Reactivity investigation of dinuclear vanadium(IV,V)-citrate complexes in aqueous solutions. A closer look into aqueous vanadium-citrate interconversions

Well-known vanadium(IV)- and vanadium(V)-citrate complexes have been employed in transformations involving vanadium redox as well as nonredox processes. The employed complexes include K(2)[V(2)O(4)(C(6)H(6)O(7))(2)] x 4H(2)O, K(4)[V(2)O(4)(C(6)H(5)O(7))(2)] x 5.6H(2)O, K(2)[V(2)O(2)(O(2))(2)(C(6)H(6)O(7))(2)] x 2H(2)O, K(4)[V(2)O(2)(C(6)H(4)O(7))(2)] x 6H(2)O, K(3)[V(2)O(2)(C(6)H(4)O(7))(C(6)H(5)O(7))] x 7H(2)O, (NH(4))(4)[V(2)O(2)(C(6)H(4)O(7))(2)] x 2H(2)O, and (NH(4))(6)[V(2)O(4)(C(6)H(4)O(7))(2)] x 6H(2)O. Reactions toward hydrogen peroxide at different vanadium(IV,V):H(2)O(2) ratios were crucial in delineating the routes leading to the interconversion of the various species. Equally important thermal transformations were critical in showing the linkage between pairs of dinuclear vanadium-citrate peroxo as well as nonperoxo complexes, for which the important vanadium(V)-assisted oxidative decarboxylation, leading to reduction of vanadium(V) to vanadium(IV), seemed to be a plausible pathway in place for all the cases examined. FT-IR spectroscopy and X-ray crystallography were instrumental in the identification of the arising products of all investigated reactions. Collectively, the data support the existence of chemical links between different and various structural forms of dinuclear vanadium(IV,V)-citrate complexes in aqueous media. Furthermore, in corroboration of past studies, the examined interconversions lend credence to the notion that the involved species are active participants in the respective aqueous distributions of the metal ion in the presence of the physiological ligand citrate. The concomitant significance of structure-specific species relating to soluble and potentially bioavailable forms of vanadium is mentioned.

Ascites associated with the initial presentation of Crohn's disease

We report a case of a 23-yr-old patient who was initially admitted with severe Crohn's ileocolitis complicated by a large amount of exudative ascites. There was no evidence of malignancy, portal hypertension, or inflammation in any organ other than the bowel. We present the clinical course and response to treatment and discuss the possible mechanisms by which Crohn's disease might contribute to the development of exudative ascites.

Q fever in the Greek Island of Crete: epidemiologic, clinical, and therapeutic data from 98 cases

A retrospective study was undertaken in Crete, Greece, to investigate the epidemiologic, clinical, and therapeutic aspects of Q fever. Over a period of 5 years (1989-1993), 1,298 patients were examined and 98 cases were identified. Individuals who were aged 20-29 years and 30-39 years appeared to have an increased risk of infection. Contact with animals was found to be a major risk factor for acquisition of Q fever. The predominant clinical manifestations of the infection were fever (91.7% of patients) and respiratory disease (88.5%), whereas hepatitis was the dominant feature in only a minority (7.1%) of patients. Chest radiographs frequently revealed pulmonary interstitial changes (36.4% of patients) and alveolar changes (34.4%). Abnormal echocardiographic findings were also observed. There was no difference in the duration of fever whether the patient received therapy with tetracycline or erythromycin, a finding that may be explained by the delay in initiating tetracycline therapy.