Generally, mammalian cells and living tissues can be cryopreserved in a frozen state at very low temperatures over a long storage term. The survival rate of cell suspensions is often acceptable however, living tissues suffer a variety of injuries. In this paper, it was demonstrated that the addition of polyphenols extracted from green tea to conventional cell culture medium and tissue compatible liquid, can control cell proliferation and also preserve tissues for several months at ordinary room temperature, including such tissues as blood vessels, cartilage, islet cells and corneas. This protocol allows a non-frozen living tissue bank to be established using the preservation fluid described.
Animals ; Flavonoids/*pharmacology ; Humans ; Organ Preservation Solutions/*pharmacology ; Phenols/*pharmacology ; Tea/*chemistry ; *Tissue Banks ; *Tissue Preservation ; *Tissue Transplantation ; Transplantation, Homologous

In this brief review, some key issues related to vitreous cryopreservation of living tissues (natural or engineered), including cells, embryos, tissues, organs, and engineered tissues, are outlined. The principle of vitreous cryopreservation for the biological activity and functionality is demonstrated. The procedures of cooling/ rewarming, composition and function of optimal cryoprotectants, and their effects on bioproducts are described. Vitrification could, therefore, prove to be a useful and effective method of bioproduct cryopreservation for a long period of time, particularly for organized tissues and organs. However, the toxicity of the cryoprotective agents and the devitrification occurring during the rewarming process need additional investigations. Several key areas of research on vitrification are also addressed.
Cryopreservation ; methods ; Cryoprotective Agents ; pharmacology ; Dimethyl Sulfoxide ; pharmacology ; Humans ; Organ Preservation ; methods ; Tissue Preservation ; methods

The gross tissue specimens are a valuable aid to the teaching of pathology and anatomy. However, traditional methods for storage and handling of them are discouragingly difficult and, recently, minimal surgical resections as well as preoperative interventions make it more difficult to have instructive gross specimens. Plastination is a process of tissue preservation by impregnation with silicone polymers or epoxy resins. The process in our study involves dehydration by cryosubstitution in aceton, defatting, forced impregnation of silicon polymer in a vacuum, curing and finishing. We submitted 40 surgically resected specimens to plastination. The resulting specimens are odorless, relatively dry, durable, life-like, non-hazardous, maintenance-free, and do not deteriorate with time. Plastinated specimens are a useful adjunct to the teaching of pathology, particularly suited for use in small groups, and appropriate method of tissue preservation. They are much preferred to wet preparation and conventional pots by both students and teachers owing to their accessibility, superior illustrative powers, and comparative ease of interpretation.
Dehydration ; Epoxy Resins ; Humans ; Pathology* ; Polymers ; Silicones ; Tissue Preservation ; Vacuum

Cryopreservation is essential for the long-term storage and banking of cartilage grafts. This paper reviews the developments on the cryopreservation of cartilage and transplantation of cryopreserved cartilage grafts during the past 10 years. It is stated that the current technologies for cryopreservation of cartilage grafts are not mature. Further systematic studies are necessary.
Animals ; Cartilage ; transplantation ; Cryopreservation ; Humans ; Tissue Preservation ; methods

OBJECTIVETo investigate the different parameters of the lyophilization procedures that affect the recovery of the rehydrated red blood cells (RBCs).

METHODSHuman RBCs loaded in tubes were cooled with 4 different modes and subjected to water bath at 25 degrees celsius;. The morphological changes of the RBCs were observed to assess the degree of vitrification, and the specimens were placed in the freeze-dryer with the temperature set up at 40, -50, -60, -70 and -80 degrees celsius;. The rates of temperature rise of the main and secondary drying in the lyophilization procedures were compared, and the water residue in the specimens was determined.

RESULTSThe protectant did not show ice crystal in the course of freezing and thawing. No significant difference was found in the recovery rate of the rehydrated RBCs freeze-dried at the minimum temperature of -70 degrees celsius; and -80 degrees celsius; (P > 0.05). The E procedure resulted in the maximum recovery of the RBCs (83.14% ± 9.55%) and Hb (85.33% ± 11.42%), showing significant differences from the other groups(P < 0.01 or 0.05). The recovery of the RBCs showed a positive correlation to the water residue in the samples.

CONCLUSIONFast cooling in liquid nitrogen and shelf precooling at -70 degrees celsius; with a moderate rate of temperature rise in lyophylization and a start dry temperature close to the shelf equilibrium temperature produce optimal freeze-drying result of human RBCs.

Erythrocytes ; cytology ; Freeze Drying ; Humans ; Tissue Preservation ; methods

In this brief review, some key issues related to cryopreservation of seeding cells, scaffolds, and engineered tissues are outlined. The importance of cryopreservation technology to the research and development of tissue engineered products is demonstrated. The biological or biochemical reaction rate must be reduced or completely shut off in order to preserve the tissue engineered products for a long period of time. Cryopreservation may be one of the possible approaches to the fulfillment of this requirement. Seeding cells are stored at low temperature. Tissue engineered scaffold products are usually lyophilized. Engineered tissues are preserved by vitreous cryopreservation technology.
Cell Count ; Cell Survival ; Cryopreservation ; methods ; Humans ; Tissue Engineering ; Tissue Preservation ; Tissue Survival

OBJECTIVETo investigate the effective method of preserving composite facial allograft so as to attenuate ischemic injury.

METHODSThe composite facial allografts were harvested from dog, perfused and preserved with 4 degrees C physiological sodium chloride and UW solution respectively. Immediately after the removal of the flap, after 12, 24, 48 h of preservation, MTT assay was used to determine the viability of several kinds of tissue, including skin, mucosa, muscle, bleed vessel, nerve and gland. The results of the two groups were compared in term of viability percentage. The pathology of several tissues were observed after 24 and 48 h of storage.

RESULTSThe viability percentage of every tissue conserved in UW solution for 48 hours was more than 75%. There was significant difference between physiological sodium chloride group and UW group (P < 0.05). Some changes, including Porous arrangement of fibers in connective tissue of skin and mucosa, hyalinization of tissue around the hair follicle and edema of cell in hair follicle, enlargement of space between muscle bundles and unclearness of boundary of acinus could be seen in physiological sodium chloride group while no significant change in UW group.

CONCLUSIONSUW solution could be considered as preservation solution for composite facial allograft.

Adenosine ; Allopurinol ; Animals ; Dogs ; Face ; Female ; Glutathione ; Insulin ; Male ; Organ Preservation Solutions ; Raffinose ; Tissue Preservation ; methods ; Transplantation, Homologous

Major peripheral arterial graft infection is a potentially devastating complication of vascular surgery, associated with significant mortality and high amputation rates. Autologous saphenous veins are considered optimal arterial conduits for lower extremity revascularization in infected fields, but they are often unavailable or unsuitable in these patients. This study describes two patients with major peripheral graft infection, but without available autologous veins, who underwent graft excision and cryopreserved cadaveric arterial allograft reconstruction. Although long-term graft durability is unclear because of gradual deterioration and degeneration, these findings suggest that cadaveric allografts may be good options for patients with major peripheral graft infection.
Allografts* ; Amputation ; Blood Vessel Prosthesis ; Cadaver* ; Humans ; Lower Extremity ; Mortality ; Saphenous Vein ; Tissue Preservation ; Transplants* ; Veins

The structural failure of the glutaraldehyde-treated xenograft valves has been the primary concern about the limited durability as predicted from the beginning of clinical use, and long-term follow-up has shown a significant incidence of primary tissue failure(PTF) from both biological and mechanical reasons. Twenty-seven patients with the low-profile Ionescu-Shiley valves explanted from mitral position for PTF(Group III) were studied on the patient characteristics and valve pathology, and the results were compared with the matched observations of the Hancock(Group I) and of the standard-profile Ionescu-Shiley valves(Group II). Patients were aged 16 to 56 years(mean, 38.0+/-11.0 years), and the size of the failed mitral bioprosthesis was 30.8+/-1.3 mm. The hemodynamic consequences were stenosis in 29.6%, insufficiency in 44.4%, mixed steno-insufficiency in 14.8%, together with normal function for the rest of patients of prophylactic re-replacement. Pathology revealed calcification with or without tissue damage in 63.0% and tissue damage with or without calcification in 58.1%, in contrast with the observations of predominant tissue damage(76.8%) over calcification in Group I and of calcification(76.1%) over tissue damage in group II. Although dystrophic calcification has long and repeatedly dealt with patient's young age as a determinant of valve durability, such a characteristic evidence was not reached even in patients with calcified valves. Moreover, the prolonged explantation periods from the studied on the previous report suggested strongly yet possibly evolving destructive processes among the valves in the remaining patients, and awaits further follow-up. In conclusion, PTF of the xenograft valves seems to result from more complicated biologic and metabolic reasons as well as more complex mecharical factors than the reported, and newer generation prostheses, with tissue preservation with glutaraldehyde, do not likely to provide decisive improvement in the occurrence of structural failurebioprostheses is generally limited to the highly aged.
Bioprosthesis ; Constriction, Pathologic ; Follow-Up Studies ; Glutaral ; Hemodynamics ; Heterografts ; Humans ; Incidence ; Pathology ; Prostheses and Implants ; Tissue Preservation

BACKGROUND: Current vascular prostheses are considered still inadequate for reconstruction of small-diameter vessels. To evaluate the potential use of xenograft vessels as small diameter arterial grafts, we implanted porcine vessels in goats. The grafts were treated with two different processes, freezing and acellularization, before implantation, and gross inspection as well as microscopic examination followed after a predetermined period. MATERIAL AND METHOD: Bilateral porcine carotid arteries were harvested and immediately stored at -70 degrees C within tissue preservation solution. One of them was designated as frozen xenograft vessel. The other one was put on acellularization process using NaCl-SDS solution and stored frozen until further use. Grafts were implanted in the place of carotid arteries of the same goat. The grafts have remained implanted for 1, 3, and 6 months in three animals, respectively. Periodic ultrasonographic examinations were performed during the observation period. After explantation, the grafts were analyzed grossly and histologically under light microscope. RESULT: All animals survived the experimental procedure without problems. Ultrasonographic examinations showed excellent patency of all the grafts during the observation period. Gross examination revealed nonthrombotic, patent lumens with smooth surfaces. Microscopic examinations of the explanted grafts showed cellular reconstruction at the 6-month stage in both grafts. Although more inflammatory responses were observed in the early phase of frozen xenografts, there was no evidence of significant rejection. CONCLUSION: These findings suggest that porcine xenograft vessels, regardless of pre-implantation processes of acelluarization or freezing, can be acceptably implanted in goats, although short duration of observation in a small number of animals may limit this study.
Animals ; Bioprosthesis ; Blood Vessel Prosthesis ; Carotid Arteries ; Freezing ; Goats* ; Heterografts ; Tissue Preservation ; Transplantation, Heterologous* ; Transplants*