Threshold photodetachment in a repulsive potential.

We report on the first experimental observation of a new threshold behavior observed in the 5(2)G partial channel in photodetachment of K(-). It arises from the repulsive polarization interaction between the detached electron and the residual K(5(2)G) atom, which has a large negative dipole polarizability. In order to account for the observation in the K(5(2)G) channel, we have developed a semiclassical model that predicts an exponential energy dependence for the cross section.

Electron rescattering in above-threshold photodetachment of negative ions.

We present experimental and theoretical results on photodetachment of Br(-) and F(-) in a strong infrared laser field. The observed photoelectron spectra of Br(-) exhibit a high-energy plateau along the laser polarization direction, which is identified as being due to the rescattering effect. The shape and the extension of the plateau is found to be influenced by the depletion of negative ions during the interaction with the laser pulse.

Lung pathology in high-altitude pulmonary edema.

Autopsy findings in 10 cases of high-altitude pulmonary edema have been collected from published articles and personal observations. All cases were males with a mean age of 37 years (22-62). The altitude of occurrence was from 8400 to 17 500 feet.

Osteitis deformans (Paget's disease) and calcific disease of the heart valves.

The prevalence of calcific aortic valve stenosis in Paget's disease (osteitis deformans) was investigated by reviewing autopsy data of severe cases (> or = 75% involvement of > or = 3 major bones, the femur, tibia, skull, and pelvis) and moderate cases (> or = 75% involvement of only 1 or 2 major bones) of Paget's disease. Comparisons were made with normal age-matched controls. Aortic stenosis (AS) was present in 24% of 27 autopsies of severe Paget's disease compared with 3.

High altitude pulmonary edema: hemodynamic aspects.

Over 30 years ago hemodynamic studies on patients with high altitude pulmonary edema (HAPE) excluded the prior contention that the basic cause was left ventricular failure and correctly implicated the pulmonary circulation as the culprit. Physiological studies during the acute stage have revealed a normal pulmonary artery wedge pressure, marked elevation of pulmonary artery pressure, severe arterial unsaturation, and usually a low cardiac output. Pulmonary arteriolar (pre-capillary) resistance was elevated.

High-altitude pulmonary edema at a ski resort.

Medical records of 150 patients with high-altitude pulmonary edema seen over a 39-month period in a Colorado Rocky Mountain ski area at 2,928 m (9,600 ft) (mean age 34.4 years; 84% male) were reviewed. The mean time to the onset of symptoms was 3 +/- 1.

High-altitude pulmonary edema: current concepts.

High-altitude pulmonary edema (HAPE) occurs in unacclimatized individuals who are rapidly exposed to altitudes in excess of 2450 m. It is commonly seen in climbers and skiers who ascend to high altitude without previous acclimatization. Initial symptoms of dyspnea, cough, weakness, and chest tightness appear, usually within 1-3 days after arrival.

How well do older persons tolerate moderate altitude?

We studied the physiologic and clinical responses to moderate altitude in 97 older men and women (aged 59 to 83 years) over 5 days in Vail, Colorado, at an elevation of 2,500 m (8,200 ft). The incidence of acute mountain sickness was 16%, which is slightly lower than that reported for younger persons. The occurrence of symptoms of acute mountain sickness did not parallel arterial oxygen saturation or spirometric or blood pressure measurements.

Oxygen transport and cardiovascular function at extreme altitude: lessons from Operation Everest II.

Operation Everest II was designed to examine the physiological responses to gradual decompression simulating an ascent of Mt Everest (8,848 m) to an inspired PO2 of 43 mmHg. The principal studies conducted were cardiovascular, respiratory, muscular-skeletal and metabolic responses to exercise. Eight healthy males aged 21-31 years began the "ascent" and six successfully reached the "summit", where their resting arterial blood gases were PO2 = 30 mmHg and PCO2 = 11 mmHg, pH = 7.

Ten-year incidence of myocardial infarction and prognosis after infarction. Department of Veterans Affairs Cooperative Study of Coronary Artery Bypass Surgery.

Background: The 10-year incidence of myocardial infarction (fatal and nonfatal) and the prognosis after infarction were evaluated in 686 patients with stable angina who were randomly assigned to medical or surgical treatment in the Veterans Administration Cooperative Study of Coronary Artery Bypass Surgery.

Methods And Results: Myocardial infarction was defined by either new Q wave findings or clinical symptoms compatible with myocardial infarction accompanied by serum enzyme elevations with or without electrocardiographic findings. Treatment comparisons were made according to original treatment assignment; 35% of the medical cohort had bypass surgery during the 10-year follow-up period.

Quality of life after bypass surgery for unstable angina. 5-year follow-up results of a Veterans Affairs Cooperative Study.

To assess the effect of bypass surgery on outcome from unstable angina, 468 patients were randomized to medical treatment (237 patients) or surgery plus medical treatment (231 patients) and have been followed for comparison of survival, cardiac end points, and quality of life; the latter end point is discussed in the present report. Data were available at 3 and 5 years for 80% and 82% of patients in the medical group, respectively, and 77% and 80% of patients in the surgery group, respectively. At 3 months after randomization to therapy, 79.

The electrocardiogram at rest and exercise during a simulated ascent of Mt. Everest (Operation Everest II).

To evaluate the effect of extreme altitude on cardiac function in normal young men, electrocardiograms were recorded at rest and during maximal exercise at several simulated altitudes up to the equivalent of the summit of Mt. Everest (240 torr or 8,848 m). The subjects spent 40 days in a hypobaric chamber as the pressure was gradually reduced to simulate an ascent.

The sleep electrocardiogram at extreme altitudes (Operation Everest II).

To evaluate the effect of sleep at extreme altitudes upon heart rate and rhythm, continuous sleep monitoring was performed in 8 normal young men during a 40-day simulated ascent of Mt. Everest in a hypobaric chamber. Recordings were made for 1 hour before sleep, during sleep and for 1 hour after awakening in all subjects at 760 torr (sea level), in 7 subjects at 390 torr (5,490 m), in 6 at 347 torr (6,100 m) and in 4 at 282 torr (7,620 m).

Diagnostic accuracy of continuous wave Doppler echocardiography in severe aortic stenosis in the elderly.

Forty-four male patients (mean age 63.6 years) with aortic stenosis (AS) were evaluated by conventional hemodynamic methods and continuous wave (CW) Doppler echocardiography. The relationship between Doppler mean gradients and direct mean pressure gradients in all patients was significant, with an r value of 0.

Prevalence and characteristics of the aortic ejection sound in adults.

A survey of 1,950 phonocardiograms recorded over a 6-year period revealed 170 (9%) with a distinct aortic ejection sound. All patients were men with a mean age of 61 years (range 29 to 88). Associated clinical features were: aortic stenosis in 28%, history of systemic hypertension in 10%, history of rheumatic fever in 4% and none of these features in 58% of patients.

Progression of aortic stenosis in adult men. Detection by noninvasive methods.

One hundred seventy-one patients with aortic stenosis (AS) who had hemodynamic studies were evaluated by a scoring system of the seven following noninvasive variables which our laboratory had developed to estimate the severity of AS: left ventricular hypertrophy (LVH) by ECG; visible aortic valve calcification by chest x-ray examination; loudness of A2; Q to peak of systolic murmur; T-time of the carotid pulse; LV ejection time; and LVH by M-mode echocardiography. The range of the severity score is 0 to 16, and a score greater than or equal to 5 has been shown correctly to identify 93 percent of patients with severe AS (valve area less than or equal to 1.0 cm2).

Noninvasive evaluation of the severity of aortic stenosis in adults.

A noninvasive point score system for the evaluation of severity of aortic stenosis (AS) was employed in a prospective study of 153 patients (mean age 64.8 +/- 0.8 years) referred from invasive studies or for the evaluation of a systolic murmur.

Ten-year effect of medical and surgical therapy on quality of life: Veterans Administration Cooperative Study of Coronary Artery Surgery.

The long-term effect of medical vs surgical therapy on quality of life was evaluated by New York Heart Association functional classification, severity of angina and exercise performance in 427 surviving patients with stable angina at 10 years. Surgically assigned patients had significantly more improvement in functional classification, relief of angina and exercise performance at 1 and 5 years than medically assigned patients. Relative to entry, functional classification was improved in 65% of surgically treated patients at 1 year and in 51% at 5 years, compared with 45% and 40%, respectively, of medically treated patients.

Exercise tests and ventricular tachycardia.

All treadmill exercise tests done at the Palo Alto Veterans Administration Medical Center from 1973 to 1982 were reviewed to identify episodes of ventricular tachycardia (>/=3 consecutive ventricular ectopic complexes) or ventricular fibrillation occurring during or within 8 minutes of cessation of symptom-limited exercise. Of patients with a clinical diagnosis of coronary artery disease (900 tests), ventricular tachycardia occurred in 36 (4.0%) and ventricular fibrillation in 6 (0.