Impact energy absorption by specimens from the upper end of the human femur.

A cadaveric biomechanical study was performed to investigate the fracture energy absorbed by strips of bone from the proximal femur in relation to age and gender, under impact loading conditions. Four groups (young male, young female, old male, old female) of four cadaveric proximal femurs were used in each case. Four bone strips were taken from the neck and four from the subtrochanteric area and these were tested under dynamic-impact conditions using the Charpy impact test. The fracture energy was calculated as the energy needed to achieve fracture per unit area, and expressed in J/m2. Bone specimens from young males are significantly tougher under impact conditions to those of females (p = 0.001), whereas between the old male and female groups, fracture energy does not significantly differ (p = 0.165). There was also significant difference (p < 0.0005) between the young and the old groups in both genders. The fracture energy absorption of the subtrochanteric area compared to that of the femoral neck for the same group of age and gender is in general slightly higher for all groups. In conclusion, gender in the young age group played a significant role in bone resistance in breaking whereas in the older age group it played a less important role.

Evolutionary pattern and prognostic importance of heart rate variability during the early phase of acute myocardial infarction.

AIMS: To investigate the evolution of time domain heart rate variability in the early phase of acute myocardial infarction (MI) and assess its prognostic ability. METHODS: We analysed several measures of heart rate variability (SDNN, SDANN, SDNN index, RMSSD) in 138 patients at days 0, 1 and 5+/-1 after hospital admission for acute MI. Results were correlated with infarct site, clinical variation and clinical outcome (death, MI, PTCA, CABG surgery). RESULTS: Measures of heart rate variability (SDNN, SDANN and SDNN index) declined during the first 24 h after acute MI (P<0.01) and increased to admission levels after about 5 days. SDNN values on day 0, 1 and 5 respectively were: 86+/-35, 75+/-28 and 87+/-27 ms. Patients with anterior infarction had lower heart rate variability than patients with inferior infarction on all test days but similar evolution patterns. After 3 years of follow-up there were 12 cardiac deaths (8.7%) and six resuscitated arrests and 33 (24%) new MIs, or revascularisation procedures. The evolutionary pattern of heart rate variability was similar in survivors to those who died although values were generally lower. Mortality was significantly higher in the group with SDNN<50 ms at day 1 (P<0.01) and 5 (P<0.05), but not at day 0. CONCLUSIONS: Our findings show that autonomic imbalance, already evident on the day of the acute event, progresses further over the next 24 h and recovers over the next few days. Low heart rate variability as early as 24 h after acute MI may be a useful predictor of cardiac mortality and contribute to the early risk stratification and therapeutic management of patients.

Influence of biological factors on lipid and fibrinogen measurements in young men. An epidemiological study in 2009 recruits.

AIMS: The aim of the present study was to detect significant relationships between lipid and fibrinogen measurements and several biological factors in young men. METHODS AND RESULTS: Medical history was obtained, and plasma lipids, lipoprotein (a) and fibrinogen levels were measured in 2009 male Greek army recruits (mean age 22.37+/-3.03 years) not taking any drugs. Plasma levels were as follows: total cholesterol, 171+/-34 mg x dl(-1), low density lipoprotein (LDL) cholesterol, 111+/-34 mg x dl(-1), high density lipoprotein (HDL) cholesterol, 45+/-10 mg x dl(1), and triglycerides, 74+/-32 mg x dl(-1). Lipoprotein (a) and fibrinogen were 18+/-13 and 278+/-67 mg x dl(-1). The atherosclerotic index, calculated as the ratio of total cholesterol/HDL, was 4+/-1. Analysis of multivariate models that included potentially confounding factors revealed the following: body mass index, season of year during which blood examinations were performed, alcohol consumption, and place of residence were found to be significantly associated with plasma levels of total cholesterol, LDL-cholesterol, fibrinogen and the atherosclerotic index in the pooled population. Season and physical activity were significantly associated with HDL-cholesterol, whereas season and family history of acute myocardial infarction were associated with triglycerides levels. Body mass index, family history of myocardial infarction and physical activity were associated with lipoprotein (a). CONCLUSION: Body mass index, season, alcohol consumption and place of residence are markers of plasma lipid profile and fibrinogen in young men. A family history of acute myocardial infarction and physical activity are related to lipoprotein (a).