Chromium-catalyzed cyclopropanation of alkenes with bromoform in the presence of 2,3,5,6-tetramethyl-1,4-bis(trimethylsilyl)-1,4-dihydropyrazine.

Chromium-catalyzed cyclopropanation of alkenes with bromoform was achieved to produce the corresponding bromocyclopropanes. In this catalytic cyclopropanation, an organosilicon reductant, 2,3,5,6-tetramethyl-1,4-bis(trimethylsilyl)-1,4-dihydropyrazine (1a), was indispensable for reducing CrCl3(thf)3 to CrCl2(thf)3, as well as for in situ generation of (bromomethylidene)chromium(iii) species from (dibromomethyl)chromium(iii) species. The (bromomethylidene)chromium(iii) species are proposed to react spontaneously with alkenes to give the corresponding bromocyclopropanes. This catalytic cyclopropanation was applied to various olefinic substrates, such as allyl ethers, allyl esters, terminal alkenes, and cyclic alkenes.

Metal-Free Deoxygenation and Reductive Disilylation of Nitroarenes by Organosilicon Reducing Reagents.

A metal-free deoxygenation and reductive disilylation of nitroarenes was achieved using N,N'-bis(trimethylsilyl)-4,4'-bipyridinylidene (1) under mild and neutral reaction conditions, and a broad functional group tolerance was possible in this reaction. Mono-deoxygenation, giving a synthetically valuable N,O-bis(trimethylsilyl)phenylhydroxylamine (7 a) as a readily available and safe phenylnitrene source from nitrobenzene, and double-deoxygenation, giving N,N-bis(trimethylsilyl)anilines 8, were easily controlled by varying the amounts of 1 and reaction temperature as well as adding dibenzothiophene (DBTP). Reaction of 2-arylnitrobenzenes with 1 resulted in the formation of the corresponding carbazoles 14 via in situ-generated phenylnitrene species derived by thermolysis of N,O-bis(trimethylsilyl)phenylhydroxylamines 7, followed by their subsequent intramolecular C-H insertion. In addition, the intramolecular N-N coupling reaction proceeded in the reduction of 2,2'-dinitrobiphenyl derivatives by 1, giving the corresponding benzo[c]cinnolines.

White noise analysis for the correlation-type elementary motion detectors with half-wave rectifiers.

The motion detection mechanism of insects has been attracted attention of many researchers. Several motion-detection models have been proposed on the basis of insect visual system studies. Here, we examine two models, the Hassenstein-Reichardt (HR) model and the two-detector (2D) model. We analytically obtain the mean and variance of the stationary responses of the HR and the 2D models to white noise, and we derive the signal-to-fluctuation-noise ratio (SFNR) to evaluate encoding abilities of the two models. Especially when analyzing the 2D model, we calculate higher-order cumulants of a rectified Gaussian. The results show that the 2D model robustly works almost as well as the HR model in several sets of parameters estimated on the basis of experimental data.

Metathesis cleavage of an N[double bond, length as m-dash]N bond in benzo[c]cinnolines and azobenzenes by triply-bonded ditungsten complexes.

A metathesis reaction of a W[triple bond, length as m-dash]W bond and an N[double bond, length as m-dash]N bond was observed by reacting a W-W triply-bonded W(iii)2 complex, (tBuO)3W[triple bond, length as m-dash]W(OtBu)3 (1), with benzo[c]cinnoline derivatives to form biphenyl-linked dinuclear (imido)tungsten complexes 2-4. When azobenzene was used as the substrate, a trans to cis isomerization induced by blue-LED light was essential prior to the metathesis cleavage of the N[double bond, length as m-dash]N bond by the W[triple bond, length as m-dash]W bond of (Me2N)2(TfO)W[triple bond, length as m-dash]W(OTf)(NMe2)2 (6), affording the corresponding imido-bridged dinuclear tungsten complexes 7-9.

Structural and Electronic Noninnocence of α-Diimine Ligands on Niobium for Reductive C-Cl Bond Activation and Catalytic Radical Addition Reactions.

A d0 niobium(V) complex, NbCl3(α-diimine) (1a), supported by a dianionic redox-active N,N'-bis(2,6-diisopropylphenyl)-1,4-diaza-2,3-dimethyl-1,3-butadiene (α-diimine) ligand (ene-diamido ligand) served as a catalyst for radical addition reactions of CCl4 to α-olefins and cyclic alkenes, selectively affording 1:1 radical addition products in a regioselective manner. During the catalytic reaction, the α-diimine ligand smoothly released and stored an electron to control the oxidation state of the niobium center by changing between an η4-(σ2,π) coordination mode with a folded MN2C2 metallacycle and a κ2-(N,N') coordination mode with a planar MN2C2 metallacycle. Kinetic studies of the catalytic reaction elucidated the reaction order in the catalytic cycle: the radical addition reaction rate obeyed first-order kinetics that were dependent on the concentrations of the catalyst, styrene, and CCl4, while a saturation effect was observed at a high CCl4 concentration. In the presence of excess amounts of styrene, styrene coordinated in an η2-olefinic manner to the niobium center to decrease the reaction rate. No observation of oligomers or polymers of styrene and high stereoselectivity for the radical addition reaction of CCl4 to cyclopentene suggested that the C-C bond formation proceeded inside the coordination sphere of niobium, which was in good accordance with the negative entropy value of the radical addition reaction. Furthermore, reaction of 1a with (bromomethyl)cyclopropane confirmed that both the C-Br bond activation and formation proceeded on the α-diimine-coordinated niobium center during transformation of the cyclopropylmethyl radical to a homoallyl radical. With regard to the reaction mechanism, we detected and isolated NbCl4(α-diimine) (6a) as a transient one-electron oxidized species of 1a during reductive cleavage of the C-X bonds; in addition, the monoanionic α-diimine ligand of 6a adopted a monoanionic canonical form with selective one-electron oxidation of the dianionic ene-diamido form of the ligand in 1a.

Synthesis and Characterization of Paramagnetic Tungsten Imido Complexes Bearing α-Diimine Ligands.

Tungsten imido complexes bearing a redox-active ligand, such as N,N'-bis(2,6-diisopropylphenyl)-1,4-diaza-2,3-dimethyl-1,3-butadiene (L1), N,N'-bis(2,6-diisopropylphenyl)-1,4-diaza-1,3-butadiene (L2), and 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (L3), were prepared by salt-free reduction of W(═NC6H3-2,6-(i)Pr2)Cl4 (1) using 1-methyl-3,6-bis(trimethylsilyl)-1,4-cyclohexadiene (MBTCD) followed by addition of the corresponding redox-active ligands. In the initial stage, reaction of W(═NC6H3-2,6-(i)Pr2)Cl4 with MBTCD afforded a tetranuclear W(V) imido cluster, [W(═NC6H3-2,6-(i)Pr2)Cl3]4 (2), which served as a unique precursor for introducing redox-active ligands to the tungsten center to give the corresponding mononuclear complexes with a general formula of W(═NC6H3-2,6-(i)Pr2)Cl3(L) (3, L = L1; 4, L = L2; and 6, L = L3). X-ray analyses of complexes 3 and 6 revealed a neutral coordination mode of L1 and L3 to the tungsten in solid state, while the electron paramagnetic resonance (EPR) spectra of 3 and 4 clarified that a radical was predominantly located on the tungsten center supported by neutral L1 or L2, and the EPR spectra of complex 6 indicated that a radical was delocalized over both the tungsten center and the monoanionic redox-active ligand L3.

Noise-robust recognition of wide-field motion direction and the underlying neural mechanisms in Drosophila melanogaster.

Appropriate and robust behavioral control in a noisy environment is important for the survival of most organisms. Understanding such robust behavioral control has been an attractive subject in neuroscience research. Here, we investigated the processing of wide-field motion with random dot noise at both the behavioral and neuronal level in Drosophila melanogaster. We measured the head yaw optomotor response (OMR) and the activity of motion-sensitive neurons, horizontal system (HS) cells, with in vivo whole-cell patch clamp recordings at various levels of noise intensity. We found that flies had a robust sensation of motion direction under noisy conditions, while membrane potential changes of HS cells were not correlated with behavioral responses. By applying signal classification theory to the distributions of HS cell responses, however, we found that motion direction under noise can be clearly discriminated by HS cells, and that this discrimination performance was quantitatively similar to that of OMR. Furthermore, we successfully reproduced HS cell activity in response to noisy motion stimuli with a local motion detector model including a spatial filter and threshold function. This study provides evidence for the physiological basis of noise-robust behavior in a tiny insect brain.

[A case in which dihydropyrimidine dehydrogenase deficiency was strongly suspected during adjuvant chemotherapy with capecitabine for colon cancer].

Severe toxicity in patients with a deficiency of dihydropyrimidine dehydrogenase(DPD), an enzyme that reduces fluoropyrimidine, is very rare, and reports on this condition are few. Accordingly, diagnosis is very difficult. The patient was 70-year-old man who was admitted for adjuvant chemotherapy with capecitabine(3,600mg/day)for rectal cancer. He was admitted to our hospital because of severe oral mucositis(grade 3)and hand-foot syndrome(grade 3). After hospitalization, he experienced complications with neutropenia(grade 4)and thrombocytopenia(grade 4). The patient died 25 days after the onset of chemotherapy. Despite the measurement of the DPD value in mononuclear cells of peripheral blood and urophanic uracil and dihydrouracil, we were unable to diagnose DPD deficiency. However, we suspected a partial deficiency of DPD on the basis of the clinical course.

[A case of primary adenocarcinoma of small intestine responding to XELOX chemotherapy and leading to a partial metabolic response].

We report a case of adenocarcinoma of the small intestine responding to XELOX chemotherapy, leading to a partial metabolic response(PMR). The patient was a 58-year-old male with multiple peritoneal dissemination of adenocarcinoma of the small intestine. Chemotherapy with XELOX(L-OHP 130 mg/m² on day 1 , and capecitabine 1,000 mg/m2 on days 1-14)was performed. After 4 courses, a significant tumor reduction was obtained. This case suggests that chemotherapy with XELOX is a potential regimen for small intestinal adenocarcinoma.

[A case of resected rectal cancer with hepatic node and multiple liver metastases effectively treated by preoperative modified FOLFOX6 and sLV5FU2 chemotherapy].

A 55-year-old male had complained of melena.Colonoscopy revealed a type 2 tumor at the rectum.CT demonstrated hepatic lymph nodes and multiple liver metastases(stage IV).Low anterior resection was performed(tub2, RsRa, circ, type 2, pSS, pN1, sH3, cHN1, sP0, cM0: fstage IV).The patient was treated with mFOLFOX6 and sLV5FU2 after operation.CT revealed a partial response after 14 courses of systemic chemotherapy.sLV5 FU2 therapy was converted to capecitabine because he experienced bone marrow suppression.CT showed that the liver metastases had enlarged but the hepatic lymph nodes disappeared.Right portal vein embolization was performed.After 4 weeks, right hepatectomy and hepatic lymph node dissection were performed.Preoperative chemotherapy with mFOLFOX6 seems beneficial as a neoadjuvant chemotherapy for hepatic lymph node-positive advanced colorectal cancer.

[A case of early poorly-differentiated neuroendocrine carcinoma of stomach].

A 45-year-old male was admitted to our hospital complaining of anemia. Gastric endoscopy showed a type IIa+IIc tumor at the anterior wall of the gastric angle. Based on the pathology of the biopsy specimen, poorly-differentiated adenocarcinoma was diagnosed. Computed tomography scans showed regional lymph node swelling. Distal gastrectomy with a D2 lymph node dissection was performed. On pathology, the tumor was immunohistochemically positive for chromogranin A and synaptophysin. The Ki67 index was 70%. The tumor was diagnosed as poorly-differentiated neuroendocrine carcinoma of the stomach. He was treated with S-1 and CPT-11. Neuroendocrine cell carcinoma of the stomach is rare and usually has a very poor prognosis. Thus, we are reporting this case of early poorly-differentiated neuroendocrine carcinoma of the stomach that was curatively resected and had 12-month survival without recurrence.

[A case of gastric cancer with peritoneal dissemination who achieved long survival by successive treatments with S-1 in combination with CDDP, paclitaxel and irinotecan].

The patient was a 63-year-old male with multiple peritoneal disseminations of advanced gastric cancer. He underwent chemotherapy with a combination of S-1 120 mg/day (3 weeks administration and 2 weeks rest) and cisplatin (CDDP) 60 mg/m(2) (day 8). After 3 courses of this regimen, CT revealed no evidence of ascites. He then underwent laparatomy. Peritoneal dissemination appeared, and the findings were sT3, N0, H0, P1, CY1, M1(PLE), sStage IV. A bypass operation was performed. As second-line chemotherapy, he received combination chemotherapy with S-1 and paclitaxel (PTX) 60 mg/m(2) (div), 20 mg/m(2) ( ip) (day 1, 8). However, he complained of ascites after 16 courses. We tried weekly administration of PTX and tri-weekly administration of irinotecan (50 mg/m(2)) with S-1. This treatment was successfully continued for 20 courses. The adverse effect was anemia (grade 2). He died two years eight months after surgery. The chemotherapy with S-1/CDDP, S-1/PTX, and S-1/PTX/irinotecan was thought to be effective for advanced gastric cancer with peritoneal dissemination.

[A case of stage IV AFP producing cecal cancer responding to mFOLFOX6 leading to a partial response].

We report a case of stage IV AFP producing cecal cancer responding to mFOLFOX6 leading to a partial response. The patient was a 72-year-old female with multiple liver metastases of cecal cancer. She underwent a right hemicolectomy and right salpingo-oophorectomy in a non-curative resection. Final findings revealed cecal cancer, type 3, 60 x 55 mm, pSI (right ovary), pN3, sH3, sP0, cM0, fStage IV, respectively. After surgery, chemotherapy with mFOLFOX6 was performed. After 4 courses, a significant tumor reduction (PR) was obtained. She died 1 year 2 months after surgery. This case suggests that chemotherapy with mFOLFOX6 is a potential regimen for AFP producing colon cancer.

A newly developed bioartificial pancreas successfully controls blood glucose in totally pancreatectomized diabetic pigs.

Construction of a safe and functional bioartificial pancreas (BAP) that provides an adequate environment for islet cells may be an important approach to treating diabetic patients. Various types of BAP devices have been developed, but most of them involve extravascular implantation of islets in microcapsules or diffusion chambers. These devices have poor diffusive exchange between the islets and blood, and often rupture. To overcome these problems, we developed a new type of BAP composed of polyethylene-vinyl alcohol (EVAL) hollow fibers that are permeable to glucose and insulin and a poly-amino-urethane-coated, non-woven polytetrafluoroethylene (PTFE) fabric that allows cell adhesion. Porcine islets attached to the surface of the PTFE fabric, but not to the surface of the EVAL hollow fibers, allowing nutrient and oxygen exchange between blood flowing inside the fibers and cells outside. We inoculated this BAP with porcine islets and connected it to the circulation of totally pancreatectomized diabetic pigs. We found that blood glucose levels were reduced to a normal range and general health was improved, resulting in longer survival times. In addition, regulation of insulin secretion from the BAP was properly controlled in response to glucose both in vitro and in vivo. These results indicate that our newly developed BAP may be a potential therapy for the treatment of diabetes in humans.

Determination of bromide in whole blood and urine from humans using gas chromatography-mass spectrometry.

We devised a sensitive and simple method for determination of bromide in whole blood and urine from humans using gas chromatography-mass spectrometry. Bromide was alkylated with pentafluorobenzyl p-toluenesulphonate in the mixture of acetone and phosphate buffer (pH 6.8). The derivative obtained was analyzed using gas chromatography-mass spectrometry with the positive-ion EI mode. The lower limit of detection for the compound was 1 mg/l. The calibration curve for bromide was linear over the concentration range from 2 to 100 mg/l. With use of this method, levels of bromide in whole blood and urine were determined in cases of poisoning by inhaled brominated hydrocarbons.

Development of a porcine model of type 1 diabetes by total pancreatectomy and establishment of a glucose tolerance evaluation method.

PURPOSE: To develop and evaluate the efficacy of diabetes-targeted cell therapies in humans, a reliable model in larger animals is highly desirable. This article reports the surgical technique of total pancreatectomy in pigs and the biochemical analysis of the characteristics of totally pancreatectomized pigs. METHODS: Surgical total pancreatectomy was conducted in 23 pigs. Blood glucose, insulin, biochemistries, activity index, and intravenous glucose tolerance test (IVGTT) were examined to assess the pathophysiological profiles of diabetic pigs. RESULTS: A total of 14 pigs successfully underwent total pancreatectomy without requiring biliary reconstruction and were analyzed in the present study. Activity index was decreased from day 5 on and the mean survival of totally pancreatectomized pigs was 7.6 +/- 2.7 days. No endogenous insulin secretion was confirmed in these pigs. Pigs which received total pancreatectomy demonstrated significantly higher levels of ketone bodies. IVGTT performed within 4 days after total pancreatectomy showed a spontaneous decrease in blood glucose levels despite an absence of endogenous insulin secretion. IVGTT on day 5 or later showed continued hyperglycemia in pigs with total pancreatectomy. Histological examination showed atrophy of hepatocytes and decreased glycogen storage in the liver and decreased mucus production of the small intestine. CONCLUSION: This article describes a porcine model of diabetes created by total pancreatectomy and it analyzes the pathophysiological profiles in the animals. The present study has suggested that IVGTT on day 5 or later after total pancreatectomy is a reliable method to evaluate the efficacy of cell therapies.

Fatal hydrogen sulfide poisoning at a dye works.

An adult Japanese man (A) entered a pit to remove sludge in a drainage pipe at a dye works in Japan. When he took off a joint of the pipe, the sludge in the pipe flowed into the pit. As he suddenly lost consciousness, three colleagues (B, C, D) entered the pit to rescue him. All of these (A, B, C and D) lost consciousness in the pit, and died soon after the accident. Since hydrogen sulfide gas was detected in the sludge of the pit, gas poisoning was suspected. Toxicological analyses of sulfide and thiosulfate, a metabolite of sulfide, in blood and urine of the victims were made, using the extractive alkylation technique combined with gas chromatography/mass spectrometry. Sulfide and thiosulfate were detected in whole blood of the four workers at levels of 0.32-9.36 mg/l and 0.11-0.23 mmol/l, respectively. These concentrations were at least 6-187 times higher in sulfide and 37-77 times higher in thiosulfate than those in healthy persons, and were similar to values found in fatal cases of hydrogen sulfide poisoning. Thiosulfate was not detected in the urine of four workers, which indicated acute death. Based on these results, all four patients were victims of hydrogen sulfide poisoning, who died soon after the exposure.

Maintenance of glucose-sensitive insulin secretion of cryopreserved human islets with University of Wisconsin solution and ascorbic acid-2 glucoside.

Normal human islet cells are an ideal source for pancreas-targeted cell therapies, but the availability of human donor pancreata for islet isolation is severely limited. To effectively utilize such scarce donor organs for cell therapies, it is crucial to develop an excellent isolation, effective cryopreservation, and efficient gene transfer techniques for the transportation of isolated cells. In the present study, we investigate the effect of University of Wisconsin (UW) solution and ascorbic acid-2 glucoside (AA2G) on the cryopreservation of human islets. We also evaluate the gene transfer efficiency of a lentiviral vector expressing the E. coli LacZ gene, Lt-NLS/LacZ, in human islets. Human islets were isolated with a standard digestion method at the University of Alberta. Isolated islets were transported to Japan for 40 h and then subjected to cryopreservation experiments. The following preservation solutions were tested: UW solution with 100 micro g/mL of AA2G, UW solution, 100% fetal bovine serum (FBS), and CMRL supplemented with 10% FBS. Following three months of cryopreservation, the islets were thawed and analyzed for viability, glucose-sensitive insulin secretion, proinsulin gene expression profile, and in vivo engraftment. The islets were also subjected to monolayer formation with 804G-cell-line-derived extracellular matrix (ECM), followed by Lt-NLS/LacZ transduction. The viability, morphology, glucose-sensitive insulin secretion, proinsulin gene expression, and monolayer formation efficiency of the thawed cryopreserved islets are significantly better maintained by the use of UW solution. When AA2G (100 microg/mL) is combined with UW, such parameters are further improved. The adequate engraftment of UW + AA2G-cryopreserved human islets is achieved in the liver of nude mice. Efficient Lt-NLS/LacZ transduction is identified in monolayered islets cryopreserved with UW solution with AA2G. The present work demonstrates that the combination of UW solution with AA2G (100 microg/mL) would be a useful cryopreservation means for human islets. Human islets monolayer-cultured with 804G-derived ECM are efficiently transduced with a lentiviral vector Lt-NLS/LacZ.

Simultaneous determination of formate and acetate in whole blood and urine from humans using gas chromatography-mass spectrometry.

We devised a sensitive and simple method for simultaneous determination of formate and acetate in whole blood and urine from humans using gas chromatography-mass spectrometry. Formate and acetate were alkylated with pentafluorobenzyl bromide in the mixture of acetone and phosphate buffer (pH 6.8). The derivatives obtained were analyzed using gas chromatography-mass spectrometry in positive-ion electron ionization (EI) mode. The lower limit of detection for both compounds was 0.02mM. The calibration curves for formate and acetate were linear over the concentration range from 0.05 to 5.0mM. Accuracy and precision of the method were evaluated and the coefficients of variation were within 10%. With use of this method, levels of formate and acetate in whole blood can be determined in forensic cases.

Lentivirus-based gene delivery in mouse embryonic stem cells.

BACKGROUND: Embryonic stem (ES) cells are widely used in therapeutic research as an unlimited source of cell therapy. Therefore, it is of great value to find a way to efficiently manipulate ES cells. HIV-1-derived lentiviral vectors are now considered to be an efficient vehicle for delivering genes into a variety of cells. In this study, we examined the efficacy of lentivirus-based gene delivery into mouse ES (mES) cells. MATERIALS AND METHODS: Recombinant HIV-I-based lentiviral vectors Lt-GFP, expressing green fluorescent protein (GFP), and Lt-LacZ, expressing E. coli LacZ gene in conjunction with neomycin resistance gene, were generated using a FuGENE 6 transduction method and used for transducing ES cells derived from 129Sv mice. Lentiviral transduction efficacy was evaluated by GFP expression assay using flow cytometry and by X-gal staining. The in vivo potential of developing teratoma of such transduced mES cells was examined in severe combined immunodeficiency (SCID) mice. RESULTS: FuGENE 6 showed no considerable transduction-associated cytotoxicity. The expression rate of GFP and LacZ of mES cells increased on a multiplicity of infection (MOI)-dependent manner with the amount of Lt-GFP and Lt-LacZ used. Approximately 42% of mES cells were positive for GFP after infection of Lt-GFP at an MOI of 30. Notably, after G418 selection, nearly 100% of Lt-LacZ-transduced mES cells were positive for LacZ and formed teratomas in SCID mice. CONCLUSIONS: This work demonstrates that HIV-I-based lentiviral vectors are capable of transducing mES cells. Lentiviral vectors may facilitate an advance in the field of gene transfer and expression in various types of ES cells, including human ES cells.