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Biomedical subjects

A K Karak

Publications and source records attributed to A K Karak.

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

Hyalinizing trabecular adenoma--a case report with FNAC histologic, MIB-1 proliferative index and immunohistochemical findings.

Hyalinizing trabecular adenoma is a recently described benign thyroid tumor, almost exclusively occurring in females. The morphological features of this entity overlap with both papillary and medullary carcinoma to varying extent. This, in turn, creates a situation of serious diagnostic pitfall particularly for a false positive diagnosis of papillary carcinoma in fine needle aspiration (FNA) cytology. False consideration of medullary carcinoma is also possible by the unwary especially if staining for Congo red and/or immunostaining for calcitonin is not resorted to. At histologic level, the distinctive architectural pattern is however of great help and thus poses a much lesser danger of misdiagnosis. We relate here our experience in a recently encountered case of hyalinizing trabecular adenoma and describe detailed FNA cytologic and histologic findings along with immunohistochemical profile using a panel of eight monoclonal antibodies. The tumor proliferative potential has also been assessed using MIB-1 (Ki-67) immunostaining. The various pros and cons of diagnostic pitfalls are discussed.

Adenoma↗
PubMed1997

MIB-1 proliferative index in parathyroid adenoma & hyperplasia.

A retrospective study on 22 cases of parathyroid adenoma, 9 cases of primary parathyroid hyperplasia and 14 specimens of normal suppressed glandular tissue was undertaken to determine the usefulness of proliferative index (PI) for discriminating adenoma from hyperplasia, as an adjunct to the existing histological criteria. PI was determined by avidin-biotin-complex immunostaining after high temperature microwave antigen retrieval in paraffin sections, using monoclonal MIB-1 antibody which detects paraffin resistant analogue of cell cycle-associated Ki-67 antigen. PI expressed as percentage positive cell nuclei, was 1.36 +/- 0.62 (range 0.04-2.72) in adenoma, 1.17 +/- 0.83 (0.02-1.98) in hyperplasia and 0.03 +/- 0.02 (0.00-0.06) in normal suppressed glandular tissue. While the difference between normal suppressed glandular tissue and adenoma and hyperplasia was significant (P < 0.001), that between adenoma and hyperplasia was not. We conclude that although PI could distinguish between normal suppressed glandular tissue versus glands with primary hyperparathyroidism, it failed as an additional useful parameter for discriminating between adenoma and hyperplasia, both of which have low but similar proliferative activity.

Adenoma↗
PubMed1996

A grading study of gliomas using computer aided malignancy classification and histologic morphometry.

Forty three cases of astrocytic tumors and mixed gliomas were studied with the aim of evaluating the reproducibility of the Kernohan grading system vis a vis (a) grading using computer-aided malignancy classifier TESTAST 268 and (b) grading by quantitative morphometric evaluation of the various histological parameters of TESTAST 268. These patients were then followed up for variable periods with a maximum of forty months. High inter and intra-observer variability were observed in the Kernohan grading system. TESTAST 268 was found to be simpler, rapid and more reproducible. However, one drawback observed of this system was that it did not completely eliminate inter-observer variability because there was still some subjectivity in assignment of the categorical values against the histological features. Morphometric evaluation of the semi-quantitative assignment values of the 4 histological variables in the TESTAST 268 classifier using Zeiss Morphomat-30 revealed a statistically significant difference between the clusters of the measured quantitative values. A repeat grading using TESTAST 268 and categorical assignment values of histological features derived from the absolute values obtained by morphometry resulted in complete elimination of inter-observer variability. Thus, this study highlights the importance of objectivisation using TESTAST 268 and histologic morphometry in the grading of gliomas. However, since this is a preliminary study on a small number of cases, no cut off values of these measurements have been proposed.

Adolescent↗
PubMed1996

Intracranial intraparenchymal schwannomas: a series of eight cases.

Intraparenchymal schwannomas of the CNS are extremely rare. Between 1979 and 1993 400 cases of intracranial schwannomas were operated on and among them were eight patients with intraparenchymal schwannomas comprising 2% of intracranial benign nerve sheath tumours. Four of them were located in the cerebral hemispheres and two each in the brain stem and in the cerebellum. In two cases, there was associated neurofibromatosis (NF-1 and NF-2, one case each). The age ranged from 6 months to 45 years with a male/female ratio of 3:1 and, surprisingly, six of them were in the left cerebral or cerebellar hemisphere.

Adolescent↗
PubMed1996

Basaloid-squamous carcinoma. A distinct histopathological entity.

Basaloid Squamous Carcinoma (BSC) is an uncommon aggressive neoplasm occurring in the upper aerodigestive tract. Lung as a primary site has only recently been reported. A combination of microscopic features is required to make a diagnosis and to differentiate it from other more common malignancies in these sites. Three cases of BSC including one in the lung are reported. There are no prior published reports of this neoplasms in Indian literature. The study highlights the typical microscopic features and the diagnostic difficulties which may be encountered.

Aged↗
PubMed1995

Unexplained absence of both fallopian tubes with ovary in the omentum.

A rare case of unexplained absence of both fallopian tubes and ovaries from their normal position, resulting infertility is presented. On careful search an ectopic ovary containing dermoid cyst was found in the omentum. Possible mechanism and clinical significance of such a rare occurrence is discussed.

Adult↗
PubMed1995

A correlative study of in vivo and in vitro labeling index using bromodeoxyuridine in human brain tumors.

The labeling index (LI) of 216 cases of human brain tumors was determined by the immunohistochemical technique with monoclonal antibody to bromodeoxyuridine (BrdU). The proliferative potential of 110 cases was estimated using the intra-operative intravenous infusion of BrdU at a dose of 200 mg/sq m. In another 106 cases, the in vitro technique of incubating freshly resected tumor tissue fragments with 100 microM bromodeoxyuridine was used. The BrdU LI in these tumors was then correlated with the histological types and the data as determined by both the in vivo and in vitro BrdU incorporation were compared. The results indicate that although in vivo and in vitro techniques could possibly provide equivalent data in some histologic types, a clear statistically valid proof however is not apparent from this study.

Adolescent↗
PubMed1994

Liposarcoma of the mesocolon--case report of a rare lesion.

A middle-aged man with a 2-month history of lower abdominal pain was found to have a large left-sided abdominal lump. Radiological investigations (barium enema, ultrasound, and computed tomography scan) revealed a mass lesion in the area of the descending colon, the sigmoid colon, and the rectum. Flexible sigmoidoscopy showed only mucosal edema and luminal narrowing. At laparotomy, a diffuse thickening of both the descending and sigmoid mesocolon extending into the mesorectum was seen, which suggested an inflammatory pathology. A left hemicolectomy with Hartmann's procedure was performed. After obtaining a histopathological diagnosis of liposarcoma of the mesocolon, an abdominoperineal resection of the rectum was done. The patient was advised to undergo postoperative radiotherapy but he did not comply and was thereafter lost to follow-up.

Humans↗
PubMed1994

Cell culture studies on human nerve sheath tumors.

The main controversy about nerve sheath tumors (NSTs) has been their histogenesis. A Schwann cell origin has been proposed by many investigators for both schwannomas and neurofibromas. However Erlandson and Woodruff observed that while schwannomas appeared to be composed predominantly of Schwann cells, neurofibromas consisted of mainly perineurial cells. In addition, variable numbers of fibroblast-like cells and intermediate cells also have been reported in the 2 lesions. Whether these represent distinct cell types or variants of Schwann cells is still debatable. In an attempt to solve this controversy, the present study was undertaken to observe the morphology and the behaviour of these tumors in culture. These studies showed that all nerve sheath tumors are basically of Schwann cell origin and that intermediate cells and fibroblasts are variants of Schwann cell. Tissue culture studies done chiefly on schwannomas showed that the morphological features of schwannomas are preserved in 'in vitro culture' condition and therefore the difference between neurofibroma and schwannoma appears to be due to inherent differentiating property of the Schwann cells along with some environmental stimulus.

Adolescent↗
PubMed1993

A sequential cell kinetic study of meningioma cells in primary explant culture using bromodeoxyuridine.

The present study was undertaken to evaluate the sequential BrdU-LI at weekly intervals upto four weeks in 18 primary explant cultures of meningiomas. This revealed three distinct patterns of growth which could be arbitrarily defined as 'degenerating' (group I), 'proliferating' (group II) and 'adaptive' (group III) types. Interestingly two cases of malignant and two of recurrent meningiomas fell into the 'degenerating' group I pattern. The possible explanations for the observed relatively higher in vitro LI values compared to lower in vivo values as reported in the literature and the theoretical implications of the three distinct patterns of sequential LI values are discussed.

Adult↗
PubMed1993

Morphological appearance, growth kinetics and glial fibrillary acidic protein (GFAP) expression in primary in vitro explant culture of astrocytic neoplasms.

Astrocytomas of different grades of malignancy were cultured as primary explant and their sequential growth pattern, glial fibrillary acidic protein (GFAP) expression and labelling index (LI) using bromodeoxyuridine (BrdU) were assessed and correlated with the grade of malignancy of the original tumor tissue. Low-grade astrocytomas showed patterns of growth that diverged from anaplastic astrocytomas and glioblastoma multiforme. The GFAP expression decreased with increasing time in culture in all astrocytomas irrespective of the grading. Maximum GFAP was, however, expressed in the morphologically well-differentiated stellate cells. Contrary to expectations, lower BrdU LI was observed in glioblastoma multiforme in comparison to low-grade astrocytomas, which suggests some unidentified mechanism of differentiation in vitro for astrocytomas of higher grade of malignancy. Hence, in contrast to reported literature on the prognostic value of studies on primary cultures, the present study cautions the extrapolation of the in vitro findings for astrocytomas.

Adolescent↗
PubMed1992

Urinary bladder carcinoma as apparent cause of antepartum haemorrhage in pregnancy.

A 34-year-old multipara presented with painless profuse genital bleeding during the third trimester of pregnancy in a state of hemorrhagic shock. Haematuria because of urinary bladder carcinoma was found to be the cause of bleeding. Cystoscopy was useful for accurate diagnosis as well as for achieving haemostasis. This case emphasizes the possibility and importance of haematuria when dealing with a patient with antepartum haemorrhage.

Adenocarcinoma, Mucinous↗
PubMed1987

Bone marrow recovery following fetal liver infusion (FLI) in aplastic anaemia: morphological studies.

Twenty-two of 35 patients with aplastic anaemia who received fetal liver infusion (FLI), responded to this treatment. Detailed review of bone marrow aspirates and biopsies was available in 17. There was a good correlation between clinical improvement and blood counts. The bone marrow cellularity increased to 48 percent in about 18 weeks with repopulation by both erythroid and myeloid cells. The erythroid response was predominant and the earliest to occur (1.5-61 weeks); it lasted for 7.5-100 weeks. Marked dyserythropoiesis was observed. Myeloid response occurred simultaneously in 45 percent of the responders; in the others it was delayed by 1.5 to 4 weeks. Significant dysmyelopoiesis with shift to the left, unrelated to infection, was seen 1.5 to 9.5 weeks after FLI lasting for 9-26 weeks in most cases. Megakaryocytic response either did not occur or was delayed, less marked and often transient.

Anemia, Aplastic↗
PubMed1987

Tritiated thymidine labeling index in Indian childhood acute lymphoblastic leukemia.

Tritiated thymidine labeling index (LI) was determined in 25 unselected children with cytochemically proved ALL, at various stages of the disease. All the cases were treated by a uniform therapeutic protocol. Pretreatment LI determined in 15 cases showed an inverse correlation with the duration of first complete remission. LI was also studied during remission in 23 patients. Six out of these 23 patients relapsed within subsequent 90 days, while the rest continued to be in remission. Mean LI of the nonerythroid cells in later group of patients was found to be significantly higher than that of the patients who relapsed.

Acute Disease↗