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Biomedical subjects

J E Wilkinson

Publications and source records attributed to J E Wilkinson.

At least 55 records · Page 3Linked to original sources
PubMed1991

Fatal lymphoreticular disease in the scurfy (sf) mouse requires T cells that mature in a sf thymic environment: potential model for thymic education.

Characteristic lesions in mice hemi- or homozygous for the X-linked mutation scurfy (sf) include lymphohistiocytic proliferation in the skin and lymphoid organs, Coombs' test-positive anemia, hypergammaglobulinemia, and death by 24 days of age. The role of the thymus in the development of fatal lymphoreticular disease in the scurfy mouse was investigated. Neonatal thymectomy doubles the life span of scurfy mice, moderates the histologic lesions, and prevents anemia, despite the continued presence of high levels of serum IgG. Animals bred to be nude and scurfy (nu/nu; sf/Y) are viable, fertile, and free of scurfy lesions. Bone marrow from scurfy mice can reconstitute lethally irradiated, H-2-compatible animals but does not transmit scurfy disease. We conclude, from these data, that scurfy lesions are mediated by T lymphocytes that mature in an abnormal (sf) thymic environment.

Animals↗
PubMed1991

Antigen expression in cultured oral keratinocytes from dogs.

Oral keratinocytes from dogs were cultured on either collagen gels or artificial matrices at the air-liquid interface, and the expression of keratinocyte antigens and basement membrane components was determined, using various monoclonal and polyclonal antibodies. Keratinocytes grown on collagen gels expressed pemphigus vulgaris, pemphigus foliaceous, and bullous pemphigoid antigens. Diffuse, suprabasal, and superficial keratinocyte membrane differentiation antigens identified by various monoclonal antibodies also were expressed in a pattern identical to that observed in the native tissue. Laminin and type-IV collagen were deposited at the keratinocyte-collagen interface in a patchy distribution. When synthetic matrices were used, the oral keratinocytes differentiated, but to a lesser extent than cells grown on collagen gels. Antigen expression for cells grown on synthetic matrices was similar to that for cells on collagen, except for failure of the keratinocytes on synthetic membranes to express superficial cell antigens and pemphigus foliaceous antigens.

Animals↗
PubMed1991

X-linked lymphoreticular disease in the scurfy (sf) mutant mouse.

Scurfy (sf) is a spontaneous, sex-linked, recessive mutation that maps to the extreme proximal portion of the X chromosome, about 2 centimorgans from sparse fur (spf). Hemizygotes for sf manifest several clinical disorders, evident at 14 days of age, including scaliness and crusting of the eyelids, ears, and tail, runting, reddening and swelling of the genital papilla, anemia, cachexia, and early death (average, 24 days). Our studies indicate that the phenotype of hemizygous scurfy is not, as has been suggested, a model for human X-linked ichthyosis, but appears to be a disease primarily affecting the lymphoreticular, and possibly the hematopoietic, systems. Gross lesions include marked splenomegaly, hepatomegaly, enlarged lymph nodes, and variable thickening of the ears. The characteristic histologic lesion is a lymphohistiocytic proliferation and infiltration of peripheral lymph nodes, spleen, liver, and skin. In routine hematoxylin and eosin-stained sections, these lesions efface lymph node architecture, thicken the dermis, and form nodular portal infiltrates in the liver. Scurfy lesions characteristically contain a population of large blastlike cells with round to oval nuclei, a vesicular chromatin pattern, and prominent single nucleoli. Mixed perivascular infiltrates of lymphocytes, macrophages, and granulocytes sometimes are found in kidney, heart, pancreas, lung, and mesenteries. There is excessive hematopoiesis in the liver and spleen. Cells expressing B220 or Thy-1 antigens localize to appropriate areas in the lymph nodes and spleen, but are rare in the portal infiltrates and are absent from the skin. There is a marked, polyclonal increase in serum IgG, severe Coombs'-positive anemia, and leukocytosis with atypical mononuclear cells. Scurfy mice are negative for antinuclear antibodies. Despite their morphologically aberrant lymphoreticular system, scurfy mice can exist in a conventional environment without evidence of opportunistic infection. Raising scurfy mice in a specific-pathogen-free environment does not alter disease expression. Thus, while our findings indicate that scurfy disease may be the result of immune dysfunction, it is not a classic immunodeficiency.

Animals↗
PubMed1990

Nd:YAG laser-induced interstitial hyperthermia using a long frosted contact probe.

The heating potential of a closed loop interstitial hyperthermia system employing 1,064 nm laser light in conjunction with a long frosted contact probe was investigated in hind limb muscle of anesthetized dogs. The laser system was an Nd:YAG surgical laser modified with a single channel thermometry unit, a computer, a printer, and a computer-controlled laser exposure shutter. The long frosted laser probe was implanted into the muscle, and 3.12-5.00 Watts of laser power was delivered interstitially. Temperature distribution was measured in three dimensions around the frosted probe. The temperature distributions generated by this technique were satisfactory for producing desired hyperthermia temperatures in an approximately 3.5 cm3 cylindrical tissue volume. A multiple laser delivery system is needed to induce interstitial hyperthermia in large tumors. A significant potential for the long frosted contact probe may be its use in combining interstitial hyperthermia and interstitial photodynamic therapy. Using this technique, both modalities may be delivered while employing the same treatment setup.

Animals↗
PubMed1990

Effects of substrata on the polarization of bovine endometrial epithelial cells in vitro.

Epithelial-cell function requires cellular polarity in which apical membrane surfaces have unique characteristics and cellular organelles are stratified. Physiological investigations of endometrial epithelial cells would be enhanced greatly by the ability of a method to polarize cells in culture. This study investigates the effects of different substrata on polarization of cultured bovine endometrial epithelial cells. Fetal bovine endometrial epithelial-cell lines were developed from explant outgrowth. Epithelial monolayers were subcultured onto amniotic membranes, Millicell-HA membranes, or Millicell-CM membranes coated with rat-tail collagen, Matrigel, laminin, Vitrogen, or fibronectin. Cultures on these substrata were maintained at the air/liquid interface. Cells grown on either collagen-coated or uncoated Millicell membranes also were maintained submerged in medium. Excellent polarized morphology was attained in cultures grown at the air/liquid interface on amniotic membranes and rat-tail collagen-coated membranes. Lectin-binding patterns to apical membranes of polarized epithelial cell cultures paralleled patterns of binding to bovine endometrial surfaces in vivo. Cultures on rat-tail collagen were maintained for several weeks. These methods provide a valuable system for studying the endometrium in vitro.

Animals↗
PubMed1990

Differential expression of cell surface antigens of canine keratinocytes defined by monoclonal antibodies.

Nine monoclonal antibodies (MAb) directed against cell surface antigens of canine keratinocytes define distinct keratinocyte subpopulations owing to the differential expression of these antigens during the process of differentiation and depending on the tissue location of the cells. There was distinct antigenic heterogeneity between the different layers of stratified squamous epithelium and between stratified squamous epithelial of different tissue origin. Two MAb reacted only with antigens expressed by esophageal mucosa. Three MAb bound to antigens on keratinocytes of the suprabasilar and granular layers of stratified squamous epithelia, and they crossreacted with the transitional epithelial cells of the urinary tract. Two MAb reacted with antigens only expressed on differentiated cells, superficially located in the stratified squamous epithelium. The use of these MAb as markers for keratinocytes in studies on the characterization and differentiation of keratinocytes, as well as in tumor diagnosis and allograft transplantation, is discussed.

Animals↗
PubMed1990

Ultrastructural localization of pemphigus vulgaris antigen on canine keratinocytes in vivo and in vitro.

Pemphigus antigens were localized, by use fo immunoelectron microscopy, on canine keratinocytes in vivo on esophageal mucosa and in vitro on established cultured keratinocytes. Convalescent sera from a human being with pemphigus vulgaris and a human being with pemphigus foliaceus reacted with the interdesmosomal cytoplasmic keratinocyte membrane of canine esophagus. Cultured canine keratinocytes expressed the pemphigus vulgaris antigen in a similar pattern, but did not carry the pemphigus foliaceus antigen. The differential presence of cell surface antigens and its relation to various forms of the disease are discussed.

Animals↗
PubMed1989

Role of plasminogen activator in pemphigus vulgaris.

The role of plasminogen activator (PA) in the pathogenesis of acantholysis in canine pemphigus vulgaris (PV) was evaluated using differentiated cultures of canine oral keratinocytes. Both the secreted and cell-associated PA activity in cultured canine keratinocytes were completely inhibited by specific anti-urokinase antibodies. Anti-tissue type PA antibodies did not inhibit either secreted or cell-associated PA activity. Immunoblots and fibrin zymography revealed a single 57,000 molecular weight urokinase-type PA in the conditioned media of the canine oral keratinocytes. Incubation of the differentiated cultures with PV Ig resulted in a significant increased in the levels of PA activity and both canine and human PV Ig were effective at inducing acantholysis typical of that seen in the clinical disease. The addition of urokinase inhibitor to the cultures treated with PV Ig prevented the development of acantholysis. These data strongly support the conclusion that PA is involved in acantholysis which is the cardinal feature of PV.

Acantholysis↗
PubMed1989

Ultrastructure of cultured canine oral keratinocytes.

Keratinocytes from explants of the oral mucosa of dogs were grown in culture for five passages. The ultrastructure of primary cultures and fully developed subcultures passaged 1, 3, and 5 times was examined. At every stage, the cells had the morphologic characteristics of epithelial cells and formed a multilayered squamous epithelium. The basal cells had the characteristics of metabolically active cells, whereas the suprabasal cells and the cells at the media interface expressed many, but not all, of the organelles and cell surface characteristics associated with keratinocyte differentiation. Keratohyalin granules were located in the suprabasal and superficial cells. Cell size and shape and the relationship between cells in the layers also reflected the morphologic characteristics of the parent tissue. Cells maintained this typical structure through all passages and the cultures changed minimally for up to a week after development.

Animals↗
PubMed1988

A disease resembling junctional epidermolysis bullosa in a toy poodle.

A disease resembling junctional epidermolysis bullosa in humans is described in a toy poodle. Shortly after birth, the affected animal developed vesicles and bullae on the pads of the feet and the mucous membranes of the oral cavity. The lesions rapidly increased in number and severity, eventually involving the glabrous skin of the ventral abdomen. Due to the severity of the lesions, the animal was euthanized when it was 48 h old. Histopathologic, ultrastructural and immunohistochemical evaluation defined a minimally inflamed subepidermal vesicular disease with separation occurring at the zona lucida of the basement membrane zone. Laminin and type IV collagen were present at the base of the vesicle.

Animals↗
PubMed1987

Long-term cultivation of canine keratinocytes.

The growth characteristics and morphology of canine keratinocytes grown in vitro were studied. Keratinocytes from canine oral mucosa, ear skin, and ventral abdominal skin were grown in culture either as explants or as dispase/trypsin-derived suspensions in the absence of a feeder cell layer. Cholera toxin and epidermal growth factor were essential to the successful long-term growth and propagation of the cells during multiple passages. Keratinocytes from all tissue sources, either as primary cultures or subcultivated for up to 10 passages, had growth characteristic and morphology similar to that reported in other species. The use of cultured canine keratinocytes should provide a suitable model for comparative in vitro studies of the pathogenesis of dermatologic diseases.

Abdomen↗
PubMed1987

Monoclonal antibodies: cell surface markers for canine keratinocytes.

Plasma membranes were isolated from cultured canine keratinocytes by paraformaldehyde-induced membrane vesiculation. The isolated plasma membrane vesicles retained cell surface antigens (eg, a pemphigus vulgaris antigen). These membrane vesicles were used as an antigen source for the production of monoclonal antibodies. Eight antibodies that had specific reactivity to the cytoplasmic membrane of keratinocytes on frozen sections of canine esophagus were identified by use of an indirect immunoperoxidase method. The stratified squamous epithelium of the esophageal mucosa had 4 staining patterns. When applied to frozen sections of canine skin, lip, and tongue, the antibodies had different tissue specificities for differing stratified squamous epithelia. Using sodium dodecyl sulfate polyacrylamide-gel electrophoresis and the western blot technique, one of the antibodies was specific for a 60-kD cell surface molecule. Therefore, such monoclonal antibodies may be useful in defining heterogeneity between different stratified squamous epithelia, in identifying biologically important surface antigens, or in the diagnosis of tumors.

Animals↗
PubMed1986

Chromosomal radiosensitivity during the G2 cell cycle period and cytopathology of human normal x tumor cell hybrids.

The relationship between tumorigenicity and enhanced chromosomal radiosensitivity during the G2 cell cycle phase was examined through the use of nontumorigenic human cell hybrids and their nontumorigenic and tumorigenic segregants. The hybrid cells were produced by fusion of a normal and tumor cell. The parental lines, including HeLa and three fibroblast lines, one of skin and two of fetal lung origin, were also examined. The tumorigenic lines, which had cytological features associated with clinical cancer, showed a significantly higher incidence of chromatid breaks and gaps following X-irradiation during G2 than the normal skin line or the nontumorigenic hybrids. The hybrids and their nontumorigenic subclones had cytological features which are predominantly found with a benign clinical course and had the G2 chromosomal radiosensitivity more characteristic of the normal parental cells. Like tumorigenic cells, fetal cells exhibited enhanced G2 chromosomal radiosensitivity which could be suppressed in fetal X tumor cell hybrids. This observation suggests that the molecular basis for radiosensitivity in fetal cells differs from that of tumor cells. The enhanced G2 chromosomal radiosensitivity of a tumor cell, which appears to result from deficient DNA repair, is suppressed by fusion with a normal cell. Thus, the radiosensitivity, like tumorigenicity, behaves as a recessive trait. Although a Mendelian analysis is not possible with this material, the segregation of enhanced G2 chromosomal radiosensitivity with the neoplastic phenotype suggests that the two may be genetically linked.

Cell Line↗
PubMed1984

Hemangiosarcoma in a cow.

A 4-year-old cow initially examined because of hindlimb lameness had a waxing and waning course of illness for 31 weeks. Signs included lameness, swelling of the affected limb, and intermittent fever, and anorexia. Radiography and bacterial culturing suggested osteomyelitis. Terminally, there was peracute anemia and dyspnea. The final diagnosis was hemangiosarcoma of the metatarsus, with metastasis to the lungs.

Animals↗
PubMed1982

Human cell hybrids: analysis of transformation and tumorigenicity.

Intraspecific human-human cell hybrids provide a stable model system with which to investigate the genetic control of transformed and tumorigenic phenotypes. Using this system it has been shown that these phenotypes are under separate genetic control. Furthermore, the tumorigenic phenotype can be complemented by fusion of different tumorigenic cells, resulting in nontumorigenic hybrids. This system also provides information on the control of differentiated function. Molecular cytogenetic techniques should reveal the nature of the chromosomal control of neoplastic transformation.

Animals↗