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Biomedical subjects

Jyotirmay Biswas

Publications and source records attributed to Jyotirmay Biswas.

At least 19 recordsLinked to original sources
PubMed2006

Expressions of Rac1, Tiam1 and Cdc42 in retinoblastoma.

The Rho GTPases are the molecular regulators of the cell motility processes and are involved in cell cycle progression and gene transcription. We studied the expression of Rho-like GTPases molecules, particularly Rac, Tiam1 and cdc42, in retinoblastoma and correlated these with clinicopathological parameters of the tumors. Sixty-seven tumors were included which were divided in to two groups; group A: tumors with optic nerve/choroidal/orbital invasion (n=35) and group B: tumors with no invasion (n=32). Immunohistochemistry was done on paraffin sections for all the proteins and were confirmed by Western blot on fresh tumor samples. In group A tumors, Rac was positive in 10/35 (28%), cdc42 was positive in 12/35 (34%) and Tiam1 was positive in 30/35 (85%) tumors. In group 2 tumors, Rac was positive in 5/32 (15%), cdc42 was positive in 4/32 (12%) and Tiam1 was positive in 30/32 (93%) tumors. Two groups (both invasive and non-invasive tumors) showed decreased expression of Rac1 and cdc42 whereas Tiam1 was significantly expressed in invasive tumors compared to non-invasive tumors (P<0.0001). We observed a 70K cleavage product of Tiam1 along with an 110K product by blotting in RB samples. Caspase-3 was also demonstrated in RB samples, which showed Tiam1 cleavage products. This is the first study that showed the expression patterns of Rac, cdc42 and Tiam1 in retinoblastoma tumors. Thus, further studies are required to prove the involvement of caspase-3 in the cleavage of Tiam1 in vitro in RB cells and to trace out alternative pathways involved in tumor progression.

Adolescent↗
PubMed2006

Ocular tuberculosis in acquired immunodeficiency syndrome.

PURPOSE: To present the clinical, histopathological, and molecular biologic findings in fifteen cases of ocular tuberculosis (TB) in patients with acquired immune deficiency syndrome (AIDS). DESIGN: Retrospective, observational, noncomparative case series of HIV-infected patients with ophthalmic complaints and/or with advanced disease (CD4+ cell count < 200), seen between the years 1993 to 2005 at tertiary care ophthalmic and AIDS care hospitals. METHODS: Each patient underwent a complete ophthalmic examination and relevant laboratory and radiologic investigations and was treated accordingly. The study was carried out in this cohort to describe the ocular manifestations of TB. The main outcome measures were to describe the clinical course histopathologic and molecular biologic features of ocular lesions attributable to tuberculosis in AIDS patients in our center. RESULTS: Ocular TB was seen in 15 (1.95%) out of 766 consecutive cases of HIV/AIDS. Nineteen eyes of 15 patients were affected. Four cases (26.66%) had bilateral presentation. Presentations of ocular TB included choroidal granulomas in 10 eyes (52.63%), subretinal abscess in seven eyes (36.84%), worsening to panophthalmitis in three eyes, conjunctival tuberculosis, and panophthalmitis each in one eye (5.26%). All cases had evidence of pulmonary tuberculosis. Coexistent central nervous system (CNS) tuberculosis was seen in two cases and one case had abdominal tuberculosis. CD4+ cell counts were done in 14 patients; the count ranged from 14 to 560 cells/microl--mean 160.85 cells/microl. CONCLUSIONS: Ocular TB in AIDS is relatively rare and can occur even at CD4+ cell counts greater than 200 cells/microl. It can have varied presentations with severe sight-threatening complications.

AIDS-Related Opportunistic Infections↗
PubMed2006

Expression of insulin-like growth factor receptor (IGF-1R), c-Fos, and c-Jun in uveal melanoma: an immunohistochemical study.

The immunoreactivity of insulin-like growth factor receptor type 1 (IGF-1R), c-Fos, and c-Jun by immunohistochemistry was studied in three groups of uveal melanomas and was correlated clinicopathologically. Immunoanalysis was correlated with cell types, largest tumor diameter, tumor-infiltrating lymphocytes, mitosis, nuclear grade, and extrascleral extension/liver metastasis. In group C (n = 6), tumors with liver metastasis showed higher expressions of IGF-1R (p = 0.0001), c-Fos (p = 0.004), and c-Jun (p = 0.018) compared with the tumors with no extension/extrascleral extension without liver metastasis (groups A-45 and B-9). Further studies are required to elucidate the role of sequential upregulation of these proteins and the transcriptional activity of c-Fos and c-Jun in uveal melanomas with liver metastasis

Adolescent↗
PubMed2006

Recurrent posterior scleritis--report of a case.

Posterior scleritis is a serious ocular inflammatory and potentially blinding disorder. It is uncommon and often under-recognized due to its varied presentations, and general ophthalmologists are not familiar with it. Posterior scleritis may be idiopathic or associated with systemic diseases. Visual disturbances such as blurring or distortion are the commonest symptoms. There may be pain, tenderness, and deep-seated discomfort in and around the orbit. One study reported a 49% recurrence rate of posterior scleritis. Posterior scleritis responds well to systemic nonsteroidal anti-inflammatory agents, systemic steroids, and immunosuppressive agents. Recurrences are known to occur despite therapy. However, multiple recurrences in posterior scleritis are uncommon. We report a patient with posterior scleritis who had one episode in the right eye and four episodes in the left eye over a 35-month period.

Adult↗
PubMed2006

Pseudouveitis--analysis of cases misdiagnosed as posterior uveitis.

PURPOSE: Analysis of non-uveitic entities that were referred as posterior uveitis to a uveitis referral center. METHODS: We came across and analyzed 32 cases of non-uveitic entities (1.12%) that had been misdiagnosed and referred as posterior uveitis out of 2846 outpatient cases of posterior uveitis registered from 1990 to June 2002. The final diagnosis was achieved by history, slit-lamp biomicroscopy, meticulous fundus evaluation, imaging, and ancillary studies. RESULTS: The finally diagnosed 32 non-uveitic entities that mimicked posterior uveitis were multiple leak central serous retinopathy (n = 8; 25%), choroidal neovascular membrane (n = 6; 18.75%), typical central serous retinopathy (n = 4; 12.5%), dry form of age-related macular degeneration (n = 3; 9.3%), retinitis pigmentosa (n = 3; 9.3%), heredomacular degeneration (n = 3; 9.3%), myelinated nerve fibers (n = 2; 6.2%), malignant melanoma of the choroid (n = 1; 3.1%), old spontaneously reattached retinal detachment (n = 1; 3.1%), and subhyaloid hemorrhage (n = 1; 3.1%). CONCLUSION: The purpose of the study was to underline the fact that there are some non-uveitic entities that mimic posterior uveitis and that an ophthalmologist can be deceived. The study highlights the problems diagnosing posterior uveitis and presents an algorithm of diagnostic approach to avoid misdiagnosis.

Adult↗
PubMed2006

Triple agent immunosuppressive therapy in Vogt-Koyanagi-Harada syndrome.

PURPOSE: To describe the role of triple agent immunosuppression in severe recalcitrant cases of Vogt-Koyanagi-Harada syndrome. MATERIALS AND METHODS: Retrospective chart review of five cases of Vogt-Koyanagi-Harada syndrome. RESULTS: All cases were treated with oral prednisolone, azathioprine, and cyclosporine in combination, and rapid remission was observed in all patients. The synergistic effect of the triple agent immunosuppressives helped in preventing recurrences. Prolonged treatment with steroid sparing immunosuppressives in severe and recalcitrant cases of Vogt-Koyanagi-Harada syndrome maintained disease remission. CONCLUSION: Severe cases of Vogt-Koyanagi-Harada syndrome can be treated with early use of high-dose triple agent immunosuppressives.

Adult↗
PubMed2005

Cystic schwannoma of the orbit-a case series.

A schwannoma is an uncommon benign orbital tumor that arises from Schwann cells in the peripheral nervous system. Schwannoma with cystic degeneration is an even more rarely reported entity. Clinical examination alone is inadequate for the diagnosis. Radiological examination, like computed tomography (CT) scans, can help in the diagnosis; however, the diagnosis can only be confirmed by histopathological examination (HPE) after excision biopsy. Here, the authors report four cases of orbital schwannoma with cystic degeneration that presented with proptosis and decreased vision. CT scans showed a well-defined non-enhancing intraconal mass with cystic spaces. The histopathological examination was diagnostic for orbital schwannoma with cystic degeneration. Schwannoma should be included in the differential diagnosis of cystic orbital lesions.

Adolescent↗
PubMed2005

Human leukocyte class I antigen and beta2-microglobulin expression in conjunctival dysplasia, carcinoma in situ, and squamous cell carcinoma.

PURPOSE: Malignant transformation of cells is frequently associated with abnormalities in HLA expression. These abnormalities may play a significant role in the clinical course of the disease because the cellular immune response to tumors relies on concomitant recognition of tumor antigens with self-HLA molecules. Since HLA molecules mediate interactions of tumor cells with specific receptors on T and natural killer (NK) cells, tight control of expression of HLA molecules is critical for initiation and implementation of an effective cellular immune response. There is not much information on HLA class I antigens in conjunctival carcinomas. We studied the immunoexpression of HLA class I antigen and beta2-microglobulin (beta2-m) in conjunctival dysplasias and conjunctival squamous cell carcinomas. METHODS: HLA class I antigen and beta2-m expression were analyzed in 10 conjunctival dysplasias, 6 carcinomas in situ, and in 11 conjunctival carcinomas by immunoperoxidase staining with monoclonal antibodies to HLA class I antigen and beta2-m on the archival clinical samples. Immunoanalysis was done according to the International Histocompatibility Working Group Project Description. RESULTS: HLA class I antigen and beta2-m were heterogeneous in 10 conjunctival dysplasias, negative in 6 carcinomas in situ, and 11 conjunctival squamous cell carcinomas. The difference of immunoexpression for HLA class I and beta2-m among the 3 groups was statistically significant (P <0.001). CONCLUSIONS: HLA class I antigens and beta2-m are decreased in conjunctival dysplasias and negative in carcinomas in situ, and carcinomas. The findings support the role of cytotoxic T lymphocyte-mediated control of tumor growth in the clinical course of conjunctival squamous cell carcinomas.

Antibodies, Monoclonal↗
PubMed2005

Chronic microsporidial stromal keratitis in an immunocompetent, non-contact lens wearer.

An 82-year-old healthy man with unilateral chronic stromal keratitis, initially diagnosed to have viral keratitis and refractory to medical therapy, showed numerous oval, microsporidial organisms, measuring 4-5 m in length in the corneal biopsy. Penetrating keratoplasty, followed by treatment with systemic albendazole and topical propamidine isethionate resulted in resolution of the infection. Electron microscopy of the keratoplasty specimen demonstrated sporoblasts with diplokaryotic nuclei and multiple coils of the filament. The light and electron microscopic features were consistent with microsporidial keratitis.

Aged↗
PubMed2004

Expression of Fas ligand in retinoblastoma.

BACKGROUND: The importance of the Fas-Fas ligand (FasL) mechanism for the immune evasion by tumors provided a strong rationale for the examination of FasL expression in retinoblastoma. In an earlier publication, the authors reported that invasive retinoblastomas decreased Fas expression. Because to the authors' knowledge there is not much information regarding the effect of FasL expression on retinoblastoma, the authors studied the expression of FasL in retinoblastoma and correlated it with invasiveness. METHODS: Thirty-six archival retinoblastoma specimens were divided into 2 groups. Group A (n = 17) was comprised of specimens from tumors with no invasion and Group B (n = 19) was comprised of specimens from tumors with invasion of the choroid (focal, diffuse), optic nerve (laminar, postlaminar, surgical end), and orbit. Sections were immunostained with a monoclonal antibody to FasL and the immunoreactivity was assessed. RESULTS: In Group A, FasL was negative in 100% (17 of 17) of the tumor specimens. In Group B, FasL was expressed in 79% (15 of 19) of the tumor specimens (positive in 9 tumors and heterogeneous in 6 tumors). The difference in FasL expression between the two groups was significant (P < 0.001) CONCLUSIONS: Increased expression of FasL was observed in specimens taken from patients with aggressive tumors. Thus, Loss of Fas and gain of aberrant FasL expression were common features of malignant transformation. The data suggested that the Fas/FasL pathway is potentially immunosuppressive and may be involved in the escape of retinoblastoma cells from immune destruction.

Adolescent↗
PubMed2004

Major histocompatibility antigens and antigen-processing molecules in retinoblastoma.

BACKGROUND: Malignant transformation of cells is frequently associated with abnormalities in human leukocyte antigen (HLA) expression. These abnormalities may play a role in the clinical course of the disease, because HLAs mediate interactions of tumor cells with cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells. Retinoblastoma is the most common intraocular malignant tumor in childhood and is characterized by direct spread to the optic nerve and orbit as well as hematogeneous and lymphatic spread. Little is known about the role of HLA expression in the progression of this malignant disease. METHODS: HLA Class I antigen, beta2-microglobulin (beta2-m), HLA Class II antigens, and the antigen-processing molecules (APMs) of the HLA Class I pathway, including proteasomal subunits (low-molecular mass polypeptide 2 [LMP-2] and LMP-10), the transporter-associated protein (TAP-1) subunit, the binding protein tapasin, and the chaperone molecule calnexin, were studied in 30 archival retinoblastoma specimens by immunohistochemistry. Immunoanalysis was performed based on the International Histocompatibility Working Group Project Description. RESULTS: HLA Class I antigen, beta2-m, HLA Class II antigen, and APMs were positive in 12 tumors with no invasion and were decreased in 13 tumors with choroidal and optic nerve invasion. The difference in HLA and APM expression between the 2 groups was statistically significant (P < 0.001). CONCLUSIONS: Decreased expression of HLA was observed in aggressive tumors and in poorly differentiated tumors. The current findings support a role for both CTLs and NK cell-mediated control of tumor growth in the clinical course of retinoblastoma.

Biomarkers, Tumor↗
PubMed2004

Efficacy and safety of 1% rimexolone versus 1% prednisolone acetate in the treatment of anterior uveitis--a randomized triple masked study.

PURPOSE: To evaluate the efficacy and safety of 1% rimexolone versus 1% prednisolone acetate ophthalmic suspension in the treatment of anterior uveitis. METHODS: A randomised triple masked, parallel comparison of rimexolone and prednisolone acetate ophthalmic suspensions was carried out on 78 patients with acute, chronic and recurrent anterior uveitis. Treatment regimen included instillation of one or two drops of drug one hourly through the waking hours during the first week, two hourly in the second week, four times a day in the third week, two times a day for the first 4 days and once a day for the 3 days in the last week. The patient was clinically evaluated on the 3-4th, 7-10th, 14th, 21st and 28th days. The patient was also reviewed on the 30th day. Anterior chamber cells and flare reactions were compared for evaluating the efficacy of the drugs. RESULT: Rimexolone is as effective as prednisolone acetate ophthalmic suspension in the treatment of anterior uveitis. The largest difference found was 0.1 in the flare reaction (statistically insignificant; p = 0.3) and 0.2 score units (statistically significant; p = 0.01) in the cells. Overall, comparison of the drugs shows no clinical significance in the treatment of anterior uveitis by either drug. Difference in intraocular pressure (IOP) was also statistically insignificant (p > 0.05). However, three patients in the prednisolone acetate group and 1 patient from the rimexolone group showed a rise in IOP. CONCLUSION: Rimexolone 1% ophthalmic suspension is as effective as and safer than prednisolone acetate 1% ophthalmic suspension in the treatment of anterior uveitis.

Acute Disease↗
PubMed2004

Phacoemulsification with intraocular lens implantation in cases of pars planitis.

PURPOSE: To analyze the results of phacoemulsification cataract surgery with implantation of posterior chamber intraocular lenses (IOLs) of different biomaterials in eyes with pars planitis. SETTING: Medical and Vision Research Foundations, Sankara Nethralaya, Chennai, India. METHODS: The records of 86 patients (100 eyes) with pars planitis who had phacoemulsification with IOL implantation between January 1997 and April 2003 were retrospectively analyzed. The eyes were divided into 3 groups depending on IOL biomaterial: poly(methyl methacrylate) (PMMA) (n=32), heparin-surface-modified PMMA (n=39), or acrylic (n=29). The postoperative visual outcome and complications in each group were analyzed. RESULTS: Forty-seven patients were men and 39, women. The mean age was 38 years (range 10 to 65 years) and the mean follow-up, 19.67 months (range 3.00 to 54.53 months). At the final follow-up, 91 eyes (91%) had better visual acuity than preoperatively; 79 had an improvement of 2 or more Snellen lines, 12 had an improvement of 1 Snellen line, 4 had no change, and 5 had a decrease as a result of reactivation of the pars planitis and progression of cystoid macular edema (CME). Significant posterior capsule opacification occurred in 10 eyes (10%), CME in 50 eyes (50%), reactivation of pars planitis in 51 eyes (51%), IOL deposits in 29 eyes (29%), IOL decentration in 1 eye (1%), and anterior capsule fibrosis in 14 eyes (14%). The most frequent cause of poor visual recovery was CME, submacular fibrosis, and epiretinal membrane. There was no statistically significant difference in these complications between the 3 groups. CONCLUSIONS: Phacoemulsification with IOL implantation in eyes with pars planitis was safe and led to good visual outcomes in most cases. The factors in surgical success were control of inflammation, meticulous surgery, in-the-bag IOL implantation, and vigilant postoperative care.

Acrylic Resins↗
PubMed2004

Cataract surgery in sympathetic ophthalmia.

PURPOSE: To analyze the results of cataract surgery in patients with sympathetic ophthalmia. SETTING: Sankara Nethralaya, Medical Research Foundation, Chennai, India. METHODS: This study comprised 66 patients (132 eyes) with sympathetic ophthalmia seen at the uveitis referral clinic between January 1990 and July 2001; 42 eyes (31.8%) had cataract. Cataract surgery was performed in 17 sympathizing eyes and 1 exciting eye (17 patients). The records of these 18 eyes were retrospectively analyzed. Three eyes had extracapsular cataract extraction (ECCE) with intraocular lens (IOL) implantation, 6 eyes had ECCE without IOL implantation, and 9 eyes had phacoemulsification with IOL implantation. The mean follow-up was 28.7 months (range 3 to 60 months). RESULTS: The causes of sympathetic ophthalmia were penetrating trauma (n = 8 eyes), ocular surgery (n = 6), perforated corneal ulcer (n = 2), and cyclocryotherapy (n = 1). The most common cataract type, present in 7 eyes (38.8%), was mixed (posterior subcapsular and posterior polar). Visual acuity improved after surgery in 13 eyes (72.2%). The main factors impairing visual recovery were submacular scar and optic atrophy, which were sequelae of the sympathetic ophthalmia. Posterior capsule opacification was noted in 14 eyes (77.7%); it was visually significant in 6 eyes. There was no significant difference in postoperative inflammation or disease reactivation between the 3 types of surgery. CONCLUSIONS: Cataract extraction in cases of sympathetic ophthalmia can be safely and successfully performed with vigilant preoperative and postoperative control of inflammation, careful surgical planning, and meticulous surgical technique. The final visual outcome, however, depends on the posterior segment complications of the disease.

Adolescent↗