Membrane technology for pesticide removal from aquatic environment: Status quo and way forward.

The noxious side effects of pesticides on human health and environment have prompted the search of effective and reliable treatment techniques for pesticide removal. The removal of pesticides can be accomplished through physical, chemical and biologicals. Physical approaches such as filtration and adsorption are prevailing pesticide removal strategies on account of their effectiveness and ease of operation. Membrane-based filtration technology has been recognized as a promising water and wastewater treatment approach that can be used for a wide range of organic micropollutants including pesticides. Nanofiltration (NF), reverse osmosis (RO) and forward osmosis (FO) have been increasingly explored for pesticide removal from aquatic environment owing to their versatility and high treatment efficiencies. This review looks into the remedial strategies of pesticides from aqueous environment using membrane-based processes. The potentials and applications of three prevailing membrane processes, namely NF, RO and FO for the treatment of pesticide-containing wastewater are discussed in terms of the development of advanced membranes, separation mechanisms and system design. The challenges in regards to the practical implementation of membrane-based processes for pesticide remediation are identified. The corresponding research directions and way forward are highlighted. An in depth understanding of the pesticide nature, water chemistry and the pesticide-membrane interactions is the key to achieving high pesticide removal efficiency. The integration of membrane technology and conventional removal technologies represents a new dimension and the future direction for the treatment of wastewater containing recalcitrant pesticides.

Validity of screening tools for dementia and mild cognitive impairment among the elderly in primary health care: a systematic review.

OBJECTIVES: This systematic review aims to provide updated and comprehensive evidence on the validity and feasibility of screening tools for mild cognitive impairment (MCI) and dementia among the elderly at primary healthcare level. STUDY DESIGN: A review of articles was performed. METHODS: A search strategy was used by using electronic bibliographic databases including PubMed, Embase and CENTRAL for published studies and reference list of published studies. The articles were exported to a bibliographic database for further screening process. Two reviewers worked independently to screen results and extract data from the included studies. Any discrepancies were resolved and confirmed by the consensus of all authors. RESULTS: There were three screening approaches for detecting MCI and dementia - screening by a healthcare provider, screening by a self-administered questionnaire and caretaker informant screening. Montreal Cognitive Assessment (MoCA) was the most common and preferable tool for MCI screening (sensitivity [Sn]: 81-97%; specificity [Sp]: 60-86%), whereas Addenbrooke's Cognitive Examination (ACE) was the preferable tool for dementia screening (Sn: 79-100%; Sp: 86%). CONCLUSION: This systematic review found that there are three screening approaches for detecting early dementia and MCI at primary health care. ACE and MoCA are recommended tools for screening of dementia and MCI, respectively.

Dental students' perceptions on the contribution and impact role of a clinical teacher.

OBJECTIVES: This study was conducted in University of Malaya to evaluate student perceptions on the contribution and role of an effective clinical teacher based on the cognitive apprenticeship model in clinical practice. METHODS: Self-administered questionnaires were distributed to 233 undergraduate dental students involved with clinical teaching. This modified and validated questionnaire focusing on students' learning environment was used in order to gain relevant information related to dental clinical teaching. Six domains with different criteria applicable to clinical teaching in dentistry were selected consisting of modelling (four criteria), coaching (four criteria), scaffolding (four criteria), articulation (four criteria), reflection (two criteria) and general learning environment (six criteria). Data analyses were performed using IBM SPSS Statistics 20. RESULTS: Majority of the students expressed positive perceptions on their clinical learning experience towards the clinical teachers in the Faculty of Dentistry, University of Malaya, in all criteria of the domains. Few negative feedbacks concerning the general learning environment were reported. CONCLUSION: Further improvement in the delivery of clinical teaching preferably by using wide variety of teaching-learning activities can be taken into account through students' feedback on their learning experience.

Pairing as an instructional strategy to promote soft skills amongst clinical dental students.

Training dentists today is challenging as they are expected to provide a wide range of dental care. In the provision of good dental care, soft skills are equally important as clinical skills. Therefore in dental education the development of soft skills are of prime concern. This study sought to identify the development of soft skills when dental students are paired in their clinical training. In this perception study, four open-ended items were used to elicit students' feedback on the appropriateness of using clinical pairing as an instructional strategy to promote soft skills. The most frequently cited soft skills were teamwork (70%) and communication (25%) skills. However, both negative and positive behaviours were reported. As for critical thinking and problem solving skills, more positive behaviours were reported for abilities such as to explain, analyze, find ideas and alternative solutions, and make decisions. Leadership among peers was not evident as leading without legitimate authority could be a hindrance to its development. If clinical pairing is to be used as an effective instructional strategy to promote soft skills amongst students, clear guidelines need to be developed to prepare students to work in a dental team and the use of appropriate assessment tools can facilitate the development of these soft skills.

pH dependent poly[2-(methacryloyloxyethyl)trimetylammonium chloride-co-methacrylic acid]hydrogels for enhanced targeted delivery of 5-fluorouracil in colon cancer cells.

Stimuli responsive hydrogels have shown enormous potential as a carrier for targeted drug delivery. In this study we have developed novel pH responsive hydrogels for the delivery of 5-fluorouracil (5-FU) in order to alleviate its antitumor activity while reducing its toxicity. We used 2-(methacryloyloxyethyl) trimetylammonium chloride a positively charged monomer and methacrylic acid for fabricating the pH responsive hydrogels. The released 5-FU from all except hydrogel (GEL-5) remained biologically active against human colon cancer cell lines [HT29 (IC50 = 110-190 µg ml(-1)) and HCT116 (IC50 = 210-390 µg ml(-1))] but not human skin fibroblast cells [BJ (CRL2522); IC50 ≥ 1000 µg ml(-1)]. This implies that the copolymer hydrogels (1-4) were able to release 5-FU effectively to colon cancer cells but not normal human skin fibroblast cells. This is probably due to the shorter doubling time that results in reduced pH in colon cancer cells when compared to fibroblast cells. These pH sensitive hydrogels showed well defined cell apoptosis in HCT116 cells through series of events such as chromatin condensation, membrane blebbing, and formation of apoptotic bodies. No cell killing was observed in the case of blank hydrogels. The results showed the potential of these stimuli responsive polymer hydrogels as a carrier for colon cancer delivery.

Multicenter comparative trial of the V-scope system for therapeutic ERCP.

BACKGROUND AND STUDY AIMS: A new duodenoscope (the V-scope), with a modified elevator used in combination with a dedicated short guide wire, constitutes the V-system. This system is intended to allow fixation of the guide wire at the elevator lever, thereby enhancing the speed and reliability of accessory exchange over a guide wire during ERCP. The aim of this study was to evaluate the extent to which the V-system provides improved efficiency in comparison with conventional duodenoscope and guide wire combinations. PATIENTS AND METHODS: This was an industry-sponsored multicenter randomized trial. Patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) procedures in which treatment was anticipated were randomly assigned to the V-system or to a conventional duodenoscope and accessories used routinely in each center. The parameters recorded included the total case time, fluoroscopy time, catheter/guide wire exchange time, guide wire repositioning, loss of guide wire access, and success or failure of guide wire fixation when using the V-system. RESULTS: Fifty patients were included, 22 in the conventional group and 28 in the V-system group. A total of 135 exchanges were carried out. The patients had up to six exchanges. The median exchange time was 19.4 s with the V-system and 31.7 s with the conventional systems ( P < 0.001). Guide wire repositioning was required less often in the V-system group ( P = 0.0005). The V-system effectively locked the guide wire in 63 of 71 exchanges (89 %). Loss of guide wire access occurred in two patients in the conventional group and four in the V-system group, attributable to failure to lock the guide wire early during the experience (no significant differences). CONCLUSIONS: The V-system can effectively secure the guide wire during accessory exchange in ERCP and reduces the time required to exchange accessories. This may enhance overall efficiency during ERCP.

Long term survival after pancreatic resection for pancreatic adenocarcinoma.

OBJECTIVE: The aim of this study was to determine the long term survival of patients with pancreatic adenocarcinoma who underwent surgical resection and to assess the association of clinical, pathological, and treatment features with survival. METHODS: Between January, 1990, and December, 1998, 125 patients underwent a pancreaticoduodenal or partial pancreatic resection for pancreatic ductal adenocarcinoma at our institution. The records of these patients were reviewed for demographics, tumor characteristics including size, histological grade, margin status, lymph node status, surgical TNM staging, and postoperative adjuvant therapy. The primary outcome variable analyzed was survival. RESULTS: A total of 116 patients had complete follow-up and were included in the final analysis. The median survival after surgery was 16 months. The 1-, 3-, 5-, and 7-yr survival rates for all 116 patients were 60%, 23%, 19%, and 11%, respectively. The 1-, 3-, 5-, and 7-yr survival rates for patients who received adjuvant therapy were 69%, 28%, 23%, and 18% compared with 20% and 0% in patients who did not receive adjuvant therapy (p < 0.0001). The 1-, 3-, 5-, and 7-yr survival rates for patients with negative lymph nodes were 73%, 38%, 26%, and 22% compared with survival rates of 52%, 14%, 14%, and 9% in patients with positive lymph nodes (p = 0.01). In multivariate analyses, adjuvant therapy was the only feature found to be strongly associated with survival (hazards ratio = 0.26, 95% CI = 0.15-0.44). CONCLUSIONS: The overall 5- and 7-yr survival rates of 19% and 11% in our study further validate that surgical resection in patients with pancreatic adenocarcinoma can result in long term survival, particularly when performed in association with adjuvant chemoradiation.

Endosonography is superior to angiography in the preoperative assessment of vascular involvement among patients with pancreatic carcinoma.

Surgical exploration in patients with pancreatic carcinoma without adequate preoperative attempts to determine resectability results in resection in only a minority of patients. Besides distant metastases, involvement of the major vessels is the most important parameter for determining resectability in patients with pancreatic adenocarcinoma. Angiography has been an integral part of pancreatic cancer staging. Lately, endoscopic ultrasound (EUS) has emerged as a more accurate tool in the diagnosis and staging of pancreatic cancer. We hypothesize that EUS is more accurate than selective venous angiography (SVA) for assessing resectability of pancreatic adenocarcinoma based on preoperative evaluation of vascular involvement. Twenty-one patients who met the inclusion criteria were prospectively evaluated with both EUS and SVA before undergoing surgical exploration for attempted curative resection. Vascular involvement was determined by EUS and SVA using previously described criteria. The sensitivity, specificity, and overall accuracy of EUS and SVA in assessing vascular involvement were compared, using surgical exploration as the gold standard. Endoscopic ultrasound had a higher sensitivity than SVA for detecting vascular involvement (86% vs. 21%, respectively; p = 0.0018). The specificity and accuracy of EUS for detecting vascular involvement was 71% and 81%, respectively. In contrast, the specificity and accuracy of SVA for detecting vascular involvement was 71% and 38%, respectively. Endoscopic ultrasound is significantly more sensitive than angiography for detecting vascu lar involvement in patients with pancreatic adenocarcinoma and, thus, may improve patient selection for attempted curative resection.

Can EUS alone differentiate between malignant and benign cystic lesions of the pancreas?

OBJECTIVE: The aim of this study was to evaluate the ability of endoscopic ultrasound (EUS) alone to predict and differentiate malignant from benign cystic lesions of the pancreas. METHODS: From January, 1995, to August, 1999, 98 cases of pancreatic cystic lesions were evaluated by EUS; all of these were originally imaged by cross-sectional modalities that were not diagnostic. Among these, surgical/pathological correlation was available in 48 patients. The original endosonographic images were reviewed by two endosonographers who were blinded to each other's interpretation and to the surgical and pathological interpretation. The EUS images were assessed for the presence or absence of the following characteristics: 1) wall, 2) solid component, 3) septae, 4) lymphadenopathy, and 5) number of cysts. These characteristics were then correlated with the surgical and pathological findings and were assessed to determine if any were predictors of the lesion being benign or malignant. RESULTS: For reviewer A, the presence of a solid component by EUS was the only statistically significant predictor of malignancy (odds ratio = 4.73, 95% CI = 1.13-19.68, p = 0.03). However, 61% of patients with benign lesions were also interpreted by EUS to have a solid component. For reviewer B, none of the features were found to be significant predictors of a malignant lesion. When the results of both reviewers were combined, the presence of a solid component was not found to be a statistically significant predictor of malignancy (odds ratio = 1.046, 95% CI = 0.99-1.09, p = 0.07). CONCLUSION: Endosonographic features cannot reliably differentiate between benign and malignant cystic lesions of the pancreas after a nondiagnostic cross-sectional modality.

EUS in preoperative staging of pancreatic cancer.

BACKGROUND: Endoscopic ultrasound (EUS) is believed to be highly accurate in the local (T) and nodal (N) staging of pancreatic cancer. However, there are scant data concerning the predictive value of EUS for resectability of pancreatic adenocarcinoma. This study was performed to determine the accuracy of TNM staging by EUS in patients with pancreatic adenocarcinoma and to evaluate the role of preoperative TNM staging by EUS for determining resectability in patients with pancreatic adenocarcinoma. METHODS: This is a retrospective review of a cohort of 89 patients evaluated preoperatively with EUS for pancreatic adenocarcinoma between January 1995 and December 1997. Preoperative TNM classification by EUS was compared with surgical and histopathologic TNM staging. Resectability rates were determined and compared with the preoperative TNM staging by EUS. RESULTS: The overall accuracy of EUS for T and N staging was found to be 69% and 54%, respectively. The overall proportion of tumors that were deemed resectable by EUS and were actually found to be resectable during surgical exploration was 46%. The proportion of tumors staged as T4 N1, T4 N0, T3 N1 and T3 N0 by EUS that were found to be resectable during surgical exploration was 45%, 37%, 44% and 62%, respectively. CONCLUSIONS: In a tertiary referral patient population, EUS is not as accurate as previously reported in the T and N staging of pancreatic cancer. EUS is also not predictive of resectability in stage T3 or T4 pancreatic cancer.

Role of endoscopic ultrasound and magnetic resonance imaging in the preoperative staging of pancreatic adenocarcinoma.

OBJECTIVE: Endoscopic ultrasound (EUS) and magnetic resonance imaging (MRI) have both been assessed individually as staging modalities for pancreatic cancer. The aim of our study was to assess whether tumor staging by both EUS and MRI in the same cohort of patients could predict resectability and unresectability in patients with pancreatic cancer. METHODS: A review of 63 patients evaluated preoperatively with both EUS and MRI for pancreatic adenocarcinoma between January 1995 and December 1998 was done. Patients were staged as resectable or unresectable by predefined criteria. Preoperative staging by both modalities was compared to surgical outcome and the sensitivity and predictive values of each modality for determining resectability and unresectability was determined. RESULTS: EUS did not allow for complete T- and N-staging in 10 patients; therefore, for EUS, the final analysis was done on 63 of 73 patients (86%). EUS correctly staged 22 of 36 patients with resectable tumors. The sensitivity of EUS for resectability was 61%, with a positive predictive value of 69%. All 73 patients had complete MRI examinations; therefore, the final analysis was done on all 73 patients. MRI correctly staged 30 of 41 patients with resectable tumors. The sensitivity of MRI for predicting resectability was 73% with a positive predictive value of 77%. MRI and EUS both predicted resectability in 18 patients, of whom 16 (89%) were found to be resectable on surgical exploration. MRI and EUS both predicted unresectability in 17 (27%) patients, of whom 4 (24%) were found to be resectable on surgical exploration. When both MRI and EUS agreed on resectability, the positive predictive value for resectability was 89%. When both MRI and EUS agreed on unresectability, the positive predictive value for unresectability was 76%. CONCLUSIONS: Neither MRI nor EUS alone were highly sensitive or predictive of resectability. However, when both tests agreed on resectability, nearly all patients were found to be resectable on surgical exploration.

Dyspepsia and heartburn.

Dyspepsia and heartburn are the two cardinal symptoms of foregut dysfunction. When confronting such a problem, that physician must first learn to discern between the two, because treatment can be quite different for the conditions presenting with these symptoms. This article details the approach to work-up and treatment of patients presenting with dyspepsia or heartburn.

Sporadic Zollinger-Ellison syndrome with ectopic production of corticotropin: surgical management.

OBJECTIVE: To describe two patients with concurrent Zollinger-Ellison syndrome and ectopic production of corticotropin in whom Cushing's syndrome was managed surgically. METHODS: Two case vignettes are presented, and a general approach is discussed for determining a management strategy for optimal potential for survival. RESULTS: The prognosis associated with medical management of patients with sporadic Zollinger-Ellison syndrome and Cushing's syndrome attributable to ectopic production of adrenocorticotropic hormone (corticotropin) is dismal. Two surgical options may yield improved outcomes. The first approach is bilateral adrenalectomy followed by replacement therapy with corticosteroids and mineralocorticoids. The second surgical approach consists of removal of the organ producing the corticotropin (the liver) and performance of hepatic transplantation. These two treatment strategies were used in our two patients, both of whom had widely metastatic disease at the time of initial assessment. The patient who underwent bilateral adrenalectomy continued to do well 4 years postoperatively. CONCLUSION: Treatment of patients with Zollinger-Ellison syndrome and ectopic production of corticotropin presents a challenge. Because results with medical therapy have been suboptimal, aggressive surgical intervention seems warranted.