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PubMed1999

Demonstration of bronchial eosinophil activity in seasonal allergic rhinitis by induced plasma exudation combined with induced sputum.

BACKGROUND: Patients with seasonal allergic rhinitis may develop bronchial hyperresponsiveness during the active disease period. Eosinophil activation may occur in the bronchial mucosa and may be reflected by increased sputum levels of eosinophil cationic protein (ECP), especially when ECP binding proteins such as alpha 2-macroglobulin pass through the lamina propria and across the epithelium into the airway lumen. A study was therefore undertaken to determine histamine airway responsiveness (FEV1) and bronchovascular responsiveness (exudation of alpha 2-macroglobulin) to histamine in subjects with seasonal allergic rhinitis, and to explore whether sputum ECP levels are increased by the use of induced exudation followed by induced sputum. METHODS: Eleven patients with seasonal allergic rhinitis were examined before and during a birch pollen season. Sputum was induced by inhalation of 4.5% saline twice before and twice during the pollen season. Histamine inhalations were given before the second of each pair of sputum inductions at increasing concentrations until FEV1 was reduced by 20%. Sputum levels of alpha 2-macroglobulin and ECP were determined as indices of bronchial exudation of plasma and activation of bronchial eosinophils, respectively. RESULTS: Bronchomotor responsiveness increased during the pollen season (median difference in the reduction of FEV1 9% (95% confidence interval (CI) -3 to 26)) but histamine induced exudation of plasma was not increased. Baseline sputum levels of alpha 2-macroglobulin and ECP did not increase. Histamine induced exudation of alpha 2-macroglobulin was associated with increased sputum levels of ECP exclusively during the pollen season (median difference 8.2 ng/ml (95% CI 0.4 to 562.0)). CONCLUSION: Bronchial hyperresponsiveness in seasonal allergic rhinitis may not be associated with bronchovascular exudative hyperresponsiveness. Sputum levels of ECP were increased only during the season, and only after induced exudation (potentially moving ECP to the mucosal surface). It is suggested that the combined method of induced exudation and induced sputum may significantly improve the yield of some markers of inflammation in sputum samples.

Adult↗
PubMed2007

Seasonality of infectious diseases.

Seasonality, a periodic surge in disease incidence corresponding to seasons or other calendar periods, characterizes many infectious diseases of public health importance. The recognition of seasonal patterns in infectious disease occurrence dates back at least as far as the Hippocratic era, but mechanisms underlying seasonality of person-to-person transmitted diseases are not well understood. Improved understanding will enhance understanding of host-pathogen interactions and will improve the accuracy of public health surveillance and forecasting systems. Insight into seasonal disease patterns may be gained through the use of autocorrelation methods or construction of periodograms, while seasonal oscillation of infectious diseases can be easily simulated using simple transmission models. Models demonstrate that small seasonal changes in host or pathogen factors may be sufficient to create large seasonal surges in disease incidence, which may be important particularly in the context of global climate change. Seasonality represents a rich area for future research.

Communicable Diseases↗
PubMed2000

Influence of method on seasonal distribution of attempted suicides in italy.

To verify if attempted suicides follow different seasonal distributions according to the method chosen, we studied the Italian monthly distribution of admissions for attempted suicide in the period 1984-1995 according to gender and age, distinguishing between non-violent (ICD 950-952) and violent (ICD 953-958) attempted suicides. The effect of temperature was also taken into account. A clear asymmetry in seasonal distribution of events can be observed in the oldest age groups in both genders, with a peak in warmer months. Only male attempted suicides by violent methods show a clear asymmetry in seasonal distribution, with a peak in spring months and a trough in autumn months. Spectral analysis, more accurate in detecting seasonal rhythms than analyses that only compare monthly seasonal means, identifies a circannual rhythm for violent suicides in both genders. The seasonal components of total variance in attempted suicides account for 16.5 and 12.4%, respectively, of violent male and female attempted suicides. Among males, a significant (p < 0.05) 4 cycles/year pattern is seen alongside the more relevant (89.4%, p < 0.01) 1 cycle/year distribution. Among females, aside from the 1 cycle/year distribution (63.3%, p < 0.01) noted, a 6 cycles/year pattern is found to contribute significantly (16.9%, p < 0.05) to the seasonal component of variance. A clear relationship with temperature indicators is noted among males: higher temperatures positively correlate with attempted suicides, whereas cooler temperatures seem to exert a protective action. Female attempts show a less evident correlation with indicators of temperature. Sample composition by age and gender and the lack of distinction between methods of attempted suicide may have obscured the seasonal component of some classes of attempted suicide in previous studies. The circannual rhythm found in this study of violent attempted suicide in relation to climate seasonal change confirms the importance of taking chronobiological variables into account in the evaluation of patients at risk of suicide.

Adolescent↗
PubMed2005

Women's access to food-processing technology at the household level is associated with improved diets at the pre-harvest lean season in The Gambia.

BACKGROUND: Women's access to food processing technology at the household level may have positive dietary benefits during the pre-harvest lean season when households are most stressed from food shortages and higher energy expenditures from agricultural work. OBJECTIVE: This study in rural Gambia was conducted to determine if women's access to small manually operated oil presses (ram) for sesame oil extraction had any significant effects on seasonal fluctuations of household oil supply and on dietary intakes of women and children. METHODS: Participants were 40 women and children with access to community-based motorized oil press expellers (Expeller-control), 37 women and children with access to village-based ram presses (Press-experiment), and 43 women and children with access to both ram press and motorized expeller (Combination). Dietary data were collected at baseline, at peak oil-pressing, at pre-harvest lean, and at the post-harvest seasons. RESULTS: Households in the Press-experiment and Combination groups consumed 37 and 51 percent more oil, respectively, than those in the Expeller-control group during the pre-harvest lean season. Women from the Press-experiment and Combination groups consumed more energy at the lean season than those in the Expeller-control group. Similarly, children from the Press-experiment and Combination groups consumed more protein at peak oil-processing season than those from the Expeller-control group. At the pre-harvest season children from these two groups also consumed more protein, however, only the consumption of the Combination children was statistically significant compared with that of the Expeller-control group (p < .05). Press-experiment children consumed more nutrient-dense weaning foods during the pre-harvest lean season than Expeller-control children. CONCLUSIONS: Women's access to appropriate technology can provide the means to "add value" to their agriculture product, which may serve as an economic stabilizer with potential to increase dietary intakes and incomes, especially during the pre-harvest lean season.

Adult↗
PubMed1994

[Analysis of the seasonal variations in mean birth weight and mean gestational period of 47 prefectures in Japan].

Seasonal variations of the mean gestational period (MGP) and mean birth weight (MBW) are examined by the traditional method of time-series analysis during the period from 1979 to 1983 in Japan. The results of the present study support the existence of a seasonal rhythm of MGP. Generally MGP showed a deep trough in winter and a shallow one in summer to early autumn. This pattern was similar to that of MBW. The two time series showed a statistically significant coincidence in their monthly fluctuations, and a statistically significant correlation was also observed for their amplitude. According to these results, we concluded that the seasonality in MGP plays an important role in creating the seasonality in MBW. However, the seasonality in MGP can not be the only definitive factor that totally regulates the seasonal variations in MBW. The relationship between the two time series is considered to be different among different seasons as well as regions. For example, we observed a decrease of the seasonal index in winter in the same month for both MBW and MGP, but not necessarily in summer. This suggests that the etiology of the decrease in seasonal variations is different between summer and winter.

Birth Weight↗
PubMed1986

Seasonal variation in the feedback of sex steroid hormones on serum LH concentrations in the male horse.

The possibility of seasonal variation in the feedback effect of testosterone or oestradiol was investigated by giving replacement treatment to geldings for 2-3 weeks during breeding and non-breeding seasons. In the non-breeding season, testosterone suppressed LH values (mean +/- s.e.m., ng/ml) in all geldings (before treatment, 7.5 +/- 2.3; final treatment week, 1.8 +/- 0.2; P less than 0.05), whereas early in the breeding season, testosterone caused a prolonged rise in LH (before, 6.8 +/- 2.3; final week, 18.9 +/- 6.4; P less than 0.05). In all testosterone experiments, LH returned to pretreatment levels within 2 weeks after treatment. Oestradiol treatment caused a prolonged increase (P less than 0.05) in LH concentrations (mean +/- s.e.m., ng/ml) in both seasons (breeding: before 5.2 +/- 1.1; final week, 16.2 +/- 4.8; non-breeding before, 10.9, 20.1 +/- 5.2). We conclude that in geldings the feedback effect of testosterone varies with season and, further, that testosterone replacement may be able to restore to geldings the stallion's seasonal pattern of LH secretion. The results suggest that, in male horses, testosterone and possibly oestradiol, are important components in the neuroendocrine pathway controlling seasonal breeding and, moreover, are essential for the generation of a positive signal for LH secretion in the breeding season.

Animals↗
PubMed1990

Correlation with changes in horns and pelage, but not reproduction, of seasonal cycles in the secretion of prolactin in rams of wild, feral and domesticated breeds of sheep.

Seasonal cycles were monitored in groups of wild (mouflon), feral (Soay) and domesticated breeds of sheep (Shetland, Blackface, Herdwick, Norfolk, Wiltshire, Portland, Merino, Soay x Portland and Soay x Merino) living outdoors near Edinburgh (56 degrees N). Changes in the blood plasma concentrations of prolactin and FSH, and growth of the horns and pelage were measured every half calendar month from 1 to 3 years of age. In all breeds there was a clearly defined seasonal cycle in the plasma concentration of prolactin with an 18-66-fold increase in mean values from the nadir in November and December to the peak in May and June. The seasonal increase in prolactin was closely correlated with the seasonal increase in the growth of the horns, both within and between breeds (e.g. time of peak prolactin vs horn growth for 11 breeds, R = 0.62, P less than 0.05). In the mouflon, Soay and some of the domesticated breeds of sheep (Wiltshire, Herdwick and Shetland), the seasonal increase in prolactin was also temporally correlated with the resurgence of growth of the pelage in spring and a conspicuous moult. In the other breeds developed to produce fine wool (e.g. Norfolk, Portland and Merino), there was no clear seasonal change in the pelage and growth continued throughout the year. Comparison between breeds indicated that continuous growth of the pelage was associated with higher plasma prolactin concentrations in winter. The times of the seasonal changes in plasma concentrations of prolactin were not significantly correlated with the corresponding changes in the plasma concentrations of FSH. The overall results are consistent with a role for prolactin related to the growth of the horns and pelage rather than the seasonal cycle in reproduction. The differences between the wild-type and the domesticated breeds in the pelage represent the effect of selective breeding to produce a long fine fleece which has involved changes in both the seasonal pattern of prolactin secretion and the growth characteristics of the hair fibres.

Animals↗
PubMed1992

Variation in the timing of the reproductive season among breeds of sheep in relation to differences in photoperiodic synchronization of an endogenous rhythm.

Photoperiod may regulate seasonal reproduction either by providing the primary driving force for the reproductive transitions or by synchronizing an endogenous reproductive rhythm. This study evaluated whether breed differences in timing of the reproductive seasons of Finnish Landrace (Finn) and Galway ewes are due to differences in photoperiodic drive of the reproductive transitions or to differences in photoperiodic synchronization of the endogenous rhythm of reproductive activity. The importance of decreasing photoperiod after the summer solstice in determining the onset and duration of the breeding season was tested by housing ewes from the summer solstice in either a simulated natural photoperiod or a fixed summer-solstice photoperiod (18 h light:6 h dark; summer-solstice hold). Onset of the breeding season within each breed did not differ between these photoperiodic treatments, but Galway ewes began and ended their breeding season earlier than Finn ewes. The duration of the breeding season was shorter in Galway ewes on summer-solstice hold than on simulated natural photoperiod; duration did not differ between photoperiodic treatments in Finn ewes. The requirement for increasing photoperiod after the winter solstice for initiation of anoestrus was tested by exposing ewes from the winter solstice to either a simulated natural photoperiod or a winter-solstice hold photoperiod (8.5 h light:15.5 h dark). Onset of anoestrus within each breed did not differ between these photoperiodic treatments, but the time of this transition differed between breeds. These observations suggest that genetic differences in timing of the breeding season in Galway and Finn ewes do not reflect differences in the extent to which photoperiod drives the reproductive transitions, because neither breed requires shortening days to enter the breeding season or lengthening days to end it at appropriate times. These findings are consistent with the hypothesis that photoperiod synchronizes an endogenous rhythm of reproductive activity in both breeds and that genetic differences in timing of the breeding season reflect differences in photoperiodic synchronization of this rhythm.

Anestrus↗
PubMed2002

In-season changes in resistance to insecticides in Helicoverpa armigera (Lepidoptera: Noctuidae) in India.

Discriminating doses of fenvalerate, cypermethrin, quinalphos, and endosulfan were determined with an insecticide-susceptible Helicoverpa armigera (Hübner) strain. In-season changes in insecticide resistance were monitored with discriminating dose assays at weekly intervals throughout the cropping season for 6 yr from 1993 to 1999 in central India. Resistance to pyrethroids was high throughout all seasons. Resistance to 0.75 microg of quinalphos was consistent, with seasonal averages ranging from 23 to 27% survival over the 6 yr. Resistance to 10.0 microg of endosulfan was moderately high at an average of 40-47% survival during 1993-1994 and in 1997-1998. It was lower in 1996-1997 at 27%, and in 1998-1999 at 33%. The weekly monitoring data for all seasons were pooled and the consolidated 6-yr seasonal average profile indicated that resistance to quinalphos and endosulfan was low during September at 21 and 27% survival, respectively, but increased to 28 and 37% by the end of November. Resistance levels to organophosphates and endosulfan increased during the season, depending on the use of these compounds. At almost all monitoring sites, the within-season changes in quinalphos resistance for all seasons through the study period followed a trend similar to that of endosulfan. The results suggest the possibility of cross-resistance between these compounds. Based on this study and the existing information on cotton pest management, we have developed a "window strategy" for cotton pest management with specific emphasis on the management of insecticides for effective control of H. armigera. This strategy has contributed to improved control at reduced costs in extensive trials.

Animals↗
PubMed1994

Seasonal variations in the ultrastructure and production of androgen-dependent proteins in the seminal vesicles of a Saharian rodent (Psammomys obesus).

The effects of seasonal variations and experimental deprivation and substitution of androgen in the seminal vesicles of the Saharian rodent Psammomys obesus were investigated. Cytological studies showed that, during the breeding season, epithelial cells had large amounts of rough endoplasmic reticulum (RER) and substantial apocrine secretion. During the non-breeding season, RER cisternae were no longer expanded and apocrine secretion was rare. Castration during the breeding season was followed by regression of the RER and the disappearance of apocrine secretion. Treating castrated animals and animals in the non-breeding season with testosterone for 15 days caused reactivation. Eight major proteins with molecular weights of 120, 78, 67, 41, 37, 34, 21 and 14.4 kDa were present in homogenates during the breeding season; six (92, 41, 36, 35, 21 and 14.4 kDa) were found in seminal vesicle secretions. During the non-breeding season, the very large amounts of the 21 kDa protein were greatly reduced; conversely the 45 kDa protein increased. Electrophoretic patterns of homogenates from animals castrated during the breeding season showed eight proteins differentially induced (37, 34, 21 and 18 kDa) or repressed (67, 45, 38 and 35 kDa) by testosterone, of which the 21 kDa protein decreased most dramatically after castration. The effects of castration were reversed by the administration of testosterone. During the non-breeding season, the synthesis of the four induced proteins was stimulated by testosterone treatment; conversely that of the 45 kDa protein was suppressed.

Animals↗
PubMed2006

Seasonal changes in sperm chromatin condensation in ram (Ovis aries), Iberian red deer (Cervus elaphus hispanicus), and brown bear (Ursus arctos).

The effect of seasonality (temperate environment, Spain) on the chromatin status of ovine (Churra breed), Iberian red deer, and brown bear spermatozoa was studied. This work aims to improve genetic resource banks (GRBs) by enhancing existing knowledge of the effect of season on sperm quality. Samples were obtained by electroejaculation in Iberian red deer and brown bear and by artificial vagina in ram. We used the sperm chromatin structure assay (SCSA) to study the level of chromatin condensation of the spermatozoa in each studied period. These periods were: ram, breeding season (from September to January), nonbreeding season (from February to June), and summer (July and August); red deer, breeding season (September and October), postbreeding (November and December), and nonbreeding (the rest of the year); brown bear, prebreeding (March and April), breeding (May and June), postbreeding (July and August), and nonbreeding (September to February). Chromatin in ram was more decondensated in summer, and no differences were observed between the breeding and nonbreeding season. However, in red deer, spermatozoa obtained during the nonbreeding season showed more condensed chromatin than those obtained in the rut and postrut periods. Similarly, brown bear rendered sperm with loose chromatin in the prebreeding and breeding seasons. Less condensed chromatin in the breeding season may be related to faster epididymal transit due to enhanced spermatogenesis.

Animals↗
PubMed2004

Evaluation of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds of sheep: II. Reproduction of F1 ewes in fall mating seasons.

Objectives were to estimate effects of sire breed (Dorset, Finnsheep, Romanov, Texel, and Montadale), dam breed (Composite III and northwestern whiteface), mating season (August, October, and December), ewe age (1, 2, and 3 yr), and their interactions on reproductive traits of F1 ewes. A total of 1,799 F1 ewes produced 3,849 litters from 4,804 exposures to Suffolk rams during 35-d mating seasons over 3 yr. Ewes were weighed at breeding. Conception rate and ewe longevity (present or absent at 42 mo of age) were determined. Number born and litter birth weight were recorded, and number and weight at weaning and 20 wk of age were analyzed separately for dam- and nursery-reared litter mates. Total productivity through 3 yr of age for each ewe entering the breeding flock was calculated as the sum of 20-wk weights for dam- or nursery-reared lambs. Interactions of sire breed x mating season, sire breed x ewe age, and mating season x ewe age were generally significant, whereas interactions of sire breed, mating season, and ewe age x dam breed were seldom detected. Interactions of sire breed x mating season were often due to changes in rank as well as magnitude, indicating the importance of matching sire breed to a specific mating season. The number born to Dorset-, Texel-, and Montadale-sired ewes was not affected by dam breed; however, Finnsheep-sired ewes out of northwestern whiteface dams were more prolific than Finnsheep-sired ewes out of Composite III dams, and the opposite situation existed for Romanov-sired ewes. Least squares means of sire breeds (P < 0.001) for total productivity of dam-reared lambs were 98.5, 103.5, 106.9, 124.6, and 154.9 kg/ewe entering the breeding flock for Texel, Dorset, Montadale, Finnsheep, and Romanov, respectively. Superior reproduction of Romanov-sired ewes was due to greater conception rate and prolificacy for each mating season and ewe age, as well as greater ewe longevity. Total productivity of F1 ewes by Composite III dams (125.6 kg) was greater (P < 0.001) than for ewes born to northwestern whiteface dams (109.7 kg), and the effect of mating season increased (P < 0.001) from August to October to December. Litter weight at 20 wk of age of 2- and 3-yr-old ewes was similar but greater (P < 0.001) than for 1-yr-old ewes. Experimental results provide comprehensive information about the appropriate use of these breeds in crossbreeding systems to meet specific production-marketing objectives.

Age Factors↗
PubMed2006

An evaluation of the seasonality of veterinary treatments for lameness in UK dairy cattle.

Of the 4 main diseases causing lameness in UK dairy cattle, 2 (digital dermatitis and foul-in-the-foot, or interdigital necrobacillosis) are infectious diseases that are commonly associated with similar underfoot conditions, and 2 (sole ulcer and white-line disease) result from subclinical laminitis. Comparison of the seasonality of these 2 diseases can identify whether their own unique risk factors are more important than the risk factors they share. Using a database from 46 veterinarians distributed across the United Kingdom, the seasonality of treatments for these 4 diseases was evaluated. This analysis showed that the seasonality of lameness in UK dairy cattle was significantly reduced in comparison with previous reports from the 1980s. This was primarily due to 1) a reduction in the seasonality of digital dermatitis (outbreaks of which accounted for 6.7% of veterinary reports), with only 60% of reports during the winter as opposed to 72% in earlier studies, and 2) a change in the seasonality of white-line disease from a disease that was most commonly seen in the winter (55% of reports) to a disease that was most commonly reported in the late summer or early autumn, with significantly more reports in August and October than in February. Comparison of the seasonality of digital dermatitis and foul-in-the-foot showed a significant difference in the seasonality of the 2 diseases, with foul-in-the-foot being significantly more common compared with digital dermatitis in June and August. This implies that significant risk factors exist for digital dermatitis that are not as important for foul-in-the-foot. The difference in the seasonality of sole ulcer and white-line disease was even more marked, with white-line disease being significantly more common than sole ulcer from August to October, despite these diseases being more closely linked in the literature than digital dermatitis and foul-in-the-foot. This comparison shows that the seasonality of lameness has changed in the United Kingdom and that white-line disease has significantly different risk factors than sole ulcer.

Animals↗
PubMed2002

Seasonal variation in the incidence of aneurysmal subarachnoid hemorrhage in hospital- and community-based studies.

OBJECT: The aim of this study was to examine seasonal variations in the onset of aneurysmal subarachnoid hemorrhage (SAH) in one hospital-based and one community-based patient series. METHODS: The study population consisted of 941 patients with aneurysmal SAH who were admitted to Shimane Prefectural Central Hospital and 358 patients who were treated in Izumo City, Japan. When investigated as a whole, no significant seasonal variations were found in either population; however, in both series, statistically significant seasonal trends, with a peak in winter and a nadir in summer, were found among patients aged 59 years or younger (p < 0.05 for the hospital-based series and p < 0.005 for the community-based series), but not among those aged 60 years or older, regardless of sex. In the hospital-based series, seasonal variations were most apparent at certain times of day, with significant variations observed between 8:00 a.m. and 10:00 a.m. or 8:00 a.m. and noon (p < 0.001 and p < 0.005, respectively), regardless of patient age, and between 4:00 p.m. and 6:00 p.m. for patients aged 59 years or younger (p < 0.05). Consequently, seasonal variations were significant during daytime hours (between 8:00 a.m. and 8:00 p.m., p < 0.005) but not during the night (between 8:00 p.m. and 8:00 a.m.). Similar tendencies were found in the community-based series. Among patients aged 59 years or younger who had no risk factors for SAH, these seasonal variations were significant in both series. In patients with untreated hypertension, who were current smokers and daily alcohol drinkers, however, no significant patterns were observed in either series, even among younger patients. CONCLUSIONS: In both hospital- and community-based studies, aneurysmal SAH appears to undergo seasonal variation, with a peak in winter and a nadir in summer. This seasonal pattern may be derived mainly from the occurrence of SAH in the morning, but may also be modified by patient age and SAH risk factors, resulting in the masking of significant seasonal patterns when all patients are considered together.

Adult↗
PubMed1985

Serum proteins of three turkey strains under different seasonal conditions.

Total serum protein and serum protein fractions of three local turkey strains (White, Red, and Black) were measured under different seasonal conditions. Total serum protein was influenced (P less than .05) by strain (6.00, 6.15, and 6.28 g/100 ml for White, Red, and Black, respectively) and sex (6.02 and 6.26 g/100 ml for males and females, respectively). Highest levels were recorded under moderate seasonal conditions and lowest under high temperature and low humidity. The interactions of strain X sex and sex X season were not significant (P greater than .05), whereas strain X season was significant (P less than .05). Highest levels of albumin were encountered in Black and Red strains. Sex and season did not exert significant effects (P greater than .05); only the interaction of strain X season was significant (P less than .05). Strain had a significant effect on alpha-1 but not on alpha-2, beta-, and gamma-globulins, whereas sex was a source of variation in all globulins (P less than .05). Season induced significant (P less than .05) variation in globulins. Maximal levels were observed under moderate temperature and relative humidity. Strain X season and strain X sex interactions were not significant with regard to alpha-1 values. Similar trends were observed in beta-globulins for strain X sex and season X sex interactions (P greater than .05).

Animals↗
PubMed1998

Immunoepidemiology of Dracunculus medinensis infections II. Variation in antibody responses in relation to transmission season and patency.

The serum antibody responses (specific IgG1, IgG4, and IgE, and total IgE) to Dracunculus medinensis infection in humans from a highly endemic area of northern Ghana were examined regularly by ELISA over a period of one year in cohorts of individuals who developed a patent D. medinensis infection during the study period (actively infected category), or who claimed to have never had a patent infection (endemic normal category). The results were analyzed in relation to seasonality and time of patency of infection. For individuals in the actively infected category, a clear seasonal variation in the mean levels of specific IgG1 and IgG4 was found, with the highest levels late in the dry season and early in the rainy season, when transmission is high, and the lowest levels late in the rainy season and early in the dry season. Endemic normal individuals responded with low and fluctuating levels of specific IgG1 and with low and nonfluctuating levels of specific IgG4. For specific and total IgE, no seasonal variation was observed in any of the two infection status categories. In relation to time of patency of infection (only involving the category of actively infected individuals), the mean levels of specific IgG1 and IgG4 increased from two months before patency of infection, peaked during patency, and then gradually decreased for four months until a constant level was reached. No significant fluctuations in the levels of specific and total IgE were observed in relation to time of patency. The present study thus showed extensive variation in levels of D. medinensis-specific IgG1 and IgG4 (but not IgE) over time. Seasonal variations in antibody responses may also occur in other helminth infections, especially those with seasonal transmission, and these should be taken into consideration when interpreting the results of immunologic studies.

Adult↗
PubMed2003

Is there any seasonal influence in spontaneous bleeding of intracranial aneurysm and and/or AVM in Istanbul?

PRINCIPLES: Despite many reports investigating the relationship of subarachnoid haemorrhage and seasonal variation in different parts of the world, there is no clear correlation. As far as we know this subject has not been reported from Istanbul yet. The purpose of this study is to determine if there is any correlation between season and spontaneous subarachnoid haemorrhage (SAH) caused by intracranial aneurysms and/or arteriovenous malformations (AVM) in Istanbul. METHODS: Data were collected retrospectively from the medical reports of patients having intracranial haemorrhage due to aneurysm and/or arteriovenous malformation. The data were analysed with univariate and chi-square tests for all haemorrhages, for haemorrhages of aneurysms and arteriovenous malformations separately per month and per season respectively for all the patients together and according to gender separately. The ANOVA test was used for testing the monthly distribution of SAH cases with regard to age. RESULTS: There were 761 cases (417 female, 344 male) of intracranial haemorrhage cases (683 intracranial aneurysms, 78 arteriovenous malformations) from 1994-2000. In this study, a seasonal peak in winter and a nadir in autumn for all subarachnoid haemorrhages were observed but the findings were not significant statistically. The peak season was winter for bleeding due to both aneurysms and AVM's. While the nadir season for aneurysmal bleeding was autumn and was summer for the AVM's. CONCLUSIONS: We did not find any significant statistical relation between seasonal variation and intracranial haemorrhage in the Istanbul province. But the peak of bleeding in winter and the nadir in autumn were noticeable for all intracranial haemorrhages. In Istanbul, beside the individual risk factors such as hypertension, alcohol consumption, lifestyle, and environmental factors like weather, season and other possible factors of which we are not yet aware, the relative increase of population in winter season due to social reasons may have a small contribution to these findings.

Adolescent↗
PubMed1999

Safer sex at holiday centres: providing contraceptive services to seasonal workers.

Many seasonal workers experience an increase in sexual activity whilst employed at a holiday centre. Evidence of sexual risk-taking while at a holiday centre has important social and health implications for purchasers and providers of sexual health services in areas which experience an annual influx of seasonal workers. This research investigates the contraceptive behaviour of seasonal workers and focuses on their access to contraception and sexual health services. In-depth interviews were conducted with seasonal workers at holiday centres along the south coast of England. Respondents were, interviewed at the beginning of the season and again, five months later at the end of the season. This longitudinal methodology enabled changes in contraceptive behaviour to be identified as well as the strategies for seeking contraception and sexual health services throughout the season. The results of this study show that there are a range of different motivations which influence seasonal worker' use of contraception and sexual risk-taking while at a holiday centre. Categories of contraceptive protection are developed to assist purchasers and providers to identify the variety of sexual health needs of workers at holiday centres and determine the most effective strategies for delivering contraceptive and sexual health services to these workers. The paper describes the motivations which influence contraceptive use and sexual risk-taking amongst seasonal workers, identifies the contraceptive and sexual health needs of these workers, and discusses the difficulties workers experienced in meeting these needs while at a holiday centre.

Adolescent↗