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Biomedical subjects

J Elbers

Publications and source records attributed to J Elbers.

6 recordsLinked to original sources
PubMed2006

Tibolone (Livial) enhances warfarin-induced anticoagulation in postmenopausal women.

OBJECTIVE: To investigate the potential drug interaction between tibolone and warfarin in healthy postmenopausal women. METHODS AND RESULTS: The study was designed as a double-blind, randomized, placebo-controlled, two-way crossover study in postmenopausal women. After stabilization of the International Normalized Ratio (INR; a standardized prothrombin time, PT) between 1.4 and 2.0 with warfarin, subjects were randomized to receive either tibolone (2.5mg/day) or placebo for 21 days. After a 7-day wash-out period (during which warfarin treatment was continued) the treatments were crossed over. Primary efficacy parameters were INR and coagulation Factors II, VII, VIIa and X (means of measurements at Days 18 and 20 and Days 46 and 48). Treatment with tibolone induced a statistically significant increase in INR (estimate of mean difference=0.40; P=0.002), and a statistically significant decrease in coagulation factors. Treatments were generally well tolerated and no clinically significant adverse events were observed. CONCLUSIONS: Tibolone enhances warfarin-induced anticoagulation in postmenopausal women, as reflected by increases in INR and decreases in coagulation Factors II, VII, VIIa and X, compared to placebo. It is advisable to monitor for changes in coagulation status during (and after discontinuation of) simultaneous use of tibolone and warfarin.

Aged↗
PubMed2002

Using polymer mats to biodegrade atrazine in groundwater: laboratory column experiments.

Large-scale column experiments were undertaken to evaluate the potential of in situ polymer mats to deliver oxygen into groundwater to induce biodegradation of the pesticides atrazine, terbutryn and fenamiphos contaminating groundwater in Perth, Western Australia. The polymer mats, composed of woven silicone (dimethylsiloxane) tubes and purged with air, were installed in 2-m-long flow-through soil columns. The polymer mats proved efficient in delivering dissolved oxygen to anaerobic groundwater. Dissolved oxygen concentrations increased from <0.2 mg l(-1) to approximately 4 mg l(-1). Degradation rates of atrazine in oxygenated groundwater were relatively high with a zero-order rate of 240-380 microg l(-1) or a first-order half-life of 0.35 days. Amendment with an additional carbon source showed no significant improvement in biodegradation rates, suggesting that organic carbon was not limiting biodegradation. Atrazine degradation rates estimated in the column experiments were similar to rates determined in laboratory culture experiments, using pure cultures of atrazine-mineralising bacteria. No significant degradation of terbutryn or fenamiphos was observed under the experimental conditions within the time frames of the study. Results from these experiments indicate that remediation of atrazine in a contaminated aquifer may be achievable by delivery of oxygen using an in situ polymer mat system.

Atrazine↗
PubMed2001

Lowering of HDL cholesterol in post-menopausal women by tibolone is not associated with changes in cholesterol efflux capacity or paraoxonase activity.

Low HDL cholesterol increases the risk of coronary heart disease. Treatment of postmenopausal women with tibolone lowers HDL cholesterol. We elucidated the consequences of this unwanted side effect in a randomized, double-blind study, where 12 women received 2.5 mg tibolone per day and 6 women, placebo. Blood samples were collected on days -1 (i.e. baseline), 28, 56, and 84 for the analysis of various parameters of lipid metabolism and HDL function. Compared to placebo, treatment with tibolone led to statistically significant decreases of HDL cholesterol (-22% to -32%), apoA-I (-14% to -22%), and HDL subclass LpA-I (-30% to -40%) but to no significant changes in apoA-II and HDL subclass LpA-I,A-II. These changes were not associated with statistically significant changes in the activity of plasma to release 3H-cholesterol from radiolabeled fibroblasts or in the serum activity of the anti-oxidative enzyme paraoxonase/arylesterase. There were no significant changes in either serum levels of triglycerides, LDL cholesterol, apoB, and leptin, or in LDL size. We conclude that changes in insulin do not contribute to the lowering of HDL cholesterol by tibolone. Despite decreased HDL cholesterol, putatively anti-atherogenic activities of HDL remained unchanged.

Aged↗
PubMed1987

Characterization of two human cell lines (TK-10, TK-164) of renal cell cancer.

Two previously unreported cell lines of human renal cell carcinoma are presented. TK-10 and TK-164 have each been in culture for over 4 years. The epithelial nature of both cell lines has been documented by light and electron microscopy. The cells in each line contain a Y chromosome, have specific marker chromosomes, and a distinct flow cytometric histogram. Both lines grow in agar, albeit not in athymic mice.

Adult↗
PubMed1987

Percutaneous nephrostomy: assessment of renal damage associated with semi-rigid (24F) and balloon (36F) dilation.

In an effort to discern the amount of renal damage incurred by antegrade percutaneous nephrostomy and nephrostomy tract dilation, we studied the long-term effect of acutely created 24F and 36F percutaneous nephrostomy tracts on 12 pig kidneys. Half of the nephrostomy tracts were dilated using a semi-rigid 24F fascial dilating system (Amplatz design) and half were dilated using a 36F balloon dilation system. Animals were killed at six weeks and the nephrostomy tract was dissected, fixed in formalin, and microscopic cross-sections were stained with Masson's trichrome stain for collagen prior to morphometry using computerized planimetry. In this study, renal damage from the nephrostomy tract averaged 0.15% of the total renal cortical surface. Balloon dilation to 36F incurred no more significant damage than fascial dilation to 24F.

Animals↗