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Biomedical subjects

R Lappalainen

Publications and source records attributed to R Lappalainen.

At least 73 records · Page 4Linked to original sources
PubMed1989

Au, Cu, Sn, Zn and Ag ion release from some Cd-free gold solders.

The aim of this study was to determine the release of Au, Cu, Sn, Zn, and Ag from five commercially available Cd-free gold solders. The electropotential system in modified Fusayma solution was used. The cycle process was repeated between +/- 250 mV for 24 hours. To study the ion release, samples of solution were analysed during the process. Rapid release of Zn from most alloys was found. Cu and Ag ions were also released, but only small amounts of the latter. Au showed very good passivation up to 24 hours. The use of soldered joints should be reduced in order to minimize corrosion.

Copper↗
PubMed1989

Assessment of labial salivary gland changes in patients with rheumatoid arthritis by subjective and quantitative methods.

Biopsy of the minor salivary glands is an accepted method in the diagnosis of Sjögren's syndrome, the most characteristic feature being the prominent inflammatory cell infiltration. However, difficulties exist in the early diagnosis of Sjögren's syndrome. The present study was conducted to analyse by subjective and quantitative methods the morphological changes of the salivary glands in patients with rheumatoid arthritis (RA) frequently complicated by Sjögren's syndrome. The subjects of this study were 71 RA patients (mean age 54 +/- 15 years) and their 45 healthy age-matched controls (mean age 60 +/- 14 years). The histologic parameters evaluated were: inflammatory cell infiltration; acinar atrophy; fibrosis, and fatty infiltration. Statistically significant differences between the RA and the control groups were found in all parameters (p less than 0.001) except the fatty infiltration. This indicates that destruction of the salivary glands including fibrosis and acinar atrophy is associated with RA. Only the fatty infiltration seems to be an age-dependent change. All salivary gland biopsies of the RA patients were photographed and evaluated planimetrically, for the same parameters as in the subjective evaluation. An excellent reproducibility between the two methods was found, thus indicating the applicability of the subjective evaluation in the assessment of early salivary gland changes in RA patients.

Adult↗
PubMed1988

Blood flow, histomorphology and elemental composition of the canine femur after physical training or immobilization.

Effects of long-term physical training (treadmill running 4 km/day for 15 weeks) and immobilization (casting of the limb for 11 weeks) on the blood flow, bone marrow uptake of radio-colloid, histomorphology as well as elemental composition of the proximal canine femur were investigated. In the runners both bone marrow and mean bone perfusions measured with a 133Xe washout method were increased by 53.5% (P less than 0.05) and 54.1% (P less than 0.05), respectively, as compared with the age-matched controls. Bone marrow uptake of [99mTc]tincolloid and volumetric fractions of trabecular bone and bone marrow were not significantly altered after training or immobilization. The amount of zinc measured by atomic absorption spectrophotometry was, however, significantly higher (P less than 0.01) after immobilization as compared with the controls. Consequently, long-term physical training is suggested to stimulate bone metabolism by enhancing its blood perfusion even in the resting state, whereas the increase of zinc content was considered to be linked to the obvious bone resorption caused by immobilization.

Animals↗
PubMed1987

Periodontal conditions with removable complete and partial dentures in the adult population aged 30 years and over.

The periodontal conditions of subjects with different combinations of removable dentures were studied in a representative sample of 8000 subjects, of which 90% were used for the experiment. The number of subjects with removable dentures was 1468. Subjects with removable partial dentures had significantly more pockets and deeper pockets than did those without dentures. The periodontal condition of subjects with a complete denture in the opposite jaw was significantly better than that in other subjects. This was true in both men and women. The results indicated the importance of prophylactic and maintenance care in subjects with removable partial dentures.

Adult↗
PubMed1987

Subjective need of removable denture treatment in Finnish adults.

The aim of this study was to analyse the clinical dental health, use of dental services and socio-economic factors correlating with the subjective need for removable dentures in Finnish adults aged 30 years and older. A total of 2528 persons who had lost one or more natural teeth (wisdom teeth excluded) and who had not been provided with any dentures, were selected for this study. Subjects who had subjective need for prosthetic treatment had statistically significantly fewer teeth and fewer fillings, and more decayed teeth than others. Irregular users of dental services felt the need for a prosthesis more often than did regular users of those services. Irregular brushing of teeth was also associated with a greater need for prosthetic treatment. Men, older individuals and persons with less education and a smaller family income felt the need for prosthetic treatment more often than women, younger individuals and better educated persons. The factors differentiating between the two groups with and without a subjective prosthetic treatment need were analysed by discriminant analysis. The best differentiating factors were frequency of dental visits, caries score, frequency of brushing teeth, family income, number of fillings and sex.

Adult↗
PubMed1987

Release of elements from some gold alloys and amalgams in corrosion.

The release of Au, Ag, Cu and Zn elements from six commercially available gold alloys and three amalgam alloys was studied. The polarizing electropotential system with modified Fusayama solution was used. The cycle process was repeated 500 times between +/- 1000 mV during a period of 5 h 22 min. During the process samples of solution were analyzed in order to follow the release of elements. Results revealed rapid release of Zn from most alloys, release of Ag from most alloys and release of Au from two alloys. Also, rapid release of Cu was found from amalgams but not from gold alloys. Release of Ag from gold alloys showed very good passivation up to 3 h, after which it was released in varying amounts.

Chemical Phenomena↗
PubMed1986

Salivary and serum levels of electrolytes and immunomarkers in edentulous healthy subjects and in those with rheumatoid arthritis.

Chemical analyses of serum and stimulated parotid saliva of 73 edentulous patients with rheumatoid arthritis (RA) and of 36 edentulous healthy controls were performed. The purpose of the present work was to assess the possible correlations between the concentrations of electrolytes and immunomarkers such as lysozyme, IgA, beta 2-microglobulin (beta 2-m) and rheumatoid factor (RF) in serum and saliva. The results of the chemical analyses of the serum showed elevated values for IgA, IgM, lysozyme and beta 2-m. In addition 45 patients were positive for rheumatoid factor. In saliva, the only significant difference between the groups studied was decreased potassium concentration in the RA patients. Nine salivary specimens were RF positive. There was a highly significant correlation between serum beta 2 and salivary IgA, lysozyme, beta 2-m, urea and amylase in the RA patients. In addition, serum lysozyme and RF were related to salivary beta 2-m and urea. However, no such relations could be observed in the controls. These findings indicate that serum immunomarkers have an effect on the salivary constituents in the patients with an altered immunological state. The importance of simultaneous serum analysis is emphasized when salivary levels are to be interpreted.

Adult↗
PubMed1985

Statistical evidence for the relation between citrate and carbonate in human cortical bone.

Bone specimens from the anterior iliac crest were collected post-mortem from 128 subjects whose death had been primarily caused by acute coronary disease or accidents. The cortical bone was separated and used for the following determinations: citrate by an enzymatic method, carbon dioxide by microdiffusion, chloride and phosphorus by spectrophotometry, fluoride by the ion-selective electrode technique, and Ca, Mg, Zn by atomic absorption spectrophotometry. The citrate concentration (+/- SD) was 10.9 +/- 3.1 mg/g (dry weight) and was not age-dependent. A statistically significant negative correlation was obtained between citrate and carbon dioxide, however, which was confirmed by regression analysis. The only statistically significant differences in carbon dioxide and fluoride concentrations between three citrate groups were obtained between the lowest group (3.2-8.7 mg/g) and the highest (13.1-16.8 mg/g). In conclusion an inverse relationship may suggest either an effect of citrate on the binding of carbonate to apatite structures, or that the carbonate concentration is dependent to a slight degree on citrate metabolism.

Adult↗
PubMed1985

Relationships between carbonate, sex and other macroelements in human whole enamel.

Enamel samples were prepared from 40 teeth and CO3, P, F, Ca, Mg and Zn concentrations were determined. The carbonate concentration was higher in women than in men (P = 0.018), otherwise no sex dependence was found. Positive correlations were found between CO3 and Mg (P = 0.001). These relations should be taken into consideration when the solubility of enamel is studied.

Adolescent↗