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Biomedical subjects

Y Maeda

Publications and source records attributed to Y Maeda.

At least 343 records · Page 19Linked to original sources
PubMed1998

71-kilodalton heat shock cognate protein acts as a cellular receptor for syncytium formation induced by human T-cell lymphotropic virus type 1.

We previously reported that the region corresponding to amino acids 197 to 216 of the gp46 surface glycoprotein (gp46-197) served as a binding domain for the interaction between gp46 and trypsin-sensitive membrane components of the target cell, leading to syncytium formation induced by human T-cell lymphotropic virus type 1 (HTLV-1)-bearing cells. Our new evidence shows that the 71-kDa heat shock cognate protein (HSC70) acts as a cellular receptor for syncytium formation. Using affinity chromatography with the peptide gp46-197, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, we isolated three components (bands A, B, and C) from MOLT-4 cell lysate which exhibited specific interactions with gp46 and inhibitory activities for syncytium formation induced by HTLV-1-bearing cells. Band A and B components were identified as HSC70 and beta-actin, respectively, through amino acid sequencing by tandem mass spectrometry and immunostaining with specific monoclonal antibodies. Band C is likely to be a nonprotein component, because full activity for syncytium formation was seen after extensive trypsin digestion. Anti-HSC70 monoclonal antibody clearly blocked syncytium formation in a coculture of HTLV-1-bearing cells and indicator cells, whereas no inhibition was seen with anti-beta-actin monoclonal antibody. Furthermore, flow cytometric analysis indicated that anti-HSC70 antibody reacted with MOLT-4 cells. Thus, we propose that HSC70 expressed on the target cell surface acts as a cellular acceptor to gp46 exposed on the HTLV-1-infected cell for syncytium formation, thereby leading to cell-to-cell transmission of HTLV-1.

Amino Acid Sequence↗
PubMed1998

Basic studies on N''-ursodeoxycholyldiethylenetriamine-N,N,N'-triacetic acid for the dissolution of calcified gallstones.

A novel calcium-chelating agent, N"-ursodeoxycholyldiethylenetriamine-N,N,N'-triacetic acid (UDCA-DTTA), was synthesized to study its ability to dissolve calcified gallstones. The chelating activity of the compound was demonstrated by dissolving calcium carbonate in vitro at a high dissolution rate. In the presence of the agent, sliced human gallstone with a composition of more than 50% calcium bilirubinate was thoroughly dissolved, indicating that calcium bilirubinate was dissolved from the gallstone. The ability to dissolve calcium was comparable to that of EDTA. However, the laminar structure of the sliced gallstone did not disappear in the presence of EDTA, whereas the structure disappeared in the presence of UDCA-DTTA. All these results indicate that UDCA-DTTA is an interesting compound as a parent substance for developing a prodrug for an oral or intravenous agent to dissolve calcium-containing gallstones.

Administration, Oral↗
PubMed1998

The average unwinding angle of DNA duplex produced by the binding of chromomycin A3.

The effect of chromomycin A3 binding on the geometry of DNA duplex (plasmid pBR322) has been examined using topoisomerase I relaxation followed by gel electrophoresis. To determine the equilibrium constant of this drug-DNA binding-dissociation reaction in the same concentration range (ca. 10(-5) M) in the same buffer as those for the topoisomerase reaction (at 37 degrees C), fluorescence measurements were made of the same plasmid-drug system, followed by a Scatchard plot and an analysis using McGhee-von Hippel's exclusion site model. The binding constant has been found to be 3.8 x 10(5) M-1 in the particular buffer (buffer-T) at 37 degrees C, and the number of base pairs involved in the site of one chromomycin molecule on the duplex has been found to be 5. It has been concluded that one chromomycin molecule, bound to the duplex, unwinds it by 11.8 +/- 1.1 degrees. In addition, the enthalpy of binding was determined to be 31.81 kJ/mole using a titration calorimeter with a more concentrated (6.2 mM) solution.

Algorithms↗
PubMed1998

Rearing of Plateau pika (Ochotona daurica) captured in Mongolia.

We attempted to rear and breed Plateau pikas (Ochotona daurica) captured in Mongolia in 1994 and 1995. In rearing indoors, though coitus was observed, none of the females became pregnant. In rearing outdoors, males began to make high-pitched, continuous cries and the first offspring (3 newborns) were obtained in June, 1997. The body weight averaged 8.4 g at birth, and 75.8 g at 4 weeks of age. They were weaned at 4 weeks of age. In August the testes, which had descended into the scrotum, atrophied. In September, the atrophied testes returned to the abdominal cavity. These results indicate that breeding of plateau pikas is possible when they are reared outdoors, and they have a specific reproductive season.

Animals↗
PubMed1998

Mutual relation between the cell-cycle progression and prespore differentiation in Dictyostelium development.

In Dictyostelium discoideum Ax-2, the cell-cycle progression from the early aggregate to mound stage has been proposed to have some connection with prespore differentiation. Hereupon, we examined the role of cell-cycle progression during the development on cell differentiation, using two kinds of cell-cycle inhibitors. Nocodazole, an inhibitor of microtubule formation, was found to inhibit greatly cell division around the mound stage as well as during the vegetative growth phase, when applied to exponentially growing Ax-2 cells. Essentially the same inhibition was attained by treatment of starved Ax-2 cells with calyculin A, an inhibitor of serine/threonine protein phosphatases. It is noteworthy that the nocodazole- or calyculin A-treated cells exhibit abnormal morphogenesis to form a stick-like multicellular structure on non-nutrient agar, and also that prespore differentiation as exemplified by the prespore-specific Dp87 gene expression and prespore specific vacuole (PSV) formation was greatly suppressed. In contrast, the differentiation of prestalk (pstA) cells was scarcely affected by the drug treatments. Taken together these results seem to indicate that the cell-cycle progression around the mound stage is important for prespore differentiation.

Animals↗
PubMed1998

Utility and safety of Hickman catheters for venous access after bone marrow transplantation.

Hickman catheters are useful for vascular access after bone marrow transportation because they can handle large volume and allow for easy transfusions and blood drawing through wide double lumens making it easier to case for patients under sterile conditions in a clean room. However, the safety of Hickman catheters as compared to Silastic catheters in marrow transplants has never been discussed. We therefore retrospectively reviewed the complications of two catheters in 71 allogeneic bone marrow transplant recipients between September 1986 and August 1994. The complication and infection rates of Hickman catheters were 0.21 and 0.09 per 100 device-life days, and rate of temperature >38 degrees C during leukocytopenia (<1,000 white blood cells) was 0.18. These rates were not different from those of Silastic catheters suggesting that Hickman catheters are safe and acceptable in marrow transplantation. The benefits and drawbacks of Hickman catheters relevant to catheter choice were also discussed.

Adolescent↗
PubMed1998

Combined brachytherapy and external beam radiotherapy in normal monkey brains--experimental radiation necrosis evaluated by sequential magnetic resonance imaging.

Radiation-induced brain damage was evaluated using sequential magnetic resonance (MR) imaging in monkeys more than 1 year after either brachytherapy or combined brachytherapy and external beam radiotherapy (EBRT). MR images were obtained 1 week, 1 month, 3 months, and subsequently every 3 months after brachytherapy, and the volume of the lesions was measured. In all four monkeys receiving only brachytherapy and three of the four animals receiving combined brachytherapy and EBRT, MR imaging revealed only transient extensive edema 1 week after treatment and ring enhancement, which was maximal 3 months after treatment, surrounding the implantation site. In one of the four animals undergoing combined brachytherapy and EBRT, MR images obtained 9 months after treatment showed an irregularly extending enhanced lesion with edema. MR images obtained 15 months after brachytherapy in this monkey showed the lesion extended into the contralateral hemisphere through the corpus callosum. Necropsy revealed severe radiation necrosis. This animal developed a very similar MR imaging presentation to that often encountered in human brains after combined brachytherapy and EBRT.

Animals↗
PubMed1998

[Renal hemangiopericytoma: report of a case].

A 34-year-old house wife presented with a right renal mass detected by work-up for epigastralgia. The mass located in the right renal sinus was round and approximately 3 cm in diameter. Although the tumor was well enhanced with contrast medium on CT scan, it was hypovascular on the early arterial phase of renal angiography. Translumbar radical nephrectomy was performed on suspicion of the right renal cell carcinoma. The tumor was solid and hard and, the cut surface of the tumor was homogenously colored pale pink. Microscopically it was hemangiopericytoma arising in the renal sinus, composed of well-developed pericytes and capillaries with so-called staghorn configuration, with invasion of hilar renal vein. Immunohistochemically, the hemangiopericytes were strongly positive for CD34, but negative for factor VIII associated antibodies. To our knowledge, the present patient is the 6th case in the Japanese literature and the first case with incidentally detected renal hemangiopericytoma.

Adult↗
PubMed1998

[A juxtaglomerular cell tumor. Analysis of immunohistochemistry, electron microscopy and in situ hybridization].

We present a case of juxtaglomerular cell tumor measuring 8 mm in diameter in the right kidney. The hypertension was cured and plasma renin activity returned to normal level following tumor resection with partial nephrectomy. We studied histopathologic, electron microscopic, and immunohistochemical findings of the tumor. The majority of tumor cells stores renin granules in cytoplasm. In situ hybridization confirmed us that the most tumor cells produce renin. We use the digoxigenin labeled 0.6-kb length RNA probe of human renal renin, the specificity was analyzed by competition assay (1:50).

Adenocarcinoma↗
PubMed1998

[Successful management for chemorefractory testicular cancer with brain and lung metastases. A case report].

This is a report of successful management for a far advanced, chemorefractory testicular cancer patient. A 29-year-old male was referred to our hospital for the treatment of progressive lung metastases with elevated hCG level, which had recurred after complete remission following 3 courses of BEP chemotherapy and progressed after transient partial regression following 2 courses of intensified EP chemotherapy. In addition, a 3 cm in diameter, solitary brain metastasis was detected on CT. First, we performed wedge resection of bilateral pulmonary lower lobe for chemorefractory pulmonary metastases. Histological examination revealed viable embryonal carcinoma identical to the primary one. Thereafter, whole brain irradiation in combination with VIP chemotherapy (etoposide 100 mg/m2, cisplatin 20 mg/m2 and ifosfamide 1200 mg/m2 daily for 5 consecutive days) was carried out to treat brain metastasis. By 2 cycles of VIP therapy and irradiation (36 Gy), partial tumor regression and normalization of hCG level were achieved, leading to salvage surgery of the brain metastasis which histologically proved to be necrosis. Following an additional cycle of VIP therapy, the patient has been free of recurrence 24 months after completion of the treatment.

Adult↗
PubMed1998

[Percutaneous sclerotherapy for chyluria with leg edema: a case report].

A 45-year-old woman with left leg edema was admitted to our hospital because of chyluria from the previous year. Her left leg edema appeared after Caesarean section for her first delivery and hysterectomy at the age of 31. Because microfilaria was not detected, she was diagnosed with postoperative lymphangiomatosis. The instillation of 0.1-0.5% silver nitrate into the renal pelvis was not effective. We however, after percutaneous sclerotherapy to the left inguinal lymph nodes with doxycycline, the chyluria disappeared and her left leg edema improved. Then, the surplus skin of her left lower leg was resected. We considered percutaneous sclerotherapy to be a good procedure for chyluria due to postoperative lymphangiomatosis.

Anti-Bacterial Agents↗
PubMed1998

[Metastatic renal tumor originating from lung cancer: a case report].

A 45-year-old house-wife, who had undergone surgical treatment for lung adenocarcinoma 2 years previously, presented with a left renal mass detected by follow-up CT. During 7 months of observation, it rapidly enlarged from 1 cm to 3 cm in maximum diameter. Although the short doubling time (40 days) suggested that the tumor was metastatic, abdominal urtrasonography, angiography and CT scan did not exclude primary renal cell carcinoma. Left nephrectomy was performed. Histologically, the tumor proved to be metastasis from the previous lung adenocarcinoma. She has been alive with pulmonary recurrence 13 months after nephrectomy. The doubling time of the tumor may be one of the key factors in differentiating a metastatic renal tumor from a primary carcinoma.

Adenocarcinoma↗
PubMed1998

Thiol compounds rescue growth inhibition by retinoic acid on HTLV-I (+) T lymphocytes; possible mechanism of retinoic-acid-induced growth inhibition of adult T-cell leukemia cells.

We demonstrated significant growth inhibition by retinoic acid (RA) of HTLV-I (+) T-cell lines (ATL-2 and HUT102), but not HTLV-I (-) T-cell lines (MOLT-4 and Jurkat). We hypothesized that the mechanism of growth inhibition by RA depends on an imbalance in redox potential. To examine the effect of exogenous thiol compounds for the growth of HTLV-I (+) T-cell lines by RA, HTLV-I (+) T-cell lines were cultured with several thiol compounds (thioredoxin, L-cystine, and GSH), following addition of 13-cis RA or ATRA, respectively, in cultured with thiol free medium. Unexpectedly, thiol compounds alone did not restore growth inhibition of HTLV-I (+) T-cell lines. However, when those cells were preincubated with thiol compounds for 24 hours, no growth inhibition by 13-cis RA or ATRA was observed. These results suggest that thiol compounds are associated strongly with sensitivity to RA of HTLV-I (+) T cells, but not of HTLV-I (-) T cells and that thiol compounds serve an important role on HTLV-I (+) T cells.

Cell Division↗
PubMed1998

[A case of traumatic subacute subdural hematoma presenting symptoms arising from cerebral hemispheric edema].

Traumatic subacute subdural hematoma is a condition in which the major symptoms affecting prognosis most appear in the subacute stage after head trauma, while traumatic acute subdural hematoma is treated conservatively when the symptoms are mild. The cause of the major symptoms occurring in the subacute stage is mostly expansion of the subdural hematoma volume. The authors report a case of traumatic subacute subdural hematoma in which the cause of the major symptoms was cerebral hemispheric edema instead of expansion of the subdural hematoma volume. To our knowledge, only one similar case to the present case has been previously reported. A 44-year-old female fell from the stairs on July 21, 1995 and was suffering from headache. On July 23, she was admitted to our hospital because of generalized convulsion. On admission, she was drowsy but showed no convulsion. Head CT showed an acute subdural hematoma on the right side with a slight midline shift and no other abnormalities. She was treated conservatively because of the mildness of the symptoms and two days later became alert with no symptoms. Thereafter she only complained of occasional headache which was controlled with medicine. On August 3, she suddenly fell into coma. Head CT showed severe cerebral hemispheric edema on the right side without change of the subdural hematoma size. Emergency cerebral angiography showed no definitive abnormalities such as occlusion of the arteries or of the venous sinuses. Craniotomy associated with external decompression was performed. The hematoma was composed of red-brown jelly accompanied with some liquid component and had a thin black-brown outer membrane. While removing the hematoma, bleeding from a vein on the cerebral surface around the sylvian fissure was observed and this location was suspected to be the sources of the bleeding point. Postoperatively, she received steroid and barbiturate therapy associated with moderate hypothermia under hyperventilation. She tolerated this treatment well and left the hospital, on September 26, 1995 with only diplopia during downward gaze. Although the mechanisms of the cerebral hemispheric edema occurring in the subacute stage was unclear, a failure in the cerebral venous circulation arising from compression to the bridging veins, which may be hypoplastic, by the subdural hematoma was suspected to have been the cause.

Adult↗
PubMed1998

[Cancer chemotherapy in patients of advanced age (over 75)].

Generally, elderly patients are excluded from therapeutic trials because of decreased tolerance to chemotherapy. We discussed chemotherapy cancer patients of an advanced age based on our experience of malignant lymphoma and advanced gastric cancer patients over 75 years of age. We found the tendencies for diagnosis at more advanced stages involved many complications, especially 10% of cases have double cancer, and not good performance status in these patients. Some 53 cases of malignant lymphoma were treated with combination chemotherapy including anthracycline, obtained prolongation of survival in responder. On the other hand, 64 cases of advanced gastric cancer were treated with palliative chemotherapy. Some clinical trials have showed that older and younger patients were no different in terms of response, toxicity and overall survival. But these selected elderly patients could be entered in clinical trials, seemed to have to have surprisingly good health, no historical complications and good performance status, in spite of suffering from cancer. Not only chronological age but also the kinds of cancer and performance status are important justification for decisions to limit or withhold treatment.

Aged↗
PubMed1998

[A new device for allergen skin testing].

We have made a new device for allergen skin testing, which can be used easily. It consists of two parts. One, several gears are fixed on a board in a row, and when one gear goes round, other gears also go round simultaneously. A disposable needle is attached to each gear. A semi-spherical hole is made in the lower surface of a disposable needle, and a sharp needle is fixed in, but not at the centre of the hole. The other, small tanks are arranged in a row at the same distance as the gears. When the disposable needles are inserted to the tanks filled with allergen extract, it is hold in a semi-spherical hole by surface tension. The allergen extracts go intradermally, when the needles move semi-circular on a human skin. We performed skin tests to 23 patients with this device, and got satisfactory results as screening tests.

Allergens↗
PubMed1998

[Hemolytic uremic syndrome after bone marrow transplantation].

One hundred and thirteen patients who underwent autologous or allogeneic bone marrow transplantation (BMT) were investigated for the subsequent development of hemolytic uremic syndrome (HUS). HUS developed in seven patients (four males and three females, five acute lymphocytic leukemia (ALL), one acute myelogenous leukemia, one non-Hodgkin's lymphoma) between 36-196 days after BMT. Four patients were recipients of autologous BMT and three were those of allogeneic BMT. Six patients were preconditioned with the regimens including fractionated total body irradiation (TBI). ALL and preconditioning regimen with TBI were suspected to be the risk factors for the development of HUS. Cyclosporin A (CSP) administration was discontinued in three patients who had been given CSP for graft-versus-host disease prophylaxis. Predonisolone was given to the three patients and plasma exchange was performed in one patient. Both hemolytic anemia and thrombocytopenia were resolved in virtually all patients, while creatinine elevation has persisted along with hypertension in one patient.

Adolescent↗