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Biomedical subjects

K Shimura

Publications and source records attributed to K Shimura.

At least 73 records · Page 4Linked to original sources
PubMed1993

Study on the efficacy of biodegradable poly(L-lactide) mesh for supporting transplanted particulate cancellous bone and marrow: experiment involving subcutaneous implantation in dogs.

Poly(L-lactide) (PLLA) mesh sheets, monofilaments and mesh cylinders filled with fresh autogenic particulate cancellous bone and marrow (PCBM) were implanted subcutaneously into the back of 22 adult dogs for 1 yr. Polypropylene (PP) was used as a control. The inflammatory response to PLLA mesh sheets was slight, similar to PP mesh sheets. However, 3 months after implantation, histiocytes and multinucleate giant cells appeared on the surface of the monofilaments of PLLA mesh sheets and gradually increased in number as the monofilaments were degraded and absorbed. Almost no inflammatory cellular infiltration was seen in the tissue around PLLA mesh sheets or between the monofilaments. When a PLLA mesh cylinder filled with PCBM was implanted subcutaneously, the bone formation reached its peak 1 month after implantation, as in the case of a similar PP mesh cylinder, and bone formation was observed along the inner wall of the cylinder. In addition, a vascular net was abundant within the cylinder. The mechanical strength of the test material (PLLA monofilaments) did not change for almost 2 months after implantation, and 80% of its initial strength was retained for 3 months. These observations suggest that a PCBM graft supported by PLLA mesh would be very effective in the reconstruction of damaged maxillofacial bones, since histological tissue reactions associated with biodegradation of the PLLA mesh are mild and the PLLA mesh does not interfere with bone formation of PCBM. It was also found that the PLLA mesh retains its mechanical strength long enough to allow the PCBM transplant to develop sufficient strength to sustain the damaged region.

Animals↗
PubMed1993

Reduction in tumour formation on porous polyethylene by collagen immobilization.

After surface modification with collagen immobilization through covalent bonding, porous polyethylene pieces with an average pore size of 400 microns were implanted subcutaneously into the back of rats for 1 yr. It was found that connective tissues with abundant blood vessels were formed clearly, filling more than 90% of the pore volume and bound firmly to the pore walls. A tumour was found in only one of 24 implanted pieces (4.2%). On the other hand, the virgin porous polyethylene pieces without collagen immobilization exhibited inflammatory reactions within the pores and the connective tissues produced filled only 15% of the pore volume. Formation of a malignant histiocytoma was observed in 11 of the 24 pieces which had been implanted (45.8%). Thus, immobilization of collagen on the surface of an artificial material through covalent bonding proved to be very effective not only for firm bonding with soft connective tissues but also for a reduction of tumour formation.

Animals↗
PubMed1993

Biochemical and morphological alterations of macrophages and spleen cells produced by antitumor polysaccharide from Acanthopanax obovatus roots.

Acanthopanax obovatus polysaccharide (AOPS) administrated intraperitoneally (i.p.) resulted in the augmentation of phagocytosis and the chemiluminescence in peritoneal macrophages of mice. Binding of the third component of complement (C3) cleavage products to the receptors on peritoneal macrophages was enhanced by AOPS. The C3 conversion in human serum was increased by AOPS in vitro treatment. When given i.p., AOPS led to the enhancement of spleen weight, spleen cell number, and plaque-forming cells. It was also found that after in vivo administration AOPS not only enhanced the synthesis of DNA and protein but also promoted the mitogenic responses of spleen cells. The morphological observation of spleens indicated that AOPS augmented the transformation from lymphocytes to plasma cells. AOPS inhibited the growth of mouse solid Sarcoma-180 and prolonged the survival time significantly. These results suggest that AOPS is an effective biological response modifier and its antitumor activity is related to its immunopotentiating effects.

Animals↗
PubMed1993

Single-exposure dual-energy chest images with computed radiography. Evaluation with simulated pulmonary nodules.

RATIONALE AND OBJECTIVES: Dual-energy subtraction radiography using computed radiography (CR) can aid in the detection of pulmonary abnormalities such as nodules, but the subtracted image requires higher x-ray exposure than usual to reduce quantum mottle. To reduce quantum mottle without increasing x-ray exposure, a new dual-energy subtraction algorithm was investigated that included an edge-adaptive smoothing process and a subtraction process. The signal-to-noise ratio and the image quality of this new subtracted image was significantly superior to that of conventional subtracted images. METHODS: Observer performance of the subtracted digital radiography in detecting simulated pulmonary nodules was compared with original CR images and conventional subtracted digital radiography of 50 patients. RESULTS: A combination of an original CR image and a new subtracted CR image was significantly superior to a single original CR image or a combination of an original CR image and a conventional subtracted CR image (P < .01). DISCUSSION: The single-exposure dual-energy subtraction method is superior to the conventional subtraction method in the detection of pulmonary nodules.

Humans↗
PubMed1993

Antitumor activity of a new low immunosuppressive derivative of podophyllotoxin (GP-11) and its mechanisms.

The spin-labeled derivative of podophyllotoxin, N'-podophyllic acid-N-[3-(2,2,5,5-tetramethyl pyrrolinenyloxy)] semicarbazide (GP-11), was synthesized and tested for its antitumor activity against mouse transplantable tumors, Sarcoma-180, Hepatoma-A, P388 leukemia and Ehrlich ascites carcinoma. At an equitoxic dose, the antitumor activity of GP-11 was similar to that of etoposide (VP-16). However, the immunosuppressive effects of GP-11 were weaker than that of VP-16. In vitro, GP-11 and VP-16 inhibited the proliferation of human lymphoid leukemia Molt 4B cells and suppressed DNA and protein syntheses, but the effect of GP-11 and VP-16 on cell cycle progression was different. The mitotic index was increased by GP-11 and reduced by VP-16. On the basis of flow cytometric bromodeoxyuridine (BrdU)/DNA analysis, GP-11 and VP-16 resulted in the accumulation of cells in the S and G2/M phases. G2/M arrest by GP-11 on cell cycle progression was stronger than that of VP-16, while S arrest was weaker than that of VP-16. After the removal of drugs, the arrest by GP-11 and VP-16 still existed and was irreversible. These results may provide insights into the structure-activity relationships and the design of novel derivatives of podophyllotoxin useful in cancer chemotherapy.

Animals↗
PubMed1992

Antitumor activity of polysaccharide from a Chinese medicinal herb, Acanthopanax giraldii Harms.

The results of experiments with Acanthopanax giraldii polysaccharide (AGP) demonstrated that it inhibited the growth of solid Sarcoma 180 and prolonged the survival time significantly. In tumor-bearing mice, AGP enhanced the phagocytosis and chemiluminescence of macrophages. By the immunofluorescent method, binding of the third component of complement (C3) cleavage product to macrophages and proportion of C3 positive cells were increased. In crossed immunoelectrophoresis, human serum C3 was converted by AGP and appeared as the 3rd peak. The height of the 3rd peak was directly proportional to doses of AGP. The residual CH50 units of human serum decreased dose-dependently. These results suggest that the antitumor activity of AGP is related to the enhancement of immune responses.

Animals↗
PubMed1992

Babesia ovata: isolation from erythrocytes and development of an enzyme-linked immunosorbent assay for detection of antibodies.

A method of isolating Babesia ovata merozoites from infected erythrocytes and an enzyme-linked immunosorbent assay (ELISA) for the detection of anti-B. ovata antibodies were developed. After B. ovata-infected erythrocytes had been lysed using the nitrogen cavitation method, the merozoites were separated from erythrocyte components by differential centrifugation and density-gradient centrifugation. The light microscopic examination showed that the purified merozoites were morphologically intact and contained few contaminants. Sodium dodecyl sulfate-polyacrylamide electrophoretic (SDS-PAGE) analysis revealed that the merozoite fraction contained very little contamination with erythrocyte components. The merozoites thus obtained were sonicated and treated with Triton X-100 and then used as an antigen to measure anti-B. ovata antibodies in ELISA. The ELISA was more sensitive in detecting anti-B. ovata antibodies than was either the indirect fluorescent antibody test or the complement fixation test on sera from cattle infected with B. ovata.

Animals↗
PubMed1992

Diagnostic significance of nuclear DNA content and nuclear area in oral hyperplasia, dysplasia, and carcinoma.

The nuclear DNA content and the nuclear area in hyperplasia, dysplasia, and carcinoma of the oral cavity were quantitatively analyzed by microspectrophotometry. In carcinoma, marked variability of the nuclear DNA content and the nuclear area was found. The mean nuclear DNA content, the variance of the nuclear DNA content, the frequency of cells above tetraploid (4 C), the mean nuclear area, and the variance of nuclear area in hyperplasia and dysplasia were significantly different from these values with carcinoma. In some cases of leukoplakia and verrucous hyperplasia with subsequent malignant formation, the values were beyond the lower limit of carcinoma. The results suggest that the nuclear DNA and the nuclear area are important objective indices for predicting malignant potential of precancerous lesions.

Carcinoma, Squamous Cell↗
PubMed1992

[A 13-week percutaneous toxicity study of prednisolone farnesylate (PNF) gel in beagle dogs with a recovery period of 5 weeks].

The toxicity of Prednisolone farnesylate (PNF) gel, a synthetic glucocorticoid, was investigated in the Beagle dog. PNF gel was administered percutaneously at doses of 0.2, 0.8 and 3.2 mg/kg/day for 13 weeks, then the drug was withdrawn for 5 weeks to evaluate the reversibility. In addition, 2 mg/kg/day prednisolone gel (PN gel), which is approximate to 3.2 mg/kg/day PNF gel in prednisolone molarity, was also administered for comparison. The results are summarized as follows: 1. No deaths were observed in any of the PNF gel test groups or the PN gel group, nor were there any abnormal findings in the clinical signs of the animals. 2. In the hematology, a tendency toward a decrease in the lymphocyte ratio was observed in males from the PNF gel 0.8 mg/kg/day and above groups. In the PN gel group, a significant decrease or a tendency toward a decrease in the lymphocyte ratio was observed, as well as an increase in the white blood cell count in some animals. 3. In the blood biochemistry, a significant decrease or a tendency toward a decrease in total cholesterol and phospholipid was observed in males from the PNF gel 3.2 mg/kg/day group and a tendency toward an increase in triglyceride in females from the PNF gel 3.2 mg/kg/day group was observed. In the PN gel group, a tendency toward an increase in AIP activity, a tendency toward an increase in triglyceride were observed. 4. In the histological examinations, a decrease in the weight of the thymus and adrenal glands, vacuolation of hepatocytes in the middle zone of the liver, atrophy of zona fasciculata of the adrenal glands, hypertrophy of zona glomeruli, swelling of cortical cells of zona faciculate and atrophy of the thymus were observed in the PNF gel 0.8 mg/kg/day and above groups. In the PN gel group, atrophy of submandibular lymph nodes and mesenteric lymph nodes was observed in addition to the same changes as observed in the PNF gel groups. Furthermore, thinning, atrophy or a decrease in the weight of the adrenal glands was also observed both in the PNF gel 3.2 mg/kg/day group and the PN gel group at the end of the 5-week recovery period. 5. As described above, a decrease in the lymphocyte ratio, in the weight of the thymus and adrenal glands and vacuolation of hepatocytes were observed in the PNF gel 0.8 mg/kg/day and above groups.(ABSTRACT TRUNCATED AT 400 WORDS)

Administration, Cutaneous↗
PubMed1992

[A 52-week percutaneous toxicity study of prednisolone farnesylate (PNF) gel in beagle dogs with a recovery period of 8 weeks].

The toxicity of Prednisolone farnesylate (PNF) gel, a synthetic glucocorticoid, was investigated in the Beagle dog. PNF gel was administered percutaneously at doses of 0.05, 0.2 and 0.8 mg/kg/day for 52 weeks, then the drug was with held for 8 weeks to evaluate reversibility. The results are summarized in the following. 1. In the 0.05 mg/kg/day and above groups, hypotrichosis in the application site of the skin, thinning of the skin and atrophy of the appendages, and in the 0.2 mg/kg/day and above groups a tendency toward retarded body weight gain, were observed. 2. In the 0.2 mg/kg/day and above groups, a drop in the lymphocyte ratio, a rise in GOT activity and A1P level, and in the 0.8 mg/kg/day group a rise in free fatty acid were observed. 3. In the 0.2 mg/kg/day group and above groups, atrophy of the zona fasciculata and zona reticularis were observed. In the 0.8 mg/kg/day group, a decrease in the weight of the thymus and adrenal glands, and a increase in the weight of the liver, were observed. 4. At the end of the recovery period, most of the changes disappeared, except for those in the adrenals and treated area. From the above results, under the conditions of this study, it was concluded that when the changes observed in the application site of the skin in each group were not taken into consideration, the toxicological no effect level was 0.05 mg/kg/day for both males and females and the overt toxic dose level was 0.8 mg/kg/day.

Administration, Cutaneous↗
PubMed1991

High-performance affinity chromatography of a chick lectin on an adsorbent based on hydrophilic polymer gel.

A mouse monoclonal antibody (SIA4-5) which reacts with a chick 14K lectin (C14K) was covalently attached to a new support for high-performance affinity chromatography, TSKgel Tresyl-5PW, which is a preactivated, polymer-based particle. The immobilized antibody (SIA4-5-5PW) thus prepared proved to be useful in measuring not only the molecular properties of C14K but also specific interactions of C14K with SIA4-5 and hapten sugars. The C14K preparation was fractionated according to the oligomeric structure and with slight differences in affinity to SIA4-5 although the former was homogeneous in sodium dodecyl sulphate polyacrylamide gel electrophoresis. Application of the method for quantitative analytical purposes was successful.

Adsorption↗
PubMed1991

Immunomodulatory activity of polysaccharide from Acanthopanax obovatus roots.

The effects of the Acanthopanax obovatus polysaccharide (AOPS) as well as its combination with cyclophosphamide (CY) or prednisolone on immune responses were investigated in mice. AOPS (250 mg/kg i.p. x 5) increased the spleen weight and the number of spleen cells, and augmented the phagocytosis of peritoneal macrophages both in normal mice and in immunosuppressed mice. In a haemagglutinin assay AOPS increased the production of specific antibodies and antagonized the suppressive effect of CY. AOPS not only enhanced the degree of in vitro spleen cell-mediated red blood cells (SRBC) hemolysis (quantitative hemolysis of SRBC) but also restored the suppressive effect of CY completely. From these results, AOPS was shown to have an enhancing and a modulating activity on immune responses.

Animals↗
PubMed1990

Tresyl-activated support for high-performance affinity chromatography.

A new activated support TSK gel Tresyl-5PW was evaluated for the coupling of antibodies, which was found to occur easily under mild conditions with high yields. Optimum coupling conditions were a 2-h reaction at 25 degrees C in 1 M phosphate buffer (pH 7.5) when 2-3 mg antibody/ml support is to be coupled and a 6-7-h reaction when ca. 10 mg antibody/ml support is to be coupled. When antibodies were coupled under these conditions, antibody coupling yields greater than 80% and antigen binding efficiencies of 70-80% were achieved, probably owing to a selective attachment of the Fc region of the antibodies. Antigens (human serum proteins) could be separated rapidly without denaturation on antibody-coupled Tresyl-5PW.

Antibodies↗
PubMed1990

Progress in affinophoresis.

The use of polyionic polymers as mobile affinity matrices in electrophoresis has led to the development of a specific separation method for biological substances, affinophoresis. The conjugate of a polyionic polymer and an affinity ligand is called an affinophore. Electrophoresis of proteins in the presence of an affinophore results in a change in the mobility of a specific protein due to the difference between the mobility of the protein and that of the protein-affinophore complex. Polylysine is useful as a base polymer of affinophores and has been used successfully as an anionic matrix after succinylation. Affinophoresis of proteases, lectins and antibodies has been carried out in agarose gel and the mobility of the protein having affinity to each ligand was specifically changed. Two-dimensional affinophoresis, in which an affinophore was included only in the second-dimensional electrophoresis, was effective for the separation of the components of a complex mixture of proteins even if the change of mobility was not large. Red blood cells were successively treated with homologous antiserum, biotinylated second antibody, avidin and biotinylated succinylpolylysine as an affinophore. Specific acceleration of the homologous cells to the antiserum was observed even when the affinophoresis was applied to mixed red blood cells from different species.

Animals↗
PubMed1990

Delayed intermolecular gamma-chain cross-linking by factor XIIIa in fibrinogen Asahi characterized by a gamma-Met-310 to Thr substitution with an N-glycosylated gamma-Asn-308.

In an abnormal fibrinogen with gamma-Met-310 to Thr substitution accompanied by an extra oligosaccharide attached to gamma-Asn-308, factor-XIIIa-mediated intermolecular gamma-dimer formation of fibrin was found to be markedly delayed. The delayed gamma-dimer formation was not due to impaired fibrin polymerization because the fibrinogen gamma-chain also failed to be efficiently cross-linked by factor XIIIa. Since fluorescent amine was normally incorporated into the abnormal gamma-chain by factor XIIIa, we conclude that the abnormal molecules were unable to align their gamma-chains in an anti-parallel fashion because of inaccessibility of the molecules with a profoundly perturbed conformation near the carboxyl terminal region of the gamma-chain included in the D domain.

Fibrinogen↗