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Biomedical subjects

M T Parviainen

Publications and source records attributed to M T Parviainen.

33 records · Page 2Linked to original sources
PubMed1988

Alkaline phosphatase isoenzymes in serum determined by high-performance anion-exchange liquid chromatography with detection by enzyme reaction.

This rapid, reproducible method for separating and determining individual alkaline phosphatase (EC 3.1.3.1) isoenzymes in serum is based on high-performance liquid chromatography with a weak anion-exchange column (SynChropak AX 300). The isoenzymes so resolved are detected by using an on-line enzyme reaction followed by spectrophotometric monitoring at 405 nm of the 4-nitrophenol formed. Complete diagnostic profiles of the various isoenzymes present in normal and pathological sera are obtained within 20 min. The mean (and SD) normal concentrations of the bone B1 and intestinal isoenzymes in serum of adults were 3.7 (4.3) and 4.5 (3.9) U/L, respectively (n = 14), and of the bone isoenzyme B2 and liver isoenzymes L1 and L2, 5.8 (8.6), 33.0 (10.6), and 12.0 (4.8) U/L, respectively (n = 17). Concentrations of the B2 and L1 isoenzymes in adults over age 40 years differed significantly from those in adults younger than 40 years, that of bone isoenzyme being lower (P less than 0.05) and that of the liver isoenzyme being higher (P less than 0.001) in the younger adults.

Adult↗
PubMed1986

Vitamin D status of children and adolescents in Finland.

3-,9- and 15-year-old children were studied in autumn in order to evaluate their serum 25-hydroxy-vitamin D (25-OH-D) concentration and their vitamin D intake. The 25-OH-D was significantly lower in the 15-year-old than in the other children, but it was satisfactory in all groups as compared to the 25-OH-D of healthy, young adults. The mean dietary vitamin D intake as well as the mean total vitamin D intake including supplements was low in all groups of children. With a vitamin D intake as low as in this study, every house-bound child would be at risk of vitamin D deficiency.

Adolescent↗
PubMed1985

Serum albumin assay with bromcresol purple dye.

Serum albumin was assayed with bromcresol purple using routine clinical chemical photometric analysers. Bromcresol purple and bromcresol green dyes were compared, and albumin assays using these dyes were compared to those made by radial immunodiffusion and rocket immunoelectrophoresis. Bromcresol purple seems to be insensitive to all serum proteins except albumin, and this dye is correlated linearly with radial immunodiffusion and with rocket electrophoresis.

Bromcresol Green↗
PubMed1985

Peroral xylitol increases intestinal calcium absorption in the rat independently of vitamin D action.

The absorption of 45Ca from the diet in the presence of xylitol was investigated with 28 adult male rats. The supplementation of the diet with 10% xylitol for 3 weeks augmented the urinary excretion of 45Ca 2.5-fold p less than 0.001), but did not affect the urinary excretion of sodium. The concentration of calcium in the serum remained unchanged. The serum levels of vitamin D metabolites [1,25-(OH)2D; 24,25-(OH)2D, and 25-(OH)D] did not correlate with the augmentation of Ca absorption. The diuretic effect of xylitol and the complex formation between polyols and calcium in rat intestine were considered responsible for the changes in calcium metabolism.

Animals↗
PubMed1984

Serum 25-hydroxyvitamin D levels in Finnish children aged 2 to 17 years.

Serum levels of 25-hydroxyvitamin D (25-OHD) in summer and winter were studied in 564 children aged 2-17 years living in the northern, central or southern parts of Finland. The mean levels of 25-OHD were significantly lower in winter (13.3 +/- 10.8 ng/ml) than in summer (27.2 +/- 10.3 ng/ml) in all age groups (p less than 0.001). The mean 25-OHD levels in the northern part of the country did not differ significantly from the others. In both seasons the levels of 25-OHD were lower in the 11-17 year age group than in younger children. In that age group 22.4% of the children had serum levels of 25-OHD below 5 ng/ml (the limit of risk for rickets), compared to 16.8% of children 6-10 years old and 7.5% of children 2-5 years old, but none of the children showed any laboratory evidence of rickets.

Adolescent↗
PubMed1984

Serum amylase and isoamylase assay on the Hitachi 705 automatic clinical chemical analyzer.

The automated continuous alpha-amylase assay using p-nitrophenyl-alpha-D-maltoheptaoside (Boehringer Mannheim) as substrate on the Hitachi 705 clinical chemical analyzer, was compared with the Phadebas Kinetic Amylase Assay (Pharmacia Diagnostics) on the Hitachi 705. The two methods showed good correlation. The precision varied from 1.0 to 2.5% (CV) within-day and from 1.1 to 5.6% (CV) day-to-day. The substrate, p-nitrophenyl-alpha-D-maltoheptaoside, was also applied to an automated isoamylase assay. The amylase inhibitor from wheat was used to determine the ratio of pancreatic and salivary amylase activities of serum. About 80% of salivary type amylase was inhibited up to an activity level of 1000 U/l, while inhibition of pancreatic type amylase activity was only 10-15%. Ratios of pancreatic to salivary amylase from 0.1 to 10 can be evaluated in serum with wheat inhibitor. The precision of the isoamylase determination by the Boehringer amylase method was acceptable.

Amylases↗
PubMed1984

A method for routine estimation of vitamin D activity in human and bovine milk.

To estimate the antirachitic activity of human and bovine milk, we developed a modern biochemical method for determining vitamin D metabolites in milk. Vitamin D metabolites were assayed from milk whey and from whole milk. Milk whey yielded poor recovery of both endogenous and added vitamin D, suggesting a marked loss of vitamin D activity to milk fat during homogenization and separation of the milk whey. A method for assaying the vitamin D metabolites in whole milk involves 1) lipid extraction, 2) cold methanol and ether precipitation, 3) alkaline backwash to reduce the amount of interfering lipids, 4) an efficient reverse-phase preparative purification, 5) an additional silica purification for vitamin D, 6) an analytical high-performance liquid chromatography, and 7) separate sensitized protein-binding assays for vitamin D and 25-hydroxyvitamin D. The method for whole milk resulted in good recovery of added vitamin D, and levels of assayed metabolites and their calculated antirachitic activity agreed well with earlier reports, that is, about 10-50 IU of vitamin D activity per liter.

Animals↗
PubMed1983

Determination of protein content in aqueous humour by high-performance gel filtration chromatography.

High-performance liquid chromatography (HPLC) was used to study the protein content of aqueous humour in 17 cataract patients. High-performance gel filtration chromatograms (HPGFC) of the aqueous humour showed 7-12 peaks with low concentrations (mean 0.085 micrograms/microliter) of high molecular weight proteins (peak 1, MW 250 000 or more) and low levels (0.01 micrograms/microliter or less) of IgA (peak 2) and of IgG (peak 3). The fourth peak (MW about 65 000) containing albumin and obviously also trasferrin was the major peak (mean 0.596 micrograms/microliter) at HPGFC of a normal aqueous humour. Lysozyme (peak 6, MW 35 000) occurred in small amounts in the aqueous humour (mean 0.064 micrograms/microliter). The last 6 peaks matched for peptides and amino acids (MW 10 000 or less). It is concluded that HPLC may be a useful preparative method in characterization, separation, and partial purification of immunoglobulins, immune complexes, and other proteins of aqueous humour.

Aged↗
PubMed1983

Immunonephelometric determination of retinol-binding protein in serum and urine.

An immunonephelometric method developed for measurement of retinol-binding protein (RBP) in serum and urine can detect it in concentrations of about 30 micrograms/L, which is in the lower limit of its normal concentration in urine (range 0-0.56 mg/L; mean +/- SD 0.19 +/- 0.15; n = 44). Urinary RBP was increased (range 0.93-29.5 mg/L) in all of 25 urine specimens from 13 subjects being treated with aminoglycoside (tobramycin). Urinary excretion of RBP was correlated (r = 0.83) with the excretion of beta 2-microglobulin. The within-assay and day-to-day precision (CV) was determined over the detection range of 0.03-8 mg/L. Within these limits the corresponding CVs varied from 4 to 27% and from 8 to 30%, respectively. The method had fairly good precision within the optimal measuring range of approximately 0.4 to 4.5 mg/L for both urine and 20-fold diluted serum samples. For various RBP concentrations our analytical recovery was 89-114% of added RBP. Results by this method correlated well (r = 0.96, n = 24) with those by a radial immunodiffusion method.

Immunodiffusion↗
PubMed1983

Vitamin A, D and E status in a Finnish population--a multivitamin study.

The serum concentrations of the three fat-soluble vitamins A, D and E, and the serum transport proteins for the first of these, were measured during the winter and summer in a healthy adult Finnish population. No statistically significant differences were found in the levels of vitamins A and E between the seasons. However, a marked seasonal variation was found in the levels of vitamin D metabolites, the serum concentrations of 25-hydroxyvitamin D and 24,25-dihydroxyvitamin D being higher in summer, and that of 1,25-dihydroxyvitamin D somewhat higher in winter, whereas the concentration of vitamin D-binding globulin remained constant throughout. The serum concentrations of vitamins A and E showed a marked interrelationship with a significant correlation (r = 0.512, P less than 0.001, n = 80). No outright deficiencies of the vitamins were found in this study, but the serum concentrations of 25-hydroxyvitamin D were rather low in winter. Supplementation with a moderate dose of vitamins A and E over a 2-month winter period did not affect the serum concentrations of these vitamins, whereas 250-500 i.u. of vitamin D daily markedly elevated the low 25-hydroxyvitamin D concentrations.

Adult↗
PubMed1982

Immunonephelometric quantification of serum vitamin D-binding globulin.

Rapid quantification of serum vitamin D-binding globulin (VDBG) is described. An immunonephelometric method was developed and compared with the conventional immunodiffusion method for VDBG. A correlation coefficient of 0.896 (P less than 0.001) was found with a regression line y = 0.965x + 0.011 (n = 23). The within-assay and day-to-day coefficient of variation of the immunonephelometric method was 6 and 11% at 0.150 g/l (low VDBG concentration), 5 and 7% at 0.230 g/l (normal), and 4 and 8% at 0.570 g/l (high). Levels of VDBG and total 25-hydroxyvitamin D (25(OH)D, 25(OH)D2 + 25(OH)D3) were analysed from 33 serum samples obtained in April-May 1980 from 14-month-old children undergoing vitamin D substitution. 25(OH)D was extracted from 0.1-0.5 ml serum followed by semipreparative silica column chromatography and final quantification by a competitive protein-binding method. The VDBG mean value was 0.308 +/- 0.068 g/l (SD) and 25(OH)D had a mean value of 121 +/- 70 nmol/l (SD). There was no significant correlation between the levels of VDBG and 25(OH)D. The results of this study in general agreed well with other findings.

25-Hydroxyvitamin D 2↗
PubMed1981

An improved method for routine determination of vitamin D and its hydroxylated metabolites in serum from children and adults.

A method for routine determination of vitamin D and its major metabolites 25-hydroxyvitamin D (25(OH)D), 24,25-dihydroxyvitamin D (24,25(OH)2D) and 1,25-dihydroxy-vitamin D (1,25(OH)2D) in serum samples from normal children and adults has been developed. Methodological improvements enable a rapid and accurate analysis of 25(OH)D and also the microscale screening of other metabolites present in large concentrations in serum. Vitamin D and its metabolites are extracted from serum samples using hexane/propan-2-ol, which allows a convenient separation of the water soluble and lipid soluble fractions from each other and also from proteins. Preparative silicic acid chromatography was used to separate vitamin D from its metabolites and also from the major portion of co-eluting lipid contaminants. An automated LC solvent delivery and sample introduction system was used to achieve the rapid separation of metabolites. Vitamin D was further purified using adsorption high-performance liquid chromatography and assayed using reverse phase high-performance liquid chromatography connected with UV detection. The 25(OH)D fraction from the preparative chromatography was measured by a competitive protein-binding assay along with 24,25(OH)2D, which was purified by reverse phase high-performance liquid chromatography along with 1,25(OH)2D. A diluted human serum from a pregnant woman (3rd trimester of pregnancy) was used as source of the binding protein for 25(OH)D and 24,25(OH)2D. 1,25(OH)2D was determined by a competitive protein-binding assay using a diluted cytoplasmic 1,25(OH)2D receptor protein isolated from the intestinal mucosa of rachitic chicks. Vitamin D and its metabolite levels were assayed in serum samples from normal children and adults.

24,25-Dihydroxyvitamin D 3↗
PubMed1981

25-hydroxyvitamin D2, 25-hydroxyvitamin D3 and total 24,25-dihydroxyvitamin D in human serum.

An assay procedure capable of determining 25(OH)D2 (25-hydroxyvitamin D2), 25(OH)D3 (25-hydroxyvitamin D3) and total 24,25(OH)2D (24,25-dihydroxyvitamin D) in a single 2-5 ml sample of human serum is described. The assay involves methanol/chloroform extraction of serum lipids followed by separation of the mono- and dihydroxyvitamin D metabolites and purification from interfering contaminants by chromatography on Sephadex LH-20 and by high-performance liquid chromatography (HPLC). 25(OH)D2 and 25(OH)D3 are quantified by HPLC using UV detection. Total 24,25(OH)2D is routinely measured by a competitive protein-binding (CPB) assay with human serum as a source of the binding protein. Mean values (+/- SD) in 16 normal human serum samples taken in October-November were: 25(OH)D2 5.1 +/- 2.2 ng/ml (12.8 +/- 5.5 nmol/l); 25(OH)D3 16.6 +/- 4.4 ng/ml (41.5 +/- 11.0 nmol/l); total 25(OH)D 21.7 +/- 4.9 ng/ml (54.3 +/- 12.3 nmol/l); total 24,25(OH)2D 1.6 +/- 0.6 ng/ml (3.8 +/- 1.4 nmol/l) and the ratio 24,25(OH)2D/25(OH)D 0.066 +/- 0.024. The ratio was 0.048 +/- 0.009 in women and 0.081 +/- 0.022 in men (p less than 0.002). Values in three serum samples taken from patients receiving vitamin D3 therapy were: 25(OH)D2 4.1 +/- 2.7 ng/ml (10.3 +/- 6.8 nmol/l); 25(OH)D3 46.6 +/- 20.9 ng/ml (116.5 +/- 52.3 nmol/l); total 24,25(OH)2D 3.4 +/- 1.9 ng/ml (8.2 +/- 4.6 nmol/l); 24,25(OH)2D/25(OH)D 0.075 +/- 0.022.

24,25-Dihydroxyvitamin D 3↗