High-Fat Diet-Induced Diabetic Conditions Exacerbate Cognitive Impairment in a Mouse Model of Alzheimer's Disease Via a Specific Tau Phosphorylation Pattern

BACKGROUND

Epidemiological evidence has demonstrated a clear association between diabetes mellitus and increased risk of Alzheimer's disease (AD). Cerebral accumulation of phosphorylated tau aggregates, a cardinal neuropathological feature of AD, is associated with neurodegeneration and cognitive decline. Clinical and experimental studies indicate that diabetes mellitus affects the development of tau pathology; however, the underlying molecular mechanisms remain unknown.

OBJECTIVE

In the present study, we used a unique diabetic AD mouse model to investigate the changes in tau phosphorylation patterns occurring in the diabetic brain.

DESIGN

Tau-transgenic mice were fed a high-fat diet (n = 24) to model diabetes mellitus. These mice developed prominent obesity, severe insulin resistance, and mild hyperglycemia, which led to early-onset neurodegeneration and behavioral impairment associated with the accumulation of hyperphosphorylated tau aggregates.

RESULTS

Comprehensive phosphoproteomic analysis revealed a unique tau phosphorylation signature in the brains of mice with diabetic AD. Bioinformatic analysis of the phosphoproteomics data revealed putative tau-related kinases and cell signaling pathways involved in the interaction between diabetes mellitus and AD.

CONCLUSION

These findings offer potential novel targets that can be used to develop tau-based therapies and biomarkers for use in AD.

C-type lectin Mincle-dependent and -independent activation of invariant NKT cells by exposure to Helicobacter pylori α-cholesteryl glucosides

Helicobacter pylori extracts cholesterol from the host and converts it to its glycosides. We found that cholesteryl 6'-O-acyl α-glucoside (ChAcαG) produced by H. pylori is recognised by both invariant Vα14⁺ NKT (iNKT) cells and a C-type lectin receptor Mincle (Clec4e). However, it is unclear how these duplicated recognitions cooperate and contribute to host defence against H. pylori. Among T cell populations in the liver, iNKT cells predominantly expressed the T cell activation marker CD69 just after stimulation with ChAcαG. The production of IFN-γ and IL-4 was strictly dependent on both CD1d and Jα18 expressions, indicating the necessity of iNKT cell activation for the initiation of immune responses. Production of IFN-γ by iNKT cells was markedly reduced by the Mincle deficiency on antigen-presenting cells (APCs), while IL-4 production was not significantly influenced. IL-2 production by iNKT cell hybridomas was also diminished by the Mincle deficiency upon stimulation with APCs previously loaded with ChAcαG. Here, the immune responses of iNKT cell hybridomas stimulated with wild-type APCs were reduced by the addition of anti-IL-12 blocking antibody to the level stimulated with Mincle-deficient APCs. Collectively, these results suggest that iNKT cells can be activated with the cholesteryl glycosides via a Mincle-dependent, IL-12 signal-dependent pathway and a Mincle-independent, invariant TCR signal-dominant pathway. iNKT cells activated via the Mincle-dependent pathway produce IFN-γ-dominant cytokines; hence, they may contribute to enhancing proinflammatory responses against H. pylori infection.

Studies on expression of aldehyde dehydrogenase in normal and cancerous tissues of thyroids

Recently published articles have reported the controversial data regarding expression of aldehyde dehydrogenase isozyme 1A1 (ALDH1A1), a potential candidate marker for normal and cancer stem cells (CSCs), in thyroid tissues. These data prompted us to re-evaluate expression of ALDH1A1 in normal and cancerous thyroid tissues by 2 different means. The first method was immunohistochemistry with 2 different anti-ALDH1A1 antibodies from distinct companies. Following validating the integrity of these 2 antibodies by Western blotting with ALDH-expressing and nonexpressing cancer cell lines and immunohistochemistry with breast and colon tissues, we report here significant and comparable expression of ALDH1A1 in both normal and cancerous thyroid tissues with both antibodies. Next, relative expression levels of ALDH isozymes were evaluated by reverse transcription-polymerase chain reaction (RT-PCR), revealing that ALDH1A1 was the most highly expressed isozyme followed by ALDH9A1 and relative expression patterns of isozymes were very similar in normal and cancerous tissues. All these data demonstrate that thyroid cells of normal and cancer origins do express ALDH1A1 and to a lesser extent 9A1. Further study will be necessary to study functional significance of ALDH1A1 in the function and behaviors of thyroid normal and cancer stem cells.

Therapeutic potential of cholesteryl O-acyl α-glucoside found in Helicobacter pylori

Steryl glycosides are derivatives of sterols where the 3β-hydroxy group is glycosylated. Some of them are further converted to steryl O-acyl glycosides. Steryl glycosides and their derivatives are widely distributed in plants, algae, and fungi, but are relatively rarely distributed in bacteria and animals. Accumulating evidence suggests that glycosylation of sterols not only modifies physicochemical properties of cell membranes but also alters immunogenicity of the cells. Helicobacter pylori, that colonizes the stomach and causes gastric diseases, is auxotrophic for cholesterol, so that it extracts this lipid from plasma membranes of epithelial cells of the host stomach. Since incorporation of cholesterol promotes immune responses of the host, Helicobacter pylori converts cholesterol to cholesteryl glucoside (ChG) and then to cholesteryl 6'-O-acyl glucoside (ChAcG) to evade the immune surveillance. We have found that ChAcG thus produced is specifically recognized by invariant Vα14-Jα18 TCR(+) (Vα14) NKT cells in a CD1-dependent manner. We have also found that activation of Vα14 NKT cells by administration of ChAcG retains homeostasis of immunity upon exposure to allergens and reduces the incidence of allergy. In this article, overview of immunological functions of steryl glycosides with an emphasis on the immunoregulatory functions of ChAcG, is demonstrated.

Prophylactic and therapeutic efficacies of a selective inhibitor of the immunoproteasome for Hashimoto's thyroiditis, but not for Graves' hyperthyroidism, in mice

Major histocompatibility complex (MHC) class I-restricted T cell epitopes are generated mainly by the immunoproteasome in antigen-presenting cells. Therefore, inhibition of activity of this proteolytic complex molecule is thought to be a potential treatment for cell-mediated autoimmune diseases. We therefore studied the efficacy of an immunoproteasome inhibitor, ONX 0914 (formerly PR-957), for the treatment of autoimmune thyroid diseases, including cell-mediated Hashimoto's thyroiditis and autoantibody-mediated Graves' hyperthyroidism using mouse models. Our data show that ONX 0914 was effective prophylactically and therapeutically at suppressing the degree of intrathyroidal lymphocyte infiltration and, to a lesser degree, the titres of anti-thyroglobulin autoantibodies in non-obese diabetic (NOD)-H2(h4) mice, an iodine-induced autoimmune thyroiditis model. It also inhibited differentiation of T cells to T helper type 1 (Th1) and Th17 cells, effector T cell subsets critical for development of thyroiditis in this mouse strain. In contrast, its effect on the Graves' model was negligible. Although ONX 0914 exerts its immune-suppressive effect through not only suppression of immune proteasome but also other mechanism(s), such as inhibition of T cell differentiation, the present results suggest that the immunoproteasome is a novel drug target in treatment of Hashimoto's thyroiditis in particular and cell-mediated autoimmune diseases in general.

Modulation of immunoglobulin production by invariant Vα19-Jα33 TCR-bearing cells

We have previously shown that invariant Vα19-Jα33 TCR(+) (Vα19i T) cells suppress the disease progress in some models for organ specific autoimmune diseases and type IV allergy that deteriorate along with decline to excess in Th1- or Th17- immunity. In this study, we examined the effects of over-generation of Vα19i T cells on the Th2-controlled immunoglobulin isotype production in the models for type I allergy. IgE production by invariant Vα19-Jα33 TCR transgenic (Tg) mice was suppressed compared with that by non-Tg controls following administration with goat anti-mouse IgD antiserum or OVA, while IgG2a production was not influenced by the introduction of the transgene into the recipients. IgE production by wild type mice was similarly reduced when they were subjected to adoptive transfer with invariant Vα19-Jα33 TCR Tg(+) but not Tg(-) cells prior to immunization. Furthermore, the suppression of IgE production by these recipients was enhanced when they were previously administered with a Vα19i T cell activator, one of the modified α-mannosyl ceramides. In summary, it is suggested that Vα19i T cells have potential to participate in the homeostasis of immunity and that they suppress disease progression resulting from not only Th1- but also Th2- immunity excess.

Influenza infection in suckling mice expands an NKT cell subset that protects against airway hyperreactivity

Infection with influenza A virus represents a major public health threat worldwide, particularly in patients with asthma. However, immunity induced by influenza A virus may have beneficial effects, particularly in young children, that might protect against the later development of asthma, as suggested by the hygiene hypothesis. Herein, we show that infection of suckling mice with influenza A virus protected the mice as adults against allergen-induced airway hyperreactivity (AHR), a cardinal feature of asthma. The protective effect was associated with the preferential expansion of CD4-CD8-, but not CD4+, NKT cells and required T-bet and TLR7. Adoptive transfer of this cell population into allergen-sensitized adult mice suppressed the development of allergen-induced AHR, an effect associated with expansion of the allergen-specific forkhead box p3+ (Foxp3+) Treg cell population. Influenza-induced protection was mimicked by treating suckling mice with a glycolipid derived from Helicobacter pylori (a bacterium associated with protection against asthma) that activated NKT cells in a CD1d-restricted fashion. These findings suggest what we believe to be a novel pathway that can regulate AHR, and a new therapeutic strategy (treatment with glycolipid activators of this NKT cell population) for asthma.

Altered production of immunoregulatory cytokines by invariant Valpha19 TCR-bearing cells dependent on the duration and intensity of TCR engagement

Cells bearing invariant Valpha19-Jalpha33 TCR alpha chains are believed to participate in the regulation of inflammatory autoimmune diseases. In this study, the potential to produce immunoregulatory cytokines by these cells was characterized in order to find the mechanism underlying their immunoregulatory functions. Serum levels of IL-4, IL-10, transforming growth factor-beta, IFN-gamma and IL-17 increased in mice over-expressing an invariant Valpha19-Jalpha33 TCR alpha transgene (Valpha19 Tg) in response to anti-CD3 antibody injection. NK1.1(+) Valpha19 Tg(+), but not NK1.1(-) Valpha19 Tg(+) cells, promptly produced immunoregulatory IL-4, IFN-gamma and IL-17 upon invariant TCR engagement with immobilized anti-CD3 antibody in culture. The activation of Valpha19 Tg(+) cells then triggered the production of pro-inflammatory cytokines by bystander cells. Interestingly, the ratio of T(h)2 cytokines such as IL-4, IL-5 and IL-10, but not pro-inflammatory IL-17, to IFN-gamma was increased when the intensity of the stimulation to invariant TCR was attenuated. Collectively, these findings suggest that invariant Valpha19 TCR(+) cells have the potential to participate in the regulation of inflammatory autoimmunity by producing T(h)2-biased cytokines in certain circumstances.

Localization of NK1.1(+) invariant Valpha19 TCR(+) cells in the liver with potential to promptly respond to TCR stimulation

Previously, we found that more than a half of the NK1.1(+) T cell lines prepared from CD1(-/-) livers expressed invariant Valpha19-Jalpha33 TCR alpha chains. Over-expression of the invariant Valpha19-Jalpha33 TCR alpha transgene (Tg) with a natural TCR alpha promoter and an enhancer in mice induced the development of NK1.1(+) T cells (Valpha19 NKT cells) in the lymphoid organs, especially in the liver. Preferential usage of the Valpha19 Tg by NKT cells in the transgenic mouse livers was indirectly indicated by the observation that few NK1.1(+) TCRalphabeta(+) cells of the Valpha19 Tg livers were stained with a cocktail of anti-TCR Valpha antibodies in the FACS analysis. Upon invariant TCR engagement in vivo following injection of mice with anti-CD3 antibody, NKT cells of the Tg mouse livers as well as spleens promptly produced immunoregulatory cytokines such as IL-4 and IFN-gamma and altered surface receptor expression. Collectively, localization of Valpha19 NKT cells in the liver is suggested that are ready to immediately response against antigen stimulation.

Glycolipid stimulators for NKT cells bearing invariant V alpha 19-J alpha 33 TCR alpha chains

Attempts have been made to find specific antigens for a novel NKT cell subset bearing invariant V alpha 19-J alpha 33 TCR alpha chains (V alpha 19 NKT cell). Comprehensive examinations revealed substantial antigenic activity in synthetic alpha-mannosylceramide (ManCer) that was presented by MR1. Structural modification of the sphingosine moiety of alpha-ManCer improved antigenic activity to enhance either Th1 or Th2 -promoting cytokine production by V alpha 19 NKT cells. Such alpha-ManCer analogues will be useful for developing new therapies as immunomodulators.

Non-reducing end alpha-mannosylated glycolipids as potent activators for invariant Valpha19 TCR-bearing natural killer T cells

A novel invariant Valpha19-Jalpha33 T cell receptor alpha chain, first found in mammalian blood cells, was primarily expressed by natural killer T cell repertoire (Valpha19 NKT cell). Attempts have been made to find specific antigens for Valpha19 NKT cells. A series of alpha- and beta-glycosyl ceramides were synthesized and tested whether they had potential to stimulate the cells isolated from invariant Valpha19-Jalpha33 TCR transgenic mice (where the development of Valpha19 NKT cells is facilitated). Comprehensive examinations revealed substantial antigenic activity in alpha-ManCer that was presented by MR1, one of the MHC class Ib molecules. Next, naturally occurring and synthetic alpha-mannosyl glycolipids were further analyzed to determine structural requirements for natural ligands for Valpha19 NKT cells. As a result, alpha-mannosyl phosphatidyl inositols (PI) such as (alpha-Man)(2)-PI and alpha-Man-alpha-GlcNH(2)-PI (a partial structure of mycobacterial lipoarabinomannan and GPI-anchors) as well as alpha-ManCer derivatives were found to activate Valpha19 NKT cells in vivo and in vitro. Thus, Valpha19 NKT cells are possibly responsive to certain alpha-mannosyl glycolipids and may have roles in the innate and adaptative immune systems to protect against various antigens expressing alpha-mannosyl glycolipids and to regulate the adaptive immune system responding to the intracellular ligands.

Role of interleukin-1beta and tumor necrosis factor-alpha-dependent expression of cyclooxygenase-2 mRNA in thermal hyperalgesia induced by chronic inflammation in mice

The present study investigated whether the endogenous pro-inflammatory cytokines [interleukin (IL)-1beta and tumor necrosis factor-alpha (TNF-alpha)]-dependent expression of cyclooxygenase-2 (COX-2) mRNA within the spinal cord could be involved in the development of chronic inflammatory pain-like behaviors in mice. We demonstrated that the expression of COX-2 mRNA on the ipsilateral side of the spinal cord was significantly increased 6 h and 3 days after intraplantar injection of complete Freund's adjuvant (CFA), compared with the expression in saline-treated mice. In addition, the chronic pain-like behaviors following CFA injection were markedly suppressed by repeated intrathecal (i.t.) pre-treatment with the COX-2 inhibitor etodolac, but not with the COX-1 inhibitor mofezolac. The cytosolic level of the activated form of nuclear factor-kappa B (NF-kappaB), which is a major contributor to the induction of COX-2, on the ipsilateral side of the mouse spinal cord was also increased compared with that in the saline-treated mice. The key finding in the present study was that a single i.t. injection with either IL-1beta or TNF-alpha induced a marked increase in spinal COX-2 mRNA and persistent thermal hyperalgesia in mice. Furthermore, CFA-induced hypersensitivity to inflammatory pain was significantly reduced by repeated i.t. pre-injection of the recombinant Fc chimera of IL-1 receptor I or soluble TNF receptor I, which sequesters endogenous IL-1beta or TNF-alpha, respectively. In contrast, the expression of spinal COX-2 mRNA in CFA-treated mice was similar to that in saline-treated mice at 7 days after CFA injection. The present findings strongly indicate the early intrathecal use of the COX-2 inhibitor for the relief of chronic inflammatory pain. Furthermore, together with the result in a previous study that pro-inflammatory cytokines lead to stimulation of a NF-kappaB-dependent transcriptional pathway, these findings suggest that a spinal cytokine/NF-kappaB/COX-2 pathway may play an important role in the development, but not maintenance, of chronic pain following peripheral tissue inflammation.

Modulation of Valpha19 NKT cell immune responses by alpha-mannosyl ceramide derivatives consisting of a series of modified sphingosines

We have demonstrated that analogues of alpha-mannosyl ceramide (alpha-ManCer) consisting of a series of immunosuppressive 2-aminoalcohol derivatives in place of sphingosine promote a greater immune response from mouse invariant Valpha19-Jalpha26 (AV19-AJ33) TCR-bearing NKT (Valpha19 NKT) cells than alpha-ManCer itself. To further characterize the immune responses of Valpha19 NKT cells to the alpha-ManCer analogues, cytokine production by the cells was examined in detail. We found that certain alpha-ManCer derivatives individually induced either Th1- or Th2-dominant cytokine production in culture. The Th1- or Th2-biased immune responses of Valpha19 NKT cells were dependent on MHC class I-like MR1, since they were induced by coculture with the MR1 transfectants previously loaded with the glycolipids and were inhibited in the presence of anti-MR1 antiserum. Presumably, the recognition of the alpha-mannosyl residue of the alpha-ManCer analogues by the invariant TCR is individually modulated, depending on the altered interaction with the groove of the antigen-presenting MR1. Priming of the Valpha19 invariant TCR-transgenic mice in vivo with these glycolipid derivatives resulted in the induction of the Th1- or Th2-biased immune responses. Thus, these alpha-ManCer derivatives are likely to be useful in immunotherapy for either Th1 or Th2 excess autoimmune diseases, modulating the function of Valpha19 NKT cells.

Glycolipids with nonreducing end alpha-mannosyl residues that have the potential to activate invariant Valpha19 NKT cells

We have previously demonstrated that alpha-mannosyl ceramide and its derivatives promote immune responses of NK1.1(+) invariant Valpha19-Jalpha33 T cell receptor (TCR) alpha(+) T cells (Valpha19 NKT cells). In this study, attempts were made to determine the structural requirements for natural ligands for Valpha19 NKT cells. Naturally occurring and synthetic glycolipids were analyzed for their ability to stimulate the cells prepared from invariant Valpha19-Jalpha33 TCR transgenic mice, in which development of Valpha19 NKT cells is facilitated. As a result, alpha-mannosyl phosphatidylinositols such as 2,6-di-alpha-mannosyl phosphatidylinositol and alpha-mannosyl-4alpha-glucosaminyl-6-phosphatidylinositol (alpha-Man-GlcNH(2)-PtdIns) as well as alpha-mannosyl ceramide derivatives were found to activate the cells from the transgenic mouse liver, gut lamina propria and spleen in vivo and in vitro. Thus, glycolipids with nonreducing end alpha-mannosyl residues are suggested to be potent antigens for Valpha19 NKT cells. Next, a series of invariant Valpha19-Jalpha33 TCR(+) hybridomas, each with variations in the sequence of the Valpha-Jalpha junction and the TCR beta chain, were tested for responsiveness toward the alpha-mannosyl glycolipids. A loose correlation between the primary structure of the TCR and the reactive glycolipids was observed. For instance, hybridomas expressing TCRs consisting of an alpha chain with a variation in the Valpha19-Jalpha33 junction and a Vbeta6(+)beta chain showed affinity towards alpha-mannosyl ceramide and alpha-Man-GlcNH(2)-PtdIns, whereas those expressing TCRs with an invariant Valpha19-Jalpha33 alpha chain and a Vbeta8(+)beta chain responded to 2,6-di-alpha-mannosyl phosphatidylinositol. Thus, it is suggested that Valpha19 NKT cells with microheterogeneity in the TCR structure have been generated for defense against various antigens expressing alpha-mannosyl glycolipids.

The validity of a hyperventilation test for an investigation of autonomic failure: assessment in patients with multiple system atrophy and Parkinson's disease

Although heart rate (HR) responses to hyperventilation (HV) have been used as a cardiovascular autonomic function test, autonomic involvement during HV remains uncertain. To clarify the relationship between autonomic activity and cardiovascular changes during HV, we compared cardiovascular responses during HV among subjects with different autonomic function, namely 16 patients with probable multiple system atrophy (MSA), 16 with possible MSA, 28 with Parkinson's disease (PD) and 28 healthy controls. Abnormalities of cardiovascular responses to head-up postural change and the Valsalva maneuver were definitely present in the order of probable MSA, possible MSA and PD, and abnormal HR and blood pressure (BP) responses during HV were observed in probable MSA and possible MSA, but not in PD. Unlike the significant difference in standard cardiovascular autonomic function tests, the HR and BP responses during HV were equivalent between probable and possible MSA. These findings suggest that cardiovascular control during HV may be affected not only by autonomic activity but also by other factors.

Coexpression of an unusual form of the EWS-WT1 fusion transcript and interleukin 2/15 receptor betamRNA in a desmoplastic small round cell tumour

BACKGROUND

The beta chain of the interleukin 2/15 receptor (IL-2/15Rbeta) is induced by the expression of the EWS-WT1. A case of desmoplastic small round cell tumour (DSRCT) expressing only an unusual EWS-WT1 treated by us is reported here.

AIM

To characterise an unusual form of EWS-WT1.

METHODS

Frozen tissue sections of the axillary tumour were examined using a laser-assisted microdissection technique and reverse transcriptase polymerase chain reaction.

RESULTS

The novel fusion of exon 8 of EWS and the defective exon 10 of WT1 (-KTS) was detected. Although it was an unusual form, the coexpression of the present EWS-WT1, IL-2/15Rbeta and Janus kinase (JAK1) mRNA was detected in the tumour cells. IL-2 and signal transducers and activators of transcription (STAT5) mRNA were detected in both tumour and stromal cells.

CONCLUSION

The induction of the IL-2/15 receptor signalling pathway may contribute to tumorigenesis in DSRCT through a paracrine or an autocrine system, even though the EWS-WT1 was an unusual form.

Invariant V(alpha)19i T cells regulate autoimmune inflammation

T cells expressing an invariant V(alpha)19-J(alpha)33 T cell receptor alpha-chain (V(alpha)19i TCR) are restricted by the nonpolymorphic major histocompatibility complex class Ib molecule MR1. Whether V(alpha)19i T cells are involved in autoimmunity is not understood. Here we demonstrate that T cells expressing the V(alpha)19i TCR transgene inhibited the induction and progression of experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis. Similarly, EAE was exacerbated in MR1-deficient mice, which lack V(alpha)19i T cells. EAE suppression was accompanied by reduced production of inflammatory mediators and increased secretion of interleukin 10. Interleukin 10 production occurred at least in part through interactions between B cells and V(alpha)19i T cells mediated by the ICOS costimulatory molecule. These results suggest an immunoregulatory function for V(alpha)19i T cells.

Prevention of onset of Parkinson's disease by in vivo gene transfer of human hepatocyte growth factor in rodent model: a model of gene therapy for Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra (SNi). As neurotrophic factors support the survival and enhance the function of dopaminergic neurons, gene therapy using neurotrophic factors has become the center of interest. Thus, we focused on hepatocyte growth factor (HGF) as a neurotrophic and angiogenic growth factor. At 7 days before injection of 6-hydroxydopamine into the SNi, stereotaxic transfection of human HGF or lacZ plasmid was performed into the unilateral striatum of rats. Expression of human HGF in the injected sites could be detected in rats transfected with HGF plasmid DNA, using immunohistochemical staining. Consistently, human immunoreactive HGF protein could be detected at least up to 12 days after transfection. Interestingly, PD rats transfected with lacZ demonstrated amphetamine-induced rotational asymmetry. However, transfection of HGF plasmid DNA resulted in significant inhibition of abnormal rotation up to 24 weeks in a dose-dependent manner. Over 90% of dopaminergic neurons were lost in PD rats transfected with lacZ, whereas over 70% survived in rats transfected with HGF, as assessed by immunohistochemical staining. Overall, the present study demonstrated that overexpression of HGF prevented neuronal death in a PD rat model, providing a potential novel therapy for PD.

Induction of promotive rather than suppressive immune responses from a novel NKT cell repertoire Vα19 NKT cell with α-mannosyl ceramide analogues consisting of the immunosuppressant ISP-I as the sphingosine unit

A 2-substituted 2-aminopropane-1,3-diol or 2-aminoethanol is the minimum structure required for the immunosuppressive activity of ISP-I, an antibiotic isolated from the culture broth of Isaria sinclairil. A series of alpha-mannosyl ceramide (alpha-ManCer) analogues was derived from 2-substituted 2-aminopropane-1,3-diols or 2-aminoethanols in place of sphingosine. The newly synthesized glycosides were evaluated for their effects on immune responses. In contrast to the immunosuppressive activity of the precursors, the alpha-ManCer analogues induced immunopromotive responses from invariant Valpha19-Jalpha26 transgenic mouse lymphocytes more effectively than the original alpha-ManCer. Collectively, it is strongly suggested that the 2-substituted 2-aminopropane-1,3-diols and 2-aminoethanols mimic sphingosine in the alpha-ManCer analogues so that they potentially acquire specific antigenicity toward Valpha19 NKT cell, a novel NKT cell subset.

L-3,4-dihydroxyphenylalanine-induced c-Fos expression in the CNS under inhibition of central aromatic L-amino acid decarboxylase

L-3,4-dihydroxyphenylalanine (DOPA) is a neurotransmitter candidate. To map the DOPAergic system functionally, DOPA-induced c-Fos expression was detected under inhibition of central aromatic L-amino acid decarboxylase (AADC). In rats treated with a central AADC inhibitor, DOPA significantly increased the number of c-Fos-positive nuclei in the paraventricular nuclei (PVN) and the nucleus tractus solitarii (NTS), and showed a tendency to increase in the supraoptic nuclei (SON), but not in the striatum. On the other hand, DOPA with a peripheral AADC inhibitor elevated the level of c-Fos-positive nuclei in the four regions, suggesting that DOPA itself induces c-Fos expression in the SON, PVN and NTS. In rats treated with 6-hydroxydopamine (6-OHDA) to lesion the nigrostriatal dopamine (DA) pathway, DOPA significantly induced c-Fos expression in the four regions under the inhibition of peripheral AADC. However, under the inhibition of central AADC, DOPA did not significantly increase the number of c-Fos-positive nuclei in the four regions, suggesting that DOPA at least in part induces c-Fos expression through its conversion to DA. It was likely that the 6-OHDA lesion enhanced the response to DA, but attenuated that to DOPA itself. In conclusion, we proposed that the SON, PVN and NTS include target sites for DOPA itself.

Synthetic alpha-mannosyl ceramide as a potent stimulant for an NKT cell repertoire bearing the invariant Valpha19-Jalpha26 TCR alpha chain

A NKT cell repertoire is characterized by the expression of the Valpha19-Jalpha26 invariant TCR alpha chain (Valpha19 NKT cell). This repertoire, as well as a well-established Valpha14-Jalpha281 invariant TCR alpha(+) NKT cell subset (Valpha14 NKT cell), has been suggested to have important roles in the regulation of the immune system and, thus, is a major therapeutic target. Here, we attempted to find specific antigens for Valpha19 NKT cells. Valpha19 as well as Valpha14 NKT cells exhibited reactivity to alpha-galactosyl ceramide (alpha-GalCer). Thus, a series of monoglycosyl ceramides with an axially oriented glycosidic linkage between the sugar and ceramide moiety were synthesized and their antigenicity to Valpha19 NKT cells was determined by measuring their immune responses in culture with glycolipids. Comprehensive examinations revealed substantial antigenic activity for Valpha19 NKT cells by alpha-mannosyl ceramide.

Suppression of PI3K/mTOR pathway rescues LLC cells from cell death induced by hypoxia

Cancer cells in solid tumors are challenged by various microenvironmental stresses, including hypoxia, and cancer cells in hypoxic regions are resistant to current cancer therapies. To investigate the mechanism of resistance to hypoxia in cancer cells, we examined mouse Lewis lung carcinoma (LLC) cells, which died due to necrosis at high density under hypoxic but not under normoxic conditions. Levels of mammalian target of rapamycin (mTOR), a central regulator of cellular energy, are reported to be suppressed in hypoxia. We found that phosphorylation of two molecules downstream to it, ribosomal p70 S6 kinase (S6K) and ribosomal protein S6, was markedly suppressed by hypoxia. Overexpression of the active form of S6K increased the sensitivity of LLC cells to hypoxia. On the other hand, inhibition of PI3K or mTOR dramatically reduced hypoxia-induced cell death under hypoxic conditions. Under hypoxic conditions, blockade of the PI3K or mTOR pathway increased levels of intracellular ATP and delayed decreases in pH and glucose level in culture medium, without affecting the cell cycle.

Analysis of long-term gene expression in neurons of the hippocampal subfields following traumatic brain injury in rats

After experimental traumatic brain injury (TBI), widespread neuronal loss is progressive and continues in selectively vulnerable brain regions, such as the hippocampus, for months to years after the initial insult. To clarify the molecular mechanisms underlying secondary or delayed cell death in hippocampal neurons after TBI, we compared long-term changes in gene expression in the CA1, CA3 and dentate gyrus (DG) subfields of the rat hippocampus at 24 h and 3, 6, and 12 months after TBI with changes in gene expression in sham-operated rats. We used laser capture microdissection to collect several hundred hippocampal neurons from the CA1, CA3, and DG subfields and linearly amplified the nanogram samples of neuronal RNA with T7 RNA polymerase. Subsequent quantitative analysis of gene expression using ribonuclease protection assay revealed that mRNA expression of the anti-apoptotic gene, Bcl-2, and the chaperone heat shock protein 70 was significantly downregulated at 3, 6 (Bcl-2 only), and 12 months after TBI. Interestingly, the expression of the pro-apoptotic genes caspase-3 and caspase-9 was also significantly decreased at 3, 6 (caspase-9 only), and 12 months after TBI, suggesting that long-term neuronal loss after TBI is not mediated by increased expression of pro-apoptotic genes. The expression of two aging-related genes, p21 and integrin beta3 (ITbeta3), transiently increased 24 h after TBI, returned to baseline levels at 3 months and significantly decreased below sham levels at 12 months (ITbeta3 only). Expression of the gene for the antioxidant glutathione peroxidase-1 also significantly increased 6 months after TBI. These results suggest that decreased levels of neuroprotective genes may contribute to long-term neurodegeneration in animals and human patients after TBI. Conversely, long-term increases in antioxidant gene expression after TBI may be an endogenous neuroprotective response that compensates for the decrease in expression of other neuroprotective genes.

Development of efficient plasmid DNA transfer into adult rat central nervous system using microbubble-enhanced ultrasound

Although gene therapy might become a promising approach for central nervous system diseases, the safety issue is a serious consideration in human gene therapy. To overcome this problem, we developed an efficient gene transfer method into the adult rat brain based on plasmid DNA using a microbubble-enhanced ultrasound method, since microbubble-enhanced ultrasound has shown promise for transfecting genes into other tissues such as blood vessels. Using the microbubble-enhanced ultrasound method, luciferase expression was increased approximately 10-fold as compared to injection of naked plasmid DNA alone. Interestingly, the site of gene expression was limited to the site of insonation with intracisternal injection, in contrast to previous studies using viruses. Expression of the reporter gene, Venus, was readily detected in the central nervous system. The transfected cells were mainly detected in meningeal cells with intracisternal injection, and in glial cells with intrastriatal injection. There was no obvious evidence of tissue damage by microbubble-enhanced ultrasound. Overall, the present study demonstrated the feasibility of efficient plasmid DNA transfer into the central nervous system, providing a new option for treating various diseases such as tumors.

Accumulation of Valpha7.2-Jalpha33 invariant T cells in human autoimmune inflammatory lesions in the nervous system

T cells expressing an invariant TCR alpha chain and NK cell markers are expected to exhibit unique functions. Whereas much attention has been paid to CD1d-restricted NKT cells, a second NKT cell population bearing an invariant AV19-AJ33 TCR has recently been identified in mice and humans. Selection and/or expansion of this population require B cells, and would involve a non-classical class I-related molecule MR1. Although their preferential distribution in the gut mucosa indicates their role in the host response at the site of pathogen entry, it remains unknown whether they play an alternative role at different sites or in immunological disorders. Using single-strand conformation polymorphism clonotype analysis, we investigated the presence of the human AV19-AJ33 T cells (V(alpha)7.2-J(alpha)33 T cells) in autopsy samples from multiple sclerosis (MS) patients as well as in nerve biopsy samples from chronic inflammatory demyelinating polyneuropathy (CIDP) patients. Here we report that the V(alpha)7.2-J(alpha)33 T cells are accumulated in some of the central nervous system lesions of MS and in the majority of the peripheral nerve samples from CIDP. We have previously revealed that CD1d-restricted, V(alpha)24-J(alpha)Q NKT cells are remarkably reduced in the peripheral blood from MS. However, V(alpha)7.2-J(alpha)33 T cells are not reduced in the peripheral blood from MS and could be detected in a large majority of the cerebrospinal fluid samples obtained during relapse of MS. The present results indicate that the V(alpha)7.2-J(alpha)33 T cells are involved in the autoimmune inflammatory lesions.

Generation of Valpha14 NKT cells in vitro from hematopoietic precursors residing in bone marrow and peripheral blood

We previously reported the generation of Valpha14 invariant TCR+ (Valpha14i) NK1.1+ natural killer T (NKT) cells in the cytokine-activated suspension culture of murine fetal liver cells. In this study, we attempted to apply this finding to the induction of Valpha14i NKT cell differentiation in the culture of hematopoietic precursors residing in bone marrow or peripheral blood. Preferential generation of NKT cells was found in the culture of Thy-1(+)-depleted bone marrow cells in the presence of culture supernatant from Con A-stimulated spleen T cells and a combination of recombinant IL-3, IL-4, IL-7 and GM-CSF. NKT cell development from peripheral blood hematopoietic precursors was induced when they were cultured on stromal cell monolayers prepared from Thy-1(+)-depleted bone marrow or fetal liver cells, suggesting that certain environments derived from hematopoietic organs are required for the induction of NKT cells from precursors in vitro. A significant fraction of NKT cells generated in the culture were positive for staining with CD1-alpha-galactosylceramide tetramer, indicating that Valpha14i NKT cells were the major subset among the NKT cells. The present methods for obtaining NKT cells in the culture of bone marrow or peripheral blood cells are applicable to the treatment of patients suffering from diseases with numerical and functional disorders of NKT cells.

[Complications of video-assisted thoracoscopic surgery]

We introduced video-assisted thoracoscopic surgery (VATS) for chest disorders in our institution in March, 1992. At first, many of the subjects' disorders were non-malignant diseases such as spontaneous pneumothorax, but later we started to perform this procedure for lung cancer and mediastinum neoplasm, with improved result over thoracoscopic surgical procedures. Now most of the chest disorders at our institution are treated with VATS. However, many kinds of complications due to manual techniques and instrument troubles surfaced during this period. Therefore, in this article we would like to describe the complications that we have experienced in our institution using VATS and discuss how we have attempted to deal with these complications.

A novel hypoxia-dependent 2-nitroimidazole KIN-841 inhibits tumour-specific angiogenesis by blocking production of angiogenic factors

Tumour angiogenesis is initiated by angiogenic factors that are produced in large amounts by hypoxic tumour cells. The inhibition of this step may lead to tumour-specific antiangiogenesis because normal tissues are not usually hypoxic. On the other hand, blocking a biological function of endothelial cells is known to result in angiogenic inhibition. To produce a tumour-specific and powerful antiangiogenesis, we determined whether potent angiogenic inhibition could be achieved by inhibiting the production of angiogenic factors by hypoxic tumour cells and simultaneously blocking certain angiogenic steps in endothelial cells under normoxia. We focused on the 2-nitroimidazole moiety, which is easily incorporated into hypoxic cells and exhibits its cytotoxicity as hypoxic cytotoxin. We designed and synthesised 2-nitroimidazole derivatives designated as KIN compounds, and investigated their antiangiogenic activities under normoxia using a chick embryo chorioallantoic membrane. KIN-841 (2-nitroimidazole 1-acetylhydroxamate) showed a potent angiogenic inhibition in a dose-dependent manner. This compound inhibited the proliferation of bovine pulmonary arterial endothelial (BPAE) cells more strongly than that of tumour cells, such as Lewis lung carcinoma (3LL) cells, under normoxia. The inhibition of cell proliferation by KIN-841 under hypoxia increased about five-fold compared to that under normoxia. Moreover, under hypoxia, KIN-841 significantly decreased the excessive production of vascular endothelial cell growth factors induced by 3LL cells as determined by tritium-labelled thymidine ([(3)H]thymidine) incorporation into BPAE cells and by ELISA. Intraperitoneal administration of KIN-841 suppressed 3LL-cell-induced in vivo angiogenesis in the mouse dorsal air sac system. These results indicate that the regulation of the production of angiogenic factors by hypoxic tumour cells is a useful target for tumour-specific angiogenesis inhibition, and that KIN-841, which causes simultaneous direct inhibition of endothelial cell function and production of angiogenic factors by hypoxic tumour cells, is a very potent inhibitor of tumour-specific angiogenesis. Thus, the potential for clinical use of KIN-841 as an antitumour drug is very high.

Antibody production in early life supported by maternal lymphocyte factors

To examine the influence of maternal lymphocyte factors on the immune responses in offspring in early life, antibody production in neonates born to either normal or lymphocyte-deficient mothers was analyzed. Recombination activating gene (Rag)-2(+/-) mouse neonates born to Rag-2(+/+), Rag-2(+/-)or Rag-2(-/-)mothers were injected with goat anti-mouse IgD antiserum, and IgE and IgG(1) production was evaluated. The levels of IgE and IgG(1) were higher in the pups born to Rag-2(+/+)and Rag-2(+/-) dams than to lymphocyte-deficient Rag-2(-/-) dams. The enhanced antibody production in the former compared with the latter neonates was also found following immunization with ovalbumin or TNP-Ficoll. Thus, the presence of maternal lymphocyte factors was suggested in neonates that augmented antigen-specific antibody production in both T cell-dependent and -independent pathways. A reduction in antibody production was observed in normal neonates when they were foster-nursed by Rag-2(-/-) mothers. Thus, the maternal lymphocyte factors enhancing the immune responses in newborns were shown to be present in breast-milk.

Magnetic resonance imaging analysis on the relationship between anterior disc displacement and balancing-side occlusal contact

The purpose of this study was to evaluate the relationship between balancing-side occlusal contact patterns and the prevalence of the internal derangement of the temporomandibular joint (TMJ). Forty-one patients were used for the magnetic resonance image (MRI) analysis of TMJ and occlusal examination. Balancing-side occlusal contact patterns observed during mandibular lateral excursive movements were classified into the three following categories: group A, simultaneous balancing-side contact, group B, balancing-side contact (with clenching only) and Group C, no balancing-side contact (with or without clenching). By the occlusal examination of 57 sides, 31.6% showed group A, 8.8% showed group B and 59.6% showed group C contact. Group A could not be observed in the patient group with normal disc position. In the disc displacement group, the prevalence of group A, group B and group C were 40.9, 6.8 and 52.3%, respectively. The higher prevalence of simultaneous balancing-side contact was revealed to be associated with articular disc dislocation.

Spinorphin as an endogenous inhibitor of enkephalin-degrading enzymes: roles in pain and inflammation

It is possible that enkephalins are involved in the pain-modulating mechanism in the spinal cord. Enkephalins, however, are short-lived, being rapidly degraded by various endogenous enzymes. Many substances that inhibit enkephalin-degradation have been investigated and it has been reported that some inhibitors (e.g. kelatorphan and RB101) alone showed anti-nociceptive activity. We found an endogenous factor that modulated enkephalin-degrading activity and purified it from bovine spinal cord based on its inhibitory activity toward enkephalin-degrading enzymes. Structural analysis revealed the factor to be Leu-Val-Val-Tyr-Pro-Trp-Thr and it was named spinorphin. It has been found that spinorphin inhibited the activity toward various enkephalin-degrading enzymes from monkey brain, especially dipeptidyl peptidase III (DPPIII, Ki=5.1 x 10(-7) M). Recently we reported that this inhibitor significantly inhibited bradykinin (BK)-induced nociceptive flexor responses. Importantly, the mode of inhibition to BK-responses by spinorphin was different from the case with morphine. The morphine-induced blockade of BK-response was attenuated by pertussis toxin treatment, whereas that of spinorphin was not. We also have reported roles for spinorphin in inflammation. Spinorphin significantly inhibited the functions of polymorphonuclear neutrophils (PMNs) by suppressing the binding of fMLF to its receptor on PMNs. Further, this inhibitor suppressed the carrageenan-induced accumulation of PMN in mouse air pouches after intravenous administration. These results indicate that spinorphin may be an endogenous anti-inflammatory regulator. The possible role of spinorphin and its analog as regulators in pain and inflammation will be discussed.

Presence of a novel subset of NKT cells bearing an invariant V(alpha)19.1-J(alpha)26 TCR alpha chain

CD1d-deficient (CD1d-/-) mouse lymphocytes were analyzed to classify the natural killer T (NKT) cells without reactivity to CD1d. The cells bearing a V(alpha)19.1-J(alpha)26 (AV19-AJ33) invariant TCR alpha chain, originally found in the peripheral blood lymphocytes, were demonstrated to be abundant in the NK1.1+ but not NK1.1- T cell population isolated from CD1d-/- mice. Moreover, more than half (11/21) of the hybrid cell lines established from CD1d-/- NKT cells expressed the V(alpha)19.1-J(alpha)26 invariant TCR alpha chain. The expression of the invariant V(alpha)19.1-J(alpha)26 mRNA was absent in beta2-microglobulin-deficient mice. Collectively, the present findings suggest the presence of a second NKT cell repertoire characterized by an invariant TCR alpha chain (V(alpha)19.1-J(alpha)26) that is selected by an MHC class I-like molecule other than CD1d.

Evolution of CHR-2 SINEs in cetartiodactyl genomes: possible evidence for the monophyletic origin of toothed whales

Short interspersed repetitive elements (SINEs) are a kind of retroposons dispersed among the eukaryotic genomes. Previously, we isolated and characterized a new SINE family, named CHR-2, members of which are distributed in the genomes of cetaceans, hippopotamuses, and ruminants. We analyzed systematically more than a hundred members of the CHR-2 SINEs, which were isolated from the genomes of cetaceans and cow, together with the additional data available in the DNA databases, and showed that these SINEs are divided into at least five distinct subfamilies that share diagnostic nucleotides and/or deletions. A hybridization analysis clearly demonstrated that, among these five subfamilies, two subfamilies, named CD and CDO, are specific to cetaceans and toothed whales, respectively. We reconstruct the evolutionary history of the CHR-2 SINEs during evolution of cetartiodactyl genomes.

Maintenance of condylar position using an occlusal splint after mechanical vibrating-traction of the TMJ

Although adequate relief of excess mechanical loading to the joint has been accepted as one of the important treatment concepts in the orthopaedic field, a treatment method for the temporomandibular joint (TMJ) to relieve excess mechanical loading has not yet been established. This study aimed to clarify the effect of an occlusal splint on the maintenance of the distracted condylar position achieved by vibrating-traction method. Vibrating dynamic traction force was applied for 5 min to the right TMJ using vibrating-traction apparatus. A flat stabilization splint was adjusted to keep the mandibular position and the condylar displacement was evaluated for 6 h after the dynamic traction procedure. Mean vertical displacement of the mandibular right first molar immediately after the vibrating-traction for the six subjects was 156 microm (ranging from 141 to 179 microm). The calculated mean condylar displacement immediately after the traction was 480 mum and could be kept to be 381 mum even after 6 h by wearing the flat stabilization splint. From the results of this study, it was revealed that the mechanically tracted condylar position could be maintained by a flat occlusal splint. It was suggested that the vibrating-traction method followed by the provision of occlusal support might have a possibility to work as a mechanical relieving procedure for the TMJ.

Inhibition of angiogenesis by humulone, a bitter acid from beer hop

On the basis of our previous finding that humulone, a bitter acid from beer hop extract, was a potent inhibitor of bone resorption and inhibited the catalytic activity of cyclooxygenase-2 (COX-2) and more potently the transcription of the COX-2 gene, we examined the effect of humulone on angiogenesis, using chick embryo chorioallantoic membranes (CAMs) and vascular endothelial and tumor cells. Humulone significantly prevented in vivo angiogenesis in CAM in a dose-dependent manner with an ED(50) of 1.5 microg/CAM. Humulone also inhibited in vitro tube formation of vascular endothelial cells. Moreover, it suppressed the proliferation of endothelial cells and the production of vascular endothelial growth factor (VEGF), an angiogenic growth factor, in endothelial and tumor cells. Thus, humulone is a potent angiogenic inhibitor, and may be a novel powerful tool for the therapy of various angiogenic diseases involving solid tumor growth and metastasis.

Insight into the mechanism of trypanosome lytic factor-1 killing of Trypanosoma brucei brucei

It has been known for almost a century that normal human serum can lyse the extracellular blood parasite Trypanosoma brucei brucei. This process is a result of a non-immune killing factor in human sera known as trypanosome lytic factor (TLF). In this work, we demonstrate that killing of T. b. brucei by trypanosome lytic factor-1 (TLF-1) in vitro is inhibited by the lipophyllic iron chelator, LI, the lipophyllic antioxidant DPPD, and the protease inhibitors antipain and E64. Thus TLF-1 killing likely requires iron, oxidants, and serine and cysteine proteases. Furthermore, we demonstrate that TLF-1 mediated lysis causes measurable peroxidation in T. brucei lipids via a reaction that is inhibited by DPPD, weak bases, and human haptoglobin. We hypothesize that TLF-1 lysis requires intracellular factors within the trypanosome including high intracellular H2O2 and high polyenoic lipid concentrations, lysosomal acidification and proteases, and intracellular iron sources. The data presented supports the hypothesis that the combination of these factors with TLF-1 inside the lysosome results in lysosomal membrane breakdown, release of the lysosomal contents, and subsequent autodigestion of the cell.

Modulation of event-related potentials in normal human subjects by visual divided attention to spatial and color factors

We investigated how visual event-related potentials (ERPs) are modulated by visual divided attention using an S1-S2 paradigm. Stimulus S2 consisted of non-target stimuli (Stimulus 1, 2, 3) and a target stimulus (Stimulus 4). The spatial/color factor was compared between S1 and S2: same/same (Stimulus 1); same/different (Stimulus 2); different/same (Stimulus 3); and different/different (Stimulus 4). The P1/N1 (90 approximately 150 ms) showed significantly greater amplitude in Stimulus 3 than in Stimuli 1 and 2. The N2 (230 approximately 290ms) showed significantly greater amplitude in Stimulus 2 than in Stimuli 1 and 3. We assumed that the P1/N1 was related to spatial attention, enhanced by alterations to the spatial factor, and that the N2 was related to color attention, enhanced by alterations to the color factor.

Hodgkin's disease preceded by unique neurological symptoms

This is the first case report of Hodgkin's disease (HD) which showed both remission and exacerbation of neurological signs before a confirmed diagnosis of HD. The episodes occurred three times and multiple lesions were involved. Immunoabsorption plasmapheresis and double filtration plasmapheresis were effective for the first episode, whereas, corticosteroids partly improved the second and third episodes. Fever and lymph node swelling were apparent afterward and she was diagnosed as having HD from a supraclavicular lymph node biopsy. The remaining neurologic deficits responded to chemotherapy and radiotherapy. The neurological symptoms were considered as a paraneoplastic syndrome of HD.

The lysosomal targeting and intracellular metabolism of trypanosome lytic factor by Trypanosoma brucei brucei

Trypanosome lytic factor (TLF) provides innate protection for humans against infection by the animal pathogen Trypanosoma brucei brucei but not against the agent of human African sleeping sickness, Trypanosoma brucei rhodesiense. TLF exists in two forms, TLF-1 and TLF-2. Prior studies suggested that TLF-1 causes lysosomal disruption and subsequent cell death in T. b. brucei. Here we confirm the lysosomal targeting of TLF-1 by immunolocalization with the trypanosome lysosomal membrane protein p67, and by co-fractionation of radiolabelled TLF-1 with lysosomal enzymes. In addition, pulse-chase studies indicate that TLF-1 is not degraded within the lysosome as compared to the host protein transferrin. In TLF-1 treated cells, transferrin is degraded normally, indicating that lysosomal proteases remain active during the early phase of TLF-1 treatment but fail to degrade TLF-1. Following endocytosis a TLF lipoprotein appears to undergo disulfide bond reduction prior to entering the lysosome. Results presented here indicate that TLF-1 lipoproteins are targeted to the lysosome but are resistant to trypanosome lysosomal proteases.

[Treatment for recurrent paradoxical brain embolism through the patent foramen ovale]

We report here two patients with recurrent paradoxical brain embolism through the patent foramen ovale(PFO). The TIAs, which occurred frequently under antiplatelet therapy, resolved soon after commencing the anticoagulation therapy. Case 1, a 57-year-old woman, was diagnosed as having lacunar brain infarction and was treated with ticlopidine hydrochloride. Eleven months later, she suffered from frequent TIAs. Anticoagulation therapy was started after the presence of PFO was documented on transesophageal echocardiography(TEE). Thereafter, her TIA disappeared. Case 2 was a 67-year-old man with a history of lacunar brain infarction. Although he was treated with aspirin for 9 months, he showed transient monoplegia in his right leg. His TEE study also revealed the presence of PFO. After the anticoagulation therapy reached the proper level(PT-NR = 2), he never experienced the recurrence of TIA. If the antiplatelet therapy failed to prevent the recurrence of TIA, it is recommended to find out the presence of PFO which is a potential source of paradoxical brain embolism. In such a case, anticoagulation therapy should be instituted.

Identification of candidate mitochondrial RNA editing ligases from Trypanosoma brucei

Most mitochondrial genes of Trypanosoma brucei do not contain the necessary information to make translatable mRNAs. These transcripts must undergo RNA editing, a posttranscriptional process by which uridine residues are added and deleted from mitochondrial mRNAs. RNA editing is believed to be catalyzed by a ribonucleoprotein complex containing endonucleolytic, terminal uridylyl transferase (TUTase), 3' uridine-specific exonucleolytic (U-exo), and ligase activities. None of the catalytic enzymes for RNA editing have been identified. Here we describe the identification of two candidate RNA ligases (48 and 52 kDa) that are core catalytic components of the T. brucei ribonucleoprotein editing complex. Both enzymes share homology to the covalent nucleotidyl transferase superfamily and contain five key signature motifs, including the active site KXXG. In this report, we present data on the proposed 48 kDa RNA editing ligase. We have prepared polyclonal antibodies against recombinant 48 kDa ligase that specifically recognize the trypanosome enzyme. When expressed in trypanosomes as an epitope-tagged fusion protein, the recombinant ligase localizes to the mitochondrion, associates with RNA editing complexes, and adenylates with ATP. These findings provide strong support for the enzymatic cascade model for kinetoplastid RNA editing.

Major sites for the differentiation of V alpha 14(+) NKT cells inferred from the V-J junctional sequences of the invariant T-cell receptor alpha chain

CD1d-restricted mouse NK1.1(+) TCR alpha beta(+) natural killer T (NKT) cells predominantly use an invariant TCR alpha chain encoded by V alpha 14 and J alpha 281 gene segments with a one-nucleotide N region. We found that NKT cells generated in the culture of fetal liver precursors possessed V alpha 14-J alpha 281 junctions that could be produced without the action of terminal deoxyribonucleotidyl transferase (TdT), indicating that NKT cells derived from fetal liver precursors are distinguishable from those from adult precursors with TdT expression. In fact, the frequency of the fetal-form sequences decreased with ageing. Surprisingly, the fetal-type sequences were predominantly observed in the lymphoid organs of athymic mice with the exception of bone marrow, where a sequence peculiar to the organ, with TdT-involved conversion from the invariant junction, was frequently present. These findings suggest that there are two independent sites of V alpha 14(+) NKT cell development, the hematopoietic organs throughout life (the developing liver and adult bone marrow) and, principally, the mature thymus.

A novelCLCN1 mutation: P480T in a Japanese family with Thomsen's myotonia congenita

At least 50 disease-causing mutations in the skeletal muscle voltage-gated chloride channel gene (CLCN1), almost all of which originate from Caucasian families, have been identified. We investigated a Japanese family with Thomsen's myotonia congenita that included 16 affected individuals (8 men and 8 women) through five generations. Polymerase chain reaction (PCR)-single-strand conformation polymorphism (SSCP) screening of 11 members showed an aberrant conformer in exon 13 of CLCN1 complementary DNA (cDNA) in 8 affected and 1 unaffected members. By sequence analysis, we identified a C-to-A transition at nucleotide position 1438, resulting in a substitution of proline for threonine at amino acid position 480 (P480T), the same position of the original mutation (P480L) in Thomsen's disease. The P480T mutation was novel and absent in 100 normal controls. Seven of the 8 affected individuals were heterozygous; another, from affected parents, was homozygous. Clinically, myotonia in the homozygous patient was more severe than that in heterozygous patients, probably due to the gene dosage effect. On a long-train nerve-stimulation test at a rate of 3 Hz, M-wave responses in the homozygous patient showed marked decrement followed by recovery. In contrast, the heterozygous patients showed just a slight decrement or no changes, and none of 2 patients with myotonic muscular dystrophy or 2 normal controls revealed any decrement. Thus, the long-train nerve-stimulation test at a low stimulus frequency may be a useful tool to assess the disease-severity/genotype relationship in myotonia congenita.