Effect of facial affect stimuli on auditory and visual P300 in healthy subjects

This study investigated whether or not P300 components are influenced by emotional affect such as sadness and pleasure in twenty healthy subjects and whether or not the P300 effects of facial affect stimuli are influenced by auditory and visual stimulus modalities. Written informed consent was taken from each subject before the study. Each subject was asked to stare at a simple picture of a facial expression (crying or smiling faces) during the auditory and visual oddball tasks. P300 amplitude and area were significantly larger when viewing a crying face (sadness) than a smiling face (pleasure) under both conditions with auditory and visual stimulus. P300 latency was significantly longer while viewing sadness than while viewing pleasure only with auditory stimuli. Reaction time was not changed by facial stimuli. Amplitude and area of P300 were significantly larger in women than men in their modalities, but the effects of facial affect on P300 amplitude and area in women were similar to those in men. These results suggest that amplitude and area of P300 with both modalities recorded while viewing sadness may induce larger attentional resource than pleasure. Gender was a less potent influence of facial expression on P300 parameters. The influence of facial emotion may be important to investigate the recognition processes of subjects.

Osteopontin facilitates angiogenesis, accumulation of osteoclasts, and resorption in ectopic bone

Osteoclastic bone resorption requires a number of complex steps that are under the control of local regulatory molecules. Osteopontin is expressed in osteoclasts and is also present in bone matrix; however, its biological function has not been fully understood. To elucidate the role of osteopontin in the process of osteoclastic bone resorption, we conducted ectopic bone implantation experiments using wild-type and osteopontin knockout mouse. In the wild-type group, bone discs from calvariae implanted ectopically in muscle were resorbed, and their mass was reduced by 25% within 4 weeks. In contrast, the mass of the bone discs from calvariae of osteopontin knockout mice was reduced by only 5% when implanted in osteopontin knockout mice. Histological analyses indicated that the number of osteoclasts associated with the implanted bones was reduced in the osteopontin knockout mice. As osteopontin deficiency does not suppress osteoclastogenesis per se, we further examined vascularization immunohistologically and found that the number of vessels containing CD31-positive endothelial cells around the bone discs implanted in muscle was reduced in the osteopontin knockout mice. Furthermore, sc implantation assays indicated that the length and branching points of the newly formed vasculatures associated with the bone discs were also reduced in the absence of osteopontin. In this assay, tartrate-resistant acid phosphatase-positive area of the bone discs was also reduced in the osteopontin knockout mice, indicating further the link between the osteopontin-dependent vascularization and osteoclast accumulation. The bone resorption defect could be rescued by topical administration of recombinant osteopontin to the bones implanted in muscle. These observations indicate that osteopontin is required for efficient vascularization by the hemangiogenic endothelial cells and subsequent osteoclastic resorption of bones.

XAFS study on the sulfidation mechanisms of Co-Mo catalysts supported on activated carbon and alumina: effect of complexing agent

The effect of nitrilotriacetic acid (NTA) as a complexing agent on the sulfidation mechanisms of Co-Mo catalysts supported on activated carbon and alumina was examined by the XAFS technique. The XAFS results revealed that NTA interacted with Co atoms and formed the Co-NTA interaction, while it showed almost no influence on the local structures around Mo atoms. The Co-NTA interaction suppressed the aggregation of cobalt atoms and the interaction between cobalt and alumina during sulfiding, and consequently promoted the formation of the Co-Mo-S phase.

Microencapsulation of pesticides and their improved handling safety

The purpose of pesticide formulations and recent requirements of pesticide industry are discussed, and the importance of research work on pesticide delivery systems, is pointed out. For this purpose, the microcapsules, as one of the typical controlled release formulations, play an important role. Handling safety of the pesticides is improved considerably by microencapsulation due to hazard and exposure reduction.

Characterization and subcellular localization of KCNQ1 with a heterozygous mutation in the C terminus

Numerous mutations in KCNQ1, a gene encoding the alpha -subunit of cardiac delayed rectifier potassium channels, have been found in long QT syndrome (LQTS). Among them, several mutations in the C terminus have been shown to cause autosomal recessive or subclinical autosomal dominant LQTS. Here, we report a heterozygous mutation, T587M, which is also in the KCNQ1 C-terminal domain. The same mutation was found in three independent probands that were clearly symptomatic with family history of cardiac sudden death. Functional assay using a heterologous expression system with a mammalian cell line (COS7 cells) revealed that the mutant displayed neither functional channels when expressed alone nor dominant-negative effect when co-expressed with wild-type (WT) KCNQ1. To examine the cellular trafficking of KCNQ1, green fluorescent protein (GFP) was tagged to the cytoplasmic C terminus of WT or mutant KCNQ1. This procedure did not affect the essential properties of expressed WT KCNQ1 channels. On confocal microscopic images, GFP-tagged WT KCNQ1 showed a plasma membrane fluorescence pattern, whereas the GFP-tagged mutant showed a perinuclear fluorescence pattern. Co-expression of the mutant with GFP-tagged WT KCNQ1 did not influence its normal cellular transport. Therefore, the T587M mutant cannot traffic to the plasma membrane and may form no subunit assembly with WT KCNQ1. These findings provide a novel molecular basis for the clinical finding that this C-terminal mutation produced a severe form of RWS-type LQTS.

CD34 expression on long-term repopulating hematopoietic stem cells changes during developmental stages

The CD34 antigen serves as an important marker for primitive hematopoietic cells in therapeutic transplantation of hematopoietic stem cells (HSC) and gene therapy, but it has remained an open question as to whether or not most HSC express CD34. Using a competitive long-term reconstitution assay, the results of this study confirm developmental changes in CD34 expression on murine HSC. In fetuses and neonates, CD34 was expressed on Lin(-)c-Kit(+) long-term repopulating HSC of bone marrow (BM), liver, and spleen. However, CD34 expression on HSC decreased with aging, and in mice older than 10 weeks, HSC were most enriched in the Lin(-)c-Kit(+)CD34(-) marrow cell fraction. A second transplantation was performed from primary recipients who were transplanted with neonatal Lin(-)c-Kit(+) CD34(high) HSC marrow. Although donor-type HSC resided in CD34-expressing cell fraction in BM cells of the first recipients 4 weeks after the first transplantation, the stem cell activity had shifted to Lin(-)c-Kit(+)CD34(-) cells after 16 weeks, indicating that adult Lin(-)c-Kit(+)CD34(-) HSC are the progeny of neonatal CD34-expresssing HSC. Assays for colony-forming cells showed that hematopoietic progenitor cells, unlike HSC, continue to express CD34 throughout murine development. The present findings are important because the clinical application of HSC can be extended, in particular as related to CD34-enriched HSC and umbilical cord blood HSC.

Human neutrophil functions in obstructive jaundice

BACKGROUND/AIMS

The effect of obstructive jaundice on neutrophil function has not been extensively studied. Therefore, the present study aimed at evaluating the effect of obstructive jaundice on human neutrophils.

METHODOLOGY

Twelve patients with obstructive jaundice due to common bile duct obstruction underwent endoscopic biliary drainage. Neutrophil functions (chemotaxis and superoxide anion generation) were evaluated before and 7 days after drainage.

RESULTS

Neutrophil chemotaxis in response to FMLP (formyl-methionyl-leucyl-phenylalanine) or interleukin-8 was abnormally increased before drainage, and was normalized after drainage. Similarly, enhanced superoxide anion generation in response to FMLP or phorbol myristate acetate before drainage was alleviated after drainage.

CONCLUSIONS

The results suggest neutrophil overactivity in patients with obstructive jaundice. The ameliorating effect of biliary drainage on neutrophil overactivity might play a role in the prevention of postoperative complications.

Grazing-exit X-ray spectrometry for surface and thin-film analyses

Electron-probe x-ray micro analysis (EPMA) and particle-induced x-ray emission analysis (PIXE) were performed under grazing-exit conditions. To control the exit angle (take-off angle), a new sample holder having a stepping motor was developed for grazing-exit EPMA. A carefully polished surface of a stainless-steal sample was measured. The surface of stainless steel is normally covered with a thin native oxide layer. The intensity ratio of Cr K(alpha) to Fe K(alpha) increases significantly at the grazing angle, becoming about 5-times larger at 0.2 degrees than at 40 degrees. This result indicates that grazing-exit EPMA is useful for surface analysis. In addition, a new PIXE equipment was developed for grazing-exit x-ray measurements. The sample is fixed and the x-ray detector is moved by applying a linear stage. Preliminary experimental results of grazing-exit PIXE are also shown.

Hemodialysis paradox: survey on the incidence rate of hepatocellular carcinoma in antihepatitis virus C-antibody-positive chronic hemodialysis patients

The prevalence of antihepatitis virus C (HCV) antibodies in chronic hemodialysis (HD) patients is higher than in normal populations, and yet hepatocellular carcinoma (HCC) is infrequent in chronic HD patients who are HCV antibody positive. In this study, we investigated the characteristics of HCV-antibody-positive patients with HCC on chronic HD. A total of 6,366 cases of HCV-antibody-positive patients on chronic HD therapy was analyzed on the basis of answers to questionnaires on the incidence rate of HCC in 314 Japanese dialysis institutions. HCC was a complication in 114 of 6,222 (1.8%) HCV-antibody-positive patients, and cirrhosis was a complication in 536 of 6,242 (8.6%). The incidence rate of both complications was significantly higher in males than in females, and the incidence rate in the chronic HD patients was much lower than in normal populations. Specific immunological status in patients on chronic HD therapy may be an important key for preventing the progression of chronic HCV hepatitis. However, further research is needed because this study was preliminary and excluded the type of HCV virus, pathological findings, and laboratory data.

Transient suppression of core-binding factor alpha 1 expression by basic fibroblast growth factor in rat osteoblast-like osteosarcoma ROS17/2.8 cells

Core-binding factor alpha 1 (Cbfa1) is considered a prerequisite transcription factor for osteoblastic differentiation, based on experiments performed in knock-out mice. Cbfa1 binding sequences have been located in the promoter regions of various osteoblast phenotype-related genes, which are also known to be regulated by fibroblast growth factor (FGF). To elucidate the molecular mechanisms of FGF regulation of osteoblasts, we investigated the effects of FGF on Cbfa1 expression in osteoblast-like cells. We found that basic FGF, at 10 ng/ml, suppressed Cbfa1 mRNA expression in ROS17/2.8 cells. To detect the two distinct mRNA species that give rise to Pebp2alphaA/Cbfa1 and Osf2/Til-1/Cbfa1, we used semi-quantitative reverse transcription-polymerase chain reaction analysis using specific sets of primers. This analysis indicated that treatment with FGF transiently decreased the abundance of only the Osf2/Til-1/Cbfa1 isoform and not the Pebp2alphaA/Cbfa1 isoform in ROS17/2.8 cells. The suppression of Osf2/Til-1/Cbfa1 was time dependent and was observed up until 48h, and Cbfa1 mRNA levels then returned closer to control levels. Dose-dependent suppression by FGF was observed only with regard to mRNA levels of Osf2/Til-1/Cbfa1 and not for Pebp2alphaA/Cbfa1 mRNA. These data indicate that FGF suppresses Cbfa1 mRNA expression and that the Osf2/Til-1/Cbfa1 isoform is the specific target of FGF regulation in osteoblastic osteosarcoma ROS17/2.8 cells.

Phylogenetic relationships among wild and cultivated Tartary buckwheat(Fagopyrum tataricum Gaert.) populations revealed by AFLP analyses

Phylogenetic relationships among cultivated landraces and natural populations of wild subspecies of Tartary buckwheat were investigated at the individual level by constructing a phylogenetic tree based on amplified fragment length polymorphism (AFLP) markers. Seven individuals from seven cultivated landraces and 35 individuals from 21 natural populations of wild subspecies were utilized for AFLP analyses. Three groups were recognized: (1) all cultivated landraces and wild subspecies from northern Pakistan, central and eastern Tibet, and northwestern Yunnan, (2) wild subspecies from central and southern Sichuan, (3) wild subspecies from northern Sichuan and eastern Tibet. It was concluded that cultivated Tartary buckwheat probably originated in eastern Tibet or northwestern Yunnan in China.

Disopyramide and its metabolite enhance insulin release from clonal pancreatic beta-cells by blocking K(ATP) channels

In an insulin-secreting pancreatic beta-cell line (MIN6), insulin release was caused by disopyramide, an antiarrhythmic drug with Na-channel blocking action, and its main metabolite mono-isopropyl disopyramide (MIP). Insulin secretion, measured as immunoreactive insulin (IRI), was accelerated to 265.7% of the control by disopyramide and to 184.4% by MIP, with half-effective concentrations (EC50) of 30.9 +/- 1.5 microM and 92.4 +/- 2.2 microM. We tested the possibility that these drugs induce insulin release by inhibiting ATP-sensitive K+ (K(ATP)) channels of MIN6 cells. In the cell-attached or ATP-free inside-out mode with patch membranes on MIN6 cells, K-selective channels were recorded with unitary conductance of 70.5 +/- 3.5 pS (150 mM external K+ ions at room temperature). The channels were concluded to be MIN6-K(ATP) channels because they were closed by extracellular high glucose (11.0 mM) or glibenclamide (200 nM) and were reversibly activated by diazoxide (50 microM). In the inside-out patch mode, they were inhibited by micromolar ATP. In both cell-attached and insideout mode, disopyramide and MIP inhibited single MIN6-K(ATP) channels. In the inside-out mode, they produced a dose-dependent inhibition of channel activity: the half-blocking concentrations (IC50) were 4.8 +/- 0.2 microM for disopyramide and 40.4 +/- 3.1 microM for MIP. It was therefore concluded that both agents exert insulinotrphic effect through the inhibition of membrane K(ATP) channels in MIN6 cells.

Overexpression of Cas-interacting zinc finger protein (CIZ) suppresses proliferation and enhances expression of type I collagen gene in osteoblast-like MC3T3E1 cells

Osteoblasts are the cells which form bone under the regulation not only by hormones and cytokines but also by ECM molecules via their attachment. To obtain insights into the role of intracellular signaling molecules operating to mediate the attachment-related regulation of osteoblastic functions, we investigated in osteoblast-like MC3T3E1 cells the effects of the overexpression of CIZ, a novel signaling protein which interacts with p130Cas. In MC3T3E1 cells, CIZ mRNA is expressed constitutively. Endogenous CIZ was localized in the MC3T3E1 cells with relatively high levels of accumulation at the attachment sites when the cells were cultured on fibronectin, collagen, or BSA. CIZ overexpression increased the number of adhesion plaques and reduced proliferation of the cells compared to that of control cells transfected with an empty vector. Furthermore, CIZ overexpression enhanced type I collagen mRNA expression, the most abundant constituent of bone matrix and a major product of osteoblasts. Analysis of the promoter region of type I collagen gene identified the presence of a consensus CIZ-binding sequence, which indeed conferred responsiveness to CIZ overexpression to a heterologous promoter. These data indicate that CIZ acts as a novel regulatory molecule in controlling osteoblastic function.

Sequence analyses of CYP2B genes and catalytic profiles for P450s in Qdj:Sprague-dawley rats that lack response to the phenobarbital-mediated induction of CYP2B2

The Qdj:Sprague-Dawley (SD) rat is a mutant strain lacking in phenobarbital (PB)-mediated induction of CYP2B2. The presence of interindividual differences in the hepatic content of CYP2B proteins and testosterone 16beta-hydroxylase activity demonstrated that the breeding colony of Qdj:SD rats involves normal (+/+) and intermediate (+/-) phenotypes as well as mutant (-/-)-type rats. Although PB-treated Qdj:SD (-/-) rats expressed CYP2B1 normally, testosterone 16beta-hydroxylase activity in these rats was quite low. Analysis of regioselective metabolism of testosterone and 4-hydroxybiphenyl glucuronidation demonstrated normal catalytic activities associated with other forms of cytochrome P450s, including CYP2A, -2C, and -3A, as well as PB-inducible UDP-glucuronosyltransferase in Qdj:SD (-/-) rats. There were no serious mutations in the exons of the CYP2B1 gene in Qdj:SD (-/-) rats, demonstrating that this gene codes a functional CYP2B1. These observations suggest that CYP2B1 needs the interaction with CYP2B2 to exert the full function. The CYP2B2 gene in Qdj:SD (-/-) rats was the same as that in wild-type (+/+) rats in its length of the region containing all exon/introns and 5'-upstream up to -2.3 kilobase pairs. Malignant mutation such as stop codon formation was not observed in the exons, and no mutation was detected in the region containing the PB-responsive unit. These results strongly suggest that impaired induction of CYP2B2 in Qdj:SD (-/-) rats is attributable either to mutation at the region different from PB-responsive unit and exons or to absence or lowered expression of trans-acting factor(s) necessary for gene regulation.

Cytokine requirement for the development of T-lymphoid lineage potential in clonal lymphohaematopoietic progenitors in vitro

The early process of T-cell development prior to thymic colonization has been poorly investigated because of the lack of a sensitive assay. We have developed a two-step in vitro culture system by combining a clonal culture with a fetal thymus organ culture (FTOC) and analysed the early development of T cells from lymphohaematopoietic progenitors. Cells of immature colonies derived from bone marrow cells of 5-fluorouracil (5FU)-treated mice using various combinations of early acting cytokines were transferred into a FTOC. All the combinations of stem cell factor (SCF), interleukin (IL)-3 and IL-6 capable of inducing colony formation supported T-cell generation. IL-11 and the Flt3 ligand possessed T-lineage promotional effects similar to IL-6 and SCF respectively. However, there were some quantitative differences in the final T-cell yield among cytokine combinations. Thus, the commitment towards T lineage in lymphohaematopoietic progenitors may be an event determined intrinsically rather than induced by specific stimuli, but there may be a hierarchy between the activity of cytokines in further development. Furthermore, we examined the T-lineage potential of individual colonies derived from Lin(-)c-Kit(+)Sca-1(+) cells clone-sorted from post-5FU marrow cells. No colonies that contained only myelocytic progenitors showed T-lineage potential, but 23.3% of colonies with a haematopoietic multipotentiality did. Therefore, the divergence of the T lineage from other lineages such as myeloid potential may occur at an early stage of the hierarchy of haematopoiesis. The proposed method should prove valuable for exploring the molecular and cellular changes that occur during early T-cell development before thymic colonization.

Peroxisome proliferator-activated receptors are expressed in human cultured mast cells: a possible role of these receptors in negative regulation of mast cell activation

We investigated the expression of peroxisome proliferator-activated receptors (PPAR) in human cultured mast cells (HCMC) by using the reverse transcription-polymerase chain reaction. HCMC expressed mRNA of PPARbeta, gamma1, and gamma2 constitutively, whereas PPARalpha was not detected. Though PPARgamma2 was expressed weakly, activation of HCMC with anti-IgE after IgE sensitization or with calcium ionophore plus phorbol ester resulted in increased expression of PPARgamma2 specifically. These stimuli did not influence the expression of PPARalpha and beta. In addition, provocation of HCMC with IgE or with IL-4 increased the mRNA level of PPARgamma2, and a synergistic effect was observed with the combination of IgE plus IL-4. To investigate a possible role of PPAR in mast cells, we examined the effects of PPAR agonists on cytokine production by HCMC. Prostaglandin (PG) D(2), Delta(12)-PGJ(2), 15deoxy-Delta(12, 14)-PGJ(2) (15d-PGJ(2)), and troglitazone, all of which are PPARgamma agonists, attenuated the production of granulocyte-macrophage colony-stimulating factor by anti-IgE-stimulated HCMC. A similar effect was observed with carbaprostacyclin, a PPARbeta agonist, but not with PPARalpha agonists. Anti-IgE-induced expression of cytokine mRNA, such as TNF-alpha, IL-5 and macrophage inflammatory protein-1alpha mRNA, was also reduced by the treatment with these PPARgamma agonists. Though only Delta(12)-PGJ(2) and 15d-PGJ(2) revealed an inhibitory effect on histamine release, leukotriene C(4) release from HCMC was suppressed by all tested PPARgamma agonists. These results indicate that HCMC express PPARbeta and gamma1/2, which might negatively regulate the activation of HCMC.

Natural killer cell depletion by anti-asialo GM1 antiserum treatment enhances human hematopoietic stem cell engraftment in NOD/Shi-scid mice

The scid mutation was backcrossed on to the NOD/Shi mouse background, resulting in the development of NOD/Shi-scid mice, which showed lack of mature lymphocytes, macrophage dysfunction and absence of circulating complement, but were not as impaired in natural killer (NK) cell activity as NOD/LtSz-scid mice. We then examined the effect of recipient NK cell depletion by anti-asialo GM1 antiserum on the repopulation of human cord blood (CB) hematopoietic stem cells (HSC) in NOD/Shi-scid mice to clarify the role of recipient NK cells in human HSC engraftment. The anti-asialo GM1 antiserum treatment significantly enhanced the engraftment of CB CD34+ cells, but did not affect the differentiation of the engrafted HSC into each hematopoietic lineage. The NK cell depletion was effective at early stages of the engraftment, but not 3 weeks after the transplantation. The anti-asialo GM1 antiserum treatment did not improve the engraftment by human HSC in scid mice which lack mature lymphocytes, but show neither macrophage dysfunction nor a reduction in circulating complement, indicating that macrophages and/or complement also have roles in HSC graft rejection. The present study indicates that the preconditioning targeting of recipient NK cells in addition to T cell suppression and myeloablation might prevent HSC graft failure, and that NOD/Shi-scid mice treated with anti-asialo GM1 antiserum could provide a useful tool for evaluating the repopulating ability of transplantable human HSC.

Glycoprotein 130 and c-kit signals synergistically induce thrombopoietin production by hematopoietic cells

We have reported that simultaneous activation of glycoprotein (gp) 130 and c-kit signals by interleukin (IL)-6, soluble IL-6 receptor (sIL-6R), and stem cell factor (SCF) promotes proliferation of human hematopoietic progenitor cells and their differentiation into erythroid, myelocytic, and megakaryocytic cells. We recently found that erythropoietin produced by erythroid progenitors stimulates erythropoiesis via gp130 and c-kit signals. Here we examined thrombopoietin (TPO) production by hematopoietic cells cultured with IL-6, sIL-6R, and SCF. Reverse transcription-polymerase chain reaction analysis indicated that hematopoietic cells generated from cord blood CD34+ cells with the 3 factors expressed a minor splice variant of TPO messenger RNA, P1 delta E2, which can be translated to TPO protein more efficiently than regularly spliced isoforms. The reduction in c-mpl, receptors for TPO, by antisense oligodeoxynucleotides suppressed the generation of erythroid, myelocytic, and pluripotent progenitors in suspension culture, plus colony formation of megakaryocytic progenitors in addition to these progenitors in clonal culture of cord blood CD34+ cells with IL-6, sIL-6R, and SCF. The addition of anti-human TPO antibody to the clonal culture also suppressed colony formation. These findings indicate that TPO production by hematopoietic cells stimulated by IL-6, sIL-6R, and SCF is involved in promoting their own growth.

Garlic and onion oils inhibit proliferation and induce differentiation of HL-60 cells

Phytochemicals present in the genus Allium have potential pharmacological effects, such as antimicrobial, antithrombotic, antitumor, hypolipidaemic and hypoglycemic activities. In this present study, we examined the effects of garlic and onion oils on human promyelocytic leukemia cells, HL-60. Incubation of HL-60 with garlic or onion oil (20 microg/ml) caused a marked suppression of HL-60 proliferation; the suppression was almost identical with those obtained by all-trans-retinoic acid (ATRA) or dimethyl sulfoxide (DMSO) used as positive controls. These oils induced the generation of nitroblue tetrazolium (NBT)-reducing activity, and about 20% of the HL-60 cells became NBT positive. CD11b, another marker of the differentiation of these cells, was also significantly induced by garlic oil or onion oil. The combination of garlic or onion oil with ATRA was more effective than either alone. These data suggest that garlic and onion oils have the ability to induce differentiation of HL-60 cells into those of the granulocytic lineage.

Augmentation of basal insulin release from rat islets by preexposure to a high concentration of glucose

We have found that preexposure to an elevated concentration of glucose reversibly induces an enhancement of basal insulin release from rat pancreatic islets dependent on glucose metabolism. This basal insulin release augmented by priming was not suppressed by reduction of the intracellular ATP or Ca(2+) concentration, because even in the absence of ATP at low Ca(2+), the augmentation was not abolished from primed electrically permeabilized islets. Moreover, it was not inhibited by an alpha-adrenergic antagonist, clonidine. A threshold level of GTP is required to induce these effects, because together with adenine, mycophenolic acid, a cytosolic GTP synthesis inhibitor, completely abolished the enhancement of basal insulin release due to the glucose-induced priming without affecting the glucose-induced increment in ATP content and ATP-to-ADP ratio. In addition, a GDP analog significantly suppressed the enhanced insulin release due to priming from permeabilized islets in the absence of ATP at low Ca(2+), suggesting that the GTP-sensitive site may play a role in the augmentation of basal insulin release due to the glucose-induced priming effect.

Improvement in bronchiolitis obliterans organizing pneumonia in a child after allogeneic bone marrow transplantation by a combination of oral prednisolone and low dose erythromycin

We report a 13-year-old boy who developed dyspnea at rest 1 year after the occurrence of cGVHD following an allogeneic bone marrow transplant (BMT). Pulmonary function data, imaging studies, lung biopsy, and bronchoalveolar lavage were consistent with the diagnosis of bronchiolitis obliterans organizing pneumonia (BOOP). Although reports suggest that oral methylprednisolone or methylprednisolone pulse therapies improve BOOP after BMT, we treated our patient with a combination of oral prednisolone (1 mg/kg) and low dose erythromycin (10 mg/kg) to avoid the side-effects of high-dose steroids. With this therapy, our patient showed clinical and radiological improvements within 1 week. The steroids were tapered off 12 months later and erythromycin was given for 14 months. We conclude that therapy consisting of a combination of oral prednisolone and low-dose erythromycin for BOOP after BMT may minimize the dose and duration of steroid use.

Rapid screening method to detect mutations in CYP21, the gene for 21-hydroxylase

To facilitate a rapid and practical molecular diagnosis of 21-hydroxylase deficiency (21-OHD), we developed a polymerase chain reaction (PCR) test in which only the 21-OH gene (CYP21) is amplified. We applied the test to diagnose 23 patients with salt-wasting type of 21-OHD. The upstream and downstream sequences of CYP21 have been specifically amplified by using a primer set containing the 8-bp deletion sequence of exon 3, which is distinct from its pseudogene CYP21P. The amplified PCR products were further subjected to mutation detection by restriction analysis: E1PL by AciI, I2g by PstI, E63a by DraIII, E7VL by ApaLI, E8non by PstI, and E8RW by AciI. To detect delections and/or gene conversions occurring on exon 3, we used the method described by Rumsby and Honour [1990: J Med Genet 27:676-678]. Our method is able to elucidate 8 common CYP21 mutations by using only 3 primer pairs and 4 restriction enzymes. The overall detection ratio of abnormal haplotypes by this method was over 95%, indicating that our method is practical and useful, particularly for carrier detection.

The properties of the Kir6.1-6.2 tandem channel co-expressed with SUR2A

Functional ATP-sensitive K (KATP) channels have an octameric subunit structure with four pore-forming subunits (Kir6.x) and four sulfonylurea receptors (SURx). In the present study, the properties of the heteromeric KATP channel whose pore subunits are composed of Kir6.1 and Kir6.2 were examined using a heterologous expression system. In COS7 cells co-transfected with Kir6.1, Kir6.2 and SUR2A at a ratio of 1:1:2, KATP channels showed various unitary conductances between those of Kir6.1/SUR2A (33.6+/-4.2 pS) and Kir6.2/ SUR2A (67.1+/-1.6 pS). Kir6.1-6.2 tandem protein, constructed by fusing the C-terminus of Kir6.1 to the N-terminus of Kir6.2 with a ten glutamine linker sequence, also formed a channel with an intermediate conductance (58.9+/-1.5 pS). Kir6.2 and Kir6.1-6.2 showed similar sensitivity to ATP4-: half-maximal inhibition (IC50) was obtained at 14.1+/-12.8 microM and 17.6+/-9.6 microM, respectively. In the presence of Mg2+, Kir6. 1-6.2 was significantly less sensitive than Kir6.2 to MgATP (IC50=95.5+/-49.6 microM versus 18.9+/-5.0 microM). These results suggest that Kir6.1 and Kir6.2 are endowed with the potential to form a heteromeric KATP channel, which has a low sensitivity to MgATP.

Anti-AB titer changes in patients with ABO incompatibility after living related kidney transplantations: survey of 101 cases to determine whether splenectomies are necessary for successful transplantation

BACKGROUND

A shortage of organ donors for transplantation has become a serious problem throughout the world. To overcome this problem, transplantations across ABO blood barriers have been performed with some success. In general, however, the graft survival rate for transplantation with ABO incompatibility is lower than that of transplantation with ABO compatibility. Unfortunately, the mechanism by which isohemagglutinins might injure an ABO-incompatible graft remains uncertain. Here, the pre- and posttransplantation anti-AB titers in patients who received transplants from ABO-incompatible living donors are reviewed and the pathological findings are compared.

METHODS

One hundred and one patients underwent ABO-incompatible living related kidney transplantation (i-LKT) between January 1989 and October 1999 at our hospital. Plasmapheresis and immunoadsorption were performed in all of the i-LKT patients before the transplantation to remove anti-AB antibodies. A splenectomy was also performed during the operation, followed by the local irradiation of the graft with a dose of 150 rad. The anti-AB titers and pathological findings for 93 i-LKT patients, excluding 8 patients who died, were then examined.

RESULTS

Immediately after the i-LKT, the anti-AB titer dropped rapidly to below 1:4 in all 93 cases. Seventy of patients (70/93, 75%) showed no elevation in their anti-AB titer during their follow-up. However, the remaining 23 patients (23/93, 25%) showed a significant elevation of their anti-AB titer to over 1:16. Sixteen of these patients (16/93, 17%) exhibited an anti-AB titer of over 1:32. Out of these 16 patients, 11 patients (11/16, 69%) lost their grafts. The anti-AB titer in the remaining five patients (5/16, 31%) spontaneously decreased without any special treatment. Seven patients (7/93, 8%) exhibited an elevated titer of 1:16. Out of these patients, only one patient (1/7, 14%) lost his graft. The elevated titers in the remaining six patients (6/7, 86%) eventually decreased. The graft function improved in patients whose elevated anti-AB titers eventually decreased. Control patients (ABO-compatible kidney transplant patients) showed a normal elevation of their titer values compared with preoperative titers. Pathological findings showed severe humoral rejections in all cases with high anti-AB titers that lost grafts. Humoral rejection was also detected in most of the patients whose anti-AB titer was elevated to over 1:16 after the transplantation, but excellent renal function was resumed once the titers decreased to below 1:4.

CONCLUSIONS

In 23 out of 93 i-LKT patients (25%), the anti-AB titers were significantly elevated after the splenectomy. In view of other reports of i-LKT without splenectomy, we feel that a splenectomy in i-LKT patients might be unnecessary. Pathological evidence suggests that the decrease in the anti-AB titer after transplantation might be the net result of plasmapheresis before the operation and the adsorption of antibodies to the endothelium of the transplanted organ after the operation, neither of which is influenced by a splenectomy.

Significance of lung resistance-related protein in the clinical outcome of acute leukaemic patients with reference to P-glycoprotein

Lung resistance-related protein (LRP) overexpression in leukaemic blast cells from acute leukaemia patients and the effect of LRP or P-glycoprotein (P-gp) on the clinical outcome of acute leukaemia were investigated individually by dividing patients into four groups. The complete remission rate of group I (LRP and P-gp both negative) was 81.7%, group II (only LRP positive) 87.5%, group III (only P-gp positive) 87.1% and group IV (LRP and P-gp both positive) 40.0%. There were no statistical differences between group I and groups II or III, but a significant difference was observed between groups I, II or III and group IV. Median overall survival in group IV was significantly shorter (4.6 months) than in groups I, II or III, although no significant differences were observed between group I and groups II or III (18.9, 20.5 and 31.8 months). There was a tendency for disease-free survival in group III to be longer than that in groups I, II or IV. The reasons for these findings are discussed. Our present results indicate that the co-existence of LRP and P-gp strongly influenced the effectiveness of induction chemotherapy and long-term prognosis, whereas the isolated presence of LRP or P-gp did not.

[Aggressive transformation and extramedullary tumor formation in IgA-lambda multiple myeloma]

A 52-year-old woman complained of lower back pain and gluteal pain in April 1997, and was found to have anemia, hypercalcemia and renal disorder. In September of the same year, she was diagnosed as having IgA-lambda myeloma (stage IIIA). VMMD-IFN therapy was started in November, 1997, and this resulted in improvement of the M-protein level, and relief of the pain in the lower back and gluteal region. A second course of VMMD-IFN therapy was also effective. In April 1998, however, the back pain worsened, and in July the patient suffered a fall and fractured her left femur. Upon readmission to our hospital, the level of M-protein was lower, and high fever, hypercalcemia, renal disorder, elevation of the LDH level, anemia and thrombocytopenia were observed. Bone marrow examination revealed 30% atypical large-sized CD19-, CD38+, CD56+ myeloma cells and chromosomal abnormalities. Although the symptoms were improved temporarily after a third course of VMMD therapy, disease aggravation occurred again, and extramedullary masses appeared on the head, face and pelvis. VAD therapy was performed without effect, and the patient died about 2 months after recurrence. This was a comparatively rare case of fulminant multiple myeloma occurring in the terminal stage.

Hematopoietic repopulating ability of cord blood CD34(+) cells in NOD/Shi-scid mice

Although umbilical cord blood (CB) is increasingly being used as an alternative to bone marrow (BM) as a source of transplantable hematopoietic stem cells (HSC), information on the hematopoietic repopulating ability of CB HSC is still limited. We recently established a xenotransplantation system in NOD/Shi-scid mice to evaluate human stem cell activity. In the present study, we transplanted 5 to 10 x 10(4) CB CD34(+) cells into six NOD/Shi-scid mice treated with anti-asialo GM1 antiserum to investigate the hematopoietic repopulating ability of CB. The BM of all recipients contained human CD45(+) cells 10 to 12 weeks after the transplantation (43.8 +/- 17.7%). Clonal culture of the recipient BM cells revealed the formation of various types of human hematopoietic colonies, including myelocytic, erythroid, megakaryocytic, and multilineage colonies, indicating that CB HSC can differentiate into hematopoietic progenitors of various lineages. However, the extent of the differentiation and maturation differed with each lineage. CD13(+)/CD14(+)/CD33(+) myelocytic cells were mainly repopulated in BM and peripheral blood (PB). While CD41(+) megakaryocytic cells and platelets were present, few glycophorin A(+)CD71(+) or hemoglobin alpha-containing erythroid cells were detected. CD19(+) B cells were the most abundantly repopulated in NOD/Shi-scid mice, but their maturational stage differed among the hematopoietic organs. Most of the BM CD19(+) cells were immature B cells expressing CD10 but not surface immunoglobulin (Ig) M, whereas more mature CD19(+)CD10(-) surface IgM(+) B cells were predominantly present in spleen and PB. CD3(+) T cells were not detected even in the recipient thymus. The transplantation to the NOD/Shi-scid mouse may provide a useful tool for evaluating the repopulating ability of transplantable human HSC.

Identification and expression of a novel 3'-exon of mouse Runx1/Pebp2alphaB/Cbfa2/AML1 gene

Cbfa1 (recently renamed as Runx2) is prerequisite for the differentiation of osteoblasts that play a central role in regulation of bone metabolism. Runx transcription factors belong to Drosophila pair rule gene "runt" family that also play critical roles during the development of hematopoietic tissues or insect bodies. To identify novel sequences related to Runx (Cbfa) genes, we screened a 11 d.p.c (days postcoitum) mouse embryonic cDNA library using a probe corresponding to Runx2 (Cbfa1) runt domain and identified a novel cDNA fragment. This cDNA (521-41) is about 2.4 kb in length and contains a sequence identical to the N-terminal half of mouse Runx1 (Pebp2alphaB/Cbfa2/AML1b) and a novel protein coding sequence in the C-terminal region. High expression levels of 521-41 mRNA were observed during the early mouse embryogenesis. In adult mice, 521-41 mRNA was expressed ubiquitously in lumbar vertebrae, brain, kidney, heart, muscle, and ovary. We also found that 521-41 mRNA was constitutively expressed in an osteoblast-like cell line, MC3T3E1. These data indicate that 521-41 gene is a novel splicing variant of mouse Runx1 which is expressed in skeletal tissues and osteoblast-like cells.

New induction of leukotriene A(4) hydrolase by interleukin-4 and interleukin-13 in human polymorphonuclear leukocytes

Interleukin (IL)-4, IL-10, and IL-13, Th2 cell-derived cytokines, play major roles in the pathophysiology of allergic diseases. These cytokines up-regulate or down-regulate the production of arachidonic acid metabolites. In this study, we have investigated the effect of IL-4, IL-10, IL-13, and other cytokines on A23187-stimulated synthesis of leukotriene (LT) B(4) in human polymorphonuclear leukocytes (PMNs). Production of LTB(4) was measured by specific radioimmunoassay and high performance liquid chromatography. Messenger RNA (mRNA) expression of cytosolic phospholipase A(2) (cPLA(2)), 5-lipoxygenase (5-LO), and LTA(4) hydrolase, which were involved in the synthesis of LTB(4), was determined by reverse transcription-polymerase chain reaction and Northern blot analysis. Protein synthesis of their enzymes was determined by Western blot analysis. IL-4 and IL-13 enhanced A23187-stimulated LTB(4) synthesis and increased mRNA expression and protein synthesis of LTA(4) hydrolase, but not those of cPLA(2) or 5-LO. These results indicate that IL-4 and IL-13 transcriptionally or post-transcriptionally up-regulate the synthesis of LTB(4), a potent chemotactic factor to PMNs, at the enzyme level of LTA(4) hydrolase, and this up-regulation mechanism may participate in the development of allergic inflammation. (Blood. 2000;96:601-609)

Erythroid progenitors differentiate and mature in response to endogenous erythropoietin

We reported previously that stimulation of glycoprotein 130 (gp130) by a combination of human IL-6 and soluble IL-6 receptor (sIL-6R) could support proliferation, differentiation, and terminal maturation of erythroid cells in the absence of erythropoietin (EPO) from human CD34(+) cells in culture with stem cell factor (SCF). This observation suggested that differentiation of hematopoietic stem/progenitor cells to erythroid cells progressed according to an intrinsic program and that EPO receptor (EPOR) could be replaced by other cytokine receptors. In other words, EPOR appeared to be dispensable for erythropoiesis. Here we examined the role of EPOR in erythropoiesis stimulated by SCF, sIL-6R, and IL-6. Surprisingly, reduction of EPOR expression using antisense oligodeoxynucleotides suppressed erythropoiesis stimulated not only by SCF and EPO, but also by SCF, sIL-6R, and IL-6. EPO mRNA was detected in erythroid cells but not myeloid cells cultured in the presence of SCF, sIL-6R, and IL-6. Furthermore, high concentrations of anti-EPO-neutralizing antibody abrogated erythropoiesis in cultures without exogenous EPO. Based on these results, we suggest that erythroid progenitors themselves secrete EPO and that they have the potential to differentiate and mature in response to this endogenous EPO.

(9-[4-acetyl-3-hydroxy-2-n-propylphenoxy) methyl]-3-(1H-tetrazol-5-yl)-4H-pyrido [1,2-a] pyrimidin-4-one), AS-35, inhibits leukotriene synthesis

AS-35, (9-[4-acetyl-3-hydroxy-2-n-propylphenoxy) methyl]-3-(1H-tetrazol-5-yl)-4H-pyrido[1, 2-a] pyrimidin-4-one), was developed as a leukotriene (LT) receptor antagonist, which also inhibited IgE-mediated release of leukotrienes (LTs). We have investigated the action of AS-35 on the enzyme activities which are involved in the synthesis of LTC(4) and LTB(4) (LT-synthesizing enzymes); cytosolic phospholipase A(2) (cPLA(2)), 5-lipoxygenase (5-LO), leukotriene (LT)C(4) synthase and LTA(4) hydrolase. AS-35 dose-dependently inhibited IgE- and A23187-stimulated production of LTC(4) by up to 71.5-84.8% and that of LTB(4) by 48.3-49.2% at 2. 5x10(-5) M. The assays for cPLA(2)(-), 5-LO-, LTC(4) synthase- and LTA(4) hydrolase-activities revealed that the inhibition is attributable to suppression of cPLA(2), 5-LO and LTC(4) synthase but not LTA(4) hydrolase. We have also studied the action of AS-35 on the release of beta-hexosaminidase (beta-HEX) as a marker of preformed mediators. AS-35 had only weak inhibitory action on the release of beta-HEX. The results indicate that anti-allergic action of AS-35 is predominantly attributable to its inhibition of LT synthesis by suppressing three consecutive enzymes for LTC(4) synthesis.

No association of borna disease virus with psychiatric disorders among patients in northern Kyushu, Japan

There is controversy over the prevalence of Borna disease virus (BDV) antibodies and its RNA in the peripheral blood mononuclear cells (PBMCs) of psychiatric patients, and the contribution of BDV to human psychiatric disorders. We examined 299 plasma and 229 PBMC samples. No plasma samples were positive for BDV-p40, p24 or gp18 antibodies by western blot analysis. The prevalence of BDV RNA in the psychiatric (schizophrenic) patients (1.8%) was not significantly different from that in the healthy volunteers (0.6%). The nucleotide sequences of BDV p40 and p24 were highly conserved with those of BDV He/80. Our results suggested that there is a lack of association between BDV infection and psychiatric disorders among the patients in Northern Kyushu, Japan.

New method for determining total dietary fiber by liquid chromatography

The molecular weight limit of water-soluble dietary fiber (SDF) determined by the Prosky method was studied by liquid chromatography (LC). It was confirmed that only SDF with an average degree of polymerization of 12 or higher can be determined by the Prosky method. Total dietary fiber (TDF) was determined by 2 additional methods using LC. In the first method, the total quantity of insoluble dietary fiber (IDF) and high molecular weight SDF (HMSDF) was determined according to the modified Prosky method (MES-TRIS buffer-based). The quantitatively collected final filtrate was analyzed by LC for the quantity of low molecular weight SDF (LMSDF), and the 2 quantities were totaled to obtain TDF. TDF values thus determined for rice, polished or unpolished, soybean flour, and pressed barley were higher than those determined by the Prosky method by approximately 6, 3.5, and 3.5%, respectively. In the second method, direct determination by LC analysis was done on samples after enzymatic treatment according to the Prosky method. Results showed that the determination of LMSDF, in particular, was highly accurate and more effective. In both of these methods, the quantity of LMSDF was determined from its chromatographic peak area ratio to glucose as an internal standard, which was produced by hydrolysis.

Protection of breathing zone by uniform velocity blowing

A system of work site ventilation that blows clean air around a worker's nose and mouth was studied. The characteristics of the blowing flow were examined experimentally and then for a practical application. Field tests were performed to confirm the effectiveness of the blowing equipment during concrete chipping at a building construction site. This type of ventilation was found to be useful for contaminants with relatively low toxicity (e.g., nuisance dust); however, the technique may increase the exposure of workers in adjacent areas, since the dust is not captured or filtered. It became evident that the worker's dust exposure during the chipping could be decreased by using the air-blowing equipment.

An osteogenesis-related transcription factor, core-binding factor A1, is constitutively expressed in the chondrocytic cell line TC6, and its expression is upregulated by bone morphogenetic protein-2

Core-binding factor A1 (Cbfa1), also called Pebp2 alpha A/AML3, is a transcription factor that belongs to the runt-domain gene family. Cbfa1-deficient mice are completely incapable of both endochondral and intramembranous bone formation, indicating that Cbfa1 is indispensable for osteogenesis. Maturation of chondrocytes in these mice is also disorganized, suggesting that Cbfa1 may also play a role in chondrogenesis. The aim of this study was to examine the expression and regulation of Pebp2 alpha A/AML3/Cbfa1 expression in the chondrocyte-like cell line, TC6. Northern blot analysis indicated that Cbfa1 mRNA was constitutively expressed as a 6.3 kb message in TC6 cells and the level of Cbfa1 expression was enhanced by treatment with bone morphogenetic protein-2 (BMP2) in a time- and dose-dependent manner. This effect was blocked by an RNA polymerase inhibitor, 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole, but not by a protein synthesis inhibitor, cycloheximide. Western blot analysis of the cell lysates using polyclonal antibody raised against Cbfa1 indicated that BMP2 treatment increased the Cbfa1 protein level in TC6 cells. In TC6 cells, BMP2 treatment enhanced expression of alkaline phosphatase and type I collagen mRNAs but suppressed that of type II collagen mRNA. In addition to TC6 cells, Cbfa1 mRNA was also expressed in primary cultures of chondrocytes and BMP2 treatment enhanced Cbfa1 mRNA expression in these cells similarly to its effect on TC6 cells. These data indicate that the Pebp2 alpha A/AML3/Cbfa1 gene is expressed in a chondrocyte-like cell line, TC6, and its expression is enhanced by treatment with BMP.

RT-PCR detection of breast cancer cells in sentinel lymph modes

Sentinel lymph node (SLN) biopsy is being evaluated in breast cancer patients to improve detection of metastases and to guide therapy with minimal morbidity. The aim of this study was to increase the sensitivity of tumor cell detection in SLNs using superior reverse transcription polymerase chain reaction (RT-PCR) for carcinoembryonic antigen (CEA) and mammaglobin (MMG) analysis rather than current methods which fail to identify clinically relevant disease in many patients. In seventy stage I and II breast cancer patients dye-guided lymph node mapping was performed and the SLNs were divided alternately for RT-PCR or hematoxylin and eosin staining (H&E). RT-PCR and H&E diagnosis of SLNs were compared. SLNs were identified in 66/70 (94.3%) patients. Seventeen patients (26. 2%) had histological metastasis in SLNs. CEA was expressed in 25.0% of 48 patients with H&E negative SLNs, and MMG was expressed in 20. 8%. SLNs could predict axillary lymph node status with 95.4% accuracy and 6.3% false negative rate by H&E. Moreover, RT-PCR improved these to 98.5% and 2.8%, respectively. SLN diagnosis using RT-PCR is a powerful and sensitive method, which increases the accuracy of clinical staging and may provide more informed choices for appropriate therapeutic management of breast cancer patients.

Immunoaffinity purification method for detection and quantification of microcystins in lake water

We have developed a new clean-up method, which consisted of solid-phase extraction on a Sep-Pak PS-2 (styrene-divinylbenzene copolymer) or Excelpak SPE-GLF (polymethacrylate) cartridge instead of conventional ODS silica gel and silica gel together with following immunoaffinity purification using anti-microcystin-LR monoclonal antibodies. This newly developed method was demonstrated to eliminate co-existing substances and to concentrate microcystins in the lake water. The recoveries from lake water (1 liter) spiked with 100 ng each of microcystins-RR, -YR and -LR were 85.5, 89.2 and 92.2%, respectively, with coefficients of variation of 3.3-7.6%. Only 3 h were required to complete the total procedures starting from the microcystin extraction, the immunoaffinity purification, and the quantification using HPLC. The detection limits for all of the 3 microcystins in lake water were 0.005 microg/l. Applicability of this method has been demonstrated by measuring the concentrations of microcystins in water samples collected from lakes where water blooms occurred, which turned out to be 0.012-0.177 microg/l of total microcystins.

Massive pericardial and pleural effusion with anasarca following allogeneic bone marrow transplantation

A 10-year-old girl presented with massive pericardial/pleural effusion with anasarca 216 days after an allogeneic bone marrow transplantation from her HLA-matched sibling for relapsed acute lymphoblastic leukemia. She did not show any other symptoms of chronic graft-versus-host disease (GVHD). The antinucleolar antibody was elevated in the blood and the pleural fluid. The lymphocytes in the fluid were mostly CD8+/HLA-DR+, and a majority of CD8+ cells in the blood expressed CD57. These data suggested that she had chronic GVHD. Immunosuppressive therapy including prednisolone, cyclosporin A, high-dose methylprednisolone, tacrolimus (FK506), and methotrexate had no effect, and the patient died of Aspergillus pneumonia 183 days after the presentation of the disease. Although it has not been described before, isolated serositis with edema should be recognized as a clinical feature of chronic GVHD.

[A surgical case of adult Bochdalek hernia assisted by thoracoscopic surgery]

A case of adult Bochdalek hernia in a naturally healthy 49-year-old woman is described. She was seen at our hospital because of cough lasting for about one month. The chest X-ray film revealed a gastrointestinal gas image in the left thoracic cavity. In addition, the CT scan and upper gastrointestinal series showed prolapse of the stomach, small intestine and a part of transverse colon. Operation was performed through a mini-thoracotomy using a thoracoscope assistedly. No hernia sac was observed and the diaphragmatic defect was 6 x 5 cm in size. After the organs was restored, the defect was closed with continuous over-and-over suture and the diaphragm was enhanced by PROLEN MESH.

Recording of mechano-electrical transduction currents by a nystatin perforated-patch method

Mechano-electrical transduction (MET) currents in isolated cochlear hair cells of chicks were recorded by use of a nystatin perforated-patch method. The membrane of a cell-attached patch was permeabilized by nystatin in the patch pipette, thus providing electrical continuity between the pipette and the cytoplasm of the cell without loss of cytoplasmic compounds. The current-voltage relationship was linear for the inward-going MET current at negative membrane potentials, but outward currents were reduced at positive membrane potentials, evidence of inward-going rectification. Elevation of the intracellular concentration of calcium at positive membrane potential, mediated via a voltage-dependent Ca2+ channel, may suppress the outward-going MET current by acting from within the cell.