Kainic acid-mediated increase of preprotachykinin-A messenger RNA expression in the rat hippocampus and a region-selective attenuation by dexamethasone.

The hippocampus contains the highest number of glucocorticoid-sensitive neurons in the rat brain and excessive exposure to glucocorticoids can cause damage to hippocampal neurons and impair the capacity of the hippocampus to survive neuronal insults. In this study in situ hybridization combined with quantitative image analysis was used to study preprotachykinin-A mRNA levels after administration of a toxic dose of kainic acid in animals pretreated with glucocorticoids. Kainic acid was injected into dorsal hippocampus CA3 region in animals pretreated with the synthetic glucocorticoid receptor agonist dexamethasone and in control animals. Preprotachykinin-A mRNA was not detected in the hippocampus of untreated animals or in animals analysed 30 min after a kainic acid injection. However, 4 h after injection of kainic acid, the level of preprotachykinin-A mRNA increased to 20-times above the detection limit both in the dentate gyrus and the CA3 region of the hippocampus. Treatment of kainic acid-injected animals with dexamethasone 30 min before and 2 h after the injection attenuated the increase in the granule cells of the dentate gyrus by 50%. In contrast, dexamethasone pretreatment had no significant effect on the kainic acid-induced increase of preprotachykinin-A mRNA in pyramidal cells in regions CA3 or CA1. These results show that an excitatory stimulus within the hippocampus causes a substantial increase in the level of preprotachykinin-A mRNA in hippocampal granule and pyramidal cells and suggest that in granule cells of the dentate gyrus this increase can be modulated by glucocorticoids.     

Phagocytosis in the colonial ascidian Botryllus schlosseri

Phagocytosis by Botryllus schlosseri hemocytes in influenced by temperature, pH, concentration, and physicochemical properties of the test particles and requires Ca²⁺ or Mg²⁺ ions to occur. Phagocytes recognized glucosyl or mannosyl residues on the surface of yeast cells, and a respiratory burst is associated with phagocytosis, as indicated by increased superoxide production. Factors that enhance phagocytosis of yeast, sheep red blood cells, and latex beads and reduce the uptake of yeast and sheep erythrocytes are present in the plasma.     

Influence of smoking habit on the frequency of micronuclei in human lymphocytes by the cytokinesis block method

To evaluate the frequency of micronucleated lymphocytes in a normal population, 45 healthy subjects were analysed by using a modified cytochalasin B block method; the influence of some confounding factors (sex, age, smoking, etc.) were taken into account. Using a stepwise regression test smoking habits were found to have a statistically significant influence on the frequency of micronucleated cells and micronuclei. In addition, the mitotic and proliferative indexes, and the frequency of micronucleated lymphocytes, at different culture times, were studied in four healthy subjects. Based on the results we suggest that cytochalasin B be added to cultures no later than the 42nd hour.     

Time in hemodialysis modulates the levels of genetic damage in hemodialysis patients

It is assumed that hemodialysis treatment can diminish the levels of genetic damage in circulating lymphocytes by cleaning the blood of uremic toxins that cause oxidative stress. However, the hemodialysis process by itself may also induce genomic damage by producing reactive oxygen species (ROS). We conducted a follow‐up study in a group of 70 hemodialysis patients followed for a mean time of 15 months. We investigated the effect of exposure time in hemodialysis on the levels of genetic damage in peripheral blood lymphocytes using the micronucleus assay. In addition, genetic damage after in vitro irradiation with 0.5 Gy was also analyzed to evaluate changes in radiosensitivity. Our results showed that, at the end of the study, there was a decrease in both the basal levels of genetic damage (9.9 ± 1.0 vs. 7.6 ± 0.7) and radiosensitivity values (38.5 ± 3.0 vs. 27.6 ± 2.4). We conclude that hemodialysis procedures may act as an ameliorating factor reducing the genetic damage present in chronic kidney disease patients. Environ. Mol. Mutagen. 55:363–368, 2014. © 2014 Wiley Periodicals, Inc.     

Genomic damage as a biomarker of chronic kidney disease status

Patients suffering from chronic kidney disease (CKD) exhibit a high incidence of cancer and cardiovascular diseases, as well as high levels of genomic damage. To confirm the association of CKD with genomic damage we have carried out the largest study to date addressing this issue, using a total of 602 subjects (187 controls, 206 pre‐dialysis CKD patients and 209 CKD patients in hemodialysis). DNA oxidative damage was measured in all individuals using the comet assay. Our results indicate that CKD patients have significantly higher levels of DNA damage than controls, but no significant differences were observed between pre‐hemodialysis (pre‐HD) and hemodialysis (HD) patients. When oxidative damage was measured, no differences were observed between patients and controls, although HD patients showed significantly higher levels of oxidative damage than pre‐HD patients. In addition, a positive relationship was demonstrated between genomic damage and all‐cause mortality. Our study confirms that genomic damage can be predictive of prognosis in CKD patients, with high levels of DNA damage indicating a poor prognosis in HD patients. Environ. Mol. Mutagen. 56:301–312, 2015. © 2014 Wiley Periodicals, Inc.     

Serum pepsinogen I elevation in cigarette smokers

We measured serum pepsinogen I (sPG-I) in 269 patients undergoing upper GI endoscopy and then classified by endoscopic diagnosis, gastric mucosal histology, and smoking habit. Both ulcer-free and duodenal ulcer smokers had significantly higher sPG-I levels than their non-smoking controls. In contrast, sPG-I values were not different in smokers and non-smokers with gastric ulcer. In ulcer-free smokers the overall increase in sPG-I simply reflected the high prevalence of patients with superficial gastritis and elevated sPG-I levels. Conversely, in duodenal ulcer smokers the increase in sPG-I, which was related to the number of cigarettes smoked daily, was not an epiphenomenon of concomitant gastritis. The smoking-induced increase in sPG-I in duodenal ulcer is proposed to reflect an augmented pepsin secretory capacity, which can be of aetiologic significance in the association between cigarette smoking and duodenal ulcer.     

A Cu(ii)-MOF based on a propargyl carbamate-functionalized isophthalate ligand

A copper-based metal–organic framework (MOF) was prepared using a new linker, a 5-substituted isophthalic acid bearing a propargyl carbamate group, intended to provide a terminal alkyne function protruding from the material surface to generate supported gold species for potential catalytic applications. The novel material was fully characterized by spectroscopic analyses of different kinds: FTIR, Raman, EDX, and XPS, as well as by thermal and surface area measurements. Synchrotron X-ray diffraction data analysis, in particular, revealed that this MOF, labelled [Cu(1,3-YBDC)]·xH₂O (x ∼ 2), where Y stands for the pendant alkYne and BDC for benzene dicarboxylate, contains a complex network of 5-substituted isophthalate anions bound to Cu(ii) centers, arranged in pairs within paddlewheel (or “Chinese lantern”) fragments of Cu₂(μ-COO)₄(D)₂ formulation (D being a neutral Lewis base), with a short Cu⋯Cu distance of 2.633(4) Å. Quite unexpectedly, the apical atom in the paddlewheel structure belongs to the carbamate carbonyl oxygen atom. Such extra coordination by the propargyl carbamate groups drastically reduces the MOF porosity, a feature that was also confirmed by BET measurements. However, the MOF functionality is retained at the external crystal surface where 2% of active terminal alkynes is located.

A copper-based metal–organic framework with a novel 5-substituted isophthalic linker bearing a propargyl carbamate group protruding from the material surface.