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Biomedical subjects

P Messner

Publications and source records attributed to P Messner.

At least 91 records · Page 5Linked to original sources

[Extracardiac malformations in tetralogy of Fallot].

The purpose of our study was to determine the incidence and type of malformations associated with tetralogy of Fallot (TF). Among 133 patients followed up for 12 years, 30 who had either complete TF (n = 26) or pulmonary atresia and interventricular septal defect (n = 4) presented with another, extracardiac malformation. These malformations were part of a malformative syndrome in 21/30 patients, including 4 trisomies 21, 6 embryofoetopathies unquestionably (antiepileptics n = 2, alcohol n = 1) or possibly (hormonal treatment n = 1) of environmental origin, 6 branchial arch pathologies and 5 miscellaneous syndromes. The extracardiac malformation was isolated in the remaining 9 patients, including 5 cases of skeletal anomaly and one case each of omphalocele and microcephaly. Altogether, in these 30 patients skeletal and neurosensory anomalies were largely predominant. Skeletal anomalies involved the vertebral column in 8 cases (cervical 3, thoracic 4, lumbar 1) and the limbs in 5 cases (2 of which were phocomelias). The 4 patients with pulmonary atresia and interventricular septal defect also presented with an early embryopathy: Shprinzen's velocardiofacial syndrome (n = 2), DiGeorge syndrome (n = 1) and situs inversus (n = 1). We compared TF with other congenital heart diseases in our population and found that the incidence of associated malformations was about average. The various associations are discussed. In genetic syndromes, trisomy 21 predominates and TF is less frequent than atrioventricular canal. In syndromes of environmental origin, the role of antiepileptic drugs (chiefly phenytoin and trimethadione) is well-known, alcohol is less often responsible and the TF-phocomelia association is suggestive of progesterone. In branchial arch syndromes, TF is the usual cardiopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities, Drug-Induced↗

Changes in vertebral end plates in congenital spine deformities.

The authors investigated morphologically material from 30 patients with congenital spine deformities operated on at the 2nd Orthopaedic University Department in Brno, and the spines of two patients who underwent a spinal operation and later died from other causes, and also the spines of young, healthy road accident victims. In the course of operations for congenital deformities of the spine representative tissue samples were taken (hemivertebrae, quarter vertebrae, etc.), along with the adjacent parts of intervertebral disks. The authors concentrated mainly on the growth defects of deformed vertebrae and microscopic changes in the adjacent cartilage plates. In this way light was thrown on some questions of both defects of formation and defects of segmentation of the mesenchymal base of the spine. The defects of ossification and growth disorders observed are, in the authors' opinion, an important component in the occurrence of congenital deformities and idiopathic scolioses and have a major effect on their progression.

Female↗

A randomized hemodynamic comparison of intravenous amiodarone with and without Tween 80.

In 20 patients undergoing coronary arteriography, the hemodynamic effects of an experimental preparation of i.v. amiodarone 5 mg kg-1 without Tween 80 (N) (10 patients) were compared with those of the commercial form with Tween 80 (A) (10 patients). Analysis of variance demonstrated differences during the 3 min of injection and for 3 min afterwards: left ventricular systolic pressure decreased from 110 + 11 to 86 +/- 11 mmHg (P = 0.001) after A and from 114 +/- 22 to 106 +/- 19 (P = 0.05) after N (comparison P = 0.01) while related tachycardia was also more pronounced after A (comparison P = 0.001). Left ventricular end diastolic pressure transiently decreased after A while continuously increasing after N (P = 0.05). During the following 30 min both A and N caused similar bradycardia, increase in ventricular filling pressure, vascular resistance and decrease in cardiac and contractility indexes. Amiodarone blood levels were similar after A or N. These data document a significant initial short duration vasoplegia, mainly related to Tween 80, after A, when amiodarone itself after producing a similar very slight effect causes bradycardia, and a moderate and progressive negative inotropic effect. It was concluded that while the experimental form would be of interest, the risk of severe hypotension after i.v. Cordarone can be largely avoided by using a slower rate of infusion, especially in patients with hypovolemic status.

Adult↗

Destruction of ethidium bromide in solution by ozonolysis.

Ethidium bromide can be rapidly destroyed in aqueous solutions or in isoamyl alcohol by ozonolysis in the presence of H2O2 to give a mixture of organic acids. In a variety of buffers commonly used in recombinant DNA technology destruction of ethidium bromide was more than 99.9%. The yellow reaction mixture after ozonolysis was shown to be nonmutagenic. This method may be used in laboratories for the disposal of ethidium bromide wastes.

Chemical Phenomena↗

Isolation and structure determination of a diacetamidodideoxyuronic acid-containing glycan chain from the S-layer glycoprotein of Bacillus stearothermophilus NRS 2004/3a.

A glycan isolated from the surface-layer glycoprotein of Bacillus stearothermophilus strain NRS 2004/3a was shown by 1H- and 13C-n.m.r. spectroscopy to have the tetrasaccharide repeating-unit ----4)-beta-ManpA2,3(NAc)2-(1----3)-alpha-GlcpNAc-(1----4)-beta- ManpA2,3(NAc)-(1----6)-alpha-Glcp(1----.

Carbohydrate Conformation↗

Structural and chemical characterization of S-layers of selected strains of Bacillus stearothermophilus and Desulfotomaculum nigrificans.

The structures, amino acid- and neutral sugar compositions of the crystalline surface layers (S-layers) of four selected strains each of Bacillus stearothermophilus and Desulfotomaculum nigrificans were compared. Among the four strains of each species a remarkable diversity in the molecular weights of the S-layer subunits and in the geometry and constants of the S-layer lattices was apparent. The crystalline arrays included hexagonal (p6), square (p4) and oblique (p2) lattices. In vitro self-assembly of isolated S-layer subunits (or S-layer fragments) led to the formation of flat sheets or open-ended cylindrical assembly products. The amino acid composition of the S-layers exhibited great similarities and was predominantly acidic. With the exception of the S-layers of two strains of B. stearothermophilus (where only traces of neutral sugars could be detected), all other S-layer proteins seemed to be glycosylated. Among these strains significant differences in the amount and composition of the glycan portions were found. Based on this diversity interesting questions may be asked about the biological significance of the carbohydrate units of glycoproteins in prokaryotic organisms.

Amino Acids↗

Ultrastructure of the cell envelope of the archaebacteria Thermoproteus tenax and Thermoproteus neutrophilus.

The ultrastructures of the regular surface layers (S-layers) of the extremely thermophilic archaebacteria Thermoproteus tenax and Thermoproteus neutrophilus were examined by freeze-etching, freeze-drying, and negative staining methods combined with optical and digital image enhancement. In both strains, a monolayer of macromolecules arranged in hexagonal arrays with center-to-center spacings of approximately 30 nm was the only component of the cell wall. The gross morphologies of the S-layer lattices of the two organisms were similar and showed the same handedness in the arrangement of the protomers of the morphological units. Striking differences were found in the anionic charge distributions on the surfaces of the two S-layer proteins as determined by labeling with polycationic ferritin. Analysis of the lattice orientation, together with the number and distribution of lattice faults on intact cells, provided a strong indication that the S-layers of both organisms have a shape-determining function.

Archaea↗