Search PubMed⌕ Search

Biomedical subjects

T Maeda

Publications and source records attributed to T Maeda.

At least 613 records · Page 34Linked to original sources
PubMed1995

Neurochemical heterogeneity of the primate nucleus accumbens.

In order to further investigate the neurochemical anatomy of the primate nucleus accumbens (NAC), the distributions of the neuropeptides leucine-enkephalin (Leu-ENK), neurotensin (NT), and substance P (SP) and of haloperidol-induced c-fos expression were investigated in the macaque monkey using immunohistochemical methods. To define the boundaries of the NAC, dopamine (DA) and tyrosine hydroxylase (TH) immunohistochemistry was performed. In addition, to formulate the distinction between subdivisions of the nucleus accumbens, immunohistochemistry for calbindin-D28 (CBD) and SP was employed. In general, the medial part of NAC, which consisted of small to medium-sized cells, was low for CBD immunoreactivity and moderate to high for SP immunoreactivities, while the dorsolateral part, which was composed of small cells, showed the opposite pattern of immunostaining for CBD and SP. Many Leu-ENK-immunoreactive perikarya were observed in the dorsal NAC at its middle and caudal levels. There were moderate densities of Leu-ENK-positive fibers throughout the medial part of the NAC. At the dorsolateral margin of the NAC, Leu-ENK-positive fibers formed patches. Most NT-positive perikarya were found in the dorsolateral subdivision. SP-positive perikarya were scarce in the NAC. Dense distribution of NT- and SP-containing fibers or puncta were observed in the mediodorsal part (medial subdivision), where a dense field of DA-immunoreactive fibers was observed. The ventral part (ventral subdivision) contained moderate numbers of NT- and SP-immunoreactive fibers. Haloperidol-induced c-fos expression was very extensive in the medial half of NAC, particularly in the mediodorsal region, which overlapped with the DA- and peptide-rich region. The present study indicates that the NAC of the primate can be subdivided into at least three subterritories, the dorsolateral, medial and ventral subdivision, by neuropeptide histochemistry as well as by the response of its constituent neurons to haloperidol.

Animals↗
PubMed1995

Auxiliary heterotopic partial liver transplantation in pigs with acute liver failure.

Fulminant hepatic failure is usually fatal without liver transplantation; however, orthotopic liver transportation is often difficult to perform due to the high risk of coagulopathy and the development of multiple organ failure. Auxiliary heterotopic partial liver transplantation (APLT), However, has the potential to provide an effective hepatic support system considering that the host liver is left in situ and the surgical procedure is less invasive. In this report, we describe the beneficial effects of performing 60% APLT on the hepatic function and survival of pigs with acute hepatic failure induced by hepatic artery ligation. The pigs were divided into a control group of nine animals (group 1) that had portal vein and hepatic artery ligation with a side-to-side portacaval shunt, and an APLT group of seven animals (group 2) that had portal vein and hepatic artery ligation with APLT. The two left lateral lobes of the donor liver were resected, reducing the liver weight to about 60%, and the graft was placed in the right subhepatic space. No deaths occurred intraoperatively. In group 1, eight pigs died of massive liver necrosis within 48 h and one died between 48 and 72 h (median survival 23 h). In group 2, two pigs died within 72 h due to preservation or anesthetic problems, but five survived for more than 3 days (median survival 13.4 days), with a significant difference between the two groups (P < 0.05). One animal was killed 30 days after APLT and excellent graft function was demonstrated by the synthesis of clotting factors, ammonia detoxification, and glucohomeostasis. Moreover, evidence of hepatic regeneration was found in the transplanted livers.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Dynamics of secretory granules in somatotrophs of rats after stimulation with growth hormone-releasing factor: a stereological analysis.

The anterior pituitary tissue of male rats injected with growth hormone-releasing factor (GRF) was either processed for stereology at the light- and electron-microscopic levels, or homogenized for growth hormone (GH) assay 2-60 min after GRF injection. Secretory granules of somatotrophs became smaller but increased in numerical density 2 min after GRF injection. Their volume density began to increase at 5 min. The frequency of exocytosis of the granules was most prominent as early as 2 min after GRF injection and reduced thereafter. GH levels in the tissue were lowest at 2-5 min, and returned to the control value by 60 min. Serum GH levels were highest at 15 min; even at 60 min, this value was higher than in the controls. These findings suggest that secretory granules in somatotrophs are stimulated to divide by GRF, resulting in a decrease in size and an increase in number. The discrepancy between the earlier formation of new secretory granules and the later restoration of intracellular GH levels implies that GRF first stimulates the synthesis of constituents of granules other than GH, and only later the synthesis of GH, and that newly formed small secretory granules contain less GH. From the clearance rate of serum GH and the frequency of granule exocytosis, it can be estimated that about a half million granules are released to maintain 1 ng/ml of serum GH in rats.

Animals↗
PubMed1995

Exacerbation of primary biliary cirrhosis during interferon-alpha 2b therapy for chronic active hepatitis C.

A 60-year-old woman with chronic active hepatitis C was treated with 6 million units of rIFN-alpha 2b daily for two weeks and subsequently three times weekly for several months. Histological examination proved a severe form of chronic active hepatitis C unexpectedly complicated with primary biliary cirrhosis (PBC). Before treatment, levels of serum alkaline phosphatase (ALP) or gammaglutamyltranspeptidase (GGT) had remained within normal limits over six months, although anti-mitochondrial antibody (AMA) was shown to be positive. After eight weeks of therapy, the daily dose of rIFN was reduced to 3 million units because of a marked increase of ALP and GGT, although the serum alanine aminotransferase (ALT) was normalized. Four months later, IFN treatment was suspended because of continuous elevation of the ALP and GGT levels, and administration of ursodeoxycholic acid was substituted. Two months later, the ALP and GGT levels returned to the normal range, although ALT was not normalized and HCV-RNA remained positive. This is the first report case that demonstrates IFN treatment potentially exacerbates PBC associated with chronic active hepatitis C. It is important for treating physicians to keep this association in mind.

Biopsy↗
PubMed1995

Interleukin-6 stimulates cell proliferation of rat pituitary clonal cell lines in vitro.

We investigated the effect of recombinant human IL-6 (rhIL-6) on cell proliferation using the MtT/E rat pituitary tumor cell line, which was recently established by Inoue et al. This cell line expresses the homeodomain protein Pit-1/GHF 1 and does not produce any significant amount of pituitary hormones, but retains its tumorigenicity by back-transplantation into rats, resulting in production of prolactin. MtT/E cells were seeded into Falcon 24-well plates at a density of 2 x 10(4) cells/well in a cultured medium, containing 10% horse serum and 2.5% fetal bovine, with test drug. After four-days (12 days for the time-course study) incubations, the cells were counted using a hemocytometer. Incubation for 4 days with rhIL-6 caused concentration-dependent stimulation of MtT/E cell growth and [3H]-thymidine incorporation into MtT/E cells. Addition of 20 ng/ml rhIL-6 to the culture medium stimulated MtT/E cell growth in a time-dependent manner, withdrawal of rhIL-6 from the culture medium reduced MtT/E cell growth, and re-addition of rhIL-6 to the culture medium again stimulated MtT/E cell growth. Among the cytokines tested, granulocyte colony-stimulating factor (rh G-CSF) also showed a slight but significant mitogenic activity on the MtT/E cells. Analysis of 125I-rhIL-6 binding to the MtT/E cells indicated a dissociation constant of 0.953 x 10(-9) mmol/l and the presence of 968 binding sites per cell.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Risk factors for intrahepatic recurrence in human small hepatocellular carcinoma.

BACKGROUND/AIMS: Postoperative intrahepatic recurrence of human hepatocellular carcinoma is high. Recently, the relationship between proliferating cell activity in the cirrhotic liver and occurrence or recurrence of hepatocellular carcinoma has been reported. METHODS: One hundred two resected cases of small hepatocellular carcinoma of < 3 cm in diameter without venous invasion or intrahepatic metastasis were examined to ascertain the factors affecting postoperative intrahepatic recurrence. RESULTS: Cumulative intrahepatic recurrence rates at 1, 3, and 5 years after surgery were 12.0%, 57.2%, and 67.6%, respectively. The log-rank test indicated that serum albumin levels of < 3.7 g/dL, alanine aminotransferase levels of more than 54 IU/L, active inflammation in the nontumorous portion, and high proliferating cell nuclear antigen labeling index in the nontumorous portion (> 23.2%) were significant risk factors for recurrence. Tumor factors, including tumor size, histological grade, or alpha-fetoprotein level, were not significant risk factors. Cox's proportional hazard model identified that serum albumin level and alanine aminotransferase level were independently associated with intrahepatic recurrence after hepatectomy. CONCLUSIONS: This study suggests that the principal cause linked to either a recurrence or a second new growth of hepatocellular carcinoma in the remnant liver after hepatectomy was the state of the underlying liver parenchyma as well as other tumor factors per se.

Adult↗
PubMed1995

Combined hepatocellular and cholangiocarcinoma: proposed criteria according to cytokeratin expression and analysis of clinicopathologic features.

We herein evaluated 36 cases of combined hepatocellular and cholangiocarcinoma (cHCC-CC) (including 29 surgically resected and seven autopsy cases) by the immunohistochemical methods of anticytokeratin antibodies 7 and 19, and then analyzed the clinicopathologic features by comparing cHCC-CC with ordinary hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC). The results indicated that even if mucin production could not be confirmed, nine cases with HCC areas that showed a histological resemblance to CC also showed immunohistological biliary differentiation. Therefore, we advocate that these HCC with biliary differentiation based on an immunohistochemical analysis should thus be included in the criteria of cHCC-CC in broad terms. Regardless of the extent of mucin production, the cHCC-CCs as indicated by an immunohistochemical analysis are considered to have a similar background to that of ordinary HCCs regarding such factors as the average age, male:female ratio, hepatitis B surface antigen (HBsAg) and hepatitis C virus antibody (HCVAb) positivity, alpha-fetoprotein level, and the presence of cirrhosis. However, cHCC-CCs tend to metastasize to many organs and the lymph nodes, and, as a result, have a poor prognosis.

Bile Duct Neoplasms↗
PubMed1995

Heterogeneity, polyploidy, aneusomy, and 9p deletion in human glioblastoma multiforme.

The short arm of chromosome 9 is frequently deleted in malignant gliomas. We used locus-specific probes for interferon-A (IFNA) and D9S3 in combination with a chromosome 9 centromeric probe to detect genetic aberrations on a cell-by-cell basis in touch preparations of 30 glioblastomas by fluorescence in situ hybridization. Seven (23%) of 30 tumors had deletions in > 70% of cells; the IFNA locus was deleted in all seven, but the D9S3 locus was deleted in only five of the seven. The latter data confirm that a tumor suppressor gene on 9p relevant to glioblastoma multiforme lies between D9S3 and IFNA. Eleven tumors had deletions in 20-40% of cells, more than three standard deviations above the level in control tissues. The remaining tumors had deletions in < 20% of cells. The seven tumors with the lowest percentage of deleted cells each had more than one genetically abnormal population of cells. In total, 10 cases were of this type (i.e., aneusomic for chromosome 9). Three of these 10 tumors had hybridization patterns consistent with polyploidy.

Adult↗
PubMed1995

T cell autoreactivity against a 28 kD biliary protein (B1-p28) in primary biliary cirrhosis.

BACKGROUND/AIMS: Cellular immune responses against biliary epithelial cells are important in understanding the pathogenesis of primary biliary cirrhosis. We previously reported a biliary antigen B1 which stimulated peripheral T lymphocytes of primary biliary cirrhosis as a possible, non-mitochondrial target of biliary epithelial cells. Further characterization of B1 was performed. METHODS: To confirm localization of B1 in biliary epithelial cells, a mouse monoclonal antibody was raised against B1. As B1 could be separated into two main components by SDS-PAGE under reducing condition, these components were individually cut out from Western blots and converted into antigen-bearing particles for a proliferation assay to detect the antigenic component responsible for stimulating lymphocytes. The relation of this proliferation to HLA DR antigens was also analyzed. RESULTS: Immunohistochemically, B1 was shown to be specifically expressed on biliary epithelial cells of human liver tissue. Of two components from B1 under reducing condition, prominent proliferation against B1-p28, a 28 kD component of B1 was detected in primary biliary cirrhosis. The reactivities were significantly higher than chronic liver diseases (p < 0.001) or normal controls (p < 0.001). Furthermore, high responders to B1-p28 were observed frequently in primary biliary cirrhosis patients with HLA DR8 (p < 0.02), which was susceptible to the development of primary biliary cirrhosis. CONCLUSIONS: These data suggest B1-p28 expressed on biliary epithelial cells is a candidate for the target antigen of primary biliary cirrhosis in addition to mitochondrial autoantigens. Further characterization of B1-p28 may provide new insight into the autoimmune mechanisms of primary biliary cirrhosis.

Aged↗
PubMed1995

Autoantibody against 70 kD heat shock protein in patients with autoimmune liver diseases.

BACKGROUND/AIMS: It has recently been suggested that heat shock proteins are implicated in the pathogenesis and teh pathophysiology of various immunological disorders, and the presence of antibodies against heat shock proteins has been reported in several autoimmune diseases. METHODS: We investigated autoantibodies against the two major human heat shock proteins (hsp70 and hsp90) in sera from patients with primary biliary cirrhosis and autoimmune hepatitis, the two major autoimmune liver disease. Reactivity with human heat shock proteins obtained from phytohemagglutinin stimulated cells was investigated by immunoblots with sera at 1:20 dilution. RESULTS: Reactivity with human hsp90 was not found in any sera from patients or normal controls. In contrast, reactivity with human hsp70 was found in 16 of 35 (45.7%) primary biliary cirrhosis patients and in 9 of 17 (52.9%) autoimmune hepatitis patients, but similar reactivity was found in only 2 of 15 patients with chronic hepatitis B and 1 of 13 patients with chronic hepatitis C. All the normal controls showed a negative reaction. Two-dimensional immunoblots and immunoabsorption experiments established that the autoantibody recognized only human hsc70 (73 kD/pI 5.5), a constitutive form of the hsp70 family. CONCLUSIONS: Although the pathological significance of the autoantibody against hsc70 in these autoimmune liver diseases remains unknown, the serum autoantibody detected in primary biliary cirrhosis patients is closely related to clinical variables including serum total bilirubin, alanine aminotransferase, IgG, IgM, titers of antimitochondrial antibodies, and major symptoms (pruritus and/or icterus). These observations may suggest that the anti-hsc70 antibody is an indicator for the disease activity of primary biliary cirrhosis.

Aged↗
PubMed1995

Comparative study of the mammalian liver innervation: an immunohistochemical study of protein gene product 9.5, dopamine beta-hydroxylase and tyrosine hydroxylase.

The liver innervation of eight different mammalian species was examined by immunohistochemical localization of protein gene product (PGP) 9.5 to visualize the general innervation for autonomic nerve fibres. In addition, dopamine beta-hydroxylase (DBH) and tyrosine hydroxylase (TH), two enzymes involved in catecholamine synthesis, were localized immunohistochemically to delineate hepatic sympathetic nerve fibres. We found that: (1) Within the interlobular region of each species, PGP 9.5, DBH and TH-positive nerve fibres were all seen in close association with branches of hepatic arteries, portal veins and bile ducts. (2) Within the parenchyma of the guinea-pig, cat, dog, pig, monkey and human liver, the presence of the three immuno-positive nerve fibres could be unequivocally identified, although the density of these intralobular fibres showed marked species variation. Moreover, immunoelectron microscopic study confirmed that PGP 9.5-positive nerve terminals of the human liver are in close apposition to hepatocytes. (3) In mouse and rat, no parenchymal nerve fibres immunoreactive for PGP 9.5, TH or DBH could be demonstrated.

Adult↗
PubMed1995

Patch sensor detection of glutamate release evoked by a single electrical shock.

We tried to detect minimal stimulation-induced glutamate overflow from the surface of a hippocampal slice using an outside-out patch electrode excised from pyramidal cell membranes. The amplitude of the stimulation-induced patch current was dependent on the distance between the slice surface and the tip of patch sensor. The current-voltage relations of the stimulation-induced patch current were similar to those of the current evoked puff by application of L-glutamate to the patch. This indicates that the stimulation-induced patch current was produced by glutamate released from presynaptic terminals, and thus this technique may be useful in the study of transmitter release evoked by minimal electrical stimulation in brain slices.

Action Potentials↗
PubMed1995

The induction of skin xenograft tolerance in rat-to-mouse combination could be affected by DFR mediating cells and antibodies against rat bone marrow cells as well as NK cells in the cyclophosphamide-induced tolerance system.

We investigated whether the prolongation of skin xenograft survival was obtained by a tolerance-inducing method using cyclophosphamide (CY), by which long-lasting skin allograft tolerance could be induced. The long-lasting skin allograft survival could be obtained in the recipient C3H/HeN (C3H) mice which were given 100 micrograms of anti-CD4 mAb on day -3, 1 x 10(8) spleen cells (SC) plus 3 x 10(7) bone marrow cells (BMC) derived from C57BL/6 (B6) mice on day -2,200 mg/kg CY on day 0, and which were grafted with allogeneic B6 skin on day 14. When the C3H mice were treated with anti-CD4 mAb, 1 x 10(8) s.c. plus 5 x 10(7) BMC derived from F344 rat and CY, the F344 skin grafts survived slightly longer (about 15 days) than those in untreated recipients (about 8.4 days). Such a prolongation of skin xenograft survival was considered donor-specific because rejection of 3rd party skin grafts from BN rats occurred significantly earlier than that of F344 skin grafts. In the recipient C3H mice treated with anti-CD4 mAb, F344 s.c. plus BMC and CY, mixed chimerism in the periphery was detected for a few days after CY administration, although intrathymic chimerism was not detected throughout this study. In these recipient C3H mice, cytotoxic T lymphocytes (CTL) against F344 antigens were completely abrogated through the delayed footpad reaction (DFR) remained at a low but significant level. Moreover, though antibody (Ab) activity against F344 s.c. was completely abrogated, neither Ab activity against F344 BMC, which seemed to have a background common to natural Ab activity, nor NK activity were abrogated by this treatment. These results suggested that DFR mediating cells directly mediated skin xenograft rejection in the recipient mice treated with anti-CD4 mAb, F344 cells, and CY. Such cells may interfere with establishment of mixed chimerism and long-lasting skin xenograft tolerance, presumably in cooperation with CY-resistant Ab activity and NK cells.

Animals↗
PubMed1995

Primary leiomyosarcoma of the maxilla with regional lymph node metastasis. Report of a case and review of the literature.

A rare case of oral leiomyosarcoma diagnosed with the aid of immunohistochemical and electron microscopic examinations together with a review of the literature are reported. The patient was a 70-year-old Japanese man. The primary tumor involved the maxillary gingiva and bone and metastasized to the cervical lymph nodes. On histologic examination the tumor showed invasive growth into the maxillary bone. It was composed of interlacing fascicles of spindle-shaped cells with eosinophilic cytoplasm and elongated, blunt-ended nuclei. The tumor formed extensive metastatic foci in the cervical lymph nodes. On immunohistochemical examination most of the tumor cells were positive for desmin, smooth muscle-specific actin, and myosin. The ultrastructural characteristics of the tumor cells were abundant microfilaments, pinocytotic vesicles, and basement membrane formation. The findings were indicative of a tumor demonstrating myogenic differentiation. A review of the literature during the past 50 years disclosed a total of 60 oral leiomyosarcomas, including our case.

Actin Cytoskeleton↗
PubMed1995

Evidence for a calcium regulated, bidirectional intronic promoter in the murine TCR V alpha 1 gene.

Previous studies of the TCR alpha chain gene have located promoter elements 5' to the start of the various V alpha genes. The only fully characterized enhancer for the entire alpha chain gene (V, J and C genes) has been located approximately 3 kb from the 3' end of C alpha. We now report the existence of additional regulatory elements located in the introns of several murine V alpha genes (V alpha 1, V alpha 3 and V alpha B6.2.16). In the case of V alpha 1, this element appears to be a promoter with bidirectional activity that is not T cell specific. Interestingly, upstream of the promoter in the antisense strand, an open reading frame has been found that codes for a small molecular weight protein (approximately 60 amino acids) that contains a proline-rich region and a tyrosine-isoleucine motif that has homology to Ig beta (the B29 gene product). A rabbit antiserum made against this sequence has confirmed its existence by Western blot and immunoprecipitation. Thus this V alpha 1 intronic promoter has the potential not only to induce the formation of a truncated V alpha 1 gene product, but also regulates the expression of a small molecular weight protein that may be involved in lymphocyte antigen receptor signaling. The activity of this promoter is regulated by changes in intracellular calcium. In the presence of ionomycin the promoter is down-regulated in the sense direction and its activity is enhanced in the antisense direction. This result suggests that this promoter can act differentially to produce two very different gene products. The bidirectional V alpha 1 promoter appears to be the first in the Ig superfamily to induce potentially functional proteins in both directions.

Amino Acid Sequence↗
PubMed1995

Effect of alpha-tocopherol on in vitro and in vivo metabolism of low-density lipoproteins in haemodialysis patients.

It has been reported that some modified low-density lipoproteins (LDLs) such as glycated LDL and malondialdehyde-rich LDL (MDA-LDL) probably exist in the circulation. The present study was undertaken to investigate the in vitro and in vivo metabolism of MDA-LDL occurring in chronic haemodialysis patients and the effects of alpha-tocopherol on these abnormalities. MDA-LDL from haemodialysis patients was degraded more rapidly by human monocyte-derived macrophages and disappeared more slowly from the circulation when compared with LDL from healthy controls. Treatment with alpha-tocopherol at doses of 600 mg/day for 2 weeks resulted in improvement of these metabolic abnormalities depending upon the degree of return to normal MDA concentrations in LDL.

Humans↗
PubMed1995

Correlation among secondary structure, amyloid precursor protein accumulation, and neurotoxicity of amyloid beta(25-35) peptide as analyzed by single alanine substitution.

Structure-neurotoxicity relationships of amyloid beta (25-35) peptide were studied by replacing each amino acid with Ala. In contrast to the general tendency in hydrophobicity-toxicity relationships, replacement of Asn27 yielded a more hydrophobic but less toxic analog and that of Met35 gave a less hydrophobic but more toxic one. Sedimentation profiles and CD spectra indicated that peptide aggregation via intermolecular beta-sheet formation is essential for the neurotoxicity of amyloid beta (25-35) peptide. The correlation between neurotoxicity and amyloid precursor protein accumulation suggested that the latter is one of the pathways of the neuronal death caused by amyloid beta protein.

Alanine↗