55 research outputs found
Chaperone-Assisted Soluble Expression of a Humanized Anti-EGFR ScFv Antibody in E. Coli
Purpose: Formation of inclusion bodies is a
considerable obstacle threatening the advantages of E. coli expression
system to serve as the most common and easiest system in recombinant protein
production. To solve this problem, several strategies have been proposed among
which application of molecular chaperones is of remarkable consideration. The
aim of this study was to evaluate the effects of molecular chaperones on
soluble expression of aggregation-prone humanized single chain antibody.
Methods: To increase the solubility of a humanized
single chain antibody (hscFv), different chaperone plasmids including PG-tf2
(GroES- GroEL- tig), ptf16 (tig) and pGro7 (GroES- GroEL) were co-expressed in
BL21 cells containing pET-22b- hscFv construct. The solubility of recombinant
hscFv was analyzed by SDS-PAGE. After purification of soluble hscFv by Ni-NTA
column, the biological activity and cytotoxicity of the recombinant protein
were tested by ELISA and MTT assay, respectively.
Results: SDS-PAGE analysis of the hscFv revealed that
chaperone utility remarkably increased (up to 50%) the solubility of the
protein. ELISA test and MTT assay analyses also confirmed the biological
activity of the gained hscFv in reaction with A431 cells (OD value: 2.6) and
inhibition of their proliferation, respectively.
Conclusion: The
results of this study revealed that co-expression of chaperones with hscFv
leads to remarkable increase in the solubility of the recombinant hscFv, which
could be of great consideration for large scale production of recombinant
single chain antibodies
Analysis of Methylation and Expression Profile of Foxp3 Gene in Patients with Behçet’s Syndrome
Forkhead box P3 (Foxp3) gene is an important means in the Treg cells function, in both
maintenances of immune tolerance and regulation of response. Epigenetic modifications of the
foxp3 gene at its regulatory regions control the chromatin accessibility for the transcription factors
and other transcriptional regulators in order to control Foxp3 expression. In addition, the
methylation status of CpG islands within the Foxp3 promoter and regulatory elements regulate the
expression of Foxp3. This study was performed to assess the role of the foxp3 gene in patients
with Behçet’s syndrome (BS).
Venous blood samples were collected from all participants and peripheral blood mononuclear
cells (PBMC) were extracted through Ficoll-Hypaque method. Genomic DNA was randomly
sheared by sonication and immunoprecipitated with a monoclonal antibody. The status
methylation of the foxp3 gene was estimated in 108 blood samples of active BS patients and
healthy individuals (controls); using methylation DNA immunoprecipitation (MeDIP) technique.
Expression analysis was carried out; using Real-time PCR.
The expression of foxp3 gene in the patients' group (mean±SD: 1.79±1.12) was significantly
lower than the healthy group (mean±SD: 2.73±1.33) (p<001). Also, the methylation levels of
Foxp3 promoter showed that its level in patients (mean±SD: 2.3±1.16) was higher than the
healthy group (mean±SD: 1.85±0.59). However, this increase was not statistically significant
(p>0.05). Also, these results indicated that increasing the amount of methylation of the foxp3 gene
by reducing its expression leads to an increase and intensifying of the disease.
The decrease in Foxp3 expression is possibly associated with hypermethylation of the gene,
and it can be considered as a risk factor for BS. Future studies may be needed to identify the
capability of specific DNA methylation alterations in this syndrome
Lysophosphatidate Induces Chemo-Resistance by Releasing Breast Cancer Cells from Taxol-Induced Mitotic Arrest
Taxol is a microtubule stabilizing agent that arrests cells in mitosis leading to cell death. Taxol is widely used to treat breast cancer, but resistance occurs in 25-69% of patients and it is vital to understand how Taxol resistance develops to improve chemotherapy. The effects of chemotherapeutic agents are overcome by survival signals that cancer cells receive. We focused our studies on autotaxin, which is a secreted protein that increases tumor growth, aggressiveness, angiogenesis and metastasis. We discovered that autotaxin strongly antagonizes the Taxol-induced killing of breast cancer and melanoma cells by converting the abundant extra-cellular lipid, lysophosphatidylcholine, into lysophosphatidate. This lipid stimulates specific G-protein coupled receptors that activate survival signals.In this study we determined the basis of these antagonistic actions of lysophosphatidate towards Taxol-induced G2/M arrest and cell death using cultured breast cancer cells. Lysophosphatidate does not antagonize Taxol action in MCF-7 cells by increasing Taxol metabolism or its expulsion through multi-drug resistance transporters. Lysophosphatidate does not lower the percentage of cells accumulating in G2/M by decreasing exit from S-phase or selective stimulation of cell death in G2/M. Instead, LPA had an unexpected and remarkable action in enabling MCF-7 and MDA-MB-468 cells, which had been arrested in G2/M by Taxol, to normalize spindle structure and divide, thus avoiding cell death. This action involves displacement of Taxol from the tubulin polymer fraction, which based on inhibitor studies, depends on activation of LPA receptors and phosphatidylinositol 3-kinase.This work demonstrates a previously unknown consequence of lysophosphatidate action that explains why autotaxin and lysophosphatidate protect against Taxol-induced cell death and promote resistance to the action of this important therapeutic agent
Peoples’ attitude toward COVID-19 vaccine, acceptance, and social trust among African and Middle East countries
Background: To end the COVID-19 pandemic, a large part of the world must be immune to the virus by vaccination. Therefore, this study aimed to gauge intent to be vaccinated against COVID-19 among ordinary people and to identify attitudes towards vaccines and barriers for vaccine acceptance. Methods: The study population comprises 1880 people residing in different countries that answer a prepared questionnaire. The questionnaire topics are demographics, historical issues, participants’ attitudes and beliefs regarding vaccines, concerns, and vaccine hesitancy. Results: Attitudes and beliefs relating to vaccines in general, and the COVID-19 vaccine, were ascertained. Overall, 66.81% of the contributors would like to be vaccinated against COVID-19, while %33.19 did not intend to be vaccinated. Reasons for COVID-19 vaccine hesitancy included concern regarding vaccine side effects, fear of getting sick from the uptake of the vaccine, and the absence of accurate vaccine promotion news. Individuals with higher education believe that India (68.6%) produces the best vaccine (P<0.001), while healthcare workers think the Chinese vaccine (44.2%) is the best (P=0.020). Individuals with higher education have not been vaccinated, not be healthcare workers, and females were the most contributors to effective of the vaccine in reducing mortality from COVID-19 disease. Conclusion: Given the degree of hesitancy against COVID-19 vaccination, a multifaceted approach to facilitate vaccine uptake that includes vaccine education, behavioral change strategies, and health promotion, is paramount
Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study
Summary
Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally.
Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies
have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of
the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income
countries globally, and identified factors associated with mortality.
Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to
hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis,
exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a
minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical
status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary
intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause,
in-hospital mortality for all conditions combined and each condition individually, stratified by country income status.
We did a complete case analysis.
Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital
diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal
malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome
countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male.
Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3).
Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income
countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups).
Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome
countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries;
p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients
combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11],
p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20
[1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention
(ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety
checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed
(ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of
parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65
[0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality.
Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome,
middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will
be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger
than 5 years by 2030
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Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation
Pharmacogenetics and drug-induced nephrotoxicity in renal transplant recipients
Introduction:
The advent of calcineurin inhibitors (CNIs), as the leading
immunosuppressive agents, not only has revolutionized the transplant
medicine but also made it a better therapeutic intervention that
guarantees the graft outcome and improves the survival rate of patients.
However, genetic polymorphism(s) in the CNIs metabolic substrates genes
(CYP3A4, CYP3A5) and their transporter such as P-glycoprotein (P-gp)
can influence the CNIs metabolism and elicit some possible systemic and
intra-renal exposures to drugs and/or metabolites with differential
risk of nephrotoxicity, jeopardizing the transplantation.
Methods:
In the current study, we review the recent literatures to evaluate the
effects of genetic polymorphisms of the genes involved in development of
chronic calcineurin nephrotoxicity and progression of chronic allograft
dysfunction (CAD) providing an extensive overview on their clinical
impacts.
Results:
Identifying the inherited genetic basis for the inter-individual
differences in terms of drug responses and determining the risk of
calcineurin-mediated nephrotoxicity and CAD allow optimized personalized
administration of these agents whith minimal adverse effects.
Conclusion:
Pharmacogenetics characteristics of CYP isoforms (CYP3A) and efflux
transporters (P-gp and MRP), involved in metabolism and extracellular
transportation of the immunosuppressive CNIs, can be of pivotal
information in the pharmacotherapy of the renal-transplant recipient
patients. Such information can be used for the successes clinical
interventions to attain an improved drug administration strategy with
reduced rates of rejection and toxicity
Doxorubicin Changes Bax /Bcl-xL Ratio, Caspase-8 and 9 in Breast Cancer Cells
Purpose: Doxorubicin is administrated as a single agent in first-line
therapy of breast cancer to induce apoptosis in tumor cells. Bax,
Bcl-xL, Caspase-8 and 9 proteins are involved in induction of apoptosis. The
present study describes Bax, Bcl-xL gene expression
and Caspase-8 and 9 protein levels in MCF-7 cells incubated with doxorubicin at
different doses an incubation times.
Methods: The cytotoxic
effects of doxorubicin were studied using MTT assay. MCF-7
cells were treated with three concentrations of doxorubicin (0.1, 0.5, 1 μM)
and incubated for 24, 48 and 72 hours then expression levels of Bax and Bcl-xL
genes were elucidated by Real-time RT-PCR technique and protein levels of
caspase-8 and caspase-9 proteins were measured using ELISA method.
Morphological modifications of the cells were also monitored via light
microscopic images.
Results:
Doxorubicin decreased the anti-apoptotic Bcl-xL and increased
pro-apoptotic Bax mRNA levels. Doxorubicin induced a significant
increase in Bax /Bcl-xL ratio in all doses and incubation
times (p<0.05). Highest (more than 10 fold) increase in Bax /Bcl-xL
ratio was revealed after 48 h incubation of the cells with in all
doses of doxorubicin. Doxorubicin also increased caspase-9 level in a time and
dose-dependent manner, while
caspase-8 level didn't follow time and dose dependency pattern.
Conclusion: Our results confirm that
doxorubicin induces mitochondrial-dependent apoptosis by down-regulation of
Bcl-xL and up- regulation of Bax and caspase-9 expressions
Sphingosine 1-phosphate interacts with Survivin pathway to enhance tumorigenesis in cancer cells
Objective(s):Degradation of sphingosine 1-phosphate (S1P), as a bioactive lipid, or deregulation of its production involves in tumor progression, metastasis and chemoresistance. Since the tumor progression effects of S1P and its mechanism in chronic lymphoblastic leukemia and non-small cell lung cancer is not fully understood, we investigated the role and one of the mechanisms of S1P in tumor progression of SKW3 and H1299 cells.
Materials and Methods: The effects of S1P on proliferation, invasion and migration was studied using MTT assay, soft-agar colony forming assay and trans-well migration assay, respectively. In order to find out the mechanisms of S1P action, the role of S1P on expression of Survivin gene was assessed by real-time RT-PCR.
Results:Our results demonstrated that although invasion was shown only in H1299 cells, low concentration of S1P, especially at 1 μM, mediated proliferation and migration in both cell lines. In addition, these effects of S1P in tumor progression are S1P receptor-dependent, and Survivin plays a key role in S1P tumorigenesis.
Conclusion:Our results confirmed the involvement of S1P and its receptors in tumor progression of SKW3 and H1299. We also investigated another mechanism of S1P involved in cell survival, tumor progression, and Survivin signaling. In conclusion, data demonstrated the importance of this molecule as a target for designing new anticancer drugs such as anti-S1P monoclonal antibody for inhibiting major downstream signaling, which plays significant role in tumorigenesis
A microRNA isolation method from clinical samples
Introduction: microRNAs (miRNAs) are considered to be novel molecular biomakers that could be exploited in the diagnosis and treatment of different diseases. The present study aimed to develop an efficient miRNA isolation method from different clinical specimens.
Methods: Total RNAs were isolated by Trizol reagent followed by precipitation of the large RNAs with potassium acetate (KCH3COOH), polyethylene glycol (PEG) 4000 and 6000, and lithium chloride (LiCl). Then, small RNAs were enriched and recovered from the supernatants by applying a combination of LiCl and ethanol. The efficiency of the method was evaluated through the quality, quantity, and integrity of the recovered RNAs using the A260/280 absorbance ratio, reverse transcription PCR (RT-PCR), and quantitative real-time PCR (q-PCR).
Results: Comparison of different RNA isolation methods based on the precipitation of DNA and large RNAs, high miRNA recovery and PCR efficiency revealed that applying potassium acetate with final precipitation of small RNAs using 2.5 M LiCl plus ethanol can provide high yield and quality small RNAs that can be exploited for clinical purposes.
Conclusion: The current isolation method can be applied for most clinical samples including cells, formalin-fixed and paraffin-embedded (FFPE) tissues and even body fluids with a wide applicability in molecular biology investigations
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