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Biomedical subjects

A Victor

Publications and source records attributed to A Victor.

At least 55 records · Page 3Linked to original sources
PubMed1982

Serum lipoprotein and apolipoprotein changes during treatment with a contraceptive vaginal ring containing levonorgestrel and estradiol.

Contraceptive vaginal rings containing estradiol and levonorgestrel were used by 22 women during 219 cycles. The estrogenicity was low and the daily dose of levonorgestrel was about 290 micrograms. The triglyceride and cholesterol concentrations decreased in whole serum and, to varying degrees, in the different lipoprotein classes. The most consistent change was a 25% (p less than 0.001) reduction in the cholesterol content of the high-density lipoprotein (HDL) fraction. The cholesterol concentration in low-density lipoprotein decreased by 11% after the first 3 months, but increased during the ensuing 9 months of treatment to regain pretreatment level. Percentage-wise, the apolipoprotein B and A-I concentrations, determined by rocket immunoelectrophoresis, were less affected than the LDL- and HDL-cholesterol concentrations. The composition of the LDL and HDL particles seemed thus to alter during the treatment. The pronounced effect on the HDL levels seen is consistent with earlier findings of a dose-dependent, androgenic effect of gestagens derived from 19-nortestosterone. However, the low basal level of LDL and its further decrement during treatment alleviate the supposedly unfavorable effect of HDL reduction from the atherogenic point of view.

Adult↗
PubMed1981

A multicenter study of levonorgestrel-estradiol contraceptive vaginal rings. II-Subjective and objective measures of effects. An international comparative trial.

Comparative clinical trials of 2 sizes of contraceptive vaginal rings and of an oral contraceptive were undertaken at 8 investigational sites (9 clinics). More than 500 women enrolled on each of the 3 study regimens. Side effects of the rings and of Nordette, the oral contraceptive, were evaluated by noting spontaneous complaints, by recording medications taken and by physical examination. Inquiries about changes in the frequency of specific conditions were made at the end of the subjects participation in the first year of the study. The incidence of spontaneous complaints was similar among users of the 2 different-sized rings and of the pill.

Adolescent↗
PubMed1981

A multicenter study of levonorgestrel-estradiol contraceptive vaginal rings. III-Menstrual patterns. An international comparative trial.

Menstrual events among users of contraceptive vaginal rings (CVRs), releasing levonorgestrel and estradiol, were studied in comparison with a combined oral contraceptive, Nordette, in multicentered trials. CVRs were made with outside diameters of 50 and 58 mm and released about 250 micrograms and 290 microgram of levonorgestrel and 150 microgram and 180 microgram of estradiol per day, respectively. The CVRs were used continuously for 3 weeks and then removed for 1 week. Both the CVRs and Nordette were perceived to reduce menstrual flow and days of menstrual bleeding. Twenty to 25% of CVR users perceived increased intermenstrual bleeding or spotting. Diaries indicate, however, that on average, CVR users experienced about 1 day per month of bleeding or spotting with the ring in place. CVRs and Nordette produced approximately the same total number of bleeding and spotting days during 6 cycles of use, 27-29, but the small (50-mm OD) ring was associated with somewhat more spotting. This ring was also associated with somewhat more prolonged bleeding and spotting runs and with more prolonged nonbleeding intervals than reported by users of the larger (58-mm OD) ring or of Nordette. Differences among regimens, however, tended to be small even when statistically significant. Evidence from menstrual diaries indicates that these CVRs, and in particular 58-mm ring, provide control over the menstrual cycle comparable to the Nordette.

Adolescent↗
PubMed1981

Comparison of the metabolic effects of two hormonal contraceptive methods: an oral formulation and a vaginal ring. I. Carbohydrate metabolism and liver function.

A prospective, long-term study was undertaken to compare the metabolic effects of a contraceptive vaginal ring releasing levonorgestrel (about 290 microgram per day) and estradiol (about 180 microgram per day) and a combined oral contraceptive containing 30 microgram ethinylestradiol and 150 microgram levonorgestrel in two groups of women (n = 22 and 20, respectively). An intravenous glucose tolerance test, including determination of the insulin response to glucose, and liver function tests were performed. Both the glucose tolerance and fasting values of glucose were unaltered. The early insulin response to glucose increased by 50 percent in the contraceptive ring roup after one year of treatment, but not in the oral contraceptive group. All other insulin values were unchanged. All liver function values remained within the normal range in all subjects. There was a small significant decrease in alkaline phosphatases in both groups, which is in contrast to the effects of the early combined pills, which could cause an elevation. It is concluded that neither of these two contraceptive methods, the effects of which are predominantly gestagenic, seems to cause impairment of glucose tolerance or hepatic function.

Blood Glucose↗
PubMed1981

Comparison of the metabolic effects of two hormonal contraceptive methods: an oral formulation and a vaginal ring. II. Serum lipoproteins and apolipoproteins.

In a long-term, prospective study the effects on lipoprotein lipids and apolipoproteins (apo) of a combined oral contraceptive (OC) (30 micro gram ethinylestradiol and 150 micro gram levonorgestrel) and a contraceptive vaginal ring (CVR) releasing estradiol (about 180 micro gram per day) and levonorgestrel (about 290 micro gram per day) were compared. The two treatments induced significantly different effects. In the OC group the lipoprotein-lipid concentrations showed only minor changes, but apolipoproteins (apo) B and A-I increased by about 15%. In contrast, during treatment with the CVR there was a 25% decrement of cholesterol in high density lipoprotein (HDL) and at most 10% in low density lipoprotein (LDL) cholesterol, with only minor effects on apo B and A-I. The ratio of LDL and HDL cholesterol increased in the CVR group but not in the OC group. The results also indicate a change in the composition of the LDL and HDL particles, with an altered lipid/protein ratio, during both contraceptive treatments. Despite the impressive relative increase in LDL:HDL ratio in the contraceptive ring group, the average absolute value of this ratio did not reach the mena for healthy men.

Adolescent↗
PubMed1981

Pharmacokinetics and pharmacodynamic effects of vaginal oestradiol administration from silastic rings in post-menopausal women.

Silastic rings releasing approximately 200 microgram of 17beta-oestradiol per day were inserted into the vaginas of 4 post-menopausal women for one to three 21-day periods. Plasma concentrations of oestrone and oestradiol were analysed by radioimmunoassay. The effect of circulating oestrogens on FSH, LH and sex-hormone binding globulin (SHBG) levels as the well as on the endometrium was studied. During the first 24 h of treatment the plasma oestradiol levels were higher than the oestrone levels. But during the following days of the 21-day periods, the levels of the two oestrogens were almost equal, varying between about 100 and 200 pg/ml plasma, a pattern similar to that seen in fertile women. the release of oestradiol from the ring gave stable plasma oestrogen levels. The FSH and LH levels were clearly depressed while the SHBG levels did not change. Characteristics of oestrogen influence were found in endometrial biopsies. The rings were well accepted and could be inserted and removed easily by the women. Absorption of oestradiol from the vagina is good and more complete than after oral administration allowing lower doses to be used for treatment.

Estradiol↗
PubMed1980

Endometrial effects of levonorgestrel and estradiol: A Scanning electron microscopic study of the luminal epithelium.

Fertile women in the follicular phase possessed an uterine luminal surface with many ciliated cells and with non-ciliated cells, which carried numerous, fairly long microvilli. A moderate number of the non-ciliated cells had an irregular surface with small apical protrusions. Postmenopausal women had an endometrial surface containing rather flat cells. Ciliated cells were seldon encountered, and the non-ciliated cells possessed mostly only few short microvilli. When menopausal women had been wearing estradiol-containing intravaginal rings for three weeks, the uterine surface had developed many ciliated cells, and the non-ciliated cells now possessed many long microvilli. This appearance resembles that appearing during the follicular phase. Fertile women with levonorgestrel-containing subdermal implants or intravaginal rings showed a surface epithelium with few ciliated cells and with non-ciliated cells possessing short and irregular microvilli; that is, an epithelium less developed than that from a cyclic women. Adding estradiol to the levonorgestrel-containing intravaginal rings resulted in an estrogen response with an increase in number and length of the microvilli and an appearance of a few small apical protrusions.

Endometrium↗
PubMed1980

Effects on sex hormone binding globulin of different oral contraceptives containing norethisterone and lynestrenol.

Six combined oral contraceptive drugs containing ethinyloestradiol or mestranol and norethisterone or lynestrenol were studied throughout six 21-day cycles in healthy female volunteers. There was always one menstrual cycle without treatment between every treatment cycle. Plasma levels of norethisterone were determined throughout treatment by use of a specific radioimmunoassay. Sex hormone binding globulin (SHBG) was measured by an ammonium sulphate precipitation method at the beginning and at the end of each treatment cycle. The results indicated an accumulation of norethisterone in plasma when 1 to 3 mg of norethisterone or lynestrenol was given. There was no obvious accumulation during treatment with 0.5 mg norethisterone. SHBG increased during treatment with all combinations studied. However, this increase was most pronounced with the 50 microgram ethinyloestradiol/l mg lynestrenol, 50 microgram mestranol/l mg norethisterone and 35 microgram ethinyloestradiol/0.5 mg norethisterone combinations. There was no statistically significant increase in SHBG with 50 microgram ethinyloestradiol/2.5 mg lynestrenol or 50 microgram ethinyloestradiol/3 mg norethisterone acetate combinations. The results indicated that the induction of SHBG by the synthetic oestrogens was antagonized by the progestogens in a dose-dependent manner. The effect on SHBG by a combind preparation could be one assessment of the oestrogenicity or androgenicity of the preparation.

Adult↗
PubMed1979

Plasma levels of norethindrone after single oral dose administration of norethindrone and lynestrenol.

Single oral doses of 0.3 mg, 0.5 mg and 5 mg Norethindrone (NET) and 0.5 mg and 5 mg Lynestrenol (lyn) were given to five women. Lynestrenol is probably metabolized through NET and exerts its main biological activity as NET. Plasma concentrations of NET were determined by a radioimmunoassay at different intervals after administration of the tablets. Peak concentrations of NET were found within two hours after intake of each table. The plasma half life of Net after NET and lyn administration for the period 8-24 h was 8-11 h. No significant difference was found between the half life of NET and the NET tablets and after the lyn tablets. When 5 mg NET was given the plasma half life of NET for the period 24-72 h was around 10 h and this was significantly shorter than the half-life of NET after 5 mg lyn, which was 16 1/2 h. The systemic availability of the drugs was estimated by calculating and comparing the areas under the plasma concentration versus time curve (AUC). 0-24 H. The AUC 0.24 after 0.3 MG NET was almost identical to the AUC 0.24 after 0.5 mg lyn. The AUC 0-24 after 0.5 mg NET was significantly larger than after 0.5 lyn. No difference was found between the AUC 0-24 after 5 mg lyn and 5 mg NET. This study supports the concept of a conversion from lyn to NET. It also shows that there were only minor pharmacokinetic differences between the drugs when all samples were measured as NET.

Administration, Oral↗
PubMed1979

Serum concentrations of estrone, androstenedione, testosterone and sex-hormone-binding globulin in postmenopausal women with breast cancer and in age-matched controls.

The concentrations of estrone (E1), androstenedione (A), testosterone (T) and sex-hormone-binding globulin (SHBG) in the serum were determined in 122 postmenopausal women, unselected with respect to age and stage of disease and with a newly diagnosed breast cancer. The results were compared with those in 122 age-matched women without breast cancer, selected from the population register. The patients were found to have a significantly higher mean level than the controls of E1 (132 and 108 pmol/l), A (2.5 and 1.6 nmol/l) and T (1.54 and 1.38 nmol/l) and a lower level of SHBG (40.2 and 47.3 nmol/l) in the serum. A multiple regression analysis revealed in the control group that the serum level of E1 was significantly correlated to A (r = 0.48, p less than 0.001) and T (r = 0.45, p less than 0.001). In the patient group E1 was only slightly correlated to T (r = 0.25, p less than 0.01) and not to A (r = 0.10, p greater than 0.05). A significant negative correlation was found between SHBG and weight in both groups. Otherwise no significant correlations were found between any of the hormone levels and age, stage of disease of weight. It was concluded that an increased availability of A and T, leading to an increased androgenic stimulation--and therefore decreased SHBG--and an increased E1 level, is the most reasonable explanation for the findings. The lack of correlation between E1 and A in the patient group is however difficult to explain and the results do not seem to fit into a definite hypothesis.

Age Factors↗
PubMed1978

Vaginal progesterone for contraception.

Silastic vaginal rings impregnated with progesterone (P) or progesterone and estradiol (E) were used in nine women for thirty 21-day cycles to study the effect on ovarian function. The average daily rates of release of P and E from the rings were 2.2 mg/day and 220 microgram/day, respectively. In anovulatory treatment cycles the mean plasma level of P was 0.9 ng/ml. E levels fluctuated in the range seen in normally cycling women due to endogenous E production. In a menopausal woman the E levels increased to 50 to 100 pg/ml during treatment and FSH levels declined. Ovulation occurred in 18 (60%) of the treated cycles, and resulted in one pregnancy. Although the results rule out the use of these rings for contraceptive purposes, they indicate that at higher dosages the Silastic vaginal ring offers a mode of administration of natural steroids to be used in hormonal contraception.

Contraceptive Agents, Female↗