F. Wooding - Academia.edu (original) (raw)
Papers by F. Wooding
PloS one, 2015
The effects of endogenous and synthetic glucocorticoids on fetal lung maturation are well-establi... more The effects of endogenous and synthetic glucocorticoids on fetal lung maturation are well-established, although the role of leptin in lung development before birth is unclear. This study examined mRNA and protein levels of the signalling long-form leptin receptor (Ob-Rb) in fetal ovine lungs towards term, and after experimental manipulation of glucocorticoid levels in utero by fetal cortisol infusion or maternal dexamethasone treatment. In fetal ovine lungs, Ob-Rb protein was localised to bronchiolar epithelium, bronchial cartilage, vascular endothelium, alveolar macrophages and type II pneumocytes. Pulmonary Ob-Rb mRNA abundance increased between 100 (0.69 fractional gestational age) and 144 days (0.99) of gestation, and by 2-4-fold in response to fetal cortisol infusion and maternal dexamethasone treatment. In contrast, pulmonary Ob-Rb protein levels decreased near term and were halved by glucocorticoid treatment, without any significant change in phosphorylated signal transducer ...
The Journal of physiology, 1976
Cell and Tissue Research, 1996
In late pregnancy the sheep fetus requires 3 g of calcium per day, all of which must be transport... more In late pregnancy the sheep fetus requires 3 g of calcium per day, all of which must be transported across the trophoblast epithelium of the placenta. Such high levels of calcium transport across other epithelia are normally associated with the presence of calbindin-D9 or -28k. Our immunocytochemical results show that ovine, bovine and caprine interplacentomal trophoblast have high levels of calbindin-D9k, about eight to ten times more than in the placentomal region. The protein is detectable only in the uninucleate trophoblast cells in sheep and goat, the frequent binucleate cells show none. The calbindin-D9k is also present in the maternal glandular epithelium but not the surface epithelium of the uterus. The cellular distribution of the calbindin-D9k immunoreactivity suggests a soluble protein homogenously distributed through cytosol and nucleoplasm but absent from all organelles and intercellular spaces. In contrast, the uterine milk protein(s) are localised in Golgi cisternae and secretory vesicles in gland cells and in apical small endocytic vesicles and lysosomes in the uninucleate trophectodermal cells. The distribution of calbindin-D9k supports the concept that it mediates the high calcium flux by facilitated diffusion and not via any vesicular, membrane-bounded system.
Journal of Ultrastructure Research, 1978
Several methods were investigated for calcium localization. Only glutaraldehyde fixation followed... more Several methods were investigated for calcium localization. Only glutaraldehyde fixation followed by osmium plus pyroantimonate produces a consistent localization of precipitate in lactating rabbit mammary secretory cells. The precipitate is found only in vesicles and cisternae of the Golgi apparatus and is shown by electron microscope microanalysis to consist of calcium and antimony. The origin of the calcium is briefly discussed.
Journal of Cell Science, 1979
The lactating cow mammary secretory epithelial cell is very active synthetically and contains num... more The lactating cow mammary secretory epithelial cell is very active synthetically and contains numerous very pleomorphic mitochondria. Cup- and ring-shaped mitochondria are frequent and many are extremely elongated. Preferential localization of mitochondria in the basal region, or at the lateral margins of the secretory cell adjacent to intraepithelial monocytes have been observed. Occasional mitochondria show one or several very densely staining cristae with a lattice pattern. Mitochondria are frequently seen closely associated with the tonofilament-desmosomal complex. These structures and associations are present after immersion or perfusion fixation of mammary gland from several breeds of cow; their possible significance is discussed.
Planta, 1969
In parenchyma cells grouped around the stem protoxylem in Pinus pinea characteristic wall ingrowt... more In parenchyma cells grouped around the stem protoxylem in Pinus pinea characteristic wall ingrowths occur. The numerous mitochondria of such cells are very closely associated with the plasmalemma bounding the ingrowths. A functional relationship between this association and salt absorption from the xylem transpiration stream is suggested.
Molecular Reproduction and Development, 1996
Journal of Cell Science, 1968
Chemical and radioautographic studies on sycamore seedling stems have shown an involvement of the... more Chemical and radioautographic studies on sycamore seedling stems have shown an involvement of the Golgi body in cell-wall polysaccharide synthesis from tritiated glucose. Tritiated phenylalanine is shown to be incorporated only into lignin after short incubation times. The patterns of labelling are compared and discussed for the two precursors.
Immunology, 1995
We have developed a novel subcutaneous sponge matrix model in major histocompatibility complex (M... more We have developed a novel subcutaneous sponge matrix model in major histocompatibility complex (MHC) homozygous SLAb/b inbred pigs to study lymphocyte-endothelial cell interactions during inflammation. Polyether sponges were implanted subcutaneously and left for 12 days before injection of proinflammatory agonists. Implanted sponges became highly vascularized and showed markedly increased uptake of i.v.-injected 51Cr-labelled lymphocytes 5 hr after injection of tumour necrosis factor-alpha (TNF-alpha) (3000 U) or phytohaemagglutinin (PHA) (37 micrograms). Lower levels of traffic were seen in sponges 5 hr after injection with interleukin-1 alpha (IL-1 alpha) (3000 U) and no significant traffic occurred in sponges injected with phorbol 12-myristate 13-acetate (PMA) (15 ng) at 5 hr or PHA at 24 hr (compared to sponges injected with medium alone). Electron microscopy of control sponges revealed low numbers of infiltrating leucocytes and relatively 'flat' endothelium. Many more i...
Journal of Dairy Research, 1982
Freeze fractures of the tight junctions at the apices of sheep mammary secretory cells showed tha... more Freeze fractures of the tight junctions at the apices of sheep mammary secretory cells showed that the junction at 72 d of pregnancy was significantly wider than at any later stage. The number of ridges in the junction only increased significantly between 122 and 142 d of pregnancy. The initially even distribution of intramembrane particles across the tight junction changed gradually until in the fully lactating animal there were far more particles on the lateral surface of the plasmalemma. Possible correlations between these changes, the alterations in permeability of the mammary epithelium, and the differences in hormone levels are briefly discussed.
Research in Veterinary Science, 1981
Small quantities of tissue closely resembling brown adipose tissue have been found in pigs aged t... more Small quantities of tissue closely resembling brown adipose tissue have been found in pigs aged two to three months. The tissue, which was taken post mortem from near the great veins in the neck, in the subscapular area and close to the adrenal and thyroid glands, was embedded in connective tissue or white adipose tissue. Examination under the light microscope and electron microscope revealed the following features characteristic of brown adipocytes: multilocular fat: large, round nucleus; numerous mitochondria with cristae; the presence of large amounts of glycogen, and the close proximity of numerous unmyelinated nerve cells with synaptic vesicle filled varicosities. No mitochondrial inclusions were seen. It is suggested that this finding of brown adipose tissue could lead to a better understanding of the control of non-shivering thermogenesis.
Journal of Dairy Research, 1980
Differential counts of electron microscope sections of cell pellets isolated from bovine udder se... more Differential counts of electron microscope sections of cell pellets isolated from bovine udder secretions showed that no secretory epithelial cells and very few ductal epithelial cells were present at any stage. The predominant cell type was the macrophage in dry and lactating cows or the polymorphonuclear leucocyte (PMNL) in colostrum. Lymphocytes were also present but no plasma cells were found. The macrophages took up polystyrene latex particles (as did the PMNL) and adhered to glass in culture. Neither macrophage- nor PMNL-rich cell suspensions produced any increase in free fatty acid levels when incubated with fresh milk.
Journal of cell science, 1971
The morphology of secretion of the fat globule is identical in goat, guinea-pig and cow. The smal... more The morphology of secretion of the fat globule is identical in goat, guinea-pig and cow. The smallest fat droplets, which are found in the basal cytoplasm of the secretory cell, have no membrane separating the lipid from the cytoplasm and no direct association with rough endoplasmic reticulum. In the apex of the cell, fat droplets have numerous peripheral vesicles, most of which appear to be derived from the Golgi body. The progressive fusion of these vesicles results in the extrusion of the fat droplet surrounded by a unit membrane originating partly from the originally peripheral vesicles and partly from the plasmalemma. This membrane bears on its inner surface a zone of dense material which appears to be derived from the cytoplasm, and this is also seen around fat globules in secreted milk. Thus the term apocrine secretion is considered a valid description of the process.
Journal of cell science, 1987
In the sheep, granulated trophectodermal binucleate cells (BNC) appear at implantation 16 days po... more In the sheep, granulated trophectodermal binucleate cells (BNC) appear at implantation 16 days post coitum (dpc) and persist throughout pregnancy. Conventional immunocytochemical techniques at both light and electron microscope levels have indicated the presence of the ovine placental lactogen (oPL) hormone in the granules but no earlier than 22 dpc, when the level was very low. Immunofluorescent studies using glycolmethacrylate sections between 15 and 55 dpc suggest a completely different distribution of oPL restricted to uninucleate cells with none in the BNC. Using the most sensitive method available, immunocytochemistry on ultrathin frozen sections, the results in this paper demonstrate that BNC granules contain oPL at their earliest appearance (16-17 dpc). No significant localization was found in any uninucleate cell. In contrast, another molecule, the SBU-3 antigen, which is demonstrated in BNC granules later in pregnancy, is not present at the earliest stages but appears betw...
Journal of cell science, 1973
In goat mammary tissue under certain conditions perfusion fixation produces a considerable swelli... more In goat mammary tissue under certain conditions perfusion fixation produces a considerable swelling of the rough endoplasmic reticulum and the appearance, in a small number of cells, of intracellular vacuoles which contain lipid globules and casein particles. The morphological evidence suggests that these vacuoles form by fusion of Golgi vesicles. By this process the characteristic structure of the milk fat globule membrane (MFGM) is produced around the lipid globules without any contribution from the plasmalemma. This corroborates the earlier suggestion that normal MFG secretion involves the Golgi vesicles directly.
Journal of cell science, 1988
The location of endoplasmin in the endoplasmic reticulum was investigated by biochemical and immu... more The location of endoplasmin in the endoplasmic reticulum was investigated by biochemical and immunoelectron microscopic analyses. The protein could be obtained in a soluble form by procedures that do not involve the use of any detergents. The soluble protein has the amino- and carboxy-terminal sequences of the intact molecule, showing that it has not been proteolysed. Application of the Triton X-114 phase-separation test does not reveal significant hydrophobicity in the molecule. Immunogold labelling studies on cells with a dilated endoplasmic reticulum (ER) lumen show that endoplasmin is uniformly distributed throughout the lumen, with no evidence of a preferential association with the membrane. These studies clearly demonstrate that endoplasmin is a luminal protein of the ER, i.e. a reticuloplasmin, and not an integral membrane protein.
Placenta, 1999
Using lectin histochemistry on plastic-embedded material, the glycosylation patterns of equine gi... more Using lectin histochemistry on plastic-embedded material, the glycosylation patterns of equine girdle and cup cells, and associated endometrial glands, have been investigated from 37 to 67 days gestation. Results were compared with the glycosylation of the 50-day allantochorionic trophoblast of the established equine placenta that will later form the microcotyledons. The differentiated cup cells, which secrete equine chorionic gonadotropin (eCG), showed a pattern of glycosylation that was distinct both from the progenitor girdle cells and the allantochorionic trophoblast, with granules that bound lectins indicating high levels of alpha2,6 and alpha2,3-linked sialic acid, N-acetyllactosamine and bi/tri antennary non-bisected and bisected complex N-glycan. This is consistent with the known carbohydrate content of eCG. In contrast, the allantochorionic trophoblast at 50 days lacked detectable amounts of sialic acid and showed high levels of tri/tetra-antennary non-bisected complex N-gl...
Immunology, 1995
We have developed a novel subcutaneous sponge matrix model in major histocompatibility complex (M... more We have developed a novel subcutaneous sponge matrix model in major histocompatibility complex (MHC) homozygous SLAb/b inbred pigs to study lymphocyte-endothelial cell interactions during inflammation. Polyether sponges were implanted subcutaneously and left for 12 days before injection of proinflammatory agonists. Implanted sponges became highly vascularized and showed markedly increased uptake of i.v.-injected 51Cr-labelled lymphocytes 5 hr after injection of tumour necrosis factor-alpha (TNF-alpha) (3000 U) or phytohaemagglutinin (PHA) (37 micrograms). Lower levels of traffic were seen in sponges 5 hr after injection with interleukin-1 alpha (IL-1 alpha) (3000 U) and no significant traffic occurred in sponges injected with phorbol 12-myristate 13-acetate (PMA) (15 ng) at 5 hr or PHA at 24 hr (compared to sponges injected with medium alone). Electron microscopy of control sponges revealed low numbers of infiltrating leucocytes and relatively 'flat' endothelium. Many more i...
PloS one, 2015
The effects of endogenous and synthetic glucocorticoids on fetal lung maturation are well-establi... more The effects of endogenous and synthetic glucocorticoids on fetal lung maturation are well-established, although the role of leptin in lung development before birth is unclear. This study examined mRNA and protein levels of the signalling long-form leptin receptor (Ob-Rb) in fetal ovine lungs towards term, and after experimental manipulation of glucocorticoid levels in utero by fetal cortisol infusion or maternal dexamethasone treatment. In fetal ovine lungs, Ob-Rb protein was localised to bronchiolar epithelium, bronchial cartilage, vascular endothelium, alveolar macrophages and type II pneumocytes. Pulmonary Ob-Rb mRNA abundance increased between 100 (0.69 fractional gestational age) and 144 days (0.99) of gestation, and by 2-4-fold in response to fetal cortisol infusion and maternal dexamethasone treatment. In contrast, pulmonary Ob-Rb protein levels decreased near term and were halved by glucocorticoid treatment, without any significant change in phosphorylated signal transducer ...
The Journal of physiology, 1976
Cell and Tissue Research, 1996
In late pregnancy the sheep fetus requires 3 g of calcium per day, all of which must be transport... more In late pregnancy the sheep fetus requires 3 g of calcium per day, all of which must be transported across the trophoblast epithelium of the placenta. Such high levels of calcium transport across other epithelia are normally associated with the presence of calbindin-D9 or -28k. Our immunocytochemical results show that ovine, bovine and caprine interplacentomal trophoblast have high levels of calbindin-D9k, about eight to ten times more than in the placentomal region. The protein is detectable only in the uninucleate trophoblast cells in sheep and goat, the frequent binucleate cells show none. The calbindin-D9k is also present in the maternal glandular epithelium but not the surface epithelium of the uterus. The cellular distribution of the calbindin-D9k immunoreactivity suggests a soluble protein homogenously distributed through cytosol and nucleoplasm but absent from all organelles and intercellular spaces. In contrast, the uterine milk protein(s) are localised in Golgi cisternae and secretory vesicles in gland cells and in apical small endocytic vesicles and lysosomes in the uninucleate trophectodermal cells. The distribution of calbindin-D9k supports the concept that it mediates the high calcium flux by facilitated diffusion and not via any vesicular, membrane-bounded system.
Journal of Ultrastructure Research, 1978
Several methods were investigated for calcium localization. Only glutaraldehyde fixation followed... more Several methods were investigated for calcium localization. Only glutaraldehyde fixation followed by osmium plus pyroantimonate produces a consistent localization of precipitate in lactating rabbit mammary secretory cells. The precipitate is found only in vesicles and cisternae of the Golgi apparatus and is shown by electron microscope microanalysis to consist of calcium and antimony. The origin of the calcium is briefly discussed.
Journal of Cell Science, 1979
The lactating cow mammary secretory epithelial cell is very active synthetically and contains num... more The lactating cow mammary secretory epithelial cell is very active synthetically and contains numerous very pleomorphic mitochondria. Cup- and ring-shaped mitochondria are frequent and many are extremely elongated. Preferential localization of mitochondria in the basal region, or at the lateral margins of the secretory cell adjacent to intraepithelial monocytes have been observed. Occasional mitochondria show one or several very densely staining cristae with a lattice pattern. Mitochondria are frequently seen closely associated with the tonofilament-desmosomal complex. These structures and associations are present after immersion or perfusion fixation of mammary gland from several breeds of cow; their possible significance is discussed.
Planta, 1969
In parenchyma cells grouped around the stem protoxylem in Pinus pinea characteristic wall ingrowt... more In parenchyma cells grouped around the stem protoxylem in Pinus pinea characteristic wall ingrowths occur. The numerous mitochondria of such cells are very closely associated with the plasmalemma bounding the ingrowths. A functional relationship between this association and salt absorption from the xylem transpiration stream is suggested.
Molecular Reproduction and Development, 1996
Journal of Cell Science, 1968
Chemical and radioautographic studies on sycamore seedling stems have shown an involvement of the... more Chemical and radioautographic studies on sycamore seedling stems have shown an involvement of the Golgi body in cell-wall polysaccharide synthesis from tritiated glucose. Tritiated phenylalanine is shown to be incorporated only into lignin after short incubation times. The patterns of labelling are compared and discussed for the two precursors.
Immunology, 1995
We have developed a novel subcutaneous sponge matrix model in major histocompatibility complex (M... more We have developed a novel subcutaneous sponge matrix model in major histocompatibility complex (MHC) homozygous SLAb/b inbred pigs to study lymphocyte-endothelial cell interactions during inflammation. Polyether sponges were implanted subcutaneously and left for 12 days before injection of proinflammatory agonists. Implanted sponges became highly vascularized and showed markedly increased uptake of i.v.-injected 51Cr-labelled lymphocytes 5 hr after injection of tumour necrosis factor-alpha (TNF-alpha) (3000 U) or phytohaemagglutinin (PHA) (37 micrograms). Lower levels of traffic were seen in sponges 5 hr after injection with interleukin-1 alpha (IL-1 alpha) (3000 U) and no significant traffic occurred in sponges injected with phorbol 12-myristate 13-acetate (PMA) (15 ng) at 5 hr or PHA at 24 hr (compared to sponges injected with medium alone). Electron microscopy of control sponges revealed low numbers of infiltrating leucocytes and relatively 'flat' endothelium. Many more i...
Journal of Dairy Research, 1982
Freeze fractures of the tight junctions at the apices of sheep mammary secretory cells showed tha... more Freeze fractures of the tight junctions at the apices of sheep mammary secretory cells showed that the junction at 72 d of pregnancy was significantly wider than at any later stage. The number of ridges in the junction only increased significantly between 122 and 142 d of pregnancy. The initially even distribution of intramembrane particles across the tight junction changed gradually until in the fully lactating animal there were far more particles on the lateral surface of the plasmalemma. Possible correlations between these changes, the alterations in permeability of the mammary epithelium, and the differences in hormone levels are briefly discussed.
Research in Veterinary Science, 1981
Small quantities of tissue closely resembling brown adipose tissue have been found in pigs aged t... more Small quantities of tissue closely resembling brown adipose tissue have been found in pigs aged two to three months. The tissue, which was taken post mortem from near the great veins in the neck, in the subscapular area and close to the adrenal and thyroid glands, was embedded in connective tissue or white adipose tissue. Examination under the light microscope and electron microscope revealed the following features characteristic of brown adipocytes: multilocular fat: large, round nucleus; numerous mitochondria with cristae; the presence of large amounts of glycogen, and the close proximity of numerous unmyelinated nerve cells with synaptic vesicle filled varicosities. No mitochondrial inclusions were seen. It is suggested that this finding of brown adipose tissue could lead to a better understanding of the control of non-shivering thermogenesis.
Journal of Dairy Research, 1980
Differential counts of electron microscope sections of cell pellets isolated from bovine udder se... more Differential counts of electron microscope sections of cell pellets isolated from bovine udder secretions showed that no secretory epithelial cells and very few ductal epithelial cells were present at any stage. The predominant cell type was the macrophage in dry and lactating cows or the polymorphonuclear leucocyte (PMNL) in colostrum. Lymphocytes were also present but no plasma cells were found. The macrophages took up polystyrene latex particles (as did the PMNL) and adhered to glass in culture. Neither macrophage- nor PMNL-rich cell suspensions produced any increase in free fatty acid levels when incubated with fresh milk.
Journal of cell science, 1971
The morphology of secretion of the fat globule is identical in goat, guinea-pig and cow. The smal... more The morphology of secretion of the fat globule is identical in goat, guinea-pig and cow. The smallest fat droplets, which are found in the basal cytoplasm of the secretory cell, have no membrane separating the lipid from the cytoplasm and no direct association with rough endoplasmic reticulum. In the apex of the cell, fat droplets have numerous peripheral vesicles, most of which appear to be derived from the Golgi body. The progressive fusion of these vesicles results in the extrusion of the fat droplet surrounded by a unit membrane originating partly from the originally peripheral vesicles and partly from the plasmalemma. This membrane bears on its inner surface a zone of dense material which appears to be derived from the cytoplasm, and this is also seen around fat globules in secreted milk. Thus the term apocrine secretion is considered a valid description of the process.
Journal of cell science, 1987
In the sheep, granulated trophectodermal binucleate cells (BNC) appear at implantation 16 days po... more In the sheep, granulated trophectodermal binucleate cells (BNC) appear at implantation 16 days post coitum (dpc) and persist throughout pregnancy. Conventional immunocytochemical techniques at both light and electron microscope levels have indicated the presence of the ovine placental lactogen (oPL) hormone in the granules but no earlier than 22 dpc, when the level was very low. Immunofluorescent studies using glycolmethacrylate sections between 15 and 55 dpc suggest a completely different distribution of oPL restricted to uninucleate cells with none in the BNC. Using the most sensitive method available, immunocytochemistry on ultrathin frozen sections, the results in this paper demonstrate that BNC granules contain oPL at their earliest appearance (16-17 dpc). No significant localization was found in any uninucleate cell. In contrast, another molecule, the SBU-3 antigen, which is demonstrated in BNC granules later in pregnancy, is not present at the earliest stages but appears betw...
Journal of cell science, 1973
In goat mammary tissue under certain conditions perfusion fixation produces a considerable swelli... more In goat mammary tissue under certain conditions perfusion fixation produces a considerable swelling of the rough endoplasmic reticulum and the appearance, in a small number of cells, of intracellular vacuoles which contain lipid globules and casein particles. The morphological evidence suggests that these vacuoles form by fusion of Golgi vesicles. By this process the characteristic structure of the milk fat globule membrane (MFGM) is produced around the lipid globules without any contribution from the plasmalemma. This corroborates the earlier suggestion that normal MFG secretion involves the Golgi vesicles directly.
Journal of cell science, 1988
The location of endoplasmin in the endoplasmic reticulum was investigated by biochemical and immu... more The location of endoplasmin in the endoplasmic reticulum was investigated by biochemical and immunoelectron microscopic analyses. The protein could be obtained in a soluble form by procedures that do not involve the use of any detergents. The soluble protein has the amino- and carboxy-terminal sequences of the intact molecule, showing that it has not been proteolysed. Application of the Triton X-114 phase-separation test does not reveal significant hydrophobicity in the molecule. Immunogold labelling studies on cells with a dilated endoplasmic reticulum (ER) lumen show that endoplasmin is uniformly distributed throughout the lumen, with no evidence of a preferential association with the membrane. These studies clearly demonstrate that endoplasmin is a luminal protein of the ER, i.e. a reticuloplasmin, and not an integral membrane protein.
Placenta, 1999
Using lectin histochemistry on plastic-embedded material, the glycosylation patterns of equine gi... more Using lectin histochemistry on plastic-embedded material, the glycosylation patterns of equine girdle and cup cells, and associated endometrial glands, have been investigated from 37 to 67 days gestation. Results were compared with the glycosylation of the 50-day allantochorionic trophoblast of the established equine placenta that will later form the microcotyledons. The differentiated cup cells, which secrete equine chorionic gonadotropin (eCG), showed a pattern of glycosylation that was distinct both from the progenitor girdle cells and the allantochorionic trophoblast, with granules that bound lectins indicating high levels of alpha2,6 and alpha2,3-linked sialic acid, N-acetyllactosamine and bi/tri antennary non-bisected and bisected complex N-glycan. This is consistent with the known carbohydrate content of eCG. In contrast, the allantochorionic trophoblast at 50 days lacked detectable amounts of sialic acid and showed high levels of tri/tetra-antennary non-bisected complex N-gl...
Immunology, 1995
We have developed a novel subcutaneous sponge matrix model in major histocompatibility complex (M... more We have developed a novel subcutaneous sponge matrix model in major histocompatibility complex (MHC) homozygous SLAb/b inbred pigs to study lymphocyte-endothelial cell interactions during inflammation. Polyether sponges were implanted subcutaneously and left for 12 days before injection of proinflammatory agonists. Implanted sponges became highly vascularized and showed markedly increased uptake of i.v.-injected 51Cr-labelled lymphocytes 5 hr after injection of tumour necrosis factor-alpha (TNF-alpha) (3000 U) or phytohaemagglutinin (PHA) (37 micrograms). Lower levels of traffic were seen in sponges 5 hr after injection with interleukin-1 alpha (IL-1 alpha) (3000 U) and no significant traffic occurred in sponges injected with phorbol 12-myristate 13-acetate (PMA) (15 ng) at 5 hr or PHA at 24 hr (compared to sponges injected with medium alone). Electron microscopy of control sponges revealed low numbers of infiltrating leucocytes and relatively 'flat' endothelium. Many more i...