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1.
Breast ; 72: 103591, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37871527

RESUMO

Inflammatory breast cancer (IBC) poses an ongoing challenge as rates of disease recurrence and mortality remain high compared to stage-matched controls. However, frontline therapy has evolved through the years, including the widespread use of neoadjuvant chemotherapy (NAC) given the prognostic importance of pathologic complete response (pCR). Due to these sweeping changes, we need new data to assess current recurrence and survival outcomes for locally advanced IBC in the context of matched non-inflammatory controls. We conducted a retrospective analysis of institutional IBC data from 2010 to 2016 with the primary objective of comparing overall survival (OS), relapse-free survival (RFS), and distant relapse-free survival (DRFS). We matched IBC patients to non-inflammatory controls based on age, receptor status, tumor grade, clinical stage, and receipt of prior NAC. Secondary objectives included assessing pCR rates and identifying prognostic factors. Among NAC recipients, we observed similar pCR rates (47.6 % vs. 49.4 %, p = 0.88) between IBC (n = 84) and matched non-IBC (n = 81) cohorts. However, we noted a significant worsening of OS (p = 0.0001), RFS (p = 0.0001), and DRFS (p = 0.001) in the IBC group. Specifically, 5-year OS in the IBC cohort was 58.9 % vs. 86.7 % for matched controls (p = 0.0003). Older age was a weak negative predictor for OS (HR 1.03, p = 0.001) and RFS (HR 1.02, p = 0.01). For DRFS, older age was also a weak negative predictor (HR 1.02, p = 0.02), whereas the use of NAC was a positive predictor (HR 0.47, p = 0.02). Despite no clear difference in pCR, survival outcomes remain poor for IBC compared to matched non-inflammatory controls.


Assuntos
Neoplasias da Mama , Neoplasias Inflamatórias Mamárias , Humanos , Feminino , Terapia Neoadjuvante , Intervalo Livre de Doença , Estudos Retrospectivos , Neoplasias da Mama/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Quimioterapia Adjuvante , Recidiva Local de Neoplasia/tratamento farmacológico , Prognóstico
2.
Oncol Ther ; 11(3): 361-374, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37354381

RESUMO

INTRODUCTION: The immunomodulatory impact of corticosteroids and concurrent chemotherapy is poorly understood within triple-negative breast cancer (TNBC). On a biochemical level, steroids have been linked to the signaling of chemotherapy-resistant pathways. However, on a clinical level, steroids play an essential role in chemotherapy tolerance through the prevention of chemotherapy-induced nausea and vomiting (CINV) and hypersensitivity reactions. Given these conflicting roles, we wanted to evaluate this interplay more rigorously in the context of early-stage TNBC. METHODS: We performed a retrospective analysis of patients with operable TNBC who received neoadjuvant chemotherapy (NAC) between January 2012 and November 2018, with the primary goal of examining the dose-dependent relationship between pathological complete response (pCR) rates and corticosteroid use. Secondary endpoints included the impact of steroid dosing on overall survival (OS) and recurrence-free survival (RFS), along with a breakdown in pCR rates based on steroid doses provided during each chemotherapy phase. Further adjusted analyses were performed based on patient age, diabetic status, and anatomical stage. Finally, we explored the relationship between tumor-infiltrating lymphocytes (TILs) seen on tissue samples at baseline and dexamethasone doses in terms of pCR rates. RESULTS: In total, of the 174 patients screened within this study period, 116 met full eligibility criteria. Of these eligible patients, all were female, with a median age of 51.5 years (27.0 to 74.0) and a mean body mass index (BMI) of 29.7 [standard deviation (SD) 7.04]. The majority were nondiabetic (80.2%). For cancer stage, 69.8% (n = 81) had stage 2 breast cancer. We found no statistically significant association between pCR rates and dexamethasone use, both in terms of the total dose (p = 0.55) and mean dose per NAC cycle (p = 0.74). Similarly, no difference was noted when adjusting for diabetic status, metformin use, or age at diagnosis, regardless of the total steroid dose provided (p = 0.72) or mean dose per cycle (p = 0.49). No meaningful changes to pCR rate were seen with higher mean or higher total steroid doses during the paclitaxel (T) phase (adjusted p = 0.16 and p = 0.76, respectively) or doxorubicin and cyclophosphamide (AC) phase (adjusted p = 0.83 and p = 0.77, respectively). Furthermore, we found no clinically significant association between dexamethasone dose and either RFS (p = 0.45) or OS (p = 0.89). Of the 56 patients who had available pre-treatment biopsy tissue samples, 27 achieved pCR, with higher TILs at baseline being associated with higher pCR rates, regardless of the mean dexamethasone dose used. CONCLUSION: Our findings demonstrate that dexamethasone has no clinically significant impact on pCR, RFS, or OS when given concurrently with NAC in patients with curative TNBC, regardless of diabetic status.

3.
Complement Ther Med ; 70: 102870, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35952958

RESUMO

BACKGROUND: To assess Hong Kong medical students' knowledge, attitudes and beliefs on cannabis and its future legal reform. METHODS: A cross-sectional anonymous online survey were sent from 1st December 2018 to 31st August 2020 to all medical students from the Li Ka Shing Faculty of Medicine, the University of Hong Kong (HKU). RESULTS: 187 students (13.6 %) responded the survey. Overall, students perceived cannabis possessed significant physical and mental health risks, but they were more neutral to its physical and mental benefits. They also supported legalizing cannabis more so for medical use than recreational use. Females perceived higher risks than males. Those who used cannabis before were more acceptable to recommend cannabis as medical treatments, perceived cannabis use with greater benefits and less risks, and were more likely to support legal reform for cannabis in Hong Kong than their counterparts. Students were also more likely to recommend medical cannabis than non-licensed cannabis to patients if they were legally available. CONCLUSION: Medical students in Hong Kong supported legalization of cannabis for medical use despite perceiving significant risks from cannabis use. Future research should investigate public acceptance on medical cannabis in Hong Kong and other Asian countries.


Assuntos
Cannabis , Maconha Medicinal , Estudantes de Medicina , Estudos Transversais , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Hong Kong , Humanos , Masculino , Inquéritos e Questionários
4.
J Hematol Oncol ; 15(1): 118, 2022 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-36031601

RESUMO

Immune checkpoint inhibitors targeting programmed cell death protein 1, programmed death-ligand 1, and cytotoxic T-lymphocyte-associated protein 4 provide deep and durable treatment responses which have revolutionized oncology. However, despite over 40% of cancer patients being eligible to receive immunotherapy, only 12% of patients gain benefit. A key to understanding what differentiates treatment response from non-response is better defining the role of the innate immune system in anti-tumor immunity and immune tolerance. Teleologically, myeloid cells, including macrophages, dendritic cells, monocytes, and neutrophils, initiate a response to invading pathogens and tissue repair after pathogen clearance is successfully accomplished. However, in the tumor microenvironment (TME), these innate cells are hijacked by the tumor cells and are imprinted to furthering tumor propagation and dissemination. Major advancements have been made in the field, especially related to the heterogeneity of myeloid cells and their function in the TME at the single cell level, a topic that has been highlighted by several recent international meetings including the 2021 China Cancer Immunotherapy workshop in Beijing. Here, we provide an up-to-date summary of the mechanisms by which major myeloid cells in the TME facilitate immunosuppression, enable tumor growth, foster tumor plasticity, and confer therapeutic resistance. We discuss ongoing strategies targeting the myeloid compartment in the preclinical and clinical settings which include: (1) altering myeloid cell composition within the TME; (2) functional blockade of immune-suppressive myeloid cells; (3) reprogramming myeloid cells to acquire pro-inflammatory properties; (4) modulating myeloid cells via cytokines; (5) myeloid cell therapies; and (6) emerging targets such as Siglec-15, TREM2, MARCO, LILRB2, and CLEVER-1. There is a significant promise that myeloid cell-based immunotherapy will help advance immuno-oncology in years to come.


Assuntos
Imunoterapia , Neoplasias , Humanos , Terapia de Imunossupressão , Células Mieloides , Microambiente Tumoral
5.
Expert Rev Anticancer Ther ; 22(5): 505-522, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35389302

RESUMO

INTRODUCTION: Since the advent of anti-HER2 therapies, evidence surrounding adjuvant treatment of small (T1mic, T1a, and T1b), node-negative, HER2-positive breast cancer (HER2+ BC) has remained limited. Practices vary widely between institutions with little known regarding the added benefit of systemic therapy, including cytotoxic chemotherapy and HER2-directed treatments. Our group has set out to perform an extensive review of available literature on this topic. AREAS COVERED: In this review, we examined HER2 biology, anti-HER therapies, outcome definitions, and available prospective and retrospective data surrounding the use of adjuvant therapy in those with small, node-negative, HER2+ BC. For outcomes, we primarily explored breast cancer-specific survival (BCSS), invasive disease-free survival (iDFS), and overall survival (OS). We also investigated the incidence of adverse events with a particular focus on symptomatic and asymptomatic declines in ejection fraction. EXPERT OPINION: Retrospective data will likely be the main driver for future treatment decisions. Given what we know, high-risk T1b and T1c subgroups derive measurable added benefit from HER2-guided combination therapies but it's not clear whether these benefits outweigh known risks associated with this combination therapy. For tumors ≤0.5 cm (T1mic and T1a), treatment remains highly controversial with limited evidence available through retrospective analysis that suggest over-treatment may be occurring.


Assuntos
Neoplasias da Mama , Neoplasias da Mama/patologia , Quimioterapia Adjuvante , Feminino , Humanos , Estadiamento de Neoplasias , Estudos Prospectivos , Receptor ErbB-2 , Estudos Retrospectivos
6.
BMC Urol ; 21(1): 51, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33794867

RESUMO

BACKGROUND: Severe hypercalcemia is often associated with uncontrolled malignancy through several mechanisms. However, calcitriol-mediated hypercalcemia is a rare etiology for advanced solid tumors. CASE PRESENTATION: We report a case of calcitriol-mediated hypercalcemia secondary to immune checkpoint inhibition in a responder with metastatic clear cell renal cell carcinoma (ccRCC). In this case, a 68 year old male with metastatic ccRCC to the liver within 4 months of right radical nephrectomy went on to develop hypercalcemia (12.8 mg/dL) shortly following 2 cycles of nivolumab and ipilimumab. Additional testing showed an elevated calcitriol level (142 pg/mL), low parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP) levels, and a normal 25-hydroxyvitamin D level. FDG-PET imaging showed hypermetabolic mediastinal, hilar, and intra-abdominal lymphadenopathy, however the subsequent lymph node biopsy only showed reactive lymphoid cells without malignancy or granuloma. The hypercalcemia was resistant to initial therapy with calcitonin, hydration, and zoledronic acid but quickly responded to high-dose prednisone (1 mg/kg), followed by normalization of calcitriol levels. The patient was rechallenged with nivolumab and ipilimumab which provided a partial response after 4 cycles. He was maintained on low dose prednisone (10 mg daily) leading to a sustained resolution of his hypercalcemia. CONCLUSION: This case suggests calcitriol-mediated hypercalcemia as a novel immune-related adverse event.


Assuntos
Antineoplásicos Imunológicos/efeitos adversos , Calcitriol/metabolismo , Hipercalcemia/induzido quimicamente , Ipilimumab/efeitos adversos , Nivolumabe/efeitos adversos , Idoso , Humanos , Masculino
8.
AIDS Res Hum Retroviruses ; 36(6): 459-466, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31931589

RESUMO

Efavirenz (EFV) is one of the most commonly prescribed antiretroviral therapy (ART) medications for human immunodeficiency virus-infected adults because of its favorable pharmacokinetic profile and well-documented efficacy. Nonetheless, neuropsychiatric adverse events (AE) occur in almost half of the EFV users and it is the main reason for treatment discontinuation. To identify the sociodemographic characteristics and reported neuropsychiatric side effects that placed EFV users at an increased risk of discontinuation in a multi-ethnic sample in the United Kingdom. A retrospective medical records analysis of patients prescribed EFV-containing ART in an outpatient sexual health clinic between 2010 and 2016. One hundred forty-nine medical records were reviewed. Fifty-five patients discontinued EFV within the study period. About 55.7% of patients suffered from at least one neuropsychiatric AE, the most commonly recorded symptoms were depression, vivid dreams, dizziness, and sleep disturbance. There was an inverse relationship between number of AE and EFV continuation [adjust odds ratio (OR) = 0.12; confidence interval (95% CI) = 0.03-0.44, p < .05]. Furthermore, neuropsychiatric symptoms, including depression (adjust OR = 3.01; 95% CI = 1.30-6.96, p < .05), sleep disturbance (adjust OR = 3.00; 95% CI = 1.10-8.19, p < .05), and vivid dreams (adjust OR = 2.51; 95% CI = 1.05-6.00, p < .05), were independent predictors of EFV discontinuation. The findings revealed that patients who did not experience any neuropsychiatric side effects were eight times more likely to stay on an EFV-containing regimen than those who suffered from more than three symptoms. Additionally, patients who experienced depression or sleep disturbance were at threefold elevated risk of discontinuing an EFV-based regimen. The implications for clinical practice are discussed.


Assuntos
Alcinos/efeitos adversos , Fármacos Anti-HIV/efeitos adversos , Benzoxazinas/efeitos adversos , Ciclopropanos/efeitos adversos , Infecções por HIV/tratamento farmacológico , Transtornos Mentais/induzido quimicamente , Adulto , Idoso , Alcinos/uso terapêutico , Fármacos Anti-HIV/uso terapêutico , Benzoxazinas/uso terapêutico , Ciclopropanos/uso terapêutico , Etnicidade , Feminino , Infecções por HIV/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Cooperação e Adesão ao Tratamento/estatística & dados numéricos , Reino Unido/epidemiologia , Suspensão de Tratamento , Adulto Jovem
9.
Med Oncol ; 36(11): 93, 2019 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-31595355

RESUMO

In patients with locally advanced human papillomavirus (HPV)-unrelated head and neck squamous-cell carcinoma (HNSCC), cisplatin and radiation therapy (CisRT) resulted in a local-regional recurrence (LRR) rate of 35%, progression-free survival (PFS) of 49%, and overall survival (OS) of 60%. We, and others, showed that nab-paclitaxel is an active agent in metastatic and locally advanced HNSCC. The aim of this report was to assess the efficacy of nab-paclitaxel-based induction chemotherapy and CisRT in HPV-unrelated HNSCC. We performed a retrospective single-institution analysis of patients treated with nab-paclitaxel-based chemotherapy and CisRT. Key inclusion criteria included stage III-IV HPV-unrelated HNSCC. Induction chemotherapy included nab-paclitaxel and cisplatin (AP), AP + 5-fluorouracil (APF), or APF + Cetuximab (APF-C). Endpoints included LRR, overall relapse, PFS, and OS. Thirty-eight patients were the subject of this analysis. Patient characteristics included median age 59 years (IQR: 54-64) and smoking history in 36 patients (95%). Primary tumor sites included larynx/hypopharynx (27), p16 negative oropharynx (10), and oral cavity (1). Most patients had bulky disease: 82% T3-4 (n = 31) and 74% N2b-3 (n = 28). Median follow-up was 44 months (IQR: 23-59). The three-year LRR rate was 16% (95% confidence interval [CI] 7-34) and the overall relapse rate was 22% (95% CI 11-41). The three-year PFS was 64% (95% CI 46-77) and OS was 72% (95% CI 54-84). Among patients with HPV-unrelated HNSCC, nab-paclitaxel-based induction chemotherapy and CisRT resulted in a lower-than-expected rate of LRR and more favorable PFS and OS compared to historical results with CisRT.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Cisplatino/uso terapêutico , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/radioterapia , Carcinoma de Células Escamosas de Cabeça e Pescoço/tratamento farmacológico , Carcinoma de Células Escamosas de Cabeça e Pescoço/radioterapia , Adulto , Idoso , Albuminas/administração & dosagem , Quimiorradioterapia , Feminino , Neoplasias de Cabeça e Pescoço/patologia , Neoplasias de Cabeça e Pescoço/virologia , Humanos , Quimioterapia de Indução , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Paclitaxel/administração & dosagem , Infecções por Papillomavirus/patologia , Estudos Retrospectivos , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Carcinoma de Células Escamosas de Cabeça e Pescoço/virologia
10.
Eur Arch Otorhinolaryngol ; 274(9): 3437-3442, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28616836

RESUMO

The objective of this manuscript is to review a single institution's experience with superficial or total parotidectomy in outpatient and observation/inpatient groups. All patients who underwent superficial or total parotidectomy between 2009 and 2015 were identified. Patients were excluded if they had undergone concurrent surgery such as neck dissection, had prior radiation treatment or surgery at the operative site. Main outcomes were perioperative complications in both groups. 215 consecutive patients were included in the study, 116 (54%) patients in the inpatient group and 99 (46%) in the outpatient group. Aside from a higher observed rate of cardiac disease in the outpatient group (24.2 vs. 11.2%, p = 0.014) and larger mean body mass index (BMI) in the inpatient group (32.448 vs. 30.034, p = 0.017), there were no significant differences for age, sex or smoking status. Average operative time differed between groups with 2 h 42 min for inpatients and 2 h 18 min for outpatients (p < 0.001). There were 26 complications in the inpatient group (22.4%, including two hematomas) and 8 in the outpatient group (8.1%). The rate of seroma/sialocele formation was significantly higher in the inpatient group at 15.5% (n = 18) compared with the outpatient group at 3% (n = 3, p = 0.001). Our study shows that parotidectomy, superficial or total, was performed safely as an outpatient procedure without significant increase in complications when compared to patients observed for at least one night after surgery.


Assuntos
Procedimentos Cirúrgicos Ambulatórios/métodos , Pacientes Internados , Complicações Intraoperatórias/epidemiologia , Observação/métodos , Procedimentos Cirúrgicos Otorrinolaringológicos/métodos , Neoplasias Parotídeas/cirurgia , Complicações Pós-Operatórias/epidemiologia , Adulto , Idoso , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Pacientes Ambulatoriais , Glândula Parótida/fisiologia , Glândula Parótida/cirurgia , Neoplasias Parotídeas/diagnóstico , Estados Unidos/epidemiologia
12.
Cell Rep ; 15(6): 1175-89, 2016 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-27134167

RESUMO

Like normal stem cells, tumor-initiating cells (T-ICs) are regulated extrinsically within the tumor microenvironment. Because HCC develops primarily in the context of cirrhosis, in which there is an enrichment of activated fibroblasts, we hypothesized that cancer-associated fibroblasts (CAFs) would regulate liver T-ICs. We found that the presence of α-SMA(+) CAFs correlates with poor clinical outcome. CAF-derived HGF regulates liver T-ICs via activation of FRA1 in an Erk1,2-dependent manner. Further functional analysis identifies HEY1 as a direct downstream effector of FRA1. Using the STAM NASH-HCC mouse model, we find that HGF-induced FRA1 activation is associated with the fibrosis-dependent development of HCC. Thus, targeting the CAF-derived, HGF-mediated c-Met/FRA1/HEY1 cascade may be a therapeutic strategy for the treatment of HCC.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Fibroblastos Associados a Câncer/patologia , Carcinoma Hepatocelular/patologia , Proteínas de Ciclo Celular/metabolismo , Neoplasias Hepáticas/patologia , Células-Tronco Neoplásicas/patologia , Proteínas Proto-Oncogênicas c-fos/metabolismo , Proteínas Proto-Oncogênicas c-met/metabolismo , Transdução de Sinais , Animais , Biomarcadores Tumorais/metabolismo , Fibroblastos Associados a Câncer/efeitos dos fármacos , Fibroblastos Associados a Câncer/metabolismo , Carcinogênese/metabolismo , Carcinogênese/patologia , Carcinoma Hepatocelular/genética , Linhagem Celular Tumoral , Separação Celular , Meios de Cultivo Condicionados/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Fator de Crescimento de Hepatócito/farmacologia , Humanos , Neoplasias Hepáticas/genética , Camundongos SCID , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Proteínas Proto-Oncogênicas c-fos/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transdução de Sinais/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genética
13.
J Am Coll Surg ; 222(2): 159-65, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26705900

RESUMO

BACKGROUND: Abdominal wall reconstruction for complex ventral and incisional hernias is associated with significant complications. Commonly, the peritoneal cavity is opened and adhesiolysis is performed with the potential for enterotomy. A totally extraperitoneal (TE) approach to abdominal wall reconstruction is feasible in many ventral hernia repairs and can reduce visceral injuries without impacting other outcomes. This study compares outcomes after retro-rectus ventral hernia repairs with TE and transabdominal (TA) preperitoneal approaches. STUDY DESIGN: An IRB-approved review of a prospective hernia database was performed for all ventral hernia repairs between 2009 and 2013. Preoperative patient characteristics, including demographics and comorbidities; operative variables, including surgical technique, operative duration, type/size/location of mesh, concomitant procedures, and incidence of inadvertent injury; and patient outcomes in terms of length of stay, wound and nonwound complications, and readmissions or returns to the operating room were obtained. Groups were compared using t-tests, Mann-Whitney U tests, chi-square tests, and Fisher's exact tests as appropriate. Significance was set at p < .05. RESULTS: One hundred and seventy-five complex abdominal wall reconstructions were performed between 2009 and 2013. Of those, 85 patients underwent hernia repair for CDC grade 1 hernias with retro-rectus mesh placement performed (n = 45 TA, n = 40 TE). Groups did not differ in age, BMI, sex, smoking status, hernia defect size, history of COPD, asthma, hypertension, cancer, or renal failure. More TA patients had diabetes (36% vs. 13%; p = 0.02) and previous hernia repair (73% vs. 45%; p = 0.01) than TE patients. Mesh size was larger in the TE group (625 ± 234 cm(2) vs. 424 ± 214 cm(2); p < .001). There was no difference in enterotomy between TA and TE groups (0% vs. 2%; p = 1.0). However, there was a reduced operative time with TE (170 ± 49 minutes vs. 212 ± 49 minutes; p < .001). CONCLUSIONS: Abdominal wall reconstruction can be performed safely in a TE fashion. The extraperitoneal approach results in shorter operative duration, but had similar complications when compared with TA preperitoneal approach.


Assuntos
Parede Abdominal/cirurgia , Técnicas de Fechamento de Ferimentos Abdominais , Hérnia Ventral/cirurgia , Herniorrafia/métodos , Adulto , Idoso , Feminino , Herniorrafia/efeitos adversos , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Duração da Cirurgia , Estudos Retrospectivos , Telas Cirúrgicas , Resultado do Tratamento
14.
Anal Chim Acta ; 792: 110-4, 2013 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-23910975

RESUMO

Poly (N-isopropylacrylamide)-co-acrylic acid (pNIPAm-co-AAc) microgels were "painted" on the Au electrode of a quartz crystal microbalance (QCM). Another Au layer (overlayer) was subsequently deposited on the microgel layer. This structure is known as a microgel-based etalon. These devices have been shown to exhibit optical properties (i.e., color) that depend on solution pH and temperature, among other things. Previously, we measured QCM frequency shifts that are a result of solution pH changes; the frequency shifts are a direct result of the pH dependent solvation state of the microgels that make up the etalon. In fact, the shifts observed for the etalons were much greater in magnitude than just a microgel layer immobilized on the QCM crystal without the Au overlayer. We reasoned that the Au overlayer lead to an enhancement of the observed frequency change due to its mass. In this submission we investigate how the Au overlayer thickness (mass) affects the observed sensitivity to solution pH. We found that the change in QCM resonant frequency depended dramatically on the mass of the Au overlayer.

15.
Proc Natl Acad Sci U S A ; 110(27): E2510-7, 2013 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-23776209

RESUMO

A cell-based phenotypic screen for inhibitors of biofilm formation in mycobacteria identified the small molecule TCA1, which has bactericidal activity against both drug-susceptible and -resistant Mycobacterium tuberculosis (Mtb) and sterilizes Mtb in vitro combined with rifampicin or isoniazid. In addition, TCA1 has bactericidal activity against nonreplicating Mtb in vitro and is efficacious in acute and chronic Mtb infection mouse models both alone and combined with rifampicin or isoniazid. Transcriptional analysis revealed that TCA1 down-regulates genes known to be involved in Mtb persistence. Genetic and affinity-based methods identified decaprenyl-phosphoryl-ß-D-ribofuranose oxidoreductase DprE1 and MoeW, enzymes involved in cell wall and molybdenum cofactor biosynthesis, respectively, as targets responsible for the activity of TCA1. These in vitro and in vivo results indicate that this compound functions by a unique mechanism and suggest that TCA1 may lead to the development of a class of antituberculosis agents.


Assuntos
Antituberculosos/farmacologia , Benzotiazóis/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Tiofenos/farmacologia , Tuberculose Pulmonar/tratamento farmacológico , Oxirredutases do Álcool , Sequência de Aminoácidos , Animais , Antituberculosos/administração & dosagem , Antituberculosos/química , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Benzotiazóis/administração & dosagem , Benzotiazóis/química , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Carboidratos Epimerases/antagonistas & inibidores , Carboidratos Epimerases/química , Carboidratos Epimerases/genética , Farmacorresistência Bacteriana , Feminino , Genes Bacterianos , Ensaios de Triagem em Larga Escala , Isoniazida/administração & dosagem , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Mycobacterium tuberculosis/enzimologia , Mycobacterium tuberculosis/genética , Oxirredutases/antagonistas & inibidores , Oxirredutases/química , Oxirredutases/genética , Rifampina/administração & dosagem , Tiofenos/administração & dosagem , Tiofenos/química , Tuberculose Pulmonar/microbiologia
16.
Anal Chim Acta ; 739: 83-8, 2012 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-22819053

RESUMO

Poly (N-isopropylacrylamide)-co-acrylic acid (pNIPAm-co-AAc) microgel-based etalons have been shown to have visible color and unique spectral properties, which both depend on solution temperature and pH. In this investigation, pNIPAm-co-AAc microgel-based etalons were fabricated on the Au electrode of a quartz crystal microbalance (QCM), and the resonant frequency of the QCM monitored as a function of temperature, at pH 3.0. Furthermore, the resonant frequency at either pH 3.0 or 7.0 was monitored while keeping the solution temperature constant at various temperatures. In all cases, when the solution temperature was below the collapse transition for the microgels (∼32°C), the resonant frequency at pH 3.0 was lower than at pH 7.0, which we attribute to the film transitioning from a deswollen to swollen state, respectively. It was observed that the magnitude of the resonant frequency change increased as the solution temperature approached the collapse temperature for the microgels. The overall sensitivity to pH was determined to be 1.3×10(-8)M [H(+)]Hz(-1) and a theoretical detection limit of 390nM was obtained. This sensitivity will be exploited further for future biosensing applications.

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