PubMed Health⌕ Search

Biomedical subjects

G Simoni

Publications and source records attributed to G Simoni.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Highly sensitive chemiluminescent method for the detection of cell contamination.

Minisatellite analysis is commonly used in forensic disputes but can also be applied to the investigation of cell contamination. Such a problem arises, for example, when transplantation is performed. The presence of contamination has been investigated by other authors using radioactive methods. In the present study we describe a method that allows the detection of contamination with high sensitivity without using radioactive substances. Our technique is based on the use of polymerase chain reaction (PCR) amplification of minisatellite sequences (VNTR), followed by chemiluminescent detection. In particular, biotin-labelled dCTP is included in the PCR mixture and detection of PCR products is obtained following the CSPD chemiluminescent protocol (Southern-Light Nucleic Acid Detection Systems). We applied this method to artificial mixes of DNA of two individuals with alleles of different sizes. We performed progressive dilutions of an individual DNA into the other's DNA and revealed a contamination of 1 in 2500 cells. We also tested our technique searching for maternal contamination in cord blood samples in 60 cases and revealed a 18.3% contamination. The technique that we set up proves to be a very sensitive one which could be applied not only to the detection of maternal cells in cord blood but also in studying any other kind of contamination.

DNA↗
PubMedDate not supplied

Evidence for the direct inhibition of endothelin-1 secretion by hemoglobin in human endothelial cells.

The actual hemoglobin (Hb) contribution to endothelin-1 (ET-1) production in human umbilical vein endothelial cells (EC) was investigated. Cells were incubated with 0.1 mmol or 0.3 mmol of bovine: 1) unmodified (U) ferrous-Hb; 2) U-ferric-Hb; 3) U-ferryl-Hb; 4) polymerized low molecular weight (m.w.) Hb with chemically modified surface (< 400 kDa); and 5) glutaraldehyde polymerized, high m.w. Hb (< 1020 kDa). The incubation medium was tested at 6 and 24 hr for lactate dehydrogenase (index of cellular injury), and for ET-1 release by the cells. Before radioimmunoassay, the ET-1 was extracted from cell culture medium by a two-step purification procedure: 1) ultrafiltration, and 2) column extraction with C18 cartridges. The data suggested that the oxidation status of Hb and its concentration play an important role in causing EC injury. The highest toxicity was observed when EC were incubated with 0.1 mmol of ferryl-Hb, and there was no toxicity with 0.3 mmol of ferric-Hb. These results indicate that the ferric-Hb and low m.w. polymerized Hb at a concentration of 0.1 mmol did not alter ET-1 synthesis and produced a level similar to that of the control. However, it was found that ferryl-Hb and ferrous-Hb in a concentration of 0.1 mmol significantly reduced ET-1 release. All Hbs at a concentration of 0.3 mmol markedly inhibited the production of ET-1. The greatest decrease in ET-1 levels was produced by ferryl-Hb, and the lowest by ferric-Hb and low m.w. polymerized Hb. The Hb's inhibitory effect was more pronounced at 24 hr of incubation. It was also found that although Hb molecules showed a high degree of cross-reactivity with polyclonal anti ET-1 antibodies, the presence of different Hb solutions in the EC culture medium did not change the immunologic properties of ET-1 peptide. In conclusion, Hb inhibitory activity toward ET-1 production might be related to Hb mediated endothelial oxidative injury.

Animals↗
PubMedDate not supplied

A novel hemoglobin-adenosine-glutathione based blood substitute: evaluation of its effects on human blood ex vivo.

Chemically modified hemoglobin (Hb) solutions are under current investigation as potential red cell substitutes. Researchers at Texas Tech University have developed a novel free Hb based blood substitute product. This blood substitute is composed of purified bovine Hb cross-linked intramolecularly with o-adenosine-5'-triphosphate and intermolecularly with o-adenosine, and conjugated with reduced glutathione (GSH). In this study, we compared the effects of our novel blood substitute and unmodified (U) Hb, by using allogenic plasma as the control, on human blood components: red blood cells (RBCs), platelets, monocytes (Mo), and low-density lipoproteins (LDLs). The pro-oxidant potential of both Hb solutions on RBCs was examined by the measurement of osmotic and mechanical fragility, conjugated dienes (CD), lipid hydroperoxides (LOOH), thiobarbituric acid reactants (TBAR-S), isoprostanes (8-iso PGF2alpha) and intracellular GSH. The oxidative modification of LDLs was assessed by CD, LOOH, and TBAR-S, and the degree of apolipoprotein (apo) B cross-linking. The effects of Hb on platelets have been studied by monitoring their responses to the aggregation agonists: collagen, ADP, epinephrine, and arachidonic acid. Monocytes were cultured with Hb solutions or plasma and tested for TNF-alpha and IL-1beta release, then examined by electron microscopy. Results indicate that native UHb initiates oxidative stress of many blood components and aggravates inflammatory responses of Mo. It also caused an increase in RBC osmotic and mechanical fragility (p < 0.001). While the level of GSH was slightly changed, the lipid peroxidation of RBC increased (p < 0.001). UHb was found to be a stimulator of 8-iso PGF2alpha synthesis, a potent modulator of LDLs, and an effective potentiator of agonist induced platelet aggregation. Contrarily, our novel blood substitute did not seem to induce oxidative stress nor to increase Mo inflammatory reactions. The osmotic and mechanical fragility of RBCs was similar to that of the control. Such modified Hb failed to alter LDLs, increase the production of 8-iso PGF2alpha, but markedly inhibited platelet aggregation. The effect of this novel blood substitute can be linked with the cytoprotective and anti-inflammatory properties of adenosine, which is used as a cross-linker and surface modifier, and a modification procedure that lowers the hemoglobin pro-oxidant potential.

Adenosine↗
PubMedDate not supplied

[Congenital hypothyroidism screening program: preliminary results].

OBJECTIVE: The authors report early results of a screening program for Congenital Hypothyroidism in Santa Catarina, Brazil. METHODS: All the assays (82.709) analysed by Laboratório Central (LACEN) between July 1993 and December 1994 were studied. A blood sample was collected on filter paper for serum Thyroid Stimulating Hormone (TSH) measurement by fluoroimmunoassay, in triplicate. All children who had persistent abnormal TSH values (cord blood: TSH > 30 micro U/ml; from 2 to 7 days: >20 micro U/ml; older than 7 days: > 10 micro U/ml) were recalled for clinical evaluation. RESULTS: Out of 82.709 infants aged from 0 to 60 days (40% of the deliveries in this period), 304 presented abnormal results of TSH and 34 were confirmed as Congenital Hypothyroidism. The mean age of beginning the treatment was 45 days of life. CONCLUSIONS: The prevalence (1:2500) was higher than that observed in other countries, probably because some children had Transient Congenital Hypothyroidism. Nevertheless, sex prevalence was similar to that described in the literature. Clinical manifestations were inespecific which reinforces the importance of this kind of screening. Efforts have been done to improve the program in order to begin earlier treatment.

English Abstract↗
PubMedDate not supplied

Modified hemoglobin solution, with desired pharmacological properties, does not activate nuclear transcription factor NF-kappa B in human vascular endothelial cells.

The aim of the present study was to evaluate the role of hemoglobin (Hb) and the contribution of chemically modified Hb solutions on the activation of nuclear transcription factor. NF-kappa B, and propagation of oxidative stress within human vascular endothelial cells. The activation of an oxidative stress-sensitive NF-kappa B can be linked with the propagation of an inflammatory state via rapid induction of genes for several pro-inflammatory mediators. Human coronary artery endothelial cells (HCAEC) were cultured on glass coverslips or cell culture plates to confluence. Then, the cells were incubated for up to 18 hours with endothelial basal medium (EBM) supplemented with 5% FBS and test agents in a concentration of 0.1 and 0.2 mmol: 1) unmodified bovine Hb (UHb): 2) modified Hb solution polymerized with glutaraldehyde (GLUT-Hb), and 3) a novel modified Hb solution (Hb-PP-GSH) prepared according to our patented procedure (U.S. Patent No. 5,439,882). The positive control for the NF-kappa B activation study included a treatment of the cells with: I) endotoxin: IL-1; TNF; and H2O2. Results indicate that Hb's pro-oxidant potential was influenced by the type of chemical modification procedure. The GLUT-Hb autoxidation rate, peroxidase-like activity and reactivity with H2O2/ferryl species formation were higher as compared to UHb, by 15%, 35% and 30%, respectively. However, pro-oxidant potential of Hb-PP-GSH was significantly lower than that of UHb (by 22%, 12% and 28%, respectively). The extent of oxidative stress of the HCAECs was found to be the Hb modification-type and concentration dependent. Although the highest endothelial lipid peroxidation and the largest depletion of intracellular GSH was associated with 0.2 mmol of GLUT-Hb, the Hb-PP-GSH did not produce significant changes when compared to the control cells. The UHb generated a moderate oxidative stress to the endothelium. The immunofluorescent and EMSA results indicate a correlation between the type of Hb chemical modification and the induction of NF-kappa B nuclear translocation. We found that GLUT-Hb rapidly activated NF-kappa B and induced nuclear translocation. Treatment of the cells with an increasing amount of UHb leads to the partial nuclear induction of NF-kappa B. However, Hb-PP-GSH did not activate NF-kappa B directly. In this study, the positive control cells treated with endotoxin, IL-1 or TNF demonstrated full nuclear translocations, whereas H2O2 caused only partial induction. In conclusion, nuclear translocation of NF-kappa B by Hb solutions might be dependent on Hb's pro-oxidant potential and extent of Hb-mediated endothelial oxidative stress. Besides the low oxidative potential of Hb-PP-GSH, the observed lack of NF-kappa B activation by this Hb solution can be also related to the anti-inflammatory properties of adenosine which is used in our novel modification procedure. In this study, only the Hb-PP-GSH, cross-linked intramolecularly with o-adenosine triphosphate and intermolecularly with o-adenosine, and combined with reduced glutathiore, was shown to be non-toxic to the endothelium and promises to be an effective free-Hb based blood substitute.

Animals↗
PubMedDate not supplied

Expression of adhesion molecules and von Willebrand factor in human coronary artery endothelial cells incubated with differently modified hemoglobin solutions.

Previous studies have established a linkage between free Hb molecules and the production of inflammatory mediators by the reticuloendothelial cells. An important aspect of the endothelial response to the inflammatory stimuli is the expression of adhesion molecules on the luminal surface. Therefore, the present study was designed to investigate the effects of various free-Hb based oxygen carrying solutions on the intracellular adhesion molecule-1 (ICAM-1), the vascular cell adhesion molecule-1 (VCAM-1) and also von Willebrand factor (vWF) expression by human endothelium. Human coronary artery endothelial cells (HCAEC) were cultured on glass coverslips until they reached confluence, then incubated for 18 hours with endothelial basal medium (EBM) supplemented with 5% FBS and a 0.1 mmol or 0.2 mmol of the bovine Hb solutions: 1) pure unmodified bovine Hb (UHb); 2) modified bovine Hb solution (Hb-PP-GSH) prepared according to our newly developed procedure (U.S. Patent No. 5,439,882); and 3) modified bovine Hb solution polymerized with glutaraldehyde (GLUT-Hb). The HCAECs were also incubated with EBM (negative control) and EBM containing bacterial endotoxins in a concentration of 50 EU/ml (positive control). After treatment, cells were exposed to primary antibodies; anti-human ICAM-1, anti-human VCAM-1 or anti-human vWF, and consequently to the secondary antibody (fluorescein isothiocyanate-conjugated F(ab)2). Immunofluorescence analysis revealed different expressions of ICAM-1 and VCAM-1 on the surface membranes of variously treated cells. Although negative control cells had an undetectable level of adhesion molecules, the positive control cells, activated by endotoxin, exhibited high immunoreactivity for ICAM-1 and VCAM-1. The Hb's treated cells demonstrated differing degrees of activation. An insignificant expression of ICAM-1 was observed in HCAEC, following treatment with a 0.1 or 0.2 mmol of Hb-PP-GSH and 0.1 mmol of UHb. Cell treated with 0.2 mmol of UHb and both concentrations of GLUT-Hb demonstrated a massive expression of this adhesion molecule. A similar effects was observed during induction of VCAM-1. While a lack of expression was noted with both concentrations of Hb-PP-GSH and 0.1 mmol of UHb, the GLUT-Hb stimulated significant VCAM-1 induction at all tested concentrations. Immunofluorescence analysis confirmed the expression of vWF uniformly in HCAEC from the different experimental groups. The data suggest, vWF expression was unaffected by all but the GLUT-Hb treatment. In conclusion, the Hb stimulatory activity toward ICAM-1 and VCAM-1 inductions were related with the type of Hb chemical modification method. Although modification of Hb with glutaraldehyde potentiates adhesion molecules expression, our novel Hb modification procedure, which comprises intramolecular cross-linking with o-adenosine triphosphate and intermolecular with o-adenosine, and combined with reduced glutathione, apparently prevents these inflammatory events.

Animals↗
PubMedDate not supplied

Intrahepatic epidoxorubicin in metastatic and primary liver tumours: a phase II study.

Primary and metastatic gastrointestinal tumours in the liver have been treated by intrahepatic artery infusion of chemotherapeutic drugs in an attempt to increase the efficacy of the administered agents. Among the several active agents, 4' epidoxorubicin, an anthracycline analogue, was selected for this study because of the therapeutic level reached in the liver by this drug. Seven patients with primary hepatic carcinoma and twenty with metastatic adenocarcinoma of the colon to the liver received intraarterial hepatic infusion of epidoxorubicin at the dosage of 30 mg weekly. No haematological or gastrointestinal grade 3-4 toxicity was recorded, only one patient experienced transient cardiac toxicity. No objective response was observed in primary hepatic carcinoma and six objective responses, 1 complete and 5 partial (30%), were achieved in metastatic colorectal cancer patients. This results is not far from those reported with FUDR, but does not justify epidoxorubicin in colorectal cancer patients as first line intraarterial treatment.

Blood Cell Count↗
PubMedDate not supplied

Palliative chemoembolization of hepatocellular carcinoma with mitoxantrone, Lipiodol, and Gelfoam. A phase II study.

Transcatheter chemoembolization, in conjunction with various drugs, has been widely used for palliative treatment of hepatocellular carcinoma. A phase II study was carried out on mitoxantrone chemoembolization. High risk cirrhotic patients were excluded from this study. Fourteen mg/m2 mitoxantrone and up to 20 ml Lipiodol were injected, followed by Gelfoam embolization as indicated. Thirty-seven patients (33 with cirrhosis) were treated. Sixty-nine cycles were delivered, with mean (+/-SD) Lipiodol and emulsified mitoxantrone doses of 11.3+/-3.8 ml and 11.8+/-5.2 mg, respectively. Thirteen, 16, and 8 patients received one, two, and three cycles, respectively, with time intervals of 123+/-60 days. Thirty patients received Gelfoam embolization at the first cycle, 9 at the second and 4 at the third. No treatment-related deaths occurred. Complications were mild and transient, including nausea/vomiting in most cases, fever over 38 degrees C 67%, pain 74%, ascites 8%, jaundice 3%, bleeding 3%, pancreatitis 3%, myelosuppression 44%, diarrhea 5%. Treatment response rate was 49% (including 16% minor responses) with 16% early progressions. With a median follow-up of 12 months, the 12-month response duration and survival rates were 56% and 79% respectively. Transcatheter chemoembolization with mitoxantrone appears to be a promising method for the palliation of advanced hepatocellular carcinoma, and deserves to be evaluated in well controlled randomized studies.

Antineoplastic Agents↗
PubMedDate not supplied

Conventional isolated hyperthermic antiblastic perfusion in the treatment of recurrent limb melanoma.

Hyperthermic Antiblastic Perfusion (HAP) is a widely used method for the treatment of recurrent limb melanoma. In terms of tumor response, locoregional control and survival HAP has led to better results than those achieved with any other treatment. The aim of this report is to analyze our own experience with HAP in locally advanced limb melanoma. Thirty-two patients were submitted to HAP. HAP lasted 60 minutes, with maximal local temperature of 40.5-42 degrees C using melphalan 10 mg/L limb volume as antiblastic agent. Twenty patients had in-transit metastases and 12 local recurrence. Regional nodes were involved in 12 patients. Systemic leakage monitored with 125I or 99Tc ranged between 5-30% (mean 14%). No operative mortality nor major complications occurred. Local toxicity scored Wieberdink grade I in 8 patients, grade II in 17, grade III in 6 and grade IV in 1 case. Response rate (UICC) in the 16 patients treated with unexcised lesions was 94% (56% complete responses). With a median follow-up of 29 months (2-126) 14 patients relapsed after a median time of 10 months, and 17 patients are currently disease free, 3 of these are being reexcised and 3 re-perfused. Actuarial 5 years survival was 64%, with 39% disease free to the first relapse. Our results are consistent with the literature indicating HAP as a safe procedure with a high evidence of clinical responses.

Adult↗