Lesion Orientation of O4-Alkylthymidine Influences Replication by Human DNA Polymerase η.

DNA lesions that elude repair may undergo translesion synthesis catalyzed by Y-family DNA polymerases. O4-Alkylthymidines, persistent adducts that can result from carcinogenic agents, may be encountered by DNA polymerases. The influence of lesion orientation around the C4-O4 bond on processing by human DNA polymerase η (hPol η) was studied for oligonucleotides containing O4-methylthymidine, O4-ethylthymidine, and analogs restricting the O4-methylene group in an anti-orientation. Primer extension assays revealed that the O4-alkyl orientation influences hPol η bypass. Crystal structures of hPol η•DNA•dNTP ternary complexes with O4-methyl- or O4-ethylthymidine in the template strand showed the nucleobase of the former lodged near the ceiling of the active site, with the syn-O4-methyl group engaged in extensive hydrophobic interactions. This unique arrangement for O4-methylthymidine with hPol η, inaccessible for the other analogs due to steric/conformational restriction, is consistent with differences observed for nucleotide incorporation and supports the concept that lesion conformation influences extension across DNA damage. Together, these results provide mechanistic insights on the mutagenicity of O4MedT and O4EtdT when acted upon by hPol η.

Considerations in the Evaluation of Potential Efficacy of Medications for Alcohol and Drug Use Disorders: An Editorial.

The societal burden created by alcohol and drug use disorders is estimated to be on the order of hundreds of billions of dollars, creating a need for effective medications to reduce use and prevent relapse. While there are FDA-approved medications to facilitate abstinence and prevent relapse for some indications including, alcohol, tobacco, and opiate use disorders, there are no approved treatments for other abused substances, including cocaine, methamphetamine, and cannabis, leaving these critical medical needs unmet. The development of such medications has fallen largely to the government with efforts spearheaded by the National Institute on Drug Abuse and the National Institute on Alcoholism and Alcohol Abuse. Both agencies have medication development programs with preclinical components that include the standardized evaluation of compounds using animal models. This chapter describes the rationale and considerations involved in the use of such models, including reinstatement of drug self-administration.

The glucagon-like peptide-1 receptor as a potential treatment target in alcohol use disorder: evidence from human genetic association studies and a mouse model of alcohol dependence.

The hormone glucagon-like peptide-1 (GLP-1) regulates appetite and food intake. GLP-1 receptor (GLP-1R) activation also attenuates the reinforcing properties of alcohol in rodents. The present translational study is based on four human genetic association studies and one preclinical study providing data that support the hypothesis that GLP-1R may have a role in the pathophysiology of alcohol use disorder (AUD). Case-control analysis (N = 908) was performed on a sample of individuals enrolled in the National Institute on Alcohol Abuse and Alcoholism (NIAAA) intramural research program. The Study of Addiction: Genetics and Environment (SAGE) sample (N = 3803) was used for confirmation purposes. Post hoc analyses were carried out on data from a human laboratory study of intravenous alcohol self-administration (IV-ASA; N = 81) in social drinkers and from a functional magnetic resonance imaging study in alcohol-dependent individuals (N = 22) subjected to a Monetary Incentive Delay task. In the preclinical study, a GLP-1R agonist was evaluated in a mouse model of alcohol dependence to demonstrate the role of GLP-1R for alcohol consumption. The previously reported functional allele 168Ser (rs6923761) was nominally associated with AUD (P = 0.004) in the NIAAA sample, which was partially replicated in males of the SAGE sample (P = 0.033). The 168 Ser/Ser genotype was further associated with increased alcohol administration and breath alcohol measures in the IV-ASA experiment and with higher BOLD response in the right globus pallidus when receiving notification of outcome for high monetary reward. Finally, GLP-1R agonism significantly reduced alcohol consumption in a mouse model of alcohol dependence. These convergent findings suggest that the GLP-1R may be an attractive target for personalized pharmacotherapy treatment of AUD.

[Management of the diabetic foot: which criteria for clinical evaluation and initial management?]. / Pied diabetique a risque: quels reperes pour l'evaluation clinique et la prise en charge initiale.

The diabetic foot remains a diabetes complication with potentially devastating consequences, which is initially silent and too often neglected. Its systematic screening first has to target the estimation of the risk level of foot lesions. This estimation is based on clinical examination regarding the severity of neuropathy, its consequences and of a possibly associated arterial disease. Preventive interventions are determined according to the risk level. They always rely on an important involvement of the patient, which in turn requires the healthcare professionals' engagement in individualized patient education and psychosocial support. Wound management and its diagnostic and therapeutic challenges usually calls for a collaborative approach involving several different specialists.

An intravenous insulin protocol for strict glycemic control in acute ischaemic stroke.

BACKGROUND AND PURPOSE: There is a J-shaped association between admission glycemia and outcome. We designed an intravenous insulin protocol aiming at rapid and strict glucose control in hyperglycemic ischaemic stroke patients. Here, we describe the initial experience, safety, and efficacy of this protocol to achieve and maintain euglycemia in the first 48h. METHODS: The protocol is based on parallel scales for adjustment of insulin infusion rate according to current glycemia and the rate of change of glycemia, which was recommended in our stroke unit in 4/2007 in acute ischaemic stroke patients with glycemia >6mM. Data were registered in the Acute Stroke Registry and Analysis of Lausanne (ASTRAL). Capillary blood glycemia was measured hourly with fingerprick test at onset of treatment and after each scale change. Target glycemia was 4.0-6.0mM pre-prandially (5.5-8.0mM post-prandially). Hypokalemia was defined as serum potassium <3.5mM and measured every 12h. Specific algorithms were employed during meals and for patients leaving temporarily the stroke unit for diagnostic or therapeutic workup. RESULTS: In the 90 protocol patients, the first normoglycemia was achieved within 8h of treatment in 91.1% of patients (median interval 4h (interquartile range (IQR): 3-6). During the median treatment duration of 25.5h (IQR: 19.7-37.7), median glucose reduction was 2.5mM (IQR: 1.3-4.3mM). The overall rate of hypoglycemias was 4.5% and hypokalemias 18.5%. There was a significant increase in the proportion of hypokalemias on the first on-treatment measurement compared to admission (24.4% vs. 8.9%, P=0.002). CONCLUSIONS: The proposed intravenous insulin protocol controls acute post-stroke hyperglycemia but frequently leads to hypokalemia. This issue needs to be addressed for the protocol to be suitable for use in larger, randomized controlled trial to explore its clinical effect.

Assessment of a new Goldmann applanation tonometer.

BACKGROUND/AIMS: The classic Goldmann applanation tonometer (GAT) has been further developed by Haag-Streit International. The applanation principle has been retained, while the internal force transmission and the pressure gauging have been optimised, the display of results digitised. The authors compared the GAT standard with the new GAT digital. METHODS: Four fixed tonometer pairs were used. The protocol included: non-contact pachymetry, slit-lamp examination, three consecutive measurements with each tonometer with a 5 min interval in between, check for side effects in 15 min. Three groups (intraocular pressure (IOP) levels) were defined: (1) IOP ≤ 16; (2) IOP>16 and <23; (3) IOP ≥ 23 mm Hg. RESULTS: 125 Patients (250 eyes) were evaluated. IOP (mm Hg), GAT standard versus GAT digital, for the rights eyes was: Group 1: 12.94 ± 0.55 versus 13.11 ± 0.53, p=0.71. Group 2: 18.26 ± 0.59 versus 18.03 ± 0.52, p=0.53; Group 3: 30.28 ± 0.48 versus 30.42 ± 0.41, p=0.97; all right eyes: 17.48 ± 7.48 versus 17.73 ± 7.4, p=0.99. For the left eyes, there was no significant difference, either. The correlation was very good and was not influenced by the IOP level. The Pearson coefficient for the right eye was 0.985, and for the left eye 0.994. In the Bland-Altman analysis, although there were two single readings that differed by as much as 5 mm Hg, GAT digital measures showed almost no skew, and the mean difference was 0.03 ± 1.23 mm Hg (n=250). A multiple regression analysis showed no influence of order of measurement, eyeside or pachymetry. CONCLUSIONS: The new GAT digital is as reliable and safe as GAT standard. IOP values correlate well. It offers a digitised display and a wireless transfer of data. The display of values up to the first decimal digit is not necessarily associated with a more precise measurement, but may offer an additional comfort compared with the 2 mm Hg scale of the classic GAT.

Persistent hyperglycemia at 24-48 h in acute hyperglycemic stroke patients is not associated with a worse functional outcome.

BACKGROUND: Recently, it was shown that the relation between admission glucose and functional outcome after ischemic stroke is described by a J-shaped curve, with a glucose range of 3.7-7.3 mmol/l associated with a favorable outcome. We tested the hypothesis that persistence of hyperglycemia above this threshold at 24-48 h after stroke onset impairs 3-month functional outcome. METHODS: We analyzed all patients with glucose >7.3 mmol/l on admission from the Acute STroke Registry and Analysis of Lausanne (ASTRAL). Patients were divided into two groups according to their subacute glucose level at 24-48 h after last well-being time (group 1: ≤7.3 mmol/l, group 2: >7.3 mmol/l). A favorable functional outcome was defined as a modified Rankin Score (mRS) ≤2 at 3 months. A multiple logistic regression analysis of multiple demographic, clinical, laboratory and neuroimaging covariates was performed to assess predictors of an unfavorable outcome. RESULTS: A total of 1,984 patients with ischemic stroke were admitted between January 1, 2003 and October 20, 2009, within 24 h after last well-being time. In the 421 patients (21.2%) with admission glucose >7.3 mmol/l, the proportion of patients with a favorable outcome was not statistically significantly different between the two groups (59.2 vs. 48.7%, respectively). In multiple logistic regression analysis, unfavorable outcome was significantly associated with age (odds ratio, OR: 1.06, 95% confidence interval, 95% CI: 1.03-1.08 for every 10-year increase), National Institute of Health Stroke Score, NIHSS score, on admission (OR: 1.16, 95% CI: 1.11-1.21), prehospital mRS (OR: 12.63, 95% CI: 2.61-61.10 for patients with score >0), antidiabetic drug usage (OR: 0.36, 95% CI: 0.15-0.86) and glucose on admission (OR: 1.16, 95% CI: 1.02-1.31 for every 1 mmol/l increase). No association was found between persistent hyperglycemia at 24-28 h and outcome in either diabetics or nondiabetics. CONCLUSIONS: In ischemic stroke patients with acute hyperglycemia, persistent hyperglycemia (>7.3 mmol/l) at 24-48 h after stroke onset is not associated with a worse functional outcome at 3 months whether the patient was previously diabetic or not.

Prolactin induces a hyperpolarising current in rat paraventricular oxytocinergic neurones.

Prolactin and oxytocin are important reproductive hormones implicated in several common adaptive functions during pregnancy, pseudopregnancy and lactation. Recently, extracellular recordings of supraoptic neurones have shown that prolactin may modulate the electrical activity of oxytocinergic neurones. However, no study has been conducted aiming to establish whether prolactin directly influences this activity in oxytocinergic paraventricular neurones. In the present study, we addressed this question by studying the effects of prolactin on the electrical activity and voltage-current relationship of identified paraventricular neurones in rat brain slices. Whole-cell recordings were obtained and neurones were classified on the basis of their morphological and electrophysiological fingerprint (i.e. magnocellular or parvicellular) and neuropeptide phenotype (i.e. oxytocinergic or non-oxytocinergic). We report that prolactin elicited a hyperpolarising current in 37% of the neurones in this nucleus, of which the majority (67%) were identified as putative magnocellular oxytocin neurones and the reminder (33%) were regarded as oxytocin-negative, parvicellular neuroendocrine neurones. Our results suggest that, in addition to the well-established negative feedback loop between prolactin-secreting lactotrophs and dopaminergic neurones in the arcuate nucleus, an inhibitory feedback loop also exists between lactotrophs and oxytocinergic paraventricular neurones.

[Transition from acute inpatient to chronic outpatient diabetes care: an symbolic situation]. / Transition entre hospitalisation aiguë et suivi ambulatoire chronique du patient diabétique: situation emblématique.

During an acute hospital stay, unpredictable glycemic changes related to the combined effects of multiple factors always ask for an increased attention to diabetes management. Initially an insulin treatment which has to be adjusted individually based on continuous glycemic follow-up is usually inevitable. This requires adequate coordination between the various health-care professionals who are simultaneously and successively involved in patient care. A proper discharge plan including reassessment of treatment, developed in consultation with the practicioners in charge of outpatient follow-up is a key component of this process. As in other complex conditions, deficiencies in this field are associated with increased errors and costs, which can be improved through interventions targeting inpatient to outpatient transition.

The effects of weightlessness on the human organism and mammalian cells.

It has always been a desire of mankind to conquest Space. A major step in realizing this dream was the completion of the International Space Station (ISS). Living there for several months confirmed early observations of short-term spaceflights that a loss of gravity affects the health of astronauts. Space medicine tries to understand the mechanism of microgravity-induced health problems and to conceive potent countermeasures. There are four different aspects which make space medicine appealing: i) finding better strategies for adapting astronauts to weightlessness; ii) identification of microgravity-induced diseases (e.g. osteoporosis, muscle atrophy, cardiac problems and others); iii) defining new therapies to conquer these diseases which will benefit astronauts as well as people on Earth in the end; and iv) on top of that, unveiling the mechanisms of weightlessness-dependent molecular and cellular changes is a requirement for improving space medicine. In mammalian cells, microgravity induces apoptosis and alters the cytoskeleton and affects signal transduction pathways, cell differentiation, growth, proliferation, migration and adhesion. This review focused on gravi-sensitive signal transduction elements and pathways as well as molecular mechanisms in human cells, aiming to understand the cellular changes in altered gravity. Moreover, the latest information on how these changes lead to clinically relevant health problems and current strategies of countermeasures are reviewed.

[Treatments for cardiovascular risk factors and screening for coronary artery disease in type 2 diabetes mellitus]. / Traitements des facteurs de risque cardiovasculaire et dépistage de la maladie coronarienne dans le diabète de type 2.

The recent ACCORD and DIAD studies revealed results which could modify treatments and the screening of diabetes vascular complications. Indeed, ACCORD shows no benefit on the prevention of diabetes vascular complications by aggressive treatment of hypertension or the combined treatment of the dyslipidemia. The intensive treatment of the blood glucose, if associated with severe hypoglycemias, increases mortality. DIAD revealed 20% of silent myocardial ischaemia in diabetic patients but no beneficial effect on the cardiovascular mortality. A careful reading of these studies in the light of long term studies such as UKPDS and STENO reveals that these negative results are generated by a too short follow-up and too aggressive objectives. The long term studies reveal that more realistic objectives remain beneficial.

[Diabetes]. / Diabète.

In 2009 a novel screening strategy for diabetes based on the level of glycated hemoglobin has been proposed by the main international organizations, with a diagnostic threshold of 6.5%. The preventive efficacy of multiple risk factor control in type 2 diabetes reflected by the low rate of cardiac events in the DIAD 2 study calls for a revision of the current recommendations for coronary disease screening. In gestational diabetes, the linear correlation between degree of hyperglycemia and risk of associated complications in the HAPO study strenghtens the therapeutic targets for this frequent condition, which identifies women at high future risk of diabetes. No conclusive evidence for an increased risk of cancer associated with insulin glargin remains when taking into account all the data currently available on this topic.

[The inefficacy of glycemic control in the hospitalized patient: origins and solutions]. / Inefficacité de la gestion de l'hyperglycémie du patient hospitalisé: origines et remèdes.

The hospital inpatient prevalence of diabetes mellitus can be estimated between 20 and 30%. Even moderate hyperglycemia is associated with increased morbidity and mortality in the acute care setting, whereas efficient glycemic control has been shown to improve both of them significantly. Glycemic control however remains largely inefficient outside of the intensive care unit due to the persistance of an inadequate glycemic management practice. We are currently developing a clinical care project aimed at changing this practice. For an efficient glycemic control, a training programme for health care professionals based on the concept of covering the insulin needs of the patient is mandatory. This programme needs to be integrated in a systemic approach, which takes the professionals' context in account.

[Trends in diabetes]. / Diabétologie.

A recent meta-analysis on the rosiglitazone in the treatment of type 2 diabetes revealed a significant increased risk of myocardial infarction and a trend to a higher cardiovascular mortality. In the following month after this publication, the methodology as its conclusions were criticized. This study shows the limits of the meta-analyses to which one lends a row obviously too high in the hierarchy of the levels of evidence. The study 4T evaluated 3 insulin strategies in the treatment of the type 2 diabetes. The results at one year show that only a minority of the patients achieve the goals. Post-Steno 2 was presented at the European congress diabetes. These new data confirm that the intensified treatment of all cardiovascular factors risk allows a major reduction of cardiovascular mortality after 13.3 years.

[What can be expected from the GLP-1 agonists and DPP-4 inhibitors in the treatment of type 2 diabetes?]. / Traitement du diabète de type 2: qu'attendre des analogues du GLP-1 et inhibiteurs de la DPP-4?

The GLP-1 agonists and DPP-4 inhibitors are two novel drug classes in the treatment of type 2 diabetes. They increase insulin secretion and inhibit glucagon secretion without risk of hypoglycaemia. A decrease of glycated haemoglobin of about 1% can be expected with their use as monotherapy and as add-on therapy to the usual oral antidiabetics. In addition, GLP-1 agonists induce weight reduction at the price of gastro-intestinal side-effects and the need for subcutaneous administration. DPP-4 inhibitors can be taken orally, are well-tolerated, but weight-neutral. In the absence of relevant clinical studies, their long-term efficacy is currently unknown, as well as the clinical impact of other promising effects like beta-cell preservation.

[Oral antidiabetic agents: which role in 2006?]. / Les antidiabétiques oraux: quelle place en 2006?

This article offers a review of the five classes of oral antidiabetics which are currently available, and focuses on practical considerations about the daily use of these drugs. Based on data from recent studies, it addresses several frequently asked questions. Which treatment to choose for which patient? How to adapt the treatment facing the progression of type 2 diabetes, which most often necessitates an intensification of the therapeutic means over time? Usually there are several initial therapeutic options for a given patient. The glycemic control over the following months allows to verify the efficiency of the treatment chosen. In case of a persistant glycemic imbalance, early intensification of the treatment is recommended.

[The Polypill: between myths and reality in the treatment of type 2 diabetes mellitus]. / La polypill: entre mythes et réalité dans le traitement du diabète sucré.

The Polypill: between myths and reality in the treatment of type 2 diabetes mellitus The concept of "Polypill" was developed from modeling analyses and the data were extracted from randomized-control trials and epidemiological studies. This "Polypill" should be a combination of three antihypertensive drugs associated to aspirin, a statin and folic acid. This "Polypill" would allow to reduce of more than 80% the cardiovascular events. The original publication suggests that all subjects of more than 55 years could benefit from this magic pill. Numerous positive and negative reactions showed themselves further to this publication. Other approaches based on the change of lifestyle seem so effective. Nevertheless, to have a really effective approach the therapeutic educational dimension should be also included in the basic strategy.

[Will the theory of metabolic memory change our therapeutic strategies in the face of type 2 diabetes?]. / La théorie de la mémoire métabolique: remet-elle en question notre stratégie thérapeutique face au diabète de type 2?

Many prospective studies have shown that tight glucose control reduces the risk of vascular complications in type 1 and type 2 diabetes. Besides, the intensive treatment group benefited from a preventive effect several years after the end of the study. In type 2 diabetes, the low glucose levels at the time of the diagnosis strongly correlate to the risk reduction of late complications. These various elements suggest the presence of a metabolic memory which would engage in very premature stages various pathways favoring the vascular development of diabetic complications. Our therapeutic strategy, based on thresholds of intervention favors the therapeutic slowness and strengthens negatively the metabolic memory. Therapeutic approach based on the tendencies to hyperglycemia could improve the prevention of the diabetic vascular complications.

High altitude impairs nasal transepithelial sodium transport in HAPE-prone subjects.

High-altitude pulmonary oedema (HAPE) occurs in predisposed individuals at altitudes >2,500 m. Defective alveolar fluid clearance secondary to a constitutive impairment of the respiratory transepithelial sodium transport contributes to its pathogenesis. Hypoxia impairs the transepithelial sodium transport in alveolar epithelial type II cells in vitro. If this impairment is also present in vivo, high-altitude exposure could aggravate the constitutive defect in sodium transport in HAPE-prone subjects, and thereby further facilitate pulmonary oedema. Therefore, the aim of the current study was to measure the nasal potential difference (PD) in 21 HAPE-prone and 29 HAPE-resistant subjects at low altitude and 30 h after arrival at high altitude (4,559 m). High-altitude exposure significantly decreased the mean +/- SD nasal PD in HAPE-prone (18.0 +/- 6.2 versus 12.5 +/- 6.8 mV) but not in HAPE-resistant subjects (25.6 +/- 9.4 versus 22.9 +/- 9.2 mV). This altitude-induced decrease was not associated with an altered amiloride-sensitive fraction, but was associated with a significantly lower amiloride-insensitive fraction of the nasal PD. These findings provide evidence in vivo that an environmental factor may impair respiratory transepithelial sodium transport in humans. They are consistent with the concept that in high-altitude pulmonary oedema-susceptible subjects, the combination of a constitutive and an acquired defect in this transport mechanism facilitates the development of pulmonary oedema during high-altitude exposure.