Biomedical subjects

K Ohtsuka

Publications and source records attributed to K Ohtsuka.

At least 55 records · Page 3Linked to original sources

PubMed1999

Presence of molecular chaperones, heat shock cognate (Hsc) 70 and heat shock proteins (Hsp) 40, in the postsynaptic structures of rat brain.

The synaptic localization of molecular chaperones, heat shock cognate protein 70 (Hsc70) and Hsp40, was investigated immunohistochemically in the normal rat brain. Postsynaptic density (PSD) fractions contained a constitutive form of HSP70, heat shock cognate protein 70 (Hsc70 or p73) but not inducible form of HSP70 (p72). The immunoreactivities of Hsc70 (p73) were distributed throughout the rat brain, in neuronal somata, dendrites and axons. Their immunoreactivity in neurons was localized in the cytoplasmic matrix, dendrites, and spines at the electron microscopic level. Presynaptic terminals, but less frequently than postsynaptic staining, were also reactive. Postsynaptic areas immediately beneath the synaptic contact or PSDs were immunoreactive for Hsc70. The Hsp40 was highly concentrated in PSD fractions. The staining of Hsp40 immunoreactivity was punctate and distributed widely in the brain. Hsp40 immunoreactivity was localized in dendritic spines, especially in the subsynaptic web, with weak staining of PSDs at the electron microscopic level. Double immunofluorescent staining and confocal microscopy revealed that Hsc70 and Hsp40 were co-localized on somata and neuronal processes of cultured cerebral neurons, on which synaptophysin immunoreactive spots were scattered. These results suggest that Hsp40 and Hsc70 are co-localized at postsynaptic sites and postsynaptic chaperone activity may be mediated by these two heat shock proteins.

Animals↗

PubMed1999

Problems in neoadjuvant chemoradiotherapy preceding surgery for advanced squamous cell carcinoma of the thoracic esophagus.

The adverse effect of neoadjuvant chemoradiotherapy on the postoperative course in esophageal cancer was studied in 9 patients undergoing neoadjuvant chemoradiotherapy preceding surgery for thoracic esophageal carcinoma possibly involving adjacent organs (neoadjuvant group), and 13 patients undergoing surgery without neoadjuvant therapy for same disease (control group). The two groups were compared for volume of intraoperative hemorrhage, surgical duration, frequency of postoperative morbidity, and for postoperative changes in blood platelet counts, and serum thrombopoietin and interleukin-6 levels. Mean intraoperative blood loss was 1121 g (580-1,662 g) in the neoadjuvant group and 546.5 g (274.7-778.3 g) in controls group (Student's T test: p < 0.01). No significant difference was seen found between the two groups in the degree of postoperative deterioration in cardiopulmonary function or in interleukin-6 levels. Blood platelet counts decreased in both groups until postoperative day 7, but recovery on postoperative day 14 was significantly depressed in the neoadjuvant group compared to controls. Serum thrombopoietin levels were higher in the neoadjuvant group than in controls (Mann-Whitney U-test: p < 0.05). We found that neoadjuvant chemoradiotherapy induces latent postoperative myelosuppression and may lead to intractable infection.

Aged↗

PubMed1999

Clinical findings in a patient with spontaneous arteriovenous fistulas of the orbit.

PURPOSE: To report clinical and radiologic findings of a patient with spontaneous arteriovenous fistulas of the orbit. METHOD: Case report. RESULTS: A 73-year-old woman was initially examined with a 1-year history of mild proptosis of the right eye. She had no history of trauma. Neuro-ophthalmologic examination disclosed dilatation of conjunctival vessels, increased intraocular pressure, mild proptosis and bruit in the right eye, and ocular signs suggestive of carotid-cavernous sinus fistulas or orbital arteriovenous malformations. The patient exhibited dilation of the superior ophthalmic vein in enhanced computed tomography of the orbit. Selective cerebral angiography disclosed communications between branches of both ophthalmic and facial arteries and the superior ophthalmic vein in the orbit. CONCLUSION: Arteriovenous fistulas of the orbit must be considered in the differential diagnosis of carotid-cavernous sinus fistulas and arteriovenous malformations, although they are quite rare.

Aged↗

PubMed1999

Topless optic disk syndrome without maternal diabetes mellitus.

PURPOSE: To describe four cases of topless optic disk syndrome without maternal diabetes mellitus. METHOD: Four patients had incidentally discovered inferior visual field defects. RESULTS: Ophthalmoscopic examinations in all four patients disclosed superiorly displaced entrances of the central retinal artery and thinning of the superior peripapillary nerve fiber layers. One patient had a superior peripapillary crescent with pallor of the superior disk. These clinical findings were consistent with a diagnosis of superior segmental optic hypoplasia, the topless disk. None of the patients had mothers who had diabetes. CONCLUSIONS: The topless optic disk syndrome can occur in the absence of maternal diabetes mellitus.

Adult↗

PubMed1999

H-magnetic resonance spectroscopy of retrobulbar tissue in Graves ophthalmopathy.

PURPOSE: Accumulation of glycosaminoglycans in the orbit may play an important role in the development of Graves ophthalmopathy. Therefore, it might be clinically useful to evaluate the concentration of glycosaminoglycans in the orbit in patients with Graves disease. We investigated the concentration of glycosaminoglycans in retrobulbar tissue using in vivo 1H-magnetic resonance spectroscopy. METHODS: A model solution of 1% chondroitin sulfate (one of the components of the glycosaminoglycans complex) was initially examined using 1H-magnetic resonance spectroscopy, and the resonance of chondroitin sulfate was identified. 1H-magnetic resonance-spectroscopy spectra of retrobulbar tissue were obtained in 16 normal volunteers (28 eyes) and 23 patients with Graves ophthalmopathy (36 eyes). The 1H-magnetic resonance spectroscopy spectrum of chondroitin sulphate in the retrobulbar in vivo tissue was identified by assignments through lineshape comparisons of spectra of the model solutions in vitro and the retrobulbar tissue in vivo. Chondroitin sulphate-peak/H2O-peak ratios were calculated. To verify the results of in vivo 1H-magnetic resonance spectroscopy, retrobulbar tissue samples from five patients, who underwent orbital decompression surgery, were tested for reactivity to chondroitin sulfate proteoglycan by enzyme-linked immunosorbent assay (ELISA). RESULTS: Multiple peaks, with a large peak at 5.24 ppm, were observed in 1H-magnetic resonance spectroscopy spectra of the model solution. A peak at 5.24 ppm was also observed in spectra of the retrobulbar tissue in all of the normal subjects and the patients. The mean value of the 5.24 ppm-peak/H2O-peak ratio was 0.1781 (SD = 0.0498, range, 0.0775 to 0.2282) in the normal subjects and 0.2874 (SD = 0.1357, range, 0.1405 to 0.7377) in the patients. The 5.24 ppm-peak/H2O-peak ratios were significantly increased in the patients with Graves ophthalmopathy (P < .01). The 5.24 ppm-peak/ H2O-peak ratio was correlated with the chondroitin sulphate concentration in retrobulbar tissue samples as evaluated by ELISA (r = .69). CONCLUSIONS: This study suggests that 1H-magnetic resonance spectroscopy of the retrobulbar tissue allows us to estimate the concentration of chondroitin sulphate proteoglycan in the retrobulbar tissue. 1H-magnetic resonance spectroscopy of the retrobulbar tissue may be a new clinical tool for the evaluation of Graves ophthalmopathy.

Adolescent↗

PubMed1999

Percutaneous transpedicular biopsy of thoracic and lumbar vertebrae--method and diagnostic validity.

BACKGROUND: Percutaneous transpedicular needle biopsy was performed on thoracic and lumbar vertebral bodies with a thin trocar (2.0 mm outer diameter) under observation with a conventional X-ray image intensifier in order to establish a correct histopathological diagnosis. We also evaluated the clinical validity of this less invasive diagnostic method in terms of the accuracy of the pathological diagnosis. METHODS: Twenty-eight thoracic or lumbar vertebrae of 26 patients with abnormalities observed on routine X-ray, CT, or MRI images underwent percutaneous transpedicular needle biopsy under local anesthesia. A threaded trocar with an outer diameter of 2.0 mm was screwed into the intra-vertebral lesion through the pedicle from the posterior side under control of X-P imaging, and a small amount of tissue or fluid was collected. RESULTS: For all patients but two, where inadequate specimens were obtained, correct diagnoses were made, which were confirmed by pathological diagnoses of massive tissue obtained during subsequent reconstructive surgery. CONCLUSIONS: The accuracy rate of diagnosis with this biopsy method was 92% without significant intra- or postoperative complications. Therefore, it can be concluded that this less invasive biopsy method used in conjunction with conventional X-ray apparatus has good potential to result in correct preoperative diagnosis of thoracic and lumbar lesions so that more effective treatment can be determined.

Adult↗

PubMed1999

Role of NK cells and TGF-beta in the regulation of T-cell-dependent antibody production in health and autoimmune disease.

Natural killer (NK) cells are a third lymphocyte population especially important in innate immunity. NK cells may also have an important role in the regulation of acquired immunity. These lymphocytes spontaneously produce large amounts of both active and latent transforming growth factor-beta (TGF-beta). NK-cell-derived TGF-beta1 enabled activated CD8(+) T cells to inhibit antibody production by blocking the induction of this response. Production of lymphocyte-derived TGF-beta is decreased in systemic lupus erythematosus. Insufficient levels of this cytokine in SLE and other autoimmune diseases may contribute to defective T regulatory cell function characteristic of this and other autoimmune diseases. NK cells are found in mucosal tissues and the TGF-beta spontaneously released by these cells could contribute to the usual tolerogenic response of T cells to antigens presented at these sites. Thus, in addition to its well known immunosuppressive effects, TGF-beta could have an equally important role in the generation of regulatory T cells.

Animals↗

PubMed1999

Biodiesel fuel production from plant oil catalyzed by Rhizopus oryzae lipase in a water-containing system without an organic solvent.

A new enzymatic method of synthesizing methyl esters from plant oil and methanol in a solvent-free reaction system was developed. It is anticipated that such plant oil methyl esters can be used as a biodiesel fuel in the future. Lipase from Rhizopus oryzae efficiently catalyzed the methanolysis of soybean oil in the presence of 4-30 wt% water in the starting materials; however the lipase was nearly inactive in the absence of water. The methyl ester (ME) content in the reaction mixture reached 80-90 wt% by stepwise additions of methanol to the reaction mixture. The kinetics of the reaction appears to be in accordance with the successive reaction mechanism. That is, the oil is first hydrolyzed to free fatty acids and partial glycerides, and the fatty acids produced are then esterified with methanol. Although R. oryzae lipase is considered to exhibit 1(3)-regiospecificity, a certain amount of 1,3-diglyceride was obtained during the methanolysis and hydrolysis of soybean oil by R. oryzae lipase solution. Therefore, the high ME content in the reaction mixture is probably attributable to the acyl migration from the sn-2 position to the sn-1 or sn-3 position in partial glycerides.

Journal Article↗

PubMed1999

Regulation of brain renin-angiotensin system by benzamil-blockable sodium channels.

Changes in the renin-angiotensin system (RAS) mRNAs in the brain and the kidney of rats after administration of DOCA and/or sodium chloride were assessed by use of a competitive PCR method. Benzamil, a blocker of amiloride-sensitive sodium channels, was infused intracerebroventricularly or intravenously for 7 days in DOCA-salt or renal hypertensive rats, and the effects of benzamil on the brain RAS mRNAs were determined. Renin and ANG I-converting enzyme (ACE) mRNAs were not downregulated in the brain of rats administered DOCA and/or salt; however, these mRNAs were decreased in the kidney. Intracerebroventricular infusion of benzamil decreased renin, ACE, and ANG II type 1 receptor mRNAs in the brain of DOCA-salt hypertensive rats but not in the brain of renal hypertensive rats. The gene expression of the brain RAS, particularly renin and ACE, is regulated differently between the brain and the kidney in DOCA-salt hypertensive rats, and benzamil-blockable brain sodium channels may participate in the regulation of the brain RAS mRNAs.

Amiloride↗

PubMed1999

Multilocular cystic adenomyoma of the pelvic cavity: A rare clinical and histological entity in a young man.

We report a large complex cystic pelvic mass encountered in a 16-year-old man complaining of perineal discomfort. A large and elastic hard mass was palpated on the right anterior wall of the rectum with no discernible prostate on digital rectal examination. Prostatic tumor markers were elevated. Excretory urography and urethrocystography showed a filling defect with a smooth edge on the right side of the bladder. Magnetic resonance imaging demonstrated a mass with a mosaic pattern between the right side of the bladder and the rectum. We performed ultrasound-guided transrectal needle core biopsy of the mass. The pathologist suspected hyperplastic glandular epithelium of prostatic origin with focal inflammatory cell infiltration, but there was no sign of malignancy. We thought that the tumor arose from the prostate. Surgery was successfully performed. The tumor was located on the right side of the pelvic cavity and adhered to the right lobe of the seminal vesicle. En bloc excision was performed. This lesion histologically proved to be a multilocular prostatic tissue with a seminal vesicle component, without communication to the surrounding tissue. Such a lesion has not previously been reported in the literature.

Adenomyoma↗

PubMed1999

The relationship between defects in lymphocyte production of transforming growth factor-beta1 in systemic lupus erythematosus and disease activity or severity.

Transforming growth factor beta (TGF-beta) comprises of a family of proteins with pleiotropic signaling properties and potent immunoregulatory effects. In SLE we recently reported that lymphocyte production of the total and active forms of TGF-beta1 was decreased. Here we asked whether these defects correlate with disease activity and/or severity. TGF-beta1 production by blood lymphocytes from 17 prospectively studied SLE patients was compared with 10 rheumatoid arthritis (RA) patients and 23 matched healthy controls. The RA levels of active TGF-beta1 were lower than controls, but were not deceased to the extent found in SLE. Levels of constitutive and anti-CD2 stimulated active TGF-beta1 detected in picomolar amounts were markedly reduced in six untreated patients hospitalized with recent onset, very active and severe SLE and similarly reduced in 11 patients with treated, less active disease. By contrast, decreased production of total TGF-beta1 inversely correlated with disease activity. These studies suggest, therefore, that although impaired lymphocyte secretion of the latent precursor of TGF-beta1 may result as a consequence of disease activity, a decreased capacity to convert the precursor molecule to its active form may pre-date disease onset. Insufficient exposure of T cells to picomolar concentrations of TGF-beta1 at the time they are activated can result in impaired down-regulation of Ig synthesis. Therefore, decreased lymphocyte production of active TGF-beta1 in SLE could be an immunologic defect which contributes to the B cell hyperactivity characteristic of this disease.

Adult↗

PubMed1999

Cytokine-mediated down-regulation of B cell activity in SLE: effects of interleukin-2 and transforming growth factor-beta.

We have recently reported that transforming growth factor-beta (TGF-beta) co-stimulates interleukin-2 (IL-2) activated CD8+ T cells to down-regulate antibody production. In SLE, lymphocyte production of both IL-2 and TGF-beta is decreased. Here we report that a brief treatment of PBMC from SLE patients with IL-2 and TGF-beta can result in marked inhibition of spontaneous polyclonal IgG and autoantibody production. Peripheral blood mononuclear cells (PBMC) from 12 patients with active SLE were exposed to IL-2 with or without TGF-beta for three days, washed and cultured for seven more days. The mean decrease in IgG secretion was 79%. The strongest inhibitory effect was observed in cases with the most marked B cell hyperactivity. Spontaneous production of anti-nucleoprotein (NP) antibodies was observed in four cases and cytokine treatment of PBMC decreased autoantibody production by 50-96%. IL-2 inhibited Ig production by either TGF-beta-dependent or independent mechanisms in individual patients. In a study of anti-CD2 stimulated IgG production in a patient with active SLE, we documented that IL-2 and TGF-beta reversed the enhancing effects of CD8+ T cells on IgG production and induced suppressive activity instead. These results raise the possibility that cytokine-mediated down-regulation of B cell hyperactivity in SLE may have therapeutic potential.

Adolescent↗

PubMed1999

Serum hepatocyte growth factor as a possible indicator of vascular lesions.

To investigate the role of human hepatocyte growth factor (hHGF) in vascular lesions associated with endothelial injury, we measured serum hHGF concentrations in subjects with retinal arteriosclerosis, coronary atherosclerosis, or arteriolitis due to Henoch-Schönlein purpura. Individuals with more advanced grades of retinal arteriosclerosis showed higher serum hHGF concentrations [grade 0, 0.053+/-0.005 ng/mL (n = 68); grade 1, 0.144+/-0.022 ng/mL (n = 21; P<0.01 vs. grade 0); grade 2, 0.338+/-0.036 ng/mL (n = 20; P<0.01 vs. grade 0 or 1); grade 3, 0.526+/-0.051 ng/mL (n = 9; P<0.01 vs. grade 0, 1, or 2)]. Patients with active arteriolitis due to Henoch-Schönlein purpura showed higher (P<0.01) serum hHGF concentrations (0.347+/-0.038 ng/mL; n = 14) than those in the remission phase (0.097+/-0.017 ng/mL; n = 19). Mean serum hHGF concentrations were higher in subjects with coronary atherosclerosis than in those without, but a significant overlap in serum hHGF concentrations was found between subjects with and those without coronary atherosclerosis. Serum hHGF may be an indicator of the presence or development of arteriolar lesions.

Aged↗

PubMed1999

An electromyogram study on mandibular movement in unilateral cleft lip and palate patients before and after orthodontic treatment.

The purpose of this study is to investigate masticatory muscle function in subjects with unilateral cleft lip and palate compared with normal occlusion and the extents of improvement before and after orthodontic treatment. Subjects were twenty pretreatment patients, thirty posttreatment patients and ten controls. Electromyograms were recorded from their masticatory muscles during masticatory movement and tapping movement. Reduction of duration/stroke ratio (D/S) was observed in electromyograms obtained during masticatory movement after orthodontic treatment. The reduction was especially notable in the masseter muscle. In spite of a significant reduction in coefficient of variation (CV) values, a significant difference between the posttreatment group and the control group indicated some persisting irregularity in masticatory movement. Electromyograms taken during tapping movement showed no change in latency in the posttreatment group, but duration of the silent period (SP) was shortened and SP appearance increased. The findings outlined above reveal electromyographically clear improvements in masticatory muscle functions and jaw reflex mechanisms after orthodontic treatment. Nevertheless, parameters for subjects with cleft lip and palate still differed from those for controls with normal occlusion. The influence of plastic surgery in subjects with the defects discussed here causes maxillary retrusion, which in turn results in skeletal malocclusion. Orthodontic treatment should be designed to compensate this dentally and alveolarly. This design and the need to improve masticatory functions would contribute to eliminate the extreme difficulty of the therapeutic process.

Adolescent↗

PubMed1999

Treatment of cervical compressive myelopathy with a new dorsolateral decompressive procedure.

OBJECT: A new dorsolateral decompressive procedure involving a unilateral approach has been devised for the treatment of cervical compressive myelopathy. In this operation, the posterior spinal elements of the contralateral side are not disturbed, and thus, postoperative deformity of the cervical spine can be avoided. Following decompressive surgery via the unilateral approach, the cervical spine was kept more stable compared with the results obtained after wide laminectomy or other expansive laminoplasty procedures. METHODS: Twenty-six patients underwent dorsolateral decompressive surgery, and the patients' clinical and radiological results were examined during the follow-up period to evaluate neurological function and postoperative deformities of the cervical spine. The underlying conditions for myelopathy were cervical spondylosis (19 patients), ossification of posterior longitudinal ligament (three patients), and ossification of yellow ligament (four patients). The follow-up period ranged from 6 to 110 months (average 35.5 months). Functional recovery, which was rated by using the Japanese Orthopaedic Association scoring system, was an average of 56% in all patients (100% being equal to full recovery). The recovery rate was compatible with those attained after other expansive laminoplasty procedures. Radiographically, progression to swan-neck or kyphotic deformity was not observed in any patient. No postoperative spinal instability was noted. Based on computerized tomography myelograph evaluation, the average transectional area of the dural tube at the C4-5 level was expanded from 122 mm2 to 169 mm2, and the transectional area of the spinal cord at the C4-5 level was expanded from 39.6 mm2 to 52.9 mm2 after surgery. CONCLUSIONS: The authors conclude that this operative procedure could be used as a new option for the treatment of cervical compressive myelopathy.

Adult↗

PubMed1999

Anterior surgery with short fusion using the Zielke procedure for thoracic scoliosis: focus on the correction of compensatory curves.

Anterior instrumentation is recommended to correct idiopathic thoracolumbar or lumbar scoliosis through short fusion within the major curve. Only a few reports exist of anterior surgical correction for thoracic scoliosis. This study assessed the results of Zielke instrumentation for thoracic curve and analyzed the three-dimensional correction of deformity, especially correction of the uninstrumented compensatory curve. Seventeen patients, who had undergone selective thoracic correction and fusion using the Zielke procedure to treat thoracic scoliosis, had been followed for at least 3 years. Three-dimensional correction was evaluated radiographically. Furthermore, three-dimensional back deformities were evaluated using a topographic body scanner. Twelve patients with a single thoracic curve and five with a double curve were all female, with a mean age of 14.6 years. The preoperative main thoracic curve was 54.8 degrees +/- 10.5 degrees (range, 40-78 degrees), and it was 23.8 degrees +/- 10.5 degrees (range, 7-40 degrees) at the final follow-up examination (p < 0.0001). The average correction rate of the main curves was 56.6%. By correcting the thoracic curve, the upper and lower compensatory curves were corrected spontaneously without surgical instrumentation, with average correction rates of 45.1% and 50.2%, respectively. The average correction loss of the main curve was 2.3 degrees. The hump angle measured using a topographic body scanner decreased from 12.8 degrees +/- 4.5 degrees to 8.4 degrees +/- 4.3 degrees after surgery (p = 0.0001). Of the three patients in whom the rod broke up, only one showed a correction loss of 10 degrees; however, bony fusion was obtained. Anterior short fusion for thoracic scoliosis appears to offer significant correction, stabilization, and spontaneous correction of the compensatory lumbar curve without limiting lumbar motion.

Adolescent↗

PubMed1998

Characterization of HSE sequences in human Hsp40 gene: structural and promoter analysis.

We have recently cloned a gene of Hsp40, a human homologue of bacterial DnaJ. Here we describe the structural and promoter analysis of human Hsp40 gene. Analysis of Hsp40 transcripts by 5' and 3' RACE suggested that they have different 3' ends, and primer extension studies revealed that the major transcription initiation site was localized 47 bp upstream of the ATG translation initiation codon. Promoter analysis using deletion derivatives defined a minimal region which was active in response to heat shock. The region contained the consensus heat shock element (HSE) sequences. The factor bound to these sequences was suggested to be a heat shock factor 1 (HSF1) by gel mobility supershift assay. In vivo footprinting and promoter analysis revealed that the HSEs in 5' upstream region of human Hsp40 gene were composed of eight contiguous (A/G)GAAN motifs and were essential for heat shock response. These results indicate that Hsp40 is a real heat shock protein. It is also shown that the HSE found in the first intron might not be the essential element for heat shock response.

Base Sequence↗

PubMed1998

Generation of an inhibitory circuit involving CD8+ T cells, IL-2, and NK cell-derived TGF-beta: contrasting effects of anti-CD2 and anti-CD3.

Although the phenomenon of immunosuppression is well established, the mechanisms involved in the generation of lymphocytes with down-regulatory activity are poorly understood. Unlike anti-CD3 antibodies, mitogenic combinations of anti-CD2 antibodies do not stimulate human PBL to produce IgM or IgG. In determining the reason for this difference, we have found that anti-CD2 triggers an inhibitory circuit facilitated by TGF-beta provided by NK cells. Stimulation of PBL with anti-CD2, but not anti-CD3, generated substantial amounts of active TGF-beta. NK cells were found to be a significant source of TGF-beta and were the only lymphocyte population that constitutively produced this cytokine. Anti-CD2 enhanced the production of active TGF-beta by purified NK cells. TGF-beta. After the removal of NK cells or the addition of anti-TGF-beta, anti-CD2 could stimulate Ig production. Anti-TGF-beta had to be added within the first 24 h for a maximal effect. Moreover, a short, overnight exposure of CD8+ T cells to TGF-beta could prime them for suppressor activity provided that IL-2 was also present. Thus, the presence of active TGF-beta coincident with CD8+ T cell activation can condition these cells to mediate down-regulatory activity, and NK cells can serve as the source of this cytokine.

Adult↗