Roger V. Short

Mammalian mitogenomic relationships and the root of the eutherian tree.

The strict orthology of mitochondrial (mt) coding sequences has promoted their use in phylogenetic analyses at different levels. Here we present the results of a mitogenomic study (i.e., analysis based on the set of protein-coding genes from complete mt genomes) of 60 mammalian species. This number includes 11 new mt genomes. The sampling comprises all but one of the traditional eutherian orders. The previously unrepresented order Dermoptera (flying lemurs) fell within Primates as the sister group of Anthropoidea, making Primates paraphyletic. This relationship was strongly supported. Lipotyphla (“insectivores”) split into three distinct lineages: Erinaceomorpha, Tenrecomorpha, and Soricomorpha. Erinaceomorpha was the basal eutherian lineage. Sirenia (dugong) and Macroscelidea (elephant shrew) fell within the African clade. Pholidota (pangolin) joined the Cetferungulata as the sister group of Carnivora. The analyses identified monophyletic Pinnipedia with Otariidae (sea lions, fur seals) and Odobenidae (walruses) as sister groups to the exclusion of Phocidae (true seals).

Successful Intra- and Interspecific Male Germ Cell Transplantation in the Rat

Abstract The lumen of the seminiferous tubules has hitherto been regarded as an immunologically privileged site. We report here the birth of young following transplantation of stem spermatogonia from Long-Evans rats to the seminiferous tubules of Sprague-Dawley rats after treatment with the immunosuppressive agent cyclosporin. Follicle-stimulating hormone was also given to stimulate Sertoli cell proliferation, and testosterone to stimulate the recovery of spermatogenesis. Donor germ cells underwent normal spermatogenesis, and progeny were repeatedly produced from the donor germ cells as demonstrated by microsatellite paternity analysis. In addition, donor germ cells from the cryptorchid testes of LacZ mice were also able to colonize the seminiferous tubules of Sprague-Dawley rats using this protocol. Morphologically normal rat and mouse spermatozoa were present in the epididymis and vas deferens of the recipient rats. This highlights the potential for transplantation of male germ cells between different species.

The resumption of ovulation and menstruation in a well-nourished population of women breastfeeding for an extended period of time*

We have studied a large group of Australian women breastfeeding for an extended period of time to determine the duration of lactational anovulation (n = 89) and amenorrhea (n = 101). Salivary progesterone assays were used to determine ovulation. These women had a mean of 322 days of anovulation and 289 days amenorrhea. Less than 20% had ovulated and less than 25% had menstruated by 6 months postpartum. The latest ovulation was at 750 days and the latest menstruation at 698 days. There was no significant correlation between any measure of maternal nutritional status and the duration of anovulation or amenorrhea. Neither the time of first supplement introduction to the baby nor the amount of supplement given was an accurate predictor of the return of ovulation or menstruation. However, our results clearly show that lactational amenorrhea can provide good protection against pregnancy in the 1st 6 months postpartum, even in well-nourished women who are giving their babies supplemental feeds.

Use of dizygotic to monozygotic twinning ratio as a measure of fertility

BACKGROUND Monozygotic (Mz, identical) twinning occurs at a rate of around three per 1000 maternities in all populations, whereas dizygotic (Dz, fraternal) twinning is highly heritable, and varies with age and race. The Dz/Mz twinning ratio reflects the frequency of twin ovulations, and can provide a useful measure of human fertility. METHODS 1625 pairs of twins of known sex were born in Isan Yuk Obstetric Hospital in Hong Kong during the period 1960-95. The yearly Dz/Mz ratio was calculated, and trends were analysed by chi 2 test with the Bonferroni correction. Ages of mothers of all opposite-sexed twins were recorded and trends analysed by ANOVA and linear regression. FINDINGS The Dz/Mz ratio declined significantly from 1.12 in 1960 to 0.05 in 1978 (p < 0.001), and then rose significantly to an average of 0.86 in 1994-95 (p < 0.003). There was a significant declining trend in age of mothers of opposite-sexed twins from 1960 to 1978 (p < 0.001), but there were no significant changes in maternal age after 1978 (p = 0.38). INTERPRETATION If we are correct in assuming that the frequency of Mz twinning remained constant during the study period, the declining Dz/Mz ratio from 1960 to 1978, which also occurred in many developed countries, could reflect some adverse environmental effect on human fertility. The increasing proportion of Dz twins in the past two decades is probably due to increasing use of ovulation-inducing drugs such as clomiphene citrate, which could mask a serious and continuing decline in human fertility. It is therefore important to continue to monitor the Dz/Mz ratio in the future in this and other subpopulations, after exclusion of any women who have taken drugs that stimulate fertility.

New ways of preventing HIV infection: thinking simply, simply thinking

HIV infection is the greatest health crisis in human history. It continues to spread unchecked among the poor in the developing world because we have failed to design simple preventative methods that are available and affordable to those living on under

How Oestrogen or Progesterone might Change a woman's susceptibility to HIV-1 infection

2 a day. Five new methods are discussed. (i) A natural microbicide. Intravaginal lime or lemon juice has been used for centuries as a traditional contraceptive. The juice can also kill HIV in the laboratory, but clinical trials are needed to see if vaginal application is acceptable, safe and effective. (ii) Intravaginal oestrogen. Monkeys can be protected from Simian immunodeficiency virus (SIV) infection by keratinizing the vagina with topical oestrogen. If women take the oral contraceptive pill vaginally it retains its contraceptive efficacy, and the oestrogen it contains should thicken the vagina and protect against HIV infection. Clinical trials are needed. (iii) Male circumcision. Removal of the inner foreskin removes the main site of HIV entry into the penis, resulting in a sevenfold reduction in susceptibility to infection. The practice needs to be promoted. (iv) Post-coital penile hygiene. Wiping the penis immediately after intercourse with lime or lemon juice or vinegar should kill the virus before it has had a chance to infect. A clinical trial of efficacy is needed. (v) PhotoVoice. Asking schoolchildren in developing countries to photograph their impressions of HIV/AIDS is a powerful way of getting them to discuss the subject openly, and develop their own preventative strategies.

Premature introduction of progestin-only contraceptive methods during lactation

Worldwide, 18.5 million women are infected with the human immunodeficiency virus (HIV‐1). At least 80% of these HIV infections have occurred as a result of sexual intercourse with an infected male partner. This review focuses on how HIV‐1 enters the human female reproductive tract, and how oestrogen or progesterone, by altering the cervicovaginal epithelium, might change a womans susceptibility to HIV infection.

Prevalence of HIV and other sexually transmissible infections in relation to lemon or lime juice douching among female sex workers in Jos, Nigeria

Experts on contraceptive technology concur that progestin-only methods can be used safely during lactation. However, very few studies exist of the effects on lactation of the introduction of progestin-only methods prior to the sixth postpartum week. Since progesterone withdrawal is the likely stimulus that initiates lactogenesis, it appears necessary for natural progesterone levels to decline to baseline before a progestin-only contraceptive is initiated. Therefore, the use of such contraceptive methods should be delayed for at least 3 days after the birth. Non-hormonal methods remain the first choice category of contraceptive methods for breastfeeding women, since there is no possibility that they will interfere with lactation. Progestin-only methods comprise a viable and often desirable next choice category, although the timing of their commencement must be determined with care in order to support lactation.

Different fate of primordial germ cells and gonocytes following transplantation.

BACKGROUND The rates of sexually transmissible infections (STI), including HIV, are high among female sex workers (FSW) in Nigeria and the use of various local vaginal cleansing agents to prevent infection is a common practice. The present study was aimed at determining whether any association exists between current lime or lemon douching and the prevalence of STI and HIV infections among FSW in Jos, Nigeria. METHODS Consenting FSW who were users of lemon or lime (UL) or non-users (NUL) were recruited for the study between May and September 2006. A structured questionnaire was administered by trained counsellors. Pre-HIV test counselling was done. Participants blood samples were tested for HIV and syphilis. Genital examination was done and high vaginal and endocervical samples were collected. The samples obtained were processed for STI using standard laboratory procedures. FSW found with treatable STI received free drugs. HIV results were disclosed after post-test counselling and positive FSW were referred to a HIV/AIDS facility for care, support and antiretroviral therapy. RESULTS A total of 398 FSW (86 UL and 312 NUL) participated in the study. Their mean age was 27.6+/-7.0 years (range 16-63 years). HIV prevalence was high for both UL and NUL: 48.8 and 48.2%, respectively (odds ratio 1.0; 95% confidence interval 0.6-1.2, P=0.9427). The rates of bacterial vaginosis were not significantly higher in UL (UL 55.8%, NUL 44.0%, odds ratio 1.59, 95% confidence interval 0.96-2.65, P=0.06). There were no associations between the use of citrus douching and other STI. CONCLUSION There were no significant associations between the prevalence of STI and HIV and lime or lemon juice usage.

Foetal age determination and development in elephants

We have previously demonstrated that both donor primordial germ cells (PGCs) and gonocytes are capable of establishing spermatogenesis in the lumen of the seminiferous tubules of an adult host following transplantation in rats. Here we show that the PGCs, either in crude suspensions or after purification, undergo spermatogenesis only in the intraluminal compartment of the hosts seminiferous tubules, while 4–5 days postpartum gonocytes also interdigitate with the hosts seminiferous epithelium. The donor seminiferous epithelium was always in synchrony with the cycles of the hosts spermatogenesis. It seems that the pattern of spermatogenesis of donor germ cells following transplantation in terms of its spacial location and the connection with the hosts seminiferous epithelium depends on their developmental stages at transfer.