Some characteristics of pollen wall cytochemistry and ultrastructure in Japanese larch (Larix leptolepis Gord.)

Summary The mature pollen of Larix leptolepis Gord. (Conifer) contains five different cell types, and the plasma membrane of the vegetative cell is continuous and organized. The pollen wall is composed of two morphologically and cytochemically distinct domains: the exine and the intine. In the multilayered exine, the ektexine appears granular and the endexine, lamellar. The intine is thick and bilayered with a microfibrillar structure occupying its inner portion. Cytochemical reactions of the exine and the intine are similar to those found in angiosperms. Pollen wall involvement in the male female recognition system is discussed with respecl to the angiosperms.     

Interspecific incompatibility in Populus: inhibition of tube growth and behaviour of the male germ unit inP. deltoides×P. alba cross

Summary In order to better understand the cellular events controlling interspecific incompatibility in the genus Populus, the incompatible cross betweenP. deltoides andP. alba has been investigated both at the light and electron microscopic levels. Stained in decolourized aniline blue and observed by epifluorescence microscopy, most incompatible pollen grains are seen to germinate at the stigma surface. Numerous incompatible pollen tubes reach the base of the style where they are arrested 19 h after pollination. Ultrastructural observations on in vivo growing incompatible pollen tubes confirm these data. Very few cytoplasmic modifications are seen within living pollen tubes reaching the lower end of the style or within arrested ones, except the presence of polymorphic plastids. In this predominantly tricellular system, the male germ unit (MGU) is apparently initiated at pollen maturity as an association between the vegetative nucleus and sperm cells. It is maintained during pollen tube growth within the style and persists within arrested incompatible pollen tubes. The unique observation of an association between a dividing generative cell at metaphase and the vegetative nucleus is also reported. Arrested pollen tubes are characterized by apical deformations and accumulation of callose within their thickened cell walls. These cytological data provide additional information on the cellular events associated with interspecific incompatibility in Populus.Abbreviations DAPI 4,6-diamino-2-phenylindole - FCR fluorochromatic reaction - MGU male germ unit     

Integrating Cervical Cancer Screening with HIV Care in Cameroon: Comparative Risk Analysis of Cervical Disease in HIV-Infected Women Receiving Antiretroviral Therapy to Women in the General Population

Background

While the effect of highly active antiretroviral therapy (HAART) on natural history of cervical lesions remains controversial, resource limited countries need to understand the relevance of their own data to their settings. We compared the risk of cervical disease in HAART-experienced women with that in women in the general population of Cameroon.

Methods

A retrospective cross sectional survey of women aged 35 years and above, attending a voluntary screening campaign for cervical cancer at the Nkongsamba Regional Hospital in Cameroon between February and May 2014. Squamous intraepithelial lesions (SIL) were determined by Pap smear. Multiple logistic regression was used to compare the odds of SIL in women on HAART to women from the community with unknown HIV status.

Results

Included were 302 women of whom 131(43.4%) were HIV-infected and receiving HAART on the site while 171 (56.6%) were women from the community. Cervical disease was observed in 51(16.9%) persons of whom 15 (11.5%) cases in the HAART group and 36 (21.1%) cases in the general group (p = 0.027). After controlling for age and other covariates, women in the HAART group had a 67% reduction in the odds of cervical lesions compared with the community group [adjusted odd ratio (aOR) = 0.33, 95%CI: 0.15–0.73, p = 0.006).

Conclusion

HIV-infected women receiving HAART have a lower risk of cancer than women in the general population. This finding may not be attributed to HAART alone but to all the health benefits derived from receiving a comprehensive HIV care.