Isolation of an actin polymerization stimulator from bovine thyroid plasma membranes

An actin polymerization stimulator was purified from bovine thyroid plasma membranes by DNase I affinity column chromatography. Although the molecular weight of the protein was about 42,000 (42K) by sodium dodecyl sulfate polyacrylamide gel electrophoresis, it did not comigrate with actin. In the presence of 30 mM KCl, the 42K protein facilitated formation of actin filaments when analyzed by a centrifugation method, accelerated the initial phase of actin polymerization as measured in an Ostwald viscometer and increased the length of filaments as shown by electron microscopy. The 42K protein also accelerated the initial phase of actin polymerization in the presence of 100 mM KCl and 2 mM MgCl₂ but did not affect the final viscosity. The effect of the 42K protein was diminished by 5 uM cytochalasin B or 1 uM cytochalasin D. This 42K protein may anchor actin filaments onto the thyroid plasma membrane.     

Relationship between plasma volume reduction and plasma electrolyte changes after prolonged bicycle exercise, passive heating and diuretic dehydration

Plasma volume was decreased by prolonged bicycle exercise, by passive heating in warm water, by sauna dehydration, and by diuretically induced dehydration in eleven well trained subjects. Blood samples from an arm vein were taken before and after this pre-treatment, as well as after a subsequent standard exercise test (SET) on a bicycle ergometer (50%, 70% and 105% of max VO2; the SET with no pre-treatment was used as a control condition. The changes in plasma concentration of Na+, K+ and Cl- were not proportional to the calculated plasma volume changes. The Na+ and Cl- concentrations always increased in the plasma, while plasma potassium concentration was increased after prolonged exercise, but decreased after the other types of dehydrations. The standard exercise test produced a pronounced fall in total calculated plasma potassium and in K+ concentration measured 3-5 min after exercise in all types of experiments. In the standard exercise test the calculated water loss from the plasma volume was relatively large. It amounted to about 2/3 of the total water loss in the standard exercise test and was independent of the pre-treatments.     

Acridine-psoralen amines and their interaction with deoxyribonucleic acid

A series of novel compounds in which a 9-acridinyl nucleus is linked to a psoralen nucleus in the 5- or 8-position via polyamines was prepared and examined. Their reversible binding to DNA and their irreversible binding to DNA and DNA cross-linking upon irradiation with UV-A light were examined. It was found that they were all less efficiently photoreactive than 8-methoxypsoralen (8-MOP), both in cross-linking and photobinding to DNA, whereas the ratio between their photobinding and cross-linking was 40-400 times that of 8-MOP. Compounds in which the linker was attached to the 5-position in psoralen showed smaller cross-linking and photobinding efficiencies and larger ratios between photobinding and cross-linking than those of psoralens attached in the 8-position. This strongly indicates that the 9-substituents of the acridines are oriented toward the minor groove. Flow linear dichroism studies showed that the compounds were DNA intercalating with the acridine moiety, whereas the psoralen moiety in no case was clearly intercalating. This conclusion was further supported by viscometry which also strongly indicated monointercalation.     

Migration Inhibition Studies on Peripheral Leukocytes and Lymph Node Cells from Ruminants with Fascioliasis

Delayed type hypersensitivity against antigens of Fasciola hepatica has been repeatedly documented in infected hosts. Evidence has been presented to suggest that the delayed reactivity may develop earlier in the regional lymph nodes of the parasitized organ than in other lymph nodes of the body (Soulsby 1971).     

Chromosome Abnormalities in Patients Treated with Chlorpromazine,Perphenazine, and Lysergide

In a chromosome study on leucocyte cultures made in 13 patients treated with chlorpromazine, 15 treated with perphenazine, and nine treated with lysergide, a significantly higher frequency of gaps, breaks, and hypodiploid cells in the patients treated with perphenazine and lysergide occurred compared with the 41 controls studied. It is concluded that if some drugs can induce major chromosome abnormalities, and less toxic alternatives are available, the latter should be used in preference.