Publications by authors named "Ozen Ozensoy-Guler"

As one of the most common solid pediatric cancers, Neuroblastoma (NBL) accounts for 15% of all of the cancer-related mortalities in infants with increasing incidence all around the world. Despite current therapeutic approaches for NBL (radiotherapies, surgeries, and chemotherapies), these approaches could not be beneficial for all of patients with NBL due to their low effectiveness, and some severe side effects. These challenges lead basic medical scientists and clinical specialists toward an optimal medical interventions for clinical management of NBL.

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The ongoing Covid-19 is a contagious disease, and it is characterised by different symptoms such as fever, cough, and shortness of breath. Rising concerns about Covid-19 have severely affected the healthcare system in all countries as the Covid-19 outbreak has developed at a rapid rate all around the globe. Intriguing, a clinically used drug, acetazolamide (a specific inhibitor of carbonic anhydrase, CA, EC 4.

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Among the diagnostic techniques for the identification of tumour biomarkers, the liquid biopsy is considered one that offers future research on precision diagnosis and treatment of tumours in a non-invasive manner. The approach consists of isolating tumor-derived components, such as circulating tumour cells (CTC), tumour cell-free DNA (ctDNA), and extracellular vesicles (EVs), from the patient peripheral blood fluids. These elements constitute a source of genomic and proteomic information for cancer treatment.

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Head and neck cancer (HNC) is one of the most common malignancies in the world. HNC is a group of cancers that starts in the mouth, nose, throat, larynx, sinuses, or salivary glands. According to this section of the body parts; induction of cancer can be associated with CO and oxidative stress.

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In this paper, we reviewed the purification and characterization methods of the α-carbonic anhydrase (CA, EC 4.2.1.

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Four series of sulfonamides incorporating chromone moieties were synthesized and assessed for their cytotoxic activity against MCF-7 and A-549 cell lines, considering the fact that some of these tumors overexpress isoforms of carbonic anhydrase (CA, EC 4.2.1.

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  • A new affinity gel using L-Tyrosine was developed for purifying bovine testicular hyaluronidase (BTH) through a method involving cyanogen bromide-activated Sepharose-4B with m-Anisidine as a ligand.
  • The purification process achieved a yield of 16.95% and a high purity level of 881.78%.
  • Kinetic analysis showed that the Michaelis constant (K(M)) for BTH was 2.23 mM and the maximum reaction rate (V(Max)) was 19.85 U/mL, with gibberellic acid identified as the strongest inhibitor of the enzyme among tested chemicals.
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  • A preliminary study investigates new cerium vanadate derivatives as inhibitors of xanthine oxidase (XO), an enzyme linked to various health issues like gout and liver damage.
  • The study highlights the potential benefits these novel agents may offer compared to allopurinol, the standard XO inhibitor.
  • A critical overview is presented, discussing the efficacy and safety profiles of the new inhibitors in relation to existing treatment options.
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  • The study introduces a new affinity gel made from EUPERGIT C250L that utilizes etylenediamine arms to enhance binding efficiency of a specific ligand for purifying α-carbonic anhydrases (CAs).
  • The gel is modified by incorporating 4-isothiocyanatobenzenesulfonamide, resulting in a thiourea-based structure with inhibitory effects on CAs.
  • The affinity gel successfully purified both bovine and human carbonic anhydrase with notable purification folds of 181-fold and 184-fold, respectively, under optimal conditions of 15°C and ionic strength of 0.3.
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  • Mycosis fungoides (MF) is the most common type of cutaneous T-cell lymphoma, but little is known about the enzyme activities of catalase (CAT), carbonic anhydrases (CA), and xanthine oxidase (XO) in MF patients.
  • A study compared the enzyme activities of 32 MF patients to 26 healthy controls, revealing that CAT and CA activities were significantly lower in MF patients (p < 0.001), while XO activity showed no significant difference (p = 0.601).
  • The researchers suggest that measuring these enzyme levels could serve as a useful diagnostic tool for mycosis fungoides.
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Serum paraoxonase (PON1) is a high-density lipoprotein (HDL)-associated enzyme that protects lipoproteins, both low-density lipoprotein (LDL) and HDL, against oxidation, and is considered as an antioxidative/anti-inflammatory component of HDL. In this study, PON1 was purified from bovine serum by ammonium sulfate precipitation and hydrophobic interaction chromatography on sepharose-4B-l-tyrosine-1-napthylamine. It was then immobilized on an unmodified Eupergit® C 250 L support.

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A series of phenols incorporating tertiary amine and trans-pyridylethenyl-carbonyl moieties were assayed as inhibitors of the β-carbonic anhydrase (CA, EC 4.2.1.

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Serum paraoxonase 1 (PON1) was purified from bovine serum using hydrophobic interaction chromotography on Sepharose 4B-coupled l-tyrosine 1-naphthylamine gel, and monitored by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Paraoxonase enzyme was immobilized using different ratios of glutaraldehyde and the maximum activity was observed with 7% glutaraldehyde. The effects of inhibition by Mn(+2), Co(+2) and Cu(+2) heavy metals on the immobilized and free enzyme activities were studied.

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  • The β-carbonic anhydrase (scCA) from the yeast Saccharomyces cerevisiae efficiently catalyzes the conversion of CO(2) to bicarbonate, with high activity rates (k(cat) of 9.4 x 10(5) s(-1)).
  • Inhibition studies identified bromide, iodide, and various sulfonamides as potent inhibitors, particularly those with specific chemical substitutions yielding K(I) values ranging from 0.976 to 654 nM.
  • Findings suggest that understanding scCA's inhibition and activation mechanisms can inform the development of antifungal drugs targeting related pathogens due to the presence of the Nce103 gene in those organisms.
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Site-directed mutagenesis has been used to change one amino acid residue considered non essential (Phe91Asn) to catalysis in carbonic anhydrase (CA, EC 4.2.1.

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  • The polyphenol oxidase (LsPPO) enzyme from the wild edible mushroom Lactarius salmonicolor was effectively purified for further study.
  • The enzyme showed varying activity levels and optimal conditions (pH 4.5-11.0 and temperatures of 5-50 degrees C) for different substrates, with specific kinetic values recorded for catechol, 4-methylcatechol, and pyrogallol.
  • Several classical inhibitors were tested, revealing L-tyrosine as the most potent, while sulfosalicylic acid unexpectedly acted as an enzyme activator.
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