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Sydney Finkelstein

Publications and source records attributed to Sydney Finkelstein.

28 records · Page 2Linked to original sources
PubMed2003

Viral regulatory region sequence variations in kidney tissue obtained from patients with BK virus nephropathy.

BACKGROUND: The polyomavirus genome contains a noncoding control region (NCCR), which is believed to contain the enhancer elements that are important activators of viral transcription. We hypothesized that DNA sequence variations in this region play a role in the pathogenesis of BK virus allograft nephropathy (BKVAN). METHODS: Tissue sections were prepared from 26 paraffin-embedded biopsies with BKVAN obtained from 15 patients. The sections were lysed in a proteinase K buffer and subjected to DNA sequencing using Big Dye cycle sequencing reactions run on an automated DNA sequencer (ABI 310). NCCR anatomy was compared to the genomic sequence of archetype BKV strain WW. RESULTS: Twelve putative transcription factor binding sites showed nucleotide substitutions, deletions, or duplications in at least one of the biopsies studied. Changes were most commonly found in binding sites for granulocyte/macrophage stimulating factor promoter (24/26 biopsies) and nuclear factor-I (NF-I) transcription factor (21/22 biopsies). Less frequent changes were seen at other binding sites, including T antigen (3/22 biopsies) and the cytomegalovirus immediate early (CMV IE-1) promoter (3/22 biopsies). Five biopsies showed complex rearrangements reminiscent of those described in JC virus-associated progressive multifocal leukoencephalopathy. CONCLUSION: The regulatory region of BKV shows sequence heterogeneity in biopsy tissue with viral nephropathy. Sequence variations frequently affect putative transcription factor binding sites, with potential implications for promoter activity related to genes important in viral replication. Architectural rearrangements were found in some cases but did not appear to be a prerequisite for the pathogenesis of BKVAN.

BK Virus↗
PubMed2003

A novel microdissection and genotyping of follicular-derived thyroid tumors to predict aggressiveness.

Distinguishing thyroid follicular adenoma from minimally invasive or encapsulated angioinvasive carcinoma can be diagnostically challenging. In some cases, tumors are distorted, fragmented, or stripped of their capsule, and a definitive diagnosis becomes nearly impossible. In other cases, the foci of capsular and/or vascular invasion are subtle, thus making the diagnosis of carcinoma difficult. We developed a microdissection genotyping assay for assessing a panel of tumor-suppressor genes for loss of heterozygosity mutations. The frequency of allelic loss (FAL) in follicular-derived neoplasms correlates with the histologic aggressiveness of the tumor. Furthermore, we calculated the amount of genetic heterogeneity within each tumor, as a second important measure of a tumor's ability for clonal expansion and a surrogate marker for its malignant potential. The follicular adenomas had a low FAL (average 9%) and low intratumoral heterogeneity (5% variability). The minimally invasive and encapsulated angioinvasive carcinomas had an intermediate FAL (average 30%) and intermediate intratumoral heterogeneity (10% variability). The widely invasive carcinomas had a high FAL (average 53%) and high intratumoral heterogeneity (24% variability). Although a larger retrospective study is needed to correlate genotyping studies with patient outcome and prognosis, our results indicate that performing a mutational genotyping assay can stratify tumors into the histologically well-defined categories of adenomas, minimally invasive/angioinvasive carcinomas, and widely invasive follicular carcinomas.

Adenoma↗
PubMed2002

Quantitation of viral DNA in renal allograft tissue from patients with BK virus nephropathy.

BACKGROUND: BK virus (BKV) allograft nephropathy (BKVAN) is a complication in renal transplantation recipients. Histopathology is the gold standard for diagnosis. Quantitative polymerase chain reaction (PCR) assay for renal biopsy has not been evaluated as a diagnostic test. Determination of renal BKV load may identify patients at risk for disease before histologic nephropathy. METHODS: Quantitative PCR assay for BKV DNA was performed in 28 biopsies of patients with BKVAN; 50 biopsies were performed before a diagnosis of BKVAN, and 126 control biopsies were from patients without a history of BKVAN. RESULTS: BKV DNA was present in 19 of 50 (38%) biopsies performed 1 to 164 weeks before diagnosis of BKVAN. The viral load (mean 216 copies/cell) was lower than in biopsies of patients with BKVAN (mean 6063 viral copies/cell, <0.05). In 10 of 127 (7.8%) control biopsies, a low level of BKV DNA (mean 3.8 copies/cell) was found in three biopsies from chronic allograft nephropathy patients; two biopsies with acute rejection; four biopsies with borderline change; and one biopsy with cytomegalovirus nephritis. CONCLUSION: BKV load exceeding 59 copies per cell identified all cases of BKVAN. The diagnostic sensitivity, specificity, positive predictive value, and negative predictive value of quantitative PCR were 100%, 92.1%, 73.6%, and 100%, respectively. Lower levels of BKV DNA were identified in biopsies performed before viral nephropathy development. Future research will determine if earlier recognition of at-risk patients allows application of antiviral strategies to improve graft outcome.

BK Virus↗
PubMed2002

DNA sequencing of viral capsid protein VP-1 region in patients with BK virus interstitial nephritis.

BACKGROUND: Mutations in the viral capsid protein VP-1 region are associated with increased pathogenicity of polyomavirus in experimental systems. This study sought to determine whether analogous viral genetic changes occur in human BK virus (BKV) interstitial nephritis (ISN). METHODS: PCR was used to amplify a 94-bp nucleotide sequence of the viral capsid protein VP-1 region (positions 1740-1833, Dun numbering) in 49 biopsies obtained from 24 patients with BKV-ISN. DNA sequencing was performed by the dideoxy method. RESULT: The VP-1 region was highly polymorphic and 22 "hot spots" of sequence variability were noted. Genotypes I, II, and IV were assigned to 13, 1, and 5 cases, respectively, but 5 cases could not be unambiguously classified due to sequence heterogeneity at sites used to discriminate between genotypes. Even in cases where genotypes could be assigned, only 5 biopsies showed complete sequence identity with published genotype sequences. Sequential biopsies showed temporal changes in one or more nucleotides in all patients with multiple samples. In one patient, the initial biopsy showed viral genotype 1, although subsequent biopsies showed complex genetic patterns, including a biopsy consistent with viral genotype IV. CONCLUSIONS: Many viral strains associated with BKV-ISN are difficult to classify and possibly distinct from those described in kidney transplant recipients without BKV-ISN. VP-1 sequences undergo continual modification as patients are followed in time. This genetic instability could conceivably have implications for evasion of host immunity and development of resistance to antiviral drugs.

BK Virus↗
PubMed2002

Human non-small cell lung tumors and cells derived from normal lung express both estrogen receptor alpha and beta and show biological responses to estrogen.

Lung cancer is becoming increasingly common in women and in the United States accounts for more female cancer deaths annually than breast cancer. Many epidemiological studies have provided evidence that women are more susceptible than men to the adverse effects of tobacco smoke. These observations suggest the possible role of estrogens in lung carcinogenesis. We report here the expression of mRNA for estrogen receptor alpha (ERalpha) and beta (ERbeta) in cultured human non-small cell lung cancer cells, cultured lung fibroblasts, and primary cultures of normal bronchial epithelium. Western analysis of ERalpha suggested that the main protein expressed in lung tumor cells is a variant, probably attributable to alternative splicing. Protein for ERbeta was found to be a mixture of full-length as well as alternatively spliced variants. beta-Estradiol produced a proliferative response in vitro in both normal lung fibroblasts and cultured non-small cell lung tumor cells. This effect was also observed in vivo. In this regard, beta-estradiol stimulated growth of the non-small cell lung tumor line, H23, grown as tumor xenografts in SCID mice. This effect was blocked by fluvestrant (ICI 182,780). In paraffin sections of non-small cell lung tumors, ERbeta immunoreactivity was localized to the nucleus, whereas ERalpha immunoreactivity was mainly localized to the cytoplasm, suggesting that both nuclear and cytoplasmic signaling may be involved in estrogenic responses in the lung. To show that the ERs found in the lung are functional, we demonstrated that beta-estradiol stimulated transcription of an estrogen response element-luciferase construct transfected in non-small cell lung tumor cell lines. Antiestrogens blocked this effect. Treatment of lung fibroblasts with beta-estradiol also increased secretion of hepatocyte growth factor by 2-fold. These results suggest that estrogen signaling plays a biological role in both the epithelium and the mesenchyme in the lung and that estrogens could potentially promote lung cancer, either through direct actions on preneoplastic or neoplastic cells or through indirect actions on lung fibroblasts. Additionally, it is possible that antiestrogens may have therapeutic value to treat or prevent lung cancer.

Animals↗
PubMed2002

Gene expression analysis of prostate cancers.

Prostate cancer is a biologically heterogeneous disease with considerable variation in clinical aggressiveness. The behavior of prostate cancer can be considered a direct or indirect result of aberrant alterations of gene expression in prostate epithelial cells. Identification of the patterns of gene-expression alterations that are related to the aggressiveness of prostate cancers will greatly assist the development of tools for early detection of prostate cancers with poor clinical outcome and identification of targets for future therapeutic intervention. To detect the patterns of gene-expression alterations of prostate cancers, we performed a comprehensive gene-expression analysis on 30 prostate tissues of various levels of invasiveness (ranging from those confined to the organ to distant metastases) and Gleason grades (combined scores 4-9), using the Affymetrix chip set Hu35k (A-D) and U95a. Following three sequential selection screens, we identified 84 largely novel genes and expressed sequence tag (EST) sequences whose expression levels were altered significantly in prostate cancer samples compared with control normal tissues. In addition, the expression levels of a group of 12 genes and EST sequences was found to be altered significantly in aggressive type of prostate cancers but not in organ-confined prostate cancers. Cluster analysis using the 84-gene list showed that the highly aggressive prostate cancers contained gene-expression patterns that were distinct from organ-confined prostate cancers.

Cluster Analysis↗
PubMed2002

Risk assignment in childhood brain tumors: the emerging role of molecular and biologic classification.

Brain tumors as a group are the most common solid tumors of childhood and currently have the highest mortality rate. A major emphasis has historically been placed on stratifying therapy for these tumors based on histologic and clinical prognostic factors. However, with the increasing application of molecular approaches to refine the categorization of these tumors, it has become apparent that histologically comparable lesions may exhibit diverse patterns of gene expression and genomic alterations, which may correspond with important prognostic distinctions. This paper summarizes these observations and discusses how they are being applied in a preliminary fashion as a foundation for risk-adapted stratification of childhood brain tumor therapy.

Biomarkers, Tumor↗
PubMed2002

Loss of heterozygosity mutations of tumor suppressor genes in cytologically atypical areas in chronic lymphocytic thyroiditis.

The relationship between chronic lymphocytic thyroiditis (CLT) and papillary thyroid carcinoma (PTC) is a subject of controversy. Some investigators suggest a causal relationship, whereas others regard the two as only a coincidental occurrence. An additional complicating factor is the presence of atypical nuclei frequently found within lymphoid infiltrates in CLT, which resemble those in PTC. The finding of the RET-PTC translocations in CLT has been reported by two independent groups of investigators, suggesting that the areas of nuclear atypia in CLT are neoplastic rather than reactive. In the present study, we report additional molecular findings that support the hypothesis that the atypical nuclear changes in CLT may be preneoplastic or neoplastic. We microdissected small areas with atypical nuclei in glands with CLT and observed loss-of-heterozygosity mutations of tumor suppressor genes. These genetic mutations are evidence of clonal preneoplastic or neoplastic changes in the follicular cells of CLT. The clinical malignant potential of these minute foci is likely to be very small but remains to be determined.

Carcinoma, Papillary↗
PubMed2002

Multifaceted resistance of gliomas to temozolomide.

PURPOSE AND EXPERIMENTAL DESIGN: The contributions of O6-methylguanine-DNA-methyltransferase(MGMT), p53 status, mismatch repair, and apoptotic response to the resistance of glial tumors to temozolomide (TMZ) were tested using seven established human glial tumor cell lines in culture and xenografts in athymic mice. RESULTS: Resistance to TMZ was only marginally dependent on MGMT activity, because subtoxic doses of TMZ easily eliminated MGMT reserves for at least 18 h after treatment. Resistance to TMZ varied most notably with the p53 status of the tumor. Tumors with wild-type (wt) p53 and a functional p53 response to DNA damage (SWB40 and SWB61) were most sensitive. The p21-related cell cycle arrest was intimately linked to TMZ toxicity because tumors with wt p53 but lacking a robust increase in p21 protein level (D-54) were resistant to TMZ. In contrast, tumors with a dysfunctional p53 cycle and a weak cell cycle response to DNA damage (SWB39 and SWB77) were extremely unresponsive to treatment even with the aid of MGMT inactivators. Notable exceptions to the above were observed with the p53 mutated tumors SWB33 and SWB95, which were arrested by TMZ in G1-S and consequently underwent apoptosis despite their failure to express p21. CONCLUSIONS: By testing a limited number of glial tumors in cell culture and also as xenografts, we have shown that mobilization of the p53 in response to TMZ damage is likely to induce a cell cycle arrest and apoptosis in glial tumors. Additional pathways linking cell cycle arrest and apoptosis contribute to the efficacy of TMZ against p53 mutated glial tumors. The unusual resistance of tumors, of which the cell cycle was not arrested in response to TMZ treatment, was associated with allelic losses during regrowth of treated tumors. Nevertheless such resistance was not related to dysfunctional mismatch repair.

Alleles↗