Novel LC-MS/MS analysis of the GLP-1 analog semaglutide with its application to pharmacokinetics and brain distribution studies in rats.

Semaglutide, one of the most potent glucagon-like peptide (GLP)-1 analogs, has widely been used to treat type II diabetes mellitus and obesity. Recent studies have shown that semaglutide also works on the brain, suggesting its potential utility for various diseases, including Parkinson's disease and Alzheimer's disease. This study aimed to develop a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of semaglutide in both plasma and brain to characterize the pharmacokinetics and brain distribution in rats. Semaglutide was extracted by simple protein precipitation with methanol from plasma and by solid phase extraction from brain tissue. Liraglutide was used as an internal standard. Gradient elution profiles with mobile phases comprising 0.1 % formic acid in water and acetonitrile were used for chromatographic separation. The lower limit of quantification (LLOQ) of the LC-MS/MS assay was 0.5 ng/mL for both rat plasma and brain. Intra- and inter-day accuracy ranged 89.20-109.50 % in the plasma and 92.00-105.00 % in the brain. Precision was within 8.92 % in the plasma and 7.94 % in the brain. Sprague-Dawley rats were given semaglutide by intravenous (IV, 0.02 mg/kg) and subcutaneous (SC, 0.1 and 0.2 mg/kg) injection. Plasma concentrations of semaglutide showed a multi-exponential decline with an average half-life of 7.22-9.26 hr in rats. The subcutaneous bioavailability of semaglutide was 76.65-82.85 %. The brain tissue to plasma partition coefficient (Kp) value of semaglutide was estimated as <0.01. Among the different regions of the brain, semaglutide concentrations were significantly higher in the hypothalamus. The analytical method and pharmacokinetic information may be helpful toward a better understanding of the effect of semaglutide in the brain and further development of GLP-1 analogs for various brain diseases.

Clinical Accuracy of Non-Contact Forehead Infrared Thermometer Measurement in Children: An Observational Study.

We evaluated the clinical reliability and utility of temperature measurements using no-contact forehead infrared thermometers (NCFITs) by comparing their temperature measurements with those obtained using infrared tympanic thermometers (IRTTs) in children. In this observational, prospective, and cross-sectional study, we enrolled 255 children (aged 1 month to 18 years) from the pediatric surgery ward at a tertiary medical center in Korea. The mean age of the children was 9.05 ± 5.39 years, and 54.9% were boys. The incidence rate of fever, defined as an IRTT reading of ≥38.0 °C, was 15.7%. The ICC coefficient for the assessment of agreement between temperatures recorded by the NCFIT and IRTT was 0.87, and the κ-coefficient was 0.83. The bias and 95% limits of agreement were 0.15 °C (−0.43 to 0.73). For an accurate diagnosis of fever (≥38 °C), the false-negative rate was much lower, but the false-positive rate was higher, especially in 6-year-old children. Therefore, NCFITs can be used to screen children for fever. However, a secondary check is required using another thermometer when the child's temperature is >38 °C. NCFITs are proposed for screening but not for measuring the temperature. For the latter, an accurate and reliable thermometer shall be used.

Analysis and Differential Expression of Primo Genes Using RNA-Seq and qRT-PCR Experiments.

Although the existence of the primo vasculature system has been shown in many species, including mice, rats, rabbits and humans, the biological role of this system, including expression of genes and proteins, has not yet been investigated. Especially the transcriptional action by mRNA, which is required for biological action, needs to be studied in primo vasculature biology. Differentially expressed genes in both isolated primo vessels and lymphatic vessels of rabbits were analyzed by RNA sequencing experiments. Primer efficiency and RNA purity of the primo vessels under lipopolysaccharides were confirmed prior to performing real-time qRT-PCR analysis following RNA extraction. We demonstrated that FLT4 was enriched in primo vessels and that several genes, including HSPH1 and EPHB2, were highly expressed in primo vessels compared with lymphatic vessels. Our data show that almost all genes, except HSPA4, were increased or sustained in isolated primo vessels compared with lymphatic vessels (FLT4 2.58 fold, HSPH1 1.83 fold, EPHB2 1.52 fold; whereas HSPA4 decreased 0.50 fold), suggesting primo vessels as a central regulator in diverse physiology. This implies that FLT4, HSPH1, and EPHB2 in high amounts may be involved in the functional activity of primo vessels. Our experimental data show that several genes are highly enriched in primo vessels in the lymphatic vessels of the rabbit.

Author Correction: Synthesis of MgAC-Fe3O4/TiO2 hybrid nanocomposites via sol-gel chemistry for water treatment by photo-Fenton and photocatalytic reactions.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Synthesis of MgAC-Fe3O4/TiO2 hybrid nanocomposites via sol-gel chemistry for water treatment by photo-Fenton and photocatalytic reactions.

MgAC-Fe3O4/TiO2 hybrid nanocomposites were synthesized in different ratios of MgAC-Fe3O4 and TiO2 precursor. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray fluorescence spectrometry (XRF), electron spin resonance spectrometry (ESR), Brunauer-Emmett-Teller (BET), photoluminescence (PL), and UV photoelectron spectroscopy (UPS) were used to characterize the nanocomposites. The increase of MgAC-Fe3O4, in the hybrid nanocomposites' core-shell structure, led to the decrease of anatase TiO2 peaks, thus reducing the photo-Fenton and photocatalytic activities. According to the obtained data, MgAC-Fe3O4 [0.05 g]/TiO2 showed the best photo-Fenton and photocatalytic activities, having removed ~93% of MB (photo-Fenton reaction) and ~80% of phenol (photocatalytic reaction) after 20 and 80 mins, respectively. On the pilot scale (30 L), MgAC-Fe3O4 [0.05 g]/TiO2 was completely removed after 27 and 30 hours by the photo-Fenton and photocatalytic activities, respectively. The synergistic effect gained from the combined photo-Fenton and photocatalytic activities of Fe3O4 and TiO2, respectively, was credited for the performances of the MgAC-Fe3O4/TiO2 hybrid nanocomposites.

Differential Gene Expression by RNA-Seq Analysis of the Primo Vessel in the Rabbit Lymph.

For the connectome of primo vascular system, some long-type primo vessels dyed with Alcian blue injected into inguinal nodes, abdominal node, and axially nodes were visualized, which passed over around the vena cava of the rabbit. The Alcian blue dye revealed primo vessels and colored blue in the rabbit lymph vessels. The length of long-type primo vessels was 18 cm on average, of which diameters were about 20-30 µm, and the lymph vessels had diameters of 100-150 µm. Three different tissues of pure primo vessel, mixed primo + lymph vessel, and only lymph vessel were made to undergo RNA-Seq analysis by next-generation sequencing. We also analyzed differentially expressed genes (DEGs) from the RNA-Seq data, in which 30 genes of the primo vessels, primo + lymph vessels, and lymph vessels were selected for primo marker candidates. From the plot of DEG analysis, 10 genes had remarkably different expression pattern on the Group 1 (primo vessel) vs Group 3 (lymph vessel). With Fragments Per Kilobase of exon per Million the cutoff p-value for each gene was < 0.05. Fragments Per Kilobase of exon per Million of the 10 genes such as IGHM, HLA-DRA, HIST1H41, LPL, CD36, SRGN, DGAT2, SNCG, CD48, and GPD1 for primo vessels compared with those of lymph vessels increased twice or thrice. These results suggest that the selected genes could be used for the specific marker to construct primo connectome of circuit system in the rabbit.