High-Throughput Analysis of Antimalarial Susceptibility Data by the WorldWide Antimalarial Resistance Network (WWARN) In Vitro Analysis and Reporting Tool

Assessment of in vitro susceptibility is a fundamental component of antimalarial surveillance studies, but wide variations in the measurement of parasite growth and the calculation of inhibitory constants make comparisons of data from different laboratories difficult. Here we describe a Web-based, high-throughput in vitro analysis and reporting tool (IVART) generating inhibitory constants for large data sets. Fourteen primary data sets examining laboratory-determined susceptibility to artemisinin derivatives and artemisinin combination therapy partner drugs were collated from 11 laboratories. Drug concentrations associated with half-maximal inhibition of growth (IC₅₀s) were determined by a modified sigmoid E_max model-fitting algorithm, allowing standardized analysis of 7,350 concentration-inhibition assays involving 1,592 isolates. Examination of concentration-inhibition data revealed evidence of apparent paradoxical growth at high concentrations of nonartemisinin drugs, supporting amendment of the method for calculating the maximal drug effect in each assay. Criteria for defining more-reliable IC₅₀s based on estimated confidence intervals and growth ratios improved correlation coefficients for the drug pairs mefloquine-quinine and chloroquine-desethylamodiaquine in 9 of 11 and 8 of 8 data sets, respectively. Further analysis showed that maximal drug inhibition was higher for artemisinins than for other drugs, particularly in ELISA (enzyme-linked immunosorbent assay)-based assays, a finding consistent with the earlier onset of action of these drugs in the parasite life cycle. This is the first high-throughput analytical approach to apply consistent constraints and reliability criteria to large, diverse antimalarial susceptibility data sets. The data also illustrate the distinct biological properties of artemisinins and underline the need to apply more sensitive approaches to assessing in vitro susceptibility to these drugs.     

Joint analysis of individual participants’ data from 17 studies on the association of the IL6 variant -174G>C with circulating glucose levels,interleukin-6 levels,and body mass index

Background. Several studies have investigated associations between the -174G>C single nucleotide polymorphism (rs1800795) of the IL6 gene and phenotypes related to type 2 diabetes mellitus (T2DM) but presented inconsistent results.

Aims. This joint analysis aimed to clarify whether IL6 -174G>C was associated with glucose and circulating interleukin-6 concentrations as well as body mass index (BMI).

Methods. Individual-level data from all studies of the IL6-T2DM consortium on Caucasian subjects with available BMI were collected. As study-specific estimates did not show heterogeneity (P>0.1), they were combined by using the inverse-variance fixed-effect model.

Results. The main analysis included 9440, 7398, 24,117, or 5659 non-diabetic and manifest T2DM subjects for fasting glucose, 2-hour glucose, BMI, or circulating interleukin-6 levels, respectively. IL6 -174 C-allele carriers had significantly lower fasting glucose (?0.091 mmol/L, P=0.014). There was no evidence for association between IL6 -174G>C and BMI or interleukin-6 levels, except in some subgroups.

Conclusions. Our data suggest that C-allele carriers of the IL6 -174G>C polymorphism have lower fasting glucose levels on average, which substantiates previous findings of decreased T2DM risk of these subjects.     

A Longitudinal Comparison of Arm Morbidity in Stage I–II Breast Cancer Patients Treated with Sentinel Lymph Node Biopsy,Sentinel Lymph Node Biopsy Followed by Completion Lymph Node Dissection,or Axillary Lymph Node Dissection

Background  

Long-term shoulder and arm function following sentinel lymph node biopsy (SLNB) may surpass that following complete axillary lymph node dissection (CLND) or axillary lymph node dissection (ALND). We objectively examined the morbidity and compared outcomes after SLNB, SLNB + CLND, and ALND in stage I/II breast cancer patients.     

Glycemia Determines the Effect of Type 2 Diabetes Risk Genes on Insulin Secretion

OBJECTIVE

Several single nucleotide polymorphisms (SNPs) in diabetes risk genes reduce glucose- and/or incretin-induced insulin secretion. Here, we investigated interactions between glycemia and such diabetes risk polymorphisms.

RESEARCH DESIGN AND METHODS

Insulin secretion was assessed by insulinogenic index and areas under the curve of C-peptide/glucose in 1,576 subjects using an oral glucose tolerance test (OGTT). Participants were genotyped for 10 diabetes risk SNPs associated with β-cell dysfunction: rs5215 (KCNJ11), rs13266634 (SLC30A8), rs7754840 (CDKAL1), rs10811661 (CDKN2A/2B), rs10830963 (MTNR1B), rs7903146 (TCF7L2), rs10010131 (WFS1), rs7923837 (HHEX), rs151290 (KCNQ1), and rs4402960 (IGF2BP2).Furthermore, the impact of the interaction between genetic variation in TCF7L2 and glycemia on changes in insulin secretion was tested in 315 individuals taking part in a lifestyle intervention study.

RESULTS

For the SNPs in TCF7L2 and WFS1, we found a significant interaction between glucose control and insulin secretion (all P ≤ 0.0018 for glucose × genotype). When plotting insulin secretion against glucose at 120 min OGTT, the compromising SNP effects on insulin secretion are most apparent under high glucose. In the longitudinal study, rs7903146 in TCF7L2 showed a significant interaction with baseline glucose tolerance upon change in insulin secretion (P = 0.0027). Increased glucose levels at baseline predicted an increase in insulin secretion upon improvement of glycemia by lifestyle intervention only in carriers of the risk alleles.

CONCLUSIONS

For the diabetes risk genes TCF7L2 and WFS1, which are associated with impaired incretin signaling, the level of glycemia determines SNP effects on insulin secretion. This indicates the increasing relevance of these SNPs during the progression of prediabetes stages toward clinically overt type 2 diabetes.Type 2 diabetes is a disorder characterized by chronically elevated blood glucose levels due to insulin resistance and a relative lack of compensatory pancreatic insulin secretion. Environmental triggers such as a sedentary lifestyle, physical inactivity, and increased body weight play an important role in the development of the disease. In this regard, genetics and especially gene-environment interactions play an important role. Recent research revealed more than 25 gene variants leading to a higher risk for the development of type 2 diabetes (1). Interestingly, most of the diabetes risk genes alter β-cell function (1). This supports the hypothesis that the main genetic effect in the development of type 2 diabetes could be impaired insulin secretion. Neither environmental triggers nor genetics alone can explain the multifactorial disease type 2 diabetes, thus a close interaction between both is presumed (2–4). Hence, environmental influences may determine an individual''s susceptibility for single nucleotide polymorphism (SNP) effects, or vice versa genotype may designate a person''s susceptibility toward environmental factors.One “environmental” factor that plays a role early in the pathogenesis of type 2 diabetes is elevated glucose. It is well known that years before type 2 diabetes occurs, glucose control is altered, as reflected by higher fasting glucose and/or higher postprandial glucose (5). High glucose exerts unfavorable effects on insulin sensitivity and secretion, known as glucotoxicity (6,7). On the other hand, elevated glucose levels are needed for the incretin effect. Glucagon-like peptide 1–induced insulin secretion becomes fully active only in the hyperglycemic range (8,9). Incretin-dependent insulin secretion might therefore be of particular importance when compensatory insulin hypersecretion is required.The aim of this study was to investigate whether glycemia influences the effects of genetic variation associated with type 2 diabetes on insulin secretion. We therefore studied 10 genome-wide association study–derived variants that were furthermore found to influence β-cell function in subsequent studies (rev. in 1,10). Of these, 2 (in the TCF7L2 and WFS1 loci) are associated with incretin-stimulated insulin secretion (1). As the magnitude of incretin-stimulated insulin secretion is dependent on elevated glucose levels (8,9), we hypothesized that glucose levels specifically interact with the effect of those SNPs on insulin secretion both in cross-sectional and longitudinal intervention studies.     

Amnesic Concentrations of the Nonimmobilizer 1,2-Dichlorohexafluorocyclobutane (F6, 2N) and Isoflurane Alter Hippocampal θ Oscillations In Vivo

Background: Drug-induced temporary amnesia is one of the principal goals of general anesthesia. The nonimmobilizer 1,2-dichlorohexafluorocyclobutane (F6, also termed 2N) impairs hippocampus-dependent learning at relative, i.e., lipophilicity-corrected, concentrations similar to isoflurane. Hippocampal [theta] oscillations facilitate mnemonic processes in vivo and synaptic plasticity (a cellular model of memory) in vitro and are thought to represent a circuit level phenomenon that supports memory encoding. Therefore, the authors investigated the effects of F6 and isoflurane on [theta] oscillations (4-12 Hz).

Methods: Thirteen adult rats were implanted with multichannel depth electrodes to measure the microelectroencephalogram and were exposed to a range of concentrations of isoflurane and F6 spanning the concentrations that produce amnesia. Five of these animals also underwent control experiments without drug injection. The authors recorded the behavioral state and hippocampal field potentials. They confirmed the electrode location postmortem by histology.

Results: The tested concentrations for isoflurane and F6 ranged from 0.035% to 0.77% and from 0.5% to 3.6%, respectively. Isoflurane increased the fraction of time that the animals remained immobile, consistent with sedation, whereas F6 had the opposite effect. Electroencephalographic power in the [theta] band was less when the animals were immobile than when they explored their environment. F6 suppressed the power of oscillations in the [theta] band. Isoflurane slowed [theta] oscillations without reducing total power in the [theta] band.     

Survival trends and predictors of mortality in severe pelvic trauma: estimates from the German Pelvic Trauma Registry Initiative

Study objective

To determine longitudinal trends in mortality, and the contribution of specific injury characteristics and treatment modalities to the risk of a fatal outcome after severe and complex pelvic trauma.

Methods

We studied 5048 patients with pelvic ring fractures enrolled in the German Pelvic Trauma Registry Initiative between 1991 and 1993, 1998 and 2000, and 2004 and 2006. Complete datasets were available for 5014 cases, including 508 complex injuries, defined as unstable fractures with severe peri-pelvic soft tissue and organ laceration. Multivariable mixed-effects logistic regression analysis was employed to evaluate the impact of demographic, injury- and treatment-associated variables on all-cause in-hospital mortality.

Results

All-cause in-hospital mortality declined from 8% (39/466) in 1991 to 5% (33/638) in 2006. Controlling for age, Injury Severity Score, pelvic vessel injury, the need for emergency laparotomy, and application of a pelvic clamp, the odds ratio (OR) per annum was 0.94 (95% confidence interval [CI] 0.91–0.96). However, the risk of death did not decrease significantly in patients with complex injuries (OR 0.98, 95% CI 0.93–1.03). Raw mortality associated with this type of injury was 18% (95% CI 9–32%) in 2006.

Conclusion

In contrast to an overall decline in trauma mortality, complex pelvic ring injuries remain associated with a significant risk of death. Awareness of this potentially life-threatening condition should be increased amongst trauma care professionals, and early management protocols need to be implemented to improve the survival prognosis.     

Prognosis and Determinants of Outcome Following Locoregional or Distant Recurrence in Patients with Cutaneous Melanoma

Objective Information on prognosis for patients with cutaneous melanoma after locoregional or distant recurrence is sparse and controversial. The aim of this study was to analyze factors influencing outcome after the development of a first relapse. Methods Information was extracted from the Sydney Melanoma Unit database for 873 melanoma patients with American Joint Committee on Cancer (AJCC) Stage I and II disease treated between 1960 and 2002 who relapsed following treatment of their primary melanoma. Clinical and pathologic factors predicting survival were analyzed using the Cox proportional hazards regression model. Results Initial presentation of recurrence was local: 95 patients (10.9%), in transit: 86 patients (9.9%), regional lymph node: 300 patients (34.4%), and distant: 392 patients (44.9%). Independent prognostic factors for survival of the 481 patients with only locoregional recurrence were type of recurrence, primary tumor ulceration, and patient age. Predictors for longer survival in the 392 patients with distant metastasis at the time of first presentation with recurrence were lung vs other sites and diagnosis of relapse after 1990 compared with diagnosis before 1980. Conclusions The type of recurrence is the most important prognostic factor in melanoma patients who relapse. Primary tumor ulceration is the most important pathologic predictor. The results of this study suggest that management of distant metastases may have improved over the last 25 years, but many confounders and improved staging techniques make assessment of this unreliable.     

S-Classification of Sentinel Lymph Node Predicts Axillary Nonsentinel Lymph Node Status in Patients with Breast Cancer

Background One-half of breast cancer patients with positive sentinel lymph node (SN) have no further metastases in the axillary lymph node basin. The aim of the present study was to identify patients with positive SN who are unlikely to have further metastases in the axillary lymph node basin, using a new classification of SN, namely the S-classification. Methods Specimens of positive SN were subjected to a pathological review according to the previously published S-classification. S-stages of positive SN were correlated with the status of further metastases in the axillary lymph node basin after axillary lymph node dissection (ALND). Results Of 117 patients who underwent sentinel lymph node biopsy, 36 (30.8%) had a positive SN and were subjected to level I and II ALND. The occurrence of positive nonsentinel nodes was significantly related to the S-stage of SN. No patient with stage SI had additional metastases in the nonsentinel lymph nodes, while 14.3% of patients with SII stage disease and 60.9 % of patients with SIII disease had other non-SN that were metastatic. Conclusion S-stages of positive SN are highly predictive for axillary nonsentinel node status. Especially patients with SI sentinel node metastases appear to be at low risk for further nonsentinel node metastases.