Arsenic-lipid complex formatinon during the active transport of arsenate in yeast

In studying formation of an arsenic-lipid complex during the active transport of (74)As-arsenate in yeast, it was found that adaptation of yeast to arsenate resulted in cell populations which showed a deficient inflow of arsenate as compared to the nonadapted yeast. Experiments with both types of cells showed a direct correlation between the arsenate taken up and the amount of As-lipid complex formed. (74)As-arsenate was bound exclusively to the phosphoinositide fraction of the cellular lipids. When arsenate transport was inhibited by dinitrophenol and sodium azide, the formation of the As-lipid complex was also inhibited. Phosphate did not interfere with the arsenate transport at a non-inhibitory concentration of external arsenate (10(-9)m). The As-adapted cells but not the unadapted cells were able to take up phosphate when growing in the presence of 10(-2)m arsenate.     

Factors influencing the stability of acid-precipitated polyvalent Bordetella pertussis bulk suspensions.

According to the statistical analysis of the potency values of acid precipitated polyvalent bulk suspensions of Bordetella pertussis, the potency of suspensions decreased below 8 IU/30 IOU during storage for 5 to 9.8 years. The average annual decrease over a 13-year period was 2.03 IU/30 IOU. The periodicity in the decrease of potency values was assumed to be connected with changes in the quality of the casein hydrolysate ingredient of the medium. Periodic functions employed to approach potency values with limits of 1 SD falling within the range of 64--156% indicated that the potency decreased below 8 IU/30 IOU after 9 years.     

Double cortical control acting upon activities of intralaminar thalamic cells

We report the effects exerted by the cortex upon the intralaminar thalamic nucleic, as revealed by reversible blockade of the cortex with spreading depression in awake rats. Extracellular recordings of spontaneous activity were made simultaneously at thalamic and cortical sites. The effect of peripheral receptive field stimulation was to decrease activity of intralaminar thalamic cells. Cortical recordings revealed the cortical regions affected by spreading depression. Two type of cells were identified depending on the changes in their sensorial responses during the cortical spreading depression propagation. The first exhibited a tonic facilitating cortical control when the cortical spreading depression was located at A 8.0 to A 10.0. The second type exhibited a disappearance of the sensorial responses when cortical spreading depression was located at A 4.0 to A 8.0 and also displayed the tonic facilitating control. This indicates that two different identified cortical regions influenced the thalamic activity.     

Diabetes-induced rat hyposensitivity to compound 48/80

Rat mortality and contractile responses of isolated tracheas to compound 48/80 from rats made diabetic 4 days before by a single intravenous injection of alloxan and from diabetic rats that had been treated with insulin 6 h before were compared with control animals. Diabetic animals and tracheal segments from diabetic rats were significantly less responsive to compound 48/80 than control and insulin-treated diabetic animals. On the other hand, diabetic animals have a lower quantity of peritoneal mast cells than control rats, and insulin restored the normal quantity of cells in diabetic animals. These data indicate that diabetes elicits an hyposensitivity to compound 48/80, possibly related to a diabetes-induced decrease in the mast cell count.