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Biomedical subjects

Y Hoshi

Publications and source records attributed to Y Hoshi.

At least 163 records · Page 9Linked to original sources
PubMed1994

Umbilical cord blood as a rich source of immature hematopoietic stem cells.

To investigate immaturity of hematopoietic progenitor cells in umbilical cord blood mononuclear cells (CB-MNC), the formation of macroscopic colonies and mixed-cell colonies was assayed by methylcellulose culture with various combinations of cytokines (stem cell factor [SCF], interleukin [IL]-3, IL-6, granulocyte-colony stimulating factor [G-CSF], erythropoietin [EPO]) and compared with bone marrow (BM)-MNC. Moreover, distribution of the subpopulations divided by CD34, CD38, HLA-DR and CD33 was compared by flow-cytometry. Colonies derived from CB-MNC were so large that they could be observed with the naked eye and consisted of a variety of types of hematopoietic cells. Mixed-cell colonies were formed to a much greater extent in CB-MNC than in BM-MNC. Addition of EPO, IL-3, and SCF had rapid effects on the growth of mixed-cell colonies. The subpopulations of immature hematopoietic progenitor cells (CD34+, CD38-, HLA-DR-), which are supposed to be able to differentiate into hematopoietic precursors and stromal cells, were significantly higher in CB-MNC (8.7 +/- 6.6%) than in BM-MNC (0.0 +/- 0.1%; P < 0.001). These results suggest that CB is a rich source of immature hematopoietic progenitor cells compared to BM.

Antibodies, Monoclonal↗
PubMed1994

[Studies on respiratory infections in primary care clinic (V). The pattern of distribution on bacteria, Mycoplasma pneumoniae and virus isolated from patients with respiratory infections, who were seen in six private clinics, and clinical efficacy of ciprofloxacin and roxithromycin].

The pattern of distribution of bacteria, Mycoplasma pneumoniae and virus isolated from the same specimen recovered from the throat swab or the sputum of 479 patients with respiratory infections who were seen in six private clinics in Sendai City of Japan during the period from October to November in 1992 (period I) and from January to February in 1993 (period II) was documented. Of the 479 patients, 234 had acute pharyngitis, 145 had acute bronchitis, 96 had influenza, 21 had acute tonsillitis, 5 had acute pneumonia and 9 had other respiratory infections. One hundred (42.4%) strains of potential pathogen and one strain of M. pneumoniae were recovered from 236 cases in period I, and 66 (27.2%) strains of potential pathogen, one strain of M. pneumonae and 73 strains of Influenza virus (30.0%: 43 of type A Hong-Kong and 30 of type B) from 243 cases in period II. Of the 166 strains, major isolates were Staphylococcus aureus (56 strains), Streptococcus pneumoniae (12 strains), Streptococcus pyogenes (15 strains), Haemophilus influenzae (17 strains), Esherichia coli (4 strains), Klebsiella spp. (35 strains), Pseudomonas aeruginosa (4 strains) and Acinetobacter spp. (23 strains). Only one strain of S. aureus was resistant to methicillin (MIC: 50 micrograms/ml). None of S. pneumoniae was resistant to 1 microgram/ml of ampicillin. Ciprofloxacin was administered to 113 cases and roxythromycin to 220 cases by doctors in charge.(ABSTRACT TRUNCATED AT 250 WORDS)

Ciprofloxacin↗
PubMed1994

Peripheral blood progenitor cell transplantation estimated by three-colour (CD34, HLA-DR, CD33) flow cytometry.

The relationships between transfused cell number of CD34+ cell subpopulations divided by HLA-DR and CD33 antibodies and hematopoietic recovery patterns after peripheral blood progenitor cell transplantation (PBPCT) subsequent to myeloablative chemoradiotherapy were investigated in 14 children with cancer. Both logarithm of transfused CD34+ cell number/10(6)/kg and logarithm of transfused cell number/10(6)/kg of the CD34+HLA-DR+CD33+ subpopulation, which is supposed to be myeloid-committed cells, were correlated with myeloid recovery after PBSCT, though they were not correlated with erythroid or platelets recovery. On the other hand, logarithm of transfused cell number/10(6)/kg of CD34 + HLA-DR-CD33-subpopulation, which is supposed to be immature progenitor cells, was not correlated with myeloid recovery but correlated with erythroid recovery and platelet recovery. These results suggested that rapid myelopoiesis after PBPCT occurs following transfusion of sufficient numbers of myeloid-committed cells and complete hematopoietic reconstitution occurs after transfusion of sufficient numbers of immature hematopoietic progenitor cells.

Adolescent↗
PubMed1994

[Effective combination therapy by recombinant erythropoietin and cepharanthin in a girl with refractory anemia].

A 3-year-old girl was admitted with a one-month history of a tendency to bleed to Jikei Kashiwa hospital in May, 1992. She developed pancytopenia as follows; hemoglobin: 8.6 g/dl, red blood cell: 316 x 10(4)/microliters, reticulocyte: 9,480/microliters, white blood cell: 2,500/microliters (neutrophil: 400/microliters) and platelet count: 2.7 x 10(4)/microliters. Her bone marrow was hypoplastic, but was so dysplastic in 3 cell-lines as to be diagnosed as hypoplastic refractory anemia. After two courses of methylprednisolone pulse therapy followed by oral prednisolone therapy which were not effective and were supplemented by blood transfusions, the treatment of 20mg/day oral Cepharanthin, a biscoclaurine alkaloid, and intravenous recombinant human erythropoietin (rhEPO) twice a week at dose of 6,000 U/week was initiated in January, 1993. About 3 months later she showed a steady rise in hemoglobin concentration (from 4.1 to 11.9 g/dl) and platelet count (from 4,000 to 39,000/microliters). Although the rhEPO was tapered and ceased in September, 1993, her hemoglobin concentration has ranged from 11.0 to 11.9 g/dl and her platelet count from 30,000 to 40,000/microliters by giving her Cepharanthin and low dose prednisolone.

Alkaloids↗
PubMed1993

Dynamic changes in cerebral oxygenation in chemically induced seizures in rats: study by near-infrared spectrophotometry.

Using near-infrared spectrophotometry, the redox state of copper in cytochrome oxidase, and the hemoglobin oxygenation state were measured in the rat brain in situ during and after chemically induced seizures. Pentylentetrazol (PTZ) administration caused the partial reduction of cytochrome oxidase in the brain just before the electroencephalogram (EEG) showed desynchronization, and then blood pressure was elevated concomitantly with an increase in cerebral blood volume. When blood pressure reached a maximum, bursts of spikes appeared on the EEG and cytochrome oxidase was reoxidized to reach the initial oxidation level, giving a rapid, transient reduction of cytochrome oxidase in the preictal period. Hemoglobin was more oxygenated than before the administration throughout the seizure. In the late postictal phase, cytochrome oxidase was partially reduced again, while blood pressure remained high and hemoglobin was more oxygenated than initially. The second administration of PTZ in the late postictal phase induced the same responses as observed after the first administration. By decreasing oxygen concentrations in the inspired gas during the seizure, cytochrome oxidase was more reduced than in the non-epileptic rat, and spike activity was observed until about 85% of cytochrome oxidase was reduced. The transient cerebral hypoxia reflected by the reduction of cytochrome oxidase in the preictal period may be a trigger for an increase in cerebral blood flow rather than the result of a delayed autonomic response. The second reduction of cytochrome oxidase observed in the late postictal phase may be due to a lasting arterio-venous shunt that opens during seizures. These results revive the classical theory that cellular hypoxia is responsible for epileptic brain damage.

Animals↗
PubMed1993

Detection of dynamic changes in cerebral oxygenation coupled to neuronal function during mental work in man.

Changes in the oxygenation state of brain hemoglobin during mental work were monitored in real time (time resolution: 1 s) using near-infrared spectrophotometry in 14 healthy volunteers. In a younger group (age range 22-30 years, n = 12), the subjects finding difficulty in solving a problem were accompanied by significant increases in both oxygenated hemoglobin and total hemoglobin, while the subjects making a correct answer without difficulty showed no significant changes in hemoglobin oxygenation. When compared with those younger subjects, observations on the older subject demonstrated a decrease in oxygenated hemoglobin and a reciprocal increase in deoxygenated hemoglobin, unaccompanied by changes in total hemoglobin.

Adult↗
PubMed1993

Gender- and handedness-related differences of forebrain oxygenation and hemodynamics.

To elucidate gender- and handedness-related differences between the hemispheres of the brain in their metabolisms and hemodynamics, simultaneous monitoring by near-infrared (NIR) spectrophotometry of hemoglobin (Hb) in both hemispheres of the forebrain during the mirror drawing task (MDT) was performed. Bilaterally simultaneous increases of oxygenated Hb and decreases of deoxygenated Hb in forebrain occurred symmetrically in all cases of volunteer subjects except for two. There were gender- and handedness-related differences of hemodynamics between the hemispheres of the brain; NIR results showed that a large majority of women used both sides of the brain when concentrating on carrying out the MDT, whilst most men, especially left-handers, reacted mainly using the hemisphere which was 'dominant' according to handedness.

Adult↗
PubMed1993

Demonstration of sugar moiety on the surface of hepatitis C virions recovered from the circulation of infected humans.

The amino acid sequence for the envelope protein(s) predicted from the nucleotide sequence of the E and E2/NS1 regions of the hepatitis C virus (HCV) genome is enriched with an N-linked glycosylation site motif, Asn-X-Thr/Ser, suggesting oligosaccharide moieties are present on the virion surface. We attempted to characterize the sugar moiety on the surface of HCV virions recovered from sera of infected humans to assess the natural properties of the virus. Six kinds of lectins were used to bind HCV virions in affinity column chromatographies: RCAI, WGA, Con A, AAL, LCA, and PNA. Lectin-bound virions were identified by detecting HCV RNA in eluted chromatography fractions with a polymerase chain reaction (PCR) method. Our results showed that HCV was similar to hepatitis B virus (HBV) in characteristics of binding to lectins: HCV showed a strong binding to RCAI and WGA, weak binding to Con A, and no detectable binding to AAL, LCA, or PNA. Treatment of the HCV virion preparation with an enzyme, glycopeptidase A, or a detergent, NP-40, resulted in a significant decrease in the ability to bind these lectins. Our results suggest that asparagine-linked sugar chains are present on the surface of native virions of HCV, very similar to those for HBV.

Amidohydrolases↗
PubMed1993

Prediction of engraftment after peripheral blood stem cell transplantation by CD34-positive cells in grafts.

A total of 91 peripheral blood stem cell collections were performed in 26 children with various malignant tumors and peripheral blood stem cell transplantations (PBSCT) were performed in 15 of the children. There was a positive correlation between logarithm of total CD34+ cells/kg and logarithm of colony-forming unit-granulocyte macrophage (CFU-GM)/kg (r = 0.86). The time elapsed until the white blood cells (WBC) exceeded 1000/microL was related to both CFU-GM (r = 0.67) and CD34+ cell count (r = 0.60). The number of days elapsed until platelet count exceeded 5 x 10(4)/microL was not related to the logarithm of CFU-GM count/10(5) per kg transfused (r = 0.47), but was related to the logarithm of CD34+ cell counts/10(6) per kg transfused (r = 0.73). The number of days elapsed until the reticulocytes exceeded 10% was not related to the logarithm of CFU-GM count/10(5) per kg (r = 0.52), but was related to the logarithm of CD34+ cell counts/10(6) per kg transfused (r = 0.91). Although CD34+ cell counts correlated with the number of CFU-GM, bone marrow regeneration rates in three lineages were predicted more accurately by the number of CD34+ cells transfused than by the number of CFU-GM. These results suggest that measurement of the CD34+ cell count may be useful in predicting bone marrow regeneration rate after PBSCT.

Adolescent↗
PubMed1993

Chimeric hepatitis B virus core particles with parts or copies of the hepatitis C virus core protein.

Either parts or multiple copies of the core gene of hepatitis C virus (HCV) were fused to the 3' terminus of the hepatitis B virus (HBV) core gene with 34 codons removed. As many as four copies of HCV core protein (720 amino acids) were fused to the carboxy terminus of truncated HBV core protein (149 amino acids) without preventing the assembly of HBV core particles. Chimeric core particles were sandwiched between monoclonal antibody to HBV core and that to HCV core, thereby indicating that antigenic determinants of both HBV and HCV cores were accessible on them. Proteolytic digestion deprived chimeric core particles of the antigenicity for the HCV core without affecting that of the HBV core, confirming the surface exposure of HCV core determinants. The density of HCV core determinants on chimeric core particles increased as copies of fused HCV core protein were increased. Hybrid core particles with multiple HCV core determinants would be instrumental as an antigen probe for detecting class-specific antibodies to the HCV core in patients with acute and chronic hepatitis C and for simultaneous detection of antibodies to HBV core and those to HCV core in donated blood.

Amino Acid Sequence↗
PubMed1993

Oxygen dependence of redox state of copper in cytochrome oxidase in vitro.

To obtain quantitative information about tissue oxygenation from near-infrared signals, the oxygen dependencies of the redox states of both heme a+a3 and copper in cytochrome oxidase of isolated mitochondria were determined at low oxygen concentrations (10(-6)-10(-9) M) using leghemoglobin as an oxygen indicator. The maximum absorbance changes caused by the aerobic-anaerobic transition measured at 830-760 nm of copper in state 3, state 4, and the uncoupled state were 10, 17, and 5% of those at 605-620 nm of heme a+a3, respectively. Thus the relative absorbance ratio of copper to heme a+a3 could be used as a sensitive indicator for the mitochondrial energy state. The oxygen concentrations required for the half-maximal reduction of heme a+a3 varied with the energy state and the respiratory rate and were 7.8 x 10(-8) and 1.6 x 10(-7) M in state 4 and state 3, respectively. In contrast, that of copper was 7.5 x 10(-8) M and was independent of both the energy state and the respiratory rate. The relationship between the percent oxidation of heme a+a3 and copper in the aerobic-anaerobic transition did not show a straight-line relationship. This was referred to as the difference in oxygen affinity between these two chromophores. The deviation from the straight line was larger in state 3 than in state 4.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerobiosis↗
PubMed1993

Dynamic multichannel near-infrared optical imaging of human brain activity.

The present paper demonstrates functional brain mapping with an optical imaging technique by using tissue-transparent near-infrared light. With a maximal five-channel optical monitoring system, we succeeded in detecting region-specific changes in both the hemoglobin oxygenation state and blood volume during various mental tasks, in addition to visual and auditory stimulation. The time course of increases in blood supply varied with each brain region and depended on the type of internal operations occurring during the mental tasks. Changes in the hemoglobin oxygenation state were also different from region to region. This showed that there were regional variations of the oxygen delivery-oxygen utilization relationship during activation of brain activity. The usefulness of multichannel near-infrared functional imaging was well documented.

Acoustic Stimulation↗
PubMed1993

Establishment of a neuroblastoma cell line and induction of lymphokine-activated killer (LAK) activity against the autologous neuroblastoma cell line.

We have established a new human neuroblastoma (NB) cell line from the bone marrow of a 1-year-old boy with NB, termed JK-NB1, which showed constant growth for as long as 17 months or more, similar phenotype to those of other reported NB cell lines, colony formation in liquid and methylcellulose culture, N-myc amplification, high expression of N-CAM, and NSE production. We have tried to induce LAK cell activity with peripheral blood mononuclear cells (PBMCs) from the patient against the autochthonous JK-NB cells. PBMCs from the patient proliferated up to 20-fold in the presence of interleukin-2 (IL-2) after 9 days of incubation, and LAK activity increased up to 24.7-fold and killed all of the JK-NB1 cells. In contrast, IL-2 alone or PBMCs from the patient or a healthy adult donor had little effect on the growth of NB cells. These data suggest that it is possible to induce LAK cell activity in PBMCs from the patient against autologous as well as allogenic NB cells, and provide a rational base for the clinical use of IL-2 as one of the treatments for NB.

Adrenal Gland Neoplasms↗
PubMed1993

Treatment of standard risk acute lymphoblastic leukemia in children with the Tokyo Children Cancer Study Group (TCCSG) L84-11 protocol in Japan.

During the period June 1984 through February 1989, 207 children, newly diagnosed with standard-risk acute lymphoblastic leukemia (ALL), were treated with the Tokyo Children Cancer Study Group L84-11 protocol. The patients were randomized into two regimen groups (S1 and S2). All patients received identical induction therapy with vincristine, prednisolone, and L-asparaginase. For central nervous system (CNS) prophylaxis, the patients in regimen S1 received cranial irradiation (18 Gy) and intrathecal chemotherapy starting at 5 weeks, while those in regimen S2 received this therapy starting at 24 weeks. Consolidation consisted of cyclic therapy with vincristine and dexamethasone, and then, after 128 weeks, with medium-dose methotrexate, CNS chemoprophylaxis, and dexamethasone. Regimen S2 employed early consolidation with three doses of medium-dose methotrexate and CNS chemoprophylaxis. The treatment duration was 3.5 years. Complete remission was achieved in 96.0% and 99.0% of the patients in regimens S1 and S2, respectively. Event-free survival (EFS) rates were 80.0 +/- 3.5% in total, 74.5 +/- 5.7% in regimen S1, and 85.1 +/- 5.7% in regimen S2 at a median follow-up of 42 months (< 85 months). There was no significant difference in the EFS between the two regimens. As compared with recently reported results of treatment for this disease, our protocol can yield similar EFS rates with mild toxicity.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

Cerebral oxygenation state in chemically-induced seizures in the rat--study by near infrared spectrophotometry.

The hemoglobin oxygenation state and the redox state of Cyt.ox. in the rat brain during and after seizure induced by PTZ were measured by using near-infrared spectrophotometry. PTZ administration caused transient reduction of Cyt.ox. in the brain, which might be a trigger for the increase of CBF during seizure. In postictal phase, although BP remained high, Cyt.ox. was in the certain reduced state, which might be due to A-V shunt. Hypoxic loading during seizure caused more reduction of Cyt.ox. than under non-epileptic conditions, which meant that seizure even under mild hypoxic conditions could cause severe hypoxic brain damage.

Animals↗