M. T. Clunes

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The perforated patch recording technique was used to investigate the effects of dexamethasone (0.2 microm, 24-30 h), a synthetic glucocorticoid, on membrane conductance in the human airway epithelial cell line H441. Under zero current clamp conditions this hormone induced amiloride-sensitive depolarization of the membrane potential (V(m)). Lowering external(More)
of intermediate-conductance, Ca 2ϩ-activated K ϩ channel (KCNN4) in H441 human distal airway epithelial cells. studies of H441 human distal airway epithelial cells showed that thapsigargin caused a Ca 2ϩ-dependent increase in membrane conductance (GTot) and hyperpolarization of membrane potential (V m). These effects reflected a rapid rise in cellular K ϩ(More)
The human lung small cell adenocarcinoma cell line, A549, demonstrates a concentration-dependent rise in [Ca2+]i in response to extracellular nucleotides. The cells show Ca2+ mobilization on addition of various nucleotides, with an order of agonist potency: UTP > or = ATP > ADP > ADP beta S > AMP; adenosine is ineffective. The EC50 values for UTP and ATP(More)
Electrophysiological studies of H441 human distal airway epithelial cells showed that thapsigargin caused a Ca(2+)-dependent increase in membrane conductance (G(Tot)) and hyperpolarization of membrane potential (V(m)). These effects reflected a rapid rise in cellular K(+) conductance (G(K)) and a slow fall in amiloride-sensitive Na(+) conductance (G(Na)).(More)
BACKGROUND AND PURPOSE Absorptive epithelia express apical receptors that allow nucleotides to inhibit Na(+) transport but ATP unexpectedly stimulated this process in an absorptive cell line derived from human bronchiolar epithelium (H441 cells) whilst UTP consistently caused inhibition. We have therefore examined the pharmacological basis of this anomalous(More)
BACKGROUND Hyperhidrosis is the secretion of inappropriately large amounts of sweat by eccrine glands; it can be very debilitating. Little is known of the causes of primary hyperhidrosis. OBJECTIVES To determine whether the glands exhibit any structural abnormality in primary hyperhidrosis. METHODS Skin biopsies were obtained from the axilla (n = 6) or(More)
ATP and UTP did not evoke [Ca2+]i signals in rat foetal lung epithelial cells grown on glass but elicited clear responses in cells grown into functionally polarised epithelia on permeable supports. Moreover, P2Y2 receptor mRNA could not be detected in cells on glass by the polymerase chain reaction but this mRNA species was clearly expressed by polarised(More)
Apical and basolateral application of ATP and UTP evoked [Ca(2+)](i) and short circuit current (Isc) increases in normal and hyperhidrotic human eccrine sweat gland cells grown into functionally polarised epithelia on permeable supports. Basolateral application to hyperhidrotic cells exhibited a markedly greater increase in Isc than in normal cells.(More)
The presence and cellular distribution of subunits of the V1 sector of the vacuolar-type H+ -ATPase (V-ATPase) was investigated in isolated human eccrine sweat glands. In every instance, V-ATPase was located in the cytoplasm and apical membranes of the luminal cells of the reabsorptive duct segment. In the secretory coil, both diffuse and perinuclear(More)
OBJECTIVE The goal of this study was to determine the prevalence of asthma in school children in the tri-island Caribbean nation of Grenada. SETTING, PARTICIPANTS AND OUTCOMES This was a self-report study provided to the guardians of all primary school children between ages 6 and 7 throughout Grenada, Carriacou and Petite Martinique in 2013. Of the 2362(More)