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Biomedical subjects

C Morin

Publications and source records attributed to C Morin.

At least 163 records · Page 9Linked to original sources
PubMed1978

Mechanism of monosynaptic reflex reinforcement during Jendrassik manoeuvre in man.

The facilitating effect of the Jendrassik manoeuvre on monosynaptic reflexes in man has been studied by comparing H and T reflexes of the soleus and by blocking the effects of spindle activation by ischaemia of the leg. The Jendrassik manoeuvre equally enhances H and T reflexes provided that the test reflexes are small. The H reflex remains facilitated when the spindle activation cannot affect the soleus alpha-motoneurones--that is, when the Ia afferent nerve fibres from the soleus are blocked by ischaemia. It is concluded that the facilitating effect of the Jendrassik manoeuvre on the alpha-motoneurones is not predominantly routed via the gamma-loop.

Achilles Tendon↗
PubMed1978

[Peripheral and central factors controlling reciprocal Ia inhibition in man].

Variations of the soleus H reflex were studied during voluntary contractions of the tibialis anterior in man. At the onset of contraction there was a weak inhibition of the soleus H-reflex which was not related to the force of the tibialis anterior contraction. 110 msec after the onset of the EMG activity the inhibition became secondarily more marked and was then related to the force of the contraction. This secondary potentation of the H-reflex inhibition is brought about by group I fibres activity, since it was markedly reduced during ischemia of the leg. It is concluded that the early inhibition is only due to suprasegmental activity whereas during the secondary part of the inhibition, there is a supplementary inhibitory action likely brought about by Ia fibres tibialis anterior. The secondary potentiation of the inhibition is therefore likely to be produced via the gamma loop.

Central Nervous System↗
PubMed1977

Role of Ia afferents in the soleus motoneurones. Inhibition during a tibialis anterior voluntary contraction in man.

Variations of the soleus H-reflex were studied during voluntary isometric or anisometric contractions of the tibialis anterior in man. At the onset of isometric contractions there was a weak inhibition of the soleus H-reflex, which was not related to the force of the tibialis anterior contraction. 110 msec after the onset of the EMG activity, the inhibition became secondarily more marked and was then related to the force of the contraction. This secondary potentiation of the H-reflex inhibition is brought about by group I fibres activity, since it was markedly reduced during ischemia of the leg. It persisted during local muscular fatigue, this indicating that Ib fibres from tibialis anterior are not involved and that, by the process of elimination, group Ia fibres must be responsible for the supplementary secondary inhibition. It is concluded that the early inhibition is only due to suprasegmental activity, whereas during the secondary part of the inhibition there is a supplementary inhibitory action brought about by Ia fibres from tibialis anterior. The secondary potentiation of the inhibition is therefore likely to be produced via the gamma loop.

Adult↗
PubMed1977

Influence of voluntary movement and posture on recurrent inhibition in human subjects.

Recurrent inhibition elicited by a conditioning H reflex is measured in normal man by the amount of inhibition of a test H reflex produced by motoneurones that have already given rise to the conditioning reflex. The recurrent inhibition of soleus motoneurones is lowered during a voluntary contraction of this muscle while it is enhanced during a voluntary contraction of its antagonist, the tibialis anterior, and not modified during a contraction of the quadriceps. This recurrent inhibition is also enhanced when the subject is standing without support. These changes in recurrent inhibition are thought to imply supraspinal mechanisms acting on Renshaw cells. The functional significance of these changes is discussed in relation to the recent finding in animals of recurrent depression of the transmission in the Ia inhibitory pathway.

Adult↗
PubMed1977

Conditioning of H reflex by a preceding subthreshold tendon reflex stimulus.

The soleus H reflex excitability cycle has been studied using, as conditioning stimulus, a mechanical tap, subthreshold for the tendon reflex, which was applied either on the Achilles tendon, the short biceps tendon, or the quadriceps tendon. In all cases there was an early facilitation followed by a longlasting inhibition of the test H reflex. The same results were obtained in patients with a complete spinal cord section. Wherever the site of the conditioning stimulation, these modifications disappeared after ischaemia of the leg. It is concluded that the effects observed are due to the activation by the tendon tap of the Ia nerve fibres from the soleus muscle, and that the longlasting inhibition is probably due to a transmitter depletion.

Adult↗
PubMed1976

Rectal biopsy in type 4 glycogenosis. An ultrastructural cytochemical study.

Rectal biopsy material from a patient with type 4 glycogenosis was studied by ultrastructural cytochemical methods. The diagnosis of the disease was made on the basis of the patient's clinical history, the autopsy findings, and the histopathological features. Numerous large macrophages were observed in the rectal mucosa. They contained large vacuoles filled with filamentous material and small granules. This amylopectin was stained by the Thiery method (periodic acid-thiocarbohydrazide-silver proteinate) after 18 hours of exposure to thiocarbohydrazide; only 30 minutes was sufficient to demonstrate seemingly normal beta-glycogen particles in epithelial cells.

Autopsy↗
PubMed1976

Short term hypothermic perfusion for intestinal preservation with dimethyl sulfoxide.

Morphologic changes, resulting from intracellular or extracellular perfusates with dimethyl sulfoxide as a cryophylactic agent, are similar and probably due to the anoxic period, after short term perfusion. These changes are temporary and are followed by complete recovery. No statistically significant changes in disaccharidase activity between intracellular and extracellular perfusates are found in the jejunal mucosa. No differences are found between normal disaccharidase activity and values obtained experimentally. Results of this study support the suggestion that vascular endothelial damage, as observed in evaluations utilizing the electron microscope, is certainly an important factor in the limitation of perfusion techniques of the intestine.

Animals↗
PubMed1973

Laparoscopy: the method of choice for sterilization and investigation of infertility.

The increasing demand for sterilization as a permanent and effective form of birth control leads one to consider the various methods available to achieve this end. Tubal cauterization and excision by laparoscopy appears to be a safe, efficient method.The technique used is carefully reviewed step by step. The absence of major complications in this series of 115 consecutive laparoscopies certainly supports the safety of the procedure. The low morbidity, short hospital stay and minimal time required appeal particularly to the working mother. The absence of an abdominal scar is also much appreciated. The procedure, when used for investigation of infertility, provides far more information than other current methods.

Adult↗
PubMed1972

[Not Available].

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Demography↗