Superficial keratectomy and 360º conjunctival flap for bullous keratopathy in a dog: a case report

Relata-se o caso ocorrido em um cão, da raça Pinscher, com dois anos de idade e histórico de desconforto no olho direito. O olho esquerdo havia sido enucleado por outro profissional, por apresentar os mesmos sinais, cujo tratamento clínico instituído não lograra êxito. O valor do teste da lágrima de Schirmer encontrava-se aumentado e identificou-se diminuição da pressão intraocular à tonometria de aplanação. Observaram-se, à biomicroscopia, edema corneal profuso e ceratocone, e o teste da fluoresceína foi negativo. Gonioscopia e oftalmoscopia não lograram fornecer dados relevantes dadas as condições da córnea. Diagnosticou-se ceratite bolhosa. Optou-se pelo tratamento cirúrgico, que fora realizado em duas etapas: 1- ceratectomia superficial e flap conjuntival de 360º; 2- ceratectomia superficial para devolver transparência à córnea. Transcorridos 30 dias da segunda ceratectomia superficial, o flap de terceira pálpebra foi desfeito. Observou-se conjuntivalização do quadrante nasal superior da córnea, córnea clara no eixo visual e retorno da visão.

The treatment of pterygium

The treatment of pterygium is still quite controversial, with various treatments being advocated in the scientific literature. Unfortunately, there are very few well-conducted controlled clinical trials of treatments. However, years of anecdotal and noncontrolled studies have confirmed that some methods, such as bare scleral closure, are no longer acceptable in the treatment of pterygium and that other methods are likely to be more useful. In the future it will be important to develop a grading system, and surgeons will need to be conservative in the treatment of pterygium until such time as a single treatment provides a lower recurrence rate and complication rate.

Review of treatment of pterygium in Queensland: 10 years after a primary survey

Purpose: To assess the practices in pterygium removal as a follow-up study to a similar project 10 years ago, in order to compare the current trends with those noted a decade ago. Methods: A survey was sent to all practising ophthalmologists in Queensland (100). Results: Eighty-seven of the 100 ophthalmologists undertook pterygium surgery with no change in indications for removal, grading or anaesthesia compared to 10 years ago. Nearly half of the ophthalmologists varied their surgical technique from eight commonly used methods according to the individual patient. More than half the respondents used a swinging conjunctival flap and 29% used simple excision leaving the area bare for primary pterygia, although nearly one-quarter of the ophthalmologists added adjunctive therapies such as beta irradiation or mitomycin. For recurrent pterygia, one-third of ophthalmologists preferred adjunctive therapies, and 57% used an autoconjunctival transplant. Conclusion: There has been no consistent trend in surgical removal of pterygia with a significant number of primary pterygia still removed using bare scleral closure.

Natural latex graft in lamellar and penetrating sclerectomies in rabbits

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aspectos clínicos do enxerto conjuntival 360° e do implante da membrana amniótica criopreservada no tratamento de úlceras de córnea em cães

To evaluate the clinical application of implant of the canine cryopreserved amniotic membrane (DMEM plus DMSO 1:1) and 360° conjunctival flap in the treatment of progressive corneal ulceration. 10 dogs of the different breeds, males and females, aging four months to four years old with deep corneal ulceration and different clinical progression were divided in two groups: G1=360° conjunctival graft (n=5) and G2=implant of amniotic membrane, sutured at the edge of the ulcer with epithelial side facing up, associated with the third eyelid flap (n=5). The comparative analysis between groups was: complications, blepharospasm, ocular secretion, corneal vascularization, epithelial defect and corneal opacification in six moments (first emergency care, surgery and 3, 7, 15 and 30 days of postoperative). Without epithelial defect was evaluated quality of the scar. It was used score scale for subjective to qualify of the ocular signs. In G1, it was observed the non-adherence of the conjunctival graft to the ulcer (n=2), dehiscence of the suture (n=2), anterior synechia (n=2) and intense chemosis (n=1). In G2, it was not observed these complications. It was not significant difference between the groups to others ocular parameters, but it was different among the start and end moments of the same groups (ocular secretion, corneal vascularization, epithelial defect). The corneal opacity was more intense in G1. According to the clinical results, the cryopreserved amniotic membrane implant proved to be as effective in the corneal ulceration in comparison to the 360° conjunctival flap, because probably, the membrane promoted a trophic support for epithelialization, anti-inflamatory effect associated with important to the end result phenotype.

Implante da membrana amniótica criopreservada em associação ou não com transplante de limbo no tratamento de úlceras profundas de córnea em cães

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Pig eye trabeculectomy - a wet-lab teaching model

Purpose A teaching model for trabeculectomy is described using pig eyes prepared in formalin. Method The model enables trainee surgeons to practice various aspects of tissue handling required for successful trabeculectomy including the construction of a fornix-based conjunctival flap, scleral flap with buried releasable sutures, and water-tight conjunctival closure. Results Exposure to the necessary skills required to perform trabeculectomy surgery can be improved by the use of wet laboratory practice. Conclusions Trabeculectomy surgery experience is becoming more limited as fewer procedures are being performed due to the efficacy of recent medications. Wet laboratories will become an increasingly important aspect of a comprehensive ophthalmology training programme.

Comparative Analysis of the Influence of Perichondrium on Conjunctival Epithelialization on Conchal Cartilage Grafts in Eyelid Reconstruction: Experimental Study in Rabbits

Background: Although the role of cartilage grafts in reconstruction of the posterior eyelid lamella is well established, spontaneous conjunctival epithelialization on such grafts has yet to be fully proven. The aim of this study was to perform a comparative analysis of the influence of perichondrium on conjunctival epithelialization over conchal cartilage grafts used in eyelid reconstruction in rabbits. Methods: The posterior lamellae of 100 lower eyelids from 50 rabbits were reconstructed with autogenous grafts of conchal ear cartilage. In the right eyelids, cartilage was grafted with the perichondrium in direct contact with the eyeball, and the left eyelids were reconstructed in a similar manner but using cartilage grafts without perichondrium. The animals were killed after 1, 2, 3, 4, and 5 weeks, and their lower eyelids were analyzed macroscopically and histologically. Results: The percentage difference in conjunctival epithelialization on the cartilage with perichondrium and that without perichondrium was 11.41 percent in the first week of the experiment, 13.64 percent in the second week, 18.69 percent in the third week, 10.38 percent in the fourth week, and 6.17 percent in the fifth week. The average percentage conjunctival epithelialization in the eyelids reconstructed with a cartilage graft with perichondrium was significantly higher throughout the 5 weeks of the experiment than in the eyelids reconstructed with cartilage without perichondrium (p < 0.0002). Conclusion: It was found that the perichondrium had an important role in conjunctival epithelialization in eyelids reconstructed with a cartilage graft in the present study. (Plast. Reconstr. Surg. 123: 55, 2009.)

Uso do 5-fluorouracil no intra-operatório da cirurgia do pterígio

Objetivo: Avaliar a efetividade e as complicações com a aplicação do 5- fluorouracil (5-FLU) no intra-operatório da cirurgia do pterígio. Método: Foram avaliados 28 olhos de 26 indivíduos quanto ao tipo e tamanho do pterígio, cirurgias prévias e a resposta ao tratamento cirúrgico (no 7º , 21º , 60º e 90º dia de pós-operatório). Logo após a exerese do pterígio, aplicou-se 5-FLU (25 mg/ml) no leito cirúrgico, durante cinco minutos; a seguir, realizou-se a técnica de deslizamento de retalho conjuntival. Resultados: A maioria dos pacientes tinha mais de 50 anos de idade e apresentava pterígio primário (70,0%), grau II (60,7%), do tipo involutivo (60,7%). No pós-operatório observaram-se: isquemia (10,7%), deiscência da conjuntiva (7,1%), ceratite (3,5%), conjuntivite (3,5%) e recidiva da lesão em 1 olho (3,5%).Conclusão: O 5-FLU se mostrou droga segura e efetiva na prevenção das recidivas, podendo ser usado como coadjuvante no tratamento do pterígio para prevenir recidivas.

Sliding wear of weld layers with application to cane mill shaft rebuilding

Three welding procedures used to rebuild worn shafts in sugar cane mills were analysed: two submerged arc welding processes and one flux cored arc welding (FCAW) process. Sliding wear tests were in accordance with ASTM G 77 standard, using rings of welding material, blocks of bronze SAE 67, and oil as lubricant. The worn surfaces of rings and blocks were analysed by scanning electron microscopy to determine the wear mechanisms. High contact pressure, high operating temperature, and low relative speed were applied in sliding wear tests to match the conditions in sugar cane mills. Transferred material and evidence of adhesive junctions were detected. Additionally, hardened fragments produced abrasive grooves on the worn surfaces. The welding deposits that presented strong adhesion on the worn surface showed higher mass loss than the materials that presented more abrasive characteristics. Plastic mechanical properties were measured and related to the mass loss. The tested materials presented similar hardness but different yield stress and hardening coefficient. A relationship between wear, strain hardening coefficient, and yield stress was found. The welding deposit that presented the highest hardening coefficient showed the highest mass loss, with evidence of severe adhesion on the worn surface.

Low-Level Laser Therapy on the Viability of Skin Flap in Rats Subjected to Deleterious Effect of Nicotine

Objective: The purpose of this study was to evaluate the effect of 830-nm laser in blocking the action of nicotine on the viability of skin flap. Background data: The authors have analyzed the deleterious effect of cigarette smoke or nicotine on the skin flap alone with evidence of increased skin necrosis in the flap. Materials and methods: Twenty-four Wistar-albino rats were divided into three groups of eight animals each: Group 1 (control), subjected to a surgical technique to obtain a flap for cranial base, laser irradiation simulation, and a subcutaneous injection of saline; Group 2, similar to Group 1, with subcutaneous injection of nicotine (2mg/kg/day) for a period of 1 week before and 1 week after surgery; and Group 3, similar to Group 2, with skin flaps subjected to a lambda 830-nm laser irradiation. The laser parameters used were: power 30 mW, beam area 0.07cm(2), irradiance 429 mW/cm(2), irradiation time 84 sec, total energy 2.52J, and energy density 36J/cm(2). The laser was used immediately after surgery and for 4 consecutive days, in one point at 2.5 cm of the flap cranial base. The areas of necrosis were examined by two macroscopic analyses: paper template and Mini-Mop (R). The pervious blood vessels were also counted. Results: The results were statistically analyzed by ANOVA and post-test contrast orthogonal method (multiple comparisons), showing that the laser decreased the area of necrosis in flaps subjected to nicotine, and consequently, increased the number of blood vessels (p < 0.05). Conclusions: The laser proved to be an effective way to decrease the area of necrosis in rats subjected to nicotine, making them similar to the control group.

Effect of Low-Level Laser Therapy on Malondialdehyde Concentration in Random Cutaneous Flap Viability

Objective: The aim of this study was to assess the effects of 830 and 670 nm laser on malondialdehyde (MDA) concentration in random skin-flap survival. Background Data: Low-level laser therapy (LLLT) has been reported to be successful in stimulating the formation of new blood vessels and activating superoxide-dismutase delivery, thus helping the inhibition of free-radical action and consequently reducing necrosis. Materials and Methods: Thirty Wistar rats were used and divided into three groups, with 10 rats in each one. A random skin flap was raised on the dorsum of each animal. Group 1 was the control group; group 2 received 830 nm laser radiation; and group 3 was submitted to 670 nm laser radiation. The animals underwent laser therapy with 36 J/cm(2) energy density immediately after surgery and on the 4 days subsequent to surgery. The application site of the laser radiation was 1 point, 2.5 cm from the flap's cranial base. The percentage of the skin-flap necrosis area was calculated 7 days postoperative using the paper-template method, and a skin sample was collected immediately after as a way of determining the MDA concentration. Results: Statistically significant differences were found between the necrosis percentages, with higher values seen in group 1 compared with groups 2 and 3. Groups 2 and 3 did not present statistically significant differences (p > 0.05). Group 3 had a lower concentration of MDA values compared to the control group (p < 0.05). Conclusion: LLLT was effective in increasing the random skin-flap viability in rats, and the 670 nm laser was efficient in reducing the MDA concentration.

Thermodynamic approaches in sliding wear: a review

In this paper, a review of the thermodynamic approaches of sliding wear is presented. These approaches are divided into the friction energy dissipation, the energy balance and the entropy production. A concise and critic account of the approaches is discussed, remarking their relative strength and weakness in explaining the phenomena occurring in the sliding wear.

Mild and severe wear of steels and cast irons in sliding abrasion

This paper presents the results obtained in pin-on-disk test apparatus using glass and alumina as abrasive materials, showing the rates and mechanisms of abrasive wear of 1070 and 52100 steels, and ductile and white cast irons. The test conditions were selected in order to obtain wear rates that correspond to mild and severe abrasion, using different metal hardness-to-abrasive hardness ratios(H/H(A)) and 0.2 or 0.06 mm abrasive grains. The use of bulk Vickers hardness, instead of microhardness, allows a better description of the different abrasion regions. Under severe abrasion, the microcutting mechanism of wear prevailed together with friction coefficients larger than 0.4. On the other hand, when relatively soft abrasives are tested, indentation of abrasive particles followed by its fragmentation, and a creation of a thin deformed layer were the main damage mechanisms, with the friction coefficient lying below 0.4. The abrasive particle size under mild regime is able to change the wear rates in an order of magnitude. (C) 2009 Elsevier B.V. All rights reserved.

Influence of hardness of the harder body on wear regime transition in a sliding pair of steels

In the unlubricated sliding wear of steels the mild-severe and severe-mild wear transitions have long been investigated. The effect of system inputs such as normal load, sliding speed, environment humidity and temperature, material properties, among others, on those transitions have also been studied. Although transitions seem to be caused by microstructural changes, surfaces oxidation and work-hardening, some questions remain regarding the way each aspect is involved. Since the early studies in sliding wear, it has usually been assumed that only the material properties of the softer body influence the wear behavior of contacting surfaces. For example, the Archard equation involves only the hardness of the softer body, without considering the hardness of the harder body. This work aims to discuss the importance of the harder body hardness in determining the wear regime operation. For this, pin-on-disk wear tests were carried out, in which the disk material was always harder than the pin material. Variations of the friction force and vertical displacement of the pin were registered during the tests. A material characterization before and after tests was conducted using stereoscopy and scanning electron microscopy (SEM) methods, in addition to mass loss, surface roughness and microhardness measurements. The wear results confirmed the occurrence of a mild-severe wear transition when the disk hardness was decreased. The disk hardness to pin hardness ratio (H(d)/H(p)) was used as a criterion to establish the nature of surface contact deformation and to determine the wear regime transition. A predominantly elastic or plastic contact, characterized by H(d)/H(p) values higher or lower than one, results in a mild or severe wear regime operation, respectively. (c) 2009 Elsevier B.V. All rights reserved.