Search results for "Transformation"
showing 10 items of 1634 documents
Biosynthesis and transformation of 20α 21-dihydroxycholesterol by rat adrenal preparations
1979
Abstract The biosynthesis of [ 3 H]-20α, 21 dihydroxycholestderol from [ 3 H]-20α-hydroxycholesterol and its transformation to [ 3 H]-21-hydroxypregnenolone by rat adrenal preparations has been demonstrated. 20α-Hydroxycholesterol was transformed to 20α, 21-dihydroxycholesterol by microsomal preparations in the presence of NADPH and 20α-21-dihydroxycholesterol was metabolized to 21-hydroxypregnenolone by mitochondrial preparations in the presence of a NADPH-generating-system. Comparison of the Michaelis-Menten-Kinetics of the steps “20α, 21-dihydroxycholesterol → 21-hydroxycholesterol” and “20α-hydroxycholesterol → pregnenolone” revealed that both compounds behaved as analogue substrates of…
: Med Oral Patol Oral Cir Bucal
2017
Background Oral cancer is a public health issue worldwide. Oral potentially malignant disorders (OMPDs) are lesions of the oral mucosa that are predisposed to malignant transformation. The mainstay of OMPDs treatment around the world is now the carbon dioxide (CO2) laser but the reported recurrence and malignant transformation rates vary widely in the literature. We aimed to estimate the recurrence and the malignant transformation rates of OPMDs treated with CO2 laser at the University Hospital of Bordeaux, in France, from 2010 to 2014, and to identify associated factors with recurrence or malignant transformation. Material and Methods We conducted a retrospective study in patients with a m…
Cholesterol levels and risk of hemorrhagic transformation after acute ischemic stroke.
2011
<i>Background:</i> The association between cholesterol levels and hemorrhagic transformation (HT) is still controversial. Studies investigating this issue are influenced by treatments as some are characterized by a higher risk of HT. The aim of our study was to evaluate, in a hospital-based series of patients not treated with thrombolysis, the relationship between cholesterol levels and HT. <i>Methods:</i> We retrospectively collected information about total cholesterol (TC) and low-density lipoprotein cholesterol (LDLC) levels at admission in a consecutive series of 240 patients with anterior ischemic stroke (IS). The TC and LDLC levels were arranged in 3 groups acc…
Regulation of cell-to-cell communication in non-tumorigenic and malignant human prostate epithelial cells.
2002
BACKGROUND Gap-junction-mediated intercellular communication (GJIC) is required for normal development and tissue homeostasis. However, the role of GJIC in human prostate carcinogenesis and progression remains ill-defined. METHODS The ability of hormones, anti-hormones, and the anti-hypertensive drug, forskolin, to restore GJIC in non-tumorigenic (RWPE-1 and PWR-1E) and malignant (RWPE-2, LNCaP, DU-145) human prostate epithelial cell lines, was examined by Scrape-Loading/Dye Transfer (SL/DT) and Fluorescence Recovery After Photobleaching (FRAP) methods using an Ultima laser cytometer. RESULTS Results from both assays show that PWR-1E, RWPE-2, LNCaP, and DU-145 cells have weak or absent GJIC…
Malignant transformation of oral leukoplakia: a multicentric retrospective study in Brazilian population
2020
Background Among the oral potentially malignant disorders, leukoplakia stands out as the most prevalent. The purpose of this study was to analyse the clinical-pathological features of oral leukoplakia in groups of patients from three major pathology centers in two different regions of Brazil, in order to determine which factors would be associated to the clinical risk of malignant transformation. Material and Methods A total of 148 patients was analyzed, and data regarding gender, age, site, classification of the clinical subtype, harmful habits such as use of tobacco and alcohol, time of evolution and presence of dysplasia were collected. The association between risk factors and malignant …
Comparison of enzyme phenotypes in human bladder tumours and experimentally induced hyperplastic and neoplastic lesions of the rat urinary bladder. A…
1988
The expression of a number of enzymes involved in drug metabolism, membrane function etc. was compared in hyperplastic and neoplastic lesions of the rat bladder and in human bladder tumours. Transitional cell carcinomas (TCC) in both rat and Man were characterized by decreased alkaline phosphatase (ALP) and increased gamma-glutamyl transpeptidase (GGT), beta-glucuronidase (beta-G1), succinate dehydrogenase (SD) and glucose-6-phosphate dehydrogenase (G6PD) activities. In addition, binding for antibodies specific for different cytochrome P-450 species (UT50, PB3a, MC1, MC2) and microsomal epoxide hydrolase (mEHb) was elevated in both murine and human tumours. Comparison of the enzyme phenotyp…
Long-term expression of differentiated functions in hepatocytes cultured in three-dimensional collagen matrix.
1998
Hepatocytes entrapped in collagen gel and cultured in serum-free conditions survived longer than cells cultured on plastic (5 days vs. 3 weeks), showed fewer signs of early cell senescence (no increase in c-fos oncoprotein expression), and maintained the expression of differentiated hepatic metabolic functions over a longer period of time. Cells cultured in collagen gels retained their ability to respond to hormones. The insulin-stimulated glycogen synthesis rate remained fairly constant during 18 days in culture (between 5.4 +/- 0.37 and 9 +/- 2.7 nmol glucose/h/microg DNA). Collagen-cultured hepatocytes recovered glycogen stores to levels similar to those found in liver, or in hepatocytes…
Sympathetic Nerve Stimulation on the perfused rat heart. Affinities of N-methylatropine and pirenzepine at pre- and postsynaptic muscarine receptors.
1982
Rat isolated hearts with the sympathetic nerves attached were perfused with (-)-3H-noradrenaline in order to label the storage vesicles of the adrenergic nerves. Release was induced either by electrical stimulation of the nerves (3 Hz, 1 min) or by perfusion with high K+ solution (54 mM). The overflow of 3H-noradrenaline and its metabolites was determined by liquid scintillation counting after separation of the compounds by column chromatography. The experimental conditions ensured a minor contribution of 3H-metabolites to the evoked total tritium overflow. The release of 3H-noradrenaline evoked by nerve stimulation or high K+ solution was decreased in the presence of the muscarinic agonist…
Frequency and determinants for hemorrhagic transformation of cerebral infarction.
2009
<i>Background:</i> Frequency and associated risk factors for hemorrhagic transformation (HT), a worrying complication of ischemic stroke (IS), are not clearly defined. Our aim was to estimate the overall frequency and risk factors for HT in a hospital-based population. <i>Methods:</i> A retrospective review of medical records of patients discharged from our department during the period 2004–2006 with a diagnosis of anterior IS. Demographic, clinical and hematological information was collected. Uni- and multivariate logistic regression analyses were used to estimate risk for spontaneous HT. <i>Results:</i> We included 240 patients (125 males, 52%), mean ag…
Essential thrombocythemia terminating in pure erythroleukemia
2004
Transformation into acute leukemia is a rare event in essential thrombocythemia (ET). The blasts are usually of myeloid, rarely of megakaryoblastic differentiation. We present the case of a patient with pure erythroleukemia after a nearly 10-year course of ET, which was treated with hydroxyurea. The patient, a 58-year-old male, presented with an elevated thrombocyte count (926,000/μL) and normal values of hemoglobin and leukocytes. After 10 years of therapy with hydroxyurea, the patient developed acute leukemia of solely erythroid differentiation. Chemotherapy with cytarabine and daunorubicin resulted in incomplete remission. The patient died 2 months after diagnosis of acute erythroleukemi…