НАДЕЖНОСТЬ КОНВЕЙРНОГО ТРАНСПОРТА

Досліджено питання комплексної надійності функціонування конвеєрних ліній при відкритій розробці корисних копалин. Наведено статистичні закони розподілу для напрацювання на відмову і термінів служби роликових опор для конвеєрних ліній. Побудовано діаграму причин і результатів для системати- зації причин простоїв конвейєрних ліній з переміщення гірської маси в кар'єрах. Исследован вопрос комплексной надежности функционирования конвейерных линий при открытой разра- ботке полезных ископаемых. Приведены статистические законы распределения для наработки на отказ и сроков службы роликовых опор для конвейерных линий. Построена диаграмма причин и результатов для систематизации причин простоев конвейерных линий по перемещению горной массы в карьерах

Proinflammatory cytokines in acute myocardial infarction with and without cardiogenic shock

Background: Inflammatory response is an important feature of acute coronary syndromes and myocardial infarction (MI). The prognostic value of proinflammatory cytokines in patients with acute MI complicated by cardiogenic shock is unknown. Methods and results: In 41 patients admitted with acute MI (age 60 ± 11 years, six females, 19 Killip class IV) serial plasma concentration of tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and interleukin 1 receptor antagonist (IL-1Ra) were measured. Seven patients with cardiogenic shock (CS) developed a systemic inflammatory response syndrome (SIRS). Patients with CS—particularly those who developed SIRS—showed significantly higher cytokine levels than patients with uncomplicated MI. In patients with CS and SIRS peak levels of IL-1Ra were 223,973 pg/ml, IL-6 252.8 pg/ml and TNF-α 7.0 pg/ml. In CS without SIRS IL-1Ra levels were 19,988 pg/ml, IL-6 109.3 pg/ml and TNF-α 3.8 pg/ml. In uncomplicated MI peak IL-1Ra levels were 1,088 pg/ml, IL-6 34.1 pg/ml and TNF-α 2.6 pg/ml. Conclusions: The inflammation-associated cytokines TNF-α, IL-6 and IL-1Ra are significantly elevated in patients with MI complicated by CS when compared to patients with uncomplicated MI. Among shock-patients IL-1Ra levels are promising diagnostic markers for early identification of patients developing SIRS, heralding a poor outcom

Do women have impaired regional systolic function in hypertensive heart disease? A 3-dimensional echocardiography study

AIMS: In pressure overload left ventricular (LV) hypertrophy, gender-related differences in global LV systolic function have been previously reported. The goal of this study was to determine regional systolic function of the left ventricle in male and female patients with hypertensive heart disease. METHODS AND RESULTS: Regional LV function was analyzed from multiplane transesophageal echocardiography with three-dimensional (3D) reconstruction of the left ventricle. In 24 patients (13 males and 11 females), four parallel (2 basal and 2 apical) equidistant short axis cross-sections from base to apex were obtained from the reconstructed LV. In each short axis 24 wall-thickness measurements were carried out at 15 degrees intervals at end-diastole and end-systole. Thus, a total of 192 measurements were obtained in each patient. Wall thickening was calculated as difference of end-diastolic and end-systolic wall thickness, and fractional thickening as thickening divided by end-diastolic thickness. Fractional thickening and wall stress were inversely related to end-diastolic wall thickness in both, males and females. Females showed less LV systolic function when compared to males (p<0.001). However, when corrected for wall stress, which was higher in females, there was no gender difference in systolic function. CONCLUSION: There are regional differences in LV systolic function in females and males which are directly related to differences in wall stress. Thus, gender-related differences in LV regional function are load-dependent and not due to structural differences

Prognostic value of stress-gated 99m-technetium SPECT myocardial perfusion imaging: Risk stratification of patients with multivessel coronary artery disease and prior coronary revascularization

BACKGROUND: This study assessed the prognostic value of stress-gated 99mTc-sestamibi myocardial perfusion SPECT (MPS) in patients with multivessel coronary artery disease (CAD) and prior revascularization according to the presence and severity of ischemia. METHODS AND RESULTS: We studied the outcome of 472 patients with multivessel CAD and prior revascularization (coronary angioplasty, 290 patients; bypass surgery, 182 patients), who underwent exercise or dipyridamole 99mTc-sestamibi MPS for evaluation of ischemia. Visual scoring of perfusion images used 20 segments and a 5-point scale. Gated post-stress EF was automatically calculated. Endpoints included hard events: cardiac death (CD) and nonfatal myocardial infarction (MI). During a mean follow-up of 3.0 ± 1.0 years, 37 hard events occurred, including CD in 15 (3%) and MI in 22 (5%) patients. In a risk-adjusted multivariable Cox model, a history of prior MI, diabetes, abnormal MPS, moderate-to-severe ischemia, and post-stress EF <35% were important predictors of cardiac events. Four-year risk-adjusted survival was 97.9% for normal MPS, 87.3% for abnormal MPS with ischemia, and 82.1% for moderate-to-severe ischemia. CONCLUSIONS: Among patients with previous coronary revascularization, stress-gated 99mTc-sestamibi MPS provides prognostic information for the prediction of cardiac events. A normal perfusion scan confers an excellent prognosis and an exceedingly low hard event rate (<1%/year). The presence of moderate-to-severe ischemia or a post-stress EF <35% identifies patients at highest risk of subsequent cardiac events