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Biomedical subjects

A Shimizu

Publications and source records attributed to A Shimizu.

At least 271 records · Page 15Linked to original sources
PubMed1996

A high performance system for molecular dynamics simulation of biomolecules using a special-purpose computer.

GRAPE (GRavity PipE) processors are special purpose computers for simulation of classical particles. The performance of MD-GRAPE, one of the GRAPEs developed for molecular dynamics, was investigated. The effective speed of MD-GRAPE was equivalent to approximately 6 Gflops. The precision of MD-GRAPE was good judging from the acceptable fluctuation of the total energy. Then a software named PEACH (Program for Energetic Analysis of bioCHemical molecules) was developed for molecular dynamics of biomolecules in combination with MD-GRAPE. Molecular dynamics simulation was performed for several protein-solvent systems with different sizes. Simulation of the largest system investigated (27,000 atoms) took only 5 sec/step. Thus, the PEACH-GRAPE system is expected to be useful in accurate and reliable simulation of large biomolecules.

Computational Biology↗
PubMed1995

Patients with ultrasonic coarse-nodular cirrhosis who are anti-hepatitis C virus-positive are at high risk for hepatocellular carcinoma.

BACKGROUND: The relationship between echosonographic patterns of patients with cirrhosis who are antihepatitis C virus (HCV)-positive, the DNA synthesis of hepatocytes, and the risk for HCC were studied. METHODS: Thirty-eight patients with anti-C-100 antibody-positive and Child's grade A posthepatitic cirrhosis were studied. DNA synthesis activity was measured by a bromodeoxyuridine (BrdU, a thymidine analogue)-labeling index (LI), using the BrdU-anti-BrdU in vitro method, and the patients were followed prospectively by frequent liver ultrasonography for 3 years. The ultrasound patterns were classified into fine, coarse, and coarse-nodular (CN) patterns, and the reproducibility of the classification in practical use also was confirmed. RESULTS: Of the 21 patients with high DNA synthesizing cirrhosis (BrdU LI > or = 1.5%), 10 (48%) showed coarse-nodular, 5 (24%) coarse, and 6 (29%) fine pattern in ultrasonography. Conversely, of the 17 patients with low DNA synthesizing LC (BrdU LI < 1.5%), only 1 (6%) showed coarse-nodular, 2 (12%) coarse, and 14 (82%) fine pattern. A significant relationship was found between the two groups of BrdU LI and ultrasound imaging patterns (P < 0.05). The incidence of CN pattern was significantly higher (P < 0.01) in the high DNA synthesizing group than in low DNA synthesizing group. Of the 11 patients with CN pattern by ultrasound imaging, 10 (91%) were in the high DNA synthesizing group, and 9 (82%) developed HCC during the follow-up period, compared with 3 of 7 (43%) with coarse, and only one of 20 (5%) with fine pattern developed HCC. The incidence of HCC was significantly higher (P < 0.01) in patients with a CN cirrhosis pattern than in those with a fine pattern. CONCLUSIONS: In patients with cirrhosis who are anti-HCV-positive, the CN pattern by ultrasound imaging indicates increased DNA synthesis of hepatocytes and a high risk for developing HCC.

Adult↗
PubMed1995

The superreactive disulfide bonds in alpha-lactalbumin and lysozyme.

The disulfide reduction kinetics in equine lysozyme (ELZ), which is a Ca(2+)-binding lysozyme, and human (HLA) and equine alpha-lactalbumin (ELA) at pH 8.5 and 25 degrees C by excess dithiothreitol were studied, and it was found that in ELZ there is no superreactive disulfide bond, while one of the disulfides is reduced very quickly by the reducing agent in HLA and ELA, as in bovine alpha-lactalbumin. The local conformation around the surface disulfide in ELZ seems to be more similar to that in hen egg-white lysozyme than in alpha-lactalbumin. The four disulfides in ELZ were reduced slowly in an apparently single-exponential form, and the bound Ca2+ lowered the reduction rate. The torsion energy on each of the disulfides in three alpha-lactalbumin and eight c-type lysozymes whose native conformations have been experimentally or theoretically analyzed was calculated, and it was found that torsion imposed on the surface disulfide between Cys 6 and Cys 120 in alpha-lactalbumin is a main cause of the superreactivity and all of lysozymes, including the Ca(2+)-binding ones, have no such strained surface bond.

Animals↗
PubMed1995

Apoptosis in the repair process of experimental proliferative glomerulonephritis.

The recovery from the proliferative glomerulonephritis (GN) with reduction of hypercellularity is known in various experimental and human GN. To elucidate the participation of apoptosis in GN, we studied the experimental Thy-1.1 GN for six weeks. Apoptosis was recognized by both light and electron microscopy, and the biochemical expression of apoptosis was morphologically confirmed by in situ end-labeling method of fragmented DNA, using terminal deoxy-transferase. Mesangioproliferative GN was induced by a single administration of anti-Thy-1.1 monoclonal antibody in a rat. Mesangial cell proliferation started early in the process and the number of glomerular cells peaked from day 7 to day 10. Subsequently, the degree of proliferative lesion diminished with obvious reconstruction of the capillary structure, as well as decrease in the number of glomerular cells. During this period, proliferated mesangial cells returned to their original level of cellularity and apoptosis apparently increased in number among the glomeruli. Apoptosis was significantly noted from day 7 to week 4 and was in its maximum at day 10 to week 2. Following this period, by week 6 most of the glomeruli reverted to their original structure. The number of infiltrated neutrophils and macrophages in the glomeruli slowly decreased during the course of the disease, and a few apoptosis were also observed. It is concluded that proliferated glomerular cells regress by apoptosis in the repairing process of GN. Apoptosis plays an essential role in the recovery to the original glomerular structure in GN.

Animals↗
PubMed1995

The association of complement activation at a low temperature with hepatitis C virus infection in comparison with cryoglobulin.

Complement activation at a low temperature in vitro and cryoglobulinaemia are associated with hepatitis C virus (HCV) infection. The frequency of HCV antibody positivity determined in serum specimens that showed the cold-dependent activation of complement was 100%, whereas it was 48% among sera with cryoglobulin. On the other hand, the frequency of cold activation among HCV-infected sera was 41%, and that of cryoglobulin 48%. Cold activation was not found in any HCV- sera studied, whereas cryoglobulin was found at a frequency of 14% in HCV- sera. Cold activation was also absent among hepatitis B virus (HBV) S antigen or antibody-positive sera, except a few that were both HBV+ and HCV+. Rheumatoid factor was also frequently detected in sera with cold activation or cryoglobulin. Cold activation and cryoglobulin may be generated by common mechanisms in which a low avidity, low temperature-preferring antibody may function. In sera with cold activation, fine particles of immune complexes, which do not form precipitates, may activate the complement system. HCV is a unique virus that coexists with antibody in the serum, therefore the avidity of the antibody for the virus antigen may be low, and occasionally react only at a low temperature. This may be why the in vitro phenomenon related to immune complexes occurs specifically in HCV-infected sera.

Cold Temperature↗
PubMed1995

Male genital self-mutilation: a case report.

A review of the literature on self-mutilation of male genitalia and/or auto-castration reveals that they are infrequent and usually related to psychoses or toxic states. In this report the authors present a case of a 17-year-old non-psychotic Japanese male who mutilated his genitalia under clear consciousness because of a conflict over his frequent masturbation.

Adolescent↗
PubMed1995

Effects of aprindine on electrophysiological properties of the atrial muscle in man.

The effects of aprindine on atrial vulnerability were studied in 11 patients; 9 with paroxysmal atrial fibrillation (PAF), and 2 with Wolff-Parkinson-White syndrome, aged 19 to 69 (55.9 +/- 16.5; mean +/- SD). Before and 10 min after the intravenous injection of aprindine (1.5 mg/kg), programmed extrastimulation was performed from the right atrial appendage. Atrial vulnerability was assessed by evaluating the repetitive atrial firing zone (RAFZ), conduction delay zone (CDZ), maximum conduction delay (Max. CD) and fragmented atrial activity zone (FAAZ). After the injection, the duration of the P wave and QTc interval was significantly prolonged without any change in blood pressure or heart rate. RAF was observed in 8 patients under control conditions. However, after the injection of aprindine, the RAFZ completely disappeared in 2 patients, was narrowed in 4, and became wider in 1. AF was induced in the remaining patient. The zone significantly reduced (p < 0.01) without any change in CDZ or Max. CD. While FAA was observed in 5 patients under control conditions, it completely disappeared in 2 patients, was narrowed in 1, and did not change in the remaining 7 after the injection of aprindine. In patients whose RAFZ narrowed after administration of aprindine, the wavelength, as determined from the atrial effective refractory period and conduction velocity, was augmented. These results indicate that aprindine suppresses atrial vulnerability with an augmentation of the wavelength. However aprindine exaggerated atrial vulnerability in some patients, such that atrial fibrillation was induced.

Action Potentials↗
PubMed1995

Herpes simplex virus type 2 infections presenting as brainstem encephalitis and recurrent myelitis.

We describe here 3 patients with central nervous system infection caused by herpes simplex virus type 2 (HSV-2); one patient with brainstem encephalitis and two with recurrent transverse thoracic myelitis. All three patients showed increased IgG antibodies to HSV in the cerebrospinal fluid (CSF). HSV-2 DNA was demonstrated in the CSF by polymerase chain reaction (PCR) amplification. Upon treatment with acyclovir, one patient with myelitis partially recovered and the others completely recovered. It is important to recognize the wide spectrum of clinical manifestations of HSV-2 infection in the central nervous system (CNS).

Adult↗
PubMed1995

Varied effects of thoracic irradiation on peripheral lymphocyte subsets in lung cancer patients.

To investigate the influence of thoracic irradiation on immunological competence in patients with lung cancer, we examined the changes in peripheral blood lymphocyte subsets in 15 patients before and after radiation therapy by two-color flow cytometry techniques. After radiation therapy, the percentage and the absolute number of CD4+CD45RA+ cells (naive T cells) and CD56+ and/or CD16+ cells (NK cells) decreased. The percentage of CD4+human leukocyte antigen-DR(HLA-DR)+ cells (activated CD4T cells) and CD8+HLA-DR+ cells (activated CD8T cells) increased, although the absolute number did not change significantly. Naive T cells may be more selectively damaged than memory T cells by thoracic irradiation, through their recirculation behavior. The reduction of natural killer (NK) cells is disadvantageous for anti-tumor immunity. The percentage of HLA-DR positive T lymphocytes was significantly increased, and thus the possibility of HLA-DR enhancement by irradiation cannot be excluded. Therefore, thoracic irradiation has numerous varied effects on the immunological system of lung cancer patients.

Adult↗
PubMed1995

[Evaluation of the polymerase chain reaction for diagnosis of tuberculous meningitis].

Since Shankar et al used polymerase chain reaction (PCR) for detection of Mycobacterium tuberculosis (M. tuberculosis) in cerebrospinal fluid (CSF), there have been numerous reports on PCR assay for diagnosis of tuberculosis meningitis (TBM). The PCR assay have been recognized to be a rapid method for diagnosis of TBM, however there are problems of PCR sensitivity when dealing with CSF samples containing small amount of M. tuberculosis DNA. Comparing direct PCR with nested PCR, we studied on the evaluation of PCR for diagnosis of TBM. In present study the nested PCR were positive in all CSF specimens from 4 patients with TBM, but we could not detect M. tuberculosis DNA by only the direct PCR. Because nested PCR amplification improved the sensitivity and specificity, the nested PCR assay will be necessary for rapid diagnosis of TBM on the clinical laboratory.

Aged↗
PubMed1995

[Morphologic analysis of blood cells].

Accompanying hematology laboratory automation, the frequency of morphological observation of blood cells tends to decrease. Although 5-part differentials are performed by automated systems, counting of abnormal cells such as immature cells or leukemia cells still must be performed manually using smears. In the automated hematology laboratories, technicians more frequently find abnormal cells than before. Therefore, poor microscopic observation of blood cells markedly affects the diagnosis. Continuous training of the technologist is mandatory. Also, preparation of smear samples is important, i.e, well prepared slides must be stained properly with an appropriate dye. Technicians must be familiar with staining technology together with the knowledge of the characteristics of several staining methods. On the other hand, the technician's ability to differentiate white blood cells depends on the instructor's knowledge. This makes quality control and the standardization of differentials difficult. Still the problems must be solved under the cooperation of the various societies concerned.

Automation↗
PubMed1995

[Quantitative flowcytometric analysis of B cell surface antigens in patients with autoimmune diseases].

In 47 cases of autoimmune diseases (25 SLE, 9 MCTD, 6 PSS, 7 RA), two B cell surface antigens, CD19 and CD20 were quantitatively measured with a flowcytometer. When compared with the results of healthy controls, CD19 antigens were observed to be ca. 10% decreased in SLE and ca. 20% increased in RA. CD20 antigens were observed to be ca. 25% increased in SLE and no changes in RA. No significant increase nor decrease was observed with MCTD and PSS patients. In SLE patients, the amount of CD19 antigen expression was positively related to serum C3 levels, and that of CD20 antigen was negatively related to it. It is not obvious in what mechanism the expression of these antigens are regulated, however, from the point that the expression relates to the amount of serum C3 level, the quantitative measurement of CD19 and CD20 antigens is possibly be a good marker to detect the state of autoimmune disease such as SLE.

Antigens, CD↗
PubMed1995

[Autopsy cases of cytomegalovirus interstitial pneumonitis following bone marrow transplantation].

We investigated the relevance of cytomegalovirus (CMV) to interstitial pneumonitis (IP) using formalin-fixed and paraffin-embedded lung tissues obtained from 12 autopsy cases who died following bone marrow transplantation (BMT) from May 1985 to March in 1992. The lung tissues were examined by hematoxylin and eosin (H.E.) staining, immunohistochemistry with monoclonal antibodies (DDG9, CCH2) and polymerase chain reaction (PCR) for amplifying human CMV DNA. Eight of 12 cases were clinically diagnosed as IP. The 4 cases showed no signs of IP, and their tissues were used as controls. H.E. staining revealed inclusion bodies in two of the eight and only severe fibrosis in the other six. In 4 of the 6 cases, however, CMV was identified by immunohistochemistry or PCR. We concluded that the relevance of CMV in the genesis of IP is often overlooked by H.E. staining alone. Immunohistochemistry and PCR are useful in examining tissues which are suspected of CMV-IP.

Adolescent↗
PubMed1995

[A case report: complete remission of stage IV uterine cervix carcinoma by immuno-chemotherapy with intraarterial infusion using implantable reservoir system].

A patient with neck lymph node metastasis from squamous carcinoma of the uterine cervix was treated by immunotherapy and neo-adjuvant intraarterial infusion chemotherapy (OK-432 ic, etoposide 25 mg/body x 7 days po, CDDP 100 mg/m2/5 hr iA, CPM 200 mg/body iv, THP 50 mg/m2/2 hr iA). Three courses of the neo-adjuvant chemotherapy were given. After the first course, the neck metastatic tumor appeared remarkably small. After the second, the neck tumor disappeared and the uterine tumor appeared small and to have good movement. Hysterectomy was performed one month after. Each tissue platina concentration (microgram/cm3) is 9.12 uterus cervix, 10.9 uterus corporis, 8.17 fallopian tube, 14.0 ovarium, 1.47-0.88 pelvic lymph node. This patient was treated with irradiation after operation, and is presently in a state of cytological complete remission. Now she continues maintenance immunochemotherapy with UFT and OK-432 with a home doctor.

Aged↗