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PubMed1997

Correlations among size-related traits affected by chromosome inversions in Drosophila buzzatii: the comparison within and across environments.

Genetic variation in correlations among size-related traits of head, thorax, and wings was examined in Drosophila buzzatii, by comparing the pattern of the Phenotypic Correlation Matrix (Rp) between inversion karyotypes of the second chromosome. No similarity in Rp was observed between some karyotypes in a natural population. The pattern of Rp in wild-reared heterokaryotypes, but not in homokaryotypes, was similar to the whole population represented by laboratory-reared flies. While phenotypic correlations in wild-reared flies were found to be larger than in laboratory-reared flies, similarity in the pattern of Rp was very high for one homokaryotype reared in both environments: the relatively homogeneous lab environment and the more variable field environment. While no such a similarity across environments was detected between different karyotypes, the pattern of Rp was similar for a same homokaryotype in different populations. Thus, the lack of karyotypic similarity in Rp is, at least partially, genetic. These results indicate that chromosomal inversions are factors affecting genetic correlations among traits known to be phenotypically correlated with adult fitness components in this species.

Animals↗

PubMed2006

Sub-nuclear localization of Rad51 in response to DNA damage.

The repair of DNA double-strand breaks involves the accumulation of key homologous recombination proteins in nuclear foci at the sites of repair. The organization of these foci in relation to non-chromatin nuclear structures is poorly understood. To address this question, we examined the distribution of several recombination proteins in subcellular fractions following treatment of HeLa cells with ionizing radiation and the crosslinking agent mitomycin C. The results showed association of Rad51, Rad54, BRCA1 and BRCA2, but not Rad51C, with the nuclear matrix fraction in response to double-strand breaks induction. The association of Rad51 with the nuclear matrix correlates with the formation of Rad51 nuclear foci as a result of DNA damage. Fractionation in situ confirmed that Rad51 foci remained firmly immobilized within the chromatin-depleted nuclei. Irs1SF cells that are unable to form Rad51 damage-induced nuclear foci did not show accumulation of Rad51 in the nuclear matrix. Similarly, no accumulation of Rad51 in the nuclear matrix could be observed after treatment of HeLa cells with the kinase inhibitor caffeine, which reduces formation of Rad51 foci. The results were compared to the distribution of the phosphorylated histone variant, gamma-H2AX. These data suggest a dynamic association and tethering of recombination proteins and surrounding chromatin regions to the nuclear matrix.

Animals↗

PubMed2002

[Cross sectional study of the relationship between physical fitness and life style, health-status in healthy aged males].

PURPOSE: The purpose of this study was to investigate the relationships between physical fitness and life style, as well as health-status in aged males living in a community. METHOD: A total of 304 males aged 60 to 89 years volunteered as subjects for this study. Eleven performance-test items were selected from four physical fitness domains of muscle, joint, neuromuscular and lung functions, with consideration given to the safety, reliability, and feasibility of the tests. To assess life style and health-status, a questionnaire consisting of 40 items was constructed. Principal component analysis was applled to the correlation matrix consisting of 11 physical fitness variables. Statistical techniques for Creamer's association coefficient and theory of quantification I were used to examine the relationships between life style, medical condition and fundamental physical fitness (FPF). RESULTS: Cramer's association coefficient was only significant for the variable of quantity consumed at dinner. Multiple correlation coefficient between FPF and age-grade, life style, and health-status were significant (P < 0.01). Partial correlation coefficients were high for the variables of aged-grade, sleeping hours, and receiving medical treatment. CONCLUSION: Fundamental physical fitness showed a decreasing trend with age. It was inferred that acquisltion of adequate sleeping hours and not taking medical treatment for injury of illness might be related to the decline of FPF level with aging in aged males.

Aged↗

PubMed2006

Pediatric Voice Handicap Index (pVHI): a new tool for evaluating pediatric dysphonia.

PURPOSE: The Voice Handicap Index (VHI) is widely used and accepted into adult clinical practice. The present study was initiated to adapt the VHI to the pediatric population and to validate it in the form of a parental proxy. METHODS: The initial modification of the adult VHI involved changing the language of the statements to reflect a parent's responses about their child and eliminating questions that would not relate to children. It was administered in conjunction with 10 open-ended questions regarding the impact of the child's voice quality on overall communication, development, education, social and family life. The pVHI was then modified in content and language, and the final 23-item parental proxy product was used for the validation process. The modified pVHI was administered to two groups of patients following IRB approval from Cincinnati Children's Hospital Medical Center. RESULTS: Normative data was obtained from 45 parents of healthy children. The group consisted of 21 males, age ranges 3-12 years old. The mean scores of the total pVHI and its subscales are: functional (F) 1.47, physical (P) 0.20, emotional (E) 0.18 and total (T) 1.84. The test group consisted of 33 guardians of children presenting for a voice evaluation pre- or post-laryngotracheal reconstruction. This group differed greatly from the control group on each subscale and total score. The mean scores of the airway group were as follows: F 13.94, P 15.48, E 12.15 and T 41.58. Test-retest reliability of the total pVHI score was measured using Pearson's correlation coefficient. The scores were 0.95, 0.77, 0.79 and 0.82, respectively. A correlation matrix for pVHI subscore and total score showed significance, with results similar to those reported for the original adult VHI. CONCLUSIONS: The aim of the present study was to modify the VHI to serve a similar role in the evaluation of the effects of dysphonia on the pediatric population. The statistical results reveal a high correlation between the VHI and the pVHI. The pVHI provides a high internal consistency and test-retest reliability. This tool will be utilized to follow a child's development following surgical, medical and behavioral interventions.

Adolescent↗

PubMed1995

Elevated luteinizing hormone on the day of human chorionic gonadotropin administration does not reduce cycle fecundity in a low-dose flare-up in vitro fertilization protocol.

OBJECTIVE: To determine if elevated LH at the time of hCG administration occurs and adversely affects success in a low-dose gonadotropin-releasing hormone analogue (GnRH-a) flare-up protocol in hMG-stimulated IVF cycles. DESIGN: Pearson correlation matrix analysis of hormonal, gamete, and clinical data derived from 203 consecutive IVF cycles was performed. All patients were treated with low-dose GnRH-a (250 micrograms SC leuprolide acetate) and hMG. In 203 consecutive IVF cases, serum was obtained on the day of hCG administration and assayed for E2, LH, and P. These data were correlated with peak E2, number of follicles, oocytes, embryos, and conceptions. Additionally, patients with elevated LH were compared with the nonelevated LH group. RESULTS: Twenty six women had LH > 35 mIU/mL (mean +/- SEM; 51.1 +/- 1.9) and five pregnancies (cycle fecundity 19.2% per retrieval). One hundred seventy-seven patients had LH < 35 mIU/mL (16.3 +/- 0.5) and 25 pregnancies (cycle fecundity 14.1%). There were no differences in the mean P (1.0 +/- 0.1 ng/mL, conversion factor to SI unit, 3.81) and E2 (1,672 +/- 144 pg/mL, conversion factor to SI unit, 3.671) of the former group compared with the P (1.1 +/- 0.07 ng/mL) and E2 (1,456 +/- 69 pg/mL) of the latter group. There was no correlation with the number of follicles, oocytes, embryos, pregnancies, E2, or P to LH concentration (rmax = 0.132). CONCLUSION: In a low-dose, GnRH-suppression, IVF induction protocol, elevated LH occurs in a small subset (13%) of women at the time of hCG administration. This event does not appear to alter cycle fecundity nor induce premature luteinization.

Chorionic Gonadotropin↗

PubMed2007

Biodistance analysis of the Moche sacrificial victims from Huaca de la Luna plaza 3C: Matrix method test of their origins.

The purpose of this study is to test two competing models regarding the origins of Early Intermediate Period (AD 200-750) sacrificial victims from the Huacas de Moche site using the matrix correlation method. The first model posits the sacrificial victims represent local elites who lost competitions in ritual battles with one another, while the other model suggests the victims were nonlocal warriors captured during warfare with nearby polities. We estimate biodistances for sacrificial victims from Huaca de la Luna Plaza 3C (AD 300-550) with eight previously reported samples from the north coast of Peru using both the mean measure of divergence (MMD) and Mahalanobis' distance (d2). Hypothetical matrices are developed based upon the assumptions of each of the two competing models regarding the origins of Moche sacrificial victims. When the MMD matrix is compared to the two hypothetical matrices using a partial-Mantel test (Smouse et al.: Syst Zool 35 (1986) 627-632), the ritual combat model (i.e. local origins) has a low and nonsignificant correlation (r = 0.134, P = 0.163), while the nonlocal origins model is highly correlated and significant (r = 0.688, P = 0.001). Comparisons of the d2 results and the two hypothetical matrices also produced low and nonsignificant correlation for the ritual combat model (r = 0.210, P = 0.212), while producing a higher and statistically significant result with the nonlocal origins model (r = 0.676, P = 0.002). We suggest that the Moche sacrificial victims represent nonlocal warriors captured in territorial combat with nearby competing polities.

Adult↗

PubMed1982

Naturally occurring enzyme activity variation in Drosophila melanogaster. II. Relationships among enzymes.

This report describes an investigation of the specificities of the genetic effects, caused by whole chromosome substitution, on the activities of 23 enzymes in Drosophila melanogaster. Two types of correlation estimates are examined, the product-moment correlation over the chromosome substitution line means and the corresponding correlation of line effects, which is a standardized covariance component estimate. The two types of correlations give very similar results. Although there is ample evidence for specific line effects on individual enzyme activities, there are extensive intercorrelations among many of the enzymes for both second- and third-chromosome substitution lines. The pattern of correlations with respect to the metabolic functions or other properties of the enzymes is difficult to visualize by inspection of the correlation matrix, so a multivariate graphical technique, the biplot (GABRIEL 1971), was employed to obtain a two-dimensional view of relationships among the enzyme activities. The second and third chromosome lines show similar patterns. Four of the five mitochondrial enzymes form one highly intercorrelated group whereas another highly intercorrelated group contains several cytosolic enzymes. Within the cytosolic group, particularly high correlations are observed between enzymes that have glucose 6-phosphate as a substrate or product and between enzymes that are NADP-dependent. Although the pattern of intercorrelations is not clearly explicable in terms of metabolic relationships among the enzymes, there is some tendency for enzymes that catalyze sequential reactions or share a substrate or product to have correlated activity levels.

Chromosome Mapping↗

PubMed1978

Epidemiology of poly-parasitism. II. Types of combinations, relative frequency and associations of multiple infections.

Frequency distributions, including all of the observed types of combinations of multiple infections with different helminths and protozoa are presented for sample villages of the African Savannah and of the trans-Andean part of Peru. Measurements of correlation between these infections based on properties of the multivariate, multinomial distribution are calculated to show age and sex patterns of association in different population samples. A correlation matrix for combined infections with Dipetalonema perstans, D. streptocerca and Loa loa, in villages in the rain forest of Zaire indicates that there is a statistically significant association between the two species of Dipetalonema and L. loa. There is also a strong association between the numbers of the microfilariae of D. perstans and D. streptocerca in multiply infected individuals. This correlation is strong only in the rain forest; it is insignificant in the other ecological zones of Bas-Zaire included in the study. The data suggest that there may be selective host factors that influence the extent, distribution and the types of multiple infections in a community.

Adolescent↗

PubMed1986

Development of the motor memory trace and control program.

A theoretical explanation of the development of the memory trace constrained to fit into a computer analog requires a coded reference "image" of the intended motor act, a tentative control program (memory trace) based on mobilizing and coordinating various pre-established motor-control subroutines, and an afferent neural description of the act as actually performed. The afferent information is non-consciously compared with the reference image, and the resulting discrepancy used to modify the control program so as to reproduce the reference image more exactly on the next attempt. The discrepancy consists of the sum of two types of differences, between image and program (present during learning) and the error difference between program and performance. The trial-by-trial discrepancies cumulate in the memory trace, so that during both learning and postlearning practice the error component results in a within-individual odd-even trial correlation. This constitutes a mechanism for a remoteness effect in the inter-trial correlation matrix generated in a group of individuals during post-learning as well as learning conditions. Fifty-one individuals performed 50 trials on a simple arm movement task; 35 of these (the learners) showed individual systematic improvement during the first 20 trials but no improvement during the last 24; 16 (the non-learners) failed to improve with practice. Separate correlational analyses (both within- and inter-individual) of the two groups resulted in a variety of patterns that were predicted a priori in the learners by the theory, as did the 49 learners of another sample of 51 who performed a more complicated arm movement task. Also, as predicted, the non-learners failed to produce organized correlation patterns.

Journal Article↗

PubMed1983

Emergency room admissions, meteorologic variables, and air pollutants: a path analysis.

Daily hospital emergency room admissions at hospitals located within 8 km of Los Angeles Basin monitoring stations at Long Beach, Lennox, Azusa, and Riverside, California, were examined for correlations with pollutant and meteorologic variables for 1974-1975. By conventional correlation and regression with lagged and temporospatial analysis, the authors could not distinguish effects of pollution by particulate sulfate from those due to meteorologic variables and oxidant. The authors use a variety of structural models and path analysis to estimate "direct" effects on emergency room admissions of maximum temperature, humidity, wind velocity, barometric pressure, carbon monoxide, sulfur dioxide, nitric oxide, high-volume suspended particulates, coefficient of haze, nitrogen dioxide, oxidant, and sulfate. Criteria for choice of models included plausibility of pairwise dependence relationships, magnitude of the correlations with emergency room admissions, and examination of the partial correlation matrix. Their results show that a variety of models gave similarly large path coefficients for a given location for the following variables: maximum temperature at each site; sulfate at Long Beach and Lennox but not at Riverside which nevertheless had the highest sulfate means; oxidant at Azusa which had the highest oxidant levels. At other locations, despite substantial and significantly elevated correlation coefficients, oxidant had a small or negative path coefficient. After considering other possible factors, the authors conclude that sulfate pollution at Lennox and Long Beach had an important and possibly causal association with demand for emergency room admissions. This demonstrates the usefulness of using a variety of structural models in the analysis of ecologic data.

Air Pollution↗

PubMed1997

Anhedonia and alexithymia: distinct or overlapping constructs.

The aim was to examine the relationship between alexithymia, anhedonia, and capacity for displeasure in a group of 133 healthy subjects using principal components analysis. A correlation matrix comprised of items from both the Communication and Identification scale of the 20-item Toronto Alexithymia Scale and the Physical Pleasure-Displeasure Scale yielded a four-factor solution (one Communication-Identification, two Pleasure, and one Displeasure factor) with no overlap of the significant factor loadings for the items from each scale. Moreover, there were no positive significant correlations between the Communication and Identification Scales and the Physical Anhedonia Scale. Our findings support the view that physical anhedonia is a construct distinct and separate from alexithymia.

Adolescent↗

PubMed1993

Diabetes mellitus and hypertension based on the family history and 2-h postprandial blood sugar in the Ann-Lo district (northern Taiwan).

From July 1988 to June 1990, we performed an epidemiological study on the prevalence of hypertension and diabetes mellitus (DM) in the Ann-Lo district, a suburban area of Northern Taiwan. One third of the population in the district was randomly sampled. A total of 9087 persons were screened with 67.4% participating. Following completion of the questionnaire blood pressure, 2 h postprandial blood sugar were determined. DM was defined when the blood sugar was over 200 mg/dl or the subject had a diabetic history. Hypertension was defined if the systolic blood pressure was over 160 mmHg or the diastolic blood pressure over 95 mmHg. Statistical comparisons were performed with a chi-square test, analysis of covariance, stepwise multiple regression and Pearson correlation matrix. In this study, the prevalence rate of DM was 2.6% and of hypertension was 6.4%. For those patients 40 years or older, the prevalence rate for DM was 8.0% and for hypertension was 19.7%. The prevalence of hypertension was 24.8% in overt diabetes and 5.2% in the normal subjects. Analysis of the data between risk factors of DM revealed that DM correlated with age, body mass index, hypertension, smoking, family history of DM and correlated negatively with education. Hypertension correlated with gender, alcohol intake and smoking, sugar level, age and body mass index. The prevalence rate of diabetes and hypertension were quite high in the district and this study pointed out the important risk factors for hypertension and DM in Taiwan.

Adolescent↗

PubMed1993

Effects of nitrendipine on blood pressure, renin-angiotensin-system and atrial natriuretic peptide in hypertensive type I diabetic patients.

In this study, the effects of a six week treatment with the calcium channel blocking agent nitrendipine were assessed in 20 hypertensive type I diabetic patients who received a single oral dose of 20 mg daily. Plasma concentrations of atrial natriuretic peptide (ANP), plasma renin activity (PRA) and active renin, aldosterone, glycosylated hemoglobin (HbA1) and fructosamines were determined at the beginning and the end of the study. Interactions of these endocrine parameters with blood pressure behaviour were analyzed by a correlation matrix. In response to the drug treatment, the blood pressure was significantly lowered from 158.0/97.2 to 145.7/88.2 mmHg. The plasma concentrations of ANP were also significantly reduced from 106.8 to 89.7 pg/ml. There were no changes in serum aldosterone, while PRA and active renin exhibited a significant increase following the six week treatment. HbA1 and fructosamines remained unaltered. There were no significant correlations for ANP and blood pressure values, as well as for ANP and PRA or aldosterone. We did find, however, a significant correlation of the ANP values with the difference of the systolic blood pressure levels pre- and post-treatment. These data fully confirm the blood pressure lowering properties of this calcium channel blocker and its possible interference with steroidogenesis, since the effects of increased PRA on aldosterone secretion were clearly blunted. The lowering of plasma ANP levels may represent a decreased ANP secretion due to calcium channel blockade or might also be due to the natriuretic effects of nitrendipine, thus allowing ANP levels to decline as a function of lessened sodium retention.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Construction and validation of a specific quality of life instrument for adolescents with spine deformities.

STUDY DESIGN: The development and construction of a specific instrument for measuring quality of life in adolescents with spine deformities was investigated. OBJECTIVES: To assess the validity and reliability of the Quality of Life Profile for Spine Deformities. SUMMARY OF BACKGROUND DATA: An 88-item questionnaire was self-administered to 174 patients ranging in age from 10 to 20 years with spine deformities. Items were rated on a five-point Likert scale. Higher scores means high level of impairment in quality of life. Age, gender, menarche or voice change, salient symptoms in the medical record, ordinary parameters on physical examination, and measurements on standard anteroposterior and lateral radiographs were recorded. The retest was done 10 days after the initial administration in a subsample of 35 patients. METHODS: The test-retest reliability was analyzed calculating the intraclass correlation coefficient. Internal consistency was measured with the Cronbach's alpha method. Factor analysis was used to obtain a reduced number of variables. Construct validity was assessed using the principal components model of factor analysis based on the correlation matrix and using the varimax computer algorithm for orthogonal rotation. Discriminant validity was assessed using the Kruskal-Wallis test. RESULTS: The Quality of Life Profile for Spine Deformities contained 21 items and five factors in conceptual terms labeled psychosocial functioning, sleep disturbances, back pain, body image, and back flexibility. The overall questionnaire score showed an internal consistency of 0.88 and a test-retest correlation of 0.91. Patients with structural curves showed significantly higher scores in all dimensions of the Quality of Life Profile for Spine Deformities except for the subscale of body image than patients with postural curves. When patients were grouped according to the symptom of back pain, those with backache had a significantly higher quality of life overalls score and scores in the dimensions of sleep disturbances and pain. Brace-treated patients showed statistically significant differences in the quality of life overall score and scores in the dimensions of psychosocial functioning and back flexibility. CONCLUSIONS: The instrument developed for measuring quality of life in patients with spine deformities during the period of bone growth has validity, internal consistency, and high test-retest reliability. The conceptualization of quality of life of the Quality of Life Profile for Spine Deformity includes psychosocial dimensions and pain and function.

Adolescent↗

PubMed2006

Clinical competence: general ability or case-specific?

BACKGROUND: Before the 1970s, research into the development of clinical competence was mainly focused on general problem-solving abilities. The scope of research changed when Elstein and colleagues discovered that individual ability to solve clinical problems varies considerably across cases. It was concluded that problem solving abilities are highly dependent on domain-specific knowledge rather than on general problem solving skills. Elstein called this phenomenon "case specificity." PURPOSE: The finding of content specificity will be contrasted with the existence of a general clinical problem solving ability, and the relationship between preclinical knowledge and a problem solving ability will be investigated. METHODS: A correlation matrix was calculated with clerkship final scores from 10 disciplines to examine the magnitude of the interrelations. A confirmatory factor analysis was applied to the corresponding covariances using structural equation modeling to investigate whether scores on finals shared any common variance across clerkships. Finally, two additional models were tested to examine the nature of the relationship between preclinical knowledge and problem solving. RESULTS: Low to moderate correlations across clerkship disciplines were found, supporting the original findings of content specificity. Further investigation showed that in addition to specific knowledge, a general, content-independent ability is needed to perform on these examinations. CONCLUSIONS: Clinical competence, as measured in this study, is based on a combination of specific preclinical knowledge and a problem-solving ability. Case specificity fits perfectly well in this interactional perspective on clinical problem solving but does not explain it. The phenomenon "case specificity" is therefore not solely a result of content knowledge, but of level of experience and level of case difficulty.

Clinical Clerkship↗

PubMed2006

Sorption-desorption tests to assess the risk derived from metal contamination in mineral and organic soils.

We obtained the sorption isotherms of Cd, Cu, Pb and Zn from seven soils with contrasting properties, including mineral and organic soils. The distribution coefficients (Kd) were determined from batch tests in a solution that simulated the soil solution cationic composition. The Kd values of the target metals varied greatly depending on soil type and initial metal concentration. Sorption isotherms were fitted to Freundlich and Langmuir models, and derived parameters were correlated to soil properties through the construction of a correlation matrix and application of Principal Component Analysis. The batch Kd showed a satisfactory agreement with the Kd obtained from field-contaminated soils. The sorption tests were complemented with the estimation of the reversibility of metal sorption by the application of an extraction test. The extraction yields, which did not relate to the initial metal concentration, depended on the metal-soil combination, and showed no correlation to batch Kd values. The risk derived from a contamination event was estimated through the quantification of a Retention Factor, defined as the ratio of the Kd versus the extraction yield. Results showed that this was an excellent index to highlight which metal and soil represent the most vulnerable scenarios after a contamination event.

Adsorption↗

PubMed2001

Sample size and power calculations with correlated binary data.

Correlated binary data are common in biomedical studies. Such data can be analyzed using Liang and Zeger's generalized estimating equations (GEE) approach. An attractive point of the GEE approach is that one can use a misspecified working correlation matrix, such as the working independence model (i.e., the identity matrix), and draw (asymptotically) valid statistical inference by using the so-called robust or sandwich variance estimator. In this article we derive some explicit formulas for sample size and power calculations under various common situations. The given formulas are based on using the robust variance estimator in GEE. We believe that these formulas will facilitate the practice in planning two-arm clinical trials with correlated binary outcome data.

Clinical Trials as Topic↗

PubMed2006

Impact of freeze-drying on ionization of sulfonephthalein probe molecules in trehalose-citrate systems.

"pH memory," i.e., correlation between pH of solution before freeze-drying and chemical reactivity in the freeze-dried state, has been reported in many systems. In this study, the "pH memory" is explored by comparing the extent of protonation of sulfonephthalein probe molecules, bromophenol blue, bromocresol green, and chlorophenol red, in aqueous solution in the pH range of 3.4-6.0 and in the resulting freeze-dried amorphous matrix (lyophile) containing trehalose and sodium citrate buffer. The protonation of the probe molecules was measured in the lyophiles by diffuse reflectance visible spectroscopy, and compared with that in the solution before drying. The protonation of the indicators in the amorphous matrix correlated with solution pH, that is, an increase in solution pH resulted in a progressive decrease in the indicator protonation in the corresponding lyophile. However, the protonation was consistently higher in the lyophile than in the corresponding solution. The Hammett acidity function of lyophiles was calculated based on the extent of protonation of the probe molecules. Protonation of the probe molecules and the Hammett acidity function depended not only on prelyophilization solution pH, but also on the residual water content and the presence of amorphous sugar in the lyophile.

Bromcresol Green↗