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Biomedical subjects

J R Petersen

Publications and source records attributed to J R Petersen.

At least 19 recordsLinked to original sources
PubMed1997

[Thyroid stimulating antibodies in pregnant women with Graves' disease and neonatal thyrotoxicosis].

Thyroid stimulating antibodies (TSAb) are thought to be involved in the initiation of Graves' disease, and thyrotoxicosis in the neonatal period is often caused by TSAb passing the placental barrier. We wanted to evaluate measurement of TSAb levels as a possible predictor of neonatal thyrotoxicosis in pregnant patients with Graves' disease. We retrospectively evaluated 18 consecutive pregnant patients with Graves' disease. In 16 patients TSAb were measured in early pregnancy, six had increased values. In 14 of 18 patients normal values were found in late pregnancy and none of the children developed neonatal thyrotoxicosis. Two patients had greatly elevated TSAb values, and their children had neonatal thyrotoxicosis. Two patients had slightly elevated TSAb levels and delivered normal children. We conclude that all pregnant patients with an actual or a history of Graves' disease, should have measured TSAb. High TSAb values in late pregnancy indicate a considerable risk of neonatal thyrotoxicosis.

Adult↗
PubMed1997

The pulsatility index and the resistive index in renal arteries. Associations with long-term progression in chronic renal failure.

BACKGROUND: The pulsatility index (PI) and the resistive index (RI) are used as pulsed-wave Doppler measurements of downstream renal artery resistance. PI and RI have been found to correlate with renal vascular resistance, filtration fraction and effective renal plasma flow in chronic renal failure. The aim of the present study was to evaluate the potential relationship between these indices and the rate of decline in renal function, as reflected by changes in different parameters of renal function in patients with chronic renal failure. METHODS: Twenty-one patients (8 females; 13 males, mean age 58 years (36-75)) with chronic renal failure were enrolled in the study. Doppler examinations were performed in the segmental arteries by an Acuson 128XP. The PI and the RI was calculated from the blood flow velocities. Parameters of renal function were measured every 3 1/2 months, and all patients were followed for 18-21 months. Progression of renal dysfunction was estimated by linear regression of parameters of renal function versus time. RESULTS: In a multiple regression analysis both PI and RI correlated significantly to the rate of decline in reciprocal serum creatinine (PI: r = -0.48, P = 0.03; RI: r = -0.52, P = 0.02). Furthermore, when separating the patients in two groups by the median RI value, there was a significant difference between the groups in rate of decline in reciprocal serum creatinine (P = 0.02). For PI this distinction was also present (P = 0.04). CONCLUSION: PI and RI correlated to the severity of the renal disease, as reflected by the rate of decline in reciprocal serum creatinine during antihypertensive treatment. The median RI or PI value could separate the patients into groups one of slow and another of fast progression.

Adult↗
PubMed1996

Laser induced resonance energy transfer--a novel approach towards achieving high sensitivity in capillary electrophoresis. I. Clinical diagnostic application.

Most of the procedures currently performed by capillary zone electrophoresis (CZE) with laser induced fluorescence detection requires prior derivatization. This increases cost, the turn-around-time and chances of extraneous contaminations. CZE with laser induced resonance energy transfer is demonstrated as a viable alternative for detecting non-fluorescent compounds with no prior derivatization. The feasibility of this approach is demonstrated by separating and directly detecting salicylic acid (2,4-dihydroxybenzoic acid), gentisic acid (o-methoxybenzoic acid), salicyluric acid (o-hydroxyhippuric acid) and 4-aminosalicylic acid in urine. The detection of salicylate in serum is also shown. The method is highly sensitive with detection limits in the 1.10(-7) M range. Importantly it requires no prior preconcentration or sample preparation and can be used with complex sample matrices such as serum and urine.

Aminosalicylic Acid↗
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.

Aged↗
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.

Aged↗
PubMed1996

MR velocity mapping measurement of renal artery blood flow in patients with impaired kidney function.

Renal blood flow (RBF) was measured in 9 patients with chronic impaired kidney function using MR velocity mapping and compared to PAH clearance and 99mTc-DTPA scintigraphy. An image plane suitable for flow measurement perpendicular to the renal arteries was chosen from 2-dimensional MR angiography. MR velocity mapping was performed in both renal arteries using an ECG-triggered gradient echo pulse sequence previously validated in normal volunteers. Effective renal plasma flow was calculated from the clearance rate of PAH during constant infusion and the split of renal function was evaluated by 99mTc-DTPA scintigraphy. A reduction of RBF was found, and there was a significant correlation between PAH clearance multiplied by 1/(1-hematocrit) and RBF determined by MR velocity mapping. Furthermore, a significant correlation between the distribution of renal function and the percent distribution of RBF was found.

Aged↗
PubMed1995

Micellar electrokinetic capillary chromatographic separation of steroids in urine by trioctylphosphine oxide and cationic surfactant.

Separation of the six structurally similar and hydrophobic neutral steroids, testosterone, dimethyltestosterone, testosterone propionate, cortisone, hydrocortisone and 17-deoxycorticosterone, was achieved by hydrophobic micellar electrokinetic chromatography. A triphasic separation involving micellar dodecyltrimethylammonium bromide (DTAB), a dynamic bilayer formed due to electrostatic interaction between the silica surface and DTAB, and aqueous phase is proposed to account for the observed separation of the steroids. The running buffer consisted of 0.05 M DTAB and 0.0052 M trioctylphosphine oxide in 0.01 M of phosphate buffer pH 7.4. A detection limit of 500 ng/ml was achieved for each steroid and the application of the method to urine samples is described.

Chromatography↗
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.

Aged↗
PubMed1994

[No grounds for vasodilatory treatment in pulmonary hypertension].

Large scale review of the literature on vasodilatory treatment of secondary pulmonary hypertension reveals an abundance of non-controlled and non-blinded studies. There is only a handful of randomized, placebo-controlled trials. These few studies cannot support the findings from non-controlled studies showing beneficial haemodynamic effects. Only two controlled studies showed clinically relevant parameters such as working capacity, mortality and morbidity, and vasodilators do not seem to possess beneficial influence on these parameters. It is concluded, that until now no publication has been able to convincingly demonstrate any long-term clinically beneficial effects of vasodilators in patients with secondary pulmonary hypertension.

Humans↗
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↗
PubMed1993

[Severe obstructive lung disease. The effect of the calcium antagonist isradipine on working capacity, pulmonary function, morbidity and survival].

Several studies have reported beneficial haemodynamic effects of calcium antagonists in the treatment of patients with chronic obstructive pulmonary disease (COPD) and pulmonary hypertension. Such effects include a decrease in pulmonary vascular resistance, an increase in cardiac output, and an increase in oxygen delivery, but the clinical implications of these effects remain uncertain. We therefore designed this first randomized, double-blind, placebo-controlled, long-term study to investigate the clinical effects of a calcium antagonist (isradipine) on patients with COPD. The aim of the study was to investigate the hypotheses that isradipine was able to increase working capacity and lung function, and decrease morbidity and mortality. During a 22-month observation of 52 patients with severe COPD no statistically significant differences between the isradipine group and the placebo group were found with regard to these parameters. It is concluded that the existing evidence does not justify the introduction of calcium antagonists as part of the routine treatment of COPD with pulmonary hypertension.

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.

Adult↗
PubMed1993

Clinical validation of an RIA for natural and recombinant erythropoietin in serum and plasma.

A sensitive radioimmunoassay (RIA) for the detection of erythropoietin (EPO) was developed using antibody directed against EPO from human urine. With 100 microL of sample, the assay is sensitive to 7 U/L, well below the mean EPO level in normal males (15.1 +/- 3.5 U/L) or females (15.4 +/- 4.8 U/L). Dilutions of a variety of human serum samples show a parallel relationship with the standard EPO. Clinical validation of the RIA was confirmed by appropriate increases or decreases of EPO levels in various types of anemia and polycythemia. Serum EPO levels were also measured in volunteers participating in an autologous blood donation study. The RIA proved to be quite sensitive, detecting small increases even after a single unit phlebotomy. This RIA of human EPO meets all the requirements of a routine clinical assay in terms of specificity and clinical sensitivity and can be easily conducted in routine clinical laboratories.

Erythropoietin↗