Cesium Carbonate Promoted Direct Amidation of Unactivated Esters with Amino Alcohol Derivatives.

Cesium carbonate promoted direct amidation of unactivated esters with amino alcohols was developed without the use of transition-metal catalysts and coupling reagents. This method enabled the synthesis of several serine-containing oligopeptides and benzamide derivatives with yields up to 90%. The methodology proceeds under mild reaction conditions and exhibits no racemization for most naturally occurring amino acid substrates. The reaction demonstrates good compatibility with primary alkyl and benzyl esters and broad tolerance for a range of amino acid substrates with nonpolar and protected side chains. The hydroxy group on the amine nucleophile was found to be critical for the reaction to be successful. A likely mechanism involving cesium coordination to the substrates enabling the subsequent proximity-driven acyl transfer was proposed. The practicality of this approach was demonstrated in the preparation of a biologically active nicotinamide derivative in a reasonable yield.

Robust laser speckle recognition system for authenticity identification.

This paper proposes a laser speckle recognition system for authenticity verification. Because of the unique imperfection surfaces of objects, laser speckle provides identifiable features for authentication. A Gabor filter, SIFT (Scale-Invariant Feature Transform), and projection were used to extract the features of laser speckle images. To accelerate the matching process, the extracted Gabor features were organized into an indexing structure using the K-means algorithm. Plastic cards were used as the target objects in the proposed system and the hardware of the speckle capturing system was built. The experimental results showed that the retrieval performance of the proposed method is accurate when the database contains 516 laser speckle images. The proposed system is robust and feasible for authenticity verification.

Lamellar sclerectomy augmented XEN gel stent glaucoma surgery.

PURPOSE: To describe a surgical technique to optimize XEN gel stent position and its outflow. METHODS: A small 1- to 1.5-mm square lamellar sclerectomy was created at the external tip of the XEN gel stent implant. The lamellar scleral tissue, served as a patch graft, was secured at the gel stent insertion site. RESULTS: Four sequential, unselected, patients with failed primary XEN gel stent surgeries underwent bleb revisions with the technique described. These four patients achieved unmedicated intraocular pressures between 10 and 12 mmHg and a favourable bleb morphology despite repeated mitomycin C applications at 6 months. CONCLUSION: Lamellar sclerectomy with auto-scleral graft augmented XEN gel stent surgery deliver successful short-term outcomes without major complications observed.

1-year outcomes of the Xen45 glaucoma implant.

OBJECTIVES: To describe the 12-month outcomes of the Xen45 glaucoma stent. METHODS: Non-comparative retrospective study of all cases who underwent Xen glaucoma surgery in April 2017 or earlier and completed 12 months of follow-up. The primary outcome measures were intraocular pressure (IOP) reduction and number of glaucoma medications at 12 months postoperatively. The secondary outcome measures were surgical complications and the success rate of surgery at 1 year. Success rate was defined according to the multiple IOP thresholds of 15 mmHg, 18 mmHg, and 21 mmHg with all requiring a drop of 20% and no additional glaucoma surgery. Revision or needling of the Xen conjunctival bleb was not considered to constitute a surgical failure. RESULTS: Sixty-eight eyes were included in the study. Mean IOP dropped from 22.1 mmHg preoperatively to 14.8 mmHg at 12 months, a 33% drop (p < 0.0001). Mean number of glaucoma medications reduced from 2.9 preoperatively to 1.1 at 12 months (p < 0.0001). In total, 54.4% of cases were back on glaucoma medications by 12 months. Success rate varied from 32.4% when defined as IOP ≤ 15 mmHg and ≥ 6 mmHg and ≥ 20% reduction without medications to 70.6% when defined as IOP ≤ 21 mmHg and ≥ 6 mmHg and ≥ 20% reduction with or without medications. Thirty cases (44.1%) required bleb needling or surgical revision. CONCLUSIONS: The Xen45 is effective at reducing IOP and glaucoma medication use at 12 months postoperatively. Patients considering this procedure should be warned that by 12 months postoperatively there is a significant chance of requiring postoperative bleb intervention and glaucoma drops.

Vertigo - part 2 - management in general practice.

BACKGROUND: Vertigo is a common clinical problem managed by general practitioners. OBJECTIVE: This article focuses on the acute management of a vertigo attack, specific management of conditions causing vertigo, and the long term management issues associated with chronic vertigo. DISCUSSION: Supportive treatment, antiemetic and vestibular blocking agents help relieve an acute vertigo attack, however the prolonged use of such medications is not recommended. Specific treatments for various conditions causing vertigo are available, however, the majority of patients are managed symptomatically. The patient's ability to drive safely should be carefully assessed according to Austroads guidelines and advice from an ear, nose and throat surgeon should be sought when in doubt. There is evidence to support the efficacy of vestibular rehabilitation programs for unilateral peripheral vestibular disorder and these programs should be considered. A simple program including patient education and home based exercises can be sufficient.

Vertigo - part 1 - assessment in general practice.

BACKGROUND: Vertigo is a common and diagnostic challenge faced by clinicians. OBJECTIVE: This article discusses the assessment of patients with vertigo. DISCUSSION: The clinical assessment aims to: establish the presence of true vertigo, differentiate between vertigo of central or peripheral origins, and to evaluate the need for urgent investigations and referrals. Peripheral causes of vertigo are more common, but central causes such as transient ischaemic attack or stroke should always be considered and ruled out appropriately. Presence of syncope excludes the peripheral causes of vertigo. Vertigo in the elderly population is likely to be multifactorial and warrants careful evaluation. Online videos of the head impulse test and the Dix-Hallpike manoeuvre are valuable as these tests are of great diagnostic value. Audiological testing and neuroimaging can provide further information to guide patient management.

Orbital exenterations: an 18-year experience from a single head and neck unit.

BACKGROUND: To review the outcomes of the patients who undergo orbital exenteration for malignancy. METHODS: A retrospective review of patients who underwent orbital exenteration performed at Royal Prince Alfred and Concord Hospitals between 1990 and 2008. RESULTS: A total of 38 patients were identified. The most common malignancies were squamous cell carcinoma (14 cutaneous and five mucosal origin), basal cell carcinoma (12 cutaneous) and melanoma (five patients). Orbital invasion was the main indication for orbital exenteration. Additional procedures were performed in 29 (76%) patients at the time of exenteration, including craniotomies in eight patients and maxillectomy in 15 patients. Flap reconstructions were required in 35 (92%) patients, including 33 free flap repairs and two local flap repairs. Post-operative complications included cerebrospinal fluid leak (16%) and wound-related complications (13%). The disease-specific survival rate was 97% at 1 year and 92% at 5 years. The local control rate was 83% at 1 year and 55% at 5 years. Fifty per cent of patient mortality and 63% of local recurrence occurred within the first post-operative year. CONCLUSIONS: In this series, locoregional control and survival were high, suggesting that aggressive surgical measures such as orbital exenteration are not unreasonable in well-selected patients. Free flap reconstruction is a reliable reconstructive technique which may reduce major complications. The first post-operative year is the most important period when monitoring for recurrence.

Pharmacotherapeutic efficacy of preservative-free intravitreal triamcinolone acetonide.

Preservative-free formulations of triamcinolone acetonide have recently been introduced to the market over concerns of local toxicity of the vehicle and preservatives, including benzyl alcohol in the original formulation, which was not designed for intraocular use. The pharmacokinetics and pharmacodynamics of intravitreal triamcinolone (IVTA) are discussed. The therapeutic effects of IVTA include improvement of visual acuity and reduction of macular edema. However, ongoing treatment is usually required to maintain its effects. The efficacy of IVTA for both FDA-approved and 'off-labeled' indications is reviewed. Elevation of intraocular pressure and cataract formation are the two major side effects of IVTA; these are manageable but require close long-term follow-up. More studies are required to determine the optimal dosage and treatment frequency in different posterior segment disease.