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At least 919 records · Page 51Linked to original sources
PubMed1997

Tubal sterilisation, hysterectomy and decreased risk of ovarian cancer. Survey of Women's Health Study Group.

We have examined the effect of tubal sterilisation and hysterectomy on risk of ovarian cancer in a large case-control study in eastern Australia involving 824 women aged 18-79 years, diagnosed with epithelial ovarian cancer between 1990 and 1993, and 855 controls randomly selected from the electoral roll. Relative risks for ovarian cancer were estimated using multiple categorical regression to adjust for age, parity, oral contraceptive use and other risk factors. Tubal sterilisation was associated with a 39% reduction in risk of ovarian cancer (RR 0.61, 95% CI 0.46-0.85) and hysterectomy with a 36% reduction (RR 0.64, 95% CI 0.48-0.85). Risk remained low 25 years after surgery and was reduced irrespective of sterilisation technique, and estimates were similar among various types of epithelial ovarian cancer. The greatest reduction (74%) was observed among women with primary peritoneal tumours. Pelvic infection and use of vaginal sprays or contraceptive foams were not related to ovarian cancer, while use of talc in the perineal region slightly but significantly increased risk among women with patent fallopian tubes. Reportedly heavy or painful menses, perhaps associated with retrograde flow, were associated with ovarian cancer, and reduction in risk of disease after hysterectomy was greatest among women who had heavy periods. Our findings support the theory that contaminants from the vagina, such as talc, and from the uterus, such as endometrium, gain access to the peritoneal cavity through patent fallopian tubes and may enhance the malignant transformation of ovarian surface epithelium. Surgical tubal occlusion may reduce the risk of ovarian cancer by preventing the access of such agents.

Adolescent↗
PubMed1994

Asbestos-related disease associated with exposure to asbestiform tremolite.

Tremolite is nearly ubiquitous and represents the most common amphibole fiber in the lungs of urbanites. Tremolite asbestos is not mined or used commercially but is a frequent contaminant of chrysotile asbestos, vermiculite, and talc. Therefore, individuals exposed to these materials or to end-products containing these materials may be exposed to tremolite. We have had the opportunity to do asbestos body counts and mineral fiber analysis on pulmonary tissue from five mesothelioma cases and two asbestosis cases with pulmonary tremolite burdens greater than background levels. There were no uncoated amosite or crocidolite fibers detected in any of these cases. Three patients were occupationally exposed to chrysotile asbestos; two patients had environmental exposures (one to vermiculite and one to chrysotile and talc) and one was a household contact of a shipyard worker. The tremolite burdens for the asbestosis cases were one to two orders of magnitude greater than those for the mesothelioma cases. Our study confirms the relationship between tremolite exposure and the development of asbestos-associated diseases. Furthermore, the finding of relatively modest elevations of tremolite content in some of our mesothelioma cases suggests that, at least for some susceptible individuals, moderate exposures to tremolite-contaminated dust can produce malignant pleural mesothelioma.

Adult↗
PubMed2006

Investigation of solid-state NMR line widths of ibuprofen in drug formulations.

Solid-state nuclear magnetic resonance spectroscopy (SSNMR) line widths were measured for various ibuprofen preparations, including crystallization from different solvents (acetone, acetonitrile, methanol), melt-quenching, manual grinding, cryogrinding, compacting, and by blending with various excipients. Ibuprofen recrystallized from acetonitrile exhibited broader lines than ibuprofen recrystallized from either acetone or methanol. Manually ground ibuprofen had SSNMR line widths that were indistinguishable from the commercial sample, but cryoground ibuprofen had larger line widths than either. Physical mixtures with most excipients decreased the SSNMR line widths. Only dilution in talc led to line width increases, which is attributed to the magnetic susceptibility anisotropy of the talc excipient. Our results show that SSNMR line widths can be used to understand physical characteristics including particle size and morphology, degree of order in the materials, and physical environment.

Chemistry, Pharmaceutical↗
PubMed1994

Free radical generation during interaction of chrysotile asbestos with natural compounds.

Free radical generation was found after the addition of some natural biological substances (adrenaline, ascorbate, ubiquinone Q9, etc.) to a chrysotile asbestos suspension. This was detected by the chemiluminescent method with lucigenin as an indicator. The detailed study of the chemiluminescent reaction in the adrenaline-chrysotile system indicated that the reaction required hydroxyl ions, which arose in the chrysotile suspension, and was accompanied by a superoxide radical formation. At the same time, the radical production was very low in suspensions of amphybole asbestos, talc, and quartz, which could not alkalinize the water medium. On the basis of these results, it may be concluded that chrysotile has a unique ability to generate free radicals upon interaction with some biological molecules in a water medium. This fact may explain the great carcinogenicity of chrysotile. The injection of cigarette smoke solution into chrysotile (but not into amphibole asbestos or talc) suspension induced intensive chemiluminescence. This suggests that smoke aggravates the effect of chrysotile on human health by increasing free radical generation on the surface of the fibers.

Asbestos, Amphibole↗
PubMed1990

The role of thoracoscopy in the evaluation and management of pleural effusions.

Diagnostic thoracoscopy is indicated in every patient where the usual investigations (including biochemistry, cytology, bacteriology, occasionally needle biopsy of the pleura) do not achieve a precise diagnosis. The percentage of so-called "idiopathic" effusions, amounting to approximately 20% in many published series, can be reduced to 4% after thoracoscopy. The sensibility of thoracoscopic biopsy reaches 93-97% of malignant or tuberculous pleural effusions. The procedure requires a short hospitalization of about 36 hr, and complications are rare. Therapeutic thoracoscopy is frequently performed in chronic, malignant, recurrent effusions in order to achieve a pleurodesis by means of a talc poudrage under visual control. The efficacy of the poudrage in the published randomized studies is better than tetracycline. About 90% of patients are cured, the effusion being totally suppressed. Side effects are rare if the quantity of talc does not exceed 10 ml.

Diagnosis, Differential↗
PubMed1993

Possible regulatory roles of silicic acid, silica and clay minerals in the formation of calcium phosphate precipitates.

The effects of silicic acid, silica and clay minerals on the conversion of amorphous calcium phosphate to hydroxyapatite (HAP) were studied in vitro by a pH drop method. At a concentration range of 0.01-0.1 mM. silicic acid stimulated the rate of HAP transformation by about 30-40%. Silica stimulated the rate of HAP transformation by 33-43% at a concentration range of 0.05-1.5 mg/ml. The clay minerals, i.e. kaolin and talc, also stimulated the rate of HAP transformation by 40-90% at a concentration range of 0.4-10 mg/ml, but mica inhibited the reaction markedly at 10 mg/ml. The distribution of silicon in human supragingival dental calculus was studied by an electron-probe microanalyser. We found localized silicon distribution on the oral surface of the calculus. Such silicon-rich areas always contained silicon either alone or together with magnesium, aluminium, potassium, calcium and iron. This implies that the silicon-rich area may be opal and mica. Because silicic acid, silica, kaolin and talc stimulated and mica inhibited the in vitro calcium phosphate precipitation, it is possible that these silicon-rich areas may regulate the formation of the dental calculus.

Adult↗
PubMed1983

Nonasbestos pulmonary mineral fibers in the general population.

Total pulmonary nonasbestos mineral content was determined for a series of 20 patients who had no occupational dust exposure. To extract mineral fibers, lung tissue was dissolved in bleach and the treated sediment transferred to the electron microscope grid. Mineral fibers were identified using electron diffraction and energy dispersive x-ray spectroscopy. The mean number of nonasbestos fibers, 106 X 10(3)/g wet lung, was almost identical to the mean number of asbestos fibers, 102 X 10(3)/g. Thirteen different species or groups of nonasbestos minerals were found: apatite accounted for 18% of the total and talc for 16%. All other forms accounted for less than 8% each. Silica was found in every lung, and talc in 19 of 20 lungs. Of the fibers, 86% were shorter than 5 microns, and most of the fibers had aspect ratios less than 15. No correlations were seen between numbers or types of fibers and age, sex, or smoking. It is concluded that (1) substantial numbers of nonasbestos fibers are present in lungs of the general population. Most of these fibers are short and of low aspect ratio; and (2) by phase microscopy one is as likely to observe nonasbestos as asbestos fibers in these preparations, indicating that light microscopic methods are not suitable for this type of analysis. These data provide a baseline for comparison with patients believed to have a mineral fiber-related disease.

Adult↗
PubMed1988

Drug-induced and toxic granulomatous hepatitis.

The ability to induce granulomatous hepatitis has been attributed to numerous drugs; some sixty causative drugs have been culled from the literature for this review. Additionally, granulomas or granulomatoid lesions have resulted from occupational exposure to toxic substances (e.g. silica, copper sulphate, beryllium compounds), and particulate material from various therapeutic or diagnostic procedures (e.g. reactions to starch, talc, suture material, polyvinyl pyrrolidone, silicone, barium sulphate, thorium dioxide) or from intravenous drug abuse (e.g. talc). Clinically, patients with drug-induced or toxic granulomatous hepatitis may be asymptomatic. More frequently, the presentation is that of an acute febrile illness, with or without a rash and eosinophilia, followed by jaundice and biochemical evidence of hepatic dysfunction. The diagnosis of drug-induced granulomatous hepatitis is based largely on ruling out other aetiologies. Liver biopsy plays a key role in diagnosis. Recovery is the rule following withdrawal of the drug. Morphologically, drug-induced granulomas may be impossible to distinguish from those due to other causes. Associated lesions suggesting a drug aetiology include significant tissue eosinophilia, unicellular hepatocytic degeneration and necrosis, cholestasis and acute cholangitis or vasculitis. Special stains, polarizing and phase contrast microscopy, transmission and scanning electron microscopy and energy dispersive X-ray microanalysis all play a role in the aetiologic diagnosis of some types of granulomas.

Chemical and Drug Induced Liver Injury↗
PubMed2006

Dose-response study of effect of oleuropein, an olive oil polyphenol, in an ovariectomy/inflammation experimental model of bone loss in the rat.

BACKGROUND & AIMS: This study was carried out to assess the dose-dependent bone-sparing effect of oleuropein, an olive oil phenolic compound with anti-inflammatory and anti-oxidative properties, on bone loss induced by talc granulomatosis in oestrogen-deficient rat. METHODS: Among 98 rats, 20 were sham-operated (SH) while the others (78) were ovariectomised (OVX). The SH and 26 OVX rats (controls) were given a standard diet for 100 days. The 52 remaining OVX rats were allocated to 4 groups that received oleuropein at 2.5, 5, 10 or 15 mg/kg body weight per day for 100 days. Three weeks before necropsy, an inflammation was induced by subcutaneous injections of talc in half of the SH and OVX rats and in all oleuropein-treated animals. RESULTS: Castration was associated with a decreased bone mineral density (BMD). In OVX rats, inflammation, characterised by an increase of the spleen weight and plasma fibrinogen levels, exacerbated this bone loss, as shown by values of BMD of the total femur metaphyseal and diaphyseal subregions. The 4 doses of oleuropein reduced bone loss and improved inflammatory biomarkers excepted for 5mg/kg BW. CONCLUSIONS: Every dose of oleuropein elicited protective effects on bone mass in this model of ovariectomy associated with inflammation, probably by modulating inflammatory parameters.

Animals↗
PubMed2005

Dry coating in a rotary fluid bed.

A highly efficient dry coating process was developed to obtain an enteric film avoiding completely the use of organic solvents and water. Using hydroxypropyl methylcellulose acetate succinate (HPMCAS) an enteric coat should be obtained without adding talc as anti-tacking agent because of problems arising from microbiological contamination. Further on, a method was developed preparing isolated films in order to determine the glass transition temperature (T(g)) and the required process temperature. The process was conducted in the rotary fluid bed with a gravimetric powder feeder achieving an exact dosage in contrast to volumetric powder feeder. A three way nozzle was aligned tangential to the pellet bed movement feeding simultaneously powder and plasticizer into the rotary fluid bed. The determined coating efficiency of the talc-free formulation was high with 94% and storage stability regarding tacking could be achieved using colloidal silicium dioxide as top powder. The T(g) of the enteric coat could be determined analyzing the T(g) of isolated films obtained by coating celluloid spheres instead of pellets using the dry coating process in rotary fluid bed. The dry coating process has been demonstrated to be a serious alternative to conventional solvent or water based coating processes.

Adhesiveness↗
PubMed2004

Influence of selected surfactants on the tackiness of acrylic polymer films.

Anti-tacking agents are always necessary in polymeric film coating formulations in order to prevent substrate agglomeration. The objective of this study was to investigate the abilities of certain nonionic surfactants in a group of sorbitan ester in reducing the tackiness of the films obtained from aqueous acrylic polymer dispersions (Eudragit), compared with those of talc and glyceryl monostearate (GMS). The results from the peel tests demonstrated that GMS, Span 60 and Span 40 could significantly reduce the tackiness of both Eudragit NE 30D and Eudragit RS 30D films. The mechanisms in reducing the film tackiness were investigated by analyzing the film compositions, using attenuated total internal reflectance infrared spectroscopy (ATR-IR) and optical microscopy. The storage modulus of the films was also examined. The results indicated that GMS, Span 60, and Span 40 could reduce the film tackiness by decreasing the polymer contents at the film surfaces, resulting in a notable reduction in the contact area of the polymers between the surfaces. The use of only 5% (w/w) of either GMS, Span 60 or Span 40 in the coating formulations is enough to prevent pellet agglomeration without adverse effects on film flexibility. The pellets coated with Eudragit RS 30D/RL 30D (9:1, w/w) did not exhibit any difference in the drug release profiles when either 100% (w/w) talc or 5% (w/w) GMS was used, whereas the formulations containing Span 60 or Span 40 gave a slightly faster release rate.

Polymethacrylic Acids↗
PubMed2006

Effect of grinding and heating on Ni2+ uptake properties of waste paper sludge.

Uptake properties of Ni2+ were examined for unmilled and milled paper sludge calcined at various temperatures to develop a new usage of waste paper sludge. Since paper sludge mainly consists of cellulose ([C6H(10)O5]n) fibers, calcite (CaCO3), kaolinite (Al2Si2O5(OH)4) and talc (Mg3Si(4)O(10)(OH)2), amorphous and crystalline CaO(MgO)-Al(2)O(3)-SiO(2) compounds are formed by calcining paper sludge. Wet and dry milling treatments were performed to accelerate solid-state reaction to form the above mentioned target compounds. The crystalline phases originally present decompose at increasing calcining temperature (up to 800 degrees C) in the order cellulose <kaolinite <calcite <talc. An amorphous phase was formed in the samples below 800 degrees C and the temperatures changed depending on the milling conditions in the order dry milled <wet milled <unmilled. Gehlenite (Ca(2)Al(2)SiO(7)) and anorthite (CaAl(2)Si(2)O(8)) crystallized by calcining at 900 degrees C in all the samples, formed by solid-state reaction of kaolinite with calcite. The (29)Si and (27)Al MAS NMR spectra of the amorphous samples were similar to those of crystalline phases, suggesting that the local structure of the amorphous phase resembles the crystalline structures. Maximum Ni2+ uptake occurred in the dry-milled samples calcined at 600 degrees C, and wet-milled and unmilled samples calcined at 700 degrees C, respectively. The dry-milled and calcined at 600 degrees C sample showed the highest Ni2+ uptake (4.54 mmol/g) and an uptake rate of 3.5 micromol/(gmin).

Adsorption↗
PubMed1987

Mineral particles in the lungs of subjects resident in the Rome area and not occupationally exposed to mineral dust.

We studied the inorganic particulate contained in the lung parenchyma of 10 subjects (5 males and 5 females) resident in an urban area and not occupationally exposed to dusts. A total of 17 mineral types were identified, along with 16 metal elements in the form of oxides and sulfides. Approximately 70% of the minerals were made up of phyllosilicates, in particular clay, mica, and talc; three metal elements, Fe, Al, and Ti, accounted for more than 75% of the recovered oxide particles. The mean concentration of the observed inorganic particles was approximately 1.8 X 10(5) pp/mg dry tissue. No significant differences were observed in terms of total particulate concentration in the various areas of the lungs and between the right and left lung. Instead we observed a larger concentration of fibrous particles in the upper lobes. The analysis of the data made it possible to determine the presence of a high degree of correlation between the concentrations of silicates and the concentrations of metal oxides and sulfides, implying the existence of a ubiquitous environmental source of these mineral particles. The frequent observation of tremolite fibers is remarkable. This finding, confirmed elsewhere, indicates that the magnitude of the sources of these fibers in the environment, constituted by contaminated talc dusts, has been underestimated until today.

Aged↗
PubMed2003

Thoracoscopic treatment of spontaneous pneumothorax in children.

BACKGROUND/PURPOSE: This study describes the authors experience and results with thoracoscopic treatment of spontaneous pneumotrorax (SP) in 22 children. METHODS: A total of 32 thoracoscopic procedures were performed in 22 children. The patients ranged in age from 9 to 21 years at the time of their first thoracoscopy. SP was primary in 9 and secondary in 13 patients. Pleurodesis was performed in all thoracoscopies using talc in 28 and pleural abrasion in 4 procedures. In 2 of these, apical pleurectomy was added to abrasion. Blebectomy was the additional surgical procedure associated with pleurodesis in 4 patients. RESULTS: Thoracoscopy usually was performed with the patient under general anesthesia. In children with severe respiratory insufficiency, regional anesthesia was used. The mean operative time was 42.6 minutes (range, 8 to 114 minutes). The mean time of postoperative chest tube drainage was 4.6 days (range, 2 to 12 days). Three patients with cystic fibrosis had prolonged air leak lasting longer than 7 days after thoracoscopy. None of them required an additional surgical intervention, and the air leak ceased in 8, 8, and 12 days with continuous suction. One patient required a repeat thoracoscopy for bleeding from an intercostal artery on postoperative day one. The mean follow-up was 4 years (range, 2.5 months to 14 years). There have been 2 partial recurrences (6.25%), both in patients with secondary SP, which were treated by a repeat thoracoscopy and talc pleurodesis. CONCLUSIONS: Thoracoscopic treatment of SP is safe and effective in children. It can be performed under regional anesthesia also in children with severe respiratory insufficiency. Because the complications and recurrences are encountered more frequently in children with an underlying lung disease, special care in surgical manipulation is required in this subgroup of patients with SP.

Adolescent↗
PubMed1999

Impact of the surface slipperiness of grasped objects on their subsequent acceleration.

Seven subjects were asked to reach and grasp an object between the thumb and index finger, lift it about 30 cm high and 25 cm forward from one table to another, at their preferred speed. The perpendicular grip force and the tangential load force applied to the contact surface were digitized at 500 Hz and stored on a laboratory computer. The trajectory of the wrist and of the object was recorded using four infrared cameras tracking the movement of reflective markers attached to the distal styloid process of the radius and on the top of the object. The aim of this study was to demonstrate the influence of low friction (i.e. surface slipperiness) on the acceleration of the wrist. Friction was reduced by coating the smooth brass grasping surface with talc. The seven subjects had skin to surface coefficients of friction which ranged from 0.52-1.18 for dry brass and 0.24 0.34 for talc-coated brass. Two weights (418 and 1070 g) were used with each surface. The results indicated that with the slippery surface the necessary higher grip force/load force ratio was produced by an increase in the grip force and by a decrease in the wrist acceleration and a consequent reduction in the load force. This strategy was observed for both weights over a range of grip strengths between 21-98% of the individual's maximum voluntary contraction (MVC). This implies that even with adequate grip force reserves the reduction in acceleration is an acceptable and probable alternative solution to the force control problem. Our results also suggested that the loading rate and the object acceleration were planned and controlled together which emphasizes the role played by a predictive mechanism in organizing the kinematics of movements involving hand-held objects. This study shows that friction of the grasping surface not only affects the prehensile force dynamics, but it also influences the kinematics of the entire upper limb.

Acceleration↗
PubMed1982

Pathology of cystoid macular edema.

In order to define the pathology of cystoid macular edema (CME), 35 human cases with histopathologic features of CME were reviewed. The macular cysts appeared in different layers of the retina in eyes after cataract extraction, retinal vein occlusion, trauma, diabetes mellitus, and accelerated hypertension. The pathologic process varied from transudation, exudation to liquefaction necrosis. The experimental models of lens extraction and talc retinopathy in rhesus monkeys were examined. Disruption of the blood-retinal barrier at the retinal vasculature and retinal pigment epithelium were noted after lens extraction. Cystoid degeneration of the macula was seen in monkeys with talc retinopathy. The possibility that disruption of the blood-retinal barrier and microinfarction play important roles in the formation of the macular cysts is proposed.

Aged↗
PubMed1997

Mechanisms of adjuvancy: I--Metal oxides as adjuvants.

The exact mechanism of how immune adjuvants function still remains largely unknown, despite their long history of use. This work reports the properties of alum and the related compounds Al(OH)3 or Al2O3. Experiments were performed in rats to determine the relative adjuvancy of silica, talc, ground glass, Al2O3, SnO2, ZrO2, hematite and magnetite. Antibody response and cell-mediated immunity (CMI) to ovalbumin (OVA) were determined and were found to be significantly enhanced by silica and talc. Antibody response to OVA was moderately enhanced by Al2O3, hematite, and magnetite, while CMI to OVA was not affected, SnO2, ZrO2, and ground glass only gave a slight adjuvant effect. The magnitude of adjuvancy appeared to correlate with the magnitude of the inflammatory response produced by each metal oxide and also correlated with their surface area. No correlation could be drawn between the hydrophilicity or hydrophobicity of the metal oxides and the magnitude of their adjuvancy.

Adjuvants, Immunologic↗
PubMed2002

Stabilization of amorphous indomethacin by co-grinding in a ternary mixture.

Mechanochemical amorphization of indomethacin (IM) was substantially enhanced by grinding with SiO(2), talc and a Mg(OH)(2)-SiO(2) mixture. The rates of the mechanochemical amorphization were in the order of Mg(OH)(2)-SiO(2) mixture>talc>SiO(2). Amorphous state stability of IM compounded with the carrier was examined by crystallization behavior under the condition of 30 degrees C and 11% relative humidity. Superiority of the binary mixture as a carrier was explained in terms of the mechanically induced strong acidic sites of the carrier.

Calorimetry, Differential Scanning↗