Distribution of recurrent inhibition in the human upper limb

The distribution of homonymous and heteronymous recurrent inhibition among the motor nuclei innervating the main muscles of the human upper limb has been investigated in 25 healthy subjects. Homonymous recurrent inhibition was studied with a specially designed electrophysiological method with paired H-reflexes, previously described by Bussel & Pierrot-Deseilligny (1977), combined with a pharmacological study using a cholinergic agonist, the l -acetylcarnitine (Rossi & Mazzocchio 1991). These methods were used to investigate the Flexor Carpi Radialis (FCR), Extensor Carpi Radialis (ECR), Opponens Pollicis (OP) and Abductor Digiti Minimi (ADM) motor nuclei. In the Deltoid, Triceps, Flexor Carpi Ulnaris (FCU) and Extensor Carpi Ulnaris (ECU) motor nuclei in which it was impossible to evoke clearly distinguishable H-reflexes, homonymous recurrent inhibition was studied with the PSTH technique: homonymous recurrent inhibition was found in Deltoid, Triceps, FCR, FCU, ECR, ECU motor nuclei but not in OP and ADM motor nuclei. Heteronymous recurrent inhibition was studied with the PSTH technique in the Deltoid, Biceps, Triceps, FCR, ECR, FCU, ECU, Flexor Digitorum Communis (FDC), Extensor Digitorum Communis (EDC) motor nuclei as well as those innervating the intrinsic muscles of the hand. The following results were obtained: (1) motor neurones innervating muscles acting at digits do not receive any heteronymous recurrent inhibition; (2) motor neurones innervating muscles acting at the wrist give recurrent inhibition to motor nuclei of proximal muscles but do not receive any recurrent projections from the latter; and (3) motor neurones innervating proximal muscles (acting at shoulder or elbow) are interconnected by recurrent inhibition and receive heteronymous recurrent projections from some wrist muscles but not from intrinsic hand muscles.     

Fentanyl and propofol uptake by the lung: effect of time between injections

The effect of time between the administrations of fentanyl and propofol on the first pass uptake of propofol in the cat lung was studied using double indicator dilution technique. The pulmonary first pass uptake of propofol (mean s.e.mean) was 58 6% in six cats (control group) that had received no fentanyl prior to propofol (1 mg/kg) administration. The uptake was significantly reduced to 32 3% in animals pretreated with fentanyl (1 μg/kg) 30 seconds before propofol administration (n = 6). However, when fentanyl was administered 3 minutes (n = 6) or 10 minutes (n = 6) prior to propofol, the pulmonary uptake of propofol (45 5%, 507% respectively) was not significantly reduced. The results demonstrate that the ability of fentanyl to inhibit pulmonary removal of propofol depends on its time of administration prior to propofol. These data may have clinical implication with respect to timing of the preinduction opiate injection.     

The effect of topical nitroglycerin on transcutaneous oxygen

The use of topical nitroglycerin has been reported to aid the healing of chronic skin ulcers. In this study, the effect of 2% nitroglycerin ointment on transcutaneous oxygen pressure (TcPO2) was investigated in skin adjacent to the area of ointment application. Topical nitroglycerin caused a two-fivefold decrease in TcPO2 in skin next to or up to 9 cm away from the site of application of the ointment.     

Immune Responses during Human Schistosomiasis Mansoni

Splenocytes from 25 patients with severe hepatosplenic schistosomiasis mansoni were obtained after therapeutic splenectomy. Spleen cells were phenotyped and analysed for responsiveness to mitogens or heterogeneous schistosome-derived antigenic preparations (eggs, SEA; adult worms, SWAP; cercariae, CERC) in blastogenesis assays and lymphokine production systems, and were compared with peripheral blood mononuclear cells (PBMN). Splenic lymphocytes were 55% T lymphocytes (sheep erythrocyte rosette-positive) and 37% surface immunoglobulin-positive B lymphocytes. The mean T4+:T8+ ratio of these splenocytes was 1.0. Phytohaemagglutinin stimulated spleen cell production of the lymphokine mitogenic factor, but exposure to SEA or SWAP did not. Spleen cell and PBMN blastogenic responses to SEA and SWAP were sometimes, but not always in accord. Removal of plastic adherent cells allowed the non-adherent spleen cells of 30-40% of the patients to respond substantially more vigorously to SEA, SWAP and CERC. Spleen cells from a subgroup of 20-30% of the patients failed to respond to the schistosomal antigens regardless of removal of adherent cells. Spleen cell responses to gram-negative lipopolysaccharide peaked on day 5 or 6 of culture, and were augmented by adherent cell removal. Pokeweek mitogen-stimulated responses were optimal on day 5 of culture. Spleen cells from most severe, hepatosplenic schistosomiasis mansoni patients do not respond well to schistosomal antigens or B-cell mitogens. The splenic responses of many of these patients were elevated by the removal of adherent spleen cells.     

SOME EFFECTS OF THE STEROIDAL MUSCLE RELAXANT, DACURONIUM BROMIDE, IN ANAESTHETIZED PATIENTS

The neuromuscular blocking properties of a new steroidal drug,dacuronium bromide, were investigated in twenty-three anaesthetizedpatients. Dacuronium produced a competitive type of neuromuscularblock with a potency of approximately one-tenth that of tubocurarineand one-fiftieth that of pancuronium. When compared with thesedrugs its maximal action was apparent earlier and the recoveryfrom its effects was somewhat quicker. One patient showed thesyndrome of the return of block after apparent adequate antagonismby neostigmine. Its actions in anaesthetized patients are discussedand compared with its actions in animals.