Human plasma dopamine-β-hydroxylase: Oxygen and thermal stability

Summary There are wide individual variations in the thermal stability of human plasma dopamine--hydroxylase (DBH). Thermal stability variations have proven of value in biochemical genetic studies of many enzymes. The development of DBH thermolability depends on the exposure of plasma to oxygen. This observation may help to elucidate the biochemical basis of the genetic regulation of DBH.This work was supported in part by NIH grants HL 17487 and NS 11014.     

Purification of mouse liver thymidylate synthetase by affinity chromatography using 10-methyl-5,8-dideazafolate as the affinant

Summary Thymidylate synthetase (methylenetetrahydrofolate: 2-deoxyuridine-5-monophosphate C-methyltransferase; EC 2.1.1.45) from neonatal mouse liver has been purified 714-fold by affinity chromatography on aminohexylsepharose bound 10-methyl-5,8-dideazafolate.Supported by grant CA22754, awarded by the National Cancer Institute, DHEW.     

Complete replacement of serum in primary cultures of chick embryo brain cells by growth-promoting alpha-globulin

Summary Growth-promoting alpha-globulin (GPAG), a specific serum protein complex which induces mitotic activity in continually replicating metazoan cells in vitro, was shown in this study to support growth of astrocytes and mesenchymal cells as well as process formation of nerve cells isolated from cerebral hemispheres of chick embryos.     

Conduction velocity of peristaltic waves in the in vivo ureter: application of a new diameter gauge

Summary The conduction velocity of peristaltic movements of the canine ureter was measured under anaesthesia with a new type of diameter gauge using an image sensor. The peristaltic velocity was 34.1±6.2 mm/sec in 10 experiments. Noradrenaline at a low dosage of 1 g/kg i.v. reduced the resting diameter, increased the conduction velocity to 47–56 mm/sec, and approximately doubled the frequency of contraction. The application of acetylcholine also caused an increase in both frequency and conduction velocity (42–46 mm/sec). A plot of the conduction velocity against the mean period of peristaltic contraction was hyperbolic in shape.     

Spontaneously (genetic) hypertensive rats: Naloxone-reversible and propranolol-reversible decrease in pain sensitivity

Summary Adult spontaneously hypertensive rats (SHR) are less sensitive to painful stimuli than their normotensive controls, Wistar-Kyoto (WKY) rats. This difference can be eliminated by the specific opiate antagonist, naloxone, and by the -adrenergic blocking agent, propranol.Acknowledgment. The author wishes to thank Miss R. L. Holcomb for her editorial assistance.     

Spontaneous maze ambulation in two mouse strains

Summary A simple device is described, which permits us to quantify several parameters of spontaneous behaviour of small animals. Using this device with mice we obtained statistically satisfactory results, showing a strong genetic influence on the behavioural characteristics tested.We wish to thank Mr R. Laplace for technical help, Mr J. P. Arnould for electronic work as well as I.N.S.E.R.M.-SCR 3.     

Inhibitory tripeptide,Lys-Phe-Tyr,as a fragment of physalaemin

Summary Several peptides were separated from-chymotrypsin-treated physalaemin by high voltage paper electrophoresis, and inhibition of the excitability of a molluscan giant neurone (tonically autoactive neurone) by the tripeptide, Lys-Phe-Tyr, was demonstrated.We thank Dr Sadaaki Iwanaga of Osaka University and Dr Atsuo Inoue of Daiichi Pharmaceutical CO for their helpful advice and the donation of the tripeptide (Lys-Phe-Tyr).     

In vivo effects of Escherichia coli endotoxin on sulfobromophthalein clearance in the guinea-pig.

In vivo studies indicated that the primary effects of E. coli endotoxin on hepatic clearance of sulfobromophthalein were at the excretory level. Newborns were more sensitive to the LPS than older animals.