Inter-varietal sterility and fertility restoration in Oryza sativa Linn.

This study explored the underlining reproductive factors that cause sterility in rice, using hybrids obtained from crosses among landrace selections and improved varieties. The study was carried out between 2016 and 2018. Nine landrace cultivars and two improved varieties were involved in the hybridization experiment. Among the 17 putative hybrids that were obtained, only 5 were confirmed as true hybrids. Meiotic chromosome studies and pollen studies in the F1, and Mendelian segregation studies for fertility in the F2 were carried out. Some F2 lines were monitored to F3 to ascertain the level of fixation of gene combinations for fertility. The results obtained from the chromosomal studies showed that phenomena such as laggards, precocious movements, formation of multivalents, and unequal segregation to the poles are associated with pollen sterility in all - 5 hybrids, at the F1 and F2 generations. The indehiscence of anthers contributed to infertility due to pollen shortage than the fertility of the pollens themselves. Even though in males, there is a preponderance of male sterility, female sterility is also a phenomenon that is possibly contributing to inter-varietal sterility. The segregational pattern of 13:3 was observed for fertility in the F2 which suggests the inhibition of fertility by a gene in the dominant state. There was the restoration of fertility in many of the lines advanced to the F3 to up to 93 % fertility. It was, therefore, concluded from the study that landraces of rice still hold the key for the rice crop improvement and should therefore be conserved.

The Detection of Wolbachia in Tea Green Leafhopper (Empoasca onukii Matsuda) and Its Influence on the Host

Tea green leafhopper (Empoasca onukii Matsuda) is a critical pest in tea production. Wolbachia has attracted much attention as a new direction of pest biological control for its ability of manipulating the hosts’ reproductive biology. In this work, we focused on the detection of Wolbachia in tea green leafhopper and its effect on host reproduction and development. Polymerase chain reaction (PCR), real-time PCR, and fluorescence in situ hybridization (FISH) techniques were used to detect the distribution of Wolbachia in tea green leafhopper. Wolbachia infection levels were different in different organs of hosts in different insect stages. In addition, comparison between the infected populations and cured population (treated by tetracyclines) revealed that presence of Wolbachia apparently influenced the growth, life cycle, and other reproductive factors of tea green leafhopper, caused, for example, by cytoplasmic incompatibility (CI), thereby reducing number of offspring, shortening lifespan, and causing female-biased sex ratio. This research confirmed that the bacteria Wolbachia was of high incidence in tea leafhoppers and could significantly affect the hosts’ reproductive development and evolution.

Association between female reproductive factors and gout: a nationwide population-based cohort study of 1 million postmenopausal women

Background Previous studies have shown that the incidence and risk factors of gout differs according to sex. However, little research has been done on the association between reproductive factors and gout. We conducted an analysis of a large nationwide population-based cohort of postmenopausal women to determine whether there is an association between reproductive factors and the incidence of gout. Methods A total of 1,076,378 postmenopausal women aged 40–69 years who participated in national health screenings in 2009 were included in the study. The outcome was the occurrence of incident gout, which was defined using the ICD-10 code of gout (M10) in the claim database. Cox proportional hazard models were used for the analyses and stratified analyses according to body mass index (BMI) and the presence/absence of chronic kidney disease (CKD) were performed. Results The mean follow-up duration was 8.1 years, and incident cases of gout were 64,052 (incidence rate 7.31 per 1000 person-years). Later menarche, earlier menopause, and a shorter reproductive span were associated with a high risk of gout. No association between parity and gout incidence was observed. Use of oral contraceptives (OC) and hormone replacement therapy (HRT) were associated with an increased risk of gout. The association between reproductive factors and gout was not statistical significant in the high BMI group. The effects of OC and HRT usage on gout were not significant in the CKD group. Conclusion Shorter exposure to endogenous estrogen was associated with a high risk of gout. Conversely, exposure to exogenous estrogen such as OC and HRT was associated with an increased risk of gout.

The distribution of reproductive risk factors disclosed the heterogeneity of receptor-defined breast cancer subtypes among Tanzanian women

Background Recent epidemiological studies suggest that reproductive factors are associated with breast cancer (BC) molecular subtypes. However, these associations have not been thoroughly studied in the African populations. The present study aimed to investigate the prevalence of BC molecular subtypes and assess their association with reproductive factors in Tanzanian BC patients. Methods This hospital-based case-only cross-sectional study consisted of 263 histologically confirmed BC patients in Tanzania. Clinico-pathological data, socio-demographic characteristics, anthropometric measurements, and reproductive risk factors were examined using the Chi-square test and one-way ANOVA. The association among reproductive factors and BC molecular subtypes was analyzed using multinomial logistic regression. The heterogeneity of the associations was assessed using the Wald test. Results We found evident subtype heterogeneity for reproductive factors. We observed that post-menopausal status was more prevalent in luminal-A subtype, while compared to luminal-A subtype, luminal-B and HER-2 enriched subtypes were less likely to be found in post-menopausal women (OR: 0.21, 95%CI 0.10–0.41, p = 0.001; OR: 0.39, 95%CI 0.17–0.89, p = 0.026, respectively). Also, the luminal-B subtype was more likely to be diagnosed in patients aged ≤ 40 years than the luminal-A subtype (OR: 2.80, 95%CI 1.46–5.32, p = 0.002). Women who had their first full-term pregnancy at < 30 years were more likely to be of luminal-B (OR: 2.71, 95%CI 1.18–4.17, p = 0.018), and triple-negative (OR: 2.28, 95%CI 1.02–4.07, p = 0.044) subtypes relative to luminal-A subtype. Furthermore, we observed that breastfeeding might have reduced odds of developing luminal-A, luminal-B and triple-negative subtypes. Women who never breastfed were more likely to be diagnosed with luminal-B and triple-negative subtypes when compared to luminal-A subtype (OR: 0.46, 95%CI 0.22–0.95, p = 0.035; OR: 0.41, 95%CI 0.20–0.85, p = 0.017, respectively). . Conclusion Our results are the first data reporting reproductive factors heterogeneity among BC molecular subtypes in Tanzania. Our findings suggest that breast-feeding may reduce the likelihood of developing luminal-A, luminal-B, and triple-negative subtypes. Meanwhile, the first full-term pregnancy after 30 years of age could increase the chance of developing luminal-A subtype, a highly prevalent subtype in Tanzania. More interventions to promote modifiable risk factors across multiple levels may most successfully reduce BC incidence in Africa.

THE IMPACT OF FORMAL MATERNAL EDUCATION ON CHILD SURVIVAL IN GHANA

Purpose: The purpose of this study is to investigated the impact of formal maternal education on child survival in Ghana using a probit model. Methodology:This study used data from the Ghana Demographic and Health Survey for the period of 1993 to 2008. It is nationally representative sample including urban and rural areas in the 10 regions of Ghana. It looks at trends in demographic and health indicators and is conducted every five years (GSS, 2009). . Findings: Mothers’ education had a positive and significant effect on child survival. In 2003 the probability of a child surviving up to age five increased by 15.4 percentage points for one year increase in mothers’ education, using control variables and 8.9 percentage points for a year increase in mothers’ education, after including socio-economic and reproductive factors of women, which revealed the true partial effect of maternal education. Unique contributions to theory practice and policy: It was observed that socio-economic and reproductive factors of women had an impact as well, hence policy makers should act to improve on these factors in order to complement the effect of formal maternal education to promote child survival in Ghana.

Estimated lifetime risk of venous thromboembolism in men and women in a Danish nationwide cohort: impact of competing risk of death

Incidence of venous thromboembolism (VTE) risk varies by age and sex. Some studies have reported overall higher risk in men, especially when VTEs triggered by female reproductive factors are excluded. However, higher mortality rates in men may have led to overestimation of lifetime VTE risk in men compared with women. Therefore, we estimated the lifetime risk of VTE in men and women in a Danish, nationwide cohort, taking into account the competing risk of death. Within the population of Denmark (> 5 million persons), all first-time VTEs occurring in 1995–2016 were identified from the Danish National Patient Registry covering all Danish hospitals. The cumulative incidences of VTE were estimated in men and women with age as timescale, taking into account the competing risk of death. Estimated lifetime risk was defined as cumulative incidence at age 100. In a simulation study, we excluded the proportion of female cases that could be attributed to reproductive risk factors and re-estimated the cumulative incidence. We identified 123,543 incident VTEs. The cumulative incidence of VTE was 1.9% in women and 1.3% in men at age 50, 4.3% in women and 4.4% in men at age 70, and 9.3% in women and 8.1% in men at age 100. After accounting for VTEs attributed to reproductive factors, the corresponding incidences in women were 1.2% at age 50, 3.2% at age 70, and 8.2% at age 100. In conclusion, the estimated lifetime risk of VTE was slightly higher in women than in men when accounting for competing risk of death. Our simulation study suggested that reproductive risk factors contribute modestly to the estimated lifetime VTE risk in women.