Mohamed Ali Elsayed Khalifa

Reactions with heterocyclic β-enaminoesters: A novel synthesis of 2-amino-3-ethoxycarbonyl-(4H)-pyrans

The reaction of ethyl cyanoacetate with α-cyanochalcone (1) leads to the formation of β-enaminoesters (3) viaMichael addition. Compound3 reacts with phenylmagnesium bromide to give the β-enaminoketone5. Acetylation of3 gives the acetyl product4. Each of compounds1 and3 reacts with malononitrile to give β-enaminonitrile6. Phenylhydrazine reacts with3 to give the hydrazone7. Similarly 3-phenyl-5-aminopyrazole reacts with3 to give theSchiff base8.ZusammenfassungDie Reaktion von Ethylcyanacetat mit α-Cyanchalcon1 führt über eineMichael-Addition zum β-Enaminoester3.3 gibt mit Phenylmagnesiumbromid das β-Enaminoketon5. Acetylierung von3 gibt das Acetylderivat4.1 und3 reagieren mit Malodinitril zum β-Enaminonitril6.3 gibt mit Phenylhydrazin das Hydrazon7; 3-Phenyl-5-aminopyrazol reagiert mit3 zurSchiff-Base8.

Computation of Corona Current and its Effect on Travelling Surges Part I-Case of Positive Lightning Surges

A new method for calculating the corona current and its effect on high voltage travelling surges is presented. The corona current is computed using the known theories of corona discharges for different surge voltages and conductor sizes. The calculated corona current wave per meter of the line conductor is used in computing the distortion of the voltage surges as they travel along overhead transmission lines. The calculated current and distortion generally agree with previous experimental findings.

Reactions with the Arylhydrazones of α-Cyanoketones: Utility of Arylhydrazonomesoxalonitriles for the Synthesis of Azoles and Azolines

The arylhydrazonomesoxalonitriles derivatives 1 a - c were utilised for the synthesis of several new pyrimidine, pyridines, triazine and isoxazole derivatives. Compound 1 a reacted with alkyl halides to yield the N-alkyl derivatives 12a, b. The latter reacted with hydrazines to yield the amidrazones 13 a, b.

Retinoic acid improves maturation rate and upregulates the expression of antioxidant-related genes in in vitro matured buffalo (Bubalus bubalis) oocytes

Abstract Retinoic acid, vitamin A metabolite, plays a role in oocyte development and maturation in different ways including gene expression alteration and/or prohibiting oxidative stress. The objective of this study was to examine the effect of 9-cis-retinoic acid (9-cisRA) on the quality and maturation rate of buffalo oocytes. Cumulus-oocyte complexes (COCs, n = 460) were collected from ovaries of slaughtered buffalos. Varying concentrations of 9-cisRA (0, 5, 50, and 200 nM) were added to the maturation medium, and the following parameters were analyzed: (i) maturation and cleavage rates, (ii) mitochondrial activity and reactive oxygen species (ROS) levels, (iii) expression level of antioxidant-related genes (PRDX1, SOD1, CAT, HOMX1, and GPX4) using RT-qPCR. Maturation rate was significantly improved in 5 nM 9-cisRA oocyte group (95.8%, P < .05) compared to control and other treatment groups (86.7% in control group). The same oocyte group exhibited significantly higher mitochondrial membrane potential activity and lower ROS accumulation level compared to other treatment groups. Antioxidant-related genes were up-regulated in oocytes matured with 5 or 50 nM 9-cisRA compared to control and 200 nM 9-cisRA groups. In contrast, 200 nM of 9-cisRA showed a clear down-regulation for antioxidant-related genes except for PRDX1. In conclusion, supplementation of 9-cisRA with a lower concentration (5 nM) to the buffalo oocytes maturation media promotes maturation rate through a protection mechanism that maintains adequate levels of antioxidant-related transcripts and improves mitochondrial activity. However, 9-cisRA has no significant effect on the cleavage rate of the treated oocytes.

187 9-cis RETINOIC ACID IMPROVES MATURATION RATE AND ALTERS GENE EXPRESSION OF IN VITRO-MATURED OOCYTES IN EGYPTIAN BUFFALO.

Retinoic acid, a metabolite of vitamin A, regulates oocyte maturation through multiple mechanisms, including gene expression modulation or preventing oxidative stress. Effects of retinoic acid during oocyte maturation have been reported in several species; however, there have been no studies illustrating these effects in buffalo. Therefore, the objective of this study was to investigate the influence of 9-cis retinoic acid (9-cisRA), an active metabolite of vitamin A, on maturation rate and gene expression during in vitro maturation of buffalo oocytes. Cumulus-oocyte complexes (n=360) were aspirated from surface follicles of Buffalo ovaries collected from local abattoirs and transported to the laboratory in physiological saline (0.9% NaCl) containing antibiotics (100µgmL-1 of streptomycin sulfate and 100IUmL-1 of penicillin) and maintained at 30°C. Grade A cumulus-oocyte complexes (evenly granulated cytoplasm and surrounded by multiple layers of cumulus cells) were randomly divided into 4 groups (90 oocytes/group) and allocated in TCM-199 medium supplemented with 10% fetal bovine serum, 0.2mM sodium pyruvate, 50μgmL-1 of gentamycin, and 10μgmL-1 of FSH and contained 0 (control), 5, 50, or 200 nM of 9-cisRA for maturation. After 24h, maturation rate was calculated as a percentage based on polar body extrusion. In addition, gene expression patterns were analysed for antioxidant related genes (SOD1, CAT, GPX4, HOMX1, and PRDX1) and oocyte quality-related genes (GDF9 and BMP15) using quantitative real-time PCR with GAPDH as a housekeeping gene. Fold changes (FC) were calculated using ΔΔCt method (FC ≥2; P<0.05). The results showed that maturation rate (based on the extrusion of polar body) was significantly higher in 5 nM 9-cisRA oocyte group (49.4±2.1%) compared with the control group (35±1.8%); in contrast, the 200 nM 9-cisRA oocyte group showed the lowest maturation rate (27.2±2.7%). However, the 50 nM 9-cisRA oocyte group showed no significant differences (31.2±3.8%) compared with control group .Oocytes treated with 5 and 50 nM 9-cisRA during in vitro maturation showed significant up-regulation of SOD1 (3.4 and 3.08 FC), CAT (2.7 and 1.8 FC), and HOMX1 (4.5 and 4 FC), and significant down-regulation of BMP15 (-3.7 and -3.6 FC), respectively, compared with the control group. Moreover, GPX4, PRDX1, and GDF9 genes were highly expressed in the 50 nM compared with the control group (13.2, 10.4, and 1.8 FC, respectively). In contrast, the 200 nM 9-cisRA group showed significant down-regulation of CAT (-60.3 FC), GDF9 (-2.5 FC), and BMP15 (-9.7 FC) compared with the control group. In conclusion, these results suggested that a low concentration of 9-cisRA (5 nM) in maturation media can improves maturation rate of buffalo oocytes and up-regulates the expression of oxidative stress response-related genes.