‘Ammonia,lactate and blood gases – A user's guide’

Basic biochemical tests are frequently obtained in acutely unwell neonates and children, as well as in some elective situations. Correct interpretation can be invaluable in identifying rare inherited primary metabolic disorders, but secondary causes of hyperammonaemia, elevated blood lactate or blood gas derangement are more common and require appropriate treatment of the underlying cause. This Personal Practice guide provides an overview of these tests and their interpretation.     

Association of dietary acid-base load and psychological disorders among Iranian women: A cross-sectional study

Metabolic acidosis, which can be affected by dietary acid-base load, seems to be associated with psychological disorders through different pathways. Given limited evidence on dietary acid-base load, we aimed to examine the association of dietary acid-base load with psychological disorders in Iranian women. This cross-sectional study was performed on 447 female subjects (20–50 years old). Dietary intake was assessed using a valid food frequency questionnaire for Iran. Dietary acid-base load was calculated through different indices including potential renal acid load (PRAL), net endogenous acid production (NEAP), and dietary acid load (DAL). To assess psychological disorders, an Iranian validated version of depression, anxiety, and stress scale (DASS-21) was used. The mean value of PRAL, NEAP, and DAL were -8.87mEq/da, 37.94mEq/day, and 30.77mEq/day, respectively. Considering a wide range of confounding variables, compared with the first tertile, a significant positive association was observed between dietary acid-base load and depression (OR_PRAL: 3.63; 95 %CI:1.97, 6.71; P_trend = 0.0001) (OR_NEAP:3.42; 95 %CI: 1.87, 6.23; P_trend = 0.0001) (OR_DAL: 3.02; 95 %CI: 1.64, 5.58; P_trend = 0.0001). Women in the high dietary acid-base load category had higher anxiety (OR_PRAL: 3.31; 95 %CI: 1.81, 6.06; P_trend = 0.0001) (OR_NEAP:3.47; 95 %CI: 1.90, 6.33; P_trend = 0.0001) (OR_DAL: 3.25; 95 %CI: 1.76, 5.98; P_trend = 0.0001). Moreover, there was a strong positive relationship between dietary acid-base load and psychologicaldistress (OR_PRAL: 3.79; 95 %CI: 2.09, 6.90; P_trend = 0.0001) (OR_NEAP: 3.67; 95 %CI: 2.04, 6.58; P_trend = 0.0001) (OR_DAL: 3.00; 95 %CI: 1.66, 5.43; P_trend = 0.0001). Women with higher dietary acid-base load score had greater odds for depression, anxiety, and psychological distress compared to lower ones.     

高渗羟乙基淀粉(200/0.5)氯化钠注射液用于择期颅脑手术麻醉效果探讨

目的 探讨高渗羟乙基淀粉(200/0.5)氯化钠注射液用于择期颅脑手术麻醉对患者血流动力学、电解质酸碱平衡及降低颅内压效果的影响.方法 选取行择期胶质瘤切除手术患者120例,以随机抽样方法分为对照组(60例)和高渗组(60例);分别给予常规羟乙基淀粉和高渗羟乙基淀粉(200/0.5)静脉输注,比较两组患者不同时间点心率(HR),平均动脉压(MAP),中心静脉压(CVP),Na+、K+、Ca2+、pH及颅内压(ICP)等指标水平.结果 两组患者T2、T3及T4时间点HR和CVP指标均较T0时间点明显提高,差异有统计学意义(P＜0.05);两组患者T3和T4时间点MAP指标均较T0时间点显著降低,差异有统计学意义(P＜0.05);而高渗组患者T4时间点HR和MAP指标水平均明显优于对照组,差异有统计学意义(P＜0.05);两组患者T1、T2、T3及T4时间点Na+和K+指标水平与T0时间点比较差异有统计学意义(P＜0.05);两组患者T2、T3及T4时间点ICP水平较T0时间点均显著降低,差异有统计学意义(P＜0.05);高渗组患者T4时间点ICP水平显著低于对照组,差异有统计学意义(P＜0.05).结论 高渗羟乙基淀粉(200/0.5)氯化钠注射液用于行颅脑外科手术治疗患者可有效稳定血流动力学,纠正电解质酸碱平衡平衡紊乱,并抑制颅内压升高.     

High systemic HCO 3 − and topical 16,16-dimethyl-PGE2 protect gastric mucosa against luminal acid by enhancing its preepithelial buffer capacity

Systemic metabolic alkalosis and topical prostaglandins protect the gastric mucosa against luminal acid. This study investigates whether this protection is mediated by increased epithelial HCO ₃ ^– secretion with resultant alkalization of the preepithelial mucus-HCO ₃ ^– buffer layer. Surface pH of chamberedex vivo rat gastric epithelium was measured with liquid sensor pH microelectrodes during luminal perfusion of increasing acidities (0, 10, 30, 50, 100 mM HCl). The experimental groups were: (1) control, (2) topical 16,16-dimethyl-PGE₂ treatment, (3) high-HCO ₃ ^– metabolic alkalosis, and (4) low-HCO ₃ ^– respiratory alkalosis. The gastric mucosa of PGE₂-treated and high-HCO ₃ ^– alkalotic rats tolerated significantly better luminal acid than that of controls, but the tolerance of low-HCO ₃ ^– alkalotic rats was significantly impaired. There was a significant correlation between arterial HCO ₃ ^– concentration (but not arterial pH) and surface pH (r=0.81,P<0.01). This suggests that the protective actions of systemic high-HCO ₃ ^– alkalosis and topical-PGE₂ treatment in the gastric mucosa against luminal acid are, at least in part, mediated by enhanced buffer capacity of the preepithelial mucus-HCO ₃ ^– layer.This study is supported by grants from the Medical Research Council of the Academy of Finland and Sigrid Juselius Foundation, Helsinki, Finland and Orion Research Council, Espoo, Finland.     

Overcoming the Challenges of Low Drug Solubility in the Intravenous Formulation of Solithromycin

Solithromycin is a fluoro-ketolide (a fourth-generation macrolide) antibiotic that has been undergoing clinical trials for the treatment of community-acquired bacterial pneumonia. In this study, development of the tri-amino acid–buffered solithromycin intravenous (IV) formulation was performed to minimize the occurrence of infusion-associated local adverse events (infusion-site pain or phlebitis) observed in patients who received the tartaric acid–buffered IV formulation with a lower buffered capacity during phase I clinical trials. Development of the tri-amino acids–buffered solithromycin IV formulation was achieved using a dynamic in vitro precipitation model. Computational modeling also supports the superiority of the amino acid-buffered formulation over the tartaric aid–buffered formulation.     

Accurate prediction of hypoxic-ischaemic encephalopathy at delivery: a cohort study

Objective: Hypoxic-ischaemic encephalopathy (HIE) is a major acute neurologic manifestation of perinatal asphyxia associated with significant mortality and morbidity. The study aimed to develop a simple, accurate method of predicting HIE at delivery. Methods: Between January 2003 and December 2009, all HIE cases were identified from the 38,404 deliveries at a single tertiary centre. Receiver operating curve (ROC) analysis and multivariate logistic regression assessed the ability of clinical and biochemical assessments to predict HIE. Results: Sixty neonates met the HIE criteria: 39 were moderate-severe HIE. Univariate analyses identified clinical neonatal markers (Apgar scores and neonatal resuscitation level) to be better HIE predictors than biochemical markers (umbilical artery pH, base excess and lactate values). Multivariable models using two to four predictors had areas under ROC curves up to 0.98, sensitivities up to 93% and specificities up to 99%. For moderate-severe HIE, the most effective predictor was neonatal resuscitation level and arterial lactate (ROC 0.98, sensitivity 85%, specificity 99%). Conclusion: The combination of umbilical arterial lactate and neonatal resuscitation level provides a rapid and accurate method of predicting moderate-severe HIE that can identify neonates at birth that may benefit from tertiary care and neuroprotective therapies.     

老年人肾脏酸化功能的变化（附313例健康人检测结果分析）

目的观察老年人肾小管酸化功能的变化。方法通过对８５例老年人、１１７例老年前期与１１１例青中年健康者测定尿ｐＨ、碳酸氢根、可滴定酸、铵及净酸排泄量，进行对照分析。结果随年龄增长，尿中碳酸氢根排泄量增加，可滴定酸、铵及净酸排泄量减少。结论老年随年龄增长，肾小管泌氢功能减退。     

Simultaneous double-isotope autoradiographic measurement of local cerebral glucose metabolic rate and acid-base status in rat brain

We developed a double-isotope autoradiographic method for the simultaneous measurement of the local cerebral metabolic rate for glucose (1CMRG) and index of regional acid-base status (rABI) in single brain slices using [2-¹⁴C]deoxy-D-glucose (DG) and 5,5-dimethyl-[2-¹⁴C]oxazolidine-2,4, dione (DMO). After iv isotope administration, paper chromatography separates plasma DMO from DG activity using a methanol-methylene chloride solvent system. Initial tissue autoradiograms depict regional DMO plus DG and DG metabolite distribution. After 14 days in a well-ventilated hood, 97.5 ±0.5% of all DMO is lost from tissue sections by sublimation, and a second autoradiogram depicts DG plus DG metabolite distribution. Retention of brain lipids does not alter beta-particle self-absorption, avoiding problems associated with isotope extraction with solvents. Autoradiograms are digitized and converted to isotope-content images. The second autoradiogram is used for lCMRG computation. After subtracting the second regional isotope-content value from the first, the DMO content is obtained and used to compute rABI. Application of this method to normal animals yields expected values for lCMRG and rABI. This method is amenable to whole-slice digitization and creation of functional images of lCMRG and ABI followed by pixel-by-pixel correlations of the two variables, making this a potentially valuable tool for the investigation of the relationships between glucose metabolism and brain acid-base balance.     

排钾-保钾结合排酸-保酸利尿方案对肺心病的探讨

目的　评价排钾 -保钾结合排酸 -保酸利尿方案对肺源性心脏病的优越性。方法　 191例肺源性心脏病例随机分为 A组 (42例 )、B组 (6 3例 )、C组 (86例 )。A组予呋塞米 2 0 mg(或氢氯噻嗪 5 0 mg) ,每日一次 ;B组予呋塞米 2 0 mg(或氢氯噻嗪 5 0 mg)、螺内酯 4 0 mg,每日各一次 ;C组予呋塞米 2 0 mg(或氢氯噻 5 0 mg)、螺内酯 4 0mg、乙酰唑胺 2 5 0 mg,每日各一次。对比三组治疗前后 K 、Na 、Cl- 、p H值、HCO3- 、SBE、Pa CO2 等指标的变化及肺性脑病的发生情况。结果　治疗 7日后 ,A组 K 、Na 、Cl 均显著降低 (P<0 .0 1) ,p H、HCO- 3、SBE和 Pa CO2 均显著升高 (P<0 .0 1) ;B组 Na 、Cl- 均显著降低 (P<0 .0 1) ,p H、HCO3- 、SBE和 Pa CO2 均显著升高 (P<0 .0 1) ,而K 变化不显著 (P>0 .0 5 ) ;C组虽 Na 仍有显著降低 (P<0 .0 5 ) ,但 K 、Cl- 、p H、HCO3- 、SBE、Pa CO2 变化均不显著 (P>0 .0 5 )。C组肺性脑病的发生率 (0 % )比 A组 (9.5 % )、B组 (12 .7% )显著减少 (P<0 .0 5～ 0 .0 1)。结论　排钾-保钾结合排酸 -保酸利尿方案对维持肺心病的电解质和酸碱平衡及预防肺性脑病的发生有明显优越性。     

危重病三重酸碱失衡发生率及预后分析

目的：了解危重病三重酸碱失衡(TABD)发生率及预后。方法：选择392例危重病患者为研究对象,检测其动脉血气分析值和血电解质,计算阴离子间隙、潜在HC03 -,根据酸碱失衡诊断标准,了解TABD的发生率,并分析其预后情况。结果：392例危重患者中TABD 42例(10.7％),≥60岁TABD发生率较高,TABD组年龄...