p53 Codon 72 arginine/proline polymorphism and cancer in Sudan

The aim of this report is to determine frequencies and associations of p53 codon 72 arg/pro polymorphism with different types of cancer in Sudan. p53 codon72 arg/pro polymorphism distribution and allele frequencies in 264 samples of different types of cancers were investigated using PCR. The results were compared to 235 normal controls. The results indicated significant differences in frequency and genotype association between different types of cancers. Breast carcinoma patients most prominently showed excess of homozygous arg genotype as compared to controls with an Odd ratio (OR) of 19.44, 95?%CI: 6.6–78.3, P?<?0.0001. Less prominently cervical cancer showed genotype effect of 2.4 OR, 95?%CI: 1.12–5.33, P?=?0.015, while esophageal cancer had an OR of 0.57, 95?%CI: 0.23–1.42, P?=?0.1. In Burkitt’s lymphoma, however, in contrast the homozygous arg accounted for only 6.9?%, (OR 0.18, 95?%CI: 0.02–0.89, P?=?0.018). We concluded that p53 arg/pro polymorphism has different pattern of frequency in different types of cancer among Sudanese patients, indicating perhaps different etiology and biology of these tumours.     

DNA interaction studies of an antiviral drug, ribavirin, using different instrumental methods

Interaction of ribavirin with CT-DNA was investigated by emission, absorption, circular dichroism, and viscosity studies to determine the binding mode and binding constant of this drug with DNA. The calculated binding constant, K(b), obtained from UV-vis absorption studies was 4.6 × 10(3) M(-1). In fluorimetric studies, the enthalpy (ΔH<0) and entropy (ΔS>0) of the reaction between ribavirin and CT-DNA showed a hydrophobic interaction. In addition, in the circular dichroism spectrum, the drug induces a B → A structural transition of CT-DNA. These results demonstrate that ribavirin interacts with CT-DNA via the groove binding mode. It was observed that the drug has ability to cleave supercoiled plasmid DNA.     

Gene cloning,bacterial expression,and purification of calreticulin from Anopheles stephensi (AsCRT)

During the invasion of Plasmodium ookinetes to the mosquito midgut epithelium, several proteins or glycoproteins are involved. Recent study has shown that the calreticulin (CRT) of the midgut from Anopheles albimanus can bind to the protein receptor Pvs25 on surface of Plasmodium vivax ookinetes. Thus, in order to get more insight into the potential roles of Anopheles stephensi calreticulin (AsCRT) in the midgut, we amplified and cloned the full‐length of calreticulin coding sequence from Anopheles stephensi. The AsCRT consists of 1221 bp nucleic acids with one open reading frame (ORF) encoding 406 amino acids and an apparent molecular weight around 46 KDa. Subsequently, the recombinant calreticulin as Glutathione S‐transferase (GST) fusion in pGEX ?6p‐1 expression vector (GST‐AsCRT) was produced in the prokaryotic system under optimum conditions. GST‐AsCRT fusion protein has a molecular weight around 73 KDa. The recombinant protein was detected by Western blotting using a rabbit anti‐GST polyclonal antibody. Here, we report via single protein purification procedure using MagneGST beads, 25 mg of the recombinant protein was obtained per liter of bacterial culture. This is the first report describing the heterologous expression of Anopheles stephensi calreticulin in the prokaryotic system. The production of this recombinant protein will now allow us to further investigate AsCRT molecular protein analyses, characterization of physiochemical properties, as well as interaction between calreticulin and plasmodium protein surface.     

Reactivation of human herpesvirus-6 in natalizumab treated multiple sclerosis patients

The alpha(4) integrin antagonist natalizumab was shown to be effective in patients with immune-mediated disorders but was unexpectedly associated with JC polyomavirus associated progressive multifocal leukoencephalopathy (PML) in two multiple sclerosis (MS) and one Crohn's disease patients. Impaired immune surveillance due to natalizumab treatment may have contributed to the JCV reactivation. As HHV-6 has been suggested to play a role in MS, we asked whether this virus could also have been reactivated during natalizumab therapy. Matched sera and CSF from a limited set of MS patients treated with and without natalizumab were examined for evidence of HHV-6. In addition, we also superinfected a persistent JC virus infected glial cell with HHV-6A to determine if JC virus can be increased. Elevated serum HHV6 IgG and HHV-6A DNA was detected in the CSF of a subset of patients but not controls. We confirmed that superinfection with HHV-6 of a JC virus infected glial cells increased expression of JCV. These results support the hypothesis that treatment with natalizumab may be associated with reduced immune surveillance resulting in reactivation of viruses associated with MS pathogenesis.     

Interaction studies of copper complex containing food additive carmoisine dye with human serum albumin (HSA): Spectroscopic investigations

In this study, the interaction between human serum albumin (HSA) and a copper complex of carmoisine dye; [Cu(carmoisine)₂(H₂O)₂], was studied in vitro using multi‐spectroscopic methods. It was found that the intrinsic fluorescence of HSA was quenched by the addition of the [Cu(carmoisine)₂(H₂O)₂] complex and the quenching mechanism was considered as static quenching by formation of a [Cu(carmoisine)₂(H₂O)₂]–HSA complex. The binding constant was about 10⁴ M^?1 at room temperature. The values of the calculated thermodynamic parameters (ΔH < 0 and ΔS > 0) suggested that both hydrogen bonds and the hydrophobic interactions were involved in the binding process. The site marker competitive experiments revealed that the binding of [Cu(carmoisine)₂(H₂O)₂] to HSA primarily occurred in subdomain IIIA (site II) of HSA. The results of circular dichroism (CD) and UV–vis spectroscopy showed that the micro‐environment of amino acid residues and the conformation of HSA were changed after addition of the [Cu(carmoisine)₂(H₂O)₂] complex. Finally, the binding of the [Cu(carmoisine)₂(H₂O)₂] complex to HSA was modelled by a molecular docking method. Excellent agreement was obtained between the experimental and theoretical results with respect to the binding forces and binding constant.     

The prevalence and associated risk factors of restless legs syndrome among Saudi adults

Sleep and Biological Rhythms - The aim of this cross-sectional study was to determine the prevalence, risk factors, other associated sleep disorders and commodities of Restless Legs Syndrome (RLS)...     

Intercalation of a Zn(II) complex containing ciprofloxacin drug between DNA base pairs

In this study, an attempt has been made to study the interaction of a Zn(II) complex containing an antibiotic drug, ciprofloxacin, with calf thymus DNA using spectroscopic methods. It was found that Zn(II) complex could bind with DNA via intercalation mode as evidenced by: hyperchromism in UV–Vis spectrum; these spectral characteristics suggest that the Zn(II) complex interacts with DNA most likely through a mode that involves a stacking interaction between the aromatic chromophore and the base pairs of DNA. DNA binding constant (K_b = 1.4 × 10⁴ M^?1) from spectrophotometric studies of the interaction of Zn(II) complex with DNA is comparable to those of some DNA intercalative polypyridyl Ru(II) complexes 1.0 ?4.8 × 10⁴ M^?1. CD study showed stabilization of the right-handed B form of DNA in the presence of Zn(II) complex as observed for the classical intercalator methylene blue. Thermodynamic parameters (ΔH < 0 and ΔS < 0) indicated that hydrogen bond and Van der Waals play main roles in this binding prose. Competitive fluorimetric studies with methylene blue (MB) dye have shown that Zn(II) complex exhibits the ability of this complex to displace with DNA-MB, indicating that it binds to DNA in strong competition with MB for the intercalation.     

A multi-spectroscopic and molecular docking approach to investigate the interaction of antiviral drug oseltamivir with ct-DNA

The possible interaction between the antiviral drug oseltamivir and calf thymus DNA at physiological pH was studied by spectrophotometry, competitive spectrofluorimetry, differential pulse voltammogram (DPV), circular dichroism spectroscopy (CD), viscosity measurements, salt effect, and computational studies. Intercalation of oseltamivir between the base pairs of DNA was shown by a sharp increase in specific viscosity of DNA and a decrease of the peak current and a positive shift in differential pulse voltammogram. Competitive fluorescence experiments were performed using neutral red (NR) as a probe for the intercalation binding mode. The studies showed that oseltamivir is able to release the NR.     

DNA binding affinity of a macrocyclic copper(II) complex: Spectroscopic and molecular docking studies

The interaction of a novel macrocyclic copper(II) complex, ([CuL(ClO₄)₂] that L is 1,3,6,10,12,15-hexaazatricyclo[13.3.1.1^6,10]eicosane) with calf thymus DNA (ct-DNA) was investigated by various physicochemical techniques and molecular docking at simulated physiological conditions (pH = 7.4). The absorption spectra of the Cu(II) complex with ct-DNA showed a marked hyperchroism with 10 nm blue shift. The intrinsic binding constant (K_b) was determined as 1.25 × 10⁴ M^?1, which is more in keeping with the groove binding with DNA. Furthermore, competitive fluorimetric studies with Hoechst33258 have shown that Cu(II) complex exhibits the ability to displace the ct-DNA-bound Hoechst33258 indicating that it binds to ct-DNA in strong competition with Hoechst33258 for the groove binding. Also, no change in the relative viscosity of ct-DNA and fluorescence intensity of ct-DNA-MB complex in the present of Cu(II) complex is another evidence to groove binding. The thermodynamic parameters are calculated by van't Hoff equation, which demonstrated that hydrogen bonds and van der Waals interactions played major roles in the binding reaction. The experimental results were in agreement with the results obtained via molecular docking study.