Impact of binding to the multidrug resistance regulator protein LmrR on the photo-physics and -chemistry of photosensitizers

Light activated photosensitizers generate reactive oxygen species (ROS) that interfere with cellular components and can induce cell death, e.g., in photodynamic therapy (PDT). The effect of cellular components and especially proteins on the photochemistry and photophysics of the sensitizers is a key aspect in drug design and the correlating cellular response with the generation of specific ROS species. Here, we show the complex range of effects of binding of photosensitizer to a multidrug resistance protein, produced by bacteria, on the formers reactivity. We show that recruitment of drug like molecules by LmrR (Lactococcal multidrug resistance Regulator) modifies their photophysical properties and their capacity to induce oxidative stress especially in 1O2 generation, including rose bengal (RB), protoporphyrin IX (PpIX), bodipy, eosin Y (EY), riboflavin (RBF), and rhodamine 6G (Rh6G). The range of neutral and charged dyes with different exited redox potentials, are broadly representative of the dyes used in PDT.</p

Granzyme B (GraB) Autonomously Crosses the Cell Membrane and Perforin Initiates Apoptosis and GraB Nuclear Localization

Granzyme B (GraB) induces apoptosis in the presence of perforin. Perforin polymerizes in the cell membrane to form a nonspecific ion pore, but it is not known where GraB acts to initiate the events that ultimately lead to apoptosis. It has been hypothesized that GraB enters the target cell through a perforin channel and then initiates apoptosis by cleaving and activating members of the ICE/Ced-3 family of cell death proteases. To determine if GraB can enter the cell, we treated YAC-1 or HeLa cells with FITC-labeled GraB and measured intracellular fluorescence with a high sensitivity CCD camera and image analyzer. GraB was internalized and found diffusely dispersed in the cell cytoplasm within 10 min. Uptake was inhibited at low temperature (4°C) and by pretreatment with metabolic inhibitors, NaF and DNP, or cytochalasin B, a drug that both blocks microfilament formation, and FITC-GraB remained on the cell membrane localized in patches. With the simultaneous addition of perforin and FITC-GraB, no significant increase in cytoplasmic fluorescence was observed over that found in cells treated only with FITC-GraB. However, FITC-GraB was now detected in the nucleus of apoptotic cells labeling apoptotic bodies and localized areas within and along the nuclear membrane. The ability of GraB to enter cells in the absence of perforin was reexamined using anti-GraB antibody immunogold staining of ultrathin cryosections of cells incubated with GraB. Within 15 min, gold particles were detected both on the plasma membrane and in the cytoplasm of cells with some gold staining adjacent to the nuclear envelope but not in the nucleus. Cells internalizing GraB in the absence of perforin appeared morphologically normal by Hoechst staining and electron microscopy. GraB directly microinjected into the cytoplasm of B16 melanoma cells induced transient plasma membrane blebbing and nuclear coarsening but the cells did not become frankly apoptotic unless perforin was added. We conclude that GraB can enter cells autonomously but that perforin initiates the apoptotic process and the entry of GraB into the nucleus

High prevalence of lipoatrophy in pre-pubertal South African children on antiretroviral therapy : a cross-sectional study

Publication of this article was funded by the Stellenbosch University Open Access Fund.The original publication is available at http://www.biomedcentral.com/bmcpediatrBackground: Despite changes in WHO guidelines, stavudine is still used extensively for treatment of pediatric HIV in the developing world. Lipoatrophy in sub-Saharan African children can be stigmatizing and have far-reaching consequences. The severity and extent of lipoatrophy in pre-pubertal children living in sub-Saharan Africa is unknown. Methods: In this cross-sectional study, children who were 3-12 years old, on antiretroviral therapy and pre-pubertal were recruited from a Family HIV Clinic in South Africa. Lipoatrophy was identified and graded by consensus between two HIV pediatricians using a standardized grading scale. A professional dietician performed formal dietary assessment and anthropometric measurements of trunk and limb fat. Previous antiretroviral exposures were recorded. In a Dual-Energy X-ray Absorbtiometry (DXA) substudy body composition was determined in 42 participants. Results: Among 100 recruits, the prevalence of visually obvious lipoatrophy was 36% (95% CI: 27%–45%). Anthropometry and DXA measurements corroborated the clinical diagnosis of lipoatrophy: Both confirmed significant, substantial extremity fat loss in children with visually obvious lipoatrophy, when adjusted for age and sex. Adjusted odds ratio for developing lipoatrophy was 1.9 (95% CI: 1.3 - 2.9) for each additional year of accumulated exposure to standard dose stavudine. Cumulative time on standard dose stavudine was significantly associated with reductions in biceps and triceps skin-fold thickness (p=0.008). Conclusions: The prevalence of visually obvious lipoatrophy in pre-pubertal South African children on antiretroviral therapy is high. The amount of stavudine that children are exposed to needs review. Resources are needed to enable low-and-middle-income countries to provide suitable pediatric-formulated alternatives to stavudine-based pediatric regimens. The standard stavudine dose for children may need to be reduced. Diagnosis of lipoatrophy at an early stage is important to allow timeous antiretroviral switching to arrest progression and avoid stigmatization. Diagnosis using visual grading requires training and experience, and DXA and comprehensive anthropometry are not commonly available. A simple objective screening tool is needed to identify early lipoatrophy in resourcelimited settings where specialized skills and equipment are not available.Stellenbosch University Open Access FundPublishers' versio

The influences of nursing transformational leadership style on the quality of nurses’ working lives in Taiwan: a cross-sectional quantitative study

- Background: Taiwan’s NHI system is one of the most successful health care models for countries around the globe. However, little research has demonstrated the mental health issues associated with nursing transformational leadership style under the NHI system, especially in the quality of nurses’ working lives in Taiwan. It is important to know the relationship between transformational leadership style and the mental health of nurses, organisational commitment and job satisfaction. The research aimed to understand the influences of nursing transformational leadership style on the quality of nurses’ working lives in Taiwan. The research hypothesis was that transformational leadership styles would have positive influence on the quality of nurses’ working lives. - Methods: This was a cross-sectional quantitative study. Nurses from each type of hospital ownership (private, public and religious) were recruited. Participation was voluntary and signed informed consent was obtained. The inclusion criteria were nurses with at least one year’s work experience in the hospitals. Self-administrated questionnaires were used. A total of 807 participants were contacted and 651 questionnaires were fully completed (response rate 80.7 %). A theory driven model was used to test the research hypotheses using structural equation modelling performed with AMOS 16.0. - Results: Transformational leadership contributes significantly to supervisor support. Workplace support, particularly from the supervisor, is an important mediator variable that explains the relationship between transformational leadership and job satisfaction. Organisational commitment was the strongest factor relevant to the general health well-being in Taiwanese nurses than job satisfaction. The hypothesized positive relationships between transformational leadership and all variables were supported by the data. - Conclusions: Our findings have important consequences for organisational health. Our model demonstrates a complete picture of the work relationships on the quality of nurses’ working lives. The results provided information about the subordinates’ perceptions of transformational nursing leadership styles and mental health outcomes in different hospital settings, as well as identified organisational factors that could improve the quality of nurses’ working lives

Interactions between the adducin 2 gene and antihypertensive drug therapies in determining blood pressure in people with hypertension

<p>Abstract</p> <p>Background</p> <p>As part of the NHLBI Family Blood Pressure Program, the Genetic Epidemiology Network of Arteriopathy (GENOA) recruited 575 sibships (n = 1583 individuals) from Rochester, MN who had at least two hypertensive siblings diagnosed before age 60. Linkage analysis identified a region on chromosome 2 that was investigated using 70 single nucleotide polymorphisms (SNPs) typed in 7 positional candidate genes, including adducin 2 (<it>ADD2</it>).</p> <p>Method</p> <p>To investigate whether blood pressure (BP) levels in these hypertensives (n = 1133) were influenced by gene-by-drug interactions, we used cross-validation statistical methods (i.e., estimating a model for predicting BP levels in one subgroup and testing it in a different subgroup). These methods greatly reduced the chance of false positive findings.</p> <p>Results</p> <p>Eight SNPs in <it>ADD2 </it>were significantly associated with systolic BP in untreated hypertensives (p-value < 0.05). Moreover, we also identified SNPs associated with gene-by-drug interactions on systolic BP in drug-treated hypertensives. The TT genotype at SNP rs1541582 was associated with an average systolic BP of 133 mmHg in the beta-blocker subgroup and 148 mmHg in the diuretic subgroup after adjusting for overall mean differences among drug classes.</p> <p>Conclusion</p> <p>Our findings suggest that hypertension candidate gene variation may influence BP responses to specific antihypertensive drug therapies and measurement of genetic variation may assist in identifying subgroups of hypertensive patients who will benefit most from particular antihypertensive drug therapies.</p

AMP-Activated Kinase Restricts Rift Valley Fever Virus Infection by Inhibiting Fatty Acid Synthesis

The cell intrinsic innate immune responses provide a first line of defense against viral infection, and often function by targeting cellular pathways usurped by the virus during infection. In particular, many viruses manipulate cellular lipids to form complex structures required for viral replication, many of which are dependent on de novo fatty acid synthesis. We found that the energy regulator AMPK, which potently inhibits fatty acid synthesis, restricts infection of the Bunyavirus, Rift Valley Fever Virus (RVFV), an important re-emerging arthropod-borne human pathogen for which there are no effective vaccines or therapeutics. We show restriction of RVFV both by AMPK and its upstream activator LKB1, indicating an antiviral role for this signaling pathway. Furthermore, we found that AMPK is activated during RVFV infection, leading to the phosphorylation and inhibition of acetyl-CoA carboxylase, the first rate-limiting enzyme in fatty acid synthesis. Activating AMPK pharmacologically both restricted infection and reduced lipid levels. This restriction could be bypassed by treatment with the fatty acid palmitate, demonstrating that AMPK restricts RVFV infection through its inhibition of fatty acid biosynthesis. Lastly, we found that this pathway plays a broad role in antiviral defense since additional viruses from disparate families were also restricted by AMPK and LKB1. Therefore, AMPK is an important component of the cell intrinsic immune response that restricts infection through a novel mechanism involving the inhibition of fatty acid metabolism

An intriguing shift occurs in the novel protein phosphatase 1 binding partner, TCTEX1D4: evidence of positive selection in a pika model

T-complex testis expressed protein 1 domain containing 4 (TCTEX1D4) contains the canonical phosphoprotein phosphatase 1 (PPP1) binding motif, composed by the amino acid sequence RVSF. We identified and validated the binding of TCTEX1D4 to PPP1 and demonstrated that indeed this protein is a novel PPP1 interacting protein. Analyses of twenty-one mammalian species available in public databases and seven Lagomorpha sequences obtained in this work showed that the PPP1 binding motif 90RVSF93 is present in all of them and is flanked by a palindromic sequence, PLGS, except in three species of pikas (Ochotona princeps, O. dauurica and O. pusilla). Furthermore, for the Ochotona species an extra glycosylation site, motif 96NLS98, and the loss of the palindromic sequence were observed. Comparison with other lagomorphs suggests that this event happened before the Ochotona radiation. The dN/dS for the sequence region comprising the PPP1 binding motif and the flanking palindrome highly supports the hypothesis that for Ochotona species this region has been evolving under positive selection. In addition, mutational screening shows that the ability of pikas TCTEX1D4 to bind to PPP1 is maintained, although the PPP1 binding motif is disrupted, and the N- and C-terminal surrounding residues are also abrogated. These observations suggest pika as an ideal model to study novel PPP1 complexes regulatory mechanisms.publishe

The descriptive epidemiology of DSM-IV Adult ADHD in the World Health Organization World Mental Health Surveys

We previously reported on the cross-national epidemiology of ADHD from the first 10 countries in the WHO World Mental Health (WMH) Surveys. The current report expands those previous findings to the 20 nationally or regionally representative WMH surveys that have now collected data on adult ADHD. The Composite International Diagnostic Interview (CIDI) was administered to 26,744 respondents in these surveys in high-, upper-middle-, and low-/lower-middle-income countries (68.5% mean response rate). Current DSM-IV/CIDI adult ADHD prevalence averaged 2.8% across surveys and was higher in high (3.6%)- and upper-middle (3.0%)- than low-/lower-middle (1.4%)-income countries. Conditional prevalence of current ADHD averaged 57.0% among childhood cases and 41.1% among childhood subthreshold cases. Adult ADHD was significantly related to being male, previously married, and low education. Adult ADHD was highly comorbid with DSM-IV/CIDI anxiety, mood, behavior, and substance disorders and significantly associated with role impairments (days out of role, impaired cognition, and social interactions) when controlling for comorbidities. Treatment seeking was low in all countries and targeted largely to comorbid conditions rather than to ADHD. These results show that adult ADHD is prevalent, seriously impairing, and highly comorbid but vastly under-recognized and undertreated across countries and cultures

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe