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Biomedical subjects

K Sakurai

Publications and source records attributed to K Sakurai.

At least 127 records · Page 7Linked to original sources
PubMed1997

Effects of primer-concentration on uronosyl-epimerization and sulfation patterns in p-hydroxyphenyl-O-beta-D-xylopyranoside-primed galactosaminoglycans produced by skin fibroblasts.

By supplying skin fibroblasts with different concentrations of the galactosaminoglycan chain-primer p-hydroxyphenyl-O-beta-D-xylopyranoside we have produced and recovered glycan-chains that were subsequently radio-iodinated in the hydroxyphenyl group and subjected to sequence analysis by using graded enzymic treatment followed by a combination of gel chromatography and electrophoresis. Fragments extending from the tagged reducing end to the cleavage-point were identified and quantified. Degradation by chondroitin B lyase of chains primed at 0.1 or 0.5 mM xyloside gave profiles indicating a periodic and wave-like distribution of iduronate-containing repeats, with high incidence around positions 2, 5 and onwards, whereas in chains produced at 1.0 mM xyloside the incidence of iduronate was similar in positions 1-4 and then declined. Degradation by chondroitin AC lyase indicated a high incidence of glucuronate in or near the linkage-region. There was a relatively uniform degree of sulfation in chains primed at low xyloside concentration, whereas chains primed at 1.0 mM xyloside gave very heterogeneous charge-patterns in all segments of the chain, including the linkage-region, giving the impression that adequate sulfation, probably at C-4 and at the first opportunity, is necessary to obtain an ordered and periodic epimerization pattern.

Carbohydrate Sequence↗
PubMed1997

A multiparametric analysis of occlusal and periodontal jaw reflex characteristics in young adults with normal occlusion.

Periodontal jaw reflex, duration of percussion sounds, tooth mobility, and time-moment analysis of occlusal contacts by the T-scan system was recorded in nine periodontally healthy volunteers. The results showed that (i) reflex responses to the pressure applied to the uppercentageral incisors in the lingolabial direction varied, depending on the background jaw-clenching force (BCF) of the same-sided first molars. The BCF levels to elicit excitatory reflexes were 6-8 Kgf, and inhibitory reflexes were clearly elicited with a BCF of 10 Kgf and beyond. (ii) Duration of percussion sounds via an occlusal sound analyser (4.73-4.84 mS: upper first molars, 4.89-5.00 mS: uppercentageral incisors) and tooth mobility using a 'Periotest' (3.3-3.5: upper first molars, 5.5-5.6: uppercentageral incisors) showed a normal value. (iii) The time moments of occlusal contacts were symmetrical toward the midsagittal axis of the occlusal plane. The centre of the anteroposterior occlusal contacts was located in the first molar regions.

Adult↗
PubMed1997

Craniocaudal motion velocity in the cervical spinal cord in degenerative disease as shown by MR imaging.

PURPOSE: To investigate, by means of MR phase imaging, the effects of compression on the velocity of craniocaudal motion in the spinal cord. MATERIAL AND METHODS: Spin-echo pulse sequences with velocity encoding gradients were used to examine 12 patients with cervical spondylosis and 6 normal volunteers. Oblique-axial phase images at 3 levels (cranial, middle and caudal), were obtained with prospective electrocardiogram gating. The middle level was set at the site where the spinal cord was most severely compressed, and the cranial and caudal sections were set where it was not compressed. Time-velocity curves were generated at these 3 levels and focal velocity change was correlated with motor function in the lower extremities. RESULTS AND CONCLUSION: The cord showed a higher motion velocity at the compression level than at noncompression levels. This paradoxical increase in velocity was observed in 7 out of 8 patients whose lower extremity motor function was impaired. Four patients with normal lower extremity motor function did not demonstrate this increase in velocity. An increase in motion velocity was therefore found to correlate with impaired lower extremity motor function.

Adult↗
PubMed1997

Sarin poisoning on Tokyo subway.

On the day of the disaster, 641 victims were seen at St. Luke's International Hospital. Among those, five victims arrived with cardiopulmonary or respiratory arrest with marked miosis and extremely low serum cholinesterase values; two died and three recovered completely. In addition to these five critical patients, 106 patients, including four pregnant women, were hospitalized with symptoms of mild to moderate exposure. Other victims had only mild symptoms and were released after 6 hours of observation. Major signs and symptoms in victims were miosis, headache, dyspnea, nausea, ocular pain, blurred vision, vomiting, coughing, muscle weakness, and agitation. Almost all patients showed miosis and related symptoms such as headache, blurred vision, or visual darkness. Although these physical signs and symptoms disappeared within a few weeks, psychologic problems associated with posttraumatic stress disorder persisted longer. Also, secondary contamination of the house staff occurred, with some sort of physical abnormality in more than 20%.

Adolescent↗
PubMed1997

Contribution of cell proliferative activity to malignancy potential in testicular seminoma.

Testicular anaplastic seminoma, which has a high mitotic activity, is regarded as more malignant than typical seminoma, although its prognosis is still unclear. To determine whether seminoma with relatively greater malignancy potential can be identified based on the cell proliferative activity, the mitotic rate (MR; mitotic count per high-power field), mitotic index (MI; mitotic count per 1000 cells), Ki-67 labeling index (Ki-67 LI; the percentage of positive cells) and proliferating cell nuclear antigen LI (PCNA LI; the percentage of positive cells) were histologically examined in 44 patients. The MI, Ki-67 LI and PCNA LI in patients with metastatic disease were significantly higher than those in patients without metastatic disease, and the MI in patients with fatal disease was significantly higher than those in patients cured of the disease. However, these distributions of the MI, Ki-67 LI and PCNA LI values overlapped for both pairs of groups. There were no significant differences in the MR. These results suggest that the cell proliferative activity makes a small contribution to the malignancy potential in testicular seminoma, with the activity being not necessarily indicative of metastasis and prognosis.

Adolescent↗
PubMed1997

Immunohistochemical analysis of the nm23 gene products in testicular seminoma.

The nm23 gene has been identified as a metastasis suppressor gene. To clarify the role of nm23 as a metastasis suppressor gene in testicular seminoma, the expression of the nm23-H1 and -H2 proteins (human nucleoside-diphosphate kinase-A and -B) was immunohistochemically examined in 43 patients. Thirty-six (84%) and 21 (49%) of the 43 primary tumors were positive for the nm23-H1 and -H2 proteins, respectively. There was no significant difference in either nm23-H1 or -H2 expression between the 24 primary non-invasive tumors and the 19 primary invasive tumors, or between the 31 primary tumors without metastasis and the 12 primary tumors with metastasis. In all, and 5 of 6 metastatic tumors, the expression of nm23-H1 and -H2 proteins was observed, respectively, and the expression was not decreased in the metastatic tumors, compared to the primary tumors. In conclusion, the immunohistochemical expression of both the nm23-H1 and -H2 gene products is not associated with the metastatic status or the invasive status of testicular seminoma, and it is unlikely to be a useful non-metastatic indicator for testicular seminoma. Further studies are needed to elucidate the biological role of nm23.

Adolescent↗
PubMed1997

Testicular seminoma with human chorionic gonadotropin production.

Testicular seminoma with elevated serum human chorionic gonadotropin level (hCG-positive seminoma) is regarded as more malignant than marker-negative seminoma, although its prognosis is still unclear. To clarify the malignant potential of seminoma with hCG production, the serum levels of the beta subunit of hCG (beta-hCG) and lactic acid dehydrogenase (LDH) were examined in 35 and 40 patients, respectively, and the immunohistochemical expression of beta-hCG examined in 45 tumors. The elevation of the LDH serum level correlated to the invasive status, metastatic status and poor outcome, while that of the serum beta-hCG level correlated only to the metastatic status. Immunohistochemical expression of beta-hCG was observed in syncytiotrophoblastic giant cells in 11 tumors and a few mononuclear seminoma cells in 36 tumors. Expression was not associated with the malignancy potential, except where the expression in mononuclear cells inversely correlated to the invasive status. These results suggest that most seminomas produce a slight amount of hCG; that an elevated hCG serum level indicates the presence of metastatic tumors and mainly reflects an increase in tumor volume but not in cellular malignancy potential; and that the LDH serum level, rather than hCG, is more useful as a prognostic indicator for patients with seminoma.

Adolescent↗
PubMed1997

Band heterotopia or double cortex in a male: bridging structures suggest abnormality of the radial glial guide system.

A moderately retarded Japanese boy, with a normal male karyotype (46,XY), was diagnosed to have a subcortical band heterotopia or double cortex syndrome. The band heterotopia was relatively thick compared with that of other patients reported. On T2-weighted coronal MR sections, there were numerous radial linear structures between the cortex and the band, probably representing the trace of radial fibers. He had no family members with seizures or mental retardation. Over 50 described patients with this malformation have been female except two patients briefly mentioned by several investigators. Band heterotopia or the double cortex syndrome is inherited as a sex-linked dominant condition. Affected mothers may have affected daughters or sons with lissencephaly, suggesting a link between these disorders. This is the first detailed description of a male with band heterotopia.

Cell Movement↗
PubMed1997

Development of a fluorescent indicator for the bioimaging of nitric oxide.

Nitric oxide (NO) has been reported to play various roles as a signal transmitter. However, detailed functions of NO have yet to be clarified. We have developed a fluorescent indicator for NO imaging in living cells. The N-nitrosation of newly designed and synthesized 4-((3-amino-2-naphthyl)aminomethyl)benzoic acid (DAN-1) by NO yielded the highly fluorescent triazole-form. The membrane permeable ester derivative of DAN-1 (DAN-1 EE) was applied to the imaging of NO produced in activated rat aortic smooth muscle cells. After DAN-1 EE has been loaded into cells, the ester bond is hydrolyzed by intracellular esterase, yielding original DAN-1 with less permeability. The fluorescence intensity of the cells loaded with DAN-1 EE increased according to NO production. The imaging method with fluorescent indicators will be significant for the functional clarification of NO in vivo.

2-Naphthylamine↗
PubMed1997

Suppression of ischemic edema in mice by manganese-hyaluronate conjugate.

Manganese-hyaluronate conjugate (Mn-HA) was synthesized from a diethylenetriaminepenta-acetic acid derivative of hyaluronic acid and manganese ion. The conjugate markedly scavenged super-oxide anion in vitro and exhibited much higher anti-inflammatory activity than superoxide dismutase in suppressing paw edema in mice when intravenously injected 30 min before the initiation of ischemia.

Animals↗
PubMed1997

[Preliminary evaluation of the apparent diffusion coefficient of the kidney with a spiral IVIM sequence].

We examined the usefulness of the spiral intravoxel incoherent motion (IVIM) sequence in measuring the apparent diffusion coefficient (ADC) of the kidneys. Five volunteers and five patients with chronic renal failure underwent diffusion-sensitive magnetic resonance imaging of the kidneys with the spiral IVIM sequence. The ADC values in patients with chronic renal failure were significantly lower than those in the renal cortex of volunteers. The mean value of ADC in patients with chronic renal failure was lower than that in volunteers, although there was no statistically significant difference. In volunteers, the ADC of the renal cortex was significantly higher than that of the renal medulla. The phantom study indicated that the accuracy of ADC depended on the signal to noise ratio. A spiral IVIM sequence with a high enough signal to noise ratio may be useful in evaluating renal function especially that of the cortex.

Adult↗
PubMed1997

Condylar surface forms in edentulous patients: examination findings.

The incidence of abnormal condylar surface forms was assessed by zonograms on edentulous patients who visited this department with various chief complaints other than temporomandibular disorder. The relation between these abnormal condylar surface forms and the conditions involved in the manifestation of the abnormalities was studied. Abnormal condylar surface forms were observed in 71% of the subjects. Bilateral abnormalities were found in 66% of these subjects: These abnormalities were classified into four types: erosion, flattening, osteophyte, and concavity. Those with erosion showed the highest incidence at 60.6%. The incidence of abnormal condylar surface forms was significantly higher in patients over 70 years old and/or in unstable denture wearers.

Age Factors↗
PubMed1996

Heparan sulfate proteoglycan on leukemic cells is primarily involved in integrin triggering and its mediated adhesion to endothelial cells.

Leukocyte migration from circulation into tissue depends on leukocyte integrin-mediated adhesion to endothelium, but integrins cannot function until activated. However, it remains to be understood how tumor cells adhere to endothelium and infiltrate into underlying tissue. We studied mechanisms of extravasation of leukemic cells using adult T cell leukemia (ATL) cells and report the following novel features of cell surface heparan sulfate proteoglycan on ATL cells in ATL cell adhesion to endothelium: ATL cells adhere to endothelial cells through already activated integrins without exogenous stimulation; different from any other hematopoietic cells, ATL cells express a characteristic heparan sulfate capable of immobilizing heparin-binding chemokine macrophage inflammatory protein (MIP)-1 beta, a potent T cell integrin trigger, produced by the cells themselves; competitive interruption of endogenous heparan sulfate proteoglycan synthesis reduces cell surface MIP-1 beta and prevents ATL cells from integrin-mediated adhesion to endothelial cells or intercellular adhesion molecule-1 triggered through G-protein. We propose that leukemic cells adhere to endothelial cells through the adhesion cascade, similar to normal leukocyte, and that the cell surface heparan sulfate, particularly on ATL cells, is pivotally involved in chemokine-dependent autocrine stimulation of integrin triggering by immobilizing the chemokine on them.

CD4-Positive T-Lymphocytes↗
PubMed1996

Occurrence of nuclear-encoded tRNAIle in mitochondria of the liverwort Marchantia polymorpha.

Although 29 tRNA genes have been deduced from the complete nucleotide sequence of the mitochondrial genome from the liverwort Marchantia polymorpha, a tRNAIle gene decoding AUU and AUC codons is conspicuously absent. In order to address the question of the possible involvement of nuclear-encoded tRNA, we isolated and identified three variant copies of the nuclear-encoded tRNAIle(AAU) gene from the liverwort. Northern analysis showed the presence of nuclear-encoded tRNAIle both in the mitochondrion and the cytosol, while both chloroplast DNA-encoded tRNAIle and nuclear-encoded tRNATyr were absent in liverwort mitochondria. These results unequivocally establish that import of nuclear tRNAIle into mitochondria indeed occurs in one of the most primitive plants, M. polymorpha.

Base Sequence↗
PubMed1996

Production of a novel monoclonal antibody, JT-95, which can detect antigen of thyroid carcinoma.

Monoclonal antibody (MAb) JT-95 was produced by immunization of mice with membrane fractions of a human thyroid carcinoma. Immuno-histochemical staining has demonstrated that the antigen recognized by JT-95 is strongly expressed in 95 (95%) of 100 cases of papillary carcinomas and in 3 (75%) of 4 cases of follicular carcinomas. In benign diseases of the thyroid gland, MAb JT-95 reacted with 0 (0%) of 39 adenomas, 1 (4%) of 21 adenomatous goiters, 0 (0%) of 8 hyperthyroidism specimens, and 3 (38%) of 8 chronic thyroiditis specimens. The antigen detected by MAb JT-95 has an apparent Mr 250,000 in thyroid carcinomas. Moreover, circulating antigen in thyroid carcinoma patients was detected by MAb JT-95 in an ELISA and in Western blotting. The circulating antigen has a Mr 105,000. MAb JT-95 conjugated with (131) I was administrated to nude mice bearing a human thyroid carcinoma. JT-95 131I accumulation at the transplanted tumor was visualized by autoradiography with 2.68-14.75-fold higher levels detected at the xenograft compared to that for normal organs. Based on these data, MAb JT-95 may be useful in the diagnosis detection and therapy of thyroid carcinoma.

Adenocarcinoma, Follicular↗
PubMed1996

Inhibition of microsomal lipid peroxidation by baicalein: a possible formation of an iron-baicalein complex.

Baicalein decreased the production of thiobarbituric acid reactive substances, the rate of oxygen consumption and iron reduction in the reaction system of ascorbic acid with FeCl3. Superoxide dismutase, catalase and hydroxyl radical scavengers had no significant effect. Iron-chelators had an inhibitory effect similar to that of baicalein. The production of thiobarbituric acid reactive substances of baicalein-treated microsomes obtained by centrifugation after incubation with baicalein was not observed in the reaction system, but was stimulated by adding iron with increases in concentration. The amount of bound iron to microsomal membranes increased by increasing both the concentration of baicalein and iron. The amount of baicalein bound to microsomal membranes increased with increasing concentration of added baicalein. These results suggest that baicalein bound to microsomal membranes inhibits lipid peroxidation by formating an iron-baicalein complex.

Animals↗