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Biomedical subjects

J Mehlsen

Publications and source records attributed to J Mehlsen.

At least 37 records · Page 2Linked to original sources
PubMed1997

A comparison of physical characteristics between patients seeking treatment for neck pain and age-matched healthy people.

OBJECTIVE: To compare physical characteristics of the cervical musculature, including maximal isometric strength of the flexors and extensors, relative isometric endurance of the extensors and the active range of motion (ROM) in extension in a group of patients seeking treatment for chronic neck pain and a group of age-matched healthy people. SETTING: Department of Medical Orthopedics, National University Hospital, Denmark. METHODS: One hundred and nineteen chronic neck-pain patients underwent physical testing for active ROM in extension, maximal isometric torque in extension and flexion and relative isometric endurance in extension before entering a clinical controlled trial studying the treatment of chronic neck pain. Their results were then compared with those of 80 age-matched healthy people. RESULTS: The reliability study demonstrated good within-day and day-to-day reproducibility for active ROM. Active ROM was significantly reduced in female patients, but not in all male age groups. Patients exhibited clinically and statistically significant reductions in maximal isometric torque in both the flexors and extensors of the cervical spine, with the greatest reduction seen in the extensor muscle group. Most patient groups demonstrated a significant reduction in relative isometric endurance of the extensors. CONCLUSIONS: In agreement with most low-back comparisons between patients and age-matched healthy people, the greatest relative muscular deficiencies seem to be in the extensor muscle group. Additionally, most patients exhibit a significant decrease in active ROM during extension. The clinical utility of physical measurements has not been firmly established.

Adult↗
PubMed1996

[The effect of Ginkgo biloba extract in patients with intermittent claudication].

Eighteen patients with stable intermittent claudication were randomized in a double blind cross-over study comparing the effects of the Ginkgo biloba extract GB-8 at a dose of 120 mg o.d. with placebo. All patients were treated for three months with the active extract and three months with placebo. The effects of treatment on arterial insufficiency were quantified by measurements of systemic and peripheral systolic blood pressures, and pain-free and maximal walking distances on a tread-mill. Questionnaires based on visual analogue scales were used to quantify the severity of leg pain, impairment of concentration, and inability to remember. Short-term memory was objectively assessed. We did not find any significant changes in either peripheral blood pressures, walking distances or the severity of leg pain. Systemic blood pressure was reduced both by placebo and GB-8. The impairment of concentration and the inability to remember were both reduced, when comparing results during active treatment to placebo. Short-term memory did not change significantly. In conclusion, our study has shown that treatment with the Ginkgo biloba extract GB-8 improves some cognitive functions in elderly patients with moderate arterial insufficiency, whereas the extract did not change signs and symptoms of vascular disease in the patients.

Aged↗
PubMed1996

ACE inhibition with spirapril improves diastolic function at rest independent of vasodilation during treatment with spirapril in mild to moderate hypertension.

The effects of the ACE inhibitor spirapril and of hydrochlorothiazide on left ventricular diastolic function were studied. Thirteen patients with mild to moderate essential hypertension completed this randomized, double-blinded, placebo-controlled, crossover study. After a three-week run-in period the patients entered three periods lasting four weeks each, wherein they were treated with placebo, spirapril, or hydrochlorothiazide. Blood pressure, hemodynamic variables (stroke volume, heart rate, cardiac output, index of contractility, and systemic vascular resistance), echocardiography (left ventricular mass), and Doppler-derived atrial to early (A/E)-ratio velocity time integrals (VTI) were measured at the end of each of the four periods. Spirapril lowered the A/E-ratio VTIs (0.57, 0.12-1.00) (P < 0.02) as compared with both placebo (0.80, 0.50-2.67) and hydrochlorothiazide (0.83, 0.44-1.25), and the drug normalized the A/E-ratio VTI in those patients with elevated values. The hemodynamic variables, left ventricular mass, and end-systolic wall stress were unchanged during all three treatments. There were no significant changes in mean blood pressure during the treatment periods. These results indicate that spirapril lowers A/E ratio within four weeks in patients with mild to moderate essential hypertension. It thereby seems able to improve left ventricular diastolic function. The effect is not dependent upon changes in hemodynamic variables, blood pressure, left ventricular mass, or end-systolic wall stress.

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PubMed1996

Effect of spirapril and hydrochlorothiazide on platelet function and euglobulin clot lysis time in patients with mild hypertension.

Thirteen patients with mild hypertension (untreated diastolic blood pressure of 95 to 114 mmHg) received, in random order, three successive treatments of four weeks with placebo, spirapril (6 mg daily), or hydrochlorothiazide (HCT2) (24 mg daily). At the end of each treatment, blood samples for assessment of platelet aggregation and platelet release of platelet factor 4 (PF4) and for assessment of fibrinolysis, estimated by tissue plasminogen activator (t-PA), plasminogen activator inhibitor-type 1 (PAI-1), and euglobulin clot lysis time (ECLT), were taken, first at rest, then immediately after five to ten minutes of vigorous exercise, and finally after the subsequent hour of recovery rest. Platelet aggregation induced in vitro by adrenaline significantly decreased during treatment with HCT2, the threshold rising to 10 microM as compared with 1.0 with placebo (P < 0.05) at rest, and the threshold for adenosine diphosphate (ADP) aggregation also rose, from 2 microM to 4 (NS). The resting plasma PF4 value fell, although not significantly, during HCT2 treatment from the placebo value of 3.28 to 2.56 ng/mL. During spirapril treatment there was no change in the threshold of either adrenaline or ADP for aggregation of platelets sampled at rest, and the PF4 plasma levels showed no significant reductions at rest. However, during exercise PF4 showed an approximate doubling of the resting value irrespective of therapy. This exercise-induced increase in PF4 was significantly reduced by spirapril as compared with placebo (P < 0.05). ECLT and t-PA did not shift significantly from the placebo level during either therapy. PAI-1 did not change during spirapril therapy, but during HCT2 treatment it fell, although not significantly, to 9.36 IU/mL from 15.91 with placebo (NS). Spirapril and HCT2 did not produce any unwanted side effect on platelet function or fibrinolysis. HCT2 seems to decrease platelet activity at rest, whereas spirapril seems to some extent to decrease platelet activity at exercise.

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PubMed1995

[Dependence of the arterial blood pressure on cardiac filling in severe orthostatic hypotension].

The present study aimed at an investigation of the relation between arterial blood pressure and cardiac filling in patients with severe postural hypotension. Seven patients aged 49 to 84 years were studied during head-up tilt at three different tilt angles (median values: 0, 25, and 45 degrees) using intraarterial blood pressure recordings and estimates of left ventricular volumes by radioisotope ventriculography. Mean arterial blood pressure was reduced from 105 mmHg (79-129) in the horizontal position to 97 mmHg (61-112) and 83 mmHg (36-93; p < 0.0001), respectively, in parallel with a reduction in left ventricular end-diastolic volume index from 59 ml m-2 (30-65) to 36 ml m-2 (23-44) and 22 ml m-2 (16-38; p < 0.001). Left ventricular contractility was high, and the postural reductions in cardiac output were unopposed by vasoconstriction. The study has demonstrated that blood pressure is strongly dependent upon cardiac filling in severe postural hypotension, and has underlined the importance of intravascular volume expansion as a measure against postural hypotension.

Aged↗
PubMed1995

The twitch interpolation technique for study of fatigue of human quadriceps muscle.

The aim of the study was to examine if the twitch interpolation technique could be used to objectively measure fatigue in the quadriceps muscle in subjects performing submaximally. The 'true' maximum isometric quadriceps torque was determined in 21 healthy subject using the twitch interpolation technique. Then an endurance test was performed in which the subjects made repeated isometric contractions at 50% of the 'true' maximum torque for 4 s, separated by 6 s rest periods. During the test, the force response to single electrical stimulation (twitch amplitude) was measured at 50% and 25% of the estimated maximum torque. In 10 subjects, the test was repeated 2-4 weeks later. Twitch amplitudes at 50% of maximum torque declined exponentially with time in 20 of 21 subjects. The distribution of the exponential rate constant was skewed with a mean of 4.6 h-1 and range of 0.3-21.5 h-1. After logarithmical transformation, the distribution of the exponential rate constant fitted closely to a normal distribution, and the inter-individual variation was SD = 1.15 compared to an intra-individual variation of 0.29. The coefficient of correlation for repeated determination was 0.91 (P < 0.001, n = 10). In conclusion, the twitch technique can be used for objectively measuring fatigue of the quadriceps muscle.

Adult↗
PubMed1995

Does calcium channel blockade and beta-adrenergic blockade affect platelet function and fibrinolysis to a varying degree?

The effects of isradipine and atenolol on platelet function and fibrinolytic activity were studied in 10 male patients with mild untreated hypertension. After a 2-week placebo run-in period, the volunteers were randomized to either isradipine 2.5 mg twice daily or atenolol 100 mg daily for a 6-month period. Those initially receiving isradipine then received atenolol and vice versa. After each therapy regimen, blood was drawn at rest and 1 h after exercise during a maximum exercise test. Platelet activity in vivo was estimated as release of B-TG and PF-4. Fibrinolytic activity was estimated as the fast-acting inhibitor against tissue plasminogen activator usually termed PAI-1. During atenolol and isradipine therapy, blood pressure (BP) was equally reduced (p < 0.05). Heart rate (HR) decreased during atenolol treatment but was not changed by isradipine. Platelet activity in vivo estimated as B-TG and PF-4 decreased irrespective of therapy (p < 0.02). During atenolol, as during placebo therapy, exercise resulted in a significant increase in platelet activity, as shown by an increase in B-TG (p < 0.02) and in PF-4 (p < 0.01). Such increase was not observed during isradipine treatment. Both treatments tended to improve fibrinolysis, as shown by a decrease in PAI, 1 h after exercise. Reducing BP with isradipine or atenolol results in a similar decrease in platelet activity and PAI-level, tested at rest and 1 h after rest, respectively. During exercise, platelet activity increased during atenolol treatment; such change did not occur during isradipine treatment.

Adult↗
PubMed1995

The pulsatility index and the resistive index in renal arteries in patients with hypertension and chronic renal failure.

BACKGROUND: The pulsatility index (PI) and the resistive index (RI) are used as pulsed-wave Doppler measurement of downstream renal artery resistance. Little information is available on their value in chronic renal failure and their correlation to parameters of renal function and haemodynamics. The aim was to compare PI and RI of renal arteries in healthy volunteers and in patients with hypertension and chronic renal failure, and furthermore to study the correlation of these indices to measurements of renal haemodynamics and function by standard methods in patients with renal failure and hypertension. METHODS: Twenty-five hypertensive patients (10 females, 15 males, mean age 52 years (24-74) with a glomerular filtration rate (GFR) less than 50 ml/min and an arterial blood pressure above 140 mmHg systolic and 95 mmHg diastolic were included in the study. Ten healthy, normotensive volunteers (4 females and 6 males, mean age 43 years (30-62)) served as controls in the Doppler examinations. Doppler examinations were performed in segmental arteries by an Acuson 128. The PI and the RI was calculated from the blood flow velocities. RESULTS: Both the PI and the RI were significantly higher in the patient group (P) than in the control group (C) (PI, P 1.65 (1.31-1.86), C 1.19 (0.93-1.25), P = 0.003; RI, P 0.76 (0.69-0.81), C 0.67 (0.64-0.70), P = 0.003). Both PI and RI correlated significantly with effective renal plasma flow (PI: r = -0.5, P = 0.02; RI: r = -0.5, P = 0.006), renal vascular resistance (PI: r = 0.4, P = 0.05; r = 0.5, P = 0.02), filtration fraction (PI: r = 0.6, P = 0.005; RI: r = 0.5, P = 0.01) and clearance of creatinine (PI: r = -0.6, P = 0.008; RI: r = -0.6, P = 0.006). Only RI correlated significantly to GFR (r = -0.5, P = 0.02). The indices did not correlate to serum creatinine, or mean arterial blood pressure. CONCLUSION: PI and RI seems to be closely related to parameters of renal haemodynamics and clearance of creatinine in patients with chronic renal failure and hypertension.

Adult↗
PubMed1994

[Padma-28, a herbal preparation, increases walking distance in patients with intermittent claudication].

Thirty-six patients with stable intermittent claudication were randomized in a doubleblind study either to treatment with two tablets of Padma-28 twice daily (containing 340 mg dried herbal mixture composed according to an ancient lamaistic prescription) or placebo for four months. Effect of treatment was quantified by measurements of systemic and peripheral systolic blood pressures, and pain-free and maximal walking distances on a tread-mill. The actively treated group attained a significant increase in pain-free walking distance from 115 m (72-218) to 227 m (73- >1000, p < 0.05). The placebo group did not show significant changes in either pain-free or maximal walking distance. Significant changes in systemic or peripheral blood pressures could not be demonstrated in any of the groups. In conclusion, our study has shown that treatment with Padma-28 over a four month period significantly increases the walking distance in patients with stable intermittent claudication of long duration.

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PubMed1994

[Positive effect of intermittent overpressure and underpressure (Vacusac) in intermittent claudication].

Twenty-two patients with intermittent claudication were included in a double-blinded, randomized trial comparing the effects of 25 treatments with intermittent suction and pressure (Vacusac treatment) to 25 placebo applications given over a period of two months. Twelve patients participated in an open trial investigating the effects of the same treatment on adenosine diphosphate (ADP)-induced platelet aggregation and fibrinolysis. Active treatment resulted in significant improvements in pain-free and maximal walking distances, whereas no changes could be found during placebo application. Active treatment caused significant increments in ADP-induced platelet aggregation, while the effects on fibrinolysis were uncertain. It is concluded that intermittent suction and pressure treatment offers a new approach for conservative treatment of intermittent claudication.

Aged↗
PubMed1994

Electrical impedance measured changes in thoracic fluid content during thoracentesis.

In patients (seven females and 11 males) with pleural effusion due to pulmonary (n = 13) or cardiac disease (n = 5) the change in baseline transthoracic impedance (Z0) was measured by electrical impedance (BoMed's NCCOM-3, 70 kHz) during thoracentesis. Data were obtained before and after withdrawal of each 500 ml, and at the end of the thoracentesis. We found a close linear correlation (r = 0.97) between changes in Z0 and the volume of aspirated pleural effusion (y = 0.415.x+0.093). The variability of the estimated thoracic fluid volumes was analysed with a plot of the residuals from the regression line, and we found that changes in thoracic fluid volume estimated by impedance technique would be within +/- 302 ml (= 2 SD). However, the absolute value of Z0 before thoracentesis could not differentiate the group of patients with pleural effusion from normal subjects (n = 28).

Aged↗
PubMed1994

Biochemical changes in relation to a maximal exercise test in patients with fibromyalgia.

Patients with fibromyalgia often complain of fatigue and pain during exercise and of worsening of pain days after exercise. The aim of the study described here was to determine if abnormal changes in potassium or lactate could be observed during an exercise test in fibromyalgia. Whether an abnormal incline in plasma creatine kinase or myoglobin could be observed days after the test was studied also. Fifteen female fibromyalgia patients and 15 age- and sex-matched controls performed a stepwise incremental maximal bicycle-ergometer test. Blood samples were collected from a catheter in a cubital vein. The changes in heart rate, potassium levels, and haematocrit during the exercise test were similar in the two groups. The maximal obtained lactate concentration was 4.2 mmol l-1 (3.5-5.6) in the patients as compared to 4.9 mmol l-1 (3.9-5.9) in the controls (NS). The estimated anaerobic threshold of 2 mmol l-1 was reached at a heart rate of 124 min-1 in the patients with fibromyalgia as compared to 140 min-1 in the controls (P = 0.02). In relation to workload, the patients scored higher on a Borg scale for perceived exertion during exercise, but if the Borg score was related to lactate no significant difference was found. The patients reported 86% and 79% of maximal pain in the thighs on the visual analogue scale 1 and 2 days after the test, but the creatine kinase and myoglobin concentrations were not increased.

Adult↗
PubMed1994

Effect of supine exercise on platelet aggregation and fibrinolytic activity.

In 12 healthy young men, strenuous cycling exercise in the supine position, caused platelet aggregability to decrease and the ADP threshold to rise from 7.0 microM resting, to 9.5 exercising (P < 0.01). At the same time, fibrinolytic activity increased markedly: euglobulin clot lysis time shortened from 178 to 68 min, PAI-1 fell from 8.91 to 5.16 IU ml-1, and t-PA rose from 0.56 to 3.95 IU ml-1, all three values were significant to P < 0.01. When the erect posture was assumed after lying at ease for 1 h after exercise, it did not increase platelet activity as expected, but caused a modest increase of fibrinolytic activity. These results suggest that supine exercise will not affect the haemostatic system adversely.

Adult↗
PubMed1994

Erythropoietin treatment does not compromise cardiovascular function in chronic renal failure.

The anemia in patients with chronic renal failure can be corrected through treatment with recombinant human erythropoietin treatment. This correction is associated with changes in the rheologic variables, which could explain the changes in hemodynamics found by many investigators. The authors have followed up 11 patients with chronic renal failure on hemodialysis before and during six months of therapy with erythropoietin. The measurements were made before treatment, after four months of therapy, and after six months of therapy. The measurements included hematocrit, osmotic resistance of the red blood cells, red blood cell volume, plasma volume, heart rate, arterial blood pressure, and cardiac output measured by the indicator dilution method. They found a significant increase in hematocrit hemoglobin, and red blood cell volume and a decrease in osmotic resistance while the hemodynamic variables were unchanged. The conclude that, in spite of changes in rheologic variables, increasing viscosity of the blood and thus possibly increasing the peripheral resistance, these had no effect on the cardiovascular state. Erythropoietin treatment improves the subjective well-being in patients on chronic hemodialysis without compromising their cardiovascular function.

Adult↗
PubMed1994

Dependency of blood pressure upon cardiac filling in patients with severe postural hypotension.

Autonomic denervation of the vascular bed results theoretically in a stronger dependency of blood pressure upon intravascular volume, and the study described aimed at an investigation of the relation between cardiac filling and arterial blood pressure in patients with severe postural hypotension. Seven patients were studied during head-up tilt at three different tilt angles using intra-arterial blood pressure recordings and estimates of left ventricular volumes by radioisotope ventriculography. Blood pressure fell dramatically during head-up tilt due to reductions in cardiac output unopposed by vasoconstriction. The reduction in cardiac output resulted from reductions in left ventricular end-diastolic volumes with unchanged left ventricular ejection fractions and only moderate increments in heart rate. The study was demonstrated that blood pressure is strongly dependent upon cardiac filling in severe autonomic dysfunction, and that volume expansion is an important measure against postural hypotension.

Aged↗
PubMed1994

The effect of erythropoietin on platelet function and fibrinolysis in chronic renal failure.

The influence of erythropoietin therapy on platelet function and fibrinolysis was evaluated in 12 anemic hemodialysis patients. Six months of therapy with human erythropoietin (50 to 80 IU/kg initially) raised the hemoglobin level to 10.8 g/dl but did not increase platelet activity in vivo as measured by beta-thromboglobulin or platelet factor 4. There was no change in the platelet aggregation thresholds in vitro for ADP, adrenaline, thrombin or collagen during treatment. Platelet number and volume were also unaffected. Fibrinolytic activity intensified as erythropoietin treatment proceeded, with a fall of euglobulin clot lysis time and rise in the activity of t-PA. PAI-1 levels also showed a downward trend, without reaching significance. Thus erythropoietin treatment in modest doses does not seem to adversely influence the hemostatic system in patients on hemodialysis.

Adult↗
PubMed1993

[Systolic blood pressure at rest and during submaximal and maximal exercise on ergometer bicycle. The value of automatic and auscultatory determination].

Fifteen normal subjects participated in this comparison of systolic blood pressure measurement determined both automatically (AU) with the Kivex Ergometrics 900 and by the standard auscultatorically method (AM). Maximal exercise, was achieved by work performed on an electronically braked ergometer bicycle. In the first part of this study, simultaneous measurements of systolic blood pressure were made by the Kivex device and by the standard method at rest, every minute during exercise, and one minute after stopping exercise. The differences (two standard deviations) between AU and AM (n = 229) were +/- 19 mmHg at rest, +/- 15 mmHg at submaximal level, and +/- 49 mmHg at maximal exercise level. The acceptable difference was determined to +/- 15 mmHg by Bland and Altman. In the second part of this study, the differences between simultaneously measured auscultatoric systolic blood pressure by two observers (n = 205) was +/- 10 mmHg at rest, +/- 9 mmHg at submaximal level, and +/- 10 mmHg at the maximal exercise level. It can therefore be concluded that Kivex automatic blood pressure device, Ergometrics 900, is unable to measure accurately systolic blood pressure with sufficient agreement in normal subjects at the maximal stress level or at rest. However, at the submaximal exercise level, the Kivex device was able to measure systolic blood pressure with an acceptable agreement with the standard method. Therefore, the blood pressure results obtained by the Kivex device are highly influenced by the exercise level. The agreement between two observers using standard auscultatory method for systolic blood pressure measurement was found to be acceptable at all levels of exercise.

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