Effectiveness of silver nitrate compared to talc slurry as pleural sclerosing agent in rabbits. Influence of concomitant intrapleural lidocaine

The ideal agent for producing pleurodesis has not been identified. Talc, the most commonly used, poses several problems. Another possibility is silver nitrate, which was widely used in the past. PURPOSE: To determine the influence of the intrapleural instillation of lidocaine in producing a pleurodesis with silver nitrate, to define the effect of lidocaine in the maturation of the collagen fibers, and to confirm that the pleurodesis after silver nitrate is stronger than after talc. METHODS: We studied three groups of 8 rabbits. Two groups received 0.5% silver nitrate; in one we had previously injected 0.5 ml of 2% lidocaine. The third group received 400 mg/kg talc (2 ml). The animals were sacrificed 28 days after the injection, and the pleural spaces were assessed grossly for evidence of pleurodesis and microscopically for evidence of inflammation and fibrosis. The total amount of pleural collagen and the distribution of thick and thin collagen fibers were quantified. Collagen was identified using picrosirius red stain. RESULTS: In the two groups that received silver nitrate (without lidocaine: 3.5 + 03 and with lidocaine: 3.2 + 0.3), the macroscopic pleurodesis (scale 0 -- 4) was significantly (p = 0.001) better than that resulting from talc (1.6 + 0.2). The mean degree of pleural fibrosis induced by silver nitrate (3.5 + 0.2) was significantly (p = 0.004) higher than that induced by talc (1.9 + 0.1). The previous instillation of lidocaine resulted in a tendency for decreased amounts of fibrosis (3.1 + 0.4). The mean amount (10³mm²) of pleural collagen was significantly (p = 0.009) greater in the rabbits that received silver nitrate (116.9 + 22.7) than in those that received talc (10.7 + 3.4). The injection of lidocaine slightly reduced the collagen (80.1 + 30.3). The distribution of collagen fibers did not differ among the groups. CONCLUSION: This rabbit model clearly confirms that intrapleural silver nitrate is more effective than talc for producing pleurodesis. The previous intrapleural instillation of lidocaine results in a decreasing trend in the amount of collagen, but does not change the effectiveness of the pleural fusion or modify the process of collagen maturation.

Monoclonal anti-vascular endothelial growth factor antibody reduces fluid volume in an experimental model of inflammatory pleural effusion

Background and objective: Vascular endothelial growth factor (VEGF) is known to increase vascular permeability and promote angiogenesis. It is expressed in most types of pleural effusions. However, the exact role of VEGF in the development of pleural effusions has yet to be determined. The anti-VEGF mAb, bevacizumab, has been used in the treatment of cancer to reduce local angiogenesis and tumour progression. This study describes the acute effects of VEGF blockade on the expression of inflammatory cytokines and pleural fluid accumulation. Methods: One hundred and twelve New Zealand rabbits received intrapleural injections of either talc or silver nitrate. In each group, half the animals received an intravenous injection of bevacizumab, 30 min before the intrapleural agent was administered. Five animals from each subgroup were sacrificed 1, 2, 3, 4 or 7 days after the procedure. Twelve rabbits were used to evaluate vascular permeability using Evans`s blue dye. Pleural fluid volume and cytokines were quantified. Results: Animals pretreated with anti-VEGF antibody showed significant reductions in pleural fluid volumes after talc or silver nitrate injection. IL-8 levels, vascular permeability and macroscopic pleural adhesion scores were also reduced in the groups that received bevacizumab. Conclusions: This study showed that bevacizumab interferes in the acute phase of pleural inflammation induced by silver nitrate or talc, reinforcing the role of VEGF as a key mediator in the production of pleural effusions. The results also suggest that bevacizumab should probably be avoided in patients requiring pleurodesis.

Is Silver Nitrate Pleurodesis for Patients with Malignant Pleural Effusion Feasible and Safe When Performed in an Outpatient Setting?

The purpose of this study was to analyze the effectiveness and safety of silver nitrate pleurodesis (SNP) in patients with recurrent malignant pleural effusion (RMPE) when performed in an outpatient setting. Prospective study including patients with RMPE recruited in a tertiary university-based hospital from February 2008 to June 2009. Elected patients underwent pleural catheter insertion (Day 1) followed by 0.5% SNP (Day 2), and on 7th day the drain was removed. All procedures were performed in an outpatient facility. Pleurodesis was considered successful when no additional pleural procedure was necessary by the 30th day. Complications were registered and graded according to the CTCAE3.0. Quality of life was evaluated before and 30 days after SNP. A total of 68 patients (54 female, 14 male, mean age: 57.3 years) were included. In addition, 7 had bilateral pleural effusions; therefore, 75 hemithoraces were drained. Also, 5 were excluded, and 70 hemithoraces (63 patients) underwent SNP. During the period of 30 days postpleurodesis, 8 deaths not related to the procedure occurred, and we lost contact with 10 patients who were followed elsewhere. At the 30th day, 48 hemithoraces (45 patients) were reevaluated, and 2 recurrences observed. The most frequent complication was pain-graded as 3 or more in 7 patients; infection occurred in 2 patients. Physical and environmental aspects of quality of life improved significantly after pleurodesis. In this study, SNP could be performed safely in an outpatient setting, with pain the most frequent complication. Recurrences occurred in 4% of the patients.

Acute inflammatory response secondary to intrapleural administration of two types of talc

Intrapleural instillation of talc has been used in the treatment of recurrent pleural effusions but can, in rare instances, result in respiratory failure. Side-effects seem to be related to composition, size and inflammatory power of talc particles. The aim of this study was to evaluate the inflammatory response to intrapleural injection of talc containing small particles (ST) or talc containing particles of mixed size (MT). 100 rabbits received intrapleural talc, 50 with ST (median 6.41 mu m) and 50 with MT median 21.15 mu m); the control group was composed of 35 rabbits. Cells, lactate dehydrogenase, C-reactive protein (CRIP), interleukin (IL)-8 and vascular endothelial growth factor were evaluated in serum and bronchoalveolar lavage at 6, 24, 48, 72 and 96 h. Lung histology and the presence of talc were also analysed. Statistics were performed using ANOVA and an unpaired t-test. Most of the parameters showed greater levels in the animals injected with talc than in the controls, suggesting a systemic and pulmonary response. Higher serum levels of CRP and IL-8 were observed in the animals injected with ST. Talc particles were observed in both lungs with no differences between groups. Lung cell infiltrate was more evident in the ST group. In conclusion, talc with larger particles should be the preferred choice in clinical practice in order to induce safer pleurodesis.

Talc pleurodesis: Evidence of systemic Inflammatory response to small size talc particles

The mechanisms of the systemic response associated with talc-induced pleurodesis are poorly understood. The aim of this study was to assess the acute inflammatory response and migration of talc of small. size particles injected in the pleural space. Rabbits were injected intrapleurally with talc solution containing small. or mixed particles and blood and pleural fluid samples were collected after 6, 24 or 48 h and assayed for leukocytes, neutrophils, lactate dehydrogenase, IL-8, VEGF, and TGF-beta. The lungs, spleen, liver and kidneys were assessed to study deposit of talc particles. Both types of talc produced an acute serum inflammatory response, more pronounced in the small particles group. Pleural fluid IL-8 and VEGF levels were higher in the small particle talc group. Correlation between pleural VEFG and TGF-beta levels was observed for both groups. Although talc particles were demonstrated in the organs of both groups, they were more pronounced in the small talc group. In conclusion, intrapleural injection of talc of small size particles produced a more pronounced acute systemic response and a greater deposition in organs than talc of mixed particles. (C) 2008 Elsevier Ltd. All rights reserved.

Is Full Postpleurodesis Lung Expansion a Determinant of a Successful Outcome After Talc Pleurodesis?

Study objectives: To analyze and compare radiologic lung expansion after tale pleurodesis performed either by videothoracoscopy or chest tube and correlate it with clinical outcome. Secondary end points evaluated were its follows: clinical efficacy; quality of life; safety; and survival. Methods: Prospective randomized study that included 60 patients (45 women, 15 men; mean age, 55.2 years) with recurrent malignant pleural effusion between January, 2005 and January 2008. They were randomized into the following two groups: video-assisted thoracic surgery (VATS) talc poudrage; and tale slurry (TS) administered through a chest tube. Lung expansion was evaluated through chest CT scans obtained 0, 1, 3 and 6 months after pleurodesis. Complications, drainage time, hospital stay,and quality of life (Medical Outcomes Study 36-item short form and World Health Organization quality-of-life questionnaires) were also analyzed. Results: There were no significant differences in preprocedure clinical and pathologic variables between groups. The immediate total (ie, > 90%) lung expansion was observed in 27 patients (45%) and wits more frequent in the VATS group (60% vs 30%, respectively; p = 0.027). During follow-up, 71% of the patients showed unaltered or improved lung expansion and 9 patients (15%) needed new pleural procedures (VATS group, 5 recurrences; TS group, 4 recurrences; p = 0.999). No differences, were found between groups regarding quality of life, complications, drainage time, hospital stay, and survival. Immediate lung expansion (lid not correlate with radiologic recurrence, clinical recurrence, or complications (p = 0.60, 0.15, and 0.20, respectively). Conclusion: Immediate partial lung expansion was a frequent finding and was more frequent after TS. Nonetheless, no correlation between immediate lung expansion and clinical outcome was found in this study. (CHEST 2009; 136:361-368)

Degradation of phenanthrene and pyrene in soil slurry reactors with immobilized bacteria Zoogloea sp.

The environmental fate of polycyclic aromatic hydrocarbons (PAHs) in soils is motivated by their wide distribution, high persistence, and potentially deleterious effect on human health. Polycyclic aromatic hydrocarbons constitute the largest group of environmental contaminants released in the environment. Therefore, the potential biodegradation of these compounds is of vital importance. A biocarrier suitable for the colonization by micro-organisms for the purpose of purifying soil contaminated by polycyclic aromatic hydrocarbons was developed. The optimized composition of the biocarrier was polyvinyl alcohol (PVA) 10%, sodium alginate (SA) 0.5%, and powdered activated carbon (PAC) 5%. There was no observable cytotoxicity of biocarriers on immobilized cells and a viable cell population of 1.86 x 10(10) g(-1) was maintained for immobilized bacterium. Biocarriers made from chemical methods had a higher biodegradation but lower mechanical strengths. Immobilized bacterium Zoogloea sp. had an ideal capability of biodegradation for phenanthrene and pyrene over a relative wide concentration range. The study results showed that the biodegradation of phenanthrene and pyrene reached 87.0 and 75.4%, respectively, by using the optimal immobilized method of Zoogloea sp. cultivated in a sterilized soil. Immobilized Zoogloea sp. was found to be effective for biodegrading the soil contaminated with phenanthrene and pyrene. Even in natural (unsterilized) soil, the biodegradation of phenanthrene and pyrene using immobilized Zoogloea sp. reached 85.0 and 67.1%, respectively, after 168 h of cultivation, more than twice that achieved if the cells were not immobilized on the biocarrier. Therefore, the immobilization technology enhanced the competitive ability of introduced micro-organisms and represents an effective method for the biotreatment of soil contaminated with phenanthrene and pyrene.

Low doses of silver nitrate induce pleurodesis with a limited systemic response

Background and objective: Both talc and 0.5% silver nitrate have been shown to induce effective pleurodesis. However, acute adverse systemic inflammatory effects have been described with both agents. The aim of this study was to assess in rabbits the systemic effects associated with a new technique of pleurodesis using repeated low doses of 0.1% silver nitrate. Methods: Rabbits were injected intrapleurally through a chest tube with 0.1% silver nitrate at 0, 24 and 48 h. Other groups received a single injection of 0.5% silver nitrate or 400 mg/kg of talc. Blood samples were collected at 24, 48 and 72 h, and at 7 days, and cytological and biochemical measurements were performed. After 28 days, the presence of macroscopic pleural adhesions and microscopic pleural fibrosis in the pleural cavity were evaluated. Results: Both talc and 0.5% silver nitrate caused significant increases in blood neutrophils, serum LDH, IL-8, transforming growth factor-beta and CRP in comparison with control at almost all time points, whereas sequential doses of 0.1% silver nitrate only increased LDH and CRP in the first 24 h and transforming growth factor-beta at all time points. All groups showed efficient pleurodesis, with no differences in pleural adhesions or fibrosis. Conclusions: Sequential doses of 0.1% silver nitrate produced efficient pleurodesis in rabbits, with a low systemic inflammatory response in comparison with 400 mg/kg of talc or 0.5% silver nitrate.

Effects of slurry rheology on industrial grinding performance

To determine the effect of slurry rheology on industrial grinding performance, 45 surveys were conducted on 16 full-scale grinding mills in five sites. Four operating variables - mill throughput, slurry density, slurry viscosity and feed fines content-were investigated. The rheology of the mill discharge slurries was measured either on-line or off-line, and the data were processed using a standard procedure to obtain a full range of flow curves. Multi-linear regression was employed as a statistical analysis tool to determine whether or not rheological effects exert an influence on industrial grinding, and to assess the influence of the four mill operating conditions on mill performance in terms of the Grinding Index, a criterion describing the overall breakage of particles across the mill. The results show that slurry rheology does influence industrial grinding. The trends of these effects on Grinding Index depend upon the rheological nature of the slurry-whether the slurries are dilatant or pseudoplastic, and whether they exhibit a high or low yield stress. The interpretation of the regression results is discussed, the observed effects are summarised, and the potential for incorporating rheological principles into process control is considered, Guidelines are established to improve industrial grinding operations based on knowledge of the rheological effects. This study confirms some trends in the effect of slurry rheology on grinding reported in the literature, and extends these to a broader understanding of the relationship between slurry properties and rheology, and their effects on industrial milling performance. (C) 2002 Elsevier Science B.V. All rights reserved.

Investigation of the effects of chrome ball charge on slurry rheology and milling performance

Ten surveys of the ball milling circuit at the Mt Isa Mines (MIM) Copper Concentrator were conducted aiming to identify any changes in slurry theology caused by the use of chrome balls charge, and the associated effect on grinding performance. Slurry theology was measured using an on-line viscometer. The data were mass balanced and analysed with statistical tools. Comparison of the rheogram demonstrated that slurry density and fines content affected slurry rheology significantly, while the effect of the chrome ball charge being negligible. Statistical analysis showed the effects of mill throughput and cyclone efficiency on the Grinding Index (a term describing the overall breakage). There was no difference in the Grinding Index between using the chrome ball charge and the ordinary steel ball charge. (C) 2002 Elsevier Science Ltd. All rights reserved.

Slurry flow in mills: grate-pulp lifter discharge systems (Part 2)

Pulp lifters, also known, as pan lifters are an integral part of the majority of autogenous (AG), semi-autogenous (SAG) and grate discharge ball mills. The performance of the pulp lifters in conjunction with grate design determines the ultimate flow capacity of these mills. Although the function of the pulp lifters is simply to transport the slurry passed through the discharge grate into the discharge trunnion, their performance depends on their design as well as that of the grate and operating conditions such as mill speed and charge level. However, little or no work has been reported on the performance of grate-pulp lifter assemblies and in particular the influence of pulp lifter design on slurry transport. Ideally, the discharge rate through a grate-pulp lifter assembly should be equal to the discharge rate through at a given mill hold-up. However, the results obtained have shown that conventional pulp lifter designs cause considerable restrictions to flow resulting in reduced flow capacity. In this second of a two-part series of papers the performance of conventional pulp lifters (radial and spiral designs) is described and is based on extensive test work carried out in a I m diameter pilot SAG mill. (C) 2003 Elsevier Science Ltd. All rights reserved.

Slurry flow in mills: grate-only discharge mechanism (Part-1)

Discharge grates play an important role in determining the performance of autogenous, semi-autogenous and grate discharge ball mills. The flow capacity (grinding capacity) of these mills is strongly influenced by the discharge grate design-open area and position of apertures, as well as the performance of the pulp lifters. As mill sizes have progressively increased and closed-circuiting has become more popular the importance of grate and pulp lifter design has grown. Unfortunately very few studies have concentrated on this aspect of mill performance. To remedy this a series of laboratory and pilot-scale tests were undertaken to study both the performance of grates on their own and in conjunction with pulp lifters. In this first paper of a two-part series the results from the grate-only experiments are presented and discussed, whilst the performance of the grate-pulp-lifter system is covered in the second paper. The results from the grate-only experiments have shown that the build-up of slurry (hold-up) inside the mill starts from the shoulder of the charge, while the toe position of the slurry progressively moves towards the toe of the charge with increasing flowrate. Besides grate design (open area and position of apertures), charge volume and mill speed were also found to have a strong influence on mill hold-up and interact with grate design variables. (C) 2003 Elsevier Science Ltd. All rights reserved.

Thermomechanical environment characterisation in injection moulding and its relation to the mechanical properties of talc-filled polypropylene

This study is focused on the establishment of relationships between the injection moulding processing conditions, the applied thermomechanical environment (TME) and the tensile properties of talc-filled polypropylene,adopting a new extended concept of thermomechanical indices (TMI). In this approach, TMI are calculated from computational simulations of the moulding process that characterise the TME during processing, which are then related to the mechanical properties of the mouldings. In this study, this concept is extended to both the filling and the packing phases, with new TMI defined related to the morphology developed during these phases. A design of experiments approach based on Taguchi orthogonal arrays was adopted to vary the injection moulding parameters (injection flow rate, injection temperature, mould wall temperature and holding pressure), and thus, the TME. Results from analysis of variance for injection-moulded tensile specimens have shown that among the considered processing conditions, the flow rate is the most significant parameter for the Young’s modulus; the flow rate and melt temperature are the most significant for the strain at break; and the holding pressure and flow rate are the most significant for the stress at yield. The yield stress and Young’s modulus were found to be governed mostly by the thermostress index (TSI, related to the orientation of the skin layer), whilst the strain at break depends on both the TSI and the cooling index (CI, associated to the crystallinity degree of the core region). The proposed TMI approach provides predictive capabilities of the mechanical response of injection-moulded components, which is a valuable input during their design stage.

The influence of use additives on nitrous oxide emission during swine slurry composting.

use of additives (Mg/P and nitrification inhibitor dicyandiamide - DCD), on nitrous oxide emission during swine slurry composting. The experiment was run in duplicate; the gas was monitored for 30 days in different treatments (control, DCD, Mg/P and DCD + Mg/P). Nitrous oxide emissions rate (mg of N2O-N.day-1) and the accumulated emissions were calculated to compare the treatments. Results has shown that emissions of N-N2O were reduced by approximately 70, 46 and 96% through the additions of DCD, MgCl2.6H2O + H3PO4 and both additives, respectively, compared to the control. Keywords Composting; swine slurry; additives; nitrous