Biomedical subjects

G Gahn

Publications and source records attributed to G Gahn.

22 records · Page 2Linked to original sources

PubMed1985

A randomized cross-over comparison of two low-dose oral contraceptives upon hormonal and metabolic parameters: I. Effects upon sexual hormone levels.

The effect of a low-dose triphasic oral contraceptive (OC) containing ethinyl estradiol and levonorgestrel (EE/NG) upon serum levels of endogenous sexual hormones was compared to that of a preparation containing EE and desogestrel (EE/DG). Blood samples were taken on Day 6, 11, 21, and 28 of a control cycle and of the third cycle of treatment with either the EE/NG or EE/DG preparation (11 volunteers each). After a washout period of 3 months, the contraceptives were changed in a cross-over fashion. Blood samples were again taken on Day 6, 11, 21, and 28 of the third washout cycle and the third treatment cycle. There was no significant suppression of serum LH and FSH during treatment with EE/NG and EE/DG except on Day 21, while estradiol levels were significantly lowered. Similar to the gonadotropin concentrations, the estrogen levels showed great individual variations; although they were depressed in the majority of the women, there was a considerable stimulation of follicular activity in 36% of the women under EE/NG and 18% under EE/DG. Both EE/NG and EE/DG suppressed significantly serum progesterone, testosterone, and DHEA-S, while prolactin was unaffected. In three cases an escape ovulation seemed to have occurred, but no pregnancy was observed. The spottings (8/22 women) and breakthrough bleedings (6/22 women) did not correlate with the serum levels of estradiol. The results indicate that the suppression of gonadotropin secretion during treatment with low-dose OC is a time-dependent process which in some women may be at or below the threshold of safe ovulation inhibition.

Adult↗

PubMed1985

A randomized cross-over comparison of two low-dose oral contraceptives upon hormonal and metabolic serum parameters: II. Effects upon thyroid function, gastrin, STH, and glucose tolerance.

The effect of a low-dose triphasic oral contraceptive (OC) containing ethinyl estradiol and levonorgestrel (EE/NG) upon thyroid function and some other biochemical serum parameters was compared to that of a preparation containing EE and desogestrel (EE/DG). Blood samples were taken on Day 6, 11, 21, and 28 of a control cycle and of the third cycle of treatment with either the EE/NG or EE/DG preparation (11 volunteers each). After a washout period of 3 months, the contraceptives were changed in a cross-over fashion. Blood samples were again taken on Day 6, 11, 21, and 28 of the third washout cycle and the third treatment cycle. There was a significant increase (13%) in basal glucose level during treatment with both OC, but no change in glucose tolerance. Both the EE/NG and FE/DG preparation elevated serum T4 (40%), FT4 (15-22%), T3 (17-28%), and TBG (20%) significant, whereby the effect was more pronounced during the second treatment period after washing-out. The effective thyroxine ratio (ETR) was slightly (4%) but significantly increased. Contrary to this, the levels of FT3, reverse T3 (rT3), TSH, and gastrin were not altered. STH showed great individual fluctuations, but was significantly elevated by 50% during treatment with both OC. There was no effect of endogenous estradiol upon thyroid or other parameter, even though it was raised considerably in some women under OC. Although the increase in T4 and T3 is probably due to a rise in estrogen-induced TBG production, the data seem to indicate that there is a slight but effective stimulation of thyroid function during treatment with low-dose OC.

Adult↗

PubMedDate not supplied

Noninvasive assessment of the circle of Willis in cerebral ischemia: the potential of CT angiography and contrast-enhanced transcranial color-coded duplexsonography.

Thirty-four patients with acute hemispheric ischemic strokes underwent both CT angiography and contrast-enhanced transcranial color-coded duplexsonography (TCCD) to study the effectiveness of the combined noninvasive techniques for evaluation of the circle of Willis. In 3/34 patients, CT angiography and contrast-enhanced TCCD demonstrated middle cerebral artery (MCA) occlusion, in 5 others MCA stenosis. A severe posterior cerebral artery stenosis was missed by CT angiography. In 8 patients, contrast-enhanced TCCD failed because of poor bone windows. In these patients, CT angiography was normal. CT angiography and contrast-enhanced TCCD are complementary noninvasive diagnostic tools. Disagreements between the diagnostic findings of these methods still need further evaluation by digital subtraction angiography.

Aged↗

PubMedDate not supplied

Echo-enhanced transcranial color-coded duplex sonography in the diagnosis of cerebrovascular events: a validation study.

BACKGROUND AND PURPOSE: Transcranial color-coded duplex sonography (TCCD) is a diagnostic technique for evaluation of intracranial arteries in patients with acute stroke. Echo-enhancing contrast agents (EEAs) are necessary to visualize intracranial vessels in up to 30% of patients because of limited acoustic bone windows. In this study, we assessed the diagnostic efficacy of echo-enhanced TCCD (eTCCD) in correlation with the gold standard, digital subtraction angiography (DSA). METHODS: We prospectively evaluated all patients with eTCCD who subsequently underwent DSA for evaluation of cerebrovascular symptoms over a 24-month period. We administered Levovist as an EEA. Two blinded reviewers analyzed all eTCCD findings and correlated them with DSA. RESULTS: We included 132 consecutive patients (40 women, 92 men; mean age, 58 +/- 14 years) with 164 datasets: 24/164 had normal findings, 98/164 had abnormalities of extracranial carotid arteries, 32/164 had abnormalities of intracranial arteries, and 21/164 had abnormalities in vertebrobasilar circulation as determined by DSA. For eTCCD, we found a sensitivity of 82% (95% confidence interval [CI]: 75%-90%), a specificity of 98% (95% CI: 90%-100%), a positive predictive value of 99% (95% CI: 94%-100%), and a negative predictive value of 75% (95% CI: 64%-85%); 7/164 (4%) examinations were inconclusive because of insufficient bone windows. The interobserver agreement was almost perfect (kappa value, 0.92; 95% CI: 0.87-0.97). CONCLUSION: eTCCD provides high diagnostic validity for the status of the major intracranial arteries. In particular, a normal vessel status reliably assessed by an experienced sonographer could supersede further imaging procedures. In patients with acute ischemic stroke not eligible for established angiographic techniques, eTCCD may be useful as an alternative imaging technique.

Adolescent↗