A comparison of the tick resistance of indigenous Mashona and crossbred Afrikander x Sussex oxen following natural tick infestation indicated that significantly more African blue ticks Boophilus decoloratus were found on the crossbred than the indigenous cattle (P < 0.05). The two groups of cattle were exposed to Babesia bigemina and Theileria taurotragi as indicated by high antibody titres on the indirect fluorescent antibody test, but no antibodies could be demonstrated to Anaplasma marginale and T. parva bovis despite the presence of their vectors. Rhipicephalus appendiculatus, Hyalomma truncatum and H. marginatum rufipes showed a seasonal distribution. The implications of the findings in terms of strategic tick control are discussed.

A 75-year-old woman with severe aortic stenosis underwent transcatheter aortic valve replacement using a 23-mm self-expanding Portico valve (Abbott). After complete deployment, it was found to be unacceptably low, with significant paravalvular regurgitation. The valve was pulled upward to the correct position successfully by using the snare maneuver. ( Level of Difficulty: Advanced. )

Concentrations of cytosolic androgen receptor, DNA and soluble protein, contents of DHT, and in-vivo uptake of 3H-DHT were measured in rat ventral prostates at 5-day intervals during sexual development. Regarding prostate weight two phases of growth were noted being separated by a period of stagnation from Day 40 to 45. Cytosolic androgen receptor, particle-bound DHT, and uptake of 3H-DHT into the 100,000-g sediment showed a clear pattern: a maximum in the prepubertal animal at age Day 20, a minimum at age Day 30 (4 days after the early pubertal rise of LH, testosterone, and DHT) followed by a second maximum on Day 55 (2 days before the beginning of fertility), and a second minimum in the young mature animal on Day 70. An intermediate peak seen at age Day 37 was not significant. Neither the time-dependent profile of the cytosolic androgen receptor nor the contents and in vivo uptake of DHT were correlated to concentrations of circulating gonadotrophins, growth hormone, and sex-steroids measured during puberty in the same strain of animals. Therefore, the regulating mechanism remains unclear.

Prostatic concentrations of androgens and androgen-receptors in developing rats .Testosterone (T), 5a-dihydrotestosterone (DHT), 3a,5 a-androstanediol, and DHT-receptors (DHT-R) were measured systematically in the prostatic c ytosol of developing rats from age day 20 (immature) through age day 56 (spermatogenesis complete). The profiles obtained at var ious maturational stages demonstrate that the prostatic contents of androgens and DHT-receptors are high in the immature animals (T 0.203 ng/mg DNA, DHT-R 1.700 fmol/ mg prostate), fall drastically just before the onset of puberty (T 0 .058, DHT-R 0.533), then peak sharply at age day 35 (T 0.739, DHT-R 1.830), a nd slowly tail off with increasing age (day 45: T 0.232, DHT-R 0.733) and by age day 56 although T remains low (0.116) DHT-R has a second peak (1 .28). The prof iles of the prostatic contents of androgens and androgen-receptors demonstrate a divergence from the pattern of circulating T ,DHT and LH during sexual ma t u r a tio n , but somehow parallels the pattern of circulating FSH till day 50. It is possible that FSH plays an important role in the regulation of intraprostatic androgens and androgen-receptors during sexual maturation.

No abstract