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Biomedical subjects

S Yoshida

Publications and source records attributed to S Yoshida.

At least 523 records · Page 29Linked to original sources
PubMed1999

Abdominal cerebrospinal fluid pseudocyst in a severely handicapped patient with hydrocephalus.

We present a case of an abdominal cerebrospinal fluid pseudocyst as a rare complication of a ventriculoperitoneal shunt. The patient is a severely handicapped bedridden spastic quadriplegic with hydrocephalus. He underwent surgical reconstruction of a shunt tube because of shunt disconnection at the age of 12 years. Fever and frequent vomiting developed 2 months after surgery, and abdominal fullness gradually became severe. He was diagnosed as having an abdominal cerebrospinal fluid pseudocyst on abdominal ultrasonography. If a shunt dysfunction is suspected, this type of cyst should also be considered, and abdominal ultrasonography should be performed as one of the screening tests for determining the cause of the shunt dysfunction.

Abdomen↗
PubMed1999

Definitive chemoradiotherapy for T4 and/or M1 lymph node squamous cell carcinoma of the esophagus.

PURPOSE: To investigate the efficacy and feasibility of concurrent chemoradiotherapy for locally advanced carcinoma of the esophagus. PATIENTS AND METHODS: Fifty-four patients with clinically T4 and/or M1 lymph node (LYM) squamous cell carcinoma of the esophagus were enrolled. Patients received protracted infusion of fluorouracil 400 mg/m(2)/24 hours on days 1 to 5 and 8 to 12, 2-hour infusion of cisplatin 40 mg/m(2) on days 1 and 8, and concurrent radiation therapy at a dose of 30 Gy in 15 fractions over 3 weeks. Filgrastim was prophylactically administered to 35 patients. This schedule was repeated twice every 5 weeks, for a total radiation dose of 60 Gy, followed by two courses of fluorouracil (800 mg/m(2)/24 hours for 5 days) and cisplatin (80 mg/m(2) on day 1). RESULTS: There were 21 patients with T4M0 disease, one with T2M1 LYM, 17 with T3M1 LYM, and 15 withT4M1 LYM. Forty-nine patients (91%) completed at least the chemoradiotherapy segment. The 18 patients (33%) who achieved a complete response included nine (25%) of the 36 with T4 disease and nine (50%) of the 18 with non-T4 disease. Major toxicities were leukocytopenia and esophagitis; there were four (7%) treatment-related deaths. Prophylactic filgrastim reduced the incidence of grade 3 or worse leukopenia without improving dose-intensity or response. With a median follow-up duration of 43 months, median survival time was 9 months. The 3-year survival rate was 23%. CONCLUSION: Despite its significant toxicity, this combined modality seemed to have curative potential even in cases of locally advanced carcinoma of the esophagus.

Adult↗
PubMed1999

Two novel cysteine substitutions (C1263R and C1995S) of thyroglobulin cause a defect in intracellular transport of thyroglobulin in patients with congenital goiter and the variant type of adenomatous goiter.

We analyzed the thyroglobulin (Tg) gene of 2 unrelated patients with congenital goiter and the Tg gene of 2 siblings with the variant type of adenomatous goiter. The clinical characteristics of the patients with congenital goiter and the variant type of adenomatous goiter were very similar, except for serum Tg levels, which were less than 15 pmol/L in the patients with congenital goiter, but 117-181 pmol/L in the patients with the variant type of adenomatous goiter (normal, 15-50 pmol/L). The tissue content of Tg in the thyroid glands of all 4 patients was reduced at 0.9-3.8% of total protein (normal, 19-40%). The missense mutation C1263R was detected in the 2 unrelated patients with congenital goiter; the pedigree study showed an autosomal recessive pattern of inheritance. In the 2 siblings with the variant type of adenomatous goiter, the missense mutation C1995S was homozygously detected. In the Tg complementary DNA of 110 normal subjects, the allelic frequencies of the C1263R and C1995S mutations were each less than 0.5%. Also in the normal subjects were detected 35 nucleotide polymorphisms, the insertion of 3 nucleotides, and 1 alternative splicing, each of which was not associated with any specific thyroid disease. From these data, the molecular mechanism of the C1263R and C1995S mutations was elucidated. We first analyzed the carbohydrate residues of C1263R Tg and C1995S Tg. Sensitivity to treatment by endoglycosidase H suggests that C1263R Tg and C1995S Tg were retained in the endoplasmic reticulum (ER). Also, the presence of endoglycosidase H-resistant Tg as well as endoglycosidase H-sensitive Tg in the patients with the variant type of adenomatous goiter suggests that a fraction of C1995S Tg was transported to the Golgi and associated with the mildly increased serum Tg levels. Native PAGE and Western blot analysis with anti-Tg antibody showed that C1263R Tg and C1995S Tg form high mol wt aggregates in the ER. Our results suggest that missense mutations that replace cysteine with either arginine or serine cause an abnormal three-dimensional structure of Tg. Such misfolded Tg polypeptides are retained in the ER as high mol wt aggregates.

Adenoma↗
PubMed1999

Action of a new mammalian DNA polymerase inhibitor, sulfoquinovosyldiacylglycerol.

We found and previously reported a new mammalian DNA polymerase inhibitor from a sea alga, Gigartina tenella, (Ohta K., et al., Chem. Pharm. Bull., 46, 684-686, 1998). It was a new sulfolipid compound that belonged in the class of sulfoquinovosyldiacylglycerol. The biochemical properties have been investigated here. The compound, temporarily designated KM043, potently inhibited the activities of mammalian DNA polymerase alpha(pol. alpha) and DNA polymerase beta(pol. beta) and terminal deoxynucleotidyl transferase (TdT), and moderately, human immunodeficiency virus reverse transcriptase (HIV-RT). KM043 dose-dependently inhibited their activities, and each of their IC50 values was 0.25 microM for pol. alpha, 0.38 microM for TdT, 3.6 microM for pol. beta, or 11.2 microM for HIV-RT, and almost complete inhibition of each was achieved at 1.0 to 2.0 microM for pol. alpha and TdT, 7.5 microM for pol. beta and about 30 microM for HIV-RT. However, the compound did not influence the activities of prokaryotic DNA polymerases such as E. coli DNA polymerase I, and DNA metabolic enzymes like DNase 1. Inhibition of pol. alpha or beta by KM043 was non-competitive with both the DNA template and the substrate deoxythymidine 5'-triphosphate (dTTP). KM043 was weakly cytotoxic to cultured HeLa-S3 cells, and the IC50 value was 80 microM. KM043 could synergistically enhance the cytocidal effect of an anti-cancer chemotherapy agent, bleomycin. In the presence of 50 microM KM043, the effect ratio of (bleomycin plus KM043)/(bleomysin only) decreased from 0.76 to 0.22.

Animals↗
PubMed1999

Synthesis of optically active NC-1800, a therapeutic agent for urinary disturbance.

A new synthetic method for chiral oxazolidinone derivatives, therapeutic agents for treating urinary disturbance, is described. The condensed compound obtained from chiral 1-amino-3-phenyl-2-propanol and 1-phenyl-3-morpholino-1-propanone was reduced with Me4NBH(OAc)3 to give the intermediate, 1-(3-morpholino-1-phenylpropyl)amino-3-phenyl-2-propanol (MAPP) in 34% diastereomeric excess (d.e.). MAPP was converted to an urethane and purified by recrystallization of its methanesulfonate, to afford a single isomer, (2R)-1-[N-[(1S)-3-morpholino-1-phenylpropyl]-N -ethoxycarbonyl]amino-3-phenyl-2-propanol methanesulfonate (4-A. methanesulfonate).

Indicators and Reagents↗
PubMed1999

Purification and characterization of recombinant Mortierella vinacea alpha-galactosidases I and II expressed in Saccharomyces cerevisiae.

The cDNAs coding for Mortierella vinacea alpha-galactosidases I and II were expressed in Saccharomyces cerevisiae under the control of the yeast GAL10 promoter. The recombinant enzymes purified to homogeneity from the culture filtrate were glycosylated, and had properties identical to those of the native enzymes except for improving the heat stability of alpha-galactosidase II and decreasing the specific activities of both enzymes.

Bacterial Proteins↗
PubMed1999

Intraocular neovascularization.

An important character of the eye is transparency, so intraocular neovascularization, which is fragile and likely to result in hemorrhage, would cause a functional disorder of the eye and contribute to loss of vision associated with such diseases as retinopathy of prematurity, diabetic retinopathy, retinal vein occlusion, and age-related macular degeneration. Recently interest in the mechanisms of intraocular neovascularization has increased, and the mechanisms have been gradually elucidated using several in vitro and in vivo angiogenesis models. Blood vessels in the eye are composed of, and surrounded by, various types of cells that produce multiple factors. Neovascularization is regulated by complex interactions among these angiogenic factors, angiostatic factors, and adhesion molecules, and some of these angiogenesis-related molecules have also been suggested as new targets for novel therapeutic agents of intraocular neo-vascularization. This review focuses on in vivo representative angiogenesis models of the corneal pocket model and the model of oxygen-induced retinopathy, and discusses the role of some angiogenesis-related factors and adhesion molecules in intraocular neovascularization.

Animals↗
PubMed1999

Expression of asialoglycoprotein receptor in human fetal liver.

Asialoglycoprotein (ASGP) receptor, which exists in hepatic parenchymal cells, plays important roles in the clearance of desialylated glycoproteins from the circulation. To study the expression of ASGP receptor in human fetal liver, specimens were obtained after therapeutic/spontaneous abortion or at autopsy with informed consent. Reverse transcription polymerase chain reaction and immunohistochemical staining showed that ASGP receptor was present as early as 15 weeks of gestation in human fetal liver. In liver at 15 weeks-gestation it was stained uniformly in cytoplasm as seen in HepG2 cells. As gestation proceed the ASGP receptor was frequently observed on the cell surface and intracellular staining showed a spotted distribution. We conclude that the expression of ASGP receptor is an early event in the developmental process of fetal liver. Furthermore, the distribution of ASGP receptor changes as the liver develops.

Asialoglycoprotein Receptor↗
PubMed1999

Localization of PDK-1 mRNA in the brain of developing and adult rats.

Gene expression for 3-phosphoinositide-dependent protein kinase-1 (PDK-1) in developing and adult rat brains was examined by in situ hybridization histochemistry. In embryonic days, the mRNA was evident throughout the entire neuraxis. The expression remained evident throughout the entire gray matters until postnatal day 7, and thereafter it decreased overall in the mantle and ventricular zones except for the cerebellar Purkinje and granule cell layers, the olfactory and hippocampal neuronal layers. The pattern of this gene expression is similar to those of for protein kinase B and class I phosphoinositide 3-kinases.

3-Phosphoinositide-Dependent Protein Kinases↗
PubMed1999

Does the stomach remain silent after neonatal loss of its original pacemaker?: gastric motility in long-term survivors of neonatal gastric rupture.

Gastric peristaltic contractions are controlled by an intrinsic electrical pacemaker located in the mid-body along the greater curve. This study was undertaken to investigate gastric motility in long-term survivors of neonatal gastric rupture who were surgically deprived of their original pacemaker. Four patients, 1 boy and 3 girls, aged between 6 and 12 years were studied. Physiological activity of the gastric remnant was assessed in terms of electrical as well as peristaltic functions by means of electrogastrography and video-recorded barium swallow study. Electrical and mechanical pacing activities were classified into normogastria or dysrhythmia (brady- or tachygastria) according to their frequencies. In these patients, ectopic pacemakers were found to be arising just distal to the site of resection along the greater curve. Electrophysiologically, one patient was diagnosed as having normogastria, and other 3 patients were found to have dysrhythmia (2, bradygastria; 1, tachygastria) on the basis of electrogastrographic analyses. In two of three patients studied further by fluoroscopy, electrical activity agreed well with peristaltic activity. In one patient, however, electrical tachygastria was associated with peristaltic bradygastria. In conclusion, an ectopic pacemaker arises in the stomach that does not remain silent after neonatal surgical loss of its own pacemaker. Noninvasive electrogastrography seems useful in assessing electrical potentials generated by the ectopic pacemaker.

Barium↗
PubMed1999

Progressive myelopathy caused by dural arteriovenous fistula at the craniocervical junction--case report.

A 68-year-old male presented an unusual dural arteriovenous fistula (AVF) located at the craniocervical junction. Magnetic resonance imaging revealed dilated perimedullary veins around the spinal cord at C-1 and C-2 levels, as well as high intensity signals in the spinal cord on T2-weighted images. Vertebral angiography identified an AVF at the point where the right vertebral artery penetrates the dura. The fistula was a single and direct communication between the vertebral artery and the spinal vein. Surgical interruption of the fistula at its venous side resulted in prompt improvement of both motor and sensory signs and symptoms.

Aged↗
PubMed1999

Studies on spatial orientation and posture control and changes in otolith function due to linear acceleration loading.

Otolith function is directly affected by weightlessness at the time of movement in outer space, and changes occur in the mode of response. It has been known for some time that such changes occur in the posture and gait of astronauts just after they return from a trip into space. It is thought that the cause of these changes is disuse atrophy of the antigravity muscles. However, in the present study, experimental subjects underwent repeated linear acceleration loading over a long period of time, and instability of the head and a decrease in posture control, especially in relation to the gait, were observed for the first time. To date, it has been said that the otolith function has a close relationship with ocular counter rolling. However, when the otolith organ was stimulated, the response was seen to be head instability and an irregular effect on the gait. It is surmised that these findings will facilitate future research into the otolith function under gravity-free conditions.

Acceleration↗
PubMed1999

Comparison between deciduous and permanent incisor teeth in morphology of bovine enamel.

Functional incisor teeth (deciduous and permanent teeth) from Bovidae (14 species) were prepared for scanning electron microscopic observation. Ultrastructural patterns of the enamel layer of deciduous and permanent incisor teeth varied (ex. prisms, arrangement pattern of matrices, and in thickness of enamel layer) in each species. The ultrastructures of prisms in longitudinal sections were classified into three types; A, radial, B, tangential, and C, mix of A and B arrangement enamel; modified Koenigswald's method (1982) in examined species. Type A was found in a large part of permanent and a small part of deciduous incisor teeth, while types B and C were mainly found in the deciduous teeth. These morphological features show the remarkable correlation between permanent and deciduous teeth.

Animals↗
PubMed1999

X-irradiation enhances the expression of Bcl-2 in HL-60 cells: the resulting effects on apoptosis and radiosensitivity.

Although p53 has been shown to directly activate transcriptional bax gene and to inhibit expression of bcl-2 gene during radiation-induced apoptosis, it is poorly understood how the Bcl-2 family changes in p53-deficient cells during radiation-induced apoptosis. The present work describes the effect of X-irradiation on the apoptosis of p53-deficient HL-60 cells as assessed by means of several methods. Apoptosis of HL-60 cells was induced by X-irradiation in a dose- and time-dependent manner. 18 h after 5 Gy irradiation, G2 cells underwent apoptosis, while 15 Gy X-irradiation induced the death of G1/S cells by 6 h. After X-irradiation, expression of Bcl-2 was elevated, while Bax expression was unchanged. We have isolated a clonal HL-60 variant following twice 5 Gy irradiation of HL-XR3 cells. These cells highly expressed Bcl-2 (about 2-fold), showed a reduced activation of caspase-3, and were not only more resistant to X-irradiation-induced apoptosis but also more radioresistant. These results suggest that HL-60 cells may resist apoptosis and radiation by increasing Bcl-2 expression, and that this elevated Bcl-2 expression might be one of the causes of the phenomenon, often seen clinically, that tumor cells gradually acquire radioresistance during fractionated radiation therapy.

Apoptosis↗
PubMed1999

An augmentation of Fas (CD95/APO-1) antigen induced by radiation: flow cytometry analysis of lymphoma and leukemia cell lines.

An augmentation of Fas antigen induced by radiation was examined using flow cytometry. Six cell lines established from lymphomas or leukemias (HD-70, FLAM-76, CML-C-1, CML-C-2, DL-40 and DL-95) were used in this study. Each cell line was distributed to two dishes. The cells in one dish were irradiated at 10 Gy with cobalt-60 gamma rays. The control cells were not irradiated. At 6 h, 24 h, and 48 h after treatment, irradiated and non-irradiated cells of each cell line were stained with fluorescein isocyanate (FITC)-conjugated anti-human Fas antibody, and analyzed with flow cytometry. Mean fluorescence intensity (MFI) values of irradiated or non-irradiated cells were examined. MFI rates (MFI value of irradiated cells/MFI value of non-irradiated cells) of each cell line were calculated at each investigated time point, and an augmentation of the Fas antigen expression with radiation was evaluated. FLAM-76 did not express Fas antigen at any time. An augmented expression of Fas antigen due to irradiation was observed in the other five cell lines. These findings strongly suggest that radiation can augment Fas antigen expression in certain tumor cells. Further studies using Fas ligand or specific anti-Fas antibody are needed.

Antibodies↗