Long-acting contraceptive agents: Norethisterone esters of arylcarboxylic acids

The synthesis of esters of norethisterone (17α-ethynyl-17β-hydroxy-estr-4-en-3-one) with acids containing a benzene ring is described, two methods of esterification being compared in terms of yield and convenience. The activities of these esters as long-acting contraceptive agents have been evaluated.     

Poly(DL-lactide-co-glycolide)/norethisterone microcapsules: an injectable biodegradable contraceptive

Microcapsules made from a biocompatible, biodegradable polymeric excipient, poly(DL-lactide-co-glycolide) (DL-PLGA) that contained 22 weight percent (wt %) norethisterone (NET), were prepared by a solvent-evaporation microencapsulation process. The effects of changing both the lactide-to-glycolide ratio of the DL-PLGA and the size of the microcapsules on the rate of NET release and the rate of excipient biodegradation were determined in vivo. NET release rates were determined in baboons after injecting the microcapsule formulations intramuscularly. Serum samples obtained at various times following treatment were analyzed for NET, progesterone, and estrogen by radioimmunoassay (RIA). Biodegradation kinetics were determined by injecting NET microcapsules made from radiolabeled DL-PLGA intramuscularly into the hind legs of rats. Residual radioactivity at the injection site was determined at various times after treatment by combustion analysis of the muscle tissue. Changing the ratio of the comonomers to include more glycolide (DL-lactide:glycolide-96:4, 92:8, 87:13, 74:26) increased the rate of NET release and accelerated the biodegradation of the copolymer excipient. Decreasing the size of the microcapsules increased the rate of NET release. On the basis of these studies a NET microcapsule formulation has been identified for clinical testing which releases NET for 3 months and biodegrades completely within 6 months.     

Return of fertility after use of the injectable contraceptive Depo Provera: up-dated data analysis

796 Thai women who stopped using the long-acting injectable contraceptive depot medroxyprogesterone acetate (DMPA, Depo Povera), 437 women who stopped using oral contraceptives and 125 women who had an IUD removed to have a planned pregnancy, were followed up to ascertain the delay to conception after the end of contraception and to determine the proportion of women who did not conceive in the 4 years after discontinuation. The median delay to conception was 5.5 months plus the estimated duration of the effect of the last injection of DMPA, 3 months for oral contraceptives and 4.5 months after discontinuing the IUD. The proportion of women who did not conceive within 9 months after discontinuation of DMPA is similar to that of ex-IUD users, and by 3 years to that of the ex-pill sample. There is no evidence to suggest that prolonged use of DMPA increases the delay to conception. The return of fertility among never pregnant ex-users resembled that of ever pregnant ex-users. There were comparable proportons of live births among ex-DMPA users and ex-pill users and both of these showed higher proportions of live-births than ex-IUD users. There was no evidence to suggest that previous use of DMPA had any significant adverse effect on the outcome of pregnancy of the subsequent births. This study did not show any association between infertility and the previous use of DMPA or other contraceptives.     

The use of induced abortion as a contraceptive: the case of Mongolia

After the onset of liberlization of the Mongolian economy in 1989, the laws governing abortion were relaxed. Furthermore, the availability and use of modern contraceptives also started to improve. The Demographic Survey of Mongolia, conducted during June-July 1996, collected information on different aspects of abortion. This paper presents the results on the prevalence of induced abortion and other related issues. It was found that in the absence of adequate knowledge and availability of modern contraceptives in Mongolia. the prevalence of induced abortion was relatively high. About 24% of women undergoing abortion were using it as a contraceptive because they thought it to be a safe method of contraception. Though the abortion rules stipulate counselling on the use of modern contraceptives just after an abortion, only 60% of women undergoing an abortion were given such counselling.     

Low dosage progestagen as an oral contraceptive: a clinical study

A low dose of an oral progestagen (norethindrone 0.35 mg. daily) was used as a contraceptive agent in a group of 70 women. The average period of use was 16.7 months; it was over two years in 21 subjects. Eight patients withdrew from the trial because of excessive or irregular bleeding. The incidence of side effects was lower than with the combined type of contraceptive preparations. Of the six pregnancies that occurred, only two could be attributed to failure of the method.     

Oral contraceptive use and venous thromboembolism: absence of an effect of smoking.

We conducted a case-control study to test the hypothesis that women smokers who use oral contraceptives have an increased risk of developing venous thrombosis. Patients and controls were drawn from two sets of hospital patients already included in the Boston Collaborative Drug Surveillance Programme. Sixty patients with uncomplicated thromboembolism were matched with 180 controls with other diagnoses; all were premenopausal women taking oral contraceptives. Patients with conditions that might predispose to thromboembolism or be related to smoking were excluded. We found no association between smoking habits and thromboembolism. Similarly, we found no association between thromboembolism, smoking, and duration of oral contraceptive use. Thus we conclude that differences in fibrinolytic activity between smokers and non-smokers are not major factors in the aetiology of uncomplicated thromboembolism in women using oral contraceptives.     

Reported jealousy differs as a function of menstrual cycle stage and contraceptive pill use: a within-subjects investigation

Previous research suggests that female jealousy is sensitive to hormonal variation and, more specifically, potentially moderated by estrogen levels. Here, we tracked self-reported jealousy using a within-subjects design, comparing jealousy when the same women were regularly cycling and using hormonal contraceptives. Results show that fertile cycle phases are associated with higher levels of jealousy than nonfertile cycle phases in both single and partnered women. However, patterns of jealousy reported when using hormonal contraceptives, as compared to when regularly cycling, differed between single and partnered women. In single women, levels of jealousy while on the pill fell between those reported when fertile and nonfertile but were not significantly different from either. In partnered women, levels of jealousy while using the pill were significantly higher than those reported during the nonfertile cycle phase and similar to those during the brief period of fertility. We discuss possible reasons for differences between single and partnered women in reported jealousy while using the pill. This research is the first to definitively show that a psychological characteristic, for example, jealousy, may be influenced differentially by endogenous hormones vs. exogenous hormones administered via hormonal contraceptives.     

Predicting contraceptive use in Bangladesh: a logistic regression analysis

Family planning knowledge, attitude and practice surveys typically assess respondents' reproductive attitudes and intentions to use contraception. Longitudinal observation of individual respondents nevertheless shows that such questions are not strongly predictive of subsequent behaviour. This study examines 3 years' data which show that a set of such responses to questions are nevertheless substantially superior in predicting behaviour than any single indicator. Thus statistical techniques which bring into account the apparent multidimensionality of contraceptive motivation can greatly improve upon the estimation of future practice of family planning in a population.     

Development of BCG as a live recombinant vector system: potential use as an HIV vaccine.

Bacille Calmette-Guèrin (BCG), a live attenuated tubercle bacillus, is currently the most widely used vaccine in the world. Because of its unique characteristics, including low toxicity, adjuvant potential, and long-lasting immunity, BCG represents a novel vaccine vehicle with which to deliver protective antigens of multiple pathogens. We have developed episomal and integrative expression vectors employing regulatory sequences of major BCG heat shock proteins for stable maintenance and expression of foreign antigens in BCG vaccine strains (22). Shuttle plasmids capable of autonomous replication in Escherichia coli and BCG were constructed with a DNA cassette containing a minimal replicon derived from the Mycobacterium fortuitum plasmid pAL5000. Efficient and stable chromosomal integration of recombinant plasmids into BCG was achieved using a DNA segment containing the mycobacteriophage L5 attachment site and integrase coding sequence. Using the BCG hsp60 and hsp70 stress gene promoters, we were able to express Escherchia coli beta-galactosidase to levels in excess of 10% of total cell protein. The major antigens of HIV-1 gag, pol, and env were also stably expressed using our vector systems. The recombinant BCG elicited long-lasting humoral and cellular immune responses to these antigens in mice. Antibody responses to beta-galactosidase using as few as 200 colony-forming units were detected 6 weeks after immunization, and titers (1:30,000) were sustained for more than 10 weeks. Cellular immune responses, of both cytotoxic T cell (CTL) and helper T lymphocytes, were detected to beta-galactosidase. CTL responses were also induced to the HIV-1 envelope protein. Thus, we have demonstrated stable recombinant antigen expression, processing, and presentation using our recombinant BCG vector system. This live recombinant vector system shows promise as a universally applicable and safe vaccine vehicle for protection against various infectious diseases.     

Ovarian activity reversibility after the use of deslorelin acetate as a short-term contraceptive in domestic queens

The objective was to evaluate ovarian activity reversibility in domestic queens after short-term contraceptive treatment with deslorelin acetate. Ten mature queens were used. In all queens, the estrous cycle was evaluated every 72 h by vaginal cytology (VC) and behavior assessments. When queens had VC characteristic of interestrus or diestrus, one deslorelin acetate implant (4.7 mg) was placed in the subcutaneous tissue of the interscapular region (day of insertion = Day 0). Thereafter, VC was performed every 48 h and on Day 90, implants were removed. At Day 100, estrus and ovulation were induced with 100 IU eCG (im), followed by 100 IU hCG (im), 84 h later (Day 103.5). Queens were ovariohysterectomized on Day 106. Corpora lutea (CL) were counted, oviducts were flushed, and oocytes were identified, isolated and stained to assess viability. In all queens, blood samples for plasma progesterone concentrations were collected once a week, from Days −21 to 106. After deslorelin acetate application, four queens had VC and behavior typical of estrus, and one ovulated. Furthermore, ovulation occurred in three queens that did not have VC or behavior consistent with estrus. After the initial ovarian stimulation, all females had anestrous VC during the deslorelin treatment period. Implants were readily removed. Following implant removal, all females responded to treatments to induce estrus and ovulation. There were (mean ± SEM) 13.1 ± 5.5 CL and 8.1 ± 5.5 oocytes per queen; the oocyte recovery rate was 56.8 ± 25.4% and all recovered oocytes were viable. We concluded that deslorelin acetate can be used as a reversible short-term contraceptive in domestic cats, because estrus and ovulation were successfully induced following implant removal.     

A transformation system for the yeast Candida utilis: use of a modified endogenous ribosomal protein gene as a drug-resistant marker and ribosomal DNA as an integration target for vector DNA.

We have developed a transformation system for the yeast Candida utilis. A novel strategy was applied to construct the transformation system, since auxotrophic mutants which could be used as hosts for transformation are not available. A gene encoding the ribosomal protein L41 was cloned from C. utilis, which is sensitive to cycloheximide, and used as a marker gene conferring cycloheximide resistance after modification of its amino acid sequence. The marker gene was constructed by substitution of the proline codon at position 56 with the glutamine codon by in vitro mutagenesis, as it had been reported previously that the 56th amino acid residue of L41 is responsible for the cycloheximide sensitivity of various organisms (S. Kawai, S. Murao, M. Mochizuki, I. Shibuya, K. Yano, and M. Takagi, J. Bacteriol. 174:254-262 1992). The ribosomal DNA (i.e., DNA coding for rRNA) of C. utilis was also cloned and used as a multiple-copy target for the integration of vector DNA into the genome, which resulted in a high transformation efficiency. Transformants were obtained by electroporation with a maximum efficiency of approximately 1,400 transformants per 1 microgram of linearized DNA carrying the gene for cycloheximide resistance and part of the ribosomal DNA. No transformants were obtained with intact plasmids. Multiple copies of the linearized plasmid were integrated into the host chromosome by homologous recombination. Southern analysis of the transformants in which vector DNA was integrated at the L41 gene locus indicated that there are two copies of gene for the L41 protein per cell, suggesting that C. utilis is diploid. Transformants were obtained from a variety of C. utilis strains, indicating that this method is applicable to the transformation of other C. utilis strains, even though there is significant heterogeneity in chromosomal karyotypes among these strains.     

Determinants of spacing contraceptive use among couples in Mumbai: a male perspective

This study aimed to determine the factors influencing the use of spacing contraceptive methods in India, particularly from men's perspective. Data were obtained through a semi-structured interview schedule from 2,687 married men aged between 18 and 40 years from central Mumbai City, India, during 1999. Chi-squared tests and binary logistic regression analysis was carried out to determine the relationship between various variables and the likelihood of a couple using spacing contraceptive methods. Of the 2,687 couples, 1,395 (51.9%) were using one or other method of spacing contraceptives and 1,292 (48.1%) were not using any method at the time of survey. Male participation in contraceptive use was 23% (condom and withdrawal). The results indicate that the use of spacing contraceptive methods was significantly higher among those couples where the men desired one or two children (OR=4.3), had knowledge of five or more contraceptive methods (OR=1.9) and discussed with their wives obtaining family planning information (OR=3.2), spacing (OR=2.7) and permanent (OR=2) contraceptive methods. Age, income, desired number of children, knowledge of a greater number of contraceptive methods, inter-spouse communication regarding obtaining family planning information, spacing and permanent methods were found to be strong predictors of the use of spacing contraceptive methods. The study underlines the importance of intervention programmes aimed at promoting a small family norm, increasing the number of contraceptive choices available and encouraging inter-spouse communication. Hence, policymakers and programme managers should encourage interventions in this direction, targeting couples to enhance the use of spacing contraceptive methods.     

Effect of child survival on contraceptive use in Bangladesh.

A study in Bangladesh showed that couples who lost a child often stopped practising contraception in order to have another child. Logistic regression analysis revealed that contraceptive continuation was related to maternal age, parity, husband's education and the sex of the last child.     

Clinical study of gossypol as a male contraceptive

Animal experiments conducted in the late 1960s and early 1970s in various institutes of China showed that the effective antifertility agent in crude cottonseed oil was gossypol. Gossypol is a yellow substance which occurs in various parts of the cotton plant; its chemical structure is naphthol phenol. At the Capital Hospital gossypol was tested on 172 volunteers selected from hospital employees and workers from a nearby factory. All of the volunteers were under age 50, married and healthy with at least 1 child. Examinations required before treatment were general physical examination, a blood and urine analysis, an electrocardiogram, serum potassium concentration and serum analysis. 2 stages of gossypol treatment were required in the clinical study: the initial stage, the loading period, is of about 60 days. A daily dose of 20 mg gossypol was given successively for 60 days causing the sperms to become immotile, reduced in number or totally absent. A sperm count below 4 million/ml semen was considered to indicate infertility. The dosage in the 2nd stage, the maintenance period, was reduced to 1/3 of the original dose to maintain infertility. The volunteers were followed up every 2-3 months. Fatigue, decrease of libido and impaired appetite were the 3 main complaints. Serum glutamic-pyruvic transaminase (SGPT) activities showed that the transient symptoms of fatigue and loss of appetite were not related to disturbance of liver function. The mechanism of hypokalemia induced by gossypol is probably of renal origin. Infertility induced by gossypol in contraceptive doses over a relatively short period of administration was reversed about 3 months after stopping treatment. Gossypol used as a male antifertility agent has been found to be very effective and relatively safe.