RESUMO
The SARS-CoV-2 coronavirus encodes an essential papain-like protease domain as part of its non-structural protein (nsp)-3, namely SARS2 PLpro, that cleaves the viral polyprotein, but also removes ubiquitin-like ISG15 protein modifications as well as, with lower activity, Lys48-linked polyubiquitin. Structures of PLpro bound to ubiquitin and ISG15 reveal that the S1 ubiquitin-binding site is responsible for high ISG15 activity, while the S2 binding site provides Lys48 chain specificity and cleavage efficiency. To identify PLpro inhibitors in a repurposing approach, screening of 3,727 unique approved drugs and clinical compounds against SARS2 PLpro identified no compounds that inhibited PLpro consistently or that could be validated in counterscreens. More promisingly, non-covalent small molecule SARS PLpro inhibitors also target SARS2 PLpro, prevent self-processing of nsp3 in cells and display high potency and excellent antiviral activity in a SARS-CoV-2 infection model.
Assuntos
Antivirais/farmacologia , Proteases 3C de Coronavírus/antagonistas & inibidores , Proteases 3C de Coronavírus/metabolismo , SARS-CoV-2/metabolismo , Ubiquitina/metabolismo , Animais , Sítios de Ligação , Chlorocebus aethiops , Proteases 3C de Coronavírus/química , Proteases 3C de Coronavírus/genética , Cristalografia por Raios X , Citocinas/genética , Avaliação Pré-Clínica de Medicamentos/métodos , Reposicionamento de Medicamentos , Polarização de Fluorescência , Células HEK293 , Humanos , Cinética , Modelos Moleculares , Inibidores de Proteases/farmacologia , Conformação Proteica , SARS-CoV-2/química , SARS-CoV-2/genética , Ubiquitinas/genética , Células VeroRESUMO
Chinese hamster ovary (CHO) cells require cysteine for growth and productivity in fed-batch cultures. In intensified processes, supplementation of cysteine at high concentrations is a challenge due to its limited solubility and instability in solution. Methionine can be converted to cysteine (CYS) but key enzymes, cystathionine beta-synthase (Cbs) and cystathionine gamma-lyase (Cth), are not active in CHO cells resulting in accumulation of an intermediate, homocysteine (HCY), in cell culture milieu. In this study, Cbs and Cth were overexpressed in CHO cells to confer cysteine prototrophy, i.e., the ability to grow in a cysteine free environment. These pools (CbCt) needed homocysteine and beta-mercaptoethanol (ßME) to grow in CYS-free medium. To increase intracellular homocysteine levels, Gnmt was overexpressed in CbCt pools. The resultant cell pools (GnCbCt), post adaptation in CYS-free medium with decreasing residual HCY and ßME levels, were able to proliferate in the HCY-free, ßME-free and CYS-free environment. Interestingly, CbCt pools were also able to be adapted to grow in HCY-free and CYS-free conditions, albeit at significantly higher doubling times than GnCbCt cells, but couldn't completely adapt to ßME-free conditions. Further, single cell clones derived from the GnCbCt cell pool had a wide range in expression levels of Cbs, Cth and Gnmt and, when cultivated in CYS-free fed-batch conditions, performed similarly to the wild type (WT) cell line cultivated in CYS supplemented fed-batch culture. Intracellular metabolomic analysis showed that HCY and glutathione (GSH) levels were lower in the CbCt pool in CYS-free conditions but were restored closer to WT levels in the GnCbCt cells cultivated in CYS-free conditions. Transcriptomic analysis showed that GnCbCt cells upregulated several genes encoding transporters as well as methionine catabolism and transsulfuration pathway enzymes that support these cells to biosynthesize cysteine effectively. Further, 'omics analysis suggested CbCt pool was under ferroptotic stress in CYS-free conditions, which, when inhibited, enhanced the growth and viability of these cells in CYS-free conditions.
Assuntos
Cricetulus , Cisteína , Engenharia Metabólica , Células CHO , Animais , Cisteína/metabolismo , Cistationina beta-Sintase/genética , Cistationina beta-Sintase/metabolismo , Cistationina gama-Liase/genética , Cistationina gama-Liase/metabolismo , Cricetinae , Homocisteína/metabolismo , Homocisteína/genéticaRESUMO
On several key issues we agree with the commentators. Perhaps most importantly, everyone seems to agree that psychology has an important role to play in building better models of human vision, and (most) everyone agrees (including us) that deep neural networks (DNNs) will play an important role in modelling human vision going forward. But there are also disagreements about what models are for, how DNN-human correspondences should be evaluated, the value of alternative modelling approaches, and impact of marketing hype in the literature. In our view, these latter issues are contributing to many unjustified claims regarding DNN-human correspondences in vision and other domains of cognition. We explore all these issues in this response.
Assuntos
Cognição , Redes Neurais de Computação , HumanosRESUMO
Deep neural networks (DNNs) have had extraordinary successes in classifying photographic images of objects and are often described as the best models of biological vision. This conclusion is largely based on three sets of findings: (1) DNNs are more accurate than any other model in classifying images taken from various datasets, (2) DNNs do the best job in predicting the pattern of human errors in classifying objects taken from various behavioral datasets, and (3) DNNs do the best job in predicting brain signals in response to images taken from various brain datasets (e.g., single cell responses or fMRI data). However, these behavioral and brain datasets do not test hypotheses regarding what features are contributing to good predictions and we show that the predictions may be mediated by DNNs that share little overlap with biological vision. More problematically, we show that DNNs account for almost no results from psychological research. This contradicts the common claim that DNNs are good, let alone the best, models of human object recognition. We argue that theorists interested in developing biologically plausible models of human vision need to direct their attention to explaining psychological findings. More generally, theorists need to build models that explain the results of experiments that manipulate independent variables designed to test hypotheses rather than compete on making the best predictions. We conclude by briefly summarizing various promising modeling approaches that focus on psychological data.
Assuntos
Redes Neurais de Computação , Percepção Visual , Humanos , Percepção Visual/fisiologia , Visão Ocular , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Imageamento por Ressonância Magnética/métodosRESUMO
Soils play important roles in biological productivity. While past work suggests that microbes affect soil health and respond to agricultural practices, it is not well known how soil management shapes crop host microbiomes. To elucidate the impact of management on microbial composition and function in the sorghum microbiome, we performed 16S rRNA gene and ITS2 amplicon sequencing and metatranscriptomics on soil and root samples collected from a site in California's San Joaquin Valley that is under long-term cultivation with 1) standard (ST) or no tilling (NT) and 2) cover-cropping (CC) or leaving the field fallow (NO). Our results revealed that microbial diversity, composition, and function change across tillage and cover type, with a heightened response in fungal communities, versus bacterial. Surprisingly, ST harbored greater microbial alpha diversity than NT, indicating that tillage may open niche spaces for broad colonization. Across management regimes, we observed class-level taxonomic level shifts. Additionally, we found significant functional restructuring across treatments, including enrichment for microbial lipid and carbohydrate transport and metabolism and cell motility with NT. Differences in carbon cycling were also observed, with increased prevalence of glycosyltransferase and glycoside hydrolase carbohydrate active enzyme families with CC. Lastly, treatment significantly influenced arbuscular mycorrhizal fungi, which had the greatest prevalence and activity under ST, suggesting that soil practices mediate known beneficial plant-microbe relationships. Collectively, our results demonstrate how agronomic practices impact critical interactions within the plant microbiome and inform future efforts to configure trait-associated microbiomes in crops.Importance While numerous studies show that farming practices can influence the soil microbiome, there are often conflicting results on how microbial diversity and activity respond to treatment. In addition, there is very little work published on how the corresponding crop plant microbiome is impacted. With bacteria and fungi known to critically affect soil health and plant growth, we concurrently compared how the practices of no and standard tillage, in combination with either cover-cropping or fallow fields, shape soil and plant-associated microbiomes between the two classifications. In determining not only the response to treatment in microbial diversity and composition, but for activity as well, this work demonstrates the significance of agronomic practice in modulating plant-microbe interactions, as well as encourages future work on the mechanisms involved in community assemblages supporting similar crop outcomes.
RESUMO
Disasters and their more extensive and more serious variant, catastrophes, are different than most human experiences. They are inherently quite complex. Extensive and diverse resources are required to assist disaster survivors as well as disaster response personnel, and hospital medical staffs. Except for warfare, there are few other human predicaments that require such a massive and highly coordinated response. Traditional psycho-therapeutic interventions have little chance of being helpful in the acute stages of a disaster. Research demonstrates that selected crisis intervention processes provided by crisis-trained psychological support personnel have been quite successful in assisting both the survivors and responders in coping with disasters and catastrophes. Assistance to military personnel, emergency operations personnel, and survivors must be carefully crafted to assure that the right type of help is provided at the right time by the most appropriate, well-trained, and experienced personnel. This paper employed a scoping review methodology synthesizing the lessons gleaned from wars and past disasters beginning in the late 1800's up to the present. It sets a course for the appropriate management of the psychological impacts of future disasters and catastrophes. Evidence suggests effective psychiatric and psychological services provided during and in the aftermath of a disaster must be simple, brief, immediate, practical, and innovative. Most importantly, disaster mental health support services must consist of an integrated and comprehensive continuum of mental health services spanning all levels of intensity of support and care.
Assuntos
Desastres , Serviços de Saúde Mental , Transtornos de Estresse Pós-Traumáticos , Continuidade da Assistência ao Paciente , Humanos , Transtornos de Estresse Pós-Traumáticos/psicologia , Sobreviventes/psicologiaRESUMO
Chinese hamster ovary (CHO) cells in fed-batch cultures are known to consume large amounts of nutrients and divert significant portion of them towards the formation of byproducts, some of which, including lactate and ammonia, are known to be growth inhibitory in nature. A major fraction of these inhibitory metabolites are byproducts or intermediates of amino acid catabolism. Limiting the supply of amino acids has been shown to curtail the production of corresponding inhibitory byproducts resulting in enhanced growth and productivities in CHO cell fed-batch cultures (Mulukutla et al., 2017). In the current study, metabolic engineering of CHO cells was undertaken in order to reduce the biosynthesis of these novel growth inhibitors. Phenylalanine-tyrosine (Phe-Tyr) and branched chain amino acid (BCAA) catabolic pathways were engineered as part of this effort. Four genes that encode enzymes in the Phe-Tyr pathway, which were observed to be minimally expressed in CHO cells, were in turn overexpressed. Metabolically engineered cells were prototrophic to tyrosine and had reduced production of the inhibitory byproducts from Phe-Tyr pathway including 3-phenyllactate and 4-hydroxyphenyllactate. In case of BCAA catabolic pathway, branched chain aminotransferase 1 (BCAT1) gene, which encodes the enzyme that catalyzes the first step in the catabolism of BCAAs, was knocked out in CHO cells. Knockout (KO) of BCAT1 function completely eliminated production of inhibitory byproducts from BCAA catabolic pathway, including isovalerate, isobutyrate and 2-methylbutyrate, resulting in significantly enhanced cell growth and productivities in fed-batch cultures. This study is first of its kind to demonstrate that metabolic engineering of essential amino acid metabolism of CHO cells can significantly improve cell culture process performance.
Assuntos
Técnicas de Cultura Celular por Lotes , Inibidores do Crescimento/biossíntese , Inibidores do Crescimento/genética , Engenharia Metabólica , Aminoácidos/genética , Aminoácidos/metabolismo , Animais , Células CHO , Cricetinae , CricetulusRESUMO
OBJECTIVE: To evaluate the effects of intrathoracic insufflation on cardiorespiratory variables and working space in cats undergoing video-assisted thoracic surgery. STUDY DESIGN: Prospective randomized study. ANIMALS: Six healthy cats. METHODS: Cats were anesthetized using a standardized protocol. A Swan-Ganz catheter was positioned in the pulmonary artery under fluoroscopic guidance for measurement of cardiac output. Intrathoracic pressures (ITP) of 0 (baseline), 3, and 5 mm Hg were induced with CO2 and maintained for 30 minutes. Statistical comparison of cardiorespiratory variables was performed. After the procedures, all cats were recovered from anesthesia. Videos of thoracic working space at each ITP level were scored in a blinded fashion by 3 board-certified surgeons using a numerical scale from 0-10. RESULTS: All cats tolerated insufflation with 3 and 5 mm Hg for 30 minutes without oxygen desaturation, although ventilatory levels had to be increased substantially to maintain eucapnia and oxygenation. Cardiac index was not significantly different from baseline after 30 minutes at 3 mm Hg but was significantly lower after 30 minutes at 5 mm Hg compared with 3 mm Hg. Oxygen delivery was unaffected by 3 or 5 mm Hg compared with baseline. Scores for working space increased between baseline and 3 and 5 mm Hg but were not different between 3 and 5 mm Hg. CONCLUSION: CO2 insufflation to 5 mm Hg seems well tolerated in healthy cats, provided ventilatory settings are substantially increased as ITP increases. CLINICAL SIGNIFICANCE: Thoracic CO2 insufflation of 3 mm Hg in cats during video-assisted thoracic surgery is associated with less hemodynamic perturbation than 5 mm Hg insufflation and may provide the benefit of improved working space compared with baseline.
Assuntos
Dióxido de Carbono/administração & dosagem , Débito Cardíaco/efeitos dos fármacos , Doenças do Gato/cirurgia , Frequência Cardíaca/efeitos dos fármacos , Insuflação/veterinária , Cirurgia Torácica Vídeoassistida/veterinária , Animais , Gatos , Hemodinâmica/efeitos dos fármacos , Laparoscopia/métodos , Oxigênio , Pressão , Estudos Prospectivos , Cirurgia Torácica Vídeoassistida/métodosRESUMO
OBJECTIVE: To describe a technique for video-assisted thoracoscopic (VATS) thoracic duct ligation (TDL) in normal cats with a bipolar vessel-sealing device and to assess durability of the seal. STUDY DESIGN: Prospective case series. ANIMALS: Six healthy research cats. METHODS: Cats were placed under anesthesia for computed tomography lymphangiography (CTLA) to identify thoracic duct anatomy. On the basis of CTLA findings, cats were positioned in either right or left lateral recumbency for a 3-port VATS TDL. Thoracic duct branches were dissected from the aorta after subcutaneous indirect near-infrared fluorescence (NIRF) lymphography with indocyanine green was performed to optimize detection. A vessel-sealing device was used to seal each thoracic duct in 1 or more locations. Postattenuation, indirect NIRF lymphography was repeated to confirm complete occlusion of thoracic duct flow. CTLA was repeated in all cats 3 months postoperatively. RESULTS: The thoracic duct was surgically approached from the right in 3 cats and from the left in 3 cats. A median of 2.5 (range 1-6) TDL seal sites were applied. In 2 cats, leakage of chyle was detected during dissection. At 3 months postoperatively, CTLA confirmed reestablished chylous flow in 5 of 6 cats, appearing to occur through recanalization of previously sealed sites rather than through development of de novo lymphatic vessels. CONCLUSION: VATS TDL is feasible in cats, although the variable and delicate nature of feline thoracic duct anatomy should be considered preoperatively. CLINICAL SIGNIFICANCE: Bipolar vessel-sealing devices are not a durable modality for thoracic duct sealing in healthy cats in a seal only fashion.
Assuntos
Gatos/cirurgia , Ducto Torácico/cirurgia , Cirurgia Torácica Vídeoassistida/veterinária , Toracoscopia/veterinária , Animais , Feminino , Ligadura/veterinária , Linfografia , Estudos Prospectivos , Cirurgia Torácica Vídeoassistida/instrumentação , Cirurgia Torácica Vídeoassistida/métodos , Toracoscopia/instrumentação , Toracoscopia/métodosRESUMO
Medication adherence is an important determinant of transplant outcomes. Attempts to investigate adherence are frequently undermined by selection bias: It is very hard to recruit and retain non-adherent patients in research efforts. This manuscript presents recruitment strategies and results from the MALT (Medication Adherence in children who had a Liver Transplant) multisite prospective cohort study. MALT sites recruited 400 pediatric liver transplant patients who agreed to be followed for 2 years. The primary purpose was to determine whether a marker of adherence, the Medication Level Variability Index (MLVI), predicts rejection outcomes. The present manuscript describes methods used in MALT to ensure that a representative sample was recruited, and presents detailed recruitment results. MALT sites were able to recruit a nationally representative sample, as determined by a comparison between the MALT cohort and a national sample of transplant recipients. Strategies that helped ensure that the sample was representative included monitoring of the outcome measure in comparison with a national sample, drastically limiting patient burden, and specific recruitment methods. We discuss the importance of a representative sample in adherence research and recommend that future efforts to study adherence pay special attention to sample characteristics.
Assuntos
Rejeição de Enxerto/prevenção & controle , Imunossupressores/uso terapêutico , Transplante de Fígado , Adesão à Medicação , Adolescente , Criança , Pré-Escolar , Técnicas de Apoio para a Decisão , Feminino , Seguimentos , Rejeição de Enxerto/diagnóstico , Rejeição de Enxerto/etiologia , Humanos , Lactente , Masculino , Adesão à Medicação/estatística & dados numéricos , Seleção de Pacientes , Estudos Prospectivos , Viés de SeleçãoRESUMO
OBJECTIVE: To describe the technique and outcomes of laparoscopic adrenalectomy (LA) in cats with adrenocortical neoplasia. STUDY DESIGN: Retrospective case series. ANIMALS: Eleven client-owned cats with unilateral adrenal tumors. METHODS: Medical records of cats that underwent LA for unilateral functional adrenal tumors at 3 veterinary teaching hospitals were reviewed. Data collected included signalment, clinical signs, physical examination findings, diagnostic imaging results, preoperative laboratory tests, laparoscopic port placement and techniques, duration of anesthesia and surgery, complications, concomitant procedures, need for conversion to an open celiotomy, histopathological diagnosis, and postoperative survival. RESULTS: Eleven cats were included, 5 with right-sided and 6 with left-sided tumors. Tumors were aldosterone-secreting (n = 8), progesterone-secreting (n = 2), or testosterone-secreting (n = 1). Adrenalectomy was successfully performed in all 11 cats although 4 cases required conversion to an open celiotomy, due to poor visualization (n = 2), close adherence of the tumor to the caudal vena cava (n = 1), and inability to maintain adequate pneumoperitoneum (n = 1). Ten of the 11 cats were discharged from the hospital, with a median survival time of 803 days (range 467-1123 days). One cat died from severe pancreatitis and cardiogenic pulmonary edema. CONCLUSION: Adrenalectomy can be performed in cats via laparoscopy but is technically challenging, and associated with a relatively high conversion rate (36%).
Assuntos
Neoplasias do Córtex Suprarrenal/veterinária , Adrenalectomia/veterinária , Doenças do Gato/cirurgia , Neoplasias do Córtex Suprarrenal/cirurgia , Adrenalectomia/métodos , Animais , Gatos , Feminino , Humanos , Laparoscopia/veterinária , Masculino , Estudos Retrospectivos , Resultado do TratamentoRESUMO
[Purpose] To present the increase in thoracic kyphosis in a patient suffering from exertional dyspnea, reduced lung capacity, and spinal pains related to straight back syndrome (SBS). [Subject and Methods] A 33-year-old male patient was put on a CBP® corrective care program involving mirror image® traction procedures designed to increase the thoracic kyphosis. [Results] This patient had a 10° improvement in thoracic kyphosis in 16-weeks that was maintained 7-months later. There was a simultaneous reduction of pain, resolved exertional dyspnea, and a greater than 2 liter increase in lung capacity. [Conclusion] This case illustrates that nonsurgical improvement in thoracic kyphosis in a patient with SBS is possible and that this may positively influence lung capacity, health and function.
RESUMO
BACKGROUND: Germline DNA mutations that increase the susceptibility of a patient to certain cancers have been identified in various genes, and patients can be screened for mutations in these genes to assess their level of risk for developing cancer. Traditional methods using Sanger sequencing focus on small groups of genes and therefore are unable to screen for numerous genes from several patients simultaneously. The goal of the present study was to validate a 25-gene panel to assess genetic risk for cancer in 8 different tissues using next generation sequencing (NGS) techniques. METHODS: Twenty-five genes associated with hereditary cancer syndromes were selected for development of a panel to screen for risk of these cancers using NGS. In an initial technical assessment, NGS results for BRCA1 and BRCA2 were compared with Sanger sequencing in 1864 anonymized DNA samples from patients who had undergone previous clinical testing. Next, the entire gene panel was validated using parallel NGS and Sanger sequencing in 100 anonymized DNA samples. Large rearrangement analysis was validated using NGS, microarray comparative genomic hybridization (CGH), and multiplex ligation-dependent probe amplification analyses (MLPA). RESULTS: NGS identified 15,877 sequence variants, while Sanger sequencing identified 15,878 in the BRCA1 and BRCA2 comparison study of the same regions. Based on these results, the NGS process was refined prior to the validation of the full gene panel. In the validation study, NGS and Sanger sequencing were 100% concordant for the 3,923 collective variants across all genes for an analytical sensitivity of the NGS assay of >99.92% (lower limit of 95% confidence interval). NGS, microarray CGH and MLPA correctly identified all expected positive and negative large rearrangement results for the 25-gene panel. CONCLUSION: This study provides a thorough validation of the 25-gene NGS panel and indicates that this analysis tool can be used to collect clinically significant information related to risk of developing hereditary cancers.
Assuntos
Genes BRCA1 , Genes BRCA2 , Predisposição Genética para Doença , Sequenciamento de Nucleotídeos em Larga Escala , Síndromes Neoplásicas Hereditárias/epidemiologia , Síndromes Neoplásicas Hereditárias/genética , Hibridização Genômica Comparativa , Biologia Computacional/métodos , Testes Genéticos , Genômica/métodos , Mutação em Linhagem Germinativa , Humanos , Mutação , Reprodutibilidade dos Testes , Risco , Sensibilidade e EspecificidadeRESUMO
Respiratory syncytial virus (RSV) is a major cause of respiratory tract infections in infants, young children and adults. Compound 1a (9b-(4-chlorophenyl)-1-(4-fluorobenzoyl)-1,2,3,9b-tetrahydro-5H-imidazo[2,1-a]isoindol-5-one) was identified as an inhibitor of A and B strains of RSV targeting the fusion glycoprotein. SAR was developed by systematic exploration of the phenyl (R(1)) and benzoyl (R(2)) groups. Furthermore, introduction of a nitrogen at the 8-position of the tricyclic core resulted in active analogues with improved properties (aqueous solubility, protein binding and logD) and excellent rat pharmacokinetics (e.g., rat oral bioavailability of 89% for compound 17).
Assuntos
Antivirais/farmacologia , Imidazóis/farmacologia , Fusão de Membrana/efeitos dos fármacos , Vírus Sinciciais Respiratórios/efeitos dos fármacos , Antivirais/química , Descoberta de Drogas , Humanos , Imidazóis/química , Vírus Sinciciais Respiratórios/fisiologia , Relação Estrutura-AtividadeRESUMO
Respiratory syncytial virus (RSV) is a major cause of respiratory tract infections in infants, young children and adults. 1,2,3,9b-Tetrahydro-5H-imidazo[2,1-a]isoindol-5-ones with general structure 1 were previously identified as promising inhibitors of RSV targeting the fusion glycoprotein. In particular, the introduction of a nitrogen at the 8-position of the tricyclic core yielded lead compounds 2 and 3. Extensive exploration of the R(2) group established that certain heterocyclic amides conferred potent RSV A&B activity and a good balance of physicochemical and pharmacokinetic properties. The antiviral activity was found to reside in a single enantiomer and compound 33a, (9bS)-9b-(4-chlorophenyl)-1-(pyridin-3-ylcarbonyl)-1,2,3,9b-tetrahydro-5H-imidazo[1',2':1,2]pyrrolo[3,4-c]pyridin-5-one (known as BTA9881), was identified as a candidate for preclinical development.
Assuntos
Antivirais/farmacologia , Imidazóis/farmacologia , Fusão de Membrana/efeitos dos fármacos , Vírus Sinciciais Respiratórios/efeitos dos fármacos , Humanos , Vírus Sinciciais Respiratórios/fisiologiaRESUMO
A 3-yr-old female spayed grizzly bear (Ursus arctos horribilis) was evaluated for seizure activity along with lethargy, inappetence, dull mentation, and aggressive behavior. Magnetic resonance (MR) examination of the brain revealed a contrast-enhanced right cerebellar mass with multifocal smaller nodules located in the left cerebellum, thalamus, hippocampus, and cerebrum with resultant obstructive hydrocephalus. Cerebrospinal fluid analysis revealed mild mononuclear pleocytosis, with differentials including inflammatory versus neoplastic processes. Blood and cerebrospinal fluid were also submitted for polymerase chain reaction and agar gel immunodiffusion to rule out infectious causes of meningitis/encephalitis. While awaiting these results, the bear was placed on steroid and antibiotic therapy. Over the next week, the bear deteriorated; she died 1 wk after MR. A complete postmortem examination, including immunohistochemisty, revealed the cerebellar mass to be a medulloblastoma. This is the only case report, to the authors' knowledge, describing a medulloblastoma in a grizzly bear.
Assuntos
Neoplasias Encefálicas/veterinária , Meduloblastoma/veterinária , Ursidae , Animais , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/patologia , Evolução Fatal , Feminino , Meduloblastoma/diagnóstico , Meduloblastoma/patologiaRESUMO
The design, synthesis and structure-activity relationships of a series of oxazole-benzamide inhibitors of the essential bacterial cell division protein FtsZ are described. Compounds had potent anti-staphylococcal activity and inhibited the cytokinesis of the clinically-significant bacterial pathogen Staphylococcus aureus. Selected analogues possessing a 5-halo oxazole also inhibited a strain of S. aureus harbouring the glycine-to-alanine amino acid substitution at residue 196 of FtsZ which conferred resistance to previously reported inhibitors in the series. Substitutions to the pseudo-benzylic carbon of the scaffold improved the pharmacokinetic properties by increasing metabolic stability and provided a mechanism for creating pro-drugs. Combining multiple substitutions based on the findings reported in this study has provided small-molecule inhibitors of FtsZ with enhanced in vitro and in vivo antibacterial efficacy.
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Benzamidas/farmacologia , Proteínas do Citoesqueleto/antagonistas & inibidores , Desenho de Fármacos , Oxazóis/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/síntese química , Antibacterianos/química , Benzamidas/química , Relação Dose-Resposta a Droga , Testes de Sensibilidade Microbiana , Estrutura Molecular , Oxazóis/química , Staphylococcus aureus/química , Relação Estrutura-AtividadeRESUMO
Papain-like protease (PLpro) is an attractive drug target for SARS-CoV-2 because it is essential for viral replication, cleaving viral poly-proteins pp1a and pp1ab, and has de-ubiquitylation and de-ISGylation activities, affecting innate immune responses. We employ Deep Mutational Scanning to evaluate the mutational effects on PLpro enzymatic activity and protein stability in mammalian cells. We confirm features of the active site and identify mutations in neighboring residues that alter activity. We characterize residues responsible for substrate binding and demonstrate that although residues in the blocking loop are remarkably tolerant to mutation, blocking loop flexibility is important for function. We additionally find a connected network of mutations affecting activity that extends far from the active site. We leverage our library to identify drug-escape variants to a common PLpro inhibitor scaffold and predict that plasticity in both the S4 pocket and blocking loop sequence should be considered during the drug design process.
Assuntos
Mutação , SARS-CoV-2 , SARS-CoV-2/genética , Humanos , Proteases Semelhantes à Papaína de Coronavírus/genética , Proteases Semelhantes à Papaína de Coronavírus/metabolismo , Proteases Semelhantes à Papaína de Coronavírus/química , Domínio Catalítico , Antivirais/farmacologia , Proteases 3C de Coronavírus/genética , Proteases 3C de Coronavírus/metabolismo , Proteases 3C de Coronavírus/antagonistas & inibidores , Proteases 3C de Coronavírus/química , COVID-19/virologia , Tratamento Farmacológico da COVID-19 , Modelos Moleculares , Células HEK293RESUMO
The bacterial cell division protein FtsZ is an attractive target for small-molecule antibacterial drug discovery. Derivatives of 3-methoxybenzamide, including compound PC190723, have been reported to be potent and selective antistaphylococcal agents which exert their effects through the disruption of intracellular FtsZ function. Here, we report the further optimization of 3-methoxybenzamide derivatives towards a drug candidate. The in vitro and in vivo characterization of a more advanced lead compound, designated compound 1, is described. Compound 1 was potently antibacterial, with an average MIC of 0.12 µg/ml against all staphylococcal species, including methicillin- and multidrug-resistant Staphylococcus aureus and Staphylococcus epidermidis. Compound 1 inhibited an S. aureus strain carrying the G196A mutation in FtsZ, which confers resistance to PC190723. Like PC190723, compound 1 acted on whole bacterial cells by blocking cytokinesis. No interactions between compound 1 and a diverse panel of antibiotics were measured in checkerboard experiments. Compound 1 displayed suitable in vitro pharmaceutical properties and a favorable in vivo pharmacokinetic profile following intravenous and oral administration, with a calculated bioavailability of 82.0% in mice. Compound 1 demonstrated efficacy in a murine model of systemic S. aureus infection and caused a significant decrease in the bacterial load in the thigh infection model. A greater reduction in the number of S. aureus cells recovered from infected thighs, equivalent to 3.68 log units, than in those recovered from controls was achieved using a succinate prodrug of compound 1, which was designated compound 2. In summary, optimized derivatives of 3-methoxybenzamide may yield a first-in-class FtsZ inhibitor for the treatment of antibiotic-resistant staphylococcal infections.
Assuntos
Antibacterianos/farmacocinética , Proteínas de Bactérias/antagonistas & inibidores , Benzamidas/farmacocinética , Proteínas do Citoesqueleto/antagonistas & inibidores , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Oxazóis/farmacocinética , Pró-Fármacos/farmacocinética , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus epidermidis/efeitos dos fármacos , Succinatos/farmacocinética , Administração Oral , Animais , Antibacterianos/síntese química , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Benzamidas/síntese química , Benzamidas/química , Benzamidas/farmacologia , Disponibilidade Biológica , Contagem de Colônia Microbiana , Citocinese/efeitos dos fármacos , Proteínas do Citoesqueleto/genética , Farmacorresistência Bacteriana Múltipla , Feminino , Injeções Intravenosas , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Camundongos , Testes de Sensibilidade Microbiana , Mutação , Oxazóis/síntese química , Oxazóis/farmacologia , Pró-Fármacos/síntese química , Pró-Fármacos/farmacologia , Infecções Estafilocócicas/microbiologia , Staphylococcus epidermidis/crescimento & desenvolvimento , Succinatos/síntese química , Succinatos/farmacologia , Ácido Succínico/química , Coxa da Perna/microbiologia , Resultado do TratamentoRESUMO
How does structural racism influence where people are killed during encounters with police? We analyzed geo-located incidents of fatal encounters with police that occurred between 2000 and 2020 in Census tracts that received a classification by the Home Owners Loan Corporation (HOLC) during the 1930's. Statistical models show that incidents of fatal encounters with police in formerly redlined areas are 66% more likely than in zones that received the most favorable "A" rating. These differences remain even when tract historical and contemporary racial compositions, along with contemporary economic conditions, are taken into account. The effects of contemporary racial composition and economic conditions overshadow the effect of zone classifications only in areas with high proportions of Black residents or residents in poverty (>60% or >30% respectively). These findings provide evidence of structural biases in policing rooted in historical segregation policies.