Cooperative function of the CHD5-like protein Mdm39p with a P-type ATPase Spf1p in the maintenance of ER homeostasis in Saccharomyces cerevisiae

Spf1p is a P-type ATPase that is mainly localized to the endoplasmic reticulum (ER) in Saccharomyces cerevisiae. The protein is involved in the maintenance of ion homeostasis in the ER. To investigate the intracellular role of Spf1p in more detail, we performed a genetic screen for mutations that lead to synthetic lethality in combination with a disruption of SPF1; the mutations identified have been termed lws (for lethal with spf1) mutations. Mutant alleles of five LWS genes (MDM39, RIC1, LAS21, TUP1 and BTS1) were recovered. The identification of these genes provides clues to the physiological relationships between Spf1p function and the secretory pathway. Among the five genes identified, MDM39 encodes a membrane protein that is similar to the protein CHD5/WRB, which is involved in the pathogenesis of Down syndrome-associated congenital heart disease in humans. We localized Mdm39p to the ER. The Deltamdm39 mutant exhibited defects in glycosylation, cell wall organization and the unfolded protein response. It also showed calcium-related phenotypes and synthetic lethal interactions with deletion mutations in other LWS genes. Our findings imply a homeostatic role for Mdm39p, which may be related to the regulation of calcium ion fluxes in the ER, and is indispensable for mutants that lack Spf1p.

Elevated IgG4 concentrations in serum of patients with Mikulicz's disease

Mikulicz's disease has recently been included within primary Sjögren's syndrome. It is a unique condition involving enlargement of the lacrimal and salivary glands, characterized by few autoimmune reactions. It is responsive to glucocorticoid treatment. Analysis of IgG fractions was performed in patients with Mikulicz's disease in order to determine the differences between Mikulicz's disease and Sjögren's syndrome. The study showed that serum IgG4 concentrations are elevated in patients with Mikulicz's disease, but not in those with Sjögren's syndrome.

A monoclonal antibody that recognizes Epstein-Barr virus nuclear antigen 2 (EBNA 2) amino acids 1-58 does not react with EBNA 2 in native form, consistent with the self-association of EBNA 2 through the amino-terminus

We have generated a mouse IgG1 monoclonal antibody (mAb) that recognizes amino acids 1-58 of Epstein-Barr virus (EBV) nuclear antigen 2 (EBNA 2) of type 1 EBV strain B95-8. mAb Y101 also reacted with EBNA 2 of EBV type 2 strains MISP and Jijoye in immunoblots, whereas Jijoye EBNA 2 was not detected by the widely used mAb PE2. mAb Y101, in contrast to mAb PE2, reacted with faster migrated, hypophosphorylated proteins of type 1 EBNA 2 as intensely as slower migrated, hyperphosphorylated ones. mAb Y101 did not react in fixed-cell immunostaining or cell extract immunoprecipitation. The results implicate that the amino-terminal epitope is not exposed in a native form, consistent with the previously reported idea of self-association of EBNA 2 through the amino-terminus. mAb Y101 is the first mAb to the EBNA 2 amino-terminus and will be useful for further analyses of the structure and function of EBNA 2.

Improved expression of novel red- and green-emitting luciferases of Phrixothrix railroad worms in mammalian cells

Luciferases are widely used for the quantitative monitoring of gene expression in a variety of organisms. We successfully expressed novel red- and green-emitting luciferases of Phrixothrix railroad worms in mammalian cells in combination with the Kozak sequence and the CAG promoter. The characteristic properties of these luciferases indicate that they are appropriate reporter genes for the simultaneous monitoring of two gene expressions.

The structure-activity relationship of various YO compounds, novel plasmin inhibitors, in the apoptosis induction

We have previously reported that YO-2, a selective plasmin inhibitor, induces thymocyte apoptosis. To elucidate the mechanism of YO-2-induced apoptosis, other YO compounds with different plasmin inhibitory action were tested for the pro-apoptotic activity in this study. The treatment of rat thymocytes with the YO compounds which had the hydrophobic but not the hydrophilic moiety at the C-terminal increased DNA fragmentation, the number of condensed nuclei and caspase-3-like activity. All pro-apoptotic YO compounds not only were potent plasmin inhibitors but also had the hydrophobic C-terminal as the common structure. Therefore, the target molecule of the YO compounds may be located not on the cell surface but rather inside the cells.

260 REPLACEMENT OF PVA WITH FETAL BOVINE SERUM IMPROVES FORMATION AND HATCHING OF PORCINE BLASTOCYSTS PRODUCED IN VITRO

Porcine embryos, derived from in vitro maturation and fertilization, were used to investigate the effects of timing of serum inclusion and PVA replacement in the medium for in vitro culture (IVC) on rates of blastocyst formation and hatching. In Experiment 1, presumptive zygotes at 20 h post-insemination (hpi) or cleaved embryos obtained by culture in porcine zygote medium (PZM-5) containing 3 mg mL−1 polyvinyl alcohol (PVA) at 48 or 96 hpi were further cultured in either PZM-5 containing PVA or PZM-5 where PVA was replaced by 1%, 5%, or 10% fetal bovine serum (FBS) until Day 6 (Day 0 = the day of in vitro insemination). Supplementation with 1% to 10% FBS at 20 and 48 hpi reduced (P < 0.05; by ANOVA and Fisher's PLSD test) blastocyst rates on Days 5 (0% to 1%) and 6 (3% to 6%) compared with PVA supplementation (4% and 22%, respectively). However, addition of 10% FBS at 96 hpi increased (P < 0.05) blastocyst rates (30%) on Day 5 compared with PVA (11%) and 1% FBS (15%); there was no significant difference among treatments in rates of blastocyst formation on Day 6 (24% to 40%). The total number of blastomeres in Day 6 blastocysts did not differ among treatments at any timing of serum supplementation (26.5 to 48.3 cells). In Experiment 2, presumptive zygotes were cultured from 20 to 96 hpi in PVA medium, and the cleaved embryos were later transferred into PZM-5 containing PVA, or 1%, 5%, or 10% FBS for another 4 days. Hatching rates of embryos on Days 7 and 8 were significantly higher (P < 0.05) in PZM-5 where PVA was replaced with 10% FBS (15% and 20%, respectively) than those in PZM-5 containing PVA (1% and 5%, respectively). Moreover, the total cell number in hatching/hatched blastocysts on Day 8 were significantly greater (P < 0.05) in medium containing 10% FBS (135.1 cells) than that in PVA medium (77.0 cells). In Experiment 3, at 130 hpi, blastocysts derived from IVC with PZM-5 containing PVA were transferred into PZM-5 containing PVA, 3 mg mL−1 bovine serum albumin (BSA) or 10% FBS for another 2 days. Hatching rates of blastocysts on Days 6, 7 and 8 were significantly higher (P < 0.05) in PZM-5 where PVA was replaced with 10% FBS (12%, 56%, and 64%, respectively) than those in PZM-5 containing PVA (0%, 12%, and 20%, respectively) and BSA (0%, 12%, and 20%, respectively). Moreover, the total cell number in hatching/hatched blastocysts on Day 8 were significantly greater (P < 0.05) in medium containing 10% FBS (138.7 cells) than that in PVA (71.7 cells) and BSA medium (70.7 cells). The results indicate that the timing of serum inclusion in the culture medium markedly affects porcine embryo development in vitro and that replacement of PVA with FBS in PZM-5 at 96 hpi or later improves the subsequent development of embryos to the hatching/hatched blastocyst stage. This work was supported by MAFF, Japan, and STINT and FORMAS, Sweden.

257 EFFECTS OF GLUTAMINE AND HYPOTAURINE ON OXIDATIVE STRESS OF PORCINE EMBRYOS CULTURED IN VITRO

We previously developed an in vitro production system for porcine embryos and reported that the addition of glutamine and hypotaurine during in vitro culture improved blastocyst yield and the total number of cells in the blastocysts. Glutamine and hypotaurine might reduce oxidative stress, allowing the development of embryos cultured in vitro, because glutamine reportedly protects embryos against oxidative stress by helping to maintain intracellular levels of cysteine, a precursor of glutathione (GSH), and hypotaurine is a potent antioxidant. In the present study we evaluated the effects of the presence of glutamine and hypotaurine from Day 2 (Day 0 = the day of in vitro fertilization) to Day 3 on oxidative stress during in vitro development of porcine embryos. Porcine cumulus-oocytes complexes from prepubertal gilts were matured and fertilized in vitro using frozen-thawed ejaculated boar semen (Yoshioka et al. 2003 Biol. Reprod. 69, 2092–2099). Presumptive zygotes were cultured in porcine zygote medium (PZM)-5 (Suzuki et al., 2002) containing 2 mM of glutamine and 5 mM of hypotaurine as a basal culture medium until Day 2. The cleaved embryos were then transferred into one of four media prepared as follows: (1) containing no glutamine or hypotaurine (G−H−), (2) containing glutamine (G+H−), (3) containing hypotaurine (G−H+), (4) containing glutamine and hypotaurine (G+H+) (= PZM-5), and cultured for 24 h. After culture, the total number of cells, intracellular GSH content, and level of hydrogen peroxide (H2O2), which is a reactive oxygen species, in the cleaved embryos were examined. Some cleaved embryos were cultured in PZM-5 from Day 3 until Day 5 and the percentage of embryos that developed into blastocysts and the total number of cells in the blastocysts were investigated. Intracellular GSH content and H2O2 level on Day 3 were determined by a dithionitrobenzoic acid-glutathione disulfide (DTNB-GSSG) reductase recycling assay and dichlorohydrofluorescein diacetate (DCHFDA)-based assay, respectively. Data were statistically analyzed by ANOVA and Fisher's PLSD test. The total number of cells (4.3 to 4.4 cells) and intracellular GSH content (2.3 to 2.9 pmol/embryo) in the cleaved embryos on Day 3 did not differ among treatments. On Day 3, the intracellular H2O2 level of the cleaved embryos cultured in G+H+ decreased by 49% compared with those cultured in G−H− (100%) (P < 0.05). On Day 5, the percentage of embryos that developed into blastocysts in G+H+ (52%, 47/90) and G+H− (41%, 36/88) was significantly higher than in G−H− (11%, 11/90) and G−H+ (21%, 19/89) (P < 0.05). The total number of cells in the Day 5 blastocysts from G+H+ (34.5 cells) was significantly (P < 0.05) greater than in those from G−H− (25.8 cells). These results suggest that the presence of glutamine and hypotaurine in PZM-5 from Day 2 to Day 3 improves the subsequent development of porcine embryos into blastocysts by reducing intracellular H2O2 levels. This work was supported by MAFF, Japan.

A new additional reporter enzyme, dinoflagellate luciferase, for monitoring of gene expression in mammalian cells

Dinoflagellate luciferase (DL) catalyses the oxidation of dinoflagellate luciferin by molecular oxygen, resulting in an electronically excited species that emits blue light (lambda(max)=474 nm). Luciferase has three catalytic domains in its single polypeptide chain (M(r)=ca. 140 kDa), and each domain (about 40 kDa) is enzymatically active when expressed individually in recombinant fusion proteins in E. coli. Thus, DL should be useful as a reporter enzyme in studies of gene expression in mammalian cells. Expression plasmids consisting of one domain of luciferase (dDL) cDNA linked to different several promoters were introduced into a series of mammalian cell lines. Following transfection, dDL activities in cell extracts were determined by a rapid light emission assay of luciferase activity. For dual and multiple reporter assays, it is possible to exchange dDL for the firefly or renilla luciferases, and use the new luciferase for control or target reporter genes. Thus, the triple-reporter assay can identify three transcriptional activities of different genes at the same time. This work establishes the DL gene as a new efficient marker of gene expression in mammalian cells.

Clinical and pathological differences between Mikulicz's disease and Sjögren's syndrome

OBJECTIVE

Mikulicz's disease (MD) has been included within the diagnosis of primary Sjögren's syndrome (SS), but represents a unique condition involving enlargement of the lachrymal and salivary glands and characterized by few autoimmune reactions and good responsiveness to glucocorticoids. We have previously described elevated immunoglobulin (Ig) G4 in the serum of four patients with MD. In this paper, we accumulated more MD cases and undertook clinical and histopathological analysis of these patients to clarify differences between MD and SS.

METHODS

We diagnosed seven patients with MD according to the following criteria: (i) visual confirmation of symmetrical and persistent swelling in more than two lachrymal and major salivary glands; (ii) prominent mononuclear infiltration of lachrymal and salivary glands; and (iii) exclusion of other diseases that present with glandular swelling, such as sarcoidosis and lymphoproliferative disease. We summarized the clinical and serological characteristics (IgG subclasses and IFN-gamma/IL-4 ratio) of seven patients with MD, compared with SS with glandular swelling (SSw) and without glandular swelling (SSo). After steroid administration, we analysed changes in IgG subclasses in MD. Labial salivary gland specimens in MD, SSw and SSo were stained with anti-IgG4 antibodies.

RESULTS

The concentration (+/-s.d.) of IgG4 was 1169.7 +/- 892.2 mg/dl in MD, 24.4 +/- 7.0 mg/dl in SSw (P<0.005) and 82.6 +/- 189.7 mg/dl in SSo (P<0.005). The IFN-gamma/IL-4 ratio was 0.392 +/- 0.083 (0.78 +/- 0.23/2.14 +/- 0.31 IU/pg) in MD, 0.004 +/- 0.002 (0.20 +/- 0.07/57.02 +/- 14.05 IU/pg) in SSw (P<0.05) and 0.012 +/- 0.009 (0.58 +/- 0.86/116.24 +/- 207.65 IU/pg) in SSo (P<0.05). The concentration (+/-s.d.) of IgG4 in MD decreased to 254.0 +/- 50.3 mg/dl (P<0.05) after glucocorticoid treatment. Histopathologically, only MD was associated with prominent infiltration of IgG4-positive plasmacytes into lachrymal and salivary glands.

CONCLUSION

Mikulicz's disease is quite different from SS clinically and histopathologically. MD is suggested to be an IgG4-related systemic disease.

Identification of zonal flows in a toroidal plasma

This Letter presents experimental confirmation of the presence of zonal flows in magnetically confined toroidal plasma using an advanced diagnostic system--dual heavy ion beam probes. The simultaneous observation of an electric field at two distant toroidal locations (approximately 1.5 m apart) in the high temperature (approximately 1 keV) plasma provides a fluctuation spectrum of electric field (or flow), a spatiotemporal structure of the zonal flows (characteristic radial length of approximately 1.5 cm and lifetime of approximately 1.5 ms), their long-range correlation with toroidal symmetry (n=0), and the difference in the zonal flow amplitude with and without a transport barrier. These constitute essential elements of turbulence-zonal flow systems, and illustrate one of the fundamental processes of structure formation in nature.

Analysis of B-cell clonality in the hepatic tissue of patients with Sjögren's syndrome

OBJECTIVE

We investigated the incidence of B-cell clonality in the minor salivary gland and liver (extra-glandular lesion) of patients with Sjögren's syndrome (SS). We also compared B-cell clonality in the minor salivary gland and liver in the same individuals, and compared its incidence among patients with various liver diseases, such as primary biliary cirrhosis (PBC) and autoimmune hepatitis (AIH).

METHODS

A minor salivary gland biopsy was performed on 35 patients with SS (30 patients with primary SS, and five patients with secondary SS). A liver biopsy was performed on nine patients with SS associated with bile duct lesions, two patients with PBC, one patient with AIH, one patient with drug-induced liver dysfunction, and three patients with viral hepatitis. DNA was extracted from each tissue sample and then subjected to Polymerase Chain Reaction (PCR). B-cell clonality was analysed by assessing the rearrangement of the immunoglobulin heavy chain (IgH) gene by PCR.

RESULTS

B-cell clonality was confirmed in the minor salivary gland biopsy sample in 23 of the 35 patients (65.7%), and in the liver biopsy sample (non-exocrine organ involvement) in seven of the nine patients (77.8%). The presence or absence of B-cell clonality was investigated in both the minor salivary gland and liver in seven patients, but B-cell clonality was confirmed in both tissues in only one patient, and the pattern of clonality in the minor salivary gland differed from that in the liver. B-cell clonality was detected in the liver of the PBC and AIH patients.

CONCLUSION

B-cell clonality is a phenomenon that is observed frequently in SS lesions in the salivary glands and liver. The appearance of B-cell clonality was shown to be attributable to antigen-driven clonal expansion.

Birth of Piglets through the Non-Surgical Transfer of Blastocysts Produced In Vitro

In this study, we attempted to produce piglets by non-surgically transferring blastocysts produced in vitro, using a flexible catheter as the transfer instrument. Cumulus-oocyte complexes (COCs) were aspirated from the follicles of ovaries obtained at a local slaughterhouse. They were then matured in modified North Carolina State University (NCSU)-37 medium for 44-46 h and fertilized in porcine gamete medium (PGM). Ten hours after in vitro fertilization (IVF), presumptive zygotes were removed from the cumulus cells and cultured in porcine zygote medium (PZM)-5. Blastocysts were cultured for five days after IVF and, using a catheter for deep intrauterine insemination without sedation, they were transcervically transferred into the uterine horn of six recipients (45-50 blastocysts/recipients) whose estrous cycles were synchronized, at 5 days after human chorionic gonadotropin (hCG) injection. Of the six recipients, one sow became pregnant and farrowed seven piglets (four live piglets) 119 days after hCG injection. The body weight at birth of the newborns ranged from 0.8 to 1.4 kg. These results indicate that it is possible to obtain piglets by transcervically transferring blastocysts produced by IVF and in vitro cultures in chemically defined media.

285BIRTH OF PIGLETS AFTER NON-SURGICAL TRANSFER OF PORCINE EMBRYOS CULTURED IN PZM-4 WITH ALTERED CONCENTRATIONS OF AMINO ACIDS

We previously developed an in vitro production (IVP) system for porcine embryos and obtained piglets after surgical transfer of blastocysts cultured in Porcine Zygote Medium (PZM)-4. However, the developmental competence of pig IVP embryos to the blastocyst stage is still low and further improvement of IVC medium is needed. In the present study, we evaluated the effects of the addition of glutamine (Gln), hypotaurine (HT), taurine (Tau), BME-essential (EA) and MEM-nonessential (NA) amino acids solutions to PZM-4, and the replacement of polyvinyl alcohol (PVA) with BSA on embryo development to blastocysts. Moreover, the developmental competence of IVP blastocysts after nonsurgical embryo transfer (NS-ET), using a flexible catheter (FC) for deep intrauterine insemination, was investigated. Porcine COC from prepubertal gilts were matured and fertilized in vitro, using frozen-thawed ejaculated boar semen. Presumptive zygotes were cultured in PZM-4, as a basal culture medium, until Day 5 after IVF. Data from six replicates were analyzed by ANOVA. Addition of 0.25 to 4mM Gln to PZM-4 (containing 5mM HT) significantly increased the percentage of embryos that developed to blastocysts (15 to 31%), with addition of 2mM Gln significantly increasing the total cell numbers in blastocysts (43±17 cells) compared with no addition (3% and 20±4 cells, respectively). Addition of 1.25 to 10mM HT to HT-free PZM-4 supplemented with 2mM Gln (named PZM-5) significantly increased the percentage of embryos that developed to blastocysts (22 to 28%) compared with control (no HT;; 4%). In the culture with HT-free PZM-5, addition of 5mM Tau significantly increased blastocyst yield (17%) compared with control (4%). However, Tau addition in the presence of 5mM HT had no effect on development to the blastocyst stage. In combinations of EA and NA added to PZM-5, a single dose of EA significantly increased the percentage of embryos that developed to blastocysts (27%) compared with no dose (19%) or with a double dose of EA (20%), while a double dose of NA significantly increased the total cell numbers in blastocysts (43±16 cells) compared with no NA (37± 6 cells). Replacement of PVA with BSA in PZM-5 had no effect on embryo development to the blastocyst stage. Crossbred sows were used as recipients for NS-ET, and had their estrous cycle synchronized by a described previously method (Yoshioka et al., 2002 Biol. Reprod. 66, 112–119). Five days after hCG injection, a FC was introduced via the cervix into the uterine horn of recipients without sedation. Day-5 blastocysts cultured in PZM-5 were then transferred together with 5ml of TALP-Hepes (45 to 50 blastocysts/recipient). Of 6 recipients, one sow became pregnant and farrowed 7 piglets. Our results indicate that the addition of amino acids to PZM-4 can improve porcine embryo development to the blastocyst stage, and that blastocysts cultured in a chemically defined medium, PZM-5, can develop to full-term following NS-ET.

Production of piglets derived from in vitro-produced blastocysts fertilized and cultured in chemically defined media: effects of theophylline, adenosine, and cysteine during in vitro fertilization

To further develop defined conditions for in vitro fertilization (IVF) and in vitro culture (IVC) of in vitro-matured porcine oocytes, we evaluated the effects of theophylline, adenosine, and cysteine in a chemically defined medium during IVF. Viability to full term of in vitro-produced blastocysts after IVF and IVC in chemically defined medium was also investigated by embryo transfer to recipients. A chemically defined medium, porcine gamate medium (PGM), was modified from porcine zygote medium (PZM-4), which was previously established. PGM was used as a basal medium for IVF and PZM-4 was for the culture of presumptive zygotes. Addition of 2.5 mM theophylline to PGM significantly increased the percentage of male pronuclear formation compared with controls (no addition). Addition of 1 microM adenosine to PGM supplemented either with or without 2.5 mM theophylline significantly reduced the number of penetrated spermatozoa compared with controls (no addition of adenosine). Supplementation with 0.2 microM cysteine in PGM containing both 2.5 mM theophylline and 1 microM adenosine further increased the percentage of development to the blastocyst stage, compared with no supplementation of cysteine, but there was no difference in fertilization parameters, such as monospermy and pronuclear formation, regardless of presence or absence of theophylline and adenosine. When Day 5 blastocysts were transferred into four recipients (20-25 blastocysts per recipient), all recipients became pregnant and farrowed a total of 21 live piglets. The present results clearly demonstrate that porcine blastocysts can be produced by IVF and IVC in chemically defined media and that they can develop to full term after embryo transfer.

Identification of COX17 as a therapeutic target for non-small cell lung cancer

We have been investigating gene expression profiles in non-small cell lung cancers (NSCLCs) to identify molecules involved in pulmonary carcinogenesis and select which genes or gene products might be useful as diagnostic markers or targets for new molecular therapies. Here we report evidence that the cytochrome c oxidase (CCO) assembly protein COX17 is a potential molecular target for treatment of lung cancers. By semiquantitative reverse transcription-PCR, we documented increased expression of COX17 in all of 8 primary NSCLCs and in 11 of 15 NSCLC cell lines examined, by comparison with normal lung tissue. Treatment of NSCLC cells with antisense S-oligonucleotides or vector-based small interfering RNAs of COX17 suppressed expression of COX17 and also the activity of CCO, and suppressed growth of the cancer cells. Because our data imply that up-regulation of COX17 function and increased CCO activity are frequent features of lung carcinogenesis, we suggest that selective suppression of components of the CCO complex might hold promise for development of a new strategy for treating lung cancers.

Localization of influenza virus proteins to nuclear dot 10 structures in influenza virus-infected cells

We studied influenza virus M1 protein by generating HeLa and MDCK cell lines that express M1 genetically fused to green fluorescent protein (GFP). GFP-M1 was incorporated into virions produced by influenza virus infected MDCK cells expressing the fusion protein indicating that the fusion protein is at least partially functional. Following infection of either HeLa or MDCK cells with influenza A virus (but not influenza B virus), GFP-M1 redistributes from its cytosolic/nuclear location and accumulates in nuclear dots. Immunofluorescence revealed that the nuclear dots represent nuclear dot 10 (ND10) structures. The colocalization of authentic M1, as well as NS1 and NS2 protein, with ND10 was confirmed by immunofluorescence following in situ isolation of ND10. These findings demonstrate a previously unappreciated involvement of influenza virus with ND10, a structure involved in cellular responses to immune cytokines as well as the replication of a rapidly increasing list of viruses.

Effect of mono-(2-ethylhexyl) phthalate on bovine oocyte maturation in vitro

The effect of mono(2-ethylhexyl) phthalate (MEHP) on bovine oocyte maturation in vitro was examined. Cumulus-oocyte complexes (COCs) were cultured in maturation medium supplemented with various levels of MEHP for 24h, and then examined for the degree of cumulus expansion and the stage of maturation. A higher percentage of oocytes remained at the germinal vesicle (GV) stage after exposure to 75 and 100 micro M MEHP treatments (13.8 and 44.9% of oocytes, respectively) than the control (2.1% of oocytes). The proportion of oocytes that progressed to the metaphase II (MII) stage was significantly decreased with 25 micro M (59.6% of oocytes), 50 micro M (19.8%), 75 micro M (21.3%), and 100 micro M (3.1%) treatments than the control (77.3%). MEHP did not affect the process of cumulus expansion. For denuded oocytes, MEHP treatment of 50-100 micro M resulted in a significantly higher rate of oocytes remained at the GV stage compared to the control (53.4, 80.2, 88.4, and 5.4%, respectively). The rate of MII formation was significantly decreased with 10 micro M (60.9%) and 25 micro M (22.5%) MEHP treatments compared to control (68.9%). Furthermore, with 50, 75 or 100 micro M MEHP, no oocyte reached the MII stage. When COCs were cultured for 24h with 50 or 100 micro M MEHP and then cultured for an additional 24h in MEHP-free medium, most of the oocytes reached the MII stage (71.1 and 64.5%, respectively).Taken together, these results indicate that MEHP, at doses lower than those reported in blood transfusion patients, could negatively modulate bovine oocyte meiotic maturation in vitro, suggesting possible risks for human and other mammalians reproductive health.

Smurf1 regulates the inhibitory activity of Smad7 by targeting Smad7 to the plasma membrane

Smad ubiquitin regulatory factor 1 (Smurf1), a HECT-type E3 ubiquitin ligase, interacts with inhibitory Smad7 and induces cytoplasmic localization of Smad7. Smurf1 then associates with transforming growth factor-beta type I receptor (TbetaR-I) and enhances the turnover of this receptor. However, the mechanisms of the nuclear export and plasma membrane localization of the Smurf1.Smad7 complex have not been elucidated. We show here that Smurf1 targets Smad7 to the plasma membrane through its N-terminal conserved 2 (C2) domain. Both wild-type Smurf1 (Smurf1(WT)) and Smurf1 lacking the C2 domain (Smurf1(deltaC2)) bound to Smad7 and translocated nuclear Smad7 to the cytoplasm. However, unlike Smurf1(WT), Smurf1(deltaC2) did not move to the plasma membrane and failed to recruit Smad7 to the cell surface TbetaR-II.TbetaR-I complex. Moreover, although Smurf1(deltaC2) induced ubiquitination of Smad7, it failed to induce the ubiquitination and degradation of TbetaR-I and did not enhance the inhibitory activity of Smad7. Thus, these results suggest that the plasma membrane localization of Smad7 by Smurf1 requires the C2 domain of Smurf1 and is essential for the inhibitory effect of Smad7 in the transforming growth factor-beta signaling pathway.

Urinary excretion of 8-oxo-7, 8-dihydro-2'-deoxyguanosine as a predictor of the development of diabetic nephropathy

AIMS/HYPOTHESIS

The increased oxidative stress in diabetes is known to contribute to the progression of diabetes and its complications. We have reported a significant relation between the content of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), a product of oxidative DNA damage in urine or leukocytes and the severity of diabetic nephropathy and retinopathy [1]. We investigated whether 8-oxodG in urine or leukocytes is associated with the progression of diabetic nephropathy.

METHODS

We measured urinary 8-oxodG contents at entry and carried out a prospective longitudinal study to assess the progression of nephropathy over 5 years.

RESULTS

There was a significant progression of diabetic nephropathy in the patients with higher excretion of 8-oxodG in urine compared with the patients with moderate or lower excretion of 8-oxodG. There was no significant association between the leukocyte 8-oxodG contents and the development of nephropathy. The multivariate logistic regression analysis suggests that the urinary 8-oxodG was the strongest predictor of nephropathy among several known risk factors.

CONCLUSION/INTERPRETATION

This study provides evidence that increased oxidative stress has a primary role in the pathogenesis of diabetic nephropathy. A local enhancement of oxidative stress in diabetic kidney might explain the possible linkage between the increased urinary excretion of 8-oxodG and the development of nephropathy. 8-oxodG in urine is a useful clinical marker to predict the development of diabetic nephropathy in diabetic patients.

Alternative CUG codon usage (Ser for Leu) in Pichia farinosa and the effect of a mutated killer gene in Saccharomyces cerevisiae

The halotolerant yeast Pichia farinosa KK1 strain produces a killer toxin termed SMKT (salt-mediated killer toxin). Mass spectrometry and Edman sequencing of peptides from the mature SMKT and secreted protoxin demonstrate that positions specified by the CUG codon contain unmodified serine (Ser) in P.farinosa. In order to express the authentic SMK1 product in Saccharomyces cerevisiae, which uses the universal genetic code, the three CUG codons corresponding to Ser87, Ser137 and Ser206 in the SMK1 gene were changed to universal Ser codons by site-directed mutagenesis. The expression of the modified SMK1 gene with universal Ser codons was lethal in S.cerevisiae, as well as that of the unmodified SMK1 gene with the CUG codons. The secretion of protoxin with the authentic amino acid sequence from the modified SMK1 was significantly increased, whereas the transcription level of SMK1 was not affected in the presence or absence of CUG codon. Our results provide the first in vivo evidence that non-universal decoding of CUG is used in a hemiascomycetous yeast, P.farinosa.

Birth of piglets derived from porcine zygotes cultured in a chemically defined medium

We evaluated the in vitro development of porcine zygotes that were cultured in a novel culture medium, porcine zygote medium (PZM), under different conditions and compared to in vivo development. The viability of these zygotes to full term after culture was also evaluated by embryo transfer to recipients. Porcine single-cell zygotes were collected from gilts on Day 2 after hCG injection. Culture of zygotes in PZM containing 3 mg/ml of BSA (PZM-3) produced better results in terms of proportion of Day 6 blastocysts, Day 8 hatching rate, and numbers of inner cell mass (ICM) cells and total cells in Day 8 embryos than that in North Carolina State University (NCSU)-23 medium. In culture with PZM-3, embryo development was optimized in an atmosphere of 5% CO2:5% O2:90% N2 compared to 5% CO2 in air. The ICM and total cell numbers in Day 6 embryos cultured in PZM-3 or in PZM-3 in which BSA was replaced with 3 mg/ml of polyvinyl alcohol (PZM-4) were also greater than those of NCSU-23 but less than those developed in vivo. However, no difference was found in the ratio of ICM to total cells among embryos developed in PZM-3, PZM-4, or in vivo. When the Day 6 embryos that developed in PZM-4 (99 embryos) or in vivo (100 embryos) were each transferred into six recipients, no difference was found in the farrowing rate (83.3% for both treatments) and in the number of piglets born (33 and 42 piglets, respectively). Our results indicate that porcine zygotes can develop into blastocysts in a chemically defined medium and to full term by transfer to recipients after culture.

Interaction of SMKT, a killer toxin produced by Pichia farinosa, with the yeast cell membranes

SMKT (salt-mediated killer toxin), a killer toxin produced by the halotolerant yeast, Pichia farinosa, kills yeasts of several genera, including Saccharomyces cerevisiae. To elucidate the killing mechanism of SMKT, we examined the interaction of SMKT with membranes using liposomes. Leakage of calcein from calcein-entrapped liposomes was observed in the presence of SMKT. Destruction of liposomes was observed by dark-field microscopy. Comparison of intact S. cerevisiae cells with SMKT-treated cells by dark-field microscopy indicated that the spherical cell membrane is disrupted by SMKT. Using sodium carbonate extraction, we obtained direct evidence for the first time that SMKT is associated with the membrane of sensitive cells. Our results indicate that SMKT kills sensitive S. cerevisiae by interacting with the yeast cell membrane.

Immunochemical and mutational analyses of P-type ATPase Spf1p involved in the yeast secretory pathway

The yeast SPF1 gene encodes a novel P-type ATPase, the substrate of which specificity has not been identified. It is required for sensitivity to SMKT, a killer toxin produced by the halotolerant yeast Pichia farinosa. To investigate the function of Spf1p, Asp487, the putative phosphorylation site of Spf1p, was replaced by Asn. Expression of the altered SPF1, with Asp487 replaced by Asn, did not suppress the SMKT-resistant phenotype of spf1 mutants, suggesting that the catalytic activity of this ATPase is required for acquisition of sensitivity to SMKT. Subcellular fractionation experiments indicated that the fractionation pattern of Spf1p was similar to that of an early Golgi protein, Och1p. Cells lacking Spf1p had an abnormal fractionation pattern of Sec12p. The spf1 disruptant also showed increased expression of Kar2p and sensitivity to tunicamycin. The glycosylation-defective phenotype and possible role of Spf1p in the secretory pathway are discussed.

Temporal bone histopathology in trisomy 22

Trisomy 22 has multiple physical anomalies, and aural malformations are commonly associated with trisomy 22. However, there has been only one report describing the temporal bone histopathology in trisomy 22. Our case is the second reported temporal bone histopathology of trisomy 22. Aural anomalies in this case were less serious than those earlier described, though showing Mondini dysplasia of the bony and membranous labyrinth. Deafness in patients with trisomy 22 may manifest sensorineural, conductive or mixed hearing losses, and/or vestibular dysfunction of varying degrees, according to the site and severity of aural anomalies.

HBe seroconversion and HBs mutation among Japanese hepatitis B virus carriers

It has been reported in Germany that seroconversion to anti-HBe or anti-HBs is frequently associated with genotype changes of hepatitis B virus (HBV) from genotype A to genotype D. We previously reported that the HBeAg-negative state in Japan was significantly more common in patients infected with genotype B HBV than those infected with genotype C HBV. To determine whether the high prevalence of genotype B in the HBeAg-negative state is due to a change from genotype C to genotype B, 72 pairs of serum samples before and after HBe seroconversion were examined for nucleotide sequences in the S gene (amino acids 42-164) among Japanese HBV carriers. No one was identified to have undergone genotype change during HBe seroconversion. A total of 71 codon mutations were observed. Sixty-two of these 71 codon mutations (87.3%) were non-synonymous. Genotype B HBV had no mutational hot spots. In genotype C, there was a mutational hot spot at amino acid 126 of the S protein, and it was suggested that Thr126 before HBe seroconversion was more susceptible to becoming an asymptomatic carrier after HBe seroconversion than Ile126. In conclusion, genotype changes during HBe seroconversion were not found to be common in Japan.

Identification and allelic frequencies of novel single-nucleotide polymorphisms in the DUSP1 and BTG1 genes

Defects in the activity of the PTEN gene, a tumor suppressor, are implicated in many types of cancer in humans. However, not all mediators of PTEN signaling pathways have been clarified, and, during efforts to identify such molecules, we previously induced expression of the DUSP1 and BTG1 genes by introducing exogenous PTEN into endometrial cancer cell lines. In the course of analyzing these two genes for mutations in ovarian carcinomas, we identified a novel single-nucleotide polymorphism (SNP) in the DUSP1 gene, and three novel SNPs in the BTG1 gene, and we have established their allelic frequencies in a Japanese population sample. These polymorphic sites will be useful for detecting losses of heterozygosity (LOH) in tumors and for examining latent associations between specific alleles and disease susceptibility.

Characteristics of the cell proliferation profile of activated rat hepatic stellate cells in vitro in contrast to their fibrogenesis activity

PURPOSE

Alterations in the kinetics of hepatic stellate cells (HSCs) after the cells are activated once have not been well documented. We investigated the characteristic profiles of cell proliferation of once-activated HSCs in contrast to the in fibrogenesis activity.

METHODS

HSCs from male Wistar rats were submitted to primary culture for 14 days and to secondary culture for 7 days. The potential for cell proliferation was evaluated by the number of the cells in G2/M phase, based on flow cytometric analysis of the cell cycle. The fibrogenesis activity was assessed by Northern blot analysis of the expression of type I and type III procollagen mRNA.

RESULTS

The number of HSCs in G2/M phase was maintained at a low level in primary culture after 6 days, while a significantly (P < 0.05) elevated number of HSCs in G2/M phase was observed on days 3 to 4. In secondary culture, the number of HSCs in G2/M phase was also consecutively maintained at a decreased level. By contrast, HSCs showed progressively increased type I and type III procollagen mRNA expression during the experimental periods of primary culture.

CONCLUSIONS

These results clearly demonstrated consecutively decreased proliferative activity, evaluated by the potential for cell mitogenesis, in once-activated HSCs, in contrast to their progressively increased fibrogenesis activity.

Endotoxin induces delayed ovulation following endocrine aberration during the proestrous phase in Holstein heifers

The effect of endotoxin on follicular growth and on secretion of LH, estradiol-17beta, progesterone and cortisol during the proestrous phase in cattle was investigated. Holstein heifers were treated with PGF2alpha at 11-13 d after ovulation to induce luteolysis. At 42 hr after PGF2alpha treatment, heifers were administered either lipopolysaccharide (LPS; Escherichia coli, O111:B4, 5 microg/kg, n = 6) or saline (control; n = 6) by i.v. bolus injection. Ovarian structures were monitored daily by transrectal ultrasonography, and blood samples were collected at various times for hormonal analysis. The duration from PGF2alpha treatment to ovulation was significantly longer in the LPS group (8.0 +/- 1.3 d) than in the control group (4.2 +/- 0.2 d). LPS significantly reduced the pulse frequency of LH for 6 hr after the administration, and increased the mean concentration and pulse amplitude of LH from 3 to 6 hr after the administration. The plasma concentrations of progesterone and cortisol were transiently increased after LPS administration. The plasma concentration of estradiol-17beta was significantly decreased at 24 hr after LPS administration compared to that in the controls. Five of six LPS-treated heifers exhibited no preovulatory LH surge until 120 hr after PGF2alpha treatment and the remaining heifer exhibited the surge at 108 hr after PGF2alpha treatment, while the LH surge was observed at 54-78 hr after PGF2alpha treatment in control heifers. These results suggest that endotoxin disrupts progression of the proestrous phase of cattle, interrupting the preovulatory estradiol rise and thus delaying the LH surge and the subsequent ovulation.

HBV-related fulminant hepatic failure: successful intensive medical therapy in a candidate for liver transplantation

Fulminant hepatic failure (FHF) usually has a fatal prognosis without liver transplantation. We describe the case of a woman who developed FHF, and was evaluated as a candidate for liver transplantation, but who was cured without transplantation through intensive medical care that included glucagon-insulin therapy, methylprednisolone pulse therapy, interferon beta and lamivudine administration, cyclosporine administration, and high-volume hemodiafiltration and plasma exchange. In a patient with FHF who is a candidate for liver transplantation but for whom the transplantation cannot be performed for some reason, intensive medical therapy, including regeneration-promoting therapy, immunosuppressive therapy, antiviral therapy, and vigorous hepatic support, should be carried out.

Observation of toroidal flow antiparallel to the <E(r) x B(straight theta)> drift direction in the hot electron mode plasmas in the compact helical system

A toroidal flow antiparallel to the <E(r) x B(straight theta)> drift direction is observed in the hot electron mode plasmas when a large positive electric field and a sharp electron temperature gradient are sustained inside the internal transport barrier in the Compact Helical System. This toroidal flow reaches up to 5x10(4) m/s at the plasma center, and it is large enough to reverse the toroidal flow driven by a tangentially injected neutral beam. These observations clearly show the plasma favors flow in the minimum nablaB direction at the transport barrier.

Temporal bone findings in multiple endocrine neoplasia type 2B

To our knowledge, present case is the first published report of temporal bone findings in multiple endocrine neoplasia type 2B (MEN-2B). We describe a 43-year-old Japanese man with medullary thyroid carcinoma (MTC), pheochromocytoma, mucosal neuroma and a Marfanoid body habitus. The collateral adrenal tumors and MTC were removed surgically. However, 14 years after surgery, the MTC and pheochromocytoma recurred and the patient died of intracranial hemorrhage due to hypertension. During the autopsy, metastatic MTC was detected in the liver, lungs, kidneys, pancreas and cervical lymph nodes. Recurrent pheochromocytoma was present in the right kidney. Mucosal neuromas were found in the tongue, gastrointestinal tract and vesical nerve plexus. The following histopathological findings were seen in both temporal bones: metastatic MTC was found as well as neuromas and the cochlear aqueduct was widely patent.

Gonadotropin-releasing hormone in third ventricular cerebrospinal fluid of the heifer during the estrous cycle

The release profile of GnRH in cerebrospinal fluid (CSF) and its correlation with LH in peripheral blood of ovary-intact heifers during the estrous cycle were investigated. A silicon catheter was placed into the third ventricle of six heifers using ultrasonography. During the mid-luteal phase, the heifers were injected with prostaglandin F(2alpha) to induce luteolysis. Surges of CSF GnRH (66.7 h after prostaglandin F(2alpha) administration) and peripheral LH (66.3 h) occurred simultaneously and were coincident with the onset of estrus (67.0 h). Duration of elevated GnRH concentration considerably overlapped with the estrous phase in each of the heifers. Mean pulse frequencies of both GnRH and LH were significantly higher during the proestrous and early luteal phases than during the mid-luteal phase, while mean concentration and pulse amplitude of both GnRH and LH were not different between these three phases. Of all the GnRH pulses identified, more than 80% were accompanied by an LH pulse during the proestrous and early luteal phases. However, the proportion of GnRH pulses that were coincident with an LH pulse during the mid-luteal phase decreased to 60%. The results clearly demonstrate that a dynamic (pulse) and longer-term (surge) changes of GnRH release into CSF are physiologically expressed during the estrous cycle in heifers, and the pattern of pulsatile GnRH secretion in heifers depends upon their estrous cycle.

Temporal bone pathology in Wegener's granulomatosis

This study aimed to demonstrate the temporal bone histopathology of two cases of Wegener's granulomatosis in which the initial symptoms were profound hearing loss and facial nerve palsy respectively. The first case, a woman of 44, suffered profound hearing loss which was remarkably improved by steroid and cyclophosphamide treatment for a time, and which seemed to be caused by invasion from granulation tissue filled in the tympanic cavity. The second case was a 61-year-old woman presenting with the facial nerve palsy. The bony canal of the horizontal portion of the facial nerve was destroyed due to granulation tissue which filled in the tympanic cavity, and granulomatous involvement was observed in the facial nerve. Wegener's granulomatosis can involve the middle ear and/or inner ear, causing hearing loss of conductive, mixed or sensorineural type. Pathogenesis of facial nerve palsy seems to be related to Wegener's granulomatous involvement of facial nerve, because the facial nerve palsy also resolved by using steroid and cyclophosphamide.

Cancer regression induced by modified CTL therapy is regulated by HLA class II and class I antigens in Japanese patients with advanced cancer

Autologous cancer-specific bulk CTLs are unlikely to be induced by in vitro CTL generation (ivtCTLG) using peripheral blood mononuclear cells (PBMCs) of cancer patients when autologous cancer cells are used as in vitro stimulators. However, autologous cancer-specific bulk CTLs are frequently activated when allogeneic cancer cells are used as in vitro stimulators, regardless of the type of cancer cell. We have developed a cancer-specific immunotherapy called modified CTL therapy, which involves adoptive immunotherapy of autologous cancer-specific bulk CTLs after active immunization of autologous or allogeneic cancer cells screened as in vitro stimulators according to their ability to induce autologous cancer-specific CTLs (ACS. CTLs). Cancer did not regress in patients in whom ACS.CTLs were not induced by ivtCTLG using the patients' PBMCs in therapy. Cancer regression, albeit temporary, occurred solely in patients under the immunological condition that ACS.CTLs were induced by ivtCTLG using PBMCs through the therapy. The induction of ACS.CTLs by ivtCTLG using patient PBMCs in therapy was related to patients' HLA class II antigens. HLA DR8 was seen more frequently in ACS.CTL-inducible patients than in ACS.CTL-uninducible patients (P=0.051). On the contrary, HLA DQ3 was seen more frequently in ACS.CTL-uninducible patients (P=0.055). On the other hand, the success in therapy, albeit temporary, was related mainly to patients' HLA class I antigens. HLA B61 was seen more frequently in patients whose therapy proved effective than in patients whose therapy proved ineffective (P=0.018). HLA Cw7 was seen more frequently in therapy-ineffective patients (P=0.040).

Open sandwich enzyme-linked immunosorbent assay for the quantitation of small haptens

The quantitation of low-molecular-weight haptens has been difficult with conventional sandwich immunoassays due to their small size. Many researchers have attempted to develop sandwich assays for haptens due to the significant advantages of the sandwich format over competitive assays including greater dynamic range, ease of automation, and sensitivity. Here we apply the open-sandwich ELISA (OS-ELISA), an immunoassay based on antigen-dependent stabilization of antibody variable regions (V(H) and V(L) domains), to hapten quantitation. Two fusion proteins, the high-affinity mutant V(H) domain from anti-4-hydroxy-3-nitrophenacetyl (NP) antibody B1-8 tethered with Escherichia coli alkaline phosphatase (V(H)(W33L)-PhoA) and the V(L) domain from the same antibody tethered with Streptococcus sp. protein G, were made. These fusion proteins when added together achieved Fv reassociation consequent to the addition of NP. Signal was generated in a direct relationship to the NP concentration with better sensitivity compared with competitive immunoassay, demonstrating this assay to be a quick noncompetitive alternative to the conventional assays for small compounds, such as environmental pollutants, drugs of abuse, and therapeutic drugs. With our previous demonstration that the OS-ELISA works well with large proteins, the OS-ELISA becomes the first practical immunoassay approach capable of quantifying any molecule regardless of their size.

A case of purpura fulminans is caused by homozygous delta8857 mutation (protein C-nagoya) and successfully treated with activated protein C concentrate

We report a Japanese patient who developed purpura fulminans and disseminated intravascular coagulation (DIC) shortly after birth. The patient was diagnosed to be homozygous for protein C deficiency and was treated with an activated protein C (APC) concentrate. Intravenous infusions of APC markedly improved the necrotic skin lesions and the anticoagulation by APC enabled successful DIC control. The identified mutation (Delta8857) results in impaired intracellular transport and protein maturation and would be the cause of the complete protein C deficiency. This is the seventh case of the mutation that has been exclusively reported in Japan, but is the first report of a homozygous case. Our findings propose new therapeutic and diagnostic tools for the management of this fatal thrombotic disease.

[Comparison of microfissures between the oval and round window niche areas in human temporal bone]

There are numerous reports on microfissures in the round window niche area, but not many reports have appeared on microfissures in the oval window niche area. In addition, few studies have compared microfissures between the oval and round window niche areas in the same subjects. Hence, the present study investigated the prevalence of microfissures in both areas in human temporal bones. The study was conducted on the 637 ears of 333 cases. Specimens were prepared according to the conventional methods: after fixation, decalcification and dehydration, each specimen was embedded in Celloidin, and the temporal bones were sectioned horizontally at 25-micron intervals. Every 10th section was stained with hematoxylin & eosin, and each section was analyzed under a light microscope. The prevalence of microfissures was analyzed in relation to the sex, left/right differences and age of the subjects. Microfissures were seen in the oval window niche area in 66.2%, and in the round window niche area in 92.0%. When a microfissure was seen in the oval window niche area, it was also detected in the round window niche area in every case. There were no sex or left/right differences in the prevalence of microfissures, and microfissures occurred bilaterally in most cases. The youngest subject with a microfissure in the oval window niche area was a 14-year-old, and the prevalence increased with age up to approximately 60 years. On the other hand, microfissures in the round window niche area were seen in a 3-year-old, and were seen in most cases over the age of ten. These findings suggest that microfissures are more likely to occur in the round window niche area as compared to the oval window niche area. However, the prevalence of microfissures in the oval window niche area was not low either, and it is important to pay attention to both the oval and round niche areas when microfissures are involved in the formation of perilymph fistulae. Given that the prevalence of microfissures in the oval window niche area increased up to about 60 years of age, not only growth, but also mastication, may be involved in the occurrence of microfissures.

Length of the eustachian tube and its postnatal development: computer-aided three-dimensional reconstruction and measurement study

Eleven normal human temporal bone-eustachian tube (ET) specimens obtained from 11 individuals whose ages were 3 months to 88 years were studied to investigate the path length along the ET lumen and its postnatal development by means of a computer-aided 3-dimensional reconstruction and measurement method. The path length of the ET lumen of the 3-month-old infant was 21.2 mm, and its growth was in correlation with age to attain its adult length (average, 37.00 +/- 4.16 mm). The ratio of the length of the cartilaginous portion together with the junctional portion to the length of the bony portion was 8:1 in an infant at the age of 3 months and 4:1 in adults. That the bony portion of the ET develops relatively more than the cartilaginous and junctional portions may cause this finding. In addition, there is a developmental shift in the orientation of the cartilaginous portion with respect to the bony portion of the ET. In children, the cartilaginous and bony portions are both aligned with the line that connects the pharyngeal orifice and the tympanic orifice. In adults, however, the cartilaginous portion is angled inferiorly and laterally from the bony portion. This change may reflect the relative growth of the face.

Peripheral and central conduction abnormalities in diabetes mellitus

OBJECTIVES

To investigate peripheral and central somatosensory conduction in patients with diabetes.

METHODS

The authors recorded sensory nerve action potentials and 5-channel somatosensory evoked potentials (SEPs) with noncephalic reference after median nerve stimulation in 55 patients with diabetes and 41 age- and height-matched normal subjects. The authors determined onset or peak latencies of the Erb's potential (N9) and the spinal N13-P13 and the cortical N20-P20 components, and obtained the central conduction time (CCT) by onset-to-onset and peak-to-peak measurements.

RESULTS

Both onset and peak latencies of all SEP components were prolonged in patients with diabetes. The mean onset CCT in the diabetic group was 6.3 +/- 0.5 msec (mean +/- SD)-significantly longer than that in the control group (6.1 +/- 0.2 msec)-whereas no significant difference was found in the peak CCT. The amplitudes of N9 and N13-P13 components (but not N20-P20) were significantly smaller in the diabetic group. The peripheral sensory conduction velocity was also decreased in the diabetic group, but there was no significant correlation between peripheral conduction slowing and the onset of CCT prolongation.

CONCLUSIONS

Diabetes affects conductive function in the central as well as peripheral somatosensory pathways. The CCT abnormality does not coincide with lowering of the peripheral sensory conduction. The current results do not favor a hypothesis that a central-peripheral distal axonopathy plays an important role in development of diabetic polyneuropathy.