The mac1 mutation alters the developmental fate of the hypodermal cells and their cellular progeny in the maize anther.

In angiosperm ovules and anthers, the hypodermal cell layer provides the progenitors of meiocytes. We have previously reported that the multiple archesporial cells1 (mac1) mutation identifies a gene that plays an important role in the switch of the hypodermal cells from the vegetative pathway to the meiotic (sporogenous) pathway in maize ovules. Here we report that the mac1 mutation alters the developmental fate of the hypodermal cells of the maize anther. In a normal anther a hypodermal cell divides periclinally with the inner cell giving rise to the sporogenous archesporial cells while the outer cell, together with adjacent cells, forms the primary parietal layer. The cells of the parietal layer then undergo two cycles of periclinal divisions to give rise to three wall layers. In mac1 anthers the primary parietal layer usually fails to divide periclinally so that the three wall layers do not form, while the archesporial cells divide excessively and most fail to form microsporocytes. The centrally located mutant microsporocytes are abnormal in appearance and in callose distribution and they fail to proceed through meiosis. These failures in development and function appear to reflect the failure of mac1 gene function in the hypodermal cells and their cellular progeny.

[A program to instruct women in breast self-examination]. / Programma obucheniia zhenshchin samoobsledovaniiu molochnykh zhelez.

The study was concerned with analysis of the second stage of evaluation of a breast self-examination training program aimed at early detection of cancer. A total of 60,079 of women were recruited into the WHO/USSR Project in Moscow in 1985-1988: study group--30,465 and controls--29,614. At 6 months, 52.5% of women performed breast self-examination on a regular basis whereas at 12 months the percentage decreased to 42.0. Breast cancer was diagnosed in 6 out of 11,548 females of the study group (stage I--1 case, stage II--3 and stage III--2 cases) and in 10 out of 23,083 controls (stage I--2, stage II--5, stage III--2 and stage IV--1 patient). In the study group, medical advice was sought 4.5 times more frequently than in controls.

[Carcinogenic and nonspecific harmful factors in the rubber industry]. / Kantserogennye i nespetsificheskie povrezhdaiushchie faktory v proizvodstve reziny.

The hygienic analysis of working conditions at a rubber production plant revealed that measures aimed at the decrease of dust load of the preparatory process were not sufficient. High dust load was accompanied by unfavourable microclimatic conditions. The content of carcinogens, such as benz(a)--pyrene, acrylonitrile, and vinyl chloride on the average did not exceed MACs. Their highest concentrations exceeding MACs were detected in vulcanization and compaction bays. Preventive measures should be directed at reducing workers' exposure to carcinogens and nonspecific occupational damaging factors by means of automatization and hermetic sealing of the equipment along with the introduction of robotized systems.