Iron-sulfur clusters containing a singly or doubly NH.S hydrogen-bonded arenethiolate ligand, [Fe(4)S(4)(S-2-RCONHC(6)H(4))(4)](2)(-) (R = CH(3), t-Bu, CF(3)), [Fe(4)S(4){S-2,6-(RCONH)(2)C(6)H(3)}(4)](2)(-), [Fe(2)S(2)(S-2-RCONHC(6)H(4))(4)](2)(-) (R = CH(3), t-Bu, CF(3)), and [Fe(2)S(2){S-2,6-(RCONH)(2)C(6)H(3)}(4)](2)(-), were synthesized as models of bacterial [4Fe-4S] and plant-type [2Fe-2S] ferredoxins. The X-ray structures and IR spectra of (PPh(4))(2)[Fe(4)S(4){S-2,6-(CH(3)CONH)(2)C(6)H(3)}(4)].2CH(3)CN and (NEt(4))(2)[Fe(2)S(2){S-2,6-(t-BuCONH)(2)C(6)H(3)}(4)] indicate that the two amide NH groups at the o,o'-positions are directed to the thiolate sulfur atom and form double NH.S hydrogen bonds. The NH.S hydrogen bond contributes to the positive shift of the redox potential of not only (Fe(4)S(4))(+)/(Fe(4)S(4))(2+) but also (Fe(4)S(4))(2+)/(Fe(4)S(4))(3+) in the [4Fe-4S] clusters as well as (Fe(2)S(2))(2+)/(Fe(2)S(2))(3+) in the [2Fe-2S] clusters. The doubly NH.S hydrogen-bonded thiolate ligand effectively prevents the ligand exchange reaction by benzenethiol because the two amide NH groups stabilize the thiolate by protection from dissociation.

We examined the oxidative burst (hydrogen peroxide-dependent oxidative product formation) of polymorphonuclear leukocytes (PMNL) in the peripheral blood from the patients with various types of periodontal diseases including localized juvenile (LJP), generalized juvenile (GJP) and adult periodontitis (AP). Heparinized peripheral blood was obtained from 15 LJP, 13 GJP and 52 AP patients and from 30 healthy control subjects. The oxidative product (2',7'-dichlorofluorescein; DCF) formation of PMNL by stimulation with phorbol myristate acetate myristate acetate was evaluated by a rapid quantitative assay using flow cytometry. The results indicated that all patient groups contained variable populations with normal or increased DCF formation, while the control subjects exhibited DCF formation as a single population. No significant differences in average DCF formation were found among the three patient groups. Although individual patients gave various values, the average DCF formation of the three patient groups was much higher than that of the control group. Statistical analysis revealed a significant positive correlation between DCF formation and the clinical periodontal parameters on an individual basis. Furthermore, after initial periodontal treatment, DCF formation decreased to normal levels. These results suggest that the capacity of peripheral blood PMNL to mount oxidative burst reactions might reflect the inflammatory status of periodontal disease.

The backside-ligand modulation strategy to enhance the substrate binding property of Pd clusters is reported. The benzene or naphthalene binding ability of Pd3 or Pd4 clusters is enhanced significantly by the backside cyclooctatetraene ligand, leading to the formation of the first solution-stable benzene- or naphthalene Pd clusters. The present results imply that the ligand design of the metal clusters, especially for the backside ligand of the metal cluster site, is crucial to acquire a desired reactivity of metal clusters.

Sepsis is a systemic inflammatory response to infection, accounting for the most common cause of death in intensive care units. Here, we report that peripheral administration of the hypothalamic neuropeptide orexin improves the survival of mice with lipopolysaccharide (LPS) induced endotoxin shock, a well-studied septic shock model. The effect is accompanied by a suppression of excessive cytokine production and an increase of catecholamines and corticosterone. We found that peripherally administered orexin penetrates the blood-brain barrier under endotoxin shock, and that central administration of orexin also suppresses the cytokine production and improves the survival, indicating orexin’s direct action in the central nervous system (CNS). Orexin helps restore body temperature and potentiates cardiovascular function in LPS-injected mice. Pleiotropic modulation of inflammatory response by orexin through the CNS may constitute a novel therapeutic approach for septic shock.DOI: http://dx.doi.org/10.7554/eLife.21055.001

π-Coordination of pyrrole or indole which lack a chelating functionality to a dinuclear Pd(I)-Pd(I) center is revealed. The dinuclear sandwich Pd(I)-Pd(I) complexes of pyrrole, N-methylpyrrole, or indole were synthesized and structurally characterized by X-ray crystallographic analysis. Indole employs the carbons of the six-membered ring in bridging π-coordination to a Pd(I)-Pd(I) center.

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Sandwich time! The mixed-metal triangular-trinuclear sandwich complexes of Pd(2)Pt and PdPt(2) were selectively synthesized. The Pd(2)Pt and PdPt(2) triangles in a cycloheptatrienyl sandwich framework were identified by (31)P NMR analyses of the tris-triphenylphosphine complexes (see scheme).