Hydrogen Peroxide Induced Oxidative Damage on Mineral Density and Mechanical Properties of Bone

ABSTRACT Hydrogen peroxide is a common reactive oxygen species involved in the catalytic mechanism though it is toxic to cells due to its oxidative nature. This work investigates the effects of hydrogen peroxide induced oxidative damage on bone mineral density and mechanical properties of bone which is primarily a composite material composed primarily of collagen fibers and biominerals. Sheep leg bones were exposed to hydrogen peroxide for a week. Bone mineral density was measured by using dual energy X-ray absorptiometry. Compressive modulus tests were applied to bone in order to determine mechanical properties. Our study shows that the hydrogen peroxide induced oxidative stress has negative effects on bone mineral density and stiffness. We observed higher control curve slopes than that of hydrogen peroxide curves which account for lesser stiffness values in the exposed tissue (p<0.05)

Vesicouterina fistula: Youssef's syndrome

Vesico-uterin fistula is a rare type of fistulas and can be diagnosed frequently after surgery. First described by Youssef in 1957. Clasically findings are; cyclic haematuria without urinary incontinence and secondary amenorrhea. The patient was referred to our clinic for cyclic hematuria and she was diagnosed with vesicouterine fistula by radiological imaging methods and a cystoscopy procedure. Being a rare occurrence, this case was reported with a discussion of the relevant literature

Prolonged overexpression of PLK4 leads to formation of centriole rosette clusters that are connected via canonical centrosome linker proteins

Abstract Centrosome amplification is a hallmark of cancer and PLK4 is one of the responsible factors for cancer associated centrosome amplification. Increased PLK4 levels was also shown to contribute to generation of cells with centriole amplification in mammalian tissues as olfactory neuron progenitor cells. PLK4 overexpression generates centriole rosette (CR) structures which harbor more than two centrioles each. Long term PLK4 overexpression results with centrosome amplification, but the maturation of amplified centrioles in CRs and linking of PLK4 induced amplified centrosomes has not yet been investigated in detail. Here, we show evidence for generation of large clustered centrosomes which have more than 2 centriole rosettes and define these structures as centriole rosette clusters (CRCs) in cells that have high PLK4 levels for 2 consecutive cell cycles. In addition, we show that PLK4 induced CRs follow normal centrosomal maturation processes and generate CRC structures that are inter-connected with canonical centrosomal linker proteins as C-Nap1, Rootletin and Cep68 in the second cell cycle after PLK4 induction. Increased PLK4 levels in cells with C-Nap1 and Rootletin knock-out resulted with distanced CRs and CRCs in interphase, while Nek2 knock-out inhibited separation of CRCs in prometaphase, providing functional evidence for the binding of CRC structures with centrosomal linker proteins. Taken together, these results suggest a cell cycle dependent model for PLK4 induced centrosome amplification which occurs in 2 consecutive cell cycles: (i) CR state in the first cell cycle, and (ii) CRC state in the second cell cycle

Epidemiological, Clinical, and Laboratory Features of Children With COVID-19 in Turkey

Objectives: The aim of this study is to identify the epidemiological, clinical, and laboratory features of coronavirus disease 2019 (COVID-19) in children