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Biomedical subjects

R T Burkman

Publications and source records attributed to R T Burkman.

At least 19 recordsLinked to original sources
PubMed1992

The metabolic impact of oral contraceptives.

The hormonal components of oral contraceptives exert major effects on plasma lipoprotein metabolism. Estrogens may increase production of plasma triglycerides, leading to increased levels of very low-density lipoproteins, but they may also reduce levels of cholesterol-enriched and potentially atherogenic intermediate- and low-density lipoproteins. Furthermore, estrogens increase levels of high-density lipoproteins (HDLs), particularly the HDL2 subspecies, an effect linked to reduced mortality rates from cardiovascular disease in postmenopausal women receiving hormone replacement therapy. All combination oral contraceptives in use in the United States tend to raise levels of plasma triglycerides, low-density lipoprotein, and HDL3 to varying degrees. In contrast, changes in HDL and HDL2 reflect the combined effects of estrogen dose and relative androgenicity of the progestin component. Although in general, the lipoprotein changes are greater in magnitude with higher dose oral contraceptive preparations, they can be significant in lower dose preparations as well. Oral contraceptives also affect carbohydrate metabolism, primarily through the activity of progestin. Studies have demonstrated insulin resistance, rises in plasma insulin, and relative glucose intolerance by means of curve analysis of glucose tolerance tests. These effects are far less pronounced with lower dose preparations and with formulations using the newer progestins.

Blood Vessels↗
PubMed1992

Existence of multiple peaks in plasma ethinyl estradiol and norethindrone after oral administration of a contraceptive pill.

Previous measurements of plasma ethinyl estradiol (EE2) and norethindrone (NE) over 24 h after oral administration of a contraceptive pill have demonstrated a single steroid peak occurring 1-2 h after pill ingestion, with a gradual decline over the next 22 h. In the present study plasma concentrations of EE2 and NE were measured 0, 0.5, 0.75, 1, 2, 4, 12, and 24 h after oral ingestion of a contraceptive pill containing 35 micrograms EE2 and 1 mg NE at 0, 3, 6, and 9 months of use in 58 normal healthy women. Contrary to previous reports, analysis of the 464 steroid curves (58 subjects x 4 time periods x 2 steroids) revealed the presence of multiple hormone peaks. Two peaks of EE2 were identified in 44.8% of women during the first pill cycle and in 75.9%, 55.2%, and 67.2% of women after 3, 6, and 9 months of pill use. Two hormone peaks of NE were observed in 29.3% of women during the first cycle and in 36.2%, 50%, and 44.8% at 3, 6, and 9 months, respectively. Existence of these multiple peaks at the frequency observed has not previously been reported. Further quantification of the frequency and magnitude of these peaks could be helpful in explaining differences in biological responses associated with pill use.

Adult↗
PubMed1992

Lipid and carbohydrate effects of a new triphasic oral contraceptive containing norgestimate.

Data are reported from the combined results of two studies assessing the lipid and carbohydrate effects of a triphasic preparation of norgestimate and ethinyl estradiol (Ortho TriCyclen, Tri-Cilest) over a 2-year period in 1,783 healthy women. Mean values for serum levels of high-density lipoprotein cholesterol (HDL-C) were increased significantly, with a percent change at 24 months of 13.2. Values for the ratio of low-density lipoprotein cholesterol to HDL-C were reduced throughout the study period (mean change of -6.4% at cycle 24). There were no clinically significant changes in fasting blood glucose levels or insulin levels or in values for glycosylated hemoglobin. These results are consistent with those of previous studies and indicate that the triphasic preparation of norgestimate and etinyl estradiol is a selective and minimally androgenic oral contraceptive agent. Long-term therapeutic benefit may accrue from the favorable influences on the lipid profile.

Adolescent↗
PubMed1991

The effect of tetracycline on levels of oral contraceptives.

Despite the widespread use of tetracycline for treatment of dermatologic disorders and sexually transmitted diseases, the pharmacodynamics of oral contraceptive use in the presence of tetracycline has not been studied. Seven normal women ingested an oral contraceptive containing ethinyl estradiol 35 micrograms and norethindrone 1 mg in the follicular phase of the menstrual cycle. On day 0 baseline ethinyl estradiol and norethindrone levels were obtained at 0, 1/2, 3/4, 1, 2, 4, 12, and 24 hours after oral contraceptive administration. On day 1 tetracycline 500 mg was given orally every 6 hours while the oral contraceptive was continued. Tetracycline, ethinyl estradiol, and norethindrone levels were determined at the same time intervals as on day 0. Oral contraceptive and tetracycline were continued for up to 10 days, and additional concentrations of ethinyl estradiol, norethindrone, and tetracycline were determined between days 5 and 10. Four additional normal women ingested tetracycline for 5 to 10 days. Tetracycline levels were determined at the time intervals noted above on day 1 and days 5 to 10. No significant decrease in plasma ethinyl estradiol or norethindrone concentration was seen with either short-term (24 hours) or long-term (5 to 10 days) ingestion of tetracycline. Similarly, levels of tetracycline do not significantly decrease with ingestion of a low-dose oral contraceptive.

Adolescent↗
PubMed1991

Oral contraceptives and antithrombin III: variations by dosage and ABO blood group.

A randomized clinical trial of oral contraceptives evaluated 67 women on a regimen of 50 micrograms ethinyl estradiol and 1.0 mg norethindrone, 61 women on a regimen of 35 micrograms ethinyl estradiol and 1.0 mg norethindrone, and 64 women on a regimen of 35 micrograms ethinyl estradiol and 0.5 mg norethindrone. ABO blood group type was determined in all women. At baseline and at 3, 6, and 9 months, plasma antithrombin III levels, by both an immunologic and an activity method, and selected plasma levels of the contraceptive steroids were measured. Antithrombin III levels for all oral contraceptive groups combined decreased from baseline by 19.7% and 28.8% for the immunologic and activity methods, respectively. Analysis of interrelationships among antithrombin III by activity method, oral contraceptive type, and ABO blood group showed larger declines in antithrombin III for type O women using the highest estrogen dose preparation (31.6%) and for non-type O women using the lowest progestin dose preparation (38.9%). Plasma levels of contraceptive steroids also were related to changes in the most extreme levels of antithrombin III.

ABO Blood-Group System↗
PubMed1991

Intrauterine devices.

Approximately 60 million women use the intrauterine device (IUD) worldwide; however, owing primarily to nonmedical reasons, the IUD is far less popular in the United States. Although the contraceptive mechanism of action is unknown, it appears that spermicidal activity may be important. Overall, the efficacy of the copper devices is quite good, such that the overall lifespan can probably be extended. Possible pelvic infection remains the greatest potential risk, although in properly selected women the risk is quite low. Use of prophylactic antibiotics at the time of insertion may offer additional protection against this risk. Although IUD users may have more nonspecific vaginal inflammation than do other women, the clinical significance is probably limited. Further, users do not appear to have elevated risks for cervical infections. Although menometrorrhagia persists as a potential problem, the mechanism for such bleeding is not well understood. Finally, the retroflexed uterine position does not appear to increase the risk of abnormal outcomes.

Female↗
PubMed1991

Strategies for reducing cardiovascular risk in women.

The major risk factors for coronary heart disease in women are much the same as in men. They include elevated cholesterol, hypertension, diabetes, cigarette smoking, severe obesity, a history of stroke and/or thromboembolic disease, and a family history of premature coronary heart disease. Diabetes appears to confer a greater risk and hypertension to have a lesser effect in women than in men. The obstetrician-gynecologist's role as primary care physician is important in terms of risk reduction counseling in areas that are amenable to change: diet, exercise and cigarette smoking. A fourth area, prescribing hormonal therapy, including oral contraceptives and hormone replacement, is the one risk reduction modality that is within the physician's control.

Adolescent↗
PubMed1990

Modern trends in contraception.

Substantial improvements have been made in oral contraceptives, a new injectable contraceptive (Norplant), and the intrauterine device (IUD). Major risks with oral contraceptives have declined substantially, and a number of noncontraceptive health benefits have been discovered. Norplant is probably the first new contraceptive in recent years, and offers long-term contraception with high efficacy and modest risks. The IUD, by carefully selecting users, is a safe and efficacious contraceptive method. The major risk, pelvic inflammatory disease (PID), is far less common if one avoids use in the presence of risk factors for PID.

Contraceptive Agents, Female↗
PubMed1990

Effect of low-dose oral contraceptive on gonadotropins, androgens, and sex hormone binding globulin in nonhirsute women.

The effectiveness of a low-dose oral contraceptive (OC) in suppressing plasma levels of gonadotropins, ovarian, and adrenal androgens and stimulating sex hormone-binding globulin (SHBG) was evaluated prospectively in nonhirsute women. Thirty-three women ingested 35 micrograms of ethinyl estradiol and 1 mg of norethindrone beginning within day 1 to 5 of the menstrual cycle. Baseline levels of luteinizing hormone, follicle-stimulating hormone, total testosterone (T), androstenedione (A), dehydroepiandrosterone sulfate (DHEAS), and SHBG were obtained before ingestion of the OC and repeated after 3, 6 and, 9 months of OC use on day 1 to 5 of the OC "cycle". A significant suppression of gonadotropin levels is seen in nonhirsute women. Sex hormone binding globulin is consistently stimulated by the low-dose OC. A significant suppression of T and DHEAS is observed. No change was seen in levels of A. The demonstrated effects become evident at 3 months and are maintained at 6 and 9 months.

Adolescent↗
PubMed1989

Oral contraceptives and lipids and lipoproteins: Part II--Relationship to plasma steroid levels and outlier status.

A randomized clinical trial of oral contraceptives evaluated 67 women on 50 ug ethinyl estradiol (EE) and 1.0 mg norethindrone (NE), 61 women on 35 ug EE and 1.0 mg NE, and 64 women on 35 ug EE and 0.5 mg NE. At baseline, three, six and nine months, lipids and lipoproteins were measured as well as selected plasma determinations of the contraceptive steroids. Data was related to change in outlier status for lipids/lipoproteins (less than 10th percentile for high-density lipoprotein cholesterol and apolipoprotein A-1, greater than 90th percentile for all others). Women on the lowest dose preparation had the smallest trend towards outlier status for high-density lipoprotein cholesterol and apolipoprotein A-1. An increase over the time period of the study in the initial slope (one hour level minus zero hour level over time) of NE and a decrease in the initial slope of EE was associated with a shift to outlier status for low-density lipoprotein cholesterol. A number of other relationships were also shown. Use of the techniques described might assist in identifying sub-groups of women at risk for adverse cardiovascular sequelae associated with oral contraceptive use.

Adolescent↗
PubMed1989

Oral contraceptives and lipids and lipoproteins: Part I--Variations in mean levels by oral contraceptive type.

A randomized clinical trial of oral contraceptives evaluated 67 women on 50 micrograms ethinyl estradiol (EE) and 1.0 mg norethindrone (NE), 61 women on 35 micrograms EE and 1.0 mg NE, and 64 women on 35 micrograms EE and 0.5 mg NE. Fasting lipids and lipoproteins were measured at baseline, three, six and nine months. All groups showed an increase in plasma total cholesterol, triglycerides, low-density lipoprotein/apolipoprotein B and apolipoprotein A-1. The group taking the preparation with 0.5 mg of NE was the only one to result in an elevation of high-density lipoprotein cholesterol; the other two groups showed declines in the mean levels of this lipoprotein over the study time period. Mean changes in lipid/lipoprotein levels associated with oral contraceptive use appear to be at least partially related to the doses of the contraceptive steroids.

Adolescent↗
PubMed1989

Noncontraceptive clinical benefits of oral contraceptives.

The contraceptive benefits of oral contraceptives have become well known since the introduction of this birth control method in the 1960s. Since that time, a more sophisticated understanding of the hormonal components of the medication has developed, along with reduction in the dosages of these hormones. During the past decade in particular, the medical literature has documented a number of noncontraceptive benefits delineated by studies conducted in Europe and the United States. Users of oral contraceptives have reduced rates of both endometrial and ovarian cancer, and this protection persists even when oral contraceptive use is discontinued. The risk of ectopic pregnancy is reduced up to tenfold among oral contraceptive users and the risk of pelvic inflammatory disease (salpingitis), two- to fourfold. The necessity for performing surgical excision of benign breast cysts or functional ovarian cysts is substantially reduced in women who take oral contraceptives. There also is evidence that the risk of rheumatoid arthritis is reduced in oral contraceptive users. Finally, women who take oral contraceptives have less menstrual dysfunction, such as menorrhagia and dysmenorrhea, than do nonusers. In the United States, it has been estimated that as many as 50,000 hospital admissions are prevented annually because of the noncontraceptive benefits of these drugs. Accordingly, these benefits should be taken into account when discussing contraceptive methods with patients.

Adult↗
PubMed1988

Obesity, stress, and smoking: their role as cardiovascular risk factors in women.

Obesity, defined as an increase of 20% or more above desired weight, has been found to be an independent, albeit weak, risk factor for coronary heart disease in women and may increase the relative risk of other factors such as hypertension, diabetes mellitus, and elevated total serum cholesterol and low-density lipoprotein-cholesterol. Type A personality and stress, on the other hand, appear to be moderate risk factors for coronary heart disease in women as well as in men. Approximately twice as many cardiovascular events occurred in type A women 35 to 64 years old as in type B women of the same age group. As expected, cigarette smoking is a major risk factor, primarily in young women. Women with smoking patterns similar to those of men experience similar rates of cardiovascular morbidity and mortality. In addition, smoking apparently acts synergistically with oral contraceptives and elevated total serum cholesterol to further increase risk.

Adult↗
PubMed1988

Ectopic pregnancy and prior induced abortion.

As part of the Women's Health Study, a case-control study conducted in nine cities in the United States, women hospitalized with an ectopic pregnancy and women hospitalized with non-gynecologic, medical or surgical diagnoses were interviewed concerning past reproductive history. There were 462 women meeting eligibility criteria in the ectopic pregnancy case group and 2326 women meeting the criteria for the control group. After adjustment for a number of possible confounders, the relative risk of ectopic pregnancy for women with a history of one induced abortion was 1.0 (95% confidence limits: 0.5 to 1.8) and was 0.9 (95% confidence limits: 0.8 to 1.1) for women with a history of two or more prior induced abortions. These results suggest that prior induced abortion does not significantly increase the risk of subsequent ectopic pregnancy.

Abortion, Induced↗
PubMed1988

The interaction of alcohol consumption and oral contraceptive use on lipids and lipoproteins.

Oral contraceptive (OC) use and alcohol consumption have been shown to alter the levels of lipids and lipoproteins in the blood. The effect of alcohol consumption on levels of total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, LDL-B, Apo-A1, the ratio of HDL cholesterol/total cholesterol, HDL cholesterol/LDL cholesterol, and the ratio of LDL cholesterol/LDL-B among normal healthy young women before initiation of oral contraceptives and after six months of oral contraceptive use are both described. Of primary interest is the mediating effect of alcohol consumption on the association between steroid usage and blood lipid values. At baseline, ethanol consumption was found to be positively associated with triglycerides, HDL-C, and Apo-A1 and negatively associated with LDL-C/LDL-B. After adjustment for several covariables, alcohol consumption was found to be positively associated with the increases in triglycerides and in Apo-A1 observed at 3 and 6 months after initiation of OCs. Since these two parameters are believed to have opposite relationships to cardiovascular disease, the effect of alcohol consumption remains uncertain.

Adult↗