A coherent/Compton scattering method employing an x-ray tube for measurement of trabecular bone mineral content.
Explore the source record for details and available documents.
Bone and Bones↗
Biomedical subjects
H Olkkonen
Publications and source records attributed to H Olkkonen.
Caries reduction in rats through F + Mg supplementation of dietary sucrose with observations on bone mineral density and soft and hard tissue minerals.
Two control diets with different sucrose contents (44% and 22%) were given to weanling rats for 55 d. The test diets were supplemented with an F + Mg combination, 75 parts/10(6) F as NaF + 50 parts/10(6) Mg as MgO and 38 parts/10(6) F + 25 parts/10(6) Mg, respectively, i.e. using the same supplement/sucrose ratio in each test diet. The supplementation in each test diet caused the same percentage fissure caries reduction, but the absolute mean caries scores were higher in the high-sucrose groups than in the respective low-sucrose groups. Enamel solubility was reduced by the supplementation. Despite the high fluoride supplementation, no untoward effects were recorded in growth and in aortic, heart, and renal calcium contents. Bone mineral density was reduced in the low-sucrose controls and slightly reduced in the high-sucrose F + Mg supplemented rats, as compared with the high-sucrose controls.
Animals↗
A 55Fe excited x-ray fluorescence method for the analysis of Ca content in enamel.
A 55Fe excited X-ray fluorescence method has been developed for the quantitative nondestructive analysis of Ca content in surface layers of teeth. To eliminate the effects due to curved enamel surface and the localisation of the tooth a special measuring geometry was constructed. The reproducibility of the method remained under 2%. The effect of acid treatment on the Ca content in enamel was demonstrated.
Acid Etching, Dental↗
Zn and Cu content in human cancellous bone.
Duplicate cancellous bone samples from the iliac crest were obtained from autopsies of 88 persons with a normal mineral status and 50 having osteoporotic change due to chronic immobilizing diseases. The following parameters were determined: the minimal density with gamma-ray attenuation, the compressive strength with a strain transducer, the concentrations of Ca, Mg, Cd, Co, Cu, Mn, Ni, Li, Pb, Sr and Zn with an atomic absorption spectrophotometer and the concentration of F with an ion-selective electrode. The data were analyzed with linear multiple regression analysis. Altogether 34.8 per cent of the Zn concentration was accounted for in all the variables. The selected variables, after the nonsignificant and those with very low explanatory power were removed, explained 38.3 per cent. The two most important variables were the F concentration (16.1 per cent) and Cu concentration (13.7 per cent). The third variable was Mn concentration (8.5 per cent). All variables explained 41.7 per cent of the Cu concentration and five selected variables 40.7 per cent, respectively. The concentration of Zn explained itself as much (20.1 per cent) as four other variables (Ca 7.7 pe cent, Mn 5.9 per cent, Sr 3.9 per cent and Co 3.2 per cent) together. Age and sex did not significantly affect the concentration of Zn and Cu. No remarkable difference was found between the bone samples representing a normal mineral status and osteoporosis.
Adolescent↗
The effect of drinking water fluoridation on the fluoride content, strength and mineral density of human bone.
The effect of drinking water fluoridation on the fluoride content of human bone, on cancellous bone strength and on the mineral density of bone was studied by analysing 158 autopsy samples of the anterior iliac crest from persons from two different areas. In the samples from the town of Kuopio, where drinking water has been fluoridated since 1959, the fluoride concentrations were considerably higher than in samples from the surrounding area where low-fluoride drinking water is used. The fluoride content of bones from Kuopio increased significantly with age, while considerably less change with age was found in samples from outside Kuopio. The highest fluoride content in bone ash was observed in women with severe osteoporosis. Cancellous bone strength measured by a strain transducer was statistically significantly higher in women with chronic immobilizing disease from Kuopio, compared with the corresponding group from outside Kuopio. No statistically significant differences in bone strength were found in men. There were no statistically significant differences in bone mineral density, as measured by gamma ray attenuation, between the samples from the fluoridated and non-fluoridated areas.
Age Factors↗
Maternal circulatory response to a single dose of ritodrine hydrochloride during orthostasis in normal and hypertensive late pregnancy.
Placental blood perfusion, the maternal heart rate, and arterial blood pressure were measured before and after a single intramuscular dose of ritodrine hydrochloride during orthostasis in 11 healthy pregnant women, 10 pre-eclamptic patients, and 11 pregnant patients with essentially hypertension. There was a slight increase in placental blood perfusion in the healthy subjects and a significant rise in the pre-eclamptic patients and the women with essential hypertension. The heart rate increased significantly in all groups. No greater changes in the systolic and diastolic blood pressures were observed. The clinical significant of the results is discussed briefly.
Blood Pressure↗
Gamma variate analysis of pulmonary dilution curves for quantitation of left-to-right cardiac shunts.
Left-to-right shunts were quantified in patients with atrial septal defect using a gamma variate least square fit to radionuclide pulmonary dilution curves. All patients were studied with cardiac catheterization. There was a close correlation between the Fp/Fs ratios obtained by oximetry in cardiac catheterization and by gamma variate analysis. The results suggest that the radionuclide dilution method is sufficiently reliable to be used as a screening tests for the detection and quantitation of left-to-right cardiac shunts.
Adolescent↗
Assessment of fat content of liver by a photon scattering technique.
Explore the source record for details and available documents.
Americium↗
Comparison of 113mIn and 133Xe i.v. injection methods for evaluation of placental blood flow.
Explore the source record for details and available documents.
Female↗
Application of the gamma function for the calculation of effective renal plasma flow by [131I]hippuran clearance.
A simplified technique based on the gamma function was developed to determine the effective renal plasma flow (ERPF) by [131I]hippuran clearance. The method requires only one blood sample in addition to standard renography and the calculations can be performed on a small computer. A close correlation was found between the ERPF values obtained by the application of the gamma function and the values yielded by the conventional bi-exponential approach. The present method is well suited for clinical routine use in connection with standard renography.
Humans↗
A method for the assessment of placental blood perfusion using 99mTc pertechnetate.
A radioisotope method was developed for the measurement of placental blood flow using 99mTc pertechnetate as a tracer and a single detector as a measuring device. The results are given as placental perfusion rate (ml/min/ml) calculated from the tracer-appearance curve. The series consisted of 148 healthy pregnant women between the 28th and 42nd week and fifty pregnancies with a hypertensive disease. In healthy subjects the placental perfusion rate increased by about 32% in the period between 28th and 38th week, but there was a large variation. The perfusion rate showed a tendency to diminish at term. In a group of fifty hypertensive pregnancies a highly significant decrease in the perfusion rate was observed when compared with normal subjects. The conclusion drawn is that this method can be used for the quantitative measurement of placental blood supply.
Adult↗
Zinc content of human cancellous bone.
The zinc content of cancellous bone from the iliac crest was determined by the X-ray fluorescence technique in an autopsy series of 28 women and 66 men. The bone-zinc content was statistically related to age, but there was a large variation. It reached a maximum value in the fifth decade and thereafter decreased with age in both sexes. Men with a chronic disease had a lower zinc content than those who had died suddenly. There was a significant correlation between the zinc content and the bone strength in women (p less than 0.01) and in men (p less than 0.05). Zinc is thought to play a part in osteoporosis.
Adolescent↗
Assessment of cardiac blood pools in radiocardiography by various indicator dilution models.
Heart blood pools were evaluated by different indicator dilution models from single detector 113mIn radiocardiographic measurements on healthy subjects. It appeared that generally accepted mathematical expressions based on the nth moments of the radiocardiographic dilution curve overestimate the heart volumes by 30-40%. The study suggests that the indicator dispersion within the heart chambers is an essential parameter affecting the central circulatory dilution process, which ought to be included in the radiocardiographic models. Dispersion models based on the random walk equation, probability density function and the gamma variate model produced consistent heart volumes. The suitability of the dispersion models for clinical routine use is discussed briefly.
Adolescent↗
Ritodrine hydrochloride induced cardiopulmonary and placental hemodynamic changes in normal and hypertensive late pregnancy.
Cardiopulmonary parameters (minute volume, heart rate, stroke volume, right heart, pulmonary and left heart blood volumes), blood pressure and placental blood flow were evaluated in 20 normal patients, nine patients with preeclamptic disease and 12 with essential hypertension in late pregnancy before and 60 minutes after a single i.m. dose of 10 mg of ritodrine hydrochloride. The drug caused a statistically significant increase in heart rate in all the patient groups, while the systolic and diastolic blood pressures were only slightly affected. Minute volume was unchanged in the group of normal patients, but in both hypertensive groups there was a significant increase. The placental perfusion index was statistically nearly significantly decreased in the group of uncomplicated pregnancies, statistically significantly increased in preeclamptic patients, and not affected in the group with essential hypertension. Ritodrine hydrochloride medication can be expected to have a positive effect on placental blood flow only in preeclamptic disease, and then probably in the milder forms of the disease.
Female↗
Numerical analysis of cardiopulmonary blood volumes in 113In(m) radiocardiography.
A theory of streamline flow of a viscous liquid was applied to the calculation of cardiac and pulmonary parameters (minute volume, stroke volume, right heart, pulmonary and left heart blood volumes) in a radiocardiographic model based on the modified gamma function. The practical feasibility of the formulations was tested using a physical flow model. The cardiopulmonary blood volumes measured from 14 normal subjects were consistent with the results obtained by more complex techniques. The present method is manageable on a small computer and is well suited to clinical routine use in connection with standard single detector 113In(m) radiocardiography.
Adolescent↗
A new photon scattering method for bone mineral density measurements.
A new technique for the determination of bone mineral density, based on the detection of both coherently and Compton scattered photons in a narrow beam geometry, is described. Initial results show that this method delivers an accuracy of less than 2% when varying quantities of materials surround the measuring site.
Bone and Bones↗
Proceedings: Measurement of bone mineral density using coherent and Compton scattering.
Explore the source record for details and available documents.
Female↗
Measurement of cancellous bone strength correlations with mineral density, ageing and disease.
A strain-transducer to measure bone strength is presented. Cancellous bone specimens were taken at autopsy from the iliac crests of 28 women and 66 men. There was a good correlation between bone strength, age and bone mineral density. Females had a lower bone strength than males. The bone strength of patients who died of chronic disease known to cause osteoporosis was lower than that of subjects who suffered sudden death. The equipment is also suitable for in vivo studies of human cancellous bone strength.
Adolescent↗