Helen Dimitriou

Helen Dimitriou
University of Crete | UOC · Medical School, Division of Mother & Child Health

Professor

About

118
Publications
10,142
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1,356
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Introduction
Helen Dimitriou currently works at the Medical School, Experimental Pediatrics, University of Crete. She does research- Cell & Molecular Biology- in Cancer, Infections and Climate Change.
Additional affiliations
February 1990 - March 2016
University of Crete
Position
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Publications

Publications (118)
Article
Full-text available
Oxidative stress is considered pivotal in the pathophysiology of sepsis. Oxidants modulate heat shock proteins (Hsp), interleukins (IL), and cell death pathways, including apoptosis. This multicenter prospective observational study was designed to ascertain whether an oxidant/antioxidant imbalance is an independent sepsis discriminator and mortalit...
Article
Objectives: To prospectively quantify at the community level changes in asthma symptom control and other morbidity indices, among asthmatic schoolchildren in response to coronavirus disease 2019 (COVID-19) lockdown measures. Methods: In Spring 2019 and Spring 2020, we prospectively assessed monthly changes in pediatric asthma control test (c-ACT...
Article
Background Individuals with type 1 diabetes (T1D) are at increased risk of infections from vaccine-preventable diseases. This study focuses on compliance of T1D patients to the recommended vaccination schedule, vaccination of their close contacts for influenza and on factors potentially contributing to vaccination program deviations. Methods The s...
Article
Background: The south-eastern Mediterranean experiences frequent desert dust storm events (DDS) that have been shown to be associated with adverse health effects. Aims: This study assessed the perceptions and practices towards DDS of local authorities and stakeholders from 3 countries in the region, Cyprus, Greece and Israel. Methods: Between...
Article
Full-text available
Between March and April 2020, Cyprus and Greece health authorities enforced three escalated levels of public health interventions to control the COVID-19 pandemic. We quantified compliance of 108 asthmatic schoolchildren (53 from Cyprus, 55 from Greece, mean age 9.7 years) from both countries to intervention levels, using wearable sensors to contin...
Article
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Sepsis is a dysregulated host response to infection related to devastating outcomes. Recently, interest has been shifted towards apoptotic and antiapoptotic pathobiology. Apoptosis is executed through the activation of caspases regulated by a number of antiapoptotic proteins, such as survivin. The survivin and caspases’ responses to sepsis have not...
Preprint
Full-text available
Between March and April 2020, Cyprus and Greece health authorities enforced three escalated levels of public health interventions to control the COVID-19 pandemic. We quantified compliance of asthmatic schoolchildren from both countries to intervention levels, using wearable sensors to continuously track personal location and physical activity. Cha...
Article
Background: Experimental data indicate that sepsis influences the mitochondrial function and metabolism. We aim to investigate longitudinal bioenergetic, metabolic, hormonal, amino-acid, and innate immunity changes in children with sepsis. Methods: Sixty-eight children (sepsis, 18; systemic inflammatory response syndrome [SIRS], 23; healthy cont...
Article
Full-text available
Objective: Mesenchymal Stromal Cells (MSC) have a supportive role in hematopoiesis and as components of the bone marrow microenvironment may present alterations during ALL and be affected by chemotherapeutic agents. We examined the biological and functional characteristics of MSC at ALL diagnosis and treatment and their effect on MSC qualitative p...
Article
Objectives: To examine whether the septic profiles of heat shock protein 72, heat shock protein 90α, resistin, adiponectin, oxygen consumption, CO2 production, energy expenditure, and metabolic pattern, along with illness severity, nutritional, and inflammatory indices, differ between adult and pediatric patients compared with systemic inflammator...
Article
Critical illness covers a wide variety of pathophysiological processes taking place in a severely ill or injured individual, leading to a diversity of functional defects, cellular dysfunctions and organ impairments. Especially, inflammatory response syndrome (SIRS), sepsis and septic shock are common conditions in an intensive care setting and are...
Conference Paper
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Introduction In addition to systemic hemodynamics, the management of neurocritically ill patients is often informed by neuromonitoring. In the absence of high-level evidence clinicians are often guided by personal and local expertise. Little is known about practices as they pertain to the use of such monitoring in patients with acute brain injury (...
Article
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Mammalian heat-shock-protein (HSP) 90α rapidly responses to environmental insults. We examined the hypothesis that not only serum HSP72 but also HSP90α is increased in the systemic inflammatory response syndrome (SIRS), severe-sepsis (SS), and/or sepsis (S) compared to healthy children (H); we assessed HSP90α relation to (a) multiple organ system f...
Article
Introduction: Nitric oxide was suggested to regulate p53-dependent expression of heat shock proteins and changes in cellular metabolism. Methods: Here we examined the longitudinal changes of NO metabolites, NO2 and NO3, ATP, a marker of mitochondrial function, and the expression of heat shock proteins (HSP)-72 and -90α in patients, adults and ch...
Conference Paper
Introduction: Systemic inflammation is associated with an excessive production of nitric oxide (NO), which interferes with a number of metabolic pathways, including mitochondrial ATP synthesis. Methods: We examined seventy-eight adult patients (severe sepsis (SS)/22; non-infectious systemic inflammatory response (SIRS)/23; healthy (H)/33). Energ...
Article
Introduction: SIRS (systemic inflammatory response syndrome) and sepsis are associated with increased oxidative stress. Oxidative stress activates endothelia, leads to adherence of leukocytes and induces oxidative modifications in membranes by lipid peroxidation. Biliverdin reductase (BVR) and heme oxygenase (HO) are important for the prevention o...
Article
The recognition of the role of Mesenchymal Stromal Cells (MSC) in hematopoiesis, as part of the bone marrow microenvironment, renewed the interest for cord blood (CB) ex vivo expansion as a source of HSC for transplantation. MSC from children are recognized to have different biological properties compared to the ones from adults. The current study...
Article
Full-text available
Extracellular heat shock proteins (HSP) act as inducers of interleukins (IL) and stimulants for immune cells during systemic inflammatory response syndrome (SIRS). Little is known about the alarming roles of extracellular HSP72 and HSP90α in the acute phase [1] of sepsis (S) or severe sepsis (SS). We determined serum HSP90α, HSP72 and neutrophil CD...
Article
Increased levels of asparagine synthetase (ASNS), an enzyme producing intracellular asparagine, have been implicated in the development of asparaginase resistance. The aim of this study was to assess ASNS mRNA and protein expression in bone marrow cell populations of children with acute lymphoblastic leukemia (ALL). Bone marrow mononuclear cells at...
Article
Full-text available
Mesenchymal stromal cells (MSCs) comprise a promising source for cellular therapy due to their ability to be readily isolated from various tissues and expand ex vivo. A unique property of these cells is the modulation of immune responses, making them attractive candidates for the treatment of autoimmune diseases. Recently, several clinical trials,...
Article
Full-text available
Background Critical illness constitutes a serious derangement of metabolism. The aim of our study was to compare acute phase metabolic patterns in children with sepsis (S) or severe sepsis/septic shock (SS) to those with severe traumatic brain injury (TBI) and healthy controls (C) and to evaluate their relations to neutrophil, lymphocyte and monocy...
Article
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Introduction Lipoproteins were shown to neutralize LPS and to exert direct anti-inflammatory actions. Neutrophil CD64-expression (nCD64) was shown to be an early inflammatory sign. Objectives To examine whether plasma concentrations of high (HDL)- or low (LDL)-density lipoproteins are related to nCD64, triglycerides, glucose, severity of illness (P...
Article
The mechanisms of immune tolerance to hepatitis B virus (HBV) in children infected perinatally or early in infancy still remain unclarified. We aimed to study the genetic variants of immune factors implicated in viral-host interaction in children who were born to HBV-positive mothers and who had different clinical outcome. Mannose-binding lectin ge...
Article
Umbilical cord blood (UCB) is a rich source of stem cells, the characterization and isolation of which requires specific stem cell markers and reliable and reproducible protocols. We assessed CD133 isolation in 39 UCB samples, using a commercial immunomagnetic cell-sorting protocol, and, because of its non-reproducibility, we applied optimized prot...
Data
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Article
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Transforming growth factor β (TGFβ) is a pluripotent cytokine promoting epithelial cell plasticity during morphogenesis and tumour progression. TGFβ binding to type II and type I serine/threonine kinase receptors (TβRII and TβRI) causes activation of different intracellular signaling pathways. TβRI is associated with the ubiquitin ligase tumor necr...
Article
Urine IL-8 concentrations are known to be elevated in urinary tract infection (UTI), as well as in vesicoureteral reflux (VUR) even in the absence of infection. In this study we further investigated urine IL-8 in infants with congenital anomalies of the kidneys and urinary tract and with antenatally diagnosed isolated pelvic dilatation. Urine IL-8...
Article
3705 Idiopathic thrombocytopenic purpura (ITP) or primary immune thrombocytopenia is one of the most common blood diseases as well as the commonest acquired bleeding disorder in childhood. Although the etiology of ITP is unclear, in the pathogenesis of the disease both environmental and genetic factors including polymorphisms of TNF-a, IL-10 and IL...
Article
Age-related changes that could affect the biologic features of mesenchymal stromal cells (MSC), such as a decrease in proliferation and osteoblast differentiation capacity and an increase of senescence markers and apoptosis, have been reported recently. The aim of this study was the evaluation of age-related characteristics and the correlation of a...
Article
The effect of recombinant human erythropoietin (rHuEPO) on the anemia of cancer was examined in 15 children with hematologic malignancies (group I) and solid tumors (group II), whose hemoglobin (Hb) was under the third percentile for sex and age. The response to rHuEPO was defined as an increase of Hb to above the 10th percentile following 8 weeks...
Article
Full-text available
Mesenchymal stromal cells (MSC) represent a novel cellular candidate in the field of transplantation and tissue regeneration. Their clinical application requires their in vitro expansion. The aim of this study was to assess the effect of conditions that would favour apoptosis, and of long-term expansion, on the characteristics of MSC from children....
Article
Full-text available
Mesenchymal stromal cells (MSCs) have attracted considerable interest in both the scientific and clinical fields. In order to obtain a sufficient cell number for application, their in vitro expansion is necessary, but during this process their characteristics may be altered and cells may acquire oncogenic properties. We have investigated properties...
Article
The opioid system plays a major role in immunomodulation, while its action on cells of the immune system may be opioid receptor-mediated or not. Opioid effects on B-lymphocytes are considered as indirect, attributed to an interplay between distinct cell populations. The aim of the present study was to investigate whether opioid agonists (morphine,...
Article
In the past few years, intensive research in the understanding of the biologic characteristics of the mesenchymal stromal cells has already led to some early clinical applications. The aim of this review is to summarize the latest information from basic science advances and the outcome of their use in clinical practice with a particular focus in pe...
Article
Stem cells are the self-renewing progenitors of several body tissues and are classified according to their origin and their ability to differentiate. Current research focuses on the potential uses of stem cells in medicine and how they can provide effective treatment for a range of diseases. This approach has resulted in the field of medical practi...
Article
A combined strategy using bioluminescence imaging, bone densitometry and histology was used to analyze the bone regeneration capacity of human bone marrow (hBMSC) and adipose tissue (hAMSC) mesenchymal stem cells, seeded in an osteoconductive arginine-glycine-aspartate (RGD) crosslinked hydrogel scaffold, implanted in a mouse calvarial bone defect....
Article
Cord blood (CB) has long been regarded as an easily accessible source of hematopoietic progenitors suitable for transplantation, but its efficiency as a source of mesenchymal stromal cells (MSC) remains controversial. The aim of this study was to assess CB as a potential source of MSC, to determine the optimal culture requirements for CB MSC expans...
Article
Mesenchymal stromal cells (MSC) have become the focus of cellular therapeutics but little is known regarding bone marrow (BM) MSC derived from children. As MSC constitute part of BM stroma, we examined their properties in children with hematologic diseases. BM MSC from children with non-malignant hematologic disorders and acute lymphoblastic leukem...
Article
Stem cells are the self-renewing progenitors of several body tissues and are classified according to their origin and their ability to differentiate. Current research focuses on the potential uses of stem cells in medicine and how they can provide effective treatment for a range of diseases. This approach has resulted in the field of medical practi...
Article
Umbilical cord blood (UCB) is a rich source of stem cells. Characterisation of stem cell subpopulations residing in UCB requires specific stem cell markers and reliable and reproducible protocols. We assessed the feasibility of CD133 positive cells’ isolation using immunomagnetic cell sorting protocols. The separation was based on the manufacturer’...
Article
Mesenchymal stromal cells (MSC) have attracted considerable interest in both the scientific and clinical fields because of their potential to regenerate tissues and support hematopoiesis. Although laboratory isolation of MSC is established, the lack of an MSC specific marker and their low frequency in bone marrow necessitates their in vitro expansi...
Article
In the last three years we have prepared and studied the polar methanolic extract PMF, of the herb Hypericum perforatum L, and studied as a new, alternative photosensitizing substance for PDT. Hypericum perforatum L., as well as PMF, contains a number of naphthodianthrone derivatives (hypericins), such as hypericin and pseudohypericin, as its main...
Article
Cytokines are involved both in the acute response during pyelonephritis and in the progression to renal scarring. The aim of the present study was to assess the pro-inflammatory interleukin-6 (IL-6) and the anti-inflammatory pro-fibrotic transforming growth factor-beta1 (TGF-beta) in very young infants with pyelonephritis. Serum and urine concentra...
Article
Human cord blood has been successfully used as an alternative source of hematopoietic stem cells suitable for transplantation. The aim of this study was to assess the impact of gestational age and the mode of delivery on cord blood hematopoietic stem/progenitor cell characteristics. The mode of delivery does not seem to affect either the replating...
Article
Cyclin-dependent kinases (CDKs) and cyclins, their regulatory subunits, govern cell-cycle progression in eukaryotic cells. Kip1/p27 is the main cyclin-dependent kinase inhibitor, which arrests cell division inhibiting G1-S transition. Kip1/p27 seems to play a critical role in the pathogenesis of several human malignancies and its lower expression h...
Article
Vesicoureteral reflux (VUR) is a common finding in children presenting with urinary tract infection (UTI) and prenatally diagnosed urinary tract dilatation and in relatives of index patients. Children with VUR are at risk for ongoing renal damage with subsequent infections. Detecting VUR and renal scarring currently depends on imaging modalities wi...
Article
Opioid agonists have been shown to exert an inhibitory action on a number of malignant and non-malignant cell types. However, there are no reports dealing with their effect on hemopoietic progenitors. Based upon our previous experience of opioid agonists we examined whether opioids could interfere with the growth of CFU-GM from CD133(+) cord blood...
Article
Mesenchymal Stem Cells (MSCs) are multipotent progenitor cells within the bone marrow (BM) capable of differentiating into various tissue specific cells including adipocytes (A), osteoblasts (O), chondrocytes (C), myoblasts, hepatocytes and possibly neuronal tissue. MSCs form an integral part of the BM stroma, have immunomodulatory functions and pl...
Article
Autologous bone marrow transplantation is a therapeutic modality that increases the survival rates for children with malignancies with poor prognosis but relapse rates are high and attributed partially to the existence of residual malignant cells. Photodynamic treatment (PDT) has been developed among purging strategies. We investigated the effect o...
Article
Full-text available
Angiogenesis was estimated in childhood acute lymphoblastic leukemia (ALL) by the use of a novel morphometric method. This was compared with the widely used one of microvessel density (MVD). Bone marrow biopsies were evaluated by immunostaining with anti-Factor VIII related antigen (FVIIIRAg). Angiogenesis was calculated as volume corrected microve...
Article
We are reporting elsewhere, the promising photodynamic effect of Hypericum perforatum L. extract (PMF) against T24, NBT-II tumor bladder cells, and HL-60 leukemic cells (using 630nm, and 530nm laser light respectively). The main advantages of the extract as a photosensitizer are its low cost, extensive availability, adequate solubility, minimal tox...