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Twenty-four Wistar rats were anesthetized and 200 degrees C heat was applied for 4 minutes to each mandibular left first molar. Eight of these rats were then killed at 2, 8, and 14 weeks. The subject and control teeth were radiographed and compared. They were then prepared for histologic evaluation and scored for levels of inflammation in both the pulpal and periradicular tissues. Furcal, interproximal, and apical radiographic changes were found at all three time intervals. These changes involved progressively larger percentages of teeth at 8 and 14 weeks. Histologically, complete necrosis and/or abscess formation were found in the coronal portions of all experimental pulps. With time, inflammatory changes increased in intensity and progressed through the radicular pulps, resulting in necrosis or calcific changes and, finally, inflammatory changes in the periradicular areas. The pathosis created by the application of heat was devoid of microorganisms as evaluated by the Brown and Brenn stain.

The acute hemodynamic responses to intravenous infusion of piroximone (MDL 19,205), a nonglycoside, noncatecholamine agent with positive inotropic activity in vitro, were compared with those of intravenous dobutamine and sodium nitroprusside, respectively, in 2 groups of patients with New York Heart Association class III or IV symptoms. Each drug was titrated to optimal dosage (dobutamine, 12.5 +/- 3.9 micrograms/kg/min; nitroprusside, 2.5 +/- 0.6 micrograms/kg/min; piroximone 1.4 +/- 0.6 mg/kg) and simultaneous hemodynamic and scintigraphic values were measured. In group 1, the increase in cardiac index was slightly greater with piroximone than with dobutamine (from 1.6 +/- 0.5 to 2.7 +/- 0.6 vs 2.4 +/- 0.6 liters/min/m2, p less than 0.025) and only piroximone significantly decreased left ventricular (LV) filling pressure (from 29 +/- 7 to 22 +/- 8 mm Hg, p less than 0.05). Both agents increased heart rate and systolic blood pressure. In group 2, cardiac index increased similarly with nitroprusside and piroximone (1.5 +/- 0.6 to 2.6 +/- 0.8 and 1.6 +/- 0.5 to 2.6 +/- 0.5 liters/min/m2, difference not significant), whereas LV filling pressure decreased slightly less with piroximone (29 +/- 7 to 24 +/- 10 vs 30 +/- 7 to 20 +/- 11 mm Hg, difference not significant). Only nitroprusside reduced mean arterial pressure (88 +/- 13 to 72 +/- 12 mm Hg, p less than 0.001 between drugs). In group 1, systolic blood pressure to end-systolic volume ratio increased in 9 of 10 patients taking both piroximone and dobutamine, whereas in group 2, this ratio increased in 7 of 8 patients taking piroximone and declined in 7 of 8 taking nitroprusside.(ABSTRACT TRUNCATED AT 250 WORDS)

To determine whether significant spontaneous hemodynamic changes occur without therapeutic intervention, 15 patients with stable heart failure underwent right-sided cardiac catheterization and were observed without active treatment during an 8-hour period. Significant changes that mimic those seen during treatment with vasodilating medications were found. Increases were seen in heart rate (minimum 82 +/- 19 beats/min, maximum 88 +/- 18 beats/min, p less than 0.05) and cardiac index (minimum 2.14 +/- 0.45 liters/min/m2, maximum 2.42 +/- 0.79 liters/min/m2, p less than 0.05). Decreases were observed in pulmonary artery wedge pressure (maximum 24 +/- 7 mm Hg, minimum 21 +/- 7 mm Hg, p less than 0.05) and systemic vascular resistance (maximum 1,600 +/- 280 dynes-s-cm5, minimum 1,390 +/- 310 dynes-s-cm-5, p less than 0.05). Except for the decrease in pulmonary artery wedge pressure, all hemodynamic changes appeared to be related to eating. In addition, a statistically significant postprandial decrease in mean blood pressure (before meal 85 +/- 12 mm Hg, after meal 78 +/- 11 mm Hg, p less than 0.05) was seen. These data reinforce the need for caution in interpreting small hemodynamic changes, even if statistically significant, and they indicate the desirability of including placebo groups or phases in drug studies and of performing hemodynamic measurements the postabsorptive state.

To assess the variability of rest and exercise radionuclide ventriculography in patients with aortic regurgitation (AR), 22 patients in stable condition with chronic AR underwent radionuclide ventriculography at rest and during exercise for measurement of left ventricular volumes and ejection fraction (EF) on 2 occasions 3 months apart. For the group, there were no significant differences between the findings of the 2 studies except for a slightly lower exercise end-systolic volume on the second study. The inter-study differences and variabilities (expressed as the standard deviation of differences) for rest and exercise EF and change in EF were 0 +/- 0.04, +0.02 +/- 0.05 and +0.01 +/- 0.05, respectively. Thus, although mean differences were minor, considerable individual variability occurred, the magnitude of which was similar to that reported for other patient populations. In 3 patients who had an initial normal response to exercise (increase in EF greater than or equal to 0.05), the response became abnormal and in 2 who initially had an abnormal response, the response normalized. This variability must be considered in clinical decision-making or in research study design for patients with chronic AR.

An analysis of the clinical, radiographic, histologic and follow-up data on 249 cases of lesions of periodontal membrane origin is presented. Such lesions may be cementoid, osteoid, mixed (cemento-osteoid) or fibrous. These tumors may be single or multiple and usually behave in a benign fashion. Occasionally they may act in an aggressive manner and attain giant size, although none metastasize. The benign fibro-osseous lesions of periodontal membrane origin are more prevalent in the jaws than fibro-osseous lesions of medullary bone origin. The use of polarized light was most helpful in distinguishing mature cementoid lesions from tumors with mature lamellar bone; the former have finer lines of parallel birefringence. Fibrous dysplasia has often been misused as a diagnostic term and was found not to be prevalent as a fibro-osseous jaw lesion. Fibrous dysplasia has its own particular histologic features, and the immature "woven" bone within the lesion polarizes in a random birefringent pattern.