Interpreting HbA1c in Presence of Deficiency Anemias

HbA1c is used extensively for the diagnosis and management of diabetes mellitus. It constitutes 80% of glycated HbA1(Glycated haemoglobin(GHb)A), and depends upon blood glucose and RBC life span. RBC life span varies with anemia, leading to a consequent alteration in the HbA1c value irrespective of the circulating blood glucose concentration. But to the best of our knowledge no Hb cut offs have been derived for appropriate interpretation of HbA1c. The prevalence of anemia in Indian population is nearly 40% as per its definition by WHO—Hb < 12 g/dL in females and < 13 g/dL in males—with most cases attributable to nutritional deficiencies. Hence, we aimed to identify Hb cut-off for accurate interpretation of HbA_1c in presence of deficiency anemias. Partial correlation between random blood glucose (RBG) and HbA_1c was studied in 1312 subjects, 470 of whom had deficiency-related anemia]. The data was adjusted for age, sex and Hb. Partial correlation between RBG and HbA1c was highly significant (p < 0.0001) till Hb of 8.1 gm/dL. Significance reduced to p = 0.003 and p = 0.006 as the cut off of Hb reduced to 7.1 gm/dL and 5.0 gm/dL, respectively, but was not lost. Hence, caution in interpretation of HbA_1c is not required till an Hb of 5 g/dL.     

Automatic laboratory-based strategy to improve the diagnosis of type 2 diabetes in primary care

Introduction

To study the pre-design and success of a strategy based on the addition of hemoglobin A1c (HbA1c) in the blood samples of certain primary care patients to detect new cases of type 2 diabetes.

Materials and methods

In a first step, we retrospectively calculated the number of HbA1c that would have been measured in one year if HbA1c would have been processed, according to the guidelines of the American Diabetes Association (ADA). Based on those results we decided to prospectively measure HbA1c in every primary care patient above 45 years, with no HbA1c in the previous 3 years, and glucose concentration between 5.6-6.9 mmol/L, during an 18 months period. We calculated the number of HbA1c that were automatically added by the LIS based on our strategy, we evaluated the medical record of such subjects to confirm whether type 2 diabetes was finally confirmed, and we calculated the cost of our intervention.

Results

In a first stage, according to the guidelines, Hb1Ac should have been added to the blood samples of 13,085 patients, resulting in a cost of 14,973€. In the prospective study, the laboratory added Hb1Ac to 2092 patients, leading to an expense of 2393€. 314 patients had an HbA1c value ≥ 6.5% (48 mmol/mol). 82 were finally diagnosed as type 2 diabetes; 28 thanks to our strategy, with an individual cost of 85.4€; and 54 due to the request of HbA1c by the general practitioners (GPs), with a cost of 47.5€.

Conclusion

The automatic laboratory-based strategy detected patients with type 2 diabetes in primary care, at a cost of 85.4€ per new case.Key words: type 2 diabetes, HbA1c, diagnosis, preanalytical phase, test request appropriateness, costs, cost analysis     

Characterization of a Double Heterozygote HbE/β+ Thalassemia IVS 1-1 [G>T] in a Juvenile Diabetic

The present case report describes the molecular and proteomic based study of Hb variant HbE associated with β⁺ thalassemia IVS 1-1 G>T, in a juvenile diabetic patient. Given the ethnic origin and mobility of the variant hemoglobin at alkaline pH, HbE would be suspected. But hematologically and clinically abnormality being detected, HPLC and Electrophoresis not being able to characterize due to retention time and band being in region of HbA2, respectively, further characterization of hemoglobinopathy was made using MALDI and IVS 1-1 G>T being validated by reverse dot blot hybridization. Capillary electrophoresis was also employed in order to separate HbE and HbA2 bands. This case report being first of its kind, wherein a HbE/β⁺ thalassemia has been characterized using multiple techniques.     

Hemoglobin Hasharon and hemoglobin NYU in subjects of German origin

Determination of HbA1c values with high performance liquid chromatography (HPLC) occasionally reveals hemoglobin anomalies with no or minimal clinical evidence. We coincidentally detected two cases of Hb Hasharon, an alpha globin gene mutation, in two heterozygous patients and one case of Hb NYU, a delta globin gene mutation, in another patient. Both anomalies have not been described in subjects of German origin to date. Characterization was carried out with HPLC, hemoglobin electrophoresis, capillary zone electrophoresis, DNA sequencing, complete blood count and clinical chemical analysis.     

Glycosylated haemoglobin-a diagnostic tool in pregnant diabetics

Blood samples of 40 pregnant women were analysed for glycosylated haemoglobin (HbA1c) and blood sugar. The patients were followed up till delivery and their obstetric outcome was analysed in conjunction with the glycaemic profile and the level of glycosylated haemoglobin. Group I comprising the normal pregnant women showed a mean HbA1c of 6.23% at 20–40 weeks of gestation. In contrast the diabetic pregnant women (group II) at the same gestation demonstrated an HbA1c of 9.4%. Further group IIA of gestational diabetic women showed an HbA1c of 8.97% and group IIB comprising the overt diabetics had HbA1c of 9.86%. The mother who delivered a congenitally malformed child had an elevated HbA1c of 10.4% during pregnancy. Seven cases of macrosomia were reported and the mean HbA1c of their mothers at 20–40 weeks of gestation was found to be 9.91%. Six mothers delivered infants who developed respiratory distress syndrome (RDS) soon after birth and all these six had elevated HbA1c with a mean of 8.9%. Abortions were also associated with elevated HbA1c of 10.3% antenatally. One case of still birth was reported and the mother demonstrated an elevated glycosylated haemoglobin during pregnancy. An HbA1c of 10% or more was associated with abortion, still-birth, or congenitally malformed babies.     

Interaction of hemoglobin Grey Lynn (Vientiane) with a non-deletional α+-thalassemia in an adult Thai proband

Hemoglobin (Hb) Grey Lynn is a Hb variant caused by a substitution of Phe for Leu at position 91 of α1-globin chain, originally described in individual of unknown ethnic background. This article addresses the interaction of Hb Grey Lynn with a non-deletional α⁺-thalassemia found in Thailand, a hitherto un-described condition. The proband was adult Thai woman referred for investigation of mild anemia with Hb 90 g/L. Hb analyses using low pressure liquid chromatography raised a suspicion of abnormal Hb presence, which was failed to demonstrate by cellulose acetate electrophoresis and capillary electrophoresis. DNA sequencing identified a CTT (Leu) to TTT (Phe) mutation at codon 91 corresponding to the Hb Grey Lynn (Vientiane) [α91(FG3)Leu>Phe (α1) on α1-globin gene and a C deletion between codons 36 and 37 on α2-globin gene causing α⁺-thalassemia. As compared to those observed in a compound heterozygote for Hb Grey Lynn / α⁰-thalassemia reported previously, higher MCV (81.7 fL) and MCH (26.3 pg) values with a lower level of Hb Grey Lynn (19.7%) were observed in the proband. The normochromic normocytic anemia observed could be due to the interaction of Hb Grey Lynn with α⁺-thalassemia. The two mutations could be identified using PCR-RFLP and allele-specific PCR assays developed.     

Diagnostic Dilemma of HbA1c Detection in Presence of a Hemoglobinopathy: A Case Report

We report a case of a diabetic, heterozygote with near normal hematology, marginally low level of hemoglobin A₂(HbA₂) having an increased level of hemoglobin F(HbF) that was pancellularly distributed among the red cells. BioRad DiaSTAT measurements gave a high glycated hemoglobin A1c(HbA1c) of 31.5% and the BioRad Variant analyzer recorded an HbA1c value which was very low, in discordance with the detected blood glucose levels. Flow cytometry and polymerization chain reaction (PCR) based studies were carried out which revealed the case to be that of the common hereditary persistence of fetal hemoglobin (HPFH)-3, an Asian Indian mutation. Fructosamine estimation and HbA1c by Boronate affinity chromatography were able to resolve the discordant value detected and was able to confirm the diabetes status. The case would have been a diagnostic dilemma, if reported without correlation.     

Detection of hemoglobin E in Endhra Pradesh: Mutational analysis using polymerase chain reaction and restriction enzyme Mnl 1

Hemoglobin E (beta-26^{Glutamic acid→Lysine}) is the second most prevalent hemoglobin variant in the world. 293 blood samples from cases referred from several hospitals in the region of Andhra Pradesh were screened for the detection of hemoglobinopathies. Four samples were found to be in heterozygous state for Hb E condition. Mutation in two of these heterozygotes was analysed using a 722 base pair (bp) amplified DNA fragment from beta-globin gene and restriction enzyme Mnl 1. A 232bp DNA fragment was found to be associated with the Hb E mutation.     

湖南省耕地经营协调度时空演变

揭示区域耕地经营格局特征有助于从区域层面解读耕地经营模式特点,切实有效提出区域耕地利用转型的重点和发展方向。本研究基于“集约-规模-产能”三要素提出耕地经营协调度评价模型,并借助协调度函数和探索性空间数据分析方法揭示湖南省县域耕地经营格局演变特征。结果表明：①1990—2014年间,湖南省县域耕地经营协调水平整体较高,且空间格局差异明显：“长株潭”丘陵区集约指数较高,洞庭湖平原区规模指数较高,主要市辖区及其周边县域产能指数较高;②受不同地理区位和社会经济影响,湖南省县域耕地经营要素时空集聚特征存在明显差异:空间维度上,耕地经营协调度由“大集聚”向“小集聚”分布转变;时间维度上,规模指数自相关性较强且分布较集中,产能指数自相关性较弱且分布较分散;③从“投入-规模-产出”过程看,平原区呈现“高-高-高”特征,丘陵区表现“高-低-低”特征,山地区则为“低-低-低”特征。结合耕地经营格局时空演化特征成因,建议湖南各县域因地制宜地采用以粮食作物为主的集约经营模式,以经济作物为主的复合经营模式和特色作物经营模式。     

Characterization of a hemoglobin variant: HbQ-India / IVS 1-1 [G>T]-β-thalassemia

Hemoglobin Q- India (alpha) 64 Asp → His is an alpha chain variant which is generally found in heterozygous state and presents normal hematological blood picture. Here we report a rare case of HbQ-India with a thalassemic phenotype that has been analyzed using a combination of mass spectrometry, gene sequencing and PCR analysis. This combined analyses revealed the HbQ variant to be associated with a beta chain mutation, IVS 1-1 [G>T]. Though HbQ has earlier been reported with thalassemic trait using different techniques, this is the first report of a compound α and β chain Hb heterozygous mutant involving HbQ and IVS1-1 being validated using Mass Spectrometry and Reverse dot blot hybridization.     

基于最坏情景理论的连云港土地利用变化情景模拟

预测和模拟土地利用情景变化对于进一步评估土地利用变化的生态环境影响以及优化土地利用规划方案具有重要作用。本文基于最坏情景理论,以基于人工神经网络（ANN）和元胞自动机（CA）的FLUS模型为支持,模拟了最坏情景模式（WSB）和非最坏情景模式下（NWSB）的沿海城市连云港2020年土地利用变化。结果表明：①基于生态因子耐受度测算得出研究区最坏情景区域共计489.67 km²,该区域主要包括连云港中部云台山国家自然保护区内海拔较高、坡度较大、分布大量天然林地的区域以及重要的河流湖泊水库等生态水体;②两种情景模式下城镇用地均有较大程度的扩张,在WSB情景下城镇用地扩张避开了最坏情景区域;③由于村庄的存量利用率较高,因此在WSB模式下对于耕地的占用相对较小,表明该模式下可在一定程度上减少村庄建设对耕地的占用,从而提高了存量建设用地的使用效率;④由于最坏情景区域的约束和限制转化作用,城镇用地扩张在WSB模式下不得不占用更多的耕地,从而对耕地保护工作提出了更高的要求。基于最坏情景理论进行土地利用变化模拟对于生态环境保护及区域可持续发展具有重要的支撑作用,因而既可为区域土地规划和管理提供支持,也可为其他地区土地利用模拟提供参考和借鉴。     

Survey on reporting of epithelial cells in urine sediment as part of external quality assessment programs in Brazilian laboratories

IntroductionEpithelial cells (ECs) are structures regularly observed during urine microscopy analysis. The correct identification of EC subtypes can be useful since renal tubular epithelial cells (RTECs) are clinically relevant. We investigate the urinary ECs report and the judgement of its clinical importance by Brazilian laboratories.Materials and methodsA survey with four questions was made available to participants of the Urinalysis External Quality Assessment Program (EQAP) from Controllab. Laboratories composed 3 groups: (1) differentiating ECs subtypes: “squamous”, “transitional” and “RTECs”; (2) differentiating ECs subtypes: “squamous” or “non-squamous” cells; (3) without ECs subtype identification. Participants did not necessarily answer to all questions and the answers were evaluated both within the same laboratory’s category and within different categories of laboratories.ResultsA total of 1336 (94%) laboratories answered the survey; Group 1, 119/140 (85%) reported that ECs differentiation is important to the physician and 62% want to be evaluated by EQAP, while in Group 3, 455/1110 (41%) reported it is useful to them, however only 25% want be evaluated by EQAP. Group 2 laboratories 37/51 (73%) reported that the information is important, but only 13/52 (25%) are interested in an EQAP with differentiation of the 3 ECs subtypes.ConclusionMost of the laboratories do not differentiate ECs in the three subtypes, despite the clinical importance of RTECs. Education of laboratory staff about the clinical significance of urinary particles should be considered a key priority.     

基于感知价值理论的移民安置区农户土地投入行为研究

非自愿性移民的农业安置模式正面临安置效果和安置效率的“双低困局”,传统“以土为本、以农为主”的移民安置方式亟待改革创新。农业安置模式的现实困境,不仅体现为人地关系的局部紧张,同时也表现为农户土地投入意愿与行为的变化。本文基于感知价值理论,利用多群组SEM的分析方法,对湖南渫水皂市水利枢纽工程移民安置区原住民与移民两类农户主体的土地投入行为进行了实证研究。结果发现：①移民安置区农户的土地投入行为决策是经济、心理和情境因素共同作用的结果,其行为逻辑符合“认知层次→认知权衡→感知价值→行为意愿→行为响应”的路径范式;②原住民与移民两类农户主体的土地投入行为决策影响因素的效应值存在显著差异,原住民农户的土地投入行为是对土地投入“利弊权衡”后的“客观理性”决策,而移民农户的土地投入行为则更多的表现出“风险厌恶”的“主观理性”倾向。     

Dyslipidemia Associated with Poor Glycemic Control in Type 2 Diabetes Mellitus and the Protective Effect of Metformin Supplementation

The nature of the dyslipidemia associated with diabetes mellitus is complex and is the major risk factor for atherosclerosis and coronary artery disease. Aim of this study was to assess the effect of glycemic control, achieved by metformin, glibenclamide and insulin, on lipid profile in type 2 diabetic patients. One hundred and sixty-five type 2 diabetes mellitus patients were classified into good glycemic control (Group I) and poor glycemic control (Group II) on the basis of their blood HbA1c values. The Group II was characterized with high serum triglyceride (190.46 ± 15.20 mg/dl), total cholesterol (175.3 ± 6.31 mg/dl) as well as high LDL-cholesterol (109.0 ± 5.88 mg/dl). Significant correlations were evident between HbA1c and dyslipidemia, particularly serum TG (r = 0.28, P < 0.05), and between HbA1c and total cholesterol (r = 0.310, P < 0.05). Better glycemic control and improved dyslipidemia were observed in patients on combination therapy of metformin plus glibenclamide.     

Application of sigma metrics for the assessment of quality assurance using the MQ-2000 PT HbA1c analyzer

Introduction

Glycosylated hemoglobin (HbA1c) concentrations measured in clinical chemistry laboratories show large differences between their interlaboratory reported values. Laboratory measurements of quality performance should be based on quantitative data. The sigma metrics model provides an objective method for the assessment of current HbA1c assays and is useful in quality management planning. The aim of our study was to evaluate the analytical performance of the MQ-2000 PT HbA1c analyzer test results in the context of our operating conditions on the sigma scale.

Materials and methods

The coefficient of variation was determined from the calculated mean and standard deviation evaluated from internal quality control (QC) (N = 168 days) (Shanghai Huachen Biological Reagent Co. Ltd, China) data, and records of external quality data (KBUDEK, İstanbul, Turkey) measured in the period from May to November 2013 were used to determine the bias. The resulting data and total allowable error rate (TEA = 10%) from the Clinical Laboratory Improvement Amendments of 1988 (CLIA’88) were used to calculate the sigma level.

Results

The calculated coefficient of variations (CVs) at the two levels, normal (QC1 = 36.6 ± 2.38 mmol/mol) and pathological (QC2 = 84.7 ± 2.68 mmol/mol), were 6.5% and 3.1%, respectively. The average bias between the external QC and MQ-2000 PT during the study period was 4.3%. The calculated average sigma value was 1.19.

Conclusions

The MQ-2000 PT HbA1c is a new analyser in the market; there is need for improvement and the method should be controlled with greater attention to ensure quality.Key words: diabetes mellitus, hemoglobin A1c protein, human, chromatography, high pressure liquid chromatography     

1990年以来卢旺达森林转型路径及趋势模拟

社会经济发展过程中一个国家（地区）森林面积由减少转为增加的“森林转型“内在驱动机制,是资源环境研究关注的热点。以4期卢旺达土地覆盖数据为主要信息源,分析1990—2015年该地区森林变化的趋势和时空特征。结合社会经济数据,借助森林转型的路径分析法,探究卢旺达森林面积变化的影响因素及其所遵循的转型路径。在此基础上,利用PLUS模型对卢旺达2030年的森林空间动态分布进行模拟预测,对如何继续保持良好转型态势提出相关建议。结果表明：①卢旺达森林面积在2010年开始出现净增长,由2010年的197383.2 hm²增加到2015年的213087.8 hm²,年增加率0.8%;②国家公园和保护区是森林增长主要地区,且主要来源于稀树草原和耕地,分别占森林净增加总面积的87.8%和8.8%;③转型的内在驱动机制主要是国家政策引导下发生的“国家森林政策路径”和“森林稀缺路径”,全球化路径体现在植树技术与资金支持;④对卢旺达2030年森林模拟预测显示,森林转型仍将继续,预计到2030年森林面积将净增加34065.2 hm²。为进一步提高研究区森林覆盖率,卢旺达政府部门应改善森林恢复的薄弱环节,加快农业集约化推广;通过为农村社区创造场外就业机会,引导经济和就业发生转型,从而推动基于“经济发展路径”与“农村集约化路径”的森林增加。     

Evaluation of preanalytical and postanalytical phases in clinical biochemistry laboratory according to IFCC laboratory errors and patient safety specifications

IntroductionThe aim of the study was to determine the current state of laboratory’s extra-analytical phase performance by calculating preanalytical and postanalytical phase quality indicators (QIs) and sigma values and to compare obtained data according to desired quality specifications and sigma values reported by The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) Working Group – Laboratory errors and Patient Safety.Materials and methodsPreanalytical and postanalytical phase data were obtained through laboratory information system. Rejected samples in preanalytical phase were grouped according to reasons for rejection and frequencies were calculated both monthly and for 2019. Sigma values were calculated according to “short term sigma” table.ResultsThe number of rejected samples in laboratory was 643 out of 191,831 in 2019. Total preanalytical phase rejection frequency was 0.22%. According to the reasons for rejection, QIs and sigma values were: “Samples with excessive transportation time”: 0.0036 and 5.47; “Samples collected in wrong container” 0.02 and 5.11. In December, QIs and sigma values were: “Samples with excessive transportation time”: 0.01 and 5.34; “Samples collected in wrong container”: 0.03 and 4.98. The postanalytical QIs and sigma values were: “Reports delivered outside the specified time”: 0.34 and 4.21; “Turn around time of potassium”: 56 minute and 3.84, respectively. There were no errors in “Critical values of inpatients and outpatients notified after a consensually agreed time”.ConclusionsExtra-analytical phase was evaluated by comparing it with the latest quality specifications and sigma values which will contribute to improving the quality of laboratory medicine.     

Neurochemical and Neurobehavioral Effects of Low Lead Exposure on the Developing Brain

Lead is found in small but appreciable quantities in air, soil drinking water and food. Exposure to such amounts of lead does not cause acute lead toxicity, but produces subtle effects, particularly in children. The CDC advocates “safe” or “acceptable” levels of blood lead up to 10 μg/dl, while OSHA declares blood lead levels up to 40 μg/dl as “safe” or “acceptable” in the occupationally exposed. The objective of the study was to see if blood levels considered “safe” can cause changes in the biogenic neurotransmitters in the developing brain which may cause neurobehavioral defects like hyperactivity and other cognitive disorders. Albino Wistar rats were divided into the control and lead-treated groups. The control group was given unleaded water, while the lead-treated group was fed with 50 ppm lead acetate in drinking water. On day 45 the animals were subjected to a passive avoidance test, their blood analysed for ZPP and lead. They were then sacrificed and the neurotransmitters—Norepinephrine (NE) and its metabolite—methoxyhydroxyphenylglycol (MHPG) estimated in the brain areas associated with learning and memory—the frontal cortex, hippocampus and the striatum by HPLC-ECD. Our results showed significant increases in blood lead, NE and MHPG, while ZPP increase was insignificant. The rats showed neurobehavioral abnormalities as assessed by the passive avoidance test. We concluded that low blood levels of lead cannot be considered “safe” or “acceptable” as it causes neurotransmitter alterations. Increased NE turnover is implicated in hyperactivity disorders such as ADHD and Tourette syndrome.     

基于“点-面”特征的农村居民点空间形态识别

城乡转型发展进程中的农村居民点用地调整应加强对其空间形态的系统认识与分类研究。本文从“点”-“面”耦合的角度构建农村居民点空间形态概念模型,基于“2+3”式抽样法选取山东省不同区域的5个典型乡镇及其内部的15个典型村庄作为研究对象,分别应用“点”属性的规模、形状和密度指标划分农村居民点类型,利用“面”属性的生产、生活和生态指标剖析农村居民点功能,进而通过对比分析揭示农村居民点“点-面”形态耦合特征。研究发现：①在“点状”形态上,典型乡镇的农村居民点规模差异较大,密度相对集聚,形状偏于不规则;经济落后地区和山区的农村居民点组合类型比较单一,经济发达和平原地区的农村居民点组合类型多样。②在“面状”形态上,农村居民点整体表现为“生产功能较好,生活功能差,生态功能一般”的特征;随着镇域内区位优势的衰减,典型村庄的生产功能逐渐降低并趋于均衡化,生活功能逐渐降低但分化程度更加剧烈,生态功能也逐渐降低但缩减幅度相对均衡。③在“点-面”形态耦合上,大规模-集聚型农村居民点的生活和生态功能偏强,小规模-分散型农村居民点的生活功能稍强,大规模-分散-不规则型农村居民点各项功能均较弱,这种组合类型和功能关系之间的关联性是外部性要素导向下农村居民点内部要素自组织演化的体现。     

A microfluidic device enabling high-efficiency single cell trapping

Single cell trapping increasingly serves as a key manipulation technique in single cell analysis for many cutting-edge cell studies. Due to their inherent advantages, microfluidic devices have been widely used to enable single cell immobilization. To further improve the single cell trapping efficiency, this paper reports on a passive hydrodynamic microfluidic device based on the “least flow resistance path” principle with geometry optimized in line with corresponding cell types. Different from serpentine structure, the core trapping structure of the micro-device consists of a series of concatenated T and inverse T junction pairs which function as bypassing channels and trapping constrictions. This new device enhances the single cell trapping efficiency from three aspects: (1) there is no need to deploy very long or complicated channels to adjust flow resistance, thus saving space for each trapping unit; (2) the trapping works in a “deterministic” manner, thus saving a great deal of cell samples; and (3) the compact configuration allows shorter flowing path of cells in multiple channels, thus increasing the speed and throughput of cell trapping. The mathematical model of the design was proposed and optimization of associated key geometric parameters was conducted based on computational fluid dynamics (CFD) simulation. As a proof demonstration, two types of PDMS microfluidic devices were fabricated to trap HeLa and HEK-293T cells with relatively significant differences in cell sizes. Experimental results showed 100% cell trapping and 90% single cell trapping over 4 × 100 trap sites for these two cell types, respectively. The space saving is estimated to be 2-fold and the cell trapping speed enhancement to be 3-fold compared to previously reported devices. This device can be used for trapping various types of cells and expanded to trap cells in the order of tens of thousands on 1-cm² scale area, as a promising tool to pattern large-scale single cells on specific substrates and facilitate on-chip cellular assay at the single cell level.