Measles outbreak in a junior high school in November-December 1998.
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Biomedical subjects
Publications and source records attributed to M Tashiro.
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UNLABELLED: PET with three-dimensional data acquisition using 18F-fluorodeoxyglucose (FDG) was applied to evaluate skeletal muscle activity in runners. METHODS: Seven healthy adult male volunteers were studied. They ran for a total of 35 min, 15 min before and 20 min after intravenous injection of FDG. Another 7 adult male control subjects were also examined at rest. Images obtained through a set of whole-body PET scans were analyzed. Regions of interest (ROIs) were manually drawn on images of muscles of both thighs, legs and feet, and the standardized uptake ratio (SUR) and total radioactivity distribution (TRD) for each region were calculated. RESULTS: The work load was below the anaerobic threshold. SUR of foot, leg and thigh were low at rest but during running increased 5.19, 4.30 and 1.74 times, respectively. The SUR of posterior-to- anterior compartment of the leg was 1.1+/-0.1 at rest and 1.6+/-0.5 (P < 0.01) during running. The laterality index of both SUR and TRD changed significantly only in the foot of the dominant side during running. TRD of the leg, less than half that of the thigh at rest, became equivalent to that of the thigh during running. TRD of the foot did not change significantly. CONCLUSION: Sole muscles showed highest metabolic activation per unit volume during running, which was higher in the dominant side. Comparison of whole muscle activity during running indicated the highest metabolic activation was in the posterior compartment of the leg, whereas thigh muscles showed relatively little changes during running. Our data indicate that whole-body FDG PET, especially three-dimensional data acquisition, is a useful tool for the investigation of muscular activity during exercise.
Second and third domains were prepared from Japanese quail ovomucoid and association equilibrium constants, Kas, were measured at 25 degreesC and pH 8 for these domains with trypsins from ten mammalian species: cat, cow, dog, guinea pig, hog, horse, man, rabbit, rat, and sheep. The values ranged from 108 M-1 to 1010 M-1 for the second domain-trypsin associations and from 106 M-1 to 108 M-1 for the third domain-trypsin associations. Changes in Ka values for the interactions between the trypsins and each domain are attributed to slight changes in surface conformation caused by the residue changes in the inhibitor-binding region other than the S1 pocket of the trypsin species. The representative of such residue changes is assumed to be the one observed at residue 217 of trypsin molecule. Concerning each trypsin, the Ka value with the second domain was always higher than that with the third domain. However, the ratios between the two equilibrium constants varied from 3 to 60 depending upon trypsin species. This means that amino acid changes in enzyme-contact residues other than the P1 site of the Kazal-type inhibitor can make it possible to recognize even a slight difference in inhibitor-binding surface among the enzymes with the same S1 pocket and highly similar overall three-dimensional structure.
The Nef protein of HIV-1 binds to and induces apoptotic cytolysis of uninfected but activated human peripheral blood mononuclear cells (PBMC) and various cell line cells derived from CD4+ T, CD8+ T and B lymphocytes, macrophages, and neutrophils. The Nef-induced apoptosis also occurs with blood cells not expressing CD95 (Fas). The Nef-induced apoptosis as well as Fas-mediated apoptosis was inhibited by acetyl-Try-Val-Ala-Asp-CHO, an IL-1beta converting enzyme (ICE) inhibitor. On the other hand, serine/threonine protein kinase (PK) inhibitors, H-7, fasudil hydrochloride and M3, inhibited the Nef-induced apoptosis, and not the Fas-mediated one, without affecting the cell-binding activity of Nef and Nef-binding capacity of the activated cells. Preincubation of the cells with the drugs before being bound by Nef was required for the inhibition of apoptosis. These results suggest that the PK inhibitors specifically act on a cellular protein involved in the upper stream of signal transduction pathway of the Nef-induced apoptosis, which is different from the Fas-mediated pathway but meets it upstream of ICE. In addition, the drugs suppressed the cellular activation-associated cell surface expression of a putative Nef-binding protein in PBMC, although they had no influence on its expression in cell line cells. These findings suggest the feasibility of clinical use of the PK inhibitors to prevent the development of AIDS by inhibiting the Nef-induced apoptosis of uninfected blood cells.
Adult homozygous lap mice show various eye abnormalities, such as aphakia, retinal disorganization, and dysplasia of the cornea and anterior chamber. In the fetal eye of a homozygous lap mouse, the lens placode seems to develop normally. However, the lens vesicle progresses abnormally to form a mass of cells without a cavity, and the mass vanishes soon afterward. We examined cell death in the lens anlage of this mutant. The lens anlagen of homozygous lap and normal mice from days 10 to 12 of gestation were observed by light microscopy after DNA end-labeling by immunohistochemistry and by transmission electron microscopy. By light microscopy, a slight frequency of cell death was detected in the lens anlage encircling the surface ectoderm and in the anlage or in the anlage of both homozygous lap mice and normal mice at day 10 of gestation. Cell death was seen in the lens anlage encircling the surface ectoderm in the normal mouse and sporadically in the anlage of the homozygous lap mouse at day 10.5 of gestation. Cell death was visible at the area of the lens vesicle attached to the surface ectoderm and encircling the surrounding surface ectoderm in the normal mouse, and in the lens anlage encircling the surface ectoderm and the apex areas of the lens anlage in the homozygous lap mouse at day 11 of gestation. At day 12 of gestation, almost no cell death was observed in the lens anlage of the normal mouse. However, extensive areas of cell death were still seen in the lens anlage at its apex, at the inner region, and encircling the surface ectoderm in the homozygous lap mouse. Electron microscopic observation showed that the dead cells observed in the lens anlagen by light microscopy in normal and lap mice are the result of apoptosis. In lap mice, cells with cytoplasmic condensation were observed mainly at days 10 and 10.5 of gestation. Many apoptotic bodies which had been phagocytosed by adjacent cells were seen predominantly at day 11 of gestation. At day 12 of gestation, apoptotic bodies phagocytosed by adjacent cells, which were seen at day 11, were still predominant, but there were more apoptotic bodies per cell and more digested apoptotic bodies than at day 11. These results indicate that cell death, resulting from apoptosis is involved in the disappearance of the lens anlage of lap mice.
The Nef protein of HIV-1 binds to and induces apoptotic cytolysis of a broad spectrum of uninfected blood cells of humans and mice independently of CD95 (Fas). A 24-kDa glycoprotein responsible for Nef binding and the Nef-induced apoptosis has been identified on the surface of human CD4+ T cells. Using mouse monoclonal antibodies (mAbs) against the human Nef-binding protein and flow cytometry, we analyzed the expression of a corresponding protein on murine cells. The mAbs were shown to bind to the surface of various murine cell lines including T and B lymphocytes and macrophages, in a fashion similar to the binding by soluble Nef protein. The mAbs competed with the Nef protein in binding to the cell surfaces. Immunoprecipitation of cell membranes revealed a 25-kDa protein recognized by the mAbs. Treatment of the soluble Nef protein with anti-Nef (C terminus) mAb, but not anti-Nef (N terminus) mAb, deprived the Nef of the cell binding activity, indicating that binding site is located in the C-terminal domain. Cross-linking of the cell-bound mAbs with secondary antibodies induced apoptotic cytolysis, which occurred independently of CD95 (Fas). On the other hand, neither the mAbs nor the soluble Nef protein reacted with primary lymphocytes in a resting stage obtained from lymph nodes, thymus and spleen of 5-week-old mice. However, some of the cells, predominantly comprising CD4+ T cells, became positive for the both reactions after mitogenic stimulation with phytohemagglutinin, concanavalin A or lipopolysaccharide of Escherichia coli. These results suggest that the 25-kDa protein on murine cell surfaces corresponds to the human Nef binding protein and is responsible for the Nef-induced apoptosis, and that its expression on the cell surface depends on cellular activation.
Recent studies in genetically obese and diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats suggest defects of cholecystokinin (CCK)-A receptor gene expression and CCK-A receptor-mediated biological functions such as pancreatic juice, protein, and gastric acid secretion. The present studies were undertaken to further examine CCK-A receptor gene expression and CCK-A receptor-mediated biological functions in the pancreas, stomach, and brain of OLETF rats. Expression of the CCK-A receptor gene could not be detected in the stomach, pancreas and brain by the reverse-transcription polymerase chain reaction (RT-PCR) method and Southern blotting of the PCR products. Southern blot analysis of genomic DNA from OLETF and control Long-Evans Tokushima Otsuka (LETO) rats with CCK-A receptor fragment as a probe revealed different restriction bands. Expression of the CCK-B receptor gene was observed in the stomach, pancreas, and brain in both OLETF and LETO rats by the RT-PCR method, with expression of the CCK-B receptor gene markedly enhanced in OLETF rats compared with that in LETO rats. Consistent with the defect of CCK-A receptor gene expression, CCK-A receptor-mediated biological functions were not observed in these organs. Perfused exocrine and endocrine pancreas of OLETF rats were insensitive to CCK stimulation but not to carbamylcholine stimulation. Basal gastric acid and pepsinogen secretions in OLETF rats were higher than in LETO rats. OLETF rats showed a significantly higher average daily food intake, gained body weight faster, and were heavier than LETO rats. The present study confirmed that OLETF rats have CCK-A receptor gene anomalies and demonstrated deficient CCK-A receptor-mediated biological function in the pancreas, stomach, and brain.
Mutations in the fusion, F, protein of Sendai virus resulting in increased cleavability by ubiquitous host protease(s), and mutations in the matrix, M, protein resulting in bipolar budding, are both important determinants for the systemic infection in mice caused by the protease activating pantropic mutant, F1-R. Several mutants of Sendai virus (BY, BF, and KD-M) with phenotypes of bipolar budding and/or increased cleavability of F protein were isolated. Genomic RNA sequence analysis of the F and M genes of the mutants revealed that several deduced amino acids in the F and M proteins were different from those of F1-R, T-5 (a revertant of F1-R), and wild-type viruses. The BF and KD-M mutants that budded bipolarly and were also activated by ubiquitous proteases were examined for replication in tissue culture cells and in mice. All of the mutants exhibited multiple-step replication in MDCK, MDBK, and LLC-MK2 cells without trypsin, but formed plaques only in MDCK cells. One of the mutants, designated KD-52M, was similar to F1-R in that it formed plaques in all three cell lines without addition of exogenous protease. However, none of the mutants viruses, including KD-52M, caused a systemic infection in mice. The mutated M protein of F1-R enhances the disruption of microtubles. However, none of the mutants with a bipolar budding phenotype (BY, BF, and KD-M), disrupted the microtubules to the same extent as F1-R. All of these mutants had mutations in the M protein that were different from those found in F1-R. Taken together, these results suggest that mutations at Ser115 to Pro in the F protein and at Asp 128 to Gly and Ile210 to Thr in the M protein of F1-R are the mutations specifically required for the systemic infection caused by F1-R.
PURPOSE: This study was designed to evaluate the advantage of perfluorocarbon (PFC) emulsion priming for venoarterial extracorporeal membrane oxygenation (ECMO) by comparison with hydroxyethyl starch (HES) solution in rabbits (2.8 to 3.9 kg). RESULTS: ECMO initiation was accompanied by a profound decrease in hematocrit (from 40.1% to 14.9%) in both groups. The arterial and the right atrial oxygen contents in the PFC group (n = 4; 38.5 and 11.5 mL/dL) were greater than in the HES group (n = 5; 7.0 and 5.1 mL/dL). Right atrial oxygen tension in the PFC group increased at the beginning of ECMO (from 38.4 to 51.2 mm Hg; P = .031) and remained higher than in the HES group for 60 minutes. These results indicate that oxygen supply and extraction in the PFC group were much greater than in the HES group. However, plasma lactate increased progressively during the 120-minute ECMO procedure in both groups (from 1.8 to 14.5 in the HES group, and from 2.3 to 12.2 in the PFC group). CONCLUSION: Perfluorocarbon priming for ECMO, although providing high oxygen delivery and extraction, does not prevent anaerobic metabolism.
Heparin was covalently bonded to a new hollow-fiber dense membrane artificial lung and extracorporeal circuit using a silane coupling agent and polyethyleneimine. This study investigated whether prolonged, venoarterial bypass extracorporeal lung assist (V-A bypass ECLA) could be sustained in a goat by the combination of the new membrane lung and minimal systemic heparinization. We maintained ECLA with the hollow-fiber lungs (surface area, 0.8 m2) and circuits by titrating the activated clotting time (ACT) to below 150 s with minimal systemic heparinization in 5 goats. The outcome was assessed from the function of the artificial lung via macro and microscopic examinations after the experiments and the incidence of systemic complications. The 5 goats were maintained on ECLA for 6 to 27 days. The bypass flow rate, blood gases at the return and drainage sites, platelet counts, and platelet aggregation activity were well maintained. Although the hemoglobin concentration, hematocrit, and plasma protein at the start of the ECLA were significantly lower than the pre-ECLA values due to hemodilution, the values remained stable during ECLA. A cerebral infarction occurred in 1 goat. However, in the other 4 goats, no complications such as bleeding, thrombosis, or plasma leakage from the artificial lung were observed. Although several thrombi were observed in the stagnant area of the artificial lung, these local thrombi did not cause the function of the artificial lung to deteriorate. We found that this new type of highly biocompatible, dense membrane artificial lung, when combined with minimal systemic heparinization, prolonged ECLA without the deterioration of the artificial lung function and was suitable for prolonged ECLA.
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> Frequent fetal premature ventricular contractions were diagnosed at 39 weeks of gestation. To avoid unnecessary cesarean section, the mother was administered propranolol hydrochloride orally. The tococardiography became feasible and permitted us to evaluate fetal well-being. The patient successfully delivered transvaginally a male infant at 40 weeks of gestation.
Wild-type Sendai virus is exclusively pneumotropic in mice. Protease activation mutants, ts-f1 and F1-R, were isolated from persistently infected tissue culture cells. Additional mutants were isolated from wild-type Sendai virus with phenotypes similar to the pantropic mutant, F1-R. The genome of the mutants was sequenced and mutations were revealed in several proteins encoded by the genes. Three of the six mutations in the fusion (F) proteins were considered prime candidates for the determinant of pantropism. Characterization of the mutants led to the finding that the exchange (Ser to Pro) residue 115 next to the cleavage site of the F protein was the primary determinant that resulted in the enhanced cleavability of the F protein. Another important finding was bipolar budding of F1-R in polarized epithelial cells and mouse bronchial epithelium. This has been attributed to two mutations in the matrix (M) protein, at residues 128 (Asp to Gly) and 210 (Ile to Thr). Thus, the determinants of pantropism of F1-R are protease activation of the F protein and biopolar budding attributed to the mutated M protein.
The Nef protein of HIV-1 is suggested to play a role in depletion of uninfected CD4+ T cells leading to the development of AIDS. The recombinant soluble Nef protein was shown to bind to cell surfaces of various murine lymphoid cell lines, including T and B lymphocytes, mastocytoma cells and macrophages. Cross-linking of the cell-bound Nef protein with anti-Nef antibodies induced apoptotic cytolysis of the cells. Although primary lymphocytes from young mice resisted Nef binding and Nef-induced cytolysis, treatment of the cells with concanavalin A or phytohemagglutinin made them susceptible to these activities, indicating that cellular activation is required for the apoptosis. The Nef-induced apoptosis also occurred with murine cells not expressing CD95 (Fas). These findings were quite similar to those obtained for human blood cells, suggesting that the mouse is applicable for analysis of Nef activities. The Nef-induced apoptosis was efficiently suppressed by serine/threonine protein kinase inhibitors, H7, fasudil hydrochloride and M3, which did not inhibit CD95 (Fas)-mediated apoptosis. On the other hand, bisindolylmaleimide, a protein kinase C inhibitor which inhibits CD95 (Fas)-mediated apoptosis, did not affect Nef-induced apoptosis. These results suggest that the Nef-induced apoptosis of murine cells involved a serine/threonine protein kinase-dependent signal transduction pathway distinct from the CD95 (Fas)-mediated system.
Staphylococcal protein A (SpA) is a cell-wall-bound pathogenicity factor from the bacterium Staphylococcus aureus. Because of their small size and immunoglobulin (IgG)-binding activities, domains of protein A are targets for protein engineering efforts and for the development of computational approaches for de novo protein folding. The NMR solution structure of an engineered IgG-binding domain of SpA, the Z domain (an analog of the B domain of SpA), has been determined by simulated annealing with restrained molecular dynamics on the basis of 671 conformational constraints. The Z domain contains three well-defined alpha-helices corresponding to polypeptide segments Lys7 to Leu17 (helix 1), Glu24 to Asp36 (helix 2), and Ser41 to Ala54 (helix 3). A family of ten conformers representing the solution structure of the Z domain was computed by simulated annealing of restrained molecular dynamics using the program CONGEN. The average of the root-mean-square deviations (r.m. s.d.) of the individual NMR conformers, relative to the mean coordinates, for the backbone atoms N, Calpha and C' of residues Phe5 through Ala56 is 0.69 A; the corresponding backbone r.m.s.d. for the three-helical core is 0.44 A. Helices 1, 2 and 3 are antiparallel in orientation (Omega12=-170(+/-4) degrees , Omega13=+16(+/-3) degrees , Omega23=+173(+/-7) degrees ). A comparison of backbone amide hydrogen/deuterium exchange rates in free and IgG-bound Z domains demonstrates that the amide protons of helices 1, 2 and 3 are protected from rapid exchange in both states, indicating that all three helices are also intact in the IgG-bound state. These solution NMR results differ from the previously determined X-ray structure of the similar SpA B domain in complex with the Fc fragment of a human IgG antibody, where helix 3 is not observed in the electron density map and from the solution NMR structure of the B domain, where helix 3 is observed but helix 1 is tilted by approximately 30 degrees with respect to helices 2 and 3. Hydrogen-bonded N-cap and C-cap formation is observed for all three helices of the Z domain; these capping interactions appear to be highly conserved in the five homologous domains of SpA.
Borna disease virus (BDV), a neurotropic virus naturally infecting horses and sheep, has been suggested to be associated with human psychiatric disorders. Thus far no extensive studies have been done, providing the evidence of BDV genome in normal human brain tissue. We therefore examined four brain regions of 30 normal autopsy brains for BDV p24 genome. By highly sensitive nested reverse transcriptase (RT)-mediated PCR analysis, we found positive PCR products in two brains: one in frontal and temporal cortices and hippocampus and another in frontal cortex and olfactory bulb. Our results suggest that BDV can infect human brain tissue latently, without causing an apparent neuropsychiatric disorder.
The Nef protein of HIV-1 binds to uninfected CD4+T lymphocytes and induces apoptotic cytolysis of the cells. We examined several human blood cell lines and peripheral blood mononuclear cells (PBMCs) for Nef-induced apoptotic cell death. Soluble Nef protein was shown to bind to the cell surface of not only CD4+T cells but also CD8+T lymphocytes, B lymphocytes, macrophages and neutrophils. PBMCs from normal subjects resisted Nef binding, and activation of the cells with phytohemagglutinin or concanavalin A converted the cells to be susceptible to the binding. Cross-linking of the Nef proteins bound to the cell surfaces with anti-Nef antibody-induced apoptotic cytolysis of the cells. The Nef-mediated apoptosis occurred independently of CD95(Fas). These results suggest that soluble Nef protein, which is found in sera of HIV-1 infected patients, is involved in the destruction of a broad spectrum of uninfected blood cells leading to immune suppression.
An expert system for determining resonance assignments from NMR spectra of proteins is described. Given the amino acid sequence, a two-dimensional 15N-1H heteronuclear correlation spectrum and seven to eight three-dimensional triple-resonance NMR spectra for seven proteins, AUTOASSIGN obtained an average of 98% of sequence-specific spin-system assignments with an error rate of less than 0.5%. Execution times on a Sparc 10 workstation varied from 16 seconds for smaller proteins with simple spectra to one to nine minutes for medium size proteins exhibiting numerous extra spin systems attributed to conformational isomerization. AUTOASSIGN combines symbolic constraint satisfaction methods with a domain-specific knowledge base to exploit the logical structure of the sequential assignment problem, the specific features of the various NMR experiments, and the expected chemical shift frequencies of different amino acids. The current implementation specializes in the analysis of data derived from the most sensitive of the currently available triple-resonance experiments. Potential extensions of the system for analysis of additional types of protein NMR data are also discussed.