Dynamic Thiol-Disulfide Homeostasis in Lung Transplant Recipients.

OBJECTIVES: In this study, we investigated dynamic thiol-disulfide homeostasis as a new indicator of oxidative stress in lung transplant recipients. In addition, we compared dynamic thiol-disulfide homeostasis parameters according to transplant indication and time after transplant. MATERIALS AND METHODS: This study had a single-center, observational, randomized design. In terms of transplant indications, lung transplant recipients were grouped as chronic obstructive pulmonary disease, interstitial lung disease, bronchiectasis, and other indications. To make comparisons based on time after transplant, lung transplant recipients were categorized into the following groups: >6 and ≤24 months, >24 and ≤48 months, >48 and ≤72 months, and >72 months. A fully automated spectrophotometric technique was used to measure dynamic thiol-disulfide homeostasis in fasting blood samples. RESULTS: Our study included 34 lung transplant recipients and 36 healthy volunteers. Native thiol (P = .005) and total thiol levels (P = .06) were lower in lung transplant recipients. Disulfide levels were similar. Disulfide-to-native thiol (P = .027) and disulfide-to-total thiol ratios (P = .027) were significantly higher in lung transplant recipients. Native thiol-to-total thiol ratios were lower in lung transplant recipients (P = .027). When we examined patients according to transplant indication, no statistically significant differences were found in dynamic thiol-disulfide homeostasis parameters, except for total thiol and disulfide levels. We also found no significant differences when we examined dynamic thiol-disulfide homeostasis parameters according to time after transplant. CONCLUSIONS: Thiol-related antioxidant activity is significantly reduced after lung transplant, regardless of indication and transplant time. Ensuring oxidative balance in lung transplant recipients with an antioxidant supplement regimen can prevent damage from oxidative stress.

Dynamic Thiol-Disulfide Homeostasis as a Marker for Oxidative Stress in Lung Transplant Candidates.

OBJECTIVES: Oxidative stress developing due to oxidant/antioxidant imbalance plays a crucial role in the etiopathogenesis of chronic progressive lung diseases.The condition is typically more severe in lung transplant candidates with end-stage lung disease. Here, we investigated dynamic thiol-disulfide homeostasis as a marker for oxidative stress in lung transplant candidates. MATERIALS AND METHODS: The study included 40 patients with end-stage lung disease with indications for lung transplant (candidate group) and 40 healthy controls. Patient demographic data, laboratory results, and thiol-disulfide homeostasis values were recorded. We categorized patients according to their primary diseases and noted clinical measurements of forced expiratory volume in 1 second, forced vital capacity, 6-minute walk test, systolic pulmonary artery pressure, and lung allocation scores.Thiol-disulfide homeostasis parameters were compared before and after transplant. RESULTS: Demographic characteristics were similar in the candidate and control groups. In the candidate group, native thiol and total thiol levels (antioxidant parameters of thiol-disulfide homeostasis) were significantly lower, whereas disulfide-to-native thiol and disulfide-to-total thiol ratios (oxidant parameters of thiol-disulfide homeostasis) were significantly higher. We observed no significant differences between the disease subgroups in terms of thioldisulfide homeostasis parameters. Moderately significant correlations were shown between the antioxidant markers ofthiol-disulfide homeostasis and the clinical measurements, including the lung allocation scores. Our multiple regression analyses showed that native thiol and total thiol were significant predictive factors to estimate the lung allocation score. During the study period, 6 patients (15%)received lung transplant. There were significant differences in antioxidant parameters ofthiol-disulfide homeostasis in the pre- versus posttransplant periods. CONCLUSIONS: In patients with end-stage lung disease, the dynamic thiol-disulfide homeostasis status is altered in favor of oxidants. Thus, thiol-disulfide homeostasis parameters can be used to detect oxidative stress and estimate lung allocation scores in these patients. Lung transplant may have positive effects on oxidative stress.

Effects of specimen haemolysis on complete blood count results by Abbott Alinity hq System.

INTRODUCTION: The current study aimed to assess the interference of in vitro haemolysis on complete blood count (CBC) using Abbott Alinity hq system, and to determine which haemolysis levels affect the reliability of sample results. MATERIALS AND METHODS: Blood samples obtained from 25 volunteers in K3-EDTA tubes were divided into four aliquots. The first aliquot was not subjected to any intervention. The second, third and fourth aliquots were passed through a fine needle 2, 4 and 6 times, respectively. Complete blood count was performed by multi-angle polarized scatter separation technology and haemolysis index (HI) was assessed from the plasma samples separated by centrifugation. Five groups were formed according to the HI values. The percentage biases between the results of non-haemolysed and haemolysed groups were compared with the desirable bias limits from The European Federation of Clinical Chemistry and Laboratory Medicine database and reference change values (RCVs). RESULTS: In groups 1 to 4, the effects of haemolysis on CBC parameters were acceptable comparing to the analytical bias except for lymphocytes (7.26%-7.42%), MCH (2.59%), and MCHC (0.47%-2.81%). Results of group 5 (gross haemolysis) showed decreases in HCT(- 4.56%), RBC (- 4.07%) count and increase in lymphocyte (11.60%) count higher than the analytical performance specifications. Moreover, variations in MCH (4.65%) and MCHC (5.24%) were exceeding the RCVs. CONCLUSIONS: Gross haemolysis (haemoglobin concentration > 10 g/L) is likely to produce unreliable CBC results on non-pathological samples. Further studies including pathological specimens are needed.

Evaluation of the efficiency of serum biotinidase activity as a newborn screening test in Turkey.

OBJECTIVES: Biotinidase Deficiency (BD) is an autosomal recessive metabolic disorder. However, the relationship between genotype and biochemical phenotype has not been completely elucidated yet. But still, some mutations are accepted to be associated with profound or partial deficiency. We aimed to evaluate the results of biochemical enzyme activity in accordance with the presence of genetic mutations and investigate the correlation between genotype and biochemical phenotype together in the study. METHODS: This retrospective study was carried out using data from medical records of 133 infants detected by the newborn screening followed by serum biotinidase activity (BA) detection with semi-quantitative colorimetric method. Mutation analysis was performed to confirm the diagnosis. In addition, the expected biochemical phenotype based on the known mutant alleles were compared with the observed biochemical phenotype. RESULTS: When confirmed with mutation analysis results, the diagnostic sensitivity and specificity of serum BA with spectrophotometric method was 93.1% and 95.1%, respectively. In 93.98% of the cases conformity was observed between the biochemical phenotype and the genotype. The c.1330 G>C(p.D444H) and c.470 G>A (p.Arg157His) were the most common allelic variants with frequencies of 63.69% and 33.75%, respectively. CONCLUSIONS: The diagnostic test is supposed to have a high sensitivity to identify asymptomatic BD patients. Apparently healthy cases with almost normal enzyme activity and a variant allele in the genetic analysis were reported to present symptoms under stress conditions, which should be kept in mind. This study can be accepted as an informative report as it may contribute to the literature in terms of the allelic frequency and determination of the relation between genotype and biochemical phenotype. Also, method verification including the assessment of possible effects of non-genetic factors on BA according to the certain mutation types is warranted.

Determining biological variation of serum parathyroid hormone in healthy adults.

INTRODUCTION: Measurement of parathyroid hormone (PTH) is essential in the investigation and management of calcium metabolism disorders. To assess the significance of any assay result when clinical decision making biological variation (BV) of the measurand must be taken into consideration. The aim of the present study is determining the BV parameters for serum PTH. MATERIALS AND METHODS: Blood samples were taken at weekly intervals from 20 healthy subjects for ten weeks in this prospective BV study. Serum "intact PTH" concentrations were measured with electrochemiluminescence method. Biological variation parameters were estimated using the approach proposed by Fraser. RESULTS: The values of within-subject biological variation (CVI), between-subject biological variation (CVG), analytical variation (CVA), reference change value (RCV) and individuality index (II) for serum PTH were 21.1%, 24.9%, 3.8%, 59.4% and 0.8%, respectively. Within-subject biological variation and CVG were also determined according to gender separately; 18.5% and 24.0%; 26.2% and 18.6% for male and female, respectively. Calculated desirable precision and bias goals were < 10.6% and < 6.3%, respectively. CONCLUSION: This study may contribute to BV data on serum PTH as it includes a sufficient number of volunteers from both genders over an acceptable period of time. We do not recommend the usage of population-based reference intervals for serum PTH concentrations. Reference change value may be helpful for the evaluation of serial serum PTH results. Nonetheless, evaluation of data according to gender is necessary when setting analytical performance specifications.

Comparison of the effect of gel used in two different serum separator tubes for thyroid function tests.

BACKGROUND: Selection and verification of blood collection tubes is an important preanalytical issue in clinical laboratories. Today, gel tubes are commonly used with many advantages, although they are known to cause interference in immunoassay methods. In this study, we aimed to compare SSTs of two different suppliers (Ayset clot activator & Gel and Becton Dickinson (BD) Vacutainer SST II advance) with reference tubes and evaluate the effect of storage time in terms of commonly used endocrine tests such as thyroid-stimulating hormone (TSH), free thyroxine (fT4), and free triiodothyronine (fT3). METHODS: Fifty-five volunteers were included in the study. Samples were taken into three different tubes and analyzed for serum TSH, fT4, and fT3 on Architect ci8200 Immunoassay System. Clinical decision levels were estimated using total allowable error (TEa). RESULTS: No difference was found between tubes in terms of TSH, fT3, and fT4 levels. From a statistical standpoint, TSH and fT4 levels were no longer stable during 24, 48, and 72 hours storage time periods. However, their variations were not clinically significant. CONCLUSION: Ayset clot activator & Gel tubes and BD Vacutainer SST II advance tubes have comparable results with glass tube in terms of TSH, fT3, and fT4 levels on Architect ci8200 Immunoassay Systems. From a clinical standpoint, serum TSH, fT4, and fT3 concentrations may be considered as stable when storing these tubes over 72 hours.

Stability of urine specimens stored with and without preservatives at room temperature and on ice prior to urinalysis.

OBJECTIVES: Laboratories determine the most appropriate approach for the collection and transport of urine specimens. We investigated the effect of a chlorhexidine-based preservative tube on sample stability, compared the results of refrigerated polystyrene tubes with no additives, and investigated the effect of temperature on the performance of preservative tubes. DESIGN AND METHODS: Fresh urine specimen (n=48) aliquots in BD Vacutainer® Plus Urinalysis Preservative Tubes and polystyrene tubes were analyzed on an Iris Diagnostics iQ200. Samples in polystyrene tubes were refrigerated for 4 and 8h. Four aliquots in preservative tubes were kept at room temperature for 4, 8, 24, and 72h, while two aliquots were kept on ice for 4 and 8h. RESULTS: There was good agreement for all chemistry and microscopy parameters with the exceptions of white blood cells (WBCs) at 24 and 72h and red blood cells (RBCs) at 72h. Preservative tubes on ice showed a significant decrease in concordance of WBCs and calcium oxalate (CaOx) parameters compared with the results at room temperature. Results of refrigerated polystyrene tubes showed good agreement with the exceptions of WBC clumps and amorphous crystal at 8h. CONCLUSIONS: A chlorhexidine-containing preservative tube seems advantageous for urine sample transport from outside healthcare services. A preservative tube offers comparable results with urine samples kept in a refrigerator for 4-8h for the majority of parameters. Keeping samples at room temperature is recommended when preservative tubes are used because ice produces a negative effect on WBCs and CaOx.