Accelerated corneal crosslinking with 20'-soaking hydroxypropyl methyl cellulose/riboflavin vs conventional crosslinking with 30'-soaking dextran/riboflavin

PURPOSE

To evaluate and compare functional and structural outcomes of accelerated corneal crosslinking (A-CXL) using riboflavin with hydroxypropyl methyl cellulose (HPMC) vs conventional corneal crosslinking (C-CXL) using riboflavin with dextran.

SETTING

American University of Beirut Medical Center, Beirut, Lebanon.

DESIGN

Retrospective analysis.

METHODS

Retrospective analysis of 83 eyes of 73 patients with mild to moderate keratoconus. First group (n = 44 eyes) underwent C-CXL using a 30-minute riboflavin/dextran soaking between June 2014 and March 2016. Second group (n = 39 eyes) underwent A-CXL using a 20-minute riboflavin/HPMC soaking between April 2016 and December 2017. Patients were evaluated preoperatively and at 1, 3, and 12 months postoperatively. Main outcome measures were simulated keratometry (simK), maximum axial keratometry (Kmax), demarcation line depth, and haze intensity measured using optical coherence tomography-based image analysis software.

RESULTS

Demarcation line (DL) was 298.30 ± 64.60 μm and 335.61 ± 99.76 μm for C-CXL and A-CXL groups, respectively ( P = .04). Haze profile was similar for both groups. The mean simK values were reduced from 46.93 ± 3.50 and 46.44 ± 2.93 preoperatively to 46.18 ± 3.65 and 45.54 ± 2.78 at 12 months postoperatively, for C-CXL and A-CXL, respectively ( P = .003 for both groups). The mean Kmax decreased from 52.46 ± 4.82 and 51.50 ± 3.87 preoperatively to 51.30 ± 4.42 and 50.30 ± 3.52 postoperatively, for the C-CXL and A-CXL, respectively ( P < .001 for both groups). There was no difference in the simK and Kmax changes between the C-CXL and A-CXL groups ( P = .814 and P = .913), visual acuity, and refraction between the 2 groups ( P > .05).

CONCLUSIONS

A-CXL with a 20-minute riboflavin/HPMC soaking produced deeper DL and similar corneal haze, topographic, refractive, and visual results to C-CXL with a 30-minute riboflavin/dextran soaking.

The prolyl hydroxylase inhibitor GSK1120360A reduces early brain injury, but protection is not maintained in a neonatal rat model of hypoxic ischaemic encephalopathy

Hypoxic-ischemic encephalopathy (HIE) in newborns is associated with high morbidity and mortality, with many babies suffering long-term neurological deficits. Currently, treatment options are limited to therapeutic hypothermia, which is not appropriate for use in all babies. Previous studies have shown protective effects of increasing the transcription factor-hypoxia-inducible factor-1 (HIF-1) in animal models, by using mild hypoxia or compounds that act as prolyl hydroxylase inhibitors (PHIs). Here, we aimed to examine the neuroprotective actions of an orally active, small molecule PHI, GSK1120360A in a neonatal rat model of hypoxia-ischemia (HI) compared to another PHI, desferrioxamine (DFX). Sprague-Dawley rats underwent HI surgery on postnatal day 7 (P7), where unilateral carotid artery occlusion was performed followed by hypoxia (8% oxygen, 3 h). Initial testing showed that GSK1120360A and erythropoietin levels were detectable in plasma at 6 h following oral exposure to GSK1120360A. For the short-term neuroprotection study, pups were assigned to receive either saline (s.c), desferrioxamine (DFX-200 mg/kg, s.c), methylcellulose (1%, oral) or GSK1120360A (30 mg/kg, oral) immediately after HI. Histological analysis showed that GSK1120360A in this setting reduced brain injury size 7 days after HI, compared to the methylcellulose vehicle control group. DFX had no significant effect on injury size compared to saline group at the same 7 day timepoint. In the long-term neuroprotection study, pups were randomly assigned to be administered methylcellulose (1%, oral) or GSK1120360A (30 mg/kg, oral) immediately after HI. On P42, rats underwent behavioural testing using the forelimb grip strength, grid walking and novel object recognition tasks, and brains were collected for histological analysis. Long-term behavioural deficits were observed in grid walking, grip strength and novel object recognition tests after HI which were not improved in the GSK1120360A treatment group compared to the methylcellulose group. Similarly, there was no improvement in injury size on P42 in the GSK1120360A study group compared to the methylcellulose group. Here, we have shown that GSK1120360A can reduce brain injury at 7 days but that this neuroprotective benefit is not maintained when examined at 5 weeks after HI.

[MITOCHONDRIA-TARGETED ANTIOXIDANTS IN THE PREVENTION OF THE CORNEA EROSION WHEN PERFORMING SURGERY UNDER GENERAL ANESTHESIA.]

Despite the use of modern methods of prevention, at least 10% of patients operated on for ophthalmic indications not develop corneal erosion as the indirect complication of general anesthesia.

OBJECTIVE

To reduce the number of ophthalmic complications of general anesthesia by prophylactic use of new mito- chondria-targeted antioxidants - Vizomitin (eye drops).

MATERIALS AND METHODS

70 patients, which was supposed to perform the average duration of operations under general anesthesia were randomized into 3 groups depending on the method specific (pharmacological) prevention of corneal erosions: (1) control (specic (pharmacological) prevention was not carried out), (2), using preparation "natural tear, and (3) "Vizomitin" preparation. Postoperative biomicroscopy was performed to assess the condition of the cornea, tear film stability was measured and the height of the tear meniscus.

RESULTS

When using eye drops "Vizomitin" value is an indicator of stability of the tear film on the 3rd day after the operation more than in the control group of patients by 51% (p = 0.012) and patients groups, natural tear by 57% (p = 0.013). Surgical interventions performed under general anesthesia, leading to an increase in the number ofpatients with decreased tear meniscus height index of the control group with 4 to 7 patients (p = 0.30) in the group of natural tear from 3 to 11 patients (p = 0.008) . In the group with drug "Vizomitin" the number of such patients is reduced from 7 to 1 (p = 0.018).

CONCLUSION

In the surgical procedures under general anesthesia eye drops "Vizomitin" effectively prevents the devel- opment of corneal erosion.

Altered hepatic gene expression profiles associated with improved fatty liver, insulin resistance, and intestinal permeability after hydroxypropyl methylcellulose (HPMC) supplementation in diet-induced obese mice

The effect of hydroxypropyl methylcellulose (HPMC) on hepatic gene expression was analyzed by exon microarray and real-time PCR from livers of diet-induced obese (DIO) mice fed a high-fat (HF) diet supplemented with either 6% HPMC or 6% microcrystalline cellulose (MCC). HPMC-fed mice exhibited significantly reduced body weight gain (55% lower compared to MCC), liver weight (13%), plasma LDL-cholesterol concentration (45%), and HF diet-increased intestinal permeability (48%). HPMC significantly reduced areas under the curve for 2 h insulin and glucose responses, indicating enhanced insulin sensitivity and glucose metabolism. HPMC up-regulated hepatic genes related to fatty acid oxidation, cholesterol and bile acid synthesis, and cellular activation of glucocorticoid (bile acid recycling) and down-regulated genes related to oxidative stress, triglyceride synthesis, and polyunsaturated fatty acid elongation. In conclusion, HPMC consumption ameliorates the effects of a HF diet on intestinal permeability, insulin resistance, hepatic lipid accumulation, glucocorticoid-related bile acid recycling, oxidative stress, and weight gain in DIO mice.

Statins have therapeutic potential for the treatment of Alzheimer's disease, likely via protection of the neurovascular unit in the AD brain

Structural and functional abnormalities in the neurovascular unit (NVU) have been recently observed in Alzheimer's disease (AD). Statins, which are used clinically for reducing cholesterol levels, can also exert beneficial vascular actions, improve behavioral memory and reduce senile plaque (SP). Thus, we examined cognitive function, the serum level of lipids, senile plaque (SP), and the protective effects of statins on NVU disturbances in a mouse AD model. Amyloid precursor protein (APP) transgenic (Tg) mice were used as a model of AD. Atorvastatin (30 mg/kg/day, p.o.) or pitavastatin (3mg/kg/day, p.o.) were administered from 5 to 20 months of age. These 2 statins improved behavioral memory and reduced the numbers of SP at 15 and 20 M without affecting serum lipid levels. There was a reduction in immunopositive staining for N-acetyl glucosamine oligomer (NAGO) in the endothelium and in collagen IV in the APP vehicle (APP/Ve) group, with collagen IV staining most weakest near SP. There was also an increase in intensity and numbers of glial fibrillary acidic protein (GFAP) positive astrocytes, particularly around the SP, where MMP-9 was more strongly labeled. Double immunofluorescent analysis showed that astrocytic endfeet had detached from the capillary endothelium in the APP/Ve group. Overall, these data suggest that statins may have therapeutic potential for AD by protecting NVU.

Viscocannula-assisted reinversion of implantable collamer lens: comparison of postoperative outcomes with the fellow eyes

PURPOSE

To analyze and compare the postoperative outcomes of eyes with accidental intraoperative inversion of implantable collamer lens (ICL) and viscocannula-assisted reinversion in high myopia.

DESIGN

Retrospective observational case comparison.

METHODS

SETTING

Institutional practice.

PATIENTS

Consecutive eyes with accidental intraoperative inversion of ICL and viscocannula-assisted reinversion from January 2007 to September 2010 were analyzed retrospectively. They were compared with the fellow eyes with normal ICL implantation at 1 month, 6 months, and 2 years.

MAIN OUTCOME MEASURES

Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), corneal pachymetry, endothelial cell loss, intraocular pressure, lens transparency, anterior chamber depth, and postoperative uveitis.

RESULTS

A total of 206 myopic eyes had ICL implantation. Eight eyes (3.8%) of 8 patients had accidental intraoperative reinversion. Their fellow eyes had normal ICL implantation. There was no significant change (P = .611) in UCVA (reinverted and fellow eyes) at 2 years. There was no significant difference in postoperative UCVA (P = .611) and BCVA (P = .854) between the reinverted and the fellow eyes. The mean endothelial loss at 1 month, 6 months, and 2 years was 0.96% ± 0.5%, 0.92% ± 0.63%, and 0.89% ± 0.52% respectively in the reinverted eyes. There was no significant difference in the endothelial loss between the 2 groups at 1 month (P = .753), 6 months (P = .834), and 2 years (P = .916). One out of 8 eyes with reinversion had postoperative corneal edema, which resolved at 48 hours. None of the eyes reported uveitis or glaucoma. There was no loss of lens transparency.

CONCLUSION

Intraoperative inversion can occur during insertion of ICL and viscocannula-assisted reinversion can be performed without significant complications.

Management of irritable bowel syndrome in primary care: feasibility randomised controlled trial of mebeverine, methylcellulose, placebo and a patient self-management cognitive behavioural therapy website. (MIBS trial)

BACKGROUND

IBS affects 10-22% of the UK population. Abdominal pain, bloating and altered bowel habit affect quality of life, social functioning and time off work. Current GP treatment relies on a positive diagnosis, reassurance, lifestyle advice and drug therapies, but many suffer ongoing symptoms.A recent Cochrane review highlighted the lack of research evidence for IBS drugs. Neither GPs, nor patients have good evidence to inform prescribing decisions. However, IBS drugs are widely used: In 2005 the NHS costs were nearly £10 million for mebeverine and over £8 million for fibre-based bulking agents. CBT and self-management can be helpful, but poor availability in the NHS restricts their use. We have developed a web-based CBT self-management programme, Regul8, based on an existing evidence based self-management manual and in partnership with patients. This could increase access with minimal increased costs.

METHODS/DESIGN

The aim is to undertake a feasibility factorial RCT to assess the effectiveness of the commonly prescribed medications in UK general practice for IBS: mebeverine (anti-spasmodic) and methylcellulose (bulking-agent) and Regul8, the CBT based self-management website.135 patients aged 16 to 60 years with IBS symptoms fulfilling Rome III criteria, recruited via GP practices, will be randomised to 1 of 3 levels of the drug condition: mebeverine, methylcellulose or placebo for 6 weeks and to 1 of 3 levels of the website condition, Regul8 with a nurse telephone session and email support, Regul8 with minimal email support, or no website, thus creating 9 groups.

OUTCOMES

Irritable bowel symptom severity scale and IBS-QOL will be measured at baseline, 6 and 12 weeks as the primary outcomes. An intention to treat analysis will be undertaken by ANCOVA for a factorial trial.

DISCUSSION

This pilot will provide valuable information for a larger trial. Determining the effectiveness of commonly used drug treatments will help patients and doctors make informed treatment decisions regarding drug management of IBS symptoms, enabling better targeting of treatment. A web-based self-management CBT programme for IBS developed in partnership with patients has the potential to benefit large numbers of patients with low cost to the NHS. Assessment of the amount of email or therapist support required for the website will enable economic analysis to be undertaken.

Dose-response characteristics of high-viscosity hydroxypropylmethylcellulose in subjects at risk for the development of type 2 diabetes mellitus

BACKGROUND

Hydroxypropylmethylcellulose (HPMC) is a modified cellulose fiber that creates a viscous solution in the gastrointestinal tract. The present study examined the dose-response characteristics of high-viscosity (HV)-HPMC consumption on postprandial glucose and insulin levels in men and women at increased risk for type 2 diabetes mellitus.

METHODS

Subjects were a subset of participants in two trials with elevated peak postprandial glucose [>or=7.8 mmol/L (>or=140 mg/dL)] and body mass index (BMI) >or=27 kg/m(2). Subjects (n = 39) consumed breakfast meals containing 75 g of carbohydrate, each of which contained 1, 2, 4, or 8 g of HV-HPMC or a cellulose control in a randomized, double-blind manner. Each subject completed tests with control and two HV-HPMC doses.

RESULTS

Peak glucose concentration was lower than control (all P < 0.01) following 2 g (10%), 4 g (18%), and 8 g (20%) of HV-HPMC. Peak insulin was also reduced (P < 0.01) following 2 g (32%), 4 g (35%), and 8 g (46%) of HV-HPMC doses versus control. Incremental areas for glucose from 0 to 120 min were reduced by 8-40% versus control but only reached significance for the 4-g and 8-g conditions, whereas incremental areas under the insulin curves were reduced by 14-53% (P < 0.01 for 2, 4, and 8 g of HV-HPMC).

CONCLUSIONS

Among subjects at risk for type 2 diabetes mellitus, 1.0-8.0 g of HV-HPMC blunted postprandial glucose and insulin responses in a dose-dependent manner. Additional research is warranted to assess whether chronic consumption might retard the development or progression of glucose intolerance.

In vitro neural injury model for optimization of tissue-engineered constructs

Stem cell transplantation is a promising approach for the treatment of traumatic brain injury, although the therapeutic benefits are limited by a high degree of donor cell death. Tissue engineering is a strategy to improve donor cell survival by providing structural and adhesive support. However, optimization prior to clinical implementation requires expensive and time-consuming in vivo studies. Accordingly, we have developed a three-dimensional (3-D) in vitro model of the injured host-transplant interface that can be used as a test bed for high-throughput evaluation of tissue-engineered strategies. The neuronal-astrocytic cocultures in 3-D were subjected to mechanical loading (inducing cell death and specific astrogliotic alterations) or to treatment with transforming growth factor-beta1 (TGF-beta1), inducing astrogliosis without affecting viability. Neural stem cells (NSCs) were then delivered to the cocultures. A sharp increase in the number of TUNEL(+) donor cells was observed in the injured cocultures compared to that in the TGF-beta1-treated and control cocultures, suggesting that factors related to mechanical injury, but not strictly astrogliosis, were detrimental to donor cell survival. We then utilized the mechanically injured cocultures to evaluate a methylcellulose-laminin (MC-LN) scaffold designed to reduce apoptosis. When NSCs were co-delivered with MC alone or MC-LN to the injured cocultures, the number of caspase(+) donor cells significantly decreased compared to that with vehicle delivery (medium). Collectively, these results demonstrate the utility of an in vitro model as a pre-animal test bed and support further investigation of a tissue-engineering approach for chaperoned NSC delivery targeted to improve donor cell survival in neural transplantation.

Efficacy, tolerability and comfort of a 0.3% hypromellose gel ophthalmic lubricant in the treatment of patients with moderate to severe dry eye syndrome

OBJECTIVE

To evaluate efficacy, safety and comfort of a 0.3% hypromellose (HM) eye gel (GenTeal Lubricant Eye Gel), with a sodium perborate preservative system and carbomer gelling agent, in patients with dry eye.

RESEARCH DESIGN AND METHODS

Patients with moderate-to-severe dry eye syndrome were enrolled in this open label study and assessed at three visits; a screening consultation (baseline) and two follow-up visits on day 14 (+/- 4 days) and day 28 (+/- 4 days). All screening, evaluation and follow-up visits were carried out at the Tauber Eye Center (formerly the Hunkeler Eye Center), Kansas City. Patients were treated with the product over a 4-week period. They were instructed to use the product at least two times daily, more if necessary, with one drop instilled into the conjunctive sac of both eyes.

MAIN OUTCOME MEASURES

Efficacy was measured by ocular symptoms (burning, stinging, foreign body sensation, dryness, pain/soreness and photophobia), ocular signs (eyelid erythema, bulbar conjunctival injection and corneal superficial punctate keratitis score), tear breakup time and global assessment of ocular comfort. Tolerability measures were change from baseline in best corrected Snellen visual acuity and monitoring of adverse events.

RESULTS

Thirty-seven patients completed this study. The mean sum symptom score at each visit was significantly lower compared with baseline with approximately 30% reduction in the sum symptom score at 2 weeks and approximately 33% at 4 weeks after treatment initiation (p < 0.001). Mean individual symptom scores for dryness, stinging and foreign body sensation decreased by approximately 40% at the end of the study (p < 0.02). Tear breakup time increased from baseline by 53% and 59% at 2 and 4 weeks, respectively (p < 0.001). The proportion of patients reporting a global evaluation of slightly better or much better was approximately 74% at 2 weeks and 78% at 4 weeks after treatment initiation. The product was well tolerated, with one related adverse event reported.

CONCLUSIONS

In a small, open-label study, this 0.3% HM eye gel showed statistically significant effects in relieving ocular symptoms and provides a well-tolerated formula that effectively reduced symptoms and improved ocular comfort in patients with dry eye syndrome.

Hydroxypropylmethylcellulose significantly lowers blood cholesterol in mildly hypercholesterolemic human subjects

OBJECTIVE

To determine the cholesterol-lowering efficacy of hydroxypropylmethylcellulose (HPMC) in mildly hypercholesterolemic humans.

SUBJECTS

Trial one: entry mean (range) total serum cholesterol values of eight female and four male subjects were 6.48 (5.57-7.51) mmol l(-1) (250 (215-290) mg dl(-1)) and 6.60 (5.57-7.64) mmol l(-1) (255 (215-295) mg dl(-1)), respectively. Trial two: corresponding values for 20 women and 20 men were 5.96 (5.43-6.48) mmol l(-1) 230 (210-250) mg dl(-1)) and 6.05 (5.46-6.63) mmol l(-1) 233 (211-256) mg dl(-1)), respectively.

RESULTS

Trial one: HPMC decreased (P< or =0.05) total and LDL-cholesterol 9.3 and 15.3% (medium), 16.9 and 23.5% (high) and 13.8 and 19.4% (ultra-high), respectively, over placebo. Trial two: total and LDL-cholesterol decreased (P< or =0.05) throughout the 8 weeks, with mean (weeks 4-8) reductions of 7 and 8% at 5 g day(-1), and 12 and 15% at 15 g day(-1), respectively, over placebo. Adverse effects were minimal. Trial one: medium, high and ultra-high viscosity HPMC at 15 g day(-1) for 1 week each;1-week wash-out between treatments. Trial two: ultra-high viscosity HPMC at 5 or 15 g day(-1) for 8 weeks.

CONCLUSIONS

HPMC soluble fiber, especially high-viscosity grades, significantly lowers cholesterol at well-tolerated doses, showing promise as a treatment of hypercholesterolemia.

The influence of viscoelastic substances on the corneal endothelial cell population during cataract surgery: a prospective study of cohesive and dispersive viscoelastics

PURPOSE

To compare the ability of cohesive and dispersive ophthalmic viscoelastic devices (OVDs) to protect the corneal endothelium following in-the-bag phacoemulsification with implantation of a foldable posterior chamber intraocular lens (IOL).

METHODS

In a prospective single-masked randomized study, 60 eyes of 60 cataract patients were assigned to three groups of 20 patients each, according to which OVD was used: Celoftal, Vitrax or Healon. The corneal response to surgery was evaluated by measuring the endothelial cell loss, the variation in mean cell area of the endothelial cells (CV), the frequency of hexagonal cells, and the central corneal thickness. Data were recorded preoperatively and 3 months postoperatively.

RESULTS

Preoperatively, no significant difference was observed in cell count, CV, hexagonal pattern or pachymetry among groups. Postoperatively, all three groups had a significant decrease in cell count, but the decrease was significantly less in the Vitrax group (6.97%) than in the Celoftal (18.03%) and Healon groups (18.46%). No changes in CV, hexagonality or corneal thickness were observed within any of the three groups or among the groups. There was an equal and significant increase in visual acuity.

CONCLUSIONS

Phacoemulsification with implantation of a posterior chamber lens is known to affect the density and morphology of corneal endothelial cells. Viscoelastics facilitate cataract surgery and protect the corneal endothelium during the procedure. Choosing a dispersive hyaluronate OVD during the phaco procedure may allow for protection of the endothelial cells while suppressing the formation of free radicals. This may be the reason for the superior protective effect on the corneal endothelial cells of Vitrax compared with Celoftal and Healon.

Effect of an oil-in-water emulsion on the tear physiology of patients with mild to moderate dry eye

PURPOSE

To determine the effect of an oil-in-water emulsion eye drop compared with a conventional dry eye supplement (hypromellose) on tear physiology in dry eye.

METHODS

A randomized parallel, longitudinal, and investigator-masked study of the efficacy of 1.25% castor oil emulsion and 0.32% hypromellose solution was carried out. A total of 53 patients with mild to moderate dry eye (27 in emulsion group and 26 in hypromellose group) were recruited for the study. Patients were enrolled if they reported at least 2 symptoms on a McMonnies Dry Eye Questionnaire together with 1 of the following screening tests: noninvasive tear breakup time (5-10 seconds) and Schirmer test without anesthesia (2-5 mm in 5 minutes). Patients were instructed to use the test solutions 3 times a day for 30 days. Tear production, evaporation, lipid layer structure, and osmolality were measured before and 30 days after use of the drops.

RESULTS

A statistically significant decrease was seen after 1 month in tear evaporation rates with both emulsion (7.25 +/- 5.43 g/m2/h) and hypromellose (2.02 +/- 4.75 g/m2/h). However, the decrease with emulsion was significantly greater than with hypromellose (P < 0.001). Lipid layer structure improved from day 1 to day 30 of the study with the emulsion but not with the hypermellose. No significant changes were seen in tear production and osmolality with either of the drops.

CONCLUSIONS

The oil-water emulsion was more effective in reducing tear evaporation than hypromellose after repeated application over a 1-month period. This finding signifies the potential of the emulsion in the management of evaporative dry eye.

Performance profile of sodium hyaluronate in patients with lipid tear deficiency: randomised, double-blind, controlled, exploratory study

AIM

To assess the short-term efficacy of hypotonic 0.18% sodium hyaluronate in patients with evaporative tear-sufficient dry eye due to lipid tear deficiency (LTD).

METHODS

This was a randomised, double-blind, controlled, exploratory study. A total of 10 patients with dry eye due to LTD were treated as follows: one drop of hypotonic 0.18% sodium hyaluronate in one eye and one drop of isotonic 0.3% hydroxypropyl-methylcellulose (HPMC)/0.1% dextran in the other eye. Non-invasive tear film break-up time (NIBUT) evaluated by using a tear scope with grid pattern and subjective ocular symptoms of dry eye were assessed at 15, 30, 60 and 90 min after instillation.

RESULTS

Both sodium hyaluronate and HPMC/dextran caused a significant (p<0.05) improvement in NIBUT and symptoms. Mean (SD) NIBUT in the sodium hyaluronate group was 3.2 (1.0), 6.4 (2.8), 5.5 (1.9), 5.3 (1.3) and 3.9 (1.7) s at 0, 15, 30, 60 and 90 min, respectively, compared with 3.6 (1.9), 5.5 (3.2), 5.0 (1.5), 4.4 (2.2) and 3.5 (1.2) s in the HPMC/dextran group. However, increase in NIBUT was significantly (p<0.05) greater and longer in the sodium hyaluronate group than in the HPMC/dextran group.

CONCLUSION

Treatment with sodium hyaluronate and HPMC/dextran eye drops is useful for treating patients with dry eye due to LTD. However, sodium hyaluronate caused a significantly (p<0.05) greater increase in NIBUT values than HPMC/dextran in such patients.

Study of an alginate/HPMC-based in situ gelling ophthalmic delivery system for gatifloxacin

The poor bioavailability and therapeutic response exhibited by conventional ophthalmic solutions due to rapid pre-corneal elimination of the drug may be overcome by the use of in situ gel-forming systems that are instilled as drops into the eye and then undergo a sol-gel transition in the cul-de-sac. The present work describes the formulation and evaluation of an ophthalmic delivery system of an antibacterial agent, gatifloxacin, based on the concept of ion-activated in situ gelation. Alginate (Kelton) was used as the gelling agent in combination with HPMC (Methocel E50Lv) which acted as a viscosity-enhancing agent. The rheological behaviors of all formulations were not affected by the incorporation of gatifloxacin. Both in vitro release studies and in vivo pre-corneal retention studies indicated that the alginate/HPMC solution retained the drug better than the alginate or HPMC E50Lv solutions alone. These results demonstrate that the alginate/HPMC mixture can be used as an in situ gelling vehicle to enhance ocular bioavailability and patient compliance.

Change in intraocular pressure within 1 week of phacoemulsification and intraocular lens implantation using Adatocel

PURPOSE

To examine the change in intraocular pressure (IOP) within 1 week of phacoemulsification and foldable posterior chamber intraocular lens (PC IOL) implantation using Adatocel (hydroxypropyl methylcellulose 2% [HPMC]).

SETTING

Department of Ophthalmology, University of Sciences, Faculty of Medicine, Pécs, Hungary.

METHODS

In this prospective study, the IOP in 118 eyes of 118 patients (57 men, 61 women, mean age 68 years +/- 7.8 [SD]) with no history of glaucoma was assessed by Goldmann applanation tonometry 2 to 3, 6 to 8, and 22 to 24 hours and 1 week after uneventful phacoemulsification and PC IOL implantation. The effect of the removal of Adatocel ("partial removal" from the anterior chamber [AC] only versus "complete removal" from behind of the IOL as well), the lens type (Medicontur 601 HP versus Bausch & Lomb Hydroview), and the type of anesthesia (topical versus parabulbar) were compared. Statistical analysis was performed using the Student t test, and P< or =.05 was considered statistically significant.

RESULTS

The mean preoperative IOP was 13.83 +/- 2.5 mmHg. There were no significant differences at any time in postoperative IOP measurements between the 2 IOL types and the 2 modes of anesthesia. At 2 to 3 hours, 6 to 8 hours, and 22 to 24 hours, the IOP was significantly higher in the 30 eyes in which the Adatocel was partially removed (from the AC only) than in the 88 eyes in which it was completely removed (from behind the PC IOL as well) (P< or =.05, P< or =.01, and P< or =.001, respectively).

CONCLUSION

Severe postoperative IOP spikes in nonglaucomatous patients after uneventful phacoemulsification cataract surgery are rare. The type of implanted PC IOL and the mode of anesthesia had no significant effect on postoperative IOP. Total removal of the ophthalmic viscosurgical device, even when using HPMCs such as Adatocel, is necessary to prevent postoperative IOP spikes.

Methyl cellulose gel obstructed bone formation by GBR: an experimental study in rats

AIM

To evaluate whether bone formation under Teflon capsules may be enhanced by concomitant implantation of recombinant human platelet-derived growth factor-BB/insulin-like growth factor-I (rhPDGF-BB/IGF-I) incorporated into a methyl cellulose gel.

MATERIALS AND METHODS

Fifty-five male 6-month-old albino rats of the Wistar strain were used in the study. The lateral aspect of the mandibular ramus was exposed on both sides of the jaw. In 70 sites, the periosteum was removed from the ramus, leaving the bone denuded, while in 35 sites, it was preserved. On 10 non-periosteal (P-) sites and five periosteal (P+) sites, an empty rigid teflon capsule (d=7 mm), serving as control, was placed on the ramus. In the 40 test animals, the capsule placed on the one side of the jaw was filled at random with one of three different concentrations (1,200, 600, 150 microg/ml) of rhPDGF-BB/IGF-I gel. The capsules placed on the contralateral side of the jaw contained a placebo methyl cellulose gel. Each growth factor group, defined according to the gel concentration, and the placebo group contained 10 capsules placed on the P- side and five capsules placed on the P+ side. Two months after surgery, all animals were sacrificed.

RESULTS

Histologic analysis revealed that in the non-filled control capsules, the amount of new bone including the bone marrow was 29.9% and 39.7% of the capsule area on the P- and P+ sides, respectively. In the test capsules with the growth factor gel and placed on the P-sides, the amounts of new bone ranged from 5.6% to 6.3%, which were similar (p>0.05) to that formed in the capsules filled with the methyl cellulose gel (5.5%). New bone formation was larger in the capsules on the P+ sides than in those on the P- sides but was similar in the capsules with different growth factor concentrations (range 17.9-19.6%) and in those with placebo gel (21.0%). In all groups, the carrier gel was poorly absorbed and occupied most of the capsules.

CONCLUSION

Local application of a methyl cellulose gel obstructed bone formation under Teflon capsules placed adjacent to uninjured cortical bone in the mandibular ramus of rats. These data suggest that another material should be utilized to deliver growth factors under Teflon membranes for guided bone regeneration.

Artificial Tear Gel as a Gonioscopic and Contact Lens Ophthalmoscopy Fluid

An easy and convenient method of using a commercially available clear lubricant eye gel for diagnostic and therapeutic contact lens applications at the slit lamp is described. The authors used hydroxypropyl methylcellulose 0.3% as a medium for contact lens applications and compared it to the traditional hydroxypropyl methylcellulose 2.5%. Hydroxypropyl methylcellulose 0.3% as a contact lens solution is clear, viscous, and easy to apply; does not require irrigation after use; and has levels of convenience, safety, and visual recovery superior to the standard 2.5% solution characteristics. The 0.3% gel could be used as an effective and convenient gonioscopic and ophthalmoscopic contact medium.

Matrix inclusion within synthetic hydrogel guidance channels improves specific supraspinal and local axonal regeneration after complete spinal cord transection

We have previously shown that a novel synthetic hydrogel channel composed of poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (pHEMA-MMA) is biocompatible and supports axonal regeneration after spinal cord injury. Our goal was to improve the number and type of regenerated axons within the spinal cord through the addition of different matrices and growth factors incorporated within the lumen of the channel. After complete spinal cord transection at T8, pHEMA-MMA channels, having an elastic modulus of 263+/-13 kPa were implanted into adult Sprague Dawley rats. The channels were then filled with one of the following matrices: collagen, fibrin, Matrigel, methylcellulose, or smaller pHEMA-MMA tubes placed within a larger pHEMA-MMA channel (called tubes within channels, TWC). We also supplemented selected matrices (collagen and fibrin) with neurotrophic factors, fibroblast growth factor-1 (FGF-1) and neurotrophin-3 (NT-3). After channel implantation, fibrin glue was applied to the cord-channel interface, and a duraplasty was performed with an expanded polytetrafluoroethylene (ePTFE) membrane. Controls included animals that had either complete spinal cord transection and implantation of unfilled pHEMA-MMA channels or complete spinal cord transection. Regeneration was assessed by retrograde axonal tracing with Fluoro-Gold, and immunohistochemistry with NF-200 (for total axon counts) and calcitonin gene related peptide (CGRP, for sensory axon counts) after 8 weeks survival. Fibrin, Matrigel, methylcellulose, collagen with FGF-1, collagen with NT-3, fibrin with FGF-1, and fibrin with NT-3 increased the total axon density within the channel (ANOVA, p<0.05) compared to unfilled channel controls. Only fibrin with FGF-1 decreased the sensory axon density compared to unfilled channel controls (ANOVA, p<0.05). Fibrin promoted the greatest axonal regeneration from reticular neurons, and methylcellulose promoted the greatest regeneration from vestibular and red nucleus neurons. With Matrigel, there was no axonal regeneration from brainstem motor neurons. The addition of FGF-1 increased the axonal regeneration of vestibular neurons, and the addition of NT-3 decreased the total number of axons regenerating from brainstem neurons. The fibrin and TWC showed a consistent improvement in locomotor function at both 7 and 8 weeks. Thus, the present study shows that the presence and type of matrix contained within synthetic hydrogel guidance channels affects the quantity and origin of axons that regenerate after complete spinal cord transection, and can improve functional recovery. Determining the optimum matrices and growth factors for insertion into these guidance channels will improve regeneration of the injured spinal cord.

Experimental ischemic wounds: correlation of cell proliferation and insulin-like growth factor I expression and its modification by different local IGF-I release systems

We investigated cell proliferation and local insulin-like growth factor-I (IGF-I) expression in ischemic wounds after topical application of IGF-I through different delivery systems. IGF-I dressings were fabricated from an IGF-I containing polyvinyl alcohol film placed on a standard hydrogel dressing. In vitro, the release of IGF-I from this dressing was assessed by enzyme-linked immunosorbent assay. For animal experiments, a standardized ischemic skin flap containing a full-thickness wound was created on the back of male Sprague-Dawley rats. An identical wound outside the flap served as control. We initially investigated intracutaneous pO2 (p(ti)O2), cell proliferation, and local IGF-I expression. In a second setting, wounds were treated either with IGF-I dissolved in methylcellulose gel or with an IGF-I dressing, and ulcer size and cell proliferation were assessed. In vitro, approximately 60% of IGF-I was released from the IGF-I dressing, compared to a 97% release from methylcellulose gel. In vivo, ischemic wounds showed less cell proliferation and decreased IGF-I expression than nonischemic wounds. A lower local p(ti)O2 correlated with larger wound size, less cell proliferation, and decreased IGF-I expression. Ulcer size was reduced after treatment with either IGF-I dressing or methylcellulose gel. However, cell proliferation only increased after treatment with IGF-I dressing, but not after methylcellulose gel treatment. We conclude that IGF-I expression is decreased in ischemic wounds and correlates with low cell proliferation. This can be reversed by local IGF-I application, but the efficacy of treatment depends on the delivery system.

Hydroxypropyl methylcellulose (HPMC) lubricant facilitates insertion of porous spherical orbital implants

The insertion of an orbital implant in the posterior Tenon's space or in the eviscerated sclera must be smooth, without entrapment or dragging of adjacent soft tissue. Anterior Tenon's fascia and conjunctiva must be closed without undue tension that could lead to subsequent postoperative implant exposure. Current methods to prevent tissue drag include passing the implant via a cut "thumb" from a surgeon's glove, the use of a prepackaged rigid plastic funnel, or a specialized orbital implant introducing forceps, e.g., Carter sphere injector. We recommend also coating the porous implant with an inert semisynthetic viscoelastic polymer, thus enabling easy placement. We illustrate this in a typical case.

Alveolar bone regeneration for immediate implant placement using an injectable bone substitute: an experimental study in dogs

BACKGROUND

The aim of the present study was to assess the efficacy of a ready-to-use injectable bone substitute for bone regeneration around dental implants placed into fresh extraction sockets.

METHODS

Third and fourth mandibular premolars were extracted from three beagle dogs and the interradicular septa were surgically reduced to induce a mesial bone defect. Thereafter, titanium implants were immediately placed. On the left side of the jaw, mesial bone defects were filled with an injectable bone substitute (IBS), obtained by combining a polymer and biphasic calcium phosphate ceramic granules. The right defects were left unfilled as controls. After 3 months of healing, specimens were prepared for histological and histomorphometric evaluations.

RESULTS

No post-surgical complications were observed during the healing period. In all experimental conditions, histological observations revealed a lamellar bone formation in contact with the implant. Histomorphometric analysis showed that IBS triggers a significant (P<0.05) increase in terms of the number of threads in contact with bone, bone-to-implant contact, and peri-implant bone density of approximately 8.6%, 11.0%, and 14.7%, respectively. In addition, no significant difference was observed when number of threads, bone-to-implant contact, and bone density in the filled defects were compared to the no-defect sites.

CONCLUSION

It is concluded that an injectable bone substitute composed of a polymeric carrier and calcium phosphate significantly increases bone regeneration around immediately placed implants.

[Left ventricular free wall rupture]

BACKGROUND

Left ventricular (LV) free wall rupture is an uncommon but catastrophic event after acute myocardial infarction and is associated with a high mortality. Some patients may be salvaged with emergent operation. Padro et al. described a sutureless technique for the treatment of postinfarction LV free wall rupture. We have adopted a similar sutureless technique using a fibrin glue-oxycellulose fixation.

METHODS

A review of 32 patients during a 20-year period who were referred to coronary care unit (CCU) with postinfarction LV free wall rupture was conducted. There were 17 men and 15 women with an average age of 68.8 years. Nine patients were treated who having one-stage operation of simultaneous 7 ventricular septal perforation and 2 coronary artery bypass grafting (CABG). Nine patients were sutured directly with a felt sandwich technique with or without cardiopulmonary bypass. Five patients were treated with pericardiectomy and pericardiocentesis using direct vision. Nine patients were sealed with sutureless method using fibrin glue-oxycellurose fixation without cardiopulmonary bypass.

RESULTS

Eleven hospital deaths (34.4%, 11/32) were occurred in the all patints. However, 1 death (7.1%, 1/14) occurred in the pericardiectomy and in the sutureless sealed groups.

CONCLUSIONS

A sutureless technique for an oozing type of postinfarction LV free wall rupture is effective.

Oxidative tissue damage after phacoemulsification: influence of ophthalmic viscosurgical devices

PURPOSE

To quantify the oxidative tissue damage after phacoemulsification, correlate the damage to the energy applied, and investigate the influence of ophthalmic viscosurgical devices (OVDs).

SETTING

Department of Ophthalmology, University of Mainz, Mainz, Germany.

METHODS

The study comprised 130 eyes operated on by 1 surgeon using the same phacoemulsification machine. Some eyes received an OVD before phacoemulsification and some did not. Energy values were expressed as phaco time; that is, ultrasound (US) time (seconds) after conversion to 100% phaco power. Patients were grouped as follows: Group 1, phaco time less than 20 seconds and no OVD; Group 2, phaco time 20 to 40 seconds and no OVD; Group 3, phaco time more than 40 seconds and no OVD; Group 4, phaco time 20 to 40 seconds and hydroxypropyl methylcellulose 2% (HPMC); Group 5, phaco time 20 to 40 seconds and sodium hyaluronate 1%. Aqueous humor from pseudophakic eyes served as a control. At the end of surgery, anterior chamber fluid was analyzed for lipid peroxides using the thiobarbituric acid method.

RESULTS

Lipid peroxides were detected in all groups. The values were significantly higher in Group 2 than in Group 1 (P<.01) and in Group 3 than in Groups 1 and 2 (P<.01). The differences in lipid peroxide values between all phaco groups and the control group were statistically significant. Sodium hyaluronate 1% and HPMC 2% produced significantly lower lipid peroxide values than in the respective phaco groups that did not receive an OVD (both P<.01).

CONCLUSIONS

Oxidative tissue damage occurred during phacoemulsification. The damage, which correlated with the US energy applied, can be reduced by the use of OVDs.

A randomised controlled study of the efficacy of hypromellose and Lacri-Lube combination versus polyethylene/Cling wrap to prevent corneal epithelial breakdown in the semiconscious intensive care patient

OBJECTIVE

To compare the efficacy of two forms of eye care (hypromellose and Lacri-Lube combination vs polyethylene/Cling wrap covers) for intensive care patients.

DESIGN

Randomised-controlled trial.

SETTING

University affiliated, tertiary referral hospital.

PATIENTS AND PARTICIPANTS

One hundred ten patients with a reduced or absent blink reflex were followed through until they regained consciousness, were discharged from the facility during study enrolment, died or developed a positive corneal ulcer or eye infection.

INTERVENTIONS

All patients received standard eye cleansing every 2 h. In addition to this, group one ( n=60) received a treatment combining hypromellose drops and Lacri-Lube (HL) to each eye every 2 h. Group two ( n=50) had polyethylene covers only placed over the eye to create a moisture chamber.

MEASUREMENTS AND RESULTS

Corneal ulceration was determined using corneal fluorescein stains and mobile slit lamp evaluation, performed daily. No patients had corneal ulceration in the polyethylene cover group, but 4 patients had corneal ulceration in the HL group.

CONCLUSIONS

Polyethylene covers are as effective as HL in reducing the incidence of corneal damage in intensive care patients.

Double-layered mucoadhesive tablets containing nystatin

The objective of this work was to design a mucoadhesive tablet with a potential use in the treatment of oral candidosis. A 2-layered tablet containing nystatin was formulated. Lactose CD (direct compression), carbomer (CB), and hydroxypropylmethylcellulose (HPMC) were used as excipients. Tablets were obtained through direct compression. Properties such as in vitro mucoadhesion, water uptake, front movements, and drug release were evaluated. The immediate release layer was made of lactose CD (100 mg) and nystatin (30 mg). The CB:HPMC 9:1 mixture showed the best mucoadhesion properties and was selected as excipient for the mucoadhesive polymeric layer (200 mg). The incorporation of nystatin (33.3 mg) in this layer affected the water uptake, which, in turn, modified the erosion front behavior. Nystatin showed a first-order release. The polymeric layer presented an anomalous kinetic (n = 0.82) when this layer was individually evaluated. The mucoadhesive tablet formulated in this work releases nystatin quickly from the lactose layer and then in a sustained way, during approximately 6 hours, from the polymeric layer. The mixture CB:HPMC 9:1 showed good in vitro mucoadhesion. A swelling-diffusion process modulates the release of nystatin from this layer. A non-Fickian (anomalous) kinetic was observed.

Corneal endothelial cell protection with a dispersive viscoelastic material and an irrigating solution during phacoemulsification: low-cost versus expensive combination

PURPOSE

To evaluate the protective effect on corneal endothelial cells of a low-cost and an expensive combination of a dispersive viscoelastic material and an irrigating solution during phacoemulsification.

SETTING

Department of Ophthalmology, University of Vienna, Vienna, Austria.

METHODS

This prospective randomized examiner- and patient-masked study comprised 90 eyes of 45 consecutive patients with age-related cataract in both eyes. For each patient, the first eye was randomly assigned to receive hydroxypropyl methylcellulose 2% (Ocucoat) and Ringer's solution (low-cost combination) or sodium chondroitin sulfate 4%-sodium hyaluronate 3% (Viscoat) and an enriched balanced salt solution (BSS Plus) (expensive combination) during phacoemulsification. The contralateral eye received the other treatment. Endothelial cell function was evaluated by measuring corneal thickness (CT) using partial coherence interferometry, morphology assessment, and endothelial cell counts.

RESULTS

The acute postoperative increase in CT was +9.8 microm in the low-cost group and +10.9 microm in the expensive group; the difference between groups was not significant. After 1 month, the CT still differed significantly from baseline in the low-cost group. Three months after surgery, the CT had returned to baseline values in both groups. There was no significant between-group difference in endothelial cell counts or morphology.

CONCLUSIONS

During phacoemulsification in a nonselected patient population, there was no difference in acute postoperative corneal edema and endothelial cell morphology after 3 months between a Viscoat and BSS Plus combination and an Ocucoat and Ringer's solution combination. Eyes receiving the expensive combination had marginally faster recovery of corneal swelling by 3 months. However, the cost of Viscoat and 500 mL BSS Plus is 5 times that of Ocucoat and Ringer's solution.

[A new model of induced ocular hyperpressure using the minipig]

PURPOSE

To characterize a new animal model of moderate chronic hyperpressure obtained by obstruction of the iridocorneal angle (ICA) in the minipig.

METHODS

Intraocular hyperpressure was induced in one eye (left) using an injection of methylcellulose (4%) in the anterior chamber of six healthy adult minipigs. Intraocular pressure (IOP) was measured before injection and at D+60 and D+180. The clinical condition thus created was regularly assessed with the following procedures: fundus photography, electroretinography (ERG) to evaluate retinal function, scanning laser ophthalmoscopy (SLO) angiography to measure the arteriovenous filling times (AVFT). Optical microscopy was also performed to evaluate iridocorneal angle and inner retinal layers.

RESULTS

In all instances the injection produced a significant increase in the IOP accompanied by a mydriasis, as well as a significant increase in the AVFT and reduction (abolition in some cases) in the i-wave of the ERG. Fundus examination also revealed a blurred aspect and reduction in the calibre of the retinal blood vessels. Similarly, all experimental eyes showed, at optical microscopy, obstruction of the ICA as well a significant loss of of retinal ganglion cells.

CONCLUSION

Our results suggest that the above pathophysiological processes, triggered by the induced hyperpressure, share many similarities with human chronic open-angle glaucoma. Consequently, our model, which is very easy to create, could be used to test new therapeutic agents such as neuroprotective drugs.

Hydroxypropyl methylcellulose: A better submucosal fluid cushion for endoscopic mucosal resection

BACKGROUND

Formation of a submucosal fluid cushion has become integral to endoscopic mucosal and polyp resection. Solutions available for injection into the submucosa of the GI tract create short-lasting submucosal fluid cushions or are costly. The feasibility, durability, and histologic response to submucosal fluid cushions created by injection of hydroxypropyl methylcellulose were studied in the esophagus of pigs.

METHODS

Thirty-six esophageal submucosal fluid cushions created with hydroxypropyl methylcellulose were studied in 12 animals divided in 2 groups of 6 animals each. In Group I, 18 submucosal fluid cushions were created by submucosal injection of hydroxypropyl methylcellulose followed by tattooing. In Group II, 18 submucosal fluid cushions were created by submucosal injection of hydroxypropyl methylcellulose, with sites marked by an endoscopically placed suture. In all cases, the duration of the submucosal fluid cushion was measured. After 7 days, submucosal fluid cushion sites were assessed by EGD, necropsy, and histologic evaluation.

RESULTS

The mean submucosal fluid cushion duration was 36 minutes (3-45 minutes) and 38 minutes (5-45 minutes) for, respectively, Groups I and II. EGD and necropsy after 1 week showed normal-appearing mucosa at the site of all submucosal fluid cushions in both groups. Some Group I animals additionally had nodules at the tattoo sites. Histologic assessment demonstrated minimal alterations in 33 of 36 (92%) submucosal fluid cushion sites and localized mild inflammatory reaction in 3 of 36 (8%). In Group I, 8 of 18 (44%) tattoo sites exhibited a significant inflammatory reaction, including 3 abscesses.

CONCLUSIONS

Hydroxypropyl methylcellulose creates a long-lasting submucosal fluid cushion with minimal tissue reaction and should be considered a low-cost option for creating submucosal fluid cushions. The use of tattooing with carbon black should be carefully considered when histologic study is required to assess potential inflammatory tissue responses to an invasive technique or instillation of foreign material in the GI tract.

Pharmacological management of obesity

Obesity is a major chronic health problem in adults. It is a complex, multifactorial disorder characterised by excess accumulation of adipose tissue. It is associated with a number of complications including cardiovascular disease, hypertension, type 2 diabetes, dyslipidaemia and cancer. A weight loss in the order of 5-10% is associated with clinically meaningful reductions with respect to all comorbidities. Diet and exercise has been the cornerstone of weight management therapy, but this approach has limitations, especially for weight maintenance. Previous drugs used in obesity had serious side effects including valvular heart disease. However, recent drugs like orlistat and sibutramine have been rigorously tested and proven safe. Orlistat, a lipase inhibitor, inhibits absorption of dietary fat by approximately 30%. Taken with a hypocaloric diet, it produces and maintains clinically meaningful weight loss. Sibutramine is a centrally-acting agent which enhances satiety and thermogenesis by inhibiting serotonin and noradrenaline re-uptake. It is appropriate for patients who are unable to lose weight by lifestyle modification.

Double-layered mucoadhesive tablets containing nystatin

The objective of this work was to design a mucoadhesive tablet with a potential use in the treatment of oral candidosis. A 2-layered tablet containing nystatin was formulated. Lactose CD (direct compression), carbomer (CB), and hydroxypropylmethylcellulose (HPMC) were used as excipients. Tablets were obtained through direct compression. Properties such as in vitro mucoadhesion, water uptake, front movements, and drug release were evaluated. The immediate release layer was made of lactose CD (100 mg) and nystatin (30 mg). The CB:HPMC 9:1 mixture showed the best mucoadhesion properties and was selected as excipient for the mucoadhesive polymeric layer (200 mg). The incorporation of nystatin (33.3 mg) in this layer affected the water uptake, which, in turn, modified the erosion front behavior. Nystatin showed a first-order release. The polymeric layer presented an anomalous kinetic (n = 0.82) when this layer was individually evaluated. The mucoadhesive tablet formulated in this work releases nystatin quickly from the lactose layer and then in a sustained way, during approximately 6 hours, from the polymeric layer. The mixture CB:HPMC 9:1 showed good in vitro mucoadhesion. A swelling-diffusion process modulates the release of nystatin from this layer. A non-Fickian (anomalous) kinetic was observed.

A comparison of the effect of refresh plus and bion tears on dry eye symptoms and ocular surface health in myopic LASIK patients

PURPOSE

To compare the effect of artificial tears (0.5% carboxymethylcellulose [CMC] in lactate buffer vs. 0.3% hydroxypropyl methylcellulose and 0.1% dextran in bicarbonate buffer [HPMC]) on the preservation of ocular surface health in postoperative laser in situ keratomileusis (LASIK) patients.

METHODS

Nonrandomized, comparative, retrospective analysis of a clinical database. Patients (n = 519; 985 eyes) had undergone LASIK in a single refractive surgery center performed by a single surgeon using the same LASIK technique (Nidek EC5000 laser and ACS keratome). Patients (n = 254) were given CMC (Refresh Plus/Cellufresh) or HPMC (Bion Tears) four times per day and were evaluated at presurgery, week 2, and months 1, 3, and 6. Included patients were those with complete clinical data through the month I follow-up visit.

RESULTS

There were no significant between-group differences in any baseline variable. Following LASIK, fewer CMC patients (n = 111) reported dry eye symptoms than HPMC patients (n = 143) at the week 2 (13.5% vs. 30.8%; P = .001) and month 1 (19.8% vs. 38.5%; P = .001) follow-up visits. CMC patients also had significantly lower mean ocular surface staining scores than HPMC patients at week 2 (0.09 vs. 0.30; P = .015) and month 1 (0.05 vs. 0.28; P = .008). There were no between-group differences in either measure at months 3 or 6 (P < or = .728).

CONCLUSIONS

CMC was more effective than HPMC in controlling dry eye symptoms and preserving ocular surface health in the immediate postoperative period in myopic post-LASIK patients, possibly due to the greater muco-adhesive properties of CMC. These results warrant further investigation as to the most effective postoperative LASIK lubricant.

Acute scleral thinning after pterygium excision with intraoperative mitomycin C: a case report of scleral dellen after bare sclera technique and review of the literature

PURPOSE

To describe a patient with scleral dellen after pterygium excision with intraoperative mitomycin C.

METHODS

Case report and MEDLINE review of the medical literature on scleral dellen after bare sclera technique.

RESULTS

A 48-year-old man had a left nasal pterygium excised by the bare sclera technique with intraoperative mitomycin C. Eight days after surgery, the patient noticed a small black spot in the bare sclera area with mild irritation. Slit-lamp examination revealed a focal area of extreme thinning, centered on the nonepithelialized bare sclera, surrounded by edematous conjunctiva. The ciliary body was visible through the thin and dry scleral lesion. After topical lubricant therapy, the scleral lesion appeared normal thickness and white in color 3 days later. Therapy was continued until the sclera epithelialized.

CONCLUSIONS

Scleral dellen is an early postoperative complication of bare sclera technique owing to delayed conjunctival wound closure. Hydration of the thinned sclera will rapidly thicken it. However, medical therapy should be continued until the surrounding conjunctiva has flattened and the sclera has epithelialized. Surgical wound closure is an alternative management and may be the way to prevent scleral dellen formation after bare sclera technique. All patients after bare sclera surgery should be followed up until the conjunctival wound has healed. If delayed healing is found, frequent artificial tears, patching, or surgical intervention is necessary.

Corneal toxicity secondary to inadvertent use of benzalkonium chloride preserved viscoelastic material in cataract surgery

AIMS

To study the long term toxic effects of intraocular benzalkonium chloride (BAC).

METHODS

19 patients exposed to intraocular BAC preserved viscoelastic during cataract surgery in February 1999 developed severe striate keratopathy immediately postoperatively. 16 patients, including two who underwent penetrating keratoplasty, were studied in the period April to June 2000. Ocular symptoms, visual acuity, biomicroscopy, intraocular pressure, dilated funduscopy, specular endothelial microscopy, and corneal pachymetry findings were recorded. The corneal and iris specimens of the two patients who underwent keratoplasty were studied by light, transmission, and scanning electron microscopy.

RESULTS

Six males and 10 females, aged 64-98 years, were studied 14-16 months postoperatively. All patients were symptomatic. 12 patients had best corrected visual acuity of 6/12 or better and four patients of between 6/18 and 6/60. Five patients had corneal epithelial oedema and 11 had Descemet's membrane folds. The central corneal thickness, 620 (SD 71) microm, in affected eyes was significantly higher (p<0.005, two tailed paired t test) than that of the contralateral eyes, 563 (SD 48) microm. The endothelial cell density was significantly lower (p<0.0001, two tailed paired t test) in affected eyes: 830 (SD 280) cells/mm2 v 2017 (SD 446) cells/mm2. The mean average cell area was significantly higher in the BAC treated eyes: 1317 (SD 385) microm2 v 521 (SD 132) microm2. There was no significant difference in the coefficient of variation of cell size between the two eyes (p=0.3, two tailed paired t test). Two corneal specimens displayed morphological features of bullous keratopathy and other non-specific abnormalities. Extracellular melanosomes were present in a portion of the iris of one case.

CONCLUSION

BAC is toxic to the corneal endothelium when used intraocularly, leading to severe striate keratopathy. This cleared in most cases but left varying degrees of residual stromal thickening in all eyes. If penetrating keratoplasty is required the results are excellent.

[Application of 2% clindamycin cream in the treatment of bacterial vaginosis and valuation of methylcellulose gel containing the complex of Chitosan F and PVP k-90 with lactic acid as carrier for intravaginally adhbited medicines in the cases of pregnancies with the symptoms of preterm delivery]

OBJECTIVES

There are many reports informing about the connection between BV and the increased risk of preterm delivery. The reason of self-concession and reversion of BV after having executed an efficient treatment has not yet been properly explained.

DESIGN

The aim of this work was the clinical valuation of the 2% Clindamycin cream in the treatment of BV and of the methylcellulose gel containing the complex of Chitosan F and PVP K-90 with lactic acid as a carrier for intravaginally adhbited medicines in the cases of pregnancies with the symptoms of a preterm delivery.

MATERIAL AND METHODS

The research comprised 145 pregnant between 24-34 week of pregnancy, hospitalised because of the symptoms of a preterm menace delivery. In the case of the detection of BV, a 10-day therapy using intravaginal cream containing 2% Clindamycin was executed. In the cases not qualified as BV, the methylcellulose gel containing the complex of Chitosan F and PVP K-90 with lactic acid has been intravaginally adhibited for 10 days.

CONCLUSIONS

1. Application of 2% Clindamycin cream is an efficient method of the treatment of bacterial vaginosis. 2. Methylcellulose gel containing lactic acid combined with the complex of Chitosan F and PVP K-90 allows a persistent maintenance of the correct pH of vagina. 3. Methylcellulose gel, because of its physico-chemical properties similar to physiological mucus, is a universal carrier for intravaginally adhibited medicines.

Prevention of the ingress of a known virulent bacterium into the root canal system by intracanal medications

Contamination of the root canal system by persistent, enteric bacteria via leakage through interim restorations has been well documented. This in vitro study evaluated the ability of interappointment medications to prevent contamination of the root canal system by Enterococcus faecalis. Coronally unsealed, medicated tooth roots fixed in a closed system were contaminated daily with a standardized, aerobic, broth culture of E. faecalis. Four medications were evaluated (n = 15): group A, calcium hydroxide/methylcellulose paste; group B, camphorated parachlorophenol/calcium hydroxide paste; group C, 1% chlorhexidine/methylcellulose gel; and group D, calcium hydroxide points. The mean number of days to contamination as indicated by turbidity in the closed system was the following: group A, 37; group B, 46; group C, 16; group D, 5; and a positive control (no medication), 3. A one-way analysis of variance with a Scheffe post hoc test (p = 0.05) detected significant differences in effectiveness with A and B superior to C and D, and C superior to D.

Phacoemulsification of brunescent and black cataracts

PURPOSE

To evaluate the efficacy and safety of a step-by-step, chop in situ, lateral separation technique to remove brunescent and black cataracts.

SETTING

Iladevi Cataract and IOL Research Center, Ahmedabad, India.

METHODS

In this prospective study conducted between May 1997 and June 1998, 167 consecutive eyes were divided into 2 groups: Group 1, brunescent cataract (n = 123), and Group 2, black cataract (n = 44). Preoperative assessment included axial length (AL), slitlamp examination, corneal pachymetry, tonometry, and specular microscopy. During phacoemulsification performed by a single surgeon, a step-by-step, chop in situ, lateral separation technique was used to divide the nucleus. Intraoperatively, hydroxypropyl methylcellulose 2% was used and irrigation was by balanced salt solution (BSS). Postoperatively, all eyes were assessed at 1, 7, 30, 90, 180, and 360 days. The results were evaluated using regression analysis, the chi-square test, and the Student t test.

RESULTS

The mean follow-up was 14.4 months (range 6 to 35 months) in Group 1 and 13.0 months (range 6 to 32 months) in Group 2. The AL was significantly greater in Group 2 (P =.02). Corticapsular adhesions were present in 17.82% in Group 1 and 31.82% in Group 2. The mean cumulative dissipated energy was 2.03 and 3.12, respectively (P =.0005). Wound site thermal injury occurred in 16 eyes (13.01%) in Group 1 and 4 eyes (9.09%) in Group 2. No serious intraoperative or postoperative complications were noted. One day postoperatively, the mean rise in intraocular pressure was 1.76 mm Hg in Group 1 and 4.15 mm Hg in Group 2 (P =.012), and transient corneal edema was present in 24.40% and 34.10%, respectively. At 1 month, the endothelial cell loss was 10.06% in Group 1 and 9.22% in Group 2.

CONCLUSION

The step-by-step, chop in situ, lateral separation technique was effective and did not produce serious complications such as zonulysis or posterior capsule rupture. However, the incidence of wound site thermal injury and endothelial cell loss was greater than after emulsification of standard cataracts.

Conditioning of hydrogel lenses by a multipurpose solution containing an ocular lubricant

PURPOSE

The addition of the ocular lubricant hydroxypropyl methylcellulose (HPMC) to a multipurpose contact lens solution conditions the hydrogel lens surface. This investigation reports the clinical benefits to contact lens wearers and the improved physical properties of the solution with HPMC added.

METHODS

One-hundred forty-seven subjects wearing a variety of hydrogel lenses used a multipurpose solution with and without addition of HPMC and were assessed for product comfort and preference. In the laboratory, conditioning by HPMC was demonstrated in fluid coating, dynamic contact angle, uptake of fluid on hydrogel lenses, and release of HPMC from lenses after soaking.

RESULTS

Lens wearers reported the multipurpose solution with HPMC more comfortable, including measures relating to maintaining lens moisture over time. The multipurpose solution with HPMC produced a thicker and longer-lasting layer of fluid on hydrogel lenses and other plastics than other multipurpose solutions. HPMC was found to adsorb to both group 1 and 4 lens materials and release gradually, with detectable amounts releasing from the lens beyond 12 hours.

CONCLUSIONS

The conditioning properties of the multipurpose solution with HPMC produce improved wetting of lenses and enhanced lens wearing comfort. Binding of HPMC to the lens surface and subsequent time-release is the probable mechanism for these benefits.

Semi-solid albumin solder improved mechanical properties for laser tissue welding

BACKGROUND AND OBJECTIVE

A semi-solid albumin solder formulated with hydroxypropylmethylcellulose (HPMC) was designed to improve the characteristics of liquid and solid solders.

STUDY DESIGN/MATERIALS AND METHODS

Acute tensile strengths were determined on canine small bowel in vitro by using liquid 50% bovine serum albumin (BSA), semi-solid 48% BSA with HPMC, and solid 60% BSA solder. Long-term healing of liquid and semi-solid solders, compared with a suture control, was evaluated in a porcine skin model, with tensile strength as well as histologic findings obtained on postoperative day 7.

RESULTS

Acutely, semi-solid solder demonstrated a significantly (P < 0.05) higher tensile strength when compared with liquid or solid solder. At 7 days, HSA semi-solid and BSA semi-solid had significantly (P < 0.05) higher tensile strength than suture control; however, no differences were seen for liquid or solid solder groups. No differences in histology were appreciable between any of the solder groups in a porcine skin model.

CONCLUSION

Acutely and at 7 days, semi-solid solder was stronger than 50% liquid albumin with better handling characteristics.

High-molecular-weight hydroxypropylmethylcellulose taken with or between meals is hypocholesterolemic in adult men

Hydroxypropylmethylcellulose (HPMC) is a food gum that shares certain characteristics, such as high viscosity, with soluble fibers. In this trial, the safety and cholesterol-lowering efficacy of HPMC consumed with and between meals was evaluated in free-living male volunteers with mild-to-moderate hypercholesterolemia. After a 14-d baseline period, men (n = 51) with LDL cholesterol between 3.36 and 4.91 mmol/L and triglycerides <3.95 mmol/L were randomly assigned to consume 5.0 g/d HPMC in 240 mL of orange drink, taken either with or between meals, for a 2-wk treatment period. In the Between Meals group, total cholesterol was reduced by 8.0% vs. baseline in wk 1 of treatment (P < 0.05) and 5.1% in wk 2 (P < 0.01). LDL cholesterol concentrations fell by 12.0 and 7.7% (P < 0.01). In the With Meals group, reductions were 9.5 and 8.3% for total cholesterol, and 12.5 and 12.8% for LDL cholesterol (wk 1 and 2, respectively, P < 0.01). In both groups, HDL cholesterol decreased by approximately 5% during wk 1 of treatment (P < 0.01), but the wk 2 concentrations were not significantly different from baseline. There were no significant differences between groups in lipid responses, although there was a trend for a smaller LDL cholesterol-lowering effect during wk 2 of treatment in the Between Meals group (P < 0.06). Gastrointestinal-related adverse experiences (mostly mild) were twice as common among participants who ingested HPMC with meals (P < 0.05). These results suggest that HPMC has a lipid-lowering effect, which may be more consistent when taken with meals.