16 research outputs found
Adaptive servoventilation improves cardiac function and respiratory stability
Cheyne–Stokes respiration (CSR) in patients with chronic heart failure (CHF) is of major prognostic impact and expresses respiratory instability. Other parameters are daytime pCO2, VE/VCO2-slope during exercise, exertional oscillatory ventilation (EOV), and increased sensitivity of central CO2 receptors. Adaptive servoventilation (ASV) was introduced to specifically treat CSR in CHF. Aim of this study was to investigate ASV effects on CSR, cardiac function, and respiratory stability. A total of 105 patients with CHF (NYHA ≥ II, left ventricular ejection fraction (EF) ≤ 40%) and CSR (apnoea–hypopnoea index ≥ 15/h) met inclusion criteria. According to adherence to ASV treatment (follow-up of 6.7 ± 3.2 months) this group was divided into controls (rejection of ASV treatment or usage <50% of nights possible and/or <4 h/night; n = 59) and ASV (n = 56) adhered patients. In the ASV group, ventilator therapy was able to effectively treat CSR. In contrast to controls, NYHA class, EF, oxygen uptake, 6-min walking distance, and NT-proBNP improved significantly. Moreover, exclusively in these patients pCO2, VE/VCO2-slope during exercise, EOV, and central CO2 receptor sensitivity improved. In CHF patients with CSR, ASV might be able to improve parameters of SDB, cardiac function, and respiratory stability
Biosynthesis and Molecular Genetics of Polyketides in Marine Dinoflagellates
Marine dinoflagellates are the single most important group of algae that produce toxins, which have a global impact on human activities. The toxins are chemically diverse, and include macrolides, cyclic polyethers, spirolides and purine alkaloids. Whereas there is a multitude of studies describing the pharmacology of these toxins, there is limited or no knowledge regarding the biochemistry and molecular genetics involved in their biosynthesis. Recently, however, exciting advances have been made. Expressed sequence tag sequencing studies have revealed important insights into the transcriptomes of dinoflagellates, whereas other studies have implicated polyketide synthase genes in the biosynthesis of cyclic polyether toxins, and the molecular genetic basis for the biosynthesis of paralytic shellfish toxins has been elucidated in cyanobacteria. This review summarises the recent progress that has been made regarding the unusual genomes of dinoflagellates, the biosynthesis and molecular genetics of dinoflagellate toxins. In addition, the evolution of these metabolic pathways will be discussed, and an outlook for future research and possible applications is provided
Discovery of Nuclear-Encoded Genes for the Neurotoxin Saxitoxin in Dinoflagellates
Saxitoxin is a potent neurotoxin that occurs in aquatic environments worldwide.
Ingestion of vector species can lead to paralytic shellfish poisoning, a severe
human illness that may lead to paralysis and death. In freshwaters, the toxin is
produced by prokaryotic cyanobacteria; in marine waters, it is associated with
eukaryotic dinoflagellates. However, several studies suggest that saxitoxin is
not produced by dinoflagellates themselves, but by co-cultured bacteria. Here,
we show that genes required for saxitoxin synthesis are encoded in the nuclear
genomes of dinoflagellates. We sequenced >1.2×106 mRNA
transcripts from the two saxitoxin-producing dinoflagellate strains
Alexandrium fundyense CCMP1719 and A.
minutum CCMP113 using high-throughput sequencing technology. In
addition, we used in silico transcriptome analyses, RACE, qPCR
and conventional PCR coupled with Sanger sequencing. These approaches
successfully identified genes required for saxitoxin-synthesis in the two
transcriptomes. We focused on sxtA, the unique starting gene of
saxitoxin synthesis, and show that the dinoflagellate transcripts of
sxtA have the same domain structure as the cyanobacterial
sxtA genes. But, in contrast to the bacterial homologs, the
dinoflagellate transcripts are monocistronic, have a higher GC content, occur in
multiple copies, contain typical dinoflagellate spliced-leader sequences and
eukaryotic polyA-tails. Further, we investigated 28 saxitoxin-producing and
non-producing dinoflagellate strains from six different genera for the presence
of genomic sxtA homologs. Our results show very good agreement
between the presence of sxtA and saxitoxin-synthesis, except in
three strains of A. tamarense, for which we amplified
sxtA, but did not detect the toxin. Our work opens for
possibilities to develop molecular tools to detect saxitoxin-producing
dinoflagellates in the environment
Probleme der Herleitung von Umweltqualitaetszielen im Bereich Landschaftsaesthetik
Available from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, Duesternbrook Weg 120, D-24105 Kiel W 488 (110) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
Private versus oeffentliche Ueberwachung und Durchsetzung umweltpolitischer Instrumente
Available from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, Duesternbrook Weg 120, D-24105 Kiel W 488 (114) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
Trilevel adaptive servoventilation for the treatment of central and mixed sleep apnea in chronic heart failure patients
NOTCH4 gene polymorphisms as potential risk factors for brain arteriovenous malformation development and hemorrhagic presentation
Sleep duration and quality in heart failure patients
Sleep-disordered breathing (SDB) is highly prevalent in patients with heart failure and reduced left ventricular ejection fraction (HF-REF). SDB is classified as predominant obstructive (OSA) or central (CSA) and may alter sleep duration, sleep quality, and quality of life. This study describes sleep quality and duration in well-characterized cohorts of these patients.
Two hundred fifty consecutive patients with HF-REF (NYHA class ≥II, ejection fraction ≤45%) underwent cardiac and pulmonary examination, plus full attended in-hospital overnight polysomnography (PSG). PSG recordings were performed according to current recommendations and underwent independent, blinded analysis at a core laboratory.
Patients with HF-REF and CSA were older and had more impaired cardiac function compared to those with OSA. With respect to sleep parameters, patients with CSA spent more time in bed than those with OSA (468 ± 52 vs 454 ± 46 min, p = 0.021) while sleep efficiency was lower (67 ± 14 vs 72 ± 13% of total sleep time (TST), p = 0.008). In addition, CSA patients spent more time awake after sleep onset (101 ± 61 vs 71 ± 46 min, p = 0.001) and had more stage N1 (light) sleep (33 ± 19 vs 28 ± 16% of TST, p = 0.017). Overall, the proportion of sleep spent in N3 (slow-wave/deep) sleep in HF-REF patients with SDB was low (4.1 ± 6.3% of TST) compared with healthy adults.
HF-REF patients with CSA compared to OSA have worse sleep efficiency and quality. This could result in less restorative sleep, changes in sympathovagal balance, and impaired resetting of important reflexes, which might contribute to worse cardiovascular outcomes in HF-REF patients with SDB