Structure-based design of a new series of D-glutamic acid based inhibitors of bacterial UDP-N-acetylmuramoyl-L-alanine:D-glutamate ligase (MurD)

MurD ligase is one of the key enzymes participating in the intracellular steps of peptidoglycan biosynthesis and constitutes a viable target in the search for novel antibacterial drugs to combat bacterial drug-resistance. We have designed, synthesized, and evaluated a new series of D-glutamic acid-based Escherichia coli MurD inhibitors incorporating the 5-benzylidenethiazolidin-4-one scaffold. The crystal structure of 16 in the MurD active site has provided a good starting point for the design of structurally optimized inhibitors 73-75 endowed with improved MurD inhibitory potency (IC(50) between 3 and 7 μM). Inhibitors 74 and 75 showed weak activity against Gram-positive Staphylococcus aureus and Enterococcus faecalis. Compounds 73-75, with IC(50) values in the low micromolar range, represent the most potent D-Glu-based MurD inhibitors reported to date.     

Aluminum and Alzheimer's disease: after a century of controversy, is there a plausible link?

The brain is a highly compartmentalized organ exceptionally susceptible to accumulation of metabolic errors. Alzheimer's disease (AD) is the most prevalent neurodegenerative disease of the elderly and is characterized by regional specificity of neural aberrations associated with higher cognitive functions. Aluminum (Al) is the most abundant neurotoxic metal on earth, widely bioavailable to humans and repeatedly shown to accumulate in AD-susceptible neuronal foci. In spite of this, the role of Al in AD has been heavily disputed based on the following claims: 1) bioavailable Al cannot enter the brain in sufficient amounts to cause damage, 2) excess Al is efficiently excreted from the body, and 3) Al accumulation in neurons is a consequence rather than a cause of neuronal loss. Research, however, reveals that: 1) very small amounts of Al are needed to produce neurotoxicity and this criterion is satisfied through dietary Al intake, 2) Al sequesters different transport mechanisms to actively traverse brain barriers, 3) incremental acquisition of small amounts of Al over a lifetime favors its selective accumulation in brain tissues, and 4) since 1911, experimental evidence has repeatedly demonstrated that chronic Al intoxication reproduces neuropathological hallmarks of AD. Misconceptions about Al bioavailability may have misled scientists regarding the significance of Al in the pathogenesis of AD. The hypothesis that Al significantly contributes to AD is built upon very solid experimental evidence and should not be dismissed. Immediate steps should be taken to lessen human exposure to Al, which may be the single most aggravating and avoidable factor related to AD.     

Pathogenesis and management issues for non-alcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has, although it is a very common disorder, only relatively recently gained broader interest among physicians and scientists.Fatty liver has been documented in up to 10 to 15percent of normal individuals and 70 to 80 percent of obese individuals. Although the pathophysiology of NAFLD is still subject to intensive research, several players and mechanisms have been suggested based on the substantial evidence. Excessive hepatocyte triglyceride accumulation resulting from insulin resistance is the first step in the proposed 'two hit' model of the pathogenesis of NAFLD. Oxidative stress resulting from mitochondrial fatty acids oxidation, NF-κB-dependent inflammatory cytokine expression and adipocytokines are all considered to be the potential factors causing second hits which lead to hepatocyte injury, inflammation and fibrosis. Although it was initially believed that NAFLD is a completely benign disorder, histologic follow-up studies have showed that fibrosis progression occurs in about a third of patients. A small number of patients with NAFLD eventually ends up with end-stage liver disease and even hepatocellular carcinoma. Although liver biopsy is currently the only way to confirm the NAFLD diagnosis and distinguish between fatty liver alone and NASH, no guidelines or firm recommendations can still be made as for when and in whom it is necessary. Increased physical activity, gradual weight reduction and in selected cases bariatric surgery remain the mainstay of NAFLD therapy. Studies with pharmacologic agents are showing promising results, but available data are still insufficient to make specific recommendations; their use therefore remains highly individual.     

Anion-exchange chromatography using short monolithic columns as a complementary technique for human serum albumin depletion prior to human plasma proteome analysis

In order to enable the detection of low abundance proteins from human plasma, it is necessary to remove high abundance proteins. Among them, human serum albumin and immunoglobulin G represent more than 75% of all such proteins. In this paper, the characterization of short monolithic columns was performed followed by the optimization of a multidimensional approach, known as conjoint liquid chromatography, to deplete human serum albumin and immunoglobulin G from a human plasma sample. Two different chromatographic modes were used: ion-exchange chromatography and affinity chromatography. A monolithic stationary phase (convective interaction media disk) bearing strong anion-exchange groups and another immobilized with protein G were placed in series into one housing. The optimal binding conditions were found that removed a majority of human serum albumin and immunoglobulin G from the human plasma sample. This method was compared to the depletion using a combination of pseudo-affinity and affinity columns. The results of the human serum albumin and immunoglobulin G depletion were confirmed by 2D electrophoresis. It has been shown that anion-exchange and affinity chromatography using convective interaction media monolithic columns can represent an efficient complementary technique for human serum albumin and immunoglobulin G removal from human plasma.     

Illness Perception and Cardiovascular Risk Factors in Patients with Type 2 Diabetes: Cross-sectional Questionnaire Study

Aim

To investigate illness perception in patients with type 2 diabetes mellitus and its association with the degree of control over relevant cardiovascular risk factors.

Methods

A cross-sectional questionnaire-based study was performed from June 2007 to March 2008. A stratified random sample of 46 Croatian general practitioners was asked to select, using systematic sampling, the first 6 patients with type 2 diabetes mellitus aged ≥18 years who visited them for consultation during the study period. Data on 250 patients included patient illness perception assessment (Brief Illness Perception Questionnaire, IPQ), cardiovascular risk factors, and socio-demographic data.

Results

The patients’ mean age was 63.0 ± 10.9 years and mean duration of diabetes was 9.3 ± 7.8 years. The patients’ illness perception assessment on an 11-point (0 to 10) scale showed the highest median scores (interquartile range): 10 (8 to 10) for “timeline” and 8 (7 to 9) for “treatment control,” followed by 7 (5 to 8) for “personal control,” 7 (5 to 9) for “understanding,” 5 (3 to 7) for “consequences,” 6 (4 to 7) for “concern,” and 5 (2 to 7) for “emotional response.” The lowest score was 3 (1 to 5) for “identity.” Multivariate logistic regression showed that the Brief IPQ item “concern” (P < 0.001) was a significant predictor of body mass index; “personal control” (P < 0.001) and “concern” (P = 0.048) were significant predictors of fasting blood glucose; “treatment control” (P = 0.009) was a significant predictor of total cholesterol; and “understanding” (P = 0.010) was a significant predictor of blood pressure.

Conclusion

As patients'' beliefs seem to be associated with the degree of control over cardiovascular risk factors, they should be included in routine clinical assessments.Although the quality of guidelines to diabetes care appears to be improved, a poor metabolic control over the illness has been found in as many as 30%-60% of patients with type 2 diabetes treated in routine general practice (GP) settings (1). Despite of the vital role of health care providers, the responsibility for diabetes management largely rests on the patient. Ninety-five percent of health-related decisions are to be made by patients on a daily basis, without even consulting with health care professionals (2,3). These decisions are related to diet, tobacco smoking, foot care, and exercising, adherence to daily urine or blood glucose monitoring, and drug regulation, which should all be harmonized and embedded into working, domestic, and leisure routines. Research has shown the enhancement of active participation and self-care to be the key factor responsible for the improvement of outcomes in diabetic patients (4). Furthermore, there is a growing body of evidence corroborating that the perception of the disease plays an important role in the degree of compliance (5-7).The study on individual perceptions of illness stemmed from the research on health-threat communication (7). Different health behavior theories have been developed to describe individual response to a perceived health threat and the manner of coping with it. One of the widely adopted models is the self-regulation model introduced by Leventhal et al (8,9). The self-regulation model assumes that health-related behavioral patterns are a result of complex multi-faceted representations of illness. Cognitive representation of illness embraces 5 core dimensions (8): identity (ie, label and symptoms that a person ascribes to his or her illness); consequences (ie, expected effects and outcomes of the illness); cause (ie, causal attribution that a patient assigns to his or her illness); timeline (ie, the expected duration of illness viewed from the patient’s perspective); and cure or control modalities (ie, the extent to which a patient believes he/she can recover from the illness or place it under control). Emotional representation also includes negative reactions to the illness, such as fear, anger, and distress. Other studies have provided a quantitative support as to the existence of structural relations between the 5 illness representation components described by Leventhal (8), and to the existence of links between illness perceptions and a number of psychological outcomes, such as coping, mood, functional adaptation, and compliance (9-21).While researchers have often examined the relation of illness perception with psychological outcomes, its relation with cardiovascular risk factors has been studied only on rare occasions (4,22,23). We find this area important, since diabetes and cardiovascular disease often appear as “the two sides of the same coin” (24). Furthermore, in type 2 diabetes, the presence of cardiovascular risk factors at least doubles the risk of cardiovascular death (1). As with most European transitional countries, in Croatia cardiovascular disease is the leading cause of death and accounts for more than half of the overall mortality (25).The aim of this study was to investigate the illness perception in patients with type 2 diabetes and its association with the degree of control over cardiovascular risk factors.     

Role of cyclic tertiary amine bioactivation to reactive iminium species: structure toxicity relationship

Cytochrome P450-mediated bioactivation of drugs to reactive metabolites has been reported to be the first step in many adverse drug reactions. Metabolic activation of cyclic tertiary amines often generates a number of oxidative products including N-dealkylation, ring hydroxylation, α-carbonyl formation, N-oxygenation, and ring opening metabolites that can be formed through iminium ion intermediates. Therapeutic pharmaceuticals and their metabolites containing a cyclic tertiary amine structure have the potential to form iminium intermediates that are reactive toward nucleophilic macromolecules. Examples of cyclic tertiary amines that have the potential for forming reactive iminium intermediates include the piperazines, piperidines, 4-hydroxypiperidines, 4-fluoropiperidines and related compounds, pyrrolidines and N-alkyltetrahydroquinolines. Major themes explored in this review include bioactivation reactions for cyclic tertiary amines, which are responsible for the formation of iminium intermediates, together with some representative examples of drugs and guidance for discovery scientists in applying the information to minimize the bioactivation potential of cyclic amine-based compounds in drug discovery. Potential strategies to abrogate reactive iminium intermediate formation are also discussed.     

Does shifting to professional emergency department staffing affect the decision for chest radiography?

BACKGROUND: The study aims to determine whether shifting to professional emergency department(ED) teams leads to a higher rate of radiologic workup.METHODS: We retrospectively analyzed a total of 2,000 patients presenting to the ED of a tertiary teaching hospital in two time periods: group 1(G1) comprised 1,000 consecutive patients enrolled from December 21, 2012 to January 5, 2013(all patients were examined by an internal medicine specialist);group 2(G2) comprised 1,000 consecutive patients enrolled from December 21, 2018 to January 3, 2019(all patients were examined by an emergency physician).RESULTS: The chest X-ray(CXR) was performed in 40.6% of all patients. There was no difference in the frequency of CXR(38.9% in G1 vs. 42.3% in G2, P=0.152). More CXRs were performed in G2 patients older than 65 years, in female patients older than 65 years, in patients presenting during the evening and night shifts or off-hours, in patients with a history of malignancy, in patients with gastrointestinal bleeding, and in patients with bradycardia, but fewer in patients presenting with arrhythmia. No difference in the rates of pathological CXR was found(47.3% in G1 vs. 52.2% in G2, P=0.186). Compared with G2, higher sensitivity and specificity were obtained for the binary logistic regression model predicting pathological findings in G1.CONCLUSIONS: Shifting to professional ED teams does not increase radiologic workup. By implementing deliberate usage of ultrasound, some self-governing procedures, case-oriented investigations, and center-specific recommendations, unnecessary radiologic workup can be avoided. Professional ED teams could lead to a higher standard of emergency care.     

Sodium-to-Potassium Ratio as an Indicator of Diet Quality in Healthy Pregnant Women

This study aimed to investigate diet quality in healthy pregnant women based on the Na-to-K ratio from 24 h urine sample and food frequency questionnaire (FFQ), to compare dietary micro- and macronutrient intake with current nutritional recommendations (RDA), and to investigate whether gestational weight gain (GWG) is associated with Na-to-K ratio and diet quality during pregnancy in general. Sixty-four healthy pregnant women between 37 and 40 weeks of gestation participated in the study. Participants’ GWG, body composition, molar 24 h urine Na-to-K ratio, and FFQ data on average daily total energy, food groups, and micro-/macronutrient intake were obtained. A Na-to-K ratio of 2.68 (1.11–5.24) does not meet nutrition quality and is higher than the WHO recommendations due to excessive sodium and insufficient potassium intake. FFQ Na-to-K ratio was associated with a higher daily intake of soups, sauces, cereals, fats, and oils and a low intake of fruit and non-alcoholic beverages. A total of 49% of pregnant women exhibited excessive GWG, which was attributed to the increase in adipose tissue mass. GWG was not associated with total energy but may be the result of insufficient physical activity during pregnancy. Daily intake of vitamin D, vitamin E, folate, niacin, riboflavin, calcium, iron, and zinc was suboptimal compared to RDA.     

Dietary,locomotory, and metabolic reactions of Abax parallelus (Coleoptera,Carabidae) to acute thiamethoxam intoxication

Carabids (Coleoptera: Carabidae) are abundant predators in ecosystems and serve as pest biocontrol in agroecosystems and forestry. Here we test the impact of thiamethoxam, among the most used neonicotinoids on the consumption rate, locomotion, metabolomics, and oxidative stress level measuring superoxide dismutase (SOD) activity in a predatory carabid, Abax parallelus (Duftschmid, 1812), after acute exposure in the laboratory trials, to get additional data that might link the use of pesticides and predation efficiency. Beetles were exposed to increasing concentrations of thiamethoxam by dipping method, and left to feed overnight prior to the assays. The results showed that individuals treated with higher concentrations of thiamethoxam (20 and 40 mg/L) consumed significantly less food per body weight and had a higher share of intoxicated and moribund individuals. The mass of consumed food per beetle body weight and observed locomotion did not differ significantly between control and groups treated with lower concentrations of thiamethoxam. There are significant differences in concentrations of some metabolites between treated and control individuals, primary in succinate and d-glucose, indicating a disruption in energy production. On the other hand, there is no statistically significant differences in SOD activity among the groups. To conclude, acute exposure to thiamethoxam can result in negative sub-lethal effects in predatory activity and energy budget, while the effects of long-term exposure to lower doses require further research, as well as field assessment on the predation efficiency after pesticide application.

     

Challenges in the recovery of the genetic data from human remains found on the Western Balkan migration route

International Journal of Legal Medicine - Traditional DNA-based identification of human remains relies on the system of matching STR profile of the deceased with the family references or antemortem...