Cardiac metabolism. IV. Seasonal variation; seasonal variation in metabolism and drug sensitivity of the isolated toad heart (Bufo marinus).
Explore the source record for details and available documents.
Animals↗
SEARCH · Search PubMed
Results for “Seasonal Variation”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Inter-individual variation, seasonal variation and close correlation of OGG1 and ERCC1 mRNA levels in full blood from healthy volunteers.
The mRNA levels of the nucleotide excision DNA repair gene ERCC1 and the base excision DNA repair gene OGG1 were quantified in 43 healthy volunteers in a dietary intervention trial as markers for the DNA repair capacity. Nine samples were collected from each subject over a period of 52 days. Sampling took place from January to May. The mRNA levels of OGG1 and ERCC1 correlated closely (r = 0.86, P << 0.0001) after normalization to either 18S ribosomal RNA or to beta-actin mRNA. The levels of OGG1 and ERCC1 mRNA were relatively constant within an individual with intra-individual correlation (R(2) = 0.45-0.46) in a General Linear Model. The amounts of ERCC1 and OGG1 relative to 18S RNA were doubled in May compared with January. This coincided with an increase in the monthly influx of sunlight from 18 MJ/m(2) in January to 242 MJ/m(2) in May. The mRNA levels of both ERCC1 and OGG1 were positively correlated to the average daily influx of sunlight in the previous 30 and 5 days (r = 0.49; r = 0.37, respectively, P << 0.001). There were no significant effects of the dietary interventions. The inter-individual variation was 5-10-fold, which is more than the observed 2-3-fold seasonal variation. Thus, despite seasonal variation of the individual mRNA levels, the inter-person variation is still far larger than the intra-person variation, supporting the use as biomarkers.
Adult↗
Rhegmatogenous retinal detachment and seasonal variations.
Seasonal variations of rhegmatogenous retinal detachment (RRD) have been reported in only several studies, mostly from Central and northern Europe. In this study, seasonal incidence of RRD was determined and compared with sunlight exposure per season in the Mediterranean region of south Europe. The study was based on a retrospective review of medical records on 280 eyes of 272 consecutive hospital patients in the district of Split, Croatia, who were treated for primary nontraumatic phakic RRD over a 12-year period (1988-1999). The number of eyes with RRD recorded per season was 79 in summer, 71 in winter, 67 in spring and 63 in autumn. The average number of sunshine hours in Split was 1001 in summer, 698 in spring, 576 in autumn and 457 in winter. No seasonal variations in the occurrence of RRD and no correlation with the mean duration of sunlight exposure per season were found.
Croatia↗
Cerebrospinal fluid variables among alcoholics lack seasonal variation.
Seasonal influences on indices of serotonergic function, including cerebrospinal fluid (CSF) concentrations of the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA), have been reported in psychiatric patients and healthy volunteers. We examined seasonal differences in CSF concentrations of 5-HIAA among 135 alcoholics admitted to a research ward who had a lumbar puncture. No significant seasonal differences were found for either CSF concentrations of 5-HIAA or CSF concentrations of other monoamine metabolites or peptides. The possible explanations for these negative findings are discussed.
Adult↗
Seasonal variation in admissions of psychiatric patients and its relation to seasonal variation in their births.
Inpatient admissions to all psychiatric hospital beds in England and Wales in 1970-73 were studied by month of admission for eight diagnostic groups. The admission rates for schizophrenia showed a pronounced seasonal variation, with a maximum in summer. The seasonal pattern for schizophrenia was very similar to the one shown for mania, although somewhat less marked. The admission rates for neurosis and for the large group of 'all other non-psychotic mental illness' showed little evidence of seasonal variation as there was could largely be explained by social factors. In schizophrenic and manic patients, the pattern of seasonal admissions (peak months July and August) is similar to the pattern reported for their births (peak months February and March). This is consistent with the hypothesis of an abnormal seasonal pattern of parental conception as the cause of the abnormal birth pattern.
Bipolar Disorder↗
Seasonal variation in household, occupational, and leisure time physical activity: longitudinal analyses from the seasonal variation of blood cholesterol study.
The authors examined seasonal variation in physical activity in longitudinal analyses of 580 healthy adults from Worcester, Massachusetts (the Seasonal Variation of Blood Cholesterol Study, 1994-1998). Three 24-hour physical activity recalls administered five times during 12 months of follow-up were used to estimate household, occupational, leisure time, and total physical activity levels in metabolic equivalent (MET)-hours/day. Trigonometric models were used to estimate the peak-to-trough amplitude and phase of the peaks in activity during the year. Total activity increased by 1.4 MET-hours/day (121 kcal/day) in men and 1.0 MET-hours/day (70 kcal/day) in women during the summer in comparison with winter. Moderate intensity nonoccupational activity increased by 2.0-2.4 MET-hours/day in the summer. During the summer, objectively measured mean physical activity increased by 51 minutes/day (95% confidence interval: 20, 82) in men and by 16 minutes/day (95% confidence interval: -12, 45) in women. The authors observed complex patterns of seasonal change that varied in amplitude and phase by type and intensity of activity and by subject characteristics (i.e., age, obesity, and exercise). These findings have important implications for clinical research studies examining the health effects of physical activity and for health promotion efforts designed to increase population levels of physical activity.
Adult↗
Seasonal variations of pigmented naevi. Intercorrelations of clinical and histological variables with special reference to seasonal variation.
During 1984, junctional and compound naevi were registered significantly more often during the summer half-year (May-October) than the total number of naevi, which showed no seasonal variation. A series of 342 of these junctional and compound naevi have been the subject of a blind histological classification. Clinical information was obtained by a questionnaire mailed to the patients. The intercorrelations of 19 histological and 10 clinical variables were studied by chi 2-test. The seasonal variation of these variables was further studied by chi 2-test and by Hewitt's test. Patient's hair colour, eye colour and sex as well as mitoses and localization showed a significant correlation to season of the year. The trends of these findings, compared with the information about tumour duration, indicate a short-term latency effect of UV light on naevi which are excised during the summer half-year.
Adolescent↗
Haematocrit: within-subject and seasonal variation.
This review was undertaken, concerning within-subject biological variation and seasonal variation of haematocrit in normal healthy adults and athletes, to find the limits for natural, intra-individual variation in haematocrit values. The terminology and calculations followed well defined theories, from the field of laboratory medicine, about biological variation. Based on results from 12 studies of 638 normal healthy adults, and which used a sampling interval of 1 day to 1-2 months, the coefficient of within-subject biological variation of haematocrit is 3%. The normal within-subject biological variation (3%) and analytical variation (3%) may explain a relative change of approximately 12% (95% level) [e.g. a change from 0.42-0.47] between two successive haematocrit values, measured with a time interval between 1 day and 1-2 months, in a normal healthy adult. Partly due to haemodilution in warm weather, haematocrit often has a seasonal variation in normal healthy adults; based on results from 18 studies of 24 793 participants, the population mean is approximately 3% lower in summer than winter. Population mean values that are 7% lower in summer than winter have been found in some studies, although no seasonal effect may also be seen, especially in temperate climates. If haematocrit values are sampled at yearly peak and trough time points, with intervals of up to 6 months, a 15% relative change (95% level) can be seen in a normal healthy adult; e.g. a change from 0.42-0.48. Published values for haematocrit in athletes are scarce. It is known that the haematocrit value is influenced by training, especially in the first weeks before a new steady-state is reached. Theoretically, the biological variation in athletes could therefore be greater than in normal individuals. Based on two references addressing the biological variation of haematocrit in athletes, however, the above results are also valid for athletes. Further studies, both in the short term and throughout the seasons, are recommended about the natural variation of haematocrit in athletes.
Adult↗
[Rhegmatogenous retinal detachments. Seasonal variation and incidence].
UNLABELLED: Seasonal variations in the relative incidence of rhegmatogenous retinal detachment were reported as a trend in several studies on the database of relatively limited cohort sizes. PATIENTS AND METHODS: An analysis on this topic was performed with a long-term database. A total of 3073 files of patients with rhegmatogenous retinal detachment, covering 11 years of observation, were reviewed for this study. Patients with signs of long-standing detachment or other predisposing diseases were excluded, so that a basic study population of 2314 patients remained for the analysis. RESULTS: The averaged seasonal incidence of rhegmatogenous detachments revealed a significant (P < 0.005) mid-summer peak (n in July = 228) and a winter trough (mean of December-January = 161; difference = 36%). Phase and curve fitting of the seasonal variations in the number of retina detachment cases was similar to the seasonal variation of the astronomic duration of the day (P < 0.001). The relation was closer compared to the average duration of light exposure per day calculated from behavioural data and the astronomic length of light phase (P < 0.0002). CONCLUSION: This long-time study revealed a close correlation of the relative seasonal incidence of retinal detachment and the seasonal variation of light hours per day. So far, this observations cannot be explained pathogenetically. Two basic hypotheses ought to be investigated further: (1) The influence of light on the generation of toxic oxygen radicals and the subsequent destruction of the vitreous and (2) possible light-induced changes in vitreoretinal adhesion.
Adult↗
[Seasonal variations of lactic fermentation of milk. III. Selection of Str. lactis culture with low degree of sensitivity to seasonal variations of milk composition].
Explore the source record for details and available documents.
Animals↗
Seasonal variation of serum bone GLA protein.
The seasonal variation of serum Bone Gla Protein (BGP) was investigated in 15 normal young individuals (seven women and eight men, aged 27-39 years). Serum BGP exhibited a significant seasonal variation of 23% around the yearly mean (p less than 0.001) with zenith in February and nadir in July. Significant seasonal variations were noted also for serum alkaline phosphatase (p less than 0.01) and serum phosphate (p less than 0.01). Serum calcium, bone mineral content (BMC) and creatinine clearance revealed no significant seasonal variation. The seasonal variation of BGP did not follow the variation in serum total alkaline phosphatase. The seasonal variation of BGP has to be taken into account when using the protein as a marker of bone remodelling activity. The variation was probably caused by changes in the production rate of the protein, since the renal excretion of the protein, as reflected in creatinine clearance, remained unchanged throughout the year.
Adult↗
Trends and seasonal variations in the occurrence of Salmonella in pigs, pork and humans in Denmark, 1995-2000.
A mandatory programme monitoring the occurrence of Salmonella in pork at slaughterhouses and a serological monitoring of slaughter-pig herds has been implemented in Denmark since 1993 and 1995, respectively. All results are stored in a central database. From this, aggregated weekly results of serological and bacteriological samples collected in the period between January 1995 and July 2000 were extracted. In addition, the reported weekly incidence of human infections with S. Typhimurium covering the same time period was obtained. The times series were analysed for trends and cyclic variations by seasonal decomposition. The association between the incidence in humans and the prevalence of Salmonella in pigs and pork, and prevailing weather conditions, were analysed by using a general linear (glm) and a general additive model (gam). Explanatory variables were lagged to account for time elapsed between sampling, consumption, incubation period and case registration. The results of the seasonal decomposition showed an overall declining trend in all three time series. All time series exhibited a double peaked annual cycle. The seasonal variation of the prevalence in pork and the human incidence had a very similar course. The variables that were both biologically meaningful and statistically significant in both regression models were the prevalence in pork sampled 4 to 5 weeks before case registration, the seroprevalence, measured as the average prevalence of week 15 to 35 before case registration, and the air temperature lagged at 2 and 3 weeks. Limitations on inferences from overall surveillance data are discussed.
Abattoirs↗
Seasonal variation in mortality in Scotland.
BACKGROUND: Seasonal patterns in mortality have been recognized for many years. This study assesses seasonal variation in mortality in Scotland between 1981 and 1993 and considers its association with socioeconomic status and outdoor temperature. METHODS: Lagged Poisson regression analysis of numbers of deaths and average weekly temperature with adjustment for serial autocorrelation and influenza epidemics. RESULTS: There was significant seasonal variation in weekly death rates with a difference of about 30% between a summer trough and a winter peak. This variation was principally attributable to respiratory disease, cerebrovascular disease and coronary artery disease. Seasonal variation in mortality fell from around 38% in 1981-1983 to around 26% in 1991-1993. There was no clear evidence of a relationship between socioeconomic status and seasonal mortality, however the extent of the fall in seasonal variation was greater in deprived areas than in affluent areas. Overall, a 1 degree C decrease in mean temperature was associated with a 1% increase in deaths one week later. The lag in this relationship varied by cause of death and underlying temperature. CONCLUSIONS: Seasonal variations in mortality and the relationship between temperature and mortality are a significant public health problem in Scotland. It is likely that the strength of this relationship is a result of the population being unable to protect themselves adequately from the effects of temperature rather than the effects of temperature itself.
Adolescent↗
Seasonal variation in gonorrhoea.
Seasonal variations in the incidence of gonorrhoea were observed in the 1970's with a peak in the third quarter of the year and a trough in the first and fourth quarters. The aim of this study was to determine what, if any, seasonal trends were present in Scotland and Lothian between 1984 and 1989 and postulate mechanisms to explain our observations. We observed a change in the previously reported pattern with regular peaks of infection in the first and third quarters of the year for Scotland but no regular trend in the Lothian region. The most likely explanation for the observed trends are changes in sexual behaviour related to summer vacations and seasonal work patterns but other unidentified factors probably also contribute.
Female↗
Characteristics of UVA-induced delayed tanning: seasonal variation.
We studied seasonal variation in UVA-induced delayed tanning and compared it to that in UVA + B-induced delayed tanning. The minimal tanning dose (MTD) and the minimal melanogenic dose (MMD) were determined one week after UVA exposure or UVA + B exposure, respectively. The MTD determined in the summer (June to August) was significantly higher than that in winter (December to February). In addition, while MTD in the winter correlated well with skin color, there was no correlation between MTD and skin color in summer. MTD tended to correlate with self-reported tanning history at the initiation of tanning in the winter, but they were not correlated with each other in the summer. The MMD measured in the summer was significantly lower than that in the winter. MMD correlated well with skin color in both seasons; the lighter the skin, the smaller the MMD. Also, a correlation was detected between MMD and self-reported tanning history. These results suggest that the susceptibilities of delayed tanning to UVA and UVA + B are affected by different factors.
Adult↗
Seasonal variation in meningococcal disease in Denmark: relation to age and meningococcal phenotype.
Seasonal variation has been shown in meningococcal disease (MD), but it is not known whether seasonal variation depends on age, gender and meningococcal phenotype. Based on complete registration of MD in North Jutland County, Denmark, during 1980-1999 (n = 413 cases), a Poisson regression model of a sinusoidal form was used to examine: (i) whether the seasonal variation in MD follows a sinusoidal pattern; (ii) the magnitude of seasonal variation in MD; and (iii) whether seasonal variation is related to age and gender and meningococcal phenotype. The peak-to-trough ratio (PTR) was used as a measure of the magnitude of seasonal variation. An overall seasonal variation in MD was found [PTR 2.0, 95% confidence interval (95% CI) 1.5-2.6]. There were differences between age groups and between phenotypes, but not between genders. The highest PTRs were observed for the age groups 5-9 y (PTR 4.9, 95% CI 2.1-11.9) and 10-14 y (PTR 3.7, 95% CI 1.4-9.7). No seasonal variation was found for children < 1 y (PTR 1.4, 95% CI 0.6-3.2) or teenagers 15-19 y (PTR 1.6, 95% CI 0.8-3.0). Among phenotypes the highest PTR was observed for C:2a:P1.2,5 (PTR 3.8, 95% CI 1.3-11.2). Thus, seasonal variation depended on age and meningococcal phenotype, the most pronounced seasonality being in 5-14-y-olds and in cases with phenotype C:2a:P1.2,5.
Adolescent↗
Seasonal variation in the frequency of Helicobacter pylori infection: a possible cause of the seasonal occurrence of peptic ulcer disease.
OBJECTIVES: The seasonal variation of duodenal ulcer disease and its complications have been repeatedly demonstrated in Israel by several independent studies. The aim of this study was to determine possible seasonal variations in the occurrence of H. pylori infection among dyspeptic patients in Israel. METHODS: All 14C-urea breath tests performed in dyspeptic patients at the gastroenterology department in the Tel Aviv Medical Center from January 1991 to December 1992 were reviewed. The monthly variation in the proportion of patients with H. pylori infection was determined, and compared with that of an unrelated 14C-cholyl-glycine breath test. RESULTS: Altogether, 702 patients were examined, and 371 (52.8%) of them were found to be infected with H. pylori. During summer months (July-September), a significant decrease in the percentage of patients infected with H. pylori was found, compared with winter months (December-January, 42.3% vs. 60.9%, p < 0.007). No seasonal variation was found in the results of 14C-cholyl-glycine test. The fluctuations in H. pylori infection were highly correlated with the seasonal occurrence of peptic ulcer disease in Israel. CONCLUSIONS: The frequency of H. pylori infection in dyspeptic patients in Israel is significantly increased during the winter months and decreased in the summer. This seasonal variation is identical to that found in duodenal ulcer disease. Thus, the seasonal variation of peptic ulcer disease could be explained by H. pylori infection, as seen in other communicable infectious diseases.
Breath Tests↗
[Seasonal variation of intraocular pressure after trabeculotomy].
The author reviewed the seasonal variation of intraocular pressure (IOP) in primary open angle glaucoma or late type developmental glaucoma to investigate possible relationships among seasonal variation of IOP, progression of visual field defects and the follow-up period between 53 eyes of 39 subjects with successful trabeculotomy (trabeculotomy group) and 45 eyes of 31 subjects with only medication (no operation group). IOPs in both groups were inclined to be low in summer and high in winter. Maximum seasonal variation of IOP and standard deviation of IOP during all follow-up periods which showed the degree of seasonal variation of IOP had no significant difference between the trabeculotomy group and the no operation group. These results showed that seasonal variation of IOP was not reduced even by successful trabeculotomy. The maximum seasonal variation of IOP and standard deviation of IOP had a tendency to be bigger in cases with progression of visual field defects than in cases with no progression of visual field defects, in both groups. Therefore, seasonal variation of IOP may be an important factor influencing the progression of visual field defects.
Follow-Up Studies↗