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R L Dimond

Publications and source records attributed to R L Dimond.

At least 55 records · Page 3Linked to original sources
PubMed1981

Lysosomal enzymes possess a common antigenic determinant in the cellular slime mold, Dictyostelium discoideum.

Antisera have been prepared against two lysosomal enzymes of the cellular slime mold, Dictyostelium discoideum. The two purified enzyme preparations used for immunization, N-acetylglucosaminidase and beta-glucosidase-1, show no cross-contamination with each other and no significant contamination by other lysosomal enzymes. However, antisera raised against either enzyme bind equally well to seven different lysosomal enzymes and show no preference for the enzyme against which they were raised. A total of 10 different antisera have been examined and all show similar results. Preadsorption of antisera with either purified enzyme removes all antibody activity against the other enzyme. Evidence is presented which indicates that the same species of antibodies are responsible for the precipitation of seven lysosomal enzymes. These data are discussed in terms of the proposal that the antigen that is shared by the lysosomal enzymes is a post-translational modification of the enzyme proteins. We have sought to further characterize the distribution of this common antigen among cellular proteins. We show that N-acetylglucosaminidase and beta-glucosidase-1 represent less than 5% of the total common antigen containing proteins in the cell. Precipitation of 35S-labeled cellular proteins from vegetative cells indicates that as much as 15-30% of the total cell protein may possess the common antigen. Preadsorption experiments confirm that all of the proteins immunoprecipitated in these experiments are recognized by the same antibodies that precipitate the lysosomal enzyme activities. Most of the labeled proteins are secreted into the medium along with the lysosomal enzyme activities during axenic growth. During the developmental phase of the life cycle of Dictyostelium, the total amount of the common antigen decreases about 2-fold relative to total cell protein. However, the synthesis of antigenic proteins continues throughout most of development.

Acetylglucosaminidase↗
PubMed1981

Hereditary epidermolytic palmoplantar keratoderma.

We describe herein a patient in whose family 11 of 20 members have a palmoplantar keratoderma. The pathologic findings in the proband were those of epidermolytic hyperkeratosis. As in the other families described, the disease was found to be inherited as an autosomal dominant trait. All involved family members had hyperkeratosis of the palms and soles as infants. Light microscopy showed hyperkeratosis, hypergranulosis with large irregular keratohyalin granules, and large clear spaces in the cells of the granular and upper spinous layers. Our electron microscopic findings showed that the clear spaces were areas of cytoplasm filled with a fibrillar material and cellular organelles; abnormal clumps of tonofilaments and keratohyalin were also present. We consider this disorder to be a form of keratoderma rather than a localized ichthyosis.

Adult↗
PubMed1979

Harlequin ichthyosis with epidermal lipid abnormality.

An infant with phenotypic harlequin ichthyosis survived for nine months, then died a crib death. At autopsy, an enlarged, but structurally normal, thymus was found. Light microscopically, the epidermis showed massive hyperkeratosis and variable parakeratosis, and a stain for neutral fat was positive in the upper epidermis and stratum corneum. Electron microscopic study disclosed crystals resembling cholesterol and masses of autophagic vacuoles, many of them glutted with lipid, deposited within cells of the stratum corneum. Biochemically, cholesterol and triglyceride levels in the stratum corneum were sharply elevated (19.8 and 32.0 mg/g of dry weight, respectively). A defect in epidermal lipid metabolism is postulated.

Autopsy↗
PubMed1978

Enzymatic basis of typical X-linked icthyosis.

Steroid sulphatase activity was determined in cultured fibroblasts from 25 individuals with X-linked ichthyosis from four countries. All those with X-linked disease had markedly reduced enzyme levels compared with controls and patients with other types of ichthyosis. X-linked ichthyosis seems to be the result of a common mutation affecting the expression of steroid-sulphatase activity.

Adult↗
PubMed1978

The epidermolytic toxin of Staphylococcus aureus: its failure to bind to cells and its detection in blister fluids of patients with bullous impetigo.

Radioiodinated staphylococcal epidermolytic toxin was found not to bind to erythrocytes, blood leukocytes, trypsin-dispersed keratinocytes, epidermis or whole skin. Moreover the toxin could not be found to bind to murine epithelia by indirect immunofluorescence methods. However, the toxin, measured by radioimmunoassay, could be eluted from the skin of mice undergoing epidermolysis following intraperitoneal injection of toxinogenic Staphylococcus aureus. Furthermore, epidemolysin was measured in the blister fluid of 3 of 5 children with bullous impetigo but not in blister fluid from control patients with other blistering eruptions. Thus epidermolysin has been demonstrated to be present in lesions of the staphylococcal epidermolytic toxin syndrome but its mechanism of action does not involve binding to cells.

Animals↗
PubMed1977

The staphylococcal scalded skin syndrome. An experimental histochemical and electron microscopic study.

Histochemical and electron microscopic studies were carried out on the newborn mouse model of the staphylococcal scalded skin syndrome to investigate the mechanism of action of the staphylococcal epidermolytic toxin that causes it. Histochemical studies showed that an intra-epidermal split develops below the subcorneal zone which is rich in catabolic enzymes (the so-called esterase-acid phosphatase-rich band). However, histochemical alterations in the enzyme pattern could not be demonstrated. The earliest change revealed by electron microscopy was a widening of the intercellular space, with the formation of microvilli at the level between the stratum spinosum and stratum granulosum where the split later occurs. A clearing of the peripheral cytoplasm along the cell membranes was also revealed. In pre-split areas, adhesion between cell membranes of adjacent cells seems to be lost; desmosomes continue to hold the cells together but the split develops when these are broken by mechanical pressure. Later, damaged cell membranes may be seen. Extracellular keratinosomes remain unchanged. Although these findings do not agree with the already divergent results of other studies, they help support the findings of all groups that cases of the Lyell syndrome produced by staphylococci do not occur through necrolysis; it is therefore inappropriate to continue applying the term 'toxic epidermal necrolysis' to such cases.

Animals↗
PubMed1977

[Staphylogenous Lyell's syndrome].

The scalded skin syndrome or Lyell syndrome can now be divided into two distinct forms. One form is associated with staphylococci that are usually phage group II Staphylococcus aureus, are penicillin resistant, and produce a protein exotoxin which produces epidermolysis by causing a split to develop in the epidermis between the stratum granulosum and the stratum spinosum. The other form is associated usually with drug reactions and is characterized by necrosis of the epidermis with a split between epidermis and dermis. The staphylococcal Lyell syndrome should be treated with penicillinase resistant antibiotics and not with corticosteroids; the non-staphylococcal form of the Lyell syndrome often requires systemic corticosteroids. Therefore the correct diagnosis must be established early. This is possible since the histopathology of the two forms is different.

Adolescent↗
PubMed1976

Structure and function of beta-blucosidases in Dictyostelium discoideum.

There are two isozymes of beta-glucosidase in developing cells of Dictyostelium discoideum. A procedure for screening large numbers of clones for beta-glucosidase activity was utilized to obtain mutations which directly affect the activity. We recovered seven strains which lack both isozymes and four strains with residual activity in which enzymatic and physical properties of both isozymes are altered. Beta-Glucosidase appears to act as a block to selfing in macrocyst formation as shown by the fact that ssite mating type to form macrocyst-like structures. Immunological evidence utilizing antisera prepared against purified beta-glucosidase-1 demonstrates that most of the glycosidases in Dictyostelium discoideum share a common antigenic determinant which appears to be added post-translationally. The two isozymes of beta-glucosidase share common protein subunits but the antigenic determinant is either lacking or masked in beta-glucosidase-2. This may account for some of the enzymatic and physical differences between the two isozymes.

Chromatography, Affinity↗
PubMed1976

The skin of the giraffe.

The skin of the giraffe has the same general histological structure as that of other mammals, but there are notable features. The skin is heavily pigmented with the epidermis, pilary canals, and the outer cell layer of the apocrine duct richly melanized. Furthermore, melanotic dendritic cells are frequently found in the sebaceous glands, the entire length of the external root sheath, and the secretory tubules of the apocrine glands. The thick skin has a papillary dermis that extends to just beneath the secretory coils of the apocrine glands and bulbs of hair follicles and an equally thick reticular layer below these structures. The hair follicles do not grow in clusters, and with some regional variations, have associated sebaceous glands, apocrine glands, and arrectores pilorum muscles. Only the large hairs have a prominent medulla. In such specialized regions as the eyelids, nose, and lips, the apocrine glands are surrounded by cholinesterase-reactive nerves but the glands on the general body surface are not. The only specialized nerve receptors are hair follicle end organs found on every hair of the eyelids, nose, and lips, but only rarely elsewhere.

Animals↗