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Biomedical subjects

P Vainio

Publications and source records attributed to P Vainio.

At least 55 records · Page 3Linked to original sources
PubMed1995

Ultrasound attenuation of the calcaneus in normal subjects and in patients with wrist fracture.

We determined broadband ultrasound attenuation (BUA) of the calcaneus, and bone mineral density (BMD) of the spine, proximal femur and radius in 137 healthy subjects (79 women and 58 men) and in 56 women with Colles' fracture. The repeated measurements on 9 healthy subjects indicated a short-term reproducibility (coefficient of variation) of 4 percent for BUA. There was a small (7 percent) but significant difference in BUA between normal men and women. The age-dependence in normal subjects was weak. When all the study subjects were pooled, modest correlations between BUA of the calcaneus and BMD at all measured skeletal sites were found (rs values 0.3-0.4). However, it was not possible to make an accurate prediction of the axial BMD, using BUA. BUA values were 13 percent lower in the wrist fracture patients than in the age-matched normals. In general, BUA could discriminate the fracture patients from normals as effectively as BMD. As suggested by the physical theory of ultrasound attenuation, our results support the idea that BUA reflects not only the bone density but also other factors related to the structural properties of bone.

Absorptiometry, Photon↗
PubMed1995

Estimation of spinal bone density using conventional MRI. Comparison between MRI and DXA in 32 subjects.

We evaluated the usefulness of MRI T1 and T2 relaxation times in assessing bone mineral status. T1 and T2 relaxation times of L3 were measured in 16 pairs of identical twins (24 men, 8 women), aged 25-69 years. Bone mineral density (BMD), bone mineral content (BMC) and apparent volumetric bone mineral density (BMDvol) of L3 were measured from the same subjects using dual x-ray absorptiometry (DXA). T2 relaxation time correlated inversely with BMD and BMC (r -0.40 and r -0.47, respectively), whereas a significant positive correlation between T1 relaxation time and BMDvol was found (r 0.36). The measurement of T1 may give some information on bone mineral status in clinical MRI measurements when DXA is not available. It is possible that T1 and T2 reflect not only bone density, but also other factors related to bone structure.

Absorptiometry, Photon↗
PubMed1995

The interuncal distance in Alzheimer disease and age-associated memory impairment.

PURPOSE: To examine the value of measurement of the interuncal distance in the diagnosis of mild to moderate Alzheimer disease. METHODS: We measured interuncal distance from coronal MR scans acquired on a 1.5-T imager. We estimated interuncal distance from a total of 141 subjects: 54 patients diagnosed according to the National Institute of Neurological and Communicative Disorders and the Alzheimer's Disease and Related Disorders Association criteria of probable Alzheimer disease, 40 subjects fulfilling the National Institute of Mental Health criteria of age-associated memory impairment, 27 healthy cognitively normal older control subjects, and 20 control subjects younger than 50 years of age. For comparison we normalized interuncal distance for a horizontal line drawn through the inner cranium at the level of the uncus (interuncal distance/intracranial width ratio), for the brain area (interuncal distance/brain area) and for the intracranial area (interuncal distance/intracranial area). RESULTS: The standard interuncal distance and the interuncal distance/intracranial width differed between the young control subjects and the other groups, but did not differ among the control, age-associated memory impairment, and Alzheimer disease groups. The Alzheimer disease group had significantly greater interuncal distance/intracranial area and interuncal distance/brain area compared with age-matched controls. A considerable overlap was found, however, in the values of patients with Alzheimer disease and control subjects. The cutoff point of 30 mm for interuncal distance yielded 37% sensitivity and 72% specificity to distinguish patients with Alzheimer disease from nondemented elderly subjects. Interuncal distance was not significantly related to the clinical severity of Alzheimer disease as assessed by Clinical Dementia Rating Scale and Mini-Mental Status Examination. Instead, there was a strong correlation between standard and normalized interuncal distance and age in the whole study population and in nondemented subjects. CONCLUSIONS: Our results showed that in a series of 54 patients with mild to moderate Alzheimer disease, interuncal distance was not a reliable diagnostic tool. The study also confirmed the strong age dependence for interuncal distance.

Adult↗
PubMed1995

150 mg fluconazole does not substantially increase the effects of 10 mg midazolam or the plasma midazolam concentrations in healthy subjects.

Fluconazole, an azole antifungal agent, moderately inhibits the CYP3A-mediated metabolism of midazolam in vitro. We therefore studied whether such an interaction takes place in vivo following oral administration of these drugs, given as relevant double blinded doses in capsule form. In study I parallel groups of healthy subjects received oral midazolam 10 mg (MID 10) or 15 mg (MID 15), placebo, or MID 10 mg + 150 mg fluconazole (FLU) given 2 h earlier. Objective and subjective performance tests were made before, and 30 and 90 min after the intake of midazolam. MID 10 and MID 15 moderately impaired performance on digit symbol substitution, letter cancellation and flicker fusion tests, and visual analogue scales revealed mild sedation. FLU + MID 10 had similar or slightly stronger effects than MID 10; it differed from MID 10 in that it lowered the flicker fusion threshold and produced subjective slowness and overall impairment. In study II 5 subjects received MID 10 after placebo, after FLU, and after 750 mg erythromycin (ERY) at 1-week intervals, following a crossover and double-blinded study design. Blood was sampled before MID intake and 30, 60 and 90 min after it, and performance was measured. FLU and ERY increased the effect of MID on flicker fusion and letter cancellation performances, and increased the HPLC-assayed plasma midazolam (ERY + 100%, FLU + 50%) in comparison to that measured after MID ingested alone. When the concentrations of midazolam together with its active metabolite alpha-OH-midazolam were assayed by radioreceptor technique the increases caused by ERY and FLU were less and compatible with the pharmacodynamic data.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Clodronate increases bone mineral density in young growing oophorectomized beagles.

Nineteen beagles (8.8 +/- 0.1 months, 8.5 +/- 0.2 kg, mean +/- SEM) were oophorectomized (OX) at the beginning of the study. The dogs were randomly allocated into three groups: control group (OX, n = 5), OX+clodronate 20 mg/kg orally group (OX + 20, n = 7) and OX+clodronate 40 mg/kg orally group (OX + 40, n = 7). Clodronate administration began the day following oophorectomy and was continued for eight months. Bone mineral density (BMD) was evaluated by dual energy X-ray absorptiometry (DEXA) at baseline and at four and eight months and by quantitative computed tomography (QCT) at baseline and at eight months. Bone biopsies were taken at the beginning and at the end of the study. The change in BMD (g/cm2) during eight months was +2.0% (NS) in OX, +2.3% (NS) in OX + 20 and +10.0% (P < 0.01) in OX + 40 group when measured by DEXA, QCT revealed the same results but in a lesser extent. There were no differences in static and dynamic histomorphometric parameters between the groups at the end of the study. In conclusion, clodronate at a dose 40 mg/kg/day orally increases BMD in young oophorectomized dogs.

Absorptiometry, Photon↗
PubMed1994

Do seizures cause neuronal damage? A MRI study in newly diagnosed and chronic epilepsy.

It is a matter of dispute whether or not recurrent epileptic seizures cause neuronal damage in the human brain. We approached this question by measuring the volumes of the amygdala, hippocampus and parahippocampal gyrus with magnetic resonance imaging in 15 controls, 13 unmedicated patients with newly diagnosed epilepsy and 16 patients with chronic drug-refractory epilepsy. In all patients, the seizure origin was in the temporal lobe region and the seizure aetiology was unknown. Newly diagnosed epilepsy patients with seizure lateralization on the left had increased hippocampal right-left difference (p < 0.01) and right/left ratio (p < 0.05) compared with controls. Patients with chronic epilepsy and lateralization on the left had increased hippocampal right-left difference (p < 0.05) and right/left ratio (p < 0.05) compared with controls. In this patient group, the volume of the left hippocampus was 16% smaller than in controls (p < 0.01). The rostral portion of the parahippocampal gyrus was 12% smaller than in controls (p < 0.01). In chronic epilepsy patients with lateralization on the right, we found a statistically non-significant decrease (13%) in the right hippocampal volume compared with controls. In this patient group, the amygdaloid right-left difference (p < 0.05) and right/left ratio (p < 0.05) were decreased compared with controls. The present cross-sectional study provides evidence that mild hippocampal damage is already present in the early stages of epilepsy. Hippocampal damage is more severe in patients with a long history of recurrent generalized seizures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Reduced N-acetylaspartate concentration in temporal lobe epilepsy by quantitative 1H MRS in vivo.

We used proton magnetic resonance spectroscopy (1H MRS) to determine concentrations of N-acetylaspartate (NAA), creatine and choline in vivo (63 MHz) and in vitro (400 MHz) in seven patients undergoing surgical treatment of intractable temporal lobe epilepsy (TLE). Nine healthy volunteers were used as controls for in vivo MRS. NAA concentrations in vivo on the ipsilateral and contralateral sides were 6.5 +/- 1.3 (s.d.) and 7.9 (+/- 2.1) mmol l-1, respectively and 8.6 (+/- 0.8) mmol l-1 in the volunteers. NAA concentration in vitro was 3.2 (+/- 0.9) mumol g-1 wet weight (ww) and the corresponding concentration from the macroscopically intact brain tissue was 4.7 (+/- 1.0) mumol g-1 ww. Thus, in vivo quantitative 1H MRS identified the size of seizure focus in patients with temporal lobe epilepsy.

Adolescent↗
PubMed1994

Increase in cerebral blood flow of right prefrontal cortex in man during orgasm.

The functional anatomy of human emotional responses has remained poorly understood, mainly because invasive experiments in humans are unacceptable due to ethical reasons. The new functional imaging techniques such as positron emission tomography and single photon emission computed tomography have made it possible to study the neurophysiology of living humans noninvasively. We studied the regional cerebral blood flow with semi-quantitative 99mTc-HMPAO single photon emission computed tomography in eight healthy right-handed heterosexual males during organism. The results showed decrease of cerebral blood flow during orgasm in all other cortical areas except in right prefrontal cortex, where the cerebral blood flow increased significantly (P < 0.005).

Adult↗
PubMed1994

Pulmonary deposition and clinical response of 99mTc-labelled salbutamol delivered from a novel multiple dose powder inhaler.

Pulmonary deposition of 99mTc-labelled sulbutamol was determined after delivery from a novel multiple dose powder inhaler (Easyhaler). The clinical efficacy of the inhalation powder, evaluated simultaneously with gamma camera detection, was compared with that obtained after drug delivery from a metered dose inhaler-spacer combination. The study was performed as an open, non-randomized cross-over trial. A single dose of radiolabelled inhalation powder was inhaled on the first and the inhalation aerosol, as control, on the second study day. Sulbutamol sulphate was labelled with 99mtechnetium, and the inhalation powder was formulated by mixing radioactive drug particles with carrier material. Aerodynamic properties of the radiolabelled inhalation powder were similar to those of the unlabelled salbutamol powder. Delivered dose from the breath-actuated powder inhaler was adjusted to be equal to two puffs from a conventional aerosol actuator with a short plastic mouthpiece. Twelve non-smoking asthmatic patients participated in the trial. The mean pulmonary deposition of 24% was obtained after drug delivery from Easyhaler powder inhaler. Clinical efficacy of the medications was similar in terms of area under the FEV1 curve, maximum FEV1 and the improvement ratio. Thus it can be suggested that powder delivery from Easyhaler powder inhaler and the aerosol delivery through the spacer are equally effective.

Adult↗
PubMed1994

Choline-containing compounds in human astrocytomas studied by 1H NMR spectroscopy in vivo and in vitro.

We have studied 14 patients with different grades of astrocytomas using 1H NMR spectroscopy in vivo. Typically, astrocytomas exhibited a low N-acetylaspartate peak, a prominent signal from choline group-containing compounds, and lactate in the 1H NMR spectra in vivo. The uncorrected choline/creatine + phosphocreatine peak area ratios were higher in tumors than in normal brain tissue. Absolute concentration of choline-containing compounds (1.74 +/- 0.09 mmol/L) in the normal brain tissue was not different in any grade of astrocytoma, but total creatine concentration in healthy brain (7.49 +/- 0.30 mmol/L) was higher than that in grade IV astrocytomas (4.84 +/- 0.89 mmol/L). Relaxation constants of choline-containing compounds did not differ in tumors from those determined in normal brain. Perchloric acid extracts of biopsy samples from 35 astrocytomas and 13 samples of normal temporal white matter were analyzed with 1H NMR. Total concentration of choline-containing compounds did not differ between controls and any grade of astrocytoma when the quantification was done in vitro. It is interesting that phosphorylcholine concentration was about twofold greater in grade IV astrocytomas than in controls or other grades of astrocytomas. We conclude that high phosphorylcholine in grade IV astrocytomas may be an indicator of degree of malignancy. The proportional changes within the group of choline-containing compounds observed in vitro were not reflected in the NMR properties of choline signal in vivo.

Astrocytoma↗
PubMed1994

Mineral density in the mandibles of partially and totally edentate postmenopausal women.

Mineral density of the cortical bone in four regions and the spongiosa distal from the mental foramen of the mandible was determined by quantitative computed tomography (QCT) for 77 postmenopausal, 48-56-yr-old women. Of these women, 42 were totally edentulous and 35 had teeth in region d35-d45. The bone mineral densities of different regions of these two groups were compared. Mineral density of the cortical bone on lingual and buccal sides, distal from the mental foramen, was significantly higher among those who had been edentate 12-23 yr than among dentate subjects. No differences were found between those who had been edentate less than 12 or over 23 yr and the dentate group. This study indicates that muscular activity during different phases of edentulousness regulates the density of bone in regions where muscles are attached.

Alveolar Bone Loss↗
PubMed1994

Effect of maxillary edentulousness on mandibular residual ridges.

Bone mineral density (BMD) was measured in five different regions of the mandible of 77 postmenopausal women. These women were also classified according to the remaining, clinically determined alveolar height in the edentulous distal regions of the mandible. The duration of edentulousness in the maxilla and in the mandible was determined anamnestically. All subjects were edentulous in the maxilla, and 42 were also edentulous in the mandible. The other 35 women had teeth only in region d35-d45. This study shows that after extraction of the last teeth in the mandible, the BMD of the cortical bone is not lowered, but that the BMD of the trabecular portion is lowered more by mechanical stress caused by the remaining natural teeth than by maxillary dentures. This feature becomes apparent when duration of edentulousness in the maxilla is compared with the BMD values of different regions in the mandible.

Alveolar Process↗
PubMed1994

Muscle strength and mineral densities in the mandible.

Bone mineral density (BMD) in the femoral neck and lumbar spine was measured for 355 postmenopausal 48- to 56-year-old women and the BMD in five different regions in the mandible for 77. All 355 women were also classified according to the size of the masseter muscle. Both skeletal measures and the BMD of the buccal cortex distally from the foramen mentale were compared with the size of the masseter muscle. This study indicates that functional stress, caused by the masseter muscle, is involved in maintaining bone mineral density in edentulous regions of the mandible. Those individuals who are physically active or are bruxists may lose less mineral, after extractions of teeth, from those regions of the jaw bones where the muscles are attached.

Absorptiometry, Photon↗
PubMed1994

Volumetric MRI analysis of the amygdala and the hippocampus in subjects with age-associated memory impairment: correlation to visual and verbal memory.

Age-associated memory impairment (AAMI) is a common but disputed entity. It is unclear whether AAMI is a phenomenon of normal aging or an early sign of Alzheimer's disease. The present study aimed to identify possible structural abnormalities in the medial temporal lobe of AAMI subjects. We measured volumes of the hippocampus and amygdala by MRI in 16 AAMI subjects and in 16 age- and sex-matched controls and correlated the volumes with subjects' performance on two visual memory tasks (the Benton and the Heaton visual retention tests) and on a verbal memory task (the Buschke-Fuld Selective Reminding Test). The mean hippocampal and amygdaloid volumes normalized for brain size per se did not differ between the two study groups. In controls, but not in AAMI subjects, the right hippocampus was larger than the left. Accordingly, the volumetric asymmetry between the right and left hippocampi was smaller in AAMI subjects than in controls (Student's t test, p < 0.05). The volume of the right hippocampus (r = 0.37, n = 32, p < 0.05) and the magnitude of the asymmetry between the right and left hippocampi (r = 0.38, n = 32, p < 0.05) correlated with total score on the Benton test. We also found significant correlations between the amygdaloid volumes and the performance on visual memory tests but not with score on the verbal memory test.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Accuracy of digital videodensitometry in quantitating contrast medium concentration.

To evaluate the accuracy of digital videodensitometric technique in directly quantitating concentration of contrast medium, iohexol 300 mg I/ml was injected into a 2-mm-diameter plastic tube, in which clean water was circulated at a 190 ml/min flow, for digital subtraction angiography. Altogether 27 injections were performed with 3, 4 and 5 ml volumes at 3-, 4- and 5-ml/s flows of the contrast medium. A time-density curve was achieved by selecting a "vessel" region of interest (ROI) and a background ROI. Then, a frame corresponding to the maximum opacification of the contrast medium could be calculated. Finally, the average density and the time to peak density of the contrast medium were obtained. The average density was statistically higher (p < 0.01) with 5 ml/s flow than with 4- and 3-ml/s flows. Times to peak density reduced as injection flows or volumes increased. The results support the conclusion that digital videodensitometric technique is an accurate method for quantitation of contrast medium concentration during angiography. The angiographic opacification may be improved by injecting the iodine contrast medium with higher flows or larger volumes.

Absorptiometry, Photon↗
PubMed1993

Effect of bone mineral density in skeleton and mandible on extraction of teeth and clinical alveolar height.

Residual ridge resorption of the maxillae and mandible after tooth extraction adversely affects many edentulous people. The jaws of 355 postmenopausal women were examined clinically, and the number of teeth and the clinical height of alveolar ridges in edentulous jaws were determined. Each subject was asked when the last teeth had been extracted. To study the bone mineral status of each woman, the bone mineral densities of the femoral neck and the lumbar spine were measured by dual-energy x-ray absorptiometry. For 77 edentulous or almost edentulous women, the bone mineral density of the mandibular cortex and the spongiosa were measured by quantitative computed tomography. The results were studied to determine whether the general status of osteoporosis or the local bone mineral densities in the mandible affect the time of extraction of teeth or the remaining height of edentulous alveolar ridges. Neither the time when the teeth were lost nor the number of teeth was dependent on the general bone loss, but in some regions, the clinical height was affected.

Alveolar Process↗
PubMed1993

Panoramic mandibular index and bone mineral densities in postmenopausal women.

The panoramic mandibular index was used in a group of postmenopausal women to determine whether it correlates with bone mineral densities of the femoral neck, lumbar area, and the trabecular and cortical parts of the mandible. The bone mineral density values were measured by dual-energy x-ray absorptiometry of the femoral neck and lumbar area and by quantitative computed tomography of the mandible. Linear correlation of the panoramic mandibular index with all bone mineral density values was weak. However, the low and high index subgroup means were clearly dependent on the bone mineral density variables.

Bone Density↗