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Biomedical subjects

S Ghose

Publications and source records attributed to S Ghose.

82 records · Page 5Linked to original sources
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Heat shock protein 70: role in antigen presentation and immune stimulation.

Heat shock proteins (HSP) when released into the extracellular milieu can act simultaneously as a source of antigen due to their ability to chaperone peptides and as a maturation signal for dendritic cells, thereby inducing DCs to cross-present antigens to CD8+ T-cells. HSP can also act independently from associated peptides, stimulating the innate immune system. Previous results regarding the activation of NK cells by HSP70 cell surface expression on tumour cells and soluble HSP70 will be further covered elsewhere within this issue. For cross-presentation, HSP70-peptide complexes (HSP70-PC) were used from two human melanoma cell lines that differ in the expression of the tumour-associated antigen tyrosinase. Purified HSP70-PC consists of both the constitutively expressed HSC70 and the inducible HSP70. HSP70-peptide complexes purified from tyrosinase positive (HSP70-PC/tyr+) human melanoma cells, incubated with immature DCs, results in the activation of HLA-*A0201-restricted tyrosinase peptide-specific T-cells. Receptor-mediated uptake of HSP70-PC by DCs and intracellular transport are required for efficient MHC class I restricted cross-presentation of chaperoned peptides. Demonstration of HSP70-PC mediated cross-presentation of such non-mutated naturally expressed tumour antigens is of special clinical interest with regard to hyperthermia. Tumour regression and improved local control have been shown within clinical phase II/III trials integrating regional hyperthermia combined with radiation and/or chemotherapy in multimodal treatment strategies. According to the proposed concept, local necrosis induced by hyperthermic treatment induces the release of HSPs, followed by uptake, processing and presentation of associated peptides by DCs. By acting as chaperone and a signal for DC maturation, HSP70-PC might efficiently prime circulating T-cells. Therefore, upregulating HSP70 and causing local necrosis in tumour tissue by hyperthermia offers great potential as a new approach to directly activate the immune system.

Animals↗
PubMedDate not supplied

Efficacy of induction chemotherapy in retinoblastoma, alone or combined with other adjuvant modalities.

BACKGROUND: There are not much data available on the use of newer antimetabolites as an initial treatment modality in retinoblastoma, or their effect on vitreous seedings and de novo foci, especially in the Indian subcontinent. METHODS: To evaluate the efficacy of newer agents as induction chemotherapy, 34 tumors in 22 eyes of 19 children with bilateral retinoblastoma were treated with 2 cycles of carboplatin, etoposide, vincristine, and cyclophosphamide; each cycle was of 1 month duration. The tumor response was evaluated at 2 months and adjuvant salvage modalities (ie, cryotherapy, laser, and/or external beam radiotherapy) were added as needed. The cycles were continued and ophthalmoscopic and ultrasonographic monitorings were performed to determine further tumor response, tumor height regression, effect on vitreous seeds, and other ocular changes. RESULTS: Mean tumor height at presentation was 4.2 mm, which regressed to 2.61 mm at 6 months (P=0.000). The biggest tumor to respond was 12.5 mm, although smaller multiple tumors regressed better. Adjuvant modalities were used in 28 tumor foci in 16 eyes. A follow up of 6 to 24 months (mean, 12.8+/-6.21 months), showed complete regression in 12/34 tumors, partial regression in 15/34, stable disease in 6/34, and 1 tumor progressed despite all therapy. Results in all 6 eyes with vitreous seeds were most gratifying; at 1 year vitreous seeds disappeared in 4 eyes and showed complete calcification in 2. Fresh new lesions were not seen in any eye with complete response after the first 2 cycles of chemotherapy. Recurrences were nil and complications minor. CONCLUSIONS: The overall tumor response (complete and partial) of more than 80% indicates that chemoreduction is an effective modality alone and combined with adjuvant salvage modalities. The results with our treatment regime, even in cases with advanced intraocular retinoblastoma, are encouraging.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

Anatomic variations of foramen ovale.

OBJECTIVES: Foramen ovale is of great surgical and diagnostic importance in procedures like percutaneous trigeminal rhizotomy for trigeminal neuralgia, transfacial fine needle aspiration technique in perineural spread of tumour and electroencephalographic analysis for seizure. This study presents the anatomic variations in dimensions, appearance and number of foramen ovale. METHODS: We studied 35 dried human skulls available in the Department of Anatomy, Manipal college of Medical Sciences, Pokhara, Nepal. Variations in appearance and number of foramen ovale were noted. Length and width of foramen ovale was measured. Comparison with other races and differences between right and left sides were also discussed. RESULTS: Out of 70 sides in 35 adult skulls, mean length and width of foramen ovale was 7.46+/-1.41 mm and 3.21+/-1.02 mm on right side and 7.01+/-1.41 mm and 3.29+/-0.85 mm on left side. Shape of foramen ovale was typically oval in 43, (22 on right, 21 on left) almond shape in 24 (Fig.1, arrowhead; 11 right, 13 left), round in 2(1 right, 1 left) and slit-like in 1(Fig.1, arrow). Bilateral oval foramen was observed in 15 and bilateral almond was in 7. Out of 70 sides in 35 adult skulls 3 (2 left, 1 right) sides had spine on the margin of the foramen (Fig.2, arrow), 3 (2 left, 1 right) had tubercle protruding from the margin (Fig. 3, arrow), 2 (1 left, 1 right) sides had bridge like bony spur dividing the foramen into two compartments(Fig. 2, arrowhead), 9 (5 left, 4 right) had bony plate on the margin of foramen ovale (Fig. 4, arrow). Variant foramen ovale was observed in 24.2%. CONCLUSION: Anatomical variations in size and shape of foramen ovale could be explained by developmental reasons. Considering the immense surgical and diagnostic importance of foramen ovale, this study was worthwhile.

Adult↗
PubMedDate not supplied

Protection from ultraviolet radiation by spectacle lenses available in India: a comparative study.

BACKGROUND: Exposure to ultraviolet radiation (UVR) can result in several ocular ailments. We studied the UV absorption (UV-A and -B bands) in 20 lenses (11 hard resin and 9 glass) commonly available in India as uncut lenses for the purpose of prescription as well as non-prescription wear. METHODS: Using a UV-visible spectrophotometer (Thermo-Spectronic, UV-1 model, Thermo Electron Corporation, USA), the percentage transmittance was scanned between 190 and 400 nm, from which the results at 280, 320, 340, 360, 380 and 400 nm were analysed. RESULTS: At 360 nm (UV-A), 75% of the lenses studied failed to offer 95% protection as recommended by the United States Food and Drug Administration (US FDA). At 280 nm (UV-B), 35% of the lenses failed to offer 99% protection against UV-B. Hard resin lenses showed a higher degree of variation in protection from UV-A. CONCLUSIONS: Most of the lenses studied failed to meet the US FDA recommendations in terms of protection from UV-A. Glass lenses afforded better protection up to 320 nm compared with hard resin lenses. As the claims of lens manufacturers regarding UVR protection fall short of international standards, certification of UVR protection for different lenses should be introduced in India.

Equipment Design↗
PubMedDate not supplied

Fungal flora in congenital dacryocystitis.

In this study, 86 eyes in 66 cases (20 bilateral) of congenital dacryocystitis were analysed for fungal growth. Fungi alone were isolated in 12 eyes (13.95%) and in 14 eyes (16.28%) together with bacteria--a total of 26 positive for fungus in 86 eyes (30.23%). These 26 eyes yielded on fungal culture a total of 28 isolates (in 2 eyes, another fungus was isolated on repeat culture). 11 types of fungi were cultured--C. albicans and A. niger accounted for 5 each out of 28. To the best of our knowledge this is the first report in the literature of fungal flora analysed in congenital dacryocystitis--not surprisingly, more than 30% of eyes were positive for fungus. Systemic studies of fungal flora in dacryocystitis are very few, and hardly any literature on this subject exists in congenital dacryocystitis. This study is an attempt to determine the frequency and clinical significance of fungi isolated from cases of congenital dacryocystitis.

Dacryocystitis↗
PubMedDate not supplied

Clinicobacteriological correlates of congenital dacryocystitis.

One hundred and fourteen eyes with congenital dacryocystitis have been studied clinically and bacteriologically. Gram positive cocci constituted the major bacterial isolates (57.9%) with streptococcus pneumoniae predominating (28.9%). The most effective antibiotic was cloxacillin with an overall efficacy of 77%. Normal conjunctival flora was sterile in majority (75%) of cases. Positive cases showed preponderance of gram positive cocci (21.6%) with staphylococcus albus (13.3%) being the major isolate. Normal nasal flora revealed diphtheroids (alone or in combination) to be the commonest bacteria (62.1%). A statistically significant correlation was not observed between the normal conjunctival or nasal flora and flora from the affected eyes.

Bacteria↗