[Study on visual evoked related potentials in young adults of different COMT genotypes by using a numeric working memory task].

AIM: To explore the change of number working memory ability in healthy young adults, a continuous 3-back number working memory task were performed for an hour and 12 Blocks according to different COMT genotypes of young adults. METHODS: 18 different genotype subjects were chosen from 112 healthy young adults, P3 event-related potentials was utilized to observe the relationship between this COMT polymorphism and cortical physiology in a continuous working memory task. RESULTS: Subjects bearing the Val/Val homozygote had significantly higher mean P3 amplitudes than Val/Met heterozygote (P < 0.01), however, no significant differences in comparison to Met/Met homozygote. CONCLUSION: Val/Met Heterozygote subjects are associated with the poorest performance of working memory. There is a relationship between COMT genotype and P3 visual event-related potentials evoked from 3-back task.

[Role of sGC-cGMP pathway in CO-mediated regulation of respiratory rhythm].

OBJECTIVE: To identify the role of soluble guanylyl cyclase-cyclic guanine monophosphate (sGC-cGMP) pathway in the carbon monoxide (CO) mediating regulation of respiratory rhythm from the medulla oblongata. METHODS: Medullary slices of newborn Sprague-Dawley rats were prepared for the experiment. The electrophysiological experiment comprised 5 groups (each with 8 slices), each of which were perfused with artificial cerebrospinal fluid (ACSF control group), CO (exogenous CO group), 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one (a specific inhibitor of sGC, ODQ group), ODQ+CO (ODQ+CO group), and dimethyl sulfoxide (vehicle of ODQ, DMSO group), respectively. The burst frequency (BF) of hypoglossal rootlets was recorded as an index of rhythmic respiratory activity. Radioimmunoassay was employed to determine cGMP levels of the medullary slices of the ACSF control group, exogenous CO group, ODQ group and ODQ+CO group (n=6/ group). RESULTS: The exogenous CO decreased the BF (P < 0.05) and increased the cGMP level (P < 0.05). The ODQ increased the BF (P < 0.05) and decreased the cGMP level (P < 0.05). No significant changes were found in the BF and cGMP levels when CO and ODQ applied simultaneously (P > 0.05), but the BF increased (P < 0.05) after the drug perfusion ended. CONCLUSION: sGC-cGMP pathway may play an important role in the CO mediated regulation of respiratory rhythm from the medulla oblongata.

[Association of polymorphisms of 1772 (C-->T) and 1790 (G-->A) in HIF1A gene with hypoxia adaptation in high altitude in Sherpas].

OBJECTIVE: To investigate the association of single nucleotide polymorphisms (SNPs) of 1772 (C-->T) and 1790 (G-->A) in exon 12 of hypoxia-inducible factor 1, alpha subunit gene (HIF1A) with hypoxia adaptation in high altitude in Sherpas. METHODS: The blood samples were chosen from 148 Sherpas in Tibet high altitude and 90 Han nationality healthy people in Guangdong province, and from which genomic DNA was extracted. The single nucleotide polymorphisms of 1772(C-->T) and 1790(G-->A) in exon 12 of HIF1A gene were examined by restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR). RESULTS: The genotype frequency of HIF1A gene 1790 (G-->A) in Sherpas and Han nationality was 57.43% versus 75.56% in GG genotype, 37.84% versus 21.11% in GA genotype and 4.73% versus 3.33% in AA genotype. GG genotype frequency in Sherpas was lower than that in Han nationality (P<0.01), while GA genotype frequency in Sherpas was higher than that in Han nationality (P<0.01). No significant difference in CC, CT and TT genotype frequency of 1772(C-->T) was shown between two groups respectively. The total frequency of CC + GA, CT + AA, TT + GA and TT + AA in Sherpas was higher than that in Han nationality. CONCLUSION: Polymorphisms of HIF1A gene 1790 (G-->A) are associated with hypoxia adaptation in high altitude in Sherpas. GA and AA genotype may be benefit to hypoxia adaptation, and it is worthy of deep-going investigation.

[Single nucleotide polymorphisms study of surfactant protein A gene between Tibet Sherpas and Guangdong Chinese Hans].

AIM: To investigate the relationship between single nucleotide polymorphisms(SNPs) of surfactant protein A(SP-A) gene of Chinese Han and Sherpas and their adaptation to high altitude hypoxia. METHODS: The genotypes of 90 Chinese Han in Guangdong and 104 Sherpas in Tibet were analyzed by sequence special primer polymerase chain reaction(SSP-PCR) sequencing the surfactant protein A gene. RESULTS: The frequencies of genotypes and alleles at SP-A1 1544 locus showed no difference between the Sherpas and the Chinese Han (P>0.05). However, the frequencies of genotypes C/C, C/T and T/T at SP-A1 3241 locus were 75.0%, 22.1% and 2.9%, respectively in Sherpas, difference to Han population, they were 50.0%, 35.6% and 14.4%, respectirely(P<0.05). Whilst in Sherpas allele frequencies of C and T were 86.1% and 13.9% respectively but they were 67.8% and 32.2% respectively in the Chinese Han(P<0.05); The frequencies of C/C, A/C and A/A at SP-A2 3265 locus were 37.5%, 53.8%, and 8.7%, respectively in the Sherpas were also difference to Chinese Han, they were 63.3%, 30.0%, and 6.7%, respectively. Whilst allele frequencies of C and A were 64.4% and 35.6% in Sherpas but 78.3% and 21.7% in Chinese Han, which showed statistically difference between two groups(P<0.05). CONCLUSION: There were statistically differences of genotypes and alleles at SP-A2 3265 locus in Hans and Sherpas. SNP in SP-A2 at 3265 may be related to the adaptation of Sherpas to high altitude hypoxia.

[A study on the relationship between glutathione S-transferases gene polymorphism and susceptibility response to hypoxia].

AIM: To investigate the relationship between glutathione S-transferases gene polymorphism and susceptibility response to hypoxia. METHODS: In the case-control study, the gene polymorphisms of glutathione S-transferases were tested in Tibetan mountaineers and sea-level Han Chinese by multiple-PCR and PCR-RELP. RESULTS: The frequency of GSTT1 null genotype was significant different between Tibetan mountaineers and sea-level Han Chinese (P < 0.05), OR = 1.86 (95% CI = 1.01-3.39), and also for GSTP(1-105) mutant genotype in two groups (P < 0.01), OR = 2.19 (95% CI = 1.16-4.13). There was significant difference between A allele and G allele of GSTP(1-105) groups (P < 0.01). There was no difference for GSTM1 null genotype between two groups (P > 0.05), OR = 0.78 (95% CI = 0.43 - 1.42). CONCLUSION: GSTT1 and GSTP(1-105) genotype may be associated with susceptibility response to altitude hypoxia.

[Effects of electric stimulation on circadian rhythm of plasma cortisone in soldiers].

OBJECTIVE: To observe the effects of electric stimulation on the circadian rhythm of plasma cortisone in soldiers. METHODS: Electric stimulation or phototherapy was respectively performed in the popliteal region (behind the knee) of the soldiers at different time points and radio immunal assay was utilized to examine the plasma cortisone concentration. RESULTS: The plasma cortisone concentration exhibited obvious circadian rhythmicity. At the 3 time points before the lowest core temperature occurred, treatments with electric stimulation or phototherapy resulted in delayed phase of circadian cortisone rhythm, while the same treatments given at the 3 time points after the lowest core temperature caused earlier arrival of the phase. No changes in the rhythm phase in response to treatments at other time points. CONCLUSION: Both of electric stimulation and phototherapy can adjust the phase of the cortisol circadian rhythmicity, and the phase curve displayed photic response to the treatments.