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PubMed1985

Identification of noncollagenous components of calf lens capsule: evaluation of their adhesion-promoting activity.

Extraction of calf anterior and posterior lens capsules with 5 M guanidine HCI resulted in the solubilization of protein (12% of total) with a noncollagenous amino acid composition leaving behind the collagen matrix. Polyacrylamide gel electrophoresis of the solubilized material revealed a number of components, all of which were susceptible to trypsin but resistant to collagenase digestion. Fractionation of the extracted proteins by Sepharose CL-6B filtration as well as by affinity chromatography was undertaken, and laminin, fibronectin, entactin, and beta-crystallin were identified by electrophoresis and solid-phase radioimmunoassays in both anterior and posterior capsules. An entactin (Mr = 150,000), which constituted the most prominent component on electrophoresis, was purified after Sepharose CL-6B filtration by a two-step lectin affinity chromatography procedure, which was based on the failure of this protein to bind to Bandeiraea simplicifolia I but its positive reactivity with wheat germ lectin. Neither the mixture of proteins extracted from lens capsules by guanidine nor fractions prepared therefrom were able to enhance lens epithelial cell attachment to type I or type IV collagen-coated surfaces or to guanidine-prepared lens capsules; adhesion-stimulating activity could not be demonstrated even when cycloheximide-treated cells were employed. Furthermore, the cells were observed to attach as effectively to guanidine-extracted as to native capsules. These observations indicate that noncollagenous proteins are not essential for the in vitro attachment of epithelial cells to lens capsule; it appears that the collagen component itself provides an optimal surface for cell-basement membrane interaction.

Animals↗
PubMed1986

Reactivity of enprostil stereoisomers in soft elastic gelatin capsules.

Enprostil (methyl 7-[(1R*,2R*,3R*)-3-hydroxy-2-[(E)-(3R*)-3-hydroxy-4-phenoxy-1-butenyl]- 5-oxocyclopentyl]-4,5-heptadienoate), a gastric acid secretion inhibitor and potent anti-ulcer drug, is formulated as a propylene carbonate solution which is filled into soft elastic gelatin capsules. The drug molecule features two unresolved asymmetric carbon atoms, and synthesis yields an equimolar mixture of four different optical isomers (two diastereomeric pairs of enantiomers). The objective of this study was to establish the degree to which enprostil does or does not degrade stereoselectively in the soft elastic gelatin capsule formulation. Accordingly, we developed an HPLC method capable of resolving enprostil diastereoisomers and applied the method to determining reaction rates of enprostil in soft elastic gelatin capsules maintained at 40 degrees C. The study included three soft elastic gelatin capsule lots: the first two contained an equimolar mixture of all four enprostil enantiomers; and the third contained an equimolar mixture of two individual diastereoisomers of known optical purity. Comparing enprostil degradation rates in the three capsule lots showed that reactivity ratios in all cases were (within the limits of experimental uncertainty) equal to unity. This observation conclusively excludes the possibility of significant enantioselectivity for enprostil degradation in the soft elastic gelatin capsule formulation. We also report kinetic equations for the general case of relating stereospecific reactivity ratios to drug product shelf life when drug concentrations are monitored with nonstereoselective analytical techniques.

Capsules↗
PubMed1994

Ultrastructure and glycoconjugate histochemistry of the lens capsule during lens regeneration from the iris in the Newt.

The lens capsule of the regenerating lens develops from the basal lamina of the iris epithelium. As the lens differentiates and grows in size, the lens capsule increases in thickness by the formation of successive layers of basal laminar material resulting in a structure composed of increasing numbers of parallel lamellae. This initial arrangement may be lost and a more homogeneous composition of fine granules and filaments may characterize some parts of the capsule in older lenses. The developing lens capsule stains with the PAS and PAPD methods but not with the PAPS, AB and HID methods. Therefore, it appears to contain only neutral, non-acidic glycoconjugates (probably glycoproteins) which may contain fucose, galactose or mannose. This conclusion is supported by the incorporation of 3H-fucose into the developing lens capsule of regenerating lenses beginning at a stage with initial lens fiber formation. Except for the apparent absence of acidic glycoconjugates in the regenerating lens capsule, these events are similar to those described for developing lenses in chick and mammalian embryos. The differentiation of lens fibers by elongation, loss of organelles and accumulation of fine, electron-dense particles in the cytoplasm also parallels embryonic, lens fiber differentiation.

Animals↗
PubMed1989

Lens-capsule material of human and animal origin, studied by SEM.

Lens-capsule material from healthy and cataractous human lenses and from rabbits was collected with specially designed forceps. Subsequently the capsule fragments were fastened, after short pre-fixation, onto a rubber substrate with small stainless steel tacks, to prevent rolling-up of the fragments during the fixation and drying procedure for the SEM. Finally the capsule fragments were studied by SEM. Marked morphological changes, e.g., irregular swelling (like blebs) of the nuclei, formation of deep grooves at the cell borders and complete loss of epithelial cells, were found in the lens capsules obtained from certain cataractous lenses. Differences in capsule thickness were found in pathological capsule material. The imprints (attachment-lines) of the lens-fibres on the epithelial cells were often difficult to visualize.

Animals↗
PubMed1992

Growth of human acoustic neuromas, neurofibromas and schwannomas in the subrenal capsule and sciatic nerve of the nude mouse.

To develop a reproducible in vivo model for the growth of human acoustic neuromas and neurofibromas, we implanted tumor specimens (6 acoustic neuromas; 4 neurofibromas; 3 schwannomas arising in skin and soft tissues) from 13 different patients into the subrenal capsules of 67 nude mice and sciatic nerves of 64 nude mide. The animals were anesthetized and the tumors were microscopically implanted. Serial tumor volumes were determined at intervals up to 2 months by reopening the incision and directly measuring the tumor size with a micrometer. The percentages of acoustic neuromas that survived or grew were 57.1% in the subrenal capsule and 88.9% in the sciatic nerves; the percentages of neurofibromas that survived and grew were 50% in the subrenal capsule and 70% in the sciatic nerves; and the percentages of schwannomas that survived and grew were 57.1% in the subrenal capsule and 94.1% in the sciatic nerve. Tumors in the sciatic nerve also survived and grew for a longer period than those in the subrenal capsules. Tumor enlargement and stability correlated with neovascularity. At 1 or 2 months after engraftment, the tumors showed histologic appearances similar to the original tumors and immunohistochemical analysis of cryostat sections demonstrated staining of the tumors, but not the host mouse tissues for human beta 2-microglobulin, a species-specific marker. Furthermore, analysis of genomic DNA from implanted tumors revealed its human origin. We conclude that human acoustic neuromas, neurofibromas and schwannomas are readily grown in two sites in nude mice and that they retain their morphologic features and genomic identities. These tumors grow better and more consistently in the sciatic nerve than in the subrenal capsule. These are useful model systems for studying tumor growth and cellular modulation.

Animals↗
PubMed1996

Collagen synthesis in lens epithelial cells on capsules containing intraocular lens implants in rabbits: immunolocalization of prolyl 4-hydroxylase.

BACKGROUND: We evaluated ultrastructurally the presence and distribution of lens epithelial cells and extracellular matrix on the posterior capsule after implantation of a silicone or a polymethyl-methacrylate (PMMA) intraocular lens (IOL) in rabbits. The immunolocalization of prolyl 4-hydroxylase, an enzyme involved in procollagen synthesis, was also examined in such cells. METHODS: Anesthetized adult albino rabbits (n = 12) underwent phacoemulsification and aspiration (PEA) of the crystalline lens and implantation of a silicone or a PMMA IOL into the capsular bag of one eye. They were killed by an intravenous overdose of pentobarbital sodium. The lens capsules were processed for transmission electron microscopy and for immunohistochemical detection of the beta-subunit of prolyl 4-hydroxylase. RESULTS: Ultrastructurally, lens epithelial cells on the posterior capsule evidenced an accumulation of collagenous extracellular matrix. Prolyl 4-hydroxylase immunoreactivity was detected in the cytoplasm of cells distributed on the capsules. CONCLUSION: Lens epithelial cells are involved in the production of collagenous matrix on lens capsules after PEA and implantation of IOL, resulting in a fibrotic process of the lens capsule.

Animals↗
PubMed1985

Growth and differentiation of human keratinocytes cultured on eye lens capsules.

The efficiency of the outgrowth of human epidermal and hair-follicle-sheath keratinocytes was studied using three different growth substrates: plastic, type-I collagen and bovine eye lens capsules (the Epicult system). It was shown that the eye lens capsule is the best substrate, since a higher percentage of cultures showed outgrowth, and the outgrowth of epidermal keratinocytes was much more rapid. This effect is related to the faster migration (not proliferation) of cells grown on lens capsules as compared to the two other substrates. The view that lens capsules can replace the basement membrane present in vivo was supported by the finding that two basement-membrane components, i.e., laminin and fibronectin, are present on lens capsules. It was shown that, in cultures grown on lens capsules, bullous-pemphigoid antigen is restricted to the basal layer, indicating that the differentiation of these cells is comparable to that of keratinocytes grown on irradiated, non-viable pig dermis.

Animals↗
PubMed1989

Early morphogenesis of the canine lens capsule, tunica vasculosa lentis posterior, and anterior vitreous body. A transmission electron microscopic study.

This study provides transmission electron microscopic observations on the early morphogenesis (from days 25-35 post coitum) of the canine posterior lens capsule, the tunica vasculosa lentis (TVL) posterior and the anterior part of the vitreous body. The presence of an anlage of the posterior lens capsule as early as day 25, recently described histologically, was confirmed by this study. In the period from day 25 to day 35, the polar part of the posterior lens capsule develops 2-29 continuous and parallel lamellae, matching 50 nm and 1.74 microns, respectively. At these early stages, the TVL consists of capillaries that are simple endothelial tubes. From day 28 onward, these can be classified as A-1-alpha capillaries according to the classification of Bennett et al. [3]. In direct proximity to the lens capsule, the vitreous body contains fibrillar material with a morphological appearance similar to that of the lens capsule. This material probably derives from both the capillary endothelial cells' basal lamina and the lens capsule. Only few cellular components were observed in the anterior vitreous body. The development of the described structures is grossly in accordance with that observed in other mammalian species. The observations presented serve as a reference for studies on the pathogenesis of persistent hyperplastic tunica vasculosa lentis/persistent hyperplastic primary vitreous (PHTVL/PHPV), which is an important cause of leucocoria in children and in some dog breeds.

Animals↗
PubMed1995

Conditioned reinforcing effects of capsules associated with high versus low monetary payoff.

The ability of a placebo drug capsule to serve as a conditioned reinforcer as a function of being paired with money reinforcement was evaluated. Volunteers were administered two differently colored capsules that presumably contained two different drugs. Although the volunteers were told they might contain a stimulant, sedative, or placebo, both capsules contained only a placebo. During sessions, volunteers participated in performance tasks. The tasks were programmed so that following one capsule, the amount of money obtained contingent upon responding was greater (high frequency of reinforcement) than following the other capsule (low frequency of reinforcement). During experiment 1, participants were exposed twice each to the two reinforcement conditions (sampling). During these choice sessions, 9 of 12 participants chose the capsule associated with the high frequency of reinforcement 2 or 3 times. Experiment 2 was designed to explore further whether the differential mood effects observed during sampling sessions could be conditioned. Although this could not be demonstrated, the self-administration results demonstrating the control of choice behavior even in the absence of pharmacological effects suggest that drugs may function as conditioned reinforcers. This finding has implications for broadening our understanding of the determinants of initiation and continued drug use.

Adult↗
PubMed2005

The usefulness of fractional anisotropy maps in localization of lacunar infarctions in striatum, internal capsule and thalamus.

We aimed in this study to assess the clinical usefulness of fractional anisotropy (FA) maps in the evaluation of lacunar infarctions in striatum, internal capsule and thalamus. We retrospectively reviewed 28 patients (18 men, 10 women; mean age 63 years) who had acute lacunar infarction in striatum, internal capsule and thalamus on diffusion weighted MR imaging (DWI). Fractional anisotropy (FA) maps were generated in addition to conventional T2 weighted images (T2WI) and trace maps of DWI. Two radiologists reviewed the location of infarcts in combination with and without FA maps. Exact location of infarction was determined by FA maps, i.e. on the white band of internal capsule or outside the internal capsule. Accuracy and inter-observer agreement on determination of the location of infarction was evaluated. Accuracy of infarct localization by T2WI-DWI only was varied from 72 to 91% according to the observers. Inter-observer agreement value was moderate (Kappa=0.446), when images were interpreted by T2WI-DWI only. Clinical manifestation of each lesions were varied, but sensory motor stroke was mainly observed in thalamic lesion (50%), while pure motor hemiparesis was predominant in the case of infarct involving internal capsule, corona radiata (91%) and basal ganglia (83%). The FA map is useful in the evaluation of lacunar lesions in striatum, internal capsule and thalamus. Clinical presentation varies according to the exact location of lacunar infarctions, and more accurate diagnosis can be made by FA maps as well as conventional T2-weighted image and DWI.

Acute Disease↗
PubMed2004

Topical exposure of mitomycin C reduces opacification of the residual anterior lens capsule and lenticular regeneration after vitrectomy and lensectomy in rabbits.

PURPOSE: To examine the effect of topical administration of mitomycin C (MMC) on the opacification of residual anterior lens capsule in a vitrectomized/lensectomized eye. METHODS: Adult Japanese albino rabbits ( n=8) received two-port vitrectomy and lensectomy with or without topical administration of MMC (0.4 mg/ml) to the residual anterior lens capsule in one eye under both general and topical anesthesia. Four eyes after vitrectomy and lensectomy were exposed to MMC for 1 min and washed out with balanced salt solution. After 1 month, the anterior segment of each globe was observed with EAS-1000 in vivo under general anesthesia and then the enucleated globes were observed through the Miyake view. Histological examination was performed. RESULTS: During healing intervals in eyes without MMC exposure, regenerated lens structure of Soemmering's ring or fibrous tissue was formed in peripheral or central areas of the residual capsule, respectively. Both the anterior lens capsule opacification and lens fiber regeneration were statistically significantly reduced by MMC topical exposure. CONCLUSION: Lens epithelial cells produce regenerated lenticular structure and fibrous tissue on the residual capsule following vitrectomy and lensectomy in rabbits. Exposure of the residual anterior capsule to MMC may be effective in reducing both its opacification and lens fiber regeneration after vitrectomy/lensectomy.

Administration, Topical↗
PubMed2000

Immunolocalization of TGF-beta1, -beta2, and -beta3, and TGF-beta receptors in human lens capsules with lens implants.

PURPOSE: To establish the alteration in expression pattern of transforming growth factor (TGF)-betas and their receptors during repair of lens capsules after cataract surgery, we immunohistochemically located TGF-beta isoforms and their receptors in human lens capsules before and after cataract surgery. METHODS: Ten post-cataract surgery capsular specimens were obtained during vitrectomy. Three sections of the anterior capsules were obtained during cataract surgery. A whole lens capsular bag immediately after lens extraction was obtained during vitrectomy. Cryosections of these specimens were processed for immunohistochemical analysis for TGF-beta1, TGF-beta2, TGF-beta3, TGF-beta receptor type I (TbetaR-I), type II (TbetaR-II) and type III (TbetaR-III), and were observed under light micros-copy. RESULTS: Lens epithelial cells (LECs) lining the inner surface of the anterior capsules exhibited immunoreactivity for TGF-beta2 and TbetaR-II. Immunoreactivity for TGF-beta1, -beta3, TbetaR-I and TbetaR-III was negative. In the whole capsular bag specimen, equatorial LECs were positive for TGF-beta1 and -beta2, but not for -beta3. In post-cataract surgery specimens, antibodies for each TGF-beta isoform labelled either the LECs or ECM accumulated on the capsules. Post-surgical LECs expressed TbetaR-I and TbetaR-II, and had also TbetaR-III in seven of the nine specimens examined. CONCLUSION: Expression pattern of TGF-beta s in quiescent LECs showed regional heterogeneity. Anterior LECs exhibited TGF-beta2 immunoreactivity, while equatorial LECs were positive for TGF-beta1 and -beta2. Quiescent LECs expressed TbetaR-II. LECs proliferating around IOLs expressed proteins of each TGF-beta isoform and each TbetaR. TGF-beta s were also localized in the ECM on capsules undergoing repair. TGF-beta3, TbetaR-I and TbetaR-III are up-regulated in LECs after cataract surgery.

Adult↗
PubMed1996

Sialic acids of both the capsule and the sialylated lipooligosaccharide of Neisseria meningitis serogroup B are prerequisites for virulence of meningococci in the infant rat.

We investigated the contribution of the polysialic acid capsule and of terminal lipooligosaccharide (LOS) sialylation to the pathogenicity of Neisseria meningitidis in vivo using a set of defined isogenic mutants of the N. meningitidis strain B 1940 deficient in either capsule synthesis or LOS sialylation. Furthermore a spontaneous capsule-deficient variant was investigated, which was capable of switching on the capsule synthesis at a frequency of 3 x 10(-3) in vitro. Infection of infant rats with the wild-type strain revealed a high potential to cause bacteremia. This potential was attenuated in the capsule-phase variable mutant (LOS sialylation+). However, using a mutant irreversibly deficient in capsule synthesis, but expressing a sialylated LOS, bacteremia could only be achieved using 10(6) times higher numbers of bacteria when compared to the wild-type. The unencapsulated bacteria were located extracellularly upon examination of blood smears, suggesting that defense mechanisms, i.e. phagocytosis, directed against unencapsulated meningococci were exhausted using very high infecting doses. Interestingly, when infant rats were infected with encapsulated meningococci which were unable to sialylate the LOS, bacteremia could never be achieved, even with an infective dose as high as 10(8) colony forming units (CFU). Despite the presence of capsular polysaccharide this mutant was phagocytosed by peritoneal phagocytes, as was the unencapsulated, LOS-sialylated mutant, suggesting that the inability to cause bacteremia was due to a higher susceptibility to the action of the complement system, which is virtually unsaturable. We conclude that in the infant rat model of meningococcal infection both forms of sialic acid on the bacterial cell surface are indispensable for systemic survival.

Animals↗
PubMed1993

Loading and deformation of the cat posterior knee joint capsule in axial and extension rotations.

Deformation and loading of the knee posterior joint capsule were studied in the cat, in extension rotations and in axial external (ER) and internal (IR) rotations at full extension. Loads were measured in the ligament along the upper edge of the capsule, using mechanically sensitive neurons that were calibrated as load cells. Strains were measured across the surface of the capsule, by tracking a set of markers attached to its surface. External rotations produced small loads in the cable: with applied moments of up to 0.25 Nm, cable tensions were less than 0.8 mPa. The cable was not loaded by internal rotations. Axial rotations produced predominantly shear strains in the capsule. Extension produced small loads in the ligament and the predominant capsule strain was tensile along the axis of the femur. These results show that the posterior capsule has a small role in resisting extension, a minimal role in providing axial stability in ER, and no such role in IR.

Animals↗
PubMed1989

The molecular basis of pathogenicity in Haemophilus influenzae: comparative virulence of genetically-related capsular transformants and correlation with changes at the capsulation locus cap.

Serotype b strains of Haemophilus influenzae are strikingly more highly associated with episodes of invasive, life-threatening infection in young children than are strains of other serotypes, but the role that the capsule itself plays in determining this virulence has not been dissected away from that of possibly linked virulence determinants such as lipopolysaccharide (LPS). Using DNA from clinical isolates of all six serotypes (a-f) and a genetically-defined capsule-deficient recipient strain Rb-: 02, we constructed a series of capsular transformants otherwise identical with respect to outer-membrane protein and LPS subtype, biotype, and electrotype. Cloned DNA was also used to create type a and b transformants isogenic outside the capsulation locus to provide the most rigorous test to determine whether capsule alone modulates pathogenicity. Capsular transformants showed the same spectrum of virulence in an infant rat bacteremia/meningitis assay as wild-type strains, thus implicating the capsule polysaccharide as an independent determinant of virulence. Experiments in intact and splenectomised rats identified a critical role for type b capsule in enabling organisms to evade splenic clearance.

Animals↗
PubMed2006

Capsule endoscopy in 2005: facts and perspectives.

Capsule endoscopy has recently been introduced to explore endoscopically the whole small intestine, fulfilling a gap between examinations of the upper and lower gastrointestinal tract. The technique consists of a miniaturized endoscope, embedded in a swallowable capsule that is propulsed by peristalsis and achieves the journey to the right colon in five to eight hours. Images captured by the capsule are recorded on a hard drive worn in a belt by the patient. The main indication for capsule examination is the examination of the small bowel to find a bleeding lesion in patients with obscure bleeding. Several studies have shown that the diagnostic yield of capsule endoscopy is superior to that of push enteroscopy in this indication. Other possible indications are patients with suspected intestinal location of Crohn's disease, familial adenomatous polyposis, complicated coeliac disease and lesions due NSAIDs. The review contains information on the technical aspects of capsule endoscopy and discusses the indications. Issues of safety and tolerance are also discussed.

Capsules↗
PubMed2004

Polyelectrolyte multilayer capsules as vehicles with tunable permeability.

This review is devoted to a novel type of polymer micro- and nanocapsules. The shell of the capsule is fabricated by alternate adsorption of oppositely charged polyelectrolytes (PEs) onto the surface of colloidal particles. Cores of different nature (organic or inorganic) with size varied from 0.1 to 10 mum can be used for templating such PE capsules. The shell thickness can be tuned in nanometer range by assembling of defined number of PE layers. The permeability of capsules depends on the pH, ionic strength, solvent, polymer composition, and shell thickness; it can be controlled and varied over wide range of substances regarding their molecular weight and charge. Including functional polymers into capsule wall, such as weak PEs or thermosensitive polymers, makes the capsule permeability sensitive to correspondent external stimuli. Permeability of the capsules is of essential interest in diverse areas related to exploitation of systems with controlled and sustained release properties. The envisaged applications of such capsules/vesicles cover biotechnology, medicine, catalysis, food industry, etc.

Adsorption↗
PubMed2005

Preparation and characterization of NaCS-CMC/PDMDAAC capsules.

A novel capsule system composed of sodium cellulose sulfate (NaCS), carboxymethyl cellulose (CMC) and poly[dimethyl(diallyl)ammonium chloride] (PDMDAAC) was prepared for improving the properties of NaCS/PDMDAAC capsules. The process parameters, such as CMC concentration (0, 2, 4, 6 and 8 g/L), NaCS concentration (20, 25, 30, 35 and 40 g/L), PDMDAAC concentration (20, 30, 40, 50, 60, 70 and 80 g/L), reaction time and temperature were investigated to understand their effects on the diameter, membrane thickness and mechanical strength of capsules. The optimum operation conditions for preparing NaCS-CMC/PDMDAAC capsules were determined as 6-8 g/L CMC, 35-40 g/L NaCS, 60 g/L PDMDAAC and polymerization for 30-40 min. Diffusion of substances with low molecular weight into capsules was investigated, and diffusion coefficients were calculated according to the developed model. The yeast of Candida krusei was chosen as representative cell to evaluate the effects of different cell loading on capsule mechanical strength. Meanwhile the encapsulated osmophilic C. krusei cells were cultured in 250 mL shaking flasks for 72 h to determine the cell leaking properties in short and long term.

Capsules↗