High energy phosphate compounds and mitochondrial function in ischemic myocardium of swine with advanced coronary atherosclerosis

High energy compounds (adenosine triphosphate and creatine phosphate), lactate and mitochondrial function and morphology were investigated in swine suffering from persistent myocardial ischemia. The myocardial ischemia was secondary to severe diffuse coronary artery atherosclerosis induced by hypercholesterolemia enhanced by X-irradiation to the heart.In the ischemic myocardia, the high energy phosphate compounds were decreased up to 50% and lactate was increased threefold. The ischemia apparently had also damaged myocardial mitochondria; QO₂ and ACR were lower in mitochondrial preparations from the ischemic tissue. In addition, electron microscopy showed more swollen and broken forms in mitochondria preparations from the ischemic myocardium. Hypercholesterolemia alone or irradiation alone to other groups of swine did not induce alterations in QO₂ or ACR, although the percentage recovery of mitochondria was decreased by X-irradiation to the heart.We cannot yet relate the findings in this study to the ventricular fibrillation and sudden death that these swine are prone to develop. A possibility that might be investigated is that the decrease in high energy compounds impairs function of ion transport systems (e.g. Na-K-ATPase). The resultant disturbances in ion transport may enhance the development of fibrillation. Despite the abnormalities of mitochondria in the myocardia of the ischemic swine, there were no manifestations of congestive heart failure in this group.     

Biochemistry tests in hospitalized COVID-19 patients: Experience from a Canadian tertiary care centre

BackgroundCoronavirus Disease 2019 (COVID-19) has variable clinical presentation, from asymptomatic to severe disease leading to death. Biochemical markers may help with management and prognostication of COVID-19 patients; however, their utility is still under investigation.MethodsA retrospective study was conducted to evaluate alanine aminotransferase, C-reactive protein (CRP), ferritin, lactate, and high sensitivity troponin T (TnT) levels in 67 patients who were admitted to a Canadian tertiary care centre for management of COVID-19. Logistic, cause-specific Cox proportional-hazards, and accelerated failure time regression modelling were performed to assess the associations of initial analyte concentrations with in-hospital death and length of stay in hospital; joint modelling was performed to assess the associations of the concentrations over the course of the hospital stay with in-hospital death.ResultsInitial TnT and CRP concentrations were associated with length of stay in hospital. Eighteen patients died (27%), and the median initial TnT concentration was higher in patients who died (55 ng/L) than those who lived (16 ng/L; P < 0.0001). There were no survivors with an initial TnT concentration > 64 ng/L. While the initial TnT concentration was predictive of death, later measurements were not. Only CRP had prognostic value with both the initial and subsequent measurements: a 20% increase in the initial CRP concentration was associated with a 14% (95% confidence interval (CI): 1–29%) increase in the odds of death, and the hazard of death increased 14% (95% CI: 5–25%) for each 20% increase in the current CRP value. While the initial lactate concentration was not predictive of death, subsequent measurements were.ConclusionCRP, lactate and TnT were associated with poorer outcomes and appear to be useful biochemical markers for monitoring COVID-19 patients.     

贵州省江口县土家族葡萄糖-6-磷酸脱氢酶基因突变分析

目的 了解贵州省江口县土家族葡萄糖-6-磷酸脱氢酶（G6PD）缺陷症的基因频率、基因突变类型特点及分布特征，从分子水平揭示G6PD基因多态性。方法 采集世居当地土家族男性血液样本227例，用四氮唑蓝（NBT）纸片定性法及G6PD／6PGD比值法做G6PD缺陷症筛查。确诊者用错配引物介导的聚合酶链反应／限制性内切酶酶切分析法（PCR-RE）进行中国人常见9种G6PD基因突变型分析，突变特异性扩增系统法（ARMS）验证其中3种突变。结果227名土家族男性中检出17例G6PD缺陷者，总检出率7．49％，G6PD缺陷症基因频率0．0749。基因分析检出cDNA1388（G→A）12例，在G6PD缺陷者中的基因频率为0．706，未知突变5例，基因频率为0．294。结论 G6PD缺陷症在贵州土家族人群有着较高的基因频率，其主要突变类型为G6PD基因cDNA1388（G→A）。     

Oxidation of palmitate and lactate by beating myocytes isolated from adult dog heart.

Myocytes were isolated from hearts of adult dogs by repeated digestion with collagenase and hyaluronidase in Ca²⁺-free phosphate buffer followed by centrifugation in the presence of Ficoll. The isolated myocytes were free of other tissue elements and were contracting autorhythmically. The oxidation of palmitate and lactate were studied by incubating cell preparation with [1-¹⁴C]palmitate or [U-¹⁴C]lactate either in the presence or absence of CaCl₂ for 30 min at 37°C. [¹⁴C]O₂ was collected by KOH-soaked filter paper. Cardiac myocytes oxidized 0.1 to 0.18 nmol/mg protein min of palmitate and 1.5 to 2.2 nmol/mg protein min of lactate. The oxidation was linear for 75 min. Maximal rate of oxidation was obtained at substrate concentrations of 0.2 mm palmitate or 5.0 mm lactate. Adenine or pyridine nucleotides had no effect on the oxidation of these substrates. Palmitate oxidation was enhanced by carnitine and also by an increase in the molar ratio of palmitate/albumin, but was depressed (15 to 50%) by CaCl₂ (0.025 to 1.0 mm). CaCl₂ (0.05 to 1.0 mm) increased the rate of lactate oxidation by 50 to 68%. Lactate oxidation was also enhanced (68 to 87%) in the presence of palmitate (0.4 to 0.8 mm). These findings demonstrate the suitability of isolated adult heart myocytes for the study of cardiac metabolism.     

日本血吸虫乳酸脱氢酶(SjLDH)结构与功能的生物信息学分析

目的 应用生物信息学分析软件预测日本血吸虫乳酸脱氢酶（SjLDH）氨基酸序列的结构与功能。 方法 应用NCBI、Expasy等在线生物信息学网站及Vector NTI、PCgene等软件包分析SjLDH与其他物种的同源序列，进行多序列同源比对，分析相同的保守位点及催化活性位点，构建分子进化树；预测二级结构、拓扑结构；同源模建预测三级结构；预测主要抗原表位等。 结果 SjLDH与其他物种的同源序列含相同的保守位点及催化活性位点，与华支睾吸虫LDH（CsLDH）同源性最高为75％，与阴道毛滴虫LDH（TvLDH）同源性最低为17%，与人LDH（HsLDH-A，-B，-C）的同源性为58%~60％； SjLDH与果蝇（DmLDH）的进化距离较秀丽隐杆线虫（CeLDH）为近，3种人LDH中与HsLDH-B、-C的进化距离较HsLDH-A为近；该蛋白具有3个跨膜区域，3个高亲水性区域，主要的线性表位98aa~106aa位于膜外，与原虫LDH相同区域差异显著，而与其他LDH有1~3个氨基酸的差异，关键催化位点之一及底物丙酮酸结合区域位于该区域，蛋白质同源模建分析表明该区域位于蛋白表面形成环状结构，3个关键催化位点位于该区域或在其附近。 结论 生物信息学预测结果提示LDH是研究物种分子进化理想的分子；SjLDH可能是免疫诊断、药物作用及疫苗潜在的靶分子。     

潜在致病性的弗氏枸橼酸杆菌的筛查

目的 筛查具有潜在致病性的弗氏枸橼酸杆菌。方法 对从河南省睢县分离到的36株弗氏枸橼酸杆菌进行黏附HEp-2细胞的检测,以及与HEp-2细胞(MOI: 100)作用10 h后的乳酸脱氢酶(LDH)释放情况分析。同时比较弗氏枸橼酸杆菌CF74(Citrobacter freundii 74)、CF72(Citrobacter freundii 72)、肠聚集性大肠埃希菌(Enteroaggregative E. coli,EAEC)、肠致病性大肠埃希菌(Enteropathogenic E. coli,EPEC)2348/69和HB101的黏附和细胞毒性差异。结果 16株弗氏枸橼酸杆菌几乎没有黏附性,黏附指数1;18株弗氏枸橼酸杆菌具有中等强度的黏附性,黏附指数100;2株弗氏枸橼酸杆菌CF74和CF65(Citrobacter freundii 65)具有强的黏附性。与HEp-2细胞作用10 h后,除了CF74(24.4%),其余的35株弗氏枸橼酸杆菌具有低的LDH释放量,LDH释放量与阴性对照HB101(5.02%)相似。说明除了CF74,其余的弗氏枸橼酸杆菌不具有细胞毒性。CF74具有和EAEC042一样的聚集性黏附类型,并且 CF74引起的LDH释放率明显高于CF72、2348/69和HB101(P0.01)而低于EAEC17-2。结论 作为潜在的致病菌,CF74具有强的黏附性和细胞毒性。     

Serum bilirubin value predicts hospital admission in carbon monoxide-poisoned patients. Active player or simple bystander?

OBJECTIVES:

Although carbon monoxide poisoning is a major medical emergency, the armamentarium of recognized prognostic biomarkers displays unsatisfactory diagnostic performance for predicting cumulative endpoints.

METHODS:

We performed a retrospective and observational study to identify all patients admitted for carbon monoxide poisoning during a 2-year period. Complete demographical and clinical information, along with the laboratory data regarding arterial carboxyhemoglobin, hemoglobin, blood lactate and total serum bilirubin, was retrieved.

RESULTS:

The study population consisted of 38 poisoned patients (23 females and 15 males; mean age 39±21 years). Compared with discharged subjects, hospitalized patients displayed significantly higher values for blood lactate and total serum bilirubin, whereas arterial carboxyhemoglobin and hemoglobin did not differ. In a univariate analysis, hospitalization was significantly associated with blood lactate and total serum bilirubin, but not with age, sex, hemoglobin or carboxyhemoglobin. The diagnostic performance obtained after combining the blood lactate and total serum bilirubin results (area under the curve, 0.90; 95% CI, 0.81-0.99; p<0.001) was better than that obtained for either parameter alone.

CONCLUSION:

Although it remains unclear whether total serum bilirubin acts as an active player or a bystander, we conclude that the systematic assessment of bilirubin may, alongside lactate levels, provide useful information for clinical decision making regarding carbon monoxide poisoning.     

血乳酸浓度和D－二聚体联合测定对急诊创伤性休克患者预后评估研究

目的：探讨血乳酸浓度和D－二聚体联合测定对急诊创伤性休克患者预后评估的价值。方法回顾性分析98例急诊创伤性休克患者的临床资料,其中77例经ICU治疗后存活并转出（存活组）,21例患者经ICU急救后死亡（死亡组）。观察两组患者血乳酸浓度和D－二聚体水平。结果存活组入院时、6 h、12 h、24 h血乳酸水平、D－二聚体水平、急性心理学与慢性健康状况Ⅱ（ APACHEⅡ）评分均低于死亡组（ P＜0.05）。结论联合测定血乳酸浓度、D－二聚体及APACHEⅡ评分,能准确评价病情及预后,为临床救治急性创伤性休克患者提供参考。     

Glucose metabolism transporters and epilepsy: Only GLUT1 has an established role

The availability of glucose, and its glycolytic product lactate, for cerebral energy metabolism is regulated by specific brain transporters. Inadequate energy delivery leads to neurologic impairment. Haploinsufficiency of the glucose transporter GLUT1 causes a characteristic early onset encephalopathy, and has recently emerged as an important cause of a variety of childhood or later‐onset generalized epilepsies and paroxysmal exercise‐induced dyskinesia. We explored whether mutations in the genes encoding the other major glucose (GLUT3) or lactate (MCT1/2/3/4) transporters involved in cerebral energy metabolism also cause generalized epilepsies. A cohort of 119 cases with myoclonic astatic epilepsy or early onset absence epilepsy was screened for nucleotide variants in these five candidate genes. No epilepsy‐causing mutations were identified, indicating that of the major energetic fuel transporters in the brain, only GLUT1 is clearly associated with generalized epilepsy.