Qualitative and quantitative explanation of the forms of heat sensitive organs in snakes

Heat sensitive pit organs in different species of snakes show various shapes. The relation between form characters and functions were analysed by means of two different research programs. This paper presents the methodological steps involved in these research programs. The first approach is called a qualitative explanation because it connects experimental data by means of qualitative statements in order to give a functional morphological explanation for the construction of the pits in respect to the behaviour of the snake. The second approach is called a quantitative explanation because the core of the explanation is a mathematical model which in its consequences explaines the construction of the pits in respect to image formation.     

Ultraviolet light modification of the prostaglandin receptor

Prostaglandin E₁ elicits minimal inhibition of ultraviolet lightinduced platelet aggregation. Exposure to ultraviolet light progressively inhibits prostaglandin-induced responses in both the ADP-aggregating platelet and in uterine smooth muscle. This effect, which is cumulative and lasting, may be prevented or fully reversed by a sulfhydryl-oxidizing agent. Ultraviolet light may, therefore, initiate reduction of critical disulfide groups in the vicinity of the prostaglandin receptor. The technique of ultraviolet irradiation may serve as a useful tool in the specific determination of prostaglandins in biological systems.     

Alkaline phosphatase activity in human polymorphonuclear leukocytes

Synopsis Alkaline phosphatase has been localized ultracytochemically in PMN of man with normal and elevated levels of this enzyme. Contrary to guinea-pig PMN, no activity appears to be present in the specific granules. Instead, the plasma membrane and the membrane of the endocytic vacuoles show a strong staining. However, the demonstration of this activity depends on the preparatory procedure employed for PMN isolation. the use of dextran and Ficoll-Hypaque in the isolation procedure induces a marked increase in alkaline phosphatase staining of the PMN plasma membrane. Strongly increased activity at this site has been found in PMN from cancer patients. In most of them, additional staining has been observed in atypical vesicles and sometimes in the Golgi apparatus. These findings are discussed in the light of some previously reported controversial biochemical and cytochemical data on the distribution of alkaline phosphatase in human PMN.