Search PubMed⌕ Search

Biomedical subjects

T Maeda

Publications and source records attributed to T Maeda.

At least 487 records · Page 27Linked to original sources
PubMed1997

Mucus escape reaction that involves the mandible: a case report and diagnostic imaging considerations.

We present a case of mucus escape reaction in which we encountered difficulty in interpreting the images acquired by plain radiography, computed tomography, and magnetic resonance imaging. The 48-year-old male Japanese patient was referred for evaluation of a gradual swelling subjacent to the inferior border of the left mandible. At the early imaging examinations, magnetic resonance imaging provided information crucial to resolving the issue of whether the lesion consisted of a central malignant disease process or a malignant disease in the submandibular space or both of these two separate disease entities. Magnetic resonance imaging demonstrated no evidence of tumorous lesion, but rather showed a fluid-containing cavity that was also confirmed by the subsequent intrasurgical inspection. On further consideration of these imaging findings, we concluded that the entity was mucus escape reaction with simultaneous occurrence of an intraconnective tissue hemorrhage adjacent to the left submandibular gland, concomitant extensive bony defect of the left mandible and lingual cortical defect, and chronic sialoadenitis of the left submandibular gland.

Diagnosis, Differential↗
PubMed1997

Vidarabine therapy for virus-associated cystitis after allogeneic bone marrow transplantation.

We describe a method of diagnosing virus-associated cystitis after allogeneic bone marrow transplantation (BMT) and treatment with vidarabine therapy. At 7-10 days post-BMT when cystitis was suspected, we observed urinary sediments by the Papanicolaou stain to detect virus inclusion bodies. When positive, we examined urinary sediments by transmission electron microscope and measured the diameter of viral particles to determine the families. This process needed only 4 days. Among 16 consecutive cases, adenovirus and polyomavirus were each detected in three. Adenovirus caused hemorrhagic cystitis in two cases and cystitis without macroscopic hematuria in one case. Polyomavirus caused cystitis without macroscopic hematuria in one case. Polyomavirus was also detected in two cases without any symptoms. Vidarabine (10 mg/kg/day i.v.) was administered for 5 days as one course. Soon after one course of vidarabine, most symptoms subsided and virus inclusion bodies disappeared in all cases except for one with severe hemorrhagic cystitis. From these experiences, vidarabine reduces excretion of adenovirus and polyomavirus in the urine of BMT recipients and improves clinical symptoms in some cases of cystitis associated with these viruses.

Adenoviridae Infections↗
PubMed1997

Quantitative characterization and potential function of membrane Fas/APO-1 (CD95) receptors on leukaemic cells from chronic B and T lymphoid leukaemias.

The expression and function of the Fas-receptor (Fas-R) were examined in chronic lymphocytic leukaemia (CLL), hairy cell leukaemia-variant (HCL-v) and adult T-cell leukaemia (ATL). The expression of Fas-R in freshly isolated leukaemic cells was qualitatively and quantitatively different between each disease; faint in B-CLL, moderate in HCL-v and strong in ATL. Both full-length and alternatively spliced truncated forms of Fas mRNA were detected even in CLL B cells with faint to negative Fas-R, and Fas mRNA was also shown to be capable of increasing in vitro expression, i.e. the message was functional. In contrast, Fas-R expression on ATL cells was heterogenous and usually intense with a mean density approximately 3-fold higher than that of normal T cells. Fas-R was confirmed to have the potential function for anti-Fas monoclonal antibody-mediated cell death in vitro in Fas-R+ ATL cells. The expression level of Fas-R on the cells was higher in chronic than acute ATL (10,360 v 6260 antibody-binding capacity per cell, mFasABC; P<0.05) and was inversely correlated with serum LDH activity, suggesting that the strong Fas-R accounts for the slow progression of chronic ATL and the negative Fas-R protects from Fas-mediated cell death. These results show that Fas-R expression on leukaemic cells is valuable in their characterization and perhaps their function, and may contribute to the progression and immune evasion of malignant clones.

Apoptosis↗
PubMed1997

Distribution of blastodermal cells transferred to chick embryos for chimera production using windowed eggs.

1. To improve the production of chimeras, the distribution of donor blastodermal cells after transferring into recipient embryos was examined morphologically. 2. Donor blastodermal cells were distributed near the site of injection in the epiblast and in the subgerminal cavity and yolk. Some filled the hole made by the micropipette and were distributed outside the epiblast. Many were buried in yolk. In some cases, more donor blastodermal cells were located in the yolk than in the subgerminal cavity and some were located 800 microm below the under-surface of the epiblast. 3. It is recommended that injection should be as shallow as possible to increase the proportion of chimeras produced, and that some means is needed to prevent blastodermal cells from escaping from the hole produced by injection.

Animals↗
PubMed1997

Dimerization and DNA binding facilitate alpha-helix formation of Max in solution.

Max is a basic region/helix-loop-helix/leucine zipper (b/HLH/Z) protein that forms a hetero-complex with the Myc family proteins Myc, Mad, and Mxi1, and a homo-complex with itself. These complexes specifically bind to double-stranded DNA containing CACGTG sequences. Here, we report on the structural properties in aqueous solution of a 109-amino-acid protein, Max110, corresponding to the N-terminal domain of Max containing the b/HLH/Z motif (residues 2-110), as characterized by combined use of circular dichroism (CD) and sedimentation equilibrium experiments. The results showed that the alpha-helical content of Max110 increases with increasing protein concentration. The sedimentation equilibrium data indicated that Max110 exists as a monomer at low protein concentration, and forms a dimer at high protein concentration. Further increases in the alpha-helical content of Max110 occur upon addition of DNA with the CACGTG recognition sequence. Thus, dimerization and binding to DNA of Max both favor an increase of the alpha-helical content.

Amino Acid Sequence↗
PubMed1997

T-cell receptor in Sjögren's syndrome.

Studies on the TCR repertoire of T cells in several inflamed lesions of SS patients have shown that there exist no unique TCR V family genes, although TCR V gene usage is relatively restricted. Analysis of the clonality of infiltrating T cells shows that some T cells expand clonally in lesions, suggesting that these cells were induced by antigen-driven rather than superantigen-driven stimulation. The restricted usage of the TCRJ beta, V alpha and J alpha genes also supports the notion that all expanded T cells do not accumulate due to superantigen. Junctional sequence analysis has revealed some conserved amino acid sequence motifs in the TCR CDR3 region, which is the antigen-binding site on T cells. These observations strongly suggest that pathogenic T cells in lesions recognize limited epitopes on autoantigens in the context of HLA. These findings are similar to TCR on T cells in rheumatoid synovium, as described elsewhere [51]. Intriguingly, T cells in lacrimal and labial salivary glands recognize common epitopes, but T cells in the kidney react with different autoantigens from those in minor salivary glands. In the future, the peptides recognized by pathogenic autoreactive T cells should be clarified to elucidate the mechanism for the progression of SS. Moreover, we predict that a vaccination with analogue peptides, to induce autoreactive T cells to anergy, might provide a new strategy for the specific treatment of SS.

Humans↗
PubMed1997

Successful treatment with cyclosporine in a case of hemophagocytic syndrome manifesting as severe liver dysfunction.

Forms of hemophagocytic syndrome, which affects mainly children, vary from mild to very severe and often fatal. We describe an adult patient with hemophagocytic syndrome in whom severe liver dysfunction developed. The condition continued to deteriorate despite treatment with plasma exchange, high-dose gamma globulin, and corticosteroid therapy. Treatment with cyclosporine (2.3 mg/kg/day) dramatically improved the condition and normalized liver function. Cyclosporine reduced the serum levels of ferritin, interferon-tau, interleukin-6, and soluble interleukin-2 receptor. These findings suggest that hemophagocytic syndrome accompanied with severe liver dysfunction results from hypercytokinemia, and cyclosporine is useful in preventing a fatal outcome during the acute phase.

Adult↗
PubMed1997

Small hepatocellular carcinoma on magnetic resonance imaging. Relation of signal intensity to angiographic and clinicopathologic findings.

RATIONALE AND OBJECTIVES: The authors discuss the clinicopathologic features and angiographic vascularity of various signal intensity patterns on magnetic resonance (MR) imaging of small hepatocellular carcinomas (HCCs). METHODS: Magnetic resonance images of 88 resected HCCs (< or = 3 cm) were obtained using T1- and T2-weighted spin-echo images and T1-weighted images after gadolinium (Gd)-DTPA administration. Images were compared with angiographic and histopathologic findings. RESULTS: Forty HCCs (45%) were depicted on T1-weighted images, 51 (58%) on T2-weighted images, and 41 (49%) on T1-weighted images after Gd-DTPA administration. Overall, 64 (76%) were found on at least one image. On T1-weighted images, hyperintense HCCs histologically showed fatty metamorphosis and portal tracts within the tumor. On T2-weighted images, HCC hyperintensity correlated with expansive growth, peliotic change, and hypervascularity. By contrast, HCCs that were undetected or hypointense on T2-weighted images were well differentiated with replacing growth and portal tracts. On T1-weighted images after Gd-DTPA, hyperintense HCCs had peliotic change; undetected HCCs were well differentiated and hypovascular. CONCLUSIONS: Histologic grade, vascularity, portal tracts and peliotic change correlate with MR signal intensity. For hyperintense HCCs on T1-weighted images and hypo- or isointense HCCs on T2-weighted images, treatment methods must be assigned with the consideration that HCCs may be receiving transsinusoidal and portal blood supplies.

Adult↗
PubMed1997

PCR-RFLP analysis as an aid to genetic counseling of families of Japanese patients with group A xeroderma pigmentosum.

Because Japanese patients with complementation group A xeroderma pigmentosum (XP-A) show early skin cancer and severe neurologic dysfunction, their family members are greatly concerned about the risk of inherited disease. In contrast to western XP-A patients, almost all Japanese XP-A patients have two of the three mutations (nonsense mutation in exon 3, splicing mutation in intron 3, and non-sense mutation in exon 6), which are easily detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. This work was aimed to see whether PCR-RFLP analysis is useful for genetic counseling of XP patients' siblings who are potential carriers of an XP-A gene mutation. In two of the three case studies presented, the probands were homozygous for the splicing mutation in intron 3 of the gene. In their siblings receiving genetic counseling, no mutation was found in the mutation site in one case, and one splicing mutation was found in the second case. In the third case, the proband was a compound heterozygote for the splicing mutation and for an unidentified mutation; in her sibling, no mutation was found in either of these mutation sites. No mutation was found in the siblings' spouses. On the basis of these findings, we reassured the prospective parents that there was little probability of having XP children, but in the second and third cases, we told them that their apparently unaffected children might be carriers. Each couple subsequently had one unaffected child. Thus, PCR-RFLP analysis is useful for genetic counseling of family members of XP-A patients.

Adult↗
PubMed1997

p21 (WAF1/Cip1/Sdi1/Pic1) mRNA is expressed in neuroblastoma cell lines but not in Ewing's sarcoma and primitive neuroectodermal tumor cell lines.

The p21 protein inhibits the activity of cyclin-Cdk complexes and suppresses cell cycle progression. Wild type p53 can induce p21, but mutated p53 cannot. Previous studies have demonstrated that mutation of p53 is absent in neuroblastoma (NB). These reports prompted us to examine whether p53 induced p21 in NB. We examined the expression of p21 and p53 mRNA in eight NB, two Ewing's sarcoma (ES) and two primitive neuroectodermal tumor (PNET) cell lines by Northern blot analysis, and sequenced p53 cDNA of these cells. Although p53 mRNA was detected in all analyzed cell lines by Northern blot analysis, p21 mRNA was detected in six NB but not in two NB, two ES and two PNET cell lines. We detected the point mutation of p53 at codon 273 (CGT to TGT) in one NB and two ES cell lines. The non-transforming substitution at codon 72 (CCC to CGC) was detected in all analyzed cell lines. One PNET cell line had a large deletion of p53 cDNA. These results showed that p21 mRNA was usually expressed in NB but not in ES and PNET. This may suggest that the down stream of the p53 signal transduction pathway in NB is different from that of the closely related tumors of ES and PNET.

Blotting, Northern↗
PubMed1997

Outcomes of infants whose mothers are positive for human herpesvirus-6 DNA within the genital tract in early gestation.

It has been reported that HHV-6 (human herpesvirus-6) DNA has been identified within the female genital tract. However, the clinical significance of this finding has been unclear. The clinical outcome of the presence of HHV-6 DNA in the genital tract of pregnant women on their infants was evaluated in the present study. One hundred and ten pregnant women were enrolled. Vaginal swabs were collected between 4 and 8 weeks of gestation and the presence or absence of HHV-6 DNA was evaluated by nested polymerase chain reaction (nPCR). The swabs were cultured to isolate the virus. The women were divided into two groups: HHV-6 DNA-positive, and negative. The outcome variables of the infants of these two groups were statistically estimated at birth and at 1 month of age. Saliva and blood cells were collected from the infants at birth and at 1 month of age and were also evaluated by nPCR. HHV-6 DNA was detected in the vaginal swabs of 28 pregnant women (25.5%), but was not detected in any other samples, including saliva and blood cells from their infants. Virus could not be isolated from any vaginal samples. Any outcome variables were not significantly different between the two groups. The presence of HHV-6 DNA within the genital tract of pregnant women did not affect the health of their infants. It is suggested that HHV-6 transmission to infants through the genital tract of their mothers during pregnancy does not occur, or only very rarely.

Adult↗
PubMed1997

Spontaneous rupture of the liver in an uncomplicated pregnancy.

Spontaneous liver rupture has been reported during pregnancy secondary to severe pregnancy-induced hypertension, eclampsia or syndrome of hemolysis, elevated liver enzymes, and low platelet count (HELLP). Here we report a case diagnosed using CO2 intra-arterial digital subtraction angiography in an uncomplicated pregnancy. A 33-year-old Chinese woman at 39 weeks' gestation underwent a second caesarean delivery. Her pregnancy course had been uneventful. In the immediate postpartum period, she developed clinical signs of hepatic infarction or hematoma. After a blood transfusion and the use of vasoactive agents, her hemodynamic condition became stable. A hepatic angiography was performed before an emergent laparotomy. CO2 intra-arterial digital subtraction angiography revealed a small extravasation that was not found by the conventional method using an ionized medium. This disease should be considered when there occur pain in the upper part of the abdomen and signs of hemorrhagic shock, even in the case of an uncomplicated pregnancy.

Adult↗
PubMed1997

[A case of Tsutsugamushi disease as an imported infection].

Tsutsugamushi disease is widely spread throughout Japan. A case of tsutsugamushi disease was seen in October, 1996. A 64-year-old male developed typical symptoms of tsutsugamushi disease with Rickettsia tsutsugamushi, after he returned to Japan from Cheju Island, Korea. Not only in Japan but also in other Asian countries including Korea, China, Taiwan, and Thailand, tsutsugamushi disease is one of the most important rickettsial diseases carried by ticks or mites. If a traveller returning from an Asian country has symptoms such as high fever, skin eruption, and lymphadenitis, we should suspect that he is suffering from tsutsugamushi disease and should search if he has an eschar on any area of his body. We should not forget that tsutsugamushi disease is an imported disease. Patients of tsutsugamushi disease often have hematological disorders. They are sometimes referred to the hematological section of the hospital. Hematologists should be familiar with this disease.

Anti-Bacterial Agents↗
PubMed1997

Regulation of the Saccharomyces cerevisiae HOG1 mitogen-activated protein kinase by the PTP2 and PTP3 protein tyrosine phosphatases.

In response to increases in extracellular osmolarity, Saccharomyces cerevisiae activates the HOG1 mitogen-activated protein kinase (MAPK) cascade, which is composed of a pair of redundant MAPK kinase kinases, namely, Ssk2p and Ssk22p, the MAPK kinase Pbs2p, and the MAPK Hog1p. Hog1p is activated by Pbs2p through phosphorylation of specific threonine and tyrosine residues. Activated Hog1p is essential for survival of yeast cells at high osmolarity. However, expression of constitutively active mutant kinases, such as those encoded by SSK2deltaN and PBS2(DD), is toxic and results in a lethal level of Hog1p activation. Overexpression of the protein tyrosine phosphatase Ptp2p suppresses the lethality of these mutations by dephosphorylating Hog1p. A catalytically inactive Cys-to-Ser Ptp2p mutant (Ptp2(C/S)p) is tightly bound to tyrosine-phosphorylated Hog1p in vivo. Disruption of PTP2 leads to elevated levels of tyrosine-phosphorylated Hog1p following exposure of cells to high osmolarity. Disruption of both PTP2 and another protein tyrosine phosphatase gene, PTP3, results in constitutive Hog1p tyrosine phosphorylation even in the absence of increased osmolarity. Thus, Ptp2p and Ptp3p are the major phosphatases responsible for the tyrosine dephosphorylation of Hog1p. When catalytically inactive Hog1(K/N)p is expressed in hog1delta cells, it is constitutively tyrosine phosphorylated. In contrast, Hog1(K/N)p, expressed together with wild-type Hog1p, is tyrosine phosphorylated only when cells are exposed to high osmolarity. Thus, the kinase activity of Hog1p is required for its own tyrosine dephosphorylation. Northern blot analyses suggest that Hog1p regulates Ptp2p and/or Ptp3p activity at the posttranscriptional level.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1997

Endoscopic papillary balloon dilatation may preserve sphincter of Oddi function after common bile duct stone management: evaluation from the viewpoint of endoscopic manometry.

BACKGROUND: Endoscopic papillary balloon dilatation (EPBD) has been reported as a safe and effective alternative to endoscopic sphincterotomy in the management of common bile duct (CBD) stones; its effect on papillary function has yet to be elucidated. AIM: To investigate sphincter of Oddi (SO) motility before and after EPBD to determine its effect on SO function. PATIENTS AND METHODS: The papillary function of 10 patients with CBD stones was studied using endoscopic manometry before and one week after EPBD. The manometric studies were repeated one month after EPBD in seven patients. RESULTS: One week after EPBD, CBD pressure, SO peak pressure, SO basal pressure, and SO frequency decreased significantly. One month after EPBD, however, all parameters increased although the increases in SO basal pressure and CBD pressure were not significant. There was no significant difference in values of any parameter before and one month after EPBD. No serious complications occurred. CONCLUSION: These data suggest at least partial recovery of papillary function one month after the procedure. EPBD seems to preserve papillary function in treatment of CBD stones; a longer term follow up study with SO manometry should be performed to clarify the effect of EPBD on SO function.

Aged↗
PubMed1997

Pulsatile compression of the rostral ventrolateral medulla in hypertension.

The rostral ventrolateral medulla (RVLM) has been known to be a major regulating center of sympathetic and cardiovascular activities. An association between essential hypertension and neurovascular compression of the RVLM has been reported in clinical observations, including magnetic resonance imaging (MRI) studies. To reconfirm this relationship, we performed MRI using a high-resolution 512 x 512 matrix in patients with essential and secondary hypertension and in normotensive subjects. The duration of hypertension and the degree of organ damage by hypertension were not significantly different between the two hypertension groups. Neurovascular compression of the RVLM was observed in 74% of the essential hypertension group, and the incidence of compression was significantly higher than in the secondary hypertension group (11%) or in the normotensive group (13%) (P < .01). These results from the clinical studies suggest that neurovascular compression of the RVLM is, at least in part, causally related to essential hypertension. Although blood pressure elevation by pulsatile compression of the RVLM in an experimental baboon model has already been reported, its underlying mechanism is not well known. Accordingly, we performed experiments to investigate whether pulsatile compression of the RVLM would increase arterial pressure and to elucidate the mechanism of the pressor response in rats. Sympathetic nerve activity, arterial pressure, heart rate, and plasma levels of epinephrine and norepinephrine were increased by pulsatile compression of the RVLM. The pressor response was abolished by intravenous treatment with hexamethonium or RVLM injection of kainic acid. In summary, the results from the MRI studies suggest that neurovascular compression of the RVLM is, at least in part, causally related to essential hypertension. This was supported by the results from experimental studies using rats indicating that pulsatile compression of the RVLM increases arterial pressure by enhancing sympathetic outflow.

Animals↗
PubMed1997

Neurovascular compression of the rostral ventrolateral medulla related to essential hypertension.

The rostral ventrolateral medulla (RVLM) is thought to serve as a final common pathway for the integration of central cardiovascular information and to be important for the mediation of central pressor responses. An association between essential hypertension and neurovascular compression of the RVLM has been reported. To confirm this relationship and to quantitatively measure the distances between the RVLM and the neighboring arteries, we performed magnetic resonance imaging using a high-resolution 512x512 matrix and magnetic resonance angiography in 49 subjects (21 patients with essential hypertension, 10 patients with secondary hypertension, and 18 normotensive subjects). One patient with essential hypertension was excluded from the evaluations because of inadequate assessment due to poor images. Neurovascular compression of the RVLM was observed in 15 of 20 (75%) patients with essential hypertension. In contrast, neurovascular compression was observed in only 1 of 10 (10%) patients with secondary hypertension and only 2 of 18 (11%) normotensive subjects. The rate of observed neurovascular compression in the essential hypertension group was significantly higher than that in the secondary hypertension group and the normotensive group (P<.01 for both). The distances between the RVLM and the nearest arteries in the essential hypertension group were significantly shorter than those in the other groups (P<.05 for all). On the other hand, the distances between the surface of the medulla oblongata and the nearest arteries did not differ among these three groups. These results suggest that neurovascular compression of the RVLM, but not of the other regions of the medulla oblongata, is particularly related to essential hypertension.

Adult↗