PVA-PEG physically cross-linked hydrogel film as a wound dressing: experimental design and optimization

The development of hydrogel films as wound healing dressings is of a great interest owing to their biological tissue-like nature. Polyvinyl alcohol/polyethylene glycol (PVA/PEG) hydrogels loaded with asiaticoside, a standardized rich fraction of Centella asiatica, were successfully developed using the freeze–thaw method. Response surface methodology with Box–Behnken experimental design was employed to optimize the hydrogels. The hydrogels were characterized and optimized by gel fraction, swelling behavior, water vapor transmission rate and mechanical strength. The formulation with 8% PVA, 5% PEG 400 and five consecutive freeze–thaw cycles was selected as the optimized formulation and was further characterized by its drug release, rheological study, morphology, cytotoxicity and microbial studies. The optimized formulation showed more than 90% drug release at 12?hours. The rheological properties exhibited that the formulation has viscoelastic behavior and remains stable upon storage. Cell culture studies confirmed the biocompatible nature of the optimized hydrogel formulation. In the microbial limit tests, the optimized hydrogel showed no microbial growth. The developed optimized PVA/PEG hydrogel using freeze–thaw method was swellable, elastic, safe, and it can be considered as a promising new wound dressing formulation.     

Correlations between tear fluid and aqueous humor cytokine levels in bullous keratopathy

PurposeTo evaluate the correlation between tear fluid and aqueous humor (AqH) cytokine levels in eyes with bullous keratopathy (BK) and with normal endothelium.MethodsThis prospective consecutive case-series study included 71 eyes of 71 patients: 31 eyes with BK, 18 eyes with non-BK corneal diseases, and 22 eyes with uncomplicated cataract (healthy controls). Total protein and cytokine (interleukin [IL]-1α, IL-1β, IL-4, IL-6, IL-8, IL-10, MIP-1α, MIP-1β, monocyte chemotactic protein [MCP]-1, E-selectin, P-selectin, soluble intercellular adhesion molecule [sICAM]-1, and IP-10) levels in the tear fluid and AqH were measured using multiplex beads immunoassay. The correlations between tear and AqH cytokine levels were assessed.ResultsThe AqH protein level was significantly higher in BK eyes (1.09 ± 0.08 mg/mL) than in non-BK (0.63 ± 0.11, P = 0.0004) and healthy control (0.62 ± 0.06, P = 0.0002) eyes. The tear total protein and IL-4 levels were significantly higher in the BK group compared to healthy controls (P = 0.0374 and 0.0032, respectively). The AqH IL-8 and sICAM-1 levels were significantly higher in the BK group compared to controls (P = 0.0001 and 0.0083, respectively). In BK eyes, the tear IL-4 level was significantly correlated with the MCP-1(r = 0.563, P = 0.001) and total protein (r = 0.589, P = 0.001) AqH levels. The tear IL-8 level was significantly correlated with the MCP-1(r = 0.598, p = 0.001) and IL-4 (r = 0.781, p < 0.0001) AqH levels in BK eyes. However, no significant correlations were found between tear and AqH cytokine levels in non-BK and healthy controls eyes.ConclusionsThe tear cytokine levels are correlated with those of AqH only in BK, but not in non-BK and healthy controls.     

环境烟草烟雾对小鼠泪膜功能和角膜上皮组织结构的影响

目的　探讨环境烟草烟雾（enviromental tobacco smoke,ETS）对小鼠泪膜功能和角膜上皮组织结构的影响。方法　选取SPF级c57BL雄性小鼠12只,随机分为对照组和ETS干预组,每组6只。对照组不进行ETS干预,ETS干预组进行ETS干预,每天2次,一次30 min,干预12周。在干预前及干预后对各组小鼠进行泪膜功能检测,包括泪膜破裂时间、荧光素染色(FL)评分;干预后摘取小鼠角膜组织,行HE染色,在光学显微镜下观察小鼠角膜上皮结构变化情况。结果　干预12周后,对照组泪膜破裂时间和FL评分与干预前相比,差异均无统计学意义(均为P>0.05);而ETS干预组泪膜破裂时间较干预前明显缩短,FL评分较干预前明显增加,差异均有统计学意义（均为P<0.05)。ETS干预组干预12周后泪膜破裂时间较对照组明显缩短,FL评分较对照组明显增加,差异均有统计学意义(均为P<0.05);两组干预前泪膜破裂时间和FL评分差异均不明显（均为P>0.05）。FL染色结果显示:干预12周后,对照组小鼠角膜上皮完整,角膜染色呈阴性;ETS干预组整个角膜上皮荧光素着染区域明显增加,呈点片状。HE染色结果显示:干预12周后,对照组未见角膜上皮层数的改变,厚度也基本未变,基底细胞仍为单层柱状上皮细胞,表层上皮较完整;ETS干预组可见角膜上皮细胞层数增多,厚度增加,细胞排列紊乱,表层上皮细胞有损失及脱落,角膜表面不光滑。干预前对照组小鼠上皮细胞为（5±1）层,干预后基本不变;ETS干预组干预后为（7±1）层;干预后两组上皮细胞层数比较差异有统计学意义（P＜0.05）。结论　ETS会影响小鼠泪膜功能,损伤小鼠角膜上皮的组织结构。     

Randomized masked trial of the clinical efficacy of MGO Manuka Honey microemulsion eye cream for the treatment of blepharitis

PurposeTo assess the clinical efficacy of a novel MGO Manuka Honey microemulsion (MHME) eye cream for the management of blepharitis.MethodsFifty-three participants (32 females, 21 males; mean ± SD age, 60 ± 12 years) with clinical signs of blepharitis were enrolled in a prospective, investigator-masked, randomized, paired-eye trial. The MHME eye cream (Manuka Health New Zealand) was applied to the closed eyelids of one eye (randomized) overnight for 3 months. Visual acuity, ocular surface characteristics, symptoms and tear film parameters were assessed at baseline, day 30, and day 90. Eyelid swab microbiology cultures were evaluated at baseline and day 90.ResultsBaseline measurements did not differ between treated and control eyes (all p > 0.05). Significant reductions in SANDE and SPEED symptomology scores were detected in treated eyes on days 30 and 90 (all p < 0.05), while clinical improvements in non-invasive tear film breakup time, lipid layer thickness, and inferior lid wiper epitheliopathy were observed on day 90 (all p < 0.05). Following the 3-month treatment period, ocular Demodex, Corynebacterium macginleyi, Propionibacterium acnes, and Staphylococcus epidermidis load decreased significantly in treated eyes (all p ≤ 0.001). There were no changes in visual acuity during the 90-day period (all p > 0.05), and no major adverse events were reported.ConclusionTopical overnight application of the MHME eye cream effected significant improvements in ocular surface symptomology, tear film stability and lipid layer thickness, and reduced lid margin staining, ocular Demodex and bacterial load. The favourable clinical efficacy and tolerability profile suggests promise for the MHME eye cream as a treatment for blepharitis management.Trial registration numberACTRN12616000539437.     

Evaluation of use of essential fatty acids in topical ophthalmic preparations for dry eye

PurposeEssential fatty acids (EFAs) as dietary supplements are used in treating dry-eye for reducing inflammation at the ocular surface. Their topical application in eye drops to deliver fatty acid (FA) directly to the ocular surface requires thorough investigation. Being lipids in nature EFAs can interact with tear lipids and affect tear stability. This study aimed at investigating the biophysical interactions of EFAs with Meibomian lipids.MethodsRheology of mixtures of Human Meibomian lipids with EFAs (LA-linoleic acid, ALA-alpha-linolenic acid), OA (oleic acid), and GLA (gamma-linolenic acid) was studied using Langmuir trough technology on an artificial tear solution at the ocular surface temperature. Pressure-area profiles were used to determine compressibility and elasticity of the mixed films.ResultsLA enhanced spreading of Meibomian lipids and increased their compressibility and elasticity which can be beneficial for tear stability. ALA condensed Meibomian lipids film with less elasticity deemed unfavourable for tear stability. OA expanded Meibomian lipids but decreased elasticity at high compressions making films less stable. GLA had little or no favourable effect on tear stability. Higher concentrations of FAs made films less stable.ConclusionsEFAs or OA in topical ophthalmic preparations can affect spread and stability of the tear film lipid layer. Rheology of mixed films should be tested using Langmuir trough technology to determine suitable type and amount of a lipid additive for therapeutic eye drops. In topical applications, the omega-6 LA (not omega-3 FA) at low concentrations (20 mol%) can be beneficial for enhancing tear stability in dry eye patients.     

Randomised double-masked placebo-controlled trial of the cumulative treatment efficacy profile of intense pulsed light therapy for meibomian gland dysfunction

PurposeTo assess long-term cumulative treatment effects of intense pulsed light (IPL) therapy in meibomian gland dysfunction (MGD).MethodsEighty-seven symptomatic participants (58 female, mean ± SD age, 53 ± 16 years) with clinical signs of MGD were enrolled in a prospective, double-masked, parallel-group, randomised, placebo-controlled trial. Participants were randomised to receive either four or five homogeneously sequenced light pulses or placebo treatment to both eyes, (E-Eye Intense Regulated Pulsed Light, E-Swin, France). Visual acuity, dry eye symptomology, tear film parameters, and ocular surface characteristics were assessed immediately before treatment on days 0, 15, 45, 75, and four weeks after treatment course completion on day 105. Inflammatory and goblet cell function marker expression, and eyelid swab microbiology cultures were evaluated at baseline and day 105.ResultsSignificant decreases in OSDI, SPEED, and SANDE symptomology scores, and meibomian gland capping, accompanied by increased tear film lipid layer thickness, and inhibited Corynebacterium macginleyi growth were observed in both treatment groups (all p < 0.05). Sustained clinical improvements occurred in both treatment groups from day 75, although significant changes from day 45, in lipid layer quality, meibomian gland capping, OSDI and SANDE symptomology, were limited to the five-flash group (all p < 0.05).ConclusionsIPL therapy effected significant improvements in dry eye symptomology, tear film lipid layer thickness, and meibomian gland capping in MGD patients. Five-flash IPL treatment showed superior clinical efficacy to four-flash, and an initial course of at least four treatments is suggested to allow for establishment of sustained cumulative therapeutic benefits prior to evaluation of overall treatment efficacy.Trial registration numberACTRN12616000667415.     

网塞加平片行无张力疝修补术276例治疗体会

目的探讨网塞加平片无张力疝修补术在腹股沟疝中的临床应用。方法回顾性分析我院2009年1月至2013年5月276例腹股沟疝无张力修补临床资料,全部采用网塞加平片无张力修补术。结果 276例全部治愈,4⁷ d出院。结论网塞加平片行无张力修补术治疗腹股沟疝疗效良好,操作简易、创伤小、恢复快、无显著并发症。     

A novel multivariate approach using science-based calibration for direct coating thickness determination in real-time NIR process monitoring

This study demonstrates an approach, using science-based calibration (SBC), for direct coating thickness determination on heart-shaped tablets in real-time. Near-Infrared (NIR) spectra were collected during four full industrial pan coating operations. The tablets were coated with a thin hydroxypropyl methylcellulose (HPMC) film up to a film thickness of 28 μm. The application of SBC permits the calibration of the NIR spectral data without using costly determined reference values. This is due to the fact that SBC combines classical methods to estimate the coating signal and statistical methods for the noise estimation. The approach enabled the use of NIR for the measurement of the film thickness increase from around 8 to 28 μm of four independent batches in real-time. The developed model provided a spectroscopic limit of detection for the coating thickness of 0.64 ± 0.03 μm root-mean square (RMS). In the commonly used statistical methods for calibration, such as Partial Least Squares (PLS), sufficiently varying reference values are needed for calibration. For thin non-functional coatings this is a challenge because the quality of the model depends on the accuracy of the selected calibration standards. The obvious and simple approach of SBC eliminates many of the problems associated with the conventional statistical methods and offers an alternative for multivariate calibration.     

胰腺影像检查读片思路和注意事项

文章详细阐述了胰腺疾病影像学检查的选择、读片思路、良恶性胰腺肿块的鉴别,如何结合临床进行影像学诊断等,为社区医生正确读片提供思路。     

Changes in Optical Parameters of SiO2:TiO2 Films Obtained by Sol-Gel Method Observed as a Result of Thermal Treatment

The research focused on materials having potential applications in technology of planar evanescent wave sensors. Four samples of binary SiO₂:TiO₂ thin films having different titania content were manufactured through the sol-gel method and dip-coating technique on polished silicon substrates. The samples were subjected to repeated heating/cooling protocols. Simultaneously, their optical parameters were monitored by spectroscopic ellipsometry as they evolved under varying temperature. Subsequent analysis confirmed linear dependence of refractive index on titania content, at least in vis-NIR wavelengths, as well as a low value of the thermal expansion coefficient. It was shown that the thickness of SiO₂:TiO₂ films decreased as a result of annealing processes, which may be a consequence of reduced porosity.