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Biomedical subjects

G Spagnoli

Publications and source records attributed to G Spagnoli.

At least 37 records · Page 2Linked to original sources
PubMed1994

[Tumor-immune system interaction in renal cell carcinoma and melanomas. Cytokine transcription in tumors at the time of surgical resection].

Tumor infiltrating lymphocytes (TIL) of many tumors express surface activation markers. An antigen driven stimulation of T-lymphocytes is expected to induce not only cell membrane activation molecules but also a unique pattern of cytokine gene transcripts. These cytokines are relevant modulators and potent effectors of immune responses, and therefore play a crucial role in tumor-immune system interaction. The gene transcription of interleukin(IL)-2, IL-4, IL-7, IL-10 and interferon(IFN)-gamma of lymphocyte infiltrated, freshly excised tumor specimens from 10 renal cell carcinomas and 6 melanomas were investigated by reverse polymerase chain reaction (PCR) technique. Autologous, peripheral mononuclear cells (PBMC) and healthy tissue of the affected organs served as controls. In all samples the transcription of the beta-actin gene as a methodological control turned out to be positive. In contrast, no cytokine gene transcription was detected in healthy tissue specimens and PBMC. IL-2 transcripts were detectable in no melanomas but in half of the renal tumor samples. IL-10 never transcribed in melanomas but was positive in 7 out of 10 renal cell carcinomas. In only 2 respectively 1 of the resected tissue probes was transcription of IL-4 and IFN-gamma detected. IL-7 was positive in 1 melanoma and in 6 urological neoplasias. The most impressive fact is the frequent transcription of the inhibiting factor IL-10 in renal cell carcinomas (7/10). This pattern of cytokine gene transcription may explain functional deficits of TIL.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

T-helper- and accessory-cell-independent cytotoxic responses to human tumor cells transfected with a B7 retroviral vector.

As a means to increase the immunogenicity of tumor cells, we have developed a retroviral vector to transfect human B7, a molecule capable of delivering co-stimulatory signals to T cells. Three different tumors, a melanoma, an ovarian carcinoma and a myelomonocytic leukemia, were transfected with high efficiency. When compared for their capacity to stimulate allogeneic T cells, B7+ but not B7- tumor cells were able to stimulate strong proliferative and cytotoxic responses. The effector CTL generated recognised B7+ and B7- cells as well as untransfected tumor cells, indicating that B7 is required in the inductive but not the effector phase of the response. Remarkably, B7+ tumor cells were able to induce cytotoxic responses both by CD4-depleted and by CD8-purified T cells, demonstrating that expression of B7 is at the same time necessary and sufficient to induce a cytotoxic response in the absence of T-helper cells and accessory cells.

Antigen-Presenting Cells↗
PubMed1994

On the suitability of urethane bonds between the carrier and the drug moiety in poly(ethyleneglycol)-based oligomeric prodrugs.

Some poly(ethyleneglycol) derivatives of propranolol were prepared, in which the drug molecule was linked to the oligomeric carrier via urethane bonds in order to study the suitability of this bond as a linkage between the carrier and the drug moiety in oligomeric prodrugs. For comparison purposes also ethanol- and butanol-based prodrugs of propranolol were prepared, with the same linkage between drug and promoiety. The urethane compounds were obtained by condensation via N,N'-carbonyldiimidazole. None of these compounds gave rise to appreciable blood concentrations of propranolol after oral administration, thus suggesting in this particular case, a relative in vivo resistance of urethane bonds towards cleavage.

Administration, Oral↗
PubMed1993

A soluble form of the human CD8 alpha chain expressed in the baculovirus system: biochemical characterization and binding to MHC class I.

We have generated a soluble form of the CD8 molecule consisting of the entire extracellular domains of the human alpha chain, by expressing a mutated CD8 alpha cDNA in SF9 cells infected with a recombinant baculovirus. The truncated molecule was secreted into the medium mostly as a disulfide-linked homodimer in which a single cysteine residue in the hinge-like region (Cys143) was sufficient to assure covalent bonding. Soluble CD8 purified to homogeneity appears to be monodisperse as assessed by gel filtration analysis and contains only O-linked carbohydrates. To determine whether recombinant CD8 can interact with MHC class I molecules, we developed an assay that measures binding of MHC class I-bearing cell lines to purified CD8 adsorbed to plastic plates. The level of binding of cells to immobilized CD8 depended on the amount of CD8 bound to the plate and correlated with the levels of cell surface MHC class I expression. The binding was specifically inhibited by monoclonal antibodies directed either against CD8 or MHC class I molecules. This assay therefore provides a way to measure CD8 binding to MHC class I independently of other cell-cell interactions and should allow direct structure-function studies.

Baculoviridae↗
PubMed1993

CD14 and tolerance to lipopolysaccharide: biochemical and functional analysis.

To evaluate the role of the high-affinity monocyte receptor for lipopolysaccharide (LPS), CD14, in the process of tolerance to LPS, the human monocytic cell line Mono-Mac-6 was cultured in the absence or presence of different amounts of LPS. The kinetics of CD14 modulation in these cells showed an initial 4-day period characterized by increased cell-surface expression, rate of biosynthesis (peaking at 48 hr) and release of its soluble forms (sCD14) which correlated with the amount of LPS in the culture. At this time, tolerance to LPS was already established, as measured by tumour necrosis factor-alpha (TNF-alpha) induction, it was LPS dose dependent and persisted up to 15 days. LPS also reduced the cell proliferation rate in a dose-dependent manner. After 8 days and up to 15 days, the CD14 biosynthesis, cell-surface expression and release of sCD14 inversely correlated with the level of LPS in the culture. The 48-hr LPS-pretreated cells showed a slightly decreased CD14 affinity for LPS, a relative high number of CD14 molecules per cells, and desensitization also to a phorbol 12-myristate 13-acetate (PMA) challenge. An anti-CD14 monoclonal antibody (mAb) protected the cells from tolerization when added at the beginning of culture, as revealed by challenge with LPS and PMA. The data indicate that in this model tolerization to LPS (1) precedes CD14 down-modulation, (2) operates by alteration of the receptor affinity for LPS and by a mechanism which affects a protein kinase C (PKC)-dependent signalling pathway, and (3) that CD14 plays a critical role in the establishment of tolerance to LPS. In addition, analysis of the data suggests the existence of a PKC-independent signalling pathway for LPS tolerization and a CD14-independent mechanism for establishing tolerance.

Antigens, CD↗
PubMed1991

Poly(amidoamine)s with potential as drug carriers: degradation and cellular toxicity.

Poly(amidoamine)s were synthesized by polyaddition reaction: to bis-acryloylpiperazine of piperazine (1), or N,N'-bis(2-hydroxyethyl)ethylenediamine (2), and to 2,2-bis(acrylamido)acetic acid of piperazine (3). Compound 2 was also end-capped with 4-hydroxythiophenol, thus introducing a terminal moiety suitable for radio-iodination using the chloramine T method (4). Such polymers behave as bases in aqueous solution, and their net average charge alters considerably as the pH changes from 7.4 to 5.5. This results in a change in polymer conformation which may prove useful in the design of polymeric drug delivery systems. However, their suitability for use in the organism will depend on polymer toxicity and also on their rate of biodegradation. Here we studied the biological properties of the above poly(amidoamine)s with a view to optimizing the synthesis of novel drug carriers. The general cytotoxicity of compounds 1, 2, 3, and 4 was examined in vitro using two human cell lines, hepatoma (HepG2) and a lymphoblastoid leukaemia (CCRF). Several different methods [the tetrazolium (MTT) test, [3H]leucine or [3H]thymidine incorporation, or counting cell numbers] were used to measure cell viability. Compounds 1, 2, and 4 were much less toxic to both cell lines than equivalent concentrations of the polycationic poly-L-lysine, and in no case did viability fall below 50% (concentrations up to 2 mg/ml). Although compound 2 was not markedly toxic to HepG2 cells, concentration-dependent toxicity was observed against CCRF cells. In this case, the polymer concentration decreasing viability by 59% (ID50) was approximately 50 micrograms/ml for compound 2 compared with an ID50 of approximately 10 micrograms/ml for poly-L-lysine. The rate of hydrolytic degradation of compound 2 was examined using viscometric measurements and gel permeation chromatography (GPC). After incubation at pH 7.5 and 8.0 for 24 h, polymer intrinsic viscosity was decreased by approximately 50% and GPC elution profiles showed a simultaneous increase in polymer retention time, indicating a fall in molecular weight. Hydrolytic degradation progressed much more slowly at pH 5.5. Compound 4 was also incubated with a mixture of isolated rat liver lysosomal enzymes (tritosomes) at pH 5.5, but no increase in the rate of degradation was observed.

Biocompatible Materials↗
PubMed1990

Expression of the human V beta 8 gene product preferentially correlates with class II major histocompatibility complex restriction specificity.

We report that, in peripheral blood T cells, the V beta 8 gene product is much more represented on CD4+CD8- than on CD4-CD8+ lymphocytes. This skewing was observed in all individuals tested and with two independent strategies, one of which allows the selection of V beta 8+ T cells independently from their major histocompatibility complex-antigen specificity. Our data imply that the human V beta 8 gene product confers class II restriction specificity and that both the T cell receptor chains and CD4 molecule are involved in the selection of the T cell repertoire.

Gene Expression↗
PubMed1989

CD3Ti+ human thymocyte-derived clones displaying a differential response to activation via CD3Ti and CD2.

Previous studies indicated that, unlike peripheral T-cells, freshly isolated thymocytes show little or no proliferation to activation signals via either the antigen/MHC receptor complex (CD3Ti) or the CD2 structure, unless exogenous IL-2 or phorbol esters are added. To investigate these differences in more detail, we have studied the response of clonal populations of mature thymocyte subsets as well as peripheral T-cell clones to activation via either CD3Ti or CD2. Here we report the characterization of three clones belonging to different subsets of mature thymocytes: CD3+ CD4+ (Ti alpha/beta), CD3+ CD8+ (Ti alpha/beta), and CD3+ CD4- CD8- (Ti gamma/delta). All three clones could be induced to proliferate to insolubilized anti-CD3 mAb. In contrast, activating anti-CD2 mAbs, which induced proliferation in all peripheral T-cell clones tested, did not induce an appreciable proliferation of the thymocyte clones. The latter required additional signals provided by the phorbol ester PMA. However, anti-CD2 mAbs were able to induce early activation events such as phosphoinositide turnover and [Ca2+]i increase to an extent similar to the ones elicited by anti-CD3 mAb. These results further support previous findings suggesting that mature thymocytes are not functionally identical to peripheral T-cells.

Antibodies, Monoclonal↗
PubMed1987

Molecular cloning and expression of T11 cDNAs reveal a receptor-like structure on human T lymphocytes.

The T11 (CD2) sheep-erythrocyte-binding protein is a T-cell surface molecule involved in activation of T lymphocytes and thymocytes, including those lacking the T3-Ti antigen-receptor complex. The primary structure of T11 was deduced from protein microsequencing and cDNA cloning. The mature human protein appears to be divided into three domains: a hydrophilic 185 amino acid external domain bearing only limited homology to the T-cell surface protein T4 and the immunoglobulin kappa light chain variable region, a 25 amino acid hydrophobic transmembrane segment, and a 126 amino acid cytoplasmic domain rich in prolines and basic residues. Transfection of cDNAs encoding either the 1.7- or the 1.3-kilobase T11 mRNA into COS-1 cells resulted in expression of surface T11 epitopes as well as sheep-erythrocyte-binding capacity. The predicted structure is consistent with the possibility that T11 functions in signal transduction.

Amino Acid Sequence↗
PubMed1983

[Separation of monocytes and their use in a cytotoxicity test].

Observations of acute rejections in uremic patients transplanted with Kidney grafts from Human Leucocyte Antigens (HLA) identical or compatible donors have suggested the importance of the role play by antigens not codified by the Major Histocompatibility Complex (MHC). Some works detected anti-monocytes antibodies that could not be absorbed with platelets (HLA-ABC) or with B lymphocytes (HLA-DR) or granulocytes but only with endothelial cells. Since endothelial cells and monocytes share not HLA surface determinants. Methods to isolate monocytes and endothelial cells have been attempted. We isolated monocytes by Percoll gradients. We checked the purity of our cell population by using monoclonal monocytes. From 30 ml of whole blood we obtained a mean of 50 X 10(6) (min. 12, 6 X 10(6) max 14 X 10(-6] mononuclear cells. After centrifugation of Percoll gradients we recovered a mean 7, 8 X 10(6) cells (Low 1, 3 X 10(6); max. 15 X 10(6] in the monocytes interface. By testing with monoclonal antibodies we found that a mean of 68, 95% (min. 58%; max. 82%) of these cells were living monocytes. We used the cell suspension to detect anti-monocyte antibodies in sera from 171 politransfused uremic patients with long incubation NIH cytotoxicity test.

Antigens, Surface↗
PubMedDate not supplied

Augmentation mammaplasty with a new cohesive gel prosthesis.

We present our experience with augmentation mammaplasty on 14 patients with a thin chest wall and poor subcutaneous tissue. Thanks to Polytech Silimed code 20675, a new anatomical prosthesis filled with "soft" cohesive gel, the lodging in a subglandular position was possible without anomalous salience in the upper pole, and a more natural mammary profile was achieved without capsular contracture, dislocation, or misplacement of the mammary implants.

Adult↗
PubMedDate not supplied

Age increases leucine enkephalin hydrolysis in human plasma.

BACKGROUND: The existence of age-associated alterations in immune functions and neuropeptides capable of modulating these functions prompted us to advance the hypothesis that the degradation of plasma neuropeptides, specifically opioid peptides, may be altered by aging. OBJECTIVE: To verify the possible existence of age-induced variations in neuropeptide hydrolysis in human plasma, using leucine enkephalin as the model substrate. METHODS: The hydrolysis of leucine enkephalin and the formation of its hydrolysis byproducts in the presence of plasma enzymes were studied by kinetic and chromatographic techniques in a group of elderly individuals and a control group. RESULTS: The results obtained indicate that in elderly individuals the activity of enkephalin-degrading plasma enzymes is greater than in controls. ANOVA analysis of these data indicates that the dependency of the variation of hydrolysis upon the 2 age groups is statistically significant. Increased substrate hydrolysis, and a modified hydrolysis pattern, appear to be associated with increased activity of the enzymes involved, and with different distribution of the individual enzymes within each class, as well as with severely reduced activity of the low molecular weight plasma inhibitors. CONCLUSION: The combination of the above-mentioned factors appears to define a characteristic hydrolysis pattern for elderly individuals which is different from that found in controls.

Adult↗
PubMedDate not supplied

A conversational program for hierarchic and non-hierarchic cluster analysis.

The theoretical basis and the features of some cluster analysis programs are described in this paper. These programs use as input data an N x M matrix. For the N' less than or equal to N set of individuals, the cross-correlation matrix, R = (rij), is then calculated. The dissimilarity matrix, D = (dhk), and the distribution histogram of the distances between each pair is worked out. Hierarchic and non-hierarchic clustering techniques are allowed. Using the non-hierarchic strategy, the non-overlapping clusters are then separated into different groups. The distances between these groups are calculated and statistical tests of significance are performed. In the hierarchic case, a dendrogram is drawn using an agglomerative algorithm. As an example the programs (written in FORTRAN, batch or TSS version) were used to classify human mitotic chromosomes.

Classification↗
PubMedDate not supplied

[Biological risk in the operating room: microbiological monitoring of the environment and analysis of the associated variables].

The authors present an environmental microbiological monitoring programme carried out over a period of 15 months in 16 operating theatres performing specific types of surgery. The levels of microbial contamination of the air and of four of the most representative surfaces of the clean area were determined at 3 different times for each theatre, both before and during surgery. For the air assessment, the results obtained with three different samplers, Sed-3 Unit, SAS and RCS, were compared. The results were on the whole acceptable, but some poor conditions were detected during the theatres in use, especially in general surgery theatres; in some of these the floors showed levels of contamination consistently exceeding the reference limits. As the monitoring programme proceeded, the microbiological quality of the air and of the surfaces in the theatres notably improved. The three air samplers showed different conditions expressed with units of measure not always readily comparable. For active samplers, the bacterial load determined by RCS, although less variable, were always higher (even 2-3 fold) than those obtained with the SAS. Passive sampling takes longer but determines the real risk of infection for the patients; contemporary determination of the fall-out and the CFU/m3 helps to identify the occupational risks. Since the limit values established by the ISPESL guidelines for the operating theatres have been defined only for active samplers, there is urgent need for more exhaustive national guidelines to define similar values also for passive sampling. The Authors conclude stressing the importance of promoting continuing information-education programmes to heighten the awareness of all those involved in operating theatre activities.

Air Microbiology↗
PubMedDate not supplied

[Mount Reventino greenstone: assessment of tremolite fibre dispersion in the workplace].

BACKGROUND: Mount Reventino, a massif located in the Calabria Region of Italy, has several ophiolite outcrops of greenstone. These deposits are an important economical resource in the surrounding area. Some rock layers contain tremolite, a type of asbestos fibre. OBJECTIVES: The aim of this paper was to analyze the chemical and physical structure of the outcrops of Mount Reventino, and to assess and reduce the risk to workers associated with exposure to airborne fibres. METHODS: Personal and environmental samples were collected and analysed by Scanning Electron Microscopy equipped with energy-dispersive X-ray analysis. RESULTS: The analysis of samples showed a difference in mineralogical features not only between the quarries under study, but also between the two opposite sides of the mountain. Exploitation of the quarries produces a fibre dispersion that is higher than the natural emission. Occupational exposure to asbestos fibres during greenstone transformation was confirmed by by the results of analysis of the collected samples. CONCLUSIONS: This study made it possible to identify working activities with highest exposure to asbestos and establish the correct procedures to abate fibre dispersion, in order to reduce the correlated risk. Environmental samples collected in the urban area surrounding the quarries showed that the asbestos fibre concentrations were very low, however, further studies are needed in order to confirm these findings.

Air Pollution↗