Search PubMed⌕ Search

Biomedical subjects

U Turpeinen

Publications and source records attributed to U Turpeinen.

At least 37 records · Page 2Linked to original sources
PubMed1999

Low insulin-like growth factor (IGF-1) in the cerebrospinal fluid of children with progressive encephalopathy, hypsarrhythmia, and optic atrophy (PEHO) syndrome and cerebellar degeneration.

PURPOSE: In patients with progressive encephalopathy, hypsarrhythmia, and optic atrophy (PEHO) syndrome, the pathophysiology underlying early progressive cerebellar and brainstem degeneration and severe epilepsy is unknown. Because insulin-like growth factor (IGF)-1 has been shown significantly to promote survival of cerebellar neurons, we wanted to see if the IGF system played a role in the pathogenesis of cerebellar atrophy. METHODS: We used a sensitive enzyme immunoassay kit for measuring cerebrospinal fluid (CSF) IGF-1 and insulin-like growth-binding protein (IGFBP)-3 in four groups of patients: PEHO syndrome patients (eight), PEHO-like patients (seven), age-matched controls (31), and patients with other types of cerebellar atrophy (11). RESULTS: Patients with PEHO syndrome and those with other progressive, degenerative cerebellar diseases had lower levels of CSF IGF-1 than the controls with other neurologic diseases. The CSF IGF-1 also allowed us to differentiate the "true" PEHO patients from the "PEHO-like" patients (those with similar clinical symptoms but without the typical neuroophthalmologic or neuroradiologic findings). The concentrations of IGFBP-3 did not significantly differ in any of the patient or control groups studied. CONCLUSIONS: CSF IGF-1 levels might be used as a marker of the degeneration of neurons in specific areas.

Atrophy↗
PubMed1998

Combined laboratory and diary method for objective assessment of menstrual blood loss.

BACKGROUND: To develop an objective measurement system for menstrual blood loss applicable in clinical practice. METHODS: One hundred and fifty-six patients were enrolled in a randomized trial of the treatment of menorrhagia in all five gynecology departments of the university teaching hospitals in Finland. Correlation between venous blood hemoglobin concentration (Hb) and absorbance at 564 nm (A564) was investigated in experiments with blood samples. Amount of collected menstrual blood and menstrual diary data were analyzed. RESULT: Hb concentration and A564 of the blood were linearly correlated (r=0.99). One hundred and fifty-four women (99%) returned used sanitary protection and menstrual diaries. On average, 12% (range 0-57%) of menstrual blood was lost during collection. The median amount of blood recovered from sanitary protection was 89 ml (range 14-724 ml), with 58% (n=90) of the women exceeding 80 ml per cycle. When the spilled blood was taken into account, the corresponding figures were 104 ml (range 15-724 ml) and 66% (n= 101). CONCLUSIONS: The spectrophotometric measurement of venous blood in the conventional alkaline hematin method can be replaced by measurement of Hb concentration. All blood incompletely collected should be recorded. Objective measurement of menstrual blood loss can be applied in routine clinical practice.

Adult↗
PubMed1997

Maternal serum screening for Down's syndrome on population basis.

BACKGROUND: The favorable attitude among the public towards prenatal diagnostics in Finland allowed us to start a trial on population basis when screening for Down's syndrome by maternal serum markers and age was introduced. METHODS: Screening by maternal serum markers for Down's syndrome was offered to all 17,200 pregnant women in the Helsinki area during the study period of 2.5 years. Screening due to advanced maternal age, 37 years or more, was continued as previously, and 1133 pregnant mothers used this option. Alpha-fetoprotein, human chorionic gonadotrophin, and during the first year also unconjugated estriol were used as markers. RESULTS: The uptake of serum screening was 84%. The proportion of false positive results i.e. risk for Down's syndrome, 1:350 or more at term, was initially 5.7%. After ultrasound scan 4.1% of the mothers remained 'screen positive'. The amniocentesis or chorionic villus sampling uptake was 98.4%. Ten out of eighteen cases of Down's syndrome were detected by maternal serum screening, sensitivity 56%, 95% CI 31-79%. Other chromosomal abnormalities were found in three cases, and there were four cases of mosaicisms confined to the placenta. These were trisomies 16, 7 and 2, and tetraploidy. Elevated serum alpha-fetoprotein was found initially in 0.7% of the cases. One case of congenital nephrosis of the Finnish type and ten other, mainly structural, abnormalities were detected by high AFP. CONCLUSIONS: The screening was well received by the mothers. The detection rate of 56% is in the same range as in previous studies. Ultrasound scan before the test would effectively lower the false positive rate caused by incorrect timing.

Adult↗
PubMed1997

Urinary excretion of iohexol as a marker of disease activity in patients with inflammatory bowel disease.

BACKGROUND: Increased intestinal permeability of water-soluble contrast medium during an intestinal follow-through is found in patients with active Crohn's disease in the small bowel. METHODS: Urinary excretion of the water-soluble X-ray contrast medium iohexol was measured after oral administration in patients with inflammatory bowel disease and in healthy controls. The patients were grouped on the basis of disease activity and location and extent of intestinal involvement. RESULTS: Urinary excretion of iohexol was significantly higher in patients with active disease than in patients with quiescent disease or in healthy controls (P = 0.005), and it correlated positively with activity indices and with the extent of the disease. CONCLUSION: The intestinal permeability of iohexol is significantly increased in patients with active inflammatory bowel disease in the small bowel and in the colon, whereas the permeability of patients with inactive disease is similar to that in healthy controls. We suggest that urinary excretion of iohexol can be used as a marker of disease activity in patients with inflammatory bowel disease.

Administration, Oral↗
PubMed1997

Determination of urinary free cortisol by HPLC.

We here report a reversed-phase HPLC method for the determination of free cortisol in human urine, using methylprednisolone as the internal standard. Before chromatography, samples were extracted with a C18 solid-phase extraction column and the steroids were separated on a LiChrospher 100 C18 column with a mobile phase of methanol/acetonitrile/water (43/3/54 by vol). Linearity, precision, and accuracy of the method were established. The detection limit was 10 pmol of cortisol, and total CVs were < 8%. With various solid-phase extraction columns the recovery of cortisol was 36-97%; recovery of the internal standard was 43-85%. Study of interference by 6 other steroids and metabolites and 24 drugs showed that carbamazepine and digoxin partly overlapped with cortisol, but this interference could be reduced by modification of the mobile phase. The HPLC method was compared with an RIA and an automated immunoassay method. The results obtained by HPLC averaged 40% of the RIA values.

Calibration↗
PubMed1995

Separation of hemoglobin acetaldehyde adducts by high-performance liquid chromatography-cation-exchange chromatography.

A HPLC-based method was developed to provide a simple way to study changes to hemoglobin induced by acetaldehyde in vitro. This method distinguished 18 human hemoglobin fractions including a new acetaldehyde-induced fraction HbA1ach3. The method consists of a Poly CAT A cation-exchange column and a stepwise salt and pH gradient, with a total analysis time of 31 min. The formation of acetaldehyde adducts was studied by incubation of hemoglobin with different Ach concentrations (5-1000 microM) and different incubation times (0-48 h). Physiological (5-250 microM) Ach concentrations induced increases mainly in 3 known fractions: HbA1ach1, HbA1prec, and HbA1d3; plus, it caused the formation of a new fraction, HbA1ach3. The specificity of the changes to acetaldehyde was studied by incubation of hemoglobin with glucose and acetylsalicylic acid. HbA1ach3 was the only acetaldehyde-induced hemoglobin fraction which was not also increased by glucose and acetylsalicylic acid treatment. The formation of HbA1ach3 showed a dose and time dependence on acetaldehyde incubations. Dialyzation and reduction experiments showed that HbA1ach3 is a stable adduct of hemoglobin, and incubation with purified HbAO showed that HbA1ach3 is an adduct of HbAO. The within-run and between-run coefficients of variation for HbA1ach3 (0.83% of total hemoglobin) were 10.8 and 15.1%, respectively, and the analytical recovery was 82-97%. These results indicate that in addition to the new, acetaldehyde-specific fraction HbA1ach3, several other types of hemoglobin adducts were formed with acetaldehyde. The current method might be useful in clarifying the relationships between hemoglobin and acetaldehyde in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetaldehyde↗
PubMed1995

Two alpha-chain hemoglobin variants, Hb Broussais and Hb Cemenelum, characterized by cation-exchange HPLC, isoelectric focusing, and peptide sequencing.

We here report the characteristics of two rare alpha-chain hemoglobin (Hb) variants. The variants were found during quantification of HbA1c by cation-exchange HPLC with the Diamat glycohemoglobin analyzer. They were further characterized by isoelectric focusing and PolyCAT A cation-exchange chromatography. The structure of the abnormal Hbs was established by amino acid analysis after separation of the globin chains by reversed-phase chromatography, digestion with trypsin, separation of the peptides by reversed-phase chromatography, and amino acid sequencing. These studies showed that the two variants were Hb Broussais [alpha 90 (FG2)Lys-->Asn] and Hb Cemenelum [alpha 92 (FG4)Arg-->Trp].

Adolescent↗
PubMed1995

Three assays for glycohemoglobin compared.

Using 123 specimens, we compared the concordance of three different methods for determining glycohemoglobin (GHb): the Diamat (Bio-Rad Laboratories), an automated analyzer measuring HbA1c by cation-exchange chromatography; an assay with the IMx analyzer (Abbott Laboratories), based on boronate affinity binding; and an HPLC method measuring HbA1c by cation-exchange chromatography on a PolyCAT A column (PolyLC Inc.). The Pearson's correlation coefficient between PolyCAT A and Diamat was 0.900 +/- 0.038 (mean +/- 2 SD) and between PolyCAT A and IMx, 0.857 +/- 0.042. However, up to twofold differences were seen in some samples. The proportion of GHb was consistently lower with the PolyCAT A method than with the other two assays, apparently because of better separation of HbA1c from nonglycated coeluting forms of Hb. The difference in glycation percentage between the PolyCAT A and Diamat methods is 2-3% over the whole concentration range. These results point to the limitations of Diamat as a reference method to be used to calibrate other methods for determining HbA1c. Further, a switch from one method to another is likely to cause considerable problems in the clinical follow-up of certain patients.

Autoanalysis↗
PubMed1994

Phenotypic variation and magnetic resonance imaging (MRI) in Salla disease, a free sialic acid storage disorder.

Salla disease (SD) is a recessively inherited lysosomal storage disorder particularly common in the Finnish population. Patients with SD are normal at birth, but develop psychomotor delay and ataxia during the first year of life. Phenotypic variation of SD is wide, ranging from severely disabled children to mentally retarded adults capable of living under sheltered conditions. In the present study four unusually severely affected patients were investigated by detailed clinical examination, magnetic resonance imaging (MRI) and analysis of the excretion of free sialic acid in urine. MRI study, reported here for the first time, revealed a similarly defective myelination pattern in seven patients. The myelination process seemed to cessate at the level of an infant of a few months of age. Genetic linkage study of the families of the severely affected patients suggested linkage to the recently discovered SD locus on the long arm of chromosome 6. Locus heterogeneity therefore is an unlikely explanation of the phenotypic variation in SD.

Adolescent↗
PubMed1994

Carbohydrate-deficient transferrin as an alcohol marker among female heavy drinkers: a population-based study.

Carbohydrate-deficient transferrin (CDT) has previously been reported to be an excellent marker of male alcoholics. Less is known of its efficiency among women and especially of early-phase alcohol abuse in nonselected populations. The present population-based study examined the diagnostic value of CDT among consecutive women, including 13 teetotallers, 135 social drinkers (mean alcohol consumption 45 +/- 34 g/week), and 57 nonalcoholic heavy drinkers (197 +/- 97 g/week). Sixty-two women with a well-documented history of chronic alcoholism (942 +/- 191 g/week) were also studied, as well as 36 pregnant women used as a reference group. Two weeks of abstinence among 11 alcoholics was followed. The CDT (containing part of isotransferrin with pI = 5.7, 5.8, and 5.9) was separated by anion exchange chromatography and assayed by radioimmunoassay. In the whole material, CDT correlated significantly with alcohol consumption (r = 0.43, p < 0.001) but not with conventional markers (gamma-glutamyltransferase, AST, ALT, and mean corpuscular volume). The CDT values of alcoholics (34 +/- 20 units/liter) were significantly (p < 0.001) higher than those of teetotallers (19 +/- 6 units/liter), social drinkers (20 +/- 6 units/liter), or pregnant women (16 +/- 3 units/liter). Heavy drinkers also had higher values (25 +/- 13 units/liter), but the difference did not reach statistic significance. The specificity of CDT was on the level of conventional markers when the cut-off value was increased from 26 to 29 units/liter. At a specificity of 95%, CDT found 19% of the heavy drinkers and 52% of the alcoholics; the best traditional marker, AST, with a specificity of 97%, found 7% and 56%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Determination of human tumour necrosis factor-alpha (TNF-alpha) by time-resolved immunofluorometric assay.

We have developed a 'sandwich'-type time-resolved immunofluorometric assay (IFMA) for tumour necrosis factor alpha (TNF-alpha) using two monoclonal antibodies (mAb) and the streptavidin/biotin (SAB) system. In this simple and fast streptavidin/biotin IFMA (SAB-IFMA) we used streptavidin coated wells to which we added biotinylated mAb for 3 h. After washing, the serum sample was added and incubated for 2 h followed by washing. Another monoclonal europium-labelled tracer antibody was added and incubated for 1 h, the wells were washed and the fluorescence of Eu measured. We tested various assay conditions in order to optimize the assay for sensitivity and measuring range. Purification of the labelled antibody by hydrophobic interaction chromatography was found to be essential to improve sensitivity. With a sample volume of 50 microliters the detection limit was 6 ng l-1 and the analytical range large, i.e. 10,000-fold. The median concentration in serum from healthy subjects was 12 ng l-1 and the reference range < 39 ng l-1. The mean analytical recovery in plasma was 76% and in serum 83%. Separation of serum by gel filtration and assay of TNF-alpha in fractions showed that the assay also measured the high molecular weight (MW) form of TNF-alpha, apparently corresponding to its complex with soluble receptors. Advantages of our SAB-IFMA were high sensitivity and low consumption of mAb. The assay performance of the SAB-IFMA was compared to two commercially available enzyme immunoassays also using the SAB system.

Antibodies, Monoclonal↗
PubMed1993

Optimization of a time-resolved immunofluorometric assay for tumor-associated trypsin inhibitor (TATI) using the streptavidin-biotin system.

We have developed two 'sandwich'-type time-resolved immunofluorometric assays (IFMA) for tumor-associated trypsin inhibitor (TATI) using monoclonal and polyclonal antibodies. In the standard assay the monoclonal antibody was immobilized onto the walls of polystyrene microstrip wells and the polyclonal reagent was labeled with a europium chelate. We tested various assay conditions in order to optimize the assay for sensitivity and measuring range. Purification of the labeled antibody by hydrophobic interaction chromatography was found to be the most important single factor affecting sensitivity. Assay sensitivity and range were also improved by acid treatment of the solid phase antibody. To improve the sensitivity further the streptavidin/biotin (SAB) system was incorporated into the IFMA technique. In this simple and fast streptavidin/biotin IFMA (SAB-IFMA) we used streptavidin-coated wells to which we added biotinylated monoclonal antibody and a serum or urine sample. After incubation for 1.5 h and washing, the polyclonal europium-labeled tracer antibody was added. After incubation for 1 h the wells were washed and the Eu fluorescence measured. The assay performance of the SAB-IFMA was compared to the standard IFMA and radioimmunoassay (RIA). The detection limit was 0.05 microgram/l and the analytical range 3000-fold. The mean analytical recovery was 101%. Other advantages of the SAB-IFMA were high sensitivity and the low amounts of monoclonal antibody required, only 1/50 of that used in the standard IFMA.

Antibodies, Monoclonal↗
PubMed1993

Concentrations of pancreatic secretory trypsin inhibitor (PSTI), acute phase proteins, and neopterin in Crohn's disease. Comparison with clinical disease activity and endoscopical findings.

The usefulness of pancreatic secretory trypsin inhibitor (PSTI) as a marker of chronic inflammation was studied in patients with Crohn's disease. Pancreatic secretory trypsin inhibitor was compared with other laboratory tests (C-reactive protein, orosomucoid, and urinary neopterin), for evaluation of disease activity as measured by a clinical scoring system and endoscopical findings. The clinical utility of the tests was compared by four different methods. All tests showed significant differences in laboratory values between inactive and severely active disease. Using earlier established cut-off values PSTI showed the best combination of sensitivity and specificity for differentiation between inactive and severely active disease. When the efficacy of the test was compared by ROC-curve analysis, neopterin and orosomucoid produced the best combination of sensitivity and specificity, but for both assays the earlier established cut-off levels were too high for optimal separation between active and inactive disease. There was a poor agreement between endoscopically and clinically determined disease activity and the laboratory tests correlated better with clinical activity. The present study shows that serum PSTI reflects changes in the clinical activity of Crohn's disease equally well as C-reactive protein, which previously has been found to be an useful index of disease activity.

Adult↗
PubMed1993

Simultaneous assay of alpha-fetoprotein and free beta subunit of human chorionic gonadotropin by dual-label time-resolved immunofluorometric assay.

We developed a simple, rapid two-step dual-label assay for the noncompetitive determination of alpha-fetoprotein (AFP) and beta subunit of human chorionic gonadotropin (hCG beta) in serum. Monoclonal antibodies to detect AFP and hCG beta were labeled with europium (Eu) and samarium (Sm), respectively. Highly fluorescent chelates were developed by using the Delfia enhancement principle. The detection limits for AFP and hCG beta were approximately 0.02 kIU/L and approximately 0.2 IU/L, respectively. The within-run precision was < 5% over the whole range of AFP (1-500 kIU/L) and hCG beta (1-200 IU/L) concentrations tested. Cross-reaction of intact hCG was < 0.03%. The AFP concentrations determined with the dual-label assay correlated well with those obtained by Delfia AFP single-label kit. The concentrations of hCG beta were in good agreement with recently published data. Storing the serum samples for 24 h or 1 week at room temperature increased the hCG beta concentration by 4% and 26%, respectively. At 35 degrees C this dissociation of hCG increased 30-40-fold. Repeated freezing and thawing had no effect on the hCG beta concentration.

Antibodies, Monoclonal↗
PubMed1992

Determination of fetal hemoglobin by time-resolved immunofluorometric assay.

We have developed a "sandwich"-type time-resolved immunofluorometric assay (IFMA) for fetal hemoglobin (HbF) in hemolysates from adults and newborns, amniotic fluid, and plasma, based on a polyclonal and a monoclonal antibody against human fetal hemoglobin. Microtiter wells are coated with polyclonal capture antibody, and the gamma-chain-specific monoclonal tracer antibody is labeled with a europium chelate. In a simple and fast assay procedure, prediluted hemolysates are incubated in the microtiter wells first with capture antibody for 1 h and, after washing, for 1 h with tracer antibody. The wells are washed and the fluorescence of europium is measured. The mean analytical recovery is 102% and results by IFMA agreed well with values obtained by high-performance liquid chromatography. The analytical range of IFMA is large and well suited for clinical purposes. The detection limit of the assay is 0.2 microgram/L and the measuring range extends to 500 micrograms/L.

Amniotic Fluid↗