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Biomedical subjects

R Marks

Publications and source records attributed to R Marks.

At least 397 records · Page 22Linked to original sources
PubMed1982

The effect of calcium on the initiation and growth of human epidermal cells.

The effect of the concentration of Ca2+ in the medium on the plating efficiency of human epidermal cells has been investigated. Primary cultures plated onto lethally irradiated mouse embryo fibroblasts showed not only increased colony formation at lowered (0.2 mM) Ca2+ levels but also increased growth rate as indicated by greater colony size. On the other hand, secondary cultures showed little variation in plating efficiency and only small differences in colony size were apparent over the range 0.2-1.64 mM Ca2+. Epidermal growth factor had no effect on the Ca2+ dependence of primary or the Ca2+ independence of secondary cultures.

Calcium↗
PubMed1982

Procollagen localisation in normal, premalignant and malignant lesions of the epidermis.

The distribution of procollagen in normal hyperplastic, preneoplastic or neoplastic human epidermal lesions has been analysed in indirect immunofluorescence tests with the antibodies to procollagen raised in sheep to extracted procollagen, synthesised by newborn rat skin explants in culture. These antiprocollagen antibodies produced indirect immunofluorescence staining only of the papillary dermis of human skin. We reacted serial dilutions of the antibody with each skin lesion and recorded the maximum dilution at which a positive reaction was observed. All lesions examined displayed essentially the same procollagen immunofluorescence pattern. The fluorescence was localised as a fibrillar/diffuse area just under the epidermis. In conditions in which the epidermis is highly convoluted, the fluorescent band was found to follow the pattern of the epidermis and to surround epidermal 'islands' in the deeper dermis. Our observations suggest that in the neoplastic lesions a new dermal topography, resembling the stratum papillare of normal human skin, is found in the deeper dermis surrounding the epidermal islands produced as the epidermal mass increases and invaginates further into the stroma. Malignant epidermal lesions were found to show a positive procollagen immunofluorescent staining at tenfold lower concentrations of the antibody than normal human skin in subepidermal regions.

Animals↗
PubMed1982

Preparation and characterization of the nonionic detergent-soluble proteins of human stratum corneum.

Nonionic detergent-soluble (NIDS) proteins from human stratum corneum have been prepared by the combined action of detergent and mechanical stimulation of normal human skin. SDS-polyacrylamide gel electrophoresis studies revealed approximately 15 components falling into the molecular weight ranges of 10,000-15,000, 24,000-37,000, and 44,000-68,000. Immunization of rabbits with this material gave antisera which demonstrated 3 or 4 antigenic components using 2-dimensional immunoelectrophoresis. Studies with 125I-labeled NIDS protein indicated that the main precipitate on 2-dimensional immunoelectrophoresis was associated with SDS-polyacrylamide gel components of molecular weight 15,000 and 30,000. Indirect immunofluorescence studies on human skin sections revealed localization of NIDS protein antigens throughout the suprabasal epidermis but concentrated in the stratum granulosum and stratum corneum. Localization studies using strips of stratum corneum obtained by the skin surface biopsy technique revealed a pericellular type of distribution of the NIDS protein antigens.

Detergents↗
PubMed1982

Lichenoid solar keratosis--prevalence and immunologic findings.

Solar keratoses (SKs) may show basal cell liquefactive degeneration (BLD) and, when extensive, this can result in a superficial resemblance to lichen planus. The frequency of these phenomena and involvement of immune mechanisms in them have been investigated in this study. The prevalence of lichenoid keratosis (LK) was 6.1% in 212 SKs examined retrospectively and 10.7% in 28 examined prospectively. Histologic features were scored on analogue scales and their interrelationships examined. BLD could not be correlated with epidermal atypia, acanthosis, acantholysis, or inflammatory cellular infiltrate; a negative correlation occurred with parakeratosis. Immunoglobulins and/or fibrin and complement were found by immunofluorescence in 78.8% of the 28 specimens examined prospectively. Three LKs showed similar immunofluorescence findings to ordinary SKs. No circulating antibodies to epidermal structures were detected in patients with SKs. It is concluded that (1) no feature of SKs investigated predisposed to lichenoid change, (2) BLD was a frequent feature in SKs whereas full development of LK occurred much less frequently, and (3) immunoprotein deposits were not related to the development of BLD. Clinically, LKs could not be distinguished from ordinary SKs.

Fibrin↗
PubMed1982

Histamine and epidermal proliferation.

Histamine is liberated in the inflammatory reaction and has been reported to inhibit epidermal cell division in vitro. This study has investigated the effects of histamine and HI and H2 antagonists on epidermopoiesis in vivo in man. No direct stimulatory effect of histamine was detected for normal epidermis. A combination of HI antagonist (chlorpheniramine) and H2 antagonist (cimetidine) led to further increases in epidermal labelling indices in mitotically stimulated epidermis. The administration of HI antagonist alone led to a decrease in mean epidermal thickness. These data suggest that histamine release is unlikely to play a major role in the hyperplasia of inflammatory dermatoses, but that it may be possible to influence epidermal reactions via the HI and H2 receptors.

Adult↗
PubMed1982

A fluorescence photographic photometric technique to assess stratum corneum turnover rate and barrier function in vivo.

A photographic photometric method for objective measurement of fluorescence in skin is described. This method has been used to (a) improve the dansyl chloride method for determining stratum corneum turnover time by making assessments objective and quantitative, and (b) examine the barrier function of the stratum corneum by measuring the concentration of a fluorescent material at different levels within the stratum corneum at different times.

Adult↗
PubMed1982

Involvement of immune mechanisms in the pathogenesis of rosacea.

Twenty-five patients with rosacea were compared with twenty-five control subjects for previous medical history and tests of immune function. Rosacea patients were found to have a higher incidence of disorders of the auto-immune type and were significantly more difficult to sensitize to DNCB than the controls. In addition, twelve of the rosacea patients and eleven other rosacea patients had biopsies which were examined by the direct immunofluorescence technique. In only five was the test negative. In the remainder deposits of IgM and/or IgG and/or complement were found at the dermo-epidermal junction and/or in the dermal collagen. Serum from the rosacea patients was also examined by the indirect technique and in six cases a circulating antinuclear antibody of IgM type was found. It is suggested that altered immune function plays a significant role in the pathogenesis of the disease.

Adult↗
PubMed1982

An animal model for chronic ulceration.

Few techniques are available for the study of persistent ulceration. In this report we describe a suitable animal model. Intracutaneous injection of sodium tetradecyl sulphate (STD) in guinea-pig flank skin caused a reproducibly sized and shaped superficial ulcer that healed approximately three times more slowly than punch biopsies of comparable size. Histological, immunofluorescent and autoradiographic studies showed that it possesses many of the morphological and kinetic features of human stasis ulceration. STD ulcers treated with a streptokinase/streptodornase solution healed with less slough and tended to re-epithelialize more rapidly than controls, but ulcers treated with dextran polymer beads or a stabilized hydrogen peroxide cream healed at the same rate as their control.

Adult↗
PubMed1982

Skin thickness measurement by pulsed ultrasound: its reproducibility, validation and variability.

The reproducibility of the pulsed ultrasound technique for the determination of skin thickness was investigated, using two independent observers. No systematic difference was found and a high correlation was obtained. Studies were also undertaken to validate the pulsed ultrasound technique as a measure of true skin thickness. Skin thickness determined in vitro was found to be greater than when in vivo determinations were made by either the pulsed ultrasound or a xeroradiographic technique, probably due to the release of in vivo tension within the dermis after excision. Skin thickness was found to increase linearly with age up to the age of 20 years and to decrease linearly with age subsequently. Differences in skin thickness between the sexes and in different sites of the body were demonstrated.

Adolescent↗
PubMed1982

Survey of diplomates of the American Board of Dental Public Health, 1980.

A survey was mailed to all active diplomates of the American Board of Dental Public Health in January of 1980 requesting information regarding activities for the period including January 1978 to December 1979. Eighty-two of the then 86 full-time active diplomates responded to the survey. Comparisons with the results of a survey conducted 11 years earlier by Johnson and Bernstein were made with respect to employment, primary activity within employment, and degree of participation in workshops, conferences and seminars. An analysis of results from the two surveys indicates few significant changes in many areas.

Adult↗
PubMed1982

Steroid-induced vasoconstriction: glucocorticoid antagonist studies.

Two currently used steroids (clobetasone butyrate and betamethasone valerate) reproducibly cause vasoconstriction on topical application to human forearm skin. Progesterone, deoxycorticosterone, testosterone, and estradiol, even at 100- to 200-fold higher concentrations, cause no vasoconstriction when applied alone. Applied with clobestasone butyrate, testosterone and estradiol are without antagonist effect; in contrast, both progesterone and deoxycorticosterone antagonize the vasoconstrictor response in a dose-related fashion, with a half-maximal effect at 20-30 times the concentration of clobetasone. Neither progesterone nor deoxycorticosterone affects the vasoconstriction produced by the intradermal injection of epinephrine. In most glucocorticoid-responsive systems, progesterone and deoxycorticosterone are glucocorticoid antagonists, and estradiol and testosterone are inactive. We interpret these studies as evidence that the vasoconstrictor effects of topical steroids are mediated by occupancy of classical glucocorticoid receptors, rather than by nonspecific pharmacological mechanisms.

Adult↗