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1.
Artigo em Inglês | MEDLINE | ID: mdl-38580732

RESUMO

RATIONALE: Internally perceived stimuli evoked by morphine administration can form Pavlovian associations such that they can function as occasion setters (OSs) for externally perceived reward cues in rats, coming to modulate reward-seeking behaviour. Though much research has investigated mechanisms underlying opioid-related reinforcement and analgesia, neurotransmitter systems involved in the functioning of opioids as Pavlovian interoceptive discriminative stimuli remain to be disentangled despite documented differences in the development of tolerance to analgesic versus discriminative stimulus effects. OBJECTIVES: Dopamine has been implicated in many opioid-related behaviours, so we aimed to investigate the role of this neurotransmitter in expression of morphine occasion setting. METHODS: Male and female rats were assigned to positive- (FP) or negative-feature (FN) groups and received an injection of morphine or saline before each training session. A 15-s white noise conditioned stimulus (CS) was presented 8 times during every training session; offset of this stimulus was followed by 4-s access to liquid sucrose on morphine, but not saline, sessions for FP rats. FN rats learned the reverse contingency. Following stable discrimination, rats began generalization testing for expression of morphine-guided sucrose seeking after systemic pretreatment with different doses of the non-selective dopamine receptor antagonist, flupenthixol, and the non-selective dopamine receptor agonist, apomorphine, combined with training doses of morphine or saline in a Latin-square design. RESULTS: The morphine discrimination was acquired under both FP and FN contingencies by males and females. Neither flupenthixol nor apomorphine at any dose substituted for morphine, but both apomorphine and flupenthixol disrupted expression of the morphine OS. This inhibition was specific to sucrose seeking during CS presentations rather than during the period before CS onset and, in the case of apomorphine more so than flupenthixol, to trials on which access to sucrose was anticipated. CONCLUSIONS: Our findings lend support to a mechanism of occasion setting involving gating of CS-induced dopamine release rather than by direct dopaminergic modulation by the morphine stimulus.

2.
Comp Med ; 74(1): 3-11, 2024 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-38532262

RESUMO

L-368,899 is a selective small-molecule oxytocin receptor (OXTR) antagonist originally developed in the 1990s to prevent preterm labor. Although its utility for that purpose was limited, L-368,899 is now one of the most commonly used drugs in animal research for the selective blockade of neural OXTR after peripheral delivery. A growing number of rodent and primate studies have used L-368,899 to evaluate whether certain behaviors are oxytocin dependent. These studies have improved our understanding of oxytocin's function in the brains of rodents and monkeys, but very little work has been done in other mammals, and only a single paper in macaques has provided any evidence that L-368,899 can be detected in the CNS after peripheral delivery. The current study sought to extend those findings in a novel species: coyotes ( Canis latrans ). Coyotes are ubiquitous North American canids that form long-term monogamous pair-bonds. Although monogamy is rare in rodents and primates, all wild canid species studied to date exhibit social monogamy. Coyotes are therefore an excellent model organism for the study of oxytocin and social bonds. Our goal was to determine whether L-368,899 is a viable candidate for future use in behavioral studies in coyotes. We used captive coyotes at the USDA National Wildlife Research Center's Predator Research Facility to evaluate the pharmacokinetics of L-368,899 in blood and CSF during a 90-min time course after intramuscular injection. We then characterized the binding affinity and selectivity of L-368,899 to coyote OXTR and the structurally similar vasopressin 1a receptor. We found that L-368,899 peaked in CSF at 15 to 30 min after intramuscular injection and slowly accumulated in blood. L-368,899 was 40 times more selective for OXTR than vasopressin 1a receptors and bound to the coyote OXTR with an affinity of 12 nM. These features of L-368,899 support its utility in future studies to probe the oxytocin system of coyotes.


Assuntos
Canfanos , Coiotes , Piperazinas , Receptores de Ocitocina , Animais , Coiotes/fisiologia , Ocitocina , Primatas , Vasopressinas
3.
Viruses ; 16(2)2024 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-38400027

RESUMO

Herpes simplex virus 1 (HSV-1) causes significant morbidity and death in humans worldwide. Herpes simplex virus 1 has a complex fusion mechanism that is incompletely understood. The HSV-1 strain ANG has notable fusion and entry activities that distinguish it from wild type. HSV-1 ANG virions fused with the Vero cell surface at 4 °C and also entered cells more efficiently at 15 °C, relative to wild type HSV-1 strain KOS virions, consistent with a hyperfusogenic phenotype. Understanding the molecular basis for the unique entry and fusion activities of HSV-1 strain ANG will help decipher the HSV fusion reaction and entry process. Sequencing of HSV-1 ANG genes revealed multiple changes in gB, gC, gD, gH, and gL proteins relative to wild type HSV-1 strains. The ANG UL45 gene sequence, which codes for a non-essential envelope protein, was identical to wild type KOS. HSV-1 ANG gB, gD, and gH/gL were necessary and sufficient to mediate cell-cell fusion in a virus-free reporter assay. ANG gB, when expressed with wild type KOS gD and gH/gL, increased membrane fusion, suggesting that ANG gB has hyperfusogenic cell-cell fusion activity. Replacing the KOS gD, gH, or gL with the corresponding ANG alleles did not enhance cell-cell fusion. The novel mutations in the ANG fusion and entry glycoproteins provide a platform for dissecting the cascade of interactions that culminate in HSV fusion and entry.


Assuntos
Herpesvirus Humano 1 , Humanos , Animais , Chlorocebus aethiops , Herpesvirus Humano 1/genética , Herpesvirus Humano 1/metabolismo , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismo , Fusão Celular , Glicoproteínas/genética , Glicoproteínas/metabolismo , Células Vero , Internalização do Vírus , Fusão de Membrana
4.
Am J Physiol Renal Physiol ; 326(1): F135-F142, 2024 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-37942539

RESUMO

Several human studies have used the mitochondrial antioxidant MitoQ. Recent in vitro data indicating that MitoQ may induce nephrotoxicity caused concern regarding the safety of MitoQ on the kidneys, but the doses were supraphysiological. Therefore, we sought to determine whether acute MitoQ elicits changes in urinary biomarkers associated with tubular injury in healthy adults with our hypothesis being there would be no changes. Using a randomized crossover design, 32 healthy adults (16 females and 16 males, 29 ± 11 yr old) consumed MitoQ (100-160 mg based on body mass) or placebo capsules. We obtained serum samples and a 4- to 6-h postcapsule consumption urine sample. We assessed creatinine clearance and urine kidney injury biomarkers including the chitinase 3-like-1 gene product YKL-40, kidney-injury marker-1, monocyte chemoattractant protein-1, epidermal growth factor, neutrophil gelatinase-associated lipocalin, interleukin-18, and uromodulin using multiplex assays. We used t tests, Wilcoxon tests, and Hotelling's T2 to assess global differences in urinary kidney injury markers between conditions. Acute MitoQ supplementation did not influence urine flow rate (P = 0.086, rrb = 0.39), creatinine clearance (P = 0.085, rrb = 0.42), or urinary kidney injury markers (T22,8 = 30.6, P = 0.121, univariate ps > 0.064). Using exploratory univariate analysis, MitoQ did not alter individual injury markers compared with placebo (e.g., placebo vs. MitoQ: YKL-40, 507 ± 241 vs. 442 ± 236 pg/min, P = 0.241; kidney injury molecule-1, 84.1 ± 43.2 vs. 76.2 ± 51.2 pg/min, P = 0.890; and neutrophil gelatinase-associated lipocalin, 10.8 ± 10.1 vs. 9.83 ± 8.06 ng/min, P = 0.609). In conclusion, although longer-term surveillance and data are needed in clinical populations, our findings suggest that acute high-dose MitoQ had no effect on urinary kidney injury markers in healthy adults.NEW & NOTEWORTHY We found acute high-dose mitochondria-targeted antioxidant (MitoQ) supplementation was not nephrotoxic and had no effect on markers of acute kidney injury in healthy adults. These findings can help bolster further confidence in the safety of MitoQ, particularly for future investigations seeking to examine the role of mitochondrial oxidative stress, via acute MitoQ supplementation, on various physiological outcomes.


Assuntos
Injúria Renal Aguda , Antioxidantes , Masculino , Adulto , Feminino , Humanos , Lipocalina-2/metabolismo , Estudos Cross-Over , Proteína 1 Semelhante à Quitinase-3/metabolismo , Antioxidantes/metabolismo , Creatinina/metabolismo , Rim/metabolismo , Injúria Renal Aguda/induzido quimicamente , Injúria Renal Aguda/diagnóstico , Biomarcadores/urina
5.
bioRxiv ; 2023 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-38106075

RESUMO

Herpes simplex virus 1 (HSV-1) causes significant morbidity and death in humans worldwide. Herpes simplex virus 1 has a complex fusion mechanism that is incompletely understood. The HSV-1 strain ANG has notable fusion and entry activities that distinguish it from wild type. HSV-1 ANG virions fused with the Vero cell surface at 4°C and also entered cells more efficiently at 15°C relative to wild type virions, consistent with a hyperfusogenic phenotype. Understanding the molecular basis for the unique entry and fusion activities of HSV-1 strain ANG will help decipher the HSV fusion reaction and entry process. Sequencing of HSV-1 ANG genes revealed multiple changes in gB, gC, gD, gH, and gL proteins relative to wild type HSV-1 strains. The ANG UL45 gene sequence, which codes for a non-essential envelope protein, was identical to wild type. HSV-1 ANG gB, gD, and gH/gL were necessary and sufficient to mediate cell-cell fusion in a virus-free reporter assay. ANG gB, when expressed with wild type gD and gH/gL, increased membrane fusion, suggesting that ANG gB has hyperfusogenic cell-cell fusion activity. Replacing the wild type gD, gH, or gL with the corresponding ANG alleles did not enhance cell-cell fusion. Wild type gC is proposed to facilitate fusion and entry into epithelial cells by optimizing conformational changes in the fusion protein gB. ANG gC substitution or addition also had no effect on cell-cell fusion. The novel mutations in the ANG fusion and entry glycoproteins provide a platform for dissecting the cascade of interactions that culminate in HSV fusion and entry.

6.
Vaccine ; 2023 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-37833124

RESUMO

CatSper is a voltage dependent calcium ion channel present in the principal piece of sperm tail. It plays a crucial role in sperm hyperactivated motility and so in fertilization. Extracellular loops of mouse sperm CatSper were used to develop a vaccine to achieve protection from pregnancy. These loops were inserted at one of the three hypervariable regions of Human Papilloma Virus (HPV) capsid protein (L1). Recombinant vaccines were expressed in E.coli as inclusion body (IB), purified, refolded and assembled into virus-like particles (VLP) in vitro, and adsorbed on alum. Four vaccine candidates were tested in Balb/C mice. All the constructs proved immunogenic, one showed contraceptive efficacy. This recombinant contraceptive vaccine is a non-hormonal intervention and is expected to give long-acting protection from undesired pregnancies.

7.
Am J Physiol Heart Circ Physiol ; 325(6): H1418-H1429, 2023 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-37861651

RESUMO

Females typically exhibit lower blood pressure (BP) during exercise than males. However, recent findings indicate that adjusting for maximal strength attenuates sex differences in BP during isometric handgrip (HG) exercise and postexercise ischemia (PEI; metaboreflex isolation). In addition, body size is associated with HG strength but its contribution to sex differences in exercising BP is less appreciated. Therefore, the purpose of this study was to determine whether adjusting for strength and body size would attenuate sex differences in BP during HG and PEI. We obtained beat-to-beat BP in 110 participants (36 females, 74 males) who completed 2 min of isometric HG exercise at 40% of their maximal voluntary contraction followed by 3 min of PEI. In a subset (11 females, 17 males), we collected muscle sympathetic nerve activity (MSNA). Statistical analyses included independent t tests and mixed models (sex × time) with covariate adjustment for 40% HG force, height2, and body surface area. Females exhibited a lower absolute 40% HG force than male participants (Ps < 0.001). Females exhibited lower Δsystolic, Δdiastolic, and Δmean BPs during HG and PEI than males (e.g., PEI, Δsystolic BP, 15 ± 11 vs. 23 ± 14 mmHg; P = 0.004). After covariate adjustment, sex differences in BP responses were attenuated. There were no sex differences in MSNA. In a smaller strength-matched cohort, there was no sex × time interactions for BP responses (e.g., PEI systolic BP, P = 0.539; diastolic BP, P = 0.758). Our data indicate that sex differences in exercising BP responses are attenuated after adjusting for muscle strength and body size.NEW & NOTEWORTHY When compared with young males, females typically exhibit lower blood pressure (BP) during exercise. Adjusting for maximal strength attenuates sex differences in BP during isometric handgrip (HG) exercise and postexercise ischemia (PEI), but the contribution of body size is unknown. Novel findings include adjustments for muscle strength and body size attenuate sex differences in BP reactivity during exercise and PEI, and sex differences in body size contribute to HG strength differences.


Assuntos
Força da Mão , Caracteres Sexuais , Humanos , Masculino , Feminino , Adulto Jovem , Força da Mão/fisiologia , Reflexo , Pressão Sanguínea/fisiologia , Sistema Nervoso Simpático , Isquemia , Tamanho Corporal , Músculo Esquelético/inervação , Frequência Cardíaca
8.
medRxiv ; 2023 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-37745604

RESUMO

Background: Ambulatory blood pressure (BP) monitoring measures nighttime BP and BP dipping, which are superior to in-clinic BP for predicting cardiovascular disease (CVD), the leading cause of death in America. Compared with other racial/ethnic groups, Black Americans exhibit elevated nighttime BP and attenuated BP dipping, including in young adulthood. Social determinants of health contribute to disparities in CVD risk, but the contribution of neighborhood deprivation on nighttime BP is unclear. Therefore, we examined associations between neighborhood deprivation with nighttime BP and BP dipping in young Black and White adults. Methods: We recruited 21 Black and 26 White participants (20 M/27 F, mean age: 21 years, body mass index: 25±4 kg/m2) for 24-hour ambulatory BP monitoring. We assessed nighttime BP and BP dipping (nighttime:daytime BP ratio). The area deprivation index (ADI) was used to measure neighborhood deprivation. Associations between ADI and ambulatory BP were examined. Results: Black participants exhibited higher nighttime diastolic BP compared with White participants (63±8 mmHg vs 58±7 mmHg, p=0.003), and attenuated BP dipping ratios for both systolic (0.92±0.06 vs 0.86±0.05, p=0.001) and diastolic BP (0.86±0.09 vs 0.78±0.08, p=0.007). Black participants experienced greater neighborhood deprivation compared with White participants (ADI scores: 110±8 vs 97±21, p<0.001), and ADI was associated with attenuated systolic BP dipping (ρ=0.342, p=0.019). Conclusions: Our findings suggest neighborhood deprivation may contribute to higher nighttime BP and attenuated BP dipping, which are prognostic of CVD, and more prevalent in Black adults. Targeted interventions to mitigate the effects of neighborhood deprivation may help to improve nighttime BP. Clinical Trial Registry: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04576338.

9.
Am J Clin Nutr ; 118(4): 822-833, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37619651

RESUMO

BACKGROUND: Inadequate hydration is associated with cardiovascular and kidney disease morbidity and all-cause mortality. Compared with White individuals, Black individuals exhibit a higher prevalence of inadequate hydration, which may contribute to racial health disparities. However, the underlying reasons for these differences in hydration remain unclear. OBJECTIVE: This cross-sectional study aimed to investigate whether neighborhood deprivation contributes to racial differences in hydration status. METHODS: We assessed 24 Black and 30 White college students, measuring 24-hour urine osmolality, urine flow rate, urine specific gravity, and plasma copeptin concentration. Participants recorded their food and fluid intake for 3 d to assess total water intake from food and beverages. Neighborhood socioeconomic deprivation was measured using a tract-level Area Deprivation Index. RESULTS: Black participants exhibited higher urine osmolality (640 [314] compared with 440 [283] mOsm/kg H2O, respectively, P = 0.006) and lower urine flow rate (1.06 [0.65] compared with 1.71 [0.89] ml/min, respectively, P = 0.009) compared with White participants, indicating greater hypohydration among Black participants. Black participants reported lower total water intake from food and beverages than White participants (2.3 ± 0.7 compared with 3.5 ± 1.1 L/day, respectively, P < 0.01). Black participants exhibited higher copeptin than White participants (6.3 [3.1] compared with 4.5 [2.3] pmol/L, P = 0.046), and urine osmolality mediated 67% of the difference (P = 0.027). Black participants reported greater cumulative exposure to neighborhood deprivation during childhood (ages 0-18 y). Furthermore, neighborhood deprivation during childhood was associated with urine specific gravity (P = 0.031) and total water intake from food and beverages (P = 0.042) but did not mediate the racial differences in these measures. CONCLUSION: Our data suggest that compared with White young adults, Black young adults are hypohydrated and exhibit higher plasma copeptin concentration, and that greater neighborhood deprivation is associated with chronic underhydration irrespective of race. This trial was registered at clinicaltrials.gov as NCT04576338.


Assuntos
Ingestão de Líquidos , Urinálise , Humanos , Adulto Jovem , Estudos Transversais , Fatores Raciais , Concentração Osmolar
10.
Transl Psychiatry ; 12(1): 372, 2022 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-36075922

RESUMO

The disease burden and healthcare costs of psychiatric diseases along with the pursuit to understand their underlying biochemical mechanisms have led to psychiatric biomarker investigations. Current advances in evaluating candidate biomarkers for psychiatric diseases, such as major depressive disorder (MDD), focus on determining a specific biomarker signature or profile. The origins of candidate biomarkers are heterogenous, ranging from genomics, proteomics, and metabolomics, while incorporating associations with clinical characterization. Prior to clinical use, candidate biomarkers must be validated by large multi-site clinical studies, which can be used to determine the ideal MDD biomarker signature. Therefore, identifying valid biomarkers has been challenging, suggesting the need for alternative approaches. Following validation studies, new technology must be employed to transition from biomarker discovery to diagnostic biomolecular profiling. Current technologies used in discovery and validation, such as mass spectroscopy, are currently limited to clinical research due to the cost or complexity of equipment, sample preparation, or measurement analysis. Thus, other technologies such as electrochemical detection must be considered for point-of-care (POC) testing with the needed characteristics for physicians' offices. This review evaluates the advantages of using electrochemical sensing as a primary diagnostic platform due to its rapidity, accuracy, low cost, biomolecular detection diversity, multiplexed capacity, and instrument flexibility. We evaluate the capabilities of electrochemical methods in evaluating current candidate MDD biomarkers, individually and through multiplexed sensing, for promising applications in detecting MDD biosignatures in the POC setting.


Assuntos
Transtorno Depressivo Maior , Biomarcadores , Transtorno Depressivo Maior/diagnóstico , Eletroquímica , Humanos , Metabolômica/métodos , Proteômica/métodos
11.
J Virol ; 96(13): e0035322, 2022 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-35678603

RESUMO

Monoclonal antibodies are increasingly used for the prevention and/or treatment of viral infections. One caveat of their use is the ability of viruses to evolve resistance to antibody binding and neutralization. Computational strategies to identify viral mutations that may disrupt antibody binding would leverage the wealth of viral genomic sequence data to monitor for potential antibody-resistant mutations. The respiratory syncytial virus is an important pathogen for which monoclonal antibodies against the fusion (F) protein are used to prevent severe disease in high-risk infants. In this study, we used an approach that combines molecular dynamics simulations with FoldX to estimate changes in free energy in F protein folding and binding to the motavizumab antibody upon each possible amino acid change. We systematically selected 8 predicted escape mutations and tested them in an infectious clone. Consistent with our F protein stability predictions, replication-effective viruses were observed for each selected mutation. Six of the eight variants showed increased resistance to neutralization by motavizumab. Flow cytometry was used to validate the estimated (model-predicted) effects on antibody binding to F. Using surface plasmon resonance, we determined that changes in the on-rate of motavizumab binding were associated with the reduced affinity for two novel escape mutations. Our study empirically validated the accuracy of our molecular modeling approach and emphasized the role of biophysical protein modeling in predicting viral resistance to antibody-based therapeutics that can be used to monitor the emergence of resistant viruses and to design improved therapeutic antibodies. IMPORTANCE Respiratory syncytial virus (RSV) causes severe disease in young infants, particularly those with heart or lung diseases or born prematurely. Because no vaccine is currently available, monoclonal antibodies are used to prevent severe RSV disease in high-risk infants. While it is known that RSV evolves to avoid recognition by antibodies, screening tools that can predict which changes to the virus may lead to antibody resistance are greatly needed.


Assuntos
Modelos Moleculares , Mutação , Infecções por Vírus Respiratório Sincicial , Vírus Sincicial Respiratório Humano , Proteínas Virais de Fusão , Anticorpos Antivirais/metabolismo , Humanos , Infecções por Vírus Respiratório Sincicial/virologia , Vírus Sincicial Respiratório Humano/genética , Vírus Sincicial Respiratório Humano/imunologia , Proteínas Virais de Fusão/genética
13.
ACS Appl Polym Mater ; 2(11): 5086-5093, 2020 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-34651131

RESUMO

A reusable sensor architecture, through the combination of self-assembled monolayers and cyclodextrin supramolecular interactions, is demonstrated for class recognition of hydrophobic analytes demonstrated with trans-resveratrol. The reloadable sensor is based on reversible immobilization of α-cyclodextrin on polyethylene glycol surface. α-cyclodextrins complexes with polyethylene glycols and causes the polymer chains to change their surface configuration. The reproducibility and stability of the sur-face, in the detection of nanomolar concentrations of trans-resveratrol, can be demonstrated by electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, and Attenuated total reflectance-Fourier transform infrared spectroscopy. We propose that during sensor operation, α-cyclodextrin decouples from the poly-ethylene glycol surface to complex with trans-resveratrol in solution, and after use, the surface regeneration is conducted with a simple α-cyclodextrin soak. To test the nonspecific response, the sensor was also tested with trans-resveratrol spiked human urine.

14.
Ir Med J ; 111(3): 714, 2018 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-30376232

RESUMO

Type 1 diabetes (T1D) symptoms are subtle and easily overlooked. Delayed diagnosis can result in Diabetic ketoacidosis (DKA), a life threatening complication with lasting consequences. We sought to define the presenting features of T1D and DKA frequency, in children <15 years diagnosed in a single national tertiary centre, and identify predictive factors for DKA. A review of T1D incident cases was undertaken from 2008-2012 using the National Diabetes Register (ICDNR) and clinical case notes. Data were compared with a 1997/8 national study. We found DKA at presentation in 28.7 % of children and 15.5% had moderate/severe DKA. Commonest symptoms were polydipsia, polyuria, weight loss, and lethargy. Median symptom duration was 17 days. Clinical presentation was similar and frequency of DKA at T1D diagnosis remains high. The proportion with moderate/severe DKA is lower than the 25% previously reported (p=0.038). National monitoring and targeted action to reduce DKA at diagnosis is required.


Assuntos
Cetoacidose Diabética/diagnóstico , Cetoacidose Diabética/epidemiologia , Adolescente , Criança , Pré-Escolar , Diagnóstico Tardio , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/diagnóstico , Diabetes Mellitus Tipo 1/epidemiologia , Cetoacidose Diabética/etiologia , Cetoacidose Diabética/fisiopatologia , Feminino , Humanos , Incidência , Lactente , Irlanda/epidemiologia , Masculino , Sistema de Registros/estatística & dados numéricos , Estudos Retrospectivos , Índice de Gravidade de Doença , Fatores de Tempo
15.
Proc Natl Acad Sci U S A ; 115(30): E6978-E6986, 2018 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-29987033

RESUMO

The average cell size of marine phytoplankton is critical for the flow of energy and nutrients from the base of the food web to higher trophic levels. Thus, the evolutionary succession of primary producers through Earth's history is important for our understanding of the radiation of modern protists ∼800 million years ago and the emergence of eumetazoan animals ∼200 million years later. Currently, it is difficult to establish connections between primary production and the proliferation of large and complex organisms because the mid-Proterozoic (∼1,800-800 million years ago) rock record is nearly devoid of recognizable phytoplankton fossils. We report the discovery of intact porphyrins, the molecular fossils of chlorophylls, from 1,100-million-year-old marine black shales of the Taoudeni Basin (Mauritania), 600 million years older than previous findings. The porphyrin nitrogen isotopes (δ15Npor = 5.6-10.2‰) are heavier than in younger sedimentary sequences, and the isotopic offset between sedimentary bulk nitrogen and porphyrins (εpor = -5.1 to -0.5‰) points to cyanobacteria as dominant primary producers. Based on fossil carotenoids, anoxygenic green (Chlorobiacea) and purple sulfur bacteria (Chromatiaceae) also contributed to photosynthate. The low εpor values, in combination with a lack of diagnostic eukaryotic steranes in the time interval of 1,600-1,000 million years ago, demonstrate that algae played an insignificant role in mid-Proterozoic oceans. The paucity of algae and the small cell size of bacterial phytoplankton may have curtailed the flow of energy to higher trophic levels, potentially contributing to a diminished evolutionary pace toward complex eukaryotic ecosystems and large and active organisms.


Assuntos
Organismos Aquáticos/fisiologia , Chlorobi/genética , Chromatiaceae/genética , Ecossistema , Evolução Molecular , Porfirinas/genética , Microbiologia da Água , Chlorobi/metabolismo , Porfirinas/metabolismo
16.
Br J Surg ; 105(11): 1408-1416, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29999515

RESUMO

BACKGROUND: Hilar cholangiocarcinoma is staged using the AJCC staging system. Numerous other prognostically important histopathological and demographic characteristics have been reported. The objective of this meta-analysis was to assess statistically the effect of postresectional tumour characteristics on overall survival of patients undergoing attempted radical curative resection for hilar cholangiocarcinoma. METHODS: Relevant studies were identified by searching the Ovid MEDLINE and PubMed databases. The search was limited to studies published between 2009 and 2017. Papers referring to intrahepatic or distal cholangiocarcinoma were excluded from review. Data extraction used standard Parmar modifications to determine pooled univariable hazard ratios (HRs). RESULTS: Twenty-four articles, containing 4599 patients, were assessed quantitatively. In pooled analyses, age (HR 1·16, 95 per cent c.i. 1·04 to 1·28), T category (HR 1·49, 1·30 to 1·70), lymph node involvement (HR 1·78, 1·65 to 1·93), microvascular invasion (HR 1·49, 1·34 to 1·68), perineural invasion (HR 1·54, 1·40 to 1·68) and tumour differentiation (HR 1·54, 1·38 to 1·72) were significant prognostic factors, with low heterogeneity. Portal vein resection (HR 1·54, 1·15 to 1·70) and resection margin status (HR 1·77, 1·57 to 1·99) had significant effects, but with high heterogeneity. Sex, tumour size and preoperative carbohydrate antigen 19-9 levels did not have a statistically significant effect on postoperative prognosis. CONCLUSION: Several tumour biological variables not included in the seventh edition of the AJCC classification affect overall survival. These require incorporation into prognostic models to ensure a personalized approach to prognostication and treatment.


Assuntos
Neoplasias dos Ductos Biliares/mortalidade , Ductos Biliares Intra-Hepáticos , Colangiocarcinoma/mortalidade , Hepatectomia , Neoplasias dos Ductos Biliares/diagnóstico , Neoplasias dos Ductos Biliares/cirurgia , Colangiocarcinoma/diagnóstico , Colangiocarcinoma/cirurgia , Saúde Global , Humanos , Estadiamento de Neoplasias , Prognóstico , Taxa de Sobrevida/tendências
17.
Eur J Surg Oncol ; 42(5): 591-603, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27005885

RESUMO

INTRODUCTION: As a result of increasing use of implant-based breast reconstruction, complications such as infection are being encountered more frequently. Surgical Site Infections (SSIs) cause morbidity for the patient, can lead to capsular contracture or implant loss and are costly to healthcare systems. National Guidelines suggesting methods to reduce SSI related complications have been produced, but are limited in the scope of interventions covered and underlying evidence presented. METHODS: We performed a literature review encompassing a wide variety of possible SSI prevention strategies. We aimed to present summaries of the available evidence and give pragmatic recommendations as to their validity to use as guidelines for infection prevention strategies for implant-based breast reconstruction. RESULTS: A lack of high quality data relating to the benefit of SSI prevention strategies in implant-based breast reconstruction exists. Many papers relate to orthopaedic implant surgery, or clean surgery in general. Following review of the evidence, sufficient data exists to support use of perioperative antibiotics at implant-based breast reconstruction, with continuation for an extended period in "high risk" patients. Alcohol containing skin preparations should be used over aqueous solutions. Laminar air flow use is suggested. Theatre traffic should be kept to a minimum, as should duration of operative procedure. The implant pocket should be washed prior to implantation. Double gloving and conductive warming are also endorsed. CONCLUSIONS: We have produced a perioperative "Theatre Implant Checklist" for SSI prevention in implant-based breast surgery, with a set of pragmatic up to date guidelines, which allows the reader to evaluate the evidence upon which our recommendations are based.


Assuntos
Implantes de Mama , Mamoplastia , Infecção da Ferida Cirúrgica/prevenção & controle , Lista de Checagem , Medicina Baseada em Evidências , Feminino , Humanos , Guias de Prática Clínica como Assunto
18.
J Phys Condens Matter ; 27(31): 316301, 2015 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-26202454

RESUMO

In this work, the ability of methods based on empirical potentials to simulate the effects of radiation damage in graphite is examined by comparing results for point defects, found using ab initio calculations based on density functional theory (DFT), with those given by two state of the art potentials: the Environment-Dependent Interatomic Potential (EDIP) and the Adaptive Intermolecular Reactive Empirical Bond Order potential (AIREBO). Formation energies for the interstitial, the vacancy and the Stone-Wales (5775) defect are all reasonably close to DFT values. Both EDIP and AIREBO can thus be suitable for the prompt defects in a cascade, for example. Both potentials suffer from arefacts. One is the pinch defect, where two α-atoms adopt a fourfold-coordinated sp(3) configuration, that forms a cross-link between neighbouring graphene sheets. Another, for AIREBO only, is that its ground state vacancy structure is close to the transition state found by DFT for migration. The EDIP fails to reproduce the ground state self-interstitial structure given by DFT, but has nearly the same formation energy. Also, for both potentials, the energy barriers that control diffusion and the evolution of a damage cascade, are not well reproduced. In particular the EDIP gives a barrier to removal of the Stone-Wales defect as 0.9 eV against DFT's 4.5 eV. The suite of defect structures used is provided as supplementary information as a benchmark set for future potentials.

19.
Ir Med J ; 107(9): 278-81, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25417386

RESUMO

The incidence of Type 1 diabetes (T1D) in childhood and adolescence is increasing globally with few exceptions. To date limited conflicting data has been available regarding diabetes epidemiology in Ireland. We sought to determine the incidence of T1D in those aged under 15 years in the ROI by establishing a prospective national register of incident cases (Irish Childhood Diabetes National Registry (ICDNR)) using a standardised protocol which includes a measure of case ascertainment using capture-recapture methodology. In the period, 489 new cases were identified. All paediatric centres nationally participated. The directly standardised incidence rate was 27.5 per 100,000 per year (95% CIs: 24.0, 30.9) and 26.0 (95% CIs: 22.7, 29.3) in 2008 and 2009 respectively. The ICDNR is widely acceptable, it has confirmed a high incidence of T1D and is vital to monitor changes in disease incidence, optimise resource utilisation and diabetes management in the Irish population.


Assuntos
Diabetes Mellitus Tipo 1 , Adolescente , Pré-Escolar , Diabetes Mellitus Tipo 1/diagnóstico , Diabetes Mellitus Tipo 1/epidemiologia , Feminino , Humanos , Incidência , Recém-Nascido , Irlanda/epidemiologia , Masculino , Sistema de Registros
20.
Oncogene ; 33(45): 5295-302, 2014 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-24909177

RESUMO

Pleuropulmonary blastoma is a rare childhood malignancy of lung mesenchymal cells that can remain dormant as epithelial cysts or progress to high-grade sarcoma. Predisposing germline loss-of-function DICER1 variants have been described. We sought to uncover additional contributors through whole exome sequencing of 15 tumor/normal pairs, followed by targeted resequencing, miRNA analysis and immunohistochemical analysis of additional tumors. In addition to frequent biallelic loss  of TP53 and mutations of NRAS or BRAF in some cases, each case had compound disruption of DICER1: a germline (12 cases) or somatic (3 cases) loss-of-function variant plus a somatic missense mutation in the RNase IIIb domain. 5p-Derived microRNA (miRNA) transcripts retained abnormal precursor miRNA loop sequences normally removed by DICER1. This work both defines a genetic interaction landscape with DICER1 mutation and provides evidence for alteration in miRNA transcripts as a consequence of DICER1 disruption in cancer.


Assuntos
RNA Helicases DEAD-box/genética , Neoplasias Pulmonares/genética , MicroRNAs/genética , Mutação , Blastoma Pulmonar/genética , Ribonuclease III/genética , Proteína Supressora de Tumor p53/genética , Sequência de Bases , Cromossomos Humanos Par 5/genética , RNA Helicases DEAD-box/metabolismo , Variações do Número de Cópias de DNA , Exoma/genética , Feminino , GTP Fosfo-Hidrolases/genética , GTP Fosfo-Hidrolases/metabolismo , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Imuno-Histoquímica , Neoplasias Pulmonares/metabolismo , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , MicroRNAs/química , Conformação de Ácido Nucleico , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas B-raf/metabolismo , Blastoma Pulmonar/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Ribonuclease III/metabolismo , Análise de Sequência de DNA/métodos , Proteína Supressora de Tumor p53/metabolismo
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