Influence of temperature on blood coagulation in vitro (author's transl)]

The influence of different temperatures between 13 degrees C and 45 degrees C on coagulation factors in vitro was studied by measuring clotting time with the recalcification time, partial thromboplastin time (PTT), and thromboplastin time test. In all three tests the shortest clotting times were measured at a temperature of 40 degrees C. The relation between temperature and clotting time was similar in fresh plasma and in plasma which had been stored at a temperature of --20 degrees C before examination. However, in all tests stored plasma showed shorter coagulation times. Prolongation of coagulation time at 45 degrees C is caused by irreversible reduction of coagulation activity in the plasma. At the same time thromboplastin- and PTT-reagent are imparied in their coagulation acitvity by a temperature of 45 decrees C. In comparison to plasma obtained from healthy persons plasma from patients with hemophilia A or B or with v. Willebrand's disease reacted more sensitive to changes in temperature in the PTT test. The coagulation defect was definitely more pronounced at 27 degrees and 17 degrees C than at 37 degrees C. It was not possible to differentiate these three coagulopathies with the PTT test at 27 degrees and 17 degrees C.     

Hypohydration effect on finger skin temperature and blood flow during cold-water finger immersion.

This study was conducted to determine whether hypohydration (Hy) alters blood flow, skin temperature, or cold-induced vasodilation (CIVD) during peripheral cooling. Fourteen subjects sat in a thermoneutral environment (27 degrees C) during 15-min warm-water (42 degrees C) and 30-min cold-water (4 degrees C) finger immersion (FI) while euhydrated (Eu) and, again, during Hy. Hy (-4% body weight) was induced before FI by exercise-heat exposure (38 degrees C, 30% relative humidity) with no fluid replacement, whereas during Eu, fluid intake maintained body weight. Finger pad blood flow [as measured by laser-Doppler flux (LDF)] and nail bed (T(nb)), pad (T(pad)), and core (T(c)) temperatures were measured. LDF decreased similarly during Eu and Hy (32 +/- 10 and 33 +/- 13% of peak during warm-water immersion). Mean T(nb) and T(pad) were similar between Eu (7.1 +/- 1.0 and 11.5 +/- 1.6 degrees C) and Hy (7.4 +/- 1.3 and 12.6 +/- 2.1 degrees C). CIVD parameters (e.g., nadir, onset time, apex) were similar between trials, except T(pad) nadir was higher during Hy (10.4 +/- 3.8 degrees C) than during Eu (7.9 +/- 1.6 degrees C), which was attributed to higher T(c) in six subjects during Hy (37.5 +/- 0.2 degrees C), compared with during Eu (37.1 +/- 0.1 degrees C). The results of this study provide no evidence that Hy alters finger blood flow, skin temperature, or CIVD during peripheral cooling.     

Clinical blood chemistry values in normal Wistar-Imamichi rats using the RaBA-System (author's transl)]

In order to establish the normal baseline of blood values in rats using the RaBA-System, the following eight parameters were analyzed in 8-22-week-old Wistar-Imamichi rats of both sexes: hemoglobin, total protein, glucose, BUN, total cholesterol, GOT, GPT, and alkaline phosphatase. With the exception of glucose, all these parameters were significantly different depending upon ages. Significant sex differences were observed in the values of hemoglobin, total cholesterol, GOT, and alkaline phosphatase.     

Concanavalin A induced changes of lymphocyte p-nitrophenylphosphatase (author's transl)]

The effect of K+, Na+, Mg2+ and ATP on the p-nitrophenylphosphatase activity was investigated. As an enzyme preparation a microsomal fraction of sheep lymphocytes was used. Low concentrations of Mg2+, K+ and Na+ increased, whereas high concentrations decreased the enzyme activity. There was an inhibition of activity by ATP without Na+ in the incubation medium and an increase of enzyme activity at low K:Na-ratio. By concanavalin A in a concentration of 15 mug/ml the p-nitrophenylphosphatase activity was increased in intact cells and the microsomal fraction for 30-40%. The activation was not Na+, K+, Mg2+, p-nitrophenylphosphate or ATP dependent.     

Pattern stimulation and action potential of frog skin (author's transl)]

Experiments were carried out to investigate the relationship between the pattern of stimulus of efferent or afferent nerve and the size of action potential of frog's skin. Two kinds of preparations were used: the excised nerve skin preparation and the spinal preparation. In the range of moderate intervals of stimuli, the size of skin action potential of the nerve-skin preparation became larger with the increase of number of stimuli, (i) during a definite period of stimulation with various frequencies, or (ii) during various long periods of stimulation with constant frequency. The size of potential depended not only on number of stimuli but also on their interval. The latter property may be called pattern-sensitive. In some state of preparation the size of potential evoked by a constant number of stimuli was nearly constant, being independent from stimulus frequencies, that is, pattern insensitive. Both kinds of results were obtained in cases of the spinal preparation. Michaelis-Menten's equation could be applied to describe the relation between the size of potential and the number of stimuli. However, there was no reason to interprete this relation with a simple concentration-effect relationship. Another hypothesis was then testoned on the supposition that the response is composed of sequentially superposed unitary processes each of which was promptly evoked by each stimulus and decayed exponentially. The calculated response curve reasonably fit with the observed data. Slower processes commonly called accomodation were excluded from the present discussion and only the effect of relatively short period of stimulation was examined.