253 research outputs found
Exposure to carcinogenic polycyclic aromatic compounds and health risk assessment for diesel-exhaust exposed workers
Objectives: Workers' exposure to diesel exhaust in a bus depot, a truck repair workshop and an underground tunnel was determined by the measuring of elemental carbon (EC) and 15 carcinogenic polycyclic aromatic compounds (PACs) proposed by the US Department of Health and Human Services/National Toxicology Program (NTP). Based on these concentration data, the genotoxic PAC contribution to the diesel-exhaust particle (DEP) lung-cancer risk was calculated. Method: Respirable particulate matter was collected during the summer and winter of 2001 (except for in the underground situation) and analysed by coulometry for EC and by GC-MS methods for PACs. The use of potency equivalence factors (PEFs) allowed the studied PAC concentrations to be expressed as benzo[a]pyrene equivalents (B[a]Peq). We then calculated the lung-cancer risk due to PACs and DEPs by multiplying the B[a]Peq and EC concentrations by the corresponding unit risk factor. The ratio of these two risks values has been considered as an estimate of the genotoxic contribution to the DEP cancer risk. Results: For the bus depot and truck repair workshop, exposure to EC and PACs has been shown to increase by three to six times and ten times, respectively, during winter compared to summer. This increase has been attributed mainly to a decrease in ventilation during the cold. With the PEF approach, the B[a]Peq concentration is five-times higher than if only benzo[a]pyrene (B[a]P) is considered. Dibenzopyrenes contribute an important part to this increase. A simple calculation based on unit risk factors indicates that the studied PAC contribution to the total lung-cancer risk attributed to DEPs is in the range of 3-13%. Conclusions: The 15 NTP PACs represent a small but non-negligible part of lung-cancer risk with regard to diesel exposure. From this point of view, the dibenzopyrene family are important compounds to be considere
Urinary 8-OHdG as a Biomarker for Oxidative Stress: A Systematic Literature Review and Meta-Analysis.
Oxidative stress reflects a disturbance in the balance between the production and accumulation of reactive oxygen species (ROS). ROS are scavenged by the antioxidant system, but when in excess concentration, they can oxidize proteins, lipids, and DNA. DNA damage is usually repaired, and the oxidized products are excreted in urine. 8-hydroxy-2-deoxyguanosine is considered a biomarker for oxidative damage of DNA. It is needed to define background ranges for 8-OHdG, to use it as a measure of oxidative stress overproduction. We established a standardized protocol for a systematic review and meta-analysis to assess background ranges for urinary 8-OHdG concentrations in healthy populations. We computed geometric mean (GM) and geometric standard deviations (GSD) as the basis for the meta-analysis. We retrieved an initial 1246 articles, included 84 articles, and identified 128 study subgroups. We stratified the subgroups by body mass index, gender, and smoking status reported. The pooled GM value for urinary 8-OHdG concentrations in healthy adults with a mean body mass index (BMI) ≤ 25 measured using chemical methods was 3.9 ng/mg creatinine (interquartile range (IQR): 3 to 5.5 ng/mg creatinine). A significant positive association was observed between smoking and urinary 8-OHdG concentrations when measured by chemical analysis. No gender effect was observed
Surgical site infections after pancreatic surgery in the era of enhanced recovery protocols.
Few data exist on risk factors (RF) for surgical site infections (SSI) among patients treated in an enhanced recovery after surgery (ERAS) pathway. This study aimed to assess RF for SSI after pancreas surgery in a non-ERAS group and an ERAS cohort.An exploratory retrospective analysis of all pancreas surgeries prospectively collected (01/2000-12/2015) was performed. RF for SSI were calculated using uni- and multivariable binary logistic regressions in non-ERAS and ERAS patients.Pancreas surgery was performed in 549 patients. Among them, 144 presented a SSI (26%). In the non-ERAS group (n = 377), SSI incidence was 27% (99/377), and RF for SSI were male gender and preoperative biliary stenting. Since 2012, 172 consecutive patients were managed within an ERAS pathway. Forty-five patients (26%) had SSI. On multivariable analysis no RF for SSI in the ERAS cohort was found. In the ERAS group, patients with a pathway compliance ≤70% had higher occurrence of SSI (30/45 = 67% vs. 7/127 = 6%, p < 0.001) and patients with and without SSI had similar median overall compliances (77%, IQR 71-80 vs. 80%, IQR 73-83, p = 0.097).In the non-ERAS cohort, male gender and preoperative biliary stenting were RF for SSI, whereas in the ERAS group no RF for SSI was found. In an ERAS pathway, having an overall compliance >70% might diminish the SSI rate
Impact of Variations in the Nursing Care Supply-Demand Ratio on Postoperative Outcomes and Costs.
Improving surgical outcomes is a priority during the last decades because of the rising economic health care burden. The adoption of enhanced recovery programs has been proven to be part of the solution. In this context, the impact of variations in the nursing care supply-demand ratio on postoperative complications and its economic consequences is still not well elucidated. Because patients require different amounts of care, the present study focused on the more accurate relationship between demand and supply of nursing care rather than the nurse-to-patient ratio.
Through a 3-year period, 838 patients undergoing elective and emergent colorectal and pancreatic surgery within the institutional enhanced recovery after surgery (ERAS) protocol were retrospectively investigated. Nursing demand and supply estimations were calculated using a validated program called the Projet de Recherche en Nursing (PRN), which assigns points to each patient according to the nursing care they need (estimated PRN) and the actual care they received (real PRN), respectively. The real/estimated PRN ratio was used to create 2 patient groups: one with a PRN ratio higher than the mean (PRN+) and a second with a PRN ratio below the mean (PRN-). These 2 groups were compared regarding their postoperative complication rates and cost-revenue characteristics.
The mean PRN ratio was 0.81. A total of 710 patients (84.7%) had a PRN+ ratio, and 128 (15.3%) had a PRN- ratio. Multivariable analysis focusing on overall complications, severe complications, and prolonged length of stay revealed no significant impact of the PRN ratio for all outcomes (P > 0.2). The group PRN- had a mean margin per patient of U.S. dollars 1426 (95% confidence interval, 3 to 2903) compared with a margin of U.S. dollars 676 (95% confidence interval, -2213 to 3550) in the PRN+ group (P = 0.633).
A PRN ratio of 0.8 may be sufficient for patients treated following enhanced recovery after surgery guidelines, pending the adoption of an accurate nursing planning system. This may contribute to better allocation of nursing resources and optimization of expenses on the long run
Закон больших чисел при нарушениях статистической устойчивости
Понятие сходимости последовательности случайных величин обобщено на случай сходимости последовательности гиперслучайных величин. Показано, что закон больших чисел имеет место не только при наличии сходимости выборочного среднего к фиксированному числу, но и тогда, когда такой сходимости нет. Установлено, что выборочное среднее случайной величины может сходиться к фиксированному числу, стремиться к плюс бесконечности, минус бесконечности или флуктуировать в пределах определенного интервала, а выборочное среднее гиперслучайной величины может сходиться к фиксированной величине, множеству фиксированных величин (множеству чисел), флуктуировать в непересекающихся интервалах, флуктуировать в пределах одного интервала или стремиться к плюс или минус бесконечности.Поняття збіжності послідовності випадкових величин узагальнено на випадок збіжності послідовності гіпервипадкових величин. Показано, що закон великих чисел має місце не тільки у разі, коли є збіжність вибіркового середнього до фіксованого числа, але й коли такої збіжності немає. Встановлено, що вибіркове середнє випадкових величин може збігатись до фіксованого числа, прямувати до плюс чи мінус нескінченності або флуктувати в межах інтервалу, а вибіркове середнє гіпервипадкової величини може збігатись до фіксованого числа, множини фіксованих чисел, флуктувати в межах інтервалів, що не перетинаються, флуктувати в межах одного інтервалу або прямувати до плюс чи мінус нескінченності.The term sequence convergence of random quantities has been generalized to the sequence convergence of hyper-random quantities. It has been shown that the low of large numbers for random sequence is correct not only when the average tends to fixed number but in case of the absence of the convergence. It has been found that the average of random variables can approach to the fixed number, tend to plus or minus infinity or fluctuate within the interval and the average of hyper-random variable can approach to the fixed number, to the set of fix numbers, fluctuate within the of disjoint intervals, fluctuate within the single interval or tend to plus or minus infinity
Longterm survey (7 years) in a population at risk for Lyme borreliosis: what happens to the seropositive individuals?
In 1986, a 26% seroprevalence of IgG- anti-Borrelia burgdorferi antibodies was observed among 950 orienteers and the incidence of new clinical infections was 0.8%. In 1993, a total of 305 seropositive orienteers were reexamined. During that time, 15 cases (4.9%) of definite/probable Lyme disease occurred in this seropositive group (12 skin manifestations and 3 monoarticular joint manifestations). Among the 12 definite cases, 9 showed new clinical infections (7 EM, 1 acrodermatitis chronica atrophicans, 1 arthritis), and 3 were recurrent (2 EM, 1 arthritis). The annual incidence (0.8%) in this seropositive group was identical to the incidence observed among the whole population in 1986. The individual antibody titer decreased slightly but the seroreversion rate was low (7%). Serology was not very helpful in identifying clinical cases and evolutions, and it can be stated, that a positive serology is much more frequent in this risk group than clinical disease
The Prevalence and Incidence of Clinical and Asymptomatic Lyme Borreliosis in a Population at Risk
A past history of clinical Lyme borreliosis and the 6-month incidence of clinical and asymptomatic Lyme borreliosis was studied prospectively in a high-risk population. In the spring, blood samples were drawn from 950 Swiss orienteers, who also answered a questionnaire. IgG anti-Borrelia burgdorferi antibodies were detected by ELISA. Positive IgG antibodies were seen in 248 (26.1%), in contrast to 3.9%-6.0% in two groups of controls (n = 101). Of the orienteers, 1.9%-3.1% had a past history of definite or probable clinical Lyme borreliosis. Six months later a second blood sample was obtained from 755 participants, 558 (73.9%) of whom were seronegative initially; 45 (8.1%) had sero converted from negative to positive. Only 1 (2.2%) developed clinical Lyme borreliosis, Among all participants, the 6-month incidence of clinical Lyme borreliosis was 0.8% (6/755) but was much higher (8.1%) for asymptomatic seroconversion (45/558). In conclusion, positive Lyme serology was common in Swiss orienteers, but clinical disease occurred infrequentl
Biological activities of 13, 28-epoxyoleanane triterpene saponins from two peruvian Myrsinaceae
Two known 13,28-epoxy-oleanane triterpene saponins (1) and (2), were isolated from the 95% ethanolic extract of the roots of Myrsine coriaceae and Myrsine andina. Their structures were deduced by combined spectral analysis and chemical evidences based on data reported in the literature. Compounds 1 and 2 were evaluated in vitro against different cellular models such as Mycobacterium tuberculosis, Leishmania amazonensis axenic amastigotes, six human cancer cell lines (Hs683, T98G, U251, HT29, MCF7, SKMEL28) and two murine cell lines (CT26 and B16F10). Compound 1 was found to exhibit antileishmanial activity (IC50 = 16 µg/mL) whereas compound 2 was inactive (IC50 > 50 µg/mL). Furthermore, compound 1 exhibited stronger inhibition activity on human cancer cells (IC50 = 15 µg/mL) and on murine cell lines (IC50 = 10 µg/mL) than compound 2 (IC50 > 82 and 42 µg/mL, respectively). As the only difference between 1 and 2 is due to a substitution of an aldehyde group by a hydroxymethyl moiety, these results showed the crucial role of the aldehyde function at C-30 for the cytotoxicity. In contrast, none of the tested compounds revealed activity against M. tuberculosis
Longitudinal study of Lyme borreliosis in a high risk population in Switzerland
Orienteers from all parts of Switzerland (n = 416) were included in a longitudinal study for Lyme borreliosis. In spring 1986, the seroprevalence was 28.1 %. At the beginning of the study, 84.3 % of orienteers reported a history of tick bite, and 3.8 % reported a past history of Lyme borreliosis. During the first (spring 1986-autumn 1986), second (autumn 1986-spring 1987) and third (spring 1987-autumn 1987) period, rates of seroconversion were 0.6 %, 2.7 % and 2.1 % respectively. During the first and second period, clinical incidence were 1.0 % and 0.25 % respectively. No active Lyme borreliosis was detected during the third period. Among orienteers who seroconverted during the study (n = 16), only two developed clinical symptoms. Hence, Borrelia burgdorferi infection is often asymptomatic
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