Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 122
Filtrar
1.
Can Urol Assoc J ; 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38587978

RESUMO

INTRODUCTION: Urologists observed reduced cancer consultations and surgeries during the SARS-CoV-2 pandemic, raising concern about treatment delays. Testicular cancer serves as a particularly sensitive marker of this phenomenon, as the clinical stage of testicular cancer at presentation is predictive of cancer-specific survival. We aimed to investigate whether COVID-related restrictions to primary care access resulted in increased incidence of metastatic germ cell testis cancer. METHODS: A retrospective chart review was conducted on all cases of testicular cancer managed surgically at our center from March 1, 2018, to February 28, 2023. Patients were categorized into temporal cohorts, representing before, during, and following the implementation of COVID-19 public health restrictions in the province of Newfoundland and Labrador. RESULTS: Forty-one cases of testicular germ cell tumors were identified during the study period. The mean age at diagnosis was 40.8 years (standard deviation ±13.7). Demographics did not vary across the cohorts. Clinical stage 3 disease remained stable before and during the pandemic at 10.5% and 9.1% of cases, respectively. In the post-pandemic period, there was an increase to 27.3% (p=0.617). Surgical wait times remained stable across the pandemic (p=0.151). CONCLUSIONS: There was a 16.8% rise in clinical stage III disease from the pre-pandemic to post-pandemic period. Our study failed to identify a statistically significant increase in metastatic testis cancer incidence upon lifting of pandemic restrictions. Further study is necessary to confirm suspicions that pandemic restrictions contributed to increased incidence of metastatic testis cancer.

2.
Can Urol Assoc J ; 18(4): E113-E119, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38381938

RESUMO

INTRODUCTION: Renal cell carcinoma (RCC) is often associated with significant morbidity and mortality, with overall survival contingent on multiple factors - most importantly, disease stage at diagnosis. Disruptions in healthcare delivery during the COVID-19 pandemic have resulted in various reported diagnostic and treatment delays, which have had detrimental impacts on malignancies such as RCC. METHODS: Surgically managed cases of RCC at our center were identified using a retrospective chart review of all nephrectomies conducted from March 1, 2018, to February 28, 2023. Examination of disease characteristics in three time period cohorts (before, during, and following the COVID-19 pandemic) was undertaken. Timeframes were consistent with implementation and abolition of public health restrictions in the province of Newfoundland and Labrador. RESULTS: A total of 483 surgically managed RCC cases were identified during the study period. The median age was 65 years (interquartile range [IQR] 56-71), and 62.3% of patients were male. Demographics did not vary across timeframes. Before and during the pandemic, pathologic stage 3 (pT3) disease was reported in 38.9% and 35.4% of cases, respectively, whereas the post-pandemic period saw this presentation in 50.0% of patients. Surgical wait times increased significantly across study timeframes (p=0.003). CONCLUSIONS: The first year following the COVID-19 pandemic saw an 11.1% increase in patients presenting with pT3 RCC. These findings are suggestive of a clinically significant stage migration, which paired with prolonged wait times for surgery, provide critical consideration in the urgency of diagnostic and treatment decisions for RCC in the immediate future.

3.
J Org Chem ; 89(5): 3211-3213, 2024 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-38333986

RESUMO

An α-methyl, non-natural amino acid (NNAA) building block equipped with an alkyl halide tail that could be readily transformed into an organozinc was prepared. This single organometallic was cross-coupled to an array of heterocyclic electrophiles using the Pd-PEPPSI-IHeptCl catalyst to produce a wide selection of optically pure α-methyl NNAAs. With these in hand, non-natural peptides are being produced for evaluation in a variety of therapeutic areas in drug discovery.


Assuntos
Aminoácidos , Descoberta de Drogas , Peptídeos
4.
Cureus ; 15(11): e48815, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38106763

RESUMO

Penile cancer is a rare genitourinary malignancy for which limited treatment options exist beyond primary surgical resection. Metastatic lymphadenopathy represents a particularly poor prognosis with a lack of literature to suggest the effectiveness of radiation or systemic therapies. Our case documents an inguinal recurrence of penile squamous cell carcinoma not amenable to surgical intervention demonstrating complete response to salvage radiotherapy in the palliative setting. These observations propose the need for further research around the utility of radiotherapy in the management of metastatic penile malignancies.

5.
Can Urol Assoc J ; 17(5): E134-E140, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36758180

RESUMO

INTRODUCTION: Penile carcinomas represent a rare malignancy associated with significant psychosocial impacts that deter afflicted individuals from seeking medical attention, thus, worsening prognosis. Following the dramatic shift in healthcare delivery to virtual platforms, it is suspected that prevalent psychosocial impacts have been further compounded by the COVID-19 pandemic, resulting in several late-stage presentations and engendering poorer outcomes. METHODS: A retrospective chart review of surgically managed cases of penile cancer was conducted from January 2020 to June 2022 to identify patients that may have been unduly impacted by the COVID-19 pandemic. Included cases were analyzed in quantifying diagnostic and treatment delays, along with patient outcomes. Relevant epidemiological and pathological markers were also examined. RESULTS: Ten patients met the inclusion criteria. Average time delay from first complaint of a penile lesion to surgical management was 75 days, with 60% of patients experiencing a time delay of two months or more. The average delay from first complaint to diagnosis was 62 days in 2020 and 18 days in 2021. Advanced-stage disease was present in six (60%) individuals at presentation, while four (40%) patients perished during the study period. CONCLUSIONS: In cases of concern for penile malignancy, virtual care cannot replace the necessity of physical exams in preventing diagnostic and treatment delays. The present study further highlights the necessity of initial physical examination of penile abnormalities in preventing fatal outcomes for those afflicted. Such consideration warrants urgent examination of referred males with genital abnormalities to prevent further exacerbation of delays.

6.
Chemistry ; 28(35): e202200665, 2022 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35470486

RESUMO

Bulky Pd-N-heterocyclic carbene (NHC) catalysts (e. g., N-(di-2,6-(3-pentyl)phenyl), IPent) have been shown to have significantly higher reactivity in a wide variety of cross-coupling applications (i. e., C-C, C-S, C-N) than less hindered variants (e. g., N-(di-2,6-(isopropyl)phenyl), IPr). Further, chlorinating the backbone of the NHC ring sees an even greater increase in reactivity. In the cross-coupling of (hetero)aryl electrophiles to secondary alkyl nucleophiles, making the N-aryl groups larger reduces the amount of ß-hydride elimination leading to alkene byproducts and chlorinating the NHC core had an even greater effect, all but eliminating alkene formation. In the present study involving the cross-coupling of primary alkyl electrophiles and nucleophiles, a sharp and surprising reversal of all of the above trends was observed. Bulkier catalysts had generally slower rate of reaction and ß-hydride elimination worsened leading to extensive amounts of alkene byproducts.

7.
J Med Chem ; 64(18): 13540-13550, 2021 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-34473495

RESUMO

The polyprenyl lipid undecaprenyl phosphate (C55P) is the universal carrier lipid for the biosynthesis of bacterial cell wall polymers. C55P is synthesized in its pyrophosphate form by undecaprenyl pyrophosphate synthase (UppS), an essential cis-prenyltransferase that is an attractive target for antibiotic development. We previously identified a compound (MAC-0547630) that showed promise as a novel class of inhibitor and an ability to potentiate ß-lactam antibiotics. Here, we provide a structural model for MAC-0547630's inhibition of UppS and a structural rationale for its enhanced effect on UppS from Bacillus subtilis versus Staphylococcus aureus. We also describe the synthesis of a MAC-0547630 derivative (JPD447), show that it too can potentiate ß-lactam antibiotics, and provide a structural rationale for its improved potentiation. Finally, we present an improved structural model of clomiphene's inhibition of UppS. Taken together, our data provide a foundation for structure-guided drug design of more potent UppS inhibitors in the future.


Assuntos
Alquil e Aril Transferases/metabolismo , Proteínas de Bactérias/metabolismo , Inibidores Enzimáticos/metabolismo , Alquil e Aril Transferases/química , Bacillus subtilis/enzimologia , Proteínas de Bactérias/química , Domínio Catalítico , Cristalografia por Raios X , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Staphylococcus aureus Resistente à Meticilina/enzimologia , Testes de Sensibilidade Microbiana , Estrutura Molecular , Ligação Proteica , Relação Estrutura-Atividade
8.
J Org Chem ; 86(15): 10343-10359, 2021 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-34254799

RESUMO

(DiMeIHeptCl)Pd, a hyper-branched N-aryl Pd NHC catalyst, has been shown to be efficient at performing amine arylation reactions in solvent-free ("melt") conditions. The highly lipophilic environment of the alkyl chains flanking the Pd center serves as lubricant to allow the complex to navigate through the paste-like environment of these mixtures. The protocol can be used on a multi-gram scale to make a variety of aniline derivatives, including substrates containing alcohol moieties.

9.
Chemistry ; 27(49): 12535-12539, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34190367

RESUMO

NaBHT (sodium 2,6-di-tert-butyl-4-methylphenolate), a strong, but hindered and lipophilic base, has been effectively paired with similarly lipophilic, high-reactivity Pd-NHC (N-heterocyclic carbene) catalysts to produce an ideal combination for performing solvent-free (melt) cross-coupling amination. The mild nucleophilicity of NaBHT, coupled with the anti-oxidant properties of its conjugate acid byproduct, BHT means the process seems to have no functional group incompatibilities. Highly effective coupling of base-sensitive and redox-active functional groups was observed in all cases with only 0.1-0.2 mol percent catalyst. Comparisons using the standard base for this reaction, KOtBu, led to poor couplings or complete degradation in most applications - only NaBHT works.


Assuntos
Hidroxitolueno Butilado , Sódio , Aminação , Catálise , Solventes
10.
Cureus ; 13(4): e14239, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33959434

RESUMO

Adrenocortical carcinoma (ACC) is a rare, highly malignant endocrine tumor, often associated with a poor prognosis. Most patients who develop ACC are either children of ages 1-6, or adults in their fourth to fifth decade of life. Individuals with a functional cortisol-secreting ACC frequently present with Cushing syndrome. We report a case of an 18-year-old male who was found to have a large ACC tumor, with thrombus extension into the inferior vena cava (IVC), after presenting with Cushing syndrome. ACC presents a challenging scenario for physicians as surgical resection remains the only form of curative therapy, however, despite such treatment many patients quickly develop metastases.

11.
Angew Chem Int Ed Engl ; 60(38): 20606-20626, 2021 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-33811800

RESUMO

Process analytical technology (PAT) is a system designed to help chemists better understand and control manufacturing processes. PAT systems operate through the combination of analytical devices, reactor control elements, and mathematical models to ensure the quality of the final product through a quality by design (QbD) approach. The expansion of continuous manufacturing in the pharmaceutical and fine-chemical industry requires the development of PAT tools suitable for continuous operation in the environment of flow reactors. This requires innovative approaches to sampling and analysis from flowing media to maintain the integrity of the reactor content and the analyte of interest. The following Review discusses examples of PAT tools implemented in flow chemistry for the preparation of small organic molecules, and applications of self-optimization tools.

12.
Chemistry ; 27(11): 3855-3860, 2021 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-33617055

RESUMO

Two similar tridentate directing groups derived from glycine and 8-aminoquinoline were shown to enable the palladium-catalyzed anti-Markovnikov hydrofunctionalization of 4-pentenylamine with drastically different efficiencies. A computational investigation into the origin of the reactivity difference between these isomeric, carbonyl-transposed auxiliaries suggests that protonation state, thus charge of the substrate-metal complex prior to nucleopalladation is key. These investigations have culminated in a directing group design that can undergo Pd-catalyzed hydrofunctionalization under relatively mild conditions, as low as room temperature.

13.
Anal Chem ; 93(8): 3905-3913, 2021 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-33605714

RESUMO

Chiral active pharmaceutical ingredients (APIs) are known to bind to chiral biological targets with better on-target specificity than achiral ones. However, the methods of synthesizing such APIs stereoselectively require the exhaustive optimization of multiple quality attributes of an asymmetric synthesis, wherein all critical quality attributes (for example, chemical and stereochemical purity of the API) are to be optimized in parallel and ideally from the beginning of the drug development program. A multidimensional liquid chromatographic tool capable of simultaneously measuring multiple quality attributes from a single analytical injection is reported. The tool is designed for the recirculation of chromatographic eluent bearing an analyte of interest through one or more stationary phases using a new and uniquely designed heart-cut valve. The iterative measurement of a target analyte from just one single injection will help scientists identify whether an unknown impurity is formed during reaction or during analysis. This chromatographic tool is particularly useful in the discovery of on-analysis artifacts, which is a resource-intensive exercise involving the identification, synthesis, and injection of impurity standards, all of which delay the drug development program.

14.
Angew Chem Int Ed Engl ; 60(22): 12224-12241, 2021 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-32986262

RESUMO

The first cross-coupling of organozinc nucleophiles with aryl halides was reported in 1977 by Negishi. Unknown to all at the time was the importance of salt additives that were often present as a byproduct from the organozinc preparation. For decades, these salt additives were overlooked until 2006 when it was discovered that two different, yet effective methods for preparing organozinc solutions (i.e. one with salt and one without) provided drastically different results. Since this finding, the exact role of salt additives in cross-coupling has been debated in the catalysis community. In this Review we highlight all the major discoveries regarding the influence of salt additives on the formation of organozinc reagents and their use in the Negishi reaction. These effects include solubilizing key intermediates, the formation of higher-order zincates, product inhibition, catalyst protection, and solvent effects.

15.
Can Urol Assoc J ; 15(4): E221-E226, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33007179

RESUMO

INTRODUCTION: Testicular cancer is the most commonly diagnosed malignancy in young males. Testicular examination is a non-invasive and inexpensive means of detecting testicular cancer at an early stage. In this project, a set of 3D-printed models was developed to facilitate teaching testicular examination and improving understanding of testicular malignancies among patients and medical learners. METHODS: Five scrotum models were designed: a control model with healthy testes, and four models containing a healthy testicle and a testicle with an endophytic mass of varying size. The anatomy, texture, and composition of the 3D-printed models were refined using an iterative process between the design team and urologists. The completed models were assessed by six urologists, two urology nurse practitioners, and 32 medical learners. Participants were asked to inspect and palpate each model, and to provide feedback using a five-point Likert scale. RESULTS: Clinicians reported that the models enabled accurate simulation of a testicular examination involving both healthy and pathologic testes (χ̄=4.3±1.0). They agreed that the models would be useful teaching tools for both medical learners (χ̄=4.8±0.5) and patients (χ̄=4.8±0.7). Following an educational session with the models, medical learners reported improvements in confidence and skill in performing a testicular examination. CONCLUSIONS: 3D-printed models can effectively simulate palpation of both healthy and pathologic testes. The developed models have the potential to be a useful adjunct in teaching testicular examination and in demonstrating abnormal findings that require further investigation.

16.
Chemistry ; 26(67): 15505-15508, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33098259

RESUMO

Optimization of the asymmetric synthesis of warfarin, an important anticoagulant, has been evaluated using a reconfigurable reaction platform capable of performing batch, continuous flow, and plug-flow synthesis. Further, this platform has been integrated with a novel, multidimensional, multiple variable analysis tool that can evaluate multiple critical quality attributes (CQA), percent conversion and enantiomeric excess in this case, from a single injection that is repeatedly recycled in a closed loop of chromatography columns, a detector and a heart-cut valve. Further, the new, integrated analysis system also facilitates validation of each QA, providing a high-level of confidence in analytical measurements, which are obtained without operator intervention.

17.
Cureus ; 12(7): e9020, 2020 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-32775100

RESUMO

The current generation of graduating medical students is entering into practice with minimal exposure to the digital rectal examination (DRE), a necessary component of a complete physical examination. Simulation-based medical education (SBME) using anatomical silicone models and task trainers can provide hands-on training opportunities for medical students to rehearse DREs. However, there is a scarcity of affordable, validated, and anatomically correct silicone prostate models and task trainers for rehearsing DREs. This technical report describes and validates evidence for silicone prostate models and a DRE task trainer created from three-dimensional (3D)-printed molds for medical student- and resident-training and clinical skills maintenance. A pre-existing 3D human model and five different prostate models from open-source, royalty-free websites were converted using Fusion360™ (Autodesk Inc., San Rafael, CA) into stereolithography files and altered to produce negative molds. The prostate molds were filled with silicone and polylactic acid filament "nodules". The buttocks were isolated from the human model and an anal canal was designed with a larger cavity on the interior to hold the silicone prostate models to simulate a real DRE. Five practicing urologists were recruited to evaluate the 3D-printed silicone prostate models and the DRE task trainer. The participants were provided with a qualitative survey and asked to rate the perceived realism and educational effectiveness of the prostate models and task trainer. The silicone models and task trainer were found to be useful for simulation training when attempting DRE techniques. The feedback from the participants was positive overall and provided recommendations for improvement including stabilizing the prostate models in the task trainer, smoothening the transition between the rectum and the prostate, and adding an additional "normal" prostate model. Silicone prostate models and DRE task trainers created from 3D molds are economical and anatomically and tactically accurate training tools to teach and maintain DRE skills as compared to commercially available, cost-prohibitive models. After making the suggested and appropriate modifications, the prostate models and DRE task trainer could potentially be used as tools for clinical skills training and maintenance and for patient education in the future.

18.
Cureus ; 12(6): e8544, 2020 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-32670681

RESUMO

Urothelial carcinoma in a crossed fused renal ectopia (CFRE) is an exceedingly rare clinical finding. We describe the surgical management used to treat upper tract urothelial carcinoma in a 64-year-old man with a right-to-left CFRE. Nephroureterectomy with bladder cuff excision was the treatment of choice. The fused kidney was carefully dissected until an area of demarcation emerged between the vasculature supplying the left and right moieties. Pressure was applied to the isthmus separating the two moieties, and a sharp incision was made to release the left moiety. The operation was completed with limited blood loss. Pathology revealed a high-grade T3 papillary urothelial carcinoma with negative margins. To our knowledge, the case is the first to report urothelial carcinoma in a right-to-left CFRE.

19.
Chemistry ; 26(21): 4861-4865, 2020 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-32196778

RESUMO

The role that LiBr plays in the lifetime of Pd-NHC complexes has been investigated. A bromide ion is proposed to coordinate to Pd thereby preventing beta hydride elimination (BHE) (to form NHC-H+ ) of the reductive elimination (RE) intermediate that normally completes with the desired cross-coupling catalytic cycle. Coordinating groups, such as anilines, are able to bind suitably well to Pd to prevent this pathway from occurring, thus reducing the need for the added salt. The metal hydride formed from BHE is very unstable and RE of the hydride to the NHC ligand occurs very rapidly giving rise to the corresponding hydrido-NHC (i.e., NHC-H+ ). The use of the per deuterated dibutylzinc shows a significant deuterium isotope effect, shutting down catalyst death almost completely. The use of bis-neopentylzinc, now possessing no hydrides, eliminates catalyst death all together leading to a very long-lived catalytic cycle and confirming the untoward role of BHE.

20.
Nat Chem Biol ; 16(2): 143-149, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31768032

RESUMO

Staphylococcus aureus is the leading cause of infections worldwide, and methicillin-resistant strains (MRSA) are emerging. New strategies are urgently needed to overcome this threat. Using a cell-based screen of ~45,000 diverse synthetic compounds, we discovered a potent bioactive, MAC-545496, that reverses ß-lactam resistance in the community-acquired MRSA USA300 strain. MAC-545496 could also serve as an antivirulence agent alone; it attenuates MRSA virulence in Galleria mellonella larvae. MAC-545496 inhibits biofilm formation and abrogates intracellular survival in macrophages. Mechanistic characterization revealed MAC-545496 to be a nanomolar inhibitor of GraR, a regulator that responds to cell-envelope stress and is an important virulence factor and determinant of antibiotic resistance. The small molecule discovered herein is an inhibitor of GraR function. MAC-545496 has value as a research tool to probe the GraXRS regulatory system and as an antibacterial lead series of a mechanism to combat drug-resistant Staphylococcal infections.


Assuntos
Antibacterianos/farmacologia , Ensaios de Triagem em Larga Escala/métodos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Piperidinas/farmacologia , Piridinas/farmacologia , Resistência beta-Lactâmica/efeitos dos fármacos , Animais , Biofilmes/efeitos dos fármacos , Larva/microbiologia , Lepidópteros/microbiologia , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Camundongos , Testes de Sensibilidade Microbiana , Células RAW 264.7 , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Fatores de Virulência/antagonistas & inibidores
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...