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At least 667 records · Page 37Linked to original sources
PubMed2001

Effect of intraocular lens haptic compressibility on the posterior lens capsule after cataract surgery.

PURPOSE: To evaluate the effect of intraocular lens (IOL) haptic compressibility on the posterior capsule after cataract surgery. SETTING: Teaching hospital, London, United Kingdom. METHODS: In this randomized prospective study, 60 patients had standardized phacoemulsification with in-the-bag placement of a poly(methyl methacrylate) (PMMA) (Storz P497UV) or hydrogel (Storz Hydroview H60M) IOL. Both IOLs had PMMA haptics of identical configuration and length. The IOL haptic compressibility was measured in air and then during incubation in saline at 37 degrees C over 1 month. Digital retroillumination imaging was performed 1, 7, 28, 90, 180, 360, and 720 days postoperatively. The presence and duration of postoperative capsule folds were recorded and correlated with the haptic compressibility measurements, lens epithelial cell (LEC) growth patterns on the posterior capsule at 6 months, and the extent of posterior capsule opacification. RESULTS: On the first postoperative day, 21 patients (88%) in the Hydroview group had posterior capsule folds that persisted in 12 patients (50%) for 2 years. Nineteen patients (68%) in the PMMA group had folds at day 1 (P =.01), with 1 patient (3%) still having folds at 1 month (P =.0002) and no patient having folds at 3 months. At 6 months, 11 patients (46%) in the Hydroview group and no patient in the PMMA group had LEC growth in the direction of the folds. The PMMA IOLs showed a greater decrease in haptic compressibility during incubation. CONCLUSIONS: Haptic compressibility should be an important consideration in IOL design. The results suggest that to avoid posterior capsule folds, the compressibility should be less than 2.5 mN.

Aged↗
PubMed2002

Changes in the area of the anterior capsule opening after intraocular lens implantation.

PURPOSE: To evaluate the reduction rate of the area of the anterior capsule opening after continuous curvilinear capsulorhexis (CCC) with 3 types of intraocular lenses (IOLs). SETTING: St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea. METHODS: Sixty-five eyes of 51 patients having phacoemulsification and IOL implantation were assigned to 1 of 3 groups based on type of IOL: 1-piece acrylic (n = 16), 3-piece acrylic (n = 26), or silicone (n = 23). The area of the anterior capsule opening was measured 1 day and 1, 2, 3, 6, and 12 months postoperatively. RESULTS: There was significant reduction in the area of the anterior capsule opening 1 day to 3 months postoperatively in all 3 groups (P <.001). There was no further reduction after 3 months in any group. The reduction in the area of the anterior capsule opening was significantly less in both acrylic IOL groups than in the silicone IOL group at 3 months (P =.040) and 12 months (P =.023); however, there was no significant difference between the 2 types of acrylic IOLs (P =.933). CONCLUSIONS: Although there was a reduction in the area of the anterior capsule opening in all patients, the amount was significantly less in the 2 acrylic IOL groups than in the silicone IOL group. This should be considered when selecting an IOL, especially for eyes at risk for capsule contraction.

Acrylates↗
PubMed2004

Anterior capsule staining for capsulorhexis in cases of white cataract: comparative clinical study.

PURPOSE: To compare the safety and efficacy of trypan blue 0.1%, gentian violet 0.001%, indocyanine green 0.5% (ICG), fluorescein 2%, and the patient's autologous blood for anterior capsule staining in cases of white cataract. SETTING: Rajendra Prasad Center for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India. METHODS: Fifty eyes of 50 patients with age-related white cataract had anterior capsule staining with trypan blue, ICG, or gentian violet under an air bubble or subcapsularly with fluorescein or autologous blood followed by phacoemulsification with foldable intraocular lens implantation. Each stain was used in 10 eyes. The ease of creating a continuous curvilinear capsulorhexis (CCC) and the complications during the surgery were noted. Postoperative examinations at 6 hours, 1 day, 1 week, and 1 month included slitlamp microscopy, uncorrected visual acuity, and best corrected visual acuity (BCVA). The staining patterns on the anterior capsule, side port, corneal tunnel, and anterior cortex were assessed intraoperatively and within 6 hours and at 1 day. The intraocular pressure (IOP) was assessed at 1 day; pachymetry, at 1 day and 1 month; and the endothelial cell count, at 1 month. RESULTS: The surgeon had best visualization during the anterior capsulorhexis with trypan blue, ICG, and gentian violet, and a complete CCC was achieved in all eyes in the 3 groups. Two eyes each in the fluorescein and autologous blood groups had extension of the CCC so that the capsulorhexis was complete but not curvilinear. Anterior capsule fibrosis was detected with trypan blue (1 eye) and ICG (2 eyes). The anterior vitreous was stained with fluorescein in 2 eyes. All eyes achieved a BCVA of 20/30 or better from 1 week postoperatively to the last follow-up. The side port and corneal tunnel were stained most intensely with gentian violet followed by trypan blue and ICG and less intensely with fluorescein and autologous blood. The IOP, pachymetry, and endothelial cell loss were comparable between the stains. CONCLUSION: Although trypan blue, ICG, gentian violet, fluorescein, and autologous blood were safely used to stain the anterior capsule for phacoemulsification in eyes with white cataract, trypan blue, ICG, and gentian violet were more effective in staining the capsule.

Anterior Eye Segment↗
PubMed2004

Unexpected posterior capsule rupture with unfolding silicone plate-haptic lenses.

PURPOSE: To evaluate the incidence, management, and long-term outcomes of unexpected posterior capsule rupture during injection of a C11UB plate-haptic silicone intraocular lens (IOL) with the Passport II system (both Bausch & Lomb Surgical). SETTING: Tertiary referral center and teaching hospital. METHODS: This retrospective analysis comprised 24 cases of posterior capsule rupture during plate-haptic silicone IOL injection. RESULTS: Over 6 months, a C11UB IOL was injected after phacoemulsification in 3446 cases, from which 24 patients were drawn. Thus, the rate of posterior capsule rupture was 0.70%. The median preoperative best corrected visual acuity was 6/48 (range 6/12 to light perception). The median best spectacle-corrected acuity at the time of discharge or the last visit was 6/9 (range 6/4 to 6/24). Twenty patients had improved acuity, 2 lost 1 Snellen line, and 2 had unchanged acuity. There were no postoperative complications in 13 patients (54%). Three patients required further surgery. Twenty-one patients were discharged after a mean of 32 weeks +/- 22 (SD); they required a mean of 5 +/- 4 visits. The remaining 3 continue to be followed because of their preoperative ocular comorbidity. CONCLUSIONS: Although no predisposing factor was identified, we believe the risk for posterior capsule rupture during IOL injection can be minimized by careful injection technique. In particular, if there is doubt about the integrity of the zonules, anterior capsule, or posterior capsule, a plate-haptic silicone IOL should not be injected. With the appropriate management, the final visual outcome was good.

Aged↗
PubMed1994

Refractive changes induced by electrocautery of the rabbit anterior lens capsule.

The pathologic basis for presbyopia is classically attributed to lenticular sclerosis or atrophy of the ciliary muscle, but recent work suggests that thickening and loss of elasticity of the anterior lens capsule play an important role. As no practical means for attenuating or reversing the aging process of lens protein has been identified, alteration of the lens capsule eventually might prove to be a desirable alternative to spectacle correction in presbyopic individuals. This paper describes changes in the refractive properties of the lens resulting from alteration of the anterior lens capsule by application of focal cautery, using both an in vitro, in situ and an in vivo rabbit model. In vitro thermal treatment (electrocautery) of the capsule significantly increased the anterior curvature of the lens by an average of +2.95 diopters. Histologic examination of the treated lenses showed thinning of the capsule in the treated areas, as well as focal vacuolar degeneration in the lens substance beneath the lesions. In vivo thermal treatment of eyes induced a significant shift toward myopia, compared with control eyes. The accommodative range increased post-treatment relative to the controls, but the effect diminished over time, stabilizing near baseline at two to three weeks after treatment. Histologic examination showed localized changes but no signs of diffuse cataract formation. We conclude that the anterior capsule may play a significant role in the refractive power and accommodative changes in the crystalline lens.(ABSTRACT TRUNCATED AT 250 WORDS)

Accommodation, Ocular↗
PubMed1993

Restoring lens capsule integrity enhances lens regeneration in New Zealand albino rabbits and cats.

In studies conducted by numerous investigators for 150 years, lenses regenerated following endocapsular lens extraction in New Zealand albino rabbits have been irregular in shape, appearing primarily doughnut-shaped as a result of lack of lens growth at the site of the anterior capsulotomy and its adhesion to the posterior capsule. In the present study, we restored the lens capsule integrity by inserting a collagen patch at the time of surgery to seal the anterior capsulotomy and to improve the shape and structure of the regenerated lenses. We then filled the capsule bag with air to prevent adhesions between the anterior and posterior capsule and maintain capsule tautness and shape. Lens regeneration was first noted as early as one to two weeks. Regenerated lens filled approximately 50% of the capsule bag at two weeks and 100% by five weeks. Subsequent growth was in the anterior-posterior direction and measured by A-scan biometry. Lens thickness increased by 0.3 mm per month. The regenerated lenses were spherical with normal cortical structure and a nuclear opacity. In conclusion, restoration of lens capsular integrity with a collagen patch following endocapsular lens extraction enhanced the shape, structure, and growth rate of the regenerated lenses. In addition, lens regeneration was shown to occur in two cats.

Air↗
PubMed1990

Biometry of the posterior lens capsule: a new method to predict pseudophakic anterior chamber depth.

The distance between the anterior corneal vertex and the posterior lens capsule was measured in 60 eyes before and three months after extracapsular cataract extraction with implantation of a posterior chamber lens. The preoperative capsule position ranged from 6.15 mm to 8.60 mm and averaged 7.64 +/- 0.47 mm (+/- SD). All posterior lens capsules had moved anteriorly following surgery. The postoperative capsule position ranged from 4.31 mm to 5.53 mm and averaged 4.93 +/- 0.29 mm. The postoperative capsule position could be predicted by the following optimized multiple linear regression equation: 2.4 + 0.011 x patient age + 0.171 x anterior chamber depth + 0.051 x axial length. The multiple correlation coefficient was 0.48. The postoperative anterior depth could be predicted with a correlation coefficient of 0.61 by subtracting both the averaged value of the clinical "laser space" and the exact central implant thickness from the estimated position of the posterior lens capsule. We suggest that this principle for predicting the postoperative anterior chamber depth may be useful for a number of lenses with different designs.

Adult↗
PubMedDate not supplied

Posterior capsule rupture by blunt ocular trauma.

A patient with posterior lens capsule rupture caused by blunt trauma and in whom the anterior capsule and the remainder of the eyeball structure was intact had phacoemulsification and aspiration of the crystalline lens with implantation of a posterior chamber intraocular lens. Further rupture of the capsule was prevented by the fibrosis, which tightened the margin of the ruptured capsule. This case shows that blunt trauma can rupture the posterior lens capsule, leaving the anterior capsule intact.

Adult↗
PubMed2001

Evaluation of the Intelisite capsule to deliver theophylline and frusemide tablets to the small intestine and colon.

The objective of the research was to establish the capability of the Intelisite capsule to deliver the probe drugs, theophylline and frusemide, in the form of split immediate release (IR) tablets, to the small intestine and colon. The two probe drugs were administered together in an open, random, three-way crossover study in eight healthy volunteers, comparing absorption following Intelisite delivery in the small bowel and colon to conventional IR dosing. Gamma scintigraphy was employed to monitor the gastrointestinal transit and activation of the Intelisite capsule. Standard pharmacokinetic parameters, and the percentage remaining in the capsules post defecation were determined. The Intelisite capsule was well tolerated in human volunteers and successfully activated on 15/16 occasions. Pharmacoscintigraphy showed internal marker release from the Intelisite capsule to be approximately 10-fold faster in the small intestine than in the colon. Theophylline and frusemide were both well absorbed following Intelisite activation in the small intestine, whereas complete colonic absorption was only observed in 1/7 subjects for theophylline, and 0/7 subjects for frusemide. The probe drugs were successfully delivered in particulate form from the Intelisite capsule in the small intestine and produced expected pharmacokinetic profiles. However drug release in the colon was incomplete and variable possibly due to: low water content, poor mixing, and a high loading dose.

Adult↗
PubMed1997

Dissolution testing of soft shell capsules-acetaminophen and nifedipine.

The problem of pelliculation of soft gelatin capsules on aging has been studied. Pelliculation frequently differs in soft shell capsules from hard shell capsules because of the larger mass of gelatin in the softshell dosage form. Two batches of nifedipine soft shell capsules are described. One batch failed in vivo testing and the other batch did not, after storage at 25 degrees C, yet both batches failed dissolution testing by the USP apparatus II method. The USP dissolution apparatus III-method, however, distinguished correctly between the batches. The study reported here was carried out with acetaminophen and was set up to establish whether the USP apparatus III testing method would be more suitable, and if so, what the most desirable dissolution medium should be. To create controlled pelliculation, samples were made with 0, 20, and 80 ppm of formaldehyde. The resulting capsules were subjected to ambient and accelerated storage and dissolution testing was carried out. It was found that the USP apparatus III method best reflected distinction between acceptable and substandard capsules.

Acetaminophen↗
PubMedDate not supplied

Encapsulation of submicrometer-sized 2-methoxyestradiol crystals into polymer multilayer capsules for biological applications.

A facile approach has been developed to encapsulate submicrometer-sized drug crystals into polymer multilayer capsules produced by sequential deposition of polymers onto the drug particle surfaces. 2-Methoxyestradiol (2-ME) is a hydrophobic metabolite of 17-beta estradiol, which has been demonstrated as a potential anticancer agent. It was selected as a model drug and was formulated into submicrometer-sized particles through fine milling followed by intense sonication in the presence of dipalmitoyl-dl-(R)-phosphatidylcholine (DPPC). The reserved positive charges on the 2-ME crystal surface by DPPC enhanced the water solubility of the particles and subsequent self-assembly of dextran sulfate (DS) and dextran (DN) multilayers through hydrogen bonding and physical adsorption. Upon the exposure of the drug capsules to ethanol, hollow DS/DN multilayer polymer shells can be formed. The encapsulation process and hollow polymer multilayer shell formation were confirmed by confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM), while the surface morphology of the formed drug capsules was investigated using scanning electron microscopy (SEM). In vitro studies show that the inhibitory effect of the formed 2-ME capsules is the same as that of the conventional formulation of 2-ME in a concentrated ethanol solution, as demonstrated by dramatic changes in cell morphology and significantly decreased viability of target cells. We also demonstrate that the change of the outermost layer of the drug capsules does not significantly influence its bioactivity. The presented strategy to encapsulate submicrometer-sized hydrophobic drug particles is expected to provide a general pathway to fabricate drug capsules for various biological applications.

2-Methoxyestradiol↗
PubMed2000

The anterior lens capsule used as support material in RPE cell-transplantation.

PURPOSE: To investigate the use of an ocular basement membrane as support material for transplanted porcine RPE cells. METHODS: Porcine RPE cells were grown on bovine corneal extracellular matrix (ECM), isolated bovine- and porcine lens capsules, and tissue culture plastic. Cell density, and cell morphology were studied by phase contrast microscopy and transmission electron microscopy. RESULTS: RPE cells grown on porcine anterior lens capsule and on ECM obtained better morphology and higher final cell density than cells grown on plastic and on bovine anterior lens capsule. It was possible to transplant the porcine anterior lens capsule to the subretinal space in pigs. Within two weeks of observation, the lens capsule was well tolerated in the subretinal space. CONCLUSION: The anterior lens capsule seems to be promising as support material for use in RPE cell-transplantation.

Animals↗
PubMed1986

Variability of steady-state digoxin kinetics during administration of tablets or capsules.

An encapsulated solution of digoxin has been repeatedly shown to have greater bioavailability than tablet forms of the drug. It is predicted that such a preparation would show reduced within- and between-patient variability in absorption, as most studies in normal subjects have shown reduced intersubject variation with the capsule. We tested inter- and intrapatient variability during 4-week periods of dosing with digoxin capsules and tablets in 28 subjects with cardiac disease. In the overall group there were no significant differences between the formulations at steady state in between-patient variability in trough serum digoxin concentrations or 24-hour urinary digoxin excretion. Within-patient variability in urinary digoxin excretion was somewhat lower for the capsules. In a subgroup of six patients who excreted significant amounts of cardioinactive bacterial metabolites (digoxin reduction products [DRP]), the mean (+/- SD) percent urinary DRP excretion was less (p less than 0.05) during capsule (20.5% +/- 15.1%) than tablet (34.4% +/- 10.9%) dosing. Within-patient variability in urinary DRP excretion was much greater after tablets than capsules. Certain subgroups of patients should benefit from the enhanced bioavailability of digoxin capsule preparations.

Absorption↗
PubMed2004

Capsule synthesis by Bacillus anthracis is required for dissemination in murine inhalation anthrax.

Bacillus anthracis, the agent of anthrax, produces a poly-D-glutamic acid capsule that has been implicated in virulence. Many strains missing pXO2 (96 kb), which harbors the capsule biosynthetic operon capBCAD, but carrying pXO1 (182 kb) that harbors the anthrax toxin genes, are attenuated in animal models. Also, noncapsulated strains are readily phagocytosed by macrophage cell lines, whereas capsulated strains are resistant to phagocytosis. We show that a strain carrying both virulence plasmids but deleted specifically for capBCAD is highly attenuated in a mouse model for inhalation anthrax. The parent strain and capsule mutant initiated germination in the lungs, but the capsule mutant did not disseminate to the spleen. A mutant harboring capBCAD but deleted for the cap regulators acpA and acpB was also significantly attenuated, in agreement with the capsule-negative phenotype during in vitro growth. Surprisingly, an acpB mutant, but not an acpA mutant, displayed an elevated LD(50) and reduced ability to disseminate, indicating that acpA and acpB are not true functional homologs and that acpB may play a larger role in virulence than originally suspected.

Animals↗
PubMed2003

A pharmacoscintigraphic evaluation of oral budesonide given as controlled-release (Entocort) capsules.

AIMS: To investigate the gastrointestinal pharmacokinetics of controlled-release (Entocort) and standard budesonide capsules. METHODS: Six Crohn's disease patients and eight healthy controls were given controlled-release capsules containing budesonide and an inert 111In label, following breakfast. In the patients, a standard capsule containing deuterium-labelled budesonide was given simultaneously. In the controls, on a separate occasion, the controlled-release capsules were given in the fasting state. Gastrointestinal transit was recorded by a gamma camera. Plasma budesonide and deuterium-labelled budesonide were used to estimate drug release, and urine cortisol was used to assess systemic effects. RESULTS: Budesonide delivery to the ileo-colonic region was significantly greater after the intake of the controlled-release capsules [69%; 95% confidence interval (CI), 54-84] than after the standard capsules (30%; 95% CI, 15-45) (P = 0.005). Fasting had little impact on uptake. The transit and pharmacokinetics of budesonide were similar in both subject groups, although systemic availability was higher in patients (21%; 95% CI, 13-33) than in controls (12%; 95% CI, 10-14) (P = 0.009). Urinary cortisol was, however, similar in both groups. CONCLUSIONS: A major fraction of budesonide is released in the ileum and throughout the colon, the intended target for the controlled-release formulation. The prandial state has little effect on budesonide uptake.

Administration, Oral↗
PubMed2000

Study on masticatory movement and its ability: efficacy of a test capsule in the evaluation of masticatory movement.

It has been shown that a test capsule originally designed as a simple and reliable aid to evaluate masticatory ability could help to identify the characteristics of chewing loops between individuals in evaluation of masticatory movement, and detect even a slight disorder in the stomatognathic system. In this study, the Sirognathograph(R) Analysing System was used to record and analyse mandibular movement with the test capsule and seven foods. In terms of total examination of the chewing rhythm, the test capsule showed a higher SX/SY ratio of chewing cycle duration (SX: variance between individuals, SY: variance between chewing loops of each person) than those of the comparative foods, excluding chewing gum. The coefficient of variation of the test capsule in the dimensions of the chewing path was lower than those of the comparative foods. Reverse and crossover patterns in chewing gum have been frequently observed in subjects with craniomandibular disorders. Subjects with a low frequency of such patterns in chewing gum tended to have a low frequency with the test capsule as well. Those with a high frequency in chewing gum tended to show such patterns with the test capsule more frequently.

Adult↗
PubMed2004

Wireless capsule endoscopy and double-balloon enteroscopy for the diagnosis of obscure gastrointestinal bleeding.

Standard endoscopic examination (upper gastrointestinal endoscopy and colonoscopy) fails to detect the cause of gastrointestinal hemorrhage in approximately 5% of patients. Before the availability of wireless capsule endoscopy and double-balloon enteroscopy, imaging modalities for the small intestine distal to the ligament of Treitz included barium contrast examination and/or enteroclysis, push, passive, or intraoperative enteroscopy, technetium 99m labeled sulfur colloid scanning, angiography, and computed tomography, although the diagnostic yield of all of these imaging modalities was low. In 2001, wireless capsule endoscopy became available for the evaluation of patients with probable small intestinal hemorrhage. Advantages of wireless capsule endoscopy include that the procedure is noninvasive, requires no sedation, and does not expose the patient to ionizing radiation. In patients with obscure gastrointestinal hemorrhage, studies have demonstrated an additional 25 to 50% diagnostic yield using wireless capsule endoscopy when compared to other diagnostic modalities. The major limitations of capsule endoscopy were its inability to obtain a biopsy, precisely localize a lesion, or perform therapeutic endoscopy. In 2001, the double-balloon enteroscope was introduced. This new endoscopic technique provides the gastroenterologist with an opportunity for further evaluation and treatment of abnormalities detected on wireless capsule endoscopy or other small intestinal imaging studies.

Capsules↗
PubMed1999

The capsule of Mycobacterium tuberculosis and its implications for pathogenicity.

Mycobacterium tuberculosis, one of the most prevalent causes of death worldwide, is a facultative intracellular parasite that invades and persists within the macrophages. Within host cells, the bacterium is surrounded by a capsule which is electron-transparent in EM sections, outside the bacterial wall and plasma membrane. Although conventional processing of samples for microscopy studies failed to demonstrate this structure around in vitro-grown bacilli, the application of new microscopy techniques to mycobacteria allows the visualization of a thick capsule in specimen from axenic cultures of mycobacteria. Gentle mechanical treatment and detergent extraction remove the outermost components of this capsule which consist primarily of polysaccharide and protein, with small amounts of lipid. Being at the interface between the bacterium and host cells, the capsule and its constituents would be expected to be involved in bacterial pathogenicity and past work supports this concept. Recent studies have identified several capsular substances potentially involved in the key steps of pathogenicity. In this respect, some of the capsular glycans have been shown to mediate the adhesion to and the penetration of bacilli into the host's cells; of related interest, secreted and/or surface-exposed enzymes and transporters probably involved in intracellular multiplication have been characterized in short-term culture filtrates of M. tuberculosis. In addition, the presence of inducible proteases and lipases has been shown. The capsule would also represent a passive barrier by impeding the diffusion of macromolecules towards the inner parts of the envelope; furthermore, secreted enzymes potentially involved in the detoxification of reactive oxygen intermediates have been identified, notably catalase/peroxidase and superoxide dismutase, which may participate to the active resistance of the bacterium to the host's microbicidal mechanisms. Finally, toxic lipids and contact-dependent lytic substances, as well as constituents that inhibit both macrophage-priming and lymphoproliferation, have been found in the capsule, thereby explaining part of the immunopathology of tuberculosis.

Bacterial Adhesion↗