Acta histochem. 90, 87-91 (1991) Oustav Fischer Verlag Jena
Departments of Dermatology, University of KOln, FRO* and Jena, FRO**, Department of Plastic Surgery University of Jena, FRO***
Immunohistochemistry of porcine skint) By UWE WOLLINA*'**, UWE BERGER*** and GUSTAV MAHRLE* With one Figure (Received August 6, 1990) Key words: Porcine skin - Immunohistology - Epidermis - Dermis
Abstract The present paper reports immunohistological findings in porcine skin, which were obtained by use of monoand polyclonal antihuman antibodies and either alkaline phosphatase anti-alkaline phosphatase (APAAP) or peroxidase (POX) technique. Epidermal staining was observed with antibodies to keratins (K 8.12, RKSE 60), filaggrin, and calmodulin (ACAM). Staining of connective tissue and vessels was achieved using antibodies to vimentin (V9(l)), collagen type IV, and fibronectin. In general, these antibodies gave a staining pattern similar to that of normal human skin. The similarities of immunoreactivity to poly- and monoclonal antihuman antibodies in porcine and human skin render porcine skin a reliable model in biomedical research.
1. Introduction Skin models are of increasing interest in various fields of biomedical research, such as dermatology, pharmacology, toxicology, surgery, and radiation biology. While most studies have used laboratory animals, e.g. rats, mice, or guinea pigs, there are striking differences to human skin. It has been reported that porcine skin of both domestic or minipigs offers several advantages, because it resembles human skin in its morphologic, histochemical, and cell kinetic qualities (ARCHAMBEAU and BENNETT 1984; MEYER et al. 1978, 1986; MEYER and NEURAND 1987; MEYER and GORGEN 1986; TSUKISE and MEYER 1983). MEYER et al. (1986) reported immunohistological findings in porcine skin using 3 polyclonal antibodies against human keratins, which indicated a common pathway of keratinocyte differentiation in both porcine and human skin. Since monoclonal antibodies to porcine tissue antigens are still lacking (GROVES and TUCKER 1989), we tested a number of mono- and polyclonal antibodies to human epidermal as well as dermal antigens.
2. Material and methods Tissue samples from the thoracic region of 6 minipigs were obtained from the Centre of Animal Research at the Department of Medicine of the University of Jena. After removal, skin specimens were snap frozen in liquid nitrogen and cut at 5 !AJIl. Acetone fixed sections were used for immunostaining. 1) This study was performed during a research fellowship of Dr. U. WOLLINA at the University of KOln, Department of Dermatology.
88
U. WOLLINA et al.
Table. 1. List of primary antibodies Antibody
Characterization
Specificity
Source
Dilution
CAM 5.2 RKSE60
monoclonal IgG2a
keratins 8/18/19 keratin 10
Becton Dickinson Euro-Diagnostics
keratins 13/16
Bio-Marker
keratin 18 filaggrin, profilaggrin vimentin CD 54 EGF-receptor
Boehringer Paesel
1:2 1 :50 1: 100 1 :50 1: 100 1 :5 1 :50
(POX) (POX) (APAAP) (POX) (APAAP) (APAAP) (POX)
1: 10 1 :50 1:500 1 :2000 1:1 1 :50 1:50 1: 100 1: 100
(POX) (POX) (POX) (APAAP) (POX) (POX) (POX) (POX) (POX)
K 8.12 CK2 Filaggrin
monoclonal IgG 1
V9 (1) ICAM-l 29.11 BF 8 ACAM Collagen IV Fibronectin F-Vill-rAg
}
monoclonal IgG2a polyclonal rabbit monoclonal IgG 1 polyclonal rabbit
calmodulin calmodulin collagen type IV fibronectin factor-Vill-related antigen
Monosan Immunotech Sigma Dr. P. JABLONSKI Dr. I. WENZ Biogenesis Dako Dako
The primary antibodies employed are summarized in Table 1. Secondary antibodies used for peroxidase technique (POX) or alkaline phosphatase anti-alkaline phosphatase technique (APAAP) were purchased from Dako (Hamburg, FRG). Immunostaining procedures were performed according to standard protocols. 3-amino-9-ethyl-carbazole was used to visualize the peroxidase activity in POX and naphthol-bi-phosphate served as substrate in APAAP (see also table 1). In controls, the primary antibody was replaced by buffer solution.
3. Results In Table 2, several mono- and polyc1onal antibodies are listed, which stained both human and pig skin antigens. Table 2. Comparative immunostaining of percine and human skin Antibody
Pig Epidermis
CAM 5.2 RKSE 60 K 8.12 CK2 Filaggrin V9 (1) ICAM-l 29.11 BF 8 ACAM Collagen IV Fibronectin F-Vill-rAG
Human Dermis/Vessels
Epidermis
Dermis/Vessels
+
-/-/-
+
-/-/-
-/-
+ +
+
-/-
-/-/-/-
+1+
+
-/+
+ + +
-/-/-/-
+/+ +/+ -/-
+ + +
-/-
+1+ -1+ -1+ -/-/-
+/+
+1+ -1+
Porcine skin
I a lblld 1c
1
89
Fig. 1. Irnrnunostaining of porcine skin with monoclonal antibodies against intermediate filaments and filaggrin. a Basal epidermal staining with antibody K 8.12. b Suprabasal epidermal staining with antibody RKSE 60. c Subcorneal staining with anti-filaggrin. d lrnrnunostaining of epidermal dendritic (Langerhans ?) cells, deflI)al fibroblasts and vessel walls with antibody V9(l). Methods: APAAP for a-c; POX-AEC for d. X 250.
Antibodies to keratins labelled either basal (K 8.12) or suprabasal keratinocytes (RKSE 60) . As in human epidermis antibodies to glandular type keratins, i.e. CAM 5.2 and CK 2, failed to react with porcine epidermis. Anti-filaggrin marked the subcomeal stratum granulosum (Fig. 1 a to c). The polyclonal ACAM against calmodulin produced a faint cytoplasmic staining of basal cells and sometimes of subcomeal cells. The basal membrane was decorated by antibodies to type IV collagen and fibronectin. Dermal vessels were stained with antibodies to ICAM-l, but neither with those to factor VIII-related antigen nor to EGF-receptor. The vimentin antibody disclosed a cytoplasmic staining of epidermal dendritic cells, dermal fibroblasts, and vessel walls (Fig. 1 d).
Discussion Porcine skin has become a reliable model for biomedical research in recent years. It has gained special attention for radiobiologists (ARCHAMBEAU 1989; ARCHAMBEAU and BENNETT 1984), pharmacologists (CARVER et al . 1989; RIVIERE etal. 1986; WILLIAMS and RIVIERE 1989), and surgeons (DYSON eta!' 1988; HEBDA 1988; HUKKI eta!' 1989; RICCIARDELLI et al. 1989). Thus, there is an increasing interest in evaluating epidermal differentiation
90
U. WOLLINA et al.
and skin immunohistology in domestic pigs and minipigs (MEYER and GORGEN 1986; MEYER etal. 1986). The lack of antibodies to porcine skin antigens makes it necessary to search for antihuman antibodies cross-reacting with porcine tissue (cf. GROVES and TUCKER 1989). GIGI et al. (1982) described a broad-spectrum antibody to human cytokeratins (KG 8.13), which was reactive on tissue sections of mouse, cow, and pig. Another monoclonal antibody CK4 against human keratin 18 labelled pig mammary glands (DEBUS et al. 1982). MEYER et al. (1986) reported immunohistological findings on porcine epidermis using 3 different polyclonal antibodies to human cytokeratins. In the present paper, antibodies to human keratins, such as K 8.12 and RKSE 60, labelled porcine epidermis. This suggests the presence of keratins 16 and 10 (HUSZAR etal. 1986; RAMAEKERS etal.1983) in the basal and the suprabasallayer, respectively. Similar staining patterns were observed in human skin. The monoclonal antibody against filaggrin produced a cytoplasmic staining of the stratnm granulosum cells like that seen in human beings (KANITAKIS et al. 1988). ACAM against calmodulin gave a faint basal and an irregular subcorneal staining (POX) in porcine skin, whereas in human epidermis only basal keratinocytes were labelled (WOLLINA et al. 1989). The dermis including the basal membrane was labelled by antibodies to collagen type IV, fibronectin and vimentin similar to human skin (cf. MOLL et al. 1986; RAMAEKERS et al. 1983). Dermal vessels were stained by the monoclonal antibody ICAM-l, like human dermal vessels (SIMMONS et al. 1988). On the other hand, antibodies to factor VIII-related antigen and EGF-receptor, which also label human vessels, were non-reactive in pigs. In conclusion, immunohistochemical findings support the reliability of pig skin as a model in biomedical research, which offers the advantage of striking similarities to human skin (MEYER et al. 1978).
Acknowledgements The authors are grateful to Dr. P. JABLONSKI (Canberra, Australia) and Dr. I. WENZ (lena, FRG) for the generous gift of the antibodies BF 8 and ACAM. The technical assistance of Miss SABINE FELDRAPPE is highly appreciated.
References ARCHAMBEAU, J. 0.: Swine skin: A model to evaluate dose recovery from different radiations. Bas. Life Sci. 50, (1989) 9-20. - and G. W. BENNETT: Quantification of morphoplogic, cytologic, and kinetic parameters of unirradiated swine skin: A histologic model. Radiat. Res. 98, (1984) 254-273. CARVER, M. P., P. L. WILLIAMS, and J. E. RIVIERE: The isolated procine skin flap. III. Percutaneous absorption of organophosphates, steroids, benzoic acid, and caffeine. Toxicol. Appl. Pharmacol. 97, (1989) 324-337. DEBUS, E., K. WEBER, and M. OSBORN: Monoclonal cytokeratin antibodies that distinguish simple from stratified epithelia: Characterization on human tissues. Europ. Molec. BioI. Org. J. I, (1982) 1641-1647. DYSON, M., S. YOUNG, C. L. PENDLE, D. F. WEBSTER, and S. M. LANG: Comparision of the effect of moist and dry conditions on dermal repair. J. Invest. Dermatol. 91, (1988) 434-439. GIGI, 0., B. GEIGER, Z. ESHHAR, R. MOLL, E. SCHMID, S. WINTER, D. L. SCHULER, and W. W. FRANKE: Detection of a cytokeratin determinant common to diverse epithelial cells by a broadly cross-reacting monoclonal antibody. Europ. Molec. BioI. Org. J. 1, (1982) 1429-1437. GROVES, D. J., and E. M. TUCKER: The production and application of non-rodent monoclonal antibodies in veterinary science. Veter. Immunol. Immunopathol. 23, (1989) 1-14. HEBDA, P. A.: Stimulatory effects of transforming growth factor-beta and epidermal growth factor on epidermal cell outgrowth from skin explant cultures. J. Invest. Dermatol. 91, (1988) 440-445. HUKKI, J., J. LIPASTI, M. CASTREN, P. PuOLAKKAINEN, and T. SCHRODER: Lactate dehydrogenase in laser incision: A comparative analysis of skin wounds made with steel scalpel, electro cautery, superpulsecontinuous wave mode carbon-dioxide lasers, and contact Nd:YAG laser. Lasers Surg. Med. 9, (1989) 589-594. HUSZAR, M., O. GIGI-LEITNER, R. MOLL, W. W. FRANKE, and B. GEIGER: Monoclonal antibodies to various acidic (type I) cytokeratins of stratified epithelia. Selective markers for stratification and squamous cell carcinoma. Differentiation 31, (1986) 141-153. KANITAKIS, J., A. RAMIREz-BoSCA, A. REANO, J. VIAC, P. ROCHE, and J. THIVOLET: Filaggrin expression in normal and pathologic skin. A marker of keratinocyte differentiation. Virchows Arch. A. Pathol. Anat. Histopathol. 412, (1988) 375- 382.
Porcine skin
91
MEYER, W., and S. GORGEN: Some observations on dermis development in fetal porcine skin. Anat. Anz. 161, (1986) 297-307. - and C. SCHLESINGER: Structural and histochemical aspects of epidermis development of fetal porcine skin. Amer. J. Anat. 176, (1986) 207-219. and K. NEURAND: A comparative scanning electron microscopic view of the integument of domestic mammals. Scanning Microsc. 1, (1987) 169-180. R. SCHWARZ and K. NEURAND: The skin of domestic mammals as a model for the human skin, with special reference to the domestic pig. Curr. Probl. Dermatol. 7, (1978) 39-52. MOLL, R., 1. MOLL, and W. W. FRANKE: Intermedifufilamente als Kriterien bei der Diagnostik von Hauttumoren. Pathologe 7, (1986) 164-174. RAMAEKERS, F. C. S., J. J. G. PUTS, O. MOESKER, A. KANT, A. HUYSMANS, D. HAAG, P. H. K. JAP, C.-J. HERMAN, and G. P. VOOIJs: Antibodies to intermediate filament proteins in the immunohistochemical identification of human tumours: An overview. Histochem. J. 15, (1983) 691-713. RICCIARDELLI, E. J., G. S. GODING, D. A. BrumiT, and C. W. CUMMINGS: Acute blood flow changes in rapidly expanded and adjacent skin. Arch. Otolaryngol. Head Neck Surg. 115, (1989) 182-186. RIVIERE, J. E., K. F. BOWMAN, N. A. MONTEIRO-RIVIERE, L. P. DIX, and M. P. CARVER: The isolated perfused porcine skin flap (IPPSF). 1. A novel in vitro model for percutaneous absorption and cutaneous toxiclogy studies. Fundam. Appl. Toxicol. 7, (1986) 444-453. SIMMONS, P., M. W. MAGKOBA, and B. SEED: ICAM-l, an adhesion ligand ofLFA-l, is homologous to the neural cells adhesion molecule NCAM. Nature 331, (1988) 624-627. TSUKISE, A., and W. MEYER: Histochemistry of complex carbohydrates in the hairy skin of the domestic pig. Histochem. J. 15, (1983) 845-860. WILLIAMS, P. L., and J. E. RIVIERE: Definition of a physiologic pharmacokinetic model of cutaneous drug distribution using the isolated porcine skin flap. J. PharriJ. Sci. 78, (1989) 550-555. WOLLINA, U., R. KLINGER, R. WETZKER, R. REISSMANN, and B. KNOPF: Immunohistologic localization of calmodulin in normal and psoriatic epidermis. Arch. Dermatol. Res. 280, (1989) 497-498. Author's address: Dr. sc. med. U. WOLLINA, Klinik und Poliklinik fur Hautkrankheiten der Friedrich-SchillerUniversitiit Jena, Erfurter StraBe 35, D-O-6900 Jena, BRD.
Departments of Dermatology, University of KOln, FRO* and Jena, FRO**, Department of Plastic Surgery University of Jena, FRO***
Immunohistochemistry of porcine skint) By UWE WOLLINA*'**, UWE BERGER*** and GUSTAV MAHRLE* With one Figure (Received August 6, 1990) Key words: Porcine skin - Immunohistology - Epidermis - Dermis
Abstract The present paper reports immunohistological findings in porcine skin, which were obtained by use of monoand polyclonal antihuman antibodies and either alkaline phosphatase anti-alkaline phosphatase (APAAP) or peroxidase (POX) technique. Epidermal staining was observed with antibodies to keratins (K 8.12, RKSE 60), filaggrin, and calmodulin (ACAM). Staining of connective tissue and vessels was achieved using antibodies to vimentin (V9(l)), collagen type IV, and fibronectin. In general, these antibodies gave a staining pattern similar to that of normal human skin. The similarities of immunoreactivity to poly- and monoclonal antihuman antibodies in porcine and human skin render porcine skin a reliable model in biomedical research.
1. Introduction Skin models are of increasing interest in various fields of biomedical research, such as dermatology, pharmacology, toxicology, surgery, and radiation biology. While most studies have used laboratory animals, e.g. rats, mice, or guinea pigs, there are striking differences to human skin. It has been reported that porcine skin of both domestic or minipigs offers several advantages, because it resembles human skin in its morphologic, histochemical, and cell kinetic qualities (ARCHAMBEAU and BENNETT 1984; MEYER et al. 1978, 1986; MEYER and NEURAND 1987; MEYER and GORGEN 1986; TSUKISE and MEYER 1983). MEYER et al. (1986) reported immunohistological findings in porcine skin using 3 polyclonal antibodies against human keratins, which indicated a common pathway of keratinocyte differentiation in both porcine and human skin. Since monoclonal antibodies to porcine tissue antigens are still lacking (GROVES and TUCKER 1989), we tested a number of mono- and polyclonal antibodies to human epidermal as well as dermal antigens.
2. Material and methods Tissue samples from the thoracic region of 6 minipigs were obtained from the Centre of Animal Research at the Department of Medicine of the University of Jena. After removal, skin specimens were snap frozen in liquid nitrogen and cut at 5 !AJIl. Acetone fixed sections were used for immunostaining. 1) This study was performed during a research fellowship of Dr. U. WOLLINA at the University of KOln, Department of Dermatology.
88
U. WOLLINA et al.
Table. 1. List of primary antibodies Antibody
Characterization
Specificity
Source
Dilution
CAM 5.2 RKSE60
monoclonal IgG2a
keratins 8/18/19 keratin 10
Becton Dickinson Euro-Diagnostics
keratins 13/16
Bio-Marker
keratin 18 filaggrin, profilaggrin vimentin CD 54 EGF-receptor
Boehringer Paesel
1:2 1 :50 1: 100 1 :50 1: 100 1 :5 1 :50
(POX) (POX) (APAAP) (POX) (APAAP) (APAAP) (POX)
1: 10 1 :50 1:500 1 :2000 1:1 1 :50 1:50 1: 100 1: 100
(POX) (POX) (POX) (APAAP) (POX) (POX) (POX) (POX) (POX)
K 8.12 CK2 Filaggrin
monoclonal IgG 1
V9 (1) ICAM-l 29.11 BF 8 ACAM Collagen IV Fibronectin F-Vill-rAg
}
monoclonal IgG2a polyclonal rabbit monoclonal IgG 1 polyclonal rabbit
calmodulin calmodulin collagen type IV fibronectin factor-Vill-related antigen
Monosan Immunotech Sigma Dr. P. JABLONSKI Dr. I. WENZ Biogenesis Dako Dako
The primary antibodies employed are summarized in Table 1. Secondary antibodies used for peroxidase technique (POX) or alkaline phosphatase anti-alkaline phosphatase technique (APAAP) were purchased from Dako (Hamburg, FRG). Immunostaining procedures were performed according to standard protocols. 3-amino-9-ethyl-carbazole was used to visualize the peroxidase activity in POX and naphthol-bi-phosphate served as substrate in APAAP (see also table 1). In controls, the primary antibody was replaced by buffer solution.
3. Results In Table 2, several mono- and polyc1onal antibodies are listed, which stained both human and pig skin antigens. Table 2. Comparative immunostaining of percine and human skin Antibody
Pig Epidermis
CAM 5.2 RKSE 60 K 8.12 CK2 Filaggrin V9 (1) ICAM-l 29.11 BF 8 ACAM Collagen IV Fibronectin F-Vill-rAG
Human Dermis/Vessels
Epidermis
Dermis/Vessels
+
-/-/-
+
-/-/-
-/-
+ +
+
-/-
-/-/-/-
+1+
+
-/+
+ + +
-/-/-/-
+/+ +/+ -/-
+ + +
-/-
+1+ -1+ -1+ -/-/-
+/+
+1+ -1+
Porcine skin
I a lblld 1c
1
89
Fig. 1. Irnrnunostaining of porcine skin with monoclonal antibodies against intermediate filaments and filaggrin. a Basal epidermal staining with antibody K 8.12. b Suprabasal epidermal staining with antibody RKSE 60. c Subcorneal staining with anti-filaggrin. d lrnrnunostaining of epidermal dendritic (Langerhans ?) cells, deflI)al fibroblasts and vessel walls with antibody V9(l). Methods: APAAP for a-c; POX-AEC for d. X 250.
Antibodies to keratins labelled either basal (K 8.12) or suprabasal keratinocytes (RKSE 60) . As in human epidermis antibodies to glandular type keratins, i.e. CAM 5.2 and CK 2, failed to react with porcine epidermis. Anti-filaggrin marked the subcomeal stratum granulosum (Fig. 1 a to c). The polyclonal ACAM against calmodulin produced a faint cytoplasmic staining of basal cells and sometimes of subcomeal cells. The basal membrane was decorated by antibodies to type IV collagen and fibronectin. Dermal vessels were stained with antibodies to ICAM-l, but neither with those to factor VIII-related antigen nor to EGF-receptor. The vimentin antibody disclosed a cytoplasmic staining of epidermal dendritic cells, dermal fibroblasts, and vessel walls (Fig. 1 d).
Discussion Porcine skin has become a reliable model for biomedical research in recent years. It has gained special attention for radiobiologists (ARCHAMBEAU 1989; ARCHAMBEAU and BENNETT 1984), pharmacologists (CARVER et al . 1989; RIVIERE etal. 1986; WILLIAMS and RIVIERE 1989), and surgeons (DYSON eta!' 1988; HEBDA 1988; HUKKI eta!' 1989; RICCIARDELLI et al. 1989). Thus, there is an increasing interest in evaluating epidermal differentiation
90
U. WOLLINA et al.
and skin immunohistology in domestic pigs and minipigs (MEYER and GORGEN 1986; MEYER etal. 1986). The lack of antibodies to porcine skin antigens makes it necessary to search for antihuman antibodies cross-reacting with porcine tissue (cf. GROVES and TUCKER 1989). GIGI et al. (1982) described a broad-spectrum antibody to human cytokeratins (KG 8.13), which was reactive on tissue sections of mouse, cow, and pig. Another monoclonal antibody CK4 against human keratin 18 labelled pig mammary glands (DEBUS et al. 1982). MEYER et al. (1986) reported immunohistological findings on porcine epidermis using 3 different polyclonal antibodies to human cytokeratins. In the present paper, antibodies to human keratins, such as K 8.12 and RKSE 60, labelled porcine epidermis. This suggests the presence of keratins 16 and 10 (HUSZAR etal. 1986; RAMAEKERS etal.1983) in the basal and the suprabasallayer, respectively. Similar staining patterns were observed in human skin. The monoclonal antibody against filaggrin produced a cytoplasmic staining of the stratnm granulosum cells like that seen in human beings (KANITAKIS et al. 1988). ACAM against calmodulin gave a faint basal and an irregular subcorneal staining (POX) in porcine skin, whereas in human epidermis only basal keratinocytes were labelled (WOLLINA et al. 1989). The dermis including the basal membrane was labelled by antibodies to collagen type IV, fibronectin and vimentin similar to human skin (cf. MOLL et al. 1986; RAMAEKERS et al. 1983). Dermal vessels were stained by the monoclonal antibody ICAM-l, like human dermal vessels (SIMMONS et al. 1988). On the other hand, antibodies to factor VIII-related antigen and EGF-receptor, which also label human vessels, were non-reactive in pigs. In conclusion, immunohistochemical findings support the reliability of pig skin as a model in biomedical research, which offers the advantage of striking similarities to human skin (MEYER et al. 1978).
Acknowledgements The authors are grateful to Dr. P. JABLONSKI (Canberra, Australia) and Dr. I. WENZ (lena, FRG) for the generous gift of the antibodies BF 8 and ACAM. The technical assistance of Miss SABINE FELDRAPPE is highly appreciated.
References ARCHAMBEAU, J. 0.: Swine skin: A model to evaluate dose recovery from different radiations. Bas. Life Sci. 50, (1989) 9-20. - and G. W. BENNETT: Quantification of morphoplogic, cytologic, and kinetic parameters of unirradiated swine skin: A histologic model. Radiat. Res. 98, (1984) 254-273. CARVER, M. P., P. L. WILLIAMS, and J. E. RIVIERE: The isolated procine skin flap. III. Percutaneous absorption of organophosphates, steroids, benzoic acid, and caffeine. Toxicol. Appl. Pharmacol. 97, (1989) 324-337. DEBUS, E., K. WEBER, and M. OSBORN: Monoclonal cytokeratin antibodies that distinguish simple from stratified epithelia: Characterization on human tissues. Europ. Molec. BioI. Org. J. I, (1982) 1641-1647. DYSON, M., S. YOUNG, C. L. PENDLE, D. F. WEBSTER, and S. M. LANG: Comparision of the effect of moist and dry conditions on dermal repair. J. Invest. Dermatol. 91, (1988) 434-439. GIGI, 0., B. GEIGER, Z. ESHHAR, R. MOLL, E. SCHMID, S. WINTER, D. L. SCHULER, and W. W. FRANKE: Detection of a cytokeratin determinant common to diverse epithelial cells by a broadly cross-reacting monoclonal antibody. Europ. Molec. BioI. Org. J. 1, (1982) 1429-1437. GROVES, D. J., and E. M. TUCKER: The production and application of non-rodent monoclonal antibodies in veterinary science. Veter. Immunol. Immunopathol. 23, (1989) 1-14. HEBDA, P. A.: Stimulatory effects of transforming growth factor-beta and epidermal growth factor on epidermal cell outgrowth from skin explant cultures. J. Invest. Dermatol. 91, (1988) 440-445. HUKKI, J., J. LIPASTI, M. CASTREN, P. PuOLAKKAINEN, and T. SCHRODER: Lactate dehydrogenase in laser incision: A comparative analysis of skin wounds made with steel scalpel, electro cautery, superpulsecontinuous wave mode carbon-dioxide lasers, and contact Nd:YAG laser. Lasers Surg. Med. 9, (1989) 589-594. HUSZAR, M., O. GIGI-LEITNER, R. MOLL, W. W. FRANKE, and B. GEIGER: Monoclonal antibodies to various acidic (type I) cytokeratins of stratified epithelia. Selective markers for stratification and squamous cell carcinoma. Differentiation 31, (1986) 141-153. KANITAKIS, J., A. RAMIREz-BoSCA, A. REANO, J. VIAC, P. ROCHE, and J. THIVOLET: Filaggrin expression in normal and pathologic skin. A marker of keratinocyte differentiation. Virchows Arch. A. Pathol. Anat. Histopathol. 412, (1988) 375- 382.
Porcine skin
91
MEYER, W., and S. GORGEN: Some observations on dermis development in fetal porcine skin. Anat. Anz. 161, (1986) 297-307. - and C. SCHLESINGER: Structural and histochemical aspects of epidermis development of fetal porcine skin. Amer. J. Anat. 176, (1986) 207-219. and K. NEURAND: A comparative scanning electron microscopic view of the integument of domestic mammals. Scanning Microsc. 1, (1987) 169-180. R. SCHWARZ and K. NEURAND: The skin of domestic mammals as a model for the human skin, with special reference to the domestic pig. Curr. Probl. Dermatol. 7, (1978) 39-52. MOLL, R., 1. MOLL, and W. W. FRANKE: Intermedifufilamente als Kriterien bei der Diagnostik von Hauttumoren. Pathologe 7, (1986) 164-174. RAMAEKERS, F. C. S., J. J. G. PUTS, O. MOESKER, A. KANT, A. HUYSMANS, D. HAAG, P. H. K. JAP, C.-J. HERMAN, and G. P. VOOIJs: Antibodies to intermediate filament proteins in the immunohistochemical identification of human tumours: An overview. Histochem. J. 15, (1983) 691-713. RICCIARDELLI, E. J., G. S. GODING, D. A. BrumiT, and C. W. CUMMINGS: Acute blood flow changes in rapidly expanded and adjacent skin. Arch. Otolaryngol. Head Neck Surg. 115, (1989) 182-186. RIVIERE, J. E., K. F. BOWMAN, N. A. MONTEIRO-RIVIERE, L. P. DIX, and M. P. CARVER: The isolated perfused porcine skin flap (IPPSF). 1. A novel in vitro model for percutaneous absorption and cutaneous toxiclogy studies. Fundam. Appl. Toxicol. 7, (1986) 444-453. SIMMONS, P., M. W. MAGKOBA, and B. SEED: ICAM-l, an adhesion ligand ofLFA-l, is homologous to the neural cells adhesion molecule NCAM. Nature 331, (1988) 624-627. TSUKISE, A., and W. MEYER: Histochemistry of complex carbohydrates in the hairy skin of the domestic pig. Histochem. J. 15, (1983) 845-860. WILLIAMS, P. L., and J. E. RIVIERE: Definition of a physiologic pharmacokinetic model of cutaneous drug distribution using the isolated porcine skin flap. J. PharriJ. Sci. 78, (1989) 550-555. WOLLINA, U., R. KLINGER, R. WETZKER, R. REISSMANN, and B. KNOPF: Immunohistologic localization of calmodulin in normal and psoriatic epidermis. Arch. Dermatol. Res. 280, (1989) 497-498. Author's address: Dr. sc. med. U. WOLLINA, Klinik und Poliklinik fur Hautkrankheiten der Friedrich-SchillerUniversitiit Jena, Erfurter StraBe 35, D-O-6900 Jena, BRD.
