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Biomedical subjects

H Welti

Publications and source records attributed to H Welti.

At least 19 recordsLinked to original sources
PubMed1987

Fibrinolysis in pregnancy: a study of plasminogen activator inhibitors.

During pregnancy the plasma concentration of two different inhibitors of plasminogen activators (PAIs) increases. The only one found in the plasma of nonpregnant women (PAI1) is immunologically related to a PAI of endothelial cells; its plasma activity, as deduced from the inhibition of single-chain tissue-type plasminogen activator (t-PA), increased from 3.4 +/- 2.3 U/mL (mean +/- 95% confidence limits) in the plasma of nonpregnant women to 29 +/- 7 U/mL at term, and its antigen level, measured by a radioimmunoassay, increased from 54 +/- 17 ng/mL to 144 +/- 25 ng/mL. In pregnancy plasma a second PAI (PAI 2) related to a PAI found in placenta extracts was observed. Its level, quantified with a radioimmunoassay, increased from below the detection limit (approximately 10 ng/mL) in normal plasma to 260 ng/mL at term. One hour after delivery, PAI 1 activities and antigen decreased sharply, but the PAI 2 antigen levels remained constant. Three days later, the PAI 1 antigen levels had fallen to normal levels, but the PAI 2 antigen levels were still at least eightfold above the nonpregnant values. During pregnancy, the t-PA and prourokinase (u-PA) antigen concentrations increased 50% and 200%, respectively, whereas the plasminogen and alpha 2-antiplasmin levels remained constant. Despite the large variations in the levels of PAs and PAIs, the overall fibrinolytic activity as measured in diluted plasma by a radioiodinated fibrin plate assay did not change significantly. Just after delivery, a great increase in the t-PA antigen levels was observed. Three to five days after delivery most parameters of the fibrinolytic system were normal again. Our results demonstrate that during pregnancy and in the puerperium profound alterations of the fibrinolytic system occur that are characterized by increases in PAs and their inhibitors, but these alterations do not affect the overall fibrinolytic activity.

Adult↗
PubMed1985

[Post-coital contraception using a combination of d-norgestrel and ethinyloestradiol].

This study was conducted to assess the efficacy of d-Norgestrel associated with Ethinylestradiol (Neogynon 21) as postcoital contraception and to report on the clinical experience obtained with this type of contraception. 323 women were treated during 72 h. period following unprotected intercourse. All subjects received 0,2 mg Ethinylestradiol and 1 mg d-Norgestrel (Levonorgestrel) in 2 equally divided doses 12 hours apart. - 1 mg Levonorgestrel was observed to be as effective as 2 mg of the racemic Norgestrel. PCC given during the first part of the cycle, shortened the latter in 80% of relevant cases. Nausea occurred in 30.3% of all patients; among these 14.2% also mentioned vomiting. Three pregnancies occurred of which only one could be attributed to method failure. The corrected failure rate is thus estimated at 0.3%.

Adolescent↗
PubMed1978

Effect of the menstrual cycle, oral contraception and pregnancy on forearm blood flow, venous distensibility and clotting factors.

Forearm blood flow, venous distensibility and various clotting factors were determined in 118 apparently healthy women (mean age 26 years), either during the menstrual cycle, or while taking a combined contraceptive (A) with high progestin:estrogen ratio (d-norgestrel 0.125 mg + ethinylestradiol 0.03 mg), or a sequential contraceptive (B) with low progestin: estrogen ratio (megestrol 0.1/1 mg + ethinylestradiol 0.1 mg), or in the 1st, 2nd and 3rd trimester of pregnancy. Venous distensibility in women taking contraceptive A was higher than in other women during the follicular phase of a normal menstrual cycle. Venous distensibility was not affected by contraceptive B. Blood flow and blood pressure remained unchanged by contraceptives A and B. Fibrinogen concentration was increased by both contraceptives, factor VII was either decreased (A) or unchanged (B), and factor X was either unchanged (A) or increased (B). The oral contraceptive with the high progestagen component appeared to increase venous capacitance and may induce venous stasis, whereas coagulability was particularly enhanced by the estrogen-type contraceptive. Pregnant women differed from women on oral contraceptives in regard to peripheral circulation; they showed a tremendous increase of blood flow with secondary vasodilation.

Adult↗