Micafungin for Candida Albicans Pacemaker-Associated Endocarditis: A Case Report and Review of the Literature

We report on the treatment with micafungin of a pacemaker-associated endocarditis due to Candida albicans. Antifungal therapy was able to reduce vegetation size from 5 to 1 cm making possible the transvenous removal of the device without a high risk of pulmonary embolism. Noteworthy, a high micafungin concentration was documented into the lead vegetation (10 μg/g of vegetation tissue) and this may have contributed to the striking size reduction of vegetation.     

A marine protected area network does not confer community structure resilience to a marine heatwave across coastal ecosystems

Marine protected areas (MPAs) have gained attention as a conservation tool for enhancing ecosystem resilience to climate change. However, empirical evidence explicitly linking MPAs to enhanced ecological resilience is limited and mixed. To better understand whether MPAs can buffer climate impacts, we tested the resistance and recovery of marine communities to the 2014–2016 Northeast Pacific heatwave in the largest scientifically designed MPA network in the world off the coast of California, United States. The network consists of 124 MPAs (48 no-take state marine reserves, and 76 partial-take or special regulation conservation areas) implemented at different times, with full implementation completed in 2012. We compared fish, benthic invertebrate, and macroalgal community structure inside and outside of 13 no-take MPAs across rocky intertidal, kelp forest, shallow reef, and deep reef nearshore habitats in California's Central Coast region from 2007 to 2020. We also explored whether MPA features, including age, size, depth, proportion rock, historic fishing pressure, habitat diversity and richness, connectivity, and fish biomass response ratios (proxy for ecological performance), conferred climate resilience for kelp forest and rocky intertidal habitats spanning 28 MPAs across the full network. Ecological communities dramatically shifted due to the marine heatwave across all four nearshore habitats, and MPAs did not facilitate habitat-wide resistance or recovery. Only in protected rocky intertidal habitats did community structure significantly resist marine heatwave impacts. Community shifts were associated with a pronounced decline in the relative proportion of cold water species and an increase in warm water species. MPA features did not explain resistance or recovery to the marine heatwave. Collectively, our findings suggest that MPAs have limited ability to mitigate the impacts of marine heatwaves on community structure. Given that mechanisms of resilience to climate perturbations are complex, there is a clear need to expand assessments of ecosystem-wide consequences resulting from acute climate-driven perturbations, and the potential role of regulatory protection in mitigating community structure changes.     

Modulation of airway responses by prostaglandins in young and fully grown rabbits

Maturational changes have been noted in neurally mediated contractile and relaxant responses in airways from New Zealand White rabbits. In this study, we focused on prostaglandins with bronchoprotective properties as potential modulators of airway tone in maturing rabbits. Tracheal rings from 1-, 2-, and 13-wk-old rabbits were assessed for neurally mediated contractile and relaxant responses produced by electrical field stimulation (EFS) of nerves in the presence and absence of the prostaglandin inhibitor, indomethacin (Indo). We also measured EFS-induced release of prostaglandin E(2) (PGE(2)) and the stable metabolite of prostacyclin, 6-keto-prostaglandin F(1alpha) (6-keto-PGF(1alpha)). In the presence of Indo, EFS produced significant increases in contractile responses in segments from 1- and 2-wk-old animals but not in segments from 13-wk adult rabbits. Tracheal rings from 1- and 2-wk-old animals precontracted with neurokinin A (NKA) relaxed 100% in response to EFS when Indo was not in the bath. In rings from 13-wk-old animals, relaxation was 40%. With Indo, relaxation was abolished in 1-wk-old animals and reduced to 30% in the 2- and 13-wk-old groups. Buffer from baths collected after EFS had significant increases in PGE(2) and 6-keto-PGF(1alpha) released from tissues from 1- vs. 2- and 13-wk-old animals. Dose response curves to PGE(2) using tissues precontracted to NKA showed significant increases in relaxant responses in 1- and 2- vs. 13-wk-old rabbits. In rabbit airways, this study demonstrates enhanced modulation of airway tone by PGE(2) and greater release of the bronchoprotective prostaglandins PGE(2) and prostacyclin early in life.     

AMP-activated protein kinase kinase activity and phosphorylation of AMP-activated protein kinase in contracting muscle of sedentary and endurance-trained rats

This study was designed to examine activity of AMP-activated protein kinase kinase (AMPKK) in muscles from nontrained and endurance-trained rats. Rats were trained 5 days/wk, 2 h/day for 8 wk at a final intensity of 32 m/min up a 15% grade with 30-s sprints at 53 m/min every 10 min. Gastrocnemius muscles were stimulated in situ in trained and nontrained rats for 5 min at frequencies of 0.4/s and 1/s. Gastrocnemius LKB1 protein, a putative component of the AMPKK complex (LKB1, STRAD, and MO25), increased approximately twofold in response to training. Phosphorylation of AMP-activated protein kinase (AMPK) determined by Western blot and AMPK activity of immunoprecipitates (both isoforms) was increased at both stimulation rates in both trained and nontrained muscles. AMPKK activity was 73% lower in resuspended polyethylene glycol precipitates of muscle extracts from the trained compared with nontrained rats. AMPKK activity did not increase in either trained or nontrained muscle in response to electrical stimulation, even though phospho-AMPK did increase. These results suggest that AMPKK is activated during electrical stimulation of both trained and nontrained muscle by mechanisms other than covalent modification.     

Dipyridamole reversibly inhibits mengovirus RNA replication

Dipyridamole is an effective inhibitor of cardiovirus growth in cell culture. The effects of dipyridamole on mengovirus replication in vivo and in vitro were examined in the hope the drug could be used as an experimental analog of the poliovirus inhibitor guanidine. Guanidine selectively inhibits poliovirus RNA synthesis but not RNA translation, and as such, has been a valuable research tool. Although guanidine does not inhibit cardiovirus infection, a compound with similar discriminatory characteristics would be experimentally useful for parallel work with these viruses. We found that mengovirus plaque formation in HeLa or L cells was inhibited nearly 100% by the presence of 80 muM dipyridamole. The inhibitory effect was reversible and targeted an early step in the replication cycle. Studies with luciferase-expressing mengovirus replicons showed that viral protein synthesis was unaffected by dipyridamole, and rather, RNA synthesis was the step targeted by the drug. This assessment was confirmed by direct analyses of viral translation and RNA synthesis activities in a Krebs-2-derived in vitro system that supported complete, infectious cardiovirus replication. In Krebs extracts, dipyridamole specifically inhibited viral RNA synthesis to more than 95%, with no concomitant effect on viral protein translation or polyprotein processing. The observed inhibition reversibly affected an early step in both minus-strand and plus-strand RNA synthesis, although inhibition of plus-strand synthesis was more profound than that of minus-strand synthesis. We conclude that dipyridamole is a potent experimental tool that readily distinguishes between cardiovirus translation and RNA replication functions.     

Differential Effect of Helicobacter pylori Eradication on Time‐Trends in Brady/Hypokinesia and Rigidity in Idiopathic Parkinsonism

Background: We examine the effect of eradicating Helicobacter in idiopathic parkinsonism (IP). Marked deterioration, where eradication‐therapy failed, prompted an interim report in the first 20 probands to reach de‐blinding. The null‐hypothesis, “eradication has no effect on principal outcome, mean stride length at free‐walking speed,” was rejected. We report on study completion in all 30 who had commenced post‐treatment assessments. Methods: This is a randomized, placebo‐controlled, parallel‐group efficacy study of eradicating biopsy‐proven (culture and/or organism on histopathology) Helicobacter pylori infection on the time course of facets of IP, in probands taking no, or stable long‐t½, anti‐parkinsonian medication. Persistent infection at de‐blinding (scheduled 1‐year post‐treatment) led to open active eradication‐treatment. Results: Stride length improved (73 (95% CI 14–131) mm/year, p = .01) in favor of “successful” blinded active over placebo, irrespective of anti‐parkinsonian medication, and despite worsening upper limb flexor rigidity (237 (57–416) Nm × 10^?3/year, p = .01). This differential effect was echoed following open active, post‐placebo. Gait did not deteriorate in year 2 and 3 post‐eradication. Anti‐nuclear antibody was present in all four proven (two by molecular microbiology only) eradication failures. In the remainder, it marked poorer response during the year after eradication therapy, possibly indicating residual “low‐density” infection. We illustrate the importance of eradicating low‐density infection, detected only by molecular microbiology, in a proband not receiving anti‐parkinsonian medication. Stride length improved (424 (379–468) mm for 15 months post‐eradication, p = .001), correction of deficit continuing to 3.4 years. Flexor rigidity increased before hydrogen‐breath‐test positivity for small intestinal bacterial overgrowth (208 (28–388) Nm × 10^?3, p = .02), increased further during (171 (67–274), p = .001) (15–31 months), and decreased (136 (6–267), p = .04) after restoration of negativity (32–41 months). Conclusion: Helicobacter is an arbiter of progression, independent of infection‐load.     

Inspiratory-resistive loading increases the ventilatory response to arousal but does not reduce genioglossus muscle activity on the return to sleep

Arousals from sleep are thought to predispose to obstructive sleep apnea by causing hyperventilation and hypocapnia, which reduce airway dilator muscle activity on the return to sleep. However, prior studies of auditory arousals have not resulted in reduced genioglossus muscle activity [GG-electromyogram (EMG)], potentially because airway resistance prior to arousal was low, leading to a small ventilatory response to arousal and minimal hypocapnia. Thus we aimed to increase the ventilatory response to arousal by resistive loading prior to auditory arousal and determine whether reduced GG-EMG occurred on the return to sleep. Eighteen healthy young men and women were recruited. Subjects were instrumented with a nasal mask with a pneumotachograph, an epiglottic pressure catheter, and intramuscular GG-EMG electrodes. Mask CO(2) levels were monitored. Three- to 15-s arousals from sleep were induced with auditory tones after resting breathing (No-Load) or inspiratory-resistive loading (Load; average 8.4 cmH(2)O·l(-1)·s(-1)). Peak minute ventilation following arousal was greater after Load than No-Load (mean ± SE; 8.0 ± 0.6 vs. 7.4 ± 0.6 l/min, respectively). However, the nadir end tidal partial pressure of CO(2) did not differ between Load conditions (43.1 ± 0.6 and 42.8 ± 0.5 mmHg, respectively), and no period of reduced GG activity occurred following the return to sleep (GG-EMG baseline, minimum after Load and No-Load = 2.9 ± 1.2%, 3.1 ± 1.3%, and 3.0 ± 1.3% max, respectively). These findings indicate that the hyperventilation, which occurs following tone-induced arousal, is appropriate for the prevailing level of respiratory drive, because loading did not induce marked hypocapnia or lower GG muscle activity on the return to sleep. Whether similar findings occur following obstructive events in patients remains to be determined.     

Ploidy variation in multinucleate cells changes under stress

Ploidy variation is found in contexts as diverse as solid tumors, drug resistance in fungal infection, and normal development. Altering chromosome or genome copy number supports adaptation to fluctuating environments but is also associated with fitness defects attributed to protein imbalances. Both aneuploidy and polyploidy can arise from multinucleate states after failed cytokinesis or cell fusion. The consequences of ploidy variation in syncytia are difficult to predict because protein imbalances are theoretically buffered by a common cytoplasm. We examined ploidy in a naturally multinucleate fungus, Ashbya gossypii. Using integrated lac operator arrays, we found that chromosome number varies substantially among nuclei sharing a common cytoplasm. Populations of nuclei range from 1N to >4N, with different polyploidies in the same cell and low levels of aneuploidy. The degree of ploidy variation increases as cells age. In response to cellular stress, polyploid nuclei diminish and haploid nuclei predominate. These data suggest that mixed ploidy is tolerated in these syncytia; however, there may be costs associated with variation as stress homogenizes the genome content of nuclei. Furthermore, the results suggest that sharing of gene products is limited, and thus there is incomplete buffering of ploidy variation despite a common cytosol.     

Differential responses of human tumor cell lines to anti-p185HER2 monoclonal antibodies

The HER2 protooncogene encodes a receptor tyrosine kinase, p185^HER2. The overexpression of p185^HER2 has been associated with a worsened prognosis in certain human cancers. In the present work we have screened a variety of different tumor cell lines for p185^HER2 expression using both enzyme-linked immunosorbent and fluorescence-activated cell sorting assays employing murine monoclonal antibodies directed against the extracellular domain of the receptor. Increased levels of p185^HER2 were found in breast (5/9), ovarian (1/6), stomach (2/3) and colorectal (5/16) carcinomas, whereas all kidney and submaxillary adenocarcinoma cell lines tested were negative. Some monoclonal antibodies directed against the extracellular domain of p185^HER2 inhibited growth in monolayer culture of breast and ovarian tumor cell lines overexpressing p185^HER2, but had no effect on the growth of colon or gastric adenocarcinomas expressing increased levels of this receptor. The most potent growth-inhibitory anti-p185^HER2 monoclonal antibody in monolayer culture, designated mumAb 4D5 (a murine IgG1 antibody), was also tested in soft-agar growth assays for activity against p185^HER2-overexpressing tumor cell lines of each type, with similar results. In order to increase the spectrum of tumor types potentially susceptible to monoclonal antibody-mediated anti-p185^HER2 therapies, to decrease potential immunogenicity issues with the use of murine monoclonal antibodies for human therapy, and to provide the potential for antibody-mediated cytotoxic activity, a mouse/human chimeric 4D5 (chmAb 4D5) and a humanized 4D5 (rhu)mAb 4D5 HER2 antibody were constructed. Both engineered antibodies, in combination with human peripheral blood mononuclear cells, elicited antibody-dependent cytotoxic responses in accordance with the level of p185^HER2 expression. Since this cytotoxic activity is independent of sensitivity to mumAb 4D5, the engineered monoclonal antibodies expand the potential target population for antibody-mediated therapy of human cancers characterized by the overexpression of p185^HER2.     

PopART-IBM,a highly efficient stochastic individual-based simulation model of generalised HIV epidemics developed in the context of the HPTN 071 (PopART) trial

Mathematical models are powerful tools in HIV epidemiology, producing quantitative projections of key indicators such as HIV incidence and prevalence. In order to improve the accuracy of predictions, such models need to incorporate a number of behavioural and biological heterogeneities, especially those related to the sexual network within which HIV transmission occurs. An individual-based model, which explicitly models sexual partnerships, is thus often the most natural type of model to choose. In this paper we present PopART-IBM, a computationally efficient individual-based model capable of simulating 50 years of an HIV epidemic in a large, high-prevalence community in under a minute. We show how the model calibrates within a Bayesian inference framework to detailed age- and sex-stratified data from multiple sources on HIV prevalence, awareness of HIV status, ART status, and viral suppression for an HPTN 071 (PopART) study community in Zambia, and present future projections of HIV prevalence and incidence for this community in the absence of trial intervention.