Prognostic value of exercise longitudinal right ventricular free wall strain in patients with sickle cell disease

Longitudinal right ventricular free wall strain (RVFWS) has been identified as an independent prognostic marker in patients with pulmonary hypertension. Little is known however about the prognostic value of RVFWS in patients with sickle cell (SC) disease, particularly during exercise. We therefore examined the prognostic significance of RVFWS both at rest and with exercise in patients with SC disease and normal resting systolic pulmonary artery pressure (SPAP). Consecutive patients with SC disease referred for bicycle ergometer stress echocardiography (SE) were enrolled ftom July 2019 to January 2021. All patients had measurable tricuspid regurgitation velocity (TRV). Conventional echocardiography parameters, left ventricular global longitudinal strain (LVGLS), RVFWS, and ventriculoarterial coupling indices (TAPSE/SPAP and RVFWS/SPAP) were assessed at rest and peak exercise. Repeat SE was performed at a median follow-up of 2 years. The cohort consisted of 87 patients (mean age was 31 ± 11 years, 66% females). All patients had normal resting TRV < 2.8 m/s, RVFWS and LVGLS at baseline. There were 23 (26%) patients who had peak stress RVFWS < 20%. They had higher resting and peak stress TRV and SPAP, but lower resting and peak stress TAPSE/SPAP, RVFWS/SPAP, and LVGLS as well as lower peak stress cardiac output when compared to patients with peak stress RVFWS ≥ 20% (p < 0.05). Patients with baseline peak stress RVFWS < 20% had a significant decrease in exercise performance at follow-up (7.5 ± 2.7 min at baseline vs. 5.5 ± 2.8 min at follow-up, p < 0.001). In the multivariate analysis, baseline peak stress RVFWS was the only independent predictor of poorer exercise performance at follow-up [odds ratio 8.2 (1.2, 56.0), p = 0.033]. Among patients with SC disease who underwent bicycle ergometer SE, a decreased baseline value of RVFWS at peak stress predicted poorer exercise time at follow-up.

Primary retrograde urinary drainage using image and endoscopy guidance via urostomies

AIM

To report the technical success of image and endoscopy-guided retrograde trans-urostomy urinary drainage as a primary catheter placement method performed by interventional radiology (IR).

MATERIALS AND METHODS

Nine patients (15 attempted drain placements) with ureteric obstruction following radical cystectomy and urostomy creation were included. The patients were referred to IR for urinary drainage. All patients underwent primary image and endoscopy-guided retrograde trans-urostomy urinary drainage.

RESULTS

Primary image and endoscopy-guided retrograde trans-urostomy urinary drainage was successful in 13/15 (86.6%) attempts. The proposed technique had a limited complication rate omitting the percutaneous nephrostomy access step.

CONCLUSION

Primary image and endoscopy guided retrograde trans-urostomy urinary drainage should be considered before percutaneous nephrostomy in all patients with a urostomy.

Generation and utility of a single-chain fragment variable monoclonal antibody platform against a baculovirus expressed recombinant receptor binding domain of SARS-CoV-2 spike protein

As the second wave of COVID-19 launched, various variants of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) have emerged with a dramatic global spread amongst millions of people causing unprecedented case fatalities and economic shut-downs. That initiated a necessity for developing specific diagnostics and therapeutics along with vaccines to control such a pandemic. This endeavor describes generation of murine derived recombinant single-chain fragment variable (scFv) as a monoclonal antibody (MAb) platform targeting the receptor binding domain (RBD) of Spike protein of SARS-CoV-2. A specific synthesized RBD coding sequence was cloned and expressed in Baculovirus expression system. The recombinant RBD (rRBD) was ascertained to be at the proper encoding size of ∼ 600bp and expressed protein of the molecular weight of ∼ 21KDa. Purified rRBD was proved genuinely antigenic and immunogenic, exhibiting specific reactivity to anti-SARS-CoV-2 antibody in an indirect enzyme-linked immunosorbent assay (ELISA), and inducing strong seroconversion in immunized mice. The scFv phage display library against rRBD was successfully constructed, revealing ∼ 90 % recombination frequency, and great enriching factor reaching 88 % and 25 % in polyclonal Ab-based and MAb-based ELISAs, respectively. Typically, three unique scFvs were generated, selected, purified and molecularly identified. That was manifested by their: accurate structure, close relation to the mouse immunoglobulin (Ig) superfamily, right anchored six complementarily-determining regions (CDRs) as three within variable heavy (vH) and variable light (vL) regions each, and proper configuration of the three-dimensional (3D) structure. Besides, their expression downstream in a non-suppressive amber codon of E. coli strain SS32 created a distinct protein band at an apparent molecular weight of ∼ 27KDa. Moreover, the purified scFvs showed authentic immunoreactivity and specificity to both rRBD and SARS-CoV-2 in western blot and ELISA. Accordingly, these developed scFvs platform might be a functional candidate for research, inexpensive diagnostics and therapeutics, mitigating spread of COVID-19.

Setup for pressurizing thin films through the superconductor-insulator transition

We describe an experimental setup designed for transport measurement of thin disordered superconducting films as a function of pressure up to several GPa. We use a specially designed single screw diamond anvil cell that allows the gradual increase of high pressure at cryogenic temperatures. By depositing amorphous films of disordered superconducting indium oxide directly on the diamond, we avoid the effect of pressure-induced structural changes in the substrate. Using this technique, we are able to drive thin films through a pressure tuned superconductor-insulator transition.

Removal of 3C protease from the 3ABC improves expression, solubility, and purification of the recombinant 3AB of foot-and-mouth disease virus

During an ongoing outbreak of Foot-and-Mouth Disease Virus (FMDV), it is crucial to distinguish naturally infected from vaccinated seropositive animals. This would support clinical assessment and punctual vigilance. Assays based on 3ABC non-structural protein as an antigen are reliable for this intention. However, the insolubility and degradation of recombinant 3ABC during expression and purification are serious challenges. In this study, alternatively to expressing the recombinant 3ABC (r3ABC), we expressed the 3AB coding sequence (~672 bp) as a recombinant protein (r3AB) with a molecular mass of ~26 KDa. Analytical data from three-dimensional structure, hydrophilicity, and antigenic properties for 3ABC and 3AB exhibited the 3C protein as a hydrophobic, while 3AB as a hydrophilic and highly antigenic protein. The expressed r3AB was recovered as a completely soluble matter after merely native purification, unlike the full expressed r3ABC. Immunoreactivity of r3AB to anti-FMDV antibody in infected sera with different FMDV serotypes was confirmed by the western blot and indirect ELISA. Besides, the authentic antigenicity of purified r3AB was demonstrated through its ability to induce specific seroconversion in mice. Summarily, the removal of 3C: has influenced neither 3D structure nor antigenic properties of the purified r3AB, overcame insolubility and degradation of the r3ABC, and generated a potential superior antigen (r3AB) for herd screening of animals to any FMDV serotype.

Utilization of a recombinant defensin from Maize (Zea mays L.) as a potential antimicrobial peptide

The search for effective and bioactive antimicrobial molecules to  encounter the medical need for new antibiotics is an encouraging area of research. Plant defensins are small cationic, cysteine-rich peptides with a stabilized tertiary structure by disulfide-bridges and characterized by a wide range of biological functions. The heterologous expression of Egyptian maize defensin (MzDef) in Escherichia coli and subsequent purification by glutathione affinity chromatography yielded 2 mg/L of recombinant defensin peptide. The glutathione-S-transferase (GST)-tagged MzDef of approximately 30 kDa in size (26 KDa GST +  ~ 4 KDa MzDef peptide) was immunodetected with anti-GST antibodies. The GST-tag was successfully cleaved from the MzDef peptide by thrombin, and the removal was validated by the Tris-Tricine gel electrophoresis. The MzDef induced strong growth inhibition of Rhizoctonia solani, Fusarium verticillioides, and Aspergillus niger by 94.23%, 93.34%, and 86.25%, respectively, whereas relatively weak growth inhibitory activity of 35.42% against Fusarium solani was recorded. Moreover, strong antibacterial activities were demonstrated against E. coli and Bacillus cereus and the moderate activities against Salmonella enterica and Staphylococcus aureus at all tested concentrations (0.1, 0.2, 0.4, 0.8, 1.6, and 3.2 µM). Furthermore, the in vitro MTT assay exhibited promising anticancer activity against all tested cell lines (hepatocellular carcinoma, mammary gland breast cancer, and colorectal carcinoma colon cancer) with IC50 values ranging from 14.85 to 29.85 µg/mL. These results suggest that the recombinant peptide MzDef may serve as a potential alternative antimicrobial and anticancer agent to be used in medicinal application.

Characterization, cloning, expression and bioassay of vip3 gene isolated from an Egyptian Bacillus thuringiensis against whiteflies

Throughout the vegetative life of Bacillus thuringiensis, vegetative insecticidal proteins (Vip) are produced and secreted. In the present study, the vip3 gene isolated from Bacillus thuringiensis, an Egyptian isolate, was successfully amplified (2.4 kbp) and expressed using bacterial expression system. The molecular mass of the expressed protein was verified using SDS-PAGE and western blot analysis. Whiteflies were also screened for susceptibility to the expressed Vip3 protein (LC50). In addition, ST50 was determined to assess the kill speed of the expressed Vip3 protein against whiteflies compared to the whole vegetative proteins. The results showed that the potency of whole B. thuringiensis vegetative proteins against whiteflies was slightly higher than the expressed Vip3 protein with 4.7-fold based on LC50 value. However, the ST50 parameter showed no significant difference between both the B. thuringiensis vegetative proteins and the expressed Vip3 alone. The results showed that the vip3 gene was successfully expressed in an active form which showed high susceptibility to whiteflies based on the virulence parameters LC50 and ST50. To our knowledge, this study showed for the first time the high toxicity of the expressed Vip3 proteins of B. thuringiensis toward whiteflies as a hopeful and promising bio-control agent.

Expression of 1B capsid protein of Foot-and-mouth disease virus (FMDV) using baculovirus expression system and its validation in detecting SAT 2- specific antisera

Foot-and-mouth disease virus (FMDV) is one of the most devastating animal viruses that affect livestock worldwide. The 1B capsid of FMDV has been widely used to detect and confirm the infection. In the present study, the sequence coding for 1B subunit of FMDV capsid was expressed in insect cells using the baculovirus expression system under the polyhedrin (polh) promoter. The expression of 1B capsid protein was validated in the culture filtrate of insect cells using SDS-PAGE and western blotting. The culture filtrate containing recombinant 1B capsid (r1B) was used as a coated antigen in an indirect enzyme-linked immunosorbent assay (ELISA). The antigenicity and specificity of r1B against SAT 2 serotype-specific antibodies were assessed. Our results revealed that a protein concentration as low as 25 ng could detect SAT 2-specific antibodies in ELISA. The results highlight the application of insect cells developed r1B protein in the detection of FMDV. Further studies are required to determine the ability of r1B to detect other FMDV serotypes.

Expressing the immunodominant projection domain of infectious bursal disease virus fused to the fragment crystallizable of chicken IgY in yellow maize for a prospective edible vaccine

Control of Infectious bursal disease virus (IBDV) in endemic countries has been based on early immunization of chicks using conventional live or inactivated vaccines that became not fully effectual and have biosafety concerns. This endeavor seeks generating a recombinant chimeric protein merging the projection domain (PD) of IBDV VP2 capsid with the fragment crystallizable (Fc) of avian IgY (FcIgY), in maize as a prospective poultry edible vaccine. The PD sequence was built on the basis of very virulent IBDV isolates circulating in Egypt. After optimization of codon-usage in maize, sequences of PD and FcIgY were effectively expressed in two elites of yellow maize via bombardment transformation in immature embryos. Chimeric protein amount in stable transgenic samples ranged from1.36% to 3.03% of the total soluble protein based on tissue age and maize cultivar. IBDV VP2 coding sequence was amplified from viral RNA, cloned, and expressed in E. coli. A group of Balb/C mice were hyper-immunized with purified recombinant VP2 protein for raising anti- recombinant VP2 antibodies (anti-rVP2 Ab). Proper expression in maize and immunoreactivity of the chimeric protein (PD-FcIgY) to chicken anti- IBDV and anti-rVP2 Ab were confirmed by both direct and indirect double antibody sandwich (DAS)-ELISAs as well as western blotting. Seeds of regenerated transgenic maize will be validated for chickens as edible vaccination in further studies.

Construction, Expression and Evaluation of Recombinant VP2 Protein for serotype-independent Detection of FMDV Seropositive Animals in Egypt

Foot-and-mouth disease virus (FMDV) is one of the most devastating viral pathogens of cloven-hoofed animals. The detection of antibodies (Ab) against FMDV structural proteins (SP) using virus neutralization test (VNT) and liquid-phase blocking ELISA (LPBE) is the standard procedure in use for monitoring seroconversion in animals post vaccination, the prevalence of infection-surveillance, proving clinical cases and seronegative status of FMDV-free/naïve-animals prior transportation. However, due to variations within SP of FMDV serotypes, each serotype-specific Ab should be detected separately which is laborious and time-consuming. Accordingly, it is crucial to develop a sensitive, rapid, and accurate test capable of detecting FMDV-specific Ab, regardless its serotype. This study describes the heterologous expression of VP2 protein in E. coli, and its evaluation as a capture antigen in a simple indirect ELISA for serotype-independent detection of anti-FMDV Ab. Sequence analysis revealed that the VP2-coding sequence is considerably conserved among FMDV serotypes. The recombinant VP2 (rVP2), a 22 kDa polypeptide, was purified to near homogeneity by affinity chromatography under native conditions. Immunoreactivity of the rVP2 was confirmed by using a panel of positive sera including sera from animals vaccinated with the local trivalent vaccine and guinea pig FMDV antiserum, which is routinely used as tracing/detecting Ab in LPBE testing. The results obtained from the VP2-based ELISA were comparable to those determined by VNT and LPBE standard diagnostic assays. Specificity and sensitivity of rVP2 in capturing anti-FMDV Ab were 98.3% and 100%, respectively. The developed VP2-ELISA is proved reliable and time-efficient assay for detection of FMDV seropositive animals, regardless the FMDV serotype that can be implemented in a combination with VNT and/or LPBE for rapid diagnosis of an ongoing FMDV infection.