The postnatal evolution of muscular twitches in the developing rat

Summary The reported study concerns the evolution of muscular twitches during the 21 postnatal days of the normal rat pups. The data indicate an age-dependent progression of these twitches in different body regions.Acknowledgment. We thank Dr K. Chaudhary for the revision of the english text and Mrs D. Huot-Blais for her secretarial assistance.     

The postnatal evolution of muscular twitches in the developing rat.

The reported study concerns the evolution of muscular twitches during the 21 postnatal days of the normal rat pups. The data indicate an age-dependent progression of these twitches in different body regions.     

Adrenal corticosteroidogenesis after removal of ventral prostate gland

Summary Removal of the ventral prostate gland in adult male rats causes an increase in adrenal weight, and stimulation of adrenal ⁵-3-hydroxysteroid dehydrogenase activity along with elevation of serum levels of corticosterone and prolactin.     

Induction of neovascularization in vivo by glycerol

Glycerol, injected into a site between the femoral vessels of the rat, induced neovascularization, both from the preexisting microcirculation and from the side of the femoral vein facing the artery-vein interstitium where the glycerol was administered. The use of glycerol together with a known angiogenic substance (PGE₂) did not modify the neocapillary density (NCD) obtained with glycerol alone. In contrast, the lower level of NCD achieved with an acylglycerol (triacetylglycerol) was increased when the latter was associated with PGE₂. Values reached were similar to, but never higher than, those for glycerol alone, or combined with PGE₂. The results suggest that glycerol and some substances containing glycerol, amongst which 1-butyrylglycerol has been previously considered¹, may stimulate angiogenesis by a direct or indirect mechanism of action.     

Human sex-linked muscular dystrophy: Kinetics of the isometric twitch

Résumé Les propriétés mécaniques du muscle adducteur du pouce atteint de dystrophie musculaire de type Duchenne ont été étudiées in situ chez 15 malades. La force produite par la secousse isométrique et le tétanos isométrique est réduite dans tous les cas. Le temps de contraction de la secousse isométrique et son temps de relaxation sont légèrement supérieurs aux valeurs de contrôle. Cette différence disparait au cours de la stimulation répétée du nerf à 2/sec. Ces observations montrent que l'activité ATPase de la myosine (déterminant la vitesse de contraction) et le processus de séquestration du Ca⁺⁺ myoplasmique dans le réticulum sarcoplasmique (déterminant la vitesse de relaxation) ne sont pas altérés de façon irréversible dans la dystrophie musculaire de Duchenne.

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On leave from the Neurology Clinic of the Medical Academy, Warsaw.

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This work was supported by the Muscular Dystrophy Associations of America Inc. and by the Fonds de la Recherche Scientifique Médicale.     

Recovery of renal lactate dehydrogenase (LDH) isoenzyme pattern after obstruction relief in experimental hydronephrosis

Summary The release of ureteral occlusion leads to a progressive recovery in LDH isoenzyme pattern with gradual increase of anodic fractions and decrease of middle and cathodic ones. Our findings demonstrate that the recovery is accomplished on the 10–14th day, in agreement with morphological and metabolic observation.This work was partially supported by research grant C.N.R. 730056004.     

Recovery of renal lactate dehydrogenase (LDH) isoenzyme pattern after obstruction relief in experimental hydronephrosis.

The release of ureteral occlusion leads to a progressive recovery in LDH isoenzyme pattern with gradual increase of anodic fractions and decrease of middle and cathodic ones. Our findings demonstrate that the recovery is accomplished on the 10-14th day, in agreement with morphological and metabolic observation.     

Regeneration of the testes in the clawed toad (Discoglossus pictus Otth.) after complete surgical removal

Riassunto Dopo ablazione totale dei testicoli inDiscoglossus pictus si ha rigenerazione. Nei testicoli rigenerati si riscontrano spermatociti in tutti gli stadi di sviluppo e talvolta anche spermi. È avanzata l'ipotesi che la rigenerazione avvenga a partire da cellule somatiche degli spermidutti.

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With a contribution from the C.N.R.     

Sarcomere shortening and tension development during ‘isometric’ tetanus of muscle

Summary Laser diffraction and tension measurements from frog muscle during isometric tetanus reveal that the sarcomeres contract more rapidly than tension develops.Supported by the Australian Research Grants Committee and the National Health and Medical Research Council.     

Comparison of DMSO and glycerol as cryoprotectants for ascites tumor cells

Summary Mouse Ehrlich ascites and rat D23 ascites tumors were stored in liquid nitrogen under identical conditions for up to 3 years. Cell viability (trypan blue exclusion) and transplantability of both tumors in animals remained virtually unaffected if preserved in 10% DMSO containing medium, whereas, cells preserved in 10% glycerol failed to produce lethal tumors in rodents.This work was performed at the Cancer Research Unit, Royal Victoria Infirmary, Newcastle Upon Tyne, England. I thank John Geggie for expert technical assistance; to the North of England Council of the Cancer Research Campaign and the National Science Foundation (ENG-78-25432) for financial support; and to Dr John A. Dickson for advice and encouragement. Also, I am indebted to Professor Rakesh K. Jain for his support.     

Development of the maximum isometric force at short sarcomere lengths in calcium-activated muscle myofibrils

Summary Studies on the sarcomere length-force relation in Ca⁺⁺-activated vertebrate muscle myofibrils indicate that the maximum isometric force can be generated even at sarcomere lengths around 1 m, indicating that the ascending limb of the sarcomere length-force relation is virtually absent.We thank Miss S. Gomi for her technical assistance. This work was supported by the grant (No. 587028) form the Ministry of Education, Science and Culture of Japan.     

The effect of limb ischaemia on the serum glycerol concentration of the rat

Résumé Le sérum des rats présente une concentration élevée de glycérine après l'application de garrots aux membres postérieurs pendant quatre heures. L'auteur compare ses résultats avec ceux des recherches dans lesquelles les acides gras non-estérifiés ont été soumis à des mesures quantitatives.     

The occurrence of Δ3-trans-hexadecenoic acid in phosphatidyl glycerol from spinach leaves

Zusammenfassung Der Gehalt an ³-trans-Hexadecensäure im Phosphatidylglycerol aus grünen Spinatblättern (Spinacea oleracea) erweist sich als auffallend hoch. Die enzymatische Hydrolyse zeigt die C₁₆-Monoensäure mit der-Stelle des Phosphatids verknüpft.     

Permeability of fresh and stored human erythrocytes to glycerol and its acylated derivatives

Summary The effect of copper ions on the permeation of glycerol and its mono-, di-, and triacetate derivatives was studied in fresh and stored erythrocytes. Permeability was unchanged with storage. Acylated glycerols permeate the cells mainly by non-facilitated mechanism, as their transport is almost unaffected by copper ions.Portions of this work were included in the graduate thesis of Dr. Yaeger in partial fulfillment of the requirements for the M. D. degree.Acknowledgement. We thank Mrs Dalia Mazor for expert technical assistance.