The protein disulfide isomerases PDIA4 and PDIA6 mediate resistance to cisplatin-induced cell death in lung adenocarcinoma.

Intrinsic and acquired chemoresistance are frequent causes of cancer eradication failure. Thus, long-term cis-diaminedichloroplatine(II) (CDDP) or cisplatin treatment is known to promote tumor cell resistance to apoptosis induction via multiple mechanisms involving gene expression modulation of oncogenes, tumor suppressors and blockade of pro-apoptotic mitochondrial membrane permeabilization. Here, we demonstrate that CDDP-resistant non-small lung cancer cells undergo profound remodeling of their endoplasmic reticulum (ER) proteome (>80 proteins identified by proteomics) and exhibit a dramatic overexpression of two protein disulfide isomerases, PDIA4 and PDIA6, without any alteration in ER-cytosol Ca(2+) fluxes. Using pharmacological and genetic inhibition, we show that inactivation of both proteins directly stimulates CDDP-induced cell death by different cellular signaling pathways. PDIA4 inactivation restores a classical mitochondrial apoptosis pathway, while knockdown of PDIA6 favors a non-canonical cell death pathway sharing some necroptosis features. Overexpression of both proteins has also been found in lung adenocarcinoma patients, suggesting a clinical importance of these proteins in chemoresistance.

Imaging apoptosis in the eye.

Apoptosis is a form of programmed cell death that is implicated in both pathological and physiological processes throughout the body. Its imaging in vivo with intravenous radiolabelled-annexin V has been heralded as an important advance, with around 30 clinical trials demonstrating its application in the early detection and monitoring of disease, and the assessment of efficacy of potential and existing therapies. A recent development has been the use of fluorescently labeled annexin V to visualize single retinal cells undergoing the process of apoptosis in vivo with ophthalmoscopy. This has been given the acronym DARC (Detection of Apoptosing Retinal Cells). DARC so far has only been used experimentally, but clinical trials are starting shortly in glaucoma patients. Results suggest that DARC may provide a direct assessment of retinal ganglion cell health. By enabling early assessment and quantitative analysis of cellular degeneration in glaucoma, it is hoped that DARC can identify patients before the onset of irreversible vision loss. Furthermore, in addition to aiding the tracking of disease, it may provide a rapid and objective assessment of potential and effective therapies, providing a new and meaningful clinical endpoint in glaucomatous disease that is so badly needed.

Responsiveness of human monocyte-derived dendritic cells to thimerosal and mercury derivatives.

Several cases of skin sensitization have been reported following the application of thimerosal, which is composed of ethyl mercury and thiosalicylic acid (TSA). However, few in vitro studies have been carried out on human dendritic cells (DCs) which play an essential role in the initiation of allergic contact dermatitis. The aim of the present study was to identify the effect of thimerosal and other mercury compounds on human DCs. To address this purpose, DCs derived from monocytes (mono-DCs) were used. Data show that thimerosal and mercury derivatives induced DC activation, as monitored by CD86 and HLA-DR overexpression associated with the secretion of tumor necrosis factor alpha and interleukin 8, similarly to lipopolysaccharide and the sensitizers, 1-chloro-2,4-dinitrobenzene (DNCB) and nickel sulfate, which were used as positive controls. In contrast, TSA, the non-mercury part of thimerosal, as well as dichloronitrobenzene, a DNCB negative control, and the irritant, sodium dodecyl sulfate, had no effect. Moreover, oxidative stress, monitored by ROS induction and depolarization of the mitochondrial membrane potential, was induced by thimerosal and mercury compounds, as well as DNCB, in comparison with hydrogen peroxide, used as a positive control. The role of thiol oxidation in the initiation of mono-DC activation was confirmed by a pre-treatment with N-acetyl-l-cysteine which strongly decreased chemical-induced CD86 overexpression. These data are in agreement with several clinical observations of the high relevance of thimerosal in patch-test reactions and prove that human mono-DCs are useful in vitro tools for determining the allergenic potency of chemicals.

Single intraoperative application of 5-Fluorouracil versus placebo in low-risk trabeculectomy surgery: a randomized trial.

PURPOSE: Trabeculectomy is the procedure of choice for the surgical control of glaucoma, and is often augmented by intraoperative 5-fluorouracil application to reduce scarring. This study aims to assess the validity of this technique with a randomized placebo-controlled trial. METHODS: Patients without risk factors for bleb failure other than previous drop use who were undergoing trabeculectomy surgery as their first ocular procedure were randomized to receive fluorouracil or placebo. The main outcome measures were intraocular pressure and bleb morphology. RESULTS: Results from 40 eyes of 36 patients are presented; 23 eyes were treated with fluorouracil, and 17 eyes were treated with placebo. Mean intraocular pressure at 1 year and at the final follow-up examination was significantly lower than preoperatively, but was not different between fluorouracil and placebo groups. Kaplan-Meier survival analysis also failed to show any difference, though there was a trend toward better survival of an intraocular pressure of 16 mm Hg or lower. Bleb morphology was examined postoperatively in 24 patients, with no differences found between fluorouracil and placebo groups. CONCLUSIONS: No significant difference was found in trabeculectomy outcome between fluorouracil-treated and placebo-treated eyes. The study was too small to state definitively that no such difference exists, but suggests that any treatment effect is likely to be small.

Prescription of eye drops.

The aim of this study was to assess whether patients have their ocular drops correctly prescribed during non-ophthalmic admissions to hospital. A retrospective review of notes of patients who were admitted to hospital for general medical or surgical care, while on regular eye drops at the time of admission was performed. Twenty two patients were on regular ocular medication when admitted. Only seven out of 22 patients had their eye drops correctly prescribed. Furthermore, six patients had been prescribed topical beta-blockers, yet suffered from medical conditions that may have been aggravated by these drops. These findings demonstrate that the majority of patients on drops do not have their medication correctly prescribed during non-ophthalmic admissions to hospital. Also topical beta-blockers continue to be inappropriately prescribed.

Glaucoma medical treatment: philosophy, principles and practice.

There have been numerous recent advances in the management of glaucoma, not least the development of new drugs to help manage raised intraocular pressure. In addition, the concepts of improving blood flow to the optic nerve head and neuroprotection are currently provoking considerable interest. This article considers the aims and philosophy of glaucoma drug therapy, summarises some of the basic facts and principles of modern glaucoma medications, and suggests a practical approach to the choice of therapy.

Spatial and temporal visual filtering in patients with glaucoma and ocular hypertension.

PURPOSE: To investigate the spatial and temporal response characteristics in patients with glaucoma and ocular hypertension (OHT), in order to demonstrate the earliest specific measure of vision loss and to elucidate the precise mechanism of early glaucomatous damage. METHODS: The Open Optical View System was used to assess changes in spatial and temporal vision in patients with clearly defined glaucoma (30 eyes), patients with OHT (30 eyes) and 30 eye-matched normal control eyes. The psychophysical methods applied were developed by Barber and Ruddock, who showed that the responses called ST1 and ST2 have similar characteristics to those found in the parvocellular and magnocellular pathway respectively. The measurement of spatial and temporal responses rests upon the measurement of a target that moves across a background, itself modulated spatially (gratings) and temporally (flicker). RESULTS: The results reported, taken together with the current data on retinal ganglion cell function, reveal damage to both the parvocellular and magnocellular pathway in patients with glaucoma. In the OHT groups only marginal changes were found in the parvocellular response, but significant changes in the magnocellular response. In both OHT and glaucoma, the temporal processing shows greatest abnormalities at a small number of low flicker frequencies. CONCLUSION: We provide psychophysical evidence of the detectable ganglion cell damage in patients with OHT who remain normal on testing with automated perimetry. The psychophysical method chosen (which measures the function of specific sub-divisions of the visual pathway) may prove useful in screening for glaucomatous damage.

Effect of brimonidine tartrate on ocular hemodynamic measurements.

OBJECTIVE: To study the effect of a selective alpha 2-adrenoreceptor agonist, brimonidine tartrate, on ocular hemodynamics. SUBJECTS AND METHODS: Eighteen patients with ocular hypertension were enrolled in a prospective, randomized, double-masked study in which 0.2% brimonidine tartrate, administered twice daily, was compared with its vehicle in a crossover fashion. The effect on the ocular circulation was assessed by color Doppler ultrasound, which measured blood flow velocities (peak systolic and end diastolic velocities) in the central retinal, ophthalmic, nasal, and temporal ciliary arteries. The following tests were performed at 2 weekly intervals on both treatments, 0.2% brimonidine tartrate and the placebo: intraocular pressure, heart rate, blood pressure, and color Doppler ultrasound. RESULTS: Velocities and resistivity indices measured by color Doppler ultrasound in the ophthalmic artery, central retinal artery, nasal artery, and temporal ciliary arteries showed no statistically significant differences between the placebo and 0.2% brimonidine tartrate when compared with baseline values and between the groups. Intraocular pressure was decreased by 17.7% +/- 9.5% with 0.2% brimonidine tartrate (vs 9% +/- 8% with placebo). CONCLUSION: The hemodynamics of the posterior segment of the eye as measured by color Doppler ultrasound do not appear to be altered by 2% brimonidine tartrate.

Brain natriuretic peptide: identification of a second natriuretic peptide in human aqueous humour.

AIMS/BACKGROUND: To measure aqueous humour levels of brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP) in humans. To compare peptide levels in glaucomatous and control eyes to test the hypothesis that these peptides are increased in glaucoma. BNP and ANP are cyclic endopeptides whose principal biological effects are natriuresis and vasodilatation. Experimental glaucoma in animal models results in elevated aqueous ANP. Intravenous ANP administration in both animals and humans causes lowering of intraocular pressure (IOP). There are equivocal data to support a role for ANP in IOP regulation in human eyes. There are as yet no published data on BNP in human aqueous humour. METHOD: This was a case-control study. Cases were primary open angle, pseudoexfoliation, and mixed mechanism glaucoma eyes undergoing trabeculectomy. Controls were cataract extraction eyes. There were 47 trabeculectomy eyes (44 patients) and 47 cataract extraction eyes (46 patients) matched for age, sex, race, systemic medications, and type of anaesthetic. 100-200 microliters of aqueous humour were aspirated by paracentesis as the first step in the surgical procedure. Peptide levels were later measured by radioimmunoassay. RESULTS: The presence of BNP and ANP in human aqueous humour was confirmed. BNP was present in higher concentrations than ANP. BNP levels tended to be greater in control eyes--glaucoma median 56.5 (range 0-3526.5) pg/ml versus control median 65.16 (range 0-1788) pg/ml (Wilcoxon signed rank test p = 0.78). ANP levels tended to be greater in glaucoma eyes than in controls: glaucoma median 3 (range 0-68.5) pg/ml versus control median 0 (range 0-60) pg/ml (Wilcoxon signed rank test p = 0.82). ANP and BNP were log linearly related in both groups (r glaucoma group = 0.961, r control group = 0.894). CONCLUSION: This is the first report of BNP and ANP in human aqueous humour. Peptide levels did not differ significantly between glaucoma and cataract extraction eyes. A linear relation between log BNP and ANP was found. Further studies are required to clarify the role of these peptides in aqueous humour production and IOP regulation.

Trabeculectomy with intraoperative sponge 5-fluorouracil in Afro-Caribbeans.

AIM: To study the efficacy and safety of intraoperative 5-fluorouracil (5-FU) in Afro-Caribbean patients. METHODS: The results of trabeculectomy in 18 eyes of 18 Afro-Caribbean patients in whom a sponge soaked in 25 mg/ml solution of 5-FU was applied between Tenon's capsule and sclera for 5 minutes before excision of the trabecula were compared with 16 eyes of 16 Afro-Caribbean patients matched for age, quantity, and duration of preoperative medications, who underwent trabeculectomy without 5-FU. RESULTS: The mean postoperative intraocular pressure (IOP) at 1 month was 15.6 (SD 6.1) mm Hg in the 5-FU group and 18.0 (5.2) mm Hg in the control group (p = 0.15). There was no significant difference in the IOP at 6, 12, 15, 18, and 24 months in the two groups. Success rate at 18 months defined as an IOP less than or equal to 21 mm Hg with no adjunctive medication was 56% in the 5-FU group and 55% in the control group. No major complications were noted in either group. CONCLUSION: Intraoperative sponge 5-FU alone is safe but does not appear to decrease the risk of failure of trabeculectomy in Afro-Caribbeans.

Funduscopy versus photographic assessment of cytomegalovirus retinitis progression: a clinician's perspective.

OBJECTIVE: Funduscopy was compared with retinal photographs in the documentation of progression of cytomegalovirus (CMV) retinitis. SETTING: Clinical centres provided oral ganciclovir maintenance therapy for AIDS patients with CMV retinitis inaccurately involved in randomized trials of oral versus intravenous ganciclovir for maintenance therapy of patients with newly diagnosed or previously treated CMV retinitis, in North America, Europe and Australia. DESIGN: Serial retinal photographs and funduscopy examinations were conducted at each patient visit in order to detect progression of CMV retinitis during the course of oral ganciclovir maintenance therapy. CONCLUSIONS: Retinal photography is the most accurate for central lesions, funduscopy is preferable for diffuse and peripheral lesions, and in the day-to-day management of patients, the combined approach provides the most accurate information.

Current techniques in wound healing modulation in glaucoma surgery.

The wound healing response is the single most important determinant of the final intraocular pressure after glaucoma surgery. The use of antiscarring agents, particularly the antimetabolites 5-fluorouracil and mitomycin C, have revolutionized glaucoma surgery over the past decade. This subject has become more important with the realization that simply lowering the intraocular pressure to below 21 mm Hg is inadequate, and that optimal lowering of the intraocular pressure should be achieved in all patients undergoing surgery for glaucoma. However, the antimetabolites still have many potential problems and side effects, some of which are potentially sightthreatening. This review concentrates on the recent publications in this field that have determined the current "state of the art," with a view toward optimizing results and minimizing side effects for our patients with glaucoma in this exciting and challenging area of progress.

Screening for cytomegalovirus retinitis in HIV-positive and AIDS patients.

The ability of physicians to screen for AIDS-related cytomegalovirus retinitis (CMVR) was studied at a London AIDS centre. Patients had undergone direct ophthalmoscopy as part of their general examination by the physicians and were referred if fundal abnormalities were found, if a focus of extra-ocular CMVR was present or if the patient complained of visual symptoms. The provisional diagnoses of the physicians were compared with the final diagnoses of the ophthalmologists. Of 348 consecutive patients referred for an ophthalmic opinion, the physicians made the correct diagnosis in 69% of those referred with a provisional diagnosis of CMVR, in 66% of those with normal fundi and in 81% of those with toxoplasma chorioretinitis. Those cases of CMVR which were misdiagnosed by the physicians were usually mistaken for other retinal pathology which would warrant a specialist referral. Screening for CMVR in HIV-positive and AIDS patients may safely be undertaken by physicians familiar with the ocular manifestations of HIV-related disease.