bluuebunny/crossref_metadata_2025 huggingface dataset:
Non‐invasive investigation of vascular compression in patients with thoracic outlet syndrome
Authors: Sällström Johan , Thulesius Olav
Published: April 2008

Summary. Three hundred and seventy‐seven patients with brachial pain and 63 controls have been examined regarding presence of symptomatic compression of the brachial plexus and subclavian vessels (Thoracic Outlet Syndrome=TOS). Each patient was examined clinically and by Doppler flowmetry. Two hundred and thirty (61%) had moderate to pronounced compression of the brachial plexus and 11 (2·9%) isolated compression of the subclavian artery or vein. One hundred and twenty‐nine patients had symptoms not related to TOS. The prevalence of TOS was almost twice as common in women as in men, 1·76:1. The TOS patients were younger than the non‐TOS patients, P<0·05. There was a significant correlation between arterial compression measured by Doppler flowmetry and the presence of compression of the plexus, P < 0·001. But the validity of this method was not satisfactory, giving both false positive and negative results. Furthermore, there was a very good correlation between arterial compression assessed clinically and by Doppler flowmetry, P< 0·001. Thus, the diagnosis of TOS is still a clinical judgement, the Doppler technique adding very little and any significant vascular compression being easily detected by clinical assessment.
Single detector renography with 131I‐Hippuran and 99mTc‐DTPA: a comparison
Authors: Wranne Bengt , Svedberg John
Published: April 2008

Summary. 131I‐Hippuran and 99mTc‐DTPA were injected intravenously within a few seconds. By appropriate dose and window selection, simultaneous Hippuran and DTPA renograms with discrete detectors were obtained from 33 kidneys (17 patients). Uptake and excretion ratios were significantly lower and peak time occurred slightly but significantly later in the DTPS than in the Hippuran renograms.
Myocardial extraction of insulin in patients with valvular aortic stenosis
Authors: Ekroth R. , Emanuelsson H. , Hjalmarsson Å. , Holm J. , Schersten T. , Waagstein F. , Waldenström A. , William‐Olsson G.
Published: April 2008

Summary. In eight patients with valvular AS myocardial extraction of insulin was determined before and after intravenous infusion of 25 g of glucose. There was a significant extraction of insulin after the glucose infusion which was related to the arterial insulin concentration. It was also related to the gradient over the stenotic valve, which may explain the low plasma insulin levels previously found in patients with valvular aortic stenosis.
The effect of physical training in elderly subjects with special reference to energy‐rich phosphagens and myoglobin in leg skeletal muscle
Authors: Möller P. , Brandt R.
Published: April 2008

Summary. Energy‐rich phosphagens and myoglobin were determined in leg skeletal muscles of seven, 61‐ to 80‐year‐old, apparently healthy male subjects. The study was repeated after the participants had been exercising on an ergometer bicycle twice weekly for 6 weeks. Before training, myoglobin and all intramuscular energy‐rich phosphagens were within the range recorded for a larger series of subjects of similar age. When re‐examined after training the myoglobin level remained the same but creatine decreased significantly and the ratio between phosphocreatine and total creatine increased. A slight but significant rise was also observed for the ATP/ADP ratio. It is concluded that age‐related changes of intramuscular phosphagens in elderly subjects in part might be due to physical inactivity.
Influence of fibre ingestion on carbohydrate utilization and absorption
Authors: Wahren J. , Juhlin‐Dannfeltx A. , Björkman O. , DeFronzo R. , Felig P.
Published: April 2008

Summary. To evaluate the mechanism whereby the addition of fibre to the diet lowers postprandial plasma glucose levels, the effects of ingestion of 10 g guar gum, a non‐absorbable storage polysaccharide, on carbohydrate utilization and absorption were examined in healthy subjects. Total glucose utilization independent of gastrointestinal absorption of glucose was determined by the hyperglycaemic clamp technique in which constant hyperglycaemia is maintained with a variable intravenous infusion of glucose. Net splanchnic glucose uptake was also measured. As compared to a control study without guar, ingestion of guar failed to increase total glucose utilization or the uptake of glucose by splanchnic tissues. In contrast, when guar was ingested together with 25 g D‐xylose, a nonmetabolizable pentose, blood xylose levels were 25–40% lower than when xylose was ingested alone (P<0·01). We conclude that the plasma‐glucose‐lowering effects of high‐fibre diets are a consequence of decreased carbohydrate absorption rather than increased total glucose utilization or augmented uptake of glucose by the liver.
Can body potassium of old people be predicted from anthropometric data?
Authors: Lye M. , Faragher E. B.
Published: April 2008

Summary. Body potassium was measured by whole body counting in a group of carefully screened healthy individuals, mean age 75 years. The results have been compared with values predicted by eight formulae in the literature derived using similar methods. The mean predicted results ranged from 87% to 102% of the mean observed level in male subjects and from 87% to 137% in female subjects. Individual male results range from 55% to 123% and in female subjects from 72% to 146% of the observed value. It is concluded that there are no published formulae which will adequately predict whole body potassium levels in old people—the very group likely by virtue of age‐related disease, to need measurements of body potassium.
Detection of coronary artery disease with gated cardiac blood‐pool scintigraphy: comparison of cold pressor test and dynamic exercise
Authors: Rootwelt K. , Erikssen J. , Nitter‐Hauge S. , Thaulow E.
Published: April 2008

Summary. Forty‐six subjects (11 normals with no cardiac disease, 13 persons with a ‘false’ positive exercise ECG test, and 22 patients with coronary artery disease) were investigated with ECG‐gated cardiac blood‐pool imaging at rest, during cold pressor stimulation, and during supine bicycle exercise. Changes in left ventricular ejection fraction and intervention induced regional wall motion abnormalities were measured. Cold pressure stimulation did not induce anginal pain in any person, but were generally found more unpleasant than dynamic exercise. Dynamic exercise detected significantly more coronary artery disease patients (20/22, 91%) than did cold stimulation (13/22, 59%) (P < 0·02). Specificity of dynamic exercise and cold stimulation was not significantly different. It is concluded that cold stimulation is less sensitive than dynamic exercise in the detection of patients with ischaemic heart disease with gated cardiac blood‐pool imaging.
Transcutaneous versus arterial oxygen tension during exercise in chronic pulmonary disease
Authors: Kornum Mogens , Oxhøj Henrik , Nielsen Gunner
Published: April 2008

Summary. Simultaneous transcutaneous (Ptc O2) and arterial (Pa O2) oxygen tension measurements were obtained at rest and during exercise in 15 subjects with known or suspected chronic lung disease. The overall correlation coefficient between Ptc O2 and Pa O2 was 0·74, and the mean difference between the two variables was — 1·9kPa (14 mmHg). The correlation coefficient was somewhat, but not significantly, higher during exercise (r=0·86) than at rest (r=0·58). Large random discrepancies between simultaneous observations of Ptc O2 and Pa O2 as well as between changes in Ptc O2 and changes in Pa O2 in individual subjects were observed. It is concluded that Ptc O2 cannot be substituted for Pa O2 in exercise testing applied in the diagnosis and assessment of lung disease.
Comparison of portable CdTe(CI) detectors with stationary NaI(TI) detectors for subcutaneous 133Xe disappearance measurements
Authors: Bojsen Jørgen , Kølendorf Klaus , Staberg Bent
Published: April 2008

Summary. 113Xe washout measurements from locally injected depots in the subcutaneous tissue of the thigh have been performed intermittently by a NaI(TI) detector placed 15 cm from the depot and a cadmium telluride [CdTe(CI)] detector fixed to the skin surface above the depot. In 19 experiments, the measurements were performed during rest, before and after bicycling and during circulatory arrest during an occlusion cuff pressure of 240–250 mmHg. The disappearance rates measured by the two detector systems showed a linear correlation(r = 0· 934, P < 0·001). However, the rate constants measured by the CdTe(CI) detector were an average of 1·48 times the values obtained by the NaI(TI) detector during a period of 1–4 h after the injection. The coefficient of variation of the proportionality factor is 3·3%. Only the central part of the local depot area is exposed to the CdTe(CI) detector. Using the Nal(TI) detector and lead shielding of the peripheral or central part of the depot area, it was demonstrated that the disappearance rates obtained reflect the measuring geometries. The correction itself is therefore due to differences in the measuring geometries of the two detector types, and possibly to diffusion and convection of xenon. For quantitative determination of the subcutaneous blood flow, the disappearance rate constants determined by the CdTe(CI) detector thus have to be corrected by division with the factor 1·48.
Early changes in oesophageal function in progressive systemic sclerosis: a comparison of manometry and radiology
Authors: Blom‐Bülow Berith , Sundström Gunnar , Jonson Björn , Tylén Ulf , Wollheim Frank A.
Published: April 2008

Summary. The characteristics of oesophageal dysfunction were studied with manometry and cine radiography in a recumbent position in 21 patients with typical progressive systemic sclerosis (PSS). Manometry was also performed in a matched control group. Only one patient had a completely normal manometry. Mean resting pressure in both the upper and lower oesophageal sphincters were significantly decreased in PSS. Twelve patients had no detectable peristalsis in the lower oesophagus. In the upper oesophagus, the mean pressure amplitude of the peristaltic wave was found to be lower than normal in all patients with detectable peristalsis. In some patients, the only feature of oesophageal dysfunction observed was an increased speed of the peristaltic wave in the middle and lower oesophagus. This is interpreted as an impaired coordination of the propulsive peristalsis. Neuromuscular dysfunction of the oesophagus in its full length was thus clearly demonstrated.

At cine radiography, three patients were judged as normal, and 13 patients had severe impairment of the peristaltic function in the distal two‐thirds of oesophagus.

Oesophageal scoring based on manometry correlated well to scoring based on radiography. Cine radiography of the recumbent patient gives adequate information for clinical purposes. Detection of early changes in the amplitude and speed of the propagation wave requires manometry.
Impedance pneumography for long‐term monitoring of respiration during sleep in adult males
Authors: Larsen Vagn Højkjær , Christensen Per‐Henrik , Oxhøj Henrik , Brask Torben
Published: April 2008

Summary. Impedance pneumography is based on the relationship between respired volume (ΔV) and changes of transthoracic impedance (Δ/Z/) during breathing. The impedance signal, the relationship between ΔV and Δ/Z/ and the success rate during long‐term recording was studied in 11 healthy adult males, aged 21–46, by a portable tape recorder (Oxford Medilog 4–24). The signals from the tape recorder (Δ/Z/), and from a spirometer (ΔV) were recorded simultaneously on a mingograph during normal breathing, apnoea, deep sighs, and coughs. The relationship between ΔV and Δ/Z/ was also analysed on an X‐Y recorder. Δ/Z/ was delayed in relation to ΔV and during one respiratory cycle the relationship was not linear. The time constant of Δ/Z/ was 6 s. A significant correlation was found between peak values of ΔV and Δ/Z/ for 0 < ΔKV<2·5 litres. Long‐term recording of Δ/Z/ during one night's sleep resulted in a success rate of 63–100%, mean 90%. Invalidation of the impedance signal was caused by overloading (81%) and interference (19%). It is concluded that the Medilog respiratory recorder enables determination of respiratory frequency, periods of apnoea and a semiquantitative estimate of volume, but artifacts may invalidate the signal.
The size and strength of the quadriceps muscles of old
Authors: Men Young , Young Archie , Stokes Maria , Crowe Morgan
Published: April 2008

Summary. The mean isometric strength of the stronger quadriceps muscles of 12 healthy men in their seventies was 39% less than that of 12 healthy men in their twenties (P < 0–001). The cross‐sectional area of the quadriceps was measured at mid‐thigh, by ultrasound scanning; the older men's stronger quadriceps were 25% smaller (P < 0–001).

The ratio of the stronger quadriceps' strength to its cross‐sectional area was very similar in the old men to values obtained previously for both old and young women, but averaged 19% less than in the young men (P < 0–02). Quadriceps size and strength were correlated in the old men (P= 0–77, P= 0–03) but not in the young men (r= 0.15). The principal axis of the relationship between quadriceps size and strength in the old men was very similar to those previously reported for both old and young women.

The quadriceps strength of some young men is greater than would be expected from the size of the muscle.
GAS EXCHANGE IN CHRONIC PULMONARY DISEASE
Authors: Wagner Peter D.
Published: April 2008

Patients with asthma, chronic obstructive lung disease and diffuse inter stitial fibrosis were studied., These three groups of patients illustrate very different patterns of V̇A/Q̇ mismatching in general, consistent with the known pathology of their disease. Some common threads run through all three groups. One is that the level of hypoxemia in an individual depends critically on the interplay between mixed venous PO2 and the degree of V̇A/Q̇ mismatching. Thus patients with a high cardiac output can have little hypoxemi in the face of severe V̇A/Q̇ mismatching, while patients with inadequate cardiac output can have moderately severe hypoxemia with relatively little V̇A/Q̇ mismatching. In other words, the arterial PO2 alone cannot indicate the severity of V̇A/Q̇ mismatch in any given situation. Another generalization that can be made is that in the obstructive diseases, evidence from our work suggests that it is obstruction due to mucus secretions and/or airway edema and inflammation that is important in causing areas of low V̇A/Q̇ to be present. Bron‐choconstriction on the other hand, is less likely to be responsible for abnormal gas exchange, even while it is the more important factor in terms of airflow rates and symptoms. Finally, the data we have obtained, particularly in obstructive lung diseases, suggests that collateral ventilation is an important phenomenon that protects the lung from collapse and helps to maintain arterial PO2 in the face of severe airways obstruction. Administration of 100% oxygen did not significantly change V̇A/Q̇ relationships in any of these chronic lung diseases, indicating that at least in the patients that we studied, acute reversal of hypoxic vasoconstriction was not observed. This can be interpreted as evidence that hypoxic vasoconstriction is either not a major factor tending to preserve V̇A/Q̇ relationships in these patients, or if it is, it is not acutely reversible within one half hour of breathing 1002 oxygen.
NEW ASPECTS ON ATELECTASIS DURING ANAESTHESIA
Authors: Hedenstierna Göran , Brismar Bo , Strandberg Åke , Lundquist Hans , Tokics Leif
Published: April 2008

Sixteen subjects were studied with regard to lung tissue changes during general anaesthesia. The transverse area and the structure of the lung tissue were studied by computerized tomography. No abnormalities were noted in the lung tissue before anaesthesia, but within five minutes after induction, all subjects had developed crest‐shaped dependent changes of an increased density in both lungs. They correspond to 4 ‐ 5 per cent of the total transverse area. The size of the densities could not be correlated to the age of the subjects, or time of the anaesthesia, and they were not affected by the inspiratory oxygen fraction. They could be rotated by turning the patient, and the application of a positive end‐expiratory pressure eliminated or reduced the densities. It is suggested that the densities are atelectases, which develop by compression of lung tissue, and not by gas resorption.
Histamine‐induced asthma in children: effects on the ventilation‐perfusion relationship
Authors: Hedlin G. , Freyschuss U. , Hedenstierna G.
Published: April 2008

Summary. . Asthma was provoked by histamine inhalation in five children in order to study the hypoxaemia that might ensue and the underlying ventilation‐perfusion (V̇A/Q̇) mismatching. The distribution of the V̇A/Q̇ ratios was measured by a multiple inert gas technique before the provocation, during the asthmatic attack and after salbutamol inhalation. All children displayed a unimodal distribution of ventilation and perfusion under baseline conditions. During asthma they all developed a bimodal distribution, one mode lying within normal V̇A/Q̇regions but with increased perfusion to regions with V̇A/Q̇ ratios of OT‐1, which correlated with the observed hypoxaemia; the other mode was centred on a V̇A/Q̇ ratio of approximately 10 and the magnitude of this mode correlated with FEV1 in per cent of the predicted value. Salbutamol improved the V̇A/Q̇ distribution and restored the blood gases to normal. We hypothesize that histamine‐induced asthma causes a state of hyperinflation which compromises regional ventilation and blood flow, resulting in a V̇A/Q̇ mismatching with one normal and one high V̇A/Q̇ mode, and hypoxaemia.
Substantial effect of acute hydration on blood pressure in patients with autonomic failure
Authors: Mehlsen J. , Boesen F.
Published: April 2008

Summary. The effect of acute hydration on arterial blood pressure levels was investigated in ten patients with severe postural hypotension due to autonomic failure. Blood pressure and heart rate were determined in the supine and 60‐degree head‐up tilted position. Plasma volume and left ventricular ejection fraction were measured in the supine position. Measurements were repeated after rapid infusion of 11 of isotonic saline. Acute hydration resulted in increased supine mean blood pressure levels (P<0·01) despite normal plasma volumes in all patients. The postural reductions in mean blood pressure were reduced from 40 mmHg before to 20 mmHg after saline (median values, P<0·01). The results indicate that normal plasma volumes do not ensure optimal circulatory status in patients with autonomic failure. Acute hydration with isotonic saline may be used for immediate corrections of blood pressure levels in patients with autonomic failure and the response to acute hydration may be used as an indicator of the circulatory status in these patients.
Effect of β1‐adrenoceptor blockade on plasma levels of atrial natriuretic peptide during exercise in normal man
Authors: Thamsborg G. , Sykulski R. , Larsen J. , Storm T. , Keller. N.
Published: April 2008

Summary. Increased plasma levels of atrial natriuretic peptide (ANP) during exercise have been reported. To investigate the role of tachycardia as a stimulus for release of ANP during exercise the following study was undertaken. Graded exercise was performed in six healthy volunteers before and after β1‐adrenoceptor blockade. Plasma levels of ANP were determined at different workloads in both cases. At rest and at all workloads during exercise plasma levels of ANP were higher after β1‐adrenoceptor blockade than without. Therefore, it is unlikely that tachycardia is a major stimulus for secretion of ANP during exercise. It is suggested that increased right atrial pressure and/or pulmonary arterial blood pressure and increased plasma levels of catecholamines are important secretory stimuli for ANP during exercise.
Diurnal blood pressure profiles and variability in normotensive ambulant subjects
Authors: Turjanmaa V. , Kalli S. , Majahalme S. , Saranummi N. , Uusitalo A.
Published: April 2008

Summary. The 24‐hour variability in blood pressure and heart rate of 14 normotensive subjects was examined under ambulatory conditions with a continuous, invasive method. The results were analysed with 30‐second means calculated from beat‐to‐beat values. The registered time series had three different types of variation: (1) a continuous, fast variation around the mean level; (2) a stepwise, permanent change to a new level; and (3) a slow, continuous rise or fall. Variability in blood pressure and heart rate was determined by the 80 percent range of variation calculated from the cumulative distribution as the difference between the 90th and 10th percentiles. The variability in blood pressure and heart rate was significantly greater during waking hours than during night‐time. Variability followed a similar type of diurnal profile as the mean level. However, variability of diastolic pressure changed to a lesser extent than that of systolic pressure. Total 24‐hour variability was on average 45 mmHg in systolic blood pressure, 24 mmHg in diastolic pressure and 40 b.p.m. in heart rate. Using night‐time to describe the basal state, physical and mental activities in the evening and during daytime were found to raise variability in systolic pressure with 66%, diastolic with 8–16% and heart rate with 130–180%, respectively. The results show that in normotensive subjects the sleep‐wake state and activity are the major factors that affect both the diurnal profile and the variability in blood pressure and heart rate.
Umbilical artery reactivity and ultrastructural changes in pregnancy‐induced hypertension and other complicated pregnancies
Authors: Johnstone F. D. , Ugaily‐Thulesius L. , Thulesius O. , Nasrat A. N.
Published: April 2008

Summary. Abnormal pressor responses are known to occur in the maternal circulation in pregnancy‐induced hypertension (PIH), but little is know of the response of the foetal circulation. The responsiveness of umbilical arteries in PIH can be studied after delivery, and this is a useful model to explore the pathophysiological mechanisms involved.

In the present experiments, the in vitro response of umbilical artery rings to bradykinin and 5‐hydroxytryptamine (5‐HT) was tested and ultrastructural changes investigated. Umbilical arteries from 48 cords were studied. Fifteen of the mothers had PIH, five had essential hypertension pre‐dating the pregnancy and five had diabetes. Twenty‐three women had pregnancies uncomplicated by hypertension or serious medical or obstetric problems and these served as controls. Umbilical arteries from the severe proteinuric PIH group were significantly more responsive to 5‐HT as assessed by affinity constants (P <0·05). The responsiveness of arteries from all other groups did not differ from the normal cases. A probable mechanism for the findings is endothelial damage as a result of pre‐eclamptic disease. This was substantiated by ultrastructural evidence.
Respiratory sinus arrhythmia and carotid baroreflex control of heart rate in endurance athletes and untrained controls
Authors: Reiling M. J. , Seals D. R.
Published: April 2008

Summary. The purpose of this study was to compare the magnitude of the respiratory sinus arrhythmia, an index of cardiac vagal tone, and carotid baroreflex control of heart rate in endurance‐trained athletes (n= 12, aged 20 ± 1 years, X̄±SE) and untrained control subjects (n= 12, aged 22 ± 1 year). Average R‐R interval (ECG) and its variability were determined at rest under controlled breathing conditions, and the changes in R‐R interval in response to brief applications of suction (‐10, ‐25, ‐40 mmHg) and pressure (10 and 30 mmHg) to the carotid sinus region of the neck were also measured. The average R‐R interval at rest was greater in the athletes vs. controls (1150 ± 45 vs. 854 ±44 ms, P<0·001), but the standard deviation of the R‐R intervals was similar in the two groups (72 ± 15 vs. 70 ± 9 ms). The magnitude of the tachycardia in response to neck pressure was also similar in the athletes and controls. Although the heart rate responses to neck suction were not significantly different between the two groups, there was a strong trend for attenuated bradycardic responses in the athletes at the two highest stimulus levels (70 ± 14 vs. 97 ± 25 ms and 86 ± 14 vs. 145 ± 38 ms for the ‐25 and ‐40 mmHg levels, respectively, P>0·1). The results of this study do not support the postulate that cardiac vagal tone is enhanced in the endurance‐trained state. Furthermore, our findings indicate that arterial baroreflex control of heart rate during modest decreases in carotid sinus transmural pressure is not altered in endurance athletes; however, the magnitude of the reflex bradycardia in response to increases in carotid sinus pressure might be attenuated in these highly trained men.
Continuous and stepwise cystometry through suprapubic catheters—effect of infusion pattern and infusion rate on the cystometrogram of the normal human bladder
Authors: Andersson S. , Bjerle P. , Hentschel J. , Kronström A. , Niklasson U.
Published: April 2008

Summary. Continuous cystometry at two filling rates (50 and 100 ml min‐1) and stepwise cystometry (successive rapid volume infusions followed by bladder wall relaxation) were performed in 12 healthy subjects. Suprapubic catheters were used for infusion and recording of perivesical and intravesical pressures. The continuous cystometrograms obtained at filling rates of 50 and 100 ml min‐1, respectively, did not differ with respect to desire to void, transmural pressure increase or bladder capacity. Stepwise cystometry allowed the bladders to be filled to a slightly larger volume than during continuous cystometry, but with comparatively lower transmural pressures only at very large distension of the bladder. There was considerable inter‐individual variation in transmural pressure at both continuous and stepwise cystometry. Stepwise cystometry did not appear to provide any important additional information about pressure‐volume relationship in the normal human bladder than could be obtained at routine clinical cystometry.
A modified method of curve analysis in foot volumetry and its reference values
Authors: Brudin L. H. , Landgren I. M. , Bengtsson M. , Ohlin P.
Published: April 2008

Summary. Foot volumetry was introduced by Norgren & Thulesius in 1973 as a noninvasive method of functional evaluation of venous insufficiency. In the following paper we suggest a slightly different method of curve analysis, thus showing the possibility of reducing the methodological error by 30–40%. Based on healthy men and women between 15 and 75 years, new reference values are presented.
Hypotension induced by central hypovolaemia and hypoxaemia
Authors: Rowell L. B. , Blackmon J. R.
Published: April 2008

Summary. Our question was whether the reduced orthostatic tolerance that accompanies hypoxaemia in some (not all) subjects might be associated with an abnormally large release of adrenaline. Eight normal young men were exposed to lower body negative pressure (LBNP) at —30 to —40 mmHg while breathing air or 10% O2 in N2. Four subjects developed hypotension and bradycardia whenever LBNP was applied during hypoxaemia; four showed a rise in heart rate and stable blood pressure. During normoxia plasma adrenaline concentration did not rise during LBNP in any subject, nor during hypoxaemia plus LBNP in the subjects who remained normotensive. In the four men whose heart rates and blood pressures fell during LBNP with hypoxaemia, adrenaline rose markedly, reaching 200–1600 pg ml‐1. All subjects showed similar elevations in noradrenaline concentration during LBNP in both normoxia and hypoxaemia. The results suggest that reduced tolerance to central hypovolaemia during hypoxaemia could stem from known vasomotor and cardiac effects attending high plasma concentrations of adrenaline.
Determination of blood pressure level and changes in physiological situations: comparison of the standard cuff method with direct intra‐arterial recording
Authors: Turjanmaa V.
Published: April 2008

Summary.Blood pressure changes during a test series (sitting, supine, standing, bicycle ergometer test, recovery) were determined in a group of normotensive and borderline hypertensive subjects simultaneously with the continuous intra‐arterial registration (Oxford method) and the indirect cuff methods. The mean method difference between the direct and indirect method varied considerably in tests, from –2·3 to 12·9 mmHg in systolic pressure and from –4·3 to 18·2 mmHg in diastolic pressure. There was also a large scatter in the method difference between subjects. Analysis of the blood pressure responses to the other tests using values measured in the sitting position as the reference also revealed considerable variation between the methods. The accuracy of the indirect method was also tested by classifying the population in two subgroups along the median (high/low group) in all tests by each method. The classification discrepancy between the methods varied from 9 to 33% in systolic pressure and from 0 to 25% in diastolic pressure. The results indicate that the data gathered using the indirect measuring method from the arterial blood pressure level and changes in varying physiological conditions may differ considerably from direct intra‐arterial readings. On the other hand, the repeatability of the indirect method in stabile conditions was found to be acceptable indicating that the indirect method is useful in blood pressure follow‐up.
Arm and ankle blood pressure response to treadmill exercise in normal people
Authors: Engvall J. , Nylander E. , Wranne B.
Published: April 2008

Summary. Ninteen healthy volunteers, 10 men and nine women (mean age 38 and 30 years), exercised on a treadmill. The systolic blood pressure (BP) was measured at the ankle and in the arm after submaximal (8 min with a final load of 2 W kg‐1 body weight) and maximal exercise. The BP was measured for 10 min after exercise, or until the elimination of a negative pressure difference between ankle and arm. The pre‐study resting systolic arm and ankle pressures were 122 ± 11 and 144 ± 13 mmHg. One minute after submaximal exercise, arm and ankle BP were 147 ± 18 and 159 ± 19 mmHg (ankle‐arm pressure difference 12 ± 13 mmHg); 1 min after maximal exercise the corresponding figures were 182 ± 26 and 153 ± 35 mmHg (ankle‐arm pressure difference ‐29 ± 33 mmHg). We conclude that maximal exercise, but not an appropriately chosen submaximal exercise level, causes a negative BP difference between ankle and arm in normal people.
Non‐invasive evaluation of the conduit function and the buffering function of large arteries in man
Authors: Demolis P. D. , Asmar R. G. , Levy B. I. , Safar M. E.
Published: April 2008

The purpose of this study was to validate a two‐dimensional (2D) echography coupled range‐gated Doppler system for the non‐invasive measurement of internal diameter, blood flow velocity, and pulse wave velocity of peripheral arteries, such as the common carotid artery (CCA), femoral artery (FA), and brachial artery (BA) in man. The array of the ultrasonic system and the Doppler probe were attached and formed a fixed angle (38deg; 30′). The artery was firstly visualized using the echo‐graphic array probe in order to position the Doppler beam. Then, the range‐gated Doppler system was used to measure both internal diameter and blood flow velocity with the sample volume position covering the internal diameter. Using a hydraulic device, there was an obvious correlation between the calculated and the measured velocities (r = 0·98). Normal values of diameter, blood flow velocity and blood flow were measured in 18 healthy volunteers. The means (± 1 standard deviation) was as follows: diameter, CCA = 0·636 ± 0·027 cm, FA = 0·843 ± 0·074 cm, BA = 0·302 ± 0·052 cm; flow velocity, CCA = 19·5 ± 2·1 cm s1, FA = 11·4 ± 1·2 cm s1, BA = 6·7 ± 1·0 cm s1. Blood flows were as follows: CCA, 370·6 ± 42·5 ml mn1, FA 387·0 ± 75·0 ml mn1 and BA (wrist occlusion) 29·8 ± 12·5 ml mn1. The intra‐observer reproducibilities for CCA, FA and BA were respectively: for diameter, 4·9%, 4·12% and 14·8%; for velocity, 8·9%, 10·6% and 10·2%. The inter‐observer reproducibilities were respectively: for diameter, 5·6%, 5·4% and 11·3% for velocity, 6·5%, 5·7% and 6·3%. Simultaneous determinations of pulse wave velocity from blood flow velocity recording allowed estimations of the distensibility of these arteries. Finally, the coupled echo and range‐gated Doppler system permitted non‐invasive evaluation of blood flow calculated as the product of the vessel cross‐sectional area and measured blood velocity and also of arterial compliance as the ratio of the cross‐sectional area and the square of pulse wave velocity. Such estimations of the conduit and buffering functions of peripheral large arteries in man were shown to be more accurate for the common carotid and the femoral arteries than for the brachial artery.
Oscillatory contractions in vertebral arteries from hypertensive subjects
Authors: Webb R. Clinton , Schreur Kevin D. , Papadopoulos Stephen M.
Published: April 2008

Summary. In response to several agonists, tail arteries from spontaneously hypertensive stroke prone rats (SHRSP) contract in an oscillatory manner not observed in tail arteries from normotensive rats. This study evaluated whether oscillations in force development characterize the contractile pattern of vertebral arteries from hypertensive humans. Vertebral arteries were isolated and studied within 18–24 h post mortem. Helical strips of the arteries were mounted in a muscle bath for isometric force recording. Contractile responses to serotonin (10‐7M) and endothelin (10‐8M) in arteries from hypertensive subjects were characterized by fluctuations in force development whereas those in arteries from normotensive subjects usually remained constant with time. The frequency of the response was approximately 1–2 contraction/relaxation cycles per min. This pattern of oscillatory contractile activity was observed in all but one of the hypertensive arteries (n= 15), and in approximately 40% of the normotensive arteries (n= 12). Oscillatory activity was converted to maintained contraction by nifedipine (10‐7M) which also caused relaxation of the contractile response. Relaxation to acetylcholine (10‐6M) and nitroglycerin (10‐6M) did not alter the oscillatory contractions. Endothelium removal did not influence the oscillatory pattern of contraction. These observations suggest that oscillatory contractile activity in vertebral arteries from hypertensive subjects is related to abnormal calcium entry into the smooth muscle cells. This altered membrane property may contribute to changes in vascular reactivity in hypertension.
Is the high lactate release during arm exercise due to a low training status?
Authors: Jensen‐Urstad M. , Ahlborg G.
Published: April 2008

Summary To determine whether arm lactate release during arm exercise is related to the training status of the arms, seven arm‐trained athletes were studied during 30 min of continuous arm exercise (AE) or leg exercise (LE) of increasing intensities corresponding to 30%, 50%, and 80% of peak VO2 during AE and LE respectively. Blood vessels were catheterized for determination of regional blood flows and substrate exchanges. The respiratory exchange ratio was higher during AE than LE (P<0.01). The arteriovenous oxygen difference, [(A‐V)O2], for the leg during LE was 11–19% higher than the (A‐V)O2 for the arm during AE (P<0.01). At the highest intensity the (A‐V)O2 was 170±6 ml O21‐1 during LE, vs. 143 ± 9 during AE (P<0.01). Arm blood flow in relation to limb volume was 56–95% higher during AE (P<0.05). Arterial lactate concentrations were 27–60% higher during AE (P<0.01) and lactate release from the exercising limb was 2–4 times higher (P<0.05) during AE compared to LE. Adrenaline and noradrenaline rose 6‐ and 21‐fold, respectively, during AE and did not differ from corresponding LE values. During AE the (A‐V)O2 difference across the arm, arterial lactate concentration, and arm lactate release were of the same magnitude in arm‐trained and relatively less arm‐trained subjects. Lactate release in relation to O2 uptake by the exercising limb was 7–37% lower during AE in arm‐trained subjects compared to AE in arm‐untrained subjects but was 3–6 times higher than the corresponding relation during LE (P<0.01). We conclude that AE is associated with a larger lactate release compared to LE. This difference is only to a minor extent influenced by intense training of the arms. The high arm vs. leg lactate release appears to be associated with differences in regional circulatory adaptation by the exercising limb.
Critical evaluation of the ‘heated‐hand‐technique’ for obtaining ‘arterialized’ venous blood: incomplete arterialization and alterations in glucagon responses
Authors: Nauck M. A. , Ließ H. , Siegel E. G. , Niedmann P. D. , Creutzfeldt W.
Published: April 2008

Summary. In order to test the degree of ‘arterialization’ and the occurrence of arterio‐(or capillary‐) venous differences in glucose concentrations for commonly used blood sampling sites (including the retrogradely cannulated dorsal hand vein with application of dry heat to this hand/arm – the ‘heated‐hand‐technique’), oxygen partial pressure (oxygen saturation) and plasma glucose was determined in blood drawn from different venous sites before and after an oral glucose load (75 g). Experiments with and without heating (hot air 68°C) were compared in nine healthy volunteers. Basal pO2 (and oxygen saturation) increased in the order cubital fossa vein < superficial forearm vein < dorsal hand vein. Heating raised pO2 by ˜20 mmHg; P=0.008) and oxygen saturation (P= 0.008–0.02) at all sites, including those on the contralateral arm. Capillary‐venous glucose differences after the glucose challenge were significantly related to the sampling site (P< 0.0001). They were reduced by ˜50% in response to heat exposure (P=0.008–0.011) and could be correlated to pO2‐values (r=0.92; P= 0.01). The lowest capillary‐venous glucose concentration difference was measured with the ‘heated‐hand‐technique’ (0.4 ± 0.1 mmol l‐1). Heating did not alter integrated incremental glucose (capillary values), insulin, and C‐peptide‐responses and late, counter‐regulatory responses (120–240 min after glucose) of Cortisol, growth hormone, and adrenalin. However, the late glucagon response was enhanced (P=0.011) by heating, concomitant with a significantly reduced ‘reactive’ decrement in glucose concentrations. In conclusion, the ‘heated‐hand‐technique’ provides blood more similar to arterial blood that can be obtained from other venous sampling sites. However, significant residual differences in pO2 and glucose concentrations remain. In addition, altered counter‐regulatory hormone responses may occur with heating.
Plasma exudation and solute absorption across the airway mucosa
Authors: Greiff L. , Erjefäl I. , Svensson C. , Wollmer P. , Alkner U. , Andersson M. , Persson C. G. A.
Published: April 2008

Summary. The airway mucosa responds to inflammatory provocations with bulk exudation of plasma into the airway tissue (vascular exudation) and lumen (mucosal exudation). The intensity and time course of the exudative response can be relevantly examined by sampling and analysing airway surface liquids, because the luminal entry of plasma proteins/tracers promptly and quantitatively reflects the exudative response of the airways. The process of mucosal exudation of plasma is a prominent feature of airway inflammation and has been demonstrated in rhinitis, asthma, and bronchitis. Inflammatory mediators and allergen produce mucosal exudation of plasma into the airway lumen (outward permeability) whereas the solute absorption across the mucosa (inward permeability) is unaffected. Hence, in contrast to current views, we have demonstrated that in airway inflammation the solute absorption across the airway mucosa is not increased. The findings suggest the plasma exudation response also as a first line respiratory mucosal defence, allowing potent plasma protein systems to appear on an airway mucosa functionally intact as a barrier toward undue luminal material. Our data on plasma exudation and solute absorption across the mucosa of upper and lower airways further suggest the human nasal airways as a model relevant also for the tracheobronchial airways.
Stress hormones alter the pattern of free amino acids in human skeletal muscle
Authors: Wernerman J. , Hammarqvist F. , Botta D. , Vinars E.
Published: April 2008

Summary. Stress hormones were infused for 6 h in healthy volunteers (n= 32). Free amino acid concentrations were determined in plasma and in skeletal muscle biopsy specimens. A triple hormone combination of adrenaline, Cortisol, and glucagon raised the level of alanine in muscle, while glutamine, glutamate, the branched chain amino acids, the aromatic amino acids, and the basic amino acids decreased. Adrenaline alone partly reproduced this pattern, while a 6‐h infusion of Cortisol left the muscle free amino acids unaffected. In plasma all individual amino acids except alanine and glutamate decreased in the subjects receiving adrenaline or a triple‐hormone combination. Altered plasma amino acid concentrations did not necessarily reflect changes in the tissue amino acid content. It is concluded that an infusion of a triple combination of stress hormones into healthy volunteers produces changes in muscle amino acid metabolism similar to those seen immediately after surgical trauma.
Glucose‐induced thermogenesis in patients with small cell lung carcinoma. Before and after inhibition of tumour growth by chemotherapy
Authors: Simonsen L. , Bülow J. , Sengeløv H. , Madsen J. , Ovesen L.
Published: April 2008

Summary. Seven weight‐losing patients with histologically verified small cell lung carcinoma were given an oral glucose load of 75 g before and at least 3 weeks after the end of chemotherapy to examine the effect of glucose on whole body and skeletal muscle thermogenesis before and after reduction of tumour. Whole body energy expenditure was measured by the open circuit ventilated hood system. Forearm blood flow was measured by venous‐occlusion strain‐gauge plethysmography. The uptake of oxygen in skeletal muscle was calculated as the product of the forearm blood flow and the difference in a‐v oxygen concentration. Whole body resting energy expenditure (REE) did not increase, it was 4.4±0.3kJmin‐1(mean±SE) before chemotherapy and 4.4±0.2 kJ min‐1 after chemotherapy. The glucose‐induced thermogenesis in the 180 min following the glucose load was 93.6±9.9 kJ 180 min‐1 before chemotherapy. This is significantly increased compared to that found in a healthy control group (74.7±4.8 kJ 180 min‐1, P < 0.02). The glucose‐induced thermogenesis was significantly reduced to 47.7±10.2 kJ 180 min‐1 (P < 0.05) after chemotherapy. The oxygen uptake in resting skeletal muscles was 6.9±0.3 μmol 100 g‐1 min‐1 before chemotherapy and 7.0±0.7 μmOI 100 g‐1 min‐1 after chemotherapy. This did not increase during the first 90 min following the glucose load in either investigations. In the period 90–180 min following the glucose load, the oxygen uptake was significantly increased before chemotherapy as compared to after chemotherapy, which suggests that the reduced whole body thermogenesis after chemotherapy in part was due to reduced skeletal muscle thermogenesis.
Tachycardia and coronary blood flow: non‐invasive estimation during Valsalva manoeuvre and exercise
Authors: Ciccone M. , Federici A. , di Noia D. , Cipressa A. , Epifani M. , Rizzon P.
Published: April 2008

Summary. Simultaneous changes in cycle length and coronary blood flow were studied during Valsalva manoeuvre and supine cycloergometer exercise test in 10 male patients (mean age 4812 years) who had successfully undergone myocardial revascularization by surgical anastomosis of the left internal mammary artery on the left anterior descending coronary artery. Blood velocity curves in the left internal mammary artery were obtained by a non‐invasive continuous‐wave Doppler probe at rest, in the last phase of the expiratory effort of the Valsalva manoeuvre and at the maximum load attained during the exercise test. Mean arterial pressure by sphygmomanometer, and cardiac cycle length on the basis of Doppler recording were measured. Mean blood velocity, the length of the blood column entering the coronary bed at each cycle (cardiac cycle times mean velocity), an index of blood cell acceleration (the ratio of mean velocity to cardiac cycle), and an index of coronary resistance (the ratio of mean pressure to mean velocity), were calculated.

For approximately the same change in cycle length, coronary resistance decreased in exercise, with an increased mean velocity, but increased in Valsalva, with no changes in mean velocity. The length of the blood column entering the coronary bed at each cycle was unchanged in exercise, with a marked increase in the acceleration index, while it decreased in Valsalva.

Therefore, we hypothesize that tachycardia has a limiting effect on sympathetic coronary constriction in Valsalva when cardiac external work is decreased, and an additional vasodilatory effect on coronary bed in exercise when external work is increased.,
The mean frequency of the EMG of the knee extensors is torque dependent both in the unfatigued and the fatigued states
Authors: Gerdle B. , Karlsson S.
Published: April 2008

Summary. The present study aimed to investigate the shift in the mean frequency (fmean) of the power density spectrum of the electromyogram (EMG) during endurance tests of the knee extensors at three different torque levels (70% MVC, 25% MVC and 10% MVC). Fourteen clinically healthy men performed the three endurance tests until exhaustion. Surface EMG(s) were obtained from the vastus medialis, the vastus lateralis and the rectus femoris muscles and fmean and signal amplitude (RMS) were computed. The subjects rated the perception of fatigue in the knee extensor muscles throughout the three tests using a 10‐point graded scale.

The endurance time increased with decreasing torque level. A significantly higher perception of fatigue was found at the low torque level (10% MVC) at the end of the endurance time. Individual time series analysis (using linear regression) was performed. It was found that linear models described well the behaviour of fmean throughout the endurance time at the three torque levels. When the endurance times were normalized significant differences in the rate of decrease in fmean were found for vastus lateralis and rectus femoris; the rate decreased with decreasing torque level. For these two muscles significant differences were also found in fmean in the unfatigued state; at 10% MVC significantly lower fmean was found.

The present study demonstrated both that the unfatigued fmean and the rate of decrease in fmean (with normalized endurance time) were torque dependent. The latter finding, combined with our result that the subjective fatigue was highest at the lowest torque level, calls into question the use of fmean as a valid indicator of peripheral fatigue.