[Experimental study on homograft of the preserved nerve in cialit].
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Human rib cartilage was irradiated with microwaves according to six different methods and transplanted into rabbits. Untreated rib cartilage preserved in Cialit served as a control. After 12 and 40 wk of implantation, the microscopic appearance of these xenogeneic cartilage transplants was given a score in comparison with the transplants preserved in Cialit. The microwave treatment of the cartilage appeared to improve the results. The Cialit-preserved transplants showed progressive resorption by macrophages with central necrosis and fragmentation, which was not present in the microwave-treated grafts. Microwaves seem to stabilize the cartilage matrix and enhance the diffusion of fixatives. Irradiation in ethanol as an immersion fluid appeared to be the best method. The results of transplantation can benefit from the use of microwaves in the preservation of the cartilage. It is argued that, in addition, microwave irradiation might be used for inactivation of human immunodeficiency virus in human cartilage used for transplantation.
Experimental incus transplants were performed in cats. The gross findings and histologic data were recorded and correlated to the use of four preservation methods for homografts (alcohol, Cialit, formalin, and freezing). The formalin preserved incudes produced the least middle ear reaction and ossicular fixation. These incudes also exhibited a uniform perivascular bone remodeling throughout the homograft while the bones preserved in Cialit and alcohol were replaced much faster and ossicular chain fixation occurred. The incus bones preserved by freezing were better tolerated than the Cialit and alcohol ones but not as well as the formalin ones.
HIV-infections can be transferred by blood and blood products, semen or organ transplants. For this reason, the WHO recommended a screening of all donors of blood, semen, tissues and organs. Those who belong to high-risk groups should be excluded from donations. If this recommendation should be also applied to cialit preserved auditory aussicles, this would probably mean the end of allogeneic transplantations of middle-ear surgery which are being performed daily. Therefore, we carried out experimental examinations with HIV-infected auditory aussicles in cialit. According to our results, it can be assumed that a virus-destruction takes place via a cialit-treatment. The same applies to solvent-dried fascia as to auditory aussicles which have been preserved in the same way. Consequently, there is no objection to further application of these allogeneic transplants in respect to HIV-infections.
OBJECTIVE: This study examined the effects of old and new inactivation (sterilization) techniques on the radiologic and mechanical properties of ossicle homografts. MATERIALS AND METHODS: Ninety normal incuses and malleuses received either treatment with 1) 5% formaldehyde/cialit, 2) 1N NaOH, 3) 0.9% LpH, or 4) autoclaving at 134'C, or no treatment. All ossicles were assessed radiologically by high-resolution computed tomography. After imaging, all ossicles underwent mechanical testing by destructive axial compression in a mechanical testing machine measuring force and displacement. RESULTS: Ossicles treated with cialit, NaOH, or autoclaving showed a significant decrease of ultimate force and stiffness compared with controls. LpH treatment caused no such changes in these structural properties. Material properties of yield strength, ultimate strength, and elastic modulus were also altered by cialit, NaOH, and autoclaving, but were much more difficult to assess because of uncertainty in parameter estimates. There was a significant increase in radiologic density in autoclaved ossicles, a reduction in cialit- and LpH-treated ossicles, and no change in NaOH-treated ossicles. CONCLUSIONS: All tested inactivation procedures changed the biomechanical and/or radiologic properties of ossicle homografts. However, the new procedures used to inactivate infectious agents produced changes similar to the older treatments with formaldehyde/cialit. Human allografts are able to withstand harsh but safe sterilization procedures. The NaOH treatment seems to be the most suitable method for the future. The biologic (osteogenic) potentials of ossicle homografts treated with these new preservation/inactivation methods are still unknown. Further investigations are necessary to re-evaluate the clinical use of ossicle homografts in middle ear reconstructive surgery.
During chronic otitis media intact immunoglobulins are split by extracellular bacterial proteinases into fragments of different molecular weight, The most malignant extracellular proteinases with the greatest proteolytic activity against intact immunoglobulins are the bacterial proteinases of Pseudomonas aeruginosa. These proteinases cannot be inhibited by the other serum proteinase-inhibitor except for Alpha-2-Macroglobulin of the human blood serum. This inhibitor has a very high molecular weight, so that we cannot find it in a higher concentration in the middle-ear-secretory. We can liberate this inhibitor by injuring the blood vessels during a tympanoplasty. In this way we get an inhibitory effect against these proteinases and combined with an appropriate antibiotic therapy we can cure a chronic otitis MEDIA. In order to demonstrate that there are immunological reactions in the middle ear against homografted ossicles, various transplantation with homologous ossicles have been performed between two inbreeding rat strains. After sensitisation of the host animals against antigens of the donor animals with skin grafts a reliable histologic infiltration with plasma cells and lymphocytes and the rejection of the graft could be insured. After a simple homologous transplantation without sensitisation, these rejection reactions occurr only rarely and in a diminished form. Cialit storage of middle ear ossicles decreases the solubility of the contained proteins and this in turn diminishes the antigenicity, the amount the antigens, or it retards their liberation. It is for these reasons that Cialit-stored ossicles are more slowly transformed, and there are less inflammatory reactions and adhesions than with untreated ones. The osteogenetic capability of the ossicles is not affected by the Cialit storage.
The ultrastructure of preserved ossicles at different shelf lives was compared. Homograft ossicles were harvested and preserved in 70% alcohol, 1:5000 Cialit (sodium-2-ethyl-mercuri-mercapto-benzoxazole-5-carboxylate), and buffered 4% formaldehyde at pH 7. The ultrastructure of each ossicle was studied by both scanning and transmission electron microscopy and was compared to that of fresh controls placed in 0.9 N saline solution. The results indicated clearly the superiority of 70% alcohol as a long-term preservative and 1:5000 Cialit as a short-term preservative.
Nasal implants of autologous costal cartilage have an undesirable tendency to distortion. This tendency may be reduced by the process of devitalization, which occurs in the preparation of homologous costal cartilage for storage in a tissue bank. An in vitro study has been undertaken, utilizing five common methods of cartilage preparation (cialit, ethyl alcohol, formalin, glutaraldehyde and irradiation) to determine whether there is any significant variation in the degree of distortion which occurred and any variation in cartilage consistency. We conclude that all of the methods evaluated would produce banked homologous costal cartilage with an equally low incidence of distortion but implants are less readily carved from cartilage stored in cialit.
Since chemically preserved allogenic transplants have an established place in reconstructive procedures, the possibility of transferring the human immunodeficiency virus (HIV) with these transplants has been intensively discussed. In this study the authors obtained brain and spleen samples from six HIV-infected cadavers and preserved them with Merthiolate, Cialit, and formaldehyde. After preservation, the tissues were examined for proviral HIV-1 DNA (gag, pol, env) using the polymerase chain reaction. Proviral sequences were clearly demonstrated after the preservation procedure. The results of this study indicate that HIV remains in tissues that have been treated with Merthiolate, formaldehyde, or Cialit. Further investigations are necessary to determine if the virus is in an inactivated or activated form. It can be concluded that, because of the possible transmission of HIV by chemically preserved homografts, serologic screening of donors should be mandatory.
Autogenetic and allogenetic incuses as well as xenogenetic malleus were implanted into the middle-ear of rabbits after different procedures of conservation. The process of healing was studied by histological examination. The different conservation methods are leading to different antigenic qualities of the donor material. A different reorganization along the wurse of the donor vessels is resulting. Accordingly a different extent of osteoneogenesis of the intercellular substance is induced. The vascular tissue showed a revascularization in the case of autogenetic transplantation and in the case of implantation after cialit conservation of 1:5000. Whereas deep-freezing led to swelling, cialit conservation 1:500 to temporary fibrosis of the sides of vessels. Hyalinosis of the vessels was observed after lyophilization and gamma-sterilization of the xenogenetic malleus. The different effects on the healing process are discussed.
UNLABELLED: The report deals with the postoperative results of homologous cialit-preserved tendons and ligaments in 237 patients with 281 homologous cialit-preserved transplants. This material proved to be equally effective to the autologous and even superior to it when grafting flexor tendons of the finger. COMPLICATIONS: 4.7% disturbed woundhealing, 5.2% infections, 5.5% mechanical insufficiency.
In seven three-month old piglets, tracheal defects were created experimentally and Cialit-fixed human tracheal transplants were grafted at the site of the defect. The implants did well in five of the animals, and no signs of respiratory insufficiency (such as stridor, dyspnea or cyanosis) were found. 230-273 days after the transplantation, the animals were sacrificed and the tracheas removed. The transplants were then examined macroscopically and by light, scanning and transmission electron microscopy. Two questions arose: 1) What was the fate of the epithelium of the tracheal graft? It was then found that the host tracheal epithelium surrounding the graft resurfaces the graft. However, a series of morphological changes occur and are described in detail. 2) What happens to the grafted tracheal cartilage? It was found that the cartilage was replaced by thick connective tissue and scar. From the results of these studies, two conclusions could be drawn. 1) The repair of tracheal defects by means of Cialit-fixed human tracheal grafts is limited in those cases in which the newly formed connective tissue is not able to stabilize the tracheal tube. 2) The size of the heterologous tracheal transplant is limited to 6-7 cm2 in animal experiments.
In a multifactorial experiment, dermal sheep collagen was treated in diluted glutaraldehyde solutions, 70% ethyl alcohol, Cialit 1:5000, and distilled water for 1, 3 and 5 min, respectively, in combination with microwave irradiation at different temperature settings. The shrinkage temperature indicating the degree of cross-linking achieved was then determined. Treatment in 0.65% glutaraldehyde with microwave irradiation setting for 60 degrees C resulted in the maximum shrinkage temperature within 1 min, whilst at the lower setting of 50 degrees C, the maximum shrinkage temperature for both glutaraldehyde solutions is only reached after 5 min. Neither microwave irradiation by itself, Cialit or ethyl alcohol induce cross-linking of collagen fibres. These findings are relevant for implant studies.
It is generally agreed that middle ear reconstructive surgery performed with tympano-ossicular homografts produces superior functional results compared with prosthetic material, especially with respect to extrusion rate. The use of homografts, though, has been seriously hampered recently by the fear of transmission of human immunodeficiency virus (HIV) infection. In HIV-infected patients, the virus is primarily found in the cells of the lymphoid and monocytic lineage. The nature of the tissues in the eardrum and ossicles, mostly fibrous tissue and compact bone without marrow, suggests that little virus load should be found in homografts. Indeed, culturing minced homograft tissue from two HIV-infected donors with acquired immune deficiency syndrome (AIDS) in a sensitive culture system with PHA-stimulated lymphoblasts produced no virus. Before use, homografts undergo a fixation procedure in 5% formaldehyde and then are kept in a solution containing Cialit as a preservative. The authors therefore examined the capacity of formaldehyde and Cialit to reduce the infectivity of HIV in models of infected tissue as measured in vitro. The reduction of in vitro infectivity due to these treatments was at least 10(5)-fold and 10(2)-fold, respectively. Coupled with the low virus burden in tympano-ossicular tissue, our data suggests that the fixation procedure affords such a reduction in infectivity that the risk of HIV transmission, even from an HIV-infected donor, is vanishingly low.
A new NaOH-autoclaving inactivation/preservation procedure (IPP) for ossicle homografts, complying with the actual infectious disease guidelines, has been developed and used in our institution for 5 years. This study compares the clinical and audiological results of middle ear reconstruction using the new NaOH-autoclaving inactivated ossicle homografts (22 patients) and the previously used cialit-formaldehyde inactivation procedure (28 patients). During the follow-up period, no homograft extrusion, resorption or disease transmission was observed either for the NaOH-autoclaving or for the cialit-formaldehyde protocol. A postoperative air-bone gap of less than 20 dB in 44% and a postoperative hearing improvement of 10-50 dB in 70% of patients complies with the published success rates of homograft ossiculoplasty in the literature. The analysis and comparison of both tested IPP-patient groups showed no statistically significant differences in the clinical and the audiological results. The NaOH-autoclaving inactivation/preservation protocol should increase ossicle homograft safety even with respect to prion exposure. The good anatomic and audiological long-term results of the new IPP protocol confirm homograft ossicles as a valid and inexpensive approach for middle ear reconstruction.
This report deals with some biological aspects of transplantation and preservation of tympanic membrane and ossicular grafts. The structure and behaviour of tympanic membrane grafts depends largely on the reaction of the preservatives with the tissue proteins. Due to these properties no observable change in the microscopical structure of the membranes and ossicles was found up to 3 years after alcohol and formaldehyde preservation. Preservation in cialit showed gradual disappearance of nuclei and an increasing disintegration of the fibrous structures. Irrespective of the mode of preservation, the fibrous tissue appeared to persist virtually unaffected for long periods. The monocellular reaction found around the grafts preserved in formaldehyde after heterolopie transplantation suggests that tissue antigens are not completely destroyed. A reaction to transplantation in the middle ear is only found around fresh heterologous grafts and around the fresh homologous grafts after previous sensitisation. As observed in rats, ossicles preserved in alcohol or cialit, obtained from revision operations in humans showed partial remodelling. Moreover in some cases these ossicular and especially the cartilaginous grafts showed areas of frank erosion.
The fate of dentine grafts of autogenous, allogeneic and xenogeneic origin has been studied in rats both in muscle and in the middle ear. The dentine has been implanted fresh, autoclaved, Cialit-preserved and demineralised. Xenogeneic material tends to extrude from the ear and not to form a functional union with the structures it contacts. Fresh or Cialit-preserved, autogenous or allogeneic material, eventually stimulate new bone formation and usually become incorporated into the host ossicular chain; however, continuing resorptive activity is present. Autoclaved material does not result in new bone formation; demineralised allogeneic material stimulates very active new bone formation in the ossicular chain. It is concluded that non-demineralised dentine, on account of resorption, is inferior to ossicular grafts as a tympanoplastic material. Demineralised dentine, by virtue of its bone-inductive potential, may be of value in tympanoplasty.