Biomedical subjects
Publications and source records attributed to L Ventura.
The Aspergillus terreus gla1 gene, coding for a glucoamylase, has been cloned by heterologous hybridization. The gene is interrupted by four introns and encodes a protein with an N-terminal catalytic domain and a C-terminal starch-binding domain. The expression of the gene is induced by starch and maltose and repressed by glucose.
Population dynamics of natural and inoculated industrial wine fermentations have been studied by using a simple molecular biology technique based on mitochondrial DNA restriction analysis profile. The predominance of the inoculated strain in the inoculated fermentations is obvious. A genetic transformation system has been developed for an industrial wine yeast strain named T73. By using this technique, different fungal hydrolases in this industrial strain have been expressed. Problems and benefits of the application of recombinant DNA techniques in wine yeast strains are also discussed here.
Human papilloma virus (HPV) may have an important role in oral carcinoma etiology. Our work compares the presence of HPV in the epithelium of oral mucosa of patients with oral carcinoma with other factors of risk (smoking, alcohol, chronic mucosal trauma). We studied 33 patients operated for oral cancer at St. Salvatore Hospital in l'Aquila, in January-December 1990. The presence of HPV was proved by a direct valuation of morphological signs (coilocytosis, nuclear inclusions, etc.) and by immunohistochemical technique with primary antibodies against structural virus antigens. Among the 33 patients 19 (57.6%) were positive for HPV and 14 (42.4%) were negative. Among the HPV positive subjects 13 were smokers, 11 usually assumed alcohol and 6 had chronic mucosal trauma. Among the HPV negative subjects 9 were smokers, 7 assumed alcohol and 3 had chronic mucosal trauma. The statistical evaluation of data showed the lack of significance of viral infection compared to other factors of risk. In spite of a few cases examined, we suppose that HPV doesn't play a primary role in oral cancerogenesis, but is a concomitant cause with other factors of risk.
The effects of macrophage colony-stimulating factor (M-CSF) on CD4 receptor expression, susceptibility to human immunodeficiency virus type 1 (HIV) infection, and anti-HIV activity of dextran sulfate and soluble-CD4 were studied in cultured, human primary macrophages. M-CSF stimulated macrophage cells to express the CD4 receptor, and this resulted in an increase of both the number of CD4+ cells and the density of the receptor on the cell surface. M-CSF also significantly enhanced the susceptibility of macrophage cells to HIV infection. Interestingly, the anti-HIV activity of dextran sulfate and soluble-CD4 (two compounds that interfere with HIV-CD4 binding with different mechanisms) was reduced 100-fold and fivefold, respectively, in M-CSF-treated macrophages. Human blood concentrations of M-CSF are reported to be similar to those used in this work (1,000 U/mL); thus, it is conceivable that also in vivo this cytokine may modify the susceptibility of macrophages to HIV and the ability of dextran sulfate and soluble CD4 to inhibit HIV replication. These results suggest that the in vitro study in M-CSF-treated macrophages of promising drugs inhibitors of HIV-CD4 binding could provide further insights into the potential efficacy of these compounds in patients.
Explore the source record for details and available documents.
AIMS AND BACKGROUND: Gastric cancer (GC) represents one of the most important causes of death by malignancy world wide. Our retrospective study was carried out on surgical stomach specimens obtained from a series of 552 consecutive cases of GC observed in the Departments of Surgical Pathology of the Public Hospitals of L'Aquila and Atri which cover the 17% of the entire population of the Italian Region Abruzzo. The aim of the study was to compare the anatomo-clinical characteristics of early GC (EGC) and advanced GC (AGC). METHODS: The diagnosis was achieved by the criteria of the Lauren's histopathological classification (intestinal and diffuse types). Our study also stratified the cases by sex, age, lymph node metastases and associated lesions such as chronic atrophic gastritis, intestinal metaplasia and dysplasia. RESULTS: On an average, patients affected by EGC were 8.1 years younger than those with AGC. This age gap could support the hypothesis that early lesions represent the first stage of AGC. However, when patients were subdivided according to Lauren's classification, the mean age of patients with EGC, diffuse type, was 12.2 years less than that of AGC patients of the corresponding histological type. Furthermore, the subset of patients with EGC, diffuse type, and lymph node metastases was 17.8 years younger than patients affected by AGC diffuse type, with lymph node metastases. CONCLUSIONS: The present study offers an original survey on GC in a defined Italian population. As far as the intestinal histotype is concerned, the slight age difference between EGC and AGC suggests that these tumors are different steps of the same process. On the contrary, the age distribution suggests that EGC, diffuse type, has a different biological behaviour.
Food industries use a great variety of enzymes as additives. The main percentage of them are produced by species of filamentous fungi. In this review we present the strategies to purify and overproduce this kind of enzymes using recombinant DNA techniques.
Using filtration enrichment techniques, an Aspergillus terreus arginine auxotrophic strain which contains a mutation that abolishes ornithine transcarbamylase (OTCase) activity has been isolated. This mutant has been genetically transformed with the cloned Aspergillus nidulans OTCase gene. Prototrophic transformants arose at a frequency of about 50 transformants per microgram of plasmid DNA. Southern blot analysis of DNA from the transformants showed that the transforming DNA was ectopically integrated at different locations in the A. terreus genome, often in multiple tandem copies. The transformants were phenotypically stable for several mitotic divisions and retained their capacity to produce extracellular enzymes.
A method for assessing the effect of clastogens on mouse skin epidermal cells was devised and applied. Toxic and mutagenic responses in epidermal cells were tested using two known mutagens and carcinogens, urethane (URE) and 7,12-dimethylbenz[a]anthracene (DMBA). Cell generation time, sister-chromatid exchanges (SCE) and chromosomal aberrations (CA) after topical and intraperitoneal (i.p.) treatment were measured in epidermal and bone marrow cells. After topical administration both tissues responded similarly, whereas after i.p. treatment skin cells were less responsive than bone marrow cells. However, the results indicate the validity of this new cytogenetic approach for the assessment of the genotoxicity of compounds applied directly to skin.
The mechanism of ornithine decarboxylase (ODC) induction by phorbol ester (TPA) has been studied in two permanent epithelial cell lines, a control (Ctr) and a Benzo (a) pyrene transformed line (BaP-tr); the degree of ODC gene expression (ODC-mRNA) was evaluated in comparison to the ODC activity. A small dose of TPA (4 x 10(-8) M) highly induced ODC activity in these cells. The induction levels differed however, corresponding respectively to 4:1 (induced: basal ODC) in Ctr cells and to 2:1 in BaP-tr cells. This difference reflected the variation of ODC gene expression; the ODC-mRNA induction was 6:1 in Ctr cells and 3:1 in BaP-tr cells. Repetitive TPA treatment decreased the ODC induction in these cells, as compared to that resulting from a single TPA treatment. Studies of ODC modulation were performed in presence of anti-inflammatory agents. In the two cell lines, Indomethacin (anti-cyclooxygenase) did not change the level of ODC induction by TPA. Nordihydroguaiaretic acid (NDGA, anti-lipoxygenase) inhibited this induced ODC. These results differed from that obtained in vivo in mouse skin. Dexamethasone (DXME, anti-phospholipase A2) showed different action according to treatment time. Used together with TPA (t0), DXME inhibited ODC induction by the carcinogen; with three hours delay after TPA (t3), DXME treatment stimulated ODC in the cells. This divergent action may be reproduced by Actinomycin D, while Cycloheximide only exhibited constant inhibition. Studies now in progress suggested that the inhibition of TPA induced ODC by DXME may reflect ODC gene repression, as for the stimulating effect it could be related to ODC post-transcriptional modulation, owing to the decrease of proteolytic action.
Aspergillus terreus was transformed to hygromycin B resistance using a bacterial resistance gene under the control of Aspergillus nidulans regulatory sequences. Southern hybridization of transformants indicated that in most of the cases the vector DNA was integrated into the recipient chromosome in the form of tandem arrays. Transformants were mitotically stable in both selective and non-selective medium and retained their capacity to produce xylanase or glucoamylase activities.
Trenbolone, a synthetic androgen together with testosterone, a natural androgen, were studied comparatively for their transforming effects on Syrian hamster embryo (SHE) cells. The data indicated that both androgens exhibited weak positive complete transforming activities without a dose response relationship. Trenbolone is more toxic than testosterone when the concentrations tested are higher than 10 micrograms/ml, but is less able to transform SHE cells. Medium H21 offers a higher transformation frequency than medium H16. Their transforming effect can be amplified by TPA. However, both products can also reduce the transforming effect of benzo[a]pyrene (B[a]P) either in sequential treatment or when mixed together. The transforming effects of the two androgens including TPA effects can be inhibited completely by dexamethasone, which suggests that such transformation in SHE cells is an epigenetic effect. In conclusion, trenbolone and testosterone themselves exhibit a weak transforming effect on SHE cells, predominantly as promoting potential, especially when associated with 12-O-tetradecanoyl-phorbol-13-acetate, which is related to hormonal action. They also exhibit weak anti-transforming effects when associated with B[a]P.
The induction of micronuclei and nuclear anomalies in cells of the gastro-intestinal epithelium of rats treated per os with formaldehyde (200 mg/kg) was assessed in comparison with N-methyl-N'-nitro-N-nitrosoguanidine as a positive standard. Formaldehyde and N-methyl-N'-nitro-N-nitrosoguanidine both increased micronuclei and nuclear anomalies in almost all tissues analysed (stomach, duodenum, ileum and colon) though with different patterns and to different extents, reflecting different potency and specificity of target. In the case of formaldehyde these effects were observed in conjunction with signs of severe local irritation. This assay can be employed to detect the genotoxic potential of chemicals in vivo directly on target cells in the proximity of the administration site, thus reducing the likelihood of false-negative results.
Incontinentia pigmenti (IP) is a genodermatosis, which is of X-linked dominant transmission, uncommonly diagnosed in newborn babies. The skin lesions usually develop in 4 stages: inflammatory, hypertrophic, pigmentary and regressive. The authors report 2 cases of IP in female newborn babies who were previously treated for pyodermatitis.
The potential proliferative activity of glial tumors has been investigate by serial stereotactic biopsies and by "in vitro" 3H-thymidine incorporation procedure (labeling index, LI). The methodology of this combined approach and the preliminary results in 33 patients are reported. Cell kinetic data have been matched with the histological classification (W.H.O.).
The relevance of tumor proliferative activity as an indicator of biologic aggressiveness was analyzed on a series of 506 patients with primary breast cancer. In 258 patients with operable tumors without nodal and distant metastases, none of whom was subjected to postoperative irradiation or systemic adjuvant therapy, proliferative activity was significantly correlated with prognosis; 6-year relapse-free survival (RFS) and overall survival (OS) were higher for patients with slowly proliferating tumors for patient with fast-proliferating tumors (RFS: 80.5% vs 59.6%, p = 0.00004; OS: 90.8% vs 74.4%, p = 0.002). On a series of 196 patients with node-positive operable tumors, subjected to 6 or 12 cycles of cyclophosphamide, methotrexate and 5-fluorouracil, a trend in favor of longer 6-year RFS was observed for patients with slowly proliferating tumors than for patients with fast-proliferating tumors (62.5% vs 48.3%, p = 0.08), whereas proliferative activity did not influence OS. In 52 patients with locally advanced disease treated with a multimodality approach, including chemotherapy (adriamycin and vincristine), surgery or radiotherapy, tumor proliferative activity was a strong indicator of biologic aggressivity, since women with slowly proliferating cancers had a higher 4-year probability of OS than women with fast-proliferating tumors (68.1% vs 36.7%, p = 0.02).
Serum alkaline phosphatase (ALP EC 3.13.1) isoenzyme patterns were studied in 110 patients with hepatobiliary disease in order to evaluate whether the appearance of the fast liver fraction, absent in normal subjects, could be a marker of cholestatic mechanism. This possibility was studied even when the ALP values are borderline or within normal limits. In conclusion it was found that the fast liver fraction, absent in normal subjects, can satisfactorily discriminate between cholestatic and non-cholestatic disease. Statistical analysis has shown a sensitivity of 98%, a specificity of 92%, a predictable positive value of 90%, a predictable negative value of 98% and a validity of 95%. False positive are 10% and false negative 2%; chi 2 test was 45.008, p less than 0.001. The results show that the presence of this fraction, besides being highly specific, is also an early marker for cholestasis.
The use of an iridium microelectrode 0.5 mm in diameter is proposed for measuring the pH gradient in polyacrylamide gels after isoelectric focusing. The electrode exhibits a perfectly linear potential/pH relationship; thus it can be used directly in conjunction with a pH meter using the pH scale for readings. pH equilibrium values are rapidly reached (10-15 s) and pI determinations are obtainable with good accuracy (better than 0.1 pH).