636 research outputs found

    Predicting Phenotypic Diversity and the Underlying Quantitative Molecular Transitions

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    During development, signaling networks control the formation of multicellular patterns. To what extent quantitative fluctuations in these complex networks may affect multicellular phenotype remains unclear. Here, we describe a computational approach to predict and analyze the phenotypic diversity that is accessible to a developmental signaling network. Applying this framework to vulval development in C. elegans, we demonstrate that quantitative changes in the regulatory network can render ~500 multicellular phenotypes. This phenotypic capacity is an order-of-magnitude below the theoretical upper limit for this system but yet is large enough to demonstrate that the system is not restricted to a select few outcomes. Using metrics to gauge the robustness of these phenotypes to parameter perturbations, we identify a select subset of novel phenotypes that are the most promising for experimental validation. In addition, our model calculations provide a layout of these phenotypes in network parameter space. Analyzing this landscape of multicellular phenotypes yielded two significant insights. First, we show that experimentally well-established mutant phenotypes may be rendered using non-canonical network perturbations. Second, we show that the predicted multicellular patterns include not only those observed in C. elegans, but also those occurring exclusively in other species of the Caenorhabditis genus. This result demonstrates that quantitative diversification of a common regulatory network is indeed demonstrably sufficient to generate the phenotypic differences observed across three major species within the Caenorhabditis genus. Using our computational framework, we systematically identify the quantitative changes that may have occurred in the regulatory network during the evolution of these species. Our model predictions show that significant phenotypic diversity may be sampled through quantitative variations in the regulatory network without overhauling the core network architecture. Furthermore, by comparing the predicted landscape of phenotypes to multicellular patterns that have been experimentally observed across multiple species, we systematically trace the quantitative regulatory changes that may have occurred during the evolution of the Caenorhabditis genus

    Schistosomiasis and Urinary Bladder Cancer in North Western Tanzania: A Retrospective Review of 185 Patients.

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    Worldwide, cancers of the urinary bladder are well known to be associated with environmental chemical carcinogens such as smoking and occupational exposure to polycyclic aromatic hydrocarbons. These cancers are typically transitional cell carcinoma (urothelial carcinoma). In areas where schistosomiasis is endemic there is a high incidence of squamous cell carcinoma of the urinary bladder. Schistosomiasis causes chronic granulomatous cystitis leading to squamous metaplasia of transitional epithelium, and subsequently development of squamous cell carcinoma. The western part of Tanzania on the shores of Lake Victoria is such an endemic area. This study was done to document the burden of urinary bladder cancer associated with schistosomiasis in this region. This was a descriptive retrospective study of histologically confirmed cases of urinary bladder cancer seen at the Department of Pathology Bugando Medical Centre (BMC) over a period of 10 years. Data were retrieved from the records of the Departments of Pathology, Medical Records and Surgery. Data were analyzed by the use of contingency tables. A total of 185 patients were diagnosed with cancer of the urinary bladder during the study period, where as 90 (48.6%) were males and 95 (51.4) were females. The mean age at diagnosis was 54.3 years. Squamous cell carcinoma was the most frequent histological type (55.1%), followed by conventional transitional cell carcinoma (40.5%). Eighty three of all cancer cases (44.9%) were found to have schistosomal eggs. Schistosomiasis was commonly associated with squamous cancers compared to non squamous cancers. Most of the cancers associated with schistosomiasis had invaded the muscularis propria of the urinary bladder at the time of diagnosis (p<0.001) and such cancers were frequent below 50 years of age with a significant statistical difference (p<0.001). Poorly differentiated tumors were more frequent in females than males with a significant statistical difference (p=0.006). The majority of urinary bladder cancers seen in the Lake Region were squamous cell carcinoma associated with schistosomiasis. These cancers showed an aggressive behavior and were commonly seen in the younger age groups. Effective control of schistosomiasis in this region should significantly reduce the burden of urinary bladder cancer

    QUANTIFICATION OF RESIDUAL CLOVE OIL, BENZOCAINE AND TRICAINE IN FISH FILLETS USING SPE AND UPLC-DAD

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    Residual quantification of the anesthetics clove oil (CO) – isoeugenol (ISO), eugenol (EUG) and methyleugenol (MET) –,benzocaine (BZN) and tricaine (MS-222) was made in fillets of two fish species: Nile tilapia (Oreochromis niloticus) and acatfish hybrid, cachadia (Pseudoplatystoma reticulatum x Leiarius marmoratus). Samples (n=4) of each fish wereevaluated after submitted to anesthesia in five dosages defined based on the induction time of each species afterdepuration times (0h, 12h, 24h and 48h). Different methodologies of sample preparation were tested and selectedaccording to the better recovery. The quantification of anesthetics was performed by UPLC-DAD. The variance of residualmeans among anesthetics, dosages and fish species was compared. After anesthesia (0h) both species, tilapia andcachadia, presented residual anesthetics. Fishes depurated during 12h, 24h and 48h did not present detectable values, itmeans, values were below the limits of detection. BZN presented the highest mean residual concentration for tilapia andcachadia (p=0.01), while MS-222 presented the lowest residual amounts in tilapias and EUG in cachadias, what may berelated to the metabolism and carcass composition of each fish species. There were no significant differences among thefive dosages, except the lowest MS-222 concentration in tilapias that resulted in higher residual concentrations becauselow dosages increase the induction time and consequently the permanence of the fish in anesthesia. Ultimately, meanvalues of residues in cachadia were higher than in tilapia, and MS-222 and EUG presented the lowest residual values fortilapia and cachadia, respectively

    Operational research in Malawi: making a difference with cotrimoxazole preventive therapy in patients with tuberculosis and HIV.

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    BACKGROUND: In Malawi, high case fatality rates in patients with tuberculosis, who were also co-infected with HIV, and high early death rates in people living with HIV during the initiation of antiretroviral treatment (ART) adversely impacted on treatment outcomes for the national tuberculosis and ART programmes respectively. This article i) discusses the operational research that was conducted in the country on cotrimoxazole preventive therapy, ii) outlines the steps that were taken to translate these findings into national policy and practice, iii) shows how the implementation of cotrimoxazole preventive therapy for both TB patients and HIV-infected patients starting ART was associated with reduced death rates, and iv) highlights lessons that can be learnt for other settings and interventions. DISCUSSION: District and facility-based operational research was undertaken between 1999 and 2005 to assess the effectiveness of cotrimoxazole preventive therapy in reducing death rates in TB patients and subsequently in patients starting ART under routine programme conditions. Studies demonstrated significant reductions in case fatality in HIV-infected TB patients receiving cotrimoxazole and in HIV-infected patients about to start ART. Following the completion of research, the findings were rapidly disseminated nationally at stakeholder meetings convened by the Ministry of Health and internationally through conferences and peer-reviewed scientific publications. The Ministry of Health made policy changes based on the available evidence, following which there was countrywide distribution of the updated policy and guidelines. Policy was rapidly moved to practice with the development of monitoring tools, drug procurement and training packages. National programme performance improved which showed a significant decrease in case fatality rates in TB patients as well as a reduction in early death in people with HIV starting ART. SUMMARY: Key lessons for moving this research endeavour through to policy and practice were the importance of placing operational research within the programme, defining relevant questions, obtaining "buy-in" from national programme staff at the beginning of projects and having key actors or "policy entrepreneurs" to push forward the policy-making process. Ultimately, any change in policy and practice has to benefit patients, and the ultimate judge of success is whether treatment outcomes improve or not

    Cell arrest and cell death in mammalian preimplantation development

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    The causes, modes, biological role and prospective significance of cell death in preimplantation development in humans and other mammals are still poorly understood. Early bovine embryos represent a very attractive experimental model for the investigation of this fundamental and important issue. To obtain reference data on the temporal and spatial occurrence of cell death in early bovine embryogenesis, three-dimensionally preserved embryos of different ages and stages of development up to hatched blastocysts were examined in toto by confocal laser scanning microscopy. In parallel, transcript abundance profiles for selected apoptosis-related genes were analyzed by real-time reverse transcriptase-polymerase chain reaction. Our study documents that in vitro as well as in vivo, the first four cleavage cycles are prone to a high failure rate including different types of permanent cell cycle arrest and subsequent non-apoptotic blastomere death. In vitro produced and in vivo derived blastocysts showed a significant incidence of cell death in the inner cell mass (ICM), but only in part with morphological features of apoptosis. Importantly, transcripts for CASP3, CASP9, CASP8 and FAS/FASLG were not detectable or found at very low abundances. In vitro and in vivo, errors and failures of the first and the next three cleavage divisions frequently cause immediate embryo death or lead to aberrant subsequent development, and are the main source of developmental heterogeneity. A substantial occurrence of cell death in the ICM even in fast developing blastocysts strongly suggests a regular developmentally controlled elimination of cells, while the nature and mechanisms of ICM cell death are unclear. Morphological findings as well as transcript levels measured for important apoptosis-related genes are in conflict with the view that classical caspase-mediated apoptosis is the major cause of cell death in early bovine development

    Polygenic risk score opportunities for early detection and prevention strategies in endometrial cancer

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    From Springer Nature via Jisc Publications RouterHistory: received 2020-04-08, rev-recd 2020-06-03, accepted 2020-06-10, registration 2020-06-12, pub-electronic 2020-07-06, online 2020-07-06, pub-print 2020-09-29Publication status: PublishedSummary: Recent large-scale genetic studies, particularly genome-wide association studies (GWAS), have emphasised the importance of common genetic variation in endometrial cancer susceptibility. Although each of these variants only confer modest effects on endometrial cancer risk, together they are likely to explain a substantial amount of the familial relative risk of the disease. Therefore, methods to combine genetic risk variants, such as polygenic risk scores (PRS) have gained traction as an attractive method for individualised risk prediction and management. Here, we discuss the benefits of a PRS for endometrial cancer and considerations required for clinical implementation

    Assessment of an undergraduate psychiatry course in an African setting

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    <p>Abstract</p> <p>Background</p> <p>International reports recommend the improvement in the amount and quality of training for mental health workers in low and middle income countries. The Scotland-Malawi Mental Health Education Project (SMMHEP) has been established to support the teaching of psychiatry to medical students in the University of Malawi. While anecdotally supportive medical educational initiatives appear of value, little quantitative evidence exists to demonstrate whether such initiatives can deliver comparable educational standards. This study aimed to assess the effectiveness of an undergraduate psychiatry course given by UK psychiatrists in Malawi by studying University of Malawi and Edinburgh University medical students' performance on an MCQ examination paper.</p> <p>Methods</p> <p>An undergraduate psychiatry course followed by an MCQ exam was delivered by the SMMHEP to 57 Malawi medical students. This same MCQ exam was given to 71 Edinburgh University medical students who subsequently sat their own Edinburgh University examination.</p> <p>Results</p> <p>There were no significant differences between Edinburgh students' performance on the Malawi exam and their own Edinburgh University exam. (p = 0.65). This would suggest that the Malawi exam is a comparable standard to the Edinburgh exam. Malawi students marks ranged from 52.4%–84.6%. Importantly 84.4% of Malawi students scored above 60% on their exam which would equate to a hypothetical pass by UK university standards.</p> <p>Conclusion</p> <p>The support of an undergraduate course in an African setting by high income country specialists can attain a high percentage pass rate by UK standards. Although didactic teaching has been surpassed by more novel educational methods, in resource poor countries it remains an effective and cost effective method of gaining an important educational standard.</p

    Plan de negocios para determinar la viabilidad del desarrollo de un asistente virtual de ventas (Chatbot) : caso Gamarra

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    El presente plan de negocios nace de identificar una carencia importante en el emporio comercial de Gamarra: la falta de implementaci?n de herramientas tecnol?gicas que favorezcan sus procesos de venta. As?, la introducci?n de un Asistente Virtual (Chatbot) se presenta como una oportunidad para los empresarios textiles de Gamarra. El an?lisis contextual arroj? que existen circunstancias favorables, a nivel de mercado, para el desarrollo y venta del Asistente Virtual. Sin embargo, tambi?n se destac? que la falta de conocimiento y las barreras de adopci?n tecnol?gica por parte de los empresarios de Gamarra es una barrera importante para el proyecto. Estos datos se consolidaron con los resultados de la investigaci?n de mercado. Empero, los resultados del estudio se?alaron que el empresario textil de Gamarra s? estar?a dispuesto a adquirir el Asistente Virtual, pues lo identifica como ?til para expandir las ventas de su negocio. Para lograr dicho objetivo se desarrollaron planes estrat?gicos, que conclu?an la necesidad de entrar en un mercado no penetrado, creando intimidad con el cliente, educ?ndolo en las bondades de la implantaci?n de tecnolog?a en sus empresas con un producto innovador. Finalmente, las proyecciones financieras se mostraron positivas, generando un VAN de S/259,937 y un TIR de 28%

    Muscle invasive bladder cancer in Upper Egypt: the shift in risk factors and tumor characteristics

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    <p>Abstract</p> <p>Background</p> <p>In Egypt, where bilharziasis is endemic, bladder cancer is the commonest cancer in males and the 2<sup>nd </sup>in females; squamous cell carcinoma (SCC) is the commonest type found, with a peculiar mode of presentation. The aim of this study is to identify and rank the risk factors of muscle invasive bladder cancer (MIBC) in Upper Egypt and describe its specific criteria of presentation and histopathology.</p> <p>Methods</p> <p>This is an analytical, hospital based, case controlled study conducted in south Egypt cancer institute through comparing MIBC cases (n = 130) with age, sex and residence matched controls (n = 260) for the presence of risk factors of MIBC. Data was collected by personal interview using a well designed questionnaire. Patients' records were reviewed for histopathology and Radiologic findings.</p> <p>Results</p> <p>The risk factors of MIBC were positive family history [Adjusted odds ratio (AOR) = 7.7], exposure to pesticides [AOR = 6.2], bladder stones [AOR = 5], consanguinity [AOR = 3.9], recurrent cystitis [AOR = 3.1], bilharziasis [odds ratio (OR) = 5.8] and smoking [OR = 5.3]. SCC represented 67.6% of cases with burning micturition being the presenting symptom in 73.8%.</p> <p>Conclusion</p> <p>MIBC in Upper Egypt is usually of the SCC type (although its percentage is decreasing), occurs at a younger age and presents with burning micturition rather than hematuria. Unlike the common belief, positive family history, parents' consanguinity, exposure to pesticides and chronic cystitis seem to play now more important roles than bilharziasis and smoking in the development of this disease in this area.</p

    The present and future burden of urinary bladder cancer in the world

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    Urinary bladder cancer (UBC) is a common disease worldwide. At any point in time 2.7 million people have a history of UBC. The incidence of UBC varies over the world with highest rates in developed communities. But the burden of UBC will increase in less developed areas of the world. These changes can be attributed to global changes in exposure to risk factors for UBC and growth and aging of the world population
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