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Biomedical subjects

B Savin

Publications and source records attributed to B Savin.

8 recordsLinked to original sources
PubMed2003

Occurrence of electromyographic and ventilatory thresholds in professional road cyclists.

The temporal relationship between the electromyographic (EMG) and ventilatory thresholds was investigated during incremental exercise performed by eight professional road cyclists. The exercise, performed on a cycloergometer, started at 100 W with successive increments of 26 Wx min(-1) until exhaustion. Gas exchange and the root mean square value of EMG (RMS) from eight lower limb muscles were examined throughout the exercise period. Professional cyclists achieved a maximal oxygen consumption, i.e. VO(2max), of 5.4 (0.5) l x min(-1) [74.6 (2.5) ml x min(-1) x kg(-1), range: 67.8-82.4 ml x min(-1) x kg(-1)] and a maximum power ( W(max)) of 475 (30) W (range: 438-516 W). Our results showed at least the occurrence of a first EMG threshold (EMG(Th1)) in 50% (gastrocnemius lateralis) of the subjects and a second EMG threshold (EMG(Th2)) in 63% (gastrocnemius medialis). EMG(Th1) occurred significantly before the first ventilatory threshold (VT(1)), i.e. at 52 (2)% and 62 (9)% of W(max), respectively. Inversely, no significant difference was observed between the occurrence of EMG(Th2) and the second ventilatory threshold (VT(2)), i.e. at 86 (1)% and 89 (7)% of W(max), respectively. These results suggest that the use of EMG may be a useful non-invasive method for detecting the second ventilatory threshold in most of the muscles involved in cycling exercise.

Adult↗
PubMed1999

Silent myocardial ischemia in patients with diabetes: who to screen.

OBJECTIVE: Silent myocardial ischemia (SMI) is more common in diabetic patients than in the general population. However, the exact prevalence of SMI is not known, and routine screening is costly. The purpose of this 1-year study was to estimate the prevalence of SMI and define a high-risk diabetic population by systematically testing patients with no symptoms of coronary artery disease (CAD). RESEARCH DESIGN AND METHODS: The criteria for inclusion in this study were age (between 25 and 75 years), duration of diabetes (>15 years for type 1 diabetes, 10 years for type 2 diabetes with no cardiovascular risk factors, and 5 years for type 2 diabetes with at least one cardiovascular risk factor), and absence of clinical or electrocardiogram (ECG) symptoms of CAD. For 1 year, 203 patients were screened, including 28 women and 45 men with type 1 diabetes (aged 41.5+/-10.9 years, mean duration of diabetes 20.9+/-7.7 years [mean +/- SD]) and 61 women and 69 men with type 2 diabetes (aged 60.7+/-8.7 years, duration of diabetes 16.5+/-7.1 years). Exercise ECG was the first choice for screening method. If exercise ECG was not possible or inconclusive, thallium myocardial scintigraphy (TMS) with exercise testing and/or dipyridamole injection was performed. If any one of these tests was positive, coronary angiography was carried out and was considered to be positive with a stenosis of > or =50%. RESULTS: Positive screening results were obtained in 32 patients (15.7%). Coronary angiography demonstrated significant lesions in 19 patients (9.3%) and nonsignificant lesions in 7 patients (1 false-positive result for exercise ECG and 6 false-positive results for TMS). Coronary angiography was not performed in six patients. All but 3 of the 19 patients (15 men and 4 women) in whom silent coronary lesions were detected presented with type 2 diabetes. The main differences between the 16 type 2 diabetic patients presenting with coronary lesions and the type 2 diabetic patients without SMI were a higher prevalence of peripheral macroangiopathy (56.2 vs. 15.1%, respectively, P < 0.01) and a higher prevalence of retinopathy (P < 0.05). No correlation was found between SMI and duration of diabetes, HbA1c level, renal status, or cardiovascular risk factors except for family history of CAD. CONCLUSIONS: The results of this study allowed us to determine a high-risk group for SMI in the diabetic population. SMI with significant lesions occurs in 20.9% of type 2 diabetic male patients who are totally asymptomatic for CAD. Based on these findings, we recommend routine screening for male patients in whom the duration of type 2 diabetes is >10 years or even less when more than one cardiovascular risk factor is present.

Adult↗
PubMed1994

[Flecainide exercise induced left bundle branch with chest pain].

Ischaemia has been the suggested mechanism of simultaneous left bundle branch block and chest pain on effort with normal coronary angiography. This hypothesis is very controversial and was not the mechanism in the two new cases of this syndrome. The two patients in whom effort pain and left bundle branch block were observed had been treated for paroxysmal supraventricular tachycardia with flecaine. Withdrawal of the anti-arrhtymic resulted in the disappearance of this syndrome. In these cases, the ischaemic mechanism could be excluded without ambiguity. The flecaine was the only cause of rate-related LBBB by slowing conduction in the left bundle branch with no effects on coronary reserve. It would seem that LBBB alone was the cause of chest pain. The absence of coronary artery disease was confirmed in the first patient and the diagnosis was highly improbable in the second.

Aged↗
PubMed1982

[Spasm, stenosis and thrombosis. Their role in the genesis of myocardial infarction].

A 42 year old patient underwent coronary angiography 3 hours after the onset of inferior myocardial infarction with the object of local thrombolysis therapy. Complete proximal obstruction of the right coronary artery was relieved mechanically by the catheter. This was associated with a return of the ST segment to the isoelectric line but Q waves persisted in Lead III and AVF. A second injection showed 70 p. 100 stenosis at the site of the obstruction and the radiolucent appearances of thrombus below it. This was followed by 4 successive periods of ST elevation as the right coronary artery reoccluded. These phenomena were relieved by injection of nitroglycerine suggesting a spastic mechanism. The radiolucent image of thrombus disappeared and was replaced by amputation of a distal branch of the right coronary artery. Further coronary opacification showed good run-off beyond the stenosis and reappearance of the distal branch. This case suggests that three factors played a role in the mechanism of infarction: stenosis accompanied by spasm and thrombosis.

Adult↗
PubMed1981

[Serial measurement of serum levels of amikacin. Value in therapy].

Amikacin serum levels were measured 256 times in 65 patients admitted into the intensive care unit for various reasons over 18 months. These measurements confirmed the dosage of 5 micrograms per kg repeated every 8 hours in patients with normal renal function. Forty eight hours before the first measurement, a control assay is essential to check that there is no residual antibiotic and that the antibacterial activity of the serum is zero. After this a single weekly control is sufficient to check that the residual level is effective and non toxic, i.e. between 2 and 6 micrograms per ml. However, in patients with acute renal insufficiency, there are three dosage schemas which should be used depending on the creatinine level. These three schemas are nevertheless not sufficient to continue effective therapy without a risk of toxic side effects. It is therefore necessary to check both the pack levels and the residual levels regularly from the beginning of treatment. Two to three weekly controls are essential to avoid a risk of toxic side effects.

Adolescent↗