Biomedical subjects
W E Davis
Publications and source records attributed to W E Davis.
Basidiospore allergens: analysis of Coprinus quadrifidus spore, cap, and stalk extracts.
Atopic individuals with symptoms of respiratory allergy have been shown to have IgE-mediated reactions to spores from the basidiomycete fungi. Because our earlier studies suggested that parts of the fungus other than spores may contain allergens, the current study was performed. Extracts of Coprinus quadrifidus spores, caps, and stalks were prepared and fractionated by gel filtration column chromatography on Sephadex G-75. Analysis of column fractions of each separation by ultraviolet absorption demonstrated at least three peaks of absorbency in spore, cap, and stalk extracts. Pooled column fractions were analysed by direct radio-allergosorbent test (RAST) using pooled sera from C. quadrifidus skin-test positive subjects. Enhanced allergenic activity was present in the same portion of the column eluate for cap, spore, and stalk fractionations, corresponding to a molecular weight of approximately 10.5-25 kD. Pools with allergenic activity were used to test volunteers by skin prick and RAST. Skin test and RAST activities were similar for each of the three Coprinus extracts, with stalk being the most potent. Evidence of common allergenic epitopes was demonstrated by inhibition of spore RAST by spore, cap, and stalk extracts. These results suggest that C. quadrifidus cap and stalk extracts contain allergens similar to those in spores extract and may provide useful sources of allergen for further study.
Menière's disease. Recent advances.
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Nasal spine suspension for reduction and immobilization of mandibular fractures.
Successful treatment of mandibular fractures involves proper fracture reduction and immobilization for an adequate length of time. A simple wire fixation technique that can be used in many situations involves suspension wiring from the base of the anterior nasal spine to a pair of circummandibular wires. The technique may be used alone or adjunctively with other methods of fixation. It offers several advantages over other methods, particularly in the treatment of pediatric mandibular fractures.
The effect of sterile inflammation on skin flap survival.
Several investigations have suggested that a sterile inflammatory reaction in a skin flap enhances flap survival. A chemical peel produces a mild chemical burn, which is one form of nonbacterial inflammatory response. Some authors advocate the concomitant use of face lift and chemical peel, while others caution that the peel might jeopardize the facial flaps. To determine whether the reaction caused by a chemical peel enhances or impairs skin flap survival, a study using miniature pigs was undertaken. Survival length of flaps treated with a chemical peel was compared to that of untreated flaps. A total of 36 dorsally based random flaps were used on three miniature pigs. Six identical 14 X 4 cm flaps were designed on each side of the pigs. A chemical peel was applied to the area of 18 of the proposed flaps 2 days prior to elevation. Alternate flaps on each side of the pigs were treated. As the flaps were elevated, the tips were examined to document the inflammatory response histologically. After 14 days, the surviving length of the flaps was measured. As determined by the Wilcoxon matched-pairs signed-ranks test, there was no significant difference between the treated and untreated groups. Our study shows that a nonbacterial inflammatory response produced by a chemical peel does not improve skin flap survival, at least not in pigs.
Electrical restoration of the blink reflex in experimentally induced facial paralysis.
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The cartilage of the external ear.
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The earplug procedure.
In the measurement of hearing, a masking dilemma is a situation in which it is not possible to use masking to determine if the signal is crossing the head and activating the opposite cochlea. A nonmasking procedure, called the earplug procedure, was developed to rule out crossover for air-conducted signals in patients with a masking dilemma. In the procedure, an earplug is inserted in the suspect ear in an attempt to increase the loss in that ear. If the loss is increased significantly, then thresholds were obtained from the test ear and crossover is ruled out. If there was no significant threshold shift with the earplug, crossover is not ruled out and the uncertainty remains. Threshold shift criteria were developed for five test frequencies and for single test frequencies. The procedure correctly rules out crossover for a majority of unmaskable ears.
Deep neck abscess after tracheoesophageal puncture and insertion of a voice button prosthesis.
A deep neck abscess and cervical osteomyelitis developed in a 37-year-old laryngectomy patient 6 weeks after TE puncture and insertion of a voice button prosthesis. This complication resulted in voice prosthesis failure, multiple surgical procedures, 83 days of hospitalization while receiving parenteral antibiotics, and exposure to potentially fatal complications. Some factors contributing to this problem may include an improperly fitting prosthesis, rough insertion of the prosthesis, and altered tissue response to infection from radiation therapy and surgery.
Postauricular epidermoid cysts: treatment with electric current.
We believe the use of electric current to treat epidermoid inclusion cysts in the postauricular area is a simple, effective method that results generally in prolonged decompression of the cyst. The length of time that the fistula remains patent is unknown at present. Local control is, however, prolonged and may be permanent. Over time the induration subsides and the sac atrophies.
Development and testing of a filter system for isolation of Giardia lamblia cysts from water.
An inexpensive, practical, and reliable method for isolation of Giardia lamblia cysts from potable and environmental water has been developed from commercially available components. This system was successfully used to isolate cysts from well water associated with a family outbreak of giardiasis.
Metastasis of thyroid carcinoma to the paranasal sinuses.
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Erythromycin ototoxicity: analysis and conclusions based on 22 case reports.
Although the majority of patients receiving erythromycin experience no hearing loss, certain patients are susceptible. Erythromycin ototoxicity data were analyzed on 20 patients from 13 reports in the English language literature as well as on two patients from the University of Missouri-Columbia. Patients were classified with respect to age, sex, premorbid diagnosis, renal/hepatic function, type of erythromycin used, dosage, duration of therapy, and route of administration. The following auditory effects were considered: onset of symptoms, degree and configuration of hearing loss, and recovery of hearing. The factors which, when combined with the use of high-dose erythromycin (greater than or equal to 2 gm/day), might place patients at risk for erythromycin ototoxicity are preexisting renal or hepatic disease, age (elderly), and perhaps being female. With knowledge of the predisposing factors and auditory effects, the clinician can more easily recognize hearing loss caused by erythromycin and properly counsel referring physicians and affected patients.
Temporalis pericranial muscle flap for reconstruction of the lateral face and head.
Large ablative surgical tissue defects of the lateral face and head can pose a difficult task for the reconstructive surgeon who must choose from among a large variety of possible reparative techniques. In many situations the temporalis pericranial muscle flap offers the outstanding feature of providing a large amount of soft tissue at no direct expense of donor site skin cover. It is easily obtained and results in negligible functional loss. With care taken to preserve the neurovascular pedicle, this flap may be rotated in multiple directions and even overturned as either surface can receive surface skin closure. The amount of operative time and effort required is much less than for many of the more elaborate reconstructive flaps. Five representative cases are presented.
Subchronic toxicity in rats administered oral 8-methoxypsoralen.
Scientists at the National Toxicology Program are studying the toxicologic properties of 8-methoxypsoralen (8-MOP) with and without 320-400 nm UV (UVA). The combination of psoralen and UVA is a promising treatment for psoriasis. In this study, 8-MOP was administered to male and female Fischer 344 rats without subsequent UVA exposure for the determination of toxic effects of the psoralen alone. The drug (in corn oil) was administered by gavage 5 days/week for 90 days at doses of 0, 25, 50, 100, 200, and 400 mg/kg. The effects of toxicity were seen primarily in the 200- and 400-mg/kg dose groups, which included mortality, decreased body weight gain, and dose-related increases in liver:body ratios. On histopathology, target organ toxicity was seen in the liver, testes, and adrenals. In this study, relatively high doses of 8-MOP were tolerated in comparison to the dose of psoralen used in combination therapy clinically.
Bone-conduction threshold changes at 4,000 Hz in middle-ear surgery.
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Competencies and skills required to be an effective resource teacher.
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A technique for placement of the PORP prosthesis.
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