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Biomedical subjects

J L Gómez

Publications and source records attributed to J L Gómez.

At least 19 recordsLinked to original sources
PubMed2005

Could the homologous sequence of anti-inflammatory pentapeptide (MLIF) produced by Entamoeba histolytica in the N protein of rabies virus affect the inflammatory process?

Amebiasis and rabies are public health problems, and they have in common a poor inflammatory effect in the target organs that they affect. In the GenBank, it was found that the anti-inflammatory peptide monocyte locomotion inhibitory factor (MLIF) produced by Entamoeba histolytica homologates 80%, with a fragment of the N protein of the rabies virus. We speculated if the N protein could contribute to the scant inflammatory reaction produced by rabies virus in central nervous system. The N protein was obtained and studied in vitro and in vivo. The N protein, as MLIF, inhibited the respiratory burst in human mononuclear phagocytes (43%, p<0.05), but in contrast to MLIF, it increased chemotaxis and it did not significantly inhibit delayed hypersensitivity skin reaction to 1-chloro-2-4-dinitrobenzene in guinea pigs. Therefore, the full peptide sequence has to be present or it has to be cleaved-free from the large recombinant N protein molecule (55 kDa) to become active.

Animals↗
PubMed2005

Comparison of commercial peroxidases for removing phenol from water solutions.

This paper describes a comparison between horseradish peroxidase (HRP) and soybean peroxidase (SBP), the two most widely used commercial peroxidases for the removal of phenol from wastewater. Both enzymes achieve maximal removal efficiency in a neutral pH medium although they are still quite active in a pH range of between 6.0 and 8.0. The fact that both enzymes show similar phenol elimination levels at any temperature between 25 and 40 degrees C is also of interest. Studies were carried out in the absence and presence of different concentrations of a stabilisation additive, polyethylene glycol (PEG), in an attempt to optimise the phenol elimination procedure. The final choice of peroxidase will depend on the characteristics of the effluent, operational requirements and on economic considerations. Our findings show that HRP acts faster than SBP but is more susceptible to inactivation, although it is better protected by PEG. In consequence HRP will be the most suitable choice but the addition of a sufficient amount of PEG is critical.

Biotechnology↗
PubMed2005

Posthemipelvectomy hernia.

We report the case of a white male who underwent a classic hemipelvectomy due to a femur fibrosarcoma with inguinal metastases, which 33 years later, developed into a posthemipelvectomy hernia in the amputation stump that impaired the use of his Canadian prosthesis. The hernia was repaired with a polypropylene mesh in a subaponeurotic position. A seroma was drained in the postoperative and it was only 2 months after the operation that he could use his prosthesis with any difficulty. A year after the operation, the hernia had not recurred. Only seven similar cases have been published, and there are only four cases with details of their correction, two with a mesh as was our case, and the rest with a primary suture of the aponeurotic borders. A brief review of the bibliography is given on this subject.

Femoral Neoplasms↗
PubMed2005

Effects of marathon running on plasma total homocysteine concentrations.

AIMS: There is evidence of an excess of acute cardiovascular (CV) events in marathon runners. High plasma total homocysteine (tHcy) concentrations are a recognised risk factor for CV events. Therefore, we investigated the changes in plasma tHcy concentrations 24h before and after a marathon race. METHODS AND RESULTS: Twenty-two non-professional male athletes, mean age 35.6 (6.6), range 23-49 years, were studied the day before and 24 h after finishing a marathon race. None of the athletes was a carrier of the MTHFR 677TT genotype and no ingestion of supplements of vitamins (B12, B6, folic acid) was allowed. RESULTS: Changes in plasma folate and plasma vitamin B12 concentrations were not detected post-race, but a significant increase in plasma tHcy concentrations was demonstrated. Plasma tHcy increased 19% 24h after the race. Before the race 20% of the subjects had a plasma tHcy concentration > 10 micromol/l (cut-off point for ischaemic heart disease risk), while after the race 50% had plasma tHcy concentrations> 10 micromol/l. CONCLUSION: An increase in plasma tHcy concentrations was observed after a marathon race in non-professional not well-trained male athletes performing strong physical activity. The potential physiological or pathological implications of this finding are unknown.

Adult↗
PubMed2003

[Non-pulsatile aneurysm of the superficial temporal artery: a report of a case].

Aneurysms of the superficial temporal artery are an uncommon cause for preauricular or parotid masses. Trauma is the most frequent etiology for a pseudoaneurysm and atheromatosis for the true aneurysm. The diagnosis is clinical due to their vascular signs (pulsatile mass, thrill...), these signs care not present when the aneurysmnas thrombosed, being this an unusual event that will make difficult a proper diagnosis. Radiological investigations are needed and helpful under these circumstances. Surgery is curative and recommended, being the excision after proximal and distal ligation of the artery the most accepted procedure. Aneurysms of the superficial temporal artery are rarely reported in the literature. We report a case that showed up as a non-pulsatile preauricular mass to highlight this unusual condition.

Aged↗
PubMed2001

Flow cytometric analysis of spontaneous and dexamethasone-induced apoptosis in thymocytes from severely malnourished rats.

Severe malnutrition is widely distributed throughout the world, showing a high prevalence in developing countries. Experimental animal models have been useful to study the effects of malnutrition at different levels and ages. Apoptosis is a well recognised process of cell death occurring under several physiological and pathological conditions. It represents the principal mechanism involved in cell selection in the thymus. Thymocyte apoptosis induction by dexamethasone is one of the best characterised experimental models of programmed cell death. The aim of the present study was to determine whether severe malnutrition increased spontaneous and/or dexamethasone-induced apoptosis in vivo in thymocytes of experimentally malnourished rats during lactation. Thymocytes were obtained from malnourished rats at weaning (21d of age). Apoptosis frequency was estimated by the terminal transferase-mediated dUTP nick end labelling assay. Spontaneous apoptosis was 1.9 (sd 1.0) % in well nourished rats in contrast to 13.3 (sd 3.8) % in malnourished animals; this is seven times greater (P<0.001). Interestingly, the frequency of dexamethasone-induced apoptosis was similar in both groups of animals (47.9 (sd 10.1) % in well nourished rats and 53.8 (sd 8.0) % in malnourished rats). The results obtained in the present study indicate that malnutrition is associated with a significant increase of spontaneously apoptotic cells. In addition, the data showed that the fraction of thymocytes susceptible to dexamethasone-induced apoptosis was similar in well nourished and malnourished animals. The greater levels of spontaneously apoptotic cells associated with malnutrition could be related to alterations of the microenvironment of the thymus and/or to an obstruction of early thymocyte maturation.

Animals↗
PubMed2000

Muscular dystrophy alters the processing of light acetylcholinesterase but not butyrylcholinesterase forms in liver of Lama2(dy) mice.

In order to know whether the histopathological changes of liver, which accompany muscular dystrophy, affect the synthesis of cholinesterases, the distribution and glycosylation of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) forms in normal (NL) and dystrophic Lama2(dy) mouse liver (DL) were investigated. About half of liver AChE, and 25% of BuChE were released with a saline buffer (fraction S(1)), and the rest with a saline-Brij 96 buffer (S(2)). Abundant light (G(2)(A) and G(1)(A)) AChE (87%) and BuChE (93%) forms, and a few G(4)(H) and G(4)(A) ChE species were identified in liver. The dystrophic syndrome had no effect on solubilization or composition of ChE forms. Most of the light AChE and BuChE species (>95%) were bound by octyl-Sepharose, while most light AChE forms (80%), but not BuChE isoforms (15%), were retained in phenyl-agarose. About half of the AChE dimers lost their amphiphilic anchor with phosphatidylinositol-specific phospholipase C (PIPLC), and the fraction of PIPLC-resistant species increased in DL. AChE T and R transcripts were detected by reverse transcriptase-polymerase chain reaction (RT-PCR) of liver RNA. ChE components of liver, erythrocyte, and plasma were distinguished by their amphiphilic properties and interaction with lectins. The dystrophic syndrome increased the liver content of the light AChE forms with Lens culinaris agglutinin (LCA) reactivity. The abundance of ChE tetramers in plasma and their small amount in liver suggest that after their assembly in liver they are rapidly secreted, while the light species remain associated to hepatic membranes.

Acetylcholinesterase↗
PubMed1999

Characterization of acetylcholinesterase and butyrylcholinesterase forms in normal and dystrophic Lama2dy mouse heart.

In searching for possible differences in acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) forms of dystrophic heart, the properties of ChE species in normal (NH) and dystrophic Lama2dy mouse heart (DH) were investigated. BuChE predominated over AChE. Loosely- and tightly-bound ChEs were released with saline (extract S1) and saline-Triton X-100 buffers (S2). About 50% of AChE, and 25% of BuChE, in NH or DH was measured in S1, and the rest in S2. Asymmetric AChE forms A12 (15%) and A8 (11%), globular hydrophilic G(H)4 (8%), amphiphilic G(A)4 (15%), and G(A)2+G(A)1 (51%) AChE species, and BuChE forms G(H)4 (13%), G(A)4 (3%), and G(A)2+G(A)1 (84%) were identified in NH and DH. Most of the asymmetric and G(A)4 AChE species were bound to Triticum vulgaris (WGA) or Ricinus communis (RCA) agglutinins. About half of G(H)4 and G(A)2+G(A)1 AChE were bound to WGA, and less (10%) to RCA. Variable amounts of G(H)4+G(A)4 (60%), and G(A)2+G(A)1 (75%) BuChE bound to WGA, and 50 and 10% to RCA. The lack of structural differences between ChE species in NH and DH indicates that, in contrast to the ChE forms in mouse skeletal muscle, the biosynthesis of ChE components in heart is not disturbed by dystrophy.

Acetylcholinesterase↗
PubMed1999

Amphiphilic properties of acetylcholinesterase monomers in mouse plasma.

Mouse plasma acetylcholinesterase (AChE) tetramers (G4) and dimers (G2) were retained by edrophonium-Sepharose, whereas AChE monomers (G1), and G4, G2 and G1 butyrylcholinesterase (BuChE) forms were not. Plasma G4 or G1 AChE did not differ in their affinity for edrophonium. G1 AChE, and G1 and G2 BuChE were retained in octyl-Sepharose, while G4 and G2 AChE, and G4 BuChE eluted freely. The amphiphilic behaviour of G1 AChE remained unmodified after incubation with trypsin. The electrophoretic mobility of the AChE monomers varied with the detergent added to the samples. The results show that mouse plasma G1 AChE possesses hydrophobic regions, which prevent its binding to the affinity matrix, and afford its interaction with octyl-Sepharose. The hydrophobic regions in G1 AChE probably provide conformational stability to disulfide-linked subunits in hydrophilic dimers.

Acetylcholinesterase↗
PubMed1999

[An alternative method to determine the radiochemical purity of the 99mTC-tetrofosmine preparations].

This paper describes a new quality control method to determine the radiochemical purity (RCP) value of Technetium-99m-Tetrofosmin preparations. The results of this procedure were compared with the results obtained with the method suggested by the manufacturer of the kit (classic method), consisting in thin-layer chromatography involving the use of a single strip of ITLC/SG as the stationary phase, and a acetone:dichlorometane 35:65 (Ac:DCM) solvent mixture as the mobile phase. The method that is proposed in this paper (alternative method) uses the same stationary phase but it is developed in a single solvent, methylethylketone (MEK). This method has the following advantages: a better capacity to separate the 99mTc-Tetrofosmin complex from 99mTcO4- and 99mTcO2 impurities, a faster chromatographic developing time and the use of a single solvent in the quality control.

Acetone↗
PubMed1996

Cell cycle phase duration in bone marrow cells from malnourished rats during suckling.

The generation time and duration of the different phases of the cell cycle were estimated in cultured bone marrow cells from malnourished and well-nourished rats during the lactation period by the percentage labeled mitosis (PLM) technique after a short pulse treatment with tritiated thymidine. The PLM were obtained in sequential analysis after every 3 h from removing labeled thymidine to 27 h of incubation. Results have shown a longer cell cycle time in cells from malnourished rats. The G1 + 1/2M phases are sensitive to experimental severe protein malnutrition (PCM), while S and G2 + 1/2 M phases did not show any differences in duration between malnourished and well-nourished rats.

Animals↗
PubMed1995

Chronic and acute ethanol treatment modifies fluidity and composition in plasma membranes of a human hepatic cell line (WRL-68).

The aim of this study was to compare the effects of chronic (0.1 mol/L ethanol exposure during 30 days) and acute (0.5 mol/L ethanol exposure during 24 h) ethanol treatment on the physical properties and the lipid composition of plasma membranes of the WRL-68 cells (fetal human hepatic cell line). Using fluorescence polarization we found that ethanol treatment reduced membrane anisotropy due to disorganization of acyl chains in plasma membranes and consequently increased fluidity, as measured with the diphenylhexatriene probe. Addition of ethanol in vitro reduced anisotropy in control plasma membranes, whereas chronically ethanol-treated plasma membranes were relatively tolerant to the in vitro addition of ethanol. Acutely ethanol-treated plasma membranes exhibited a smaller anisotropy parameter value than control plasma membranes. We found a decrease in total phospholipid content in acute ethanol WRL-68 plasma membranes. Cholesterol content was increased in both ethanol treatments, and we also found a significant decrease in phosphatidylinositol and phosphatidylcholine and an increase in phosphatidylethanolamine content in ethanol-treated plasma membranes. Our data showed that ethanol treatment decreased the anisotropy parameter consistently with increased fluidity, while increasing the cholesterol/phospholipid ratio of plasma membranes of WRL-68 cells, but only chronically ethanol-treated plasma membranes exhibited tolerance to the in vitro addition of ethanol. It is important to note that some changes that were interpreted as a result of chronic ethanol treatment were also present in short-period ethanol treatments.

Cell Line↗
PubMed1995

Congenital intracranial filariasis: a case report.

We present the case of a newborn with intracranial extra-axial collections which mere partially calcified. The underlying cause was shown to be filariasis which had been transmitted from the mother.

Adult↗
PubMed1995

Effect of renutrition on the proliferation kinetics of PHA stimulated lymphocytes from malnourished children.

The fraction of lymphocytes that responded to phytohemagglutinin (PHA) stimulation and initiated cellular proliferation (stimulation index or SI) was determined in groups of healthy and severely malnourished children. SI was determined again in the latter group after a period of nutritional recovery. The proportion of interphasic cells showing PHA response was assessed adding bromodeoxyuridine to the culture, so proliferative nuclei appear big and stain light blue, with dispersed granular chromatin and apparent nucleoli, while non-proliferative nuclei look small, stain red, and have compact and homogeneous chromatin. In mitotic nuclei, differential staining of sister chromatids made it possible to distinguish cells that had gone through one, two and three or more proliferation cycles. Based on the data obtained from interphase nuclei and mitosis, the SI was estimated at 48 and 72 h of culture. SI were higher in lymphocytes from healthy children than in those from children with severe malnutrition, even after the period of nutritional recovery. However, the SI was significantly higher in lymphocytes from malnourished children after nutritional recovery. Although in these children more cells are stimulated, there seems to be still damage that causes a cycling delay.

Bromodeoxyuridine↗
PubMed1994

Sister-chromatid exchange (SCE) and cell proliferation in lymphocytes from infected and non-infected children with severe protein calorie malnutrition (PCM).

The frequency of sister-chromatid exchanges (SCE) and the rate of cell proliferation were evaluated through differential staining of sister chromatids in mitogen-stimulated cultured lymphocytes sampled from five well-nourished children, from seven severely malnourished children infected with bacterium, and from 10 severely malnourished children following treatment for infection with antimicrobial drugs 2 weeks before blood sampling. The replication indices at 48 h of culture were higher in both groups of malnourished children than in the well-nourished children, indicating either a faster response to PHA and/or a shorter cell cycle in lymphocytes of these patients. The average frequency of SCE per mitosis was also significantly higher than in the control group. The mitotic index was similar in the three groups of children. The lack of significant difference in response between the two groups of malnourished children suggests that the effects observed at the cytogenetic level are caused by severe malnutrition per se, and not by any associated infection.

Cell Division↗
PubMed1994

Action of sodium fluoride on phagocytosis by systemic polymorphonuclear leucocytes.

Alterations in phagocytosis appear to be important in the onset and development of periodontitis. We investigated new substances that may be of use in the treatment of periodontitis. In a preliminary study, we tested the effect of sodium fluoride on phagocytosis by circulating polymorphonuclear leucocytes (PMNs) in 10 replicate assays using blood from six healthy subjects. Sodium fluoride was tested at concentrations of 1.0 micron to 4.0 microns against Streptococcus oralis, Streptococcus mutans, Streptococcus sobrinus and Streptococcus sanguis. The phagocytic index against all microorganisms increased significantly at all concentrations of sodium fluoride assayed; this effect was dose dependent. Sodium fluoride appeared to stimulate phagocytosis via two mechanisms: an apparent increase in bacterial susceptibility to phagocytosis, and direct stimulation of phagocytosis by PMNs.

Adult↗
PubMed1989

Four-day continuous infusion of cisplatin and 5-fluorouracil in head and neck cancer.

A combination of cisplatin and 5-fluorouracil, both administered 4 days continuously as infusion, was assessed in advanced head and neck cancer. Of the 37 patients studied, there were 15 complete and 17 partial responses (40.5% and 45.9%, respectively). Survival is 79.1% at 22 months. None of the patients in complete response has relapsed. In general toxic effects were moderate. Given as initial treatment, the regimen is effective and of considerable use in this type of patient.

Adult↗