Sphingosine 1-phosphate (S1P) is a bioactive lysolipid with pleiotropic functions mediated through a family of G proteincoupled receptors, S1P 1,2,3,4,5 . Physiological effects of S1P receptor agonists include regulation of cardiovascular function and immunosuppression via redistribution of lymphocytes from blood to secondary lymphoid organs. The phosphorylated metabolite of the immunosuppressant agent FTY720 (2-amino-2-(2-[4-octylphenyl]ethyl)-1,3-propanediol) and other phosphonate analogs with differential receptor selectivity were investigated. No significant species differences in compound potency or rank order of activity on receptors cloned from human, murine, and rat sources were observed. All synthetic analogs were high-affinity agonists on S1P 1 , with IC 50 values for ligand binding between 0.3 and 14 nM. The correlation between S1P 1 receptor activation and the ED 50 for lymphocyte reduction was highly significant (p Ͻ 0.001) and lower for the other receptors. In contrast to S1P 1 -mediated effects on lymphocyte recirculation, three lines of evidence link S1P 3 receptor activity with acute toxicity and cardiovascular regulation: compound potency on S1P 3 correlated with toxicity and bradycardia; the shift in potency of phosphorylated-FTY720 for inducing lymphopenia versus bradycardia and hypertension was consistent with affinity for S1P 1 relative to S1P 3 ; and toxicity, bradycardia, and hypertension were absent in S1P 3 Ϫ/Ϫ mice. Blood pressure effects of agonists in anesthetized rats were complex, whereas hypertension was the predominant effect in conscious rats and mice. Immunolocalization of S1P 3 in rodent heart revealed abundant expression on myocytes and perivascular smooth muscle cells consistent with regulation of bradycardia and hypertension, whereas S1P 1 expression was restricted to the vascular endothelium.
Background and purpose: Inhibition of cholesteryl ester transfer protein (CETP) with torcetrapib in humans increases plasma high density lipoprotein (HDL) cholesterol levels but is associated with increased blood pressure. In a phase 3 clinical study, evaluating the effects of torcetrapib in atherosclerosis, there was an excess of deaths and adverse cardiovascular events in patients taking torcetrapib. The studies reported herein sought to evaluate off-target effects of torcetrapib. Experimental approach: Cardiovascular effects of the CETP inhibitors torcetrapib and anacetrapib were evaluated in animal models. Key results: Torcetrapib evoked an acute increase in blood pressure in all species evaluated whereas no increase was observed with anacetrapib. The pressor effect of torcetrapib was not diminished in the presence of adrenoceptor, angiotensin II or endothelin receptor antagonists. Torcetrapib did not have a contractile effect on vascular smooth muscle suggesting its effects in vivo are via the release of a secondary mediator. Treatment with torcetrapib was associated with an increase in plasma levels of aldosterone and corticosterone and, in vitro, was shown to release aldosterone from adrenocortical cells. Increased adrenal steroid levels were not observed with anacetrapib. Inhibition of adrenal steroid synthesis did not inhibit the pressor response to torcetrapib whereas adrenalectomy prevented the ability of torcetrapib to increase blood pressure in rats. Conclusions and implications: Torcetrapib evoked an acute increase in blood pressure and an acute increase in plasma adrenal steroids. The acute pressor response to torcetrapib was not mediated by adrenal steroids but was dependent on intact adrenal glands.
Large studies on bedaquiline used to treat multidrug-resistant (MDR-) and extensively drug-resistant tuberculosis (XDR-TB) are lacking. This study aimed to evaluate the safety and effectiveness of bedaquiline-containing regimens in a large, retrospective, observational study conducted in 25 centres and 15 countries in five continents.428 culture-confirmed MDR-TB cases were analysed (61.5% male; 22.1% HIV-positive, 45.6% XDR-TB). MDR-TB cases were admitted to hospital for a median (interquartile range (IQR)) 179 (92-280) days and exposed to bedaquiline for 168 (86-180) days. Treatment regimens included, among others, linezolid, moxifloxacin, clofazimine and carbapenems (82.0%, 58.4%, 52.6% and 15.3% of cases, respectively).Sputum smear and culture conversion rates in MDR-TB cases were 63.6% and 30.1%, respectively at 30 days, 81.1% and 56.7%, respectively at 60 days; 85.5% and 80.5%, respectively at 90 days and 88.7% and 91.2%, respectively at the end of treatment. The median (IQR) time to smear and culture conversion was 34 (30-60) days and 60 (33-90) days. Out of 247 culture-confirmed MDR-TB cases completing treatment, 71.3% achieved success (62.4% cured; 8.9% completed treatment), 13.4% died, 7.3% defaulted and 7.7% failed. Bedaquiline was interrupted due to adverse events in 5.8% of cases. A single case died, having electrocardiographic abnormalities that were probably non-bedaquiline related.Bedaquiline-containing regimens achieved high conversion and success rates under different nonexperimental conditions.
The worldwide increase in the incidence of diabetes, the increase in type 2 diabetes in women at reproductive ages, and the cross-generation of the intrauterine programming of type 2 diabetes are the bases for the growing interest in the use of experimental diabetic models in order to gain insight into the mechanisms of induction of developmental alterations in maternal diabetes. In this scenario, experimental models that present the most common features of diabetes in pregnancy are highly required. Several important aspects of human diabetic pregnancies such as the increased rates of spontaneous abortions, malformations, fetoplacental impairments, and offspring diseases in later life can be approached by using the appropriate animal models. The purpose of this review is to give a practical and critical guide into the most frequently used experimental models in diabetes and pregnancy, discuss their advantages and limitations, and describe the aspects of diabetes and pregnancy for which these models are thought to be adequate. This review provides a comprehensive view and an extensive analysis of the different models and phenotypes addressed in diabetic animals throughout pregnancy. The review includes an analysis of the surgical, chemical-induced, and genetic experimental models of diabetes and an evaluation of their use to analyze early pregnancy defects, induction of congenital malformations, placental and fetal alterations, and the intrauterine programming of metabolic diseases in the offspring's later life.
Vaccination can play a useful role in mastitis control programs, although there is a relative dearth of large, well-controlled field efficacy studies. This paper presents the findings on the use of a commercially available vaccine (Startvac, Hipra UK Ltd., Nottingham, UK) on commercial units under UK field conditions. In total, 3,130 cows were recruited from 7 farms and were randomly allocated, within farm, to 1 of 3 groups. The first group received the vaccine following the label regimen, the second group was vaccinated every 90 d following an initial vaccination course, and the third group was left unvaccinated to act as controls. Vaccine efficacy was assessed in the first 120 d of lactation. Data were available for analysis from 1,696 lactations in 1,549 cows. In total, 779 cases of clinical mastitis occurred in the 3 study groups, and we detected no significant difference in the incidence or prevalence of clinical or subclinical mastitis between any of the 3 groups. Mastitis vaccination following the label regimen was associated with a significant reduction in the severity of clinical cases. Cows in this group were at significantly decreased odds of developing clinical mastitis presenting with more than just milk changes [odds ratio: 0.58; 95% confidence interval (CI): 0.35-0.98]. Similarly, each additional vaccination resulted in a cow being at decreased odds of developing clinical mastitis presenting with more than just milk changes (odds ratio: 0.87; 95% CI: 0.77-0.98). Although no cows were culled because of severe mastitis in either of the vaccinated groups, we detected no significant difference in the mastitis-related culling rate between groups. Analysis of milk production data demonstrated that, on average, cows on the label regimen produced a higher volume of milk (231 L; 95% CI: 104.1-357.4) and more milk solids (12.36 kg; 95% CI: 3.12-21.60) than unvaccinated cows in the first 120 d of lactation. Conservative analysis suggested that a return on investment of 2.57:1 could be expected under UK conditions based on increased milk yield alone.
No large study has ever evaluated the efficacy, safety and tolerability of meropenem/ clavulanate to treat multidrug-and extensively drug-resistant tuberculosis (MDR-and XDR-TB). The aim of this observational study was to evaluate the therapeutic contribution, effectiveness, safety and tolerability profile of meropenem/clavulanate added to a background regimen when treating MDR-and XDR-TB cases.Patients treated with a meropenem/clavulanate-containing regimen (n=96) showed a greater drug resistance profile than those exposed to a meropenem/clavulanate-sparing regimen (n=168): in the former group XDR-TB was more frequent (49% versus 6.0%, p<0.0001) and the median (interquartile range (IQR)) number of antibiotic resistances was higher (8 (6-9) versus 5 (4-6)). Patients were treated with a meropenem/clavulanate-containing regimen for a median (IQR) of 85 (49-156) days.No statistically significant differences were observed in the overall MDR-TB cohort and in the subgroups with and without the XDR-TB patients; in particular, sputum smear and culture conversion rates were similar in XDR-TB patients exposed to meropenem/clavulanate-containing regimens (88.0% versus 100.0%, p=1.00 and 88.0% versus 100.0%, p=1.00, respectively). Only six cases reported adverse events attributable to meropenem/clavulanate (four of them then restarting treatment).The nondifferent outcomes and bacteriological conversion rate observed in cases who were more severe than controls might imply that meropenem/clavulanate could be active in treating MDR-and XDR-TB cases. @ERSpublications Meropenem/clavulanate is effective and safe to treat MDR-and XDR-TB in comparison with controls
Maternal diabetes increases the risk of congenital malformations, placental dysfunction and diseases in both the neonate and the offspring's later life. Oxidative stress has been involved in the etiology of these abnormalities. Matrix metalloproteases (MMPs), involved in multiple developmental pathways, are increased in the fetus and placenta from diabetic experimental models. As oxidants could be involved in the activation of latent MMPs, we investigated a putative relationship between MMPs activities and oxidative stress in the feto-placental unit of diabetic rats at midgestation. We found that H2O2 enhanced and that superoxide dismutase (SOD) reduced MMPs activities in the maternal side of the placenta and in the fetuses from control and diabetic rats. MMPs were not modified by oxidative status in the fetal side of the placenta. Lipid peroxidation was enhanced in the maternal and fetal sides of the placenta and in the fetus from diabetic rats when compared to controls, and gradually decreased from the maternal placental side to the fetus in diabetic animals. The activities of the antioxidant enzymes SOD and catalase were decreased in the maternal placental side, catalase activity was enhanced in the fetal placental side and both enzymes were increased in the fetuses from diabetic rats when compared to controls. Our data demonstrate changes in the oxidative balance and capability of oxidants to upregulate MMPs activity in the feto-placental unit from diabetic rats, a basis to elucidate links between oxidative stress and alterations in the developmental pathways in which MMPs are involved.
Background-Multidrug resistant tuberculosis (MDR TB) requires a complex drug regimen and lengthy multidisciplinary care. The financial cost of successful management of each case is potentially large. Methods-The costs of managing nine HIV negative patients with pulmonary MDR TB were compared with 18 age group and ethnicity matched controls with fully sensitive disease. Calculations included: cost of outpatient visits and inpatient stays including negative pressure isolation; costs of drug provision and toxicity monitoring; costs of additional procedures and multidisciplinary referrals. Results-The mean cost of managing a case of pulmonary MDR TB was in excess of £60 000 and for sensitive disease it was £6040. Conclusions-Clinicians and healthcare commissioning authorities may both be underestimating the costs of managing MDR TB, and accordingly the consequences for units dealing with such cases may be serious. Funding of care for MDR TB in the UK requires strategic decisions at regional or governmental level. (Thorax 2000;55:962-963)
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