Epidemiologic factors involved in perinatal lamb mortality on four range sheep operations.

Four shed-lambing operations in western Colorado were monitored during the 1984 spring lambing season to determine the causes and rates of perinatal lamb mortality. The number of lambing ewes per flock ranged from 513 to 1,712, and lambing percentages ranged from 131 to 180%. Overall perinatal lamb mortality ranged from 8.2 to 12.2%. Most lamb deaths occurred during parturition or within 24 hours after parturition. More than 85% of all lamb deaths were in lambs born to ewes having 2 or more lambs. The leading causes of lamb death were starvation, dystocia, stillbirth (unknown cause), and infectious diseases. A wheel model was used to categorize factors causing lamb deaths into 4 groups: physical, social, host, and biological, and to present data on perinatal lamb mortality in a simple visual model. In all flocks, social and biological factors resulted in most of the lamb deaths. On the basis of our findings, we suggest that interventions designed to improve ewe-lamb bonding and to reduce infectious agents and the incidence of prolonged parturition may reduce lamb mortality.

Malignant nerve sheath tumors of the head and neck: a combined experience from two university hospitals.

Malignant schwannoma is an aggressive neoplasm whose cell of origin and histologic characteristics remain controversial. Despite advances in diagnostic techniques, the natural history of this tumor remains uncertain. The charts of all patients with malignant schwannoma who were treated at the UCLA Center for the Health Sciences and the University of Iowa Hospital and Clinics were retrospectively reviewed. Sixteen patients received surgery and radiotherapy in combination or as sole therapy. Irrespective of treatment modality, prognosis was poor with an overall survival of 15%. Recent advances in imaging and histologic techniques that assist in establishing the diagnosis and delineating tumor location are discussed. In addition, the literature pertaining to malignant schwannoma of the head and neck is reviewed.

Plasma cell tumors of the head and neck.

This communication discusses seven cases of plasma cell tumors isolated to the head and neck and reviews the pertinent literature. Five of the cases presented were located in the nasal passages and the paranasal sinuses, one in the temporal bone and one in the mandible. Because these neoplasms may signal the presence of multiple myeloma, full evaluation is required to exclude disseminated disease. Thereafter, the treatment of choice is high-dose radiotherapy with life-long follow-up. Radiographs and paraprotein levels may be used to assess tumor control or dissemination. Should new lytic lesions occur, or an elevation in paraprotein levels be noted, consideration should be given to further irradiation or systemic chemotherapy. Surgery is reserved exclusively for diagnostic purposes or when severe functional disability intervenes.

Comparison of speech recognition-in-noise and subjective communication assessment.

A comparison was made between speech recognition performance in conditions of quiet and babble (Speech Perception in Noise Test) and items from a self-assessment scale concerned with communication ability in quiet and noise (Understanding Speech section of Hearing Performance Inventory). Performance on both the speech recognition and self-assessment tests differentiated between normal listeners and individuals with mild-to-moderate sensorineural hearing loss. For the hearing-impaired group, correlations between speech recognition scores and ratings on the self-assessment items were poor, suggesting that performance measured with these tests have only a weak relationship.

A steroid constituent from Solanum abutiloides.

A steroidal aglycone, isonuatigenin, has been isolated from the hydrolysate of unripe fruits of Solanum abutiloides. The acetylation of isonuatigenin in weak acid has been studied.