Association of Maternal Vitamin D Status with Glucose Tolerance and Caesarean Section in a Multi-Ethnic Asian Cohort: The Growing Up in Singapore Towards Healthy Outcomes Study

Objective

Epidemiological studies relating maternal 25-hydroxyvitamin D (25OHD) with gestational diabetes mellitus (GDM) and mode of delivery have shown controversial results. We examined if maternal 25OHD status was associated with plasma glucose concentrations, risks of GDM and caesarean section in the Growing Up in Singapore Towards healthy Outcomes (GUSTO) study.

Methods

Plasma 25OHD concentrations, fasting glucose (FG) and 2-hour postprandial glucose (2HPPG) concentrations were measured in 940 women from a Singapore mother-offspring cohort study at 26–28 weeks’ gestation. 25OHD inadequacy and adequacy were defined based on concentrations of 25OHD ≤75nmol/l and >75nmol/l respectively. Mode of delivery was obtained from hospital records. Multiple linear regression was performed to examine the association between 25OHD status and glucose concentrations, while multiple logistic regression was performed to examine the association of 25OHD status with risks of GDM and caesarean section.

Results

In total, 388 (41.3%) women had 25OHD inadequacy. Of these, 131 (33.8%), 155 (39.9%) and 102 (26.3%) were Chinese, Malay and Indian respectively. After adjustment for confounders, maternal 25OHD inadequacy was associated with higher FG concentrations (β = 0.08mmol/l, 95% Confidence Interval (CI) = 0.01, 0.14), but not 2HPPG concentrations and risk of GDM. A trend between 25OHD inadequacy and higher likelihood of emergency caesarean section (Odds Ratio (OR) = 1.39, 95% CI = 0.95, 2.05) was observed. On stratification by ethnicity, the association with higher FG concentrations was significant in Malay women (β = 0.19mmol/l, 95% CI = 0.04, 0.33), while risk of emergency caesarean section was greater in Chinese (OR = 1.90, 95% CI = 1.06, 3.43) and Indian women (OR = 2.41, 95% CI = 1.01, 5.73).

Conclusions

25OHD inadequacy is prevalent in pregnant Singaporean women, particularly among the Malay and Indian women. This is associated with higher FG concentrations in Malay women, and increased risk of emergency caesarean section in Chinese and Indian women.     

A rare case of solution and solid state inter-conversion of two copper(II) dimers and a copper(II) chain

Three Cu(II)-azido complexes of formula [Cu₂L₂(N₃)₂] (1), [Cu₂L₂(N₃)₂]·H₂O (2) and [CuL(N₃)]_n (3) have been synthesized using the same tridentate Schiff base ligand HL (2-[(3-methylaminopropylimino)-methyl]-phenol), the condensation product of N-methyl-1,3-propanediamine and salicyldehyde). Compounds 1 and 2 are basal-apical μ-1,1 double azido bridged dimers. The dimeric structure of 1 is centrosymmetric but that of 2 is non-centrommetric. Compound 3 is a μ-1,1 single azido bridged 1D chain. The three complexes interconvert in solution and can be obtained in pure form by carefully controlling the synthetic conditions. Compound 2 undergoes an irreversible transformation to 1 upon dehydration in the solid state. The magnetic properties of compounds 1 and 2 show the presence of weak antiferromagnetic exchange interactions mediated by the double 1,1-N₃ azido bridges (J = −2.59(4) and −0.10(1) cm−¹, respectively). The single 1,1-N₃ bridge in compound 3 mediates a negligible exchange interaction.     

Indomethacin inactivates gastric peroxidase to induce reactive-oxygen-mediated gastric mucosal injury and curcumin protects it by preventing peroxidase inactivation and scavenging reactive oxygen

We have investigated the mechanism of indomethacin-induced gastric ulcer caused by reactive oxygen species (ROS) and the gastroprotective effect of curcumin thereon. Curcumin dose-dependently blocks indomethacin-induced gastric lesions, showing 82% protection at 25 mg/kg. Indomethacin-induced oxidative damage by ROS as shown by increased lipid peroxidation and thiol depletion is almost completely blocked by curcumin. Indomethacin causes nearly fivefold increase in hydroxyl radical (()OH) and significant inactivation of gastric mucosal peroxidase to elevate endogenous H(2)O(2) and H(2)O(2)-derived ()OH, which is prevented by curcumin. In vitro studies indicate that indomethacin inactivates peroxidase irreversibly only in presence of H(2)O(2) by acting as a suicidal substrate. 5,5-Dimethyl-pyrroline-N-oxide (DMPO) protects the peroxidase, indicating involvement of indomethacin radical in the inactivation. Indomethacin radical was also detected in the peroxidase-indomethacin-H(2)O(2) system as DMPO adduct (a(N) = 15 G, a(beta)(H) = 16 G) by electron spin resonance spectroscopy. Curcumin protects the peroxidase in a concentration-dependent manner and consumes H(2)O(2) for its oxidation as a suitable substrate of the peroxidase, thereby blocking indomethacin oxidation. Curcumin can also scavenge ()OH in vitro. We suggest that curcumin protects gastric damage by efficient removal of H(2)O(2) and H(2)O(2) -derived ()OH by preventing peroxidase inactivation by indomethacin.     

Environmental Sensing and Signal Transduction Pathways Regulating Morphopathogenic Determinants of Candida albicans

Candida albicans is an opportunistic fungal pathogen that is found in the normal gastrointestinal flora of most healthy humans. However, under certain environmental conditions, it can become a life-threatening pathogen. The shift from commensal organism to pathogen is often correlated with the capacity to undergo morphogenesis. Indeed, under certain conditions, including growth at ambient temperature, the presence of serum or N-acetylglucosamine, neutral pH, and nutrient starvation, C. albicans can undergo reversible transitions from the yeast form to the mycelial form. This morphological plasticity reflects the interplay of various signal transduction pathways, either stimulating or repressing hyphal formation. In this review, we provide an overview of the different sensing and signaling pathways involved in the morphogenesis and pathogenesis of C. albicans. Where appropriate, we compare the analogous pathways/genes in Saccharomyces cerevisiae in an attempt to highlight the evolution of the different components of the two organisms. The downstream components of these pathways, some of which may be interesting antifungal targets, are also discussed.     

Need for Revisiting the Use of Magnetic Oxides as Electrode Materials in Supercapacitors: Unequivocal Evidence of Significant Variation in Specific Capacitance under Variable Magnetic Field

A simple question, which remains ignored in the field of supercapacitors is: will the device performance be affected near a magnetic field, if it is fabricated using electrode materials that are also magnetic? It is shown in this paper that the answer is: yes, it will be appreciably affected! The modulation in the specific capacitance is a convoluted picture of variation: diffusion mechanics of solvated cations, Nernst layer at the interface, magnetoresistance, and associated I–V response. The magnetic field also has direct control on the value at which saturation in specific capacitance is observed in such devices. Nearly a 170% increase in energy density at 1 A g^?1 is observed by varying the magnetic field from 0 to 5 mT and a ten fold increase in power density is observed at 5 mT when current density is increased from 1 to 5 A g^?1. These results clearly show that electronic circuitry designed using supercapacitors needs to be reworked/designed if it is to be used in or around magnetic environment. To prove the concept and have a complete picture in one article, the paper presents results on nanosized magnetic metal oxides based on the four ferromagnetic elements, Fe, Co, Mn, and Ni.     

DNA interactive property of poly-L-lysine induces apoptosis in MCF-7 cells through DNA interaction

Poly-L-lysine (PLL) is known to be an encapsulating agent in drug formulation and delivery. PLL also has apoptotic and antiproliferative activities that enable blocking of the tumorigenesis process. However, the dose-selective activities of PLL in exerting apoptosis against cancer are unclear. Therefore, this study has been designed to explore the potential role and dose of PLL in apoptosis, if any. For this, PLL was administered at several doses in cancer cell lines and was found to be more potent against MCF-7 cells. PLL causes mitochondria-mediated apoptotic death through the upregulation of cleaved caspase-3. To investigate the mechanism responsible for this activity, we have analyzed if PLL could have the DNA interactive property or not. For this, molecular docking analysis was carried out to prove whether it has the property to bind with DNA or not. Studies have revealed that PLL is a potent DNA binder and it probably performs such apoptotic activities through the binding of cellular DNA early in an exposure. Simultaneous upregulation of both ROS-mediated stress and also in key protein expressions like γ-H2AX could also help us to confirm that PLL induces apoptosis through DNA interaction. This finding leads us to believe that PLL could play an interfering role with other chemotherapeutic compounds when used as a drug-coating material as it exerts an apoptotic effect on cancer cells, which should be avoided by using a much lower concentration.