Ingestion of toxic Microcystis aeruginosa by dairy cattle and the implications for microcystin contamination of milk.

Microcystin (MCYST) toxins can be produced by the bloom-forming cyanobacterium Microcystis aeruginosa. They are chemically stable compounds and have both acute and chronic effects on the health of mammals, including cattle and humans. Cattle will drink water containing lethal cell concentrations of M. aeruginosa. When cattle consume sub-lethal doses of microcystins, the fate of those toxins is unknown. We provided drinking water containing 1 x 10(5) cells ml(-1) M. aeruginosa (strain MASH01-A19) to four lactating Holstein-Friesian dairy cattle for 21 days to determine if MCYST-LR produced by the cyanobacteria, could be detected in milk produced by the cattle. Cattle consumed up to 15 mg MCYST-LR at an ingestion rate of 1.21 microg kg (live weight) d(-1). Analysis by HPLC and ELISA indicated that no detectable amounts of microcystin from the cyanobacteria were present in the milk obtained from the treated animals. Based on the level of quantitation of the ELISA analyses, the maximum possible concentration in the milk was less than 2 ng l(-1). This is more than three orders of magnitude less that the concentration that could be considered problematic for milk of 0.86 microg l(-1) which we calculated using the World Health Organization derived tolerable daily intake for MCYST-LR and the per capita daily consumption of milk in Australia.

Sequential addition of low dose of medrogestone or medroxyprogesterone acetate to transdermal estradiol: a pilot study on their influence on the endometrium.

We evaluated bleeding pattern and endometrium following the administration of two of the most common types of progestogens used in hormone replacement therapy, medroxyprogesterone acetate (MPA) and medrogestone acetate. Twenty eight patients in spontaneous menopause were randomly allocated to two groups. Group 1 (n = 14) received 5 mg/day of of MPA and group 2 (n = 14) received 5 mg/day of medrogestone: both the progestogens were sequentially added for the last 12 days of a 21-day period of transdermal estradiol administration (50 micrograms per day). A 7-day treatment-free period completed the cycle. The study treatments were administered for 6 cycles. The endomtria were checked for their thickness by transvaginal ultrasound before starting treatment and at 6th treatment cycle (days 6-10 of the estrogen-only phase and during the period between days 8 and 12 of the progestogen addition). Endometrial biopsies were performed before starting treatment only in the patients with a positive progesterone challenge test and in all the patients at the end of the study during the addition of the progestogen. The bleeding pattern was closely monitored. MPA is accompanied by a thick endometrium with full secretory transformation in all cases. On the contrary, the same dose of medrogestone induced a consistent decrease of estrogen primed endometrium with only 4 cases of full secretory transformation. Four medrogestone-treated patients dropped out due to unscheduled bleeding. A low dose of medrogestone added to transdermal estradiol induced incomplete transformation of endometrium and oligo-amenorrhea more frequently than MPA, but it increased the chances of irregular bleeding. MPA fully transformed the endometrium: periods were thus heavier but regular. None of the patients in either group had endometrial hyperplasia.

Combined use of progesterone challenge test and endometrium thickness evaluated by transvaginal ultrasonography in the preventive management of postmenopausal women.

Endometrial thickness was evaluated in apparently normal postmenopausal women by transvaginal ultrasonography and the results were compared with the response to the progesterone challenge test (PCT). A positive correlation between amount of withdrawal bleeding after PCT and endometrial thickness was found, also demonstrated by the significative correlation between bleeding length and endometrial thickness. Among women referring withdrawal bleeding, 100 and 22% of cases classified as overt flow and spotting, respectively, were characterized by pathologic histological findings. The combined use of these two procedures is suggested as an effective screening mean in the preventive endometrial management of apparently normal postmenopausal women to select candidates for diagnostic invasive procedures.