Plastic physicians: The surgical salamanders of the COVID-19 pandemic.

At the time of writing, coronavirus disease-2019 (COVID-19) has affected 6.42 million people globally and over 380,000 deaths, with the United Kingdom now having the highest death rate in Europe. The plastic surgery department at Leeds Teaching Hospitals put necessary steps in place to maintain an excellent urgent elective and acute service whilst also managing COVID-positive medical patients in the ward. We describe the structures and pathways implemented together with complex decision-making, which has allowed us to respond early and effectively. We hope these lessons will prove a useful tool as we look to open conversations around the recovery of normal activity.

Cortisol metabolism, postnatal depression and weight changes in the first 12 months postpartum.

BACKGROUND & OBJECTIVES: Postnatal depression correlates with postpartum weight retention, and dysregulated cortisol metabolism is evident in depressed individuals. Cortisol metabolism, BMI and metabolic phenotype are robustly associated, but the role of cortisol metabolism in postnatal mental health and weight loss has never been examined. DESIGN: A longitudinal observation. PATIENTS: Forty nine healthy women with uncomplicated pregnancy. MEASUREMENTS: BMI and urinary steroid metabolites at 1 week and 1, 3, 6 and 12 months postpartum. Validated urinary steroid metabolite ratios were measured to determine the activities of 11ß-hydroxysteroid dehydrogenases (11ß-HSD) that interconvert inactive cortisone and active cortisol and the 5α-reductases that clear cortisol to its inactive metabolites. Postnatal depression symptoms were measured at 1, 6 and 12 months. RESULTS: Low 5α-reductase activity was associated with greater weight loss across the first year, independent of demographics, breastfeeding and depression. Postpartum BMI change was unrelated to postnatal depression at any time. Symptoms of postnatal depression were related to higher cortisol metabolite production at 12 months, independent of demographics and breastfeeding. CONCLUSIONS: Greatest weight loss in the postpartum year was associated with lower conversion of cortisone to cortisol and lower conversion of cortisol to its metabolites, supporting previous work that demonstrates the facilitative role of lower 5α-reductase and 11ß-HSD-1 in weight loss. Greater depression symptoms were associated with higher cortisol metabolite production rates. Whilst weight and mental health are both associated with dysregulation of the HPA axis, there may be different pathways towards depressed and obese phenotypes in healthy postpartum samples.

The corticosteroid metabolic profile of the mouse.

Data are presented on the urinary corticosteroid metabolic profile of the mouse strain 129/svJ. Through the use of GC/MS we have characterized, or tentatively identified corticosterone (Kendall's compound B) metabolites of both the 11beta-hydroxy and 11-carbonyl (compound A) series in urine. Full mass spectra of the methyloxime-trimethylether derivatives of 15 metabolites are included in the paper as an aid to other researchers in the field. Metabolites ranged in polarity from tetrahydrocorticosterone (THB) to dihydroxy-corticosterone with dominance of highly polar steroids. We found that prior to excretion corticosterone can undergo oxidation at position 11beta, reduction at position 20 and A-ring reduction. Metabolites retaining the 3-oxo-4-ene structure can be hydroxylated at position 6beta- as well as at an unidentified position, probably 16alpha-. Saturated steroids can be hydroxylated at positions 1beta-, 6alpha-, 15alpha- and 16alpha. A pair of hydroxy-20-dihydro-corticosterone metabolites (OH-DHB) were the most important excretory products accounting for about 40% of the total. One metabolite of this type was identified as 6beta-hydroxy-DHB; the other, of similar quantitative importance was probably 16alpha-hydroxy-DHB. The ratio of metabolites of corticosterone (B) to those of 11-dehydro-corticosterone (A) was greater than 9:1, considerably higher than that for the equivalent "human" ratio of 1:1 for cortisol to cortisone metabolites. Results from this study allowed the evaluation of 11beta-hydroxysteroid dehydrogenase (11beta-HSD) activity in mice with deleted glucose-6-phosphate transporter (G6PT). These mice had attenuated back-conversion of A to B resulting in an increased ratio of A-metabolites to B-metabolites [Walker EA, Ahmed A, Lavery GG, Tomlinson JW, Kim SY, Cooper MS, Stewart PM, 11beta-Hydroxysteroid dehydrogenase type 1 regulation by intracellular glucose-6-phosphate, provides evidence for a novel link between glucose metabolism and HPA axis function. J Biol Chem 2007;282:27030-6]. We believe this study is currently the most comprehensive on the urinary steroid metabolic profile of the mouse. Quantitatively less steroid is excreted in urine than in feces by this species but urine analysis is more straightforward and the hepatic metabolites are less subject to microbial degradation than if feces was analyzed.

Abnormal low-density lipoprotein subfraction profile in patients with untreated hypertension.

BACKGROUND: Low-density lipoprotein (LDL) consists of a heterogeneous group of particles of varying size and electrophoretic mobility. A predominance of small, more mobile particles is a risk factor for cardiovascular disease. AIM: To investigate the hypothesis that untreated patients with essential hypertension in the absence of vascular disease may exhibit abnormalities of LDL subfractions. SETTING: Specialist hypertension clinic. DESIGN: Cross-sectional study. METHODS: Following disc polyacrylamide gel electrophoresis, the mean (LDL locus) and heterogeneity (LDL spread) of mobility was recorded in 41 patients (mean age 52.6 years, 24 men) presenting with untreated essential hypertension (in the absence of vascular disease or diabetes mellitus) and in 45 healthy controls (age 56.9 years, 22 men) recruited from primary-care lists. RESULTS: Although there were no significant differences in total, low- or high-density lipoprotein cholesterol concentrations, LDL locus was significantly greater in the hypertensive group: mean (95%CI) 36.7 (35.7-37.6) vs. 34.8 (34.1-35.5), p=0.002. LDL locus was significantly elevated even in hypertensives with triglyceride concentrations below the median (<1.25 mmol/l). LDL spread was also greater in the hypertensive group, but not significantly: 5.6 (5.2-6.0) vs. 5.5 (5.3-5.8), p=0.10. DISCUSSION: Hypertensive patients have a preponderance of smaller LDL subfractions. This dyslipidaemia is not readily detected by conventional lipid assays.

Topical verapamil in glaucoma filtration surgery.

PURPOSE: Because of the reported antifibroblastic effect of verapamil, a calcium-channel blocker, we investigated the potential benefit of adjunctive topical verapamil in patients undergoing glaucoma filtration surgery. METHODS: This prospective, double-masked, randomized study included 56 eyes of 56 consecutive patients with chronic open-angle glaucoma undergoing trabeculectomy (primary or surgical revision of failed trabeculectomy), trabeculectomy combined with cataract surgery, or Molteno drainage device implantation. Postoperatively, the treated eyes received verapamil (0.25%) or one drop of placebo four times a day for 1 month in addition to 1% prednisolone four times a day and corticosteroid-antibiotic ophthalmic ointment at bedtime. RESULTS: There were no significant differences in preoperative mean intraocular pressure, mean number of medications, and glaucoma severity between the verapamil and placebo groups. There were also no significant differences between the two groups in filtration success rate, mean intraocular pressure, and mean number of medications on postoperative days 1, 4, or 7 and at postoperative months 1, 2, 3, 4, 5, and 6 (P > 0.05). CONCLUSION: There was no significant benefit of adjunctive topical verapamil when it was used after trabeculectomy, trabeculectomy combined with cataract surgery, or Molteno drainage device implantation.

Dyslipidaemia in patients with malignant-phase hypertension.

Low-density lipoprotein (LDL) consists of a heterogeneous group of particles of differing size, density and electrophoretic mobility, smaller particles being more atherogenic. A high proportion of small LDL particles is an independent risk factor for cardiovascular disease. We hypothesized that patients with malignant phase hypertension (MHT), the most severe form of hypertension, would demonstrate a more atherogenic LDL subfraction profile than either non-malignant hypertension (NMHT) or normotensive controls. We compared 16 patients with MHT to 41 patients with untreated NMHT and 45 normotensive controls. LDL subfraction profile was measured by disc polyacrylamide gel electrophoresis using a validated scoring system to calculate the mean size (locus) and heterogeneity (spread) of LDL subfraction mobilities. A higher LDL locus indicates a greater proportion of small LDL subfractions. LDL cholesterol levels were similar in all three groups (p=0.23). High-density lipoprotein cholesterol (HDL-C) levels were significantly lower (p<0.001) and serum triglyceride concentrations significantly higher (p=0.02) in the MHT group, compared to normotensive controls. LDL locus was greater in the NMHT group than in the normotensive controls and intermediate in the MHT group (p=0.008). There was no significant difference in LDL spread (p=0.26). Serum triglyceride concentrations were not significantly higher after adjusting for confounding variables. MHT is associated with an abnormal lipid profile, characterized by low HDL-cholesterol concentration. This dyslipidaemia may be partly responsible for the vascular complications and the poor prognosis of these patients.

Tumor cell invasion of model 3-dimensional matrices: demonstration of migratory pathways, collagen disruption, and intercellular cooperation.

We report a novel 3-dimensional model for visualizing tumor cell migration across a nylon mesh-supported gelatin matrix. To visualize migration across these model barriers, cell proteolytic activity of the pericellular matrix was detected using Bodipy-BSA (fluorescent upon proteolysis) and DQ collagen (fluorescent upon collagenase activity). For 3-dimensional image reconstruction, multiple optical images at sequential z axis positions were deconvoluted by computer analysis. Specificity was indicated using well-known inhibitors. Using these fluorescent proteolysis markers and imaging methods, we have directly demonstrated proteolytic and collagenolytic activity during tumor cell invasion. Moreover, it is possible to visualize migratory pathways followed by tumor cells during matrix invasion. Using cells of differing invasive potentials (uPAR-negative T-47D wild-type and uPAR-positive T-47D A2--1 cells), we show that the presence of the T-47D-A2--1 cells facilitates the entry of T-47D wild-type cells into the matrix. In some cases, wild-type cells follow T-47D A2--1 cells into the matrix whereas other T-47D-wild-type cells appear to enter without the direct intervention of T-47D A2--1 cells. Thus, we have developed a new 3-dimensional model of tumor cell invasion, demonstrated protein and collagen disruption, mapped the pathways followed by tumor cells during migration through an extracellular matrix, and illustrated cross-talk among tumor cell populations during invasion.

Expression and permeation properties of the K(+) channel Kir7.1 in the retinal pigment epithelium.

Bovine Kir7.1 clones were obtained from a retinal pigment epithelium (RPE)-subtracted cDNA library. Human RPE cDNA library screening resulted in clones encoding full-length human Kir7.1. Northern blot analysis indicated that bovine Kir7.1 is highly expressed in the RPE. Human Kir7.1 channels were expressed in Xenopus oocytes and studied using the two-electrode voltage-clamp technique. The macroscopic Kir7.1 conductance exhibited mild inward rectification and an inverse dependence on extracellular K+ concentration ([K+]o). The selectivity sequence based on permeability ratios was K+ (1.0) approximately Rb+ (0.89) > Cs+ (0.013) > Na+ (0.003) approximately Li+ (0.001) and the sequence based on conductance ratios was Rb+ (9.5) >> K+ (1.0) > Na+ (0.458) > Cs+ (0.331) > Li+ (0.139). Non-stationary noise analysis of Rb+ currents in cell-attached patches yielded a unitary conductance for Kir7.1 of approximately 2 pS. In whole-cell recordings from freshly isolated bovine RPE cells, the predominant current was a mild inwardly rectifying K+ current that exhibited an inverse dependence of conductance on [K+]o. The selectivity sequence based on permeability ratios was K+ (1.0) approximately Rb+ (0.89) > Cs+ (0.021) > Na+ (0.003) approximately Li+ (0.002) and the sequence based on conductance ratios was Rb+ (8.9) >> K+ (1.0) > Na+ (0.59) > Cs+ (0.23) > Li+ (0.08). In cell-attached recordings with Rb+ in the pipette, inwardly rectifying currents were observed in nine of 12 patches of RPE apical membrane but in only one of 13 basolateral membrane patches. Non-stationary noise analysis of Rb+ currents in cell-attached apical membrane patches yielded a unitary conductance for RPE Kir of approximately 2 pS. On the basis of this molecular and electrophysiological evidence, we conclude that Kir7.1 channel subunits comprise the K+ conductance of the RPE apical membrane.

Accreditation at the US EPA-NEIC. National Enforcement Investigations Center.

The US Environmental Protection Agency-National Enforcement Investigations Center (NEIC) of Denver, Colorado is the specialty technical arm of the Office of Enforcement and Compliance Assurance (OECA) within the US EPA. NEIC is a center for technical support nationwide to state, local, tribal, and federal environmental enforcement and compliance assurance programs. NEIC is a source of expertise for technical analysis, compliance monitoring, engineering evaluations, forensic laboratory activities, information management, computer forensics, and witness testimony. Effective 1 February 2001, NEIC was granted accreditation for overall environmental measurement activities that include field sampling, field measurements and monitoring, and laboratory measurements. NEIC became the first and only environmental forensic center in the United States to be granted this type of accreditation. The accreditation criteria incorporates nationally and internationally accepted forensic and quality management standards. Awarded by the National Forensic Science Technology Center (NFSTC), the NEIC Accreditation Standard was developed for conducting environmental measurements while adhering to forensic requirements in specific areas. The NEIC Accreditation Standard is based on ISO/IEC Guide 25 and ANSI/ASQC E4-1994, and it references specific aspects of the American Society of Crime Laboratory Directors/Laboratory Accreditation Board (ASCLD/LAB) Manual.

Molecular cloning and expression of an inwardly rectifying K(+) channel from bovine corneal endothelial cells.

PURPOSE: To determine the presence of a putative inwardly rectifying K(+) channel in bovine corneal endothelial (BCE) cells and to characterize its molecular and electrophysiological properties. METHODS: An RT-PCR strategy was used to clone an IRK1 channel sequence from BCE mRNA. Northern blot analysis was used to confirm expression of this sequence in cultured BCE cells. Two-electrode voltage-clamp and whole-cell patch-clamp recordings were used to characterize the cloned channel expressed in Xenopus oocytes and the native channels in cultured BCE cells, respectively. RESULTS: A full-length (1284 bp) coding sequence that shares 99.7% nucleotide sequence and 100% amino acid sequence identity to bovine lens IRK1 (Kir2.1) was cloned. The authors designate this sequence BCE IRK1 or BCIRK1. Northern blot analysis indicated that BCIRK1 mRNA is expressed in cultured BCE cells with two major transcripts of 7.5 and 5.5 kb. BCIRK1 cDNA was subcloned into the vector, pcDNA3.1(-), and cRNA transcribed from the BCIRK1 cDNA clone was injected into Xenopus oocytes. Two-electrode voltage-clamp recordings from injected oocytes revealed inwardly rectifying K(+) currents that were blocked by external Ba(2+) and Cs(+) in a concentration- and voltage-dependent manner. Whole-cell patch-clamp recordings from dissociated cultured BCE cells revealed strongly inwardly rectifying K(+) currents with similar properties. CONCLUSIONS: Corneal endothelial cells express IRK1 (Kir2.1) inwardly rectifying K(+) channels. Consistent with the properties of IRK1 channels, BCIRK1 is likely involved in regulating membrane potential and possibly other cellular functions in corneal endothelial cells.

Cloning and functional expression of human retinal kir2.4, a pH-sensitive inwardly rectifying K(+) channel.

To identify novel potassium channel genes expressed in the retina, we screened a human retina cDNA library with an EST sequence showing partial homology to inwardly rectifying potassium (Kir) channel genes. The isolated cDNA yielded a 2,961-base pair sequence with the predicted open reading frame showing strong homology to the rat Kir2. 4 (rKir2.4). Northern analysis of mRNA from human and bovine tissues showed preferential expression of Kir2.4 in the neural retina. In situ hybridization to sections of monkey retina detected Kir2.4 transcript in most retinal neurons. Somatic hybridization analysis and dual-color in situ hybridization to metaphase chromosomes mapped Kir2.4 to human chromosome 19 q13.1-q13.3. Expression of human Kir2. 4 cRNA in Xenopus oocytes generated strong, inwardly rectifying K(+) currents that were enhanced by extracellular alkalinization. We conclude that human Kir2.4 encodes an inwardly rectifying K(+) channel that is preferentially expressed in the neural retina and that is sensitive to physiological changes in extracellular pH.

Efficacy of apraclonidine 1% versus pilocarpine 4% for prophylaxis of intraocular pressure spike after argon laser trabeculoplasty.

OBJECTIVE: The authors compared the efficacy of apraclonidine 1% versus pilocarpine 4% prophylaxis of post-argon laser trabeculoplasty (ALT) intraocular pressure (IOP) spike. DESIGN: Prospective randomized clinical trial. PARTICIPANTS: Two hundred twenty-eight eyes of 228 patients with primary open-angle glaucoma undergoing ALT were studied. INTERVENTION: Patients were given 1 drop of either apraclonidine 1% (n = 114) or pilocarpine 4% (n = 114) 15 minutes before ALT. MAIN OUTCOME MEASURES: Peri-ALT IOPs and incidences of post-ALT IOP spikes at 5 minutes, 1 hour, and 24 hours were compared between the two groups. RESULTS: The two groups were similar in age, race, and medical dependency. Post-ALT mean IOPs at 5 minutes, 1 hour, and 24 hours were significantly lower than pre-ALT mean IOPs in both apraclonidine (P < 0.001) and pilocarpine (P < 0.001) groups. Incidences of IOP spikes greater than 1, 3, and 5 mmHg at 1 hour post-ALT were 21.1%, 14.9%, and 8.8% for the apraclonidine group and 12.3%, 5.3%, and 4.4% for the pilocarpine group (P = 0.076, 0.015, and 0.18 chi-square test). In the apraclonidine prophylaxis group, patients on long-term apraclonidine showed significantly higher incidence of post-ALT IOP spike than the patients without such long-term apraclonidine use (35.7%, 15 of 42 eyes, vs. 12.5%, 9 of 72 eyes; P = 0.003). In addition, peri-ALT pilocarpine prophylaxis tended to be less effective in patients undergoing long-term pilocarpine therapy but without statistical significance (17.4%, 8 of 46 eyes, vs. 9.4%, 6 of 64 eyes; P = 0.17). CONCLUSION: Peri-ALT pilocarpine 4% was at least as effective as, if not more effective than, apraclonidine 1% in post-ALT IOP spike prophylaxis. Peri-ALT apraclonidine prophylaxis was not effective in patients on long-term apraclonidine, and peri-ALT pilocarpine prophylaxis tended to be less effective in patients undergoing long-term pilocarpine therapy. Pilocarpine 4% can be considered as a first-choice drug for post-ALT IOP spike prophylaxis, especially in patients under treatment with apraclonidine.

The additive effect of latanoprost to maximum-tolerated medications with low-dose, high-dose, or no pilocarpine therapy.

OBJECTIVE: To assess the efficacy of latanoprost additive therapy in patients with intraocular pressure (IOP) out of control while taking maximum-tolerated medications and to determine whether pilocarpine therapy has a dose-dependent adverse effect on the efficacy of latanoprost therapy. DESIGN: Noncomparative case series. PARTICIPANTS: Sixty-one eyes of 61 patients with chronic glaucoma with IOP out of control while receiving maximum-tolerated medications were treated with latanoprost additive therapy on a compassionate basis. MAIN OUTCOME MEASURES: Follow-up was up to 22 months with a mean of 13.9 +/- 5.7 months. Kaplan-Meier survival analysis with Mantel-Cox log-rank test was performed to determine the overall success of latanoprost additive therapy and to compare the success rates of high-dose pilocarpine, low-dose pilocarpine, and no pilocarpine therapies. The criterion for success was avoiding glaucoma surgery with IOP decrease of 20% or greater and final IOP less than 22 mmHg. The IOP change and its significance for patients satisfying and failing the criterion for success also were determined to assess the latanoprost additive therapy. In addition, a number of pretreatment variables, including pilocarpine therapy, were analyzed for a significant effect on the efficacy of latanoprost additive therapy using Cox proportional hazards regression analysis. RESULTS: Latanoprost additive therapy significantly lowered mean IOP by 3.9 +/- 5.5 mmHg at 3 months and by 3.5 +/- 5.8 mmHg at 12 months. The cumulative success rate of the latanoprost additive therapy was 70% at 1 month, 42% at 3 months, 40% at 6 months, and 30% at 12 months. Of the variables studied, only increased number of previous incisional glaucoma surgeries and IOP greater than 24 mmHg before latanoprost additive therapy were significant prognostic factors for failure of latanoprost additive therapy. Pilocarpine therapy in any dose had no significant effect. CONCLUSION: This study supports a trial of latanoprost additive therapy before glaucoma surgery in patients with IOP out of control while receiving maximum-tolerated medications irrespective of pilocarpine therapy and the pilocarpine dosage, especially when the number of previous incisional glaucoma surgery is less than three and the IOP is less than 25 mmHg.

ATP-dependent regulation of inwardly rectifying K+ current in bovine retinal pigment epithelial cells.

Inwardly rectifying K+ current (IKir) in freshly isolated bovine retinal pigment epithelial (RPE) cells was studied in the whole cell recording configuration of the patch-clamp technique. When cells were dialyzed with pipette solution containing no ATP, IKir ran down completely in <10 min [half time (t1/2) = 1.9 min]. In contrast, dialysis with 2 mM ATP sustained IKir for 10 min or more. Rundown was also prevented with 4 mM GTP or ADP. When 0.5 mM ATP was used, IKir ran down by approximately 71%. Mg2+ was a critical cofactor because rundown occurred when the pipette solution contained 4 mM ATP but no Mg2+ (t1/2 = 1.8 min). IKir also ran down when the pipette solution contained 4 mM Mg2+ + 4 mM 5'-adenylylimidodiphosphate (t1/2 = 2.7 min) or 4 mM adenosine 5'-O-(3-thiotriphosphate) (t1/2 = 1.9 min), nonhydrolyzable and poorly hydrolyzable ATP analogs, respectively. We conclude that the sustained activity of IKir in bovine RPE requires intracellular MgATP and that the underlying mechanism may involve ATP hydrolysis.

Neuropeptide Y and the retinal pigment epithelium: receptor subtypes, signaling, and bioelectrical responses.

PURPOSE: To characterize the potential for neuropeptide Y (NPY) signaling in the retinal pigment epithelium (RPE) by identifying the NPY receptor subtypes present, determining the effect of NPY on second-messenger production and membrane conductance, and establishing the neural retina as a site of NPY gene expression. METHODS: Neuropeptide Y receptors present in bovine and human RPE were identified using ribonuclease protection assays and reverse transcriptase-coupled polymerase chain reaction. Assays of cyclic adenosine monophosphate (cAMP) and inositol phosphate production were performed using anion exchange chromatography and RPE cultures labeled with tritiated adenine or myo-inositol, respectively. Open-circuit recordings of transepithelial potential and resistance were performed using intact bovine RPE-choroid preparations. Neuropeptide Y-expressing cells in the retina were identified by staining for beta-galactosidase activity in eyes from mice in which lacZ replaces a portion of the NPY gene. RESULTS: Human RPE contained transcripts encoding Y1, Y2, and Y5 receptors, the predominant subtypes present in the central nervous system. Bovine RPE contained transcripts encoding Y2 receptors but not Y1 receptors. However, cultured cells contained transcripts encoding Y1 and Y2 receptors. Neuropeptide Y signaling in cultured bovine RPE occurred predominately through the Y2 receptor subtype, because nanomolar amounts of NPY and NPY13-36, but not [Leu31,Pro34]NPY, significantly inhibited isoproterenol-induced cAMP accumulation. Apical application of NPY increased the transepithelial potential in RPE-choroid preparations. This response was greatly diminished after basolateral membrane Cl- channels were blocked or changes in intracellular Ca2+ concentration were prevented with a Ca2+ chelator. The NPY gene was expressed in amacrine cells of the inner nuclear and ganglion cell layers of the mouse retina. CONCLUSIONS: The discovery of functionally coupled NPY receptors in the RPE represents the identification of a novel site of expression of this receptor family. The effects of NPY on the electrophysiologic properties of the bovine RPE are consistent with a potential paracrine role in regulating basolateral membrane Ca2+-sensitive Cl- conductance linked to Cl- and fluid transport.

Long-term outcome of primary glaucoma triple procedure with adjunctive 5-fluorouracil.

PURPOSE: To evaluate the long-term effect of adjunctive subconjunctival 5-fluorouracil (5-FU) on the filtration outcome of primary glaucoma triple procedure (PGTP) in primary open-angle glaucoma (POAG) patients. METHODS: Seventy-four POAG patients were randomly assigned to PGTP alone (36 patients) or PGTP with adjunctive subconjunctival 5-FU (5.0 +/- 1.3 injections of 5 mg each, total of 24.8 mg) (38 patients). After surgery, the patients were examined at regular intervals for intraocular pressure (IOP), visual acuity, medical therapy requirements, and complications. Surgical success was defined as IOP < or = 20 mmHg on postoperative medication < or = 1 without additional glaucoma surgery. RESULTS: Over an average follow-up (+/- SD) of 45.3 +/- 25.0 months, both 5-FU and control groups maintained significant improvement of IOP control and visual acuity. However, there were no statistically significant differences between the 5-FU and control groups with respect to postoperative IOP, number of glaucoma medications, visual acuity outcome, and success rate overall or in selected patients with one or more of the risk factors for filtration failure. CONCLUSIONS: The use of low-dose subconjunctival 5-FU (mean dosage of 24.8 mg in 5.0 +/- 1.3 injections) as an adjunct did not significantly improve the long-term filtration outcome of PGTP in POAG patients.

Assessment of swelling-activated Cl- channels using the halide-sensitive fluorescent indicator 6-methoxy-N-(3-sulfopropyl)quinolinium.

This study describes a quantitative analysis of the enhancement in anion permeability through swelling-activated Cl- channels, using the halide-sensitive fluorescent dye 6-methoxy-N-(3-sulfopropyl)quinolinium (SPQ). Cultured bovine corneal endothelial monolayers perfused with NO3- Ringer's were exposed to I- pulses under isosmotic and, subsequently, hyposmotic conditions. Changes in SPQ fluorescence due to I- influx were significantly faster under hyposmotic than under isosmotic conditions. Plasma membrane potential (Em) was -58 and -32 mV under isosmotic and hyposmotic conditions, respectively. An expression for the ratio of I- permeability under hyposmotic condition to that under isosmotic condition (termed enhancement ratio or ER) was derived by combining the Stern-Volmer equation (for modeling SPQ fluorescence quenching by I-) and the Goldman flux equation (for modeling the electrodiffusive unidirectional I- influx). The fluorescence values and slopes at the inflection points of the SPQ fluorescence profile during I- influx, together with Em under isosmotic and hyposmotic conditions, were used to calculate ER. Based on this approach, endothelial cells were shown to express swelling-activated Cl- channels with ER = 4.9 when the hyposmotic shock was 110 +/- 10 mosM. These results illustrate the application of the SPQ-based method for quantitative characterization of swelling-activated Cl- channels in monolayers.