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Biomedical subjects

A Yamada

Publications and source records attributed to A Yamada.

At least 361 records · Page 20Linked to original sources
PubMed1994

Expression of transforming growth factor-beta 1 and its relation to endomysial fibrosis in progressive muscular dystrophy.

Progressive muscular dystrophy is characterized by muscle fiber necrosis, regeneration, and endomysial fibrosis. Although absence of dystrophin has been known as the cause of muscle fiber degeneration, pathogenesis of interstitial fibrosis is still unknown. Transforming growth factor-beta 1 (TGF-beta 1) induces accumulation of extracellular matrix in various diseases, such as liver cirrhosis and interstitial pneumonitis. To investigate its function on the pathogenesis of progressive muscular dystrophy, it was necessary to determine the degree of TGF-beta 1 expression and the site of TGF-beta 1 immunoreactivity. In Duchenne muscular dystrophy and most of Becker muscular dystrophy, high TGF-beta 1 immunoreactivity expressed on muscle fibers and extracellular space. In other myopathies with endomysial fibrosis, however, TGF-beta 1 was seldom observed. We also examined the immunoreactivity of the latent TGF-beta binding protein, which is bound to the TGF-beta precursors. In all Duchenne muscular dystrophy and half of Becker muscular dystrophy cases, high latent TGF-beta 1 binding protein immunoreactivity was seen, but in other myopathies its immunoreactivity was seldom seen on muscle fibers or extracellular space. Therefore TGF-beta 1 may play an important role in synthesis and accumulation of extracellular matrix in progressive muscular dystrophy.

Animals↗
PubMed1993

Tissue-specific distribution and age-dependent increase of human CD11b+ T cells.

Distribution of CD11b Ag, a member of the leukocyte integrin (beta 2 integrin) family, on human T cells is not well characterized. We investigated in this study the tissue distribution and age-related alteration of human CD11b+ T cells. Significant proportions of CD11b+ cells were found in T cells from adult peripheral blood (18-58 yr) (20%), liver (32%), and spleen (16%), but were rarely observed in those from thymus, lymph nodes, intraepithelial lymphocytes, lamina propria lymphocytes, and lung. In contrast, percentages of CD28+ T cells, a counter population of CD11b+ T cells, were highest in lymph nodes (91%), modest in intraepithelial lymphocytes (82%), lamina propria lymphocytes (77%), PBL (77%), spleen (73%) and lower in thymus (62%), lung (60%) and liver (56%). The CD11b+ T cells from peripheral blood gradually increased with age, whereas the CD28+ T cells showed an age-dependent decrease. Namely, the percentages of CD11b+ T cells were 6% in newborns (cord blood), 15% in young adults (18 to 22 yr), 25% in middleaged adults (45 to 58 yr), and 27% in aged adults (72 to 86 yr), whereas those of CD28+ T cells were 96%, 83%, 72%, and 71%, respectively. Proportions of CD11b+ T cells in TCR-gamma delta+ or CD8+ T cells were, respectively, higher than those in TCR-alpha beta+ or CD4+ T cells. Age-dependent increase of CD11b+ T cells in CD8+ T cells was more obvious than that of CD4+ T cells. Furthermore, CD11b+ CD28+ T cells increased in the peripheral blood only of aged adults. The percentage of CD11b+ CD28+ T cells in TCR-gamma delta+ T cells was highest in young adults (25%), whereas that in CD4+ T cells was highest in aged adults (15%). CD11b+ CD28+ T cells expressed much potent IFN-gamma, IL-2, and IL-4 at mRNA level than CD28+ CD11b- T cells or CD11b+ CD28- T cells, and had potential cytotoxic activity. Roles of CD11b+ T cells in vivo were discussed.

Adolescent↗
PubMed1993

Evidence of impaired endothelium-dependent coronary vasodilatation in patients with angina pectoris and normal coronary angiograms.

BACKGROUND: A group of patients has been described who have chest pain resembling angina and positive exercise tests, but normal coronary angiograms and no coronary-artery spasm. This constellation of features has sometimes been called syndrome X or microvascular angina. We attempted to determine whether endothelium-dependent vasodilatation of the coronary vasculature was impaired in patients with this syndrome. METHODS: We infused the endothelium-dependent vasodilator acetylcholine and the endothelium-independent vasodilators papaverine and isosorbide dinitrate into the left coronary artery of 9 patients and 10 control subjects. The diameter of the left anterior descending coronary artery was assessed by quantitative angiography, and changes in coronary blood flow were estimated with the use of an intracoronary Doppler catheter. RESULTS: Acetylcholine, given in doses of 1, 3, 10, and 30 micrograms per minute, increased coronary blood flow in a dose-dependent manner in both groups. However, the mean (+/- SD) acetylcholine-induced increases in coronary blood flow were significantly less (P < 0.001) in the patient (8 +/- 14, 37 +/- 37, 59 +/- 67, and 103 +/- 77 percent, respectively) than in the controls (62 +/- 52, 186 +/- 93, 341 +/- 128, and 345 +/- 78 percent, respectively). The changes in coronary blood flow in response to 2 mg of isosorbide dinitrate (236 +/- 66 percent vs. 280 +/- 56 percent) and 10 mg of papaverine (366 +/- 168 percent vs. 411 +/- 92 percent) did not differ significantly between the patients and controls. The administration of papaverine resulted in myocardial lactate production in the patients but not in the controls. The three lower doses of acetylcholine caused a similar degree of dilatation of the left anterior descending coronary artery in the two groups, and the highest dose caused a similar degree of constriction in the two groups. Isosorbide dinitrate and papaverine caused a similar degree of dilatation in both groups. CONCLUSIONS: These findings suggest that endothelium-dependent dilatation of the resistance coronary arteries is defective in patients with anginal chest pain and normal coronary arteries, which may contribute to the altered regulation of myocardial perfusion in these patients.

Acetylcholine↗
PubMed1993

Age-dependent survival-promoting activity of vitamin K on cultured CNS neurons.

Neurons from the central nervous system (CNS) of rat embryos die within several days when seeded at a low density of 10(4) cells/cm2 and cultured in a serum-free defined medium. Using these culture systems, we searched for agents to promote the survival of these neurons. As a consequence, a fat-soluble vitamin, vitamin K1, was found to possess such kind of activity: more than 50% of the cortical neurons from 19-day-old rat embryos could survive for 4 days in the presence of vitamin K1, whereas almost all neurons died in its absence. The survival-promoting effect of vitamin K1 was found on neurons from not only cortex, but also hippocampus, striatum, and septum. In addition to vitamin K1, vitamin K2 and K3 also showed the same effect on cortical neurons. The effect of vitamins K1 and K2 was observed at concentrations from 10(-8) to 10(-6) M, and that of vitamin K3 was slightly detected at 10(-6) M. Furthermore, we examined the effect on the neurons from 16- and 21-day-old embryos, too. The activity of vitamin K1 was weaker toward the neurons from 21-day-old embryos compared with that toward 19-day-old ones, and was not recognized toward 16-day-old ones. These results suggest the potential role of the K vitamins on the maintenance of the survival of CNS neurons during the later stages of embryogenesis in vivo.

Animals↗
PubMed1993

Induction of topoisomerase I-mediated DNA cleavage by a new indolocarbazole, ED-110.

ED-110 is a new semisynthetic antitumor agent derived from a novel indolocarbazole antibiotic, BE-13793C, produced by an actinomycete. ED-110 induced topoisomerase I-mediated DNA cleavage in vitro as strongly as camptothecin, whereas topoisomerase II-mediated DNA cleavage was not induced by this agent. Exposure of P388 cells to ED-110 caused a typical topoisomerase toxicity, i.e.: formation of cleavable complexes; inhibition of nucleotide synthesis rather than protein synthesis; and cell cycle arrest in G2. ED-110 inhibited the growth of P388 cells, with a 50% growth-inhibitory concentration of 44 nM. ED-110 is distinguished from camptothecin by its very different structure and its ability to intercalate into double-stranded DNA. These results suggest that ED-110 has potential as a novel antitumor agent targeting topoisomerase I.

Animals↗
PubMed1993

A novel antigen (H47 Ag) on human lymphocytes involved in T cell activation.

Surface molecules involved in human T cell activation were investigated using a newly developed monoclonal antibody (H47 mAb). H47 antigen (Ag) recognized by H47 mAb was expressed on approximately 10% of resting T cells (mostly CD4-CD8+), 30% of phorbol 12-myristate 13-acetate (PMA)-activated T cells (both CD4+CD8- and CD4-CD8+), and most NK, B cells, and monocytes in the peripheral blood mononuclear cells (PBMC). H47 mAb respectively immunoprecipitated a 100 or 120-kD molecular weight (MW) membrane protein of T cells and monocytes under nonreducing or reducing conditions, suggesting that H47 Ag consists of a single polypeptide that has intramolecular disulfide bonds. H47 mAb significantly enhanced PMA-induced proliferation of PBMC in a monocyte-independent fashion. H47 mAb, however, failed to enhance T cell proliferation induced by anti-CD3 mAb, anti-CD2 mAb, or phytohemagglutinin (PHA). H47 mAb also enhanced PMA-induced interleukin-2 receptor (IL-2R) expression and IL-2 synthesis, but did not induce a change in intracellular free calcium ([Ca2+]i) of T cells. These results suggest that H47 Ag is a new membrane molecule involved in PMA-induced T cell activation.

Animals↗
PubMed1993

Interrelationship between autoepitope, DNA-binding domain, and CRP-binding domain on a histone H1 molecule.

The interrelationship between autoepitopes, DNA-binding domains, and C-reactive protein (CRP)-binding domains on a histone H1 molecule was examined using fusion proteins of beta-galactosidase and truncated histone H1 molecules. At least two CRP-binding sites were detected on a histone H1 molecule. Site 1 was composed of approximately 25 amino acids and calcium ion was required for the binding of CRP. Site 2, composed of approximately 20 amino acids and not requiring calcium ion, was identical or located very close to a DNA-binding domain and an epitope of anti-histone H1 autoantibodies in SLE sera. These data suggest that, at physiological ionic strength, histone H1 of either free or immune-complexed form could bind to CRP via site 1. These data are discussed with respect to the possible role of CRP in the handling and clearance of immune complexes in patients with systemic lupus erythematosus.

Autoantigens↗
PubMed1993

Development of postmolar trophoblastic disease after partial molar pregnancy.

We investigated the clinical characteristics of patients with partial molar pregnancy and patients who developed invasive partial mole. Between 1981 and 1990, 349 patients were followed up by the Aichi prefecture trophoblastic disease registration center after partial molar pregnancy. Ten of the 349 patients with partial molar pregnancy developed invasive partial mole, an incidence (2.87%) significantly lower (P < 0.01) than that for the development of invasive complete mole (174/1410, 12.34%) following complete molar pregnancy during the same period. None of the patients had any histologic evidence of choriocarcinoma after partial molar pregnancy. The medical records of these 10 patients were compared with those of 85 of 174 registered patients with invasive complete mole, whose clinical information could be used. The interval from molar delivery to the diagnosis of invasive mole was under 9 weeks (mean, 4.90 weeks) for the patients with invasive partial mole and was significantly shorter than that for the patients with invasive complete mole, from 2 to 18 weeks (mean, 8.12 weeks) (P < 0.01). All 10 patients with invasive partial mole achieved a negative hCG level (< 0.5 mIU/ml) with eight courses or less of chemotherapy (mean, 5.50 courses). The number of courses was the same as that in the invasive complete mole group (mean, 5.70 courses). None of the patients with invasive partial mole developed recurrence. We conclude that all patients with partial molar pregnancy should be followed up as are those with complete molar pregnancy. Some patients with partial molar pregnancy will develop invasive partial mole with a relatively short interval, but remission can be achieved without the recurrence and choriocarcinoma seldom develops after partial molar pregnancy.

Adult↗
PubMed1993

In vitro transcription and replication of the mumps virus genome.

By the use of lysolecithin-permealized extracts from mumps virus-infected HeLa cells, we have developed an in vitro system, which not only directed the synthesis of mumps virus mRNAs but also supported replication of the genomic RNA. Furthermore, upon transcription of the P gene, both faithful and edited copies of the P gene were detected by RNase mapping with a riboprobe. Thus this system seems to promote biochemical analyses of underlying mechanisms operative in mumps virus gene expression and replication, including RNA editing.

Cell-Free System↗
PubMed1993

Reconstruction of the cervical trachea with a free forearm flap.

With the aim of voice restoration after repair of a total defect or obstruction of the cervical trachea, we developed a new method of total cervical tracheal reconstruction with a free forearm flap. The forearm flap is inverted to form a tube and then interposed between the subglottic trachea and an adjacent cutaneous fistula created at the upper portion of the tracheostoma. A permanent tracheostoma is preserved, and an L-shaped silicone tube is inserted in the reconstructed cervical trachea and the tracheostoma as a stent. In two patients, both became able to speak.

Adolescent↗
PubMed1993

Rapid detection of mumps virus by the polymerase chain reaction.

A procedure for detecting mumps virus in under 48 h was developed using the PCR. The sensitivity of the PCR amplification reaction and of the detection of the PCR product was significantly improved by: (i) enriching for viral template RNAs by overnight culture of the virus in Vero cells and (ii) substitution of polyacrylamide gel analysis for agarose gel electrophoresis. The technique was capable of detecting 1-20 infectious units of virus or an equivalent of 1-10 pg of mumps virus-specific plasmid DNA.

Animals↗
PubMed1993

Differentiation of mumps vaccine strains from wild viruses by single-strand conformation polymorphism of the P gene.

The DNA fragments amplified through the polymerase chain reaction from part of the P gene of four mumps vaccine strains (Urabe, Torii, Hoshino and Miyahara) were subjected to single-strand conformation polymorphism (SSCP) analysis. These four vaccine strains were differentiated from each other. Furthermore, twelve wild viruses and a laboratory strain (Enders strain) were also distinguished by this method. Viruses isolated from patients who developed aseptic meningitis 4 to 6 weeks after measles-mumps-rubella vaccination showed identical SSCP patterns with the vaccine strain used for immunization. These results were well correlated with sequence analysis of P-gene segments, indicating high applicability of the SSCP analysis for differentiation of mumps vaccine strains not only from each other but from wild viruses.

DNA, Single-Stranded↗
PubMed1993

Movement of actin away from the center of reconstituted rabbit myosin filament is slower than in the opposite direction.

By decreasing ionic strength slowly, thick filaments of several micrometers in length were obtained from purified rabbit skeletal muscle myosin. Dark-field observation showed these filaments with their center scattering light extensively. Active movement of actin filaments complexed with tetramethyl rhodamine-phalloidin along the reconstituted myosin filaments was observed. Actin filaments moved towards the center of myosin filaments at a speed of 3.9 +/- 1.6 microns s-1 (mean +/- SD, n = 40) and often continued to move beyond the center towards the tip of the opposite side at a lower speed. The speed of the movement away from the center was 1.0 +/- 0.6 microns s-1 (n = 59). Thus, the functional bipolarity in terms of the movement speed which was first found in native thick filaments of molluscan smooth muscle is also seen in reconstituted filaments from purified rabbit skeletal muscle myosin. The difference of the speed between the two directions is considered to be due to properties of myosin molecules themselves.

Actins↗
PubMed1993

Experimental study of prefabricated flaps using vein grafts.

Prefabrication of a flap may represent a new alternative, not limited by natural vascular territories, for creating donor sites. Experimental procedures in which an A-V shunt results in sufficient flap neovascularization have been reported. This study was undertaken to investigate how neovascularization from the recipient bed affects survival of this type of flap. An 8-cm x 10-cm prefabricated skin flap, nourished by the left epigastric vein, was constructed in a rabbit abdomen. In half the models, a silicone sheet was placed under the flap, to impede neovascularization from the bed. The flaps of both experimental groups showed excellent viability, and no statistically significant difference in survival rate was recognized. This flap was found to be independent of the vascularity of the underlying bed.

Abdomen↗
PubMed1993

Pseudocyst of the auricle: case reports and its biochemical characteristics.

Pseudocyst of the auricle is a rare, asymptomatic cystic swelling of the auricle resulting from accumulation of yellow viscous fluid with unknown cause. We herein report 3 such patients in whom biochemical study of the aspirated fluid revealed markedly elevated activity of lactate dehydrogenase (LDH) and a preponderance of LDH-4 and LDH-5. We postulate that pseudocyst formation is due to the disruption of the auricular cartilage and that LDH in the fluid is released from the auricular cartilage. This observation supports that the lesions represent a pattern of chondromalacia. It is hypothesized that the cause of such pseudocysts is repeated minor trauma.

Adult↗
PubMed1993

Extremely thinned inferior rectus abdominis free flap.

To overcome a major drawback of the inferior rectus abdominis free flap, unpleasant thickness in a obese patient, a method of extreme thinning of the flap has been introduced. Extreme thinning is achieved by resecting a large volume of subcutaneous fatty tissue of the flap using scissors without damaging the subdermal vascular plexus. According to our clinical experience, it is supposed that the extremely thinned portion can be prepared safely when the width-to-length ratio is within 1:2.

Abdominal Muscles↗
PubMed1993

Eye socket reconstruction with free-flap transfer.

Patients afflicted with retinoblastoma or other malignant orbital tumors often undergo eyeball excision and irradiation in infancy, which results in severe deformities of the orbit. It is very difficult to achieve the reconstruction of such severely depressed and contracted eye sockets because both augmentation and formation of an eye socket are required. We usually perform a free-flap transfer with microvascular anastomoses in such situations and have experienced 25 cases since 1980. Various kinds of flaps, such as the groin flap, dorsalis pedis flap, scapular flap, and others, were utilized. The degree of depression and whether sufficient conjunctiva for lining of the eye socket remains are important in the selection and design of the donor flap. To obtain an orbit with a natural appearance, many of the patients required subsequent minor revision operations such as debulking, dermal fat grafts, canthoplasty, fascia suspension, and so on.

Adolescent↗