Hydroxyhydroquinone, a by-product of coffee bean roasting, increases intracellular Ca2+ concentration in rat thymic lymphocytes.

Hydroxyhydroquinone (HHQ) is generated during coffee bean roasting. A cup of coffee contains 0.1-1.7 mg of HHQ. The actions of HHQ on mammalian DNA were examined because HHQ is a metabolite of benzene, which causes leukemia. Currently, information on the cellular actions of HHQ is limited. We examined the effects of sublethal levels of HHQ on the concentration of intracellular Ca2+ in rat thymic lymphocytes by using a flow cytometric technique with fluorescent probes. HHQ at 10 µM or more significantly elevated intracellular Ca2+ levels by increasing the membrane permeability of divalent cations, resulting in hyperpolarization via the activation of Ca2+-dependent K+ channels. HHQ-induced changes in the intracellular Ca2+ concentration and membrane potential may affect the cell functions of lymphocytes. HHQ-reduced coffee may be preferable in order to avoid the possible adverse effects of HHQ.

An oxidative coupling product of luteolin with cysteine ester and its enhanced inhibitory activity for xanthine oxidase.

Oxidative coupling reactions of several flavonoids with a cysteine ester (a radicalic and nucleophilic biochemical) were carried out and the abilities of the coupling products against xanthine oxidase (XO) were screened. One of the products, derived from luteolin, showed a notable inhibitory effect. A potent XO inhibitory compound was isolated from the complex mixture of the product of the coupling of luteolin and cysteine ethyl ester, and its structure was determined by NMR and MS analysis. The compound has a unique 1,4-thiazine ring unit on the luteolin B-ring and is inhibited XO 4.5 times more strongly than it did luteolin.

Variations of the ulnar nerve in Guyon's canal: in vivo demonstration using ultrasound and 3 T MRI.

BACKGROUND: The clinical importance of Guyon's canal is emphasized due to the various branching patterns of the ulnar nerve. So far, the arborization pattern of the ulnar nerve in Guyon's canal has been investigated mostly by cadaveric studies. PURPOSE: To demonstrate anatomic variations of the ulnar nerve in Guyon's canal in vivo by using high definition ultrasound (US) and 3 T magnetic resonance imaging (MRI). MATERIAL AND METHODS: US imaging and 3 T MRI with an 8-channel coil was applied to 30 hands of 15 volunteers. The main trunk and the branched superficial and deep ulnar nerves, including neural bifurcation or trifurcation, were recognized on US and confirmed by 3 T MR images. The ulnar artery and vein and its branches were traced on color Doppler US and also visualized by MRI. The branching pattern of the ulnar nerve was determined from the inlet to the outlet of Guyon's canal. RESULTS: Of 30 hands, 21 (70%) revealed bifurcation and 9 (30%) had trifurcation branching pattern of the ulnar nerve. In 16 hands (54%), imaging demonstrated that a single nerve entered the canal and divided into two trunks, one superficial and one deep, then exited the canal. The bifurcation occurred predominantly just after entering the canal inlet. The typical trifurcation pattern indicated that a single trunk entered the canal and divided into two, then one of the two bifurcated, producing a trifurcated pattern with two superficial and one deep bundle. Of 15 participants, symmetrical branching of bilateral hands was identified in 4 cases (27%), whereas 11 (73%) had asymmetrical branching. CONCLUSION: US and 3 T MRI readily delineated the branching pattern of the ulnar nerve in Guyon's canal in vivo. Morphological understanding about this neural branching can be informative in presurgical planning and also in diagnosis.