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Biomedical subjects

F Ricci

Publications and source records attributed to F Ricci.

At least 109 records · Page 6Linked to original sources
PubMed1991

Use of bendazac lysine to limit protein deposition on soft contact lenses in vitro.

We used the heat denaturation of lysozyme to induce the in vitro formation of protein deposits on 60 poly-HEMA contact lenses (38.6% water). Each lens was individually placed in 20 mL of a 0.04% lysozyme solution. The lenses were divided into two equal groups. In the first group (30 lenses), bendazac lysine (100 mg) was added to the lysozyme solution. The second group of lenses was used as control. Quantitative analysis of protein deposits on the lenses of both groups was carried out by a colorimetric test. In the lenses where deposit formation occurred in the presence of bendazac lysine, a mean protein level of 7.17 +/- 3.42 micrograms per lens was found; in the control group the mean value was 30.6 +/- 8.22 micrograms per lens. Student's t-test showed this difference to be significant (P less than 0.001).

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1989

Nucleotide sequence of the gene encoding the nitrogenase iron protein (nifH) of Azospirillum brasilense and identification of a region controlling nifH transcription.

The DNA sequence was determined for the Azospirillum brasilense nifH gene and part of the nifD gene. The nifH gene is 885 bp long and encodes 293 amino acid residues. The region upstream of the nifH open reading frame contains a putative promoter whose sequence shows perfect homology with promoters of other diazotrophic bacteria and two putative upstream activator sequences. Experiments with the promoter-probe vector pAF300 showed that this region promotes transcription in response to the nitrogen and oxygen availability of the cell. The amino acid sequence was deduced from the DNA nucleotide sequence of nifH; the polypeptide contains the four cysteine residues highly conserved among other nifH products and an arginine residue at position 101 which could be the site of the modification occurring during the "switch-off" of nitrogenase. The codon usage appears to be very biased reflecting the high G + C content of the Azospirillum nifH gene. In a comparison of the amino acid sequence with the other 18 known nifH gene products, the A. brasilense nifH product showed the highest level of homology with fast-growing Rhizobia suggesting interesting evolutionary implications.

Amino Acid Sequence↗
PubMed1989

A national voice for information about HIV infections: the Italian state AIDS hot-line.

Because of the variety of problems connected with the AIDS epidemic, there is an urgent need for qualified information and counselling. In June 1987, The Italian Ministry of Health established a hot-line, acting within the National AIDS Operational Centre. Through the analysis of more than 39,000 calls received during the first year of activity, a clear outline has been obtained of the emotional impact of the disease on Italian public opinion, and of the problems raised. 67% of callers belong to 20-39 age group; the male/female ratio is 2:1. Interesting correlations have been found between the content of the questions and the sex, age, and type of caller. The vast majority of questions concerning basic concepts and notions about HIV infections are asked by no-risk-related subjects. During the first year, the percentage of questions asked by subjects actually at risk increased, and the questions themselves have become more specific.

Adult↗
PubMed1989

Immunochemotherapy of advanced colorectal cancer with alpha-interferon and 5-fluorouracil. 1. Toxicological studies.

Twelve patients with advanced colorectal cancer were subjected to alternating cycles of treatment with low immunomodulating doses of recombinant alpha-interferon (alpha IFN) + 5-fluorouracil (5FU) or with 5FU alone. Hematological, biochemical and physical evaluation of the patients showed that alpha IFN + 5FU cycles were well tolerated like 5FU alone, except for modest and transient fever following alpha IFN administration. At hematological nadir (day 15-18 of each cycle) lymphocytopenia and granulocytopenia were more pronounced during alpha IFN + 5FU than 5FU cycles. No difference was found for platelet nadir. At the beginning of each cycle complete leukocyte recovery was observed in all cases. Platelet recovery was also complete, although counts were higher after alpha IFN + 5FU than after 5FU alone. Clinical results showed 1 complete remission, 1 partial remission, 5 stable disease and 5 progressive disease. These data point out that low doses of alpha IFN can be safely associated with 5FU. However further studies are required to establish the possible therapeutic value of alpha IFN-mediated immunomodulation for immunochemotherapy of colorectal cancer.

Adult↗
PubMed1989

Isolation and characterization of Saccharomyces cerevisiae mutants resistant to sulphite.

Several spontaneous and UV-induced sulphite resistant mutants of Saccharomyces cerevisiae have been isolated and characterized. Some of the UV-induced mutants appeared to be much more resistant than the spontaneous ones, as judged by their plating efficiency and cellular growth in the presence of increasing concentrations of sulphite. All the resistant mutants seemed to have an intracellular glutathione content and glutathione reductase activity higher than and an extracellular glutathione concentration lower than the parental strain.

Culture Media↗
PubMed1988

Combined effects of host antitumor immune responses and chemotherapy. Studies with hexamethylmelamine.

The antitumor activity of hexamethylmelamine (HMM) was tested in various mouse tumor models in the presence or absence of host-vs-tumor graft responses. The drug was moderately active against Sarcoma-180 growing in different strains of non-sensitized mice. Strong protection was afforded when recipients were preimmunized with irradiated tumor cells 15 days before tumor challenge followed by HMM treatment. The drug did not show antitumor activity against two radiation-induced lymphomas of congenic mice of B10 background, inoculated into H-2 compatible hosts, or into mice incompatible for subregions of H-2. In this model HMM increased mortality of allogeneic mice presumably through impairment of host-vs-lymphoma graft resistance. In conclusion this study shows that synergistic or antagonistic effects can be obtained by combining chemotherapy with antitumor immune responses.

Altretamine↗
PubMed1987

A study on the incidence of postoperative infections and surgical sepsis in a university hospital.

Reported are the results of a study on the incidence of nosocomial surgical infections in ten wards of the university hospital A. Gemelli, Rome. One thousand, five hundred five patients were studied and the overall incidence of surgical infections was 8.7%. Factors that influenced infection rates included age, immunosuppressive diseases, and immunosuppressive therapy. We assessed the inutility of antibiotic prophylaxis in clean operations and its usefulness in clean operations with insertion of prostheses or other devices. The importance of the duration of preoperative hospitalization and of the length of the operation were also noted. The most frequent etiological agents proved to be Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. The average hospital stay for patients with surgical infection was more than double that of patients with no infection (25.7 days v 11.7 days).

Age Factors↗
PubMed1987

Combined effects of immunity and antitumor drugs against cancer. II. In vitro studies with cis-diamminedichloroplatinum in a human leukemia system.

Human K562 leukemic cells were exposed in vitro to cis-diamminedichloroplatinum (DDP) followed by addition of intact or irradiated mononuclear cells (MNC) obtained from peripheral blood of normal donors. tumor inhibition provoked by DDP was significantly enhanced by normal MNC, but not by irradiated cells at the effector: leukemic cell ratio of 2:1. In contrast MNC alone did not show appreciable effects on K562 cells. The NK activity of MNC was also inhibited by exposure to gamma rays. The combined effects of DDP + MNC do not appear to be due to increased susceptibility of DDP-pretreated K562 cells to NK-mediated cytolysis. Actually leukemic cells treated with 10 micrograms/ml of DDP and cultured for 48 h at 37 degrees C, showed decline of susceptibility to the cytotoxic effects of MNC. These studies suggest that natural immunity could be of potential value in the clinical use of DDP.

Cell Division↗
PubMed1987

Clearance of maltose administered at different infusion rates.

Maltose is a disaccharide consisting of 2 molecules of d-glucose which at 10% solution is isotonic with plasma but provides a caloric supply double than glucose. Its possible use in total parenteral nutrition was investigated. Two homogeneous groups of patients were infused during a 2-hour period with a 10% maltose solution at 0.2 g/kg/h and at 0.4 g/kg/h flow rate. The data collected during and at the end of infusion demonstrate that: 1) the major metabolic parameters do not undergo significant alterations after maltose infusion; 2) the infusion at 0.4/kg/h causes an osmotic diuresis that does not significantly affect the water-electrolyte balance of the patients. Nevertheless it is not possible to exclude that this condition may lead to negative side-effects in critical patients; 3) the urinary excretion of maltose and glucose is significantly higher in the group of patients with 0.4 g/kg/h infusion rate.

Blood Glucose↗
PubMed1987

HLA-DR antigens on colonic epithelial cells in inflammatory bowel disease: I. Relation to the state of activation of lamina propria lymphocytes and to the epithelial expression of other surface markers.

The colonic epithelial expression of HLA-DR molecules and of other markers of cell membrane perturbation was investigated by immunofluorescence in biopsy specimens from patients with ulcerative colitis and Crohn's disease. It was found that in virtually all specimens from either groups showing active inflammation there was a diffuse epithelial expression of HLA-DR molecules. There was no relation between the grading of active inflammation and the epithelial expression of HLA-DR antigens. The epithelium of virtually all specimens from the macro and microscopically uninvolved areas of patients with active colitis and from patients with histologically quiescent colitis showed no detectable expression of HLA-DR molecules. The counts of isolated lamina propria lymphocytes expressing the transferrin receptor and the interleukin 2 receptor were higher in specimens with HLA-DR+ epithelium than in those with a HLA-DR- epithelium. Twenty-nine of the 35 (83%) HLA-DR positive specimens proved to express the 4F2 antigen on their epithelium and 19 (54%) were positive for the transferrin receptor. All sections positive for either the 4F2 antigen or the transferrin receptor were also HLA-DR positive while all HLA-DR negative sections were also negative for either of the two other markers. Data in this study suggest that in active IBD the epithelial participation in active inflammation is associated with a sequence of cell membrane rearrangements, and that the expression of HLA-DR molecules is a part of this sequence.

Antigens, Surface↗
PubMed1987

Combined effects of immunity and antitumor drugs against cancer. I. In vivo studies with cis-diamminedichloroplatinum and cyclophosphamide in mouse models.

Cis-diamminedichloroplatinum (DDP) or cyclophosphamide (Cy) were given to mice bearing L1210 or LSTRA leukemia in H-2 compatible tumor-host combinations. Little anti-tumor activity was afforded by DDP against both leukemias inoculated in entirely histocompatible recipients. However, when the drug was given to mice incompatible for minor histocompatibility loci (MMHL) with the tumor, the efficacy of the treatment was markedly augmented and a substantial number of long-term survivors was found among BALB/c mice inoculated with L1210 cells. On the other hand, no difference in survival times was found between histocompatible or allogeneic mice inoculated with both leukemias, not subjected to chemotherapy. The LSTRA model was much less susceptible to this type of DDP-mediated antineoplastic immuno-chemotherapy synergism. Moreover no synergistic effects with allograft reaction were detected with Cy in both L1210 and LSTRA models, although Cy was markedly more active than DDP against leukemic cells in histocompatible recipients.

Animals↗
PubMed1986

Oscillatory singular integrals and harmonic analysis on nilpotent groups.

Several related classes of operators on nilpotent Lie groups are considered. These operators involve the following features: (i) oscillatory factors that are exponentials of imaginary polynomials, (ii) convolutions with singular kernels supported on lower-dimensional submanifolds, (iii) validity in the general context not requiring the existence of dilations that are automorphisms.

Journal Article↗
PubMed1986

[In vivo study in healthy volunteers on the effect of tetracycline and cotrimoxazole on chemiluminescence and granulocyte adhesion].

The influence of tetracycline and cotrimoxazole on polymorphonuclear leukocyte (PMNL) chemiluminescence and adherence to nylon was investigated in vivo on healthy volunteers. A significant impairment of chemiluminescence and (although not statistically significant) an inhibitory effect on adherence to nylon was observed in subjects receiving tetracycline. Cotrimoxazole did not appear to have a significant influence on PMNL function.

Adult↗