Genome-wide association study of lifetime cannabis use based on a large meta-analytic sample of 32 330 subjects from the International Cannabis Consortium

Cannabis is the most widely produced and consumed illicit psychoactive substance worldwide. Occasional cannabis use can progress to frequent use, abuse and dependence with all known adverse physical, psychological and social consequences. Individual differences in cannabis initiation are heritable (40-48%). The International Cannabis Consortium was established with the aim to identify genetic risk variants of cannabis use. We conducted a meta-analysis of genome-wide association data of 13 cohorts (N=32 330) and four replication samples (N=5627). In addition, we performed a gene-based test of association, estimated single-nucleotide polymorphism (SNP)-based heritability and explored the genetic correlation between lifetime cannabis use and cigarette use using LD score regression. No individual SNPs reached genome-wide significance. Nonetheless, gene-based tests identified four genes significantly associated with lifetime cannabis use: NCAM1, CADM2, SCOC and KCNT2. Previous studies reported associations of NCAM1 with cigarette smoking and other substance use, and those of CADM2 with body mass index, processing speed and autism disorders, which are phenotypes previously reported to be associated with cannabis use. Furthermore, we showed that, combined across the genome, all common SNPs explained 13-20% (P<0.001) of the liability of lifetime cannabis use. Finally, there was a strong genetic correlation (rg=0.83; P=1.85 × 10(-8)) between lifetime cannabis use and lifetime cigarette smoking implying that the SNP effect sizes of the two traits are highly correlated. This is the largest meta-analysis of cannabis GWA studies to date, revealing important new insights into the genetic pathways of lifetime cannabis use. Future functional studies should explore the impact of the identified genes on the biological mechanisms of cannabis use.

Gender differences in the association of overweight and asthma morbidity among urban adolescents with asthma

Asthma and obesity disproportionately affect US African-American youth. Among youth with asthma, obesity has been associated with poor control. The impact of gender on this association is unclear. We examined these relationships in a sample of urban, African-American adolescents with asthma. Questionnaires were used to identify high school students with asthma, and to examine the association of body mass index (BMI) to asthma morbidity, by gender. Of 5967 students completing questionnaires, 599 (10%) met criteria for asthma and 507 had data sufficient for inclusion in further analyses (46% male, mean age = 15.1 yr). Univariately, BMI > 85th percentile was significantly related only to reported emergency department visits (ED) and school days missed for any reason, Odds Ratio (95%Confidence Interval) = 1.7(1.1-2.7), p = 0.01 and 1.8(1.1-3.0), p = 0.01, respectively. A significant gender-BMI interaction (p < 0.05) was observed in multivariate models for ED visits, hospitalizations and school days missed for asthma. In gender-specific models, adjusted Risk Ratios for BMI > 85th and ED visits, hospitalizations, and school days missed because of asthma were 1.7(0.9-3.2), 6.6(3.1-14.6) and 3.6(1.8-7.2) in males. These associations were not observed in females. Gender modifies the association between BMI and asthma-related morbidity among adolescents with asthma. Results have implications for clinical management as well as future research.

Elevated expression of DNA ligase I in human cancers

PURPOSE

Human DNA ligase I plays an essential role in DNA replication, recombination, and repair by catalyzing the formation of phosphodiester bonds between adjacent 5'-phosphoryl and 3'-hydroxyl termini at single breaks in duplex DNA molecules. DNA ligase I is responsible for the majority of DNA ligase activity present in proliferating cells among four different forms of DNA ligases, designated DNA ligase I, II, III, and IV. In this study, we were interested in comparing DNA ligase I level in human tumors versus normal tissues and in studying whether the inhibition of DNA ligase I could lead to tumor cell death.

EXPERIMENTAL DESIGN

DNA ligase I level was measured by Western immunoblot assay in various human malignant tumor specimens and benign tissues obtained from patients, in peripheral blood lymphocytes obtained from healthy donors, and in human tumors grown in nude mice. We also have designed antisense oligonucleotides (ODNs) targeting the mRNA of DNA ligase I and tested whether DNA ligase I antisense ODNs could control tumor cell growth.

RESULTS

The amount of DNA ligase I enzyme in malignant tumors was considerably higher than that in benign normal tissues and peripheral blood lymphocytes. The level of DNA ligase I in human tumors grown in nude mice was also very high, and the expression of DNA ligase I appears to be constitutive during in vivo tumor development. We have observed that DNA ligase I antisense ODN inhibited tumor cell growth in a dose-response manner, but nonspecific control ODNs had little effect on the growth of the same cell lines.

CONCLUSIONS

The presence of DNA ligase I at higher levels in human tumors than in benign normal tissues and normal peripheral lymphocytes suggests DNA ligase I plays more of a role in proliferating cells than in resting cells. These results, together with our finding that DNA ligase I antisense ODNs can suppress tumor cell proliferation, warrant the design and testing of human DNA ligase I inhibitors as new anticancer agents.

The role of computed tomography scans in evaluating sinus disease in pediatric patients

OBJECTIVES

To determine the incidence and severity of sinus abnormalities in children undergoing computed tomography (CT) of the sinuses for suspected chronic sinusitis. To compare these findings with abnormalities noted on random CT scans.

METHODS

Sixty CT scans, performed for evaluation of sinus disease in symptomatic children aged 2-12, were compared with 50 CT scans of children aged 2-12 of the orbits or sinuses obtained for indications other than sinusitis. A staging system was applied to assess the severity of abnormalities.

RESULTS

Mucoperiosteal thickening was present in 60% of symptomatic and 46%, of random CT scans (logistic regression, P = 0.144). Children aged 2-4 and 9-12 had an increased prevalence of abnormalities in both groups, although these findings were not statistically significant (logistic regression, P = 0.817). Early stage sinus disease was present in the majority of random (96%) and symptomatic (85%) children.

CONCLUSIONS

There is a high incidence of mucoperiosteal thickening in the paranasal sinuses of children. CT scans of the sinuses should be obtained from children who are being considered for sinus surgery after failing the appropriate medical therapy. Decisions regarding the need for sinus surgery should not be solely based on imaging abnormalities.

Managing dysphagia in palliative care

Dysphagia is a common problem in patients with advanced cancer. The nursing management of this condition must pay equal attention to the various physical and psychological signs and symptoms to promote patient well-being and comfort.

Occult primary tumors of the head and neck: detection with 2-[F-18] fluoro-2-deoxy-D-glucose SPECT

PURPOSE

To evaluate 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) single photon emission computed tomography (SPECT) in the detection of clinically occult primary tumors of the upper aerodigestive tract.

MATERIALS AND METHODS

Eighteen patients with histologically proved cervical nodal metastasis from squamous cell carcinoma (SCC) underwent FDG SPECT; 17 also underwent computed tomography (CT) and one underwent magnetic resonance (MR) imaging. All 18 patients underwent direct panendoscopy and biopsy. Biopsy and imaging results were correlated.

RESULTS

Among 11 histologically proved primary tumors, FDG SPECT depicted nine tumors; CT depicted four lesions. Five patients had abnormal FDG uptake with negative biopsy results. Among five patients with normal SPECT findings, biopsy results were positive in two and negative in three. FDG SPECT at the initial reading had sensitivity of 81%, specificity of 38%, positive predictive value of 64%, and negative predictive value of 60% for detection of occult primary tumors.

CONCLUSION

FDG SPECT guidance of endoscopic biopsies in patients with occult primary SCCs of the head and neck has the potential to yield a higher rate of positive biopsy results than that traditionally expected from "blind" endoscopic procedures with "random" or "speculative" biopsy. FDG SPECT and CT are likely to remain complementary studies for the detection of occult primary tumors of the head and neck.

Nonnutritive sucking during tube feedings: effects on preterm neonates in an intensive care unit

Preterm neonates (mean 32 weeks' gestation, 1,300 gm birth weight) were provided a pacifier for nonnutritive sucking during tube feedings in the intensive care nursery. Their clinical course, subsequent bottle feeding behavior, and performance on the Brazelton Neonatal Behavior Assessment scale were compared with those of control group infants. The infants provided with pacifiers averaged 27 fewer tube feedings, started bottle feeding three days earlier, averaged a greater weight gain per day, and were discharged eight days earlier for an average hospital cost savings of approximately $3,500. Formula intake was similar for the two groups, although nurses appeared to provide more feeding stimulation for the control infants. On the Brazelton scale, the infants provided with pacifiers showed weak reflexes more frequently. Increased restfulness and diminished activity level in these infants may have contributed to the appearance of weak reflexes. The consistency between these findings and those of previous investigators suggests that the provision of a pacifier for nonnutritive sucking during tube feedings may be a cost-effective form of intervention.

Teenage, lower-class, black mothers and their preterm infants: an intervention and developmental follow-up

To assess the combined risks of being born preterm and to a teenage mother, and to evaluate the effects of an early intervention, preterm infants born to lower-class, black, teenage mothers were provided a home-based, parent-training intervention, and their development was then compared with that of nonintervention controls, of term infants of teenage mothers, and of term and preterm infants of adult mothers. Despite equivalence on prenatal care, factors which placed the preterm infant of the teenage mother at greater risk at birth were the small-for-date size of the infant and the less realistic developmental milestones and child rearing attitudes expressed by the mother. The preterm infants of teenage mothers who received intervention showed more optimal growth, Denver scores, and face-to-face interactions at 4 months. Their mothers rated their infants' temperaments more optimally, expressed more realistic developmental milestones and child-rearing attitudes, and received higher ratings on face-to-face interactions. At 8 months, the intervention group received superior Bayley mental, Caldwell, and infant temperament scores.