Vitamin A homeostasis and diabetes mellitus.

Recent studies have shown that plasma concentrations of vitamin A (retinol) and its carrier proteins, retinol-binding protein (RBP), and transthyretin (TTR), are decreased in human subjects with insulin-dependent (IDDM) but not with noninsulin dependent diabetes mellitus (NIDDM). Rats made diabetic with streptozotocin (STZ) have also been shown to have reduced levels of plasma vitamin A while its hepatic concentrations elevate. The circulatory vitamin A levels remained low while its hepatic concentrations were further elevated following supplementation of the vitamin. The reduced circulatory status of vitamin A in diabetic animals was not caused by its impaired intestinal absorption. Further experimental studies have pointed to the fact that IDDM is associated with a deficiency of vitamin A, which is secondary to an impaired transport mechanism of this vitamin from its hepatic storage to the target site, such as retina of the eyes. The diabetes-associated changes in vitamin A metabolism were reserved to normal by insulin treatment. The underlying cause for decreased metabolic availability in uncontrolled diabetes, is not clearly understood. It appears that the increased hepatic store of vitamin A is attributed to a decreased availability of its carrier proteins. Subnormal vitamin A status in poorly controlled diabetic subjects may not respond to vitamin A supplementation, rather it may increase its load in the liver leading to hepatoxicity. These results clearly suggest that there is need for further research identifying the importance of vitamin A in diabetes mellitus.

Vitamin A (retinol) status of first nation adults with non-insulin-dependent diabetes mellitus.

OBJECTIVE: Poorly controlled insulin-dependent diabetes mellitus (IDDM) has been reported to be associated with an impaired metabolic availability of vitamin A. The purpose of this study was to examine vitamin A status in a select group with non-insulin dependent diabetes mellitus (NIDDM). METHODS: Participants included 106 (male, female, > 40 years) Plains Cree adults residing in central Alberta, with NIDDM (n = 59) and non-diabetic controls (n = 47). Non-fasting plasma samples were collected and concentrations of retinol, zinc, alpha-tocopherol, total protein, albumin, retinol binding protein (RBP), transthyretin (TTR), cholesterol, triglycerides, glucose, insulin, and fructosamine were determined. Multiple linear regression was used to identify predictors of plasma RBP concentration. Three repeated 24-hour recalls and a food frequency questionnaire were used to determine vitamin A intakes. RESULTS: Diabetic subjects had similar intake and plasma concentration of vitamin A compared to controls. Factors such as alpha-tocopherol, zinc, total protein, albumin, and TTR, which are known to influence vitamin A metabolism, also remained unaffected in subjects with diabetes. Plasma levels of vitamin A carrier protein (RBP), however, were elevated in diabetic subjects, possibly as a result of hyperinsulinemia. The subjects with diabetes had many characteristics of the insulin resistant syndrome, including central obesity, hypertension, and hypertriglyceridemia. Poor metabolic control, based on plasma glucose, was a significant predictor of RBP concentration in diabetic subjects. CONCLUSIONS: The plasma concentration of RBP was elevated in diabetic subjects and was associated with normal circulatory availability of retinol. The subjects with NIDDM, characterized by insulin resistance without insulin deficiency, thus, appear to be associated with normal vitamin A status.

Thrombolytic therapy for right heart lesions.

Thrombolytic agents are accepted therapy for occlusion of coronary and peripheral arteries as well as for venous thromboses. Although the treatment of left heart prosthetic valve thrombosis has been evaluated, there are limited data showing the benefit of thrombolysis of right heart clots. Two patients with past histories of multiple cardiac operations were given fibrinolytic therapy for thrombosis involving right heart structures. The first patient had thrombosis of a prosthetic pulmonary valve. The second patient was a type IB tricuspid atresia who developed a Fontan duct stenosis and right atrial clot. Thrombolytic therapy may provide a safe alternative to surgical intervention for thrombosis of right heart structures and, even when incompletely effective, may provide additional time to prepare patients for surgical correction and possible protection against distal embolization during surgical intervention.

Functional impact of remodeling during healing after non-Q wave versus Q wave anterior myocardial infarction in the dog.

OBJECTIVES: This study was undertaken to compare changes in left ventricular remodeling and function during healing after a first anterior non-Q wave versus a Q wave myocardial infarction in the dog. BACKGROUND: Whether ventricular remodeling is more severe after anterior Q wave than after anterior non-Q wave infarction has not been studied systematically. METHODS: Serial remodeling and functional variables (two-dimensional echocardiography), electrocardiography and hemodynamic data were recorded over 6 weeks in 58 instrumented dogs subjected to left anterior descending coronary artery ligation or ligation plus collateral obliteration. Postmortem topography and transmurality (by planimetry) and infarct collagen (hydroxyproline) were measured at 6 weeks. RESULTS: At 6 weeks, infarct collagen was similarly increased in both groups, but the Q wave group had greater infarct size (7.2% vs. 4.5%, p less than 0.025) and greater transmurality (88% vs. 58%, p less than 0.001), higher left atrial pressures, more infarct expansion (expansion index 2.62 vs. 2.31, p less than 0.001), more thinning (thinning ratio 0.62 vs. 0.72, p less than 0.001), greater cavity dilation (diastolic volume 88 vs. 72 ml, p less than 0.001), more regional bulging in the short-axis view (depth 4.9 vs. 1.9 mm, p less than 0.001), more regional asynergy (18% vs. 7%, p less than 0.001), lower global ejection fraction (40% vs. 48%, p less than 0.001), more endocardial and epicardial bulging in the long-axis view and greater incidence of aneurysm (82% vs. 36%, p less than 0.005), left ventricular thrombus (64% vs. 0%, p less than 0.0005) and ventricular arrhythmias. Echocardiograms obtained during a 6-week period indicated that left ventricular topographic deterioration and dysfunction were present in the earliest postinfarction study at 2 days in both groups but were more frequent in the Q wave group. Regional myocardial blood flow (24 dogs) was lower in the Q wave than in the non-Q wave group. Scanning electron microscopy (10 dogs) revealed preservation of the epicardial collagen matrix in the non-Q wave but not the Q wave group. CONCLUSIONS: Anterior Q wave infarction is associated with greater transmurality and more postinfarction left ventricular remodeling and dysfunction than is non-Q wave infarction.

Myocardial infarct expansion during indomethacin or ibuprofen therapy for symptomatic post infarction pericarditis. Influence of other pharmacologic agents during early remodelling.

Evidence of acute infarct expansion and the frequency of the acute infarct expansion syndrome (acute infarct dilatation and thinning associated with hypotension and left ventricular failure but no evidence of new necrosis) occurring at two days or more after a first acute Q-wave myocardial infarction were studied using serial two-dimensional echocardiography in 221 consecutive patients (100 anterior, 121 inferior). Patients with symptomatic pericarditis were treated with indomethacin (group 1, n = 73) or ibuprofen (group 2, n = 49) and those without symptomatic pericarditis received neither drug (group 3, n = 99). The overall frequency of the acute infarct expansion syndrome was 13% and 69% of these were among the pericarditis groups. The syndrome was significantly more frequent in group 1 (22%) than group 2 (8%) (P less than 0.05) or group 3 (9%) (P less than 0.025). Serial echocardiograms revealed more expansion with greater percentage increase in the infarct containing segment length in group 1 than group 2 or group 3 (18% versus 9% versus 9%, P less than 0.005). However, the decreases in infarct segment thickness were similar in groups 1 (24%) and 2 (25%) but greater (P less than 0.001) than in group 3 (7%). Despite similar infarct size and infarct thinning in groups 1 and 2, the degree of infarct expansion was greater and the infarct expansion syndrome more frequent in group 1. However, when allowance was made for the potential protective effect of prior use of intravenous nitroglycerin and concomitant use of nifedipine, indomethacin and ibuprofen had similar effects on expansion. Thus, indomethacin or ibuprofen should be used with caution after Q-wave infarction so as to avoid further expansion. The fact that short term use of other drugs might modify infarct remodelling should be considered in studies attempting to assess efficacy of one particular drug.(ABSTRACT TRUNCATED AT 400 WORDS)

Cardiac amyloidosis: combined use of two-dimensional echocardiography and electrocardiography in noninvasive screening before biopsy.

Cardiac amyloidosis (CA) presenting with intractable congestive heart failure, electrocardiographic (ECG) normal or low voltage, and conduction or rhythm disturbances, is rapidly fatal. During life, CA often mimics other cardiomyopathies so that definitive diagnosis depends on demonstration of amyloid on myocardial biopsy. On two-dimensional echocardiography (2-D echo), nonspecific features, such as increased ventricular wall thicknesses, predominant diastolic dysfunction, and diffuse myocardial "sparkling," are consistently found in CA. The combined presence of these 2-D echo features and normal or low voltage on ECG is highly suggestive of CA, allows differentiation from other cardiomyopathies, and might be useful in noninvasive screening before myocardial biopsy.

Evaluation of biventricular involvement in hypotensive patients with transmural inferior infarction by two-dimensional echocardiography.

Hypotension in inferior myocardial infarction (IMI) may be due to extensive involvement of the right ventricle (RV), left ventricle (LV), or both. We verified this hypothesis in 24 patients with IMI and hypotension (systolic blood pressure less than 100 mm Hg), within 48 hours of admission, by means of two-dimensional echocardiography (2DE). We measured the extent of regional RV and LV asynergy (akinesis and/or dyskinesis) in parasternal short-axis sections at mitral, chordal, midpapillary muscle, and low papillary muscle levels. Initial right heart catheterization revealed predominant RV dysfunction in 16 patients (group 1) and predominant LV dysfunction in eight patients (group 2). For all patients, the initial 2DE revealed: (1) biventricular asynergy involving the posterior RV, posterior LV, and posterior interventricular septum; (2) a wide range of values for the extent of asynergy (RV 21% to 90%; LV 19% to 48%); and (3) a direct correlation between peak creatine kinase levels and percentage of LV asynergy (r = 0.80, p less than 0.001) or percentage of RV plus LV asynergy (r = 0.72, p less than 0.001). Although the extent of LV asynergy was similar in the two groups (34% vs 34%, NS), the extent of RV asynergy was greater in group 1 than in group 2 (57% vs 30%, p less than 0.001). More important, the ratio of RV/LV asynergy was greater for group 1 than group 2 (1.75 vs 0.89, p less than 0.001), and this difference in ratios between the two groups was also found in 2DE studies at 10 days and 6 months. A RV/LV asynergy ratio value of 1.1 provided clear separation between the groups. Thus, the RV/LV asynergy ratio on an initial 2DE can clarify the clinical syndrome of hypotension in patients with IMI. An increased asynergy ratio might identify those patients with predominant RV involvement.

Carcinoid tumor of the thymus associated with recurrent pericarditis.

A 49-year-old man with carcinoid tumor of the thymus presented with the clinical picture of acute pericarditis. Recurrent bouts persisted after removal of the tumor without other evidence to indicate tumor recurrence. There were no associated manifestations of an endocrine disorder.

Hypothermic coronary perfusion for myocardial protection during aortocoronary bypass.

Numerous methods have been used in an attempt to prevent myocardial injury that results from the interruption of aortic flow during cardiac operations. The authors describe a relatively simple means of inducing cardioplegia during coronary bypass surgery by coronary perfusion with cold lactated Ringer's solution through the aortic root. When the results following the employment of hypothermic coronary perfusion for intraoperative cardioplegia were compared with those obtained without its use, the procedure was found to confer a degree of intraoperative myocardial protection and appeared to lead to a decrease in intraoperative myocardial infarction, subendocardial ischemia and intraoperative mortality.

The assessment of function of left ventricle and patency of aorta-coronary bypass after operation. A study of systolic time intervals.

The effect of aorta-coronary bypass surgery on left ventricular function was evaluated in 39 patients by cardiac catheterization and recording of the systolic time intervals (STI) before and an average of 4.5 months following myocardial revascularization. All patients were in sinus rhythm, had normal QRS intervals on the electrocardiogram, and had taken no medication for at least 3 weeks prior to the study. The STI was unchanged postoperatively in patients with the following characteristics: freedom from angina; heart rate not more than 15 beats greater than the preoperative level; all grafts patent; and no progression of disease in coronary arteries. Deterioration in left ventricular function after operation as represented by shortened left ventricular ejection time, (LVET) prolonged pre-ejection period (PEP), and increased ratio of PEP/LVET was found in patients with the following characteristics: persistent angina; heart rate more than 14 beats faster than the preoperative level; occlusion of any grafts; progression of disease in the coronary arteries; evidence for postoperative myocardial infarction. Worsening of left ventricular performance as determined by STI was more apparent in patients with occluded grafts and no collateral circulation than in those with occluded grafts and collateral circulation which may have offered protection against ischemia. These investigations supported the use of STI in assessing changes in left ventricular function after coronary bypass and, by inference, in assessing the status of the graft.

Acromegaly, the systolic click syndrome, and group D streptococcal endocarditis.

A syndrome consisting of an apical systolic click and late systolic murmur appeared over a period of three months in a patient with acromegaly. Levels of growth hormone were highest during this interval. As a result of group D streptococcal endocarditis three months later, the patient sustained cerebral embolism and acquired free mitral regurgitation from ruptured chordae tendineae. During follow-up over 18 months, neither the level of growth hormone nor the degree of mitral regurgitation changed significantly.

Intraventricular blocks in acute myocardial infarction.

The electrocardiograms and clinical records of 171 patients with a first recognized myocardial infarction (AMI) were reviewed in order to study the incidence and clinical significance of intraventricular blocks (IVB), especially hemiblocks, when other conditions which could have influenced the prognosis were excluded. Patients with left anterior hemiblock had higher SGOT levels (p less than 0.01), higher incidence of arrhythmias (p less than 0.01) and congestive heart failure (p less than 0.01) compared to the control group without IVB. Isolated left posterior hemiblock was infrequent and did not appear to influence the course of AMI. Bundle branch and bifasicular blocks were associated with the highest incidence of complications and mortality (47 percent), but these patients were older (p less than 0.01) and also had higher SGOT levels than the control group (p less than 0.05). To some extent, mortality and incidence of complications appeared to be related to the degree of myocardial damage, which in turn produced the IVB rather than to the conduction abnormality itself.