Ghosh.

At least 397 records · Page 22Linked to original sources
PubMed1977

Organ culture of human articular cartilage: studies on sulphated glycosaminoglycan synthesis.

An organ culture system is described for adult human articular cartilage obtained from joints after femoral head replacement operations. Cartilage slices maintain maximal viability for 2 days in culture as assessed by uptake of [3H]uridine and [3H]leucine into whole tissue, and 35SO4 into sulphated glycosaminoglycans (GAGs). Since GAGs are the components of cartilage matrix, the depletion of which is associated with osteoarthrosis, a method for measuring sulphated GAG synthesis in culture has been investigated.

Adult↗
PubMed1977

Mutagenesis by 4-nitrobenzofurazans and furoxans.

15 nitrobenzofurazans and 10 nitrobenzofuroxans synthesized primarily for testing as potential anti-rheumatic drugs were also tested for mutagenicity in Salmonella typhimurium strains TA98 and TA100. The method used involved placing each compound in a "well" cut out of a plate of selective medium previously seeded with the appropriate tester strain, and then adding a rat liver microsome/cofactor mixture to one of the two wells on each plate. This method is considerably cheaper and more convenient than the conventional agar overlay technique, but in the present series of experiments failed to detect 4 compounds which could be detected by the overlay technique. Using a combination of the two techniques, 21 of the 25 compounds tested were found to be mutagenic. All 10 benzofuroxans and 9 of the 15 benzofurazans were detected as direct-acting mutagens with at least one of the two tester strains. Two of the benzofurazans gave positive results only in the presence of rat liver microsomes, and hence are pro-mutagens. One of the 4 benzofurazans which gave negative results for mutagenicity in these tests was found to be an efficient inhibitor of a neutral protease activity found in rheumatic synovial fluid, and may therefore have some potential as an anti-rheumatic drug.

Animals↗
PubMed1977

Transverse trachero-oesophagoplasty a new one-stage operation for construction of a 'Neo-Larynx'.

A new one-stage operation of constructing a 'Neo-Larynx' after total laryngectomy, transverse tracheo-oesophagoplasty, for a good alaryngeal ('Tracheo-Oesophageal') speech is described. A 'Neo-Epiglottis' is constructed from the posterior tracheal wall and a 'Pseudo-Glottis' in the tracheo-oesophagenal partition wall with a valvular mechanism for preventing aspiration into the trachea during deglutition. No extraneous tissue is used for the construction of the 'Neo-Larynx' and no practice is necessary on the part of the patient for developing alaryngeal 'Tracheo-Oesophageal' speech. The patient can phonate immediately after removal of the feeding tube and the silastic sheet and is ready for discharge five weeks after operation. Adequate surgical ablation is ensured and at the same time good functional rehabilitation is offered without jeopardizing the principles of cancer surgery, i.e. to be on the overdoing side rather than on the underdoing one in a futile attempt at retaining the function.

Esophagus↗
PubMed1977

Endo- and exoglycosidases in an experimental rat osteosarcoma.

Glycosidases capable of degrading intercellular matrix components were investigated in a 32P induced rat osteosarcoma. Homogenates of ossifying tumour were shown to readily degrade hyaluronic acid, chondroitin sulphates 4 and 6 but not dermatan sulphate. High levels of the exoglycosidases, beta-glucuronidase and beta-N-acetylglucosaminidase were found in tumour homogenates, and it was demonstrated that these enzymes contribute to the degradation of high molecular weight hyaluronic acid. The levels of these enzymes were compared with activities found in homogenates of neonatal bone and muscle surrounding tumours. Exoglycosidases, but not hyaluronidase, were found to be produced by cultures of osteosarcoma in vitro.

Animals↗
PubMed1977

Hyperthermia and cancer.

The effects of heat and its possible significance in cance therapy have been documented for more than a century. Hyperthermia has been widely investigated as an alternative or adjuvant to conventional therapies such as surgery, radiation, and chemotherapy. The clinical reports are interesting, notwithstanding some harmful side effects and other complications which, however, may be attributable to an advanced stage of the disease at the time of treatment. In view of the extreme difficulty in matching suitable controls for cancer patients undertaking such therapy, it is essential to extend knowledge of the effects of hyperthermia on normal and neoplastic tissue by experimental studies. Further, the different methods of utilizing heat therapy have need for substantial technological improvements. To stimulate interest in this area, we have gathered together in this review some of the more pertinent reports on the application of hyperthermia to neoplastic and normal tissues as observed clinically and in the laboratory.

Animals↗
PubMed1977

Sulphated glycosaminoglycan synthesis in normal and osteoarthrotic hip cartilage.

The in vitro sulphated glycosaminoglycan metabolism and uronate content of human aged and osteoarthrotic hip articular cartilages have been examined. Cartilages were sampled from nonfibrillated weight-bearing areas and cultured in Dulbecco Modified Eagle's medium with 35SO4. Uptake of 35SO4 was corrected for total sulphate concentration and related to uronate levels after papain digestion and dialysis. The levels of uronate in these tissues varied between 0 - 96% and 2 - 26% dry weight and did not correlate with either osteoarthrotic grading or sulphated glycosaminoglycan metabolism, irrespective of the source. Glycosaminoglycan metabolism of intact hip articular cartilage from clinically defined osteoarthrotics appears, from these results, to be comparable to that derived from nonsymptomatic hip joints from individuals of similar age. Sodium salicylate was found to depress sulphated glycosaminoglycan metabolism in osteoarthrotic cartilage.

Aged↗
PubMed1977

The variation of the glycosaminoglycans of the canine intervertebral disc with ageing. I. Chondrodystrophoid breed.

The variation with age and spinal level of the glycosaminoglycan distribution in beagle (a chondrodystrophoid breed) intervertebral discs have been assessed by means of histochemical and chemical methods. Chondroitin sulphate is the major glycosaminoglycan of the immature beagle disc, but with ageing, this is partially replaced by keratosulphate. The level of glycosaminoglycans in the nucleus pulposus is markedly less than in the nonchondrodystrophoid breed and by 1 year of age, the beagle nucleus pulposus has become largely fibrocartilagious. This alteration in 'normal' disc developments is possibly associated with the elevated incidence of disc disorders in the chondrodystrophoid breeds.

Aging↗
PubMed1977

Variation of the glycosaminoglycans of the intervertebral disc with ageing. II. Non-chondrodystrophoid breed.

The variation with age and spinal level of the glycosaminoglycan distribution in the greyhound (a non-chondrodystrophoid breed) intervertebral disc has been assessed by means of histochemical and chemical methods. The principal glycosaminoglycans of the greyhound disc are the chondroitin sulphates. With ageing, there is evidence of a decline in these components and the replacement by keratosulphate. The discs of this breed contain high proportions of sialic acid and hexosamines well into old age which are thought to be associated with non-collagenous proteins (glycoproteins). The maintenance of glycosaminoglycans and glycoprotein levels in the disc nucleus pulposus into old age is possibly associated with the relatively low incidence of disc disorders in the non-chondrodystrophoid breeds.

Aging↗
PubMed1977

Spinal mobility in the dog. A study in chondrodystrophoid and non--chondrodystrophoid animals.

Spinal mobility in chondrodystrophoid and nonchondrodystrophoid animal has been studied radiographically. Movement at the lumbo-sacral articulation is approximately three times greater than at other levels in the lumbar spine. The L7-L6 articulation is the second most mobile level. Movement at other lumbar segments is approximately equal. The range of motion is closely similar for both skeletal types which suggests that this factor alone is not of crucial importance in the aetiology of intervertebral disc disorder in chondrodystrophoid animals.

Animals↗
PubMed1976

N6,O2'-dibutyryl adenosine 3', 5'-monophosphate-stimulated release of proteoglycans from cultured immature rabbit ear cartilage.

The stimulatory effects of N6, O2'-dibutyrl adenosine 3',5'-monphosphate on proteoglycan released from immature rabbit ear cartilage were studied in viltro. Cartilage incubayed in medium containing dibutyryl cyclic AMP resulted in a significant increase of proteoglycans released in concentrations above 0.5 mM. Theophylline (1 mM) which did not significantly stimulate proteoglycans released alone, was found to potentiate the action of this nucleotide. ATP, 5'-AMP and butyric acid in the presence of theophylline, did not stimulate proteolgycans released. The addition of protein or RNA synthesis inhibitors depressed proteoglycans released by dibutyryl cyclic AMP and theophylline. Gel chromatogrphic and chemical investigation of the proteoglycans released into the culture media in the presence of dibutylic cyclic AMP indicated a reduction in the proportion of protein associated with these complexes. This result, together with enzyme inhbitor studies, leads us to speculate that the observed action of dibutyryl cyclic AMP on rabbit ear cartilages may be mediated by the neutral proteases.

Acetylglucosaminidase↗