NHMRC workshop on non-pharmacological methods of lowering blood pressure. The role of physical activity.

Cross-sectional studies have demonstrated a negative association between the reported level of leisure-time activity, measured endurance fitness, and blood pressure. There have also been a number of prospective trials; the majority indicate that an increase in fitness is followed by a fall in blood pressure. Few have included control subjects--a critical defect, since a spontaneous fall in blood pressure is customary with serial measurements in individuals. The studies which did have control subjects were examined in detail. These also generally indicated a lowering of blood pressure with increasing fitness. However, other flaws in design of these studies, such as a lack of blind assessment, prohibit confident conclusions. There is a need for further randomized, controlled, single-blind trials concerning the relationship between physical activity and blood pressure.

Amplification of DNA sequences in polar bodies from human oocytes for diagnosis of mitochondrial disease.

When a preovulatory oocyte reinitiates meiosis, it sheds a cytoplasmic fragment containing mitochondria and a redundant set of chromosomes. We have detected DNA sequences from both the mitochondrial and nuclear genomes in polar bodies from unfertilised human oocytes, demonstrating the feasibility of diagnosing mitochondrial diseases before conception.

Transferrin in the developing ovarian follicle: evidence for de-novo expression by granulosa cells.

Transferrin is produced primarily by the liver and is best known as a carrier of iron in the circulation. Transferrin is also produced extra-hepatically where it may serve to suppress the generation of reactive oxygen species and act as a growth factor, in addition to its role in the endocytosis of iron. There is evidence that transferrin and its cognate receptor are important for successful development of follicles but little is known about their precise roles in this context. To learn more about their modus operandi, we undertook immunocytochemical studies which revealed that transferrin and its receptor are distributed heterogeneously in human granulosa cells, with more pronounced expression in more mature follicles. Expression within the oocyte itself was not prominent until the antral stage of development. Using nested reverse trancription-polymerase chain reaction (RT-PCR), transferrin mRNA expression was demonstrated in granulosa cells of the human and mouse ovary but not in the oocyte. Hence it appears that local production of transferrin is possible in addition to the likely uptake of circulating protein into the follicle by endocytosis. Values of transferrin in the follicular fluid were found to be highly correlated with those in serum, suggesting that the small contribution made by its localized synthesis in the granulosa cell may be important for some as yet unknown mechanism in follicle maturation.