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Biomedical subjects

I C Mackenzie

Publications and source records attributed to I C Mackenzie.

At least 73 records · Page 4Linked to original sources
PubMed1982

Lectin binding to murine oral mucosa and skin.

Carbohydrates on epithelial cell surfaces of oral mucosa and skin from various anatomical regions of C3H mice were demonstrated with fluoresceinated lectins. With an individual lectin, all tissues showed a similar pattern of binding: most lectins showed binding to the cell surfaces of all nucleated cell layers although that to basal cells was often weaker and was occasionally absent. The corneocytes did not typically bind lectins except that the follicular keratin of the tail showed a uniform and intense fluorescence with several lectins. Basement membrane bound all lectins. The results indicate that detectable changes occur in the cell-surface carbohydrate composition as cells differentiate but that cell-surface carbohydrates do not differ markedly from one region to the next. Lectin binding may provide a convenient method of detecting functional changes in normal cells and in cells which have undergone experimental or pathological changes.

Animals↗
PubMed1982

The diurnal variation of epidermal metabolism.

In previous studies, the rates of epidermal glycolysis and amino acid incorporation were found to parallel rates of mitosis in both the hypoplasia associated with starvation and the hyperplasia produced by treatment with hexadecane. To examine whether similar changes in epidermal metabolism accompany the known diurnal variation in epidermal mitotic activity, the rates of glycolysis and incorporation of amino acids in epidermal sheets from skin samples at various times during a 24-hr period were assayed. These activities were found to parallel the diurnal variation of mitosis demonstrated by metaphase counts. Diurnal variation of metabolism in the suprabasal layers was investigated by examining the relative rates of incorporation of histidine and leucine: it was found that histidine showed a broader peak of activity than that seen for the other measured activities. When epidermal samples were prepared form tissue treated with hexadecane to induce hyperplasia, an increase in metabolic activity and decrease in the amplitude of diurnal variation was observed. The results indicate that the general metabolic activities of the epidermis follow a diurnal pattern similar to that found for mitosis.

Amino Acids↗
PubMed1982

Reactivity of epidermal Langerhans cells to a histochemical method for demonstration of beta-glucuronidase.

Sheets or sections of mouse epidermis reacted by a histochemical method for the enzyme beta-glucuronidase display a subpopulation of dendritic cells which correspond in number and spacing to Langerhans cells demonstrated by reactivity for ATPase or Ia antigens. A similar staining pattern is seen in rat, rabbit, and guinea pig epidermis. In rhesus monkey and human skin, Langerhans cells appear to be reactive for beta-glucuronidase but, as keratinocytes are also reactive, Langerhans cells are not readily identifiable by this method. The thermal stability of beta-glucuronidase differs between strains of mice. Langerhans cells of Balb/C and C3H strains can thus be distinguished by appropriate pretreatment before incubation, a method of potential value for experimental investigations of the origin of Langerhans cells.

Adenosine Triphosphatases↗
PubMed1981

Maintenance of regionally specific patterns of cell proliferation and differentiation in transplanted skin and oral mucosa.

Specimens of mouse ear, footpad and tail skin and palatal, buccal and lingual mucosae were transplanted to protected sites prepared in histocompatible hosts either as intact tissues or recombined after separation of epithelial and connective tissue components using EDTA. Despite maintenance in a protected ectopic site for up to 9 weeks, transplants maintained regionally specific differences in histological appearance and rates of mitotic activity. A diurnal variation in mitotic activity comparable to host control tissues was reestablished.

Animals↗
PubMed1981

Quantitative evaluation of regional differences between epithelia in the adult mouse.

The composition and proliferation of skin from the ear, tail and footpad oral mucosa form the palate, cheek and tongue of adult mice were examined. The thickness of the nucleated cell layer of skin showed an approximately two-fold variation; a similar range was found between that of oral mucosae but that was considerably thicker than skin. No direct correlation between epithelial thickness and the number of nucleated cells was observed. Proliferative activity, assessed following the administration of vinblastine sulphate, and turnover of the epithelium showed a broad range of activities but more rapid in the oral epithelia than in the epidermis, suggesting a relationship between functional stress and proliferative activity. The criteria used clearly distinguish between morphologically different epithelia and should prove useful examining experimentally produced changes in epithelial histodifferentiation.

Animals↗
PubMed1981

The development of ordered structure in neonate rat epidermis.

The establishment of a columnar pattern of organization in rat backskin and earskin was examined by using frozen sections expanded in alkaline buffer and by labeling with 3H-TdR and autoradiography. An adult columnar pattern of organization was established earlier in backskin than earskin. In both tissues the appearance of cell columns was related to a decreasing rate of cell proliferation and, for ear, to a decreasing rate of lateral growth of the epidermis.

Animals↗
PubMed1981

The effects of alpha and beta adrenergic agonists and cyclic adenosine 3':5'-monophosphate on epidermal metabolism.

Continuously regenerating stratified squamous epithelia form an interesting model for examining mechanisms controlling the balance between rates of cell formation and cell maturation and death. In vitro assays of rates of glycolysis and amino acid incorporation of epidermal sheets free from dermal contamination were used to examine rates of metabolism in both normal and hyperplastic epidermis after treatment with various adrenergic agonists and cAMP. Epinephrine and isoproterenol over the concentration range of 1 x 10(-9) to 1 x 10(-5) M depressed the rates of glycolysis and amino acid incorporation in normal epidermis. Dibutyryl cyclic AMP produced a 73 to 78% depression in metabolic activity and its action was enhanced by the addition of theophylline. The alpha adrenergic agonist norepinephrine produced similar reductions. When epidermal samples were treated with hexadecane to induce a mild hyperplasia, depressant effects of isoproterenol and epinephrine were lost, but dibutyryl cyclic AMP and norepinephrine still reduced metabolic activity. The results suggest that adrenergic agents and their putative second messenger cAMP cause reductions in epidermal metabolic activity, an effect similar to their effects on cell proliferation, and that increased rates of proliferation are associated with loss of beta adrenergic responsiveness of the epidermis.

Alkanes↗
PubMed1981

The pattern of cellular organization of human epidermis.

Cell alignment in the stratum corneum of frozen sections of specimens of human skin was examined by light microscopy following expansion of the stratum corneum in alkaline buffer. Some degree of ordered structure was found in all specimens examined but considerable variation existed in precision of cell alignment. The typical degree of cell alignment was less precise than that typically observed in experimental animals.

Adolescent↗
PubMed1980

An examination of the relationship between experimentally altered rates of epidermal proliferations and rates of epidermal metabolism assayed in vitro.

Continuously regenerating stratified squamous epithelia form an interesting model for examining mechanisms controlling the balance between rates of cell formation and cell maturation and death. Previous investigations of epidermal metabolism have been mainly based on single enzyme assays which may not form a reliable guide to changing rates of flux through metabolic pathways. Methods for in vitro assays of rates of glycolysis, protein synthesis and RNA synthesis of epidermal sheets free from dermal contamination were developed and used to examine rates of epidermal metabolism after experimental alteration of rates of epidermal proliferation. Starvation resulted in a 45-53% reduction in the in vivo epidermal labeling index and a 49-56% reduction in glycolysis and incorporation of amino acids assayed in vitro. Induction of epidermal hyperplasia with hexadecane resulted in a 4-fold increase in labeling index, a 6-fold increase in vitro glycolysis and a 3 to 4-fold increase in in vitro assays of incorporation of amino acids and uridine. Hyperplastic epidermis also showed an increased rate of incorporation of histidine (a marker for keratokyalin synthesis) relative to leucine (a marker for basal cell protein synthesis) indicating a change in maturation. The results suggest mechanisms linking rates of cell proliferation and death and indicate the possible value of such assays investigating these mechanisms.

Animals↗
PubMed1979

A method for studying epithelial-mesenchymal interactions in human oral mucosal lesions.

A system has been developed for examining connective tissue influence on keratinization of normal and leukoplakic human oral epithelia. Paired biopsy specimens of normal and leukoplakic mucosa were left intact or were incubated in 1 mM EDTA to permit epithelial-connective tissue separation and various recombinations of the epithelium and connective tissue. The tissues were transplanting to subdermal sites of "nude" (nu/nu) mice and were protected by polyethylene capsules. 44% of implants performed were recovered apparently vital. Preexisting structure was retained after epithelial-connective tissue separation and self-recombination. Cross-recombined specimens showed changes in patterns of keratinization including changes of keratinized leukoplakic epithelium to a non-keratinized type.

Animals↗
PubMed1978

Concanavalin A and ricinus communis receptor sites in normal human oral mucosa.

Fluorescein conjugates of concanavalin A (Con-A) and Ricinus communis fraction 120 (RCA120) were shown to bind to the cell surfaces of basal and spinous cell layers in oral buccal mucosa. Palatal epithelium showed distinct binding to basal and spinous cells; cell membranes in the granular layer occasionally bound Con-A and always RCA120. The ultrastructural localization of Con-A binding sites on exfoliated buccal cells was detected by the Con-A peroxidase staining method. The Con-A receptors were seen on the cell surface in association with the outer leaflet of the plasma membrane. The reaction products appeared as a homogeneous, electron-dense layer containing irregularly distributed globules.

Basement Membrane↗
PubMed1978

Expression of Ricinus communis receptors on epithelial cells in oral carcinomas and oral wounds.

The histological distribution of receptors for Ricinus communis Fraction 1 (RCA1) in oral carcinomas and in oral epithelial cells during wound healing has been studied by use of fluorescein-tagged RCA1. Biopsies from 15 human oral carcinomas and adjacent normal mucosa showed RCA1 receptors at the cell membranes in the basal and spinous layer of the normal epithelium, whereas receptors could not be demonstrated in invading islands of the tumors. In healing oral wounds from eight humans and three monkeys, RCA1 receptors were demonstrated both in normal epithelium adjacent to the wounds and in the epithelial outgrowth from the wound margin. Titrations, however, showed that the epithelial outgrowth reacted more weakly than did the normal adjacent epithelium. These results support previous in vitro studies showing changes in carbohydrate composition of moving normal cells and of malignant cells, a finding that may be of interest in relation to formation of metastases.

Animals↗
PubMed1977

The relationship between expression of epithelial B-like blood group antigen, cell movement and cell proliferation.

Healing wounds in the oral mucosa of rhesus monkeys were examined by an immunofluorescence staining method to demonstrate the distribution of a blood group antigen cross reacting with human group B, and by labelling with tritiated thymidine to localize areas of cell proliferation. Within hours, blood group antigen reactivity was lost from epithelial cells adjacent to the wound margin. Reactivity was absent from the epithelial outgrowth into the wound, but returned with restoration of epithelial continuity. The zone of increased cell proliferation lay adjacent to, but outside of, the area of antigen loss. Antigen loss appeared to be associated with an area of increased cell movement, a finding of interest in relation to reports of antigen loss from epithelial tumors.

ABO Blood-Group System↗
PubMed1976

Examination of topographical gingival anatomy by a filter imprint technique.

The Millipore filter imprint technique was applied to oral cytology using modification of the Papanicolaou and Shorr stains. This technique has the major advantage of demonstrating on each imprint the topographic relationship between cellular zones and also allows for repeated sampling of superficial changes in the same area without tissue. This method provides a wide variety of cytological information about gingival anatomy and demonstrates a number of regions of differing cellular composition.

Alveolar Process↗
PubMed1976

An examination of the cytology of uninflammed and inflammed gingiva using a filter imprint technique.

Filter imprint cytologic specimens were obtained from the gingiva of 41 male dental students following clinical assessment of gingival health using a modification of the Loe gingival index. Nineteen of the specimens were from inflamed, and 22 from uninflamed gingiva. The imprints were fixed and stained by a modification of the Papanicolaou method and macroscopic and microscopic examinations showed that: 1. With increasing severity of clinically detectable gingival inflammation,, there appears to be an increase in the width of the bands of inflammatory cells and epithelial cells adjacent to the gingival margin. 2. An inverse relationship is found between keratinization and inflammation in that the percentages of anucleated epithelial cells was reduced at the gingival margin and significantly reduced midway in the attached gingiva of the inflamed groups. 3. No changes associated with inflammation were noted in cell cytology at the mucogingival junction.

Cytodiagnosis↗