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PubMed2004

Amino acid patterns within short consensus repeats define conserved duplicons shared by genes of the RCA complex.

Complement control proteins (CCPs) contain repeated protein domains, short consensus repeats (SCRs), which must be relevant to diverse functions such as complement activation, coagulation, viral binding, fetal implantation, and self-nonself recognition. Although SCRs share some discontinuous and imperfect motifs, there are many variable positions and indels making classification in subfamilies extremely difficult. Using domain-by-domain phylogenetic analysis, we have found that most domains can be classified into only 11 subfamilies, designated a, b, c, d, e, f, g, h, i, j, or k and identified by critical residues. Each particular CCP is characterized by the order of representatives of the subfamilies. Human complement receptor 1 (CR1) has ajefbkd repeated four times and followed by ch. The classification crosses CCPs and indicates that a particular CCP is a function of the mix of SCRs. The aje set is a feature of several CCPs including human CR1 and DAF and murine Crry and appears to be associated with the success or failure of implantation inter alia. This approach facilitates genomic analysis of available sequences and suggests a framework for the evolution of CCPs. Units of duplication range from single SCRs, to septamers such as efbkdaj, to extensive segments such as MCP-CR1L. Imperfections of duplication with subsequent deletion have contributed to diversification.

Amino Acid Motifs↗
PubMed1997

Dap (Defective aleurone pigmentation) mutations affect maize aleurone development.

Dap (Defective aleurone pigmentation) is the designation for mutations in maize that give rise to a characteristic dappled endosperm phenotype, consisting of patches of purple tissue, of variable size and shape, on a yellow background. Features shared by all Dap mutants are: dominant expression when they are maternally derived, lack of expression or transmission when they originate from pollen, failure to recover homozygous Dap genotypes, reduced frequency of Dap seeds in the progeny of outcrosses of Dap/+ females, association of the dappled phenotype with reduction in seed size. The mutants so far tested, six in all, can be grouped into two classes, one including male-transmissible (MT) isolates not expressed in the endosperm if their contribution is paternal, and a second class of isolates (NMT) that are permanently lost following paternal transmission. We suggest that the NMT mutations are on a chromosome that carries an intercalary deletion. Assuming linkage between the mutant and the deletion, selection against the deficient chromosome during male gametogenesis would account for the failure to recover Dap seeds in the progeny of Dap/+ male parents. We have obtained genetic evidence supporting this hypothesis. This interpretation, however, does not apply to MT alleles. For these, other mechanisms, such as imprinting and/or dosage effects may be proposed. The mutable pattern in the endosperm to which all Dap mutants give rise is an intriguing phenotype which remains to be clarified. An unexpected finding is that aleuronic and subaleuronic cells corresponding to the colourless areas are abnormal in shape and anthocyanin biosynthesis is blocked in these cells. This finding calls for further investigation in light of a possible connection between flavonoid precursors and cell shape.

Anthocyanins↗
PubMed2005

Identification of a locus for nongoitrous congenital hypothyroidism on chromosome 15q25.3-26.1.

Permanent congenital hypothyroidism is the most prevalent inborn endocrine disorder, and principally due to developmental defects leading to absent, ectopic or hypoplastic thyroid gland. Although commonly regarded as sporadic disease, nonsyndromic thyroid hypoplasia has, in rare cases, been attributed to inherited defects in PAX8 and the TSHR gene. The shared clinical picture caused by these defects is a variable degree of thyrotropin resistance (RTSH [MIM 275200]), accompanied in its severe form by thyroid gland hypoplasia. We recently identified six extended kindreds with autosomal dominant RTSH, only one of which was linked to a mutation in the PAX8 candidate gene. Genome wide scans conducted in two of the remaining five families revealed independently significant linkage to chromosome 15q25.3-26.1, with maximum multipoint LOD scores of 8.51 and 4.31. Linkage to this novel locus was replicated (P<0.01) in each of the three remaining kindreds. Fine mapping of key recombinants in the largest family localized the causative gene within a 3 cM/2.9 Mb interval. Thus, we report the first locus for congenital nongoitrous hypothyroidism identified by a genome wide screening approach.

Chromosomes, Human, Pair 15↗
PubMed2007

Multivariate Cholesky models of human female fertility patterns in the NLSY.

Substantial evidence now exists that variables measuring or correlated with human fertility outcomes have a heritable component. In this study, we define a series of age-sequenced fertility variables, and fit multivariate models to account for underlying shared genetic and environmental sources of variance. We make predictions based on a theory developed by Udry [(1996) Biosocial models of low-fertility societies. In: Casterline, JB, Lee RD, Foote KA (eds) Fertility in the United States: new patterns, new theories. The Population Council, New York] suggesting that biological/genetic motivations can be more easily realized and measured in settings in which fertility choices are available. Udry's theory, along with principles from molecular genetics and certain tenets of life history theory, allow us to make specific predictions about biometrical patterns across age. Consistent with predictions, our results suggest that there are different sources of genetic influence on fertility variance at early compared to later ages, but that there is only one source of shared environmental influence that occurs at early ages. These patterns are suggestive of the types of gene-gene and gene-environment interactions for which we must account to better understand individual differences in fertility outcomes.

Analysis of Variance↗
PubMed1993

A small chromosome of Leishmania (Viannia) braziliensis contains multicopy sequences which are complex specific.

Orthogonal Field Alternating Gel Electrophoresis (OFAGE) has been used to show a band of approximately 260 kb which is stained intensely with ethidium bromide in Leishmania (V.) braziliensis stock M2903. This small chromosome (sc-2903), as well as a 50 kb and a 200 kb chromosome seen in L. (L.) mexicana and L. (L.) amazonensis, respectively, are stably maintained and linear. When used as a hybridisation probe, sc-2903 showed homology to large chromosomal DNA bands and to a multiplicity of genomic fragments in all braziliensis stocks tested, indicating either different sequences, different copy numbers or both but no hybridisation to mexicana stocks. It is possible that these sequences are present in all members of the braziliensis complex and are not related to LD1 or any other previously published small chromosome sequences. However, at least one clone isolated from a sc-2903 library recognised genomic DNA of stocks belonging to the braziliensis, mexicana and donovani complexes. Our results suggest that the clone carries sequence(s) that are repeated and shared between stocks of different complexes but with a variable genomic distribution.

Animals↗
PubMed1996

The mosquito ultraspiracle homologue, a partner of ecdysteroid receptor heterodimer: cloning and characterization of isoforms expressed during vitellogenesis.

We report the cloning and characterization of two isoforms of the Ultraspiracle homologue (AaUSP) from the mosquito, Aedes aegypti. The 2.33-kb AaUSPa cDNA has an open reading frame (ORF) of 484 amino acids encoding a polypeptide of 54 kDa, whereas the 2.14-kb AaUSPb ORF of 459 amino acids encodes a 51.3 kDa polypeptide. The AaUSPa and AaUSPb proteins differ only in the N-terminal portion of the variable A/B domain. The AaUSP DNA-binding domain shares 92% and 97% identities with the respective domains of the Drosophila (DmUSP) and Bombyx (BmUSP) Ultraspiracles. However, the AaUSP ligand-binding domain is only 57% and 52% identical to those of DmUSP and BmUSP, respectively. In spite of the relatively low level of sequence conservation, electrophoretic mobility shift assay (EMSA) and hormone-binding assay clearly demonstrated that the products of the AaUSPa and AaUSPb cDNAs are functional heterodimeric partners of the mosquito ecdysteroid receptor. In vitellogenic tissues, each of the two AaUSP isoforms is expressed differently: the AaUSPa is predominant in the fat body and the AaUSPb in the ovary. The kinetics of ovarian AaUSP mRNA coincide with those of the ecdysteroid receptor, being elevated during the previtellogenic period and shortly after the onset of vitellogenesis. In contrast, the level of the AaUSP in the fat body remains relatively constant throughout most of the vitellogenic cycle.

Aedes↗
PubMed2007

Chlamydial interferon gamma immune evasion influences infection tropism.

Chlamydia trachomatis is a human pathogen and Chlamydia muridarum is a mouse pathogen but paradoxically, they share near genomic synteny. The majority of strain-variable genes are located primarily in a hyper-variable region termed the plasticity zone. Tryptophan synthase and cytotoxin are plasticity zone genes unique to the human and murine strains, respectively. Tryptophan synthase is a virulence factor that differentiates C. trachomatis strains into genital and ocular disease pathotypes, whereas cytotoxin(s) is a virulence factor linked to murine infection tropism. Divergence in these loci is strongly correlated with host-specific interferon gamma effector activities, suggesting that these virulence genes have co-evolved with their respective hosts as a primary mechanism to evade innate immunity. These findings have important implications for chlamydial animal modeling studies.

Animals↗
PubMed1993

Ca channel kinetics during the spontaneous heart beat in embryonic chick ventricle cells.

The ability of Ca ions to inhibit Ca channels presents one of the most intriguing problems in membrane biophysics. Because of this negative feedback, Ca channels can regulate the current that flows through them. The kinetics of the channels depend on voltage, and, because the voltage controls the current, a strong interaction exists between voltage dependence and Ca dependence. In addition to this interaction, the proximity of pores and the local concentration of ions also determine how effectively the Ca ions influence channel kinetics. The present article proposes a model that incorporates voltage-dependent kinetics, current-dependent kinetics, and channel clustering. We have based the model on previous voltage-clamp data and on Ca and Ba action currents measured during the action potential in beating heart cells. In general we observe that great variability exists in channel kinetics from patch to patch: Ba or Ca currents have low or high amplitudes and slow or fast kinetics during essentially the same voltage regime, either applied step-protocols or spontaneous cell action potentials. To explain this variability, we have postulated that Ca channels interact through shared ions. The model we propose expands on our previous model for Ba currents. We use the same voltage-dependent rate constants for the Ca currents that we did for the Ba currents. However, we vary the current-dependent rate constants according to the species of the conducting ion. The model reproduces the main features of our data, and we use it to predict Ca channel kinetics under physiological conditions. Preliminary reports of this work have appeared (DeFelice et al., 1991, Biophys. J. 59:551a; Risso et al., 1992, Biophys. J. 61:248a).

Action Potentials↗
PubMed2003

Mutual influences of general practitioners in partnerships.

The aim of this study was to find out whether or not general practitioners (GPs) within the same partnership show more similarities in attitudes and behaviour than GPs in different partnerships, and what the causes of these similarities might be. Knowledge of the causes of patterns of similarities within medical teams contributes to understanding medical practice variation, which is crucial in developing effective health care policies. Data were used from the Dutch National Survey of General Practice ('87/'88), consisting of a stratified sample of 161 Dutch GPs, who served 335,000 patients in total. To find out whether GPs in the same partnership are indeed more similar than GPs randomly chosen from different partnerships, we constructed two kinds of pairs: all possible pairs of GPs working in the same partnership (actual pairs), and randomly constructed pairs of GPs who are not working in the same partnership (random pairs). For each pair difference scores were computed for a variety of attitudes and behaviour. Difference scores for actual and random pairs were analysed using multi-level analysis. Most differences in attitudes and behaviour were smaller for actual pairs than for random pairs. Furthermore, in the majority of the cases differences were no longer statistically significant after explanatory variables indicating selection, gradual adaptation and rapid adaptation through shared circumstances were taken into account. It was found that Dutch GPs working in the same partnership showed more resemblance in attitudes and behaviour than GPs not working in the same partnership. Most indications point towards circumstances, and to a lesser extent towards adaptation, as an explanation of similarities within partnerships. The implication of this study is that medical practice variations are not merely individual differences in preferred practice style, but are patterned by social processes in partnerships and local circumstances.

Attitude of Health Personnel↗
PubMed2005

Studies of an enneanuclear manganese single-molecule magnet.

The reaction of [Mn(3)O(O(2)CMe)(6)(py)(3)] with the tripodal ligand H(3)thme (1,1,1-tris(hydroxymethyl)ethane) affords the enneanuclear complex [Mn(9)O(7)(O(2)CCH(3))(11)(thme)(py)(3)(H(2)O)(2)] 1.1MeCN.1Et(2)O. The metallic skeleton of complex 1 comprises a series of 10 edge-sharing triangles that describes part of an idealized icosahedron. Variable temperature direct current (dc) magnetic susceptibility data collected in the 1.8-300 K temperature range and in fields up to 5.5 T were fitted to give a spin ground state of S = (17)/(2) with an axial zero-field splitting parameter D = -0.29 cm(-)(1). Ac susceptibility studies indicate frequency-dependent out-of-phase signals below 4 K and an effective barrier for the relaxation of the magnetization of U(eff) = 27 K. Magnetic measurements of single crystals of 1 at low temperature show time- and temperature-dependent hysteresis loops which contain steps at regular intervals of field. Inelastic neutron scattering (INS) studies on complex 1 confirm the S = (17)/(2) ground state and analysis of the INS transitions within the zero-field split ground state leads to determination of the axial anisotropy, D = -0.249 cm(-)(1), and the crystal field parameter, B(4)(0) = 7(4) x 10(-)(6) cm(-)(1). Frequency domain magnetic resonance spectroscopy (FDMRS) determined the same parameters as D = -0.247 cm(-)(1) and B(4)(0) = 4.6 x 10(-)(6) cm(-)(1). DFT calculations are fully consistent with the experimental findings of two Mn(II) and four Mn(III) ions "spin up" and three Mn(IV) ions "spin down" resulting in the S = (17)/(2) spin ground state of the molecule, with D = -0.23 cm(-)(1) and U = 26.2 K.

Journal Article↗
PubMed2006

Self-disclosure, depression, anxiety, and suicidal behavior in adolescent psychiatric inpatients.

The objectives of this paper were to examine the personality variable of self-disclosure, or the tendency to share feelings with others, and its relationship to depression, anxiety, and suicidal behavior in adolescent psychiatric inpatients. Of the 87 adolescents who were assessed, 53 had made a suicide attempt and 34 had never shown any suicidal behavior during their lifetime. There was a significant relationship between suicidality and low levels of self-disclosure, which appears to be mediated by anxiety and depression. This sharing difficulty was most significantly marked between the adolescent and his/her family and seemed to be mediated by feelings of depression and anxiety.

Adolescent↗
PubMed2003

Risk of hearing impairment in pediatric liver transplant recipients: a single center study.

As survival rates following liver transplantation have increased, health care providers must assess the impact of transplantation on dimensions other than traditional medical measures. Hearing impairment may adversely impact social, emotional, cognitive, academic, and speech and language development. We hypothesized that children who undergo liver transplantation are at risk for hearing impairment due to exposure to ototoxic drugs. We conducted a review of 74 children who had undergone liver transplantation between December 1996 and September 2000 at Cincinnati Children's Hospital Medical Center. Hearing was assessed at discharge by an audiologist using age and developmentally appropriate techniques. The principal outcome measure was sensorineural hearing impairment. Independent variables were age at transplantation, United Network for Organ Sharing (UNOS) status at transplantation, primary diagnosis, post-transplant length of hospital stay, days of treatment with aminoglycosides, and days of treatment with loop diuretics. Eleven of 74 children (15%) had sensorineural hearing loss, of whom four had severe to profound hearing loss. Multivariate analyses showed that the adjusted relative risk for hearing loss in patients with hepatoblastoma was 66 and that there was a 5% increase risk for hearing loss for each additional day of hospitalization. Age at transplantation, UNOS status, and days of treatment with loop diuretics or aminoglycosides did not achieve significance in the model. Sensorineural hearing impairment occurs in a subset of pediatric patients following liver transplantation. Patients with hepatoblastoma or those who experience prolonged hospitalization after transplantation are at increased risk. Our observations are of particular importance for pediatric liver transplant recipients since the median age at transplantation is 12-18 months, a critical period for language acquisition.

Biliary Atresia↗
PubMed1986

Adjusting for confounding with statistical software packages.

Much computer use in support of clinical research involves the execution of standard statistical packages. Prenatal risks, such as maternal substance use, may be related to outcomes, such as lowered birthweight for gestational age, using multiple regression. In standard stepwise multiple regression, variance shared by two risks is attributed to the first variable entered in the equation, potentially underestimating the effect size of subsequently entered variables. A novel solution to this problem, adapted from the epidemiologic technique of calculating attributable risk, is applied in the multivariate setting and produces more appropriate estimates of the effect sizes of independent risks. An example of this method, using a standard statistical package, is presented.

Alcohol Drinking↗
PubMed1992

Complete sequence of a cDNA clone specifying sandbar shark immunoglobulin light chain: gene organization and implications for the evolution of light chains.

A full-length cDNA clone specifying sandbar shark (Carcharhinus plumbeus) immunoglobulin light chain has been isolated and sequenced. By alignment with human lambda chains, the leader, framework, complementarity-determining, joining, and constant regions are clearly identified in the shark light chain. Approximately 40-50% identity is shared between the human and shark sequences in the variable and constant regions. We have performed sequence comparisons of the individual segments and constructed phylogenetic trees for the variable region. These studies identify the shark protein as a lambda chain. In addition, the sandbar shark light chain is only distantly related to that of horned shark (Heterodontus francisci) [Shamblott, M. J. & Litman, G. W. (1989) Proc. Natl. Acad. Sci. USA 86, 4684-4688], demonstrating that the long evolutionary time of divergence among shark species has led to the generation of substantial differences in sequence. The positions of the variable, joining, and constant gene segments in 14 genomic clones have been mapped. The segments are linked in individual clusters (variable, joining, constant) occupying 3-7 kilobases. Cluster arrangement can be grouped into two patterns based upon spacing between the genes in the individual clones. This arrangement is fundamentally different from that observed in higher vertebrates.

Amino Acid Sequence↗
PubMed1993

Specific activation and targeting of cytotoxic lymphocytes through chimeric single chains consisting of antibody-binding domains and the gamma or zeta subunits of the immunoglobulin and T-cell receptors.

The generation of tumor-specific lymphocytes and their use in adoptive immunotherapy is limited to a few malignancies because most spontaneous tumors are very weak or not at all immunogenic. On the other hand, many anti-tumor antibodies have been described which bind tumor-associated antigens shared among tumors of the same histology. Combining the variable regions (Fv) of an antibody with the constant regions of the T-cell receptor (TCR) chains results in chimeric genes endowing T lymphocytes with antibody-type specificity, potentially allowing cellular adoptive immunotherapy against types of tumors not previously possible. To generalize and extend this approach to additional lymphocyte-activating molecules, we designed and constructed chimeric genes composed of a single-chain Fv domain (scFv) of an antibody linked with gamma or zeta chains, the common signal-transducing subunits of the immunoglobulin receptor and the TCR. Such chimeric genes containing the Fv region of an anti-trinitophenyl antibody could be expressed as functional surface receptors in a cytolytic T-cell hybridoma. They triggered interleukin 2 secretion upon encountering antigen and mediated non-major-histocompatibility-complex-restricted hapten-specific target cell lysis. Such chimeric receptors can be exploited to provide T cells and other effector lymphocytes, such as natural killer cells, with antibody-type recognition directly coupled to cellular activation.

Animals↗
PubMed2001

Residential status and HIV risk behaviors among Puerto Rican drug injectors in New York and Puerto Rico.

This article investigates the association between residential status and human immunodeficiency virus (HIV) risk behaviors among island and New York Puerto Rican injection drug users (IDUs). We assigned 561 subjects from New York City and 312 from Puerto Rico to five residential status categories: living in parent's home, living in own home, living in other's home, living in temporary housing (hotel, single-room occupancy [SRO] hotels), and homeless (living in streets/shelters). Dependent variables included injection- and sex-related risk behaviors (sharing syringes, sharing other injection paraphernalia, shooting gallery use, and having paid sex). Chi square, t tests, and multivariate logistic analysis tests were performed separately by site. About one-quarter of the sample in each site was homeless. Island Puerto Ricans were more likely to live with their parents (44% vs. 12%, p < .001), and more New York IDUs lived in their own home (30% vs. 14%, p < .001). In New York, gallery use and paid sex were associated with living in other's home, living in parent's home, and being homeless. Sharing paraphernalia was related to living in other's home, living in temporary housing, and being homeless. In Puerto Rico, having paid sex was associated with homelessness. High-risk behaviors were more likely among homeless IDUs in both sites. Programs to provide housing and target outreach and other prevention programs for homeless IDUs would be helpful in reducing HIV risk.

Adult↗
PubMed2002

Is a polymorphism of the apolipoprotein E gene associated with preeclampsia?

OBJECTIVE: Apolipoprotein E (apo E) is pivotal in lipid metabolism. In women with preeclampsia, an atherogenic state is observed. We hypothesized that a particular genotype of apo E may be associated with preeclampsia. METHODS: Genomic DNA was extracted from 55 normotensive and 49 preeclamptic women (defined according to the American College of Obstetricians and Gynecologists criteria). DNA was amplified by PCR and digested simultaneously by AflIII and HaeII giving profiles identifying all the possible genotypes of apo E. RESULTS: The most common isoform apo E3 was found both for normotensive and preeclamptic women (76% and 85%, respectively). The frequency of apo E2 and E4, which are more atherogenic, was not higher in the preeclamptic population. CONCLUSION: We were unable to demonstrate that the "atherogenic state" of preeclampsia is associated with a particular genotype of apo E. Familial studies show that shared genetic and environmental factors are involved in lipid variability. However, owing to the diversity of factors contributing to the development of preeclampsia (fetal and paternal genotypes), these data do not allow to rule-out a possible contribution of maternal apo E to preeclampsia.

Adult↗