Biomedical subjects
Publications and source records attributed to T M Davidson.
This article reports a case of digital intraarticular envenomation from a T. flavomaculatus mcgregori pit viper resulting in severe joint damage. Bites by these snakes are rare in the U.S.A. since this species is only found in collections and zoos. Intraarticular envenomations from crotalids are rare and may result in joint destruction.
We have used 35S-labelled RNA probes to detect TNF cytokine gene expression in nasal mucosa derived from patients with perennial rhinitis. As mast cells comprise a minor component of the total cell population in nasal mucosa, additional methods are needed to determine whether mast cells contribute to the cytokine mRNA detected by in situ hybridization. We have combined in situ hybridization with alternate methods to detect mast cells (tryptase immunostaining or toluidine blue staining) and determined that in situ hybridization coupled with tryptase immunostaining provides optimal methods to detect mast cell cytokine gene expression in tissue sections. Using in situ hybridization and tryptase immunostaining, we demonstrate that mast cells in nasal mucosa can express TNF mRNA. However, the number of tryptase-, TNF+ cells (1.99 +/- 1.59 cells/mm2) exceeded the number of tryptase+, TNF+ mast cells (0.09 +/- cells/mm2). Mast cells thus comprised a subpopulation of the total number of TNF mRNA positive cells in nasal mucosa.
IL-1 and tumor necrosis factor (TNF) are cytokines that share many overlapping functions, including induction of expression of the vascular cell adhesion molecule (VCAM) by endothelial cells. However, because most studies of cytokine induction of adhesion molecules have used human umbilical vein endothelial cells (HUVECs) and not microvascular endothelial cells, the functional significance of such observations to sites of allergic inflammation, such as the nasal mucosa, are at present unknown. We have therefore used nasal mucosa to compare the functional response of these microvascular endothelial cells with HUVECs. HUVECs or nasal mucosal explants were stimulated in vitro with varying concentrations of IL-1 or TNF for 0 to 48 hours, and VCAM mRNA and protein expression were determined by means of immunostaining and in situ hybridization. TNF and IL-1 were equivalent in their ability to induce VCAM mRNA and protein expression by HUVECs. In contrast, TNF was significantly more potent than IL-1 in inducing VCAM mRNA and protein expression by nasal mucosal microvascular endothelial cells. The recovery of significant amounts of IL-1 after incubation of recombinant IL-1 with nasal mucosa, as well as the ability of IL-1 to induce intercellular adhesion molecular expression by nasal mucosa, suggests that neither degradation of IL-1 nor downregulation of IL-1 receptors in nasal mucosa is likely to explain the inability of IL-1 to induce VCAM expression by nasal mucosa. These studies suggest that microvascular endothelial cells in the nasal mucosa differ functionally from HUVECs and that TNF may be more important than IL-1 in induction of VCAM expression in the nasal mucosa.
The prevalence of parosmia and phantosmia among 363 chemosensory and nasal/sinus patients was studied, as was the accuracy with which our clinical questionnaire could assess these dysfunctions. We then investigated whether patients with parosmia or phantosmia, matched for odor intensity, perform poorer on odor identification than do patients with no dysosmia. More than 40% of the study group evidenced either parosmia (18.7%) and/or phantosmia (25.6%), a finding that suggests that more attention should be paid by the medical practitioner in addressing qualitative olfactory dysfunction. Furthermore, it appears that assessment of these dysfunctions may aid in differential diagnosis, and that questionnaires can be used with reasonable validity irrespective of the patient's age. Finally, the results imply that parosmia may be reflected in a discrepancy between odor identification and detection.
Mambas are venomous African snakes that are capable of inflicting fatal envenomation. The mambas (genus Dendrosaspis) are members of the family Elapidae [1]. Four species of mamba inhabit equatorial and southern Africa. Without medical treatment, mamba bites are frequently fatal. First aid treatment includes lymphatic retardation with immobilization and pressure wrap. Medical management requires the intravenous administration of mamba-specific antivenin.
Injury patterns in alpine skiing have changed over time as ski, boot, binding, and slope-grooming technologies have evolved. We retrospectively examined injury patterns in alpine skiers over a 9-year period at the Mammoth and June mountains (California) ski area. A total of 24,340 injuries were reported for the 9 seasons studied, and total lift tickets sold numbered 9,201,486. The overall injury rate was 2.6 injuries per 1,000 skier days and increased slowly over the period studied. The knee was the most frequently injured area at 35% of all injuries. Increasing trends (P < .05) were noted for the rates of lower extremity injuries (37%) and knee injuries (45%). A decreasing trend was noted for the rate of lacerations (31% decrease). Slight increases were noted in upper extremity and axial injury rates. Skiing injuries continue to be a worrisome recreational problem despite improvements in ski equipment and slope-grooming techniques. The increasing trend in lower extremity, particularly knee, injury rates highlights the need for continued skier education and equipment innovation.
Snowboarding is a rapidly growing winter sport. Its unorthodox maneuvers and young participants raise many safety concerns. We examined injury patterns in recreational snowboarders, comparing these patterns with those found in alpine skiers. Snowboarding and skiing injury patterns differed significantly (P < .05) for the following categories: 49% of injured snowboarders were beginners versus 18% of skiers. Snowboarders were more likely to suffer wrist (19% versus 2%) and ankle (16% versus 6%) injuries, but less likely to sustain knee (17% versus 39%) or thumb (2% versus 4%) injuries than skiers. For snowboarders, wrist injuries were most common in beginners (30%), knee injuries in low intermediates (28%), ankle injuries in intermediates (17%), and shoulder or clavicle injuries in advanced snowboarders (14%). Most snowboarders (90%) wore soft-shelled boots, 73% of lower extremity injuries occurred to the lead-foot side, and 73% of wrist injuries occurred during backward falls; 67% of knee injuries occurred during forward falls. Of all injuries, 8% occurred while loading onto or unloading from a ski lift. The sport of snowboarding brings with it a different set of injuries from those seen in alpine skiing. The data focus attention on improvements such as wrist guards or splints, releasable front-foot bindings, and better instruction for beginner snowboarders to improve the safety of this sport. Finally, the data confirm that snowboarders and skiers may be safely combined on the same slopes.
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Human encounters with cobras in Africa and Asia are common with substantial mortality and primarily respiratory paralysis in untreated cases. First aid includes maintaining calm, placing a lymphatic retardant on the bitten extremity, and transportation to a medical facility. Medical management is antivenin. Physiologic monitoring and the ability to manage the compromised airway are important.
Patients who have lost the sense of smell usually come to a doctor on their own, reporting loss of the sense of taste. Inflammation (often due to allergy), viral infection, and head trauma are common causes of olfactory disturbance. History taking may provide clues to these and other problems (eg, toxin exposure, congenital dysosmia). Workup should not begin until a standardized test has been given that established impairment of the sense of smell. The only truly reversible cause is inflammation, which is confirmed when smell returns after a course of corticosteroid. Sinus computed tomography is necessary to view the olfactory cleft; lack of obstruction indicates that smell impairment is nonreversible. Patients deserve an explanation for their disorder and a prognosis. If restoration of their sense of smell is unlikely, patients should be cautioned to take steps to ensure safety in regard to such dangers as gas leaks, smoke, and spoiled foods.
In 90% of children, otitis media with effusion resolves within 3 months. When it persists longer, it is considered chronic. Initial treatment of chronic otitis media with effusion is repeated courses of antibiotics, and a short course of steroids may be appropriate. Use of antihistamines and decongestants has not been shown to be efficacious, although they may be beneficial when inhalant allergies contribute to eustachian tube dysfunction. Persistent effusion leads to conductive hearing loss, which may have a significant impact on language, speech, and intellectual development. Thus, surgical therapy consisting of insertion of tympanostomy tubes and, in selected cases, adenoidectomy is indicated to improve hearing and prevent long-term sequelae.
Chronic sinusitis is one of the more common chronic diseases in the United States. Over the past decade endoscopic sinus surgery (ESS) has become more common than ethmoidectomy and inferior meatal nasoantral windows. A review of the recent ESS literature, including 10 large series with a total of 1,713 patients, shows a 91% improvement rate. Subjectively, 63% of patients reported a very good result, 28% a good result, and 9% an unsatisfactory result. Twelve percent of patients required revision surgery. Major complications occurred in 1.6% of patients. Objective evaluation of the effectiveness of ESS, through the use of sinus CT, endoscopy, rhinometry, and olfactory testing, has shown mixed results.
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We present a patient complaining of severe proptosis and diplopia, who had a large ethmoid mucocele. The patient was treated with endoscopic surgical drainage. He had complete resolution of all symptoms. There is no evidence of recurrence at six months follow-up.
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