Silver from polyurethane dressing is delivered by gradient to exudate, tissue, and serum of patients undergoing negative-pressure wound treatment.

OBJECTIVE: This study aimed to evaluate the distribution and concentration of silver eluted from silver-coated polyurethane dressing (V.A.C. GranuFoam Silver Dressing; KCI, San Antonio, Texas) in vitro and in patients undergoing negative-pressure wound therapy (NPWT). DESIGN: This was a descriptive study of the effect of silver-coated polyurethane dressing in patients undergoing NPWT. PARTICIPANTS: Six patients with infected wounds undergoing NPWT using silver-coated polyurethane dressing. INTERVENTIONS: To evaluate silver release in vitro, the authors soaked dressing fragments in water and human serum for different lengths of time and performed atomic absorption spectroscopy. For patient evaluation, the authors obtained exudate, serum, and wound tissue at different time points from 6 patients undergoing NPWT and measured silver levels by atomic absorption and dispersed x-ray spectroscopy. MAIN RESULTS: Silver from the dressing was immediately released in vitro at a rate 3 times greater in serum than in water. In vivo, silver was delivered to wound exudate at rates 102 to 104 times greater than in corresponding serum. Few surface silver deposits were detected in treated tissue. CONCLUSION: The high concentration of silver found in wound exudate reflects not only the affinity for silver in serum components and wound fluids, but also that most silver ions are not distributed systemically in the patient; instead, they are transported by the vacuum created by therapy.

[Ultrastructure of the anterior capsule of the lens in different pathologies]. / Ultraestructura de la cápsula anterior del cristalino en diversas patologías.

BACKGROUND: We undertook this study to compare the ultrastructural analysis of capsules of normal lenses (phacorefractive procedures) and those of other types of cataracts also such as senile cataracts, with trans-surgical staining. METHODS: Capsule samples were obtained by circular continuous capsulorhexis during phacoemulsification procedures. All samples were fixed and conventionally processed for light- and transmission-electron microscopy analysis. RESULTS: Seventeen analyzed samples were grouped as follows: a) phacorefractive (n = 2), b) senile cataract (n = 3); c) senile diabetic (n = 3), d) pseudoexfoliation syndrome (n = 3); e) stained with trypan blue (n = 2), f) indocyanine green (n = 2), and g) gentian violet (n = 2). According to morphological analysis, all samples of cataract demonstrated lacunae zones between epithelial cells. Filamentous annular bodies were found near the epithelium in capsule of senile cataracts. Senile diabetic cataract samples showed more abnormalities in epithelial morphology; specifically we found conformation of two or three layers of epithelial cells. Samples stained with trypan blue showed a regular basal membrane and minor loss of epithelial cells than other trans-surgical stain techniques. CONCLUSIONS: After an exhaustive medical literature search, we published the first report about the observation of filamentous annular bodies near the epithelium in capsules of senile cataracts. Additionally, it is important to note the presence of stratification of the epithelium at the anterior pole of capsules from diabetic patients.

[Peripheral hereditary neuropathies: Charcot-Marie-Tooth types 1 and 2]. / Neuropatías periféricas hereditarias: Charcot-Marie-Tooth tipos 1 y 2.

OBJECTIVE: We report 14 cases of patients with Charcot-Marie-Tooth types 1 (CMT) and type 2 (CMT2). The objective of this study was to determine the diagnostic value of structural studies of peripheral nerve and striated muscle biopsies and to discuss correlations with clinical symptoms and electrophysiologic findings. MATERIAL AND METHODS: Nerve and muscle biopsies were obtained and processed according to standards methods for transmission electron microscopy. Diagnosis of CMT was based on clinical electrophysiologic findings. RESULTS: Our results demonstrated that myelinated fibers showed moderate-to- severe demyelinization and remyelinization, folding complex, tomacula formations, and presence of moderate vacuoles into myelin. The axonal cytoskeleton shows an important decrease of neurofilaments and microtubules in myelinated and unmyelinated nerves. Striated muscle showed different degenerative changes in Z disc. One important finding was presence of crystals inclusions in mitochondrion. In 11 cases, it was possible to find relevant changes in mitochondria-like hyperplasia. In this study, we had four cases with > 20 years of evolution; these cases showed relevant degenerative changes in nerve and muscle. Nerves presented great demyelination with damage in cytoskeleton of the axon, while fibers of muscle had necrosis and hyalinization. CONCLUSIONS: According to our results, it is possible to distinguish morphologically CMT subtypes, due to the fact that in CMT2 we found a 50% decrease of filaments and microtubules that were reduced in myelinic axons; this finding does not occur in CMT1.

[Quantitative analysis of worn and torn particles in periprosthetic tissue of hip and knee with scanning electron microscopy]. / Análisis de partículas de desgaste en tejido periprotésico de cadera y rodilla con microscopia electrónica de barrido.

BACKGROUND: Arthroplasty is successful because biocompatible material is available, but its lifespan decreases due to inadequate fixation, mechanical wear and tear, or biological loss caused by osteolysis. This last is a tissue response to wear particles of the implanted material localized in the bone--prosthesis interface. We undertook this study to present the morphological analysis and characterization of the metal wear particles (MWP) in the periprosthetic tissue of patients with prosthetic loosening. METHODS: Interface tissue was studied in 63 patients with prosthetic loosening and was processed with the conventional histological technique, and tissues with wear and tear particles were subjected to chemical element determination by energydispersive X-ray analysis. RESULTS: Composition of the prosthesis placed in patients contained Cr-Co (30.2%), stainless steel (34.9%), Cr-Co/stainless steel (12.7%) and Ti (22.4%). Cellular response caused by wear and tear particles was classified according to three types. MWP were identified in only 19 membranes. Particle presence or absence was not significantly associated with clinical characteristics of the patient and worn and torn methacrylate or polyethylene particles. Periprosthetic membranes that showed MWP were the ones of older patients with a longer average time of graft use and those with severe necrosis. CONCLUSIONS: No patients experienced infection at the same time with MWP probably because they were treated for prosthetic septic loosening; consequently, it is less probable that they were recruited in a cross-sectional study such as the present one.

[Results of the experimental repair of osteochondral lesions in a pig model using tissue engineering]. / Resultados en la reparación experimental de lesiones osteocondrales en un modelo porcino mediante ingeniería de tejidos.

OBJECTIVE: To repair experimental osteochondral knee lesions in pigs using tissue engineering. MATERIAL AND METHODS: Eight 40-kg pigs underwent surgery. Cartilage and periosteal biopsies of their control knee were taken. Cartilage and periosteal cells were independently isolated, cultured and seeded in biodegradable PGA and PLA polymers that were fixed on the bottom of an osteochondral defect in the pig's experimental knee, with bioabsorbable Mitek implants. Four months later the pigs were sacrificed and the knees were analyzed with nuclear magnetic resonance imaging (NMRI), macroscopic assessment, histology, electron microscopy (EM), scanning electron microscopy (SEM) and SEM element analysis. RESULTS: All the defects were filled with cartilage-like tissue according to the NMRI evaluation and the visual examination. Hyaline-like cartilage was obtained in 3 defects and fibrocartilage in 5. The EM showed chondrocytes in the repair tissue. The SEM showed appropriate integration to the bone and the surrounding tissue. SEM element analysis showed sulphurized matrix attached to the bone with calcium and phosphates as predominant elements. DISCUSSION: Tissue engineering enabled the production of tissues similar to normal ones. The polymer fixation system was effective.

Estudio de la consolidación ósea en rata por microscopía electrónica de barrido ambiental / Study on the osseous consolidation in rat by environmental scanning electron microscopy

The environmental scanning electron microscope (ESEM) has been recently applied to orthopedics, for which a study was performed on the modes of operation of this electron microscope. Optimal conditions were determined to obtain the best topographic image and to perform chemical analysis by X-ray dispersion during the process of bone consolidation. Fifteen male Wistar rats were used, grouped in three per each experimental day. Tibia l fracture was provoked and a Kirschner wire was positioned. Rats were euthanized 0 (control), 7, 14, 21 and 28 days after surgery. According to the results, the best bone image was observed with retrodispersed electrons under high vacuum. In the chemical element determination lower variation coefficients were obtained under low vacuum for carbon and calcium; for phosphorus, under high vacuum, and in environmental mode, for magnesium, sodium, potassium and iron. In the process of bone consolidation, calcium levels in cortical bone diminished compared to controls, while the calcified bone callus was observed until day 14. Phosphorus concentration increased with time, in both cortical bone and bone callus. Magnesium presented a peak on day 14, and decreased drastically until day 28. Sodium rose continuously until day 28. The study of the chemical composition of bone by the ESEM is optimal in the environmental mode, since values of the elements present in lesser concentrations (1%) showed a lower variation coefficient. In bone consolidation process, calcium and phosphorus levels were found at a ratio of 2:1.

La aplicación del microscopio electrónico de barrido ambiental (ESEM) en ortopedia no se había desarrollado hasta ahora, por lo que se realizó un estudio sobre los modos de operación del microscopio electrónico; así se determinaron las condiciones óptimas de obtención de la mejor imagen topográfica y del análisis químico por dispersión de rayos X durante el proceso de la consolidación ósea. Para ello se utilizaron 15 ratas macho de la cepa Wistar, que se agruparon en tres por cada día experimental, se les produjo una fractura en la tibia y se les colocó un alambre Kirschner; se efectuó eutanasia a los 0 (testigo), 7, 14, 21 y 28 días después de la cirugía. De acuerdo con los resultados, la mejor imagen del hueso se observó con electrones retrodispersados en alto vacío. En la determinación de elementos químicos se obtuvieron los menores coeficientes de variación en bajo vacío para carbono y calcio; en alto vacío, para fósforo, y en modo ambiental, para magnesio, sodio, potasio y fierro. En el proceso de la consolidación ósea los niveles de calcio en hueso cortical disminuyeron en comparación con el testigo, mientras que el callo óseo calcificado se observó hasta el día 14. La concentración de fósforo incrementó con el tiempo, tanto en hueso cortical como en callo óseo. El magnesio presentó un pico el día 14 y bajó drásticamente hasta el día 28; por último, el sodio subió de manera sostenida hasta el día 28. El mejor modo de estudiar la composición química del hueso en el ESEM es el modo ambiental, pues los valores de los elementos que están en menor concentración (1%) presentaron coeficiente de variación más bajo. En el proceso de consolidación ósea, los niveles de calcio y fósforo se encontraron en relación 2:1.

Efecto de la metionina de zinc en el casco del equino: una evaluación por microscopía electrónica de barrido ambiental / Effect of zinc methionine on the equine hoof: an evaluation by environmental scanning electron microscopy

The hoof is a relatively simple structure, mainly constituted by keratin, a highly sulfated protein, that provides hardness to the hoof and certain elasticity to support the weight and distribute the impact's intensity on the hoof. The hoof needs to have an adequate quality to be able to carry out these functions and that requires a good nutrition based on proteins, vitamins and minerals. Minerals constitute 4% of body weight and they are conformed by macrominerals (calcium, phosphorus, sodium, chloride, potassium, magnesium and sulfur) and microminerals (selenium, iodine, copper and zinc). Zinc participates in hoof formation while inducing keratin production. Its diet deficiency causes problems to the corneous tissue such as: thin and friable hooves, and fissures on the wall. Zn++ must be ingested in chelated form, as zinc methionine, to be adequately absorbed. The diet of seven horses was supplemented with 5.4 g/day/horse of zinc methionine for a period of six months. Samples were obtained from the wall level and transverse cuts were done; before and after the treatment, its morphology and contents of minerals (Mg++, Cl, S, Ca++, Na++, K+, P, Si, Fe++, Cu++,Zn++) were analyzed in the environmental scanning electron microscope equipped with an X ray disperser. It was observed that the morphology presented a better constitution and compactness of the tubular and intratubular horns in the medium stratum, as well as a substantial increment of zinc (32.9%) and sulfur (68.4%), which suggests an increase in keratin and better structure of the hoof.

El casco es una estructura relativamente sencilla, constituida por queratina, proteína bastante sulfatada, que provee al casco de dureza y cierta elasticidad para soportar el peso y distribuir la intensidad del impacto en el casco. Para este fin, se necesita que el casco tenga una calidad adecuada, que requiere de buena nutrición basada en proteínas, vitaminas y minerales. Los minerales constituyen 4% del peso corporal y se conforman en macrominerales (calcio, fósforo, sodio, cloro, potasio, magnesio y azufre) y microminerales (selenio, yodo, cobre y zinc). El zinc participa en la formación del casco al inducir la producción de queratina. Su deficiencia en la dieta causa problemas al tejido córneo, como cascos delgados, friables y fisuras en la pared. Para que el Zn++ sea absorbido adecuadamente, es necesario que sea ingerido en forma quelada como metionina de zinc. La dieta de siete caballos fue complementada con 5.4 g/día/caballo de metionina de zinc por un periodo de seis meses. Se obtuvieron muestras a nivel de la muralla y se realizaron cortes transversales; antes y después del tratamiento, se analizó su morfología y contenido de minerales (Mg++, Cl-, S, Ca++, Na++, K+, P, Si, Fe++, Cu++, Zn++) en el microscopio electrónico de barrido ambiental equipado con dispersor de rayos X. Se observó que la morfología presentaba mejor constitución y compactación de los cuernos tubulares e intratubulares en el estrato medio, así como aumento sustancial de zinc (32.9%) y de azufre (68.4%), lo cual sugiere incremento de queratina y mejor estructuración del casco.