Jaw deformity caused by juvenile rheumatoid arthritis and its correction

An underdeveloped mandible and resulting micrognathia and malocclusion may occur in some children with juvenile rheumatoid arthritis. Combined orthodontic and surgical procedures can now greatly improve esthetics and function in such children. We describe corrective treatment and followup of 7 patients.     

Hemodynamic and metabolic response after abrupt uithdrawal of long-term propranolol

Because the mechanism of adverse reactions to abrupt withdrawal of propranolol in patients with coronary disease is an enigma, we studied the effect of cessation of propranolol on beta receptor reactivity to catecholamine stimulation. Heart rate and maximum rate of rise of left ventricular pressur (dP/dt max) during isoproterenol infusions and plasma free fatty acids (FFAs) after epinephrine infusions were measured in six conscious dogs before, during and after four weeks of oral propranolol (40 mg p.o. q8h). Rises in heart rate, dP/dt max and FFAs were blocked during propanolol administration. Twenty-four hours after withdrawal from propranolol, heart rate and dP/dt max responses remained significantly attenuated, although FFA responses were at premedication levels. The 72-hour, 96-hour and one week postmedication responses did not differ from premedication values. Thus, partial beta blockade of the heart was still present at 24 hours and no evidence of heightened beta receptor sensitivity was detected on repeated study one week after withdrawal from a long-term, high dose propranolol regimen.     

Glutamine synthetase of Mycobacterium tuberculosis: extracellular release and characterization of its enzymatic activity.

We have investigated the activity and extracellular release of glutamine synthetase [L-glutamate:ammonia ligase (ADP-forming), EC 6.3.1.2] of Mycobacterium tuberculosis. The purified, homogeneous M. tuberculosis glutamine synthetase appears to consist of 12 most likely identical subunits of M(r) 58,000, arranged in two superimpose hexagons. In the catalysis of L-glutamine, the enzyme has an apparent Km for L-glutamate of approximately 3 mM at the pH optimum of 7.5. M. tuberculosis releases a large proportion (approximately 30%) of its total measurable enzyme activity into the culture medium, a feature that is highly specific for pathogenic mycobacteria. Immunogold electron microscopy revealed that M. tuberculosis also releases the enzyme into its phagosome in infected human monocytes. Two potentially important roles for glutamine synthase in the pathogenesis of M. tuberculosis infection are (i) the synthesis of L-glutamine, a major component of the cell wall of pathogenic but not nonpathogenic mycobacteria, and (ii) the modulation of the ammonia level in the M. tuberculosis phagosome, which may in turn influence phagosomal pH and phagosomelysosome fusion.     

Metabolic evidence of inadequate coronary blood flow during closed-chest resuscitation in dogs

Closed-chest cardiopulmonary resuscitation (CPR) produces only small pressure differences across the coronary circulation and relatively little coronary blood flow in dogs with ventricular fibrillation. To determine whether coronary flow during experimental resuscitation is sufficient to maintain aerobic myocardial metabolism, we measured left ventricular adenosine triphosphate (ATP) and lactate concentrations before and immediately after a 20 min period of CPR in six fibrillating dogs. The mean aortic-right atrial pressure difference generated during CPR averaged 5.4 +/- 2.6 mmHg (SEM) and 3.2 +/- 2.6 mmHg at the beginning and end of the 20 min period, respectively. Left ventricular myocardial blood flow (measured with radioactive microspheres) averaged 16.7 +/- 5.7% of prearrest values during the first 10 min of CPR, and 8.5 +/- 4.8% of prearrest values during the second 10 min of CPR. Biopsies after CPR contained less ATP (3.3 +/- 0.1 vs 4.7 +/- 0.5 nmol.mg-1, p less than 0.05) and more than seven times more lactate (14.7 +/- 3.1 vs 1.9 +/- 0.2 nmol.mg-1, p less than 0.01) than control biopsies. We conclude that coronary blood flow during CPR is inadequate relative to myocardial oxygen demands during ventricular fibrillation in dogs. The techniques developed in this study provide a potential means of assessing the effects of experimental interventions on myocardial oxygenation during CPR.     

Serum Zinc and Taste Acuity in Tel-Aviv Patients with Inflammatory Bowel Disease

Serum zinc levels and taste acuity were determined in patients with Crohn's disease, those with ulcerative colitis, and normal controls. All serum zinc values were within the normal range but significantly lower in the Crohn's disease patients as compared with controls. The taste threshold for salt was significantly impaired in patients with inflammatory bowel disease. These findings were less than expected and may be explained by the relatively high zinc intake normal for the Tel-Aviv population and relate indirectly to the high intake of refined carbohydrate that occurs in Crohn's disease patients.