Capsule Defect Research Articles

NIF Ignition Target Requirements, Margins, and Uncertainties: Status February 2010

Targets intended to produce ignition on the National Ignition Facility (NIF) are being simulated, and the simulations are used to set specifications for target fabrication. Recent design work has focused on incorporating the implications of NIF experiments that were done in fall 2009 and planning for the campaign in 2010. Near-term experiments will use Ge-doped CH, although Be and diamond are still under active consideration for 2011 and beyond. The emphasis in this paper will be on changes in the requirements over the last year, the characteristics of the 2010 CH-ablator design, and the designs for 2011 and beyond. Capsule defects of particular interest are surface perturbations on the CH ablator and composition variations in the Be shells. Complete tables of specifications are regularly updated for all of the targets. All the specifications are rolled together into an error budget indicating adequate margin for ignition with all of the designs.

Retinoid signaling in inner ear development: A “Goldilocks” phenomenon

Retinoic acid (RA) is a biologically active derivative of vitamin A that is indispensable for inner ear development. The normal function of RA is achieved only at optimal homeostatic concentrations, with an excess or deficiency in RA leading to inner ear dysmorphogenesis. We present an overview of the role of RA in the developing mammalian inner ear, discussing both how and when RA may act to critically control a program of inner ear development. Molecular mechanisms of otic teratogenicity involving two members of the fibroblast growth factor family, FGF3 and FGF10, and their downstream targets, Dlx5 and Dlx6, are examined under conditions of both RA excess and deficiency. We term the effect of too little or too much RA on FGF/Dlx signaling a Goldilocks phenomenon. We demonstrate that in each case (RA excess, RA deficiency), RA can directly affect FGF3/FGF10 signaling within the otic epithelium, leading to downregulated expression of these essential signaling molecules, which in turn, leads to diminution in Dlx5/Dlx6 expression. Non-cell autonomous affects of the otic epithelium subsequently occur, altering transforming growth factor-beta (TGFβ) expression in the neighboring periotic mesenchyme and serving as a putative explanation for RA-mediated otic capsule defects. We conclude that RA coordinates inner ear morphogenesis by controlling an FGF/Dlx signaling cascade, whose perturbation by deviations in local retinoid concentrations can lead to inner ear dysmorphogenesis.

Circular anterior lens capsule rupture caused by blunt ocular trauma

A 16 year old male experienced blunt ocular trauma causing rupture of the anterior lens capsule and mature cataract development. The trauma was due to a stone that impacted the left eye. In an otherwise clear lens, an anterior lens capsule defect formed post-trauma that progressed to a mature cataract over four months reducing distance vision from 20/125 to hand motion. The patient underwent phacoemulsification with posterior chamber intraocular lens implantation in the left eye. One year postoperatively, the vision in the left eye increased to 20/25 without correction. This is a rare case of cataract formation due to a defect in the anterior lens capsule caused by blunt ocular trauma.

Asynchrone Facettgelenks-Zyste nach Facettgelenks-Punktion: eine Falldemonstration

Lumbar synovial cysts represent a rare condition, they are believed to arise from defects of the joint capsule due to degeneration, trauma, rheumatoid arthritis or spondylosis. The symptom spectrum ranges from neural claudication to neurological deficits. We report the case of a contralateral asynchronous facet joint cyst after surgical resection and review the literature.

Modified Malyugin ring iris expansion technique in small-pupil cataract surgery with posterior capsule defect

We describe a simple technique involving modification of iris expansion with the Malyugin ring (MicroSurgical Technology) in nondilating small-pupil cataract surgery with preexisting posterior capsule defect or intraoperative posterior capsule tear. A 6-0 polyglactin suture is placed in the leading scroll of the Malyugin ring, and the end of the suture is secured at the main port incision. This prevents the iris expander from inadvertently dropping into the vitreous during intraoperative manipulation.

Paediatric cataract surgery

Bilateral congenital cataract is the most common cause of treatable childhood blindness. Nuclear cataract is usually present at birth and is non-progressive, while lamellar cataract usually develops later and is progressive. Prompt surgery has to be performed in cases with dense congenital cataract: if nystagmus has developed, the amblyopia is unfortunately irreversible. A treatment regime based on surgery within 2 months of life, combined with prompt optical correction of the aphakia and occlusion therapy with frequent follow-up, have been successful in both unilateral and bilateral cases. The surgery ought to include anterior and posterior capsulorexis in all children at the present time. Intraocular lens implantation has been safely performed below the age of 1 year and has also been successfully performed in bilateral cases. Anterior dry vitrectomy should be performed in preschool children to avoid visual axis opacification. Visual axis opacification is the most common complication found after cataract surgery in children. Secondary glaucoma is by far the most sight-threatening complication and is, unfortunately, common in the newborn so lifelong follow-up is essential in these cases.

Proposed classification of lens capsule defects

Capsule defects are common during or after intraocular surgery of various kinds. The purpose of this work is to establish a classification system of lens capsule defects to provide uniform description of these defects for ophthalmic research and IOL implantation. A retrospective study of 128 patients (156 eyes) with lens capsule injury after ocular trauma and intraocular surgery was performed. The patients were divided into two groups. Capsule defects were defined and classified according to the location, size, shape and tension of the capsule and its effect on posterior chamber IOL implantation. Lens capsule defects were classified into four types: Type I - complete capsule; Type II - incomplete capsule, but has enough area and tension to support two IOL haptics; Type III - incomplete capsule, is able to support only one IOL haptic and the other haptic needs a suture; Type IV - no capsule, both IOL haptics need suture fixation. Type I and Type II were each divided into three subtypes. Type III was divided into two subtypes. The shape of the capsule defects included fissure-like, triangle, round, irregular and fan-like. All eyes with capsule defects can be sorted into one of these types, and it is easy to guide IOL implantation according to the classification. Type II was the most common among the two groups in this study. The classification of lens capsule defects is feasible and favorable for uniform clinical description, clinical research and IOL implantation.

Preexisting posterior capsule defect progressing to white mature cataract

We present two children discovered to have a total cataract in one eye with a posterior subcapsular cataract in the other eye. Sequential photography documented rapid progression of the posterior subcapsular cataract to a preexisting posterior capsule defect and subsequently to a white, mature cataract. We propose that early intervention be considered in cases with any posterior subcapsular changes (no matter how subtle) and history of total cataract in the fellow eye, especially in any situation where loss of follow-up is likely to occur. In the event surgery is not advised, parents should be warned about possible cataract progression and the importance of regular follow-up examinations.

Implantation of foldable intraocular lens with anterior optic capture in isolated posterior capsule rupture

We would like to raise several pertinent points regarding isolated posterior capsule rupture occurrence and its management described in the article by Pushker et al.1 Isolated posterior capsule rupture is a well-recognized clinical entity. In our literature review, we came across 22 cases reported prior to the authors' case.2–9 Previous authors suggest that the absence of a formed nucleus in young patients allows contrecoup forces to be transmitted through the lens substance.3 We theorize that its occurrence in young patients following blunt trauma is due to localized pressure buckling the cornea and deforming the soft nucleus (with posterior bulging against the posterior capsule). In addition, zonular tension pulls the posterior capsule centrifugally. This combination results in a blow-out rupture of the posterior capsule. We recently managed a similar case. Two months following blunt ocular trauma, a 19-year-old man had lens aspiration with implantation of an Alcon MA60BM intraocular lens (IOL) in the capsular bag. We aspirated the lens through a superior 2.75 mm clear corneal incision using automated irrigation/aspiration with an anterior chamber maintainer (ACM). With low-flow settings and the ACM, no vitreous prolapsed and anterior vitrectomy was not required. The posterior chamber IOL was placed in the capsular bag, with no optic capture, and has remained stable with over 1 year of follow-up. Even without grossly fibrotic edges, these posterior capsular defects are relatively stable and resistant to enlargement like posterior capsulorhexis. In essence, we feel that vitreous loss should be avoided with the attendant reduction in the risk for retinal detachments and cystoid macular edema. Plain capsular bag fixation is also possible in most cases and is ideal because prolapsing the optic anteriorly brings it closer to the iris and increases the risk for iris chafing and pigment dispersion. If the defect is extremely large or the edges of the posterior capsule defect are not visualized, the posterior chamber IOL haptics should be placed in the ciliary sulcus (with posterior optic capture through an intact anterior capsulorhexis). In fact, anterior optic capture was recommended by Gimbel and DeBroff10 in cases in which the posterior capsule tear occurred during or after posterior chamber IOL insertion rather than in cases with preexisting breaks. In cases of posterior capsule tear during or after posterior chamber IOL insertion, leaving the haptics in the capsular bag, rather than trying to dial them out into the sulcus, minimizes vitreous disturbance. Finally, we would like to point out that the Alcon MA30BA has polymethyl(methacrylate) haptics not polypropylene haptics as mentioned by the authors.

Vitreous prolapse and IOL dislocation during intravitreal injection of triamcinolone acetonide

To report on procedure-related anterior segment complications during intravitreal injections. In a prospective interventional case series, 614 eyes received a total of 723 intravitreal injections of about 20 mg triamcinolone acetonide (in 0.2 ml) after paracentesis and aqueous humor drainage for various indications. In three eyes (0.49% of all eyes) a vitreous prolapse occurred during the injection. In one eye, the vitreous prolapse was combined with dislocation of the intraocular lens (IOL). All three eyes were pseudophakic, showing an posterior capsule defect, and the IOL located in the ciliary sulcus. They were treated by translimbal vitrectomy, and one eye with reposition of the IOL. No other procedure-related postoperative complications were observed during injection or follow-up (7.8+/-7.1 months). Intravitreal injections may cause a vitreous prolapse into the anterior chamber with or without IOL decentration or dislocation in predisposed eyes. Ophthalmologists should be aware of this possible complication and inform patients at risk.

Funktionelle Sehnenersatzoperationen in der Tumorchirurgie

Large defects of functional soft tissue structures, e.g., extensor mechanism, ligaments, muscles, and joint capsule, may occur in tumor surgery or revision surgery following conventional joint replacement. Reconstruction can be performed using biological grafts such as free or pedicled tendon-muscle flaps, allografts, or synthetic material. Prerequisites for synthetic material are good biologic tolerance with fibroblastic ingrowth, mechanical resistance to fatigue, and a maximum of tension force with a minimum of elongation. In this study we used a nonresorbable band of longitudinal polyester fibers with a minimal rupture level of 4000 N and an elongation rate less than 7% of its original length. The shape of the band was designed for universal use with 40 cm length and 6 cm width. Its primary indication was augmentation or complete reconstruction of the extensor mechanism of the knee joint after large extra-articular tumor resections in primary bone tumors. Furthermore, its use for hip joint capsule reconstruction in luxation, coverage of megaprostheses of the humerus, and augmentation after biological reconstruction of tendons achieved excellent results.

Analysis of the shortvein cis-regulatory region of thedecapentaplegic gene ofDrosophila melanogaster

In mammals, the Transforming Growth Factor-beta (TGF-beta) superfamily controls a variety of developmental processes. In Drosophila, by contrast, a single member of the superfamily, decapentaplegic (dpp) performs most TGF-beta developmental functions. The complexity of dpp functions is reflected in the complex cis-regulatory sequences that flank the gene. Dpp is divided into three regions: Hin, including the protein-coding exons; disk, including 3' cis-regulatory sequences; and shortvein (shv), including noncoding exons and 5' cis-regulatory sequences. We analyzed the cis-regulatory structure of the shortvein region using a nested series of rearrangement breakpoints and rescue constructs. We delimit the molecular regions responsible for three mutant phenotypes: larval lethality, wing venation defects, and head capsule defects. Multiple overlapping elements are responsible for larval lethality and wing venation defects. However, the area regulating head capsule formation is distinct, and resides 5' to these elements. We have demonstrated this by isolating and describing two novel dpp alleles, which affect only the adult head capsule.

UDP-glucose Dehydrogenase Plays Multiple Roles in the Biology of the Pathogenic Fungus Cryptococcus neoformans

Cryptococcus neoformans is a pathogenic fungus surrounded by an elaborate polysaccharide capsule that is strictly required for its virulence in humans and other mammals. Nearly half of the sugar residues in the capsule are derived from UDP-glucuronic acid or its metabolites. To examine the role of these nucleotide sugars in C. neoformans, the gene encoding UDP-glucose dehydrogenase was disrupted. Mass spectrometry analysis of nucleotide sugar pools showed that the resulting mutant lacked both UDP-glucuronic acid and its downstream product, UDP-xylose, thus confirming the effect of the knockout and indicating that an alternate pathway for UDP-glucuronic acid production was not used. The mutant was dramatically affected by the lack of specific sugar donors, demonstrating altered cell integrity, temperature sensitivity, lack of growth in an animal model of cryptococcosis, and morphological defects. Additionally, the polysaccharide capsule could not be detected on the mutant cells, although the possibility remains that abbreviated forms of capsule components are made, possibly without proper surface display. The capsule defect is largely independent of the other observed changes, as cells that are acapsular because of mutations in other genes show lack of virulence but do not exhibit alterations in cell integrity, temperature sensitivity, or cellular morphology. All of the observed alterations were reversed by correction of the gene disruption.

Investigation of various factors affecting encapsulation on the In-Cap automatic capsule-filling machine

The purpose of this study was to determine the factors that influence fill weight and weight variability of capsules produced on the In-Cap and to assess any differences in terms of capsule defects between gelatin and HPMC (Quali-V) shells. The In-Cap is an automatic tamping type capsule-filling machine and the low output of approximately 3000 capsules/hour makes it ideal for early formulation development and phase I/IIa clinical supplies manufacture. Four commonly used excipients (Avicel PH101, Avicel PH302, A-Tab, and Prosolv HD90) and a poorly flowing drug blend were encapsulated at various pin settings and powder bed heights. The average fill weight and coefficient of weight variation were determined. The percentage of defective capsules formed during encapsulation was calculated. Results of the study showed that pin setting was critical for controlling the fill weight and the weight variation. The order of pin setting with pin 1 (closer to the powder chute) set to a relatively higher position and pin 4 (before ejection) set to a lower position was found to give higher fill weights with relatively lower weight variability. The powder bed height influenced the fill weight for poorly flowing powders. The capsule machine speed did not appear to significantly influence the fill weight. The fill weight and weight variation were found to depend on the flow property of the material. A large percentage of defective capsules was obtained using HPMC shell size #00. Some of the commonly observed defects included split caps and improperly closed filled capsules. In general, appropriate selection of pin settings and bed height can reduce the weight variability seen, especially with poorly flowing high-dose formulations.

Arthroscopic posterior portal closure.

Posterior "working" portals in arthroscopic posterior stabilization could result in defects of the posterior capsule if not repaired. We describe a single portal technique used to close the posterior portal defect after arthroscopic stabilization. It is a safe and easy-to-perform technique, which could strengthen the structural integrity of the repair.

Diagnosis and management of congenital cataract with preexisting posterior capsule defect

Purpose: To establish and evaluate the diagnostic signs, intraoperative performance, and postoperative outcomes in children with congenital cataract with a preexisting posterior capsule defect (PCD). Setting: Iladevi Cataract & IOL Research Centre, Ahmedabad, India. Methods: This study evaluated 400 consecutive eyes that had congenital cataract surgery, of which 27 (20 children) had a confirmed preexisting PCD. Seven children had bilateral defects. The preoperative diagnostic signs of PCD under maximum pupil dilation included well-demarcated, thick defect margins; white dots on the posterior capsule; and white dots in the anterior vitreous that moved with the degenerated vitreous like a fish tail (fish-tail sign). Hydrodissection was not attempted. Bimanual irrigation/aspiration and 2-port anterior vitrectomy were performed. The mean follow-up was 17.9 months ± 16.96 (SD). Results: The mean age of the 16 boys and 4 girls with a PCD was 21.98 ± 33.33 months. Nineteen eyes (70.3%) had total white mature cataract. In 7 eyes (25.92%), the preexisting PCD was converted into a posterior capsulorhexis. Twenty eyes (74.07%) had an AcrySof MA30BA intraocular lens (IOL) implanted in the bag and 4 eyes (14.81%), in the sulcus. Three eyes (11.11%) were left aphakic. The visual axis remained clear in all eyes, and the IOL was well centered in 24 eyes (88.88%). Conclusion: Establishing the diagnostic signs of PCD with the eye fully dilated and carefully planning the surgery produced satisfactory technical and visual outcomes.

Chronic cystoid macular edema in an eye with a capsule defect and posteriorly dislocated capsular tension ring

A 72-year-old man presented with visual deterioration and cystoid macular edema (CME) 9 months after cataract surgery elsewhere. A slitlamp examination showed a large posterior capsule defect and a slightly decentered intraocular lens (IOL). In addition, a curved poly(methyl methacrylate) (PMMA) haptic-like structure was seen behind the IOL in the superoanterior vitreous cavity. The foreign body was entangled by vitreous fibers and moved in accordance with ocular motility. A broken PMMA haptic was suspected. During vitrectomy for removal of the suspected IOL haptic, an intact, posteriorly dislocated capsular tension ring (CTR) was found. It was cut in 2 and excised carefully via the sclerectomies. Postoperatively, the CME resolved and vision improved.

Management of posterior polar cataract

In this technique for managing posterior polar cataract, extreme care is taken not to overpressurize the anterior chamber or capsular bag to prevent posterior capsule rupture. Minimal hydrodissection and hydrodelineation are performed. The nucleus is extracted using minimal ultrasound energy. Viscodissection is used as a primary technique to mobilize the epinucleus and cortex. A protective layer is preserved over the posterior polar region until the conclusion of the extraction procedure to minimize the risk of loss of lens material into the vitreous cavity in the case of a capsule defect.

Spontaneous defects of the lateral skull base. 2. Etiology and review of the literature

Isolated cases of spontaneous cerebrospinal fluid otorrhea (SCFO) of temporal bone origin with or without meningo(encephalo)cele have been reported. Diagnosis is predicted on a high index of suspicion. Since meningitis may occur secondary to SCFO, optimal therapy with surgical closure of the defect should immediately be performed. This study was undertaken to evaluate the incidence, characteristics and type of SCFO in literature. We reviewed the reports on SCFO in the world literature since the first description in 1897 by Escat. Clinical presentation, gender, age and surgical management were aspects of our classification. Not included were patients with cerebrospinal fluid leak following any kind of previous temporal bone surgery, head trauma or rupture of the round window membrane. A total of 241 CSFO in 236 patients were found to accomplish the search criteria. Gender was not found to be a risk factor. Two subtypes of SCFO exist: the majority (161 cases) developing through the tegmen tympani and a smaller number (80 cases) with a translabyrinthine SCFO. The latter group can be regarded as the childhood-type with congenital defects of the otic capsule (Mondini dysplasia) presenting with meningitis in 85% of all cases. Adulthood-type SCFO are typically located in the tegmen tympani area presenting with conductive hearing loss or otorrhea following tube placement in 86% of all cases. Recent literature recommends a combined (transmastoidal and middle fossa) approach for closure of defects in the tegmen. Copious otorrhea through a perforated tympanic membrane or following placement of a ventilation tube, conductive hearing loss or meningitis without impairment of cochlear or vestibular function should be regarded as warning signs for an existing SCFO in adults. Children usually present with symptoms of inner ear anomalies, meningitis and loss of cochlear-vestibular function. High-resolution computer tomography is the diagnostic procedure of choice. A follow-up of several years to disclose any recurrence of SCFO or occurrence at a different area should be considered in any patient.

A positive role for patched-smoothened signaling in promoting cell proliferation during normal head development in Drosophila.

The transmembrane receptor Patched regulates several developmental processes in both invertebrates and vertebrates. In vertebrates, Patched also acts as a tumor suppressor. The Patched pathway normally operates by negatively regulating Smoothened, a G-protein-coupled receptor; binding of Hedgehog ligand to Patched relieves this negative interaction and allows signaling by Smoothened. We show that Ptc regulates Drosophila head development by promoting cell proliferation in the eye-antennal disc. During head morphogenesis, Patched positively interacts with Smoothened, which leads to the activation of Activin type I receptor Baboon and stimulation of cell proliferation in the eye-antennal disc. Thus, loss of Ptc or Smoothened activity affects cell proliferation in the eye-antennal disc and results in adult head capsule defects. Similarly, reducing the dose of smoothened in a patched background enhances the head defects. Consistent with these results, gain-of-function Hedgehog interferes with the activation of Baboon by Patched and Smoothened, leading to a similar head capsule defect. Expression of an activated form of Baboon in the patched domain in a patched mutant background completely rescues the head defects. These results provide insight into head morphogenesis, a process we know very little about, and reveal an unexpected non-canonical positive signaling pathway in which Patched and Smoothened function to promote cell proliferation as opposed to repressing it.