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Biomedical subjects

S Takai

Publications and source records attributed to S Takai.

At least 253 records · Page 14Linked to original sources
PubMed1992

Virulence-associated 15- to 17-kilodalton antigens in Rhodococcus equi: temperature-dependent expression and location of the antigens.

Virulent Rhodococcus equi showing 15- to 17-kDa antigens, which is virulent in mice, was found to harbor an 85-kbp plasmid, and the 15- to 17-kDa antigens were found to be associated with possession of the 85-kbp plasmid of R. equi (S. Takai, T. Sekizaki, T. Ozawa, T. Sugawara, Y. Watanabe, and S. Tsubaki, Infect. Immun. 59:4056-4060, 1991). The expression of these antigens was temperature regulated: when cells were grown at a low temperature (25 to 32 degrees C), they did not express them, whereas they expressed them in large amounts when the cells were grown at a higher temperature (34 to 41 degrees C). The antigens were expressed on the cell surface, as evidenced by their susceptibility to proteolysis by a trypsin and by the biotin-avidin protein-blotting technique.

Antigens, Bacterial↗
PubMed1992

Rigid spine syndrome with selective respiratory muscle weakness.

Rigid spine syndrome is a rare myopathy characterized by mild axial and proximal muscle weakness, limitation of neck and trunk flexion, scoliosis and mild joint contractures. We describe a 20-year-old woman with this syndrome who developed severe respiratory muscle failure disproportionate to the well-preserved extremity muscles. Nocturnal home care ventilation has completely restored her arterial oxygen desaturation during a 5-year follow-up.

Adult↗
PubMed1992

Interferon-gamma reduces the thyroid peroxidase content of cultured human thyrocytes and inhibits its increase induced by thyrotropin.

To clarify the role of interferon-gamma (IFN gamma) in autoimmune thyroid diseases, we investigated the effects of IFN gamma on the content of thyroid peroxidase (TPO) and the expression of HLA-DR antigens in cultured normal human thyrocytes. The effect of TSH on the action of IFN gamma was investigated. Immunofluorescence staining and photometric analysis showed that IFN gamma not only induced the expression of DR antigen, but also reduced the content of TPO in a concentration-dependent manner. The addition of TSH increased the content of TPO and enhanced the IFN gamma-induced expression of DR antigen. IFN gamma also inhibited the increase in TPO content induced by TSH. Thus, complex interactions appear to exist between IFN gamma and TSH or thyroid-stimulating antibodies in the modulation of hormone secretion and autoimmune phenomena in the thyroid.

Adenoma↗
PubMed1992

Identification and analysis of the ret proto-oncogene promoter region in neuroblastoma cell lines and medullary thyroid carcinomas from MEN2A patients.

The human ret proto-oncogene (proto-ret), encoding a receptor tyrosine kinase, is highly expressed in neuroblastomas, medullary thyroid carcinomas (MTCs) and pheochromocytomas, which are all tumors of cells originating from the neural crest. In studies on the transcription mechanism of proto-ret, we identified the transcription start site and the promoter region by chloramphenicol acetyl transferase (CAT) assay. A sequence upstream from the transcription start site (-167 to +98 bp) showed definite promoter activity in both proto-ret mRNA-positive neuroblastoma NB39-nu cells and proto-ret mRNA-negative HeLa cells. The promoter sequence had a high GC content and contained four tandemly repeated GC boxes without a TATA box. Putative binding sequences for SP-1, AP-2 and epidermal growth factor receptor-specific transcription factor (ETF) and also the transcription-suppressing factor, GC factor (GCF), were found in the repeated GC box region. Southern blot analysis of DNAs of neuroblastoma cell lines and primary MTCs showed that the high proto-ret expression in these tumors is not caused by gross genetic changes in the promoter region, suggesting the possible involvement of a region(s) other than the sequence from -167 to +98 bp or a minor genetic change(s) in the promoter region.

Amino Acid Sequence↗
PubMed1992

Expression of the ret proto-oncogene in human medullary thyroid carcinomas and pheochromocytomas of MEN 2A.

We studied the expression of the ret proto-oncogene (proto-ret) in human medullary thyroid carcinomas (MTCs) and pheochromocytomas of multiple endocrine neoplasia type 2A (MEN 2A) by Northern blot analysis. Expression of the normal-sized transcripts was detected in all 12 MTCs and in 6 of 8 pheochromocytomas. In situ localization of proto-ret mRNA revealed that the signal was confined to the cytoplasm of MTC cells. By Southern blot analysis neither amplification nor gross genetic changes of proto-ret were found in the tumors. Although no transcripts were detected in the normal portion of the thyroid from one MEN 2A patient, faint signals were detected in normal adrenal glands by Northern blot analysis, probably due to minor populations of C-cells and chromaffin cells in specimens from which MTC and pheochromocytoma might later develop. Proto-ret may play an important role in differentiation of a specific cell lineage from neuroectoderm, and it may be involved in development of MEN 2A tumors.

Adrenal Gland Neoplasms↗
PubMed1992

[A case of advanced breast cancer with multiple organ metastases successfully treated by tamoxifen].

A 66-year-old postmenopausal woman presented in June 1991 with a giant ulcerated left breast tumor. She had discovered the tumor two years previously, but had never visited any medical institution. She was diagnosed as advanced breast cancer with multiple lung metastases, bone metastasis, and both supraclavicular lymph node metastases by physical examination, fine needle aspiration cytology, chest X-P, and bone scintigraphy. Incisional biopsy, performed to confirm the histological type of breast cancer and to evaluate estrogen and progesterone receptor (ER and PgR) status, revealed solid-tubular carcinoma. Both ER and PgR were highly positive at 322.6 and 228.0 fmol/mg protein, respectively. Therefore, endocrine therapy was chosen to treat this advanced breast cancer patient, although she had multiple organ metastases. Twenty mg of Tamoxifen a day was administered per os. After treatment with tamoxifen, the size of ulceration started to decreased and the dyspnea caused by multiple lung metastases was reduced. Eight weeks after, she showed partial response (PR) determined from the size of the ulceration and chest X-P. She has been maintaining PR for more than 9 months. Thus, Tamoxifen was shown to be very effective for this case of advanced breast cancer with multiple organ metastases.

Adenocarcinoma↗
PubMed1991

Expression of alpha-amylase isozymes in human thyroid tissues.

Expression of alpha-amylase genes in thyroid tissues was studied by assaying the total amylase activity as well as by using immunohistochemical and Northern blot analysis. The amylase genes expressed were determined by a combination of the polymerase chain reaction (PCR) and blot analysis using synthetic probes specific for the three known amylase isozyme complementary DNAs. The samples consisted of tissues from 18 human thyroid carcinomas (11 well-differentiated carcinomas, 2 poorly differentiated carcinomas, 1 anaplastic carcinoma, and 4 medullary carcinomas) and 9 specimens of nonmalignant thyroid tissue (2 were from nontumorous regions of resected glands and 7 were thyroid tissue from a patient with Graves' disease). Salivary-type amylase was expressed at a relatively high level in nonmalignant thyroid tissue and well-differentiated carcinoma and could be detected by Northern blot analysis. In poorly differentiated carcinoma, it was detected only by the PCR, while in anaplastic or medullary carcinoma, it was not detected even by the PCR. Thus, the expression of salivary-type amylase was characteristic of well-differentiated follicular cells. These observations suggest that salivary-type amylase expression may be a marker for identifying the histogenesis and stage of differentiation of thyroid cancer. In addition, the AMY2B gene product was detected in all different types of cells examined, although its expression was only detectable by the PCR. Pancreatic type amylase was not detected in any of the samples.

Adult↗
PubMed1991

Plasminogen activators in human gastric cancers: correlation with DNA ploidy and immunohistochemical staining.

Plasminogen activator activity was investigated in extracts of 42 surgically removed gastric carcinomas. The mean levels of total plasminogen activator (total-PA) and urokinase-type plasminogen activator (u-PA) activities in the gastric carcinomas were significantly higher than those in the background normal tissues (p less than 0.001). On electrophoresis, gastric cancers were found to contain u-PA as the predominant PA, this being confirmed using zymography by direct inhibition with anti-urokinase antibody. Assessment of the relationship between PA activity and biological behavior of gastric cancer revealed total-PA and u-PA levels to be significantly higher in differentiated than in undifferentiated tumors (p less than 0.001), and in aneuploid than in diploid ones (p less than 0.01). Immunohistochemical staining showed that the proportion of u-PA-positive cancer cells in the carcinoma tissues also correlated with activity as measured by the azocaseinolytic method. These findings suggest that the study of PA contents in gastric cancer, combined with a nuclear DNA ploidy and immunohistochemical analysis, might be useful for understanding the biological characteristics of the tumor.

Adult↗
PubMed1991

Incidence of prominent corneal nerves in multiple endocrine neoplasia type 2A.

We studied the increased visibility of corneal nerves inside an 8-mm diameter central corneal area in 14 patients with multiple endocrine neoplasia type 2A, one patient with multiple endocrine neoplasia type 2B, five patients with nonhereditary medullary thyroid carcinoma, ten patients with anterior keratoconus, and ten normal subjects. We used a grading system (grade 0 through grade 4) for nerve visibility based on slit-lamp biomicroscopic examination and photographic documentation. All 20 normal eyes showed either grade 0 or grade 1, which indicated no pathologic thickening of corneal nerves. Sixteen of the 28 eyes (57%) with multiple endocrine neoplasia type 2A, however, were evaluated as grade 2 or higher, which indicated thickened corneal nerves. The incidence of high nerve visibility in eyes with multiple endocrine neoplasia type 2A was significantly greater compared to normal eyes (P less than .0001), anterior keratoconus (P less than .0001), and nonhereditary medullary thyroid carcinoma (P = .0012). Furthermore, eight of the 28 eyes (29%) with multiple endocrine neoplasia type 2A showed markedly prominent corneal nerves (grade 3 and 4), a prominence similar to those seen in eyes with multiple endocrine neoplasia type 2B. There was no definite relationship among prominent nerve, age of the patient, and occurrence of pheochromocytoma. These findings suggest that over half of all patients with multiple endocrine neoplasia type 2A show corneal nerves pathologically thickened to different degrees.

Adult↗
PubMed1991

The effects of frequency and duration of controlled passive mobilization on tendon healing.

This study was designed to determine the effects of frequency and duration of controlled passive motion on the healing flexor tendon following primary repair. Adult mongrel dogs were divided into two groups based on frequency of controlled passive motion. In one group, motion was applied manually at a frequency of 12 cycles/min for 5 min/day; in the other group, a continuous passive motion machine was used to apply motion at a lower frequency of 1 cycle/min for 60 min/day, making the number of cycles each day for both groups identical. Gliding function and tensile properties of repaired tendons were evaluated biomechanically at 3 and 6 weeks postoperatively. Results showed that gliding function in both groups was similar, but tensile properties, as represented by linear slope, ultimate load, and energy absorption, were significantly improved in the higher frequency group. It was concluded that frequency of controlled passive motion rehabilitation is a significant factor in accelerating the healing response following tendon repair, and higher frequency-controlled passive motion has a beneficial effect.

Analysis of Variance↗
PubMed1991

Immunohistochemical analysis of plasminogen activator expression in human colorectal carcinomas: correlation with CEA distribution and tumor cell kinetics.

Fifty cases of colorectal adenocarcinoma were immunohistochemically examined for the relationship between distribution of plasminogen activators (PAs) and the degree of differentiation of cancer cells as reflected by carcinoembryonic antigen (CEA) expression as well as tumor cell kinetics. The A chain of urokinase-type PA (u-PA-A) was mainly observed in the apical portions of highly differentiated cancer cells. Increased expression and change in localization to the cytoplasm were found with progressive dedifferentiation. The numbers of DNA polymerase alpha (pol. alpha) positive cancer cells also increased in line with u-PA-A expression. The B chain of u-PA (u-PA-B), and the A and B chains of tissue-type PA (t-PA-A and -B) did not show similar alteration. The present findings suggest that the distribution of u-PA-A in colorectal carcinoma tissues, the degree of tumor differentiation, and the proliferation kinetics of cancer cells are closely related.

Adenocarcinoma↗
PubMed1991

Preclinical detection of MEN 2A gene carrier using linked DNA markers.

We have performed preclinical risk estimation of multiple endocrine neoplasia type 2A (MEN 2A) by using the polymorphic DNA markers tightly linked to the MEN2A locus. The gene for MEN 2A has been assigned to the pericentromeric region of chromosome 10 by linkage analysis. The preclinical detection of gene carriers in MEN 2A families using tightly linked DNA markers is useful for surgical treatment at an early stage. The DNA markers, RBP3 (retinol-binding protein 3, interstitial) and FNRB (fibronectin receptor, beta polypeptide), are both tightly linked to the MEN2A locus, and are localized to opposite sides of the MEN2A locus. We have used RBP3 and FNRB as markers for preclinical diagnosis. Of 18 Japanese families with MEN 2A, 6 families are informative for both loci, and other 10 families are informative for either RBP3 or FNRB. In one informative family, a 20-year-old female is predicted to be the gene carrier (probability; about 99%). She should be carefully followed up till full penetrance age. We conclude that DNA-based prediction of MEN 2A is an effective procedure for clinical use.

Asian People↗
PubMed1991

Contribution of the activation of the ras oncogene to the evolution of aldosterone- and renin-secreting tumors.

The possible point-mutational activation of the ras oncogene, which probably contributes to the evolution of aldosterone-producing adenomas and ectopic reninoma, was evaluated. Chromosomal DNA was extracted from six aldosterone-producing adenomas and one renin-secreting liver carcinoma, using the standard method with phenol:chloroform:isoamyl alcohol. One microgram of sample DNA, forward and reverse primers, Taq I polymerase and deoxyribonucleotide triphosphates (dNTPs) were mixed and the ras gene was amplified by the polymerase chain reaction. Point mutations at ras-12 or ras-61 sites of amplified DNA were tested by dot-blotting, using H-, N- and K-ras oligonucleotide probes with mutations at codons 12 or 61. However, there were no point mutations at amino acid codons 12 or 61 of c-Hi-ras, c-Ki-ras and N-ras oncogenes in all aldosterone-producing adenomas and the one ectopic reninoma. These results indicate that point-mutational activation of ras oncogenes does not contribute, at least in this series, towards the evolution of aldosterone-producing adenomas and the reninoma.

Adenoma↗
PubMed1991

A case of pheochromocytoma associated with meningioma.

We have recently observed a rare case of pheochromocytoma associated with meningioma. To determine the mechanism of such a coexistence in this particular case, we compared the constitutional and pheochromocytoma genotypes of the patient using polymorphic four DNA markers, and we found a loss of heterozygosity at the D1S7 locus. A loss of heterozygosity at this locus has previously been reported by Mathew et al. in pheochromocytoma patients, and our results were in agreement with that study. Therefore the allelic deletion at the D1S7 locus may be an important step in the tumorigenesis of pheochromocytoma in this case.

Adrenal Gland Neoplasms↗
PubMed1991

The effects of knee motion and external loading on the length of the anterior cruciate ligament (ACL): a kinematic study.

A six-degrees-of-freedom mechanical linkage device was designed and used to study the unconstrained motion of ten intact human cadaver knees. The knees were subjected to externally applied varus and valgus (V-V) moments up to 14 N-m as well as anterior and posterior (A-P) loads up to 100 N. Tests were done at four knee flexion angles; 0, 30, 45, and 90 deg. Significant coupled axial tibial rotation was found, up to 21.0 deg for V-V loading (at 90 deg of flexion) and 14.2 deg for A-P loading (at 45 deg of flexion). Subsequently, the knees were dissected and the locations of the insertion sites to the femur and tibia for the anteromedial (AM), posterolateral (PL), and intermediate (IM) portions of the ACL were identified. The distances between the insertion sites for all external loading conditions were calculated. In the case when the external load was zero, the AM portion of the ACL lengthened with knee flexion, while the PL portion shortened and the intermediate (IM) portion did not change in length. With the application of 14 N-m valgus moment, the PL and IM portions of the ACL lengthened significantly more than the AM portion (p less than 0.001). With the application of 100 N anterior load, the AM portion lengthened slightly less than the PL portion, which lengthened slightly less than the IM portion (p less than 0.005). In general, the amount of lengthening of the three portions of the ACL during valgus and anterior loading was observed to increase with knee flexion angle (p less than 0.001).

Adult↗
PubMed1991

Association between a large plasmid and 15- to 17-kilodalton antigens in virulent Rhodococcus equi.

Rhodococcus equi strains showing 15- to 17-kDa antigens in immunoblots were found to be virulent in mice. To study the genes specific to these antigens in virulent R. equi, we compared plasmid profiles, immunoblot profiles, and murine pathogenicity profiles of 10 strains of R. equi. All the strains showing 15- to 17-kDa antigens contained a large plasmid of approximately 85 kbp and were virulent in mice; however, the remaining strains lacked both the antigens and the large plasmid and were avirulent in mice. Mutants of virulent strains ATCC 33701 and L1, which were cured of the large plasmid by repeated passage at 38 degrees C, lacked the 15- to 17-kDa antigens and showed a dramatic decrease in lethality in mice. These results suggested that the presence of an 85-kbp plasmid may be essential for virulence and expression of 15- to 17-kDa antigens of R. equi and offered support for earlier observations that freshly isolated strains of R. equi killed mice, whereas laboratory-adapted strains did not.

Actinomycetales Infections↗
PubMed1991

Prevalence of virulent Rhodococcus equi in isolates from soil and feces of horses from horse-breeding farms with and without endemic infections.

The prevalence of virulent Rhodococcus equi in isolates from soil and feces of foals on a farm with endemic R. equi infections was significantly higher than that of a farm with no history of the disease. Foals bred on a farm with the endemic disease might be constantly exposed to virulent R. equi in their environment.

Actinomycetales Infections↗