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H Barbeau

Publications and source records attributed to H Barbeau.

64 records · Page 4Linked to original sources
PubMed1987

Action of 5-hydroxytryptamine, substance P, thyrotropin-releasing hormone and clonidine on motoneurone excitability.

We have investigated the influence on the excitability of lumbar motoneurons of 5-hydroxytryptamine (5-HT), substance P and thyrotropin releasing hormone (TRH), three substances which coexist in the same bulbospinal descending pathway and end in large part around motoneurons. We have also studied the effect of clonidine, an alpha 2 noradrenergic agonist. This was done in spinalized rats (T5) treated three weeks before with 5-7-dihydroxytryptamine. Under those circumstances 5-HTP (I.P.), 5-HT (intrathecally) TRH (I.P. or I.T.) and substance P (I.T.) all elicited a strong excitation of motoneurons as measured by integrated EMG of the hindlimb muscles. Substance P reduced by almost half the subsequent response to 5-HTP, 1 hour and 24 hours later. TRH given acutely did not modify the response to 5-HTP but given chronically for twenty one days by means of Alzet minipump, markedly increased the response to 5-HTP. Clonidine by itself decreased the excitability of motoneurons and antagonized the excitatory effect of 5-HTP and TRH. In a pilot trial, cyproheptadine, a 5-HT antagonist was shown to decrease the manifestations of spasticity in patients with a partial spinal lesion. Clonidine also appears to be of potential use in the treatment of spasticity.

5-Hydroxytryptophan↗
PubMed1986

Quantitative assessment of the effect of cyproheptadine on spastic paretic gait: a preliminary study.

The effects of cyproheptadine were studied in two patients with spastic paresis. The study consisted of two phases: a control phase (no medication) and a cyproheptadine phase (8 mg t.i.d.). The effects were evaluated from electromyographic (EMG) and kinematic analysis of treadmill walking with a portion of body weight supported, and from clinical examination and subjective assessments. Episodes of spontaneous spasms and elicited clonus were reduced with cyproheptadine. Improvement in locomotor function was evidenced by a decreased cycle duration, more regular foot-floor contact, functional joint excursions, and increased walking speed. In addition, a tonic EMG activity pattern was replaced by phasic muscle activation in the proximal extensors especially. Selective proximal movements were unmasked (hip flexion) and certain functional activities (transfers, dressing) were facilitated. The results support the role of cyproheptadine as an antispastic medication. Study of the short-term and long-term benefits of cyproheptadine is continuing.

Adult↗
PubMed1982

Vertically oriented alternating acetylcholinesterase rich and poor territories in laminae VI, VII, VIII of the lumbosacral cord of the rat.

The pharmaco-histochemical method for the demonstration of acetylcholinesterase has been applied to study the spinal cord of the rat. Twenty rats were treated with di-isopropylphosphofluoridate at various time intervals before death and their lumbosacral cord sectioned in either the sagittal, horizontal or transverse plane. Under such conditions, the acetylcholinesterase activity of the neuropile which normally masks many neurons is minimal. The distribution of acetylcholinesterase-containing neurons corresponds to that described previously by various authors, but now the acetylcholinesterase-containing perikarya and their processes may be visualized to a degree not previously attained. This aspect of the technique has allowed us to observe very clearly some features of the internal organization of the spinal cord at the lumbosacral level. The original finding of the present work is the disclosure of alternating bands of dark and light acetylcholinesterase activity at the level of the intermediate grey (laminae VI, VII and VIII) along the rostrocaudal extent of the lumbosacral segments of the rat spinal cord. Dendritic bundling extending over long distances has also been observed at different sites in the ventral horn and in the intermediolateral cell column.

Acetylcholinesterase↗
PubMed1982

Action of cyproheptadine in spastic paraparetic patients.

The antiserotonergic agent cyproheptadine was evaluated in six patients as a medication for the management of spasticity due either to spinal cord trauma or to multiple sclerosis. Oral doses of cyproheptadine were progressively increased from 6 mg to 24 mg per day. Trial periods extended from 4 to 24 months and included a placebo substitution period. Cyproheptadine was found to decrease significantly the spontaneous and elicited ankle clonus in all six patients and spontaneous spasms in five patients. Cyproheptadine decreased the EMG activity and the dynamic strength produced by the knee extensor and flexor muscles during isokinetic movements in two of the four patients evaluated objectively. Subjectively, however, the patients did not report diminished strength.

Adult↗
PubMed1980

A preliminary study of dynamic muscle function in hereditary ataxia.

Dynamic muscle function was evaluated in nine patients with Friedreich's ataxia (FA) and eight with autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS). The measurement of torque throughout maximum voluntary isokinetic knee movements was used to quantitatively describe muscle weakness in the ataxic patients. Both FA and ARSACS patients were shown to have decreased dynamic strength in comparison to normal values during knee extension and flexion movements at 30 degrees/s. In the FA patients a lower torque-producing capacity was seen in the older patients. The electromyographic (EMG) activity was recorded in lower extremity muscles during the movements. In the vastus lateralis (VL), deviations from the normal EMG activation pattern were described in both groups of patients. A reduced amplitude in the EMG activity in the medial hamstrings (MH) was seen in the majority of the patients. An index of coactivation was defined by comparing the EMG activity when a muscle lengthened (antagonistic) to the EMG activity when the same muscle shortened (agonistic) during the isokinetic contractions. In comparison to normal values increased coactivation indexes were present in the VL and MH in patients of both groups. The characteristics of dynamic muscle strength and the activation of agonistic and antagonistic muscles described in the present study will provide the basis of evaluation for the effects of therapy in these patients.

Adolescent↗
PubMedDate not supplied

The evolution of walking-related outcomes over the first 12 weeks of rehabilitation for incomplete traumatic spinal cord injury: the multicenter randomized Spinal Cord Injury Locomotor Trial.

BACKGROUND: The Spinal Cord Injury Locomotor Trial (SCILT) compared 12 weeks of step training with body weight support on a treadmill (BWSTT) that included overground practice to a defined but more conventional overground mobility intervention (CONT) in patients with incomplete traumatic SCI within 8 weeks of onset. No previous studies have reported walking-related outcomes during rehabilitation. METHODS: This single-blinded, randomized trial entered 107 American Spinal Injury Association (ASIA) C and D patients and 38 ASIA B patients with lesions between C5 and L3 who were unable to walk on admission for rehabilitation. The Functional Independence Measure (FIM-L) for walking, 15-m walking speed, and lower extremity motor score (LEMS) were collected every 2 weeks. RESULTS: No significant differences were found at entry and during the treatment phase (12-week mean FIM-L = 5, velocity = 0.8 m/s, LEMS = 35, distance walked in 6 min = 250 m). Combining the 2 arms, a FIM-L >or= 4 was achieved in < 10% of ASIA B patients, 92% of ASIA C patients, and all of ASIA D patients. Walking speed of >or= 0.6 m/s correlated with a LEMS near 40 or higher. CONCLUSIONS: Few ASIA B and most ASIA C and D patients achieved functional walking ability by the end of 12 weeks of BWSTT and CONT, consistent with the primary outcome data at 6 months. Walking-related measures assessed at 2-week intervals reveal that time after SCI is an important variable for entering patients into a trial with mobility outcomes. By about 6 weeks after entry, most patients who will recover have improved their FIM-L to >3 and are improving in walking speed. Future trials may reduce the number needed to treat by entering patients with FIM-L < 4 at > 8 weeks after onset if still graded ASIA B and at > 12 weeks if still ASIA C.

Adult↗