Allergen skin prick testing in early childhood: reproducibility and prediction of allergic symptoms into early adulthood.

OBJECTIVE: To assess the predictive value of skin prick testing in early childhood on subsequent allergic symptoms up to adult age. STUDY DESIGN: A cohort of 200 unselected healthy newborns was prospectively followed from birth to 20 years of age. Of them, 163 (82%) were reassessed at age 5 years, 150 (76%) at age 11 years, and 164 (83%) at age 20 years with a skin prick test that included 11 common allergens. On the basis of clinical examination and structured interview, the occurrence of atopic dermatitis, allergic rhinoconjunctivitis, recurrent wheezing, and symptoms of food hypersensitivity were recorded at each of the follow-up visits. RESULTS: The reproducibility of skin prick test positivity at age 5 years was 100% at ages 11 and 20 years, ie, none of the skin prick-positive subjects turned negative during the follow-up. Gaining of new sensitizations to aeroallergens was common. Skin prick test positivity at age 5 years predicted allergic symptoms at ages 11 (sensitivity 28%, specificity 94%) and 20 years (sensitivity 23%, specificity 91%) but not atopic dermatitis. CONCLUSIONS: Skin prick test positivity at age 5 years strongly predicts later skin prick test positivity and is associated with respiratory symptoms, ie, allergic rhinoconjunctivitis and recurrent wheezing, at ages 11 and 20 years. However, skin prick test negativity at age 5 years does not exclude sensitization and allergic symptoms at a later age.

Age-related effects of increased ambient pressure on discrimination reaction time: A study in 105 professional divers at 6.0 atm abs.

We investigated 105 professional divers using a computerized visual discrimination trial (Cognitrone) to measure the effects of ambient pressure on reaction times. The possible improvement in performance due to practice was anticipated, and the trials were carried out four times prior to pressurization in a hyperbaric chamber. The effect of increased ambient pressure was measured at 6.0 and 1.9 atm abs, and the potential for residual effects was tested after decompression. The results of our study indicate that repeated testing had a systematic influence on the measured time values. The effects of learning, which were independent of diver age, may have independently influenced response times. Exposure to 6.0 atm abs modified the systematic pattern of learning and was associated with increased reaction times. There were also age-related differences in response times associated with exposure to increased ambient pressures. Younger divers were more susceptible to elevated ambient pressure, evidenced by increased response times at 6 atm abs relative to their older colleagues. One out of every four of the younger divers could be considered susceptible to inert gas narcosis (ION) when an increase of one standard deviation/1SD (> 19%) or more in discrimination reaction time is used as an indicator. ION susceptibility appears independent of body composition and physical fitness. The slowed response speed experienced at 6.0 atm abs was of short duration and returned to baseline immediately with decompression. Our results suggest that IGN is demonstrated by an impaired learning process and decreased response speed and that some younger divers appear more susceptible.

Reaction test revealed impaired performance at 6.0 atm abs but not at 1.9 atm abs in professional divers.

In order to evaluate the effects of ambient pressure on reaction and movement times we investigated 60 professional divers by a computerized test (Reaction Test). The experiments were carried out four times in a hyperbaric chamber: prior to pressure, at 6.0 and 1.9 atm abs and after decompression. Reaction time varied from 202 to 443 milliseconds (275 +/- 42 ms), but the individual levels remained similar. The reaction time increased between precompression and 6.0 atm abs (p < 0.05), decreased between 6.0 and 1.9 atm abs (p < 0.05) and remained at the original level at 1.9 and 1.0 atm abs after decompression. Ten divers had an increase of more than 1SD in the reaction time at 6.0 atm abs. The number of mistakes was small and not influenced by elevation of pressure. Further, the movement time remained unchanged throughout the experiment. We conclude that the response time increases due to ambient pressure and the increase in simple reaction time is detectable in professional divers at 6.0 atm not at 1.9 atm abs. At the same time accuracy stays constant. We speculate that our findings are caused by nitrogen narcosis in some divers.

Body dissatisfaction and body mass in girls and boys transitioning from early to mid-adolescence: additional role of self-esteem and eating habits.

BACKGROUND: In the transition from early to mid-adolescence, gender differences in pubertal development become significant. Body dissatisfaction is often associated with body mass, low self-esteem and abnormal eating habits. The majority of studies investigating body dissatisfaction and its associations have been conducted on female populations. However, some evidence suggests that males also suffer from these problems and that gender differences might already be observed in adolescence. AIMS: To examine body dissatisfaction and its relationship with body mass, as well as self-esteem and eating habits, in girls and boys in transition from early to mid-adolescence. METHODS: School nurses recorded the heights and weights of 659 girls and 711 boys with a mean age of 14.5 years. The Rosenberg Self-Esteem Scale and the Body Dissatisfaction subscale of the Eating Disorder Inventory were used as self-appraisal scales. Eating data were self-reported. RESULTS: The girls were less satisfied with their bodies than boys were with theirs (mean score (SD): 30.6 (SD 12.2) vs. 18.9 (SD 9.5); p < 0.001). The girls expressed most satisfaction with their bodies when they were underweight, more dissatisfaction when they were of normal weight and most dissatisfaction when they had excess body weight. The boys also expressed most satisfaction when they were underweight and most dissatisfaction when they had excess body weight. The boys reported higher levels of self-esteem than did the girls (mean (SD): 31.3 (4.8) vs. 28.0 (5.9); p < 0.001). The adolescents self-reporting abnormal eating habits were less satisfied with their bodies than those describing normal eating habits (mean (SD): 33.0 (12.9) vs. 21.2 (10.2); p < 0.001). CONCLUSIONS: Body mass, self-esteem and eating habits revealed a significant relationship with body dissatisfaction in the transitional phase from early to mid-adolescence in girls and boys, but significant gender differences were also found.

Unaltered blood coagulation and platelet function in healthy subjects exposed to acute hypoxia.

INTRODUCTION: Acute hypoxia has been suspected to cause blood coagulation and platelet activation. Our aim was to study blood coagulation and platelet function during a short hypoxic exposure. METHODS: Healthy nonsmoking men (N = 10) inhaled a normobaric hypoxic gas mixture containing 8% of oxygen (92% nitrogen) for 7 min via a face mask. Venous blood was collected 5 min before and during the 5 to 7 min of hypoxia exposure (i.e., pretest and hypoxia samples, respectively) while monitoring arterial oxygen saturation (SaO2) with pulse oximetry. Blood sampling was completed in 2 min and the face mask was removed. Venous epinephrine and norepinephrine, complete blood counts, and a panel of coagulation markers were analyzed. Platelet aggregation induced by ristocetin, adenosine diphosphate (ADP), arachidonic acid, and thrombin receptor activating peptide was studied with Multiplate and shear force-dependent functions with PFA-100R (collagen/epinephrine and collagen/ADP cartridges), both assays in whole blood. RESULTS: During hypoxia, SaO2 declined from 98 to 58% (ranges 97-99% vs. 42-85%), while heart rate increased from 69/min to 94/min (SD 11 vs. SD 13). Venous epinephrine and norepinephrine levels also increased. This short hypoxia induced minor but uniform increases in red cells, reticulocytes, and leukocytes and decreases in platelet counts. Plateletfunctions and prothrombin time, APTT, thrombin time, D-dimer, fibrinogen levels or von Willebrand factor (VWF), antithrombin, factor V (FV) or FVIII activities did not change. DISCUSSION: Profound acute hypoxia failed to affect blood coagulation or platelet functions in healthy individuals.

Cord serum immunoglobulin E as a risk factor for allergic symptoms and sensitization in children and young adults.

Early markers of atopic predisposition are needed for targeting allergy preventive measures to high-risk infants. An elevated cord serum immunoglobulin E (CS-IgE) level is considered a risk factor for subsequent allergy in childhood. However, the previous studies have not assessed the predictive value of CS-IgE in a follow-up extended to adulthood. We aimed at clarifying whether CS-IgE is useful in predicting subsequent atopic manifestations up to age 20 yr. A cohort of 200 unselected, full-term newborns were prospectively followed up from birth to age 20 yr. The CS-IgE level was successfully measured in 190 subjects at birth. The subjects were re-examined at ages of 5, 11 and 20 yr with assessment of the occurrence of allergic symptoms during the preceding year, skin prick testing and measurement of serum total IgE. An elevated CS-IgE level was associated with allergic symptoms and skin prick test positivity at age 5 yr (p = 0.03 and 0.01), with allergic rhinoconjunctivitis at age 20 yr (p = 0.04) and with an elevated serum total IgE at ages of 11 and 20 yr (p = 0.02 and 0.01). The sensitivity of CS-IgE, i.e. the probability of an elevated CS-IgE in an infant who subsequently develops atopy, in predicting skin prick test-verified atopy at ages of 5 and 20 yr was 50% and 26%, respectively. The combination of elevated CS-IgE and positive family history of allergy was strongly associated with subsequent atopic manifestations. Nevertheless, it showed a reduced sensitivity as compared to CS-IgE or family history of allergy. We conclude that an elevated CS-IgE level predicts subsequent atopy up to age 20 yr.

Maternal smoking behavior, background and neonatal health in Finnish children subsequently placed in foster care.

OBJECTIVE: The purpose of this study was to investigate retrospectively neonatal health and maternal background among a sample of children taken into custody and placed in foster care and to investigate the relation between medical and social risk in the neonatal period. METHOD: The data-linkage study combined two registries: the Finnish Medical Birth Registry (MBR), from January 1, 1987 to December 31, 1989, and the Finnish Child Welfare Registry (CWR) from January 1, 1987 to December 31, 1997 using personal identification numbers (n=1,668). As controls all Finnish children born in 1987 were chosen (n=59,727). Infant neonatal health was estimated using the following indicators: birth-weight and birth-length, birth-weight by gestational age, 1-minute Apgar scores, and discharge age from the nursery. Maternal background characteristics included maternal age, parity, marital status, number of antenatal visits at maternity clinics and smoking during pregnancy. RESULTS: We found that the 1,668 children in the study had a lower birth-weight and birth-length, shorter gestational age, lower 1-minute Apgar scores and later discharge from the nursery than the population-based controls. The proportion of teen-age mothers was about four times higher and the proportion of unmarried women was twice as high. A majority of the women (56%) reported smoking during pregnancy, compared with only 15% of the population-based comparisons. Children subsequently taken into custody had poorer health at the time of birth than other children and these differences could only partly be explained by the differences in smoking habits during pregnancy. The women in the study made use of the free health controls at maternity clinics as much as the population-based comparisons. CONCLUSIONS: Our findings indicate that social and medical risks are related in the neonatal period. Since almost all mothers visit maternity clinics, there are possibilities for early intervention.

A comparison of simple reaction time, visual discrimination and critical flicker fusion frequency in professional divers at elevated pressure.

INTRODUCTION: Inert gas narcosis (IGN) impairs cognitive performance and some divers are more susceptible to IGN than others. We compared the sensitivity of two reaction time tests to detect changes in performance at pressure and compared these results with critical flicker fusion frequency (CFF) changes at the same ambient pressures. METHODS: The study assessed simple reaction time (RT), mean time correct of the discrimination reaction time (MTC) and CFF in 30 professional divers breathing air at 101 kPa and 608 kPa in a hyperbaric chamber. RESULTS: RT and MTC increased at 608 kPa by 5.1 ± 9.4% (P = 0.04) and 7.3 ± 12.3% (P = 0.01) respectively. RT decreased to pre-compression level after decompression and MTC decreased to a level lower than pre-compression (P < 0.001) values. CFF increased by 2.5 ± 2.8% (P < 0.001) at 608 kPa. CFF decreased to pre-compression level after decompression. An increase in CFF was inversely correlated with a decrease in RT (r = 0.38, P = 0.04) and in MTC (r = 0.43, P = 0.02) at 608 kPa. CONCLUSIONS: Response speeds of the same subjects were impaired in both reaction time tasks at 608 kPa, whereas CFF increased at depth. An association between changes in response times and changes in CFF suggests that divers susceptible to IGN may also be susceptible to the effects of elevated oxygen partial pressure. If this holds true, the future selection of professional divers could be improved by the use of simple cognitive tests.

The effects of increased pressure, variation in inspired gases and the use of a mask during dry chamber dives on salivary cortisol in professional divers.

INTRODUCTION: Stress activates the hypothalamic-pituitary-adrenal axis resulting in measurable changes in hormone levels in blood or saliva in humans. We aimed to find out if professional divers expressed any change in salivary cortisol levels during a simulated dive to 608 kPa (50 metres' sea water) in a hyperbaric chamber. Furthermore, we investigated the effect of wearing a mask or modifying the breathing gas during decompression. METHODS: We investigated 89 Navy and Coast Guard male divers. The divers were randomised into three groups for decompression by inspired gas and the use of a mask. The saliva samples were collected before and approximately 3 minutes after the hyperbaric test. RESULTS: Salivary cortisol levels decreased from a mean (SD) of 16.0 (8.1) mmol per L pre-dive to 10.3 (5.0) mmol per L post-dive (P < 0.01). Cortisol values did not relate to the anthropometric and physical fitness characteristics of the divers or to increased pressure, variation in inspired gases or the use of a mask. The individual variation in cortisol values was large. CONCLUSIONS: This finding is in line with previous studies demonstrating large individual variations in salivary cortisol. Our findings suggest that professional divers are well adapted to these hyperbaric conditions. However, there continues to be a need to identify divers sensitive to stress caused by diving and the hyperbaric environment.

Pubertal upregulation of erythropoiesis in boys is determined primarily by androgen.

OBJECTIVES: To study the relative roles of androgens and the growth hormone-insulin-like growth factor I (GH-IGF-I) system in the regulation of erythropoiesis in boys during puberty. STUDY DESIGN: We treated 23 boys with constitutional delay of puberty with low-dose testosterone (T), in combination with either a potent aromatase inhibitor, letrozole (Lz; 2.5 mg/d), or placebo (P). The study design was randomized, double-blinded, and placebo-controlled between the treated groups. Treatment with T + Lz was associated with high T and low IGF-I concentrations, whereas treatment with T + P resulted in moderately increased T and high IGF-I concentrations. RESULTS: The blood hemoglobin concentration increased by 1.6 g/dL in T + Lz-treated boys, despite their low IGF-I concentrations. The estimated red blood cell volume increased more in T + Lz-treated than in T + P-treated boys (349 vs 174 mL, respectively, P = .01). Serum T concentrations during the treatment period correlated with the 12-month increments in hemoglobin and red blood cell volume. The changes in blood hemoglobin concentration and RBC in T + Lz-treated boys were similar to those we observed in a population of normal adolescent boys in the late stages of puberty. CONCLUSIONS: The pubertal increase in hemoglobin concentration in boys is related to direct androgen effects.

Squalene and noncholesterol sterols in serum and lipoproteins of children with and without familial hypercholesterolemia.

Squalene and noncholesterol sterols, e.g. lathosterol and plant sterols, the respective markers of cholesterol synthesis and absorption, are transported with cholesterol in serum lipoproteins. Their concentrations and ratios to cholesterol in serum and lipoproteins have not been carefully compared, especially in children and in marked hypercholesterolemia. Thus, we measured these variables with gas-liquid chromatography in 18 children with and 29 without familial hypercholesterolemia, all aged 5-17 y. Concentrations of most noncholesterol sterols were higher in serum, LDL, and intermediate density lipoprotein in the children with than those without familial hypercholesterolemia. Despite accumulation of noncholesterol sterols mainly in LDL (75% in familial hypercholesterolemia and 55% in non-familial hypercholesterolemia, p < 0.001), their ratios were mostly similar in serum and lipoproteins of the two groups. The ratios of squalene and lathosterol were higher in VLDL and intermediate density lipoprotein, whereas in LDL that of lathosterol was lower than the respective serum values in both groups. Absorption marker sterol ratios were highest in HDL in both groups. Thus, even though the ratios of noncholesterol sterols to cholesterol in serum reflect, in general, synthesis and absorption of cholesterol, their ratios in different lipoproteins could give additional information of cholesterol metabolism.

Red cell and plasma plant sterols are related during consumption of plant stanol and sterol ester spreads in children with hypercholesterolemia.

OBJECTIVE: To show whether the ratios of squalene and cholesterol precursor sterols to cholesterol and cholestanol and plant sterols to cholesterol change differently in plasma and especially in the red cells of hypercholesterolemic children during consumption of plant stanol and sterol ester spreads. STUDY DESIGN: In a randomized, double-blind, crossover study, hypercholesterolemic children (n = 23) consumed low-fat plant stanol and sterol ester spreads for 5-week periods separated by a 5-week washout period. Plasma and red cell lipids, squalene, and noncholesterol sterols were measured before and at the end of each period. RESULTS: The plant stanol and sterol ester spreads lowered plasma total (-9% and -6%, respectively) and low-density lipoprotein (-12% and -9%) cholesterol but had no effect on red cell cholesterol, high-density lipoprotein cholesterol, or plasma triglycerides. The ratios of plasma and red cell sitosterol and campesterol to cholesterol decreased by 32% to 36% (P <.001) with the plant stanol ester and increased by 40% to 52% (P <.001) with the sterol ester spread. CONCLUSIONS: Consumption of plant sterols increases and consumption of plant stanols decreases the ratios of plant sterols to cholesterol in red cells of hypercholesterolemic children proportionately to the respective changes in plasma.