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 RNAeukaryotic expression vector, transfect it intoSGC7901 and SGC7901/VCR of MDR-type humangastric cancer cell lines, HCC7402 of humanhepatic cancer and Eel09 of human esophagealcancer cell lines, and to study the cell cycledistribution of the gene transected cells andtheir response to chemotherapeutic drugs.METHODS A I .03kb cDNA sequence of Hsp90Pwas obtained from the primary plasmid phHsp90by EcoR 1 and BamH I nuclease digestion andwas cloned to the EcoR 1 and BamH 1 site ofthe pcDNA by T4DNA ligase and an antisenseorientation of Hsp900 expression vector wasconstructed. The constructs were transfectedwith lipofectamine and positive clones wereselected with G418. The expression of RNA wasdetermined with dot blotting and RNaseprotection assay, and the expression of Hsp90protein determined with Western blot. Cell cycledistribution of the transfectants was analyzedwith flow cytometry, and the drug sensitivity ofthe transfectants to adriamycin (ADR ),vincrinstine (VCR ), mitomycin (MMC ) andcyclophosphamide (CTX ) with MTT andintracellular drug concentration of thetransfectants was determined with flowcytometry.RESULTS In EcoR 1 and BamH I restrictionanalysis, the size and the direction of the clonedsequence of Hsp900 remained what had beendesigned and the gene constructs were namedpcDNA-Hsp90. AH^SGC7901, AH^SGC7901/ VCR,AH-HCC7402 and AH-Eel09 cell clones allexpressed Hsp90 anti--sense RNA. Theexpression of Hsp90 was down--regulated in AHSGC7901, AH--SGC7901/ VCR, AH-HCC7402 andAH--Eel09 cell clones. Cell cycle distribution waschanged differently. In AH-SGC7901/ VCR andAH-Ec109 cells, G, phase cells were increased; Sphase and G, phase cells were decreased ascompared with their parental cell lines. In AHSGC7901 cell, G, phase cells were decreased, Qphase cells increased and S phase cells were notchanged, and in AH-HCC7402 cells G,, S and qphase cells remained unchanged as comparedwith their parental cell lines. The sensitivity ofAH--SGC7901, AH--SGC7901/ VCR, AH-HCC7402 andAH-Ec109 to chemotherapeutic drugs, thesensitivity ot AH--SGC7901/ VCR to ADR, VCR,MMC and CTX the sensitivity of AH-HCC7402 toADR and VCR, and the sensitivity of Eel09 toADR, VCR and CTX all increased as comparedwith their parental cell lines. The meanfluorescence intensity of ADR in AH--SGC7901,AH-SGC7901/ VCR, AH--HCC7402 and AH-Ec109was also significantly elevated (P< 0. 05).CONCLUSION Down-regulation of HsP90 couldchange cell cycle distribution and increase thedrug 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.