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Biomedical subjects

C E Rhoades

Publications and source records attributed to C E Rhoades.

13 recordsLinked to original sources
PubMed1993

Effects of local compression on peroneal nerve function in humans.

A new apparatus was developed to compress the anterior compartment selectively and reproducibly in humans. Thirty-five normal volunteers were studied to determine short-term thresholds of local tissue pressure that produce significant neuromuscular dysfunction. Local tissue fluid pressure adjacent to the deep peroneal nerve was elevated by the compression apparatus and continuously monitored for 2-3 h by the slit catheter technique. Elevation of tissue fluid pressure to within 35-40 mm Hg of diastolic blood pressure (approximately 40 mm Hg of in situ pressure in our subjects) elicited a consistent progression of neuromuscular deterioration including, in order, (a) gradual loss of sensation, as assessed by Semmes-Weinstein monofilaments, (b) subjective complaints, (c) reduced nerve conduction velocity, (d) decreased action potential amplitude of the extensor digitorum brevis muscle, and (e) motor weakness of muscles within the anterior compartment. Generally, higher intracompartmental pressures caused more rapid deterioration of neuromuscular function. In two subjects, when in situ compression levels were 0 and 30 mm Hg, normal neuromuscular function was maintained for 3 h. Threshold pressures for significant dysfunction were not always the same for each functional parameter studied, and the magnitudes of each functional deficit did not always correlate with compression level. This variable tolerance to elevated pressure emphasizes the need to monitor clinical signs and symptoms carefully in the diagnosis of compartment syndromes. The nature of the present studies was short term; longer term compression of myoneural tissues may result in dysfunction at lower pressure thresholds.

Adult↗
PubMed1992

Interspecies comparison of cellular localization of the cyanide metabolizing enzyme rhodanese within olfactory mucosa.

The observation of high levels of xenobiotic metabolizing enzyme activity in the olfactory mucosa has produced speculation on the functional significance of these enzymes in the nose. Hypothesized roles include protection of the nasal epithelium, lung, and other downstream tissues, and termination or modification of olfactory responses. The enzyme rhodanese metabolizes cyanide, which is a commonly inhaled toxicant and an odorant and therefore of interest to both toxicologists and olfactory neurobiologists. The cellular localization of this enzyme within the olfactory mucosa will have important consequences for its ability to protect specific cells, as well as its ability to alter the concentration of inhaled cyanide at receptors, and therefore could provide clues as to its function in this tissue. We have compared the distribution of this enzyme in two species, the rat and the cow, using immunohistochemical localization techniques employing species-specific polyclonal antisera raised in our laboratory. In the rat, rhodanese-like immunoreactivity was greatest within the apical portion of the sustentacular cells, the basal cells, and the duct cells of Bowman's glands. Very little to no reaction was observed in the acinar cells of Bowman's glands. In the cow, however, the acinar cells and duct cells of Bowman's glands showed intense immunoreactivity with little to no reaction observed in the sustentacular or basal cells. The differences in localization of rhodanese in these two species may have important implications for cell types at risk during inhalation of cyanide or organonitrile compounds metabolized to cyanide within the nasal mucosa.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

The cyanide-metabolizing enzyme rhodanese in human nasal respiratory mucosa.

The cyanide-metabolizing enzyme rhodanese is present in rat nasal epithelium at high activity levels. Cyanide is a common environmental pollutant. It is both toxic and an odorant. The high rhodanese activity in rat nasal epithelium may provide a mechanism for detoxicating inhaled hydrogen cyanide and may also play a role in olfaction by limiting the concentrations of cyanide in the nasal epithelium. The objective of this study was to determine whether high levels of rhodanese activity are also present in human nasal epithelium. On a per milligram mitochondrial protein basis, the rhodanese in human nasal tissue exhibited both a lower affinity (higher Km) for cyanide and a lower maximum velocity (Vmax) for cyanide metabolism than did rhodanese from rat nasal tissue. As in human liver, the human nasal enzyme appeared to exhibit substrate activation by cyanide. Rhodanese activity in the maxilloturbinates of nonsmokers was statistically higher than in smokers although only three samples per group were available. The Vmax/Km ratios for rhodanese from the nasal tissue of nonsmokers were consistently greater, thus suggesting the possibility of higher rates of cyanide metabolism in nonsmokers than in smokers.

Cyanides↗
PubMed1988

Internal vascularity of the scaphoid in cadavers after insertion of the Herbert screw.

This article describes the effects of various operative exposures for insertion of the Herbert screw on the internal vascularity of the scaphoid. Vessels supplying the proximal 70% to 80% of the scaphoid were intact in all specimens except one, which had a combined palmar and dorsal. approach. Vessels supplying the tubercle and the distal 20%-30% were disrupted in five of 18 specimens undergoing the palmar approach. The palmar approach did not disrupt the significant dorsal blood supply, and the dorsal approach was safe provided care was taken to preserve the visible dorsal vascular leash.

Bone Screws↗
PubMed1985

Dynamic compression for small bone arthrodesis.

A technique providing dynamic compression for arthrodesis of the small joints in the hand uses a longitudinal wire for alignment and two 0.045 Kirschner wires and methyl methacrylate cement for continuous dynamic compression. Thirty-one joints, 12 metacarpophalangeal and 19 interphalangeal, were arthrodesed by this method. There were no angular malunions or nonunions. The technique is recommended as an alternative to current fixation methods in the hand for small joint arthrodesis.

Arthrodesis↗
PubMed1985

Carpal tunnel syndrome: associated abnormalities in ulnar nerve function and the effect of carpal tunnel release on these abnormalities.

Twenty of 59 hands (34%) of patients with carpal tunnel syndrome had abnormalities in sensibility testing of both median and ulnar nerves by either two-point discrimination, Semmes-Weinstein monofilament testing, or both. Before surgery, 53% of patients complained of paresthesias and/or numbness in ulnar nerve distribution. Eighty percent of the hands had abnormal Semmes-Weinstein monofilament testing of the ulnar nerve. Thirty-five percent had abnormal two-point discrimination. Forty-one percent had abnormal electromyographic testing of the ulnar nerve. All hands had median nerve decompression alone. Guyon's canal was not released. After surgery, 89% of patients had improvement in paresthesias and/or numbness of the ulnar nerve. Ninety-four percent had improvement in Semmes-Weinstein monofilament testing. Eighty-six percent had improvement in two-point discrimination. Patients with a residual abnormality in ulnar nerve sensibility also had continued abnormality in median nerve sensibility. A significant percentage of patients with carpal tunnel syndrome also have signs and symptoms of ulnar nerve compression. Most improved with carpal tunnel release alone.

Carpal Tunnel Syndrome↗
PubMed1985

Results of internal neurolysis of the median nerve for severe carpal-tunnel syndrome.

Thirty-six hands in thirty-two patients had internal neurolysis of the median nerve and carpal tunnel release for severe carpal-tunnel syndrome. Median-nerve function was evaluated in all hands using Weber two-point discrimination and electromyography. Thenar-muscle strength or bulk, or both, were recorded in thirty hands. Ten hands also had Semmes-Weinstein monofilament pressure-testing. The indication for neurolysis in these selected patients was the presence of any one of the following: an increase in two-point-discrimination values, thenar-muscle atrophy, or denervation potentials in the thenar muscles. Twenty-two (76 per cent) of the twenty-nine hands that had had diminished two-point discrimination preoperatively regained normal sensibility. Seven (70 per cent) of ten hands that had had thenar-muscle weakness (grade 3 or less) preoperatively regained grade-4 or 5 strength. Nine (50 per cent) of eighteen hands that had had thenar-muscle atrophy regained normal muscle bulk. Seventy-six per cent of the patients in this series recovered sensation and 70 per cent recovered muscle strength, and the procedure was well tolerated. Although no studies comparing the results of treatment of severe carpal-tunnel syndrome with and without internal neurolysis have been reported, we think that neurolysis, if it is done by a surgeon who is skilled in microsurgery, is a safe and effective procedure for severe carpal-tunnel syndrome.

Adult↗
PubMed1984

Stenosing tenosynovitis of the fingers and thumb. Results of a prospective trial of steroid injection and splinting.

In a prospective study of conservative treatment of stenosing tenosynovitis of the fingers and thumb, 53 fingers and thumbs were injected with 1 cm3 of methylprednisolone and 1 cm3 of 1% lidocaine and immobilized for three weeks. Thirty-eight (72%) of the 53 digits had a successful outcome (mean follow-up period, 25 months). Fifteen (29%) digits in ten patients were only temporarily improved. Treatment was successful in most patients with symptoms and signs of less than four months' duration. Only 41% of the digits causing symptoms for greater than four months had a successful outcome. Patients with multiple-digit involvement did not respond as well (12 satisfactory and ten failed) as those with single-digit involvement (39 satisfactory and two unsatisfactory). The patient with stenosing tenosynovitis in a single digit with less than four months of symptoms responded most favorably to the conservative regimen.

Adult↗
PubMed1983

Diagnosis of post-traumatic syringohydromyelia presenting as neuropathic joints. Report of two cases and review of the literature.

Two paraplegic men with post-traumatic syringohydromyelia presented initially with neuropathic arthropathy of the elbow and shoulder, respectively. Both patients had sustained spinal trauma years earlier and had been lost to orthopedic and neurosurgical follow-up study. Characteristic history and physical findings were present in both patients. Conventional myelography failed to demonstrate the lesion in the first patient. The diagnosis in the second patient was confirmed by lumbar injection of low-dose metrizamide followed by immediate and delayed computerized axial tomography in the supine and lateral positions. Both patients were treated by surgical decompression and subarachnoid shunts with arrest of the neurologic deterioration. To the authors' knowledge, this is the first report of patients with post-traumatic syringohydromyelia presenting with neuropathic joints. The present case reports illustrate the need for long-term follow-up studies of patients with spine injury in specialty clinics. The use of computerized axial tomography and low-dose intrathecal metrizamide is advocated for diagnosing post-traumatic syringohydromyelia.

Adult↗
PubMedDate not supplied

Upper extremity tendon transfers in cerebral palsy: electromyographic and functional analysis.

This study was undertaken to evaluate tendon transfers in a group of children with spastic hemiplegia. Muscle grading, video recordings of function, and electromyographs were performed on 12 patients preoperatively. Postoperative electromyograms were obtained on 16 transferred tendons in eight patients as the children performed assigned tasks. Clinical evaluation demonstrated improvement in all patients at follow-up, which averaged 20 months. Four of the 16 muscles showed changes in their electrical activity postoperatively. Three muscles that fired continuously became phasic, and one muscle changed phase to match its recipient. Pre- and postoperative electromyography with video analysis provided a more complete understanding of the characteristics of tendon function with tendon transfers in cerebral palsy.

Adolescent↗