[A model for standardizing of clinical physiological/nuclear medical results].
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Clinical Laboratory Techniques↗
Biomedical subjects
S L Nielsen
Publications and source records attributed to S L Nielsen.
Evaluation of left-to-right shunts in adults with atrial septal defect using first-pass radionuclide cardiography.
Non-invasive determination of left-to-right shunts at the atrial level was performed by a new procedure using first-pass radionuclide measurement of cardiac output of the right and left ventricle. In 23 patients with coronary artery disease without shunt the mean difference between the cardiac outputs of the right and left ventricle was 0.04 l.min-1, the limits of agreement -0.80 to 0.88 l.min-1 and the 95% confidence interval for the bias -0.14 to 0.22 l.min-1. Right-sided cardiac catheterization was performed to assess the severity of the arterio-venous shunt by oximetry in 18 adult patients with atrial septal defects. The range of pulmonary-to-systemic flow ratios was 1.4 to 5.0 (mean 2.7) by oximetry and 1.3 to 4.4 (mean 2.5) by the radionuclide technique. The mean difference between flow ratios measured by the two methods was 0.25, the limits of agreement, -0.85 to 1.35 and the 95% confidence intervals for the bias -0.02 to 0.52. In two patients the difference in flow ratios was more than 1. In one of these the oximetric value was more than 2, and the radionuclide value less than 2. The limits of agreement between flow ratios determined by repeated measurements were -1.05 to 0.97, and by two independent observers -0.75 to 0.77. The present findings suggest that first-pass radionuclide determination of left-to-right shunts through atrial septal defects is both reproducible and accurate when compared to the oximetric technique.
Aged↗
Effects of alpha-adrenoceptor and of combined sympathetic and parasympathetic blockade on cardiac performance and vascular resistance.
1. Cardiac performance and vascular resistance was studied in seven healthy men by radionuclide cardiography and venous plethysmography before and after alpha-adrenoceptor blockade with phentolamine and after combined alpha-adrenoceptor, beta-adrenoceptor (propranolol) and parasympathetic (atropine) blockade. 2. During alpha-adrenoceptor blockade heart rate and cardiac output increased considerably and left ventricular ejection fraction increased because of increased contractility. Systemic vascular resistance fell both during alpha-adrenoceptor blockade alone and during combined blockade. The increase in calf blood flow was of the same magnitude after combined blockade and after alpha-adrenoceptor blockade alone, and was considerably higher than the fall in systemic vascular resistance. Plasma catecholamine concentrations increased after phentolamine, but the changes were blunted when propranolol and atropine were added. 3. These results indicate that peripheral vasoconstriction especially that exerted by alpha-adrenoceptor nervous tone in skeletal muscle restricts left ventricular emptying of the intact heart. During pharmacologic blockade of the sympathetic and parasympathetic nervous system at rest the chronotropic state is augmented, whereas preload and inotropy are unaffected.
Adrenergic alpha-Antagonists↗
Sham-feeding decreases cardiac output in normal subjects.
The cardiovascular effect of sham-feeding was measured in seven healthy non-obese human subjects by the Fick principle using the carbon dioxide rebreathing method. The subjects were resting in the sitting position and were exposed to the sight and smell but not the taste of a breakfast meal. Cardiac output decreased significantly from a mean value of 4.0 1 min-1 to 3.5 1 min-1 during sham-feeding (Friedman, P = 0.004). The cardiac output returned to basal values in all seven subjects when the sensory stimulus was removed. The decrease in cardiac output was due to a decreased stroke volume, whereas heart rate and blood pressure did not change. The mechanism of the decrease in cardiac output during sham-feeding remains to be established.
Adult↗
Long-term smoking increases transcapillary escape rate of albumin.
Transcapillary escape rate of albumin was measured in 11 young and 10 healthy, elderly male subjects. Approximately half of the subjects were chronic cigarette smokers. Transcapillary escape rate of albumin expressed as percentage of decrease in specific activity of plasma albumin per hour averaged 12.3% in long-term smokers. This value was significantly elevated and twice as high as values measured in young smokers and in young and elderly non-smokers. It is concluded that capillary permeability to albumin is increased in long-term smokers. Further studies are warranted to examine the pathophysiological mechanism and to what extent this abnormality is reversible.
Adult↗
Renal function in patients with untreated acute myocardial infarction.
This study provides data on plasma volume (PV), extracellular volume (ECV) and renal function in 8 untreated patients with acute myocardial infarction (AMI). At day 2 and day 10 after AMI, glomerular filtration rate (GFR), urinary excretion rate of water (Vu), sodium clearance (CNa) and lithium clearance (CLi) were used for assessing reabsorption rates of sodium and water in proximal and distal nephron segments. PV and blood pressure at day 2 were not significantly different from values at day 10. Heart rate (HR), weight and ECV at day 2 were significantly increased when compared with values at day 10 (78 vs. 62 pr. min and 17.0 vs. 16.2 1, respectively). Plasma norepinephrine values were slightly elevated at day 2 and day 10. GFR was initially high and decreased from day 2 to day 10 (118 vs. 104 ml min-1) together with CLi and Ck. However, Vu, CNa and fractional excretion rate of sodium increased markedly from day 2 to day 10. The results suggest that sodium and water retention in the initial phase of AMI without left ventricular failure is due to an increase in tubular reabsorption in distal nephron segments mediated by mechanisms other than the sympathetic nervous system.
Absorption↗
Leucocyte scintigraphy to localize inflammatory activity in ulcerative colitis and Crohn's disease.
The validity of using autologous leucocytes labelled with technetium -99m hexamethyl-propyleneamine-oxine (Tc-HMPAO) for scintigraphy in inflammatory bowel disease was evaluated in 12 patients with clinically active ulcerative colitis (UC) and 10 with Crohn's disease (CD). Colonoscopy and biopsy were used as reference. Scintigrams taken 1 h and 3 h after leucocyte reinjection were evaluated blindly by two independent observer groups. Full agreement was found in 11 of 12 UC patients when compared with colonoscopy but in only 3 of 10 CD patients. Segments with agreement in CD patients often showed neutrophilic granulocyte infiltration at biopsy. The judgements of clinicians and physiologists differed for only 2 of totally 70 UC segments but for 13 of 59 CD segments (kappa, 0.94 and 0.52). It is concluded that Tc-HMPAO scintigraphy might be an alternative to colonoscopy in the control of disease extent in UC. In CD patients the technique might warn about infections complications.
Adult↗
Nosocomial pneumonia in an intensive care unit in a Danish university hospital: incidence, mortality and etiology.
We studied the patients admitted to the ICU at a Danish university hospital during 1 year with respect to nosocomial pneumonia (NP). Among 242 patients, who stayed more than 48 h, 23 (10%) developed NP. Patients with NP had significantly higher mortality (43% vs. 19%, p less than 0.05), longer median stay (276 h vs. 99 h, p less than 0.05) and a longer median intubation period (256 h vs. 74 h, p less than 0.05). In the NP group surgical patients were overrepresented as compared to medical patients (74% vs. 45%, p less than 0.05). Thoracotomy, treatment with H-2 blockers and immunosuppression represented significant risk factors. Considering the etiology, Enterobacteriaceae and Pseudomonas aeruginosa constituted 43% of the cases in strong contrast to the low frequency of these pathogens in community-acquired pneumonia. NP in the ICU patient is a resource consuming disease associated with a high mortality (43%), which is related to the frequent severe underlying diseases of these patients.
Aged↗
The value of exercise tests after acute myocardial infarction.
The aim of the present study was to relate the clinical course in patients after a first acute myocardial infarction with the response to exercise-tests performed one month after discharge. 90 consecutive patients who suffered an acute myocardial infarction for the first time were followed-up after 12 months in general practice. Six patients had died, and nine patients had suffered another MI. 23 patients were being treated for heart failure, 51 for angina pectoris, and 8 for arrhythmias. 14 patients received treatment for both heart failure and angina pectoris. Of the patients at work, 17.6% did not return to work because of the heart disease. 80 patients were in function groups I-II and 10 in function groups III-IV (New York Heart Association's Classification). Occurrence of ST-segment displacements was without prognostic value. Left ventricular function index (dRPP) and working capacity (W) were predictive with respect to mortality, heart failure, and angina pectoris requiring drug treatment. Exercise tests following acute myocardial infarction could not predict the chances of returning to work.
Adult↗
Myocardial perfusion at fatal infarction: location and size of scintigraphic defects.
In a consecutive study of myocardial scintigraphy in acute ischemic syndrome, four patients had 99mTc-hexamibi injected intravenously before they developed fatal cardiogenic shock. Planar scintigraphy was performed after death. Slices of the hearts after autopsy were analyzed for scintigraphic and pathoanatomic abnormalities. Location of perfusion defects in planar views of the heart was in good agreement with the scintigraphied, sliced sections. The extent of infarction judged from inspection and formasan staining was much smaller (7%-40% and 6%-43% of the total slice area) than found at scintigraphy, where 83%-92% of the myocardium showed ischemia as defined by a 99mTc-hexamibi uptake below an arbitrary limit on half maximum uptake. Myocardial hypoperfusion might thus aggravate the functional impairment at myocardial infarction and lead to cardiogenic shock.
Aged↗
[Temperature measurement--where, when and how?].
The mercury thermometer may no longer be sold in Sweden, and is soon to be proscribed in the other Scandinavian countries. How reliable are other thermometers, and should body temperature be measured orally, rectally or in some other way?
Adult↗
[The temperature in medical practice].
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Body Temperature↗
Rate of urinary bladder blood flow evaluated by 133Xe washout and radioactive microspheres in pigs.
Urinary bladder blood flow as measured by the washout of locally injected 133Xe and by the simultaneously performed radioactive microsphere reference-sample method was studied in pigs. The washout curves were analyzed according to the initial slope, the corrected initial slope and the total curve. The corrected-initial-slope flow rates were not statistically significantly different from the microsphere whole-wall flow rates. The variability between the methods shown by the test-retest difference revealed only a minor lack of agreement. The bladder blood flow tended to decrease after the intravesical pressure had been increased to 20 cmH2O, but the difference was not statistically significant. Washout of locally injected 133Xe can be used for the evaluation of urinary bladder blood flow in humans and in longitudinal animal studies. The corrected-initial-slope method is recommended for the analysis of washout curves.
Animals↗
Renal clearance of an ionic high-osmolar and a nonionic low-osmolar contrast medium.
One hundred patients with normal serum creatinine concentration underwent intravenous urography with either an ionic high-osmolar (diatrizoate) or a nonionic low-osmolar (iopamidol) contrast medium after randomization. Before injection of the contrast medium, a blood sample was drawn for determinating serum creatinine concentration, and a urine sample for measurement of urine osmolality. Using x-ray fluorescence, the plasma concentration of iodine (contrast medium) was determined on blood samples drawn approximately 3 and 4 hours after injection of the contrast medium. The glomerular filtration rate was calculated by two different formulas: one requiring only a single sample and one requiring at least two samples (standard). There were poor correlations between the standard contrast medium clearance and the serum creatinine concentration, the estimated creatinine clearance (calculated from a nomogram), as well as the urine osmolality. The 3-hour and the 4-hour single-sample values correlated well with the two-sample values for both contrast media. In patients with normal serum creatinine, the glomerular filtration rate determined by measuring the contrast medium concentration in a single plasma sample obtained at 3 hours, is almost identical to the value determined from two samples. Consequently, two samples are unnecessary.
Adult↗
Effect of insulin-induced hypoglycaemia on absorption of unmodified insulin after subcutaneous or intramuscular injection.
The effect of insulin-induced hypoglycaemia on the absorption of iodine-125 labelled unmodified insulin (10 U) from thigh after subcutaneous or intramuscular injection was studied in eight immobilized, supine, normal subjects. Ultrasonic determination of the subcutaneous thickness was used to accurately localize the site for insulin injection. Insulin absorption was studied twice during hypoglycaemia or normoglycaemia in random order. Insulin absorption was similar after subcutaneous and intramuscular injections (residual activity at 5 h: SC 59.3 +/- 5.0 (+/- SE) %; IM 55.2 +/- 3.7%). Hypoglycaemia did not change the disappearance rate of iodine-125 insulin after either subcutaneous (55.0 +/- 4.4%) or intramuscular injection (52.6 +/- 5.7%), despite a plasma glucose nadir of 1.7 +/- 0.2 mmol I-1. In a controlled study under standardized conditions hypoglycaemia has no effect on insulin absorption rate.(ABSTRACT TRUNCATED AT 250 WORDS)
Absorption↗
Silent ischemia and severity of pain in acute myocardial infarction.
An overall low tendency to complain of pain, due to a low perception of pain, has been suggested in the pathogenesis of silent ischemia, independent of the extent of the diseased coronaries and a history of previous acute myocardial infarction. This hypothesis has been tested indirectly in this retrospective study by comparison of the use of analgesics during admission for a first acute myocardial infarction with the occurrence of silent ischemia at exertion tests four weeks after discharge from hospital. The study did not show a lower use of analgesics in patients with silent ischemia, but this may be due to methodologic problems. Suggestions are given for another study design to overcome these problems.
Analgesics, Opioid↗
Plasma glucagon and glucose recovery after hypoglycemia: the effect of total autonomic blockade.
The role of the autonomic nervous system in the glucagon response to hypoglycemia has not been fully clarified. We have studied the effect of total pharmacological blockade of the autonomic nervous system (concomitant alpha- and beta-adrenergic blockade with simultaneous atropine injection) and of isolated alpha-adrenergic blockade on hormonal responses to hypoglycemia and on blood glucose recovery after hypoglycemia in healthy subjects. Neither of the pharmacological blockades had any significant effects on plasma glucagon responses to hypoglycemia nor had they any effect on the rate of blood glucose recovery after hypoglycemia. We conclude that the autonomic nervous system has no major influence on the glucagon response to hypoglycemia in healthy man. Changes in autonomic nervous activity are not essential for blood glucose recovery after hypoglycemia in healthy man.
Adult↗
Sources of variation in 133Xenon washout after subcutaneous injection on the abdomen.
The washout of 133Xenon injected locally in three subcutaneous regions on three volunteers was in a repeated latin square design analyzed regarding flow values and initial clearance. Blood flow showed no dependence on injected volumes (.02-.5 ml), but there was a significant day-day variation and regional and personal differences in subcutaneous blood flow. The initial fast washout was related to the injected volumes due to trauma and dilution of the tissue. From these results precautions are described to increase the validity of the local 133Xenon washout method for measurement of subcutaneous blood flow. In repeated clinical studies it remains important even on the same individuals to record sources of variation apart from the variable to be investigated.
Abdomen↗