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Biomedical subjects

T Maeda

Publications and source records attributed to T Maeda.

At least 289 records · Page 16Linked to original sources
PubMed1999

A possible function of DNA curvature in a vector system that allows efficient expression of heterologous proteins in CHO cells.

A cis-acting element derived from the nontranscribed spacer region of murine rDNA allows efficient expression of heterologous proteins in transformed Chinese hamster ovary (CHO) cells. Analysis of the structural conformation of this cis-acting element revealed that it has a DNA curvature. Whether the DNA curvature plays any roles in regulating expression of heterologous proteins or not has been studied.

Animals↗
PubMed1999

The significance of stromal desmoplasia in intrahepatic cholangiocarcinoma: a special reference of 'scirrhous-type' and 'nonscirrhous-type' growth.

Fifty-eight surgically resected cases of intrahepatic cholangiocarcinoma (ICC) were examined grossly and microscopically. We microscopically categorized the ICC into two groups, "scirrhous-type" ICC (SICC) and "nonscirrhous-type" ICC (NSICC), according to the degree of the stromal desmoplasia in the tumor. We next assessed the histologic characteristics including proliferative activities and prognoses. Additionally, the prognostic factors of ICC were examined by univariate and multivariate analyses. Histologically, the incidences of lymphatic permeation and perineural invasion in SICC (85.7% and 100.0%, respectively) were significantly higher than those in NSICC (47.7% and 45.6%, respectively). The mean MIB-1 labeling index of SICC (mean+/-standard deviation, 29.9%+/-14.3%) was significantly higher than that of NSICC (mean+/-standard deviation, 19.1%+/-14.3%). Additionally, the 1- and 3-year survival rates of the SICC were 64.3% and 22.0%, respectively, and those of NSICC were 72.8% and 55.8%, respectively. The survival rate of SICC was significantly lower than that of NSICC. Overall, lymphatic permeation, intrahepatic metastasis, and lymph node metastasis were all considered to be independent prognostic factors for a worse prognosis based on the multivariate analyses, whereas our new category based on stromal desmoplasia or other variables were not. Our study thus indicates that lymphatic permeation, perineural invasion, and a higher proliferative activity of tumor cells carry a poorer prognosis in SICCs than in NSICCs. Although the overall independent prognostic factors were lymphatic permeation, intrahepatic permeation, and lymph node metastasis based on a multivariate analysis, a detailed histologic examination related to the stromal desmoplasia in the tumor is also considered to be useful for evaluating the biologic behavior of the ICC.

Adult↗
PubMed1999

Low prevalence of Helicobacter pylori in individuals with HTLV-I infection.

BACKGROUND: The prevalence of Helicobacter pylori in HIV-positive individuals is significantly lower than in HIV-negative controls. However, its prevalence in individuals infected with human T-cell leukaemia virus type I (HTLV-I), another important member of the human retrovirus family, has not been previously investigated. OBJECTIVE: To establish the prevalence of H. pylori in HTLV-I-positive individuals in the Nagasaki Prefecture, which is an area endemic for HTLV-I. METHODS: We examined sera from 146 HTLV-I-positive individuals with a mean age of 56.7 years, consisting of 45 adult T-cell leukaemia (ATL) patients, 13 HTLV-I-associated myelopathy (HAM) patients and 88 healthy carriers. Serum samples of 292 age- and sex-matched HTLV-I-negative controls were also examined. Serum anti-H. pylori immunoglobulin (Ig) G antibody was examined using an enzyme-linked immunosorbent assay kit. Twenty-eight HTLV-I-positive patients were examined endoscopically, assessed for H. pylori by culture, histology and CLO test using gastric biopsy specimens, and gastritis in these patients was also graded histologically. RESULTS: The seroprevalence of H. pylori was 48% in HTLV-I-positive individuals versus 64% in HTLV-I-negative controls (P < 0.01). In the three HTLV-I-positive groups, ATL patients and carriers had significantly lower seroprevalence of H. pylori than the HTLV-I-negative controls (P < 0.05). Assessment of H. pylori using gastric biopsy specimens also showed a significantly lower prevalence of H. pylori infection in HTLV-I-positive patients than controls (46% versus 70%, P < 0.05). Histological examination showed a significantly higher degree of activity, inflammation and glandular atrophy in the antrum and corpus in H. pylori-positive patients compared to H. pylori-negative patients. H. pylori-positive patients with HTLV-I infection had a more severe degree of glandular atrophy in the corpus than H. pylori-positive controls without HTLV-I infection. CONCLUSION: We have found a reduced prevalence of H. pylori in HTLV-I-positive individuals. Whatever the explanation, infection with HTLV-I does not predispose to the risk of H. pylori infection.

Adult↗
PubMed1999

Diversity of leukaemic cell morphology in ATL correlates with prognostic factors, aberrant immunophenotype and defective HTLV-1 genotype.

To investigate the diversity of morphology in adult T-cell leukaemia/lymphoma (ATL) and its possible association with the pathophysiology of ATL, we selected 36 acute cases and 14 chronic cases phenotypically confirmed to have >90% ATL cells in peripheral blood mononuclear cells. Prototype ATL cells were observed in all cases, although the percentage of all lymphoid cells varied considerably (48.9 +/- 23.8 in acute type, 29.6 +/- 18.9 in chronic type; P = 0.015). Chronic lymphocytic leukaemia (CLL)-like morphology with round nuclei was more frequent in chronic type than in acute type (52.0 +/- 24.9% v 16.6 +/- 13.1%; P < 0.0001). Unusual morphology (UM; lymphoblastic, vacuolated, granular pleomorphic or large cells) was more frequent in acute type than in chronic type (20.1 +/- 18.7% v 2.7 +/- 3.2%; P < 0.0001). Furthermore, there were significant negative and positive correlations of % CLL-like cells and % UM cells respectively, with serum LDH level, hypercalcaemia, performance status, and total number of involved lesions. Cases with aberrant immunophenotype (n = 6) or defective HTLV-1 integration (n = 22) showed lower % CLL-like cells and higher % UM cells than other cases, respectively. Cases with >50% CLL-like cells (n = 7; all chronic type) were younger (53.1 +/- 12.2 v 66.9 +/- 10.6 years; P = 0.038) and showed longer acute-crisis free survival (mean: 16.7 v 3. 0 years; P = 0.012) than chronic cases with <50% CLL-like cells. These results suggest that diversity in genotype, phenotype, morphology and behaviour of ATL are closely associated, and that CLL-like morphology is a good prognostic factor for chronic type.

Adult↗
PubMed1999

Risk of recurrence of fetal chromosomal aberrations: analysis of trisomy 21, trisomy 18, trisomy 13, and 45,X in 1,076 Japanese mothers.

OBJECTIVE: To evaluate the risk of recurrence of fetal chromosomal aberrations in women who had offspring with numeric chromosomal abnormalities. SUBJECTS AND METHODS: This collaborative study consisted of 1,076 Japanese women with a history of offspring with trisomy-21, -18, -13, or 45,X. Second-trimester amniocenteses were performed, resulting in 1,248 fetal karyotypes that were analyzed with reference to prior offspring karyotypes and maternal age. RESULTS: Of the 842 women with trisomy-21 offspring, 10 conceived another such fetus. In 2 women with 3 or more such offspring, parental mosaicism of trisomy-21 was suspected. The incidence of recurrence of trisomy-21 increased with age, and significantly exceeded the incidence of trisomy-21 fetuses in the general population. None of the 170 women with trisomy-18 offspring, and none of the 46 women with trisomy-13 offspring, had another such fetus. Of the 18 women with 45,X offspring, 1 with mos 45,X/46,XX had another such fetus. CONCLUSIONS: The risk of recurrence of trisomy-21 is affected by maternal age and parental germline mosaicism. The risk of recurrence of trisomy-18 or -13 appears to be much lower than that of trisomy-21. Women who give birth to more than 1 offspring with 45,X should be examined for mos 45,X/46,XX.

Adult↗
PubMed1999

Re-innervation in the canine periodontal ligament of replanted teeth using an antibody to protein gene product 9.5: an immunohistochemical study.

The re-innervation process in the periodontal ligament of replanted canine teeth was examined by immunohistochemistry for protein gene product 9.5 (PGP 9.5), a general marker for neurons, and by electron microscopy. Within 1 week of replantation, the periodontal fibers had regenerated, filling the narrow spaces between the alveolar bone and the root surface around the cervical and apical regions. Near the root apex, however, no PGP 9.5-immunopositive nerve fibers were found in the regenerated periodontal ligament except for those in the alveolar half of the ligament. At 2 weeks after replantation, many nerve fibers positive for PGP 9.5 had ascended the periodontal ligament from the thick nerve bundles located near the root apex. Fine nerve endings showing complicated ramification were also present in the apical region. By 3 or 4 weeks after replantation, the vascular network was regenerated and principal periodontal fibers were re-established throughout the entire length of the periodontal ligament. The extensively ramified PGP 9.5-immunopositive structures had increased in thickness and density and showed characteristic tree-like profiles by 3 weeks. Electron microscopy confirmed that most of these structures were Ruffini-like endings, and demonstrated that such nerve terminals were almost regenerated by 4 weeks post-replantation. These results indicated that, in the periodontal ligament of replanted canine teeth, the regeneration of the nerve fibers including mechanosensory receptors first showed signs of regeneration by 2 weeks following tooth replantation and proceeded rapidly thereafter. Regeneration of the periodontal ligament including fiber architecture as well as vascular and neural elements was almost complete by 4 weeks after replantation.

Animals↗
PubMed1999

Ion distribution in matrix parts of glass-polyalkenoate cement by SIMS.

The microstructure of the set glass-polyalkenoate cement has not been undertaken beyond a study where an Electron Probe Micro Analyser was used. The purpose of this investigation was to determine the ion distribution in matrix parts of the set cement by means of Secondary Ion Mass Spectrometry (SIMS). Among the techniques for surface and microscopic analysis, SIMS is said to be the one with the highest sensitivity. O2+ ions were used as the beam probe to detect silicon, aluminum, calcium, sodium, and carbon. The scanning images showed a clear difference among these elements in their distribution. A large amount of aluminum was found throughout the matrix area, with only a slight concentration gradient, while silicon appeared to be concentrated on the surface of the undissolved glass core. The distribution pattern of calcium was not as clear as that shown by aluminum and silicon. A comparatively higher content of carbon was found closer to the glass surface. These results indicate that aluminum plays an essential role in the setting of the matrix and the surface of the glass dissolved by acrylic acid and changed into the siliceous gel.

Aluminum↗
PubMed1999

The Ruffini ending as the primary mechanoreceptor in the periodontal ligament: its morphology, cytochemical features, regeneration, and development.

The periodontal ligament receives a rich sensory nerve supply and contains many nociceptors and mechanoreceptors. Although its various kinds of mechanoreceptors have been reported in the past, only recently have studies revealed that the Ruffini endings--categorized as low-threshold, slowly adapting, type II mechanoreceptors--are the primary mechanoreceptors in the periodontal ligament. The periodontal Ruffini endings display dendritic ramifications with expanded terminal buttons and, furthermore, are ultrastructurally characterized by expanded axon terminals filled with many mitochondria and by an association with terminal or lamellar Schwann cells. The axon terminals of the periodontal Ruffini endings have finger-like projections called axonal spines or microspikes, which extend into the surrounding tissue to detect the deformation of collagen fibers. The functional basis of the periodontal Ruffini endings has been analyzed by histochemical techniques. Histochemically, the axon terminals are reactive for cytochrome oxidase activity, and the terminal Schwann cells have both non-specific cholinesterase and acid phosphatase activity. On the other hand, many investigations have suggested that the Ruffini endings have a high potential for neuroplasticity. For example, immunoreactivity for p75-NGFR (low-affinity nerve growth factor receptor) and GAP-43 (growth-associated protein-43), both of which play important roles in nerve regeneration/development processes, have been reported in the periodontal Ruffini endings, even in adult animals (though these proteins are usually repressed or down-regulated in mature neurons). Furthermore, in experimental studies on nerve injury to the inferior alveolar nerve, the degeneration of Ruffini endings takes place immediately after nerve injury, with regeneration beginning from 3 to 5 days later, and the distribution and terminal morphology returning to almost normal at around 14 days. During regeneration, some regenerating Ruffini endings expressed neuropeptide Y, which is rarely observed in normal animals. On the other hand, the periodontal Ruffini endings show stage-specific configurations which are closely related to tooth eruption and the addition of occlusal forces to the tooth during postnatal development, suggesting that mechanical stimuli due to tooth eruption and occlusion are a prerequisite for the differentiation and maturation of the periodontal Ruffini endings. Further investigations are needed to clarify the involvement of growth factors in the molecular mechanisms of the development and regeneration processes of the Ruffini endings.

Acid Phosphatase↗
PubMed1999

Cytoplasmic liberation of protein gene product 9.5 during the seasonal regulation of spermatogenesis in the monkey (Macaca fuscata).

Primate spermatogenesis is distinguished by yet unidentified mechanisms to regulate its spermatogenetic activity. In contrast to the well documented hormonal regulators, the cellular events responsible for the regulation of the spermatogenesis has not been addressed. By using PGP 9.5-immunohistochemistry, our previous study demonstrated that the monkey spermatogonia are divided into two distinct sub-populations, i.e. cytoplasmic PGP 9.5-positive and cytoplasmic PGP 9.5-negative spermatogonia. By comparing the cytoplasmic expression of PGP 9.5 between the breeding and nonbreeding seasons of the Japanese monkey (Macaca fuscata) in association with PCNA labeling, the present study demonstrates that the cytoplasmic PGP 9.5-positive Ap spermatogonia significantly increases when the spermatogenetic activity declines in the nonbreeding season. An ultrastructural subcellular localization of PGP 9.5 suggests that the increase of the cytoplasmic PGP 9.5 expression is due to a liberation of PGP 9.5 molecule from the nucleus into the cytoplasm. The results provide a theoretical basis by which PGP 9.5 serves as a novel marker for spermatogonial subtypes, which will have further implications for future studies on spermatogenesis. The analysis using this novel marker suggests that the Ap spermatogonia is a key stage to regulate the amount of the sperm produced in response to the hormonal regulators, and the cytoplasmic liberation of PGP 9.5 may serve as a pivotal phenomenon that enables the fully restorable, transient suppression of spermatogenesis in primate.

Animals↗
PubMed1999

Ca2+/calmodulin-dependent protein kinase II inhibitors potentiate superoxide production in polymorphonuclear leukocytes.

The possible role of Ca2+/calmodulin-dependent protein kinase II (CaMK II) in superoxide anion (O2-) production induced by formyl-methionyl-leucyl-phenylalanine (FMLP) was investigated in mouse polymorphonuclear leukocytes (PMNs). KN-93 and KN-62, specific CaMK II inhibitors, augmented FMLP-induced O2- production. KN-92, an analogue which did not inhibit CaMK II, did not affect O2- production. W-7, a calmodulin inhibitor, augmented O2- production when administered at 30 mM for 5 min. KN-93 and recombinant mouse tumour necrosis factor-alpha (rmTNF-alpha) each augmented the maximal production of O2- induced by FMLP, and an additive effect of a combination of KN-93 and rmTNF-alpha was observed. CaMK II activity in the PMNs was increased by FMLP, and the increase was inhibited by KN-93 but not by rmTNF-alpha. These results suggest that the inhibition of CaMK II resulted in the augmentation of FMLP-induced O2- production in PMNs by a mechanism different from that of the augmentation shown by TNF-alpha.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1999

Synthesis and antimicrobial characteristics of novel biocides, 4,4'-(1,6-hexamethylenedioxydicarbonyl)bis(1-alkylpyridinium++ + iodide)s.

Potent new biocides against both bacteria and fungi, 4,4'-(1,6-hexamethylenedioxydicarbonyl)bis(1-alkylpyridinium iodide)s (4DOCBP-6,n) (alkyl chain length, n = 8, 10, 12, 14, 16 and 18) were synthesized, 4DOCBP-6,n is a bis-quaternary ammonium compound (bis-QAC) and has a symmetrical dimeric structure which is composed of two alkylpyridinium iodides connected with a hexamethylenedioxydicarbonyl chain. 4DOCBP-6,10 and 4DOCBP-6,12 exhibited wide and effective antimicrobial spectra, compared with those of typical bactericides, N-dodecylpyridinium iodides (P-12) and benzyldimethyldodecylammonium chloride (BAC), or a popularly-used fungicide, 2-(4-thiazolyl)benzimidazole (TBZ). Their superior properties would be due to the unique dimeric structure which contains two active moieties in a molecule.

Anti-Bacterial Agents↗
PubMed1999

Correlation of a defect of portal perfusion in the dorsal part of segment IV of the liver on CT arterial portography with inflow of the aberrant pancreaticoduodenal vein.

The correlation between an aberrant pancreaticoduodenal vein and a portal perfusion defect in the dorsal part of segment IV as demonstrated on CT arterial portography (CTAP) was investigated. 14 patients with non-tumorous defects of portal perfusion in the dorsal part of segment IV of the liver parenchyma, shown on CTAP underwent CT during pancreaticoduodenal arteriography. The defect on CTAP was shown as an enhanced area resulting from non-portal venous inflow in eight (57%) of 14 patients on CT during pancreaticoduodenal arteriography. In conclusion, the non-portal venous supply via an aberrant pancreaticoduodenal vein occasionally causes a defect of portal perfusion in the dorsal part of segment IV on CT arterial portography.

Aged↗
PubMed1999

Intrahepatic portosystemic venous shunt associated with a large abdominal tumour.

Intrahepatic portosystemic venous shunt (IPSVS) is relatively uncommon, and is usually associated with chronic hepatitis or cirrhosis. We present a case of IPSVS that was considered to be caused by increased blood flow from a large abdominal tumour. The characteristic intrahepatic haemodynamics were demonstrated by CT angiography.

Hepatic Veins↗
PubMed1999

Aberrant gastric venous inflow to the left lobe of the liver parenchyma adjacent to the falciform ligament.

Direct inflow of the aberrant right gastric vein independent of the portal venous system to the liver parenchyma is a well known cause of non-tumorous abnormalities on CT angiography. However, there have been no previous reports of aberrant gastric venous drainage as the cause of non-tumorous abnormalities in the left lobe of the liver parenchyma adjacent to the falciform ligament on CT angiography. We present a case of direct inflow of an aberrant gastric vein to this region of the liver, which influenced the non-tumorous enhancement shown by CT hepatic arteriography.

Angiography↗
PubMed1999

Dipeptidyl peptidase III from rat liver cytosol: purification, molecular cloning and immunohistochemical localization.

Dipeptidyl peptidase III (DPP III) was purified to homogeneity from rat liver cytosol. The calculated molecular weight of the purified enzyme was 82845.6 according to TOF-MS and 82000 on non-denaturing PAGE, and 82000 on SDS-PAGE in the absence or presence of beta-mercaptoethanol. These findings suggest that the enzyme exists in a monomeric form in rat liver cytosol. The enzyme rapidly hydrolyzed the substrate Arg-Arg-MCA and moderately hydrolyzed Gly-Arg-MCA in the pH range of 7.5 to 9.5. The Km, k(cat) and k(cat)/Km values of DPP III at optimal pH (pH 8.5) were 290 microM, 18.0 s(-1) and 62.1 s(-1) x nM(-1) for Arg-Arg-MCA and 125 microM, 4.53 s(-1) and 36.2 s(-1) x nM(-1) for Ala-Arg-MCA, respectively. DPP III was potently inhibited by EDTA, 1,10-phenanthroline, DFP, PCMBS and NEM. These findings suggest that DPP III is an exo-type peptidase with characteristics of a metallo- and serine peptidase. For further information on the molecular structure, we screened a rat liver cDNA library using affinity-purified anti-rat DPP III rabbit IgG antibodies, determined the cDNA structure and deduced the amino acid sequence. The cDNA, designated as lambdaRDIII-11, is composed of 2640 bp and encodes 738 amino acids in the coding region. Although the enzyme has a novel zinc-binding motif, HEXXXH, DPP III is thought to belong to family 1 in clan MA in the metalloprotease kingdom. The DPP III antigen was detected in significant amounts in the cytosol of various rat tissues by immunohistochemical examination.

Amino Acid Sequence↗
PubMed1999

Involvement of gonadal steroid hormone disturbance in altered prolactin receptor gene expression in the liver of diabetic mice.

The levels of mRNA for long and three short forms of prolactin receptor (PRLR) were examined in the livers of normal (db+/db-) and insulin-resistant diabetic (db+/db+) mice to assess the role of gonadal steroid hormones in the regulation of PRLR gene expression in diabetes mellitus. In females, plasma levels of testosterone in diabetic mice were higher, and those of 17beta-estradiol were lower when compared with levels in normal mice. By contrast, diabetic male mice had lower plasma levels of testosterone than normal males and showed no significant difference in the low circulating level of 17beta-estradiol compared with normal males. The short 3 form of PRLR (PRLR3) mRNA was the most abundant in the liver of both normal and diabetic mice. In addition, the level of PRLR3 mRNA in normal females was 8-fold higher than in normal males. The level of PRLR3 mRNA in diabetic females was approximately a quarter lower than in normal females, whereas the level of PRLR3 mRNA in diabetic males was approximately 2-fold higher than in normal males. During postnatal development, the level of PRLR3 mRNA increased during puberty in normal females, while the level in diabetic females decreased to a nadir at 7 weeks of age followed by a progressive rise. On the other hand, the levels of PRLR3 mRNA in both normal and diabetic males decreased gradually during 5 to 14 weeks of age. Testosterone treatment of diabetic males and females resulted in a 49.1 and 49.8% decrease of PRLR3 mRNA respectively. 17beta-Estradiol treatment slightly (18%) increased levels of PRLR3 mRNA in diabetic males. These results suggest that the hepatic level of PRLR mRNA is regulated by the inhibitory effect of testosterone and the stimulatory effect of estrogen in both normal and diabetic mice.

Animals↗
PubMed1999

Alteration in the expression level of calbindin D28k in the periodontal ligament of the rat molar during experimental tooth movement.

The present immunohistochemical study was designed to investigate changes in the distribution and expression level of calbindin D28k in the periodontal ligament during experimental tooth movement in the rat molar to clarify the physiological role of this protein in the ligament. In normal animals, calbindin D28k-like immunoreactivity appeared sparsely in spindle-shaped cells in the alveolar half of the periodontal ligament. Electron microscopic observations showed that these immunoreactive cells were characterized by well-developed rough-surfaced endoplasmic reticulum and phagosomes--which often contained collagen fibers--suggesting that these cells could be categorized as periodontal fibroblasts. Twelve hours following the onset of the experimental tooth movement, cells positive for calbindin D28k increased in number in the periodontal ligament, especially in the alveolar half of the pressured side. Immunoelectron microscopy showed that the calbindin D28k-immunopositive cells had morphological features similar to those of fibroblasts in the normal ligament, and that these cells occasionally made contact with immunonegative macrophage-like cells. Immunopositive cells gradually decreased in number, and the distribution of the cells and intensity of the immunoreactivity returned to normal levels by 14 days following the induction of the experimental tooth movement. The present results suggest that calbindin D28k plays an important role in the homeostasis and cyto-protection of fibroblasts in the periodontal ligament at the initial phase of experimental tooth movement.

Animals↗