Evidence from microdialysis and synaptosomal studies of rat cortex for noradrenaline uptake sites with different sensitivities to SSRIs

1. Microdialysis of the frontal cortex of freely-moving rats and uptake of [3H]noradrenaline into cortical synaptosomes were used to evaluate changes in efflux of noradrenaline in vivo and uptake of [3H]noradrenaline in vitro, respectively, induced by the selective serotonin reuptake inhibitors (SSRIs), fluoxetine and citalopram, and the tricyclic antidepressant, desipramine. 2. Noradrenaline efflux was increased during local infusion into the cortex of each of these drugs. All three agents also inhibited synaptosomal uptake of [3H]noradrenaline; this inhibition was unaffected by a substantial (50%) lesion of central 5-hydroxytrytaminergic neurones induced by intracerebroventricular infusion of 5,7-DHT (150 microg). 3. A noradrenergic lesion (70%), induced by pretreatment with the selective neurotoxin, N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4, 40 mg kg(-1) i.p.), 5 days earlier, abolished the increase in noradrenaline efflux caused by local infusion of fluoxetine. In contrast, the desipramine-induced increase in efflux was greater than in non-lesioned rats whereas the effect of citalopram on noradrenaline efflux was unaffected by DSP-4 pretreatment. 4. The combined results of all these experiments suggest that there could be more than one, functionally distinct, noradrenaline uptake site in rat frontal cortex which can be distinguished by their different sensitivities to desipramine and the SSRIs, fluoxetine and citalopram.     

A novel signaling pathway controlling induced systemic resistance in Arabidopsis

Plants have the ability to acquire an enhanced level of resistance to pathogen attack after being exposed to specific biotic stimuli. In Arabidopsis, nonpathogenic, root-colonizing Pseudomonas fluorescens bacteria trigger an induced systemic resistance (ISR) response against infection by the bacterial leaf pathogen P. syringae pv tomato. In contrast to classic, pathogen-induced systemic acquired resistance (SAR), this rhizobacteria-mediated ISR response is independent of salicylic acid accumulation and pathogenesis-related gene activation. Using the jasmonate response mutant jar1, the ethylene response mutant etr1, and the SAR regulatory mutant npr1, we demonstrate that signal transduction leading to P. fluorescens WCS417r-mediated ISR requires responsiveness to jasmonate and ethylene and is dependent on NPR1. Similar to P. fluorescens WCS417r, methyl jasmonate and the ethylene precursor 1-aminocyclopropane-1-carboxylate were effective in inducing resistance against P. s. tomato in salicylic acid-nonaccumulating NahG plants. Moreover, methyl jasmonate-induced protection was blocked in jar1, etr1, and npr1 plants, whereas 1-aminocyclopropane-1-carboxylate-induced protection was affected in etr1 and npr1 plants but not in jar1 plants. Hence, we postulate that rhizobacteria-mediated ISR follows a novel signaling pathway in which components from the jasmonate and ethylene response are engaged successively to trigger a defense reaction that, like SAR, is regulated by NPR1. We provide evidence that the processes downstream of NPR1 in the ISR pathway are divergent from those in the SAR pathway, indicating that NPR1 differentially regulates defense responses, depending on the signals that are elicited during induction of resistance.     

Evaluation of the aortic root by MRI: insights from patients with homozygous familial hypercholesterolemia

Hepatitis C chronically infects approximately 1.5% of Americans and is the most common clinical problem facing hepatologists. Since the virus was initially described in 1989, development of an effective therapy has been challenging. Although several different therapeutic agents have been used, no therapy has been shown to reliably eradicate the virus. Interferon-alpha, a cytokine with immunostimulatory and anti-viral properties, has become the therapy of choice for patients with chronic hepatitis C infection. Trials assessing the efficacy of interferon-alpha have characterized host and viral factors predictive of responses to treatment. A thorough understanding of these predictive factors is requisite to providing cost-effective therapeutic decisions for the patient with chronic hepatitis C infection.     

Alterations of the catalytic activities of drug-metabolizing enzymes in cultures of human liver slices

The pharmacokinetics of deramciclane (CAS 120444-78-8, EGIS-3886) was investigated in rabbits after i.v., p.o. and s.c. administration of 3 mg/kg 14C-phenyl-deramciclane. The plasma, concentration-time curves of total radioactivity, the parent compound (deramciclane) and its N-demethylated metabolite (EGIS-7056) were determined. The radioactivity level was measured by liquid scintillation technique while the concentration of the parent compound and its metabolite was determined by gas chromatography-mass spectrometry detection. The p.o. and i.v. studies were carried out on the same group of animals, while a separate group of rabbits was used for studying s.c. absorption. Deramciclane was readily absorbed after p.o. and s.c. treatment (tmax 1.0 to 1.4 h). The terminal elimination half-life (t1/2 beta) of the parent compound fell between 5.8 to 7.1 h, while that of the total radioactivity ranged from 21.6 and 26.0 h. The absolute bioavailability of deramciclane calculated from the AUC0-infinity values was found to be 43 and 60% after p.o. and s.c. treatment. The apparent volume of distribution (Vd) and the whole body clearance (Cl) of deramciclane after i.v. administration were 25.0 +/- 7.1 l/kg and 2.6 +/- 0.5 l/h/kg, respectively. The AUC0-infinity values of the parent compound varied between 4.6 and 7.9% of that of total radioactivity, suggesting that deramciclane was subjected to intensive metabolic conversion. The AUC0-infinity of N-desmethyl-deramciclane was 5.7%, compared to that of the parent compound after i.v. administration.     

The prevalence of hepatitis C in patients admitted with acute hepatitis to Fairfield Infectious Diseases Hospital, 1971-1975

OBJECTIVE: To identify and determine trends in the prevalence of hepatitis C virus (HCV) antibody in stored sera from 1971 to 1975 and to determine associations with HCV seropositivity, including markers for other hepatitis infections and possible routes of transmission. DESIGN: A retrospective cross-sectional study. PATIENTS AND SETTING: 1511 adults admitted to Fairfield Infectious Diseases Hospital, Victoria, with a clinical and biochemical diagnosis of hepatitis between 1 January 1971 and 31 December 1975. MAIN OUTCOME MEASURES: Prevalence over study period of hepatitis A virus antibody (anti-HAV) IgM, hepatitis B core antibody (anti-HBc), hepatitis B surface antigen (HBsAg) and hepatitis C virus antibody (anti-HCV) in stored sera; sociodemographic data and risk factors for blood-borne viruses documented in original medical records. RESULTS: Anti-HCV was detected in 17% of adults admitted with hepatitis from 1971 through 1975. Prevalence increased significantly over this period. Most cases were in young men who had a history of injecting drug use. HCV seropositivity was also significantly associated with markers for hepatitis B infection. CONCLUSIONS: Given the 20-30-year period between infection with hepatitis and the development of liver disease, our findings predict significant liver-related morbidity in Australia in the next decade. The increase in prevalence over the five years studied suggests rapid spread of HCV through susceptible populations, principally injecting drug users.     

Multiple sample PCR amplification and electrophoretic analysis on a microchip

Polymerase chain reactions (PCRs) were carried out on as many as four DNA samples at a time on a microchip device. The PCR products were then analyzed, either individually or together on the same device, by microchip gel electrophoresis. A standard PCR protocol was used to amplify 199- and 500-base pair (bp) regions of bacteriophage lambda DNA and 346- and 410-bp regions of E. coli genomic and plasmid DNAs, respectively. Thermal lysis of the bacteria was integrated into the PCR cycle. A product sizing medium, poly(dimethylacrylamide), and an intercalating dye for fluorescence detection were used in the electrophoretic analysis of the products. PCR product sizes were determined by coelectrophoresis with marker DNA.     

NMR structure and mutagenesis of the FADD (Mort1) death-effector domain

When activated, membrane-bound receptors for Fas and tumour-necrosis factor initiate programmed cell death by recruiting the death domain of the adaptor protein FADD to the membrane. FADD then activates caspase 8 (also known as FLICE or MACH) through an interaction between the death-effector domains of FADD and caspase 8. This ultimately leads to the apoptotic response. Death-effector domains and homologous protein modules known as caspase-recruitment domains have been found in several proteins and are important regulators of caspase (FLICE) activity and of apoptosis. Here we describe the solution structure of a soluble, biologically active mutant of the FADD death-effector domain. The structure consists of six antiparallel, amphipathic alpha-helices and resembles the overall fold of the death domains of Fas and p75. Despite this structural similarity, mutations that inhibit protein-protein interactions involving the Fas death domain have no effect when introduced into the FADD death-effector domain. Instead, a hydrophobic region of the FADD death-effector domain that is not present in the death domains is vital for binding to FLICE and for apoptotic activity.     

Determination of ginsenoside Rf and Rg2 from Panax ginseng using enzyme immunoassay

We have developed an enzyme immunoassay (EIA) to quantify trace amounts of ginsenoside Rf (Rf), one of the glycosides of protopanaxatriol from Panax ginseng. A carrier protein of bovine serum albumin (BSA) was coupled to the carbohydrate component of Rf using the periodate oxidation method. Antibodies were raised in rabbits using Rf-BSA conjugate as the immunogen and competitive indirect EIA was used for the determination of Rf. The working range was 0.01-10 ng per assay. The anti-Rf antiserum cross-reacted with ginsenoside Rg2 (105%), which is also a component of Panax ginseng and has a very similar chemical structure to Rf. These results suggest that the anti-Rf antiserum could also be used for the quantitation of ginsenoside Rg2 as well as ginsenoside Rf. In a comparison of EIA and HPLC the linear regression equation and correlation coefficient for the two methods were y(EIA) = 1.31x (HPLC)-11.48 and 0.98, respectively.