Phage display-based generation of novel internalizing antibody fragments for immunotoxin-based treatment of acute myeloid leukemia

The current standard treatment for acute myeloid leukemia (AML) is chemotherapy based on cytarabine and daunorubicine (7 + 3), but it discriminates poorly between malignant and benign cells. Dose-limiting off‑target effects and intrinsic drug resistance result in the inefficient eradication of leukemic blast cells and their survival beyond remission. This minimal residual disease is the major cause of relapse and is responsible for a 5-year survival rate of only 24%. More specific and efficient approaches are therefore required to eradicate malignant cells while leaving healthy cells unaffected. In this study, we generated scFv antibodies that bind specifically to the surface of AML blast cells and AML bone marrow biopsy specimens. We isolated the antibodies by phage display, using subtractive whole-cell panning with AML M2‑derived Kasumi‑1 cells. By selecting for internalizing scFv antibody fragments, we focused on potentially novel agents for intracellular drug delivery and tumor modulation. Two independent methods showed that 4 binders were internalized by Kasumi-1 cells. Furthermore, we observed the AML‑selective inhibition of cell proliferation and the induction of apoptosis by a recombinant immunotoxin comprising one scFv fused to a truncated form of Pseudomonas exotoxin A (ETA''). This method may therefore be useful for the selection of novel disease-specific internalizing antibody fragments, providing a novel immunotherapeutic strategy for the treatment of AML patients.     

Serum levels of antioxidant vitamins, copper, zinc and magnesium in children with chronic rhinosinusitis

Reactive oxygen species including hydroxyl radicals, superoxide anions and hydrogen peroxide which are produced by activated granulocytes play an essential role in many biochemical processes and diseases. Oxidant-mediated tissue damage may be important in the development of chronic sinusitis. The aim of this study was to investigate the serum levels of antioxidant vitamins and elements in 24 children (14 boys and 10 girls, age range: 7-12 years, mean age: 9.2 years) with chronic rhinosinusitis, compared to 20 age and sex matched healthy children. Blood samples were collected in the morning before breakfast and prior to any medication. Vitamin A, E and C levels were determined using reagent kits for high performance liquid chromatography. Cu, Zn and Mg levels were analyzed by atomic absorption spectrometry. Vitamin E, vitamin C, Cu and Zn levels were significantly lower in the patients group than in the control group. However, vitamin A and Mg levels did not differ. In conclusion, serum levels of antioxidant vitamins and elements may be important in the pathogenesis and treatment of chronic rhinosinusitis in children.     

A suggested activity to develop integrated skills and a love of nature in children

Abstract

In this study, a process was designed, in which a lemon seed grew into a seedling, using the inquiry-based science learning approach. This aimed to increase the overall development of the scientific process skills of children and their sensitivity to nature. The germination, growth and development of a plant were meticulously and systematically observed in a long period from seed to seedling. This process contributed to the children’s integration of scientific process skills based on observation and measurement and structuring of concepts related to germination, growth and development in science lessons. It also supported the development of children’s love of nature through allowing them to make meaningful connections with nature.     

A Novel Biosensing System Using Biological Receptor for Analysis of Vascular Endothelial Growth Factor

An immunosensor with rapid and ultrasensitive response for vascular endothelial growth factor (VEGF) has been built up with 4-aminothiophenol (4-ATP) onto the gold surfaces. Quantitative analysis of VEGF was performed by recording the impedance changing of the gold electrode surface by binding of VEGF. The human vascular endothelial growth factor receptor 1 (VEGF-R1, Flt-1) was used as a biorecognition element for the first time in the literature. VEGF-R1 was covalently immobilized via 4-ATP self-assembled monolayer formed on gold thin film covered surface. Construction of the biosensor was carefully characterised by the techniques such as electrochemistry and electrochemical impedance spectroscopy. In order to characterize impedance data, Kramers–Kronig transform was performed on the experimental impedance data. The limit of detection of the immunosensor for qualitative detection was 100 pg/mL while the LOD for quantitative detection could down to 100 pg/mL by using the VEGF-R1 based biosensor. Finally, artificial serum samples spiked with VEGF was analyzed by the proposed immunosensor to investigate useful of the biosensor for early biomarker diagnosis.     

SENSITIVE NITRATE DETERMINATION IN WATER AND MEAT SAMPLES BY AMPEROMETRIC BIOSENSOR

This study describes a novel biosensor method for specific determination of nitrate in food and water samples by using nitrate reductase (NR) (EC 1.9.6.1) biosensor based on the detection of oxidation peak current of redox mediator, methyl viologen, related to nitrate concentration. The method was shown to be selective and sensitive to determine the nitrate levels of water samples and processed meat samples. Immobilization procedure and also working conditions of the biosensor were optimized. Dynamic range attained with this method was established as (5.0–90.0 × 10^?9 M) for nitrate concentration with a 10 s response time. Limit of detection (LOD) and quantification (LOQ) of the biosensor were calculated as 2.2 × 10^?9 M and 5.79 × 10^?9 M, respectively. Reproducibility experiments was established on repetitive measurements by using a freshly prepared biosensor for avoiding the memory effect. The RSD was calculated as 1.22% at a nitrate concentration of 4.7 × 10^?8 M (n = 7).     

A system biology approach to identify regulatory pathways underlying the neuroendocrine control of female puberty in rats and nonhuman primates

This article is part of a Special Issue “Puberty and Adolescence”.     

Prosthetic valvular endocarditis due to the fungus Paecilomyces

The third reported case of prosthetic valvular endocarditis caused by the fungus Paecilomyces is presented. The clinical course of the patient is discussed. The distinctive morphology of the fungus is described, together with the histologic and cytologic features found in the excised prosthetic valve and in the tissues at autopsy. Prosthetic valvular endocarditis presents a serious antibiotic and surgical problem in therapy. Despite antifungal antibiotics and valve replacement this patient died as a result of metastatic cerebral microabscesses and subarachnoid hemorrhage.     

Aging impairs nitric oxide-mediated relaxant responses of rabbit corporal smooth muscle.

Aging has been reported to cause impotence, the mechanism of which is unknown. Therefore, we investigated the effect of aging on electrical stimulation-induced neurogenic, carbachol-induced, endothelium-dependent, and sodium nitroprusside-induced cGMP-dependent relaxant responses of rabbit corporal smooth muscle. Male New Zealand white rabbits were divided into young (4 months), intermediate (8 months), and old (24 months) groups. Electrical stimulation-, carbachol-, sodium nitroprusside-, and papaverine-induced relaxant response in isolated corporal smooth muscle strips were determined using in vitro muscle technique. Although there was no significant difference in the relaxant response of corporal strips to papaverine among the groups, relaxant responses to carbachol and sodium nitroprusside were significantly lower in corporal strips of old group than both young and intermediate groups. However, in the old and intermediate groups, electrical field stimulation-induced neurogenic relaxation was significantly reduced compared with the young group. KCl-induced (124 mM) contractile responses were the same in all groups. Our data indicate that the presence of age-dependent differences in the NO/cGMP-mediated relaxant responses of corporal tissue in the male rabbits. This may contribute to the development of impotence.     

Properties of synaptic noise in tonically active human motoneurons

The objective of these experiments was to determine the amount of synaptic noise on the cell membrane at various intervals after an action potential in a motoneuron firing at a specified frequency. Sources of noise such as variations in the level of voluntary drive were minimized by selecting only segments of the spike train in which the unit was running within prescribed frequency limits. The level of the membrane potential of the motoneuron during these intervals was determined using two test “pulses” (compound Ia excitatory postsynaptic potentials) of known amplitude. This enabled the probability of the membrane potential falling within a voltage “window” of known size at known times after the preceding spike to be determined. The probability density histograms showed that the fluctuations of membrane potential about a target interspike trajectory (i.e., the membrane noise) increased with time after the preceding spike. These fluctuations in the membrane potential can be accounted for by a one-dimensional “random walk” model of membrane noise. This model explains the salient features of the interval histograms, such as positive skewness at low target frequencies. A quantitative test of the model demonstrated its applicability to the motor pools of tibialis and masseter.