Serologic survey for canine coronavirus in wolves from Alaska.

Wolves (Canis lupus) were captured in three areas of Interior Alaska (USA). Four hundred twenty-five sera were tested for evidence of exposure to canine coronavirus by means of an indirect fluorescent antibody procedure. Serum antibody prevalence averaged 70% (167/240) during the spring collection period and 25% (46/185) during the autumn collection period. Prevalence was 0% (0/42) in the autumn pup cohort (age 4-5 mo), and 60% (58/97) in the spring pup cohort (age 9-10 mo). Prevalence was lowest in the Eastern Interior study area. A statistical model indicates that prevalence increased slightly each year in all three study areas. These results indicate that transmission occurs primarily during the winter months, antibody decay is quite rapid, and reexposure during the summer is rare.

Prevalence of bone marrow signal abnormalities observed in the temporomandibular joint using magnetic resonance imaging.

PURPOSE: The purpose of this investigation was to determine the prevalence of bone marrow signal abnormalities in patients referred for temporomandibular joint (TMJ) magnetic resonance imaging (MRI). This investigation was done because of prior studies suggesting that condylar marrow signal abnormalities indicate avascular necrosis. SUBJECTS AND METHODS: Retrospective review was done of 449 consecutive TMJ MR examinations in 415 patients from 1991 to 1994. Examinations were obtained with a surface coil at 1.5 T with routine T1, T2, and T2* images. Condylar marrow signal abnormalities were reviewed and classified into either a bone marrow edema pattern (hypointense T1, hyperintense T2) or a sclerosis pattern (hypointense T1 and hypointense T2). Patients with typical findings of osteoarthritis were excluded from the sclerosis category. RESULTS: Condylar marrow signal abnormalities were present in 37 patients (9%). Twenty-six patients (6%) had the edema pattern, 14 patients (3%) had the sclerosis pattern, and 3 patients had both. Two patients with the edema pattern had a history of surgery; five patients with the sclerosis pattern had a history of surgery. The only follow-up MRIs obtained in the 37 patients were on one patient with edema at 8 months and on one patient with sclerosis at 10 months. MRI demonstrated a stable appearance of these patterns. CONCLUSION: It was concluded that condylar marrow signal abnormalities are not rare in patients referred for TMJ MRI. The clinical significance of the changes is uncertain.

Skeletal muscle infarction in diabetes: MR findings.

We present a case of multiple skeletal muscle infarctions in the lower extremities of a diabetic. Magnetic resonance findings and differential diagnosis are discussed.

Hemodynamic progression of aortic stenosis in adults assessed by Doppler echocardiography.

Doppler echocardiography was used to follow the hemodynamic severity of aortic stenosis. First, the reproducibility of repeat recordings (mean interval 28 +/- 36 days) of aortic jet velocity, made by two independent observers, was tested in 38 adults with aortic stenosis and unchanged clinical status. The two recordings of maximal velocity correlated well (r = 0.96, y = 0.88x + 0.46m/s, SEE = 0.21 m/s) with a mean coefficient of variation of 3.2%. Repeat recording of left ventricular outflow tract velocity by two independent observers in 10 other patients with aortic stenosis also correlated well (r = 0.94, y = 1.06x + 0.0 m/s, SEE = 0.06 m/s) with a mean coefficient of variation of 4.6%. Next, Doppler echocardiography was used to study 42 patients with aortic stenosis (mean age 66 years) over a follow-up interval of 6 to 43 months (mean 20). Maximal aortic jet velocity increased by 0.36 m/s per year (range -0.3 to +1.0 m/s per year). Mean transaortic pressure gradient changed by -7 to +23 (mean 8) mm Hg/year. Aortic valve area by the continuity equation (n = 25) decreased by 0 to 0.5 cm2/year (mean decrease 0.1 cm2/year). Some patients had a worsening of stenosis (decrease in valve area) even though they had no change or a decrease in pressure gradient, because of concurrent decreases in transaortic volume flow. Twenty-one patients (50%) developed new or progressive symptoms of aortic stenosis necessitating valve replacement.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental validation of Doppler echocardiographic measurement of volume flow through the stenotic aortic valve.

In aortic stenosis, evaluation of aortic valve area by the continuity equation assumes that the volume of flow through the stenotic valve can be measured accurately in the left ventricular outflow tract. To test the accuracy of Doppler volume-flow measurement proximal to a stenotic valve, we developed an open-chest canine model in which the native leaflets were sutured together to create variable degrees of acute aortic stenosis. Left ventricular and aortic pressures were measured with micromanometer-tipped catheters. Volume flow was controlled and varied by directing systemic venous return through a calibrated roller pump and back to the right atrium. Because transaortic volume flow will not equal roller pump output when there is coexisting aortic insufficiency (present in 67% of studies), transaortic flow was measured by electromagnetic flowmeter with the flow probe placed around the proximal descending thoracic aorta, just beyond the ligated arch vessels. In 12 adult, mongrel dogs (mean weight, 25 kg), the mean transaortic pressure gradient ranged from 2 to 74 mm Hg, and transaortic volume flow ranged from 0.9 to 3.2 l/min. In four dogs, electromagnetic flow that was measured distal to the valve was accurate compared with volume flow determined by timed collection of total aortic flow into a graduated cylinder (n = 24, r = 0.97, electromagnetic flow = 0.87 Direct +0.13 l/min). In eight subsequent dogs, electromagnetic flow was compared with transaortic cardiac output measured by Doppler echocardiography in the left ventricular outflow tract as circular cross-sectional area [pi(D/2)2] x left ventricular outflow tract velocity-time integral x heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Simplification of the Doppler continuity equation for calculating stenotic aortic valve area.

Determination of aortic valve area by the continuity equation is feasible and accurate but requires planimetry. Because the ratio of maximum velocities in the left ventricular outflow tract (LVOT) to aortic jet is quite similar to the ratio of velocity-time integrals at these sites, the continuity equation can be simplified by substituting maximum velocities for velocity-time integrals. Agreement with invasively determined aortic valve areas is similar with the conventional and simplified forms of the continuity equation. However, substitution of the average or sex-specific LVOT diameter for measured LVOT diameter in individual patients leads to less accurate aortic valve area determination. We conclude that simplification of the continuity equation, with measured LVOT diameter and maximum velocity and aortic jet maximum velocity, allows noninvasive calculation of the aortic valve area in a way that is simple and accurate.

Consultant utilization by family physicians in a university hospital practice.

All inpatient consultations obtained by family physicians at a university hospital were monitored for 2 1/2 years to determine the number and types of consultations obtained. Overall, 1,017 consultations were obtained on 2,155 patients (0.47 consultations per patient). The consultation rate, however, gradually decreased from 0.56 consultations per patient at the beginning of the study to 0.36 consultations per patient at the end of the study, probably corresponding to cost-containment pressures placed on physicians by increasing involvement with prepaid health care plans. The specialties most frequently consulted were cardiology, gastroenterology, neurology, and pulmonary medicine, which together accounted for more than one third of all consultations obtained.

Comparison and assessment of drugs used to immobilize Alaskan gray wolves (Canis lupus) and wolverines (Gulo gulo) from a helicopter.

One hundred and three Alaskan gray wolves and 12 wolverines were immobilized in the Nelchina and upper Susitna River Basins of southcentral Alaska between March 1977 and May 1981. Sixty-five wolves were immobilized with a mixture of phencyclidine HCl and promazine HCl (PP/HCl); 38 wolves were immobilized with etorphine HCl (EHCl) and 12 wolverines were immobilized with EHCl or with a mixture of EHCl and xylazine HCl (XHCl). Phencyclidine HCl is no longer commercially available and an assessment of etorphine HCl as a replacement drug was made. Etorphine HCl dosage of 2.5 mg/wolf proved to be a suitable replacement for PP/HCl for immobilizing wolves while 0.7 mg EHCl with 50 mg XHCl appeared suitable for wolverines.