Synergistic motor nerve fiber transfer between different nerves through the use of end-to-side coaptation.

End-to-end nerve repair is a widely used and successful experimental microsurgical technique via which a denervated nerve stump is supplied with reinnervating motor or sensory axons. On the other hand, questions are still raised as concerns the reliability and usefulness of the end-to-side coaptation technique. This study had the aim of the reinnervation of the denervated forearm flexor muscles in baboons through the use of an end-to-side coaptation technique and the synergistic action of the radial nerve. The median and ulnar nerves were transected, and the motor branch of the radial nerve supplying the extensor carpi radialis muscles (MBECR) was used as an axon donor for the denervated superficial forearm flexors. A nerve graft was connected to the axon donor nerve through end-to-side coaptation, while at the other end of the graft an end-to-end connection was established so as to reinnervate the motor branch of the forearm flexors. Electrophysiological investigations and functional tests indicated successful reinnervation of the forearm flexors and recovery of the flexor function. The axon counts in the nerve segments proximal (1038+/-172 S.E.M.) and distal (1050+/-116 S.E.M.) to the end-to-side coaptation site and in the nerve graft revealed that motor axon collaterals were given to the graft without the loss or appreciable misdirection of the axons in the MBECR nerve distal to the coaptation site. The nerve graft was found to contain varying, but satisfactory numbers of axons (269+/-59 S.E.M.) which induced morphological reinnervation of the end-plates in the flexor muscles. Accordingly, we have provided evidence that end-to-side coaptation can be a useful technique when no free donor nerve is available. This technique is able to induce limited, but still useful reinnervation for the flexor muscles, thereby producing a synergistic action of the flexor and extensor muscles which allows the hand to achieve a basic gripping function.

Synergistic terminal motor end-to-side nerve graft repair: investigation in a non-human primate model.

End-to-side nerve repair has re-emerged in the literature in recent years but clinical applications for this technique are not yet fully defined and clinical reports are rare and controversial. Hypothetically, there might be useful functional results performing peripheral end-to-side nerve graft repair using synergistic terminal branches with defined motor function. An end-to-side nerve graft repair bridging from the terminal motor branch of deep branch of the ulnar nerve to the thenar motor branch of the median nerve was performed in non-human primates. The results in this non-human primate model demonstrate the efficacy of end-to-side nerve graft repair at the level of peripheral terminal motor branches. End-to-side neurorrhaphy may present a viable alternative in conditions of unsuitable end-to-end coaptation and inappropriate nerve grafting procedures.

The midbrain dopaminergic cell groups in the baboon Papio ursinus.

The present study evaluates the cytoarchitecture of midbrain dopaminergic regions in baboons using similar methodology to that recently applied to compare humans and rats. This information is relevant for the interpretation of nonhuman primate models of Parkinson's disease (PD). The midbrains of four alpha male baboons were serially sectioned into 10 evenly spaced series of 50 microm sections. Series were stained with either cresyl violet or immunohistochemically reacted for tyrosine hydroxylase, substance P, calbindin-D28k, or parvalbumin. The organization of dopaminergic cell groups and the distribution of proteins within these groups were found to be very similar to that previously described in humans [McRitchie et al., J. Comp. Neurol. 364:121-150; 1996]. Dorsal and ventral tiers of the A9 substantia nigra (SN) pars compacta and all divisions of the A8 and A10 cell groups were identified revealing a high degree of homology in the arrangement of chemically distinct midbrain neurons between primates. The major difference between the organization of human and baboon midbrain dopaminergic neurons is the anteroposterior extent of the dense cell clusters within the SN pars compacta. In baboons the dorsomedial cell cluster is absent at posterior levels. The ventral tier cell clusters, which are targeted by PD in humans, are restricted to the posterior and ventral regions of the SN pars compacta of the baboon. In humans these cell clusters are found throughout the rostrocaudal extent of the SN. These ventral cell clusters have been previously shown to have reciprocal connections with sensorimotor regions of the putamen.

Soluble-fibre concentrate lowers plasminogen activator inhibitor-1 in baboons (Papio ursinus).

The effects of a soluble NSP (fibre) concentrate (SFC) on plasma fibrinogen and plasminogen activator inhibitor-1 (PAI-1), serum and liver lipids and lipoproteins and glucose tolerance were compared with those of bezafibrate (BF), a lipid-lowering drug, in obese baboons (Papio ursinus). The basal diet was a high-fat (37% of total energy), low-NSP (12.4 g/d) Westernized diet, supplemented for 8 weeks with either 20 SFCg/baboon per d or 6.7 mg BF/kg body weight per baboon per d. SFC supplementation significantly lowered PAI-1, total serum cholesterol, HDL-cholesterol and circulating free fatty acid levels. BF significantly lowered total serum cholesterol, but unexpectedly raised serum triacylglycerol levels. Although not statistically significant, the mean liver triacylglycerol concentration of baboons fed on BP was lower than that of baboons fed on SFC supplements. These results suggest that: (1) the mechanism of action of the two cholesterol-lowering treatments differ, with BF having a liver triacylglycerol-lowering effect and (2) the SFC ahd additional beneficial effect on fibrinolysis by lowering PAI-1 levels.

Venom of a six-eyed crab spider, Sicarius testaceus (Purcell, 1908), causes necrotic and haemorrhagic lesions in the rabbit.

By employing haematological, histological and isotope studies on rabbit, it was shown that envenomation by the South African crab spider, Sicarius testaceus, results in tissue necrosis and a marked increase in the permeability of the blood vessels in the vicinity of envenomation. The venom also acts systemically, which results in petechial bleeding of some viscera, thrombocytopaenia and elevated fibrinogen levels. Rabbit envenomation by this species results in a dramatic drop of the platelet count, without haemolytic anaemia. Should these parameters be the same in humans, they may serve as a yardstick to distinguish presumptive S. testaceus envenomation from that of Loxosceles.

Comparison between physiological effects of konjac-glucomannan and propionate in baboons fed "Western" diets.

Dietary fiber and resistant starch are fermented by colonic bacteria to short-chain fatty acids (SCFA) such as acetic, butyric and propionic acid, which the colon absorbs. It has been suggested that the beneficial metabolic effects of dietary fiber may be mediated through propionate. We therefore compared the effects of a soluble dietary fiber concentrate, konjac-glucomannan (K-GM), and of propionate on plasma fibrinogen, serum and liver lipid, glucose tolerance, insulin response and liver glycogen in baboons. Twelve male baboons were fed a "Western" diet with or without K-GM (5%) or sodium propionate (2%) supplements for periods of 9 wk in a crossover, randomized order, with stabilization periods in between. Measurements were taken at baseline and after 4 and 9 wk of each study period. After 9 wk, total serum cholesterol levels were significantly higher than pretest values when baboons consumed the unsupplemented Western diet (25%, p less than 0.05) or the propionate diet (17%, p less than 0.05). Konjac-glucomannan prevented this increase. The high density lipoprotein cholesterol concentration increased with all experimental diets (p less than 0.05). The percentage of total cholesterol as high density lipoprotein cholesterol, was significantly higher with K-GM supplementation than with the other diets. Konjac-glucomannan supplementation also resulted in lower than baseline values for triglycerides (p less than 0.01) and circulating free fatty acids (p less than 0.05) after 9 wk. Only the propionate diet raised serum triglycerides significantly (by 6%) above baseline. Liver cholesterol concentration was 31-34% lower, and the area under the glucose tolerance curve was smaller with K-GM and propionate diets (p less than 0.05) than with the unsupplemented diet.(ABSTRACT TRUNCATED AT 250 WORDS)