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PubMed1983

Male sexual development in the monkey. I. Cross-sectional analysis of pulsatile hypothalamic-pituitary-testicular function.

Pulsatile secretion of serum gonadotropins and testosterone was studied in 46 monkeys of varying ages from 9 days of age through adult life. Although some of the hormonal analysis was longitudinal in nature, most comparisons were cross-sectional. On the basis of pulsatile secretory patterns, hCG and GnRH stimulation, skeletal age, testicular volume, and histology, we have arbitrarily defined four developmental age groups: postnatal (less than 7 months), prepubertal or juvenile (7-27 months), pubertal (28-59 months), and adult (greater than or equal to 60 months). In accomplishing the pulsatile studies, blood was withdrawn at 15-min intervals over 24 h without anesthesia using a mobile vest and tether assembly to support an indwelling cannula. GnRH and hCG challenge tests were done on one or more occasions on all animals. Plasma samples were analyzed for concentrations of FSH, LH, testosterone, dihydrotestosterone and delta 4-androstenedione by established RIAs and an in vitro bioassay for LH. During the frequent sampling period of 24-h duration for all except postnatal animals, testosterone pulses of large amplitude (up to 8-fold) occurred in postnatal, pubertal, and adult animals. Pulsatile gonadotropin secretion was seen at all ages; however, the highest pulses (up to 15-fold) occurred in prepubertal animals even though this was an infrequent occurrence. Time series analysis techniques were applied for objective statistical characterization of cyclic patterns. Basic rhythms corresponding to 50- to 90-min frequency cycles in gonadotropin secretion were identified. Substantive differences between LH concentrations by bioassay and RIA were seen infrequently. Our findings illustrate that: 1) circulating gonadotropin and testosterone pulses change in amplitude but not necessarily frequency during pubertal development, and 2) primate models are a useful paradym for the longitudinal study of human male sexual development. We conclude that where direct human investigation may be limited, much can be learned by study of these primate surrogates.

Age Determination by Skeleton↗
PubMed1988

Relationships of low density lipoprotein cholesterol with age and other factors: a cross-sectional analysis of the CARDIA study.

Presumed evolution of low density lipoprotein cholesterol (LDL-C) was studied in a baseline cross-sectional survey of 4955 18-30 year old men and women of various sociodemographic backgrounds. Specifically studied were the influences on LDL-C and the change of LDL-C with age of race, gender, education, diet, physical activity, fatness and fitness. Men increased about 20 mg/dl per 10 years of age, while women increased about 3 mg/dl. Increasing education was found to be associated with higher LDL-C in blacks, but with lower LDL-C in whites. Higher Keys diet score and body mass index were positively associated with LDL-C, while higher total caloric intake, vigorous physical activity, duration on a treadmill exercise test and usual intake of alcohol were negatively associated with LDL-C. The finding of a different relationship of LDL-C to increasing education in whites than in blacks suggests a cultural or behavioral influence in rate of increase in LDL-C.

Adolescent↗
PubMedDate not supplied

The shift from natural to controlled fertility: a cross-sectional analysis of ten Indian states.

This study investigates the causes of the transition from natural to controlled fertility in India by comparing couples who have ever used contraception with those who remained under natural fertility conditions. Using sample study data this paper considers the relative effects of the factors involved in the shift to controlled fertility among ten early-transitional Indian States in 1970. The results indicate that it is primarily improvements in child mortality and its effects through intervening factors that account for the transition. The implication is that the success of a family planning program is largely a function of improvements in child health.

Child, Preschool↗
PubMed2006

A longitudinal and cross-sectional analysis of total body oxygen store development in nursing harbor seals (Phoca vitulina).

This study compared the efficacy of longitudinal and cross-sectional sampling regimes for detecting developmental changes in total body oxygen (TBO(2)) stores that accompany behavioral development in free-ranging harbor seal pups. TBO(2) stores were estimated for pup (n = 146) and adult female (n = 20) harbor seals. Age related changes were compared between pups captured repeatedly during the lactation period (longitudinal dataset) and a second group of pups handled only once (cross-sectional dataset). At each handling, hematocrit, hemoglobin, red blood cell count, total plasma volume, blood volume, muscle myoglobin concentration, and blood and muscle oxygen stores were determined. Comparisons across age categories revealed newborn blood oxygen stores were initially elevated, declined to low values by early lactation, and increased through post-weaning. Muscle oxygen stores remained low and constant throughout lactation and only increased significantly post-weaning. Overall TBO(2)stores increased 17% during lactation, and weaned pups had TBO(2)stores that were 55% as large as those of adults. Thus, significant increases in TBO(2) stores must occur after weaning, as pups begin to forage independently. Results from the two sampling schemes did not differ, indicating that the logistically simpler cross-sectional design can be used to monitor physiological development in harbor seals.

Animals↗
PubMed2005

Neuropsychiatric symptoms of dementia: cross-sectional analysis from a prospective, longitudinal Belgian study.

OBJECTIVE: Given the rather limited knowledge on profiles of neuropsychiatric symptoms (behavioural and psychological signs and symptoms of dementia, BPSD) in several degenerative dementias, we designed a prospective study of which we here present the baseline data. METHODS: Diagnosed according to strictly applied clinical diagnostic criteria, patients with probable Alzheimer's disease (AD) (n = 205), frontotemporal dementia (FTD) (n = 29), mixed dementia (MXD) (n = 39) and dementia with Lewy bodies (DLB) (n = 23) were included. All patients underwent a neuropsychological examination and behavioural assessment by means of a battery of scales (Middelheim Frontality Score (MFS), Behave-AD, Cohen-Mansfield Agitation Inventory, Cornell Scale for Depression in Dementia). RESULTS: In AD and MXD, activity disturbances and aggressiveness occurred in more than 80% of the patients. With a prevalence of 70%, apathy was very common whereas delusions and hallucinations were rare in FTD patients. Frequently used behavioural assessment scales like the Behave-AD systematically underestimated BPSD in FTD whereas the MFS displayed high sensitivity for frontal lobe symptoms. Hallucinations discriminated DLB patients from other dementias. A high prevalence of disinhibition (65%) in DLB pointed to frontal lobe involvement. CONCLUSIONS: Behavioural assessment may help differentiating between different forms of dementia, further stressing the need for the development of new and more sensitive behavioural assessment scales. By means of the MFS, frontal lobe involvement was frequently observed in DLB. As 70% of FTD patients displayed apathy, prevalence was about two times higher compared to the other disease groups, meanwhile indicating that apathy is frequently observed in dementia, irrespective of its etiology.

Aged↗
PubMed2004

Cross-section analysis of organic light-emitting diodes.

The 'lift-out' technique using a focused ion beam microscope was applied to prepare cross-sectional specimens of organic light-emitting diodes for use in transmission electron microscopy. The focused ion beam equally thins the organic/inorganic hybrid devices despite the difference in material hardness of the compounds. This allowed to overcome preparation difficulties of conventional techniques such as ion thinning or ultra-microtomy. Two different samples were prepared and studied by both conventional transmission electron microscopy and analytical electron microscopy to display some of the investigation possibilities which become available with this sample preparation method.

Aluminum↗
PubMedDate not supplied

Propulsion technique and anaerobic work capacity in elite wheelchair athletes: cross-sectional analysis.

Wheelchair sports and daily manual wheelchair propulsion are dominated by frequent short-term power demands. The purpose of the current cross-sectional study was to determine the variation in propulsion technique in association with sprint power production among elite wheelchair athletes. Therefore, 67 wheelchair athletes (different impairments; 17 female and 50 male athletes; age, 29.1+/-7 yr; body weight, 60.7+/-11.8 kg; training hours, 12.9+/-6.4 h x wk(-1); VO2 peak, 1.7+/-0.7 liter x min(-1); aerobic power output, 72.2+/-36.7 W) were studied during the World Championships and Games for the Disabled in Assen (1990) on propulsion technique and anaerobic work capacity in a 30-s sprint test on a computer controlled wheelchair ergometer. Mean power output (P30) (97+/-45.8 W; range, 8.3-195.3 W) and heart rate (158.6+/-23.6 b x min(-1)) were highly variable and seemed associated with impairment level: track athletes, classified in four different functional classes, showed a class-related P30 of 23, 68, 100, and 138 W for the male athletes (n=38). Sprint power relative to body weight varied between 0.36 W X kg BW(-1)+/-0.04 and 1.85 W X kg BW(-1)+/-0.43 for the different subject groups. Propulsion technique in terms of forces applied to the rim and timing showed significant differences between subject groups for the majority of parameters studied. Apart from the mediolateral force and the negative dip at the start of the push phase, the technique parameters were significantly related to power production. Fraction effective force, the ratio between the total force vector and the effective force applied to the hand rim, appeared low on average (especially for subjects with cerebral palsy and those with a high spinal lesion) but showed a significant correlation with power output (r=0.5). In general, propulsion technique parameters were related to both performance and functionality. The number of training hours showed a small but significant relation with peak power (r=0.31), peak torque (r=0.4), the amount of work per push (r=0.41) and the total force vector (r=0.31), stressing the role of training status, next to disability, as important mediating factor in both propulsion technique as well as performance capacity. No association between training hours and fraction effective force was seen. It can be concluded that propulsion technique and performance parameters are highly variable among wheelchair athletes. Also, propulsion technique is strongly associated with functionality and training hours and does clearly relate to performance. The current results on technique and performance and their possible causal relationship, but also with impairment and sports discipline, must be further substantiated in a longitudinal study design.

Adult↗
PubMed2003

Iodine deficiency in urban primary school children: a cross-sectional analysis.

OBJECTIVE: To determine the prevalence of iodine deficiency in primary school children in an Australian urban population. DESIGN AND SETTING: A cross-sectional survey of school children aged 5-13 years attending a public school on the Central Coast of New South Wales in November 2000. PARTICIPANTS: 324 (70%) of the 465 children enrolled in the school (180 boys; 144 girls). MAIN OUTCOME MEASURES: Thyroid volumes compared with World Health Organization/International Council for the Control of Iodine Deficiency Disorders (WHO/ICCIDD) thyroid volume reference values. Iodine status based on WHO/ICCIDD urinary iodine concentration (UIC) categories (normal, >/= 100 microg per litre of urine [microg/L]; mild iodine deficiency, 50-99 microg/L; moderate deficiency, 20-49 microg/L; severe deficiency, < 20 microg/L); not more than 20% of the population should have a UIC below 50 microg/L. RESULTS: Median UIC for school children was 82 microg/L, and 14% of children had UICs below 50 microg/L. Thyroid volume reference values indicated a prevalence of goitre of zero. In girls, only four (3%) and one (1%) had thyroid volumes above the WHO/ICCIDD medians by age and body surface area (BSA), respectively (P < 0.001). In boys, three (2%) and one (1%) had thyroid volumes above WHO/ICCIDD medians by age and BSA, respectively (P < 0.001). CONCLUSION: Despite the median UIC being less than ideal, most children were not goitrous. This underscores the importance of using physiological outcome measures in areas where iodine deficiency is marginal before concluding the need for iodine supplementation based purely on median UIC. We call for a systematic national survey to determine iodine status using a combination of iodine deficiency indicators.

Adolescent↗
PubMed1999

Association between job characteristics and plasma fibrinogen in a normal working population: a cross sectional analysis in referents of the SHEEP Study. Stockholm Heart Epidemiology Program.

STUDY OBJECTIVE: To explore the association between job characteristics and plasma fibrinogen concentrations. DESIGN: Cross sectional design. SETTING: The Greater Stockholm area. SUBJECTS: A total of 1018 men and 490 women aged 45-70 who were randomly selected from the general population during 1992-1994. They were all employed and had no history of myocardial infarction. MAIN RESULTS: The self reported job characteristics were measured by a Swedish version of the Karasek demand-control questionnaire. For inferred scoring of job characteristics, psychosocial exposure categories (job control and psychological demands) were assigned by linking each subject's occupational history with a work organisation exposure matrix. Job strain was defined as the ratio between demands and control. In univariate analyses, expected linear trends were found in three of four tests of association between high plasma fibrinogen and low control (the self reported score for women and the inferred score for both sexes), in one of four tests of association between high plasma fibrinogen and high demands (the inferred score for women) and in two of four tests of association between high plasma fibrinogen and job strain (the inferred score for both sexes). Multiple logistic regression analyses showed that men in the inferred job strain group have an increased risk of falling into the increased plasma fibrinogen concentration group (above median level of the distribution) (odds ratio (OR) 1.2; 95% CI 1.0, 1.5) after adjustment for the variables that were associated with plasma fibrinogen in the univariate analyses. In women, low self reported control, high inferred demand, and inferred job strain were significantly associated with increased plasma fibrinogen concentration (OR 1.3; 95% CI 1.0, 1.8, OR 1.5; 95% CI 1.0, 2.2, OR 1.5; 95% CI 1.1, 2.2, respectively). CONCLUSIONS: These results indicate that adverse job characteristics may be related to plasma fibrinogen concentrations and this relation is more relevant in female workers. The clearest evidence for psychosocial effects on plasma fibrinogen seems to be with job control and the associations are clearer for the objective than for the self report variables.

Aged↗
PubMed1998

Gender differences in accessing cardiac surgery across England: a cross-sectional analysis of the health survey for England.

OBJECTIVE: To examine gender differences in access to cardiac surgery in a nationally representative sample. DESIGN: Nationwide cross sectional household based survey (Health Survey for England). SETTING: Private households in England around 1993 and 1994. SUBJECTS: 1708 subjects reporting a history of either doctor diagnosed angina or heart attack from a stratified random sample of 32 378 people aged 16 and above. OUTCOME MEASURE: The proportion reporting having had cardiac surgery or on a waiting list. RESULTS: 13.5% reported previous (n = 206) or pending (n = 25) cardiac surgery. Men were more likely than women to have had or to be waiting for cardiac surgery (19.1% of men versus 6.8% of women, chi2 54.7, P<0.001). This finding was consistent regardless of age group and across three regional areas. The unadjusted odds ratio for cardiac surgery for men versus women was 3.3 (95% Cl 2.3, 4.5, P<0.001) and was only slightly attenuated to 2.8 (95% CI 1.9, 4.0. P<0.001), after adjustment for other factors. The gender difference remained even when analysis was restricted to subjects reporting a previous heart attack, and after statistical adjustment for disease severity. CONCLUSION: Women are less likely than men to receive cardiac surgery across all age groups and regional areas. These results include private operations and adjust for individual behavioural data. Neither disease severity or co-morbidity explains these discrepancies. Further studies are required to determine why this inequality occurs and how it can be addressed.

Adolescent↗
PubMed1995

Longitudinal and cross-sectional analysis of raloxifene effects on tibiae from ovariectomized aged rats.

To extend and confirm previous data, we examined the effects of raloxifene on the proximal tibia of ovariectomized rats, aged 6 months, longitudinally and cross-sectionally by computed tomography (pQCT) and then compared the effects to those of orally dosed estrogen. Comparative analysis of phantoms and rat bones showed that the pQCT is precise and correlates with a Hologic QDR 1000W (DXA) with R = 0.999 but is capable of measuring significant differences between groups when the DXA cannot. This may reflect the ability of the pQCT to determine bone volume, mineral content (mg) and volumetric mineral density (mg/cm3), compared with two-dimensional analyses performed with DXA. Longitudinal analysis of the proximal tibia in vivo showed a significant 17% reduction in mineral density 31 days after ovariectomy. Examination of the images from ovariectomized rats showed a progressive increase in the cross-sectional area of the proximal tibiae, loss of trabecular bone, widening of marrow spaces and thinning of the cortical bone wall opposite the fibula. Regression analysis of the dose-dependent protective effects of raloxifene showed the half-maximal efficacy on tibiae mineral density to be ED50 = 0.4 mg/kg/day per os by pQCT and 0.2 mg/kg/day by DXA. By comparison, 17 alpha ethynyl estradiol showed dose-dependent effects with ED50 = 0.013 mg/kg/day per os by pQCT. Both raloxifene and ethynyl estradiol had beneficial effects on serum lipids, producing 50% reduction of cholesterol at 0.1 mg/kg/day raloxifene and 80% reduction with 0.01 mg/kg/day ethynyl estradiol. However, raloxifene up to 10 mg/kg/day had little effect on uterine weight, whereas 0.01 mg/kg/day ethynyl estradiol increased uterine wet weight by 300%.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed2005

Cross-sectional analysis of sexual function after prostate brachytherapy.

OBJECTIVES: To assess sexual function after prostate brachytherapy and compare outcomes in different age groups. METHODS: This cross-sectional study consisted of 96 sexually active patients (mean age 64 years) who underwent iodine-125 seed implantation between 1997 and 2003 to treat early-stage prostate cancer (Stage T1-T2). Patients completed a questionnaire adapted from the validated Rand 36-Item Health Survey and the University of California, Los Angeles, Prostate Cancer Index. RESULTS: The median follow-up was 2.5 years (range 3 months to 6.2 years). The mean value for sexual function was 54.8. The mean score for erectile function was 55.0, and the mean score for the ability to reach orgasm was 54.0. No significant relationship was found between sexual function and time since treatment (P = 0.9897). Pain on orgasm was reported after brachytherapy by 38 patients (40%) and hematospermia by 16 patients (17%). A negative correlation was observed between pain on orgasm and time since treatment (P = 0.021), but no significant relationship was found between hematospermia and time since treatment (P = 0.427). A significant difference in sexual function was observed between patients younger than 60 years and patients older than 60 years (66.3 +/- 7.0 versus 47.7 +/- 7.2; P = 0.002). CONCLUSIONS: A large variation in sexual potency is present after brachytherapy with no significant relationship to the time since treatment. Age is an indicator of sexual function after brachytherapy, with younger patients experiencing less sexual dysfunction than older patients. Other aspects of sexual function (pain on orgasm, hematospermia) are also significant side effects of brachytherapy and must be considered in the treatment decision for low-risk prostate cancer.

Aged↗
PubMed2004

Clustering of risk factors and social class in childhood and adulthood in British women's heart and health study: cross sectional analysis.

OBJECTIVE: To examine co-occurrence and clustering of risk factors used in the Framingham equation by social class in childhood and adult life. DESIGN: Cross sectional study. SETTING: 23 towns across England, Wales, and Scotland. PARTICIPANTS: 2936 women aged 60-79 years. MAIN OUTCOME MEASURES: Prevalence of risk factors (hypertension, obesity, smoking, left ventricular hypertrophy on electrocardiography, diabetes, and low concentration of high density cholesterol); ratios of observed to expected frequencies of clusters of risk factors. RESULTS: Risk factors were more common in women from manual social classes in either childhood or adult life, and the co-occurrence of three or four of these risk factors was greater among more disadvantaged groups. Within the four socioeconomic groups, these risk factors occurred together more than would be expected from their individual frequency distributions, indicating that they were clustered. The extent of this clustering was similar in all four social class groups. CONCLUSIONS: Clustering of risk factors included in the Framingham risk function occurs in all social class groups, but the lack of social patterning makes it unlikely that clustering is an explanation of socioeconomic inequalities in cardiovascular disease. As the proportion of women with co-occurrence of risk factors is greatest in those from manual social class in childhood, this measure of socioeconomic position might prove useful in risk prediction.

Aged↗
PubMedDate not supplied

Cross-sectional analysis of cognitive functioning across the life-span.

Performance on Piagetian logical concept tasks, standardized intellectual measures, and measures of memory ability, was assessed cross-sectionally. One-hundred-sixty individuals participated. Differential item difficulty patterns were noted on the Piagetian tasks. Curvilinear trends were evident for class inclusion, combinatorial reasoning, and conservation of surface area. Factorial analyses of variance revealed significant chronological age main effects for all tasks except transitivity of weight. Covariance analyses indicated that educational level is generally more closely related to logical concept performance than is chronological age. Dimensional analyses revealed separate factors for general intelligence, classification, relations, and conservation. The youngest and oldest age groups has similar factor patterns; these differed from those of the mature participants.

Adolescent↗
PubMed2000

Periorbital comedones and their relationship to pitch tar: a cross-sectional analysis and a review of the literature.

BACKGROUND: Comedones, often in a periorbital distribution, have been claimed to be associated with pitch tar. OBJECTIVE: This cross-sectional study compares the incidence of periorbital comedones between a group of individuals exposed to pitch tar and a control group. METHODS: The incidence of periorbital comedones was determined in workers (n = 55) at a tar distillation plant. A comparison group (n = 55) not exposed to pitch tar was also examined for the presence of facial comedones. The respective incidence rates were compared by using the Fisher exact test. RESULTS: Eighteen percent (10/55) of the study group and 4% (2/55) of the control group had periorbital comedones. The study group had a significantly greater incidence of periorbital comedones (P =.01). CONCLUSION: The incidence of periorbital comedones is significantly greater in individuals exposed to pitch tar. Further studies are needed to elucidate the potential relationship between pitch tar and periorbital comedones.

Acne Vulgaris↗
PubMed1991

[Evaluation of the Amor criteria for spondylarthropathies and European Spondylarthropathy Study Group (ESSG). A cross-sectional analysis of 2,228 patients].

Two sets of criteria have been proposed to discriminate spondylarthropathies (SA) from other rheumatic diseases. To evaluate their performance, we conducted a cross-sectional study in the patients observed during one week in 28 French Departments of Rheumatology by 91 staff-teaching physicians. The physicians had to apply these criteria to all their patients and had to classify them as definite SA, definite other rheumatic disease or possible SA. The analysis performed on the 2,088 patients with a definite diagnosis (124 SA and 1,964 controls) showed the following results: (table; see text) Of the 140 patients with possible SA, 37 fulfilled both sets of criteria, 22 the ESSG criteria alone and 12 the Amor criteria alone. These data suggest that a) the overall performance of these two sets of criteria is similar; b) this performance is better in the group of patients with a definite diagnosis; c) the patients without a definite diagnosis require a longer follow-up to assess the clinical relevance of these two sets of criteria.

Cross-Sectional Studies↗