The third nerve transection and regeneration in rats with preliminary results on the sixth nerve transection and regeneration in guinea pigs

The relationship between the phenomenon of the nonselective reinnervation and the functional recovery after section and repair of the highly organized third cranial nerve motor system in rats was studied. The same relationship after section and repair of the more simply organized sixth cranial nerve motor system in guinea pigs is presented as preliminary results. Anatomical demonstration of nonselective reinnervation was obtained by injecting horseradish peroxidase (HRP) into the extraocular muscles. A bilateral reinnervation of previously ipsilateral innervated muscles both in the third and the sixth nerve was interpreted as a plastic response of the brain stem neurons to the nerve injury. Functional recovery, evaluated by measuring with an infrared light technique the horizontal and vertical vestibulo-ocular reflexes, was excellent for the rectus lateralis muscle while it was relatively poor i.e. partial for the muscles depending on the third nerve. These data suggest that one of the most important factors influencing the functional recovery after section and repair of a peripheral nerve is the complexity of the nerve motor system organization.

Early changes in cerebrospinal fluid Ca2+ and FFA levels following experimental spinal cord injury

Cerebrospinal fluid (CSF) Ca2+ and free fatty acids (FFA) levels were determined for 4 h following experimental spinal cord (SC) injury in rabbits. The injury was produced by dropping a 20 g weight from 20 cm on exposed dura mater at the C5-C6 level. Samples of CSF were obtained from the cisterna magna from a second laminectomy at the C1 level. A significant decrease in CSF Ca2+ levels was observed 10 and 30 min post-injury; such levels increased above normal values 180 min post-injury. A significant increase in CSF FFA levels was seen from 10 to 240 min post-injury with a peak at 30 min. The early decrease of CSF Ca2+ levels and the concomitant increase in CSF FFA levels seem to confirm in role of Ca2+ in mediating the lipolytic response of the SC tissue to trauma.

Retrograde degeneration of corticospinal axons following transection of the spinal cord in rats. A quantitative study with anterogradely transported horseradish peroxidase

The extent of the retrograde degeneration of corticospinal axons following transection of the spinal cord was studied in rats by labeling corticospinal axons with anterogradely transported horseradish peroxidase injected in the sensorimotor cortex. Axotomized corticospinal axons underwent progressive and continuing retrograde degeneration. In specimens examined 5, 14, 28, and 56 days after trauma, the tips of the transected corticospinal axons were seen to terminate at 181 +/- 80 microns, 977 +/- 203 microns, 1751 +/- 344 microns, and 2559 +/- 466 microns (mean +/- standard deviation), respectively, from the site of transection. The rate of retrograde degeneration varied according to the interval after spinal cord transection, as follows: 36.2 microns/day during the first 5 days; 88.4 microns/day between 5 and 14 days; 55.3 microns/day between 14 and 28 days; and 28.8 microns/day between 28 and 56 days. These findings may serve as useful parameters for the objective assessment of therapeutic modalities in spinal cord injury research.

Peripheral nerve autografts to the rat spinal cord: a study of the origin of regenerating fibres using fluorescent double labelling

In adult Wistar rats a segment of the right sciatic nerve was grafted to the right dorsal funiculus of the spinal cord (SC). After survivals of 25-54 weeks a solution of the retrograde fluorescent cytoplasmatic tracer Fast Blue (FB) was injected into the SC and microgranules of the retrograde fluorescent nuclear tracer Diamidino Yellow (DY) were inserted into the graft. DY labelled neurones were found in the SC up to 30 mm both rostrally and caudally to the graft and were always single labelled. DY labelled cells were also found in the dorsal root ganglia (DRG) for 6-7 consecutive levels caudally to the graft. Ten to 30% of the DY labelled DRG cells were double labelled and also contained the FB tracer. The present work using the multiple retrograde fluorescent tracing method demonstrates that peripheral nerve (PN) grafts implanted in the rat SC are reinnervated by axones arising from intrinsic SC neurones and DRG cells. The axones from intrinsic SC neurones seem to result only from the regrowth of damaged neurones which have lost their intraspinal projections. The regeneration from DRG cells seem to be sustained by both the regrowth of damaged axones and the preterminal and/or collateral sprouting.

Normal rhodanese activity in leukocytes from Leber patients: enzyme characterization and activity levels

The thiosulfate:cyanide sulfurtransferase (rhodanese) enzyme (EC 2.8.1.1.) was studied in human leukocytes from control subjects and from nine patients with Leber's hereditary optic atrophy. Enzyme activity was proportional to protein concentration in the tested range (0.09 to 0.39 mg) as well as to incubation time. The optimal pH for reaction was 8.7 and the apparent Km for thiosulfate was 7 X 10(-3) M. No significant difference of enzyme activity was present in Leber's disease.

Vasoconstriction of the basilar artery in rabbits: the vasoconstrictor activity of blood, CSF and blood-CSF mixtures incubated for varying periods of time

After subarachnoid haemorrhage, the amount of blood in the subarachnoid space and the time elapsed since the haemorrhage seem important factors in predicting the occurrence of vasospasm. In this experiment we studied the responses of the rabbit basilar artery to acute topical application of samples of human cerebrospinal fluid (CSF), mixtures of blood and CSF incubated at 37 degrees C for 0 to 12 days. The degree and the duration of the vasoconstriction depended on the time of incubation and on the concentration of blood in the samples. Samples incubated for five and seven days caused severe and long-lasting vasoconstrictions. Samples incubated for 0, 1, 3, 8, 10 and 12 days caused slight or moderate and short-lasting vasoconstriction. Samples incubated for 5, 7, 8, and 10 days showed a linear relationship between the concentration of blood and the degree of constriction up to the blood-CSF ratio of 0.6 to 1 (blood content of 37.5%); further increases of blood concentration did not cause further vasoconstriction. This phenomenon may be related to the saturation of arterial receptors. The course of the vasoconstriction using samples with different blood concentrations suggests the existence of more vasoactive substances. This work seems to confirm the importance of blood concentration in the CSF and of time as factors governing the development of vasospasm.

Oculomotor nerve regeneration in rats. Functional, histological, and neuroanatomical studies

To study oculomotor nerve regeneration in rats, the oculomotor nerve was approached microsurgically and was sectioned at the base of the skull. The nerve stumps were reapproximated and affixed with a plasma clot in Group I animals and were separated by a gap in Group II animals. Visceral eye motility was evaluated weekly between 1 day and 40 weeks after surgery by recording the pupillary diameter under standardized photic stimulation. Somatic eye motility was assessed after 26 weeks by measuring the ocular displacement evoked by vestibular stimulation in the horizontal and vertical planes. Nerve regeneration was documented histologically and morphometrically at 8, 16, and 40 weeks after section. The selectivity of axonal regeneration to the extraocular muscles was investigated after 26 weeks by mapping (with injection of retrograde horseradish peroxidase) the motoneurons that supplied each reinnervated muscle. Between 6 and 20 weeks after section, the pupil diameter showed a progressive reduction in Group I rats, and no changes were observed in Group II rats. Compared with normal rats, the amplitude of horizontal and vertical ocular displacements was decreased, respectively, by 30% and 45% in Group I and by 65% and 80% in Group II. In Group I rats, the vestibular stimulation in the horizontal plane evoked anomalous eye movements with vertical components. On histological examination, regenerated nerves showed a progressive increase of axonal diameter and myelin-sheath thickness. Reinnervated muscles were associated with a less specific, bilateral representation in the midbrain compared with normal muscles, which have unilateral representation. The changes of the somatotopic organization were interpreted as being the result of the misdirected regrowth of axons in the postlesional nerve stump and of the collateral sprouting in the midbrain.

Epiperineurium-fascial stitches along the stumps of a transected nerve. An additional method for closing the gap in the nerve trunk

Following peripheral nerve repair, tension on the suture line is regarded as an important factor in producing scar tissue. In some cases, one or more microsurgical epiperineurium-fascial stitches (EPFS) along the proximal and distal stumps of a transected nerve permit their firm approximation, shifting tensile forces from the suture line over longer segments of the nerve stumps. This simple method was used to treat three ulnar and two cranial nerve lesions with gaps ranging from 8 to 20 mm with an end-to-end suture, avoiding any tension on the suture line. In all cases, functional recovery was satisfactory.

Sleep palsy (Saturday-night palsy) of the deep radial nerve. Case report

A patient with a long-recognized asymptomatic lipoma adjacent to the deep radial nerve developed paralysis of this nerve from a compression similar to the sleep palsy, or "Saturday-night palsy," mechanism.

Total excision of spinal lipomas using CO2 laser at low power. Experimental and clinical observations

Total excision of spinal lipomas (SL) is difficult because of the intimate adhesion between the fibro-adipose tissue and the neural structures. Radical surgery in SL can provoke nervous lesions; therefore many authors recommend only partial excision as a means of decompression. Nevertheless the role of traction or tethering of the spinal cord in all spinal disraphism, including SL, is known to be very important in determining the clinical picture. So partial removal of SL cannot be effective in releasing the tethered cord. The use of a CO2 laser at low power (3-5 W) permitted radical surgery without any neural damage and complications in 2 adult patients with large, not well capsulated SL. These patients were previously operated on by the same surgeon with conventional microsurgical techniques for partial excision. After CO2 laser surgery there was significant improvement of the clinical pictures, the follow-up being respectively 24 and 36 months. This clinical experience was performed after a CO2 laser had successfully been used in an experimental model in rats simulating a condition of SL. Using power of 3-5 W was not sufficient to attain an immediate vaporization, but the adipose tissue first changed into a transparent liquid across which it was possible to recognize the interfaces between the neural structures and the adipose tissue.

Peripheral nerve autografts to the rat spinal cord: study on the origin and course of regenerating fibres

Autologous sciatic nerve grafts were implanted to the lower thoracic spinal cord (SC) of adult rats. The grafts were longitudinally placed on both sides of the SC midline over the dura mater and their cut ends were inserted into the dorsal white matter of the SC. Eight to 60 weeks later the grafts were exposed. In a first experimental group (A) either horseradish peroxidase (HRP) or lectin conjugated horseradish peroxidase (WGA-HRP) was injected into the grafts in order to investigate the origin and the course of regenerated fibres entering the grafts. In a second experimental group (B) the SC was acutely transected between the upper and lower graft insertions and either HRP or WGA-HRP was injected into the caudal stump of the SC in order to investigate the ability of regenerating axons once entered the grafts to re-enter the SC. In group A retrogradely labelled cells were found in the SC scattered in proximity of both the caudal and rostral graft insertions and in the ventral horns as far as 30 mm rostrally to the grafts. Labelled cells were also located in the spinal ganglia, at the level of the grafts and up to 6 segments caudal to them. In group B retrogradely labelled cells were present in the SC rostrally to the transection, both in proximity of the upper graft insertions and in the ventral horns as far as 30 mm rostrally to the grafts. These findings demonstrate that PN grafts implanted to the SC of adults rats can be innervated by regenerated axons arising from both intraspinal neurons and dorsal root ganglion cells (group A); furthermore axons from intraspinal neurons entered and elongated in the grafts can re-enter the SC (group B).

Changes in the central representation of the extraocular muscles in the rat oculomotor nucleus after section and repair of the third cranial nerve

The anatomical location of motoneurons controlling the extraocular muscles within the oculomotor nucleus was investigated by injecting retrograde horseradish peroxidase (HRP) into individual eye muscles in control rats and in rats submitted to intracranial section and repair of the oculomotor nerve 6 months previously. Compared to the controls, the operated animals showed marked changes in the somatotopic organization of the oculomotor subnuclei. The possible nature of this re-arrangement is discussed.

Connective tissue scarring in experimental spinal cord lesions: significance of dural continuity and role of epidural tissues

Neoformation of connective tissue occurring at the level of spinal cord injury is considered a factor in the failure of regeneration in the mammalian spinal cord. The purpose of the present research was to experimentally investigate the origin and characteristics of connective proliferation following spinal cord lesion produced by compression in the rat. The role of the dural sheath and that of the tissues surrounding the spinal cord were studied. In one group of animals (1), the dura mater was left intact; in a second group (2) a transverse incision of the dura was performed at the level of the spinal cord compressive lesion. In group (1) a few collagenous fibres were seen within the lesion but no connective septum was observed. In group (2) a transversely orientated septum of fibrous scar tissue was constantly found within the lesioned cord. Our experimental study shows that: 1. dural continuity prevents the formation of connective tissue scarring and limits fibrous reactions in the epidural space; 2. opening of the dural sheath is followed by a vigorous fibroblastic reaction in the epidural tissue which extends into the spinal cord to form a connective septum.

Peripheral nerve autografts to the injured spinal cord of the rat: an experimental model for the study of spinal cord regeneration

Regenerated central axons have been shown experimentally to penetrate in peripheral nerve segments transplanted into the spinal cord (SC). However, if the nerves are transplanted between the stumps of the transected SC regeneration is impaired by local cavitation and scarring. Our experiment was designed to study whether nerve grafts bridging a severe transverse SC lesion might provide to central regenerating axons a pathway to by-pass the lesion. To this purpose, 2 segments of autologous peripheral nerves were inserted through small dural openings into dorsal longitudinal myelotomies rostral and caudal to a transverse SC lesion in rats. Eighteen weeks after transplantation a large number of well myelinated fibres filled the grafted nerves. Only a few of these fibres, however, could be followed into the SC; they were located in the outer layers of the dorsal white matter. The problems regarding the origin and destination of these fibres are discussed.

Familial Richner-Hanhart syndrome: genetic, clinical, and metabolic studies

The genetic, clinical, and metabolic studies of two familial cases of Richner-Hanhart syndrome (type II hypertyrosinemia are described and the findings compared with other familial cases of palmo-plantar keratoderma. The clinical pictures are identical except that in the latter there are not ocular symptoms and the tyrosine levels are not raised. One of the two patients examined was treated with a diet low in tyrosine and phenylalanine with immediate improvement in clinical symptomatology and complete disappearance of the dendritic keratitis.

Alternative to tarsorrhaphy in peripheral facial nerve palsy with expectation of functional recovery. Technical note

A simple technique is described for protecting the cornea in patients with peripheral facial nerve palsy while waiting for recovery of nerve function. The application of an adhesive strip to the superior eyelid permits opening and closing of the eye, and provides good protection of the cornea.

Sanfilippo type C diagnosis: assay of acetyl-CoA: alpha-glucosaminide N-acetyltransferase using [14C]glucosamine as substrate and leukocytes as enzyme source

We describe an assay for acetyl-CoA: alpha-glucosaminide N-acetyltransferase using purified [14C]glucosamine as substrate, and leukocytes as enzyme source. The assay is suitable for the diagnosis of homozygous and heterozygous carriers of Sanfilippo syndrome type C.

Mucopolysaccharidosis III B: hybridization studies on fibroblasts from a mild case and fibroblasts from severe patients

Cell fusion with polyethylene glycol (PEG) was performed on fibroblasts from a previously studied patient with a mild form of Sanfilippo B disease and altered residual enzyme activity and fibroblasts from several patients with the classical, severe form of the disease. No complementation was found in heterokaryons. This suggests that the mild phenotype in our patient can be ascribed to an allelic mutation.

Anderson-Fabry's disease: neuropathological and neurochemical investigation

A clinical, neuropathological and neurochemical study of a case of Anderson-Fabry's disease is described. The clinical course mainly consisted of repeated ictus with major involvement of the CNS. The neuropathological examination is dominated by severe alterations in the cerebral vessels due to glycolipid deposits on the walls, with reduction or occlusion of the lumen. This is correlated with secondary ischaemic foci scattered throughout the cortex as well as through the white matter. In addition, the cells of the cerebral cortex, thalamus, basal ganglia, amygdala, cerebellar and olivary nuclei show a marked accumulation of lipofuscin. Biochemical examination reveals a threefold increase in galactolipids due to the specific alpha-galactosidase deficiency. Cholesterol is reduced secondarily to ischaemic myelin damage. Glycosaminoglycans uronic acid is increased in cytosol and membrane-bound fractions which could be related to reactive gliosis. Glycoprotein sugars show a decrease in N-acetyl-neuraminic acid and fucose as well as an increase in hexosamines and hexoses in membrane-bound fraction, while in cytosol fraction all sugars are increased. This suggests that the alpha-galactosidase deficiency can alter not only the glycolipid but also the glycoprotein metabolism, resulting in a higher presence of hexosamines and hexoses-rich glycoproteins.