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Biomedical subjects

C A Torres

Publications and source records attributed to C A Torres.

At least 19 recordsLinked to original sources
PubMed2006

Developmental changes in antioxidant metabolites, enzymes, and pigments in fruit exocarp of four tomato (Lycopersicon esculentum Mill.) genotypes: beta-carotene, high pigment-1, ripening inhibitor, and 'Rutgers'.

In surface cell layers of fleshy fruit, antioxidants must limit photooxidative reactions that generate reactive oxygen species (ROS) in high light. Our objective was to measure changes in the concentrations of antioxidant metabolites and pigments, and the activities of enzymes of the Mehler-peroxidase, ascorbate-glutathione cycle in fruit exocarp tissue under non-stress conditions of the following fruit-specific tomato (Lycopersicon esculentum Mill.=Solanum lycopersicum) mutants and their parent: (1) beta-carotene (B), (2) high pigment (hp-1), (3) ripening inhibitor (rin), and (4) the nearly isogenic wild-type 'Rutgers'. Developmental variables included days after anthesis (DAA) and fruit surface color. The highest total ascorbic acid (AsA) concentration was in the exocarp of immature green fruit of hp-1, being 32% higher than 'Rutgers'. The hp-1 mutant also had the highest chlorophyll and total carotenoid concentrations, comprised mostly of lycopene in red ripe fruit; whereas, beta-carotene comprised 90% of the carotenoids in B. Although enzyme activities varied within genotype, they generally increased with development, then decreased as fruit maturity was reached, being coupled with AsA and glutathione (GSH) concentrations. In all mutants, dark-green (DG) exocarp had more chlorophyll and protein, higher concentrations of reduced AsA and GSH, and usually lower enzyme activities than light-green (LG) exocarp taken from the same fruit.

Antioxidants↗
PubMed2001

Self-drainage lymphatic technique.

About 100 million people around the world have lymphedema; however, a large number do not have access to any kind of treatment. The current study reports on a technique of lymphatic self-drainage. The method consists of utilizing rods, bars, or any cylindrical object that rolls smoothly over the skin area to be drained. During this gliding motion a pressure of around 30 to 40 mm Hg should be exerted by the patient. The classical concepts of lymphatic drainage should be followed. This new method was subjected to a lymphoscintigraphic, anthropometric, and clinical evaluation demonstrating its usefulness in treating lymphedema.

Drainage↗
PubMed2000

Left ventricular myocardial adenosine triphosphate changes during reperfusion of ventricular fibrillation: the influence of flow and epinephrine.

OBJECTIVE: To determine whether epinephrine in combination with high flow worsens left ventricular (LV) myocardial high-energy phosphate stores during reperfusion of ischemic ventricular fibrillation (VF). DESIGN: Blinded, prospective block randomized, placebo controlled study. SETTING: University medical center research laboratory. SUBJECTS: A total of 22 mixed breed swine weighing 22.0+/-3.3 kg (SD). INTERVENTIONS: Open-chest swine, anesthetized with alpha-chloralose, underwent 10 mins of nonperfused VF followed by reperfusion with cardiopulmonary bypass for 90 mins and then defibrillation. Animals were block randomized to four groups for reperfusion: Group 1 (n = 5), high flow (100 mL/kg/min) and epinephrine (2.5 microg/kg/min); Group 2 (n = 5), high flow and placebo; Group 3 (n = 6), low flow (30 mL/kg/min) and epinephrine; and Group 4 (n = 6), low flow and placebo. MEASUREMENTS AND MAIN RESULTS: In vivo LV creatine phosphate (CP) and adenosine triphosphate (ATP) were determined using whole wall and spatially localized 31P NMR spectroscopy at 4.7 Tesla. During perfusion of the fibrillating myocardium, epinephrine significantly increased aortic pressure (p < .05) and improved defibrillation rates (p < .01). ATP levels during reperfusion were significantly decreased within all groups compared with baseline. There were no differences in ATP levels between groups. High flow, independent of epinephrine, was associated with increased preservation of ATP (p < .05), increased CP/ATP ratios (p < .02) in all layers of the LV wall, and decreased aortic and cardiac vein lactates (p < .001). CONCLUSIONS: Epinephrine, in combination with flow higher than standard cardiopulmonary resuscitation flows, increased perfusion pressure and defibrillation rates, but did not significantly alter myocardial ATP during VF reperfusion in the in vivo heart Reperfusion flow, independent of epinephrine, is a critical determinant of myocardial ATP preservation.

Adenosine Triphosphate↗
PubMed2000

Prevalence of anticardiolipin antibodies in peripheral arterial thrombosis.

The aim of this study was to assess prospectively the prevalence of anticardiolipin antibodies in patients with peripheral arterial thrombosis. Fifty-nine patients with arterial thrombosis (38 men, 21 women), ages ranging from 24 to 80 years, mean age, 45.5 years, were studied. The control group included 100 volunteer blood donors. After confirmation of the thrombotic event, anticardiolipin antibodies were dosed by the immunoassay enzyme method and by dilution. In Group I these antibodies were present in 62.7% of the patients, of which 33.9% were borderline and 28.8% were positive. In the control group 6% of the patients were borderline and 1% was positive. The statistical analysis showed that the prevalence found was statistically significant (p < 0.001), even when the borderline titers were not considered positive. Patients with peripheral arterial thrombosis have a high prevalence of anticardiolipin antibodies.

Adult↗
PubMed1999

DNA immunization: effect of secretion of DNA-expressed hemagglutinins on antibody responses.

DNA vaccines expressing plasma membrane and secreted forms of the influenza and measles virus hemagglutinins (HAs) have been used to evaluate the effect of secretion on DNA-raised antibody responses. At low doses of DNA, the plasma membrane form of the influenza virus HA raised higher titers of antibody than the secreted form. The isotype of the DNA-raised antibodies depended on both the method of DNA delivery and the form of the expressed antigen. Following intramuscular injections, DNAs expressing membrane bound forms of the influenza and measles HAs raised predominantly IgG2a. By contrast, DNAs expressing the secreted from of the two HAs as well as another secreted protein, human growth hormone, raised predominantly IgG1. Gene gun delivery resulted in predominantly IgG1 antibody responses for both secreted and membrane bound forms of the hemagglutinins. The raising of predominantly IgG1 by i.m. delivery of the secreted form of the influenza hemagglutinin was IL-4 dependent suggesting that a T-helper 2-biased immune response had been raised.

Animals↗
PubMed1999

In-vivo myocardial substrate alteration during perfused ventricular fibrillation.

OBJECTIVES: Earlier work suggests the in-vivo heart alters its substrate utilization as a function of cardiac work. Previous work has also demonstrated the high oxygen requirements of the heart during ventricular fibrillation (VF). The authors hypothesized that myocardial substrate utilization during VF with perfusion is similar to the normal beating heart under conditions of increased workload. METHODS: Myocardial substrate selection was studied in the in-vivo porcine myocardium using 13carbon nuclear magnetic resonance (13C NMR) under conditions of increased cardiac work (dobutamine group) and VF with extracorporeal perfusion (VF group). Once the animal preparation was completed, metabolic steady state was achieved with the infusion of unlabeled acetate into the left anterior descending (LAD) coronary artery. The infused substrate was then changed to [2-13C] acetate and glutamate pool labeling was monitored by 13C NMR. The glutamate C4 resonance areas at baseline and after intervention of either increased workload (dobutamine group) or perfused VF (VF group) were compared within groups using paired t-tests. RESULTS: Baseline aortic and great cardiac vein lactates, glucose levels, blood gases, hemoglobin levels, and temperatures were similar between groups. In both groups, there was a significant decrease from baseline in the labeling of C4 glutamate peaks (dobutamine group: 20.2+/-14.9 vs 84.7+/-32.7, p = 0.002; and VF group: 49.8+/-24.4 vs 83.9+/-24.4, p = 0.02), indicating selection against acetate oxidation in favor of other endogenous substrates. CONCLUSIONS: In the in-vivo heart, despite the absence of functional contractions, changes in substrate utilization during perfused VF are similar to changes that occur with increased workload in the normal beating heart.

Acetates↗
PubMed1998

Effect of oxytocin, prostaglandin F2 alpha, and clenbuterol on uterine dynamics in mares.

The effects of oxytocin, prostaglandin F2 alpha (PGF2 alpha), and clenbuterol on uterine contractility and tone during anestrus and diestrus, and during mobility and postfixation of the embryonic vesicle were studied in 51 pony mares. Contractility was assessed by scoring real-time ultrasound images, and tone was assessed by transrectal digital compression. Scoring was done by an operator who had no knowledge of treatment assignments. In anovulatory mares primed with progesterone for 16 d, oxytocin did not significantly alter contractility but did stimulate an increase in tone, whereas clenbuterol depressed both contractility and tone. The PGF2 alpha given on Days 12, 15, and 18 did not significantly alter uterine contractility in pregnant mares, but it increased contractility on all days in nonpregnant mares. Clenbuterol decreased both tone and contractility when given to pregnant mares on the day of embryonic-vesicle fixation, while it decreased tone but not contractility when given on Day 19. Clenbuterol treatment was associated with dislodgment of the fixed embryo in only 1 of 5 mares. However, on Day 19, clenbuterol treatment was associated with a change in shape of the conceptus when viewed in a cross section of the uterine horn. The conceptus shape became more circular rather than irregular or triangular, as indicated by a significant decrease in the variation in the distances between adjacent walls measured in 4 different directions. Results indicated that: 1) oxytocin increased uterine tone but did not alter contractility in progesterone-primed anestrous mares; 2) on Days 12, 15 and 18, PGF2 alpha increased uterine contractility in nonpregnant mares but not in pregnant mares; 3) clenbuterol decreased both tone and contractility at all reproductive states except for a lack of a decrease in contractility on Day 19 of pregnancy; and 4) reduction in uterine tone from clenbuterol treatment on Day 19 was associated with a change in the two-dimensional shape of the in situ conceptus from irregular to a more circular form.

Animals↗
PubMed1998

Effect of PGE2 on uterine contractility and tone in mares.

A technique for transvaginal, ultrasound-guided intrauterine injection was developed. After preliminary study using different approaches, the procedure was successful in 24 of 25 (96%) mares, based on detecting fluid in the uterine lumen during and after the injection. The technique was used to study the effect of PGE2, reportedly produced by the embryonic vesicle, on uterine contractility on Day 12 (Day 0 = ovulation). Uterine contractility was scored (1 = minimal, 4 = maximal) every 10 min for 1 h and every 30 min for the next hour by a continuous 1-min ultrasound examination of a longitudinal section of the uterine body without knowledge of group. In Experiment 1, the main effect of group (1-mL vehicle, n = 6; 0.25 microgram PGE2, n = 7) tended to be significant (P < 0.09), and the effect of time was significant (P < 0.008). The mean score was higher for the PGE2 group (2.0 +/- 0.1) than for the vehicle group (1.7 +/- 0.1). An increase in contractility occurred between 0 and 5 min in the vehicle group (P < 0.0004) and between 0 and 10 min in the PGE2 group (P < 0.04). In Experiment 2, there was a tendency (P < 0.08) for effect of group (control without injection, n = 6; 1-mL vehicle, n = 6; 0.025 microgram PGE2, n = 6). The PGE2 group (2.0 +/- 0.1) was different from the vehicle group (1.6 +/- 0.1) and the control group (1.6 +/- 0.1). An increase in contractility occurred between 0 and 20 min in the PGE2 group, and the changes were not significant in the other groups. However, scores were higher in the PGE2 group before treatment, and there were no significant effects when data were converted to percentage changes. The results for an effect of intrauterine treatment of PGE2 on uterine contractility are considered uncertain because of the transient increase in contractility from vehicle injections in Experiment 1 and the higher score in the PGE2 group before treatment, with no significant differences in percentages in Experiment 2. Indirectly, however, an effect of PGE2 was suggested by a shorter (P < 0.05) period of detectability of intrauterine fluid in the PGE2 groups (21 +/- 31 min) than in the vehicle groups (50 +/- 42 min). The shorter period was attributable to greater dispersion of the fluid as a result of increased contractility. In Experiment 3, PGE2 (10 mg, n = 5) and vehicle (4 mL, n = 5) were given intravenously. In addition to uterine contractility, uterine tone was scored (1 = minimal, 4 = maximal) by transrectal digital compression. The main effect of group was significant (P < 0.03) for uterine contractility score, which increased between 0 and 20 min after PGE2 injection. The time effect and interaction were highly significant (P < 0.0001) for uterine tone score, and tone increased in the PGE2 group between 0 and 20 min after injection. The results indicated that PGE2 should be considered as a potential stimulator of both uterine contractions and uterine tone during the time of embryo mobility in mares.

Animals↗
PubMed1997

The dominant role of bone marrow-derived cells in CTL induction following plasmid DNA immunization at different sites.

Although plasmid DNA immunization provides an effective means of inducing CTL responses to an expressed Ag, the mechanism by which CTL precursors are activated remains to be established. Insights could be gained by identifying the cells responsible for Ag presentation when DNA is introduced into different tissue sites. By immunizing parent into F1 bone marrow chimeric mice with an influenza nucleoprotein-expressing plasmid, we have demonstrated that the key cells in this presentation process for both gene gun-mediated epidermal injection and needle intramuscular injection of plasmid DNA are bone marrow derived. Furthermore, as assessed by intramuscular injection, coexpression of nucleoprotein with the costimulatory molecule B7-2, or the cytokines granulocyte-macrophage CSF and IL-12, did not convert nonhemopoietic cells into APCs. Thus, for two distinctly different modes of DNA immunization, in one case with or without coexpressed immunostimulatory factors, the APCs were consistently found to be of hemopoietic origin.

Animals↗
PubMed1997

Differential dependence on target site tissue for gene gun and intramuscular DNA immunizations.

Surgical ablations revealed different dependencies on the injection site tissue for i.m. needle and epidermal gene gun DNA immunizations. Excision of an injected muscle bundle within 10 min of DNA inoculation did not affect the magnitude or longevity of Ag-specific Ab responses. By contrast, biopsy of the skin target site up to 24 h after gene gun bombardment completely abrogated the Ab response in the majority of mice. The form of a DNA-expressed Ag (membrane bound, secreted, or intracellular) did not affect the temporal requirements for the skin and muscle target sites. Skin cells, but not muscle cells, were also required for DNA-induced CTL. We conclude that transfected cells in gene gun-bombarded skin, but not needle-injected muscle, play a central role in DNA-initiated Ab and CTL responses.

Animals↗
PubMed1997

DNA vaccines.

DNA vaccines use eukaryotic expression vectors to produce immunizing proteins in the vaccinated host. Popular methods of delivery are intramuscular and intradermal saline injections of DNA and gene gun bombardment of skin with DNA-coated gold beads. The method of DNA inoculation (gene gun versus intramuscular injection) and the form of the DNA-expressed antigen (cell-associated versus secreted) determine whether T-cell help will be primarily type 1 or type 2. Mechanistically, gene gun-delivered DNA initiates responses by transfected or antigen-bearing epidermal Langerhans cells that move in lymph from bombarded skin to the draining lymph nodes. Following i.m. injections, the functional DNA appears to move as free DNA through blood to the spleen where professional antigen presenting cells initiate responses. Preclinical trials with DNA vaccines have had outstanding success. DNA-based immunizations have provided protection against viral, bacterial and parasitic diseases, modulated the effects of autoimmune and allergic disease, and provided some hope for the control of cancer.

Antigen Presentation↗
PubMed1996

Genetic manipulation of Vibrio cholerae for vaccine development: construction of live attenuated El Tor candidate vaccine strains.

The recent spread of El Tor cholera to America augments the need for an effective, safe and economical vaccine. In the present paper we describe the construction of live attenuated V. Cholerae strains by specifically deleting the genes encoding cholera toxin and other putative toxins from the bacterial chromosome. To maximize the likelihood of exposing protective antigens relevant to currently circulating vibrios we selected for genetic manipulation recent epidemic V. cholerae isolates from Peru. The mutant strains did not produce cholera toxin in vitro and in vivo. Deletion of the virulence cassette was accompanied by marked attenuation in the infant mouse cholera model. A selected El Tor Ogawa candidate vaccine strain was refractory to acquisition of foreign genes by conjugation with toxigenic vibrios.

Animals↗
PubMed1994

Isolation of HIV-1 from Filipino commercial sex workers (CSWs).

Peripheral blood mononuclear cells (PBMC) from 36 HIV-1 antibody positive Filipino female commercial sex workers (CSWs) were co-cultivated at a 1:1 ratio with phytohemagglutinin-P activated PBMC from healthy, HIV-1 antibody negative donors. After 3-18 (mean 7.2) days of incubation at 37 degrees C in 5% CO2, 29 cultures showed evidence of replication of HIV-1: increasing concentrations of p24 antigen in the growth medium and the appearance of multinucleated giant cells. Although the length of incubation required for the appearance of cytopathogenic effect for each particular isolate was essentially the same when either 6 microwell plates were seeded with 3.0 x 10(6) cells/well or 24 well plates were seeded with 1.5 x 10(6) cells/well, the 24 well format was more sensitive. The ability to isolate HIV-1 from PBMC did not appear to be associated with the progression of disease or the presence or absence of any specific clinical findings. However, if the PBMC were from individuals with a concomitant p24 antigenemia, the incubation time required for isolation was significantly shorter (mean 3.8 days). The absolute CD4+ lymphocyte count was also slightly reduced in the culture positive, p24 antigenemic patients (range 302-813 cells/mm3, mean 502 cells/mm3) compared to the culture positive, p24 serum negative cases (range 311-1,511 cells/mm3, mean 830 cells/mm3). The p24 serum negative cases with CD4+ counts of < 500 cells/mm3 had positive PBMC cultures by 6 days of incubation.(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS Serodiagnosis↗
PubMed1987

Development of a practicable method for isolation and identification of dengue viruses in developing countries.

We sought a practicable method for isolation and identification of dengue viruses in South-East Asia. We compared two mosquito cell lines, C6/36 and TRA-284-SFG, for virus isolation and two identification methods, immunofluorescent staining of infected cells with serotype-specific mouse monoclonal antibodies and a sandwich-type enzyme-linked immunosorbent assay with conventional mouse hyperimmune ascitic fluids. We found that the combination of TRA-284-SFG cells and ELISA is a useful and feasible method in developing countries.

Animals↗
PubMed1986

Effects of the antitumor drugs 3-nitrobenzothiazolo[3,2-alpha]quinolinium and fagaronine on nucleic acid and protein synthesis.

3-Nitrobenzothiazolo[3,2-alpha]quinolinium perchlorate (NBQ) has been shown to be active against in vivo experimental tumors of P388 and Ehrlich ascites cells. Furthermore, it has been established that NBQ binds to DNA by intercalation. In this work we describe its effects on DNA, RNA and protein syntheses both in KB cells and in cell-free synthesizing systems. Fagaronine, an alkaloid structurally related to NBQ, was studied also in an attempt to establish the basis for future studies on structure-activity relationships. Both NBQ and fagaronine inhibited DNA, RNA and protein syntheses in KB cells, with essentially equal effectiveness. Exposure of KB cells to NBQ for 2 hr caused irreversible inhibition of DNA, RNA and protein syntheses. Studies in cell-free systems showed that NBQ strongly inhibited Escherichia coli DNA polymerase I, whereas RNA polymerase activities were moderately affected. Furthermore, both drugs inhibited protein synthesis in cell-free systems derived from rabbit reticulocytes and Saccharomyces cerevisiae. Our results indicate that NBQ and fagaronine exert their cytotoxic activity by at least two independent mechanisms: inhibition of DNA activity by binding to this molecule, and inhibition of protein synthesis probably by interacting with the ribosomal system.

Alkaloids↗
PubMed1984

Persistence of Q strain of H2N2 influenza virus in avian species: antigenic, biological and genetic analysis of avian and human H2N2 viruses.

The characteristics of an avian influenza virus were compared in detail with those of human Asian (H2N2) influenza viruses. Antigenic analysis by different antisera against H2N2 viruses and monoclonal antibodies to both the hemagglutinin and neuraminidase antigens showed that an avian isolate, A/duck/München/9/79 contained hemagglutinin and neuraminidase subunits closely related to those of the early human H2N2 viruses which had been prevalent in 1957. However, this avian virus gave low HI titers with absorbed and non-absorbed antisera to different human H2N2 viruses isolated in 1957. Like human Q phase variant, such as A/RI/5-/57 (H2N2), hemagglutination of the above avian strain was not inhibited by the purified non-specific gamma-inhibitor from guinea pig serum. Growth behavior at restrictive temperature (42 degrees C) clearly differentiate the avian H2N2 virus from human influenza viruses, showing that the former virus grew well in MDCK cells at 42 degrees C but not the latters. Genomic analysis of these viruses revealed that the oligonucleotide map of H2N2 virus isolated from a duck was quite different from those of human H2N2 viruses from 1957 to 1967. The oligonucleotide mapping also indicated that different H2N2 influenza virus variants had co-circulated in humans in 1957.

Animals↗
PubMed1983

Cefuroxime, thiamphenicol, spectinomycin, and penicillin G in uncomplicated infections due to penicillinase-producing strains of Neisseria gonorrhoeae.

The use of cefuroxime and thiamphenicol in uncomplicated gonococcal infection was studied in 562 women confined to a clinic to preclude reinfection before cultural confirmation of cure. Cefuroxime was as effective as spectinomycin in the treatment of infections due to penicillinase-producing strains of Neisseria gonorrhoeae (PPNG) and was significantly more effective than 4.8 units of aqueous procaine penicillin G with probenecid among non-penicillinase-producing (non-PPNG) strains. Thiamphenicol was highly effective against PPNG, but the failure rate in infections with non-PPNG was high and appeared to be related to the minimum inhibitory concentrations of thiamphenicol. This rate was not, however, significantly higher than that for PPNG strains. Thiamphenicol might therefore be used as an alternative for infections due to PPNG strains. If, however, thiamphenicol is used widely, selection of more resistant strains and thus an increasing proportion of failures may be expected.

Adolescent↗