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Biomedical subjects

P Vainio

Publications and source records attributed to P Vainio.

At least 73 records · Page 4Linked to original sources
PubMed1993

Abnormalities in left ventricular diastolic function in male patients with rheumatoid arthritis without clinically evident cardiovascular disease.

Epidemiological studies have suggested that patients with rheumatoid arthritis (RA) have increased mortality due to cardiovascular disease. We studied cardiac performance in 12 asymptomatic male patients with RA and 14 control subjects to elucidate early disturbances in cardiac function. In echocardiography, isovolumic relaxation time was longer (64 +/- 6 vs. 49 +/- 3 ms, mean +/- SEM, P = 0.010) and peak filling rate (134 +/- 10 vs. 159 +/- 6 mm s-1, P = 0.015) lower in patients with RA than in control subjects, reflecting an impairment in left ventricular diastolic function. Left ventricular systolic function assessed by radionuclide angiocardiography at rest and during exercise was similar in both groups. There were no differences between the patients with RA and control subjects in the heart rate, systolic blood pressure and oxygen uptake during peak exercise. Left ventricular diastolic function is impaired in spite of normal left ventricular systolic function in patients with RA without clinically evident cardiovascular disease and this may contribute to the excess of cardiovascular mortality in patients with RA.

Adult↗
PubMed1993

Cortical bone mineral density in the mandible and osteoporosis status in postmenopausal women.

Mineral density of the cortical bone of the mandible was determined by single-energy QCT (quantitative computed tomography) for 77 menopausal women. Bone mineral densities (BMD) were measured in the buccal and lingual layers of the cortex, distally from the foramen mentale, on both sides of the mandible. All the women were edentulous in that region, and the alveolar processes were far resorbed. These results were compared with the BMD values of the femoral neck, lumbar spine, and trabecular portion of the mandible between the detected layers of cortex. The BMD of the buccal cortex correlated remarkably well with all values, except those of the trabecular portion. Of the women tested, the correlations were lowest in the least osteoporotic group. The values for the lingual cortex did not correlate with other variables as well as did those for the buccal cortex, but in the most osteoporotic part of the sample the lingual cortex values correlated significantly with the BMD of the trabecular portion. The BMD values for the buccal cortex were significantly higher than those for the lingual cortex.

Absorptiometry, Photon↗
PubMed1993

Trabecular bone mineral density of mandible and alveolar height in postmenopausal women.

Mineral density of the trabecular bone of the mandible was determined by single-energy QCT (quantitative computed tomography) for 74 totally or nearly edentulous menopausal women. These results were compared with the bone mineral densities (BMD) of their lumbar area (L2-L4) and femoral collum, measured by dual-energy x-ray transmission, Lunar DPX. The remaining height of the residual ridge at the symphysis of the mandible was measured on computed tomography (CT) lateral projection view, and an index of the residual ridge status was introduced. To determine whether general osteoporosis status affects the remaining height of the residual ridges, we compared these values with all results for bone mineral density. The BMD of the lumbar area and that of the femoral collum correlated well with each other, but the BMD of the trabecular bone of the mandible did not correlate with either of the other two BMD measurements. Measurements of residual ridge height did not correlate with any BMD values. The effect of possible bone loss earlier in life is no longer apparent in mandibular height or trabecular BMD over 20 yr after tooth extractions.

Absorptiometry, Photon↗
PubMed1992

Left ventricular function and dimensions in newly diagnosed non-insulin-dependent diabetes mellitus.

Left ventricular (LV) function and dimensions were assessed with Doppler and M-mode echocardiography in 26 men and 17 women with newly diagnosed non-insulin-dependent diabetes mellitus, and in 13 healthy control men and 13 women. The diabetic men had lower peak filling rate normalized to mitral stroke volume than the control men (mean +/- standard error of the mean, 4.2 +/- 0.1 vs 4.9 +/- 0.3 stroke volume/s, p less than 0.01). The diabetic women had increased LV mass (102 +/- 12 vs 86 +/- 8 g/m2, p less than 0.01) and decreased fractional shortening (34 +/- 1 vs 38 +/- 1%, p less than 0.05) when compared with control women. At 3 and 15 months, 23 diabetic men and 15 women were reexamined. Concomitantly with decreasing blood glucose levels, fractional shortening improved mainly during the first 3 months and was significantly higher in both diabetic men (36 +/- 2 vs 30 +/- 2%, p less than 0.05) and women (38 +/- 1 vs 34 +/- 1%, p less than 0.05) at 15 months than at baseline. In the diabetic men, peak filling rate increased from 4.3 +/- 0.1 stroke volume/s at baseline to 4.8 +/- 0.2 stroke volume/s at 15 months (p less than 0.05). At 15 months, peak filling rate was correlated (r = 0.61, p less than or equal to 0.001) with autonomic nervous function assessed as heart rate variability during deep breathing test in diabetic men who also showed an inverse correlation between LV hypertrophy and heart rate variability throughout the follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Analysis of left ventricular function from gated first-pass and multiple gated equilibrium acquisitions.

99mTechnetium-sestamibi is a new myocardial perfusion imaging agent that offers significant physical advantages over 201thallium for myocardial perfusion imaging. One of these advantages is that it can be used in the assessment of ventricular function by means of first-pass radionuclide angiography (FPRNA), acquired during the injection of the tracer. In this study we compared gated list mode first-pass acquisition with 99mTc-sestamibi (FP-MIBI) to multiple gated equilibrium radionuclide ventriculography (MUGA) with 99mTc-labelled red blood cells for the determination of global left ventricular ejection fraction (LVEF). The study population consisted of 20 patients (mean age 54 years) who were submitted to stress-rest perfusion imaging. Resting FPRNA was performed using 99mTc-sestamibi and the reference data were acquired within a week with the MUGA technique. A linear correlation between FP LVEF and MUGA LVEF gave an r = 0.974 (p < 0.01). Diastolic and systolic timing and velocity parameters had lower correlations between these two methods. We conclude that global LVEF can be precisely measured with 99mTc-sestamibi when compared to usually employed MUGA technique with 99mTc-labelled red blood cells.

Cardiac Output↗
PubMed1992

Bone densitometry of the spine and femur in children by dual-energy x-ray absorptiometry.

The bone mineral content (BMC) and bone mineral density (BMD) of the lumbar spine (L2-L4) and femoral neck were measured by dual-energy x-ray absorptiometry in 84 healthy Finnish children and adolescents aged 6-19 years. Both BMC (g) and BMD (g/cm2) were closely related to age, height and weight (r values from 0.724 to 0.920). When the BMD values were adjusted for age, height and weight, the mean lumbar BMD was higher in girls than in boys (P = 0.001), whereas in the femoral neck the situation was opposite (P = 0.032). Attempts were also made to normalize the BMD data for the size of bones. When BMD values were corrected for the size of bones, the correlation between age and BMDcorr (g/cm3) at the femoral neck disappeared suggesting that apparent volumetric density (g/cm3) did not change significantly during childhood and adolescence. Statistically higher femoral neck BMD and BMDcorr values were found in the study subjects, who were physically active (P less than 0.005). However, given the influence of nutrition and other environmental factors, one must be careful in interpreting the results concerning the determinants of bone mass.

Absorptiometry, Photon↗
PubMed1992

Comparison of instruments for dual-energy X-ray bone mineral densitometry.

While bone mineral densitometry has become a common laboratory test, it is important to pay attention to the compatibility of the results from different instruments. In this study results from three commercially available bone densitometers are compared using both patient and phantom studies. Overall correlation between instruments was good but there were systematic discrepancies in the results. The three instruments provided bone mineral density (BMD) values that differed by as much as 13.5% due to differences as large as 6% in bone mineral content and as large as 7% in bone area. Thus, the BMD values obtained from different manufacturers' instruments are not directly comparable.

Absorptiometry, Photon↗
PubMed1992

Autonomic nervous function and its relationship to cardiac performance in middle-aged diabetic patients without clinically evident cardiovascular disease.

Autonomic nervous function was evaluated in 36 patients with insulin-dependent diabetes mellitus (IDDM), 39 patients with non-insulin-dependent diabetes mellitus (NIDDM) and 48 control subjects, all without clinically evident cardiovascular disease. Valsalva ratio and heart rate variation during deep breathing were lower in both diabetic groups than in the control group. Autonomic nervous function score (ANFS) was more abnormal in patients with IDDM than in control subjects, but was not significantly increased in patients with NIDDM. There was a negative correlation between ANFS and left ventricular diastolic filling evaluated by echocardiography or peak heart rate during exercise in both diabetic groups. There were no correlations between ANFS and left ventricular systolic function at rest or during exercise in any of the groups. In conclusion, autonomic nervous function was abnormal in middle-aged diabetic patients, and it was associated with impaired left ventricular diastolic filling at rest and decreased heart rate response to exercise, but not with left ventricular systolic function.

Analysis of Variance↗
PubMed1991

Esterase activity of synthetic fragments of human adrenocorticotrophic hormone.

The anterior pituitary hormone adrenocorticotrophin (ACTH) has been extensively studied in terms of structure-function relationships and in vivo and in vitro activities of different synthetic fragments of ACTH have been characterized. Here we describe the ability of synthetic fragments of ACTH to hydrolyze a fluorogenic esterase substrate 4-methylumbelliferyloleate (MUBO). The measured esterase activities (in mumol 4-MU mol-1 s-1) were 79.7 for ACTH1-13, 385.9 for ACTH3-18, 503.0 for ACTH1-19, 1249.9 for ACTH1-24 D-ser3, and 1350 for ACTH1-24. Although the significance of the observed esterase activities in the actual molecular mechanisms of action of ACTH remains to be established it is worth noticing that the esterase activities of the different ACTH fragments closely parallel their reported ability to activate the brain lipase as well as their in vivo ability to induce steroidogenesis in adrenal cortex.

Adrenocorticotropic Hormone↗
PubMed1991

Effect of hemodilution on maximal oxygen consumption, blood lactate response to exercise and cerebral blood flow in subjects with a high-affinity hemoglobin.

10 subjects with Hb Linköping (beta 36 Pro greater than Thr), a high-affinity hemoglobin variant, with a P50 of 2.2 kPa (16.5 mm Hg) were investigated before and 3-4 days after normovolemic hemodilution. Blood hemoglobin concentration decreased from 176 +/- 13 (SD) to 146 +/- 15 g l-1 and the red cell volume from 2.77 +/- 0.83 to 2.23 +/- 0.67 l. Maximal oxygen consumption decreased slightly by 2.7 +/- 3.8 ml min-1 kg-1 and maximal exercise power by 11 +/- 23 W; these changes were, however, not statistically significant. Maximal heart rate was unchanged (-1.1 +/- 6.4 beats min-1) while submaximal heart rate was consistently increased on comparable loads after hemodilution compared to before. The exercise ECG was normal both before and after hemodilution. Capillary lactate levels at exercise were always higher after hemodilution than before. Cerebral blood flow was normal both before and after hemodilution in all subjects but one who had a high flow. The grey matter blood flow increased slightly but significantly by 8.6 +/- 10.3 ml min-1 100 g-1 from before to after hemodilution. The results indicate that subjects with Hb Linköping have only limited benefit from their increased blood hemoglobin concentration.

Adult↗
PubMed1991

Removal of inhaled 99mTc-labelled particles of disodium cromoglycate from the lungs.

Disodium cromoglycate particles were labelled with 99mTc by spray-drying technique. The in vitro dissolution profile as well as the leakage of radioactivity from the drug particles were determined using a through-flow cell method. The radioactive drug particles were mixed with a lactose carrier and inhaled from a dry powder device by five healthy volunteers. The removal of the inhaled drug particles from the lungs was evaluated by a gamma camera. A close relationship between the dissolution of the drug as such and the leakage of radioactivity was noted. Gamma scintigraphy indicated a biphasic exponential removal of radioactivity from the lung region. The slow component with the halftime of about 55 min was mainly due to the dissolution of drug particles in the lungs. The halftime of the fast component describing mucociliary clearance was less than 10 min. This process was the dominating one for the removal of the drug from the lungs. The experiment thus showed that the main fraction of the inhaled dose was deposited in the tracheobronchial region. Accordingly, only a small portion of the dose initially deposited in the lung can be absorbed and induce a therapeutic effect.

Aerosols↗
PubMed1991

Effects of inspirease holding chamber on the deposition of metered dose inhalation aerosols.

A modified cascade impaction method as well as a radiotracer technique has been used to assess the effects of the 700 ml collapsible holding chamber (InspirEase) on the in vitro and in vivo deposition of inhaled metered dose aerosols. The in vitro deposition of beclomethasone dipropionate 250 micrograms/dose aerosol administered either through the conventional aerosol actuator with the short plastic mouthpiece or through the InspirEase-device was evaluated with the modified cascade impactor which method imitated the human respiratory tract. For the in vivo study the disodium cromoglycate particles were labelled with pure gamma-radiator 99mTc using a coprecipitation technique based on spray drying. The deposition of the inhaled disodium cromoglycate particles in the human respiratory tract after administration of the drug doses from the devices tested was determined by means of gamma camera. InspirEase increased both in the in vitro and in vivo tests the fraction of the drug dose deposited into the therapeutically significant regions of the respiratory tract. In addition, the therapeutically insignificant fraction deposited in the upper passages and mouth clearly decreased. Thus using the InspirEase holding chamber not only a better lung penetration of the inhaled drug particles can be achieved but also the local side effects would be decreased.

Administration, Inhalation↗
PubMed1991

Nasal distribution of radioactive drug administered using two dosage forms.

The deposition patterns of 99mtechnetium labelled disodium cromoglycate particles administered either from a metered dose aerosol with a conventional nasal adaptor or from a dry powder nasal inhaler were studied using gamma camera. Disodium cromoglycate particles were firstly labelled with 99mTc using the spray drying technique. Both the metered dose aerosol and the dry powder dosage form were formulated using these radioactive drug particles. Seven healthy volunteers inhaled either three aerosol doses or one dry powder dose unit into one nostril. The drug dose reaching nasal cavity after administration from these two dosage forms was about the same. The deposition patterns as well as the changes in distribution due to the mucociliary transport were monitored by a gamma camera equipped with a low energy all purpose collimator. Initially drug doses deposited in a wider area of the nasal cavity when disodium cromoglycate particles were administered as a dry powder dosage form. In addition, retention index (%) which illustrates the movements of drug particles by mucociliary transport from the initial area of application seemed to be slightly higher for a metered dose aerosol than for a dry powder dosage form. At the end of the 30 minutes measuring period the area of the mucosal layer covered by radioactive drug particles was clearly wider for the dry powder dosage form than for the metered dose aerosol. Thus it is well possible to administer drug particles effectively into the nasal cavity as a dry powder dosage form.

Administration, Inhalation↗
PubMed1991

Deposition and gastrointestinal transit of conventional sucralfate tablets.

Sucralfate was labelled with 99mTc by the stannous reduction method. Tablets were compressed using 1 g of radioactive sucralfate and suitable additives. On the first test day, five fully informed healthy volunteers were given one radioactive tablet of sucralfate each, following 10 h fasting. On the second test day, the sucralfate tablet was given after a standard meal. The gastrointestinal transit of the 99mTc-labelled sucralfate was evaluated using gamma camera technique. The labelling of sucralfate with 99mTc by the stannous reduction method enables the deposition and the transition of sucralfate in the gastrointestinal tract to be monitored. The tablets disintegrated almost immediately after administration and the released sucralfate distributed homogenously over the entire stomach area, in both fasted and fed subjects. Transit from the stomach into the intestine was noted already 10 min after administration in fasted subjects, whereas the gastric emptying of sucralfate was markedly delayed in fed subjects. To achieve a wider and more homogenous distribution in the GI-tract, sucralfate tablets should be taken before eating.

Adult↗
PubMed1990

Effect of the new spacer-device on the deposition of the inhaled metered dose aerosol.

The effect of the new spacer-device on the in vitro and in vivo deposition of inhaled drug particles was studied. The in vitro deposition of beclomethasone dipropionate 250 micrograms/dose aerosol administered either through the conventional aerosol actuator with the short plastic mouthpiece or through the new pear-shaped spacer-device was evaluated with the modified cascade impactor method. For the in vivo study the disodium cromoglycate particles were labelled with a pure gamma-radiator 99mTc using a coprecipitation technique based on spray drying. The deposition of the inhaled disodium cromoglycate particles in the human respiratory tract after administration of the drug doses from the devices tested was determined by means of a gamma camera. The new spacer-device increased both in the in vitro and in vivo tests the fraction of the drug dose deposited into the therapeutically significant regions of the respiratory tract. In addition, the therapeutically insignificant fraction deposited in the upper airways and mouth clearly decreased. Thus using the new spacer-device evaluated in this study the local side effects would be decreased.

Aerosols↗
PubMed1990

In vivo evaluation of the new multiple dose powder inhaler and the Rotahaler using the gamma scintigraphy.

Deposition of 99mTc-labelled particles of disodium cromoglycate in the respiratory tract was evaluated after inhalation from two dry powder inhalers. The inhalers tested were a new multiple dose powder device (Chiesi Farmaceutici) and the Rotahaler powder device (Glaxo). Fractional deposition in the whole lung area, the upper respiratory passages and the stomach, as well as in the inhaler, was measured using a gamma camera. Ten healthy volunteers participated in the inhalation test. The mean, whole lung deposition of the inhaled disodium cromoglycate particles was about 9 per cent of the dose for the both devices. The deposition patterns of the inhaled drug doses in the lung area given by the devices were, however, clearly different. The Chiesi powder inhaler was more efficient in dispersing the drug particles into the therapeutically important alveolar regions of the lungs. The fraction of the dose retained in the inhaler was significantly higher for the Rotahaler than for the Chiesi powder device. On the other hand, the deposition in the upper passages was somewhat larger for the Chiesi device than for the Rotahaler. According to the deposition results of this study, a new multiple dose powder inhaler can be useful in inhalation therapy.

Animals↗