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Biomedical subjects

T Ogata

Publications and source records attributed to T Ogata.

At least 199 records · Page 11Linked to original sources
PubMed1996

Mental retardation in a boy with an interstitial deletion at Xp22.3 involving STS, KAL1, and OA1: implication for the MRX locus.

Although genotype-phenotype correlations in male patients with various types of nullisomy for Xp22.3 have assigned a locus for X-linked mental retardation (MRX) to an approximately 3-Mb region between DXS31 and STS, the precise location has not been determined. In this paper, we describe a 14 7/12 year old Japanese boy with mental retardation and an interstitial deletion at Xp22.3 involving STS, KAL1, and OA1, and compare the deletion map with that of previously reported three familial male patients with low-normal intelligence and a similar interstitial deletion at Xp22.3. The results suggest that the MRX gene is further localized to the roughly 1.5-Mb region between DXS1060 and DXS1139.

Eye Proteins↗
PubMed1996

A panel of radiation hybrids defining the 7q31-q32 region of human chromosome 7.

Mouse A9 cells containing human chromosome 7 tagged with pSV2neo were irradiated with X-rays and fused to A9 cells to isolate G418-resistant clones. From these clones, we selected radiation hybrids that contained 10-40 Mb of human DNA apparently at a single site of their genome by FISH analysis using human repetitive sequences as a probe. Then we made a panel of hybrids that contained various fragments of the 7q31-q32 region and cover its entire region altogether by PCR with STS markers of human chromosome 7. This panel is useful in chromosome transfer experiments since the dominant selective marker neo gene is attached to human DNA.

Animals↗
PubMed1996

A Case Reprot of Lactating Adenoma of the Breast and Review of the literatures in Japan.

We experienced a rare case of lactating adenoma in the mammary gland of a pregnant woman. A 21-year-old pregnant woman visited our clinic with a chief complaint of left mammary gland tumor. Based on palpation, mammograms and echograms, fibroadenoma or phyllodes tumor was diagnosed and enucleation was performed at the time of biopsy. The histopathological diagnosis was lactating adenoma.

Journal Article↗
PubMed1996

Preoperative radiotherapy and surgery for advanced thymoma with invasion to the great vessels.

From 1983 to 1994, 12 advanced thymomas with invasion to the great vessels were initially treated by irradiation (mean dose, 18.3 Gy) and subsequent surgical resection. In nine patients, complete resection was possible by concomitant resection of the surrounding tissues, mainly pericardium and/or brachiocephalic vein. Histologically, all tumors showed prominent fibrosis. Ten patients also received postoperative radiotherapy (mean dose, 42.3 Gy). Tumor-related deaths occurred in only two patients; one who did not receive postoperative irradiation 21 months and one who had viable cells at the surgical margin 10 months after operation. However, there were also 2 patients who died of respiratory failure due to operation and/or irradiation, one 45 days and the other 7 years after the treatment. Preoperative radiotherapy could facilitate complete resection of the advanced thymomas. The prognosis of the patients treated with preoperative radiotherapy seemed fair if followed by adequate resection and subsequent irradiation.

Adult↗
PubMed1996

Ultra-high-resolution scanning electron microscopy of the continuity of cytoplasmic and luminal membranes in frog oxyntic cells.

BACKGROUND: Despite numerous previous studies, the presumed continuity of the luminal and tubulovesicular membranes in frog oxyntic (oxyntico-peptic) cells remains to be convincingly demonstrated. This study was undertaken to clarify this question by ultra-high-resolution scanning electron microscopy of specially prepared frog stomach specimens before and during histamine stimulation. METHODS: Fasted Japanese meadow frogs stimulated with histamine were used. Oxyntic cell cytoplasmic matrix was removed by the aldehyde-osmium-DMSO-osmium maceration procedure and impregnated with osmium-hydrazine. Specimens were examined without metal coating. RESULTS: In the resting oxyntic cell, the luminal membrane had closely packed surface folds forming a rather flat surface with a few short microvilli. In the cytoplasm, flattened 200-500 nm vesicles were interconnected by numerous slender 20-60 nm tubules forming the tubulovesicular network. Occasional slender tubular branches were found in continuity with the luminal membrane. After histamine stimulation, the number and length of microvilli and surface folds increased, whereas the tubulovesicular membrane system decreased. Sites of clear continuity between the luminal and tubulovesicular membranes were not abundant but were clearly demonstrated in histamine-stimulated oxyntic cells. The small size of the tubules connecting the tubulovesicular system to the plasma membrane renders this observation by transmission electron microscopy very difficult. In these specimens, the clear continuity of the tubulovesicular network to the luminal plasma membrane became more evident. CONCLUSIONS: This study confirms previous findings of increased luminal membrane and depletion of the tubulovesicle system. The demonstration of continuity between these two compartments in our SEM preparations supports the hypothesis of direct transfer of tubulovesicular membrane to oxyntic cell luminal secretory membrane.

Animals↗
PubMed1996

Role of aspartate in ischemic spinal cord damage.

To study the potentially different roles of the excitatory amino acids glutamate and aspartate in the development of ischemic injury of the spinal cord, we measured their release from cultured neurons and glial cells under ischemic conditions. We also examined changes in intracellular Ca2+ concentration and the damage elicited in cultured neurons by glutamate and aspartate. Hypoxic-hypoglycemic treatment (in vitro ischemia) elicited a rapid release of the excitatory amino acids from cultured spinal cord neurons and glial cells, but the release was greater from glial cells than from neurons. The ischemia-induced glutamate release from glial cells was transient; the aspartate release lasted longer, although the peak level was smaller than that of glutamate. In cultured neurons, a remarkable elevation in intracellular Ca2+ concentration was induced by glutamate but not by a lower concentration (10 microM) of aspartate, which is below the neurotoxic dose. At the higher concentration (100 microM), both excitatory amino acids induced a marked elevation in intracellular Ca2+ concentration and neuronal death. These results indicate that aspartate is less potent than glutamate in eliciting excitatory neurotransmission under normal physiological conditions. However, under pathological conditions such as ischemia, the increased release of aspartate from glial cells may add to the damage to neighboring neurons.

Animals↗
PubMed1996

Dynamic electron spin resonance (ESR) imaging of the distribution of spin labeled dextran in a mouse.

The nitroxide group 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) was covalently bound to a dextran via an N-acetamido linkage to produce a novel spin probe, TEMPO-dextran (TEMPO-DX), which circulates for long time periods in an animal without metabolic degradation. TEMPO-DX was stable in mice, while small TEMPO analogs quickly disappeared after administration. Since dextran was reduced somewhat in size during synthesis, the resultant spin-labeled dextran could be excreted through the kidney. A strong L-band electron spin resonance signal was obtained shortly after intravenous administration of TEMPO-DX into the tail vein of a mouse, from which three-dimensional images of specific organs were calculated. The signal was found to persist for well over 1 h.

Animals↗
PubMed1996

Coarctation of the aorta and renal hypoplasia in a boy with Turner/Noonan surface anomalies and a 46,XY karyotype: a clinical model for the possible impairment of a putative lymphogenic gene(s) for Turner somatic stigmata.

This paper describes a 12-year-old Japanese boy with coarctation of the aorta, renal hypoplasia, Turner/Noonan surface anomalies, and a 46,XY karyotype. Although the patient might represent an exceptional case of Noonan syndrome, the combination of the somatic stigmata appears to be consistent with a mutation of the putative lymphogenic gene(s) for Turner somatic stigmata.

Aortic Coarctation↗
PubMed1996

A case of skeletal dysplasia with advanced carpal ossification and "monkey wrench" appearance of the femora: mild Desbuquois dysplasia?

UNLABELLED: We report on a 14-year-old Japanese boy with radiographic features resembling those of Desbuquois dysplasia, including advanced carpal ossification, a "monkey wrench" appearance of the proximal femora, mild spondylar dysplasia, and generalized osteopenia. In contrast to the hitherto known patients with this disorder, however, his birth length was normal, and his short stature, which became apparent postnatally, was much milder than that of the previously reported cases (approximately -5 SD of average), and the joint laxity was more subtle. In addition, facial dysmorphism was absent, as were radial deviation of the second fingers and thoracolumbar kyphoscoliosis. CONCLUSION: The present patient may represent the mildest end of the variable phenotypic manifestation of the recently described Desbuquois dysplasia.

Adolescent↗
PubMed1996

Occurrence of tetrodotoxin in Alexandrium tamarense, a causative dinoflagellate of paralytic shellfish poisoning.

A significant amount of tetrodotoxin was identified in the cultured cells of Alexandrium tamarense, a causative dinoflagellate of paralytic shellfish poisoning. This result supports the hypothesis that both tetrodotoxin and paralytic shellfish toxins can be detected in organisms which possess either of them, although their proportion is different individually. The present result also supports our previous finding that A. tamarense is the origin of tetrodotoxin detected in the highly toxic scallop Patinopecten yessoensis during the bloom of A. tamarense.

Animals↗
PubMed1996

A spatiotemporal study on the distribution of intraperitoneally injected nitroxide radical in the rat head using an in vivo ESR imaging system.

We have developed a rapid-scan in vivo electron spin resonance (ESR) imaging system operating at 700 MHz based on an air-cored two-coil Helmholtz designed resistive magnet. Using this system, we performed ESR-CT for the intraperitoneally injected nitroxide radical, 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl, in the rat head. The imaging data were collected over the time course range from 5 to 47 min after injection at an interval of 3 min and a series of ESR-CT images were reconstructed at the same slice plane (1 cm anterior to interaural line). The series of ESR-CT images thus obtained by rapid scans provided detailed spatiotemporal information on the distribution of the injected nitroxide radical in the rat head. The brain was imaged as a nitroxide-deficient area while the blood vessels and/or extracranium tissues as a nitroxide-rich area. During periods when high intensities of ESR signals were maintained, spots of nitroxide-accumulation were imaged at the central part of the brain. The spots were assigned to the middle sized blood vessels in the brain.

Animals↗
PubMed1996

P-glycoprotein-mediated acquired multidrug resistance of human lung cancer cells in vivo.

We examined whether the increased expression of P-glycoprotein (P-gp) encoded by the human multidrug resistance gene MDR1 is related to the acquired multidrug resistance of lung cancer in vivo. We estimated the chemosensitivity of lung cancer xenografts (LC-6, adenocarcinoma; Lu-24, small-cell cancer) by calculation of relative tumour growth (T/C%, treated/control) in vivo, based on statistical significance determined by the Mann-Whitney U test (P < 0.01, one-sided). MDR1 gene expression levels were evaluated by reverse transcription-polymerase chain reaction (RT-PCR) assay. P-gp production and P-gp localisation were examined by Western blotting and by immunohistochemical analysis respectively. LC-6 and Lu-24 were initially sensitive to both vincristine (VCR, 1.6 mg kg-1: LC-6, 45%; Lu-24, 39%) and doxorubicin (DOX, 12 mg kg-1: LC-6, 26%; Lu-24, 27%) in vivo. VCR-resistant variants (LC-6R, 66% and Lu-24R, 68%) selected with VCR (0.4 mg kg-1, x 9) significantly acquired cross-resistance to DOX (LC-6R, 55% and Lu-24R, 55% respectively). RT-PCR assay showed increased levels of MDR1 expression in LC-6R and Lu-24R with stable MDR1 expression levels. P-gp expression levels were elevated, and the percentage of P-gp-positive tumour cells increased in both LC-6R and Lu-24R. These results suggest that P-gp/MDR1 overexpression is related to acquired multidrug resistance in lung cancer in vivo.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Comparison of mucosal microvasculature between the proximal and distal human colon.

The microcirculation of the human colon with special reference to the differences in microvascular architecture between the proximal and distal colon was studied by scanning electron microscopy with vascular corrosion casting technique. The subsurface capillary networks of the ascending colon were honeycomb-like and multi-layered, with an average number of capillary layers per capillary loop of 3.28 +/- 1.10 (mean +/- SD). Whereas, those of the sigmoid colon were almost single-layered, and the average number of capillary layers was 1.19 +/- 0.39. In the cross-section of vascular casts of both parts of the colon, the ascending capillaries originating from the submucosal arterioles ascended into the mucosal layer and joined into the subsurface capillary networks, which drained into the collecting venules near the surface. The mean diameter of the collecting venules of the ascending and the sigmoid colon was 29.3 +/- 6.41 microns and 19.48 +/- 2.23 microns, respectively. From these findings, it is speculated that the multi-layered capillary networks of the proximal colon are closely related to the greater water absorption and electrolyte transport activities compared to those of the distal colon.

Aged↗
PubMed1996

Sex determining gene on the X chromosome short arm: dosage sensitive sex reversal.

The present review article summarizes current knowledge concerning the sex determining gene on Xp21, termed DSS (dosage sensitive sex reversal). The presence of DSS has been based on the finding that, in the presence of SRY, partial active Xp duplications encompassing the middle part of Xp result in sex reversal, whereas those of the distal or proximal part of Xp permit male sex development. Because Klinefelter patients develop as males, it is believed that DSS is normally subject to X-inactivation, and that two active copies of DSS override the function of SRY, resulting in gonadal dysgenesis because of meiotic pairing failure. It may be possible that DSS encodes a target sequence for repressing function of SRY or that DSS is involved in an X chromosome-counting mechanism. Molecular approaches have localized DSS to a 160 kb region and isolated candidate genes such as DAX-1 and MAGE-Xp, but there has been no formal evidence equating the candidate gene with DSS. In addition to its clinical importance, the exploration of DSS must provide a useful clue to phylogenetic studies of sex chromosomes and dosage compensation.

Animals↗
PubMed1996

Potentiated cAMP rise in metabotropically stimulated rat cultured astrocytes by a Ca2+-related A1/A2 adenosine receptor cooperation.

Adenosine agonists favoured an intracellular Ca2+ rise in cultured type 1 astrocytes if the metabotropic glutamate receptors were concomitantly stimulated by (2S, 1's, 2's)-2-(carboxycyclopropyl)glycine (L-CCG-I; group II agonist), quisqualate (group I agonist) or 1-aminocyclopentane-trans-1, 3-dicarboxylic acid (t-ACPD; groupI/II agonist). Since the generation of a Ca2+ signal reflected a newly adopted adenosine A1 receptor action, we tested the possible consequence that the established opposing control of the cellular cAMP content by inhibitory A1 and stimulatory A2 receptor activation was also altered. During metabotropic receptor stimulation by LCCG-I, quisqualate or t-ACPD, the non-selective adenosine agonist 2-chloroadenosine (Cl-adenosine) caused a potentiated cAMP increase which markedly exceeded that produced by Cl-adenosine alone. This cAMP potentiation resulted from altered and Ca2+-dependent A1/A2 receptor cooperation. It was abolished by A1 receptor blockade and could not be achieved in the presence of t-ACPD by the A1 agonist R(-)N6-(2-phenylisopropyl)-adenosine or by the A2 agonist 5'-N-ethyl carboxyamidoadenosine alone, but obtained using their combination. The cAMP potentiation was blocked by intracellular Ca2+ chelation and the required A1 receptor action could be mimicked by a Ca2+ signal generated by the P2y receptor agonist adenosine 5'-(beta-thio)diphosphate. The results support the conclusion that nanomolar concentrations of adenosine may influence astrocyte reactions by stimulating Ca2+ and cAMP-dependent signalling cascade.

Amino Acids, Dicarboxylic↗
PubMed1996

Early squamous cell carcinoma of the lung: CT and pathologic correlation.

PURPOSE: To study the factors that influence computed tomographic (CT) visibility of early squamous cell carcinoma, which was defined as a lesion confined to the bronchial wall without lymph node metastasis. MATERIALS AND METHODS: CT was performed in 18 patients with 18 early squamous cell carcinoma lesions. The 5.0-mm or thinner sections were reviewed independently by three observers who were aware of the bronchoscopic findings, and the visibility of the lesions was correlated with histopathologic findings. RESULTS: Tumors consisted of 13 flat and five polypoid lesions. Three of the lesions were epithelial, eight were subepithelial, and seven were cartilaginous or extracartilaginous. Eleven lesions were visualized at CT as an endobronchial mass or focal bronchial wall thickening. Lesions with polypoid growth and/or cartilaginous or extracartilaginous invasion were all visualized, even on 5-mm-thick sections. Subepithelial lesions could be demonstrated when located at bronchi with craniocaudal orientation. CONCLUSION: CT is a valuable tool for diagnosis of early squamous cell carcinomas, particularly when lesions show polypoid growth and/or invade the cartilaginous layer.

Aged↗
PubMed1996

Three-dimensional organization of lymphatics in the dog stomach: a scanning electron microscopic study of corrosion casts.

The three-dimensional organization of the lymphatics in the dog stomach was studied by scanning electron microscopy of corrosion casts, which were made by direct parenchymal injection of low-viscosity Mercox-resin into the mucosa and the muscular layers. Although the organization of lymphatics in the stomach has been studied by a variety of methods, the origin of the lymphatics and their connection in each layer has not been clearly defined. In this study, using dog stomach because of its structural similarity to the human stomach, we defined the lymphatic structure in all gastric layers, with lymphatics absent in the upper two-thirds of the lamina propria mucosae. They were first encountered at the deepest level of the lamina propria, immediately above the lamina muscularis mucosae. These lymphatics were composed of single-layered irregular meshes. Slender lymphatics arising from this network passed through the lamina muscular is mucosae and drained into the lymphatic plexus, which was composed of thicker lymphatics at the uppermost layer of the submucosa. Lymphatic valves were frequently seen in this plexus. From this plexus, slender connecting lymphatics with valves extended straight downward without lateral communications and drained into the lymphatic plexus at the deepest layer of the submucosa. This latter plexus, composed of large-caliber lymphatics, issued flattened lymphatics which formed a three-dimensional network in the muscular layer. The subserosal lymphatics were composed of thick lymphatics with tortuous courses and drained into the efferent lymphatics.

Animals↗