Dihydrokainic acid affects extracellular taurine and phosphoethanolamine levels in the hippocampus

The specificity of the inhibitory effect of dihydrokainic acid on the high-affinity glutamate uptake was tested in an in vivo system. The rabbit hippocampus was perfused with Krebs--Ringer bicarbonate medium to which dihydrokainic acid was added (final concentrations 1 and 5 mM) with or without depolarizing potassium concentrations. Dihydrokainate elevated the levels of glutamate, taurine and phosphoethanolamine. This response was partly similar to that observed after high potassium administration. The selectivity of dihydrokainic acid is thus not restricted to glutamate, and its value as a tool in the study of glutamatergic transmission is discussed.

Effects of in vivo administration of kainic acid on the extracellular amino acid pool in the rabbit hippocampus

The effect of local administration of kainic acid in the rabbit hippocampus was studied; the hippocampus was perfused continuously in the freely moving animal with an implanted 0.3-mm dialysis fiber. The pattern of endogenous amino acids in the perfusate, reflecting extracellular amino acids, was monitored with liquid chromatography separation and fluorimetric detection of amino acid derivatives. Kainic acid was included in the perfusion medium for up to 70 min at 0.1-1.0 mM and, with time, induced epileptiform activity. Endogenous glutamic acid, taurine, and phosphoethanolamine levels were increased selectively at the lower perfusion concentrations of kainic acid. Long perfusion periods with higher concentrations increased the levels of virtually all amino acids. Perfusion of the hippocampus with depolarizing concentrations of potassium gave an amino acid response partly similar to that seen with kainic acid treatment. However, one notable difference between the two responses was that the extracellular concentration of glutamine, although not influenced by kainic acid, was significantly decreased after high potassium concentrations. These results confirm previous notions that kainic acid has a primarily excitatory effect, one manifestation of this effect being the release of glutamic acid.

Development of susceptibility to audiogenic seizures in DBA/2J and Rb mice: toward a systematic nomenclature of audiogenic seizure levels

A systematic nomenclature of levels of audiogenic seizures has been proposed and applied to describe the developmental changes in susceptibility in Rb-1, Rb-2 and DBA/2J mice.

[Functional treatment of humerus fractures by Sarmiento's method]

We treated 14 cases of fracture of the shaft of the humerus with the functional method published by A. SARMIENTO in 1977, consisting of a plastic sleeve and early introduction of functional activity. The results were excellent, healing time and restoration of motion have been rapid.

Intrarenal distribution of oxalic acid, calcium, sodium, and potassium in man

The renal papilla in man has been shown to contain a high concentration of oxalate (5 . 5 +/- 0 . 8 mmole/kg wet weight, mean +/- SEM, n = 7 kidneys), and that there is a significant concentration gradient between oxalate in the papilla and that of the medulla (0 . 4 +/- 0 . 08, P < 0 . 05) and the cortex (0 . 3 +/- 0 . 06, P < 0 . 05). Significant calcium and sodium gradients between renal papilla and medulla and cortex were confirmed and parallel that of oxalate. Potassium showed a significant decrease in the papilla (33 . 1 +/- 0 . 9) as compared to the medulla (42 . 1 +/- 1 . 9 P < 0 . 05). The concentrations of oxalate and calcium in the papilla were respectively 25-fold and 6-fold higher than the urinary concentration of oxalate and calcium. It is concluded that these high concentrations of oxalate and calcium in the renal papilla are related to the formation of Randall's plaques and may be an essential factor in the pathogenesis of renal stones which is still far from clear.

Calcium and oxalate concentrations in human renal tissue: the key to the pathogenesis of stone formation?

On the basis of what we know about urinary supersaturation and particle growth inhibitors stone formation is unlikely to start from free crystalluric particles in the renal tubule. Therefore, the object of this study is to report data on the intrarenal distribution of calcium and oxalate in man and to examine a possible relationship between calcium and oxalate concentrations in the renal tissue and stone formation. Fresh human renal tissue was obtained at operation from 7 subjects. The calcium concentrations in the papilla, medulla and cortex were measured by atomic absorption spectrophotometry. A radioenzymatic procedure was used to determine the corresponding oxalate concentrations. Significantly higher concentrations of calcium and oxalate were observed in the papilla compared to the medulla. The medulla, in turn, contained higher concentrations than the cortex. Calcium and oxalate concentrations were 6 and 25 times higher in the normal papilla than in the urine, respectively. The ion product of calcium oxalate concentrations in the human renal tissue have not been investigated, although the frequent finding of calcification in the renal papilla suggests that they may exist. The observed intrarenal calcium and oxalate concentration gradients seem to be a significant mechanism in the pathogenesis of papillary calcification and a strong indication for renal stone formation to start from fixed crystalluric particles in the papilla.

The primary structure of histone H1 from sperm of the sea urchin Parechinus angulosus. 2. Sequence of the C-terminal CNBr peptide and the entire primary structure

The primary structure of sperm histone H1Parechinus has been determined. H1Parechinus consists of a polypeptide chain of the following 248 amino acid residues: Pro-Gly-Ser-Pro-Gln-Lys-Arg-Ala-Ala-Ser-Pro-Arg-Lys-Ser-Pro-Arg-Lys-Ser-Pro-Lys-Lys-Ser-Pro-Arg-Lys-Ala-Ser-Ala-Ser-Pro-Arg-Arg-Lys-Ala-Lys-Arg-Ala-Arg-Ala-Ser-Thr-His-Pro-Pro-Val-Leu-Glu-Met-Val-Gln-Ala-Ala-Ile-Thr-Ala-Met-Lys-Glu-Arg-Lys-Gly-Ser-Ser-Ala-Ala-Lys-Ile-Lys-Ser-Tyr-Met-Ala-Ala-Asn-Tyr-Arg-Val-Asp-Met-Asn-Val-Leu-Ala-Pro-His-Val-Arg-Arg-Ala-Leu-Arg-Asn-Gly-Val-Ala-Ser-Gly-Ala-Leu-Lys-Gln-Val-Thr-Gly-Thr-Gly-Ala-Ser-Gly-Arg-Phe-Arg-Val-Gly-Ala-Val-Ala-Lys-Pro-Lys-Lys-Ala-Lys-Lys-Thr-Ser-Ala-Ala-Ala-Lys-Ala-Lys-Lys-Ala-Lys-Ala-Ala-Ala-Ala-Lys-Lys-Ala-Arg-Arg-leads to Lys-Ala-Lys-Ala-Ala-Ala-Lys-Arg-Lys-Ala-Ala-Leu-Ala-Lys-Lys-Lys-Ala-Ala-Ala-Ala-Lys-Arg-Lys-Ala-Ala-Ala-Lys-Ala-Lys-Lys-Ala-Lys-Lys-Pro-Lys-Lys-Lys-Ala-Ala-Ala-Lys-Lys-Ala-Lys-Lys-Pro-Ala-Lys-Lys-Ser-Pro-Lys-Lys-Ala-Lys-Lys-Pro-Ala-Lys-Lys-Ser-Pro-Lys-Lys-Lys-Lys-Ala-Lys-Arg-Ser-Pro-Lys-Lys-Ala-Lys-Lys-Ala-Ala-Gly-Lys-Arg-Lys-Pro-Ala-Ala-Lys-Lys-Ala-Arg-Arg-Ser-Pro-Arg-Lys-Ala-Gly-Lys-Arg-Arg-Ser-Pro-Lys-Lys-Ala-Arg-Lys. The protein consists of three domains. Compared to other H1 and H5 histones, there is a very similar hydrophobic central domain and the carboxyl-terminal domain is very rich in lysine and alanine. H1Parechinus is similar to H5 histones in that the carboxyl-terminal domain also contains many arginine residues close to the carboxyl terminus. The carboxyl-terminal domain of H1Parechinus appears to have been constructed by a series of variable duplications. The amino-terminal domain of H1Parechinus is longer and quire different to that of other H1 and H5 histones and is characterized by a repeating tetrapeptide of the general type Ser-Pro-(basic)2. The known sequence of a histone H1 gene from Psammechinus miliaris [Schaffner, W. et al. (1978) Cell, 14, 655-671] is compared to the sequence of H1Parechinus. Again the central hydrophobic domains are similar whereas the amino terminal domains are very different. The functions of the various domains of sperm histone H1Parechinus are discussed.

[Hemostaseological problems with artificial heart-valves (author's transl)]

The risk of thrombo-embolic episodes in patients with artificial heart-valves has been reduced by means of improved material and of anticoagulation. Kinetic studies, however, indicate a correlation between the risk of thrombo-embolism and an increased platelet turnover. Therefore a therapy with platelet aggregation inhibitors has been recommended. In addition to an increased platelet turnover, other risk factors have been evaluated like the material, the number, and the position of the artificial valves, the time elapsed since surgery, cardiologic disease, and anamnestic criteria. We proposed a semiquantitative risk score taking in account all these risk factors to avoid unnecessary coagulation treatment and to recommend antiplatelet therapy, where necessary. This risk score could be a basis to evaluate controlled studies.

Acoustic signals in mouse maternal behavior: retrieving and cannibalism

The purpose of this study was to show that juvenile acoustic signals are not essential prerequisites for inhibiting parental aggression or for eliciting maternal care. This was demonstrated by comparing the behavior of Rb-3 and GFF+/+ female mice with normal audition and that of a deaf mutant GFF dn/dn. 243 females and 609 litters were used to measure cannibalism and 54 females to measure speed of retrieval. Neither rate of cannibalism nor speed of retrieval were modified by deafness, thus verifying the proposed hypothesis.