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R Puukka

Publications and source records attributed to R Puukka.

At least 19 recordsLinked to original sources
PubMed2005

Pre-analytical factors and measurement uncertainty.

Pre-analytical factors are an important source of variation or errors in clinical laboratory measurements. Based on the new accreditation standards, medical and laboratory professions now seek to develop tools to deal systematically with these diverse factors. Several obvious pre-analytical uncertainty components were estimated in pragmatic experiments and combined with data on analytical variation and literature knowledge on biological variation, to estimate the measurement uncertainty of most common chemical and haematological examinations in clinical laboratories. The main aim was to assess quality specifications for regional laboratory services. The expanded measurement uncertainties (level of confidence 95%) of serum cholesterol, albumin and potassium remained within 13-16%. The major uncertainty component for cholesterol was biological variation, whereas those for albumin and potassium were sample collection and pretreatment. The measurement uncertainties for serum free thyroxin, thyrotropin and C-reactive protein, 20%, 42% and 125% respectively, were largely due to their biological variation. The measurement uncertainties of basic erythrocyte parameters (erythrocyte count and mean corpuscular volume, blood haemoglobin concentration) were less than 10%. Larger measurement uncertainties were obtained for thrombocyte and leukocyte counts, 24 and 31%, respectively, and for the reticulocyte fraction, 41%.

Adult↗
PubMed1996

The immunoglobulin heavy-chain variable region in insulin-dependent diabetes mellitus: affected-sib-pair analysis and association studies.

We have analyzed immunoglobulin heavy-chain variable-region (VH) polymorphisms and genetic susceptibility to insulin-dependent diabetes mellitus (IDDM) by using a set of polymorphic loci that span approximately 1,000 kb of the VH region on chromosome 14q32. One hundred one Finnish families with at least two children affected with IDDM were studied. Conventional RFLPs determined by hybridization were used, since no microsatellite repeat markers have been available for this gene region. No evidence for linkage between the VH genes and IDDM could be obtained from haplotype-sharing analysis among the 133 diabetic sib pairs. The frequencies of various VH genotypes were also compared between 101 familial IDDM cases and 114 controls derived from the Finnish background population. The distribution of the genotypes at the VH2-B5 locus was significantly different between these groups (P=.004), the 3.4/3.4 genotype being less common in the IDDM cases. In addition, a different genotype distribution at the VH5-B2 locus was observed in the diabetic subjects (P = .022). When the IDDM cases were stratified by presence or absence of the high-risk HLA-DQB1*0302 allele, no differences in VH genotype frequencies were observed between the 0302-positive and 0302-negative cases. In the transmission test for linkage disequilibrium (TDT), no differences were found between the expected and observed frequencies of the transmitted alleles at the VH2-B5 or VH5-B2 locus. In conclusion, significant differences in VH genotype distributions were observed between the familial IDDM cases and the controls, but the observed associations could not be confirmed by the TDT. Haplotype sharing analysis provided no evidence for genetic linkage between the VH gene region and IDDM.

Adolescent↗
PubMed1995

Effect of genetic risk load defined by HLA-DQB1 polymorphism on clinical characteristics of IDDM in children.

Clinical and autoimmune characteristics of 150 diabetic children of mean age 7.8 years (SD 4.1 years) were recorded at clinical manifestation and during the first 2 years of IDDM in order to investigate whether subjects with high risk HLA-DQB1 genotypes differ from those without these risk markers. When comparing subjects with the DQB1*0302/0201, DQB1*0302/x, DQB1*0201/x, or other DQB1 genotypes (x = no protective allele), no differences were found in the age of the subjects at diagnosis, the duration of hyperglycaemic symptoms, or the length of clinical remission. The frequency of islet cell antibodies (ICA) and quantitative serum levels of these antibodies were of the same magnitude in all four groups. During the initial 2 years of IDDM serum C-peptide concentrations were observed to be inversely related to the degree of genetic risk (P < 0.001 in two-way analysis of variance for repeated measures), the lowest C-peptide levels being observed in the group of DQB1*0302/0201 heterozygotes (P < 0.001 vs. DQB1*0201/x; P < 0.01 vs. DQB1*0302/x; P = 0.05 vs. others). On the other hand, the subjects with the DQB1*0201 genotype had the highest serum C-peptide concentrations, the levels being even higher than those of the patients carrying neutral or protective DQB1 genotypes (P < 0.01). These subjects also had lower daily insulin doses and blood glycated haemoglobin A1 (HbA1) levels over the initial 2 years of the disease when compared with the DQB1*0302/0201 heterozygotes (P < 0.05 and P < 0.01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Improved metabolic control in patients with non-insulin-dependent diabetes mellitus is associated with a slower accumulation of glycation products in collagen.

Twenty-one patients with non-insulin-dependent diabetes in poor metabolic control were subjected to intensified therapy, in most cases with insulin, to investigate whether it is possible to slow down the accumulation of advanced glycosylation end products of collagen by improving glycaemic control. Fasting and mean daily blood glucose, serum fructosamine and glycohaemoglobin levels, as well as glycation of collagen were measured before and after 1.5 years of intensified therapy. All these parameters except for fructosamine correlated significantly with fasting blood glucose and glycohaemoglobin when measured before the insulin therapy was started, when the patients had had poor but stable metabolic control for a long period of time. After 1.5 years of intensified therapy the level of glycation of collagen did not significantly correlate with the fasting blood glucose or glycohaemoglobin levels, suggesting that the non-enzymatic glycosylation of collagen reflects a longer period of metabolic control of diabetes than the glycohaemoglobin level. Intensified treatment improved previously poor metabolic control in patients with non-insulin-dependent diabetes, and this improvement was reflected in a decrease in fasting and mean daily blood glucose levels, serum fructosamine and glycohaemoglobin concentrations, and in the level of early products of glycation of collagen. The average content of advanced glycosylation end products of collagen, assayed in terms of collagen-linked fluorescence did not decrease. However, they accumulated more slowly in the patient tercile with the greatest decrease in the level of fasting blood glucose than in the tercile with the smallest decrease, and even a decrease in fluorescence was observed in the patients with the greatest improvement in the metabolic control.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Clinical characteristics and circulating collagen and laminin metabolites in insulin-dependent diabetic children with joint and skin manifestations.

One hundred seventy-four children and adolescents with insulin-dependent diabetes mellitus were examined for joint contractures and skin manifestations in their hands. Joint contractures were found in 52 (29.8%) and skin manifestations in 29 (16.6%) patients. To eliminate the possible confounding effects of age and duration of diabetes on the variables to be studied, patients younger than 7 y and with a duration of diabetes shorter than 3 y were excluded from the subsequent analyses. Of the remaining 108 children, those with joint contractures had lower serum concentrations of the 7-S domain of type IV collagen and the P1 fragment of laminin than the other patients (p = 0.033) but higher mean glycated Hb levels (p = 0.048). A clear association was noted between the occurrence of joint contractures and skin changes (p = 0.007). Background retinopathy was found in six patients (5.6%), three of whom had stage II joint contractures (p = 0.064). The children with skin changes and those with combined joint and skin manifestations more often had insulin-dependent diabetes mellitus in their first-degree relatives (p = 0.038 and p = 0.043, respectively). No difference in relative height was found between the groups. No association could be seen between disease susceptibility antigens in the HLA-D locus and joint or skin manifestations. The lower levels of circulating collagen and laminin metabolites in the diabetic children with joint contractures suggest that these patients are characterized by a reduced turnover of basement membranes in tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

New method for the determination of pancreatic amylase evaluated.

We have carried out a multicenter evaluation of a new reagent carrier for Reflotron, specific for pancreatic amylase where the salivary isoenzyme is inhibited by two specific monoclonal antibodies. This new procedure combines easy handling with low imprecision (median CV less than 3%) in control material, serum, heparinized blood, and plasma) and close correlation (r = 0.991 to 0.999) with established manual and automated methods. The same close correlation was found with values obtained from either venous or capillary finger-stick blood. Salivary amylase up to 54 kU/L (37 degrees C) was inhibited to about 97%. Endogenous interference by hemoglobin, bilirubin, triglycerides, cholesterol, or hematocrit was found to be negligible within a wide range of interferent concentrations. Out of a panel of 28 commonly used drugs it was shown that only two (ascorbic acid and paracetamol), and then only at toxic concentrations, caused a deviation in amylase activity of greater than 10%. From the results of this study we conclude that this new method is suitable for highly precise and accurate measurements of pancreatic amylase in emergency and routine laboratories.

Amylases↗
PubMed1989

Clinical significance of urinary C-peptide excretion in children with insulin-dependent diabetes mellitus.

In order to evaluate the accuracy of urinary C-peptide determination and the clinical significance of C-peptiduria for the early course of insulin-dependent diabetes (IDDM), the rate of urinary excretion of C-peptide was determined in 32 children and adolescents with IDDM and correlated with serum C-peptide concentration, urinary excretion of albumin and beta 2-microgloublin and with the glomerular filtration rate (GFR) measured in terms of the clearance of 99mTc-DTPA. The age of the subjects ranged from 9.1 to 17.1 years (mean 13.1) and the duration of diabetes from 0.3 to 11.9 years (mean 4.6). There was a good correlation between postprandial serum C-peptide concentration and the 24-hour urinary C-peptide excretion rate (r = 0.81; p less than 0.001). GFR and urinary albumin excretion were slightly elevated in the diabetic patients as compared with non-diabetic subjects (p less than 0.05 and p less than 0.001, respectively), but C-peptide excretion was unrelated to the degree of hyperfiltration or albuminuria, neither was there any correlation between the excretion rate of beta 2-microglobulin and C-peptide. Glycaemic control was poorer in the diabetic children who had only trace amounts of C-peptide in their urine (less than 0.05 nmol/m2/24 h) than in those with minimal (0.05-1.0 nmol/m2) or moderate 24-hour urinary C-peptide excretion (greater than 1.0 nmol/m2). It is concluded that urinary C-peptide excretion serves very well to reflect residual beta-cell function and is unrelated to the slight renal hyperfunction and albuminuria often seen in diabetic subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Reduced insulin removal and erythrocyte insulin binding in obese children.

To study the relationship between childhood obesity, weight loss, hyperinsulinaemia and the erythrocyte insulin receptor, we measured the plasma concentrations of immunoreactive insulin (IRI) and C-peptide and the binding of 125I-insulin to erythrocytes in 12 obese children with a mean age +/- SD of 11.4 +/- 2.5 years and a mean relative weight score +/- SD of 4.8 +/- 1.4 and 12 age-matched normal-weight children. Eight obese children were re-evaluated after 1 year's participation in a weight reduction programme. The obese children had higher fasting plasma concentrations of IRI (P less than 0.01) and C-peptide (P less than 0.05) and a lower C-peptide to IRI molar ratio (P less than 0.01) than the normal-weight children. The obese children had in addition a reduced erythrocyte insulin binding (P less than 0.05 or less) over the physiological range of circulating insulin concentration. There was a negative correlation (r = -0.60; P less than 0.01) between the insulin tracer binding and the relative weight. The weight reduction programme resulted in a decrease of 1.0 SD (P less than 0.05) in the mean relative weight score. At the end of the therapy the obese children had lower fasting blood glucose levels (P less than 0.05) and lower plasma IRI concentrations at 90 min (P less than 0.05) after an oral glucose load than at the onset of therapy. There were no significant differences between the insulin binding characteristics at the commencement and at the end of the treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Glucose↗
PubMed1988

Postnatal decrease in insulin binding to erythrocytes in infants of diabetic mothers.

To clarify the role of insulin receptors in the macrosomia and the tendency to hypoglycemia in infants of mothers with insulin-treated diabetes mellitus (IDM) we studied insulin binding in erythrocytes from mixed umbilical blood and from peripheral venous blood collected when the infants were 3-14 days old. Normal infants were matched for gestational and postnatal age. The IDM infants were macrosomic, with significantly higher birth weights relative to gestational age than the control infants. Plasma free insulin concentrations in cord blood were 15-fold higher in the IDM than in the normal infants and more than 3-fold higher in the peripheral venous blood at the median age of 4 days. Hypoglycemia occurred in 12 of the 17 IDM and in none of the normal infants. In umbilical blood insulin binding to erythrocytes was similar in the IDM and normal infants. In both groups insulin binding decreased during the first postnatal weeks, but the decrease was significantly greater in the IDM than in the normal infants. The decrease in insulin binding to erythrocytes was a consequence of decreased receptor affinity as well as decreased receptor concentration in the IDM infants, but was mainly due to decreased receptor concentration in the normal infants. We conclude that insulin binding to its erythrocyte receptor in cord blood in IDM infants is similar to that in normal infants in spite of the simultaneous gross hyperinsulinemia in the IDM infants. The resulting increase in insulin action would then contribute to the tendency toward hypoglycemia and may be partly responsible for the macrosomia in IDM infants. The marked postnatal decrease in insulin binding in IDM infants is a possible explanation for their diminishing risk of hypoglycemia after the first few days of life in spite of persisting hyperinsulinemia.

Birth Weight↗
PubMed1987

Maternal residual beta-cell function and the outcome of diabetic pregnancy.

Preservation of own insulin production (residual pancreatic beta-cell function) has been shown to have a beneficial effect on glycemic control in insulin-dependent diabetic subjects, and its total lack has been suggested to be an independent risk factor during diabetic pregnancy. We studied the influence of residual beta-cell activity on the glucose control and the outcome of pregnancy in 29 diabetic women by sequentially measuring gestational postprandial plasma C-peptide (CPR) levels, diurnal blood glucose curves and blood glycosylated hemoglobin (Hb A1c) and by analyzing the morbidity and mortality of the offsprings. The 9 diabetics with moderate own insulin secretion (CPR levels over 1.0 microgram/l, White classes B and C, later referred to as group I) had significantly better glucose control than the remaining 20 subjects with lower CPR values (White classes C, D and NF, later referred to as group II) (figure 1, table I). There were two intrauterine deaths, both in group II. These deaths (one caused by multiple congenital contracture syndrome and the other by severe intrauterine growth retardation without any evident cause) could not be straightly connected with diabetes. Respiratory distress syndrome was seen in group II only. There was no other significant difference in the neonatal morbidity between the two groups (table II). All mothers of RDS infants were in White class NF where the birthweight was also smaller than in classes B and C. These were the only differences in neonatal morbidity between the White classes (table III). In conclusion, moderate residual beta-cell function seemed to be clinically important in maintaining strict glucose control during gestation.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Glucose↗
PubMed1986

Correlation between umbilical vein blood flow and umbilical blood viscosity in normal and complicated pregnancies.

Umbilical vein blood flow (UVBF) was studied during the last 24 h before delivery using a combination of real-time and Doppler ultrasonic equipment in 64 normal and pathological pregnancies and the results were correlated with the values of whole blood viscosity taken from the umbilical vein after delivery. UVBF was reduced in the subgroup with chronic fetal distress (n = 14) (P less than 0.001) and the hypertensive pregnancies (n = 17) (P less than 0.05), whereas umbilical blood viscosity was increased only in the subgroup with chronic fetal distress (P less than 0.01) as compared with the normal pregnancies (n = 24). A significant positive correlation was observed between the umbilical blood viscosity and haematocrit values in all the groups of patients. UVBF and blood viscosity had a significant negative correlation in chronic fetal distress (P less than 0.001) and in hypertensive pregnancies (P less than 0.05), but not in normal or diabetic pregnancies (n = 9). Thus haemoconcentration leading to increased fetal blood viscosity may act as an aetiological factor in the reduction of UVBF in developing fetal distress.

Blood Viscosity↗
PubMed1986

Levels of some purine metabolizing enzymes in lymphocytes from patients with Down's syndrome.

The activities of a number of purine metabolizing enzymes of erythrocytes and lymphocytes were determined in 18 subjects with Down's syndrome and in 18 age- and sex-matched control subjects. An increase of adenosine deaminase activity (adenosine or deoxyadenosine as substrates) was found in erythrocytes (P less than 0.001) as well as in lymphocytes (P less than 0.001) of Down's syndrome subjects compared to controls. The purine nucleoside phosphorylase activities in lymphocytes and plasma urate concentrations were also significantly higher in Down's syndrome subjects than in controls (P less than 0.001 and less than 0.02, respectively). Adenine phosphoribosyltransferase activities and hypoxanthine-guanine phosphoribosyltransferase activities in lymphocytes were identical in the two groups. In all subjects studied there were positive correlations between the erythrocyte adenosine deaminase activities, lymphocyte adenosine deaminase or deoxyadenosine activities, and plasma urate concentrations (P less than 0.05 in all cases), and between lymphocyte nucleoside phosphorylase and lymphocyte adenosine deaminase or deoxyadenosine deaminase activities (P less than 0.01 and less than 0.05, respectively). The results suggest that increased activities of some purine metabolizing enzymes found in both erythrocytes and lymphocytes may contribute to increased purine degradation and hyperuricemia in subjects with Down's syndrome. In addition, the increased adenosine deaminase and nucleoside phosphorylase activities may be related to the immunological dysfunction found in subjects with Down's syndrome.

Adenine Phosphoribosyltransferase↗
PubMed1986

Residual B-cell function and glycaemic control in diabetic pregnancy.

Serum C-peptide immunoreactivity (CPR), mean blood glucose and blood glycosylated haemoglobin Hb A1c were measured in 23 insulin-dependent diabetic women at 11-12, 23-24, 33-34 and 37-38 gestational weeks in order to elucidate changes in residual B-cell function during pregnancy and their influence on the glycaemic control. CPR values generally increased at the 23-33 gestational weeks, with a significant difference between the mean of the peak values and the mean of the values at the first admission. When the subjects were divided into two groups on the basis of the residual B-cell function at the first admission, the glycaemic control during pregnancy was significantly better in those with higher residual B-cell activity. The overall prevalence of marked residual B-cell activity was higher than previously reported in non-pregnant insulin-dependent diabetic subjects. The results indicate clinically important enhancement in residual B-cell function during pregnancy. The mechanism of this improvement is poorly known although the more strict management of diabetes during gestation may be an important factor.

Adult↗
PubMed1986

Erythrocyte insulin binding in preterm newborn infants.

To characterize the erythrocyte insulin receptor in newborn infants we studied the binding of 125I-insulin to the erythrocytes from 42 preterm infants (14 at birth, 14 aged 2-7 days, and 14 aged 8-16 days) with a mean gestational age of 34.1 wk, and from 32 term infants (16 at birth and 16 aged 2-7 days). The insulin binding to cord blood erythrocytes from preterm infants was significantly higher than that of cord blood cells from term infants and to postnatal cells from preterm as well as term infants. The erythrocytes from preterm infants aged 2-7 days bound more insulin than cells from preterm infants aged 8-16 days. The maximum insulin binding (specific insulin binding at tracer concentration of insulin) correlated negatively with the gestational age both at birth and over the 1st postnatal wk. In the preterm infants there was a strong negative correlation between the maximum insulin binding and postnatal age. The enhanced insulin binding to cord blood erythrocytes from preterm infants was due to both an increased receptor concentration and a high affinity for insulin. The increased affinity persisted over the 1st wk of life. In preterm infants older than 1 wk the insulin binding characteristics were basically similar to those in term newborn infants. In all infants studied the receptor concentration seemed to be postnatal age dependent while the receptor affinity was gestational age dependent. No correlation was found between the insulin binding data and the plasma concentrations of immunoreactive insulin or C-peptide.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Glucose↗
PubMed1984

Evidence of delayed beta-cell destruction in type 1 (insulin-dependent) diabetic patients with persisting complement-fixing cytoplasmic islet cell antibodies.

Forty-four children with Type 1 (insulin-dependent) diabetes (aged 0.7-16.7 years) were observed from diagnosis for cytoplasmic islet cell antibodies and serum C-peptide concentrations. Islet cell antibodies were analysed by indirect immunofluorescence for both conventional IgG and complement-fixing antibodies. Thirty-seven children (84%) were found to be positive for conventional islet cell antibodies at diagnosis, and 21 (48%) remained positive over the observation period. Twenty-six patients (59%) were positive for complement-fixing antibodies at diagnosis and eight remained so during the follow-up period. The serum C-peptide concentrations increased significantly during the first 3 months after diagnosis, after which there was a gradual decrease in the levels. Those children who remained positive for complement-fixing antibodies over the observation period had significantly higher serum C-peptide concentrations on several occasions during the second year and had also a higher integrated serum C-peptide concentration over the initial 2 years than those who became negative for complement-fixing antibodies. These observations suggest that the continuous production of complement-fixing islet cell antibodies in those patients who are positive for these antibodies at diagnosis presupposes the preservation of a sufficient amount of functioning beta cells for antigenic stimulation. These results support the view that the complement-fixing islet cell antibodies reflect ongoing destructive processes in the beta cells.

Adolescent↗
PubMed1984

Physical fitness of children and adolescents with insulin-dependent diabetes mellitus.

The physical working capacity (PWC170) of 84 children and adolescents with insulin-dependent diabetes mellitus (IDDM) and of 94 non-diabetic subjects was measured by a submaximal progressive exercise test. The age of the diabetic subjects ranged from 6.3 to 18.8 years and that of the control subjects from 8.5 to 18.8 years. The PWC170 of diabetic boys was lower than that of non-diabetic boys (p less than 0.01) while no difference was observed between diabetic and non-diabetic girls. PWC170 was inversely related to age (p less than 0.01) and concentration of hemoglobin A1 (p less than 0.025) in diabetic boys but not in diabetic girls. No relationship was observed between PWC170 and duration of diabetes in either boys or in girls. The results indicate that good physical fitness in boys is associated with a better metabolic control. Hence the study indirectly supports previous observations that physical activity improves the metabolic control of IDDM.

Adolescent↗