Immediate effects of standing unstable board intervention on the non-paralyzed leg on sitting balance in severe hemiplegia: a randomized controlled trial.

BACKGROUND: Unstable board intervention for patients with stroke improves sitting balance and trunk function. However, because patients with severe stroke are at high risk of falling, it is mostly adapted in mild cases. OBJECTIVE: We aimed to examine the effect of standing unstable board intervention for the non-paralyzed lower limbs on sitting balance in patients with hemiplegia. METHODS: The participants were 42 patients with stroke who were randomly assigned to a control or intervention group. In the intervention group, the non-paralyzed leg was placed on an unstable board, and the patient wore a knee-ankle-foot orthosis on the paralyzed side and practiced standing and weight-bearing exercises on the unstable board for 3 days. The outcomes were the angle of righting reaction of the neck, trunk, and both lower legs and the movement distance of the center of pressure of the righting reaction from lateral tilted sitting. RESULTS: In the intervention group, the righting reaction angle of the trunk to the paralyzed and non-paralyzed sides and the movement distance of the center of pressure were increased significantly after the unstable board intervention. CONCLUSION: The standing unstable board intervention for the non-paralyzed lower limb increased sensory input to the non-paralyzed side of the trunk weight-bearing on the lower limb of the paralyzed side. The increase in the righting reaction angle and the movement distance of the center of pressure contributed to improved sitting balance.

An Envelope-Modified Tetravalent Dengue Virus-Like-Particle Vaccine Has Implications for Flavivirus Vaccine Design.

Dengue viruses (DENV) infect 50 to 100 million people each year. The spread of DENV-associated infections is one of the most serious public health problems worldwide, as there is no widely available vaccine or specific therapeutic for DENV infections. To address this, we developed a novel tetravalent dengue vaccine by utilizing virus-like particles (VLPs). We created recombinant DENV1 to -4 (DENV1-4) VLPs by coexpressing precursor membrane (prM) and envelope (E) proteins, with an F108A mutation in the fusion loop structure of E to increase the production of VLPs in mammalian cells. Immunization with DENV1-4 VLPs as individual, monovalent vaccines elicited strong neutralization activity against each DENV serotype in mice. For use as a tetravalent vaccine, DENV1-4 VLPs elicited high levels of neutralization activity against all four serotypes simultaneously. The neutralization antibody responses induced by the VLPs were significantly higher than those with DNA or recombinant E protein immunization. Moreover, antibody-dependent enhancement (ADE) was not observed against any serotype at a 1:10 serum dilution. We also demonstrated that the Zika virus (ZIKV) VLP production level was enhanced by introducing the same F108A mutation into the ZIKV envelope protein. Taken together, these results suggest that our strategy for DENV VLP production is applicable to other flavivirus VLP vaccine development, due to the similarity in viral structures, and they describe the promising development of an effective tetravalent vaccine against the prevalent flavivirus.IMPORTANCE Dengue virus poses one of the most serious public health problems worldwide, and the incidence of diseases caused by the virus has increased dramatically. Despite decades of effort, there is no effective treatment against dengue. A safe and potent vaccine against dengue is still needed. We developed a novel tetravalent dengue vaccine by using virus-like particles (VLPs), which are noninfectious because they lack the viral genome. Previous attempts of other groups to use dengue VLPs resulted in generally poor yields. We found that a critical amino acid mutation in the envelope protein enhances the production of VLPs. Our tetravalent vaccine elicited potent neutralizing antibody responses against all four DENV serotypes. Our findings can also be applied to vaccine development against other flaviviruses, such as Zika virus or West Nile virus.

Development of a Novel Virus-Like Particle Vaccine Platform That Mimics the Immature Form of Alphavirus.

Virus-like particles (VLPs) are noninfectious multiprotein structures that are engineered to self-assemble from viral structural proteins. Here, we developed a novel VLP-based vaccine platform utilizing VLPs from the chikungunya virus. We identified two regions within the envelope protein, a structural component of chikungunya, where foreign antigens can be inserted without compromising VLP structure. Our VLP displays 480 copious copies of an inserted antigen on the VLP surface in a highly symmetric manner and is thus capable of inducing strong immune responses against any inserted antigen. Furthermore, by mimicking the structure of the immature form of the virus, we altered our VLP's in vivo dynamics and enhanced its immunogenicity. We used the circumsporozoite protein (CSP) of the Plasmodium falciparum malaria parasite as an antigen and demonstrated that our VLP-based vaccine elicits strong immune responses against CSP in animals. The sera from immunized monkeys protected mice from malaria infection. Likewise, mice vaccinated with P. yoelii CSP-containing VLPs were protected from an infectious sporozoite challenge. Hence, our uniquely engineered VLP platform can serve as a blueprint for the development of vaccines against other pathogens and diseases.

Lubiprostone increases spontaneous bowel movement frequency and quality of life in patients with chronic idiopathic constipation.

BACKGROUND & AIMS: Lubiprostone is an activator of the type 2 chloride channel that facilitates spontaneous bowel movement (SBM). We performed phase 3 studies to determine whether lubiprostone increases the frequency of SBM in patients with chronic idiopathic constipation (CIC) in Japan, and whether long-term administration of lubiprostone increases the quality of life of patients with CIC. METHODS: We performed a randomized, double-blind, placebo-controlled, phase 3 trial of lubiprostone. Patients with CIC (n = 124) were assigned randomly to groups given placebo (n = 62) or lubiprostone (48 µg/day; n = 62) for 4 weeks. The primary efficacy end point was the change from baseline in the weekly average number of SBMs after 1 week of administration. In a long-term study of efficacy and safety, 209 patients with CIC were given lubiprostone (24 µg twice daily) for 48 weeks. RESULTS: Daily administration of lubiprostone induced a significantly greater change, from baseline, in the weekly average number of SBMs at week 1 (increase of 3.7 ± 2.8), compared with placebo (increase of 1.3 ± 1.8; P < .001). The frequency of SBMs during each week of the study period was significantly higher after subjects began receiving lubiprostone than at baseline (P < .0001 at all weeks). Long-term administration of lubiprostone significantly increased scores from the Short-Form health survey and irritable bowel syndrome quality-of-life questionnaire, compared with baseline. We did not observe any severe adverse reactions to lubiprostone. CONCLUSIONS: In phase 3 studies in Japan, lubiprostone increased the weekly average number of SBMs and increased the quality of life of patients with CIC. Clinical Trial Notification of the Japanese Regulatory Authorities: 20-3296 and 20-3300.

A randomized study of lubiprostone for opioid-induced constipation in patients with chronic noncancer pain.

OBJECTIVE: To evaluate the efficacy and safety of oral lubiprostone for relieving symptoms of opioid-induced constipation (OIC) in patients with chronic noncancer pain. DESIGN: Prospective, randomized, double-blind, placebo-controlled trial. SETTING: Seventy-nine US and Canadian centers. SUBJECTS: Patients aged ≥ 18 years with OIC, defined as <3 spontaneous bowel movements (SBMs) per week. METHODS: Patients received lubiprostone 24 mcg or placebo twice daily for 12 weeks. The primary endpoint was change from baseline in SBM frequency at week 8. RESULTS: Among randomized patients (N=418; lubiprostone, N=210; placebo, N=208), most completed the study (lubiprostone, 67.1%; placebo, 69.7%). The safety and efficacy (intent-to-treat) populations included 414 (lubiprostone, N=208; placebo, N=206) and 413 (lubiprostone, N=209; placebo, N=204) patients, respectively. The mean (standard deviation) age was 50.4 (10.9) years; most patients were female (64.4%) and white (77.7%). Changes from baseline in SBM frequency rates were significantly higher at week 8 (P=0.005) and overall (P=0.004) in patients treated with lubiprostone compared with placebo. Pairwise comparisons showed significantly greater overall improvement for abdominal discomfort (P=0.047), straining (P<0.001), constipation severity (P=0.007), and stool consistency (P<0.001) with lubiprostone compared with placebo. Moreover, patients rated the effectiveness of lubiprostone as significantly (P<0.05) better than placebo for 11 of 12 weeks. The most common treatment-related adverse events (AEs) with lubiprostone and placebo were nausea (16.8% vs 5.8%, respectively), diarrhea (9.6% vs 2.9%), and abdominal distention (8.2% vs 2.4%). No lubiprostone-related serious AEs occurred. CONCLUSION: Lubiprostone effectively relieved OIC and associated signs and symptoms and was well tolerated in patients with chronic noncancer pain (http://clinicaltrials.gov/ct2/show/NCT00595946).

Lubiprostone for the treatment of functional constipation in children.

OBJECTIVES: Pediatric functional constipation is common; effective, easily administered treatment options are limited. Lubiprostone is an oral chloride channel protein-2 activator that stimulates gastrointestinal fluid secretion, softens stools, and facilitates bowel movements (BMs). We evaluated the safety and effectiveness of lubiprostone in children and adolescents with functional constipation. METHODS: Patients ≥12 kg, 17 years or younger, and with <3 spontaneous BMs (SBMs; ie, BMs that did not occur within 24 hours of rescue medication use) per week were enrolled at 22 US general pediatric and pediatric gastroenterology centers (January 2007-October 2008). Patients received 4 weeks of open-label lubiprostone at doses of 12 µg once daily (QD), 12 µg twice daily (BID), or 24 µg BID based on age and weight. The primary endpoint was SBM frequency during week 1 versus baseline. RESULTS: Of 127 enrolled patients, 124 were treated and analyzed (12 µg QD, n = 27; 12 µg BID, n = 65; 24 µg BID, n = 32), and 109 completed the study. The mean age of treated patients was 10.2 years (range 3-17 years); 65 were boys. Mean SBM frequency significantly increased compared with baseline at week 1 (3.1 vs. 1.5 SBMs/week, P < 0.0001). SBM frequency was improved significantly from baseline overall (P < 0.0001) and for individual dose groups (P ≤ 0.0062) during weeks 2, 3, and 4. Common (≥5%) adverse events included nausea (18.5%), vomiting (12.1%), diarrhea (8.1%), abdominal pain (7.3%), and headache (5.6%). Two patients experienced serious adverse events (unrelated abdominal pain; unrelated sickle cell crisis). CONCLUSIONS: Lubiprostone was efficacious and well tolerated in children and adolescents with functional constipation.

Gastro protective properties of the novel prostone SPI-8811 against acid-injured porcine mucosa.

AIM: To evaluate the protective properties of novel prostone ClC-2 agonist SPI-8811 in porcine model of gastric acid injury. METHODS: Porcine gastric mucosa was mounted in Ussing chambers and injured by bathing mucosal tissues in an HCl Ringer's solution (pH = 1.5) with or without SP1-8811 (1 µmol/L), cystic fibrosis transmembrane conductance regulator (CFTR) inhibitor (inhibitor 172, 10 µmol/L, apical) and ClC-2 inhibitor ZnCl2, 300 µmol/L, apical), on the apical surface of tissues. Transepithelial resistance and mucosal-to-serosal ³H-mannitol fluxes were measured over a 90-min period. Tissues were analyzed by morph metric techniques, Immunofluorescence and by western blots. RESULTS: Compared with control tissues, acid exposure decreased transepithelial electrical resistance (TER) and increased ³H-mannitol flux. Pretreatment of gastric mucosa with SPI-8811 was protective against acid-induced decreases in TER (TER, 50 Ω.cm² vs 100 Ω.cm²) and abolished increases in flux (³H-mannitol flux, 0.10 µmol/L.cm² vs 0.04 µmol/L.cm²). Evidence of histological damage in the presence of acid was markedly attenuated by SPI-0811. Immunofluorescence and western analysis for occludin revealed enhanced localization to the region of the tight junction (TJ) after treatment with SPI-8811. Pretreatment with the ClC-2 inhibitor ZnCl2, but not the selective CFTR inhibitor 172, attenuated SPI-8811-mediated mucosal protection, suggesting a role for ClC-2. Prostone may serve both protective and reparative roles in injured tissues. CONCLUSION: ClC-2 agonist SPI-8811 stimulated enhancement of mucosal barrier function by protecting TJ protein occludin in porcine gastric mucosa and thus protected the gastric acid injury in porcine stomach.

Unoprostone isopropyl and metabolite M1 activate BK channels and prevent ET-1-induced [Ca²âº]i increases in human trabecular meshwork and smooth muscle.

PURPOSE: Effects of cis-unoprostone isopropyl, its primary metabolite M1, trans-unoprostone isopropyl, latanoprost free acid, and fluprostenol were studied on Ca(2+)-activated K(+) (BK) channels, plasma membrane potential, [cAMP](i), [cGMP](i), and steady state [Ca(2+)](i), and protection against endothelin-1 (ET-1)-induced steady state [Ca(2+)](i) increases in human cortical neuronal (HCN-1A), trabecular meshwork (HTMC), and pulmonary artery smooth muscle (PASMC) cells. Effects on recombinant human prostaglandin (PG) receptors were determined. METHODS: BK channel currents were measured using whole-cell patch clamp; [cAMP](i), [cGMP](i) with ELISAs; [Ca(2+)](i) with indo-1; plasma membrane potential using diBAC(4)(3); and PG receptor effects with PG receptor-expressing cells and FLIPR fluo-4 Ca(2+) assays. RESULTS: Unoprostone isopropyl and M1 activated sustained iberiotoxin (IbTX)-sensitive, AL-8810 (FP receptor antagonist)-insensitive BK channel currents with EC(50)s of 0.51 ± 0.03 nM (n = 5) and 0.52 ± 0.03 nM (n = 6) in HTMCs; 0.61 ± 0.06 nM (n = 8) and 0.46 ± 0.04 nM (n = 5) for M1 in HCN-1A cells and PASMC, respectively. They caused AL-8810-insensitive, IbTX-sensitive membrane hyperpolarization at 10 nM; up to 100 nM had no effect on or decreased [cAMP](i), [cGMP](i), and [Ca(2+)](i); and prevented ET-1-induced [Ca(2+)](i) increases. In contrast, 10 nM latanoprost free acid and fluprostenol caused membrane depolarization; increased [cAMP](i), [cGMP](i), and [Ca(2+)](i); and did not prevent ET-1-induced [Ca(2+)](i) increases. Trans-unoprostone isopropyl had no effects. Unoprostone isopropyl (1.25 µM) had no effect on PG receptors, and neither did M1, except for activating the FP receptor with EC(50) = 557.9 ± 55.2 nM (n = 4). CONCLUSIONS: Prostones, unoprostone isopropyl and M1, are potent AL-8810-insensitive, stereospecific BK channel activators, without [cAMP](i), [cGMP](i), or [Ca(2+)](i) involvement, and prevent ET-1-induced steady state Ca(2+) increases in HTMCs.

Long-term safety and effectiveness of lubiprostone, a chloride channel (ClC-2) activator, in patients with chronic idiopathic constipation.

BACKGROUND: Lubiprostone helps relieve constipation in short-term 4-week studies. There are limited data on long-term pharmacological treatment with lubiprostone for chronic idiopathic constipation. AIMS: To examine the long-term safety and effectiveness of lubiprostone in patients with chronic idiopathic constipation. METHODS: In this prospective, multicenter, open-labeled trial, 248 patients aged ≥18 years with chronic idiopathic constipation were directed to take lubiprostone 24 mcg BID as needed for 48 weeks. Patients were allowed to decrease the dose in response to the perceived severity of constipation and need for relief. Hematology and chemistry profiles and assessment of constipation symptoms and its severity were performed at all visits. Adverse events (AEs) were recorded. RESULTS: Of the 248 patients who entered the trial, 127 (51%) completed the trial. A dose reduction was observed in 17% of the patients, resulting in an average study medication exposure across the study of approximately 1.7 capsules (or approximately 40.8 mcg) per day. The most common treatment-related AEs were nausea (19.8%), diarrhea (9.7%), abdominal distension (6.9%), headache (6.9%), and abdominal pain (5.2%). No deaths were reported and of the 16 reported serious AEs, one was considered possibly treatment related. Average changes in serum electrolytes were not clinically relevant at any time point during the study. On average, lubiprostone significantly (p < 0.0001) reduced patient-reported constipation severity, abdominal bloating, and abdominal discomfort across 48 weeks when compared to baseline. CONCLUSIONS: During this 48-week open-label study, lubiprostone was well tolerated. Bowel symptoms consistently improved over 48 weeks in adult patients with chronic idiopathic constipation.

Lubiprostone reverses the inhibitory action of morphine on mucosal secretion in human small intestine.

BACKGROUND AND AIMS: Treatments with morphine or opioid agonists cause constipation. Lubiprostone is approved for treatment of adult idiopathic constipation and constipation-predominant IBS in adult women. We tested whether lubiprostone can reverse morphine-suppression of mucosal secretion in human intestine and explored the mechanism of action. METHODS: Fresh segments of jejunum discarded during Roux-En-Y gastric bypass surgeries were used. Changes in short-circuit current (ΔIsc) were recorded in Ussing flux chambers as a marker for electrogenic chloride secretion during pharmacological interactions between morphine, prostaglandin receptor antagonists, chloride channel blockers and lubiprostone. RESULTS: Morphine suppressed basal Isc. Lubiprostone reversed morphine suppression of basal Isc. Lubiprostone, applied to the mucosa in concentrations ranging from 3 nM to 30 µM, evoked increases in Isc in concentration-dependent manner when applied to the mucosal side of muscle-stripped preparations. Blockade of enteric nerves did not change stimulation of Isc by lubiprostone. Removal of chloride or application of bumetanide or NPPB suppressed or abolished responses to lubiprostone. Antagonists acting at CFTR channels and prostaglandin EP(4) receptors, but not at E(1), EP(1-3) receptors, partially suppressed stimulation of Isc by lubiprostone. CONCLUSIONS: Antisecretory action of morphine results from suppression of excitability of secretomotor neurons in the enteric nervous system. Lubiprostone, which does not affect enteric neurons directly, bypasses the action of morphine by directly opening mucosal chloride channels.

An odontometric study of the maxillary molars in Australian marsupials. I. The koala (Phascolarctos cinereus).

Crown dimensions of the maxillary molars were measured in the koala (Phascolarctos cinereus). There were no significant differences in crown diameters between the first and second molars, however the fourth molars were reduced in all crown diameters. The third molar was smaller than the first or second molars in buccolingual crown diameters but there were no significant differences in mesiodistal crown diameters. It is proposed that the similar shapes of the first and second molars are associated with similar types of masticatory activity involving these teeth, The shape of the third molar, which is reduced in size buccolingually, may be linked to the koala's occlusal function which is characterized by a condylar action that leads to differences in movement between opposing anterior and posterior molar teeth during the occlusal stroke. The fourth molar, the smallest of the molar teeth in crown diameter, erupts significantly later than the other molars, and its reduction may be explained by the terminal and distal reduction theories. It is proposed that the pattern of molar morphology in the koala is associated with both masticatory activity linked to its characteristic occlusal function, as well as reflecting the sequence of tooth emergence.

Efficacy and safety of lubiprostone in patients with chronic constipation.

AIMS: The aim of this study is to assess the efficacy and safety of lubiprostone in adults with chronic constipation. METHODS: This multicenter, parallel-group trial enrolled 237 patients with chronic constipation and randomized them to 4 weeks of double-blind treatment with oral lubiprostone 24 mcg or placebo twice daily. The primary efficacy endpoint was the number of spontaneous bowel movements (SBMs) after 1 week of treatment. Secondary evaluations included SBMs at weeks 2, 3, and 4; percentage of patients with a SBM within 24 h of first study dose; stool consistency; degree of straining; constipation severity; abdominal bloating and discomfort; global treatment effectiveness; and safety assessments. RESULTS: Lubiprostone-treated patients experienced greater mean numbers of SBMs at week 1 compared with placebo (5.89 versus 3.99, P = 0.0001), with significantly greater percentages having SBMs within 24 h of the first dose (61.3% versus 31.4%, P < 0.0001). At each assessment, SBM frequency and percentages of full responders (> or =4 SBM per week) were significantly greater among lubiprostone-treated patients compared with placebo (P < or = 0.0171). Lubiprostone-treated patients reported significant improvements in stool consistency, straining, and constipation severity at all weeks, and in abdominal bloating at week 1. Patient assessments of treatment effectiveness were significantly greater with lubiprostone compared with placebo at all weeks (P < 0.0004). Gastrointestinal-related disorders were the most common adverse events in both treatment groups. CONCLUSIONS: In patients with chronic constipation, lubiprostone produced a bowel movement in the majority of individuals within 24 h of initial dosing, with sustained improvement in frequency as well as other constipation symptoms over 4 weeks of treatment.

Differential gene expression in black tiger shrimp, Penaeus monodon, following administration of oxytetracycline and oxolinic acid.

The intensification of shrimp farming systems has led to the spreading of a variety of bacterial and viral diseases that continue to plague the shrimp industry worldwide. Efforts to combat these pathogenic organisms include the use of immunostimulants, probiotics, vaccines and antibiotics. Although a few studies have already reported on the effects of various stimuli on shrimp, the effect of antibiotics, particularly on the changes in the shrimp transcriptomic profile have yet to be reported. Here we show that injecting shrimp with oxytetracycline and oxolinic acid alters the expression of genes in the black tiger shrimp, Penaeus monodon, lymphoid organ. These antibiotics, especially oxylinic acid, down-regulated the expression of a few immune-related genes, most notably penaeidin, proPO, clotting protein, profilin and whey acidic protein.

Comparison of the chloride channel activator lubiprostone and the oral laxative Polyethylene Glycol 3350 on mucosal barrier repair in ischemic-injured porcine intestine.

AIM: To investigate the effects of lubiprostone and Polyethylene Glycol 3350 (PEG) on mucosal barrier repair in ischemic-injured porcine intestine. METHODS: Ileum from 6 piglets (approximately 15 kg body weight) was subjected to ischemic conditions by occluding the local mesenteric circulation for 45 min in vivo. Ileal tissues from each pig were then harvested and mounted in Ussing chambers and bathed in oxygenated Ringer's solution in vitro. Intestinal barrier function was assessed by measuring transepithelial electrical resistance (TER) and mucosal-to-serosal fluxes of (3)H-mannitol and (14)C-inulin. Statistical analyses of data collected over a 120-min time course included 2-way ANOVA for the effects of time and treatment on indices of barrier function. RESULTS: Application of 1 micromol/L lubiprostone to the mucosal surface of ischemic-injured ileum in vitro induced significant elevations in TER compared to non-treated tissue. Lubiprostone also reduced mucosal-to-serosal fluxes of (3)H-mannitol and (14)C-inulin. Alternatively, application of a polyethylene laxative (PEG, 20 mmol/L) to the mucosal surface of ischemic tissues significantly increased flux of (3)H-mannitol and (14)C-inulin. CONCLUSION: This experiment demonstrates that lubiprostone stimulates recovery of barrier function in ischemic intestinal tissues whereas the PEG laxative had deleterious effects on mucosal repair. These results suggest that, unlike osmotic laxatives, lubiprostone stimulates repair of the injured intestinal barrier.

A synthetic prostone activates apical chloride channels in A6 epithelial cells.

The bicyclic fatty acid lubiprostone (formerly known as SPI-0211) activates two types of anion channels in A6 cells. Both channel types are rarely, if ever, observed in untreated cells. The first channel type was activated at low concentrations of lubiprostone (<100 nM) in >80% of cell-attached patches and had a unit conductance of approximately 3-4 pS. The second channel type required higher concentrations (>100 nM) of lubiprostone to activate, was observed in approximately 30% of patches, and had a unit conductance of 8-9 pS. The properties of the first type of channel were consistent with ClC-2 and the second with CFTR. ClC-2's unit current strongly inwardly rectified that could be best fit by models of the channel with multiple energy barrier and multiple anion binding sites in the conductance pore. The open probability and mean open time of ClC-2 was voltage dependent, decreasing dramatically as the patches were depolarized. The order of anion selectivity for ClC-2 was Cl > Br > NO(3) > I > SCN, where SCN is thiocyanate. ClC-2 was a "double-barreled" channel favoring even numbers of levels over odd numbers as if the channel protein had two conductance pathways that opened independently of one another. The channel could be, at least, partially blocked by glibenclamide. The properties of the channel in A6 cells were indistinguishable from ClC-2 channels stably transfected in HEK293 cells. CFTR in the patches had a selectivity of Cl > Br >> NO(3) congruent with SCN congruent with I. It outwardly rectified as expected for a single-site anion channel. Because of its properties, ClC-2 is uniquely suitable to promote anion secretion with little anion reabsorption. CFTR, on the other hand, could promote either reabsorption or secretion depending on the anion driving forces.

Effects of lubiprostone on human uterine smooth muscle cells.

Lubiprostone, a bicyclic fatty acid derivative and member of a new class of compounds called prostones, locally activates ClC-2 Cl(-) channels without activation of prostaglandin receptors. The present study was specifically designed to test and compare lubiprostone and prostaglandin effects at the cellular level using human uterine smooth muscle cells. Effects on [Ca(2+)](i), membrane potential and [cAMP](i) in human uterine smooth muscle cells were measured. 10 nM lubiprostone significantly decreased [Ca(2+)](i) from 188 to 27 nM, which was unaffected by 100 nM SC-51322, a prostaglandin EP receptor antagonist. In contrast 10nM PGE(2) and PGE(1) both increased [Ca(2+)](i) 3-5-fold which was blocked by SC-51322. Similarly, lubiprostone and prostaglandins had opposite/different effects on membrane potential and [cAMP](i). Lubiprostone caused SC-51322-insensitive membrane hyperpolarization and no effect on [cAMP](i). PGE(2) and PGE(1) both caused SC-51322-sensitive membrane depolarization and increased [cAMP](i). Lubiprostone has fundamentally different cellular effects from prostaglandins that are not mediated by EP receptors.

Multicenter, 4-week, double-blind, randomized, placebo-controlled trial of lubiprostone, a locally-acting type-2 chloride channel activator, in patients with chronic constipation.

OBJECTIVES: To assess the efficacy and safety of lubiprostone in adults with chronic constipation. METHODS: This multicenter, parallel-group, double-blind controlled trial enrolled 242 patients with constipation and randomized them to receive oral lubiprostone 24 mcg or placebo twice daily for 4 wk. The primary efficacy end point was the number of spontaneous bowel movements (SBMs; those occurring without use of constipation relieving medications) after 1 wk of double-blind treatment. Other evaluations included SBMs at weeks 2, 3, and 4; bowel movement (BM) characteristics (i.e., consistency and straining); constipation severity; abdominal bloating/discomfort; global treatment effectiveness ratings; and safety assessments. RESULTS: The 120 lubiprostone-treated patients reported a greater mean number of SBMs at week 1 compared with the 122 placebo-treated patients (5.69 vs 3.46, P= 0.0001), with a greater frequency of SBMs also reported at weeks 2, 3, and 4 (P