Nanostructural investigation of frontalis sling biomaterial surfaces

This study examined the nanostructural surface of three frontalis sling biomaterials: autogenous fascia lata, preserved fascia lata and silicone rod. The morphological characteristics of the sling biomaterial surfaces were examined qualitatively and quantitatively by scanning electron microscopy and atomic force microscopy, respectively. The autogenous fascia lata showed well-arranged nanostructures of parallel fascia collagen fibrils with clear 67 nm axial periodicity, whereas the preserved fascia lata showed tangled nanostructures of damaged collagen fibril bundles. The silicone rod showed a substantial amount of debris with some scratches and the smoothest roughness compared with the other sling biomaterials, followed by preserved fascia lata. Autogenous fascia lata showed the highest surface roughness. The association between the roughness and cell adhesion suggests that the nanostructure of autogenous fascia lata biomaterials is the best for frontalis sling and that of the silicone rod biomaterials is the worst.

Regional variability, processing methods, and biophysical properties of human fascia lata extracellular matrix

This study aims to assess the regional variability, processing methods, mechanical, biochemical, and cellular properties of human fascia lata as a scaffold for soft tissue repair and tissue engineering applications. Ten pairs of fascia lata (donor age 18-55) were used. One fascia patch from each pair was used to assess the geometric and biomechanical variability of fresh fascia. The other from each pair was subjected to 1 of 2 allograft processing methods: antibiotic soak alone or acellularization plus antibiotic soak. Stiffness, modulus, hydroxyproline, chondroitin/dermatan sulfate glycosaminoglycan (CSDS GAG), and DNA content were quantified in fascia from fresh and treated groups. The effect of location was not significant for thickness or stiffness within a 6 x 12 cm2 region of the iliotibial tract of fresh human fascia lata. Processing did not significantly change the stiffness, modulus, or CSDS GAG content of fascia ECM. However, hydroxyproline (collagen) content is significantly reduced in acellularized fascia, probably reflecting a removal of soluble collagen during the treatment (p < 0.02). Processing reduced the DNA content of fresh fascia approximately 10-fold (p < 0.001). The mechanical, chemical and ultrastructural similarities between fascia lata and tendon may make fresh or processed fascia an attractive ECM scaffold for soft tissue, particularly tendon, repair.

pN collagen type III within tendon grafts used for anterior cruciate ligament reconstruction

This study measured the amount of immature collagen type III present in tendon rafts obtained from anterior cruciate ligament (ACL) reconstructions. These values were compared with those obtained from control grafts typically used for reconstruction--Achilles, patellar, and fascia lata--and also to the normal ACL. Analyses were performed using a commercially available radioimmunoassay (RIA). The RIA made use of a rabbit polyclonal antibody specific to the amino terminus of procollagen type III. The specificity of the Ab was confirmed by a western blot. Fibril diameter of each of the above samples was measured by transmission electron microscopy (TEM). We thus were able to determine if there was a relationship between pN collagen III content and fibril diameter. The mean amount of pN collagen type III in the normal tendon control group was 0.8 +/- 0.3 ng/microg total protein (range 0.0-2.5 ng/microg). There was significantly greater pN collagen III (16 +/- 3.7 ng/microg total protein) in the grafts containing an average fibril diameter <55 nm than in the normal tendons or ACL (P < 0.05). Grafts with an average fibril diameter >55 nm had similar levels of pN collagen III (1.0 +/- 0.79 ng/microg) as the controls. There was also significantly less pN-collagen III within the functional grafts (5.3 +/- 1.9 ng/microg) as compared to failed grafts, (21.6 +/- 5.1 ng/microg, P < 0.05). These results indicate that incomplete processing of procollagen III may be responsible for some of the ultrastructural alterations seen in tendon grafts. Since ultrastructural organization is believed to influence mechanical properties of these tissues. pN collagen III levels may be a possible indicator of ligament or tendon weakness.

Detailed evaluation of 2959 allogeneic and xenogeneic dense connective tissue grafts (fascia lata, pericardium, and dura mater) used in the course of 20 years for duraplasty in neurosurgery

Surgical experience with 2959 allogeneic and xenogeneic dense connective tissue grafts (1767 of fascia lata, 909 of pericardium, and 283 of dura mater), used in 2665 neurosurgical operations performed in the course of 20 years (1976 to 1995) is reported. Duraplasty using either allogeneic or xenogeneic grafts has had a similar, and favourable clinical outcome. Nevertheless, the pliable deep frozen fascia lata grafts, which could be used in any location, have been reserved for sella turcica plugging, anterior cranial base plasty, aneurysmal wrapping, and surgery of lipomyelomeningocele. Pericardium and dura mater grafts were in the majority of cases used over the brain convexity and posterior cranial fossa. Ovine pericardium proved to be superior to bovine and allogeneic pericardia because of its workability, flexibility, reduced thickness, and better transparency. Postsurgical complications occurred in 7.3%, and they were: 1) cerebrospinal fluid fistulas in 2.8%; 2) meningites in 2.3% (aseptic 1.4%, bacterial 0.8%, and tumoural 0.1% meningites); 3) pseudomeningoceles in 2.2%; 4) wound infections in 0.6%; 5) malresorptive hydrocephalus in 0.5%; and 6) adhesions to nerve tissue in 0.5%. The majority of complications healed without surgery. Forty-eight grafts (1.6%) failed to fulfil the requirements of the surgeon, and 46 of them were re-operated upon. Though another thirty-nine grafts healed successfully, 39 shunts (1.5%) had to be performed for malresorptive hydrocephalus (0.9%), and/or for a big pseudomeningocele (0.6%). So, the pure complication rate in 2665 duraplasties was 3.1%. The complex evaluation of the allogeneic and xenogeneic grafts (fascia, pericardium, and dura mater), used for duraplasty in neurosurgery during the last 20 years proved them, as remarkably good, with a success rates of 96.9%.

Immunolocalization of the costameres in human skeletal muscle fibers: confocal scanning laser microscope investigations

BACKGROUND

The costameres in skeletal muscle fibers were first described by Pardo et al. (1983a) and have been defined as transverse circumferential elements of the cytoskeleton associated to the sarcolemma. Specific immunostaining for vinculin shows that the costameres overlie I bands. However, an exact correlation between the costameres and the Z line is uncertain, although approximately 10 proteins so far have been localized in the costameres. To define the exact localization of costameres in human skeletal muscle fibers, we carried out an immunofluorescence study using confocal scanning laser microscopy on the fascia lata muscle of adult males.

METHODS

Samples were fixed in 3% paraformaldehyde; frozen sections were treated with antivinculin, antitalin, antidesmin, and anti-alpha-actinin, then immunostained with TRITC. For double localization, the TRITC-streptavidin, as a marker for vinculin and FITC-streptavidin a marker for desmin, were used.

RESULTS

The distance between two subsequent transverse lines of actininf indicated that muscle fibers were well stretched. Processing, with different software functions of the images obtained using CLSM, shows that vinculin and talin are only present in the sarcolemmal lattice. Immunostaining for vinculin and double immunostaining for vinculin and desmin demonstrate that costameres superimpose underlying I bands without interruption at the Z line. Immunostaining for talin showed that the protein is located in correspondence with the I band and M line.

CONCLUSIONS

We believe that costameres are "proteic machinery." The findings of the present study suggest that it is possible to determine the width and the period of each proteic component. In addition, we indicate that costameres are present in correspondence with M line.

Structural studies on bovine bioprosthetic tissues and their in vivo calcification: prevention via drug delivery

Cardiovascular calcification, the formation of calcium phosphate deposits in cardiovascular tissue, is a common end-stage phenomenon affecting a wide variety of bioprostheses. To study the process of calcification in tissue prosthetics, glutaraldehyde-treated bovine pericardium, dura mater and fascialata were implanted subcutaneously in rats and retrieved 21 days later and thereby morphological findings were correlated with biochemically determined levels of calcium. Transmission electron microscopy showed that calcification primarily involved the surface of collagen fibrils and the interfibrillar spaces. The deposition of calcium was higher with dura and fascia prostheses compared to pericardium. However, the release of Fe3+ ions from chitosan matrix had substantially inhibited the deposits of calcium in all implanted tissues. It seems that the structural and anatomical features of the tissue is one of the important factors for tissue-associated calcification. It is also confirmed that glutaraldehyde-preserved pericardium is the most suitable material for the development of cardiac prosthesis, with an appropriate drug combination therapy for prevention of pathological calcification.

[Scanning electron microscopy study of autologous vein and fascia lata before and one year after implantation into the arterial blood stream]

The present communication deals with scanning electronmicroscopical changes of autologous vein and autologous fascia lata, which were used as arterial implants. We examined material, which could be removed during reoperation for vascular occlusion. After one year, the surface exposed to the blood stream shows a homogenous layer of fibrin. Whilst the elastic fibers of fascia lata-transplants have nearly completely disappeared, we can still find them in the vein. This might be the essential reason for the longer survival of venous implants into the arterial blood stream.

[Scanning electron microscopy study of autologous fascia lata and bovine xenograft as arterial prosthesis. An experimental study]

The present communication deals with the decomposition of thrombi and the formation of an endothelium in two different vascular prothesis. Devitalized bovine arteries which were enzymatically reduced to a collagen reticulum, and tubes made of autologous fascia lata were implanted into the arterial bloodstream of dogs. The implants were left in place for a time ranging between 30 min and four months. They were examined by scanning electronmicroscope with the cortical point method. This enabled us to reach the following conclusions: unprepared autologous fascia lata implanted into the arterial bloodstream has much more thrombogenous qualities than solcograft. The decomposition of thrombi and the formation of an endothelium is much faster accomplished in fascia lata than in the devitalized bovine artery. It is not possible to distinguish solcograft and fascia lata by the formation of endothelium only.