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1.
Oncol Res Treat ; : 1-7, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38565096

RESUMO

INTRODUCTION: Nasopharyngeal carcinoma (NPC) accounts for 0.01% of all carcinomas, and 70% of patients have locally advanced disease with a poor prognosis. The mainstay therapy is chemoradiotherapy (CRT), and concurrent administration of platinum-based agents and irradiation provides high local control rates. However, induction (neoadjuvant) chemotherapy (ICT) prior to CRT is recommended for large tumors with a high tumor burden at the category 1 level. For ICT, platinum-based doublet or triplet combination regimens are recommended. Selected patients with a high tumor burden at the time of diagnosis who did not receive ICT before CRT were given adjuvant (consolidation) therapy after CRT. This multicenter study aimed to share our experience in treatment of NPC and evaluate the factors associated with survival. METHODS: The study included patients diagnosed with NPC who were followed and treated between 2008 and 2022. Hundred and forty-two patients from 6 centers were evaluated. The factors associated with disease-free survival (DFS) and overall survival (OS) were evaluated. RESULTS: The median age of our patients was 51 years (IQR: 16-81 years), and the male:female ratio was 2.5:1. A majority of patients (71%) had stage 3-4 disease. They had locally advanced disease, and 48 patients (34%) received ICT. Twenty patients (14%) received adjuvant therapy. The median follow-up was 41 months (range, 2.7-175.1 months). The median DFS in NPC was 92.6 months (range, 71.9-113.3 months), with a 40th month DFS of 70.9%. The median OS was 113 months (range, 91-135 months), with a 40th month OS of 84.7%. Median DFS was 95.3 months (range, 64.2-126.4 months) in patients who received ICT before CRT, which was longer than in the CRT-only group (p = 0.6). DFS at the 40th month was 75.1% in patients treated with ICT compared to 65.1% in the CRT-only group. Median OS was 117 months (range, 92-142 months) in patients receiving ICT, which was longer than in the CRT-only group (p = 0.4). OS at the 40th month was 86.7% in patients receiving ICT but 83.6% in the CRT-only group. CONCLUSIONS: Both the objective response rate and survival were longer in patients who radiologically responded to CRT following ICT. Nonresponse to ICT is a negative predictive indicator. The role of ICT in locally advanced NPC is increasing.

2.
J Chemother ; : 1-9, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38263804

RESUMO

The prognosis of patients with advanced HCC can vary widely depending on factors such as the stage of the cancer, the patient's overall health, and treatment regimens. This study aimed to investigate survival outcomes and associated factors in patients with hepatocellular carcinoma (HCC). In this retrospective study, data from 23 medical oncology clinics were analyzed. Progression-free survival (PFS) and overall survival (OS) values were estimated using the Kaplan-Meier method. Prognostic factors associated with survival which were identified in univariate analysis were subsequently evaluated in a multivariate Cox-regression survival analysis was conducted using the backward stepwise (Conditional LR) method to determine the independent predictors of PFS and OS. Of 280 patients, 131 received chemotherapy and 142 received sorafenib, 6 received atezolizumab plus bevacizumab and 1 received nivolumab for first-line setting. The median follow-up time was 30.4 (95%CI 27.1-33.6) months. For-first line, median PFS was 3.1 (95%CI2.7-3.5) months, and it was significantly longer in patients who received sorafenib or atezolizumab-bevacizumab or nivolumab (PFS 5.8 (95%CI 4.2-7.5) than in those received chemotherapy (PFS 2.1 (95%CI 1.9-2.3) in the first-line setting (p < 0.001). Multivariate analysis revealed that male gender (HR: 2.75, 95% CI: 1.53-4.94, p = 0.01), poor ECOG performance score (HR: 1.88, 95% CI: 1.10-3.21, p = 0.02), higher baseline AFP level (HR: 2.38, 95% CI: 1.54-3.67, p < 0.001) and upfront sorafenib treatment (HR,0.38; 95% CI: 0.23-0.62, p < 0.001) were significantly associated with shorter PFS. The median OS was 13.2 (95%CI 11.1-15.2) months. It was significantly longer in patients who received sorafenib or atezolizumab-bevacizumab or nivolumab in the first-line setting followed by TKIs (sorafenib or regorafenib, OS 18.6 (95%CI 13.8-23.5)) compared to those who received chemotherapy (OS 10.3 (95%CI 6.6-14.1)) in the first-line setting. The multivariate analysis revealed that upfront chemotherapy treatment approach, male gender (HR: 1.77, 95% CI: 1.07-2.94, p = 0.02), poor ECOG performance score (HR: 1.96, 95% CI: 1.24-3.09, p = 0.004) and Child-Pugh score, presence of extrahepatic disease (HR: 1.54, 95% CI: 1.09-2.18, p = 0.01), and higher baseline AFP value (HR: 1.50, 95% CI: 1.03-2.19, p = 0.03) were significantly associated with poor prognosis. Additionally, regarding of treatment sequence, upfront sorafenib followed by regorafenib showed a significantly lower risk of mortality (HR: 0.40, 95% CI: 0.25-0.66, p < 0.001). Sorafenib followed by regorafenib treatment was associated with a significantly lower risk of mortality rather than upfront sorafenib followed by BSC group or upfront chemotherapy followed by TKIs. These findings underscore the importance of the optimal treatment sequences to improve survival in patients with advanced HCC.

3.
Eur Radiol ; 2023 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-37947834

RESUMO

OBJECTIVES: The artificial intelligence competition in healthcare at TEKNOFEST-2022 provided a platform to address the complex multi-class classification challenge of abdominal emergencies using computer vision techniques. This manuscript aimed to comprehensively present the methodologies for data preparation, annotation procedures, and rigorous evaluation metrics. Moreover, it was conducted to introduce a meticulously curated abdominal emergencies data set to the researchers. METHODS: The data set underwent a comprehensive central screening procedure employing diverse algorithms extracted from the e-Nabiz (Pulse) and National Teleradiology System of the Republic of Türkiye, Ministry of Health. Full anonymization of the data set was conducted. Subsequently, the data set was annotated by a group of ten experienced radiologists. The evaluation process was executed by calculating F1 scores, which were derived from the intersection over union values between the predicted bounding boxes and the corresponding ground truth (GT) bounding boxes. The establishment of baseline performance metrics involved computing the average of the highest five F1 scores. RESULTS: Observations indicated a progressive decline in F1 scores as the threshold value increased. Furthermore, it could be deduced that class 6 (abdominal aortic aneurysm/dissection) was relatively straightforward to detect compared to other classes, with class 5 (acute diverticulitis) presenting the most formidable challenge. It is noteworthy, however, that if all achieved outcomes for all classes were considered with a threshold of 0.5, the data set's complexity and associated challenges became pronounced. CONCLUSION: This data set's significance lies in its pioneering provision of labels and GT-boxes for six classes, fostering opportunities for researchers. CLINICAL RELEVANCE STATEMENT: The prompt identification and timely intervention in cases of emergent medical conditions hold paramount significance. The handling of patients' care can be augmented, while the potential for errors is minimized, particularly amidst high caseload scenarios, through the application of AI. KEY POINTS: • The data set used in artificial intelligence competition in healthcare (TEKNOFEST-2022) provides a 6-class data set of abdominal CT images consisting of a great variety of abdominal emergencies. • This data set is compiled from the National Teleradiology System data repository of emergency radiology departments of 459 hospitals. • Radiological data on abdominal emergencies is scarce in literature and this annotated competition data set can be a valuable resource for further studies and new AI models.

4.
J Clin Med ; 12(19)2023 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-37835062

RESUMO

INTRODUCTION: This study aimed to assess the role of the adjusted PNI-IMDC risk scoring system in stratifying the intermediate group of metastatic RCC patients who received TKIS in the first-line setting. METHODS: A total of 185 patients were included. The adjusted PNI and IMDC model was used to divide the intermediate group into two groups: intermediate PNI-high and intermediate PNI-low groups. The statistical data were analyzed using Kaplan-Meier and Cox regression analysis. RESULTS: The results showed that the adjusted PNI-IMDC risk score, classic IMDC, and PNI had similar prognostic values. Adjusted PNI-IMDC risk score might be used for a more homogeneous differentiation of the classic intermediate group. On the other hand, multivariate analysis revealed that the presence of nephrectomy, adjusted favorable/intermediate (PNI-high) group, ECOG performance score, and presence of bone metastasis were independent predictors of OS. CONCLUSIONS: Pre-treatment PNI, as a valuable and potential add-on biomarker to the adjusted PNI-IMDC classification model, can be helpful for establishing an improved prognostic model for intermediate group mRCC patients treated with first-line TKISs. Further validation studies are needed to clarify these findings.

5.
Cureus ; 15(6): e40548, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37465788

RESUMO

OBJECTIVE: The systemic inflammatory response (SIR) is known as an important factor associated with tumorigenesis and tumor progression, and can be reflected by inflammatory markers. One of the markers that reflect this is the lung immune prognostic index (LIPI). It is based on a derived neutrophil-to-lymphocyte ratio (dNLR) and lactate dehydrogenase (LDH) level. We aimed to investigate the significance of LIPI in locally advanced rectal cancer (LARC) patients treated with neoadjuvant chemoradiotherapy (NACRT). METHODS: In this retrospective study, we stratified the patients according to LIPI score as good LIPI and intermediate (int)/poor LIPI. According to pathological response to NACRT, we divided the patients into two groups as those with complete response (CR) or near-CR, and those with partial response (PR) or poor/no response. We classified CR and near-CR as good response. We evaluated the predictive and prognostic significance of LIPI for NACRT response, disease-free survival (DFS), and overall survival (OS) by univariate and multivariate analyses. RESULTS: We included 137 patients in the results, with 72 (52.6%) having good LIPI and 65 (47.4%) having int/poor LIPI. The median follow-up period was 44.7 months (range: 10-105 months). Thirteen patients (18.0%) in the good LIPI group and 22 patients (34.0%) in the int/poor LIPI group achieved good response. In multivariate analysis, we found only the LIPI score as an independent risk factor (hazard ratio (HR): 2.4, p = 0.04) for NACRT response. Median DFS was 89.2 months (95% CI: 11.4-167.0) in the int/poor LIPI group; however, the DFS of all study populations and patients in the good LIPI group did not reach the median value. In multivariate analysis for DFS, we identified abdominoperineal resection (APR) (HR: 2.21, p = 0.02), presence of tumor deposit (HR: 2.96, p = 0.003), and int/poor LIPI score (HR: 2.07, p = 0.02) as separate risk variables. OS of all study populations and the patients in the LIPI groups did not reach the median value. In multivariate analysis for OS, we identified APR (HR: 2.74, p = 0.02), surgical margin positivity (HR: 12.94, p < 0.001), and adjuvant CT (HR: 0.20, p = 0.002) as separate risk variables for OS. CONCLUSION: This is the first study investigating the predictive and prognostic significance of LIPI in LARC patients treated with NACRT. The results revealed that int/poor LIPI was associated with a higher rate of good response but shorter DFS compared to good LIPI. The baseline LIPI score serves as an easily accessible and useful prognostic index, and it has significant potential for making appropriate treatment decisions in LARC.

6.
Future Oncol ; 19(10): 727-736, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37133230

RESUMO

Background: Ribociclib, palbociclib and abemaciclib are currently approved CDK4/6 inhibitors along with aromatase inhibitors as the first-line standard-of-care for patients with hormone receptor-positive, HER2-negative metastatic breast cancer. Methods: The authors report retrospective real-life data for 600 patients with estrogen receptor- and/or progesterone receptor-positive and HER2-negative metastatic breast cancer who were treated with ribociclib and palbociclib in combination with letrozole. Results & conclusion: The results demonstrated that the combination of palbociclib or ribociclib with letrozole has similar progression-free survival and overall survival benefit in real life for the patient group with similar clinical features. Specifically, endocrine sensitivity may be a factor to be considered in the treatment preference.


Assuntos
Neoplasias da Mama , Humanos , Feminino , Letrozol/uso terapêutico , Neoplasias da Mama/patologia , Estudos Retrospectivos , Aminopiridinas/uso terapêutico , Resultado do Tratamento , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Receptor ErbB-2
7.
Oncol Lett ; 25(5): 208, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37123028

RESUMO

Mucinous colorectal adenocarcinoma (MCAC) is a distinct subtype of colorectal carcinoma (CRC). The prognostic and predictive significance of mucinous histology remains controversial. It was aimed to investigate the prognostic and/or predictive role of mucinous histology in left-sided metastatic CRC (mCRC) with wild-type RAS. This is a retrospective multicenter study of mCRC treated with first line anti-EGFR combined 5-fluorouracil based chemotherapy (CT). Patients were stratified according to presence (>50% extracellular mucin) or absence of mucinous histology. Survival analyses were performed firstly regardless of treatment options and then performed as separating according to CT regimens. Additional analyses were performed for MCAC patients considering backbone CT regimens. A total of 125 patients were included, consisting of 40 (32.0%) patients with MCAC and 85 (68.0%) patients with non-MCAC. Median follow-up time was 19.7 months. Median progression-free survival (PFS) was 10.7 months in all patients, and PFS was lower in MCAC than non-MCAC (9.9 vs. 12.0 months, respectively, P=0.005). Median overall survival (OS) was 25.7 months in all patients. OS was lower in MCAC than non-MCAC (22.8 vs. 29.7 months, respectively, P=0.005). When considering backbone CT regimens, in multivariate analyses, mucinous histology was an independent prognostic factor for OS in both for mFOLFOX6 (HR: 1.92, P=0.04) and FOLFIRI (HR: 2.04, P=0.04) groups and was associated with poor PFS in only mFOLFOX6 (HR: 3.86, P<0.001) group. When outcomes were analyzed for the MCAC group, median OS of MCAC patients receiving mFOLFOX6 and FOLFIRI was 22.47 and 14.22 months, respectively (P=0.41). Median PFS of MCAC patients receiving mFOLFOX6 and FOLFIRI was 10.15 and 8.11 months, respectively (P=0.73). The study revealed poor prognosis of mucinous histology, both in whole study population and in backbone CT groups. Moreover, lower PFS of MCAC patients was revealed in only mFOLFOX6 group and this finding may be a valuable issue for the future research. However, considering all analyses, the present results did not indicate a special benefit of any backbone CT regimen for MCAC patients.

8.
Turk J Haematol ; 40(1): 50-63, 2023 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-36510383

RESUMO

Acute hemolytic transfusion reactions (AHTRs) are feared complications of packed red blood cell (PRBC) transfusions. This study aimed to investigate the clinical consequences of isolated enzyme-phase crossmatch-incompatible PRBC transfusions by clinically observing all events during the study period at a single institution with the primary goal of detecting AHTRs. Ninety-four transfusions of interest were administered during the study period. Laboratory investigations were adequate in 73 episodes, where no AHTR developed and a mean hemoglobin concentration rise of 1.1 g/dL was documented. Three transfusions were terminated prematurely; however, further investigations ruled out AHTR. The remaining 21 transfusions were also completed uneventfully without noteworthy clinical deterioration. This study's results provide clinical validation to omit pretransfusion screening with enzyme-phase crossmatch and document the safety and short-term efficacy of isolated enzyme-phase incompatible transfusions. The findings may encourage future clinical research to better understand the long-term efficacy of such transfusions, which may be valuable for transfusion-dependent patients.


Assuntos
Transfusão de Eritrócitos , Reação Transfusional , Humanos , Transfusão de Eritrócitos/efeitos adversos , Estudos Transversais , Transfusão de Sangue , Tipagem e Reações Cruzadas Sanguíneas , Incompatibilidade de Grupos Sanguíneos
9.
Acta Radiol ; 64(5): 2040-2049, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36447438

RESUMO

BACKGROUND: Prognostic markers in metastatic renal cell cancer (mRCC) are still insufficient. Any prognostic model objectively determines disease burden. PURPOSE: To investigate the relationship between 18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) parameters and outcomes in mRCC, and to define a revised International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) model for the intermediate-risk group. MATERIAL AND METHODS: A retrospective study of mRCC was conducted. To investigate the prognostic significance of 18F-FDG PET/CT parameters, maximum standardized uptake value (SUVmax), total lesion glycolysis (TLG), and metabolic tumor volume (MTV) were determined in pre-treatment images. Cutoff values were defined by ROC curve analyses and their association with outcomes was analyzed. Additionally, a TLG-adjusted IMDC model was created by stratifying intermediate-risk group patients according to TLG levels. RESULTS: The study included 52 patients. The disease control rate (DCR) was 61.5% and median overall survival (OS) was 18 months (95% confidence interval=9.2-25.8). In the univariate analyses, IMDC score, MTV, and TLG were prognostic factors for Disease Control Rate (DCR), and Eastern Cooperative Oncology Group (ECOG)-Performance Status (PS), IMDC score, lactate dehydrogenase (LDH), treatment option, MTV, and TLG were prognostic factors for OS (P < 0.05 each). In the multivariate analyses, MTV was an independent prognostic factor for DCR, and ECOG-PS, LDH, IMDC score, and TLG were independent prognostic factors for OS. According to the revised-IMDC model, the intermediate-favorable group showed longer OS than the intermediate-unfavorable group. CONCLUSION: Pretreatment MTV was independent prognostic factor for DCR and ECOG-PS, LDH, IMDC score, and TLG were independent prognostic factors for OS. Revised-IMDC model could identify patients with a worse prognosis among the IMDC intermediate-risk group.


Assuntos
Carcinoma de Células Renais , Neoplasias Renais , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Fluordesoxiglucose F18/metabolismo , Carcinoma de Células Renais/diagnóstico por imagem , Prognóstico , Estudos Retrospectivos , Neoplasias Renais/diagnóstico por imagem , Carga Tumoral , Compostos Radiofarmacêuticos
10.
Orthop Traumatol Surg Res ; 109(3): 103491, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36455864

RESUMO

BACKGROUND: Advanced age and presence of comorbidities affect prognosis and treatment decisions in patients with soft tissue sarcoma (STS). However, coeffect of age and comorbidities is still unknown. We aimed to investigate prognostic value of age-adjusted Charlson Comorbidity Index (ACCI) in trunk and extremity STS operated with curative intent. HYPOTHESIS: Preoperative ACCI might predict survival outcomes independently in patients with STS of trunk and extremities. PATIENTS AND METHODS: The study included 151 patients and ACCI was calculated for each patient. We categorized the patients into two groups according to median ACCI. We retrospectively collected data about clinicopathologic and treatment-related factors, and evaluated potential prognostic factors for disease-free survival (DFS) and overall survival (OS) using univariate and multivariate analyses. RESULTS: Median age was 50 (18-86) years. There were 89 male and 62 female patients. Lower extremities were the most common tumor sites (73.5%). Most of the patients had high grade tumors (84.1%) and stage 3 disease (66.9%). Radiotherapy and chemotherapy were carried out in 106 and 58 patients, respectively. Overall prevalence of comorbidity was 29.1%. Median ACCI was 3 (2-9). Older age (p<0.001), worse performance status (p<0.001), larger tumor size (p=0.03), higher grade tumors (p=0.03) and advanced stage (p=0.04) were associated with higher ACCI (≥3). Median follow-up time was 32 months, 50.3% of patients had disease recurrence, and 35.8% died. Median DFS (p=0.001) and OS (p=0.001) of patients with low ACCI (<3) were significantly longer than patients with high ACCI. Multivariate analysis determined ACCI as an independent prognostic indicator for both DFS (HR 1.72, p=0.02) and OS (HR 2.02, p=0.04). DISCUSSION: ACCI is a valuable prognostic tool to be used in the preoperative setting of patients with STS. Higher ACCI was found to be independently associated with worse survival outcomes. For each patient with STS, evaluating comorbidities and combining them with age appears to be a critical step in modifying therapy options. LEVEL OF EVIDENCE: IV, retrospective observational study.


Assuntos
Sarcoma , Neoplasias de Tecidos Moles , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Recidiva Local de Neoplasia , Extremidades , Comorbidade , Sarcoma/cirurgia , Extremidade Inferior
11.
Eurasian J Med ; 54(3): 248-258, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35943079

RESUMO

OBJECTIVE: The artificial intelligence competition in healthcare was organized for the first time at the annual aviation, space, and technology festival (TEKNOFEST), Istanbul/Türkiye, in September 2021. In this article, the data set preparation and competition processes were explained in detail; the anonymized and annotated data set is also provided via official website for further research. MATERIALS AND METHODS: Data set recorded over the period covering 2019 and 2020 were centrally screened from the e-Pulse and Teleradiology System of the Republic of Türkiye, Ministry of Health using various codes and filtering criteria. The data set was anonymized. The data set was prepared, pooled, curated, and annotated by 7 radiologists. The training data set was shared with the teams via a dedicated file transfer protocol server, which could be accessed using private usernames and passwords given to the teams under a nondisclosure agreement signed by the representative of each team. RESULTS: The competition consisted of 2 stages. In the first stage, teams were given 192 digital imaging and communications in medicine images that belong to 1 of 3 possible categories namely, hemorrhage, ischemic, or non-stroke. Teams were asked to classify each image as either stroke present or absent. In the second stage of the competition, qualifying 36 teams were given 97 digital imaging and communications in medicine images that contained hemorrhage, ischemia, or both lesions. Among the employed methods, Unet and DeepLabv3 were the most frequently observed ones. CONCLUSION: Artificial intelligence competitions in healthcare offer good opportunities to collect data reflecting various cases and problems. Especially, annotated data set by domain experts is more valuable.

12.
Nutr Cancer ; 74(7): 2499-2507, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35416100

RESUMO

This study aims to evaluate whether sarcopenia, measured by chest computed tomography (CT), affects survival outcomes and postoperative complications in soft tissue sarcoma (STS) patients undergoing surgery. In this retrospective study, CT scans of 79 patients were reviewed to measure pectoralis and T12 vertebra muscle area. Both were then adjusted for height (cm2/m2) as pectoralis muscle index (PMI) and T12 vertebra muscle index (TMI). Analyses were performed by dichotomizing muscle indices at gender-specific 50th percentile; PMI and TMI < 50th percentile were defined as low, and ≥50th percentile as high. Overall postsurgical complication rate (PCR) was 16%. Median length of hospital stay (LOHS) was 10 days (3-90). PMI and TMI were significantly lower in women (p = 0.02, p = 0.04). Median body mass index was significantly higher in high PMI and TMI groups (p = 0.01 for both). PCR and LOHS were similar between low and high PMI and TMI groups. Median follow-up was 29 months, 37 patients had recurrence and 23 died. No significant difference was noted between low and high PMI and TMI groups, in terms of disease-free or overall survival. PMI and TMI as measured by chest CT had no impact on survival outcomes or postoperative complications in localized STS.


Assuntos
Músculos do Dorso/diagnóstico por imagem , Músculos Peitorais/diagnóstico por imagem , Complicações Pós-Operatórias/etiologia , Sarcoma/cirurgia , Sarcopenia/diagnóstico por imagem , Neoplasias de Tecidos Moles/cirurgia , Feminino , Humanos , Músculo Esquelético/diagnóstico por imagem , Complicações Pós-Operatórias/diagnóstico por imagem , Complicações Pós-Operatórias/epidemiologia , Prognóstico , Estudos Retrospectivos , Sarcopenia/etiologia , Tomografia Computadorizada por Raios X/métodos
13.
J Colloid Interface Sci ; 402: 327-33, 2013 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-23628199

RESUMO

Poly(4-vinyl pyridine) (p(4-VP)) particles were synthesized by a simple micro-emulsion polymerization technique using sodium dodecyl sulfate (SDS) as surfactant. The prepared p(4-VP) particles were then treated various modifying agents with different functional groups. The modifying agents used in the modification of p(4-VP) particles are N-alkyl quaternizing agents such as 2-bromo ethanol (-OH), 4-bromo butyronitrile (-CN), and 2-bromoethylamine hydrobromide (-NH2). The functional groups on the modified p(4-VP) particles were confirmed by FT-IR spectrometry and zeta potential measurements. The size of p(4-VP) and modified p(4-VP) particles is between 300 and 700 nm, and the zeta potentials of modified p(4-VP) particles were varied between 2 and 45 mV. Moreover, a second post-modification was carried out on 4-bromo butyronitrile modified p(4-VP) particles by amidoximation. The modified p(4-VP) particles were also tested for their antimicrobial effects against various bacteria such as Staphylococcus aureus, Bacillus subtilis, and Escherichia coli. It was found that p(4-VP) do not posses antimicrobial properties, whereas the modified forms especially p(4-VP)(+) and p(4-VP)(+)-NH3(+) showed highly bactericidal characteristics. Due to the positive charge by means of new functional groups generated on p(4-VP)-based particles by modification, the absorption of oppositely charged reagents such as fluorescein sodium salt (FSS) was increased drastically. For example, the absorption capacity of unmodified p(4-VP) was increased to 93.3, 93.5, and 93.6 form 37.6 mg for p(4-VP)(+), p(4-VP)(+)-NH2, p(4-VP)(+)-NH3(+), respectively. Moreover, upon modification, except Cu(II), Co(II) and Ni(II) absorption capacities were increased from about 15.9, and 22.1 mg to 21.1 and 39,1 mg per gram particles.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/síntese química , Polivinil/química , Polivinil/síntese química , Adsorção , Anti-Infecciosos/farmacologia , Bactérias/crescimento & desenvolvimento , Metais Pesados/química , Polivinil/farmacologia , Dodecilsulfato de Sódio/química , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície
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