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The polyamines spermidine and spermine, and their precursor putrescine, are required for cell growth and cellular functions. The high levels of tissue polyamines are implicated in carcinogenesis. The major sources of exogenous polyamines are diet and intestinal luminal bacteria in gastrointestinal (GI) tissues. Both endocytic and solute carrier-dependent mechanisms have been described for polyamine uptake. Knocking down of caveolin-1 protein increased polyamine uptake in colon cancer-derived HCT116 cells. Dietary supplied putrescine was accumulated in GI tissues and liver in caveolin-1 knockout mice more than wild-type mice. Knocking out of nitric oxide synthase (NOS2), which has been implicated in the release of exogenous polyamines from internalized vesicles, abolished the accumulation of dietary putrescine in GI tissues. Under conditions of reduced endogenous tissue putrescine contents, caused by treatment with the polyamine synthesis inhibitor difluoromethylornithine (DFMO), small intestinal and colonic mucosal polyamine contents increased with dietary putrescine levels, even in mice lacking NOS2. Knocking down the solute carrier transporter SLC3A2 in HCTll6-derived Hlda2 cells reduced the accumulation of exogenous putrescine and total polyamine contents in DFMO treated cells, relative to non-DFMO-treated cells. These data demonstrate that exogenous putrescine is transported into GI tissues by caveolin-1- and NOS2-dependent mechanisms, but that the solute carrier transporter SLC3A2 can function bidirectionally to import putrescine under conditions of low tissue polyamines. caveolin-1; NOS2; SLC3A2; gastrointestinal tissue doi: 10.1152/ajpgi.00169.2010.

A spermidine excretion protein in Escherichia coli was looked for among 33 putative drug exporters thus far identified. Cell toxicity and inhibition of growth due to overaccumulation of spermidine were examined in an E. coli strain deficient in spermidine acetyltransferase, an enzyme that metabolizes spermidine. Toxicity and inhibition of cell growth by spermidine were recovered in cells transformed with pUCmdtJI or pMWmdtJI, encoding MdtJ and MdtI, which belong to the small multidrug resistance family of drug exporters. Both mdtJ and mdtI are necessary for recovery from the toxicity of overaccumulated spermidine. It was also found that the level ofmdtJI mRNA was increased by spermidine. The spermidine content in cells cultured in the presence of 2 mM spermidine was decreased, and excretion of spermidine from cells was enhanced by MdtJI, indicating that the MdtJI complex can catalyze excretion of spermidine from cells. It was found that [Tyr.sup.4], [Trp.sup.5], [Glu.sup.15], [Tyr.sup.45], [Tyr.sup.61], and [Glu.sup.82] in MdtJ and [Glu.sup.5], [Glu.sup.19], [Asp.sup.68], [Trp.sup.68], and [Trp.sup.81] in MdtI are involved in the excretion activity of MdtJI.

A demonstration showing that aryl- or vinylboronic acids add to the N=N double bond in diazodicarboxylates under mild reaction conditions with a high efficiency with emphasis on scope and limitations is presented. The reaction is a useful method for the preparation of aryl-substituted hydrazines and tolerates a wide variety of functional groups.

The reaction of 2-arylpyridines with ethylene and carbon monoxide in the presence of a catalytic amount of [Rh.sub.4][(CO).sub.12] results in selective carbonylation at the ortho C--H bond. The reaction is heavily dependent on the solvents used, with DMA (N,N-dimethylacetamide) being the solvent of choice. Steric factors are also important determinants of the efficiency of the reaction. Key words: C--H bond activation, carbonylation, chelation, rhodium, carbon monoxide. La reaction des 2-arylpyridines avec l'ethylene et le monoxyde de carbone, en presence d'une quantite catalytique de [Rh.sub.4][(CO).sub.12] conduit a une carbonylation selection au niveau de la liaison C--H en ortho. La reaction depend fortement de la nature du solvant utilise et le DMA (N,N-dimethyacetamide) est le solvant de choix. Les facteurs steriques sont aussi determinants dans l'efficacite de la reaction. Mots cles : activation d'une liaison C--H, carbonylation, chelation, rhodium, monoxyde de carbone. [Traduit par la Redaction]

Background: VitalTalk is an established training program for serious illness conversations in the US. Previously, this training course has been provided in-person in Japanese, but never virtually. Objectives: To evaluate the feasibility of a virtually administered VitalTalk workshop in Japanese. Setting/Subjects: We conducted a virtual workshop which consisted of 2 days (3 hours per day) of synchronous sessions and preceding asynchronous modules. Five VitalTalk faculty members in the US facilitated 4 workshops for 48 physicians from 33 institutions across Japan. Learners completed surveys before and after the workshop. Measurements: To evaluate the feasibility, learners were asked for their satisfaction with the workshop and the virtual format as primary outcomes and their self-assessed preparedness in serious illness communication as the secondary outcome. Each question employed a 5-point Likert scale. Results: All learners (n = 48, male 79%) participated in the survey. The mean score of the learners' satisfaction was 4.69 or higher in all questions. The mean score of the virtual format's satisfaction was 4.33 or higher in all questions. The mean score of self-reported preparedness on the 11 questions were between 2.30 and 3.34 before the workshop, all of which significantly increased to 3.08 through 3.96 after the workshop (p < 0.01 in all questions). Conclusion: Learners in Japan perceived the virtual format of our VitalTalk workshop as satisfactory, and their self-reported preparedness improved significantly after the workshop. VitalTalk faculty members in the US were able to provide virtual communication training to physicians in Japan. [ABSTRACT FROM AUTHOR]