Field dependence and blood cholesterol: an expansion

In a pilot study of 65 newly admitted psychiatric patients the first author evaluated the relationship between cholesterol, uric acid, and field dependence. The results suggested that high uric acid and low cholesterol individuals were more field independent whereas low uric acid and high cholesterol individuals were more field dependent. However, the differences were influenced mostly by the values of cholesterol and little by the uric acid. We have now expanded the sample to 229 consecutive admissions excepting only in-patients that were alcoholics or taking medication that has effects on any of the dependent variables. Included were age, ponderal index (a ratio of height and weight), and sex. For the whole group, field dependence correlated highly with age and cholesterol but less with blood uric acid. Dividing the sample by sex the situation changed. For males field dependence did not correlate with any of the other variables. However, for the females field dependence showed a positive correlation with cholesterol and age and with cholesterol even after correcting for age. Diagnoses did not correlate with any other variables except field dependence as an analysis of variance showed an incrase of field dependence when the patients were divided into three groups: (1) schizophrenics, (2) miscellaneous (including personality disorders), and (3) affective disorders. Again, these results demonstrated no relationship of field dependence with blood uric acid.

Medical versus surgical therapy for acute coronary insufficiency. A randomized study

Forty patients with acute coronary insufficiency, including continued angina at rest and reversible ischemic electrocardiographic changes after hospitalization ("high-risk" subgroup), were randomly allotted to medical therapy or urgent surgical coronary bypass groups. In four months there were no deaths and two myocardial infarctions in 19 medical patients and one death and three myocardial infarctions in 21 surgical patients. Left ventricular ejection fraction did not change significantly in either group. The surgical patients had significantly higher functional capacities at four months as judged by lower symptomatic functional class (P less than 0.01), higher exercise angina threshold (P less than 0.001), higher pacing angina threshold (P less than 0.0001), and higher myocardial lactate extraction during pacing (P less than 0.0001). Initial medical management of patients with acute coronary insufficiency followed by elective coronary bypass in patients with continued disabling angina pectoris is a reasonable alternative to emergency bypass.

Left main coronary artery disease. Risks of angiography, importance of coexisting disease of other coronary arteries and effects of revascularization

To elucidate the determinants of the poor prognosis of patients with left main coronary artery disease and to assess the efficacy of diagnostic and therapeutic interventions the angiographic features and clinical course of 58 patients with left main coronary artery disease studied between September 1967 and June 1974 were analyzed. Eighty-three coronary arteriograms were obtained in these 58 patients using the Judkins technique; there were no immediate complications although one patient died 3 days after study. Previously cited predictors of left main coronary artery, unstable or nonexertional angina and marked S-T segment depression with exercise were found in a minority of patients; thus, the presence of the disease could not reliably be predicted before arteriographic study. Coexisting disease was found in either two or three other coronary arteries in 46 of 58 patients; only 2 patients had isolated left main coronary artery disease. Because the criteria for operability have changed in recent years, current criteria without knowledge of the treatment actually given or its outcome. The condition of 10 of 58 patients was judged inoperable in retrospect because of severe coexisting distal coronary artery disease (8 patients) or ventricular dysfunction (2 patients). Of 19 patients whose condition was judged operable in retrospect but who were treated without surgery, 9 died, 8 within 18 months; 10 have survived 12 to 83 months. Another 27 patients with a condition judged operable in retrospect had received saphenous vein bypass grafts. In this group, there were four operative and three late deaths. The severity of angina decreased in survivors treated surgically but was unchanged in survivors treated without surgery. The improvement in survival rates of surgically treated patients was not statistically significant. The data indicate that coronary arteriography can be performed at low risk with the Judkins technique even though preangiographic prediction of left main coronary artery disease is unreliable. Coexisting disease in oter major coronary arteries is an important determinant of the poor prognosis of patients with left main coronary artery disease and precludes surgery in 13 percent. Isolated left main coronary artery disease is uncommon. Surgical therapy relieves symptoms more effectively than nonsurgical therapy.

Late complications of aortic valve replacement with cloth-covered, composite-seat prostheses. A six-year appraisal

Advanced actuarial techniques are used to analyze early and late results in a closely followed series of 396 patients who received a cloth-covered, composite-seat aortic prosthesis. Late mortality and various complications are carefully assessed, and most late deaths are seen to be unrelated to the prosthesis. One hundred sixteen patients with Model 2310-2320 prostheses who received warfarin postoperatively had no thromboembolic complications in 360 patient-years of follow-up (average, 3.1 years per patient); 134 patients who had the same prosthesis but did not receive warfarin had 9 emboli per 100 patient-years (average follow-up, 1.7 years per patient; total, 228 patient-years). By comparison, in 9 years' experience with non-cloth-covered Model 1200-1260 valves, 132 patients had 4.0 emboli per 100 patient-years (average follow-up, 5.1 years; total, 673 patient-years). The safety of cloth-covered valves is clearly enhanced by concomitant use of anticoagulants; the possibility that antiplatelet drugs may suffice has not yet been demonstrated. Strut cloth wear was found at reoperation in 10 patients. The Model 2400 composite strut ("track") valve with a narrow metal track on the inner surface of each strut prevents this complication.

Subendocardial ischemia provoked by tachycardia in conscious dogs with coronary stenosis

We investigated the effect that mild coronary stenosis exerts on the ability of the coronary circulation to compensate for the increased extravascular compression that occurs in the subendocardium during tachycardia. An electromagnetic flowmeter transducer and balloon cuff occluder were implanted on the left circumflex coronary artery in seven dogs, and experiments were performed 1 week later with the dogs under sedation but conscious. Stenosis of the left circumflex artery was produced by partial inflation of the cuff occluder. We determined coronary blood flow distribution by the radioactive microsphere technique, injection 200,000 15mu spheres into the left ventricular cavity during (1) a control period, (2) stenosis of the left circumflex artery and a normal heart rate, and (3) stenosis of the left circumflex artery and tachycardia. When the heart rate was normal, the degree of stenosis used caused no change in myocardial microsphere distribution but eliminated postocclusion reactive hyperemia. Thus, reserve coronary vasodilation compensated for the stenosis. With the degree of stenosis kept constant, an increase in heart rate to 196 beats/min caused a marked transmural shift in distribution of microspheres from subendocardium into subepicardium within the region of the left ventricle supplied by the left circumflex artery. There was no significant transmural shift in the region supplied by the uninvolved left anterior descending coronary artery. Myocardial lactate extraction decreased. These results suggest that when reserve coronary vasodilation has already been utilized to compensate for coronary stenosis, the increased extravascular coronary compression from tachycardia causes subendocardial ischemia and hypoxia.

Late results following emergency saphenous vein bypass grafting for unstable angina

Fifty-five consecutive patients with intermittent resting chest pain persisting more than 24 hours after hospitalization and accompanied by ECG changes representative of ischemia were operated urgently more than one year ago. Recent cases with shorter follow-up are excluded. Twenty-eight patients had single grafts, 23 had double grafts, three had triple grafts, and one a quadruple graft. There were three operative deaths (5%) and one sudden late death (2%). There were six early Mls and three late Mls. Follow-up ranges from 12 to 52 months (mean 24 months) with nine patients followed for four years. Actuarial analysis indicates a projected survival rate of 93% three years postoperative. Twenty-three survivors are Functional Class (FC) I, 19 are FC II, and eight are FC III. Functional class could not be determined in one survivor. Thirty patients had postoperative angiography one week to 32 months postop. 35/51 grafts were patent. Only three patients had no patent grafts. There were no significant differences between mean preoperative and postoperative left ventricular end-diastolic pressures (assessed in 20 patients) or ejection fractions (assessed in ten patients). The extremely low mortality early and late postop (7%), the low incidence of Ml (16%), and the excellent functional results after extended follow-up indicate that emergency saphenous vein bypass grafting is an effective therapy for unstable angina.

Promoter-like mutation affecting HPr and enzyme I of the phosphoenolpyruvate: sugar phosphotransferase system in Salmonella typhimurium

A promoter-like mutation, ptsP160, has been identified which drastically reduces expression of the genes specifying two proteins, HPr and enzyme I, of the phosphoenolpyruvate:sugar phosphotransferase system (PTS) in Salmonella typhimurium. This mutation lies between trzA, a gene specifying susceptibility to 1,2,4-triazole, and ptsH, the structural gene for HPr. It leads to a loss of active transport of those sugars that require the PTS for entry into the cell. Pseudorevertants of strains carrying this promoter-like mutation have additional lesions very closely linked to ptsP160 by transduction analysis and are noninducible for HPr and enzyme I above a basal level. Presumably, strains carrying ptsP160 are defective in the normal induction mechanism for HPr and enzyme I, and the pseudorevertants derived from them result from second-site initiation signals within or near this promoter-like element. The induction of HPr and enzyme I above their noninduced levels apparently is not required for transport of at least one PTS sugar, methyl alpha-d-glucopyranoside, since this sugar is taken up by the pseudorevertants at the same rate as by the wild type. The existence of a promoter-like element governing the coordinate inducibility of both HPr and enzyme I suggests that ptsH and ptsI constitute an operon. Wild-type levels of a sugar-specific PTS protein, factor III, are synthesized in response to the crr(+) gene in both a ptsP160 strain and its pseudorevertants; this suggests that the crr(+) gene has its own promoter distinct from ptsP.

The prognosis of patients with coronary artery disease after coronary bypass operations. Time-related progress of 532 patients with disabling angina pectoris

The clinical progress of 532 patients who were treated for ischemic heart disease by coronary bypass grafting during a five-year period was studied. All patients had at least 50% luminal narrowing of one or more major coronary arteries determined by preoperative coronary arteriography and relatively stable and disabling (New York Heart Association Functional Class III and IV) angina pectoris. During the total observation period there were 35 deaths: 18 early and 17 late. The over-all 4-year survival rate by life-table methods was 89%, and it differed among patients with one-vessel involvement (96%), two-vessel involvement (89%), and three-vessel involvement (84%), but not significantly so. The patency rate of bypass grafts determined in 191 patients at a mean time of six months postoperatively was 76%. Functional class I and II status was 93% during the first year and was 75% during the fourth year after operation in observed survivors.