Biomedical subjects
Publications and source records attributed to A R Hudson.
Methylmercury, after incubation at 3k7 degrees C and pH 7.0 with selenite in the presence of rat erythrocytes, can be extracted into benzene as an unstable 2 : 1 complex with selenium. The same complex, possibly bis-methylmercury selenide, is formed when methylmercury is treated with hydrogen selenide at pH 7.0 in the absence of erythrocytes.
Twenty-nine adult rhesus monkeys underwent complete laceration of both tibial nerves at mid-thigh level and repair by different methods to study the relative efficacy of autogenous interfascicular nerve grafts. Sixteen animals in Group I had an interfascicular graft repair using short sural nerve autografts on one limb and fascicular repair without grafts on the other limb. Thirteen animals in Group II, after having a 1-cm segment of tibial nerve resected, had an interfascicular graft repair without tension in one limb and an epineurial repair under moderate tension in the other limb. Evoked nerve and muscle action potentials and muscle strenght in response to repetitive and tetanic stimulation were recorded as baseline values prelaceration and then on re-exploration at 4, 6, 9, or 12 months. All nerves were examined by light and electron microscopy. Electrophysiological data, particularly muscle strength response, showed non-graft repairs to be superior at 4 and 6 months of regeneration. However, by 9 and 12 months the graft repairs had caught up and were equal to the non-graft repairs. Histologically, it was observed that many axons missed the graft segments and were present in extrafascicular connective tissues. Nonetheless, enough axons regenerated to the distal nerve to explain the success of these relatively short grafts. From the results of these experiments, it is concluded that use of autogenous interfascicular grafts offers no advantage over end-to-end non-graft repair. When and end-to-end repair cannot be achieved, use of short interfascicular nerve grafts is feasible and will work.
Biopsies of sutured and grafted primate peripheral nerves were examined by light and electron microscopy after the final set of electrical measurements had been recorded. Inspection of all proximal stumps showed the expected regenerative activity which was not affected by the nature of the nerve repair. Transverse sections through the epineurial, interfascicular, and graft suture lines showed a similar pattern in all animals and at this site nerves sutured by epineurial technique could only be distinguished from those sutured by fascicular technique by loci of the non-absorbable suture. Fascicular repairs, whether done fascicle-to-fascicle or with interposition of grafts, had a more lengthy neuroma than did the epineurial repairs. Maintenance of fascicular architecture through the course of the grafts was variable. Fascicular structure was frequently absent in the central graft segments and in segments close to the second suture site. The method of repair used more proximally could not be distinguished by evaluation of distal stump segments. Measurements of myelinated fiber size made of distal stump axons revealed no statistical difference between the methods of repair.
Eighteen cases of iatrogenic femoral nerve injury are described. In two patients the damage was incurred as a result of an intra-abdominal operation. In three others the nerve was injured at the level of the inguinal ligament. In the majority femoral nerve palsy followed surgery to the hip joint and was attributable to a lesion-in-continuity. Only one of the patients in the series made a full recovery, but because only severe cases were included these disappointing results by no means represent the expected outcome. To avoid this serious and distressing complication of surgery, the surgeon must be familiar with the anatomic features of the region and must take care to avoid compression of the femoral nerve by retractors and its overstretching during operations on the the hip joint.
Explore the source record for details and available documents.
A number of cases are presented to illustrate the diagnostic effectiveness of computed tomography in the cervical spine and spinal cord, specifically in syringomyelia, spinal stenosis, and fractures. Certain limitations in the examination are also presented, and problems related to interpretation, particularly in regard to spinal stenosis, are discussed.
A 37-year-old with a history of postpubertal arrest of sexual development and delayed growth was found to have an enlarged sella turcica. The clinical and biochemical features were consistent with hypopituitarism. A tumor was removed transsphenoidally that, through light microscopy, histochemistry, and electron microscopy, proved to be a paraganglioma. We report the possible origin of intrasellar paraganglioma, as well as the pathogenesis of hypopituitarism.
A 28-year-old man shot himself in the left posterior triangle of the neck with a shotgun. At the initial operation secondary repair of the resultant brachial plexus injury was decided upon in view of the difficulty in assessing lesions in continuity at this point after injury. The patient had total brachial plexus palsy. Nine weeks after the injury sensory and motor function were returning and the only element of the brachial plexus not showing evidence of nerve fibre continuity was the musculocutaneous nerve. Sural nerve autografts were sutured between the trimmed proximal and distal stumps of this nerve. By 4 months after the injury there was further improvement in both sensory and motor function, and by 18 months there was sensation in the autonomous zones of both median and ulnar nerves and good return of muscle power.
Of 101 patients with acute injury to the cervical spine below the level of the axis, 74 were selected for anterior operation to ensure stability and comfort and to decompress the neural elements when indicated. Forty-six of the patients underwent a Cloward fusion at the level of the injury. Twenty-eight were treated by bar graft fusion. The indications for these procedures and the techniques involved are outlined. A successful operative result was achieved primarily in 65 of the 74 patients and eventually in 73 patients. The management mortality for patients treated by anterior operation was 2-7 per cent. The advantages of these procedures are the achievement of comfort, the facilitation of early rehabilitation, the maintenance of bony alignment and the preservation and maximal recovery of neurological function.
A review of the local neuropathological factors suggests that in lesions-in-continuity, the timing of surgical intervention should be predicated by the histological structure of that particular lesion-in-continuity. This cannot be derived by inspection or palpation of the lesion. The information must be gained from clinical and electrical studies. In the case of the divided nerve, the interrupted fascicles should be sutured as soon as the longitudinal extent of the injury can be accurately determined. The ultimate factor limiting the successful outcome of delayed peripheral nerve surgery is probably related to the state of the end organs and muscle fibers.
Guinea pigs were exposed to aerosols of 0.1 mg of Salmonella typhosa endotoxin per ml for 2 or 4 hours, and white cells in blood and in bronchopulmonary lavage were counted at 2, 4, and 6 hours. The lungs of a second group of guinea pigs and hamsters exposed in the same manner were fixed in inflation with osmium tetroxide in fluorocarbon, which retains cells on luminal surfaces of airways. The polymorphonuclear leukocyte counts in cardiac blood were significantly increased, and lymphocyte counts were decreased at 6 hours (P less than 0.05). The number of cells obtained by bronchopulmonary lavage, which were mostly polymorphonuclear leukocytes, increased at 4 hours to 28 million, and at 6 hours, was 26.5 million (P less than 0.01), compared to 5 million cells at the same times in air and in water aerosol control preparations. The polymorphonuclear cell counts on airway cross sections, i.e., (polymorphonuclear cells/epithelial cells) x 100, showed a mean +/- SD peak of 53.9 +/- 10.9 after 4 hours in guinea pigs and a peak of 99.7 +/- 11.0 after 6 hours in hamsters. Alveoli showed no cell recruitment. Platelets were aggregated on surfaces of arterioles facing bronchioles, although counts in blood were unchanged. Neither leukocytes nor airway cells showed damage to their ultrastructure. The time course for airway recruitment and leukocytosis matches that for symptoms after exposure of workers to dusts from natural fodder or fibers. This suggests that leukocyte recruitment to airways by inhaled endotoxin may be part of the mechanism for the fever and chest tightness in occupational disorders.
Light and electron microscopical examination of a pituitary adenoma showed that the tumor was composed of prolactin cells that produced amyloid-like material. The findings have been interpreted in favor of the role of rough endoplasmic reticulum in amyloid fibril formation within the adenoma cells. Histochemical and fine structural data indicate that the material produced by this tumor resembles apudamyloid rather than immunoamyloid.