Assignment of the Raman spectra of some deuterated-BEDT-TTF superconductors.

We present the room-temperature Raman spectra of both the protonated and deuterated forms of kappa-(BEDT-TTF)2Cu[N(CN)2]Br, kappa-(BEDT-TTF)2Cu(NCS)2 and beta-(BEDT-TTF)2I3. Along with data for the neutral BEDT-TTF molecule these spectra are used to assign the many features in the spectra of the deuterated compounds.

Computer analysis of oxygen consumption and minute ventilation for the detection of the lactate threshold.

A group of 15 normal subjects performed a maximal-exercise test on a treadmill. Arterial lactate measurements were related to oxygen consumption (VO2) in an exponential fashion (individual correlation coefficients ranged from 0.9 to 0.99). In the same subjects, minute ventilation (VE) was related to VO2 in an exponential fashion (individual correlation coefficients ranged from 0.98 to 1). There was a close correlation (r = 0.97, p less than 0.001) between the slope of the log of lactate versus VO2 and the slope of the log of VE versus VO2. A computer program for predicting the VO2 corresponding to the accumulation of arterial lactate above the resting normal value (1.3 mM), defined as the lactate threshold, is described. The program is based on the slopes of the exponential relationship between lactate and VO2 and between VE and VO2 derived in the normal subjects. The program analyses 30-second values of VO2 and VE. In 28 subjects, the reproducibility of the lactate threshold prediction was evaluated during two exercise tests 1-7 days apart. The mean predicted VO2 at the lactate threshold was 18.6 +/- 7 ml/(kg.min) during test 1 and during test 2 it was 17.9 +/- 7.3 ml/(kg.min); r = 0.91, p less than 0.001. The corresponding values for maximal VO2 were 30.4 +/- 13 ml/(kg.min) and 31 +/- 13 ml/(kg.min); r = 0.99, p less than 0.001. It is concluded that this program offers a reproducible method of determining the lactate threshold during exercise testing employing a frequently used clinical protocol.

Comparison of nitroglycerin patches and nifedipine.

Fifteen patients with stable angina participated in a 12-week crossover study to evaluate the efficacy of nifedipine and nitroglycerin patches. There was an initial 2-week drug washout period followed by a 2-week control period when patients received no other antianginal treatment other than sublingual nitroglycerin for relief of angina episodes. At the end of the 2-week control period, exercise performance was assessed with treadmill exercise testing and measurement of oxygen consumption during the final third of the dosing interval. Myocardial perfusion was assessed using thallium scintigraphy with the injection of thallium at 85% of the maximum oxygen consumption. Patients were then randomized to nifedipine or nitroglycerin patches, and the dosage was titrated at weekly intervals according to symptomatic response. The final dose was received for at least 2 weeks. After 4 weeks, patients received the alternate medication. Maximal exercise testing and thallium scintigraphy were repeated after each drug period. Both nifedipine (mean dose, 70 mg/day) and nitroglycerin patches (mean dose, 16 cm/day) significantly reduced the frequency of angina and the consumption of sublingual nitroglycerin. Nifedipine decreased the reversible thallium defect score (49 +/- 29 vs. 28 +/- 26 U, p less than 0.01). Both drugs reduced electrocardiographic evidence of myocardial ischemia at submaximal exercise. Maximal oxygen consumption was not significantly increased by either drug when the test was done during the latter part of the dosing interval. The clinical implications of this study are that the dosage of nifedipine and nitrate patches, based on symptomatic criteria of angina frequency reduction, may not result in objective improvement in exercise performance.

Patterns of oxygen consumption during exercise testing in peripheral vascular disease.

Exercise testing on a treadmill was performed in 15 patients with peripheral vascular disease to determine the pattern of oxygen consumption during exercise. A plateau in the oxygen consumption over the final 90 s of exercise was used as a criterion for maximal effort and only 4 out of 15 (27%) obtained a plateau of oxygen consumption compared to 20 out of 26 (77%) normal subjects (chi 2 7.9, p less than 0.005). These findings may account for the limited value of exercise testing in detecting coronary artery disease in patients with peripheral vascular disease.

Comparison of acute hemodynamic effects of nitroglycerin versus diltiazem and combined acute effects of both drugs in angina pectoris.

Fifteen patients with exertional angina underwent hemodynamic monitoring and measurement of cardiac output during a control treadmill exercise test. They were then randomized to receive sustained-release nitroglycerin, 13 mg (group I) or placebo (group II). Repeat exercise testing revealed that in group I, both maximal oxygen consumption and cardiac output increased significantly. In group II neither maximal oxygen consumption nor cardiac output increased significantly. All patients then received diltiazem, 60 mg, and repeat testing was carried out 1 hour later. In group I maximal oxygen consumption and cardiac output were higher than control, but were no higher than after nitroglycerin. In group II, maximal oxygen consumption increased significantly, but the increase in cardiac output was not significant. Thus, sustained-release nitroglycerin, 13 mg, or diltiazem, 60 mg, both improve exercise performance, but the combination does not improve exercise performance to an extent greater than either drug alone.

Computerized detection of the lactate threshold in coronary artery disease.

A computer program for identifying oxygen consumption at the lactate threshold was evaluated by expired gas analysis during treadmill exercise testing in 15 patients with prior myocardial infarction. There was a strong correlation (r = 0.85, p less than 0.001) between computer-identified oxygen consumption (14.1 +/- 4.6 ml/kg/min) and the oxygen consumption (14.6 +/- 4.8 ml/kg/min) corresponding to an increase of arterial lactate level to above the normal value at rest (1.3 mM). The computer program was superior to previously described visual methods for identifying the ventilatory threshold.

Effects of the limiting symptom on the achievement of maximal oxygen consumption in patients with coronary artery disease.

This study was conducted to determine if the limiting symptom in patients with coronary artery disease (CAD) influenced the pattern of oxygen consumption (VO2) over the final 90 seconds of a maximal exercise test. The pattern was classified according to the presence or absence of a plateau. Twenty-six normal persons and 55 patients with CAD were studied. They rated the severity of fatigue, dyspnea and angina at end exercise using the Borg scale and designated which symptom was the limiting factor. A plateau of VO2 over the final 90 seconds of exercise was observed in 77% of normal subjects and patients with CAD. Eighty percent of patients limited by angina achieved a plateau. In normal subjects and patients with CAD, peak VO2 was more reproducible than the pattern of VO2 over the final 90 seconds of exercise. There were no differences in the cardiac responses to exercise at maximal effort between patients who achieved a plateau of VO2 and those who did not. These results indicate that the limiting symptom of exercise, even angina pectoris, does not influence the ability to exercise maximally. Therefore, the peak value of VO2 during symptom-limited treadmill exercise is a valid measure of maximal cardiovascular capacity irrespective of the limiting symptom or the pattern of VO2 in the final 90 seconds of exercise.

Prevalence of pneumonias caused by Legionella species among patients on whom autopsies were performed.

We wanted to determine the prevalence of pneumonias caused by Legionella species among patients on whom autopsies were performed in two medical centers in St Louis from January 1976 to June 1981. We screened formaldehyde-fixed deparaffinized lung tissue sections with microscopic evidence of pneumonia from 97 patients with use of the direct immunofluorescence antibody technique with a multivalent antilegionella conjugate containing antibodies to Legionella pneumophila serogroups 1 through 4 plus other Legionella species. One patient (1%) had disseminated L pneumophila serogroup 1 infection. We conclude that the prevalence of pneumonias caused by L pneumophila (serogroups 1 through 4), Legionella micdadei, Legionella bozemanii, Legionella dumoffii, or Legionella gormanii is low in the patients studied.

Nomogram for estimating normal liver weights.

A nomogram was constructed by which the normal weight of a patient's liver can be estimated from the patient's height and weight.