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Biomedical subjects

A Shimizu

Publications and source records attributed to A Shimizu.

At least 235 records · Page 13Linked to original sources
PubMed1997

[Influence of the dead space induced by the face mask on the measure of heart rate variability].

The respiratory pattern influences the power spectrum of heart rate variability and therefore control or monitoring of respiration is needed. The effect of the dead space induced by the face mask used in the expiratory gas exchange analysis on the measurement of heart rate variability was evaluated in 22 subjects (15 males and 7 females aged 39-76 years, mean 42 years) using electrocardiography recorded for 5 min during spontaneous respiration under the conditions of supine rest, sitting on the bicycle ergometer with and without a face mask. The power spectrum of heart rate variability was obtained by the coarse-graining spectral analysis (CGSA) method and the total power (TP : 0-0.5 Hz), low frequency component (LF: 0-0.15 Hz), high frequency component (HF: 0.15-0.50 Hz), HF/TP and LF/HF were measured. The volume of the face mask was 320 ml and the tidal volume during sitting with the face mask was 596 +/- 110 ml (444-808 ml). The value of LF/HF increased from supine rest to sitting in accordance to the change of body position (p < 0.05), but the value of LF/HF when sitting with the face mask decreased to the level during supine rest. The value of HF/TP decreased from supine rest to sitting (p < 0.05), but when sitting with the face mask returned to that during supine rest. To evaluate the effect of tidal volume, the subjects were divided into two groups (each of 11 subjects) by the median value of tidal volume (570 ml). The value of LF/HF decreased from supine rest to sitting with the face mask in the smaller tidal volume group (tidal volume < 570 ml) (p < 0.02). Moreover, there was a significant correlation between the change of the value of LF from supine rest to sitting with the face mask and the tidal volume (r = 0.44, p < 0.05). There results suggest that the power spectrum of heart rate variability is strongly influenced by the dead space induced by the face mask used in expiratory gas exchange analysis. In particular, the sympathetic activation from supine rest to sitting in subjects with the smaller tidal volume is unclear. Thus, interpretation of the results of heart rate variability with or without the face mask used in expiratory gas exchange analysis requires care.

Adult↗
PubMed1997

[Successful treatment of hypereosinophilic syndrome with cyclosporin and steroids].

A 41-year-old man with severe hypereosinophilic syndrome was first given a high dose of steroids. His condition improved, and the dose of steroids was tapered. His condition then worsened, and administration of cyclosporin was begun. Disease activity decreased and eosinophil counts decreased to the normal range. Cyclosporin and steroids inhibit the interleukin-2 gene transcription factors NF-AT and AP-1. They also inhibit the interleukin-5 production by peripheral lymphocytes stimulated by interleukin-2. AP-1 is the primary target for steroid-mediated repression of IL-2 gene transcription, but NF-AT appears to be the main target of cyclosporin. In patients with the hypereosinophilic syndrome, cyclosporin can be effective and can minimize the adverse effects of long-lasting therapy with high doses of steroids.

Adult↗
PubMed1997

[Anti-HCV antibody and hemolytic complement activity in sera from alcoholic patients].

We examined the association of complement activation at a low temperature in vitro with hepatitis C virus infection in alcoholic patients. The incidence of cold activation among these patients was 4.1%, which was higher than the reported incidence of 1.7% among general patients consulting a hospital, and that of 0.5% among donors for blood transfusion. In any population, most cases that showed cold activation were HCV antibody positive. The difference between the incidence of cold activation among HCV antibody positive cases in alcohol high consumers (6/21) and that in control patients (42/103) was regarded as nonsignificant. The higher incidence of cold activation among alcoholic patients may not directly associate with high alcohol consumption and may associate with higher incidence of HCV infection among the group.

Alcoholism↗
PubMed1997

Rare glomerular capillary regeneration and subsequent capillary regression with endothelial cell apoptosis in progressive glomerulonephritis.

Glomerulonephritis (GN) leading to glomerular sclerosis remains an important cause of renal failure. The glomerulus is a capillary network, but endothelial and vascular reactions during progressive GN are not well understood. We have, therefore, examined the morphological alterations of glomerular capillary network and endothelial cells during the progression of damaged glomeruli to glomerular sclerosis. A progressive model of anti-glomerular basement membrane (GBM) GN was induced in Wistar-Kyoto (WKY) rats with a single injection of anti-rat GBM antibody. Severe necrotizing glomerular injuries were observed between day 5 and week 3 with a reduction in the number of total glomerular endothelial cells and total glomerular capillary lumina per glomerular cross sections. In necrotizing lesions, the glomerular endothelial cells were lost with the destruction of the glomerular capillary network. Moreover, angiogenic capillary repair with proliferation of endothelial cells was rare in severely damaged regions of glomeruli. Subsequently, mesangial hypercellularity and marked mesangial matrix accumulation occurred with absence of the development of a capillary network, and the necrotizing lesions progressed to sclerotic scars until 8 weeks. Although active necrotizing lesions could not be seen in damaged glomeruli between week 4 and week 8, the number of apoptotic endothelial cells gradually increased in the glomerular capillaries (0.10 +/- 0.01 apoptotic endothelial cells/glomerular cross section at week 8 versus 0.00 +/- 0.00 control cells (mean +/- SEM; P < 0.05) with the progression of glomerular sclerosis. Whereas the number of apoptotic endothelial cells increased in the damaged glomeruli, the number of total glomerular endothelial cells decreased (9.3 +/- 3.0 cells/glomerular cross section at week 8 versus 24.8 +/- 3.0 cells in control (mean +/- SD); P < 0.001) with regression of glomerular capillaries (3.6 +/- 2.5 capillary lumina/glomerular cross section at week 8 versus 35.0 +/- 5.0 capillary lumina in control (mean +/- SD); P < 0.001). Finally, glomerular endothelial cells could not be detected in the sclerotic lesions in progressive anti-GBM GN in WKY rats. These data indicate that the destruction of the capillary network of glomeruli and subsequent incomplete angiogenic capillary repair leads to glomerular sclerosis in progressive GN. Endothelial cell apoptosis with glomerular capillary regression may also contribute to the development of glomerular sclerosis. Injury of the glomerular capillary network with endothelial cell damage, including apoptosis and subsequent incomplete capillary repair, plays an important role in the progression of glomerular sclerosis during anti-GBM GN in WKY rats.

Animals↗
PubMed1997

Comparison of pulsed-field gel electrophoresis and phage typing for discriminating poultry strains of Staphylococcus aureus.

OBJECTIVE: To compare pulsed-field gel electrophoresis (PFGE) patterns of Staphylococcus aureus from chickens in England, Belgium, Bulgaria, Argentina, and Japan, to assess the value of PFGE for discriminating strains, and to compare results obtained by PFGE with those obtained by biotyping and phage typing. SAMPLE POPULATION: 78 S aureus isolates from diseased and healthy chickens. PROCEDURE: Chromosomal DNA of S aureus was digested with restriction endonuclease Sma I, and fragments were separated by PFGE in 1% agarose gel. RESULTS: All 78 strains from 5 countries were classified as poultry ecovar according to a previously established biotyping system. Chromosomal DNA was cut by Sma I into 18 to 23 fragments ranging from about 3 to 685 kb. Seventy-eight strains produced 15 types, arbitrarily designated A to O, and 45 subtypes. Some differences were observed in PFGE patterns among countries. However, 10 fragments (333, 190, 110, 63, 55, 42, 34, 19, 10, and 3 kb) were highly conserved and were shared by almost all (> 78%) of the strains examined. The PFGE patterns were compared with those obtained by phage typing. All 29 strains belonging to avian phage-group II produced type A and 19 subtypes. Of the 15 strains belonging to phage-group I, 11 produced 8 types (B to H, O) and 5 subtypes that were different from those of type A. CONCLUSIONS: Genomic DNA fingerprinting by PFGE is an effective technique for discriminating poultry S aureus strains and appears to be a useful method for subtyping strains of avian phage groups or the poultry-specific ecovar.

Animals↗
PubMed1997

A cell surface antigen that cross-reacts with My4, a monoclonal antibody to CD14, is expressed on human monoblastic cell line U937, B-lymphoma cells, and polymorphonuclear leukocytes.

The CD14 antigen was originally identified on monocytes as a differentiation marker and usually detected by a panel of monoclonal antibodies, including My4 and LeuM3. Recent studies have shown that CD14 antigen is expressed on Langerhans cells, a subject of normal B-lymphocytes, neutrophils, and subtypes of B-cell non-Hodgkin's lymphomas. These antigens, however, react with My4, but not with LeuM3, and the reason for this has not been elucidated. In this study, we found that similar My4+/LeuM3- epitopes are expressed on the human monoblastic cell line, U937. Northern blotting demonstrated that the U937 cells express neither 1.4 kb CD14 transcripts nor possible alternative spliced forms of CD14 transcripts. The molecule was resistant to phosphatidylinositol specific phospholipase C, which effectively hydrolyzes glycosyl-phosphatidylinositol anchored protein, decay accelerating factor, on the same cells. Lipopolysaccharide, which down-regulates the expression of CD14 on monocytes, did not alter the expression of the molecule. We concluded that the My4+/LeuM3- molecule on U937 cells is not CD14 antigen but another surface protein. A similar molecule was also detected on B-lymphoma cells from a patient with non-Hodgkin's lymphoma and on polymorphonuclear leukocytes from healthy donors.

Antibodies, Monoclonal↗
PubMed1996

Tortuosity of the vertebral artery in patients with cervical spondylotic myelopathy. Risk factor for the vertebral artery injury during anterior cervical decompression.

STUDY DESIGN: The case report presented herein shows tortuosity of the vertebral artery in a patient with cervical myelopathy. This case led the authors to evaluate 22 other patients who also had undergone anterior cervical fusion. They were studied before operation by either magnetic resonance imaging angiography or selective vertebral angiography. OBJECTIVES: To analyze the radiographs, computed tomography, magnetic resonance imaging, and angiography findings to detect any tortuosity of the vertebral artery in patients with cervical myelopathy to show the risk factors of vertebral artery injury during anterior decompression. SUMMARY OF BACKGROUND DATA: Complications of vertebral artery laceration during cervical anterior decompression are rare, so this injury and abnormality in the course of vertebral artery in patients with cervical myelopathy receive little attention. METHODS: The tortuosity of the vertebral artery was assessed by angiography, magnetic resonance imaging, and computed tomography. RESULTS: Mild vertebral artery tortuosity was observed in 10 patients and loop formation in three associated with cervical spondylotic changes. CONCLUSIONS: This study suggests that vertebral artery loop formation is developed associated with cervical spondylotic changes. During the anterior decompression of cervical spondylotic myelopathy or radiculopathy, the looped vertebral artery could be injured by an excessive wide rejection of the bone or disc material. In the case of vertebral artery migration, the looped vertebral artery can even be injured by routine procedures.

Adolescent↗
PubMed1996

Mechanisms by which the surface expression of the glycosyl-phosphatidylinositol-anchored complement regulatory proteins decay-accelerating factor (CD55) and CD59 is lost in human leukaemia cell lines.

We have investigated the mechanisms of defects in the glycosyl-phosphatidylinositol (GPI)-anchored complement regulatory proteins delay-accelerating factor (DAF) and/or CD59 in a panel of human leukaemia cell lines that lack surface expression of these proteins: U937 (DAF+/CD59-), CEM (DAF-/CD59+), TALL (DAF-/CD59-) and a substrain of Ramos [Ramos(-)] (DAF-/CD59-). Northern blotting and reverse transcription-PCR revealed that the main cause of the DAF and/or CD59 deficiency is the failure of mRNA expression in most of the cell lines, except in Ramos(-) in which sufficient mRNA for DAF and CD59 was produced. U937, CEM and TALL cells were not defective in GPI anchor formation as assessed by the detection of other GPI-anchored proteins. No gene abnormality corresponding to DAF or CD59 was detected by Southern blotting. Thus the cause of the defects of DAF and/or CD59 in these leukaemia cell lines except for Ramos(-) is virtually undetectable steady-state levels of the relevant mRNA, most likely attributable to lack of transcription in these cell lines. On the other hand, Ramos(-) cells failed to generate a GPI anchor, whereas they normally expressed DAF and CD59 transcripts. The transfection of phosphatidylinositol-glycan class A (PIG-A) cDNA into Ramos(-) cells restored DAF and CD59 expression, indicating that the defective mechanism in GPI anchor formation is similar to that in paroxysmal noctural haemoglobinuria (PNH) cells, i.e. a deficiency of the PIG-A gene product. Thus the mechanisms of the defects of DAF and/or CD59 in human leukaemia cell lines are not uniform, and in most cases are different from that proposed to cause PNH.

Antigens, CD↗
PubMed1996

Activation of lavage lymphocytes in lung injuries caused by radiotherapy for lung cancer.

PURPOSE: Radiation pneumonitis sometimes extends beyond the irradiated area of a lung and can also affect the opposite lung. Some immunological mechanisms, in addition to simple direct injury of the lungs by radiation, seem to be involved in the onset of radiation pneumonitis. To clarify such mechanisms, the effects of radiation on local inflammatory cells in lungs, in particular, lymphocytes, were examined. METHODS AND MATERIALS: A comparison was made of bronchoalveolar lavage fluid (BALF) findings from 13 irradiated patients (RT group) and 15 nonirradiated patients (non-RT group) with lung cancer. Patients who later developed radiation pneumonitis (RP group) and those who did not (RP-free group) were also compared. Using a two-color flowcytometer, radiation-induced changes in local inflammatory cells in lungs were analyzed. This included analyses of human leukocyte-associated antigen (HLADR) and intercellular adhesion molecule-1 (ICAM-1) expression on T-cells, which are though to be involved in cell activation and interactions between cells. RESULTS: The following aspects of BALF were higher in the RT group than in the non-RT group: (a) the percentage of lymphocytes and eosinophiles; (b) the incidence of HLADR-positive CD4+T-cells and HLADR-positive CD8+T-cells; and (c) the incidence of ICAM-1--positive T-cells. The following aspects of BALF were higher in the RP group than in the RP-free group: (a) the total cell counts; (b) the percentage of lymphocytes; and (c) the incidence of ICAM-1-positive T-cells. A significant relationship was seen between the incidence of ICAM-1 expression on T-cells and the number of days from the initiation of radiotherapy to the onset of radiation pneumonitis. CONCLUSION: These data suggest that irradiation can induce accumulation of activated T-cells (HLADR and ICAM-1--positive T-cells) in the lung. This accumulation may be closely linked to radiation-induced lung injury. It is also suggested that the incidence of ICAM-1--positive T-cells in BALF may serve as a useful clinical marker of radiation pneumonitis.

Adult↗
PubMed1996

Transcriptional activation by the androgen receptor in X-linked spinal and bulbar muscular atrophy.

Polyglutamine tracts encoded by trinucleotide CAG repeats have been found in some transcription factors. Expansion of the polyglutamine tracts in the androgen receptor (AR) has been recognized as a cause of X-linked spinal and bulbar muscular atrophy (SBMA). To study the role of AR as a transcription factor in SBMA, we constructed AR genes encoding expanded polyglutamine tracts (repeat numbers = 52, 92, 132, and 212), and analyzed AR-induced transcriptional activation in NG108-15 cells. We found that AR-induced transcriptional activation gradually decreased with increasing glutamine repeat numbers, and polyglutamine expansion caused a specific reduction in transcription activity in motor neurons. However, the degree of reduction was slight in comparison with the normal AR gene and that of SBMA. Thus, subtle disorders of transcriptional control may occur in SBMA.

Animals↗
PubMed1996

Chicken immunoglobulin mu-chain gene: germline organization and tandem repeats characteristic of class switch recombination.

We have isolated the phage clones covering the region spanning from the heavy (H)-chain joining (J) region to the end of the mu-chain gene of the chicken immunoglobulin (Ig). The distance from JH to the first exon of the mu-chain constant (C) region is approximately 13 kb, and introns between the C region exons measure more than 3 kb. These distances are significantly larger than those of known mu-chain genes. We found a region cross-hybridizing to the switch regions of the mouse C mu and C alpha genes just in front of the first exon of C mu. Partial nucleotide sequencing of this region revealed that this region consists of tandem repeats of pentamers (C/T)(C/A)CAG complementary to the mammalian switch repetitive region. These findings suggest that this region is a good candidate for a class switch region of the mu-chain gene of chicken Ig.

Animals↗