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Biomedical subjects

M Lopez

Publications and source records attributed to M Lopez.

At least 595 records · Page 33Linked to original sources
PubMedDate not supplied

Infusion of large quantities of autologous blood monocyte-derived macrophages in two cancer patients did not induce increased concentration of IL-6, TNF-alpha, soluble CD14 and nitrate in blood plasma.

In an attempt to increase the number of macrophages available for reinfusion in immunotherapy trials, GM-CSF was injected in vivo to mobilize circulating blood monocytes in 2 cancer patients. Subsequently mononuclear cells were collected by apheresis, cultured in the presence of GM-CSF and activated with IFN-gamma. This procedure resulted in the harvesting of 1.3 to 3.1 x 10(9) (mean 2 x 10(9)) macrophages per apheresis, product which was very well tolerated at autologous reinfusion. These infusions did not induce increased levels of TNF-alpha, IL-6, soluble CD14 nor nitrates in blood plasma (or urine). The lack of TNF-alpha and IL-6 release in blood plasma could explain the good tolerance of these infusions. No in vivo anti-tumoural activity of these high numbers of infused macrophages could be observed.

Antigens, CD↗
PubMedDate not supplied

Neurophysiological examination of end-plate function in patients with lung cancer.

Twenty-eight patients affected by lung cancer were studied with neurophysiological and clinical examinations to show the prevalence of alteration of neuromuscular transmission. During repetitive stimulation at 20 Hz we found in 6 cases (22%) an increment (> 20%) and in 4 cases a decrement ( > 10%) of the size of muscle action potentials. In 15 patients (57%) we found low sensory action potential amplitude (< 11 uv). In 3 (11%) of the 6 cases with incremental response the overall examination suggested a disorder of neuromuscular junction such as Eaton-Lambert syndrome. Our results suggest that the peripheral nervous system involvement in patients affected by lung cancer is higher than usually estimated.

Action Potentials↗
PubMedDate not supplied

Increased in vitro tumour necrosis factor-alpha production in iron deficiency anemia.

In vitro monocyte-derived tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) production was assessed in iron deficient with anemia (IDA), iron deficient without anemia (ID) and control infants. The concentrations of released and cell-associated cytokines were measured before and after 3 months of iron supplementation in all groups (ferrous sulphate drops: 3 mg/Kg/day). No difference in released and cell-associated IL-1 beta was observed between either groups of infants. Lipopolysaccharide-stimulated blood mononuclear cells from IDA (n = 9) infants produced a significantly higher immunoreactive TNF-alpha concentration as compared to ID (n = 9) and normal subjects (n = 18) on admission (F = 6.72; p < 0.004). After iron therapy, the LPS stimulated TNF-alpha secretion by cells of IDA infants returned to the levels observed in the other groups. Since TNF-alpha plays a key role in iron metabolism, we speculate that increased TNF production in IDA infants could exacerbate the inhibition of erythroid proliferation present in these conditions. Further studies are needed to evaluate the effect of more severe anemia as well as to clarify the biological effect of increased TNF-alpha production in iron deficiency anemia and its consequences.

Analysis of Variance↗
PubMedDate not supplied

Immune control of neoplasia by adoptive transfer of macrophages: potentiality for antigen presentation and gene transfer.

Human macrophages could be differentiated from mononuclear precursors present in the blood circulation. After IFN-gamma activation, they became antitumoral and adhered to transformed cells. Low amounts of activated macrophages (MAK) caused regression of experimental tumors in animal models. In cancer patients, MAK were well tolerated and caused tumor necrosis but no clear therapeutic response has been reported up to now. Improvements can be expected using local treatment and more specific macrophages presenting tumor antigens. This restoration of immune recognition of growing tumors with low levels of reactants should ultimately reestablish, after exogenous stimulation, the insufficient immune response of the host against a malignant tumor. Antitumoral macrophages can also be optimized by gene transfection. Macrophages are proposed as stable and long lasting cell vectors for adoptive gene treatments.

Animals↗
PubMedDate not supplied

Primary gastric lymphoma.

Primary gastric lymphoma is the most frequent non-Hodgkin's lymphoma (NHL) of extranodal origin (25%). It accounts for 5% of all NHL and 4% of primary gastric malignancies. Recent studies suggest its origin from B-cell immune system. The majority of these tumors are high-grade centroblastic and immunoblastic subtype. The extent of disease is by far the most important guide to prognosis. Patients with gastric lymphoma usually recur in the gastrointestinal tract, but one-half of those recurring in abdomen also have tumor spread to extra-abdominal sites. Gastrectomy as a single treatment modality cures about one-third of patients with gastric lymphoma. The role of adjuvant therapy both in terms of radiotherapy and chemotherapy is not sufficiently known. In advanced stage when chemotherapy is indicated, CHOP combination seems to be appropriate in favorable prognostic situation, whereas aggressive third-generation combinations should be used for unfavorable cases.

Humans↗
PubMedDate not supplied

Protein-tyrosine phosphatase activity of Coxiella burnetii that inhibits human neutrophils.

Supernatants prepared from disrupted Coxiella burnetii possess acid phosphatase (ACP) activity that apparently accounts for the inhibition of the metabolic burst of formyl-Met-Leu-Phe(fMLP)-stimulated human neutrophils. Results are presented regarding purification and biochemical-biological characterization of the ACP. The highly purified enzyme, which exhibited an apparent M(r) of 91 K and optimal activity at pH 5.0, also inhibited neutrophils. The enzyme retained full activity at pH 4.5, 5.5, and 7.4, when incubated overnight at 0 degrees C and room temperature; at pH 5.5, it retained full activity after overnight incubation at 37 degrees C. Apparently, the enzyme contains asparagine-linked but not serine- or threonine-linked glycan residues since its treatment with N-glycosidase F (PNGase F) decreased its M(r) to 87 K and no changes were detected with O-glycosidase. The enzyme's capacity to hydrolyze phosphate from a number of phosphate-containing compounds was examined; five phosphocompounds were significantly hydrolyzed: 5'-CMP > fructose 1,6-diphosphate > tyrosine phosphate > 3'-AMP > 5'-AMP. The ACP also dephosphorylated (32)P-Raytide, a phosphotyrosine-containing peptide. Dephosphorylation of Raytide was inhibited by the following phosphatase inhibitors: sodium molybdate, potassium fluoride, sodium ortho-vanadate and D2, a heteropolymolybdate compound. These results indicate that C. burnetii ACP may play a role in disrupting tyrosine phosphorylation/dephosphorylation reactions associated with the signal transduction pathway culminating in the metabolic burst. Interestingly, Western blot analysis of ACP-inhibited neutrophils showed a marked increase in tyrosine phosphorylation of a 44 K protein as compared to uninhibited cells.

Acid Phosphatase↗
PubMedDate not supplied

Capillary electrophoresis for purity estimation and in-process testing of recombinant GB virus-C proteins.

Protein purity estimation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) coupled with scanning densitometry is a critical component in the manufacture of recombinant proteins for commercial diagnostic assays. However, the procedure is time consuming and often difficult to reproduce because commercial dyes that are used for visualizing proteins do not bind in a stoichiometric fashion for all proteins. The present report describes the use of a rapid and dye-independent SDS polymer-filled capillary gel electrophoresis (CE-SDS) method to estimate protein purity. The CE-SDS method was used for in-process and final purity testing of GB virus-C (GBV-C) fusion proteins produced in E. coli, and was directly compared with the conventional SDS-PAGE method using purified Coomassie blue dye to reduce protein staining anomalies. The CE-SDS method may serve as an alternative or replacement method to the lengthy and tedious SDS-PAGE method. This study also demonstrates that the observed molecular weight of the fusion protein, determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), provides higher accuracy than values estimated by either CE-SDS or SDS-PAGE methods.

Cloning, Molecular↗
PubMedDate not supplied

Purity testing of recombinant proteins by capillary electrophoresis.

Purity testing of recombinant DNA (rDNA) proteins using slab gel electrophoresis in conjunction with scanning densitometry is time consuming and labor intensive and is difficult to reproduce because the dyes used for visualizing proteins do not bind in a stoichiometric fashion for all proteins. The present report describes a micellar capillary zone electrophoresis (MCZE) procedure that overcomes these difficulties. The MCZE method was evaluated to estimate protein purity of hydrophobic cytomegalovirus proteins, expressed E. coli, and highly glycosylated hepatitis C virus proteins, expressed in Chinese hamster ovary cells. The results obtained by the MCZE procedure correlated very well with the purity results quantitated by the conventional slab gel electrophoresis method using purified Coomassie Brilliant Blue dye to reduce anomalies. MCZE may serve as an alternative method for in-process and purity testing of rDNA proteins.

Animals↗
PubMedDate not supplied

Dexrazoxane cardioprotection in advanced breast cancer patients undergoing high-dose epirubicin treatment.

PURPOSE: We performed a randomized trial to evaluate the cardioprotective effect of dexrazoxane (DEX) in advanced breast cancer patients (ABC) treated with high single-dose epirubicin (EPI). A secondary objective was to determine the role of radioimmunoscintigraphy (RIS) in the assessment of epirubicin cardiotoxicity. PATIENTS AND METHODS: Ninety-five patients with ABC were treated with EPI 160 mg/m2 by i.v. bolus every 3 weeks with or without DEX, 1,000 mg/m2 i.v. Cardiac monitoring included multigated radionuclide (MUGA) scan with determination of resting left ventricular ejection fraction (LVEF), and RIS with 111-Indium antimyosin monoclonal antibodies. RESULTS: The overall response rate was 69% in the EPI arm and 67% in the EPI + DEX arm; median time to response and median time to progression were identical in both arms, being 2 and 8 months, respectively. Median survival was 19 months versus 29 months (p 0.21), respectively. DEX did not appear to contribute to extracardiac EPI toxicity. Congestive heart failure occurred only in the EPI arm (2 instances). LVEF significantly decreased from baseline only in the EPI group. An abnormal tracer uptake at RIS was observed early in both arms, but the increase in heart to lung ratio was much more evident in the control group. CONCLUSIONS: DEX significantly protects against the development of high dose epirubicin cardiotoxicity apparently without evidence of an adverse impact on antitumor activity and non cardiac toxicity. RIS is a very sensitive technique in detecting anthracycline cardiac damage, but its specificity is low and cannot be considered alone a primary test for guiding anthracycline treatment.

Aged↗