A comprehensive scoping review on transvenous temporary pacing therapy

Netherlands Heart Journal - Transvenous temporary cardiac pacing therapy (TV-TP) is widely used to treat life-threatening arrhythmias. Yet aggregated evidence on TV-TP is limited. We conducted...     

Evolutionary relationships and reproductive isolating mechanisms in the rice frog (Fejervarya limnocharis) species complex from Sri Lanka, Thailand, Taiwan and Japan, inferred from mtDNA gene sequences, allozymes, and crossing experiments

The rice frog (Fejervarya limnocharis) species complex is widely distributed, from India to Japan, and most prevalently in Southeast Asia. Conspicuous morphological variation has been reported for this species complex throughout its distribution range. In the present study, we used mtDNA gene sequence and allozyme analyses to infer evolutionary affinities within this species complex using eight populations (Sri Lanka; Bangkok and Ranong in Thailand; Taiwan; and Hiroshima, Okinawa, Ishigaki and Iriomote in Japan). We also conducted crossing experiments among four populations from Japan, Thailand, and Sri Lanka in order to find out more about the reproductive isolating mechanisms that might exist among the East, Southeast, and South Asian populations of this species complex. The crossing experiments revealed that the Sri Lanka population is reproductively isolated from the Hiroshima, Bangkok, and Ranong populations by complete hybrid inviability, and that the Bangkok population may be reproductively isolated from the Hiroshima population by partial hybrid inviability. Thus, it is not unreasonable to regard the Sri Lanka population as a species separated from F. limnocharis. The mtDNA and allozyme data showed that the Ranong population is most closely related to the Bangkok population in nuclear genome, but more similar to the Okinawa and Taiwan populations in mtDNA genome. The present, preliminary survey may raise questions about the species status of these particular populations and also about the nature of the biological species concept.     

Evaluation of two- and three-dimensional streptavidin binding platforms for surface plasmon resonance spectroscopy studies of DNA hybridization and protein-DNA binding

Surface plasmon resonance (SPR) spectroscopy has been used to study DNA assembly, DNA hybridization, and protein-DNA interactions on two streptavidin (SA) sensor chips. On one chip, SA molecules are immobilized on a biotin-exposed surface, forming an ordered two-dimensional (2D) SA monolayer. The other chip, BIAcore's SA chip, contains SA molecules immobilized within a three-dimensional (3D) carboxylated dextran matrix. Compared to the 2D chip, the 3D SA matrix allows for a slower immobilization rate of biotinylated DNA due to diffusion limitation in the dextran matrix, but with twice the amount of the immobilized DNA due to the greater number of reactive sites, which in turn enables a higher sensitivity for DNA hybridization detection. Interestingly, having a greater DNA probe dispersion in the 3D matrix does not induce a higher DNA hybridization efficiency. In a study of protein binding to immobilized DNA (estrogen receptor to estrogen response elements), aiming at assessing the DNA sequence dependent protein binding behavior, the 2D and 3D chips produce different binding characteristics. On the 2D chip, the protein binding exhibits a better selectivity to the specific sequences, regardless of binding stringency (e.g. salt concentration), whereas on the 3D chip, the liquid handling system needs to be optimized in order to minimize transport limitations and to detect small affinity differences. Through this study we demonstrate that the physicochemical structure of SPR chips affects the apparent binding behaviors of biomolecules. When interpreting SPR binding curves and selecting a sensor chip, these effects should be taken into account.     

Differential protection against oxidative stress and nitric oxide overproduction in cardiovascular and pulmonary systems by propofol during endotoxemia

Background  

Both overproduction of nitric oxide (NO) and oxidative injury of cardiovascular and pulmonary systems contribute to fatal cardiovascular depression during endotoxemia. We investigated in the present study the relative contribution of oxidative stress and NO to cardiovascular depression during different stages of endotoxemia, and delineated their roles in cardiovascular protective effects of a commonly used anesthetic propofol during endotoxemia.     

A new species of the Fejervarya limnocharis complex from Japan (Anura, Dicroglossidae)

We describe a new species of dicroglossid frog of the Fejervarya limnocharis complex from western Honshu, Japan Mainland. The new species, Fejervarya kawamurai, is genetically closer to F. sakishimensis than to F. limnocharis. It differs from F. sakishimensis by smaller tympanum, head, forelimb, hindlimb, foot, and tibia lengths, all relative to snout-vent length, and from F. multistriata by relatively shorter forelimb, hindlimb, foot, and tibia. From F. limnocharis and F. iskandari, it is differentiated by relatively smaller forelimb, hindlimb, foot, and tibia lengths. Taxonomic problems of Fejervarya populations occurring in Central Ryukyus, continental China, and Taiwan are discussed.     

An Upregulation in the Expression of Vanilloid Transient Potential Channels 2 Enhances Hypotonicity-Induced Cytosolic Ca2+ Rise in Human Induced Pluripotent Stem Cell Model of Hutchinson Gillford Progeria

Hutchinson-Gillford Progeria Syndrome (HGPS) is a fatal genetic disorder characterized by premature aging in multiple organs including the skin, musculoskeletal and cardiovascular systems. It is believed that an increased mechanosensitivity of HGPS cells is a causative factor for vascular cell death and vascular diseases in HGPS patients. However, the exact mechanism is unknown. Transient receptor potential (TRP) channels are cationic channels that can act as cellular sensors for mechanical stimuli. The aim of this present study was to examine the expression and functional role of TRP channels in human induced pluripotent stem cell-derived endothelial cells (iPSC-ECs) from the patients with HGPS. The mRNA and protein expression of TRP channels in HGPS and control (IMR90) iPSC-ECs were examined by semi-quantitative RT-PCRs and immunoblots, respectively. Hypotonicity-induced cytosolic Ca²⁺ ([Ca²⁺]_i) rise in iPSC-ECs was measured by confocal microscopy. RT-PCRs and immunoblots showed higher expressional levels of TRPV2 in iPSC-ECs from HGPS patients than those from normal individuals. In functional studies, hypotonicity induced a transient [Ca²⁺]_i rise in iPSC-ECs from normal individuals but a sustained [Ca²⁺]_i elevation in iPSC-ECs from HGPS patients. A nonselective TRPV inhibitor, ruthenium red (RuR, 20 µM), and a specific TRPV2 channel inhibitor, tranilast (100 µM), abolished the sustained phase of hypotonicity-induced [Ca²⁺]_i rise in iPSC-ECs from HGPS patients, and also markedly attenuated the transient phase of the [Ca²⁺]_i rise in these cells. Importantly, a short 10 min hypotonicity treatment caused a substantial increase in caspase 8 activity in iPSC-ECs from HGPS patients but not in cells from normal individuals. Tranilast could also inhibit the hypotonicity-induced increase in caspase 8 activity. Taken together, our data suggest that an up-regulation in TRPV2 expression causes a sustained [Ca²⁺]_i elevation in HGPS-iPSC-ECs under hypotonicity, consequently resulting in apoptotic cell death. This mechanism may contribute to the pathogenesis of vascular diseases in HGPS patients.     

The potential role of mitochondrial dysfunction in seizure-associated cell death in the hippocampus and epileptogenesis

Epilepsy is considered one of the most common neurological disorders worldwide. The burst firing neurons associated with prolonged epileptic discharges could lead to a large number of changes with events of cascades at the cellular level. From its role as the cellular powerhouse, mitochondria also play a crucial role in the mechanisms of cell death. Emerging evidence has shown that prolonged seizures may result in mitochondrial dysfunction and increase of oxidative and nitrosative stress in the hippocampus that precede neuronal cell death and cause subsequent epileptogenesis. The selective dysfunction of mitochondrial respiratory chain Complex I has been suggested to be a biochemical hallmark of seizure-induced neuronal cell death and epileptogenesis. Therefore, protection of mitochondria from bioenergetic failure and oxidative stress in the hippocampus may open a new vista to the development of effective neuroprotective strategies against seizure-induced brain damage and to the design of novel treatment perspectives against therapy-resistant forms of epilepsy.     

Relationships in the Drosophila obscura species group, inferred from mitochondrial cytochrome oxidase II sequences

We compare the sequences for the mitochondrial cytochrome oxidase II gene of 13 species of the Drosophila obscura group. The survey includes six members of the D. affinis subgroup, four of the D. pseudoobscura subgroup, and three of the D. obscura subgroup. In all species, the gene is 688 nucleotides in length, encoding a protein of 229 amino acids plus the first position T of the stop codon. The sequences show the typical high-transition bias for closely related species, but that bias is essentially eliminated for species pairs of > 5% sequence divergence. The phylogenetic relationships in the species group are inferred using both neighbor-joining and maximum parsimony. The two procedures give comparable results, showing that the D. affinis and D. pseudoobscura subgroups are monophyletic groupings that appear to have closer affinities to one another than either has to the D. obscura subgroup. We use transversion distances to estimate times of divergence, on the basis of three different estimates of the time of separation of the D. obscura species group from the D. melanogaster group. If that event occurred 35 Mya, then we can estimate the origin of the nearctic forms at approximately 22 Mya and the separation of the D. affinis and D. pseudoobscura subgroups at approximately 17 Mya.