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Biomedical subjects

U Turpeinen

Publications and source records attributed to U Turpeinen.

At least 55 records · Page 3Linked to original sources
PubMed1991

Method dependence of interpretation of immunoassay results.

The interpretation of results obtained by immunoassays is affected by many different factors and especially by assay sensitivity and specificity. The introduction of sandwich-type immunometric assays using highly sensitive non-radioactive labels and monoclonal antibodies has greatly improved sensitivity while reducing assay time and simplifying performance. Thus determination of subnormal levels of several hormones has become possible. This approach has also enabled more exact tuning of specificity but at the same time it has introduced the risk of too high selectivity. Hapten assays have also become simpler to perform, but in this case no substantial improvement in assay sensitivity has been achieved.

Animals↗
PubMed1990

Effect of intracavitary radiotherapy on tumor-associated trypsin inhibitor (TATI) in patients with cervical and endometrial cancer.

Tumor-associated trypsin inhibitor (TATI) is a fairly specific serum marker for mucinous ovarian cancer. Very high levels occur in mucinous ovarian cyst fluid, indicating that the elevated levels of TATI in serum are derived from the tumor. However, elevated levels of TATI may also occur in inflammatory disease and after major surgery, suggesting that TATI may also behave as an acute-phase reactant. To further elucidate these questions we have measured the concentration of TATI in urine before and after intracavitary radiotherapy in 13 patients with cervical cancer and 29 patients with endometrial cancer. In 11 patients the concentrations of serum TATI and C-reactive protein (CRP) were also measured. The treatment caused a moderate but significant elevation in the urinary concentration of TATI but affected the serum levels of TATI and CRP only occasionally. The apparent discrepancy between the changes in serum and urine levels of TATI may be explained by the very short (6 min) half-life of TATI in serum. Our results indicate that the mechanisms causing elevation of TATI in urine and of CRP in serum are different. TATI appears to react more rapidly to radiation-induced tissue destruction, whereas CRP is a much more sensitive indicator of bacterial infections.

Adenocarcinoma↗
PubMed1990

Pharmacokinetics of the antiprogesterone RU 486: no correlation to clinical performance of RU 486.

The pharmacokinetics and metabolism of RU 486 were characterized in 17 women who received a single dose of 600 mg of RU 486 for termination of an early unwanted pregnancy. Based on the clinical outcome and serum chorionic gonadotropin values, the subjects were divided into two groups: those who aborted completely (i.e. responders: N = 13) and those who did not respond to RU 486 treatment (i.e. non-responders: N = 4). The serum levels of RU 486, the monodemethylated, didemethylated and hydroxylated metabolites of RU 486 were measured by HPLC preceded by column chromatography. There were no significant differences in the serum levels of RU 486 or its metabolites between the two groups. The serum concentrations of alpha 1-acid glycoprotein, the binding protein for RU 486, were quantitated by immunoturbidimetry. The alpha 1-acid glycoprotein concentrations were similar in responders and non-responders. The metabolism of RU 486 was also studied by fractionating extracts of serum pools of responders and non-responders on thin-layer chromatography, and subsequent RIA analysis of the eluates of the sliced thin-layer chromatography. Spots with similar distribution and percentages of cross-reactivity were found in both groups on the chromatography; the results were also similar to those from a serum pool to which synthetic RU 486 and its three metabolites had been added. Hence it is concluded that failure to abort in response to RU 486 therapy is not associated with altered pharmacokinetics or metabolism of RU 486.

Abortion, Induced↗
PubMed1990

Immunoturbidimetric determination of pregnancy-specific beta 1-glycoprotein (SP-1).

We describe a simple and rapid immunoturbidimetric end-point assay for measuring pregnancy-specific beta 1-glycoprotein (SP-1) in human serum with the Kone Progress clinical chemistry analyser, using a commercially available antiserum. The absorbance was measured at 340 nm 5 min after addition of antiserum. The assay range was 3-250 mg/l. Over this range the CV for between-day precision was below 6%. Bilirubin up to 160 mumol/l, haemoglobin up to 2 g/l and lipaemia up to 320 mg/l did not interfere. The reference interval in maternal serum at the 15th week of gestation, was 13 to 46 mg/l with a median of 25 mg/l (n = 78) and that of the 16th week was 6 to 60 mg/l with a median of 28 mg/l (n = 78). Comparison of results obtained by two commercially available radio-immunoassays and by the present method shows acceptable correlation. Rapid and reproducible, the immunoturbidimetric method is suitable for use in routine determination of SP-1.

Female↗
PubMed1990

Interference by human anti-mouse antibodies in CA 125 assay after immunoscintigraphy: anti-idiotypic antibodies not neutralized by mouse IgG but removed by chromatography.

Falsely increased concentrations of the ovarian carcinoma-associated antigen, CA 125, were measured by a monoclonal antibody (MAb)-based double determinant immunoradiometric assay (IRMA) in patients who developed antibodies to mouse immunoglobulins (IgGs) after receiving injections of the same MAb as is used in the CA 125 IRMA. Addition of undiluted mouse serum or purified mouse IgG to the assay mixture failed to eliminate the falsely increased CA 125 concentrations in most of the samples, owing to the presence of anti-idiotype antibody. Because of their anti-idiotypic nature, the human anti-mouse antibodies (HAMAS) had only little effect on other immunometric assays, and this effect could be completely eliminated by addition of mouse IgG. To eliminate the effect of HAMA on the CA 125 assay, we studied the ability of various chromatographic methods to separate the interfering HAMA from CA 125. For measuring HAMA in serum and chromatographic fractions we developed a time-resolved fluoroimmunoassay. Adequate separation of CA 125 and HAMA was achieved by affinity chromatography of patients' sera with solid-phase Protein A, Protein G, cation-exchange chromatography on Mono S, and gel filtration on Superose 6. These results demonstrate that the interference can effectively be removed by rather simple chromatographic procedures.

Animals↗
PubMed1989

Liquid-chromatographic determination of acetylated hemoglobin.

In this liquid-chromatographic assay for acetylated hemoglobin in human blood, glycated hemoglobins in hemolysates are first removed by affinity chromatography on boronate-agarose columns. Acetylated hemoglobin in the nonretained fraction is determined by cation-exchange chromatography. The absorbance of the effluent is monitored at 415 nm. The mean within-assay CV was 8.5%, the between-assay CV 17%. The mean proportion of acetylated hemoglobin in 20 pregnant, nondiabetic women was 1.9%, and in 17 alcoholics it was 2.7%. Rapid and reproducible, this method is suitable for use in routine determination of acetylated hemoglobin.

Acetylation↗
PubMed1988

Reaction of a tumour-associated trypsin inhibitor with serine proteinases associated with coagulation and tumour invasion.

The inhibition of six serine proteinases by a tumour-associated trypsin inhibitor (TATI) was studied using synthetic peptide substrates. Physiological concentrations of TATI inhibited the amidolytic activities of trypsin, plasmin, urokinase and tissue plasminogen activator (tPA). Chymotrypsin, kallikrein and thrombin were also inhibited, but by much higher concentrations of TATI. The ability of TATI to inhibit trypsin, plasmin, urokinase and tPA suggests that it has a role in proteolytic processes in vivo involving these enzymes.

Aprotinin↗
PubMed1988

Crystal structure, thermal behaviour, protonation and mass spectroscopic studies of racemic 4-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole hydrochlorides.

The crystal structure, thermal behaviour, mass spectrum and protonation of 4-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole (medetomidine) hydrochloride have been investigated. The title compound crystallizes in both hydrated and anhydrous forms, and their structures have been determined by three-dimensional X-ray structure analysis. The crystals of the anhydrous form are monoclinic and those of the hydrated form (containing one hydrate water molecule) are triclinic with unit-cell dimensions: a = 23.861(9), b = 7.721(4), c = 22.037(9) A, beta = 140.20(4) degrees, Z = 8, and space group C2/c, and a = 7.841(4), b = 8.380(3), c = 12.743(6) A, alpha = 93.66(3), beta = 102.90(3), gamma = 116.85(3) degrees, Z = 2, and space group P1, respectively. Thermal decomposition of the title compound has been interpreted from the TG, DTG and DSC curves with the help of mass spectrometry. Medetomidine hydrochloride monohydrate decomposes in four stages. The first is dehydration at 45-100 degrees C, the second is evaporation of HCl and medetomidine base at 200-320 degrees C, and the third and fourth are decomposition at 340-570 degrees C. The protonation constant is 7.04 in aqueous 0.1 M NaClO4 (25 degrees C).

Adrenergic alpha-Agonists↗
PubMed1987

Urinary dolichol--a new marker of alcoholism.

Urinary dolichol levels of 31 skid-row alcoholics and 49 alcoholics entering a detoxification unit were compared to those of 51 nonalcoholic controls (social drinkers). The mean urinary dolichol content as related to urinary creatinine was significantly (p less than 0.001) higher in the two groups of alcoholics than in the controls. In this material the sensitivity of increased urinary dolichol in the detection of alcoholism was 68% as compared to 44% sensitivity of serum gamma-glutamyltransferase. The percentage of false-positives in the control group was 3.9%. Urinary dolichol is suggested as a potential tool for the detection and follow-up of alcohol abuse.

Adult↗
PubMed1987

Liquid-chromatographic determination of beta 2-microglobulin, alpha 1-acid glycoprotein, and albumin in urine.

We report a reversed-phase "high-performance" liquid-chromatographic assay for beta 2-microglobulin, alpha 1-acid glycoprotein, and albumin in urine. The urine samples are chromatographed on a 15 X 3.2 mm C18-column with a solvent gradient between two mixtures: 1 mL of trifluoroacetic acid per liter of water and 1 mL of trifluoroacetic acid per liter of acetonitrile. The proteins are detected at 218 nm. The useful lower limit of sensitivity for quantification is 0.1 micrograms of each protein in 100-microliters injected samples, corresponding to 1 mg of protein per liter of urine. The linear measuring range extends from 0.1 to 100 micrograms of protein for each peak. Mean analytical recoveries ranged from 92 to 100%. The mean within-assay CV was 7.5%, the between-assay CV 15%. Comparison of results with those obtained by immunoturbidimetry and radioimmunoassay shows acceptable correlation. Reproducible and rapid with low operational cost, this method is suitable for use in routine screening and quantification of urinary proteins.

Albuminuria↗
PubMed1986

Liquid-chromatographic determination of hemoglobin A2.

In this liquid-chromatographic assay for hemoglobin A2 (Hb A2) in human blood, the blood samples are hemolyzed by dilution and the hemolysates are chromatographed on a weak cation-exchanger with a solvent gradient of a buffer with two different ionic strengths. The absorbance of the effluent is monitored at 405 nm. The retention time of Hb A2 is less than 10 min. The mean within-assay CV was 1.6%, the between-assay CV 4.9%. I describe the effects of various column dimensions and sample preparation methods on the separation of Hb A2. The normal reference interval (for 54 healthy adults) was 1.3 to 3.0%. A comparison between results by a minicolumn method and by the present method is performed. Rapid and reproducible, this method is suitable for use in routine determination of Hb A2.

Chromatography, High Pressure Liquid↗
PubMed1986

Liquid-chromatographic determination of dolichols in urine.

A reversed-phase "high-performance" liquid chromatographic assay for dolichols-18, -19 and -20 in urine is described. Dolichols are extracted from urine by using C18 cartridges and are chromatographed with a mobile phase consisting of 2-propanol/methanol, the effluent being monitored at 210 nm. The useful lower limit of sensitivity for quantification is 4 pmol (5 ng) of each dolichol per 5-microL injection, corresponding to 1.6 nmol (2 ng) per liter of urine. Heneicosaprenol is satisfactory as the internal standard. Peak heights and the amounts of dolichols applied to the column are linearly related from 4 to 110 pmol. Mean analytical recovery was 71%. For three different concentrations the mean within-assay CV was 6.4%, the between-assay CV 11%. The normal reference interval of total dolichols found for healthy adults was 17-101 micrograms/24 h (n = 30) or 1.9-11 micrograms per millimole of creatinine (n = 39). I determined the distribution of the main dolichols in urine and applied the assay also for samples from alcoholics.

Adult↗
PubMed1985

The role of carbohydrates in the radioimmunoassay of human low-molecular-mass kininogen.

The immunoreactivity of human low-molecular-mass kininogen from Cohn plasma fraction IV was investigated after deglycosylations and carbohydrate modifications by radioimmunoassay using the conformation-specific antiserum. Removal of all sialic acids, 44% of amino sugars and 63% of neutral sugars did not alter the immunoreactivity of the protein but the periodate-treated concanavalin A fractions showed strikingly diminished immunoreactivity. A conformational change could account for the observed effect of periodate on the decreased reactivity of the protein in radioimmunoassay. Externally added carbohydrates had no effect on immunoreactivity. The results suggest that the carbohydrate part of kininogen is not involved in the immunoreactivity although it accounts for the observed lectin-binding heterogeneity.

Animals↗
PubMed1985

Liquid-chromatographic determination of total hydroxyproline in urine.

A reversed-phase "high-performance" liquid chromatographic assay for total hydroxyproline in urine is described. The urine samples are hydrolyzed overnight with acid, evaporated, solubilized, and derivatized with 4-dimethylaminoazobenzene-4'-sulfonyl chloride. The derivatives are chromatographed with a solvent gradient consisting of sodium acetate buffer and acetonitrile, the effluent being monitored at 436 nm. The useful lower limit of sensitivity for quantification is 13 pmol of hydroxyproline per 5-microL injection, corresponding to 33 mumol/L of urine. Either glutamine or cysteic acid is satisfactory as the internal standard. Peak heights and the amounts of hydroxyproline applied to the column are linearly related from 13.3 to 266 pmol. Mean analytical recovery was 83%. For four different concentrations the mean within-assay CV was 9.0% and the between-assay CV 12%. The normal reference interval found for 31 healthy adults was 31 to 177 mumol/24 h per square meter of body surface. We compared results for 10 samples from patients.

Adult↗