Investigation of the protective effect of chitosan against arsenic-induced nephrotoxicity and oxidative damage in rat kidney tissue

Arsenic is an important metalloid that can cause poisoning in humans and domestic animals. Exposure to arsenic causes cell damage, increasing the production of reactive oxygen species. Chitosan is a biopolymer obtained by deacetylation of chitin with antioxidant and metal ion chelating properties. In this study, the protective effect of chitosan on arsenic-induced nephrotoxicity and oxidative damage was investigated. 32 male Wistar-albino rats were divided into 4 groups of 8 rats each as control group (C), chitosan group (CS group), arsenic group (AS group), and arsenic+chitosan group (AS+CS group). The C group was given distilled water by oral gavage, the AS group was given 100 ppm/day Na-arsenite ad libitum with drinking water, the CS group was given 200 mg/kg/day chitosan dissolved in saline by oral gavage, the AS+CS group was given 100 ppm/day Na-arsenite ad libitum with drinking water and 200 mg/kg/day chitosan dissolved in saline by oral gavage for 30 days. At the end of the 30-day experimental period, 90 mg/kg ketamine was administered intraperitoneally to all rats, and blood samples and kidney tissues were collected. Urea, uric acid, creatinine, P, Mg, K, Ca, Na, Cystatin C (CYS-C), Neutrophil Gelatinase Associated Lipocalin (NGAL) and Kidney Injury Molecule 1 (KIM-1) levels were measured in serum samples. Malondialdehyde (MDA), Glutathione (GSH), Catalase (CAT) and Superoxide dismutase (SOD) levels in the supernatant obtained from kidney tissue were analyzed by ELISA method. Compared with AS group, uric acid and creatinine levels of the AS+CS group were significantly decreased (p<0.001), urea, KIM-1, CYS-C, NGAL, and MDA levels were numerically decreased and CAT, GSH, and SOD levels were numerically increased (p>0.05). In conclusion, based on both biochemical and histopathological-immunohistochemical- immunofluorescence findings, it can be concluded that chitosan attenuates kidney injury and protects the kidney.

MXene-based Ti2C/Ta2C lateral heterostructure: an intrinsic room temperature ferromagnetic material with large magnetic anisotropy

Two-dimensional (2D) lateral heterostructures (LH) combining Ti₂C and Ta₂C MXenes were investigated by means of first-principles calculations. Our structural and elastic properties calculations show that the lateral Ti₂C/Ta₂C heterostructure results in a 2D material that is stronger than the original isolated MXenes and other 2D monolayers such as germanene or MoS₂. The analysis of the evolution of the charge distribution with the size of the LH shows that, for small systems, it tends to distribute homogeneously between the two monolayers, whereas for larger systems electrons tend to accumulate in a region of ∼6 Å around the interface. The work function of the heterostructure, one crucial parameter in the design of electronic nanodevices, is found to be lower than that of some conventional 2D LH. Remarkably, all the heterostructures studied show a very high Curie temperature (between 696 K and 1082 K), high magnetic moments and high magnetic anisotropy energies. These features make (Ti₂C)/(Ta₂C) lateral heterostructures very suitable candidates for spintronic, photocatalysis, and data storage applications based upon 2D magnetic materials.

Exploring a novel class of Janus MXenes by first principles calculations: structural, electronic and magnetic properties of Sc2CXT, X = O, F, OH; T = C, S, N

The already intriguing electronic and optical properties of the MXene Sc₂C family can be further tuned through a wide range of possible functionalizations. Here, by means of density functional theory, we show that the 36 possible elements of the Janus MXT (M: Sc₂C, X: O, F, OH, T: C, N, S) family, built by considering the four possible structural models (i) FCC, (ii) HCP, (iii) FCC + HCP, and (iv) HCP + FCC, are all potentially stable. The analysis of their mechanical properties shows the excellent mechanical flexibility of functionalized MXenes (f-MXenes) under large strain, making them more suitable for applications where stress could be an issue. Interestingly, while Sc₂C presents a metallic character, Sc₂COS, Sc₂CFN and Sc₂COHN are found to be semiconductors with bandgaps of 2.5 eV (indirect), 1.67 eV (indirect) and 1.1 eV (direct), respectively, which presents promising applications for nano- and optoelectronics. Moreover, Sc₂CFC presents a ferromagnetic ground state with the 2 × 2 × 1 supercell magnetic moment of 3.99 μ_B, while the ground state of Sc₂COHC might be antiferromagnetic with a magnetic moment of 3.98 μ_B, depending on the environment. Remarkably, the band structures of Sc₂CFC and Sc₂COHC present a half-metallic character with an HSE06 fundamental band gap of 0.60 eV and 0.48 eV, respectively. Our results confirm the extraordinary potential of the Janus MXT (M: Sc₂C, X: O, F, OH, T: C, N, S) family for novel applications in 2D nano-,opto- and spintronics.

Alkali-based pre-treatment may prevent ochratoxin A in grapes

In traditional raisin production process in Turkey, one of the major raisin producers in the world, grapes undergo an alkali treatment prior to drying. This procedure involves dipping grapes in a potassium carbonate solution for 10-15 seconds to remove the wax layer on the surface to accelerate the drying process. In this study, we aimed to investigate the effect of alkali treatment on ochratoxin A (OTA), an important risk factor for grapes and grape-derived products. First, the stability of the OTA was examined under variable pH (4-12), ion type (Na+, K+), ionic strength (0.1-10%) and temperature (4-60 °C). Then, Aspergillus ochraceus contaminated grapes were treated with an alkaline solution and a subsequent OTA analysis was performed through a high performance liquid chromatography-fluorescence detection. OTA started to decompose at pH values exceeding 10.0. The degradation followed a first order kinetics. Although both sodium carbonate and potassium carbonate solutions were at the same alkali pH and they both triggered the OTA degradation at increasing concentrations, potassium carbonate was more effective even at low concentrations. Elevated temperatures were also found to effect degradation. The degradation rate constant at 40 °C was approximately 5 times greater than the one at 25 °C. Furthermore, OTA levels dropped up to 50% in contaminated grapes after the alkali treatment. Our results confirmed that the amide bond of OTA rapidly hydrolysed to a non-toxic ochratoxin-alpha and phenylalanine under strong alkaline conditions. The results suggest that the alkaline pre-treatment unintentionally offers a great advantage to reduce OTA levels in raisins and it could be a viable approach for other dried fruits through the application of good manufacturing practice.

Serum estradiol/free testosterone ratio can be important predictor for varicose vein recurrence in men

AIM

Recurrent varicose veins are a frustration for both the patient and the surgeon. More investigation of the exact diagnosis, proper practice, and causes for the recurrence of varicose veins is needed.

METHODS

We investigated a total number of 187 patients in a five year period with an estradiol-2/free testosterone (E2/fT) ratio relationship on recurrent varicose veins in men between the ages of 20-50. Fifity years was the maximum age due to the age dependent sex steroid hormone regression that occurs after this age, which may interefere with the assessment. Fifty three men with an elevated E2/fT ratio (group A), and 143 men with no endocrinologic problems (group B) were enrolled in the study and had surgery for varicose veins. After 5 years follow up (mean 3 years), Group A (N.=29) and group B (N.=43) had recurrent varicose veins by clinical and radiologic findings. Venous blood samples were driven from all patients of both groups in the morning to detect the levels of serum E2 and fT levels. Patient history of surgery for varicose veins, physical examination, color duplex ultrasound of both limbs, and classification of CEAP were performed in both groups.

RESULTS

The serum E2/fT ratio was significantly higher in Group A (5.21 ± 0.56) compared to group B (2.54±0.27) in the recurrent varicose vein groups (p ≤ 0.05). Moreover, there was a high correlation between serum E2/fT ratio and the CEAP clinical classification in group A (5) compared to group B (2) (P≤0.05). Also, recurrence rate was higher in group A (54%) compared to group B (32%)(P≤0.05).

CONCLUSION

Elevated serum E2/fT ratio is a precipitating factor for recurrent varicose veins in male patients.

Multiple repeat cesarean delivery is associated with increased maternal morbidity irrespective of placenta accreata

OBJECTIVE

The present study aimed to investigate the perinatal morbidity associated with multiple repeat cesarean deliveries (CD) and, thus, to achieve a body of evidence for the current practice of discouraging pregnancy after undergoing three CDs.

PATIENTS AND METHODS

This study prospectively reviewed a total of 500 women who consecutively underwent CD between January 1, 2009 and April 1, 2009. The patients were allocated into four groups based on the number of CDs they had undergone (Group 1: first CD, Group 2: second CD, Group 3: third CD, Group 4: fourth CD). Data related with their demographic and clinical characteristics were recorded as well as their perioperative characteristics and clinical characteristics of the neonates born to them. Cochran-Armitage test for trends and Spearman rank correlation analysis test was used to evaluate the trend of perioperative complications and neonatal outcome with the increasing number of CDs.

RESULTS

The mean age, gravidity and parity were significantly higher in groups 2-4 than those of the women who had their first CD (Group 1). The average operation time and mean delivery time as well as severe adhesions, bowel injury increased significantly with the number of CD. Neonatal characteristics were similar among groups except for a trend towards a decrease in the rate of meconium stained and a trend towards increase in the rate of neonatal sepsis with the increasing number of CD.

CONCLUSIONS

We have found positive correlation between the maternal morbidity and the number of CDs. The occurrence of adhesions emerges as the most significant indicator of maternal morbidity, eventually leading to the neighboring organ injury and prolonged operation time.

Rapid LC and LC/MS for routine analysis of mycotoxins in foods

Affinity column clean-up of food samples for mycotoxin analysis produces extracts which are free of co-extractives and therefore require little chromatography for separation and quantification of the target analytes. Using such clean extracts, we report rapid chromatographic methods for aflatoxins B1, B2, G1 and G2, aflatoxin M1, ochratoxin A, zearalenone and fumonisins. Using short columns with small particle size packing, HPLC conditions have been developed reducing analysis time typically by 75%, e.g. for aflatoxins from 19.0 min to 4.0 min with full separation of the four toxins and for aflatoxin M1 giving an analysis time of less than 1 min compared to 5 min for conventional analysis. Fumonisins were analysed directly by LC/MS in a run time of 4.1 min, using selected ion monitoring to avoid the need for derivatisation for fluorescence detection by HPLC. Peak purity under rapid analysis conditions has been demonstrated by LC/MS for a variety of food extracts such as pistachios, hazelnuts, paprika, cocoa, coffee, cereals, sesame oil, cheese, maize, animal feed, dried figs, dried vine fruits, cornflakes and bread. These substantial reductions in analysis time offer significant benefits to laboratories undertaking routine screening and quantitative analysis of mycotoxins in foods.

Occurrence of fungi and their mycotoxins in individual Turkish dried figs

Fifty individual figs which had been rejected as potentially contaminated by sorting under UV light were separately analysed to identify the presence of fungi and their mycotoxins. Aflatoxin B1 was found in 49 samples with levels ranging from 0.7 to 222 ng g-1, with 40 individual figs containing more than 2 ng g-1, indicating the efficacy of the UV screening process in identifying contaminated fruit. Ochratoxin A (OTA) was found in 32 of the figs at levels from 0.4 to 1710 ng g-1, with 50% of the samples containing levels above 1 ng g-1. There was no evident correlation between levels of aflatoxin B1 and levels of OTA. Twenty fungal species were isolated from the outer and inner surfaces of the figs, some of which were subsequently cultured on YES and PDB and the media analysed for the presence of aflatoxin B1 and OTA to establish their toxigenicity.