Brief History of the Tissue Bank, Charles University Hospital, Hradec ...

Cell and Tissue Banking 1: 17–25, 2000. © 2000 Kluwer Academic Publishers. Printed in the Netherlands.

Brief history of the tissue bank, Charles University Hospital, Hradec Kr´alov´e, Czech Republic Pavel Mˇeˇriˇcka Head of the Tissue Bank, University Hospital, 500 05 Hradec Kr´alov´e, Czech Republic (Tel.: +(420-49)5513748. Fax: +(420-49)5512346) Key words: tissue bank, allografts, xenografts, haematopoietic progenitor cells, human epidermal keratinocytes, hypothermy, freeze-drying, cryopreservation, Czech Republic Abstract A brief history of the Tissue Bank (TB) of the University Hospital Hradec Kr´alov´e, Czech Republic, established by Dr. R. Klen in 1952 is presented. In Dr. Klen’s original concept the TB was defined as a department specialised in the harvesting, processing, preservation, storage and distribution of various kinds of tissue for clinical and experimental practice. The first kinds of tissue collected in cadaveric donors were corneas, bone and skin. Xenogeneic cartilage and bone grafts were prepared at the same time. Later, preparation of soft connective tissues and chorion–amnion was introduced. During the first 15 years of activity a total of 11,443 grafts preserved by hypothermy at +4◦ C or freezing in absence of cryoprotectants (−20◦ C) were prepared. In the 60’s freeze-drying of tissue grafts was introduced and the bank of cryopreserved cell lines was established. In the 80’s cryopreservation of haematopoietic progenitor cells for clinical transplantations was started and the spectrum of tissue grafts was enlarged (xenogeneic pericardium and allogeneic specially treated dura mater for neurosurgical operations, pigskin for burn treatment, demineralised bone for parodontology and implantology). In the 90’s human keratinocyte culture for treatment of burns and chronic skin defects was started. The human milk bank and organ bank co-operating with the Regional Transplantation Centre are component parts of the TB as well. The TB is an institutional member of the European Association of Tissue Banks and annually delivers approximately 1000 grafts that are used in University and county hospitals as well as in surgeons’ private practices. Health insurance companies reimburse all grafts on a non-profit and tax-free basis. Abbreviations: TB – Tissue bank; PBPC – Peripheral blood progenitor cells; CFU-GM – Granulocyte-macrophage colony forming units; IAEA – International Atomic Energy Agency

The Tissue Bank of the University Hospital in Hradec Kr´alov´e was established in October 1952 by Dr. Rudolph Klen, on the basis of his own concept presented on the occasion of the 14th National Congress of the Czechoslovak Society for Orthopaedics, Surgery and Traumatology in Prague in 1951 and published in 1952 (Klen 1952). Dr. Klen, who later received the degree of Doctor of Science and was made Professor of the Charles University, defined the TB as a department specialised in the harvesting, preservation, storage and distribution of various kinds of tissue for clinical and experimental practice. The department started its work in very modest conditions, in one room located in the Department of

Surgery. This room was used for the processing and storage of tissue. The tissue harvests were performed in the Department of Pathology and the Department of Forensic Medicine or directly in the clinical wards. The TB started its work with only 2 staff members, Dr. Klen, who held the position of head of department until 1984 and the technician Mr. Z. Huˇsek, who retired in 1993. The first preservation methods were simple: hypothermy at +4◦ C (moist chamber or special soluˇ 1955). tions) or freezing at −20◦ C (Klen & Skrovina The first kinds of tissue collected and transplanted were corneas, compact and cancellous bone, cartilage, skin and chorion–amnion. Since 1954 xenogeneic bone (calf ) has been collected and preserved for

18 ˇ transplantation in man (Klen & Skrovina 1955, Klen 1966). The activity of the TB aroused the attention of surgeons to problems of tissue transplantation, so that it was already possible to organise the first Czech conference on tissue transplantation in June 1953. The proceedings of the conference, that was organised by the Military Medical Academy in Hradec Kr´alov´e, were published in 1954 (Group of authors 1954). The general problems of transplantation were reviewed by Col. Prof. Vavrda, head of the Department of Orthopaedic Surgery at Military Medical Academy, Hradec Kr´alov´e and the detailed concept of the harvesting and preservation of tissue for transplantation purposes was presented by Dr. R. Klen. The basic problems of clinical tissue transplantations in different surgical disciplines were reviewed by leading Czech and Slovak surgeons: Prof. Burian – plastic surgery, Ltc. Ass. Prof. Sazama – stomatosurgery, Dr. Hradec-vascular surgery, Prof. Zahradn´ıcˇ ek – orthopaedic surgery, Dr. Halmoˇs – face surgery. A proposal of the special law regulating the harvest of cadaveric tissue on the basis of the presumed consent of the donor as well as other activities of the TB, that was elaborated by Dr. Dost´al from the

P. Mˇerˇiˇcka Regional Court in Hradec Kr´alov´e, was also published (Dost´al 1954). The second conference on tissue transplantation was held in June 1954 (Figure 1). In 1957, the monograph ‘Biological Basis of Tissue Preservation’ by Dr. R. Klen was published (Klen 1957). It was later translated into Russian and a completely revised version was published in English in 1982 (Klen 1982). The total number of different kinds of grafts prepared in the first 15 years of activity is shown in Table 1. The 10,000th graft was prepared in 1964 (Figure 2). In the late fifties and early sixties the main preservation methods continued to be simple hypothermy in cornea, skin (Klen 1965, Klen & Heger 1969) and massive osteochondral grafts and freezing in absence of cryoprotectants in bone, cartilage and soft connective tissue. An original decontamination method based on the immersion of tissue in precooled ethanol, the so-called ‘cold shock’, was used (Klen 1959). The first experiments with freeze-drying were started in 1963 and the first freeze-drying apparatus was obtained one year later (Figure 3a). The conditions for the further development of the TB were created after 1967, when the TB moved to the new building of the Institute of Pathology. The separate

Figure 1. The view of the lecture hall of the Surgical Department of the University Hospital Hradec Kr´alov´e during the 2nd Conference on Problems of Tissue Transplantation, 19–20 June, 1954 (In the years 1951–1958 the Medical School at Hradec Kr´alov´e including the clinical departments was separated from the Charles University in Prague and turned to the Military Medical Academy.)

Brief history of tissue bank

19 Table 1. Number of grafts prepared in the years 1952–1966 Tissue

1952–56

Allogeneic grafts Cornea Compact bone Cartilage Fascia lata Dura mater Skin Chorion-amnion

1118 116 96 10 0 48 16

380 88 230 273 0 243 22

956 405 477 553 18 621 0

2454 609 803 836 18 912 38

Total allogeneic grafts

1404

1236

3030

5670

Xenogeneic grafts Compact bone Cancellous bone Bone grafts for Cloward operation

510 342 0

1285 1077 0

1535 990 34

3330 2409 34

852

2362

2559

5773

2256

3598

5589

11443

Total xenogeneic grafts Total of all grafts

1957–61

1962–66

Total

Figure 2. Dr. R. Klen (left) and Mr. Z. Huˇsek showing the 10,000th tissue graft (Courtesy Dr. Z. Huˇsek).

operating room for aseptic tissue harvest (Figure 4) and the freeze-drying laboratory (Figure 3b) were parts of the new TB. The freeze-drying technology was introduced by PhMr. Jeˇzek and PhMr. and RNDr. Heger (Heger 1971). Their work is being continued by Eng. L. V´avra.

Introduction of freeze-drying, supplemented later with radiation sterilisation by a dose of 25 kGy made it possible to supply many surgical departments in the former Czechoslovakia with tissue grafts. The grafts were also sent abroad, some of them to countries in the Middle East and to many hospitals in Eastern and Western

20

P. Mˇerˇiˇcka

(a)

(b)

Figure 3. (a) The first freeze-dried grafts were prepared in the apparatus KS 6 (Frigera Kol´ın, Czechoslovakia). The Tissue Bank staff members, Dr. R. Klen (right), RNDr.J. Heger (left) and Mr. Z. Huˇsek, are showing the freeze-drying technology to Mr. J. N¨ather, the technician of the Berlin Tissue Bank (1965) (Courtesy Dr. Z. Huˇsek). (b) The most of freeze-dried tissue. grafts were prepared in the equipment LZ 9 (Frigera Kol´ın, Czechoslovakia). The view to the freeze-drying laboratory in the 80’s, Eng. L. V´avra at the control panel. Frozen grafts were stored at −50◦ C in the freezers ZZ 150/50 (in the front) of the same producer.

Brief history of tissue bank

21

Figure 4. Dr. Mˇeˇriˇcka assisted by Dr. Strakov´a during harvest of allogeneic skin graft at the operating room of the Tissue bank (1985).

Europe. Many grafts were also used by Czech surgeons working in developing countries at that time, especially in Africa (Klen 1976). These activities were supported by the World Health Organisation and the International Atomic Energy Agency. Besides frozen and freezedried compact and cancellous xenogeneic and allogeneic bone (Klen 1961, 1966, Mareˇcek et al. 1979, Mˇeˇriˇcka & Klen 1979, Mˇeˇriˇcka 1982), the materials used for reconstruction of dura mater, especially fascia lata (Klen et al. 1977) and biological skin covers, especially amnion and chorion amnion (Klen et al. 1968, Dlabalov´a et al. 1972, Klen & Skalsk´a 1976) were the most frequently used grafts. Fascia lata grafts were used also in abdominal surgery and ophthalmology (Svˇer´ak et al. 1979). The frozen and freeze-dried grafts were wrapped in National Blood Transfusion Service jars of different sizes. The soft tissue was rolled on polyamide texture carriers (Figure 5). In the late sixties the number of grafts prepared culminated and reached 3000 per year. In these years also cryopreservation of tissue culture cells with subsequent storage in liquid nitrogen was started and the collection of defined cell lines was established (Heger et al. 1971). Co-operation with the kidney transplantation team formed at the Department of Urology by Prof. Navr´atil, who performed the first kidney transplantation in Czechoslovakia in 1959,

began in the early seventies. At the same time the plan to establish a bone marrow bank was designed (Klen 1976). The human milk bank (Klen 1981), which has been a part of the TB since 1958, has developed rapidly since 1974 (Table 2). In 1981 first world conference on human milk banking was organised and the proceedings were published in co-operation with the International Institute of Refrigeration (IIR 1981). In the eighties some changes in the technology of graft preparation occurred and the spectrum of prepared grafts was again enlarged in co-operation with surgeons from different disciplines: Dr. Paˇrizek – neurosurgery, Dr. Klein – burn surgery, Dr. Dˇrizhal – stomatosurgery, Dr. Rozs´ıval – ophthalmology. Glutaraldehyde-stabilised calf pericardium was introduced as a dura mater replacement in 1983 (Mˇeˇriˇcka et al. 1986, Paˇr´ızek et al. 1989) and the specially pretreated freeze-dried human dura mater in 1986 (Paˇr´ızek & Mˇeˇriˇcka 1990, Mˇeˇriˇcka 1991, Strakov´a & Mˇeˇriˇcka 1991). Porcine dermoepidermal grafts prepared according to the modified method of the Prague Burn Centre (Moserov´a 1974) were introduced in 1985 to supply the demand of the newly opened Department of Plastic Surgery and Burn Treatment (Mˇeˇriˇcka et al. 1987, 1995, Klein et al. 1995). Allogeneic sclera enlarged the spectrum of grafts used

22

P. Mˇerˇiˇcka

Figure 5. Freeze-dried radiation sterilised chorion–amniotic graft prepared for delivery to the Burn Unit in Pardubice (1983). Radiation sterilisation was performed by the Radiation Sterilisation Centre in Veversk´a B´ıt´ysˇka.

Table 2. Amount of human milk processed in the year 1958–1981 Year

Amount of human milk (litres)

Year

Amount of human milk (litres)

1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969

80 190 130 160 80 400 250 445 330 60 197 50

1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981

155 107 198 165 324 102 702 1339 2599 4247 5108 5497

for scleroplastics performed in severe myopia (Mˇeˇriˇcka et al. 1988, Rozs´ıval & Mˇeˇriˇcka 1988, Rozs´ıval et al. 1997). Allogeneic demineralised bone grafts for application in parodontology were introduced in 1986. The use of xenogeneic bone was gradually abandoned. In soft connective tissue grafts, wrapping in jars was replaced by freeze-drying in flat format and use of

plastic bags (Mˇeˇriˇcka et al. 1987). As an alternative to the radiation sterilisation method, ethylene-oxide sterilisation was also used. Frozen grafts were stored at −70◦ C or −80◦ C. For pigskin grafts and allogeneic dermoepidermal grafts, cryopreservation with glycerol or dimethylsulphoxide was introduced with subsequent storage at −80◦ C or liquid nitrogen (Mˇeˇriˇcka et al. 1987). In 1988 the cryopreservation of peripheral blood progenitor cells (PBPC) was introduced to clinical practice using stainless-steel containers of our own construction for programmed freezing and storage of PBPC concentrates and glycerol as a cryoprotectant (Mˇeˇriˇcka et al. 1991). The first results of the clinical application of cryopreserved PBPC concentrates in haematological malignancies were published by Ass. Prof. M. Bl´aha, Ph.D. from the 2nd Department of Internal Medicine (Bl´aha et al. 1990). Since 1991 metal containers have been replaced by plastic bags and dimethylsulphoxide instead of glycerol has been used as a cryoprotectant (Mˇeˇriˇcka 1997). In 1993 the programme of culture human epidermal keratinocytes was introduced by Dr. Strakov´a (Strakov´a et al. 1995) and the first application in burn surgery was performed (Klein et al. 1997, Mˇeˇriˇcka et al. 1998). Preservation of cornea in Optisol, used since 1994, made it possible

Brief history of tissue bank

23

Figure 6. Leading world cryobiologists Prof. P. Mazur (Oak Ridge National Laboratory, USA) (left) and Prof. L. McGann (University of Alberta, Edmonton, Canada) during discussion at the conference ‘Theoretical Basis of Cryopreservation’, held in Hradec Kr´alov´e in 1992.

to extend the shelf life of corneas to 3 weeks and contributed to increasing the number of keratoplasties performed in the Ophthalmology Department (approximately 100 per year). In 1996 the first cryopreserved venous grafts were successfully transplanted. Until 1992, all tissue grafts were delivered to the cooperating clinical departments free of charge and all costs were paid by the University Hospital, which was funded directly from the state budget. Since the beginning of 1993, the health service in the Czech Republic – including the reimbursement for the preparation of tissue grafts – has been funded by health insurance companies (Mˇeˇriˇcka 1996). Currently the Tissue Bank consists of the following divisions: 1. Classic TB providing allogeneic and xenogeneic tissue for use in clinical practice. The health insurance companies list all grafts and the costs are reimbursed on a non-profit and tax-free basis. The TB prepares more than 1000 grafts per year. The most commonly used are materials for duraplasty, biological skin covers, corneas for keratoplasties, sclera grafts for scleroplastic operations and demineralised bone in parodontology and dental ˇ unek & Kopeck´a 1998). Most implantology (Sim˚ grafts are wrapped in disposable plastic peel-packs.

A temperature of −80◦ C is exclusively used for storage of deep-frozen and/or cryopreserved grafts. The grafts are sent to surgical departments in the Czech Republic and to some hospitals in the Slovak Republic. The total number of co-operating departments exceeds 30 and includes both university departments, county hospital departments and surgeons’ private practices. 2. Haematopoietic progenitor cell bank that processes cryopreserves and stores stem cells collected from the peripheral blood, separated bone marrow and, since 1998, cord blood as well. The concentrates are used in autologous and, since 1997, in allogeneic transplantations in haematological malignancies and in the supportive care of solid tumours, especially advanced breast cancer. The bank supports the newly opened (1997) Haematology– Oncology Department designed to perform 50–60 haematopoietic progenitor cell transplantations per year. This level was already achieved in 1998. 3. Organ Bank that co-operates with the Regional Kidney Transplantation Centre performing 40–50 transplantations per year. 4. Tissue culture and engineering laboratory that performs CFU-GM cultures as the quality control test for haematopoietic progenitor cell

24 cryopreservation and culture of the autologous and allogeneic epidermal keratinocytes used in the treatment of burns and chronic defects. 5. Human milk bank carrying out the collection, pasteurisation, preservation and quality control of milk distributed to the paediatric departments of the East Bohemian region (V´avra 1981). The milk is preserved by freezing to −20◦ C or by freeze-drying. In 1996 the new milk bank designed according to the latest hygienic requirements was opened. Approximately 2000 l of frozen human milk are delivered annually to co-operating paediatric departments. The TB is an institutional member of the European Association of Tissue Banks and also co-operates with other international organisations such as the European Burns Association and the International Institute of Refrigeration. The head of the department is a member of a recently established Commission for Tissue Transplantation attached to the Institute for Experimental and Clinical Medicine in Prague that is licensed by the Czech Ministry of Health to co-ordinate organ and tissue transplantation programmes. The TB has organised many international conferences and symposia dealing with theoretical and practical aspects of cryobiology and tissue banking and transplantation (Figure 6). Undergraduate and post-graduate courses in tissue banking were established by Prof. Klen (Klen 1976). This tradition is still being followed. The postgraduate training courses are attended by both Czech and foreign specialists; some of these are supported by the IAEA. Obligatory undergraduate practical training in tissue banking for Czech and foreign students was implemented in the 3rd school year of the Medical School of the Charles University in Hradec Kr´alov´e in the course in General Pathology. The TB also offers an optional summer training programme for students of foreign Schools of Pharmacy.

References cited Bl´aha M et al. (1990) Transplantation of haematopoietic stem cells of peripheral blood-first experience (in Czech). Voj zdrav listy LIX: 218–223 Dlabalov´a H et al. (1972) Treatment of leg ulcers with chorion ˇ Dermatol 47: 42 grafts (In Czech). Cs Dost´al F (1954) Proposal of the law on activities of tissue centres. In: Group of Authors. Tissue Transplantation (in Czech), pp 92– 95. St´atn´ı zdravotnick´e nakladatelstv´ı. Praha Group of authors (1954) Tissue Transplantation (in Czech). St´atn´ı zdravotnick´e nakladatelstv´ı, Praha

P. Mˇerˇiˇcka Heger J et al. (1971) Open defension of work of the collection of defined cells attached to the Tissue Bank of the University Hospital Hradec Kr´alov´e (in Czech). Sborn´ık vˇed. prac´ı LF KU v Hradci Kr´alov´e, Suppl. 14: 129–173 Heger J (1973) Freeze-drying of tissue grafts for transplantation (in Czech). Ph. D. Thesis. Charles University School of Pharmacy, Hradec Kr´alov´e Human Milk Banking/Les Banques de lait humain (1981) Proceedings of the Commission C-I Meeting, Hradec Kr´alov´e, Czechoslovakia, International Institute of Refrigeration, Paris Klein L et al. (1995) Clinical experience with skin xenografts in burned patients. In: Maselis M and Gunn SWA (eds) The Management of Burns and Fire Disasters: Perspectives 2000 Proceedings of the Second International Conference on Burns and Fire Disasters, pp 343–345. Palermo Kluwer, Academic Publishers Klein L et al. (1997) Biological skin covers in treatment of two cases of the Lyell’s syndrome. Annals of Transplantation 2: 45–48 ˇ nemocnice 20: Klen R (1952) Tisssue centre (TC) (in Czech). Cs 120–121 ˇ Klen R and Skrovina B (1955) Solution for preservation of bone tissue and cartilage (in Czech). Rozhl Chir XXXIV: 483–486 ˇ Klen R and Skrovina B (1955) Growth zone-new material for bone plasties (in Czech). Rozhl Chir XXXIV: 479–483 Klen R (1966) Long term results with processed heterogeneous bone grafts from the tissue bank in Hradec Kr´alov´e (in Czech). Rozhl Chir XLV: 471–478 Klen R (1957) Biological basis of tissue preservation (in Czech). St´atn´ı zdravotnick´e nakladatelstv´ı, Praha Klen R (1982) Biological principles of tissue banking. Pergamon press, Oxford, New York, Toronto, Sydney, Paris, Frankfurt Klen R et al. (1965) Use of the anterior chamber of the eye for selection and preservation of cornea. Am J Ophthalmol 60: 879–889 Klen R and Heger J (1969) A contribution to degradation of skin and cornea preserved hemibiotically in the temperature near 0◦ C. Acta Chir Plast 11: 47–55 Klen R (1959) Cold shock. Folia Biol 1/V: 82–83 Klen R (1961) Entstehung von Metastasen bei Verschieden nach Entfernung von B¨osartigen Knochenneubildungen verwendeten Knochensp¨anen. Radiobiol Radiother 2/1: 109–115 Klen R et al. (1977) Freeze-dried-homogeneous graft of fascia lata in neurosurgery. J Neurosurg Sci 21: 247–250 Klen R et al. (1968) Experimental study of factors influencing take and survival of human skin homografts. Plast Reconstr Surg 41: 471–476 Klen R and Skalsk´a H (1976) A comparison of dermoepidermal and chorionamniotic grafts in the treatment of burns. Acta Chir Plast 18: 225–232 Klen R (1976) Tissue banking in Czechoslovakia. Transplantation Proceedings VIII, Suppl. 1: 49–51 Klen R (1981) Human milk bank at the Medical Faculty Hospital in Hradec Kr´alov´e (aspects of organisation). In: Human Milk Banking /Les Banques de lait humain. Proceedings of the Commission C-I Meeting, Hradec Kr´alov´e, Czechoslovakia, pp 19–23. International Institute of Refrigeration, Paris Mareˇcek V et al. (1979) Long-term results of treatment using heteregenous grafts at the Department of Orthopaedic Surgery of the University Hospital in Hradec Kr´alov´e (in Czech). Sborn´ık vˇed prac´ı LFKU v Hradci Kr´alov´e, Suppl.: 119–122

Brief history of tissue bank Mˇeˇriˇcka P and Klen R (1979) Short-term clinical results with application of long term stored freeze-dried bone and cartilage grafts (in Czech). Sborn´ık vˇed prac´ı LFKU v Hradci Kr´alov´e, Suppl.: 29–42 Mˇeˇriˇcka P (1982) Thirty Years of The Tissue Bank of the University Hospital Hradec Kr´alov´e (in Czech). L´ekaˇrsk´e zpr´avy (Hradec Kr´alov´e) 27: 195–206 Mˇeˇriˇcka P et al. (1986) Vorbereitung und klinische Anwendung von xenogenen durch Glutaraldehyd fixierten lyophilisierten Pericardium Transplantaten. Probleme der H¨amatologie Transfusion und Transplantation 13: 345–358 Mˇeˇriˇcka P (1991) Preservation and Clinical Application of Soft Tissue Grafts. Charit´e Report 7: 8 Mˇeˇriˇcka P (1991) Specially treated freeze-dried dura mater – perspective material for duraplasties (in Czech). L´ekaˇrsk´e zpr´avy, Hradec Kr´alov´e 36: 49–59 Mˇeˇriˇcka P et al. (1987) Cryopreservation of dermoepidermal grafts for treatment of burns. In Proceedings of the XVIIth International Congress of Refrigeration, Commission C-I, Vienna 24–29.8. 1987, pp 1–8. International Institute of Refrigeration, Paris Mˇeˇriˇcka P et al. (1995) The role of the tissue bank in disaster planing. In Maselis M and Gunn SWA (eds) The Management of Burns and Fire Disasters: Perspectives 2000. Proceedings of the Second International Conference on Burns and Fire Disasters, pp 75–83. Kluwer Academic Publishers, Palermo Mˇeˇriˇcka P et al. (1988) Low Temperature preservation of collageneic tissues for transplantation purposes and their possible use. In Proceedings of the XVIIth International Congress of Refrigeration, Commission C-I, Vienna. In Proceedings of the XVIIth International Congress of Refrigeration, Commission C-I, pp 9–15. International Institute of Refrigeration, Paris Mˇeˇriˇcka P et al. (1991) Containers for freezing and storage of bone marrow stem cells. Sb. vˇed. prac´ı L´ek. Fak. Karlovy Univ., Hradec Kr´alov´e 34: 367–387 Mˇeˇriˇcka P et al. (1997) Validation of the standard operating procedure for cryopreservation of peripheral blood progenitor cells (PBPC). In IIR International Conference, Commission C-I Cryoprotectants in Medical Practice May 12–15 1997, Hradec Kr´alov´e, Long Abstracts, p 19 International Institute of Refrigeration, Paris

25 Mˇeˇriˇcka P et al. (1998) Practical aspects of establishing an allogeneic keratinocyte bank. Roczniki Oparzen, Annals of Burns 105–109 Mˇeˇriˇcka P (1996) Tissue banking in the Czech Republic – current status. In Byk JRCh, Lechat A and von Versen R (eds) 4th International Conference European Association of Tissue Banks, pp 47–50. Monduzzi Editore, Bologna Mˇeˇriˇcka P et al. (1998) Biological skin cover: banking and application. In: Phillips GO, Strong DM, von Versen R and Nather A (eds) Advances in Tissue Banking, vol 2, pp 323–341. World Scientific Singapore, New Jersey, London, Hong Kong Moserov´a J et al. (1974) Bacteriological control of dermoepidermal grafts from porcine hides (in Czech) Rozhl Chir 53: 631–634 Paˇr´ızek J et al. (1989) Xenogeneic pericardium as a dural substitute in reconstruction in suboccipital dura mater in children. J Neurosurg 70: 905–909 Paˇr´ızek J and Mˇeˇriˇcka P (1990) Duraplasty with pre-treated freeze-dried sterilized human dura mater. Sborn´ık vˇed. prac´ı L´ek. Fak. Karlovy Univ. Hradec Kr´alov´e 30: 135–143 Rozs´ıval P and Mˇeˇriˇcka P (1988) Unsere Erfahrungen bei Operationen mit Skleraplastiken nach Pivovarow. Folia Ophthalmol 13: 121–123 Rozs´ıval P et al. (1997) Long-term results of scleral reinforcement in children. In S¨uveges I and Folmann P (eds) SOE 97 1st edition, pp 957–961. Monduzzi edittore, Bologna Strakov´a H and Mˇeˇriˇcka P (1991) Analysis of demand of grafts used for dura mater plasty in the Czech and Slovak Federal Republic (in Czech). L´ek. zpr. LF UK, Hradec Kr´alov´e 36: 135–143 Strakov´a H et al. (1995) Culture of epithelial Sheets from Cryopreserved keratinocyte primocultures. Journal of Experimental and Clinical Cancer Research 14 Suppl.: 99–101 Svˇer´ak J et al. (1979) Fascia lata in the Retina Detachment Surgery. Sborn´ık vˇed prac´ı L´ek. Fak. Karlovy Univ. Suppl.: 123–126 ˇ unek A and Kopeck´a D (1998) Our experience with use of Sim˚ freeze-dried demineralised bone in dental implantology (in Czech). LKS (Chamber of Stomatologists), 8: 8–9 V´avra L (1981) Treatment of Human Milk. In Human Milk Banking – Les Banques de lait humain. Proceedings of the C-1 Commission Meeting, Hradec Kr´alov´e, pp 25–31. International Institute of Refrigeration, Paris