Autism spectrum traits and visual processing in young adults with very low birth weight: the Helsinki Study of Very Low Birth Weight adults.

Visual processing problems may be one underlying factor for cognitive impairments related to autism spectrum disorders (ASDs). We examined associations between ASD-traits (Autism-Spectrum Quotient) and visual processing performance (Rey-Osterrieth Complex Figure Test; Block Design task of the Wechsler Adult Intelligence Scale-III) in young adults (mean age=25.0, s.d.=2.1 years) born preterm at very low birth weight (VLBW; <1500 g) (n=101) or at term (n=104). A higher level of ASD-traits was associated with slower global visual processing speed among the preterm VLBW, but not among the term-born group (P<0.04 for interaction). Our findings suggest that the associations between ASD-traits and visual processing may be restricted to individuals born preterm, and related specifically to global, not local visual processing. Our findings point to cumulative social and neurocognitive problems in those born preterm at VLBW.

Gm allotypes influence the production of IgG3 but the effect is age-dependent.

Serum concentrations of IgG3 were found to be higher in Gm-f-positive (= b-positive) than in f-negative individuals except in young children. Young children aged 3-4 months had a mean concentration of 0.24 g/l of IgG3 regardless of allotype. The concentration gradually rose with age in f-positive individuals to a geometric mean of 0.56 g/l in adults but it remained essentially unchanged in f-negative people. A corresponding allotype effect was seen in influenza-specific antibody responses. While the total IgG response (mainly IgG1) was equally strong in f-positive and in f-negative patients, f-positive (= b-positive) patients produced more IgG3 antibodies than f-negative patients. The difference between geometric mean values of opposite homozygotes (f/f versus f-negative) was 2.3-fold (p = 0.0113). This finding indicates that the b-positive gamma-3 allele is more productive than the g-positive allele.

Lack of clinical exacerbations in adults with chronic asthma after immunization with killed influenza virus.

The effects of immunization with killed influenza virus vaccine were assessed by comparison with placebo in a double-blind study of 318 adult patients with chronic asthma. The patients were randomly allocated to active vaccine and placebo. No difference was observed in peak expiratory flow rate or in clinical symptoms of bronchial obstruction between the groups receiving active vaccine and placebo during the first week after immunization. The data were analyzed separately for age, sex, duration of the disease, hypersensitivity to aspirin (acetylsalicylic acid), atopic status, patients with a history of attacks of asthma induced by viral infections, patients with a diurnal variation of baseline peak expiratory flow of 20 percent or more, and patients receiving continuous oral steroid medication, but none of these factors seemed to predict any short-term adverse effects of vaccination. Follow-up for eight months after the vaccination revealed no differences in asthmatic symptoms between the patients treated with active vaccine and those receiving placebo. The antiviral antibody response to vaccination was normal. The possible protection provided by the vaccination against exacerbation of asthma induced by influenza could not be evaluated, since the influenza epidemic expected during the season failed to occur in Finland. It is concluded that immunization with killed influenza vaccine is safe and is not associated with any significant side effects in adult patients with chronic asthma.

Serum HI antibody and protection against influenza: a follow-up survey at community level of three epidemics caused by different H3N2-variants.

Serial blood specimens from Rh-negative pregnant women sent to laboratory for Rh antibody testing were stored and used for influenza investigations. The study period covered three epidemics, each caused by a different variant of influenza A (H3N2) virus. The relationship between pre-epidemic haemagglutination inhibiting (HI) antibody level against the epidemic virus and serological evidence of infection was analysed. Titre associated with protection was very similar in the three epidemics. In 1973-74 the influenza A epidemic had an exceptional course characterized by prolonged duration. The study revealed data on the rate of infection in one age and sex category that are difficult to obtain using standard indicators of influenza epidemiology.

Antigenic analysis of intraepidemic variants of influenza A (H3N2) viruses by hyperimmune rat antisera.

Hyperimmune rat antisera prepared against 5 recent antigenic variants of influenza A (H3N2) viruses were studied for haemagglutination inhibiting (HI) antibodies to the homologous and the heterologous viruses. The ratios of homologous to heterologous reactions varied from one animal to another in immunizations with each of the immunogens. Some antisera exhibited a ratio high enough to allow differentiation of the epidemic variants and demonstration of an intraepidemic heterogeneity of field strains isolated during the outbreak of 1985/86. The variation of cross-reactions of polyclonal antisera may reflect differences in the range of specificities of anti-haemagglutinin antibodies produced by individual animals. The significance of this finding in the classification of influenza A (H3N2) viruses is discussed. Lack of nonspecific inhibitors interfering with the HI test is an additional advantage of hyperimmune rat antisera in typing influenza A and B virus isolates.

Enzyme immunoassay, complement fixation and hemagglutination inhibition tests in the diagnosis of influenza A and B virus infections. Purified hemagglutinin in subtype-specific diagnosis.

The efficacy of enzyme immunoassay (EIA) in detecting diagnostic antibody rises to influenza A and B viruses was compared with complement fixation (CF) and hemagglutination inhibition (HI) tests in 455 patients with an acute respiratory infection. EIA and HI detected significantly more diagnostic antibody rises against influenza A than the CF method (96 and 87 vs. 47, respectively). In the case of influenza B significantly more diagnostic influenza B antibody rises were observed by EIA than by CF or HI (59 vs. 37 and 40, respectively). In most of the cases antibody rises in EIA were found in both IgG and IgA isotypes whereas increases in IgM antibodies were seen less frequently. Purified hemagglutinins (HA) were prepared from influenza A HI- and H3-subtypes and from influenza B viruses and used as antigens in EIA and the results were compared with those of HI. Infections caused by influenza A HI-subtype showed good homologous antibody responses in EIA but heterologous antibody responses to H3-subtype and influenza B HAs were frequently observed. Heterologous responses were clearly less frequent in patients with infections caused by the H3-subtype. Influenza B infections occasionally raised HA antibodies against influenza A H1-subtype but not to the H3-subtype. Interestingly, HI detected these heterologous responses at least as frequently as EIA. When whole viruses were used as antigens in EIA, subtype specificity was not observed and cross-reactions between influenza A and B virus antibodies were found. These observations suggest that, although EIA can show greater diagnostic efficacy over HI and CF methods, HI is still the serological method of choice in determining the causative subtype of influenza A virus infection.

The value of complement fixation and haemagglutination inhibition tests in the diagnosis of influenza A.

Antibody response of 133 influenza A patients from three outbreaks since 1972-73 was analyzed by complement fixation (CF) and haemagglutination inhibition (HI) methods. During the first outbreak, a significant response was more often measured by CF than by HI. During the last outbreak HI appeared more useful than CF for routine serological diagnosis; 23% of cases verified by HI were missed by CF. The poor response of CF antibodies was associated with the high level of pre-infection antibodies.

OS103. Hypertensive disorders during pregnancy and cognitive decline of the offspring up to old age: the helsinki birth cohort study.

INTRODUCTION: Hypertensive disorders affect the fetal developmental milieu and may point to mechanisms by which prenatal adversity is associated with lower cognitive ability in subsequent life. OBJECTIVES: We tested whether hypertensive disorders during pregnancy predict age-related change in cognitive ability in the offspring up to old age. METHODS: Using mothers' blood pressure and urinary protein measurements from the maternity clinics and birth hospitals, we defined normotensive or hypertensive pregnancies in mothers of 398 men, who participated in the Helsinki Birth Cohort 1934-44 Study. The men underwent the Finnish Defense Forces basic ability test twice, first, during compulsory military service at age 20.1 (SD=1.4) years and, then, in a re-test at age 68.5 (SD=2.9) years. The test yields a total score and subscores for tests measuring verbal, arithmetic and visuospatial reasoning. Scores were standardized with a mean of 100 and standard deviation of 15. RESULTS: Men born after pregnancies complicated by a hypertensive disorder, compared with men born after normotensive pregnancies, scored 3.84 (95% Confidence Interval, 0.77 to 6.91) points lower on total cognitive ability at 68.5 years, and displayed a greater decline in total cognitive ability (2.31, 0.23 to 4.39) after 20.1 years. Of the subscores, associations were strongest for arithmetic reasoning. CONCLUSION: Maternal hypertensive disorders in pregnancy predict lower cognitive ability and greater cognitive decline up to old age. Multidisciplinary research is essential in order to uncover the mechanisms linking hypertensive pregnancy disorders with lower cognitive abilities in the offspring.

Neurocognitive abilities in young adults with very low birth weight.

OBJECTIVE: Although severely preterm birth has been associated with impaired neurocognitive abilities in children, follow-up studies in adulthood are scarce. We set out to study whether adults born with very low birth weight (VLBW) (<1,500 g), either small for gestational age (SGA) (birth weight ≤-2 SD) or appropriate for gestational age (AGA), differ in a range of neurocognitive abilities and academic performance from adults born at term and not SGA. METHODS: As part of the Helsinki Study of Very Low Birth Weight Adults, 103 VLBW (37 SGA) and 105 term-born control adults (mean age 25.0, range 21.4-29.7 years) without major neurosensory impairments participated in the follow-up study in 2007-2008. The test battery included measures of general cognitive ability as well as executive functioning and related abilities. Academic performance was self-reported. RESULTS: With adjustment for sex and age, the VLBW group scored lower or performed slower than the control group in some indices of all tests (these mean differences ranged from 0.3 to 0.5 SD units, p ≤ 0.03) and they had received remedial education at school more frequently; however, no differences existed in self-reported academic performance. The differences were evident in both VLBW-SGA and VLBW-AGA groups. Further covariate adjustments for parental education, current head circumference, and head circumference at birth and, in tests of executive functioning and related abilities, adjustment for IQ estimate had minor effects on the results. CONCLUSIONS: In comparison with control adults, VLBW adults scored lower on several neurocognitive tests. Poorer neurocognitive performance is associated with VLBW irrespective of the intrauterine growth pattern.

Body size at birth and cardiovascular response to and recovery from mental stress in children.

Cardiovascular (CV) response to mental stress, a predictor of CV disease risk, may be determined already in utero. However, the underlying mechanisms remain unclear, and previous studies have used adult subjects and neglected CV recovery. We investigated 147 girls and 136 boys aged 8 years who underwent the Trier Social Stress Test for children to determine whether body size at birth is associated with CV activity. Blood pressure (BP), electrocardiogram and impedance-derived indices were recorded and analyzed from continuous measurements using Vasotrac APM205A and Biopac MP150 systems. Among girls, lower birth weight was associated with lower baseline systolic BP (SBP) and diastolic BP (DBP) values (1.9 mm Hg and 1.5 mm Hg per 1 s.d. birth weight for gestational age, respectively), higher SBP and DBP response to mental stress (1.6 mm Hg and 1.1 mm Hg per 1 s.d. birth weight for gestational age, respectively), slower BP recovery and overall higher cardiac sympathetic activity. In contrast, among boys lower birth weight was associated with higher baseline levels of SBP (2.1 mm Hg per 1 s.d. birth weight for gestational age) and total peripheral resistance (TPR), overall lower cardiac sympathetic activity, lower TPR response to mental stress and a more rapid BP and cardiac sympathetic recovery. In boys, the associations with baseline levels and cardiac sympathetic activity became significant only after adjusting for current body size. These sex-specific results suggest that individual differences in childhood CV response to and recovery from mental stress may have prenatal origins. This phenomenon may be important in linking smaller body size at birth to adult CV disease.

Romantic attachment in young adults with very low birth weight - The Helsinki Study of Very Low Birth Weight Adults.

Early attachment relationships from infancy onward contribute to attachment patterns later in life, to the ability to build up close relationships and to well-being in general. Severely preterm birth may challenge the development of these attachment relationships. We studied whether there are differences in attachment patterns related to romantic relationships between young adults (mean age 22.4 years, s.d. 2.2 years) with very low birth weight (VLBW, <1500 g; n = 162) and their peers born at term (n = 172), who completed the Experiences in Close Relationships Questionnaire - Revised. Young adults born at VLBW showed lower attachment-related anxiety than their peers born at term (mean difference -9.5%, 95% CI -16.0 to -2.6) when adjusted for sex, age, parental education and being in a romantic relationship currently. The groups did not differ in attachment-related avoidance. In subgroup analyses, the VLBW women born small for gestational age (SGA, birth weight <-2 s.d.) scored on average 14.8% (95% CI 3.1-26.6) higher than the control women on attachment avoidance. The effects remained after the exclusion of 18 participants with neurosensory deficits. We found no evidence for a compromised attachment pattern in young adults born at VLBW, with a possible exception of women born SGA at VLBW. VLBW adults were rather characterized by a lower level of attachment-related anxiety.