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Biomedical subjects

L E King

Publications and source records attributed to L E King.

At least 19 recordsLinked to original sources
PubMed1992

Comparative evaluation of several DNA binding dyes in the detection of apoptosis-associated chromatin degradation by flow cytometry.

Mouse thymocytes readily undergo apoptosis-associated DNA degradation upon exposure to glucocorticoids or ionizing radiation. It has been previously shown that flow cytometric cell cycle analysis of propidium iodide-stained apoptotic thymocytes results in the appearance of a distinct cell cycle region (the A0 region) below the G0/G1 region. Cells in this region were shown to be undergoing apoptosis, and determination of apoptosis by flow cytometric analysis was proposed as a superior method for evaluating thymocyte apoptosis. In this study, a variety of DNA binding dyes with diverse primary binding mechanisms were evaluated for their ability to detect glucocorticoid and ionizing radiation-induced apoptosis in mouse thymocytes. Apoptotic thymocytes stained with DNA binding dyes from the phenanthridinium, acridine, actinomycin, chromomycinone, anthracycline, and bisbenzimidazole groups all demonstrated clearly defined A0 regions with percentages comparable to those obtained for propidium iodide. These results indicate that the appearance of the A0 region is not dependent on a particular dye binding characteristic and may be the consequence of extensive changes in chromatin structure resulting in a significant degree of dye exclusion.

Acridines↗
PubMed1992

Flow cytometric analysis of the expression of murine B and T surface markers from birth to adulthood.

The proportion of nucleated splenocytes bearing B-lymphocyte markers B220, surface IgM (sIgM) and sIgD, as well as the T-lymphocyte markers Thy 1.2, CD5, CD8a and CD4 were quantitated by flow cytometric analysis (FACS) throughout postpartum development in the A/J mouse. Full expression of B lymphocyte markers was achieved much sooner than expression of T lymphocyte markers. This was especially true for B220, which was found on 8% of all splenocytes at day 5 and reached adult levels (47-50%) by weaning at day 22. Expression of sIgM and sIgD were 13% and 9%, respectively, of all splenocytes at day 5 with mature levels not expressed until day 35 postpartum (approximately 36% of cells were positive for these markers). T lymphocyte markers, on the other hand, did not reach full expression until sexual maturity. For example, Thy 1.2 expression was 8% on day 5 and did not reach mature levels (28-30%) until day 56. CD5 closely paralleled Thy 1.2 expression rising from only 2% on day 5 to 27% by day 56. Likewise, CD8a and CD4 marker development paralleled one another with CD8a rising from 1% on day 5 to 10% by day 56 and CD4 rising from 5% on day 5 to 19% by day 56. These data demonstrate the variability in the time of appearance and rate of maturation of the various lymphocyte cell surface markers during postpartum development. They also serve as a reference to identify alterations in lymphocyte development created by immunodeficiency diseases.

Aging↗
PubMed1992

Increased epidermal growth factor receptors in melanocytic lesions.

BACKGROUND: Epidermal growth factor receptors (EGF/R) have been reported to be absent in melanomas or, in contrast, to be markers for potential malignancy in melanocytic lesions. OBJECTIVE: Our purpose was to evaluate the literature discrepancies regarding the presence of EGF/R in melanocytic lesions and to determine whether EGF/R presence correlates with the potential for malignancy of melanocytic lesions. METHODS: An EGF/R-specific polyclonal antibody was used to study melanomas, dysplastic nevi, congenital nevi, and nevocellular nevi. RESULTS: All melanocytic cell types (nevus and melanoma cells) in the lesions studied had immunoreactive EGF/R. EGF/R immunoreactivity was also observed throughout the epidermal basal to granular cell layers overlying the melanocytic lesions, although dermal fibroblasts were negative. CONCLUSION: The pattern of increased immunoreactive EGF/R in both benign and malignant nevocellular lesions suggests that although EGF/R are not a specific marker of potential malignancy in melanocytic lesions, they may mediate or coordinate growth of keratinocytes and nevus cells.

Adolescent↗
PubMed1992

Extracorporeal photopheresis for the treatment of cutaneous T-cell lymphoma.

BACKGROUND: Many regimens are used for cutaneous T-cell lymphoma (CTCL), but with advanced disease response rates and patient survival are not adequate with any current therapy. Recently extracorporeal photochemotherapy (ECP) was proposed as an alternative therapy. OBJECTIVE: Our purpose is to present the results of ECP in patients with CTCL refractory to other treatments. METHODS: Patients with CTCL received ECP at 3- to 5-week intervals for at least 6 months. All patients except one were in stage T2 (patch/plaque) or higher. Eight patients had extracutaneous disease involving lymph nodes (six patients), bone marrow (five), or Sézary cells (six). The interval between initial symptoms and diagnosis was 5.9 +/- 1.9 years (mean +/- standard error of the mean) and the interval between diagnosis and ECP was 2.2 +/- 0.4 years. RESULTS: A complete response (disappearance of all lesions) was obtained in five patients (25%) and a partial response (disappearance of at least 50% of lesions) in six patients (30%). Four patients (20%) showed stabilization of their disease and five progressed (25%). The only variable that predicted responders versus nonresponders was the number of ECP sessions (p < 0.05 by multivariate logistic regression). In contrast, no separate beneficial effect of adjunctive chemotherapy (p > 0.5) or electron beam therapy (p > 0.1) was found. CONCLUSION: Long-term ECP may be an effective alternative treatment for CTCL refractory to other therapies and is likely to be even more useful when combined with other modalities.

Adult↗
PubMed1992

Acneiform eruption due to eruptive vellus hair cysts.

We have reported a case of eruptive vellus hair cysts, a rare type of acneiform eruption. Patients with unusual or refractory acneiform eruptions may have any of a variety of non-acne-vulgaris lesions. For this reason, biopsy and culture of these lesions may be helpful in establishing a correct diagnosis and determining proper treatment.

Acne Vulgaris↗
PubMed1992

Modulation of epidermal growth factor receptors in psoriatic lesions during treatment with topical EGF.

Active psoriatic lesions have increased EGF/TGF alpha receptors, historically known as the EGF-R. This increase is due to their persistence into the outer parakeratotic layers as measured by autoradiography, immunohistochemistry, and mRNA assays. When psoriatic lesions in patients resolve due to therapy with different modalities, the EGF-R persistently expressed in the outer layers of the epidermis either disappear or resume a basal location presumably due to receptor downregulation. To test whether EGF could downregulate EGF-R and biologically affect psoriatic epidermis, split-thickness skin grafts of active psoriatic lesions were sutured onto the dorsal surface of nude mice. After 3 weeks, the mice were treated daily for a 6-week period with placebo, or 10 or 50 micrograms/ml EGF. Immunostaining showed persistent EGF-R in all epidermal layers in the untreated, placebo-, and 10 micrograms/ml EGF-treated groups. Those grafts receiving a high dose of EGF (50 micrograms/ml) showed either no immunoreactive EGF-R or faint basilar staining. As an additional check for functional activity of the EGF-R, an abundant substrate for this receptor, PLC-gamma 1 was also evaluated following EGF treatment. A similar distribution and modulation pattern following treatment were observed in the grafts immunostained for PLC-gamma 1, suggesting that exogenous EGF treatment affected metabolic pathways subsequent to ligand receptor binding. Morphologic alterations characteristic of a regressing psoriatic phenotype (a decrease in acanthosis, thickness, and the resumption of the orthokeratotic mode of differentiation) were noted in those lesions receiving the 50 micrograms/ml EGF treatment. This study indicates that persistent EGF-R in psoriasis vulgaris are biologically active in vivo and may serve a pivotal role in the regulation of psoriatic lesions.

Administration, Topical↗
PubMed1992

Quantitative determination of EGF-R during epidermal wound healing.

Little is known about the intrinsic regulation of growth factors of cytokines during the normal epidermal wound-healing processes in skin. A simplified model of wounding (tape stripping to remove the stratum corneum) was used to study the role of epidermal growth factor receptors (EGF-R) in this process. Although the dynamics of EGF-R in epidermal wound healing have not been determined, the immunoreactive EGF-R that are present presumably play an active role. Prior studies show that 1) EGF-R are present in increased numbers in proliferative skin diseases; 2) a hypertrophic epidermis, closely resembling normal wound healing, is induced in mouse skin by EGF injections; and 3) exogenous topical EGF potentiates wound healing. The number of immunoreactive receptors as measured by an enzyme-linked immunosorbent assay (ELISA) and histologic methods increased prior to an increase in epidermal thickness, total protein, and DNA content. This early increase in the levels of EGF-R was followed by a sharp decline in EGF-R and subsequent decline in epidermal thickness (hypertrophy), total protein, and DNA levels. Alterations in the temporal sequence in these parameters indicate that the EGF-R-mediated signaling systems play an active role in epidermal wound repair.

Animals↗
PubMed1992

Altered distribution of phospholipase C-gamma 1 in benign hyperproliferative epidermal diseases.

Phospholipase C-gamma 1 (PLC-gamma 1) is a well characterized substrate for the epidermal growth factor receptor tyrosine kinase and has been implicated in the intracellular biochemical signaling cascade which occurs following stimulation of cells with epidermal growth factor. The in vivo localization of PLC-gamma 1 was examined by immunohistochemistry in sections of normal human skin and in skin sections from a diverse series of hyperproliferative epidermal conditions (psoriasis, seborrheic keratoses, acrochordons, and margins near second-degree burns). Immunoreactive PLC-gamma 1 was detected only in the basal compartment of normal skin but was readily detectable in both the basal and outer epidermal compartment in hyperproliferative skin conditions. In addition, immunoreactive PLC-gamma 1 colocalizes with immunoreactive epidermal growth factor receptor in both normal and hyperproliferative epidermis.

Amino Acid Sequence↗
PubMed1992

Epidermal growth factor receptors in idiopathic and virally induced skin diseases.

The altered distribution of epidermal growth factor receptors (EGF-R) in hyperproliferative skin lesions such as psoriasis vulgaris, seborrheic keratoses, acanthosis nigricans, ichthyosis, and others implies aberrant control of growth/proliferation by epidermal growth factor (EGF), transforming growth factor alpha (TGF alpha), and other growth factors/cytokines. Whether overexpression of EGF-R: 1) correlates with epidermal proliferation, 2) serves as a hallmark of specific dermatoses, or 3) is due to modulation by multiple growth factors remains unclear. To correlate distributions of EGF-R with in vivo proliferative status, two benign diseases of unknown etiology, seborrheic keratoses and acrochordons (skin tags), were examined using EGF-R immunolocalization and 125I-EGF binding techniques. Lesions documented as growing by clinical criteria or 5-bromodeoxyuridine incorporation (a measure of cell proliferation) were compared to nongrowing lesions of the same type. To correlate distributions of EGF-R to specific dermatoses, skin diseases of viral etiology (verruca vulgaris and molluscum contagiosum) were also probed by EGF-R immunolocalization and 125I-EGF binding. Elevated immunostaining for EGF-R and 125I-EGF binding sites were associated with actively growing seborrheic keratoses and skin tags whereas normal patterns of immunostaining and 125I-EGF binding were seen in nongrowing seborrheic keratoses and skin tags. Viral diseases showed unique patterns. No EGF-R were detected in verruca vulgaris. Molluscum contagiosum lesions showed intense EGF-R in basal keratinocytes and no EGF-R in virally infected cells. Thus elevations in EGF-R show a positive in vivo correlation with proliferation in at least two differing benign diseases of the epidermis. The decreased levels of EGF-R in virally infected lesions suggests that EGF-R may show unique patterns for specific dermatoses and are not universally elevated in benign hyperproliferative skin disorders.

Cell Division↗
PubMed1991

Epidermal growth factor and its receptor in the developing human nervous system.

Recent data suggest that epidermal growth factor and epidermal growth factor receptors (EGF/EGF-R) are present and functional in neurons within the central nervous system. Previously, EGF was detected in developing and mature rat brain and cerebrospinal fluid. Also, EGF-R was documented in discrete locations in normal adult human brain, as well as in senile plaques associated with Alzheimer's disease. Using two polyclonal sera, anti-EGF and anti-EGF-R, in conjunction with immunohistochemical staining, we examined formalin-fixed, paraffin-embedded neural tissues from 10 autopsied, human brains. These specimens were collected from patients who died during various stages of development ranging from 27 weeks of estimated gestational age to 63 years of age. Immunostaining for EGF and EGF-R was detected in hippocampal pyramidal cells. Purkinje cells, large multipolar neurons of the dentate nucleus, anterior horn cells, dorsal root ganglion cells, cells of the dorsal nucleus of Clark, intermediolateral column cells and ependymal cells. Positive binding studies with 125I-EGF confirmed that numerous EGF receptors are unoccupied, assessable, and available for interactions with potential ligands such as EGF and TGF alpha in developing rat brains. It appears that EGF and/or EGF-R may play a role during maturation and differentiation of the human central nervous system.

Adolescent↗
PubMed1991

Flow cytometric analysis of the phenotypic distribution of splenic lymphocytes in zinc-deficient adult mice.

Many immunodeficiency states create an imbalance in the ratio of T cells to B cells or in the subsets of lymphocytes found within these two major classes. A 30-d period of suboptimal intake of zinc often caused a 50% decrease in the total number of splenic lymphocytes in young adult mice. One- and two-color flow cytometric analysis was made of the residual splenocytes of the zinc-deficient mice to determine whether the deficiency had also altered the composition or phenotypic distribution of any of the major subsets of T cells or B cells. Marginally zinc-deficient mice had a normal ratio of T cells to B cells with no notable change in the subsets of lymphocytes making up these two classes. Severely zinc-deficient mice that exhibited a significant degree of parakeratosis demonstrated a 20% increase in the overall ratio of T helper to T suppressor/cytotoxic cells as well as a modest decline in the percentage of B cells (5-8%). The latter decrease was not in the B cells bearing immunoglobulin M or D but in the minor subsets bearing other immunoglobulin isotypes. Thus it seems that, whereas zinc deficiency caused significant reductions in the total numbers of splenic lymphocytes, it caused no significant change in the composition of the splenic lymphocytes except in the most severe cases.

Animals↗
PubMed1991

Evaluation of glucocorticoid-induced DNA fragmentation in mouse thymocytes by flow cytometry.

The ability of glucocorticoids to induce apoptosis or programmed cell death in mouse thymocytes is well-established. Measurement of apoptosis-associated internucleosomal DNA fragmentation through determination of the percentage of fragmented DNA by electrophoresis or centrifugation of whole cell lysates is by far the most common means of quantifying apoptosis. Since these methods measure DNA fragmentation in whole cell lysates rather than intact cells, they have severe limitations, particularly with heterogeneous cell populations. When mouse thymocytes were incubated with glucocorticoids, fixed, stained with propidium iodide and analysed flow cytometrically for cell cycle distribution, a distinct subpopulation of cells was observed to form below the G0/G1 region, denoted as the A0 region. The presence of cells in this region was consistent with the presence of internucleosomal DNA fragments as determined by gel electrophoresis. Inhibitors of transcription, translation and endonuclease activity, and a glucocorticoid receptor antagonist prevented accumulation of cells in this region. Irradiation of mouse thymocytes also produced a population in the A0 region. Cells in this region are believed to have undergone glucocorticoid-induced DNA fragmentation. This method represents a useful alternative to whole cell lysate assays, since apoptosis can be evaluated on an individual cell basis.

Animals↗
PubMed1991

Treatment of cutaneous sarcoidosis with chloroquine. Review of the literature.

Systemic corticosteroids may be either contraindicated or not efficacious in treating the cutaneous manifestations occurring in 20% to 35% of patients with systemic sarcoidosis. Chloroquine phosphate has been reported to be a valuable alternative therapy for cutaneous lesions of sarcoidosis. With a judiciously determined daily dosage and regular 6-month ophthalmologic follow-up examinations, the risk of developing retinopathy can be avoided, because the daily dosage rate rather than total dose accumulation determines the development of chloroquine-induced retinopathy. We reviewed the efficacy and safety of chloroquine and its role in the treatment of cutaneous sarcoidosis.

Chloroquine↗
PubMed1990

Increased epidermal growth factor receptors in seborrheic keratoses and acrochordons of patients with the dysplastic nevus syndrome.

Seborrheic keratoses and acrochordons may change in biologic behavior with pregnancy or during treatment with sex steroids. Because epidermal growth factor receptor localization may change in hyperproliferative skin diseases, we compared epidermal growth factor receptor immunolocalization in seborrheic keratoses and acrochordons from women who were or were not pregnant or taking oral sex steroid hormones. Epidermal growth factor receptor was further investigated in growing and quiescent seborrheic keratoses and acrochordons from women with and without the dysplastic nevus syndrome. The epidermal growth factor receptor concentration was strikingly elevated in suprabasilar keratinocytes of growing seborrheic keratoses and acrochordons from patients with the dysplastic nevus syndrome who were pregnant or taking sex steroid hormones and less elevated in growing seborrheic keratoses from other patients. In contrast, the epidermal growth factor receptor distribution pattern in acrochordons did not correlate as well with the history of growth of these lesions in normal patients. These data suggest sex steroids may affect epidermal growth factor receptor metabolism in benign epidermal hyperproliferative lesions, particularly in patients with the dysplastic nevus syndrome.

Contraceptives, Oral, Hormonal↗