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Biomedical subjects

M Hajjar

Publications and source records attributed to M Hajjar.

8 recordsLinked to original sources
PubMed2005

[Survey of cardiovascular risk assessment and the behaviour of a sporting population].

In order to better understand the risk factors and behaviour of a general sports population, a questionnaire was handed to 603 consecutive sportsmen of various disciplines during a specific sports medicine consultation and a half-marathon. Among the discovered risk factors, smoking was the most common (19.3% for the entire study population), predominantly in the youngest group (26%). A resting ECG had been performed very frequently within the previous year in those over 40 years (86.5%), but less often in the younger sportsmen (44.8%). An exercise test had also very often been performed in those aged over 40 years (69.2 vs 10.6%). Behaviour associated with cardiovascular risk was common. Undertaking physical activity while febrile (58%) and smoking just before or after exertion (13.1%) were widespread behaviours. This population appeared casual in its approach to possibly suspicious cardiac symptoms of exercise, particularly the females and paradoxically the subjects doing the most sport. Lastly, only a minority of sportsmen knew the telephone number for the emergency medical service (45%) or claimed to be competent at first aid (32%). This survey underlines a practice relatively in accordance with the recommendations for detecting cardiovascular pathology, but shows a failure of preventive education.

Adult↗
PubMed1999

Measurement of sarcomere length during fast contraction of muscle fibers by digital image analysis.

A low-cost, high-resolution (spatial and temporal) image analysis system was developed to measure sarcomere length (Sl) during fast twitch of isolated striated muscle fibers at different temperatures. Fiber images were examined during twitch with an imaging rate of 220 Hz. To increase temporal resolution beyond 220 Hz, consecutive temporally shifted image sequences (N sequences) were acquired. Individual or average Sl was directly measured from a horizontal profile without spatial-frequency assessment. Measurement precision (E) was determined and expressed as: E(%) = 100xPs/(IsxSl), where Ps is the pixel size and Is the involved sarcomere number. At 18 degrees C during isometric twitch, Sls were measured with 220 Hz temporal and 0.2% spatial resolutions. Sl shortened in the central region (0.21+/-0.12 microm) as tension developed, reaching a maximal shortening of 8.09 + 2.05% (at rest, Sl = 2.59+/-0.05 microm, n = 4) in 32.5+/-1.96 ms. At 30 degrees C, Sl variations were examined with 880 Hz temporal resolution, in which case maximal S1 shortening was reached in 15.74+/-1.99 ms, and then decreased to 5.19+/-1.97% (at rest, S1 = 2.6+/-0.06 microm). The twitch tension developed by the whole fiber was recorded and compared with sarcomere length behavior. Sarcomere length variations in the central region were representative of overall developed tensions at 18 and 30 degrees C.

Animals↗
PubMed1998

[Major statistical software usable in epidemiology].

Quality assurance of biostatistical data analysis is becoming mandatory. The aim of this review of statistical software was to guide uses who are faced with the increasing number of these tools. A list of softwares was obtained from statisticians and computer scientists, computerized databases, computer science lay press, and commercial documents. The softwares were described and their possibilities measured. The following functions were studied: functions considered as essential (descriptive analysis, Student's t, Mann-Whitney or Wilcoxon, ANOVA, Kruskall-Wallis, Pearson's chi 2, Fisher's exact test, Pearson's r), survival and multivariate analysis (logistic regression, proportional hazards modelling, times series). User-friendliness and quality of graphs were also studied. Among the 220 listed softwares, 26 could be considered as general softwares and were extensively analyzed. Statistical softwares may be classified into four categories: easy-to-use general public softwares with limited functions, such as EPI INFO; simple reference softwares with satisfactory user-friendliness and performing most of the statistical analyses, such as PCSM, STATISTICA or STATA; complex reference softwares intended for statisticians (EPILOG PLUS, SAS); specific cases such as EGRET performing only multivariate analysis or SUPERANOVA performing only analysis of variance. Such a review should be regularly updated.

Analysis of Variance↗
PubMed1995

[Prognosis and predictive factors of mortality in patients with inoperable coronary disease].

In the period between September 1979 and December 1986, 105 out of 2,178 consecutive patients with coronary artery disease (men 93, women 12; age : 58.1 +/- 10 years; previous myocardial infarction : 67%) were considered inoperable because of poor distal coronary circulation (84.8%), left ventricular dysfunction (3.8%) or both (11.4%). Fifty-four clinical, ergometric and angiographic parameters were examined at inclusion. The mean follow-up was 69 +/- 40.2 months (1 to 146 months). The Kaplan Meier 10 year survival rate was 43%. Only 25% of the population remained free of major cardiac events. Multivariate analysis showed that only the coronary angiographic score had a significant predictive value. The authors conclude that the long-term prognosis of these patients is poor. Some did undergo coronary bypass surgery secondarily, and their prognosis was good, suggesting that revascularisation, even if only partial and at high risk, should be considered.

Adult↗
PubMedDate not supplied

[Psychotic disorders. Higher incidence during travels in Asia].

Psychiatric disorders in French travellers accounted for 15 to 20 percent of medical repatriations arranged by medical assistance companies. The authors of this study dealt with the cases recorded during a 1-year period by one of these companies, and they analysed the psychiatric episodes in relation to the main features of the subject's journey. These episodes usually occurred in summer and affected young or middle-aged people. More than half of them were psychotic disorders which were significantly more frequent in Asia than elsewhere and were unrelated to drug addiction or anti-malarial prophylaxis. The management of these patients by the medical assistance company has been discussed.

Adolescent↗