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M de la Garza

Publications and source records attributed to M de la Garza.

At least 19 recordsLinked to original sources
PubMed2005

The amoebicidal aqueous extract from Castela texana possesses antigenotoxic and antimutagenic properties.

Due to long-term treatment toxicity and clinical resistance to drugs commonly used against E. histolytica, new drugs against amoebiasis are urgently needed. Castela texana ("chaparro amargo") is a shrub taken traditionally in teas and capsules of dry plant to treat intestinal amoebic infections. An aqueous extract was prepared and its mutagenic, genotoxic and cytotoxicity properties were evaluated in prokaryotic and eukaryotic systems. This extract was neither mutagenic when evaluated with the Ames test in Salmonella typhimurium strains TA98, TA100 and TA102, nor genotoxic in unscheduled DNA synthesis in hepatocyte cultures, even at the highest concentrations tested. In fact, C. texana extract showed antimutagenic activity on S. typhimurium strains TA98 and TA100 in the Ames test. Furthermore, it was capable of protecting liver cell cultures against unscheduled DNA synthesis induced by 2-acetylaminofluorene at a concentration of 6.77 microg/ml. A free-radical scavenging test was used in order to explore the antioxidant capacity of C. texana extract with S. typhimurium strain TA102 pretreated with norfloxacin, a free radical producer. This extract showed a free radical withdrawal effect. The effective chemoprotective activity of this extract could be due to the antioxidant capacity of the C. texana extract components. In this paper it is shown that the antiamoebic natural product, C. texana, is also antimutagenic and protects against induction of preneoplastic lesions in rat liver. These results justify further studies to extend it use to human beings.

2-Acetylaminofluorene↗
PubMed2005

Subcellular fractions of Brucella ovis distinctively induce the production of interleukin-2, interleukin-4, and interferon-gamma in mice.

The aim of this study was to evaluate the effect of 3 Brucella ovis subcellular protein fractions: Outer membrane (OMP), inner membrane (IMP), and cytoplasm (CP), on cellular immune response by in vitro production of interleukin (IL)-2, IL-4, and interferon (IFN)-gamma. Each fraction was inoculated 3 times into Balb/c mice, primary cultures of mice spleen cells were done, and these were then stimulated with the fractions. Culture supernatants were collected at 24, 48, 72, 96, and 120 h postinoculation. Cytokine concentration was measured by Duoset-enzyme-linked immunosorbent assay (ELISA). The OMP fraction induced highest cellular immune response of 1000 pg/mL of IL-2 at 24 h, which decreased to < 100 pg/mL by 96 h. The IL-2 response for the IMP fraction was low at 24 h, but exceeded that of the OMP fraction at 72, 96, and 120 h. The CP showed a poor IL response. Regarding the IFN-gamma production, OMP and IMP induced a high response at 120 h. These results open the possibility for the use of B. ovis outer and inner membrane proteins as a subcellular vaccine.

Animals↗
PubMed2003

Antigenotoxic, antimutagenic and ROS scavenging activities of a Rhoeo discolor ethanolic crude extract.

Rhoeo discolor is a legendary plant used for treatment of superficial mycoses in Mexican traditional medicine. Despite its extended use, it is not known whether it has side-effects. An ethanolic crude extract from Rhoeo discolor was prepared, its mutagenic capacity was investigated by the Ames test, and its genotoxic activity in primary liver cell cultures using the unscheduled DNA synthesis assay. This extract was not mutagenic when tested with Salmonella typhimurium strains TA97, TA98 and TA100, and it did not elicit unscheduled DNA synthesis in hepatocyte cultures. In addition, we explored the antimutagenic and antigenotoxic activities of the extract and its ROS scavenger behaviour. Our results show that Rhoeo extract is antimutagenic for S. typhimurium strain TA102 pretreated with ROS-generating mutagen norfloxacin in the Ames test, and protects liver cell cultures against diethylnitrosamine induction of unscheduled DNA synthesis even at 1.9 ng per dish, which was the lowest dose tested. A free radical scavenging test was used in order to explore the antioxidant capacity of Rhoeo extract, as compared with three commercial well-known antioxidants quercetin, ascorbic acid and tocopherol. Rhoeo extract showed less radical scavenging effect than quercetin, but similar to that of alpha-tocopherol and more than ascorbic acid. It is important to note that this extract was neither mutagenic in S. typhimurium nor genotoxic in liver cell culture, even at concentrations as high as four- and 166-fold of those needed for maximal antimutagenic or chemoprotective activities, respectively.

Animals↗
PubMed2001

Expressed CYP4A4 metabolism of prostaglandin E(1) and arachidonic acid.

Cytochrome P4504A4 (CYP4A4) is a hormonally induced pulmonary cytochrome P450 which metabolizes prostaglandins and arachidonic acid (AA) to their omega-hydroxylated products. Although the physiological function of this enzyme is unknown, prostaglandins play an important role in the regulation of reproductive, vascular, intestinal, and inflammatory systems and 20-hydroxyeicosatetraenoic acid, the omega-hydroxylated product of arachidonate, is a potent vasoconstrictor. Therefore, it is important to obtain sufficient quantities of the protein for kinetic and biophysical characterization. A CYP4A4 construct was prepared and expressed in Escherichia coli. The enzyme was purified, and its activity with substrates prostaglandin E(1) (PGE(1)) and AA was examined in the presence and absence of cytochrome b(5) (cyt b(5)) and with a heme-depleted form of cyt b(5) (apo b(5)). The stimulatory role played by cyt b(5) in this system is not dependent on electron transfer from cyt b(5) to the CYP4A4 as similar stimulation was observed with apo b(5). Rapid kinetic measurement of CYP4A4 electron transfer rates confirmed this result. Both flavin and heme reduction rates were constant in the absence and presence of cyt b(5) or apo b(5). CD spectroscopy demonstrated that a conformational change occurred in CYP4A4 protein upon binding of cyt b(5) or apo b(5). Finally, acetylenic fatty acid inhibitors 17-octadecynoic acid, 12-hydroxy-16-heptadecynoic acid, 15-hexadecynoic acid, and 10-undecynoic acid (10-UDYA) were used to probe the substrate-binding pocket of CYP4A4. The short-chain fatty acid inhibitor 10-UDYA was unable to inhibit either PGE(1) or AA metabolism. All but 10-UDYA were effective inhibitors of CYP4A4.

Alprostadil↗
PubMed2001

Entamoeba histolytica: transferrin binding proteins.

Entamoeba histolytica trophozoites depend on iron for their growth; thus, they must use some host iron-containing molecules to fulfill this requirement. In this work we report that amoebas are able to utilize human holo-Tf as iron source and to recognize it through transferrin binding proteins. By use of an anti-human transferrin antiserum in an immunoblotting assay, two main polypeptides with apparent molecular masses of 70 and 140 kDa were found in total extract of trophozoites cultured in vitro. However, when a monoclonal anti-human transferrin receptor antibody was used, only one band with molecular mass of 140 kDa was observed. Both the human transferrin and the monoclonal antibody recognized a protein on the amoebic surface, demonstrated by confocal microscopy. Furthermore, the complex transferrin-transferrin binding protein was internalized by an endocytic process and probably dissociated inside the cell. This mechanism could be one manner in which E. histolytica acquires iron from the human host transferrin.

Animals↗
PubMed2000

Membrane vesicles released by Actinobacillus pleuropneumoniae contain proteases and Apx toxins.

Actinobacillus pleuropneumoniae serotype 1 releases vesicles containing proteases and Apx toxins into the culture medium. Vesicles were concentrated by ultracentrifugation and analyzed by electron microscopy and electrophoresis; their size ranged from 20 to 200 nm. A polyclonal antiserum raised against a purified high molecular mass secreted protease of serotype 1 recognized this protease on the surface of the vesicles by immunogold electron microscopy. Higher molecular mass polypeptides from vesicle extracts were recognized by the antiserum by Western immunoblot, indicating that the protease could form oligomers. However, these oligomers were not active against gelatin until secreted. Additionally, Apx toxins were also present in vesicles, and were recognized by Western immunoblot by an anti-serotype 1 toxins polyclonal serum. A. pleuropneumoniae antigens in vesicles were recognized by convalescent-phase pig sera from animals infected with serotype 1 or 5. The release of vesicles containing virulence factors could be a tissue damage mechanism in swine pleuropneumonia.

Actinobacillus pleuropneumoniae↗
PubMed2000

A 24-kDa cloned zinc metalloprotease from Actinobacillus pleuropneumoniae is common to all serotypes and cleaves actin in vitro.

Actinobacillus pleuropneumoniae causes pleuropneumonia in swine. This bacterium secretes proteases that degrade porcine hemoglobin and IgA in vitro. To further characterize A. pleuropneumoniae proteases, we constructed a genomic library expressed in Escherichia coli DH5alpha, and selected a clone that showed proteolytic activity. The recombinant plasmid carries an 800-base pair A. pleuropneumoniae gene sequence that.codes for a 24-kDa polypeptide. A 350-base pair PstI fragment from the sequence hybridized at high stringency with DNA from 12 serotypes of A. pleuropneumoniae, but not with DNA from Actinobacillus suis, Haemophilus parasuis, Pasteurella haemolytica, Pasteurella multocida A or D, or E. coli DH5alpha, thus showing specificity for A. pleuropneumoniae. The expressed polypeptide was recognized as an antigen by convalescent-phase pig sera. Furthermore, a polyclonal antiserum developed against the purified polypeptide recognized an A. pleuropneumoniae oligomeric protein in both crude-extract and cell-free culture media. This recombinant polypeptide cleaved azocoll, gelatin, and actin. Inhibition of the proteolytic activity by diethylpyrocarbonate suggests that this polypeptide is a zinc metalloprotease.

Actinobacillus Infections↗
PubMed1999

Secretion of proteases from Pasteurella multocida isolates.

The capability of Pasteurella multocida to secrete proteases to the culture medium and their characterization were studied in five animal isolates (bovine, chicken, sheep, and two from pig). All the isolates produced proteases in a wide range of molecular mass. It is suggested that they are neutral metalloproteases, since they were optimally active between pH 6 and 7, inhibited by chelating agents but not by other protease inhibitors, and reactivated by calcium. Proteases from isolates were able to degrade IgG. Several proteins from supernatants of cultures precipitated with 70% (NH4)2SO4 of all the P. multocida isolates were recognized by a polyclonal antiserum raised against a purified protease from Actinobacillus pleuropneumoniae. Protease production might play an important role during tissue colonization and in P. multocida diseases.

Actinobacillus pleuropneumoniae↗
PubMed1999

The clinically isolated FIZ15 bacteriophage causes lysogenic conversion in Pseudomonas aeruginosa PAO1.

FIZ15 bacteriophage, from a human clinical isolate of Pseudomonas aeruginosa, causes lysogenic conversion in the P. aeruginosa strain PAO1. The prophage-conferred phenotypes are: (1) increased resistance to phagocytosis by mouse peritoneal macrophages; (2) increased resistance to killing by normal human serum, and (3) increased adhesion to human buccal epithelial cells. These phenotypes are related to the prophage-induced change at the level of its own bacterial receptor, which appears to be the O-antigen.

Animals↗
PubMed1998

Entamoeba histolytica HM1:IMSS: hemoglobin-degrading neutral cysteine proteases.

Entamoeba histolytica HMI:IMSS trophozoites were able to utilize human hemoglobin but not hemin as a sole iron source to grow in vitro. Proteases from crude extracts of E. histolytica degraded human, porcine, and bovine hemoglobins at pH 7.0. These proteolytic activities were found by electrophoresis in SDS-polyacrylamide gels copolymerized with hemoglobin, with apparent molecular weights of 116, 82, and 21 kDa, the 82-kDa protein being the most active protease against this substrate. The proteases were classified in the cysteine group since the activities were inhibited by l-trans-epoxysuccinylleucylamido(4-guanidino)butane, p-hydroxymercuribenzoate, iodoacetate, and N-ethylmaleimide and activated with dithiothreitol. Other pathogenic strains of E. histolytica showed the same pattern of hemoglobinases. These hemoglobin-degrading proteases could be playing an important role in iron acquisition by E. histolytica.

Animals↗
PubMed1998

Purification and characterization of a protease from Actinobacillus pleuropneumoniae serotype 1, an antigen common to all the serotypes.

A high molecular-mass proteolytic enzyme of Actinobacillus pleuropneumoniae serotype 1, was purified from culture supernatants (CSN) by using DEAE-cellulose and sepharose-4B-gelatin chromatography. In 10% SDS-polyacrylamide gels copolymerized with porcine gelatin, the protease showed a single band of activity of > 200 kDa. However, minor molecular-mass proteolytic bands were observed when the protease was electrophoresed in the presence of either 5% beta-mercaptoethanol, 50 mM dithiothreitol, or 0.25 M urea. Furthermore, when the > 200-kDa purified protein was passed through a sucrose gradient, several bands with proteolytic activity were found: 62, 90, 190, and 540 kDa. The proteolytic activity was increased in the presence of calcium or zinc and was not affected after being heated at 90 degrees C for 5 min. Proteolytic activities were also observed in CSN from all A. pleuropneumoniae serotypes and biotypes. The purified protease hydrolyzed porcine IgA and IgG in vitro. In addition, by immunoblot the protease was recognized by serum of naturally infected pigs with serotypes 1 and 5, and by serum of pigs experimentally infected with serotypes 1, 2, 8, or 9. Serum of a pig vaccinated with CSN of a serotype 3 strain also recognized the protease, but not sera of pigs vaccinated with a bacterin (serotype 1). Proteins from CSN of all the serotypes, which were precipitated with 70% (NH4)2SO4, were recognized by a polyclonal antibody raised against the purified protease. Taken together these results indicate that an antigenic protease is produced in vivo by all the serotypes of A. pleuropneumoniae. The results indicate that proteases could have a role in the disease and in the immune response of pigs infected with A. pleuropneumoniae.

Actinobacillus pleuropneumoniae↗
PubMed1996

Entamoeba histolytica: proteinase secretion induced by collagen type I is dependent on cytoskeleton integrity.

Proteolytic activities of the protozoan parasite Entamoeba histolytica strain HM1:IMSS and the cytochalasin D-resistant mutant BG-3 were analyzed following stimulation with collagen type I and Ca2+, which induces electron-dense associated collagenase secretion. The mutant BG-3 had a protease activity of 73 kDa and secretion of total protease activity was not stimulated by collagen type I and Ca2+, which produced, in contrast, a 2-fold increase in protease secretion by the parental strain. This collagen-stimulated protease secretion was inhibited by cytochalasin D at a concentration of 1 microgram/ml. Cytochalasin D did not have any effect on the protease activity released by the mutant BG-3. These findings suggest that cytoskeleton integrity is necessary for collagen-induced protease secretion.

Animals↗
PubMed1994

Inhibition of 3T3 adipogenesis by retinoic acid is not mediated by cytoplasmic retinoic acid-binding protein.

Retinoic acid (RA) inhibits 3T3 adipogenesis in a dose-dependent and reversible manner, but its mechanism of action remains unknown. 3T3-F442A cell variants obtained by mutagenesis with nitrosoguanidine and/or selection with high RA concentrations showed different resistance to RA cytotoxicity and underwent adipose conversion of various extents when they were cultured in adipogenic conditions. Commitment to adipose differentiation was also inhibited by RA in these clones. Gel filtration chromatography showed the presence of a cytosolic RA-binding activity in the parental cells but not in three of the variant clones isolated. We demonstrate that cytoplasmic RA-binding activity is not essential for the inhibitory effects of the retinoid on 3T3 adipogenesis, or for resistance to RA cytotoxicity. Other mechanisms should be involved to explain the inhibition of adipose differentiation by RA.

3T3 Cells↗
PubMed1994

Entamoeba histolytica: electron-dense granule secretion, collagenase activity and virulence are altered in the cytoskeleton mutant BG-3.

HM-1:IMSS, a pathogenic strain of Entamoeba histolytica, and its mutant BG-3, identified by resistance to cytochalasin D, were tested for their capacity to: (i) secrete electron-dense granules; (ii) adhere and digest native type I collagen gels; and (iii) produce liver abscesses in new-born hamsters. The results demonstrate that the mutant has low adherence to collagen, low electron-dense granule secretion and collagenolytic activity, and low capacity to produce liver lesions in vivo, compared with the parental strain HM1:IMSS.

Animals↗
PubMed1994

Mycoplasma hyopneumoniae: interaction with other agents in pigs, and evaluation of immunogens.

Mycoplasmal pneumonia of swine causes considerable economic losses in porciculture. Diverse agents, such as environmental stress and infectious microorganisms, increase the possibility of infection, and the damage to pulmonary tissue when the infection is established. It is known that Mycoplasma hyopneumoniae has an important role in this disease, in addition to secondary microbial agents, such as Pasteurella multocida and Actinobacillus pleuropneumoniae. However, the characteristics of this disease in farms are well known. In this work we review the interactions among the different microorganisms involved and the immunological strategies utilized to control this disease. The interaction between Mycoplasma hyopneumoniae and P. multocida in experimental pneumonia was reported by us in conventional pigs. M. hyopneumoniae causes mild pneumonia, whereas P. multocida aggravates the pneumonia initiated by M. hyopneumoniae. The disease has been reproduced to test the efficacy of two immunogens, and can also be used to evaluate some antibiotics. A M. hyopneumoniae bacterine administered intraperitoneally conferred more protection than when it was used with adjuvant, although protection was not complete and colonization by M. hyopneumoniae was not prevented, as is claimed to have been the case with other vaccines.

Actinobacillus pleuropneumoniae↗
PubMed1994

Secreted proteases from Actinobacillus pleuropneumoniae serotype 1 degrade porcine gelatin, hemoglobin and immunoglobulin A.

It was found that 48 hour cultures of Actinobacillus pleuropneumoniae secreted proteases into the medium. Electrophoresis in polyacrylamide gels (10%) copolymerized with porcine gelatin (0.1%), of the 70% (NH4)2SO4 precipitate from the culture supernatants, displayed protease activities of different molecular weights: > 200, 200, 90, 80, 70 and 50 kDa. They had activity over a broad range of pHs (4-8), with an optimal pH of 6-7. All were inhibited by 10 mM EDTA, and reactivated by 10 mM calcium. They were stable at -20 degrees C for more than a month. The proteases also degraded porcine IgA and porcine, human, and bovine hemoglobin, although they appeared to be less active against the hemoglobins. The IgA was totally cleaved in 48 h, using supernatants concentrated with polyvinyl pyrrolidone or the 70% (NH4)2SO4. Extracellular proteases could play a role in virulence.

Actinobacillus Infections↗
PubMed1988

Pelvic exenteration for carcinoma of the cervix: analysis of 252 cases.

We present the results of 252 pelvic exenterations for primary and recurrent carcinoma of the cervix at the Hospital General de Mexico, a tertiary-care institution for the indigent. Emphasis is placed on the morbidity and mortality of the procedure in relation to patient selection. In underdeveloped countries, where early detection of cervical cancer is a rare event, pelvic exenteration must continue in the armamentarium of physicians; it can be associated with gains in the quality of life, with long-term survival, with effective rehabilitation, and possibly with cures.

Adult↗