Increased presence of cells with multiple elongated processes in osteoarthritic femoral head cartilage

OBJECTIVE

This study examined the morphology of chondrocytes in articular cartilage from osteoarthritic (OA) and non-OA human femoral heads and in particular the appearance of a sub-population of cells with multiple elongated processes radiating up to 30 microm into the extracellular matrix.

METHODS

Cartilage explants were removed from 8 anatomical sites over the surface of OA (n=6) and non-OA (n=5) femoral heads. Cells were labeled for vimentin intermediate filaments and visualized using epi-fluorescence and confocal microscopy. The percentage of cells with elongated processes was correlated with macroscopic and histological indicators of osteoarthritis.

RESULTS

Cells with processes accounted for less than 10% of the total cell population in non-OA cartilage. By contrast, in the peripheral regions of the OA femoral head these cells accounted for 20-45% of the total cell population, the differences being statistically significant. These peripheral areas are habitually non-load bearing and were also the most likely to show gross fibrillation and pannus formation. A statistically significant correlation was demonstrated between the percentage of cells with processes and the histological extent of the OA degradation, quantified in terms of the Mankin score.

CONCLUSIONS

The extension of cell processes, which may be associated with localized breakdown of the pericellular matrix, will undoubtedly alter numerous aspects of cell function including phenotypic expression and mechanotransduction. Hence these significant changes in chondrocyte morphology are likely to have important implications for the aetiology of osteoarthritis and the development of potential treatment strategies.

Passage in monolayer influences the response of chondrocytes to dynamic compression

This study tests the hypothesis that expansion by passage in monolayer influences the response of isolated articular chondrocytes to dynamic compression. Chondrocytes, isolated from bovine articular cartilage, were seeded in monolayer and passaged 4 times (P1-4). For assessment of chondrocytic and fibroblastic phenotype, freshly isolated and passaged cells were seeded on glass coverslips or in 2% alginate beads and cultured for 7 days in DMEM + 10% FCS. Samples were assayed for DNA and GAG content and stained for collagen types I and II. In separate experiments, freshly isolated or passaged chondrocytes were seeded at 10 x 10(6) cells.ml(-1) in 4% cylindrical agarose constructs and subjected to 15% dynamic compressive strain at 1 Hz for 24 hours. [(3)H]-thymidine incorporation, SO(4) incorporation and nitrite release were analysed. Immediately following isolation (P0), chondrocytes seeded in alginate expressed high levels of type II collagen, but did not stain for type I collagen. Following repeat passage the cells expressed enhanced levels of type I collagen, with an associated reduction in type II collagen staining. These data indicate a modulation to a fibroblastic phenotype during monolayer expansion which was not rapidly reversed by culture in a 3D hydrogel. Dynamic compression down-regulated SO(4) incorporation at P0, but did not affect [(3)H]-thymidine incorporation. By contrast the incorporation of both SO(4) and [(3)H]-thymidine was enhanced by dynamic compression at both P1 and to a lesser extent P2. SO(4) and [(3)H]-thymidine incorporation were inhibited at P3 and P4. Nitrite release was down-regulated by dynamic compression at all passages. These data demonstrate a clear modulation in the response of bovine articular chondrocytes to dynamic compression following passage in monolayer.

Mechanical Conditioning Influences the Metabolic Response of Cell-Seeded Constructs

Injuries and degenerative diseases to load-bearing soft tissues are extremely common in hospital clinics and involve all ages of the population. Tissue engineering provides a major focus for developments within this area due to the relative failure of graft and prosthetic-based strategies. On implantation, such systems will be subjected to normal physiological forces. It is important, therefore, to understand the effects of mechanical conditioning of cells within repair systems to predict their response and ultimate success in vivo. In the current study two well-characterised model systems, involving dermal fibroblasts seeded onto silicone membranes and chondrocytes seeded in agarose constructs, have been used to study the effects of mechanical loading on cellular activity. The data presented demonstrate that both the tensile conditioning of fibroblasts in monolayer and the compressive loading of chondrocytes in three-dimensional agarose constructs produced distinct responses. In particular, the nature of the strain field associated with the tensile system is important in determining the ultimate cell response. Equally within the compressive system the influence of dynamic frequency was shown to be important. The other critical factors in determining response to both types of conditioning are associated with the age of the cell and its original location within the tissue.

Dynamic compression counteracts IL-1 beta-induced release of nitric oxide and PGE2 by superficial zone chondrocytes cultured in agarose constructs

OBJECTIVE

To examine the effect of IL-1 beta-induced *NO and PGE(2)release by stimulated superficial and deep chondrocyte/agarose constructs subjected to mechanical compression.

DESIGN

Chondrocyte sub-populations were seeded separately in agarose constructs and cultured unstrained, within a 24-well tissue culture plate, for 48 h in medium supplemented with IL-1 beta and/or L-N-(1-iminoethyl)-ornithine (L-NIO). In a separate experiment, superficial and deep cell containing constructs were subjected to 15% dynamic compressive strain at 1 Hz, for 48 h, in the presence or absence of IL-1 beta and/or L-NIO. Nitrite was measured using the Griess assay, PGE(2)release was determined using an EIA kit and [3H]-thymidine and 35SO(4)incorporation were assessed by TCA and alcian blue precipitation, respectively.

RESULTS

The current data reveal that IL-1 beta significantly enhanced *NO and PGE(2)release for superficial chondrocytes, an effect reversed with L-NIO. *NO and PGE(2)levels did not significantly change by deep cells in the presence of IL-1 beta and/or L-NIO. For both cell sub-populations, IL-1 beta inhibited cell proliferation whereas proteoglycan synthesis was not affected. Dynamic compression inhibited the release of *NO and PGE(2)in the presence and absence of IL-1 beta, for cells from both sub-populations. L-NIO reduced *NO and enhanced PGE(2)release for superficial zone chondrocytes, an effect not observed for deep cells in response to dynamic compression. The magnitude of stimulation of [3H]-thymidine incorporation was similar for both cell sub-populations and was not influenced by L-NIO, indicating an z.rad;NO-independent pathway. The dynamic compression-induced stimulation of 35SO(4)incorporation was enhanced with L-NIO for IL-1 beta-stimulated deep cells, indicating an *NO-dependent pathway.

CONCLUSION

The present findings suggest that dynamic compression inhibits *NO and PGE(2)release in IL-1 beta-stimulated superficial cells via distinct pathways, a significant finding that may contribute to the development of intervention strategies for the treatment of inflammatory joint disorders.

Temporal regulation of chondrocyte metabolism in agarose constructs subjected to dynamic compression

The temporal response of chondrocyte metabolism in agarose constructs subjected to different dynamic compression regimes was investigated. The current study explored the effects of continuous or intermittent compression using various duty cycles of dynamic compressive loading, over a 48 h culture period. For the continuous compression experiments, duty cycles ranged from 5400 to 172,800 and intermittent compression delivered a total of 86,400 cycles. Large numbers of duty cycles significantly stimulated proteoglycan synthesis with maximal levels obtained for constructs subjected to 12h of intermittent compression. The shortest duration of intermittent compression suggested that further cycles are inhibitory for cell proliferation. Nitrite release was independent of the length or type of compressive regime applied. The uncoupled nature of the metabolic response determined in this study suggests that mechanical conditioning regimes may be fine tuned to selectively stimulate key metabolic parameters of relevance to cartilage tissue engineering.

ars1, an Arabidopsis mutant exhibiting increased tolerance to arsenate and increased phosphate uptake

Arsenic is one of the most toxic pollutants at contaminated sites, yet little is known about the mechanisms by which certain plants survive exposure to high arsenic levels. To gain insight into the mechanisms of arsenic tolerance in plants, we developed a genetic screen to isolate Arabidopsis thaliana mutants with altered tolerance to arsenic. We report here on the isolation of a mutant arsenic resisant 1 (ars1) with increased tolerance to arsenate. ars1 germinates and develops under conditions that completely inhibit growth of wild-type plants and shows a semi-dominant arsenic resistance phenotype. ars1 accumulates levels of arsenic similar to that accumulated by wild-type plants, suggesting that ars1 plants have an increased ability to detoxify arsenate. However, ars1 plants produce phytochelatin levels similar to levels produced by the wild type, and the enhanced resistance of ars1 is not abolished by the gamma-glutamylcysteine synthetase inhibitor l-buthionine sulfoxime (BSO). Furthermore, ars1 plants do not show resistance to arsenite or other toxic metals such as cadmium and chromium. However, ars1 plants do show a higher rate of phosphate uptake than that shown by wild-type plants, and wild-type plants grown with an excess of phosphate show increased tolerance to arsenate. Traditional models of arsenate tolerance in plants are based on the suppression of phosphate uptake pathways and consequently on the reduced uptake of arsenate. Our data suggest that arsenate tolerance in ars1 could be due to a new mechanism mediated by increased phosphate uptake in ars1. Models discussing how increased phosphate uptake could contribute to arsenate tolerance are discussed.

Long-distance root-to-shoot transport of phytochelatins and cadmium in Arabidopsis

Phytochelatin synthases (PCS) mediate cellular heavy-metal resistance in plants, fungi, and worms. However, phytochelatins (PCs) are generally considered to function as intracellular heavy-metal detoxification mechanisms, and whether long-distance transport of PCs occurs during heavy-metal detoxification remains unknown. Here, wheat TaPCS1 cDNA expression was either targeted to Arabidopsis roots with the Arabidopsis alcohol dehydrogenase (Adh) promoter (Adh::TaPCS1/cad1-3) or ectopically expressed with the cauliflower mosaic virus 35S promoter (35S::TaPCS1/cad1-3) in the PC-deficient mutant cad1-3. Adh::TaPCS1/cad1-3 and 35S::TaPCS1/cad1-3 complemented the cadmium, mercury, and arsenic sensitivities of the cad1-3 mutant. Northern blot, RT-PCR, and Western blot analyses showed Adh promoter-driven TaPCS1 expression only in roots and thus demonstrated lack of long-distance TaPCS1 mRNA and protein transport in plants. Fluorescence HPLC analyses showed that under Cd2+ stress, no PCs were detectable in cad1-3. However, in Adh::TaPCS1/cad1-3 plants, PCs were detected in roots and in rosette leaves and stems. Inductively coupled plasma atomic emission spectrometer analyses showed that either root-specific or ectopic expression of TaPCS1 significantly enhanced long-distance Cd2+ transport into stems and rosette leaves. Unexpectedly, transgenic expression of TaPCS1 reduced Cd2+ accumulation in roots compared with cad1-3. The reduced Cd2+ accumulation in roots and enhanced root-to-shoot Cd2+ transport in transgenic plants were abrogated by l-buthionine sulfoximine. The presented findings show that (i) transgenic expression of TaPCS1 suppresses the heavy-metal sensitivity of cad1-3, (ii) PCs can be transported from roots to shoots, and (iii) transgenic expression of the TaPCS1 gene increases long-distance root-to-shoot Cd2+ transport and reduces Cd2+ accumulation in roots.

Dynamic compressive strain inhibits nitric oxide synthesis by equine chondrocytes isolated from different areas of the cartilage surface

REASONS FOR PERFORMING STUDY

Chondrocytes within articular cartilage respond to the mechanical stresses associated with normal joint loading via a series of signalling pathways. Specific biomolecules, such as nitric oxide (NO), have been implicated in these mechanotransduction processes. It has been shown that the synthesis of NO can be inhibited by dynamic compressive strain of chondrocytes in vitro which, in turn, leads to an up-regulation of specific metabolic parameters.

HYPOTHESIS

Chondrocytes isolated from different joint locations and seeded in agarose constructs respond in a distinct manner to the application of dynamic compression.

METHODS

Chondrocytes were isolated separately from the equine patella groove and the femoral condyle, representing high loaded areas (HLA) and low loaded areas (LLA), respectively, of 6 specimens of different ages. The cells were seeded in agarose constructs and cultured either in an unstrained state or strained under dynamic loading at 1 Hz for 48 h. The synthesis of nitric oxide (NO), proteoglycan synthesis and chondrocyte proliferation were assessed.

RESULTS

Equine chondrocytes were found to synthesise significant basal levels of NO, regardless of topographical origin or age of tissue. Marked differences in both proteoglycan synthesis and cell proliferation were, however, revealed between the 2 chondrocyte subpopulations. Dynamic compression inhibited NO synthesis but significant alterations in proteoglycan synthesis and cell proliferation were apparent in a minority of cases.

CONCLUSIONS AND POTENTIAL RELEVANCE

The differential response of the subpopulations of chondrocytes derived from the HLA and LLA provides a potential mechanism which enables the biomechanical demands of differing joint regions to be maintained.

Mycotic aneurysm of the descending thoracic aorta caused by Pseudomonas aeruginosa in a solid organ transplant recipient: case report and review

BACKGROUND

Pseudomonas aeruginosa is a rare cause of aortic mycotic aneurysms. Optimal treatment, including reconstructive graft material and appropriate length of antibiotic therapy, is being debated.

METHODS

We describe a 26-year-old kidney-pancreas recipient who developed an aneurysm of the descending thoracic aorta caused by P. aeruginosa.

RESULTS

After surgical debridement and cryopreserved allograft reconstruction, parenteral antibiotics were continued for 12 months, at which time the patient was converted to oral antibiotic therapy. Within 6 months, he redeveloped a thoracic aortic aneurysm, necessitating reoperation and lifelong parenteral antibiotic therapy.

CONCLUSION

Herein we review and discuss the relevant literature concerning surgical and antibiotic treatment of mycotic thoracic aneurysms.

Live cell imaging using confocal microscopy induces intracellular calcium transients and cell death

Isolated chondrocytes stained with fluo 4-AM and visualized using standard confocal microscopy techniques exhibited Ca2- transients and oscillations. Decreasing the power of the laser light decreased the percent-age of cells exhibiting these Ca2+ signals. Treatment with the antioxidant ascorbate reduced the Ca2+ response, suggesting that it was mediated by light-induced release of reactive oxygen species (ROS). Cell viability 24 h after the 1-h confocal imaging period was approximately 90% for cells that were neither fluorescently stained nor subjected to laser excitation. By contrast, fluorescently stained cells imaged for 1 h exhibited greatly reduced viability. Treatment with ascorbate reduced the level of cell death, suggesting that the effect was mediated by release of exogenous ROS associated with the interaction of light and the fluorochrome. Ca2+ oscillations were not always associated with cell death, suggesting that separate light-sensitive pathways mediate the two processes. Light-activated Ca2+ signaling may trigger alterations in numerous cell processes and thereby represent an important and hitherto overlooked artifact in fluorescent microscopy of viable cells.

Dermal fibroblasts respond to mechanical conditioning in a strain profile dependent manner

Fibroblasts within tissues are exposed to a dynamic mechanical environment, which influences the structural integrity of both healthy and healing soft tissues. Various systems have been proposed to subject such cells to mechanical stimulation in culture. However the diverse nature of the studies, in terms of the strain profiles and the cell types, makes direct comparisons almost impossible. The present study addresses this issue by examining the metabolic response of two cell types subjected to three well defined strain profiles.A young fibroblast cell population, represented by HuFFs, showed both greater cell proliferation and collagen production than adult dermal fibroblasts under unstrained conditions. The three strain profiles produced differing effects on both cell types. Uniaxial strains enhanced [(3)H]-thymidine incorporation for both cell types, whilst biaxial strains either inhibited or had no effect on its incorporation. In contrast, [(3)H]-proline incorporation was inhibited under biaxial and uniaxial strains for the adult fibroblasts, whilst the HuFF cells showed a small increase in proline incorporation under non-uniform and uniaxial strains.

Development of a technique to determine strains in tendons using the cell nuclei

Tenocytes detect mechanical stimuli in vivo, and respond through mechanotransduction pathways to initiate matrix remodelling in tendons. Due to the crimped nature of tendon fascicles, the strain field throughout is non-homogeneous. The present study has developed a means to quantify the local strain fields within a fascicle by monitoring the relative movement and deformation of fluorescently labelled tenocyte nuclei. A stage mounted test rig was designed to apply tensile strain to fascicles. Rat tail and bovine extensor tendons were harvested for analysis, and the cell nuclei stained and visualised using an inverted confocal microscope. As the fascicles were subjected to gross strains of up to 5%, the movement of selected tenocyte nuclei were recorded. Results from a series of cell nuclei from both tendon sources revealed that local strains were significantly less than the applied strain. The nuclei length to width ratio, an indicator of cell deformation, also increased with applied strain, most significantly between 2 and 3% applied strain.

Expansion of chondrocytes for tissue engineering in alginate beads enhances chondrocytic phenotype compared to conventional monolayer techniques

Chondrocytes are known to dedifferentiate when cultured in monolayer culture, which may compromise the efficacy of cartilage repair systems in which cells are expanded by repeat passage in monolayer prior to implantation. We tested the hypothesis that repeat passage in alginate beads can provide sufficient expansion of cells, while producing cells with enhanced chondrocytic phenotype. Bovine articular chondrocytes were seeded in 2% alginate beads or in monolayer. 4 passages at 7-day intervals were performed. Values of 9.1 days for monolayer expansion and 12.5 days for alginate expansion were estimated for a 10-fold increase in cell number. For assessment of chondrocytic and fibroblastic phenotype, expanded cells were seeded in alginate beads or on glass coverslips and cultured for 7 days. On subsequent seeding in alginate, cells which had previously been subcultured in alginate showed higher levels of both DNA and GAG synthesis than cells passaged in monolayer. Furthermore, the alginate-passaged cells retained a chondrocytic phenotype, indicated by synthesis of type II collagen and chondroitin-6-sulphate, while cells passaged inmonolayer synthesised type I collagen, indicating a fibroblastic phenotype. In conclusion, expansion of cells for autologous cartilage repair systems, using subculture within alginate beads, provides a potentially attractive alternative to monolayer expansion.

Automated perimetry: a report by the American Academy of Ophthalmology

OBJECTIVE

The purpose of this document is to summarize and evaluate the effectiveness of new automated perimetry tests and algorithms in diagnosing glaucoma and detecting disease progression.

METHODS

A literature search on automated perimetry retrieved over 300 citations from 1994 to 2001, of which 71 were selected as relevant to this assessment. The quality of the evidence obtained from these studies was assessed by the methodologist.

RESULTS

The four automated perimetry techniques described in this assessment are short wavelength automated perimetry (SWAP), frequency doubling technology perimetry (FDT), high-pass resolution perimetry (HPRP), and motion automated perimetry (MAP). The algorithms described are Swedish interactive threshold algorithm (SITA) and SITA fast. With the exception of SWAP, these techniques and algorithms reduce testing time and inconsistent patient performance when compared with conventional full threshold testing.

CONCLUSIONS

Short wavelength automated perimetry detected visual field loss earlier than standard threshold automated perimetry, with a sensitivity and specificity of about 88% and 92% respectively. However, it is a lengthy, demanding test, is sensitive to media opacities, and has a greater magnitude of long-term fluctuation compared with standard threshold automated perimetry, which make it difficult to assess disease progression accurately. When compared to standard threshold automated perimetry, FDT perimetry showed sensitivity and specificity greater than 97% for detecting moderate and advanced glaucoma, and sensitivity of 85% and specificity of 90% for early glaucoma. As FDT perimetry has a short testing time and is resistant to blur and pupil size, it may be a useful screening tool. In a longitudinal study, high-pass resolution perimetry was more effective than standard threshold automated perimetry in monitoring progressive glaucomatous loss, detecting progression at a median of 12 months earlier in 54% of patients studied. Motion automated perimetry demonstrated usefulness in detecting early glaucomatous visual loss in a longitudinal study. Studies on SITA demonstrated greater sensitivity and reproducibility and less intertest variability when compared to standard full threshold testing and a 50% reduction in testing times. A study comparing standard full threshold, SITA, and SITA fast found a sensitivity of 95% for the first two techniques and 93% for SITA fast. Long-term follow-up studies are needed to assess the ability of these techniques to detect progression of glaucoma over time.

Deformation properties of articular chondrocytes: a critique of three separate techniques

This paper presents a series of techniques, which examine the deformation characteristics of bovine articular chondrocytes. The direct contact approach employs well established methodology, involving AFM and micropipette aspiration, to yield structural properties of local regions of isolated chondrocytes. The former technique yields a non-linear response with increased structural stiffness in a central location on a projected image of the chondrocyte. A simple viscoelastic model can be used with data from the micropipette aspiration technique to yield a mean value of Young's modulus, which is similar to that recently reported (Jones et al., 1999). An indirect approach is also described, involving the response of chondrocytes seeded within compressed agarose constructs. For 1% agarose constructs, the resulting cell strain, yields a gross cell modulus of 2.7 kPa. The study highlights the difficulties in establishing unique mechanical parameters, which reflect the deformation behaviour of articular chondrocytes.

Cell and nucleus deformation in compressed chondrocyte-alginate constructs: temporal changes and calculation of cell modulus

Mechanical loading is essential for the homeostasis of articular cartilage and may be necessary for achieving functional tissue engineered cartilage repair using isolated cells seeded in scaffolds such as alginate. Chondrocyte mechanotransduction is poorly understood, but may involve cell deformation and associated distortion of intracellular organelles. The present study used confocal microscopy to examine cell and nucleus morphology in isolated chondrocytes compressed in alginate constructs. Compression of 2% alginate resulted in cell deformation from a spherical to an oblate ellipsoid morphology with conservation of cell volume. Cell deformation was associated with deformation, to a lesser degree, of the nucleus. Despite constant cell deformation over a 25 min period of static compression, the nucleus deformation reduced significantly, particularly in the axis perpendicular to the applied compression. Constructs made of a lower alginate concentration exhibited a reduced compressive modulus with an altered cellular response to compression. In 1.2% alginate, compression resulted in cell deformation which was initially of a similar magnitude to that in 2% alginate but subsequently reduced over a 60 min period reflecting the viscoelastic behaviour of the gel. This phenomenon enabled the calculation of a stress-strain relationship for the cell with an estimated Young's modulus value of approx. 3 kPa.

The role of shame and guilt in traumatic events: a clinical model of shame-based and guilt-based PTSD

Post-traumatic stress disorder is currently classified as an anxiety disorder with fear as the predominant emotion. This has led to the development of treatment techniques such as exposure aimed at alleviating fear. This article highlights the need to address other emotional responses, in particular shame and guilt, when assessing and treating PTSD. Hence, it presents two clinical models of shame-based PTSD and guilt-based PTSD. These models are offered as aids to clinicians in assessing and formulating cases of PTSD where shame and guilt are salient issues. The models highlight the importance of assessing meaning in the context of pre-existing schemas and address two pathways to the development of shame and/or guilt: schema congruence and schema incongruence. Several treatment implications are drawn from the models.

Cyclophotocoagulation: a report by the American Academy of Ophthalmology

OBJECTIVE

This document describes cyclophotocoagulation procedures for glaucoma and examines the evidence to answer key questions about patient selection, and efficacy of transscleral and endoscopic techniques.

METHODS

A literature search conducted for the years 1968 to 2000 retrieved 130 citations. The author reviewed 34 of these articles and selected 19 for the panel methodologist to review and rate according to the strength of evidence. A Level I rating is assigned to properly conducted, well-designed, randomized clinical trials; a Level II rating is assigned to well-designed cohort and case-control studies; and a Level III rating is assigned to case series and poorly designed prospective and retrospective studies, including case-control studies.

RESULTS

The predominant problem with all studies on cyclophotocoagulation is the lack of a uniform definition of success, which makes comparisons difficult. One randomized controlled trial (Level I evidence) compared the efficacy of transscleral cyclophotocoagulation with noncontact Nd:YAG and semiconductor diode laser. It found no significant difference between the two, although a significant problem was the variability allowed with laser parameters. Most of the literature consists of noncomparative case series that provide evidence that is limited and often not convincing.

CONCLUSION

Cyclophotocoagulation is indicated for patients with refractory glaucoma who have failed trabeculectomy or tube shunt procedures, patients with minimal useful vision and elevated intraocular pressure, and patients who have no visual potential and need pain relief (based on Level III evidence). It may be useful for patients whose general medical condition precludes invasive surgery or who refuse more aggressive surgery (i.e., filter or tube). It is also useful in emergent situations, such as the acute onset of neovascular glaucoma. There is insufficient evidence to definitively compare the relative efficacy of the cyclophotocoagulation procedures for glaucoma. It is the panel's opinion, however, that semiconductor diode systems appear to possess the best combination of effectiveness (based on Level III evidence), portability, expense, and ease of use at this time.

Effects of tissue transglutaminase on retinoic acid-induced cellular differentiation and protection against apoptosis

Retinoic acid (RA) and its various synthetic analogs affect mammalian cell growth, differentiation, and apoptosis. Whereas treatment of the human leukemia cell line HL60 with RA results in cellular differentiation, addition of the synthetic retinoid, N-(4-hydroxyphenyl) retinamide (HPR), induces HL60 cells to undergo apoptosis. Moreover, pretreatment of HL60 cells as well as other cell lines (i.e. NIH3T3 cells) with RA blocks HPR-induced cell death. In attempting to discover the underlying biochemical activities that might account for these cellular effects, we found that monodansylcadaverine (MDC), which binds to the enzyme (transamidase) active site of tissue transglutaminase (TGase), eliminated RA protection against cell death and in fact caused RA to become an apoptotic factor, suggesting that the ability of RA to protect against apoptosis is linked to the expression of active TGase. Furthermore, it was determined that expression of exogenous TGase in cells exhibited enhanced GTP binding and transamidation activities and mimicked the survival advantage imparted by RA. We tested whether the ability of this dual function enzyme to limit HPR-mediated apoptosis was a result of the ability of TGase to bind GTP and/or catalyze transamidation and found that GTP binding was sufficient for the protective effect. Moreover, excessive transamidation activity did not appear to be detrimental to cell viability. These findings, taken together with observations that the TGase is frequently up-regulated by environmental stresses, suggest that TGase may function to ensure cell survival under conditions of differentiation and cell stress.

Dynamic compression inhibits the synthesis of nitric oxide and PGE(2) by IL-1beta-stimulated chondrocytes cultured in agarose constructs

Both mechanical loading and interleukin-1beta (IL-1beta) are known to regulate metabolic processes in articular cartilage through pathways mediated by nitric oxide ((*)NO) and PGE(2). This study uses a well-characterized model system involving isolated chondrocytes cultured in agarose constructs to test the hypothesis that dynamic compression alters the synthesis of (*)NO and PGE(2) by IL-1beta-stimulated articular chondrocytes. The data presented demonstrate for the first time that dynamic compression counteracts the effects of IL-1beta on articular chondrocytes by suppressing both (*)NO and PGE(2) synthesis. Inhibitor experiments indicated that the dynamic compression-induced inhibition of PGE(2) synthesis and stimulation of proteoglycan synthesis were (*)NO mediated, while compression-induced stimulation of cell proliferation was (*)NO independent. The inhibition of (*)NO and PGE(2) by dynamic compression is a finding of major significance that could contribute to the development of novel strategies for the treatment of cartilage-degenerative disorders.

Eye conditions among 5- to 7-year-old Asian-Pacific Islander schoolchildren in Southern California

BACKGROUND

The prevalence rates and specific risk factors for development of eye conditions among Asian-Pacific Islander schoolchildren are unknown. This information is necessary to understand their eye care needs and to improve access to eye care for this rapidly growing population.

METHODS

Data obtained from a computer database of vision screening examinations conducted by the UCLA Mobile Eye Clinic from October 1987 through December 1996 were analyzed for 2,687 Asian-Pacific Islander schoolchildren between 5 and 7 years of age.

RESULTS

Myopia (8.9%) and astigmatism (15.8%) represented the majority of visual disorders. Mean myopic refractive error was -1.21 +/- 0.83 D among bilateral myopes. Color-vision deficiency was prevalent among 2.8% of male children, extraocular muscle imbalance among 3.0% of children, and amblyopia among 1.0% of children. All other conditions were present in less than 4% of children screened.

CONCLUSIONS

Asian-Pacific Islander schoolchildren may be at higher risk for development of juvenile myopia than white, Hispanic, and African-American children. Prevalence rates of other disorders are comparable to those obtained for other ethnic groups. This information can be used in planning to meet the eye care needs of Asian-Pacific Islander schoolchildren.

Effectiveness and safety of brimonidine as adjunctive therapy for patients with elevated intraocular pressure in a large, open-label community trial

PURPOSE

To determine the effectiveness and safety of brimonidine when used in combination with one or more glaucoma medications in patients with glaucoma or ocular hypertension.

METHODS

Post hoc analysis of a multicenter, 2-month, open-label, prospective, clinical trial in which 2,335 patients received brimonidine as monotherapy, replacement therapy, or combination therapy. Patients who received brimonidine as combination therapy (n = 554) were examined in the current analysis. Efficacy was determined by the reduction in intraocular pressure (IOP) from baseline before the addition of brimonidine. Safety and tolerability parameters included adverse events and quality-of-life measures (e.g., ocular comfort, energy level, breathing ability, night vision).

RESULTS

Addition of brimonidine to preexisting regimens resulted in an overall mean additional reduction in IOP of 17.9% (4.26 mm Hg) at month 2 (P < 0.001). Significant additional IOP lowering was provided by brimonidine in combination with each preexisting regimen evaluated (P < or = 0.061). When brimonidine was added to monotherapy with a nonselective beta-blocker, the mean additional IOP reduction was 15.5% (3.61 mm Hg, P < 0.001). Addition of brimonidine to latanoprost monotherapy provided a 32.2% (5.89 mm Hg) mean additional IOP reduction (P < 0.001). Addition of brimonidine to combination regimens that included latanoprost provided additional mean decreases in LOP ranging from 15.5% (3.63 mm Hg, P < 0.002) to 20.1% (6.62 mm Hg, P < 0.001). All quality-of-life parameters remained high or improved during the study. Mild to moderate adverse events were reported in 5.23% of patients (29 of 552); 98.1% of physicians rated brimonidine adjunctive therapy as good or excellent.

CONCLUSIONS

Brimonidine, when added to existing glaucoma regimens, safely and effectively lowered IOP in this community-based trial.

Chondrocyte deformation within mechanically and enzymatically extracted chondrons compressed in agarose

Within articular cartilage, the chondron microenvironment will influence chondrocyte behaviour and response to loading. Chondrons were extracted from intact cartilage using either mechanical homogenisation (MC) or enzymatic digestion (EC) and cell and matrix morphology in unstrained and compressed agarose constructs was examined. Isolated chondrocytes (IC) were used for comparison. Immunolocalisation of type VI collagen and keratan sulphate revealed differences in the structure of the pericellular microenvironment such that MC most closely resembled chondrons in situ. The unstrained cell diameters of IC and EC were larger than MC at day 1 and increased significantly over a 7 day culture period. In contrast, cell diameters for MC remained constant. Compression of constructs at day 1 resulted in cell deformation for IC and EC but not MC. The two chondron extraction methods yielded chondrons of differing matrix morphology and associated differences in cell size and cellular response to load. The results indicate that the pericellular microenvironment of MC initially possessed a greater mechanical integrity than that of EC. Although these differences may be reduced with time in culture, characterisation of mechanically isolated chondrons suggests that the stiffness of the chondrons in situ may be greater than previous estimates.

Temporal changes in cytoskeletal organisation within isolated chondrocytes quantified using a novel image analysis technique

This paper examines temporal changes in the organisation of the cytoskeleton within isolated articular chondrocytes cultured for up to 7 days in agarose constructs. Fluorescent labelling and confocal microscopy were employed to visualise microtubules (MT), vimentin intermediate filaments (VIF) and actin microfilaments (AMF). To quantify the degree of cytoskeletal organisation within populations of cells, a novel image analysis technique has been developed and fully characterised. Organisation was quantified in terms of an Edge Index, which reflects the density of 'edges' present within the confocal images as defined by a Sobel digital filter. This parameter was shown to be independent of image intensity and, for all three cytoskeletal components, was validated statistically against a visual assessment of organisation. Both MT and VIF exhibited fibrous networks extending throughout the cytoplasm, while AMF appeared as punctate units associated with the cell membrane. The use of the Edge Index parameter revealed statistical significant temporal variation, in particular associated with VIF and AMF. These findings indicate the possibility of cytoskeletal mediated temporal variation in many aspects of cell behaviour following isolation from the intact tissue. Furthermore, the image analysis techniques are likely to be useful for future studies aiming to quantify changes in cytoskeletal organisation.

Mechanical compression influences intracellular Ca2+ signaling in chondrocytes seeded in agarose constructs

Ca2+ signaling forms part of a possible mechanotransduction pathway by which chondrocytes may alter their metabolism in response to mechanical loading. In this study, a well-characterized model system utilizing bovine articular chondrocytes embedded in 4% agarose constructs was used to investigate the effect of physiological mechanical compressive strain applied after 1 and 3 days in culture. The intracellular Ca2+ concentration was measured by use of the ratiometric Ca2+ indicator indo 1-AM and confocal microscopy. A positive Ca2+ response was defined as a percent increase in Ca2+ ratio above a preset threshold. A significantly greater percentage of cells exhibited a positive Ca2+ response in strained constructs compared with unstrained controls at both time points. In strained constructs, treatment with either Ga3+ or EGTA significantly reduced the number of positive Ca2+ responders compared with untreated controls. These results represent an important step in understanding the physiological role of intracellular Ca2+ in chondrocytes under mechanical compression.

Compressive deformation and damage of muscle cell subpopulations in a model system

To study the effects of compressive straining on muscle cell deformation and damage an in vitro model system was developed. Myoblasts were seeded in agarose constructs and cultured in growth medium for 4 days. Subsequently, the cells were allowed to fuse into multinucleated myotubes for 8 days in differentiation medium, resulting in a population of spherical myoblasts (50%), spherical myotubes (35%), and elongated myotubes (15%) with an overall viability of 90%. To evaluate cell deformation upon construct compression half-core shaped constructs were compressed up to 40% strain and the resulting cell shape was assessed from confocal scans through the central plane of spherical cells. The ratio of cell diameters measured parallel and perpendicular to the axis of compression was used as an index of deformation (DI). The average DI of myoblasts decreased with strain level (0.99+/-0.03, 0.70+/-0.04, and 0.56+/-0.10 at 0%, 20%, and 40% strain), whereas for myotubes DI decreased up to 20% strain and then remained fairly constant (0.99+/-0.06, 0.55+/-0.06, 0.50+/-0.11). The discrepancy in DI between spherical myoblasts and myotubes at 20% strain was explained by the relative sensitivity of the cell membrane to buckling, which is more pronounced in the myotubes. Sustained compression up to 24 h at 20% strain resulted in a significant increase in cell damage with time as compared to unstrained controls. Despite differences in membrane buckling no difference in damage between myoblasts and spherical myotubes was observed over time, whereas the elongated myotubes were more susceptible to damage.

Reduced nerve growth factor in Rett syndrome postmortem brain tissue

To determine whether reduced nerve growth factor (NGF) and/or its high affinity receptor, trkA, play a role in the pathophysiology of Rett syndrome (RS), we used immunohistochemistry in paraffin-embedded human autopsy brain tissue, to quantify NGF and trkA levels within the frontal cortex of 9 RS females and 10 female controls of similar age. The results showed a significant reduction of NGF expression in RS patients (p < 0.001). Specifically, all RS brains exhibited NGF levels at or below the minimum level observed in controls. In 3 RS brains there was no NGF detected. TrkA expression was also reduced in the RS group (p = 0.035). Interestingly, the expression of NGF in the RS group was significantly related to the presence of cortical astrogliosis (r = 0.91) as indicated by immunostaining for glial fibrillary acidic protein (GFAP). This suggests that while the signals for NGF production during injury remain intact, the critical developmental signals required for early NGF production are impaired.

Assessment of ganaxolone's anticonvulsant activity using a randomized, double-blind, presurgical trial design. Ganaxolone Presurgical Study Group

PURPOSE

A double-blind, randomized, placebo-controlled clinical trial to examine the safety, tolerability, and antiepileptic activity of ganaxolone in patients after withdrawal from other antiepileptic drugs during presurgical evaluations was performed.

METHODS

Fifty-two eligible patients were withdrawn from antiepileptic drugs and randomized to receive ganaxolone (24 patients) or placebo (28 patients) for up to 8 days. Ganaxolone was administered at a dose of 1500 mg/d on day 1 and 1875 mg/d on days 2 to 8. Dosing occurred three times per day: immediately after breakfast, lunch, and dinner.

RESULTS

The primary measure of antiepileptic activity was duration of treatment before withdrawal from the trial. Kaplan-Meier curves depicted a clear separation between treatment groups, with 50% of the ganaxolone-treated patients completing the entire study, compared with 25% of patients treated with placebo. Intent-to-treat survival analyses revealed a trend toward efficacy with ganaxolone (p = 0.0795, log rank test). Covariate analyses revealed a significant treatment effect on survival time in men (p = 0.03). Post-hoc chi2 probe analyses focusing on patients who completed the entire study revealed a significant difference (p = 0.04) between treatment groups. The tolerability of ganaxolone was similar to that of placebo, with adverse events being reported by 79% of patients in the ganaxolone group and 68% of patients in the placebo group.

CONCLUSIONS

Ganaxolone monotherapy was well tolerated for the duration of this clinical trial, and the results provide preliminary evidence that ganaxolone does have antiepileptic activity.

The influence of mechanical loading on isolated chondrocytes seeded in agarose constructs

Articular cartilage is subjected to dynamic compressive loading during normal activity which influences chondrocyte metabolism through various mechanotransduction pathways. A well characterised and reproducible model system, involving chondrocytes embedded in agarose gel, has been used to investigate the effects of mechanical compression on chondrocytes, isolated from full depth cartilage or separately from the superficial and deep zone tissue. The role of nitric oxide as a mediator of mechanical-induced effects has also been studied. Chondrocytes were isolated, separately, from full depth, superficial and deep zone cartilage and seeded in 3% agarose constructs. Dynamic compressive strain was applied to the constructs using a range of frequencies (0.3, 1 and 3 Hz). Glycosaminoglycan synthesis, cell proliferation and nitrite production were assessed. In further experiments, constructs were compressed in the presence of 1 mM L-NAME or 10 microM dexamethasone. Glycosaminoglycan synthesis by full depth chondrocytes was affected by compressive strain in a frequency dependent manner. Dynamic strain at all frequencies induced an increase in [3H]-thymidine incorporation. Glycosaminoglycan synthesis by deep zone cells was affected by the strain regimes in a similar fashion to full depth cells, while superficial cells exhibited a similar proliferative response to full depth cells. Dynamic compression inhibited nitrite production, the effect being reversed by L-NAME. Compression induced stimulation of [3H]-TdR incorporation was reversed by L-NAME. These studies demonstrate that glycosaminoglycan synthesis and proliferation are influenced by the dynamic strain regimes in a distinct manner. Indeed the data suggest that these processes occur in different chondrocyte sub-populations. It may be speculated that nitric oxide acts as a mediator of mechanotransduction processes affecting proliferation primarily in the superficial cell sub-population.

A system for monitoring the response of uniaxial strain on cell seeded collagen gels

The success of cell seeded constructs for the repair of collagenous tissues may be improved by the use of mechanical stimulation in vitro. A mechanical loading apparatus, termed the cell straining system, was developed according to a set of design criteria, to enable cell seeded constructs to be cyclically loaded in tension. A suitable cell seeded collagen gel model system was used to characterise the apparatus. These gels were subjected to a cyclic strain of 10% superimposed on two separate tare loads of 2 and 10 mN, while being maintained in cell culture conditions. The computer controlled apparatus was shown to be capable of monitoring the individual loads on six specimens simultaneously, to an accuracy of 0.02 mN. Results indicated a wide variability between individual specimens. Following cyclic loading, the cell seeded collagen gels exhibited an increase in structural stiffness compared with the unloaded controls. This novel and versatile apparatus will provide a means of enhancing structural and mechanical integrity of tissue engineered repair systems.

Postoperative Descemet membrane detachment with maintenance of corneal clarity after trabeculectomy

This case report describes an unusual complication of Descemet membrane detachment after anterior chamber reformation to treat a flat anterior chamber and hypotony from a trabeculectomy. This large Descemet membrane detachment was unexpectedly associated with a clear cornea. Treatment was conservative, and the Descemet membrane detachment spontaneously resolved in 6 months.

Collagen degradation in glaucoma: will it gain a therapeutic value?

The extracellular matrix is in a constant state of turnover, and several studies suggest that this homeostasis is out of balance in open-angle glaucoma. Recent evidence suggests that matrix metalloproteinases, which are the enzymes primarily responsible for degradation, play a role in numerous modern glaucoma therapies, including topical prostaglandin analogues, topical steroids, and argon laser trabeculoplasty. Additionally, direct and indirect regulation of this system has been shown to increase aqueous humor outflow facility. It is possible that therapies directed at modulating specific enzymes represent the next generation of glaucoma therapy.

The effect of integrin antibodies on the attachment and proliferation of human Tenon's capsule fibroblasts

The integrins are protein heterodimers consisting of noncovalently associated alpha and beta subunits. The adhesive interactions mediated by integrins are necessary for cellular survival and proliferation. In this study we investigated the effects of three different integrin antibodies on the proliferation of human Tenon's capsule fibroblasts in tissue culture. Human Tenon's capsule fibroblasts were cultured into 96 well plates and treated with different concentrations (ranging from 10(-6) to 1 microg ml(-1)) of three different integrin antibodies: human integrin alpha-2 antibody, human integrin alpha-3 antibody and human integrin alpha-5/FnR (fibronectin receptor) antibody. Coulter counter, hexosaminidase, and 3H-thymidine assays were used to determine the inhibitory effects of these integrin antibodies on ocular fibroblasts on days 0 (attachment), 1,3 and 7 following antibody treatment. The concentration of each antibody required to produce a proliferation 50% less than the control (ID50) was calculated for each assay. With respect to attachment, all three antibodies studied displayed some inhibitory activity. All three antibodies also displayed dose-dependent antiproliferative properties, especially at the highest concentration tested after 7 days of exposure. The integrin alpha-2 antibody was the most potent of the inhibitors, followed by the integrin alpha-3 antibody, with the integrin alpha-5 antibody being the least potent antibody tested. In addition, the anti-proliferative activities of the integrin alpha-2 and integrin alpha-3 antibodies increased with increasing incubation time. In conclusion, these integrin antibodies demonstrated some inhibitory effects on the attachment and proliferation of human Tenon's capsule fibroblasts in culture. Further investigation will be required to determine whether integrin antibodies can significantly limit scar formation in vivo without significant toxicity.

Confocal analysis of cytoskeletal organisation within isolated chondrocyte sub-populations cultured in agarose

This study reports the cytoskeletal organisation within chondrocytes, isolated from the superficial and deep zones of articular cartilage and seeded into agarose constructs. At day 0, marked organisation of actin microfilaments was not observed in cells from both zones. Partial or clearly organised microtubules and vimentin intermediate filaments cytoskeletal components were present, however, in a proportion of cells. Staining for microtubules and vimentin intermediate filaments was less marked after 1 day in culture however than on initial seeding. For all three cytoskeletal components there was a dramatic increase in organisation between days 3 and 14 and, in general, organisation was greater within deep zone cells. Clear organisation for actin microfilaments was characterised by a cortical network and punctate staining around the periphery of the cell, while microtubules and vimentin intermediate filaments formed an extensive fibrous network. Cytoskeletal organisation within chondrocytes in agarose appears, therefore, to be broadly similar to that described in situ. Variations in the organisation of actin microfilaments between chondrocytes cultured in agarose and in monolayer are consistent with a role in phenotypic modulation. Vimentin intermediate filaments and microtubules form a link between the plasma membrane and the nucleus and may play a role in the mechanotransduction process.

The effectiveness and safety of brimonidine as mono-, combination, or replacement therapy for patients with primary open-angle glaucoma or ocular hypertension: a post hoc analysis of an open-label community trial. Glaucoma Trial Study Group

The purpose of this study was to determine the effectiveness and safety of brimonidine 0.2% (Alphagan, Allergan Inc., Irvine, CA) as mono-, combination, or replacement therapy for reducing intraocular pressure (IOP) in patients with primary open-angle glaucoma or ocular hypertension. The study method was an open-label, comparative clinical evaluation involving 2335 patients. During the 2-month trial, data were collected at baseline (visit 1), month 1 (visit 2), and month 2 (visit 3). Various parameters were evaluated, including glaucoma medications (visit 1), IOP (visit 1-visit 3), and adverse events. A subset cohort of 1254 patients was selected that met specific study criteria. Data from these 1254 patients were used to evaluate adverse events and the change in IOP from visit 1 to visit 3. Patient data were grouped according to specific drug regimen, and drug regimens were categorized into supergroups of mono-, combination, and replacement therapy. The results of the study revealed that the overall mean change in IOP for 1) monotherapy (n = 240) was -5.07 mm Hg (-20.2%), 2) combination therapy (n = 554) was -4.01 mm Hg (-16.9%), 3) replacement therapy (n = 460) was -2.33 mm Hg (-9.8%), and 4) overall (n = 1254) was -3.59 mm Hg (-14.9%) (p < 0.001 for all changes). Overall, 6.0% of the subjects reported adverse events, with no hypersensitivity or unexpected systemic or ocular adverse events. Eighty-five percent (85%) of clinicians rated brimonidine as "good" to "excellent". In conclusion, brimonidine is safe and effectively lowers IOP when used as mono-, combination, or replacement therapy as observed in a large community population.

Chondrocyte deformation within compressed agarose constructs at the cellular and sub-cellular levels

Mechanotransduction events in articular cartilage may be resolved into extracellular components followed by intracellular signalling events, which finally lead to altered cell response. Cell deformation is one of the former components, which has been examined using a model involving bovine chondrocytes seeded in agarose constructs. Viable fluorescent labels and confocal laser scanning microscopy were used to examine cellular and sub-cellular morphology. It was observed that cell size increased up to day 6 in culture, associated with an increase in the contents of proteoglycan and collagen. In addition, the organisation of the cytoskeleton components, described using a simple scoring scale, revealed temporal changes for actin fibres, microtubules and vimentin intermediate filaments. The constructs on day 1 were also subjected to unconfined compressive strains. A series of confocal scans through the centre of individual cells revealed a change from a spherical to an elliptical morphology. This was demonstrated by a change in diameter ratio, from a mean value of 1.00 at 0% strain to 0.60 at 25% strain. Using simple equations, the volume and surface areas were also estimated from the scans. Although the former revealed little change with increasing construct strain, surface area appeared to increase significantly. However further examination, using transmission electron microscopy to reveal fine ultrastructural detail at the cell periphery, suggest that this increase may be due to an unravelling of folds at the cell membrane. Cell deformation was associated with a decrease in the nuclear diameter, in the direction of the applied strain. The resulting nuclear strain in one direction increased in constructs compressed at later time points, although its values at all three assessment times were less than the corresponding values for cell strain. It is suggested that the nuclear behaviour may be a direct result of temporal changes observed in the organisation of the cytoskeleton. The study demonstrated that the chondrocyte-agarose model provides a useful system for the examination of compression events at both cellular and sub-cellular levels.

Efficacy of brimonidine as replacement therapy in patients with open-angle glaucoma or ocular hypertension

BACKGROUND

Patients with glaucoma or ocular hypertension may have inadequately controlled intraocular pressure (IOP) or experience adverse effects with their current medication regimens.

OBJECTIVE

This post hoc reanalysis determined the effectiveness and tolerability of brimonidine used as replacement therapy in a real-life clinical practice setting.

METHODS

In this multicenter, open-label, observational, 2-month study, 460 patients received brimonidine 0.2% as a 1:1 replacement for another antiglaucoma medication in their current regimen. Effectiveness was assessed by calculating the mean additional reduction in IOP from the treated baseline measurement (before the switch to brimonidine) to 2 months postbaseline, and by determining physicians' opinions of treatment effectiveness. Tolerability was determined based on quality-of-life assessments and recorded adverse events.

RESULTS

Overall, brimonidine replacement significantly reduced mean (+/- SEM) IOP by an additional 2.33 +/- 0.17 mm Hg (9.8% +/- 0.9%; P < 0.001). Significant additional reductions in IOP were seen when brimonidine replaced an agent used either as monotherapy or adjunctive therapy, regardless of the drug class of the agent replaced. However, particularly good hypotensive effectiveness and additional lowering of IOP were observed when brimonidine replaced certain medications, including latanoprost (12.44%; P < 0.003) and betaxolol (13.56%; P < 0.001) monotherapy, and latanoprost (16.08%; P < 0.010) adjunctive therapy. The effectiveness of brimonidine was rated as good or excellent by 92.4% of physicians. All quality-of-life variables remained favorable or improved throughout the study, and brimonidine treatment was well tolerated.

CONCLUSIONS

Brimonidine 0.2% used as a 1:1 replacement for monotherapy or adjunctive therapy with other antiglaucoma drugs significantly lowered IOP from that produced by previous therapy and was well tolerated. Brimonidine offers a useful treatment option in patients who require replacement therapy.

Transcriptional repression of the transforming growth factor-beta type I receptor gene by DNA methylation results in the development of TGF-beta resistance in human gastric cancer

The transforming growth factor-beta (TGF-beta) signaling pathway subserves an essential tumor suppressor function in various cell types. A heteromeric complex composed of TGF-beta type I (RI) and type II (RII) receptors is required for TGF-beta signaling. We have identified a subset of human gastric cancer cell lines which are insensitive to TGF-beta and which express a low level of TGF-beta type I receptor mRNA relative to a gastric cancer cell line which is highly responsive to TGF-beta. Using these cells, we show that hypermethylation of a CpG island in the 5' region of the TGF-beta RI gene provides another potentially important mechanism of escape from negative growth control by TGF-beta. This hypermethylation was found in four of five human gastric cancer cell lines and five out of 40 (12.5%) primary tumors examined. In human gastric cancer cell lines, treatment with the demethylating agent, 5-aza-2'-deoxycytidine, resulted in increased expression of the TGF-beta RI gene, but not the RII gene. Transient transfection of an RI expression vector into the TGF-beta resistant SNU-601 cell line restores TGF-beta responsiveness. These findings suggest that one of the mechanisms of escape from autocrine or paracrine growth control by TGF-beta during carcinogenesis could involve aberrant methylation of CpG islands in the 5' region of the TGF-beta RI gene.

Refractive errors and visual acuity impairment among self-selected Hispanic, white, and black adults examined by the UCLA Mobile Eye Clinic

BACKGROUND

Occurrence of refractive errors and uncorrected visual acuity impairment among self-selected, indigent, medically underserved Hispanic, white, and black adults examined by the staff of the UCLA Mobile Eye Clinic (MEC) are described in this study and compared to population-based studies.

METHODS

The study sample consisted of all 2,970 Hispanic, 1,228 white, and 1,028 black participants, for a total of 5,226 self-selected adults, ages 25 to 74 years, who received vision screenings and eye examinations by the staff of the UCLA MEC from 1987 to 1997. Tests consisted of visual acuity, refractive error, intraocular pressure, retinoscopy, slit-lamp biomicroscopy, direct ophthalmoscopic examination, and indirect ophthalmoloscopy with pupillary dilation. Levels of visual acuity impairment were defined as mild (20/50-20/80), moderate (20/100), or severe (20/200 or worse) in either eye.

RESULTS

Self-selected whites in this study had higher rates of astigmatism, anisometropia, and hyperopia, while myopia was higher among self-selected blacks. Myopia and hyperopia occurred more frequently among younger age groups for all ethnic groups. Whites had a higher occurrence of mild, moderate, and severe visual acuity impairment, as compared with Hispanics and blacks.

CONCLUSIONS

Both refractive errors and impaired visual acuity of this self-selected sample are similar to those of adults from the National Health and Nutrition Examination Survey, Hispanic Health and Nutrition Examination Survey, and the Baltimore Eye Survey. The data presented in this study provide a crude estimate of the occurrence of refractive errors and impaired visual acuity among self-selected, medically underserved, indigent Hispanic, white, and black adults in the Los Angeles area.

A population-based survey of hospitalized work-related ocular injury: diagnoses, cause of injury, resource utilization, and hospitalization outcome

Occupational injury is a major source of ocular trauma and is often preventable. A statewide population-based survey of severe work-related ocular injury was generated by using the California Hospital discharge database to identify hospitalized ocular injury and workers compensation as principal payor to identify work-relatedness. Information concerning diagnoses, procedures, causes of injury, length of hospital stay, total hospital charges and disposition at hospital discharge were obtained for injuries occurring during the calendar year 1988. A total of 455 admissions for work-related ocular trauma were identified. The most common work-related ocular trauma diagnoses associated with hospitalizations were open globe injury (46%), adnexal wounds (20%), orbital fractures (11%), and traumatic hyphema (11%). The most common causes of work-related ocular trauma were foreign-body or projectile objects (19%), transport vehicles (18%), cutting or piercing objects (17%), and assaults (9%). Approximately 8% reported other than routine disposition at time of hospital discharge, including long-term nursing or rehabilitation services and death. Mean hospital stay when ocular trauma was the principal admitting diagnosis was 3.7 days. Results differed significantly for admissions reporting ocular trauma as the principal admitting diagnosis compared to admissions that did not. Hospitalized work-related ocular trauma is represented by a wide spectrum of injuries with substantial morbidity and economic costs. Projected to the United States population, these data indicate annual hospital charges excluding professional fees of $14.6 million when work-related ocular trauma is the principal admitting diagnosis and $40 million for admissions where ocular trauma is either a principal or secondary diagnosis.

A validation study for the extraction and analysis of DNA from human nail material and its application to forensic casework

A validation study was conducted to demonstrate that deoxyribonucleic acid (DNA) could be successfully extracted from human nail material and analyzed using short tandem repeat (STR) profiling and/or mitochondrial DNA (mtDNA) sequencing. This study involved the development of a DNA extraction protocol that includes a cleaning procedure designed to remove external contaminants (e.g., biological, chemical). This protocol was used to test human nail material that had been soaked in whole blood from a second donor and coated with gold-palladium to simulate scanning electron microscopic analysis. The results showed no indication of a mixture and were consistent with that of the nail donor. Fresh human nail material usually yielded both STR profiles and mtDNA sequence information; however, aged human nail material (approximately eight years old) yielded only mtDNA sequence information. Upon completion of the validation study, the extraction protocol was used for the analysis of a torn fingernail fragment recovered from the scene of a violent homicide in 1983. A partial STR profile and mtDNA sequence information indicated that the fingernail fragment was excluded as originating from the suspect and was, in fact, consistent with originating from one of the victims.

The effectiveness and safety of dorzolamide 2% in addition to multiple topical antiglaucoma medications

Dorzolamide is the first commercial topical carbonic anhydrase inhibitor approved by the Food and Drug Administration (FDA) for the treatment of glaucoma. In a prospective, open label, uncontrolled study on 245 glaucoma patients, dorzolamide significantly lowered the intraocular pressure at least 14% when used alone or in combination with one, two, or three other antiglaucoma medications over ten weeks. There were very few adverse reactions to dorzolamide. Dorzolamide is effective and safe when used alone or in combination with other topical antiglaucoma medications for the treatment of glaucoma.

Vision screening of abused and neglected children by the UCLA Mobile Eye Clinic

BACKGROUND

The purpose of our study was to present descriptive findings of ocular abnormalities in vision screening examinations of abused and neglected children. We compared the prevalence and the nature of eye diseases and refractive error between abused and neglected boys staying at the Hathaway Home, a residential facility for abused children, and boys from neighboring Boys and Girls clubs.

METHODS

The children in the study received vision screening examinations through the UCLA Mobile Eye Clinic following a standard format. Clinical data were analyzed by chi-square test.

RESULTS

The children with a history of abuse demonstrated significantly higher prevalence of myopia, astigmatism, and external eye disorders.

CONCLUSIONS

Our study suggests that children with a history of abuse may be at higher risk for visual impairment. These visual impairments may be the long-term sequelae of child abuse.

Latanoprost in glaucoma associated with Sturge-Weber syndrome: benefits and side-effects

PURPOSE

This study was conducted to evaluate the ocular hypotensive efficacy, safety, and side effects of latanoprost 0.005% administered as adjunctive therapy in patients with Sturge-Weber syndrome (SWS) and glaucoma.

METHODS

Commercially available latanoprost 0.005% was added as a single drop once daily to other antiglaucoma medications. Intraocular pressure (IOP) was measured at 1, 3, and 6 months of treatment. A successful response was defined as a reduction of at least 20% in IOP at the final follow-up evaluation without additional medical or surgical therapy and no adverse events related to latanoprost.

RESULTS

18 eyes of 18 patients with SWS and glaucoma were enrolled from 9 clinical centers. Mean baseline IOP was 28.4 +/- 7.1 mmHg (range, 17-42 mmHg). Using Kaplan-Meier analysis, a successful response to latanoprost was observed in 3 of 18 (16.7%) patients at the 6-month interval. Seven (38.9%) patients required surgery; three (16.7%) patients required additional medical therapy, seven (38.9%) patients had no change in therapy. One (5.6%) patient discontinued latanoprost treatment because of intolerable conjunctival hyperemia. Two successfully treated patients had significantly greater episcleral vessel engorgement after initiation of latanoprost therapy.

CONCLUSION

Patients with SWS and glaucoma respond poorly to adjunctive latanoprost therapy and often require additional medical or surgical intervention. Increased episcleral vascular engorgement might result in greater operative risks should filtration surgery become necessary in these patients.

Measurement of the deformation of isolated chondrocytes in agarose subjected to cyclic compression

Mechanically induced cell deformation is one of a number of possible mechanotransduction pathways by which chondrocytes sense and respond to changes in their mechanical environment. The present study describes a system for measuring the deformation of isolated chondrocytes in agarose during both static and cyclic compression. A test rig mounted on the stage of an inverted microscope was used to apply precise levels of compressive strain to individual cell-agarose constructs bathed in culture medium. Images of the cells were recorded using a CCD video camera attached to the microscope. Cell deformation was quantified in terms of a deformation index (X/Y) representing the ratio of cell diameters measured parallel (X) and perpendicular (Y) to the axis of compression. Cyclic compression between 0 and 15% strain, at 0.3 Hz, resulted in cyclic deformation of the cells at the same frequency. However, during the unstrained phase the cells did not fully recover to their initially spherical morphology (X/Y = 1.0). During the strained phase, the level of deformation (X/Y = 0.59) was initially similar to that observed during static 15% strain. However, this level of cell deformation reduced over a 20 min period of cyclic compression (X/Y = 0.72), although during static compression the cell deformation remained constant. This system may be used to examine cellular events under a range of dynamic mechanical stimuli.

Lymphomas in solid organ transplantation

BACKGROUND

The purpose of this investigation was to identify and characterize abdominal lymphomas as they occur in a large solid-organ-transplant population.

METHODS

A large transplant population was isolated, and all patients developing an abdominal lymphoma were identified. These patients were further characterized after review of their medical records and radiologic examinations.

RESULTS

Twenty-eight (1%) of 2925 patients developed lymphoma following transplantation. Of these 28 patients, 14 developed abdominal manifestations of disease. Examples of the wide variety of abdominal manifestations of posttransplant lymphoma are presented. Most of these patients had positive titers for Epstein-Barr virus and were treated with cyclosporin as a part of their immunotherapy. The majority of patients died secondary to this aggressive disease process.

CONCLUSION

The development of lymphoma following solid organ transplantation is more common than in the general population. One-half of the patients in our study population developed abdominal manifestations of this disease.

Response of chondrocyte subpopulations cultured within unloaded and loaded agarose

Although it is well known that the metabolism of chondrocytes can be altered by the application of mechanical strain, it is unclear whether chondrocytes from the superficial and deep zones of cartilage respond in a similar manner. In this study, chondrocytes from the uppermost 15-20% (superficial cells) and the remaining tissue (deep cells) from bovine articular cartilage were isolated separately and cultured in agarose constructs. Cell deformation on application of a 15% static compressive strain was identical for both subpopulations after 24 and 72 hours in culture. The constructs were incubated under static and dynamic (0.3, 1, and 3 Hz) strains of 15% amplitude. Glycosaminoglycan synthesis by deep cells was unaffected by static strain or 3 Hz dynamic strain, whereas 0.3 Hz produced a significant reduction and 1 Hz induced a highly significant 50% stimulation of glycosaminoglycan synthesis (p < 0.001). Superficial cells exhibited a general inhibition of glycosaminoglycan synthesis. By contrast, proliferation of superficial cells was stimulated by dynamic strain whereas deep cells were not influenced. It has been suggested previously that mechanotransduction-induced controls of glycosaminoglycan synthesis and proliferation in chondrocytes embedded in agarose are uncoupled. Data presented in this study demonstrate that the two processes do, in fact, occur in different subpopulations of chondrocytes within the full-depth cell isolate.

The influence of elaborated pericellular matrix on the deformation of isolated articular chondrocytes cultured in agarose

This study investigates the mechanical influence of pericellular matrix on the deformation of isolated articular chondrocytes compressed within 3% agarose specimens. After 1 day in culture, the cells were associated with minimal amounts of sulphated glycosaminoglycan (GAG) and hydroxyproline and exhibited substantial deformation from a spherical to an oblate ellipsoid morphology when subjected to 20% gross compressive strain. However, over the 6 day culture period, there was a reduction in cell deformation associated with an increase in matrix content. Treatment with testicular hyaluronidase at days 3 and 6 reduced sulphated GAG content to levels observed in untreated specimens at day 1. At day 3, the resulting cell deformation during 20% compression was equivalent to that in specimens compressed at day 1. However, at day 6 cell deformation was only partially restored, suggesting the presence of additional structural matrix components, other than sulphated GAG, which were not present at day 3. Dual scanning confocal microscopy indicated that the elaborated matrix formed a pericellular shell which did not deform during compression and was therefore stiffer than the 3% agarose substrate. Therefore, the elaboration of a mechanically functional pericellular matrix within 6 days, effectively limits the potential involvement of cell deformation in mechanotransduction within cell seeded systems such as those employed for cartilage repair.

Dynamic mechanical compression influences nitric oxide production by articular chondrocytes seeded in agarose

Nitric oxide (NO) has been implicated in the inhibition of cell proliferation in cytokine and lipopolysaccharide (LPS)-stimulated chondrocytes and is known to be influenced by physical forces in several tissues. In this study, a well-characterized model system utilizing bovine chondrocytes embedded in 3% agarose constructs has been used to investigate the effect of dynamic strain at 0.3, 1, or 3 Hz on NO production. LPS induced a significant increase in nitrite levels, which was reversed by both L-NAME and dexamethasone. Dynamic compressive strain produced a significant reduction in nitrite production. The effect was partially blocked by L-NAME but unaffected by dexamethasone. L-NAME also reversed dynamic compression-induced stimulation of [3H]-thymidine incorporation. NO appears to be a constituent of mechanotransduction pathways which influence proliferation of bovine chondrocytes seeded within agarose constructs. The inhibitor experiments also infer that alterations in cNOS activity primarily determine the response.