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Biomedical subjects

H Shimizu

Publications and source records attributed to H Shimizu.

At least 109 records · Page 6Linked to original sources
PubMed2002

Soy product intake and serum isoflavonoid and estradiol concentrations in relation to bone mineral density in postmenopausal Japanese women.

To evaluate soy intake and serum concentrations of estradiol and isoflavonoids and their relationship to bone mineral density (BMD) and serum bone-specific alkaline phosphatase (bone ALP) activity, we conducted a cross-sectional study of 87 postmenopausal Japanese women. Soy product and isoflavone intake from soy products and intake of nutrients were assessed with a semiquantitative food-frequency questionnaire. BMD (mg/cm2) was measured by single-energy X-ray absorptiometry at the site of the calcaneus. Serum estradiol (E2) and the sex hormone-binding globulin (SHBG) were measured by radioimmunoassay. Serum genistein and daidzein concentrations were measured by a high-performance liquid chromatography MS/MS method. A statistically significant correlation was observed between the ratio of E2 to SHBG and BMD (Spearman r=0.38, p=0.0003) after controlling for age, body mass index, smoking status, age at menarche, and intake of vegetable fat, vitamin C and salt. Soy product and isoflavone intake and serum isoflavones were not significantly correlated with BMD after controlling for the covariates. Serum ALP was not significantly correlated with soy product and isoflavone intake, the E2/SHBG ratio or serum isoflavones. The present study supports the association of BMD with serum estradiol; however, it does not support the association of BMD with soy or isoflavone intake or serum isoflavone levels.

Adult↗
PubMed2002

(201)Tl-SPECT, (1)H-MRS, and MIB-1 labeling index of central neurocytomas: three case reports.

BACKGROUND: The proliferative activity and metabolic features of three central neurocytomas were investigated using the findings of thallium-201 single photon emission computed tomography ((201)Tl-SPECT) and proton magnetic resonance spectroscopy ((1)H-MRS), and the MIB-1 labeling index (MIB-1 LI). METHOD: The early and delayed (201)Tl indices were calculated as the ratio of tumour to normal brain tissue uptake by (201)Tl-SPECT. In vivo single-voxel (1)H-MRS was performed with echo time of 272 msec to evaluate the metabolites including choline (Cho), N-acetyl aspartate (NAA) and creatine/phosphocreatine (Cre). An external standard reference was used to semiquantitate each metabolite. MIB-1 LI was determined in the surgical specimens. FINDINGS: The MIB-1 LI was 0.5%, 1.2%, and 7.5% in an atypical central neurocytoma without intraventricular extension. Significant (201)Tl uptake was observed on delayed images in all three central neurocytomas. (1)H-MRS showed the high Cho peaks relative to the NAA and Cre peak. The signal at 3.55 ppm, which may be due to inositol or glycine, was observed in one central neurocytoma. INTERPRETATION: Both (201)Tl-SPECT and (1)H-MRS did not reflect the proliferative potential of central neurocytomas.

Adult↗
PubMed2002

Mold filling of titanium alloys in two different wedge-shaped molds.

Pure titanium and titanium alloys are potential materials for the fabrication of cast dental appliances. One important factor in producing sound castings is the capacity of the metal to fill the mold. This study used a wedge-shaped mold to compare the mold filling of titanium with that of conventional dental casting alloys. The metals used were CP Ti, Ti-6Al-7Nb, Ti-6Al-4V, Ti with 1 and 4wt% Cu and ADA Type III gold alloy and an Ni-Cr alloy. The castings were cut into four pieces parallel to the triangular surface. Mold filling was evaluated as the distance between the tip of the cast wedge and theoretical tip of the triangle. The mold filling of the gold alloy was superior compared to all the metals tested, while the mold filling of the Ni-Cr alloy was the worst. There were no statistical differences at the 30 degrees marginal angle for all the cast titanium metals. At the sharper 15 degrees angle, CP Ti and Ti-6Al-7Nb was superior to both the Ti-Cu alloys. Although the mold filling of titanium was inferior compared to the gold alloy, the data justify the use of titanium for the production of dental appliances.

Dental Alloys↗
PubMed2002

The relationship between the visually evoked P300 event-related potential and gamma band oscillation in the human medial and basal temporal lobes: an electrocorticographic study.

We have recorded electrocorticographic activities (ECoG) from subdural electrodes on the human medial temporal lobe (MTL) and basal temporal lobe (BTL) in epileptic patients during cognitive visual tasks designed to evoke the P300 event related potential (ERP). From those recordings we examined the event related gamma band oscillation (ERGBO) and P300 ERP. While P300 was predominantly observed in the MTL, ERGBO was observed in both MTL and BTL. Resembling to P300, ERGBO responses were more often observed following rare stimuli than frequent stimuli. In average responses the ERGBO to rare stimuli followed P300, beginning at 440.5 ms and continuing for about 100 ms. Past studies suggest P300 ERP component reflects a role in cognitive function. Since ERGBO in the present study appeared in different regions and at a different latency from P300, ERGBO may reflect a different physiological role in the cognitive process.

Adult↗
PubMed2002

Massive cell death of cerebellar granule neurons accompanied with caspase-3-like protease activation and subsequent motor discoordination after intracerebroventricular injection of vincristine in mice.

Vincristine, a microtubule-depolymerizing agent, is known to induce neuronal cell damage. Biochemical, histological and behavioral alterations were investigated after intracerebroventricular injection of vincristine in mice. Intracerebroventricular injection of vincristine caused caspase-3-like protease activation followed by nucleosomal release in the cerebellum. Histological examinations showed that vincristine-induced damage was relatively specific to granule cells in the cerebellum, and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling-positive cells were observed among these cells. Chromatin condensation, one of the criteria for apoptosis, was seen on electron microscopy. Behavioral changes, namely head movements, pivoting and backward walking, were observed in parallel with the increase of caspase-3-like protease activity and nucleosomal release. Furthermore, motor function tests (bulb balance test and rotating rod test) showed deficits of motor coordination ability. These observations suggest that intracerebroventricular vincristine causes massive apoptosis of cerebellar granule cells accompanied with caspase-3-like protease activation, leading to motor dysfunction, in this model. These vincristine-treated mice should be a useful in vivo model for examination of neuronal apoptosis, which might be involved in a variety of neurodegenerative diseases.

Animals↗
PubMed2002

Feeding and wounding responses in Hydra suggest functional and structural polarization of the tentacle nervous system.

The nervous system of Hydra, a freshwater cnidaria, occurs as dispersed, or diffuse, nerve net throughout the animal. It is widely accepted that in a diffuse nervous system an external stimulus is conducted in all directions over the net. Here I report observations that hydra tentacles respond to feeding and wounding stimuli in a unidirectional manner. Upon contact of a tentacle with a brine shrimp larva during feeding, tissue on the proximal side of the point of contact contracted strongly, whereas tissue on the distal side contracted only very weakly. Feeding a tentacle to which a second tentacle was grafted to the proximal end in the reversed orientation showed that unidirectional conduction, once initiated, was blocked by the reversal of polarity, demonstrating that the distal to proximal polarity of tissue is crucial for unidirectional conduction. Unidirectional conduction was obtained also by mechanically pinching the tissue. The response of tentacles devoid of neurons examined was bidirectional, demonstrating that the nervous system is responsible for the unidirectional responses. These observations suggest that polarized property of the nerve net in hydra tentacles is responsible for the unidirectional tentacle contraction.

Animals↗
PubMed2002

Association between serotonin 4 receptor gene polymorphisms and bipolar disorder in Japanese case-control samples and the NIMH Genetics Initiative Bipolar Pedigrees.

Possible irregularities in serotonergic neurotransmission have been suggested as causes of a variety of neuropsychiatric diseases. We performed mutation and association analyses of the HTR4 gene, on 5q32, encoding the serotonin 4 receptor in mood disorders and schizophrenia. Mutation analysis was performed on the HTR4 exons and exon/intron boundaries in 48 Japanese patients with mood disorders and 48 patients with schizophrenia. Eight polymorphisms and four rare variants were identified. Of these, four polymorphisms at or in close proximity to exon d, g.83097C/T (HTR4-SVR (splice variant region) SNP1), g.83159G/A (HTR4-SVRSNP2), g.83164 (T)9-10 (HTR4-SVRSNP3), and g.83198A/G (HTR4-SVRSNP4), showed significant association with bipolar disorder with odds ratios of 1.5 to 2. These polymorphisms were in linkage disequilibrium, and only three common haplotypes were observed. One of the haplotypes showed significant association with bipolar disorder (P = 0.002). The genotypic and haplotypic associations with bipolar disorder were confirmed by transmission disequilibrium test in the NIMH Genetics Initiative Bipolar Pedigrees with ratios of transmitted to not transmitted alleles of 1.5 to 2.0 (P = 0.01). The same haplotype that showed association with bipolar disorder was suggested to be associated with schizophrenia in the case-control analysis (P = 0.003) but was not confirmed when Japanese schizophrenia families were tested. The polymorphisms associated with mood disorder were located within the region that encodes the divergent C-terminal tails of the 5-HT(4) receptor. These findings suggest that genomic variations in the HTR4 gene may confer susceptibility to mood disorder.

Adolescent↗
PubMed2002

Formation of cornified cell envelope in human hair follicle development.

BACKGROUND: Cornified cell envelope (CCE) formation is an important step in the final stage of keratinization, in which CCE precursor proteins including involucrin and loricrin are cross-linked by keratinocyte transglutaminases (TGases) to the inner surface of the plasma membrane of cornified cells, while the outer surface is coated with material derived from secreted lamellar granules. OBJECTIVES: Skin samples from human fetuses of a series of estimated gestational age (EGA) (49-163 days) were studied for the prescence of precursor proteins. Methods TGase activity was studied by in situ TGase activity assay, and ultrastructural features of CCE formation were observed at each stage of hair follicle development. We used immunofluorescent labelling to investigate the time and site of expression of CCE precursor proteins involucrin and loricrin, TGases 1, 2 and 3, and a 25-kDa lamellar granule-associated protein (LGP) in developing human hair follicles. RESULTS: In the hair germ (65-84 days EGA) (corresponding to the stages 1-2 of murine hair follicle morphogenesis), only TGase 2 was observed in the entire hair germ, where in situ TGase activity was weakly positive, although thickening of cell membrane was not seen ultrastructurally. In the hair peg (85-104 days EGA) (corresponding to the stage 3 of murine hair follicle morphogenesis), loricrin and TGase 2 were seen in cells of the upper part of the hair peg while TGase 1, 3 and LGP were observed in the inner cells of the hair peg. In situ TGase activity was weakly positive in the upper part and inner cells of the hair peg. In the bulbous hair peg (105-135 days EGA) (corresponding to the stages 4-6 of murine hair follicle morphogenesis) and differentiated lanugo hair follicle (> 135 days EGA) (corresponding to the stages 7-8 of murine hair follicle morphogenesis), immunoreactivities of involucrin, loricrin, TGase 1, 2, 3, in situ TGase activity and LGP were detected in the inner root sheath cells, hair canals and inner cells of the outer root sheath in the region of the isthmus. Ultrastructurally, thickening of cell membrane was already seen in the inner root sheath cells of the bulbous hair peg and electron-dense, thick CCE was observed in the hair cuticle and hair canal of differentiated lanugo hair follicle. CONCLUSIONS: These data indicate that, in terms of CCE formation, certain portions of the developing human hair follicle have already been determined in differentiation of the hair canal and cuticle at the hair peg stage.

Cell Differentiation↗
PubMed2002

A novel A97P amino acid substitution in alpha-galactosidase A leads to a classical Fabry disease with cardiac manifestations.

BACKGROUND: Fabry disease results from a genetic deficiency of alpha-galactosidase A (GLA) activity. Phenotype-genotype correlations in this condition have not as yet been fully elucidated. OBJECTIVE: To report a case of a male patient with classical Fabry disease and his mother, a heterozygous female with Fabry disease, showing cardiac involvement, and to identify the underlying GLA gene mutation in this particular phenotype. PATIENTS/METHODS: Genomic DNA was extracted from the patient, his mother and the unaffected family members. Biopsy specimens of skin, heart and kidney were examined using light and electron microscopy. The mutation was identified by polymerase chain reaction and direct sequencing and was confirmed by restriction enzyme fragment length polymorphism. RESULTS: The G-->C transversion was identified in codon 97 of the GLA gene and resulted in an A97P amino acid substitution that was a novel pathogenic GLA gene mutation. The male patient who had classical Fabry disease was hemizygous and his mother was heterozygous for this mutation. CONCLUSIONS: These results indicate that the A97P amino acid substitution in GLA might tend to induce classical Fabry disease.

Adult↗
PubMed2002

Results of surgical treatment for intrahepatic cholangiocarcinoma and clinicopathological factors influencing survival.

BACKGROUND: The results of surgical treatment for intrahepatic cholangiocarcinoma (ICC) and specific factors influencing survival are still unclear. METHODS: Between 1984 and 2001, 62 patients with ICC underwent laparotomy, with a 77 per cent (48 patients) resectability rate. The tumours in these 48 patients were reviewed retrospectively to examine the relationship between gross appearance (mass forming, periductal infiltrating, intraductal growth, and mass forming plus periductal infiltrating) and patient survival, as well as the manner of recurrence. In patients with mass-forming and mass-forming plus periductal infiltrating types, univariate and multivariate analyses of potential prognostic factors were performed. RESULTS: The 1-, 3- and 5-year survival rates were 62, 38 and 23 per cent respectively. All patients with the intraductal growth type remained alive after intervals ranging from 8 to 72 months. Univariate analysis showed multiple hepatic lesions, liver capsule invasion, presence of cancer cells in the resection margin, and high serum carbohydrate antigen (CA) 19-9 level to be significant negative prognostic factors. Lymph node involvement, however, was not identified as a significant prognostic factor. With multivariate analysis, multiple hepatic lesions and high serum CA19-9 concentration were found to be significantly related to prognosis. The most frequent recurrence site was the remnant liver. CONCLUSION: These results suggest that the intraductal growth type of tumour should be treated as a distinct entity compared with other types of ICC. Multiple tumours and high serum CA19-9 level were signs of dismal prognosis, whereas not all patients with lymph node involvement had a poor prognosis.

Adult↗
PubMed2002

Diagnosis of Werner syndrome by immunoblot analysis.

Werner syndrome (WS) is caused by mutations in the gene encoding RecQ type DNA helicase (WRN). We report a 53-year-old Japanese male with WS who initially presented with skin ulcers on the feet and the left elbow. The patient had a high-pitched voice, hoarseness, a characteristic bird-like facial appearance with a beak-shaped nose, canities and juvenile cataracts. Immunoblot analysis using a monoclonal antibody directed against the WS gene product DNA helicase revealed that the patient's leucocytes lacked this particular molecule, confirming the diagnosis of WS. This new immunoblot system therefore enables the diagnosis of WS to be made without the need to undertake more complex mutational analysis.

DNA Helicases↗
PubMed2002

Direct injection of naked DNA and cytokine transgene expression: implications for keratinocyte gene therapy.

Intradermally injected DNA diffuses into the epidermis and can then enter keratinocytes and become expressed by these cells. Using this method, plasmids containing cytokine genes that have been introduced into keratinocytes can induce a level of cytokine expression sufficient to provide biological effects in the treated skin. Furthermore, transgenic cytokines released from the transduced keratinocytes can also enter the circulation and have downstream effects on other target organs. Thus far, naked DNA injection appears to be a safe, simple, and relatively efficient method that enables genes to be expressed in transplanted human skin on immunosuppressed animals. In humans, keratinocyte gene therapy using the cytokine gene DNA injection method has the potential to become a powerful therapeutic tool for dermatologists in the management of certain inflammatory and other dermatoses.

Biolistics↗
PubMed2002

Liver dysfunction among workers handling 5-nitro-o-toluidine.

BACKGROUND: 5-Nitro-o-toluidine is an aromatic nitro amino compound. While other aromatic compounds are known to damage the human liver and are registered as toxic substances, toxicity information concerning 5-nitro-o-toluidine is lacking. AIMS: To investigate the hepatotoxicity of 5-nitro-o-toluidine. PATIENTS AND METHODS: Of 15 workers in the same factory who handled 5-nitro-o-toluidine, three were hospitalised with symptoms of acute liver dysfunction. Suspecting a link between liver dysfunction and working conditions, we correlated workplace factors with clinical findings in all 15 workers. RESULTS: Blood biochemistry tests indicated liver damage in seven of 15 study subjects. Workers who handled 5-nitro-o-toluidine and nitrosyl sulphuric acid often loosened their respiratory protective equipment shortly after 5-nitro-o-toluidine powder had been dispersed into the air of the room. No potential hepatotoxins were present except for 5-nitro-o-toluidine. Six of the affected workers had handled 5-nitro-o-toluidine 12 to 20 times; the seventh worker had handled the powder three times; and the other eight workers without liver dysfunction had handled the material once or twice. No other significant differences in background were evident between the affected and unaffected workers, such as age, sex, or protective measures. Histological findings during recovery from liver damage were similar to those of acute viral hepatitis. None of the 15 subjects has demonstrated liver damage since the factory was closed. CONCLUSIONS: A link between liver dysfunction and 5-nitro-o-toluidine exposure is suggested by greater severity of liver dysfunction associated with more episodes of handling.

Acute Disease↗