Unraveling the drug distribution in brain enabled by MALDI MS imaging with laser-assisted chemical transfer

Accurate localization of central nervous system(CNS)drug distribution in the brain is quite challenging to matrix-assisted laser desorption/ionization(MALDI)mass spectrometry imaging(MSI),owing to the ionization competition/suppression of highly abundant endogenous biomolecules and MALDI matrix.Herein,we developed a highly efficient sample preparation technique,laser-assisted chemical transfer(LACT),to enhance the detection sensitivity of CNS drugs in brain tissues.A focused diode laser source transilluminated the tissue slide coated with α-cyano-4-hydroxycinnamic acid,an optimal matrix to highly absorb the laser radiation at 405 nm,and a very thin-layer chemical film mainly containing drug molecule was transferred to the acceptor glass slide.Subsequently,MALDI MSI was performed on the chemical film without additional sample treatment.One major advantage of LACT is to minimize ionization competition/suppression from the tissue itself by removing abundant endogenous lipid and protein components.The superior performance of LACT led to the successful visualization of regional distribution patterns of 16 CNS drugs in the mouse brain.Furthermore,the dynamic spatial changes of risperidone and its metabolite were visualized over a 24-h period.Also,the brain-to-plasma(B/P)ratio could be obtained according to MALDI MSI results,providing an alternative means to assess brain penetration in drug discovery.

Down-regulation of Hsp90 could change cell cycle distribution and increase drug sensitivity of tumor cells

AIM:To construct Hsp90 antisense RNA eukaryotic expression vector, transfect it into SGC7901 and SGC7901/VCR of MDR-type human gastric cancer cell lines, HCC7402 of human hepatic cancer and Ec109 of human esophageal cancer cell lines, and to study the cell cycle distribution of the gene transected cells and their response to chemotherapeutic drugs.METHODS:A 1.03kb cDNA sequence of Hsp90beta was obtained from the primary plasmid phHSP90 by EcoR I and BamH I nuclease digestion and was cloned to the EcoR I and BamH I site of the pcDNA by T4DNA ligase and an antisense orientation of Hsp90beta expression vector was constructed. The constructs were transfected with lipofectamine and positive clones were selected with G418. The expression of RNA was determined with dot blotting and RNase protection assay, and the expression of Hsp90 protein determined with western blot. Cell cycle distribution of the transfectants was analyzed with flow cytometry, and the drug sensitivity of the transfectants to Adriamycin (ADR), vincrinstine (VCR), mitomycin (MMC) and cyclophosphamide (CTX) with MTT and intracellular drug concentration of the transfectants was determined with flow cytometry.RESULTS:In EcoR I and BamH I restriction analysis, the size and the direction of the cloned sequence of Hsp90beta remained what had been designed and the gene constructs were named pcDNA-Hsp90.AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones all expressed Hsp90 anti-sense RNA. The expression of Hsp90 was down-regulated in AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones. Cell cycle distribution was changed differently. In AH-SGC7901/VCR and AH-Ec109 cells, G(1) phase cells were increased; S phase and G(2) phase cells were decreased as compared with their parental cell lines. In AH-SGC7901 cell, G(1)phase cells were decreased, G(2) phase cells increased and S phase cells were not changed, and in AH-HCC7402 cells G(1), S and G(2) phase cells remained unchanged as compared with their parental cell lines. The sensitivity of AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 to chemotherapeutic drugs, the sensitivity of AH-SGC7901/VCR to ADR, VCR, MMC and CTX the sensitivity of AH-HCC7402 to ADR and VCR, and the sensitivity of Ec109 to ADR, VCR and CTX all increased as compared with their parental cell lines. The mean fluorescence intensity of ADR in AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 was also significantly elevated (P 【 0.05).CONCLUSION: Down-regulation of Hsp90 could change cell cycle distribution and increase the drug sensitivity of tumor cells.

Distribution and drug resistance of pathogenic bacteria isolated from cancer hospital in 2013

Objective： To understand distribution and drug resistance of pathogenic bacteria from a specialized cancer hospital in 2013 in order to provide a basis for rational clinical antimicrobial agents. Methods： Pathogenic bacteria identification and drug sensitivity tests were performed with a VITEK 2 compact automatic identification system and data were analyzed using WHONET5.6 software.Results： Of the 1,378 strains tested, 980 were Gram-negative bacilli, accounting for 71.1%, in which Klebsiella pneumonia, Escherichia coli and Pseudomonas aeruginosa were the dominant strains. We found 328 Gram-positive coccus, accounting for 23.8%, in which the amount of Staphylococcus aureus was the highest. We identified 46 fungi, accounting for 4.1%. According to the departmental distribution within the hospital, the surgical departments isolated the major strains, accounting for 49.7%. According to disease types, lung cancer, intestinal cancer and esophagus cancer were the top three, accounting for 20.9%, 17.3% and 14.2%, respectively. No strains were resistant to imipenem, ertapenem or vancomycin.Conclusions： Pathogenic bacteria isolated from the specialized cancer hospital have different resistance rates compared to commonly used antimicrobial agents; therefore antimicrobial agents to reduce the morbidity and mortality of infections should be used.

Septoplasty and Decongestant Improve Distribution of Nasal Spray

This study prospectively examined the intranasal distribution of nasal spray after nasal septal correction and decongestant administration. A cohort of 20 patients was assessed for the distribution of nasal spray before and after nasal septum surgery. Sprays were dyed and administered one puff per nostril when patients hold their head up in an upright position. Before and after decongestant admini-stration, the intranasal distribution was semi-quantitatively determined by nasal endoscopy. The results showed that the dyed drug was preferentially sprayed onto the nasal vestibule, the head of the inferior turbinate, the anterior part of septum and nasal floor. As far as the anterior-inferior segment of the nasal cavity was concerned, the distribution was found to be influenced neither by the decongestant nor by the surgery （P〉0.05）. However, both the decongestant and surgery expanded the distribution to the anatomical structures in the superior and posterior nasal cavity such as olfactory fissure, middle turbinate head and middle nasal meatus. No distribution was observed in the sphenoethmoidal recess, posterior septum, tail of inferior turbinate and nasopharynx. It was concluded that nasal septum surgery and decongestant administration significantly improves nasal spray distribution in the nasal cavity.

Visualization of nasal powder distribution using biomimetic human nasal cavity model

Nasal drug delivery efficiency is highly dependent on the position in which the drug is deposited in the nasal cavity.However,no reliable method is currently available to assess its impact on delivery performance.In this study,a biomimetic nasal model based on three-dimensional(3D)reconstruction and three-dimensional printing(3DP)technology was developed for visualizing the deposition of drug powders in the nasal cavity.The results showed significant differences in cavity area and volume and powder distribution in the anterior part of the biomimetic nasal model of Chinese males and females.The nasal cavity model was modified with dimethicone and validated to be suitable for the deposition test.The experimental device produced the most satisfactory results with five spray times.Furthermore,particle sizes and spray angles were found to significantly affect the experimental device’s performance and alter drug distribution,respectively.Additionally,mometasone furoate(MF)nasal spray(NS)distribution patterns were investigated in a goat nasal cavity model and three male goat noses,confirming the in vitro and in vivo correlation.In conclusion,the developed human nasal structure biomimetic device has the potential to be a valuable tool for assessing nasal drug delivery system deposition and distribution.