Posterior capsule opacification: What's in the bag?

Cataract, a clouding of the lens, is the most common cause of blindness in the world. It has a marked impact on the wellbeing and productivity of individuals and has a major economic impact on healthcare providers. The only means of treating cataract is by surgical intervention. A modern cataract operation generates a capsular bag, which comprises a proportion of the anterior capsule and the entire posterior capsule. The bag remains in situ, partitions the aqueous and vitreous humours, and in the majority of cases, houses an intraocular lens (IOL). The production of a capsular bag following surgery permits a free passage of light along the visual axis through the transparent intraocular lens and thin acellular posterior capsule. Lens epithelial cells, however, remain attached to the anterior capsule, and in response to surgical trauma initiate a wound-healing response that ultimately leads to light scatter and a reduction in visual quality known as posterior capsule opacification (PCO). There are two commonly-described forms of PCO: fibrotic and regenerative. Fibrotic PCO follows classically defined fibrotic processes, namely hyperproliferation, matrix contraction, matrix deposition and epithelial cell trans-differentiation to a myofibroblast phenotype. Regenerative PCO is defined by lens fibre cell differentiation events that give rise to Soemmerring's ring and Elschnig's pearls and becomes evident at a later stage than the fibrotic form. Both fibrotic and regenerative forms of PCO contribute to a reduction in visual quality in patients. This review will highlight the wealth of tools available for PCO research, provide insight into our current knowledge of PCO and discuss putative management of PCO from IOL design to pharmacological interventions.

A genomic case study of mixed fibrolamellar hepatocellular carcinoma.

BACKGROUND: Mixed fibrolamellar hepatocellular carcinoma (mFL-HCC) is a rare liver tumor defined by the presence of both pure FL-HCC and conventional HCC components, represents up to 25% of cases of FL-HCC, and has been associated with worse prognosis. Recent genomic characterization of pure FL-HCC identified a highly recurrent transcript fusion (DNAJB1:PRKACA) not found in conventional HCC. PATIENTS AND METHODS: We performed exome and transcriptome sequencing of a case of mFL-HCC. A novel BAC-capture approach was developed to identify a 400 kb deletion as the underlying genomic mechanism for a DNAJB1:PRKACA fusion in this case. A sensitive Nanostring Elements assay was used to screen for this transcript fusion in a second case of mFL-HCC, 112 additional HCC samples and 44 adjacent non-tumor liver samples. RESULTS: We report the first comprehensive genomic analysis of a case of mFL-HCC. No common HCC-associated mutations were identified. The very low mutation rate of this case, large number of mostly single-copy, long-range copy number variants, and high expression of ERBB2 were more consistent with previous reports of pure FL-HCC than conventional HCC. In particular, the DNAJB1:PRKACA fusion transcript specifically associated with pure FL-HCC was detected at very high expression levels. Subsequent analysis revealed the presence of this fusion in all primary and metastatic samples, including those with mixed or conventional HCC pathology. A second case of mFL-HCC confirmed our finding that the fusion was detectable in conventional components. An expanded screen identified a third case of fusion-positive HCC, which upon review, also had both conventional and fibrolamellar features. This screen confirmed the absence of the fusion in all conventional HCC and adjacent non-tumor liver samples. CONCLUSION: These results indicate that mFL-HCC is similar to pure FL-HCC at the genomic level and the DNAJB1:PRKACA fusion can be used as a diagnostic tool for both pure and mFL-HCC.

Teachers of the Alexander Technique in the UK and the people who take their lessons: A national cross-sectional survey.

OBJECTIVES: Given the rising profile of the Alexander Technique in the UK, there is a need for a comprehensive description of its teachers and of those who currently take lessons. In a national survey of Alexander teachers, we set out to address this information gap. DESIGN: A cross-sectional survey of 871 UK members of three main Alexander Technique teachers' professional associations was conducted. A questionnaire requested information about their professional background, teaching practice and methods, and about the people who attend lessons and their reasons for seeking help. RESULTS: With an overall response rate of 61%, 534 teachers responded; 74% were female with median age of 58 years, 60% had a higher education qualification, and 95% were self-employed, many with additional non-Alexander paid employment. The majority (87%) offered lessons on their own premises or in a privately rented room, and 19% provided home visits; both individual and group lessons were provided. People who took lessons were predominantly female (66%) with a median age of 48 years, and 91% paid for their lessons privately. Nearly two-thirds (62%) began lessons for reasons related to musculoskeletal conditions, including back symptoms, posture, neck pain, and shoulder pain. Other reasons were general (18%, including well-being), performance-related (10%, including voice-, music-, and sport-related), psychological (5%) and neurological (3%). We estimate that Alexander teachers in the UK provide approximately 400,000 lessons per year. CONCLUSIONS: This study provides an overview of Alexander Technique teaching in the UK today and data that may be useful when planning future research.

The lens as a model for fibrotic disease.

Fibrosis affects multiple organs and is associated with hyperproliferation, cell transdifferentiation, matrix modification and contraction. It is therefore essential to discover the key drivers of fibrotic events, which in turn will facilitate the development of appropriate therapeutic strategies. The lens is an elegant experimental model to study the processes that give rise to fibrosis. The molecular and cellular organization of the lens is well defined and consequently modifications associated with fibrosis can be clearly assessed. Moreover, the avascular and non-innervated properties of the lens allow effective in vitro studies to be employed that complement in vivo systems and relate to clinical data. Using the lens as a model for fibrosis has direct relevance to millions affected by lens disorders, but also serves as a valuable experimental tool to understand fibrosis per se.

Characterisation of TGF-beta2 signalling and function in a human lens cell line.

There is increasing evidence implicating Transforming growth factor beta (TGF-beta) in pathological states of the lens. However, the underlying signalling mechanisms in human cells have not been fully examined. We have therefore investigated in a human lens cell line, FHL 124, the signalling characteristics of TGF-beta and Smad proteins. Moreover, we have tested the effectiveness of a fully human monoclonal anti-TGF-beta2 antibody, CAT-152, in suppressing TGF-beta2 induced changes in a number of conditions. FHL 124 cells were routinely cultured in Eagle's minimum essential medium (EMEM) supplemented with 10% FCS. Characterisation of the cell line was determined using Affymetrix gene microarrays and compared to native human lens epithelium. Cells were serum starved for 24 hr prior to exposure to TGF-beta2 in the presence and absence of CAT-152. Non-stimulated cells served as controls. Smad 4 localisation was observed by immunocytochemistry. To study Smad-dependent transcriptional activity, cells were transfected with SBE4-luc, an artificial smad-specific reporter, using Fugene-6. Transcriptional activity was determined by luciferase activity. Gene expression was assessed using reverse transcriptase-polymerase chain reaction (RT-PCR). Proliferation was determined by 3H-thymidine DNA incorporation. Growth and contraction were assessed using a scratch and patch assay. Affymettrix gene microarrays identified 99.5% homology between FHL 124 cells and the native lens epithelium with respect to expression pattern of the 22,270 genes on the chip. Moreover, FHL 124 cells expressed phenotypic markers, alphaA-crystallin and pax6 along with lens epithelial cell specific marker FoxE3. Immunocytochemical studies revealed the presence of Smad 4 which following TGF-beta2 exposure accumulated in the cell nucleus. Furthermore, Smad-dependent transcriptional activity was also stimulated. TGF-beta2 enhanced the expression of mRNA levels of alpha smooth muscle actin (alphaSMA) and connective tissue growth factor (CTGF). Exposure to TGF-beta2 resulted in a relatively small inhibition of 3H-thymidine incorporation of FHL 124 cells. However, a more marked contractile effect was also observed. In serum-supplemented medium, growth rates and TGF-beta induced contraction were enhanced. Treatment with 0.1-10 microg ml(-1) CAT-152 dose-dependently inhibited 10 ng ml(-1) TGF-beta2 induced effects in the presence and absence of serum. Exposure of FHL 124 cells to TGF-beta therefore induces Smad translocation, transcription, expression of transdifferentiation markers and induces marked contraction. Treatment with CAT-152 can effectively inhibit these responses. TGF-beta2 induced changes can also persist long after the period of exposure and when in the presence of serum TGF-beta induced contraction is enhanced. The work presented therefore demonstrates a platform technology to study TGF-beta2 signalling in human lens epithelial cells and provides evidence to show TGF-beta2 can be a potent factor in the development of posterior capsule opacification following cataract surgery.

Stress-induced ATP release from and growth modulation of human lens and retinal pigment epithelial cells.

ATP release has been shown to occur following stimulation in several cellular systems. This study was undertaken to determine if lens and retinal epithelial cells release ATP in response to physiological stresses and to elucidate a possible role for ATP. Analysis of human aqueous humour samples showed a mean ATP level of 37.8+/-7.7 nM. Hyper-osmotic stress induced a dose- and time-dependent release of ATP. Both cell types were found to proliferate in serum-free medium, and the addition of ATP and adenosine at concentrations as low as 0.1 nM inhibited growth. Gene profiling also demonstrated the presence of the ectonucleotidases CD39 and CD73 and the A1 adenosine receptor on both cell types.

Toys and confectionery--a legally hazardous combination?

"What kind of magic has Nestlé worked on FDA?" Many in the confectionery business were asking this very question after seeing the company introduce onto the market in July 1997 - without any immediate agency intervention - a chocolate product surrounding an inedible plastic sphere enclosing a toy, bearing the moniker Nestlé Magic(R). A spate of recent publicity 1 on the controversy engendered by the new product has focused public attention on a little-known provision of the Federal Food, Drug, and Cosmetic Act (FDCA), specifically section 402(d)(1). Adding fuel to the proverbial regulatory fire was the Food and Drug Administration's (FDA's) signaling of a possible reversal of its long-standing policy prohibiting the marketing of combination "confectionery and toy" products that contain nonfunctional, nonnutritive objects. After the product was launched, FDA, in response to a petition filed by Nestlé USA, stated its intention to 1) issue a guidance document that would purport to sanction such products on an interim basis, and 2) promulgate a regulation setting safety standards for such products and thereby authorize their marketing. Although Nestlé subsequently announced its withdrawal of the product,2 questions remain about the applicable law and FDA's authority. This article critically examines the agency's authority to authorize marketing of such products through a regulation that addresses the criteria set forth in section 402(d)(1).

Pituitary and ovarian hormone levels in unexplained menorrhagia.

OBJECTIVE: To compare pituitary and ovarian hormone levels in women complaining of unexplained menorrhagia with objectively heavy menstrual blood loss (greater than 80 mL) to those with normal loss, and to determine whether there is any relation between menstrual volume and important cyclic endocrine events. METHODS: Over the course of 1 month, daily plasma LH, FSH, and estradiol (E2), and salivary progesterone concentrations were determined in 20 women with a measured menstrual loss exceeding 80 mL. These were compared with values in 22 women whose loss was less than 80 mL. For all participants, we calculated correlation coefficients for measured menstrual blood loss and the mean LH peak concentration, the mean FSH peak concentration, the mean of plasma E2 concentrations from day LH -3 to +1, and the mean of salivary progesterone concentrations from day LH +2 to +10. RESULTS: There were no significant differences in the plasma concentrations of LH, FSH, or E2 or in the salivary concentrations of progesterone between those with objectively heavy loss and those with normal loss. We did not find significant relations between the measured menstrual blood loss and the mean LH and FSH peak concentrations, the plasma E2 concentrations daily around ovulation, or the salivary progesterone concentrations during the luteal phase. CONCLUSION: There does not appear to be a relation between ovarian and pituitary hormones and menstrual loss.

A randomized double blind placebo controlled trial of the effects on bone metabolism of the combination of nafarelin acetate and norethisterone.

OBJECTIVE: We observed the effects on bone metabolism of the addition of different doses of oral norethisterone during treatment with the GnRH agonist nafarelin (Synarel, Syntex). PATIENTS: Ninety-four women with a subjective complaint of heavy menstrual blood loss or objective evidence of endometriosis received intra-nasal nafarelin 400 micrograms daily for 6 months and also received, in a randomized, double blind manner, either 0.7 mg (n = 24), 1.4 mg (n = 23) or 2.45 mg (n = 23) of oral norethisterone or placebo (n = 24) daily. Follow-up was continued for a further 6 months after treatment. RESULTS: Thirty-one patients (33%) left the study prematurely and three patients were non-compliant with the study drug. By 6 months significant increases in urinary calcium/creatinine ratio were seen, compared to baseline, in the nafareline and placebo (P = 0.001, n = 14), 0.7 mg (P = 0.04, n = 13) and 1.4 mg norethisterone groups (P = 0.009, n = 17) but not in the nafarelin or 2.45 mg norethisterone groups (P = 0.72, n = 16). Densitometry of the spine, however, showed decreases at 6 months in all groups: 6.14% (P = 0.0004, n = 11), 5.46% n = 0.0006, n = 13), 3.93% (P = 0.008, n = 14) and 4.04% (P = 0.004, n = 16) for the groups receiving nafarelin and placebo, nafarelin and norethisterone 0.7, 1.4 and 2.45 mg respectively. Six months after stopping nafarelin, with or without norethisterone, bone mass was not different from baseline. CONCLUSION: The concomitant daily use of up to 2.45 mg of norethisterone does not eliminate the bone demineralization seen during GnRH agonist therapy with nafarelin in premenopausal women.