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Biomedical subjects

K Nishijima

Publications and source records attributed to K Nishijima.

At least 19 recordsLinked to original sources

In vivo evaluation of ocular inflammatory responses in experimental diabetes.

AIMS: Diabetic patients may have abnormal inflammatory reactions to foreign or endogenous stimuli. This study was designed to evaluate inflammatory reactions in the diabetic eye through retinal leucocyte dynamics in the inflamed eyes of diabetic rats. METHODS: Three weeks after diabetes induction in Long-Evans rats, endotoxin induced uveitis was produced by footpad injection of lipopolysaccharide (LPS). After LPS injection, leucocyte behaviour was evaluated in vivo by acridine orange digital fluorography. RESULTS: The number of rolling leucocytes increased in a biphasic manner at 12 hours and 48 hours. The number of leucocytes accumulating in the retina reached a peak at 72 hours. The maximal numbers of rolling and accumulating leucocytes in the diabetic retina decreased by 56.3% (p<0.01) and 46.7% (p<0.0001), respectively, compared with the non-diabetic retina. The levels of mRNA expression of adhesion molecules in the retina, which were upregulated after LPS injection, were also lower in diabetic rats than in non-diabetic rats. CONCLUSION: This study is the first to show that endotoxin induced inflammation is disturbed in the diabetic eye, based on evidence that the leucocyte-endothelial cell interactions stimulated by LPS were suppressed in the diabetic retina. These findings support the theory that ocular inflammatory reactions are impaired in diabetic patients.

Animals↗

Transverse fundal uterine incision in a patient with placenta increta.

In cases with placenta accreta occurring on the previous cesarean scar, a longitudinal incision is generally appropriate. However, the placenta may prevent both a longitudinal and lower transverse incision. We report a case of placenta increta on the previous cesarean scar, and discuss the role of transverse fundal uterine incision.

Adult↗

Preparation and pharmaceutical evaluation for clinical application of high specific activity S-(-)[11C]CGP-12177, a radioligand for beta-adrenoreceptors.

BACKGROUND: Although S-(-)[C]CGP-12177 is a useful positron emission tomography (PET) ligand for beta-adrenoreceptors, the difficulty in radiolabelling the compound has prevented its extensive clinical application. Recently, we have developed a simple synthesis method for S-(-)[C]CGP-12177. In the present study, we attempted to prepare S-(-)[C]CGP-12177 with a high specific activity for intravenous injection which is feasible for the clinical evaluation of beta-adrenoreceptors. METHODS: The [C]methane produced during irradiation of a N2--H2 (95/5) mixture with an 18 MeV proton beam (20 microA, 30 min) was chlorinated using Cl2 to yield [C]carbon tetrachloride. S-(-)[C]CGP-12177 was synthesized by reacting the diamino precursor with [C]phosgene produced by oxidizing [C]carbon tetrachloride on a Fe--Fe2O3 column. The product was purified by using reversed phase, high-performance liquid chromatography (RP-HPLC) and the radioactive fraction containing S-(-)[C]CGP-12177 was collected and evaporated to dryness. S-(-)[C]CGP-12177 dissolved in physiological saline was sterilized through a 0.22 microm membrane filter. The radiochemical purity and the mass of the compound were determined with RP-HPLC. The residual organic solvents were determined with GC. Tests for sterility and the presence of bacterial endotoxins were also performed. RESULTS: S-(-)[C]CGP-12177 for intravenous injection was prepared in 25 min after the end of bombardment with a yield of 1.5+/-0.2 GBq. Specific activity was found to be 385.4+/-133.0 GBq/ micromol at the end of synthesis (EOS) (n=3). Radiochemical purity was found to be more than 99%. Toluene was not detected in the solution. The ethanol concentration was determined to be 60.3+/-52.5 ppm. Tests for sterility and bacterial endotoxins showed negative results. CONCLUSION: We successfully prepared S-(-)[C]CGP-12177 formulated for intravenous injection with high purity and high specific activity, which is feasible for the clinical evaluation of beta-adrenoreceptors.

Drug Evaluation, Preclinical↗

Oxidative stress-induced DNA damage in the synovial cells of the temporomandibular joint in the rat.

Synovial hyperplasia is a feature of degenerative temporomandibular joint (TMJ) disease. However, the mechanism by which hyperplasia progresses in the TMJ is unknown. Based on the hypothesis that the oxidative stress generated by mechanical loading causes degenerative changes in the TMJ synovium, we investigated the generation of the highly reactive species, peroxynitrite, and the occurrence of DNA damage in the synovium. After condylar hypermobility of rat TMJs, a marker of peroxynitrite, nitrotyrosine, was localized to the nuclei and cytoplasm of the synovial lining cells and fibroblasts in synovitis-induced TMJ. DNA single-strand breaks were found in the nuclei of the synovial cells only after enzyme treatment, whereas DNA double-strand breaks were not detected. These findings indicate that condylar hypermovement induces the proliferation of synovial cells, and suggest that oxidative stress leads to the progression of synovial hyperplasia via DNA damage of the synovial cells in TMJs after mechanical loading.

Animals↗

Suppressive effects of selectin inhibitor SKK-60060 on the leucocyte infiltration during endotoxin induced uveitis.

BACKGROUND: It is well known that selectin is involved in the development of endotoxin induced uveitis (EIU), and has a major role in leucocyte infiltration. Recently, a novel selectin inhibitor (SKK-60060) that can block P and L selectins in vitro has been developed. This study was designed to investigate the anti-inflammatory effects of SKK-60060 on the inflammatory reaction during EIU in rats by studying leucocyte-endothelium interactions. METHODS: EIU was induced in Lewis rats by footpad injection of lipopolysaccharide (LPS). SKK-60060 was administered 15 minutes before LPS injection, and its suppressive effects on inflammatory leucocyte behaviour were evaluated in vivo with acridine orange digital fluorography; the diameters of retinal arteries and veins were also measured. After these studies, aqueous humour was collected to evaluate leucocyte infiltration and protein leakage. RESULTS: After LPS injection, rolling leucocytes were observed in major retinal veins, followed by leucocyte infiltration into the vitreous cavity. Following treatment with SKK-60060, leucocyte rolling was significantly inhibited in the retinal veins (p <0.01), and subsequent leucocyte infiltration into the vitreous cavity was also significantly suppressed (p <0.01). Retinal vasodilation was also substantially suppressed in SKK-60060 treated rats (p <0.01). Similarly, leucocyte infiltration and protein leakage into the aqueous humour were reduced significantly by SKK-60060 (p <0.01). CONCLUSIONS: SKK-60060 treatment significantly inhibited the inflammatory reaction induced by LPS. Its inhibitory effects on P and L-selectin resulted in suppression of leucocyte infiltration and the subsequent inflammatory reaction caused by accumulated leucocytes. The current findings suggest that SKK-60060 may be useful in the management of uveitis.

Animals↗

NF-kappaB activation and iNOS expression in the synovial membrane of rat temporomandibular joints after induced synovitis.

NF-kappaB plays a pivotal role in pathogenesis in general arthritis. However, the participation of NF-kappaB in inflammation of the temporomandibular joint (TMJ) is poorly understood. We examined NF-kappaB expression in rat TMJs with synovitis induced by condyle hypermobility. By immunohistochemistry, NF-kappaB immunoreactivity was found mainly in the cytoplasm, not the nucleus, of the synovial lining cells of induced-synovitis and control TMJs. Southwestern histochemistry, a new method for detecting transcription factors, showed greater NF-kappaB expression in the nucleus of the synovial lining cells in the hypertrophic synovium than in control synovium. Increased numbers of the synovial lining cells with immunoreactivity for inducible nitric oxide synthase (iNOS), which is transcriptionally regulated by NF-kappaB, were also seen in the inflamed synovium. These findings indicate that excess mechanical stress increases NF-kappaB activation in the TMJ and suggest that active NF-kappaB is involved in the progression of TMJ inflammation.

Animals↗

The acceleration of cosmic-ray protons in the supernova remnant RX J1713.7-3946.

Protons with energies up to approximately 10(15) eV are the main component of cosmic rays, but evidence for the specific locations where they could have been accelerated to these energies has been lacking. Electrons are known to be accelerated to cosmic-ray energies in supernova remnants, and the shock waves associated with such remnants, when they hit the surrounding interstellar medium, could also provide the energy to accelerate protons. The signature of such a process would be the decay of pions (pi(0)), which are generated when the protons collide with atoms and molecules in an interstellar cloud: pion decay results in gamma-rays with a particular spectral-energy distribution. Here we report the observation of cascade showers of optical photons resulting from gamma-rays at energies of approximately 10(12) eV hitting Earth's upper atmosphere, in the direction of the supernova remnant RX J1713.7-3946. The spectrum is a good match to that predicted by pion decay, and cannot be explained by other mechanisms.

Journal Article↗

Spontaneous recurrence of methamphetamine-induced paranoid-hallucinatory states in female subjects: susceptibility to psychotic states and implications for relapse of schizophrenia.

In this study, we examined the relationship between increased sensitivity to stress associated with noradrenergic hyperactivity and dopaminergic changes, and susceptibility to subsequent spontaneous recurrences of methamphetamine (MAP) psychosis (i.e., flashbacks). The subjects were 81 physically healthy females. Plasma monoamine metabolite levels were assayed in: 19 flashbackers, of whom 11 experienced a single flashback and 8 exhibited subsequent flashbacks; 20 non-flashbackers with a history of MAP psychosis; 8 subjects with persistent MAP psychosis; and 23 MAP users and 11 non-user controls. All 19 flashbackers had undergone frightening and stressful experiences during previous MAP use. Mild psychosocial stressors then triggered their flashbacks. During flashbacks, plasma norepinephrine levels increased, with a small increase in plasma levels of 3-methoxytyramine, which is an index of dopamine release. Among the 19 flashbackers, the 8 with subsequent episodes had increased NE levels and slightly increased 3-methoxytyramine levels, while the 11 with a single episode displayed small increases in norepinephrine and 3-methoxytyramine levels. Thus, noradrenergic hyperactivity and increased dopamine release in response to mild psychosocial stressors may be responsible for the development of flashbacks. Robust noradrenergic hyperactivity with slightly increased DA release in response to mild stress may induce susceptibility to subsequent flashbacks. Flashbacks and schizophrenia may share the pathophysiology of susceptibility to recurrence of paranoid-hallucinatory states such as stress sensitization, and also noradrenergic hyperactivity and enhanced DA release. Thus, flashbacks may provide an appropriate model of susceptibility to paranoid-hallucinatory states of schizophrenia. The model psychosis is a potential tool for validating basic neurobiological concepts thought to be related to the schizophrenia. A better understanding of the neurobiological mechanisms of susceptibility to recurrence could provide useful information in the development of strategies for preventing relapse.

Adult↗

Susceptibility to subsequent episodes of spontaneous recurrence of methamphetamine psychosis.

We examine susceptibility to subsequent spontaneous recurrences of methamphetamine psychosis (i.e. flashbacks) in 11 flashbackers with a single episode and in nine flashbackers with subsequent episodes. All had undergone frightening stressful experiences during previous MAP use. Mild psychosocial stressors then triggered flashbacks. During flashbacks, the nine flashbackers with subsequent episodes had more markedly increased norepinephrine levels, with slightly increased 3-methoxytyramine levels. The duration of imprisonment in this subgroup approached significantly long levels than in the 11 flashbackers with a single episode. Robust noradrenergic hyperactivity with slightly increased dopamine release may therefore predict subsequent flashbacks. Longer exposure to distressing situations may also contribute to robust noradrenergic hyperactivity.

3,4-Dihydroxyphenylacetic Acid↗

Complete genome sequence of an aerobic thermoacidophilic crenarchaeon, Sulfolobus tokodaii strain7.

The complete genomic sequence of an aerobic thermoacidophilic crenarchaeon, Sulfolobus tokodaii strain7 which optimally grows at 80 degrees C, at low pH, and under aerobic conditions, has been determined by the whole genome shotgun method with slight modifications. The genomic size was 2,694,756 bp long and the G + C content was 32.8%. The following RNA-coding genes were identified: a single 16S-23S rRNA cluster, one 5S rRNA gene and 46 tRNA genes (including 24 intron-containing tRNA genes). The repetitive sequences identified were SR-type repetitive sequences, long dispersed-type repetitive sequences and Tn-like repetitive elements. The genome contained 2826 potential protein-coding regions (open reading frames, ORFs). By similarity search against public databases, 911 (32.2%) ORFs were related to functional assigned genes, 921 (32.6%) were related to conserved ORFs of unknown function, 145 (5.1%) contained some motifs, and remaining 849 (30.0%) did not show any significant similarity to the registered sequences. The ORFs with functional assignments included the candidate genes involved in sulfide metabolism, the TCA cycle and the respiratory chain. Sequence comparison provided evidence suggesting the integration of plasmid, rearrangement of genomic structure, and duplication of genomic regions that may be responsible for the larger genomic size of the S. tokodaii strain7 genome. The genome contained eukaryote-type genes which were not identified in other archaea and lacked the CCA sequence in the tRNA genes. The result suggests that this strain is closer to eukaryotes among the archaea strains so far sequenced. The data presented in this paper are also available on the internet homepage (http://www.bio.nite.go.jp/E-home/genome_list-e.html/).

Archaeal Proteins↗

Production of transgenic quails with high frequency of germ-line transmission using VSV-G pseudotyped retroviral vector.

We report here the production of transgenic quails using a replication-defective pantropic retroviral vector based on Moloney murine leukemia virus (MoMLV) pseudotyped with vesicular stomatitis virus G protein (VSV-G). The retroviral vector was injected into laid quail embryos at the blastodermal stage, and the embryos were incubated to hatch to produce G(0) transgenic quails. Among 134 embryos subjected to viral injection, 37 hatched. The viral vector sequence was detected in the tissues of all G(0) quails. The germ-line transmission efficiency of G(0) quails mated with nontransgenic quails was more than 80% on average. Southern blot analysis revealed that the G(1) transgenic progeny had one to three copies of the transgene. The expression of vector-encoded neomycin-resistance gene under the control of the Rous sarcoma virus (RSV) promoter was observed in several tissues including heart and muscle of both G(1) and G(2) transgenic offspring. Due to the high frequency of germ-line transmission, this method may markedly facilitate the production of transgenic avian.

Animals↗

Comparison in localization between cystatin C and cathepsin K in osteoclasts and other cells in mouse tibia epiphysis by immunolight and immunoelectron microscopy.

We compared the distribution of a cysteine proteinase inhibitor, cystatin C, with that of cathepsin K in osteoclasts of the mouse tibia by immunolight and immunoelectron microscopy. Light microscopically, strong immunoreactivity for cystatin C was found extracellularly along the resorption lacuna and intracellularly in the organelles of osteoclasts. In serial sections, various patterns of cystatin C and cathepsin K localization were seen, specifically: (1) some resorption lacuna were positive for both cystatin C and cathepsin K; (2) others were positive for either cystatin C or cathepsin K, but not both; and (3) some lacuna were negative for both. In osteoclasts, the localization of cystatin C was similar to that of cathepsin K. Furthermore, cystatin C immunoreactivity was detected in preosteoclasts and osteoblasts, whereas cathepsin K was seen only in preosteoclasts. Electron microscopically, cystatin C immunoreactive products were found in the rough endoplasmic reticulum (ER), Golgi apparatus, vesicles, granules, and vacuoles of osteoclasts. These cystatin C-positive vesicles had fused or were in the process of fusion with the ampullar vacuoles (extracellular spaces) containing cystatin C-positive, fragmented, fibril-like structures. The extracellular cystatin C was deposited on and between the cytoplasmic processes of ruffled borders, and on and between type I collagen fibrils. In the basolateral region of osteoclasts, cystatin C-positive vesicles and granules also fused with vacuoles that contained cystatin C-positive or negative fibril-like structures. These results indicate that osteoclasts not only synthesize and secrete cathepsin K from the ruffled border into the bone resorption lacunae, but also a cysteine proteinase inhibitor, cystatin C. Therefore, it is suggested that cystatin C regulates the degradation of bone matrix by cathepsin K, both extracellularly and intracellularly.

Animals↗

Population pharmacokinetic analysis of cisplatin and its metabolites in cancer patients: possible misinterpretation of covariates for pharmacokinetic parameters calculated from the concentrations of unchanged cisplatin, ultrafiltered platinum and total platinum.

BACKGROUND: Usually, total and filtered platinum concentrations in plasma are monitored after cisplatin administration. However, these concentrations represent a mixture of unchanged cisplatin and metabolites. In this work, we studied population pharmacokinetic analysis based on these platinum concentrations. METHODS: Twenty-seven patients (23 males, four females) were administered cisplatin (60-100 mg/m2) with intravenous constant infusion for 90 min. Blood samples were taken at about three points per patient. The concentrations of cisplatin and platinum in the plasma were determined by high-performance liquid chromatography and atomic absorption spectrometry, respectively. Population pharmacokinetic analysis was performed using the program NONMEM (Version V) with the one- or two-compartment model with zero-order infusion. RESULTS: The clearance and volume of distribution for all platinum species studied were significantly related to the body surface area of the patients. Only the clearance of filtered platinum was significantly related to urinary N-acetyl-beta-D-glucosaminidase and the other covariates were not related to these pharmacokinetic parameters with respect to unchanged cisplatin and total platinum concentrations. CONCLUSION: The dosage regimen based on the filtered platinum concentration which is usually monitored may result in possible misinterpretation because the detected covariate is different between unchanged cisplatin and filtered platinum.

Aged↗

Acid-catalyzed photoreaction of 6-chloro-1,3-dimethyluracil and mesitylene: formation of photocycloadducts and their characterization.

In contrast to the previously reported short time required (1 h) for photolysis of 6-chloro-1,3-dimethyluracil (6-CIDMU) and mesitylene, in the presence of TFA, resulting in two major products: 1,3,6,8,10-pentamethylcyclooctapyrimidine derivative (1d), and diazapentacyclo[6.4.0.0(1,3).0(2,5).0(4,8)]dodecane (2c), prolonged irradiation (18h) of this same mixture yields novel pentalenopyrimidine derivatives, including diazapentacyclo[6.4.0.0(1,3).0(2,6).0(4,8)]dodecane (3c).

Acids↗

Electrocyclic rearrangement of pentamethylcyclooctapyrimidine-2,4-diones: reaction pathway into a 9,11-diazapentacyclo-[6.4.0.0(1,3).0(2,5).0(4,8)]dodecane system and a 9,11-diazapentacyclo [6.4.0.0(1,3).0(2,6).0(4,8)]dodecane system.

Photolysis of 6-chloro-1,3-dimethyluracil and mesitylene in the presence of trifluoroacetic acid (TFA) at low temperature gave 1,3,5,7,9- and 1,3,6,8,10-pentamethylcyclooctapyrimidine-2,4-diones (1b, 1c). Sequential photoreaction of the former (1b) resulted in the formation of 9,11-diazapentacyclo[6.4.0.0(1,3).0(2,5).0(4,8)]dodecane-2,4-dione (2b) by way of 9-exo-methylene derivative (7b) and cyclobutaquinazoline (8b). On the other hand, UV-irradiation of 1c led to the bond shift isomer (5c) whose photolysis in the presence of TFA gave rise to the formation of the [6.4.0.0(1,3).0(2,6).0(4,8)]dodecane isomer (3c).

Journal Article↗