Characterisation of colistin resistance in Gram-negative microbiota of pregnant women and neonates in Nigeria

A mobile colistin resistance gene mcr was first reported in 2016 in China and has since been found with increasing prevalence across South-East Asia. Here we survey the presence of mcr genes in 4907 rectal swabs from mothers and neonates from three hospital sites across Nigeria; a country with limited availability or history of colistin use clinically. Forty mother and seven neonatal swabs carried mcr genes in a range of bacterial species: 46 Enterobacter spp. and single isolates of; Shigella, E. coli and Klebsiella quasipneumoniae. Ninety percent of the genes were mcr-10 (n = 45) we also found mcr-1 (n = 3) and mcr-9 (n = 1). While the prevalence during this collection (2015-2016) was low, the widespread diversity of mcr-gene type and range of bacterial species in this sentinel population sampling is concerning. It suggests that agricultural colistin use was likely encouraging sustainment of mcr-positive isolates in the community and implementation of medical colistin use will rapidly select and expand resistant isolates.

Phase II trial of irinotecan, carboplatin, and bevacizumab in patients with limited-stage small cell lung cancer

18133

Background: In a previously reported phase II trial bevacizumab (B) was used as maintenance therapy following induction with irinotecan (I), carboplatin (C) and radiotherapy (RT) in patients (pts) with limited-stage small-cell lung cancer (LS-SCLC). 1-year progression- free survival (PFS) and overall survival (OS) were 53% and 70%, respectively. In the present multicenter community-based trial B is given with induction chemoradiotherapy and as maintenance therapy. Methods: The primary endpoint is to assess the median PFS. Eligibility criteria: newly diagnosed LS-SCLC, measurable disease, ECOG PS 0–1, and informed consent. Exclusion criteria: hemoptysis and therapeutic anticoagulation. Treatment: I 60mg/m2 IV D1, 8, 15, C AUC=4 IV D1, and B 10 mg/kg IV D1 and 15 every 28D. Pts received concurrent RT to 61.2 Gy starting with the 3rd cycle, and were restaged every 8 weeks. If no progressive disease (PD) or excessive toxicity after 4 cycles, pts received B x 6 months. Prophylactic cranial irradiation was used at M.D. discretion. This 2-stage trial was designed to achieve a 40% improvement in historical median PFS of 12–14 months. Results: 20 pts were enrolled from 4/06 to 12/06 (trial ongoing, n=50 planned). Data are available for 14 pts in this analysis. Baseline features: median age 64 years; male/female, 21%/79%; and ECOG PS 0/1, 64%/36%. The objective response rate was 78% (95% CI 45%-94%) - all partial responses. No pt had PD. 7 pts were not evaluable: too early, 5 pts; off study (toxic megacolon, 1 pt; intercurrent illness, 1 pt). With a median follow-up of 5 months, the median PFS has not been reached. Grade (G) 3/4 non-hematologic toxicity with induction occurring in more than 2 pts: diarrhea (29%) and esophagitis, fatigue, pain (21% each). G3/4 hematologic toxicity: leukopenia (21%), neutropenia (14%), and thrombocytopenia (43%). There have been 2 G3/4 bleeding events with induction: suspected tracheoesophageal fistula with death (possibly treatment-related), 1 pt; and hematochezia, unrelated, 1 pt. Conclusions: This trial continues to be closely monitored for safety. Further accrual and longer follow-up are necessary to assess if B can be safely combined with chemoradiotherapy and improve efficacy.

No significant financial relationships to disclose.

Weekly docetaxel versus docetaxel/gemcitabine in elderly/poor performance status (PS) patients (pts) with stage IIIB/IV non-small cell lung cancer (NSCLC): Randomized phase III trial of the Minnie Pearl Cancer Research Network

7534

Background: Standard treatment for pts with good PS stage IIIB/IV NSCLC currently includes a two-drug platinum-based chemotherapy regimen. Optimum treatment for elderly and/or poor PS pts is less well defined, with some studies showing comparable efficacy/decreased toxicity with single agent treatment. In this randomized phase III trial we compared single agent weekly docetaxel with the combination of docetaxel/gemcitabine. Methods: Between 8/01 and 3/06, 350 pts were enrolled from 39 sites. Eligibility: previously untreated stage IIIB/IV NSCLC; age = 65 years and/or ECOG PS2; measurable disease; no active CNS metastases; adequate kidney, liver, marrow function; informed consent. Pts were randomized to receive docetaxel (36 mg/m2 IV days 1, 8, 15; repeated every 28 days) or docetaxel (30 mg/m2)/gemcitabine (800 mg/m2) both given days 1, 8, 15 of a 28-day cycle. Pts were reevaluated after 8 weeks; responders continued treatment for 6 cycles or until disease progression. Accrual of 330 evaluable pts allowed detection of improvement in 1-year survival from 25% (expected with weekly docetaxel) to 40% (significance level 0.05, power 0.8). Results: Clinical features of pts receiving docetaxel/gemcitabine (n=174) vs. weekly docetaxel (n=171) were similar; 19% were ECOG PS2, and 38% were > 75 years old. After a median follow-up of 22 months, there were no differences between docetaxel/gemcitabine vs weekly docetaxel in median survival (5.6 vs. 5.1 months; p=0.65) or 1-year survival (26% vs. 24%). TTP was prolonged with docetaxel/gemcitabine vs. docetaxel (4.8 months vs. 2.9 months; p=0.0004). Response rates: docetaxel/gemcitabine 25%; docetaxel 17%. Both regimens were well tolerated by most pts; grade 3/4 neutropenia, thrombocytopenia, and anemia were more frequent with docetaxel/gemcitabine. Conclusions: These two regimens have similar efficacy in these elderly/poor PS pts; weekly docetaxel produced less myelosuppression. However, these results in this relatively unselected community-based population emphasize the need for novel treatment approaches.

No significant financial relationships to disclose.

Phase II trial of vinflunine in patients with relapsed small cell lung cancer

18091

Background: Vinflunine (VFL) is a novel microtubule inhibitor of the vinca alkaloid class which has demonstrated significant preclinical activity in a small cell lung cancer (SCLC) model and antitumor activity in several other tumor types. This multicenter community- based trial was designed to examine the role of VFL in patients (pts) with relapsed SCLC. Methods: The primary endpoint is objective response rate (ORR). Eligibility criteria: previously treated SCLC (sensitive or refractory relapsed pts; limited to 1 prior platinum or non-platinum therapy for limited- or extensive-stage disease), ECOG PS 0–2, measurable disease, and informed consent. Treatment: VFL 320 mg/m2 IV over 20 minutes day 1 every 21 days for up to 6 cycles. Pts were restaged every 6 weeks. This 2-stage trial was designed to achieve a 20% ORR in platinum-sensitive pts (per RECIST criteria). Results: 29 pts were enrolled from 3/06 to 12/06 (trial ongoing, n=41 planned). Data are available for 16 pts in this analysis. Baseline characteristics: median age 64 years; male/female, 63%/37%; ECOG PS 0/1/2, 25%/50%/25%; and sensitive relapse, 50%. 3 partial response have been observed (ORR 19%, 95% CI 4%-46%). 3 pts (19%) had stable disease and 7 pts (44%) had progressive disease. 3 pts were not evaluable due to: treatment-related toxicity (sepsis; constipation); declining PS, 1 pt each. With a median follow-up of 5 months, the median progression-free survival and overall survival are 1.7 months and 3.6 months, respectively. Grade (G) 3/4 non-hematologic toxicity occurring in more than 1 pt: constipation, dyspnea, fatigue, and hyponatremia (13% each). G3/4 hematologic toxicity: leukopenia (44%), neutropenia (38%), and thrombocytopenia (6%). There have been no treatment-related deaths. Conclusions: VFL appears active as second-line treatment for SCLC. Additional assessment of myelosuppression is needed to better assess VFL’s role. Completion of accrual is anticipated by 4/07.

No significant financial relationships to disclose.

Phase II trial of irinotecan, carboplatin, and bevacizumab in patients with extensive-stage small cell lung cancer

18130

Background: Bevacizumab (B) improves survival when combined with chemotherapy in non-small cell lung cancer treatment. Our center previously studied the role of B as maintenance therapy in patients (pts) with limited-stage small cell lung cancer (SCLC). The present multicenter community-based trial was designed to examine the role of B and chemotherapy in previously untreated pts with extensive- stage SCLC (ES-SCLC). Methods: The primary endpoint is to assess the median time to progression (TTP). Eligibility criteria: untreated ES-SCLC, ECOG PS 0–1, measurable disease, and informed consent. Exclusion criteria: hemoptysis, brain metastases, and therapeutic anticoagulation. Treatment: irinotecan (I) 60 mg/m2 IV D1, 8, 15, and carboplatin (C) AUC=4 IV D1, and B 10 mg/kg IV D1 and 15 every 28D. Pts were restaged every 8 weeks. If no evidence of progressive disease (PD) after 4–6 cycles, pts received B x 6 months. This 2- stage trial was designed to achieve a 40% improvement in historical median TTP of 6 months. Results: 34 pts were enrolled from 2/06 to 12/06 (trial ongoing, n=50 planned). Data are available for 23 pts in this analysis. Baseline characteristics: median age 66 years; male/female, 52%/48%; and ECOG PS 0/1, 35%/65%. The objective response rate was 78% (95% CI 58%-90%), all partial responses. One pt had stable disease and no pts had PD. Four pts were not evaluable due to: comorbidity (off study), 2 pts; too early, 2 pts. With a median follow-up of 7 months, the median TTP and overall survival have not been reached. Grade (G) 3/4 non-hematologic toxicity: diarrhea (26%), hyponatremia, pain, arthralgia, fatigue (13% each), and dehydration, confusion, proteinuria (9% each). G3/4 hematologic toxicity was limited to neutropenia (13%). Other G3/4 toxicities were = 5%. There have been no episodes of G3/4 bleeding or treatment-related deaths. Conclusions: I/C/B appears to be safe and generally well tolerated in pts with ES-SCLC in this preliminary analysis. Further accrual and longer follow-up are necessary to assess median TTP.

No significant financial relationships to disclose.

Phase I/II trial of preoperative oxaliplatin, docetaxel, capecitabine, and radiation for localized esophageal cancer

4595

Background: Preoperative chemoradiotherapy is a primary treatment option for patients (pts) with resectable esophageal cancer. Combination regimens using newer agents may improve pt outcomes. This multicenter community-based trial examined a modern triplet regimen comprised of oxaliplatin (O), docetaxel (D), and capecitabine (C) combined with radiation (RT). Methods: The primary endpoints were objective response rate (ORR) and safety. Eligibility criteria: pts with resectable stage I-III cancer of the mid-/distal-esophagus or gastroesophageal junction, measurable disease, ECOG PS 0–1, and informed consent. Treatment: O 40 mg/m2 IV and D 20 mg/m2 IV weekly x 5; C 1,000 mg/m2 PO twice daily D1–7, 15–21, 29–35; and concurrent RT to 45 Gy. Pts were resected 4–8 weeks later. O/D/RT safety was determined in a phase I portion (n=10) before adding C in a phase II portion. Results: 43 pts were enrolled from 9/04 to 12/06 (trial ongoing, n=60 planned). Data on 38 pts are available for analysis. Baseline characteristics: median age 61 years; male/female, 76%/24%; ECOG PS 0/1, 32%/68%; adenocarcinoma/squamous, 74%/26%; and stage I, II, III, 8%/45%/47%. The ORR was 58% (95% CI 42%-72%), with 4 complete and 18 partial responses. 37% had stable disease, and 1 pt had progressive disease (PD). 26 pts (68%) were resected. Unresected pts: awaiting surgery, 3 pts; poor PS, 4 pts; PD, 1 pt; pt choice, 1 pt; death, 3 pts. Pathologic complete responses were seen in 17 pts (65%). With a median follow-up of 16 months, 1-year progression-free survival (PFS) and overall survival (OS) are 58% and 64%, respectively. Median PFS and OS have not been reached. Grade (G) 3/4 non-hematologic toxicity: anorexia (21%), dehydration, esophagitis (16% each), nausea (13%), and dysphagia, fatigue, vomiting, and pain (11% each). Other G3/4 non- hematologic toxicities were = 5%. No G3/4 hematologic toxicities or treatment-related deaths occurred. Conclusions: O/D/C/RT appears safe and active as a preoperative regimen for resectable esophageal cancer - with a G3/4 esophagitis rate that compares favorably with historical combination regimens. Additional accrual and follow-up are needed to determine if these benefits are sustained.

No significant financial relationships to disclose.

Weekly bortezomib in the treatment of patients (pts) with previously treated multiple myeloma: A phase II trial of the Minnie Pearl Cancer Research Network

7547

Background: Bortezomib, administered on a twice-weekly schedule, is now a standard part of treatment for patients with multiple myeloma. Weekly bortezomib schedules have shown activity in other cancer types, and are more convenient than twice weekly schedules. In this multicenter, community-based phase II trial, we evaluate the feasibility, toxicity, and efficacy of weekly bortezomib in pts with previously treated multiple myeloma. Methods: Eligibility criteria included a diagnosis of multiple myeloma treated with 1 or 2 previous systemic regimens (only 1 if first-line therapy included high-dose therapy); ECOG PS 0–2; creatinine < 2.0 mg/dL; WBC ≥ 3000/μL; ANC > 1000/μL; platelets ≥ 50,000/μL; no peripheral neuropathy > grade 1; informed consent. All pts received bortezomib 1.6mg/m2 IV on days 1, 8, 15, and 22 of each 5-week cycle. Pts were reevaluated at 10-week intervals; treatment continued for 8 cycles (40 weeks) or until myeloma progression. Results: Between 5/04 and 12/05, 37 pts entered this trial. Pt characteristics: median age 70 years; male/female, 20/17; 24 pts (65%) had received 2 previous regimens (previous high dose therapy, 2 pts); elevated β-2 microglobulin, 27 pts (73%). Of 26 pts evaluated, 13 pts (50%) had major responses, 11 pts (42%) stable disease, and 2 pts (8%) had progression. After a median follow-up of 7 months, projected median PFS is 9.6 months; overall survival at 1 year is 81%. Weekly bortezomib was well tolerated by most pts. Grade 3/4 toxicities included fatigue (21%), diarrhea (11%), neutropenia (7%), thrombocytopenia (4%), all others < 5%. No grade 3/4 neuropathy occurred. Only 1 pt required bortezomib dose reduction during treatment, and 2 pts discontinued treatment because of toxicity (myelosuppression, 1; fatigue/dehydration, 1). Conclusions: Weekly bortezomib is a convenient, well tolerated treatment for pts with previously treated multiple myeloma. Overall response rates with this schedule are similar to those previously reported with the standard twice-weekly schedule. Further followup is necessary to better evaluate the duration of response and the incidence of cumulative toxicities.

[Table: see text]

Preoperative oxaliplatin (O), docetaxel (D), capecitabine (C), and concurrent radiation therapy (RT) for patients (pts) with localized esophageal cancer: A phase I/II trial of the Minnie Pearl Cancer Research Network

4058

Background: Preoperative chemoradiotherapy improves outcomes for pts with resectable esophageal cancer compared with surgery alone. We previously reported a 41% 3-year progression-free survival (PFS) with preoperative paclitaxel/carboplatin/5FU/RT in a large phase II trial. The present multicenter community trial examined the role of a newer combination regimen. Methods: The primary endpoints were to assess the safety and response rate (RR) of O/D/C/RT in pts with resectable stage I-III cancer of the mid-/distal-esophagus or GE junction. Treatment (tx): O 40 mg/m2 IV and D 20 mg/m2 IV weekly x 5; C 1000 mg/m2 PO BID D1–7, 15–21, 29–35; and RT 45 Gy, 1.8-Gy M-F weekly x 5, starting D1. Pts were resected 4–8 weeks after tx. The phase I portion (n=10) confirmed the safety of O/D/R, and C was added in the phase II portion. Eligibility: measurable disease; ECOG PS 0–1, informed consent. Analysis was by intent to treat. Results: Nineteen pts were enrolled from 9/04 to 10/05 (trial ongoing). Baseline features: median age 60 years (38–77); male/female, 82%/18%; ECOG PS 0/1: 27%/73%; adenocarcinoma/squamous (77%/23%); I (5%), IIA (5%), IIB (33%), III (38%), primary tumor not assessable (19%). All pts completed O/D/C/RT and 14 (74%) were resected. Grade (G) 3/4 non-hematologic toxicity: anorexia (16%), nausea (16%), and fatigue (11%). Other G3/4 non-hematologic toxicities were ≤5%, with no G3/4 esophagitis. No G3/4 hematologic toxicities or tx-related deaths occurred. Complete/partial responses assessed before surgery were seen in 2 pts/11 pts, respectively, for an overall RR of 68% (95% CI 46%-84%). Four pts (21%) had stable disease and 1 pt had progression (1 pt was unevaluable). Pathological complete responses were seen in 8 of 14 evaluable pts (57%). With a median follow-up of 8 months, actuarial 1-year PFS and overall survival (OS) are 66% and 79%, respectively. Median PFS and OS have not been reached. Conclusions: O/D/C/RT is a relatively well-tolerated and active preoperative therapy for pts with resectable esophageal cancer. Additional pts and follow-up are needed to assess this regimen’s benefits.

[Table: see text]

Brief duration rituximab(R)/chemotherapy (CNOP or CVP) followed by maintenance rituximab in elderly/poor performance status patients (pts) with diffuse large B-cell lymphoma (DLBCL): A phase II trial of the Minnie Pearl Cancer Research Network

7577

Background: R-CHOP is the standard first-line treatment for pts with DLBCL; however, some pts are poor candidates due to general debility, cardiac disease, or other medical problems. Maintenance R is not effective after full course R-CHOP chemotherapy for DLBCL (ECOG 4494), but improves outcome following CHOP alone. In this phase II trial, we evaluated short course R/chemotherapy, followed by maintenance R, in pts who were not candidates for full-course R-CHOP. Methods: Eligibility: previously untreated DLBCL; stage II-IV; ECOG PS 0–2; age ≥ 70 years or poor CHOP candidate; adequate kidney, liver, bone marrow function; no HIV infection; informed consent. Pts received 3 courses of R-CNOP (cyclophosphamide 500mg/m2, mitoxantrone 10mg/m2, vincristine 1.0mg/m2, prednisone 80mg PO days 1–5, rituximab 375mg/m2) followed by pegfilgrastim 6mg sq day 2, at 21-day intervals. Mitoxantrone was omitted for pts with EF < 40%. Pts with response/stable disease after chemotherapy began maintenance R (375mg/m2 weekly × 4 doses, administered at 6-month intervals × 4 courses). Results: 31 pts entered this trial between 5/03 and 11/05. Clinical characteristics: median age, 78 years; ECOG PS 2, 45%; IPI 3–5, 79%. 27 pts (87%) have completed short course R-chemotherapy; 20 pts (65%) are currently receiving maintenance R. After completion of R-chemotherapy, 17 pts (63%) had responses (9 CR/CRu, 8 PR); 10 pts had stable disease/minor response. After median 16 month follow-up, 29 of 31 pts (94%) are progression-free; actuarial 2-year PFS is 90%. The 2-year overall survival is 74%. 4 pts have died (progressive lymphoma 2, intercurrent illnesses 2). Grade 3/4 toxicities: neutropenia 38%, other toxicities < 10%, no treatment-related deaths. Conclusions: Short-course R-chemotherapy followed by maintenance R was active and well tolerated in a group of elderly, poor prognosis pts with DLBCL. In spite of modest CR/CRu rate; the 90% 2-year PFS suggests a role for maintenance R. If these findings persist with further followup, this approach is worthy of further study in this patient group.

[Table: see text]

Parameterization of the shape of intracranial saccular aneurysms using Legendre polynomials

Our recent studies of the nonlinear mechanics of saccular aneurysms suggest that it is unlikely that these lesions enlarge or rupture via material (limit point) or dynamic (resonance) instabilities. Rather, there is a growing body of evidence from both vascular biology and biomechanical analyses that implicate mechanosensitive growth and remodeling processes. There is, therefore, a pressing need to quantify regional multiaxial wall stresses which, because of the membrane-like behavior of many aneurysms, necessitates better information on the applied loads and regional surface curvatures. Herein, we present and illustrate a method whereby regional curvatures can be estimated easily for sub-classes of human aneurysms based on clinically available data from magnetic resonance angiography (MRA). Whereas Legendre polynomials are used to illustrate this approach, different functions may prove useful for different sub-classes of lesions.

Transgenic overexpression of neuromedin U promotes leanness and hypophagia in mice

Recent work has shown that neuromedin U (NmU), a peptide initially identified as a smooth muscle contractor, may play a role in regulating food intake and energy homeostasis. To further evaluate this putative function, we measured food intake, body weight, energy expenditure and glucose homeostasis in transgenic mice that ubiquitously overexpress murine proNmU. NmU transgenic mice were lighter and had less somatic and liver fat, were hypophagic, and had improved insulin sensitivity as judged by an intraperitoneal insulin tolerance test. Transgenic mice had higher levels of hypothalamic NPY, POMC and MCH mRNA. There was no difference in O2 consumption between genotypes; however, NmU transgenic mice displayed a modest increase in respiratory quotient during food deprivation and refeeding. There were no behavioral disturbances in the NmU transgenic mice that could account for the results (e.g. changes in locomotor activity). When placed on a high-fat diet, transgenic mice remained lighter than wild-type mice and ate less, but gained weight at a rate similar to wild-type mice. Despite the increased weight gain with high-fat feeding, glucose tolerance was significantly improved in the transgenic mice. These findings support the hypothesized role of NmU as an endogenous anorexigenic peptide.

Variegated micelle surfaces: correlating the microstructure of mixed surfactant micelles with bulk solution properties

Electron paramagnetic resonance, viscosity, and small-angle neutron scattering (SANS) measurements have been used to study the interaction of mixed anionic/nonionic surfactant micelles with the polyampholytic protein gelatin. Sodium dodecyl sulfate (SDS) and the nonionic surfactant dodecylmalono-bis-N-methylglucamide (C12BNMG) were chosen as "interacting" and "noninteracting" surfactants, respectively; SDS micelles bind strongly to gelatin but C12BNMG micelles do not. Further, the two surfactants interact synergistically in the absence of the gelatin. The effects of total surfactant concentration and surfactant mole fraction have been investigated. Previous work (Griffiths et al. Langmuir 2000, 16 (26), 9983-9990) has shown that above a critical solution mole fraction, mixed micelles bind to gelatin. This critical mole fraction corresponds to a micelle surface that has no displaceable water (Griffiths et al. J. Phys. Chem. B 2001, 105 (31), 7465). On binding of the mixed micelle, the bulk solution viscosity increases, with the viscosity-surfactant concentration behavior being strongly dependent on the solution surfactant mole fraction. The viscosity at a stoichiometry of approximately one micelle per gelatin molecule observed in SDS-rich mixtures scales with the surface area of the micelle occupied by the interacting surfactant, SDS. Below the critical solution mole fraction, there is no significant increase in viscosity with increasing surfactant concentration. Further, the SANS behavior of the gelatin/mixed surfactant systems below the critical micelle mole fraction can be described as a simple summation of those arising from the separate gelatin and binary mixed surfactant micelles. By contrast, for systems above the critical micelle mole fraction, the SANS data cannot be described by such a simple approach. No signature from any unperturbed gelatin could be detected in the gelatin/mixed surfactant system. The gelatin scattering is very similar in form to the surfactant scattering, confirming the widely accepted picture that the polymer "wraps" around the micelle surface. The gelatin scattering in the presence of deuterated surfactants is insensitive to the micelle composition provided the composition is above the critical value, suggesting that the viscosity enhancement observed arises from the number and strength of the micelle-polymer contact points rather than the gelatin conformation per se.

Bicycle helmet campaigns and head injuries among children. Does poverty matter?

OBJECTIVES

To assess the impact of a community based bicycle helmet programme aimed at children aged 5-12 years (about 140,000) from poor and well off municipalities.

METHODS

A quasi-experimental design, including a control group, was used. Changes in the risk of bicycle related head injuries leading to hospitalisation were measured, using rates ratios.

RESULTS

Reductions in bicycle related head injuries were registered in both categories of municipalities. Compared with the pre-programme period, the protective effect of the programme during the post-programme period was as significant among children from poor municipalities (RR= 0.45 95%CI 0.26 to 0.78) as among those from richer municipalities (RR=0.55 95%CI 0.41 to 0.75).

CONCLUSION

Population based educational programmes may have a favourable impact on injury risks in poor areas despite lower adoption of protective behaviours.

Ezetimibe selectively inhibits intestinal cholesterol absorption in rodents in the presence and absence of exocrine pancreatic function

1. Ezetimibe potently inhibits the transport of cholesterol across the intestinal wall, thereby reducing plasma cholesterol in preclinical animal models of hypercholesterolemia. The effect of ezetimibe on known absorptive processes was determined in the present studies. 2. Experiments were conducted in the hamster and/or rat to determine whether ezetimibe would affect the absorption of molecules other than free cholesterol, namely cholesteryl ester, triglyceride, ethinylestradiol, progesterone, vitamins A and D, and taurocholic acid. In addition, to determine whether exocrine pancreatic function is involved in the mechanism of action of ezetimibe, a biliary anastomosis model, which eliminates exocrine pancreatic function from the intestine while maintaining bile flow, was established in the rat. 3. Ezetimibe reduced plasma cholesterol and hepatic cholesterol accumulation in cholesterol-fed hamsters with an ED(50) of 0.04 mg kg(-1). Utilizing cholesteryl esters labelled on either the cholesterol or the fatty acid moiety, we demonstrated that ezetimibe did not affect cholesteryl ester hydrolysis and the absorption of fatty acid thus generated in both hamsters and rats. The free cholesterol from this hydrolysis, however, was not absorbed (92 - 96% inhibition) in the presence of ezetimibe. Eliminating pancreatic function in rats abolished hydrolysis of cholesteryl esters, but did not affect the ability of ezetimibe to block absorption of free cholesterol (-94%). Ezetimibe did not affect the absorption of triglyceride, ethinylestradiol, progesterone, vitamins A and D, and taurocholic acid in rats. 4. Ezetimibe is a potent inhibitor of intestinal free cholesterol absorption that does not require exocrine pancreatic function for activity. Ezetimibe does not affect the absorption of triglyceride as a pancreatic lipase inhibitor (Orlistat) would, nor does it affect the absorption of vitamin A, D or taurocholate, as a bile acid sequestrant (cholestyramine) would.

Ezetimibe, a potent cholesterol absorption inhibitor, normalizes combined dyslipidemia in obese hyperinsulinemic hamsters

Ezetimibe potently and selectively inhibits cholesterol absorption in the intestine, thereby reducing plasma cholesterol in preclinical models of hypercholesterolemia. Clinical trials have demonstrated that ezetimibe lowers LDL cholesterol and raises HDL cholesterol in humans. The effect of ezetimibe on other dyslipidemias, particularly hypertriglyceridemia, is not yet known. In the present studies, we assessed the effect of ezetimibe on combined hypercholesterolemia and hypertriglyceridemia in obese hyperinsulinemic hamsters. Hamsters were fed chow, chow with cholesterol (0.12%), or the same cholesterol diet containing different dietary triglycerides (15%) in the absence or presence of 1 mg/kg ezetimibe (in diet) for up to 84 days. Body weight, serum insulin, leptin, glucose, cholesterol, and triglyceride levels were analyzed. Cholesterol and triglyceride levels were also determined in VLDL+IDL, LDL, and HDL. Hamsters maintained on high-fat diets became obese, hyperinsulinemic, hyperleptinemic, hypercholesterolemic, and hypertriglyceridemic. Ezetimibe did not affect body weight, insulin, or leptin, but ablated the combined hypercholesterolemia and hypertriglyceridemia induced by high-fat diets. Ezetimibe normalized VLDL+IDL cholesterol and triglyceride and significantly decreased LDL cholesterol to below chow-fed levels. The ratio of HDL to LDL cholesterol increased significantly with the addition of ezetimibe. Ezetimibe completely eliminated the accumulation of cholesteryl ester and free cholesterol in liver that was induced under the various dietary conditions in the absence of drug. In conclusion, ezetimibe is very effective in correcting the combined dyslipidemia in diet-induced obese hyperinsulinemic hamsters and may be an effective therapy for ameliorating combined dyslipidemia in obese insulin-resistant and/or type 2 diabetic humans.

Comparison of the activity and disposition of the novel cholesterol absorption inhibitor, SCH58235, and its glucuronide, SCH60663

Previous studies described the metabolism-based discovery of a potent, selective inhibitor of intestinal absorption of cholesterol, SCH58235 (Ezetimibe). Here we demonstrate that the phenolic glucuronide (SCH60663) of SCH58235, was more potent at inhibiting cholesterol absorption in rats than SCH58235, when administered by the intraduodenal route. To understand the increased potency of the glucuronide, the metabolism and distribution of SCH58235 and SCH60663 were studied in bile duct-cannulated rats. One minute after intraduodenal delivery of SCH58235, significant levels of compound were detected in portal plasma; >95% was glucuronidated, indicating that the intestine was metabolizing SCH58235 to its glucuronide. When intraduodenally delivered as SCH58235, the compound was glucuronidated, moved through the intestinal wall, into portal plasma, through the liver, and into bile. However, when delivered as SCH60663, >95% of the compound remained in the intestinal lumen and wall, which may explain its increased potency. Significant inhibition of cholesterol absorption and glucuronidation of SCH58235 occurred when SCH58235 was intravenously injected into bile duct-cannulated rats. Autoradiographic analysis demonstrated that drug related material was located throughout the intestinal villi, but concentrated in the villus tip. These data indicate that (a) SCH58235 is rapidly metabolized in the intestine to its glucuronide; (b) once glucuronidated, the dose is excreted in the bile, thereby delivering drug related material back to the site of action and (c) the glucuronide is more potent than the parent possibly because it localizes to the intestine. Taken together, these data may explain the potency of SCH58235 in the rat (ID(50) = 0.0015 mg kg(-1)) and rhesus monkey (ID(50) = 0.0005 mg kg(-1)).

Evaluation of a four-year bicycle helmet promotion campaign in Quebec aimed at children ages 8 to 12: impact on attitudes, norms and behaviours

OBJECTIVE

This study evaluated a four-year bicycle helmet promotion campaign.

METHODS

Children's attitudes, social norms, intentions to wear a bicycle helmet as well as helmet ownership were measured. Evaluation was based on a pre-experimental static group comparison design repeated at two (1991) and four years (1993) after implantation, with a non-randomized control group. 3,424 students completed a self-administered questionnaire (experimental: 2,097, control: 1,327).

RESULTS

The program had a significant impact on helmet ownership (1989: 4%; 1991: 26%; 1993: 56%). The program was the principal predictor of high intention to use a bicycle helmet. Time was the principal predictor of ownership with exposure to the program being the next predictor.

CONCLUSION

This study showed that time is an important factor in bicycle helmet acquisition, and that a long-term community-based program can accelerate the process of adopting this behaviour.

Efficiency of uphill locomotion in nocturnal and diurnal lizards

Nocturnal geckos can walk on level ground more economically than diurnal lizards. One hypothesis for why nocturnal geckos have a low cost of locomotion is that they can perform mechanical work during locomotion more efficiently than other lizards. To test this hypothesis, we compared the efficiency of the nocturnal gecko Coleonyx variegatus (average body mass 4.2 g) and the diurnal skink Eumeces skiltonianus (average body mass 4.8 g) when they performed vertical work during uphill locomotion. We measured the rate of oxygen consumption when each species walked on the level and up a 50 slope over a range of speeds. For Coleonyx variegatus, the energetic cost of traveling a unit distance (the minimum cost of transport, Cmin) increased from 1.5 to 2.7 ml O2 kg-1 m-1 between level and uphill locomotion. For Eumeces skiltonianus, Cmin increased from 2.5 to 4.7 ml O2 kg-1 m-1 between level and uphill locomotion. By taking the difference between Cmin for level and uphill locomotion, we found that the efficiency of performing vertical work during locomotion was 37 % for Coleonyx variegatus and 19 % for Eumeces skiltonianus. The similarity between the 1.9-fold difference in vertical efficiency and the 1.7-fold difference in the cost of transport on level ground is consistent with the hypothesis that nocturnal geckos have a lower cost of locomotion than other lizards because they can perform mechanical work during locomotion more efficiently.

The effects of a 4-year program promoting bicycle helmet use among children in Quebec

OBJECTIVES

This study assessed the effectiveness of a 4-year program of bicycle helmet promotion that targeted elementary school children in one region of Quebec. The program revolved primarily around persuasive communication and community organization, combining standard educational activities and activities to facilitate helmet acquisition and use.

METHODS

Helmet use was compared between more than 8000 young cyclists in municipalities exposed or not exposed to the program. Factors influencing helmet use were controlled through the use of multivariate analyses.

RESULTS

Helmet use increased from 1.3% before program implementation to 33% in 1993. The program was clearly effective in most cycling circumstances and for various groups of children. However, the benefits of the program were unequally distributed; the program was one third as effective in poorer municipalities as in "average-rich" ones.

CONCLUSIONS

This community-based program that combined various types of activities appeared to be effective. New intervention models are needed to ensure an equitable distribution of benefits.

Mode of action of bullatacin, a potent antitumor acetogenin: inhibition of NADH oxidase activity of HeLa and HL-60, but not liver, plasma membranes

Bullatacin, a potential antitumor substance isolated from plants of the Annonaceae, and analogs of bullatacin, known collectively as acetogenins, have been reported previously to show potent activity in the inhibition of growth of murine tumors and human tumor xenografts grown in athymic mice as well as an ability to inhibit mitochondrial electron transport. In this report, we show activity of bullatacin in inhibition of NADH oxidase activity of plasma membrane vesicles isolated from HeLa cells and HL-60 cells but not with plasma membrane vesicles isolated from rat livers which, unlike the inhibition of mitochondrial activity, correlated with the ability of the acetogenins to kill tumor cells. Additionally, bullatacin is active against HL-60 cells that are resistant to adriamycin which may suggest utility for bullatacin in management of drug-resistant cells and cell lines.

Predicting and reinforcing children's intentions to wear protective helmets while bicycling

The researchers undertook to identify the factors that are most likely to influence children's intentions to use bicycle helmets. To determine the most important intention influencing factors, a random sample of 797 students in grades 4 through 6 completed a self-administered questionnaire concerning their beliefs about helmet use. They were asked about their perceptions of the risk of riding bicycles unprotected, the severity of possible head injuries, and about other bicycle-safety related behaviors. Factors that best predicted the student's intentions to use bicycle helmets involved both behavioral beliefs and normative beliefs. Analysis of factors influencing those with low intentions to use helmets, compared to those with high intentions, suggests the most effective messages that health planners can provide preadolescents to influence them to use helmets. They are that helmet use is fun and attractive, helmets provide a new look and a sporting image, and friends approve of and value this behavior. Parents, and particularly mothers, can reinforce their children's intentions to use helmets and their involvement should be encouraged.

Evidence for distinct systemic extravasation effects of platelet activating factor, leukotrienes B4, C4, D4 and histamine in the guinea pig

The relative potencies of platelet-activating factor (PAF), leukotrienes B4 (LTB4), C4 (LTC4), D4 (LTD4) and histamine to induce hemoconcentration (HC) were evaluated in the guinea pig. The maximal hematocrit increase (MHI) from PAF, LTD4 and histamine occurred 5-7 min after i.v. injection, whereas the MHI of LTC4 occurred 13-15 min after injection. LTB4 (2.97-5.95 nmol kg-1) did not produce HC. The magnitude of PAF-induced MHI was 2-fold that of LTC4 or LTD4, regardless of the dose of leukotrienes used. The doses (nmol kg-1) needed to produce 30% HC were: 0.14-PAF, 0.71-LTD4 and 3.37-LTC4 and 2,400 histamine. The HC effects of LTD4 were markedly reduced by prior administration of FPL-55712. However, neither LTC4 or LTD4 HC effects were significantly reduced by prior i.v. injection of CV-3988 (3.4 mg kg-1), a competitive receptor antagonist to PAF which is 98% effective in abolishing HC response to 0.14 nmol kg-1 PAF. Diphenhydramine abolished histamine-induced hemoconcentration but was without effect on PAF or LTD4. These results suggest that the responses of PAF, leukotrienes and histamine differ in their potency and may involve separate vascular recognition sites related to acute increases in vascular permeability.