Problems of conductor demonstration in haemophilia A: error possibilities in the determination of factor-VIII-associated antigen]

Difficulties in the detection of haemophilia A carriers by the determination of the ratio factor VII coagulation activity to factor VII antigen concentration are shown in part one of our investigations. The second part evaluates methodical parameters of the quantitative immunoelectrophoretic technique. According to our results reliable data can only be obtained under the following conditions: 1. At least three determinations of each sample are required and the mean value should be used as the final result. 2. Each gel plate should be calibrated separately 3. The calibration line should include values less than 100%. Factor VIII concentrates are not suitable for determination of the calibration curve, as higer dilution results in lower calculated concentration of the undiluted concentrate. Storage of pooled normal plasma at--25 degrees C is possible without significant loss of antigen concentration over 5 months. However, plasma samples of a single person show an unpredictable variation in the antigen concentration during storage over the same time.     

On the Bateleur, especially at the Nest

An account is given of one hundred hours of observations at a Bateleur'a nest in north-eastern Tanganyike Territory. The adults were a white-backed bird and a chestnut-backed, with a sub-adult; probably over three years old, in association with them. The youngster took 130 dap to fledge. During at least part of the time all its food was brought by the white-backed adult. When the fledgling was about one month old its feeds averaged about one in eight hours; during its last week in the nest feeds were nearly three times as frequent.
Literature and unpublished data are reviewed in relation to special points of interest, viz.:—
Slow development and maturation accords with longevity. Fledging period apparently longer than authentically recorded for any land bird. First wing-moult may have started before first flight.
Tail length is greater in proportion to wing in juveniles than in adults.
Proportion of white-becks to chestnut-backs differs in parts of Africa, being least in South africa. White-tailed birds seem confined to Sudanese semi-desert belt.
Voice, flight habits and wing-noises seem to differ in parts of Africa.
Food comprises both carrion and live prey, especially snakes, but not poultry or other birds. Claws are not less sharp than those of Stephanoaëtus and Polemaëtus .
Breeding records in Tropical Africa show, when analysed with reference to egg-dates, that as a rule in each area the young get through their fledging period, or at least the later, unbrooded part, during the local cool dry season.
Psychologically the Bateleur is most peculiar: in the wild it is shy of man, sociable with big birdv of its own and other species, and breeding birds tolerate sub-adults: in captivity it becomes unusually tame, has a grecting ceremony for friends and likes to be handled.     

Exploring the evolution of environmental sex determination, especially in reptiles

Environmental sex determination has been documented in a variety of organisms for many decades and the adaptive significance of this unusual sex-determining mechanism has been clarified empirically in most cases. In contrast, temperature-dependent sex determination (TSD) in amniote vertebrates, first noted 40 years ago in a lizard, has defied a general satisfactory evolutionary explanation despite considerable research effort. After briefly reviewing relevant theory and prior empirical work, we draw attention to recent comparative analyses that illuminate the evolutionary history of TSD in amniote vertebrates and point to clear avenues for future research on this challenging topic. To that end, we then highlight the latest empirical findings in lizards and turtles, as well as promising experimental results from a model organism, that portend an exciting future of progress in finally elucidating the evolutionary cause(s) and significance of TSD.     

Simultaneous determination of zymogen activation time and zymogen level using chromogenic substrates in blood coagulation analysis

The amidolytic activities of plasma generated by means of thromboplastin and Ca++, on the one hand, and by means of partial thromboplastin, a contact activator and Ca++, on the other hand, were determined using synthetic, chromogenic factor Xa substrates with low affinity for thrombin (CH3SO2-D-Leu-Gly-Arg-pNA and CH3SO2-D-Nleu-Gly-Arg-pNA). In this way, the activation process by splitting off the p-nitroaniline was followed. Besides the summary detection of factor Xa was obtained after addition of hirudin. During preincubation with partial thromboplastin and contact acti (Actin) in Ca++-free medium, an amidolytic activity so far unidentified was generated that renders evaluation of the activation process difficult. In the test system with partial thromboplastin, factor Xa could not be determined and the thrombin-like activity that can be inhibited by hirudin did not correspond to the amount of prothrombin present in plasma. In contrast, activation of factor X and prothrombin by thromboplastin and Ca++ could be followed and the content of the two zymogenes could be detected simultaneously. In general, under optimized reaction conditions, automated systems might be developed that would provide additional diagnostic information about determination of clotting time, on the one hand, and about quantitative determination of zymogen, on the other hand.     

A new decalcifying technique for immunohistochemical studies of calcified tissue, especially applicable to cell surface marker demonstration

We have developed a new decalcifying technique for use in light and electron microscopy studies utilizing immunohistochemical staining of calcified tissues. Specimens containing calcified tissues can be adequately decalcified at a pH of 7.1-7.4 and temperature of -5 degrees C, without freezing, by use of a solution containing EDTA, sodium hydroxide, and glycerol. In this study, Leu-2a, Leu-3a, Leu-4, Leu-7, Leu-12, Leu-14, Leu-M1, Leu-M2, Leu-M3, and HLA-DR-positive cells in destructive lesions of bone tissues from patients with rheumatoid arthritis and osteomyelitis were successfully detected immunohistochemically. Furthermore, the presence of HLA-DR antigen on the surface of the infiltrating cells in the same lesions could be demonstrated using the immunoelectron microscopic technique. The results reported here have not previously been obtainable using conventional decalcifying techniques.