Thyroid function, activated protein C resistance and the risk of venous thrombosis in users of hormonal contraceptives.

INTRODUCTION: Use of combined hormonal contraceptives is associated with a three- to eight-fold increased risk of venous thrombosis compared with non-use. The thrombotic risk depends on the estrogen dose as well as the progestogen type. Use of hormonal contraceptives leads to resistance to activated protein C (APC), which may serve as marker for the risk of venous thrombosis. Hyperthyroidism is also associated with an increased risk of venous thrombosis, due to increased free Thyroxine (FT4) levels which cause a hypercoagulable state. MATERIALS AND METHODS: The objective of this study was to evaluate the effects of hormonal contraceptives on levels of FT4, thyroid stimulating hormone (TSH) and thyroxine binding globulin (TBG), and to investigate the effects on APC resistance per contraceptive group. We measured FT4, TBG and TSH levels and APC resistance in 231 users of oral contraceptives. RESULTS: Users of the most thrombogenic hormonal contraceptives, i.e. containing desogestrel, cyproterone acetate or drospirenone, had higher TBG levels than users of less thrombogenic hormonal contraceptives, i.e. the levonorgestrel-containing intrauterine device. TSH levels were not significantly elevated and FT4 levels did not change. TBG levels were also associated with APC resistance. CONCLUSION: Use of hormonal contraceptives lead to elevated TBG levels, slightly elevated TSH levels and unchanged FT4 levels without causing a hyperthyroid state. Thus, the increased thrombotic risk during the use of hormonal contraceptives cannot be explained by a hyperthyroid state caused by use of these hormonal contraceptives.

Resistance to APC and SHBG levels during use of a four-phasic oral contraceptive containing dienogest and estradiol valerate: a randomized controlled trial.

BACKGROUND: The use of combined oral contraceptives is associated with a 3- to 6-fold increased risk of venous thrombosis. This increased risk depends on the estrogen dose as well as the progestogen type of combined oral contraceptives. Thrombin generation-based activated protein C resistance (APC resistance) and sex hormone-binding globulin (SHBG) levels predict the thrombotic risk of a combined hormonal contraceptive. Recently, a four-phasic oral contraceptive containing dienogest (DNG) and estradiol valerate (E2V) has been marketed. The aim of this study was to evaluate the thrombotic risk of the DNG/E2V oral contraceptive by comparing APC resistance by measuring normalized APC sensitivity ratios (nAPCsr) and SHBG levels in users of oral contraceptives containing dienogest and estradiol valerate (DNG/E2V) and oral contraceptives containing levonorgestrel and ethinyl estradiol (LNG/EE). METHODS: We conducted a single-center, randomized, open label, parallel-group study in 74 women using DNG/E2V or LNG/EE, and measured nAPCsr and SHBG levels in every phase of the regimen of DNG/E2V. RESULTS: During the pill cycle SHBG levels did not differ between DNG/E2V users and LNG/EE users. nAPCsr levels were overall slightly lower in DNG/E2V users than in LNG/EE users, mean difference -0.44 (95% CI, -1.04 to 0.17) for day 2, -0.20 (95% CI, -0.76 to 0.37) for day 7, -0.27 (95% CI, -0.81 to 0.28) for day 24 and -0.34 (95% CI, -0.91 to 0.24) for day 26. CONCLUSION: No statistical significant differences in nAPCsr and SHBG levels were found between users of the oral contraceptive containing DNG/E2V and LNG/EE, suggesting a comparable thrombotic risk.

Sex hormone-binding globulin as a marker for the thrombotic risk of hormonal contraceptives.

BACKGROUND: It takes many years to obtain reliable values for the risk of venous thrombosis of hormonal contraceptive users from clinical data. Measurement of activated protein C (APC) resistance via thrombin generation is a validated test for determining the thrombogenicity of hormonal contraceptives. Sex hormone-binding globulin (SHBG) might serve as a marker for the risk of venous thrombosis, and can be easily and rapidly measured in routine laboratories. OBJECTIVE: To determine whether SHBG is a useful marker for the thrombotic risk of hormonal contraceptive users by comparing plasma SHBG levels with normalized APC sensitivity ratio (nAPCsr) values and thrombosis risks reported in the recent literature. METHODS: We conducted an observational study in 262 users of different contraceptives, and measured nAPCsr and SHBG levels. RESULTS: Users of contraceptives with a higher risk of causing venous thrombosis, i.e. combined hormonal contraceptives containing desogestrel, cyproterone acetate or drospirenone, and the transdermal patch, had higher SHBG levels than users of combined hormonal contraceptives containing levonorgestrel, which carry a lower thrombosis risk. Users of the patch had the highest SHBG levels, with a mean difference of 246 nmol L(-1) (95% confidence interval 179-349) from that in users of levonorgestrel-containing combined hormonal contraceptives. SHBG levels were positively associated with both the nAPCsr and the risks of venous thrombosis reported in the recent literature. CONCLUSION: SHBG is a useful marker with which to estimate the thrombotic safety of a preparation.

Preparative isolation of glycoproteins from plasma membranes of different rat organs.

By a combination of high-performance affinity chromatographic (HPAC) methods, several membrane proteins from liver, Morris hepatoma and kidney were isolated. The use of a tandem system, consisting of a concanavalin A (ConA) and a wheat germ agglutinin (WGA) high-performance liquid chromatographic (HPLC) column, as a first purification step allowed the isolation of proteins directly from organ homogenates. In a subsequent step, the membrane proteins can be isolated by simply using a combination of immunoaffinity HPLC and preparative sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). However, with these methods most proteins lose their biological activity. If native proteins are required, a combination of different HPAC methods has to be applied. Several membrane proteins were isolated in milligram amounts under non-denaturing conditions using either HPAC columns or Mem Sep membranes with immobilized lectins, collagen, amino acids, crown ethers or heparin.

[Induction of anesthesia using propofol in comparison with etomidate]. / Narkoseeinleitung mit Propofol im Vergleich zu Etomidat.

Etomidate and propofol were compared for induction of anesthesia in a controlled study, including 24 male patients (ASA groups I and II). Following oral premedication with lormetazepam, the patients received propofol (2.5 mg kg-1; n = 12) or etomidate (0.3 mg kg-1; n = 12) over 60 s. For statistical analysis of the cardiovascular data (blood pressure and heart rate) four blocks were set up: A, baseline value including atropine dosage; B, value after induction of anesthesia; C, value after administration of halothane and vecuronium before intubation; D, value after intubation. The blood pressure fell slightly on administration of propofol while the heart rate remained nearly unchanged. Etomidate was associated with unacceptably high increases in blood pressure and heart rate. Myoclonia occurred in seven patients after etomidate and in two patients after propofol. A smoother mask ventilation was rated as a further advantage of propofol. Because of the unfavorable cardiovascular profile, the occurrence of myoclonia and poor mask ventilation, etomidate proved to be unsuitable for induction of anesthesia unless supplemented by an opioid and/or benzodiazepine. The high incidence of pain upon injection was considered to be a disadvantage of propofol.

Striatal syndrome following hyponatremia and its rapid correction. A manifestation of extrapontine myelinolysis confirmed by magnetic resonance imaging.

Several pathologic reports have indicated the occurrence of extrapontine sites of myelinosis associated with electrolyte disturbance and its rapid correction. Clinical evidence of the presence of such lesions, however, have rarely been described. We report a case of a 50-year-old man who following rapid correction of electrolyte imbalance developed a profound striatal syndrome. The clinical manifestations, the course of his illness as well as response to therapy, confirmation of lesion sites by magnetic resonance imaging (MRI), and abnormalities on visually evoked potentials are described in detail.