[Possible mechanism of hyperemia in the skin caused by non-painful mechanical pressure].

It is believed that hyperemia in the skin, resulting from applied weak mechanical pressure delays the development of ischemia, and that it is a defensive neurovascular reaction against the local pressure, which can be considered as a critical point in terms of prevention of ischemia and, respectively, the risk for development of bedsores. Taking into account that nitric oxide can be released from autonomic nerves and make a significant contribution to the functioning of the mechanism of neurogenic vasodilation in different tissues, and the fact that the same role can also play the calcitonin gene-related peptide, the aim of this study was to clarify the role of each of these factors in the development of local hyperemia caused by non-painful, mechanical pressure on the skin. In experiments on white rats with a quantitative measurement of the intensity of skin blood flow, it was confirmed that in case of non-painful pressure acting on the skin, two-phase reaction of local blood flow appears - at first there is an increase in its level, and then an exponential decrease with stabilization at a level below the initial one. Analysis of received data allow to make conclusion that in relization of this phenomenon the role of trigger element belongs to nitric oxide, and the role of the executing unit - to calcitonin gene-related peptide. The effectiveness of this combined mechanism is limited by development of dominance of pressor-induced mechanical compression of cutaneous vessels over its vasodilator effect.

[Iodine deficiency in the prenatal period may form learning ability deficiency in the postnatal period].

The present study analysis the changes in learning ability of the progeny of rats suffered from iodine deficiency. Reduction of serum thyroxin in the mothers' blood during three months before mating and whole period of gestation to an average level of 4,7+/-0,6 ng/ml, significantly worsened the learning ability in progeny, and the reduction to 1,1+/-0,4 ng/ml - completely deprived progeny's learning ability. Passage of the maze for these animals was purely probabilistic in nature without any signs of learning We can conclude that the diet with very low iodine content results in a low level of thyroxin in maternal serum and neurological deficiency in progeny manifested by learning disability during maze testing. Addition of the iodine to the diet prevents development of mentioned neurological deficiency.

Changes in tumor tissue oxygenation during microwave hyperthermia: clinical relevance.

As previously described (Bicher 1981) TpO2 and blood flow increase in tumor as temperature increases until 41 degrees C and decrease thereafter (microcirculation "breaking point"). In the present clinical study using O2 microelectrodes this response was reproduced in over 54 treatment sessions. However, it was found that as treatment progresses (patients are treated for one hour 10 times, twice weekly, and concomitantly receive 4000 rads of ionizing radiation) the initial increase of blood flow and TpO2 is reduced and there is immediate decrease in tissue oxygenation. A correlation between microvascular tumor physiological changes and tumor treatment responses is being developed.