Differential effect of zinc on teratogen-induced inhibition of pinocytosis by cultured rat yolk sac

Pinocytosis as measured by the uptake of 125I labelled PVP by the isolated cultured day 12 rat yolk sac was observed to be linear over a 4 h incubation period and to proceed at a rate of approximately 2.5 microliters/mg protein/h. Cadmium, anti-visceral yolk sac antibody (AVYS) and trypan blue all inhibited pinocytosis in a concentration-dependent fashion when added to the culture medium, although at low concentrations trypan blue was slightly stimulatory. The effect of zinc on the inhibition of pinocytosis by these three teratogens was studied. It was observed that zinc ameliorated the inhibitory effects of cadmium and AVYS, but had no effect on inhibition by trypan blue. These results indicate that the previously demonstrated protective action of zinc against cadmium-induced yolk sac dysfunction is not specific to that agent but extends to inhibition of pinocytosis by AVYS, and further suggest that, because of its refractoriness to zinc, trypan blue-induced inhibition of pinocytosis by yolk sac occurs by a mechanism different from that effected by cadmium and AVYS.     

Clearance of bacteria and non-antigenic markers following intra-uterine inoculation into maiden mares: Effect of steroid hormone environment

Uterine response to inoculation with Streptococcus zooepidemicus organisms (antigenic markers) and 15-mum microspheres and charcoal (non - antigenic markers) was determined in seasonally acyclic maiden mares treated with either progesterone (P) n = 4, estradiol (E) n = 4 or oil vehicle (C) n = 4. At 3, 7 and 15 d after inoculation with bacteria and the 2 non - antigenic markers, uteri were flushed and the clearance of these materials, as well as the number of white blood cells and immunoglobulin concentration, determined. P-treated mares had higher numbers of bacteria and IgA and a greater volume of purulent fluid in the uterus than E- or C-treated mares at 7 d after inoculation. Clearance of inoculated materials began within 2 h in E-treated mares, and the non-antigenic markers were completely cleared in E- and C-, but not in P-treated mares, in 3 d. This suggests that in the P-dominated uterus, reduced physical clearance may contribute to an increased susceptibility to uterine infection.     

Uterine defense mechanisms in the mare: The use of intrauterine plasma in the management of endometritis

Twenty-nine mares with either active or subclinical endometritis were treated with intrauterine infusions of their own plasma in one of two treatment schemes. Twenty-six mares actively infected, with an average of 2.4 years barren, were treated with combinations of saline irrigations and plasma infusions. Twenty-four showed clinical improvement and were bred, resulting in 15 pregnancies. Three mares with subclinical endometritis were treated post-breeding with a single plasma infusion and all became pregnant. The response to plasma infusions supports in-vitro observations which implicate serum-derived opsonins, particularly complement, as enhancers of phagocytic function.     

Uterine defense mechanisms in the mare: Serum opsonins affecting phagocytosis of Streptococcus zooepidemicus by equine neutrophils

The addition of serum to uterine secretions was shown to opsonize Streptococcus zooepidemicus and significantly enhance bacterial phagocytosis by equine neutrophils. Treatment of serum by heat inactivation at 56 degrees C, EDTA treatment, and C3 consumption reduced phagocytosis and therefore demonstrated that the process was complement-dependent. The amount of C3 present in uterine secretions was measured in a series of 14 mares infected with Streptococcus zooepidemicus . Ten of the 14 mares had detectable amounts of C3; however, the C3 had been cleaved and rendered nonfunctional. The importance of these findings in relationship to chronic uterine infections in the mare is discussed.     

Immunoglobulins in uterine secretions of mares with differing resistance to endometritis

The immunoglobulins IgA, IgG, IgG(T) and IgM were measured in uterine secretions from mares with normal uterine defense capability against bacterial contamination, and in mares with lowered resistance. Samples were collected for analysis at two stages of estrus and two stages of diestrus. All mares were then challenged with a pathogenic culture of Streptococci inoculated into the uterus. The immunoglobulins were quantitated on a similar schedule post-inoculation. Generally higher amounts of IgA, IgG and IgG(T) were found in the uterine secretions of mares which had an imparied resistance to endometritis than in mares with an efficient defense mechanisms. IgM was not detected in enough samples to suggest any differences.     

Hospital work load produced by breast-cancer screening programme run by trained non-medical staff.

In a feasibility study of mass population screening for breast cancer by annual clinical examination and mammography the findings of non-medical staff (nurses and radiographers) were used to estimate the hospital work load generated by such a programme. Among 2490 women who attended for the first time by invitation the rate of referral for a surgical opinion based on the findings of the non-medical staff was 7.9% and the biopsy rate 2.5%. In the second and third years referral rates fell to 4.3% and 2.7% respectively and the biopsy rates to 1.1% and 1.4%. The rates of referral and biopsy among 1203 women who referred themselves for screening were higher, but many self-referred women were symptomatic; those without symptoms had rates of referral and biopsy similar to those of the invited women. Extrapolation of these findings to a population of 200,000 in a typical health district showed that the hospital work load would be high in the first year of screening with 44 outpatient referrals per week and 14 biopsies. By the third year, however, only seven referrals and four biopsies a week could be expected. The work load would be reduced by a third if screening were confined to women over the age of 50.     

Screening for breast cancer.

The feasibility of mass population screening for breast cancer by clinical examination and x-ray mammography was studied. The results indicate that such a programme could be conducted effectively by non-medical staff and be safe from the dangers of irradiation. The response rate of women invited for screening suggests that such a service is acceptable to the general public. The additional work load produced by screening would not overburden the existing surgical services.