Mechanisms and immunological roles of apoptosis in molluscs

Molluscan defense mechanisms are regulated to innate immunity, which is largely dependent on cellular components such as hemocytes possessing phagocytic and bactericidal activities. Among immune responses, apoptosis is an indispensable process because it enables the adequate clearance of damaged, senescent and infected cells without inflammation. Available information related to the molecular mechanisms of apoptosis has been accumulated for many molluscan species during the last decade. Almost all molluscan species live in an environment that changes incessantly according to microorganisms, industrial pollutants, temperature, and salinity. Such environmental factors might directly or indirectly induce apoptosis in molluscan cells. One type of apoptotic agent, reactive oxygen intermediates (ROIs), which are produced by a stress signal or phagocytosis, triggers apoptotic cell death in molluscan hemocytes. Dysfunction of ROI-mediated hemocytic apoptosis putatively causes disease morbidity and/or mortality when molluscan organisms are infected by pathogens. Furthermore, integrins have attracted attention for their unique functions because integrins regulate the phagocytic ability of molluscan hemocytes and induce hemocytic apoptosis. That process might be the result of ROI-generation. In this review, we summarize the roles and molecular mechanisms of apoptosis related to immunological functions of molluscan hemocytes.     

Low-affinity transport of FITC-albumin in alveolar type II epithelial cell line RLE-6TN

FITC-albumin uptake by cultured alveolar type II epithelial cells, RLE-6TN, is mediated by high- and low-affinity transport systems. In this study, characteristics of the low-affinity transport system were evaluated. The uptake of FITC-albumin was time and temperature dependent and was inhibited by metabolic inhibitors and bafilomycin A1. Confocal laser scanning microscopic analysis showed punctate localization of the fluorescence in the cells, which was partly localized in lysosomes. FITC-albumin taken up by the cells gradually degraded over time, as shown by fluoroimage analyzer after SDS-PAGE. The uptake of FITC-albumin by RLE-6TN cells was not inhibited by caveolae-mediated endocytosis inhibitors such as nystatin, but was inhibited by clathrin-mediated endocytosis inhibitors such as phenylarsine oxide. The uptake was also inhibited by potassium depletion and hypertonicity, conditions known to inhibit clathrin-mediated endocytosis. In addition, macropinocytosis inhibitors such as 5-(N-ethyl-N-isopropyl) amiloride inhibited the uptake. These results indicate that the low-affinity transport of FITC-albumin in RLE-6TN cells is at least in part mediated by clathrin-mediated endocytosis, but not by caveolae-mediated endocytosis. Possible involvement of macropinocytosis was also suggested.     

Suppression of dopamine-related side effects of morphine by aripiprazole, a dopamine system stabilizer

Dopamine receptor antagonists are commonly used to counter the adverse effects of opioids such as hallucinations, delusions and emesis. However, most of these agents themselves have side effects, including extrapyramidal symptoms. Here, we investigated the effect of the dopamine system stabilizer aripiprazole on morphine-induced dopamine-related actions in mice. Morphine-induced hyperlocomotion and reward were significantly suppressed by either the dopamine receptor antagonist prochlorperazine or aripiprazole. Catalepsy was observed with a high dose of prochlorperazine, but not with an even higher dose of aripiprazole. The increased level of dialysate dopamine in the nucleus accumbens stimulated by morphine was significantly decreased by pretreatment with aripiprazole. These results suggest that the co-administration of aripiprazole may be useful for reducing the severity of morphine-induced dopamine-related side effects.     

Comparative study of aryl hydrocarbon receptor ligand activities of six chemicals in vitro and in vivo

The aryl hydrocarbon receptor (AhR) ligand activities of six known AhR ligands were compared in vivo and in vitro. The in vivo ligand activity was estimated in terms of induction of cytochrome P450 1A1/2 activities, i.e., ethoxyresorufin-O-dealkylase (EROD) and methoxyresorufin-O-dealkylase (MROD) activities, and in vitro ligand activity was evaluated with a recombinant yeast reporter gene assay. The test chemicals were 3-methylcholanthrene (MC), β-naphthoflavone (β-NF), indirubin, indigo, 3,3′-diindolylmethane (DIM) and diphenyl-p-phenylenediamine (DPPD). The first four showed potent AhR ligand activity in vitro, comparable with that of 2,3,7,8-tetrachlorodibenzo-p-dioxin, while DIM and DPPD showed weaker activity. Administration of MC and β-NF to mice caused significant induction of EROD and MROD activities, while indirubin, indigo and DIM also induced these activities, but less potently. DPPD also induced the activities, but was toxic at higher doses. These enhancing effects were lost or greatly reduced in Ahr-null mice (Ahr ^−/−). Our results suggest that EROD and MROD activity assays are useful for evaluating the AhR ligand activity of chemicals in vivo, where the biodynamics of the chemicals plays an important role.     

PK/PD breakpoints and clinical/bacteriological effects of cefcapene pivoxil fine granules for children at free drug concentrations in pediatric patients with respiratory infection

A post-marketing clinical study was previously conducted in pediatric patients with respiratory infection to evaluate the pharmacokinetics, efficacy and safety of cefcapene pivoxil (CFPN-PI) fine granules for children. Based on the results from this study, we evaluated PK/PD breakpoints and clinical/bacteriological effects of CFPN-PI at free drug concentrations in pediatric patients with respiratory infection to determine an effective and safe dosage regimen of CFPN-PI. The following results were obtained from 61 pediatric patients evaluated in our research. 1) The response rate of pediatric respiratory infection to CFPN-PI was 100% for laryngopharyngitis, 84.6% for acute bronchitis, 100% for tonsillitis, 100% for pneumonia and 95.8% for all. 2) The bacteriological response (eradication rate of Haemophilus influenzae, Streptococcus pyogenes, Moraxella catarrhalis, Streptococcus pneumoniae, etc.) of pediatric respiratory infection to CFPN-PI was 87.5% for laryngopharyngitis, 66.7% for acute bronchitis, 75.0% for tonsillitis, 63.6% for pneumonia and 73.8% for all. 3) The blood concentration simulation demonstrated that the PK/PD breakpoint exceeding the time above MIC (TAM) of 40% after administration of CFPN-PI 3 mg/kg three times daily was 0.27 microg/mL. 4) The pediatric patients with respiratory infection were stratified by the TAM (%) of CFPN-PI into 40% to 100% (TAM > or = 40% group) and 0% to 40% (TAM < 40% group) to compare the clinical and bacteriological effects of CFPN-PI. The clinical and bacteriological response rates, respectively, were 97.4% and 77.8% in the TAM > or = 40% group, and 88.9% and 62.5% in the TAM < 40% group. There was no difference in the clinical effect between the two TAM-stratified groups. On the other hand, the bacteriological effect, i.e., eradication rate, tended to be higher in the TAM > or = 40% group than in the TAM < 40% group, although the between-group difference was not statistically significant.     

Normal values and standardization of parameters in nuclear cardiology: Japanese Society of Nuclear Medicine working group database

As a 2-year project of the Japanese Society of Nuclear Medicine working group activity, normal myocardial imaging databases were accumulated and summarized. Stress-rest with gated and non-gated image sets were accumulated for myocardial perfusion imaging and could be used for perfusion defect scoring and normal left ventricular (LV) function analysis. For single-photon emission computed tomography (SPECT) with multi-focal collimator design, databases of supine and prone positions and computed tomography (CT)-based attenuation correction were created. The CT-based correction provided similar perfusion patterns between genders. In phase analysis of gated myocardial perfusion SPECT, a new approach for analyzing dyssynchrony, normal ranges of parameters for phase bandwidth, standard deviation and entropy were determined in four software programs. Although the results were not interchangeable, dependency on gender, ejection fraction and volumes were common characteristics of these parameters. Standardization of ¹²³I-MIBG sympathetic imaging was performed regarding heart-to-mediastinum ratio (HMR) using a calibration phantom method. The HMRs from any collimator types could be converted to the value with medium-energy comparable collimators. Appropriate quantification based on common normal databases and standard technology could play a pivotal role for clinical practice and researches.     

Validation of a simplified scatter correction method for 3D brain PET with <Superscript>15</Superscript>O

Objective

Positron emission tomography (PET) enables quantitative measurements of various biological functions. Accuracy in data acquisition and processing schemes is a prerequisite for this. The correction of scatter is especially important when a 3D PET scanner is used. The aim of this study was to validate the use of a simplified calculation-based scatter correction method for ¹⁵O studies in the brain.

Methods

We applied two scatter correction methods to the same ¹⁵O PET data acquired from patients with cerebrovascular disease (n = 10): a hybrid dual-energy-window scatter correction (reference method), and a deconvolution scatter correction (simplified method). The PET study included three sequential scans for ¹⁵O-CO, ¹⁵O-O₂, and ¹⁵O-H₂O, from which the following quantitative parameters were calculated, cerebral blood flow, cerebral blood volume, cerebral metabolic rate of oxygen, and oxygen extraction fraction.

Results

Both scatter correction methods provided similar reconstruction images with almost identical image noise, although there were slightly greater differences in white-matter regions compared with gray matter regions. These differences were also greater for ¹⁵O-CO than for ¹⁵O-H₂O and ¹⁵O-O₂. Region of interest analysis of the quantitative parameters demonstrated that the differences were less than 10 % (except for cerebral blood volume in white-matter regions), and the agreement between the methods was excellent, with intraclass correlation coefficients above 0.95 for all the parameters.

Conclusions

The deconvolution scatter correction despite its simplified implementation provided similar results to the hybrid dual-energy-window scatter correction. We consider it suitable for application in a clinical ¹⁵O brain study using a 3D PET scanner.

     

Reversible sclerosing cholangitis with ulcerative colitis

Sclerosing cholangitis (SC) with granulocytic epithelial lesion (GEL) responds well to immunosuppression therapy. We treated a 42‐year‐old Japanese female with ulcerative colitis, who was admitted for further evaluation of both an elevated alkaline phosphatase level and dilated intrahepatic bile ducts. A liver biopsy on the fourth hospital day revealed the infiltration of neutrophils into the bile duct epithelium, which was diagnosed as GEL. Because her ulcerative colitis was in an active stage, prednisolone (PSL) therapy was started. After the administration of PSL, laboratory data dramatically decreased. A liver biopsy was performed on the 66th hospital day to confirm the lesion around bile ducts in the portal tract. The infiltration of neutrophils into the bile duct epithelium disappeared after PSL administration, and IgG4‐positive plasma cells were not found in the liver. Herein, we report a rare case of GEL‐positive SC. The present case provides early evidence of treatment‐induced histological changes as well as serial changes in biochemical data during the course of immunosuppression therapy.