Detection of frequent allelic loss on proximal chromosome 17q in sporadic breast carcinoma using microsatellite length polymorphisms.

Analyses of losses of heterozygosity and linkage studies have implicated a gene(s) on chromosome 17q in the genesis of sporadic and early-onset familial breast carcinomas, respectively. To define the critical region of 17q, we examined DNAs from a series of 20 sporadic breast carcinomas and corresponding blood samples for allelic losses of chromosome 17q using microsatellite length polymorphisms. With these highly informative markers (average heterozygosity, 0.73), we observed frequent deletions of 17q at several loci. We found that D17S250 was deleted in 50% (7 of 14), THRA1 in 79% (11 of 14), D17S579 in 59% (11 of 19), NME1 in 29% (5 of 17), MPO in 36% (4 of 11), and GH in 25% (4 of 16) in the tumor set examined. A common region of deletion was found that was flanked by D17S250 to D15S579. These markers have recently been localized to a 6-cM interval of proximal chromosome 17q in bands 17q11.2-q21 and map within the region of the early-onset familial breast cancer locus, implying that the same gene or genes may be involved in both sporadic and familial breast tumors. Thyroid hormone receptor alpha and retinoic acid receptor alpha are two potential candidate genes in this region.     

The role of cyclic nucleotides in atrial natriuretic peptide-mediated inhibition of aldosterone secretion

Using freshly isolated bovine adrenal glomerulosa cells we examined the inhibitory effect of atrial natriuretic peptide (ANP) on aldosterone secretion stimulated by agonists that use either the Ca2+-phosphoinositide or cAMP messenger system. In a continuous perifusion system, angiotensin II (AII) induces a prompt initial rise in aldosterone secretion, followed by a sustained secretory response. Both phases of secretion are rapidly and independently inhibited by ANP. The role of two cyclic nucleotides, cGMP and cAMP, as mediators of this ANP-induced inhibition was examined. The effect of 8-bromo-cGMP (1-100 microM) or (Bu)2cGMP (1-50 microM) on the AII-stimulated rate of secretion was studied in a perifusion system. Either analog, whether added early or late, maximally inhibited by 20-30% only the late or sustained phase of aldosterone secretion. The effect of ANP on cellular cAMP content was examined in a static incubation system. Although ANP caused a reduction in the cAMP content of cells stimulated with either AII or ACTH, it had little or no effect on the cAMP levels in cells stimulated with carbachol. In AII- and ACTH-stimulated cells, the relationship between reduced cAMP content and reduced secretion was explored. In the AII-stimulated cell inhibited by ANP, simple restoration of cAMP content with forskolin did not restore the secretory rate. Pertussis toxin treatment blocked the inhibitory effect of ANP on cAMP content, but did not block its inhibition of secretion. In the ACTH-stimulated cell, reversal of the ANP-induced reduction of cAMP with forskolin, partially restored the stimulated rate of secretion, although restoration of cAMP with a 10-fold higher dose of ACTH did not restore the stimulated rate of secretion in the presence of ANP. These results imply that both the ANP-induced rise in cGMP and the ANP-induced decrease in cellular cAMP content may contribute to the inhibition of steroidogenesis. However, these inhibitory messages do not induce either the magnitude or the temporal pattern of inhibition induced by ANP. Thus, in the adrenal multiple messenger systems may underlie the action of ANP.     

High-specificity in-situ hybridization. Methods and application.

We describe a technique of in-situ hybridization using oligonucleotide probes employing the expression of immunoglobulin VH genes as a model. Optimal conditions for hybridization with the 35S-labeled oligonucleotide probes were established with monoclonal B-cell lines that express VH genes of known nucleic acid sequence. The range of sensitivity and specificity achieved with this technique is documented. Under conditions of high stringency, this method can detect the expression of highly related VH hypervariable regions.     

Gene expression profiles of serous, endometrioid, and clear cell subtypes of ovarian and endometrial cancer.

PURPOSE: The presence of similar histologic subtypes of epithelial ovarian and endometrial cancers has long been noted, although the relevance of this finding to pathogenesis and clinical management is unclear. Despite similar clinical characteristics, histologic subtypes of cancers of the ovary and endometrium are treated according to organ of origin. This study compares the gene expression profiles of analogous histologic subtypes of cancers of the ovary and endometrium using the same genomic platform to determine the similarities and differences between these tumors. EXPERIMENTAL DESIGN: Gene expression profiles of 75 cancers (endometrioid, serous, and clear cell) of the ovary and endometrium, five renal clear cell cancers, and seven normal epithelial brushings were determined using a 11,000-element cDNA array. All images were analyzed using BRB ArrayTools. Validation was done using real-time PCR on select genes and immunohistochemical staining. RESULTS: Comparison across endometrial and ovarian cancers and serous and endometrioid tumors showed expression patterns reflecting their organ of origin. Clear cell tumors, however, showed remarkably similar expression patterns regardless of their origin, even when compared with renal clear cell samples. A set of 43 genes was common to comparisons of each of the three histologic subtypes of ovarian cancer with normal ovarian surface epithelium. CONCLUSIONS: The comparison of the gene expression profiles of endometrioid and serous subtypes of ovarian and endometrial cancer are largely unique to the combination of a particular subtype in a specific organ. In contrast, clear cell cancers show a remarkable similarity in gene expression profiles across organs (including kidney) and could not be statistically distinguished.     

Scale-up of Adhesive Transdermal Drug Delivery Systems

Pharmaceutical Research -     

Chronic Inhalation Toxicity and Carcinogenicity Testing of Respirable Fibrous Particles

On May 8–10, 1995, a workshop on chronic inhalation toxicity and carcinogenicity testing of respirable fibrous particles was held in Chapel Hill, North Carolina. The workshop was sponsored by the Office of Pollution Prevention and Toxics, U.S. Environmental Protection Agency (EPA), in collaboration with the National Institute of Environmental Health Sciences (NIEHS), the National Institute for Occupational Safety and Health (NIOSH), and the Occupational Safety and Health Administration (OSHA). The goal of the workshop was to obtain input from the scientific community on a number of issues related to fiber testing. Major issues for discussion were: (i) the optimal design and conduct of studies of the health effects of chronic inhalation exposure of animals to fibers; (ii) preliminary studies which would be useful guides in designing the chronic exposure study; (iii) mechanistic studies which would be important adjuncts to the chronic exposure study to enable better interpretation of study results and extrapolation of potential effects in exposed humans; and (iv) available screening tests which can be used to develop a minimum data set for (a) making decisions about the potential health hazard of the fibers and (b) prioritizing the need for further testing in a chronic inhalation study. After extensive discussion and debate of the workshop issues, the general consensus of the expert panel is that chronic inhalation studies of fibers in the rat are the most appropriate tests for predicting inhalation hazard and risk of fibers to humans. A number of guidances specific for the design and conduct of prechronic and chronic inhalation studies of fibers in rodents were recommended. For instance, it was recommended that along with other information (decrease in body weight, systemic toxicity, etc.), data should be obtained on lung burdens and bronchoalveolar lavage fluid analysis to assist in establishing the chronic exposure levels. Lung burden data are also important for quantifying aspects of risk assessment related to dosimetric adjustments before extrapolation. Although mechanistic studies are not recommended as part of the standard chronic inhalation studies, the expert panel stressed the need for obtaining mechanistic information as far as possible during the course of subchronic or chronic inhalation studies. At present, no single assay and battery of short-term assays can predict the outcome of a chronic inhalation bioassay with respect to carcinogenic effects. Meanwhile, several short-termin vitroandin vivostudies that may be useful to assess the relative potential of fibrous substances to cause lung toxicity/carcinogenicity have been identified.