Biomedical subjects

Y Maeda

Publications and source records attributed to Y Maeda.

At least 217 records · Page 12Linked to original sources

PubMed2000

Suppression of the growth/differentiation transition in Dictyostelium development by transient expression of a novel gene, dia1.

In Dictyostelium discoideum Ax-2 cells, a specific checkpoint (PS point) from which cells enter the differentiation phase in response to starvation has been specified in the cell cycle. Using the differential display method, we isolated a novel gene, dia1 (differentiation-associated gene 1), that is specifically expressed in cells differentiating from the PS point. The dia1 mRNA has an open reading frame of 1,368 bp and is deduced to code for a 48.6 kDa protein (DIA1). The DIA1 protein is highly serine-rich and the serine residues are predominantly located in the C-terminal region. After the PSORT II search, the protein is predicted to be GPI-anchored at the plasma membrane. Unexpectedly, dia1 overexpression rather impaired the progression of differentiation, possibly coupled with the reduced expression of early genes such as cAMP receptor1 (car1). The inhibitory effect of dia1 expression on early differentiation was almost completely nullified by externally applied cAMP pulses. In contrast to dia1 overexpression, antisense RNA-mediated dia1 inactivation was found to enhance the initial step of cell differentiation, as exemplified by precocious expression of car1 and other early genes. We discuss the unique structure and function of DIA1 in relation to the cooperative development of cells during the establishment of multicellular organization.

Amino Acid Sequence↗

PubMed2000

Interactions between local anesthetics and Na+ channel inactivation gate peptides in phosphatidylserine suspensions as studied by 1H-NMR spectroscopy.

Interactions between local anesthetics and a sodium channel inactivation gate peptide (Ac-GGQDIFMTEEQK-NH2, MP-1A), which was dissected from the cytoplasmic linker between domains III and IV of the sodium channel alpha-subunit (G1484-K1495 in rat brain type IIA), have been studied by 1H-NMR spectroscopy. Changes in 1H-NMR chemical shifts of the aromatic proton resonances of dibucaine (pH 7.0) and lidocaine (pH 6.0 and 9.0) in phosphatidylserine (PS) suspensions were observed. The effects of substitution of glutamine (F1489Q; MP-2A) or D-phenylalanine (MP-1A') for L-phenylalanine (F1489) in MP-1A and the effects of substitution of neutral amino acid residues for the corresponding acidic amino acid residues (D1487N, MP-1NA; E1492Q, MP-IQEA; E1493Q, MP-IEQA) in MP-1A, on the aromatic 1H-NMR chemical shift changes of dibucaine and lidocaine were also investigated. From these results it was concluded that: the aromatic ring of phenylalanine of MP-1A and the aromatic ring of the cationic form of dibucaine or lidocaine are interacting by pi-pi stacking; the tertiary amine nitrogen of dibucaine is interacting electrostatically with D1487, whereas that of lidocaine is interacting with E1492.

Amino Acid Sequence↗

PubMed2000

Tumor-like splenic extramedullary hematopoiesis in a patient with myelofibrosis.

A 61-year-old woman, who was diagnosed in 1982 as having polycythemia vera, was admitted to our hospital in July 1998 because of a splenic tumor in an enlarged spleen due to myelofibrosis. As it was difficult to identify the etiology of the splenic tumor, partial splenectomy was carried out. The resected tumor proved to be an extremely proliferative lesion as the result of extramedullary hematopoiesis. Since it is difficult to diagnose the etiology of splenic tumor, the collection and analysis of reports of relevant cases may well facilitate diagnosis.

Diagnosis, Differential↗

PubMed2000

Reactivation of human herpesviruses after allogeneic peripheral blood stem cell transplantation and bone marrow transplantation.

Reactivation of latent herpesviruses results in outcomes ranging from asymptomatic shedding of viruses to severe diseases, depending on the immunological competence of the host. Severe and prolonged suppression of cellular and humoral immunity after hematopoietic stem cell transplantation is accompanied by a high incidence of symptomatic recurrent herpesvirus infections. Subclinical reactivation also occurs more frequently than previously expected in transplant recipients. An increasing viral load in the blood detected by an antigenemia assay or PCR and viral shedding in regional fluids have a predictive value for subsequent diseases. Monitoring of viral DNA in the peripheral blood after allogeneic bone marrow transplantation (allo-BMT) reveals unique temporal profiles of detection for each herpesvirus. Recent studies demonstrate that recovery of CD4+ T cells is enhanced within one month after allogeneic peripheral blood stem cell transplantation (allo-PBSCT) compared to allo-BMT. To clarify whether this immunological advantage could affect the reactivation of human herpesvirus (HHV), we monitored the emergence of viral DNA by a nested-double polymerase chain reaction in peripheral blood leukocytes. Detection rates of HHV-6 DNAs which peak at 3-4 weeks post-transplant, were significantly reduced after allo-PBSCT compared to allo-BMT, while those of other herpesviruses which tend to be reactivated later than this period (Epstein-Barr virus and cytomegalovirus) were similar between the two types of transplants. Detection of HHV-6 DNA within the first month after the transplant was associated with delayed platelet engraftment. These results underscore the important role of CD4+ T reconstitution in inhibiting virus reactivation post-transplant.

Bone Marrow Transplantation↗

PubMed2000

Establishment of a myeloid cell line, YM711, characterized by retinoid resistance.

A myeloid cell line (YM711) was established by transfecting exogenous PML/RARalpha cDNA into peripheral blood stem cells. The cells were positive for CD33, CD34, CD38, CD13, CD14, and CD11b. Cytochemical examination revealed YM711 cells to be positive for peroxidase, alpha-naphtyl butyrate esterase, and acid phosphatase as well. Karyotypic analysis showed them to be nearly tetraploid (92 XXYY). Reverse-transcription polymerase chain reaction showed that, although PML/RARalpha mRNA was detected in YM711, these cells could not be differentiated by all-trans retinoic acid (ATRA). We therefore designated the YM711 cell line as being ATRA resistant. Because YM711 expressed multi drug resistance 1 (MDR-1) mRNA and p-glycoprotein cell surface protein, we assessed whether verapamil and ATRA would induce the differentiation of YM711 cells; they did not. An increased expression of cellular retinoic acid-binding protein (CRABP)-II was also detected on YM711 cells compared with that of HL-60. These results suggest that high level of expression of CRABP-II may contribute to be the mechanism of ATRA resistance. This cell line may be useful in evaluating the mechanism of resistance to retinoid.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2000

Correlation between elevated intratumoral thymidine phosphorylase and prognosis of node-positive breast carcinoma undergoing adjuvant doxifluridine treatment.

We determined intratumoral thymidine phosphorylase (dThdPase) activity in 213 patients with T2N0M0 or T2N1M0 breast cancer. After surgery doxifluridine, an intermediate metabolite of capecitabine, and tamoxifen were given by mouth. According to dThdPase activity the examined patients were classified as: A, high activity group; tumors with the activity not less than the mean value and B, low activity group; tumors with activity less than the mean value. Group A had a better prognosis than group B in node-positive patients (disease-free survival, p=0.0446; overall survival, p=0.0788). Intratumoral dThdPase activity might be a useful marker for predicting responsiveness to doxifluridine treatment in the adjuvant setting.

Adult↗

PubMed2000

[Treatment results of VIP (etoposide, ifosfamide and cisplatin) chemotherapy as a first-line therapy in metastatic germ cell tumors].

PURPOSE: We investigated the effectiveness and toxicity of VIP therapy as a first-line chemotherapy for patients with metastatic germ cell tumor. PATIENTS AND METHODS: From March 1994 to October 1997, we treated 16 patients with VIP therapy consisting of etoposide (100 mg/m2), ifosfamide, (1.2 g/m2) and cisplatin (20 mg/m2), all of which were generally given daily for 5 consecutive days every 3 weeks. Of the 16 patients, 6 were classified into a good, 5 into an intermediate, and 5 into a poor prognostic group according to the International Germ Cell Consensus Classification. RESULTS: Thirteen patients (81%) achieved complete response with VIP alone or VIP plus surgery. Three-year survival rate was 100% in good and intermediate prognostic group, while 40% in poor prognostic group. Although all patients had Grade 3 or higher myelosuppression, the treatment was well tolerated and no patient died of treatment-related complications. CONCLUSIONS: VIP appears to be an effective and safe regimen as an induction chemotherapy for good and intermediate risk patients with germ cell tumor. However, more intensive regimen may be necessary for poor-risk patients.

Adult↗

PubMed2000

Endogenously generated nitric oxide by nitric-oxide synthase gene transfer inhibits cellular proliferation.

We investigated whether endothelial nitrite oxide synthase (NOS) gene transfer inhibited cellular proliferation. Endothelial NOS and endothelin type A receptor genes were transferred into 293 cells, a human embryonic kidney cell line, by calcium-phosphate coprecipitation. The cytosolic free Ca(2+) levels ([Ca(2+)](i)) of transfected cells were estimated with fura-2 fluorescence. Thymidine incorporation was increased by endothelin-1 in type A receptor-transfected cells. The endothelial NOS gene transfer did not affect endothelin-1-induced increase in [Ca(2+)](i) of type A receptor-transfected cells, but markedly inhibited mitogen-activated protein kinase and c-fos promoter activities. The endothelial NOS gene transfer also inhibited thymidine incorporation into type A receptor-transfected cells in response to endothelin-1, which was abolished in the presence of the NOS inhibitor N(G)-monomethyl-L-arginine acetate. The endothelin-1-induced increase in cell number was significantly suppressed by endothelial NOS gene transfer as well as by the mitogen-activated protein kinase inhibitor PD98059. These results indicate that endothelial NOS gene transfer inhibits cellular proliferation via inhibition of the mitogen-activated protein kinase cascade.

Calcium↗

PubMed2000

Probable involvement of the 5-hydroxytryptamine(4) receptor in methotrexate-induced delayed emesis in dogs.

Delayed emesis in cancer patients undergoing chemotherapy remains a significant problem. The pathogenesis of delayed emesis is still obscure. It was recently demonstrated that methotrexate (MTX), an anticancer drug, evoked delayed emesis in dogs in a manner similar to its actions in humans. We evaluated the antiemetic activity of FK1052, a potent antagonist for both the 5-hydroxytryptamine (HT)(3) and 5-HT(4) receptors, on delayed emesis induced by MTX in beagle dogs. Animal behavior was recorded for 3 days using a video camera. Delayed emesis lasting up to 72 h was observed in dogs treated with MTX (2.5 mg/kg i.v.), but acute emesis did not occur. The following antiemetics, at the dose that prevents cisplatin-induced acute emesis in dogs, were administered i.v. as multiple injections every 12 h during days 2 to 3. FK1052 (1 and 3.2 mg/kg) significantly reduced the emetic episodes caused by MTX, whereas ondansetron (1 mg/kg), a selective 5-HT(3) receptor antagonist, was not effective. The emetic episodes induced by MTX were also inhibited by another 5-HT(3/4) receptor antagonist, tropisetron (1 mg/kg). CP-122,721 (0. 1 mg/kg), a potent selective tachykinin NK(1) receptor antagonist, significantly reduced the emetic responses to MTX. Copper sulfate-induced emesis in dogs was also prevented by FK1052, tropisetron, and CP-122,721 but not by ondansetron. FK1052, tropisetron, and ondansetron had negligible affinity for the NK(1) receptor at 1 microM. These results suggest that the 5-HT(4) receptor may be in part involved in the production of delayed emesis induced by MTX in dogs and that FK1052 may be a useful drug against both acute and delayed emesis induced by cancer chemotherapy.

Animals↗

PubMed2000

[Varicella-zoster virus infection after hematopoietic stem cell transplantation].

Of 264 patients aged 15 years or more who underwent hematopoietic stem cell transplantation between 1989 and September 1998 at the Tokyo Metropolitan Komagome Hospital, 47 were infected by the varicella-zoster virus (VZV). In 2 patients, visceral disease preceded cutaneous dissemination. One of these patients exhibited gastrointestinal symptoms followed by disseminated skin rash 6 days later. In the other patient, epigastralgia developed and was followed by seizures secondary to meningitis; the appearance of a skin rash 5 days after these initial symptoms yielded the diagnosis. Early diagnosis and treatment of VZV infection are important, especially for patients who present with visceral symptoms suspected to be due to VZV.

Acyclovir↗

PubMed2000

[Standard chemotherapy for gastrointestinal malignancies based on evidence].

It has been said that there is no standard chemotherapy for gastrointestinal malignancies. However, standard guidelines are essential to increase the level of medical treatment, and the death rate from gastrointestinal malignancies is very high in Japan. FAMTX, standard therapy for gastric cancer abroad, cannot be standard in Japan due to its toxicities. A combination of 5-FU and cisplatin (FP) is most commonly used as the the first choice for chemotherapy, but it's regimens vary. For colon cancer, it is said that a combination of 5-FU and Leucovorin (LV) is standard, but CPT-11, made in Japan, is a promising agent. There is no recommended drug for advanced pancreatic cancer, so palliative care or no chemotherapy are also available alternatives.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2000

[Evaluation of paclitaxel and carboplatin in patients with endometrial cancer].

The purpose of this study was to evaluate the combination of paclitaxel and carboplatin in patients with endometrial cancer who have high-risk histopathologic criteria with vessel permeation and low grade, advanced or recurrent disease. The combination of paclitaxel (180 mg/m2 over 3 hours) and carboplatin (dosed at an area under the curve of 5-6) was given intravenously every 3 weeks. Response and toxicity were evaluated according to the Japan Society of Clinical Oncology's response and adverse effect criteria. Eighteen patients were entered in this study and a total of 94 courses were administered. Eleven patients had evaluable lesions. Complete and partial responses were achieved in 5 (45.5%) and 3 (27.3%) patients, respectively. Grade 3 or 4 leukopenia and neutropenia occurred in 49.2% and 90.5% of the patients. G-CSF support was needed in 52.4% of the patients. Only one patient received a platelet transfusion. As a high response rate was obtained, this regimen is considered to be promising treatment for endometrial carcinoma. Prospective comparative study between this combination therapy and the conventional therapy for endometrial carcinoma is warranted.

Adenocarcinoma↗

PubMed2000

[New combination therapies for gastrointestinal cancer].

Recently, cisplation (CDDP) and CPT-11 have joined the other drugs used for gastrointestinal chemotherapy, and the combination of I-leucovorin (I-LV)/5-FU has become available for use in medical treatment in Japan. This enables doctors to make a variety of regimens for gastrointestinal cancers. In this paper, we explain the new combinations, especially LV/5-FU/platinum, CPT-11/CDDP, and LV/5-FU/CPT-11. The combination of 5-FU/LV/CPT-11 has shown a higher antitumor activity than 5-FU/LV alone, with increased progression free survival or time-to-treatment failure. This combination will be considered the new standard regimen for colorectal cancer. It is worthy of note that the combination of UFT/LV provided on equally effective but safe and more convenient oral alternative to the standard i.v. 5-FU/LV regimen for colorectal cancer.

Adenocarcinoma↗

PubMed2000

Extracorporeal shock wave lithotripsy: elimination of densely calcified gallstones and gallstones with calcified rims.

OBJECTIVE: Until now, radiopaque gallstones have been excluded from extracorporeal shock wave lithotripsy (ESWL), because these stones in vivo are less sensitive to the forces that cause disintegration. In Japan there is a higher percentage of patients with radiopaque gallstones than in Western countries. Our purpose in working with patients in Japan was to warrant extensive indication of ESWL to radiopaque gallstones, especially densely calcified stones. DESIGN/METHODS: Retrospective analysis of clinical data. Patients were classified by computed tomography (CT) of stones. Group A consisted of 78 patients whose gallstones were densely calcified (CT attenuation values in Hounsfield units (HU), 473 +/- 323). Group B consisted of 22 patients whose stones had a calcified rim (CT attenuation values, 357 +/- 244). Ninety-eight patients received adjuvant dissolution therapy with ursodeoxycholic acid. Other recommendations, such as a glass of milk at night, were not given to the patients. SETTING: One university hospital and one general hospital. PATIENTS: One hundred consecutive Japanese patients with radiopaque stones in contractile gallbladder (CT attenuation values, > 150 HU, 447 +/- 310, mean +/- SD) were the subjects. With respect to the efficacy of ESWL, a degree of calcification for stones and its relationship with the rates of stone fragmentation and disappearance were assessed. Fragmentation to less than 3 mm in stone diameter was the aim, without limit of shock wave discharges and sessions. RESULTS: After ESWL sessions stones were fragmented successfully in 74 of the 100 patients (57 of the 78 patients in Group A, and 17 of the 22 patients in Group B). The mean number of discharges per patient was 10,435 +/- 8,726. The mean number of discharges for successful stone fragmentation of Group A (9,839 +/- 8,187) was not significantly different from that of Group B (11,376 +/- 6,344). One year after lithotripsy, 60 of the 100 patients were free of stones (45 in Group A, and 15 in Group B). CONCLUSION: It appears that patients with either densely calcified gallstones, or those in whom the stones have a calcified rim, are both suitable candidates for lithotripsy.

Adult↗

PubMed2000

[A case of congenital cystic adenomatoid malformation of the lung in a 4-year-old child].

A case of congenital cystic adenomatoid malformation (CCAM) of the lung is reported. A 3-year-old boy was admitted for elevation of infiltrative shadow in the right lower lung field on a chest X-ray. The clinical diagnosis was emphysematous bullae with inflammation. After 6 months, he had recurrent infected bullae, and was admitted. He received chemotherapy with antibiotics prior to the operation. Right lower lobectomy was performed on February 2, 1998. The resected lung was composed of multiple cysts with thin wall measuring 10-60 mm in diameter. The histological examination of specimen revealed CCAM (Stocker type I), which is rare in this age. The patient has been well for 16 months postoperatively.

Child, Preschool↗

PubMed2000

Successful graft-versus-leukemia effect of second bone marrow transplantation on relapsed leukemia cutis that was refractory to intensive chemotherapy and donor lymphocyte transfusions in a patient with acute monocytic leukemia.

We report a patient with acute monocytic leukemia (AMoL; M5) who received a second bone marrow transplantation (BMT) with graft-versus-leukemia (GVL) effect on relapsed leukemia cutis, which had been refractory to intensive chemotherapy and donor lymphocyte transfusions (DLTs). A 21-year-old woman was diagnosed with AMoL and achieved complete remission after intensive chemotherapy. The patient received a nonmanipulated allogeneic BMT from her HLA-identical father. Skin tumors developed in her upper extremities, chest, and thigh 11 months after BMT. Leukemia cutis was confirmed by skin biopsy. There was no evidence of relapse in bone marrow. The patient received several courses of chemotherapy and DLTs for the skin relapse, but the skin tumors persisted. The patient then received a second BMT from the same donor. On day 80, grade II acute graft-versus-host disease developed, and the remaining skin tumors were eradicated on day 98, most probably because of GVL effect.

Adult↗

PubMed2000

[Capecitabine--a review of its antitumor activity and toxicity in clinical studies].

Capecitabine is a novel fluoropyrimidine carbamate, orally administered and rationally designed to undergo tumor-selective activation. Some studies have been proven it to be safe for outpatient treatment and to have significant antitumor activity in colorectal and breast cancer patients. Randomized trials of patients with advanced colorectal cancer using capecitabine versus Leucovorin (LV).5-FU were studied in two groups. Capecitabine results in both a higher response rate and a more favorable toxicity profile than LV.5-FU. In women aged 55 years or more with breast cancer, capecitabine showed at least comparable efficacy to CMF combination therapy. Capecitabine offers a new effective oral treatment option as a single agent for patients with advanced colorectal or breast cancer.

Antineoplastic Agents↗

PubMed2000

[A clinical study of posttraumatic hydrocephalus].

From 1989 to 1998, 721 patients with head injury were admitted to our department and 22 (3.1%) of them developed posttraumatic hydrocephalus. These patients included 16 males and 6 females, ranging in age from 17 to 86 years (mean age, 66 yrs) with peak incidence in the eighth decade. CT scan on admission immediately after head injury showed subarachnoid hemorrhage (SAH) in 18 cases. The other 4 cases without SAH had once suffered head injuries severe enough to give rise to consciousness disturbance. The typical clinical symptoms of hydrocephalus were observed in only 5 (23%) patients, and in the other 17 cases prolonged or deteriorated of consciousness disturbance were the main symptoms. Hydrocephalus was diagnosed between 1 and 3 months in 15 cases and in 7 cases after 4 months. Clinical improvement has been seen in 17 (77%) cases and marked recovery of consciousness was achieved in 12 cases after V-P shunt, but 5 cases with severe disturbance of consciousness revealed no improvement of clinical signs even after decrease of ventricular size. These results indicate that elderly patients with traumatic SAH should be followed up for at least 4 to 5 months, paying attention to development of hydrocephalus, and V-P shunt would be effective to improve consciousness disturbance in most of the cases.

Adolescent↗