HLA and hypocretin studies in Korean patients with narcolepsy

STUDY OBJECTIVES: Very few studies have evaluated narcolepsy in Asian countries, outside of Japan. Our goal was to study narcolepsy at the genetic, clinical and pathophysiological level in Korea. DESIGN: Prospective study of consecutive patients and age matched controls. Clinical data ascertained from the Stanford Sleep Inventory, Polysomnography and MSLT data, as well as clinical notes. High resolution DRB1 and DQB1 typing in all subjects and studies of CSF hypocretin-1 was also evaluated in a subset of patients. PARTICIPANTS AND SETTING: 20 patients diagnosed at St. Vincent and Korea University Hospitals (Seoul, Korea). 21 Korean control subjects. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: For narcoleptic subjects, mean age was 28.2 years old and 45% were female. Mean BMI was 23.9+/-3.4 kg/m2, a significantly higher value than that expected in an age- and sex-matched sample (p<0.01). All patients had sleepiness and cataplexy while the prevalence of other symptoms ranged from 60-75%. All but 2 subjects were HLA-DR15 (DR2), DQB1*0602 positive (90%). This high DQB1*0602 percentage compared with 24% DQB1*0602 positivity in 21 control Koreans. Protective effects were observed for the DQB1*0601 and DRB1*0406 alleles, Hypocretin (orexin) CSF studies were also performed in 6 cataplectic subjects, all of which had undetectable CSF hypocretin levels. Two of these subjects had started narcolepsy less than 1 year before analysis yet had undetectable hypocretin levels. CONCLUSION: These results illustrate the similarity of narcolepsy-cataplexy in Korea in comparisons with other more studied populations. We also identified a new potential HLA protective subtype, HLA-DRB1*0406.     

Use of egg yolk-derived immunoglobulin as an alternative to antibiotic treatment for control of Helicobacter pylori infection

The present study evaluated the potential use of immunoglobulin prepared from the egg yolk of hens immunized with Helicobacter pylori (immunoglobulin Y [IgY]-Hp) in the treatment of H. pylori infections. The purity of our purified IgY-Hp was 91.3%, with a yield of 9.4 mg of IgY per ml of egg yolk. The titer for IgY-Hp was 16 times higher than that for IgY in egg yolk from nonimmunized hens, and IgY-Hp significantly inhibited the growth and urease activity of H. pylori in vitro. Bacterial adhesion on AGS cells was definitely reduced by preincubation of both H. pylori (10(8) CFU/ml) and 10 mg of IgY-Hp/ml. In Mongolian gerbil models, IgY-Hp decreased H. pylori-induced gastric mucosal injury as determined by the degree of lymphocyte and neutrophil infiltration. Therefore, in this experimental model, H. pylori-associated gastritis could be successfully treated by orally administered IgY-Hp. The immunological activity of IgY-Hp stayed active at 60 degrees C for 10 min, suggesting that pasteurization can be applied to sterilize the product. Fortification of food products with this immunoglobulin would significantly decrease the H. pylori infection. In conclusion, the IgY-Hp obtained from hens immunized by H. pylori could provide a novel alternative approach to treatment of H. pylori infection.     

Effects of neostigmine on the pharmacokinetics of intravenous parathion in rats

It was reported that the area under the plasma concentration-time curve from time zero to time infinity (AUC) of parathion was significantly smaller and the time-averaged total body clearance (CL) of parathion was significantly faster after intravenous administration of parathion to rats pretreated with dexamethasone than those in control rats. This was supported by significantly faster intrinsic clearance of parathion to form paraoxon in hepatic microsomal fraction of rats pretreated with dexamethasone. The above data suggested that parathion was metabolized to paraoxon by dexamethasone-inducible hepatic cytochrome P450 (CYP) 3A in rats. The purpose of this study is to explain the protective effects of neostigmine against paraoxon toxicity by suppressing CYP3A and hence decreasing formation of toxic metabolite, paraoxon by neostigmine. The pharmacokinetic changes of parathion and its active metabolite, paraoxon, were investigated after intravenous administration of parathion, 3 mg/kg, to control Sprague-Dawley rats and the rats pretreated with neostigmine (200 microg/kg, intraperitoneal injection 30 min before parathion administration). After 1-min intravenous infusion of parathion to rats pretreated with neostigmine, the AUC of parathion (65.1 versus 74.3 microg min/ml) was significantly greater and the CL of parathion (45.1 versus 40.4 ml/min/kg) was significantly slower than those in control rats. Based on in vitro hepatic microsomal studies, neostigmine inhibited significantly the erythromycin N-demethylase activity (1.03 versus 0.871 nmol/mg protein/min), mainly mediated by hepatic cytochrome P450 3A in rats. The above data suggested that the formation of paraoxon was inhibited in rats pretreated with neostigmine by inhibiting CYP3A.     

Design, testing, and clinical studies of a handheld polarized light camera

Polarized light imaging has been used to detect the borders of skin cancer and facilitate assessment of cancer boundaries. A design for an inexpensive handheld polarized camera is presented and clinical images acquired with this prototype are shown. The camera is built with two universal serial bus (USB) color video cameras, a polarizing beamsplitter cube, and a 4x objective lens. Illumination is provided by three white LEDs and a sheet polarizer. Horizontal and vertical linearly polarized reflected images are processed at 7 frames/s and a resulting polarized image is displayed on screen. We compare the performances of cheap USB camera and a 16-bit electronically cooled camera. Dark noise and image repeatability are compared. In both cases, the 16-bit camera outperforms the USB cameras. Despite these limitations, the results obtained with this USB prototype are very satisfactory. Examples of polarized images of lesions taken prior to surgery are presented.     

Germinal center formation in mice lacking αβ T cells

T cells are essential for inducing clonal B cell expansion in germinal centers during T cell-dependent antibody responses. However, class-switched antibodies are readily detectable in TCRα-deficient mice that congenitally lack αβ T cells, including those such as IgG1 that are considered to be dependent on collaboration between B cells and αβ T cells. This observation suggests that a novel form of B:T collaboration may be evident in TCRα^?/? mice. We report that germinal centers develop spontaneously in mice lacking T cell receptor α genes (TCRα^?/?), despite the absence of αβ T cells. They are not seen in TCRβ^?/? mice kept in similar conditions. Both strains of mice have γδ T cells, but it is a subset of T cells expressing TCRβ and CD4 that is dominant in the germinal centers of TCRα^?/? mice. Exceptionally, germinal centers were associated with CD4⁺ γδ T cells. The expression of CD4 seems to be important, for few extrafollicular T cells have CD4 and CD4 is largely absent from TCRβ^?/? T cells. The CD4⁺ TCRβ cells may help B cells produce autoantibodies that have been identified in TCRα^?/? mice.     

Changing seroepidemiology of hepatitis B, C, and D virus infections in high-risk populations

Needle-sharing and sexual contact are important transmission routes of hepatitis B, C, and D virus (HBV, HCV, HDV) infection. This study aimed to investigate the current status of these viral infections among high-risk populations including prostitutes and intravenous (i.v.) drug users, compared with the prevalence rate reported previously to examine the changing seroepidemiology. Of the 916 female prostitutes, 79 (9%) were positive for antibody to HCV (anti-HCV), 111 (12%) were positive for HBV surface antigen (HBsAg), and 5 (5%) had antibody to HDV (anti-HDV). The prevalence rate was significantly lower compared to that in 1989-1991 (12%, P = 0.037) for HCV infection, and to that in 1988 (59%) and 1996 (40%) (P < 0.0001) for HDV infection. Of the 494 i.v. drug users, 87 (18%) patients were HBsAg carriers and 12 (14%) were anti-HDV-positive. The prevalence rate of HDV infection was significantly lower than that reported in 1985 (79%, P < 0.0001). Among the 443 tested i.v. drug users, 182 (41%) were anti-HCV-positive, significantly lower than that in 1985 (53%, P = 0.026). Of the 263 male prostitutes, 11 (4%) were anti-HCV-positive, 45 (17%) were HBsAg-positive, and 7 (16%) were anti-HDV-positive. Of the 129 illegal immigrant prostitutes, 7 (5%) were anti-HCV-positive, 15 (12%) were HBsAg-positive and none were positive for anti-HDV. In conclusion, the findings indicate a declining prevalence of HCV and HDV infections among drug users and prostitutes over the past 16 years. Male prostitutes and immigrant prostitutes are new "high-risk" populations and may become a reservoir for disease transmission.     

Escherichia coli and Staphylococcus aureus elicit differential innate immune responses following intramammary infection

Staphylococcus aureus and Escherichia coli are among the most prevalent species of gram-positive and gram-negative bacteria, respectively, that induce clinical mastitis. The innate immune system comprises the immediate host defense mechanisms to protect against infection and contributes to the initial detection of and proinflammatory response to infectious pathogens. The objective of the present study was to characterize the different innate immune responses to experimental intramammary infection with E. coli and S. aureus during clinical mastitis. The cytokine response and changes in the levels of soluble CD14 (sCD14) and lipopolysaccharide-binding protein (LBP), two proteins that contribute to host recognition of bacterial cell wall products, were studied. Intramammary infection with either E. coli or S. aureus elicited systemic changes, including decreased milk output, a febrile response, and induction of the acute-phase synthesis of LBP. Infection with either bacterium resulted in increased levels of interleukin 1beta (IL-1beta), gamma interferon, IL-12, sCD14, and LBP in milk. High levels of the complement cleavage product C5a and the anti-inflammatory cytokine IL-10 were detected at several time points following E. coli infection, whereas S. aureus infection elicited a slight but detectable increase in these mediators at a single time point. Increases in IL-8 and tumor necrosis factor alpha were observed only in quarters infected with E. coli. Together, these data demonstrate the variability of the host innate immune response to E. coli and S. aureus and suggest that the limited cytokine response to S. aureus may contribute to the well-known ability of the bacterium to establish chronic intramammary infection.     

Image reconstruction of anisotropic conductivity tensor distribution in MREIT: computer simulation study

We describe a novel method of reconstructing images of an anisotropic conductivity tensor distribution inside an electrically conducting subject in magnetic resonance electrical impedance tomography (MREIT). MREIT is a recent medical imaging technique combining electrical impedance tomography (EIT) and magnetic resonance imaging (MRI) to produce conductivity images with improved spatial resolution and accuracy. In MREIT, we inject electrical current into the subject through surface electrodes and measure the z-component Bz of the induced magnetic flux density using an MRI scanner. Here, we assume that z is the direction of the main magnetic field of the MRI scanner. Considering the fact that most biological tissues are known to have anisotropic conductivity values, the primary goal of MREIT should be the imaging of an anisotropic conductivity tensor distribution. However, up to now, all MREIT techniques have assumed an isotropic conductivity distribution in the image reconstruction problem to simplify the underlying mathematical theory. In this paper, we firstly formulate a new image reconstruction method of an anisotropic conductivity tensor distribution. We use the relationship between multiple injection currents and the corresponding induced Bz data. Simulation results show that the algorithm can successfully reconstruct images of anisotropic conductivity tensor distributions. While the results show the feasibility of the method, they also suggest a more careful design of data collection methods and data processing techniques compared with isotropic conductivity imaging.     

Hypoxia promotes murine bone-marrow-derived stromal cell migration and tube formation

Recent evidence indicates that bone-marrow-derived stromal cells (MSCs) have a histology coherent with endothelial cells that may enable them to contribute to tumor angiogenesis through yet undefined mechanisms. In this work, we investigated the angiogenic properties of murine MSCs involved in extracellular matrix degradation and in neovascularization that could take place in a hypoxic environment such as that encountered in tumor masses. MSCs were cultured in normoxia (95% air and 5% CO(2)) or in hypoxia (1% oxygen, 5% CO(2), and 94% nitrogen). We found that hypoxic culture conditions rapidly induced MSC migration and three-dimensional capillary-like structure formation on Matrigel. In vitro, MSC migration was induced by growth-factor- and cytokine-enriched conditioned media isolated from U-87 glioma cells as well as from MSCs cultured in hypoxic conditions, suggesting both paracrine and autocrine regulatory mechanisms. Although greater vascular endothelial growth factor levels were secreted by MSCs in hypoxic conditions, this growth factor alone could not explain their greater migration. Interestingly, matrix metalloproteinase (MMP)-2 mRNA expression and protein secretion were downregulated, while those of membrane-type (MT)1-MMP were strongly induced by hypoxia. Functional inhibition of MT1-MMP by a blocking antibody strongly suppressed MSC ability to migrate and generate capillary-like structures. Collectively, these data suggest that MSCs may have the capacity to participate in tumor angiogenesis through regulation of their angiogenic properties under an atmosphere of low oxygen that closely approximates the tumor microenvironment.