[Cushing's syndrome].
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ACTH Syndrome, Ectopic↗
Biomedical subjects
A Meyer
Publications and source records attributed to A Meyer.
Feasibility of emergency surgery for the treatment of an echocardiographically detected right atrial thrombus in a patient over 80 years of age presenting with shock.
We report the case of an 83-year old woman, presenting with progressive shock, in whom a right atrial thrombus was diagnosed by cross-sectional echocardiography. Doppler echocardiography demonstrated diastolic interruption of tricuspid inflow. Emergency thrombectomy was successful and without major complications despite the advanced age.
Aged↗
Bronchoalveolar lavage (BAL) cell profiles in mild asthmatic and nonasthmatic subjects.
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Adult↗
Involvement of the endogenous lectin CSL in adhesion of Chinese hamster ovary cells.
Immunochemical localization of an endogenous mannose-binding protein, the cerebellar soluble lectin (CSL; Zanetta et al., J. Neurochem. 49, 1250-1257 (1987)), in Chinese hamster ovary cells indicated its high concentration in areas of contact between cells. This suggested its role in cell adhesion. The pattern of staining differed significantly in the cells cultured in suspension from that grown as monolayer. In cells maintained for a short time as suspension, the extracellular CSL immunoreactivity was found mainly in close apposition to the plasma membrane including contact areas. In cells cultured as monolayer, extracellularly, the lectin was found both at the cell surface and in a 75-nm thick layer between two cells, apparently adhering to the cell surface through bridges. Endogenous glycoprotein ligands of CSL were present in the cultures of CHO cells, both as membrane-bound glycoproteins and as glycoprotein ligands soluble in the presence of mannose in the absence of detergent. The lectin CSL induced adhesion between these cells as evident by low concentration of anti-CSL Fab fragments inhibiting such adhesion. These data suggested that adhesion between CHO cells occurs, in part, through a glycobiological recognition system involving CSL. This mechanism should be taken into account for the interpretation of experiments of transfection in CHO cells of the genes of glycoproteins involved in cell adhesion.
Animals↗
Monophyletic origin of Lake Victoria cichlid fishes suggested by mitochondrial DNA sequences.
Lake Victoria, together with its satellite lakes, harbours roughly 200 endemic forms of cichlid fishes that are classified as 'haplochromines' and yet the lake system is less than a million years old. This 'flock' has attracted attention because of the possibility that it evolved within the lake from one ancestral species and that biologists are thus presented with a case of explosive evolution. Within the past decade, however, morphology has increasingly emphasized the view that the flock may be polyphyletic. We sequenced up to 803 base pairs of mitochondrial DNA from 14 representative Victorian species and 23 additional African species. The flock seems to be monophyletic, and is more akin to that from Lake Malawi than to species from Lake Tanganyika; in addition, it contains less genetic variation than does the human species, and there is virtually no sharing of mitochondrial DNA types among species. These results confirm that the founding event was recent.
Africa, Eastern↗
Increased formation of DNA adducts in cultured fibroblasts of patients with aplastic anemia after in vitro incubation with benzo(a)pyrene.
In inbred mice strain DBA/2, genetically controlled differences in aryl hydrocarbon hydroxylase (AHH) activity have been demonstrated that predispose to aplastic anemia. To test the hypothesis of a similar mechanism in humans, we studied the formation of benzo(a)pyrene DNA adducts and water-soluble metabolites in skin fibroblasts from eight patients with aplastic anemia and eight normal controls. The ratio of water-soluble metabolites and DNA adducts was 46.5 +/- 16.6 in patients and was significantly lower as compared to 82.9 +/- 38.5 in controls (P less than 0.05). We conclude that increased formation of genotoxic intermediates may be a pathogenetic mechanism in some patients with aplastic anemia.
Adult↗
Origin of tetrapods inferred from their mitochondrial DNA affiliation to lungfish.
This paper shows that questions of an unexpected phylogenetic depth can be addressed by the study of mitochondrial DNA (mtDNA) sequences. For decades, it has been unclear whether coelacanth fishes or lungfishes are the closest living relatives of land vertebrates (Tetrapoda). Segments of mtDNA from a lungfish, the coelacanth, and a ray-finned fish were sequenced and compared to the published sequence of a frog mtDNA. A tree based on inferred amino acid replacements, silent transversions, and ribosomal RNA (rRNA) substitutions showed with statistical confidence that the lungfish mtDNA is more closely related to that of the frog than is the mtDNA of the coelacanth. This result appears to rule out the possibility that the coelacanth lineage gave rise to land vertebrates; hence, morphological characters that link the latter two groups are possibly due to convergent evolution or reversals and not to common descent. Besides supporting the theory that land vertebrates arose from an offshoot of the lineage leading to lungfishes, the molecular tree facilitates an evolutionary interpretation of the morphological differences among the living forms. It would appear that the common ancestor of lungfishes and tetrapods already possessed multiple morphological traits preadapting their locomotion, circulation, and respiration for life on land.
Animals↗
Organic chemistry of C60 (Buckminsterfullerene): chromatography and osmylation.
Treatment of C60 with osmium tetroxide and pyridine gives the osmate ester (2:1 adduct) establishing that oxygen functionality can be added to C60 without disrupting the carbon framework.
Carbon↗
Large sequence divergence among mitochondrial DNA genotypes within populations of eastern African black-backed jackals.
In discussions about the relative rate of molecular evolution, intraspecific variability in rate is rarely considered. An underlying assumption is that intraspecific sequence differences are small, and thus variations in rate would be difficult to detect or would not affect comparisons among distantly related taxa. However, several studies on mammalian mitochondrial DNA (mtDNA) have revealed considerable intraspecific sequence divergence. In this report, we test for differences in the rate of intraspecific evolution by comparing mtDNA sequences, as inferred from restriction site polymorphisms and direct sequencing, between mtDNA genotypes of the eastern African black-backed jackal, Canis mesomelas elongae, and those of two other sympatric jackal species. Our results are unusual for several reasons. First, mtDNA sequence divergence within several contiguous black-backed jackal populations is large (8.0%). Previous intraspecific studies of terrestrial mammals have generally found values of less than 5% within a single population, with larger divergence values most often occurring among mtDNA genotypes from geographically distant or isolated localities. Second, only 4 mtDNA genotypes were present in our sample of 64 jackals. The large sequence divergence observed among these mtDNA genotypes suggests there should be many more genotypes of intermediate sequence divergence if they had evolved in sympatry. Finally, estimates of the rate of mtDNA sequence evolution differ by approximately 2- to 4-fold among black-backed jackal mtDNA genotypes, thus indicating a substantial heterogeneity in the rate of sequence evolution. The results are difficult to reconcile with ideas of a constant molecular clock based on random fixation of selectively neutral or nearly neutral mtDNA sequence mutations.
Africa, Eastern↗
Significant difference and discrimination.
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Data Interpretation, Statistical↗
[Influence of epidural anesthesia on the progression of labor in primiparas].
A comparative study was carried out on 363 primiparas at the University Hospital of Montpellier to assess what influence epidural anaesthesia had on the number of instrumental deliveries that had to be carried out in our service and in the way it is conducted. This study shows that the increase in the number of instrumental deliveries found in women who deliver under epidural anaesthesia was mainly due to the abnormal obstetric conditions for which the epidural anaesthetic was anyhow given. There was only a small increase in the numbers that had to be delivered instrumentally in those women had epidural anaesthesia "for comfort". This was not particularly significant with anterior presentations.
Anesthesia, Epidural↗
[Therapy of HIV associated mild and moderately severe Pneumocystis carinii pneumonia with 600 mg/die pentamidine aerosol. Results of a multicenter study].
In 22 HIV positive patients a mild to moderate pneumocystis carinii pneumonia was treated by daily inhalation for 21 days of 600 mg pentamidine, divided into two inhalation phases with the inhalation of 300 mg pentamidin each. In 13 patients (59%) treatment was successful. In five cases, therapy was stopped in the first treatment week because of lacking clinical effectiveness resp. clinical deterioration. In four cases, therapy was discontinued in the further course. The subsequent treatment was successful in all cases. In the case of otherwise good tolerance, in two cases there was a hypoglycemia, in one case with clinical signs. In no case there was any sign of an extrapulmonary pneumocystosis.
Administration, Inhalation↗
Treatment of herniated lumbar disc by percutaneous nucleotomy with aspiration. Preliminary results in 70 cases.
Seventy patients suffering from lumbar pain with sciatica, radiculalgia or lumbodynia were reviewed at least 3 months after automated percutaneous nucleotomy (Nucleotome). There were 26 women and 44 men, aged from 19 to 72 years. Results were highly satisfactory in 39 patients (56.5%). Among these, 10 had lumbar pain of discal origin, 15 had pure radiculalgia and 14 had lumbar pain and radiculalgia. Incomplete improvement requiring medical treatment was obtained in 11 patients (15.5%). The procedure was unsuccessful in 20 patients (28.5%) with persistence or worsening of the initial symptoms; 5 of them subsequently underwent chemonucleolysis with 4 good medium-term results and 1 failure. These preliminary results show that percutaneous nucleotomy seems to be effective in lumbar pain of discal origin, with a 66.5% success rate. In patients with pure radiculalgia or lumbar pain cum radiculalgia the results are less impressive, with a success rate of about 50%. However, this well-tolerated technique may be used as first-line treatment of herniated discs when the discs are small, subligamentous and non migrated.
Adult↗
[High-dose inhaled beta-2 sympathomimetics in severe bronchial asthma].
We made the observations that in patients with severe bronchial asthma, the inhalative dose of beta-2 sympathomimetics that was required for optimal bronchial dilation revealed a large inter-individual scatter. In 21 patients, the inhalation of a maximum of 10 metered doses of salbutamol at intervals of five minutes each, led to a mean (SD) increase in the FEV 1.0 from 1.3 (0.6) 1 to 1.8 (0.7) 1. The maximum increase in the FEV 1.0 was achieved in 10 patients following the inhalation of 1 to 3 metered doses, and in 11 patients after 4 to 10 such doses. The individual requirement for inhaleable beta-2 agonists should therefore be taken into account when planning treatment.
Administration, Inhalation↗
Ribbon synapses of the mammalian retina contain two types of synaptic bodies--ribbons and spheres.
The present paper reports that the synaptic bodies of the retinal ribbon synapses in rat, guinea pig, golden hamster and mouse are a heterogeneous population of organelles. In addition to the well-known synaptic ribbons sensu stricto which consist of a platelike electron-dense central structure surrounded by electron-lucent synaptic vesicles, there are what is termed synaptic spheres, in which the core is not platelike, but round to oval. In rat retinae procured at day, ribbons outnumbered spheres by a factor of 4. At night spheres were not seen in photoreceptor cells. Spheres, like ribbons, may lie some distance from the synaptic site, perhaps indicating transit from their site of origin to the synapse. At night ribbons are longer than at daytime. In addition to the previously described connecting stalks between synaptic vesicles and the electron-dense ribbons, the presence of filamentous stalks between adjacent synaptic vesicles is described. The latter stalks, depending on their presence or absence, may influence the position of the synaptic vesicles in relation to the synaptic body and/or the presynaptic membrane. It is concluded that the plasticity of retinal synapses cannot be fully appreciated unless the temporal changes of ribbons, spheres and the connecting stalks are taken into consideration.
Animals↗
Dynamics of mitochondrial DNA evolution in animals: amplification and sequencing with conserved primers.
With a standard set of primers directed toward conserved regions, we have used the polymerase chain reaction to amplify homologous segments of mtDNA from more than 100 animal species, including mammals, birds, amphibians, fishes, and some invertebrates. Amplification and direct sequencing were possible using unpurified mtDNA from nanogram samples of fresh specimens and microgram amounts of tissues preserved for months in alcohol or decades in the dry state. The bird and fish sequences evolve with the same strong bias toward transitions that holds for mammals. However, because the light strand of birds is deficient in thymine, thymine to cytosine transitions are less common than in other taxa. Amino acid replacement in a segment of the cytochrome b gene is faster in mammals and birds than in fishes and the pattern of replacements fits the structural hypothesis for cytochrome b. The unexpectedly wide taxonomic utility of these primers offers opportunities for phylogenetic and population research.
Amino Acid Sequence↗
Comparative studies of in vitro transformation by ethylene oxide and gamma-radiation of C3H/10T1/2 cells.
A dose-dependent transforming ability of the direct-acting alkylating agent, ethylene oxide (EtO), was demonstrated in C3H/10T1/2 mouse embryo fibroblasts. Morphologically transformed colonies were observed 5-6 weeks after the treatment with EtO. The transforming effectiveness of EtO was compared with that of gamma-radiation, and the rad-equivalence of EtO was calculated to be approximately 90 rad/mMh. This value is consistent with earlier estimates based on induced mutation in various biological systems and thus indicates the applicability of the C3H/10T1/2 cell system in the risk estimation of human exposure to genotoxic compounds.
Animals↗
Modulation of aortic smooth muscle cell membrane potential by extracellular calcium.
Removal of extracellular calcium may result in depolarization of the resting cell membrane potential. This has been attributed to the stabilizing action of calcium on the ionic permeability of the cell membrane. It is unknown whether this phenomenon is exclusively mediated by extracellular calcium or through associated changes in intracellular calcium. To examine this, we exposed rat aortic smooth muscle cells in culture to different calcium concentrations and studied their effects on the resting membrane potential and intracellular calcium activity. The resting membrane potential was dependent on the extracellular potassium concentration. Exposure to reduced extracellular calcium concentrations (0.25 and 0.5 mM) caused a steep and reversible depolarization of the membrane potential, but intracellular calcium, measured with fura 2-AM, was not reduced below that measured in control conditions (1.8 mM). Atomic absorption spectrophotometric measurements did not indicate a measurable gain in cell sodium after reduction of extracellular calcium levels. We conclude that extracellular calcium controls the resting cell membrane potential of vascular smooth muscle through a mechanism that is independent of cytosolic Ca2+ activity.
Action Potentials↗