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PubMed2000

Influence of season and low-level oestradiol immunoneutralization on episodic LH and testosterone secretion and testicular steroidogenic enzymes and steroidogenic acute regulatory protein in the adult ram.

The regulation of LH-dependent and -independent increases in testosterone secretion by key proteins in the testes of adult rams was investigated. Serial blood samples were collected from groups of four control and passively immunized (oestradiol antiserum for 3 weeks) rams and the animals were gonadectomized in either the non-breeding season (April) or the breeding season (September). LH pulse frequency and basal (interpulse) concentrations were several times greater (P < 0.01) in the breeding season than in the non-breeding season. Neither of these parameters nor LH pulse amplitude were affected by oestradiol immunization. Parameters of testosterone episodic secretion and response to an injection (i.v.) of 15 micrograms NIH-LH-S25 were also greater (P < 0.05) in the breeding season and, with the exception of pulse frequency, in immunized rams versus controls. Substrate utilization established that testosterone biosynthesis was predominantly via the 5-ene pathway. Increases in blood testosterone concentration in the breeding season were associated with a fivefold higher (P < 0.01) activity of cytochrome P450 17alpha-hydroxylase/C-17,20 lyase (P450(17alpha)) and a 65% higher (P < 0.05) relative amount of mRNA for cytochrome P450 cholesterol side-chain cleavage enzyme complex (P450scc) in the testis. Of the steroidogenic enzyme activities examined, only that for 17beta-hydroxysteroid dehydrogenase (17beta-HSD) tended to be increased by oestradiol immunization. Blood concentrations of cholesterol lipoproteins and expression of the testicular low density lipoprotein receptor were not affected by season or immunization. The amount of steroidogenic acute regulatory protein (StAR) mRNA was 65% higher (P < 0.01) in the breeding season and 20% higher (P < 0.01) in immunized rams versus controls. These results indicate that greater LH stimulation may increase testosterone biosynthesis in the breeding season by increasing StAR mRNA (and presumably delivery of cholesterol to P450scc) and the activity of P450(17alpha), and possibly that of P450scc (activity not measured). More moderate increases in StAR mRNA and 17beta-HSD activity may explain, in part, the increases in testosterone secretion with oestradiol immunization.

17-Hydroxysteroid Dehydrogenases↗
PubMed2002

Surveillance for influenza--United States, 1997-98, 1998-99, and 1999-00 seasons.

PROBLEM/CONDITION: In the United States, influenza epidemics occur nearly every winter and are responsible for substantial morbidity and mortality, including an average of approximately 114,000 hospitalizations and 20,000 deaths/year. REPORTING PERIOD: This report summarizes both actively and passively collected U.S. influenza surveillance data from October 1997 through September 2000. DESCRIPTION OF SYSTEM: During each October-May in the period covered, CDC received weekly reports from 1) approximately 120 World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories in the United States regarding influenza virus isolations; 2) approximately 230, 375, and 430 sentinel physicians during 1997-98, 1998-99, and 1999-00, respectively, regarding their total number of patient visits and the number of visits for influenza-like illness (ILI); and 3) state and territorial epidemiologists regarding estimates of local influenza activity. WHO collaborating laboratories also submitted influenza isolates to CDC for antigenic analysis. Throughout the year, the vital statistics offices in 122 cities reported weekly on deaths related to pneumonia and influenza (P&I). RESULTS: During the 1997-98 influenza season, influenza A(H3N2) was the most frequently isolated influenza virus type/subtype. Influenza A(H1N1) and B viruses were reported infrequently. The proportion of respiratory specimens testing positive for influenza peaked at 28% in late January. The longest period of sustained excess mortality (when the percentage of deaths attributed to P&I exceeded the epidemic threshold) was 10 consecutive weeks. P&I mortality peaked at 9.8% in January. Visits for ILI to sentinel physicians exceeded baseline levels for 7 weeks and peaked at 5% in mid-January through early February. A total of 45 state epidemiologists reported regional or widespread activity at the peak of the season. During the 1998-99 season, influenza A(H3N2) viruses predominated; however, influenza B viruses were also identified throughout the United States. Influenza A(H1N1) viruses were identified rarely. The proportion of respiratory specimens testing positive for influenza peaked at 28% in early February. P&I mortality exceeded the epidemic threshold for 12 consecutive weeks and peaked at 9.7% in early March. Visits for ILI to sentinel physicians exceeded baseline levels for 7 weeks and peaked at 5% in early through mid-February. Forty-three state epidemiologists reported regional or widespread activity at the peak of the season. During the 1999-00 season, influenza A(H3N2) viruses predominated, but influenza A(H1N1) and B viruses also were identified. The proportion of respiratory specimens testing positive for influenza peaked at 31% in mid- to late December. The proportion of deaths attributed to P&I exceeded the epidemic threshold for 13 consecutive weeks and peaked at 11.2% in mid-January. Visits to sentinel physicians for ILI exceeded baseline levels 4 consecutive weeks and peaked at 6% in late December. Forty-four state epidemiologists reported regional or widespread activity at the peak of the season. INTERPRETATION: Influenza A(H1N1), A(H3N2), and B viruses circulated during 1997-2000, but influenza A(H3N2) was the most frequently reported virus type/subtype during all three seasons. Influenza A(H3N2) is the virus type/subtype most frequently associated with excess P&I mortality. Influenza activity during all three seasons occurred at moderate to severe levels, and excess P&I mortality was reported during > or = 10 weeks each year. PUBLIC HEALTH ACTIONS: CDC conducts active national surveillance during each October-May to detect the emergence and spread of influenza virus variants and to monitor influenza-related morbidity and mortality. Surveillance data are provided weekly throughout the influenza season to public health officials, WHO, and health-care providers and are used to guide vaccine strain selection, prevention and control activities, and patient care. Influenza vaccination is the most effective means for reducing the yearly effect of influenza. Typically, one or two of the influenza vaccine component viruses are updated each year so that vaccine strains will closely match circulating viruses. Surveillance data will continue to be used to select vaccine strains and to monitor the match between vaccine strains and the currently circulating viruses.

Disease Outbreaks↗
PubMed2003

[Effects of cropping systems on nitrous oxide emissions from paddy soils during the rice-growing season].

Cropping systems influence nitrous oxide (N2O) emissions from agricultural soils. Effects of 3 rice-based cropping systems on N2O emissions from paddy soils in pot experiment were investigated with closed chambers in triplicate. The results demonstrated that the seasonal N2O emission rate of the rice pot under rice-wheat cropping system was obviously higher than that of the early rice pot under double rice-wheat system, being 4.21 and 2.17 kg.hm-2, respectively. No distinct difference was observed between the seasonal average fluxes, which were 116.9 and 117.6 micrograms.m-2.h-1 respectively. Both of above mentioned seasonal average fluxes were greatly higher than that of the late rice pot under early rice-late rice-wheat cropping system and of rice pot under rice-flooding fallow system, being 67.0 and 42.1 micrograms.m-2.h-1 respectively. More than 91% of the seasonal emission was focused on the first half growing period both in the rice season in rice-wheat system and in the early rice season in double rice-wheat system in which the previous cropping was upland wheat. 91% of the seasonal emission was focused on the water drainage period including the mid-season aeration and final drainage in the late rice season in double rice-wheat system in which the previous cropping was lowland rice. The results implied that cropping system and water status of previous cropping impacted N2O emission from paddy soil.

Crops, Agricultural↗
PubMed2004

[Seasonal depressive disorder: a controlled study in Tunisian psychiatric sample].

Seasonal affective disorder is considered as a clinical subtype of major depression. The criteria for seasonal pattern has been recently described in the international classification of mental disorders. The aim of this study was to compare the clinical characteristics of patients with major depression and with a seasonal and a non seasonal pattern. The study was conducted at the psychiatric ward at Monastir university hospital. 16 inpatients with major depression and seasonal pattern, diagnosed with DSM-IV criteria, were matched in age, sex and diagnostic sub-type to 32 inpatients with non seasonal mood disorders. Clinical symptoms and short term course during the most recent depressive episode were obtained. The onset of the depression with seasonal pattern was frequently in winter. It was marked by significantly higher rates of anxiety. The patients with seasonal depression had significantly higher rates of dysphoria, atypical vegetative symptomatology and lower rates of psychotic characteristics and suicidal thoughts. No differences were found as to the psychiatric family histories or the age at the first depressive episode. This study could focus of the novel psychiatric entity and may lead to the development of the genetic and neurobiologic research related to seasonal affective disorder.

Adult↗
PubMed2005

Seasonal variations of selected cardiovascular risk factors.

This article reviews research on selected biomarkers of cardiovascular risk - cholesterol and other lipids, C-reactive protein (CRP), fibrinogen, homocysteine - in the attempt to determine the existence of a predictable seasonal chronobiological pattern of variation. Studies dating as far back as the 1930s have reported seasonal variations in cholesterol levels. Statistically significant seasonal changes in lipid levels have been found in individuals irrespective of the country where the research has been conducted, and irrespective of the age, sex, ethnicity, and baseline lipid levels of the study subjects. While not all studies have been in complete agreement on either the amplitude (degree of seasonal change) or month/s of highest lipid levels, a strong winter/summer difference has been found in most studies. Existing evidence for an independent effect of season in variation of CRP is weak. Studies have consistently reported significant seasonal variations in fibrinogen levels. While other biological factors clearly interact to affect fibrinogen variability, seasonality appears to be an independent source of variability. Evidence from several studies points to a lack of seasonal variability in homocysteine levels. Although seasonal variability is just one source of periodicity influencing biological function and assessments in clinical practice, for some biomarkers, including lipids and fibrinogen, it is a source of variability that warrants consideration prior to a decision to treat and in assessing response to interventions.

Biomarkers↗
PubMed1989

Biosocial responses to seasonal food stress in highland Peru.

This paper examines patterns of seasonal variation in food consumption and responses to food stress in the highland community of Nuñoa, Peru. Dietary and anthropometric data collected from January through August of 1985 on a sample of 26 households (127 individuals) are analyzed. This study finds sharp seasonal differences in energy intake (pre-harvest = 1150 calories/day; post-harvest = 1519/day; p less than 0.01) associated with variation in the availability of locally-produced products (e.g., tubers and cereals). Seasonal energy reduction, however, does not uniformly affect all sectors of this population. Children experience little seasonal change in energy intake and have a more adequate pre-harvest diet and better nutritional status than adults. The responses used to "protect" children from energy stress and minimize the overall impact of seasonal food scarcity on this community include: 1) reduction of pre-harvest household caloric needs through emigration of adolescent and adult males, 2) preferential allocation of food to children during the pre-harvest period, 3) seasonal reduction of activity levels and the year-round use of children for many productive activities, and 4) seasonal changes in meal patterns that minimize post-prandial energy loss during periods of stress. Evaluation of similar data from other anthropological populations underscores the diversity of responses to seasonal change in food availability. Moreover, these data indicate that the protection of children from seasonal energy stress is more common than previously thought. Variation in adaptive responses to food stress appears to be dependent upon 1) the nature of the subsistence economy, 2) the relative contributions of children and adults to household production, and 3) the demographic structure of the population.

Adolescent↗
PubMed1987

Food consumption patterns in a rural Tanzanian community (Kikwawila village, Kilombero District, Morogoro Region) during lean and post-harvest season.

A survey on food consumption was undertaken in 32 out of 260 households of a rural Tanzanian community (Kikwawila village, Morogoro Region) during the lean season (February) and the post-harvest season (August) in 1983. The survey revealed that the staples maize, rice and cassava are equally important food items of the diet during the lean season. In August, the post-harvest season, rice dominated the food pattern and often replaced the porridge made from maize or cassava. Green vegetables, especially cassava leaves, were the main relish dish for the majority of households in February. Fish became a daily item of the diet of most families in August. Concentrated energy sources such as fats, oil and sugar were scarce in both survey periods. The diets of all age groups of the population surveyed were highly deficient in energy (mean adequacy 58%) and protein (50%) in February. The FAO/WHO-recommended standards (Passmore et al., 1974) were met for protein in August but energy deficiency was still observed (mean adequacy 65%). The variations in energy intake were not only seasonal, but were also age and sex dependent. Young males (10 to 16 years) followed by the infants (6 months to 3 years) and old females (greater than 60 years) were the groups with lowest adequacy (less than 50%) in February. Males (10 to 60 years) had the greatest energy deficits in August. Iron requirements were generally met in most age groups during both seasons. However, children under 3 years as well as adolescent and adult females (mean adequacy 54-65% in August) were at risk for anaemia. The seasonal pattern of the diet did significantly influence the vitamin A intake. While the requirements were fully met in February, a deficiency was noted in August. The low adequacy (40%) for vitamin A during the post-harvest season could be related to the scarcity of leafy vegetables in the diets. The data are discussed and related to the health problems observed in the community during the post-harvest season for three consecutive years.

Adolescent↗
PubMed1995

Psychological distress and seasonal symptom changes in irritable bowel syndrome.

OBJECTIVE: It is not known whether irritable bowel syndrome (IBS) fluctuates with the seasons. We aimed to determine whether seasonal changes in symptoms occur in IBS and to examine the relationships between IBS, seasonality, and psychological factors. METHODS: A random sample of the community (n = 99) and hospital staff volunteers (n = 163) in Sydney, Australia, completed a previously validated questionnaire that measured bowel symptoms, psychosocial factors, and seasonality. RESULTS: IBS (n = 60; 23%) was significantly associated with somatization (by the Psychosomatic Symptom Checklist) and lifetime depression but not neuroticism (by the Eysenck Personality Questionnaire) or psychological morbidity (by the General Health Questionnaire). A seasonal variation in behavior score (measuring sleep, eating, including carbohydrate craving, weight gain, socializing, energy level, and mood by the Seasonal Pattern Assessment Questionnaire) was associated with somatization (p < 0.001) and IBS (p < 0.05) in a stepwise multiple regression model. Of those with IBS, 23% reported moderate or greater seasonal change in bowel symptoms. Subjects with IBS (vs subjects with some bowel symptoms) were significantly more likely to report seasonal changes in pain and/or disturbed defecation (odds ratio = 3.2; 95% CI = 1.25-8.23); the latter was significantly associated with somatization but not the other psychological variables. CONCLUSIONS: A subset of IBS may be seasonally determined, and this is explained in part by somatization.

Adult↗
PubMed1996

Measles vaccination during the respiratory virus season and risk of vaccine failure.

OBJECTIVE: To determine whether measles vaccine failure is more common in persons who were vaccinated during the respiratory virus season, when they were more likely to have had concurrent minor illnesses. DESIGN: Population-based case series and case-control study. SETTING: Wisconsin and Ohio. SUBJECTS: The case series included all 545 of the states' residents who had confirmed measles reported during 1985 through 1990 and a history of receiving a single dose of measles vaccine during 1975 through 1988 at 15 to 59 months of age. In a case-control study restricted to 1984 through 1988 vaccinees, season of vaccination was compared in 170 case children and 6070 control students. MAIN OUTCOME MEASURE: Risk of clinical vaccine failure after measles vaccination during the respiratory virus season (September through May) or the peak season (November through March) compared with summertime (June through August), after adjustment for age at vaccination and place of residence. RESULTS: In the case series of persons with vaccine failure, the proportion who had been vaccinated during the respiratory virus season (74.7%) was no greater than expected (September through May = 74.8% of the year). In the case-control study, vaccination during the respiratory virus season (odds ratio, 0.92; 95% confidence interval, 0.66 to 1.30) or the peak season (odds ratio, 0.93) did not increase the risk of vaccine failure. CONCLUSION: Despite the high and strongly seasonal prevalence of viral respiratory illness in young children, routine childhood measles vaccination during the respiratory virus season does not increase their risk of vaccine failure. Findings provide epidemiologic support for recently strengthened recommendations that measles vaccination not be deferred in children with minor respiratory illnesses.

Antibody Formation↗
PubMed1981

Relationship between doses of prostaglandin F2alpha and stages of the breeding season for synchronization of estrus and ovulation in ewes.

Two experiments were conducted to compare estrous response to three doses (8, 16 and 24 mg) of prostaglandin F2alpha (PGF2alpha) administered by intramuscular injection to ewes between day 6 and 12 of the estrous cycle (Experiment I) and to ewes on unknown days of the estrous cycle during four different stages of the breeding season (Experiment II). In experiment I, a total of 41 ewes were treated with PGF2alpha. The injection of 24 mg PGF2alpha resulted in a higher proportion of ewes exhibiting estrus (13/14, 92.9%) within 5 days after treatment as compared to the other two doses (2/12 and 10/15, for 8 and 16 mg PGF2alpha, respectively). However, there was no significant difference for the proportion between 16 mg and 24 mg PGF2alpha. In experiment II, PGF2alpha was given to ewes on the 3rd of February (early breeding season), the 28th of February (mid-early breeding season), the 10th of April (mid breeding season) and the 27th of May (late breeding season). These was a significant difference for the proportion of ewes exhibiting estrus between the early breeding season and the other three seasons (P<0.05) but not for ewes ovulating. Throughout the breeding season, 16 mg PGF2alpha appeared to be slightly better than the other two doses (8 and 24 mg) although there was no overall difference in the estrous responses to treatment among the three doses. However, a significant difference in the proportion of ewes ovulating was found among the three doses of PGF2alpha (P<0.05). Especially, 16 mg PGF2alpha was significantly superior to 8 mg (P<0.01) and 24 mg (P<0.05). It was considered that there was a complicated relationship between the doses of PGF2alpha and the stages of the breeding season for induction of estrus and ovulation in the ewe.

Journal Article↗
PubMed2006

Risk of hospitalization during influenza season among a cohort of patients with congestive heart failure.

It is uncertain whether hospitalization among patients with congestive heart failure (CHF) increases during the influenza season. This retrospective cohort study used influenza surveillance data from the United States (1986-1987 to 1990-1991), clinical information from the Studies of Left Ventricular Dysfunction (SOLVD) database, and daily temperature data from the National Climatic Data Center to assess the effect of influenza season on hospitalizations in this cohort of patients. The overall hospitalization rate was higher during influenza seasons compared to non-influenza seasons [relative risk (RR) 1.08, 95% confidence interval (CI) 1.01-1.16]. Multivariable Cox modelling revealed an adjusted hazard ratio (HR) of 1.11 for hospitalization during the influenza season (95% CI 1.03-1.20, P=0.005). Overall death rates were also higher during influenza seasons than non-influenza seasons (RR 1.09, 95% CI 0.97-1.21), but the corresponding adjusted HR for death was not significant (HR 1.01, 95% CI 0.98-1.24, P=0.11). Patients with CHF have a greater risk of hospitalization during the influenza season than in the non-influenza season, supporting the current belief that patients with CHF should be regarded as a high-risk group.

Cohort Studies↗
PubMed1985

Some effects of breeding season and castration on the prostate and epididymis of the brushtail possum, Trichosurus vulpecula.

In an attempt to understand the mechanism(s) responsible for the reported marked seasonal increase in prostatic, but not epididymal, weight in T. vulpecula, a number of parameters were measured in tissues from mature, entire males sampled within and outside of the breeding season and from castrates. Conditions for the measurement of cytosol androgen receptors were also established. The weight of both the prostate and the epididymis was significantly elevated in the breeding season but the relative increase in prostate weight was considerably greater. The increase in prostatic weight was associated with a decrease in DNA: g tissue and an increase in protein: DNA and RNA: DNA ratios, each indicative of cellular hypertrophy and/or accumulation of secretory product. In the epididymis there were no significant seasonal changes in RNA: DNA, protein: DNA or DNA: g tissue ratios. Low-capacity, high-affinity binding was demonstrated in the epididymal and prostatic cytosols and values for the equilibrium association constants and receptor concentrations were within the range reported for androgen receptors in eutherian species. The temperature sensitivity of the binding, steroid specificity and slow dissociation in the cold indicated that in both tissues cystosol receptor and not androgen-binding or serum-binding protein(s) were being measured. In prostatic, but not epididymal, cytosol a low level of progesterone binding was observed and was masked by triamcinolone acetonide. When expressed in terms of tissue DNA, cytosol androgen receptor level in the prostate only was elevated in the breeding season. Prostatic tissue showed a low level of 5 alpha-reductase in vitro which was not influenced by season. However, both tissues showed a high concentration of 5 alpha-dihydrotestosterone and in the prostate, where seasonal effects were measured, the concentration was higher in the breeding season. This indicates that although 5 alpha-dihydrotestosterone is the likely active androgen in the prostate it may be formed elsewhere. Part of the explanation for the increased growth of the prostate in the breeding season appears to be a change in receptor concentration coupled with elevated tissue androgen level.

Androgen-Binding Protein↗
PubMed2002

The effectiveness of influenza vaccine against influenza a (H3N2) virus infections in nursing homes in Niigata, Japan, during the 1998-1999 and 1999-2000 seasons.

OBJECTIVE: To evaluate the effectiveness of influenza vaccines against influenza-like illness (ILI) among nursing home residents. DESIGN: Prospective, nonrandomized, cohort study. SETTING: Nine nursing homes during the 1998-1999 influenza season and 11 nursing homes during the 1999-2000 influenza season in Niigata Prefecture, Japan. PARTICIPANTS: Six hundred ninety-nine residents and 440 healthcare workers (HCWs) during the first season, and 930 residents and 517 HCWs during the second season, with vaccination rates ranging from 0% to 97.7%. RESULTS: Overall, ILI decreased from 24.3% during the 1998-1999 season to 8.8% during the 1999-2000 season. Multivariate analysis adjusted for several factors, including gender, age, underlying diseases, and resident and HCW vaccination rates, failed to demonstrate clear individual protection of residents (relative risk [RR], 1.42; P = .2 for the first season; RR, 0.95; P = .9 for the second season). However, vaccination rates of 60% or greater for residents and HCWs reduced the risk of ILI, and also could prevent outbreaks during the 2 seasons. Highly impaired activities of daily living and chronic respiratory diseases were significantly associated with increased ILI. CONCLUSIONS: A high vaccination rate for both residents and HCWs may reduce the risk of ILI and institutional outbreaks in nursing homes.

Aged↗
PubMed2000

Seasonal CO(2) assimilation and stomatal limitations in a Pinus taeda canopy.

Net CO(2) assimilation (A(net)) of canopy leaves is the principal process governing carbon storage from the atmosphere in forests, but it has rarely been measured over multiple seasons and multiple years. I measured midday A(net) in the upper canopy of maturing loblolly pine (Pinus taeda L.) trees in the piedmont region of the southeastern USA on 146 sunny days over 36 months. Concurrent data for leaf conductance and photosynthetic CO(2) response curves (A(net)-C(i) curves) were used to estimate the relative importance of stomatal limitations to CO(2) assimilation in the field. In fully expanded current-year and 1-year-old needles, midday light-saturated A(net) was constant over much of the growing season (5-6 &mgr;mol CO(2) m(-2) s(-1)), except during drought periods. During the winter season (November-March), midday A(net) of overwintering needles varied in proportion to leaf temperature. Net CO(2) assimilation at light saturation occurred when daytime air temperatures exceeded 5-6 degrees C, as happened on more than 90% of the sunny winter days. In both age classes of foliage, winter carbon assimilation accounted for approximately 15% of the daily carbon assimilation on sunny days throughout the year, and was relatively insensitive to year-to-year differences in temperature during this season. However, strong stomatal limitations to A(net) occurred as a result of water stress associated with freezing cycles in winter. During the growing season, drought-induced water stress produced the largest year-to-year differences in seasonal CO(2) assimilation on sunny days. Seasonal A(net) was more drought sensitive in current-year needles than in 1-year-old needles. Relative stomatal limitations to daily integrated A(net) were approximately 40% over the growing season, and summer drought rather than high temperatures had the largest impact on summer A(net) and integrated annual CO(2) uptake in the upper crown. Despite significant stomatal limitations, a long duration of near-peak A(net) in the upper crown, particularly in 1-year-old needles, conferred high seasonal and annual carbon gain.

Journal Article↗
PubMed2006

Haematological parameters in elite rugby players during a competitive season.

We assessed haematological parameters and possible modifications in elite rugby players throughout a competitive season for increasing the knowledge of physiological characteristics of these sportsmen. Blood samples were collected from the members of the Italian National rugby team at four consecutive training camps during a whole competitive season. Forty-four athletes were recruited for the first camp, 36 for the second, 30 for the third and 32 for the fourth. Due to turnover of the subjects during the season only 13 athletes could be examined at all four camps, and another six in the first three camps. Therefore, we selected the data of these 19 athletes. Iron and transferrin saturation were stable, whilst ferritin increased at the end of the season. The modifications of the soluble transferrin receptor (sTFR) were linked to those of haematocrit: sTFR increased after training and during the competition period when haemoglobin and haematocrit decreased, and decreased at the end of the season. Haemoglobin and haematocrit showed slightly higher levels during the first part of the season and decreased in the second half, when physical demand was high, as demonstrated by biochemical additional tests. Leucocytes and platelets were stable throughout the season. Haematological and iron metabolism parameters in the elite rugby players examined during a whole season fall within physiological range of values. The variability of the parameters during the season is related to training and competition workload. Reticulocytes and sTFR are the most sensitive parameters for studying the iron metabolism of the athletes.

Analysis of Variance↗
PubMed2000

Seasonal variation in rates of methane production from peat of various botanical origins: effects of temperature and substrate quality.

The methane produced in peat soils can vary over the growing season due to variations in the supply of available substrate, the activity of the microbial community or changes in temperature. Our aim was to study how these factors regulate the methane production over the season from five different peat types of different botanical origin. Peat samples were collected on seven occasions between June and September. After each sampling, the peat soils were incubated at five different temperatures (7, 10, 15, 20 and 25 degrees C) without added substrate, or at 20 degrees C with added substrate (glucose, or H(2)/CO(2), or starch). Rates of methane production averaged over the season differed significantly (P<0.05, R(2)=0.76) among the five peat types, the minerotrophic lawn producing the highest rates, and the hummock peat producing the lowest. The seasonal average Q(10) values for each plant community varied between 4.6 and 9.2, the highest value being associated with the ombrotrophic lawn and the lowest value with the mud-bottom plant community. For the unamended peat samples, the rates of methane production from each plant community varied significantly (P<0.05) over the season. This implies that the quality of organic matter, in combination with changes in temperature, explains the seasonal variation in methane production. However, addition of saturating amounts of glucose, H(2)/CO(2) or starch at 20 degrees C significantly reduced the seasonal variation (P<0.05) in methane production in peat from the minerotrophic lawn, wet carpet and mud-bottom plant communities. This suggests that substrate supply (e.g. root exudates) for the micro-organisms also varied over the season at these sites. Seasonal variation in methane production rates was apparent in peat from the hummock and ombrotrophic lawn plant communities even after addition of substrates, suggesting that the active biomass of the anaerobic microbial populations at these sites was regulated by other factors than the ones studied.

Journal Article↗
PubMed2004

Nonoperative management for in-season athletes with anterior shoulder instability.

BACKGROUND: Acute or recurrent anterior shoulder instability is a frequent injury for in-season athletes. Treatment options for this injury include shoulder immobilization, rehabilitation, and shoulder stabilization surgery. PURPOSE: To determine if in-season athletes can be returned to their sports quickly and effectively after nonoperative treatment for an anterior instability episode. METHODS: Over a 2-year period, 30 athletes matched the inclusion criteria for this study. Nineteen athletes had experienced anterior dislocations, and 11 had experienced subluxations. All were treated with physical therapy and fitted, if appropriate, with a brace. These athletes were followed for the number of recurrent instability episodes, additional injuries, subjective ability to compete, and ability to complete their season or seasons of choice. RESULTS: Twenty-six of 30 athletes were able to return to their sports for the complete season at an average time missed of 10.2 days (range, 0-30 years). Ten athletes suffered sport-related recurrent instability episodes (range, 0-8 years). An average of 1.4 recurrent instability episodes per season per athlete occurred. There were no further injuries attributable to the shoulder instability. Sixteen athletes underwent surgical stabilization for their shoulders during the subsequent off-season. CONCLUSIONS: Most of the athletes were able to return to their sport and complete their seasons after an episode of anterior shoulder instability, although 37% experienced at least 1 additional episode of instability during the season.

Adolescent↗
PubMed1996

Seasonal mood disturbances in collegiate hockey players.

OBJECTIVE: THE PURPOSE OF THIS PAPER IS TO: 1) describe the seasonal affective disorder syndrome using a case illustration, 2) provide a simple and reliable method for identifying seasonal affective disorder, and 3) provide data as to the prevalence of the syndrome in a subset of collegiate hockey players. DESIGN AND SETTING: Collegiate hockey players were selected, because their practices begin in the fall and play is completed in the spring. The teams selected for participation were from the far Northwest and the upper Midwest regions. SUBJECTS: Sixty-eight Division I hockey players volunteered for the study. The three teams from which the subjects were chosen were located above latitude 42 degrees /45' north. Subjects were from the northern latitudes. MEASUREMENTS: The Seasonal Pattern Assessment Questionnaire was used to screen for seasonality. A sample of the athletes was also examined using the Hamilton Rating Scale for Depression together with the Diagnostic and Statistical Manual of Mental Disorders (4th ed) criteria for Seasonal Pattern Specifier. RESULTS: Thirty-three (51%) were asymptomatic, 7 (11%) met the criteria for seasonal affective disorder, and 25 (39%) hockey players scored in the range that could classify them as candidates for subsyndromal seasonal affective disorder. CONCLUSIONS: The prevalence of seasonal affective disorder among our sample approximated the national norm for the northern latitudes. However, the prevalence of subsyndromal seasonal affective disorder in our population was 25% compared to 13% reported nationally. Light therapy has been shown to reverse the effects of the disorders; however, further research needs to be conducted to determine its acceptance and effectiveness by the athletic population.

Journal Article↗