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Biomedical subjects

V Boyko

Publications and source records attributed to V Boyko.

81 records · Page 5Linked to original sources
PubMed1995

Digoxin and increased mortality among patients recovering from acute myocardial infarction: importance of digoxin dose. The SPRINT Study Group.

Digoxin therapy has been suggested to increase mortality risk in survivors of acute myocardial infarction. Since digoxin is a drug with a narrow therapeutic/toxic ratio, we raised the hypothesis that the association between digoxin and post myocardial infarction mortality may have a dose-dependent relationship. The purpose of this study was to evaluate this hypothesis. We retrospectively analyzed data from 1731 survivors of acute myocardial infarction. At the time of hospital discharge, 175 patients (10%) were taking digoxin. The exact dosage of digoxin was ascertained in 153 (87%) patients. Patients were divided into two groups based on the weekly dosage of digoxin at hospital discharge: The first group included 41 patients who were treated with a low dose (< or = 1.5 mg per week, usually 0.125 mg daily). The second group included 112 patients treated with a full dose (> 1.5 mg per week, usually 0.25 mg daily). Both groups were comparable with regard to mean age, gender, history of prior myocardial infarction, diabetes mellitus, hypertension, and prior angina. There were no significant differences in the incidence of in-hospital complications, such as heart failure, atrial fibrillation, ventricular tachycardia, ventricular fibrillation, and postinfarction angina. One year mortality was significantly higher among patients treated with a full dose [19 of 112 (17%)] than patients treated with a low dose of digoxin [1 of 41 (2%); p < 0.02] Multivariate analysis performed by the Cox proportional hazards model identified treatment with a full dose of digoxin as an independent determinant associated with increased death during the first year after myocardial infarction (hazard ratio 10.7; 95% confidence interval 1.4-80.5). Thus, mortality among myocardial infarction survivors treated with digoxin was related to a full-dose therapy. Patients treated with a low dose experienced a low mortality rate. Our findings raise concern that digoxin may exert a dose-dependent deleterious effect upon the survival of patients recovering from acute myocardial infarction.

Adult↗
PubMed1995

Improved posterobasal segment function after thrombolysis is associated with decreased incidence of significant mitral regurgitation in a first inferior myocardial infarction.

OBJECTIVES: This study was designed to investigate the association between wall motion abnormalities and the occurrence of ischemic mitral regurgitation in patients with a first inferior or posterior myocardial infarction and to reassess the role of thrombolytic treatment in these patients. BACKGROUND: We previously demonstrated that thrombolytic therapy reduces the incidence of significant mitral regurgitation in patients with a first inferior myocardial infarction, but the mechanisms responsible for this decrease were not clear. METHODS: Wall motion score on two-dimensional echocardiography (16 segments) and mitral regurgitation grade (0 to 3) on Doppler color flow imaging were assessed in 95 patients (in 47 after thrombolysis) at 24 h, 7 to 10 days and 1 month after myocardial infarction. Significant mitral regurgitation was defined as moderate or severe (grade 2 or 3). RESULTS: Multivariate analysis revealed that the presence of an advanced wall motion abnormality of the posterobasal segment of the left ventricle was the most significant independent variable associated with significant mitral regurgitation: odds ratio (OR) 15.0, 90% confidence interval (CI) 1.4 to 165.6 at 24 h; OR 2.8, CI 0.9 to 9.3 at 7 to 10 days; OR 4.2, CI 1.2 to 11.4 at 1 month. Thrombolysis reduced the prevalence of advanced wall motion abnormalities in the posterobasal segment at 24 h (55% vs. 75%, OR 0.5, CI 0.2 to 0.99), 7 to 10 days (44% vs. 73%, OR 0.3, CI 0.1 to 0.7) and 1 month (36% vs. 56%, OR 0.4, CI 0.2 to 0.9). CONCLUSIONS: There is a strong association between advanced wall motion abnormalities in the posterobasal segment and significant mitral regurgitation. In this study group, thrombolysis reduced the prevalence of advanced wall motion abnormalities in the posterobasal segment and thereby reduced the incidence of significant mitral regurgitation.

Echocardiography↗
PubMed1995

The predictive value of admission heart rate on mortality in patients with acute myocardial infarction. SPRINT Study Group. Secondary Prevention Reinfarction Israeli Nifedipine Trial.

The purpose of this study was to assess the predictive value of admission heart rate (HR) for in-hospital and 1 year post-discharge mortality in a large cohort of patients hospitalized for acute myocardial infarction (MI). Data were derived from the SPRINT-2 secondary prevention study population, and included 1044 patients (aged 50-79), hospitalized in 14 coronary care units in Israel with acute MI in the years 1985-1986, before the beginning of thrombolytic therapy in acute MI. Demographic, historical and medical data were collected for each patient. All deaths during initial hospitalization and 1 year post-discharge were recorded. In-hospital mortality was 5.2% for 294 patients with HR < 70 beats/min, 9.5% for 532 patients with HR 70-89 beats/min, and 15.1% for 323 patients with HR > or = 90 beats/min (p < 0.01). One year post-discharge mortality was 4.3% for patients with HR < 70 beats/min, 8.7% for patients with HR 70-80 beats/min and 11.8% for patients with HR > or = 90 beats/min (p < 0.01). An increasing trend of mortality with higher HR was confined to patients with mild CHF (p = 0.02) and likely to patients with absent CHF (p = 0.06), but this post hoc observation requires confirmation in larger groups. The combination of high admission HR (> or = 90 beats/min) and a systolic blood pressure < 120 mmHg was a powerful predictor of in-hospital mortality. Multivariate analysis showed that admission HR was an independent risk factor for in-hospital and 1 year post-discharge mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Clinical predictors of reinfarction among men and women after a first myocardial infarction. SPRINT Study Group. Secondary Prevention Reinfarction Israeli Nifedipine Trial.

Independent clinical factors predicting reinfarction in the 1st year following an initial myocardial infarction were identified among 900 women and 2,795 men. Women were older (65.8 vs. 59.3 years; p < 0.001) but tended to suffer from reinfarction at a rate similar to that of men (6.9 vs. 5.6%, p = 0.17). Cumulative 1-month, 1- and 5.5-year all-cause mortality following the first infarction was higher among women who sustained reinfarction (43, 52 and 74%, respectively) than among men (29, 30 and 51%, respectively, p < 0.01 for each). Independent clinical predictors for recurrent myocardial infarction among women were (adjusted relative odds): peripheral vascular disease (3.2), postinfarction angina (2.3), diabetes mellitus (2.2), radiographic evidence of cardiomegaly (1.9), anterior location of the first infarction (2.0), congestive heart failure (1.8), prior angina (1.6) and age (10 years) increment (1.2). Predictive variables for men were: anterior infarct location (1.7), peripheral vascular disease (1.6, prior stroke (1.5), prior angina (1.4), systemic hypertension (1.3) and age (10 years) increment (1.1). Our data indicate (a) different cardiac risk factors for reinfarction among men and women after a first myocardial infarction, and (b) a prognostic advantage for men over women following reinfarction.

Aged↗
PubMed1995

Asymptomatic hyperglycemia in coronary heart disease: frequency and associated lipid and lipoprotein levels in the bezafibrate infarction prevention (BIP) register. The BIP Study Group.

BACKGROUND: The lipid profile of patients with type-II diabetes is characterized by low levels of high-density lipoprotein cholesterol, hypertriglyceridemia, and increased levels of lipoprotein (a), all of which may affect the prognosis in patients with atherosclerotic cardiovascular disease. This study aimed to assess the prevalence of asymptomatic hyperglycemia and the associated lipid profile in a large group of patients with documented coronary heart disease. METHODS: From February 1990 to October 1992, 14,326 patients aged 45-74 years with documented coronary heart disease (a history of myocardial infarction or angina pectoris) were screened for inclusion in a secondary prevention study using bezafibrate retard. All screened patients underwent a medical examination and a blood test after fasting for 14 h. Asymptomatic hyperglycemia was defined as a fasting blood glucose level of 140 mg/dl or above in patients with no previous history of diabetes mellitus. RESULTS: The prevalence of asymptomatic hyperglycemia was 4%, with no differences between the sexes or age groups. Total cholesterol and triglyceride levels were significantly higher and the high-density lipoprotein cholesterol level significantly lower in asymptomatic hyperglycemic than in normoglycemic patients. After multiple adjustments, the relative risk of death was 1.75 and 1.71 in patients with diabetes or asymptomatic hyperglycemia compared with those with no glycemic disorders. CONCLUSION: Asymptomatic hyperglycemia was detected in 4% of patients with ischemic heart disease. The lipid profile in these 4% resembles that of patients with confirmed diabetes, and their morbidity and mortality may therefore be higher than that of normoglycemic patients. Repeated assessment of glucose levels in patients with coronary heart disease is mandatory.

Aged↗
PubMed1994

A major cellular substrate for protein kinases, annexin II, is a DNA-binding protein.

We have screened a human cDNA expression library in lambda gt11 for clones encoding Alu-binding proteins using direct binding of labeled Alu DNA to recombinant phage lysates fixed on a membrane, and isolated a clone 98% identical in sequence to the well-known substrate of protein kinases, annexin II, which was suggested earlier to play a role in transduction of mitogenic signals and DNA replication. A diagnostic property of annexins is their binding to phospholipids in the presence of calcium ions, and we have found that the interaction of proteins of human nuclear extracts with Alu subsequences is suppressed by Ca/phosphatidylserine liposomes, suggesting overlapping of Ca/phospholipid- and DNA-binding domains in annexin II.

Amino Acid Sequence↗
PubMed1994

Nucleotide sequence and organization of eight 3' open reading frames of the citrus tristeza closterovirus genome.

The citrus tristeza closterovirus (CTV) RNA genome was cloned as cDNA generated from both CTV-specific double-stranded RNA and genomic RNA, and the sequence of the 3' 7292 nucleotides was determined. The sequenced portion contained eight open reading frames potentially encoding, in the 5' to 3' direction, proteins with the apparent molecular weights of 65, 61, 27, 25 (capsid protein, CP), 18, 13, 20, and 23 kDa, and a potential noncoding region of 277 nucleotides. The 65-kDa protein is a viral homolog of cellular hsp70 heat shock proteins (hsp), the 61-kDa protein is distantly related to the hsp90 proteins, and the 27-kDa protein is a diverged copy of the CP. Database searches did not identify any protein sequences of significant similarity to the remaining four ORFs downstream of the CP. A specific four-gene module consisting of the hsp70 protein, the hsp90-related protein, the diverged copy of the CP, and the CP itself was found to be common in organization between CTV and beet yellows closterovirus. All four proteins in this module were highly conserved, indicating that these viruses probably have evolved from a common ancestor.

Amino Acid Sequence↗
PubMedDate not supplied

Echocardiographic left ventricular remodeling and pseudohypertrophy as markers of hypovolemia. An experimental study on bleeding and volume repletion.

BACKGROUND: Monitoring intravascular volume during surgery, especially in major cardiovascular procedures is necessary for appropriate fluid restoration and the maintenance of an adequate cardiac output. In estimating preload, both standard hemodynamic and echocardiographic parameters have been limited. The purpose of this study was to further define the effects of induced hypovolemia on the echocardiographic parameters. In particular, we sought to show whether a decrease in echocardiographic left ventricular area and volume was associated with a significant increase in left ventricular wall thickness (left ventricular pseudohypertrophy) and with changes in LV function. In addition, we sought to investigate the effects of rapid restoration of blood volume on cardiac dimensions and function. METHODS AND RESULTS: Seven anesthetized pigs underwent systemic and right heart pressures and cardiac output measurements. Two-dimensional echocardiographic parasternal long- and short-axis views were obtained during graded bleeding by rapid withdrawal of blood from an arterial cannula, with increments of 5% each up to 30% of calculated blood volume. After completion of the bleeding, the entire amount of the blood withdrawn was retransfused within 4 to 5 minutes. Both hemodynamic and echocardiographic measurements were performed at baseline, immediately after the completion of each stage of bleeding and after blood restoration. Mean (+/- standard deviation) left ventricular wall thickness (mean of septal and posterior wall thickness) was 6.3 +/- 0.1 mm at baseline, 8.3 +/- 1.5 mm at peak bleeding, and 6.2 +/- 0.1 after restoration (p < 0.01). Left ventricular mass did not change during the experiment. Left ventricular end-diastolic volume was 62.8 +/- 20.3 ml at baseline, 37.5 +/- 12.4 ml at peak bleeding (p < 0.0001), and 65.9 +/- 16.7 ml after blood restoration (p < 0.001 compared with 30% bleeding). H/r ratio (posterior wall thickness divided by left ventricular radius) increased from 0.29 +/- 0.07 at baseline to 0.50 +/- 0.19 at peak bleeding returning to 0.26 +/- 0.04 after restoration. Left ventricular ejection fraction was 0.53 +/- 0.10 at baseline and 0.55 +/- 0.20 at peak bleeding (not significant), decreasing to 0.38 +/- 0.11 after blood restoration (p < 0.05 compared with 30% bleeding). End-diastolic volume correlated closely with right atrial pressure (r = -0.82), capillary wedge pressure (r = -0.78), and stroke volume (r = 0.74). Left ventricular ejection fraction inversely correlated with left ventricular end-diastolic volume (r = -0.48) and with end-systolic wall stress (r = -0.62). The changes in interventricular septal and posterior wall thickness were inversely related to left ventricular end-diastolic volume (r = -0.72 and -0.35, respectively). CONCLUSIONS: This study shows that transient concentric left ventricular remodeling (pseudohypertrophy), a phenomenon previously described in cardiac tamponade and during rapid atrial pacing is commonly seen during hypovolemia. This new sign may further enhance the echocardiographic estimation of left ventricular preload.

Animals↗