Search PubMed⌕ Search

Biomedical subjects

B Zbar

Publications and source records attributed to B Zbar.

266 records · Page 15Linked to original sources
PubMed1969

Tumor-specific antigens detected by inhibition of macrophage migration.

Tumor-specific antigens of a guinea pig hepatoma induced by diethylnitrosamine were detected by the inhibition of migration of specifically sensitized macrophages from capillary tubes, and by the local passive transfer of delayed skin hypersensitivity and the suppression of growth of intradermally same injected tumor.

Animals↗
PubMedDate not supplied

Loss of alleles of loci on the short arm of chromosome 3 in renal cell carcinoma.

Loss of genes at specific chromosomal loci is a characteristic of retinoblastoma, Wilms' tumour, transitional cell carcinoma of the bladder, embryonal tumours and small cell carcinoma of the lung. The significance of nonrandom gene loss in these neoplasms is that gene loss on one chromosome may uncover null mutations at corresponding loci of the homologous chromosome. Loss of specific gene products from somatic cells may be critical in the origin or evolution of certain human tumours. Clues to identification of new loci of gene loss in common adult solid tumours may be found in literature that describes chromosomal abnormalities in rare heritable cancers. Karyotypes of tumours in two families with hereditary renal carcinoma showed translocations involving the short arm of chromosome 3 (refs 10 and 11). We have examined tumours from 18 patients with non-hereditary renal cell carcinomas and found loss of alleles at loci on the short arm of chromosome 3 in all eleven of the patients who could be evaluated.

Adult↗
PubMedDate not supplied

Imaging features of hereditary papillary renal cancers.

PURPOSE: Our goal was to describe the imaging features of hereditary papillary renal cancer syndrome (HPRC), a new familial cancer syndrome. METHOD: Members of seven kindreds with HPRC comprising 78 individuals were screened with contrast-enhanced CT and abdominal US. MRI was performed in three patients. Enhancement values and doubling times of solid masses were determined from CT scans. RESULTS: Seventeen of 78 (22%) patients were affected. The HPRCs demonstrated lower enhancement (mean change in enhancement = 31 HU) than a comparable group of clear cell tumors (mean change in enhancement = 67 HU: p = 0.00001). The median tumor doubling time on serial CT was 18 months. The HPRCs were relatively hypovascular, enhanced uniformly, and grew slowly. Therefore, careful measurements of the region of interest should be obtained before and after intravenous administration of contrast medium. Though US detected only 45% of the lesions visualized on CT, it was useful in determining if lesions were cystic. Contrast-enhanced MRI demonstrated similar characteristics to contrast-enhanced CT. CONCLUSION: The tumors of patients with HPRC pose some diagnostic difficulties because they can be missed by US, are small, and enhance poorly on CT. CT is preferable to US as a screening tool because of its higher sensitivity in detecting small lesions, and when contrast media cannot be administered, MR is a suitable alternative to CT.

Abdomen↗
PubMedDate not supplied

Molecular genetic characterization of neuroendocrine lung cancer cell lines.

Small cell lung cancers express neuroendocrine (NE) cell features, while most non-SCLC tumors lack these features. We studied the cytogenetic and genetic alterations in cell lines derived from three unusual subtypes of lung cancer: including carcinoids, non-small cell lung cancers expressing NE properties (NSCLC-NE) and extrapulmonary small cell cancers (ExPuSC) and compared them with those of SCLC and NSCLC lines. Our studies included: cytogenetic studies, restriction fragment length polymorphism (RFLP) analyses with 8 probes spanning commonly deleted loci on chromosomes 3p, 13q and 17p, retinoblastoma gene product (RB) expression, and mutations in the ras and p53 genes. We also summarize previously published data on in vitro chemosensitivity patterns and MDRl gene expression. Our studies demonstrate that all three of the NE cell subtypes have their own distinctive genotypes and phenotypes, each having some similarities and dissimilarities with SCLC and NSCLC.

Aneuploidy↗
PubMedDate not supplied

Mechanism of tumorigenesis of renal carcinomas associated with the constitutional chromosome 3;8 translocation.

PURPOSE: Members of a family carrying a constitutional balanced translocation [t(3;8) (p14;q24)] have a high risk of developing multiple, bilateral clear-cell renal carcinomas. Two genetic mechanisms of carcinogenesis for this malignancy have been proposed: (1) disruption of a gene at the translocation breakpoint and (2) mutation of the von Hippel-Lindau tumor-suppressor gene at 3p25. This study further evaluates the role of the von Hippel-Lindau gene in the etiology and pathogenesis of t(3;8)-associated renal carcinomas. METHODS: Two new t(3;8)-associated renal carcinomas were tested for mutations in the von Hippel-Lindau gene by single-stranded conformational polymorphism analysis followed by direct DNA sequencing, for loss of alleles on chromosomes 3p and 8, and for methylation abnormalities in the first cloned exon of the von Hippel-Lindau gene. RESULTS: A missense mutation in the von Hippel-Lindau gene was found in one of the two t(3;8)-associated renal carcinomas. This mutation would produce a stop codon and a truncated protein. Both tumors showed a loss of alleles on the derivative 8 chromosome. When these results were combined with the results of our previous studies, two of the four t(3;8)-associated renal carcinomas, which were examined for molecular genetic changes, showed different von Hippel-Lindau somatic mutations. All renal tumors from the 3;8 translocation family showed loss of the translocated portion of chromosome 3. CONCLUSIONS: These results support a mechanism of tumorigenesis in the chromosome (3;8) translocation family that involves the loss of both copies of the von Hippel-Lindau gene.

Carcinoma, Renal Cell↗