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1.
Urology ; 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38735441

RESUMO

OBJECTIVE: To provide a framework for diversifying the urologic workforce through residency recruitment by integrating principles of diversity, equity, and inclusion (DEI) into program mission and values, application review, and interview process. MATERIALS AND METHODS: For this narrative review, the Society of Women in Urology Advancing DEI in Urology Residency Recruitment Task Force identified four areas for incorporating DEI into residency recruitment: defining a residency program's mission and values, holistic application review, an objective interview process, and implementing DEI principles into a program. Using PubMed and Google Scholar, we performed a non-systematic literature search of articles from January 2014 through January 2024. Search terms included combinations of "diversity", "equity", "inclusion", "residency", "holistic review", "applications", "interviews", and "initiatives". Additional resources were identified through citations of selected articles. Based on findings from these articles, Task Force members made recommendations for best practices. RESULTS: The diversity of practicing urologists is disproportionate to that of the United States population. Emerging evidence demonstrates that DEI efforts in healthcare are associated with better outcomes and reduction in healthcare inequities. We offer strategies for residency programs to integrate DEI initiatives into their recruitment, application review, and interview process. Furthermore, we address extending DEI principles into a program's mission and culture to create an inclusive environment conducive to training and supporting individuals from unique backgrounds. CONCLUSION: It is critical to recruit and retain diverse talent into urology to improve patient care. We urge residency programs and their supporting institutions to adopt DEI principles into their recruitment efforts.

2.
Neurourol Urodyn ; 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38587244

RESUMO

INTRODUCTION: There has been increased interest in using autologous tissues since the Food and Drug Administration banned transvaginal mesh for pelvic organ prolapse in 2019. Our study aims to assess patients' perspective of functional and cosmetic impact on the fascia lata harvest site in patients undergoing fascia lata harvest for the treatment of stress urinary incontinence (SUI). METHODS: This is a prospective survey study of a retrospective cohort of patients who underwent a fascia lata pubovaginal sling between 2017 and 2022. Participants completed a survey regarding the functional and cosmetic outcomes of the harvest site. RESULTS: Seventy-two patients met the inclusion criteria. Twenty-nine patients completed the survey for a completion rate of 40.3%. For functional symptoms, 24.1% (7/29) of patients reported leg discomfort, 10.3% (3/29) reported leg weakness, 10.3% (3/29) reported a bulge, 17.2% (5/29) reported scar pain, 14.8% (4/27) reported scar numbness, and 17.2% (5/29) reported paresthesia at the scar. For cosmetic outcomes, 72.4% (21/29) reported an excellent or good scar appearance. On the PGI-I, 75.9% (22/29) reported their condition as very much better (48.3%, 14/29) or much better (27.6%, 8/29). CONCLUSIONS: The majority of patients reported being satisfied with the functional and cosmetic outcomes of their harvest site as well as satisfied with the improvement in their SUI. Less than 25% of patients report harvest site symptoms, including leg weakness, scar bulging, scar pain, scar numbness, or paresthesia in the scar. This is important in the context of appropriate preoperative discussion and counseling regarding fascia lata harvest.

3.
Urology ; 186: 162-165, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-38408492

RESUMO

An 11-year-old otherwise healthy female presented with renal colic and during computed tomography imaging evaluation, she was found to have a right distal ureteral stone with associated hydroureteronephrosis, medially deviated ureter, and 4-cm solid retroperitoneal mass. The mass was palpable on physical exam and was further categorized with magnetic resonance imaging, ultrasound, and laboratory testing. A multidisciplinary team approach, including pediatric surgery, radiology, oncology, and urology, led to the patient undergoing a right retrograde pyelogram, ureteroscopy with stent placement, and laparoscopic excision of retroperitoneal mass. Her pathology revealed lymphoid hyperplasia with histologic features of Castleman disease.


Assuntos
Hiperplasia do Linfonodo Gigante , Cólica Renal , Ureter , Cálculos Ureterais , Urologia , Humanos , Criança , Feminino , Cólica Renal/diagnóstico , Cólica Renal/etiologia , Hiperplasia do Linfonodo Gigante/complicações , Hiperplasia do Linfonodo Gigante/diagnóstico , Hiperplasia do Linfonodo Gigante/cirurgia , Ureter/cirurgia , Cálculos Ureterais/cirurgia
4.
Neurourol Urodyn ; 43(3): 595-603, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38318969

RESUMO

OBJECTIVES: Fluoroscopy has significantly improved lead placement and decreased surgical time for implantable sacral neuromodulation (SNM). There is a paucity of data regarding radiation and safety of fluoroscopy during SNM procedures. Our study aims to characterize fluoroscopy time and dose used during SNM surgery across multiple institutions and assess for predictors of increased fluoroscopy time and radiation dose. METHODS: Electronic medical records were queried for SNM procedures (Stage 1 and full implant) from 2016 to 2021 at four academic institutions. Demographic, clinical, and intraoperative data were collected, including fluoroscopy time and radiation dose in milligray (mGy). The data were entered into a centralized REDCap database. Univariate and multivariate analysis were performed to assess for predictive factors using STATA/BE 17.0. RESULTS: A total of 664 procedures were performed across four institutions. Of these, 363 (54.6%) procedures had complete fluoroscopy details recorded. Mean surgical time was 58.8 min. Of all procedures, 79.6% were performed by Female Pelvic Medicine and Reconstructive Surgery specialists. There was significant variability in fluoroscopy time and dose based on surgical specialty and institution. Most surgeons (76.4%) were considered "low volume" implanters. In a multivariate analysis, bilateral finder needle testing, surgical indication, surgeon volume, and institution significantly predicted increased fluoroscopy time and radiation dose (p < 0.05). CONCLUSIONS: There is significant variability in fluoroscopy time and radiation dose utilized during SNM procedures, with differences across institutions, surgeons, and subspecialties. Increased radiation exposure can have harmful impacts on the surgical team and patient. These findings demonstrate the need for standardized fluoroscopy use during SNM procedures.


Assuntos
Terapia por Estimulação Elétrica , Exposição à Radiação , Cirurgiões , Bexiga Urinária Hiperativa , Humanos , Feminino , Bexiga Urinária Hiperativa/terapia , Terapia por Estimulação Elétrica/métodos , Sacro , Exposição à Radiação/efeitos adversos
5.
J Chromatogr A ; 1715: 464612, 2024 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-38159404

RESUMO

The most crucial purpose of the measurement is to obtain a reliable result that reflects the actual qualitative and/or quantitative features of the tested material. The overriding goal of analytical chemistry is to obtain accurate results after compensating of various interference effects as well as non-linear calibration dependence. A new approach based on an integrated calibration method (ICM) supported by H-point standard addition method (HPSAM) has been used to improve the quality of analytical results. The proposed methodological approach was extended using the step-by-step dilution procedure, and five measurement conditions were used to eliminate multiplicative, additive, and non-linear interferences. On this basis, a set of estimations is obtained to improve the quality of the analytical results. The analytical usefulness of the proposed approach was tested on the example of the determination of three compounds from the group of bisphenols (BPs) using the chromatographic technique - HPLC-DAD (high-performance liquid chromatography with diode array detection). Compared to the reference method - fluorescence spectroscopy - the obtained results were characterized by excellent accuracy (RE=3 % in most cases). The developed methodology allowed to carry out a risk assessment on BPA, BPF, and BPS present in samples of shop receipts and canned food. Store clerks have been shown to be particularly vulnerable to PBF and BPS in receipts due to skin permeation (exposure factors were equal to 308.97 µg/g for BPF and 181.89 µg/g for BPS). Consumers should also pay close attention to the BPA found in canned food samples (the average concentration was equal to 20.61 µg/mL, and the tolerable daily intake was exceeded over 165.000 times). The analytical method and the methodological approach were evaluated using the RGB model and the AGREE approach - it was shown that the method can be successfully used for other analytical purposes (the method is White) and is environmentally friendly (Significance=0.63).


Assuntos
Compostos Benzidrílicos , Fenóis , Calibragem , Cromatografia Líquida de Alta Pressão/métodos , Fenóis/análise , Compostos Benzidrílicos/análise
6.
Urol Case Rep ; 50: 102515, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37601832

RESUMO

A 46-year-old male presented with a localized left renal mass and underwent an open radical nephrectomy via a midline incision. He recovered uneventfully and was discharged. After one month he reported persistent incisional pain; CT demonstrated heterotopic bone formation under the fascial closure. He underwent resection of calcified preperitoneal fat. Final pathology revealed benign bone tissue. He received a course of celecoxib. The patient developed recurrence of a smaller calcification. He underwent a second resection and was treated with adjuvant radiation. The patient had improvement of pain and no ossification visualized on CT imaging at 1-year follow up.

7.
Urol Oncol ; 41(12): 485.e1-485.e7, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37442741

RESUMO

INTRODUCTION: Adjuvant intravesical therapy is recommended for patients with intermediate-risk NMIBC. While intravesical gemcitabine-docetaxel (Gem/Doce) has demonstrated favorable outcomes for high-risk NMIBC, its utility in the intermediate-risk setting is not well described. We report outcomes of Gem/Doce as an adjuvant treatment for intermediate-risk NMIBC. METHODS: We retrospectively identified patients with intermediate-risk NMIBC by AUA criteria treated with Gem/Doce following TURBT between 2012 and 2022. Patients received weekly sequential intravesical instillations of 1 g gemcitabine and 37.5 mg docetaxel for 6 weeks. Monthly maintenance of 2 years was initiated if disease-free at first surveillance. The primary outcome was recurrence-free survival (RFS), assessed using the Kaplan-Meier method. RESULTS: The cohort included 77 patients with median follow-up of 26 (IQR 14-50) months. Prior to induction, 67 (87%) patients presented with Ta low-grade (LG) lesions, 3 (3.9%) with Ta high-grade (HG), 5 (6.5%) with TaLG plus focal TaHG, and 2 (2.6%) with T1LG. Thirty-three (43%) patients received previous intravesical therapy including BCG (23), mitomycin (13), and docetaxel monotherapy (12). The 2-year RFS was 71% among all patients. Treatment-naïve patients had superior RFS compared to previously treated patients (P = 0.04); 2-year estimates were 79% and 64%, respectively. Twenty-nine (38%) patients experienced adverse events; all were Grade 1 to 2 except 1 (1.3%) Grade 3 (acute oxygen desaturation). Three (3.9%) patients did not tolerate a full induction course. CONCLUSIONS: In this retrospective review of a heterogenous population of patients with intermediate-risk NMIBC, Gem/Doce was an effective and well-tolerated adjuvant therapy. Further prospective evaluation in this setting is needed.


Assuntos
Neoplasias não Músculo Invasivas da Bexiga , Neoplasias da Bexiga Urinária , Humanos , Gencitabina , Docetaxel/uso terapêutico , Desoxicitidina , Estudos Retrospectivos , Neoplasias da Bexiga Urinária/patologia , Mitomicina/uso terapêutico , Adjuvantes Imunológicos/uso terapêutico , Administração Intravesical , Vacina BCG/uso terapêutico , Invasividade Neoplásica , Recidiva Local de Neoplasia/tratamento farmacológico
8.
Top Curr Chem (Cham) ; 381(4): 16, 2023 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-37169979

RESUMO

Acetylcholine (ACh) is one of the most crucial neurotransmitters of the cholinergic system found in vertebrates and invertebrates and is responsible for many processes in living organisms. Disturbances in ACh transmission are closely related to dementia in Alzheimer's and Parkinson's disease. ACh in biological samples is most often determined using chromatographic techniques, radioenzymatic assays, enzyme-linked immunosorbent assay (ELISA), or potentiometric methods. An alternative way to detect and determine acetylcholine is applying spectroscopic techniques, due to low limits of detection and quantification, which is not possible with the methods mentioned above. In this review article, we described a detailed overview of different spectroscopic methods used to determine ACh with a collection of validation parameters as a perspective tool for routine analysis, especially in basic research on animal models on central nervous system. In addition, there is a discussion of examples of other biological materials from clinical and preclinical studies to give the whole spectrum of spectroscopic methods application. Descriptions of the developed chemical sensors, as well as the use of flow technology, were also presented. It is worth emphasizing the inclusion in the article of multi-component analysis referring to other neurotransmitters, as well as the description of the tested biological samples and extraction procedures. The motivation to use spectroscopic techniques to conduct this type of analysis and future perspectives in this field are briefly discussed.


Assuntos
Acetilcolina , Animais , Acetilcolina/fisiologia , Análise Espectral
9.
J Hazard Mater ; 448: 130871, 2023 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-36709741

RESUMO

The basic variant of the integrated calibration method (ICM), based on a combination of external calibration (EC) and standard addition method (SAM), was applied to multi-component (MC) analysis to obtain a new methodological approach to improve the quality of analytical results. The analytical performance of the proposed method was evaluated on indicated by EPA polycyclic aromatic hydrocarbons (PAHs) determination in various environmental samples (air, house dust, tap water, river water, river sediment, and snow) from the Katowice region (Poland). HPLC-FLD was used during all analyses. The main aim was to show the origin of PAHs in different places in the urban and industrialized region of Poland. MC-ICM allowed for the elimination of interference from the coelution of other substances. Several diagnostic coefficients were calculated for the results free from systematic errors and interferences. The obtained results were consistent with the chemometric analysis (PCA). The method was assessed regarding analytical usefulness using the RGB model (the color method is White) and environmental friendliness using the AGREE approach.

10.
Can J Urol ; 29(3): 11162-11169, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35691038

RESUMO

INTRODUCTION: To identify prognostic factors for overall survival (OS) in patients with malignant ureteral obstruction (MUO) from gynecologic malignancy (GM), with the goal of improving patient selection for urinary diversion. MATERIALS AND METHODS: Retrospective review of 126 patients with MUO from GM at two academic centers from 2011-2019. Factors related to OS identified by Cox regression proportional hazard model. In patients with incomplete survival data (n = 30), hospice was used as a surrogate for death. Multivariate models and receivers operating characteristics (ROC) curves were created for hemoglobin and albumin values. RESULTS: Overall median survival was 6.2 months. On univariate analysis, age at diagnosis, Charlson Comorbidity Index (CCI) ≥ 8, advanced clinical stage, ascites, pleural effusion, albumin, and hemoglobin were associated with poor OS. OS was higher for those receiving ureteral stenting as compared with no intervention. There was no survival difference based on hydronephrosis grade, stent failure (SF), or creatinine at the time of intervention. On multivariate analysis, albumin < 2.85 g/dL and hemoglobin < 9.6 g/dL were predictive of poor OS. CONCLUSIONS: OS in patients with MUO due to GM is poor. Several prognostic factors for poor survival including low serum albumin and hemoglobin were identified. Ureteral stenting was associated with improved OS compared to observation, but selection bias likely contributed to this result. Additional studies are needed to clarify this finding. These data can be utilized to counsel patients regarding outcomes after urinary diversion in the setting of MUO and perhaps avoid additional procedures in some of these patients who will not derive meaningful benefit.


Assuntos
Hidronefrose , Ureter , Obstrução Ureteral , Albuminas , Feminino , Humanos , Hidronefrose/etiologia , Prognóstico , Estudos Retrospectivos , Stents/efeitos adversos , Obstrução Ureteral/diagnóstico , Obstrução Ureteral/etiologia , Obstrução Ureteral/cirurgia
11.
Int J Mol Sci ; 22(19)2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34638911

RESUMO

Analytical methods using the fluorescence properties of bisphenols (BPA, BPF and BPS) and their complexes with ß-cyclodextrin and methyl-ß-cyclodextrin were developed. The methods were applied for the analysis of thermal paper and canned food. Their performance was compared with a standard HPLC approach with a diode array and fluorescence detections. For comparison purposes, basic validation parameters (linear range, limit of detection, sensitivity, precision) were evaluated. It was concluded the developed methods facilitate fast and cost-effective determination of three bisphenol species in liquid samples, similar to the HPLC performance. They are also environmentally friendly. BPA, BPF and BPS can be routinely determined with the presented approach.


Assuntos
Compostos Benzidrílicos/análise , Cromatografia/métodos , Fenóis/análise , Espectrometria de Fluorescência/métodos , Cromatografia Líquida de Alta Pressão/métodos , Alimentos em Conserva/análise , Humanos , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem/métodos
12.
Int J Risk Saf Med ; 32(4): 321-329, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34366299

RESUMO

BACKGROUND: Post-SSRI sexual dysfunction (PSSD) is an underrecognized and poorly understood medical condition characterized by sexual dysfunction that persists despite SSRI discontinuation. OBJECTIVE: We conducted a survey of individuals with PSSD to better characterize this condition and its impact on various quality of life concerns. METHODS: Surveys were distributed to an online support group for individuals with PSSD. Surveys assessed medications suspected of causing PSSD and symptoms experienced during and after treatment. Respondents reported the trajectory of their condition, the efficacy of different treatments, and the impact of PSSD on their quality of life. RESULTS: 239 survey responses were included in this study. A majority of respondents had a history of SSRI use (92%) compared to only SNRI or atypical antidepressant use (8%). The overall severity of symptoms improved for 45% and worsened or remained the same for 37% of respondents after discontinuing treatment with serotonin reuptake inhibitors. Only 12% of respondents reported being counseled regarding potential sexual dysfunction while taking antidepressants. The majority rated the effect of PSSD on their quality of life as extremely negative (59%) or very negative (23%). CONCLUSION: PSSD can have an overwhelmingly negative impact on quality of life. Currently, it is unclear why certain individuals develop PSSD and there are no definitive treatments for this condition. Further research of PSSD and greater awareness of this condition is needed among prescribers of serotonin reuptake inhibitors to improve patient care.


Assuntos
Qualidade de Vida , Disfunções Sexuais Fisiológicas , Antidepressivos/efeitos adversos , Humanos , Inibidores Seletivos de Recaptação de Serotonina/efeitos adversos , Disfunções Sexuais Fisiológicas/induzido quimicamente , Disfunções Sexuais Fisiológicas/tratamento farmacológico , Inquéritos e Questionários
14.
Pediatr Dermatol ; 38(2): 547-549, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33210364

RESUMO

When children present with features of bed bug bites, many parents are reluctant to accept the diagnosis. Furthermore, standard methods to detect arthropods in or around one's home can be expensive, time-consuming, and frustrating. We developed a simple, inexpensive way to provide evidence that the lesions are in fact due to arthropod bites. The Modified Onesie Biting Bug Assessment (MOBBA) suit utilizes simple alterations to a full-body onesie-type footed pajama, exposing some body surfaces to insect predators while protecting other areas.


Assuntos
Artrópodes , Percevejos-de-Cama , Traumatismos dos Dedos , Mordeduras e Picadas de Insetos , Lesões dos Tecidos Moles , Animais , Criança , Humanos , Mordeduras e Picadas de Insetos/diagnóstico
16.
Eur Urol Open Sci ; 22: 17-22, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34337474

RESUMO

BACKGROUND: Retzius-sparing robotic-assisted radical prostatectomy (RS-RARP) has improved urinary function compared with standard robotic-assisted radical prostatectomy (S-RARP). As RS-RARP spares the dorsal vascular complex, pelvic fascia, and anterior abdominal fascia, it may also lower the incidence of "neglected" postprostatectomy sequelae such as penile shortening, Peyronie's disease, and inguinal hernias. OBJECTIVE: To determine whether there are patient-perceived differences in penile shortening, Peyronie's disease, and inguinal hernia rates among men undergoing RS-RARP versus S-RARP. DESIGN SETTING AND PARTICIPANTS: Researchers uninvolved in clinical care and blinded to surgical approach surveyed 60 RS-RARP versus 57 S-RARP men with validated patient-reported items to assess penile shortening, Peyronie's disease, and inguinal hernia sequelae following surgery. INTERVENTION: RS-RARP versus S-RARP. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Univariate differences between the two cohorts were analyzed using Student t test. Logistic regression was used to analyze variables associated with postoperative penile shortening. Cox proportional hazards models were used to assess the risk of developing Peyronie's disease and inguinal hernia postoperatively. RESULTS AND LIMITATIONS: RS-RARP was associated with less patient-reported penile shortening (41.7% vs 64.9%, p = 0.012), Peyronie's disease (0% vs 8.7%, p = 0.020), and inguinal hernia (0.0% vs 13.0%, p = 0.004). In adjusted analyses, RS-RARP (odds ratio [OR] 0.24, 95% confidence interval [CI] 0.09-0.63, p = 0.004) was associated with lower odds of penile shortening, while a higher body mass index was associated with increased odds of penile shortening (OR 1.13, 95% CI 1.01-1.26, p = 0.037). RS-RARP was not associated with a decreased risk of Peyronie's disease on Cox proportion hazard model; however, these models are limited due to a limited number of events in our cohort. Limitations include retrospective design, patient-reported outcomes, and small cohorts. CONCLUSIONS: RS-RARP is associated with less patient-reported penile shortening and may decrease the risk of Peyronie's disease and postoperative inguinal hernia development. These new findings add to research, showing improved urinary continence and quality of life following RS-RARP; however, a prospective study is needed to validate these findings. PATIENT SUMMARY: Retzius-sparing robotic-assisted radical prostatectomy (RS-RARP) is an evolving surgical technique for prostate cancer treatment, which has shown improved postoperative urinary control compared with the standard technique, likely due to preservation of natural pelvic anatomy. Our findings suggest that the preservation of normal pelvic anatomy during RS-RARP may also reduce the risk of postprostatectomy penile shortening, Peyronie's disease, and inguinal hernia.

17.
Talanta ; 138: 64-70, 2015 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-25863373

RESUMO

The performance of the recently proposed excitation-emission fluorescence method was compared to the method using infrared measurements for the evaluation of the antioxidant properties of intact samples and extracts that had been obtained from tomato pastes. The oxygen radical absorbance capacity assay (ORAC) was applied in order to estimate the antioxidant capacity of the extracts, while the Folin-Ciocalteu reagent was adopted for the evaluation of the total phenolic content. The optimal extraction conditions for tomato pastes (three minutes of sonication under 80°C) were determined using the central composite design. Chemometric models such as the partial least squares regression and its N-way variant were further constructed in order to predict the antioxidant capacity or total phenolic content of the samples using either the IR or fluorescence spectra. The prediction errors that were obtained for the total antioxidant content were evaluated as the Trolox equivalents from the ORAC assay and were found to be equal to 2.011 (14.21%) for the fluorescence and 2.426 (17.15%) for the IR spectra, respectively. The prediction errors of the total phenolic content expressed as gallic acid equivalents were 0.067 (10.78%) for the fluorescence and 0.033 (5.36%) for the IR spectra, which were used as independent variables in the regression models.


Assuntos
Antioxidantes/análise , Fenóis/análise , Solanum lycopersicum/química , Espectrometria de Fluorescência/métodos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Interações Hidrofóbicas e Hidrofílicas , Espécies Reativas de Oxigênio/metabolismo
18.
Anal Bioanal Chem ; 407(4): 1159-70, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25407430

RESUMO

In the countries of the European Community, diesel fuel samples are spiked with Solvent Yellow 124 and either Solvent Red 19 or Solvent Red 164. Their presence at a given concentration indicates the specific tax rate and determines the usage of fuel. The removal of these so-called excise duty components, which is known as fuel "laundering", is an illegal action that causes a substantial loss in a government's budget. The aim of our study was to prove that genuine diesel fuel samples and their counterfeit variants (obtained from a simulated sorption process) can be differentiated by using their gas chromatographic fingerprints that are registered with a flame ionization detector. To achieve this aim, a discriminant partial least squares analysis, PLS-DA, for the genuine and counterfeit oil fingerprints after a baseline correction and the alignment of peaks was constructed and validated. Uninformative variables elimination (UVE), variable importance in projection (VIP), and selectivity ratio (SR), which were coupled with a bootstrap procedure, were adapted in PLS-DA in order to limit the possibility of model overfitting. Several major chemical components within the regions that are relevant to the discriminant problem were suggested as being the most influential. We also found that the bootstrap variants of UVE-PLS-DA and SR-PLS-DA have excellent predictive abilities for a limited number of gas chromatographic features, 14 and 16, respectively. This conclusion was also supported by the unitary values that were obtained for the area under the receiver operating curve (AUC) independently for the model and test sets.

19.
J Chromatogr A ; 1366: 101-9, 2014 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-25283576

RESUMO

Models to predict the total antioxidant capacity (TAC) of rooibos tea infusions from their chromatographic fingerprints and peak table data (content of individual phenolic compounds), obtained using HPLC with diode array detection, were developed in order to identify potential antioxidant markers. Peak table data included the content of 12 compounds, namely phenylpyruvic acid-2-O-glucoside, aspalathin, nothofagin, isoorientin, orientin, ferulic acid, quercetin-3-O-robinobioside, vitexin, hyperoside, rutin, isovitexin and isoquercitrin. The TAC values, measured using the oxygen radical absorbance capacity (ORAC) and DPPH radical scavenging assays, could be predicted from the peak table data or the chromatographic fingerprints (prediction errors 9-12%) using partial least squares (PLS) regression. Prediction models created from samples of only two production years could additionally be used to predict the TAC of samples from another production year (prediction errors<13%) indicating the robustness of the models in a quality control environment. Furthermore, the uninformative variable elimination (UVE)-PLS method was used to identify potential antioxidant markers for rooibos infusions. All individual phenolic compounds that were quantified were selected as informative variables, except vitexin, while UVE-PLS models developed from chromatographic fingerprints indicated additional antioxidant markers, namely (S)-eriodictyol-6-C-glucoside, (R)-eriodictyol-6-C-glucoside, aspalalinin and two unidentified compounds. The potential antioxidant markers should be validated prior to use in quality control of rooibos tea.


Assuntos
Antioxidantes/análise , Aspalathus/química , Bebidas/análise , Modelos Teóricos , Fenóis/análise , Extratos Vegetais/química , Cromatografia Líquida de Alta Pressão
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