Targeting Spare CC Chemokine Receptor 5 (CCR5) as a Principle to Inhibit HIV-1 Entry

CCR5 binds the chemokines CCL3, CCL4, and CCL5 and is the major coreceptor for HIV-1 entry into target cells. Chemokines are supposed to form a natural barrier against human immunodeficiency virus, type 1 (HIV-1) infection. However, we showed that their antiviral activity is limited by CCR5 adopting low-chemokine affinity conformations at the cell surface. Here, we investigated whether a pool of CCR5 that is not stabilized by chemokines could represent a target for inhibiting HIV infection. We exploited the characteristics of the chemokine analog PSC-RANTES (N-α-(n-nonanoyl)-des-Ser(1)-[l-thioprolyl(2), l-cyclohexylglycyl(3)]-RANTES(4-68)), which displays potent anti-HIV-1 activity. We show that native chemokines fail to prevent high-affinity binding of PSC-RANTES, analog-mediated calcium release (in desensitization assays), and analog-mediated CCR5 internalization. These results indicate that a pool of spare CCR5 may bind PSC-RANTES but not native chemokines. Improved recognition of CCR5 by PSC-RANTES may explain why the analog promotes higher amounts of β-arrestin 2·CCR5 complexes, thereby increasing CCR5 down-regulation and HIV-1 inhibition. Together, these results highlight that spare CCR5, which might permit HIV-1 to escape from chemokines, should be targeted for efficient viral blockade.     

Serum Paraoxonase and Arylesterase Activities and Oxidative Stress Levels in Patients with SSRI Intoxication

Oxidative stress is a critical route of damage in various psychological stress-induced disorders, such as depression. Paraoxonase-1 (PON1) plays an important role as an endogenous free-radical scavenging molecule. The aim of this study was to evaluate the influence of serum PON1 activity and oxidative stress in patients with selective serotonin reuptake inhibitor (SSRI) intoxication. A total of 11 patients with SSRI intoxication and 20 healthy controls were enrolled. The serum total antioxidant capacity (TAC) and malondialdehyde (MDA) levels, as well as the paraoxonase and arylesterase activities, were measured spectrophotometrically. The serum TAC levels and the paraoxonase and arylesterase activities were significantly lower (for all, p < 0.001), whereas the serum MDA levels were significantly higher in the patients with SSRI intoxication than in the controls (p < 0.001). These results indicated that decreased PON1 activity and increased oxidative stress represent alternative mechanisms in SSRI toxicity. More studies are needed to elucidate the role of PON1 activity in the etiology of SSRI intoxication.     

The regulatory effect of melatonin on physiological,biochemical and molecular parameters in cold-stressed wheat seedlings

We investigated the possible mediatory role of melatonin in protecting wheat plants from cold stress. Ten-day-old wheat seedlings were pretreated with 1 mmol l^?1 melatonin for 12 h and subsequently exposed to stress conditions at 5/2 °C (day/night) for 3 days. Cold stress caused serious reductions in leaf surface area, water content, and photosynthetic pigment content, whereas melatonin application attenuated these reductions. Accumulation of reactive oxygen species (ROS), including superoxide and hydrogen peroxide, was very high in cold-stressed plants and caused lipid peroxidation in membranes. Concomitantly, ROS damaged the DNA profile and negatively influenced expression and/or activity of many enzymes, including RuBisCo. When compared to controls, cold-stressed plants had higher activities of the antioxidant enzymes superoxide dismutase, guaicol peroxidase, ascorbate peroxidase, and glutathione reductase and higher levels of the antioxidant compounds total ascorbate, reduced ascorbate, total glutathione, reduced glutathione, and phenolic substances; however, this elevation could not cope with the destructive effects of cold stress. Melatonin-pretreated plants exhibited greater increases in these parameters comparison with untreated cold-stressed plants. Isozyme bands monitored in native gel and RuBisCo expression supported these changes. Also, due to the cold-induced increase in dehydroascorbate and oxidized glutathione, the corrupted redox status in the cell was ameliorated by melatonin application. Similarly, levels of the osmoprotectants total soluble protein, carbohydrate, and proline were also increased by cold stress; however, melatonin-applied seedlings had a higher content of these solutes in comparison to untreated cold-stressed plants. We suggest that melatonin can improve plant resistance to cold stress in wheat seedlings by directly scavenging ROS and by modulating redox balance and other defence mechanisms.     

Effect of preventive supplementation with zinc and other micronutrients on non-malarial morbidity in tanzanian pre-school children: a randomized trial

Background

The efficacy of preventive zinc supplementation against diarrhea and respiratory illness may depend on simultaneous supplementation with other micronutrients. We aimed to assess the effect of supplementation with zinc and multiple micronutrients on diarrhea and other causes of non-malarial morbidity.

Methods and Findings

Rural Tanzanian children (n = 612) aged 6–60 months and with height-for-age z-score < –1.5 SD were randomized to daily supplementation with zinc (10 mg) alone, multi-nutrients without zinc, multi-nutrients with zinc, or placebo. Children were followed for an average of 45 weeks. During follow-up, we recorded morbidity episodes. We found no evidence that concurrent supplementation with multi-nutrients influenced the magnitude of the effect of zinc on rates of diarrhea, respiratory illness, fever without localizing signs, or other illness (guardian-reported illness with symptoms involving skin, ears, eyes and abscesses, but excluding trauma or burns). Zinc supplementation reduced the hazard rate of diarrhea by 24% (4%–40%). By contrast, multi-nutrients seemed to increase this rate (HR; 95% CI: 1.19; 0.94–1.50), particularly in children with asymptomatic Giardia infection at baseline (2.03; 1.24–3.32). Zinc also protected against episodes of fever without localizing signs (0.75; 0.57–0.96), but we found no evidence that it reduced the overall number of clinic visits.

Conclusions

We found no evidence that the efficacy of zinc supplements in reducing diarrhea rates is enhanced by concurrent supplementation with other micronutrients. By reducing rates of fever without localizing signs, supplementation with zinc may reduce inappropriate drug use with anti-malarial medications and antibiotics.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00623857","term_id":"NCT00623857"}}NCT00623857     

Comparison of four established questionnaires to identify highway bus drivers at risk for obstructive sleep apnea in Turkey

In Turkey, all heavy-vehicle driver’s license applicants older than 45 years and with body mass index (BMI) >25 kg/m² are required to have polysomnography (PSG). However, this law is usually overlooked in practice due to the large number of applications. We aimed to assess the usefulness of four standardized questionnaires: Berlin, STOP, STOP-BANG and OSA50, in identifying the high-risk bus drivers for obstructive sleep apnea (OSA). Ninety highway bus drivers underwent polysomnography and completed four questionnaires. They also underwent otolaryngologic evaluation and blood testing for probable co-existing conditions such as diabetes and hypothyroidism. Neck circumference, BMI, waist circumference, prevalence of OSA and metabolic syndrome, oxygen desaturation index and duration of sleep associated with less than 90% saturation were significantly higher and mean oxygen saturation was significantly lower in drivers >45 years old than drivers <45 years old. STOP-BANG questionnaire had the highest sensitivity (87%) and the highest negative predictive value (NPV) (76%) in identifying high-risk for OSA. A cut off of 45 years old is suitable in screening highway bus drivers for OSA. Among the four questionnaires, STOP-BANG questionnaire had the highest sensitivity and negative predictive value (NPV) in identifying high risk patients for OSA in highway bus drivers and can be safely used as a screening test in this group.

     

Toxic Metals in Breast Milk Samples from Ankara, Turkey: Assessment of Lead, Cadmium, Nickel, and Arsenic Levels

Toxic metals are one of the significant groups of chemical contaminants that humans are exposed to by oral, inhalation, and dermal routes. Exposure to these chemicals begins with intrauterine life and continues during lactation period at the first years of life. Breastfeeding has a much more special place than other nutrition options for infants. However, when possibility of contaminant transfer by breast milk is considered, its safety and quality is essential. Regarding infant and mother health and limited number of information on this field in Turkey, measuring contamination levels in breast milk is important. Therefore, in the present study, lead (Pb), cadmium (Cd), nickel (Ni), and arsenic (As) levels were measured by atomic absorption spectrometry in 64 breast milk samples obtained from mothers from Ankara, Turkey. Pb and Ni levels in breast milk samples were found to be 391.45?±?269.01?μg/l and 43.94?±?33.82?μg/l (mean ± SD), respectively. Cd was found only in one of 64 samples, and the level was 4.62?μg/l. As level was below the limit of quantification (LOQ, 7.6?μg/l) in all samples. These findings will accurately direct strategies and solutions of protection against contaminants in order to reduce their levels in biological fluids.     

Overexpression of high molecular weight FGF-2 forms inhibits glioma growth by acting on cell-cycle progression and protein translation

In order to clarify the role of HMW FGF-2 in glioma development and angiogenesis, we over-expressed different human FGF-2 isoforms in C6 rat glioma cell line using a tetracycline-regulated expression system. Phenotypic modifications were analyzed in vitro and compared to untransfected cells or to cells over-expressing 18 kDa FGF-2 or all FGF-2 isoforms. In particular, we demonstrate that HMW FGF-2 has unique features in inhibiting glioma cell proliferation. HMW FGF-2 expressing cells showed a cell-cycle arrest at the G2M, demonstrating a role of HMW FGF-2 in controlling the entry in mitosis. Moreover, hydroxyurea was ineffective in blocking cells at the G1S boundary when HMW FGF-2 was expressed. We also show that the HMW FGF-2 isoforms inhibit 4E-BP1 phosphorylation at critical sites restoring the translation inhibitory activity of 4E-BP1. In vivo, inhibition of tumor growth was observed when cells expressed HMW FGF-2. This indicates that HMW FGF-2 inhibits tumor growth in glioma cells by acting on cell-cycle progression and protein translation.     

Neural invasion in pancreatic cancer: a mutual tropism between neurons and cancer cells

Neural invasion by pancreatic cancer cells (PCC) worsens the prognosis and frequently limits curative resection. We established a novel in-vitro model in which T3M4-PCCs were co-cultured with either isolated myenteric plexus cells (MP) or dorsal root ganglia (DRG) of newborn rats within a three-dimensional extracellular matrix gel. The close vicinity of MP or DRG to T3M4-PCCs induced early morphologic changes on T3M4-PCCs at the migration front prior to the migration process with elongated and neurite-targeting PCCs, compared to round and non-grouping at the non-migrating front. T3M4-PCCs built cancer-cell clusters around the DRG or MP, a process which was accelerated by increasing number of T3M4-PCCs or neurons. These findings indicate that neuro-cancer interactions start prior to PCC migration and induce evident changes in cancer and nerve biology. These findings can be reproduced within the introduced 3D in-vitro migration assay which allows investigation in the early pathogenesis of neural PCC invasion.     

L-carnitine protects gastric mucosa by decreasing ischemia-reperfusion induced lipid peroxidation.

Studies have shown that reactive oxygen metabolites and lipid peroxidation play important roles in ischemia-reperfusion injury in many organs such as heart, brain and stomach. The aim of this study is to evaluate the antioxidant effect of L-carnitine on gastric mucosal barrier, lipid peroxidation and the activities of antioxidant enzymes in rat gastric mucosa subjected to ischemia-reperfusion injury. Rats were subjected to 30 min of ischemia followed by 60 min of reperfusion. L-carnitine (100 mg/kg), was given to rats intravenously five minutes before the ischemia. In our experiment, lesion index, thiobarbituric acid reactive substances, prostaglandin E2 and mucus content in gastric tissue were measured. The results indicated that the lesion index and the formation of thiobarbituric acid reactive substances increased significantly with the ischemia-reperfusion injury in the gastric mucosa. L-carnitine treatment reduced these parameters to the values of sham operated rats. The tissue catalase and superoxide dismutase activities and prostaglandin E2 production decreased significantly in the gastric mucosa of rats exposed to ischemia-reperfusion. L-carnitine pretreatment increased the tissue catalase activity and prostaglandin E2 to the levels of sham-operated rats but did not change superoxide dismutase activity. There were no significant difference in glutathione peroxidase activity and mucus content between the groups in the gastric mucosa. In summary, L-carnitine pretreatment protected gastric mucosa from ischemia-reperfusion injury by its decreasing effect on lipid peroxidation and by preventing the decrease in prostaglandin E2 content of gastric mucosa.