UMLS:C0376358 - FACTA Search

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Query: UMLS:C0376358 (prostate cancer)
59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The association of drinking water arsenic and mortality outcome was investigated in a cohort of residents from Millard County, Utah. Median drinking water arsenic concentrations for selected study towns ranged from 14 to 166 ppb and were from public and private samples collected and analyzed under the auspices of the State of Utah Department of Environmental Quality, Division of Drinking Water. Cohort members were assembled using historical documents of the Church of Jesus Christ of Latter-day Saints. Standard mortality ratios (SMRs) were calculated. Using residence history and median drinking water arsenic concentration, a matrix for cumulative arsenic exposure was created. Without regard to specific exposure levels, statistically significant findings include increased mortality from hypertensive heart disease [SMR = 2.20; 95% confidence interval (CI), 1.36-3.36], nephritis and nephrosis (SMR = 1.72; CI, 1.13-2.50), and prostate cancer (SMR = 1.45; CI, 1.07-1. 91) among cohort males. Among cohort females, statistically significant increased mortality was found for hypertensive heart disease (SMR = 1.73; CI, 1.11-2.58) and for the category of all other heart disease, which includes pulmonary heart disease, pericarditis, and other diseases of the pericardium (SMR = 1.43; CI, 1.11-1.80). SMR analysis by low, medium, and high arsenic exposure groups hinted at a dose relationship for prostate cancer. Although the SMRs by exposure category were elevated for hypertensive heart disease for both males and females, the increases were not sequential from low to high groups. Because the relationship between health effects and exposure to drinking water arsenic is not well established in U.S. populations, further evaluation of effects in low-exposure populations is warranted.
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PMID:Drinking water arsenic in Utah: A cohort mortality study. 1181 97

Recently, we have shown that ornithine decarboxylase (ODC), a rate-controlling enzyme in the polyamine biosynthetic pathway, is overexpressed in prostate cancer (PCA) and prostatic fluid in humans (R. R. Mohan et al., Clin. Cancer Res., 5: 143-147, 1999). ODC is also characterized as an androgen-responsive gene, and the androgenic stimulation regulates the development and growth of both normal and tumorigenic prostate cells. Thus, chemopreventive approaches aimed toward the modulation of ODC could be effective against PCA. Green tea polyphenols (GTPs) possess strong chemopreventive properties against a variety of animal tumor models and in some human epidemiological studies. At least two epidemiological studies have suggested that people who consume tea regularly may have a decreased risk of PCA. In this study, we investigated the effect of GTPs against testosterone-mediated induction of ODC in human prostate carcinoma cells, LNCaP as an in vitro model, and in Cpb:WU rats and C57BL/6 mice as in vivo models. Treatment of LNCaP cells with testosterone resulted in induction of ODC activity in a dose-dependent manner. Pretreatment of the cells with GTPs resulted in a significant inhibition of testosterone-caused induction of ODC activity in a dose-dependent manner. Similar effects of GTPs were observed in anchorage-independent growth assay of LNCaP cells where pretreatment of the cells with GTP was found to result in dose-dependent inhibition of colony formation. Testosterone treatment of the cells resulted in a significant increase in the level of ODC mRNA, and this increase was almost completely abolished by prior treatment of the cells with GTPs. The administration of testosterone (10 mg/kg body weight, i.p.) to sham-operated and castrated Cpb:WU rats resulted in 2- and 38-fold increases in ODC activity, respectively, in the ventral prostate. Oral feeding of 0.2% GTPs in drinking water for 7 days before testosterone administration resulted in 20 and 54% decreases in testosterone-caused induction of ODC activity in sham-operated and castrated rats, respectively. Similar results were obtained with C57BL/6 mice, where testosterone treatment at similar dosage resulted in a 2-fold increase in ODC activity in the ventral prostate and prior oral feeding with 0.2% GTPs resulted in 40% inhibition in this induction.
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PMID:Prostate cancer chemoprevention by green tea: in vitro and in vivo inhibition of testosterone-mediated induction of ornithine decarboxylase. 1023 97

We have used selected ion flow tube mass spectrometry (SIFT-MS) to determine the concentration of formaldehyde in the headspace of urine from patients suffering from bladder and prostate cancer and from several healthy subjects as controls. We address the potential problems associated with the use of ion chemistry to quantify formaldehyde in the presence of the relatively large number densities of water molecules and show that formaldehyde can be quantified in urine headspace using analysis by SIFT-MS. These studies show that formaldehyde is clearly elevated in the headspace of the urine from the cancer patients as compared with urine from the healthy controls. Thus, with further improvements in the methodology and the sensitivity of our SIFT-MS technique, formaldehyde quantification in urine headspace using this new analytical method could be a valuable non-invasive indicator of the presence of early-stage tumours in the body.
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PMID:Analysis of formaldehyde in the headspace of urine from bladder and prostate cancer patients using selected ion flow tube mass spectrometry. 1040 24

Understanding the dynamics and pathogenesis of invasion is vital for developing strategies to prevent cancer metastasis. Conventional invasion assays provide information for a single time point. NMR microscopic imaging as used in the current study to measure cell invasion in vitro provides a nondestructive method for scoring cell invasion thus offering a unique possibility to study this process dynamically. An additional advantage is that cells can be retrieved for metabolic and physiological characterization. Two prostate cancer cell lines, DU-145 and Mat-Ly-Lu, preselected for differences in invasive behavior, were studied. Cells were seeded in 12-mm culture plate inserts containing a 15-microm-thick porous membrane with 3.0 microm pore size that was coated with a 100 microm Matrigel layer. Cell invasion in the Matrigel layer was obtained from the profile of intracellular water measured with diffusion-weighted 1D imaging. Additional experiments were also performed with confocal microscopy to validate the NMR results. Significant differences were detected between the invasive behavior of DU-145 and Mat-Ly-Lu cells. The obtained results show that NMR microscopy can be used to dynamically study invasion by cancer cells. The noninvasive nature of NMR microscopy permits determination of cell migration dynamically for any given sample, which is especially important if cell availability is limited to the unique sample, such as for biopsy specimens. Magn Reson Med 42:277-282, 1999.
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PMID:Dynamics of prostate cancer cell invasion studied in vitro by NMR microscopy. 1044 Sep 52

The enzyme 17alpha-hydroxylase/17,20-lyase (P-450(17alpha) has recently become the focus of research into the fight against hormone dependent prostate cancer. However, the specific nature of this enzyme, in particular, the dual role of its active site, remains unknown. In our drive to elucidate further information regarding P-450(17alpha), and in light of our experience of other cytochrome P-450 enzymes, we chose to consider each part of this complex enzyme separately (i.e. the 17alpha-hydroxylase (17alpha-OHase) and the 17,20-lyase components). We therefore initiated a series of molecular modelling studies involving the construction of a 'substrate heme complex' for each of the two components. Here, we consider the construction and use of the complex for the 17alpha-OHase component of this enzyme. Using this approach, we have successfully considered: the binding of steroidal and non-steroidal reversible inhibitors: the structural features necessary for potent inhibition: and, rationalised the mode of action of a number of compounds whose inhibitory activity has not been previously explained, for example aminoglutethimide (an inhibitor of another related cytochrome P-450 enzyme, aromatase AR). The study concludes that the ability of the inhibitors of 17alpha-OHase to undergo polar polar interaction with the active site and for the compounds to closely mimic the substrate plane is a major factor in determining potency. Factors such as log P (log of the partition coefficient value for the distribution of a compound between octanol and water) would then appear to determine the extent of overall inhibitory activity. Overall, the study suggests that the novel substrate-heme complex approach has provided a good approximation of the 17alpha-OHase active site and has proved to be a useful tool in drug design and discovery.
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PMID:A novel molecular modelling study of inhibitors of the 17alpha-hydroxylase component of the enzyme system 17alpha-hydroxylase/17,20-lyase (P-450(17alpha)). 1048 40

Low-energy gamma emitting isotopes encapsulated for permanent implant are in routine use in the treatment of prostate cancer. New source designs require full dosimetric analysis and calibration standardization before responsible clinical application. The results of one such experimental measurement and analysis are here reported for a new design of 103palladium source, model MED3633 (North American Scientific, Inc.). By AAMP Task Group #43 recommendations, the reference material for brachytherapy dosimetry is liquid water. The dose measurements were made using standard methods employing thermoluminescent dosimeters in a water equivalent plastic phantom. Precision machined bores in the phantom located dosimeters and source(s) in a reproducible fixed geometry providing for transverse-axis and angular dose profiles over a range of distances from 0.17 to 7 cm. The data were analyzed in terms of parameters recommended by AAPM TG43. The dose-rate constant, lambda, was evaluated with reference to a 60 cobalt standard, accounting for response variation with isotope energy spectrum. The radial dose function, g(r), the anisotropy function, F(r, theta), the anisotropy factor, phi,un(r), and the point-source approximation anisotropy constant, phi(un), were derived from one- and two-dimensional dose distribution data measured in the phantom, accounting for finite dosimeter volume and with attention to interchip effects. The results are compared to TG43 and other existing data for 103Pd sources. The new source is comparable to the model 200 103Pd source design, demonstrating equivalent radial dose function, g(r). The dose surrounding a MED3633 source may be slightly more isotropic than for the model 200 source. The air-kerma strength of the MED3633 source used in this study was provided by the manufacturer and is traceable to the NIST 1999 standard. The evaluated dose-rate constant, lambda, with NIST traceable strength calibration is lower than that of the model 200 source, with that manufacturer's strength calibration.
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PMID:Dosimetric characterization of a new design 103 palladium brachytherapy source. 1058 34

In previous in situ point-resolved spectroscopy (PRESS) three-dimensional (3D) 1H magnetic resonance (MR) spectroscopic imaging studies, it has been demonstrated that the ratio of prostatic metabolites can noninvasively discriminate prostate cancer from surrounding normal tissue. However, in these studies, conventional chemical shift selective suppression (CHESS) and short-time inversion recovery (STIR) techniques often resulted in inadequate water and lipid suppression. To improve suppression and spatial coverage, the newly developed T1 insensitive dual band selective inversion with gradient dephasing (BASING) Bandstop Filter and dual phase-compensating spectral/spatial spin-echo pulses have been implemented in a clinical setting. In phantom studies, no change in metabolic profiles was observed with application of either BASING or spectral/spatial pulses. In a study of 17 prostate cancer patients, the use of either BASING or spectral/spatial pulses allowed for suppression of water (BASING 99.80 +/- 0.14% and spectral/spatial 99.73 +/- 0.47%) and lipid (BASING 98.56 +/- 1.03% and spectral/spatial 98.44 +/- 1.90%) without a significant difference in the prostatic metabolite ratios. Spectral/spatial suppression has the added advantage of reducing the chemical shift dependence of the PRESS volume, but optimal performance requires high-speed gradients with negligible eddy current effects. BASING suppression is less reliant on accurate pulse and gradient timings and can be implemented easily with no loss in performance on clinical MR scanners with conventional gradients.
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PMID:Clinical application of BASING and spectral/spatial water and lipid suppression pulses for prostate cancer staging and localization by in vivo 3D 1H magnetic resonance spectroscopic imaging. 1064 27

The possible association between the increased risk of prostate cancer and the levels of calcium and magnesium in drinking water from municipal supplies was investigated in a matched cancer case-control study in Taiwan. All eligible prostate-cancer deaths (682 cases) of Taiwan residents from 1987 through 1993 were compared with deaths from other causes (682 controls). The levels of calcium and magnesium in the drinking water of these residents were also determined. Data on calcium and magnesium levels in drinking water throughout Taiwan were obtained from the Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes, and the controls were pair-matched to the cases by year of birth and death. The adjusted odds ratios for prostate cancer death for those with higher magnesium levels in their drinking water, as compared to the lowest tertile, were 0.73 (95% CI = 0.51-1.03) and 0.64 (95% CI = 0.43-0.96), respectively. The adjusted odd ratios for the relationship between calcium levels in drinking water and prostate cancer were not statistically significant. The results of the present study show that there may be a significant protective effect of magnesium intake from drinking water and other dietary sources against the risk of prostate cancer development.
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PMID:Calcium and magnesium in drinking water and risk of death from prostate cancer. 1083 15

The EGS4 Monte Carlo radiation transport code was used to systematically study the dose perturbation near planar and cylindrical air cavities in a water medium irradiated by megavoltage x-ray beams. The variables of the problem included x-ray energy, cavity shape and dimension, and depth of the cavity in water. The Monte Carlo code was initially validated against published measurements and its results were found to agree within 2% with the published measurements. The study results indicate that the dose perturbation is strongly dependent on x-ray energy, field size, depth, and size of cavity in water. For example, the Monte Carlo calculations show dose reductions of 42% and 18% at 0.05 and 2 mm, respectively, beyond the air-water interface distal to the radiation source for a 3 cm thick air slab irradiated by a single 5x5 cm2 15 MV beam. The dose reductions are smaller for a parallel-opposed pair of 5x5 cm2 15 MV x-ray beams, being 21% and 11% for the same depths. The combined set of Monte Carlo calculations showed that the dose reduction near an air cavity is greater for: (a) Smaller x-ray field size, (b) higher x-ray energy, (c) larger air-cavity size, and (d) smaller depth in water where the air cavity is situated. A potential clinical application of these results to the treatment of prostate cancer is discussed.
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PMID:A systematic evaluation of air cavity dose perturbation in megavoltage x-ray beams. 1084 4

Permanent prostate implantation using 125I (iodine) or 103Pd (palladium) sources is a popular treatment option in the management of early prostate cancer. As sources of new designs are developed and marketed for application in permanent prostate implantations, their dosimetric characteristics must be carefully determined in order to maintain the accuracy of patient treatment. This report presents the results of experimental measurements and Monte Carlo calculations of the dosimetric parameters performed for a newly available 103Pd seed source. The measurements were performed in a large scanning water phantom using a diode detector. The positioning of the source and detector was achieved by a computer-controlled positioning mechanism in the scanning water phantom. The dose rate constant in water for the new 103Pd source was determined from measurements with the diode detector calibrated with 125I sources of known air-kerma strength. The radial dose function values for the source were measured using the diode detector. Monte Carlo photon transport calculations were then used to calculate the dosimetric parameters of dose rate constant, radial dose function, and anisotropy function using an accurate geometric model of the source. The measured dose rate constant of 0.693 cGy/U-hr compares well with the Monte Carlo calculated value of 0.677 cGy/U-hr. These results are further compared with data on existing 103Pd sources.
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PMID:Monte Carlo calculations and experimental measurements of dosimetry parameters of a new 103Pd source. 1084 16

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