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Biomedical subjects

K Ohtsuka

Publications and source records attributed to K Ohtsuka.

At least 163 records · Page 9Linked to original sources
PubMed1994

[Anatomical study of the tonsillar bed: the topographical relationship between the palatine tonsil and the lingual branch of the glossopharyngeal nerve].

The topographical relationship between the lingual branch of the glossopharyngeal nerve (LBGN) and the muscle layer of the palatine tonsillar bed was investigated by gross and histological observation in 107 sides of 83 Japanese adult cadavers, aged 27-88yr, in order to provide anatomical data facilitating the prevention of taste disturbance caused by injury to the LBGN during tonsillectomy. The muscular composition and lamination of the tonsillar bed are thought to be unchanged by aging or pathological conditions such as inflammation, in contrast to the morphological instability of the palatine tonsil itself. In the present study, the nerve branch was often (23.4%) observed to pass along the inferior side of the styloglossus muscle and to be located lateral to the superior constrictor pharyngeal muscle, during almost its entire course to the base of the tongue, so that the palatine tonsil was clearly separated from the LBGN. In 55.1% of cases, however, the muscle lining observed at the tonsillar bed was not continuous, and instead thin muscle bundles, derived from the stylopharyngeus, palatopharyngeus or superior constrictor pharyngeal muscles, partly covered the tonsillar capsule externally. Moreover, in 21.5% of cases, the LBGN was firmly adherent to the tonsillar capsule, due to complete absence of the lining muscles at the tonsillar bed. In these cases, and also probably in a similar percentage of patients undergoing tonsillectomy, taste disturbance could occur upon removal of the hypertrophic tonsillar capsule produced by chronic inflammation. Therefore, tonsillectomy with minimal disturbance of the tonsillar bad is recommended in all cases.

Adult↗
PubMed1994

Embryological study of the spinal ligaments in human fetuses.

We studied embryological development of the human spinal ligaments by dissecting 25 fetuses that ranged from 6 to 24 weeks of gestational age. At 6 and 7 weeks, the spine consisted of light zones and dark zones. The light zones were hypocellular and corresponded to vertebral bodies. The dark zones were hypercellular and corresponded to intervertebral disks. The anterior longitudinal ligament was identified at the gestational age of 8 weeks. At 10 weeks, the posterior longitudinal ligament was detected. At 12 weeks, laminae, the ligamentum flavum, and an ossification center were identified. At 15 weeks, fibers of the ligamentum flavum became clearer, but they were not as well as stained as the adult ligamentum flavum. The enthesis of the ligaments in the human fetuses was not completely identical to that in adults.

Embryonic and Fetal Development↗
PubMed1994

Properties of memory-guided saccades toward targets flashed during smooth pursuit in human subjects.

PURPOSE: This study in human subjects investigated whether or not the saccade system can monitor smooth changes of the eye position in total darkness. METHODS: The authors studied the properties of memory-guided saccades toward targets flashed during pursuit eye movements (target velocities of 15 degrees/s, 30 degrees/s, and 45 degrees/s) in four normal human subjects. Subjects were instructed to execute memory-guided saccades toward the position of the flashed target in total darkness when the pursuit target was extinguished. RESULTS: The vector of the saccade was more highly correlated with the vector of "spatial error" (the vector from the position of the eye at the time of the saccade to the position of the flashed target in space) than with the vector of "retinal error" (the vector from the position of the eye at the time of the presentation of the flashed target to the position of the flashed target). The amplitude and direction errors of memory-guided saccades were correlated with the amplitude of the retinal error but not with amplitude of eye deviation after the presentation of the flashed target. Pursuit velocity did not affect the error of the saccade. CONCLUSIONS: These findings suggest that the saccade system can monitor smooth changes of the eye position in total darkness, regardless of the velocity of pursuit, and that the accuracy of memory-guided saccades is dependent only on the amplitude of the retinal error.

Adult↗
PubMed1993

Cloning of a cDNA for heat-shock protein hsp40, a human homologue of bacterial DnaJ.

We here isolated and characterized a cDNA clone encoding 40-kDa heat-shock protein hsp40 from cDNA expression library of human placenta by immunoscreening with anti-hsp40 antibody. N-terminal amino acid sequence (48 residues) deduced from the base sequence was completely identical to that of hsp40 purified from HeLa cells. Deduced amino acid sequence of the cDNA is homologous to bacterial DnaJ heat-shock protein and its homologues in yeast such as SCJ1, YDJ1(MAS5), SIS1, SEC63 and Zuotin. Nucleotide sequence identity between hsp40 and HDJ1 (another human DnaJ homologue) is more than 98%, suggesting that these two proteins are the same gene product.

Amino Acid Sequence↗
PubMed1993

Characterization of intermediate TCR cells in the liver of mice with respect to their unique IL-2R expression.

We previously demonstrated that T cells with intermediate TCR intensity (i.e., intermediate TCR cells) which possibly generate extrathymically are preferentially present in the liver of mice. This population was further characterized with respect to the expression of IL-2 receptor (IL-2R) and others. Two-color staining for CD3 (or TCR alpha beta) and IL-2R alpha (and beta) demonstrated that intermediate TCR cells as well as NK cells constitutively expressed IL-2R beta but not IL-2R alpha. A small number of intermediate TCR cells was also identified in other immune organs by using this staining method. In vivo and in vitro stimulation experiments revealed that regular, bright TCR cells, which originally lacked the expression of both IL-2R alpha and beta, acquired the highest expression of IL-2R alpha and beta, while intermediate TCR cells did not. These results suggested, in conjunction with their other properties demonstrated here, that intermediate TCR cells might be more primitive T cells than regular T cells of thymic origin.

Animals↗
PubMed1993

Effect of ATP on the release of hsp 70 and hsp 40 from the nucleus in heat-shocked HeLa cells.

We have recently found a novel 40-kDa heat-shock protein (hsp 40) in mammalian and avian cells and reported that the N-terminal amino acid sequence of mammalian hsp 40 has homology with the bacterial DnaJ heat-shock protein. Also, hsp 40 has been shown to be translocated from the cytoplasm into the nuclei/nucleoli by heat shock and colocalized with hsc 70 (p73) in the nucleoli of exactly the same cells. We here investigated the effect of ATP on the release of hsp 70 (both constitutive p73 and inducible p72) and hsp 40 from the nuclei/nucleoli of heat-shocked HeLa cells which were permeabilized with Nonidet-P40 using immunofluorescence and immunoblotting. Hsp 70 in the nucleoli was released by the addition of ATP but not by ADP, GTP, nonhydrolyzable ATP, nor high salt buffer. In contrast, hsp 40 was not released from the nucleoli with any of these treatments or any combination of these treatments. Thus, hsp 40 might dissociate spontaneously from the nucleoli after hsp 70 has been released in an ATP-dependent manner. Using cell fractionation methods, we showed that while the majority of hsp 40 is localized in the cytoplasm, a small portion of it is located in the microsome fraction in non-heat-shocked control cells and in cells which recovered from heat shock.

Adenosine Triphosphate↗
PubMed1993

Afferent and efferent connections of the cortical accommodation area in the cat.

Accommodative responses were evoked by microstimulation of a circumscribed area in the lateral suprasylvian (LS) cortex of the cat. We studied anatomical connections of this area with WGA-HRP. We identified an accommodation-related area by systematic microstimulation of the LS cortex in each of nine cats. Accommodative and pupillary responses were monitored by an infrared optometer and a pupillometer, respectively. WGA-HRP was injected into the accommodation-related area where accommodative responses were elicited with low-intensity microstimulation, but pupillary responses were not evoked. Retrogradely labeled cells were found mainly in ipsilateral areas 17, 18 and 19, the pulvinar, the lateral posterior nucleus of the thalamus (LP) and the contralateral LS area. Fewer labeled cells were found in ipsilateral areas 20 and 21, the ventral lateral suprasylvian area (VLS), the splenial visual area (SVA) and the lateral geniculate nucleus (LGN). Anterogradely labeled terminals were located mainly in the ipsilateral LP, the rostral portion of the pontine nuclei and the superficial layers of the ipsilateral superior colliculus which corresponds to the representation of the central visual field. Less dense labeled terminals were also found in the ipsilateral nucleus of the optic tract (NOT) in two cats.

Accommodation, Ocular↗
PubMed1993

Radioresistance of intermediate TCR cells and their localization in the body of mice revealed by irradiation.

Extrathymic generation of T cells in the liver and in the intestine was recently demonstrated. We investigated herein whether such T cells, especially those in the liver, are present in other organs of mice. This investigation is possible employing our recently introduced method with which even a minor proportion of extrathymic, intermediate TCR cells in organs other than the liver can be identified. Intermediate TCR cells expressed higher levels of IL-2R beta and LFA-1 than bright TCR cells (i.e., T cells of thymic origin) as revealed by two-color staining. Although intermediate TCR cells were present at a small proportion in the spleen and thymus, they predominated in these organs after irradiation (9 Gy) and bone marrow reconstitution, or after low dose irradiation (6 Gy). This was due to that intermediate TCR cells were relatively radioresistant, whereas bright TCR cells were radiosensitive. Microscopic observation and immunochemical staining showed that intermediate TCR cells in the spleen localized in the red pulp and those in the thymus localized in the medulla. These intermediate TCR cells displayed a large light scatter, similar to such cells in the liver. The present results suggest that intermediate TCR cells may proliferate at multiple sites in the body.

Animals↗
PubMed1993

Convergence paralysis after lesions of the cerebellar peduncles.

We studied vergence eye movements in a patient with limited hemorrhage affecting the right cerebellar peduncles and the hemisphere. The patient showed exotropia of 30 prism dptr during near vision. Some vergence paradigms were investigated in this patient. We studied fusional vergence evoked by placing a wedge prism before one eye. Accommodative vergence was studied by blur stimulus using a servocontrolled optometer. Lens accommodation was also recorded during blur stimulus. Although accommodative responses were normal, accommodative vergence was almost absent as well as fusional convergence in this patient. It has previously been reported that the cerebellum has a role in the control of vergence in the monkey. Our data suggest that the human cerebellum also relates to the control of vergence.

Accommodation, Ocular↗
PubMed1993

A stress-inducible 40 kDa protein (hsp40): purification by modified two-dimensional gel electrophoresis and co-localization with hsc70(p73) in heat-shocked HeLa cells.

We have previously reported that a novel 40 kDa protein is induced by heat shock and several environmental stresses in mammalian and avian cells and that the N-terminal amino acid sequence of this 40 kDa protein has homology with the bacterial DnaJ heat-shock protein. We have purified this protein (40 kDa heat-shock protein, hsp40) from HeLa cells by modified two-dimensional gel electrophoresis and generated a polyclonal antibody against hsp40. This antibody was highly specific for human hsp40 and cross-reacted weakly with rat and Chinese hamster hsp40. Indirect immunofluorescence revealed that the hsp40 in HeLa cells accumulates in the nucleus, especially in the nucleolus, during heat shock and returns to the cytoplasm during the recovery period. The kinetics of the accumulation in the nucleoli and subsequent return to the cytoplasm of hsp40 was similar to that of hsp70. In addition, hsp40 was co-localized with hsc70(p73) in heat-shocked HeLa cells as demonstrated by double immunofluorescence staining. These results suggest that hsp40 (a DnaJ homologue) and hsp70 (a DnaK homologue) may act in concert to repair (refold) denatured proteins and protein aggregates in the nuclei and nucleoli of heat-shocked HeLa cells.

Cell Nucleolus↗
PubMed1993

Endoscopic removal of foreign bodies in the mentally and physically handicapped.

Although foreign bodies of the gastrointestinal tract are common in children, they are rare in the adult. Complications of the foreign bodies are well recognized to be a cause of obstruction, bleeding and perforation of the intestine, or furthermore, they sometimes lead to death unfortunately. On the other hand, it is very difficult to diagnose and treat foreign bodies in the handicapped because of disability of complaining the symptoms. This paper reports a 31-year-old severe handicapped man suffering from foreign bodies in the esophagus and the small intestine, and was successful removed by endoscope.

Adult↗
PubMed1993

Detailed characterization of gamma delta T cells within the organs in mice: classification into three groups.

gamma delta T cells are known to localize preferentially in the epithelial regions and the hepatic sinusoids, and exhibit highly restricted V gene usage depending on their location. In the present study, gamma delta T cells in mice were further characterized in terms of their expression of the interleukin-2 receptor beta-chain (IL-2R beta), CD4 and CD8, and CD8 alpha and beta. This experiment was arranged to investigate whether gamma delta T cells have different properties depending on the organs and how gamma delta T cells are different from extrathymic alpha beta T cells, i.e. alpha beta T cells in the liver and intraepithelial lymphocytes in the intestine, in terms of the above phenotypes. Three-colour immunofluorescence tests using monoclonal antibodies revealed that gamma delta T cells can be classified into three groups: gamma delta T cells of the liver type are all IL-2R beta+, are comprised of double-negative (DN) CD8-CD4- and single-positive CD8+ (no CD4+) cells, and express CD8 alpha+ beta-; gamma delta T cells of the thymus type are a mixture of IL-2R beta+ and IL-2R beta-, are mainly DN, and express CD8 alpha+ beta+ if they carry CD8 antigens; and gamma delta T cells of the intestine type are also IL-2R beta+ or IL-2R beta-, are all CD8+, and express CD8 alpha+ beta-. gamma delta T cells in the spleen of normal mice are of the thymus type, while gamma delta T cells in the spleen of athymic nude mice seem to be of the liver type. All these properties of gamma delta T cells resemble those of extrathymic alpha beta T cells rather than regular alpha beta T cells of thymic origin. The present results reveal that gamma delta T cells and other extrathymic alpha beta T cells have many properties in common as primitive lymphocytes in phylogenetic development.

Animals↗
PubMed1993

[Concentration of mitomycin C in portal blood and peripheral blood after intra venous, intraperitoneal or intrapelvic administration].

Immediately before closing the abdomen in a curative operation for colorectal cancer, 20 mg of Mitomycin C (MMC) was administered by intravenous, intraperitoneal or intrapelvic routes, and portal blood and peripheral blood were simultaneously collected to investigate the disposition of MMC. After intravenous administration, the MMC concentration in portal and peripheral bloods changed at the same levels, showing a biphasic pattern. The maximum concentration (Cmax) seen shortly after administration was about 2 micrograms/ml. The blood halflife in phase alpha was about 5 min, and that in phase beta about 30 min. After intraperitoneal administration, the MMC concentration in portal blood was over 60 min higher than that in peripheral blood. Cmax in portal blood, seen within 5 min after administration, was about 0.5 micrograms/ml, and that in peripheral blood was about 0.2 micrograms/ml around 10 min. The half-life was about 30 min in both types of blood. After intrapelvic administration, the MMC concentration in portal blood changed at higher levels than in peripheral blood, as after intraperitoneal administration. The Cmax in portal blood, obtained within about 5 min, was about 0.3 micrograms/ml, and that in peripheral blood was about 0.1 micrograms/ml at 12 min. The half-life was about 30 min in both types of blood. As described above, the disposition of MMC was investigated on the basis of the concentration in portal and peripheral blood. As a result, intravenous MMC showed a similar change, whereas intraperitoneal or intrapelvic MMC was higher in portal blood than in peripheral blood, indicating that the disposition of MMC was different with the route of administration.

Colorectal Neoplasms↗
PubMed1992

Details of an isolation method for hepatic lymphocytes in mice.

The liver comprises a unique lymphocyte population, i.e., extrathymic alpha beta T cells with TcR of intermediate intensity. In the present study, we attempted to determine what pretreatments were appropriate to isolate hepatic mononuclear cells (MNC) containing such intermediate alpha beta TcR cells in mice. Hepatic MNC were isolated from untreated mice and mice subjected to either bleeding or liver perfusion, and the intermediate alpha beta TcR cells in each preparation were identified. For reasons of simplicity, cell purity and cell yields, hepatic lymphocytes should be obtained from mice subjected to total bleeding. Additional information on extrathymic alpha beta T cells obtained by using the recommended method is also presented.

Animals↗
PubMed1992

The relationship between hsp 70 localization and heat resistance.

Using indirect immunofluorescence we have investigated the kinetics of nuclear accumulation and removal of hsp 70 in HA-1 Chinese hamster fibroblasts exposed to elevated temperatures. The kinetics of accumulation of hsp 70 in the nuclei were found to be time/temperature dependent at all temperatures tested (42-45 degrees C). At a given temperature, the fraction of cells manifesting nuclear localization of hsp 70 increased with exposure time. For a given duration of heating, the fraction of cells manifesting nuclear localization of hsp 70 increased with the temperature. The kinetics of the nuclear accumulation of hsp 70 were similar for normal HA-1 cells, their heat-resistant variants, and transiently thermotolerant cells (triggered by prior exposure to a brief heat shock or to sodium arsenite). Upon return to 37 degrees C after heat shock, the kinetics of removal of the hsp 70 associated with the nucleus was dependent on the severity of the initial heat challenge. However, for a given heat dose, the decay of nuclear localization of hsp 70 was more rapid in thermotolerant and heat-resistant cells than in their normal counterparts. These results suggest that the increased levels of hsp 70 associated with the transient or permanently heat-resistant state may play a direct role in restoring and/or repairing heat-induced nuclear and nucleolar alterations associated with heat-induced cell killing. Furthermore, they also suggest that the heat-resistant state may involve ameliorated repair of heat-induced cellular alterations.

Animals↗