Selective Alteration in Blood-Brain Barrier and Insulin Transport in Iron-Deficient Rats

Nutritional iron deficiency induced in rats causes a significant reduction in level of brain nonheme iron and is accompanied by selective reduction of dopamine D2 receptor Bmax. Our previous studies have clearly demonstrated that these alterations can be restored to normal by supplementation with ferrous sulfate; however, neither brain nonheme iron level nor dopamine D2 receptor Bmax can be increased beyond control values even after long-term iron therapy. The possibility that iron deficiency can induce the breakdown of the blood-brain barrier (BBB) was examined. A 70 and 100% increase in brain uptake index (BUI) for L-glucose and insulin, respectively, were noted in iron-deficient rats. However, the BUI for valine was decreased by 40%, and those for L-norepinephrine and glycine were unchanged. In addition, it was demonstrated that in normal rats insulin is transported into the brain. The data show that iron deficiency selectively affects the integrity of the BBB for insulin, glucose, and valine transport. Whether the effect of iron deficiency on the BBB is at the level of the capillary endothelial cell tight junction is not yet known. However, this study has shown that an important nutritional disorder (iron-deficiency anemia) has a profound effect on the BBB and brain function.     

Octocoral Tissue Provides Protection from Declining Oceanic pH

Increase in anthropogenic pCO₂ alters seawater chemistry and could lead to reduced calcification or skeleton dissolution of calcifiers and thereby weaken coral-reef structure. Studies have suggested that the complex and diverse responses in stony coral growth and calcification, as a result of elevated pCO₂, can be explained by the extent to which their soft tissues cover the underlying skeleton. This study compared the effects of decreased pH on the microstructural features of both in hospite (within the colony) and isolated sclerites (in the absence of tissue protection) of the zooxanthellate reef-dwelling octocoral Ovabunda macrospiculata. Colonies and isolated sclerites were maintained under normal (8.2) and reduced (7.6 and 7.3) pH conditions for up to 42 days. Both in hospite and isolated sclerites were then examined under SEM and ESEM microscopy in order to detect any microstructural changes. No differences were found in the microstructure of the in hospite sclerites between the control and the pH treatments. In stark contrast, the isolated sclerites revealed dissolution damage related to the acidity of the water. These findings suggest a protective role of the octocoral tissue against adverse pH conditions, thus maintaining them unharmed at high pCO₂. In light of the competition for space with the less resilient reef calcifiers, octocorals may thus have a significant advantage under greater than normal acidic conditions.     

Oxidation of 2-mercaptoacetyl-phenylalanyl-leucine,a specific inhibitor ofPseudomonas aeruginosa elastase,in the presence of the bacteria and its prevention

The compound 2-mercaptoacetyl-l-phenylalanyl-l-leucine (HSAc-Phe-Leu) is a specific and potent inhibitor ofPseudomonas aeruginosa elastase with demonstrated potential as a drug for the treatment ofPseudomonas eye infections. The thiol moiety of this compound is lost in the presence of the bacterial at a rate greater than that seen in the absence of the organisms. Tritium-labeled inhibitor was prepared and used to examine whether this accelerated loss is due to the uptake of the inhibitor by the bacteria or due to its modification by some bacterial products. Our results excluded by possibility of uptake and indicated that the loss of the thiol resulted from its oxidation to the inactive disulfide form. The oxidation reaction is probably catalyzed by a low molecular weight extracellular bacterial product, and is effectively prevented in the presence of sodium bisulfite. It is suggested that HSAc-Phe-Leu preparations used for further investigation of the inhibitor's therapeutic potential should include antoxidants such as sodium bisulfite to provide maximal inhibitory capacity.     

Changes in circadian rhythms of thermoregulation and motor activity in rats as a function of aging: effects of d-amphetamine and alpha-MSH

Thermoregulatory and motor activity circadian cycles are age-dependent. While the level of thermoregulation and motor activity remained almost at the same level during the first 1-15 months during the light portion of the 24-hr cycle, a significant decrease in the level of both rhythms was observed during the dark period. Therefore, older rats exhibited reversed cycles compared with younger rats. Treatments with d-amphetamine resulted in the enhancement of reversal of the cycles. Rats treated with alpha-MSH failed to exhibit a reversal of the cycles. While the effects of d-amphetamine are mediated by the brain DA mesolimbic pathway, it seems that alpha-MSH acts on the dopaminergic system at different sites of action.     

Electron-transfer quenching of nucleic acid-functionalized CdSe/ZnS quantum dots by doxorubicin: a versatile system for the optical detection of DNA, aptamer-substrate complexes and telomerase activity

The optical detection of DNA or the sensing of low-molecular-weight substrates or proteins by aptamer nucleic acids is a long term challenge in the design of biosensors. Similarly, the detection of the telomerase activity, a versatile biomarker of cancer cells, is important for rapid cancer diagnostics. We implement the luminescence quenching of the CdSe/ZnS quantum dots (QDs) as a versatile process to develop DNA sensors and aptasensors, and to design an analytical platform for the detection of telomerase activity. The formation of nucleic acid duplexes on QDs, or the assembly of aptamer-substrate complexes on the QDs (substrate=cocaine or thrombin) is accompanied by the intercalation of doxorubicin (DB) into the duplex domains of the resulting recognition complexes. The intercalated DB quenches the luminescence of the QDs, thus leading to the detection readout signal. Similarly, the telomerase-induced formation of the telomere chains on the QDs is followed by the hybridization of nucleic-acid units complementary to the telomere repeat units, and the intercalation of DB into the resulting duplex structure. The resulting luminescence quenching of the QDs provides an indicating signal for the activity of telomerase.     

The Indo-Pacific oyster Spondylus spinosus Schreibers, 1793 in the Eastern Mediterranean Sea: reproductive features

Populations of the Indo-Pacific invasive bivalve Spondylus spinosus in the Eastern Mediterranean occur at high densities and occupy vast areas of the rocky habitats along the Israeli coast where they are cemented to hard substratum in an oyster-like fashion. We studied the reproductive features of this bivalve in part of the area where it has invaded and found it to be gonochoric, featuring a reproducing population with a sex ratio of 1:1, annual gonad development and an inferred spawning period coinciding with the seasonal rise in seawater temperature. It is suggested that these reproductive features support high fertilisation rates and fecundity, thus contributing to the maintenance of its populations in the new environment.     

Irisin and the Metabolic Phenotype of Adults with Prader-Willi Syndrome

Context

Hyperphagia, low resting energy expenditure, and abnormal body composition contribute to severe obesity in Prader Willi syndrome (PWS). Irisin, a circulating myokine, stimulates “browning” of white adipose tissue resulting in increased energy expenditure and improved insulin sensitivity. Irisin has not been previously studied in PWS.

Objectives

Compare plasma and salivary irisin in PWS adults and normal controls. Examine the relationship of irisin to insulin sensitivity and plasma lipids.

Design and Study Participants

A fasting blood sample for glucose, lipids, insulin, leptin, adinopectin, and irisin was obtained from 22 PWS adults and 54 healthy BMI-matched volunteers. Saliva was collected for irisin assay in PWS and controls.

Results

Fasting glucose (77±9 vs 83±7mg/dl, p = 0.004), insulin (4.1±2.0 vs 7.9±4.7μU/ml, p<0.001), and triglycerides (74±34 vs 109±71mg/dl, p = 0.007) were lower in PWS than in controls. Insulin resistance (HOMA-IR) was lower (0.79±0.041 vs 1.63±1.02, p<0.001) and insulin sensitivity (QUICKI) was higher (0.41±0.04 vs 0.36±0.03, p<0.001) in PWS. Plasma irisin was similar in both groups, but salivary irisin (64.5±52.0 vs 33.0±12.1ng/ml), plasma leptin (33.5±24.2 vs 19.7±19.3ng/ml) and plasma adinopectin (13.0±10.8 vs 7.6±4.5μg/ml) were significantly greater in PWS (p<0.001). In PWS, plasma irisin showed positive Pearson correlations with total cholesterol (r = 0.58, p = 0.005), LDL-cholesterol (r = 0.59, p = 0.004), and leptin (r = 0.43, p = 0.045). Salivary irisin correlated negatively with HDL-cholesterol (r = -0.50, p = 0.043) and positively with LDL-cholesterol (r = 0.51, p = 0.037) and triglycerides (r = 0.50, p = 0.041).

Conclusions

Salivary irisin was markedly elevated in PWS although plasma irisin was similar to levels in controls. Significant associations with plasma lipids suggest that irisin may contribute to the metabolic phenotype of PWS.     

Prevalence of Celiac Disease in Latin America: A Systematic Review and Meta-Regression

BackgroundCeliac disease (CD) is an immune-mediated enteropathy triggered by the ingestion of gluten in susceptible individuals, and its prevalence varies depending on the studied population. Given that information on CD in Latin America is scarce, we aimed to investigate the prevalence of CD in this region of the world through a systematic review and meta-analysis.ConclusionsAlthough CD seems to be a rare condition in Colombians; the general prevalence of the disease in Latin Americans seemingly corresponds to a similar scenario observed in Europeans.