[Thin-layer chromatography of 6-aminopenicillanic acid and penicillins on talc].
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Chromatography, Thin Layer↗
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[Use of paper electrophoresis and thin layer chromatography on talc for erythromycin distribution].
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Chromatography, Thin Layer↗
Pleurodesis for malignant pleural effusions.
BACKGROUND: Approximately half of all patients with metastatic cancer develop a malignant pleural effusion which is likely to lead to a significant reduction in quality of life secondary to symptoms such as dyspnoea and cough. The aim of pleurodesis in these patients is to prevent re-accumulation of the effusion and thereby of symptoms, and avoid the need for repeated hospitalization for thoracocentesis. Numerous clinical studies have been performed to try to determine the optimal pleurodesis strategy, and synthesis of the available evidence should facilitate this. OBJECTIVES: The aims of this review were to ascertain the optimal technique of pleurodesis in cases of malignant pleural effusion; to confirm the need for a sclerosant; and to clarify which, if any, of the sclerosants is the most effective. SEARCH STRATEGY: The Cochrane Central Register of Controlled Trials was searched for studies on 'pleurodesis'. Studies for inclusion were also identified from MEDLINE (1980 to June 2002) and EMBASE (1980 to May 2002). No language restriction was applied. SELECTION CRITERIA: RCTs of adults subjects undergoing pleurodesis for pleural effusion in the context of metastatic malignancy (or a malignant process leading to pleural effusion) were included. DATA COLLECTION AND ANALYSIS: Two reviewers independently selected studies for inclusion in the review, and extracted data using a standard data collection form. Primary outcome measures sought were effectiveness of pleurodesis as defined by freedom from recurrence of effusions, and mortality after pleurodesis. Secondary outcomes were adverse events due to pleurodesis. Dichotomous data were meta-analysed using a fixed effect model and expressed as relative risk. The number-needed-to-treat (NNT) was calculated for pleurodesis efficacy. In addition, for adverse events, the overall percentage of patients across studies exhibiting a particular adverse effect such as fever, pain, or gastrointestinal symptoms was calculated. MAIN RESULTS: A total of 36 RCTs with 1499 subjects were eligible for meta-analysis. The use of sclerosants (mitozantrone, talc and tetracycline combined)compared with control (instillation of isotonic saline or equivalent pH isotonic saline or tube drainage alone) was associated with an increased efficacy of pleurodesis. The relative risk (RR) of non-recurrence of an effusion is 1.20 (95% CI 1.04 to 1.38) in favour of the use of sclerosants based on five studies with a total 228 subjects. Comparing different sclerosants, talc was found to be the most efficacious. The RR of effusion non-recurrence was 1.34 (95% CI 1.16 to 1.55) in favour of talc compared with bleomycin, tetracycline, mustine or tube drainage alone based on 10 studies comprising 308 subjects. This was not associated with increased mortality post pleurodesis. The RR of death was 1.19 (95% CI 0.08 to 1.77) for talc compared to bleomycin, tetracycline, mustine and tube drainage alone based on six studies of 186 subjects. Death was not reported in all studies and, when reported, was attributed to underlying disease, only one death being reported as procedure-related. In the comparison of thoracoscopic versus medical pleurodesis, thoracoscopic pleurodesis was found to be more effective. The RR of non-recurrence of effusion is 1.19 (95% CI 1.04 to 1.36) in favour of thoracoscopic pleurodesis compared with tube thoracostamy pleurodesis utilizing talc as sclerosant based on two studies with 112 subjects. Comparing thoracoscopic versus bedside instillation (with different sized chest tubes) of various sclerosants (tetracycline, bleomycin, talc or mustine) the RR of non-recurrence of effusion is 1.68 (95% CI 1.35 to 2.10) based on five studies with a total of 145 participants.Adverse events were not reported adequately to enable meta-analysis. REVIEWER'S CONCLUSIONS: The available evidence supports the need for chemical sclerosants for successful pleurodesis, the use of talc as the sclerosant of choice, and thoracoscopic pleurodesis as the preferred technique for pleurodesis based on efficacy. There was no evidence for an increase in mortality following talc pleurodesis.
Humans↗
Variation of composition of an enteric formulation based on Kollicoat MAE 30 D.
Using a formulation described previously with Kollicoat MAE 30 D as the film-forming agent, the effect of variations in plasticizer type and quantity and talc concentration on the preparation and processing of spray-coating suspensions and the properties of isolated films and film-coated caffeine tablets prepared using them was investigated. In the preparation and processing of spray-coating suspensions, the plasticizers polyethylene glycol (PEG) 400, PEG1500, and TEC (triethyl citrate) tended to coagulate at all concentrations investigated, while Cremophor RH 40 coagulated above 10% (expressed as a percentage of the mass of the film-forming agent used). Analogous preparations using propylene glycol (PG), PEG6000, and Lutrol F 68, on the other hand, were found to be stable at all concentrations. The instability was not caused by the Kollicoat MAE 30 D polymer dispersion as such, but by interactions between the finely dispersed pigments and other formulation ingredients. Equivalent nonpigmented preparations are stable and do not coagulate. With all the plasticizers investigated, the minimum film-forming temperature (MFT) fell, albeit to differing degrees, as the amount of plasticizer increased. Similarly, the tensile strength of isolated films declined as plasticizer concentration increased, while the reverse was true as regards their elongation at break. Whereas neither the subsequent disintegration time nor the rate of release of active ingredient at pH 6.8 was significantly affected by the various plasticizer additives, the different film-coated tablet formulations with a core containing a powerful disintegrant exhibited varying degrees of permeability to simulated gastric fluid. With PEG6000, permeability increased as the plasticizer concentration increased, while Lutrol F 68 provided an optimum barrier at 20%, and PG provided a good barrier between 10% and 30%. No gastroresistance was obtained with TEC at 10%. Only the best plasticizer formulations were used in the trials with different talc concentrations, namely, those formulations with 20% PEG6000, 20% Lutrol F 68, 20% PG, and 10% PG. When talc was added, the MFT rose, reaching its maximum at 13% talc (as a proportion of the film-forming agent). In the test for gastroresistance, film-coated caffeine tablets without talc absorbed distinctly more acid than those containing talc. Above 27% talc, the acid resistance improved only insignificantly. On the other hand, during this test, only a maximum of 3% of the active ingredient was released into the gastric juice. Of the variants investigated, the formulation with 20% PG and 27% talc performed best.
Administration, Oral↗
The evidence on the effectiveness of management for malignant pleural effusion: a systematic review.
The aim of this study was to review systematically the available evidence on pleurodesis for malignant effusion, focusing on the choice of the agents, route of delivery and other strategies to improve outcomes. Four electronic databases (MEDLINE, EMBASE, Web of Science and Cochrane Controlled Trials Register) were searched, reference lists checked and letters requesting details of unpublished trials and data sent to authors of previous trials. Studies of malignant pleural effusion in humans were selected with no language restrictions applied. Criteria for randomised clinical trial (RCT) eligibility were random allocation of patients and non-concurrent use of another experimental medication or device. Methodological quality evaluation of the trials was based on randomisation, blinding, allocation concealment and intention to treat analysis. A random effect model was used to combine the relative risk estimates of the treatment effects whenever pooling for an overall effect was considered appropriate. Forty-six RCTs with a total of 2053 patients with malignant pleural effusions were reviewed for effectiveness of pleurodesis. Talc tended to be associated with fewer recurrences when compared to bleomycin (RR, 0.64; 95% CI, 0.34-1.20) and, with more uncertainty, to tetracycline (RR, 0.50; 95% CI, 0.06-4.42). Tetracycline (or doxycycline) was not superior to bleomycin (RR, 0.92; 95% CI, 0.61-1.38). When compared with bedside talc slurry, thoracoscopic talc insufflation was associated with a reduction in recurrence (RR, 0.21; 95% CI, 0.05-0.93). Strategies such as rolling the patient after instillation of the sclerosing agent, protracted drainage of the effusion and use of larger chest tubes were not found to have any substantial advantages. Talc appears to be effective and should be the agent of choice for pleurodesis. Thoracoscopic talc insufflation is associated with fewer recurrences of effusions compared with bedside talc slurry, but this is based on two small studies. Where thoracoscopy is unavailable bedside talc pleurodesis has a high success rate and is the next best option.
Chest Tubes↗
Pleurodesis in recurrent pleural effusions: a randomized comparison of a classical and a currently popular drug.
STUDY OBJECTIVES: Pleurodesis is generally regarded to give the best palliation in recurrent pleural effusion. Talc is now increasingly recommended but in our department quinacrine has been used successfully for many decades with good results and only minor side effects. It was therefore decided to make a prospective randomized clinical study comparing quinacrine (500 mg) with talc (5 g) with regard to efficacy and safety. METHODS: One hundred and ten eligible consecutive patients with recurrent and or malignant effusions, from 1 March 1996 till 31 March 1999 were randomized to chemical pleurodesis with either talc or quinacrine through a chest drainage tube after medical thoracoscopy. Patients were evaluated with chest radiographs at 2 weeks and 2, 4, and 6 months after pleurodesis. RESULTS: Chi-square test showed 84% power to distinguish between the groups and 10% to determine the primary endpoint. Primary success (fluid production < 50ml/24h within the first 6 days) was 96% of 56 patients with talc and 91% of 54 patients with quinacrine, a non-significant difference (P = 0.46). Quinacrine patients needed a repeated treatment in 31% (17 patients) and talc patients in 7% (4 patients) (P < 0.05). Side effects were minor with no significant difference between the substances. CONCLUSIONS: Both substances are effective. Talc treatment had less often to be repeated. This indicates that the recommendation of talc for pleurodesis is well founded. However, quinacrine is a good alternative.
Antineoplastic Agents↗
Sepiolite asbestos from Franklin, New Jersey: a case study in medical geology.
Asbestiform sepiolite has been found in a zinc deposit at Franklin, New Jersey. The host rock is Precambrian Franklin marble. Pseudomorphous foliated texture and cross-cutting relationships indicate replacement of talc by sepiolite. Sepiolite is manganoan, while talc contains little manganese, suggesting differences in manganese substitution in these minerals and providing evidence against solid-state replacement. Sepiolite from Franklin is of moderate crystallinity and consists of soft, flexible mass-fiber. Comparison with other sepiolite samples suggests that increased crystallinity among sepiolites parallels increased fiber length, while disorder appears to be associated with flexibility. Length and aspect ratio (length/width) distributions support toxicological equation of asbestiform sepiolite with the regulated asbestos minerals. The data presented here suggest that talc can be unstable in a low-temperature hydrothermal environment, altering under certain conditions to form sepiolite. In a wider context, sepiolite may be expected to precipitate at the end-stages of hydrothermal mineralization in some talc deposits and in carbonate and calc-silicate rocks. Many occurrences of sepiolite in these rocks may have been overlooked due to similarities with other minerals. The fact that sepiolite has been previously unrecognized and misidentified at Franklin is a case in point. Since there is evidence suggesting that sepiolite is fibrogenic and carcinogenic, its potential occurrence in consumer talcs and crushed-stone products has environmental health implications. Similarities in composition and other analytical parameters may cause sepiolite to be mistaken for fibrous talc or chrysotile in environmental samples.
Geological Phenomena↗
Estrogen suppression of connective tissue deposition in a murine model of peritoneal adhesion formation.
Estrogen's involvement in inflammation and wound healing is poorly understood. To examine the role of estrogen in peritoneal adhesion formation, we gave ovariectomized female C57BL/6 mice time-release pellets containing placebo, 0.05 mg 17 beta-estradiol (low E2), or 5 mg 17 beta-estradiol (high E2) before i.p. injection of talc in saline or saline alone. Analyses of abdominal wall connective tissue thickness and peritoneal cell populations were performed. Talc-treated mice receiving low and high E2 replacement had a decreased amount of abdominal connective tissue deposition (29% and 65% decrease, respectively) as compared with talc-treated mice receiving placebo pellets. At high E2 replacement, the difference in connective tissue deposition was significant statistically (p less than 0.01). Immunohistochemical analysis revealed that the number of macrophages in adhesion tissue was proportionate to the amount of connective tissue present, regardless of the circulating levels of E2. Northern blot analysis of abdominal wall tissue showed that five of six talc-treated animals given placebo expressed mRNA for the murine monocyte chemoattractant protein-1 (MCP-1), JE. Conversely, only one of five talc-treated animals that received E2 replacement expressed JE/MCP-1 mRNA, suggesting that the hormone may inhibit connective tissue deposition by altering the production of chemotactic factors. Furthermore, E2 suppressed talc-induced expression of JE/MCP-1 mRNA in murine macrophages. Since macrophages play a central role in the wound healing process, these studies suggest that E2 inhibition of adhesion formation could be mediated by suppressing macrophage activation and/or recruitment to inflammatory sites.
Abdomen↗
Fibrin sealant inhibits connective tissue deposition in a murine model of peritoneal adhesion formation.
BACKGROUND: Postoperative peritoneal adhesion formation causes a multitude of disorders, including bowel obstruction and infertility. METHODS: To test whether fibrin sealant inhibits adhesion formation, mice were given an intraperitoneal injection of talc (to induce adhesions) after which sealant was administered. Seven and 14 days later, the thickness of connective tissue between the fragmented mesothelium and the abdominal muscle was measured. RESULTS: At both 7 and 14 days after talc administration, talc-treated mice had a 6-fold increase in connective tissue thickness over vehicle alone (P < .05). Although fibrin sealant alone failed to trigger peritoneal pathologic conditions, administration of sealant to talc-treated mice inhibited connective tissue deposition by 80% at 7 and 14 days (P < .05). Additionally, delaying fibrin sealant administration up to and including 72 hours after talc treatment results in comparable inhibition of connective tissue deposition, as does treatment immediately after talc exposure. CONCLUSIONS: This study demonstrates that fibrin sealant inhibits peritoneal inflammation and peritoneal adhesion formation with use of a quantitative assay of connective tissue deposition. In addition, this is the first report to document the administration of fibrin sealant into the closed abdomen. The success of these studies suggests that fibrin sealant will block peritoneal adhesions when administered laparoscopically. Finally, because fibrin sealant is therapeutic even when administered after the initiation of peritoneal inflammation, it suggests that it may be efficacious in patients who present with adhesions or those undergoing multiple operations.
Animals↗
What is the value of telerobotic technology in gastrointestinal surgery?
BACKGROUND: Although telerobotic technology has entered clinical application, its value for gastrointestinal surgery is unclear. Our objective was to evaluate the performance characteristics of telerobotically assisted laparoscopic cholecystectomy (TALC). METHODS: All TALCs performed using the da Vinci Surgical System between January 2000 and September 2001 at a tertiary academic medical center were analyzed. RESULTS: For this study, 20 patients (80% female) with a mean age of 47 +/- 4 years underwent TALC. All had symptomatic cholelithiasis, and all had successful TALC results without complications or need for conversion to conventional laparoscopic cholecystectomy (CLP). The mean procedure time was 152 +/- 8 min. The procedures were performed by one of three staff surgeons experienced in laparoscopic surgery who had training in telerobotic surgery. The perceived advantages of TALC over CLP included easier tissue dissection, enhanced dexterity, and stimulated interest in biliary surgery. The disadvantages included increased operating time and lack of tactile feedback. CONCLUSIONS: The TALC procedure is effective and safe when performed by appropriately trained surgeons. Telerobotic technology has the potential to reinvigorate gastrointestinal surgery.
Academic Medical Centers↗
Mechanisms of ethyl(hydroxyethyl) cellulose-solid interaction: influence of hydrophobic modification.
Hydroxyethyl cellulose and its hydrophobically modified derivatives are widely used in many industrial areas such as pharmaceuticals, cosmetics, textiles, paint and mineral industries. However, the interaction mechanisms of these biopolymers and solids have not been established. In this work, the interaction mechanism and conformation of hydrophobically modified ethyl(hydroxyethyl) cellulose (C(14)-EHEC) have been investigated using spectroscopic, AFM and allied techniques. Comparison was made with corresponding unmodified analogue in order to investigate the effects of the hydrophobic modification. Electrokinetic studies showed that polysaccharides adsorption decreased the negative zeta potential of talc but did not reverse the charge. EHEC adsorption on talc was not found to be affected significantly by changes in solution conditions such as pH and ionic strength, ruling out electrostatic force as the controlling factor. However, HM-EHEC adsorption was found to increase markedly with increase in ionic strength from 0.1 to 1 suggesting a role for the hydrophobic force in this adsorption process. Fluorescence spectroscopic studies conducted to investigate the role of hydrophobic bonding using pyrene probe showed no evidence of the formation of hydrophobic domains at talc-aqueous interface. Urea, a hydrogen bond breaker, reduced the adsorption of HM-EHEC on talc markedly. In FTIR study, the changes in the infrared bands, associated with the CO stretch coupled to the CC stretch and OH deformation, were significant and therefore support strong hydrogen bonding of HM-EHEC on the solid surface. Moreover, Langmuir modeling of the adsorption isotherms suggests hydrogen bonding to be a major force for the adsorption of EHEC and C(14)-EHEC on solid since the adsorption free energies of these polymers were close to that for hydrogen bond formation. All of the above results suggest that the main driving force for EHEC adsorption on talc is hydrogen bonding rather than electrostatic interaction or hydrophobic force. For hydrophobically modified C(14)-EHEC, hydrophobic force plays a synergetic role in adsorption along with hydrogen bonding. From computer modeling and AFM imaging, it is proposed that C(0)-EHEC and C(14)-EHEC adsorb flat on talc with ethylene oxide side chains and hydrophobic groups protruding out from the surface into bulk water phase.
Journal Article↗
Recurrent pleural effusion complicating liver cirrhosis.
BACKGROUND: Pleural effusion (PE) is a rare complication of advanced liver cirrhosis, which may lead to an operation when uncontrolled. The purpose of this study was to evaluate the modality of the occurrence of pleural effusion and to describe its surgical management. METHODS: We studied 21 patients who were referred to the department of thoracic surgery because of massive and recurrent PE caused by liver cirrhosis. The PE was a transudate in 16 patients and an exudate in 5. Talc pleurodesis was attempted in all patients. The patients were divided into two groups. Video assisted thoracoscopy was performed in 13 patients in whom the clinical condition permitted general anesthesia; the pleural cavity was entirely explored before pleurodesis (group 1). Chest tube drainage alone was performed in 8 patients who were unable to undergo general anesthesia; talc pleurodesis was performed through the chest tube in these patients (group 2). RESULTS: In group 1 the PE was right-sided in 8 patients, left-sided in 3, and bilateral in 2. Diaphragmatic defects were observed in 2 patients, and a fluid leak oozing from the diaphragm was observed in 1 patient. Ten patients were considered cured and were without recurrence. Two patients underwent late recurrence before dying from their liver cirrhosis. Only 1 patient had an early recurrence that was cured by complementary talc slurry. In group 2 all patients presented with a right PE; of these, 3 patients died from septic shock caused by pleural infection. Three patients underwent early recurrence but were cured after repeat talc slurry. One patient had a midterm recurrence. One patient had an early recurrence treated by intrahepatic porto-systemic shunt with partial improvement. CONCLUSIONS: Passage of ascites through diaphragmatic defects appears to be the main cause of PE complicating cirrhosis. Patients may benefit from talc pleurodesis. Video assisted thoracoscopy pleurodesis is the technique of choice with consistent results. Repeated talc injection through the drain may prove useful for patients in poor clinical status.
Adult↗
Recurrences following videothoracoscopic treatment of primary spontaneous pneumothorax: the role of redo-videothoracoscopy.
OBJECTIVE: There is very little experience regarding recurrences following videothoracoscopic (VATS) treatment of primary spontaneous pneumothorax. We report our experience with 19 patients who underwent redo-VATS to evaluate the feasibility of such surgical approach. METHODS: From July 1, 1992 to September 1, 2000, out of 2136 VATS procedures performed at our institution, 597 patients (27.94%) underwent VATS treatment of primary spontaneous pneumothorax with a recurrence rate of 3.85% (23 cases). Primary VATS treatment in these patients was: talc poudrage, three cases; subtotal pleurectomy, three cases; ligation of the bullae + subtotal pleurectomy, 12 cases; stapling of the bullae + subtotal pleurectomy, two cases; ligation of the bullae + talc poudrage, one case; stapling of the bullae + talc poudrage, one case. Treatment of the 23 recurrences included: 15 redo-VATS, four standard thoracotomy, three pleural drainage, one bed rest. Four additional redo-VATS were also performed in four patients operated on in different institutions. Redo-VATS showed residual bullae in nine cases and a minimal leaking area in one patient; in the remaining nine patients no lesion was found. Redo-VATS treatment was: stapling of the bullae + talc poudrage in nine patients; suture of the leaking area with a no-knife stapler + talc poudrage in one patient; isolated talc poudrage in the remaining nine patients with no-evidence of bullae or blebs. RESULTS: No mortality was reported; no major complications occurred. The conversion rate in the group of redo-VATS was 5.2% (one patient). At a mean follow-up of 32 months no patient showed recurrent pneumothorax. CONCLUSIONS: In the light of our initial experience, redo-VATS seems to be a promising tool for the surgical therapy of recurrences following VATS treatment of primary spontaneous pneumothorax.
Drainage↗
Structure and decompression melting of a novel, high-pressure nanoconfined 2-D ice.
Molecular dynamics (MD) simulations of water confined in nanospaces between layers of talc (system composition Mg(3)Si(4)O(10)(OH)(2) + 2H(2)O) at 300 K and pressures of approximately 0.45 GPa show the presence of a novel 2-D ice structure, and the simulation results at lower pressures provide insight into the mechanisms of its decompression melting. Talc is hydrophobic at ambient pressure and temperature, but weak hydrogen bonding between the talc surface and the water molecules plays an important role in stabilizing the hydrated structure at high pressure. The simulation results suggest that experimentally accessible elevated pressures may cause formation of a wide range of previously unknown water structures in nanoconfinement. In the talc 2-D ice, each water molecule is coordinated by six O(b) atoms of one basal siloxane sheet and three water molecules. The water molecules are arranged in a buckled hexagonal array in the a-b crystallographic plane with two sublayers along [001]. Each H(2)O molecule has four H-bonds, accepting one from the talc OH group and one from another water molecule and donating one to an O(b) and one to another water molecule. In plan view, the molecules are arranged in six-member rings reflecting the substrate talc structure. Decompression melting occurs by migration of water molecules to interstitial sites in the centers of six-member rings and eventual formation of separate empty and water-filled regions.
Journal Article↗
The effects of intrapleural polyclonal anti-tumor necrosis factor alpha (TNF alpha) Fab fragments on pleurodesis in rabbits.
The mechanism by which various agents produce a pleurodesis is unknown. The purpose of this project was to determine whether the pleurodesis that results from the intrapleural administration of talc or doxycycline depends on tumor necrosis factor alpha (TNF alpha). In a randomized, blinded, placebo-controlled study, 34 New Zealand white rabbits were given 400 mg talc or 10 mg/kg doxycycline intrapleurally as a sclerosant through a chest tube. Half the rabbits in each group were also given 2,000 units of ovine, polyclonal affinity purified anti-TNF alpha Fab, or saline as placebo immediately after and 12 h after the injection of the sclerosant. Chest tubes were aspirated at 12-h intervals until their removal at 4 days. Rabbits were killed at 28 days. The pleural fluid volume, cell counts, lactate dehydrogenase (LDH) and pleurodesis scores were compared among groups. Both talc and doxycycline produced an exudative pleural effusion. The pleural fluid volume and the pleural fluid LDH levels were significantly (p < 0.05) greater in the group given doxycycline. The administration of anti-TNF alpha Fab had no significant effect on pleural fluid volume or leukocyte count in either group. However, the administration of anti-TNF alpha Fab resulted in a significant decrease (p = 0.004) in the pleurodesis score for the animals given talc (3.2 +/- 0.8 without Fab and 1.8 +/- 0.9 with Fab). In contrast, the pleurodesis score was virtually identical in the doxycycline group with (3.5 +/- 0.5) and without (3.4 +/- 0.7) Fab. The administration of anti-TNF alpha Fab diminishes the pleurodesis induced by talc but not that resulting from doxycycline. These findings suggest that different mechanisms are involved with the two different sclerosants.
Animals↗
Management of recurrent malignant pleural effusion with chemical pleurodesis.
PURPOSE: Malignant pleural effusion is a common complication of primary and metastatic pleural malignancies. It is usually managed by drainage and pleurodesis, but there is no consensus as to the best method of pleurodesis. We compared the effectiveness, side effects, and cost of different chemical pleurodesis agents used in patients with malignant pleural effusion. METHODS: Between January 1990 and December 2001, 108 patients with malignant pleural effusion underwent chemical pleurodesis in our department. Thoracoscopy was performed in 64 patients (59%), a minithoracotomy in 18 (17%), tube thoracostomy in 11 (10%), and a small-bore catheter was inserted in 15 (14%). Talc was used in 68 (63%) patients, tetracycline in 26 (24%), and bleomycin in 14 (13%). Talc was instilled by insufflation during surgery after drainage, whereas tetracycline and bleomycin were instilled via tube or catheter for pleural analgesia. RESULTS: Talc resulted in significantly earlier tube and catheter removal, after an average 4.1 days versus 5.1 days after tetracyline, and 6.3 days after bleomycin (P = 0.026, P = 0.001, respectively). A significantly lower reaccumulation ratio in 90 days was achieved by the talc group, with nine (13.2%) patients, representing an 86.8% success rate, than in the tetracyline and bleomycin groups, with seven (26.7%) and five (35.7%) patients, respectively, representing 73.8% and 64.3% success rates (P = 0.04). CONCLUSIONS: Talc resulted in the earliest expansion, minimal drainage, and the earliest tube and catheter removal.
Adult↗
Adsorption and conformation of carboxymethyl cellulose at solid-liquid interfaces using spectroscopic, AFM and allied techniques.
Carboxymethyl cellulose (CMC) is a polysaccharide which is widely used in many industrial sectors including food, textiles, paper, adhesives, paints, pharmaceutics, cosmetics and mineral processing. It is a natural organic polymer that is non-toxic and biodegradable. These properties make it ideal for industrial applications. However, a general lack of understanding of the interaction mechanism between the polysaccharides and solid surfaces has hindered the application of this polymer. In this work, adsorption of CMC at the solid-liquid interface is investigated using adsorption and electrophoretic mobility measurements, FTIR, fluorescence spectroscopy, AFM and molecular modeling. CMC adsorption on talc was found to be affected significantly by changes in solution conditions such as pH and ionic strength, which indicates the important role of electrostatic force in adsorption. The pH effect on adsorption was further proven by AFM imaging. Electrokinetic studies showed that the adsorption of CMC on talc changed its isoelectric point. Further, molecular modeling suggests a helical structure of CMC in solution while it is found to adsorb flat on the solid surface to allow its OH groups to be in contact with the surface. Fluorescence spectroscopy studies conducted to investigate the role of hydrophobic bonding using pyrene probe showed no evidence of the formation of hydrophobic domains at talc-aqueous interface. Urea, a hydrogen bond breaker, markedly reduced the adsorption of CMC on talc, supports hydrogen bonding as an important factor. In FTIR study, the changes to the infrared bands, associated with the CO stretch coupled to the CC stretch and OH deformation, were significant and this further supports the strong hydrogen bonding of CMC to the solid surface. In addition, Langmuir modeling of the adsorption isotherm suggests hydrogen bonding to be a dominant force for polysaccharide adsorption since the adsorption free energy of this polymer was close to that for hydrogen bond formation. All of the above results suggest that the main driving forces for CMC adsorption on talc are a combination of electrostatic interaction and hydrogen bonding rather than hydrophobic force.
Adsorption↗
Consumer talcums and powders: mineral and chemical characterization.
Representative consumer talcums and powders, including 20 body powders, baby powders, facial talcums, and also one pharmaceutical talc, were analyzed to determine their mineralogical and chemical composition. Where known, all were formulated prior to 1973. Of the 20 products 10 contained detectable amounts of tremolite and anthophyllite, principally asbestiform, while some also contained fragmented forms of these minerals. The amounts ranged from tenths of a percent to over 14% by weight; two contained detectable amounts of chrysotile asbestos fiber. Eight contained quartz, seven ranging from 2 to 5%, with one as high as 35%. The analyses showed that the consumer products examined were rarely the pure mineral talc, but rather were mixtures of various minerals; some samples consisted of three to five minerals, only one of which was talc. Other common mineral phases included chlorite, platy serpentine, pyrophyllitem mica, and carbonate minerals. Kaolin additive was identified in two products. The single pharmaceutical talc examined contained only a trace amount of quartz. The chemical composition of these products, including both major oxide and trace element content, correlated with their mineral components. Four samples contained substantial concentrations of nickel, cobalt, and chromium, suggesting latice substitution or the presence of trace mineral phases. Geological provenance of the talcs may be ascertained on the basis of chemistry. Possible adverse health effects from intermittent use of these products, especially those that contain asbestiform and fragmented anthophyllite and tremolite, chrysotile, quartz, and trace metals, are presently unknown and warrnat evaluation.
Asbestos↗