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Biomedical subjects

J O Lund

Publications and source records attributed to J O Lund.

At least 19 recordsLinked to original sources

[Captopril renography in the diagnosis of renovascular hypertension].

The value of renography before and after angiotensin converting enzyme inhibition with captopril (captopril renography) as a test for renovascular hypertension was studied in fourteen hypertensive patients. The captopril renography was performed with 99mTc-DTPA by means of a gammacamera, allowing determination of single kidney glomerular filtration rate (SKGFR). In all patients determination of renal vein plasma renin concentration and renal angiography were carried out. Eleven patients showed an elevated unilateral renin secretion. All of these had a significant decrease of SKGFR in one or both kidneys after captopril. Three patients without a lateralized renal renin secretion showed no change in SKGFR. In five patients with presumed essential hypertension there was no change in SKGFR during captopril renography. Captopril renography with 99mTc-DTPA gammacamera renography is a promising tool for identification of unilateral increased renin secretion in hypertensive patients suspected of renovascular hypertension.

Adult

Post-exercise platelet activation--aggregation and release in relation to dynamic exercise.

Relatively scarce information is found on the period immediately following physical stress, with special reference to human platelet activity. This, in connection with earlier observations of an increase in platelet release products and hyperaggregability following surgical stress, has initiated the present study. We studied platelet function in eight healthy non-mediated volunteers during and 1 h after cycle exercise of submaximal intensity. ADP-induced platelet aggregability was enhanced in the last minute of exercise followed by a decreased aggregability 1 h after. Adrenaline-induced platelet aggregation showed the same attenuation after exercise but no change during work. The release products beta-thromboglobulin and serotonin in plasma showed significant increases after exercise. This is taken as evidence of an enhanced platelet activity following exercise. A normal stress-response, measured as increase in cyclic AMP in plasma, was observed. In conclusion, platelets are activated following moderate exercise and it seems valid to include the post-exercise period in future studies.

Adenosine Diphosphate

Experience with 7,604 bone scintigraphies at time of operation for breast cancer 1977-1987.

From 1977 to 1987, 7,604 out of a total of 20,483 Danish breast cancer patients had a bone scintigraphy in order to exclude or localise osseous metastases. The scintigrams were performed and interpreted at 14 local hospitals. In 1979, standardised guidelines for interpretation were agreed upon. Until 1983, the scintigrams were described centrally, based on the local reports. From 1979, the frequency of positive bone scintigrams suggesting bone metastases stabilised at about 5% of the patients compared with 12 and 20% in 1977-78. The local take-over of description did not change the frequency. The frequency was also stable from 1979 when evaluated in age groups. With increasing age the frequency of positive scintigrams increased. The frequency of positive scintigrams was significantly lower in patients entering a protocol than in those not entering a protocol. The conclusion is that on a nation-wide basis it is possible to establish a stable, uniform interpretation of bone scintigrams after a two-year introduction period.

Adult

Effects of acute hypoxia and CO2 inhalation on systemic and peripheral oxygen uptake and circulatory responses during moderate exercise.

The effect of acute hypoxia and CO2 inhalation on leg blood flow (LBF), on leg vascular resistance (LVR) and on oxygen supply to and oxygen consumption in the exercising leg was studied in nine healthy male subjects during moderate one-leg exercise. Each subject exercised for 20 min on a cycle ergometer in four different conditions: normoxia, normoxia + 2% CO2, hypoxia corresponding to an altitude of 4000 m above sea level, and hypoxia + 1.2% CO2. Gas exchange, heart rate (HR), arterial blood pressure, and LBF were measured, and arterial and venous blood samples were analysed for PCO2, PO2, oxygen saturation, haematocrit and haemoglobin concentration. Systemic oxygen consumption was 1.83 l.min-1 (1.48-2.59) and was not affected by hypoxia or CO2 inhalation in hypoxia. HR was unaffected by CO2, but increased from 136 beat.min-1 (111-141) in normoxia to 155 (139-169) in hypoxia. LBF was 6.5 l.min-1 (5.4-7.6) in normoxia and increased significantly in hypoxia to 8.4 (5.9-10.1). LVR decreased significantly from 2.23 kPa.l-1.min (1.89-2.99) in normoxia to 1.89 (1.53-2.52) in hypoxia. The increase in LBF from normoxia to hypoxia correlated significantly with the decrease in LVR. When CO2 was added in hypoxia a significant correlation was also found between the decrease in LBF and the increase in LVR. In normoxia, the addition of CO2 caused a significant increase in mean blood pressure. Oxygen consumption in the exercising leg (leg VO2) in normoxia was 0.97 l.min-1 (0.72-1.10), and was unaffected by hypoxia and CO2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Acute unilateral obstruction of ureter. Disparity in divided renal function calculated from 131I-hippuran and 99mTc-DTPA renography.

Fifteen patients with acute unilateral obstruction of ureter and 30 control patients were studied with simultaneous 131I-Hippuran and 99mTc-DTPA gamma camera renography. In severe outflow obstruction the relative function of the obstructed kidney was higher when calculated with Hippuran than with DTPA. No difference was found in the control subjects. This means that the glomerular filtration rate of an obstructed kidney may be relatively more reduced than the renal blood flow. Therefore, measurement of the single kidney fraction of total glomerular filtration rate has to be calculated with a glomerular filtered tracer, e.g., 99mTc-DTPA.

Adult

Long term haemodynamic effects of pinacidil and hydralazine in arterial hypertension.

Eight patients with a diastolic blood pressure greater than or equal to 100mm Hg when treated with a diuretic and a beta-blocker participated in a randomised crossover study comparing the haemodynamic effects of adjunctive therapy with pinacidil or hydralazine. The vasodilator dose was increased until the diastolic blood pressure was less than 90mm Hg or the maximum dosage, hydralazine 100mg twice daily, or pinacidil 50mg twice daily, was reached. Treatment continued for 3 to 6 months and a haemodynamic study was performed. After washout, the patients received the alternative treatment. In the upright position, during supine rest and during isometric as well as dynamic exercise, pinacidil lowered blood pressure more effectively than hydralazine. No differences between the 2 treatments were found in heart rate, stroke index, cardiac index, end systolic wall stress or glomerular filtration rate. Pulmonary mean and wedge pressure were lower during treatment with pinacidil. Forearm blood flow was higher and forearm vascular resistance lower during treatment with pinacidil. Cardiac contractility, judged from the systolic time interval ratio PEP: LVET, was lower during treatment with pinacidil compared with hydralazine. The median daily dose of pinacidil was 50mg and that of hydralazine 200mg. It was also noted that during long term treatment, pinacidil seemed more effective in reducing blood pressure than hydralazine.

Antihypertensive Agents

The value of pre-scheduled bone scintigraphies in breast cancer.

During the first 10 years of Danish Breast Cancer Cooperative Group (DBCG), the subcommittee on bone scintigraphy has focused on the value of bone scintigraphy at the time of operation in all patients and then yearly in those considered to be primarily operable (stage I and II). Out of 1175 patients examined at time of operation, bone metastases could be verified by x-ray or histology in only 16, of whom the majority had bone pain and/or spread to other organs. Similarly, around 2.5% per year for the first 3 postoperative years and about 1% per year during the next 4 postoperative years had bone metastases verified by x-ray or histology within 12 months after the latest scheduled bone scintigraphy. It is concluded that bone scintigraphy is of no value in primarily operable patients with breast cancer, and that the examination should be reserved for patients with symptoms and/or signs of bone metastases and for patients with relapse.

Bone Neoplasms

The incidence rate of phaeochromocytoma and Conn's syndrome in Denmark, 1977-1981.

In the years 1977 to 1981, 47 cases of phaeochromocytoma and 19 cases of aldosterone-producing adrenal adenoma (Conn's syndrome) were diagnosed in Denmark as reported to the National Register of Hospital Patients. This corresponds to an average annual incidence of phaeochromocytoma and Conn's syndrome of 1.9 and 0.8 per million inhabitants, respectively. Treatment results were evaluated from the patient's records and follow-up questionnaires. Of 30 surviving patients operated upon for phaeochromocytoma and followed-up after 18-81 months, 23 were normotensive without treatment and seven were mildly to moderately hypertensive. Of 11 patients operated upon for Conn's syndrome, follow-up data at 1-2 years were obtained in seven, of whom five were normotensive and two hypertensive. Phaeochromocytoma and Conn's syndrome are rare diseases. The results of surgical treatment are often gratifying, but not all patients remain normotensive after surgery, even in the absence of recurrence of endocrine disease.

Adolescent

Bone metastases in primary operable breast cancer. The role of a yearly scintigraphy.

In 231 patients with primary operable breast cancer bone scintigraphies were performed yearly from the second to the 6th year until recurrence irrespective of localization was diagnosed, another cancer was detected, or the patient refused further follow-up or died. During the observation period (from 2 up to 7 years after surgery) 13 patients (5.6%) had bone metastases verified by X-ray or histology within 12 months after the last bone scintigraphy. The scintigraphy was positive in only 7 of these patients. The yearly incidence of bone metastases varied between 0.6 and 2.6%. Due to this low incidence and a low cost/benefit, we conclude that a fixed schedule of repeated scintigraphies in primary operable breast cancer patients otherwise free of apparent disease is not justified.

Bone Neoplasms

Metabolism of exercising skeletal muscle during beta 1-selective adrenoceptor blockade.

Concentrations of glycogen, glucose, glucose-6-phosphate and lactate in the lateral vastus muscle were measured in seven subjects before and after dynamic muscle exercise at a work load of 75% of each subject's maximal working capacity, and with and without intravenous administration of the beta 1-selective beta-adrenoceptor blocking agent, atenolol. Pulmonary oxygen uptake was measured during exercise. Heart rate and arterial blood pressure were measured throughout the study. Arterial concentrations of glucose, lactate and free fatty acids were measured at rest and during exercise. The muscle concentration of glycogen and the extent of glycogen depletion with exercise were not influenced by the beta 1-adrenoceptor blocker. Similarly, there was no change in the muscle concentrations of glucose, glucose-6-phosphate and lactate. Heart rate decreased at rest and during exercise. Arterial blood pressure was not influenced by beta-blockade. Pulmonary oxygen uptake decreased by 6.5%. The exercise induced rise in arterial blood concentration of free fatty acids was abolished by beta 1-selective beta-blockade. It is concluded that the decrease in lactate release from exercising muscles during beta 1-adrenoceptor blockade seen in other studies cannot be explained by an impaired breakdown of muscle glycogen. It may be inferred, however, that a reduced availability of free fatty acids in the exercising muscles during beta 1-selective (and non-selective) beta-blockade may enhance the combustion of pyruvic acid and thereby decrease the production of lactate.

Adult

Reliability of a 99mTc-DTPA gamma camera technique for determination of single kidney glomerular filtration rate. A comparison to plasma clearance of 51Cr-EDTA in one-kidney patients, using the renal clearance of inulin as a reference.

In a recent paper we described a method for calculation of single kidney glomerular filtration rate (SKGFR) from the 99mTc-DTPA renogram obtained by gamma camera. Determination of the injected dose and collection of urine or blood was not needed. In this paper the reliability of the method was compared to other methods for estimation of GFR in 20 unilaterally nephrectomized patients. The renal clearance of inulin served as reference measure of GFR. The values for SKGFR obtained from the renograms and from the estimated endogenous creatinine clearances according to serum creatinine concentration and a nomogram were both accurate. The reliability of the renography method was significantly better judged by less variance in the estimates. SKGFR calculated from the plasma clearance of 51Cr-EDTA overestimated the renal clearance of inulin on an average by 11.3%. No difference was found in the variance of the values obtained from the renograms and from the plasma clearances of 51Cr-EDTA compared to the renal clearance of inulin. Apart from the inaccuracy in the GFR values calculated from the plasma clearance of 51Cr-EDTA, the reliability of these two methods was equal. The day to day variation of SKGFR estimated from the renograms in 24 patients (48 kidneys) with SKGFR values from 5 to 76 ml/min was 8.8%. This equals the day to day variation in the plasma clearance of 51Cr-EDTA.

Aged

Acute hemodynamic effects of pinacidil and hydralazine in essential hypertension.

In a double-blind, randomized, crossover study, the effects of intravenous pinacidil, 0.2 mg/kg, were compared with those of hydralazine, 0.3 mg/kg, before and after beta-adrenoceptor blockade in six subjects with hypertension. Both drugs equally reduced total peripheral resistance by about 40%. Pinacidil reduced mean blood pressure by an average of 30 mm Hg, while the reduction after hydralazine was 10 mm Hg. The difference in antihypertensive effect resulted from greater increases in heart rate, cardiac contractility (systolic time intervals), and cardiac index (thermodilution) after hydralazine. These effects after hydralazine could not be fully abolished by beta-blockade, as could the effects after pinacidil. Pinacidil decreased pulmonary blood pressure, whereas there was a slight rise in pulmonary blood pressure after hydralazine. Forearm blood flow (venous occlusion strain gauge plethysmography) increased equally after both drugs; thus pinacidil decreased forearm vascular resistance more than hydralazine did. Serum concentrations of both drugs were within the therapeutic range and correlated with the fall in mean blood pressure. Five subjects complained of side effects after hydralazine, but none were reported after pinacidil. Hydralazine increased myocardial oxygen consumption (as estimated from the rate-pressure product) by 35%; there was no change after pinacidil. It is suggested that hydralazine has direct cardiostimulatory effects that limit its antihypertensive effectiveness. These effects increase myocardial oxygen consumption and may be responsible for the common and sometimes severe cardiovascular side effects of hydralazine.

Adrenergic beta-Antagonists

A follow-up study of hypertensive patients after operative treatment of unilateral renovascular or renal disease.

A study of 44 hypertensive patients with unilateral renovascular or renal parenchymal disease is presented. All patients underwent corrective surgery. Out of the 44 operated patients, five did not participate in the follow-up examination. The remaining 39 patients constitute the study population. The effects of surgery on the hypertensive state could be evaluated in 35 patients, whereas four died less than two months after the operation. Follow-up studies were carried out at 8-60 months after the operation. The average period of observation was 32 months; 24 patients were observed for more than two years. As a group, the patients had severe hypertension with extensive target organ damage and widespread atherosclerosis. A fairly rigorous selection process was applied, and an unsatisfactory response to medical management was considered a point of major importance. In the majority of cases, renovascular lesions were atherosclerotic, with only two cases of fibromuscular dysplasia. Unilateral nephrectomy was performed in 32 patients, whereas seven underwent reconstructive vascular surgery. Out of 35 patients, 22 (63%) were cured, 8 (23%) improved and 5 (14%) unaltered. A gratifying regression of hypertensive lesions in target organs was observed in patients who were cured or improved by surgery. The frequency and severity of postoperative complications were related to the presence of extrarenal vascular disease.

Adult

Pseudohypoaldosteronism. Clinical, biochemical and morphological studies in a long-term follow-up.

A boy with pseudohypoaldosteronism was followed from birth to the age of 7 years. Failure to thrive, vomiting, dehydration, hyponatraemia and urinary sodium loss were prominent findings. Urinary excretion of corticosteroid metabolites was normal. Before treatment, excessively high plasma renin concentration was found, associated with a marked activation of aldosterone secretion. A renal biopsy showed pronounced hypertrophy of the juxtaglomerular apparatus. Persisting metabolic acidosis and an insufficient urinary acidifying capacity suggested the presence of distal renal tubular acidosis. Treatment with sodium bicarbonate and sodium chloride from 19 to 31 months of age resulted in normal growth and normal physical and mental development. The plasma electrolytes were normalized but a pronounced activation of the renin-aldosterone system persisted after therapy, and on sodium restriction this system responded with a considerable further activation.

Aldosterone

Lung split function test and pneumonectomy. A lower limit for operability.

Regional 133Xe ventilation/perfusion studies were used to predict residual lung function after pulmonary resections. The accuracy of the method was good as checked by postoperative spirometry in 11 patients. In 25 patients with impaired lung function and pulmonary cancer, who were consecutively selected for surgery, the predicted postoperative maximal breathing capacities (MBC) ranged from 17 to 41 l/min-1 m-2. No patients became permanent pulmonary invalids. One patient died from myocardial infarction, 7 had transient pulmonary insufficiency and 17 patients survived operation without complications. Perfusion studies alone proved as reliable as perfusion/ventilation studies.

Aged

Evaluation of fracture healing in man by serial 99mTcSn-pyrophosphate scintimetry.

Serial 99mTc-pyrophosphate (99mTcPP) uptake measurements were performed, during the healing period, in 12 patients with fracture of the distal end of the radius without displacement. A peak value in uptake ratio was seen within 4 weeks in all patients. For clinical reasons the patients were divided into a normal healing and a slow healing group. 99mTcPP uptake at 6 weeks after the fracture was significantly higher in the slow healing group. Quantitation of the healing process in forearm fractures is possible using 99mTcPP and a gamma camera, and concentrating on small selected areas of interest.

Adult