PubMed Health⌕ Search

Biomedical subjects

A Mikou

Publications and source records attributed to A Mikou.

At least 19 recordsLinked to original sources
PubMed2006

[Biphasic sarcomatoid carcinoma of the thyroid: an exceptional localization of a rare tumor].

Thyroid sarcomatoid carcinoma is a rare and aggressive neoplasm composed of a follicular carcinoma which is contiguous or admixed with a pleomorphic spindle cell component. We report the case of a thyroid tumor reputed to have a poor outcome, in a 62-year-old woman. The radical thyroidectomy specimen was totally invaded. Results of immunoperoxidase staining for thyroglobulin and epithelial markers were positive in the areas of follicular carcinoma and negative in the sarcomatous component. The patient died a few days later due to septic shock. The epithelial and mesenchymal components of thyroid carcinosarcoma were both part of the neoplastic parenchyma and evolved from a single common stem cell, in agreement with the hypothesis that the tumors are of monoclonal origin. The definition of this tumor as its histogenesis and prognostic are discussed.

Carcinoma↗
PubMed1994

The three-dimensional NMR solution structure of alpha-cobratoxin at pH 7.5 and conformational differences with the NMR solution structure at pH 3.2.

The 3D solution structure of alpha-cobratoxin, a neurotoxin purified from the Naja naja siamensis snake venom, has been determined by Nuclear Magnetic Resonance spectroscopy, in conjunction with distance geometry and restrained molecular dynamics, at pH 7.5. A total of 490 distance restraints were obtained from NOE intensities and 25 phi dihedral angle restraints deduced from J-coupling data. The generated structures are well defined with root mean square deviations from a geometrical mean structure of 0.107 +/- 0.036 nm for the backbone atoms and 0.128 +/- 0.073 nm for the side-chain atoms (considering residues 1 to 66 minus 26 to 35). A comparison between the generated structures at pH 7.5 and the mean NMR solution structure at pH 3.2 revealed that the 3D structure of alpha-cobratoxin is more compact at neutral pH. This major difference is mainly due to the pH-dependent conformational variations of three residues His18, Thr44 and Thr59.

Amino Acid Sequence↗
PubMed1993

Muslims with non-insulin dependent diabetes fasting during Ramadan: treatment with glibenclamide.

OBJECTIVE: To compare the efficacy of two glibenclamide regimens in patients with non-insulin dependent diabetes who were fasting during Ramadan and regular glibenclamide treatment in the non-fasting group. DESIGN: Non-randomised control group of patients who did not fast during Ramadan and two groups of patients who fasted randomised equally to one of two regimens: to take their usual morning dose of glibenclamide in the evening and their usual evening dose before dawn; or to follow this pattern but to reduce the total dose by a quarter. SETTING: Two university hospitals, one private hospital, and two private clinics in Casablanca and Rabat, Morocco. SUBJECTS: 591 diabetic patients (198 men, 391 women, two unspecified) with similar duration of diabetes and length and amount of glibenclamide treatment, of whom 542 completed the study. MAIN OUTCOME MEASURES: Serum fructosamine and total glycated haemoglobin concentrations and number of hypoglycaemic events. RESULTS: At the end of Ramadan there were no significant differences between the groups in fructosamine concentration (400 mumol/l in controls and 381 mumol/l and 376 mumol/l in the fasting groups); percentage of glycated haemoglobin (14.7%, 14.0%, and 13.6%); or number of hypoglycaemic events during Ramadan (11, 14, and 10). CONCLUSION: Glibenclamide is effective and safe for patients with non-insulin dependent diabetes who fast during Ramadan. The easiest regimen is to take the normal morning dose (together with any midday dose) at sunset and any evening dose before dawn.

Diabetes Mellitus, Type 2↗
PubMed1992

Alpha-cobratoxin: proton NMR assignments and solution structure.

The solution structure of alpha-cobratoxin, a neurotoxin purified from the venom of the snake Naja naja siamensis, at pH 3.2 is reported. Sequence-specific assignments of the NMR resonances was attained by a combination of a generalized main-chain-directed strategy and of the sequential method. The NMR data show the presence of a triple-stranded beta-sheet (residues 19-25, 36-41, and 52-57), a short helix, and turns. An extensive number of NOE cross peaks were identified in the NOESY NMR maps. These were applied as distance constraints in a molecular modeling protocol which includes distance geometry and dynamical simulated annealing calculations. A single family of structures is observed which fold in such a way that three major loops emerge from a globular head. The solution and crystal structures of alpha-cobratoxin are very similar. This is in clear contrast to results reported for alpha-bungarotoxin where significant differences exist.

Amino Acid Sequence↗
PubMed1992

Toxin III of the scorpion Androctonus australis Hector: proton nuclear magnetic resonance assignments and secondary structure.

1H NMR has been applied to a 3.5 mM, pH 5.4, solution of toxin III (64 amino acids) from venom of the scorpion Androctonus australis Hector. The resonance assignment strategy began by applying a generalized main-chain directed method for rapid identification and resonance assignments of secondary structures. The remaining resonances were assigned by the sequential method. Major structural features include a helix of 2 1/2 turns (residues 20-28) which is linked by two disulfide bridges to the central strand of a triple-stranded anti-parallel beta-sheet. Turns were identified at residues 15-17, 47-49 and also at residues 51-53. Numerous NOEs have been observed between hydrophobic residues which suggest the presence of a hydrophobic core; these include Leu37, Leu23, Val47, Tyr14, Trp45 and Tyr5. The Trp45 and Tyr5 rings lie orthogonal to one another. No crystal structure has been solved for this AaH III toxin. Comparisons are made with other members of the scorpion toxin family.

Amino Acid Sequence↗
PubMed1990

Rapid determination and NMR assignments of antiparallel sheets and helices of a scorpion and a cobra toxin.

An NMR method is described which should provide a rapid means for determining and assigning antiparallel sheets and helices in small proteins. It begins by locating apparent NOESY crosspeaks which suggest the presence of the secondary structure; this is followed by searches for MCD patterns (Englander & Wand (1987) Biochemistry 22, 5953) which are characteristic of these structures. As a result, only spin-systems of the amino acids within the secondary structure need to be defined. A triple-stranded, antiparallel sheet and a helix have been found and assigned for both alpha-cobratoxin and the scorpion toxin AaH III.

Animals↗