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PubMed2005

[Predictive markers of HIV and HCV infection and co-infection among inmates in a Spanish prison].

OBJECTIVE: To study the prevalence and factors associated with HIV and HCV infection among inmates of a Spanish prison. METHOD: A cross-sectional study was carried out in July 2001. We determined HCV (ELISA and RIBA-3) and HIV (ELISA and Western-blot) serology in the prison population. Study variables included age, sex, nationality and previous intravenous drug use (IDU). In IDU inmates we analyzed the age when intravenous drug use was initiated, years of consumption, age at first admission in prison and syringe sharing with other inmates. The subpopulations of Arab and Romani (gypsy) inmates were studied differentially. RESULTS: A total of 800 inmates (mean age 34.2 6 6.2 years) were evaluated; 74.3% were Spanish and 33.6% IDU. HCV serology was obtained in 730 inmates and HIV serology in 773 with the following seroprevalence results: HCV 38.2%, HIV 19.1% and HCV-HIV co-infection 18.8%. The variables associated with HCV or HIV infection in the univariate analysis were Spanish nationality, previous IDU and coinfection by the other virus. In the multivariate analysis, only coinfection and, particularly, previous IDU (HCV infection: adjusted ORp 104.8 [95% CI: 49.4-222.2]) (HIV infection adjusted ORp 45.1 [95% CI: 14.0-144.9]) maintained an association with the two infections. CONCLUSIONS: The prevalence of HIV and HCV infection and coinfection is high in Spanish prisons. Infection by either of these viruses and previous IDU were independently associated with both infections. The percentage of non-Spanish inmates with these infections is low.

Adult↗

PubMed2006

Inferring causal relationships among intermediate phenotypes and biomarkers: a case study of rheumatoid arthritis.

MOTIVATION: Genetic association analysis is based on statistical correlations which do not assign any cause-to-effect arrows between the two correlated variables. Normally, such assignment of cause and effect label is not necessary in genetic analysis since genes are always the cause and phenotypes are always the effect. However, among intermediate phenotypes and biomarkers, assigning cause and effect becomes meaningful, and causal inference can be useful. RESULTS: We show that causal inference is possible by an example in a study of rheumatoid arthritis. With the help of genotypic information, the shared epitope, the causal relationship between two biomarkers related to the disease, anti-cyclic citrullinated peptide (anti-CCP) and rheumatoid factor (RF) has been established. We emphasize the fact that third variable must be a genotype to be able to resolve potential ambiguities in causal inference. Two non-trivial conclusions have been reached by the causal inference: (1) anti-CCP is a cause of RF and (2) it is unlikely that a third confounding factor contributes to both anti-CCP and RF.

Arthritis, Rheumatoid↗

PubMed2002

Intraspecific molecular variation in the seaweed fly Coelopa frigida consistent with behavioural distinctness of British and Swedish populations.

The major aim of this study was to compare the intraspecific variation and genetic structure of the behaviourally distinct British and Swedish populations of the seaweed fly Coelopa frigida. C. frigida has been the subject of intense study into the basis of female choice. The behaviour of British females is consistent with a 'good genes' model, whereas that of the Swedish flies suggests a Fisher process, in which the difference between the former and the latter is defined by female choice increasing offspring viability in 'good genes' models. Through a study of variability in the mitochondrial cytochrome oxidase II gene from more than 600 flies, we show that there is clear differentiation at the molecular level between the two countries' populations, with an FST of > 75% and no shared haplotypes. Tajima's test reveals an excess of rare variants relative to expectation, which, if not the result of selective sweep, indicates either a population expansion or purifying selection against weakly deleterious variants. Within the two populations, substantial subpopulation differentiation is observed in the UK, where there is also evidence of isolation by distance. Swedish populations exhibit lower variability, and no evidence of isolation by distance, with the latter result possibly being related to the continuous distribution of suitable habitat. The pattern of intraspecific variation is explainable by a combination of contemporary and also historical factors. British and Swedish populations may have been descended from at least two separate founding populations during the recolonization of these areas following Pleistocene glaciations.

Alcohol Dehydrogenase↗

PubMed1994

Sources of variability of human plasma apolipoprotein A-IV levels and relationships with lipid metabolism.

Plasma apolipoprotein (apo) A-IV concentration was determined by immunoelectrophoretic assay (EIA) in 119 nuclear families. No significant effect of concomitants such as age, weight, height, body mass index, tobacco, and alcohol consumption was observed on apo A-IV levels in men and in boys. In women, contraceptive use and hormonal status affected apo A-IV levels. In girls, only age influenced the quantitative phenotype. After adjusting by specific concomitants significant correlations were observed between apo A-IV levels and triglycerides, apolipoprotein A-I and apo B levels, suggesting a role of apolipoprotein A-IV in the hepatic lipid metabolism. Intrafamilial correlations were estimated to investigate the plausibility of a common family factor. The results obtained in this study showed a significant correlation between family members with the exception of mother-daughter pairs. Using a variance components model, the contribution of genetic and environmental factors was then investigated. Different statistical models were used and two major hypotheses were statistically acceptable: the first hypothesis supports that shared and specific environmental factors explain 35 and 65%, respectively, of the total adjusted plasma apo A-IV variation. The fraction of apo A-IV variability attributable to genetic factors was null. The second hypothesis supports that the fraction of variability attributable to apo A-IV genetic variation is 67% and the common spouse environmental factors are responsible for 33% of the total variability and no specific environmental effect was found. Among the two hypotheses, taking account of the metabolism function, we support the first one without excluding gene-environment interactions which could mask the genetic influence.

Adult↗

PubMed2001

Clonal evolution in Waldenstrom macroglobulinemia highlights functional role of B-cell receptor.

The course of clonal evolution of 2 related clones in the blood of a patient with Waldenstrom macroglobulinemia (WM) indicates the functional importance for the expression of the B-cell receptor for the survival of these malignant cells. Protein and nucleotide sequencing of the paraproteins' variable regions revealed 2 predominant Vlambda and 2 VH sequences, each set comprised in the ratio 1:1.5. The 2 VH sequences and 2 Vlambda sequences shared the same VDJ and VJ junctional sequences, respectively, indicating that 2 malignant clones had evolved from a common ancestor. This is the first report on intraclonal heterogeneity in WM. Comparison of the Vlambda and VH sequences with the closest matching known germline genes showed that they contained approximately 10 somatic mutations each. The distribution and type of mutations demonstrate that mutations have continued to accumulate in the malignant clones and that selection has been operating to preserve immunoglobulin structure.

Base Sequence↗

PubMed2004

Inter- and intra-specific variation in the ontogeny of the hominoid facial skeleton: testing assumptions of ontogenetic variability.

In this paper we use geometric morphometric techniques to test two assumptions that are commonly made about variations in facial ontogeny: closely related species, or members of the same species, will share a common early post-natal ontogeny; and closely related species, or members of the same species, will share a common ontogenetic scaling trajectory. To test these assumptions we use four species of hominines: Homo sapiens, Gorilla gorilla, Pan troglodytes and Pan paniscus. The first assumption is falsified, both inter- and intra-specifically, using discriminant analysis with crossvalidation of subadults prior to the onset of the eruption of the permanent dentition. The second assumption only holds true for inter-specific comparisons of ontogenetic scaling trajectories, while assumptions of variation in intra-specific scaling trajectories are falsified with these data.

Adolescent↗

PubMed2002

Genetic variability in the insulin signalling pathway may contribute to the risk of late onset Alzheimer's disease.

OBJECTIVE: To test the hypothesis that polymorphic variation in insulin signalling genes may underlie the shared risk of dysfunctional insulin signalling and late onset Alzheimer's disease (AD). The p85alpha subunit of phosphatidyl inositol 3 kinase (PIK3R1) and the regulatory subunit 3 of protein phosphatase 1 (PPP1R3) were selected as candidate genes because both encode key proteins involved in insulin signalling and because polymorphisms in these genes have been previously implicated in insulin resistance or type II diabetes. METHODS: Analysis of the Met326Ile PIK3R1 and the Asp905Tyr PPP1R3 polymorphisms in 202 patients with late onset AD and 160 or 170 age matched normal subjects. RESULTS: Logistic regression analysis using the recessive genetic model showed significant differences in genotype and allelic frequencies between the AD group and normal controls (genotypes: odds ratio (OR) 2.09, 95% confidence interval (CI) 1.17 to 3.74, p = 0.01; alleles: OR 1.99, 95% CI 1.17 to 3.40, p = 0.01) for the Met326Ile PIK3R1 polymorphism that were female specific. Additionally, in the dominant genetic model a marginally significant association in genotype frequencies between the Asp905Tyr PPP1R3 polymorphism and AD was observed (genotypes: OR 1.85, 95% CI 1.03 to 3.30, p = 0.04; alleles: OR 1.68, 95% CI 0.98 to 2.88, p = 0.06). Both polymorphisms were tested for their interactions with sex and the presence of the apolipoprotein E epsilon 4 allele. CONCLUSIONS: The results support the hypothesis for a common genetic aetiology predisposing to insulin resistance and AD.

Age Factors↗

PubMed2002

Target selection for reaching and saccades share a similar behavioral reference frame in the macaque.

The selection of one of two visual stimuli as a target for a motor action may depend on external as well as internal variables. We examined whether the preference to select a leftward or rightward target depends on the action that is performed (eye or arm movement) and to what extent the choice is influenced by the target location. Two targets were presented at the same distance to the left and right of a fixation position and the stimulus onset asynchrony (SOA) was adjusted until both targets were selected equally often. This balanced SOA time is then a quantitative measure of selection preference. In two macaque monkeys tested, we found the balanced SOA shifted to the left side for left-arm movements and to the right side for right-arm movements. Target selection strongly depended on the horizontal target location. By varying eye, head, and trunk position, we found this dependency embedded in a head-centered behavioral reference frame for saccade targets and, somewhat counter-intuitively, for reach targets as well. Target selection for reach movements was influenced by the eye position, while saccade target selection was unaffected by the arm position. These findings suggest that the neural processes underlying target selection for a reaching movement are to a large extent independent of the coordinate frame ultimately used to make the limb movement, but are instead closely linked to the coordinate frame used to plan a saccade to that target. This similarity may be indicative of a common spatial framework for hand-eye coordination.

Animals↗

PubMed1996

Marginal zone B-cell lymphomas of different sites share similar cytogenetic and morphologic features.

Clinical, histologic, cytogenetic, and molecular genetic data of 31 patients with extranodal, nodal, and splenic marginal zone B-cell lymphoma (MZBCL) are presented. Despite these variable clinical manifestations, a similar spectrum of morphologic features as well as distinctive immunophenotypic findings were noted. In all cases, a monotypic B-cell proliferation consistently negative for CD5, CD10, and CD23 was found expanding the marginal zone of the B follicle with and without colonization of the follicle centers. Clonal chromosomal abnormalities were detected in 23 of the 31 patients. Recurrent aberrations included whole or partial trisomy 3 (18 cases), trisomy 18 (9 cases), and structural rearrangements of chromosome 1 with breakpoints in 1q21 (9 cases) or 1p34 (6 cases), all of which were seen in extranodal, nodal, as well as splenic MZBCL. Abnormalities of the additional chromosome 3, such as +del(3)(p13),+i(3)(q10), or structural changes involving the distal part of the long arm, were evident in 9 of the 18 cases. All recurrent abnormalities were found in MZBCL more frequently than in other histologic entities of B-cell non-Hodgkin's lymphoma (B-NHL). None of the known lymphoma-associated chromosomal changes or rearrangements of the BCL1, BCL2, BCL3, BCL6, and CMYC genes were detected. We conclude that MZBCL represent a distinct entity of B-NHL with characteristic morphologic and immunophenotypic features and particular chromosomal abnormalities, and that a close histogenetic relationship between extranodal, nodal, and splenic MZBCL is likely, although the clinical presentation may vary.

Adult↗

PubMed2004

Meager genetic variability of the human malaria agent Plasmodium vivax.

Malaria is a major human parasitic disease caused by four species of Plasmodium protozoa. Plasmodium vivax, the most widespread, affects millions of people across Africa, Asia, the Middle East, and Central and South America. We have studied the genetic variability of 13 microsatellite loci in 108 samples from 8 localities in Asia, Africa, South America, and New Guinea. Only one locus is polymorphic; nine are completely monomorphic, and the remaining three are monomorphic in all but one or two populations, which have a rare second allele. In contrast, Plasmodium falciparum displays extensive microsatellite polymorphism within and among populations. We further have analyzed, in 96 samples from the same 8 localities, 8 tandem repeats (TRs) located on a 100-kb contiguous chromosome segment described as highly polymorphic. Each locus exhibits 2-10 alleles in the whole sample but little intrapopulation polymorphism (1-5 alleles with a prevailing allele in most cases). Eight microsatellite loci monomorphic in P. vivax are polymorphic in three of five Plasmodium species related to P. vivax (two to seven individuals sampled). Plasmodium simium, a parasite of New World monkeys, is genetically indistinguishable from P. vivax. At 13 microsatellite loci and at 7 of the 8 TRs, both species share the same (or most common) allele. Scarce microsatellite polymorphism may reflect selective sweeps or population bottlenecks in recent evolutionary history of P. vivax; the differential variability of the TRs may reflect selective processes acting on particular regions of the genome. We infer that the world expansion of P. vivax as a human parasite occurred recently, perhaps <10,000 years ago.

Animals↗

PubMed2001

Analysis of treatment failures and survival of patients with fallopian tube carcinoma: a cooperation task force (CTF) study.

OBJECTIVE: The objective of this retrospective multicenter study was to assess the pattern of failures and survival of patients with primary carcinoma of the fallopian tube. METHODS: The hospital records of 88 patients with primary carcinoma of the fallopian tube were reviewed. Surgery was the initial therapy for all patients. Tumor stage was I in 21 (23.9%), II in 21 (23.9%), III in 43 (48.8%), and IV in 3 (3.4%) patients. Postoperative treatment was given without well-defined protocols. The median follow-up of survivors was 55 months (range, 7-182). RESULTS: Of the 21 patients with stage I disease, 10 had no postoperative treatment and 11 had platinum-based chemotherapy. Five (23.8%) patients recurred after a median of 29 months (range, 8-93) from initial surgery. Of the 21 patients with stage II disease, 2 had no postoperative treatment, 2 underwent external pelvic irradiation, 16 received platinum-based chemotherapy, and 1 patient had oral melphalan. Eight (38.1%) patients recurred after a median of 25.5 months (range, 7-57). Of the 46 patients with stage III-IV disease, 1 patient refused chemotherapy and died after 19 months and 45 patients received platinum-based chemotherapy. A clinical complete response was obtained in 29 (64.4%) patients and a partial response in 8 (17.8%). A second-look laparotomy was performed in 14 of the 29 clinically complete responders: 12 patients were found to be in pathological complete response and 2 had persistent disease. Six (50.0%) of the former recurred after a median of 22 months (range, 13-101) from initial surgery. The two patients with persistent disease developed tumor progression after 15 and 11 months, respectively. Fifteen clinically complete responders did not undergo second-look, and 7 (46.7%) of them had a recurrence after a median of 18 months (range, 9-41). For the whole series, 5-year survival was 57%. By log-rank test, survival was related to FIGO stage (III-IV vs I-II, P = 0.0001), tumor grade (G3 vs G1 + G2, P = 0.0038), and patient age (>58.5 years vs <58.5 years, P = 0.0069), but not to histological type. The Cox model showed that FIGO stage (P = 0.0018) and patient age (P = 0.0290) were independent prognostic variables for survival. Among the patients with stage III-IV disease, 5-year survival was 55% for the patients who had residual tumor <1 cm compared with 21% for those who had larger residuum (P = 0.0169). CONCLUSIONS: Primary carcinoma of the fallopian tube shares several biological and clinical features with ovarian carcinoma. However, when compared with the latter, fallopian tube carcinoma more often tends to recur in retroperitoneal nodes and distant sites. Stage, patient age, and, among patients with advanced disease, residual tumor after initial surgery represent important prognostic variables for survival.

Adult↗

PubMed2006

Crystal structure of neurotropism-associated variable surface protein 1 (Vsp1) of Borrelia turicatae.

Vsp surface lipoproteins are serotype-defining antigens of relapsing fever spirochetes that undergo multiphasic antigenic variation to allow bacterial persistence in spite of an immune response. Two isogenic serotypes of Borrelia turicatae strain Oz1 differ in their Vsp sequences and in disease manifestations in infected mice: Vsp1 is associated with the selection of a neurological niche, while Vsp2 is associated with blood and skin infection. We report here crystal structures of the Vsp1 dimer at 2.7 and 2.2 A. The structures confirm that relapsing fever Vsp proteins share a common helical fold with OspCs of Lyme disease-causing Borrelia. The fold features an inner stem formed by highly conserved N and C termini and an outer "dome" formed by the variable central residues. Both Vsp1 and OspC structures possess small water-filled cavities, or pockets, that are lined largely by variable residues and are thus highly variable in shape. These features appear to signify tolerance of the Vsp-OspC fold for imperfect packing of residues at its antigenic surface. Structural comparison of Vsp1 with a homology model for Vsp2 suggests that observed differences in disease manifestation may arise in part from distinct differences in electrostatic surface properties; additional predicted positively charged surface patches on Vsp2 compared to Vsp1 may be sufficient to explain the relative propensity of Vsp2 to bind to acidic glycosaminoglycans.

Antigens, Bacterial↗

PubMed2006

Association of a traditional vs shared meal decision-making and preparation style with eating behavior of Hispanic women in San Diego County.

OBJECTIVE: To examine the influence of meal decision-making and preparation on Hispanic women's dietary practices. DESIGN: One-on-one structured interviews were conducted, assessing meal decision-making and preparation practices, barriers, and behavioral strategies to eating low-fat and high-fiber diets, fat and fiber intake, demographic, and other psychosocial factors. SUBJECTS/SETTING: The study population included 357 Hispanic women living in the southern or central regions of San Diego County. Participants were recruited via random-digit dialing to a tailored nutrition communication intervention. MAIN OUTCOME MEASURE: Household decision-making style (alone vs with family) by household activity (decides meals, prepares meals, and decides snacks). STATISTICAL ANALYSES PERFORMED: Multiple logistic regressions were used to evaluate associations between the predictors and dependent variable. All models included adjustments for potential confounders, such as marital status, education, employment, age, and acculturation. RESULTS: A positive statistical association between Hispanic women's acculturation level and shared decision-making style was found. Also, Hispanic women in shared decision-making households faced greater psychosocial barriers to healthful eating and reported less healthful eating compared with Hispanic women in traditional households. Women in shared decision-making households were more likely to eat at fast-food restaurants, less likely to engage in behavioral strategies promoting fiber consumption, eat more saturated fat, and encounter more barriers to reduce dietary fat as compared with Hispanic women in traditional households. Acculturation did not attenuate differences in psychosocial and dietary practices between shared decision-making and traditional households. CONCLUSIONS: Study findings suggest intervention efforts should focus on different aspects of healthful eating among Hispanic women in shared-decision, compared with traditional, households.

Acculturation↗

PubMed1997

Estimating familial and genetic contributions to variability in human testicular function: a pilot twin study.

The biological basis for the remarkably wide variation in sperm output between and within men remains unclear. Although some contributing factors have been identified, the familial and genetic contributions to variation in human sperm output have been little studied, although such sources of variation are known to be significant in experimental animals. In order to identify such familial and genetic factors in a classical twin study design, we recruited monozygotic and dizygotic twins aiming to study the degree of resemblance between genetically identical and non-identical twins in sperm output, testis size and testicular endocrine function. From an approach to 160 twin pairs on the Australian Twin Register database, eventually 17 pairs of male twins (11 monozygotic and six dizygotic) participated in this study. Sperm concentration and output, right testis size and SHBG all exhibited a strong familial effect but a genetic component could not be confirmed. Total and free testosterone exhibited a genetic component. Although identifying for the first time a clear familial component to normal human spermatogenesis, this study had insufficient power to determine whether there was a genetic component, nor could its design distinguish between genetic or shared (early) environmental determinants for these familial effects. Implications for future twin studies of human testicular function including stronger recruitment strategies, multi-centre studies and surrogate variables for human spermatogenesis are suggested.

Adult↗

PubMedDate not supplied

High density lipoprotein apoprotein variability in a biracial population.

High density lipoprotein (HDL) cholesterol is a sensitive index for coronary disease in affluent societies. We have measured plasma apoprotein A-I levels (the major HDL protein) in randomly selected groups of urban and rural Fijian Melanesians and Indians. Despite higher prevalence rates of coronary disease and diabetes mellitus in Indians, Indian men and women had significantly higher A-I levels than Melanesian men and women. Multivariate analysis was carried out separately in all men and women of both races and also in younger men and women (less than 45 years old) to determine the predictive values of seven variables that might influence A-I levels. These variables accounted for about 16% of the A-I variation and of this more than one-half was due to ethnic origin. The remainder was largely due to three environmental factors: urbanization, alcohol consumption, and physical activity. Men and women aged 20 to 44 years had significantly higher A-I levels in the town than in villages; alcohol drinkers had significantly higher A-I levels than nondrinkers, and in women physical inactivity resulted in significantly lower A-I levels. Age, smoking cigarettes, and body mass index did not contribute to the differences in A-I levels between the two races, despite less smoking and overweight among Indians. This study of a biracial population, that shares a similar environment but differs in cultural habits, has demonstrated the operation of genetic and environmental factors that explain a minor proportion of apoprotein A-I variability.

Adult↗

PubMed2002

Interspecies conservation and differential expression of mouse desmoglein gene family.

Epithelial cell adhesion is mediated by intercellular junctions, called desmosomes. Desmogleins (Dsg; Dsg1, Dsg2 and Dsg3) are calcium-dependent transmembrane adhesion components of the desmosomes. While Dsg1 and Dsg3 are mainly restricted to stratified squamous epithelia, Dsg2 is expressed in essentially all desmosome-containing epithelia. In the epidermis, Dsg2 and Dsg3 are expressed in the basal keratinocytes while Dsg1 is expressed throughout the upper differentiating cell layers. To date, in mouse, only Dsg3 has been characterized by molecular cloning. In this study, we have cloned and characterized the mouse Dsg1 and Dsg2 genes. The full-length mouse Dsg1 cDNA (5.5 kb) contains an open reading frame (ORF) of 3171 bp encoding a precursor protein of 1057 amino acids. The Dsg2 cDNA (6.3 kb) has an ORF of 3366 bp coding for a precursor protein of 1122 amino acids. Mouse Dsg2 protein shares 76% identity with human DSG2 but only 26% and 33% identity with mouse Dsg1 and Dsg3, respectively. Analysis of intron/exon organization of the desmoglein genes revealed significant conservation. However, the mRNA expression patterns of these desmogleins during mouse embryonic development and in various adult tissues are variable. While Dsg2 and Dsg3 are expressed in all developmental stages, Dsg1 expression is delayed until day 15 of mouse embryos. In adult mouse tissues, Dsg2 is widely expressed while the expression of Dsg1 and Dsg3 is restricted to select tissues. In summary, while desmogleins share high homology at both the gene and protein level, their expression is spatially and temporally regulated, potentially contributing to their significant role in cell-cell adhesion during development.

Amino Acid Sequence↗

PubMed2026

Differences between mitotically old and young endometrial tumors.

Human tumors likely differ in their mitotic ages, reflecting how many divisions elapse between the final tumor progenitor cell and surgical removal. We used a rapidly fluctuating CpG (fCpG) methylation clock to infer relative endometrial adenocarcinomas (EAC) mitotic ages. Experimentally, young tumors initiated from single cells show low-diversity, high-variance fCpG distributions with trimodal peaks near 0%, 50%, and 100%, reflecting inherited progenitor methylation states. fCpG methylation becomes polymorphic with divisions, and older tumors exhibit higher diversity, lower variance, and unimodal distributions centered around 50%. Mitotic ages varied across EAC samples. Synchronous hyperplasia and invasive regions generally shared similar ages, and primary-metastatic EAC pairs showed both synchronous and stepwise progression. The Cancer Genome Atlas (TCGA) EACs also showed variable mitotic ages: younger tumors were enriched for proliferation pathways, whereas older tumors showed more immune infiltration, immune-pathway activation, and evidence of T-cell exhaustion. These results show that human tumors can be ranked by mitotic age and suggest that the growth of older cancers is restrained by immune surveillance. © 2026 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Humans↗

PubMed1997

Are subjects' perceptual asymmetries on auditory and visual language tasks correlated?: a meta-analysis.

A number of studies have investigated the correlation between subjects' perceptual asymmetries on auditory and visual language tasks. With few exceptions, these studies have found low, nonsignificant correlations between the two types of perceptual asymmetries. However, variations in subjects' perceptual asymmetries on these tasks reflect not only individual differences in language lateralization but also several extraneous variables (e.g., random errors, individual differences in left-right attentional biases). Thus, low correlations between the two types of asymmetries may reflect "masking" by these extraneous variables rather than a "true" cross-modal dissociation. Consistent with this view, a meta-analysis of prior studies revealed a small, but significant correlation between the two types of asymmetries for left-handers. The correlation was nonsignificant for right-handers, presumably reflecting stronger attenuation caused by limited variability in language lateralization in this group. Possible factors mediating significant correlations between the two types of perceptual asymmetries include certain language processes shared by the two types of tasks, cross-modal consistency in individual differences in lateralization of certain modality-specific language processes, and cross-modal consistency in individual differences in left-right attentional biases.

Attention↗