Beta-amyloid peptide potentiates inflammatory responses induced by lipopolysaccharide,interferon -gamma and 'advanced glycation endproducts' in a murine microglia cell line

beta-Amyloid (Abeta) plaques are characteristic hallmarks of Alzheimer's disease (AD). In AD, it has been suggested that activation of microglial cells might be the link between Abeta deposition and neuronal degeneration. Activated microglia are associated with senile plaques and produce free radicals and inflammatory cytokines. However, it is still not clear whether Abeta needs a prestimulated environment to exert its proinflammatory potential. Advanced glycation endproducts (AGEs), protein-bound oxidation products of sugars, have been shown to accumulate in senile plaques and could induce a silent but chronic inflammation in the AD brain. We tested whether Abeta acts as an amplifier of a submaximal proinflammatory response initiated by exposure to chicken egg albumin-AGE, lipopolysaccharide or interferon-gamma. Synthetic Abeta was used to produce three different samples (Abeta-fibrilar; Abeta-aggregated; Abeta-AGE), which were characterized for beta-sheeted fibrils by the thioflavin-T test and electron microscopy. As markers of microglial activation, nitric oxide, interleukin-6, macrophage-colony stimulation factor and tumour necrosis factor-alpha production was measured. All three Abeta samples alone could not induce a detectable microglial response. The combination of Abeta preparations, however, with the coinducers provoked a strong microglial response, whereby Abeta-AGE and fibrilar Abeta were more potent inflammatory signals than aggregated Abeta. Thus, Abeta in senile plaques can amplify microglial activation by a coexisting submaximal inflammatory stimulus. Hence, anti-inflammatory therapeutics could either target the primary proinflammatory signal (e.g. by limiting AGE-formation by AGE inhibitors or cross-link breakers) or the amplifyer Abeta (e.g. by limiting Abeta production by beta- or gamma-secretase inhibitors).     

Comparative Study of Tumor Targeting and Biodistribution of pH (Low) Insertion Peptides (pHLIP<Superscript>®</Superscript> Peptides) Conjugated with Different Fluorescent Dyes

Purpose

Acidification of extracellular space promotes tumor development, progression, and invasiveness. pH (low) insertion peptides (pHLIP^® peptides) belong to the class of pH-sensitive membrane peptides, which target acidic tumors and deliver imaging and/or therapeutic agents to cancer cells within tumors.

Procedures

Ex vivo fluorescent imaging of tissue and organs collected at various time points after administration of different pHLIP^® variants conjugated with fluorescent dyes of various polarity was performed. Methods of multivariate statistical analyses were employed to establish classification between fluorescently labeled pHLIP^® variants in multidimensional space of spectral parameters.

Results

The fluorescently labeled pHLIP^® variants were classified based on their biodistribution profile and ability of targeting of primary tumors. Also, submillimeter-sized metastatic lesions in lungs were identified by ex vivo imaging after intravenous administration of fluorescent pHLIP^® peptide.

Conclusions

Different cargo molecules conjugated with pHLIP^® peptides can alter biodistribution and tumor targeting. The obtained knowledge is essential for the design of novel pHLIP^®-based diagnostic and therapeutic agents targeting primary tumors and metastatic lesions.

     

Tolerance liability of diazepam is dependent on the dose used for protracted treatment

BackgroundBehavioral effects of benzodiazepines following repeated exposure vary according to the intrinsic efficacy of the benzodiazepine studied, treatment schedule and the behavioral parameters evaluated.MethodsWe applied the behavioral paradigms of spontaneous locomotor activity, elevated plus maze and grip strength to investigate the sedative, anxiolytic and myorelaxant effect of acute challenge with 2 mg/kg diazepam administered after 14 days of protracted treatment with 0.5, 2 or 10 mg/kg of diazepam. In addition, we studied the effects of everyday handling and intraperito-neal (ip) administration on animal behavior.ResultsTolerance to the sedative effect of 2 mg/kg diazepam ensued after 14 days of protracted treatment with 2 and 10 mg/kg of diazepam. In contrast, treatment with the lowest dose (0.5 mg/kg) of diazepam resulted in potentiation of the sedative effect of acute challenge with 2 mg/kg diazepam thus confounding the detection of the anxiolytic effect of diazepam. A sensitization-like response to the anxiolytic action of 2 mg/kg diazepam was seen after protracted treatment with the intermediate dose (2 mg/kg); however, anxiolytic effect was absent after protracted administration of the highest dose. Partial tolerance to the muscle relaxant effect of 2 mg/kg diazepam ensued after protracted treatment with diazepam regardless of the dose. Daily handling or ip administration did not alter the behavioral response to acute challenge with 2 mg/kg diazepam in all the three behavioral paradigms studied.ConclusionThe presented results showed that behavioral effects of acute challenge with diazepam were differently affected by the dose administered during protracted treatment.     

Circum-menopausal changes in women's preferences for sexually dimorphic shape cues in peer-aged faces

Recent studies suggest that post-menopausal women demonstrate stronger preferences for feminine characteristics in male and female faces than do pre-menopausal women, potentially reflecting stronger preferences for healthy men and greater derogation of attractive women among more fertile women. A limitation of this work was that it assessed circum-menopausal women's face preferences using images of young adults only. Here, we found that post-menopausal women demonstrated stronger preferences for feminine characteristics in male and female peer-aged faces that did pre-menopausal women. These data present novel evidence for circum-menopausal variation in face perception and confirm that the circum-menopausal variation in face preferences observed previously was not an artefact of the young faces employed as stimuli.     

Renal involvement in primary Sjogren syndrome of childhood: case report and literature review

Renal tubular acidosis (RTA) is common in adults with primary Sjogren syndrome (pSS) but to date this condition has only been identified in 12 pediatric cases of pSS. Here we present the case of a 13-year-old, otherwise asymptomatic girl in whom the search for the etiology of incidentally found nephrocalcinosis led to diagnosis of distal RTA and nephrogenic diabetes insipidus secondary to SS-associated tubulointerstitial nephritis. Immunosupressive treatment and alkali/electrolyte supplementation resulted in stable renal function over the 6-year follow-up. A review of the literature focuses on two aspects of pSS: (1) the difficulties in diagnosing pSS in childhood and (2) clinical–pathological features, treatment and outcome of renal tubulointerstitial disease in childhood pSS. SS should be considered in older children, particularly females with otherwise unexplained RTA. A careful search for other renal dysfunctions is necessary, and renal biopsy may be of value in assessing the extent of renal damage and the need for immunomodulatory therapy.     

Silencing of RhoA nucleotide exchange factor, ARHGEF3, reveals its unexpected role in iron uptake

Genomewide association meta-analysis studies have identified > 100 independent genetic loci associated with blood cell indices, including volume and count of platelets and erythrocytes. Although several of these loci encode known regulators of hematopoiesis, the mechanism by which most sequence variants exert their effect on blood cell formation remains elusive. An example is the Rho guanine nucleotide exchange factor, ARHGEF3, which was previously implicated by genomewide association meta-analysis studies in bone cell biology. Here, we report on the unexpected role of ARHGEF3 in regulation of iron uptake and erythroid cell maturation. Although early erythroid differentiation progressed normally, silencing of arhgef3 in Danio rerio resulted in microcytic and hypochromic anemia. This was rescued by intracellular supplementation of iron, showing that arhgef3-depleted erythroid cells are fully capable of hemoglobinization. Disruption of the arhgef3 target, RhoA, also produced severe anemia, which was, again, corrected by iron injection. Moreover, silencing of ARHGEF3 in erythromyeloblastoid cells K562 showed that the uptake of transferrin was severely impaired. Taken together, this is the first study to provide evidence for ARHGEF3 being a regulator of transferrin uptake in erythroid cells, through activation of RHOA.     

Lipophilic siderophores of Mycobacterium tuberculosis prevent cardiac reperfusion injury

Reperfusion injury, which occurs upon the reintroduction of blood flow to an ischemic organ, is responsible for considerable damage in heart attacks and strokes. However, no treatment for reperfusion injury is currently available. A major cause of reperfusion injury is the iron-mediated generation of hydroxyl radical (OH). In this study we have explored the capacity of novel iron chelators called “exochelins” to prevent reperfusion injury. Exochelins, siderophores of Mycobacterium tuberculosis, are unique iron chelators because they are lipid soluble, and hence able to enter cells rapidly. In the iron-free state, exochelins prevented OH formation. Desferri-exochelins prevented oxidative injury to cultured cardiac myocytes, and did so more rapidly and effectively than the nonlipid soluble iron chelator deferoxamine. The capacity of various desferri-exochelins to protect myocytes from oxidative injury varied directly with their solubility in lipid. Infused into isolated rabbit hearts during reperfusion after a period of ischemia, desferri-exochelins dramatically improved systolic and diastolic left ventricular function, preserved coronary flow, reduced release of the cardiac enzyme lactic dehydrogenase, and reduced myocardial concentrations of OH metabolites. Thus, highly diffusible desferri-exochelins block injury caused by OH production and have potential for the treatment of reperfusion injury.     

Recovery of motor function after stroke: a polymyography-based analysis

We present a method for assessing muscle activation patterns during goal-directed movement. We present a cohort study from a randomized clinical trial that followed the recovery of motor function during and after intensive gait training, assisted by sensor-driven, four-channel electrical stimulation. The instrument that we developed allows for the simultaneous recordings of up to 16 channels that are wirelessly sent to a host computer, which then provides feedback to the subject. The inputs to the portable instrument support electromyography (EMG) amplifiers, inertial sensors and goniometers. We show that this method is sensitive enough to show changes in muscle activation patterns in stroke patients before and after gait training (four weeks, five days a week, 30 min daily). We also show that the recovery decreases the differences between patterns of muscle activities (e.g., levels of muscle activations and median frequencies) assessed in hemiplegic and healthy subjects. This method allows for the analysis of muscle contributions and activation patterns; therefore, it might be possible to better understand the physiology behind the recovery of function. This EMG analysis provides a quantification of recovery that is a valuable addition to other measures, such as the Fugl-Meyer score, the Berg-Balance score, gait speed, and the symmetry index.     

Distribution of normal and pathological OGTTs among pregnant population and non-pregnant women with PCOS – the cross-sectional study

Both pregnancy, as physiological, and polycystic ovary syndrome (PCOS), as a pathological condition, carry the risk for developing glucose metabolism abnormalities. In this retrospective cross-sectional study, we hypothesized that pregnancy as a physiological condition carries a higher likelihood for abnormal oral glucose tolerance test (OGTT) results than PCOS as a pathological condition.We have compared the prevalence and likelihood ratios for abnormal OGTT results between non-pregnant women with PCOS (Group A) and pregnant women at 24 to 28 weeks of gestation (Group B). Participants of both study groups underwent glucose tolerance testing with 75 g glucose OGTT. During the study period, 7411 women were tested, 3932 women encompassed Group A, and 3479 women comprised Group B.The numbers of yearly tested pregnant women and the corresponding proportion of tested women among all study participants have decreased during the study period, from 766 to 131 and 89.1% to 20.5%, respectively. Group A had a significantly lower prevalence (4.4%) of pathological OGTT results compared to Group B (8.1%). This has resulted in a 45.427 likelihood ratio (P < .001) for abnormal OGTT results in pregnant women compared to non-pregnant women with PCOS.We might conclude that pregnancy could have a more challenging influence on glucose metabolism and that carries higher risks for abnormal glucose metabolism than PCOS. The awareness of obstetricians regarding physiological changes during pregnancy that predisposes abnormal glucose metabolism is decreasing over time and the compliance concerning OGTT testing of pregnant women is decreasing too.