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Biomedical subjects

A Tosca

Publications and source records attributed to A Tosca.

At least 19 recordsLinked to original sources
PubMed1994

Differences in the G/total actin ratio and microfilament stability between normal and malignant human keratinocytes.

The state of polymerization of actin and the organization of actin filaments is widely believed to be related to cellular transformation. Since the intracellular monomer (G) and filamentous (F) actin content reflects the state of microfilament polymerization, we measured the G/total actin ratio in primary cultures of normal and malignant human keratinocytes. In normal keratinocytes the mean value of this ratio was 0.30 +/- 0.03 (mean +/- SE, n = 15), while in basal cell carcinoma (BCC) keratinocytes it was 0.49 +/- 0.03 (n = 8) and in squamous cell carcinoma keratinocytes (SCC) 0.5 +/- 0.07 (n = 4), indicating a 1.7-fold increase of the G/total actin ratio in malignant cells. These results imply that the proportion of polymerized actin is decreased markedly in malignant keratinocytes, suggesting alterations of microfilament structures which probably occur during the transformation process. This was supported by the morphological changes of microfilament structures as assessed by fluorescence microscopy. A different distribution of actin filaments in normal and malignant cells became evident; stress-fibres were converging in patches at several points in SCC cells, when compared to normal keratinocytes. Furthermore, incubation of normal and malignant keratinocytes with cytochalasin B indicated differences in the resistance of their microfilament networks. After 1 h exposure to 10(-6) and 10(-5) M cytochalasin B, microfilaments in normal cells appeared to be less affected than their counterparts in neoplastic cells. Even in a high excess of cytochalasin B (10(-4) M), normal keratinocytes preserved their shape, while both basal cell and SCC were totally disrupted.(ABSTRACT TRUNCATED AT 250 WORDS)

Actin Cytoskeleton↗
PubMed1994

Typing of human papillomaviruses in condylomata acuminata from Greece.

DNA samples from recurrent condylomata acuminata biopsies of Greek males and females were examined for the presence of human papillomavirus (HPV) DNA using high-stringency Southern blot hybridization analysis. Of the twenty-six biopsies, 25 were positive for the HPV 6/11-related DNA sequences, and when further analyzed with the polymerase chain reaction (PCR) the HPV-negative biopsy was also positive for HPV 6/11 DNA. Nineteen specimens were further characterized based on their Pstl restriction endonuclease hybridization pattern. Twelve biopsies were positive for HPV 6a, one biopsy was positive for HPV 11a, and one biopsy was positive for HPV 6c DNA. Three specimens contained HPV 6/11 related DNA that gave an unusual Pstl pattern, and one specimen appeared to represent a multiple HPV infection containing HPV 6/11- and HPV 31/35/39-related sequences. Finally, one sample contained a mixture of HPV 6a DNA and an HPV 6a-like genome. Biopsies were also taken from adjacent apparently normal tissue, 0.5 cm away from the lesion, in 19 of the patients. Only one of these was found to be positive for HPV 6a DNA by Southern blot analysis.

Adult↗
PubMed1994

Photophysical characterization of hematoporphyrin incorporated within collagen gels.

Physical properties of hematoporphyrin-enriched collagen gels relevant to the photodynamic treatment of cancer are characterized. The incorporation of the sensitizer within the gels does not affect either the structure of the gel or the absorption and fluorescence spectra of the sensitizer. The gel-embedded sensitizer photodegrades efficiently with the formation of a product emitting near 635 nm. Differences in the collagen scattering are observed following sensitization vs. prolonged irradiation with Ar+ laser, indicating contrasting structural modifications effected to the biopolymer matrix in the two cases. The results correspond well to in vivo observations, suggesting that hematoporphyrin-enriched collagen gels may be appropriate systems for modeling the influence of the semisolid nature of tissues, and in particular of the tumour stroma collagen, on the photodynamic phenomenon.

Collagen↗
PubMed1994

Mycosis fungoides: expression of C-myc p62 p53, bcl-2 and PCNA proteins and absence of association with Epstein-Barr virus.

The expression of C-myc p62, bcl-2, p53, PCNA and EBV-encoded LMP-1 proteins was studied by immunohistochemistry on paraffin-embedded skin specimens from 14 patients with early stage (premycotic erythema and second stage plaques) mycosis fungoides (MF), 21 patients with advanced stage MF (third stage plaques and tumors), 3 patients with Sezary's syndrome (SS) and 3 patients with pleomorphic medium and large cell cutaneous T-cell lymphomas (PML-CTCL). All 41 cases were also screened for the presence of EBV by using RNA in situ hybridization with EBER 1/2 oligonucleotides. Increased expression of C-myc p62, p53 and PCNA proteins was found in PML-CTCL and advanced stages of MF as compared to early stages of MF. These results suggest a relationship between levels of C-myc p62, p53 and PCNA proteins and aggressiveness of the cutaneous T-cell lymphomas. Furthermore, C-myc p62 and bcl-2 proteins were found to be frequently coexpressed in the present series. In view of the background information from in vitro findings and animal models that cooperation of C-myc and bcl-2 is important for lymphomagenesis, our results suggest that coexpression of these oncogenes may be implicated in the pathogenesis and/or the progression of cutaneous T-cell lymphomas. Neither LMP-1 expression nor EBV EBER l/2 transcripts were detected in our series suggesting that EBV is not involved in the pathogenesis of cutaneous T-cell lymphomas.

Herpesvirus 4, Human↗
PubMed1993

Evaluation of the autoimmune response in leprosy.

Immunological responses to a panel of antigens were evaluated in 27 patients with lepromatous and 20 patients with tuberculoid leprosy and compared with 24 pulmonary tuberculosis patients, 25 systemic lupus erythematosus patients and 41 healthy blood donors. Some autoantibody specificities were extensively studied for the first time in mycobacterial infections. Striking immunoserological abnormalities were found in patients with lepromatous leprosy, particularly in those presenting with relapse. Inhibition assays were performed, providing a tool for further analysis of the binding range of specific anti-N.D.O. BSA antibodies and strengthening the suggestion of molecular mimicry reactions between cytoskeletal proteins, host stress proteins and Mycobacterium leprae antigens or stress proteins. A significant serological overlap between lepromatous leprosy and autoimmune diseases is indicated.

Autoantibodies↗
PubMed1993

Thyroid autoantibodies in the subsets of lupus erythematosus: correlation with other autoantibodies and thyroid function.

Thirty four sera from: 12 patients with Systemic Lupus Erythematosus (SLE), 9 with Subacute Cutaneous Lupus Erythematosus (SCLE) and 13 with Discoid Lupus Erythematosus (DLE) (disseminatus 3, localised 10) were tested for the presence of: (a) anti-thyroglobulin and anti-microsomal autoantibodies (b) anti-Sm/RNP, anti-doublestranded. DNA (anti-ds. DNA), anti-single-Stranded. DNA (anti-ss. DNA), anti-cardiolipin (anti-Cl), anti-SSA, anti-SSB, Antinuclear Antibodies (ANA). T3, T4, TSH levels were also determined. Five patients with SLE (41.6%), 4 with SCLE (44.4%), and 2 with DLE (15.3%) had thyroid autoantibodies and only three of the 41 controls (7.3%). Five patients (14.7%), especially from SLE and SCLE groups, had biochemical hypothyroidism whereas only one had hyperthyroidism. Statistical evaluation for the possible coexistence of thyroid autoantibodies with a panel of lupus characteristic autoantibodies, revealed highly significant correlations with anti-Sm/RNP, IgG (p = 0.003) and anti-ds. DNA, IgM (p = 0.012). It may be concluded, that not only SLE but also SCLE predisposes to autoimmune thyroid disease and the prevalence of the latter is related to a great extent to the subset of the LE spectrum. From these results and from the inhibition experiments, it seems that some of the specific mono- or polyclonal autoantibodies may be multiple organ reactive.

Adult↗
PubMed1993

Serum levels of tumor necrosis factor and soluble interleukin 2 receptor as markers of disease activity and prognosis in childhood leukemia and lymphoma.

The serum levels of soluble interleukin 2 receptor (SIL-2R) and tumor necrosis factor (TNF) were assessed in 69 children from 6 months to 14 years old who suffered from acute lymphoblastic leukemia (39), Hodgkin's disease (15), non-Hodgkin's lymphoma (15) and in 54 normal age-matched controls prior to any therapy and at remission. Both SIL-2R and TNF levels were significantly higher at diagnosis compared with normal controls (P < 0.001), but decreased significantly at remission. The SIL-2R and TNF levels were significantly higher in an advanced stage of lymphoma than in an early stage. In the patients with acute lymphoblastic leukemia (ALL) and lymphoma, higher levels of SIL-2R (> 1030 units/ml) and TNF (> 30 pg/ml) were associated with a poorer treatment outcome (P < 0.01). Our findings indicate that elevated TNF serum secretion together with SIL-2R are useful markers in childhood ALL and lymphoma and can be used to assess both disease activity and prognosis in this group of malignancies.

Adolescent↗
PubMed1992

Detection of autoimmunity parameters in the acquired immunodeficiency syndrome (AIDS).

We have examined various autoimmunity parameters in AIDS with special emphasis on the expression of pemphigus and bullous pemphigoid antibodies. Sera from healthy seropositive individuals without syphilis (CS-, n = 17), seropositive individuals with syphilis (cs+, n = 11), and patients with AIDS (n = 6) were studied and compared with normal controls (n = 30); autoimmunity parameters related to dermatology were evaluated. Indirect immunofluorescence (IIF) for pemphigus and pemphigoid antibodies, antinuclear antibodies (ANA), anti-DNA antibodies, antismooth muscle antibodies (ASMA) antimitochondrial antibodies (AMA), and antithyroid antibodies (ATA) was carried out and findings were graded with a cumulative index (CI) for each patient group. Pemphigus and bullous pemphigoid-like antibodies (IgG, PV + BP) were detected in 33% of the AIDS patients. Statistically increased CI (P less than 0.01) was found in the CS- group compared with the CS+ group and in the AIDS group compared with CS- (P less than 0.01).

Acquired Immunodeficiency Syndrome↗
PubMed1991

Towards a better understanding of cellular events in Mycosis fungoides: an immunohistochemical study.

In the present work, we have attempted to pay special attention to epidermal and dermal cellular events in Mycosis fungoides (MF). In the epidermis, the two dendritic cell populations, CD1+ and OKM5+, HLe-1+, the adhesion molecules OKM5 and DR on the surface of epidermal cells (Ecs), and cytoskeletal proteins were studied. CD1+ dendritic epidermal cells were generally more abundant than OKM5+, HLe-1+ ones with no interrelationship in their presence. OKM5+, HLe-1+ dendritic cells prevailed in the second stage plaques. The staining pattern with anti-spectrin polyclonal antibody gradually presented increased intensity from Pre-MF to tumor stage. The activation-proliferation related immunophenotype was also examined, as well as other useful markers, in an attempt to correlate their presence in different stages of MF. Special emphasis was given to the staining pattern with the epidermal growth factor receptor (EGF-R) monoclonal antibody against three targets: epidermal, endothelial, and lymphoid cells. The presence of Ki-67 proliferation marker in suprabasal epidermal layers and lymphoid cells in the dermal infiltrate was also of interest.

Cell Division↗
PubMed1991

Coexistence of pemphigus vulgaris, malignant melanoma and low-grade lymphoma.

A 53-year-old female patient with pemphigus vulgaris under continuous immunosuppressive therapy for about 2 years presented a superficial spreading malignant melanoma on a pre-existing melanocytic naevus. After surgical removal of the inguinal lymph node group, a diffuse low-grade polymorphous immunocytoma was proved both histologically and immunocytochemically. The possible induction mechanisms are discussed.

Female↗
PubMed1989

A five year retrospective study on pemphigus and pemphigoid.

In a five year period 73 cases of pemphigus vulgaris (PV) and 94 of bullous pemphigoid (BP) were studied to investigate important parameters for these diseases. From the results it was found that the incidence of PV was higher in women whereas that of BP was almost equal in both sexes. The incidence of PV was highest in the sixth decade but was highest in the eighth decade for BP. Indirect immunofluorescence (IIF) was more sensitive in PV whereas direct immunofluorescence (DIF) was more sensitive in BP. The present study provides a basis for comparison with results of previous or future studies in Greek and other populations.

Adult↗
PubMed1988

Infiltrate of syphilitic lesions before and after treatment.

An immunohistological study of skin biopsy specimens from patients with early syphilis was undertaken before and after treatment (one day after intramuscular administration of 2.4 MIU benzathine penicillin and eight days later, after a total administration of 3.6 MIU. In chancres from seronegative patients treatment with 3.6 MIU usually resulted in fewer immunocompetent cells in the infiltrate. In lesions of secondary syphilis treatment with 2.4 MIU benzathine penicillin produced a significant decrease in immunocompetent cells. After treatment with 3.6 MIU there was no further decrease. It was worth noticing that even eight to nine days after the initial pretreatment biopsy, when 3.6 MIU had been administered, the overall lymphohistiocytic infiltrate was not substantially diminished. Significantly more suppressor (T8+) cells were found in lesions of primary syphilis than of secondary syphilis, and they showed remarkable exocytosis. Activated local T8+ cells may release immunosuppressive lymphokines.

Dendritic Cells↗
PubMed1988

Vitiligo as a reaction to topical treatment with diphencyprone.

During the topical treatment of 45 patients, who had extensive forms of alopecia areata, with the allergen diphencyprone, 3 of them (6.7%) developed vitiligo. Two were females and 1 male aged 53, 19 and 28 years respectively. None of these patients had a personal or family history of vitiligo. Vitiligo appeared 3-5 months after the onset of treatment and was localized only to the areas of topical application in the younger woman and the man. In the older woman, vitiligo extended to several areas apart from those where the medicament was applied. After the end of diphencyprone treatment, vitiligo had a spontaneous significant improvement only in the man. Mitochondrial autoantibodies were found in the older woman only. To our knowledge, vitiligo due to diphencyprone has not been previously reported.

Administration, Topical↗