Abomasal emptying defect of sheep may be an acquired form of dysautonomia.

Abomasal emptying defect (AED) is a disease syndrome that primarily affects Suffolk sheep and is characterized by distension and impaction of the abomasum. No histologic lesion has been consistently associated with this condition. There is no known etiology. In this study, nine cases of AED were identified by necropsy, including three rams and six ewes between 2 and 6 years of age. Four of the cases occurred sporadically, and five ewes were submitted on the same day from a single flock. Histologic examination of celiacomesenteric ganglia from six of the affected sheep revealed scattered chromatolytic or necrotic neurons, without inflammation. Chromatolytic neurons were observed more frequently in AED-affected sheep than in seven healthy Suffolk sheep (P < 0.08, weak statistical support). Neuronal necrosis was not observed in any of the healthy sheep. Lineage records of the flock that suffered an outbreak were incompatible with the possibility of a simple inheritance pattern for this disease; furthermore, the very occurrence of AED in outbreak form is inconsistent with transmission solely by inheritance. Only one of the six tested sheep showed concurrent immunohistochemical evidence of scrapie. The lesion pattern in celiacomesenteric ganglia is suggestive of a neurotoxicosis. Neuronal lesions of AED resemble dysautonomic diseases of humans and other animals.

Inflight cabin ozone aboard long duration C-5 airlift missions: a historical issue revisited.

BACKGROUND: Past research has shown that U.S. Air Force C-5 aircrews have been occasionally exposed to ambient, stratospheric ozone concentrations in excess of Federal Aviation Administration (FAA) ceiling and time-weighted average (TWA) standards. Although strategies such as steering around meteorological areas of high ozone concentrations or outfitting the C-5 with ventilation system modifications were recommended by past investigators, review has shown that such changes were not adopted. Informal interviews with current C-5 aircrews indicate mucosal dryness and irritation are routinely encountered during long duration flights. Such symptoms could be due to low humidity or perhaps, ozone-induced irritation. With the advent of miniaturized, highly accurate, electronic air quality monitoring equipment, a repeat study of cabin ozone was believed to be warranted to better clarify exposure risk and to look for other possible explanations for the encountered symptoms. METHODS: A portable, electronic air quality monitor was used to monitor breathing zone cabin air during 47 h of flight. Ozone, carbon dioxide, carbon monoxide, temperature, and relative humidity were recorded for the duration. Ozone levels were corrected for altitude using a calibration curve derived by earlier, unpublished hypobaric chamber work. RESULTS: Ozone levels were not found to exceed the FAA ceiling limit. Two flights had 3-h time-weighted average values that minimally exceeded FAA standards. Carbon dioxide and carbon monoxide levels were well below health effect threshold. Relative humidity reached a nadir of 3% and could well have explained symptoms of mucosal irritation. CONCLUSIONS: Current evidence suggests that C-5 aircrews are exposed to relatively low concentrations of ozone. Review of the literature regarding observed short-term and long-term toxicity to low dose ozone exposure would indicate that no further operational or aircraft design action is required.

Effects of combining methylphenidate and a classroom token system in modifying hyperactive behavior.

The combined effects of methylphenidate and a token reinforcement program in controlling a classroom behavior of 16 hyperactive, institutionalized retarded youngsters was investigated. A within-subject, placebo-controlled, double-blind design was employed. The results indicated that the behavior-modification procedures in the presence of placebo medication produced significant increases in work-oriented and related decreased in disruptive behavior. Few effects from the addition of active medication to the treatment program were found on any of the dependent measures. The findings suggest behavior modification to be a viable alternative to drug therapy for hyperactivity in retarded persons.