Ahmed Zaid

• MSc PhD
• Professor (Full) at University of Tripoli

Unlabelled: The gene encoding the proprotein convertase subtilisin/kexin type 9 (PCSK9) is linked to familial hypercholesterolemia, as are those of the low-density lipoprotein receptor (LDLR) and apolipoprotein B. PCSK9 enhances LDLR degradation, resulting in low-density lipoprotein accumulation in plasma. To analyze the role of hepatic PCSK9, tot...

The proprotein convertase subtilisin/kexin type 9 (PCSK9) promotes independently of its enzymatic activity the degradation of the low-density lipoprotein (LDL) receptor. PCSK9 gain of function in humans leads to autosomal dominant hypercholesterolemia, whereas the absence of functional PCSK9 results in ≈7-fold lower levels of LDL cholesterol. This...

Familial hypercholesterolemia (FH) is a well-understood Mendelian disorder that increases the risk of cardiovascular disease (CVD), a leading cause of mortality in Middle Eastern and North African (MENA) countries. Review the reporting status of FH mutations across MENA and propose a systemic and strategic method for building a MENA FH registry. Sy...

Factor V Leiden G1691A (FVL) and Factor II prothrombin G20210A (PGM) mutations are the leading causes of thrombophilia. In this study, we have investigated the prevalence of the FVL G1691A and PGM G20210A single nucleotide polymorphisms (SNPs) among Libyan deep vein thrombosis (DVT) and myocardial infarction (MI) patients. SNP genotyping was perfor...

The prevalence of vitamin D deficiency has recently been recognized in different parts of the world, even affecting healthy populations. The deficiency of vitamin D can lead to rickets in children and osteomalacia in adults. Few studies have been done to evaluate the status of vitamin D in the medical community around the world. No studies have bee...

Background: The recent COVID-19 epidemic outbreak is an ongoing crisis that is causing

Background The coronavirus disease 2019 (COVID-19) pandemic may have a potentially serious effect on mental health and increase the risk of anxiety, depression, and post-traumatic stress disorders in people. In this study, we aimed to determine the prevalence of psychological illness and the impact of the COVID-19 pandemic on the Libyan population’...

Petroleum refineries are largest chemical industries that are responsible for emission of several pollutants into the atmosphere. Benzene and its metabolites are regarded as the most hazardous compounds that are emitted by petroleum refineries. These contribute to toxic oxidants, which cause many serious health risks to petroleum refineries workers...

Background The first case of the novel coronavirus disease 2019 (COVID-19) in Libya was diagnosed in March 2020. We aimed to determine the epidemiological, clinical, and laboratory characteristics of COVID-19 in Libya. Method In this retrospective descriptive study, we analyzed the demographics, initial clinical presentation, history, comorbiditie...

Background This study determined the knowledge, attitudes, and practice regarding COVID-19 and assessed the acceptance of the COVID-19 vaccine among healthcare workers and the general population. Methods A web-based, cross-sectional study was conducted using convenience sampling in Libya from December 1 to 18, 2020 among the general population and...

Background The coronavirus disease (COVID-19) pandemic has severely affected African countries, specifically the countries, such as Libya, that are in constant conflict. Clinical and laboratory information, including mortality and associated risk factors in relation to hospital settings and available resources, about critically ill patients with CO...

Background: The COVID-19 pandemic has led to an increase in the risk of suicide, uncertainty, mental stress, terror, annoyance, weariness, financial issues, and frustration. We aim to determine the prevalence of insomnia, depressive and anxiety symptoms, and their associated factors among Libyan populations during the COVID-19 pandemic and the civi...

Objective: We aimed to determine the prevalence of burnout among hospital healthcare workers in Libya during the coronavirus disease (COVID-19) pandemic and civil war. Methods: A cross-sectional study was conducted from April 18 to May 2, 2020 among Libyan healthcare workers. Data on participant characteristics were collected with a specifically de...

The Coronavirus Disease 2019 (COVID-19) pandemic has caused an unprecedented disruption in medical education and healthcare systems worldwide. The disease can cause life-threatening conditions and it presents challenges for medical education, as instructors must deliver lectures safely, while ensuring the integrity and continuity of the medical edu...

Objective Healthcare workers, particularly those working in departments that provide care for patients with coronavirus disease 2019 (COVID-19), are at a higher risk of this contagious disease than those who work in other departments. The aim of this study was to assess the psychological status of healthcare workers during the COVID-19 outbreak, wh...

Objectives We aimed to identify the prevalence of depression and anxiety among physicians working in the emergency departments of nine tertiary care centres in Libya. Design This was a cross-sectional study. Setting Nine main tertiary centres in Libya Participants Emergency department doctors were surveyed between December 2018 and February 2019...

COVID-19, caused by the SARS-CoV-2 virus, is spreading rapidly worldwide, with devastating consequences for patients, healthcare workers, health systems, and economies. As it reaches low- and middle-income countries, the pandemic puts healthcare workers at high risk and challenges the abilities of healthcare systems to respond to the crisis. This s...

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common genetic kidney disorders with the incidence of 1 in 1,000 births. ADPKD is genetically heterogeneous with two genes identified: PKD1 (16p13.3, 46 exons) and PKD2 (4q21, 15 exons). Eighty five percent of the patients with ADPKD have at least one mutation in the PKD1 gene...

Familial hypercholesterolemia (FH) is an autosomal dominant genetic disorder of lipid metabolism, associated with elevated levels of low-density lipoprotein-cholesterol (LDLC), which can lead to premature cardiovascular disease and early death. Early diagnosis and initiation of treatment is important to prevent morbidity and mortality. Autosomal do...

The GC-box is an important transcriptional regulatory element present in the promoters of many mammalian genes, and is found in most, if not all, oxidative phosphorylation (OXPHOS) promoters. In the present study we examine the effects of three Sp1 family members (Sp2, Sp3, and Sp4) on the adenine nucleotide translocase 2, cytochrome c1, F1-ATPase...

Copper and zinc are essential trace elements; they are cofactors for activation of many enzymes, their deficiency increases susceptibility to pathogens and causes impairment of growth and development during childhood. Diarrhoea is a very frequent illness in young children especially in developing countries, it has been reported that during acute an...

The proprotein convertase PC5/6 cleaves protein precursors after basic amino acids and is essential for implantation in CD1/129/Sv/C57BL/6 mixed-background mice. Conditional inactivation of Pcsk5 in the epiblast but not in the extraembryonic tissue bypassed early embryonic lethality but resulted in death at birth. PC5/6-deficient embryos exhibited...

The mammalian secretory proprotein convertases are part of a family of nine serine proteinases of the subtilisin-type. Seven of them cleave after basic amino acids and are called PC1/3, PC2, furin, PC4, PC5/6, PACE4 and PC7. The two other convertases SKI-1/S1P and PCSK9 are implicated in cholesterol and/or fatty acid metabolism. The convertases PC5...

Background: PCSK9 is primarily expressed in liver and intestine and was recently identified as the third locus implicated in autosomal dominant hypercholesterolemia, after LDLR and APOB. PCSK9 transits through the secretory pathway, associates with LDLR and triggers its degradation in endodomal/lysosomal compartments. Hypothesis: Mice lacking PCSK...

Oligonucleotide-directed triple-helix formation provides a rational means to interfere with genomic DNA targets and to direct modifications at specific sites. We have developed a new class of compounds that, at low concentrations, efficiently targets and damages double-stranded DNA specifically at the site where a triple-helical structure is formed...

To study the biological variation in the content of some persistent organic pollutants, viz hexachlorobenzene (HCB), alpha- and gamma-hexachlorocyclohexane (alpha- and gamma-HCH), and 1,1,1-trichloro-2,2-bis-(4-chlorophenyl)-ethane (DDT) were analysed in needles from Scots pine trees growing at an isolated peninsula south of Stockholm, Sweden. The...

The human adenine nucleotide translocator-2 promoter is activated by adjacent Sp1 activation elements centered at nucleotides −79 and −68 (Abox and Bbox, respectively), and is repressed by Sp1 bound to a GC element (Cbox) that lies adjacent to transcription start. Here, we address the mechanism of this unique Sp1-mediated repression using transfect...

Biogenesis of mammalian mitochondria requires the participation of both nuclear and mitochondrial genes. This thesis presents studies that characterize the common features of several nuclear encoded mitochondrial promoter genes and proposes the identity of factors regulating the transcription and responsible for coordinated, constitutive expression...

The p53 tumor suppressor protein inhibits the formation of tumors through induction of cell cycle arrest and/or apoptosis. In the present study we demonstrated that p53 is also a powerful inhibitor of human telomerase reverse transcriptase (hTERT), a key component for telomerase. Activation of either exogenous temperature-sensitive (ts) p53 in BL41...

The human cytochrome c(1) promoter is strongly activated in transfected Drosophila SL2 cells expressing exogenous human E2F1. Transfection-deletion experiments, DNase I protection by E2F1 and gel mobility-shift experiments locate E2F1 activation sites to two regions on either side of the transcription start site. Deletion of either region prevents...

The mammalian ATP/ADP translocator isoform-2 (ANT2) gene is growth-activated. Regulation of the gene appears to involve Spl, as an essential activator, and a suppressor through an Spl core element next to the transcription start. We show here that the proximal promoter also binds AP-2 strongly and specifically to two sites, one of which overlaps th...

To gain insight into the role of the general transcription factor, Sp1, in the expression of nuclear genes involved in mitochondrial biogenesis, we investigated Sp1 activation of the adenine nucleotide translocator 2, cytochrome c1, F1-ATPase beta subunit, and the mitochondria transcription factor (mtTFA) promoters transfected into Drosophila cell...

Thyroid hormone (T3) modulates the mRNA levels for cytochrome c and the adenine nucleotide translocator-2 (ANT2) in adult rat liver. Here we show that T3 activates expression of a reporter gene driven from the human cytochrome c1 and ANT2 promoters transfected into human choriocarcinoma JEG3 cells. By contrast, the human F1-ATPase beta-subunit prom...