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L Brambilla

Publications and source records attributed to L Brambilla.

At least 55 records · Page 3Linked to original sources
PubMed1996

Hydrogen peroxide mediates the killing of U937 tumor cells elicited by pharmacologically attainable concentrations of ascorbic acid: cell death prevention by extracellular catalase or catalase from cocultured erythrocytes or fibroblasts.

Pharmacologically attainable concentrations of ascorbic acid are highly toxic for U937 cells (a human promyelocytic cell line), and this response appears to be mediated by H2O2. This inference finds experimental support in the following observations: 1) toxic levels of H2O2 are readily generated upon dissolution of survival-range concentrations of ascorbic acid in the culture medium; 2) the lethal effects elicited by ascorbic acid or reagent H2O2 are prevented by the addition of either catalase or the intracellular iron chelator o-phenanthroline and are characterized by similar temporal dependence; 3) U937 cells resistant to hydrogen peroxide are cross-resistant to ascorbic acid; 4) under the conditions utilized in this study, H2O2 and ascorbate promote similar modes of cell death (i.e., necrosis); and 5) cell killing provoked by H2O2 or ascorbate is an inverse function of cell density and is suppressed by coculturing U937 target cells with human erythrocytes (at a density far below that present in the blood) and human fibroblasts. Cytoprotection was not observed using catalase-depleted erythrocytes. Taken together, these results strongly suggest that H2O2 is entirely responsible for the ascorbate-induced U937 cell killing. We therefore propose that it is unlikely that the vitamin damages or kills tumor cells of normal tissues in vivo via the H2O2 based mechanism, because the oxidant would be removed promptly by the neighboring cells.

Ascorbic Acid↗
PubMed1995

Effect of a ubiquinone-like molecule on oxidative energy metabolism in rat cortical synaptosomes at different ages.

Persistent stimulation of energy consumption, induced by depolarization with veratridine, mimics a condition of abnormally enhanced energy demand and causes an increase in the oxygen consumption rate (QO2) and in the interconversion of pyruvate dehydrogenase complex (PDHc) into its active form. Wistar rats at the age of 26 months do not show alterations of QO2 and the ability of veratridine to increase QO2 in comparison with 6 month-old animals whereas the active form of PDHc is slightly but significantly reduced. Idebenone, a ubiquinone-like molecule (1 microM), does not affect the QO2 or PDHc activation state in resting conditions but attenuates the veratridine-challenged increase in QO2 at all the ages tested and attenuates the increase in the percentage of PDHa reaching statistical significance in 26-month-old rats. At higher concentration (10 microM) idebenone totally abolishes the veratridine-induced increase in PDHa also in the 6 month-old rats. At the lower concentration, the drug does not affect the increase in QO2 induced by an uncoupler of oxidative phosphorylation. The results obtained suggest a protective effect of idebenone on the cerebral tissue against stressful conditions; this action may be exerted at the level of some mitochondrial component and/or on the Na+ homeostasis.

Adenosine Triphosphate↗
PubMed1994

Mediterranean Kaposi's sarcoma in the elderly. A randomized study of oral etoposide versus vinblastine.

BACKGROUND: This Phase III trial was performed to compare the roles of oral etoposide and intravenous (i.v.) vinblastine in the treatment of Mediterranean Kaposi's Sarcoma (MEKS) in elderly patients with severe disease (Stages II, Ac/B, III, and IV). PATIENTS AND METHODS: Sixty-five patients were randomized to receive either oral etoposide (60 mg/m2 on Days 1-3 during the first course; 60 mg/m2 on Days 1-4 during the second course, and 60 mg/m2 on Days 1-4 during the second course, and 60 mg/m2 on Days 1-5 during the third course; the courses were recycled every 3 weeks) or an i.v. bolus of vinblastine (3 mg/m2 weekly for 3 weeks, and then 6 mg/m2 every 3 weeks). RESULTS: No significant difference between the two drugs was observed in terms of response rates (etoposide, 73.5% vs. vinblastine, 58%; P = 0.3), duration of response, or survival (median not yet reached at a median follow-up of 38 months). Side effects of both treatments were limited, although myelotoxicity was more evident in the vinblastine arm. CONCLUSIONS: Although it is feasible and well tolerated, the oral administration of etoposide at these doses and in this regimen does not appear superior to vinblastine in the treatment of MEKS. Further evaluation of a more intensive schedule in large cooperative clinical trials is needed to establish the role of this drug in comparison with reference treatments.

Administration, Oral↗
PubMed1993

In Saccharomyces cerevisiae, protein secretion into the growth medium depends on environmental factors.

In the budding yeast Saccharomyces cerevisiae the cell wall, mainly composed of mannoproteins and glucans, constitutes a barrier to protein excretion in the growth medium. In this paper we have studied the effects of different environmental parameters on excretion of Escherichia coli beta-galactosidase obtained by exploiting the glucoamylase II signal sequence. Excretion of the unglycosylated beta-galactosidase was detectable only in cells grown in rich medium, was affected by temperature (36 degrees C > 30 degrees C >> 24 degrees C) and slightly stimulated by reducing agents. On the contrary, glycosylated proteins, such as alpha-galactosidase and glucoamylase II, were excreted to a good extent under all tested conditions of medium composition, growth temperature and pH. These data indicate that optimization of environmental parameters may help the excretion of heterologous proteins, offering advantages for protein purification.

Culture Media↗
PubMed1993

Alteration of cell population structure due to cell lysis in Saccharomyces cerevisiae cells overexpressing the GAL4 gene.

Transformed Saccharomyces cerevisiae cells overexpressing the Escherichia coli LacZ gene and the transcriptional activator GAL4, release in the external medium a fraction (from 2 to 10%) of the total beta-galactosidase activity (Porro et al., 1992b). It is known that this abnormal release of a cytoplasmic protein is related to a partial cell lysis of the yeast population, which is likely to be caused by the overexpression of the transcriptional activator GAL4. In the present paper we have characterized the GAL4-induced cell lysis phenomenon. The expression of the GAL4 gene causes morphological modifications and alteration of the cell size distribution. The cell lysis is independent of the expression of the heterologous LacZ gene and occurs in a specific subpopulation of cells (the parent cells) independently of the genealogical age, growth phase conditions and cell cycle progression. Lysis is preceded by a loss of the plasma membrane integrity as indicated by the uptake of ethidium bromide in unfixed cells. Computer analysis of simulated protein distributions indicates that cell lysis takes place in a sizeable aliquot (about 50%) of the parent cells, therefore profoundly altering the age structure of the population.

Cell Fractionation↗
PubMed1993

Multiple miliary osteomas of the face.

We report an exceptional case of multiple miliary osteomas of the face in an elderly woman, which developed in the absence of previous inflammatory or neoplastic skin disease. Excellent aesthetic results were achieved by surgical removal of about 90 miniature stones present in the facial skin of the patient.

Aged↗
PubMed1990

Immunohistological evaluation of basal cell carcinoma immunoinfiltrate during intralesional treatment with alpha 2-interferon.

We investigated the peritumoral and intratumoral immune infiltrate in 6 basal cell carcinomas (BCCs) treated with recombinant alpha 2b-interferon. Each BCC was injected intralesionally three times a week for 3 weeks with 1.5 x 10(6) IU of interferon per injection (total dose 13.5 x 10(6) IU). The immunohistological study was done before the start of interferon therapy and 15 days afterwards, using a series of monoclonal antibodies and an immunocytochemical technique. Before therapy the infiltrate consisted mainly of CD3+ (T) cells, with prevalence of CD4+ (helper/inducer) T cells. The percentage of T cells expressing interleukin-2 receptor (CD25+ cells) was higher in the tumor nests than in the peritumoral infiltrate (20% and 11% respectively). CD1+ (Langerhans) cells and CD14b+ cells (monocytes/macrophages) were present in the peritumoral infiltrate in all cases (9% +/- 5% and 14% +/- 7% respectively). Very few CD56+ (natural killer), CD15+ (granulocytes) and CD20+ (B) cells were observed in the peritumoral infiltrate and none at all in tumor nests. After 15 days of interferon therapy, we observed an increase in peritumoral and intratumoral CD4+ cells. There was a decrease in the number of CD25+ cells and of CD1+ cells in the peritumoral infiltrate. The number of intratumoral CD25+ increased. No variations were seen in CD14b, CD15, CD20, and CD56 positive cells. Eight weeks after completion of therapy, two BCCs were cleared and the remaining four showed clinical and histological improvement. These results may indicate a direct effect of interferon against BCC; in addition the immunohistological findings suggest that intralesional interferon enhances T cell mediated immune response, especially in tumor nests.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

[Structural and ultrastructural study of an isolated case of pili annulati].

A case of pili annulati in an eighteen year old woman is described. The hairs show bright spots along hair shafts when viewed in daylight. The transmission and scanning electron microscopy confirmed that the bright spots are due to small cavities into the cortex. The plasmatic measurement of copper, zinc and of the most important hormone, such as the dosage of plasmatic, urinary and hair aminoacids, allowed the Authors to exclude any influence of metabolic systemic alterations on the pathogenesis of pili annulati. Neither cutaneous nor internal anomalies were detected.

Adolescent↗
PubMed1989

[Late secondary syphilis].

A case of late secondary syphilis characterized by morphologically and topographically typical papulo-nodular and nodulo-ulcerative lesions is described. In the course of the late secondary stage nodular and ulcerous lesions arise as precursors of the tertiary stage. Therapy with penicillin caused the rapid regression of the disease with slight residual atrophy and dyschromia.

Humans↗
PubMed1988

Annular elastolytic giant cell granuloma.

We treated a 13-year-old girl who had annular erythematous lesions with central atrophic areas, which had been present on her trunk and limbs for 4 months. Histological examination revealed patchy dermal lymphohistocytic infiltration with multinucleated giant cells which were phagocytosing elastic fibers, causing them to disappear. The active border of the lesions regressed after intradermal injection of corticosteroids. The classification of the disease and its differential diagnosis from the usual granuloma annulare, inflammatory anetoderma, O'Brien's actinic granuloma, and Convit's disease are discussed.

Adolescent↗
PubMed1988

Oral etoposide for Kaposi's Mediterranean sarcoma.

22 patients affected by locally aggressive or generalized form of Kaposi's Mediterranean sarcoma were treated with oral etoposide (VP16) as single-drug therapeutic regimen. Of the 17 evaluable patients, 10 were pretreated with other chemotherapeutic regimens. VP16 was administered at the dose of 100 mg daily for 3-5 days every 3 weeks for 3 times during induction, then every 4 weeks for 10-12 times during maintenance. Hematological (35.2%) and gastrointestinal (64.7%) toxicities were always mild and swiftly reversible. Good percentages of objective responses were achieved in both nonpretreated (85.6%) and pretreated (70%) patients. The chemotherapeutic regimen employed, the way of drug administration, the results as well as the comparison to another study with vinblastine are discussed.

Administration, Oral↗
PubMed1987

Histological and immunological features of primary Kaposi's sarcoma: evaluation before and after chemotherapy.

Forty-one patients with primary Kaposi's sarcoma (KS) have been evaluated clinically, histologically and immunologically at the time of diagnosis. There was no correlation between histological and immunological features. Moreover, the disease did not appear to be related to particular HLA phenotypes. The T4/T8 ratio was augmented. Leu 7+ cells were also significantly increased. The last 15 patients who received chemotherapy were recently reevaluated after treatment and an increase in B lymphocytes was observed. We also observed that spindle-shaped cells (SSC), which appear later in the histopathological course of the disease, disappear first during chemotherapy, concomitantly with the increase in B cells. We conclude that the course of the disease appears to be controlled by the host's immune response, though there is no clear correlation between histological and immunological evolution. Several immunological features differentiating it from AIDS associated KS have been found.

Aged↗