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T Laitinen

Publications and source records attributed to T Laitinen.

At least 55 records · Page 3Linked to original sources
PubMed1998

Hay fever--a Finnish nationwide study of adolescent twins and their parents.

BACKGROUND: Like other atopic diseases, hay fever is known to cluster in families. This clustering is due either to effects of a shared family environment or to genetic inheritance. By comparing the occurrence of hay fever among monozygous (MZ) and dizygous (DZ) twin pairs, we were able to estimate the contribution of genetic and environmental factors in the development of hay fever. METHODS: A questionnaire mailed to a nationwide sample of 2483 families with 16-year-old twins furnished data for the cumulative incidence of physician-diagnosed hay fever among these adolescents and their parents. RESULTS: Among the 1765 twin pairs with data available for analysis, hay fever was reported for 14.1% of boys (95% CI=12.4-15.8%) and 10.0% of girls (95% CI=8.6-11.4%). The MZ twin pairs (probandwise concordance rate=60.3%, 95% CI =52-68%) were significantly more concordant for hay fever than were DZ twin pairs (31.5%, 95% CI=26-36%). Genetic factors accounted for 74-82% of the interindividual variability in liability to hay fever, variation in shared family environment for 7% at most, and unique (individual) environment for 18%. CONCLUSIONS: Familial occurrence of hay fever is mainly due to genes predisposing to the trait. Environmental exposures shared in common by family members but varying between families appear to account for at most a modest proportion of the variability in risk of developing hay fever.

Adolescent↗
PubMed1998

Age and gender dependency of baroreflex sensitivity in healthy subjects.

We evaluated the correlates of baroreflex sensitivity (BRS) in healthy subjects. The study consisted of 117 healthy, normal-weight, nonsmoking male and female subjects aged 23-77 yr. Baroreflex control of heart rate was measured by using the phenylephrine bolus-injection technique. Frequency- and time-domain analysis of heart rate variability and an exercise test were performed. Plasma norepinephrine, epinephrine, insulin, and arginine vasopressin concentrations and plasma renin activity were measured. In the univariate analysis, BRS correlated with age (r = -0.65, P < 0.001), diastolic blood pressure (r = -0.47, P < 0.001), exercise capacity (r = 0.60, P < 0.001), and the high-frequency component of heart rate variability (r = 0.64, P < 0.001). There was also a significant correlation between BRS and plasma norepinephrine concentration (r = -0.22, P < 0.05) and plasma renin activity (r = 0.32, P < 0.001). According to the multivariate analysis, age and gender were the most important physiological correlates of BRS. They accounted for 52% of interindividual BRS variation. In addition, diastolic blood pressure and high-frequency component of heart rate variability were significant independent correlates of BRS. BRS was significantly higher in men than in women (15.0 +/- 1.2 vs. 10.2 +/- 1.1 ms/mmHg, respectively; P < 0.01). Twenty-four percent of women > 40 yr old and 18% of men > 60 yr old had markedly depressed BRS (< 3 ms/mmHg). We conclude that physiological factors, particularly age and gender, have significant impact on BRS in healthy subjects. In addition, we demonstrate that BRS values that have been proposed to be useful in identifying postinfarction patients at high risk of sudden death are frequently found in healthy subjects.

Adult↗
PubMed1998

Importance of genetic factors in adolescent asthma: a population-based twin-family study.

Gene-environment interactions and inheritance of asthma were studied in 16-yr-old twins and their parents who participated in the nationwide Finnish Twin Cohort Study. Between 1991 and 1994, questionnaires, including a question on physician-diagnosed asthma, were mailed to the members of 2,483 twin families. The individual response rate ranged from 82 to 93%. Information on parental asthma status allowed the genetic modeling of asthma data in two different groups of twins. In families where one of the parents was asthmatic, as much as 87% of the variation in susceptibility to asthma in twins was explained by genetic factors. On the other hand, for twins whose parents were unaffected, a model including environmental effect alone was sufficient to explain the development of asthma. Genetic influences could not be totally excluded, but their role was significantly smaller. These results indicate that the presence of asthma in successive generations is more likely caused by shared genes than shared environmental risk factors; however, substantial heterogeneity among families may exist. Genetic analysis, especially among the families with an obvious familial component in development of asthma, may enhance the chances of revealing the pathogenetic mechanisms

Adolescent↗
PubMed1997

Genetic control of serum IgE levels and asthma: linkage and linkage disequilibrium studies in an isolated population.

Immunoglobulin E (IgE) concentration in serum is elevated in atopic diseases such as asthma. A large genomic region on chromosome 5 has previously been implicated in the control of IgE levels and bronchial hyperreactivity and may, therefore, harbor genes predisposing to asthma. In an effort to confirm this linkage and to delimit the critical region, we took advantage of an isolated founder subpopulation in Finland to study genetic linkage and haplotype associations. Sixteen polymorphic markers, including the Interleukin-4 and -9 genes (IL4, IL9), were physically ordered and genotyped in 157 nuclear families. Genetic linkage studies involving sib- and cousin-pair analyses found no evidence of genetic linkage between markers in 5q and either serum IgE levels or asthma. Haplotype association studies were also performed. Although initial inspection suggested the possibility of linkage disequilibrium in the region of IL9, we developed a rigorous permutation test for assessing association and determined that the association was no greater than would be expected by chance. Sequence analysis of the IL9 gene in three patients sharing a possibly conserved haplotype revealed a T113M coding polymorphism, but this variant showed no association with either serum IgE levels or asthma. We conclude that allelic variation at chromosome 5q31 is not likely to contribute to inheritance of serum IgE levels or the development of asthma in this Finnish subpopulation.

Adolescent↗
PubMed1997

Are three-dimensional surface-shaded SPET images better than planar and coronal SPET images in the assessment of regional pulmonary perfusion?

Although single photon emission tomographic (SPET) imaging has been shown to be more sensitive than planar imaging in the diagnosis of pulmonary embolism, it has yet to be used routinely in clinical practice. The aims of this study were (1) to compare a new three-dimensional surface-shaded version of SPET (3-D SPET) with conventional planar imaging and coronal SPET slices, and (2) to evaluate observer agreement among these three modalities in the assessment of regional pulmonary perfusion. Compared with a consensus score (based on revised PIOPED criteria) of 29 cases, including nine with a clinical diagnosis of pulmonary embolism, 3-D SPET showed the highest number of normal scans, suggesting better specificity than planar or coronal SPET images. Five observers evaluated the three image sets twice within a 3-6 month period. Agreement with the consensus score was slightly better for the second reading and the average perfect agreement was 71-76%. No one image set was superior to any other in this respect. In conclusion, the number of normal scans using 3-D SPET is significantly greater relative to planar and coronal SPET scans as defined by the consensus view. Observer agreement rates are very similar with all three modalities.

Adult↗
PubMed1997

HLA-G polymorphism in Finnish couples with recurrent spontaneous miscarriage.

HLA-G is a class I major histocompatibility complex gene that is expressed in cytotrophoblasts at the materno-fetal interface. It has been suggested that HLA-G could play a key role in materno-fetal immunological interactions during pregnancy. To investigate whether there is an association between HLA-G locus and recurrent spontaneous miscarriage, HLA-G alleles were determined by a PCR-RFLP method in 38 couples with recurrent spontaneous miscarriage and in 26 random control couples. In this series parental HLA-G sharing, extended HLA-G/A haplotypes and the frequencies of the HLA-G alleles were similar in the two groups. Thus, our data suggest that there is no detectable relation between susceptibility to recurrent spontaneous miscarriage and HLA-G locus.

Abortion, Habitual↗
PubMed1997

Hay fever, asthma and number of older siblings--a twin study.

BACKGROUND: It has been suggested that allergic sensitization is inversely related to the number of siblings in the family. OBJECTIVES: To study whether a similar relation can be observed for hay fever and asthma among Finnish adolescents in a population with relatively low prevalence of atopic diseases. METHODS: A questionnaire mailed to a nationwide sample of 1849 families with 16-year-old twins assessing the cumulative incidence of doctor-diagnosed hay fever and asthma among the adolescents and the number of older siblings in the family by parental report. RESULTS: The cumulative incidence of hay fever was significantly lower among the adolescents with three or more older siblings (3.9%, 95% CI = 1.2-6.5%) compared with adolescents with fewer older siblings (12.7%, 95% CI = 11.4-14.0%). There was no difference in the cumulative incidence of asthma among the adolescents according to the number of older siblings in the family. CONCLUSIONS: Large number of older siblings appears to be protective against the development of hay fever.

Adolescent↗
PubMed1996

Covalent binding of three epoxyalkyl xylosides to the active site of endo-1,4-xylanase II from Trichoderma reesei.

The three-dimensional structures of endo-1,4-xylanase II (XYNII) from Trichoderma reesei complexed with 4,5-epoxypentyl beta-D-xyloside (X-O-C5),3,4-epoxybutyl beta-D-xyloside (X-O-C4), and 2,3-epoxypropyl beta-D-xyloside (X-O-C3) were determined by X-ray crystallography. High-resolution measurement revealed clear electron densities for each ligand. Both X-O-C5 and X-O-C3 were found to form a covalent bond with the putative nucleophile Glu86. Unexpectedly, X-O-C4 was found to bind to the putative acid/base catalyst Glu177. In all three complexes, clear conformational changes were found in XYNII compared to the native structure. These changes were largest in the X-O-C3 complex structure.

Benzoates↗
PubMed1996

Trace metal analysis of coal fly ash collected plain and on a quartz fibre filter.

A simple, uniform procedure has been developed for microwave-based digestion of fly ash samples collected from the hoppers of an electrostatic precipitator (ESP), or collected from flue gases on a heat-resistant quartz fibre filter and for subsequent atomic absorption spectrometric analysis of trace metals (Be, Cd, Co, Cr, Cu, Mn, Ni, Pb, V and Zn). HNO(3), HCl, HF and mixtures have been tested as digestion acids. The combination of HNO(3) and HF has been found to be efficient for the digestion of fly ash samples with and without quartz fibre filter material. In spite of the complicated matrix, results with satisfactory accuracy and precision (relative standard deviation below 10% for most of the elements) have been obtained. In the case of analysis of fly ash together with a quartz fibre filter, the calibration curve has to be determined by standard addition to a blank solution containing a dissolved blank quartz fibre filter.

Journal Article↗
PubMed1996

Mercury adsorption on gold surfaces employed in the sampling and determination of vaporous mercury: a scanning tunneling microscopy study.

To clarify the mechanism of mercury adsorption on gold surfaces thin epitaxial gold films have been exposed to trace amounts of gaseous mercury under laboratory conditions for different periods of time. The changes in the surface morphology of the thin films caused by the exposure have been studied by scanning tunneling microscopy (STM). The evolution of the surface structures with time has been also investigated, in the course of a few days after the exposure. The adsorption of mercury on the gold surfaces has caused drastic changes in the morphology of the surfaces. Pits and islands of 2 to 30 nm in diameter have appeared on the surface, their size and density per unit area depending on the amount of exposure to mercury. The formation of pits and islands followed a certain path of events.

Journal Article↗
PubMed1993

A set of MHC haplotypes found among Finnish couples suffering from recurrent spontaneous abortions.

PROBLEM AND METHOD: The role of major histocompatibility complex (MHC) genes in the etiology of recurrent spontaneous abortion (RSA) was studied by analyzing the polymorphism of several, at least 14, immunogenetically important MHC genes either by serological or molecular methods in 56 Finnish RSA couples, and in 29 infants born to these families during the follow-up period of two years after the abortions. RESULTS: The haplotype analysis showed that the RSA couples had significantly increased sharing of MHC fragments, compared to the control families. Furthermore, the MHC risk markers for abortions defined 12 different, extended MHC haplotypes that were found in a significantly higher proportion among persons in the RSA group (45%) than in the controls (11%). However, neither of these observations associated with the reproductive success of the study couples. CONCLUSIONS: The results suggest that extended MHC haplotypes, disadvantageous for reproduction, exist in some isolated populations, such as the Finns.

Abortion, Habitual↗
PubMed1993

Foeto-maternal compatibility in HLA-DR, -DQ, and -DP loci in Finnish couples suffering from recurrent spontaneous abortions.

The polymorphism of Major Histocompatibility Complex (MHC) class II genes DRB, DQA, DQB, and DPA was studied by TaqI Restriction Fragment Length Polymorphism (RFLP) in recurrent spontaneous abortions (RSA). The study group consisted of 35 primary abortion (PA) couples (no children) and 15 secondary abortion (SA) couples (1-2 children before abortions). We found no increase in DR-DQ compatibility between the mother and the foetus in the Finnish RSA group. In contrast to findings in some other populations, foeto-maternal incompatibility was increased in the PA group. Thus, our results do not support the theory that increased MHC class II compatibility is a cause of abortions as such. The Finns are a small and relatively isolated population with a unique gene inheritance. Thus, one can speculate that, if the human MHC class II is in the linkage with disadvantageous 'fertility genes', and these genes might nonetheless still be clustered in only a few MHC haplotypes among the Finns. This would be the reason, that DR-DQ sharing is not seen. The presence of rare HLA alleles, such as DR2 and DR6, among the aborters also supports this. In addition, this study extends our previous findings on MHC class III in regards to PA and SA couples differing immunogenetically from each other. In MHC class II, this was most obvious in the DPA1 locus. The vast majority of SA women were heterozygous for the two most common DPA1 alleles (14.0 kb and 13.5 kb), resulting in significantly smaller chances for a DPA1 mismatched foetus to occur in the SA group than in the controls or in the PA women.

Abortion, Habitual↗
PubMed1992

Tumour necrosis factor B gene polymorphism in relation to complotype in couples with spontaneous abortions and in control families.

NcoI restriction fragment length polymorphism (RFLP) of the tumour necrosis factor B (TNFB) gene gives two allelic fragments of 5.5 and 10.5 kb, corresponding to the TNFB*1 and TNFB*2 alleles, respectively. The frequencies of these alleles were analysed in 121 healthy Finns and 56 Finnish couples suffering from recurrent spontaneous abortions (RSA). In the healthy Finns the frequency of TNFB*1 was 37% and that of TNFB*2 63%, of which the frequency of TNFB*1 was significantly increased compared with the Danish population. No deviation was seen between the RSA couples and the Finnish controls. TNF genes are located in major histocompatibility complex class III region close to complement (BF, C4A and C4B) genes. Some complotypes associated most often with the TNFB*1 (S01, S30, S02) and some (S31, F320) with the TNFB*2 allele in the healthy Finns. The combination of the TNFB and the C4 'null' allele differed between the RSA couples and the Finnish controls.

Abortion, Habitual↗
PubMed1992

Major histocompatibility complex located complement C4 and steroid 21-hydroxylase gene rearrangements in couples with recurrent spontaneous abortions.

Major Histocompatibility Complex (MHC) class III located complement C4 and steroid 21-hydroxylase (21OH) genes, which form various deletion and duplication units, were studied by TaqI Restriction Fragment Length Polymorphism (RFLP) in 58 Finnish couples who suffered recurrent spontaneous abortions (RSA). The gene rearrangements found in the RSA couples did not differ from those in the controls.

Abortion, Habitual↗
PubMed1991

Increased frequency of complement C4 'null' alleles in recurrent spontaneous abortions.

Typings for major histocompatibility antigens HLA A, B, C and DR and for complement C4A, C4B and factor B were performed for 59 Finnish couples experiencing at least three consecutive recurrent spontaneous abortions (RSA). Forty-one of them were primary abortion (PA) couples with no children and 18 were secondary abortion (SA) couples who had one or two children before abortions. HLA sharing in A and B loci was slightly but significantly increased (15%, P less than 0.05) among RSA couples compared to the controls, as was DR sharing among SA couples compared to PA couples (50% versus 22%, P less than or equal to 0.05). The most interesting new finding, however, was the statistically significant increase of complement C4 functionally silent, i.e. C4 'null', alleles in RSA couples. C4 is a duplicated gene and its products differ in their functions in the complement cascade. C4A null alleles were equally increased in PA wives and in PA husbands (32%, P less than or equal to 0.05) compared to the controls (18%) and C4B null alleles in SA wives (56%, P less than or equal to 0.05) and in SA husbands (50%) compared to the controls (29%). Therefore, the offspring of RSA couples have a significantly increased risk of inheriting several null alleles. The majority, 95% (P less than 0.001) of PA couples and 83% of SA couples, had at least one C4A or C4B null in their phenotypes compared to 66% among Finnish controls.

Abortion, Habitual↗