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Biomedical subjects

L M Weiss

Publications and source records attributed to L M Weiss.

At least 145 records · Page 8Linked to original sources
PubMed1996

Burkitt's lymphoma in Brazil: strong association with Epstein-Barr virus.

The incidence of Burkitt's lymphoma (BL) in Brazil is intermediate between the endemic form of equatorial Africa and the sporadic form in the United States. To characterize these lymphomas, we evaluated the clinical, morphologic, and immunohistochemical features of 24 Brazilian cases of BL. We also analyzed the cases for the presence of Epstein-Barr virus (EBV)-RNA using a highly sensitive and specific method of in situ hybridization. Most cases presented with involvement of intraabdominal organs, similar to the sporadic form of BL. EBV-RNA was detected in 17 of 24 cases (71%) in all or virtually all the tumor cells. This prevalence of EBV-positivity in our cases is intermediate between the endemic form of BL in equatorial Africa (100%) and the sporadic form in the United States (30%). These findings suggest that EBV plays an important role in the pathogenesis of BL in Brazil. This intermediate incidence of EBV infection may explain in part the differences of incidence of BL in different geographic regions.

Adolescent↗
PubMed1996

p53 mutations in Hodgkin's disease.

Although numerous studies have demonstrated increased expression of p53 protein in the Reed-Sternberg cells of Hodgkin's disease, little data exist as to whether mutations of the p53 gene is a common occurrence in this neoplasm. Using a microdissection technique coupled with PCR, single-strand conformation analysis, and DNA sequencing, we studied 23 cases of Hodgkin's disease for mutations within exons 5 to 8 of the p53 gene. We found seven mutations within six cases; six were missense mutations. An identical missense mutation was found in three cases (codon 243, methionine to isoleucine), and another identical missense mutation was found in an additional two cases (codon 204, glutamic acid to lysine). Verification of the mutations was accomplished either by direct Southern blotting of PCR-amplified p53 exon products from re-extracted DNA or by hybridization of cloned PCR-amplified p53 exon products from re-extracted DNA with a mutant-specific oligonucleotide. There was no good correlation between the presence of p53 mutations and the level of p53 protein expression, which was found to be overexpressed in all cases, the level of MDM2 protein expression, or the proliferation rate as determined by K-67 antibody. None of the cases with p53 mutation had evidence of Epstein-Barr virus within the Reed-Sternberg cells, as compared with 7 of 17 of the other cases (p < 0.06). These results suggest that p53 mutation may represent an important mechanism in the pathogenesis of Hodgkin's disease, and this mechanism may be independent of Epstein-Barr virus.

Base Sequence↗
PubMed1996

Effects of verapamil on acute murine Chagas' disease.

Continuous administration of verapamil significantly reduced the mortality rate of acute murine Trypanosoma cruzi infection (P < 0.05). The mechanistic basis for these observations was investigated. Verapamil and other calcium-channel blockers did not inhibit the growth of epimastigotes in culture. Furthermore, verapamil did not inhibit the intracellular growth of amastigotes in endothelial cells as determined by the uptake of 3H-uracil. There were no significant differences in parasitemia between infected mice that were untreated and those treated with verapamil. Twenty days postinfection infected, untreated mice had a parasitemia of 5.8 x 10(6) trypomastigotes/ml (SD +/- 2 x 10(6)), whereas infected, verapamil-treated mice had a parasitemia of 2.2 x 10(6) trypomastigotes/ml (SD +/- 0.5 x 10(6)). There was no significant difference in mortality between mice administered verapamil only for the initial 10 days of murine infection compared to those treated continuously. A 3-day delay in the initiation of verapamil administration reduced the mortality rate, but a 10-day delay did not. Propranolol (beta-adrenergic blocker), prazosin (alpha 1-adrenergic blocker), and diltiazem (another calcium-channel blocker) reduced the mortality but not significantly (P = 0.07). In biochemical studies of the beta- adrenergic signal transduction complex, we determined that verapamil and propranolol reversed the infection-associated decrease in myocardial beta- adrenergic adenylyl cyclase activity. In contrast, complementary western blot analysis revealed no significant changes in the G-proteins of the beta- adrenergic receptor complex 45 days postinfection. Therefore, these results suggest that the basis of verapamil's influence on the early critical period of infection is multifactorial and independent of a direct trypanocidal effect.

Acute Disease↗
PubMed1996

Absence of Kaposi's sarcoma-associated herpesvirus-like DNA sequences in malignant vascular tumors of the serous membranes.

Reports connect Kaposi's sarcoma-associated herpesvirus (KSHV) with various types of Kaposi's sarcoma (KS) and body-cavity-based lymphomas (primary effusion lymphomas). KSHV DNA sequences have also been detected in a few non-KS malignant vascular tumors. To determine whether KSHV is associated with malignant vascular tumors involving the body cavities, 11 primary vascular tumors of the serous membranes (4 angiosarcomas, 7 hemangioendotheliomas) were tested for KSHV sequences by polymerase chain reaction and Southern blot hybridization. The tumors were from patients who were not known to be immunocompromised. KSHV sequences were detected in the penile KS control but were absent in all 11 specimens studied. Our results were consistent with previous reports that KSHV sequences were rarely detected in non-KS vascular lesions. The results also suggested that although KSHV sequences might be present in primary effusion tumors such as primary effusion lymphoma, they might not be found in other tumors related to body cavities or to serous membranes.

Blotting, Southern↗
PubMed1995

Absence of the t(2;5) in Hodgkin's disease.

The cytogenetics of Hodgkin's disease (HD) is poorly understood. However, a t(2;5) is a common finding in CD30+ anaplastic large cell lymphoma (ALCL), a neoplasm thought by some to be closely related to HD. Recently, the t(2;5) has been cloned and found to represent fusion of the NPM gene with the ALK gene. Using Southern blot hybridization, one group has reported finding rearrangements of NPM in a proportion of cases of both ALCL and HD. In the current study, we used a highly sensitive reverse transcriptase-polymerase chain reaction methodology to analyze 34 cases of HD for the t(2;5). We were unable to find polymerase chain reaction evidence for the t(2;5) in any of the cases of HD, a result significantly different from our previous study of CD30+ non-Hodgkin's lymphomas (P < .02) including ALCL (P < .04), using identical methods. Our results do not support the hypothesis that the t(2;5) represents a common chromosomal abnormality for both HD and ALCL.

Anaplastic Lymphoma Kinase↗
PubMed1995

Concordance for Hodgkin's disease in identical twins suggesting genetic susceptibility to the young-adult form of the disease.

BACKGROUND: Relatives of young adults with Hodgkin's disease are at increased risk of Hodgkin's disease, and lines of evidence implicate both inheritance and environment. METHODS: We have identified and followed 432 sets of twins affected by Hodgkin's disease. The number of cases of Hodgkin's disease observed before the age of 50 years in the healthy monozygotic and dizygotic twins of the patients with Hodgkin's disease was compared with the number expected from national age-specific incidence rates. RESULTS: None of the 187 pairs of dizygotic twins became concordant for Hodgkin's disease, whereas 10 of the 179 pairs of monozygotic twins did; in 5 of these pairs, the second case appeared after the original ascertainment. During the observation period, 0.1 (monozygotic) and 0.1 (dizygotic) cases in the unaffected twins were expected. Monozygotic twins of patients with Hodgkin's disease thus had a greatly increased risk (standardized incidence ratio, 99; 95 percent confidence interval, 48 to 182), whereas no increase in the risk for dizygotic twins of patients with Hodgkin's was observed. CONCLUSIONS: Genetic susceptibility underlies Hodgkin's disease in young adulthood.

Adolescent↗
PubMed1995

Chromosome 11q13 amplification in head and neck squamous cell carcinoma. Association with poor prognosis.

OBJECTIVE: To determine the clinical and prognostic significance of chromosome 11q13 amplification in squamous cell carcinoma of the head and neck. DESIGN: Retrospective clinical analysis. SETTING: University and private cancer centers. PATIENTS: Fifty-six patients with pathologically confirmed head and neck squamous cell carcinoma whose tumors had been assayed for the presence or absence of chromosome 11q13 amplification. MEASUREMENTS: The degree of DNA amplification in each tumor was determined using chromosome 11q13 probes for the bcl-1 major translocation cluster, PRAD1/cyclin D1 (CCND1), the fibroblast growth factor gene HST1, EMS1, and glutathione-S-transferase-pi-1. The presence or absence of amplification in each patient was correlated with primary site, tumor stage, nodal status, presence or absence of distant metastasis, disease recurrence, time to recurrence, clinical outcome (disease status), and overall survival. RESULTS: Amplification of chromosome 11q13 was identified in 39% (22/56) of patients. Recurrent or persistent disease was identified in 82% (18/22) of cases with amplification and 50% (14/28) of nonamplified cases (P = .04). Mean time to recurrence was shorter in cases with amplification (6.2 months) than those without amplification (10.1 months) (P = .01). Eighteen patients (82%) with amplification and 10 patients (38%) without amplification died of disease or are alive with disease (P = .001). The mean follow-up period was 15.8 months for patients with amplification and 18.6 months for patients without amplification. Overall survival was significantly diminished in patients with amplification (P = .002). Amplification was not related to nodal status, distant metastases, or initial disease stage. CONCLUSIONS: Amplification of chromosome 11q13 loci may be an important biologic marker indicating poor prognosis, independent of clinical stage in head and neck squamous cell carcinoma, and it should be assessed in prospective trials to determine its utility for stratifying treatment and determining prognosis.

Adult↗
PubMed1995

Severe anemia as the presenting manifestation of giant cell arteritis.

Giant cell (temporal, cranial) arteritis (GCA) is usually confirmed in patients presenting with classic features. Those who present with atypical features often undergo prolonged evaluations until a diagnosis is established. Severe anemia as an initial manifestation of GCA has rarely been described. We describe herein 2 patients with biopsy-proven GCA who presented with severe anemia and significant weight loss, which corrected after corticosteroid therapy.

Aged↗
PubMed1995

Cyclin D1 (PRAD1, CCND1) and glutathione-S-transferase pi gene expression in head and neck squamous cell carcinoma.

Chromosome 11q13 amplification has been identified in a subset of head and neck squamous cell carcinomas (H&N SCCs). This region contains several putative oncogenes, including cyclin D1 (PRAD1, CCND1), which encodes for an important cell cycle regulatory protein, and the locus encoding for the drug-detoxifying enzyme glutathione-S-transferase-pi (GST-pi). To determine the relationship of cyclin D1 and GST-pi gene amplification to expression of the encoded proteins, the authors examined 64 H&N SCCs by both Southern blot hybridization and immunohistochemistry, using a recently described, affinity-purified, anticyclin D1 polyclonal antibody no. 19 as well as a polyclonal antibody against GST-pi. Anticyclin D1 antibody no. 19 labeled the tumor cell nuclei in 28 (44%) of the H&N SCCs, whereas cytoplasmic immunoreactivity for GST-pi was noted in 55 (86%) neoplasms. By Southern blot 24 tumors (37.5%) showed twofold to tenfold amplification of 11q13 loci; only two of these were coamplified for GST-pi. Immunopositivity with anticyclin D1 antibody no. 19 but not anti-GST-pi significantly correlated with 11q13 amplification (P < .0001). Of the 28 tumors positive with anticyclin D1 antibody no. 19, however, only 18 (64%) were amplified for 11q13, and six amplified tumors did not react with the no. 19 antibody. A strong trend was noted between anticyclin D1 antibody no. 19 reactivity and a hypopharyngeal primary site (P = .053), but no correlations were observed between immunoreactivity and cytological grade, architectural pattern, pathological stage, and disease-free or overall survival. The inconsistent association of cyclin D1 immunoreactivity with 11q13 amplification indicates that other mechanisms may exist for protein overexpression. Immunoreactivity for the GST-pi protein is prevalent in H&N SCC but is clearly unassociated with amplification. In this series, the presence or extent of cyclin D1 and GST-pi immunoreactivity was of no proven prognostic benefit in H&N SCC.

Adult↗
PubMed1995

Changes in tonsils and adenoids in children with posttransplant lymphoproliferative disorder: report of three cases with early involvement of Waldeyer's ring.

Posttransplant lymphoproliferative disorder (PTLD) is an infrequent complication of transplantation in children, and this report emphasizes the value of tonsil and adenoid biopsy in the early management of this potentially life threatening condition. In all three cases biopsy specimens of tonsils and adenoids were diagnostic of polymorphic diffuse B-cell hyperplasia (PBCH). Immunophenotyping showed no immunoglobulin (Ig) light chain restriction, although immunoglobulin heavy chain (IgH) gene rearrangement was monoclonal in two cases. Despite an absence of serological evidence for acute Epstein-Barr virus (EBV) infection, EBV was detected in all cases by semiquantitative polymerase chain reaction (PCR) for EBV DNA, by in situ hybridization for EBV mRNA (EBER), and by immunoperoxidase for EBV latent membrane protein (LMP). All three patients were treated with reduced immunosuppression and acyclovir and are well (19, 28, and 28 months' follow-up) with no recurrence. Children without previous EBV exposure may develop PTLD localized to the tonsils/adenoids, and biopsy specimens of these tissues may permit early diagnosis and clinical intervention. Despite monoclonal gene rearrangement in two cases, overall features were not indicative of malignancy. Strong association with EBV is helpful in confirming the diagnosis of PTLD and is consistent with initial presentation in the tonsils/adenoids.

Adenoids↗
PubMed1995

"Quilty" revisited: a 10-year perspective.

The goals of this study were to better define Quilty lesions, facilitating differentiation from other endocardial infiltrates; to correlate Quilty lesions with clinical parameters; and to assess whether classification into Quilty A (noninvasive lesions) and Quilty B (invasive lesions) had clinical utility. Two hundred seventeen adults who received transplants between 1981 and 1987 and 22 children who received transplants between 1981 and 1989 were studied. Allograft survival for over 1 year was the selection criterion. Clinical, angiographic, and biopsy data were reviewed up to 1992, obtaining a minimum follow up of 5 years for adults and 3 years for children. All 7,439 endomyocardial biopsy cases were allotted an International Society for Heart and Lung Transplantation (ISHLT) grade for rejection, and Quilty was classified as Quilty A or B. Quilty was correlated with transplant recipient age and gender, cytomegalovirus and Epstein-Barr virus (EBV) infection, treatment protocols, allograft rejection, graft vascular disease (GVD), and lymphoma. Immunohistochemistry was performed to determine Quilty cell composition. Quilty incidence was 49.77% in adults and 68.18% in children, and did not appear to be influenced by cyclosporine dosage. Quilty showed no gender variation nor association with cytomegalovirus (CMV) or EBV infection or lymphoma. A total of 74.04% of adults developed Quilty within the first year posttransplant and 81.48% had multiple Quilty-positive biopsies. One hundred eight of 217 Quilty-positive adults had 456 Quilty-positive endomyocardial biopsies, 82.24% of which were associated with an ISHLT grade of 0 or I, and only 12.28% being associated with a grade III rejection. Histological division into Quilty A and Quilty B did not appear to have clinical significance. Graft vascular disease appears to have decreased significantly more in Quilty-positive patients. Although our findings in children were similar to those in the adults, we were unable to draw definite conclusions, the number of children being too small to permit valid statistical correlations.

Adolescent↗
PubMed1995

Frequent presence of the Epstein-Barr virus in inflammatory pseudotumor.

Inflammatory pseudotumor is a presumably nonneoplastic, hematopoietic, and spindled fibrous proliferation that may occur at a variety of anatomic sites. The origin of these proliferations is generally unknown. To evaluate the role of the Epstein-Barr virus (EBV) in inflammatory pseudotumor, 18 specimens from 17 patients were studied by in situ hybridization for EBV ribonucleic acid (RNA), and the morphological and immunologic characteristics of the infected cells were evaluated. These specimens included 10 lymph nodes, six splenic masses, and two hepatic masses. Overall, EBV RNA was detected in 41.2% (seven of 18) of the cases. These included two of 10 (20%) lymph nodes, four of six (66.7%) splenic pseudotumors, and one of two (50%) hepatic lesions. The degree of EBV infection was significantly greater within the tumors in comparison with the surrounding, uninvolved tissue. Two morphologically different EBV-positive cell types, spindled and round cells, were evident, and the infected cell type differed significantly when the nodal and extranodal cases were compared. All of the positive extranodal cases shown, numerous EBV-positive spindled cells, whereas no positive spindle cells (only positive round cells, morphologically consistent with lymphocytes) were noted in the two EBV-positive lymph node pseudotumors. Double-labeling immunohistochemical and in situ hybridization studies in some cases identified rare EBV-positive B cells and rare EBV positive T cells in four and three cases, respectively. Most EBV-positive cells in all cases failed to immunoreact with any B- or T-cell markers. Three of five cases studied, however, did show a subpopulation of smooth muscle actin/EBV-positive spindled cells, five of seven cases showed vimentin/EBV-positive spindled cells, and one of four cases had EBV-positive spindled cells that immunoreacted as follicular dendritic cells. These results suggest that EBV plays a role in a significant number of cases of inflammatory pseudotumor with differences in the incidence of EBV infection and the cell type (spindled vs round cell) infected when extranodal and nodal cases are compared, suggesting a difference in pathogenesis. The cell type infected in extranodal cases seemed to be of mesenchymal origin but could not be clearly defined.

Adolescent↗
PubMed1995

The role of Epstein-Barr virus in lymphoepithelioma-like carcinomas.

Epstein-Barr virus (EBV) has been implicated in the pathogenesis of a variety of lymphoproliferative disorders and several epithelial neoplasms, including undifferentiated nasopharyngeal carcinoma (UNPC; lymphoepithelioma). Lymphoepithelioma-like carcinomas (LEC) are tumors with morphologic features identical to UNPC that occur outside the nasopharynx. To determine whether EBV is associated with LEC, the authors conducted a comprehensive literature review of all pathologically documented LEC reported to date in the English literature. In summary, EBV is associated consistently with LEC from only four anatomic sites: stomach, salivary gland, lung, and thymus. Racial and/or geographic factors influence the association of EBV with LEC in some of these organs. Specifically, the association of EBV with LEC of the salivary gland and lung is restricted to Asian patients, whereas the association of EBV with gastric and thymic LEC is independent of race. The presence or absence of EBV in LEC does not appear to be prognotically important in those cases studies to date.

Breast Neoplasms↗
PubMed1995

Adult renal epithelial neoplasms.

The consideration of adult renal epithelial neoplasms is no longer limited to renal adenocarcinoma, but also includes oncocytoma, chromophobe carcinoma, renal papillary neoplasms, collecting duct carcinoma, and neuroendocrine tumors. The recent application of classical and molecular cytogenetic techniques, particularly the studies of Kovacs and colleagues, has provided a biologic basis for this new classification. This review discusses the clinical and pathologic characteristics of these entities, with attention to differential diagnosis. Prognostic factors in renal adenocarcinoma are also discussed.

Adenocarcinoma↗
PubMed1995

Adrenal cortical tumors clinically mimicking pheochromocytoma.

The authors report five patients with adrenal cortical tumors in whom the preoperative diagnosis of pheochromocytoma was made. All patients had biochemical evidence of elevated catecholamine secretion in serum or urine. Clinically, two patients presented with symptoms suggestive of pheochromocytoma, and one patient had systemic hypertension that resolved following surgical excision of the tumor. Histologically, the findings were typical of adrenal cortical tumors: two adrenal cortical carcinomas and three adrenal cortical adenomas. Nevertheless, the immunohistochemical studies showed evidence of neuroendocrine differentiation in four tumors. Three tumors were positive for neuron-specific enolase and synaptophysin and a fourth tumor was positive for synaptophysin only. All neoplasms were negative for chromogranin. Electron microscopic studies in three tumors showed abundant endoplasmic reticulum and tubulovesicular cristae consistent with adrenal cortical cell origin. Neurosecretory granules, 150-300 mu in diameter, were found in one tumor. This current series of patients provides evidence that adrenal cortical neoplasms may be associated with clinical findings that simulate pheochromocytoma (so-called pseudo-pheochromocytoma). These clinical findings may be mediated by the presence of neuroendocrine features in these tumors.

Adrenal Cortex Neoplasms↗