Search PubMed⌕ Search

Biomedical subjects

T Maeda

Publications and source records attributed to T Maeda.

At least 703 records · Page 39Linked to original sources
PubMed1994

Genetic analysis of hydatidiform moles utilizing the oligonucleotide-DNA typing of the HLA-DRB gene.

The genetic origin of hydatidiform moles was analysed utilizing HLA-DNA typing. Using HLA-DR type-specific oligonucleotide probes, the DRB types of seven moles were determined and compared with the parental DRB types to determine the paternal and/or maternal origin of the moles. In four cases, the molar tissues showed single DRB types of paternal origin, although in one, the molar DRB type was also possessed by the mother. These four moles were, therefore, considered to be androgenetic in origin. Chromosomal karyotyping was carried out for three of these cases and confirmed the DR-DNA typing results. Two moles demonstrated a DRB-type triplet, which strongly suggested triploidy. Although one mole showed a heterozygous DRB type, karyotyping indicated triploidy (69, XXX) and suggested that this mole was caused by dispermy-fertilization, in which both of the sperms had the same DRB type. Although the majority (about 80%) of partial hydatidiform moles have been reported to be triploid as a result of dispermy, four of the moles analysed in this study (cases 1, 2, 3 and 4), diagnosed as partial macroscopically and/or histopathologically, were found to be androgenetic in origin using karyotyping and DR-DNA typing. Therefore, HLA-DR DNA typing, combined in some cases with karyotyping, provides an accurate method for diagnosing androgenesis and triploidy in complete and partial hydatidiform moles.

DNA Probes, HLA↗
PubMed1994

Plasma exchange and the arterial blood ketone body ratio in patients with acute hepatic failure.

Hepatocyte regeneration in acute hepatic failure is essential for recovery, but requires a large amount of energy. One problem with plasma exchange as supportive therapy in these cases is that massive citrate infusion has an adverse effect on the hepatic energy charge, which may be a serious risk in these patients. The ratio of acetoacetate to beta-hydroxybutyrate in arterial blood has been reported to reflect the cellular energy charge of hepatocytes. In this study, this ratio was assessed before and after plasma exchange in 19 patients with acute hepatic failure. Eight patients recovered and 11 died. The arterial blood ketone body ratio was below 0.6 in all 11 nonsurvivors. It fell to below 0.4 in 10 of them during the first plasma exchange session, and remained below 0.4 for over 12 h in seven of them. On the other hand, the arterial blood ketone body ratio returned to above 0.6 in four of eight surviving patients within 12 h after the first plasma exchange and remained below 0.4 for over 12 h only in two of eight patients. These data indicate that plasma exchange may cause suppression of the arterial ketone body ratio in patients with severe acute hepatic failure. These metabolic changes impair liver metabolism and may make effective hepatocyte regeneration impossible.

3-Hydroxybutyric Acid↗
PubMed1994

DNA typing of HLA class II genes; DRB1*0803 increases the susceptibility of Japanese to primary biliary cirrhosis.

The association between human leukocyte antigens and primary biliary cirrhosis is controversial, but major histocompatibility complex class II antigen DR8 was recently reported to be associated with increased susceptibility for primary biliary cirrhosis in some Caucasians and Japanese. Accordingly, we performed DNA typing of HLA class II genes in Japanese patients with primary biliary cirrhosis. The genotypes of HLA DRB1, DRB3-5, DQA and DQB were determined by polymerase chain reaction and subsequent hybridization with sequence specific oligonucleotides in 31 primary biliary cirrhosis patients and 215 racially matched local controls. DR8 was found in 24 of the 31 primary biliary cirrhosis patients and was highly concentrated in DRB1*0803. The gene frequency of DRB1*0803 was significantly increased in the patients (35.5% vs 7.4%, relative risk = 6.84, p < 0.0001). DQA1*0103 and DQB1*0601 were also increased in the primary biliary cirrhosis patients, in relation to linkage disequilibrium with DRB1*0803 on the same haplotype. In contrast, DQA1*0102 showed a significantly lower frequency in the primary biliary cirrhosis patients (p < 0.05). These data suggest that DRB1*0803 is one of the HLA class II genes related to an increased risk of primary biliary cirrhosis in Japanese individuals.

Adult↗
PubMed1994

Prevention of insulitis and diabetes in beta 2-microglobulin-deficient non-obese diabetic mice.

beta 2-Microglobulin (beta 2m)-deficient non-obese diabetic (NOD) mice were established by crossing beta 2m-deficient 129/Sv mice with NOD mice, and used to examine the possible involvement of MHC class I molecules and CD8+ T cells in the development of insulitis and diabetes. In these mice, MHC class I molecules were not expressed, resulting in no generation of CD8+ T cells. None of eight lines of beta 2m-deficient NOD mice (-/-) established developed overt diabetes by 32 weeks, while control littermates (+/+) became diabetic by 22 weeks. histological studies showed no significant lymphocyte infiltration of the islets (insulitis score: 0.03 +/- 0.03) in any of the beta 2m-deficient NOD mice (-/-) compared with littermate NOD mice (+/+) with overt insulitis (1.42 +/- 0.28). These findings support the notion that the expression of MHC class I molecules and/or CD8+ T cells plays an essential role in the infiltration of CD4+ T cells in islets as well as the development of diabetes in NOD mice.

Animals↗
PubMed1994

Inhibition of the renal excretion of tazobactam by piperacillin.

A 1:4 by weight of combination of tazobactam, a new beta-lactamase inhibitor, and piperacillin, is now under development in Japan. After bolus iv administration of the combination to beagle dogs, piperacillin both significantly raised the area under plasma concentration time curve (AUC0 approximately infinity) and significantly decreased the total body clearance (Cltot) of tazobactam. The percentage binding of tazobactam and piperacillin to dog and human serum protein was the same for the combination as for the individual compounds. Piperacillin significantly decreased the renal clearance (Clr) and the clearance ratio (Cr) of tazobactam in dogs. Further, probenecid significantly decreased Clr of both tazobactam and piperacillin, and the Cr of tazobactam and piperacillin approximately reached unity. These results indicate that piperacillin inhibits the renal excretion of tazobactam. Both tazobactam and piperacillin are secreted by a tubular anion transport system which is identical to the probenecid secretion system.

Animals↗
PubMed1994

Cell-adhesive activity and receptor-binding specificity of the laminin-derived YIGSR sequence grafted onto Staphylococcal protein A.

Laminin contains multiple oligopeptide motifs to promote cell adhesion and migration. One of these motifs is YIGSR within the B1 chain. We reconstituted the cell-adhesive activity of YIGSR motif by grafting it onto a truncated form of the Staphylococcal protein A (designated tSPA) via cassette mutagenesis. When coated on a polystyrene surface, the YIGSR-grafted tSPA (YIGSR-tSPA) promoted attachment and spreading of mouse melanoma and human rhabdomyosarcoma cells, but not of hamster fibroblasts. The cell-adhesive activity of YIGSR-tSPA was abolished by amino acid substitution or scrambling of the inserted YIGSR sequence. Divalent cations Mn2+ and Mg2+, but not Ca2+, promoted the cell adhesion to YIGSR-tSPA. Interestingly, the YIGSR-tSPA-mediated cell adhesion was barely inhibited by the linear peptide CDPGYIGSR-NH2, but was strongly inhibited by the cyclic peptide CDPGYIGSRC and another peptide PEILDVPST, which is a specific inhibitor for integrin alpha 4 beta 1. Among various anti-integrin antibodies, anti-alpha 4 and anti-beta 1 antibodies specifically inhibited the cell adhesion to YIGSR-tSPA. In support of these observations, adhesion of rhabdomyosarcoma cells to intact laminin was also partially inhibited by synthetic PEILDVPST peptide and anti-alpha 4 antibody. These results, taken together, indicate that the YIGSR motif exerts its cell-adhesive activity through interaction with integrin alpha 4 beta 1.

Amino Acid Sequence↗
PubMed1994

HLA-DR alleles in patients with Sjögren's syndrome over-representing V beta 2 and V beta 13 genes in the labial salivary glands.

To identify genetic factors that play a role in the pathogenesis of patients with SS over-representing V beta 2 and V beta 13 genes in the lips, HLA-DR and -DQ alleles of 10 primary SS patients with predominant expression of V beta 2 and V beta 13 genes in the lips were analysed, using the polymerase chain reaction (PCR) and sequence specific oligonucleotide probes. The CDR3 amino acid sequences of cDNA clones encoding V beta 2 and V beta 13 genes were also determined by PCR. The results showed that the DRB4*0101 allele was significantly increased (80%) and that the frequency of DRB3 allele was decreased (0%) when compared to findings in healthy subjects (35.6 and 26%, respectively). Sequencing analyses demonstrated that 75% of V beta 2 cDNA clones and 87% of V beta 13 cDNA clones had a glutamine residue at position 106, in the CDR13 region. Moreover, the conserved sequences (Y*TLRNEQ) in the CDR3 of V beta 13-positive T cell were detected in two different clones (27%) from the two individual SS patients. These findings suggest that the decreased DRB3 and increased DRB4*0101 alleles may be associated with the antigens recognized by V beta 2- and V beta 13-positive T cells.

Alleles↗
PubMed1994

Severe neurological abnormalities associated with a mutation in the zinc-finger domain in a group A xeroderma pigmentosum patient.

All the reported Japanese patients with group A xeroderma pigmentosum (XP) have two or three mutations at codon 116 in exon 3, codon 228 in exon 6, and the splicing acceptor site of intron 3 of XP group A complementing (XPAC) gene. A homozygote (XP39OS) with a nonsense mutation at codon 228 has less severe neurological abnormalities than patients with the splicing mutation at the acceptor site of intron 3. As homozygotes for the nonsense mutation at codon 116, which truncates a carboxyl-terminal site of XPAC protein at an early part of its zinc-finger domain, have not been reported previously, the possible severity of associated neurological abnormalities was not known. We report a group A XP patient, XP18OS, who had neurological abnormalities which were more severe than those in patients homozygous for the splicing mutation. The polymerase chain reaction product from exon 3 of the patient's XPAC gene was digested completely into three fragments by MseI restriction endonuclease. Thus, the patient was homozygous for the mutation at codon 116.

Base Sequence↗
PubMed1994

Established IL-2-dependent double-negative (CD4- CD8-) TCR alpha beta/CD3+ ATL cells: induction of CD4 expression.

We established IL-2-dependent T cells from an adult T-cell leukaemia (ATL) patient whose leukaemic cells changed from CD4 single-positive in the initial phase to double-negative (CD4- CD8-) at the time of exacerbation. The cells termed SO-4 were of ATL cell origin and showed the double-negative TCR alpha beta/CD3+ T-cell phenotype. SO-4 cells acquired CD4 antigen expression following stimulation with concanavalin A (ConA) or immobilized anti-CD3 antibody. The induction was inhibited by herbimycin A, an inhibitor of protein tyrosine kinase (PTK) activity. No CD4 mRNA was detectable in unstimulated SO-4 cells but a 3.0 kb signal specific for CD4 mRNA was detected after stimulation. These findings indicate that SO-4 cells return to their original phenotype (CD4 single-positive) by stimulation involving PTK. The results indicate that there is a pathway of phenotypic cycling between CD4 single-positive and double-negative T cells.

Benzoquinones↗
PubMed1994

Neonatal capsaicin pretreatment suppresses intramedullary inflammation in adjuvant-induced spondylitis.

In order to investigate the proposed involvement of neuropeptides in musculoskeletal inflammation we pretreated rats, in an adjuvant spondylitis model, with capsaicin, a neurotoxin. Immunohistochemistry showed that administration of capsaicin to newborn rats depleted irreversibly the neuropeptide, substance P. Elimination of capsaicin-sensitive fibres by the neonatal injection of capsaicin did not suppress the peridiscitis of rats in which adjuvant spondylitis was induced at 7 weeks of age. However, elimination of capsaicin-sensitive fibres did suppress the inflammation usually seen in the bone marrow. We speculate that this intramedullary inflammation is normally induced or sustained by capsaicin-sensitive fibres.

Animals↗
PubMed1994

High-density proteoglycan induces specific suppression of adjuvant-induced arthritis in rats.

In vitro data support the view that T cells in adjuvant-induced arthritis (AIA) respond to the proteoglycan (PG) component of articular cartilage; however, an in vivo role for PG in AIA has yet to be shown. To do so, we examined the effects of pretreatment with bovine cartilage high density PG (HDPG) on AIA induced by heat-killed Mycobacterium butyricum in Lewis rats. Purified bovine cartilage HDPG emulsified in Freund's incomplete adjuvant (FIA) was injected intradermally into rats 7 days before challenge with Myco. butyricum. The severity of arthritis was significantly suppressed in rats pretreated with as little as 0.75 mg of HDPG, and the arthritis was completely suppressed in rats pretreated with 3.0 mg of HDPG. This suppression was specific, as the same treatment did not protect against type II collagen-induced arthritis. Suppression of AIA is primarily a property of the HDPG, as suppression of the arthritis was significantly less with pretreatment with 3.0 mg of middle density fractions of PG, and no suppression was observed with pretreatment with the lowest density fraction of PG. Thus we report that pretreatment with cartilage HDPG, but not lower density PG, can induce specific suppression of AIA. These in vivo results support the view that immunity to cartilage HDPG plays a major role in the pathogenesis of AIA, and can induce specific tolerance to this type of arthritis.

Animals↗
PubMed1994

Morphological analysis of ileal grafting following ileocystoplasty in the rat: a kinetic and ultrastructural study of the intestinal epithelium.

Ileocystoplasty was performed in rats and the morphological and cell-kinetic changes occurring in the ileal grafts were determined at intervals up to 18 months postoperatively. The intestinal mucosa underwent no progressive changes but included villous and avillous regions associated with crypts of various sizes at all time intervals. Newly appearing and densely packed epithelial cells, shaped like petals, were always present in the lower parts of the villi associated with crypts showing no elongation, but seldom present in those with elongated crypts in the villous mucosa. Bromodeoxyuridine studies showed that the petal-shaped cells interfered with cell migration. No petal-shaped cells were observed in avillous mucosa in which the rate of cell turnover depended on crypt size. Fine-structural changes in absorptive epithelial cells in both types of mucosa included features of prematurity or hypermaturity in the cytoplasm and close adherence to the basal portions of adjacent cells and to the basal lamina. These changes may possibly contribute to the prevention of reabsorption of urine. However, some of the mechanisms responsible for adherence of the basal parts might incidentally interfere with the normal cell kinetics of the intestinal epithelium, resulting in dense packing of cells and the formation of multiple types of mucosa in ileal grafts.

Animals↗
PubMed1994

The arterial blood ketone body ratio as a possible marker of multi-organ failure in patients with alcoholic hepatitis.

The arterial blood ketone body ratio (AKBR: acetoacetate/3-hydroxybutyrate) within 48 h of admission is reported to be an excellent prognostic indicator for acute hepatic failure. In this study, we assessed the AKBR in 63 patients receiving supportive medical therapy for alcoholic hepatitis, in order to investigate its efficacy for predicting complications and the prognosis. Twelve patients (19%) died and 51 patients (81%) survived. Hepatic encephalopathy, severe coagulopathy, and renal failure were the critical complications (P < 0.01), and the AKBR at 72 h of hospitalization was closely correlated with these complications (P < 0.01), although they could not be predicted in any other way during the early admission period. The AKBR of normal individuals ranged from 1.0 to 2.1 (1.54 +/- 0.26, mean +/- SD), so an AKBR > 1.0 (mean-2SD) was defined as normal. The AKBR value at 48 and 72 h of hospitalization showed a significant difference between survivors and non-survivors (P < 0.01). All survivors showed an increase of the AKBR to above 0.7 at 72 h, with subsequent maintenance of the ratio over 1.0, while eight of the 12 non-survivors had sustained suppression of the AKBR below 0.7 at 72 h. Seven of these eight patients subsequently developed multiple organ failure. These findings suggest that the AKBR could be a possible marker of potentially fatal complications and a poor prognosis in patients with alcoholic hepatitis.

Acetoacetates↗
PubMed1994

Evidence for the existence of intraepithelial nerve endings in the junctional epithelium of rat molars: an immunohistochemical study using protein gene product 9.5 (PGP 9.5) antibody.

Innervation of the junctional epithelium was investigated in rat molars by means of immunohistochemistry for protein gene product 9.5 (PGP 9.5) at light and electron microscopic levels. In comparison with our previous study on same tissues using neurofilament protein (NFP)-antibody, the PGP 9.5-immunostaining further disclosed numerous nerve fibers in the gingiva of rat molars and revealed the existence of a well-developed plexus of PGP 9.5-positive nerve fibers. The interproximal portion also contained numerous nerve fibers. Observation of horizontal sections revealed a denser innervation toward the inner junctional gingival epithelium than the outer marginal epithelium. The nerve fibers, beaded in appearance and extending from the nerve bundles in the lamina propria, penetrated into the junctional epithelial layer and were distributed throughout the junctional epithelium, with some nerves being located near the epithelial surface. Non-neuronal cells showing PGP 9.5-immunoreactivity were absent in the junctional epithelium. In immunoelectron microscopy, the axoplasm of nerves in the gingiva was filled with electron-dense reaction products of PGP 9.5, except for the cell organellae. The nerve fibers were devoid of Schwann cell investment and terminated among the epithelial cells in the junctional epithelium, frequently beneath the epithelial surface. The intraepithelial nerve endings contained various kinds of vesicles including large-cored ones, supporting the presence of peptidergic innervation shown by previous studies. These findings confirmed the usefulness of PGP 9.5-immunohistochemistry for the identification of delicated nerve fibers in dental tissue, and suggested the dense network of nerve fibers that may serve as sensory receptor and other functions in the junctional epithelium.

Animals↗
PubMed1994

Silent cerebral infarction associated with coronary artery disease.

To investigate the relationship of coronary artery disease and silent cerebral infarction, 50 patients who underwent coronary arteriography and cranial magnetic resonance imaging were studied. The patients were divided into three groups. The incidence of silent cerebral infarction (chiefly lacunar infarction) was significantly higher in patients with old myocardial infarction and in those with angina pectoris than in the control group (80, 78 and 29%, respectively, p < 0.05). Silent cerebral infarction is considered to be a risk factor for symptomatic cerebrovascular disease, so more attention should be focussed on the prevention of stroke in patients with coronary artery disease.

Aged↗
PubMed1994

Mast cells alter granular properties and spatial relation to nerve fibres in spondylitis of adjuvant-treated rats.

It has been long implicated that mast cells (MCs) have a close spatial relationship to the peripheral nerve fibres. In the present study, which used spondylitis of adjuvant-treated rats, we investigated the behaviour of MCs in relation to peripheral nerve fibres and other inflammatory cells. Rat MCs with staining properties like connective tissue MCs decreased in number as inflammation progressed. With additional electron microscopic studies it was possible to observe the sequence of changes in their granular ultrastructure during active inflammation. Thus, the decrement of MCs with staining properties like connective tissue MCs was attributable to the changes in their granular conformation. In contrast, enzyme histochemistry of nerve fibres indicated that the percentages of MCs which were distant from nerve fibres increased significantly during the early stage of inflammation (p < 0.01). We speculate that while other inflammatory cells infiltrate, MCs deviate actively form nerve fibres and release their granular content.

Animals↗
PubMed1994

Transient expression of [D-Ala2] deltorphin I-like immunoreactivity in prenatal rat small intestine.

We studied the distribution of immunoreactive elements for [D-Ala2] deltorphin I (DADTI), a delta-opioid receptor ligand, in fetal and postnatal rat small intestine. DADTI-like immunoreactive cells were detected transiently on embryonic Days 20 and 21. Electron microscopic examination revealed that positive staining occurred in mucous epithelial cells, either mature goblet cells or undifferentiated cells containing only a few mucous granules. Positive immunoreaction products in mature goblet cells were confined in their apical cytoplasm to the luminal parts of mucous granule aggregates. The result suggests that a DADTI-like molecule(s) is synthesized in rat intestinal goblet cells and is secreted in a diacrine fashion into the intestinal lumen at a late fetal period. The molecule(s) thus secreted may be important for the intestine of rats just before birth, because DADTI-like immunopositive goblet cells are no longer seen at any postnatal period.

Amino Acid Sequence↗