Search results for "Paraffin"
showing 10 items of 48 documents
Enantioselective addition of nitromethane to α-keto esters catalyzed by copper(ii)–iminopyridine complexes
2008
The copper complex of a chiral iminopyridine easily prepared from (R)-(-)-fenchone and picolylamine catalyzes the enantioselective Henry (nitroaldol) reaction between nitromethane and alpha-keto esters. Good yields and modest to good enantioselectivities are obtained for a wide range of alpha-keto esters, bearing aromatic, alkyl or alkenyl groups attached to the ketone carbonyl group.
Occurrence of Spontaneous Cortical Spreading Depression Is Increased by Blood Constituents and Impairs Neurological Recovery after Subdural Hematoma …
2019
Acute subdural hemorrhage (ASDH) is common and associated with severe morbidity and mortality. To date, the role of spontaneous cortical spreading depression (sCSD) in exaggerating secondary injury after ASDH, is poorly understood. The present study contains two experimental groups: First, we investigated and characterized the occurrence of sCSD after subdural blood infusion (300 μL) via tissue impedance (IMP) measurement in a rat model. Second, we compared the occurrence and influence of sCSD on lesion growth and neurological deficit in the presence and absence of whole blood constituents. In the first experimental group, three IMP traits could be distinguished after ASDH: no sCSD, recurre…
Distribution patterns in glycoconjugate expression during the development of the rat palate.
1994
The distribution of complex carbohydrate structures during the embryonic development of the rat palate was analysed by examining lectin-binding patterns in serial paraffin and cryostat sections. With few exceptions, the binding patterns showed a general increase in lectin receptors in the more developed stages of palatogenesis. High mannose oligosaccharides were especially amplified during development. Terminal fucose molecules were not expressed. In contrast, terminal sialic acid molecules were ubiquitously distributed in epithelial and mesenchymal tissues. Non-sialylated terminal N-acetylglucosamine was specifically restricted to evolving bone matrix. Before palatal fusion, quantitative b…
Blood constituents trigger brain swelling, tissue death, and reduction of glucose metabolism early after acute subdural hematoma in rats
2009
Outcome from acute subdural hematoma is often worse than would be expected from the pure increase of intracranial volume by bleeding. The aim was to test whether volume-independent pathomechanisms aggravate damage by comparing the effects of blood infusion with those of an inert fluid, paraffin oil, on intracranial pressure (ICP), cerebral perfusion pressure (CPP), local cerebral blood flow (CBF), edema formation, glucose metabolism ([18F]-deoxyglucose, MicroPET), and histological outcome. Rats were injured by subdural infusion of 300 μL venous blood or paraffin. ICP, CPP, and CBF changes, assessed during the first 30 mins after injury, were not different between the injury groups at most …
Prognostic indicators for squamous cell carcinoma of the oral cavity: a clinicopathologic correlation.
1997
Fifty-three patients with T1 squamous cell cancer of the floor of mouth and ventral surface of the tongue with a known clinical outcome were retrospectively analyzed and arbitrarily divided into "aggressive" and "nonaggressive" groups based on their clinical behavior. Various host and tumor factors were then evaluated in an attempt to determine whether the tumor behavior could have been predicted. The paraffin-embedded tumor specimens were evaluated for tumor differentiation, tumor thickness and tumor invasion, microvessel density, and p53 expression. In addition, a composite morphologic grading score was obtained by combining cell differentiation, nuclear polymorphism, mitosis activity, de…
Cell death and oxidative stress in gliomas.
1999
In gliomas, apoptosis and necrosis are determined by a number of promoting and inhibiting factors including oxidative cell stress mediated by nitric oxide synthases (NOS) and reduced by superoxide dismutases. Therefore, in 46 gliomas (including astrocytomas, oligodendrogliomas, oligo-astrocytomas, and glioblastomas), the relationship of apoptosis and necrosis and the expression of apoptosis-promoting (p53, bax, Fas, Fas-L) and inhibiting (bcl-2) factors as well as of different isoforms of NOS (NOSb, NOSe, NOSi) and manganese superoxide dismutase (MnSOD) were studied. Apoptosis was measured in situ by the TUNEL method while expression profiles of apoptosis-related and oxidative stress-associ…
Activation of propane 2-nitronate to a genotoxicant in V79-derived cell lines engineered for the expression of rat hepatic sulfotransferases
1999
2-Nitropropane (2-NP) is a genotoxic hepatocarcinogen in rats. The genotoxicity of the compound has been attributed to a sulfotransferase-mediated formation of DNA-reactive species from the anionic form of 2-NP, propane 2-nitronate (P2N). Several observations have suggested that sulfotransferases (SULTs) 1A1 and/or 1C1 may be important in the activation of P2N to a genotoxicant in rat liver, but a definite proof is lacking. In order to identify the sulfotransferase(s) of rat liver that are capable of activating P2N, we have investigated the genotoxicity of P2N in various V79-derived cell lines engineered for expression of individual forms of rat hepatic sulfotransferases. Genotoxicity was a…
Dietary lycopene decreases the initiation of liver preneoplastic foci by diethylnitrosamine in the rat
1997
To test whether carotenoids can modulate the initiation of liver preneoplasia by diethylnitrosamine (DEN) or by 2-nitropropane (2-NP) in a sequential protocol of hepatocarcinogenesis, male weanling rats were fed for three or four weeks (respectively) diets containing beta-carotene, canthaxanthin, astaxanthin, or lycopene (300 mg/kg diet) or an excess of vitamin A (15,000 retinol equivalents/kg diet) or were treated intraperitoneally with 3-methylcholanthrene. During this period, all rats were injected intraperitoneally with the initiator carcinogen, either 2-NP (6 times at 100 mg/kg body wt) or DEN (once at 100 mg/kg body wt). Three weeks after the termination of carotenoid or vitamin A fee…
Effect of surfactants and drying rate on barrier properties of emulsified edible films
2007
Summary The effects of globule size, nature and concentration of surfactant, and drying duration of water vapour transmission rate and tensile strength of emulsified edible barriers containing methylcellulose and paraffin wax, were measured. of the six surfactants tested, 0.6% purified glycerol monostearate (GMS) produced films with the lowest water vapour transmission rates and the highest mechanical resistance. Longer drying times of film-forming emulsions produced better barrier and mechanical properties. Control of the film forming emulsion stability allowed the reduction of the water vapour transfer rate by an order of magnitude.
Improvement of the butyl methacrylate-paraffin embedment.
1983
The excellent butyl methacrylate-paraffin method as an embedment for light microscopy has been technically improved. More uniform and reproducible polymerization has been obtained by using a vacuum oven to degas the polymerizing mixture and to replace the air with nitrogen at 650 Torr. The amount of benzoyl peroxide required must be determined for each batch of butyl methacrylate. A teflon lined, reusable metal mold and a method of one-step blocking of tissues in preparation for sectioning are also described.