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R Chetty

Publications and source records attributed to R Chetty.

At least 127 records · Page 7Linked to original sources
PubMed1996

The immunoexpression of bcl-2 and p53 in Kaposi's sarcoma.

The aim of this study was to examine the immunohistochemical expression of p53 and bcl-2 in Kaposi's sarcoma and relate this with proliferation index (as measured by MIB-1 staining) and clinicopathological subtypes. Twenty formalin-fixed, paraffin-embedded cases of Kaposi's sarcoma were stained with commercially available antibodies to p53, bcl-2 and MIB-1, after pressure cooking antigen retrieval. All cases were strongly positive for bcl-2 with the majority containing more than 75% positive cells. In comparison, p53 expression was less striking. Eleven cases contained less than 24% (+1) of cells staining positively. Only two cases showed greater than 75% of positive cells, and both of these latter two lesions had metastasized. The MIB-1 staining in all cases of Kaposi's sarcoma was strongly positive, irrespective of clinicopathological type, in keeping with the highly proliferative nature of this lesion. Thus, we have demonstrated uniformly increased expression of bcl-2 protein in Kaposi's sarcoma irrespective of clinicopathological subtype and MIB-1 staining, while p53 expression is relatively less common, except in those cases which have metastasized. This may help identify those cases that will behave in a more aggressive manner. However, more cases need to be evaluated to verify this.

Adolescent↗
PubMed1996

Thymidine phosphorylase expression in Kaposi sarcoma.

AIMS: To examine the immunohistochemical distribution of thymidine phosphorylase (TP) in all clinicopathological subtypes of Kaposi sarcoma. METHODS: Thirty two biopsy specimens of Kaposi sarcoma (29 patients) were studied. Six of these patients represented classic, six endemic, eight HIV associated, seven post-immunosuppression/transplant related, and two unclassified variants of Kaposi sarcoma. The average age was 49 years (range 22-83 years) and the male: female ratio 24:5. Four samples of angiosarcoma and one of spindle cell haemangio-endothelioma were stained in parallel. All specimens were fixed in formalin, embedded in paraffin wax and processed routinely. Immunohistochemistry was carried out using an antibody directed against CD31 (JC70) and the monoclonal antibody P-GF.44C against TP. RESULTS: All biopsy specimens showed immunoexpression for TP. The spindle cell component stained more strongly than newly formed endothelium lined vessels and normal, resident vessels at a distance from the lesions. CONCLUSIONS: The strong immunoexpression of TP suggests up-regulation of TP and a role for TP in angiogensis in Kaposi sarcoma. The mechanism for the up-regulation of TP remains unknown, but viral infections may trigger it. The differential staining of the various cell components of Kaposi sarcoma also suggest that TP either plays a role in the differentiation and maturation of Kaposi sarcoma or is a reflection of such changes.

Adult↗
PubMed1995

A single center randomized trial assessing use of a vascular hemostasis device vs. conventional manual compression following PTCA: what are the potential resource savings?

We undertook a randomized controlled trial comparing VasoSeal, a collagen vascular hemostasis device (VHD), with manual compression to assess its role and potential cost savings in the PTCA population. Of 460 patients, 359 were excluded due to clinical instability (30%), groin problems (18%), suboptimal PTCA result (15%), and other reasons (37%). The remaining 101 patients were randomized to either VHD (51) or manual compression (50). Hemostasis time, time to ambulation, duration of hospital stay, and nursing time and intensity were significantly reduced in the VHD group. There were no major groin complications in either treatment arm but there was a trend toward more minor groin complications in the VHD patients. The application of VasoSeal reduced resource use in this randomized study and may translate into significant cost reductions in the general coronary angioplasty population.

Adult↗
PubMed1995

SCL/Tal-1 expression in T-acute lymphoblastic leukemia: an immunohistochemical and genotypic study.

A comparative study of the immunohistochemical (Stem cell leukemia/T-cell acute leukemia [SCL/TAL-1] protein expression) and genotypic (deletions in the SCL/tal-1 gene) findings in T-acute lymphoblastic leukemia (T-ALL) is presented. Formalin-fixed tissue from 50 cases of T-ALL were stained with a novel monoclonal antibody, 2TL 242, which recognizes SCL/TAL-1 protein. Twenty-four cases showed nuclear immunolabeling of leukemic cells. Nuclear positivity was not evident in any other type of leukemia or lymphoma tested with the antibody. Genotypic analysis of 25 cases of T-ALL showed a deletion involving the SCL/tal-1 gene in nine cases. These results suggest that protein expression is not dependent on derangement of the SCL/tal-1 gene, because immunohistochemical detection of the protein was noted in the presence and absence of a tal-d1 deletion.

Base Sequence↗
PubMed1995

Primary Hodgkin's disease of the lung.

Three cases of Hodgkin's disease presenting primarily in the lung are described. All 3 patients presented with respiratory symptoms and chest X-rays revealed discrete masses within the lung parenchyma. CT examination of the mediastinum did not reveal regional or generalized lymphadenopathy at the time of diagnosis in 2 of the cases. A diagnosis of Hodgkin's disease was made on open lung biopsies and despite aggressive chemotherapy, 2 patients died within 2 yrs. The histological and immunocytochemical features of these cases were typical of that expected in Hodgkin's disease. However, the stated indolent course of primary pulmonary Hodgkin's disease is not invariable. Those patients with bilateral interstitial disease and systemic symptoms have a poor prognosis. Furthermore, it is difficult to exclude definitely lymph node involvement (although not enlarged) at the time of diagnosis. Since several cases described in the literature have concurrent and/or subsequent nodal involvement, the entity of primary pulmonary Hodgkin's disease without lymph node involvement is exceedingly rare.

Adult↗
PubMed1995

TAL1 gene deletions and TAL1 protein expression in sporadic melanoma.

Studies on cytogenetic abnormalities and cell lines have implicated chromosome 1p32 as being important in the pathogenesis of melanoma. Genetic linkage studies have also mapped a melanoma-susceptibility locus to chromosome 1p. The gene TAL1 is present on chromosome 1p32, and deletions within it are the commonest chromosomal abnormality in T-acute lymphoblastic leukaemia (T-ALL). A melanoma cell line harbouring a 1p32 deletion involving the TAL1 gene and the presence of TAL1 protein in developing mouse melanocytes led us to investigate whether TAL1 deletions and/or TAL1 protein expression occur in sporadic melanomas. DNA extracted from 32 fresh melanomas was amplified by standard polymerase chain reaction for the four common deletions of the TAL1 gene that occur in T-ALL. In addition, frozen and paraffin-embedded sections of these melanomas were stained with monoclonal antibodies that detect full-length and truncated TAL1 protein. The results of the study show that deletions of TAL1 do not occur in melanoma. Indeed, full and truncated TAL1 protein also could not be detected immunohistochemically in the paraffin-embedded and frozen sections of the melanomas. We conclude that the TAL1 gene and its protein are probably not directly involved in the oncogenesis of melanomas.

Base Sequence↗
PubMed1995

Immunohistochemistry in apparently normal bone marrow trephine specimens from patients with nodal follicular lymphoma.

AIM: To establish the role of immunohistochemistry (using a limited panel of antibodies) in detecting minimal involvement by follicular lymphoma in routinely processed bone marrow trephine specimens, which show no obvious morphological (light microscopic) evidence of lymphoma; to determine whether bcl-2 immunostaining in bone marrow distinguishes between benign and malignant infiltrates in a patient with nodal follicular lymphoma. METHODS: Twenty seven consecutively selected paraffin wax embedded, formalin fixed bone marrow trephine specimens were stained with the following antibodies: anti-bcl-2, anti-CD79a, anti-CD3, and kappa and lambda light chains, using the Streptavidin biotin complex technique. RESULTS: Five of the 27 cases, which showed no evidence of involvement by follicular lymphoma on routine stains, showed monotypic B cells on immunohistochemistry. Two of the cases were diffuse, while the remaining three showed mini-aggregates around bony trabeculae. In all five cases the lymphomatous infiltrates were strongly bcl-2 positive. Reactive B lymphoid nodules did not show the same degree of bcl-2 positivity, and negative cells could be discerned within the reactive nodules. CONCLUSIONS: There is merit in studying so-called negative bone marrows immunohistochemically in order to detect minimal involvement by follicular lymphoma. A limited panel of antibodies including anti-bcl-2, anti-CD79a and anti-CD3 is usually adequate to accomplish this. Strongly bcl-2 positive lymphoid aggregates in the bone marrow of patients with nodal follicular lymphoma are indicative of lymphoma.

Biopsy↗
PubMed1995

Immunohistochemical detection of p53 and Bcl-2 proteins in Hashimoto's thyroiditis and primary thyroid lymphomas.

AIMS: To investigate whether immunohistochemical staining using p53 and/or bcl-2 distinguishes between florid Hashimoto's thyroiditis and low grade mucosa associated lymphoid tissue (MALT) lymphoma of the thyroid. METHODS: Ten cases of Hashimoto's thyroiditis and eight of primary thyroid lymphoma were stained with monoclonal antibodies directed against p53 and bcl-2. RESULTS: In Hashimoto's thyroiditis most small lymphoid cells in mantle zones, within the thyroid parenchyma and in lymphoepithelial lesions expressed bcl-2 protein. Very occasional centroblasts in reactive germinal centres were positive for p53, but all other lymphoid cells from cases of Hashimoto's disease were negative for p53. In diffuse, low grade lymphomas bcl-2 protein was uniformly expressed by most tumour cells. However, low grade lymphomas with a follicular pattern did not express bcl-2. The diffuse, low grade lymphomas were negative for p53, while occasional larger cells in the follicular subtype were positive. Both high grade lymphomas were bcl-2 negative but strongly p53 positive. CONCLUSIONS: This study indicates that there is an inverse correlation between p53 and bcl-2 immunostaining in thyroid lymphomas (low grade lymphomas: bcl-2 positive, p53 negative; high grade lymphomas: bcl-2 negative, p53 positive). Furthermore, immunohistochemical staining for bcl-2 and p53 proteins does not distinguish florid Hashimoto's thyroiditis from diffuse, low grade thyroid lymphoma.

Biomarkers, Tumor↗
PubMed1995

Subungual melanoma.

Twenty (1.5%) of 1,350 patients with malignant melanoma treated during a 17-year period had their primary lesion in the nail bed. The thumb (5 patients) and big toe (7) were the most commonly involved digits. Mean delay before diagnosis was 1.4 years. Thirteen patients were black and 7 white. Eight patients (40%) were initially misdiagnosed as having traumatic, infective or benign lesions. Four patients presented with recurrent local disease after inappropriate nail excision or inadequate nail biopsy, while 2 patients had regional nodal spread and 2 had systemic metastases. Mean Breslow depth was 5.7 mm. The histogenetic subtypes were acral lentiginous melanoma (12 patients) and nodular melanoma (4 patients); 4 lesions were unclassifiable. All patients underwent amputation of the involved digit and 12 required node dissection (therapeutic in 11, prophylactic in 1). Five patients (25%) are alive (mean 52 months, range 29-99 months); 4 are disease-free and 1 has brain metastases. Overall median survival was 32 months with a 26% 5-year survival rate. Delayed diagnosis and advanced disease at presentation contributed to the poor prognosis in nail bed melanoma.

Adult↗
PubMed1994

Paraganglioma-like (hyalinizing trabecular) adenoma of the thyroid revisited.

The aim of the present study was to explore the association between paraganglioma-like adenomas of the thyroid (PLAT) and chronic lymphocytic thyroiditis (CLT) or Hashimoto's thyroiditis, and to discuss its possible relationship to papillary thyroid carcinoma. Six cases were analyzed by standard histopathological and immunohistochemical techniques. All 6 cases (all females) had clinical and/or histological evidence of CLT. Only one patient had 2 PLATs. The PLATs were devoid of inflammation and sharply demarcated from the surrounding CLT. There is cyto-morphological overlap with papillary thyroid carcinoma (nuclear grooves and pseudo-inclusions). We conclude that PLAT is associated with CLT more frequently than any other thyroid lesion, and feel that this is more than merely a chance association. PLAT shares several cytological features with papillary carcinoma and cases have been seen where they have occurred in the same thyroid. PLAT could therefore represent an unusual variant of papillary carcinoma.

Adenoma↗
PubMed1994

Melanoma botryoides: a distinctive myxoid pattern of sino-nasal malignant melanoma.

Two primary sino-nasal melanomas are presented which were characterized by their botryoid growth pattern and myxoid stroma. These polypoid tumours contained small amounts of melanin and only focal areas of epithelioid cells. An in situ component was present in both of the tumours. Malignant melanoma should be considered when confronted by a myxoid tumour (with or without melanin) in the sino-nasal region. These tumours are widely infiltrative, and there is no evidence to suggest that they will behave any differently from conventional, non-botryoid, non-myxoid sino-nasal melanomas.

Aged↗