PlGF-1 and VEGFR-1 pathway regulation of the external epithelial hemato-ocular barrier. A model for retinal edema.

VEGF is considered as an important factor in the pathogenesis of macular edema. VEGF induces the rupture of the blood retinal barrier and may also influence the retinal pigment epithelial (RPE) outer retinal barrier. The aim of this work was to analyze the influence of the VEGF receptor pathways in the modulation of the RPE barrier breakdown in vitro and in vivo. The ARPE19 human junctions in culture are modulated by VEGF through VEGFR-1 but not through VEGFR-2. PlGF-1, that is a pure agonist of VEGFR-1, is produced in ARPE-19 cells under hypoxic conditions and mimics VEGF effects on the external retinal barrier as measured by TER and inulin flux. In vivo, the intravitreous injection of PlGF-1 induces a rupture of the external retinal barrier together with a retinal edema. This effect is reversible within 4 days. VEGF-E, that is a pure agonist of VEGFR-2, does not induce any acute effect on the RPE barrier. These results demonstrate that PlGF-1 can reproduce alterations of the RPE barrier occurring during diabetic retinopathy.

Intra-arterial hepatic fotemustine for the treatment of liver metastases from uveal melanoma: experience in 101 patients.

BACKGROUND: Exclusive liver metastases occur in up to 40% of patients with uveal melanoma associated with a median survival of 2-7 months. Single agent response rates with commonly available chemotherapy are below 10%. We have investigated the use of fotemustine via direct intra-arterial hepatic (i.a.h.) administration in patients with uveal melanoma metastases. PATIENTS AND METHODS: A total of 101 patients from seven centers were treated with i.a.h. fotemustine, administered intra-arterially weekly for a 4-week induction period, and then as a maintenance treatment every 3 weeks until disease progression, unacceptable toxicity or patient refusal. RESULTS: A median of eight fotemustine infusions per patient were delivered (range 1-26). Catheter related complications occurred in 23% of patients; however, this required treatment discontinuation in only 10% of the patients. The overall response rate was 36% with a median overall survival of 15 months and a 2-year survival rate of 29%. LDH, time between diagnosis and treatment start and gender were significant predictors of survival. CONCLUSIONS: Locoregional treatment with fotemustine is well tolerated and seems to improve outcome of this poor prognosis patient population. Median survival rates are among the longest reported and one-third of the patients are still alive at 2 years.

Oligopotent stem cells are distributed throughout the mammalian ocular surface.

The integrity of the cornea, the most anterior part of the eye, is indispensable for vision. Forty-five million individuals worldwide are bilaterally blind and another 135 million have severely impaired vision in both eyes because of loss of corneal transparency; treatments range from local medications to corneal transplants, and more recently to stem cell therapy. The corneal epithelium is a squamous epithelium that is constantly renewing, with a vertical turnover of 7 to 14 days in many mammals. Identification of slow cycling cells (label-retaining cells) in the limbus of the mouse has led to the notion that the limbus is the niche for the stem cells responsible for the long-term renewal of the cornea; hence, the corneal epithelium is supposedly renewed by cells generated at and migrating from the limbus, in marked opposition to other squamous epithelia in which each resident stem cell has in charge a limited area of epithelium. Here we show that the corneal epithelium of the mouse can be serially transplanted, is self-maintained and contains oligopotent stem cells with the capacity to generate goblet cells if provided with a conjunctival environment. Furthermore, the entire ocular surface of the pig, including the cornea, contains oligopotent stem cells (holoclones) with the capacity to generate individual colonies of corneal and conjunctival cells. Therefore, the limbus is not the only niche for corneal stem cells and corneal renewal is not different from other squamous epithelia. We propose a model that unifies our observations with the literature and explains why the limbal region is enriched in stem cells.

Intraocular penetration of penciclovir after oral administration of famciclovir: a population pharmacokinetic model.

OBJECTIVES: We developed a population model that describes the ocular penetration and pharmacokinetics of penciclovir in human aqueous humour and plasma after oral administration of famciclovir. METHODS: Fifty-three patients undergoing cataract surgery received a single oral dose of 500 mg of famciclovir prior to surgery. Concentrations of penciclovir in both plasma and aqueous humour were measured by HPLC with fluorescence detection. Concentrations in plasma and aqueous humour were fitted using a two-compartment model (NONMEM software). Inter-individual and intra-individual variabilities were quantified and the influence of demographics and physiopathological and environmental variables on penciclovir pharmacokinetics was explored. RESULTS: Drug concentrations were fitted using a two-compartment, open model with first-order transfer rates between plasma and aqueous humour compartments. Among tested covariates, creatinine clearance, co-intake of angiotensin-converting enzyme inhibitors and body weight significantly influenced penciclovir pharmacokinetics. Plasma clearance was 22.8 ± 9.1 L/h and clearance from the aqueous humour was 8.2 × 10(-5) L/h. AUCs were 25.4 ± 10.2 and 6.6 ± 1.8 μg · h/mL in plasma and aqueous humour, respectively, yielding a penetration ratio of 0.28 ± 0.06. Simulated concentrations in the aqueous humour after administration of 500 mg of famciclovir three times daily were in the range of values required for 50% growth inhibition of non-resistant strains of the herpes zoster virus family. CONCLUSIONS: Plasma and aqueous penciclovir concentrations showed significant variability that could only be partially explained by renal function, body weight and comedication. Concentrations in the aqueous humour were much lower than in plasma, suggesting that factors in the blood-aqueous humour barrier might prevent its ocular penetration or that redistribution occurs in other ocular compartments.

Fluconazole prophylaxis prevents intra-abdominal candidiasis in high-risk surgical patients.

OBJECTIVE: To evaluate the efficacy and safety of intravenous fluconazole for the prevention of intra-abdominal Candida infections in high-risk surgical patients. DESIGN: Randomized, prospective, double-blind, placebo-controlled study. SETTING: Two university-affiliated hospitals in Switzerland. PATIENTS: Forty-nine surgical patients with recurrent gastrointestinal perforations or anastomotic leakages. INTERVENTIONS: Prophylaxis with intravenous fluconazole (400 mg per day) or placebo continued until resolution of the underlying surgical condition. MEASUREMENTS AND MAIN RESULTS: Patients were evaluated daily, and specimens for culture were obtained three times per week during prophylaxis. The primary study end points were the frequency of and the time to intra-abdominal Candida infections. Secondary end points were the frequency of candidiasis (intra-abdominal and extra-abdominal) and the emergence or persistence of Candida colonization. Among patients who were not colonized at study entry, Candida was isolated from surveillance cultures during prophylaxis in 15% of the patients in the fluconazole group and in 62% of the patients in the placebo group (relative risk, 0.25; 95% confidence interval, 0.07 to 0.96; p = .04). Candida peritonitis occurred in one of 23 patients (4%) who received fluconazole and in seven of 20 patients (35%) who received placebo (relative risk, 0.12; 95% confidence interval, 0.02 to 0.93; p = .02). In addition, one catheter-related Candida albicans sepsis occurred in a fluconazole-treated patient. Thus, overall, candidiasis developed in two fluconazole patients and seven placebo patients (relative risk, 0.25; 95% confidence interval, 0.06 to 1.06; p = .06). C. albicans accounted for 87% of the Candida species isolated before or during prophylaxis, and all C. albicans strains were susceptible to fluconazole. Fluconazole was well tolerated, and adverse events occurred at similar frequencies in both treatment groups. CONCLUSIONS: Fluconazole prophylaxis prevents colonization and invasive intra-abdominal Candida infections in high-risk surgical patients.

Growth arrest-specific gene 6 » (Gas6) as an intra-hospital mortality predictor for patients in septic shock

Aim: Gas6 is known to be elevated in sepsis, correlating with the severity of infection and¦organ failure. We aimed to investigate the performance of Gas6 plasma levels at¦admission to predict the risk of mortality in a cohort of septic patients.¦Methods: We used prospectively collected data and plasma samples from the "Sepsis¦Cohorte Romande". Gas6 level was measured by ELISA at admission and expressed in¦percentage relative to its level in a pool of normal plasma.¦Results: Non-survivors (n=21) presented higher Gas6 levels than survivors (n=73) (median¦258% vs 164%, IQR 194 and 117 respectively) (p=0.0027). Gas6 correlated positively with¦different cytokines and was the best mortality predictor, as shown by the ROC curves area.¦In patients with septic shock (n=66), using 249% as a cut-off value, Gas6 measurement¦had a specificity of 67% and a sensitivity of 81% for predicting mortality. ROC curve area¦was 0.75. Positive and negative predictive values were 57% and 87%, respectively.¦Conclusion: Thus, Gas6 plasma level at admission might be a useful tool to predict¦mortality in patients with septic shock. Although Gas6 hold promise as an early sepsis¦marker, its precise implication in sepsis remains to be elucidated. Our observation should¦be further investigated in larger prospective clinical trials.

Lésions endothéliales des ballons de contre-pulsion intra-aortique [Endothelial lesions caused by intra-aortic counterpulsation balloons]

Intra-aortic balloon pump (IABP) is the most frequently used mechanical circulatory support. Repeated trauma on the aortic wall has been reported as a cause of balloon perforation by endothelial denudation of atheromatous plaque. This study analyses the effect of IABP on the endothelium of the calf aorta. In 12 calves (mean weight: 72 +/- 6 kg) an IABP was inserted by femoral route and left during 6 hours on internal mode with a frequency of 80 cycles/min. The animals were sacrificed after the procedure (n = 4), at postoperative day (POD) 7 (n = 4), and at POD 14 (n = 4). In the aorta facing the balloon, nine transmural samples were taken proximally (n = 3), at mid height (n = 3) and distally (n = 3), for histological analysis of the percentage of aortic surface covered with endothelium. The percentage of aortic surface covered with endothelium at POD 0, 7 and 14 was proximally: 72.5 +/- 27.5%, 83.7 +/- 16.9% and 93.3 +/- 8.9% respectively; at mid-height: 50.8 +/- 30.7%, 65 +/- 25% and 95 +/- 5%; and distally: 31.4 +/- 20.1%, 48.3 +/- 34.4% and 85 +/- 10%. A large portion of the aortic endothelium is abraded after 6 hours of IAB pumping. This effect is more important at the distal level of the aorta. After two weeks, most of the endothelium has regenerated.

Intravitreal ranibizumab for age-related macular degeneration : optical coherence tomography guided retreatment intervals and their intra- and inter-individual variability

Purpose: To determine whether the need for retreatment after an initial phase of 3 monthly intravitreal injections of ranibizumab shows an intra-individual regular rhythm and to what degree it varies between different patients. Methods: Prospective study with 42 patients with exudative AMD, treatment naïve. Loading dose of 3 monthly doses of ranibizumab (0,5 mg), followed by a 12 months pro re nata (PRN) regimen according to early exudative signs on HD-OCT Cirrus, Zeiss. The follow-up visits were intensified (week 4, 5, 6, 7, 8, 10, 12, 14, 16, 20, etc after each injection) in order to detect recurrences early, and injection followed within 3 days in cases of subretinal fluid, cysts, or central thickness increase of>50microns. Intervals were calculated between injections for the 12 month follow-up with PRN treatment. Variability was expressed as standard deviation (SD). Results: Visual acuity (VA) improved from a mean ETDRS score of 61.6 (SD 10.8) at baseline to 68.0 (SD 10.2) at month 3 and to 74.7(SD 9.0) at month 12. The 15 patients who have already completed the study showed maintenance of the VA improvement. Central foveal thickness improved from a mean value of 366 microns (baseline) to 253 microns (month 3), well maintained thereafter. Mean number of injections was 8.8 (SD 3.5,range 0-12) per 12 months of follow-up (after 3 doses), with mean individual treatment-recurrence (TR) intervals ranging from 28->365 days (mean 58). Intraindividual variability of TR intervals (SD) was 7.1 days as a mean value (range 1.7¡V22.6). It ranged within 20% of the mean intra-individual interval for 30 (91%) and within 15% for 21 patients (64%). The first interval was within 1 week of the mean intra-individual interval in 64% and within 2 weeks in 89% of patients. Conclusions: The majority of AMD patients showed a relatively stable rhythm for PRN injections of ranibizumab after initial loading phase, associated with excellent functional/anatomical results. The initial interval last loading dose-first recurrence may have a predictive value for further need of treatment, potentially facilitating follow-up and patient care.

Intra-individual stability of neuromotor tasks from 6 to 18 years: a longitudinal study.

This study investigates the intra-individual stability of the speed of several motor tasks and the intensity of associated movements in 256 children (131 girls, 125 boys) from the Zurich generational study using the Zurich neuromotor assessment battery (ZNA) over a 12-year period from the age of 6 to 18 years. The stability was assessed by correlograms of standard deviation scores calculated from age- and gender-adjusted normative values and compared with standing height and full scale intelligence quotient (IQ). While motor tasks of hand, finger and foot (HFT) and contralateral associated movements (CAM) exhibited a moderate stability (summary measure as correlation coefficients between two measurements made 4 years apart: .61 and .60), other tasks (dynamic balance, static balance and pegboard) were only weakly stable (.46, .47 and .49). IQ and height were more stable than neuromotor components (.72 and .86). We conclude that the moderately stable HFT and CAM may reflect "motor traits", while the stability of the pegboard and balance tasks is weaker because these skills are more experience related and state-dependent.

Inter- and intra-individual variation of oxytocin secretion in oestrous mares exposed to stallions

The neuro-peptide hormone oxytocin regulates several reproductive mechanisms in mammals, such as uterine contractions during parturition and milk ejection in the lactating mammary gland. Oxytocin may also influence behavior and behavioral strategies, e.g. pair bonding, social recognition, maternal behavior, trust building, or anxiety. Teasing oestrous mares by a stallion provokes the release of oxytocin. We therefore tested whether such elevated oxytocin levels reveal possible mate preferences as determined in typical preference tests.

Electrically assisted ocular gene therapy.

Electrotransfer and iontophoresis are being developed as innovative non-viral gene delivery systems for the treatment of eye diseases. These two techniques rely on the use of electric current to allow for higher transfection yield of various ocular cell types in vivo. Short pulses of relatively high-intensity electric fields are used for electrotransfer delivery, whereas the iontophoresis technique is based on the application of low voltage electric current. The basic principles of these techniques and their potential therapeutic application for diseases of the anterior and posterior segments of the eye are reviewed. Iontophoresis has been found most efficient for the delivery of small nucleic acid fragments such as antisense oligonucleotides, siRNA, or ribozymes. Electrotransfer, on the other hand, is being developed for the delivery of oligonucleotides or custom designed plasmids. The wide range of strategies already validated and the potential for targeting specific types of cells confirm the promising early observations made using electrotransfer and iontophoresis. These two nonviral delivery systems are safe and can be used efficiently for targeted gene delivery to ocular tissues in vivo. At the present, their application for the treatment of ocular human diseases is nearing its final stages of adaptation and practical implementation at the bedside.