Effect of set configuration on hemodynamics and cardiac autonomic modulation after high‐intensity squat exercise

The aim of this study was to compare the effect of two different high‐intensity resistance exercise (RE) set configurations on the following: systolic blood pressure (SBP), rate pressure product (RPP), heart rate (HR) variability (HRV), and HR complexity (HRC). Ten well‐trained males performed three parallel squat sets until failure (traditional training; TT) with the four repetitions maximum load (4RM), and a rest of 3 min between sets. Thereafter, participants performed a cluster training session (CT) of equated load but with resting time distributed between each repetition. Dependent variables were recorded before, during, and after RE. Mean SBP (25·7 versus 10·9% percentage increase; P = 0·016) and RPP (112·5 versus 69·9%; P = 0·01) were significantly higher in TT. The decrease in HRV after exercise and the drop of HRC during exercise were similar in CT and TT. Change of standard deviation of normal RR intervals after TT correlated with change in SBP (r = 0·803; P = 0·009) while the change of Sample Entropy during exercise correlated with the increment of RPP during CT (ρ = ?0·667; P = 0·05). This study suggests that set configuration influences acute cardiovascular responses during RE. When intensity, volume and work‐to‐rest ratio are equated, CT is less demanding in terms of SBP and RPP. A greater hemodynamic response during exercise would be associated with a faster parasympathetic recovery.     

Changes in coronary haemodynamics and myocardial metabolism at rest and during exercise after a cardiotonic drug (prenalterol) in patients with coronary artery disease

Summary. To elucidiate the myocardial metabolic and haemodynamic effects of an inotropic drug in patients with coronary artery disease (CAD) without evident congestive heart failure (CHF), the acute effects of prenalterol were studied in nine patients. Patients with documented CAD by leftsided cardioangiography and end-diastolic pressure >15 mm Hg were included in the study. They were examined at rest and during supine exercise at a level just below their anginal threshold before and after prenalterol. At rest, rate pressure product (RPP) increased by 40% (P<0·01), cardiac index rose 20% (P<0·01), cardiac venous flow (CVF) increased by 18% (P<0·05), and myocardial oxygen consumption (MVO₂) increased by 20% (P<0·05) after prenalterol administration. Despite a decrease in mean pulmonary capillary venous pressure (PCV) of 40% (P<0·01), myocardial lactate extraction fell significantly (P<0·01) and lactate production was observed in three of nine patients compared to before prenalterol administration. During exercise, RPP increased by 20% (P<0·01), cardiac index remained unchanged, CVF increased by 25% (NS) and MV0₂ showed a tendency to an increase (NS) after prenalterol administration. Mean PCV pressure decreased by 30% (P<0·01). Myocardial lactate extraction was markedly reduced during exercise (P<0·01) and five of nine patients showed lactate production compared to that before prenalterol administration. Thus, despite a decrease in left ventricular filling pressure, increased myocardial oxygen demand occurred after acute administration of prenalterol. Prenalterol and probably similar inotropic drugs should be used cautiously in patients with CAD without clinical evidence of congestive heart failure.     

Reproducibility of orthostatic changes in cerebral oxygenation in healthy subjects aged 70 years or older

In the elderly, standing can frequently be accompanied by blood pressure (BP) changes and cerebral symptoms such as dizziness, fall, or even syncope, but this may vary from day‐to‐day. Therefore, we aimed to investigate the reproducibility of orthostatic responses of cerebral cortical oxygenation and systemic haemodynamics in elderly subjects. In 27 healthy elderly subjects (age 70–84 years), changes in systolic BP (SBP), diastolic BP (DBP), heart rate (HR) and stroke volume (SV) were continuously monitored by Finapres (Finger Arterial Pressure), and changes in oxyhaemoglobin ([O₂Hb]) and deoxyhaemoglobin ([HHb]) concentrations were continuously measured over the right frontal cortex by near infrared spectroscopy (NIRS) during supine rest and 10 min of active standing on two separate occasions. SBP and DBP increased by 6·7 ± 15·4 mmHg (P<0·05, mean ± SD) and 8·2 ± 6·4 mmHg (P<0·01), respectively, whereas HR increased by 9·5 ± 5·0 bpm (P<0·01) and SV decreased by –8·3 ± 7·4 ml (P<0·01) during standing on the first occasion. [O₂Hb] decreased by –3·9 ± 2·9 μmol l^–1 (P<0·01), while [HHb] increased by 1·8 ± 2·2 μmol l^–1 (P<0·01). Group‐averaged orthostatic changes in cortical oxygenation and systemic haemodynamics were very similar on the two occasions, although an intraindividual variation was found. Cortical oxygenation changes were not accompanied by severe cerebral symptoms. Active standing induced reproducible group‐averaged frontal cortical oxygenation declines in healthy elderly subjects, although an intraindividual day‐to‐day variability was present, possibly related to the variability of orthostatic BP responses. These findings indicate that cerebral autoregulation fails to compensate completely for postural changes in elderly subjects, which might predispose elderly subjects to ischaemic cerebral symptoms.     

The effect of cooling on toe systolic pressures in subjects with and without Raynaud's syndrome in the lower extremities

Summary. The effect of changes in local and body temperature on the toe systolic pressures was studied in 20 subjects with and 30 without Raynaud's syndrome in the toes. The pressures were significantly lower in the group with Raynaud's syndrome under all experimental conditions (P < 0·01). The pressures were significantly lower during body cooling than during body warming in both groups (P < 0·01). The mean decrease with body cooling was 58 mmHg in the group with Raynaud's syndrome and 24 mmHg in the control subjects (P < 0·01). During body cooling pressures fell to less than 30 mmHg in 70% of subjects with Raynaud's syndrome and in 3% of the controls. Local cooling from 30 to 10°C during body cooling resulted in a significant mean decrease in pressure of over 40 mmHg in both groups (P < 0·01) and the pressure fell below 30 mmHg in over 90% of the group with and in 26% of those without Raynaud's attacks. The results indicate the importance of body cooling and local temperature in the mechanism of vasospasm in the toes. They are also relevant to the diagnosis of Raynaud's syndrome in the lower limbs and have implications for the testing of patients with arteriosclerotic occlusion since erroneously low pressure values could be obtained in tests when the feet are cold.     

Tissue oxygenation,strength and lactate response to different blood flow restrictive pressures

This study aimed to determine whether changes in initial restrictive pressures (IRP, tightness of the cuff before inflation with air) affect tissue oxygenation, lactate production and leg strength before, during and after knee extension exercises. The cuff was positioned on the right thigh, and the IRP of either 40–45 or 60–65 mmHg were applied randomly prior to inflating the cuff to the final restrictive pressure (the pressure reached after inflating the cuff with air). Subjects performed four sets (30, 15, 15 and 15 reps) of isotonic knee extensions with 1‐min rest between sets. Tissue oxygenation and blood lactate levels were assessed prior to, during and after exercise, and leg strength was assessed pre‐ and postexercise. There were significant condition by time interactions (P<0·01) and main effects for both condition (P<0·01) and time (P<0·01) for tissue oxygenation, deoxyhaemoglobin, total haemoglobin. Significant main effects were detected for both condition (P<0·01) and time (P<0·01) for leg strength values. There was only a significant time main effect for lactate concentrations. This study is the first to show that a higher IRP had a significant impact on percent tissue oxygenation, leg strength and deoxygenated haemoglobin accumulation during exercise.     

Endothelin‐1: increased plasma clearance,pulmonary affinity and renal vasoconstriction in young smokers

Pulmonary and renal haemodynamics and elimination of endothelin‐1 (ET‐1) were studied in six young smokers in response to 20 min intravenous infusion of ET‐1 (4 pmol kg^–1 min^–1) after smoking. At 20 min of ET‐1 infusion fractional ET‐1 extractions in the lungs and kidneys were 60 ± 2 and 60 ± 7%, respectively. Cardiac output and renal blood flow (RBF) fell by 18 ± 4% (P<0·05) and 34 ± 5% (P<0·01). Mean systemic arterial pressure increased (P<0·05) whereas pulmonary pressures were unchanged. Compared with previously published data in non‐smokers ( 38 , 39 ) basal arterial ET‐1 and ET‐1‐values during ET‐1 infusion were lower with a more rapid return to basal value. Smokers had higher pulmonary extraction of ET‐1 at the same pulmonary arterial concentration (P<0·05). RBF reduction was more pronounced (P<0·05). Systemic vascular resistance increased while pulmonary vascular resistance did not increase as in non‐smokers. Increased plasma clearance and more efficient pulmonary elimination of ET‐1 lowers the arterial level in young smokers. In addition ET‐1 evokes more pronounced renal vasoconstriction in these individuals.     

Changes in cardiac autonomic regulation after prolonged maximal exercise

Harmful cardiac events occurs frequently after exercise. However, the cardiac autonomic regulation after vigorous exercise is not well known. This study was designed to assess heart rate (HR) variability before and after a 75 km cross‐country skiing race. HR variability was assessed by using standard statistical measures along with spectral and quantitative Poincarè plot analysis of HR variability in 10 healthy male subjects (age 36 ± 11 years). The average HR was at the same level 1 day after the race as before the race, but on the second day, HR was significantly lower (P<0·001) compared with the prerace and 1 day after values. The normalized high‐frequency (HF) spectral component of HR variability (nuHF) was lower (P<0·01) on the first day after the maximal exercise compared with the pre‐exercise values but returned to or even exceeded the prerace level on the second day (P<0·01). The changes in short‐term R‐R interval variability analysed from the Poincaré plot were similar to those observed in the HF spectral component. The normalized low‐frequency (LF) spectral component of HR variability (nuLF) was higher (P<0·01) on the first day after the exercise compared with the prerace levels and it also returned to the pre‐exercise level or even dropped below it on the second day after the race. The mean time it took the HF spectral component to return to the pre‐exercise level was 4·2 ± 4·2 h (ranging from 0 to 12 h). This recovery time correlated inversely with the maximal oxygen consumption (VO_2max) measured during the bicycle exercise test before the skiing race (r=?0·712, P<0·016). The cardiac vagal outflow is blunted for several hours after prolonged vigorous exercise. The recovery time of reduced vagal outflow depends on individual cardiorespiratory fitness and there is an accentuated rebound of altered autonomic regulation on the second day after prolonged exercise.     

Menstrual cycle phase does not influence gender differences in experimental pain sensitivity

Influence of menstrual cycle phase on experimental pain sensitivity in women and on gender differences in pain sensitivity was examined in 48 men and 49 women in response to cold pressor, heat, and ischemic pain. Each woman was tested at three points in their menstrual cycle in randomized order, the early follicular, late follicular, and luteal phases, while men were also tested three times, controlling for number of days between test sessions. Cycle phase was confirmed via serum hormone levels. As expected, women were significantly more sensitive to cold pain (p < .01), to heat pain (p < .0001), and to ischemic pain (p < .01) than men. However, pain perception during each task was not influenced by the menstrual cycle in women, nor did the menstrual cycle influence the magnitude of the gender differences in pain sensitivity. These results indicate that although women are more sensitive to a variety of noxious stimuli than men, menstrual cycle phase does not appear to moderate those differences in healthy men and women.     

不同月经状态下正常子宫ADC值变化

目的 探讨不同月经状态下正常子宫ADC值的变化特征。方法 收集绝经前和绝经后因子宫以外的盆腔器官病变接受MR检查的女性患者78例,根据其月经状态分为月经期（n=18）、卵泡期（n=20）、黄体期（n=20）和绝经后（n=20）。在ADC伪彩图中测量子宫各层结构（内膜、结合带、肌层）的ADC值,分析并比较不同结构、不同月经状态下子宫ADC值的差异。结果 相同月经状态下,子宫内膜、结合带、肌层间ADC值总体差异均有统计学意义（P均<0.001）,子宫肌层、内膜、结合带ADC值依次降低,两两比较差异均有统计学意义（P均<0.05）。子宫各层结构在不同月经状态的ADC值总体差异均有统计学意义（P均<0.05）。子宫内膜ADC值在月经期、卵泡期和黄体期的两两比较差异有统计学意义（P均<0.05）,绝经后与月经期、黄体期有统计学意义（P均<0.05）;结合带ADC值在月经期、卵泡期与黄体期两两比较差异有统计学意义（P均<0.05）,绝经后与黄体期差异有统计学意义（P<0.05）;肌层ADC值在绝经后与月经期、卵泡期和黄体期差异均有统计学意义（P均<0.05）。结论 不同月经状态下正常子宫各层结构ADC值变化较大。利用ADC值评判子宫疾病时,应考虑不同月经状态下的基线ADC值变化。     

A comparison of dynamic contrast‐enhanced CT and MR imaging‐derived measurements in patients with cervical cancer

This work is to compare the kinetic parameters derived from the DCE‐CT and ‐MR data of a group of 37 patients with cervical cancer. The modified Tofts model and the reference tissue method were applied to estimate kinetic parameters. In the MR kinetic analyses using the modified Tofts model for each patient data set, both the arterial input function (AIF) measured from DCE‐MR images and a population‐averaged AIF from the literature were applied to the analyses, while the measured AIF was used for the CT kinetic analysis. The kinetic parameters obtained from both modalities were compared. Significant moderate correlations were found in modified Tofts parameters [volume transfer constant(K^trans) and rate constant (k_ep)] between CT and MR analysis for MR with the measured AIFs (R = 0·45, P<0·01 and R = 0·40, P<0·01 in high‐K^trans region; R = 0·38, P<0·01 and R = 0·80, P<0·01 in low‐K^trans region) as well as with the population‐averaged AIF (R = 0·59, P<0·01 and R = 0·62, P<0·01 in high‐K^trans region; R = 0·50, P<0·01 and R = 0·63, P<0·01 in low‐K^trans region), respectively. In addition, from the Bland–Altman plot analysis, it was found that the systematic biases (the mean difference) between the modalities were drastically reduced in magnitude by adopting the population‐averaged AIF for the MR analysis instead of the measured ones (from 51·5% to 18·9% for K^trans and from 21·7% to 4·1% for k_ep in high‐K^trans region; from 73·0% to 29·4% for K^trans and from 63·4% to 24·5% for k_ep in low‐K^trans region). The preliminary results showed the feasibility in the interchangeable use of the two imaging modalities in assessing cervical cancers.     

Determination of baroreflex gain using auto-regressive moving-average analysis during spontaneous breathing

The heart rate component of the arterial baroreflex gain (BRG) was determined with auto-regressive moving-average (ARMA) analysis during each of spontaneous (SB) and random breathing (RB) protocols. Ten healthy subjects completed each breathing pattern on two different days in each of two different body positions, supine (SUP) and head-up tilt (HUT). The R–R interval, systolic arterial pressure (SAP) and instantaneous lung volume were recorded continuously. BRG was estimated from the ARMA impulse response relationship of R–R interval to SAP and from the spontaneous sequence method. The results indicated that both the ARMA and spontaneous sequence methods were reproducible (r=0·76 and r=0·85, respectively). As expected, BRG was significantly less in the HUT compared to SUP position for both ARMA (mean ± SEM; 3·5 ± 0·3 versus 11·2 ± 1·4 ms mmHg^–1; P<0·01) and spontaneous sequence analysis (10·3 ± 0·8 versus 31·5 ± 2·3 ms mmHg^–1; P<0·001). However, no significant difference was found between BRG during RB and SB protocols for either ARMA (7·9 ± 1·4 versus 6·7 ± 0·8 ms mmHg^–1; P=0·27) or spontaneous sequence methods (21·8 ± 2·7 versus 20·0 ± 2·1 ms mmHg^–1; P=0·24). BRG was correlated during RB and SB protocols (r=0·80; P<0·0001). ARMA and spontaneous BRG estimates were correlated (r=0·79; P<0·0001), with spontaneous sequence values being consistently larger (P<0·0001). In conclusion, we have shown that ARMA-derived BRG values are reproducible and that they can be determined during SB conditions, making the ARMA method appropriate for use in a wider range of patients.     

Effects of dobutamine and salbutamol on haemodynamics and atrial natriuretic factor in patients with severe congestive heart failure

Summary. The influence of two cardiac inotropic drugs, dobutamine and salbutamol, on plasma atrial natriuretic factor (ANF) was investigated in 20 patients with congestive heart failure. All were in New York Heart Association class-III or IV. The patients underwent right heart catheterization with determination of central pressures, cardiac output, and pulmonary arterial plasma ANF during incremental infusions with dobutamine or salbutamol. Fourteen patients completed the study. Both drugs induced comparable increases in cardiac index and decreases in total systemic vascular resistance (P < 0·01) without significant changes in central pressures. Heart rate rose after salbutamol (P < 0·05), but not after dobutamine. No changes in plasma ANF were observed after either of the drug infusions. ANF secretion rate was calculated from simultaneous measurements of ANF in right atrial and pulmonary arterial plasma before and after salbutamol infusion, and median values rose more than seven-fold (P < 0·05). The results demonstrate that ANF secretion rate is augmented after β-adrenergic agents, possibly by a direct β₂-adrenergic stimulation, in patients with severe congestive heart failure, and that changes in plasma ANF are an insufficient measure of ANF release when patient samples are small.     

Is there a difference in the electromyographic activity of the pelvic floor muscles across the phases of the menstrual cycle?

[Purpose] To evaluate the electrical activity of the pelvic floor muscle in women during the follicular, ovulatory, and luteal phases of the menstrual cycle and its correlation with estradiol and total testosterone levels. [Subjects and Methods] This cross-sectional study involved 30 women with ovulatory menstrual cycles. Total testosterone and estradiol levels were measured and the muscle tone and maximum voluntary contraction of the pelvic floor muscles were evaluated using surface electromyography. [Results] Muscle tone was significantly lower during the follicular (21.1±3.3 μV) and ovulatory (27.1±5.9 μV) phases than the luteal phase (30.4±4.1 μV). The maximum voluntary contraction was not different across phases. The estradiol level on the 7th day of the menstrual cycle showed a strong positive correlation with muscle tone and maximum voluntary contraction, and the testosterone level was positively correlated with muscle tone on the 21st day. [Conclusion] Women have better muscle tone during the luteal phase. The muscle tone and maximum voluntary contraction were strongly correlated with the estradiol level on the 7th day, and the muscle tone was correlated with the testosterone level on the 21st day of the menstrual cycle. These findings suggest that hormonal fluctuations during the menstrual cycle alter pelvic floor muscle activity.Key words: Electromyography, Pelvic floor, Menstrual cycle     

Whole‐body vibration dosage alters leg blood flow

The effect of whole‐body vibration dosage on leg blood flow was investigated. Nine healthy young adult males completed a set of 14 random vibration and non‐vibration exercise bouts whilst squatting on a Galileo 900 plate. Six vibration frequencies ranging from 5 to 30 Hz (5 Hz increments) were used in combination with a 2·5 mm and 4·5 mm amplitude to produce twelve 1‐min vibration bouts. Subjects also completed two 1‐min bouts where no vibration was applied. Systolic and diastolic diameters of the common femoral artery and blood cell velocity were measured by an echo Doppler ultrasound in a standing or rest condition prior to the bouts and during and after each bout. Repeated measures MANOVAs were used in the statistical analysis. Compared with the standing condition, the exercise bouts produced a four‐fold increase in mean blood cell velocity (P<0·001) and a two‐fold increase in peak blood cell velocity (P<0·001). Compared to the non‐vibration bouts, frequencies of 10–30 Hz increased mean blood cell velocity by approximately 33% (P<0·01) whereas 20–30 Hz increased peak blood cell velocity by approximately 27% (P<0·01). Amplitude was additive to frequency but only achieved significance at 30 Hz (P<0·05). Compared with the standing condition, squatting alone produced significant increases in mean and peak blood cell velocity (P<0·001). The results show leg blood flow increased during the squat or non‐vibration bouts and systematically increased with frequency in the vibration bouts.     

Evaluation of menstrual cycle effects on morphine and pentazocine analgesia

Studies have demonstrated menstrual cycle influences on basal pain perception, but direct evidence of menstrual cycle influences on analgesic responses has not been reported in humans. Our aim was to determine whether the magnitude of morphine and pentazocine analgesia varied across the menstrual cycle. Sixty-five healthy women, 35 taking oral contraceptives (OC) and 30 normally cycling (NOC), underwent experimental pain assessment both before and after intravenous administration morphine (0.08 mg/kg) or pentazocine (0.5 mg/kg) compared to saline placebo. Both active drug and placebo were administered once during the follicular phase and once during the luteal phase. Measures of heat, ischemic, and pressure pain sensitivity were obtained before and after drug administration. Change scores in pain responses were computed to determine morphine and pentazocine analgesic responses, and medication side effects were recorded. The data were analyzed using mixed-model analyses of variance. NOC women showed slightly greater heat pain sensitivity in the follicular vs luteal phase, while the reverse pattern emerged for OC women (P = 0.046). Also, OC women showed lower pressure pain thresholds compared to NOC women (P < 0.05). Regarding analgesic responses, NOC women showed greater morphine analgesia for ischemic pain during the follicular vs the luteal phase (P = 0.004). Likewise, side effects for morphine were significantly higher in NOC women in the follicular phase than in the luteal phase (P = 0.02). These findings suggest that sex hormones may influence opioid responses; however, the effects vary across medications and pain modalities and are likely to be modest in magnitude.     

Validation of the acetylene rebreathing method for measurement of cardiac output at rest and during high-intensity exercise

The use of the acetylene rebreathing method to estimate cardiac output (CO) during high-intensity exercise, which may be influenced by recirculation of acetylene, has not been validated. This study was designed to validate the acetylene rebreathing method to measure CO during high-intensity exercise using the direct Fick method. CO was measured at rest and during exercise at 25%, 50%, 75% and 90% of the nine subjects maximum oxygen uptake (VO _2max) by the direct Fick and acetylene rebreathing method. CO measured by the acetylene rebreathing method correlated with work rate (r=0·90, P<0·01) and with oxygen uptake (r=0·94, P<0·01). The correlation coefficient of CO between both methods was r=0·91 (P<0·01). There was no significant difference in CO measured by each method at rest as well as at each work rate. The difference in CO between each method was greater at lower CO than at higher CO. At 90% of VO _2max, the CO measured by acetylene rebreathing was nearly identical to that measured by the Fick method. It can be concluded that acetylene rebreathing for measurement of CO is valid not only at rest but also during exercise, especially during high-intensity exercise.     

Volumetric measurements of peripheral oedema in clinical conditions

Water‐displacement volumetry can be used for quantifying the volume of the leg. However, not much is known about its application in patients with peripheral oedema of cardiopulmonary origin. We measured the reproducibility of a water‐displacement apparatus with a solid object and in ten non‐oedematous clinical patients (group A). The day‐to‐day variability of the leg volume was assessed in the same group. The diurnal variability was assessed in ten patients with persisting peripheral oedema (group B). The effect of treatment on the severity of peripheral oedema was evaluated in another nine patients with peripheral oedema, who were in need of diuretic treatment (group C). Volumetric results were compared to the ankle circumference method and the body weight method. The coefficient of variation was 0·16% in the fixed object and 0·47% in group A. The day‐to‐day variability was 1·52% after 1 day and 1·76% after a mean interval of 4·8 days. In group B, leg volume and circumference increased during the day (5·9%, P<0·001, and 2·4%, P<0·01, respectively), while body weight remained unchanged. In group C, leg volume, circumference and body weight decreased significantly after treatment (13·1%, P<0·01, 7·1%, P<0·05, and 5·9%, P<0·05). The correlation between the changes in volume and body weight was poor (r=0·37, P=0·33). In conclusion, (1) water‐displacement volumetry is highly reproducible, (2) a diurnal variability of peripheral oedema was found, and (3) volumetry is a suitable tool for monitoring peripheral oedema, while the body weight method appears to be less accurate.     

Effect of nasal air temperature on FEV1 and specific airways conductance

We investigated whether changes in nasal air temperature affect specific airway conductance (SGaw) and one second forced expiratory volume (FEV₁) in 10 asthmatic patients with a history of cold‐sensitive asthma and eight healthy subjects. An air‐stream (0·6 l s^–1) of –15°C, +22°C or +37°C was blown into both nostrils during a Valsalva manoeuvre. Each provocation consisted of 10 puffs of air, each of 15 s duration, at 1 min intervals. Before and at regular intervals after the provocations, SGaw and FEV₁ were determined. In asthmatics, after cold air provocation, SGaw fell 23% (P<0·01) and FEV₁ 8% (P<0·01). After the warm air provocations, SGaw rose 15% (P<0·01) and FEV₁ 6% (P<0·01). After the ambient air provocations, no significant changes occurred in SGaw or FEV₁. In the healthy subjects, the nasal provocations caused no significant changes in lung function. The present study shows that cold air in the nose causes a slight obstruction and warm air possibly a slight dilatation of the lower airways in patients with a history of cold‐sensitive asthma but not in healthy subjects.     

Evaluation of impaired dynamic cerebral autoregulation by the Mueller manoeuvre

Arterial blood pressure (ABP) shows polyphasic changes during the Mueller manoeuvre (voluntary negative intrathoracic pressure). The aim of the present study was to investigate (1) whether these changes could be applied to detect impaired dynamic cerebral autoregulation (dCA) in carotid stenosis and (2) whether the degree of indicated impairment correlates with transfer function phase as another current measure for dCA (deep breathing method) and CO₂‐reactivity. We examined 13 patients with severe unilateral carotid artery stenosis and 16 age‐matched controls during 15‐s Mueller manoeuvres (MM) at ?30 mmHg using bilateral transcranial Doppler sonography and non‐invasive ABP recordings (Finapres, 2300, Ohmeda, Englewood, CO, USA). After an initial biphasic oscillation, cerebral blood flow velocity (CBFV) and ABP decreased to below baseline. CBFV reincreased in controls and on contralateral sides in patients 6·0 s (3·8–9·5 s, median and range) after the onset of the decrease, despite a further fall in ABP. CBFV over the affected side revealed a significantly delayed reincrease (8·0 (5·6–10·3) s; P<0·01) combined with a relatively flat and inertial amplitude behaviour. An applied autoregulation index derived from the MM (mROR), phase shift and CO₂‐reactivity were severely reduced on the affected side in patients (P<0·01). Reduction of the mROR correlated significantly with reduction of phase shift (r=0·69; P=0·002) and CO₂‐reactivity (r=0·78; P=0·002). In conclusion, the different cerebral haemodynamic pattern during the MM in patients is likely to reflect impaired dCA. The degree of indicated impairment correlates with that of transfer function phase and CO₂‐reactivity. Therefore, the MM represents a convenient method for grading of compromised cerebral haemodynamics in patients with carotid artery stenosis.     

Myoglobin and enzyme adaptations in erector spinae muscles in thoracal scoliosis

Summary. Bilateral biopsies from the erector spinae muscles were taken during surgery from 10 females and two males (mean age 14, range 13–17 years) with thoracal scoliosis for 6 years (range 2–11 years). The biopsies were analysed for myoglobin (MYO), citrate synthase (CS) and creatine kinase MB (CK-MB). The severity of scioliosis was estimavoted by Cobb's angle, the greater the angle the more severe the disease. The convex/concave side ratio (CVX/CCV) was for CS l·3±0·4 (P<0·01), CK 0·9 ± 01 (P<0·05), CK-MB 1·6±0·4 (P<0·01) and for MYO 1·1±0·2 (P>0·05). No significant correlations were found between the CVX/CCV for CS, CK or CK-MB on the one hand and the Cobb's angle on the other. The CVX/CCV for MYO was, however, directly related to the angle (r= 0·80, P<0·01). For the lower range of angles (≤59°) the CVX/CCV for MYO was below unity (0·88, P>0·05) and for the larger angles (>59°) above unity (1·23, P<0·05). In conclusion, a dissociation in the adaptive response of m. erector spinae in scoliosis between mitochondrial enzyme and myoglobin content was demonstrated.