Antiangiogenic evaluation of ZnWO4 nanoparticles synthesised through microwave-assisted hydrothermal method

Angiogenesis, the complex process of formation of new blood vessels from pre-existing blood vessels, which involves the participation of several pro- and anti-angiogenic factors, is implicated in many physiological and pathological conditions. Nanoparticle-based anti-angiogenic activity at the tumour tissue, harnessed by the Enhanced Permeability and Retention Effect (EPR effect), could potentially become a breakthrough therapy to halt tumour progression. Herein, we evaluate the anti-angiogenic effect of ZnWO₄ nanoparticles (NPs). The nanoparticles were obtained by microwave-assisted hydrothermal synthesis (MAHS) at 120?°C for 60?min and were structurally characterised by X-ray diffraction (XRD) and micro-Raman (MR) spectroscopy. The mean size and polydispersity index were estimated by Zeta potential analysis. The XRD analysis revealed structural organisation at a long-range order, with an average crystallite size of around 3.67?nm, while MR revealed short-range order for ZnWO₄. The anti-angiogenic potential of zinc tungstate nanoparticles was investigated through the chorioallantoic membrane assay (CAM) using fertilised chicken eggs. We demonstrate, in an unprecedented way, that nanocrystalline ZnWO₄ NPs obtained by MAHS, at low reaction temperatures, showed excellent anti-angiogenic properties even at low concentrations. The ZnWO₄ NPs were further evaluated for its cytotoxicity in vitro.     

Expression and Prognostic Value of ZNRD1 in Esophageal Squamous Cell Carcinoma

The expression of ZNRD1 in esophageal cancer was first investigated by immunohistochemical analysis, RT-PCR and real-time PCR. The ZNRD1 antibody produced a consistently cytoplasmic staining pattern in all epithelial cells. The expression of ZNRD1 was statistically correlated with differentiation, depth of invasion, lymph node metastasis, pathological stage, lymphatic invasion, and vascular invasion. The survival rates of patients with ZNRD1-negative tumors tended to be statistically lower than those with ZNRD1-positive tumors. ZNRD1 expression was also confirmed to be down-regulated in esophageal cancer tissues compared to adjacent non-neoplastic tissues. The results showed that ZNRD1 might play an important role in esophageal carcinogenesis. Yunping Zhao and Liu Hong contributed equally to this study.     

Maternal experience prevents pup-killing in mice induced by peripheral anosmia

The ability of experience to modify pup-killing by a peripheral anosmia was investigated in a 2 × 2 design in which experience and anosmia were manipulated. Anosmia induced by zinc sulfate flush of the nasal epithelium resulted in pup-killing in 13 of 15 primiparous litters, whereas only 2 of 15 multiparous mothers were pup-killers. These results suggest that primiparous mothers depend heavily on olfaction and that a dichotomy exists between the peripheral chemical induced anosmia (modifiable by experience) and the central, whole bulb aspiration induced anosmia, not modifiable by experience.     

Learning and memory impairment in adult rats due to severe zinc deficiency during lactation

In a series of three experiments, adult rats who suffered severe zinc deficiency and/or undernutrition during lactation were tested in a 17-arm radial maze for working memory, reference memory, forgetting and learning. In Experiment 1, eight out of 17 arms were baited. The zinc deficient (ZD) and undernourished (PF) rats revealed a learning deficit when compared to adequately nourished rats (AL). ZD rats also appeared to display a loss of working memory. No evidence of loss of reference memory was observed among any of the groups. A reverse learning procedure was used in Experiment 2 to test the same rats used in Experiment 1. ZD rats were significantly inferior in performance of the reverse learning task compared to the AL and PF rats. No significant differences in performance were noted between the AL and PF rats. Although all groups displayed forgetfulness from Experiment 1 to Experiment 2, no significant differences in forgetfulness were evidenced among the groups. In Experiment 3, all 17 arms were baited. The ZD rats displayed a significant working memory deficit as compared to the AL and PF rats. No significant differences in working memory between the AL and PF rats occurred. The possibility that the differences in performance were due to differences in food motivation or attention was considered and rejected. It was concluded that ZD rats experienced a severe learning deficit and some working memory deficit while the PF rats experienced a mild learning deficit as compared to the AL rats.     

Effect of systemic zinc administration on delayed neuronal death in the gerbil hippocampus

The divalent cation zinc has been reported to possess several physiological properties such as blocking apoptotic cell death through an inhibitory effect on Ca²⁺-Mg²⁺ endonuclease activity, or modulating the neurotoxicity via glutamate receptor subtypes. In the present study, we investigated the effect of peripherally injected zinc on delayed neuronal death seen in the hippocampus after transient global ischemia, in order to elucidate a possible beneficial role on zinc in ischemic neuronal cell death. Forty-five adult Mongolian gerbils of both sexes underwent transient bilateral clipping of the common carotid arteries for 3 min. In the pretreated animals, ZnCl₂ (20 mg/kg) was injected subcutaneously once, 1 h before ischemia (superacute group; n=6) or twice at 24 and 48 h before ischemia (subacute group; n=14). Histological survey was carried out 3 days later by in situ DNA fragmentation method and 4 days later by hematoxylin-eosin staining by semiquantatively counting dead neurons in the CA1 sector. Subacute zinc pre-administration significantly reduced the nuclear damage and subsequent neuronal death; however, superacutely pre-administered zinc did not protect hippocampal neurons against ischemia but it did not aggravate the effect of ischemia, either. The present study suggested that transfer of exogenous zinc into the intracellular space is required for neuroprotection, presumably via the anti-endonuclease activity.     

Inhibition of NMDA-induced protein kinase C translocation by a Zn chelator: Implication of intracellular Zn

The role of intracellular Zn²⁺ in the translocation of protein kinase C from cytosol to membrane fractions was examined by the [³H]phorbol 12,13-dibutyrate (PDBu) binding method in guinea pig cerebral synaptoneurosomes. N-methyl-d-aspartate (NMDA, 100 μM) and calcium ionophore A23187 (0.3–30 μM) decreased the binding activity in the cytosol with a concomitant increase in the membrane fractions. Pretreatment of synaptoneurosomes with a heavy metal chelator, N,N,N′,N′-tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN), inhibited the NMDA- and A23187-induced changes of the distribution of [³H]PDBu binding sites in cytosol and membrane fractions. The inhibitory effect of TPEN was negated by a preincubation of TPEN with equimolar Zn²⁺ but not by that with Ca²⁺. The addition of 500 μM Zn²⁺ to the lysate of synaptoneurosomes induced an increase of [³H]PDBu binding activity in the membrane fraction with a concomitant decrease in the cytosol fraction, as did 100 μM Ca²⁺. Low concentrations of Zn²⁺ (10 μM), which alone had no effect on the distribution of the binding, significantly enhanced the effect of 10 μM Ca²⁺ in the lysate. Under those conditions TPEN inhibited the Zn²⁺-potentiated Ca²⁺-dependent changes in the binding. These results suggest that intracellular Zn²⁺ is essential for the agonist-induced translocation of protein kinase C in guinea pig synaptoneurosomes.     

Serum and hair zinc in severely malnourished Bangladeshi children associated with or without acute lower respiratory infection

Objective  To assess the zinc status in Bangladeshi children suffering from severe protein energy malnutrition (severe PEM), acute lower respiratory infection (ALRI), PEM presented with ALRI and to evaluate the relationship of zinc status with aforementioned clinical conditions. Methods  We assessed zinc status by simultaneous estimation of serum and hair zinc of Bangladeshi children less than 5 yr of age suffering from severe PEM, ALRI, severe PEM presented with ALRI and compared them with zinc status of well-nourished healthy children (control) in a hospital based cross sectional four cell study. Zinc concentration was estimated by Flame atomic absorption spectrophotometry. Results  Total one hundred and fifty two children were enrolled and number of children enrolled in severe PEM, ALRI, ALRI with PEM and control were 47, 35, 32 and 38 respectively. Both serum and hair zinc in univariate analysis were found significantly (p<0.05) low in severe PEM, ALRI and severe PEM associated with ALRI. However, in multivariate analysis, when serum and hair zinc were included in the same model, both serum and hair zinc were found to have significant negative association with PEM (p=0.002 & 0.013 respectively) and with ALRI only when ALRI was associated with PEM (p=0.043 and 0.034 respectively). Conclusion  Severe PEM and PEM with ALRI were significantly associated with low zinc status.     

Placental IGF-I, IGFBP-1, zinc, and iron, and maternal and infant anthropometry at birth

Aim: To correlate placental protein levels of insulin‐like growth factor (IGF)‐I and insulin‐like growth factor binding protein (IGFBP)‐1, with previously determined levels of IGF‐I and IGF‐II mRNA expression, and the micronutrients zinc and iron, and maternal and newborn anthropometry. Methods: Placental samples were collected from rural field sites in Pakistan. Samples were divided into small and large for gestational age groups (SGA and LGA, respectively). IGFBP‐1 levels were assessed using Western immunoblotting. IGF‐I protein levels were assessed using ELISA techniques. IGF mRNA expression, zinc, and iron, were quantified as previously described and were used for comparative purposes only. Results: Thirty‐three subjects were included (SGA, n = 12; LGA n = 21). Higher levels of IGFBP‐1 were seen in the SGA group (p < 0.01). IGFBP‐1 correlated positively with maternal and infant triceps skin‐fold thickness in the LGA and SGA groups, respectively (p < 0.05). Significantly lower IGF‐I protein levels were seen in the SGA group. IGF‐I levels correlated significantly with maternal and newborn anthropometry. IGFBP‐1 correlated significantly with IGF‐II mRNA expression (p < 0.05). Conclusion: Placental protein levels of IGF‐I and IGFBP‐1 appear to be associated with maternal anthropometry. Maternal anthropometry may thus influence IGFBP‐1 and IGF‐I levels and may possibly be used for screening of pregnancies, with the potential for timely identification of these high‐risk pregnancies.     

Enhanced zinc consumption causes memory deficits and increased brain levels of zinc

Zinc deficiency has been shown to impair cognitive functioning, but little work has been done on the effects of elevated zinc. This research examined the effect on memory of raising Sprague-Dawley rats on enhanced levels of zinc (10 ppm ZnCO3; 0.153 mM) in the drinking water for periods of 3 or 9 months, both pre- and postnatally. Controls were raised on lab water. Memory was tested in a series of Morris Water Maze (MWM) experiments, and zinc-treated rats were found to have impairments in both reference and working memory. They were significantly slower to find a stationary platform and showed greater thigmotaxicity, a measure of anxiety. On a working memory task, where the platform was moved each day, zinc-treated animals had longer latencies over both trials and days, swam further from the platform, and showed greater thigmotaxicity. On trials using an Atlantis platform, which remained in one place but was lowered on probe trials, the zinc-treated animals had significantly fewer platform crossings, spent less time in the target quadrant, and did not swim as close to the platform position. They had significantly greater latency on nonprobe trials. Microprobe synchrotron X-ray fluorescence (microSXRF) confirmed that brain zinc levels were increased by adding ZnCO3 to the drinking water. These data show that long-term dietary administration of zinc can lead to impairments in cognitive function.     

Zfp521在大鼠骨髓间充质干细胞向神经元分化过程中的表达变化及意义

目的: 探讨锌指蛋白521(Zfp521)在大鼠骨髓间充质干细胞分化为神经元过程中的表达变化及意义。方法: 体外培养大鼠MSCs,实验分为未转染组、转染组(转染Rn-Zfp521-siRNA)和阴性对照组(转染negative control siRNA),采用β-巯基乙醇诱导骨髓间充质干细胞分化为神经元。倒置荧光显微镜下观察MSCs转染后荧光表达情况。采用免疫细胞化学法、RT-PCR法及Western blotting法检测诱导后神经元特异性烯醇化酶(NSE)和微管相关蛋白2(MAP-2)的表达情况及诱导前、后Zfp521的表达变化。结果: (1)siRNA转染72 h荧光表达最强,转染率可达84.1%±2.3%,转染组骨髓间充质干细胞的Zfp521 mRNA表达下降(P<0.05);(2)β-巯基乙醇可以诱导骨髓间充质干细胞分化为神经元,以转染组诱导效果最佳,NSE和MAP-2表达显著高于其它各组(P<0.05);(3)Zfp521在各组细胞中均有表达,诱导后Zfp521表达明显低于诱导前(P<0.01)。结论: Zfp521在大鼠骨髓间充质干细胞神经分化中表达下降,抑制Zfp521表达可促进神经元的分化,提示Zfp521在骨髓间充质干细胞的神经分化中可能发挥重要调控作用。