Monotone and near-monotone biochemical networks

Monotone subsystems have appealing properties as components of larger networks, since they exhibit robust dynamical stability and predictability of responses to perturbations. This suggests that natural biological systems may have evolved to be, if not monotone, at least close to monotone in the sense of being decomposable into a “small” number of monotone components, In addition, recent research has shown that much insight can be attained from decomposing networks into monotone subsystems and the analysis of the resulting interconnections using tools from control theory. This paper provides an expository introduction to monotone systems and their interconnections, describing the basic concepts and some of the main mathematical results in a largely informal fashion

Pooled analysis of WHO Surgical Safety Checklist use and mortality after emergency laparotomy

Background The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89.6 per cent) compared with that in countries with a middle (753 of 1242, 60.6 per cent; odds ratio (OR) 0.17, 95 per cent c.i. 0.14 to 0.21, P <0001) or low (363 of 860, 422 per cent; OR 008, 007 to 010, P <0.001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference -94 (95 per cent c.i. -11.9 to -6.9) per cent; P <0001), but the relationship was reversed in low-HDI countries (+121 (+7.0 to +173) per cent; P <0001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0.60, 0.50 to 073; P <0.001). The greatest absolute benefit was seen for emergency surgery in low- and middle-HDI countries. Conclusion Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries.Peer reviewe

Global variation in anastomosis and end colostomy formation following left-sided colorectal resection

Background End colostomy rates following colorectal resection vary across institutions in high-income settings, being influenced by patient, disease, surgeon and system factors. This study aimed to assess global variation in end colostomy rates after left-sided colorectal resection. Methods This study comprised an analysis of GlobalSurg-1 and -2 international, prospective, observational cohort studies (2014, 2016), including consecutive adult patients undergoing elective or emergency left-sided colorectal resection within discrete 2-week windows. Countries were grouped into high-, middle- and low-income tertiles according to the United Nations Human Development Index (HDI). Factors associated with colostomy formation versus primary anastomosis were explored using a multilevel, multivariable logistic regression model. Results In total, 1635 patients from 242 hospitals in 57 countries undergoing left-sided colorectal resection were included: 113 (6·9 per cent) from low-HDI, 254 (15·5 per cent) from middle-HDI and 1268 (77·6 per cent) from high-HDI countries. There was a higher proportion of patients with perforated disease (57·5, 40·9 and 35·4 per cent; P < 0·001) and subsequent use of end colostomy (52·2, 24·8 and 18·9 per cent; P < 0·001) in low- compared with middle- and high-HDI settings. The association with colostomy use in low-HDI settings persisted (odds ratio (OR) 3·20, 95 per cent c.i. 1·35 to 7·57; P = 0·008) after risk adjustment for malignant disease (OR 2·34, 1·65 to 3·32; P < 0·001), emergency surgery (OR 4·08, 2·73 to 6·10; P < 0·001), time to operation at least 48 h (OR 1·99, 1·28 to 3·09; P = 0·002) and disease perforation (OR 4·00, 2·81 to 5·69; P < 0·001). Conclusion Global differences existed in the proportion of patients receiving end stomas after left-sided colorectal resection based on income, which went beyond case mix alone

Alterações citopatológicas e fatores de risco para a ocorrência do câncer de colo uterino Alteraciones citopatológicas y factores de riesgo para la ocurrencia del cáncer de cuello de útero Citopathological alterations and risk factors for uterine cervical neoplasm

O objetivo do estudo foi verificar alterações citopatológicas e fatores de risco para o câncer de colo uterino em mulheres usuárias do Sistema Único de Saúde de um município de pequeno porte do norte do Paraná, de 2001 a 2006. Trata-se de um estudo observacional transversal descritivo. A coleta de dados foi realizada com os resultados dos exames, prontuários e entrevistas. Foram realizados 6.356 exames e 65(1,02%) apresentaram alterações. Dos exames realizados, 4.869 (70,8%) foram em mulheres de 25 a 59 anos. 38,5% dos exames apresentaram Neoplasia Intraepitelial Cervical (NIC) I, 32,3% NIC II e 18,5% NIC I e Papiloma Vírus Humano (HPV). Foram entrevistadas 25 mulheres, a maioria apresentou algum fator de risco como: tabagismo, doenças sexualmente transmissíveis, uso de anticoncepcional hormonal, número de parceiros, início precoce da atividade sexual. Conclui-se pela necessidade de ações educativas mais efetivas no sentido de reduzir as alterações principalmente entre as mulheres adolescentes.<br>El objetivo del estudio fue verificar alteraciones citopatológicas y factores de riesgo para la ocurrencia del cáncer de cuello de útero en mujeres atendidas por el Sistema Único de la Salud de una ciudad de pequeño porte en la Región Norte de la Provincia del Paraná, Brasil en el período de 2001 al 2006. Se trata de un estudio observacional transversal descriptivo. La colección de los datos fue realizada con los resultados de los exámenes, prontuarios y entrevistas. Fueron realizados 6.356 exámenes y 65(1,02%) presentaron alteraciones. De los exámenes hechos 4.869 (70,8%) fue compuesto de mujeres con edad entre los 25 a los 59 años. Un total de 38,5% de los exámenes presentaron Neoplasia Intra-epitelial del Cuello Uterino (NIC) I, 32,3% NIC II y 18,5% NIC I y Virus de Papiloma Humano (HPV). Fueron entrevistadas 25 mujeres, la mayoría presentó factores de riesgo como: tabaquismo, enfermedades de transmisión sexual, uso de anticonceptivo hormonal, número de parejas sexuales, inicio precoz de la actividad sexual. Concluyese ser necesarias acciones educativas para efectivamente producir la reducción de las alteraciones antes de todo entre mujeres más jóvenes.<br>The aim of the present study was to verify the occurrence of citopathological alterations and risk factors of Uterine Cervical Neoplasm in women attended by SUS - the Public Healthcare System - in a district situated in the North of Paraná State, Brazil from 2001 to 2006. It was a descriptive transversal observational study. The data collection consisted in collection of test results from medical records and interviews. It was achieved 6.356 tests and, 1.02% (65) of the women examined presented alterations. From the tests made 4.869 (70,8%) were from women aged between 25 and 59 years. And 38,5% of the tests presented Cervical Intraepithelial Neoplasm (CIN) I, 32,3% CIN II, 18,5% CIN I and Human Papiloma Virus (HPV). It was interviewed 25 women from the total sample. Most of them presented a risk factor as: smoking habits, sexually transmitted diseases, use of hormonal contraceptive, number of sexual partners, early sexual intercourse. This study concludes that is required educative and more effective actions in order to reduce the alterations, meanly among teenagers