Fulminant hepatic failure attributed to infection with human herpesvirus 6 (HHV-6) in an immunocompetent woman: A case report and review of the literature.

Mild disease due to human herpesvirus-6 (HHV-6) has been reported in healthy children. Severe disease due to this virus can occur in immunocompromised patients but is rarely reported in previously healthy adults. We report the case of a previously healthy woman who presented with a skin rash, mild upper respiratory symptoms, and abdominal pain and succumbed to fulminant hepatic failure attributed to infection with HHV-6B. HHV-6 may be more commonly associated with fulminant hepatitis in immunocompetent patients than previously thought and should be considered in the differential diagnosis of patients presenting with skin rash, upper respiratory symptoms, and unexplained hepatitis.

A fatal case of acute HHV-6 myocarditis following allogeneic haemopoietic stem cell transplantation.

Human herpesvirus 6 (HHV-6) is an ubiquitous virus that can reactivate in immunocompromised hosts, resulting in diverse clinical sequelae. We describe a case of fatal acute HHV-6 myocarditis in a patient who underwent allogeneic haemopoietic stem cell transplantation (HSCT). To our knowledge, this is the first reported case of biopsy proven HHV-6 myocarditis post-HSCT.

Stretch reduces central core lesions and calcium build-up in tenotomized soleus.

The incidence of skeletal muscle tendon rupture is increasing. The unloaded, shortened muscle undergoes rapid degeneration. Rehabilitation takes 10-12 weeks and includes stretch therapy. Outcomes may be improved by understanding the pathophysiological changes and stretch mechanisms. We investigated the effects of passive stretch on preventing central core lesions in a rat tenotomy model of simulated Achilles tendon rupture. Adult male rats were tenotomized bilaterally. At 7 days, 39% of the soleus fibers possessed central core lesions. Whole muscle calcium concentration progressively increased and plateaued by 4 days. Dantrolene, a calcium release blocker, injected daily for 7 days, reduced central core lesion formation and calcium build-up. Passive stretch, 20 min/day, inhibited central core lesion formation. Calcium increased at 4 days in mitochondria, and stretch prevented this increase. These findings indicate that stretch therapy reduces central core lesion occurrence by preventing calcium elevation in hypershortened muscles.

Endothelium-derived 2-arachidonylglycerol: an intermediate in vasodilatory eicosanoid release in bovine coronary arteries.

Acetylcholine stimulates the release of endothelium-derived arachidonic acid (AA) metabolites including prostacyclin and epoxyeicosatrienoic acids (EETs), which relax coronary arteries. However, mechanisms of endothelial cell (EC) AA activation remain undefined. We propose that 2-arachidonylglycerol (2-AG) plays an important role in this pathway. An AA metabolite isolated from bovine coronary ECs was identified as 2-AG by mass spectrometry. In ECs pretreated with the fatty acid amidohydrolase inhibitor diazomethylarachidonyl ketone (DAK; 20 micromol/l), methacholine (10 micromol/l)-stimulated 2-AG release was blocked by the phospholipase C inhibitor U-73122 (10 micromol/l) or the diacylglycerol lipase inhibitor RHC-80267 (40 micromol/l). In U-46619-preconstricted bovine coronary arterial rings, 2-AG relaxations averaging 100% at 10 micromol/l were inhibited by endothelium removal, by DAK, by the hydrolase inhibitor methyl arachidonylfluorophosphate (10 micromol/l), by the cyclooxygenase inhibitor indomethacin (10 micromol/l), but not by the CB1 cannabinoid receptor antagonist SR-141716 (1 micromol/l). The cytochrome P-450 inhibitor SKF-525a (10 micromol/l) and the 14,15-epoxyeicosa-5Z-enoic acid EET antagonist (14,15-EEZE; 10 micromol/l) further attenuated the indomethacin-resistant relaxations. The nonhydrolyzable 2-AG analogs noladin ether, 2-AG amide, and 14,15-EET glycerol amide did not induce relaxation. N-nitro-L-arginine-resistant relaxations to methacholine were also inhibited by U-73122, RHC-80267, and DAK. 14,15-EET glycerol ester increased opening of large-conductance K(+) channels 12-fold in cell-attached patches of isolated smooth muscle cells and induced relaxations averaging 95%. These results suggest that methacholine stimulates EC 2-AG production through phospholipase C and diacylglycerol lipase activation. 2-AG is further hydrolyzed to AA, which is metabolized to vasoactive eicosanoids. These studies reveal a role for 2-AG in EC AA release and the regulation of coronary tone.