PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Polyhydroxyethyl Methacrylate”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 541 records · Page 30Linked to original sources
PubMed2004

Single-piece hydrophobic acrylic intraocular lens explanted within the capsular bag: case report with clinicopathological correlation.

A 74-year-old woman had uneventful phacoemulsification with implantation of a single-piece hydrophobic acrylic intraocular lens (IOL) (SA30AL) in her left eye. Two weeks after the surgery, the patient presented for ophthalmological consultation reporting pseudophakic dysphotopsia, which she had subjectively noted since surgery. Explantation/exchange of the IOL was performed 3 months after the surgery. The IOL was strongly attached to the capsule, which was fibrotic and contracted; explantation of the capsular bag complex in toto was done. To our knowledge, this is the first case of explantation of this IOL design with clinicopathological correlation.

Aged↗
PubMed2004

Single-piece AcrySof in the newborn rabbit eye.

PURPOSE: To evaluate the behavior of the single-piece AcrySof SA30AT intraocular lens (IOL) (Alcon) in the eyes of newborn rabbits and to compare the postoperative complications in aphakic and pseudophakic eyes. SETTING: St. Erik's Eye Hospital, Stockholm, Sweden. METHODS: Clear lens extraction was performed in both eyes of 20 3-week-old rabbits. In 1 randomly selected eye in each rabbit, a single-piece acrylic IOL was implanted. Preoperatively and 1 and 2 months postoperatively, axial length and corneal diameter were measured. Corneal thickness was measured at the endpoint. The rabbits were also examined clinically; the position of the IOL and signs of secondary glaucoma were noted. At 2 months, the 19 surviving animals were killed. In 10 rabbits, the wet mass of the after-cataract was measured, and the eyes of 9 rabbits were fixed in formalin for histologic evaluation. RESULTS: One animal died soon after surgery. Three rabbits developed secondary glaucoma in the aphakic eye. No rabbit developed glaucoma in the pseudophakic eye. In the 16 animals without secondary glaucoma, there were no significant differences in corneal diameter at 1 and 2 months or in corneal thickness at the endpoint; the axial length was significantly longer in aphakic eyes at 1 month, but not at 2 months. The aphakic eyes developed more posterior synechias and the pupil size at 1 and 2 months was significantly smaller in aphakic eyes than in pseudophakic eyes. Significantly more after-cataract developed in aphakic eyes than pseudophakic eyes (eyes with secondary glaucoma included). No difference in inflammation was seen between eyes in the histologic evaluation. In 11 of 19 pseudophakic eyes, the anterior capsulorhexis was not completely on the optic. In these eyes, the optic moved partly forward into the anterior chamber. CONCLUSION: The single-piece AcrySof SA30AT IOL seems to induce less inflammation and probably inhibits secondary glaucoma. It does not retard eye growth as much as previously tested IOLs. However, it is important to keep the entire capsulorhexis margin on the optic, especially in these small eyes.

Animals↗
PubMed2004

Unusual presentation of angle-closure glaucoma treated by phacoemulsification.

We report the case of a 70-year-old woman with a history of acute primary angle-closure glaucoma (PACG) in the left eye who, 2 hours after a fundus examination and mydriasis, experienced acutely elevated intraocular pressure (IOP) up to 40 mm Hg in the presence of fully dilated pupil and a patent iridotomy. Gonioscopy revealed appositional angle closure in 3 quadrants. After medical control of the IOP, sutureless cataract surgery was performed, including clear corneal incision, phacoemulsification, and soft acrylic posterior chamber intraocular lens (IOL) implantation. Eighteen months after the operation, improvement of visual acuity, widening of anterior chamber angle, and deepening of anterior chamber depth were found. Intraocular pressures are now normal without medication, even after mydriasis. Modern cataract surgery is an effective treatment for selected patients with appositional angle closure and IOP elevation after acute PACG.

Acute Disease↗
PubMed2004

Eccentric capsulorhexis and postoperative dysphotopsia following phacoemulsification.

We report a case of troublesome visual symptoms or dysphotopsia in a 68-year-old patient after right phacoemulsification and implantation of a 3-piece AcrySof(R) MA60BM acrylic intraocular lens (IOL) (Alcon) in the capsular bag. The patient described multiple horizontal streaks in dim lighting conditions with light sources in the right temporal visual field. The anterior capsulorhexis was eccentric, leaving the nasal optic edge and site of polypropylene haptic insertion uncovered by the semi-opaque anterior capsule and the probable source of the flare images. Miotic therapy was poorly tolerated and IOL exchange declined. The case illustrates the importance of creating a central capsulorhexis smaller than the IOL optic to reduce the risk photic phenomena and edge effect with square-edged IOLs.

Aged↗
PubMed2004

Uveal and capsular biocompatibility of a single-piece, sharp-edged hydrophilic acrylic intraocular lens with collagen (Collamer): 1-year results.

PURPOSE: To analyze uveal and capsular biocompatibility 1 year following implantation of a sharp-edged, hydrophilic, collagen-containing posterior chamber intraocular lens (IOL). SETTING: Department of Ophthalmology, University of Vienna Medical School, Vienna, Austria. METHOD: In a prospective study, a Collamer CC4204BF IOL was implanted in 30 eyes of patients with senile cataract. A standardized surgical technique and postoperative regimen were applied. To assess uveal biocompatibility, cellular inflammation on the anterior IOL surface was evaluated with a specular microscope. Capsular biocompatibility was registered semiquantitatively with a biomicroscope, based on an assessment of fibrosis on the anterior and posterior capsules. Tyndall values were measured with the Kowa FC-1000 laser flare-cell meter. Decentration of the lens was also registered. RESULTS: One year after implantation, the values of flare and cell count in the anterior chamber were lower than preoperatively. Round and spindle-shaped, epithelioid, and foreign-body giant cells were not found on the anterior surface of the IOL. The capsulorhexis rim was moderately fibrosed in 56.6% of cases. Fibrosis of the capsule over the optic was also moderate in 36.6%. The central portion of the posterior capsule was devoid of fibrosis in 43.3% and mildly fibrosed in 50%. Three lenses revealed outgrowth of lens epithelial cells to the anterior surface of the IOL. A neodymium:YAG capsulotomy had to be performed in 1 case. All lenses were well centered in the capsular bag 1 year after implantation. CONCLUSIONS: The absence of inflammatory cells on the anterior surface of the IOL indicates the high uveal biocompatibility of the lens. In terms of capsular biocompatibility, the results were satisfactory.

Biocompatible Materials↗
PubMed2004

Neodymium:YAG laser posterior capsulotomy after implantation of AcrySof intraocular lenses.

PURPOSE: To report the incidence of neodymium:YAG (Nd:YAG) laser posterior capsulotomy after phacoemulsification and implantation of AcrySof (Alcon) intraocular lenses (IOLs). SETTING: Private practice, Wolfe Clinic, Marshalltown, Iowa, USA. METHODS: A retrospective diagnosis and procedure code review of 12419 consecutive cases having phacoemulsification and AcrySof IOL implantation from January 1995 through December 2002 was performed. The outcome parameter was the incidence of Nd:YAG laser posterior capsulotomies. RESULTS: An Nd:YAG laser posterior capsulotomy was performed in 763 (6.1%) of the 12419 cases. The incidence of posterior capsulotomy was approximately 1% at 1 year, increasing in linear fashion by approximately 1% to 2% per year. CONCLUSIONS: The Nd:YAG laser posterior capsulotomy rate after implantation of AcrySof IOLs was relatively low; the cumulative rate was approximately 1% to 2% new cases per year over a 7-year period, with a plateau suggested at year 6.

Humans↗
PubMed2004

Pathological evaluation of postmortem human eyes implanted with a new single-piece hydrophobic acrylic lens.

PURPOSE: To report the pathological findings in 14 human cadaver eyes implanted with a single-piece AcrySof(Alcon Laboratories) posterior chamber intraocular lens (IOL). SETTING: David J. Apple, MD Laboratories for Ophthalmic Devices Research, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Fourteen human autopsy eyes implanted with a single-piece AcrySof (SA30AL) IOL were evaluated. The eyes were sectioned at the equatorial plane, and the anterior segment containing the IOL in the capsular bag was evaluated from a posterior perspective (Miyake-Apple view) and from an anterior perspective (surgeon's view) after removal of cornea and iris. They were then processed through paraffin, sectioned, and stained with hematoxylin-eosin, periodic acid-Schiff, and Masson's trichrome and examined under light microscopy. RESULTS: All IOLs had symmetric in-the-bag fixation. Slight decentration was measured in 1 eye, which also had an anterior capsule tear. Grade 1 anterior capsule opacification was present in 9 eyes. No central posterior capsule opacification or posterior capsule folds were observed in any eye. Soemmering's ring formation was observed in 5 eyes. Zonular stretch caused by different degrees of capsular bag contraction was present in 4 eyes without decentration of the IOL. CONCLUSIONS: Analyses of pseudophakic cadaver eyes from the posterior (Miyake-Apple) view, complemented by microscopic analyses, proved useful in the evaluation of IOL-capsular bag interaction. These studies are more important in cases of newly introduced lens designs.

Anterior Eye Segment↗
PubMed2006

Correction of hyperopia by intracorneal lenses: two-year follow-up.

PURPOSE: To assess the safety and efficacy of intracorneal lenses as a surgical alternative for the correction of hyperopia. SETTING: Al-Azhar University and El Magrabi Eye Hospital, Cairo, Egypt. METHODS: Twenty-three eyes of 21 patients who had a mean hyperopia of 4.3 diopters (D) +/- 0.71 (SD) (range +2.5 to +6.0 D) received Permavision lenses (Anamed Inc.), which are made of a highly permeable hydrogel with a water content of 78% and a refractive index close to that of corneal tissue (1.376). The Moria M2 microkeratome was used to make a 160 microm corneal flap with a diameter of +/-8.5 mm. The intracorneal lens was placed beneath the flap after minimal interface irrigation. RESULTS: Clinical examination showed mild corneal edema and a myopic shift during the first week postoperatively. In 17 eyes (73.9%), the postoperative uncorrected visual acuity was similar to the preoperative best corrected visual acuity (BCVA); 1 eye (4.3%) lost 1 line of preoperative BCVA. In 5 eyes (21.7%), various degrees of lens opacification with some degree of corneal haze were seen after uneventful follow-up. Decentration of 0.5 to 1.0 mm was seen in 2 eyes (8.6%), 1 of which had the lens explanted because of significant opacification. Induced astigmatism was evident in 1 eye (-1.5 D). A total of 16 eyes (69.6%) were within +/-0.5 D of target, and 20 eyes (86.9%) were within +/-1.0 D (87%). No flap melting or extrusion of the lens was recorded in 24 months of follow-up. Night halos and glare were reported in 3 eyes; all had a lens diameter of 5.0 mm. CONCLUSIONS: Intracorneal hydrogel lenses were tolerated relatively well by stromal tissue, providing a reasonably stable and predictable way to correct moderate hyperopia. However, induced astigmatism, stromal opacification, decentration, and night halos and glare occurred in a significant number of eyes. To ensure safety, deep flap cuts are preferred and these eyes should be watched carefully to avoid decentration of the lens in the early postoperative period.

Adult↗
PubMed2006

One-year follow-up of bag-in-the-lens intraocular lens implantation in 60 eyes.

PURPOSE: To report the feasibility and clinical results of implanting a bag-in-the-lens intraocular lens (IOL) designed to prevent posterior capsule opacification after cataract surgery. SETTING: Departments of Ophthalmology, University of Antwerp, Antwerp, Belgium, and University of Munich, Munich, Germany. METHODS: This prospective study comprised 63 eyes (55 patients; 7 children, 48 adults) scheduled for cataract surgery and bag-in-the-lens IOL implantation. A posterior curvilinear capsulorhexis the same size as the anterior capsulorhexis was created for IOL insertion. After surgery, lens epithelial cell (LEC) proliferation was documented every 6 months with a minimum follow-up of 12 months. RESULTS: Sixty of 63 eyes (95%) had implantation of the bag-in-the-lens IOL. Conversion to a conventional IOL was necessary in 2 cases. In 1 eye, postoperative luxation of the IOL into the vitreous occurred as a result of an oversized anterior and posterior capsulorhexis. Three eyes had early postoperative iris incarceration in the lens groove that required surgery. No LEC proliferation on the optic occurred during a mean follow-up of 22.7 months (range 12 to 64 months); LEC proliferation was confined to the peripheral capsular bag. CONCLUSION: Lens epithelial cell proliferation was mild and confined to the periphery of the capsular bag during follow-up, and the bag-in-the-lens IOL optic remained clear.

Adolescent↗
PubMed2004

Interaction of resin-modified glass-ionomer cements with moist dentine.

OBJECTIVES: The objective of this study was to report on a novel phenomenon that occurs when resin-modified glass-ionomer cements (RMGICs) are bonded to moist human dentine. METHODS: Dentine surfaces from extracted third molars were abraded with 180-grit SiC paper. Ten teeth were prepared for each of the two RMGICs tested (Fuji II LC, GC Corp. and Photac-Fil Quick, 3M ESPE). RMGIC buildups were made according to the manufacturers' instructions. After storage at 37 degrees C, 100% humidity for 24 h, the bonded specimens were cut occlusogingivally into 0.9 x 0.9 mm beams. Dentine surfaces bonded with the two RMGICs were examined along the fractured RMGIC/dentine interfaces. Additional beams fractured within the RMGICS and at 3 mm away from the interfaces were used as controls. The fractured beams were examined using scanning electron microscopy (SEM), field emission-environmental SEM (FE-ESEM) and transmission electron microscopy (TEM). RESULTS: SEM and FE-ESEM revealed numerous solid spherical bodies along the RMGIC/dentine interfaces. By contrast, no spherical bodies could be identified within the RMGIC fractured 3 mm distant from the bonded interface. TEM and energy dispersive X-ray analyses performed on carbon-coated ultrathin sections showed that these solid spherical bodies consisted of a thin aluminum and silicon-rich periphery and an amorphous hydrocarbon core within the air voids of the original resin matrix. CONCLUSION: The spherical bodies probably represent a continuation of GI reaction and poly(HEMA) hydrogel formation that results from water diffusion from the underlying moist dentine. Their existence provides evidence for the permeation of water through RMGIC/dentine interfaces.

Aluminum↗
PubMed2003

Proposed pathogenesis for the delayed postoperative opacification of the hydroview hydrogel intraocular lens.

PURPOSE: To report the clinical, histopathologic, ultrastructural, and elemental features of 17 opacified Hydroview (Bausch and Lomb Surgical, Rochester, New York, USA) hydrogel intraocular lenses (IOL) necessitating explantation and discuss from a clinicopathologic perspective why these lenses became opacified. Interventional case series with clinicopathologic correlation. METHODS: Seventeen hydrogel lenses were explanted from 17 different patients owing to decreased visual acuity or quality of vision an average of 29 months after uneventful phacoemulsification and IOL implantation and associated with a granular-appearing opacification superficially within the optic. Lenses were examined by light microscopy, transmission electron microscopy (TEM), and energy dispersion x-ray (EDX) spectroscopy. A control IOL was included in our study. RESULTS: All explanted lenses showed positive staining for calcium by light microscopy. Transmission electron microscopy disclosed electron-dense crystalline deposits in the superficial substance of the IOL optic. Energy dispersion x-ray spectra analyses showed the presence of calcium and phosphorus mainly in the electron-dense periphery of the deposits in all of the specimens and the presence of silicon mainly in the electron-lucent center of the deposits in the majority of the specimens. No positive staining or deposits were observed on the IOL control or in the haptics. CONCLUSIONS: Our study is the first to demonstrate that the calcium deposits are associated with silicon, which was presumably derived from the silicone gasket in the Surefold (Bausch and Lomb Surgical, Rochester, New York, USA) packaging system, manufactured specifically for this IOL. Silicon may act as a nidus for calcium deposition within the lens, which is consistent with our findings. There may be other factors involved, and this important clinical problem requires further study.

Aged↗
PubMed1995

Characterizing the secondary hydration shell on hydrated myoglobin, hemoglobin, and lysozyme powders by its vitrification behavior on cooling and its calorimetric glass-->liquid transition and crystallization behavior on reheating.

For hydrated metmyoglobin, methemoglobin, and lysozyme powders, the freezable water fraction of between approximately 0.3-0.4 g water/g protein up to approximately 0.7-0.8 g water/g protein has been fully vitrified by cooling at rates up to approximately 1500 K min-1 and the influence of cooling rate characterized by x-ray diffractograms. This vitreous but freezable water fraction started to crystallize at approximately 210 K to cubic ice and at approximately 240 K to hexagonal ice. Measurements by differential scanning calorimetry have shown that this vitreous but freezable water fraction undergoes, on reheating at a rate of 30 K min-1, a glass-->liquid transition with an onset temperature of between approximately 164 and approximately 174 K, with a width of between approximately 9 and approximately 16 degrees and an increase in heat capacity of between approximately 20 and approximately 40 J K-1 (mol of freezable water)-1 but that the glass transition disappears upon crystallization of the freezable water. These calorimetric features are similar to those of water imbibed in the pores of a synthetic hydrogel but very different from those of glassy bulk water. The difference to glassy bulk water's properties is attributed to hydrophilic interaction and H-bonding of the macromolecules' segments with the freezable water fraction, which thereby becomes dynamically modified. Abrupt increase in minimal or critical cooling rate necessary for complete vitrification is observed at approximately 0.7-0.8 g water/g protein, which is attributed to an abrupt increase of water's mobility, and it is remarkably close to the threshold value of water's mobility on a hydrated protein reported by Kimmich et al. (1990, Biophys. J. 58:1183). The hydration level of approximately 0.7-0.8 g water/g protein is approximately that necessary for completing the secondary hydration shell.

Calorimetry, Differential Scanning↗
PubMed2003

Extracellular matrix proteins protect pancreatic cancer cells from death via mitochondrial and nonmitochondrial pathways.

BACKGROUND AND AIMS: Pancreatic cancer is a very aggressive malignancy. Normal cells die through apoptosis when detached from extracellular matrix (ECM), but the role of ECM in cancer cell survival is poorly understood. Here, we determined the effects of ECM proteins on death responses and underlying signaling pathways in human pancreatic cancer cells. METHODS: We measured apoptosis and necrosis, caspase activation, and mitochondrial dysfunction in MIA PaCa-2 and PANC-1 pancreatic carcinoma cells both detached and attached to ECM proteins. RESULTS: Detachment of pancreatic cancer cells from ECM did not induce classic apoptosis, as it does in normal cells, but induced necrosis and apoptosis associated with secondary necrosis. It caused a pronounced mitochondrial depolarization and release of cytochrome c and Smac/DIABLO. However, as different from normal cells, cytochrome c release did not result in downstream caspase activation. Executioner caspases were activated in detached pancreatic cancer cells independent of cytochrome c. Laminin and fibronectin, but not collagen I, markedly increased pancreatic cancer cell survival by inhibiting both mitochondrial dysfunction (leading to inhibition of necrosis) and caspase activity (leading to decreased apoptotic DNA fragmentation). CONCLUSIONS: ECM proteins greatly protect pancreatic cancer cells from death by mechanisms different from those operating in normal cells. The results suggest ECM proteins and their receptors as potential targets for treatment of pancreatic cancer.

Adenocarcinoma↗
PubMed1984

Ion-exchange derivatives of Spheron. V. Sulphate and sulpho derivatives.

Using various reactions, strongly acidic derivatives of Spheron of the sulphate and sulpho types were prepared with nominal capacities between 0.37 and 2.0 mequiv./g. They were characterized by their capacities for small ions, by their static and dynamic capacities for proteins, by elemental analysis, by their working volumes and specific internal surface areas. The differences between the nominal capacities calculated theoretically from the sulphur contents and the measured values are discussed, as are the relationships between the nominal capacities for small ions and the static and dynamic capacities for proteins. The chromatographic properties of the cation exchangers are illustrated by the separation of an artificial mixture of proteins (serum albumin, chymotrypsinogen and lysozyme) at various pH values, and of a natural mixture of egg-white proteins. The separation of active enzymes is also reported. Sulphobutyl-Spheron was tested also as a catalyst for the esterification of alcohols.

Animals↗
PubMed1998

Dental extractions after radiation therapy in the head and neck area and hard tissue replacement (HTR) therapy: a preliminary study.

STATEMENT OF PROBLEM: Dental extractions in patients who had radiation therapy for cancer in the head and neck region carry with them the risks of delayed healing, prolonged alveolar bone exposure, infection, and osteoradionecrosis. Among the precautions to minimize these risks are antibiotic coverage, limited extractions at any one time, soft tissue closure, and hyperbaric oxygen treatment. Rapid epithelization and minimal bone exposure are essential after extractions in irradiated patients. PURPOSE: This study examined the effects of hard tissue replacement on head and neck cancer patients who were treated with radiation therapy. MATERIAL AND METHODS: In a series of eight patients who had radiation doses from 4000 cGy to 7440 cGy in the head and neck area and who had 44 teeth extracted, hard tissue replacement material mixed with tetracycline powder was placed in the extraction sites. RESULTS: Of the 44 teeth extracted, 19 mandibular molars and premolars were in the direct field of radiation in seven patients. One patient also had 6 mandibular anterior teeth and 12 maxillary teeth extracted that received minimal radiation exposure. One patient had 6 mandibular anterior teeth extracted that were not in the area of direct exposure. One patient had a mandibular first molar extracted in an area that received minimal radiation exposure. Clinically, complete epithelization occurred in all patients. No infections developed. Radiographically no bone dissolution could be identified in the extraction area(s). The follow-up times ranged from 7 months to 18 months when the patients were seen last. CONCLUSION: The hard tissue replacement particles appears to provide a matrix for fibrous connective tissue formation.

Anti-Bacterial Agents↗
PubMed1984

Ultrastructural studies of attachment site formation in aortic smooth muscle cells cultured on collagen-hydroxyethylmethacrylate hydrogels.

Hydroxyethylmethacrylate (HEMA) hydrogels have a peculiar crater-like topography which renders them ideal for studying cell-to-substrate contact formation. The hydrogel is quite suitable for such studies since it is transparent, which allows for light microscopic observations, it is not toxic, and it will support cell growth only when an additional protein component such as collagen is integrated into its surface. Cultured rabbit aortic smooth muscle cells (SMC) were grown on collagen-HEMA hydrogels, and the ultrastructure of developing cell attachment sites was studied. By 3 hr after cell seeding, both the rounded and the spreading SMC appeared anchored to the hydrogel via extracellular connective tissue-like material. The fully formed attachment site present at 5-8 days was characterized by large bundles of intracellular myofilaments inserting onto areas of increased electron density along the plasmalemmal membrane; large amounts of extracellular connective tissue-like material also appeared attached to the areas of increased electron density. Fully formed cell substratum attachment sites were not observed when either elastin-HEMA hydrogels or hydrogels polymerized in the absence of protein were employed.

Actin Cytoskeleton↗