Experimental results of cancellous autografts and frozen allografts transplanted into the canine frontal sinus.

Autograft and frozen allograft cancellous bone were each placed into one of the canine frontal sinus cavities of eight animals and analyzed by radiographic and histologic methods after one year. Complete and equal bony obliteration was demonstrated. Thus no advantage was seen in using an autograft over a frozen allograft in obliterating the frontal sinus cavity.

Upper digestive tract burns caused by Denalan denture cleanser powder.

Denture cleansers are ubiquitous compounds frequently found in the household. Severe oral cavity burns were clinically observed in a two-year-old female who accidentally ingested a denture cleanser powder, Denalan. Experimental studies were carried out to investigate the caustic, chemical and histopathological properties of this compound. Denalan was found to be a powerful alkali agent which caused severe upper digestive tract burns.

Glutaraldehyde-fixed bovine pericardium for right ventricular outflow enlargement.

Right ventricular outflow tract enlargement using glutaraldehyde-fixed bovine pericardium was evaluated experimentally using the pig model. Twelve piglets (8-16 kg) underwent closure of surgically created, longitudinal right ventriculotomies using premeasured, round, bovine pericardial patches. Half of the animals had pulmonary artery banding to increase right sided pressures. The animals were studied an average of 5.1 months following surgery. Cardiac catheterization was performed on eight animals. Pressure measurements revealed no gradient across any outflow patch, and angiography showed no stenosis or dilatation. There was marked right ventricular hypertension in the banded animals. The hearts from all twelve animals were examined grossly and microscopically. There was endothelialization of all patches with no aneurysm formation. Measurements revealed that most patches had become oval shaped. There was no difference in patch size changes between banded and non-banded animals. The patches showed no significant size change in the longitudinal plane (average from 20.8 mm to 20.3 mm, 6.3% change); however, there was a significant decrease in the transverse size (20.8 mm to 17.3 mm, 16.0%) (p less than 0.001). The change in patch size was probably due to reshaping to conform to the longitudinal ventriculotomy and caused no narrowing. In this study, glutaraldehyde-fixed bovine pericardium appeared to be satisfactory for right ventricular outflow enlargement. Favorable qualities include ease of handling, hemostasis, and no aneurysm formation.

Proton irradiation and endometriosis.

Female rhesus monkeys given single total-body exposures of protons of varying energies developed endometriosis at a frequency significantly higher than that of nonirradiated animals of the same age. The minimum latency period was 7 years after exposure. The doses and energies of the radiation received were within the range that could be received by an aircrew member in near-earth orbit during a random solar flare event, leading to the conclusion that endometriosis should be a consideration in assessing the risk of delayed radiation effects in female crewmembers.

Effects of verbal and visual cues on performance of a complex ballistic task.

An ecological approach to the study of feedback for learning sport tasks involves understanding how both augmented and inherent feedback interact. Literature on sport psychology suggests that athletes differ from nonathletes in characteristics that relate to learning styles and use of feedback. The purpose of this study was to examine differences in learning style between college female athletes and non-athletes on a complex ballistic task (dart throwing) differentiated by verbal and visual cues. 19 college women athletes and 19 nonathletes participated under four different conditions: visual cued/verbal cued, visual cued/verbal noncued, visual noncued/verbal cued, visual noncued/verbal noncued. Analysis of variance indicated that athletes were superior to nonathletes under the visual cued/verbal noncued condition. Both groups showed a linear trend for improvement but athletes were significantly better on the last trial.

The role of potassium ion in muscle glycogenolysis and glycolysis.

We have presented evidence that in an in vitro system, glycogenolysis and glycolysis function normally at potassium levels far below those observed in muscle cell water of severely deficient dogs. We suggest that a functional impairment of glycogenolysis or glycolysis is unlikely to be a mechanism by which potassium deficiency leads to rhabdomyolysis.

Long-term inhalation toxicity of hydrazine.

Year-long intermittent exposures of rats, mice, hamsters, and dogs to hydrazine were conducted using concentrations of 0.05, 0.25, 1.0, and 5.0 ppm. Rats were held 18 months postexposure; hamsters, 1 year postexposure; mice, 15 months postexposure; and dogs, 38 months postexposure. Male and female rats exhibited dose-dependent incidences of benign nasal adenomatous polyps and smaller numbers of malignant nasal epithelial tumors after 1 year of exposure to hydrazine and 18 months postexposure holding. Nasal tumors were often associated with chronic irritation and were most frequent in male rats, with an incidence of greater than 50% in the highest exposure group. Hamsters exposed to 0.25-ppm and higher concentrations showed pathologic changes characteristic of degenerative disease, including amyloidosis. After exposure to 0.5 ppm hydrazine, hamsters developed a 10% incidence of benign nasal polyps compared to 0.5% in controls. Small numbers of colon neoplasms and thyroid parafollicular cell adenomas were found in hamsters, but only in the highest concentrations tested. Lung adenomas appeared to be marginally increased in mice exposed to 1.0 ppm hydrazine, the highest concentration tested in this species. No consistent clinical or pathological effects were seen in dogs during or after exposure to hydrazine at any concentration. Using amyloidosis as a criterion, a no-effect level was not achieved in hamsters. In rats, there appeared to be a marginal production of nasal tumors at 0.05 ppm, while mice showed no effects at 0.25 ppm. This study has demonstrated that the nasal respiratory epithelia of rats and hamsters are the most sensitive tissues to the tumorigenic action of hydrazine following inhalation exposures. This is similar to the reaction of rats to formaldehyde, another highly reactive water-soluble compound.