Genetic relationships within the Opisthorchis viverrini species complex with specific analysis of O. viverrini from Savannakhet, Lao PDR by multilocus enzyme electrophoresis

Recent systematic studies of Opisthorchis viverrini based on multilocus enzyme electrophoresis (MEE) have shown that there are at least five genetic groups and possibly two cryptic species occurring in Thailand and Lao PDR each associated with a specific wetland system. A study based on mitochondrial DNA (mtDNA) gene analyses of an O. viverrini population from Savannakhet (SV, Lao PDR) clustered with several isolates from Thailand and Lao PDR although they originated from different river wetland systems. We used MEE to re-examine whether O. viverrini from SV was similar genetically to isolates from Thailand and Lao PDR. The allelic profiles of O. viverrini from SV and five different wetlands representing defined genetic groups of O. viverrini were recorded at 24 enzyme loci as opposed to only two loci of mtDNA. Contrary to previous studies, O. viverrini from SV was found to have fixed genetic differences at six to eight of the 24 loci examined (24.50–35.42%). Allelic data indicated that O. viverrini from SV differed from isolates in the Nam Ngum River wetland in Lao PDR (29.33% fixed genetic differences) and clustered with O. viverrini from Nakhon Phanom and Sakon Nakhon within the Songkram River wetland in Thailand but had fixed genetic differences from these at 24.5% of loci examined. Our data confirm the association between genetic groups of O. viverrini and specific wetland systems, and raise important questions regarding the significance of the genetic differences and relationships of O. viverrini from these wetlands.     

In vitro antioxidant activity study of novel chromone derivatives

Forty-eight chromone derivatives were evaluated for their antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl free radical scavenging assay, ferrous ions (Fe(2+) ) chelating activity test, total antioxidant activity test (Ferric thiocyanate and Thiobarbituric acid methods), and total reductive capability (potassium ferricyanide reduction). 7,8-Dihydroxy-2-(3'-trifluoromethylphenyl)-3-(3″-trifluoromethylbenzoyl) chromone 32 showed stronger radical scavenging and metal chelating activities than butylated hydroxytoluene, vitamin E, and trolox. Chromone derivatives that exhibited good radical scavenging and metal chelating also displayed strong total antioxidant and reductive power activities. The results obtained from this study indicated that the synthesized chromone derivatives have remarkable antioxidant activity.     

AMPK controls epithelial Na+ channels through Nedd4-2 and causes an epithelial phenotype when mutated

The metabolic sensor adenosine-monophosphate-activated kinase (AMPK) detects the cellular energy status and adjusts metabolic activity according to the cytosolic AMP to ATP ratio. Na⁺ absorption by epithelial Na⁺ channels (ENaC) is a highly energy-consuming process that is inhibited by AMPK. We show that the catalytic subunit α1 of AMPK inhibits ENaC in epithelial tissues from airways, kidney, and colon and that AMPK regulation of ENaC is absent in AMPKα1−/− mice. These mice demonstrate enhanced electrogenic Na⁺ absorption that leads to subtle changes in intestinal and renal function and may also affect Na⁺ absorption and mucociliary clearance in the airways. We demonstrate that AMPK uses the ubiquitin ligase Nedd4-2 to inhibit ENaC by increasing ubiquitination and endocytosis of ENaC. Thus, enhanced expression of epithelial Na⁺ channels was detected in colon, airways, and kidney of AMPKα1−/− mice. Therefore, AMPKα1 is a physiologically important regulator of electrogenic Na⁺ absorption and may provide a novel pharmacological target for controlling epithelial Na⁺ transport. Categories: Membranes and Transport; bioenergetics, anabolic/catabolic processes studied at the molecular level.     

Regulation of Cl− secretion by AMPK in vivo

Previous in vitro studies suggested that Cl(-) currents produced by the cystic fibrosis transmembrane conductance regulator (CFTR; ABCC7) are inhibited by the alpha1 isoform of the adenosine monophosphate (AMP)-stimulated kinase (AMPK). AMPK is a serine/threonine kinase that is activated during metabolic stress. It has been proposed as a potential mediator for transport-metabolism coupling in epithelial tissues. All previous studies have been performed in vitro and thus little is known about the regulation of Cl(-) secretion by AMPK in vivo. Using AMPKalpha1(-/-) mice and wild-type littermates, we demonstrate that phenformin, an activator of AMPK, strongly inhibits cAMP-activated Cl(-) secretion in mouse airways and colon, when examined in ex vivo in Ussing chamber recordings. However, phenformin was equally effective in AMPKalpha1(-/-) and wild-type animals, suggesting additional AMPK-independent action of phenformin. Phenformin inhibited CFTR Cl(-) conductance in basolaterally permeabilized colonic epithelium from AMPKalpha1(+/+) but not AMPKalpha1(-/-) mice. The inhibitor of AMPK compound C enhanced CFTR-mediated Cl(-) secretion in epithelial tissues of AMPKalpha1(-/-) mice, but not in wild-type littermates. There was no effect on Ca(2+)-mediated Cl(-) secretion, activated by adenosine triphosphate or carbachol. Moreover CFTR-dependent Cl(-) secretion was enhanced in the colon of AMPKalpha1(-/-) mice, as indicated in Ussing chamber ex vivo and rectal PD measurements in vivo. Taken together, these data suggest that epithelial Cl(-) secretion mediated by CFTR is controlled by AMPK in vivo.     

An extract from the medicinal plant Phyllanthus acidus and its isolated compounds induce airway chloride secretion: A potential treatment for cystic fibrosis

According to previous reports, flavonoids and nutraceuticals correct defective electrolyte transport in cystic fibrosis (CF) airways. Traditional medicinal plants from China and Thailand contain phytoflavonoids and other bioactive compounds. We examined herbal extracts of the common Thai medicinal euphorbiaceous plant Phyllanthus acidus for their potential effects on epithelial transport. Functional assays by Ussing chamber, patch-clamping, double-electrode voltage-clamp and Ca2+ imaging demonstrate activation of Cl- secretion and inhibition of Na+ absorption by P. acidus. No cytotoxic effects of P. acidus could be detected. Mucosal application of P. acidus to native mouse trachea suggested transient and steady-state activation of Cl- secretion by increasing both intracellular Ca2+ and cAMP. These effects were mimicked by a mix of the isolated components adenosine, kaempferol, and hypogallic acid. Additional experiments in human airway cells and CF transmembrane conductance regulator (CFTR)-expressing BHK cells and Xenopus laevis oocytes confirm the results obtained in native tissues. Cl- secretion was also induced in tracheas of CF mice homozygous for Phe508del-CFTR and in Phe508del-CFTR homozygous human airway epithelial cells. Taken together, P. acidus corrects defective electrolyte transport in CF airways by parallel mechanisms including 1) increasing the intracellular levels of second messengers cAMP and Ca2+, thereby activating Ca2+-dependent Cl- channels and residual CFTR-Cl- conductance; 2) stimulating basolateral K+ channels; 3) redistributing cellular localization of CFTR; 4) directly activating CFTR; and 5) inhibiting ENaC through activation of CFTR. These combinatorial effects on epithelial transport may provide a novel complementary nutraceutical treatment for the CF lung disease.     

Extraskeletal giant cell tumor of the larynx: case report and review of the literature

Giant cell tumors of the larynx typically arise within the laryngeal skeleton. We report a case of a laryngeal tumor in a 29-year-old man that clearly originated outside the laryngeal cartilage. It was identified as a soft-tissue giant cell tumor. To the best of our knowledge, an extraskeletal laryngeal giant cell tumor has not been previously reported.     

An antimalarial tetrapeptide from the entomopathogenic fungus Hirsutella sp. BCC 1528

Hirsutellic acid A (1), a new linear tetrapeptide possessing an anthranilic acid residue at the C-terminus, was isolated from a fermentation broth of the entomopathogenic fungus Hirsutella sp. BCC 1528. The structure of this compound was elucidated by NMR and MS analyses, and its absolute configuration was deduced by HPLC analysis of the acid hydrolysate using a chiral column. Hirsutellic acid A exhibits activity against the malarial parasite Plasmodium falciparum K1 with an IC(50) value of 8.0 microM, while it was noncytotoxic to Vero cells at a concentration of 95 microM.     

Pulmonary tuberculosis in a child presenting with acute hemoptysis

We report on a tuberculous child whose only presenting symptom was acute hemoptysis. His chest radiograph revealed a mass-like lesion occupying the posterior basal segment of the right lower lung field. Multidetector computerized tomography (MDCT) of the chest showed a hypodense mass supplied by the bronchial artery and drained by the pulmonary vein. Surgical specimens revealed caseating granulomatous inflammation, positive for acid-fast bacilli. The child was successfully treated with a short-course (6-month) regimen of antituberculous drugs.