Electronic transport of quasicrystals with random phason strain: The two-dimensional Penrose lattice.
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Journal Article↗
Biomedical subjects
T Fujiwara
Publications and source records attributed to T Fujiwara.
Alteration of [3H]hemicholinium-3 binding in the post-ischaemic gerbil brain.
To determine whether presynaptic sites are resistant to cerebral ischaemia, we investigated the postischaemic alteration in [3H]hemicholinium-3 binding as a sensitive marker of presynaptic cholinergic terminals in the gerbil brain between 1 h and 7 days after recirculation using receptor autoradiography. Transient ischaemia was induced for 10 min. [3H]hemicholinium-3 binding was unchanged in the frontal cortex, striatum and hippocampus throughout the recirculation periods. Our histological study revealed conspicuous neuronal damage in the frontal cortex, striatum, hippocampal CA1 sector and hippocampal CA3 sector after ischaemia. The present study demonstrates that presynaptic sites in selectively vulnerable areas can maintain their structural components although postsynaptic neurones are clearly degenerated. Thus our findings support the hypothesis that presynaptic sites are particularly resistant to ischaemia, but postsynaptic sites are vulnerable.
Animals↗
Electronic structures of transition-metal mono-oxides in the self-interaction-corrected local-spin-density approximation.
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Journal Article↗
Rat HPC-1/syntaxin 1A and syntaxin 1B interrupt intracellular membrane transport and inhibit secretion of the extracellular matrix in embryonic cells of an amphibian.
HPC-1/syntaxin 1A and syntaxin 1B are proteins that have been implicated in the docking and/or fusion of synaptic vesicles to the presynaptic plasma membrane in neural cells. Capped RNAs (cRNAs) for rat HPC-1 and syntaxin 1B were injected into embryonic cells of an amphibian, the Japanese newt. The effects of the proteins translated from the injected cRNAs on intracellular membrane transport and secretion of the extracellular matrix (ECM) were then investigated. Immunoblotting and immunoelectron microscopy showed that the HPC-1 synthesized in the embryonic cells was localized on the membranes of Golgi complexes and vacuoles and on the plasma membrane. Electron microscopy revealed the morphological deformation of Golgi complexes, an appearance of large number of vacuoles, and the disappearance of the ECM from the cell surface in the cRNA-injected embryos. The results showed that HPC-1 and syntaxin 1B interrupt the pathways of intracellular membrane transport and inhibit the secretion of ECM by amphibian embryonic cells. Similar mechanisms may be involved in regulation of the secretory process of synaptic vesicles in mammalian neural cells and in regulation of intracellular membrane transport and constitutive secretion of ECM in amphibian embryonic cells.
Animals↗
Fine structure and distribution of lymphatics in the synovial membrane of monkey and human knee joints. A study using an enzyme-histochemical method.
The fine structure and distribution of lymphatics in the synovial membrane of monkey knee joints, and human knees with osteoarthritis and rheumatoid arthritis, were studied by light and electron microscopy using an enzyme-histochemical method. Whole mount preparations and tissue sections were doubly stained for 5'-nucleotidase and alkaline phosphatase. The 5'-nucleotidase positive lymphatics could be distinguished from the alkaline phosphatase positive blood vessels. In monkey specimens the 5'-nucleotidase lymphatics were densely distributed in the medial and lateral parts of the suprapatellar pouch and infrapatellar fat pad, in both the superficial and deep of the sublining cell layers. Collecting lymphatics were well developed in the deep fibrous layer and in the merging epimysium. In the knees with both types of arthritis, the patterns of distribution were the same as in the monkey. No lymphatics were found in well developed villi in rheumatoid arthritis, but many blood vessels were present.
Animals↗
Thioredoxin h is one of the major proteins in rice phloem sap.
Sieve tubes play important roles in the transfer of nutrients as well as signals. Hundreds of proteins were found in pure phloem sap collected from rice (Oryza sativa L. cv. Kantou) plants through the cut ends of insect stylets. These proteins may be involved in nutrient transfer and signal transduction. To characterize the nature of these proteins, the partial amino-acid sequence of a 13-kDa protein, named RPP13-1, that was abundant in the pure phleom sap was determined. A cDNA clone of 687 bp, containing an open reading frame of 122 amino acids, was isolated using corresponding oligonucleotides as a probe. The deduced amino-acid sequence was very similar to that of the ubiquitous thiol redox protein, thioredoxin. The consensus sequences of thioredoxins are highly conserved. No putative signal peptide was identified. Antiserum against wheat thioredoxin h cross-reacted with RPP13-1 in the phloem sap of rice plants. RPP13-1 produced in Escherichia coli was reactive to antiserum against wheat thioredoxin h. Both E. coli-produced RPP13-1 and the phloem sap proteins catalyzed the reduction of the disulfide bonds of insulin in the presence of dithiothreitol. These results indicate that an active thioredoxin is a major protein translocating in rice sieve tubes.
Amino Acid Sequence↗
Purification, primary structure, and evolution of cytochrome c-550 from the magnetic bacterium, Magnetospirillum magnetotacticum.
Cytochrome c-550 was purified from Magnetospirillum magnetotacticum to an electrophoretically homogeneous state, and some of its properties were determined. The cytochrome showed absorption peaks at 528 and 409 nm in the oxidized form, and at 550, 521, and 414 nm in the reduced form. Its midpoint redox potential at pH 7.0 was determined to be +289 mV. The primary structure of cytochrome c-550 was determined. Cytochrome c is composed of 97 amino acid residues, and its molecular weight was calculated to be 10,873, including heme c. Its primary structure is very similar to those of Rhodospirillum fulvum and Rhodospirillum molischianum cytochromes c2, suggesting that M. magnetotacticum is phylogenetically related to photosynthetic bacteria.
Amino Acid Sequence↗
The amino acid sequence of Nitrosomonas europaea cytochrome c-552.
The complete amino acid sequence of cytochrome c-552 derived from the chemoautotrophic ammonia-oxidizing bacterium Nitrosomonas europaea was determined. The cytochrome consisted of 81 amino acid residues, and its molecular weight was calculated to be 9098 including heme c. Although the sequence of cytochrome c-552 was highly homologous to those of cytochromes c-551, which were known as the electron-donating components to dissimilatory nitrite reductase in pseudomonads, cytochrome c-552 differed from cytochrome c-551 in two points: (1) the sequence of cytochrome c-552 was shorter by two amino acid residues than that of cytochrome c-551 at the N-terminus and (2) one amino acid insertion was present in cytochrome c-552.
Amino Acid Sequence↗
Reactivity of the co-type and baa3-type cytochrome c oxidases from Pseudomonas aeruginosa with different endogenous cytochromes c.
The reactivity between different cytochromes c purified from Pseudomonas aeruginosa cells grown aerobically in the absence of nitrate and isolated cytochromes co and baa3 was determined. The P. aeruginosa cytochrome co reacted most rapidly with the membrane-bound cytochrome c-551 among three c-type cytochromes analyzed, whereas the cytochrome baa3 reacted best with the membrane-bound cytochrome c-555. The results indicated that two terminal electron transfer systems are present in aerobic P. aeruginosa: one contains the cytochrome c-551 and cytochrome co, and the other contains the cytochrome c-555 and cytochrome baa3.
Aerobiosis↗
Determinants of drug response in camptothecin-11-resistant glioma cell lines.
Camptothecin-11 (CPT-11) is a new derivative of camptothecin, a plant alkaloid antitumor agent. Previous studies indicated that antitumor activity of CPT-11 was mediated through interaction of the drug with its target enzyme, DNA topoisomerase I (topo I). To elucidate the mechanisms of CPT-11 resistance, we have characterized glioma cell lines (T98G/CPT-11, C6/CPT-11) selected from the wild types (T98G. C6) for acquired resistance to CPT-11. T98G/CPT-11 and C6/CPT-11 cells demonstrated 5.4- and 7.3-fold increases, respectively, in resistance to CPT-11. Total glutathione S-transferase (GST) and GST-p activities were similar in CPT-11-sensitive and -resistant cells. No difference in intracellular accumulation of CPT-11 was observed between CPT-11-resistant and parental cells, indicating that an alteration in the uptake was not responsible for resistance. In addition, CPT-11-resistant cell lines showed no change in the total activity of Topo I, indicating an alteration in total Topo I was not responsible for resistance. In contrast, significantly increased intracellular glutathione (GSH) levels levels were found in T98G/CPT-11 and C6/CPT-11 cells (4.3- and 2.1-fold). Furthermore, Topo I samples from T98G/CPT-11 and C6/CPT-11 cells were at least 4- and 2-fold more resistant to the inhibitory effect of the CPT-11 on the relaxation activity of Topo I than were Topo I samples from their respective parent lines. The resistance of the enzyme itself to the effects of CPT-11 may be responsible for the resistance to CPT-11. Thus, at least two distinct mechanisms have been selected for the CPT-11-resistant cells.
Animals↗
Intraoperative radiotherapy for gliomas.
Intraoperative radiotherapy (IORT) was performed in 20 of 36 patients with glioma; 11 glioblastomas, 7 malignant astrocytomas, 2 benign astrocytomas. Twenty or 25 Gy of irradiation was delivered in a single fraction intraoperatively, followed by external beam irradiation. The electron beam energy was selected so that the 80% isodose line fell at 2 or 3 cm below the residual tumor surface. Median survival time of IORT group was 14 months and that of the control group was 10 months. Difference of survival curve was significant. There were 6 incidences of complication caused by IORT; 1 radionecrosis, 1 convulsion, 1 abscess, and 3 severe brain edemas. IORT is suited for the treatment of malignant gliomas.
Adult↗
Cardiopulmonary function in bicycle racing over mountainous terrain at moderate altitude.
To examine cardiopulmonary function during exercise in a mountainous region at moderate altitude, we measured cardiac frequency, oxygen consumption (VO2), and percentage arterial hemoglobin oxygen saturation (%SaO2) before and after a bicycle race with a starting point at 638 m and finishing point at 1980 m. The time required to ascend an elevation of 10 m was prolonged with increasing altitude, and heart rate also increased with altitude. The %SaO2 at the starting point and at the finishing point differed significantly (P < 0.01). Faster cyclists exhibited higher %SaO2 and lower VO2, while slower cyclists exhibited a reduction in %SaO2 and an increase in VO2 immediately after the race. The %SaO2 recovery time was significantly correlated with the racing time (r = 0.54, P < 0.001). Therefore, the faster cyclists' oxygen debt upon completion of the race may be small and recovery of cardiopulmonary function may be fast, while the slower cyclists' oxygen debt may be large and recovery of cardiopulmonary function may be slow.
Adult↗
Cardio-pulmonary function of cyclists competing on an ascending mountain course between altitudes of 1400 m and 2800 m.
Physiological changes were investigated in the cardio-respiratory function of competitors in a bicycle race which involved not a flat course but ascending a mountain, from 1400 m to 2800 m. Heart rate throughout the race, arterial oxygen saturation and pulmonary function before and after the race of well trained competitors were measured. The individual's maximal heart rate during the race was designated as HRmax for the calculations. (1) There were significant correlations between the age and the mean %HRmax during the race, between mean %HRmax and time, and between age and time (n = 15); the mean %HRmax had a 3.90 times greater effect on time than did age. (2) The individuals who performed best had lower values of oxygen saturation just after finishing the race (n = 51). (3) At 1 min after reaching the finishing line, oxygen saturation levels had recovered to the value of 20 min after finishing the race, whereas the heart rate was still in the process of recovery (n = 18). (4) Maximum expiratory flow at 50% vital capacity measured 30 min after reaching the finishing line was significantly higher than at the starting point. The intensity of the load on the cardiac system produced by completion of this course was estimated to be almost the same as that of a full marathon on a flat course. The time depended on both the youth of the cyclist and on his ability to maintain a high value of %HRmax during the race.
Adolescent↗
Detection of human papillomavirus type 57 in a case of inverted nasal papillomatosis in Japan.
Human papillomavirus (HPV) type 57 DNA was detected in recurrent nasal inverted papillomatosis, in a 60-year-old Japanese male, using Southern blot hybridization. HPV types 6, 11, 16 and 18 were not detectable in the papilloma. Previous studies have shown that HPV types 6, 11, 16 and 18 were mainly found in nasal papillomatosis in other laboratories but the actual detection rate of virus was low. We speculate that this low detection rate may be due to the lack of a method for detecting HPV type 57.
Blotting, Southern↗
Are autoimmune mechanisms involved in critical illness polyneuropathy?
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Aged↗
Validation of noninvasive quantification of rCBF compared with dynamic/integral method by using positron emission tomography and oxygen-15 labeled water.
This study proposes a new solution for the quantification of rCBF pixel-by-pixel using PET and 15O-H2O. The method represents an application of weighted integration that used PET image only, requiring no input function of arterial blood. It generates the rCBF image quickly and automatically. Simulation studies revealed that the calculation of rCBF was fairly stable as long as a relatively shorter scan frame time and longer scan time were selected. Calculated images of actual PET study by this method correlated significantly with those identified by the dynamic/integral method. Because this procedure could detect whole brain CBF change between different studies as accurately as by the dynamic/integral method, this procedure may be the most suitable for brain activation studies.
Cerebrovascular Circulation↗
A bolster suture technique for ear reconstruction for microtia without skin necrosis.
A new bolster suture technique to prevent skin necrosis in microtia ear reconstruction is presented. An outer series of bolsters is placed distant from the ear framework in a zigzag fashion, the temporal skin being gathered on the framework. In this way, the skin flap overlying the framework is relaxed and has sufficient blood flow. Therefore the skin flap can be thinned with little risk of necrosis. Furthermore, the contour of the reconstructed auricle is accentuated because of the thin relaxed overlying skin. Seven ears with microtia were reconstructed using this method. The results were satisfactory, except for one auricle which became slightly congested at the conchal portion due to excessive thinning. There were no haematomas or skin necrosis.
Adolescent↗
Choledochal cysts: special emphasis on the usefulness of intraoperative endoscopy.
Long-term complications after excisional surgery for choledochal cyst include stone formation within the intrahepatic bile duct (IHBD) and within the intrapancreatic portion of the bile duct (IPBD). The authors reviewed 180 patients with choledochal cysts (137 women) seen during a 30-year period and report their recent experience with intraoperative cyst endoscopy. Primary cyst excision with hepaticoenterostomy was performed in 150 cases, and a secondary cyst excision, after various lesser drainage procedures, in 24. Six children were treated early in the series with a cyst enterostomy. The mean age and follow-up period were 4.3 and 9.4 years, respectively. At surgery, dilatation of the IHBD was identified in 96 patients, and protein plugs or stones were observed in 31 common pancreaticobiliary channels. Fifty-five common channels were noted to be dilated. Hepaticojejunostomy was performed in 123 patients without intraoperative endoscopy. Late stone formation occurred within the IHBD in 4 of these cases and within residual segments of intrapancreatic cyst in 2 (mean age and follow-up period were 4.9 and 13.0 years, respectively). Intraoperative endoscopy was performed in 51 patients (mean age and follow-up period 3.6 and 4.3 years), and stone formation has not been observed in any patients in this group. Intraoperative cyst endoscopy is recommended as a valuable adjunct to choledochal cyst excision.
Adolescent↗