Consequences of the saphenous artery denervation under normal and chronically lowered blood pressure in rats

We studied constrictor responses of saphenous artery after sympathetic denervation in normotensive rats and rats with chronic regional hypotension. Abdominal aorta was partially occluded in Wistar rats distally to the renal arteries, lowering blood pressure in the hindquarters by about 40%, a week later to denervate saphenous artery the femoral nerve was cut. The density of periarterial nerve plexus and neurogenic responses of the vessel restored partially in 2 weeks and completely in 6 weeks after the surgery; the chronic hypotension did not modify the dynamics of reinnervation. Arteries of both groups of rats demonstrated higher sensitivity to noradrenaline during 6 weeks after denervation, whereas vessel sensitivity to serotonin was enhanced only in normotensive rats. Therefore, chronic hypotension may prevent postdenervation hypersensitivity of vascular smooth muscle to vasoconstrictors.     

Time-resolved fluoroimmunoassay of potato virus M with monoclonal antibodies

Mouse monoclonal antibodies (MAbs) specific for potato virus M (PVM) were prepared and the properties of three of them were studied. MAb M4C1 is IgG2b, it binds with high affinity to PVM coat protein, to purified virus preparations and recognises PVM in infected potato leaves and tubers. MAb M6D5 is IgG2a and also reacts with PVM coat protein, purified PVM and with PVM in potato leaf and tuber extracts. In double-antibody sandwich ELISA (DAS ELISA) MAbs M4C1 and M6D5 reacted with all 17 PVM isolates tested. MAb M7 is IgG2b and recognises PVM only in indirect dot ELISA on nitrocellulose filters and viral coat protein on Western blots. MAbs against PVM were used as capture antibodies and europium-labelled MAbs as conjugates in time-resolved fluoroimmunoassay (EuTRFIA). The standard EuTRFIA curve of PVM detection is approximately linear over a range of PVM concentrations from 0.5 ng/ml to 1000 ng/ml. The lowest PVM concentration detectable in EuTRFIA was 0.5 ng/ml and correspondingly 6 ng/ml in DAS ELISA. The use of the europium chelate label allows PVM detection in potato leaf and tuber sap at dilutions greater than 10^--⁴ with very low background fluorescence. EuTRFIA with MAbs, with either one or two incubations is about 10–20 times more sensitive for PVM detection than is DAS ELISA. PVM and PVX, mixed with healthy potato tuber sap, were simultaneously tested in a single sample at concentrations lower than 10 ng/ml by double-label TRFIA using europium-labelled MAbs to PVM and samarium-labelled MAbs to PVX.     

Final blood lactate concentration after incremental test and aerobic performance

The goal of this study was to test the hypothesis that, in groups of highly trained endurance athletes (first and junior national teams), the final blood lactate concentration at maximum aerobic performance decreased as their training status increased. This study was performed with 20 physically active volunteers and 45 highly trained middle- and long-distance endurance athletes (speed skaters, triathletes, and cross-country skiers). Significant negative correlations (r = ?0.59 to ?0.87) between the final blood lactate concentration after incremental tests until exhaustion and aerobic performance (anaerobic threshold (AT)) were found only for the groups of highly trained endurance athletes, but not for the group of physically active subjects. It was shown for highly trained speed skaters that the final lactate concentration in their blood decreased and the oxygen consumption at AT increased with an increase in the volume of type I muscle fibers in the working muscle (r = ?0.84 and r = 0.7, respectively).     

Dry immersion effects on the mechanisms of metaboreflex regulation of hemodynamics during exercise

The effects of four-day dry immersion on metaboreflex regulation of hemodynamics were evaluated during local static exercise (30% of the maximum voluntary contraction) of the calf plantar flexors. One group of immersed subjects received low-frequency electrostimulation of their leg muscles to decrease the immersion effect on the EMG of exercising muscles. Metaboreflex regulation was evaluated by comparison of cardiovascular responses to physical loads with and without post-exercise circulatory occlusion. Immersion slightly increased the heart rate (HR) and reduced the systolic blood pressure in resting subjects; however, it did not have a distinct effect on blood pressure (BP) and HR during exercise or metaboreflex potentiation of hemodynamic shifts.     

Effect of strength training on pressor reflex responses from receptors in exercising muscles

The effect of strength training on muscle pressor reflex responses was investigated. Ten young, healthy volunteers and eight arm wrestling athletes performed forearm exercises at 30% of maximal voluntary effort until exhaustion. The exercises were either static or rhythmic, with alternating 20-s periods of muscle contraction and relaxation, followed by postexercise forearm arterial occlusion (PEAO). Heart rate, blood pressure (BP), and sympathetic nerve activity directed to muscle blood vessels (MSNA) were continuously recorded during the exercises. MSNA recordings were obtained from the peroneal nerve using a microneurographic method. During static exercises followed by PEAO, there were no differences in BP or MSNA between athletes and nonathlets. In contrast, a significant decrease in muscle pressor reflex responses was observed in the athletes during rhythmic exercises followed by PEAO. The possible relationship between this effect and changes in muscle energy supply, increased wash-out of metabolites, and reduced sensitivity of the muscle receptors in athletes is discussed.     

Antioxidant function of alternative oxidase in mitochondria of winter wheat during cold hardening

The activity of alternative oxidase (AOX) and generation of reactive oxygen species (ROS) in mitochondria of winter wheat Triticum aestivum L. isolated from seedlings subjected to one (7-day exposure to 2–3°C) and two (7-day exposure to 2–3°C and 2-day exposure to −2°C) phases of a cold hardening has been studied. The antioxidant role of AOX in the first phase of the cold hardening has been determined using inhibitors of respiratory chain. Exposure to low temperature was shown to lead to inhibition of cytochrome pathway in mitochondria, increase of ROS production, and switching of the electron transport to the alternative pathway. Decrease in succinate- and antimycin A-induced ROS generation was found during two phases of cold hardening. This fact may point out to functioning of uncoupling proteins under these conditions. Thus, antioxidant function of AOX during the first phase of cold hardening may be an important component of the cold adaptation mechanism in winter crops. The data suggest that ROS and free fatty acids may be signal molecules regulating the activity of two energy-dissipation systems (AOX and uncoupling proteins).     

Impact of multi-targeted antiretroviral treatment on gut T cell depletion and HIV reservoir seeding during acute HIV infection

Background

Limited knowledge exists on early HIV events that may inform preventive and therapeutic strategies. This study aims to characterize the earliest immunologic and virologic HIV events following infection and investigates the usage of a novel therapeutic strategy.

Methods and Findings

We prospectively screened 24,430 subjects in Bangkok and identified 40 AHI individuals. Thirty Thais were enrolled (8 Fiebig I, 5 Fiebig II, 15 Fiebig III, 2 Fiebig IV) of whom 15 completed 24 weeks of megaHAART (tenofovir/emtricitabine/efavirenz/raltegravir/maraviroc). Sigmoid biopsies were completed in 24/30 at baseline and 13/15 at week 24.At baseline, the median age was 29 years and 83% were MSM. Most were symptomatic (87%), and were infected with R5-tropic (77%) CRF01_AE (70%). Median CD4 was 406 cells/mm³. HIV RNA was 5.5 log₁₀ copies/ml. Median total blood HIV DNA was higher in Fiebig III (550 copy/10⁶ PBMC) vs. Fiebig I (8 copy/10⁶ PBMC) (p = 0.01) while the median %CD4+CCR5+ gut T cells was lower in Fiebig III (19%) vs. Fiebig I (59%) (p = 0.0008).After 24 weeks of megaHAART, HIV RNA levels of <50 copies were achieved in 14/15 in blood and 13/13 in gut. Total blood HIV DNA at week 0 predicted reservoir size at week 24 (p<0.001). Total HIV DNA declined significantly and was undetectable in 3 of 15 in blood and 3 of 7 in gut. Frequency of CD4+CCR5+ gut T cells increased from 41% at baseline to 64% at week 24 (p>0.050); subjects with less than 40% at baseline had a significant increase in CD4+CCR5+ T cells from baseline to week 24 (14% vs. 71%, p = 0.02).

Conclusions

Gut T cell depletion and HIV reservoir seeding increases with progression of AHI. MegaHAART was associated with immune restoration and reduced reservoir size. Our findings could inform research on strategies to achieve HIV drug-free remission.     

Foregut Mesenchyme Contributes Cells to Islets during Pancreatic Development in a 3-Dimensional Avian Model

Current interest in the potential use of pancreatic stem-cells in the treatment of insulin dependent diabetes mellitus has led to increased research into normal pancreatic development. Pancreatic organogenesis involves branching morphogenesis of undifferentiated epithelium within surrounding mesenchyme. Current understanding is that the pancreatic islets develop exclusively from the epithelium of the embryonic buds. However, a cellular contribution to islets by mesenchyme has not been conclusively excluded. We present evidence that the mesenchyme of both the dorsal pancreatic bud and stomach rudiment make a substantial contribution of cells to islets during development in a three-dimensional avian model. These data suggest that mesenchyme can be a source not only of signals but also of cells for the definitive epithelia, making pancreatic organogenesis more akin to that of the kidney than to other endodermal organs. This raises the possibility for the use of mesenchymal cells as stem-or progenitor-cells for islet transplantation.Key Words: islets, stem-cells, development, epithelium, mesenchyme, pancreas, stomach, chick-quail, 3-dimensional, endocrine     

Neurological Response to cART vs. cART plus Integrase Inhibitor and CCR5 Antagonist Initiated during Acute HIV

Objective

To compare central nervous system (CNS) outcomes in participants treated during acute HIV infection with standard combination antiretroviral therapy (cART) vs. cART plus integrase inhibitor and CCR5 antagonist (cART+).

Design

24-week randomized open-label prospective evaluation.

Method

Participants were evaluated then randomized to initiate cART (efavirenz, tenofovir, and either emtricitabine or lamivudine) vs. cART+ (cART plus raltegravir and maraviroc) during acute HIV and re-evaluated at 4, 12 and 24 weeks. We examined plasma and CSF cytokines, HIV RNA levels, neurological and neuropsychological findings, and brain MRS across groups and compared to healthy controls.

Results

At baseline, 62 participants were in Fiebig stages I-V. Randomized groups were similar for mean age (27 vs. 25, p = 0.137), gender (each 94% male), plasma log₁₀ HIV RNA (5.4 vs. 5.6, p = 0.382), CSF log₁₀ HIV RNA (2.35 vs. 3.31, p = 0.561), and estimated duration of HIV (18 vs. 17 days, p = 0.546). Randomized arms did not differ at 24 weeks by any CNS outcome. Combining arms, all measures concurrent with antiretroviral treatment improved, for example, neuropsychological testing (mean NPZ-4 of -0.408 vs. 0.245, p<0.001) and inflammatory markers by MRS (e.g. mean frontal white matter (FWM) choline of 2.92 vs. 2.84, p = 0.045) at baseline and week 24, respectively. Plasma neopterin (p<0.001) and interferon gamma-induced protein 10 (IP-10) (p = 0.007) remained elevated in participants compared to controls but no statistically significant differences were seen in CSF cytokines compared to controls, despite individual variability among the HIV-infected group.

Conclusions

A 24-week course of cART+ improved CNS related outcomes, but was not associated with measurable differences compared to standard cART.     

Nickel(II) complexes stabilized by bis[N-(6-pivalamido-2-pyridylmethyl)]benzylamine: Synthesis and characterization of complexes stabilized by a hydrogen bonding network

Intramolecular hydrogen bonds in metalloproteins are key in directing reactivity yet these effects have been difficult to achieved in synthetic systems. We have been developing a synthetic system that uses hydrogen-bonding interactions to modulate the secondary coordination around a transition metal ion. This was accomplished with the ligand bis[N-(6-pivalamido-2-pyridylmethyl)]benzylamine (H₂pmb), which contains two carboxyamido units appended from pyridine rings. Several nickel complexes were prepared and structurally characterized. In particular, we found that the appended carboxyamido groups either provide intramolecular H-bond donors or can be converted to bind directly to a metal center. We established that the complex Ni^IIH₂pmb(Cl)₂ can be sequentially deprotonated with potassium tert-butoxide, causing coordination of the carboxyamido oxygen atoms and concomitant loss of the chloro ligands. The chloro ligands were also removed with silver(I) salts in the presence of acetate ions and the complex Ni^IIH₂pmb(κ²-OAc)(κ¹-OAc) was isolated, in which an intramolecular H-bonding network occurs between the H₂pmb ligand and the coordinate acetato ligands.