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1.
Ecol Appl ; : e2968, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38562000

RESUMO

Understanding how habitat attributes (e.g., patch area and sizes, connectivity) control recruitment and how this is modified by processes operating at larger spatial scales is fundamental to understanding population sustainability and developing successful long-term restoration strategies for marine foundation species-including for globally threatened reef-forming oysters. In two experiments, we assessed the recruitment and energy reserves of oyster recruits onto remnant reefs of the oyster Saccostrea glomerata in estuaries spanning 550 km of coastline in southeastern Australia. In the first experiment, we determined whether recruitment of oysters to settlement plates in three estuaries was correlated with reef attributes within patches (distances to patch edges and surface elevation), whole-patch attributes (shape and size of patches), and landscape attributes (connectivity). We also determined whether environmental factors (e.g., sedimentation and water temperature) explained the differences among recruitment plates. We also tested whether differences in energy reserves of recruits could explain the differences between two of the estuaries (one high- and one low-sedimentation estuary). In the second experiment, across six estuaries (three with nominally high and three with nominally low sedimentation rates), we tested the hypothesis that, at the estuary scale, recruitment and survival were negatively correlated to sedimentation. Overall, total oyster recruitment varied mostly at the scale of estuaries rather than with reef attributes and was negatively correlated with sedimentation. Percentage recruit survival was, however, similar among estuaries, although energy reserves and condition of recruits were lower at a high- compared to a low-sediment estuary. Within each estuary, total oyster recruitment increased with patch area and decreased with increasing tidal height. Our results showed that differences among estuaries have the largest influence on oyster recruitment and recruit health and this may be explained by environmental processes operating at the same scale. While survival was high across all estuaries, growth and reproduction of oysters on remnant reefs may be affected by sublethal effects on the health of recruits in high-sediment estuaries. Thus, restoration programs should consider lethal and sublethal effects of whole-estuary environmental processes when selecting sites and include environmental mitigation actions to maximize recruitment success.

2.
Artigo em Inglês | MEDLINE | ID: mdl-38578239

RESUMO

INTRODUCTION: Gender-affirming estrogen therapy (GAET) is commonly used for feminization in transgender and non-binary (TNB) individuals, yet the optimal rate of change (ROC) in estradiol levels for cardiovascular health is unclear. We examined the association between serum estradiol levels and cardiovascular-related mortality, adverse events, and risk factors in TNB adults using GAET. METHODS: Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE and Web of Science were systematically searched (inception-April 2023) for original articles reporting serum estradiol levels and cardiovascular-related mortality, adverse events, and risk factors in TNB adults using GAET. Data extraction was completed in duplicate following PRISMA guidelines. Stratified random effects meta-analyses using serum estradiol ROC (serum estradiolbaseline-serum estradiolfollow-up/study duration) was used to assess longitudinal studies (Low:0

3.
J Hist Neurosci ; : 1-11, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38598175

RESUMO

Walter Eichler (1904-1942) performed the first in situ nerve conduction studies in humans. Eichler's work has been largely overlooked and there have been no biographical accounts written of him. His 1937 paper, Über die Ableitung der Aktionspotentiale vom menschlichen Nerven in situ (On the recording of the action potentials from human nerves in situ) was translated and reviewed. Archival material was obtained on his career that was housed predominantly at the University of Freiburg im Breisgau. He had memberships in Nazi organizations but did not appear to be politically active. During his brief career, he constructed novel equipment and established seminal principles for performing nerve conductions on humans. The authors repeated his experiment in the ulnar nerve, which duplicated Eichler's findings. His recordings were quite remarkable given advances in technology. In summary, the Eichler paper is the first study in the development of in situ clinical electroneurography in humans. Many of his procedural observations are still fundamental in the current practice of electroneurography. As best can be determined, his study in humans did not appear ethically compromised. Although Eichler's personal background remains open to question, his paper is a seminal study in the history and development of clinical electroneurography.Abbreviations: AP: Action potential; C: Capacitor; CNP: Compound nerve potential; DC: Direct current; E1: Preferred term for active electrode; E2: Preferred term for reference electrode; NSDÄB: Nationalsozialistische Deutsche NSD-Ärtzebund (National Socialist German Doctors' League; NSDAP: Nationalsozialistische Deutsche Arbeiterpartei (National Socialist German Workers' Party/ Nazi Party); SS: Schutzstaffel (Protective Echelon or Squad of the Nazi party).

4.
Nat Commun ; 15(1): 2993, 2024 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-38582763

RESUMO

Bacteriophage therapy is a promising approach to address antimicrobial infections though questions remain regarding the impact of the immune response on clinical effectiveness. Here, we develop a mouse model to assess phage treatment using a cocktail of five phages from the Myoviridae and Siphoviridae families that target Vancomycin-Resistant Enterococcus gut colonization. Phage treatment significantly reduces fecal bacterial loads of Vancomycin-Resistant Enterococcus. We also characterize immune responses elicited following administration of the phage cocktail. While minimal innate responses are observed after phage administration, two rounds of treatment induces phage-specific neutralizing antibodies and accelerate phage clearance from tissues. Interestingly, the myophages in our cocktail induce a more robust neutralizing antibody response than the siphophages. This anti-phage immunity reduces the effectiveness of the phage cocktail in our murine model. Collectively, this study shows phage-specific immune responses may be an important consideration in the development of phage cocktails for therapeutic use.


Assuntos
Bacteriófagos , Enterococos Resistentes à Vancomicina , Humanos , Animais , Camundongos , Bacteriófagos/fisiologia , Vancomicina/farmacologia , Modelos Animais de Doenças , Myoviridae/fisiologia , Antibacterianos/farmacologia
5.
J Matern Fetal Neonatal Med ; 37(1): 2333923, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38584143

RESUMO

OBJECTIVE: To validate a serum biomarker developed in the USA for preterm birth (PTB) risk stratification in Viet Nam. METHODS: Women with singleton pregnancies (n = 5000) were recruited between 19+0-23+6 weeks' gestation at Tu Du Hospital, Ho Chi Minh City. Maternal serum was collected from 19+0-22+6 weeks' gestation and participants followed to neonatal discharge. Relative insulin-like growth factor binding protein 4 (IGFBP4) and sex hormone binding globulin (SHBG) abundances were measured by mass spectrometry and their ratio compared between PTB cases and term controls. Discrimination (area under the receiver operating characteristic curve, AUC) and calibration for PTB <37 and <34 weeks' gestation were tested, with model tuning using clinical factors. Measured outcomes included all PTBs (any birth ≤37 weeks' gestation) and spontaneous PTBs (birth ≤37 weeks' gestation with clinical signs of initiation of parturition). RESULTS: Complete data were available for 4984 (99.7%) individuals. The cohort PTB rate was 6.7% (n = 335). We observed an inverse association between the IGFBP4/SHBG ratio and gestational age at birth (p = 0.017; AUC 0.60 [95% CI, 0.53-0.68]). Including previous PTB (for multiparous women) or prior miscarriage (for primiparous women) improved performance (AUC 0.65 and 0.70, respectively, for PTB <37 and <34 weeks' gestation). Optimal performance (AUC 0.74) was seen within 19-20 weeks' gestation, for BMI >21 kg/m2 and age 20-35 years. CONCLUSION: We have validated a novel serum biomarker for PTB risk stratification in a very different setting to the original study. Further research is required to determine appropriate ratio thresholds based on the prevalence of risk factors and the availability of resources and preventative therapies.


Assuntos
Nascimento Prematuro , Gravidez , Recém-Nascido , Humanos , Feminino , Adulto Jovem , Adulto , Nascimento Prematuro/epidemiologia , Nascimento Prematuro/diagnóstico , Estudos de Coortes , 60515 , Prognóstico , Globulina de Ligação a Hormônio Sexual , Vietnã/epidemiologia , Idade Gestacional , Biomarcadores
6.
BMC Med Inform Decis Mak ; 24(Suppl 3): 103, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38641585

RESUMO

BACKGROUND: Alzheimer's Disease (AD) is a devastating disease that destroys memory and other cognitive functions. There has been an increasing research effort to prevent and treat AD. In the US, two major data sharing resources for AD research are the National Alzheimer's Coordinating Center (NACC) and the Alzheimer's Disease Neuroimaging Initiative (ADNI); Additionally, the National Institutes of Health (NIH) Common Data Elements (CDE) Repository has been developed to facilitate data sharing and improve the interoperability among data sets in various disease research areas. METHOD: To better understand how AD-related data elements in these resources are interoperable with each other, we leverage different representation models to map data elements from different resources: NACC to ADNI, NACC to NIH CDE, and ADNI to NIH CDE. We explore bag-of-words based and word embeddings based models (Word2Vec and BioWordVec) to perform the data element mappings in these resources. RESULTS: The data dictionaries downloaded on November 23, 2021 contain 1,195 data elements in NACC, 13,918 in ADNI, and 27,213 in NIH CDE Repository. Data element preprocessing reduced the numbers of NACC and ADNI data elements for mapping to 1,099 and 7,584 respectively. Manual evaluation of the mapping results showed that the bag-of-words based approach achieved the best precision, while the BioWordVec based approach attained the best recall. In total, the three approaches mapped 175 out of 1,099 (15.92%) NACC data elements to ADNI; 107 out of 1,099 (9.74%) NACC data elements to NIH CDE; and 171 out of 7,584 (2.25%) ADNI data elements to NIH CDE. CONCLUSIONS: The bag-of-words based and word embeddings based approaches showed promise in mapping AD-related data elements between different resources. Although the mapping approaches need further improvement, our result indicates that there is a critical need to standardize CDEs across these valuable AD research resources in order to maximize the discoveries regarding AD pathophysiology, diagnosis, and treatment that can be gleaned from them.


Assuntos
Doença de Alzheimer , Estados Unidos/epidemiologia , Humanos , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/epidemiologia , Elementos de Dados Comuns , Neuroimagem , National Institutes of Health (U.S.)
7.
Artigo em Inglês | MEDLINE | ID: mdl-38646842

RESUMO

BACKGROUND: Creatinine-based estimated glomerular filtration rate (eGFRCRE) may overestimate kidney function in patients with sarcopenia. While cystatin C-based eGFR (eGFRCYS) is less affected by muscle mass, it may underestimate kidney function in patients with obesity. We sought to evaluate the relationship between body composition defined by computed tomography (CT) scans and discordance between creatinine, eGFRCRE and eGFRCYS in adult patients with cancer. METHODS: This study is a cross-sectional study of consecutive adults with cancer with an abdominal CT scan performed within 90 days of simultaneous eGFRCRE and eGFRCYS measurements between May 2010 and January 2022. Muscle and adipose tissue cross-sectional areas were measured at the level of the third lumbar vertebral body using a validated deep-learning pipeline. CT-defined sarcopenia was defined using independent sex-specific cut-offs for skeletal muscle index (<39 cm2/m2 for women and <55 cm2/m2 for men). High adiposity was defined as the highest sex-specific quartile of the total (visceral plus subcutaneous) adiposity index in the cohort. The primary outcome was eGFR discordance, defined by eGFRCYS > 30% lower than eGFRCRE; the secondary outcome was eGFRCYS > 50% lower than eGFRCRE. The odds of eGFR discordance were estimated using multivariable logistic regression modelling. Unadjusted spline regression was used to evaluate the relationship between skeletal muscle index and the difference between eGFRCYS and eGFRCRE. RESULTS: Of the 545 included patients (mean age 63 ± 14 years, 300 [55%] females, 440 [80.7%] non-Hispanic white), 320 (58.7%) met the criteria for CT-defined sarcopenia, and 136 (25%) had high adiposity. A total of 259 patients (48%) had >30% eGFR discordance, and 122 (22.4%) had >50% eGFR discordance. After adjustment for potential confounders, CT-defined sarcopenia and high adiposity were both associated with >30% eGFR discordance (adjusted odds ratio [aOR] 1.90, 95% confidence interval [CI] 1.12-3.24; aOR 2.01, 95% CI 1.15-3.52, respectively) and >50% eGFR discordance (aOR 2.34, 95% CI 1.21-4.51; aOR 2.23, 95% CI 1.19-4.17, respectively). A spline model demonstrated that as skeletal muscle index decreases, the predicted difference between eGFRCRE and eGFRCYS widens considerably. CONCLUSIONS: CT-defined sarcopenia and high adiposity are both independently associated with large eGFR discordance. Incorporating valuable information from body composition analysis derived from CT scans performed as a part of routine cancer care can impact the interpretation of GFR estimates.

8.
Head Neck ; 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38622975

RESUMO

BACKGROUND: Neutrophilic cells are among the most abundant immune populations within the head and neck tumor microenvironment (TME) and harbor multiple mechanisms of immunosuppression. Despite these important features, neutrophilic cells may be underrepresented in contemporary studies that aim to comprehensively characterize the immune landscape of the TME due to discrepancies in tissue processing and analysis techniques. Here, we review the role of pathologically activated neutrophilic cells within the TME and pitfalls of various approaches used to study their frequency and function in clinical samples. METHODS: The literature was identified by searching PubMed for "immune landscape" and "tumor immune microenvironment" in combination with keywords describing solid tumor malignancies. Key publications that assessed the immune composition of solid tumors derived from human specimens were included. The tumor and blood processing methodologies in each study were reviewed in depth and correlated with the reported abundance of neutrophilic cells. RESULTS: Neutrophilic cells do not survive cryopreservation, and many studies fail to identify and study neutrophilic cell populations due to cryopreservation of clinical samples for practical reasons. Additional single-cell transcriptomic studies filter out neutrophilic cells due to low transcriptional counts. CONCLUSIONS: This report can help readers critically interpret studies aiming to comprehensively study the immune TME that fail to identify and characterize neutrophilic cells.

9.
Arch Pathol Lab Med ; 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38625026

RESUMO

CONTEXT.­: Rapid advancements in the understanding and manipulation of tumor-immune interactions have led to the approval of immune therapies for patients with non-small cell lung cancer. Certain immune checkpoint inhibitor therapies require the use of companion diagnostics, but methodologic variability has led to uncertainty around test selection and implementation in practice. OBJECTIVE.­: To develop evidence-based guideline recommendations for the testing of immunotherapy/immunomodulatory biomarkers, including programmed death ligand-1 (PD-L1) and tumor mutation burden (TMB), in patients with lung cancer. DESIGN.­: The College of American Pathologists convened a panel of experts in non-small cell lung cancer and biomarker testing to develop evidence-based recommendations in accordance with the standards for trustworthy clinical practice guidelines established by the National Academy of Medicine. A systematic literature review was conducted to address 8 key questions. Using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, recommendations were created from the available evidence, certainty of that evidence, and key judgments as defined in the GRADE Evidence to Decision framework. RESULTS.­: Six recommendation statements were developed. CONCLUSIONS.­: This guideline summarizes the current understanding and hurdles associated with the use of PD-L1 expression and TMB testing for immune checkpoint inhibitor therapy selection in patients with advanced non-small cell lung cancer and presents evidence-based recommendations for PD-L1 and TMB testing in the clinical setting.

10.
CNS Drugs ; 38(5): 333-347, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38587586

RESUMO

Parkinson's disease (PD) is associated with the development of psychosis (PDP), including hallucinations and delusions, in more than half of the patient population. Optimal PD management must therefore involve considerations about both motor and non-motor symptoms. Often, clinicians fail to diagnosis psychosis in patients with PD and, when it is recognized, treat it suboptimally, despite the availability of multiple interventions. In this paper, we provide a summary of the current guidelines and clinical evidence for treating PDP with antipsychotics. We also provide recommendations for diagnosis and follow-up. Finally, an updated treatment algorithm for PDP that incorporates the use of pimavanserin, the only US FDA-approved drug for the treatment of PDP, was developed by extrapolating from a limited evidence base to bridge to clinical practice using expert opinion and experience. Because pimavanserin is only approved for the treatment of PDP in the US, in other parts of the world other recommendations and algorithms must be considered.


Assuntos
Antipsicóticos , Doença de Parkinson , Transtornos Psicóticos , Ureia/análogos & derivados , Humanos , Doença de Parkinson/complicações , Doença de Parkinson/tratamento farmacológico , Transtornos Psicóticos/tratamento farmacológico , Transtornos Psicóticos/etiologia , Alucinações/complicações , Alucinações/tratamento farmacológico , Piperidinas/uso terapêutico , Antipsicóticos/uso terapêutico
11.
JCO Precis Oncol ; 8: e2300687, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38635935

RESUMO

Radiomics, the science of extracting quantifiable data from routine medical images, is a powerful tool that has many potential applications in oncology. The Response Evaluation Criteria in Solid Tumors Working Group (RWG) held a workshop in May 2022, which brought together various stakeholders to discuss the potential role of radiomics in oncology drug development and clinical trials, particularly with respect to response assessment. This article summarizes the results of that workshop, reviewing radiomics for the practicing oncologist and highlighting the work that needs to be done to move forward the incorporation of radiomics into clinical trials.


Assuntos
Neoplasias , Medicina de Precisão , Humanos , Medicina de Precisão/métodos , Critérios de Avaliação de Resposta em Tumores Sólidos , 60570 , Oncologia , Neoplasias/diagnóstico por imagem , Neoplasias/tratamento farmacológico
13.
J Phys Chem A ; 128(15): 3015-3023, 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38593044

RESUMO

Respiratory viruses, such as influenza and severe acute respiratory syndrome coronavirus 2, represent a substantial public health burden and are largely transmitted through respiratory droplets and aerosols. Environmental factors such as relative humidity (RH) and temperature impact virus transmission rates, and a precise mechanistic understanding of the connection between these environmental factors and virus transmission would improve efforts to mitigate respiratory disease transmission. Previous studies on supermicrometer particles observed RH-dependent phase transitions and linked particle phase state to virus viability. Phase transitions in atmospheric aerosols are dependent on size in the submicrometer range, and actual respiratory particles are expelled over a large size range, including submicrometer aerosols that can transmit diseases over long distances. Here, we directly investigated the phase transitions of submicrometer model respiratory aerosols. A probe molecule, Nile red, was added to particle systems including multiple mucin/salt mixtures, a growth medium, and simulated lung fluid. For each system, the polarity-dependent fluorescence emission was measured following RH conditioning. Notably, the fluorescence measurements of mucin/NaCl and Dulbecco's modified Eagle's medium particles indicated that liquid-liquid phase separation (LLPS) also occurs in submicron particles, suggesting that LLPS can also impact the viability of viruses in submicron particles and thus affect aerosol virus transmission. Furthermore, the utility of fluorescence-based measurements to study submicrometer respiratory particle physicochemical properties in situ is demonstrated.


Assuntos
Mucinas , Aerossóis e Gotículas Respiratórios , Umidade , Aerossóis/química
14.
J Med Chem ; 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38635563

RESUMO

Cofactor mimicry represents an attractive strategy for the development of enzyme inhibitors but can lead to off-target effects due to the evolutionary conservation of binding sites across the proteome. Here, we uncover the ADP-ribose (ADPr) hydrolase NUDT5 as an unexpected, noncovalent, off-target of clinical BTK inhibitors. Using a combination of biochemical, biophysical, and intact cell NanoBRET assays as well as X-ray crystallography, we confirm catalytic inhibition and cellular target engagement of NUDT5 and reveal an unusual binding mode that is independent of the reactive acrylamide warhead. Further investigation of the prototypical BTK inhibitor ibrutinib also revealed potent inhibition of the largely unstudied NUDIX hydrolase family member NUDT14. By exploring structure-activity relationships (SARs) around the core scaffold, we identify a potent, noncovalent, and cell-active dual NUDT5/14 inhibitor. Cocrystallization experiments yielded new insights into the NUDT14 hydrolase active site architecture and inhibitor binding, thus providing a basis for future chemical probe design.

15.
Contemp Clin Trials ; 141: 107534, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38614447

RESUMO

BACKGROUND: Leveraging military veterans' intimate relationships during treatment has the potential to concurrently improve posttraumatic stress disorder (PTSD) symptoms and relationship quality. Cognitive-Behavioral Conjoint Therapy (CBCT) and an 8-session Brief Cognitive-Behavioral Conjoint Therapy (bCBCT) are manualized treatments designed to simultaneously improve PTSD and relationship functioning for couples in which one partner has PTSD. Although efficacious in improving PTSD, the effects of CBCT on relationship satisfaction are small, especially among veterans. Intranasal oxytocin, which targets mechanisms of PTSD and relationship quality, may enhance the efficacy of bCBCT. METHOD/DESIGN: The purpose of this 4-year clinical trial is to compare the outcomes of bCBCT augmented with intranasal oxytocin versus bCBCT plus placebo. We will also explore potential mechanisms of action: self-reported communication skills, empathy, and trust. We will recruit 120 dyads (i.e., veteran with PTSD and their intimate partner) from the VA San Diego Healthcare System. Veterans will be administered 40 international units of oxytocin (n = 60) or placebo (n = 60) 30 min before each of 8 bCBCT sessions delivered via telehealth. Clinical and functioning outcomes will be assessed at five timepoints (baseline, mid-treatment, post-treatment, and 3- and 6-month follow-up). CONCLUSION: Study findings will reveal the efficacy of oxytocin-assisted brief couple therapy for PTSD, which could serve as highly scalable option for couples coping with PTSD, as well as provide preliminary evidence of interpersonal mechanisms of change. CLINICALTRIALS: govIdentifier:NCT06194851.

16.
Clin Colon Rectal Surg ; 37(3): 191-197, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38617844

RESUMO

Familial adenomatous polyposis (FAP) is an autosomal dominant disorder affecting patients with germline mutations of the adenomatous polyposis coli (APC) tumor suppressor gene. The surgical treatment of colorectal disease in FAP, which has the goal of colorectal cancer prevention, varies based on both patient and disease factors but can include the following: total colectomy with ileorectal anastomosis, proctocolectomy with stapled or hand-sewn ileal pouch-anal anastomosis, or total proctocolectomy with end ileostomy. The operative options and extent of resection, as well as the use of endoscopy and chemoprevention for the management of polyposis, will be discussed in detail in this article. In addition, commonly debated management decisions related to the treatment of patients with FAP, including the timing of prophylactic colorectal resections for patients with FAP and management of the polyp burden in the rectum, will be discussed. Finally, genotype considerations and the impact of desmoid disease on operative decisions in the setting of FAP will also be reviewed.

17.
JBJS Rev ; 12(4)2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38619382

RESUMO

¼ Posterior glenohumeral instability is relatively uncommon compared with anterior instability, but is becoming an increasingly recognized and surgically managed shoulder pathology.¼ Soft-tissue stabilization alone may not be sufficient in patients who present with substantial bone loss to the posterior glenoid and/or the anterior humeral head.¼ For posterior glenoid defects, posterior glenoid osteoarticular augmentation can be used, and posterior glenoid opening wedge osteotomy can be considered in cases of posterior instability with pathologic retroversion.¼ For humeral head lesions, several surgical treatment options are available including subscapularis transposition into the humeral head defect, autograft or allograft reconstruction, humeral rotation osteotomy, and shoulder arthroplasty.


Assuntos
Instabilidade Articular , Articulação do Ombro , Humanos , Ombro , Instabilidade Articular/cirurgia , Articulação do Ombro/cirurgia , Escápula , Cabeça do Úmero/cirurgia
18.
Brain Stimul ; 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38604563

RESUMO

Non-invasive brain stimulation techniques, such as transcranial direct current stimulation (tDCS), are popular methods for inducing neuroplastic changes to alter cognition and behaviour. One challenge for the field is to optimise stimulation protocols to maximise benefits. For this to happen, we need a better understanding of how stimulation modulates cortical functioning/behaviour. To date, there is increasing evidence for a dose-response relationship between tDCS and brain excitability, however how this relates to behaviour is not well understood. Even less is known about the neurochemical mechanisms which may drive the dose-response relationship between stimulation intensities and behaviour. Here, we examine the effect of three different tDCS stimulation intensities (1 mA, 2 mA, 4 mA anodal motor cortex tDCS) administered during the explicit learning of motor sequences. Further, to assess the role of dopamine in the dose-response relationship between tDCS intensities and behaviour, we examined how pharmacologically increasing dopamine availability, via 100 mg of levodopa, modulated the effect of stimulation on learning. In the absence of levodopa, we found that 4 mA tDCS improved and 1 mA tDCS impaired acquisition of motor sequences relative to sham stimulation. Conversely, levodopa reversed the beneficial effect of 4 mA tDCS. This effect of levodopa was no longer evident at the 48-h follow-up, consistent with previous work characterising the persistence of neuroplastic changes in the motor cortex resulting from combining levodopa with tDCS. These results provide the first direct evidence for a role of dopamine in the intensity-dependent effects of tDCS on behaviour.

19.
J Biol Chem ; : 107282, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38604564

RESUMO

The major human pathogen Streptococcus pneumoniae encounters the immune-derived oxidant hypothiocyanous acid (HOSCN) at sites of colonization and infection. We recently identified the pneumococcal hypothiocyanous acid reductase (Har), a member of the flavoprotein disulfide reductase enzyme family, and showed that it contributes to the HOSCN tolerance of S. pneumoniae in vitro. Here, we demonstrate in mouse models of pneumococcal infection that Har is critical for colonization and invasion. In a colonization model, bacterial load was attenuated dramatically in the nasopharynx when har was deleted in S. pneumoniae. The Δhar strain was also less virulent compared to wild type in an invasion model as reflected by a significant reduction in bacteria in the lungs and no dissemination to the blood and brain. Kinetic measurements with recombinant Har demonstrated that this enzyme reduced HOSCN with near diffusion limited catalytic efficiency, using either NADH (kcat/KM = 1.2 x 108 M-1s-1) or NADPH (kcat/KM = 2.5 x 107 M-1s-1) as electron donors. We determined the X-ray crystal structure of Har in complex with the FAD cofactor to 1.50 Å resolution, highlighting the active site architecture characteristic for this class of enzymes. Collectively, our results demonstrate that pneumococcal Har is a highly efficient HOSCN reductase, enabling survival against oxidative host immune defenses. In addition, we provide structural insights that may aid the design of Har inhibitors.

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