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Biomedical subjects

G W Mitchell

Publications and source records attributed to G W Mitchell.

At least 37 records · Page 2Linked to original sources
PubMed1996

Leukoencephalopathy associated with cobalamin deficiency.

Patients with cobalamin deficiency may experience cognitive impairment or neuropsychiatric symptoms. Although abnormalities of central myelin are the presumed cause of these manifestations, there is a paucity of reports of white matter lesions as shown on neuroimaging studies, and the effects of cobalamin replacement on these lesions are not known. We report a man with subacute cognitive impairment associated with cobalamin deficiency and remarkable confluent white matter abnormalities on MRI, confirmed by biopsy. With cobalamin replacement, both his cognitive deficits and imaging abnormalities partially resolved. This case indicates that leukoencephalopathy, in the absence of anemia or myelopathy, should be added to the spectrum of disorders associated with cobalamin deficiency. Early detection and treatment may be associated with a greater potential for recovery.

Aged↗
PubMed1994

The effect of test chart design and human factors on visual performance with night vision goggles.

In an effort to increase flight safety, it is imperative to learn as much as possible about the man-goggle interrelationship. This study was undertaken to see if type of goggle or other covariates might affect visual acuity (VA). We tested the VA of 103 aircrew with both the AN/PVS-5 and Aviator's Night Vision Imaging System (ANVIS) goggles using a Snellen vision testing chart and the new Night Vision Goggle (NVG) Resolution (Grid Type) Chart. Average VA's using ANVIS (Snellen = 20/38, Grid = 20/45) were significantly better (p < 0.01) than VA's using AN/PVS-5 (Snellen = 20/54, Grid = 20/58). Snellen VA's were better on average than Grid VA's (p < 0.001). Neither age, gender, nor NVG experience affected average VA at the 0.05 level. Average VA was significantly better (p < 0.05) for non-spectacle wearers using ANVIS goggles and for non-smokers using AN/PVS-5 goggles. Visual acuity is better with ANVIS than with AN/PVS-5 goggles, and may be affected somewhat by wearing spectacles, and by smoking.

Adult↗
PubMed1994

Otologic devices.

The use of artificial devices to enhance audition is increasingly common. Although most complications of implanted devices, such as cochlear stimulators, occur in the immediate postoperative period, many later difficulties may come to the attention of the emergency medicine practitioner. This article reviews the common and uncommon complications of hearing aids, ossicular replacements, and implants. Advancements in this area will make such problems even more common in the future.

Cochlear Implants↗
PubMed1991

Class II antigen expression in peripheral neuropathies.

The expression of class II antigen was studied in sural nerve biopsies from patients with peripheral neuropathies. These included patients with chronic demyelinating polyradiculoneuropathy (CIDP), non-immune mediated neuropathies of diverse etiologies and controls without evidence of neuropathy. The major finding in CIDP was a marked increase in class II expression on Schwann cells. Endoneurial Schwann cell staining to the same degree as in CIDP was seen in diabetic symmetric proximal motor neuropathy, neuropathies associated with monoclonal gammopathies and hereditary sensory and autonomic neuropathy type 1. In the control nerves and the other non-immune mediated neuropathies class II expression was mainly restricted to endothelial and perineurial cells. Increased endoneurial expression of class II antigen was found to correlate with elevated cerebrospinal fluid (CSF) protein levels but not with other clinical variables or demyelination as defined by electrophysiologic criteria or teased fiber analysis. The increased expression of class II antigen on Schwann cells may be indicative of a breakdown in immunological tolerance but should not be used as a diagnostic marker for dysimmune neuropathies due to overlap with non-immune mediated neuropathies.

Adult↗
PubMed1991

Rapid onset of severe heat illness: a case report.

Aviators flying extended periods in hot environments are known to be at risk for heat-related illness. The risk when wearing chemical individual protective equipment (IPE) is increased even at relatively warm temperatures and light workloads. In this paper, we report the physiological responses of an aviator who had been flying a UH-1H helicopter up to 6 h/d clothed in full IPE on 6 consecutive days prior to the sudden onset of heat illness. His performance during the study was normal, and no clear physiological derangements were noted prior to his symptoms. The rapid evolution of his symptoms after voicing no complaints provides a graphic illustration of the difficult predictability and initial central nervous system effects of this condition.

Adult↗
PubMed1990

Viral hepatitis.

Viral hepatitis is the most common serious contagious disease caused by viruses that attack the liver. Approximately 70,000 cases are reported to the Centers for Disease Control each year, representing only a fraction of U.S. cases. There are five types of viral hepatitis currently known: Hepatitis A--formerly called infectious hepatitis; Hepatitis B--formerly called serum hepatitis, and the most serious form; Hepatitis C--formerly called non-A, non-B hepatitis; Hepatitis D--formerly called delta hepatitis; Hepatitis E--formerly called enteric or epidemic non-A, non-B hepatitis. The following Open Forum, prepared by leading EMS experts, explores the differences among the types of hepatitis, signs and symptoms, and EMS implications.

Allied Health Personnel↗
PubMed1989

Menstrual pattern change 1 year after sterilization: results of a controlled, prospective study.

To determine if female sterilization is associated with adverse menstrual change, we compared prospectively collected menstrual data from women who underwent sterilization via bipolar cauterization, banding, and Pomeroy ligation with data from women whose husbands obtained a vasectomy and from women who were not planning sterilization. At first-year follow-up, sterilization via banding with Falope rings was not associated with adverse change. After excluding initially abnormal cases: (1) cauterization women were bleeding more heavily than all other groups excepting Pomeroy; (2) cauterization and Pomeroy women experienced more dysmenorrhea than women not planning sterilization; and (3) more cauterization and Pomeroy women (collapsed samples) developed abnormal length cycles than did the two control groups. There were no group differences regarding development of beneficial/neutral change (e.g., decreased dysmenorrhea). However, cauterization and Pomeroy groups experienced a significantly higher average number of adverse changes than did the other groups and were at significantly greater risk of developing one or more adverse changes than were women not planning sterilization. The only pattern of association among adverse menstrual changes occurred significantly more often in the cauterization and next in the Pomeroy groups.

Adult↗
PubMed1989

A survey of U.S. Army aeromedical equipment.

Medical equipment is necessary to support patients requiring air transportation, but it may not be compatible with the aviation environment. Aircraft systems may cause errors in the functioning of medical equipment, or that equipment may interfere with the aircraft. Medical equipment has been tested, primarily for fixed wing aircraft, to military standards by the U.S. Air Force. This study reports 1986 and 1987 surveys which document the use of such equipment on U.S. Army medical evacuation aircraft and compares items in current use to the U.S. Air Force's test results. Of the 115 different nonissue items reported in use, 32 have been formally evaluated, and 9 of those were judged unacceptable for use on aircraft. Only two items reported in the survey were tested inflight in helicopters. The remaining 83 items have not been tested. Helicopters have unique requirements, and the U.S. Army has begun a program to evaluate medical equipment for helicopter use.

Aerospace Medicine↗
PubMed1988

Early diagnosis of basilar artery occlusion using magnetic resonance imaging.

Three patients with a clinical diagnosis of pontine infarction probably due to basilar artery occlusion were studied with magnetic resonance imaging within 24 hours after onset or latest progression of symptoms. The earliest changes on magnetic resonance images were an absence of signal void in the basilar artery suggestive of severe reduction of blood flow or occlusion (flow-void phenomena). The presumed basilar artery thrombosis was best demonstrated as a linear structure isointense or hyperintense with the brainstem in the pontine cistern on T1-weighted parasagittal images and as either absence of flow-void phenomena or higher signal intensity at various levels corresponding to the course of the basilar artery on the axial T2-weighted images. Brainstem parenchymal changes characteristic of infarction were not obvious for at least 12 hours after onset or 90 minutes after latest progression of symptoms and were best shown by both axial and coronal T2-weighted images. Recognition of these magnetic resonance imaging findings may allow earlier diagnosis and treatment of acute ischemia in the vertebrobasilar system.

Adult↗
PubMed1987

Response to immunosuppressive therapy in patients with hereditary motor and sensory neuropathy and associated dysimmune neuromuscular disorders.

We encountered 2 patients with hereditary motor and sensory neuropathy (HMSN) type I who had marked weakness developing during several months superimposed on chronic peroneal muscular atrophy. Further studies disclosed a chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) in one patient and CIDP associated with polymyositis in the other. Both patients responded to prednisone and azathioprine with substantial improvement. Patients with HMSN who develop rapid progression of weakness should be evaluated for superimposed, potentially treatable dysimmune neuromuscular disorders.

Adult↗
PubMed1984

Residual tumor following radiotherapy for locally advanced carcinomas of the uterine cervix. Prognostic significance.

Over a five-year period from 1977 to 1982, 120 patients with locally advanced carcinomas of the uterine cervix were surgically staged by lymphadenectomy and laparotomy. Radiotherapy was then administered according to the pelvic extent of disease, and all patients underwent extrafascial total hysterectomy with adnexectomy at ten weeks after completing radiation therapy. The presence or absence of residual tumor in the hysterectomy specimen appeared to be an important prognostic factor in treatment success or failure. Patients with no residual tumor were found to have an excellent prognosis. Those with residual tumor clear of the resection margins were at risk for distant metastases. Only one survivor was noted in the group of patients in whom the margins of resection were involved with tumor, nearly all of these patients dying from local recurrences. Major operative morbidity in the series was minimal, and consisted of a single ureterovaginal fistula, which required urinary diversion.

Adenocarcinoma↗
PubMed1983

Ovarian carcinoma: management of stress in patients and physicians.

A discussion of the management of ovarian cancer invariably involves the problems of death and dying faced by the patient, her family, and her physician. This paper attempts to deal with the general fears, anxieties, and problems of terminality, and also places attention on specific issues involved in living with the ongoing disease and its treatments. Focus is on the effects of the disease on the woman's self-image, on her family and relationships, on life outside the hospital, and on her relationship with her attending physician. Specific problems relating to the periods of (1) diagnosis, (2) operative management and treatment, and (3) terminality are discussed. Understanding the psychosocial realities of the patient provides the physician with added insights into methods to assist the patient in adaptation and coping with this ultimately fatal disease.

Adult↗
PubMed1983

Perforation of the ileum as a complication of suprapubic catheterization.

Although suprapubic catheterization is a useful technique in managing the postoperative patient who requires prolonged urinary drainage, the potential exists for iatrogenic damage to the abdominal contents. Two cases of perforation of the distal ileum occurring during catheter placement after vaginal procedures are presented. Such complications may be kept at a minimum by adequate bladder distention, careful bladder palpation, placement of the patient in the Trendelenburg position before filling the bladder, and catheter insertion before closure of the surgical incision.

Adult↗