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At least 1,189 records · Page 66Linked to original sources
PubMed2004

Effect of anti-immunoglobulin E on nasal inflammation in patients with seasonal allergic rhinoconjunctivitis.

BACKGROUND: Binding of allergens to IgE on mast cells and basophils causes release of inflammatory mediators in nasal secretions. OBJECTIVE: The combined effect of specific immunotherapy (SIT) and omalizumab, a humanized monoclonal anti-IgE antibody, on release of eosinophilic cationic protein (ECP), tryptase, IL-6, and IL-8 in nasal secretion was evaluated. METHODS: Two hundred and twenty five children (aged 6-17 years) with a history of seasonal allergic rhinoconjunctivitis induced by birch and grass pollen were randomized into four groups: either birch- or grass-pollen SIT in combination with either anti-IgE or placebo. Complete sets of nasal secretion samples before treatment Visit 1 (V1), during birch- (V2) and grass (V3)-pollen season and after the pollen season (V4) were collected from 53 patients. RESULTS: A significant reduction in tryptase only was seen in the anti-IgE-treated group at V2 (P<0.05) and V4 (P<0.05) compared with the placebo group. During the pollen season, patients with placebo showed an increase of ECP compared with baseline (V2: +30.3 microg/L; V3: +134.2 microg/L, P< 0.005; V4: +79.0 microg/L, P< 0.05), and stable levels of tryptase, IL-6 and IL-8. Treatment with anti-IgE resulted in stable ECP values and a significant decrease of tryptase compared with V1 (baseline): V2: -80.0 microg/L (P< 0.05); V3: -56.3 microg/L, which persisted after the pollen season with V4: -71.6 microg/L (P< 0.05). After the pollen season, a decrease of IL-6 was observed in both groups (V4 placebo group: -37.5 ng/L; V4 anti-IgE group: -42.9 ng/L, P< 0.01). CONCLUSION: The combination of SIT and anti-IgE is associated with prevention of nasal ECP increase and decreased tryptase levels in nasal secretions.

Adolescent↗
PubMed2006

Do skin prick and conjunctival provocation tests predict symptom severity in seasonal allergic rhinoconjunctivitis?

BACKGROUND: In the investigation of seasonal allergic rhinoconjunctivitis (SAR), quantitative skin and conjunctival allergen challenge tests are used to measure individual allergen sensitivity. These tests are reproducible and relate well to prevalence but their relationship to symptom severity is less well established. OBJECTIVE: We wished to determine if quantitative skin prick tests (QSPT) and conjunctival provocation tests (CPTs) using a single grass pollen allergen extract are reproducible and predict symptom severity in SAR. METHODS: We retrospectively analysed data from 91 participants in a previously published randomized placebo controlled study of low dosage allergen immunotherapy who were randomized to receive placebo treatment. We examined the relationship between pre-seasonal QSPT, CPT and SAR symptoms. RESULTS: We found a high level of reproducibility when repeated measures were compared for both the QSPT (P < 0.001) and the CPT (P < 0.001) and moderate correlation (0.49) between the standard skin prick test (SPT) and the QSPT (P < 0.001). We found weak negative correlation (-0.27) between the QSPT and the CPT (P < 0.001). We found no correlation between seasonal symptom, use of rescue medication or quality of life (QOL) scores and pre-seasonal QSPT or CPT. Conclusion In the assessment of seasonal rhinoconjunctivitis, quantitative skin and conjunctival allergen challenge tests are strongly reproducible, although there is no correlation between these tests and seasonal symptom, use of rescue medication or QOL scores.

Adolescent↗
PubMed2005

The roe deer as a model for studying seasonal regulation of testis function.

In mature male seasonal breeders, the circannual cycles of testicular growth and involution involve significant changes in structure and function of both the tubular and interstitial testicular compartment. Roe deer (Capreolus capreolus) are seasonal breeders with a short defined rutting season from mid-July to mid-August and represent a unique non-rodent model for studying testicular functions during the course of a complete reproductive cycle with naturally changing photoperiod. Germ cells and Sertoli cells of the seminiferous tubules and the interstitial Leydig cells all display significant morphological and physiological alterations during the seasonal changes. In contrast to the germ cell population, Sertoli and Leydig cells persist as a numerically constant cell population in the roe deer testis. This report emphasizes the intricate relationship between seasonal cellular differentiation, intratesticular growth factor networks and their impact on the functional dynamics during the seasonal changes in roe deer testis.

Animals↗
PubMed2006

Causes and consequences of adaptive seasonal sex ratio variation in house sparrows.

1. Here we examine how sex ratio variation in house sparrow broods interacts with other demographic traits and parental characteristics to improve the understanding of adaptive significance and demographic effects on variation in sex ratio. 2. The sex ratio in complete broods did not deviate significantly from parity (54.9% males). 3. There was sex-specific seasonal variation in the probability of recruitment. Male nestlings that hatched late in the breeding season had larger probability of surviving than early hatched males. 4. An adaptive adjustment of sex ratio should favour production of an excess of males late in the breeding season. Accordingly, the proportion of male offspring increased throughout the breeding season. 5. A significant nonlinear relationship was present between sex ratio and age of the female. However, there was no relationship between parental phenotype and standardized hatch day that could explain the observed seasonal change in sex ratio. 6. The sex-specific number of offspring recruited by a pair to subsequent generations was closely related to the brood sex ratio. 7. These results indicate an adaptive adjustment of sex ratio to seasonal variation in environmental conditions that affects the offspring fitness of the two sexes differently. Our results also suggest that such a sex ratio variation can strongly influence the demography and structural composition of small passerine populations.

Adaptation, Biological↗
PubMed1997

Seasonal prevalence of ticks and tick-transmitted haemoparasites in traditionally managed N'Dama cattle with reference to strategic tick control in the Gambia.

A survey of tick spatial and seasonal distribution in traditional managed N'Dama cattle over 1 year old was carried out in The Gambia over 16 months. Presence of Anaplasma marginale and Babesia spp. in the blood smears and their antibodies in the serum of same animals were also examined. Tick species, in decreasing order of abundance, were: Boophilus geigy, Rhipicephalus senegalensis, B.decoloratus, Hyalaomma truncatum, H.marginatum rufipes and Amblyomma variegatum. All tick species peaked during the rainy season. Additional B.geigy peaks occurred towards the end of the dry season. The most infested animal body areas were anogenital, udder and abdomen. A.variegatum, Hyalomma spp. and, to a lesser extent, Boophilus spp. showed strong preferences for these anatomical regions. Overall prevalence of A.marginale, B.bigemina and B.bovis haemoparasites were 3.2%, 0.9% and 0.1%, respectively. Peaks of A.marginale and B.bigemina occurred at the end of the rainy season-beginning of the dry season; an additional A.marginale peak was observed at mid-end dry season. Overall antibody seroprevalence were 29.6% for A.marginale, 44.7% for B.bigemina and 5.2% for B.bovis; monthly fluctuations in percentage of seroreactors were limited. Endemic stability for A.marginale and B.bigemina is postulated. Implications of the outcomes are discussed in relation to tick-control strategy in The Gambia.

Anaplasma↗
PubMed1993

Is the allergen-inhalation challenge predictive of the severity of seasonal asthmatic exacerbations?

Fifteen asthmatic patients sensitized to Parietaria pollen were studied. Before the pollen season they underwent an allergen-inhalation challenge which was preceded and followed by a methacholine-inhalation challenge. Pollen count, symptom score, and drug consumption were monitored daily throughout the study. A severity score was obtained by adding symptom score and drug consumption. Patients underwent a third methacholine challenge during the pollen season, after they had been exposed to a high atmospheric concentration of pollen. The severity score during the first period of the pollen season was significantly correlated with both the early and the late asthmatic responses to the allergen observed before the season (r2 = 0.50; P < 0.005). Bronchial sensitivity to methacholine was significantly increased both after allergen challenge and after seasonal exposure, but these increases correlated neither with each other nor with the severity score. We conclude that bronchial responses to experimental exposure to allergens, but not the changes in nonspecific airway responsiveness, can, in part, predict the severity of asthma exacerbation during the pollen season.

Adolescent↗
PubMed2006

Changes in airway inflammation following nasal allergic challenge in patients with seasonal rhinitis.

BACKGROUND: Seasonal allergic rhinitis could predispose to the development of chronic bronchial inflammation as observed in asthma. However, direct links between nasal inflammation, bronchial inflammation and airway responsiveness in patients with seasonal allergic rhinitis and without asthma are not fully understood. The aim of this study was to analyse the changes induced by allergic nasal challenge outside the pollen season in airway responsiveness and bronchial inflammation of patients with seasonal allergic rhinitis. METHODS: Nine patients were evaluated after either grass pollens or placebo nasal challenge in a randomized cross-over double-blinded trial. Nasal parameters were recorded hourly and airway responsiveness was assessed by methacholine challenge. Cytological examinations and cytokine measurements were performed in nasal lavage and induced sputum. Eosinophil activation was investigated by eosinophil-cationic protein expression and secretion. RESULTS: Airway responsiveness was increased after allergic nasal challenge. Total eosinophils and eosinophils expressing eosinophil-cationic protein were increased in induced sputum after allergic nasal challenge. Both eosinophil number and eosinophil-cationic protein concentration in induced sputum were correlated to methacholine responsiveness. CONCLUSIONS: These results suggest that eosinophils participate to the bronchial inflammation in patients with seasonal allergic rhinitis following allergic nasal challenge outside the pollen season and might explain changes in airway responsiveness.

Adult↗
PubMed1998

Effect of the season on the neurological outcome in children with cardiac arrest.

Twenty children who were successfully resuscitated after cardiac arrest (CA) were retrospectively studied to examine the hypothesis that children with CA may have a worse neurological outcome in hot weather than in cold weather. Of 7 children with CA in the cold season (atmospheric temperature < 14 degrees C), 4 in the warm season (14-24 degrees C) and 9 in the hot season (> 24 degrees C), 5 (71%), 2 (50%), and 1 (11%), respectively, recovered consciousness (P < 0.05). Postresuscitative hyperthermia tended to be frequently observed in the group of children who suffered CA in the hot season, and it appeared to be associated with neurological damage. This preliminary study suggests that the neurological outcome of children with CA changes with the seasons, with a worse neurological outcome for CA in hot weather than in cold weather. A prospective study is required to determine whether, in a hot season or area, cooling of pediatric cardiac arrest victims during cardiopulmonary resuscitation on the scene improves the neurological outcome.

Asphyxia↗
PubMed1998

Seasonality of low birthweight in indigenous Australians: an increase in pre-term birth or intrauterine growth retardation?

We have analysed birthweights of 4,508 Aboriginal and Torres Strait Islander livebirths in the Kimberley region of Western Australia from 1981-93. Mean birthweight varied significantly according to month of birth (F(11) = 2.57, p = 0.003) and low birthweight babies were more common during the wet season. A significant increase in the proportion of very low birthweight (VLBW) babies was observed during the wet season compared with the dry season (OR 2.73; 95% CI 2.3-3.67; p < 0.001); whereas babies weighing 1,500-2,499 g were not significantly more common during the wet season (OR 1.06; 95% CI 0.96-1.17; p = ns). The results indicate that adverse environmental conditions may be associated with increased risk of VLBW. Since newborns weighing less than 1500 g are very likely to be pre-term (< 37 weeks' gestation), the findings also suggest that seasonality of birthweight may be due to an increase in pre-term births rather than an increase in intrauterine growth retardation. Further research is required to identify the underlying causes of an increase in VLBW babies during the wet season.

Birth Rate↗
PubMed1995

Spirometry and ventilation-perfusion inequality in patients with mild allergic asthma before and during the pollen season.

Several studies on asthma have shown a low correlation between gas exchange and spirometry, especially after treatment with bronchodilators. The aim of the present study was therefore to examine both spirometry results and gas exchange during a pollen-free period and at the end of the pollen season in patients with mild and well-controlled allergic asthma. Pulmonary gas exchange was studied using a modified form of the multiple inert gas elimination technique. Lung volumes and forced expiratory flows were measured by common spirometry. During the non-pollen season, spirometry and forced expiratory flows were within the reference values in all but one patient, who had decreased indices for airway flow. Three other patients showed signs of minor gas exchange impairment. During the pollen season, FRC was slightly increased (P < 0.05) and MEF50 was slightly decreased (P < 0.05) for the group. Two patients had an increased index for gas exchange impairment (log SDQ was 0.64 and 0.59) and four patients had borderline log SDQ (0.50 to 0.56). However, the mean log SDQ was not increased in the pollen season. The results show that, both in the pollen season and in the pollen-free season, low degrees of gas exchange impairment could be present in pollen allergic asthmatic patients despite normal spirometry. The low degree of gas exchange impairment in some patients indicates the presence of airway inflammation with oedema and/or secretion. However, high degrees of ventilation-perfusion inequality were not observed in these patients where air flow rates were mainly normal.

Adult↗
PubMed1998

Understanding seasonal affective disorder and experiences in northern Norway.

PURPOSE: To better understand a diagnosis corresponding to mental distress and sleep disturbance associated with seasonal change known as seasonal affective disorder (SAD). DESIGN: This ethnographically guided investigation, conducted from 1993 through 1995 in Tromsøo, Norway at a latitude of 69 degrees north describes how the residents experience extreme seasonal change. METHOD: Qualitative interview data from 28 participants plus observation, folk wisdom, and literature were used to describe local understanding of seasonality and illustrate how cultural values, meanings, and practices can contribute to alternative experiences that differ from scientists' expectations. FINDINGS: While there is evidence that human physiologic alterations occur in response to the changing seasonal patterns of light and dark and to a greater extent, at latitudes further from the equator, the findings related to psychological changes and their causes remain inconsistent and controversial. CONCLUSION: Investigators concerned with the effects of seasonal change should be aware of and develop an appreciation of cultural perception and adaptation.

Adaptation, Psychological↗
PubMed1984

Seasonal changes in glycogen level and size of pinealocytes of the white-footed mouse, Peromyscus leucopus: a semiquantitative histochemical study.

Glycogen level in and size of pinealocytes of the feral, white-footed mouse Peromyscus leucopus, were studied by a semiquantitative histochemical method to determine whether seasonal changes exist in them under natural conditions, what temporal pattern they exhibit, and whether 24-hour changes in these parameters exist in different seasons, as shown in the laboratory dd-mice. Marked seasonal changes were seen in both glycogen levels and nuclear densities (ANOVA p less than 0.005). The size of pinealocytes at 09:00 to 10:00 showed one peak (and nadir) seasonal change, with the smallest size in winter (December and February) and a larger size in warmer seasons, with the maximum value in July. Glycogen level in pinealocytes at 09:00 to 10:00 showed bimodal seasonal changes, with lower levels in fall and spring and higher levels in winter and summer. In fall, a circadian trend in glycogen level in pinealocytes was seen, with a higher level at the end of the light period. In winter, the glycogen levels were very high at 09:00, 13:00, 17:00, and 21:00 examined and showed dampening of time-of-day differences. On the other hand, the size of pinealocytes followed a time-of-day change (P less than 0.005), being largest at 13:00 and smallest at 21:00. Thus, marked changes in quantitative structure and chemical activities, suggesting changes in functional activity, in pinealocytes were noted especially in severe, cold winter.

Acclimatization↗
PubMed1995

The influence of season, photoperiod, and pineal melatonin on immune function.

In addition to the well-documented seasonal cycles of mating and birth, there are also significant seasonal cycles of illness and death among many animal populations. Challenging winter conditions (i.e., low ambient temperature and decreased food availability) can directly induce death via hypothermia, starvation, or shock. Coping with these challenges can also indirectly increase morbidity and mortality by increasing glucocorticoid secretion, which can compromise immune function. Many environmental challenges are recurrent and thus predictable; animals could enhance survival, and presumably increase fitness, if they could anticipate immunologically challenging conditions in order to cope with these seasonal threats to health. The annual cycle of changing photoperiod provides an accurate indicator of time of year and thus allows immunological adjustments prior to the deterioration of conditions. Pineal melatonin codes day length information. Short day lengths enhance several aspects of immune function in laboratory studies, and melatonin appears to mediate many of the enhanced immunological effects of photoperiod. Generally, field studies report compromised immune function during the short days of autumn and winter. The conflict between laboratory and field data is addressed with a multifactor approach. The evidence for seasonal fluctuations in lymphatic tissue size and structure, as well as immune function and disease processes, is reviewed. The role of pineal melatonin and the hormones regulated by melatonin is discussed from an evolutionary and adaptive functional perspective. Finally, the clinically significance of seasonal fluctuations in immune function is presented. Taken together, it appears that seasonal fluctuations in immune parameters, mediated by melatonin, could have profound effects on the etiology and progression of diseases in humans and nonhuman animals. An adaptive functional perspective is critical to gain insights into the interaction among melatonin, immune function, and disease processes.

Androgens↗
PubMed2005

Regional and seasonal variations in facial sebum secretions: a proposal for the definition of combination skin type.

BACKGROUND/AIMS: Facial sebum secretions are known to change under various circumstances. Facial skin types have been categorized as oily, normal, dry, and combination types. However, these have been evaluated subjectively by individuals to date, and no objective accepted standard measurement method exists. The combination skin type is most common, but its definition is vaguer than the definitions of the other skin types. METHODS: We measured facial sebum secretions with Sebumeter. Sebum secretions were measured at five sites of the face seasonally for a year, in the same volunteers. Using the data obtained we developed a set of rules to define the combination skin type. RESULTS: Regional differences in sebum secretion were confirmed. Sebum secretions on forehead, nose, and chin were higher than on both cheeks. Summer was found to be the highest sebum-secreting season, and seasonal variations were found in the T- and U-zones. A mismatch of skin type in the T- and U-zones in more than two seasons appears to be close to subjective ratings of what is described as the 'combination' skin type. CONCLUSION: We showed that the face shows definitive regional and seasonal variations in sebum secretion. To define the combination skin type, seasonal variations in sebum secretion should be considered in addition to regional variations.

Face↗
PubMed1994

Seasonality in lower leg length velocity in prepubertal children.

Despite low measuring error, annual growth is poorly predicted by short-term measurements of the lower leg. In order to study if this low correlation can be explained by seasonal changes in lower leg length (LLL) velocity, we followed short-term growth longitudinally in 50 prepubertal children with normal height and growth velocities. Height measurements were performed at 4-week intervals and LLL measurements at 1-2 week intervals. Analysis of annual growth showed seasonality in the monthly mean height velocity values: 5.06 (SD 5.02) cm/year during the autumn and 8.15 (SD 5.22) cm/year in the spring. Similarly, the monthly mean LLL velocity values changed from 1.80 (SD 1.07) cm/year in the autumn to 2.63 (SD 0.92) cm/year in the spring. The correlation between monthly LLL and annual height velocity was low (r = 0.27). The technical error of the LLL measurement was 7-8% of the mean monthly LLL velocity, while the mean values changed by 31% over the seasons. The annual height velocity was virtually independent of the variation in growth rate over the seasons. It is concluded that there is significant seasonality both in height and LLL velocity and that it takes place at the same time for both measures. Seasonality in LLL has not been reported previously and must be considered when studying short-term growth, for example when LLL is used for prediction of annual height velocity or when a short-term treatment effect is examined using LLL.

Anthropometry↗
PubMed2003

Seasonality of growth and the relationship between weight and height gain in children under three years of age in rural Malawi.

AIM: To describe the seasonal pattern of growth and analyse the relationship between weight and height gain in children under 3 y of age. METHODS: A population-based cohort of 767 children was prospectively followed from birth until 36 mo of age in rural Malawi, southeast Africa. Weight and height measurements were collected at monthly intervals until 18 mo of age and quarterly thereafter. Gains in weight and height and prevalence of malnutrition in different seasons were calculated. The relationship between weight and height gain was analysed using a series of correlation analyses. RESULTS: Both weight gain and linear growth velocity showed an age-dependent seasonal pattern. After infancy, periods of maximal or minimal height increments systematically occurred 3 mo after those for weight gain. The prevalence of malnutrition also followed a seasonal pattern, peaking a few months after periods of reduced growth. Despite the overall pattern, weight gain and subsequent linear growth were not correlated on an individual level. At any point, however, a child's weight for height was directly, albeit weakly, correlated to height gain in the subsequent 3-mo interval. CONCLUSION: Growth of children under 3 y of age followed an age-dependent seasonal pattern. The poor correlation between children's weight and height increments suggests that seasonality affected weight gain and linear growth through different mechanisms.

Age Factors↗
PubMed2006

Seasonal variation of the onset of presentations in stage 1 sarcoidosis.

Sarcoidosis is a chronic disease with an unknown aetiology. Our aim was to evaluate the pattern of seasonality of stage 1 sarcoidosis subjects who had symptoms by all cases, by age and by both genders. In this study, we used Roger's test for cyclic variation to prove that this seasonal variation was more than chance. Four hundred ninety-two consecutive patients with sarcoidosis who presented different clinical symptoms were included in this retrospective cohort study. According to the chest X-ray examinations, 185 patients had stage 1, while 307 patients in control group had stage 0, 2, 3 and 4 sarcoidosis. The demographic features, presenting clinical features, course of the disease, initial diagnostic methods and both the month and the age at the initial diagnosis for each patient were analysed on chart reviews. Roger's test for cyclic variation was used to determine the significance of any seasonal variation of incidence. Otherwise, t-test was used. The distribution of cumulative monthly presentations for patients with stage 1 peaked in April (108% above the average) and was lowest in October, November and December (48% below the average) (p < 0.001). Seasonality of the control group peaked in May (84% above the average) and was lowest in August (69% below the average) (p < 0.001). The seasonal pattern of subjects within both groups was influenced by some age groups and by both genders (p < 0.05). Some differences in the amplitude of the seasonal variation by age and by both genders increase the possibility of interactions among age, gender and the disease. Further well-designed and prospective studies are required to better understand the importance of our findings and the pathogenesis of the disease.

Adult↗
PubMed2004

Seasonal variation in fluoride intake: the Iowa fluoride study.

OBJECTIVES: Although patterns of fluid intake change seasonally, little is known about how fluoride intake varies by season. Since even short-term increases in fluoride intake could potentially lead to more dental fluorosis, it is valuable to assess the degree of seasonal variation to determine if it increases fluoride intake to levels that could be considered a concern in young children. METHODS: Questionnaires were mailed periodically to participants in the Iowa Fluoride Study beginning at 6 weeks of age and continuing for a number of years. Parents recorded the date; child's weight; estimates of the amounts of water and other beverages that their child consumed per week; the type and amount of any fluoride supplements used; and the type, amount, and frequency of dentifrice used, with an estimate of the proportion of dentifrice that was swallowed. Documented water fluoride levels from municipal sources and assay of individual sources were linked to water intake amounts. Total fluoride intake per kg body weight was estimated from water, other beverages, fluoride supplements, and ingested dentifrice. Generalized linear models compared temperature-related and seasonal effects after adjusting for the child's age. RESULTS: Separate analyses for ages 0-12 months and 12-72 months showed different results. Children younger than 12 months of age did not exhibit significant seasonal or temperature-related variation in any of the components of fluoride intake. Children aged 12-72 months had higher fluoride intake (mg F/kg bw) from beverages in summer (P<.05), and fluoride intake from beverages increased with monthly temperature (P<.001). CONCLUSIONS: Fluoride intake from beverages for children aged 12-72 months is slightly higher in the summer and increases with mean monthly temperature. Fluoride intake from supplements and dentifrice did not change significantly with either season or temperature.

Age Factors↗