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1.
Function (Oxf) ; 2024 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-39289003

RESUMO

The regulation of vascular tone by perivascular tissues is a complex interplay of various paracrine factors. Here, we investigate the anti-contractile effect of skeletal muscle surrounding the femoral and carotid arteries and its underlying mechanisms. Using male and female Wistar rats, we demonstrated that serotonin, phenylephrine, and U-46619 induced a concentration-dependent vasoconstrictor response in femoral artery rings. Interestingly, this response was diminished in the presence of surrounding femoral skeletal muscle, irrespective of sex. No anti-contractile effect was observed when the carotid artery was exposed to its surrounding skeletal muscle. The observed effect in the femoral artery persisted even in the absence of endothelium and when the muscle was detached from the artery. Furthermore, the skeletal muscle surrounding the femoral artery was able to promote an anti-contractile effect in three other vascular beds (basilar, mesenteric, and carotid arteries). Using inhibitors of lactate dehydrogenase and the 1/4 monocarboxylate transporter, we confirmed the involvement of lactate, as both inhibitors were able to abolish the anti-contractile effect. However, lactate did not directly promote vasodilation; rather, it exerted its effect by activating 5' AMP-activated protein kinase (AMPK) and neuronal nitric oxide synthase (NOS1) in the skeletal muscle. Accordingly, Nω-propyl L-arginine, a specific inhibitor of NOS1, prevented the anti-contractile effect, as well as lactate-induced phosphorylation of NOS1 at the stimulatory serine site (1417) in primary skeletal muscle cells. Phosphorylation of NOS1 was reduced in the presence of Bay-3827, a selective AMPK inhibitor. In conclusion, femoral artery-associated skeletal muscle is a potent paracrine and endocrine organ that influences vascular tone in both sexes. Mechanistically, the anti-contractile effect involves muscle fiber type and/or its anatomical location but not the type of artery or its related vascular endothelium. Finally, the femoral artery anti-contractile effect is mediated by the lactate-AMPK-phospho-NOS1Ser1417-NO signaling axis.

2.
N Am Spine Soc J ; 19: 100517, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39205670

RESUMO

Background: Spinal deformity as a sequela of nontuberculous spondylodiscitis is a rarely discussed clinical entity. Sagittal plane deformity, segmental instability, and persistently active infection overlap in these patients resulting in severe restriction in activity and quality of life. The presence of multiple medical co-morbidities restricts surgical options but nonoperative care may be ineffective and result in persistent, refractory discitis for years. We describe our experience with vertebrectomy and long-segment fixation for patients with postinfectious thoracic or lumbar deformity. Methods: A retrospective chart review of 23 consecutive patients who underwent vertebrectomy and long-segment fixation for thoracic or lumbar deformity secondary to nontuberculous bacterial spondylodiscitis was performed. Pre, peri- and postoperative data is compiled and analyzed with a focus on the perioperative management algorithm to safely perform an extensive reconstruction in this very sick patient population. Results: Extremely low preoperative quality of life was evident with 87% (20/23) of patients bedridden primarily due to pain despite 70% (16/23) of patients being strong enough to ambulate (Frankel D or E). Most patients (87%) already had an identified infection under adequate treatment either through blood cultures, prior biopsy or decompressive surgery. A single-stage posterior-only was the primary surgical approach utilized in the majority (83%) of cases. Complications were present in 100% of patients, most commonly perioperative anemia and hypotension requiring vasopressor support and aggressive blood product replacement. One in-hospital mortality occurred secondarily to pulmonary embolism. Mean preoperative segmental angle was 18±10 degrees of kyphosis which was corrected to 1±9 degrees of lordosis (p=.001). The mean correction of the segmental angle was 19 degrees (standard deviation 23 degrees). Visual analogue scale scores improved from a preoperative value of 8.8±0.9 to a postoperative value of 2.5±1.4 (p<.001), which was obtained at the last outpatient follow-up (mean 631 days after surgery). Full self-care including ambulation was achieved in 18/23 (78%) patients, and the infection was successfully treated in 22/23 (96%) patients after long-term antibiotics. Conclusions: Patients with refractory spondylodiscitis on appropriate care and antibiotics are typically considered extremely poor surgical candidates despite nonoperative care often being ineffective. Postinfectious deformity may also be so severe as to preclude a limited surgical treatment strategy. This study suggests that extensive circumferential reconstruction for deformity secondary to bacterial spondylodiscitis can be effective in restoring these extremely sick patients to self-care and ambulatory status.

3.
Arthroplast Today ; 27: 101427, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38966328

RESUMO

Femoral nerve injury is a rare but devastating complication of direct anterior approach total hip arthroplasty that occurs in about 1% of the cases and could potentially lead to debilitating loss of knee extension. In this case report, we present a case of femoral nerve injury following direct anterior approach hip arthroplasty with an inability to extend the affected knee, gait instability, and multiple falls. For this patient, an innovative functional adductor magnus muscle transfer was performed to restore knee extension. At 6 months after surgery, the patient's knee extension was partly restored, and ambulation was significantly improved.

4.
World Neurosurg ; 2024 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-38992727

RESUMO

OBJECTIVE: This study evaluates the impact of L4-L5 minimally invasive surgery (MIS)- transforaminal lumbar interbody fusion (TLIF) on adjacent-level parameters. METHODS: This is a retrospective study performed on consecutive patients between January 2015 and December 2019. The index- and adjacent-level segmental lordosis (SL) and disc angle (DA) were measured. Patient-reported outcomes (PROs) were collected preoperatively and at 3-24 months postoperatively. Factors influencing changes in adjacent-level parameters and the occurrence of adjacent segment degeneration (ASDeg) were assessed. RESULTS: A total of 117 adult patients, averaging 65.5 years of age and slight preponderance of female (56.4%), were analyzed. L4-L5 SL decreased at 2 years (P < 0.05), but L4-L5 DA significantly increased at all timepoints (P < 0.05). While L3-L4 SL and DA significantly decreased at all timepoints (P < 0.05), L5-S1 SL decreased at 3 and 12 months (P < 0.05) and L5-S1 DA only significantly decreased at 2 years (P < 0.05). All PROs improved significantly (P < 0.0001). The ASDeg rate was 19.7% at 2.2 years. Cephalad and caudal ASDeg rates were 12.0% and 10.3%, respectively. Eight patients (6.8%) required adjacent-level reoperations, mainly at L3-L4 (6 cases). The use of expandable cage significantly reduced the odds of caudal ASDeg (OR 0.15, P = 0.037), but had no significant effect on cephalad ASDeg. CONCLUSIONS: L4-L5 MIS-TLIF had a more consistent effect on L3-L4 than L5-S1. Although adjacent-level SL and DA decreased over time, their association with ASDeg appears limited, suggesting a multifactorial etiology. L4-L5 MIS-TLIF provides demonstrable clinical benefits with lasting PRO improvements and low adjacent-level reoperations.

5.
Mar Drugs ; 22(6)2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38921579

RESUMO

Bioprospecting the secondary metabolism of underexplored Actinomycetota taxa is a prolific route to uncover novel chemistry. In this work, we report the isolation, structure elucidation, and bioactivity screening of cellulamides A and B (1 and 2), two novel linear peptides obtained from the culture of the macroalga-associated Cellulosimicrobium funkei CT-R177. The host of this microorganism, the Chlorophyta Codium tomentosum, was collected in the northern Portuguese coast and, in the scope of a bioprospecting study focused on its associated actinobacterial community, strain CT-R177 was isolated, taxonomically identified, and screened for the production of antimicrobial and anticancer compounds. Dereplication of a crude extract of this strain using LC-HRMS(/MS) analysis unveiled a putative novel natural product, cellulamide A (1), that was isolated following mass spectrometry-guided fractionation. An additional analog, cellulamide B (2) was obtained during the chromatographic process and chemically characterized. The chemical structures of the novel linear peptides, including their absolute configurations, were elucidated using a combination of HRMS, 1D/2D NMR spectroscopy, and Marfey's analysis. Cellulamide A (1) was subjected to a set of bioactivity screenings, but no significant biological activity was observed. The cellulamides represent the first family of natural products reported from the Actinomycetota genus Cellulosimicrobium, showcasing not only the potential of less-explored taxa but also of host-associated marine strains for novel chemistry discovery.


Assuntos
Peptídeos , Humanos , Peptídeos/química , Peptídeos/farmacologia , Peptídeos/isolamento & purificação , Actinobacteria/química , Actinobacteria/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Organismos Aquáticos , Produtos Biológicos/farmacologia , Produtos Biológicos/química , Produtos Biológicos/isolamento & purificação , Linhagem Celular Tumoral , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/isolamento & purificação
6.
Artigo em Inglês | MEDLINE | ID: mdl-38791794

RESUMO

BACKGROUND: Adopting advanced digital technologies as diagnostic support tools in healthcare is an unquestionable trend accelerated by the COVID-19 pandemic. However, their accuracy in suggesting diagnoses remains controversial and needs to be explored. We aimed to evaluate and compare the diagnostic accuracy of two free accessible internet search tools: Google and ChatGPT 3.5. METHODS: To assess the effectiveness of both medical platforms, we conducted evaluations using a sample of 60 clinical cases related to urological pathologies. We organized the urological cases into two distinct categories for our analysis: (i) prevalent conditions, which were compiled using the most common symptoms, as outlined by EAU and UpToDate guidelines, and (ii) unusual disorders, identified through case reports published in the 'Urology Case Reports' journal from 2022 to 2023. The outcomes were meticulously classified into three categories to determine the accuracy of each platform: "correct diagnosis", "likely differential diagnosis", and "incorrect diagnosis". A group of experts evaluated the responses blindly and randomly. RESULTS: For commonly encountered urological conditions, Google's accuracy was 53.3%, with an additional 23.3% of its results falling within a plausible range of differential diagnoses, and the remaining outcomes were incorrect. ChatGPT 3.5 outperformed Google with an accuracy of 86.6%, provided a likely differential diagnosis in 13.3% of cases, and made no unsuitable diagnosis. In evaluating unusual disorders, Google failed to deliver any correct diagnoses but proposed a likely differential diagnosis in 20% of cases. ChatGPT 3.5 identified the proper diagnosis in 16.6% of rare cases and offered a reasonable differential diagnosis in half of the cases. CONCLUSION: ChatGPT 3.5 demonstrated higher diagnostic accuracy than Google in both contexts. The platform showed satisfactory accuracy when diagnosing common cases, yet its performance in identifying rare conditions remains limited.


Assuntos
Ferramenta de Busca , Humanos , COVID-19/diagnóstico , Internet , Doenças Urológicas/diagnóstico , SARS-CoV-2 , Diagnóstico Diferencial
7.
An Acad Bras Cienc ; 96(1): e20230532, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38597491

RESUMO

In this work, evaluated the antifungal chemosensitizing effect of the Lippia origanoides essential oil (EO) through the induction of oxidative stress. The EO was obtained by hydrodistillation and analyzed by GC-MS. To evaluate the antifungal chemosensitizing effect through induction of oxidative stress, cultures of the model yeast Saccharomyces cerevisiae ∆ycf1 were exposed to sub-inhibitory concentrations of the EO, and the expression of genes known, due be overexpressed in response to oxidative and mutagenic stress was analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) method. Carvacrol and thymol were identified as the main components. The EO was effective in preventing or reducing the growth of the microorganisms tested. The gene expression profiles showed that EO promoted changes in the patterns of expression of genes involved in oxidative and mutagenic stress resistance. The combined use of the L. origanoides EO with fluconazole has been tested on Candida yeasts and the strategy resulted in a synergistic enhancement of the antifungal action of the azolic chemical product. Indeed, in association with EO, the fluconazole MICs dropped. Thus, the combinatorial use of L. origanoides EO as a chemosensitizer agent should contribute to enhancing the efficiency of conventional antifungal drugs, reducing their negative side effects.


Assuntos
Candidíase , Lippia , Óleos Voláteis , Antifúngicos/farmacologia , Óleos Voláteis/farmacologia , Óleos Voláteis/química , Lippia/química , Fluconazol/farmacologia , Estresse Oxidativo
8.
World Neurosurg ; 186: e577-e583, 2024 06.
Artigo em Inglês | MEDLINE | ID: mdl-38588790

RESUMO

BACKGROUND AND OBJECTIVES: Studies have demonstrated increased risk of adjacent segment disease (ASD) after open fusion with adjacent-level laminectomy, with rates ranging from 16%-47%, potentially related to disruption of the posterior ligamentous complex. Minimally invasive surgical (MIS) approaches may offer a more durable result. We report institutional outcomes of simultaneous MIS transforaminal lumbar interbody fusion (MISTLIF) and adjacent-level laminectomy for patients with low grade spondylolisthesis and ASD. METHODS: Retrospective analysis was performed on patients who underwent MISTLIF with adjacent level laminectomy to treat grade I-II spondylolisthesis with adjacent stenosis at a single institution from 2007-2022. RESULTS: A total of 34 patients met criteria, with mean follow-up of 23.1 months. In total, 37 levels were fused and 45 laminectomies performed. In this group, 21 patients received a single level laminectomy and single-level MISTLIF, 10 patients received a 2-level laminectomy and single-level MISTLIF, 2 patients received a single-level laminectomy and 2-level MISTLIF, and 1 patient received a 2-level laminectomy and 2-level MISTLIF. Three (8.8%) patients experienced clinically significant postoperative ASD requiring reoperation. Three other patients required reoperation for other reasons. Multiple logistic regression did not reveal any association between development of ASD and surgical covariates. CONCLUSION: MISTLIF with adjacent-level laminectomy demonstrated a favorable safety profile with rates of postoperative ASD lower than published rates after open fusion and on par with the published rates of ASD from MISTLIF alone. Future prospective studies may better elucidate the durability of adjacent-level laminectomies when performed alongside MISTLIF, but retrospective data suggests it is safe and durable.


Assuntos
Laminectomia , Vértebras Lombares , Procedimentos Cirúrgicos Minimamente Invasivos , Complicações Pós-Operatórias , Fusão Vertebral , Estenose Espinal , Espondilolistese , Humanos , Espondilolistese/cirurgia , Laminectomia/métodos , Fusão Vertebral/métodos , Fusão Vertebral/efeitos adversos , Feminino , Masculino , Estenose Espinal/cirurgia , Pessoa de Meia-Idade , Vértebras Lombares/cirurgia , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Estudos Retrospectivos , Idoso , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Adulto , Resultado do Tratamento
9.
Parasite Immunol ; 46(2): e13028, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38389494

RESUMO

Canine visceral leishmaniasis is a parasitic zoonosis that has a profound impact on public health in countries where it is endemic. Chemotherapeutic treatments cannot keep dogs stable for long periods, and the risk of generating parasitic resistance must be considered. Forty-four symptomatic and naturally infected dogs with Leishmania infantum were tested with two treatment protocols (i) immunotherapy with LaSap vaccine and (ii) immunochemotherapy with LaSap vaccine plus allopurinol. At 90 days after the end of the treatment, it was verified that, although both protocols had generated significant clinical improvements with a greater production of IFN-γ/IL-10, in relation to the parasite load, mainly in the skin, the dogs treated only with immunotherapy maintained the same profile. These results indicate that LaSap is a good strategy to control dog parasitism.


Assuntos
Doenças do Cão , Leishmania infantum , Leishmaniose Visceral , Vacinas , Animais , Cães , Alopurinol/uso terapêutico , Leishmaniose Visceral/tratamento farmacológico , Leishmaniose Visceral/prevenção & controle , Leishmaniose Visceral/veterinária , Imunoterapia/métodos , Doenças do Cão/tratamento farmacológico , Doenças do Cão/prevenção & controle
10.
PLoS Genet ; 20(1): e1011126, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38252672

RESUMO

Dobzhansky and Muller proposed a general mechanism through which microevolution, the substitution of alleles within populations, can cause the evolution of reproductive isolation between populations and, therefore, macroevolution. As allopatric populations diverge, many combinations of alleles differing between them have not been tested by natural selection and may thus be incompatible. Such genetic incompatibilities often cause low fitness in hybrids between species. Furthermore, the number of incompatibilities grows with the genetic distance between diverging populations. However, what determines the rate and pattern of accumulation of incompatibilities remains unclear. We investigate this question by simulating evolution on holey fitness landscapes on which genetic incompatibilities can be identified unambiguously. We find that genetic incompatibilities accumulate more slowly among genetically robust populations and identify two determinants of the accumulation rate: recombination rate and population size. In large populations with abundant genetic variation, recombination selects for increased genetic robustness and, consequently, incompatibilities accumulate more slowly. In small populations, genetic drift interferes with this process and promotes the accumulation of genetic incompatibilities. Our results suggest a novel mechanism by which genetic drift promotes and recombination hinders speciation.


Assuntos
Evolução Biológica , Especiação Genética , Modelos Genéticos , Deriva Genética , Recombinação Genética , Hibridização Genética
11.
Phys Chem Chem Phys ; 26(4): 3101-3109, 2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38180484

RESUMO

Vibrational spectra of a series of gas-phase metal 1+ and 2+ ions solvated by acetone molecules are collected to investigate how the metal charge, number of solvent molecules and nature of the metal affect the acetone. The spectra of Cu+(Ace)(N2)2, Cu+(Ace)4, and M2+(Ace)4, where M = Co, Ni, Cu, and Zn are measured via photodissociation by monitoring fragment ion signal as a function of IR wavenumber. The spectra show a red shift of the CO stretch and a blue shift of the C-C antisymmetric stretch. DFT calculations are carried out to provide the simulated spectra of possible isomers to be compared with the observed vibrational spectra, and specific structures are proposed. The red shift of the CO stretch increases as the number of acetone molecules decreases. Higher charge on the metal leads to a larger red shift in the CO stretch. Although all of the M2+ complexes have very similar red shifts, they are predicted to have different geometries due to their different electron configurations. Unexpectedly, we find that the calculated red shift in the CO stretch in M+/2+(Ace) is highly linearly correlated with the ionization energy of the metal for a wide range of metal cations and dications.

12.
Neurosurgery ; 94(2): 350-357, 2024 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-37706880

RESUMO

BACKGROUND AND OBJECTIVES: In 2013, all neurosurgery programs were mandated to adopt a 7-year structure. We sought to characterize how programs use the seventh year of training (postgraduate year 7 [PGY7]). METHODS: We surveyed all accredited neurosurgery programs in the United States regarding the PGY7 residents' primary role and the availability of enfolded fellowships. We compiled responses from different individuals in each program: chair, program director, program coordinator, and current chiefs. RESULTS: Of 120 accredited neurological surgery residency programs within the United States, 91 (76%) submitted responses. At these programs, the primary roles of the PGY7 were chief of service (COS, 71%), enfolded fellowships (EFF, 18%), transition to practice (10%), and elective time (1%). Most residencies have been 7-year programs for >10 years (52, 57%). Sixty-seven programs stated that they offer some form of EFF (73.6%). The most common EFFs were endovascular (57, 62.6%), spine (49, 53.9%), critical care (41, 45.1%), and functional (37, 40.7%). These were also the most common specialties listed as Committee on Advanced Subspecialty Training accredited by survey respondents. Spine and endovascular EFFs were most likely to be restricted to PGY7 (24.2% and 23.1%, respectively), followed by neuro-oncology (12, 13.2%). The most common EFFs reported as Committee on Advanced Subspecialty Training accredited but not restricted to PGY7 were endovascular (24, 26.4%) and critical care (23, 25.3%). CONCLUSION: Most accredited neurological surgery training programs use the COS as the primary PGY7 role. Programs younger in their PGY7 structure seem to maintain the traditional COS role. Those more established seem to be experimenting with various roles the PGY7 year can fill, including enfolded fellowships and transition-to-practice years, predominantly. Most programs offer some form of enfolded fellowship. This serves as a basis for characterization of how neurological surgery training may develop in years to come.


Assuntos
Internato e Residência , Neurocirurgia , Humanos , Estados Unidos , Educação de Pós-Graduação em Medicina , Currículo , Neurocirurgia/educação , Bolsas de Estudo
13.
J Neurosurg Spine ; 40(2): 216-228, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-37976498

RESUMO

OBJECTIVE: Postoperative C5 palsy (C5P) is a known complication in cervical spine surgery. However, its exact pathophysiology is unclear. The authors aimed to provide a review of the current understanding of C5P by performing a comprehensive, systematic review of the existing literature and conducting a critical appraisal of existing evidence to determine the risk factors of C5P. METHODS: A systematic search of PubMed/MEDLINE (January 1, 2019, to July 2, 2021), EMBASE (inception to July 2, 2021), and Cochrane (inception to July 2, 2021) databases was conducted. Preestablished criteria were used to evaluate studies for inclusion. Studies that adjusted for one or more of the following factors were considered: preoperative foraminal diameter (FD) at C4/5, posterior spinal cord shift at C4/5, preoperative anterior-posterior diameter (APD) at C4/5, preoperative spinal cord rotation, and change in C2-7 Cobb angle. Studies were rated as good, fair, or poor based on the Quality in Prognosis Studies (QUIPS) tool. Random effects meta-analyses were done using methods outlined by Cochrane methodologists for pooling of prognostic studies. Overall quality (strength) of evidence was based on Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methods for prognostic studies. The protocol for this review was published on the PROSPERO (CRD264358) website. RESULTS: Of 303 potentially relevant citations of studies, 12 met the inclusion criteria set a priori. These works provide moderate-quality evidence that preoperative FD substantially increases the odds of C5P in patients undergoing posterior cervical surgery. Pooled estimates across 7 studies in which various surgical approaches were used indicate that the odds of C5P approximately triple for each millimeter decrease in preoperative FD (OR 3.05, 95% CI 2.07-4.49). Preoperative APD increases the odds of C5P, but the confidence is low. Across 3 studies, each using different surgical approaches, each millimeter decrease in preoperative APD was associated with a more than 2-fold increased odds of C5P (pooled OR 2.51, 95% CI 1.69-3.73). Confidence that there is an association with postoperative C5P and posterior spinal cord shift, change in sagittal Cobb angle, and preoperative spinal cord rotation is very low. CONCLUSIONS: The exact pathophysiological process resulting in postoperative C5P remains an enigma but there is a clear association with foraminal stenosis, especially when performing posterior procedures. C5P is also related to decreased APD but the association is less clear. The overall quality (strength) of evidence provided by the current literature is low to very low for most factors. Systematic review registration no.: CRD264358 (https://www.crd.york.ac.uk/prospero/).


Assuntos
Paralisia , Medula Espinal , Humanos , Paralisia/cirurgia , Medula Espinal/cirurgia , Fatores de Risco , Prognóstico , Vértebras Cervicais/cirurgia , Análise Multivariada , Descompressão Cirúrgica/métodos
15.
An Acad Bras Cienc ; 95(suppl 3): e20220591, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37937657

RESUMO

This study investigated the spatial patterns of atmospheric circulation associated with surface air temperature variability trends between the Antarctic Peninsula and South America, during the austral summer (1979-2020). The first mode shows a positive score trend, with warming in northern Antarctic Peninsula and southern South America. This mode is mainly associated with the positive/neutral Southern Annular Mode and La Niña phases. There is an anomalous low pressure in the Southeast Pacific, a strengthening (weakening) of the polar (subtropical) jet and a strengthening and/or south/southwest displacement of the South Atlantic Subtropical High, which can prevent the passage of transient systems over the continent. In addition, there is a negative phase pattern of the South Atlantic Dipole, which contributes to the strengthening of the South Atlantic Convergence Zone convective activity. The second mode shows a negative score trend, with cooling in the Antarctic Peninsula/southernmost South America and warming between 10-40°S over South America. This mode is mainly associated with the spatial pattern of Central Pacific El Niño. There is a strengthening of the low-level jet and a strengthening of the western branch of the South Atlantic Subtropical High, all of which contribute to the suppression of the South Atlantic Convergence Zone.


Assuntos
Temperatura Baixa , Temperatura , Regiões Antárticas , Estações do Ano , América do Sul
16.
J Math Biol ; 87(6): 88, 2023 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-37994999

RESUMO

Asexual populations are expected to accumulate deleterious mutations through a process known as Muller's ratchet. Lynch and colleagues proposed that the ratchet eventually results in a vicious cycle of mutation accumulation and population decline that drives populations to extinction. They called this phenomenon mutational meltdown. Here, we analyze mutational meltdown using a multi-type branching process model where, in the presence of mutation, populations are doomed to extinction. We analyse the change in size and composition of the population and the time of extinction under this model.


Assuntos
Genética Populacional , Modelos Genéticos , Mutação , Reprodução Assexuada
17.
J Chem Phys ; 159(17)2023 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-37916597

RESUMO

Photofragment spectroscopy is used to measure the vibrational spectra of V2+(CH4)n (n = 1-4), V3+(CH4)n (n = 1-3), and Vx+(CH4) (x = 4-8) in the C-H stretching region (2550-3100 cm-1). Spectra are measured by monitoring loss of CH4. The experimental spectra are compared to simulations at the B3LYP+D3/6-311++G(3df,3pd) level of theory to identify the geometry of the ions. Multi-reference configuration interaction with Davidson correction (MRCI+Q) calculations are also carried out on V2+ and V3+. The methane binding orientation in V2+(CH4)n (n = 1-4) evolves from η3 to η2 as more methane molecules are added. The IR spectra of metal-methane clusters can give information on the structure of metal clusters that may otherwise be hard to obtain from isolated clusters. For example, the V3+(CH4)n (n = 1-3) experimental spectra show an additional peak as the second and third methane molecules are added to V3+, which indicates that the metal atoms are not equivalent. The Vx+(CH4) show a larger red shift in the symmetric C-H stretch for larger clusters with x = 5-8 than for the small clusters with x = 2, 3, indicating increased covalency in the interaction of larger vanadium clusters with methane.

19.
J Alzheimers Dis ; 96(2): 439-457, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37807781

RESUMO

Different investigations lead to the urgent need to generate validated clinical protocols as a tool for medical doctors to orientate patients under risk for a preventive approach to control Alzheimer's disease. Moreover, there is consensus that the combined effects of risk factors for the disease can be modified according to lifestyle, thus controlling at least 40% of cases. The other fraction of cases are derived from candidate genes and epigenetic components as a relevant factor in AD pathogenesis. At this point, it appears to be of critical relevance the search for molecular biomarkers that may provide information on probable pathological events and alert about early detectable risks to prevent symptomatic events of the disease. These precocious detection markers will then allow early interventions of non-symptomatic subjects at risk. Here, we summarize the status and potential avenues of prevention and highlight the usefulness of biological and reliable markers for AD.


Assuntos
Doença de Alzheimer , Humanos , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/genética , Doença de Alzheimer/prevenção & controle , Biomarcadores , Estilo de Vida , Fatores de Risco , Proteínas tau
20.
Front Oncol ; 13: 1239574, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37810980

RESUMO

Purpose: The purpose of this study was to evaluate the role of vacuum-assisted biopsy (VAB) in resecting breast cancers. Methods: Retrospective database analysis of 116 cancers [both invasive breast cancers (IC) and ductal carcinoma in situ (DCIS)] diagnosed by VAB submitted to standard surgical treatment with complete histological data from VAB and surgery. Excision following VAB was defined as complete resection (CR) if there was no residual tumor in the surgical specimen, minimal residual disease (MRD) if residual tumor ≤ 3 mm, gross residual disease (GRD) if residual tumor > 3 mm, and upgrade from DCIS on VAB to IC. CR and MRD were combined as potentially resected percutaneously (PRP). GRD and those with upgrade to IC were determined not eligible for percutaneous resection (NPR). Factors predictive of PRP were evaluated. Results: Mean age was 55.6 years (20-91; SD: 12,27). CR was seen in 29 of 116 cases (25%), MRD in 18 of 116 cases (15.5%), GRD in 64 of 116 cases (55.2%), and five of 116 cases (4.3%) were upgraded from DCIS to IC, and those groups combined represented 47 cases of PRP (40.5%) and 69 (59,5%) of NPR. For 77 tumors ≤ 10 mm, 45 (58.5%) were PRP. Multivariate analysis reveals significance for enlarged VAB (EVAB) (p = 0.008, OR: 4.4, 95% CI), low/intermediate nuclear grade (p < 0.001, OR: 12.5, 95% CI) and final tumor size (T) ≤ 10 mm (p = 0.001, OR: 50.1, 95% CI) for PRP. Conclusions: This study showed that lesions completely excised with VAB that were cancer could have been treated with VAB rather than surgery but tumor selection in terms of subtype and size is important.

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