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Biomedical subjects

S Villa

Publications and source records attributed to S Villa.

At least 55 records · Page 3Linked to original sources
PubMed1992

IHP entrapment into human erythrocytes: comparison between hypotonic dialysis and DMSO osmotic pulse.

Three different blood units were treated separately by the hypotonic dialysis (HD) and the dimethylsulphoxide osmotic pulse (DMSO) method, in order to load the erythrocytes with inositol hexaphosphate. A detailed comparison between the two loading techniques was performed by monitoring the red cell distribution patterns on discontinuous Percoll density gradients, the RBC oxygen affinity and the amount of the main intracellular organic phosphates with the 31P-NMR. The results obtained showed that: (1) The HD loading produces a redistribution of the RBC fractions with a concomitant smoothing of the relative differences among distinct fractions (2) only a minor portion of erythrocytes (from 8.5 to 24.9% of total RBCs) are loaded with IHP after the DMSO treatment. All of these cells move to the lightest fraction (d = 1.080 g/ml). (3) Both HD and DMSO IHP-loaded cells show an increase in P50 (basal vs. after loading, means +/- SD: 25.8 +/- 3.0 vs. 52.5 +/- 3.2 mm Hg) correlated to the IHP incorporation (mean intracellular IHP concentration: 4.2 mmol/l RBC). (4) probably the IHP incorporation efficiency could be probably improved at least by increasing the IHP concentration during the treatment.

Dialysis↗
PubMed1992

[Radiotherapy in the control of bone metastases in patients with adenocarcinoma of the prostate].

Advanced prostatic carcinoma shows a high incidence of bone metastases. This is the main cause of clinical problems such as invalidating bone fractions, collapses and consequently of sharp pain syndromes. In these cases the therapy needs to achieve quick relief of symptoms. Radiotherapy, with its large variety of technical options, allows a wide modulation to fit a lot of clinical situations among the most frequent for these patients. A large series of treatment modalities and related indications will be presented and discussed in this work.

Adenocarcinoma↗
PubMed1990

Plasma neurotransmitters and cortisol in duodenal ulcer patients. Role of stress.

Levels of noradrenaline, adrenaline, dopamine, free serotonin, platelet serotonin, and cortisol were measured in the plasma of duodenal ulcer patients and controls. All subjects received antacids, and these substances were also measured. During relapse, all patients showed raised noradrenaline, adrenaline, dopamine, free serotonin, and cortisol values. In contrast, platelet serotonin showed very low values, which correlated negatively with all the former, except free serotonin. No correlations were found in parameters of the controls. After healing, significant reductions of noradrenaline, adrenaline, dopamine, free serotonin, and cortisol and significant increases of platelet serotonin values were observed. However, only dopamine, free serotonin, and cortisol reached normal values. Noradrenaline and adrenaline remained higher and platelet serotonin lower, both significantly more so than normals. These still-altered parameters showed similar correlations to those found during relapses. The present results demonstrate that some baseline autonomic system imbalance exists in patients, amplified and accentuated during relapse. We discuss the possibility that stress plays some role in triggering duodenal ulcer relapse.

Adult↗
PubMed1989

Cyanogen bromide cleavage at methionine residues of polypeptides containing disulfide bonds.

A method for cleaving polypeptides at their methionine residues without affecting intramolecular disulfide bonds is described. This method may be applied for cleaving recombinant heterologous hybrid polypeptides with release of the interesting peptide. The method may also be applied to assign the correct positions of disulfide bonds in protein molecules.

Chromatography, High Pressure Liquid↗
PubMed1989

Pimozide therapy for trigeminal neuralgia.

Pimozide was compared with carbamazepine in a double-blind crossover trial in 48 patients with trigeminal neuralgia who were refractory to medical therapy. Pimozide treatment produced greater reduction in trigeminal neuralgia symptoms than carbamazepine treatment. All of the pimozide-treated patients improved, while only 56% of carbamazepine-treated patients were relieved of their pain. Although both drugs provoked some adverse effects, it was not necessary to interrupt the trial in any case. After this 24-week trial, all patients began receiving pimozide and were followed up according to an open-label study design. In all cases, the pimozide dosage was progressively reduced until the minimal effective dose was reached. Central and peripheral mechanisms that may underlie pimozide-induced improvement are discussed.

Carbamazepine↗
PubMed1989

Body iron status in critically ill patients: significance of serum ferritin.

Serial measurements of blood haemoglobin, serum iron, serum transferrin, total iron-binding capacity, transferrin per cent saturation and serum ferritin were determined in 51 post-operative critically ill patients to investigate body iron status in severely stressed patients. The results showed decreased blood haemoglobin, serum iron, serum transferrin and transferrin saturation compared to an increase in serum ferritin levels. These results indicate that there is inadequate availability of iron to tissues (secondary to rearrangement of body iron to the advantage of the iron storage compartment), which is often present in severely critically ill patients. A positive correlation was found between the initial (ferritin) levels and SAPS (r = 0.41, p less than 0.01). In addition, the increase of ferritin concentration parallels a worsening of the clinical status in severely ill patients. This is due to enhanced release by the macrophage system. From this, we consider serum ferritin as an acute-phase protein and a useful marker of the severity of the clinical status. It appears to be useful in predicting the patient's outcome, but is not reliable in evaluating iron stores in stressed patients.

Adolescent↗
PubMed1988

Cisplatin (P) versus cyclophosphamide, adriamycin and cisplatin (CAP) for stage III-IV epithelial ovarian carcinoma: a prospective randomized trial.

In 1982 a randomized trial was started to compare a cisplatin-containing polychemotherapy (CAP: cyclophosphamide - CPA 750 mg/m2, adriamycin - ADM 50 mg/m2, cisplatin - P 50 mg/m2 on day 1 every 21 days) with full-dose cisplatin as single agent (P 60 mg/m2/day on days 1 and 2 every 28 days) in 44 patients undergoing exploratory laparotomy or debulking surgery for stage III-IV epithelial ovarian carcinoma with residual disease greater than 5 cm. The response was evaluated at second-look surgery with random biopsies and peritoneal washing. On the basis of the final results the authors underline some data which, although merely indicative (because of the small number of patients) appear to be worth considering since they are in accordance with the latest reports: a) similar response rate (CR + PR = 47%) to first-line treatment in the two groups; b) the CAP treatment may achieve a longer median duration of CRs than the P treatment (20 versus 11 months); c) overall survival seems similar in the two groups of patients (19 versus 18 months), whereas the survival of CRs seems longer in the CAP treated patients (greater than 32 versus 25 months). The authors also discuss some observations on a possible salvage therapy.

Adult↗
PubMed1988

Activity of a monoclonal antibody-saporin-6 conjugate against B-lymphoma cells.

A monoclonal antibody reactive with the immunoglobulin heavy chain (TEC IgM) has been conjugated to saporin-6 (SAP), which is the major ribosome-inactivating protein from the seeds of the plant Saponaria officinalis. Studies with Burkitt's lymphoma cell line Bjab 113 demonstrate that this immunotoxin is capable of killing 3 logs (99.9%) of clonogenic lymphoma cells after a 2-hour incubation. The presence of human bone marrow inhibits the activity of the conjugate. However, full potency of TEC IgM-SAP immunotoxin is restored by adding 1 mM amantadine to the incubation medium. The reaction is highly specific and is inhibited by the presence of excess anti-mu-antibody or human serum. Clonal growth of other Burkitt's lymphoma cell lines is inhibited to a lesser extent by the immunotoxin. The presence of surface IgM on the different cell lines is directly correlated to target cell killing by TEC IgM-SAP. Isolation of Bjab 113 clones surviving treatment demonstrates that only a minority are truly resistant and that the others randomly escape the treatment. The highly potent and specific activity of this conjugate in the presence of bone marrow buffy coat and its exceptionally rapid onset of action make this conjugate a good candidate for the ex vivo elimination of neoplastic cells from the bone marrow of non-Hodgkin's lymphoma patients.

Antibodies, Monoclonal↗
PubMed1988

Expression in Escherichia coli and characterization of human growth-hormone-releasing factor.

A chemically synthesized DNA sequence, coding for the 44 amino acid residues of human growth-hormone-releasing factor (GRF) preceded by a tryptophan codon, was cloned in frame with Escherichia coli trpE gene within a pBR322-derived plasmid. GRF was expressed in E. coli as a fused polypeptide chain (TrpE-GRF) and then the GRF amino acid sequence was released from the fused protein by specific chemical cleavage at the tryptophan residue using o-iodosobenzoic acid. The thioether group of the methionine residue of GRF was converted in the sulfonium salt derivative, in order to prevent irreversible oxidation of methionine to the sulfone derivative by the o-iodosobenzoic acid reagent. GRF was purified by HPLC and characterized in terms of amino acid composition after acid hydrolysis, protein sequencing and gel electrophoretic behaviour. These data clearly established that the biosynthetic GRF was identical to the natural one, except for the lack of amidation at the carboxyl-terminal amino acid. Far-ultraviolet circular dichroism measurements established that both biosynthetic and natural GRF are devoid of secondary structure in aqueous solution at neutral pH, whereas both peptide samples achieve a high percentage of helical structure in the presence of trifluoroethanol.

Chromatography, High Pressure Liquid↗
PubMed1988

Analysis of leukocyte antigens detected by immunoenzymatic staining on human bone marrow colonies.

Immunoenzymatic (IE) staining for antigen detection on intact human bone marrow (BM) colonies grown in agar layers is described. The reliability of this method allowed a study of antigenic changes during myelomonocytic differentiation. Phenotypic analysis was carried out at different times using the following monoclonal antibodies (MoAbs): S16.144, R1B19, UJ308, TG1 (CD 15), and UCHM1 (CD 14). The results confirmed that the clonogenic assay for human BM cells allows the detection of two granulo-macrophagic colony-forming cells (GM-CFC) appearing at different times during culture. In addition, this study pointed to a temporal sequence in the appearance of the markers analyzed: UJ308 seems the earliest detectable marker followed by R1B19, TG1, UCHM1, and S16.144, respectively. These findings suggest that the granulocytic differentiation occurs earlier than that of monocytes and that UJ308 is probably present on a subpopulation of myeloid cells expanded during hemopoietic regeneration.

Antigens, Differentiation↗
PubMed1988

Synthesis and characterization of an antihuman T-lymphocyte saporin immunotoxin (OKT1-SAP) with in vivo stability into nonhuman primates.

The authors conjugated, by a disulphide bond, the antihuman T-lymphocyte (CD5) monoclonal antibody (MoAb) OKT1 to the saporin-6 (SAP) ribosome-inactivating protein of the plant Saponaria officinalis. The resulting OKT1-SAP immunotoxin bound to CD5-expressing target cells and under standard culture conditions specifically suppressed mitogen-induced-T-lymphocyte DNA and protein synthesis in a dose-related manner. T-lymphocyte killing was achieved by five-minute exposure of the target cells to OKT1-SAP. The concentration inhibiting 50% (IC50) of T-lymphocyte DNA synthesis was 0.32 nmol/L. The potency of OKT1-SAP was moderately enhanced by amantadine (IC50 0.08 nmol/L) but not by ammonium chloride or chloroquine. Whole blood components did not interfere with the efficacy of OKT1-SAP, as in vitro treatment of fresh whole blood resulted in effective elimination of clonable peripheral blood T-lymphocytes assessed by a limiting dilution assay. Because these characteristics of T-lymphocyte killing by OKT1-SAP (ie, rapidity of action, potency also without potentiators) and lack of inhibition by whole blood components may be relevant for the use of an immunotoxin as a therapeutic agent in humans, the authors evaluated the stability in vivo and the circulatory clearance of OKT1-SAP in cynomolgus monkeys. Following a single intravenous (IV) injection of nontoxic dosages (0.16 to 1.3 mg/kg), an initial rapid decline (t1/2 alpha = 1.0 to 4.1 hours) was followed by a long-lasting slower decrease (t1/2 beta = 11.6 to 20.6 hours) of OKT1-SAP plasma concentrations as detected by double-antibody solid phase enzyme-linked immunosorbent assay (ELISA) assay. Not only did OKT1-SAP remain intact immunologically but it also retained its biological activity, as measured by the ability of plasma samples from monkeys given immunotoxin to inhibit DNA synthesis in human T-lymphocytes. Taken together the findings presented in this article indicate the feasibility of using OKT1-SAP as a therapeutic tool and provide information that will facilitate the rational use of immunotoxins as a treatment modality in humans.

Animals↗
PubMed1987

Arachidonic acid and LTB4 enhance aggregation of psoriatic peripheral blood mononuclear leukocytes in vitro.

The aim of the reported series of experiments was to examine the possible role played by arachidonic acid (Aa) derivatives in monocyte aggregation in psoriasis. Twenty patients with active plaque-type psoriasis covering not less than 20% of body surface area and 20 age-matched controls were investigated. Peripheral blood monocytes were harvested according to the technique recently set up by Colotta et al. These preparations usually contained more than 95% monocytes, as assessed by morphology and esterase staining. Aggregation tracings were plotted using a common platelet aggregation recorder system and expressed in arbitrary units. Aa sodium salt, acetylsalicylic acid (ASA), indomethacin, nordihydroguaiaretic acid (NDGA), and leukotriene B4 (LTB4) were used during testing. Aa induced an enhanced aggregation of mononuclear leukocytes (MNL) in psoriatic patients versus normal controls in a concentration-dependent way. Furthermore, neither ASA nor indomethacin inhibited Aa aggregation, while both markedly increased the aggregation response in psoriasis. LTB4 induced an enhancement aggregation in psoriasis, whereas NDGA strongly inhibited it. Although the pathophysiological significance of MNL aggregation described here remains obscure, assembly of the cells at the site of psoriatic skin might be a crucial event.

Adult↗