Biomedical subjects

M Itoh

Publications and source records attributed to M Itoh.

At least 379 records · Page 21Linked to original sources

PubMed1998

Essential pathogenic role for endogenous interferon-gamma (IFN-gamma) during disease onset phase of murine experimental autoimmune orchitis. I. In vivo studies.

We previously found that immunization of CH3/He male mice with syngeneic testicular germ cells (TGC) without the aid of any adjuvants was sufficient to induce DTH to TGC and experimental autoimmune orchitis (EAO). To evaluate the role of endogenous IFN-gamma in this model, C3H/He mice immunized subcutaneously with TGC on days 0 and 14 received a single injection of anti-murine IFN-gamma MoAb on day 15, 20 or 25. On day 45, DTH to TGC was tested, testis specimens were collected for histological examination, and blood samples collected for IFN-gamma measurement. The results showed that whilst MoAb treatment on day 15 or 25 did not influence DTH responses, EAO development, and appearance of IFN-gamma in the circulation, treatment on day 20 significantly suppressed all of them. Thus, a single injection with anti-IFN-gamma MoAb may successfully down-regulate testicular autoimmunity, provided that the treatment is given at an optimal time point during disease development.

Animals↗

PubMed1998

Surface expression and release of soluble forms of CD8 and CD23 in CD40- and IL-4-activated mononuclear cells from patients with Graves' disease (GD).

We investigated the effect of T cell-dependent B cell activation on the surface expression and release of the soluble forms of CD8 and CD23 by peripheral blood mononuclear cells (PBMC) obtained from patients with GD, versus patients with Hashimoto's thyroiditis, and normal controls. Incubating the PBMC with anti-CD40 MoAbs and IL-4 increased the soluble CD23 levels in cells from all three groups. An increase in the number of CD23+ cells was observed in the PBMC from the patients with GD, but not in PBMC from Hashimoto's thyroiditis or controls. Less soluble CD8 was released from anti-CD40 antibody and IL-4-stimulated PBMC obtained from patients with GD relative to those from the controls. In addition, the number of CD8+ cells was significantly reduced in stimulated PBMC from the GD patients relative to those from controls. Incubation of PBMC with anti-CD40 antibody plus IL-4 did not affect the proportions of CD4+, CD20+, Fas+ CD4+, and Fas+ CD8+ cells. The addition of T3 to cultured PBMC from controls did not reproduce the changes in CD23+ and CD8+ cells noted in the samples froin GD patients. Thus, T cell-dependent B cell activation, mediated by a CD40 pathway, may reduce the number of CD8+ cells, causing exacerbation of GD.

Adult↗

PubMed1998

Altered expression of membrane inhibitors of complement in human gastric epithelium during Helicobacter-associated gastritis.

AIMS: Membrane inhibitors of complement are thought to protect bystander cells from complement mediated damage. Expression of these proteins is enhanced in the colonic mucosa of patients with ulcerative colitis. Our aim was to investigate the regulation of complement activity in Helicobacter-associated chronic gastritis. METHODS AND RESULTS: We immunohistochemically assayed expression of three membrane inhibitors of complement, decay accelerating factor (DAF; CD55), 20 kDa homologous restriction factor (HRF20; CD59) and membrane cofactor protein (MCP; CD46), in 55 biopsy specimens of the human gastric mucosa. DAF, expressed in 33 (60%) of biopsy specimens, and HRF20, expressed in 45 (82%) of the samples, were located mainly on the apical surface of the epithelial cells, whereas MCP, expressed in 48 (87%) of the biopsies, was found on the basolateral surface. We found strong correlation between expression of DAF on gastric mucosal epithelium and the severity of mucosal infiltration of neutrophils (rs = 0.875, P < 0.0001) and mononuclear cells (rs = 0.773, P < 0.0001). No significant correlation was observed between HRF20 expression and neutrophil or mononuclear cell infiltration, while there was a weak negative correlation between MCP expression and these cellular infiltrations. When we assayed immunostaining of Helicobacter pylori (H. pylori) in these biopsy specimens, strong correlation with the degree of neutrophil (P < 0.0001) and mononuclear cell (P < 0.0001) infiltration were observed. The expression of DAF and H. pylori infection in these biopsies were also significantly (P < 0.0001) correlated. No correlation between HRF20 expression and H. pylori infection was observed, but we did find a significant negative correlation (P < 0.005) between the expression of MCP and H. pylori infection. CONCLUSIONS: Our results, demonstrating altered expression of membrane inhibitors of complement in gastric mucosa during inflammation and/or H. pylori infection, suggest that complement may significantly participate in the pathology of gastric inflammation. Moreover, DAF and MCP may play an important role in the regulation of complement activation in the alimentary tract.

Antigens, CD↗

PubMed1998

Topographical uptake of blood-borne horseradish peroxidase (HRP) in the murine testis at the light microscopic level.

Light microscopical studies on the uptake of blood-borne horseradish peroxidase (HRP) in large areas of the testis have been scarce because of the difficulty of staining HRP in testes with well-preserved morphology. However, observation of exogenous HRP in all areas of the testis enables detection of regional tissue injury induced by toxic chemicals or immunization. In the present study, the localization of blood-borne HRP in the murine testis was investigated light microscopically using plastic-embedded testes and post-embedding histochemical methods. Mice were injected intravenously with HRP, and then perfused with 2.5% glutaraldehyde and 3% paraformaldehyde in 0.1 M phosphate buffer. The fixed testes were immediately removed, dehydrated, and then embedded in plastic without cutting them into small pieces. The prepared sections treated by the diaminobenzidine method exhibited intense HRP activity with well-preserved testis morphology. It was noted that many interstitial macrophages had endocytosed HRP. In particular, HRP-endocytosing macrophages were concentrated around the tubuli recti. The testicular capsule, containing many lymphatic capillaries and vessels, was also loaded with HRP. In the subcapsular interstitium, free HRP in the lymph space accumulated, but the staining intensity was weak compared to that in testicular macrophages. No HRP infiltration into the lumen of the seminiferous tubules was observed at the light microscope level; however, HRP staining was detected in tubular walls and epithelial cells lining the rete testis and tubuli recti, indicating that these regions are permeable to HRP.

Animals↗

PubMed1998

Immunohistochemical detection of testicular macrophages during the period of postnatal maturation in the mouse.

In the present study, the distribution of F4/80, a highly specific antigen of murine macrophages, was studied in the testes of maturing ICR mice to investigate postnatal development of testicular macrophages. The antigen was immunohistochemically identified at the light microscopic level on days 0, 7, 14, 21, 28 and 42 and at 8 weeks after birth. Only a few macrophages were present between developing seminiferous tubules on day 0, but by day 7, the cell density of macrophages in the interstitium was significantly increased. Although the cell processes of the macrophages were very short on days 0 and 7, it was found that their cell processes were extended on days 14 and 21. On day 28, it was observed that the cell density of macrophages increased further and their cell processes became longer, resulting in the formation of a network between adjacent macrophages. Thereafter, the interstitial spaces were found to be narrower due to the increasing diameter of developing seminiferous tubules, although similar physical contact between the testicular macrophages to that seen on day 28 was evident. Moreover, the cell density of macrophages at 8 weeks of age did not differ significantly compared with that on day 28. These results demonstrate that testicular macrophages develop rapidly for the first 4 weeks in the mouse testis.

Animals↗

PubMed1998

Overexpression of CAF1 encoding a novel Ca2+-binding protein stimulates the transition of Dictyostelium cells from growth to differentiation.

Among the expressed genes associated with the switch-over of Dictyostelium cells from cell proliferation to differentiation, the Calfumirin-1 (CAF1) gene has been shown to be preferentially expressed at the initial step of differentiation, encoding a novel Ca2+-binding protein (Abe & Maeda 1995). To analyze precisely the function of CAF1, transformants overexpressing the CAF1 mRNA at the vegetative growth phase and also CAF1-null mutants were prepared, and their developmental features were compared with those of parental wild-type cells. As a result, the CAF1-overexpression was found to promote cell differentiation, possibly through prompt induction of the cAMP receptor 1 (CAR1) gene expression. In addition, the CAF1-overexpressing cells were able to differentiate even under low external Ca2+ ([Ca2+]e) conditions around 10(-6) mol/L at which non-transformed wild-type cells never differentiated. Unexpectedly, however, the CAF1-null mutant produced by homologous recombination exhibited apparently normal development to form fruiting bodies on non-nutrient agar. These results seem to indicate that CAF1-overexpression has a stimulatory effect on differentiation, but that the CAF1 protein is not necessarily required for the phase-shift of cells from growth to differentiation.

Animals↗

PubMed1998

Cerebral blood flow correlated with carotid blood flow in neurologically normal elderly with severe white matter lesions.

Previous studies of white matter signal hyperintensity (WMSH) on T2-weighted MRI (magnetic resonance imaging) have shown it to be related to decreased cerebral blood flow (CBF). However, there have been few studies on the relationship of WMSH and the internal carotid blood flow (CaBF). Doppler ultrasound sonography is widely used for evaluation of CaBF. We analyzed the relationship between CBF, CaBF, and WMSH. The subjects had not suffered cerebral ischemic episodes although they had some risk factors for stroke. They received MRI and were classified into three groups, i.e. mild, moderate, and severe WMSH. The % stenosis of the internal carotid artery (ICA) was measured with angiography. Doppler sonography was used to measure the mean bilateral CaBF. The oxygen-15 steady-state technique and PET (positron emission tomography) were used to measure CBF. There were significant correlations between the % stenosis of ICA and the ipsilateral CaBF and between the % stenosis of ICA and hemispheric CBF. There was a significant relationship between CBF and CaBF in the severe WMSH group, remaining significant after partialling out of the effects of the % stenosis. This indicated that an atherosclerotic change of the cerebral artery occurred in a way that carotid vascular resistence and cerebrovascular resistence were 'proportional'. Copyright Rapid Science Ltd

Journal Article↗

PubMed1998

PET study of striatal fluorodopa uptake and dopamine D2 receptor binding in a patient with juvenile parkinsonism.

We studied pre-synaptic and post-synaptic function in the striatum of a patient with juvenile parkinsonism (JP) using positron emission tomography (PET). [18F]6-fluorodopa (18FDOPA), 11C-YM-09151-2 and [18F]fluoro-2-deoxy-d-glucose (18FDG) were used to measure fluorodopa uptake, dopamine D2 receptor binding and glucose metabolism, respectively. In this patient, 18FDOPA accumulation was decreased markedly in the caudate nucleus and the putamen bilaterally. In the images of 11C-YM-09151-2 and 18FDG, in contrast, no conspicuous changes were observed in the striatum. Thus our PET studies using 18FDOPA, 11C-YM-09151-2 and 18FDG provide a useful approach for assisting the diagnosis of JP, because the present findings are different from the results in patients with dopa-responsive dystonia and hereditary progressive dystonia with marked diurnal fluctuation. Furthermore, our findings are of particular interest in relation to the pathogenesis of JP.Copyright Lippincott-Raven Publishers

Journal Article↗

PubMed1998

Subcellular distribution of tight junction-associated proteins (occludin, ZO-1, ZO-2) in rodent skin.

Occludin is an integral membrane protein that is concentrated at tight junctions (zonulae occludentes) in simple epithelial cells. ZO-1 and ZO-2 are peripheral membrane proteins that are localized at tight junctions in simple epithelial cells and at cadherin-based adherens junctions in nonepithelial cells. In this study, we investigated the expression and subcellular distribution of occludin, ZO-1, and ZO-2 in rodent skin. Immunoblotting detected all of these molecules in isolated epidermis, but the occludin/ZO-1 (or occludin/ZO-2) ratio was significantly lower than that in cultured simple epithelial cells. In the epidermis of adult skin, occludin was concentrated at cell-cell borders only in the most superficial zone of the granular cell layer, whereas ZO-1 and ZO-2 were distributed in a much broader zone from the spinous to the granular layers. During mouse skin development, this peculiar distribution of occludin in the epidermis appeared when the periderm, a simple epithelium bearing typical occludin-based tight junctions, was sloughed off at embryonic day 16.5 of gestation. Freeze-fracture electron microscopy identified the so-called focal strands or maculae occludentes, i.e., spot tight junction-like structures, between adjacent granular cells, and anti-occludin monoclonal antibody exclusively labeled these focal strands. In hair follicles, occludin and ZO-1 were colocalized at cell-cell borders in Henle's layer and the cornifying cuticle of the inner root sheath. In addition, ZO-1 but not occludin were localized weakly at the outer root sheath and intensely at the hair cortex/matrix.

Animals↗

PubMed1998

Purification of recombinant human pepsinogens and their application as immunoassay standards.

Human pepsinogen (PG) A and C were cloned in Escherichia coli, but the levels of expression were low and unstable. When there were fused to maltose-binding protein (MBP), the fusion proteins (MBP-PGA and MBP-PGC) were expressed as the major products. Although these fused products were almost totally recovered from the insoluble fraction, the renaturation and purification procedures were easy and simple. MBP-PGA and the PGA segment obtained by factor Xa digestion (designated as r-PGA) possessed proteolytic activities equivalent to native PGA purified from gastric tissue (t-PGA). For PGCs (MBP-PGC, r-PGC and t-PGC) also, the specific activities were almost the same. However, the activities of PGCs were about 3- to 4-hold higher than those of PGAs. In PGA and PGC immunoassay systems, r-PGs (r-PGA and r-PGC) and the EIA kit standard PGs (gastric mucosal PGs) exhibited a good correlation. From these results, r-PGs would seem to be applicable as assay standards without compromising the sensitivity of the immunoassay systems.

ATP-Binding Cassette Transporters↗

PubMed1998

Glycine-valine dimorphism at the 86th amino acid of HLA-DRB1 influenced the prognosis of postschistosomal hepatic fibrosis.

Chinese patients (n = 113) with schistosomal hepatic fibrosis diagnosed by ultrasonography (grade I, II, or III) and 184 age- and sex-matched persons with no clinical information of schistosomal infection were typed for their HLA-DRB1 alleles by DNA typing. There was no single allele that conferred susceptibility or resistance to fibrosis. However, there were three groups of alleles that showed decreased (resistant), increased (susceptible), or neutral frequency in the patients with fibrosis. The susceptible alleles, DRBI *1202, DRB1 *1404, and DRBI *1405, shared a valine at amino acid residue 86, whereas the resistant alleles, DRB1*11011, DRB1*0409, and DRB1*0701, all had glycine at position 86. Therefore, this study focused on the glycine-valine dimorphism at aa 86, which influences the depth of the P1 pocket in the antigen binding groove, and found that the 86th valine allele was significantly increased in the patients with fibrosis (odds ratio = 2.2; 95% CI = 1.34-3.61, corrected P < .05).

Alleles↗

PubMed1998

Effects of thyroid hormone on catecholamine and its metabolite concentrations in rat cardiac muscle and cerebral cortex.

Clinical and experimental data suggest that thyroid hormone affects the actions of catecholamine (CA). However, the serum or tissue levels of CA during thyroid disorders have not been well defined. Accordingly, we investigated the levels of CA and their metabolites in the cardiac muscle, the cerebral cortex, and the plasma of rats with hyperthyroidism and hypothyroidism versus euthyroid animals. The Neurochem analyzer system (ESA, Inc., Bedford, MA) was used in such determinations. The cardiac muscles of hyperthyroid rats exhibited a 16% decrease in the levels of 1-dopa, 3-methoxytyramine (3-MT) and homovanillic acid (HVA) as compared with those in euthyroid rats. The levels of norepinephrine (NE) in cardiac muscle of these rats increased significantly (5.2-fold) relative to the levels in euthyroid rats. NE was undetectable in the cardiac muscles of the hypothyroid rats. Epinephrine (E) and dopamine (DA) were not detected in the cardiac muscles of the rats with either thyroid disorder. Levels of E and 3,4-dihydroxymandelic acid (DOPEG) were detected only in the cerebral cortex of hyperthyroid rats. The cerebral cortex levels of 3-methyoxytyramine (3-MT), 3,4-dihydroxyphenylacetic acid (DOPAC), metanephrine (MN), and homovanillic acid (HVA) were all significantly increased in the hyperthyroid versus the euthyroid rats. The cerebral cortex levels of DA, NE, normetanephrine (NMN), and VMA in the hyperthyroid rats all showed a significant decrease. Levels of NE, NMN, and DOPAC in the cerebral cortex increased significantly in the hypothyroid rats. The level of VMA was undetectable in cerebral cortex of such animals. Data from studies on cardiac muscle and cerebral cortex indicate that the changes in CA and CA metabolites are responsible in part for the cardiovascular and the central nervous system symptoms observed in hyperthyroidism and hypothyroidism.

Animals↗

PubMed1998

Immunologic self-tolerance maintained by CD25+CD4+ naturally anergic and suppressive T cells: induction of autoimmune disease by breaking their anergic/suppressive state.

Elimination of CD25+ T cells, which constitute 5-10% of peripheral CD4+ T cells in normal naive mice, leads to spontaneous development of various autoimmune diseases. These immunoregulatory CD25+CD4+ T cells are naturally unresponsive (anergic) in vitro to TCR stimulation, and, upon stimulation, suppress proliferation of CD25-CD4+ T cells and CD8+ T cells. The antigen concentration required for stimulating CD25+CD4+ T cells to exert suppression is much lower than that required for stimulating CD25-CD4+ T cells to proliferate. The suppression, which results in reduced IL-2 production by CD25-CD4+ T cells, is dependent on cellular interactions on antigen-presenting cells (and not mediated by far-reaching or long-lasting humoral factors or apoptosis-inducing signals) and antigen non-specific in its effector phase. Addition of high doses of IL-2 or anti-CD28 antibody to the in vitro T cell stimulation culture not only breaks the anergic state of CD25+CD4+ T cells, but also abrogates their suppressive activity simultaneously. Importantly, the anergic/suppressive state of CD25+CD4+ T cells appeared to be their basal default condition, since removal of IL-2 or anti-CD28 antibody from the culture milieu allows them to revert to the original anergic/suppressive state. Furthermore, transfer of such anergy/suppression-broken T cells from normal mice produces various autoimmune diseases in syngeneic athymic nude mice. These results taken together indicate that one aspect of immunologic self-tolerance is maintained by this unique CD25+CD4+ naturally anergic/suppressive T cell population and its functional abnormality directly leads to the development of autoimmune disease.

Animals↗

PubMed1998

Vitamin E and coenzyme Q concentrations in the thyroid tissues of patients with various thyroid disorders.

To clarify the different roles of free radical scavenging systems in various thyroid disorders, we measured the levels of alpha-, beta-, and gamma-tocopherols and coenzyme Q in the thyroid tissues of patients with thyroid tumors and Graves' disease using high-performance liquid chromatography. The levels of alpha-tocopherols and gamma-tocopherols in the thyroid tissue of patients with papillary carcinoma and the level of gamma-tocopherol in the thyroid tissue of patients with malignant lymphoma were elevated compared with those in normal thyroid tissues. The level of coenzyme Q was reduced in the thyroid tissue of patients with Graves' disease and follicular and papillary thyroid carcinomas. These findings imply that vitamin E and coenzyme Q as scavengers play some role in thyroid follicular cell hyperfunction or dysfunction.

Graves Disease↗

PubMed1998

Expression of two glutamate transporters, GLAST and EAAT4, in the human cerebellum: their correlation in development and neonatal hypoxic-ischemic damage.

Normal development and hypoxic-ischemic changes of glutamate-aspartate transporters (GLAST) and excitatory amino acid transporter type 4 (EAAT4) were demonstrated in the human cerebellum. GLAST-immunoreactive Bergmann's glia and EAAT4-positive Purkinje cells showed a specific distribution and localization, and developed with age in the molecular and Purkinje cell layers. The dendrites and cell bodies of Purkinje cells, which showed EAAT4 immunoreactivity, were ensheathed by GLAST processes. In neonatal hypoxic-ischemic encephalopathy (HIE), GLAST immunoreactivity decreased in the molecular layer and increased in the inner granule cell layer at an early stage, and markedly increased in the Purkinje and inner granule cell layers at a late stage. EAAT4 immunoreactivity decreased with post-ischemic changes of Purkinje cells. GLAST reactivity changed more rapidly than EAAT4 in cases of HIE. These changes of GLAST and EAAT4 may be closely related to the vulnerability of Purkinje cells in hypoxia-ischemia. The glutamate transporter of Bergmann glia may play a more important role in the regulation of the extracellular glutamate concentration in hypoxia and/or ischemia.

ATP-Binding Cassette Transporters↗

PubMed1998

Polymorphism of the apolipoprotein E and angiotensin I converting enzyme genes in Japanese patients with myocardial infarction.

OBJECTIVE: To investigate the genetic contribution for myocardial infarction. METHODS: We investigated common polymorphisms of apolipoprotein E gene and angiotensin converting enzyme (ACE) gene in Japanese population. Subjects were 422 healthy people and 254 patients with myocardial infarction. We evaluated the 287 base pair (bp) insertion (I)/deletion (D) polymorphism in intron 16 of the ACE gene and a polymorphism in the apolipoprotein E gene by using the polymerase chain reaction. RESULTS: The ACE genotype prevalences for II, ID, and DD were 36.2, 46.1, and 17.7%, respectively, among the myocardial infarction patients. The prevalence of the D allele of the ACE gene among the myocardial infarction patients (0.593) exceeded that among the healthy controls (0.407). The prevalences of the epsilon 2, epsilon 3, and epsilon 4 alleles of the apolipoprotein E genotype among healthy controls were 0.024, 0.882, and 0.094, and those among survivors of myocardial infarction were 0.024, 0.834, and 0.142, respectively. Myocardial infarction patients had an excessive prevalence of the apolipoprotein E epsilon 4 allele (P < 0.05). Multiple regression analysis demonstrated that the independent risk factors for developing myocardial infarction were age, DD genotype of ACE gene, and apolipoprotein E epsilon 4 allele. Stenotic coronary vessels in myocardial infarction patients did not differ significantly among the patients with various ACE and apolipoprotein E genotypes in the present study. CONCLUSIONS: Among the Japanese, apolipoprotein E epsilon 4 carriers and subjects with ACE DD genotype are at an increased risk of myocardial infarction.

Aged↗

PubMed1998

Hepatitis G virus infection in patients with alcoholic liver disease.

The recently discovered hepatitis G virus (HGV) is believed to be a single-stranded RNA virus belonging to the Flaviviridae family, similar to hepatitis C virus (HCV), but much remains to be learned about its characteristics and clinical manifestations. Although it has been suggested that alcohol intake might have an effect on liver pathology by promoting the proliferation of HCV, the association between HGV infection and alcohol intake is yet to be elucidated. In the present study, we investigated the prevalence of HGV-RNA and HCV-RNA in 63 patients with alcoholic liver disease, and studied the effects of alcohol on the progression of hepatic damage in HGV-RNA positive patients. Among these 63 patients, 9 (14%) were HGV-RNA-positive and 37 (59%) were HCV-RNA-positive. Seven (78%) of the nine HGV-RNA positive patients were also infected with HCV. The patients showed no significant differences of clinical features in relation to the presence or absence of HGV infection. There were also no differences of liver histology among HCV-RNA-positive patients with or without HGV-RNA. The two patients infected with HGV alone had alcoholic hepatitis and nonspecific reactive hepatitis, respectively. In this study, alcohol seemed to have little influence on the progression of the liver histology in HGV-RNA-positive patients.

Adult↗

PubMed1998

Familial occurrence of congenital bile duct cysts.

Congenital bile duct cysts are now a well-documented anomaly of the biliary tree, and have become more common in Japan. Familial occurrence of congenital bile duct cysts, however, is extremely rare, with only six reported cases in the literature. We report a familial pattern of congenital bile duct cysts in a mother and her daughter. A 33-year-old female was admitted for evaluation of right upper quadrant abdominal pain and fever 6 days after an uneventful delivery of her second child. A computed tomography (CT) and ultrasound scan (US) revealed an obstructed biliary tract. Percutaneous transhepatic biliary drainage was then performed, and a cholangiogram revealed a Scholtz type B choledochocele without an anomalous connection of the pancreaticobiliary ducts. Endoscopic US demonstrated that the choledochocele was associated with a stone in the cyst. A pylorus-preserving pancreatoduodenal resection was performed, and a histological study revealed that the choledochocele was lined by biliary mucosa without evidence of malignancy. The newborn infant had an abdominal tumour. An US and CT revealed a congenital bile duct cyst. An operation was performed and the intraoperative cholangiogram showed an Alonso-Lej type I congenital bile duct cyst with an anomalous connection of the pancreaticobiliary ducts. Whether congenital bile duct cysts are hereditary remains to be elucidated.

Adult↗