Excised porcine skin experimental systems to validate quantitative microdialysis methods for determination of drugs in skin after topical application.

Microdialysis is useful as a method to evaluate the disposition of drugs in the skin to design improved transdermal delivery systems (TDDSs). In this study, quantitative microdialysis methods were validated in excised porcine skin experimental systems in vitro. Flurbiprofen (FP), used as a model drug, showed high affinity for the skin tissues in equilibrium states between the medium and skin. The membrane clearances of FP for permeation through the membrane of a dialysis fiber placed in the skin (CL(m in S)) were lower than that in the medium. The adsorption of components in the skin to the membrane surface of the dialysis fiber and accumulation of FP near the dialysis fiber are the most likely reasons for this. When CL(m in S) was used to predict the extracellular FP concentration in skin (C(T)), the value obtained was lower than that expected from the FP concentration in the medium on the dermis side, which should be equal to C(T) at equilibrium. In the zero net flux (ZNF) method, in which the concentration difference of perfusate (DeltaC) between the inflow and outflow were used to obtain C(T), the predicted C(T) was similar to the expected value. In an in vitro skin permeation experiment, the ZNF method was used for the prediction of C(T) near the dialysis fiber. The predicted C(T) was over 10 times higher than the FP concentration in the medium on the dermis side, suggesting a concentration gradient in the dermis. Although the ZNF method is good for predicting the C(T) in skin, the mass balance has to be considered for the quantitative evaluation of the skin permeation of drugs. In this study, the effect of the mass transfer of FP from the perfusate to the skin on the cumulative amount of FP passing through the skin was relatively low because of the use of suitable solutions as perfusate. The perfusion conditions and schedules should be designed carefully for quantitative evaluations using the ZNF method. These results provide useful information for the in vivo application of quantitative microdialysis to evaluate TDDS.     

In vivo imaging of mitochondrial function in methamphetamine-treated rats

Abuse of the powerfully addictive psychostimulant, methamphetamine, occurs worldwide. Recent studies have suggested that methamphetamine-induced dopaminergic neurotoxicity is related to oxidative stress. In response to nerve activation, the mitochondrial respiratory chain is rapidly activated. The enhancement of mitochondrial respiratory chain activation may induce oxidative stress in the brain. However, there is little experimental evidence regarding the mitochondrial function after methamphetamine administration in vivo. Here, we evaluated whether a single administration of methamphetamine induces ATP consumption and overactivation of mitochondria. We measured mitochondrial function in two different ways: by monitoring oxygen partial pressure using an oxygen-selective electrode, and by imaging of redox reactions using a nitroxyl radical (i.e., nitroxide) coupled with Overhauser-enhanced magnetic resonance imaging (OMRI). A single administration of methamphetamine to Wistar rats induced dopaminergic nerve activation, ATP consumption and an increase in mitochondrial respiratory chain function in both the striatum and cortex. Furthermore, antioxidant TEMPOL prevented the increase in mitochondrial oxidative damage and methamphetamine-induced sensitization. These findings suggest that energy-supplying reactions after dopaminergic nerve activation are associated with oxidative stress in both the striatum and cortex, leading to abnormal behavior.     

Portal tumor thrombus secondary to gastric carcinoma: report of a case with an emphasis on color Doppler ultrasound findings

We report the case of a 67-year-old woman with portal tumor thrombus (PTT) associated with gastric carcinoma. Abdominal ultrasound (US) revealed a marked thickening of the gastric wall and a mass lesion in the splenic vein. Color Doppler US showed the intraportal mass to be blood flow-poor and revealed a gastroepiploic vein extending from the splenic hilum to the portal confluence, passing behind the peritoneum. These findings corresponded well with gastric carcinoma with PTT. Endoscopy confirmed the presence of an advanced type II carcinoma predominantly located in the upper body, which yielded histological results consistent with a well-differentiated adenocarcinoma. The patient's general condition deteriorated rapidly, and she died 2 months later. To the best of our knowledge, this is the first report describing the presence of a large gastroepiploic vein secondary to gastric carcinoma-associated PTT.     

Effects of selective LDL apheresis on plasma concentrations of ICAM-1, VCAM-1 and P-selectin in diabetic patients with arteriosclerosis obliterans and receiving maintenance hemodialysis

BACKGROUND: Arteriosclerosis obliterans (ASO) is a serious complication in patients with end-stage renal disease (ESRD) caused by diabetic nephropathy. Adsorption of low-density lipoprotein (LDL) has been performed to treat ASO. While efficacy of this treatment has been reported in limb ischemia, the mechanism underlying the benefit remains unclear. We investigated how LDL adsorption affected soluble adhesion molecules; P-selectin, an endothelial and platelet activation marker; inflammatory cytokines such as interleukin (IL)-1beta, IL-6 and tissue necrosis factor (TNF)-alpha; and lipids in serum. METHODS: Selective LDL adsorption by dextran sulfate columns (LDL apheresis) was performed weekly for 10 weeks to treat eight hemodialysis patients with ASO, ESRD, and type 2 diabetes mellitus. Serum was sampled before and immediately after apheresis. RESULTS: LDL apheresis was performed safely. After LDL apheresis lipid concentrations were significantly reduced and clinical findings, such as Fontaine's classification and ankle brachial pressure index values, were improved. Pretreatment concentrations of soluble intercellular and vascular cell adhesion molecules (sICAM-1 and sVCAM-1) and also P-selectin were higher in patients than healthy controls. After apheresis these decreased, especially P-selectin. IL-1beta, IL-6, and TNF-alpha concentrations before apheresis were similar to those in controls and were unaffected by treatment. CONCLUSION: Effectiveness of LDL apheresis against ASO may involve decreased endothelial cell and platelet activation.     

Altered Ribosomes in Antibiotic-Resistant Mutants of Mycobacterium smegmatis

Two alleles for viomycin-capreomycin resistance (vic) in Mycobacterium smegmatis affect ribosome structures. One (vicA) affects a component of 50S subunits and the other (vicB) affects a component of 30S subunits. The locus for neomycin-kanamycin resistance (nek), which is linked to vicA and vicB, affects a component of 30S subunits. Although the erythromycin resistance locus (ery) is linked to vic and nek, no ribosomal alterations could be detected. Mutations at the streptomycin locus (str) not linked to vic and nek caused alterations of 30S subunits.     

Cux2 activity defines a subpopulation of perinatal neurogenic progenitors in the hippocampus

The hippocampus arises from the medial region of the subventricular (SVZ) within the telencephalon. It is one of two regions in the postnatal brain that harbors neural progenitors (NPs) capable of giving rise to new neurons. Neurogenesis in the hippocampus is restricted to the subgranular zone (SGZ) of the dentate gyrus (DG) where it contributes to the generation of granule cell layer (gcl) neurons. It is thought that SGZ progenitors are heterogeneous, differing in their morphology, expression profiles, and developmental potential, however it is currently unknown whether they display differences in their developmental origins and cell fate‐restriction in the DG. Here we demonstrate that Cux2 is a marker for SGZ progenitors and nascent granule cell neurons in the perinatal brain. Cux2 was expressed in the presumptive hippocampal forming region of the embryonic forebrain from E14.5 onwards. At fetal stages, Cux2 was expressed in early‐forming Prox1⁺ granule cell neurons as well as the SVZ of the DG germinal matrix. In the postnatal brain, Cux2 was expressed in several types of progenitors in the SGZ of the DG, including Nestin/Sox2 double‐positive radial glia, Sox2⁺ cells that lacked a radial glial process, DCX⁺ neuroblasts, and Calretinin‐expressing nascent neurons. Another domain characterized by a low level of Cux2 expression emerged in Calbindin⁺ neurons of the developing DG blades. We used Cux2‐Cre mice in genetic fate‐mapping studies and showed almost exclusive labeling of Calbindin‐positive gcl neurons, but not in any progenitor cell types or astroglia. This suggests that Cux2⁺ progenitors directly differentiate into gcl neurons and do not self‐renew. Interestingly, developmental profiling of cell fate revealed an outside‐in formation of gcl neurons in the DG, likely reflecting the activity of Cux2 in the germinative matrices during DG formation and maturation. However, DG morphogenesis proceeded largely normally in hypomorphic Cux2 mutants lacking Cux2 expression. Taken together we conclude that Cux2 expression reflects hippocampal neurogenesis and identifies non‐self‐renewing NPs in the SGZ. © 2014 The Authors Hippocampus Published by Wiley Periodicals, Inc.