The molecular basis of water transport in the brain

Brain function is inextricably coupled to water homeostasis. The fact that most of the volume between neurons is occupied by glial cells, leaving only a narrow extracellular space, represents an important challenge, as even small extracellular volume changes will affect ion concentrations and therefore neuronal excitability. Further, the ionic transmembrane shifts that are required to maintain ion homeostasis during neuronal activity must be accompanied by water. It follows that the mechanisms for water transport across plasma membranes must have a central part in brain physiology. These mechanisms are also likely to be of pathophysiological importance in brain oedema, which represents a net accumulation of water in brain tissue. Recent studies have shed light on the molecular basis for brain water transport and have identified a class of specialized water channels in the brain that might be crucial to the physiological and pathophysiological handling of water.     

Mechanisms of maternal aneuploidy: FISH analysis of oocytes and polar bodies in patients undergoing assisted conception

We have examined unfertilised oocytes and their first polar bodies (PBs) to determine the way in which the frequency of whole chromosome imbalance compares with that involving single chromatids and whether the precocious separation of chromatids prior to anaphase I affects all pairs of chromosomes. We have applied the technique of fluorescent in situ hybridisation in a three-stage method by using locus-specific probes for chromosomes 13 and 21 and alpha-satellite probes for chromosomes 1, 9, 16, 18 and X to determine the chromosome status of oocytes and their PBs. We obtained analysable results from 127 oocytes and 57 PBs from 72 patients of average age 33 years. Six oocytes and three PBs had extra signals but, of these, three were derived from a single patient, aged 26. Anomalies were seen in chromosomes 13, 16, 18, X and, notably, 21 but none were observed in chromosomes 1 and 9. Half of the anomalies involved additional chromatids rather than whole chromosomes. Since particular chromatids were found to be prematurely separated in the metaphase II oocyte, this may provide further evidence for an additional mechanism of maternal aneuploidy that operates at anaphase II. Detailed analyses of both oocytes and PBs have elucidated possible mechanisms leading to aneuploid gametes in this group of patients with fertility problems.     

Evidence on the presence of two distinct alkaline phosphatases in Serratia marcescens

Certain strains of Serratia marcescens synthesized two different types of alkaline phosphatase (APase), constitutive (CAPase) and inducible (IAPase) APases, in low phosphate medium. Synthesis of the IAPase was repressed in the presence of high phosphate. Purification and separation of these electrophoretically distinct APases was achieved by using fractional (NH(4))(2)SO(4) precipitation, adsorption on a DEAE-cellulose column and elution of enzymes by a linear sodium chloride gradient. Starch gel electrophoresis of certain fractions revealed the separation of not only IAPase from CAPase but its separation into four distinct isozymes. CAPase gave maximum enzyme activity around pH 9.5, whereas for IAPase a broad range of enzyme activity was found between pH 8.5 and 10.5. Reversible inactivation at low pH occurred for IAPase but very little with CAPase. CAPase was more thermolabile than IAPase at 95 degrees C. The two APases were found to be distinct in their kinetic as well as immunological properties, suggesting two distinct enzyme species.     

Adaptive response to low dose of EMS or MMS in human peripheral blood lymphocytes

Human peripheral blood lymphocytes stimulated in vitro for 6 hr were exposed to a low (conditioning) dose of ethyl methanesulfonate (EMS; 1.5 x 10(-4) M) or methyl methanesulfonate (MMS; 1.5 x 10(-5) M). After 6 hr, the cells were treated with a high (challenging) concentration of the same agent (1.5 x 10(-3) M EMS or 1.5 x 10(-4) M MMS). The cells that received both conditioning and challenging doses became less sensitive to the induction of sister chromatid exchanges (SCEs) than those which did not receive the pretreatment with EMS or MMS. They responded with lower frequencies of SCEs. This suggests that conditioning dose of EMS or MMS has offered the lymphocytes to have decreased SCEs. This led to the realization that pre-exposure of lymphocytes to low dose can cause the induction of repair activity. This is a clear indication of the existence of adaptive response induced by alkylating agents whether it is ethylating or methylating in human lymphocytes in vitro.     

Partial purification and kinetic properties of three different d-glucosamine 6-P:N-acetyltransferase forms from human placenta

Three distinct forms of -glucosamine 6-P (Gm 6-P):N-acetyltransferases (EC 2.3.1.4) were partially purified from human placental homogenates by carboxy methyl-Sephadex chromatography. Purification of forms I and II were 13.5-fold, while that of form III was 114-fold. All three forms had a pH optimum value of 9.7 in glycine–NaOH buffer. Enzymes II and III had a K_m value for Gm 6-P of 3.0 mM, which was less than half of that observed for form I (7.1 mM). The corresponding K_m values for acetyl CoA were 0.157 (form I), 0.187 (form II) and 0.280 mM (form III), respectively. Activities of all three forms were inhibited at high concentrations of either substrate. These enzymes were inhibited from 82 to 92% by 2.5 mM p-chloromercuribenzoate. The inhibition was largely reversible by inclusion of 2.5 mM dithiothreitol in the incubation mixtures. There was no requirement for divalent cations, as demonstrated by lack of inhibition of enzyme activity by ethylene diamine tetraacetate. The results are discussed in terms of differences among the enzyme properties of human placental, rodent and porcine liver forms.     

16.1% Efficient Hysteresis‐Free Mesostructured Perovskite Solar Cells Based on Synergistically Improved ZnO Nanorod Arrays

Significant efficiency improvements are reported in mesoscopic perovskite solar cells based on the development of a low‐temperature solution‐processed ZnO nanorod (NR) array exhibiting higher NR aspect ratio, enhanced electron density, and substantially reduced work function than conventional ZnO NRs. These features synergistically result in hysteresis‐free, scan‐independent, and stabilized devices with an efficiency of 16.1%. Electron‐rich, nitrogen‐doped ZnO (N:ZnO) NR‐based electron transporting materials (ETMs) with enhanced electron mobility produced using ammonium acetate show consistently higher efficiencies by one to three power points than undoped ZnO NRs. Additionally, the preferential electrostatic interaction between the ­nonpolar facets of N:ZnO and the conjugated polyelectrolyte polyethylenimine (PEI) has been relied on to promote the hydrothermal growth of high aspect ratio NR arrays and substantially improve the infiltration of the perovskite light absorber into the ETM. Using the same interactions, a conformal PEI coating on the electron‐rich high aspect ratio N:ZnO NR arrays is ­successfully applied, resulting in a favorable work function shift and altogether leading to the significant boost in efficiency from <10% up to >16%. These results largely surpass the state‐of‐the‐art PCE of ZnO‐based perovskite solar cells and highlight the benefits of synergistically combining mesoscale control with doping and surface modification.     

Steroidal dihydrocarbothioic acid amido pyrazoles: synthesis,characterization, cytotoxicity and genotoxicity studies

A new series of steroidal dihydrocarbothioic acid amido pyrazole analogues were synthesized, and after characterization, evaluation for cytotoxicity, comet assay and western blotting was carried out. The synthesis of these analogues is convenient and involves two steps, i.e. aldol condensation as first step followed by nucleophilic addition of thiosemicarbazide across α, β-unsaturated carbonyl as a later step. Quantitative yields of more than 80 % are obtained in both the steps. After characterization by IR, ¹H NMR, ¹³C NMR, MS and analytical data, all the compounds of both series were tested for cytotoxic activity against a panel of different human cancer cell lines by MTT assay, during which compound 3e, 3f, 4e, 4f and 4h are very potent especially against HepG2 and MCF-7 cancer cell lines. Cell cycle analysis depicted the cell death in S-phase while as annexin V-FITC/PI analysis showed that compounds effectively induce apoptosis. Apoptotic degradation of DNA of MCF-7 cells in the presence of different steroidal derivatives was analysed by agarose gel electrophoresis and visualized by ethidium bromide staining (comet assay). In western blotting analysis, the relative expressions of relevant apoptotic markers depicted an apoptosis by steroidal dihydropyrazole in MCF-7 cancer cells.     

APOA2 ?256T>C polymorphism interacts with saturated fatty acids intake to affect anthropometric and hormonal variables in type 2 diabetic patients

Recent studies have established the interaction between APOA2 −256T>C polymorphism and dietary saturated fatty acids intake in relation to obesity on healthy individuals. In the current study, we investigate the effects of this interaction on anthropometric variables and serum levels of leptin and ghrelin in patients with type 2 diabetes. In this cross-sectional study, 737 patients with type 2 diabetes mellitus (290 males and 447 females) were recruited from diabetes clinics in Tehran. The usual dietary intake of all participants during the last year was obtained by validated semiquantitative food frequency questionnaire. APOA2 genotyping was performed by real-time PCR on genomic DNA. No significant relation was obtained by univariate analysis between anthropometric variables and APOA2 genotypes. However, after adjusting for age, gender, physical activity and total energy intake, we identified a significant interaction between APOA2-saturated fatty acids intake and body mass index (BMI). After adjusting for potential confounders, serum levels of ghrelin in CC genotype patients were significantly higher than T allele carriers (p = 0.03), whereas the case with leptin did not reveal a significant difference. The result of this study confirmed the interaction between APOA2 −256T>C polymorphism and SFAs intake with BMI in type 2 diabetic patients. In fact, homozygous patients for the C allele with high saturated fatty acids intake had higher BMI. The APOA2 −256T>C polymorphism was associated with elevated levels of serum ghrelin.     

Antisecretory,Gastroprotective, Antioxidant and Anti-Helicobcter Pylori Activity of Zerumbone from Zingiber Zerumbet (L.) Smith

Background

Zingiber zerumbet Smith is a perennial herb, broadly distributed in many tropical areas. In Malaysia, it’s locally known among the Malay people as “lempoyang” and its rhizomes, particularly, is widely used in traditional medicine for the treatment of peptic ulcer disease beyond other gastric disorders.

Aim of the study

The aim of the current study is to evaluate the gastroprotective effect of zerumbone, the main bioactive compound of Zingiber zerumbet rhizome, against ethanol-induced gastric ulcer model in rats.

Materials and Methods

Rats were pre-treated with zerumbone and subsequently exposed to acute gastric ulcer induced by absolute ethanol administration. Following treatment, gastric juice acidity, ulcer index, mucus content, histological analysis (HE and PAS), immunohistochemical localization for HSP-70, prostaglandin E2 synthesis (PGE₂), non-protein sulfhydryl gastric content (NP-SH), reduced glutathione level (GSH), and malondialdehyde level (MDA) were evaluated in ethanol-induced ulcer in vivo. Ferric reducing antioxidant power assay (FRAP) and anti-H. pylori activity were investigated in vitro.

Results

The results showed that the intragastric administration of zerumbone protected the gastric mucosa from the aggressive effect of ethanol-induced gastric ulcer, coincided with reduced submucosal edema and leukocyte infiltration. This observed gastroprotective effect of zerumbone was accompanied with a significant (p <0.05) effect of the compound to restore the lowered NP-SH and GSH levels, and to reduce the elevated MDA level into the gastric homogenate. Moreover, the compound induced HSP-70 up-regulation into the gastric tissue. Furthermore, zerumbone significantly (p <0.05) enhanced mucus production, showed intense PAS stain and maintained PG content near to the normal level. The compound exhibited antisecretory activity and an interesting minimum inhibitory concentration (MIC) against H. pylori strain.

Conclusion

The results of the present study revealed that zerumbone promotes ulcer protection, which might be attributed to the maintenance of mucus integrity, antioxidant activity, and HSP-70 induction. Zerumbone also exhibited antibacterial action against H. pylori.