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Biomedical subjects

R Lance

Publications and source records attributed to R Lance.

6 recordsLinked to original sources
PubMed2001

Regulation of proliferation of prostate epithelial cells by 1,25-dihydroxyvitamin D3 is accompanied by an increase in insulin-like growth factor binding protein-3.

The biologically active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) has been shown to regulate the proliferation of human prostate epithelial cell lines. Since the insulin-like growth factor (IGF) system is involved in the transformation process of epithelial cells, the following study was undertaken to determine if the IGF system, in particular IGF binding protein-3 (IGFBP-3), is altered by 1,25-(OH)2D3 in normal prostate epithelial cells as part of a mechanism for inhibition of transformation. Two cell systems were used in this study: (1) primary cultures of benign human prostate epithelial cells (PECs) and (2) an SV40-T immortalized prostate epithelial cell line (P153) that is non-tumorigenic. 1,25-(OH)2D3 was added to parallel sets of PECs and P153 cells in addition to the presence or absence of IGF-I or des(1-3)IGF-I. Treatment with 1,25-(OH)2D3 resulted in significant growth inhibition of both PECs and P153 cells. Furthermore, 1,25-(OH)2D3 inhibited IGF-induced proliferation, but this was partially reversed by high concentrations of IGF-I. Western ligand blots of condition media demonstrated a significant increase in IGFBP-3; likewise Northern blots demonstrated an increase in mRNA for IGFBP-3. Proliferation assays using an antibody designed to block the IGF-independent effects of IGFBP-3 failed to reverse the inhibitory effect of 1,25-(OH)2D3. Thus, IGFBP-3 acts in an IGF-dependent manner to inhibit cell growth of benign prostate epithelial cells.

Calcitriol↗
PubMed2000

POU genes in metazoans: homologs in sea anemones, snails, and earthworms.

Previously undescribed POU genes were detected in several invertebrate phyla using redundant primers in a polymerase chain reaction (PCR) that targeted highly conserved sequences encoding known POU-domains. A class IV gene and a gene tentatively assigned to class VI were identified in sea anemones (Condylactis), two distinct class III genes were identified in snails (Biomphalaria), and a single class IV gene was identified in earthworms (Lumbricus). The identification of POU genes in cnidarians, mollusks, and annelids completes a survey of the major metozoan phyla. As POU genes exist in all of these organisms, they appear to be a fundamental characteristic of the metazoan lineage, and may have played a major role in the diversification of these organisms.

Amino Acid Sequence↗
PubMed1998

The association between telomerase, p53, and clinical staging in colorectal cancer.

BACKGROUND: A proposed etiology of tumor activation involves p53 mutations while telomerase may serve as a key enzyme for maintenance of tumor cell proliferation. METHODS: Telomerase activity levels were measured in colorectal adenocarcinomas and corresponding normal tissue using a modified telomeric repeat amplification protocol, and p53 mutations were identified using immunohistochemical staining. Results were compared with staging data using regression analysis. RESULTS: Telomerase activity was present in 23 of 23 (100%) of the tumors and only 2 (9%) of normal specimens (P <0.0001). The p53 mutations were present in 18 of 23 (78%) of the tumors. No significant correlation between p53 mutations, telomerase activity levels, and staging was found. CONCLUSIONS: Telomerase activity in 100% of the tumors suggests telomerase activation is a universal event in colorectal tumor progression; however, telomerase activity appears to be independent of p53 mutations and clinical staging.

Adenocarcinoma↗
PubMed1995

Oral trazodone as empirical therapy for erectile dysfunction: a retrospective review.

OBJECTIVES: Anecdotal reports of increased libido and sexual function in patients taking trazodone have led to its empirical use in patients with erectile dysfunction. A retrospective review of patient-reported responses to trazodone was performed to outline the efficacy and side-effect profile of this agent. METHODS: Between 1989 and 1994, 182 patients were placed on oral trazodone as empirical therapy for erectile dysfunction. Patients ranged in age from 26 to 85 years, with a mean of 60 years. Patients were evaluated before receiving trazodone with a thorough medical history and physical examination. Known risk factors for erectile dysfunction were assigned based on historical information and the findings of the examination. Patients received trazodone for at least 2 consecutive months, with daily doses starting at 25 mg. RESULTS: One hundred twenty-seven patients were available for follow-up by a standardized questionnaire regarding perceived improvement in erectile function, sexual function, and side effects. In patients less than 60 years of age, with no known risk factors for erectile dysfunction, 21 of 27 (78%) showed significant improvement in erectile ability. Smokers and patients older than 60 years with a history of significant peripheral vascular disease responded poorly to trazodone therapy. The duration of erectile dysfunction was inversely related to a response to trazodone. Of patients with a duration of impotence less than 12 months, 48% reported a positive response. Only 16% of patients with duration of erectile dysfunction greater than 60 months reported improvement in erections and sexual function. Trazodone was well tolerated by this population, with 62% reporting no side effects. CONCLUSIONS: Despite the limitations of a nonrandomized, retrospective study, trazodone appears to benefit younger patients with erectile dysfunction with few known risk factors. A prospective, placebo-controlled trial is needed to confirm the observations of this pilot study.

Administration, Oral↗