Role of Active Site Residues on Catalytic Activity of Catalase with Oxidase Activity from Scytalidium Thermophilum

AbstractScytalidium thermophilum produces a catalase with phenol oxidase activity (CATPO) that catalyses the dismutation of hydrogen peroxide (H2O2) to dioxygen and water and also oxidizes several phenolic compounds in the absence of hydrogen peroxide. It comprises 717 amino acids with a 19 amino acid signal sequence, and a 17 amino acid prosequence. It is a homotetrameric protein of molecular mass 320 kDa and subunit molecular mass 80 kDa. Although catalases have been studied for many years, a peroxide independent oxidative activity of catalases has recently been recognized. There are a great number of reports available describing the structural and biochemical characterization of catalases. However basic questions related to substrate and product flow remain unanswered, particularly related to the oxidase activity. The goals of our current studies are to investigate the main and lateral channels known that connect the deeply buried active site to the exterior of the enzyme. We have introduced a number of mutations into these regions and analyzed their specific activities

Paget’s Disease Mimicking Bone Metastasis in a Patient with Neuroendocrine Tumor on 68Ga-DOTANOC PET/CT

Somatostatin (SST) is a neuropeptide present in neurons, endocrine cells, and a wide range of neuroendocrine tumors (NETs). 68Ga-DOTATOC, 68Ga-DOTANOC, and 68Ga-DOTATATE are current SST analogues used for PET/CT which bind to SST receptors expressed in NETs. These SST analogues have been used successfully for diagnosis of SST-expressing tumors with a more sensitive detection technique than conventional scintigraphy. However, there is a lack of clinical data on the differentiation between NETs and other malignant tumors or benign pathological conditions. Here, we report a case of Paget’s disease mimicking bone metastasis of NET on PET/CT due to increased 68Ga-DOTANOC uptake and review examples of similar cases in the literature

Evaluation of vertebral bone mineral density in scoliosis by using quantitative computed tomography

Purpose: Scoliosis is described as a lateral curvature of the spine. We aimed to evaluate bone mineral density (BMD) in patients with scoliosis by using quantitative computed tomography (QCT) and compare the BMD of idiopathic and congenital scoliosis patients. Material and methods: Forty-three patients aged 1 to 40 years with idiopathic, congenital, or neuromuscular scoliosis and 41 matched controls of the same sex and approximate age were included in the study. Measurements of BMD were performed by QCT analysis for each vertebral body from T12 to L5, and mean BMD was calculated for each case. Results: Twenty-two of the patients with scoliosis were idiopathic, 15 were congenital, four were neuromuscular, and two were neurofibromatosis. The mean BMD values of patients with scoliosis were significantly lower compared with the control group (106.8 ± 33.4 mg/cm3 vs. 124.9 ± 29.1 mg/cm3, p = 0.009). No significant difference in BMD values was found between idiopathic and congenital scoliosis patients (p > 0.05). Conclusions: This study illustrated that the vertebral body BMD values of the patients with scoliosis were significantly lower than those seen in the control group

Detection of α-Thalassemia by Using Multiplex Ligation-Dependent Probe Amplification as an Additional Method for Rare Mutations in Southern Turkey

α-thalassemia is the most common single gene disorder in the Cukurova Region in Turkey. It is therefore routinely screened, including premaritally, in our region. The heterogeneous molecular basis of the disease makes α-thalassemia mutation detection difficult and complex. Besides well established methods, multiplex ligation dependent probe amplification (MLPA) is known as an effective, simple and specific method for the detection and characterization of deletions and duplications. We employed MLPA testing to 30 patients with hematological parameters suggestive of α-thalassemia carrier status but was negative for α-thalassemia with conventional reverse dot blot hybridization (RDB). We found α-globin gene deletions in 3 out of 30 (10 %) patients with MLPA. We propose that MLPA can be used as a second tier test in addition to other techniques such as RDB to identify α-thalassemia carriers in high prevalence regions such as ours, thereby allowing clinicians to provide accurate genetic counselling

Effects of a fixed-payment method on demand for imaging tests in a university hospital

Background In 2006, a new medical payment framework such as fixed-payment method was implemented in Turkey and then cancelled 5 months later. The aim of this study was to explore the effects of this payment method on the demand for imaging tests