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Biomedical subjects

Y Sugita

Publications and source records attributed to Y Sugita.

At least 19 recordsLinked to original sources
PubMed1992

Effect of phosphoramidon on big endothelin-2 conversion into endothelin-2 in human renal adenocarcinoma (ACHN) cells. Analysis of endothelin-2 biosynthetic pathway.

The biosynthetic pathway of endothelin (ET)-2 was analyzed in cultured ACHN cells. In the supernatant, we detected three ET-2-related peptides, ET-2, big ET-2(1-38) and big ET-2(22-38). Phosphoramidon decreased the amount of ET-2 and increased that of big ET-2(1-38) dose-dependently. The amount of big ET-2(1-37) did not significantly change. These results suggest that big ET-2 is composed of 38 and not 37 amino acid residues, and that a putative ET-2-converting enzyme (ECE-2) should be classified as a phosphoramidon-sensitive neutral metalloprotease, bearing a resemblance to the putative ET-1-converting enzyme (ECE-1) in endothelial cells.

Adenocarcinoma↗
PubMed1992

Changes in the nature of calcium transport systems on the porcine sperm plasma membrane during epididymal maturation.

Comparative studies of 45Ca(2+)-transport across the plasma membrane were performed using porcine caput, corpus and cauda epididymal sperm. The Ca(2+)-uptake is dependent on the presence of the substrates for respiration and is sensitive to verapamil. The Ca(2+)-efflux is mediated by both Na(+)-dependent and -independent systems. In the immature sperm in caput epididymis, Na(+)-independent efflux is predominant, but it is gradually replaced by Na(+)-dependent efflux during the epididymal transit. The net activity of Ca2+ accumulation into sperm increases with the epididymal maturation.

Animals↗
PubMed1992

Propagation of colour information across borders.

When a part of an image is stabilized on the retina, the part fades to the same colour as its unstabilized surround. The apparent colour of an empty field is therefore assumed to be equal to the colour of its borders. Here, we will show that a similar phenomenon can take place even when the border of a centre field is still visible. A grey square patch with a black frame was surrounded by a coloured background. When the frame had such crossed disparity that the frame appeared in front of the patch, the colour of the patch became perceptually similar to that of the background, indicating that the colour of an empty field is not determined by the colour of its borders alone.

Color Perception↗
PubMed1992

Diagnosis of typhus infection with Rickettsia tsutsugamushi by polymerase chain reaction.

Two sets of oligonucleotide primers were used to amplify the genomic DNA of Rickettsia tsutsugamushi, the causative agent of scrub typhus (tsutsugamushi disease), by the polymerase chain reaction. Each set of primers amplified 538-bp and 109-bp products, representing part of a gene encoding a possible major 58-kDa immunogenic protein, from whole genomic DNA extracted from R. tsutsugamushi strains Karp, Kato, Gilliam, Kuroki and Kawasaki. No amplification was observed from R. sibirica, R. rickettsii, mouse and human genomic DNA. DNA amplification was observed from crude lysates of peripheral whole blood, tissue homogenates and paraffin-embedded skin biopsy sections obtained from patients with scrub typhus disease. Southern blot analysis demonstrated the specificity of the amplified DNA fragments following hybridisation with a DNA probe generated from R. tsutsugamushi strain Karp. By means of this procedure, a rapid and sensitive diagnosis of scrub typhus disease can be made during the acute stage of this infection.

Acute Disease↗
PubMed1992

Modulation of bullous pemphigoid antigen gene expression by gamma-interferon in cultured keratinocytes.

Bullous pemphigoid (BP) is characterized by the production of autoantibodies against BP antigens. gamma-interferon (gamma-IFN), a T-cell lymphokine, is known to enhance the expression of several cell-surface proteins. In this study, keratinocytes were cultured in the presence of gamma-IFN, the expression of BP antigen protein was examined by flow cytometry and BP antigen messenger RNA (mRNA) (encoding 230-kDa protein) was quantified by slot-blot hybridization. The results indicated that BP antigen gene expression by keratinocytes was upregulated by gamma-IFN. This enhancement of gene expression was detected at both the protein and mRNA level, suggesting pretranslational regulation. These results imply the involvement of not only humoral immunity but also cell-mediated immunity in the development of BP.

Animals↗
PubMed1992

Cystine uptake and glutathione level in endothelial cells exposed to oxidative stress.

The uptake of L-cystine into cultured human umbilical vein endothelial cells was Na+ independent and inhibited competitively by glutamate. It is concluded that the uptake of cystine in endothelial cells is mediated by system x-c. The contents of glutathione in endothelial cells decreased when the cells were cultured in cystine-free medium or in glutamate-enriched medium, suggesting that the glutathione level in endothelial cells is regulated by the cystine uptake via system x-c. The uptake rate of cystine increased three times the normal rate when the cells were exposed to H2O2 generated by glucose and glucose oxidase. This increase required protein synthesis. The cystine transport activity was also enhanced when the cells were cocultured with activated polymorphonuclear leukocytes. Intracellular glutathione levels were decreased when the cells were exposed to H2O2 despite an increase in the cystine uptake. The extracellular glutathione levels were increased at that time, suggesting the efflux of glutathione. In endothelial cells, cystine transport activity seems to be involved in the cell defense against oxidative stress.

Cystine↗
PubMed1992

Radiation-induced osteosarcoma of the calvaria--case report.

The authors report a case of radiation-induced calvarial osteosarcoma. A 58-year-old female received subtotal removal of the pituitary adenoma and 5000 rads postoperative irradiation. Seven years later, an osteoblastic osteosarcoma occurred in the frontotemporal region. She received total tumor removal and chemotherapy. However, computed tomography subsequently revealed multiple small lesions at the margin of the bone flap. A chest x-ray film demonstrated lung metastasis. Local recurrence and lung metastasis require careful attention in radiation-induced osteosarcoma patients.

Adenoma↗
PubMed1992

Contralateral development of acute subdural hematoma following surgery for chronic subdural hematoma--case report.

An unusual case of acute subdural hematoma developed after drainage of chronic subdural hematoma in a 71-year-old male. The acute subdural hematoma was located over a membranous layer in the subdural space similar to the outer membrane of the chronic subdural hematoma. Intraoperatively, bleeding from the bridging vein and oozing from the superior sagittal sinus were observed. The membranous layer probably separated from the dura mater following decompression after drainage of the contralateral hematoma, and this separation then damaged the bridging vein and superior sagittal sinus, resulting in the acute subdural hematoma.

Acute Disease↗
PubMed1992

[Intracranial primary malignant lymphoma following Behçet's disease--case report].

We reported a case of intracranial primary malignant lymphoma following Behçet disease treated with colchicine. A 43-year-old female with a past history of oral ulcer and folliculitis visited the Department of Ophthalmology on December, 1990, because of her impaired visual acuity. A diagnosis of uveitis due to incomplete type Behçet disease was made from funduscopic examination and her past history. She had been received 1.0mg/day colchicine for six months in the outpatient clinic. She was referred to our department on August 19, 1991, with nausea and headache. On admission, neurological examination revealed slight right cerebellar ataxia showing dysmetria and dysdiadochokinesis. Computed tomography scan and magnetic resonance images demonstrated a malignant lymphoma in the left cerebellar hemisphere. Stereotaxic biopsy resulted in the B cell type malignant lymphoma (Diffuse large cell type). Galliumscintigraphy, physical examination and peripheral blood examination disclosed no systemic abnormalities. There was a reduction of lymphocyte's response to PHA (phytohemagglutinin) stimulation (1.24). The tuberculin reaction was negative. Colchicine was discontinued and the therapy with radiation and prednisolone (20 mg/day) was started under the diagnosis of intracranial primary malignant lymphoma. She was discharged without any neurological deficits on November 25, 1991. She still suffers from impaired visual acuity, but has no problems in daily life. To our knowledge no intracranial primary malignant lymphoma following Behçet disease has been reported previously. The relationship between Behçet disease treated with colchicine and the occurrence of malignant lymphoma is discussed. In our case we speculated that malignant lymphoma might have occurred in an immunosuppressive state due to administration colchicine.

Adult↗
PubMed1992

[Brain metastasis of lung cancer with Eaton-Lambert syndrome--case report].

A case of brain metastasis of lung cancer with Eaton-Lambert syndrome (ELS) is reported. A 45-year-old male was admitted to the Department of Surgery in Kurume University Hospital on November 13, 1985, complaining of general fatigue. On admission, neurological examination revealed diplopia and fatigue of the extremities. The electromyogram (EMG) showed the waning phenomenon in low frequency repetitive stimulation (2Hz) and the waxing phenomenon in high frequency repetitive stimulation (10Hz, 20Hz). His clinical symptoms, radiological findings and EMG findings demonstrated lung cancer with ELS. Left pulmonary lobectomy with lymphnode dissection of the anterior mediastinum and pulmonary hilus was performed on December 4. Intraoperatively, the tumor was strongly adherent to a medium lymphnode. The patient experienced complete relief symptoms due to ELS. Histological examination disclosed a small cell carcinoma without lymphnode metastasis. He was discharged without any neurological deficits following chemotherapy on February 27, 1986. He was readmitted to the Department of Neurosurgery on August 29, 1986, because of the development of nausea and vomiting. Neurological examination demonstrated no abnormalities except for choked disc in the bilateral ocular fundi. The computed tomography scan revealed a metastatic brain tumor with a mural nodule and cyst. The tumor was totally removed on September 2. Histological examination revealed a typical appearance of small cell carcinoma. He followed a satisfactory postoperative course. He was discharged following radiation therapy on November 2, 1986, and was followed as an outpatient. He has no problem in daily life since then. Though the patient had an expanding metastatic brain tumor from lung cancer after the first operation, he experienced no symptoms due to ELS.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Neoplasms↗
PubMed1992

[Three cases of pulmonary actinomycosis].

Three cases of pulmonary actinomycosis are reported. Case 1 was a 33-year-old man complaining of hemosputum. A large mass lesion was noted in the right upper lobe and surgically resected. Actinomycosis was diagnosed pathologically. The second case was a 41-year-old man with lung abscess. An actinomyces species was cultured by percutaneous aspiration biopsy. He was effectively treated with clindamycin. The third case was a 46-year-old man with a chronic cough and cavitary lesion. Gram staining of sputum revealed sulfur granules. Piperacillin was administered with prompt response. All three cases had dental disease and two had diabetes mellitus. In patients with a mass lesion or those with lung abscess not effectively treated by cephem antibiotics, actinomycosis should be suspected especially when diabetes mellitus and/or dental disease coexists. Adequate treatment may not always require long-term antibiotics.

Actinomycosis↗
PubMed1992

[Atypical leukemia accompanied by vitamin B12 deficiency].

A 76 year old female with atypical leukemia complicated by vitamin B12 deficiency demonstrated marked fluctuation in blast percentage and hemopoiesis over 8 month period. She underwent surgical removal of pancreas head cancer 5.5 years ago. In January 1989 severe pancytopenia and mild increase of bone marrow blast were found. Blood transfusions and inadvertent administration of Vitamin B12 resulted in alleviation of pancytopenia and decrease in blast percentage. Several months later her bone marrow blast exceeded 30%, when serum B12 concentration was below 90 pg/ml. B12 injection and blood transfusion resulted in significant improvement in her hematological condition, but shortly thereafter she died of fulminant hepatitis. Her bone marrow cells showed a polyclonal constitution, as assessed by the RFLP-methylation technique using the PGK gene as a probe. The coexistence of leukemic- and normal clones under Vitamin B12 deficiency conditions and the differing behavior of such clones to B12 supplementation may explain the unusual clinical course observed in this patient.

Aged↗
PubMed1991

Induction of cationic amino acid transport activity in mouse peritoneal macrophages by lipopolysaccharide.

The transport of cationic amino acids has been investigated in mouse peritoneal macrophages cultured in vitro. The transport activity for lysine was rather low in cells cultured for 1 h and increased slightly in cells cultured for 12 h. This increase varied with the serum lot used in the culture medium and was suppressed by polymyxin B, suggesting that the transport activity is induced by endotoxins in the serum. When the macrophages were cultured in the medium containing 1 ng/ml lipopolysaccharide, the transport activity for lysine increased by more than 10-fold. The transport activity for lysine induced by lipopolysaccharide has been characterized. Lysine was transported mainly by a Na(+)-independent, saturable system. The uptake of lysine was potently inhibited by extracellular cationic amino acids, but not by neutral amino acids tested. In addition, transport of lysine showed trans-stimulation. From these results, we have concluded that the transport activity for cationic amino acids is potently induced by lipopolysaccharide and that the characteristics of the induced activity is consistent with those of system y+.

Amino Acids↗
PubMed1991

Purification of bicarbonate-sensitive sperm adenylylcyclase by 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid-affinity chromatography.

Anion transport inhibitors, such as SITS (4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid) and heparin, inhibit reversibly the bicarbonate-sensitive adenylylcyclase of porcine sperm plasma membrane. In the light of this, SITS- and heparin-affinity chromatographies were applied in order to purify sperm adenylylcyclase. SITS-Affi-Gel 102 binds proteins extracted from the porcine cauda epididymal sperm plasma membrane by Lubrol-PX, more selectively than heparin-agarose. However, recovery of adenylylcyclase activity is higher when heparin-agarose is used. The hormone-sensitive liver adenylylcyclase, which is less sensitive to bicarbonate than sperm enzyme, has less affinity for these affinity resins than sperm enzyme. Adenylylcyclase can be purified to apparent homogeneity on two-dimensional gel electrophoresis (isoelectric focusing/sodium dodecyl sulfate-polyacrylamide gel electrophoresis) from the Lubrol-PX extract of the purified sperm plasma membrane by using SITS-affinity chromatography at the first step of the purification followed by preparative isoelectric focusing and gel filtration. The molecular weight and pI of the purified enzyme are 46,300 and 6.9, respectively. The purified enzyme activity is highly dependent on Mn2+. Bicarbonate activates even the purified enzyme both by decreasing Km and by increasing Vmax.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1991

Expression of the mouse macrophage cystine transporter in Xenopus laevis oocytes.

System xc- mediates transport of cystine and glutamate across the mammalian plasma membrane in a Na(+)-independent manner. This transport activity can be induced in mouse peritoneal macrophages during culture by diethylmaleate, a sulfhydryl-reactive agent. We injected mRNA from such macrophages into Xenopus oocytes and demonstrated the expression of System xc-, i.e., a Na(+)-independent, glutamate-inhibitable cysteine transport system. The expressed cystine transport activity depended on the assay temperature, in that cystine uptake measured at 37 degrees C was severalfold higher than that measured at 20 degrees C. Injection of size-fractionated mRNA indicated that the System xc- transporter of the mouse macrophage is encoded by mRNA of 1.5 to 2.9 kb.

Animals↗