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Biomedical subjects

T Fujiwara

Publications and source records attributed to T Fujiwara.

At least 1,009 records · Page 56Linked to original sources
PubMed1988

Positron CT imaging of an impending stroke.

We present PET findings of a case of a transient ischemic attack which later progressed to cerebral infarction. Cerebral blood flow at the stroke focus in the right parietal cortex measured after a TIA attack and before stroke was as low as 24 ml/100 g/min with some increase in oxygen extraction fraction and blood volume. The condition was compatible with "misery perfusion". This case may be an example suggestive that the "misery perfusion sign" is a warning of impending stroke and its poor prognosis if left without appropriate treatments.

Aged↗
PubMed1988

Surfactant replacement therapy in neonatal respiratory distress syndrome. A multi-centre, randomized clinical trial: comparison of high- versus low-dose of surfactant TA.

We conducted a prospective, randomized, controlled trial comparing the efficacy of two doses of a reconstituted bovine surfactant (Surfactant TA) in premature infants requiring mechanical ventilation shortly after birth for respiratory distress syndrome. Forty-six infants weighting 1000-1499 g were randomized into two groups: a low-dose group (23 infants given a single dose of 60 mg surfactant lipid/kg) and a high-dose group (23 infants given a single dose of 120 mg/kg). The mean (SD) age at which surfactant was given was 5.5 (+/- 1.2) h in the low-dose group and 6.0 (+/- 1.5) h in the high dose group. Both treatments improved oxygenation (increased arterial-alveolar PO2 ratio) with decreased mean airway pressure, the high-dose surfactant having a more beneficial effect in prolonging the response. Infants in the high-dose group had significantly less (P less than 0.05) incidence of both intraventricular haemorrhage and bronchopulmonary dysplasia. This prospective trial documents that a greater benefit can be obtained by increasing the dose of surfactant (120 mg/kg) beyond 60 mg/kg treatment of premature infants with severe respiratory distress syndrome (RDS).

Clinical Trials as Topic↗
PubMed1988

Electron microscopic studies of the endocytotic process of cationized ferritin in cultured human retinal pigment epithelial cells.

The endocytotic process in cultured human RPE cells was observed after 1 min, 20 min, and 2 h incubation with cationized ferritin. Within 1 min the ferritin particles were seen to attach to the cell membrane, especially between microvilli. Uncoated and coated pits could be recognized on the cell membranes, and uncoated and coated endocytotic vesicles were found in the cytoplasm after 20 min of incubation. These vesicles were surrounded by abundant microfilaments and had no visible membranes. Loss of membrane may be an initial step in the process of developing into the irregular clumps of ferritin particles found inside the plasma membrane. With time, more irregular clumps of ferritin, smaller than the particles introduced during incubation, appeared just beneath the cell membrane. Lysosomes were adjacent to the clumps of ferritin particles associated with microtubules and finally degraded these particles. The phagolysosomes containing many particles were surrounded by many microtubules. Small ferritin particles surrounded but had not entered the rough endoplasmic reticulums, and no particles were seen either around or in the Golgi apparatus.

Cations↗
PubMed1988

Electron microscopic comparative studies of phagocytic processes between outer segments and latex microspheres in cultured human retinal pigment epithelial cells.

The process of phagocytosis in cultured human retinal pigment epithelium (RPE) cells was observed after more than 2 h of incubation with human outer segments and latex microspheres. Fingerlike microvilli were attached to outer segments and entwined around both its ends. The microvilli enveloped the outer segment and cut into the membranous structure, and the same process as that seen in in vivo shedding was observed. The looplike disk membranes and the whole of the outer segment were ingested into the cytoplasm and degraded by the lysosome. Latex microspheres were also ingested into the cytoplasm so as to be enveloped in many fingerlike microvilli. Microfilaments were concentrated in the vicinity of latex microspheres and outer segments, and latex microspheres were placed between two microtubules. Furthermore, when latex microspheres and outer segments were ingested into the cytoplasm, the dilated rough endoplasmic reticulum (rER) contained materials of high electron density and attached ribosomes increased. The rER of the cultured human RPE cells seemed to show a high level of protein synthesis during the phagocytic process. It was observed that cytoskeletons, such as microfilaments and microtubules, and lysosomes had important functions in the phagocytic process, and that there were basically no differences among the objects phagocytized by the cultured RPE cells.

Cells, Cultured↗
PubMed1988

Coronary flow characteristics of left coronary artery in aortic regurgitation before and after aortic valve replacement.

In 6 patients with pure aortic regurgitation, the velocity waveform in the left anterior descending coronary artery (LAD) was measured using an 80-channel 20-MHz-pulse Doppler velocimeter before and immediately after aortic valve replacement. All patients showed normal coronary angiograms. Flow velocity was analyzed by both zero-cross and fast Fourier transform methods in real time. The LAD flow in severe aortic regurgitation was characterized by an increase in the systolic flow component, a small and rapidly decreased diastolic flow, an irregular velocity profile across the vessel, and a wider velocity spectrum. After aortic valve replacement, systolic flow decreased by 36.3 +/- 21.7% (p less than 0.01), whereas diastolic flow increased by 81.4 +/- 51.8% (p less than 0.05). The ratio of diastolic flow to total LAD flow increased from 63 +/- 13% to 82 +/- 7% (p less than 0.05). The velocity profile became more parabolic and had a narrow spectrum. These results suggest that operation for aortic regurgitation induces beneficial effects on the myocardial inflow immediately after valve replacement.

Adult↗
PubMed1988

Restoration of Ca2+-activated tension of CDTA-treated single skeletal muscle fibers by troponin C.

Single fibers from glycerinated rabbit psoas muscle were treated with a solution containing CDTA, a strong chelator of metal ions. The CDTA-treated fibers lost all of the troponin C and showed no Ca2+-activated tension development. The addition of troponin C restored the Ca2+-activated tension of CDTA-treated fibers. The tension-pCa relationship in the case of the CDTA-treated fibers reconstituted with troponin C was almost the same as that in the case of the same fibers before the CDTA treatment. These results are consistent with those of the previous study on the Ca2+-activated ATPase of CDTA-treated rabbit skeletal myofibrils.

Animals↗
PubMed1988

Serological properties and immunobiological activities of lipopolysaccharides from black-pigmented and related oral Bacteroides species.

Lipopolysaccharides (LPS) from five species of oral Bacteroides, B. gingivalis strains 381 and ATCC 33277, B. oralis ATCC 33269, B. loescheii ATCC 15930, B. intermedius ATCC 25611 and B. corporis ATCC 33547, were extracted from whole cells by the phenol/water procedure, and subsequently purified by treatment with nuclease and ultracentrifugation. The LPS were composed of hexoses, glucosamine, fatty acids and phosphorus. Heptose and 2-keto-3-deoxyoctonate were not detected. The LPS preparations from B. gingivalis strains 381 and ATCC 33277 presented very similar SDS-polyacrylamide gel electrophoresis patterns when stained with ammoniacal silver. They produced a fused precipitin band against an antiserum to B. gingivalis 381 LPS in immunodiffusion tests. Antisera raised against the LPS from B. loescheii and B. intermedius reacted with the LPS prepared from all the oral Bacteroides strains except those of B. gingivalis. All the LPS preparations were mitogenic for spleen cells of BALB/c (nu/nu) mice, but not for thymus cells from C3H/HeN mice. The LPS induced marked mitogenic responses and polyclonal B cell activation for spleen cells of not only C3H/HeN (LPS responder) mice, but also C3H/HeJ (LPS nonresponder) mice. The mitogenic responses were not suppressed significantly upon addition of polymyxin B to the reaction mixture. These LPS also enhanced interleukin-1 production by murine peritoneal macrophages and mouse cell line J744. 1 macrophages. Hydrolysis of B. gingivalis ATCC 33277 LPS in 1 m-HCl at 100 degrees C for 1 h yielded lipid and polysaccharide. The lipid portion was largely composed of fatty acids and glucosamine, and was mitogenic for spleen cells from C3H/HeJ as well as C3H/HeN mice, while the polysaccharide portion induced no significant mitogenic responses under similar experimental conditions.

Animals↗
PubMed1988

Immunobiological properties of lipopolysaccharides isolated from Fusobacterium nucleatum and F. necrophorum.

Lipopolysaccharides (LPSs) were isolated from Fusobacterium nucleatum ATCC 10953 and F. necrophorum ATCC 25286 by the hot phenol/water procedure. F. nucleatum LPS was composed of 16% (w/w) carbohydrate, 10% (w/w) hexosamine and 40% (w/w) fatty acid, while F. necrophorum LPS was composed of 26% (w/w) carbohydrate, 12% (w/w) hexosamine and 28% (w/w) fatty acid. These LPS preparations induced mitogenic responses in spleen cells of BALB/c, BALB/c (nu/nu) and C3H/HeN mice, and these responses were suppressed by the addition of polymyxin B. The preparations also induced the polyclonal responses of C3H/HeN spleen cells. In addition, enhanced glucose utilization and interleukin-1 production by murine peritoneal macrophages were demonstrated. Neither spleen cells nor macrophages from the 'LPS-nonresponsive' C3H/HeJ mouse were activated by LPSs from the Fusobacterium species.

Animals↗
PubMed1988

Effects of panose on glucan synthesis and cellular adherence by Streptococcus mutans.

The effects of panose on glucan synthesis and sucrose-dependent cellular adherence by Streptococcus mutans were investigated. Panose effectively inhibited glucan synthesis from sucrose by glucosyltransferases from S. mutans strain 6715, but increasing amounts of panose increased the release of fructose from sucrose by the enzymes. On the other hand, production of a series of oligosaccharides of increasing size by the enzymes was markedly enhanced in the presence of panose. These results indicate that panose activates the enzymes and that the inhibition of glucan synthesis by panose is due to the transfer of the glucosyl group of sucrose to panose. Sucrose-dependent adherence of cells of various S. mutans strains to a glass surface was also inhibited by panose.

Bacterial Adhesion↗
PubMed1988

The caries inhibitory effects of GOS-sugar in vitro and in rat experiments.

The caries inhibitory activity of GOS-sugar (panose- and maltose-rich sugar mixture) was examined and compared with that of sucrose, maltose, or glucose in in vitro and in vivo experiments. Streptococcus mutans MT8148R (serotype c) and Streptococcus sobrinus 6715 (g) did ferment GOS-sugar and produce acid in a similar way as with maltose and glucose. However, GOS-sugar could not be a substrate for the glucosyltransferases (GTases) of these mutans streptococci to synthesize the water-insoluble glucan. Also, it significantly inhibited not only the synthesis of water-insoluble glucan from sucrose by the crude GTases but also the sucrose-dependent adherence of these cells to a glass surface. In particular, adherence of growing cells of 6715 was markedly inhibited by the presence of GOS-sugar. GOS-sugar was found to induce significant but minimal dental caries in SPF rats infected with either MT8148R or 6715. Furthermore, the replacement of half of the dietary sucrose content with GOS-sugar resulted in a significant reduction of caries development in rats infected with strain 6715.

Animals↗
PubMed1988

Factor VIII polypeptide specificity of monoclonal anti-factor VIII antibodies.

Four monoclonal antibodies against factor VIII, NMC-VIII/1, NMC-VIII/2, NMC-VIII/3 and NMC-VIII/4, were produced. The first three antibodies were of the IgG1 immunoglobulin subclass, while the fourth was IgM. The affinity of each antibody for factor VIII was high and anti-factor VIII clotting activity was detected in NMC-VIII/2, NMC-VIII/3 and NMC-VIII/4. NMC-VIII/1 had no inhibitory effect on factor VIII clotting activity. Immunoblotting using purified intact and thrombin-treated factor VIII identified the antibodies' factor VIII polypeptide specificities. With thrombin-treated factor VIII the factor VIII fragments for NMC-VIII/1 and NMC-VIII/2 were 80 kDa and 54 kDa, respectively, while both NMC-VIII/3 and NMC-VIII/4 recognised a 44 kDa fragment. With intact factor VIII, antibodies NMC-VIII/2-4 bound to polypeptides larger than 90 kDa, especially NMC-VIII/2, which reacted with a chain of 330 kDa thought to be a mature form of factor VIII protein. We also detected a mature form of factor VIII in hepatic sinusoidal endothelial cells by immunoperoxidase staining. Identification of the factor VIII polypeptides bearing these fragments enabled us to clarify the localization of the factor VIII thrombin cleavage site, and suggested the existence of factor VIII in hepatic sinusoidal endothelial cells.

Animals↗
PubMed1988

A comparative study of absence status epilepticus between children and adults.

Based on the clinicoelectrographic data of 28 patients (14 children and 14 adults) with absence status epilepticus thoroughly documented by CCTV/EEG, it was found that there were significant differences between the children and adults. In childhood, absence status tended to occur in those who had experienced individual short-lived atypical absence seizures and also other types of generalized seizure. In contrast, there was a general tendency for absence status in adulthood to occur in females without individual absence seizure. With respect to the clinicoelectrographical manifestations, absence status with a decreased postural tone was prone to be associated with a more profound clouding of consciousness, whereas in those with myoclonic components there was a less profound clouding. The former was found solely in children while the latter was both in children and in adults. During absence status, the focal motor features with or without secondarily generalized convulsions were observed in 8 adult patients (57%). On the other hand, no focal motor manifestations were observed during absence status in children. Absence status is composed of two modalities: either a prolongation or repetition of absence seizures. It was demonstrated that, in children, either the prolongation or repetition of individual absence seizures developed into absence status. The short-lived absence was of an atypical nature, whereas in adults, absence status consisted of the prolongation of an absence seizure which occurred in patients with no experience of individual absence seizures. With respect to the drug treatment, antiabsence drugs had some effect in children, while none of the adult patients responded either to the antiabsence drugs or other antiepileptic drugs. The long-term seizure prognosis was not necessarily poor in children but invariably poor in adults. Four adult patients showed diffuse, but unilateral frontally accentuated asymmetrical paroxysmal activity during the status. Three of them showed initial localized spike-wave discharges in the unilateral frontal region followed by a generalized spike-wave rhythm. Furthermore, all of these 4 patients with focally accentuated ictal EEGs have shown partial motor seizures intermingled with absence status.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1988

Relaxing actions of procaterol, a beta 2-adrenoceptor stimulant, on smooth muscle cells of the dog trachea.

1. The effects of procaterol, a beta 2-adrenoceptor agonist, on smooth muscle cells of the dog trachea were investigated by use of microelectrode and isometric tension recording methods, and by measurement of Ca transients as estimated from the fura-2 fluorescence, adenosine 3':5'-cyclic monophosphate (cyclic AMP) and breakdown of phosphatidylinositols. 2. Procaterol hyperpolarized the membrane and increased the ionic conductance (above 10 nM) in a dose-dependent manner. These actions were inhibited by propranolol. 3. Procaterol inhibited the mechanical responses evoked by acetylcholine (ACh), histamine or 5-hydroxytryptamine (5-HT), in the presence or absence of Ca2+ in the bath solution, but not that evoked by high concentrations of ACh (1 microM). The ID50 value of procaterol for the peak amplitude of the ACh-induced contraction (30 nM) was 0.3 nM. The equivalent values for the histamine-induced phasic and tonic responses (10 microM) were 0.15 and 0.01 nM), respectively. 4. Procaterol (over 1 nM) increased the amount of cyclic AMP in a dose-dependent manner which was blocked by prior application of propranolol. 5. Procaterol did not alter the changes in the amounts of phosphatidylinositol 4,5-bisphosphate (PI-P2) and phosphatidic acid (PA) induced by ACh, histamine or 5-HT. Thus, the synthesis of inositol 1,4,5-trisphosphate is not affected by stimulation of the beta 2-adrenoceptor. 6. ACh increased the free Ca2+ concentration to a greater extent than that produced by histamine or 5-HT. These changes were reduced by procaterol, except for those induced by high concentrations of ACh (over 1 microM). 7. It is concluded that procaterol relaxes tissues precontracted by various agonists due to a reduction in the free Ca2+. This inhibitory action may be due to an increase in the amount of cyclic AMP but does not result from an inhibition of the hydrolysis of phosphatidyl inositols. The hyperpolarization induced by procaterol may partly contribute to the observed relaxation.

Adrenergic beta-Agonists↗
PubMed1988

Regional differences in the mechanical properties of rabbit airway smooth muscle.

1. In studies of rabbit airway smooth muscle, differences in mechanical responses to acetylcholine, histamine and high K+ in intact muscles, and in Ca2+ sensitivity in skinned muscles, have been examined in tissue taken from 5 different regions of the airway. Interactions between prostaglandin F2 alpha and epithio-thromboxane A2 and the above spasmogenic agencies were also studied. 2. Mechanical responses to histamine (10 microM) and to 128 mM K+ were smallest in trachea and were largest in 3rd and 4th order bronchi. In all regions, spasm evoked by 10 microM acetylcholine was greater than that evoked by 10 microM histamine or 128 mM K+. 3. In the third and fourth branches of the rabbit right middle bronchus, contractions evoked by 10 microM acetylcholine, 10 microM histamine and 128 mM K+ showed similar amplitudes of phasic response. In Ca2+-free solution containing 2 mM EGTA, the phasic components of the acetylcholine- or histamine-induced contraction remained unchanged in comparison with that observed in Krebs solution, but the phasic and tonic components of the K+-induced contraction and the tonic changes induced by acetylcholine and histamine were abolished. 4. Two subtypes of the histamine receptor, excitatory H1- and inhibitory H2- receptors were detected on the bronchial smooth muscle. The H1-induced contraction was mediated by release of stored Ca2+ together with activation of Ca2+ influx relatively insensitive to Ca2+ antagonists. 5. The -log(EC50) values for acetylcholine and histamine (in the presence of cimetidine and atropine) were 6.11 +/- 0.11 and 5.33 +/- 0.08, respectively, in the third branch of right middle bronchus. These values were similar to those observed for trachea. 6. Prostaglandin F2. (10 microM) and 9,11-epithio-11,12-methano-thromboxane A2 (0.1 microM) neither provoked nor enhanced the contractions evoked by any stimulants. 7. No difference was observed between the Ca2+ sensitivity of chemically skinned muscle from the trachea and that of muscle from the third branch of the right middle bronchus. 8. Regional differences in the response to histamine and acetylcholine observed in airway smooth muscles are discussed and it is concluded that these may be due to differences in receptor numbers.

Acetylcholine↗
PubMed1988

Hyperglycemia induced by electrical stimulation of lateral part of dorsal parabrachial nucleus.

Electrical stimulation of the lateral part of the dorsal parabrachial nucleus (PBD) induces hyperglycemia by enhancing glucagon secretion and suppressing insulin secretion in rats. The mechanism of this effect in the light period was examined by use of blockers of the autonomic nervous system. Hexamethonium, a ganglion blocker, and propranolol, a beta-adrenergic blocker, markedly inhibited the hyperglycemic response to stimulation of the lateral part of the PBD (LPBD). In contrast, phenoxybenzamine, an alpha-adrenergic blocker, and atropine methylnitrate, a muscarinic blocker, had no effect. Because previous studies showed that bilateral lesions of the suprachiasmatic nucleus (SCN) eliminated hyperglycemia induced by intracranial injection of 2-deoxy-D-glucose and that blinding largely suppressed the hyperglycemia, the effects of these two treatments on hyperglycemia induced by electrical stimulation of the LPBD were examined. SCN lesions abolished the hyperglycemic response but did not affect the hyperglucagonemic response. Results 4 wk after orbital enucleation were similar to those after SCN lesions. These findings suggest that the SCN and a beta-adrenergic mechanism are involved in the hyperglycemic response to LPBD stimulation.

Animals↗
PubMed1988

Pathological features of coronary arteries in children with Kawasaki disease in which coronary arterial aneurysm was absent at autopsy. Quantitative analysis.

Coronary arteries in six children who had Kawasaki disease but lacked coronary arterial aneurysms were examined. Four children died of myocarditis at the acute stage, and two children died of bacterial sepsis or as a result of an occurrence during cineangiography at the healed stage. Twenty-one children without Kawasaki disease were examined as controls. The six children with Kawasaki disease had no thrombi, recanalization, or stenosis greater than 50% in the major coronary arteries. Three patients had dilatation of the major coronary arteries at the acute stage. Two of the three patients died during the acute stage, and autopsy showed slight dilatation of coronary arteries and abnormal intimal thickening due to panvasculitis. In the third child, who died at the healed stage, dilatation of the coronary arteries detected by two-dimensional echocardiography at the acute stage had disappeared at the healed stage. No dilatation of the major coronary arteries was seen at autopsy. However, abnormal fibrous intimal thickening of the major coronary arteries without inflammatory changes was found. The other three patients had no dilatation of the major coronary arteries at the acute stage. Two patients died at the acute stage, and slight inflammation without abnormal intimal thickening was seen in the intima and the adventitial area. In the third patient, who died during the healed stage, two-dimensional echocardiography revealed no dilatation during the clinical course, and there was no inflammatory changes or abnormal intimal thickening at autopsy.(ABSTRACT TRUNCATED AT 250 WORDS)

Arteries↗