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Biomedical subjects

S Sekiguchi

Publications and source records attributed to S Sekiguchi.

At least 163 records · Page 9Linked to original sources
PubMed1991

The particle size of hepatitis C virus estimated by filtration through microporous regenerated cellulose fibre.

To estimate the particle size of hepatitis C virus (HCV), a major causative agent of post-transfusion non-A, non-B hepatitis, we filtered plasma or serum samples through microporous cellulose fibres with different pore sizes. The amount of HCV particles in samples before and after filtration was determined by a quantitative reverse transcriptase polymerase chain reaction (PCR) method. Since there is no quantitative biological assay for HCV, except for that in chimpanzees, the HCV titre obtained from the PCR method was used in an equation constructed previously for application to filtration experiments with a flavivirus which is distantly related to HCV. The particle was estimated to be between 30 and 38 nm in diameter, although the possibility remained that larger HCV particles or HCV aggregates with a diameter of more than 39 nm might exist. Double-step filtration through microporous cellulose fibres with a pore size of 35 nm reduced the HCV content to below levels detectable by our PCR method, indicating that it is possible to eliminate HCV particles by simple filtration techniques.

Base Sequence↗
PubMed1991

Antitumor efficacy of doxorubicin in combination with cisplatin on human lymphoma cells at various cell densities in vitro.

The influence of tumor cell density on the antitumor effect of doxorubicin (DXR) in combination with cisplatin (CDDP) was studied in vitro using DND-39A lymphoma cells. DXR was progressively less effective on colony formation inhibition when cell density was increased from 10(5) to 10(8) viable cells/ml (positive inoculum effect), whereas the effect of CDDP was not influenced by cell densities. At a density of 10(5) cells/ml, inhibition of colony formation was virtually identical irrespective of cells being exposed to DXR and CDDP either simultaneously or sequentially. When cell density was increased to 10(7) and 10(8) cells/ml, sequential exposure to CDDP followed by DXR was more active than simultaneous or reversed order of exposure to the two drugs. These results indicate that for DXR-CDDP combination chemotherapy against the cells at high density, the proper sequence of the treatment should be the administration of CDDP followed by DXR, rather than simultaneous or reversed order of exposure. Inoculum effect may be an additional determinant for the rational development of combination chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

[Clinical diagnosis and laboratory data].

Modern medicine can not be practiced without laboratory tests. Laboratory tests play a vital role from the initial stage of clinical examination. The Japanese Society of Clinical Pathology has formed a committee specifically dealing with the effective and economic use of lab tests without missing or duplicating the important tests. As is shown in table 1 in the main text "Essential Laboratory Tests" were initially agreed as those tests a patient should take when visiting a clinic regardless of the complaint. From an early stage, laboratory tests were done simultaneously with history-taking and physical examinations. Then the "Initial Impression" is obtained and "Organ-oriented 1st and 2nd screening tests" and confirmatory tests will be done to make the final diagnosis. To evaluate the validity of the "Essential Laboratory Tests", we performed the tests on 1026 patients who visited our general medicine clinic for the first time. We compared the Initial Impression with or without Essential Laboratory Tests. Cases in which a diagnosis could not be made by history-taking and physical examination were decreased from 17.4% to 8.0% by performing the essential laboratory tests. Diagnoses made without the essential laboratory tests were found to be mistaken in 10.4% and the additional use of the tests was suggested to lead to a more accurate diagnosis. In 110 cases, diseases unrelated to the chief complaints, were discovered. Even for the respiratory tract infection, CRP and WBC count, which were included in the essential laboratory tests, were very informative.

Adolescent↗
PubMed1991

[Evaluation of treatment of lung cancer combined with the disease which has needed a semi-emergency operation].

Six cases of lung cancer combined with the disease which has needed semi-emergency operation, two cases of unstable angina, two of ileus due to colon cancer, one of impending rupture of abdominal aortic aneurysm and one of purulent cholecystitis with cholelithiasis, were discussed. Mean age was 62.0 years (range, 36 to 73); four were male and two were female. Case 1 and 2 were admitted with anterior chest pain, Case 3 with lumbago and abdominal pain, Case 4 and 5 with an abnormal shadow on chest x-ray film and Case 6 with abdominal pain. Of the two with unstable angina, one was operated on with right upper lobectomy during the first months after aorto-coronary bypass. Of the two with colon cancer, one was operated on with right upper lobectomy during about 5 weeks after right hemi-colectomy. Case 3 with abdominal aortic aneurysm operated on with left upper lobectomy during 4 weeks after replacement of abdominal aorta. Case 4 with cholecystitis was operated on with left pneumonectomy during about 3 weeks after cholecystectomy. The postoperative course of 4 cases and the post-chemotherapy condition of 2 cases were uneventful.

Adenocarcinoma↗
PubMed1991

[A surgically treated case with lung cancer on maintenance hemodialysis].

Maintenance hemodialysis for chronic renal failure has spread all over the country, and the number of patients in whom surgical indications are considered to concomitant diseases has been increasing. A 76-year-old male was admitted due to lung cancer on maintenance hemodialysis. The chest roentgenogram showed a 2.5 cm sized coin lesion in the right middle lung field. Preoperative examinations, chest tomography, chest CT-scanning, bone scintigraphy, bronchofiberscopic biopsy, etc. led to a diagnosis of primary lung cancer (squamous cell carcinoma). Hemodialysis with prescribing nafamostat mesilate (40 mg/hour) was performed the day before the operation and on the first, fourth and sixth postoperative days. There was no postoperative bleeding. The patient has been well for 27 months postoperatively.

Aged↗
PubMed1991

[Organ transplantation and laboratory tests].

The media has recently been featuring organ transplantation from various viewpoints. Furthermore, Novel Prizes 1990 for Medical & Physiological fields were awarded to Drs. JE Murray and ED Thomas, both pioneers of clinical transplantation. Our topic has been timely indeed. This symposium mainly dealt with laboratory tests vs. various types of organ transplantation. In reality though, only kidney and bone marrow transplantations have been practiced in Japan; thus, Dr. I Yokoyama, University of Pittsburgh, discussed liver transplantation. First, Dr. K Uchida lectured on the recent advancement of immunosuppressive drugs and improvement in the clinical outcome of kidney transplantation. Serum creatinine determination is the only parameter for rejection besides renal biopsy. Drs. K Miyamura & Y Morishima discussed about PCR method to detect MRD (minimal residual diseases). There are positive relationships between the remaining leukemic cells and the relapse of leukemia even though the patients are in clinical remission. Dr. H Funada dealt with the importance of "sterile room treatment" for bone marrow transplantation. It protects patients from infection, minimizes GVHD and prolongs survival time after transplantation. Dr. Yokoyama stressed the importance of back-up system, i.e. drug-monitoring, coagulation tests, pathological examination, biochemical tests, blood transfusion services for successful liver transplantations. Dr. T Fukunishi discussed the importance of developing the organ donor and coordinator system to promote kidney transplantation from cadaver. He also dealt with virus antibody tests for selecting donors. All discusssions stressed on the importance of the 24-hour laboratory back-up system performing emergency tests but no specific laboratory test for organ transplantation was necessary.

Clinical Laboratory Techniques↗
PubMed1990

A platelet membrane glycoprotein (GP) deficiency in healthy blood donors: Naka- platelets lack detectable GPIV (CD36).

It has recently been shown that the Naka antigen, which is absent in 3% to 11% of Japanese blood donors, is expressed on platelet glycoprotein IV (GPIV; CD36) (Tomiyama et al, BLOOD, 75:684, 1990). In the present studies, flow cytometry was used to distinguish differences in the reactivity of Naka+ and Naka- platelets with both OKM5, a monoclonal antibody that recognizes an epitope on GPIV, and with polyclonal anti-GPIV antibody. OKM5 was also used to screen 871 platelet concentrates prepared from healthy US blood donors. Three of these showed markedly deficient binding of 125I-OKM5 or an incidence of 0.34%. Two of these donors were re-accessed and showed less than 1% binding of 125I-OKM5 as compared with 10,300 +/- 1,500 binding sites per platelet in controls (n = 4). Platelets from these two US donors were radiolabeled (125I, 3H) and compared with control platelets and with platelets from Japanese Naka+ and Naka- donors by crossed immunoelectrophoresis, protein blots, immunoprecipitation, and two-dimensional gel electrophoresis. GPIV could not be detected by any of these techniques in the Naka- platelets nor in the donors whose platelets showed deficient binding of OKM5. These results suggest that GPIV functions as an isoantigen rather than an alloantigen in immunizing Naka- platelet recipients. This is the first report of the absence of a major platelet membrane GP in healthy blood donors.

Antibodies, Monoclonal↗
PubMed1990

A cDNA clone closely associated with non-A, non-B hepatitis.

A lambda gt11 cDNA library was constructed from RNA purified from hepatitis B viral surface antigen-negative human plasma with high alanine aminotransferase activity. A cDNA clone, designated as C8-2, was isolated by immunoscreening with mixed sera from non-A, non-B hepatitis (NANBH) carrier and convalescent chimpanzees. The recombinant protein produced by C8-2 reacted specifically with sera of patients in the chronic phase of NANBH. The sequence of C8-2, 269 bp, did not hybridized with any human or chimpanzee genomic DNA, and had no homology with those of primates and viruses. The existence of this sequence in RNA of possibly infectious plasma was shown by RNA blot hybridization and by Southern blot analysis of products amplified by the polymerase chain reaction. These results strongly suggest that C8-2 is derived from the agent of this viral hepatitis.

Amino Acid Sequence↗
PubMed1990

Identification of the platelet-specific alloantigen, Naka, on platelet membrane glycoprotein IV.

We describe the membrane localization of a new platelet-specific alloantigen, designated Naka, that is involved in refractoriness to HLA-matched platelet transfusions. By indirect immunoprecipitation, anti-Naka antibody precipitated a single, radiolabeled platelet membrane protein with a molecular weight (mol wt) of 91 Kd from Naka-positive platelets. When radiolabeled Naka-negative platelets were used as a source of target antigens, no radiolabeled proteins were precipitated. The analyses using nonreduced-reduced two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and using rabbit antiglycoprotein (GP)IV demonstrated that this protein corresponds to GPIV (alternatively GPIIIb). Furthermore, in dot immunobinding, anti-Naka antibody bound to purified GPIV. Our results provide definitive evidence that the Naka alloantigen is carried on GPIV. These results also demonstrate that, on occasion, antibodies against GPIV may play an important role in refractoriness to platelet transfusions.

Antigens, Surface↗
PubMed1990

Production of interleukin 1 from human monocytes stimulated by synthetic lipid A subunit analogues.

We have investigated that synthetic lipid A subunit analogues (GLA compounds) as well as E. coli type lipopolysaccharide (LPS) and synthetic lipid A (compound 506) are able to stimulate human monocytes to release IL-1 in vitro. Of monosaccharide-type GLA compounds, GLA-60 was found to be more active for the induction of IL-1 production than GLA-59 and GLA-27, and similar to that of LPS or compound 506. GLA-60 could induce not only the secretion of IL-1 into culture supernatant but also the expression of membrane-associated form of IL-1 in human monocytes. Furthermore, no detectable IL-2 activity was observed in the culture supernatant. These results show that synthetic lipid A analogues of low toxicity, in particular GLA-60, are active in inducing IL-1 production in human monocytes.

Cell Division↗
PubMed1990

Associations between restriction fragment length polymorphisms detected with a probe for human C4 and allotype of C4B5 allele.

We studied the fourth component of human complement (C4) allotypes in 58 Japanese individuals. The technique of Southern, with C4 and 21-OH cDNA probes, was used to examine the genomic DNA of 45 individuals typed for C4 by protein electrophoresis. Novel HindIII C4 10- and 5-kb and EcoRI C4 13-Kb restriction fragments were identified in each of nine Japanese individuals. The novel fragments were different from the previously described C4B long (HindIII 31-kb, TaqI 6-kb, BamHI 4.3-kb, and EcoRI 12-kb) and C4B short (HindIII 25-kb, TaqI 5.4-kb, BamHI 3.5-kb, and EcoRI 15-kb) fragments. All novel HindIII- and EcoRI-positive individuals carried C4B5, BfS, and HLA-Bw54. Therefore, the fragments were characteristic for the C4B5 allele. The C4 region was analyzed to determine the restriction sites by single and double digests of uncloned genomic DNA with several restriction endonucleases. It is speculated that an insertion gene lies between the 3' end of the 21-OH and the 5' end of the C4B genes.

Adult↗
PubMed1990

Activation by synthetic lipid A subunit analogues (GLA compounds) of tumoricidal properties in human blood monocytes.

The authors have determined that synthetic lipid A subunit analogues (GLA compounds), as well as E. coli type lipopolysaccharide (LPS) and synthetic lipid A (compound 506), are able to stimulate human monocytes to become cytotoxic against tumour target cells in vitro. GLA-60, a synthetic lipid A subunit analogue of low toxicity, was found to be more active for the induction of tumoricidal monocytes than GLA-59, and similar to that of LPS. GLA-60 could induce not only the secretion of cytotoxic factor into the culture supernatant but also expression of the membrane-associated form of cytotoxic factor in human monocytes. Supernatant-mediated cytotoxicity was completely inhibited by the addition of monoclonal anti-human TNF antibody. These results indicate that a synthetic lipid A subunit analogue, GLA-60, would be a useful activator of tumoricidal monocytes in spite of its low toxicity.

Adjuvants, Immunologic↗
PubMed1990

An attempt to prepare hepatitis B virus (HBV)-free plasma by ultrafiltration using microporous regenerated cellulose hollow fiber.

Hepatitis B virus (HBV) can be effectively removed from HBV-positive plasma by filtration with a Bemberg Microporous Membrane (BMM) with a pore size of 30 nm or less, however considerable amounts of macromolecular IgM and Factor VIII are trapped in the BMM. We report that HBV-free plasma with adequate amounts of all of the plasma proteins can be obtained by double filtration with a BMM with a port size of 50 nm. Thus it may be possible to remove HBV or other transfusion-associated viruses from plasma by BMM filtration with good recovery of all of the plasma components.

Blood Proteins↗
PubMed1990

HLA-DR, DQ and T cell antigen receptor constant beta genes in Japanese patients with ulcerative colitis.

We studied the T cell antigen receptor (TcR) constant beta chain genes on HLA typed Japanese patients with ulcerative colitis (UC). A TcR constant beta EcoRI 6.0-kb fragment was present in all Japanese UC patients (n = 17) but completely absent in the controls (n = 35) (chi2 = 47.6, P less than 0.001). The frequency of HLA-DR2 antigen was significantly higher in UC patients (85% versus 28% in controls, P less than 0.001). Furthermore, HLA-DQw1 antigen was also increased in UC patients (96% versus 60% in controls, P less than 0.001). However, HLA-DR4 antigen was significantly decreased in UC patients (12% versus 37%, P = 0.02). HLA-DR1 antigen was not found in UC patients and was present in only 15% of the controls. These results suggest that TcR beta chain and HLA-DQw1 antigen may be important in the pathogenesis of Japanese UC.

Adolescent↗
PubMed1990

A new type of blood component collector: plasma separation using gravity without any electrical devices.

A new type of blood component collector (BCC) was developed to divide 450 ml of whole blood into plasma and a red cell concentrate using gravity without electrical devices. This BCC system is composed of one whole blood collection bag, two product collection bags and a plasma separator, which consists of a bundle of hydrophilized polyethylene hollow fibers (0.2 micron pore size). Without rinsing the plasma separator, the whole blood (458.1 +/- 13.5 ml, n = 22) was run through the separator using gravity without a pump. An average of 175.9 ml of plasma was collected within 11 min without hemolysis. In this completely cell-free plasma, the recovery of total protein, albumin, globulin, IgG and IgA was nearly 100%. Prothrombin time and activated partial thromboplastin time were in a normal range and the activity of coagulation factors did not change after the separation. In the red cell concentrate, the recovery of red cells, white cells and platelets was 94.7, 98.4 and 82.7%, respectively. Osmotic fragility of red cells, platelet morphology and functions did not change. These observations suggest that this new type of BCC is useful as a simple, fast and safe component collector.

Blood Platelets↗
PubMed1990

Bovine albumin-like protein in commercial human albumin for clinical use.

We have demonstrated that several lots of commercial human serum albumin (HSA), prepared for clinical use by two manufacturers, reacted with anti-bovine whole serum in the double-diffusion test. The antigenic proteins were purified by affinity chromatography from these HSA lots and their chemical and immunological properties characterized. The purified proteins showed the same molecular weight as HSA and bovine serum albumin (BSA). By CNBr treatment and trypsin digestion, the purified protein produced the same fragments as BSA. Moreover, the purified protein had an amino acid composition very similar to BSA and also 30 residues identical to those of the N-terminal amino acid sequence of BSA. In addition, it was shown that heterophilic Hanganutziu-Deicher antigenicity was present in the purified protein. The protein reactive against-bovine whole serum, contained in commercial HSA, was called BSA-like protein.

Amino Acid Sequence↗