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Biomedical subjects

Y Ohtani

Publications and source records attributed to Y Ohtani.

At least 55 records · Page 3Linked to original sources
PubMed1999

[Combination of 5'-DFUR and MMC for recurrent rectal cancer with pulmonary metastasis].

We report a 68-year-old man with rectal cancer and recurrent pulmonary metastasis treated with concomitant 5'-DFUR + MMC, which resulted in an extreme reduction of the lesion. The initial pulmonary metastases were treated by pneumonectomy, but 32 months later the patient again showed a pulmonary metastasis. Thus, from July 1997, he was treated with 5'-DFUR (800 mg/day) + MMC (4 mg/2 weeks). After 3 months of therapy, the chest CT examination showed an extreme reduction of the pulmonary lesion, and at 5 months the lesion was even smaller. Presently, after 7 months of therapy, the lesion remains stable. His CEA level is 1.0-2.6 ng/ml. After 4 months of treatment he had mild anorexia, which was alleviated by reducing the 5'-DFUR to 600 mg/day. No other adverse reaction was observed; the therapy was safely conducted on an outpatient basis.

Adenocarcinoma↗
PubMed1999

A case report: tumorectomy for brain metastasis of hepatocellular carcinoma.

Described here is a rare case of an operation for brain metastasis of hepatocellular carcinoma (HCC) after hepatectomy. We admitted a 45-year-old male patient complaining chiefly of a visual field disturbance and headaches. He had undergone a hepatectomy due to HCC one year prior to hospitalization. He was diagnosed with a brain metastasis with intratumoral hemorrhage. He underwent a tumorectomy and hemorrhage excision. After the surgery, his neurological symptoms improved, and he was temporarily rehabilitated. The decision to operate in this case could be questionable because the patient already had a pulmonary metastasis. Nevertheless, we concluded that local therapy for such a brain metastatic lesion would be effective in alleviating his discomforts and improving his quality of life as long as the primary lesion was under control.

Brain Neoplasms↗
PubMed1999

A case of gastrointestinal stromal tumor of the stomach.

In a 55-year-old man, a tumor about 3 cm in diameter was detected in the upper abdomen by abdominal ultrasound screening during follow-up of chronic hepatitis C discovered in 1990. There were no symptoms and no abnormalities on physical examination. Tests for tumor markers were negative. By barium meal and gastroscopy, submucosal tumor was found on the lesser curvature of the stomach, with bridging fold in the absence of central ulceration. Biopsy revealed no tumor tissue. Under the diagnosis of submucosal tumor of the stomach, either a leiomyoma or leiomyosarcoma, partial resection of stomach was performed. Direct invasion of the surrounding organs, lymph node metastasis or distant metastasis was not observed grossly in the operation. Histologic examination of the resected specimen revealed proliferation of spindle cells and oval cells in an interlacing pattern. Immunohistochemistry for CD34, vimentin and c-kit protein was strongly positive, while smooth muscle actin, S-100 protein, desmin and p53 protein were negative. The proliferating cell nuclear antigen index was about 50%, while the MIB-1 index was < or = 1%. From these findings, this tumor was diagnosed as a gastrointestinal stromal tumor of the uncommitted type.

Follow-Up Studies↗
PubMed1998

A hyperalgesic effect of intracerebroventricular cytokine-induced neutrophil chemoattractant-1 in the rat paw pressure test.

Cytokine-induced neutrophil chemoattractant-1 (CINC-1) is a member of the chemokine superfamily. The effect of intracerebroventricular (i.c.v) injection of CINC-1 on the mechanical nociceptive threshold in the rat was examined using the paw-pressure test. An i.c.v. injection of CINC-1 at doses of 1 and 10 pg/rat tended to decrease the nociceptive threshold for mechanical stimuli at 15 min after the injection, and significantly lowered the threshold at 30 min. The threshold stayed at these lowered level over 180 min after the injection. Lower (100 fg/rat) and higher (30 and 100 pg/rat, and 1 and 10 ng/rat) doses of CINC-1 had no effect on the mechanical nociceptive threshold. The present results suggest that CINC-1 facilitates mechanical nociception in the central nervous system (CNS).

Animals↗
PubMed1998

Expression of stromal cell-derived factor-1 and CXCR4 chemokine receptor mRNAs in cultured rat glial and neuronal cells.

The expression of the mRNAs for stromal cell-derived factor-1alpha and -1beta (SDF-1alpha and -1beta) and their receptor CXCR4 in cultured rat glial and neuronal cells was examined. SDF-1alpha mRNA was expressed intensely in astrocytes and weakly in neurons, but not in microglia. SDF-1beta mRNA was expressed weakly in these three types of cells. The expressions of SDF-1alpha and -1beta mRNAs in astrocytes were decreased by treatment with LPS (100 ng/ml) for 1-6 h but markedly increased by that for 24-72 h, whereas the expression of SDF-1beta mRNA in microglia was hardly changed by the treatment for 0.5-6 h, and was decreased by that for 24-48 h. The expression of CXCR4 mRNA was observed in astrocytes, microglia and neurons, and was not altered by LPS treatment.

Animals↗
PubMed1998

Localization of fractalkine and CX3CR1 mRNAs in rat brain: does fractalkine play a role in signaling from neuron to microglia?

Localization of the mRNAs for fractalkine, a CX3C chemokine, and for its receptor CX3CR1 was investigated in the rat brain. In situ hybridization study revealed that fractalkine mRNA was dominantly expressed in neuronal cells particularly in the olfactory bulb, cerebral cortex, hippocampus, caudate putamen and nucleus accumbens. In vitro study using enriched neuronal or glial culture supported the dominant expression of fractalkine mRNA in neurons. On the other hand, CX3CR1 mRNA was dominantly expressed in glial cells throughout the whole brain. The in vitro study suggested the cells expressing CX3CR1 mRNA are microglia, not astrocytes or neurons. Fractalkine appears to function as a signal molecule from neuron to microglia.

Amino Acid Sequence↗
PubMed1998

Isolation and characterization of an invertase and its repressor genes from Schizosaccharomyces pombe.

PCR was used to isolate an invertase homolog gene from the fission yeast Schizosaccharomyces pombe. The cloned inv1(+) gene encodes a protein of 581 amino acids with 16 potential asparagine-linked glycosylation sites, and has 39% and 38% identity to the Schwanniomyces occidentalis and Saccharomyces cerevisiae SUC2 invertases. When the inv1(+) gene was disrupted, S. pombe strains lacked detectable invertase activity. This result showed that the inv1(+) gene encodes only one active invertase in S. pombe cells. The transcription of inv1(+) is repressed in the presence of glucose. The transcription of inv1(+) was not affected in cyr1Delta strain which lacks adenylate cyclase activity, unlike transcription of S. pombe fbp1(+) gene. We have identified an S. pombe gene (scr1(+)) that encodes a homolog of the Aspergillus nidulans CREA which is required for glucose repression of the glyconeogenic pathway. Although the deletion of scr1(+) did not influence the transcription of fbp1(+) gene, glucose repression of the inv1(+) gene was severely affected. These results showed that glucose repression of inv1(+) gene is dependent on scr1(+) gene, and S. pombe cAMP signalling pathway may not be essential for glucose repression of inv1(+) gene.

Amino Acid Sequence↗
PubMed1998

Motion assimilation for expansion/contraction and rotation and its spatial properties.

In a two-frame apparent motion display, a test grating was displaced horizontally or vertically in the presence of an inducer of which component gratings made up expanding/contracting or rotational motion as a whole. In the first experiment, we demonstrated that motion assimilation did occur for the test accompanied by the two-dimensional motion of the inducer. In the second experiment, we showed that the spatial limit of motion assimilation for expansion/contraction or rotation was large, extending over at least a visual angle of 14-21 deg in diameter, but spatial summation did not occur within the limit. The results were discussed in terms of the interaction between local motion detectors and higher-order detectors which monitor global motion of the whole stimulus pattern.

Humans↗
PubMed1998

An alternatively spliced gene encoding a Y-box protein showing maternal expression and tissue-specific zygotic expression in the ascidian embryo.

An ascidian Y-box protein gene was cloned, designated as CiYB, which consists of a highly conserved cold shock domain and an auxiliary tail domain with alternating modules of acidic and basic amino acids. CiYB is a single copy gene in the ascidian genome. During oogenesis and early development, CiYB produces three different transcripts (CiYB1, CiYB2 and CiYB3) by alternate splicing. CiYB1 and CiYB2 were expressed during oogenesis, suggesting that they are recruited into maternal ribonucleoprotein particles. According to gel mobility shift assay, the CiYB1 protein has the ability to bind RNA. The sequence preference of RNA binding is similar to that of the Xenopus Y-box protein (FRGY2), which is a major component of the maternal messenger ribonucleoprotein particles (mRNP) in the oocyte. These results suggest that the ascidian Y-box protein may have an important role for masking and translational regulation of maternal mRNA. Furthermore, CiYB1, CiYB2 and CiYB3 were expressed zygotically in a tissue restricted manner. CiYB1 was expressed specifically in muscle precursor blastomeres and tail muscle cells suggesting its important role in muscle differentiation.

Age Factors↗
PubMed1998

Low levels of apoptosis and proliferative activity in colorectal villous tumors: comparison with tubular tumors.

In order to clarify the cell kinetics of colorectal villous tumors (VT), 21 villous adenomatous areas and 12 carcinomatous areas within villous adenomas were investigated for proliferative activity and apoptosis and compared with a series of 41 tubular tumors (TT), demonstrating elements of intramucosal carcinomas as well as tubular adenomas (so-called carcinoma in tubular adenoma). Proliferation was estimated in terms of Ki-67 labeling indices and mitotic indices, and apoptosis was assessed by DNA nick-end labeling to give apoptotic indices. Apoptotic indices of villous adenomatous and carcinomatous regions were significantly lower than the values for their tubular counterparts. Ki-67 labeling indices were also significantly lower for adenoma components. Apoptotic indices, Ki-67 labeling indices and mitotic indices increased with atypia raised in tubular adenoma components. Correlations of mitotic indices with apoptotic indices, Ki-67 labeling indices with apoptotic indices and mitotic indices with Ki-67 labeling indices were found for each villous tumor group and tubular tumor group, and the apoptosis and proliferation ratios for villous tumors were relatively low, suggesting a tendency for greater growth due to less cell deletion. Although this is only one of the biological features of villous tumor groups, it might play a major role in generation of malignancy.

Adenocarcinoma↗
PubMed1998

Development of diaphragmatic lymphatics: the process of their direct connection to the peritoneal cavity.

The development of the lymphatic system in the rat diaphragm was studied from embryonic day 16 to 25 weeks after birth by histochemistry for 5'-nucleotidase, scanning electron microscopy of KOH-treated or intact tissues, and transmission electron microscopy of thin sections. On embryonic day 16, distinct lymphatics were noted in the subpleural space of the diaphragm periphery. The endothelial cells at this stage contained an abundance of rough endoplasmic reticulum, a developed Golgi apparatus and mitochondria, and fewer pinocytotic vesicles than those in adults. The subpleural lymphatics subsequently increased and formed a polygonal network. They possessed many valves, and by postnatal week 6, some thick collecting lymphatics became endowed with smooth muscle cells. On embryonic day 19, some lymphatics appeared in the subperitoneal space. They extended centripetally and had many lateral projections that subsequently became elongated and connected with those from adjacent lymphatics, thus forming a lattice-like network. During the early postnatal days, the subperitoneal lymphatics projected many bulges that subsequently became elongated, and came into contact with the pores among the mesothelial cells, thus forming lymphatic stomata connecting the lymphatic lacunae to the peritoneal cavity. The lymphatic stomata increased until postnatal week 10. The results show that lymphatics appear as early as embryonic day 16 in the subpleural space of the diaphragm periphery, and develop with age by sprouting to form networks in both the subpleural and the subperitoneal spaces, and that the direct connection of the lymphatic lacunae to the peritoneal cavity is formed after birth.

Animals↗
PubMed1998

Lymphatics of the rat mammary gland during virgin, pregnant, lactating and post-weaning periods.

The distribution and ultrastructure of the lymphatics of the rat mammary gland in virgin, pregnant, lactating and post-weaning periods were examined by enzyme-histochemistry for 5'-nucleotidase (5'-Nase) and transmission electron microscopy. Enzyme-histochemistry for 5'-Nase stained lymphatics in dark brown. In the lactating period, lymphatics abounded in the interlobular connective tissues, but in other periods they were few. The interlobular lymphatics drained into collecting lymphatics running along the mammary ducts. Gaps between lymphatic endothelial cells were significantly wider in lactating period than in other periods, while both number and area of vesicles in the lymphatic endothelial cells were significantly larger in the virgin period than in other periods. In the pregnant and lactating period, the lymphatics contained many lymphocytes and lipid droplets. The results show that during lactating period, the interlobular lymphatics increase and that gaps between lymphatic endothelial cells serve as a major route through which tissue fluids and particulate matters enter the lymphatics, while vesicles seem to be main trans-endothelial transport route during the virgin period. The results will provide basic information for our next investigation on lymphangiogenesis in association with breast cancer.

5'-Nucleotidase↗
PubMed1998

[Procainamide-induced lupus in a patient with bilateral pleural effusion].

A 70-year-old physician was admitted to our hospital because of bilateral pleural effusion and left-sided chest pain on deep inspiration. On admission, the APTT was prolonged and was not corrected with a 1:1 mixture of normal plasma. Results of serological examinations included a positive lupus-anticoagulant test and a positive ANA test at a titer of 1:1,280 in a homogeneous pattern. The patient's age, sex, symptoms, signs, and laboratory results all argued against the diagnosis of SLE except for ANA and lupus anticoagulant test. Because procainamide had been prescribed (250 mg every 6 h) for premature ventricular contractions for eight years before admission, procainamide-induced lupus was suspected. Procainamide was discontinued. Chest pain persisted and tests for c-reactive protein were positive. Prednisolone was administered. Procainamide induced lupus was diagnosed, because anti-histone H 2 A-H 2 B complex antibodies were high by enzyme-linked immunosorbent assay, and IgM-class anti-histone antibodies were found in response to H1, H 2 B and H 2 A-H 2 B complex (immunoblotting), which suggested the drug induced lupus. There are only a few reports of drug induced lupus in which the lupus-anticoagulant test was positive and prednisolone was indicated. The measurements of anti-histone antibodies and of expression of anti-histone antibodies were useful in distinguishing drug-induced lupus from SLE.

Aged↗
PubMed1998

[A sibling of delayed post-anoxic encephalopathy after strangulation].

A sibling of three year old girl and a year old boy, showed delayed post-anoxic encephlopathy after strangulation. After three days of the accident, the girl developed tetraplegia and choreo-athetosis. Her brother also developed choreo-athetosis two weeks after strangulation. T2 weighted MRI revealed a high signal intensity in the bilateral putamen and caudate nucleus. After hyperbaric oxygen therapy for two months, their symptoms diminished. We hypothesize that the functional damage of the neurons occurred in the bilateral basal ganglia as delayed neuronal death because of their vulnerability and peculiarity of the local circulation. Hyperbaric oxygen therapy may be effective in rescuing the neurons from hypoxia.

Asphyxia↗
PubMed1997

Anisotropy for direction discrimination in a two-frame apparent motion display.

Direction discrimination (upward/downward or left/right) for a Gabor patch in a two-frame motion display was measured as a function of the inter-frame displacement size of the component grating with the stimulus position (center, left, right, upper and lower visual fields) as a parameter. The results showed that, for vertical motion in the center, left, right and lower visual fields, the observers saw downward motion more frequently than upward motion, whereas for vertical motion in the upper field and for horizontal motion, no preference for one of the two opposite directions was obtained. Human motion vision is anisotropic in the lower half of the visual field.

Discrimination, Psychological↗
PubMed1997

Dependencies of motion assimilation and motion contrast on spatial properties of stimuli: spatial-frequency nonselective and selective interactions between local motion detectors.

Two sets of experiments were carried out to examine dependencies of two types of induced motion (motion assimilation and motion contrast) on spatial properties of stimuli in terms of spatial-frequency tuning of local motion detectors. In the first set, the magnitudes of motion assimilation and motion contrast for a sinusoidal grating were measured at a function of the spatial frequency of the inducing gratings, with the spatial frequency of the test grating as a parameter. In the second set, the magnitudes were measured as a function of the height of the inducing gratings with the spatial frequencies of the test and the inducing gratings as parameters. For motion assimilation, the magnitude was characterized by a low-pass function of the spatial frequency of the inducing gratings, and the critical height of the inducing gratings, which demarcates the extent of the spatial pooling, varied systematically depending on the spatial frequency of the inducing gratings. For motion contrast, on the other hand, the magnitude was characterized by a hand-pass function, and the critical height depended on the frequency of the test grating. These results suggest that motion assimilation is mediated by the spatial-frequency nonselective interaction between the local detectors, in which the motion signals of the detectors tuned to different spatial frequencies are integrated with each other. Motion contrast is mediated by the spatial-frequency selective interaction, in which the motion signals of the local detectors tuned to the same or similar spatial frequencies are compared and differentiated.

Contrast Sensitivity↗
PubMed1997

Vacuolar protein sorting in fission yeast: cloning, biosynthesis, transport, and processing of carboxypeptidase Y from Schizosaccharomyces pombe.

PCR was used to isolate a carboxypeptidase Y (CPY) homolog gene from the fission yeast Schizosaccharomyces pombe. The cloned S. pombe cpy1+ gene has a single open reading frame, which encodes 950 amino acids with one potential N-glycosylation site. It appears to be synthesized as an inactive pre-pro protein that likely undergoes processing following translocation into appropriate intracellular organelles. The C-terminal mature region is highly conserved in other serine carboxypeptidases. In contrast, the N-terminal pro region containing the vacuolar sorting signal in CPY from Saccharomyces cerevisiae shows fewer identical residues. The pro region contains two unusual repeating sequences; repeating sequence I consists of seven contiguous repeating segments of 13 amino acids each, and repeating sequence II consists of seven contiguous repeating segments of 9 amino acids each. Pulse-chase radiolabeling analysis revealed that Cpy1p was initially synthesized in a 110-kDa pro-precursor form and via the 51-kDa single-polypeptide-chain intermediate form which has had its pro segment removed is finally converted to a heterodimer, the mature form, which is detected as a 32-kDa protein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions. Like S. cerevisiae CPY, S. pombe Cpy1p does not require the N-linked oligosaccharide moiety for vacuolar delivery. To investigate the vacuolar sorting signal of S. pombe Cpy1p, we have constructed cpy1+-SUC2 gene fusions that direct the synthesis of hybrid proteins consisting of N-terminal segments of various lengths of S. pombe Cpy1p fused to the secreted enzyme S. cerevisiae invertase. The N-terminal 478 amino acids of Cpy1 are sufficient to direct delivery of a Cpy1-Inv hybrid protein to the vacuole. These results showed that the pro peptide of Cpy1 contains the putative vacuolar sorting signal.

Base Sequence↗