A high-density SNP linkage scan with 142 combined subtype ADHD sib pairs identifies linkage regions on chromosomes 9 and 16

As part of the International Multi-centre ADHD Genetics project we completed an affected sibling pair study of 142 narrowly defined Diagnostic and Statistical Manual of Mental Disorders, fourth edition combined type attention deficit hyperactivity disorder (ADHD) proband-sibling pairs. No linkage was observed on the most established ADHD-linked genomic regions of 5p and 17p. We found suggestive linkage signals on chromosomes 9 and 16, respectively, with the highest multipoint nonparametric linkage signal on chromosome 16q23 at 99 cM (log of the odds, LOD=3.1) overlapping data published from the previous UCLA (University of California, Los Angeles) (LOD>1, approximately 95 cM) and Dutch (LOD>1, approximately 100 cM) studies. The second highest peak in this study was on chromosome 9q22 at 90 cM (LOD=2.13); both the previous UCLA and German studies also found some evidence of linkage at almost the same location (UCLA LOD=1.45 at 93 cM; German LOD=0.68 at 100 cM). The overlap of these two main peaks with previous findings suggests that loci linked to ADHD may lie within these regions. Meta-analysis or reanalysis of the raw data of all the available ADHD linkage scan data may help to clarify whether these represent true linked loci.

Celecoxib inhibits tumor growth and angiogenesis in an orthotopic implantation tumor model of human colon cancer

AIM

To examine the effect of celecoxib on tumor growth and angiogenesis in an orthotopic implantation tumor model of colon cancer.

METHODS

Human colorectal adenocarcinoma HT-29 cells were implanted subcutaneously in nude mice. Four groups of animals received different doses of celecoxib after tumor implantation. After 42 days, all animals were evaluated for changes in body weight, the volume and weight of colorectal tumors, and tumor growth inhibition. The content of prostaglandin E(2) (PGE(2)) in the tumor tissue homogenate was estimated by radioimmunoassay (RIA). Cyclooxygenase-2 (COX-2) and CD34 expression in tumor tissue was assessed by immunohistochemistry, and the microvessel density (MVD) of tumor tissue was determined. Apoptosis of the tumor cells was detected by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL). The expression of vascular endothelial growth factor (VEGF) mRNA and matrix metalloproteinase-2 (MMP-2) mRNA extracted from the tumor tissue was analyzed by reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTS

There was no statistically significant change in the animals' body weight between the treatment groups. However, with increasing doses of celecoxib, the volume and weight of the tumor decreased. The rates of tumor growth inhibition for the L (low), M (medium) and H (high) groups were 25.30%, 38.80%, and 76.92%, respectively, which were significant compared to the C (control) group. There were significant differences in COX-2 expression in the tumor tissue between all groups, except between the L and M groups. Celecoxib exposure also reduced PGE2 levels in the tumor tissue homogenates. The level of PGE(2) correlated to the weight of tumor (r=0.8814, P < 0.05) and to COX-2 expression (r=0.8249, Puse < 0.05). Compared to the control group, the tumor cells from celecoxib-treated mice had a significantly higher apoptotic index. Celecoxib also decreased CD34(+) expression in tumors from treated mice. There were significant differences in the MVD between all groups except between groups H and M. Celecoxib significantly reduced the expression of VEGF and MMP-2 mRNA in the group H but not in L and M groups. The MVD in tumor tissue was closely related to the PGE2 levels, as well as the expression of VEGF and MMP-2 mRNA (r = 0.9006, r = 0.8573 and r = 0.6427, respectively; P < 0.05).

CONCLUSIONS

By inhibiting COX-2, PGE(2) synthesis, and VEGF and MMP-2 mRNA expression in tumor tissue, celecoxib enhances tumor cell apoptosis, thereby inhibiting the growth and angiogenesis of orthotopically implanted tumors in a mouse model of human colorectal cancer.

Inhibition of airway eosinophilia and pulmonary pathology in a mouse model of allergic asthma by the live vaccine strain of Francisella tularensis

BACKGROUND

It has been suggested that exposure to certain microbes and their products, particularly during neonatal and early childhood periods, may shift the immune response towards a T-helper cell (Th) 1 phenotype and thereby prevent the development of and/or alleviate the clinical symptoms of allergic airway diseases.

OBJECTIVE

We evaluated the ability of the live vaccine strain (LVS) of Francisella tularensis to suppress airway eosinophilia and pulmonary pathology in a murine model of allergic airway disease.

METHODS

C57BL/6 mice were sensitized by intraperitoneal injection of ovalbumin (OVA) on days 1 and 14, and challenged intranasally (i.n.) with OVA on day 21 or thereafter. Some sensitized mice were i.n. treated with live LVS or its cell-free sonicate extract (CFSE) before i.n. OVA challenge. Bronchoalveolar lavage fluid, regional lymph node cells, lung tissues and serum samples were collected 3-7 days after the i.n. challenge.

RESULTS

Intranasal and, to a lesser degree, intradermal immunization of OVA-sensitized mice with LVS suppressed the development of airway eosinophilia and associated pulmonary pathology induced by i.n. OVA challenge. Moreover, CFSE prepared from LVS showed a similar inhibitory effect whereas neither LPS nor DNA purified from F. tularensis LVS had such an effect. The inhibition was associated with the reduction in mRNA expression and protein levels of Th2 cytokines IL-5 and IL-13 in the lungs and the enhanced production of OVA-induced IFN-gamma by local draining lymph node cells, but not with the serum levels of OVA-specific IgG1 or IgE.

CONCLUSION

F. tularensis LVS is capable of suppressing allergic airway inflammation probably through a Th1-mediated suppression of an ongoing Th2 response mechanism, and raises the possibility of exploring LVS and its components as potential therapeutic modalities for human allergic asthma.

Baseline Sensitivity of Ascochyta rabiei to Azoxystrobin, Pyraclostrobin, and Boscalid

Ascochyta rabiei, causal agent of Ascochyta blight on chickpea (Cicer arietinum), can cause severe yield loss in the United States. Growers rely on applications of fungicides with site-specific modes of action such as the quinone outside inhibiting (QoI) fungicides azoxystrobin and pyraclostrobin, and the carboximide fungicide boscalid, to manage disease. In all, 51 isolates collected prior to QoI fungicide registration and 71 isolates collected prior to boscalid registration in the United States were tested in an in vitro assay to determine the effective fungicide concentration at which 50% of conidial germination was inhibited (EC₅₀) for each isolate-fungicide combination. The effect of salicylhydroxamic acid (SHAM) on conidia of A. rabiei in the presence and absence of azoxystrobin also was assessed to determine whether the fungus is capable of using alternative respiration. Five of nine A. rabiei isolates tested had significantly higher (P ≤ 0.05) EC₅₀ values when SHAM was not included in media amended with azoxystrobin, indicating that A. rabiei has the potential to use alternative respiration to overcome fungicide toxicity in vitro. EC₅₀ values of azoxystrobin and pyraclostrobin ranged from 0.0182 to 0.0338 μg/ml and from 0.0012 to 0.0033 μg/ml, with mean values of 0.0272 and 0.0023 μg/ml, respectively. EC₅₀ values of boscalid ranged from 0.0177 to 0.4960 μg/ml, with a mean of 0.1903 μg/ml. Establishment of these baselines is the first step in developing a monitoring program to determine whether shifts in sensitivity to these fungicides are occurring in the A. rabiei pathogen population.

Co-transmission of conduct problems with attention-deficit/hyperactivity disorder: familial evidence for a distinct disorder

Common disorders of childhood and adolescence are attention-deficit/hyperactivity disorder (ADHD), oppositional defiant disorder (ODD) and conduct disorder (CD). For one to two cases in three diagnosed with ADHD the disorders may be comorbid. However, whether comorbid conduct problems (CP) represents a separate disorder or a severe form of ADHD remains controversial. We investigated familial recurrence patterns of the pure or comorbid condition in families with at least two children and one definite case of DSM-IV ADHDct (combined-type) as part of the International Multicentre ADHD Genetics Study (IMAGE). Using case diagnoses (PACS, parental account) and symptom ratings (Parent/Teacher Strengths and Difficulties [SDQ], and Conners Questionnaires [CPTRS]) we studied 1009 cases (241 with ADHDonly and 768 with ADHD + CP), and their 1591 siblings. CP was defined as > or =4 on the SDQ conduct-subscale, and T > or = 65, on Conners' oppositional-score. Multinomial logistic regression was used to ascertain recurrence risks of the pure and comorbid conditions in the siblings as predicted by the status of the cases. There was a higher relative risk to develop ADHD + CP for siblings of cases with ADHD + CP (RRR = 4.9; 95%CI: 2.59-9.41); p < 0.001) than with ADHDonly. Rates of ADHDonly in siblings of cases with ADHD + CP were lower but significant (RRR = 2.9; 95%CI: 1.6-5.3, p < 0.001). Children with ADHD + CP scored higher on the Conners ADHDct symptom-scales than those with ADHDonly. Our finding that ADHD + CP can represent a familial distinct subtype possibly with a distinct genetic etiology is consistent with a high risk for cosegregation. Further, ADHD + CP can be a more severe disorder than ADHDonly with symptoms stable from childhood through adolescence. The findings provide partial support for the ICD-10 distinction between hyperkinetic disorder (F90.0) and hyperkinetic conduct disorder (F90.1).

Differential dopamine receptor D4 allele association with ADHD dependent of proband season of birth

Season of birth (SOB) has been associated with attention deficit hyperactivity disorder (ADHD) in two existing studies. One further study reported an interaction between SOB and genotypes of the dopamine D4 receptor (DRD4) gene. It is important that these findings are further investigated to confirm or refute the findings. In this study, we investigated the SOB association with ADHD in four independent samples collected for molecular genetic studies of ADHD and found a small but significant increase in summer births compared to a large population control dataset. We also observed a significant association with the 7-repeat allele of the DRD4 gene variable number tandem repeat polymorphism in exon three with probands born in the winter season, with no significant differential transmission of this allele between summer and winter seasons. Preferential transmission of the 2-repeat allele to ADHD probands occurred in those who were born during the summer season, but did not surpass significance for association, even though the difference in transmission between the two seasons was nominally significant. However, following adjustment for multiple testing of alleles none of the SOB effects remained significant. We conclude that the DRD4 7-repeat allele is associated with ADHD but there is no association or interaction with SOB for increased risk for ADHD. Our findings suggest that we can refute a possible effect of SOB for ADHD.

Immunodominance hierarchies and gender bias in direct T(CD8)-cell alloreactivity

Allogeneic solid organ transplantation often occurs across multiple donor-recipient HLA mismatches with consequent risk of allograft rejection. However, there is growing evidence that not all HLA mismatches are equivalent in their stimulation of allogeneic T cells making it important to determine which of these might be more significant as predictors of allograft rejection. To this end, we used defined antigen-presenting cell (APC) transfectants expressing single MHC-I allotypes as target cells that could discriminate the relative contribution of individual mismatched MHC-I allotypes to direct T-cell alloreactivity. We demonstrate remarkably reproducible patterns of immunodominance in reactivity across mismatched MHC-I allotypes. These patterns are HLA context-dependent, partly reflecting alloantigenic competition in responder cell responses. In strong alloresponses, we also observed an increased percentage of alloreactive T(CD8) cells in female responders, regardless of the stimulator gender, highlighting HLA-independent factors in the potency of the alloresponse. This approach provides a potential measure of specific alloreactive T cells that could be used in clinical practice for selection of donors, assessment of posttransplant outcomes, modulation of immunosuppression and detection of rejection episodes.

Effects of superoxide dismutase and catalase derivates on intracerebral hemorrhage-induced brain injury in rats

The use of exogenous superoxide dismutase (SOD) and catalase (CAT) has been previously evaluated against various reactive oxygen species-mediated brain injuries, especially those associated with ischemia/ reperfusion. In this study, we investigated effects of these enzymatic antioxidants on intracerebral hemorrhage (ICH)-induced brain injury. A total of 65 male Sprague-Dawley rats (300-380 g) were divided into a sham group, an untreated ICH group, 3 groups of ICH rats treated with lecithinized SOD (PC-SOD) at doses of 0.1, 0.3, and 1 mg/kg, and a group treated with polyethylene glycol conjugated CAT (PEG-CAT) at a dose of 10,000 U/kg. An additional group of ICH rats received a combination of PC-SOD (1 mg/kg) and PEG-CAT (10,000 U/kg). ICH was induced by collagenase injection. All drugs were administered intravenously immediately after ICH induction. Brain injury was evaluated by scoring neurological function and measuring brain edema at 24 h after ICH induction. Our results demonstrated that ICH caused significant neurological deficit associated with remarkable brain edema. Treatment with PC-SOD, PEG-CAT, or PC-SOD in combination with PEG-CAT did not reduce brain edema or neurological deficit after ICH. We conclude that intravenously administered PC-SOD and/or PEG-CAT do not reduce brain injury in the collagenase-induced ICH rat model.

Significant alterations of biodistribution and immune responses in Balb/c mice administered with adenovirus targeted to CD40(+) cells

CD40 ligation has been shown to promote antigen-presenting functions of dendritic cells, which express CD40 receptor. Here we reported significantly altered biodistribution and immune responses with the use of CD40-targeted adenovirus. Compared with unmodified adenovirus 5, the CD40-targeted adenovirus following intravenous administration (i.v.) resulted in increased transgene expressions in the lung and thymus, which normally do not take up significant amounts of adenovirus. Intradermal injection saw modified adenovirus being mainly processed in local draining lymph nodes and skin. Following intranasal administration (i.n.), neither unmodified nor targeted viruses were found to be in the liver or spleen, which predominantly took up the virus following i.v. administration. However, inadvertent infection of the brain was found with unmodified adenoviruses, with the second highest gene expression among 14 tissues examined. Importantly, such undesirable effects were largely ablated with the use of targeted vector. Moreover, the targeted adenovirus elicited more sustained antigen-specific cellular immune responses (up to 17-fold) at later time points (30 days post boosting), but also significantly hampered humoral responses irrespective of administration routes. Additional data suggest the skewed immune responses induced by the targeted adenoviruses were not due to the identity of the transgene but more likely a combination of overall transgene load and CD40 stimulation.

Chitosan-polycarbophil complexes in swellable matrix systems for controlled drug release

A prerequisite for progress in the design of novel drug delivery systems is the development of excipients that are capable of fulfilling multifunctional roles such as controlling the release of the drug according to the therapeutic needs. Although several polymers have been utilised in the development of specialised drug delivery systems, their scope in dosage form design can be enlarged through combining different polymers. When a polymer is cross-linked or complexed with an oppositely charged polyelectrolyte, a three-dimensional network is formed in which the drug can be incorporated to control its release. The swelling properties and release kinetics of two model drugs with different water solubilities (i.e. diltiazem and ibuprofen) from monolithic matrix tablets consisting of an interpolyelectrolyte complex between chitosan and polycarbophil are reported. Matrix tablets consisting of this polymeric complex without drug or excipients exhibited extremely high swelling properties that are completely reversible upon drying. The drug release from matrix systems with different formulations depended on the concentration of the chitosan-polycarbophil interpolyelectrolyte complex and approached zero order release kinetics for both model drugs. The chitosan-polycarbophil interpolyelectrolyte complex has demonstrated a high potential as an excipient for the production of swellable matrix systems with controlled drug release properties.