Platypnea-orthodeoxia associated with a fenestrated atrial septal aneurysm: Case Report

Background

Stress echocardiography is a cost-effective tool for the modern noninvasive diagnosis of coronary artery disease. Several physical and pharmacological stresses are used in combination with echocardiographic imaging, usually exercise, dobutamine and dipyridamole. The safety of a stress is (or should be) a major determinant in the choice of testing. Although large scale single center experiences and multicenter trial information are available for both dobutamine and dipyridamole stress echo testing, complications or side effects still can occur even in the most experienced laboratories with the most skilled operators.

Case presentation

We decided to present a case collection of severe complications during pharmacological stress echo testing, including a ventricular tachycardia, cardiogenic shock, transient ischemic attack, torsade de pointe, fatal ventricular fibrillation, and free wall rupture.

Conclusion

We believe that, in this field, every past complication described is a future complication avoided; what happens in your lab is more true of what you read in journals; and Good Clinical Practice is not "not having complications", but to describe the complications you had.     

Thermal dependence of serotonergic modulation of neural activity in the hamster

1. The modulatory effect of serotonin on CA1 pyramidal cells in the hamster (Mesocricetus auratus) hippocampus was examined over a range of temperatures. 2. Following repetitive Schaffer collateral/commissural stimulation, changes in the amplitude of population spikes (the synchronous firing of CA1 pyramidal cells) were recorded in the hamster, a hibernator. Amplitudes were measured after 10 microM serotonin was added to and then withdrawn from the perfusing medium with the temperature of the bath fixed at different temperatures. 3. Between 35 degrees C and 15 degrees C a depression in population spike amplitude of at least 10% was seen in 36 of 43 trials, with an average depression of 68%. No significant temperature dependence of the depressive effect was seen. 4. Following the removal of serotonin from the perfusate, the spike amplitude was enhanced over the same range of temperatures, averaging 33% higher than control values. The enhancement was most pronounced at 35 degrees C and 15 degrees C and smallest at 25 degrees C. 5. Thus, over the entire temperature range of 35 degrees C to 15 degrees C, serotonin exerted a dual modulatory effect on the spike amplitude, a depression followed by an enhancement. Serotonin's modulatory effects on pyramidal cell excitation persist over temperatures encountered as the hamster enters hibernation.     

Characterization of 13 newly isolated strains of anaerobic, cellulolytic, thermophilic bacteria

Characteristics of 13 newly isolated thermophilic, anaerobic, and cellulolytic strains were compared with previously described strains of Clostridium thermocellum: ATCC 27405 and JW20 (ATCC 31549). Colony morphology, antibiotic sensitivity, fermentation end-products, and cellulose degradation were documented. All 13 strains were sensitive to erythromycin (5 μg/ml) and chloramphenicol (25 μg/ml), and all strains but one were sensitive to kanamycin (20 μg/ml). Polymerase chain reaction (PCR) amplification using primers based on gene sequences from C. thermocellum ATCC 27405 was successful for all 13 strains in the case of the hydrogenase gene and 11 strains in the case of phosphotransacetylase/acetate kinase genes. Ten strains amplified a product of the expected size with primers developed to be specific for C. thermocellum 16SrRNA primers. Two of the 13 strains did not amplify any product with the PCR primers designed for the phosphotransacetylase/acetate kinase and 16SrRNA primers. A MboI-like GATC- recognizing restriction activity was present in all of the five strains examined. The results of this study have several positive implications with respect to future development of a transformation system for cellulolytic thermophiles. Journal of Industrial Microbiology & Biotechnology (2001) 27, 275–280. Received 12 September 2000/ Accepted in revised form 20 November 2000     

Cytosolic isocitrate dehydrogenase in humans, mice, and voles and phylogenetic analysis of the enzyme family

In this study, we report cDNA sequences of the cytosolic NADP-dependent isocitrate dehydrogenase for humans, mice, and two species of voles (Microtus mexicanus and Microtus ochrogaster). Inferred amino acid sequences from these taxa display a high level of amino acid sequence conservation, comparable to that of myosin beta heavy chain, and share known structural features. A Caenorhabditis elegans enzyme that was previously identified as a protein similar to isocitrate dehydrogenase is most likely the NADP-dependent cytosolic isocitrate dehydrogenase enzyme equivalent, based on amino acid similarity to mammalian enzymes and phylogenetic analysis. We also suggest that NADP-dependent isocitrate dehydrogenases characterized from alfalfa, soybean, and eucalyptus are most likely cytosolic enzymes. The phylogenetic tree of various isocitrate dehydrogenases from eukaryotic sources revealed that independent gene duplications may have given rise to the cytosolic and mitochondrial forms of NADP-dependent isocitrate dehydrogenase in animals and fungi. There appears to be no statistical support for a hypothesis that the mitochondrial and cytosolic forms of the enzyme are orthologous in these groups. A possible scenario of the evolution of NADP-dependent isocitrate dehydrogenases is proposed.      

Phytoplankton uptake of ammonium and urea during growth on oxidized forms of nitrogen

Uptake capabilities for ammonium (NH₄⁺) and urea by diatoms(Thalassiosira pseudonana and Skeletonema costatum) growingon oxidized forms of nitrogen were studied in short-term uptakeexperiments. Even when nutrient-saturated, an enhanced uptakecapability not coupled with the growth rate was present forNH₄⁺ and urea. No such enhanced uptake ability was seen forNO₂^– or NO₃^– under either nutrient-saturated ornutrient-depleted conditions. The presence of NH₄⁺ decreasedthe enhanced ability to take up urea, but the urea uptake ratein 5 min incubations remained greater than the growth rate evenwhen NH₄⁺ was present.     

Loss of meiosis in Aspergillus

If strictly mitotic asexual fungi lack recombination, the conventional view predicts that they are recent derivatives from older meiotic lineages. We tested this by inferring phylogenetic relationships among closely related meiotic and strictly mitotic taxa with Aspergillus conidial (mitotic) states. Phylogenies were constructed by using DNA sequences from the mitochondrial small ribosomal subunit, the nuclear ribosomal internal transcribed spacers, and the nuclear 5.8S ribosomal gene. Over 920 bp of sequence was analyzed for each taxon. Phylogenetic analysis of both the mitochondrial and nuclear data sets showed at least four clades that possess both meiotic and strictly mitotic taxa. These results support the hypothesis that strictly mitotic lineages arise frequently from more ancient meiotic lineages with Aspergillus conidial states. Many of the strictly mitotic species examined retained characters that may be vestiges of a meiotic state, including the production of sclerotia, sclerotium-like structures, and hulle cells.      

The phylogenetic status of arthropods, as inferred from 18S rRNA sequences

Partial 18S rRNA sequences of five chelicerate arthropods plus a crustacean, myriapod, insect, chordate, echinoderm, annelid, and platyhelminth were compared. The sequence data were used to infer phylogeny by using a maximum-parsimony method, an evolutionary-distance method, and the evolutionary-parsimony method. The phylogenetic inferences generated by maximum-parsimony and distance methods support both monophyly of the Arthropoda and monophyly of the Chelicerata within the Arthropoda. These results are congruent with phylogenies based on rigorous cladistic analyses of morphological characters. Results support the inclusion of the Arthropoda within a spiralian or protostome coelomate clade that is the sister group of a deuterostome clade, refuting the hypothesis that the arthropods represent the "primitive" sister group of a protostome coelomate clade. Bootstrap analyses and consideration of all trees within 1% of the length of the most parsimonious tree suggest that relationships between the nonchelicerate arthropods and relationships within the chelicerate clade cannot be reliably inferred with the partial 18S rRNA sequence data. With the evolutionary-parsimony method, support for monophyly of the Arthropoda is found in the majority of the combinations analyzed if the coelomates are used as "outgroups." Monophyly of the Chelicerata is supported in most combinations assessed. Our analyses also indicate that the evolutionary-parsimony method, like distance and parsimony, may be biased by taxa with long branches. We suggest that a previous study's inference of the Arthropoda as paraphyletic may be the result of (a) having two few arthropod taxa available for analysis and (b) including long-branched taxa.