Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Talc”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources
PubMed1999

In situ observation of the formation of 10 A phase from talc + H(2)O at mantle pressures and temperatures

Development of an x-ray-transparent capsule that is suitable for water-saturated experiments has allowed the high-pressure and high-temperature synthesis of 10 angstrom phase from talc + H(2)O to be observed in situ in a multianvil apparatus with synchrotron radiation. The reaction talc + H(2)O = 10 angstrom phase was observed within 20 minutes at 6 gigapascals and 500 degrees C. The higher pressure vapor-absent reaction talc = 10 angstrom phase + enstatite + coesite was also observed. The 10 angstrom phase is therefore a good candidate for transporting water into Earth's mantle at subduction zones. The in situ technique may allow the hydration of other high-pressure mantle phases to be observed under dynamic conditions.

Journal Article↗
PubMed1979

Talc emboli and macular ischemia in intravenous drug abuse.

A patient with decreased visual acuity had small, glistening white particles that were scattered over both posterior poles. Monochromatic fundus photography revealed ghost vessels and intraluminal particulate matter in small retinal vessels. Fluorescein angiography demonstrated nonperfusion of small arterioles and macular capillaries. The patient admitted to multiple intravenous injections of crushed methylphenidate (Ritalin) hydrochloride tablets, which contain talc 18 months prior to examination. To our knowledge, visual loss and irreversible macular ischemia from talc emboli have not been previously documented.

Adult↗
PubMed1982

Talc retinopathy in primates: a model of ischemic retinopathy. III. An electron microscopic study.

Electron microscopic study of experimental talc retinopathy provides an opportunity to study the basic cytologic response of retinal and choroidal vessels to small, relatively inert emboli. Occlusion of the retinal and choroidal capillaries resulted primarily from the cellular reaction to, rather than directly from, the emboli. Mitotic figures in pericytes were observed. Even though we failed to produce retinal neovascularization (as is sometimes seen in human talc retinopathy) in this experimental model, our observations suggest that proliferation of pericytes may be an initial step in the process of retinal neovascularization.

Animals↗
PubMed1978

Talc granuloma of the ureter: a case report.

A patient presented with symptoms of ureteric colic. At laparotomy a ureteric stricture was found which was presumed to be tuberculous, but histological examination proved it to be a talc granuloma, the talc having been introduced as a glove powder 20 years previously during a hysterectomy operation.

Female↗
PubMed1993

Hair dyes, analgesics, tranquilizers and perineal talc application as risk factors for ovarian cancer.

In a hospital-based case-control study of ovarian cancer conducted in Athens (1989-1991), 189 women with histologically confirmed common malignant epithelial tumors of the ovary were compared with 200 hospital visitor controls. All interviews were conducted by personal interview in the 2 participating hospitals and the data were analyzed by modelling through logistic regression, controlling for demographic and reproductive variables. Tranquilizing and hypnotic drugs (mostly diazepam) were not associated with risk of ovarian cancer: the adjusted relative risk (RR) and 95% confidence interval (CI) were 0.96 (0.57 to 1.63), whereas use of analgesics (mostly salicylates) was associated with significantly reduced risk of the disease (RR 0.51; CI 0.26 to 1.02). There was no evidence that perineal application of talc was associated with increased risk (RR 1.05; CI 0.28 to 3.98) but the frequency of reporting talc use was low in the study population. There was a statistically significant (p for trend 0.007) and a dose-dependent association between hair dyeing and risk of ovarian cancer. Compared to never-users, women dyeing their hair up to 4 times per year had a relative risk of 1.74 (0.91 to 3.32) whereas those dyeing their hair 5 or more times per year had a relative risk of 2.16 (1.19 to 3.89).

Adult↗
PubMed1981

Polymorphism of spray-dried microencapsulated sulfamethoxazole with cellulose acetate phthalate and colloidal silica, montmorillonite, or talc.

Sulfamethoxazole was microencapsulated with cellulose acetate phthalate and talc, colloidal silica, or montmorillonite clay by a spray-drying technique. The surface topography of the products varied with the type of excipient used and the pH of the suspending medium. The products without the excipient were coated with flake-like crusts, while the products containing the excipient tended to become well-rounded spheres. In addition, the crystalline form of sulfamethoxazole converted from Form I to an amorphism and Form II during the spray-drying process. This polymorphic transformation was attributed to the interaction of cellulose acetate phthalate with sulfamethoxazole. Increasing the concentration of cellulose acetate phthalate in the formulation increased the attainment of amorphism. Form II was also obtained by freeze and vacuum drying. Talc was the only excipient that contributed to polymorphism, which occurred in the alkaline suspension medium. Montmorillonite products prepared from the acidic medium exhibited an exothermic differential scanning calorimetry thermogram, which might be interpreted in terms of adsorption of the fused sulfamethoxazole with the internal surface of montmorillonite,

Bentonite↗
PubMed1993

Role of 1,25-dihydroxyvitamin D3 in the generation of the acute-phase response in rats with talc-induced granulomatosis.

Subcutaneous injection of nonspecific irritants such as magnesium silicate (talc) provokes granulomatous inflammation in the rat. Part of the acute phase response (APR) in these animals is the loss of trabecular bone at sites distant from the site of inflammation. To assess the possible involvement of vitamin D in the bone loss, we studied the development of the acute phase response in vitamin D-deprived rats. The serum APR provoked by subcutaneous inflammation in rachitic rats consisted of hypozincemia, hypercupremia, increased alkaline phosphatase activity and adrenocorticotropic hormone (ACTH) concentration, and was similar to that in control animals except for the absence of hypoferremia. Control rats with talc-induced subcutaneous inflammation also had splenomegaly and decreased total and mononuclear peripheral blood cell counts, while subcutaneous inflammation did not induce spleen changes in rachitic rats. Subcutaneous inflammation induced the loss of trabecular bone and decreased the osteoblastic cell count in tibial metaphyses in control animals. Rachitic rats had abundant osteoid on trabecular surfaces, and the number of osteoblasts and osteoclasts was comparable to that of the controls. Subcutaneous inflammation did not affect any of the bone parameters in rachitic rats. These results indicate that vitamin D plays an important role in the generation of the acute phase response during inflammation, particularly in the induction of spleen and bone cell changes. The discrepancy of the blood on one hand and bone and spleen indices of the APR on the other, indicate that they may be divergent pathways in the generation of the inflammatory response, some of which may be dependent on vitamin D.

Acute-Phase Reaction↗
PubMedDate not supplied

Pleurodesis induced by talc or silver nitrate: evaluation of collagen and elastic fibers in pleural remodeling.

This study evaluated the extracellular matrix (collagen and elastic fibers) in pleurodesis induced by intrapleural talc (TL) or silver nitrate (SN). Study subjects were 420 rabbits divided into two groups and sacrificed from 15 min to 12 months after the injection of the sclerosing agents at intervals previously defined. Pleural adhesions and fibrosis were graded (0-4), and the collagen and elastin were quantified. The maximum score of the pleural adhesions was observed two months after TL (2.80 +/- 0.99) and 15 days after SN (3.75 +/- 0.25). More intense pleural adhesions were observed in the SN group from day 5 (p < 0.05). Pleural thickness and pleural fibrosis were, in general, significantly higher after SN (p < 0.05). Increased deposition of collagen and elastin was observed in both groups but was more evident in the SN group. In the TL group, a linear correlation was observed between pleural adhesions and fibrosis (r = 0.775), between pleural adhesions and collagen (r = 0.779), and between fibrosis and collagen (r = 0.709). In the SN group, these correlations were acceptable (r = 0.605, 0.665, and 0.663). The elastin presented a correlation of 0.707 (p < 0.001) in the TL group and of 0.564 (p < 0.001) in the SN group. In conclusion, intrapleural 0.5% silver nitrate and talc (400 mg/kg) are effective in the induction of pleurodesis. However, the intensity of adhesions and the richness of collagen after SN, in combination with the early onset of tissue remodeling, demonstrate the local superiority of this agent. Considering the easy availability and instillation, the low cost, and the absence of important side effects, silver nitrate might be considered as a sclerosing agent to induce pleurodesis in humans.

Animals↗
PubMed1990

Thoracoscopy and talc poudrage for pneumothoraces and effusions.

The indications, technique, and results of thoracoscopic talc poudrage in the two clinical settings of pneumothorax and recurrent pleural effusion in chronically ill patients are reported. Forty patients underwent this treatment between May 1982 and September 1989. The patients ranged in age from 10 months to 78 years. Of the 20 patients who underwent treatment of pneumothorax, 9 had cystic fibrosis, 7 had severe chronic obstructive pulmonary disease, 2 had spontaneous pneumothoraces, and 2 had postoperative parenchymal bronchopleural fistulas. Nineteen patients (95%) had successful treatment. Of the 20 patients who underwent treatment of chronic effusions, 14 had malignant etiologies, 3 had chylothoraces, and 3 had other miscellaneous effusions. Eighteen patients (90%) in this group had successful treatment. There were two hospital deaths related to the underlying disease processes after the pleural space problems were successfully treated. This study suggests that proper selection of patients and full exploitation of the capabilities of thoracoscopy and talc poudrage will result in effective treatment with low morbidity and mortality.

Cystic Fibrosis↗
PubMed1994

Stabilization of potato tuber lipoxygenase on talc.

Potato tuber lipoxygenase, like many plant enzymes is a very labile protein and can lose activity during or after the purification procedure. In order to overcome this problem, we immobilized potato tuber lipoxygenase by adsorption on talc, a silicate support. Lipoxygenase adsorption greatly increased the long-term stability of the enzyme without modifying enzyme specificity. Moreover, adsorption on talc could be used to purify labile enzymes whose enzymatic activity decreases rapidly during purification stages. A multi-step reaction to produce large quantities (around 100 mg) of fatty acid hydroperoxides without enzyme inactivation was developed.

Adsorption↗
PubMed2006

Efficacy of short-term versus long-term chest tube drainage following talc slurry pleurodesis in patients with malignant pleural effusions: a randomised trial.

Talc pleurodesis is commonly used in the palliative treatment of malignant pleural effusions but the shortest and most effective regime has not been determined. In particular, it is not clear when the intercostal drain should be removed following the insertion of sclerosant. We conducted a single-centre, randomised, open trial of drain removal at 24 h versus 72 h following talc slurry pleurodesis. The primary outcome measure was success of pleurodesis (no recurrence of effusion on chest radiograph at 1-month follow-up) and secondary outcome measures included length of hospital stay and mortality. We found no difference between recurrence of pleural effusion in those randomised to drain removal at 24 h and those randomised to drain removal at 72 h (p>0.5). However, length of stay was significantly reduced when the chest drain was removed at 24 h (4 days versus 8 days; p<0.01). Mortality did not differ between the two groups. We conclude that this shorter pleurodesis regime is safe and effective.

Adult↗
PubMed1997

Talc embolism: a static retinopathy.

PURPOSE: To document the static nature of crystalline deposits in talc retinopathy. METHOD: Case report. RESULTS: A 38-year-old woman with a remote history of intravenous drug abuse showed the incidental finding of fine, irregularly shaped refractile deposits in the retinal microvasculature. At 2-year follow-up, fundus findings were identical to the initial manifestation with respect to the distribution and position of crystalline deposits in each fundus. CONCLUSION: This case documents the static nature of crystalline deposits in talc retinopathy.

Adult↗
PubMed1980

Talc retinopathy.

Twenty-three patients had bilateral intraretinal talc microemboli, which were seen on ophthalmoscopic examination. Twelve of these patients had additional retinal vascular or choroidal abnormalities in the posterior pole that were confirmed by fluorescein angiography. Six patients had peripheral retinal neovascularization associated with peripheral retinal vascular nonperfusion. Of these six patients, three had associated vitreous hemorrhage, and two had optic disk neovascularization and traction retinal detachment. The progressive fundus changes seen in talc retinopathy were documented by fluorescein angiography and compared to those seen in sickle-cell retinopathy. One eye in one patient was treated by argon laser photocoagulation for proliferative retinopathy, and three eyes in two patients with vitreous hemorrhage were treated by pars plana vitrectomy.

Adult↗
PubMed2003

Chronic pain due to talc pleurodesis for spontaneous pneumothorax.

Spontaneous pneumothorax is a common condition that usually affects young adults. Talc insufflation, either as a poudrage or by using slurry, is recognized as an effective treatment. We report a case of talc that resulted in chronic debilitating pain and necessitated further surgery.

Adult↗
PubMed1977

Dissolution of silicic acid from dusts of kaolin, mica and talc and its relation to their hemolytic activity. -- an in vitro study.

Hemolysis induced by native kaolin dust was found to run parallel to the amount of silicic acid dissolved from it. Native mica and talc dusts were hemolytic only to a small extent and the silicic acid dissolution from these dusts was also smaller in comparison to that of native kaolin. The proportionality between hemolysis and the amount of dissolved silicic acid was not consistently observed in the case of acid, alkali and water treated kaolin, mica and talc dusts.

Animals↗
PubMed1977

Talc granuloma presenting as a testicular mass.

A case of a benign talc granuloma in a 3-year-old boy is reported. Surgical wound contamination with various lubricant dusts from surgeons' gloves and resultant granuloma formation is a well known phenomenon. However, there are few reported cases of peritesticular masses owing to talc granulomas.

Child, Preschool↗
PubMed1999

Perineal talc exposure and subsequent epithelial ovarian cancer: a case-control study.

OBJECTIVE: To evaluate the role of talcum powder use as a risk factor for the development of epithelial ovarian cancer. METHODS: In a case-control study, 499 patients with epithelial ovarian cancer were frequency matched for age at diagnosis (-5 years) with a control population of 755 patients. The odds ratio (OR) for the development of epithelial ovarian cancer was estimated using logistic regression analysis with adjustment for age at diagnosis, parity, oral contraceptive use, smoking history, family history of epithelial ovarian cancer, age at menarche, menopausal status, income, education, geographic location, history of tubal ligation, and previous hysterectomy. RESULTS: Two hundred twenty-one of 462 patients (47.8%) in the study population and 311 of 693 patients (44.9%) in the control population had ever used talcum powder (OR 0.92; 95% confidence interval [CI] 0.24, 3.62). A significant association between duration of talc use and development of epithelial ovarian cancer was not demonstrable for 1-9 years (OR 0.9; 95% CI 0.6, 1.5), for 10-19 years (OR 1.4; 95% CI 0.9, 2.2), or for more than 20 years (OR 0.9; 95% CI 0.6, 1.2). To eliminate the possible confounding variable of surgery for the management of ovarian cancer, we omitted 135 patients in the study population who underwent hysterectomy within 5 years of the diagnosis of ovarian cancer. Within this subgroup of patients, tubal ligation or hysterectomy among talc users still failed to demonstrate an increased risk for the development of ovarian cancer (OR 0.9; 95% CI 0.4, 2.2). CONCLUSION: A significant association between the use of talcum powder and the risk of developing epithelial ovarian cancer is not demonstrable, even with prolonged exposure.

Case-Control Studies↗