[Biological developmental parameters in newborns in Silesia born between the 30th and 42nd week of pregnancy]. / Wskazniki biologiczne rozwoju noworodków slaskich urodzonych miedzy 30 a 42 tygodniem ciazy.

On the basis of anthropometric data from 2985 newborns in Silesia, percentile grids were constructed of birth weight, height, head circumference, and chest circumference for boys, girls, and both sexes jointly. It was found that these parameters, especially in premature babies, were lower in comparison to those accepted for the whole country.

Stroke volume and cardiac output hypoxemic hypoxia produced by intravenous infusion of carbon dioxide.

Hypoxia produced by intravenous infusion of gaseous carbon dioxide was associated in conscious rabbits with decreases in cardiac output and stroke volume. At the same time the arterial blood pressure, oxygen uptake and blood pH decreased, whereas carbon dioxide pressure and lactate level in the arterial blood increased. Pulmonary ventilation increased too, due to the rise in the respiratory frequency and tidal volume. The fall in cardiac output and stroke volume explains a great fall of oxygen uptake in response to decrease of oxygen pressure in the blood.

Hypercapnia-induced thermoregulatory disturbances in rabbits at low ambient temperature.

The effect of 30 minute inhalation of a gaseous mixture containing 6% CO2, 21% O2 and 73 N2 on the thermoregulatory reactions was studied in rabbits at ambient temperatures (Ta) of 6 and 18 degrees C. At Ta 6 degrees C the CO2 inhalation caused a greater fall of the rectal temperature (Tre) as well as the subcutaneous and skin temperatures (TS1 and TS2) than at Ta 18 degrees C. At the same time, the gradients Tre-TS1 and TS1-TS2 decreased, the respiratory rate increased and the electrical activity of skeletal muscles was depressed in both thermal conditions. A considerable fall in heat production occurred only at Ta 6 degrees C, at which the initial electric activity of the skeletal muscles was also greater. These results suggest that Tre fall associated with CO2 inhalation at low temperatures was caused mainly by inhibition of shivering-thermogenesis, however, the changes in skin temperatures were without any greater importance for the body temperature at Ta 6 degrees C as well as at 18 degrees C.

A simple method for accurate temperature measurement.

A simple method, employing thermocouples, was developed for measurement of temperature with an accuracy of 0.05 degrees C. The method is based on the principle of a compensatory measurement of the thermocouple voltage, with application of an additional amplifier. The temperature level of the reference thermocouple was shifted from 0 degrees to 37 degrees C, using a compensating voltage. Within a smaller range (37 degrees -- 43 degrees C) the voltage of the measuring thermocouple was additionally amplified, which resulted in an increase in sensitivity and accuracy of the temperature measurement in animal tissues. The electronic circuit and calibration procedure are presented in detail.

Influence of hypercapnia on certain aspects of heat exchanges at room temperature in the rabbit.

Heat production as well as heat loss from the surface of the ear and airways during and after hypercapnia induced by one hour inhalation of 10% mixture was studied in conscious rabbits. The arterial CO2 tension increased by about 45 mm Hg and pH fell by about 0.3. These changes were associated with decreasing of heat production while heat loss from the ears and airways increased significantly. Consequently the rectal temperature fell meanly by about 0.9 degrees C. The data show that fall of body temperature in the rabbits exposed on 10% CO2 at room temperature is due both to heat production changes and heat loss changes.