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Biomedical subjects

C Sarkar

Publications and source records attributed to C Sarkar.

At least 73 records · Page 4Linked to original sources
PubMed1999

Effect of banana on cold stress test & peak expiratory flow rate in healthy volunteers.

The effect of banana on cold stress induced hypertension, peak expiratory flow rate and plasma ACE activity in healthy human volunteers was tested. Systolic blood pressure (P < 0.005), diastolic blood pressure (P < 0.025) and mean arterial blood pressure (P < 0.005) were significantly decreased during cold stress after banana treatment compared to controls subjected to cold stress. There was no significant changes in heart rate and peak expiratory flow rate but only significant decrease in plasma ACE activity after banana treatment. Banana decreased the rise of systolic blood pressure and diastolic blood pressure in healthy volunteers subjected to cold stress test without much effect on heart rate and peak expiratory flow rate.

Adult↗
PubMed1999

Epilepsy surgery in India: All India Institute of Medical Sciences experience.

OBJECTIVES: Surgical treatment of epilepsy should be considered an important alternative to medical therapy. The identification of a suitable candidate, pre-operative evaluation requires a multidisciplinary team. The specific diagnostic studies required depend on the operative strategy and objective of surgical treatment. METHODS: In twenty patients with medically intractable epilepsy, who had clinical evaluation, electroencephalography (EEG), video-EEG monitoring using scalp electrodes, high resolution magnetic resonance imaging (MRI), neuropsychology, single photon emission computed tomography (SPECT) was done to localise the seizure focus. If the investigations were concordant resective surgery was performed. In case of frequent falls, atonic and tonic seizures, with generalised/multifocal discharges on EEG, a callostomy was done. Surgical outcome was assessed using Engel's 4 point scale. RESULTS: In 18 patients the seizure focus was localised, 13 had temporal lobectomy, five extra-temporal resection, and two had callosotomy. Fifteen patients had a follow-up of more than eight months, mean 20.5 (range 8-35 months), 13 had outcome I (seizure free), two had outcome II (occasional seizures), one-outcome III. Three were lost to follow-up and one patient died. There were no major post-operative complications. CONCLUSIONS: Surgical treatment of epilepsy is a safe, effective mode of therapy. Suitable candidates should be identified early and referred to appropriate centres.

Adolescent↗
PubMed1998

The expression of nitric oxide synthases in human brain tumours and peritumoral areas.

Nitric oxide, a potent signalling molecule produced from L-arginine by nitric oxide synthase (NOS), has been implicated in diverse pathophysiological processes. Many characteristics of malignant tumours such as increased vascular permeability, vasodilation, neovascularisation and free radical injury to the tumour and adjacent normal tissues are believed to be mediated by nitric oxide. While NOS expression has been demonstrated in brain tumours, no equivalent studies have yet been reported on the adjacent peritumoral brain region. The present study examined the pattern of NOS expression in the human tumour and peritumoral brain areas. Biopsies were obtained from eight patients (six gliomas, one each of meningioma and metastatic adenocarcinoma) from three areas: tumour, peritumoral, and apparently 'normal' adjacent brain tissue. Immunohistochemical staining was performed for three isoforms of NOS: brain NOS (BNOS), endothelial NOS (ENOS) and macrophage-specific NOS (MacNOS). Except for glioblastoma multiforme and metastatic adenocarcinoma, the tumour cells expressed all three NOS isoforms. In four tumours, there was a demonstrable gradient of ENOS expression falling away from the tumour. In three gliomas, many glial cells were intensely labelled with BNOS. This labelling decreased in the peritumoral tissues. In four tumours, cells (presumably lymphocytes, and CD 45 positive macrophages) were labelled intensely with MacNOS in and around the blood vessels. These results suggest that nitric oxide is produced in the tumour cells and endothelium of tumour vasculature, while occasionally glial cells may also be induced to produce it. The possible role of nitric oxide in the production of peritumoral oedema is discussed.

Adenocarcinoma↗
PubMed1998

Genetic alterations in brain tumors identified by RAPD analysis.

We report the utility of random amplified polymorphic DNA (RAPD) analysis for identifying subtle genomic alterations in meningiomas and gliomas by comparing the DNA band profile of tumor vis-à-vis its constitutional counterpart. Twenty out of the 29 decanucleotide GC-rich random primers utilized for the RAPD analysis of meningiomas revealed alteration(s) in the tumor genome. In gliomas, changes were detected by 16 of the 18 primers. While all the seven meningioma samples exhibited alterations in tumor DNA, changes were evident in 21 of the 24 glioma cases. These alterations in tumor DNA included the loss of a normal band, appearance of a new band and amplification of a pre-existing band. Many primers detected more than one alterations in a given tumor. Our approach, which covers the range from 0.4 to 2 kb, besides detecting a significant number of changes in a spectrum of brain tumors, complements existing DNA fingerprinting methods, such as microsatellite mapping (less than 0.4 kb) and Southern blotting (over 2 kb), for detecting genetic alterations in tumors.

Brain Neoplasms↗
PubMed1998

Bazex syndrome (acrokeratosis paraneoplastica).

Acrokeratosis paraneoplastica (Bazex syndrome) is a rare but distinctive dermatosis associated with carcinomas of the upper aerodigestive tract with possible cervical lymph node metastases. The cutaneous lesions occurring in the syndrome are non-metastatic skin involvement that parallels (as cutaneous marker) the evolution of the malignancy. Since only a few case reports have been published in the otolaryngologic literature, we present our experience and review some of the findings previously reported.

Acrodermatitis↗
PubMed1998

Gliofibroma: mixed glial and mesenchymal tumour. Report of three cases.

Gliofibromas are rarely encountered astrocytic tumours comprising of astrocytic and benign fibroblastic components. They commonly occur in first two decades of life. However, the exact behaviour is not fully known and their histogenesis is also still debatable. We report three cases of gliofibroma in which we studied proliferative markers (MIB-1) and p53 protein expression. In these tumours, occurrence in adult life is in contrast to that reported in the literature. Depending upon the morphology and proliferative Labelling Index we classified these tumours into low grade (benign) and high grade (malignant/anaplastic).

Adult↗
PubMed1998

A study of proliferative markers in central neurocytoma.

To gain a better insight into the biological behavior of central neurocytomas, various proliferative indices were studied in these tumors and correlated with the histological features as well as the clinical outcome. Twenty cases of neurocytoma were selected over a 16 year period (1980-1995), which accounted for 0.28% of all intracranial tumors reported at this centre. Treatment consisted of surgical resection (total 14, subtotal six) followed by radiotherapy. Except for five patients who died of surgical complications, the remaining 15 were all alive and well during the follow-up period, varying from six months to 72 months (average 32 months). Thirteen tumors showed benign histological characteristics (Group I) while seven showed mitoses + necrosis (Group II). The proliferative index was assessed in formalin-fixed paraffin-embedded tissue of 17 cases using the silver nucleolar organiser region (AgNOR) technique and immunohistochemical staining for proliferating cell nuclear antigen (PCNA-PC10 antibody) and Ki-67 antigen (MIB-1 monoclonal antibody). The AgNOR counts ranged from 1.2 to 2.6 (mean 1.9 +/- 0.4), PCNA labeling index (LI) from 0.1 to 5.5 (mean 2.5 +/- 1.8) and MIB-1 LI from 0.1 to 3 (mean 0.8 +/- 0.02). There was no significant difference in any of these parameter values between histological Groups I and II, except that MIB-1 LI tended to be higher in Group II tumors. Further, there was no significant correlation between these proliferative indices and the mitotic rate of the tumors as well as the survival of the patients. A longer follow-up will be required to determine the relationship between proliferative markers and outcome as well as to bring out any heterogeneity in their biological behavior. Since these are relatively rare tumors, multicentric pooling of data will be required to reach a definitive consensus regarding their biological aggressiveness and consequentially, the use of radiotherapy in their treatment. The present report is a contribution in this direction.

Adolescent↗
PubMed1998

Histopathological changes following the use of biological and synthetic glue for dural grafts: an experimental study.

Dural defects and CSF leaks are common neurosurgical problems and the search for a suitable sealant continues. The effects of such sealants on meninges and brain have not been previously studied. To study the effect of two commonly used sealants, burrholes were made in 20 rats, with the creation of dural tears which were covered with human cadaveric dura smeared with synthetic (cyanoacrylate) glue and gelatine (GRG) glue. Plain dura, placed in one of the burrholes served as a control. An intense inflammatory reaction was observed with both glues, which was found to persist till the eleventh week.

Adult↗
PubMed1998

Hypothalamic hamartoma: report of a case with unusual histologic features.

A rare case of hypothalamic hamartoma with unusual radiologic and histopathological features is described, possibly the first of its type in English literature. A 1.5-year-old female child presented with precocious puberty. MR scan of the brain revealed a pedunculated hypothalamic mass, most of which was isointense with normal brain on T1- and T2-weighted images. However, a sizeable component of the lesion was hyperintense on T1-weighted images, suggestive of adipose tissue. Microscopically, the lesion was a hamartoma composed of an admixture of neuroectodermal elements, namely glial cells, neurons, and nerve bundles along with mesenchymal elements in the form of fibroadipose tissue.

Brain Diseases↗
PubMed1998

Coronary artery lesions in Takayasu's arteritis--clinical and angiographic study.

Two hundred and twenty five patients of Takayasu's arteritis were studied over 13 years. Male:Female ratio was 1:7. Mean age of the study population was 19 +/- 4 years. Of these 225 patients, 75 patients had symptoms and/or signs of cardiac involvement and these patients were subjected to coronary angiography. Significant coronary artery occlusion (i.e. more than 50% narrowing of luminal diameter) was present in 9 patients. Incidence of coronary artery lesions in Takayasu's arteritis is 12% in this study. The proximal segments of coronary arteries were involved while the distal segments were spared. Out of 34 patients with angina pectoris, only 3 patients had significant coronary arterial narrowing.

Adolescent↗
PubMed1998

Diagnostic yield in computed tomography guided stereotactic biopsies.

Fifty three patients underwent computerised tomography (CT) guided stereotactic biopsies from different CT defined zones of attenuation with the Leksell stereotactic apparatus from October 1993 through January 1995. Multiple lesions were seen in 16 cases and 3 of them had multiple rim enhancing lesions. Astrocytoma was the most common histological diagnosis and thalamus was the commonest site of these tumours. The overall positivity rate was 98.2%. Positive yield from the centre of the lesion, peripheral and perilesional areas was 92.1%, 54.7% and 17.6%, respectively. The definite pathological diagnosis was made in 81.1% of cases. Post-operative neurological worsening was seen in 6 patients, of which 2 recovered without any surgical treatment, in 1 patient ventriculo-peritoneal shunt was done post-biopsy whereas in another evacuation of hamatoma was done which relieved headache and vomiting while 2 patients (3.7%) died.

Adolescent↗
PubMed1998

Assessment of proliferative potential of meningiomas using PCNA LI and AgNOR counts.

Seventy-six cases of international meningiomas were studied using staining for Proliferating Cell Nuclear Antigen (PCNA) and silver nucleolar organizer regions (AgNORs) in order to find out any correlation of these parameters to the histological typing of the tumours and their biological behaviour. Histologically, 35 of the 76 cases were benign, 12 atypical and 19 malignant. Ten cases were recurrent. A male preponderance with a male: female ratio of 1.6:1 was noted. Five of 76 cases were in children below 15 years of age. Majority of the tumours were convexity meningiomas. Overall PCNA labeling index (LI) values ranged from 0.1% to 11.0%. Benign group had an LI of 0.9 +/- 1.42 whereas atypical, malignant and recurrent group had LIs of 4.06 +/- 2.33, 2.91 +/- 2.66 and 3.36 +/- 3.76 respectively. One way analysis of variance test showed a significant difference in the distribution of LI between benign versus atypical, malignant and recurrent group (P < 0.05). A highly significant difference was also observed between PCNA LI of recurrent benign group versus non-recurrent benign group (p < 0.01, wilcoxon Rank Sum Test). On further classifying the tumours based on LI values, it was observed that 30 of 41 (73%) cases of combined atypical, malignant and recurrent group (i.e. biologically more aggressive group) had LI of > 1%, whereas 26 of 35 cases (74%) belonging to the benign group had LI of < 1%. Overall AgNOR counts ranged from 1.27 to 3.11. No statistically significant difference was found in AgNOR counts amongst the different groups of meningiomas. There was no correlation between PCNA LI and AgNOR counts. It was thus concluded that PCNA LI but not AgNOR counts in the primary tumour could be of potential value for more accurate assessment of biologic behaviour of meningiomas in conjunction with the conventional A histological parameters.

Adolescent↗
PubMed1997

Loss of heterozygosity of a locus on 17p13.3, independent of p53, is associated with higher grades of astrocytic tumours.

Amongst the human astrocytic tumours, the commonest of primary brain tumours, the clinical outcome of astrocytoma (AS) is significantly better than anaplastic astrocytoma (AA) and glioblastoma multiforme (GBM). Often, low grade tumours can progress to or recur with a more malignant phenotype. Recent loss of heterozygosity (LOH) reports suspect the involvement of a tumour suppressor gene, different from p53, in the 17p13.3 region of the human chromosome. However, the effect of LOH of 17p13.3 region on tumour histology at presentation and prognosis is as yet undefined. As a first step to define the role of this putative oncogene in astrocytic tumour progression, we correlated the LOH of a locus, D17S379, in 17p13.3 region and the p53 locus in 17p13.1 region with the histopathology of astrocytic tumours by PCR based microsatellite and restriction fragment length polymorphism of DNA extracted from microdissected paraffin sections of 45 astrocytic tumours of different histopathological grades. LOH of D17S379 was significantly associated (P=0.02) with AA and GBM (high grade malignancy), while no such preferential association was found with LOH of p53. There were no mutations in the exons 5 to 9 of p53 gene in the five tumours with LOH of D17S379 but not of p53 region. In a case of AA with a heterogenous microscopic appearance, heterozygosity of D17S379 was lost only in the area with a more malignant histology while both areas had no LOH or mutation of p53. A locus at the 17p13.3 region, independent of the p53 locus, is involved in a large subset of astrocytic tumours during transformation into a more malignant phenotype, and thus may be a link in the chain of genetic events occurring in astrocytic tumour progression.

Astrocytoma↗
PubMed1997

Solitary giant skull base schwannomas--report of four cases.

BACKGROUND: Solitary intracranial schwannomas not related to major nerves or neurofibromatosis as well as paranasal schwannomas are rare. Schwannomas simultaneously involving the paranasal sinuses and intracranial cavity are even rarer. METHODS: We report four cases of schwannomas simultaneously involving the intracranial cavity and paranasal sinuses. They were successfully managed by surgery. The literature on such tumors is reviewed. RESULTS: All patients were young adults; the male to female ratio was 1:3. In two patients, the tumor was predominantly intracranial with extension into the sphenoid and ethmoid sinuses, whereas in the other patients, the tumor was located predominantly in the paranasal sinuses and nasopharynx with intracranial extension. Radiologically, bone destruction was seen in three cases. The tumors were totally removed piecemeal with repair of the basal dura. Histopathologic examination confirmed the diagnosis of schwannoma in all four cases. Three patients are alive and well; one of them was reoperated for a recurrence. CONCLUSIONS: These tumors should be excised completely if possible. Radiologically, bone erosion or destruction are suggestive of malignancy but histopathology clinches the diagnosis. Therefore, drastic surgery should be avoided in these cases. Surgery is generally curative in these massive schwannomas.

Adolescent↗