Intra-articular osteoid osteoma at the elbow mimicking arthritis: a case report

Osteoid osteomas are benign, typically intracortical lesions most often affecting the diaphysis of long bones. Nocturnal pain and characteristic symptoms that are relieved by administration of non-steroidal anti-inflammatory drugs (NSAIDs) are present and can help in the diagnosis of osteoid osteoma. We report a case of 18-year-old boy with an osteoid osteoma in the olecranon fossa with an atypical clinical manifestation. The initial manifestation was arthritis-like symptoms such as local heat, motion pain rather than pain at rest, and limited range-of-motion. Notably, NSAIDs were not effective at all for relieving his symptoms. Magnetic resonance imaging showed bone marrow edema around the elbow joint. The symptoms were resistant to conservative treatments, and thus, surgical resection was required. Histopathological examination showed that the lesion consisted of woven bones and osteoid tissues that anastomosed with each other. Combined with a tumor size that was less than 2 cm, clinicopathologically, the tumor was diagnosed as an osteoid osteoma. The pain was immediately relieved after the operation, and range-of-motion recovered at 2 months postoperatively. At 1 year after the surgery, the patient did not exhibit recurrence of the tumor or exacerbation of elbow pain and had a full range of elbow motion. Osteoid osteoma should be considered for the differential diagnosis of arthritis of the elbow in patients who are adolescents and young adults, which is the peak age of onset for osteoid osteoma.

Angiosarcoma after revision total knee arthroplasty

BACKGROUND

Hemarthrosis after total knee arthroplasty (TKA) is a relatively rare complication. Although most cases are effectively treated with conservative therapy, some cases require angiographic embolization or surgical intervention. Angiosarcoma is a rare malignant tumor derived from the vascular endothelium with neovascular hyperplasia and mainly arises in the skin and superficial soft tissue, and less frequently in deep soft tissue and bone. Although malignant neoplasms such as angiosarcoma in the vicinity of orthopedic implants were reported, the causal relationship between development of the malignant tumor and the orthopedic implant is widely debated in the literature.

CASE PRESENTATION

We report the case of a 68-year-old female with angiosarcoma that developed in the knee joint 2 years after revision TKA. The patient exhibited severe persistent bleeding, which reached 1000-1400 ml per day for 4 months. Histological analysis of the synovial tissue in the knee joint showed large cells with nuclear atypia. Immunohistochemical staining showed cells that were positive for CD31, CD34, and D2-40, and she was diagnosed with angiosarcoma. The patient underwent an amputation at the level of the thigh, and her general condition immediately improved after the operation. The patient did not exhibit bleeding from the site of amputation, and no local recurrence or distant metastases were detected 1 year after the amputation.

CONCLUSIONS

To the best of our knowledge, this represents the first report of angiosarcoma 2 years after revision TKA. Further careful follow up is needed, given the high-grade malignancy.

Stimulation of glycolysis promotes cardiomyocyte proliferation after injury in adult zebrafish

Cardiac metabolism plays a crucial role in producing sufficient energy to sustain cardiac function. However, the role of metabolism in different aspects of cardiomyocyte regeneration remains unclear. Working with the adult zebrafish heart regeneration model, we first find an increase in the levels of mRNAs encoding enzymes regulating glucose and pyruvate metabolism, including pyruvate kinase M1/2 (Pkm) and pyruvate dehydrogenase kinases (Pdks), especially in tissues bordering the damaged area. We further find that impaired glycolysis decreases the number of proliferating cardiomyocytes following injury. These observations are supported by analyses using loss-of-function models for the metabolic regulators Pkma2 and peroxisome proliferator-activated receptor gamma coactivator 1 alpha. Cardiomyocyte-specific loss- and gain-of-function manipulations of pyruvate metabolism using Pdk3 as well as a catalytic subunit of the pyruvate dehydrogenase complex (PDC) reveal its importance in cardiomyocyte dedifferentiation and proliferation after injury. Furthermore, we find that PDK activity can modulate cell cycle progression and protrusive activity in mammalian cardiomyocytes in culture. Our findings reveal new roles for cardiac metabolism and the PDK-PDC axis in cardiomyocyte behavior following cardiac injury.

Search for Electron Antineutrino Appearance in a Long-Baseline Muon Antineutrino Beam

Electron antineutrino appearance is measured by the T2K experiment in an accelerator-produced antineutrino beam, using additional neutrino beam operation to constrain parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. T2K observes 15 candidate electron antineutrino events with a background expectation of 9.3 events. Including information from the kinematic distribution of observed events, the hypothesis of no electron antineutrino appearance is disfavored with a significance of 2.40σ and no discrepancy between data and PMNS predictions is found. A complementary analysis that introduces an additional free parameter which allows non-PMNS values of electron neutrino and antineutrino appearance also finds no discrepancy between data and PMNS predictions.

Metabolic modulation regulates cardiac wall morphogenesis in zebrafish

During cardiac development, cardiomyocytes form complex inner wall structures called trabeculae. Despite significant investigation into this process, the potential role of metabolism has not been addressed. Using single cell resolution imaging in zebrafish, we find that cardiomyocytes seeding the trabecular layer actively change their shape while compact layer cardiomyocytes remain static. We show that Erbb2 signaling, which is required for trabeculation, activates glycolysis to support changes in cardiomyocyte shape and behavior. Pharmacological inhibition of glycolysis impairs cardiac trabeculation, and cardiomyocyte-specific loss- and gain-of-function manipulations of glycolysis decrease and increase trabeculation, respectively. In addition, loss of the glycolytic enzyme pyruvate kinase M2 impairs trabeculation. Experiments with rat neonatal cardiomyocytes in culture further support these observations. Our findings reveal new roles for glycolysis in regulating cardiomyocyte behavior during cardiac wall morphogenesis.

Abstract 602: Mir-182-5p is a Conserved Downstream Effector of Tbx5 Involved in Heart Development and Arrhythmia in Zebrafish

Background: TBX5 mutations cause Holt-Oram syndrome (HOS) characterized by upper limb and cardiac malformations, but can also contribute to early-onset of atrial fibrillation. Focusing on miRNAs involved in TBX5 regulatory circuits with a cardiac relevant role, we identified miR-182-5p, belonging to miR-183 cluster, found upregulated in Tbx5-depleted hearts of mouse and zebrafish embryos.

Methods: To functionally analyse the miR-182-5p role in developing heart, miR-182-5p was dysregulated in zebrafish zygotes of Tg(Myl7:EGFP) and Tg(myl7:gCaMP) transgenic lines. To stably deregulate miR-182-5p in zebrafish heart we exploited the Gal4/UAS system to restrict the miR-182 expression into cardiac context. For physiological analyses we performed the mechanogram of cardiac contraction and electrocardiogram recording. To understand miR-182-5p downstream regulation, in silico analyses, followed by ddPCR/real-time quantifications on dissected zebrafish hearts and rescue experiments both in transient and stable miR-182-5p overexpressing zebrafish embryos were performed.

Results: Depletion of Tbx5 from cardiomyocytes increased the expression of miR-182 cluster family that is controlled by Kruppel-like factor 4 (KLF4), a transcription factor repressed by Tbx5. Both transient and stable upregulation of miR-182 in zebrafish affect heart morphology, calcium handling and the onset of arrhythmia while its cardiac-specific downregulation decreases cardiac defects in zebrafish HOS hearts. Expression analyses on selected miR-182-5p putative targets revealed that several calcium channel proteins resulted downregulated in miR-182-5p overexpressing hearts. Transgenic zebrafish line stably overexpressing miR-182-5p in the heart manifested arrhythmia overtime with or without cardiac structural defects.

Conclusion: We identified miR-182-5p as a potential suitable target to interfere in the circuit between upstream genetic abnormalities and downstream effectors leading to arrhythmia occurrence.

Focal adhesions are essential to drive zebrafish heart valve morphogenesis

Gunawan et al. analyze at single-cell resolution collective endocardial cell migration into the extracellular matrix and the cellular rearrangements forming leaflets during zebrafish heart valve formation. They show that focal adhesion activity driven by Integrin α5β1 and Talin1 are essential to drive cardiac valve morphogenesis in zebrafish.

Elucidating the morphogenetic events that shape vertebrate heart valves, complex structures that prevent retrograde blood flow, is critical to understanding valvular development and aberrations. Here, we used the zebrafish atrioventricular (AV) valve to investigate these events in real time and at single-cell resolution. We report the initial events of collective migration of AV endocardial cells (ECs) into the extracellular matrix (ECM), and their subsequent rearrangements to form the leaflets. We functionally characterize integrin-based focal adhesions (FAs), critical mediators of cell–ECM interactions, during valve morphogenesis. Using transgenes to block FA signaling specifically in AV ECs as well as loss-of-function approaches, we show that FA signaling mediated by Integrin α5β1 and Talin1 promotes AV EC migration and overall shaping of the valve leaflets. Altogether, our investigation reveals the critical processes driving cardiac valve morphogenesis in vivo and establishes the zebrafish AV valve as a vertebrate model to study FA-regulated tissue morphogenesis.

Characterizing Adversity of Lysosomal Accumulation in Nonclinical Toxicity Studies: Results from the 5th ESTP International Expert Workshop

Lysosomes have a central role in cellular catabolism, trafficking, and processing of foreign particles. Accumulation of endogenous and exogenous materials in lysosomes represents a common finding in nonclinical toxicity studies. Histologically, these accumulations often lack distinctive features indicative of lysosomal or cellular dysfunction, making it difficult to consistently interpret and assign adverse dose levels. To help address this issue, the European Society of Toxicologic Pathology organized a workshop where representative types of lysosomal accumulation induced by pharmaceuticals and environmental chemicals were presented and discussed. The expert working group agreed that the diversity of lysosomal accumulations requires a case-by-case weight-of-evidence approach and outlined several factors to consider in the adversity assessment, including location and type of cell affected, lysosomal contents, severity of the accumulation, and related pathological effects as evidence of cellular or organ dysfunction. Lysosomal accumulations associated with cytotoxicity, inflammation, or fibrosis were generally considered to be adverse, while those found in isolation (without morphologic or functional consequences) were not. Workshop examples highlighted the importance of thoroughly characterizing the biological context of lysosomal effects, including mechanistic data and functional in vitro readouts if available. The information provided here should facilitate greater consistency and transparency in the interpretation of lysosomal effects.

Gel Phase Formation at Resin-modified Glass-ionomer/Tooth Interfaces

Ionic bonding between polyalkenoic acid and hydroxyapatite may explain the excellent bonding retention of glass-ionomers in clinical trials. We have here investigated the extent to which the self-adhesiveness of resin-modified glass-ionomers (RMGIs) can be attributed to this chemical bonding capacity. Therefore, the interaction of 3 RMGIs with tooth substrates was comprehensively characterized, with electron and atomic force microscopy correlated with x-ray photoelectron spectroscopy (XPS). Interfacial ultrastructural analysis for 2 RMGIs disclosed a shallow hybridization of hydroxyapatite-coated collagen, on which a submicron gel phase was deposited through reaction of the polyalkenoic acid with calcium extracted from the dentin surface. One RMGI, however, bonded to dentin without hybrid layer or gel phase formation. XPS indicated that polycarboxylic acids included in the RMGIs electrostatically interacted with hydroxyapatite. We conclude that the self-adhesiveness of RMGIs should be attributed to ionic bonding to hydroxyapatite around collagen, and to micro-mechanical interlocking for those RMGIs that additionally hybridize dentin.

Comparative Study on Adhesive Performance of Functional Monomers

Mild self-etch adhesives demineralize dentin only partially, leaving hydroxyapatite around collagen within a submicron hybrid layer. We hypothesized that this residual hydroxyapatite may serve as a receptor for chemical interaction with the functional monomer and, subsequently, contribute to adhesive performance in addition to micro-mechanical hybridization. We therefore chemically characterized the adhesive interaction of 3 functional monomers with synthetic hydroxyapatite, using x-ray photoelectron spectroscopy and atomic absorption spectrophotometry. We further characterized their interaction with dentin ultra-morphologically, using transmission electron microscopy. The monomer 10-methacryloxydecyl dihydrogen phosphate (10-MDP) readily adhered to hydroxyapatite. This bond appeared very stable, as confirmed by the low dissolution rate of its calcium salt in water. The bonding potential of 4-methacryloxyethyl trimellitic acid (4-MET) was substantially lower. The monomer 2-methacryloxyethyl phenyl hydrogen phosphate (phenyl-P) and its bond to hydroxyapatite did not appear to be hydrolytically stable. Besides self-etching dentin, specific functional monomers have additional chemical bonding efficacy that is expected to contribute to their adhesive potential to tooth tissue.

zTrap: zebrafish gene trap and enhancer trap database

BACKGROUND

We have developed genetic methods in zebrafish by using the Tol2 transposable element; namely, transgenesis, gene trapping, enhancer trapping and the Gal4FF-UAS system. Gene trap constructs contain a splice acceptor and the GFP or Gal4FF (a modified version of the yeast Gal4 transcription activator) gene, and enhancer trap constructs contain the zebrafish hsp70l promoter and the GFP or Gal4FF gene. By performing genetic screens using these constructs, we have generated transgenic zebrafish that express GFP and Gal4FF in specific cells, tissues and organs. Gal4FF expression is visualized by creating double transgenic fish carrying a Gal4FF transgene and the GFP reporter gene placed downstream of the Gal4-recognition sequence (UAS). Further, the Gal4FF-expressing cells can be manipulated by mating with UAS effector fish. For instance, when fish expressing Gal4FF in specific neurons are crossed with the UAS:TeTxLC fish carrying the tetanus neurotoxin gene downstream of UAS, the neuronal activities are inhibited in the double transgenic fish. Thus, these transgenic fish are useful to study developmental biology and neurobiology.

DESCRIPTION

To increase the usefulness of the transgenic fish resource, we developed a web-based database named zTrap http://kawakami.lab.nig.ac.jp/ztrap/. The zTrap database contains images of GFP and Gal4FF expression patterns, and genomic DNA sequences surrounding the integration sites of the gene trap and enhancer trap constructs. The integration sites are mapped onto the Ensembl zebrafish genome by in-house Blat analysis and can be viewed on the zTrap and Ensembl genome browsers. Furthermore, zTrap is equipped with the functionality to search these data for expression patterns and genomic loci of interest. zTrap contains the information about transgenic fish including UAS reporter and effector fish.

CONCLUSION

zTrap is a useful resource to find gene trap and enhancer trap fish lines that express GFP and Gal4FF in desired patterns, and to find insertions of the gene trap and enhancer trap constructs that are located within or near genes of interest. These transgenic fish can be utilized to observe specific cell types during embryogenesis, to manipulate their functions, and to discover novel genes and cis-regulatory elements. Therefore, zTrap should facilitate studies on genomics, developmental biology and neurobiology utilizing the transgenic zebrafish resource.

Thoracic mass in a cynomolgus macaque (Macaca fascicularis)

A male cynomolgus macaque at the age of 3 years and 11 months suffered sudden cardiac arrest during a surgical operation. This animal had been clinically asymptomatic for 6 months from the acclimatization period to death. At necropsy, a white mass approximately 5 cm in diameter was found at the base of the heart. Histopathologically, the mass consisted of a granuloma with a number of multinucleated giant cells and multiple necrotic foci. Fungal hyphae characterized by parallel cell walls, distinct septa, and branching were observed in the lesion. The granuloma extended into the thoracic lymph nodes and the subepicardium of the left atrium, compressed the bronchioli, and was separated from the pulmonary parenchyma by a thick fibrous layer. The hyphal morphology and results of polymerase chain reaction assays demonstrated that the pathogen was Aspergillus sp.

Analysis of Chemical Interaction of 4-MET with Hydroxyapatite Using XPS

Each dental adhesive contains a specific functional monomer that determines its actual adhesive performance to tooth tissue. 4-methacryloxyethyl trimellitic acid (4-MET) is well-known as one of the functional monomers mostly available and consequently widely used in commercial adhesives. We therefore characterized the chemical interaction of 4-MET with hydroxyapatite (HAp) using X-ray Photoelectron Spectroscopy (XPS). XPS revealed that the peak representing -COO- of 4-MET shifted to a lower binding energy, when 4-MET was adsorbed onto HAp. Deconvolution of this shifted peak disclosed two components with a peak representing unreacted carboxyl groups and ester groups, and a peak suggesting chemical bonding of other carboxyl groups to Ca of HAp. XPS spectra of HAp treated with 4-MET also disclosed the surface to be enriched in calcium and decreased in phosphorus, indicating that phosphorus was extracted at a relatively higher rate than calcium. It can thus be concluded that true chemical bonding of 4-MET with calcium present in HAp occurred, as it was proven using XPS.

Voxel-based analysis of MRI reveals anterior cingulate gray-matter volume reduction in posttraumatic stress disorder due to terrorism

MRI studies using the manual tracing method have shown a smaller-than-normal hippocampal volume in patients with posttraumatic stress disorder (PTSD). However, these studies have yielded inconsistent results, and brain structures other than the hippocampus have not been well investigated. A recently developed, fully automated method called voxel-based morphometry enables an exploration of structural changes throughout the brain by applying statistical parametric mapping to high-resolution MRI. Here we first used this technology in patients with PTSD. Participants were 9 victims of the Tokyo subway sarin attack with PTSD and 16 matched victims of the same traumatic event without PTSD. The voxel-based morphometry showed a significant gray-matter volume reduction in the left anterior cingulate cortex (ACC) in trauma survivors with PTSD compared with those without PTSD. The severity of the disorder was negatively correlated with the gray-matter volume of the left ACC in PTSD subjects. There were no significant differences in other gray-matter regions or any of the white-matter regions between two groups. The present study demonstrates evidence for structural abnormalities of ACC in patients with PTSD. Together with previous functional neuroimaging studies showing a dysfunction of this region, the present findings provide further support for the important role of ACC, which is pivotally involved in attention, emotional regulation, and conditioned fear, in the pathology of PTSD.

Bonding efficacy of polyalkenoic acids to hydroxyapatite, enamel and dentin

Previously, we introduced a methodology to determine the chemical bonding potential of polyalkenoic acids to mineralized tissues through quantification of the degree of ionic bond formation between the carboxyl groups of a polyalkenoic acid with calcium of hydroxyapatite. In a continuation of that study, we now investigated in how far the chemical bonding potential to synthetic hydroxyapatite is influenced by the molecular structure of the polyalkenoic acid and if this also may affect the self-adhesiveness to enamel and dentin. X-ray photoelectron spectroscopy and inductively coupled plasma atomic emission spectrometry were used to quantitatively analyze the chemical bonding efficacy of a polyalkenoic acid consisting of acrylic acid units (PAA) to synthetic hydroxyapatite (HAp) in comparison to the chemical bonding potential of the previously investigated synthesized polyalkenoic acid (s-PA) co-polymer consisting of 90w/w% acrylic and 10w/w% maleic acid units. In addition, the analysis was carried out for enamel and dentin samples. PAA revealed a significantly lower bonding effectiveness with only half of its carboxyl groups bonded to HAp versus about two-third of the carboxyl groups of s-PA. The difference in bonding potential was confirmed by the considerably lower adhesiveness of PAA to enamel and dentin as compared to that of s-PA The present findings indicate that the molecular structure of the polyalkenoic acid significantly influences the chemical bonding efficacy to Hap-based substrates.

1H-MR spectroscopy and gray matter volume of the anterior cingulate cortex in schizophrenia

Schizophrenic and normal control subjects were examined using both H-magnetic resonance spectroscopy (MRS) and structural MR imaging, in order to accurately assess the partial volume within the spectroscopic volume of interest (VOI) in the anterior cingulate cortex. The gray matter volume within VOI correlated positively with the N-acetyl-aspartate (NAA) to choline (Cho) ratio in schizophrenics only, not in controls. Schizophrenic patients had a reduced NAA/Cho ratio and an elevated Cho/creatine ratio compared to controls after the partial volume effect was eliminated. There was a significant negative correlation between the NAA/Cho ratio and the severity of blunted affect symptom in schizophrenics. These results provide further support to the idea that the measures of H-MRS indicate not only neuronal loss but also neuronal dysfunction in schizophrenia.

Activation of prostaglandin E2-receptor EP2 and EP4 pathways induces growth inhibition in human gastric carcinoma cell lines

The effect of prostaglandin E2 (PGE2) on the proliferation of gastric cancer cells is still unclear. PGE2 receptors are divided into four subtypes - EP1, EP2, EP3, and EP4 - which are coupled to three different intracellular signal-transduction systems. Stimulation of EP2 and EP4 is linked with cyclic adenosine 3', 5'-monophosphate (cAMP)-dependent protein kinase A (PKA). In some human gastric cancer cells, PGE2 has been suggested to have an antiproliferative effect by way of increased cAMP production. Expression of EP2 and EP4 in human gastric carcinoma cells, however, has not been examined. We examined the expression of EP2 and EP4 and the antiproliferative effects of specific EP2 and EP4 agonists on four different human gastric cancer cell lines. Our data clarified that all the cell lines investigated in this study expressed EP2 and EP4 and that the specific agonists of these receptors induced growth inhibition with an accompanying increase in cAMP production. In summary, gastric cancer cells have EP2 and EP4 receptors, and their selective activation is linked with the decreased cell proliferation.

Effects of mutation in hepatitis C virus nonstructural protein 5A on interferon resistance mediated by inhibition of PKR kinase activity in mammalian cells

The IFN-induced double-stranded RNA (dsRNA)-activated protein kinase PKR is one of the key molecules in the antiviral effects of IFN. To clarify the effects of hepatitis C virus nonstructural protein 5A (NS5A) on antiviral activity of IFN, in particular on PKR kinase activity, in mammalian cells, we established inducible NS5A-expressing cell lines derived from human osteosarcoma (Saos-2). The cells expressing NS5A derived from an IFN-resistant clone (NS5A-lb) that interacted with endogenous PKR in vitro, showed a suppressive effect on IFN function as determined by interference with vesicular stomatitis virus (VSV) infection, whereas NS5A (NS5A-2a) from an IFN-sensitive clone did not block the antiviral effect of IFN. A mutant with deletion of the IFN sensitivity determining region (ISDR) in NS5A-1b (NS5A-AISDR) also interacted with PKR and suppressed its activity in vitro. However, neither NS5A-2a nor the C-terminal truncated mutant of NS5A-1b (NS5A-deltaC) blocked PKR activity. These observations confirmed the previous report that the inhibitory effect of NS5A on IFN activity is mediated at least in part by the repression of PKR. In addition, we showed that IFN sensitivity was determined not only by the ISDR but that the involvement of the C-terminal region of NS5A-1b is important for the suppression of PKR activity.

Time-course changes of ECL cell markers in acetic acid-induced gastric ulcers in rats

BACKGROUND AND AIM

Enterochromaffin-like (ECL) cells are the major source of histamine for the regulation of gastric acid secretion, and also contain histidine decarboxylase (HDC), vesicular monoamine transporter 2 (VMAT2), and chromogranin A (CgA). Although gastric acid secretion is suppressed during ulcer healing, the role of ECL cells in that process is not yet fully understood. In the present study, we investigated the changes in ECL cell number during healing of experimental ulcers in rats.

MATERIALS AND METHODS

Seven-week-old male Wistar rats were used. Acetic acid-induced ulcers were caused by an application of 100% acetic acid to the serosal surface of the rat stomachs. At different time points following the induction (12 h-15 days), time-course changes of HDC, VMAT2, and CgA mRNA expression were investigated by Northern blot analysis. The expressions of HDC, VMAT2, and CgA were immunostained on gastric mucosal sections with ulcers.

RESULTS

HDC, VMAT2, and CgA mRNA in gastric mucosa each showed an initial marked transient decrease, followed by an increase on day 10 back to the initial value. HDC, VMAT2, and CgA-immunoreactive cells at the ulcer margin were reduced in number on day 3, compared with those in distant areas. On day 10, however, they returned to levels similar to those in distant areas.

CONCLUSION

The present study revealed a local down-regulation of HDC, VMAT2, and CgA in ECL cells at the ulcer margin. As a result, we concluded that a suppression of ECL cell activity during ulcer healing may be involved in suppressed gastric acid secretion.

Association study of C825T polymorphism of the G-protein b3 subunit gene with schizophrenia and mood disorders

Alterations of G proteins have been implicated in major psychiatric illnesses. A C825T polymorphism of a gene encoding the beta3 subunit of heterotrimeric G proteins (GNB3) was reported to be associated with several pathological conditions, such as hypertension and depressive disorder. We examined whether this polymorphism is associated with functional psychoses in a Japanese sample of 370 schizophrenics, 164 bipolars, 68 depressive patients, and 198 controls. We obtained no evidence for an association of the polymorphism with any diagnostic group.

Identification of tyrosine residues involved in ligand recognition by the phosphatidylinositol 3-kinase Src homology 3 domain: circular dichroism and UV resonance Raman studies

Src homology 3 (SH3) domains are small noncatalytic protein modules capable of mediating protein-protein interactions. We previously demonstrated that the association of a ligand peptide RLP1 (RKLPPRPSK) causes environmental and structural changes of Trp55 and some of seven Tyr residues in the phosphatidylinositol 3-kinase (PI3K) SH3 domain by circular dichroism (CD) and 235-nm excited UV resonance Raman (UVRR) spectroscopies [Okishio, N., et al. (2000) Biopolymers 57, 208-217]. In this work, the affected Tyr residues were identified as Tyr12, Tyr14, and Tyr73 by the CD analysis of a series of mutants, in which every single Tyr residue was replaced by a Phe residue. Among these three residues, Tyr14 was found to be a main contributor to the UVRR spectral change upon the RLP1 binding. Interestingly, CD and UVRR analyses revealed that RLP1 associates with the Y14F and Y14H mutants in different ways. These results suggest that Tyr14 plays a crucial role in the ligand recognition, and the amino acid substitution at Tyr14 affects the mode of PI3K SH3-ligand interaction. Our findings give an insight into how SH3 domains can produce diversity and specificity to transduce signaling within cells.

Functional magnetic resonance imaging of odor identification: the effect of aging

BACKGROUND

Sense of smell declines with age and impairment in olfaction has been observed in some neurodegenerative disorders such as Alzheimer's disease. Functional neuroimaging techniques enable researchers to observe brain regions activated by olfactory stimuli.

METHODS

We gave three mainly olfactory-mediated odors (limonene, methylsalicylate, and eugenol) to six young and six elderly subjects and observed the areas activated by using blood oxygen level dependent contrast functional magnetic resonance imaging.

RESULTS

The group mapping of young subjects showed extensive activation in the orbitofrontal cortex, commonly believed to be the olfactory cortex, some limbic areas (the hippocampus and the thalamus), regions involved with gustatory sensation (the anterior insula and the inferior postcentral gyrus), superior and inferior temporal gyri, and cerebellum. In the elderly group, only the left inferior temporal gyrus and the primary visual cortex reached accepted significance levels.

CONCLUSIONS

We have therefore confirmed previous reports of brain regions involved in olfactory processing in young volunteers and demonstrated decreased activation in elderly volunteers.

T cell-mediated cytotoxicity via Fas/Fas ligand signaling in Helicobacter pylori-infected gastric corpus

BACKGROUND

Helicobacter pylori infection induces T helper-1 immune responses in inflamed mucosa. However, the role of T cell-mediated cytotoxicity in the induction of epithelial apoptosis is still unclear. The aim of this study was to investigate the involvement of the Fas/Fas ligand (Fas/Fas-L) system in the H. pylori-infected gastric corpus.

MATERIALS AND METHODS

Gastric fundic biopsy specimens were taken from patients with and without H. pylori infection. The expression of Fas and Fas-L was examined by immunohistochemistry and RT-PCR. Subsets of gastric infiltrating T cells in the biopsy specimens were studied by immunohistochemistry and flow cytometry. In histological sections, apoptosis was detected by the TUNEL method. We studied the in vitro expression of Fas-L in peripheral T cells after stimulation with H. pylori antigen and interferon-gamma (IFN-gamma). The Fas-mediated in vitro cytotoxicity of activated T cells was assessed by flow cytometry.

RESULTS

The numbers of CD4+ and CD8+ T cells were greater in H. pylori-infected subjects. Fas expression was abundantly increased on fundic gland epithelium, and Fas-L was detected on lamina propria mononuclear cells in H. pylori-infected mucosa. TUNEL-positive epithelial cells were also increased in H. pylori-infected subjects. H. pylori antigen and IFN-gamma induced Fas-L mRNA expression in both CD4+ and CD8+ T cells. In cytotoxic assay, activated T cells induced apoptosis in AGS cells, which could be significantly inhibited by neutralizing Fas-L antibody.

CONCLUSIONS

T cell-mediated cytotoxicity via Fas/Fas-L signaling may contribute to the induction of apoptosis in gastric epithelial cells during H. pylori infection.

Activation of the Ras-cAMP signal transduction pathway inhibits the proteasome-independent degradation of misfolded protein aggregates in the endoplasmic reticulum lumen

Many kinds of misfolded secretory proteins are known to be degraded in the endoplasmic reticulum (ER). Dislocation of misfolded proteins from the ER to the cytosol and subsequent degradation by the proteasome have been demonstrated. Using the yeast Saccharomyces cerevisiae, we have been studying the secretion of a heterologous protein, Rhizopus niveus aspartic proteinase-I (RNAP-I). Previously, we found that the pro sequence of RNAP-I is important for the folding and secretion, and that Deltapro, a mutated derivative of RNAP-I in which the entire region of the pro sequence is deleted, forms gross aggregates in the yeast ER. In this study, we show that the degradation of Deltapro occurs independently of the proteasome. Its degradation was not inhibited either by a potent proteasome inhibitor or in a proteasome mutant. We also show that neither the export from the ER nor the vacuolar proteinase is required for the degradation of Deltapro. These results raise the possibility that the Deltapro aggregates are degraded in the ER lumen. We have isolated a yeast mutant in which the degradation of Deltapro is delayed. We show that the mutated gene is IRA2, which encodes a GTPase-activating protein for Ras. Because Ira2 protein is a negative regulator of the Ras-cAMP pathway, this result suggests that hyperactivation of the Ras-cAMP pathway inhibits the degradation of Deltapro. Consistently, down-regulation of the Ras-cAMP pathway in the ira2 mutant suppressed the defect of the degradation of Deltapro. Thus, the Ras-cAMP signal transduction pathway seems to control the proteasome-independent degradation of the ER misfolded protein aggregates.

Clinical relevance of precore and basal core promoter variants of hepatitis B virus during natural hepatitis B e antigen seroconversion may be overstated

BACKGROUND

Clinical relevance of nucleotide changes in precore and basal core promoters in the hepatitis B virus genome during hepatitis B e antigen seroconversion may be overstated. The authors investigated the existence and changes in the relative proportion of variants to wild virus that occur with seroconversion.

METHODS

Sera from 30 school-aged long-term hepatitis B virus carriers, including 11 tested before and after seroconversion during 1 to 8 years of follow-up, were evaluated for variations in nucleotide sequences of the basal core promoter (T1762 and A1764), precore region (A1869), and carboxyl-terminus of the X region of the hepatitis B virus genome using an amplification refractory mutation detection system with mutant-specific primers.

RESULTS

All variants were found to already exist before seroconversion at various wild-type/mutant ratios. The positive rates of these variants were not changed with loss of hepatitis B e antigen. Although there was a relative increase in the concentration of these mutants in wild-type/mutant mixed populations, most patients with only a wild-type population maintained the same pattern after loss of hepatitis B e antigen.

CONCLUSIONS

Our results indicate that hepatitis B virus exists as a quasi species, and correlations of nucleotide sequences with clinical and serologic findings must be done with caution.

Intragastric distribution of Helicobacter pylori during short-term omeprazole therapy: study using Carnoy's fixation and immunohistochemistry for detection of bacteria

BACKGROUND

There is controversy about the effect of acid-suppressive therapy on Helicobacter pylori density and the severity of histological gastritis in the corpus.

AIM

To evaluate the precise distribution of H. pylori, both on the surface mucus cells and in the surface mucus gel layer, by using Carnoy's fixation and immunostaining for the detection of bacteria.

METHODS

A total of 19 peptic ulcer patients with H. pylori infection were studied. All patients received a 6-week course of treatment with omeprazole (20 mg/day). Before and after the therapy, H. pylori density in Carnoy-fixed tissue sections was examined immunohistochemically. The effect of omeprazole therapy on the severity of gastritis was also evaluated.

RESULTS

H. pylori density and the grade of gastritis significantly decreased in the antrum after omeprazole therapy. In the corpus, however, there were no significant changes in H. pylori density or the severity of gastritis after omeprazole therapy.

CONCLUSION

Carnoy's fixation and immunostaining was found to be useful for the detection of H. pylori in the surface mucus gel layer as well as on the surface mucus cells in biopsy tissue sections. By using this method, H. pylori density decreased in the antrum, but remained unchanged in the corpus after a 6-week course of omeprazole therapy.

Collaborative work to evaluate toxicity on male reproductive organs by repeated dose studies in rats 24). Testicular toxicity of boric acid after 2- and 4-week administration periods

To assess whether or not male reproductive toxicity can be evaluated in a 2-week administration study, boric acid was administered daily by oral gavage to male Jcl:Wistar rats at dosage levels of 0, 300 and 500 mg/kg for 2 and 4 weeks, and the results obtained with the two different treatment schedules were compared. After a 2-week administration, decreased testis weights were observed in the 500 mg/kg group. Histopathologically, exfoliation of round spermatids, retention of step 19 spermatids and increased numbers of residual body-like structures in the seminiferous tubules and cell debris in the cranial epididymal ducts were observed in the 300 and 500 mg/kg groups. Distorted cytoplasmic lobes of step 19 spermatids, debris in the seminiferous tubules and focal atrophy of the seminiferous tubules with multinucleated giant cells formation and necrosis of spermatocytes were also observed in the 500 mg/kg group. After a 4-week administration, testis and epididymis weights were decreased in the 300 and 500 mg/kg groups. Histopathological changes in the 300 mg/kg group were similar to those found in the 300 and 500 mg/kg groups after a 2-week administration. Diffuse atrophy of the seminiferous tubules was additionally observed in the 500 mg/kg group. These results suggest that 2 weeks is a sufficient treatment period for the detection of the testicular toxicity caused by boric acid.

Peroxisome proliferator-activated receptor gamma ligand-induced growth inhibition of human hepatocellular carcinoma

Peroxisome proliferator-activated receptor gamma (PPARgamma) ligands have been implicated in the growth inhibition and differentiation of certain human cancers with diverse tissue origin. In this study, expression of PPARgamma in human hepatocellular carcinoma (HCC) and the effect of PPARgamma ligands on HCC cells were investigated in vitro using Hep G2, HuH-7, KYN-1 and KYN-2 cell lines. All cell lines were found to express functionally active PPARgamma and a marked growth inhibition was induced by thiazolidinedione ligands troglitazone, and pioglitazone as well as with its natural ligand 15-deoxy-Delta(12,14)-prostaglandin J(2). The growth inhibitory effect was associated with a dose-dependent inhibition of DNA synthesis, cell cycle progression and alpha fetoprotein expression.

Corpus callosum area and functioning in schizophrenic patients with auditory--verbal hallucinations

Auditory--verbal hallucinations (AVH) are a characteristic feature of schizophrenia. Patients with AVHs have been found to differ from non-hallucinating patients in volumes of certain asymmetrical brain structures on MRI, and on certain neuropsychological measures. There is also evidence of corpus callosum (CC) abnormalities in schizophrenia, and it has been proposed that abnormalities of inter-hemispheric transmission may underlie hallucinations and other symptoms. The aim of this study was to examine whether patients with AVHs have smaller corpora callosa than those without AVH, and whether CC size is related to performance on neuropsychological tests of functional cerebral asymmetry. Seventy-one DSM-IV male schizophrenics were recruited on the basis of their hallucination history plus 33 matched normal controls. Twenty-nine patients had no history of AVH, and 42 had a strong history of AVH. The mid-sagittal surface area and longitudinal length of the CC were measured from T(1)-weighted spin echo images. Callosal area was divided into four sections. There were no significant differences in any of the measurements between the two patient groups, or between patients with schizophrenia and controls. There was no association between CC measures and handedness, or performance on dichotic listening or finger tapping tasks. The results of this study do not lend support for there being a major morphological abnormality of the corpus callosum in schizophrenic patients, or for a specific relationship to AVH. However, a significant association between CC area and overall grey and white matter volumes was noted in the hallucinating patients and, to a lesser extent, in the non-hallucinators, which may point to differing influences on brain development or degeneration in such patients compared with normal controls.

Gastrointestinal stromal tumor with a novel mutation of KIT proto-oncogene

The majority of human gastrointestinal mesenchymal tumors are gastrointestinal stromal tumors (GISTs). Recent reports have shown the existence of gain-of-function mutations in the juxta-membrane domain of receptor tyrosine kinase (KIT) in GISTs. We present a 77-year-old woman with GIST diagnosed by positive immunostaining of cluster designation (CD) 34 and KIT. This case had a novel mutation at codon 576 located in the juxta-membrane domain of KIT. Our results indicate the importance of mutations in this KIT region and suggest the possibility of the existence of other types of mutations in this region in GISTs.

Co-infection by serologically-silent hepatitis B virus may contribute to poor interferon response in patients with chronic hepatitis C by down-regulation of type-I interferon receptor gene expression in the liver

Intrahepatic mRNA levels of type-I interferon (IFN) receptor genes have been shown to correlate with the clinical efficacy of IFN therapy in patients with chronic hepatitis C. Recently, co-infection by serologically-silent hepatitis B virus (HBV) has been assumed to be associated with the poor IFN response in patients with chronic hepatitis C. The aim of this study was to investigate the relationship between the co-infection of serologically-silent HBV and type-I IFN receptor gene expression in the liver of patients with chronic hepatitis C. The intrahepatic mRNA levels of IFNAR2, one of the two subunits of the type-I IFN receptor, were quantified and compared with both the prevalence of HBV DNA and the hepatitis C virus (HCV) genotype in 45 patients with chronic hepatitis C, who were negative for hepatitis B surface antigen. Co-infection, as evaluated by a nested polymerase chain reaction, was present in 22 patients (48.9%), with dominance of the HCV genotype 1b (65.2%) over genotype 2a (31.8%). Co-infection was associated with lower IFNAR2 mRNA levels, higher levels of serum HCV RNA, and a poor IFN response, regardless of the HCV genotype. The findings suggest the possibility that co-infection by serologically-silent HBV is one of the factors that can lead to an unfavorable IFN response in chronic hepatitis C by down-regulation of IFN receptor gene expression in the liver.

Co-infection by serologically-silent hepatitis B virus may contribute to poor interferon response in patients with chronic hepatitis C by down-regulation of type-I interferon receptor gene expression in the liver

Intrahepatic mRNA levels of type-I interferon (IFN) receptor genes have been shown to correlate with the clinical efficacy of IFN therapy in patients with chronic hepatitis C. Recently, co-infection by serologically-silent hepatitis B virus (HBV) has been assumed to be associated with the poor IFN response in patients with chronic hepatitis C. The aim of this study was to investigate the relationship between the co-infection of serologically-silent HBV and type-I IFN receptor gene expression in the liver of patients with chronic hepatitis C. The intrahepatic mRNA levels of IFNAR2, one of the two subunits of the type-I IFN receptor, were quantified and compared with both the prevalence of HBV DNA and the hepatitis C virus (HCV) genotype in 45 patients with chronic hepatitis C, who were negative for hepatitis B surface antigen. Co-infection, as evaluated by a nested polymerase chain reaction, was present in 22 patients (48.9%), with dominance of the HCV genotype 1b (65.2%) over genotype 2a (31.8%). Co-infection was associated with lower IFNAR2 mRNA levels, higher levels of serum HCV RNA, and a poor IFN response, regardless of the HCV genotype. The findings suggest the possibility that co-infection by serologically-silent HBV is one of the factors that can lead to an unfavorable IFN response in chronic hepatitis C by down-regulation of IFN receptor gene expression in the liver.

Analysis of gastrin receptor gene expression in proliferating cells in the neck zone of gastric fundic glands using laser capture microdissection

Gastrin stimulates proliferation of progenitor cells in the neck zone of gastric fundic mucosa. However, whether it directly enhances this proliferation through its receptors remains unclear. We investigated the expression of gastrin receptors in neck zone proliferating cells in rat gastric fundic glands using a reverse transcription polymerase chain reaction (RT-PCR) coupled with laser capture microdissection and in situ RT-PCR. Gastrin receptor expression was identified in c-fos-expressing cells located in the neck zone, and results of the RT-PCR analysis argued against contamination by other cells, such as enterochromaffin-like, parietal or D cells. Supporting this finding, gastrin receptor gene expression was identified in the neck zone as well as base glands by in situ RT-PCR. Therefore, it is suggested that proliferating cells in the neck zone are stimulated directly by gastrin via their gastrin receptors.

Structural abnormalities in frontal, temporal, and limbic regions and interconnecting white matter tracts in schizophrenic patients with prominent negative symptoms

OBJECTIVE

Imaging studies of schizophrenia have repeatedly demonstrated global abnormalities of cerebral and ventricular volumes. However, pathological changes at more local levels of brain organization have not yet been so clearly characterized because of the few brain regions of interest heretofore included in morphometric analyses as well as heterogeneity of patient samples.

METHOD

Dual echo magnetic resonance imaging (MRI) data were acquired at 1.5 T from 27 right-handed patients who met DSM-IV criteria for schizophrenia with enduring negative symptoms and from 27 healthy comparison subjects. Between-group differences in gray and white matter volume were estimated at each intracerebral voxel after registration of the images in standard space. The relationship between clinical symptom scores and brain structure was also examined within the patient group. Spatial statistics and permutation tests were used for inference.

RESULTS

Significant deficits of gray matter volume in the patient group were found at three main locations: 1) the left superior temporal gyrus and insular cortex, 2) the left medial temporal lobe (including the parahippocampal gyrus and hippocampus), and 3) the anterior cingulate and medial frontal gyri. The volume of these three regions combined was 14% lower in the patients relative to the comparison subjects. White matter deficits were found in similar locations in the left temporal lobe and extended into the left frontal lobe. The patient group showed a relative excess of gray matter volume in the basal ganglia. Within the patient group, basal ganglia gray matter volume was positively correlated with positive symptom scores.

CONCLUSIONS

Anatomical abnormalities in these schizophrenic patients with marked negative symptoms were most evident in left hemispheric neocortical and limbic regions and related white matter tracts. These data are compatible with models that depict schizophrenia as a supraregional disorder of multiple, distributed brain regions and the axonal connections between them.