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Biomedical subjects

G Rees

Publications and source records attributed to G Rees.

14 recordsLinked to original sources

Solitary keratoacanthoma of the nasal vestibule.

Keratoacanthomas are lesions which rarely present to Otorhinolaryngologists; however they must be considered in the differential diagnosis of any rapidly growing lesion in the head and neck. We report a case of a keratoacanthoma of the nasal vestibule which caused clinical and histopathological difficulties in diagnosis. Keratoacanthomas and the treatment options are discussed.

Adult

Voltammetric behaviour of salicylic acid at a glassy carbon electrode and its determination in serum using liquid chromatography with amperometric detection.

Cyclic voltammetry was used to investigate the oxidation of salicylic acid at a planar glassy carbon electrode. The electrode reaction was found to be dependent on the pH and ionic strength of the acetate buffer, which contained 35% methanol. Under these conditions the maximum electrochemical signal was obtained with a supporting electrolyte of 0.06 mol dm-3 acetate buffer in 35% methanol (pH 5.0). The peak current value (ip) increased by approximately 10% when the methanol concentration was decreased to 8%. The substance was found to undergo an irreversible reaction involving one electron and possibly two protons in the initial oxidation step with at least one possible quasi-reversible follow-up reaction. The optimum mobile phase for the liquid chromatography, with amperometric detection, of the serum extracts was found to be 0.06 mol dm-3 acetate buffer in 8% methanol (pH 5.0); the acidified serum was extracted with a mixture of chloroform and acetonitrile (60 + 40), prior to injection onto a reversed-phase column. The peak current was measured at +1.35 V and the calibration graph was found to be linear in the range 4-200 ng of sample injected. The average recovery from serum was found to be 60% with a relative standard deviation of 5.8%. A pharmacokinetic study was carried out and the results obtained were comparable to those found in the literature. It was concluded that the method developed had possible application for the measurement of trace levels of salicylic acid in clinical studies.

Chromatography, High Pressure Liquid

Isolation of mouse CD44 cDNA: structural features are distinct from the primate cDNA.

CD44 is a glycoprotein that participates in adhesion of lymphocytes to high endothelial cells of lymph organs and likely functions in other intercellular adhesions as well. We have isolated a mouse CD44 cDNA by polymerase chain reaction amplification of cDNA synthesized from total cellular RNA isolated from 38C-13, a B-lymphocyte cell line. The oligonucleotide sequences were based at the 5' end on the baboon CD44 sequence upstream of and including the translation initiator ATG and at the 3' end on a mouse CD44 sequence that was determined from a rare, incomplete cDNA clone. The mouse CD44 DNA sequence is similar to the baboon CD44 sequence but has structural features that are distinct. The external domain has a region that is only 35% similar between the mouse and primate proteins, in contrast to 85%-90% similarity in the rest of the sequence. In addition, just upstream from the predicted cleavage site of the leader peptide, nucleotide insertions result in the addition of two or four amino acids, depending upon the mouse strain. An amino acid replacement between two strains carrying different CD44 (also called Pgp-1) allotypes is likely responsible for the Pgp-1 polymorphism. The most striking aspect of mouse CD44 is that the RNA does not fractionate with polyadenylylated RNA, unlike the CD44 RNA in human, baboon, rat, and chicken.

Amino Acid Sequence

Obstetric anaesthetic and analgesic services in Wales.

A survey of obstetric anaesthetic services in Wales covering 21 major units in which over 31 000 deliveries take place annually showed inadequacies in staffing at consultant and resident anaesthetist level. At least 20 additional consultant sessions were required to meet the recommendations of the Association of Anaesthetists of Great Britain and Ireland. If patients' requests for epidural analgesia are to be met some reorganisation and centralisation of facilities is needed.

Anesthesia, Epidural