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Biomedical subjects

K Hamano

Publications and source records attributed to K Hamano.

At least 199 records · Page 11Linked to original sources
PubMed1993

Purification of monoclonal antibodies from tissue culture medium depleted of IgG.

A method is described that allows rapid purification of IgG monoclonal antibodies from tissue culture supernatant; it is easy, relatively cheap and produces a product of high purity. Protein G linked to Sepharose fast flow gel has a high capacity for binding IgG and permits large volumes of supernatant to be loaded at high flow rates. However, Protein G cannot discriminate between the monoclonal antibody and other irrelevant IgG e.g. bovine IgG present in the tissue culture supernatant. Therefore, bovine IgG was removed from foetal calf serum by passage over protein G before being used as part of standard tissue culture medium. Hybridomas producing a rat anti-mouse (e.g. KT6) and a mouse anti-mouse (e.g. KJ23a) mAb were cultured in such tissue culture supernatant depleted of bovine IgG. Subsequent passage of the spent culture supernatants over protein G produced good yields of mAb of high purity and concentration. This method can been used to produce many different mAbs without the need for growing cells in a live host as ascites, or the need for specialised tissue culture media or expensive chromatography equipment.

Animals↗
PubMed1993

Shock-reinfusion injury to the central organs and the effect of free radical scavengers in the rat.

Hemorrhagic shock-reinfusion injury produces critical changes in various organs with the generation of oxidant-free radicals. Some papers have reported that shock-reinfusion injury to the intestine is effectively reduced by the scavengers of free radicals; however, few reports mention the central organ damage caused by systemic hemorrhagic shock-reinfusion injury. Using a rat systemic hemorrhagic shock model, injury to the central organs, being the brain, heart, lungs, liver, and kidneys was assessed by measuring malondialdehyde (MDA). The MDA levels in the lungs, kidneys, and liver were elevated significantly after reinfusion, although there was no elevation of MDA in the brain or heart. These data show that the lungs, liver, and kidneys are easily damaged by shock-reinfusion, but that the brain and heart are relatively resistant. The efficacy of the free radical scavengers, superoxide dismutase plus catalase and allopurinol, were evaluated 30 min after reinfusion. Pathological examination showed that superoxide dismutase plus catalase and allopurinol reduced reinfusion injury in the lungs, liver, and kidneys. Moreover, superoxide dismutase plus catalase reduced MDA levels in both the liver and kidneys, whereas allopurinol reduced MDA levels only in the kidneys after reinfusion. However, these free radical scavengers could not suppress the elevation of MDA in the lungs after reinfusion.

Allopurinol↗
PubMed1993

A case of Sturge-Weber syndrome with peculiar venous abnormalities.

A case of Sturge-Weber syndrome with poor filling of the deep cerebral venous system is reported. Usually in this syndrome, enlargement of the internal cerebral, basal Rosenthal, deep medullary, and subependymal veins is revealed by angiography. The abnormality of the deep cerebral venous system in this case corresponded to diffuse faint calcification of the right parietal parenchyma. This was accompanied by venous angioma in the left cerebellar hemisphere and poor filling of the left cerebellar veins-findings which are rare in this syndrome. Occlusion or maldevelopment of the cerebral venous system in the prenatal period may be one possible etiological cause of these venous abnormalities.

Calcinosis↗
PubMed1993

Topographic pattern of the rearrangement of the dystrophin gene in Japanese Duchenne muscular dystrophy.

To compare the frequency and distribution of rearrangements in the dystrophin gene in Duchenne muscular dystrophy (DMD) between Japanese DMD patients and those in North America and Europe, Southern blot analyses of the dystrophin gene were carried out in 88 probands classified as DMD. Gene rearrangements were found in 61 (69%) subjects, and they were composed of partial gene deletions in 53 (60%) probands and partial duplications in 7 (8%) probands. A total deletion of the gene was found in 1 (1%) patient. Among 53 patients with deletions, 34 (64%) had breakpoints between introns 44 and 52 and 7 (13%) had breakpoints between introns 2 and 11. Both the frequency and the distribution of gene rearrangements found in this study were similar to those reported in North America and Europe. These data suggest that there are no ethnic or racial differences in the frequency and distribution of rearrangements thought to be caused by similar mechanisms in the dystrophin gene in all human racial groupings.

Adolescent↗
PubMed1993

A comparative study of linear measurement of the brain and three-dimensional measurement of brain volume using CT scans.

Parameters of linear measurement were compared with actual brain volume to assess the significance of linear measurements as indices of atrophy in 31 neurologically normal children and 22 neurologically abnormal children. Brain volume was established by means of an image-analyzing system using contiguous CT scans. The parameters or indices estimated were: (1) the maximum transverse width of both hemispheres, (2) the maximum longitudinal length of both hemispheres, (3) the maximum frontal subarachnoid space, (4) the maximum width of the interhemispheric fissure, (5) the maximum width of the Sylvian fissure, (6) Evans' ratio, (7) the maximum width of the third ventricle, (8) the cella media index, (9) the maximum width of the fourth ventricle. In neurologically normal children, the maximum transverse width of both hemispheres, the maximum longitudinal length of both hemispheres, the maximum width of the interhemispheric fissure and the maximum width of the Sylvian fissure correlated significantly with the combined volume (CV) of both hemispheres and basal ganglia. In particular, the maximum transverse width of both hemispheres and the maximum longitudinal length of both hemispheres had a high correlation. In neurologically abnormal children the maximum transverse width of both hemispheres and the maximum width of the interhemispheric fissure were significantly correlated with the CV of both hemispheres and basal ganglia.

Adolescent↗
PubMed1993

Self-expanding stainless steel stent application in rectosigmoid stricture.

In recent years, several reports on the experimental and clinical applications of the Gianturco stent (self-expanding stainless steel stent) have been published. However, to our knowledge, the use of stents in rectosigmoid strictures has not been reported. We used self-expanding stainless steel stents to dilate rectosigmoid strictures caused by nonresectable recurrent neoplasm. Insertion and dilation (sigmoid colon and rectum) in two patients were successful. Accordingly, these patients were able to maintain bowel activity and avoid palliative loop colostomy. We believe that this procedure is effective for nonresectable rectosigmoid stricture due to recurrent neoplasm.

Colon, Sigmoid↗
PubMed1993

Cytokines and peripheral tolerance to alloantigen.

The induction of peripheral tolerance to alloantigen is accompanied in many cases by a decrease in the production of cytokines such as IL-2 and IFN gamma, yet a sustained production of cytokines such as IL-10 and IL-4. Whether or not this altered pattern of cytokine production in tolerant animals is causally related to the induction and/or maintenance of the tolerant state has yet to be fully determined, although experiments blocking selectively the action of IL-2 with CD25 antibodies suggest that manipulation of cytokine production may at least be a route to tolerance. Alternative methods for directly influencing the cytokine balance are sought and recent experiments on the CD28/CTLA-4-B7 interaction suggest a possible approach.

Animals↗
PubMed1993

Isolation of trehalamine, the aglycon of trehazolin, from microbial broths and characterization of trehazolin related compounds.

Trehalamine, (3aR,4R,5S,6S,6aS)-2-amino-4-(hydroxymethyl)-3a,5,6,6a- tetrahydro-4H-cyclo-pent[d]oxazole-4,5,6-triol (1) and D-glucose were obtained by acid hydrolysis of trehazolin (3), a trehalase inhibitor produced by actinomycetes. More vigorous hydrolytic treatment of trehazolin afforded an aminocyclitol, (1R,2S,3R,4S,5R)-5-amino-1- (hydroxymethyl)cyclopentane-1,2,3,4-tetraol (2). Trehalamine, the aglycon of trehazolin, was also found in the culture broths of two trehazolin producing strains, Micromonospora sp. SANK 62390 and Amycolatopsis sp. SANK 60791. These trehazolin related compounds trehalamine (1) and 2 were poor inhibitors of trehalase (1; IC50 1.8 x 10(-4) M, 2; > 5.0 x 10(-4) M). On the other hand they inhibited more potently rat intestinal sucrase (1; IC50 6.8 x 10(-5) M) and sweet almond beta-glucosidase (2; IC50 5.6 x 10(-6) M) than trehazolin.

Actinobacteria↗
PubMed1993

Aquastatin A, an inhibitor of mammalian adenosine triphosphatases from Fusarium aquaeductuum. Taxonomy, fermentation, isolation, structure determination and biological properties.

A new inhibitor of mammalian adenosine triphosphatases, designated aquastatin A, has been isolated from a fungus identified as Fusarium aquaeductuum. The structure of this compound has been determined by MS and NMR analyses. It inhibits Na+/K(+)-ATPase with an IC50 value of 7.1 microM, and H+/K(+)-ATPase with an apparent IC50 value of 6.2 microM.

Adenosine Triphosphatases↗
PubMed1993

Efficacy and safety of a quick drying rubbing type povidone-iodine alcoholic disinfectant solution.

The efficacy and safety of a quick drying rubbing type disinfectant (HAD Hand Wash) composed of a povidone-iodine (PVP-I) and ethanol were evaluated in the disinfection of transient skin flora on fingers of 30 medical staff of our department. Three millilitres of HAD solution was rubbed onto the hands for three minutes several times a day over a four week period. Bacteriological effects were evaluated twice, on the first day and after four weeks, by the palm stamp method. The rate of colonies sterilized (bacterial reduction rate) after the use of HAD Hand Wash was 86.9 +/- 21.2% (mean +/- SD) on the first measurement, and 91.5% +/- 12.8% at four weeks. Staphylococcus epidermidis was isolated most frequently and this was eradicated in 83.3% of subjects, the bacterial reduction rate 99.7%. Staphylococcus aureus was originally isolated in 14 subjects and was eradicated in 13; the bacterial colony reduction rate was 99.9% showing high antiseptic efficacy. Although the bacterial reduction rate for Bacillus sp. was a rather low, 75.8-100%, this result was not considered problematic from the clinical standpoint. There were no side effects like chapping in spite of an average 104 applications of HAD Hand Wash during the 4-week test period. From these results, HAD Hand Wash was considered highly effective and safe.

Antisepsis↗
PubMed1993

[A case report of surgically treated tracheobrachiocephalic artery fistula following tracheostomy].

The patient was a 17 year-old-boy with mental retardation and cerebral palsy, who underwent tracheostomy because of tracheobronchomalacia and tongue swallowing three months ago. After minimal tracheostomy bleeding was noted for a few days, massive hemorrhage occurred suddenly. The patient was severely hypotensive. The cuff on the tracheostomy tube was hyperinflated, which stopped the bleeding temporarily. Through a median sternotomy and collar incision, a pin hole-sized defect in the medial surface of the brachiocephalic artery at the tracheal balloon was repaired by suture. The tracheal defect allowed visualization of the tracheal cannula balloon. The pectoralis major muscle flap was interposed between the tracheal defect and the artery. The tracheal defect was packed with muscle. Seven days after the operation, the second operation was done for recurrent bleeding. The defective segment of brachiocephalic artery was resected and the ends were oversewn with monofilament sutures. Continuous irrigation with povidone-iodine solution was continued for purulent mediastinitis. We believe that interruption of blood flow of the brachiocephalic artery, interposition and packing of muscle flap over the tracheal defect and continuous irrigation for infection were effective treatment of choice.

Adolescent↗
PubMed1993

[Influences of 5'-deoxy-5-fluorouridine (5'-DFUR) on cell cycle in patients with breast cancer].

Recently, the effectiveness of preoperative chemotherapy for cancer treatment has attracted much attention. The authors conducted a study to investigate the influence of 5'-DFUR administration on the cell cycle, based on DNA analysis using FCM in patients with breast cancer. A total of 53 patients with breast cancer (Stages I, II and III) were investigated concerning tumor PyNPase activity and cell cycle phase. Subjects were stratified according to tumor diameter, histologic type and ER in the group receiving preoperative 5'-DFUR administration (25 patients) and the group not receiving 5'-DFUR (28 patients). The subjects in the group on 5'-DFUR preoperative administration were classified into three sub-groups according to total dosages of 400 mg (8 patients), under 4,800 mg (8 patients) and 4,800 mg or over (9 patients). In terms of tumor diameter, significant increases (p = 0.027) of S-phase were observed in patients with the diameters of 5 cm or more in the sub-group of under 4,800 mg dosage. Similar tendencies were seen in all drug administration groups (p = 0.05). However, no influence was observed on S-phase in the group without 5'-DFUR administration. In terms of ER stratification, ER(-) patients in the dosing groups showed increasing tendencies in S-phase and significant differences of G1- as well as G2+M phases. No differences in PyNPase activity were noted in each stratified group. Preoperative administration of 5'-DFUR resulted in alterations of cell cycle in breast cancers. In patients with a total drug dosage of under 4,800 mg and with tumor diameters of 5 cm or more, increases of S-phase and decreases of G1-phase were observed. It was suggested that 5'-DFUR acted in DNA synthesizing stage to accumulate S-phase inhibiting cell cycles. Consequently, this drug is considered useful for neoadjuvant chemotherapy.

Antineoplastic Agents↗
PubMed1992

Epitope mapping of anti-recA protein IgGs by region specified polymerase chain reaction mutagenesis.

Monoclonal IgGs were shown to be useful for the specific inhibition of a set of activities of the recA protein, a key protein in homologous genetic recombination. The mapping of the epitopes for these IgGs and site-directed mutagenesis based on the mapping will facilitate location of the functionally active sites on the tertiary structure of the protein, which is being solved by means of physicochemical techniques. We developed a novel technique for region-specified mutagenesis and applied the technique to epitope mapping. Using the polymerase chain reaction in the presence of deoxyinosine triphosphate, we introduced random base substitutions specifically into a region of the recA gene defined by a pair of primers. RecA mutants exhibiting altered antigenicity were selected, in plaque-immunoblotting experiments, from libraries of mutagenized recA genes constructed on the lambda gt11 expression vector. Mutant recA genes were obtained at the frequency of about 10(-2) among the plaques expressing fused recA genes and then each one was expressed as a whole protein, which was characterized by enzyme-linked immunosorbent assay. Analyzing the DNA sequences of the mutant recA genes, we located at the amino acid sequence level the epitopes for two anti-recA IgGs which could not be located in previous studies. One of the antibodies was shown to prevent self-assembly of the recA protein and the other was suggested to inhibit the binding of double-stranded DNA. Thus, the active sites involved in these functions would be located in the space around or near the relevant epitope.

Amino Acid Sequence↗