Domain Specific Changes in Cognition at High Altitude and Its Correlation with Hyperhomocysteinemia

Though acute exposure to hypobaric hypoxia is reported to impair cognitive performance, the effects of prolonged exposure on different cognitive domains have been less studied. The present study aimed at investigating the time dependent changes in cognitive performance on prolonged stay at high altitude and its correlation with electroencephalogram (EEG) and plasma homocysteine. The study was conducted on 761 male volunteers of 25–35 years age who had never been to high altitude and baseline data pertaining to domain specific cognitive performance, EEG and homocysteine was acquired at altitude ≤240 m mean sea level (MSL). The volunteers were inducted to an altitude of 4200–4600 m MSL and longitudinal follow-ups were conducted at durations of 03, 12 and 18 months. Neuropsychological assessment was performed for mild cognitive impairment (MCI), attention, information processing rate, visuo-spatial cognition and executive functioning. Total homocysteine (tHcy), vitamin B₁₂ and folic acid were estimated. Mini Mental State Examination (MMSE) showed temporal increase in the percentage prevalence of MCI from 8.17% on 03 months of stay at high altitude to 18.54% on 18 months of stay. Impairment in visuo-spatial executive, attention, delayed recall and procedural memory related cognitive domains were detected following prolonged stay in high altitude. Increase in alpha wave amplitude in the T3, T4 and C3 regions was observed during the follow-ups which was inversely correlated (r = −0.68) to MMSE scores. The tHcy increased proportionately with duration of stay at high altitude and was correlated with MCI. No change in vitamin B₁₂ and folic acid was observed. Our findings suggest that cognitive impairment is progressively associated with duration of stay at high altitude and is correlated with elevated tHcy in the plasma. Moreover, progressive MCI at high altitude occurs despite acclimatization and is independent of vitamin B₁₂ and folic acid.     

Autonomic Cardiovascular Responses in Acclimatized Lowlanders on Prolonged Stay at High Altitude: A Longitudinal Follow Up Study

Acute exposure to hypobaric hypoxia at high altitude is reported to cause sympathetic dominance that may contribute to the pathophysiology of high altitude illnesses. The effect of prolonged stay at high altitude on autonomic functions, however, remains to be explored. Thus, the present study aimed at investigating the effect of high altitude on autonomic neural control of cardiovascular responses by monitoring heart rate variability (HRV) during chronic hypobaric hypoxia. Baseline electrocardiography (ECG) data was acquired from the volunteers at mean sea level (MSL) (<250 m) in Rajasthan. Following induction of the study population to high altitude (4500–4800 m) in Ladakh region, ECG data was acquired from the volunteers after 6 months (ALL 6) and 18 months of induction (ALL 18). Out of 159 volunteers who underwent complete investigation during acquisition of baseline data, we have only included the data of 104 volunteers who constantly stayed at high altitude for 18 months to complete the final follow up after 18 months. HRV parameters, physiological indices and biochemical changes in serum were investigated. Our results show sympathetic hyperactivation along with compromise in parasympathetic activity in ALL 6 and ALL 18 when compared to baseline data. Reduction of sympathetic activity and increased parasympathetic response was however observed in ALL 18 when compared to ALL 6. Our findings suggest that autonomic response is regulated by two distinct mechanisms in the ALL 6 and ALL 18. While the autonomic alterations in the ALL 6 group could be attributed to increased sympathetic activity resulting from increased plasma catecholamine concentration, the sympathetic activity in ALL 18 group is associated with increased concentration of serum coronary risk factors and elevated homocysteine. These findings have important clinical implications in assessment of susceptibility to cardio-vascular risks in acclimatized lowlanders staying for prolonged duration at high altitude.     

Elevated C-Reactive Protein Levels and Enhanced High Frequency Vasomotion in Patients with Ischemic Heart Disease during Brachial Flow-Mediated Dilation

Purpose

The physiological role of vasomotion, rhythmic oscillations in vascular tone or diameter, and its underlying mechanisms are unknown. We investigated the characteristics of brachial artery vasomotion in patients with ischemic heart disease (IHD).

Methods

We performed a retrospective study of 37 patients with IHD. Endothelial function was assessed using flow-mediated dilation (FMD), and power spectral analysis of brachial artery diameter oscillations during FMD was performed. Frequency-domain components were calculated by integrating the power spectrums in three frequency bands (in ms²) using the MemCalc (GMS, Tokyo, Japan): very-low frequency (VLF), 0.003–0.04 Hz; low frequency (LF), 0.04–0.15 Hz; and high frequency (HF), 0.15–0.4 Hz. Total spectral power (TP) was calculated as the sum of all frequency bands, and each spectral component was normalized against TP.

Results

Data revealed that HF/TP closely correlated with FMD (r = −0.33, p = 0.04), whereas VLF/TP and LF/TP did not. We also explored the relationship between elevated C-reactive protein (CRP) levels and vasomotion. HF/TP was significantly increased in subjects with high CRP levels (CRP;>0.08 mg/dL) compared with subjects with low CRP levels (0.052±0.026 versus 0.035±0.022, p<0.05). The HF/TP value closely correlated with CRP (r = 0.24, p = 0.04), whereas the value of FMD did not (r = 0.023, p = 0.84). In addition, elevated CRP levels significantly increased the value of HF/TP after adjustment for FMD and blood pressure (β = 0.33, p<0.05).

Conclusion

The HF component of brachial artery diameter oscillation during FMD measurement correlated well with FMD and increased in the presence of elevated CRP levels in subjects with IHD.     

高血压脑出血后血浆脂联素浓度变化及其与C- 反应蛋白相关性的研究*

目的:探讨高血压脑出血后血浆脂联素(APN)浓度变化及其与C-反应蛋白水平的相关性.方法:高血压脑出血病例82例列入研究组,健康者80例列入对照组,所有受试者均于发病6小时内抽血检测APN和C-反应蛋白(CRP).结果:研究组患者血清APN水平明显低于对照组,CRP水平明显高于对照组,差异有统计学意义(P＜0.05).随着高血压等级的升高,研究组患者APN值逐渐下降,CRP水平逐渐上升,但APN与CRP值的变化无显著差异(P＞0.05).结论:高血压脑出血后患者血浆脂联素浓度变化与CRP具有负相关性.     

Levels of C-Reactive Protein Associated with High and Very High Cardiovascular Risk Are Prevalent in Patients with Rheumatoid Arthritis

Objective

C-reactive protein (CRP) levels>3 mg/L and>10 mg/L are associated with high and very high cardiovascular risk, respectively, in the general population. Because rheumatoid arthritis (RA) confers excess cardiovascular mortality, we determined the prevalence of these CRP levels among RA patients stratified on the basis of their RA disease activity.

Methods

We evaluated physician and patient global assessments of disease activity, tender and swollen 28 joint counts, erythrocyte sedimentation rate (ESR), and CRP measured in a single clinic visit for 151 RA patients. Disease activity was calculated using the Clinical Disease Activity Index (CDAI) and the Disease Activity Score 28 Joints (DAS28-ESR and DAS28-CRP).

Results

Median CRP level was 5.3 mg/L. 68% of patients had CRP>3 mg/L, and 25% had CRP>10 mg/L. Of those with 0–1 swollen joints (n = 56), or 0–1 tender joints (n = 81), 64% and 67%, respectively, had CRP>3 mg/L, and 23% and 20%, respectively, had CRP>10 mg/L. Of those with remission or mildly active disease by CDAI (n = 58), DAS28-ESR (n = 39), or DAS28-CRP (n = 70), 49–66% had CRP>3 mg/L, and 10–14% had CRP>10 mg/L. Of patients with moderate disease activity by CDAI (n = 51), DAS28-ESR (n = 78), or DAS28-CRP (n = 66), 67–73% had CRP>3 mg/L, and 25–33% had CRP>10 mg/L.

Conclusion

Even among RA patients whose disease is judged to be controlled by joint counts or standardized disease scores, a substantial proportion have CRP levels that are associated high or very high risk for future cardiovascular events in the general population.     

A Natural Fluorescent Protein That Changes Its Fluorescence Color during Maturation

The gene of a new red fluorescent protein zoan2RFP from coral polyp Zoanthus sp., a homologue of the known green fluorescent protein from the jellyfish Aequorea victoria, was cloned. At early stages of maturation, zoan2RFP exhibits green fluorescence, which then turns to the red one. A similar phenomenon was recently reported for the E5 mutant of the red fluorescent coral protein DsRed. Zoan2RFP differs from E5 by faster maturation kinetics and the complete disappearance of green fluorescence in the mature protein. Naturally occurring proteins of this type can be considered as intermediate forms between the green and red fluorescent proteins, which are formed during the microevolution of fluorescent proteins.     

Changes in the Asynchronicity of Transmitter Release at the Neuromuscular Junction during Prolonged High-Frequency Stimulation

In experiments on neuromuscular junctions in the frog m. cutaneous-pectoris, changes in the intensity and asynchronicity of transmitter release during high-frequency (10 and 50 sec^-1) rhythmic stimulation of the motor nerve were investigated using extracellular recording. At low extracellular Ca²⁺ concentrations, rhythmic stimulation resulted in a gradual enlargement of the quantum content of end-plate currents (EPC), the so-called facilitation. The latter phenomenon was accompanied by an increase in the average value and variance of synaptic delays of single-quantum EPC, a shift of the main mode of their distribution towards greater values, and an increase in the latency of the nerve ending responses. The above-described changes reduce the magnitude of facilitation in the neuromuscular synapse.     

Volume Regulation and Renal Function at High Altitude across Gender

Aims

We investigated changes in volume regulating hormones and renal function at high altitudes and across gender.

Methodology

Included in this study were 28 subjects (n = 20 males; n = 8 females. ages: 19 – 65 yrs), who ascended to a height of 3440m (HA1), on the 3^rd day and to 5050m (HA2), on the 14^th day. Plasma and urinary creatinine and urinary osmolality as well as plasma levels of plasma renin activity (PRA), Aldosterone, antidiuretic hormone (ADH), and atrial natriuretic peptide (ANP) were measured. The plasma volume loss (PVL) was estimated from plasma density and hematocrit. Glomerular filtration rate (GFR) was measured based on nocturnal (9 hour) creatinine clearance; this was compared with various methods for estimation of GFR.

Results

The mean 24-hour urine production increased significantly in both sexes across the expedition. But PVL reached significance only in males. No changes in Na⁺ in plasma, urine or its fractional excretion were seen at both altitudes. Urinary osmolality decreased upon ascent to the higher altitudes. ADH and PRA decreased significantly at both altitudes in males but only at HA2 in females. However, no changes in aldosterone were seen across the sexes and at different altitudes. ANP increased significantly only in males during the expedition. GFR, derived from 9-h creatinine clearance (CreaCl), decreased in both sexes at HA1 but remained stable at HA2. Conventional Crea[p]-based GFR estimates (eGFR) showed only poor correlation to CreaCl.

Conclusions

We report details of changes in hormonal patterns across high altitude sojourn. To our knowledge we are not aware of any study that has examined these hormones in same subjects and across gender during high altitude sojourn. Our results also suggest that depending on the estimation formula used, eGFR underestimated the observed decrease in renal function measured by CreaCl, thus opening the debate regarding the use of estimated glomerular filtration rates at high altitudes.     

Plasminogen Activator Inhibitor-2 Polymorphism Associates with Recurrent Coronary Event Risk in Patients with High HDL and C-Reactive Protein Levels

The objective of this work was to investigate whether fibrinolysis plays a role in establishing recurrent coronary event risk in a previously identified group of postinfarction patients. This group of patients was defined as having concurrently high levels of high-density lipoprotein cholesterol (HDL-C) and C-reactive protein (CRP) and was previously demonstrated to be at high-risk for recurrent coronary events. Potential risk associations of a genetic polymorphism of plasminogen activator inhibitor-2 (PAI-2) were probed as well as potential modulatory effects on such risk of a polymorphism of low-density lipoprotein receptor related protein (LRP-1), a scavenger receptor known to be involved in fibrinolysis in the context of cellular internalization of plasminogen activator/plansminogen activator inhibitor complexes. To this end, Cox multivariable modeling was performed as a function of genetic polymorphisms of PAI-2 (SERPINB, rs6095) and LRP-1 (LRP1, rs1800156) as well as a set of clinical parameters, blood biomarkers, and genetic polymorphisms previously demonstrated to be significantly and independently associated with risk in the study population including cholesteryl ester transfer protein (CETP, rs708272), p22phox (CYBA, rs4673), and thrombospondin-4 (THBS4, rs1866389). Risk association was demonstrated for the reference allele of the PAI-2 polymorphism (hazard ratio 0.41 per allele, 95% CI 0.20-0.84, p=0.014) along with continued significant risk associations for the p22phox and thrombospondin-4 polymorphisms. Additionally, further analysis revealed interaction of the LRP-1 and PAI-2 polymorphisms in generating differential risk that was illustrated using Kaplan-Meier survival analysis. We conclude from the study that fibrinolysis likely plays a role in establishing recurrent coronary risk in postinfarction patients with concurrently high levels of HDL-C and CRP as manifested by differential effects on risk by polymorphisms of several genes linked to key actions involved in the fibrinolytic process.     

应用多普勒检测糖尿病患者颈动脉粥样硬化斑块并分析其与hs-CRP、HCY的关系

目的:探讨糖尿病患者血C反应蛋白(hs-CRP)、同型半胱氨酸(HCY)蛋白与颈动脉粥样硬化的关系.方法:收集58例糖尿病患者和42例体检正常者血浆,测定血hs-CRP、HCY蛋白水平,应用多普勒超声诊断仪检测颈动脉内膜、中层厚度(MT),观察颈动脉粥样斑块,并分析hs-CRP、HCY蛋白水平与颈动脉粥样硬化的关系.结果:糖尿病患者血hs-CRP、HCY含量、颈动脉MT和粥样斑块数较对照组明显增加(P<0.05);血hs-CRP、HCY水平与颈动脉MT及斑块数分别呈正相关(P<0.01).结论:hs-CRP、HCY可能在促进糖尿病及动脉粥样硬化的发生和发展中发挥了重要作用.可作为判断糖尿病患者病情程度和预后的评价指标.     

The Impact of Baseline Serum C-Reactive Protein and C-Reactive Protein Kinetics on the Prognosis of Metastatic Nasopharyngeal Carcinoma Patients Treated with Palliative Chemotherapy

Background

The aim of this study was to determine whether baseline C-reactive protein (CRP) levels and CRP kinetics predict the overall survival in metastatic nasopharyngeal carcinoma (mNPC) patients.

Methods

A total of 116 mNPC patients from January 2006 to July 2011 were retrospectively reviewed. Serum CRP level was measured at baseline and thereafter at the start of each palliative chemotherapy cycle for all patients.

Results

Patients with higher values of baseline CRP (≥ 3.4 mg/L) had significantly worse survival than those with lower baseline CRP values (< 3.4 mg/L). Patients were divided into four groups according to baseline CRP and CRP kinetics: (1) patients whose CRP < 3.4 mg/L and never elevated during treatment; (2) patients whose CRP < 3.4 mg/L and elevated at least one time during treatment; (3) patients whose CRP ≥ 3.4 mg/L and normalized at least one time during treatment; and (4) patients whose CRP ≥ 3.4 mg/L and never normalized during treatment. The patients were further assigned to non-elevated, elevated, normalized, and non-normalized CRP groups. Overall survival rates were significantly different among the four groups, with three-year survival rates of 68%, 41%, 33%, and 0.03% for non-elevated, elevated, normalized, and non-normalized CRP groups respectively. When compared with the non-elevated group, hazard ratios of death were 1.69, 2.57, and 10.34 in the normalized, elevated, and non-normalized groups (P < 0.001).

Conclusions

Baseline CRP and CRP kinetics may be useful to predict the prognosis of metastatic NPC patients treated with palliative chemotherapy and facilitate individualized treatment. A prospective study to validate this prognostic model is still needed however.     

Characterization of the Impacts of Living at High Altitude in Taif: Oxidative Stress Biomarker Alterations and Immunohistochemical Changes

At high elevations, the human body experiences a number of pathological, physiological, and biochemical changes, all of which have adverse impacts on human health and organ vitality. This study aimed to investigate the alterations in the liver and kidney biomarkers, oxidative stress markers, gene expression, and cellular histology of rats maintained at high altitudes and normal sea level. A total of twenty male Wistar rats at 2 months of age were randomly assigned to two groups. The rats in group A were maintained at normal sea level in Jeddah, whereas rats in group B were maintained in an area in Taif 2600 m above sea level. After 2 months of housing, orbital blood samples were collected for the analysis of significant biochemical indicators of oxidative stress biomarkers of the liver and kidneys. Liver and kidney tissues from both groups were taken to examine the hepatorenal changes occurring at the biochemical, histological, immunohistochemical, and genetic levels. The results revealed substantial increases in the serum levels of liver and kidney biomarkers (GPT, GOT, urea, and creatinine) and decreases in the serum levels of antioxidant biomarkers (SOD, catalase, GSH, and NO). In parallel, the levels of the malondialdehyde (MDA) tissue damage marker and inflammatory cytokines (IL-1β, TNF-α, and IFN-γ) were increased in the high-altitude group compared to the normal sea level group. In addition, there were significant alterations in the oxidative and inflammatory status of rats that lived at high altitude, with considerable upregulation in the expression of hepatic VEGF, type 1 collagen, Cox-2, TNF-α, and iNOS as well as renal EPASI, CMYC, HIF-α, and EGLN-2 genes in the high-altitude group compared with controls housed at normal sea level. In conclusion, living at high altitude induces hepatorenal damage and biochemical and molecular alterations, all of which may serve as critical factors that must be taken into account for organisms living at high altitudes.     

Inverse Association of Plasma IgG Antibody to Aggregatibacter actinomycetemcomitans and High C-Reactive Protein Levels in Patients with Metabolic Syndrome and Periodontitis

The association between clinically diagnosed periodontitis, a common chronic oral infection, and metabolic syndrome has been previously reported. The aim of this study was to investigate the association of plasma IgG levels against Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia, C-reactive protein, and periodontal status with metabolic syndrome. Plasma IgG levels and C-reactive protein were measured by enzyme-linked immunosorbent assay, and salivary levels of A. actinomycetemcomitans and P. gingivalis were determined by quantitative real-time polymerase chain reaction. Among 127 individuals aged 35–76 years, 57 participants had metabolic syndrome and severe periodontitis, 25 had metabolic syndrome and an absence of severe periodontitis, 17 healthy individuals had severe periodontitis, and 28 healthy individuals were without severe periodontitis. Patients with metabolic syndrome had reduced humoral immune response to A. actinomycetemcomitans (p = 0.008), regardless of their salivary levels or periodontitis status compared with healthy participants. The IgG antibody response to P. gingivalis, regardless of their salivary levels or participants’ health condition, was significantly higher in severe periodontitis patients (p<0.001). Plasma IgG titers for P. intermedia were inconsistent among metabolic syndrome or periodontal participants. Our results indicate that the presence of lower levels of IgG antibodies to A. actinomycetemcomitans (OR = 0.1; 95%CI 0.0–0.7), but not P. gingivalis, a severe periodontitis status (OR = 7.8; 95%CI 1.1–57.0), high C-reactive protein levels (OR = 9.4; 95%CI 1.0–88.2) and body mass index (OR = 3.0; 95%CI 1.7–5.2), are associated with the presence of metabolic syndrome. The role of the decreased IgG antibody response to A. actinomycetemcomitans, increased C-reactive protein levels on the association between periodontal disease and metabolic syndrome in a group of Thai patients is suggested.     

C-Reactive Protein for Predicting Prognosis and Its Gender-Specific Associations with Diabetes Mellitus and Hypertension in the Development of Coronary Artery Spasm

Background

While hypertension is negatively associated with coronary artery spasm (CAS), scarce data are available on diabetes mellitus in relation to CAS. In addition, outcome prediction in patients with CAS is challenging due to the lack of appropriate biomarkers. Therefore, we sought to identify the roles that gender, high-sensitivity C-reactive protein (hs-CRP), diabetes mellitus and hypertension play in CAS development and prognosis.

Methodology/Prinicpal Findings

Patients (350 women and 547 men) undergoing diagnostic coronary angiography with or without proven CAS but without obstructive stenosis were evaluated at long-term follow-up (median 102 months). Diabetic women and diabetic men with low hs-CRP levels had a low and high risk of CAS (odds ratio [OR]: 0.16, 95% confidence interval [CI]: 0.01–1.88 and OR: 5.02, 95% CI: 1.03–24.54, respectively). The ORs of CAS in both women and men with the highest hs-CRP tertile (>3 mg/L) reduced from 4.41 to 1.45 and 2.98 to 1.52, respectively, if they had diabetes mellitus, and from 9.68 to 2.43 and 2.60 to 1.75, respectively, if they had hypertension. Hypertension had a more negative effect on CAS development in diabetic than non-diabetic women, which was not observed in men. The highest hs-CRP tertile was an independent predictor of adverse outcomes. Patients with the highest hs-CRP tertile had more coronary events than patients with the lowest hs-CRP tertitle (p = 0.021, log-rank test).

Conclusions

Diabetes mellitus contributes to CAS development in men with low hs-CRP levels, but not in women. There are negative effects of diabetes mellitus and hypertension on CAS development in patients with high hs-CRP levels and especially in women. Elevated hs-CRP level independently predicts adverse outcomes.     

高原训练中运动员腹泻发生状况及肠道菌群的变化

目的:通过实地调研考察高原训练中运动员腹泻发生率,并采集运动员粪便样品,研究高原训练过程中运动员肠道菌群变化。方法:赴多巴国家高原训练基地调研在训运动员胃肠道反应,统计腹泻发生率及发生的时间特点。分别在运动员进驻高原前和高原训练过程中采集粪便样品,进行粪便常规检测、提取全基因组DNA,质检合格样品采用高通量测序的手段进行微生物多样性分析。结果:1)高原训练期间运动员腹泻发生率为46.7%,所有腹泻案例持续时间均10天,其中74.1%持续时间5天。2)腹泻案例发生主要集中在两个时间段,分别是进入高原后的第1-3天(占总腹泻案例数的35.7%)及进入高原后的第7-10天(占总腹泻案例数的46.4%),至进入高原后的第12天不再有新增腹泻案例出现。3)运动员进驻高原前后微生物多样性无显著差异。4)相较与平原时,运动员肠道菌群拟杆菌门先上升后恢复,厚壁菌门先下降后恢复。结论:1)高原训练中运动员多发腹泻,腹泻案例呈现出两个爆发高峰。2)运动员进驻高原后肠道菌群结构发生改变,表现为拟杆菌门占比上升、厚壁菌门占比下降。随着微生物多样性分析技术的普及,针对性补充有益菌保障运动员平稳度过高原习服期,有助于降低高原训练期间腹泻发生率。     

SSB蛋白的高效表达及其与ssDNA的相互作用

大肠杆菌单链结合蛋白SSB在DNA复制、重组和修复中起着重要作用。为研究单链结合蛋白SSB的体外生物功能构建了融合蛋白SSB的表达载体并使其高效表达及易于纯化。ssb基因片段是以E.coli K-12基因组为模板经PCR扩增获得,并通过基因的体外拼接成功构建了表达载体pQE30-ssb。重组菌株M15/ pQE30-ssb经过IPTG的诱导表达了蛋白SSB。收集菌体细胞、超声波破碎后离心取上清进行SDS-PAGE分析,结果表明有一与预期分子量（20.6 kD）相应的诱导表达条带出现,其表达量约占全细胞蛋白的30％且以可溶形式存在。利用固定化金属离子（Ni2+）配体亲和层析柱纯化融合蛋白SSB,其纯度达到90％。通过凝胶层析和等离子共振技术对SSB的生物功能进行了系统研究分析。结果表明,SSB蛋白以四聚体形式与单链DNA分子结合,其亲和力常数（KD）为4.79×10-7 M。