Neuroprotective effect of cyclic GMP against radical-induced toxicity in cultured spinal motor neurons

We have previously reported that nitric oxide-related cyclic guanosine-3',5'-monophosphate (GMP) protected spinal nonmotor neurons, but not motor neurons against chronic glutamate-induced toxicity, which is associated with selective motor neuronal death after glutamate stress. In this report, we investigated the effect of cyclic GMP against reactive oxygen species (ROS)-induced toxicity in cultured neurons from embryonic rat spinal cords. Pretreatment with a cGMP analogue, 8-bromoguanosine monophosphate (8br-cGMP), for 12-24 hours protected both spinal motor neurons and nonmotor neurons against injury induced by either hydrogen peroxide (H(2)O(2)), or a glutathione depletor, L-buthionine-[S,R]-sulfoximine (BSO). This protective effect was reversed by coadministration with the cGMP-dependent protein kinase (PKG) inhibitor Arg-Lys-Arg-Ala-Arg-Lys-Glu. Interestingly, when cultures were exposed to BSO for 24 hours to allow irreversible inhibition of glutathione synthesis, 8br-cGMP protected only nonmotor neurons. Our results indicate that cGMP attenuates oxidative injury to cultured spinal neurons, in a mechanism associated with glutathione synthesis.

[First documentation of transfusion-associated babesiosis in Japan]

A 40-year-old man received blood transfusion in December 1998 because of gastric bleeding from a peptic ulcer. One month later, he developed febrile hemolytic anemia. Administration of high doses of glucocorticoid significantly reduced the hemolysis, but did not cure the disease. To investigate the cause of the hemolysis, the patient was transferred to our hospital in May 1999. Giemsa-stained peripheral blood smears showed Babesia parasites in the red blood cells (RBC), and PCR analysis confirmed the presence of Babesia microti DNA. The parasitemia disappeared hematologically after 2 weeks of quinine and clindamycin therapy. However, parasite DNA was still detectable in the RBC. Although treatment with oral atovaquone was given for 2 weeks, parasitemia and febrile hemolysis recurred within a month after the last treatment. Fortunately, complete remission was obtained after a second 12-week course of therapy with quinine and clindamycin. PCR analysis revealed asymptomatic Babesia infection in one of eight samples from the original blood donor. The initial steroid therapy given to the patient without an accurate diagnosis seemed to have delayed augmentation of the specific antibodies (IgG) against Babesia microti, thus prolonging the parasitemia after the initial acute stage of babesiosis.

Ataxia-telangiectasia in the Japanese population: identification of R1917X, W2491R, R2909G, IVS33+2T-->A, and 7883del5, the latter two being relatively common mutations

We analyzed the data regarding six Japanese ataxia-telangiectasia (A-T) patients from four unrelated families, at the DNA level, to search for possible common mutations in the Japanese population. Among eight mutant alleles in the four families, c. 4612del165 (exon 33 skipping) was identified in two alleles, and c. 5749A to T (R1917X), c. 7471T to C (W2491R), c.7883de15, and c. 8725A to G (R2909G) were identified in one allele each. We found no mutations in the other two alleles. The IVS33 + 2T-->A mutation was identified at the genomic level as the cause of exon 33 skipping. We also identified the IVS33 + 2T-->A mutation in a Japanese patient ATL105 who was previously found to be a homozygote of c. 4612del165. W2491R and R2909G mutations were not detected in more than 100 control Japanese alleles. The latter is located in a highly conserved PI-3 kinase domain and is a completely conserved residue among ATM-related proteins. Taken together with previously documented mutations in five other Japanese A-T patients, IVS33 + 2T-->A and 7883del5 were identified in four and five alleles, respectively, in a total of 18 mutant alleles of Japanese A-T patients. These results suggest that these two mutations are relatively common mutations in the Japanese population.

Effect of DNA/liposome mixing ratio on the physicochemical characteristics, cellular uptake and intracellular trafficking of plasmid DNA/cationic liposome complexes and subsequent gene expression

In order to identify the important factors involved in cationic liposome-mediated gene transfer, in vitro transfection efficiencies by plasmid DNA complexed with DOTMA/DOPE liposomes at different DNA/liposome mixing ratios were evaluated using four types of cultured cells with respect to their physicochemical properties. Significant changes were observed in the particle size and zeta potential of the complexes as well as in their structures, assessed by atomic force microscopy, which depended on the mixing ratio. In transfection experiments, except for RAW 264.7 cells (mouse macrophages), efficient gene expression was obtained in MBT-2 cells (mouse bladder tumor), NLH3T3 cells (mouse fibroblasts) and HUVEC (human umbilical vein endothelial cells) at an optimal ratio of 1:5, 1:7.5 or 1:5, respectively. On the other hand, cellular uptake of the [32P]DNA/liposome complexes increased in all cell types with an increase in the mixing ratio, which was not reflected by the transfection efficiency. The cellular damage determined by MTT assay was minimal even at the highest DNA/liposome ratio (1:10), indicating that the lower gene expression level at the higher ratio was not due to cytotoxicity induced by the complex. An ethidium bromide intercalation assay showed that the release of plasmid DNA from the complex, following the addition of negatively charged liposomes, was restricted as the mixing ratio increased. Furthermore, confocal microscopic studies using HUVEC showed that the 1:5 complexes exhibited a dispersed distribution in the cytoplasm whereas a punctuate intracellular distribution was observed for the 1:10 complexes. This suggests that there was a significant difference in intracellular trafficking, probably release from the endosomes or lysosomes, of the plasmid DNA/cationic liposome complexes between these mixing ratios. Taken together, these findings suggest that the DNA/liposome mixing ratio significantly affects the intracellular trafficking of plasmid DNA complexed with the cationic liposomes, which is an important determinant of the optimal mixing ratio in cationic liposome-mediated transfection.

Immunolocalization of human p14(ARF) to the granular component of the interphase nucleolus

The human p14(ARF) protein is encoded by an alternative transcript from the INK4a/ARF locus on chromosome 9p21, a locus frequently afflicted in human tumors. By use of two novel specific antisera against p14(ARF) we show that the protein is localized mainly in nucleoli but also in the nucleoplasm. Transfection of full-length and deletion mutant GFP-p14(ARF) fusion proteins confirmed this subcellular localization and assigned the nucleolar localization signal to the exon 2-encoded C-terminal region. In order to determine p14(ARF) expression in human tumor cells, we examined p14(ARF) in 32 tumor cell lines by immunofluorescence staining. Nucleolar p14(ARF) was detected in 10 lines, all of which lacked functional p53. Double immunostaining with p14(ARF) and B23/nucleophosmin or fibrillarin antibodies using 3D microscopy revealed that p14(ARF) is located mainly in the granular component of the nucleolus. p14(ARF) was also found in distinct granular aggregates scattered throughout the nucleoplasm. RNase digestion or selective inhibition of rRNA transcription by low doses of actinomycin D caused nucleoplasmic translocation of p14(ARF). This indicates that the nucleolar localization of p14(ARF) is dependent on ongoing transcriptional activity in intact functional nucleoli.

Inhibitory effect of cepharanthine on fibronectin production in growth factor-stimulated rat mesangial cells

We examined the effect of cepharanthine, a biscoclaurine alkaloid, on extracellular matrix production in rat mesangial cells in response to platelet-derived growth factor (PDGF) or transforming growth factor-beta (TGF-beta). Stimulation of the cells with PDGF increased the amounts of fibronectin, one of extracellular matrix components. Pretreatment with cepharanthine (0.1-2 microM) suppressed the PDGF-stimulated increase in fibronectin in a dose-dependent manner. At a concentration of 2 microM, the alkaloid almost completely suppressed the production. Under the conditions, the alkaloid inhibited tyrosine phosphorylation of several proteins including PDGF beta receptor in PDGF-stimulated cells, and also tyrosine kinase activity of the receptor prestimulated with PDGF in a cell-free assay system. Furthermore, cepharanthine suppressed TGF-beta-stimulated fibronectin production at the same concentration ranges. Our results suggest that cepharanthine inhibits fibronectin production induced by growth factors, probably through suppression of receptor autophosphorylation.

Characterization of human polymorphic DNA repair methyltransferase

The O6-methylguanine-DNA methyltransferase (MGMT) is a critical defence against alkylation-induced mutagenesis and carcinogenesis. More than a 20-fold interindividual difference in the MGMT activity is known to exist among human cultured fibroblasts. We previously reported three allelic variants of the human MGMT gene, namely V1, V2, and V3. Both V1 and V2 carry amino acid substitutions, Leu84Phe and Trp65Cys, respectively, while V3 has a silent mutation. In order to reveal the pharmacogenetic and ecogenetic significance of polymorphism in the human MGMT gene, we investigated the in-vivo characteristics of V1 and V2 methyltransferase enzyme. Escherichia coli strain KT233 (ogt-, ada-) and mer- HeLa MR cells carrying a V1 sequence exhibited almost the same level of sensitivity against N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), as did those with a wild-type sequence. The level of methyltransferase protein in those cells was essentially the same as for the wild-type and V1 samples. On the other hand, E. coli and human cells expressing V2 cDNA showed a significantly reduced level of survival. In these cells, V2 protein was hardly detected, even though mRNA was produced normally. An in-vitro translation experiment revealed that the V2 sequence had the potential to produce methyltransferase protein, as did the wild-type and V1 sequences. There was also evidence for a small amount of V2 protein being produced but rapidly degraded, thus implying that the V2 molecule is unstable in vivo. Using purified recombinant proteins, we estimated the kinetic values of wild-type and variant form of enzymes, which would support these views. From these results, we concluded that the wild-type and V1 protein have similar enzymatic and physicochemical properties, while V2 protein is considered to be unstable and rare.

T-cell-specific expression of kinase-defective Eph-family receptor protein, EphB6 in normal as well as transformed hematopoietic cells

Although most kinase-defective growth factor receptor proteins are associated with pathogenic conditions, a kinase-defective Eph-family receptor protein, EphB6, is expressed in normal human tissues. We generated monoclonal antibodies specific for human EphB6 to characterize its expression on human hematopoietic cells. A very small population of normal human peripheral white blood cells (0.57 +/- 0.07%, n = 12) expressed EphB6. The EphB6-positive cells were CD2+, CD7+, CD3+ and CD4+ or CD8+ lymphocytes, but they did not express CD19 or CD11b. In human bone marrow, only 1.5 +/- 0.19% of lymphocytes expressed EphB6. Compared with the expression in peripheral lymphocytes, prominent expression of EphB6 protein was demonstrated in CD4+CD8+ double-positive mouse thymocytes. The T-cell lineage-specific expression was strictly conserved in human leukemia/lymphoma cells. Among T-cell-derived leukemia cells, the expression level of EphB6 seemed to decrease with maturation of the cells. These results suggest that EphB6 expression is regulated in T-cell development.

Feasibility of high-dose chemotherapy without stem cell support as a first-line treatment for non-Hodgkin's aggressive lymphoma: a pilot study

A regimen which incorporates cyclophosphamide, doxorubicin, vincristine and prednisolone (CHOP) is the standard treatment for patients with non-Hodgkin's lymphoma (NHL), but it has not been effective in patients with aggressive NHL who are at high risk. The aim of the present trial was to investigate the feasibility of high-dose chemotherapy (HDC) without stem cell support as a first-line treatment. The primary endpoint was a complete remission rate. The second endpoint was survival. Fourteen patients with aggressive NHL entered the study and were treated according to the K93 protocol (3 cycles of CHOP, high-dose etoposide and ifosfamide, and high-dose methotrexate) Eleven patients (79%) achieved complete remission (CR) and two (14%) achieved partial remission (PR). Overall survival (OS) after five years was 79%. The actuarial five year disease free survival (DFS) for the eleven cases of CR was 75%. During chemotherapy, grade IV hematologic toxicity was observed in all patients and grade IV non-hematologic toxicity in only one patient, who experienced oral ulcers. Peripheral blood stem cell (PBSC) apheresis was performed in eight cases. One harvesting was enough to provide an adequate number of CD34+ cells for the subsequent PBSC transplantation (PBSCT). In conclusion our study confirmed the efficacy of the K93 protocol in obtaining a good response (CR + PR) rate and a very good DFS rate in most cases of aggressive NHL, with acceptable toxicity. This regimen may improve the outcome in cases of aggressive NHL without stem cell support. It seems worthwhile to conduct a randomized controlled study comparing the K93 protocol with the standard CHOP regimen.

Immunoblot analysis for laboratory diagnosis of ataxia-telangiectasia: use of Epstein-Barr virus-transformed or phytohemagglutinin-stimulated lymphoblasts for detection of ATM protein

Ataxia-telangiectasia (A-T) is a genetic disorder characterized by a progressive ataxia, immunodeficiency, neurological abnormalities, hypersensitivity to ionizing radiation, and predisposition to cancer. The gene responsible for A-T (ATM) has been cloned and shown to code for a 350 kDa polypeptide containing 3,056 amino acid residues. Detection of ATM mutations for laboratory diagnosis of A-T is laborious and not practical, unless there are common mutations in a population. We describe here immunoblot analysis for the detection of ATM in seven Japanese A-T patients from five families and in controls using ATM3BA antibody. ATM protein was routinely and clearly detected in Epstein-Barr virus (EBV)-transformed or phytohemagglutinin (PHA)-stimulated lymphoblasts from controls. However, it could not be detected consistently in unstimulated peripheral blood mononuclear cells (PBMCs) from controls. We also detected ATM protein in control fibroblasts, but the background was relatively higher than in control lymphoblasts. ATM protein was not detected or dramatically decreased in EBV-transformed lymphoblasts from all seven patients tested and in fibroblasts from one patient. Immunoblot analysis using EBV-transformed or PHA-stimulated lymphoblasts represents a useful approach for laboratory diagnosis for A-T. The latter is especially preferable since it takes only 3 days to obtain sufficient cells for analysis.

Temperature-sensitive gating of cation current in guinea pig ileal muscle activated by hyperpolarization

The temperature dependence of hyperpolarization-activated current (I(h)) was investigated in freshly isolated guinea pig ileal smooth muscle cells, using the nystatin-perforated whole cell recording technique. Hyperpolarizing pulses (-50 to -120 mV) from -40 mV evoked time-dependent inward rectifying currents with a reversal potential of -33 mV and a slow activation time course well approximated by a single exponential. The properties of these currents, such as steady-state variables, dependence on external K, modification by norepinephrine, and blockade by Cs or ZD-7288, coincide well with those of the "classical" I(h) discovered in the sinoatrial node. Raising the temperature (range: 22-33 degrees C) accelerated the activation time course of this I(h) and shifted its 50% activation potential positively (12 mV/10 degree) with much less change in the maximum conductance. Based on a simple closed-open model, this can be explained by a high temperature dependence of the opening rate constant (temperature coefficient: 3.4). The activation profile of reconstructed I(h) at 36 degrees C suggests that a considerable overlap could occur between the ranges of I(h) activation and physiological membrane potential.

Mutations of the IL-12 receptor beta2 chain gene in atopic subjects

Interleukin-12(IL-12) promotes cell-mediated Th1 responses and production of IFN-gamma that downregulates IgE production. The signal of IL-12 is transduced through the IL-12 receptor (IL-12R) and Stat4. Twenty-four of 75 atopic individuals with high levels of IgE showed insufficient IFN-gamma production by peripheral blood mononuclear cells (PBMCs) following stimulation with IL-12 but not that with phytohemagglutinin (PHA). Interestingly, 10 of the above 24 subjects were found to be heterozygous for truncated (2496 del 91) or missense (1577 A to G and 2799 A to G) mutations of IL-12R beta2 chain gene (IL-12R beta2). Insufficient phosphorylation of Stat4 was also demonstrated in these 10 individuals. This is the first report showing that reduced IFN-gamma production following IL-12 stimulation is associated with the heterozygous IL-12R beta2 mutations in atopic subjects.

Studies on functions of the 63-kDa A- and 74-kDa B'(delta)-regulatory subunits in human erythrocyte protein phosphatase 2A: dissociation and reassociation of the subunits

A heterodimeric form, CA, of protein-serine/threonine phosphatase (PP) 2A purified from human erythrocytes was dissociated into a 34-kDa catalytic subunit C and 63-kDa inactive subunit A by Sephacryl S-200 gel filtration in the presence of 6 M urea. Reassociation of the C- and A-subunits in the absence of urea suppressed the PP activity of the C subunit toward phosphorylase a, P-H2B histone, and P-H1 histone in the presence or absence of 20 mM MnCl(2) or 50 mM Mg(CH(3)COO)(2), but stimulated the PP activity toward P-H1 histone in the presence of 200 mM NaCl and the Mn(2+)-dependent protein-tyrosine phosphatase (PTP) activity toward P-Tyr-Glu copolymers. The 74-kDa inactive B'(delta) subunit was isolated from a heterotrimeric form, CAB'(delta), of PP2A partially purified from human erythrocytes, by heparin-Sepharose column chromatography. The B'(delta) subunit reassociated with CA and suppressed the PP- and PTP-activities of CA. The B'(delta) subunit did not associate with the isolated C subunit directly, and had no effect on the activities of the C subunit, indicating that the A subunit is essential for the association of the B'(delta) subunit with CA and the resulting suppression of the PP- and PTP-activities.

Electrophysiological actions of a novel K(+) channel opener MCC-134 on rabbit portal vein smooth muscle

The effects of a newly synthesized K(+) channel opener, 1-[4-(1H-imidazol-1-yl)benzoyl]-N-methylcyclobutane-carbothioamide (MCC-134) on membrane currents and intracellular Ca(2+) mobilization were investigated in rabbit portal vein smooth muscle cells. Under voltage-clamped conditions, MCC-134 dose-dependently induced K(+)-selective currents (I(MCC); EC(50) 5.3 microM) showing little desensitization but fast deactivating properties on washout of drugs. I(MCC) was completely blocked by 10 microM glibenclamide, not affected by iberiotoxin (500 nM), charybdotoxin (200 nM) or apamin (500 nM), and inhibited by nonspecific K(+) channel blockers, tetraethylammonium (1-10 mM), 4-aminopyridine (0.1-1 mM) and Ba(2+) (0.01-0.1 mM). Intracellularly applied nucleotide diphosphates (1 mM) were effective at maintaining I(MCC) (apparent potency; ADP<==GDP falling dotsIDP<UDP), whereas intracellular ATP exhibited a biphasic, i.e., augmentative and inhibitory effect(s) on I(MCC). Single channel activities of about 15 pS (40/140 mM extra-/intracellular K(+)) fully accountable for macroscopic I(MCC) were activated by MCC-134. MCC-134, at a concentration as high as 100 microM, suppressed voltage-dependent Ca(2+) and noradrenaline-induced cation currents, and concomitant elevations in the intracellular Ca(2+) concentration ([Ca(2+)](i)).

Psychological impact of informed consent in hospitalized cancer patients. A sequential study of anxiety and depression using the hospital anxiety and depression scale

Patients with cancer receive an explanation of their disease and the recommended treatment when they are asked to give informed consent (IC). In the course of this process patients suffer severe distress, including anxiety and depression, but physicians tend to underestimate it. The goal of this study was to reveal the magnitude of such stress and any changes to this during the IC process by means of the Hospital Anxiety and Depression (HAD) scale, a self-assessment scale. Of 171 in-patients newly diagnosed with lung cancer, 119 were assessable for serial HAD scale scores on admission, immediately after the IC process, and at 1 and again at 2 weeks after the IC. Both anxiety and depression scores increased significantly immediately after IC. Female patients had significantly higher anxiety and depression scores than males at 1 week after the IC. The patients with poor performance status demonstrated high anxiety scores on admission and immediately after the IC, and substantial depression persisted longer in these patients. The prevalence of high scores of more than 11 (judged as adjustment disorder or more severe state) immediately after the IC was 50% for anxiety and 31% for depression. The prevalence decreased significantly within 1 or 2 weeks, but 41% and 14% of the patients still showed high anxiety and depression scores, respectively. Physicians should be aware of these facts and pay special attention to their patients' psychological distress in routine clinical practice.

Time-course study of the levels of urinary leukotriene E4, serum thromboxane B2 and serum eosinophil cationic protein in spontaneous asthma attacks in five children

Leukotrienes thromboxanes, and eosinophil cationic protein (ECP) are chemical mediators involved in airway inflammation. We investigated time courses of urinary leukotriene E4 (LTE4), serum thromboxane B2 (TXB2) and serum ECP, together with blood eosinophil count during asthmatic attacks in five children. Just after the onset of an asthma attack, urinary LTE4 levels reflected the severity of the attack and decreased during the course of clinical improvement with various therapies; however, they did not change in the course of an attack in one of five patients. The other parameters showed less or no significant relation to clinical severity and improvements. Since LTE4 is a stable product from total cysteinyl leukotrienes, it appears to be one of important mediators in most asthma attacks in children. This study suggests that LTE4 is a useful marker for monitoring severity and improvement of spontaneous attacks of asthma.

Predominant distribution of nifedipine-insensitive, high voltage-activated Ca2+ channels in the terminal mesenteric artery of guinea pig

We have found nifedipine-insensitive (NI), rapidly inactivating, voltage-dependent Ca2+ channels (current, NI-I(Ca)) with unique biophysical and pharmacological properties in the terminal branches of guinea pig mesenteric artery, by using a whole-cell mode of the patch-clamp technique. The fraction of NI-I(Ca) appeared to increase dramatically along the lower branches of mesenteric artery, amounting to almost 100% of global I(Ca) in its periphery. With 5 mmol/L Ba2+ as the charge carrier, NI-I(Ca) was activated with a threshold of -50 mV, peaked at -10 mV, and was half-activated and inactivated at -11 and -52 mV, respectively, generating a potential range of constant activation near the resting membrane potential. The NI-I(Ca) was rundown resistant, was not subject to Ca(2+)-dependent inactivation, and exhibited the pore properties typical for high voltage-activated Ca2+ channels; Ba2+ is approximately 2-fold more permeable than Ca2+, and Cd2+ is a better blocker than Ni2+ (IC(50), 6 and 68 micromol/L, respectively). Relatively specific blockers for N- and P/Q-type Ca2+ channels such as omega-conotoxins GVIA and MVIIC (each 1 micromol/L) and omega-agatoxin IVA (1 micromol/L) were ineffective at inhibiting NI-I(Ca), whereas nimodipine partially (10 micromol/L; approximately 40%) and amiloride potently ( approximately 75% with 1 mmol/L; IC(50); 107 micromol/L) blocked the current. Although these properties are reminiscent of R-type Ca2+ channels, expression of the alpha(1E) mRNA was not detected using reverse transcriptase-polymerase chain reaction. These results strongly suggest the predominant presence of NI, high voltage-activated Ca2+ channels with novel properties, which may be abundantly expressed in peripheral small arterioles and contribute to their tone regulation.

Cytolytic mechanisms involved in non-MHC-restricted cytotoxicity in Chediak-Higashi syndrome

To determine the mechanisms responsible for the impaired lymphocyte-mediated cytotoxicity in Chediak-Higashi syndrome (CHS), we investigated the killing ability of peripheral blood lymphocytes (PBL) from three patients with CHS using several kinds of target cells that were sensitive to perforin, Fas ligand (FasL), and/or tumour necrosis factor-alpha (TNF-alpha). Freshly isolated CHS PBL did not kill K562 target cells, killing of which by normal PBL was perforin-dependent, as demonstrated by complete inhibition by concanamycin A (CMA), an inhibitor of perforin-based cytotoxicity. In contrast, the CHS PBL exhibited substantial cytotoxicity against Jurkat cells, which was only partially inhibited by CMA treatment but not by the addition of neutralizing anti-FasL or anti-TNF-alpha antibodies. IL-2-activated CHS PBL exhibited substantial levels of cytotoxicity against K562 and Jurkat cells, the levels being 74% and 83% of the respective normal control values, respectively. CMA treatment showed that while the cytotoxicity of IL-2-activated CHS PBL against K562 was largely dependent on perforin, that against Jurkat was largely not. IL-2-activated CHS PBL expressed FasL mRNA, and killed Fas transfectants. These findings indicate that CHS PBL have an ability to kill some target cells via a perforin-mediated pathway, especially when they are activated by IL-2. It was also demonstrated that CHS PBL can exert cytotoxicity against certain target cells by utilizing FasL and an undefined effector molecule other than perforin, FasL, or TNF-alpha.

Molecular and functional characterization of a novel mouse transient receptor potential protein homologue TRP7. Ca(2+)-permeable cation channel that is constitutively activated and enhanced by stimulation of G protein-coupled receptor

Characterization of mammalian homologues of Drosophila transient receptor potential protein (TRP) is an important clue to understand molecular mechanisms underlying Ca(2+) influx activated in response to stimulation of G(q) protein-coupled receptors in vertebrate cells. Here we have isolated cDNA encoding a novel seventh mammalian TRP homologue, TRP7, from mouse brain. TRP7 showed abundant RNA expression in the heart, lung, and eye and moderate expression in the brain, spleen, and testis. TRP7 recombinantly expressed in human embryonic kidney cells exhibited distinctive functional features, compared with other TRP homologues. Basal influx activity accompanied by reduction in Ca(2+) release from internal stores was characteristic of TRP7-expressing cells but was by far less significant in cells expressing TRP3, which is structurally the closest to TRP7 in the TRP family. TRP7 induced Ca(2+) influx in response to ATP receptor stimulation at ATP concentrations lower than those necessary for activation of TRP3 and for Ca(2+) release from the intracellular store, which suggests that the TRP7 channel is activated independently of Ca(2+) release. In fact, TRP7 expression did not affect capacitative Ca(2+) entry induced by thapsigargin, whereas TRP7 greatly potentiated Mn(2+) influx induced by diacylglycerols without involvement of protein kinase C. Nystatin-perforated and conventional whole-cell patch clamp recordings from TRP7-expressing cells demonstrated the constitutively activated and ATP-enhanced inward cation currents, both of which were initially blocked and then subsequently facilitated by extracellular Ca(2+) at a physiological concentration. Impairment of TRP7 currents by internal perfusion of the Ca(2+) chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid revealed an essential role of intracellular Ca(2+) in activation of TRP7, and their potent activation by the diacylglycerol analogue suggests that the TRP7 channel is a new member of diacylglycerol-activated cation channels. Relative permeabilities indicate that TRP7 is slightly selective to divalent cations. Thus, our findings reveal an interesting correspondence of TRP7 to the background and receptor stimulation-induced cation currents in various native systems.

The relationship of mismatch negativity to quantitative EEG and morphological findings in schizophrenia

The goal of the present study is to investigate the relationships of mismatch negativity (MMN) to other markers in schizophrenics; Quantitative EEG (QEEG), CT and psychopathological ratings. Thirty unmedicated patients (28.4+/-9.8 y, 20 M) including twenty neuroleptic-naive cases were divided into two groups before treatment; Group A consisted of ten patients with greater MMN amplitudes, while twenty patients with smaller ones were assigned to Group B. In QEEG, Group A showed a closer profile to healthy controls, indicating their function is less distorted. Group B showed greater power in slow wave, slow alpha and fast beta bands. Their greater slow wave may be implicated in cognitive impairment reflected by attenuated MMN as well as greater dilation in lateral ventricles and Sylvian fissures on CT. After pharmacological treatment with conventional neuroleptics, Group A's MMN decreased, whereas that of Group B increased. Furthermore, neuroleptics' EEG-effects observed in Group A were close to the reported profiles of healthy subjects, while those in Group B were distinct from them. Conclusively, MMN might have crucial associations to other measures underlying the brain pathology of schizophrenia. The diagnostic value of MMN as a trait-marker was discussed.

Relationship of mismatch negativity to background EEG and morphological findings in schizophrenia

The present study assessed relationships of mismatch negativity (MMN) of schizophrenics with other markers; quantitative EEG (QEEG), computed tomography (CT) and psychopathological ratings. Patients were divided into two groups before treatment; group A consisted of patients with greater MMN amplitudes while patients with lower ones were assigned to group B. In QEEG, group A showed no significant differences compared to controls, except for fast beta in the frontal region. The finding of well-preserved QEEG in group A indicates their function is less distorted than in group B, who showed greater powers in slow waves, slow alpha and fast beta bands. The greater slow-wave power of group B may be related to the cognitive impairment reflected by attenuated MMN, which corresponded to greater dilation in lateral ventricles and Sylvian fissures of group B on CT. Conclusively, MMN have crucial relationships to other biological markers representing the psychopathology of schizophrenia.

Induction of the human ARF protein by serum starvation

The ARF protein encoded by the alternative transcript of the INK4a gene inhibits cell growth by stabilization of p53. ARF is induced by activated oncogenes sucll as c-myc, E1A and E2F-1. We show here that ARF protein expression is also induced by serum deprivation in the human tumor cell line MDA-MB-157 and in the SV40 large T-immortalized keratinocyte line Rhek. This increase of expression was reversed by the addition of serum. ARF mRNA levels also increased after serum starvation, suggesting that ARF upregulation is mediated, at least in part, by increased transcription and/or mRNA stability. These results indicate that ARF responds not only to oncogenic hyper-proliferative signals but also to suboptimal growth conditions.