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Biomedical subjects

H Miwa

Publications and source records attributed to H Miwa.

At least 199 records · Page 11Linked to original sources
PubMed1994

An integrated approach to the design and engineering of hybrid arterial prostheses.

PURPOSE: A newly devised hybrid small-caliber graft was developed. The graft consisted of three components: a microporous polyurethane graft (inside diameter 3 mm; length 5 cm) with compliance close to that of a natural artery; an artificial basement membrane composed of a complex gel of type I collagen and dermatan sulfate, which showed enhanced adhesion and growth of endothelial cells (ECs) and reduced adhesion of platelets in vitro; and an autogenous EC monolayer with high degrees of cell-substrate and cell-cell interactions, which was performed before implantation. METHODS: Twenty EC-seeded grafts were implanted bilaterally into carotid arteries of dogs without anticoagulant. The implantation period was up to 26 weeks. RESULTS: The overall patency rate for seeded grafts was 75%. The percentage of endothelial coverage of seeded grafts was 98% as implanted, 92% at 2 weeks, and 100% after 12 weeks. The mean intimal thickness of grafts was around 80 microns at 12 weeks. Little additional increase was observed at 26 weeks. CONCLUSIONS: It appears that the complete endothelialization as implanted, high cell-to-substrate adhesive strength that resists hydrodynamic shear stress, and biomechanical compatibility of the polyurethane graft functioned cooperatively to provide a vascular graft with high antithrombogenicity and minimal hyperplasia. The integrated approach of combining biomechanical and cellular engineering designs leading to an important functional smaller-caliber graft is discussed.

Animals↗
PubMed1994

S100-positive histiocytes in T-cell-dependent area in human lymph nodes express P-glycoprotein.

In the present study, we examined P-glycoprotein (P-gp)-expressing cells in human lymph nodes (LN) from patients with reactive lymph adenitis and various malignant lymphomas (ML). MDR1 mRNA was detected in all reactive LN and in 8 of 10 ML samples examined by reverse transcription polymerase chain reaction (RT-PCR). The signal intensity of the bands was stronger in samples from T-cell ML LN than in those from LN of reactive lymph adenitis and B-cell ML. Immunohistochemistry also showed positive reactivity with cellular components in the LN. The P-gp-positive cells, detected by UIC2, in reactive lymph adenitis and ML samples were large in size in the T-cell-dependent paracortical area in LN. Further, morphological characteristics were similar in UIC2-positive cells between reactive and ML LN. Double staining with UIC2 and a hematopoietic cell lineage-specific monoclonal antibody showed that UIC2-positive cell co-expressed S-100, but not other lymphocyte- and ML cell-specific antigens, indicating that these cells correspond to histiocytes in the T-cell-dependent paracortical area. Our results show that P-gp was expressed in histiocytes but not ML cells in LN, and suggest that this molecule may play an important role in the biological function of histiocytes and/or for maintenance of homeostatic levels in T-cell ML LN.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Poor response to intensive chemotherapy in de novo acute myeloid leukaemia with trilineage myelodysplasia. Japan Adult Leukaemia Study Group (JALSG).

The findings of morphologically dysplastic features in haemopoietic cells in de novo acute myeloid leukaemia (AML) has been named AML with trilineage myelodysplasia (AML/TMDS). We analysed the clinical data, karyotypes, and treatment outcomes of 230 de novo AML patients treated with the Japan Adult Leukaemia Study Group AML-87 protocol. 40 (17%) patients had AML/TMDS. Platelet count was significantly higher (P = 0.006) and bone marrow blasts were fewer (P = 0.01) in the AML/TMDS group than in the AML without TMDS. Abnormal karyotype was shown in 12/30 patients (40%) analysed. The complete remission (CR) rate for AML/TMDS was significantly lower than AML without TMDS (63% v 81%) (P = 0.01). The overall survival curves showed that the 40 patients with TMDS had a significantly worse survival than the 190 without TMDS (P = 0.0005). AML/TMDS also showed significantly worse disease-free survival (DFS) (P = 0.0001). Multivariate analysis revealed that the absence of TMDS in AML was the most significant factor in obtaining CR (P = 0.01) and a significant factor in predicting longer DFS (P = 0.04). Our data suggest that AML/TMDS responds poorly to intensive chemotherapy. Further study is required to determine the best treatment strategy for AML/TMDS and the biological differences between AML/TMDS and other types of AML.

Adult↗
PubMed1994

PRAD1 gene over-expression in mantle-cell lymphoma but not in other low-grade B-cell lymphomas, including extranodal lymphoma.

Employing Northern blot analysis and the polymerase chain reaction, we investigated PRAD1 gene overexpression in the tumour tissues of 58 patients with B-cell lymphoma. These findings were then examined in relation to the patients' clinical and immunohistological characteristics. The over-expression of this gene was detected in 6/8 patients with mantle cell lymphoma (MCL) and in only 1/50 other lymphomas, indicating its close association with MCL. The patients with MCL had common clinical findings of advanced disease with generalized lymphadenopathy on admission, and they had a CD5+CD10-IgD+ phenotype. The patients with chronic lymphocytic leukaemia (CLL) also showed findings indicating a distinctive disease entity: a CD5+CD10-IgD+ phenotype and lack of PRAD1 over-expression. In contrast, most patients with diffuse low-grade lymphoma other than MCL and CLL had localized extranodal disease, expressed a CD5-CD10-IgD- phenotype, and lacked PRAD1 over-expression. These findings suggest that extranodal low-grade lymphomas differ from nodal MCL and are not part of the spectrum of CLL.

Base Sequence↗
PubMed1994

Usefulness of the pulmonary vein flow velocity-time profile as an estimate of left atrial storage fraction.

During ventricular systole, the left atrium (LA) stores a certain amount of ventricular stroke volume; this is defined as an LA storage volume. From cineangiocardiograms, an LA storage fraction is obtained as the ratio of the LA storage volume to left ventricular stroke volume. From the pulmonary vein (PV) flow velocity-time profile, the LA storage fraction may be estimated as a ratio of the PV flow velocity-time integral during systole (Sa) to a sum of that during systole and diastole (Sa+Da), namely, Sa/(Sa+Da), provided that the PV cross-sectional area remains relatively unchanged during one cardiac cycle and that the PV flow velocity-time profile is similar in any of the PVs draining to the LA. To evaluate usefulness of Doppler echocardiographic method of estimating the LA storage fraction, the authors measured the LA storage fraction from the left upper PV flow velocity-time profile by transesophageal Doppler echocardiography and compared it with the LA storage fraction from conventional cineangiocardiographic volumes. Subjects were 23 patients with a variety of cardiac diseases in normal sinus rhythm, ranging from eighteen to seventy-four years of age. The LA storage fraction was 0.58 +/- 0.12 (mean +/- SD) from cineangiocardiography and 0.64 +/- 0.08 from Doppler echocardiography larger than that from cineangiocardiography (P < 0.01), the correlation was good (r = 0.643). The authors conclude that the left upper PV flow velocity-time profile appears to provide a better correlation with that by cineangiography and may be used as a reliable quantitative estimate of the LA storage fraction.

Adult↗
PubMed1994

A study on left atrial transport function. Effect of age or left ventricular ejection fraction on left atrial storage fraction.

Left atrial (LA) storage fraction is defined as the ratio of storage volume of the left atrium (LA) during ventricular systole to left ventricular (LV) stroke volume. To test their hypothesis that left atrial (LA) storage fraction is increased to compensate for impaired LV filling in the heart of aged subjects or with impaired LV ejection fraction, the authors studied 33 "normal" subjects and 25 patients with coronary artery disease. LA volume was measured by LA cineangiocardiography, and LV stroke volume and LV ejection fraction were measured by LV cineangiocardiography. To further evaluate the determinants of changes in LA storage fraction, they measured the ratio of LA active release volume to LV stroke volume, and the ratio of LA passive release volume to LV stroke volume. In "normal" subjects, LA storage fraction was increased with age (r = 0.584, P < 0.01). In patients with coronary artery disease, LA storage fraction was increased as LV ejection fraction was decreased (r = -0.525, P < 0.01). In both cases, LA active release fraction was significantly associated with changes in LA storage fraction rather than in LA passive release fraction. They conclude that LA storage fraction may be an important determinant of LV filling mainly through the LA active release fraction.

Adolescent↗
PubMed1994

Successful continuous treatment with all-trans retinoic acid for acute promyelocytic leukemia; secondary malignancy after the treatment of osteosarcoma.

We report a rare case of complete remission for 32 months with continuous treatment with all-trans retinoic acid (ATRA) alone in a patient with acute promyelocytic leukemia which developed as a second malignancy after the treatment of osteosarcoma after failure of conventional chemotherapy. The adverse effects of ATRA were apparently tolerable.

Adolescent↗
PubMed1994

Synthesis and structure-activity relationships of 7 beta-[(Z)-2-(2- aminothiazol-4-yl)-3-(substituted)-2-propenoylamino]-3-cephems with C-3 substitutions.

Synthesis and biological activity of a series of 7 beta-[(Z)-2-(2- aminothiazol-4-yl)-3-(substituted)-2-propenoylamino]-3-cephe m-4-carboxylic acids with C-3 substitutions and their pivaloyloxymethyl esters are described. These acid compounds exhibited potent antibacterial activity against both Gram-positive and Gram-negative bacteria. Pivaloyloxymethyl esters of selected compounds in this series were found to be well absorbed from small intestine in mice. Pivaloyloxymethyl 7 beta-[(Z)-2-(2-aminothiazol-4-yl)-2-pentenoylamino]-3- carbamoyloxymethyl-3-cephem-4-carboxylase hydrochloride hydrate (S-1108) was finally selected as the candidate for clinical evaluation.

Administration, Oral↗
PubMed1993

Expression of MDR1 gene in acute leukemia cells: association with CD7+ acute myeloblastic leukemia/acute lymphoblastic leukemia.

MDR1 gene expression was examined in acute leukemia cells from 75 Japanese patients at diagnosis (50 with acute myeloblastic leukemia [AML]: 10 M1, 18 M2, 5 M3, 8 M4, 9 M5; 25 with acute lymphoblastic leukemia [ALL]: 13 B-precursor, 12 T-lineage). The results of MDR1 mRNA expression by reverse transcriptase polymerase chain reaction were confirmed by immunostaining using the anti-P-glycoprotein monoclonal antibody UIC2 and by a functional study using the rhodamine efflux test. Morphologically, AML M1 cases had the highest incidence of MDR1 gene expression (6 of 10 patients). Phenotypically, CD7 and CD34 were the only surface markers that were significantly associated with MDR1 gene expression (P < .01). In CD7+CD4-CD8- ALL, which is thought to originate from the lymphohematopoietic stem cell, expressed the MDR1 gene with a high incidence (six of eight patients), whereas three surface CD3+ and one CD4+CD8+ T-cell ALL (T-ALL) did not have detectable MDR1 transcripts. Only two cases of 13 B-precursor ALL had MDR1 mRNA, one of which had the Philadelphia (Ph1) chromosome. No association was observed between MDR1 gene expression and CD34 positivity in ALL. Our results that MDR1 mRNA was frequently expressed in CD7+ AML and CD7+CD4-CD8- ALL, together with the previous reports indicating clinical similarities between these leukemias, provides a clue to clarify a relationship between CD7+ AML and CD7+CD4-CD8- ALL. In addition, MDR1 expression in CD7+ AML/ALL might be responsible for the poor response to conventional chemotherapies of these types of leukemia.

Adult↗
PubMed1993

Molecular cloning, expression, and gene localization of a fourth melanocortin receptor.

The recent cloning of three melanocortin receptors suggests an unexpected diversity in this family of seven transmembrane G-protein linked receptors. Herein, we report the cloning, expression, and gene localization of a fourth human melanocortin receptor, the melanocortin-4 receptor. By Northern blot analysis and in situ hybridization, this receptor is expressed primarily in the brain, but its expression is notably absent in the adrenal cortex, melanocytes, and placenta. Agonist stimulation of COS-1 cells transiently transfected and L-cells permanently transfected with the coding region of the cloned melanocortin-4 receptor leads to increases in intracellular cyclic 3',5'-adenosine monophosphate. The profile of the responses of the melanocortin-4 receptor to different melanocortins distinguishes it from melanocortin receptors previously described. Using the technique of fluorescent in situ hybridization, the gene encoding the melanocortin-4 receptor was localized to chromosome 18 (q21.3).

Adrenocorticotropic Hormone↗
PubMed1993

Biologic characteristics of acute leukemia after myelodysplastic syndrome.

Ten patients with acute leukemia after primary myelodysplastic syndrome (MDS-AL) were examined to clarify the biologic nature of the leukemic cells in comparison with that of de novo acute myelocytic leukemia (AML). The morphologic and cytochemical features of the leukemic cells from all these patients corresponded well to those of de novo AML, and they were diagnosed with MDS-AML. Phenotypically, the frequent expression of the lymphocyte activation antigens, CD25 and CD30, was characteristic in MDS-AML. The in vitro response of MDS-AML cells to various growth factors was similar to that of de novo AML cells. Transforming growth factor beta 1 (TGF beta 1) suppressed growth factor-dependent colony formation by normal bone marrow cells, MDS bone marrow cells, and de novo AML cells, but did not inhibit colony formation by MDS-AML cells. The number of TGF beta 1 high-affinity binding sites of MDS-AML samples (< 5 to 47 sites/cell) was markedly lower than that in de novo AML samples (120 to 221 sites/cell). Our results indicate that the reduced TGF beta 1 may represent disregulation of the proliferation system in MDS-AML cells. This is thought to occur during the MDS phase, and may be related to the poorer response shown to conventional chemotherapy of AML.

Adult↗
PubMed1993

Clinical importance of CD7 expression in acute myelocytic leukemia. The Japan Cooperative Group of Leukemia/Lymphoma.

Forty patients (9 females and 31 males; mean age 41.9 years) with CD7+ acute myelocytic leukemia (AML) were investigated; they were classified into the following subgroups according to French-American-British classification: 15 M1, 18 M2, 3 M4, and 4 M5. Leukemic cells from all the patients were negative for T-cell-specific antigens, surface CD3, and T-cell-receptor molecules. The sex and age distributions were different from those of CD7- AML patients (P < .01). Hepatomegaly and central nervous system involvement were also frequent in the CD7+ AML patients. The phenotype of and responsiveness to hematopoietic growth factors by the leukemic cells showed their immaturity, as evidenced by frequent expression of CD34, HLA-DR, and TdT, and the greatest growth response to interleukin-3. No particular karyotypic abnormality was shown. One hundred eighty AML patients were treated with a therapeutic regimen routinely used for AML. The CD7+ AML patients showed a significantly lower response than CD7- AML patients (P < .01), and had a poorer prognosis (P < .01). CD7+ AML patients with M1 or M5b had unfavorable responses to the therapeutic regimen in comparison with patients with M2, M4, or M5a. In addition, 3 of 4 CD7+ CD2+ AML patients, who did not respond to the therapy, were induced into complete remission with an acute lymphoblastic leukemia therapy. The results presented here indicate the diagnostic importance of CD7 positivity in AML, suggesting that the cellular and clinical characteristics of CD7+ AML are sufficient for it to be recognized as a distinct category of AML.

Adolescent↗
PubMed1993

Molecular cloning of a novel melanocortin receptor.

Using the technique of the polymerase chain reaction primed with oligonucleotides based on the homologous transmembrane regions of seven transmembrane G protein-linked receptors, we isolated three full-length human genes that encode a novel subgroup of this receptor family. Recently, two of these receptors were identified as specific for alpha-melanocyte-stimulating hormone (alpha-MSH) and adrenocorticotropic hormone. We report the molecular cloning and pharmacologic characterization of a third member of this subgroup. The gene for this receptor encodes a protein of 361 amino acids in length. Its pharmacology characterizes it as an MSH receptor specific to the heptapeptide core common to adrenocorticotropic hormone and alpha-, beta-, and gamma-MSH. By Northern blot hybridization and polymerase chain reaction, it is expressed in brain, placental, and gut tissues but not in melanoma cells or in the adrenal gland. These findings may yield insight into the physiology of peptides derived from pro-opiomelanocortin post-translational processing.

Amino Acid Sequence↗
PubMed1993

Time-course of recovery of atrial contraction after cardioversion of chronic atrial fibrillation.

We aimed to study the time-course of recovery of atrial contraction after cardioversion of chronic atrial fibrillation (duration of more than 3 months) to sinus rhythm. Using M-mode, two-dimensional and pulsed Doppler echocardiography, we determined left atrial (LA) and ventricular (LV) dimensions, peak velocities, and velocity-time integrals of early and atrial filling velocity-time profiles in both LV and right ventricular (RV) inflows (peak E and peak A, Ea and Aa). Results of the LA and LV functions in seven elderly patients (an initial study group) were as follows. The extent of the LA dimensional reduction resulting from atrial contraction was significantly increased up to 5-8 weeks compared with values 0-1 day after cardioversion [from 1.3 +/- 0.8 (mean +/- SD) mm to 3.9 +/- 1.1, P < 0.01]. In conjunction with the progressive increase in peak A, the ratio of peak E to peak A (peak E/A) was significantly decreased and reached a plateau at 5-8 weeks (from 1.93 +/- 0.59 to 0.67 +/- 0.11, P < 0.01). LV fractional shortening was increased significantly 5-8 weeks after cardioversion (from 0.20 +/- 0.06 to 0.29 +/- 0.05, P < 0.01). Since a large part of the improvement in LA contraction was expected to occur in an early stage after cardioversion, we studied eight additional patients more frequently in the early stage (an additional study group). Furthermore, we studied the time course of LA and right atrial (RA) contractions.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Liver sarcoidosis showing low-density intrahepatic septa on postcontrast computed tomography.

The authors present a patient with massive liver sarcoidosis, showing only slight hepatomegaly on precontrast computed tomogram and multiple low-density intrahepatic septa on postcontrast computed tomogram. Sarcoidosis frequently involves the liver, but rarely shows abnormal findings other than hepatomegaly on computed tomograms. Only a few cases have demonstrated a low density intrahepatic area on computed tomograms. In this report, we present a patient with massive liver and pulmonary sarcoidosis, showing low density intrahepatic septa and pulmonary fibrosis on computed tomograms.

Humans↗
PubMed1993

Right atrial contractile performance in patients with myocardial infarction.

To evaluate right atrial (RA) contractile performance in patients with myocardial infarction, we validated a cineangiographic method of RA volume measurement, and investigated RA volume change in 'normal' individuals and patients with a previous myocardial infarction. Sixteen silicone rubber RA casts made from human cadavers were filmed in the postero-anterior and left lateral projections. The cast volumes calculated following Simpson's rule were in good agreement with those measured by water replacement (r = 0.992, P < 0.01). At cardiac catheterization, biplane RA cineangiography was performed in 19 'normal' individuals (N group), in 14 patients with a previous antero-septal infarction (AMI group) and in seven patients with a previous inferior infarction (IMI group). The RA volume-time curve was constructed at 20-40 ms intervals for one cardiac cycle. RA volume at the beginning of the atrial contraction (RAVd), which was defined as the 'preload' of the RA, tended to be larger in both the AMI and IMI groups compared with 'normal' individuals. The RA ejection volume was significantly larger in both the AMI (18.4 +/- 2.1 ml.m-2, P < 0.01) and IMI groups (19.4 +/- 2.8, P < 0.01) than in the N group (14.5 +/- 1.9), even for a comparable level of RAVd (range from 26 to 36 ml.m-2) (18.6 +/- 2.1, P < 0.01, 18.2 +/- 2.0, P < 0.01, 14.7 +/- 1.9, respectively). These results suggest that RA contraction increases in patients with myocardial infarction by increasing both the 'preload' and 'contractility' of the RA.

Adult↗
PubMed1993

Vitamin E is an important factor in T cell differentiation in thymus of F344 rats.

The effect of vitamin E (dl-alpha-tocopheryl acetate) on T cell differentiation in thymus of F344 rats was examined in this study. The rats were divided into three groups: vitamin E-free, regular and high vitamin E groups and fed a diet containing various levels of vitamin E (0, 50, and 585 mg/kg diet) for 7 weeks. The number of thymocytes was significantly lower in the vitamin E-free group relative to the regular group. Although the proportions of both CD4+CD8- and CD4-CD8+ T cells in thymocytes were significantly greater in the high vitamin E group, the proportion of CD4+CD8- T cells inversely decreased in vitamin E-free group compared to that of the regular group. The ratio of CD4+CD8-/CD4-CD8+ T cells increased in the high vitamin E group (p < 0.01) and significantly decreased in the vitamin E-free group (p < 0.001) compared to that of the regular group. Although the marked changes of T cell subsets were not seen in peripheral blood lymphocytes (PBL), the ratio of CD4+CD8-/CD4-CD8+ T cells was significantly lower in the vitamin E-free group and significantly greater in the high vitamin E group compared to that of the regular group. Production of interleukin (IL) 2 by thymocytes following the stimulation with Con A for 48 h increased about threefold in the high vitamin E group compared to the regular group. Conversely, thymocytes from rats fed the vitamin E-free diet showed a significant decrease of IL2 production compared to that of the regular group. Prostaglandin E2 (PGE2) production from thymocytes was significantly lower in the high vitamin E group compared to that of the regular group, whereas thymocytes of rats fed the vitamin E-free diet showed a significant increase of PGE2 production compared to that of rats fed the regular diet. Furthermore, in vitro addition of indomethacin provided a restoration of IL2 production from thymocytes of rats fed the vitamin E-free diet to the level of rats fed the regular diet. These results suggest that vitamin E plays an important role in T cell differentiation in thymus, which may be related to the action of vitamin E as antioxidant.

Animals↗