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Biomedical subjects

M Kuroda

Publications and source records attributed to M Kuroda.

At least 397 records · Page 22Linked to original sources
PubMed1988

Construction of a vector for the study of regulatory mechanism of gene expression and its utilization in the melibiose operon of Escherichia coli.

We constructed a vector to evaluate terminator or attenuator of transcription quantitatively. This vector is a plasmid possessing lac promoter-polylinker-CAT(chloramphenicol acetyltransferase) gene. DNA fragment of interest can be inserted into the polylinker site, and the effect of the DNA fragment on the expression of the downstream gene is evaluated from the CAT activity. We analyzed gene expression of the melibiose operon of Escherichia coli using this plasmid, and found that a DNA fragment containing a large stem-loop structure with boxA sequence in it, which was present between melA and melB, caused strong reduction of gene expression. This DNA portion seems to be responsible for reduced expression of melB, the second gene of the melibiose operon.

Cloning, Molecular↗
PubMed1988

Ameloblastoma of mucosal origin.

Histopathological, histochemical and ultrastructural findings of an extraosseous ameloblastoma occurring in an 89-year-old woman are reported. Rete pegs of the gingival epithelium covering the lesion showed marked extension into the lesion, and direct continuity between the extended rete pegs and tumor follicles was evident. Ultrastructural examination showed that the rete pegs gradually became transformed into double-stranded epithelial cords as they elongated deeply, and that the ends of these epithelial cords gradually became transformed into tumor follicles. These findings suggest that the potential for differentiation is maintained in the basal cells of the gingival epithelium throughout life, and can be triggered by unknown stimuli. The ultrastructure of the tumor follicles was similar to that of intraosseous follicular ameloblastoma, but was different from that of cutaneous basal cell carcinoma. Histochemical staining for keratin protein revealed that the central cells of tumor follicles and the covering epithelium were positive, whereas the peripheral cells of tumor follicles and the elongated rete pegs were negative.

Aged↗
PubMed1988

[Prognostic factors in genitourinary cancer].

Prognostic factors in genitourinary cancers, renal cell carcinoma, bladder cancer, prostatic cancer, and testicular tumor, were discussed from several aspects on the basis of the analysis of own cases and reviews of literatures. The anatomical distribution of disease, particularly beyond the kidney, and degree of tumor differentiation were mostly related to prognosis in renal cell carcinoma. In bladder cancer, macroscopic growth pattern, histopathological intramural mode of spread, lymphatic and venous invasion, played an important role in prognosis, as do tumor grade and stage including metastasis. Hormone dependency and tumor markers were reconfirmed to be important and complementary as prognostic indicators as well as stage and grade in prostatic cancer. In testicular tumors, the most important factors for survival were extent of disease and tumor size, and histological cell type and determination of tumor markers, AFP and HCG, were also important and complementary as prognostic indicators.

Age Factors↗
PubMed1987

Regulation of insulin-stimulated glucose transport in the isolated rat adipocyte. cAMP-independent effects of lipolytic and antilipolytic agents.

This paper examines the modulation of insulin-stimulated glucose transport activity in rat adipose cells by ligands for receptors (R) that mediate stimulation (Rs; lipolytic) or inhibition (Ri; antilipolytic) of adenylate cyclase. The changes in glucose transport activity and cAMP, as assessed by 3-O-methylglucose uptake and (-/+) cAMP-dependent protein kinase (A-kinase) activity ratios, respectively, were monitored under conditions that maintain steady-state A-kinase activity ratios (Honnor, R. C., Dhillon, G. S., and Londos, C. (1985) J. Biol. Chem. 260, 15122-15129). Removal of endogenous adenosine with adenosine deaminase decreased insulin-stimulated glucose transport activity by approximately 30%, which was prevented or restored with Ri agonists such as phenylisopropyladenosine, nicotinic acid, and prostaglandin E1. These changes in transport activity were not accompanied by changes in A-kinase activity ratios, indicating that Ri-mediated effects on transport are independent of cAMP changes. Addition of an Rs ligand, isoproterenol, in the presence of adenosine increased kinase activity but did not change glucose transport activity. Conversely, upon removal of adenosine, addition of Rs ligands such as isoproterenol, adrenocorticotropic hormone, or glucagon strongly inhibited transport (approximately 50%) and stimulated kinase activity. However, subsequent addition of phenylisopropyladenosine nearly restored transport activity without alteration of A-kinase activity. These data and additional kinetic experiments suggest that Rs-mediated glucose transport modulations are also independent of cAMP. The interchangeability of ligands for both Rs and Ri receptors in modulating transport activity suggests that these cAMP-independent effects are mediated by the stimulatory (Ns) and inhibitory (Ni) guanyl nucleotide-binding regulatory proteins of adenylate cyclase. All Rs-and Ri-induced changes in transport activity occurred without a change in glucose transporter distribution, as assessed by D-glucose-inhibitable cytochalasin B binding, suggesting that Rs and Ri ligands modulate the intrinsic activity of the glucose transporter present in the plasma membrane.

3-O-Methylglucose↗
PubMed1987

Postoperative systemic adjuvant chemotherapy for bladder cancer.

Forty-six patients with bladder cancer without distant metastasis (M0) were treated by chemotherapy as an adjuvant after total cystectomy using three protocols (protocol I: adriamycin 50 mg/m2, cyclophosphamide 500 mg/m2, and cis-platinum 50 mg/m2 i.v., starting at least 2 weeks after surgery every 3 weeks for three cycles; protocol II: adriamycin 30 mg/m2 on the 1st postoperative day, cyclophosphamide 300 mg/m2 on the 1st and the 7th days; protocol III: FT-207 60 mg/m2, p.o. every day for 1 year). Average follow-up periods after surgery by protocol were 18 months for protocol I, 31 for protocol II, and 43 for protocol III. Analysis of the survival curves showed no statistically significant differences among the three groups or between a historical control group of 106 patients and the entire patient population examined in the present study. The histopathological grades recorded in the 46 patients were G1, G2, and G3 in 1, 22, and 23, respectively. However, from a study of 48 pT3 and pT4 cases, the survival rate of 10 patients receiving protocol I therapy was statistically significantly higher than those of 12 patients treated according to protocol II and of 26 historical controls, at 1 year and 2 years, respectively. Toxic effects, with gastrointestinal symptoms including nausea and vomiting and myelosuppression (including leukopenia and anemia) were more frequent with protocol I. Alopecia occurred in about 80%-90% of patients treated according to either protocol I or II. Almost all patients could tolerate adjuvant chemotherapy, and none of them died as a result of these regimens. The results recorded in this study justify the evaluation of combination adjuvant chemotherapy with adriamycin, cyclophosphamide and cis-platinum in a prospectively randomized trial.

Adult↗
PubMed1987

Immunosuppressive acidic protein in patients with testicular cancer.

Serum immunosuppressive acidic protein was compared to lactic dehydrogenase as a marker for testicular cancer in 54 patients with testicular cancer, 62 with benign urological diseases and 203 healthy controls. The mean value of serum immunosuppressive acidic protein in patients with testicular cancer (598 +/- 293 micrograms. per ml.) was statistically higher than that in patients with benign disease (429 +/- 163 micrograms. per ml.) and healthy controls (368 +/- 73 micrograms. per ml.). There were statistically significant differences in serum immunosuppressive acidic protein levels between controls and patients with stage 2 (p less than 0.0001) or stage 3 (p less than 0.001) testicular cancer, and between those with stage 1 and stage 2 (p less than 0.0001) or stage 3 (p less than 0.001) disease, respectively. The usefulness of immunosuppressive acidic protein as a marker for testicular cancer also was compared to that of lactic dehydrogenase. Immunosuppressive acidic protein and lactic dehydrogenase levels were elevated almost equally in patients with stage 2 or 3 disease (range 71 to 92 per cent). However, immunosuppressive acidic protein levels were elevated in only 3 of 25 patients with stage 1 cancer (12 per cent), compared to 11 of 25 (44 per cent) with elevated lactic dehydrogenase levels. Immunosuppressive acidic protein was correlated better with tumor stage. In conclusion, serum immunosuppressive acidic protein determinations may be useful in patients with testicular cancer for staging, monitoring treatment results and predicting recurrence.

Adult↗
PubMed1987

Melanin-pigment in complex odontoma.

A case of complex odontoma, which contained melanin-pigment in the odontogenic epithelial cells in a 19-year-old Japanese male is reported. In addition to the characteristic histopathologic features of complex odontoma, odontogenic epithelial cells containing melanin-pigment were widely distributed in the fibrous connective tissue stroma which differed from that of the dental papilla in cellular appearance. No dendritic cells containing melanin-pigment were found in any sections. The possible histogenesis of melanin-pigment in the odontogenic epithelial cells was discussed, though no conclusion could be drawn from the present observation as to its origin in complex odontoma.

Adult↗
PubMed1987

Failure of root development of human permanent teeth following irradiation.

Complete absence of root formation of the upper incisors, canine and first premolar was reported in a 27-year-old female who had received radiation therapy for a retinal glioma of the right eye at age of 3 years 1 month. Ground and decalcified sections showed no remarkable changes in enamel and dentin of the crowns, but the pulp floor was closed by irregular dentin deposit despite the absence of root formation. The outer surface of the irregular dentin was covered by acellular cementum, and the periodontal membrane was undeveloped. A slight degree of fibrosis was seen in the pulp, but the coronal part of the dentin was lined by odontoblasts. The theory that tooth eruption is caused by the growth of the root is not substantiated by the observation in this case.

Abnormalities, Radiation-Induced↗
PubMed1987

Cytoskeleton in vitro: preparation of isolated cytoskeletons with three-dimensional architecture.

Cytoskeletons with three-dimensional architecture were isolated from cultured normal rat kidney cells. The preparation procedure consisted of Triton-demembranization of suspended cells followed by differential and sucrose density gradient centrifugation. By using higher (0.5%) and lower (0.1%) Triton concentrations for demembranization, two kinds of isolated cytoskeletons (CSK), called H-CSK and L-CSK, respectively, were prepared. H-CSK and L-CSK displayed unique morphology and protein composition. Three classes of cytoskeletal filaments, microfilaments, intermediate filaments, and microtubules were shown to be major components in the electron microscopic images of the H-CSK. Stereoscopic electron microscopy of the H-CSK, dried by the critical point method, revealed that the cytoskeletal filaments are arranged in three-dimensional configurations even after isolation in vitro. Two-dimensional gel electrophoresis demonstrated that the H-CSK was composed mainly of actin, tubulin, and vimentin, reflecting its basic architecture. Electron microscopic images of L-CSK were more intricate than images of the H-CSK and showed, in addition to the filament types discussed above, anastomosing networks of short filamentous structures. These short filaments, with diameters of 3-8 nm and lengths of 30-150 nm, seemed to cross-link other elements of the cytoskeleton. The morphology of these short filaments resembles that of microtrabeculae observed in situ. Two-dimensional gels of the L-CSK showed over 100 protein spots when the gels were stained by the silver method. Subsequent treatment of the L-CSK with 0.5% Triton removed the microtrabeculae-like materials leaving as a residue the basic cytoskeleton similar to the H-CSK. Our observations indicate that microtrabeculae are composed of heterogenous proteins associated, in some instances, with a core structure of actin.

Animals↗
PubMed1987

Massive osteolysis of the mandible.

This report deals with a massive osteolysis, which is a rare disease characterized by the progressive dissolution of contiguous osseous structure, occurring in the mandible of a 46-year-old Japanese female. Histopathologic examination of the amputation material revealed that the mandibular body, ramus, condylar and coronoid processes were completely replaced by fibrous tissue, but inferior alveolar nerve and artery in the lesion were intact. A few small islands of osteoid tissue or immature fibrous bone were seen in the lesion. In the transitional area between the lesion and normal bone, active absorption of bone trabeculae was in progress and intertrabecular spaces were occupied by densely packed fibroblastic cells, however, angiomatous proliferation of vessels was not observed. A few bone trabeculae were surrounded by osteoclasts, but osteoclasts might not play a primary etiological role in massive osteolysis.

Female↗