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Biomedical subjects

D C Musch

Publications and source records attributed to D C Musch.

84 records · Page 5Linked to original sources
PubMed1985

Exposure of tantalum mesh orbital implants.

This retrospective study of 195 enucleations with tantalum mesh implants reviews the role of demographic, preoperative, and operative factors in subsequent implant exposure or extrusion. Fourteen implants (7.2%) became exposed, two of which subsequently extruded. Significant associations were found between implant exposure and history of prior orbital infection, and suturing of the inferior oblique to the lateral rectus muscle. The average age at enucleation was 20.4 years for those whose implant became exposed, which was significantly less than the average age of 38.7 years for those without exposure of the implant. No association was found between implant exposure and gender, preoperative diagnosis, proptosis, chemosis, sharp trauma to the orbit, orbital fracture, previous orbital surgery, implant size, closing of posterior Tenon's capsule, or muscles sutured to the implant. Because of the high exposure rate, it is recommended that the use of tantalum mesh implants be discontinued.

Adult↗
PubMed1985

Orbital compliance in Graves' eye disease.

Thirty-three patients with Graves' eye disease (GED) and 68 normal subjects had their orbital compliance measured by determining the force generated on retropulsing the eye and also estimated on digital retropulsion, and their eye position determined with an exophthalmometer. Patients with compressive optic neuropathy showed significantly higher mean forward force on retropulsion than other Graves' eye disease patients or normal subjects, supporting the theory that the tissue is compressed in these orbits. There is a suggestion that orbital compliance testing of a GED patient without compressive optic neuropathy may be of value in predicting the risk of the patient developing compressive optic neuropathy. There is no association between the force on ocular retropulsion and the exophthalmometer reading. The digital estimation of the resistance to retropulsion did not reliably suggest the measured forces.

Compliance↗
PubMed1985

Some factors influencing interobserver variation in classifying simple pneumoconiosis.

Three experienced physician readers assessed the chest radiographs of 743 men from a coal mining community in West Virginia for the signs of simple pneumoconiosis, using the ILO U/C 1971 Classification of Radiographs of the Pneumoconioses. The number of films categorised by each reader as showing evidence of simple pneumoconiosis varied from 63 (8.5%) to 114 (15.3%) of the 743 films classified. The effect of film quality and obesity on interobserver agreement was assessed by use of kappa-type analytic procedures for measuring agreement on categorical data. Poor film quality and obesity both affected agreement adversely. Poor quality films were disproportionately frequent in obese individuals, as defined by the Quetelet index. On control of film quality by stratification, the effect of obesity on interobserver profusion agreement was no longer evident.

Coal Mining↗
PubMed1984

Treatment of blepharospasm with botulinum toxin. A preliminary report.

The effects of botulinum A toxin injections for the treatment of facial spasm were analyzed for 22 patients. Sixteen patients had unoperated on essential blepharospasm, three had essential blepharospasm with residual spasm following previous surgical treatment, and three had unoperated on hemifacial spasm. Treatment was effective for most patients, but transient, with the mean interval of relief of spasm after the first injections being ten weeks. The injection of botulinum toxin reduced the maximum lid force by about 10%. While side effects were common, they were generally mild and well tolerated. No cumulative effect of botulinum toxin was evident in those receiving three series of injections. There is no significant difference in either the interval free of spasm or the rate of lid-force recovery following any of three sequential injections of increasing doses of botulinum toxin.

Adult↗
PubMed1983

Demographic and predisposing factors in corneal ulceration.

We identified 224 patients hospitalized with corneal ulcerations at the University of Michigan Hospitals, Ann Arbor, between May 1975 and September 1981, and performed a chart review on a random sample of these cases. Bimodality in the patients' age distribution was attributed to nonsurgical ocular trauma in the younger group, and predisposing keratitis, surgical trauma, bullous keratopathy, and entropion in the older group. Bacterial and postherpetic causes accounted for 52 (52%) of the sampled cases. Pseudomonas aeruginosa and Staphylococcus aureus were the major isolates. Important predisposing factors included nonsurgical and surgical trauma, herpetic keratitis, contact lens wear, corticosteroid therapy, and bullous keratopathy. Both age and visual acuity on admission had prognostic implications for improvement in visual acuity after treatment.

Adult↗
PubMed1983

Reliability of ophthalmic diagnoses in an epidemiologic survey.

In the Nepal Blindness Survey, 39,887 people in 105 sites were examined by 10 ophthalmologists from Nepal and four other countries during 1981. Ophthalmic protocols were pretested on approximately 3000 subjects; however, interobserver variability was inevitable. To quantify the amount of variability and assess the reliability of important ophthalmic measures, a study of interobserver agreement was conducted. Five ophthalmologists, randomly assigned to one of two examining stations in a single survey site, carried out 529 pairs of examinations. Eighty demographic and ophthalmic variables were assessed at each station. In 62 of 80 (77.5%) measures, observer agreement exceeded 90%. Since pathologic findings were rare, however, chance agreement alone could yield misleadingly high per cent agreement; therefore, the kappa statistic was used for assessing comparative reliability of ophthalmic measures. There were 74 measures for which kappa could be computed and ranked by strength of agreement: 20 (27%) showed excellent agreement (kappa = 0.75-1.00), 39 (53%) showed fair to good agreement (kappa = 0.40-0.74), and 15 (20%) showed poor agreement (kappa less than 0.40). In general, measures dealing with blindness prevalence or causes of blindness showed substantial or almost perfect agreement, while polychotomous descriptions of rare clinical signs demonstrated less agreement.

Adolescent↗
PubMed1982

Occupational exposure to carbon black: a particulate sampling study.

In order to determine the particulate exposure levels within carbon black production plants, a sampling survey involving workers from seven carbon black producers was initiated in late 1979. A total of 1,951 acceptable samples (1,564 total dust and 387 respirable dust) were collected from closed-face filter cassettes worn by carbon black workers performing normal work operations. A one-centimeter cyclone separator was employed for respirable dust sampling. Overall sampling distributions of the time-weighted average values generated from the survey were best described by the log-normal distribution. Characterization of the particulate exposures to workers is provided for the various areas of employment and specific jobs within these areas. Summary geometric mean time-weighted average values by area of employment and by job category are well within the carbon black permissible exposure limit (PEL) of 3.5 mg/m3. Identification of those job categories subject to relatively higher particulate exposures, and quantification of these exposures, is essential to the effective industrial hygiene monitoring and control of worker exposures.

Carbon↗
PubMedDate not supplied

An application of kappa-type analyses to interobserver variation in classifying chest radiographs for pneumoconiosis.

We investigated interobserver variation between three physician readers in the independent classification of chest radiographs from 1771 taconite workers for pneumoconiosis. We analysed variation with a general methodology for the analysis of categorical data, and quantified interobserver agreement in terms of kappa-type statistics. The results revealed considerable variation in the profusion of opacities reported by each observer. This was especially so for the earliest radiographic changes, but variation also occurred with the small number of films in the series showing category 2 pneumoconiosis or over. Variation in the classification of profusion of small opacities was greater in films of poor quality, and also increased with the length of time between taking and reading the film (film age). We could not account for the effect of film age by controlling for film quality, as subjectively assessed by the readers.

Epidemiologic Methods↗
PubMedDate not supplied

Visual field results after vitreous surgery in a case series of patients with open-angle glaucoma.

BACKGROUND AND OBJECTIVE: Visual field loss is a complication of vitrectomy and a concern for patients with glaucoma. Our objective was to determine whether vitrectomy is associated with new field defects in patients with glaucoma. PATIENTS AND METHODS: This retrospective case series involved 7 eyes of 7 patients, who had open-angle glaucoma and underwent vitrectomy for macular hole (2) or epiretinal membrane (5). RESULTS: Acuity improved by at least two lines in 5 eyes. Visual fields showed a change in mean deviation following vitrectomy (mean difference -1.50 dB, P=0.0006, paired Student's t-test). One eye had confirmed progression of a pre-existing visual field defect, but no new defects were apparent in the other eyes. Transient intraocular pressure rises requiring therapy occurred in 3 eyes. One eye developed macular edema, but no other operative complications occurred. CONCLUSIONS: The results of our small case series suggest that vitrectomy may be an acceptable intervention in eyes with glaucoma and co-existing macular problems.

Aged↗
PubMedDate not supplied

Epidermal growth factor and insulin in use in corneal preservation: study design and objectives of a multi-center trial.

This study determines whether endothelial survival after penetrating keratoplasty is improved by adding the mitogens, human epidermal growth factor (hEGF), and human insulin to a chondroitin-sulfate-based corneal storage medium. It is a multicenter, prospective, double-masked, randomized trial that compares endothelial survival of human corneal transplants using donor corneas that have been stored in one of two media: DexSol (CSM with 1% dextran) or DexSol containing recombinant hEGF and human insulin. This article describes the study design and entry characteristics of the 105 recipient pairs. Each donor pair of corneas is transplanted on the same day into recipients who are matched by diagnosis and procedure. Clinical parameters assessed on day 1, week 1, and 3, 6 and 12 months postoperatively include graft clarity, epithelial integrity, corneal thickness, visual acuity, and intraocular pressure. Postoperative endothelial survival for both groups will be determined by morphometric analysis of endothelial cell images before storage and at 3, 6, and 12 months postoperatively. Such analysis will also identify differences in polymegathism (cell size) or pleomorphism (cell shape).

Adult↗