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Biomedical subjects

H Kurata

Publications and source records attributed to H Kurata.

At least 109 records · Page 6Linked to original sources
PubMed1994

Vitrification of hematopoietic progenitor cells obtained from human cord blood.

Human cord blood mononuclear cells (MNCs) purified by Ficoll-Hypaque gradient centrifugation were cryopreserved in a vitreous state. The vitrification solution was MEM-alpha medium containing 4-8 mol/l (M) ethylene glycol (EG). A pellet of 1.5-2.0 x 10(6) MNCs was added with 10 microliters of 1 M EG and then 50 microliters of high concentration EG at room temperature (the final concentration was 4-8 M EG). The cell suspension was directly plunged into liquid nitrogen, stored for various periods and rapidly warmed in a water bath at 37 degrees C. The vitrification solution was removed by addition of MEM-alpha medium containing 1 M sucrose. The present experiments demonstrated that a vitrification solution consisting of 8 M EG produced the highest recovery rate for MNCs (89.5 +/- 8.5%), CFU-GM (66.6 +/- 20.8%) and BFU-E (66.5 +/- 22.8%) and the highest Trypan blue viability (98.7 +/- 0.4%). This ultrarapid cryopreservation method may be useful for the preservation of hematopoietic progenitor cells.

Cryopreservation↗
PubMed1994

[Pharmacokinetics of carboplatin in a patient under hemodialysis].

A patient with ovarian cancer under long-term hemodialysis was treated with carboplatin at 240 mg/m2 via intravenous drip infusion for 30 min. Hemodialysis was performed 1 or 2 hrs after the administration of carboplatin. The pharmacokinetics of carboplatin were determined, plasma total and free carboplatin-derived platinum (total Pt and free Pt) levels declined rapidly in the former. The AUC, T1/2 and Cmax of total and free Pt were estimated to be 7.14 and 3.14 mg/ml x min, 35.1 and 18.2 h, and 15.1 and 10.0 micrograms/ml, respectively. Plasma total and free Pt levels showed the same as normal control in the latter. The AUC, T1/2 and Cmax of total and free Pt were estimated to be 8.70 and 5.09 mg/ml x min, 27.6 and 21.9 h, and 13.2 and 13.2 micrograms/ml, respectively. No severe side effect was observed after administration of carboplatin. In conclusion, carboplatin may be given to the patient 2 hrs before hemodialysis in view of the pharmacokinetics.

Carboplatin↗
PubMed1993

Role of the collagen-like domain of the human serum mannan-binding protein in the activation of complement and the secretion of this lectin.

Human mannan-binding protein (MBP) is a C-type serum lectin involved in an immunoglobulin-independent host defense. Recently, a common defect of immune opsonin was found to be associated with very low serum levels of MBP. This deficiency was thought to be an effect of a single base substitution in the MBP gene, which resulted in the conversion of Gly54 to Asp. In this study, three mutant MBPs were expressed in COS-1 cells and the effects of these mutations were studied. Gly54Asp-MBP and Gly57Asp-MBP were secreted into the medium almost at the same levels as the wild type MBP, but the formation of higher multimers and the activation of complement were interfered with significantly. The other mutant, in which Leu was inserted into the Gly63-Gln-Gly sequence to restore the collagen motif of the Gly-Xaa-Yaa repeat, was secreted at levels similar to that of the wild type, formed higher multimers and activated complement in a manner not significantly altered from that of the wild type. These results are discussed with regard to the molecular basis of patients with opsonic defects.

Animals↗
PubMed1993

Automatic evaluation of antifungal volatile compounds on the basis of the dynamic growth process of a single hypha.

An automatic analysing system was developed and employed for the evaluation of antifungal activity of volatile compounds in the gas phase. Aspergillus niger was inoculated on agar medium in the reaction vessel. The reaction vessel was incubated at 28 degrees C for 24 h and then a volatile compound was introduced into the vessel either in a batch or flow manner. The antifungal activity of the respective compounds estimated in situ was expressed by the dynamic response parameters of a single hypha. All volatiles tested in the present system inhibited hyphal growth, except linalyl acetate: Limone and geraniol were the most inhibitory. In contrast, linalyl acetate promoted hyphal growth. By definition of the parameters, the fungicidal and fungistatic effects could be distinguished.

Antifungal Agents↗
PubMed1993

Determination of anti-Aspergillus activity of antifungal agents based on the dynamic growth rate of a single hypha.

The dynamic growth rate of a single hypha of Aspergillus niger was analysed using an automatic system. A colony of A. niger was in contact with saline, saline containing an antifungal agent, and flushing saline, in sequence. The growth rate of a test hypha selected arbitrarily from the colony responded dynamically to the antifungal agent. The minimum concentration that caused the complete inhibition of hyphal growth was defined as the minimum inhibitory concentration (MIC). The MIC values obtained were compared with those determined by conventional methods based on increasing rate of colony diameter or dry matter weight.

Amphotericin B↗
PubMed1993

Effects of antimycotics on the biosynthesis of cellular macromolecules in Aspergillus niger protoplasts.

The effects of nine antimycotics on the biosynthesis of cellular macromolecules were analyzed using the regenerating system of protoplasts of Aspergillus niger. The incorporation of several specific radioactive precursors into major cellular components were measured in the presence or in the absence of respective agents. Miconazole, ketoconazole, and tolnaftate inhibited the lipid synthesis. 5-Fluorocytosine strongly inhibited the DNA and protein syntheses. Griseofulvin, however, specifically inhibited the synthesis of cell wall polysaccharides, i.e. chitin and glucan. Other agents showed non-specific inhibition effects. The significance of morphological change of hypha as an indicator of antimycotic action and its feasibility as a screening tool for novel antimycotic compounds are discussed.

Antifungal Agents↗
PubMed1993

Complete resection of a spinal meningioma extending from the foramen magnum to the second thoracic vertebral body via the anterior approach: case report.

The authors treated a patient with a huge, ventrally located spinal meningioma, extending from the foramen magnum to the second thoracic vertebral body. Vertebral body corpectomies were performed between the bottom of the second cervical vertebral body and the top of the first thoracic vertebral body, and the tumor was completely resected. Neurological symptoms and signs improved postoperatively.

Adult↗
PubMed1993

Studies on the bone marrow cells from an excised pipe bone.

Samples of rib bone were collected and preserved under various conditions. The effect of preserving a piece of bone on the yield of hematopoietic stem cells was analyzed. Bone marrow cells were collected by means of flushing the bone marrow cavity with medium. The initial number of nucleated bone marrow cells collected from the donor's excised rib ranged from 0.8 x 10(8) to 2.3 x 10(8) per 1 cm of rib with an average of 1.21 x 10(8) (n = 7). In addition, the initial number of mononuclear bone marrow cells ranged from 1.1 x 10(7) to 4.8 x 10(7) per 1 cm of rib with an average of 2.47 x 10(7) (n = 7). The percentage loss of mononuclear bone marrow cells from rib preserved in medium for 48 hours at 4 degrees C, was less than 30%. A colony-forming assay by the methylcellulose method, complemented with r-G-CSF, r-GM-CSF, r-IL3, r-IL6, and r-erythropoietin, was done serially using bone marrow buffy-coat cells. These cells were obtained from the pieces of rib that were stored under various conditions. The number of CFU-GM and BFU-E that proliferated in this culture was 41.1 +/- 5.5 and 15.2 +/- 2.7 per dish. If the bone was preserved at 4 degrees C for 48 hours following excision, the recovery of CFU-GM and BFU-E from the bone marrow cells was greater than 50%. The effect of cryopreserving bone marrow mononuclear cells on the yield of hematopoietic cells was also analyzed. The percentage loss of proliferated hematopoietic cells by cryopreservation was less than 30% for bone marrow cells. Bone marrow cells were collected from pieces of rib obtained from cadaveric donors by means of the same method. The average number of nucleated bone marrow cells and MNCs was 1.26 x 10(7) and 2.30 x 10(7) per 1 cm of rib, respectively. The average number of CFU-GM and BFU-E that was detected by the colony-forming assay was 33.4 +/- 5.35 and 11.7 +/- 1.75 per dish, respectively. The percentage loss of proliferated hematopoietic cells by cryopreservation was less than 40% for bone marrow cells from cadaveric donors. These data, which reveal that hematopoietic bone marrow stem cells could be collected from a piece of pipe bone that was without circulation, suggest that it is possible to use pipe bone from cadaveric donors as a source of hematopoietic stem cells for bone marrow transplants.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1993

[A case of endocarditis caused by Candida glabrata].

A 45-year-old diabetic man had aortic valve replacement for Candida glabrata endocarditis. Postoperatively he was treated with fluconazole and amphotericin B. Despite therapy, C. glabrata was isolated from his blood. He collapsed suddenly and died of heart failure 70 days after operation. Autopsy revealed suture line insufficiency and perivalvular leakage. On histologic examination many colonies of fungi were found in the aortic valvular annulus and an embolus to the mesenteric artery.

Aortic Valve↗
PubMed1993

[Treatment of 71 adult acute lymphoblastic leukemia].

From 1975 to 1989, 71 acute lymphoblastic leukemia patients aged 15 to 81 years (median 46 years) were treated at Jichi Medical School. Fifty-eight patients (81.7%) achieved complete remission (CR). Median CR duration was 219 days, and the probability of being in continuous CR at 3 years was 8.9%. Median survival was 462 days, and the probabilities of being alive at 3 and 5 years were 19.8% and 7.3%, respectively. The new regimen introduced from 1987 consisted of remission induction with L-asparaginase, daunomycin, vincristine and prednisolone, followed by intensive consolidation and maintenance. However, the treatment failed to improve outcome. The factor unfavorable for achieving early CR after first-line treatment regimen was the presence of myeloid antigen, and that for achieving final CR after second-line treatment regimen was advanced age. The factors unfavorable for remission duration were high leukocyte count and late CR. Those unfavorable for survival were advanced age and elevated blood urea nitrogen. Further improvement in the design of new protocols which include the use of several cytokines and autologous bone marrow transplantation may result in prolonged disease-free survival.

Adolescent↗
PubMed1992

The 5' untranslated region of the human cellular glutathione peroxidase gene is indispensable for its expression in COS-7 cells.

We studied the expression of the human cellular glutathione peroxidase (GPx) gene, from which a key enzyme containing selenocysteine (Scy) at the active site is produced. Expression of some human GPx gene mutants in COS-7 cells revealed that the 5' untranslated region (utr) was necessary for expression of the GPx gene, since mutant genes having 10 base pairs (bps) at the 5'utr (the complete had 311 bps) expressed GPx at very low levels. The genes with 311 or 408 bps at the 5'utr were better expressed than those having 257 bps. The GPx gene having 133 bps at the 3'utr (80 bps shorter than the entire length) was highly expressed. This deletion did not influence expression. We constructed some mutants in which 3 bases were altered at the upstream region of the Scy UGA codon in the frame of the GPx gene, by site-directed mutagenesis. GPx expression decreased but the expression was restored. Therefore, the upstream region of the in-frame Scy codon was not essential in the Scy decoding mechanisms. Finally, the 5'utr was essential for the expression of GPx gene. However, the deletion of a part of the 3'utr and the site-directed mutation upstream of the Scy codon did not show drastic effects on the expression.

Amino Acid Sequence↗
PubMed1992

[Role of growth hormone in the pathogenesis of dawn phenomenon in IDDM].

The early morning hyperglycemia of diabetic patients has been commonly referred to as the "dawn phenomenon". Recently the nocturnal surges of growth hormone (GH) have been suggested as an important factor in the pathogenesis of the dawn phenomenon. In order to reassess the role of the nocturnal GH secretion in the dawn phenomenon, seven C-peptide negative diabetic patients were studied during 48hr-feedback control using a closed-loop insulin infusion device (Biostator). They received oral sleeping medication only on the first night (control) and sleeping medication with anticholinergic agent (pirenzepine 75mg) on the second night, and blood glucose, insulin requirements, GH and cortisol concentrations during 0000hr and 0700hr were measured. The peak of sleep-induced GH secretions was markedly suppressed by pirenzepine in comparison with the control night (19.8 +/- 3.7 vs. 3.0 +/- 1.2ng/ml; p less than 0.05). Insulin requirements during 0500hr and 0700hr were suppressed significantly by pirenzepine (3.0 +/- 0.2 vs. 2.0 +/- 0.2U/2hr; p less than 0.05). Insulin infusion ratio, i.e. insulin requirements during 0500hr and 0700hr divided by those during 0000hr and 0200hr, was decreased by pirenzepine (2.2 +/- 0.3 vs. 1.5 +/- 0.2; p less than 0.05). There were no significant differences in blood glucose and cortisol concentrations whether or not the anticholinergic agent was given. In conclusion, these results have shown that an anticholinergic agent may be useful in the management of insulin-treated patients with marked dawn phenomenon.

Adult↗
PubMed1992

Some properties of murine selenocysteine synthase.

Selenocysteine (Scy) was synthesized on natural opal suppressor tRNA(Ser) by conversion from seryl-tRNA. We studied the mechanisms of the synthesis of mammalian Scy-tRNA using hydro[75Se]selenide (H75Se-). We found Scy synthase activity in the 105,000 g supernatant of a murine liver extract. The supernatant was chromatographed on DEAE-cellulose, and the activity was eluted at 0.12 M-KCl. The reaction mixture for synthesis of Scy-tRNA contained suppressor tRNA, serine, ATP, seryl-tRNA synthetase (SerRS), HSe- and the enzyme to synthesize Scy-tRNA. These are all essential for the synthesis of Scy-tRNA. Scy in the tRNA product was confirmed by five t.l.c. systems. The conversion from seryl-tRNA to Scy-tRNA was also confirmed with the use of [14C]- and [3H]-serine. The apparent Km values for the substrates serine, tRNA, ATP and HSe- were 30 microM, 140 nM, 2 mM and 40 nM respectively. The active eluates from DEAE-cellulose contained no tRNA kinase. This result showed that Scy-tRNA was not synthesized through phosphoseryl-tRNA. ATP was necessary when Scy-tRNA was synthesized from seryl-tRNA and HSe-. Therefore ATP is used for not only the synthesis of seryl-tRNA but also for the synthesis of Scy-tRNA from seryl-tRNA. The active fraction from DEAE-cellulose was chromatographed on Sephacryl S-300, but the activity disappeared. However, the activity was recovered by mixing the eluates corresponding to proteins of 500 kDa and 20 kDa. In order to examine the binding of HSe- to proteins, a mixture of the active fraction, H75Se- and ATP was analysed by chromatography on Sephacryl S-300. The 75Se radioactivity was found at the position of a 20 kDa protein in the presence of ATP. Thus the 20 kDa protein plays a role in binding HSe- in the presence of ATP. The 500 kDa protein must have a role in the synthesis of Scy-tRNA. There are two natural suppressor serine tRNAs, tRNA(NCA) and tRNA(CmCA), in cell cytosol. The present paper shows that the suppressor tRNA fraction, eluted later on benzoylated DEAE-(BD-)cellulose, is a better substrate with which to synthesize Scy-tRNA. Thus we consider that murine Scy-tRNA is synthesized from a suppressor seryl-tRNA on the 500 kDa protein with the activated HSe-, which is synthesized with ATP on the 20 kDa protein. This mammalian mechanism used to synthesize Scy is similar to that seen in Escherichia coli.

Animals↗
PubMed1992

Automatic antifungal activity analyzing system on the basis of dynamic growth process of a single hypha.

A system for the evaluation of antifungal activity of volatile compounds has been developed that is based on dynamic growth of a single hypha. The newly developed system is composed of a reaction vessel under a microscope, automatic stage, charge coupled device (CCD) camera, TV monitor, video tape recorder (VTR), and a microcomputer. A fungus was inoculated in the reaction vessel containing agar medium and then was treated with an antifungal reagent in the gas phase either in batch or flow reaction manner. The apex of a growing hypha displayed on a TV monitor was followed automatically. From the ratio of the growth rate under exposure of a reagent (UEXPO) to the growth rate before the exposure (UPRE), the antifungal activity was expressed quantitatively.

Antifungal Agents↗
PubMed1992

Evaluation of antifungal activity of antimycotics by automatic analyzing system.

Antifungal activity of several antimycotics has been evaluated using an automatic analyzing system (AAS), which is composed of a specially designed reaction vessel, microscopic observation system, image analyzing system, and computer program for automatic tracing of hypha growth. The agar plate was prepared on the ceiling of the reaction vessel, and spore mass of a fungus (Aspergillus niger) was inoculated onto it. After the preincubation at 28 degrees C for 24 h the reaction vessel was set on a microscope stage and connected to the liquid flow system. An appropriate hypha was selected for the measurement of growth process during the following steps: first contact with saline for 30 min for the adaptation, the second contact with same saline for 30 min, contact with saline containing an antimycotic substance for 60 min, and contact with flushing saline for 60 min. During a sequence of these steps, the apical tip of a growing hypha displayed on a TV monitor was followed automatically. The dynamic response of hypha to an agent was analyzed by several parameters. Morphological changes of the hypha caused by respective agents were recorded on VTR for further analysis. By using this system, the antifungal activity of antimycotics could be quantitatively determined within several hours.

Amphotericin B↗