Philip T.H. Lam

Viral clearance and inflammatory response patterns in adults hospitalized for pandemic 2009 influenza A(H1N1) virus pneumonia.

BACKGROUND Little is known about the virological and inflammatory responses of severe pandemic 2009 influenza A(H1N1) virus pneumonia during antiviral treatment. METHODS In a prospective observational study, we recruited consecutive adults hospitalized with confirmed pandemic 2009 H1N1 infection during a 16-week period. Nasopharyngeal aspirate and non-respiratory samples (blood, stool and urine) were collected at presentation, and serial nasopharyngeal flocked swabs (NPFS) and tracheal aspirates (TA) were collected after initiating oseltamivir treatment for quantitative viral RNA assay, using real-time reverse transcriptase-PCR. Serial plasma samples were collected for cytokine/chemokine assay using cytometric bead array. Patients with severe pneumonia (lung infiltrates and hypoxaemia) were compared to those with milder illnesses. RESULTS A total of 66 patients were studied (mean age 43 ±20 years); 28 (42%) developed severe pneumonia, of whom 10 (15%) required intubation. Severe pneumonia was associated with older age, dyspnoea, delayed presentation >2 days from onset, extrapulmonary virus detection (13-28%) and higher viral concentration despite late-presentation (multiple linear regression, β=0.94, 95% confidence interval 0.15-1.74; P=0.02). Patients with severe pneumonia exhibited slow viral clearance with oseltamivir treatment, particularly in the lower respiratory tract (median [interquartile range] durations of RNA positivity after antiviral initiation were NPFS 6.0 days [3.0-8.0], TA 11.0 days [7.8-14.3] versus milder illness group NPFS of 2.0 days [1.0-3.0] days; P<0.01). High viral load in lower respiratory tract despite upper-tract RNA negativity and viral rebound after stopping treatment were noted in some patients. H275Y mutation was absent. High plasma levels of interleukin (IL)-6, CXCL-8 (IL-8), CCL2 (monocyte chemoattractant protein-1) and soluble tumour necrosis factor receptor-1 were observed, which correlated with the extent and progression of pneumonia in hospital. CONCLUSIONS In severe 2009 H1N1 pneumonia, viral clearance is slow with treatment, particularly in the lower respiratory tract. A more sustained antiviral regime appears warranted.

Descemet Stripping Endothelial Keratoplasty: Effect of the Surgical Procedure on Corneal Optics

PURPOSE To determine the changes in corneal optical performance after posterior lamellar corneal transplantation. DESIGN Retrospective case series. METHODS The anterior segment in four eyes of four patients who underwent Descemet stripping endothelial keratoplasty (DSEK) with cataract extraction and intraocular lens (IOL) implantation were imaged with the Visante anterior segment optical coherence tomography [OCT] (Carl Zeiss Meditec, Dublin, California, USA). The curvature of the posterior surface of the donor graft was compared with that of the host cornea, and corneal thickness was measured. RESULTS All eyes had a hyperopic refractive error after surgery. The posterior corneal curvature after surgery was more than that before surgery. Average preoperative keratometry was 43.4 diopters (D), and after surgery, it was 42.8 D using keratometry. However, when the postsurgical corneal power was calculated using the Gaussian optics method, the average value was 40.8 D. CONCLUSIONS The addition of a donor corneal graft to the posterior surface of decompensated corneas may lessen the effective optical power of the cornea and may have implications for IOL power calculations in these eyes.

Clinical and virological course of infection with haemagglutinin D222G mutant strain of 2009 pandemic influenza A (H1N1) virus

BACKGROUND Aspartic acid to glycine substitution (D222G) of haemagglutinin subunit (HA1) was associated with adverse outcomes in 2009 pandemic influenza A (H1N1) infections. OBJECTIVES To characterize the virological profile and antiviral response of patients infected with the HA1 D222G mutant. STUDY DESIGN Sixty-three adults admitted for pandemic influenza in Hong Kong were tested for D222G mutation by direct sequencing. Nasopharyngeal viral concentration on presentation was measured by real-time PCR to evaluate shedding from the upper respiratory tract. Serial upper and lower respiratory tract specimens were monitored to determine preferential tropism and document virological response to treatment. RESULTS The frequency of D222G infection was 17.4% among cases with severe pneumonia, and 26.7% among cases requiring intensive care. Altogether, four sporadic D222G cases spread across the first and second waves in Hong Kong were detected. A significant association between D222G infection with severe pneumonia (100% vs. 32.2%, P=0.015) and intensive care admission (100% vs. 18.6%, P=0.002) was observed. D222G was associated with lower concentrations of virus in the upper respiratory tract compared to wildtype, but persisted in the lower respiratory tract at high concentrations, despite clearance from the upper respiratory tract following antiviral treatment. CONCLUSIONS These observations suggest that D222G can arise de novo, sheds less virus from the upper respiratory tract and may be less transmissible, but more pneumotropic and more resistant to antiviral treatment. D222G is associated with a higher chance of developing critical disease. Lower respiratory tract specimen is needed for a reliable detection of this mutant.

Topical 0.03% tacrolimus ointment in the management of ocular surface inflammation in chronic GVHD.

Topical 0.03% tacrolimus ointment in the management of ocular surface inflammation in chronic GVHD

Prospective study on the safety and efficacy of combined conjunctival rotational autograft with intraoperative 0.02% mitomycin C in primary pterygium excision.

Purpose: To describe the novel use of combined conjunctival rotational autograft (CRA) and intraoperative 0.02% mitomycin C (MMC) in the treatment of primary pterygium and to evaluate its safety and efficacy. Methods: Prospective interventional case series comparing with historical controls was conducted. Patients with primary pterygium underwent pterygium excision, MMC was applied to the scleral bed after the surface conjunctiva was harvested, and the CRA was sutured back with a 180-degree rotation. Patients were followed for a minimum of 1 year. Results: Sixty-seven eyes from 67 patients participated in the study, of which 31 (46.3%) were men and 36 (53.7%) were women. The mean age was 58 ± 10.6 years, (range 36-79 years). There were 2 recurrences (3%), one occurring at month 3 and the other at month 9. Compared with historical controls, CRA-MMC resulted in significantly fewer recurrences than MMC alone (P = 0.005) when adjusted for age and was equally effective when compared with limbal-conjunctival autografts. The main postoperative problem was graft injection, which was noted in 41 eyes (61%) at 1 year. Conclusions: To the best of our knowledge, this was the first study on the combined use of CRA and MMC in the treatment of primary pterygium. CRA with MMC was found to be effective in the prevention of recurrence. Although injection remained as a cosmetic concern, it was a safe alternative to limbal-conjunctival autograft in cases where mobilizing autologous conjunctival tissue would not be feasible.

A prospective study on trypan blue capsule staining under air vs under viscoelastic

AimTo compare the safety and effectiveness of trypan blue capsule staining under air vsunder viscoelastic.MethodsA total of 52 consecutive patients planned for phacoemulsification of white mature cataract were randomly assigned to trypan blue staining under air or under viscoelastic. Perioperative changes in best-corrected visual acuity (BCVA), central corneal thickness (CCT), and endothelial cell density (ECD) were compared between the two groups. The differences in operating and phacoemulsification times, staining pattern, and complications between the two groups were also recorded.ResultsPhacoemulsification of white mature cataract was performed in 50 (96%) eyes. The median preoperative BCVA was hand movement. No significant differences in the baseline characteristics were found between the two groups. At 3 months after phacoemulsification, the median BCVA improved to 0.8. The mean CCT returned to preoperative level by 1 month postoperatively and the mean ECD loss was 11.9% 3 months postoperatively. No significant differences in median BCVA, mean phacoemulsification and operation times, mean CCT, and mean ECD were found between the two groups.ConclusionsTrypan blue staining of the anterior lens capsule under air or under viscoelastic were similarly effective and safe methods for the phacoemulsification of white mature cataract.

Randomized controlled trial on the safety of intracameral cephalosporins in cataract surgery.

Objective: To compare the safety profiles of intracameral cephalosporins in cataract surgery. Patients and methods: In this controlled trial, 129 patients were randomized to one of four groups to receive 1 mg of one of three cephalosporins – cefazolin, cefuroxime, or ceftazidime, or normal saline – given intracamerally during cataract surgery. Central endothelial cell density (ECD) and retinal center point thickness (CPT) were determined by specular microscopy and ocular coherence tomography, respectively, before and at 3 months after surgery. Results: There were no statistical significant differences in the changes of ECD and CPT between eyes receiving intracameral cephalosporin and control. Conclusion: The use of intracameral cefazolin, cefuroxime, or ceftazidime (1 mg in 0.1-mL solution) at the time of cataract surgery had no significant effect on ECD and CPT postoperatively.

Randomised controlled trial on the effectiveness of lidocaine gel vs tetracaine drops as the sole topical anaesthetic agent for primary pterygium surgery

PurposeTo determine the effectiveness of lidocaine 2% gel vstetracaine 1% drops in primary pterygium surgery.MethodsThis was a prospective, randomised controlled trial. Forty consecutive patients who had primary pterygium underwent surgical excision of primary pterygium and mitomycin C. Patients were randomised into two groups. Group 1 received tetracaine 1% drops and solcoseryl eye gel (Solco Basel AG, Switzerland). Group 2 received xylocaine 2% gel (lidocaine hydrochloride 2% gel, AstraZeneca, Sweden) topically and normal saline drops 0.9%. Additional tetracaine drops were given to patients who experienced pain preoperatively. The primary outcome was the pain experienced during and after surgery. Immediately after the operation, pain and discomfort scores were assessed by the patients and doctor using a 10-point linear analogue scale. The stages of the operation were divided into the following: stage 1—first incision, stage 2—pterygium body excision, stage 3—conjunctival suturing, and stage 4—immediate postoperative after patching.ResultsThere was no statistically significant difference in the mean pain scores experienced during pterygium excision (3.03±2.35 for the lidocaine group and 3.98±2.18 for the tetracaine group). However, for stage 3, there was a statistically significant difference in mean pain scores experienced during closure (P=0.03) (0.47±0.84 for the lidocaine gel group and 1.43±1.66 for the tetracaine group), with patients of group 2 experienced less pain. The mean number of additional drops required by the eyes in lidocaine gel group was also significantly (0.16±0.11) less than the tetracaine group (0.67±0.09, P=0.001).ConclusionsTopical administration of lidocaine 2% gel or tetracaine 1 % drops are both effective anaesthetic agents for primary pterygium surgery and mitomycin C. However, lidocaine gel is superior to tetracaine eye drops and its application is more convenient with a less frequent application and a sustained duration of action.

Randomized clinical trial of the efficacy and safety of tropicamide and phenylephrine in preoperative mydriasis for phacoemulsification

Purpose: To compare the mydriatic effect and safety between different concentrations of tropicamide and phenylephrine in preoperative mydriasis for phacoemulsification.

Safety and Efficacy of Micro-Incisional Cataract Surgery with Bimanual Phacoemulsification for White Mature Cataract

Background: To evaluate the safety and efficacy of micro-incisional cataract surgery (MICS) with bimanual phacoemulsification for the management of white mature cataract. Methods: Twenty-five eyes in 25 patients with mature cataract were prospectively recruited to undergo MICS with bimanual phacoemulsification. Serial changes in best-corrected visual acuity (BCVA), central corneal thickness (CCT) and endothelial cell density (ECD) were compared using the Wilcoxon signed-rank test. Results: MICS was successfully performed in 24 (96%) of the 25 eyes, with 1 eye requiring conversion to extracapsular cataract extraction due to radial tear during continuous curvilinear capsulorhexis. The median preoperative BCVA was hand movement. On day 1 postoperatively, the median BCVA improved to 0.6 (p < 0.001 compared with baseline). All patients had BCVA of 0.6 or better at 3 months after surgery (p < 0.001 compared with baseline). The mean increase in CCT at day 1 and week 1 postoperatively was 11.5 and 7.1%, respectively. The change in mean CCT was no longer significant at month 3 postoperatively (p = 0.82). The mean reduction in ECD at 3 months postoperatively was 7.8% (p = 0.037). None of the patients developed any postoperative complications. Conclusions: MICS with bimanual phacoemulsification appeared to be a promising alterative for the management of white mature cataract.