Strategies and Challenges of a Safe Fireplace Program in Rural Kenya: A Qualitative Study

There is a lack of information on effective burn prevention strategies. The objective of this study was to examine a safe fireplace program, as a method of burn prevention, in a resource-limited setting. We conducted a qualitative, phenomenological study at a community health and development program for a rural population in Kenya. Semi-structured, in-depth interviews were conducted with a purposive sample of community health workers involved with the safe fireplace program. Data were reviewed iteratively and coded independently by two researchers using NVivo 12. The study included five participants. Reflections from participants fell into three main domains: (1) effective methods of education, (2) strategies to incorporate stakeholders, and (3) implementation challenges. The results of this study emphasize the importance of community engagement in implementing a successful burn injury prevention program in a resource-limited setting. The participants involved in this study reported that rather than focusing on resources outside the community, effective methods of education and strategies for incorporating stakeholders depended on involving peers and community leaders. The challenges to the program were similarly specific to community concerns about resources and maintenance. These findings provide information to guide future community health programs in creating successful models for burn prevention strategies in resource-limited areas.

Operative Case Volumes and Variation for General Surgery Training in East, Central, and Southern Africa

BACKGROUND

Operative experience is a necessary part of surgical training. The College of Surgeons of East, Central, and Southern Africa (COSECSA), which oversees general surgery training programs in the region, has implemented guidelines for the minimum necessary case volumes upon completion of two (Membership) and five (Fellowship) years of surgical training. We aimed to review trainee experience to determine whether guidelines are being met and examine the variation of cases between countries.

METHODS

Operative procedures were categorized from a cohort of COSECSA general surgery trainees and compared to the guideline minimum case volumes for Membership and Fellowship levels. The primary and secondary outcomes were total observed case volumes and cases within defined categories. Variations by country and development indices were explored.

RESULTS

One hundred ninety-four trainees performed 69,283 unique procedures related to general surgery training. The review included 70 accredited hospitals and sixteen countries within Africa. Eighty percent of MCS trainees met the guideline minimum of 200 overall cases; however, numerous trainees did not meet the guideline minimum for each procedure. All FCS trainees met the volume target for total cases and orthopedics; however, many did not meet the guideline minimums for other categories, especially breast, head and neck, urology, and vascular surgery. The operative experience of trainees varied significantly by location and national income level.

CONCLUSIONS

Surgical trainees in East, Central, and Southern Africa have diverse operative training experience. Most trainees fulfill the overall case volume requirements; however, further exploration of how to meet the demands of specific categories and procedures is necessary.

Textbook outcome following oesophagectomy for cancer: international cohort study

Background

Textbook outcome has been proposed as a tool for the assessment of oncological surgical care. However, an international assessment in patients undergoing oesophagectomy for oesophageal cancer has not been reported. This study aimed to assess textbook outcome in an international setting.

Methods

Patients undergoing curative resection for oesophageal cancer were identified from the international Oesophagogastric Anastomosis Audit (OGAA) from April 2018 to December 2018. Textbook outcome was defined as the percentage of patients who underwent a complete tumour resection with at least 15 lymph nodes in the resected specimen and an uneventful postoperative course, without hospital readmission. A multivariable binary logistic regression model was used to identify factors independently associated with textbook outcome, and results are presented as odds ratio (OR) and 95 per cent confidence intervals (95 per cent c.i.).

Results

Of 2159 patients with oesophageal cancer, 39.7 per cent achieved a textbook outcome. The outcome parameter ‘no major postoperative complication’ had the greatest negative impact on a textbook outcome for patients with oesophageal cancer, compared to other textbook outcome parameters. Multivariable analysis identified male gender and increasing Charlson comorbidity index with a significantly lower likelihood of textbook outcome. Presence of 24-hour on-call rota for oesophageal surgeons (OR 2.05, 95 per cent c.i. 1.30 to 3.22; P = 0.002) and radiology (OR 1.54, 95 per cent c.i. 1.05 to 2.24; P = 0.027), total minimally invasive oesophagectomies (OR 1.63, 95 per cent c.i. 1.27 to 2.08; P < 0.001), and chest anastomosis above azygous (OR 2.17, 95 per cent c.i. 1.58 to 2.98; P < 0.001) were independently associated with a significantly increased likelihood of textbook outcome.

Conclusion

Textbook outcome is achieved in less than 40 per cent of patients having oesophagectomy for cancer. Improvements in centralization, hospital resources, access to minimal access surgery, and adoption of newer techniques for improving lymph node yield could improve textbook outcome.

Textbook outcome following oesophagectomy for cancer: international cohort study

BACKGROUND

Textbook outcome has been proposed as a tool for the assessment of oncological surgical care. However, an international assessment in patients undergoing oesophagectomy for oesophageal cancer has not been reported. This study aimed to assess textbook outcome in an international setting.

METHODS

Patients undergoing curative resection for oesophageal cancer were identified from the international Oesophagogastric Anastomosis Audit (OGAA) from April 2018 to December 2018. Textbook outcome was defined as the percentage of patients who underwent a complete tumour resection with at least 15 lymph nodes in the resected specimen and an uneventful postoperative course, without hospital readmission. A multivariable binary logistic regression model was used to identify factors independently associated with textbook outcome, and results are presented as odds ratio (OR) and 95 per cent confidence intervals (95 per cent c.i.).

RESULTS

Of 2159 patients with oesophageal cancer, 39.7 per cent achieved a textbook outcome. The outcome parameter 'no major postoperative complication' had the greatest negative impact on a textbook outcome for patients with oesophageal cancer, compared to other textbook outcome parameters. Multivariable analysis identified male gender and increasing Charlson comorbidity index with a significantly lower likelihood of textbook outcome. Presence of 24-hour on-call rota for oesophageal surgeons (OR 2.05, 95 per cent c.i. 1.30 to 3.22; P = 0.002) and radiology (OR 1.54, 95 per cent c.i. 1.05 to 2.24; P = 0.027), total minimally invasive oesophagectomies (OR 1.63, 95 per cent c.i. 1.27 to 2.08; P < 0.001), and chest anastomosis above azygous (OR 2.17, 95 per cent c.i. 1.58 to 2.98; P < 0.001) were independently associated with a significantly increased likelihood of textbook outcome.

CONCLUSION

Textbook outcome is achieved in less than 40 per cent of patients having oesophagectomy for cancer. Improvements in centralization, hospital resources, access to minimal access surgery, and adoption of newer techniques for improving lymph node yield could improve textbook outcome.

An Online, Modular Curriculum Enhances Surgical Education and Improves Learning Outcomes in East, Central, and Southern Africa: A Mixed-Methods Study

Objective

We aimed to determine the impact of a standardized curriculum on learning outcomes for surgical trainees in East, Central, and Southern Africa (ECSA).

Background

As surgical education expands throughout ECSA, there is a recognized need for a standardized curriculum. We previously described the design of a novel, large-scale, flipped-classroom, surgical curriculum for trainees in ECSA.

Methods

In January 2020, the first year of curricular content for trainees of the College of Surgeons of ECSA was released, containing 11 monthly thematic topics, each with 2 to 5 weekly modular subtopics. We aimed to evaluate 3 outcomes utilizing data sources incorporated into the curriculum structure. Learner engagement was assessed by the number of trainees completing curriculum topics. User experience was evaluated using quantitative and qualitative feedback responses to embedded surveys for each content week. Curriculum impact on trainee examination performance was assessed by comparing certification examination scores stratified by the number of curricular topics each trainee completed.

Results

Two hundred seventy-one trainees (96%) in 17 countries accessed at least 1 weekly module. Trainees completed a median of 9 topics (interquartile range: 6-10). The feedback survey response rate was 92% (5742/6233). Quantitative and qualitative responses were positive in overall module value (93.7% + 2.6%), amount of learning experienced (97.9% + 1.4%), confidence in achieving learning objectives (97.1% + 2.4%), and ease of use of the module (77.6% + 5.98%). Topic-related certification examination performance improved significantly with increased completion of thematic topics.

Conclusions

A standardized surgical curriculum in ECSA demonstrated excellent trainee usage, positive feedback, and improved examination scores.

Design of a Novel Online, Modular, Flipped-classroom Surgical Curriculum for East, Central, and Southern Africa

Objective

We describe a structured approach to developing a standardized curriculum for surgical trainees in East, Central, and Southern Africa (ECSA).

Summary Background Data

Surgical education is essential to closing the surgical access gap in ECSA. Given its importance for surgical education, the development of a standardized curriculum was deemed necessary.

Methods

We utilized Kern's 6-step approach to curriculum development to design an online, modular, flipped-classroom surgical curriculum. Steps included global and targeted needs assessments, determination of goals and objectives, the establishment of educational strategies, implementation, and evaluation.

Results

Global needs assessment identified the development of a standardized curriculum as an essential next step in the growth of surgical education programs in ECSA. Targeted needs assessment of stakeholders found medical knowledge challenges, regulatory requirements, language variance, content gaps, expense and availability of resources, faculty numbers, and content delivery method to be factors to inform curriculum design. Goals emerged to increase uniformity and consistency in training, create contextually relevant material, incorporate best educational practices, reduce faculty burden, and ease content delivery and updates. Educational strategies centered on developing an online, flipped-classroom, modular curriculum emphasizing textual simplicity, multimedia components, and incorporation of active learning strategies. The implementation process involved establishing thematic topics and subtopics, the content of which was authored by regional surgeon educators and edited by content experts. Evaluation was performed by recording participation, soliciting user feedback, and evaluating scores on a certification examination.

Conclusions

We present the systematic design of a large-scale, context-relevant, data-driven surgical curriculum for the ECSA region.

Treatment outcomes of esophageal cancer in Eastern Africa: protocol of a multi-center, prospective, observational, open cohort study

Background

Esophageal squamous cell carcinoma (ESCC) is a major cause of cancer morbidity and mortality in Eastern Africa. The majority of patients with ESCC in Eastern Africa present with advanced disease at the time of diagnosis. Several palliative interventions for ESCC are currently in use within the region, including chemotherapy, radiation therapy with and without chemotherapy, and esophageal stenting with self-expandable metallic stents; however, the comparative effectiveness of these interventions in a low resource setting has yet to be examined.

Methods

This prospective, observational, multi-center, open cohort study aims to describe the therapeutic landscape of ESCC in Eastern Africa and investigate the outcomes of different treatment strategies within the region. The 4.5-year study will recruit at a total of six sites in Kenya, Malawi and Tanzania (Ocean Road Cancer Institute and Muhimbili National Hospital in Dar es Salaam, Tanzania; Kilimanjaro Christian Medical Center in Moshi, Tanzania; Tenwek Hospital in Bomet, Kenya; Moi Teaching and Referral Hospital in Eldoret, Kenya; and Kamuzu Central Hospital in Lilongwe, Malawi). Treatment outcomes that will be evaluated include overall survival, quality of life (QOL) and safety. All patients (≥18 years old) who present to participating sites with a histopathologically-confirmed or presumptive clinical diagnosis of ESCC based on endoscopy or barium swallow will be recruited to participate. Key clinical and treatment-related data including standardized QOL metrics will be collected at study enrollment, 1 month following treatment, 3 months following treatment, and thereafter at 3-month intervals until death. Vital status and QOL data will be collected through mobile phone outreach.

Discussion

This study will be the first study to prospectively compare ESCC treatment strategies in Eastern Africa, and the first to investigate QOL benefits associated with different treatments in sub-Saharan Africa. Findings from this study will help define optimal management strategies for ESCC in Eastern Africa and other resource-limited settings and will serve as a benchmark for future research.

Trial registration

This study was retrospectively registered with the ClinicalTrials.gov database on December 15, 2021, NCT05177393.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-09124-5.

Postoperative outcomes in oesophagectomy with trainee involvement

BACKGROUND

The complexity of oesophageal surgery and the significant risk of morbidity necessitates that oesophagectomy is predominantly performed by a consultant surgeon, or a senior trainee under their supervision. The aim of this study was to determine the impact of trainee involvement in oesophagectomy on postoperative outcomes in an international multicentre setting.

METHODS

Data from the multicentre Oesophago-Gastric Anastomosis Study Group (OGAA) cohort study were analysed, which comprised prospectively collected data from patients undergoing oesophagectomy for oesophageal cancer between April 2018 and December 2018. Procedures were grouped by the level of trainee involvement, and univariable and multivariable analyses were performed to compare patient outcomes across groups.

RESULTS

Of 2232 oesophagectomies from 137 centres in 41 countries, trainees were involved in 29.1 per cent of them (n = 650), performing only the abdominal phase in 230, only the chest and/or neck phases in 130, and all phases in 315 procedures. For procedures with a chest anastomosis, those with trainee involvement had similar 90-day mortality, complication and reoperation rates to consultant-performed oesophagectomies (P = 0.451, P = 0.318, and P = 0.382, respectively), while anastomotic leak rates were significantly lower in the trainee groups (P = 0.030). Procedures with a neck anastomosis had equivalent complication, anastomotic leak, and reoperation rates (P = 0.150, P = 0.430, and P = 0.632, respectively) in trainee-involved versus consultant-performed oesophagectomies, with significantly lower 90-day mortality in the trainee groups (P = 0.005).

CONCLUSION

Trainee involvement was not found to be associated with significantly inferior postoperative outcomes for selected patients undergoing oesophagectomy. The results support continued supervised trainee involvement in oesophageal cancer surgery.

Surgical Simulation in East, Central, and Southern Africa: A Multinational Survey

BACKGROUND

High-income countries have increased the use of simulation-based training and assessment for surgical education. Learners in low- and middle-income countries may have different educational needs and levels of autonomy but they and their patients could equally benefit from the procedural training simulation provides. We sought to characterize the current state of surgical skills simulation in East, Central, and Southern Africa and determine residents' perception and future interest in such activities.

METHODS

A survey was created via collaboration and revision between trainees and educators with experiences spanning high-income countries and low- and middle-income countries. The survey was administered on paper to 76 trainees (PGY2-3) who were completing the College of Surgeons of East, Central, and Southern Africa (COSECSA) Membership of the College of Surgeons examination in Kampala, Uganda in December 2019. Data from paper responses were summarized using descriptive statistics and frequencies.

RESULTS

We received responses from 43 trainees (57%) from 11 countries in sub-Saharan Africa who participated in the examination. Fifty-eight percent of respondents reported having dedicated space for surgical skills simulation training, and most (91%) had participated in some form of simulation activity at some point in their training. However, just 16% used simulation as a regular part of training. The majority of trainees (90%) felt that surgical skills learned in simulation were transferrable to the operating room and agreed it should be a required part of training. Seventy-one percent of trainees felt that simulation could objectively measure technical skills, and 73% percent of respondents agreed that simulation should be integrated into formal assessment. However, residents split on whether proficiency in simulation should be achieved prior to operative experience (54%) and if nontechnical skills could be measured (51%). The most common cited barriers to the integration of surgical simulation into residents' education were lack of suitable tools and models (85%), funding (73%), and maintenance of facilities (49%).

CONCLUSIONS

Residents from East, Central, and Southern Africa strongly agree that simulation is a valuable educational tool and ought to be required during their surgical residency. Barriers to achieving this goal include availability of affordable tools, adequate funding and confidence in the value of the educational experience. Trainees affirm further efforts are necessary to make simulation more widely available in these contexts.

Indoor wood combustion, carcinogenic exposure and esophageal cancer in southwest Kenya

BACKGROUND

Exposure to polycyclic aromatic hydrocarbons (PAHs) is a risk factor for esophageal squamous cell carcinoma (ESCC) in high-incidence areas of China, Iran and Brazil, but PAH assessments have not been conducted in East Africa, another ESCC hot spot.

OBJECTIVE

To evaluate demographic or lifestyle factors associated with the PAH biomarker concentrations in the study population, and whether PAH metabolite concentrations showed any associations with esophageal precancerous lesions.

METHODS

We recruited a community-based sample of 289 asymptomatic adults from a rural area of Kenya and performed Lugol's chromoendoscopy to detect esophageal squamous dysplasia (ESD); participants completed a questionnaire and provided a spot urine specimen. We analyzed urine for seven hydroxylated metabolites of naphthalene, fluorene, phenanthrene, and pyrene at the U.S. National Center for Environmental Health, and compared creatinine-corrected PAH metabolite concentrations with questionnaire data and the presence of ESD.

RESULTS

PAH metabolite concentrations among never tobacco users in these rural Kenya residents were 2.4-28.1 times higher than those reported from never tobacco users in Iran, Brazil and the USA. Female sex, cooking indoors, having no post-primary education, and age <50, but not tobacco use, were positively and significantly associated with PAH metabolite concentrations. Almost all participants used wood as cooking fuel. Nine participants had advanced ESD. Adjusted logistic regression showed a significant association between 2-hydroxynaphthalene (OR = 4.19, 95%CI: 1.01-17.47) and advanced ESD. All other PAH metabolites had positive but non-significant associations with advanced ESD.

CONCLUSIONS

Urinary PAH metabolite concentrations among never tobacco users are markedly higher in this group from Kenya than in other populations and are associated with indoor cooking with wood on open, unvented stoves. These metabolite concentrations were also associated with the presence of advanced esophageal dysplasia. Our findings underline the importance of assessing alternative cooking conditions to reduce PAH exposure in this population.

Referral Patterns of Burn Injury in Rural Kenya

Burn injury represents a substantial burden of disease in resource-limited settings. Kenya has no formal trauma system and referral practices for burn injuries are not well understood. The purpose of this study was to determine the factors associated with burn injury referrals in rural Kenya. A retrospective chart review was conducted for patients with burn injury from January 1, 2014 to December 31, 2017 at a 300-bed faith-based, teaching hospital in southwest Kenya. Bivariate analysis compared referred and non-referred patients. Multivariable logistic regression was used to assess the association between burn severity and odds of referral adjusting for age, sex, insurance, time from injury to arrival, and estimated travel time from home to hospital. The study included 171 patients with burn injury; 11 patients were excluded due to missing referral data. Of the 160 patients, 31.9% (n = 51) were referred. Referral patients had higher average total body surface area burn (23.1 ± 2.4% vs 11.1 ± 1.2%, P < .001), were more likely to have full-thickness burns (41.3% vs 25.5%, P = .05), and less likely to present to the referral hospital within 24 hours after injury (47.8% vs 73.0%, P = .005). Referral patients had longer travel time to hospital (90+ min: 52.9% vs 22.0%, P < .001). Odds of referral increased 1.62 times (95% confidence interval: 1.19-2.22) for every 10% increase in total body surface area burn. Without a coordinated trauma system, referrals represent a substantial portion of burn injury patients at a hospital in rural Kenya. Referred patients present with more severe burns and experience delays to presentation.

Improving Access to Self-Expanding Metal Stents for Patients With Esophageal Cancer in Eastern Africa: A Stepwise Implementation Strategy

PURPOSE

The eastern corridor of Africa is affected by a high burden of esophageal cancer (EC), with > 90% of patients presenting with advanced disease. Self-expanding metal stents (SEMS) have been previously reported as safe and effective for palliation of malignant dysphagia in resource-limited settings; however, access is limited throughout Eastern Africa.

METHODS

In response to demand for palliative interventions for patients with dysphagia because of EC, the African Esophageal Cancer Consortium (AfrECC) partnered with the Clinton Health Access Initiative to improve access to SEMS in Eastern Africa. We undertook a stepwise implementation approach to (1) identify barriers to SEMS access, (2) conduct a market analysis, (3) select an industry partner, (4) establish regulatory and procurement processes, (5) develop endoscopic training resources, (6) create a medical device registry, and (7) establish principles of accountability.

RESULTS

Following an evaluation of market demand and potential SEMS manufacturers, Boston Scientific Corporation announced its commitment to launch an access program to provide esophageal SEMS to patients in Tanzania, Kenya, Malawi, and Zambia at a subsidized price. Parallel regulatory and procurement processes were established in each participating country. Endoscopy training courses were designed and conducted, using the Training-of-Trainers model. A device registry was created to centralize data for quality control and to monitor channels of SEMS distribution. Principles of accountability were developed to guide the sustainability of this endeavor.

CONCLUSION

The AfrECC Stent Access Initiative is an example of a multisector partnership formed to provide an innovative solution to align regional needs with a supply chain for a high-priority medical device.

Optimal management of esophageal cancer in Africa: A systemic review of treatment strategies

Esophageal cancer (EC) is a leading cause of cancer morbidity and mortality in Africa. Despite the high burden of disease, optimal management strategies for EC in resource-constrained settings have yet to be established. This systematic review evaluates the literature on treatments for EC throughout Africa and compares the efficacy and safety of varying treatment strategies in this context (PROSPERO CRD42017071546). PubMed, Embase and African Index Medicus were searched for studies published on treatment strategies for EC in Africa from 1980 to 2020. Searches were supplemented by examining bibliographies of included studies and relevant conference proceedings. Methodological quality/risk of bias was assessed using the Cochrane Risk-of-Bias tool and the Newcastle-Ottawa Scale. Forty-six studies were included. Case series constituted the majority of studies: 13 were case series reporting on outcomes of esophagectomies, 17 on palliative luminal or surgical interventions, four on radiotherapy and three on concurrent chemoradiation. Nine randomized controlled trials were identified, of which four prospectively compared different treatment modalities (one investigating radiotherapy vs chemoradiation, three evaluating rigid plastic stents vs other treatments). This review summarizes the research on EC treatments in Africa published over the last four decades and outlines critical gaps in knowledge related to management in this context. Areas in need of further research include (a) evaluation of the safety and efficacy of neoadjuvant therapy in patients with locally advanced disease; (b) strategies to improve long-term survival in patients treated with definitive chemoradiation; and (c) the comparative effectiveness of modern palliative interventions, focusing on quality of life and survival as outcome measures.

The African Esophageal Cancer Consortium: A Call to Action

Esophageal cancer is the eighth most common cancer worldwide and the sixth most common cause of cancer-related death; however, worldwide incidence and mortality rates do not reflect the geographic variations in the occurrence of this disease. In recent years, increased attention has been focused on the high incidence of esophageal squamous cell carcinoma (ESCC) throughout the eastern corridor of Africa, extending from Ethiopia to South Africa. Nascent investigations are underway at a number of sites throughout the region in an effort to improve our understanding of the etiology behind the high incidence of ESCC in this region. In 2017, these sites established the African Esophageal Cancer Consortium. Here, we summarize the priorities of this newly established consortium: to implement coordinated multisite investigations into etiology and identify targets for primary prevention; to address the impact of the clinical burden of ESCC via capacity building and shared resources in treatment and palliative care; and to heighten awareness of ESCC among physicians, at-risk populations, policy makers, and funding agencies.

Cross sectional study of serum selenium concentration and esophageal squamous dysplasia in western Kenya

Background

Low serum selenium status has been associated with increased risk of esophageal squamous cell carcinoma (ESCC). East Africa is a region of high ESCC incidence and is known to have low soil selenium levels, but this association has not previously been evaluated. In this study we assessed the association of serum selenium concentration and the prevalence of esophageal squamous dysplasia (ESD), the precursor lesion of ESCC, in a cross-sectional study of subjects from Bomet, Kenya.

Methods

294 asymptomatic adult residents of Bomet, Kenya completed questionnaires and underwent endoscopy with Lugol’s iodine staining and biopsy for detection of ESD. Serum selenium concentrations were measured by instrumental neutron activation analysis. Odds ratios (OR) and confidence intervals (95% CI) for associations between serum selenium and ESD were calculated using unconditional logistic regression.

Results

The mean serum selenium concentration was 85.5 (±28.3) μg/L. Forty-two ESD cases were identified (14% of those screened), including 5 (12%) in selenium quartile 1 (Q1), 5 (12%) in Q2, 15 (36%) in Q3, and 17 (40%) in Q4. Higher serum selenium was associated with prevalence of ESD (Q4 vs Q1: OR: 3.03; 95% CI: 1.05–8.74) and this association remained after adjusting for potential confounders (Q4 vs Q1: OR: 3.87; 95% CI: 1.06–14.19).

Conclusion

This is the first study to evaluate the association of serum selenium concentration and esophageal squamous dysplasia in an African population at high risk for ESCC. We found a positive association between higher serum selenium concentration and prevalence of ESD, an association contrary to our original hypothesis. Further work is needed to better understand the role of selenium in the etiology of ESCC in this region, and to develop effective ESCC prevention and control strategies.

Abstract 2766: Esophageal stenting in resource-limited settings

Background: Esophageal cancer is the 6th leading cause of cancer death globally, with geographical high-risk areas in Asia, the Middle East, and eastern and southern Africa. Esophageal squamous cell carcinoma (ESCC) is the more common variant in Africa. In Kenya, its incidence is 2nd in men after prostate cancer and 3rd in women after breast and cervix-uteri cancers. Late presentation is a common occurrence in developing countries and is multifactorial due to challenges in access to health care, low socioeconomic status and delayed or missed diagnosis. A large percentage of these tumors are thus unresectable and are only eligible for palliative care via stenting. Our hospital is a 300-bed referral center in southwestern Kenya, which is a hotspot for ESCC, and we see over 400 cases of ESCC annually.

Methods: We have developed a technique for placement of esophageal self-expanding metallic stents (SEMS) without fluoroscopy that is safe and easily reproducible. This is an outpatient procedure, with the majority done under conscious sedation, and routine followup is not necessary. The tumor margins are noted at time of video endoscopy, a guidewire is placed, and dilation done with Savary dilators as required. The SEMS are then loaded on the stent delivery device and deployed into the proper position based on measurements, and placement is subsequently confirmed via endoscopic visualization.

Results: A total of 3000 SEMS have been placed to date at our hospital, without using fluoroscopy. The male: female ratio has been 1.5:1, and the average age has been 60.4 years. The distribution of tumor locations was 67% in the middle and distal third. The most common complications were tumor overgrowth with obstruction and stent migration. Procedure related mortality was 0.3%. Post-procedure improvement in dysphagia score was seen in over 80% , and patient satisfaction was high. Initial data puts our post stent survival time around 8 months/ 250 days

Conclusions: Placement of SEMS for ESCC, without fluoroscopy, is a safe and reproducible procedure which has a low rate of adverse events. This procedure results in effective palliation of a difficult disease and can easily be done in resource-limited settings which have endoscopy capabilities. Current efforts are ongoing to increase opportunities for training endoscopists in this procedure and for provision of affordable stents in Africa.

Citation Format: Michael M. Mwachiro, Robert K. Parker, Stephen Burgert, Justus Lando, Sinkeet Rankeeti, Robert Chepkwony, Emmanuel Kiniga, Sanford Dawsey, Mark Topazian, Russell E. White. Esophageal stenting in resource-limited settings [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2766. doi:10.1158/1538-7445.AM2017-2766

Esophageal Squamous Dysplasia is Common in Asymptomatic Kenyans: A Prospective, Community-Based, Cross-Sectional Study

OBJECTIVES

Esophageal squamous cell carcinoma (ESCC) is endemic in east Africa and is a leading cause of cancer death among Kenyans. The asymptomatic precursor lesion of ESCC is esophageal squamous dysplasia (ESD). We aimed to determine the prevalence of ESD in asymptomatic adult residents of southwestern Kenya.

METHODS

In this prospective, community-based, cross-sectional study, 305 asymptomatic adult residents completed questionnaires and underwent video endoscopy with Lugol's iodine chromoendoscopy and mucosal biopsy for detection of ESD.

RESULTS

Study procedures were well tolerated, and there were no adverse events. The overall prevalence of ESD was 14.4% (95% confidence interval (CI): 10-19%), including 11.5% with low-grade dysplasia and 2.9% with high-grade dysplasia. The prevalence of ESD was >20% among men aged >50 years and women aged >60 years. Residence location was significantly associated with ESD (Zone A adjusted odds ratio (OR) 2.37, 95% CI: 1.06-5.30 and Zone B adjusted OR 2.72, 95% CI: 1.12-6.57, compared with Zone C). Iodine chromoendoscopy with biopsy of unstained lesions was more sensitive than white-light endoscopy or random mucosal biopsy for detection of ESD and had 67% sensitivity and 70% specificity.

CONCLUSIONS

ESD is common among asymptomatic residents of southwestern Kenya and is especially prevalent in persons aged >50 years and those living in particular local regions. Lugol's iodine chromoendoscopy is necessary for detection of most ESD but has only moderate sensitivity and specificity in this setting. Screening for ESD is warranted in this high-risk population, and endoscopic screening of Kenyans is feasible, safe, and acceptable, but more accurate and less invasive screening tests are needed.

Randomized Trial of Small-diameter Versus Large-diameter Esophageal Stents for Palliation of Malignant Esophageal Obstruction

GOALS

To assess the effect of esophageal stent diameter on outcomes of patients with malignant esophageal obstruction.

BACKGROUND

Esophageal self-expandable metal stents (SEMS) effectively palliate dysphagia due to malignancy, but the best stent diameter is unknown.

STUDY

A prospective randomized trial was conducted at a regional referral hospital. One hundred persons with unresectable esophageal cancer were enrolled, randomized to receive a SEMS of either 18 or 23 mm shaft diameter but identical design, and followed until death. Outcome measurements were dysphagia score, adverse events, endoscopic reintervention, and survival.

RESULTS

The study arms were evenly matched. Dysphagia resolved after stent placement in 95% in both groups. After 6 months the cumulative incidence of recurrent dysphagia was 38% (95% CI 18%-53%) versus 47% (26%-63%) in the small-diameter versus large-diameter groups, respectively (P=0.23). The cumulative incidence of adverse events was 57% in both groups at 6 months, with trends toward more frequent gastrointestinal bleeding and esophago-respiratory fistula in the large-diameter group, and more frequent stent migration, stent occlusion, and endoscopic reintervention in the small-diameter group. There was a trend toward longer survival in the small-diameter group (median survival, 5.9 vs. 3 mo; P=0.10). Higher initial performance status score and female gender were associated with improved survival. Limitations include enrollment of only 100 (of a planned 200) persons and incomplete follow-up of some participants.

CONCLUSIONS

Small-diameter and large-diameter esophageal SEMS provided similar palliation of dysphagia due to esophageal cancer. The overall incidence of adverse events was not affected by stent diameter, but there was a trend toward longer survival with small-diameter stents (Clinical trial registration number: NCT01894763).

Safe handling of cytotoxics: guideline recommendations

BACKGROUND

This evidence-based practice guideline was developed to update and address new issues in the handling of cytotoxics, including the use of oral cytotoxics; the selection and use of personal protective equipment; and treatment in diverse settings, including the home setting.

METHODS

The guideline was developed primarily from an adaptation and endorsement of an existing guideline and from three systematic reviews. Before publication, the guideline underwent a series of peer and external reviews to gather feedback. All comments were addressed, and the guideline was amended when required. The guideline applies to health care workers who could come into contact with cytotoxic drugs at any point in the medication circuit. The intended users are hospital administrators, educators, and managers; occupational health and safety services; and pharmacy and health care workers.

RESULTS

The recommendations represent a reasonable and practical set of procedures that the intended users of this guideline should implement to minimize opportunities for accidental exposure. They are not limited to just the point of care; they cover the entire chain of cytotoxics handling from the time such agents enter the institution until they leave in the patient or as waste.

CONCLUSIONS

Reducing the likelihood of accidental exposure to cytotoxic agents within the medication circuit is the main objective of this evidenced-based guideline. The recommendations differ slightly from earlier guidelines because of the availability of new evidence.

Hyperhomocysteinemia is detrimental to pregnancy in mice and is associated with preterm birth

Elevated levels of homocysteine produce detrimental effects in humans but its role in preterm birth is not known. Here we used a mouse model of hyperhomocysteinemia to examine the relevance of homocysteine to preterm birth. The mouse carries a heterozygous deletion of cystathionine β-synthase (Cbs(+/-)). Gestational period was monitored in wild type and Cbs(+/-) female mice. Mouse uterine and placental tissues, human primary trophoblast cells, and human myometrial and placental cell lines were used to determine the influence of homocysteine on expression of specific genes in vitro. The activity of BKCa channel in the myometrial cell line was monitored using the patch-clamp technique. We found that hyperhomocysteinemia had detrimental effects on pregnancy and induced preterm birth in mice. Homocysteine increased the expression of oxytocin receptor and Cox-2 as well as PGE2 production in uterus and placenta, and initiated premature uterine contraction. A Cox-2 inhibitor reversed these effects. Gpr109a, a receptor for niacin, induced Cox-2 in uterus. Homocysteine upregulated GPR109A and suppressed BKCa channel activity in human myometrial cells. Deletion of Gpr109a in Cbs(+/-) mice reversed premature birth. We conclude that hyperhomocysteinemia causes preterm birth in mice through upregulation of the Gpr109a/Cox-2/PGE2 axis and that pharmacological blockade of Gpr109a may have potential in prevention of preterm birth.

Alcohol and acetaldehyde in African fermented milk mursik--a possible etiologic factor for high incidence of esophageal cancer in western Kenya

BACKGROUND

Esophageal cancer is unusually frequent in Western Kenya, despite the low prevalence of classical risk factors such as heavy drinking and tobacco smoking. Among Kenyans consumption of fermented milk is an old tradition. Our hypothesis is that alcohol and acetaldehyde are produced during the fermentation process and that their carcinogenic potential contributes to the high incidence of esophageal cancer.

METHODS

Eight samples of mursik milk starter cultures were collected from different Kalenjin families in the Rift Valley province, Western Kenya. A protocol provided by the families was used for milk fermentation. Ethanol and acetaldehyde levels were measured by gas chromatography. The microbial flora in starter cultures was identified by 16S and 18S sequencing.

RESULTS

7/8 starter cultures produced mutagenic (>100 μmol/L) levels of acetaldehyde and 4/8 starter cultures produced more than 1,000 μmol/L of acetaldehyde. The highest alcohol levels (mean 79.4 mmol/L) were detected in the four fermented milks with highest acetaldehyde production. The mean number of microbial species in the starter cultures was 5 (range 2-8). Yeasts were identified in all starter cultures (mean 1.5 species/milk) but their proportion of the total microbial count varied markedly (mean 35%, range 7%-90%). A combination of yeast and lactobacilli, especially Candida krusei with Lactobacillus kefiri, with the exclusion of other species, seemed to correlate with higher acetaldehyde and ethanol levels.

CONCLUSIONS

Significant levels of ethanol and acetaldehyde were produced during mursik fermentation.

IMPACT

When ingested several times daily the repeated exposure to carcinogenic levels of acetaldehyde may contribute to esophageal carcinogenesis.

Stents for proximal esophageal cancer: a case-control study

BACKGROUND

Self-expandable metal stents (SEMSs) are an established palliative therapy for esophageal cancer. SEMS placement for cancers near the upper esophageal sphincter (UES) is controversial because of a perceived increased risk of complications.

OBJECTIVE

To compare outcomes after patients stented for proximal esophageal cancer (PC) and distal esophageal cancer (DC).

DESIGN

Matched case-control study from a prospective database.

SETTING

Tertiary referral center, Tenwek Hospital, Bomet, Kenya.

PATIENTS

All patients with PC located within 6 cm of the UES were matched with randomly selected controls with DC.

INTERVENTIONS

Outcomes of PC cases were compared with those of DC controls.

MAIN OUTCOME MEASUREMENTS

Dysphagia score, complications, median survival.

RESULTS

A total of 151 patients with PC were identified and were randomly matched with DC controls. Ninety-three case-control pairs had adequate follow-up information available. Mean dysphagia scores (scale 0-4) improved from 3.4 and 3.3 before stenting for PC and DC, respectively, to 1.5 after stenting for both groups (P = .93). Early complications occurred in 6.5% of PC cases and 9.7% of DC controls (P = .44). Late complications occurred in 20.4% of PC cases and 15.1% of DC controls (P = .25). Median survival was 210 days for PC cases and 272 days for DC controls (P = .25). Outcomes were similar for the subgroup of PC cases whose cancer extended to within 2 cm of the UES.

LIMITATION

An important limitation is the absence of adequate follow-up data for 58 of the 151 case-control pairs.

CONCLUSIONS

SEMSs effectively palliate dysphagia in PC cases, whereas complication and survival rates are not statistically different from those of DC controls.

Esophageal cancer in young people: a case series of 109 cases and review of the literature

Certain geographically distinct areas of the world have very high rates of esophageal cancer (EC). Previous studies have identified western Kenya as a high risk area for EC with an unusual percentage of cases in subjects 30 years of age or younger. To better understand EC in these young patients, we abstracted available data on all 109 young patients diagnosed with EC at Tenwek Hospital, Bomet District, Kenya from January 1996 through June 2009, including age at diagnosis, sex, ethnicity, tumor histology, residence location, and medical interventions. We also attempted to contact all patients or a family member and obtained information on ethnicity, tobacco and alcohol use, family history of cancer, and survival. Sixty (55%) representatives of the 109 young patients were successfully interviewed. The median survival time of these 60 patients was 6.4 months, the most common tumor histology was esophageal squamous cell carcinoma (ESCC) (98%), the M:F ratio was 1.4∶1, and only a few subjects used tobacco (15%) or alcohol (15%). Seventy-nine percent reported a family history of cancer and 43% reported having a family history of EC. In summary, this case series describes the largest number of young EC patients reported to date, and it highlights the uniqueness of the EC experience in western Kenya.

Frequent occurrence of esophageal cancer in young people in western Kenya

Esophageal cancer has a strikingly uneven geographical distribution, resulting in focal endemic areas in several countries. One such endemic area is in western Kenya. We conducted a retrospective review of all pathology-confirmed malignancies diagnosed at Tenwek Hospital, Bomet District, between January 1999 and September 2007. Tumor site, histology, sex, age, ethnicity, and location of residence were recorded. Cases were analyzed within and outside a traditional catchment area defined as < or = 50 km from the hospital. Since 1999, the five most common cancer sites were the esophagus, stomach, prostate, colorectum, and cervix. Esophageal cancer accounted for 914 (34.6%) of the 2643 newly diagnosed cancers and showed increasing trends within and outside the catchment area. Fifty-eight (6.3%) patients were < or = 30 years old and 9 (1%) were < or = 20 years old; the youngest patient was 14 years at diagnosis. Young cases (< or = 30) were more common among patients of Kalenjin ethnicity (9.2%) than among other ethnicities (1.7%) (odds ratio [95% confidence interval] 5.7 [2.1-15.1]). This area of western Kenya is a high-risk region for esophageal cancer and appears unique in its large proportion of young patients. Our findings support the need for further study of both environmental and genetic risk factors for esophageal cancer in this area.

Association between migraine, anxiety and depression

Logistic regression was used to evaluate the relationship between self-reported medical diagnosis of migraine, self-reported depressive symptomology (RDS) and self-reported anxious symptomology (RAS) in the National Health Interview Survey ( n = 30 852). Semipartial squared correlations evaluated the population-level variability between RDS, RAS and migraine impairment. Migraine prevalence was 15.2% (overall), 20.5% (women) and 9.4% (men). Migraine risk was higher in participants with RAS [odds ratio (OR) 2.30, 95% confidence interval (CI) 2.09, 2.52), with RDS (OR 2.23, 95% CI 1.93, 2.58), who smoked (OR 1.19, 95% CI 1.09, 1.30), or who consulted a mental health provider (OR 1.45, 95% CI 1.27, 1.65). Although migraine risk was increased in both women (OR 1.93) and men (OR 2.42) with RAS ( P < 0.001), men with RAS had a higher migraine risk than did women with RAS ( P < 0.001). Only 7% of the variability in migraine impairment (population level) was predicted by variability in RDS and/or RAS.

Stents as sole therapy for oesophageal cancer: a prospective analysis of outcomes after placement

BACKGROUND

Therapies for inoperable oesophageal cancer include chemoradiotherapy and placement of a self-expanding metal stent (SEMS). Few data are available regarding SEMS as sole therapy for patients with inoperable disease who have not already received, or are unfit for, chemoradiotherapy. The aim of this study was to determine survival, adequacy of palliation, and complications after SEMS placement as sole therapy for inoperable oesophageal cancer in a resource-limited setting.

METHODS

Data were prospectively gathered on all patients with oesophageal cancer treated with SEMS between Jan 1, 1999, and May 20, 2008, at a hospital in Kenya where chemoradiotherapy is unavailable. Dysphagia scores, morbidity, mortality, and survival were assessed. Follow-up was done during clinic visits, home visits, and by mobile phone.

FINDINGS

1000 stents were placed in 951 patients. Long-term follow-up was obtained for 334 patients (35%) with a median survival of 250 days (IQR 130-431, 95%CI 217-301). Mean dysphagia scores improved from 3.3 (SD 0.6) pre-SEMS (n=697) to 1.0 (SD 1.3) for patients (n=78) still alive and 1.8 (SD 1.2) at time of death (n=165). Survival of 17 patients with follow-up who had perforation during tumour dilation (treated with SEMS) was 283 days (IQR 227-538) similar to the 317 patients with follow-up data who did not have a perforation (245 days, 124-430). 20 patients with a tracheo-oesophageal fistula lived a median of 142 days (IQR 73-329). Early complications occurred in 6% (54 of 951 patients) and late complications occurred in 19% (62 of 334 patients). SEMS-related mortality was 0.3% (three of 951).

INTERPRETATION

SEMS effectively palliate inoperable oesophageal cancer. Survival may be longer than previously reported when SEMS are placed in all patients with inoperable oesophageal cancer, as in our study, rather than those failing or unfit for chemoradiotherapy. SEMS seem to be an appropriate technology for palliation of oesophageal cancer in resource-limited settings. Given the proportion of patients lost to follow up, these findings merit further confirmation.

Two Epstein-Barr virus (EBV) oncoproteins cooperate to repress expression of the proapoptotic tumour-suppressor Bim: clues to the pathogenesis of Burkitt's lymphoma

Epstein-Barr virus (EBV) contributes to the development of several human cancers including the endemic form of Burkitt's lymphoma (BL). In culture, EBV induces the continuous proliferation of primary B cells as lymphoblastoid cell lines (LCLs) and if EBV-negative BL-derived cells are infected with EBV, latency-associated viral factors confer resistance to various inducers of apoptosis. Nuclear proteins EBNA3A and EBNA3C (but not EBNA3B) are necessary to establish LCLs and their expression may be involved in the resistance of BL cells to cytotoxic agents. We have therefore created recombinant EBVs from which each of the EBNA3 genes has been independently deleted, and revertant viruses in which the genes have been re-introduced into the viral genome. Infection of EBV-negative BL cells with this panel of EBVs and challenge with various cytotoxic drugs showed that EBNA3A and EBNA3C cooperate as the main determinants of both drug resistance and the downregulation of the proapoptotic Bcl-2-family member Bcl-2-interacting mediator of cell death (Bim). The regulation of Bim is predominantly at the level of RNA, with little evidence of post-translational Bim stabilization by EBV. In the absence of Bim, EBNA3A and EBNA3C appear to provide no survival advantage. The level of Bim is a critical regulator of B cell survival and reduced expression is a major determinant of lymphoproliferative disease in mice and humans; moreover, Bim is uniquely important in the pathogenesis of BL. By targeting this tumour-suppressor for repression, EBV significantly increases the likelihood of B lymphomagenesis in general, and BL in particular. Our results may also explain the selection pressure that gives rise to a subset of BL that retain expression of the EBNA3 proteins.

Absence of human papillomavirus in esophageal carcinomas from southwestern Kenya

Esophageal squamous cell cancer is highly prevalent in south-western Kenya. The role of human papillomavirus (HPV) in esophageal cancers from this region was evaluated. Biopsies of 29 esophageal squamous cell cancers were assayed for HPV DNA sequences by reverse line blot polymerase chain reaction, using 27 HPV type-specific probes. Viral sequences were found in none of the specimens. These results suggest the HPV is unlikely to be an etiologic factor for esophageal squamous cell cancers in this region.

Expandable stents for iatrogenic perforation of esophageal malignancies

The management of patients with iatrogenic perforation of esophageal cancers is controversial. We reviewed the management of perforated esophageal malignancies at a single institution with a large volume of patients with esophageal cancer. Cases of iatrogenic perforation of the esophagus occurring during a 3-year period were identified from the hospital endoscopy database. Inpatient and outpatient records were reviewed, and subjects were visited to obtain follow-up information. Perforation was suspected after 10 of 492 endoscopic dilatation procedures done in patients with obstructing esophageal malignancies. All patients were diagnosed immediately. One patient with pneumomediastinum and pneumoperitoneum died 7 days after laparotomy. Nine patients with pneumomediastinum were managed endoscopically with delayed (n=1) or immediate (n=8) placement of a self-expanding metal stent. Patients were treated in the hospital for an average of 5.4 days. No patients developed clinical signs of sepsis, and all were discharged tolerating a soft diet. Follow-up data were obtained for seven of nine discharged patients (range 152 to 263 days). None developed signs or symptoms of infection or recurrent dysphagia. Immediate placement of a coated self-expanding metal stent is an effective treatment for iatrogenic perforation of an obstructing esophageal malignancy.

Oxidative activation of acylguanidine prodrugs: intestinal presystemic activation in rats limits absorption and can be inhibited by co-administration of ketoconazole

1. The disposition of acyl prodrugs was studied to improve the delivery of a guanidine-containing parent compound with poor membrane permeability and poor absorption. 2. The prodrugs were evaluated in vitro and in vivo for conversion to drug. Prodrugs were evaluated for hydrolytic or oxidative bioactivation in intestinal homogenate and rat liver S9 or microsomes. The disposition of the prodrugs in vivo was monitored in bile duct-cannulated rats. 3. Compounds with n-alkylacyl groups were efficiently bioactivated, but were hydrolysed before absorption. 4. Hydrolytic bioactivation could be blocked in vitro by branching in the alkyl chain. These compounds showed modest improvements in absorption, despite favourable permeability. Experiments with liver microsomes demonstrated efficient NADPH-dependent oxidative bioactivation, which was proposed to occur through a CYP-mediated side chain oxidation followed by cyclization and release of parent compound. Ketoconazole co-administration yielded approximately a twofold increase in absorption. 5. The hydrolytically stable prodrugs were successful in increasing absorption of parent drug and were efficiently bioactivated, but they did not yield increased systemic levels of drug.

Sorption and degradation characteristics of phosmet in two contrasting Australian soils

The organophosphate insecticide phosmet [phosphorodithioic acid, s-((1,3-dihydro-1,3-dioxo-2H-isoindol-2yl)methyl), o,o-dimethyl ester] is used to control red-legged earth mites (Halotydeus destructor), lucerne flea (Sminthurus viridis), and Oriental fruit moth (Cydia molesta) in horticulture and vegetable growing. This study was undertaken with two soils of contrasting properties to determine the extent to which sorption and degradation of the insecticide might influence its potential to leach from soil into receiving waters. Two soils were used: a highly organic, oxidic clay soil (Ferrosol) and a sandy soil low in organic matter (Podosol), sampled to 0.3 m depth. The extent of sorption and decomposition rate of a phosmet commercial formulation were measured in laboratory experiments. Sorption followed a Freundlich isotherm at all depths. The Freundlich coefficient K was significantly correlated (p = 0.005) with organic C content in the Podosol, and significantly correlated (p = 0.005) with organic C and clay content in the Ferrosol. K was highest (48.8 L kg-1) in the 0- to 0.05-m depth of the Ferrosol, but lowest (1.0 L kg-1) at this depth in the Podosol. Degradation followed first-order kinetics, with the phosmet half-life ranging from 14 h (0-0.05 m depth) to 187 h (0.2-0.3 m depth) in the Ferrosol. The half-life was much longer in the sandy Podosol, ranging from 462 to 866 h, and did not change significantly with depth. Soil organic C and to a lesser degree clay content influenced phosmet sorption and degradation, but the interaction was complex and possibly affected by co-solvents present in the commercial formulation.

Oesophageal cancer: a common malignancy in young people of Bomet District, Kenya

Oesophageal cancer is a common cancer with uneven geographical distribution. We reviewed all malignancies diagnosed at Tenwek Hospital (Bomet District, Kenya) between 1989 and 1998. Oesophageal cancer was the most common malignancy; 274 cases accounted for 19% of 1459 malignancies diagnosed, and for a steady rise in total cancer cases during this period. A striking feature of our study was the presence of a subset of very young patients. 26 (11%) patients were aged 30 years or less at diagnosis, and the youngest patient was 14 years old. This area of West Kenya seems to be a high-risk region for oesophageal cancer.

Effect of posterior capsular repair on early dislocation in primary total hip replacement

Formal repair of the posterior capsule and short external rotator tendons has been described as a surgical approach to reduce the incidence of posterior dislocation after posterolateral surgical approach to primary total hip replacement. The purpose of the current study was to compare the incidence of early posterior dislocation (within the first 6 months after surgery) using a complete posterior capsulectomy versus a formal posterior capsular repair. In patients with a complete posterior capsulectomy, 52 of 1078 primary total hip replacements (4.8%) had an early posterior dislocation. In patients with posterior capsular repair, three of 437 primary total hip replacements (0.7%) had an early posterior dislocation. This difference was statistically significant. The only complication in the capsular repair group was an avulsion fracture of the greater trochanter in four of 437 total hip replacements (0.9%).

Direct simultaneous analysis of plasma samples for a drug discovery compound and its hydroxyl metabolite using mixed-function column liquid chromatography-tandem mass spectrometry

A polymer-coated mixed-function (PCMF) column was evaluated for direct plasma injection for the simultaneous determination of a drug candidate and its hydroxyl metabolite by high-performance liquid chromatography (HPLC) with tandem mass spectrometry (MS-MS) in support of pharmacokinetic studies. Each diluted monkey plasma sample containing internal standard was directly injected on to the PCMF column for sample clean-up, enrichment and chromatographic separation. The proteins and macromolecules were first eluted from the column while the drug molecules were retained on the bonded hydrophobic phase. The analytes retained on the column were then eluted with a strong mobile phase using a gradient separation technique at a constant flow rate of 1.0 ml min(-1). When not diverted, the column effluent was connected either to the atmospheric pressure chemical ionization (APCI) source or the electrospray ionization (ESI) source as part of the mass spectrometer system used for quantification. The calibration curve was linear over the range 5-2500 ng ml(-1) for both analytes. The retention times for the analytes and the internal standard were both consistent and no column deterioration was observed for at least 500 injections. The recovery through the column and reproducibility of the dosed compound and its hydroxyl metabolite in monkey plasma samples were > 90% (RSD < 6%). The total analysis time was < 8 min per sample. The analytical results obtained by the proposed direct plasma injection method were in good agreement with those obtained by the conventional LC-MS-MS method.

Sequences adjacent to oriP improve the persistence of Epstein-Barr virus-based episomes in B cells

Epstein-Barr virus (EBV) oriP and the EBV nuclear antigen 1 (EBNA-1) protein allow persistence of EBV-based episomes. A nuclear matrix attachment region (MAR) spans oriP and the adjacent region of the EBV genome containing the EBV-expressed RNAs. Here, we show that episomes with the MAR are retained significantly more efficiently in EBV-positive B cells than episomes containing oriP alone.

Epoxyeicosatrienoic acid-induced relaxation is impaired in insulin resistance

We assessed the effect of epoxyeicosatrienoic acids (EETs) in intact mesenteric arteries and Ca(2+)-activated K(+) (BK(Ca)) channels of isolated vascular smooth muscle cells from control and insulin-resistant (IR) rats. The response to 11,12-EET and 14,15-EET was assessed in small mesenteric arteries from control and IR rats in vitro. Mechanistic studies were performed in endothelium intact or denuded arteries and in the presence of pharmacological inhibitors. Moreover, EET-induced activation of the BK(Ca) channel was assessed in myocytes in both the cell-attached and the inside-out (I/O) patch-clamp configurations. In control arteries, both EET isomers induced relaxation. Relaxation was impaired by endothelium denudation, N(omega)-nitro-L-arginine, or iberiotoxin (IBTX), whereas it was abolished by IBTX + apamin or charybdotoxin + apamin. In contrast, the EETs did not relax IR arteries. In control myocytes, the EETs increased BK(Ca) activity in both configurations. Conversely, in the cell-attached mode, EETs had no effect on BK(Ca) channel activity in IR myocytes, whereas in the I/O configuration, BK(Ca) channel activity was enhanced. EETs induce relaxation in small mesenteric arteries from control rats through K(Ca) channels. In contrast, arteries from IR rats do not relax to the EETs. Patch-clamp studies suggest impaired relaxation is due to altered regulatory mechanisms of the BK(Ca) channel.

Testosterone relaxes coronary arteries by opening the large-conductance, calcium-activated potassium channel

Cardiovascular diseases are often considered to be a predominantly male health problem, and it has been suggested that testosterone exerts deleterious effects on cardiovascular function; however, few experimental studies support this suggestion. Moreover, the cellular and molecular mechanism(s) underlying vascular responses to testosterone is unknown. The present study has investigated the acute effects of testosterone on porcine coronary artery smooth muscle at the tissue and cellular levels. Contractile studies demonstrated that testosterone or dihydrotestosterone (a nonaromatizable metabolite) relaxed these arteries by an endothelium-independent mechanism involving potassium efflux. Direct evidence from patch-clamp studies confirmed that testosterone opened K(+) channels in single coronary myocytes, and further analysis identified this protein as the large-conductance, calcium- and voltage-activated potassium (BK(Ca)) channel. Moreover, inhibiting BK(Ca) channel activity significantly attenuated testosterone-induced coronary relaxation. These findings indicate that testosterone relaxes porcine coronary arteries predominantly by opening BK(Ca) channels in coronary myocytes, and this response may be associated with accumulation of cGMP. This novel mechanism may provide a better understanding of testosterone-induced vasorelaxation reported in recent experimental and early clinical studies.

Pharmacokinetic theory of cassette dosing in drug discovery screening

Cassette dosing is a procedure for higher-throughput screening in drug discovery to rapidly assess pharmacokinetics of large numbers of candidate compounds. In this procedure, multiple compounds are administered simultaneously to a single animal. Blood samples are collected, and the plasma samples obtained are analyzed by means of an assay method such as liquid chromatography coupled to tandem mass spectrometry that permits concurrent assay of many compounds in a single sample. Consequently, the pharmacokinetics of multiple compounds can be assessed rapidly with a small number of experimental animals and with shortened assay times. However, coadministration of multiple compounds may result in pharmacokinetic drug-drug interactions. This paper describes a pharmacokinetic description for cassette dosing derived from pharmacokinetic theory. The most important finding from this theoretical treatment is that the potential for drug-drug interactions leading to altered clearances of coadministered drugs depends on both the relative K(M) values for the metabolic enzymes and the total number of drugs coadministered. However, the theory predicts that the potential for drug-drug interactions is only a weak function of the dose size. Finally, it is also shown that including a benchmark compound within the set of coadministered compounds cannot ensure the detection of errors due to drug-drug interactions. Thus, neither the absolute values of pharmacokinetic parameters nor the rank order obtained from cassette dosing can be accepted without independent confirmation. These theoretical predictions are evaluated with data taken from the literature.

Resection arthroplasty for nonseptic failure of total hip arthroplasty

Although resection arthroplasty is a well-recognized salvage procedure for septic total hip arthroplasty, the nonseptic complications of total hip arthroplasty are customarily handled by revision and replacement of a new total hip implant. Some of the severe forms of failure of total hip arthroplasty in the absence of infection may require resection arthroplasty. The indication is massive loss of available bone stock for the revision operation. This may result from technical errors or progressive and extensive destruction of bone associated with loosened components. Concern for this outcome is important for assessing the probabilities of long-term success of the use of total hip arthroplasty in young patients.