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Biomedical subjects

A R Hudson

Publications and source records attributed to A R Hudson.

At least 73 records · Page 4Linked to original sources
PubMed1984

Perineurioma (localized hypertrophic neuropathy).

Three patients with localized hypertrophic neuropathy ( LHN ) had a painless, slowly progressive mononeuropathy over many years, resulting in severe focal neurologic deficit. Grossly, the affected nerves showed a fusiform enlargement. Histologically, there was loss of nerve fibers, disorganization of the fascicular pattern, and proliferation of elongated cells with whorl formation. These cells exhibited no immunoreactivity for S-100 protein, and ultrastructural features set them apart from Schwann's cells. We conclude that LHN is not a disorder caused by hyperplasia of Schwann's cells but a benign peripheral nerve tumor of perineurial cell origin. This study also suggests that perineurial and Schwann's cells may not derive from the same precursor element.

Adult↗
PubMed1984

Nerve injection injuries.

Nerve injection injury is preventable. There is now a reasonable basis for management of the unfortunate victims, should an accident occur. Practitioners who follow the basic steps of management will both aid their patients and also allow them to give a better account of themselves in the medicolegal setting.

Humans↗
PubMed1983

Computed tomography of sphenoid sinus mucocele.

The clinical presentation of sphenoid sinus mucocele is usually dependent on the degree of involvement of adjacent structures. Since extension can be in any direction, there is a wide spectrum of symptomatology and clinical diagnosis can be difficult. Five cases of sphenoid sinus mucocele, four of which were demonstrated by computed tomography (CT), are presented. CT with its multiplanar display capability, is the diagnostic procedure of choice. It not only demonstrates the extent of the lesions non-invasively, but its ability to demonstrate bony expansion and destruction as well as density and enhancement pattern, will obviate the need for tomography. It has the greatest potential for differentiating other sphenoid and parasellar lesions.

Adenoma↗
PubMed1982

Massive gastroduodenal hemorrhage and perforation in acute spinal cord injury.

Fatal gastrointestinal hemorrhage or perforation are important problems in the management of patients in the acute phase of spinal cord injury. This paper describes 3 patients with these conditions, and shows some of the associated hazards, especially the danger of painless penetration, perforation, and peritonitis, plus the increased morbidity of these serious problems in the presence of the neurological sequelae of spinal cord injury. Our experience shows that life-threatening hemorrhage from the gastrointestinal tract occurs in about 2.5% of patients with cord injury, and often occurs during the first few days after the accident. We believe that a high index of suspicion and an aggressive therapeutic approach are necessary to save these patients from the traditionally high mortality associated with massive upper gastrointestinal hemorrhage, especially during this critical period of acute spinal cord injury.

Acute Disease↗
PubMed1982

Peripheral nerve injection injury with steroid agents.

The possible neurotoxic effects of five commonly used steroid agents were examined. Using histologic studies and studies of the microneural circulation, it was found the steroids can indeed cause neurotoxicity. The injection site was critical in effecting injury. Only intrafascicular injection caused damage. The damage produced varied with the agent used. Dexamethasone (Decadron) caused minimal damage, while hydrocortisone (Solu-Cortef) and triamcinolone hexacetonide (Aristospan) caused widespread axonal and myelin degeneration. Disturbance in the blood-nerve barrier correlated with the changes noted on light and electron microscopy, but is thought to be coincidentally and not causally related. In conclusion, it was shown that the intrafascicular injection of commonly used steroid agents had a direct toxic effect on peripheral nerve-fibers and caused a disruption of the blood-nerve barrier. Use of the more toxic agents in the vicinity of peripheral nerves should probably be avoided.

Animals↗
PubMed1981

Intraneural ganglion: a case report with electron microscopic observations.

We report a case of common peroneal mononeuropathy caused by an intraneural ganglion in a 9-year-old boy. The mass and the contiguous nerve fascicles were excised under the operating microscope. Histologically, the cyst wall was composed of layers of elongated cells merging with fascicles that exhibited changes suggestive of a pressure-ischemia effect. Electron microscopy showed that the cells forming cyst wall were myofibroblasts, similar to the cells found in ganglia arising from joints elsewhere in the body. A review of the English literature on intraneural ganglia discloses 44 additional cases, of which 86% involved the common peroneal nerve. The most common clinical feature was motor dysfunction (followed by pain, sensory loss, and the presence of a palpable mass), and a significant male predominance is noted. The pathogenesis of this nerve lesion is discussed in light of our findings.

Child↗
PubMed1981

Experimental study of fascicular nerve repair with and without epineurial closure.

Microscopic fascicular repair without closure of epineurium was compared with microscopic epineurial repair in 12 rhesus monkeys. Measurements of evoked nerve action potentials, and responses to repetitive and tetanic stimulation made at one interval 3, 6, 9, or 12 months postoperatively, were compared to baseline preoperative studies. Histological evaluation included light and electron microscopic preparations and studies of distal stump myelinated fiber maturity. Electrical measures of regeneration indicated that recovery was more advanced in the limb with epineurial repair in eight animals, whereas in four there was no difference between fascicular and epineurial repair. Fascicular repair appeared not to fare as well as epineurial repair because, although neuromas developed with both, the length of the neuroma was greater with fascicular than with epineurial repair. The relatively lengthy neuroma in the nerve with fascicular repair was due to axonal disorganization and connective tissue proliferation along the length of the dissection necessary for the repair. Nonetheless, studies of myelinated fiber distribution in the distal stump showed no significant differences. Similar studies were conducted in 11 primates, where epineurial repair was matched with fascicular repair in which the epineurium was closed. Here, regeneration as measured by both electrical and histological studies was comparable. Histological study showed less disorganization at the repair site in the nerve with fascicular suture and epineurial closures than in that with epineurial suture. However, studies of distal stump myelinated fiber maturity demonstrated no significant differences. Thus, there seems to be no advantage in either resecting or closing epineurium in fascicular nerve repair.

Action Potentials↗
PubMed1980

Clinical and experimental aspects of injection injuries of peripheral nerves.

Injury to peripheral nerves complicating deep intramuscular injections of antibiotic and other agents is well recognized and can result in significant permanent neurological deficit. The purpose of this paper is to review the subject of nerve injection injuries, and report on a series of recent experimental studies carried out in this laboratory designed to improve our understanding of the pathophysiology of this condition and help provide a rational basis for its treatment. A wide variety of chemotherapeutic, prophylactic, and local anaesthetic agents in common use were injected into the sciatic nerve of the adult Wistar rat. Both intrafascicular and extrafascicular injections were examined. Results revealed that the site of injection was the most crucial factor in determining the degree of nerve fiber injury. Following intrafascicular injection, the degree of injury varied significantly, depending upon the specific agent injected. The most severe injuries were associated with wide-spread axonal and myelin degeneration. Pathological alterations in the nerve were evident as early as 30 minutes following injection injury. Regeneration was a constant finding in nerve damage by injection of the various agents. The mechanism of injury appeared to be a direct toxic effect of the injected compound on neural tissue, with an associated break down of the blood-nerve barrier.

Anesthetics, Local↗
PubMed1980

Early changes following injection injury of peripheral nerves.

Using light and electron microscopy and a fluorescent tracer technique, the authors have studied various aspects of injection injuries to nerves in an attempt to elucidate the pathophysiology of this condition and to help establish a rational basis for treatment. In 72 animals 144 nerve injections were carried out, using five drugs in current use and commonly administered by intramuscular injection. The nerves were examined at varying times (10 minutes to 10 weeks) following injection. Pathological alterations in the nerve were evident as early as 30 minutes after injection. The mechanism of injury appears to be a direct neurotoxic effect on the nerve fibre-both axon and Schwann cell-with a breakdown in the blood-nerve barrier.

Animals↗
PubMed1979

Complex formation between selenium and methylmercury.

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.

Animals↗
PubMed1979

Experimental interfascicular nerve grafting.

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.

Action Potentials↗
PubMed1979

Histological studies of experimental interfascicular graft repairs.

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.

Animals↗
PubMed1979

Iatrogenic femoral nerve injuries.

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.

Adolescent↗