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Biomedical subjects

N Uchida

Publications and source records attributed to N Uchida.

At least 163 records · Page 9Linked to original sources
PubMed1993

Steel factor influences the distribution and activity of murine hematopoietic stem cells in vivo.

To determine the effects of steel factor (SIF) on the number and distribution of phenotypically defined hematopoietic stem cells in vivo, mice were treated with continuous s.c. infusions of SIF for up to 7 days. The bone marrow demonstrated a transient 5-fold increase in the number of c-kit-positive lineage-negative/low cells with no change in cellularity. The radioprotective capacity of bone marrow cells was significantly reduced, and a 30% decrease in Thylo Lin-/lo Sca-1+ stem cells (Sca+ cells) was observed. In marked contrast, in the spleen a 2-fold increase in cellularity was accompanied by a 24-fold increase in c-kit-positive lineage-negative/low cells. SIF-treated spleen cells provided increased radioprotection and a corresponding 4-fold increase in the number of Sca+ cells. In the peripheral blood, an increase in both neutrophils and lymphocytes resulted; however, the number of c-kit-positive lineage-negative/low cells remained < 1%. SIF produced a 25-fold increase in radioprotection capacity and a 20-fold increase in the number of Sca+ cells in the peripheral blood. The increased radioprotection capacity of both the spleen cells and peripheral blood cells was associated with donor-derived, long-term multilineage reconstitution of recipient mice. The total number of Sca+ cells isolated per mouse after SIF treatment was not significantly increased. These results show that exogenous SIF treatment causes a redistribution of Sca+ cells and stem cell activity while having little effect on the total number of stem cells in the mouse.

Animals↗
PubMed1993

Compliance effects on small diameter polyurethane graft patency.

Microporous compliance matched and noncompliant grafts were compared in a dog carotid artery interposition model. We fabricated 4 mm diameter sponge type polyurethane (Biomer) tubes 5 cm in length with a 0.5 mm wall thickness. The luminal surface was covered with a 50 microns coating of cross-linked gelatin. Compliance was measured in vitro and in vivo by volume and vessel diameter changes. Over a mean arterial pressure range of 55-155 mm Hg, the diameter changes of grafts and stump arteries were measured in situ using an ultrasonic Hokanson device. Compliance matched grafts were found to have the same in vitro compliance values as the natural canine carotid at a mean arterial pressure of 100 mm Hg. Compliance matched and noncompliant grafts had values of 10.3 +/- 1.3 and 0.9 +/- 0.1 x 10(-2) mm Hg, respectively. End to end arterial anastomoses were constructed between the graft and the host arteries. The use of synthetic grafts with matched compliance to the adjacent natural vessels has been advocated as the ideal solution to circumvent the problems of graft failure. These studies indicate that compliance values for compliance matched grafts decreased immediately after implantation (from 10.3 to 6.5 x 10(-2) %/mm Hg) and within 6 weeks decreased to 3.6 x 10(-2) %/mm Hg. The compliance values for noncompliant grafts remained constant throughout the test period. At autopsy all grafts showed a tightly adhered tissue capsule. The thickness of the anastomotic hyperplasia at the distal sites of compliance matched grafts was significantly different (P < .05) than that of the adjacent artery. The patency for compliant and noncompliant grafts was 64% and 50%, respectively. Evidence for polyurethane graft degradation was obtained by Fourier transform infrared spectroscopy and gel permeation chromatography analysis of patent explants. Compliance mismatch alone does not contribute to graft failure, however, material degradation, suture technique and/or capsule formation can play a contributory role although these were not tested directly.

Animals↗
PubMed1993

A model for cell killing by continuous heating.

Based on an analysis of cellular survival curves following single heating, a model is proposed to explain the action of heat on cell survival. The basic idea of this model is that cellular inactivation by heat is a three-step process. In the first step, heating produces sublethal damage. Secondly, the produced damage is repaired in a certain time period after the cell has received it. The time period to be required for repairing the sublethal damage changes with the thermal conditions that the cell has undergone. In the third step, the lethal event is induced when the cell undergoes cumulative sublethal damage to the extent that it cannot be repaired. The incidence of sublethal damage is calculated using the Arrhenius equation, where one inactivation energy is postulated. Based on the assumption that sublethal damage occurs at random, a mathematical model has been worked out that quantitatively describes cell killing by single heating. This mathematical model has been applied to the surviving fractions of Chinese hamster ovary cells reported by Sapareto, and it correlates to the whole surviving data at a temperature range of from 41.5 to 46 degrees C by the substitution of the appropriate values for the parameters of the model.

Animals↗
PubMed1993

MR imaging of vertebral metastases: evaluation of fat saturation imaging.

OBJECTIVE: To compare conventional T1-weighted imaging (SE-T1) and chemical shift fat-saturation T1-weighted imaging (FS-T1) in the diagnosis of bone metastases. SUBJECTS: Twenty-two patients (101 vertebrae) with non-neoplastic lesions (Group 1) and 21 patients (72 vertebrae) with spinal metastases (Group 2) were evaluated with both images. RESULTS: The signal intensity (SI) distribution of Groups 1 and 2 on SE-T1 showed various patterns, and SI measurement was not significantly different between the two groups. On FS-T1, all non-neoplastic lesions had a low-intensity homogeneous appearance; however, the metastases had mixed to high SI. The SI measurement data of Group 2 was significantly (P < 0.0001) higher than that of Group 1. CONCLUSION: FS-T1 was useful in evaluating vertebral metastases.

Adult↗
PubMed1993

Antioxidants in the serum of children with insulin-dependent diabetes mellitus.

To determine whether alteration in serum antioxidant status is related to the increased oxidative stress as a cause of diabetic angiopathy, we measured both the antioxidant activity (AOA) and total peroxyl radical-trapping antioxidant parameter (TRAP), and their component individual antioxidants in serum of children with insulin-dependent diabetes mellitus (IDDM). The AOA was measured as the ability to inhibit lipid autoxidation in brain homogenates. TRAP was assayed as the ability to delay lipid peroxidation induced by an azo initiator. Antioxidants measured were ceruloplasmin, transferrin, and albumin as components of AOA; and ascorbic acid, uric acid, protein sulfhydryl, and alpha-tocopherol as components of TRAP. Serum AOA appeared to be decreased in the diabetics in relation to poor glycemic control, corresponding to the decrease in transferrin and albumin. Serum haptoglobin level was also decreased in the diabetics. Similarly, the directly measured TRAP value was decreased in the diabetic serum mainly due to the decreased contribution of unidentified chain-breaking antioxidants, despite the increase in ascorbic acid and alpha-tocopherol. The decrease in both types of antioxidant activity in the diabetic serum, as new findings, suggests that a defective serum antioxidant status contributes to the increased oxidative stress in IDDM.

Adolescent↗
PubMed1993

Heterogeneity of hematopoietic stem cells.

Hematopoietic stem cells are capable of multi-lineage differentiation to all blood cell types as well as self-renewal and radioprotection. Thy-1.1lo Lin-/lo Sca-1+ cells are a heterogeneous mixture of quiescent and self-renewing hematopoietic stem cells as well as multi-lineage expanding cells.

Animals↗
PubMed1993

Functional heterogeneity is associated with the cell cycle status of murine hematopoietic stem cells.

Hematopoietic stem cells (HSCs) are characterized by their ability to differentiate into all hematopoietic cell lineages while retaining their capacity for self renewal. One of the predictions of this model is the existence of a heterogeneous pool of HSCs, some members of which are destined to become lineage restricted progenitor cells while others function to renew the stem cell pool. To test whether HSCs are heterogeneous with respect to cell cycle status, we determined the fraction of phenotypically defined murine HSCs (Thy1.1lo Lin-/lo Sca-1+) that contain > 2n amount of DNA as measured by propidium iodide staining, Hoechst dye uptake and [3H]thymidine labeling; that fraction is 18-22%. In contrast, in the developing fetal liver, 40% of HSCs are in the S/G2/M phases of the cell cycle. Those HSCs which exhibit a low level of staining with rhodamine 123 are almost exclusively in G0/G1 (97%) whereas only 70% of HSCs which stain brightly for rhodamine 123 are in G0/G1. The injection of 100 G0/G1 HSCs rescued 90% of lethally irradiated mice in contrast to 100 S/G2/M HSCs, which protected only 25% of lethally irradiated recipients. Enhanced long-term donor-derived multilineage reconstitution of the peripheral blood was observed in recipients of 100 G0/G1 HSCs compared to recipients of 100 S/G2/M cells. These data indicate that a significant proportion of HSCs are actively proliferating during steady state hematopoiesis and that this subpopulation of cells exhibits reduced stem cell activity.

Animals↗
PubMed1993

Dispersed cell culture of human sweat duct cells under serum-free conditions.

Human eccrine gland duct cells were successfully cultured using a serum-free medium, K-GM medium. Eccrine sweat ducts were isolated from dispase treated skin specimens from palms or soles. After treatment of the isolated ducts with trypsin and EDTA, dispersed cells were cultured in K-GM medium. In primary cultures, small colonies were seen 3 to 4 days after inoculation. Then the cells rapidly proliferated and formed large colonies with a paving stone-like cell arrangement. During the culture, small dome shaped areas were sometimes formed in the centers of colonies. Cultures multiplied for a maximum of 7 passages. The plating efficiencies of the 1st to 6th passage cells were about 20% to 30%. Immunocytochemically, cultured cells were positively stained with anti-carcinoembryonic antigens, K8.37 and K8.13, but not with anti-S100 protein, anti-HLA-DR, 34 beta B4, or PKK3. An electron micrograph of the cultured cells showed a multilayer of flattened cells linked by desmosomes. These results indicate that the cultured cells possessed the staining properties compatible with those of the ductal portion of eccrine sweat glands. No contamination by other mesenchymal cells, such as fibroblasts, was seen during the culture.

Antigens↗
PubMed1993

Risk analysis of low cardiac output syndrome after valve replacement.

In order to obtain a better understanding of the pathogenesis of the postoperative low cardiac output syndrome (LOS), a multivariate regression analysis was performed, evaluating predictive risk factors quantitatively as a function of plural preoperative variables. A total of 145 cases including 76 MVR (MS 36 MR 40), 42 AVR and 27 DVR were analyzed in this study. Ten historical, 10 hemodynamic and 4 operative risk factors were collected to compose the data file with corresponding status of postoperative cardiac function which was classified as follows. Patients who were not associated with postoperative LOS (Score 1), associated with the LOS which required and responded to ordinal dosage of a catecholamine (Score 2) associated with the LOS which required and responded to maximal dosage of the catecholamine and/or mechanical circulatory support (Score 3), and died of LOS (Score 4). Variables with significant relationships to postoperative LOS, regression equation to LOS score and their multiple correlation coefficients (R) of each group were as follows. MVR group: technical trouble (TT), extracorporeal circulation time (ECCT), change of myocardial preservation methods, delta LVSWI/delta LVEDP, diseased duration, aortic cross clamping time, CTR, Y = -1.16 + 1.01 (TT) + 0.05(ECCT) + 0.16(delta LVSWI/delta LVEDP) + 0.02(CTR), R = 0.76. AVR group: LVMMI, ECCT, cardiac failure, NYHA, Y = -0.71 + 0.03(LVMMI) + 0.004 (ECCT) + 0.22(NYHA), R = 0.78. DVR group: delta LVWI/delta LVEDP, LVMMI, NYHA, LV diastolic eccentricity ratio, ECCT, Y = -0.50 + 0.60 (delta LVWI/delta LVEDP) + 0.003(LVMMI) + 1.18(NYHA) + 0.38(delta LVSWI/delta LVEDP) + 0.003(ECCT), R = 0.87. It was demonstrated that preoperative ergometer exercise study during cardiac catheterization was useful in prediction of postoperative outcomes, especially in the MVR (MS) group.

Adult↗
PubMed1993

Localization of proliferating cell nuclear antigen in aural cholesteatoma.

Middle ear cholesteatoma is not a genuine tumor but has a remarkable proliferative activity which causes serious destruction of the mastoid bone. In the present study, we used immunohistochemistry with antiproliferating cell nuclear antigen (PCNA) antibody on cholesteatomatous tissues to evaluate the localization of PCNA, as it has been said that PCNA is a very available protein for showing cell proliferative activity. Moderately concentrated PCNA was demonstrated within the germinal basal layer cells of the cholesteatomatous epithelium in three of eight surgical specimens. Furthermore, in one case of very active osteolytic cholesteatoma, PCNA activity was demonstrated in the mesenchymal cells, probably fibroblast-like cells, in direct contact to the destroying mastoid bone lesions. Although the etiology and histopathology of the invasive and proliferative activity of middle ear cholesteatomatous tissues are unclear, this observation suggests that immunohistopathological examination using PCNA antibody might be a useful tool for evaluating bone resorption activity and for establishing the prognosis of various types of cholesteatoma.

Adolescent↗
PubMed1993

[A new sequential chemotherapy of methotrexate with 5-fluorouracil against advanced colo-rectal cancer].

A new sequential chemotherapy consisting of intravenous (IV) administration of methotrexate (MTX) 50 mg/m2 followed by 3 equal IV doses of 5-fluorouracil (5-FU) 500 mg/m2 at 1.4 and 21 hrs. and a leucovorin rescue (15 mg/body/8 hr) from 24 hrs. after MTX for 3 days was applied every two weeks for the patients with advanced colo-rectal cancer. The effectiveness of this MTX/3-dose 5-FU regimen was compared retrospectively with that of the standard sequential regimen consisting of the IV administration of MTX 100 mg/m2 followed by a single IV dose of 5-FU 800 mg/m2 one hr. later and a leucovorin rescue (21 mg/body/6 hr) 24 hrs. later given every week, namely MTX/1-dose 5-FU regimen. Partial response was achieved in 7 (46.7%) of 15 evaluable patients with the MTX/3-dose 5-FU regimen and in 3 (13.6%) of 22 evaluable patients with the MTX/1-dose 5-FU regimen (p < 0.05). The median survival times were 13 and 9 months, respectively. There were no significant difference in the patient characteristics between the two groups, and the toxic effects were much lower in the MTX/3-dose 5-FU than in the MTX/1-dose 5-FU regimen. It is therefore, concluded that the MTX/3-dose 5-FU regimen is superior to the standard MTX/1-dose 5-FU regimen.

Adult↗
PubMed1993

[A case of surgery for AAE with dissection extended to right coronary artery--device for reconstruction of coronary artery and retrograde cardioplegia and retrograde cerebral perfusion].

We experienced a surgical case of aortic dissection (Stanford type A) with annuloaortic ectasia in Marfan Syndrome. A 45-year-old female who had been diagnosed as Marfan Syndrome three years age was emergently admitted to our hospital with sudden chest pain. We diagnosed this case as aortic dissection of Stanford type A by ultrasonic cardiogram and thoracic CT. The ascending aorta was replaced with composite graft by modified Bentall procedure, right coronary artery was bypass to segment 2 using vein graft and left coronary artery was interposed by Dacron graft. During operation we utilized retrograde cold blood cardioplegia for cardiac arrest (180 min.) and retrograde cerebral perfusion accompanied with total circulatory arrest (45 min.). No complication such as cardiac damage and cerebral damage was found postoperatively. We discussed surgical method for aortic dissection with anuloaortic ectasia in particular reconstruction of coronary artery, cardioplegia and cerebral protection.

Aortic Dissection↗
PubMed1992

Development of gamma delta T-cell subsets from fetal hematopoietic stem cells.

Hematopoietic stem cells (HSC) were isolated from mouse fetus, and their developmental potential was compared with adult HSC. Donor-derived V gamma 3+T cells were detected in fetal thymic lobes, repopulated in vitro with fetal liver HSC, but not in those with adult bone marrow HSC. Single clonogenic fetal HSC gave rise to thymic progeny that include V gamma 3+, other gamma delta+, and alpha beta+ T cells. No V gamma 3+ T cells were detected in adult thymus injected intrathymically with either fetal or adult HSC. These results support a hypothesis that only fetal HSC have the capacity to differentiate into V gamma 3+ T cells in the fetal thymic microenvironment, and that the developmental potential of HSC may change during ontogeny.

Aging↗
PubMed1992

Searching for hematopoietic stem cells: evidence that Thy-1.1lo Lin- Sca-1+ cells are the only stem cells in C57BL/Ka-Thy-1.1 bone marrow.

Hematopoietic stem cells (HSCs) are defined in mice by three activities: they must rescue lethally irradiated mice (radioprotection), they must self-renew, and they must restore all blood cell lineages permanently. We initially demonstrated that HSCs were contained in a rare (approximately 0.05%) subset of bone marrow cells with the following surface marker profile: Thy-1.1lo Lin- Sca-1+. These cells were capable of long-term, multi-lineage reconstitution and radioprotection of lethally irradiated mice with an enrichment that mirrors their representation in bone marrow, namely, 1,000-2,000-fold. However, the experiments reported did not exclude the possibility that stem cell activity may also reside in populations that are Thy-1.1-, Sca-1-, or Lin+. In this article stem cell activity was determined by measuring: (a) radioprotection provided by sorted cells; (b) long-term, multi-lineage reconstitution of these surviving mice; and (c) long-term, multi-lineage reconstitution by donor cells when radioprotection is provided by coinjection of congenic host bone marrow cells. Here we demonstrate that HSC activity was detected in Thy-1.1+, Sca-1+, and Lin- fractions, but not Thy-1.1-, Sca-1-, or Lin+ bone marrow cells. We conclude that Thy-1.1lo Lin- Sca-1+ cells comprise the only adult C57BL/Ka-Thy-1.1 mouse bone marrow subset that contains pluripotent HSCs.

Animals↗
PubMed1992

Three cell lines showing androgen-dependent, -independent, and -suppressed phenotypes, established from a single tumor of androgen-dependent Shionogi carcinoma 115.

We investigated the heterogeneity of cells in terms of androgen responsiveness within a single tumor mass of Shionogi carcinoma SC-115 showing androgen-dependent growth. After cloning of the tumor by the limiting dilution method in the presence of androgen, we isolated 40 clones at random. Twenty-two clones required androgen for growth (androgen-dependent phenotype), 16 did not (androgen-independent phenotype), and the remaining two clones showed growth inhibition when androgen was added (androgen-suppressed phenotype). In addition, 22 androgen-dependent clones showed heterogeneity in growth factor sensitivity in the absence of androgen. All clones were sensitive to both acidic and basic fibroblast growth factor (FGF), 7 of 22 clones were sensitive to epidermal growth factor (EGF) and transforming growth factor (TGF)-alpha, and 2 of 22 clones were sensitive to TGF-beta. This preexisting heterogeneity may be partly responsible for the growth of androgen-dependent tumor under hormone-deprived circumstances. Three typical clones, SC2G, SC1G, and SC4A, were selected from androgen-dependent, -independent, and -suppressed phenotypic groups, respectively. These clones, as well as original solid tumors, were found to produce heparin-binding growth factors of heterogeneous elution positions. The molecular nature of these growth factors is not yet known. Neither anti-basic FGF antibody nor anti-EGF antibody inhibited the cell growth when added in cell culture, suggesting the factors were distinct from basic-FGF and EGF.

Androgens↗
PubMed1992

Maintenance of androgen-, glucocorticoid- or estrogen-responsive growth in shionogi carcinoma 115 subline sustained in castrated mice with high dose of estrogen for 30 generations (3 years).

Shionogi carcinoma 115 (SC115), an androgen-dependent mouse mammary tumor, rapidly loses its androgen responsiveness after androgen withdrawal. The growth of this tumor can also be stimulated by high doses of estrogen or glucocorticoid. In the present study, the maintenance of hormone-responsive growth of SC115 tumors with a high dose of estrogen was examined in castrated male mice using an SC115 subline obtained by serial transplantations of SC115 tumors in estrogen-treated castrated mice for 3 years (30 generations) (subline E2). Seed tumors from both SC115 and subline E2 could rapidly grow in castrated mice given daily injections of testosterone propionate (TP), 17 beta-estradiol (E2), or dexamethasone (Dex) (100 micrograms/mouse/day) but not in those given vehicle alone. Although SC115 and subline-E2 tumors grown with TP or Dex showed temporary regression after steroid withdrawal, the tumors grown with E2 did not show such temporary regression. The TP-, E2-, or Dex-induced growth of subline-E2 tumors was almost the same as that of the original SC115 tumors. However, responsiveness to androgen, estrogen or glucocorticoid of both tumors disappeared within one passage in steroid-depleted castrated mice. The present findings demonstrate that the loss of responsiveness to androgen as well as to high doses of estrogen or glucocorticoid of SC115 tumors can be prevented in castrated mice not only with androgen but also with high doses of estrogen.

Animals↗
PubMed1992

Lymphocyte development from stem cells.

Highly enriched pluripotent and multipotent hematopoietic stem cells (HSCs) are isolated from bone marrow and fetal liver as Thy-1loLin-Sca-1+ cells. Pluripotent HSCs express c-kit receptor on their surface, but the generation and proliferation of early fetal HSCs take place in the absence of steel factor. T precursor cells migrate into the fetal thymus by chemotactic mechanism. CD4lo precursors represent a newly defined phase of T-cell development in the thymus between the bone marrow-derived stem cells and the CD4-8- intrathymic precursors. Only fetal, but not adult, HSCs have the capacity to differentiate into V gamma 3+ and V gamma 4+ T cells under the fetal thymic microenvironment, and HSC themselves may lose some of their developmental potential during ontogeny. It is postulated that HSCs are the locus of a complicated but precise developmental clock that may determine both the time-dependent closure of some gene loci (e.g. V gamma 3 and V gamma 4 T cell receptor, and embryonic and fetal globin) and the activation of others (e.g. the N nucleotide insertion machinery).

Animals↗