Richard Prusa

A checklist for critical appraisal of studies of biological variation

Abstract Data on biological variation are used for many purposes in laboratory medicine but concern exists over the validity of the data reported in some studies. A critical appraisal checklist has been produced by a working group established by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) to enable standardised assessment of existing and future publications of biological variation data. The checklist identifies key elements to be reported in studies to enable safe accurate and effective transport of biological variation data sets across healthcare systems. The checklist is mapped to the domains of a minimum data set required to enable this process.

Utilizing of Adsorptive Transfer Stripping Technique Brdicka Reaction for Determination of Metallothioneins Level in Melanoma Cells, Blood Serum and Tissues.

In the paper we utilized the adsorptive transfer stripping differential pulse voltammetry Brdicka reaction for the determination of metallothioneins (MT) in melanoma cells, animal melanoma tissues (MeLiM miniature pig) and blood serum of patients with malignant melanoma. Primarily we attempted to investigate the influence of dilution of real sample on MT electrochemical response. Dilution of samples of 1 000 times was chosen the most suitable for determination of MT level in biological samples. Then we quantified the MT level in the melanoma cells, the animal melanoma tissues and the blood serum samples. The MT content in the cells varied within the range from 4.2 to 11.2 μM. At animal melanoma tissues (melanomas localized on abdomen, back limb and dorsum) the highest content of MT was determined in the tumour sampled on the back of the animal and was nearly 500 μg of MTs per gram of a tissue. We also quantified content of MT in metastases, which was found in liver, spleen and lymph nodes. Moreover the average MT level in the blood serum samples from patients with melanoma was 3.0 ± 0.8 μM. MT levels determined at melanoma samples were significantly (p < 0.05) higher compared to control ones at cells, tissues and blood serum.

Changes of orexin A plasma levels in girls with anorexia nervosa during eight weeks of realimentation.

OBJECTIVE Orexin A (OXA) is a hypothalamic neuropeptide involved in regulation of food intake and nutritional status. There are multiple disturbances of neuropeptide signaling described in girls with anorexia nervosa (AN), but OXA levels have not been addressed in this population to date. Therefore, we analyzed OXA levels of AN girls in this study. METHOD OXA (radioimmunoassay/RIA/method), leptin, insulinlike growth factor-1 (IGF-1), and insulinlike growth factor-1 binding protein-3 (IGFBP-3) levels were measured before and after 8 weeks of realimentation in 36 girls with AN and in 14 healthy controls (control group: CG). RESULTS Average weight increased significantly in AN during the study (p < .0001), while plasma levels of OXA decreased (before realimentation: 56.2 ± 2.4 pg/ml; after realimentation: 47.5 ± 1.4 pg/ml; p = .0025). OXA levels before realimentation differed from levels in the CG (47.15 ± 2.6 pg/ml, p = .034), but not afterward. We did not find any correlation between OXA and age, height, weight, BMI; or IGF-1, IGFBP-3, and leptin levels. DISCUSSION OXA levels in untreated AN patients differ significantly from healthy subjects and decrease during realimentation. These findings indicate that OXA may be involved in the nutritional regulation of malnourished children and adolescents.

Serum cystatin C level for better assessment of glomerular filtration rate in cystic fibrosis patients treated by amikacin

Background and objective:  Monitoring of renal function in cystic fibrosis (CF) patients is essential. The dosage regimen of amikacin is regularly modified according to the patient’s glomerular filtration rate (GFR). The aim of the study was to evaluate the use of cystatin C (CyC) for monitoring amikacin therapy along with other markers of renal tubular and glomerular function, and damage [N‐acetyl‐β‐d glucosaminidase (NAG), creatinine level and creatinine clearance].

The importance of therapeutic drug monitoring (TDM) for parenteral busulfan dosing in conditioning regimen for hematopoietic stem cell transplantation (HSCT) in children.

BACKGROUND Series of observations indicate PK/PD variability challenging the accuracy of the body-weight based busulfan (Bu) dosing schedule for (HSCT) conditioning therapy. The purpose of this communication is to describe the frequency of dose changes in initially body-weight-based fixed IV Bu dose and to emphasize the importance of TDM. MATERIAL AND METHODS Sixty-two children (ages 2 months-18 years) were treated with IV busulfan doses based on body weight for myeloablation. TDM utilizing a limited sample strategy (trough concentration immediately before the 5th dose, followed by samples immediately after the end of the 2-h infusion peak, 4 h, and 6 h from initiation of the infusion) was performed in 46 of 62 subjects. Busulfan concentrations were determined by high-performance liquid chromatography (HPLC). AUC was calculated according to the trapezoidal rule. RESULTS We observed trough levels of 25-1244 µg/L, peak levels of 849-4586 µg/L, and AUC of 2225-12818 µg/L·h following body weight-based high-dose busulfan. The doses were changed in 54% of cases. AUC in 5 of 9 patients with VOD were within target, in 3 patients AUS was higher, and in 1 patient AUC was lower. One of the 2 patients with neurotoxicity had higher AUC. Engraftment was 100%, but relapse occurred in 25% of cases. CONCLUSIONS Our results demonstrate that even with IV busulfan, intra-individual PK/PD variability is challenging. Although AUC does not necessarily correspond with outcomes (due to the role of other factors the fact that doses were changed in 54% of cases underlines the importance of TDM.

An Adsorptive Transfer Technique Coupled with Brdicka Reaction to Reveal the Importance of Metallothionein in Chemotherapy with Platinum Based Cytostatics

The drugs based on platinum metals represent one of the oldest, but also one of the most effective groups of chemotherapeutic agents. Thanks to many clinical studies it is known that resistance of tumor cells to drugs is a frequent cause of chemotherapy failure. With regard to platinum based drugs, multidrug resistance can also be connected with increased expression of low-molecular weight protein metallothionein (MT). This study aimed at investigating the interactions of MT with cisplatin or carboplatin, using the adsorptive transfer technique coupled with differential pulse voltammetry Brdicka reaction (AdTS DPV Brdicka reaction), and a comparison of in vitro results with results obtained in vivo. The results obtained from the in vitro study show a strong affinity between platinum based drugs and MT. Further, we analyzed extracts of neuroblastoma cell lines treated with cisplatin or carboplatin. It is clear that neuroblastoma UKF-NB-4 cisplatin-resistant and cisplatin-sensitive cell lines unlikely respond to the presence of the platinum-based cytostatics cisplatin and carboplatin. Finally, we determined the level of MT in samples from rabbits treated with carboplatin and patients with retinoblastoma treated with the same drug.

Urinary uric acid excretion in healthy male infants

Abstract.  Blood and urine samples were collected from 23 healthy term male infants aged 2 – 12 months (mean 6.6 months). Data for establishing urinary uric acid reference values were obtained: urine concentration, 24-h urine output, weight-related urine output, urine output related creatinine, clearance, and fractional excretion. A negative correlation with age was demonstrated for all parameters studied.

Urine and Serum Cathepsin B Concentrations in the Transitional Cell Carcinoma of the Bladder

It has been shown that expression and activity of lysosomal proteolytic enzymes (i.e., cathepsin B) correlate with tumor progression in various neoplasms. We investigate possible correlation of cathepsin B concentrations with grading and invasivity of tumorous bladder tissue.

Re‐evaluation of cord blood arterial and venous reference ranges for pH, pO2, pCO2, according to spontaneous or cesarean delivery

Umbilical cord blood gas analysis (pO2 and pCO2) is now recommended in all high‐risk baby deliveries and in some centers it is performed routinely following all deliveries. The aim of this study was to re‐evaluate cord blood arterial and venous reference ranges for pH, pO2, pCO2 in newborns, delivered by spontaneous vaginal delivery (SVD) and by cesarean section (CS) performed in Faculty Hospital Motol. Two groups of subjects were selected for the study. Group I consisted of 303 newborns with SVD. Group II consisted of 189 newborns delivered by cesarean section. Cord blood samples were analyzed for standard blood gas and pH, using the analytical device Rapid Lab 845 and Rapid Lab 865. We obtained reference values expressed as range (lower and upper reference value expressed as 2.5 and 97.5 percentiles) for cord blood in newborns with SVD: arterial cord blood: pH=7.01–7.39; pCO2=4.12–11.45 kPa; pO2=1.49–5.06 kPa; venous cord blood: pH=7.06–7.44; pCO2=3.33–9.85 kPa; pO2=1.80–6.29 kPa. We also obtained reference values for cord blood in newborns delivered by CS: arterial cord blood: pH=7.05–7.39; pCO2=5.01–10.60 kPa; pO2=1.17–5.94 kPa; venous cord blood: pH=7.10–7.42; pCO2=3.88–9.36 kPa; pO2=1.98–7.23 kPa. Re‐evaluated reference ranges play essential role in monitoring conditions of newborns with spontaneous and caesarean delivery. J. Clin. Lab. Anal. 24:300–304, 2010.

Improving laboratory efficiencies through significant time reduction in the preanalytical phase

Total turnaround time (TAT) in laboratory testing has been traditionally characterized as the time from specimen collection to the reporting of results (1, 2). Despite improvements in analytical testing systems (i.e., automation), little to no measurable improvements have been demonstrated for the preanalytical phase of TAT. Efforts to address some aspects of the preanalytical phase, specifically specimen transport (i.e., pneumatic tubes), as well as efforts to streamline laboratory processes (i.e., Lean), have had little impact on TAT. Total laboratory TAT remains a pertinent issue in today’s healthcare environment (3). In addition, with the growth in the aging population, the volume of medical services, particularly in the clinical laboratory, has increased. Since the information utilized for patient diagnosis and treatment management is often based on laboratory results, this increase may also cause additional pressure to optimize the length of the total testing process in order to assure effective patient care and to reduce unnecessary delays and costs (4–6). In a Q-probes survey from the College of American Pathologists on Emergency Department (ED) TAT, laboratory TAT was felt to cause delayed treatment and increased length of stay in the ED more than half of the time (7). Therefore, total TAT continues to be a factor in assessing laboratory