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PubMed2007

Interaction with intraocular lens materials: does heavy silicone oil act like silicone oil?

PURPOSE: To determine the interaction of heavy silicone oil with various intraocular lens (IOL) materials and whether heavy silicone oil covers the silicone IOL optic as silicone oil does. SETTING: Department of Ophthalmology, Dokuz Eylul University, Izmir, Turkey. METHODS: The study group comprised 5 poly(methyl methacrylate) (PMMA) IOLs, 4 foldable silicone IOLs, 5 foldable hydrophilic acrylic IOLs, and 5 foldable hydrophobic acrylic IOLs. Each IOL was bathed in balanced salt solution (BSS) for 10 minutes and then placed in heavy silicone oil dyed with Sudan Black for another 10 minutes. Afterward, each IOL was reimmersed in BSS for 5 minutes and examined under the light microscope. Digital images were analyzed to determine the optic area covered with heavy silicone oil. RESULTS: The mean heavy silicone oil coverage was 7.05% +/- 7.88% (SD) (range 1.13% to 20.54%) on PMMA IOLs, 100% on silicone IOLs, 12.17% +/- 11.43% (range 1.25% to 31.52%) on hydrophobic acrylic IOLs, and 34.64% +/- 13.28% (range 12.57% to 44.42%) on hydrophilic acrylic IOLs. Heavy silicone oil coverage of silicone IOLs was statistically significantly greater than the coverage of other IOL materials. CONCLUSION: Heavy silicone oil acted the same as silicone oil and covered the entire surface of silicone IOLs.

Acrylic Resins↗
PubMedDate not supplied

The non-specific binding of immunoglobulins to silicone implant materials: the lack of a detectable silicone specific antibody.

Recent studies have suggested that anti-silicone antibodies develop in patients implanted with silicone materials. The majority of these studies have utilized enzyme-linked immunosorbent assay (ELISA) methodology with a silicone material substrate as a means to detect the presence of the anti-silicone antibody. The current studies were undertaken to determine whether the binding of IgG to a silicone substrate was consistent with an antigen-specific antibody interaction or the result of non-specific hydrophobic interactions. While significant differences were detected in serum from silicone antibody "positive" and "negative" patients when the ELISA was conducted using a phosphate buffered saline (PBS)-0.05% Tween 20 (Tween) blocking system, the difference in the responses was attenuated when protein blocking systems were used or when incubation times were decreased. Furthermore, ELISA studies, using purified mouse and human IgG, demonstrated a concentration-dependent binding of IgG to silicone elastomer substrate which was also attenuated when a protein blocking system was used in lieu of Tween. In controlled animals studies in which female B6C3F1 mice were implanted with silicone gel or silicone elastomer for 180 days, no difference was observed between the implanted animals and the PBS control animals with respect to binding of IgG to the silicone substrate. Similar studies in female Fischer 344 rats implanted with silicone gel for 84 days also failed to demonstrate the presence of anti-silicone antibody. Collectively, the results suggest that the binding of IgG to silicone implant materials is non-specific in nature, consistent with the well-recognized interactions between hydrophobic molecules (IgGs) and hydrophobic surfaces (silicones) in an aqueous-based system.

Animals↗
PubMed1993

Demonstration of silicon in sites of connective-tissue disease in patients with silicone-gel breast implants.

BACKGROUND AND DESIGN: Silica, Silastic, and silicone (any organic compound in which silicon replaces carbon) have been associated with a number of connective-tissue diseases, most commonly systemic sclerosis (scleroderma). Silicone is known to leak from breast implants and spread to surrounding tissues, including lymph nodes, but silicone's role in the origin and pathogenesis of the inflammation and fibrosis related to such conditions remains controversial. Synovial tissue, alveolar macrophages, and skin, each from three different patients with silicone-gel implants, plus the breast implant capsules from each of the three patients, were examined by light microscopy, transmission electron microscopy, and electron probe microanalysis for the presence of silicon-containing material. RESULTS: Silicon was identified within the fibrous breast capsule of each case, associated with a chronic inflammatory cell infiltrate. Silicon was also identified within tissues involved by chronic inflammation and fibrosis, namely, synovium, skin, and alveolar macrophages, in association with clinical, serologic, and histologic evidence of connective tissue disease. All three patients improved after removal of the silicone-gel breast implants. CONCLUSIONS: The presence of silicon-containing material within sites of connective-tissue disease supports a role for silicon in the origin or pathogenesis of such conditions in patients with silicone-gel breast implants. All patients with connective-tissue disease should be questioned about exposure to various forms of silicon. In those patients with known exposure, tissue specimens should be examined carefully for silicon-containing material and, if found, the source should be removed.

Adult↗
PubMed1987

Effect of dietary silicon and aluminum on silicon and aluminum levels in rat brain.

This preliminary study was undertaken to investigate the effect of dietary silicon and aluminum on levels of these elements in brain. Two ages of rats, 22 day and 10 month, were assigned to 1 of 4 diets: 1) low silicon; 2) low silicon plus aluminum; 3) silicon supplemented; and 4) silicon supplemented plus aluminum. Rats were 23 and 28 months old upon termination of the experiment. Twelve brain regions were analyzed for silicon and aluminum. Regional variations in silicon, which were independent of dietary silicon supplementation, suggest that silicon may be an essential element in brain. Aluminum supplementation decreased the silicon content in selected brain regions, including those thought to be involved in Alzheimer disease. A relationship has been established between silicon, aluminum and age. In 23-month rats, aluminum supplementation did not increase brain aluminum content. By contrast, in 28-month rats, aluminum supplementation of the low silicon diet increased brain aluminum content in most regions. No increase occurred in silicon supplemented groups of the same age. Dietary silicon supplementation thus appeared to be protective against aluminum accumulation in aging brain.

Aging↗
PubMed1995

Increased silicon levels in dialysis patients due to high silicon content in the drinking water, inadequate water treatment procedures, and concentrate contamination: a multicentre study.

BACKGROUND: Although silicon is considered as an essential element, little is known about the basic effects and clinical significance of increased concentrations of the element in dialysis patients. METHODS AND RESULTS: In a multicentre study we found silicon levels in haemodialysis (HD) patients to be markedly increased. In these patients silicon concentrations were significantly higher than those noted in subjects with normal renal function as well as in patients with chronic renal failure not yet in dialysis and patients treated by continuous ambulatory peritoneal dialysis (CAPD). Moreover we noted that in both HD and CAPD patients mean silicon levels differed from one centre to another. Also, was there in the HD population a significant difference in serum silicon levels among patients from different countries. In HD patients differences in serum silicon levels were either due to the use of silicon contaminated dialysis fluids or an increased oral intake of the element mainly originating from the high silicon content of the drinking water. Silicon contamination of the dialysis fluid was found to be due to either the use of reverse osmosis membranes that insufficiently retain the element during water treatment or by the addition of concentrates containing high amounts of silicon. Using a recently developed high-performance liquid chromatographic/atomic absorption spectrophotometric (HPLC/ETAAS) hybrid technique, we found silicon in serum to be present as a low-molecular-weight non-protein-bound component, which in the presence of a low silicon dialysate is adequately removed during treatment. CONCLUSIONS: The clinical relevance of increased serum silicon levels is not yet known and as such deserves further investigation. In view of the controversy that exists on the element's assumed protective as well as toxic role in the development of some (aluminium-related) neurodegenerative diseases and its vital role in bone formation, monitoring of the silicon levels in serum, tap water, and dialysis fluids might become important.

Aluminum↗
PubMed1996

The adjuvant effect of silicone gel and silicone elastomer particles in rats.

This study examines the adjuvant properties of silicone oil, silicone gel and silicone elastomer using a foreign antigen, bovine serum albumin (BSA). Seventy male Harlan Sprague-Dawley rats, approximately 250 grams each, were divided into 7 groups: A- incomplete Freund's adjuvant (IFA) with BSA; B- silicone oil with BSA; C- IFA/silicone oil with BSA; D- 50% silicone gel/50% silicone oil with BSA; E- silicone oil/1000 microns elastomer particles with BSA; F- silicone oil/500 microns elastomer particles with BSA; G- saline with BSA. Rats were implanted intramuscularly with mixtures or emulsions of the above described treatment materials. Cardiac punctures were performed on days 0, 14, 28, 42, and 55. Serum IgG antibody response to BSA was determined by enzyme-linked immunosorbent assay (ELISA). Rats were sacrificed on day 55 and sections of the injection sites were collected and stained for histopathologic evaluation. The results demonstrated that silicone gel functions as a potent immunologic adjuvant as measured by a heightened IgG antibody response to BSA. In contrast silicone elastomer particles have no apparent adjuvant effect as determined by the low anti-BSA antibody levels in these treatment groups throughout the course of the study. Histologically, silicone gel and silicone elastomer elicit a moderate to severe "foreign body" granulomatous inflammatory response at the injection site. Silicone oil elicits mild or no local inflammatory response.

Adjuvants, Immunologic↗
PubMed1993

Silicon and silicone: theoretical and clinical implications of breast implants.

In the past 10 years, there have been multiple published reports associating silicone breast implants with scleroderma, morphea, SLE, rheumatoid arthritis, CREST syndrome and "human adjuvant disease." The alleged offending material, silicone, is a synthetic polymer containing a silicon-oxygen backbone. Beginning with the heating of SiO2 in the presence of carbon, elemental silicon is produced. Methylchloride is added and the resulting product is hydrolyzed to form low molecular weight prepolymers which are linked to form linear silicone polymers and cross-linked to yield silicone rubbers or elastomers. The polymeric and hydrophobic characteristics of silicone and the presence of electrostatic charges and organic sidegroups make silicone a potentially ideal immunogen, leading to cross-reactivity with autoantigens. Silicon is an essential constituent of proteoglycans which theoretically could result in immunological cross-reactions between silicone and connective tissues. Although the literature contains numerous examples of silicone-associated autoimmune disease, there is no consistent pattern of immunological abnormalities observed. There are, however, some intriguing and interesting observations. Further large-scale studies are needed to determine if a link between silicone exposure and autoimmunity exists. Also, since the inducing events of autoimmune diseases are unknown, studies on silicone could provide a model for autoimmune diseases associated with toxicological factors.

Adult↗
PubMed1997

Interaction between silicone oil and silicone intraocular lenses: an in vitro study.

The objective of this study was to examine the interaction between silicone oil and silicone intraocular lenses (IOLs) in vitro. Six types of silicone IOLs were placed in silicone oil (1000 or 5000 centistokes) for 1 minute, 7 days, and 420 days. Slit-lamp examination, target photographs, and opacity measurements were performed. Optical measurements were repeated in a balanced salt solution after removal from the oil. The IOL surface was examined through scanning electron microscopy, and surface irregularities underwent x-ray spectroscopy. No changes were observed while the IOLs were stored in silicone oil, but in the balanced salt solution, the IOLs were observed to have a layer of silicone oil droplets that reduced the optical quality. Scanning electron microscopy showed that oil-coated foreign body particles were simulating IOL surface defects. After ultrasonic cleaning with ethanol, the oil layer was broken, and no damage to the IOL surface could be detected. The length of exposure to silicone oil, the type of oil, and the type of IOL were found to have no bearing on the interaction between silicone oil and silicone IOLs. Although no surface damage is incurred by silicone IOLs from silicone oil, the reduction in optical quality and fundus view due to remnant oil droplets seems to indicate that complex cases requiring silicone oil injection may contraindicate IOLs made of silicone.

Adhesiveness↗
PubMed2004

Characterization of the silicon uptake system and molecular mapping of the silicon transporter gene in rice.

Rice (Oryza sativa L. cv Oochikara) is a typical silicon-accumulating plant, but the mechanism responsible for the high silicon uptake by the roots is poorly understood. We characterized the silicon uptake system in rice roots by using a low-silicon rice mutant (lsi1) and wild-type rice. A kinetic study showed that the concentration of silicon in the root symplastic solution increased with increasing silicon concentrations in the external solution but saturated at a higher concentration in both lines. There were no differences in the silicon concentration of the symplastic solution between the wild-type rice and the mutant. The form of soluble silicon in the root, xylem, and leaf identified by (29)Si-NMR was also the same in the two lines. However, the concentration of silicon in the xylem sap was much higher in the wild type than in the mutant. These results indicate that at least two transporters are involved in silicon transport from the external solution to the xylem and that the low-silicon rice mutant is defective in loading silicon into xylem rather than silicon uptake from external solution to cortical cells. To map the responsible gene, we performed a bulked segregant analysis by using both microsatellite and expressed sequence tag-based PCR markers. As a result, the gene was mapped to chromosome 2, flanked by microsatellite marker RM5303 and expressed sequence tag-based PCR marker E60168.

Biological Transport, Active↗
PubMed1995

The effect of molecular weight and gel preparation on humoral adjuvancy of silicone oils and silicone gels.

Silicone gels from commercial breast implants have been shown previously by our laboratory to be potent humoral adjuvants, while the low molecular size 20 centistoke (cs) silicone oil (M.W. 1900) possesses no measurable adjuvant properties. It became necessary to shear the silicone gel during our previous experiments in order to facilitate injection through a syringe and needle, it is conceivable that shearing may reduce the molecular weight of the silicone gel used. This investigation was undertaken to determine whether humoral adjuvancy of silicone oils is dependent on molecular weight and whether the method of shearing the silicone gel affects its adjuvancy. Four Dow Corning 360 Medical silicone oils (100 cs, M.W. approximately 5,000; 350 cs, M.W. approximately 10,000; 1000 cs, M.W. approximately 16,500 and 12,500 cs, M.W. approximately 60,000) and Dow Corning octamethylcyclotetrasiloxane (D4, M.W. 296) were tested for their humoral adjuvancy by immunizing 64 Sprague Dawley rats with 50 micrograms of bovine serum albumin (BSA) mixed with each oil. The rats were periodically bled and the sera were analyzed for anti-BSA antibodies by ELISA. In a separate experiment, three silicone gel preparations with reproducible characteristics were prepared by using a tissue homogenizer and varying the applied shear force. Each of these preparations was tested for its humoral adjuvancy as previously described for silicone oils. Rats immunized with BSA mixed with the highest molecular size silicone oil tested (M.W. approximately 60,000) showed a significant increase in anti-BSA antibodies as compared to the lower molecular size oils. The three silicone gel preparations showed no difference in their adjuvancy effect. Thus, the humoral adjuvancy of silicone oil appears to be dependent on molecular weight. Differential shearing of the silicone gel does not alter its humoral adjuvancy.

Adjuvants, Immunologic↗
PubMed1999

Comparison of a silicone gel-filled cushion and silicon gel sheeting for the treatment of hypertrophic or keloid scars.

BACKGROUND: The exact mechanisms of action responsible for the effectiveness of silicone gel dressings are unknown, although it has been proposed that static electricity generated by friction could be the reason for their anti-scarring effects. OBJECTIVE: We compared the efficacy of a cushion of silicone filled with liquid silicone gel reported to induce greater negative static-electric charge with silicone gel sheeting in the treatment of hypertrophic and keloid scars. METHODS: The size, volume, symptoms (tenderness and itching), and signs (color and induration) of hypertrophic (10 patients) or keloid scars (22 patients) were measured at baseline at 16 weeks following use of either the silicone gel cushion or silicone gel sheeting, as determined by random assignment. RESULTS: Both the silicone gel cushion and the silicone gel sheeting treatments were effective in decreasing scar volume, 53.0% and 36.3%, respectively. The percentages of keloids and hypertrophic scars benefiting from the silicone cushion and the silicone sheeting were similar with respect to reduction in tenderness (36.3% vs 33.3%), itching (45.5% vs 33.3%), and redness (0.1% vs 0.1%), and in the degree of softening (45.5 vs 25.0%). CONCLUSIONS: Both the silicone gel cushion and the silicone gel sheeting treatments were effective in the treatment of keloids and hypertrophic scars, although no statistically significant differences were found between the two treatment modalities.

Adult↗
PubMed1994

The capsule quality of saline-filled smooth silicone, textured silicone, and polyurethane implants in rabbits: a long-term study.

Recently, there have been many new designs in both the surface texture and chemical composition of breast implants that claim reduced constrictive capsular formation. The purpose of this study was to utilize a quantitative method to determine the firmness of capsules formed around saline-filled smooth silicone, textured silicone, and polyurethane implants in an experimental rabbit model 1 year after implantation. Our objective was to analyze the histologic, biologic, and biochemical content of the respective capsules to account for any differences in physical behavior. Forty-five smooth silicone, textured silicone, and polyurethane implants were placed in one of three positions beneath the panniculus carnosus muscle of New Zealand White rabbits. After 1 year, all capsules were palpated and classified according to firmness. Intracapsular static and dynamic pressure measurements were obtained by placing a pressure monitor (Stryker) in an injector port attached to the individual implants. Capsular firmness was significantly greater in the textured silicone implants than in the smooth silicone or polyurethane implants after 1 year. The dynamic qualities of the periprosthetic soft tissues were measured while saline was injected into the implants. The capsules around the textured silicone implants generated significantly higher pressures than the smooth silicone or polyurethane counterparts. The capsules around the polyurethane implants were the softest and most compliant in all categories. Histologically, there is a significant inflammatory response surrounding the textured silicone implants that does not exist in the capsules around the smooth silicone implants. The capsules around the polyurethane implants have the least fibrous tissue deposition. There is a decrease in the proportion of type III collagen in the capsules around the textured silicone implants versus smooth silicone or polyurethane implants. The in vitro contraction patterns of the fibroblast-populated collagen lattices do not reveal the contraction differences observed in vivo in rabbits. However, there are many components that determine contractility. This area deserves further investigation.

Animals↗
PubMed1994

MR detection of leakage from silicone breast implants: value of a silicone-selective pulse sequence.

OBJECTIVE: The purpose of this study was to determine the value of MR imaging with a silicone-selective pulse sequence for detecting leakage from silicone breast implants. SUBJECTS AND METHODS: Women with silicone breast implants were referred for this study on the basis of clinical or imaging findings suggestive of implant rupture. Twenty-eight patients with 38 implants were examined with silicone-selective MR imaging and also underwent surgical removal of the studied implant. All but four also had mammography before MR imaging. Results of silicone-selective MR imaging for the detection of silicone leakage were compared with mammographic and surgical findings. Surgical proof was considered the gold standard. RESULTS: Silicone-selective MR imaging showed an apparently intact implant in 21 cases; 20 of these were found to be intact at surgery. Silicone-selective MR imaging showed evidence of leakage in 17 implants, all of which showed leakage at surgery. The sensitivity for detection of leakage was 94%; the specificity was 100%. The findings of silicone-selective MR imaging and mammography were in agreement in 30 of 34 cases in which both studies were performed. In the four cases of disagreement, surgical findings agreed with MR findings in three and with mammographic findings in one. When the findings of mammography and silicone-selective MR imaging were combined, the correct status (leakage or no leakage) of all implants examined was determinable. CONCLUSION: Silicone-selective MR imaging is highly effective for detecting leakage from silicone breast implants. Accuracy is improved when mammographic and MR findings are considered together.

Adult↗
PubMed1998

[Cataract operation after silicone oil surgery. Oil drop adhesion to silicone lenses].

PURPOSE: To investigate the phenomenon of oil droplet formation on silicone IOLs with regard to visual acuity, intraocular pressure (i.o.p.), and clinical findings. PATIENTS AND METHODS: Retrospective study (january 1995 to December 1996) on 78 patients who underwent cataract surgery after previous complex silicone oil surgery for PVR-complicated rhegmatogenous retinal detachments (64) or proliferative diabetic retinopathy (14). Follow-up after cataract surgery 15.5 (7.55) months. PMMA IOLs were used in 50 and silicone IOLs in 19 cases. Nine patients did not receive an intraocular lens. The groups were divided up further with regard to secondary YAG capsulotomies and oil explanations. Before cataract operation, one or two (1, 23) complex vitreoretinal operations were performed with case-dependent additional retinal laser coagulations. For statistical analysis the two-sided t-test and/or Welch's test were applied. RESULTS: The preoperative mean visual acuity (VA) was significantly better (P < 0.0001) in the group treated with PMMA IOLs than in the one without IOL (VA with PMMA 0.093, silicion 0.075, without IOL 0.026). Significant improvement of VA after surgery was found with PMMA Implantation after YAG capsulotomy without silicone oil explantation (P = 0.0003). Visual improvement was best in PMMA IOLs after YAG capsulotomy with the remaining silicone oil (0.076), followed by the group without IOL implantation (0.063). In the groups with PMMA IOLs/YAG/oil explantation, a rise in VA of 0.06 was achieved, and in silicone IOLs/YAG/oil explantation, the rise in VA was 0.002. No statistically significant differences were found in postoperative mean VA. Preoperative intraocular pressure (i.o.p.) was lower in the PMMA group than in the group without IOL (P = 0.0447). No significant differences in the postoperative IOPs were found between groups, but in the PMMA/YAG/oil in situ group, IOP decreased significantly after surgery (P = 0.0142). Maculopathies were found in the PMMA group in 31, in the silicone group in 16, and in the group without IOL implantation in 7 cases. Optic atrophy was found in the PMMA group in 8, in the silicone group in 4, and in the group without IOL implantation in 3 cases. CONCLUSIONS: In all groups silicone oil surgery and secondary cataract operation with or without YAG capsulotomy and oil explantation achieved stable or slightly improved mean VA with significance in PMMA IOL implantation/YAG capsulotomy without oil explantation. Comparing PMMA IOLs/YAG/oil explantation and silicone/YAG/oil explantation, an advantage in the PMMA groups was found. However, because of large interindividual differences (large standard deviations) there was no statistical significance. Thus, in this series the phenomenon of silicone droplet adhesion on silicone IOLs is secondary to the influence of retinal pathologies.

Adult↗
PubMedDate not supplied

[Silicone occlusive sheeting vs silicone cushion for the treatment of hypertrophic and keloid scars. A prospective-randomized study].

BACKGROUND: Silicone gel and silicone occlusive sheeting are widely used at present for the treatment of hypertrophic and keloid scars. In recent studies the possibility was raised that static electricity generated by friction activated silicone sheeting could be the reason for this effect, and that it can, with time, cause involution of hypertrophic and keloid scars. Objective of this study was to test this hypothesis and to observe weather a continuous and also an increased negatively charged static electric field will shorten the treatment period. A silicone cushion was developed with the purpose of increasing a negative static-electric charge to accelerate the regression process. METHODS: From November 2001 to June 2002 we studied in a prospective randomized study, 72 patients with hypertrophic an keloid scars. The trial extended over a 8-month period. 37 patients underwent silicone occlusive sheeting, the remaining 35 patients underwent silicone cushion (Clinicel). RESULTS: Treatment with the silicone cushions yielded 74,2% cessation of itching and burning followed by pallor and flattening of the scar, some markedly so, over a few weeks to 5 months period. Additional 25,7% had their scars resolved in up to 8 months of treatment. Four patients (11,4%) who add recalcitrant scars with little response to the use of the silicone cushion were given intralesional corticosteroid injections, in addiction to the use of the cushion, resulting in a fairly rayed resolution of these scars over a period of 2 months. Treatment with the silicone occlusive sheeting yielded 52,3% itching and burning cessation followed by pallor and flattening of the scar, some markedly so, over a few weeks to 5 months period. Additional 22,1% had their scars resolved in up to 8 months of treatment. In conclusion by comparing the results of this trial using silicone cushions for the treatment of hypertrophic and keloid scars with those obtained using silicone gel or occlusive sheeting, a much faster response was demonstrated.

Cicatrix, Hypertrophic↗
PubMed1993

Silicone controversy: a survey of women with breast cancer and silicone implants.

BACKGROUND: During the past 3 years, there has been a highly publicized debate concerning the potential medical complications of silicone breast implants. There have been no studies that have addressed the effect of this controversy on women with a history of breast cancer who have undergone breast reconstruction with silicone implants. PURPOSE: This study was undertaken to understand the concerns of such women regarding their breast reconstructions and to assess what impact the silicone implant controversy had on them. METHODS: One hundred seventy-four randomly selected women who had undergone reconstructive surgery with silicone implants subsequent to mastectomy for treatment of breast cancer were interviewed by telephone from February through May 1992. (A moratorium on use of silicone breast implants, imposed by the Food and Drug Administration, extended from January through April 1992.) These women, a subset of 359 mastectomy/reconstruction patients of one university-based plastic surgeon, had their first permanent prostheses placed between 1985 and 1990. The interview included questions designed to elicit information about women's experiences with reconstruction and reactions to the controversy. RESULTS: All study participants were aware of the controversy surrounding silicone implants. Seventy-six percent stated that breast reconstruction helped them cope with cancer, and only 16% had regrets about reconstruction. Many respondents had misconceptions about the nature of possible complications from silicone implants. Fifty-five percent were worried about the implants, yet only 13% considered having them removed as a result of the controversy. Only 27% indicated they would be completely likely to choose silicone implants again. The majority of women were unwilling to accept substantial risks of complications from implants, but there was variability in the level of risk that respondents would tolerate. CONCLUSIONS: A majority of women who have had breast reconstruction using silicone implants after treatment of breast cancer believe that implants helped them cope with the cancer. However, a sizeable proportion of such women are worried about possible medical complications that may develop as a consequence of silicone breast implants. Many would likely not choose these implants today. IMPLICATIONS: The true risks associated with silicone implants will ultimately be known. In the meantime, health care providers need to address patients' concerns about these implants. Information and guidance regarding the potential benefits and risks of breast implant devices should be provided to women with breast cancer who are considering treatment options.

Adult↗
PubMed1986

Silicon metabolism. I. Some aspects of renal silicon handling in normal man.

Renal silicon handling was investigated in 23 healthy adults using electrothermal atomic absorption techniques. The mean urinary silicon excretion was 33.1 +/- 3.85 mg/day; the mean renal silicon clearance was 88.6 +/- 7.94 ml/min; the mean fractional excretion of silicon was 86.35 +/- 8.1%, and the mean urine silicon concentration was 0.265 micrograms/ml. Using multiple correlation analysis, the urinary silicon was found to be highly significantly correlated with the urine magnesium concentration (p less than 0.001) and also with urinary sodium and urinary osmolality (p less than 0.01). 24-hour urinary silicon excretion was highly significantly correlated with fractional excretion of silicon (p less than 0.001), sodium (p less than 0.001), phosphorus (p less than 0.001), magnesium (p less than 0.001), and osmolar load. In split urine studies in 7 subjects urinary silicon was correlated highly significantly with urinary magnesium in all 7 and with urinary osmolality, urine calcium, and urine creatine concentration in 6 of 7. There was a highly significant correlation between renal silicon clearance and fractional excretion of silicon (p less than 0.0005), with magnesium excretion (p less than 0.01), and with sodium excretion. It is suggested that ion pairing of orthosilicate and magnesium may explain some of these urinary findings.

Adult↗
PubMed1996

Irreversible silicone oil adhesion to silicone intraocular lenses. A clinicopathologic analysis.

PURPOSE: To report a newly defined complication of foldable intraocular lenses (IOLs), namely silicone oil-silicone IOL interaction. This is a complication not generally seen by the implanting cataract surgeon but, rather, at a later stage in a patient's postoperative course, by a vitreoretinal surgeon. METHODS: Three clinical case histories, including two explanted silicone IOLs, were submitted for analysis. The submitted silicone lenses were photographed under water, and the nature of the silicone oil coating was documented. RESULTS: In each instance, the silicone coating was manifest as a thick coating with droplet formation on the lens surface that was tenaciously adherent and could not be dislodged by instruments or injection of viscoelastics. CONCLUSION: The use of silicone IOLs in patients with current vitreoretinal disease or those who are at high risk for future vitreoretinal disease that may require silicone oil as part of the therapy should be reconsidered. The authors recommend that information regarding the existence and significance of this complication be printed on all silicone oil and silicone IOL packages and inserts (if not as a warning, at least as an informative comment regarding the existence of this condition). This is a rare but clinically significant complication that will affect the occasional patient treated with both of these modalities.

Adult↗