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Biomedical subjects

A Toledo

Publications and source records attributed to A Toledo.

At least 19 recordsLinked to original sources
PubMed2006

Further evaluation of the synthetic peptide vaccine S3Pvac against Taenia solium cysticercosis in pigs in an endemic town of Mexico.

Taenia solium cysticercosis is a parasitic disease frequently affecting human health and the pig industry in many developing countries. A synthetic peptide vaccine (designated S3Pvac) against porcine cysticercosis has been developed previously as an aid to interrupt transmission and has been shown to be effective. The results of the present study support the effectiveness of the vaccine under endemic field conditions. However, given the time-frame of the vaccination trial, no changes in the local levels of transmission were detectable before and after vaccination using sentinel pigs. Thus, this investigation shows the limited usefulness of single vaccination as the sole means of interrupting Taenia solium transmission in an endemic region.

Animals↗
PubMed2006

Intrahepatic DNA vaccination: unexpected increased resistance against murine cysticercosis induced by non-specific enhanced immunity.

Experimental murine cysticercosis caused by Taenia crassiceps has proved to be a useful model with which to test the efficacy of new vaccine candidates and delivery systems against pig cysticercosis. A high level of protection against murine cysticercosis was previously observed by intramuscular or intradermal DNA immunization with the use of the sequence of the recombinant KETc7 antigen cloned in pcDNA3 (pTc-sp7). To determine the effect of KETc7 differential expression in DNA vaccination, KETc7 was cloned in pGEM 11Zf(+) under the control of the tissue-specific regulatory promoter phosphoenolpyruvate carboxykinase (pPc-sp7). A high level of protection was induced by intrahepatic immunization with pPc-sp7, pTc-sp7 and the empty vector in the absence of any specific immunity. The empty vector pGEM 11Zf(+), the plasmid with the highest content of CpG sequences, provided to the most efficient protection. This protection was related to an increased number of splenocytes, enhanced nonspecific splenocyte proliferation, and intensified intrahepatic INF-gamma production. Overall, intrahepatic plasmid CpG-DNA immunization provokes an exacerbated nonspecific immune response that can effectively control Taenia crassiceps cysticercosis.

Animals↗
PubMed2006

Effective protection against experimental Taenia solium tapeworm infection in hamsters by primo-infection and by vaccination with recombinant or synthetic heterologous antigens.

The disease caused by Taenia solium is progressively being recognized as a growing global threat for public human health and pig husbandry that requires the development of effective control measures. A central participant in the taeniasis/cysticercosis transmission network is the human carrier of the adult tapeworm because of its great potential in spreading the infection. Herein, evidence is presented that a primary infection of golden hamsters with orally administered T. solium cysticerci improved the host's resistance against a secondary infection. Likewise, previous vaccination increased the hamster's resistance. Similar high levels of protection (> 78%) were induced by systemic or oral vaccination with the S3Pvac anticysticercosis synthetic peptide vaccine or the highly immunogenic recombinant chimera based on the protective peptide KETc1 bound to Brucella spp. lumazine synthase (BLS-KETc1). Increased resistance after primo-infection and vaccination possibly results from changes in the immune conditions prevailing in the host's intestine. The contribution to protection from the KETc1 and BLS epitopes in a chimeric vaccine is under study. Preventive vaccination of definitive hosts of T. solium against the tapeworm, the most relevant step in the taeniasis/cysticercosis transmission, may greatly impact the dynamics of endemic disease and has not been studied or tried previously.

Animals↗
PubMed2005

A novel synthetic adjuvant effectively enhances the immunogenicity of the influenza vaccine.

Influenza vaccination is a key intervention to reduce morbidity and mortality provoked by this disease. To date, the challenge of improving its efficacy remains unmet. The immunogenic synthetic peptide GK1 from Taenia crassiceps cysticerci was tested herein in its capacity as adjuvant, co-administered with the inactivated anti-influenza vaccine before and after challenge with influenza virus in both young and aged mice. Co-administration of GK1 with the influenza vaccine increased levels of anti-influenza antibodies in aged mice before and after infection, reduced the local inflammation that accompanied influenza vaccination itself and favored virus clearance after infection in both young and aged mice.

Adjuvants, Immunologic↗
PubMed2005

Improvement of the neighborhood based Levenberg-Marquardt algorithm by local adaptation of the learning coefficient.

In this letter, an improvement of the recently developed neighborhood-based Levenberg-Marquardt (NBLM) algorithm is proposed and tested for neural network (NN) training. The algorithm is modified by allowing local adaptation of a different learning coefficient for each neighborhood. This simple add-in to the NBLM training method significantly increases the efficiency of the training episodes carried out with small neighborhood sizes, thus, allowing important savings in memory occupation and computational time while obtaining better performance than the original Levenberg-Marquardt (LM) and NBLM methods.

Algorithms↗
PubMed2002

Bioavailability of ranitidine in healthy Mexican volunteers: effect of food.

Is well known that food can affect the bioavailability of several drugs, its impact is major for those drugs that have to act near of drug absorption. Documentation about alterations of ranitidine bioavailability by effect of food is poor. The purpose of this work was to evaluate the effect of food over the bioavailability of ranitidine. Twenty healthy Mexican volunteers were included for the study. The study was made in two stages, in the first one the volunteers had 12 hour fast and took a 300 mg of oral dose of ranitidine (without food, WOF) and blood samples were drawn. Two weeks later, the volunteers took a normal diet just before ranitidine intake (with food, WF). The area under the curve (AUC) was 30% greater in WOF, Cmax was 921.5 ng/ml (WF) vs. 1685.2 (WOF), and t1/2 was 2.70 +/- 1.38 (WF) h vs 3.66 +/- 1.34 (WOF). The AUC, Cmax and t1/2 were statistically different. It is evident that there are differences in the drug disposition due to the presence of food, then, it is possible that the efficacy of ranitidine as inhibitor of gastric secretion being limited by food.

Adolescent↗
PubMed2001

Synthetic peptide vaccine against Taenia solium pig cysticercosis: successful vaccination in a controlled field trial in rural Mexico.

Taenia solium cysticercosis seriously affects human health when localised in the central nervous system (CNS) and causes great economic loss in pig husbandry in rural areas of endemic countries. Increasing the resistance to the parasite in the obligatory host pig may help in curbing transmission. Three synthetic peptides based on protein sequences of the murine parasite Taenia crassiceps, which had previously been shown to induce protection in mice against homologous challenge, were tested as a vaccine against T. solium cysticercosis in pigs. Vaccinated and unvaccinated piglets (240 in all) were distributed in pairs among the peasants' households of two rural villages in Mexico in which 14% of the native pigs were cysticercotic. Ten to twelve months later, the effect of vaccination was evaluated at necropsy. Vaccination decreased the total number of T. solium cysticerci (98.7%) and reduced the prevalence (52.6%). The natural challenge conditions used in this field trial strengthen the likelihood of successful transmission control to both pig and human through a large-scale pig vaccination program. We believe this is a major contribution in anticysticercosis vaccine development as these rather simple yet protective peptides are potentially more cost-effective to produce and less variable in results than antigens that are more complex.

Amino Acid Sequence↗
PubMed2001

Two epitopes shared by Taenia crassiceps and Taenia solium confer protection against murine T. crassiceps cysticercosis along with a prominent T1 response.

Taenia crassiceps recombinant antigens KETc1 and KETc12 have been shown to induce high level of protection against experimental murine T. crassiceps cysticercosis, an experimental model successfully used to test candidate antigens for use in vaccination against porcine Taenia solium cysticercosis. Based on the deduced amino acid sequence, KETc1 and KETc12 were chemically synthesized in linear form. Immunization with KETc1 induced 66.7 to 100% protection against murine cysticercosis, and immunization with KETc12 induced 52.7 to 88.1% protection. The elicited immune response indicated that both peptides contain at least one B-cell epitope (as demonstrated by their ability to induce specific antibodies) and one T-cell epitope that strongly stimulated the proliferation of T cells primed with either the free peptide or total cysticercal T. crassiceps antigens. The high percentage of spleen cells expressing inflammatory cytokines points to the likelihood of a T1 response being involved in protection. The protective capacity of the peptides and their presence in all developmental stages of T. solium point to these two epitopes as strong candidates for inclusion in a polyepitopic synthetic vaccine against T. solium pig cysticercosis.

Animals↗
PubMed2001

Inhibitory role of antibodies in the development of Taenia solium and Taenia crassiceps toward reproductive and pathogenic stages.

Untreated Taenia solium cysticerci obtained from different naturally infected pigs vary notably in their capacity to develop into intestinal tapeworms in prednisolone-treated hamsters, whereas cells derived from Taenia crassiceps cysticerci after 2 mo of infection almost always develop to cysticerci in the peritoneal cavity of susceptible BALB/cAnN mice. Preincubation of whole cysticerci or parasite cells with mice immunoglobulins raised against an 18-mer peptide epitope (GK-1) common to both parasites significantly interferes with both transformations. These crippling effects of antiparasite antibodies suggest new forms of immunological interference with parasite biology other than simple killing. Antibodies that cripple biological functions of the parasite, e.g., their development to reproductive or pathogenic stages, make them important protagonists in taeniasis/cysticercosis disease as classic parasitocidal antibodies. Different serum levels of crippling antibodies in the infected pigs could be responsible for the varied ability of cysticerci to convert to tapeworms. Antigens capable of inducing crippling antibodies, e.g., GK-1, could be useful as a therapeutic vaccine for pigs in order to reduce parasite transmission.

Animals↗
PubMed2000

Prolongation of epidural anaesthesia in dogs with bupivacaine in a lipid emulsion.

An aqueous solution and a lipid emulsion of bupivacaine were administered epidurally in doses of 1.8 mg/kg to six beagle dogs following a randomised two-phase crossover design. The aqueous solution was absorbed rapidly and the mean (sd) peak venous plasma concentration of bupivacaine, 1.4 (0.4) microg/ml, was detected after five minutes. After administration of the lipid emulsion, the peak plasma concentration of bupivacaine, 0.6 (0.2) microg/ml, was detected after 30 minutes. The mean (sd) t1/2beta of the aqueous preparation was 149.1 (32.6) minutes, and of the lipid emulsion 119.2 (34.0) minutes. Both preparations had a similar bioavailability. The mean time to the onset of motor block after the administration of the aqueous solution, 2.3 (2.2) minutes, was significantly shorter (P=0.028) than after the administration of the lipid emulsion, 9.4 (1.9) minutes, and the duration of the motor block induced by the lipid emulsion, 217.6 (26.2) minutes, was significantly longer (P=0.043) than for the aqueous solution, 158 (48.8) minutes. During anaesthesia, the plasma concentrations of bupivacaine ranged between 1.3 and 0.2 microg/ml. Non-significant changes in systolic blood pressure and heart rate were observed which coincided with the peak plasma concentrations of bupivacaine.

Anesthesia, Epidural↗
PubMed2000

Taenia crassiceps cysticercosis: protective effect and immune response elicited by DNA immunization.

The nucleotide sequence of a protective recombinant antigen of Taenia crassiceps cysticerci present in all stages of Taenia solium (KETc7), cloned into pcDNA3 plasmid with the signal peptide sequence of the beta-glycan receptor (pTc-sp7), has been shown to be effective in protecting mice against experimental infection of T. crassiceps. To explore further the possibilities of this form of immunization and the immune response induced, mice were injected intramuscularly (i.m.) or intradermally (i.d.) with 3 doses of pTc-sp7. Similar levels of resistance were found using either i.m. or i.d. immunization. Spleen cells from i.d. and i.m. DNA immunized mice induced a specific T-cell response to T. crassiceps antigens and to a synthetic peptide from the immunogen itself (GK-1). Proliferated cells were especially enriched in CD8+ CD4- T-lymphocytes. A clear increase in the percentage of CD3+ cells that produce gamma-interferon and interleukin-2 was detected when measuring the intracellular cytokine production, an indication of the pTc-sp7 capacity to induce an effective cellular response. These results provide encouraging information on the use of KETc7 in the prevention of cysticercosis as well as a first insight into the characterization of the immune response induced by pTc-sp7 that hints to the relevance of cellular immunity in protection.

Animals↗
PubMed2000

[Fulminant streptococcus infection of soft tissue].

BACKGROUND: In recent years there has been an apparent increase in severe infections produced by group A beta-hemolytic Streptococci in developed countries. Necrotizing fascitis and myositis are two rare but fearsome complications caused by this microorganism. METHODS: Two cases of fulminant soft tissue infection recently observed in the authors' center are presented and the clinical presentation and differential diagnosis commented upon. RESULTS: The first case was a necrotizing fascitis at a surgical wound which appeared following a gynecological surgery. The second case reports gluteal myositis following intramuscular injection. In both cases the evolution was disastrous. CONCLUSIONS: Streptococcus pyogenes may produce fulminant infections in patients without underlying disease either spontaneously or following minimum traumas. The most frequent involvement is of the soft tissues. This virulence at a local tissue and systemic level has been associated with the production of exotoxin.

Diagnosis, Differential↗
PubMed1999

Chemical composition, digestibility and antinutritional factors content of two wild legumes: Styphonolobium burseroides and Acacia bilimekii.

The chemical composition, digestibility and toxin contents of two wild legumes: Styphnolobium burseroides and Acacia bilimekii, collected in a semi-arid zone of Mexico, were determined. Both legumes had a high fiber content. The seeds of Styphnolobium burseroides had a low protein content (14%), and the pod a high content of reducing sugars. However the seeds of Acacia bilimekii had a high protein concentration (35%). The seed proteins were low in sulphur amino acids and tryptophan in both legumes but were rich in lysine. Trypsin inhibitors and lectins were present in low concentrations; alkaloids and cyanogenic glucosides were not detected. The in vitro digestibility for monogastric animals was low but the same test with ruminal juice showed a high digestibility for both legumes. Based on their chemical composition and digestibility, these legumes could be a good alternative source in the feeding of ruminants.

Amino Acids↗
PubMed1999

Towards a Taenia solium cysticercosis vaccine: an epitope shared by Taenia crassiceps and Taenia solium protects mice against experimental cysticercosis.

The Taenia crassiceps recombinant antigen KETc7 has been shown to be effective as a vaccine against experimental murine cysticercosis, a laboratory model used to test potentially promising molecules against porcine Taenia solium cysticercosis. Based on the deduced amino acid sequence of this proline-rich polypeptide, three fragments, GK-1, GK-2, and GK-3, were chemically synthesized in linear form. Of the three peptides, only GK-1 induced sterile protection against T. crassiceps cysticercosis in 40 to 70% of BALB/cAnN male mice. GK-1 is an 18-amino-acid peptide which contains at least one B-cell epitope, as demonstrated by its ability to induce an antibody response to the peptide and T. crassiceps antigen without need of a carrier protein. Immunofluorescence studies revealed that anti-GK1 antibodies strongly react with the native protein in the tegument of T. crassiceps and also with anatomical structures of T. solium eggs, oncospheres, cysticercus, and tapeworm. GK-1 also contains at least one T-cell epitope, capable of stimulating the proliferation of CD8(+) and to a lower extent CD4(+) T cells primed either with the free peptide or T. crassiceps total antigen. The supernatant of the stimulated cells contained high levels of gamma interferon and low levels of interleukin-4. Similar results were obtained with T cells tested for intracellular cytokine production, an indication of the peptide's capacity to induce an inflammatory response. The remarkable protection induced by GK-1 immunization, its physicochemical properties, and its presence in all developmental stages of T. solium point to this synthetic peptide as a strong candidate in the construction of a synthetic vaccine against T. solium pig cysticercosis.

Amino Acid Sequence↗
PubMed1999

Pharmacokinetics and pharmacologic effects of the S(-) isomer of bupivacaine after intravenous and epidural administration in dogs.

OBJECTIVE: To determine pharmacokinetic variables and pharmacologic effects of the S(-) isomer of bupivacaine (S[-]-BPV) in dogs. ANIMALS: 6 adult male Beagles. PROCEDURE: Dogs received S(-)-BPV (1 mg/kg of body weight) i.v., and 15 days later, the same dogs received 1.8 mg/kg epidurally. Pharmacokinetic variables and pharmacologic effects were determined for each route of administration. RESULTS: After i.v. administration, plasma concentration versus time curves were adjusted, using biexponential equations that indicated a rapid distribution phase followed by a slower elimination phase, with a mean +/- SD half-life of 33.5 +/- 17.0 minutes. Mean plasma clearance was 21.0 +/- 10.7 ml/min/kg, and mean volume of distribution at steady state was 0.8 +/- 0.2 L/kg. After i.v. administration, mean peak plasma concentration was 2.6 +/- 0.7 micrograms/ml; after epidural administration, it was 0.9 +/- 0.5 microgram/ml at approximately 3 minutes. Half-life after epidural administration was 5 times longer than that observed after i.v. administration. Motor block began immediately after the end of epidural administration and lasted for 3 to 4 hours. Changes in systolic blood pressure and heart rate after epidural administration were slight but occurred at the same time that plasma concentration peaked. After i.v. administration, motor block or variations in physiologic variables studied were not observed. CONCLUSIONS AND CLINICAL RELEVANCE: In dogs, the pharmacologic behavior of S(-)-BPV was similar to that of the bupivacaine racemate, but motor block attributable to S(-)-BPV lasted longer than that attributable to the racemate, with lower plasma concentrations observed at equivalent sample collection times.

Anesthetics, Local↗