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Biomedical subjects

Y Abe

Publications and source records attributed to Y Abe.

At least 613 records · Page 34Linked to original sources
PubMed1994

Boron neutron capture therapy of malignant melanoma using 10B-paraboronophenylalanine with special reference to evaluation of radiation dose and damage to the normal skin.

A treatment regimen for boron neutron capture therapy of malignant melanomas is described using 10B-paraboronophenylalanine as the tumor-targeting compound. As a therapeutic dose, we adopted the maximum tolerable dose for the skin regardless of tumor 10B concentration. In practice, the maximum neutron fluence should be decided prior to starting irradiation. For this purpose, the kinetics of the concentration of 10B in the blood and skin and the skin-to-blood ratios were analyzed in the six patients who received 170 mg/kg of the compound intravenously, and skin concentrations during irradiation were predicted using a standard skin factor curve. This yields a skin concentration at time T based on the blood concentration at time 0. We calculated the maximum tolerable fluence yielding but not exceeding 18 RBE-Gy by assuming that the RBE of 14N(n,p)14C and 10B(n, alpha)7Li reaction for skin damage is 2.5. Actual skin reactions in three of five patients treated with the therapy were, as predicted, within tolerable limits, and we were able to obtain complete tumor regression in four cases. The results indicate that application of our logical approach will be useful for subsequent cases and further development of this therapy.

Aged↗
PubMed1994

[Pseudocoarctation of the aorta associated with aortic valve regurgitation: a case report].

We reported a case of pseudocoarctation of the aorta associated with severe aortic regurgitation. A 63-year-old male admitted with congestive heart failure due to aortic regurgitation. The blood pressure was 170/60 mmHg in the right arm and the systolic pressure was 132 mmHg in the right leg. To and fro murmur and diastolic grade IV/VI blowing murmur was heard along the lower left sternal border. Aortogram demonstrated marked buckling of the descending aorta at the origin of the left subclavian artery without collateral circulation and bicuspid aortic valve with severe aortic regurgitation. His pressure gradient across the pseudocoarctation was 40 mmHg in the preoperative catheterization. We performed an aortic valve replacement (AVR) without further surgical treatment. The pressure gradient was reduced to 10 mmHg and his symptom improved after AVR. These results suggested that pseudocoarctation of the aorta may require no surgical treatment in some case associated with aortic valve regurgitation because of improvement of high pressure gradient across it by AVR alone.

Aortic Coarctation↗
PubMed1994

[Short-term intensive consolidation chemotherapy in the treatment of acute nonlymphocytic leukemia].

Thirty-four adults with AML were treated with conventional remission induction chemotherapy consisting of Ara-C and daunorubicin. The median age was 55 years. Thirty (88%) patients showing complete remission (CR) were treated with four courses of intensive consolidation chemotherapy: course 1 with 7 days Ara-C and 4 days of mitoxantrone; course 2 and 7 days Ara-C, 5 days of etoposide, vincristine day 10 and vinblastine day 12 (A-Triple-V); course 3 with 7 days Ara-C and 3 days of aclacinomycin; course 4 with 7 days Ara-C and 3 days of daunorubicin. Then patients were observed without further therapy until relapse. The median duration of relapse-free survival for patients < 60 years of age was 13 months, with 49% patients projected to continue first CR at 52 months. In contrast, only 19% of patients 60 years or older were projected to be in CR at 22 months. Most patients experienced significant side effects including fever, liver dysfunction, pneumonia and septicemia during consolidation therapies. Short-term intensive consolidation therapy appeared to be efficacious for patients < 60 years of age. The results in older individuals were worse than expected, and the use of G-CSF was suggested to improve this problem.

Aclarubicin↗
PubMed1993

[Determination of potential doubling time using in vitro continuous labeling method with bromodeoxyuridine: estimation in head and neck squamous cell carcinoma].

Using in vitro continuous labeling with bromodeoxyuridine and immunohistochemical staining, potential doubling time (Tpot) was calculated in 24 patients with head and neck carcinoma treated with radiotherapy. There was no evident correlation between Tpot and tumor response in the cases treated with external irradiation. However, in one case of T2N0 mesopharyngeal carcinoma with short Tpot, tumor was microscopically residual even though it showed good radioresponsiveness during radiotherapeutic course. Meanwhile, all patients treated with brachytherapy showed complete response in spite of various Tpot. Tpot seems significant in the selection of fractionation to control head and neck carcinoma with external radiotherapy.

Brachytherapy↗
PubMed1993

The effect of crystallinity on hydroxyapatite-induced production of reactive oxygen metabolites by polymorphonuclear leukocytes.

To assess the role of crystallinity in biological response, we quantitated the generation of reactive oxygen metabolites in human polymorphonuclear leukocytes (PMN) with a chemiluminescence assay using three hydroxyapatite preparations with sintering temperatures of 1,200 degrees C and 900 degrees C and a drying temperature of 110 degrees C on the basis of equal weights (1 mg/ml). These crystals have almost the same average diameters and similar average zeta potentials. The crystals prepared at higher temperatures have higher crystallinity, or larger domain sizes, which were calculated by X-ray diffraction line broadening. The production of reactive oxygen metabolites by PMN in hydroxyapatite of 1,200 degrees C was 10-times that by PMN in hydroxyapatite of 900 degrees C and more than 50-times greater than that in hydroxyapatite of 110 degrees C. A single linear correlation was observed for a plot of log (peak chemiluminescence levels) vs. a plot of log (domain sizes). These results clearly show that the maximal effect of crystallinity on hydroxyapatite-induced production of reactive oxygen metabolites by human PMN was seen at higher crystallinity.

Crystallization↗
PubMed1993

CD7+ stem cell leukemia/lymphoma. Features of a subgroup without circulating blast cells.

Recent advances in immunology have clarified the cellular origin of hematopoietic neoplasms. Blast cells with a CD7+ CD4- CD8- phenotype are demonstrated to originate from malignant pluripotent hematopoietic stem cells. In this article, the authors describe three rare cases, designated as a lymphoma type of CD7+ stem cell leukemia/lymphoma, with clinical features described below. All three patients were admitted with non-Hodgkin lymphoma with a 2-month to 4-month history of lymphadenopathy. Histologic examination of lymph nodes showed lymphoblastic lymphoma (LBL) in all patients. Bone marrow blast cells had an immunophenotype consistent with CD7+ CD4- CD8- acute leukemia, although abnormal cells were not observed in the peripheral blood during the course of the disease. One patient had a recurrence in the bone marrow, with myeloperoxidase-positive blast cells expressing myeloid differentiation antigens. Chromosomal analysis detected a common abnormal karyotype initially and at relapse. Furthermore, the same T-cell receptor gene rearrangement was found initially and at relapse, suggesting that these blast cells originated from the same pluripotent leukemic clone. Additional studies on more patients are required to determine the clinical significance of this group, including the difference from CD7+ stem cell leukemia/lymphoma with circulating blast cells (leukemic type) or LBL.

Acute Disease↗
PubMed1993

Role of 55- and 75-kDa tumor necrosis factor membrane receptors in the regulation of intercellular adhesion molecules-1 expression by HL-60 human promyelocytic leukemia cells in vitro.

Most human cells express two TNF and lymphotoxin (LT) membrane receptors (TNF-R), of 55 and 75 kDa. The regulatory effect of these two receptors on intercellular adhesion molecules (ICAM-1) expression was examined in various human cell lines in vitro, including human lymphokine-activated killer T cells (T-LAK) cells and HL-60 cells. Rabbit antihuman TNF-R antisera specific for each receptor were employed as probes to selectively stimulate 55- and 75-kDa TNF/LT membrane receptor production. These antisera compete with TNF/LT binding to each specific cell membrane receptor and have been found to bind to specific membrane receptors on various human cell lines in vitro. In the present study, we demonstrated biologic activity for anti-55-kDa TNF-R antiserum. For example, antibodies that bind to the 55-kDa TNF-R caused cytolysis of HeLa and ME-180 human cervical cancer cells and induced proliferation of MRC-5 human fibroblasts. In contrast, however, anti-75-kDa TNF-R antiserum demonstrated no bioactivity in these assays. In addition, no synergy or costimulation was observed when a combination of both anti-55- and anti-75-kDa TNF-R antisera were tested in these assay systems. Anti-55-kDa TNF-R antiserum up-regulated ICAM-1 expression on human HL-60, T-LAK, and THP-1 cells, whereas anti-75-kDa TNF-R antiserum had no effect. Unexpectedly, however, ICAM-1 expression was greatly enhanced by the addition of anti-75-kDa TNF-R to the anti-55-kDa TNF-R containing culture. This enhancing effect was also observed with human T-LAK cells and THP-1 monocytic leukemia cell, in vitro.

Binding Sites, Antibody↗
PubMed1993

Asparaginyl endopeptidase of jack bean seeds. Purification, characterization, and high utility in protein sequence analysis.

Asparaginyl endopeptidase was highly purified from mature seeds of the jack bean (Canavalia ensiformis). The final enzyme preparation showed a single peak in high-performance liquid chromatography on a reversed-phase column, and the material in the peak gave the following NH2-terminal amino acid sequence on Edman degradation for 25 cycles: H-Glu-Val-Gly-Thr-Arg-Trp-Ala-Val-Leu-Val-Ala-Gly-Ser-Asn-Gly-Tyr-Gly-Asn-Tyr- Arg-His-Gln-Ala-Asp-Val-. Behavior of the enzyme toward various protease inhibitors suggested that it belongs to a family of cysteine proteases. Strict substrate specificity of this enzyme was verified by the use of 14 polypeptide substrates including those derived from proteins. Almost all the peptide bonds on the carboxyl side of Asn residues were susceptible to the enzyme. The exceptions were cases where the residue was at the NH2 terminus or the second position from the NH2 terminus of substrates and where it was N-glycosylated Asn. Peptide bonds on the carboxyl side of any other amino acid residues were not cleaved. These properties promise the high utility of this novel endopeptidase in protein sequence analysis. Identity of jack bean asparaginyl endopeptidase with a processing enzyme responsible for maturation of concanavalin A from its precursor is also discussed.

Amino Acid Sequence↗
PubMed1993

Inhibition of Corynebacterium parvum-primed and lipopolysaccharide-induced hepatic necrosis in rats by selective depletion of neutrophils using a monoclonal antibody.

To examine whether neutrophils are involved in the pathogenesis of experimental liver dysfunction, we observed the effect of selective in vivo neutrophil depletion by a monoclonal antibody (RP-3) on the pathogenesis of acute experimental hepatic necrosis in rats induced by a preparative injection of heat-killed Corynebacterium parvum and a challenging dose of lipopolysaccharide (LPS) (positive control group). The serum transaminase titer 8 h after LPS injection was reduced by selective depletion of peripheral blood neutrophils as a result of RP-3 treatment (RP-3 group). A kinetic study showed that the serum transaminase titer of the RP-3 group was significantly lower than that of the positive control group from 4 to 24 h after LPS injection. The transaminase level was significantly lower in the group with less than 400/mm3 peripheral blood neutrophils than in the group with a greater number. The effect of RP-3 on the transaminase level was due neither to the injection of cancer ascites nor to RP-3 injection with the accompanying decrease in complement titer. These results suggest that neutrophils play an important role in the induction of liver dysfunction in this system.

Animals↗
PubMed1993

Operative stress potentiates the inductivity of membrane associated lymphotoxin (mLT) on lymphokine activated killer (LAK) cells in vitro.

Membrane-associated lymphotoxin (mLT) is induced in human peripheral blood mononuclear cells when cultured with interleukin 2, in the form of lymphokine-activated killer (LAK) cells. The inductivity of mLT is thought to be dependent upon the differentiation potential of LAK cell precursors, being T cells and natural killer cells. In this study, we investigated the inductivity of mLT on LAK cells from surgical patients. The preoperative values of mLT inductivity were found to be generally higher in malignant than benign cases, and the postoperative time course of mLT inductivity showed a transient decrease immediately after the operation followed by gradual increase over 2 weeks. Moreover, patients with an intraoperative bleeding volume of more than 1,000 ml showed a delay in the postoperative increase of mLT inductivity. These data suggest that operative stress potentiates the inductivity of mLT on LAK cells; however, excess stress may cause a delay in the restoration of mLT inductivity.

Adult↗
PubMed1993

Natural human IgG inhibits the production of tumor necrosis factor-alpha and interleukin-1 alpha through the Fc portion.

The overproduction of cytokines such as the tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 alpha (IL-1 alpha) may cause further deterioration in the already critical condition of patients with shock, sepsis, and acute inflammation. The effectiveness of infusion therapy of natural human IgG to such patients is suggested to depend partly upon the inhibition of the productivity of these cytokines. In this study, we investigated the modulation effects of IgG and its fragments on the production of TNF-alpha and IL-1 alpha, on human peripheral blood mononuclear cells (PBMC). The production of TNF-alpha and IL-1 alpha was found to be dose-dependently inhibited by IgG when stimulated by lipopolysaccharide (LPS), phytohemagglutinin (PHA), concanavalin A (Con A), and interleukin-2 (IL-2). However, no inhibition was seen when stimulated by phorbormyristate acetate (PMA). The F(ab')2 fragment showed enhancing effects on cytokine production by LPS, while the Fc fragment showed not as much inhibitory effect as whole intact IgG. IgG showed no direct cytotoxic effect on PBMC. These data suggest that natural human IgG inhibits TNF-alpha and IL-1 alpha production by PBMC through the Fc portion. The results of this study led us to conclude that whole intact IgG may be the best form of therapeutic delivery.

Cells, Cultured↗
PubMed1993

Differentiation and mineralization in osteogenic precursor cells derived from fetal rat mandibular bone.

The process of mineralization in cells prepared either by neutral protease digestion (Pro I) or by collagenase digestion (fifth cycle, Col V) from fetal rat mandible was studied in vitro. Alkaline phosphatase (ALPase) activity of cells in Pro I was low on day 3, increased rapidly from day 8, and reached a maximum on day 16, whereas that in Col V was high on day 2, then declined and thereafter elevated to reach a maximum on day 13. Both cell populations synthesized type I collagen in cell matrix and medium. Type III collagen was observed in cell matrix of Pro I on day 14 and 21. There was alpha 2 band of type V collagen in cell matrix of Pro I on day 21. Calcium deposition could be detected from day 14 in Pro I and from day 19 in Col V. The von Kossa-positive nodules were found on day 17 in Pro I and day 21 in Col V, respectively. The extracellular matrix in Pro I electron-microscopically consisted of well-banded collagen fibrils with a large number of calcified spherules. An elevation of ALPase activity, collagen synthesis, and mineral deposition occurred sequentially with a time lapse in Col V, and almost simultaneously in Pro I. The number of mineralized nodules was correlated with the density of plated cells in Pro I, but not in Col V. Dexamethasone caused an increase in the number of mineralized nodules in Pro I, but not in Col V, suggesting that Pro I contained osteoprogenitor cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗