Short-term effects of streptozotocin-induced diabetes on the electrocardiogram, physical activity and body temperature in rats

A variety of contractility defects have been reported in the streptozotocin (STZ)-induced diabetic rat heart including alterations to the amplitude and time course of cardiac muscle contraction. Transmitter devices were surgically implanted in the peritoneal cavity of young adult male Wistar rats. Electrodes from the transmitter were arranged in Einthoven bipolar lead II configuration. Electrocardiogram (ECG), physical activity and body temperature data were continuously recorded with a telemetry system before and following the administration of STZ (60 mg kg-1). Heart rate (HR), physical activity and body temperature declined rapidly 3-5 days after administration of STZ. The effects became more conspicuous with time and reached a new steady state approximately 10 days after STZ treatment when HR was 255+/-8 beats min-1 in diabetic rats compared to 348+/-17 beats min-1 in age-matched controls. Heart rate variability (HRV) was also significantly reduced after STZ treatment (18+/-3 beats min-1) compared to controls (36+/-3 beats min-1). Reduced physical activity and/or body temperature may partly underlie the reduction in HR and HRV. Reductions in power spectral density at higher frequencies (2.5-3.5 Hz) suggest that parasympathetic drive to the heart may be altered during the early stages of STZ-induced diabetes. Short-term diabetes-induced changes in vital signs can be effectively tracked by continuous recording using a telemetry system.     

Molecularly imprinted polymeric coatings for sensitive and selective gravimetric detection of artemether

Monitoring antimalarial drugs is necessary for clinical assays, human health, and routine quality control practices in pharmaceutical industries. Herein, we present the development of sensor coatings based on molecularly imprinted polymers (MIPs) combined with quartz crystal microbalance (QCM) for sensitive and selective gravimetric detection of an antimalarial drug: artemether. The MIP coatings are synthesized by using artemether as the template in a poly(methacrylic acid-co-ethylene glycol dimethacrylate) matrix. Artemether-MIP and the non-imprinted polymer (NIP) control or reference layers are deposited on 10 MHz dual-electrode QCM by spin coating (187 ± 9 nm layer thickness after optimization). The coatings are characterized by FTIR spectroscopy and atomic force microscopy that reveal marked differences among the MIP and NIP. The MIP-QCM sensor exhibits high sensitivity (0.51 Hz ppm⁻¹) with sub-10 ppm detection and quantification limits. The MIP-QCM sensor also exhibits a 6-fold higher sensitivity compared to the NIP-QCM, and a dynamic working range of 30–100 ppm. The response time of MIP-QCM devices for a single cycle of analyte adsorption, signal saturation, and MIP regeneration is less than 2.5 min. The sensor also demonstrates selectivity factors of artemether-MIP of 2.2 and 4.1 compared to artemisinin and lumefantrine, respectively. Reversibility tests reveal less than 5% variation in sensor responses over three cycles of measurements at each tested concentration. The MIP-QCM showed lower detection limits than conventional HPLC-UV, and faster response time compared to HPLC-UV and liquid chromatography-mass spectrometry (LC-MS).

Chemical structures of the antimalarial drugs: artemisinin, artemether (a methyl ether derivative of artemisinin), and lumefantrine.     

Beyond bone biology: Lessons from team science

Today, research in biomedicine often requires the knowledge and technologies in diverse fields. Therefore, there is an increasing need for collaborative team science that crosses traditional disciplines. Here, we discuss our own lessons from both interdisciplinary and transdisciplinary teams, which ultimately ushered us to expand our research realm beyond bone biology.     

Theoretical and Experimental in vitro Antifungal and Antitumor Activities of Organotin(IV) Derivatives of 3-(4-nitrophenyl)-2-methylacrylic acid

Pharmaceutical Chemistry Journal - Di- and triorganotin(IV) derivatives of 3-(4-nitrophenyl)-2-methylacrylic acid (HL), i.e., [n-Bu2SnL2] (1), [Me2SnL2] (2), [n-Bu3SnL]n (3) [Me3SnL]n (4) and...     

Ameliorative effect of vitamin C on the haematological changes induced by exposure of chlorpyriphos and lead acetate in Wistar rats

The present study was designed to evaluate the effects of chlorpyriphos, lead acetate and vitamin C alone and in combinations, on various haematological parameters in Wistar rats. Rats of 150–200 g body weight were divided into eight groups of six animals each and were subjected to various daily oral treatment regimes for 98 days. Group C served as control receiving only corn oil, group CP received chlorpyriphos at 5.5 mg/kg in corn oil and group L received lead acetate at100?ppm in water, whereas animals in group CP + L received a combination of chlorpyriphos at 5.5 mg/kg in corn oil and lead acetate at 100 ppm in water. Group VC received vitamin C at 100 mg/kg in water; group CP + VC received a combination of chlorpyriphos at 5.5 mg/kg and vitamin C at 100 mg/kg; group L + VC received lead acetate at 100 ppm in water and vitamin C at 100 mg/kg and group CP + L + VC received chlorpyriphos at 5.5 mg/kg, lead acetate at 100 ppm in water and vitamin C at 100 mg/kg. Blood samples were collected on days 0, 30, 60 and 98 post exposure and analysed for packed cell volume (PCV), total erythrocyte count (TEC), haemoglobin (Hb), erythrocyte sedimentation rate (ESR), total leucocyte count (TLC) and differential leucocyte count. A significant decrease in TEC, PCV and Hb and a significant increase in ESR values were observed. However, lead acetate caused an increase in TLC while chlorpyriphos resulted in a decrease in TLC. Both of these toxicants potentiated toxicity of each other. The study demonstrated that treatment of chlorpyriphos- and lead-treated rats with vitamin C significantly altered some of the important haematological parameters revealing the protective effect of this vitamin against haematological alterations induced by chlorpyriphos and lead.     

Synthesis of Ni–Ag–ZnO solid solution nanoparticles for photoreduction and antimicrobial applications

ZnO is one of the most promising and efficient semiconductor materials for various light-harvesting applications. Herein, we reported the tuning of optical properties of ZnO nanoparticles (NPs) by co-incorporation of Ni and Ag ions in the ZnO lattice. A sonochemical approach was used to synthesize pure ZnO NPs, Ni–ZnO, Ag–ZnO and Ag/Ni–ZnO with different concentrations of Ni and Ag (0.5%, 2%, 4%, 8%, and 15%) and Ni doped Ag–ZnO solid solutions with 0.25%, 0.5%, and 5% Ni ions. The as-synthesized Ni–Ag–ZnO solid solution NPs were characterized by powdered X-ray diffraction (pXRD), FT-IR spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), UV-vis (UV) spectroscopy, and photoluminescence (PL) spectroscopy. Ni–Ag co-incorporation into a ZnO lattice reduces charge recombination by inducing charge trap states between the valence and conduction bands of ZnO and interfacial transfer of electrons. The Ni doped Ag–ZnO solid solution NPs have shown superior 4-nitrophenol reduction compared to pure ZnO NPs which do not show this reaction. Furthermore, a methylene blue (MB) clock reaction was also performed. Antibacterial activity against E. coli and S. aureus has inhibited the growth pattern of both strains depending on the concentration of catalysts.

The synergic effect of Ni and Ag in Ni–Ag–ZnO solid solutions has tuned the optoelectronic properties of ZnO for photoreduction reactions.