A quantitative morphological study of the optic nerve of pre-weanling rats

A quantitative histological estimation of the optic nerve of pre-weanling rats has revealed that the total fiber number decreases rapidly between 7 and 25 days of age.     

A quantitative morphological study of the optic nerve of pre-weanling rats

Summary A quantitative histological estimation of the optic nerve of pre-weanling rats has revealed that the total fiber number decreases rapidly between 7 and 25 days of age.Acknowledgment. We wish to thank Professor Clegg for advice and encouragement concerning this work.     

A mechanical study of the cat retractor bulbi muscle

Zusammenfassung Die mechanischen Eigenschaften des M. retractor bulbi in der Katze (Anstiegs- und Abfallzeiten der Einzelzuckung und der tetanischen Kontraktion und Fusionsfrequenz) liegen zwischen den Eigenschaften der schnellen und langsamen Zuckungsfasern des M. obliquus inferior.

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This investigation was supported by Public Health Service Program Project Research Grant No. NB 06038, General Research Support Grant No. 5 S01 FR-05566, and Research Career Program Award No. K3-NB-14,094 to Dr.Bach-y-Rita from the National Institute of Neurological Diseases and Blindness.     

Ca-electrogenesis in mealworm muscle: A voltage clamp study

Summary The membrane current in the muscle fibre of larval mealworm,Tenebrio molitor, was characterized by an early transient inward current followed by a late outward current. The results suggest that the inward current is associated with an inward movement of Ca ions down its electrochemical gradient, and Na ions have little to contribute to the inward current in this fibre.     

A preparation for the study of muscle metabolism during rest and activity

Summary A method for the investigation of metabolism in the isolated rat extensor digitorum longus muscle has been described. This muscle was shown to be suitable for investigations of skeletal muscle metabolism during rest and activity.Recipient of a Medical Research Council Scholarship for training in research methods.     

A study of excitation-contraction coupling in frog tonic muscle fibers ofRana temporaria

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The Copernican globe: A delayed conception

The impact on globe making of the change from a Ptolemaic to a Copernican world-view is examined. As well as showing a map of the Earth and the Heavens, the main use of globes originally was to demonstrate the natural phenomena as these are observed from a geocentric perspective. In the second half of the eighteenth century some belated attempts were made to construct so-called Copernican globes for this purpose. This late response did not stop the production and use of the common Ptolemaic globe. It is argued that the technological developments of the nineteenth century made the role of the globe as a demonstration model superfluous and thus contributed more to the downfall of the common Ptolemaic globe than did any revolution in science.     

A preparation for the study of muscle metabolism during rest and activity.

A method for the investigation of metabolism in the isolated rat extensor digitorum longus muscle has been described. This muscle was shown to be suitable for investigations of skeletal muscle metabolism during rest and activity.     

A morphological study of the expression of the small G protein RhoA in resting and activated MDCK cells

The small G protein Rho subfamily controls several cellular events such as growth, movement, proliferation and differentiation by rearranging actin and cytoskeleton proteins. Most of these effects are mediated by the activation of growth factor and extracellular matrix molecule receptors, suggesting a role for Rho molecules in the transduction pathway of these receptors. Despite the importance of Rho peptides in fundamental cellular events, data on their subcellular immunolocalisation are sparse: here we investigated the expression and subcellular localisation of RhoA in resting (cultured on plastic) and activated (Matri-cell or hepatocyte growth factor) MDCK cells by immunoperoxidase and immunogold techniques. Resting MDCK cells contain detectable amounts of RhoA mainly localised in the cytoplasm; RhoA expression is significantly enhanced by Matri-cell substrates that promote translocation of RhoA at the membrane level. This enhancing effect is reduced after exposure to hepatocyte growth factor.     

Effect of nerve stimulation on rat skeletal muscle. A study of plasma membrane

The gastrocnemius muscle of the rat showed no morphological, histometric or plasma membrane changes, after sciatic nerve stimulation with a 5mA current for 30 to 60 min, 10 mA for 30 min and 15 mA for 5 min. However, 10 mA for 60 and 200 min gave rise to mitochondrial and plasma membrane abnormalities. These changes were absent after a rest period. The results indicated that the sciatic nerve stimulation at 10 mA for 60 and 200 min caused reversible changes in the rat skeletal muscle mitochondria and plasma membrane.     

Effect of nerve stimulation on rat skeletal muscle. A study of plasma membrane

Summary The gastrocnemius muscle of the rat showed no morphological, histometric or plasma membrane changes, after sciatic nerve stimulation with a 5 mA current for 30 to 60 min, 10 mA for 30 min and 15 mA for 5 min. However, 10 mA for 60 and 200 min gave rise to mitochondrial and plasma membrane abnormalities. These changes were absent after a rest period. The results indicated the sciatic nerve stimulation at 10 mA for 60 and 200 min caused reversible changes in the rat skeletal muscle mitochondria and plasma membrane.     

A comparative study of the intracellular Ca++ movements in white and red muscle

Riassunto Dopo iniezione di⁴⁵Ca⁺⁺ in conigli, radioattività appare nei mitocondri e nel reticolo sarcoplasmico del massetere dell'adduttore magno. La quantità di radioattività, e l'attività specifica del Ca⁺⁺, sono molto più elevate nei mitocondri che nel reticolo sarcoplasmico del massetere. Sono dello stesso ordine di grandezza nei due organelli dell'adduttore magno. I risultati suggeriscono un ruolo prominente dei mitocondri nei movimenti intracellulari del Ca⁺⁺ nel muscolo rosso, ed un analogo prominente ruolo del reticolo sarcoplasmico nel muscolo bianco.     

Biochemical and morphological changes induced by Triton-X 100 in skeletal muscle of rats after abdominal aorta ligation

Riassunto Il Triton-X 100 somministrato in vivo a ratti dopo legatura dell'aorta addominale provoca l'aumento di alcuni enzimi lisosomiali e la comparsa di focolai necrotici nei muscoli degli arti posteriori, simili a quelli osservabili nelle lesioni di tipo ischemico.

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This study was supported by grant (contract No. 71. 00822.04. 115.658) of the Consiglio Nazionale delle Ricerche.

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We are indebted to Mr.R. Bergo for his skilful technical assistance