Reaction between the (3,1) isomer of Ru2(F5ap)4Cl and CN-. Synthesis, structural determination, and electrochemistry of Ru2(F5ap).
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Journal Article↗
Biomedical subjects
B Han
Publications and source records attributed to B Han.
Phosphine-induced oxidative damage in rats: attenuation by melatonin.
Phosphine (PH(3)), from hydrolysis of aluminum, magnesium and zinc phosphide, is an insecticide and rodenticide. Earlier observations on PH(3)-poisoned insects, mammals and a mammalian cell line led to the proposed involvement of oxidative damage in the toxic mechanism. This investigation focused on PH(3)-induced oxidative damage in rats and antioxidants as candidate protective agents. Male Wistar rats were treated ip with PH(3) at 2 mg/kg. Thirty min later the brain, liver, and lung were analyzed for glutathione (GSH) levels and lipid peroxidation (as malondialdehyde and 4-hydroxyalkenals) and brain and lung for 8-hydroxydeoxyguanosine (8-OH-dGuo) in DNA. PH(3) caused a significant decrease in GSH concentration and elevation in lipid peroxidation in brain (36-42%), lung (32-38%) and liver (19-25%) and significant increase of 8-OH-dGuo in DNA of brain (70%) and liver (39%). Antioxidants administered ip 30 min before PH(3) were melatonin, vitamin C, and beta-carotene at 10, 30, and 6 mg/kg, respectively. The PH(3)-induced changes were significantly or completely blocked by melatonin while vitamin C and beta-carotene were less effective or inactive. These findings establish that PH(3) induces and melatonin protects against oxidative damage in the brain, lung and liver of rats and suggest the involvement of reactive oxygen species in the genotoxicity of PH(3).
8-Hydroxy-2'-Deoxyguanosine↗
Glial cell line-derived neurotrophic factor protects against ischemia/hypoxia-induced brain injury in neonatal rat.
Ischemic/hypoxic brain damage induced in 7-day-old rats was significantly attenuated in a dose-dependent manner by intracerebral injection of glial cell line-derived neurotrophic factor (GDNF; 2 or 4 microg) within 30 min after the insult. Whereas the great majority of the vehicle-treated animals showed massive infarction involving more than 75% of the affected cerebral hemisphere, GDNF injection resulted in a remarkable reduction in both the incidence and severity of the brain damage (incidence ranging from 76% to 93% in controls to 34% to 64% in the 2.0-microg group and 7% to 29% in 4.0-microg group). The induction of immunoreactive 70-kDa heat shock protein (HSP70) in cerebral cortical neurons was also significantly reduced in GDNF-treated animals as compared to controls. The mechanisms responsible for the neuroprotective effects of GDNF remain unknown, although it has been speculated that these may be endogeneous. The higher expression of GDNF and its mRNA in developing brains may be one of the factors responsible for the relative resistance to ischemia of fetal and neonatal as opposed to adult brains. GDNF may possibly act by protecting against oxidative stress or by scavenging free radicals generated during ischemia. The results of our study strongly suggest that GDNF may prove to be an effective and potent protective agent against perinatal ischemic/hypoxic encephalopathy.
Animals↗
Application of Live Monocells from Macroalgae to Shellfish Seed Production.
Monocells were isolated from several macroalgae, Porphyra yezoensis, Undaria pinnatifida, and Laminaria japonica, by digestion with alga-tool enzymes. The monocells were then used to feed the parents or larvae of bay scallop Argopecten irradians, blood cockle Arca inflata, and abalone Haliotis discus juveniles. Results showed that the parents of bay scallop and blood cockle fed with Porphyra monocells could mature and discharge eggs and spermatozoa and their larvae could metamorphose; the survival rate of abalone juveniles fed with isolated cells from Laminaria and Undaria increased by 100% compared with that of those fed with artificial food.
Journal Article↗
Menadione-induced oxidative stress inhibits cholecystokinin-stimulated secretion of pancreatic acini by cell dehydration.
The present study evaluated the effects of free radicals generated by menadione on morphology and function of pancreatic acinar cells focusing on enzyme secretion, stimulus-secretion coupling, and cell hydration. Various experiments evaluated morphology and function of isolated rat pancreatic acinar cells exposed to menadione. Menadione instantaneously generated free radicals (luminol and deoxyribose assays) followed by a time-dependent cell injury (uptake of trypan blue). Early ultrastructural changes included vacuolization and alterations of mitochondria, endoplasmic reticulum, and nucleus. Menadione caused a rapid glutathione oxidation followed by a depletion in reduced glutathione. An increase in lipid peroxides and a depletion of adenosine triphosphate were seen only after 30-60 minutes. Menadione markedly inhibited amylase release stimulated by cholecystokinin (CCK) and carbachol and simultaneously caused cell shrinkage after a few minutes. Similar degrees of cell shrinkage induced by hyperosmolar incubation and by menadione inhibited amylase secretion to a similar extent. CCK binding and its effect on calcium and inositol 1,4,5-trisphosphate (IP3) were not affected by menadione. Menadione (without CCK) induced an instantaneous increase of intracellular calcium followed by a slow constant increase. In single cells, menadione induced calcium oscillations with a frequency lower than that seen after CCK stimulation. Some morphologic and functional alterations owing to menadione-induced oxidative stress may be caused by adenosine triphosphate and glutathione depletion, lipid peroxidation, and changes in cytosolic calcium. The marked inhibition of secretagogue-stimulated enzyme secretion owing to menadione may be mediated to a large part by cell dehydration, whereas classical steps of stimulus-secretion coupling like receptor binding, calcium release, and IP3 generation remained unchanged.
Adenosine Triphosphate↗
CCK stimulates mob-1 expression and NF-kappaB activation via protein kinase C and intracellular Ca(2+).
Supraphysiological concentrations of cholecystokinin (CCK) induce chemokine expression in rat pancreatic acini through the activation of the transcription factor NF-kappaB. In the current study, the intracellular signals involved in these pathophysiological effects of CCK were investigated. CCK induction of mob-1 expression in isolated rat pancreatic acini was blocked by the protein kinase C (PKC) inhibitors GF-109203X and Ro-32-0432 and by the intracellular Ca(2+) chelator BAPTA. CCK induced NF-kappaB nuclear translocation, and DNA binding was also blocked by GF-109203X and BAPTA. Direct activation of PKC with TPA induced mob-1 chemokine expression and activated NF-kappaB DNA binding to a similar extent as did CCK. Increasing intracellular Ca(2+) using ionomycin had no effect on mob-1 mRNA levels or NF-kappaB activity. Both CCK and TPA treatments decreased inhibitory kappaB-alpha (IkappaB-alpha) levels, whereas ionomycin had no effect. However, the effects of TPA on IkappaB-alpha degradation were less complete than for CCK. In combination, TPA and ionomycin degraded IkappaB-alpha to a similar extent as CCK. Therefore, activation of NF-kappaB and mob-1 expression by supraphysiological CCK is likely mediated by both PKC activation and elevated intracellular Ca(2+).
Animals↗
Treatment margins for prostate brachytherapy.
The purpose of this article was to determine what planned treatment margin (TM) would allow for implant-related prostate volume changes and still achieve an adequate periprostatic cancercidal dose. Twenty consecutive, unselected patients who underwent (125)I implantation (144 Gy prescription dose) were studied. The treated volume (TV) was calculated as the volume encompassed by the 144 Gy isodose distribution. A post-implant computed tomography scan was obtained the following day, using 5-mm images at every 5 mm. The distances between the prostate margin (GTV) and TV were determined by measuring the distance between the ultrasound-defined prostatic margin and the prescription isodose, perpendicular to the prostatic margin. The lateral, anterior, and posterior TM margins were determined at the base, mid-level, and apex of the prostate. The pre-implant TV was nearly twice as large as the GTV, ranging from 36 to 199 mL (median, 73 mL). The anterior, lateral, and posterior planned TMs varied substantially between patients, due to lack of a consistent policy the magnitude of the CTV and the acceptable CTV-to-TV distance. For all measurement points, the median planned treatment margin was 3 mm (range, -16 mm to 14 mm). Overall, there was only a loose correlation between pre- and post-implant treatment margins primarily due to variable, implant-related prostatic dimensional changes. Patients with a greater implant-related volume increase tended to have smaller post-implant treatment margins. The post-implant TMs were negatively correlated with dimensional changes, and the negative correlation was most marked for the anterior and posterior TMs due to predominant anterior-posterior dimensional increase. As expected, the post-implant target coverage was higher when larger planning TMs were used, but the correlation was loose due to the unpredictable, highly variable degree of implant-related volume increase. We currently are using 5-mm TMs around the GTV, as identified on pre-implant transrectal ultrasonography or computed tomography. However, the poor correlation between planned and actual post-implant TMs call into question any attempt to make a rational recommendation regarding optimal TMs.
Brachytherapy↗
[Changes of hepatic energy metabolism following partial hepatopetal blood occlusion].
OBJECTIVE: To evaluate the changes of hepatic energy metabolism by temporary occlusion of partial hepatopetal blood. METHODS: The animal mode of partial hepatopetal blood occlusion (PBO) was established without portal stasis. The hepatic energy metabolism parameters including adenosine triphosphate, respiratory control ratio, P/O ratio, and arterial ketone bodies ratio were studied following 30 min ischemia or 1, 6, and 24 h of reperfusion. The total hepatopetal blood occlusion (TBO) and sham groups served as control. RESULTS: The parameters of hepatic motochondrial function reflecting hepatic damage to ischemia-reperfusion showed different in PBO comparing with TBO group. The functional lesion was restored progressively in PBO-30 min group, but it was maintained low level in TBO-30 min group. CONCLUSION: The results suggest that it is beneficial to restoration of the hepatic energy metabolism in the ischemia-reperfusion injury by partial hepatopetal blood occlusion.
Adenosine Triphosphate↗
[Behavior response of four Leis axyridis varieties to volatiles from tea and Toxoptera aurantii].
The behavior response of the adults of four Leis axyridis varieties to kairomone from Taxoptera aurantii was determined by Y-shape olfaction instrument. The results showed that when supplied with two-two-combinations of Taxoptera aurantii, Brevicoryne brassicae and Lipaphis erysimi, tea aphids plus aphid-damaged vs. normal shoots, and aphid-damaged vs. normal shoots, Leis axyridis had a preference for tea aphids, tea aphids plus aphid-damaged tea shoots, or aphid-damaged tea shoots. There existed a Logistic curve relationship(P < 0.01) between odor source tendency rate of Leis axyridis and odor source quality, when 8-9 kinds of odor gradients including tea aphids plus aphid-damaged tea shoots, aphid-damaged tea shoots and tea aphids were used as odor sources. The tendency rates of Leis axyridis ab. bimaculata, Leis axyridis ab. conspicua and Leis axyridis var. novemdecimpunctata showed single left-tilting peak curves to the aphid number(P < 0.01). Ether and n-hexane ringes of Toxoptera aurantii body surface also showed an attraction to all varieties. Leis axyridis var. spectabilis was the most sensitive variety.
Animals↗
Invariance of brain-wave representations of simple visual images and their names.
In two experiments, electric brain waves of 14 subjects were recorded under several different conditions to study the invariance of brain-wave representations of simple patches of colors and simple visual shapes and their names, the words blue, circle, etc. As in our earlier work, the analysis consisted of averaging over trials to create prototypes and test samples, to both of which Fourier transforms were applied, followed by filtering and an inverse transformation to the time domain. A least-squares criterion of fit between prototypes and test samples was used for classification. The most significant results were these. By averaging over different subjects, as well as trials, we created prototypes from brain waves evoked by simple visual images and test samples from brain waves evoked by auditory or visual words naming the visual images. We correctly recognized from 60% to 75% of the test-sample brain waves. The general conclusion is that simple shapes such as circles and single-color displays generate brain waves surprisingly similar to those generated by their verbal names. These results, taken together with extensive psychological studies of auditory and visual memory, strongly support the solution proposed for visual shapes, by Bishop Berkeley and David Hume in the 18th century, to the long-standing problem of how the mind represents simple abstract ideas.
Adult↗
Invariance between subjects of brain wave representations of language.
In three experiments, electric brain waves of 19 subjects were recorded under several different experimental conditions for two purposes. One was to test how well we could recognize which sentence, from a set of 24 or 48 sentences, was being processed in the cortex. The other was to study the invariance of brain waves between subjects. As in our earlier work, the analysis consisted of averaging over trials to create prototypes and test samples, to both of which Fourier transforms were applied, followed by filtering and an inverse transformation to the time domain. A least-squares criterion of fit between prototypes and test samples was used for classification. In all three experiments, averaging over subjects improved the recognition rates. The most significant finding was the following. When brain waves were averaged separately for two nonoverlapping groups of subjects, one for prototypes and the other for test samples, we were able to recognize correctly 90% of the brain waves generated by 48 different sentences about European geography.
Brain↗
Structural and Thermodynamic Properties of Solutions of Butane in Aqueous Sodium Dodecyl Sulfate: A Study Using Neutron Scattering and Solubility Measurements.
The solubility of n-butane at a pressure of 1.013 bar in aqueous solutions of sodium dodecyl sulfate (SDS) has been measured over a range of concentration from below the critical micelle concentration (CMC) at about 8 mol kg(-1) to about 90 mol kg(-1) at three different temperatures. The free energy, enthalpy, and entropy of transfer of butane from water to the micelle were respectively -19.0 kJ mol(-1), 5.5 kJ mol(-1), and 80 J K(-1) mol(-1). At 68 mol kg(-1) a transition was found with a free energy of about -400 J mol(-1). Small-angle neutron experiments were used to study the effect of butane on the state of aggregation of the SDS. For each butane molecule incorporated into a micelle, the aggregation number of the SDS increased by an average of about 1.4 molecules. Thus, at 1.013 bar of butane and 50 mM SDS, where the solubility is about 1 butane to 10 SDS, the average micelle increases in size by about 20%, most of which comes from the additional SDS molecules. The aggregation behavior is qualitatively similar to that reported for hexane, heptane, and octane, but the effect seems to be larger for butane for a given volume of solute hydrocarbon. Small-angle scattering did not observe any substantial change in structure across the phase transition at 68 mol kg(-1). Copyright 1999 Academic Press.
Journal Article↗
The release of acetylcholine receptor inducing activity (ARIA) from its transmembrane precursor in transfected fibroblasts.
Acetylcholine receptor inducing activity (ARIA) is made by motoneurons and is released at the neuromuscular synapse to stimulate the synthesis of acetylcholine receptors by skeletal muscle. ARIA is derived from a transmembrane precursor (pro-ARIA) via proteolytic cleavage of the ectodomain. We studied requirements in the amino acid sequence at the cleavage site with various substitution and deletion mutations. Wild type (WT) and mutant proteins were transiently expressed in COS cells, and release of ARIA into the conditioned medium was measured by tyrosine phosphorylation of its receptor, p185, in L6 cells. Removal of all potential cleavage sites between the extracellular epidermal growth factor domain and the transmembrane domain by substitution and small deletions (<11 amino acid residues out of 21) did not significantly reduce ARIA release, whereas larger deletions abolished it. We propose that cleavage occurs independently of amino acid sequence at a short distance from the epidermal growth factor domain, unless sterically hindered by the nearby secondary structure. A mutant with shorter cytoplasmic domain ("c" isoform) released significantly less ARIA than the WT ("a" isoform), suggesting that the c isoform may be suitable for signaling through direct cell-cell contact. Alternatively, proteolytic conversion of the a isoform to the c isoform may rapidly down-regulate release of ARIA.
Amino Acid Sequence↗
A recombinant human TGF-beta1 fusion protein with collagen-binding domain promotes migration, growth, and differentiation of bone marrow mesenchymal cells.
A continuous source of osteoblasts for normal bone maintenance, as well as remodeling and regeneration during fracture repair, is ensured by the mesenchymal osteoprogenitor stem cells of the bone marrow (BM). The differentiation and maturation of osteoprogenitor cells into osteoblasts are thought to be modulated by transforming growth factors-beta (TGF-beta1 and TGF-beta2) and TGF-beta-related bone morphogenetic proteins (BMPs). To define the responses of mesenchymal osteoprogenitor stem cells to several growth factors (GFs), we cultured Fischer 344 rat BM cells in a collagen gel medium containing 0.5% fetal bovine serum for prolonged periods of time. Under these conditions, survival of BM mesenchymal stem cells was dependent on the addition of GFs. Recombinant hTGF-beta1-F2, a fusion protein engineered to contain an auxiliary collagen binding domain, demonstrated the ability to support survival colony formation and growth of the surviving cells, whereas commercial hTGF-beta1 did not. Initially, cells were selected from a whole BM cell population and captured inside a collagen network, on the basis of their survival response to added exogenous GFs. After the 10-day selection period, the surviving cells in the rhTGF-beta1-F2 test groups proliferated rapidly in response to serum factors (10% FBS), and maximal DNA synthesis levels were observed. Upon the addition of osteoinductive factors, osteogenic differentiation in vitro was evaluated by the induction of alkaline phosphatase (ALP) expression, the production of osteocalcin (OC), and the formation of mineralized matrix. Concomitant with a down-regulation of cell proliferation, osteoinduction is marked by increased ALP expression and the formation of colonies that are competent for mineralization. During the induction period, when cells organize into nodules and mineralize, the expression of OC was significantly elevated along with the onset of extracellular matrix mineralization. Differentiation of BM mesenchymal stem cells into putative bone cells as shown by increased ALP, OC synthesis, and in vitro mineralization required the presence of specific GFs, as well as dexamethasone (dex) and beta-glycerophosphate (beta-GP). Although rhTGF-beta1-F2-selected cells exhibited the capacity to mineralize, maximal ALP activity and OC synthesis were observed in the presence of rhBMPs. We further report that a novel rhTGF-beta1-F2 fusion protein, containing a von Willebrand's factor-derived collagen binding domain combined with a type I collage matrix, is able to capture, amplify, and stimulate the differentiation of a population of cells present in rat BM. When these cells are subsequently implanted in inactivated demineralized bone matrix (iDBM) and/or diffusion chambers into older rats they are able to produce bone and cartilage. The population of progenitor cells captured by rhTGF-beta1-F2 is distinct from the committed progenitor cells captured by rhBMPs, which exhibit a considerably more differentiated phenotype.
Alkaline Phosphatase↗
Effects of Chain Length and Structure of Cationic Surfactants on the Adsorption onto Na-Kaolinite.
The adsorption of a series of alkylammonium bromides (RR1N(CH3)2Br) with different chain lengths R and R1 on a nonswelling clay surface (sodium kaolinite) has been studied by microelectrophoresis and adsorption isotherms. An increase in the number of CH2 groups in the shorter alkyl chain of the double-chain surfactant, or the introduction of another kind of alkyl group (phenyl group), was found to have much less effect on the adsorption behavior than changing the length of the alkyl chain in the single-chain surfactants. It is inferred that the effective hydrophobicity of the shorter chains in these double-chain surfactants is reduced by their intramolecular association with the longer chain. Comparison of adsorption and micellization leads to an empirical quantitative description of the effects of alkyl chain length and structure on adsorption. Copyright 1999 Academic Press.
Journal Article↗
Processing of ARIA and release from isolated nerve terminals.
The neuromuscular junction is a specialized synapse in that every action potential in the presynaptic nerve terminal results in an action potential in the postsynaptic membrane, unlike most interneuronal synapses where a single presynaptic input makes only a small contribution to the population postsynaptic response. The postsynaptic membrane at the neuromuscular junction contains a high density of neurotransmitter (acetylcholine) receptors and a high density of voltage-gated Na+ channels. Thus, the large acetylcholine activated current occurs at the same site where the threshold for action potential generation is low. Acetylcholine receptor inducing activity (ARIA), a 42 kD protein, that stimulates synthesis of acetylcholine receptors and voltage-gated Na+ channels in cultured myotubes, probably plays the same roles at developing and mature motor endplates in vivo. ARIA is synthesized as part of a larger, transmembrane, precursor protein called proARIA. Delivery of ARIA from motor neuron cell bodies in the spinal cord to the target endplates involves several steps, including proteolytic cleavage of proARIA. ARIA is also expressed in the central nervous system and it is abundant in the molecular layer of the cerebellum. In this paper we describe our first experiments on the processing and release of ARIA from subcellular fractions containing synaptosomes from the chick cerebellum as a model system.
Animals↗
Sensitive detection of the binding of E2F to its promoter by exonuclease III- and BssHII-protection PCR assays.
For the non-radioactive, sensitive detection of the binding of transcription factor E2F to its binding site (E2 promoter), exonuclease III (ExoIII)- and BssHII-protection PCR assays were established. The binding of glutathione S-transferase E2F-1 (GST-E2F-1) fusion protein to its promoter protected the promoter against ExoIII- and BssHII-digestion. For the BssHII-protection PCR assay, a BssHII restriction site was made in the E2 promoter sequence by changing one base-pair next to its sequence. To detect E2F binding in ExoIII- or BssHII-protection PCR assays, the use of 3.13 fmol (5.00 ng) or 2.33 fmol (4.62 ng) of DNA (containing E2 promoters) and 0.325 microg (3.70 pmol) or 0.175 microg (2.00 pmol) of GST-E2F-1 protein, respectively, were found to be sufficient.
Carrier Proteins↗
Quantification of iNOS mRNA with reverse transcription polymerase chain reaction directly from cell lysates.
Inducible nitric oxide synthase (iNOS) is a member of a family of primary inflammatory response genes. Quantitative measurement of iNOS mRNA levels is important for the study of gene expression of this enzyme during the process of inflammation. We report here a method for quantitative measurement of iNOS mRNA levels with rtPCR directly from cells lysed with a single step phenol/chloroform/ether extraction. Using a mouse macrophage cell line, J774.2, which expresses iNOS mRNA upon LPS + IFN-gamma treatment as the model, the effects of the extraction on iNOS mRNA recovery and cytosolic RNase removal have been studied. The cells are lysed and RNases denatured and removed by phenol/chloroform extraction. Trace amounts of the phenol partitioned in the samples are then removed by ether extraction. After the extraction, the samples can be used directly for reverse transcription and PCR without further purification of RNA. The recovery of specific mRNA is not affected by the extraction procedure and externally added iNOS cRNA shows no degradation by the extracted cell lysates. Measurement of iNOS mRNA with this procedure is linear using serially double-diluted cells in the range from 94 to 6000 cells. The efficiencies of rtPCR of iNOS wild-type and deletion cRNAs are also compared in our study. By controlling the molecular size of the deletion construct to within 10% of that of the wild type and maintaining PCR cycling below 25 cycles, the rtPCR efficiencies of iNOS wild type and deletion are identical. The detection of rtPCR products is enhanced by hybridization with specific probes. Under these conditions, iNOS mRNA concentration can directly be calculated from the internal standard in each tube without a standard curve. We conclude that our procedure provides an accurate method for quantitative measurement of iNOS mRNA from limited amount of cells without complete RNA isolation.
Animals↗