Heart rate variability after radiofrequency ablation of epicardial ganglionated plexuses on the ovine left atrium

Background

Ganglionated plexuses (GP) are terminal parts of cardiac autonomous nervous system (ANS). Radiofrequency ablation (RFA) for atrial fibrillation (AF) possibly affects GP. Changes in heart rate variability (HRV) after RFA can reflect ANS modulation.

Methods

Epicardial RFA of GP on the left atrium (LA) was performed under the general anesthesia in 15 mature Romanov sheep. HRV was used to assess the alterations in autonomic regulation of the heart. A 24???hour ECG monitoring was performed before the ablation, 2 days after it and at each of the 12 following months. Ablation sites were evaluated histologically.

Results

There was an instant change in HRV parameters after the ablation. A standard deviation of all intervals between normal QRS (SDNN), a square root of the mean of the squared differences between successive normal QRS intervals (RMSSD) along with HRV triangular index (TI), low frequency (LF) power and high frequency (HF) power decreased, while LF/HF ratio increased. Both the SDNN, LF power and the HF power changes persisted throughout the 12???month follow???up. Significant decrease in RMSSD persisted only for 3 months, HRV TI for 6 months and increase in LF/HF ratio for 7 months of the follow???up. Afterwards these three parameters were not different from the preprocedural values.

Conclusions

Epicardial RFA of GP’s on the ovine left atrium has lasting effect on the main HRV parameters (SDNN, HF power and LF power). The normalization of RMSSD, HRV TI and LF/HF suggests that HRV after epicardial RFA of GPs on the left atrium might restore over time.

     

Branching patterns of rabbit oculomotor and trochlear nerves demonstrated by Sihler's stain technique

A modified Sihler's stain technique was used to visualize the branching patterns of oculomotor and trochlear nerves. The levator palpebrae, superior rectus, inferior rectus, medial rectus, inferior oblique, superior oblique and tensor trochlea muscles were isolated from the eyes of normal rabbits and processed using modified Sihler's technique. The distributions and terminal ramifications of the oculomotor and trochlear nerves were observed. Two distinct divisions and terminal branches of the oculomotor nerve were shown in detail together with the trochlear nerve distribution. The application of Sihler's technique enables researchers to trace nerve branching within relatively transparent muscles, whereas the nerve fibers are counterstained and clearly visible. This technique could be useful for detailed studies of the motor control of extraocular muscles.     

Chromophore composition of the phycobiliprotein Cr-PC577 from the cryptophyte Hemiselmis pacifica

The cryptophyte phycocyanin Cr-PC577 from Hemiselmis pacifica is a close relative of Cr-PC612 found in Hemiselmis virescens and Hemiselmis tepida. The two biliproteins differ in that Cr-PC577 lacks the major peak at around 612 nm in the absorption spectrum. Cr-PC577 was thus purified and characterized with respect to its bilin chromophore composition. Like other cryptophyte phycobiliproteins, Cr-PC577 is an (αβ)(α′β) heterodimer with phycocyanobilin (PCB) bound to the α-subunits. While one chromophore of the β-subunit is also PCB, mass spectrometry identified an additional chromophore with a mass of 585 Da at position β-Cys-158. This mass can be attributed to either a dihydrobiliverdin (DHBV), mesobiliverdin (MBV), or bilin584 chromophore. The doubly linked bilin at position β-Cys-50 and β-Cys-61 could not be identified unequivocally but shares spectral features with DHBV. We found that Cr-PC577 possesses a novel chromophore composition with at least two different chromophores bound to the β-subunit. Overall, our data contribute to a better understanding of cryptophyte phycobiliproteins and furthermore raise the question on the biosynthetic pathway of cryptophyte chromophores.     

An in-vitro investigation of the effect of perfluorooctane sulphonate on cell lines of embryonic origin

Fluorinated organic compounds, such as perfluorooctane sulfonate, are stable chemicals with a wide range of industrial applications. The potential toxicity of perfluorooctane sulfonate is not well characterized, and even less known are the mechanisms underlying its toxic effects. Perfluorooctane sulfonate change of inner mitochondrial membrane permeability has been implicated as a potential mechanism of toxicity. In this study, we research that perfluorooctane sulfonate effects the expression of Apaf1 and Caspase3 genes in the amnion and fetal lung cell line that initiate the cells to undergo apoptosis. The expression of Caspase3 and Apaf1 was determined by using quantitative RT-PCR. In the study there is significant increase in expression of Caspase3 and Apaf1 in amnion and fetal lung cell line exposed to high dose (p < 0.001, p = 0.004). Also there is significant increase in cell lines exposed for a long period of time to perfluorooctane sulfonate (p = 0.001). But no significant increase was seen in the low doses and exposed for a short period of time. In conclusion, apoptotic gene expression is increase in cells exposed perfluorooctane sulfonate by dose dependent manner was determined. So this work is the first study examines the apoptotic effects of perfluorooctane sulfonate in human embryonic cells it will lead the way to the other topical studies.     

Identification of a detrimental role for NK cells in pneumococcal pneumonia and sepsis in immunocompromised hosts

Gram-positive sepsis is a major disease problem. However, the contribution of various immune cell types to pathogenesis remains unclear. By infecting scid and wild type BALB/c mice with Streptococcus pneumoniae we have found a situation in which natural killer (NK) cells can play a detrimental role in the response to infection. scid mice were found to be significantly more susceptible to local and systemic pneumococcal infection than controls; they had significantly higher bacterial loads, elevated inflammatory responses and more widespread lung pathology. Interestingly, depletion of NK cells in scid mice resulted in significantly lower bacteraemia and inflammatory cytokine production. Infection with pneumococci deficient in pneumolysin revealed the toxin was involved in cytokine production. Overall results indicate that elevated NK cell activity during pneumococcal pneumonia amplifies pulmonary and systemic inflammation, increases bacteraemia and results in poor outcome.     

Periostin Limits Tumor Response to VEGFA Inhibition

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A comparison of the effect of long-term starvation on responses to low-temperature stress by juvenile rainbow (Oncorhynchus mykiss) and brown (Salmo trutta) trout reveal different responses in the two species

Biometric parameters and oxidative stress indicators were measured in liver and muscle samples from rainbow trout and brown trout juveniles exposed to a 45-day starvation period at low water temperature. As a general tendency, hepatic antioxidant enzyme activities in both species increased with fasting to eliminate the harmful effects of reactive oxygen species (ROS). However, the metabolic response to food deprivation in the muscle of each species was different. Lipid peroxidation levels in both species increased with starvation. We concluded that (1) low water temperature enhances ROS production in salmonids because of increased polyunsaturated fatty acid content in the cell membrane; (2) starvation significantly impaired the growth parameters of brown trout, yet the reverse was found for rainbow trout; and (3) despite this negative interaction, brown trout juveniles can physiologically tolerate oxidative stress caused by starvation and can therefore be cultivated under stressful conditions even in their early life stages.     

Clinical Outcomes of Thirteen Patients with Acute Chagas Disease Acquired through Oral Transmission from Two Urban Outbreaks in Northeastern Brazil

Background

Outbreaks of orally transmitted Trypanosoma cruzi continue to be reported in Brazil and are associated with a high mortality rate, mainly due to myocarditis.

Methods

This study is a detailed report on the disease progression of acute Chagas disease in 13 patients who were infected during two micro-outbreaks in two northeastern Brazilian towns. Clinical outcomes as well as EKG and ECHO results are described, both before and after benznidazole treatment.

Results

Fever and dyspnea were the most frequent symptoms observed. Other clinical findings included myalgia, periorbital edema, headache and systolic murmur. Two patients died of cardiac failure before receiving benznidazole treatment. EKG and ECHO findings frequently showed a disturbance in ventricular repolarization and pericardial effusion. Ventricular dysfunction (ejection fraction <55%) was present in 27.3% of patients. After treatment, EKG readings normalized in 91.7% of patients. Ventricular repolarization abnormalities persisted in 50% of the patients, while sinus bradycardia was observed in 18%. The systolic ejection fraction normalized in two out of three patients with initially depressed ventricular function, while pericardial effusion disappeared.

Conclusions

Myocarditis is frequently found and potentially severe in patients with acute Chagas disease. Benznidazole treatment may improve clinical symptoms, as well as EKG and ECHO findings.     

A dehydration avoidance mechanism: Leaf rolling

Plants have several defense mechanisms against unfavorable environmental conditions. One of these mechanisms is leaf rolling. In this review, leaf rolling as a response to water deficit stress and biochemical changes during leaf rolling in higher plants are reported. For instance, the activities of some enzymes and osmotic substances change during leaf rolling. Leaf rolling increases drought resistance in numerous species in theGramineae as well as inCtenanthe setosa, a perennial herbaceous plant that is a suitable model for use in studies of leaf rolling.