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Biomedical subjects

A M Hafez

Publications and source records attributed to A M Hafez.

11 recordsLinked to original sources
PubMed2005

Electron spin resonance and magnetic studies on some copper(II) azobarbituric and azothiobarbituric acid complexes.

Electron spin resonance and magnetic susceptibility on some copper(II) complexes prepared from phenylazobarbituric and phenylazothiobarbituric acid compounds containing 2,5-dichloro and 2,5-dimethyl groups were discussed. The thio complexes exist in dimer-monomer mixture. The corresponding copper(II) complexes of the oxygen homologous failed to exhibit association. Singlet-triplet separation values equal to -321 and -263 cm(-1) for the 2,5-dimethyl and 2,5-dichloro complexes, respectively, of the thio series. An empirical measure of the amount of tetrahedral deformation based on the values of g||/A|| assigned the square-planar geometry of the dimethyl-oxygen complex while the other complexes are with tetrahedral planar geometries. The effect of temperature on the ESR data was discussed. The diamagnetic properties of the complexes derived from 2,5-dichloro and 2,5-dimethyl thiobarbituric acid suggested the formation of Cu(I) complexes.

Copper↗
PubMed2004

Histological study of necrolytic acral erythema.

Described in 1996, necrolytic acral erythema remains the sole diagnostic cutaneous marker for hepatitis C virus infection. To date only eight cases have been described in literature, a fact that makes full histological description and appreciation of the disease process inadequate. Thirty necrolytic acral erythema cases were biopsied and detailed histological description was performed by three separate dermatopathologists who were blinded as to clinical presentation. Clinicopathological correlation was used to evaluate the disease progress. In the early stage, there is moderate regular acanthosis with variable spongiosis and inflammation, progressing to a picture resembling nummular eczema. In its fully evolved form, necrolytic acral erythema shows psoriasiform epidermal hyperplasia with marked papillomatosis. Associated findings include parakeratosis, focal hypergranulosis, subcorneal pustule, epidermal pallor, necrotic keratinocytes, which sometimes become confluent in the upper epidermis and/or track along the acrosyringia, vascular ectasia and papillary dermal inflammation. Late stage samples display some remaining acanthosis with variable inflammation. Pigment incontinence is seen in all stages.

Acrodermatitis↗
PubMed2001

Asymmetric catalysis on sequentially-linked columns.

We report a catalytic asymmetric reaction process that involves the use of solid-phase reagents and catalysts that constitute the packing of a series of "reaction columns". This process was applied to the catalytic asymmetric synthesis of beta-lactams, to yield pure products with excellent enantio- and diastereoselectivity. We have identified several advantages to conducting chemical reactions on sequential columns, including ease of catalyst and reagent recovery and simplified purification steps that preclude the need for chromatography.

Catalysis↗
PubMed2000

Column asymmetric catalysis for beta-lactam synthesis.

[structure] A catalytic asymmetric reaction process was designed involving the use of solid-phase reagents and catalysts that constitute the packing of a series of "reaction columns". This process was applied to the catalytic asymmetric synthesis of beta-lactams, yielding pure product after crystallization with exceptional enantio- and diastereoselectivity.

Anti-Bacterial Agents↗
PubMed1998

Susceptibility of Biomphalaria alexandrina to the plant Azolla pinnata and some herbicides in relation to infection with Schistosoma mansoni miracidia.

Molluscicidal activity of the herebicides 2,4-D and Graminol, as well as both extracts and dry powder of the plant Azolla pinnata were evaluated against B. alexandrina snails. It was observed that 2,4-D proved to be the most toxic compound among he tested ones, showing LC90 of 52 ppm after 24 h of exposure. Ethanol extract of Azolla showed the highest molluscicidal activity against the tested snails compared with the other extracts and dry powder (LC90 = 3300 ppm). Ethanol extract at 6600 ppm after 3 h of exposure killed 100% and 19.4% of S. mansoni miracidia and cercariae, respectively. The molluscicidal activity of 2,4-D was not influenced by the presence of Azolla (900 plants/liter) for 7 days, while Graminol effect was significantly reduced. However, the infectivity of S. mansoni miracidia to B. alexandrina snails was not affected by Azolla existence.

Animals↗
PubMed1987

Thyroid hormones, cholesterol and triglyceride levels in the camel.

Thyroxine, tri-iodothyronine, triglyceride and cholesterol were measured in the serum of clinically healthy male camels. Thyroxine and tri-iodothyronine levels, which were assayed by an immunoabsorbent method, were not correlated with either age or cholesterol levels.

Animals↗
PubMed1986

EPR study of hydrated testosterone monoclinic and orthorhombic single crystals gamma-irradiated at 295 K.

The molecular structure of free radicals formed in gamma-irradiated monoclinic and orthorhombic single crystals of hydrated testosterone were investigated by EPR spectroscopy. Two different types of radical were observed. In the monoclinic form, the radical arises by the loss of a hydrogen atom from the carbon atom C(2), whereas, in the orthorhombic form, it arises by addition of a hydrogen atom to the oxygen atom O(3). The hyperfine spectrum of the radical formed in the monoclinic single crystal originates from the interaction of the unpaired electron with one alpha-proton in position 2 and two non equivalent beta-protons in position 1. In the orthorhombic single crystal, we observed interaction of the unpaired electron, which is delocalized on the carbons C(3), C(4) and C(5) with one alpha-proton in position 4 and with four nonequivalent beta-protons connected with the carbon atoms C(2) and C(6). The hyperfine tensors of the coupling and the g-tensor of the radicals are given.

Crystallography↗