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Biomedical subjects

M W Frohlich

Publications and source records attributed to M W Frohlich.

10 recordsLinked to original sources
PubMed2000

Prospective trial of the herbal supplement PC-SPES in patients with progressive prostate cancer.

PURPOSE: PC-SPES is an herbal supplement for which there are anecdotal reports of anti-prostate cancer activity. This phase II study was undertaken to assess the efficacy and toxicity of PC-SPES in prostate cancer patients. PATIENTS AND METHODS: Thirty-three patients with androgen-dependent prostate cancer (ADPCa) and 37 patients with androgen-independent prostate cancer (AIPCa) were treated with PC-SPES at a dose of nine capsules daily. Clinical outcome was assessed with serial serum prostate-specific androgen (PSA) level measurement and imaging studies. RESULTS: One hundred percent of ADPCa patients experienced a PSA decline of >/= 80%, with a median duration of 57+ weeks. No patient has developed PSA progression. Thirty-one patients (97%) had declines of testosterone to the anorchid range. Two ADPCa patients had positive bone scans; both improved. One patient with a bladder mass measurable on computed tomography scan experienced disappearance of this mass. Nineteen (54%) of 35 AIPCa patients had a PSA decline of >/= 50%, including eight (50%) of 16 patients who had received prior ketoconazole therapy. Median time to PSA progression was 16 weeks (range, 2 to 69+ weeks). Of 25 patients with positive bone scans, two had improvement, seven had stable disease, 11 had progressive disease, and five did not have a repeat bone scan because of PSA progression. Severe toxicities included thromboembolic events (n = 3) and allergic reactions (n = 3). Other frequent toxicities included gynecomastia/gynecodynia, leg cramps, and grade 1 or 2 diarrhea. CONCLUSION: PC-SPES seems to have activity in the treatment of both ADPCa and AIPCa and has acceptable toxicity. Further study is required to determine whether its effects exceed those expected with estrogen therapy.

Adenocarcinoma↗
PubMed2000

Wilkinson support calculated with exact probabilities: an example using Floricaula/LEAFY amino acid sequences that compares three hypotheses involving gene gain/loss in seed plants.

This paper describes a method for quantifying the extent to which a character supports a hypothesized monophyletic group. The basic idea was first proposed by Wilkinson in 1998; hence, we call it Wilkinson support. A character provides Wilkinson support if it could have changed state on the branch leading to the hypothesized monophyletic group without requiring any extra steps in an evolutionary tree. We describe a method to determine the exact probability that a character would provide Wilkinson support for a random group of the same size as the hypothesized monophyletic group. A character's weight is defined as the negative natural log of this probability. The sum over all characters of these weights in a data set is a measure of total weighted support. We exemplify this method using 30 Floricaula/LEAFY amino acid sequences. One copy of this gene occurs in angiosperms, but two copies occur in the other four seed plant groups. Angiosperms could have been primitively single-copy or could have lost either of the two paralogs. These possibilities correspond to three hypotheses of monophyly. We use total weighted Wilkinson support to evaluate these three hypotheses, and all three are shown to be significantly different from random as individual hypothesized monophyletic groups. Comparing these three hypotheses for total weighted support reveals that one has much more support than do the other two. This hypothesis favors the "mostly-male" theory of flowering-plant origins.

Algorithms↗
PubMed1999

MADS about Gnetales.

Explore the source record for details and available documents.

Biological Evolution↗
PubMed1998

Stage II nonseminomatous testis cancer: the roles of primary and adjuvant chemotherapy.

Historically, a retroperitoneal lymph node dissection (RPLND) has been the primary treatment of stage II nonseminomatous germ cell tumor (NSGCT) patients, whereas chemotherapy has been used in the adjuvant setting. Increasing evidence of the efficacy of chemotherapy has led to additional treatment possibilities for stage II patients. Both chemotherapy and RPLND have a role in the primary therapy of stage II NSGCT, and both modalities can be used as secondary adjunctive therapy. Management of these patients now requires a renewed emphasis on risk stratification and on the integration of patient preferences into the management algorithm.

Antineoplastic Agents↗
PubMed1990

PATHMASTER: modelling differential diagnosis as "dynamic competition" between systematic analysis and disease-directed deduction.

PATHMASTER is an expert system under development to assist in teaching histopathologic differential diagnosis. The system incorporates two "orthogonal" representations of the knowledge required to perform differential diagnosis. One representation groups histopathologic features around the anatomic structures of liver tissue, the second representation groups the features around the diseases in which they occur. Using these two representations, PATHMASTER models the process of diagnosis as a "dynamic competition" between systematic analysis and disease-directed deduction. By varying two parameters of PATHMASTER's underlying mathematical model, the interplay between these factors can be varied.

Algorithms↗
PubMed1987

Evidence for arginine as the endogenous precursor of necines in heliotropium.

In pyrrolizidine alkaloid-bearing Heliotropium angiospermum and H. indicum shoots exposed, in the light, to (14)C-labeled CO(2) for 44 hours, the incorporation of (14)C into 1,2-epoxy-1-hydroxymethylpyrrolizidine and retronecine amounted to 0.23 and 0.15%, respectively, of the total carbon assimilated. Treatment of the shoots with alpha-dl-difluoromethylornithine, the specific ornithine decarboxylase inhibitor, at 1 to 2 millimolar had no effect on (14)C incorporation into the necines. In contrast, alpha-dl-difluoromethylarginine, the specific arginine decarboxylase inhibitor, prevented the incorporation of (14)C into the necines of both species; the inhibitor did not affect the absolute incorporation of (14)C from exogenous [1,4-(14)C] putrescine in either species. Thus, arginine is the only apparent endogenous precursor of the putrescine channeled into pyrrolizidines, at least in these two Heliotropium species that exhibited a relatively much higher in vitro activity of arginine decarboxylase than of ornithine decarboxylase. However, within 28 hours after administration, not only exogenous l-[5-(14)C]arginine, but also exogenous l-[5-(14)C]ornithine exhibited significant incorporation of their label into the necines, incorporation that could be partially prevented by both inhibitors. Neither inhibitor affected the rates of (14)C-labeled CO(2) assimilation, transformation of labeled assimilates into ethanol-insoluble compounds, or the very high degree of conversion of the introduced amino acids into other compounds. Methodology related to alkaloid biosynthetic studies is discussed.

Journal Article↗
PubMed1986

Birefringent objects visualized by circular polarization microscopy.

In the standard polarizing microscope, birefringent material appears bright only if its optic axis is oblique to the axes of the polarizer and analyzer filters; consequently, an object may be visualized as several disconnected bright regions. This confusing appearance is avoided if the crossed plane polarizers of the conventional microscope are replaced by circular polarizers of opposite handedness. All orientations of the optic axis in the focal plane then become equivalent; objects generally appear uniformly bright. Ordinary microscopes are easily modified to use this technic with readily available components.

Birefringence↗