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T Imagawa

Publications and source records attributed to T Imagawa.

At least 55 records · Page 3Linked to original sources
PubMed1999

Molecular epidemiological study of Haemophilus influenzae serotype b strains obtained from children with meningitis in Japan.

We report an epidemiological study of 30 Haemophilus influenzae serotype b (Hib) strains derived from the cerebrospinal fluid of children with meningitis. The Hib strains were biotyped, tested for beta-lactamase production, and genotyped by long PCR-ribotyping, random amplified polymorphic DNA (RAPD) analysis, and genomic DNA restriction fragment length polymorphism (RFLP) analysis by pulsed-field gel electrophoresis (PFGE). The phenotypic study characterized 22 of the strains (73%) as biotype I. A genotypic study using long PCR-ribotyping with HaeIII restriction digestion showed no polymorphisms among these 30 Hib strains, but RAPD analysis with two sets of primers demonstrated two distinctive subtypes: one typical of the strains of biotype group II and the second characteristic of the strains of biotype groups I and IV. Each RAPD group was subtyped into several genotypic groups by PFGE-RFLP with SmaI digestion. The genotyping of clinically isolated Hib strains may help to elucidate transmission routes in community infections, endemicity, and the reasons for vaccine failure.

Child, Preschool↗
PubMed1999

Apoptosis of villous epithelial cells and follicle-associated epithelial cells in chicken cecum.

The process of the disappearance of epithelial cells was examined in chicken cecal villi and follicle-associated epithelium (FAE). The apoptotic epithelial cells with intense DNA-fragmentation and their exfoliation were found in the villous tips. The epithelial cells with weak DNA-fragmentation were seen in the upper portion of the villi and their sparse exfoliations were also found there. Numerous epithelial cells in the intestinal lumen expressed the apoptotic features. A row of apoptotic epithelial cells with DNA-fragmentation was also found in the apical FAE, whereas no M cells exhibited any apoptotic signs. In all cecal regions, CD3+, CD8+, and TCR2+ lymphocytes were predominant in the epithelium at the upper portion of the villi and the FAE. CD4+ lymphocytes were mainly seen in the lamina propria. TCR1+ lymphocytes were not abundant in comparison with TCR2+ lymphocytes in the epithelium. TCR3+ T lymphocytes were rarely detected. These results suggest that the chicken cecal epithelial cells exfoliated into the lumen after the induction of the apoptosis, and that the induction may be involved with CD3+, CD8+, and TCR2+ lymphocytes. No death in M cells suggests that M cells may transform into microvillous epithelial cells.

Animals↗
PubMed1999

Quantitative studies of the optic nerve fiber layer in the chicken retina.

The optic nerve fiber layer (NFL) of the chicken retina was studied quantitatively and morphologically at 17 positions along seven radially arranged bands from the dorsal tip of the pecten oculi using electron microscopy. The number of nerve fibers was counted in areas 6 microm in width x the full thickness of the NFL. Myelinated nerve fibers in the NFL were also identified immunohistochemically using anti-myelin basic protein serum. The dorsal area (dorsal, dorso-temporal and dorso-nasal bands) in the retina had thin NFL and contained the largest number of nerve fibers, which were mainly thin and unmyelinated. The ventral area (ventral and ventro-temporal bands) had a thick NFL and contained a relatively small number of nerve fibers, many of which were myelinated. The nasal band had the thickest NFL and contained as many nerve fibers as the dorsal area, with the temporal band showing a high ratio of myelinated fibers. The band had a thick NFL and contained many nerve fibers with a relatively low ratio of myelinated fibers. The relationship between the number and composition of nerve fibers in the NFL to the chicken visual characteristics was discussed. Although the myelin in the chicken retina was loose type, the myelin-forming cells were similar in appearance to dense oligodendrocytes. retina, morphometry, myelinated fiber, nerve fiber layer.

Animals↗
PubMed1999

[Effective combination therapy of plasma exchange and subsequent cyclophosphamide pulses for catastrophic antiphospholipid antibody syndrome: a case report].

A 7-year-old girl with catastrophic antiphospholipid antibody syndrome was described. She firstly admitted to the local hospital with the complaints of persistent fever and abdominal pain, and was diagnosed as systemic lupus erythematosus with the laboratory findings as follows; positive for antinuclear antibody, anti-DNA antibody, and platelet-associated IgG, thrombocytopenia, and hypocomplementemia. 10 days after the initiation of oral prednisolone, she suddenly manifested tonic convulsion and unconsciousness accompanied by high fever. Because of the unresponsiveness to the methylprednisolone pulse therapy for supposed CNS lupus, she was transferred to our hospital. Her unconsciousness persisted, and pulsation on dorsalis pedis was not palpable on admission. Laboratory investigation revealed the falsely positive VDRL, a prolonged aPTT, positive for lupus-anticoagulant and antiphospholipid antibody. The magnetic resonance image demonstrated multiple spotty hyperintensity (T2) in the brain consistent with multiple hemorrhagic infarcts. Arteriogram demonstrated the infarct of dorsalis pedis, and coronary aneurysms. These findings were compatible with the criteria of catastrophic antiphospholipid antibody syndrome, she was diagnosed as catastrophic antiphospholipid antibody syndrome. The plasma exchange and subsequent cyclophosphamide-pulse therapy, which was given once a month for first 6 months, and later, at 3 months intervals, was effectively administered. This combination and oral anti-thrombotic therapy revealed effective for this kind of fatal disorder.

Anticoagulants↗
PubMed1999

[An infant of autoimmune hepatitis (type I) with cirrhosis].

A 6 year-old boy with autoimmune hepatitis accompanied with cirrhosis was reported. He was admitted to our hospital because of abdominal distention, high fever, and diarrhea. Laboratory examination revealed abnormalities in hepatic function, cholestasis, anemia, thrombocytopenia, hypoalbuminemia, hypocomplementemia, and low concentration of coagulation factors. Abdominal MRI, and asialoglycoprotein receptor-mediated liver scintigraphy strongly indicated liver cirrhosis. Viral hepatitis, Wilson's disease, and antitrypsin deficiency were excluded serologically. Instead, hypergammaglobulinemia, and positive antinuclear antibody suggested autoimmune hepatitis, and the survey of anti-mitochondrial antibody, anti-smooth muscle antibody, and anti-LKM-1 antibody was negative, indicating type I autoimmune hepatitis. Finally, the histology of liver biopsy specimen indicating the destruction of hepatic lobular architecture, dense mononuclear cell infiltrates, and severe fibrosis confirmed the diagnosis. He was treated firstly with methylprednisolone pulses, and then prednisolone p.o. + azathioprine p.o. All of the abnormal laboratory parameters improved to normal levels, indicating that the immunosuppressive therapy will be effective for the severe AIH with cirrhosis.

Child↗
PubMed1999

[A child of microscopic polyarteritis nodosa effectively treated with intravenous methylprednisolone pulses and serial cyclophosphamide pulse therapy].

Microscopic polyarteritis nodosa (mPAN) is a rare disorder in pediatric field of systemic small vessel vasculitis, and affects skin and musculoskeletal system accompanied by progressive necrotizing glomerulonephritis. We described here a 15-year-old boy with positive anti-neutrophil cytoplasmic antibody (MPO-ANCA) and severe mPAN, who was effectively treated with intravenous methylprednisolone pulse therapy followed by monthly cyclophosphamide pulses for 1 year. The histologic examination of renal biopsy specimen showed a severely desolated disease characterized by fibrinoid necrosis, crescent formation of most glomeruli and interstitial infiltration of inflammatory cells. The elevated titers of MPO-ANCA were useful markers for diagnosis, and the serial determinations of the antibody titers were indicative of disease activity. Moreover, dramatic clinical improvement after the induction of the combinatorial therapy and the disappearance of MPO-ANCA was correlated in the disease course. In this report, the serial determination of MPO-ANCA constituted a useful diagnostic tool and a sensitive marker of disease activity.

Adolescent↗
PubMed1999

[Improvement of the maintenance therapy after methylprednisolone pulse therapy--effect of prednisolone combined with immunosuppressants].

OBJECTIVES: We investigated the effect of the combination therapy of prednisolone (PSL) and immunosuppressants after methylprednisolone pulse therapy. METHODS: A protocol of PSL (15-20 mg/day) and mizoribine (150-200 mg/day) after methylprednisolone (mPSL) pulses was used for 2 years to treat 7 patients (PSL + MZB group). Cyclophosphamide (CYC) pulse therapy was added to the combined therapy in 4 patients with severe lupus nephritis. The total dose of predinisolone, and side effects were compared with those in 6 patients who were treated with PSL (30 mg/kg) alone after mPSL pulse therapy (PSL group). RESULTS: No relapses occurred in the PSL + MZB group, although all of 6 patients relapsed in the PSL Group. The total doses of PSL in the PSL + MZB group was about 70% of the PSL Group. There were two patients with Herpes-Zoster infection and one patient with liver dysfunction as side effects, with no differences in the frequency of side effects between the was groups. CONCLUSIONS: Combination maintenance therapy with prednisolone and immunosuppressants after methylprednisolone pulse therapy was effective in preventing relapse.

Adolescent↗
PubMed1998

Synthesis and pharmacological activity of triazolo[1,5-a]triazine derivatives inhibiting eosinophilia.

In continuation of our previous work on eosinophilia inhibitors, we synthesized an additional series of inhibitors, which consisted of 5-amino-1-[(methylamino)thiocarbonyl]-1H-1,2,4-triazole derivatives and a newly developed series of 1,2,4-triazolo[1,5-a]-1,3,5-triazine derivatives. We evaluated their inhibitory activity on the airway eosinophilia model, which was induced by the intravenous (iv) injection of Sephadex particles. In the 1,2,4-triazole series with various substituents at the 3 position of the triazole ring such as 2-furyl, pyridyl, and phenoxy, none of derivatives had comparable activity to the previously reported compound GCC-AP0341, 5-amino-3-(4-chlorophenyl)-1-[(methylamino)thiocarbonyl]-1H-1,2, 4-triazole. In the triazolo[1,5-a]triazine series, 2-(4-chlorophenyl)-6-methyl-1,2,4-triazolo[1,5-a]-1,3, 5-triazine-7(6H)-thione (3h) was highly potent, and when given orally it had an ID50 value of 0.3 mg/kg, which is comparable to that of GCC-AP0341. The fact that the structure-activity relationship of these two series was quite similar suggests that a common substructure, such as the 1,2,4-triazole ring with a substituted phenyl ring at the 3 position and a thiocarbonyl moiety at the 1 position, could contribute to the activity. Our selected compound 3h was less active than GCC-AP0341 in the antigen-induced hyper-responsiveness model in guinea pigs; however, we plan to carry out further studies on eosinophil functions, especially on their activation, using our two compounds, 3h and GCC-AP0341.

Animals↗
PubMed1998

Developmental study on reduction and kinks of the tail in a new mutant knotty-tail mouse.

The knotty-tail (knt/knt) mouse has a short and knotty tail. The tail deformity is caused by a decrease in the number of caudal vertebrae and a deformity of them in the distal part of the tail. The objective of the study was to determine how reduction and kinks of the tail region were formed during secondary body formation. By day 12.0 pc, the somitogenesis of knt/knt embryos was completed; the number of caudal somites more or less agreed with those of the caudal vertebrae in knt/knt mice and were similar to those of knt/+ embryos. On the other hand, the somitogenesis of knt/+ embryos continued up to day 12.5 pc. The somites below about the sixth caudal somite were wedge-shaped with a dorsal apex in knt/knt embryos. The location of abnormal somites also corresponded well to that of deformed caudal vertebrae. Abnormal somitogenesis was always preceded by abnormalities in the presomitic region. Under gross observation, this could be seen to become markedly thickened, and histologically its dorsoventral diameter increased in the transverse plane on days 10.5-12.0 pc. In the mesenchyme there was often obvious cell death at the boundary of the unsegmented area and the tail bud after day 10.5 pc. These results suggested that the shortness of tail was primarily caused by the agenesis of distal caudal vertebrae following the agenesis of distal caudal somites, and partly by the disappearance of the presomitic part due to cell death, while the tail kinks were caused by the deformation of each caudal vertebra following disturbances of the caudal somites. Also, it is highly probable that the prominent cell death at the boundary of the unsegmented area and the tail bud may involve a defect or deformity of somites in this mutant.

Animals↗
PubMed1998

Na+/Ca2+ exchanger overexpression impairs calcium signaling in fibroblasts: inhibition of the [Ca2+] increase at the cell periphery and retardation of cell adhesion.

We examined the Ca2+ handling property and cell function of CCL39 fibroblasts highly overexpressing the cardiac isoform (NCX1) of Na+/ Ca2+ exchanger. In NCX1 transfectants in 146 mM Na+, ionomycin, alpha-thrombin or thapsigargin only produced a small transient increase in [Ca2+]i compared to the large increase seen in control cells, although resting [Ca2+]i was not significantly different between these cells. In Na+-free medium, in contrast, the [Ca2+]i responses in NCX1 transfectants and control cells stimulated with these agents were not different, indicating that the Ca2+ content of the intracellular store(s) does not decrease on NCX1 transfection. The expression levels of the endoplasmic reticulum and plasma membrane Ca2+-ATPases, and thrombin- or serum-stimulated cell growth were not altered in NCX1 transfectants. The latter finding suggests that Ca2+ signaling in the nucleus is not impaired appreciably. On fluorescence imaging and confocal microscopy, we found that [Ca2+] did not increase in the peripheral cytoplasm of these cells treated with alpha-thrombin in Na+-containing medium. In these NCX1 transfectants, activation of the plasma membrane Ca2+-activated K+ channels by thrombin or ionomycin was markedly suppressed, and the integrin-mediated adhesion to substrate was significantly delayed compared with control cells. NCX1-overexpressing CCL39 cells thus seem to be a good model with which we can study the Ca2+-regulated membrane processes under physiologically relevant conditions.

Animals↗
PubMed1998

Distribution of lymphoid tissue in the caecal mucosa of chickens.

In order to clarify the fundamental structure of the host defence mechanism in chicken caeca, a detailed analysis of the distribution of lymphoid nodules (LNs) was carried out on longitudinal sections of both the mesenteric (side of the ileocaecal ligament) and the antimesenteric mucosa. An overwhelming majority of solitary or aggregated LNs were located in the mesenteric mucosa, although a few were also found in the antimesenteric mucosa. Of the total LNs, 45.7% were detected at the proximal 7.8% section in the caecal tonsil. LNs (21.4%) were also concentrated in the distal 22.0% section corresponding to the apex. A moderate concentration of LNs (13.1%) was found at the transitional 20.0% region between the base and body. Approximately 80.2% of total LNs were found at the above 3 regions in the mesenteric mucosa. In many cases, the frequency of LNs in the caecal tonsils was opposite to that at the apices. Aggregated LNs were mainly found in the caecal tonsils, transitional region and apex. Almost all aggregated LNs consisted of fundamental nodular units possessing M cells in their follicle associated epithelia. The aggregated LNs in the above 3 regions therefore could provide immunological surveillance against caecal luminal contents. In particular, the cooperative function between LNs of the caecal tonsil and apex might be highly important in maintaining the caecal microenvironment.

Animals↗
PubMed1998

Proliferation and cellular kinetics of villous epithelial cells and M cells in the chicken caecum.

The proliferation sites and cellular kinetics of villous epithelial cells and M cells in the intestine of the adult chicken have never been clarified. In this study, we determined the proliferation sites in the chicken caecum using colchicine treatment and detection of proliferative cell nuclear antigen (PCNA). The cellular kinetics of these cells were also studied using bromodeoxyuridine (BrdU) as a tracer. Enterocytes in their mitotic period were observed along the entire length of the intestinal crypt of the caecum, with a denser distribution in the middle portion of the crypt, except for the caecal tonsil. The centres of distributions were at 49% of the distance from the bottom of the crypt in the base and 41% in the apex of the caecum. In the caecal tonsil, the centres of distributions were at 64% in the long type of crypt from the bottom of the crypt and at 44% in the short type of crypt. On the other hand, the PCNA-positive enterocytes were distributed more densely at the bottom of the crypt, except for the caecal tonsil. The centres of distributions were at 36% in the base from the bottom of the crypt, 37% in the body, and 34% in the apex. In the caecal tonsil, they were at 54% in the long type of crypt and 44% in the short type. The BrdU-labelled enterocytes reached to the basement of the intestinal villi in all caecal portions at 1 d after the BrdU administration. The leading edge of the labelled enterocytes disappeared from the villous tips at 4 d in the base and the body and 3 d in the apex. In the caecal tonsil, the BrdU-labelled microvillous epithelial cells and the M cells appeared near the orifice of the crypt at 1 d, and BrdU-labelled M cells were not observed in the crypt. Thereafter, almost all of these cells disappeared at 5 d from the follicle associated epithelium (FAE). These results suggest that M cells are transformed from their precursors within 1 d, and the turnover time for M cells occurs within 4 d after the cell division of the precursors.

Animals↗
PubMed1998

Does binding of ouabain to human alpha1-subunit of Na+, K+-ATPase affect the ATPase activity of adjacent rat alpha1-subunit?

To ascertain whether ouabain binding to human alpha1-subunit influences coexpression of rat alpha1-subunit, the ouabain-sensitive profiles of Na+,K+-ATPase activity and 86Rb+ uptake activity and ouabain binding capacity were measured in HeLa cells stably expressing rat alpha1-subunit. The ouabain-sensitive profile of ATPase and 86Rb+ uptake activity seemed to be the sum of two components, one with high and one with low apparent affinity to ouabain, which were similar to that observed in HeLa and NRK-52E cells derived from human and rat, respectively. The ATPase activity with low sensitivity to ouabain increased in simple proportion to the amount of the rat alpha1 mRNA derived from transfected cDNA, which was determined by the reverse transcription-polymerase chain reaction method. The turnover number of the human Na+,K+-ATPase activity obtained from the ratio of the Na+,K+-ATPase activity to the ouabain binding capacity is about 150/sec. The expression of the rat alpha1-subunit had no effect on the turnover numbers of the Na+,K+-ATPase activity with high affinity to ouabain estimated from the ouabain binding capacity as the active site concentration. These results suggested that the ouabain bound to human alpha1-subunit did not inhibit the ATPase activity of the coexpressing rat alpha1 in these cells.

Animals↗
PubMed1998

Quantitative studies of nuclear bodies in astrocytes of chicken spinal cord following axotomy.

The present study was designed to reveal whether astrocytic activation following axotomy causes a numerical increase of nuclear bodies (NBs) in chicken astrocytes. Astrocytes in the spinal cord were activated by a unilateral spinal nerve transection. The frequency of NBs was calculated at the lateral motor columns of the normal group and at the ipsi- and contralateral sides of operated group. In the growing chickens, NBs of each astrocyte were a few and decreased steadily in number with age. In the operated chickens, the frequency of NBs elevated temporarily both in the ipsi- and contralateral sides, and reached its maximum value by 30 post-operative days. The frequency of NBs increased more prominently in the operated side than in the unoperated side. Thus, the present study provides the first evidence for a significant increase in the number of NBs in the hyperactive astrocytes caused by axotomy.

Animals↗
PubMed1998

[Clinical analysis of 11 cases of juvenile dermatomyositis and polymyositis].

Juvenile dermatomyositis (JDM) is characterized by microvasculopathy of the striated muscle, which indicates different etiology, clinical manifestation and prognosis from the adult-onset dermatomyositis. We experienced 10 cases of JDM and 1 case of juvenile polymyositis (JPM) in the recent 14 years, and analyzed clinical manifestation, laboratory findings, treatment anrognosis. The cases were 9 girls and 2 boys. The onset of the disease was 2 years of age in 2 patients, and 9 to 13 years of age in 9 patients. During the follow-up courses, no cases were dead or complicated with neoplasm. Skin rash was the most frequent manifestation at the onset, and facial erythema was common. Muscle weakness was observed only in 4 cases at the onset, and in all cases muscle enzymes including creatine kinase and aldolase were elevated. The clinical course was classified into three groups; monocyclic (5 cases), chronic and recurrent (4 cases), and fulminant (2 cases). Prognosis depended not on the degree of the elevated serum muscle enzymes, but on the initial therapy employed at the onset of the disease. Five cases including 2 cases of fulminant type were initially treated with methylprednisolon pulse therapy, and all of these had no recurrence. On the other hand, 6 cases were started the therapy with p.o. prednisolone. Four of them had frequent recurrences in accordance with tapering of prednisolone. These cases were effectively treated with the combination with immunosuppressants. In previous reports, JDM and JPM were reported to be a disorder which had relatively favorable prognosis. But we found that one third of the cases had chronic and recurrent courses. Methylprednisolone pulses as initial therapy may be effective in preventing the chronicity and recurrence of the disease.

Adolescent↗
PubMed1997

In vivo determination of ultratrace amounts of prostaglandin in plasma by high-performance liquid chromatography/laser-induced fluorometry/ultrasensitive laser spectrometry under severe conditions.

We succeeded in determining ultratrace prostaglandin amounts in plasma, at the femtomolar level, using laser-induced fluorometry through a complete redesign of the analytical procedures. Practical samples, especially plasma, contain large amounts of admixtures, and prostaglandin in plasma (pg/mL) has been considered to be difficult to detect because the samples and reagents supplied by conventional procedures are neither pure nor stable enough to get good results by ultrasensitive laser spectrometry. We completely redesigned the analytical procedures after careful investigations of the reagent purification and the column separation conditions based on a newly found behavior of the reagent and derivatized prostaglandin in a small quantity of ethanol in the mobile phase. A lower determination limit of 23 pg/mL (65 fmol) was achieved, the variance was 12% at 25 pg/mL, and the recovery rate was 88-89%. This method was applied to in vivo analysis of the concentration of prostaglandin E1 administered as a prodrug of prostaglandin E1 (delta(8)-9-O-butyryl prostaglandin F1 butyl ester, AS-013) by intravenous infusion to beagle dogs. A clear correlation between the change of blood pressure and the prostaglandin E1 concentration was confirmed.

Alprostadil↗