A New Sensitive Method for the Detection of Mycoplasmas Using Fluorescence Microscopy.

Contamination of cell cultures by mycoplasmas is a very common phenomenon. As they can substantially alter cell metabolism and potentially spread to all cell cultures in laboratory, their early detection is necessary. One of the fastest and cheapest methods of mycoplasma detection relies on the direct staining of mycoplasmas' DNA by DAPI or Hoechst dyes. Although this method is easy and fast to perform, it suffers from the low signal provided by these dyes compared to the nuclear DNA. Therefore, the reporter cell lines are used for cultivation of mycoplasmas before DAPI or the Hoechst staining step. In the study presented, we have developed and tested a new immunofluorescence assay for the detection of mycoplasmas. The method is based on the enzymatic labeling using DNA polymerase I and modified nucleotides utilizing nicks in the mycoplasmas' DNA. Modified nucleotides are incorporated into mycoplasmas' DNA and subsequently visualized by immunofluorescence microscopy. The developed approach is independent of the mycoplasma strain, does not intensely stain nuclear DNA, does not stain other bacteria, and provides higher sensitivity than the approach based on the direct labeling using DAPI or Hoechst dyes.

Platelet-Derived Mitochondria Display Embryonic Stem Cell Markers and Improve Pancreatic Islet ß-cell Function in Humans.

Diabetes is a major global health issue and the number of individuals with type 1 diabetes (T1D) and type 2 diabetes (T2D) increases annually across multiple populations. Research to develop a cure must overcome multiple immune dysfunctions and the shortage of pancreatic islet ß cells, but these challenges have proven intractable despite intensive research effort more than the past decades. Stem Cell Educator (SCE) therapy-which uses only autologous blood immune cells that are externally exposed to cord blood stem cells adhering to the SCE device, has previously been proven safe and effective in Chinese and Spanish subjects for the improvement of T1D, T2D, and other autoimmune diseases. Here, 4-year follow-up studies demonstrated the long-term safety and clinical efficacy of SCE therapy for the treatment of T1D and T2D. Mechanistic studies found that the nature of platelets was modulated in diabetic subjects after receiving SCE therapy. Platelets and their released mitochondria display immune tolerance-associated markers that can modulate the proliferation and function of immune cells. Notably, platelets also expressed embryonic stem cell- and pancreatic islet ß-cell-associated markers that are encoded by mitochondrial DNA. Using freshly-isolated human pancreatic islets, ex vivo studies established that platelet-releasing mitochondria can migrate to pancreatic islets and be taken up by islet ß cells, leading to the proliferation and enhancement of islet ß-cell functions. These findings reveal new mechanisms underlying SCE therapy and open up new avenues to improve the treatment of diabetes in clinics. Stem Cells Translational Medicine 2017;6:1684-1697.

High lapatinib plasma levels in breast cancer patients: risk or benefit?

AIMS AND BACKGROUND: Lapatinib is a tyrosine kinase inhibitor targeting epidermal growth factor receptors 1 (EGFR/HER1) and 2 (HER2) used in the treatment of patients with HER2-positive breast cancer. The aim of the present study was to determine lapatinib plasma levels in breast cancer patients treated with lapatinib plus capecitabine. PATIENTS AND METHODS: We assessed lapatinib plasma levels in blood samples from 21 breast cancer patients treated with lapatinib plus capecitabine using the standard regimen in an expanded access program. Liquid chromatography tandem mass spectrometry was used for measuring lapatinib plasma concentrations. The validated method was applied for measurement of 55 plasma samples. RESULTS: The median lapatinib plasma level was 5.09 µg/mL, with large interindividual differences. Patients of lower weight tended to have higher lapatinib plasma levels (Spearman correlation coefficient R = -0.435, P = 0.055). One patient's lapatinib plasma levels were markedly higher than those of the others, with a median level of 11.25 µg/mL and repeatedly exceeding 7.80 µg/mL. The treatment was terminated after 8 months when hyperbilirubinemia occurred. CONCLUSIONS: The lapatinib plasma levels reported here are twice as high as the clinically effective steady-state geometric mean maximum concentration. We conclude that increased lapatinib body levels occur when patients are in a nonfasting state at the time of drug intake and when lapatinib doses are not adjusted to low body weight or weight loss during treatment. In Europe, dose adjustments are not recommended in the case of hepatic function impairment. Thus, attention should be paid to changes in liver function test results in clinical practice, especially in patients of small stature and weight, given the risk of high plasma concentrations. Prospective lapatinib plasma level assessment in treated patients might be useful to confirm or refute the possible correlation of high lapatinib plasma levels with hepatic and/or other toxicities.

Analysis of aminoimidazole ribosides by capillary electrophoresis--diagnosing defects in second part of purine biosynthetic pathway.

BACKGROUND: Only three inherited metabolic defects have been identified in purine de novo synthesis (PDNS). We present here CE methods for diagnosing defects in the second half of PDNS (from sixth to tenth enzymatic conversion) based on analysis of aminoimidazole ribosides - dephosphorylated intermediates - in urine. METHODS: Assays were performed in an uncoated fused-silica capillary using two electrophoretic separation systems: 60 mmol/l borate - 2-amino-2-methyl-1-propanol-80 mmol/l sodium dodecylsulfate (pH 9.6) and 200 mmol/l phosphate - sodium (pH 1.8). RESULTS: The reported conditions allowed separation of all metabolites from major urinary constituents with analysis time less than 10 min and separation efficiency of 220 and 350 thousands theoretical plates per meter for borate and phosphate system, respectively. The intra- and interday imprecisions were less than 4.4% and 9.9% CV. Potential usefulness of the methods was demonstrated on samples from a patient with adenylosuccinate lyase deficiency and Chinese hamster ovary cell lines defective in PDNS. CONCLUSIONS: CE is a useful and effective tool in the analysis of aminoimidazole ribosides which enables diagnosis of known as well as not so far identified inherited defects of PDNS pathway.

Montelukast decreases plasma endothelin-1 and serum eosinophil cationic protein levels in paediatric atopic asthma.

BACKGROUND AND OBJECTIVE: Endothelin-1 (ET-1) is produced by vascular endothelial cells and epithelial cells, T-lymphocytes and phagocytes. Increased ET-1 levels have been demonstrated in the bronchial epithelium of asthma patients. In vitro, ET-1 stimulates mucus secretion, activates proinflammatory cells - macrophages and mast cells - and serves as a mitogenic stimulus for fibroblasts and smooth muscle. In addition, ET-1 activates phospholipase 2. Compared with healthy individuals, asthma patients have increased ET-1 levels during an attack and following stabilisation. Our study was designed to examine plasma ET-1 (P-ET) levels in paediatric atopic patients newly diagnosed with persistent mild bronchial asthma and 1 month after initiation of montelukast therapy. METHODS: Patients' histories were examined, and their blood eosinophil leucocyte count and levels of total serum immunoglobulin E (S-IgE), serum eosinophil cationic protein (S-ECP) and P-ET were determined. Thirty-six patients with persistent mild bronchial asthma were treated with the leukotriene receptor antagonist montelukast, administered once a day for 4 weeks. Second P-ET and S-ECP level determinations were made 4 weeks later with all the children included in the study. P-ET levels were also determined in a group of 27 healthy children who had no atopy in their medical histories and were taking no drugs (including montelukast), and who served as controls. RESULTS: The mean +/- SD pretreatment P-ET level in the 36 study children was 11.542 +/- 6.408 pg/L, and this decreased to 5.636 +/- 4.419 pg/L after 1 month's therapy with montelukast (statistically significant difference; p < 0.0001). Both of these values were significantly higher (p < 0.0001 and p < 0.031, respectively) than the mean level in the control group of 27 children (3.543 +/- 2.497 pg/L). The mean pretreatment S-ECP level was 35.78 +/- 19.58 microg/L, and this decreased to 19.54 +/- 13.86 microg/L after 1 month's therapy (p < 0.001). CONCLUSIONS: This study demonstrated a decrease in P-ET levels in children with mild asthma receiving montelukast. This indicates a reduction in the severity of the inflammatory response and, hence, provides evidence for the anti-inflammatory effect of montelukast. Monitoring both ET-1 and ECP levels at regular follow-up may be useful in assessing these two facets of activity of chronic inflammation in bronchial asthma.

The analysis of correlations between drug resistance and clinical/laboratory measures found in a group of children with all treated by ALL-BFM 90 protocol.

This study was designed to assess the predictive value of an MTT (3-[4,5-dimethylthiazol-2,5-diphenyl] tetrazolium bromide) in vitro assay for the evaluation of leukemic cell resistance/sensitivity to cytotoxic drugs, and to compare these results with clinical and laboratory parameters in cases of childhood acute lymphoblastic leukemia (ALL).The chemoresistance of leukemic cells was ascertained by means of an MTT assay in 32 previously untreated children with ALL. The children were treated using the protocol ALL-BFM 90. Statistical correlations were made between in vitro drug resistance to anti-cancer drugs: prednisolone (PRED), vincristine (VCR),daunorubicin (DNR), etoposide (VP-16) and cytosine arabinoside (ARA-C) and in vivo clinical and laboratory parameters: age, sex, risk factor (RF), leukocytes (WBC)and absolute number of blast cells (BC) at diagnosis (BC0), BC at day 8 (BC8), the percentage of blast cells in bone marrow at day 15 (BM15) and at day 33 (BM33),and leukocyte surface antigens CD3, CD4, CD5, CD8, CD10, CD19, CD20, HLADR.