Exceptional crystallization diversity and solid-state conversions of Cd(II) coordination frameworks with 5-bromonicotinate directed by solvent media.

A series of nine coordination polymers {[Cd(L)(2)(solvent)(x)](solvent)(y)}(n) have been prepared from Cd(NO(3))(2) and 5-bromonicotinic acid (HL) in different solvents through a layered diffusion method. By using CH(3)OH/H(2)O at different volume ratios of 1:1 and 1:3, a one-dimensional (1D) coordination species (1a) and a three-dimensional (3D) (3,6)-connected framework (2a·g(1)) can be obtained. A similar self-assembly process in C(2)H(5)OH/H(2)O or H(2)O/1,4-dioxane gives 2a·g(2) or 2a·g(3), which are isomorphic to 2a·g(1) but with different lattice solvents. Replacement of the mixed solvents with DMF/H(2)O (v/v 1:1 or 1:3) also gives a 1D chain complex (1b) or a 3D microporous framework (2b·g(1)). Similarly, MOF 2b·g(2) can be assembled from CH(3)CN/H(2)O as an isomorphic solvate of 2b·g(1). Significantly, the 3D MOF families of 2a·g(n) and 2b·g(n) are supramolecular isomers even though they are topologically equivalent. Also, if a mixture of CH(3)OH/CH(2)Cl(2) (v/v 1:1 or 3:1) is used, a pair of distinct MOFs (3a·g) and (3b) are generated as pseudo-polymorphs that show a two-dimensional (2D) sheet and a 3D coordination framework, respectively. Furthermore, mutual solvent-induced conversions were realized between 1a and 1b and between 2a·g(1), 2a·g(2), and 2a·g(3) following the size-dependent rule of the solvent. These results are of great significance in recognizing the solvent effect upon coordination assemblies and their crystal transformations.

[NDM-1-producing Klebsiella pneumoniae in mainland China].

OBJECTIVE: To investigate the characteristics of New Delhi metallo-beta-lactamase-1 (NDM-1) gene of Klebsiella pneumoniae (K. pneumoniae) emerging in Hunan, and its relationship to antibiotic resistance. METHODS: The clinical strain was isolated from a sputum sample of a child with severe pnemonia and toxic myocarditis who was admitted into a general hospital of Hunan Province. VITEK-2 compact instrument was used for bacterial identification and antibiotic susceptibility test. Modified Hodge test was used for the screening of carbapenemase. EDTA-synergy test and combination disk diffusion test were used for detection of metallo-ß-lactamase (MBL). PCR was performed for amplification of NDM-1 genes and the positive products were sequenced and analyzed with BLAST. Conjugation was also performed to analyze mechanisms of antibiotic resistance. The results of antibiotic susceptibility tests were compared before and after conjugation. RESULTS: The isolated strain was identified as K.pneumoniae. Modified Hodge test, EDTA-synergy test and combination disk diffusion test were all positive for the strain. The homology between gene sequence of PCR amplification products and NDM-1 gene FN396876.1 in the GenBank was 100%. Transconjugant DNA was used as template for the amplification of NDM-1 gene. The amplification products were sequenced and found to be the same as the NDM-1 gene amplification product of the donor strain. The MIC of transconjugant E.coli J53 (NDM-1) to all the ß-lactams increased significantly compared with the recipient strain E.coli J53. The MIC of ertapenem and imipenem increased by more than 8 times, while the MIC of ceftazidime and ceftriaxone increased by more than 64 times. CONCLUSIONS: This study first identified a strain of K. pneumoniae carrying NDM-1 in mainland China. NDM-1 gene can be transmitted among different strains and causes extensively drug-resistance to ß-lactams.

Inducing effect of additive agents on coordination assembly of silver(I) nitrate with 3,5-bis(2-pyridyl)-4-amino-1,2,4-triazole: supramolecular isomerism and interconversion.

By using different organic acids as additive agents, hydrothermal reactions of AgNO(3) with 3,5-bis(2-pyridyl)-4-amino-1,2,4-triazole (2-bpt) lead to formation of two conformational polymorphs of [Ag(2-bpt)](NO(3)) with bimetallocyclic and 1-D helical coordination patterns. Interconversion between the two supramolecular isomers can be achieved under proper conditions, which will pass through the same intermediate state.

3,4-Bis(2-pyrid-yl)-5-(3-pyrid-yl)-4H-1,2,4-triazole.

In the title mol-ecule, C(17)H(12)N(6), the 2-pyridyl rings in the 3- and 4-positions and the 3-pyridyl ring in the 5-position make dihedral angles of 29.78 (16), 67.06 (16) and 32.97 (16)°, respectively, with the triazole group. The dihedral angle between the two 2-pyridyl rings is 65.72 (15)°. The dihedral angles between the 3-pyridyl ring and the two 2-pyridyl rings in the 3- and 4-positions are 61.28 (15) and 63.11 (15)°, respectively. In the crystal, C-H⋯π and π-π inter-actions [centroid-centroid distance = 3.6248 (19) Å] link the mol-ecules, forming a two-dimensional network.

2,5-Bis(5-methyl-pyrazin-2-yl)-1,3,4-oxadiazole.

In the title mol-ecule, C(12)H(10)N(6)O, the dihedral angle between the two pyrazine rings [planar to within 0.009 (3) and 0.018 (3) Å] is 5.62 (15)°. They deviate from the central oxadiazole ring [planar to within 0.005 (3) Å] by 1.52 (16) and 5.55 (17)°, respectively. In the crystal, C-H⋯N inter-actions involving the pyrazine rings connect mol-ecules to form zigzag supramolecular chains propagating in [010].

Therapeutic efficacy of milrinone in the management of enterovirus 71-induced pulmonary edema.

Hand, foot, and mouth disease and herpangina are the major clinical manifestations of enterovirus 71 (EV71) infections. Brain-stem encephalitis and pulmonary edema are severe complications that can lead to death. This study was designed to evaluate the potential therapeutic effect of milrinone, a phosphodiesterase (PDE) inhibitor, in the treatment of patients with EV71-induced pulmonary edema. We conducted a historically controlled trial of 24 children with severe EV71-induced pulmonary edema from April 1998-June 2003 in southern Taiwan. Patients were divided into groups treated before and after the introduction of milrinone therapy. Etiological diagnosis was established by viral cultures and confirmed by specific immunofluorescence and neutralization tests. All 24 patients were below 5 years of age. The mortality was lower in the milrinone-treated vs. nontreated group (36.4% vs. 92.3%, P=0.005). Sympathetic tachycardia was decreased in patients treated with milrinone compared to controls (144 +/- 17/min vs. 206 +/- 26/min, P=0.004). A marked decrease in IL-13 (77 +/- 9 pg/ml vs. 162 +/- 88 pg/ml, P=0.001) was observed in milrinone-treated patients compared to controls. There was a significant reduction in white blood cell (10,838 +/- 4,537/mm3 vs. 19,475 +/- 7,798/mm3, P=0.009) and platelet (257 +/- 45 x 10(3)/mm3 vs. 400 +/- 87 x 10(3)/mm3, P=0.001) counts in milrinone-treated patients compared to controls. These results were associated with improvement in sympathetic regulation and decrease in IL-13 production. Milrinone therapy may provide a useful therapeutic approach for this highly lethal disorder.

[Pharmacokinetic study of intraperitoneal chemotherapy with HCPT].

OBJECTIVE: To study the pharmacokinetic of 10-Hydroxycamptothecin HCPT by intraperitoneal administration. METHOD: Six dogs were given HCPT by intraperitoneal perfusion: HCPT 2 mg x kg(-1), dissolved in 300 mL NS. During the course of experiments, peritoneal fluids and blood were sampled using a standardized protocol. The concentration of HCPT in all samples was determined by high performance liquid chromatography (HPLC). RESULT: The area under the curve (AUC) of peritoneal fluids was significantly highly as compared to the AUC of femoral vein and portal vein (P < 0.001). CONCLUSION: These experiments demonstrate that intraperitoneal chemotherapy has significant effect on the pharmacokinetics of IP route of HCPT administration. This method should be a more reasonable chemotherapy for the prevention of recurrence and liver metastasis of gastric cancer, colon cancer and ovary cancer after radical resection.

Destruction and reconstruction of the robust [Cu2(OOCR)4] unit during crystal structure transformations between two coordination polymers.

This work first demonstrates that the robust [Cu(2)(OOCR)(4)] unit can be destroyed and reconstructed in the solid state, as observed in water-induced structural interconversion of two distinct coordination polymers with 5-bromonicotinate.