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W M Linehan

Publications and source records attributed to W M Linehan.

240 records · Page 14Linked to original sources
PubMedDate not supplied

Molecular and genetic characterization and physical mapping of 11 new markers detecting multiallele restriction fragment length polymorphisms on the short arm of human chromosome 3.

Genetic markers with high degrees of polymorphisms are of vital importance in the construction of high resolution (2-4 cM) linkage maps of human chromosomes as specified in the short-term goals of the Human Genome Initiative. In this paper, we report on molecular and genetic characterization and physical localization of 11 new multiallele restriction fragment length polymorphism markers on human chromosome 3p. Ten of these represent three- and four-allele polymorphisms of the base substitution type probably at two adjacent restriction sites. One has been identified as a novel mini-satellite sequence comprising a variable copy number tandem repeat array of a G/T-rich 79-bp sequence. This collection of multiallele polymorphic (PIC values: 0.40-0.60) markers should prove valuable and increase the resolution power of the available chromosome 3p genetic markers.

Alleles↗
PubMedDate not supplied

MR imaging of pheochromocytomas.

Magnetic resonance imaging (MRI) of seven patients with pheochromocytomas demonstrable by CT was performed. Magnetic resonance imaging showed all primary pheochromocytomas, as well as metastatic lesions to the thorax, retroperitoneum, and liver. The ability to distinguish pheochromocytomas from surrounding structures without the need of an intravenous contrast agent and to provide direct coronal and sagittal images suggests that MRI may be useful in detecting and localizing these tumors.

Adolescent↗
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

Collecting duct carcinomas of the kidney: a comparative loss of heterozygosity study with clear cell renal cell carcinoma.

Origin of collecting duct carcinomas (CDC) of the kidney is not entirely known, although it is thought that they originate from the distal collecting duct system, whereas clear cell renal cell carcinoma (cRCC) may originate from the proximal tubular epithelium. In cRCC, the von Hippel Lindau gene (vHL) is damaged in almost 100% of cases; the frequency of vHL deletions in CDC is not known. Loss of heterozygosity (LOH) of CDC and cRCC of vHL (3p), p16 (9p), p53 (17p) and the retinoblastoma (RB) gene (13q) was studied to evaluate possible genetic differences between the two. LOH of the vHL was seen in 77.7% of cRCC and in 55% of CDC. P16 was lost in 33% of cRCC and in 50% of CDC. LOH in p53 was observed in 0/8 cases of cRCC compared to 18.7% in CDC. LOH in 13q was seen in 25% of both CDC and cRCC. The high LOH rate of the vHL gene in CDC has not been observed previously. The findings indicate that CDC and cRCC share certain genetic alterations, including frequent deletion of the vHL gene. CDC is not clearly related to cRCC but may be of heterogeneous origin.

Adenocarcinoma, Clear Cell↗