Genetic identification of tissues and cell types underlying attention-deficit/hyperactivity disorder

BACKGROUND

Genome-wide association studies (GWASs) have identified numerous genetic variants associated with attention-deficit/hyperactivity disorder (ADHD), which is considered highly genetically heritable. However, because most of the variants located in the non-coding region of the human genome, the onset of ADHD requires further exploration.

METHODS

The risk genes involved in ADHD were identified by integrating GWAS summary data and expression quantitative trait locus (eQTL) data using summary-data-based Mendelian randomization (SMR) method. We then used a stratified linkage disequilibrium score regression (LDSR) method to estimate the contribution of ADHD-relevant tissues to its heritability to screen out disease-relevant tissues. To determine the ADHD-relevant cell types, we used an R package for expression-weighted cell type enrichment (EWCE) analysis.

RESULTS

By integrating the brain eQTL data and ADHD GWAS data using SMR, we identified 247 genes associated with ADHD. The LDSR applied to specifically expressed genes results showed that the ADHD risk genes were mainly enriched in brain tissue, especially in the mesencephalon, visual cortex, and frontal lobe regions. Further cell-type-specific analysis suggested that ADHD risk genes were highly expressed in excitatory neurons.

CONCLUSION

The study showed that the etiology of ADHD is associated with excitatory neurons in the midbrain, visual cortex, and frontal lobe regions.

[Risk assessment for thyroid (131)I exposure among nuclear medical staff]

Objective: To explore the main risk factors and to assess the risk of thyroid (131)I exposure among nuclear medical workers. Methods: From March to October in 2019, cluster sampling was adopted to collect the number of (131)I automatic packer and patients treated for thyroid cancer, hyperthyroidism and liven cancer used (131)I, the practicing categories, job rotation and (131)I operation condition of nuclear medical staff were also investegated in the 21 nuclear medicine hospitals in Fujian Province that carried out (131)I nuclide diagnosis and treatment in 2018. (131)I aerosol and personnel thyroid (131)I were measured in 20 hospitals using (131)I for thyroid cancer or hyperthyroidism. The main risk factors leading to thyroid (131)I exposure of nuclear medical staff were found and aninternal exposure risk assessment model was established. Results: The detection rate of (131)I aerosol and personnel thyroid (131)I were 80.0% (16/20) and 25.5% (62/243) in 20 hospitals. The situation of packaging and administration about (131)I in the nearly 10 effective half-life, the concentration of (131)I aerosol in the nuclear medicine workplace, the number of patients treated with (131)I for thyroid cancer or hyperthyroidism were the main risk factors leading to thyroid (131)I internal exposure (OR=5.857, 6.808, 1.983, 1.150, P<0.05) . Conclusion: (131)I exposure is common among nuclear medical workers, attention should be paid to the protection of internal radiation, strengthen the control of main risk factors, so as to reduce the risk of internal radiation.

Gastroscopic treatment of membranous duodenal stenosis in infants and children: report of 6 cases

OBJECTIVE

To investigate the efficacy of gastroscopic treatment in the treatment of membranous duodenal stenosis.

METHODS

We performed a retrospective study of 6 patients with membranous duodenal stenosis, aging from 7days to 37months, who underwent gastroscopic balloon dilatation in a children's hospital between January 2012 and December 2013. All surgical procedures of balloon dilatation were performed under direct gastroscopic vision. The balloon dilators with diameter 8mm and 10mm for neonates and children aged over one month, respectively, were placed through the foramen of the membranous stenosis. The septum in the membranous stenosis was gradually extended by increasing diameter of the balloon dilator. The residual septum was removed by gastroscopic electrocauterization.

RESULTS

The membranous stenosis in duodenum of all children was successfully expanded by gastroscopic balloon dilatation, and only one case with residual septum received gastroscopic electrocauterization. No complications such as bleeding, intestinal perforation, etc., were observed. Postoperative radiography using iodine-based contrast media showed that the gastrointestinal tract was unobstructed. During a follow-up period ranging from 3 to 24months, all patients ate normally without vomiting and abdominal distension and grew normally.

CONCLUSION

Gastroscopic balloon dilatation is an effective method in the treatment of membranous duodenal stenosis in children. For the patients with residual septum, they can be cured by using gastroscopic electrocauterization.

Attributable causes of cancer in China

BACKGROUND

Most cancers are due to modifiable lifestyle and environmental risk factors, and are potentially preventable. No studies have provided a systematic quantitative assessment of the burden of cancer mortality and incidence attributable to known risk factors in China.

METHODS

We calculated the proportions of cancer deaths and new cases attributable to known risk factors in China, based on the prevalence of exposure around 1990 and national data on cancer mortality and incidence for the year 2005.

RESULTS

Chronic infection is the main risk factor for cancer in China, accounting for 29.4% of cancer deaths (31.7% in men and 25.3% in women), followed by tobacco smoking (22.6% with 32.7% in men and 5.0% in women), low fruit intake (13.0%), alcohol drinking (4.4%), low vegetable intake (3.6%) and occupational exposures (2.7%). The remaining factors, including environmental agents, physical inactivity, the use of exogenous hormones and reproductive factors are each responsible for <1.0%.

CONCLUSIONS

Modifiable risk factors explain nearly 60% of cancer deaths in China, with a predominant role of chronic infection and tobacco smoking. Our findings could provide a basis for cancer prevention and control programs aimed at reducing cancer risk in other developing countries.

[Non-steroidal anti-inflammatory drugs and chemoprevention of digestive cancer]

Recent epidemiology and laboratory studies indicate that regular taking of aspirin and other non-steroidal anti-inflammatory drugs(NSAIDs) may reduce the risk of colorectal, esophageal, stomach and pancreatic cancers and other digestive cancers. Thus, aspirin and other NSAIDs may be an effective chemoprevention agent for digestive cancers. On the other hand, this protection effort may be beneficial to the course of the intervention, regression and prevention of cancer lesions. The possible mechanism of NSAIDs chemoprevention may be: (1) reducing the synthesis of prostaglandin(PG) and inhibiting cyclo-oxygenase(COX) activity; (2) inducing apoptosis in epithelial cells of the gastro-intestinal origin; (3) obstructing signaling transduction pathways of COX and PG. Now, chemoprevention of NSAIDs has become focus of research on cancer secondary prevention, as its protective effects of chemoprevention of digestive cancer have been determined. NSAIDs, especially selective COX-2 inhibitor may be a novel useful chemoprevention agents for digestive cancer and their precursor lesions in future.

Regulation of the expression of nitric oxide synthase and leishmanicidal activity by glycoconjugates of Leishmania lipophosphoglycan in murine macrophages

Lipophosphoglycan (LPG) glycoconjugates from promastigotes of Leishmania were not able to induce the expression of the cytokine-inducible nitric oxide synthase (iNOS) by the murine macrophage cell line, J774. However, they synergize with interferon gamma to stimulate the macrophages to express high levels of iNOS. This synergistic effect was critically time-dependent. Preincubation of J774 cells with the LPG glycans 4-18 h before stimulation with interferon gamma resulted in a significant reduction in the expression of iNOS mRNA and of NO synthesis, compared with cells preincubated with culture medium alone. The regulatory effect on the induction of iNOS by LPG is located in the LPG phosphoglycan disaccharide backbone. Synthetic fragments of this backbone had a similar regulatory effect on NO synthesis. Further, the production of NO by activated macrophages in the present system was correlated directly with the leishmanicidal capacity of the cells. These data therefore demonstrate that LPG glycoconjugates have a profound effect on the survival of Leishmania parasites through their ability to regulate the expression of iNOS by macrophages.