[Research on the standard limits for vinyl chloride and trichloroethylene in the "Standards for Drinking Water Quality（GB5749-2022）" in China]

The usage of vinyl chloride and trichloroethylene in China has been increasing year by year, and they have been detected in both drinking water and environmental water, making them important environmental pollutants. Based on the latest research results on the health effects of vinyl chloride and trichloroethylene, the newly issued, "Standards for Drinking Water Quality (GB5749-2022)" in China has adjusted the standard limit of vinyl chloride from 0.005 mg/L to 0.001 mg/L and the standard limit of trichloroethylene from 0.07 mg/L to 0.02 mg/L. This article analyzed and discussed the relevant technical contents for determining the above standard limits, including the levels and exposure conditions of vinyl chloride and trichloroethylene in the water environment, health effects, derivation of safety reference values, and determination of hygiene standard limits. Suggestions were also made for the implementation of this standard.

[New mutation site of SEC23B gene in type Ⅱ congenital erythrocythememia anemia: one case report and literatures review]

Objective: To enrich the gene mutation sites and accumulate treatment experience of congenital dyserythropoietic anemia (CDA) type Ⅱ by reporting one case of CDA patient with new mutation site of SEC23B and was successfully treated by homozygous allogeneic hematopoietic stem cell transplantation (allo-HSCT) . Methods: The mutation within SEC23B gene in a child case with the reduced hemoglobin for more than 3 months, and his family were analyzed in combination with literatures review. Results: A 3-day 5-month female child was admitted due to "decreasing hemoglobin for more than 3 months" , blood routine test showed HGB 44 g/L, positive for acid hemolysis test (Ham test) . Bone marrow showed that the proportion of erythroid line was 69%, mainly middle and late juvenile erythrocytes, binuclear and odd nucleated erythrocytes could be observed, and nuclear fragmentation and nuclear budding could be seen occasionally in nucleated erythrocytes, transmission electron microscopy disclosed that bone marrow harbored the typical double-layer membrane structure of nuclear erythrocytes. There were two unreported new mutation sites in the SEC23B gene, including 1504 G>C/wt and c. 2254-2255 insert A/wt. The two mutations were derived from the father and mother of the child respectively. At the late stage, the child was successfully treated with allo-HSCT, the original mutation turned negative. Conclusion: This study reported the mutation type of SEC23B gene insertion for the first time in China. Allo-HSCT could be utilized as a treatment for CDA.

Cerebrospinal Fluid Orexin A Levels and Autonomic Function in Kleine-Levin Syndrome

STUDY OBJECTIVES

Kleine-Levin syndrome (KLS) is a rare disorder of relapsing sleepiness. The hypothesis was that the syndrome is related to a change in the vigilance peptide orexin A.

METHODS

From 2002 to 2013, 57 patients with relapsing hypersomnolence were clinically assessed in a referral academic center in Beijing, China, and 44 (28 males and 16 females; mean age 18.3 ± 8.9 y (mean ± standard deviation, range 9-57 y) were determined to have clinical and behavioral criteria consistent with KLS. Cerebrospinal fluid orexin A levels and diurnal blood pressure were measured in relapse versus remission in a subgroup of patients.

RESULTS

Presenting symptoms included relapsing or remitting excessive sleepiness-associated parallel complaints of cognitive changes (82%), eating disorders (84%); depression (45%); irritability (36%); hypersexuality (18%); and compulsions (11%). Episodes were 8.2 ± 3.3 days in duration. In relapse, diurnal values for blood pressure and heart rate were lower (P < 0.001). In a subgroup (n = 34), cerebrospinal fluid orexin A levels were ∼31% lower in a relapse versus remission (215.7 ± 81.5 versus 319.2 ± 95.92 pg/ml, P < 0.001); in three patients a pattern of lower levels during subsequent relapses was documented.

CONCLUSIONS

There are lower orexin A levels in the symptomatic phase than in remission and a fall and rise in blood pressure and heart rate, suggesting a role for orexin dysregulation in KLS pathophysiology.

HLA-DQ association and allele competition in Chinese narcolepsy

In Japanese, Koreans and Caucasians, narcolepsy/hypocretin deficiency is tightly associated with the DRB1*15:01-DQA1*01:02-DQB1*06:02 haplotype. Studies in African-Americans suggest a primary effect of DQB1*06:02, but this observation has been difficult to confirm in other populations because of high linkage disequilibrium between DRB1*15:01/3 and DQB1*06:02 in most populations. In this study, we studied human leucocyte antigen (HLA) class II in 202 Chinese narcolepsy patients (11% from South China) and found all patients to be DQB1*06:02 positive. Comparing cases with 103 unselected controls, and 110 and 79 controls selected for the presence of DQB1*06:02 and DRB1*15:01, we found that the presence of DQB1*06:02 and not DRB1*15:01 was associated with narcolepsy. In particular, Southern Chinese haplotypes such as the DRB1*15:01-DQA1*01:02-DQB1*06:01 and DRB1*15:01-DQA1*01:02-DQB1*05 were not associated with narcolepsy. As reported in Japanese, Koreans, African-Americans and Caucasians, additional protective effects of DQA1*01 (non-DQA1*01:02) and susceptibility effects of DQB1*03:01 were observed. These results illustrate the extraordinary conservation of HLA class II effects in narcolepsy across populations and show that DRB1*15:01 has no effect on narcolepsy susceptibility in the absence of DQB1*06:02. The results are also in line with a previously proposed 'HLA-DQ allelic competition model' that involves competition between non-DQA1*01:02, non-DQB1*06:02 'competent' (able to dimerize together) DQ1 alleles and the major DQα*01:02/ DQβ*06:02 narcolepsy heterodimer to reduce susceptibility.

TCRA, P2RY11, and CPT1B/CHKB associations in Chinese narcolepsy

OBJECTIVES

Polymorphisms in the TCRA and P2RY11, two immune related genes, are associated with narcolepsy in Caucasians and Asians. In contrast, CPT1B/CHKB polymorphisms have only been shown to be associated with narcolepsy in Japanese, with replication in a small group of Koreans. Our aim was to study whether these polymorphisms are associated with narcolepsy and its clinical characteristics in Chinese patients with narcolepsy.

METHODS

We collected clinical data on 510 Chinese patients presenting with narcolepsy/hypocretin deficiency. Patients were included either when hypocretin deficiency was documented (CSF hypocretin-1≤110 pg/ml, n=91) or on the basis of the presence of clear cataplexy and HLA-DQB1∗0602 positivity (n=419). Genetic data was compared to typing obtained in 452 controls matched for geographic origin within China. Clinical evaluations included demographics, the Stanford Sleep Inventory (presence and age of onset of each symptom), and Multiple Sleep Latency Test (MSLT) data.

RESULTS

Chinese narcolepsy was strongly and dose dependently associated with TCRA (rs1154155C) and P2RY11 (rs2305795A) but not CPT1B/CHKB (rs5770917C) polymorphisms. CPT1B/CHKB polymorphisms were not associated with any specific clinical characteristics. TCRA rs1154155A homozygotes (58 subjects) had a later disease onset, but this was not significant when corrected for multiple comparisons, thus replication is needed. CPT1B/CHKB or P2RY11 polymorphisms were not associated with any specific clinical characteristics.

CONCLUSIONS

The study extends on the observation of a strong multiethnic association of polymorphisms in the TCRA and P2RY11 with narcolepsy, but does not confirm the association of CPT1B/CHKB (rs5770917) in the Chinese population.

Narcolepsy onset is seasonal and increased following the 2009 H1N1 pandemic in China

OBJECTIVE

Narcolepsy is caused by the loss of hypocretin/orexin neurons in the hypothalamus, which is likely the result of an autoimmune process. Recently, concern has been raised over reports of narcolepsy in northern Europe following H1N1 vaccination.

METHODS

The study is a retrospective analysis of narcolepsy onset in subjects diagnosed in Beijing, China (1998-2010). Self-reported month and year of onset were collected from 629 patients (86% children). Graphical presentation, autocorrelations, chi-square, and Fourier analysis were used to assess monthly variation in onset. Finally, 182 patients having developed narcolepsy after October 2009 were asked for vaccination history.

RESULTS

The occurrence of narcolepsy onset was seasonal, significantly influenced by month and calendar year. Onset was least frequent in November and most frequent in April, with a 6.7-fold increase from trough to peak. Studying year-to-year variation, we found a 3-fold increase in narcolepsy onset following the 2009 H1N1 winter influenza pandemic. The increase is unlikely to be explained by increased vaccination, as only 8 of 142 (5.6%) patients recalled receiving an H1N1 vaccination. Cross-correlation indicated a significant 5- to 7-month delay between the seasonal peak in influenza/cold or H1N1 infections and peak in narcolepsy onset occurrences.

INTERPRETATION

In China, narcolepsy onset is highly correlated with seasonal and annual patterns of upper airway infections, including H1N1 influenza. In 2010, the peak seasonal onset of narcolepsy was phase delayed by 6 months relative to winter H1N1 infections, and the correlation was independent of H1N1 vaccination in the majority of the sample.

Presentations of primary hypersomnia in Chinese children

OBJECTIVE

To retrospectively describe childhood presentations of primary hypersomnia with an emphasis on narcolepsy-cataplexy in a Chinese population.

METHODS

A total of 417 children (< 18 years old) successively presenting with complaints of hypersomnia without anatomic cause or sleep apnea risk were evaluated using the Stanford Sleep Inventory, human leukocyte antigen (HLA) DQB1*0602 typing, and MSLT recordings. CSF hypocretin-1 was measured in 47 cases to document hypocretin deficiency. A subgroup ("narcolepsy/hypocretin deficiency") with likely hypocretin deficiency (low hypocretin-1 or HLA positive with clear-cut cataplexy) was further examined for presentations prior to, around, or after puberty.

RESULTS

Narcolepsy with (n = 361) or without (n = 17) cataplexy presented at an earlier age and with increased male predominance when compared to idiopathic hypersomnia (n = 39, P < 0.01). Nearly 70% of those with narcolepsy/hypocretin deficiency (n = 271) had disease onset before age 10 y, and 15% had onset before age 6, an unusually young age distribution. Onset was prior to puberty in 78% of cases. Clinical features were similar in presentations across puberty groups except for sleep paralysis, which increased in frequency with age/puberty. Mean sleep latency (MSL) decreased and the number of sleep onset REM periods (SOREMPs) increased with age/puberty, but MSLT diagnosis criteria (MSL ≤ 8 min, ≥ 2 SOREMPs) were similarly positive across groups. Familial clustering was present in only 1.7% of probands.

CONCLUSION

In children presenting with a complaint of primary hypersomnia to a sleep clinic in China, 86% (361/417) meet criteria for narcolepsy with cataplexy. Puberty did not affect positivity on the MSLT as a diagnostic feature. Sleep paralysis was the only symptom that increased with increasing age. In addition, narcolepsy with cataplexy in our clinic population appeared to begin at a younger age than usually reported in other studies.

Effect of active and passive cigarette smoking on CYP1A2-mediated phenacetin disposition in Chinese subjects

The effect of active and passive cigarette smoking on CYP1A2-mediated phenacetin disposition was evaluated in a controlled study of 36 healthy Chinese subjects. Each subject was administered a single oral dose of phenacetin (900 mg), and frequent blood samples were taken for up to 12 hours for simultaneous high-pressure liquid chromatography determinations of plasma concentrations of phenacetin and metabolically derived paracetamol. Compared with values observed in controls not exposed to cigarette smoking, subjects who smoked 7 to 40 (median, 20) cigarettes per day exhibited a 2.5-fold higher phenacetin apparent oral clearance (7.2, 4.3-12.0 L x h(-1) x kg(-1) vs 2.9, 1.8-4.6 L x h(-1) x kg(-1) [geometric means, 95% confidence intervals]; n = 12, p < 0.05). In subjects exposed to passive smoking, phenacetin's apparent oral clearance (3.6, 2.0-46.6 L x h(-1) x kg(-1), n = 12) was intermediate between the values observed in the two other groups. Plasma paracetamol levels were moderately lower in active smokers than in passive smokers and controls. These results demonstrated that, in contrast to results found in previous studies, Chinese subjects were fully susceptible to the inducing effect of cigarette smoke on CYP1A2 activity.