Publications by authors named "Yannis L Loukas"

Breast cancer (BC) is among the most commonly diagnosed cancers. Besides mammography, breast ultrasonography and the routinely monitored protein markers, the variations of small molecular metabolites in blood may be of great diagnostic value. This study aimed to quantify specific metabolite markers with potential application in BC detection.

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Dried blood spot (DBS) microsampling is extensively employed in newborn screening (NBS) and neonatal studies. However, the impact of variable neonatal hematocrit (Ht) values on the results can be a source of analytical error, and the use of fixed Ht for calibration (Ht) is not representative of all neonatal subpopulations. A computational approach based on neonatal demographics was developed and implemented in R language to propose a strategy using correction factors to address the Ht effect in neonatal DBS partial-spot assays.

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The Homologous Recombination Deficiency (HRD) Score, determined by evaluating genomic instability through the assessment of loss of heterozygosity (LOH), telomeric allelic imbalance (TAI), and large-scale state transitions (LST), serves as a crucial biomarker for identifying patients who might benefit from targeted therapies, such as PARP inhibitors (PARPi). This study aimed to investigate the efficacy of HRD testing in high-grade serous ovarian carcinoma, tubal, and peritoneal cancer patients who are negative for somatic BRCA1 and BRCA2 mutations and to evaluate the impact of HRD status on Bevacizumab and PARPi therapy response. A cohort of 100 Romanian female patients, aged 42-77, was initially selected.

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Amino acid neurotransmitters, including glutamate, phenylalanine, tyrosine, alanine, and glycine, underlie the majority of the excitatory and inhibitory neurotransmission in the nervous system, and acute exercise has been shown to modulate their concentrations. We aimed to determine whether any correlation exists between the above-mentioned amino acid blood concentrations and the neuropsychological performance after an acute exercise intervention. Sixty basketball players were randomly assigned to one of two experimental conditions: exercise or inactive resting.

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Objectives: Medium-chain (MCA) and long-chain acylcarnitine (LCA) blood concentrations play a significant role in the fatty acid (FA) oxidation process, especially during the first days of life. Identification of their abnormal concentrations, expanded newborn screening, can lead to the diagnosis of FA oxidation disorders. This study aimed to demonstrate MCA and LCA concentrations in Dried Blood Spots (DBS) of full-term breastfed infants, in relation to their birth weight (BW) perinatally.

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Essential, non-essential and conditionally essential amino acid blood concentrations play a critical role in newborns. We aimed to quantitate most of these amino acids in the blood of full-term breastfed infants, perinatally and correlate the obtained values with their birth weight. Breastfed full-term infants ( = 12,000; 6000 males, 6000 females) with birth weight 2000-4000 g were divided into 4 equal groups: Group A, 2000-2500 g; B, 2500-3000 g; C, 3000-3500 g and D, 3500-4000 g.

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Background: Free carnitine (C0) and short chain acylcarnitine (SCA) blood concentrations play a significant role in fatty acid oxidation process during the first days of life. The aim of this study was to demonstrate C0 and SCA concentrations in Dried Blood Spots (DBS) of full term breastfed infants in relation to their birth weight (BW) perinatally.

Methods: Breastfed full term infants (n = 12,000, 6000 males, 6000 females) with BW 2000-4000 g were divided into 4 equal groups: Group A, 2000-2500 g, B 2500-3000 g, C 3000-3500 g and D 3500-4000 g.

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Background The amino acids glutamine plus glutamate, phenylalanine and tyrosine are implicated in neurotransmission. We aimed to evaluate these amino acid blood concentrations in full-term breastfed infants with different birth weight (BW) perinatally. Methods Breastfed full-term infants (n = 6000, males 3000, females 3000) BW 2000-4000 g were divided into four equal groups.

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Objective: Cystic fibrosis (CF) is a multisystemic inherited disease. The aim of this study was to determine free carnitine (FC) and acylcarnitine concentrations in CF newborns with various mutations of the gene perinatally.

Study Design: FC/acylcarnitines were determined in dried blood spots via liquid chromatography-tandem mass spectrometry (LC-MS/MS) on the third day of life of full-term normal ( = 50) and CF ( = 28) newborns.

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The establishment of expanded newborn screening (NBS) not only results in the early diagnosis and treatment of neonates with inborn errors of intermediary metabolism disorders (IEMDs) but also helps the affected females to reach the reproductive age under medical and dietetic support, as well as to give birth to normal infants. In this review, we aimed to focus on laboratory investigation tests, dietetic management and medical support for most known IEMD pregnant and lactating women, such as those suffering from aminoacidopathies, carbohydrate metabolic diseases and fatty acid (FAO) oxidation disorders.

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Background & Aims: Pregnancy is characterized by a complexity of metabolic processes that may impact fetal health and development. Women's nutrition during pregnancy and lactation is considered important for both mother and infant. This review aims to investigate the significant role of fatty acids and carnitine during pregnancy and lactation in specific groups of pregnant and lactating women.

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Background Arginine family amino acids (AFAAs) include glutamine (Gln) plus glutamate (Glu), ornithine (Orn), proline (Pro), citrulline (Cit) and arginine (Arg). We aimed to quantitate these amino acids in the blood of full-term infants in relation to their birth weight (BW) perinatally. Methods Breastfeeding full-term infants (n = 2000, 1000 males, 1000 females) with a BW of 2000-4000 g were divided into four equal groups: group A, 2000-2500 g; B, 2500-3000 g; C, 3000-3500 g and D, 3500-4000 g.

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Very recently, it was reported that a patient with classical galactosemia and a very high intelligence quotient (IQ) score obtained a university degree. In the present study, two siblings with classical galactosemia (homozygous for Q188R mutation) received upper normal IQ scores when tested with psychometric tools. Additionally, the same IQ scores were determined in their healthy brother when tested at the same age.

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Phenylalanine hydroxylase (PAH) deficiency, commonly named phenylketonuria (PKU) is a disorder of phenylalanine (Phe) metabolism inherited with an autosomal recessive trait. It is characterized by high blood and cerebral Phe levels, resulting in intellectual disabilities, seizures, etc. Early diagnosis and treatment of the patients prevent major neuro-cognitive deficits.

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Pregnancy is characterized by a complexity of metabolic processes that may impact fetal development and infant health outcome. Normal fetal growth and development depend on a continuous supply of nutrients the placenta. The placenta transports, utilizes, produces, and interconverts amino acids (AAs).

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A novel Liquid Chromatography-tandem mass spectrometry (LC-MS/MS) method is presented for the quantitative determination of two potential genotoxic impurities (PGIs) in rabeprazole active pharmaceutical ingredient (API). In order to overcome the analytical challenges in the trace analysis of PGIs, a development procedure supported by Quality-by-Design (QbD) principles was evaluated. The efficient separation between rabeprazole and the two PGIs in the shortest analysis time was set as the defined analytical target profile (ATP) and to this purpose utilization of a switching valve allowed the flow to be sent to waste when rabeprazole was eluted.

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A sensitive Liquid Chromatography tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantitative analysis of three potential genotoxic impurities (318BP, M9, S5) in meropenem Active Pharmaceutical Ingredient (API). Due to the requirement for LOD values in ppb range, a high concentration of meropenem API (30mg/mL) had to be injected. Therefore, efficient determination of meropenem from its impurities became a critical aim of this study, in order to divert meropenem to waste, via a switching valve.

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Background: Deficiencies of galactokinase (GALK) and UDP-epimerase (GALE) are implicated with galactose metabolic disorders. The aim of the study was the identification of mutations in GALK and GALE genes and clinical evaluation of patients.

Methods: Five patients with GALK and five with GALE deficiency were picked up via the Neonatal Screening Program.

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Classical galactosaemia is an inborn error of metabolism due to the deficiency of the enzyme galactose-1-phosphate uridylyltransferase (GALT). The aim of the study was to identify the underlying mutations in Greek patients with GALT deficiency and evaluate their psychomotor and speech development. Patients with GALT deficiency (n = 17) were picked up through neonatal screening.

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A fully automated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of omeprazole in human plasma. Utilization of 96-well plates and robotic liquid handling workstations, rendered the whole procedure very fast, compared to the manual respective procedure of Liquid-Liquid Extraction (LLE). Sample analysis was performed by reversed phase LC-MS/MS, with positive electrospray ionization, using multiple reaction monitoring (MRM).

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Purpose: To evaluate ex vivo the possible difference in corneal cross-linking (CXL) biomechanical effect of different ultraviolet-A (UV-A) irradiances.

Methods: The study involved 25 human donor corneas, randomly allocated to 5 groups (n = 5 each). CXL was applied with UV-A irradiances of 3, 9, 18, 30, and 45 mW/cm2, maintaining equal cumulative energy dose of 5.

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In the current study, a rapid and sensitive LC-QTOF-MS/MS method for the determination of brinzolamide in dried blood spots (DBS) was developed and validated. This novel sample collection, storage and transfer technique was suitable for analyzing a drug with high distribution into red blood cells and negligible plasma levels. The method included an isocratic mobile phase consisting of methanol and 10mM ammonium formate (90:10, v/v) and detection in positive electrospray mode (ESI+).

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