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Biomedical subjects

G Seoane

Publications and source records attributed to G Seoane.

18 recordsLinked to original sources
PubMed2003

Maternal and congenital syphilis in Bolivia, 1996: prevalence and risk factors.

OBJECTIVES: The present study was carried out in seven maternity hospitals to determine the prevalence of maternal syphilis at the time of delivery and the associated risk factors, to conduct a pilot project of rapid syphilis testing in hospital laboratories, to assure the quality of syphilis testing, and to determine the rate of congenital syphilis in infants born to women with syphilis at the time of delivery--all of which would provide baseline data for a national prevention programme in Bolivia. METHODS: All women delivering either live-born or stillborn infants in the seven participating hospitals in and around La Paz, El Alto, and Cochabamba between June and November 1996 were eligible for enrolment in the study. FINDINGS: A total of 61 out of 1428 mothers (4.3%) of live-born infants and 11 out of 43 mothers (26%) of stillborn infants were found to have syphilis at delivery. Multivariate analysis showed that women with live-born infants who had less than secondary-level education, who did not watch television during the week before delivery (this was used as an indicator of socioeconomic status), who had a previous history of syphilis, or who had more than one partner during the pregnancy were at increased risk of syphilis. While 76% of the study population had received prenatal care, only 17% had syphilis testing carried out during the pregnancy; 91% of serum samples that were reactive to rapid plasma reagin (RPR) tests were also reactive to fluorescent treponemal antibody-absorption (FTA-ABS) testing. There was 96% agreement between the results from local hospital laboratories and national reference laboratories in their testing of RPR reactivity of serum samples. Congenital syphilis infection was confirmed by laboratory tests in 15% of 66 infants born to women with positive RPR and FTA-ABS testing. CONCLUSION: These results indicate that a congenital syphilis prevention programme in Bolivia could substantially reduce adverse infant outcomes due to this disease.

Analysis of Variance↗
PubMed2001

Nematocidal activity of natural polyphenols from bryophytes and their derivatives.

The nematocidal in vitro activity of three natural perotetins (phenolic bisbibenzyiethers) and eleven diphenyl ethers used as synthetic precursors has been assayed using two different experimental models, Caenorhabditis elegans and Nippostrongylus brasiliensis. Nine compounds showed some activity against C. elegans and nine against N. brasiliensis. For the former model, three compounds displayed an activity similar to that of the standards, whereas for N. brasiliensis none of the tested compounds was as active as the standards. From the in vitro results, five compounds (3, 4, 8, 9, 13) could be selected as lead compounds to continue the search for improved activity.

Animals↗
PubMed2001

New thiadiazine derivatives with activity against Trypanosoma cruzi amastigotes.

The cytotoxicity of 18 new 1,2,6-thiadiazin-3,5-dione 1,1-dioxides was evaluated. This group of products was previously assayed against epimastigotes of Trypanosoma cruzi and some of them showed a high antiprotozoal activity. Thereafter 13 compounds with a high anti-epimastigote activity and low cytotoxicity were selected to be assayed against amastigotes. Some of the products showed the same or even lower cytotoxicity than nifurtimox and benznidazole, but most of them were very toxic for macrophages at 100 microg/ml. Only one of the compounds had an anti-amastigote activity similar to that of reference drugs at 10 microg/ml, but unfortunately this disappeared at lower concentrations.

Animals↗
PubMed2000

Synthesis and biological evaluation of 1,2,5-oxadiazole N-oxide derivatives as potential hypoxic cytotoxins and DNA-binders.

Several new 1,2,5-oxadiazole N-oxide derivatives were synthesized to be tested both as potential selective hypoxic cell cytotoxins and as DNA-binding agents. The compounds prepared included bis(1,2,5-oxadiazole N-oxide) derivatives and oxadiazole rings linked to naphthyl residues. The compounds were tested for their cytotoxicity in oxia and hypoxia and they proved to be non-selective and less active than the parent compounds 3-formyl-4-phenyl-1,2,5-oxadiazole N2-oxide (3) and 3-chloromethyl-4-phenyl-1,2,5-oxadiazole N2-oxide (4). The DNA-affinity assays showed that the compounds tested have poor affinity for this biomolecule.

Aerobiosis↗
PubMed2000

Synthesis and antitrypanosomal evaluation of E-isomers of 5-nitro-2-furaldehyde and 5-nitrothiophene-2-carboxaldehyde semicarbazone derivatives. structure-activity relationships.

Several novel semicarbazone derivatives were prepared from 5-nitro-2-furaldehyde or 5-nitrothiophene-2-carboxaldehyde and semicarbazides bearing a spermidine-mimetic moiety. All derivatives presented the E-configuration, as determined by NMR-NOE experiments. These compounds were tested in vitro as potential antitrypanosomal agents, and some of them, together with the parent compounds, 5-nitro-2-furaldehyde and 5-nitrothiophene-2-carboxaldehyde semicarbazone derivatives, were also evaluated in vivo using infected mice. Structure-activity relationship studies were carried out using voltammetric response and lipophilic-hydrophilic balance as parameters. Two of the compounds (1 and 3) displayed the highest in vivo activity. A correlation was found between lipophilic-hydrophilic properties and trypanocidal activity, high R(M) values being associated with low in vivo effects.

Aldehydes↗
PubMed2000

Synthesis and herbicidal activity of N-oxide derivatives.

As part of an ongoing program on the chemistry and biological activity of N-oxide-containing molecules, a number of novel 1,2, 5-oxadiazole N-oxide, benzo[1,2-c]1,2,5-oxadiazole N-oxide, and quinoxaline N,N'-dioxide derivatives were synthesized and evaluated for their herbicidal activity. Many of these compounds exhibited moderate to good herbicidal pre-emergence activity against Triticum aestivum. Dose-response studies were done on the more representative compounds (12, 20, and 26). The most active compound, butylcarbamoylbenzo[1,2-c]1,2,5-oxadiazole N-oxide, 26, displayed herbicidal activity at concentrations as low as 24 g/ha.

Dose-Response Relationship, Drug↗
PubMed2000

(S)-tricarbonyl

Explore the source record for details and available documents.

Journal Article↗
PubMed2000

Marchantin M trimethyl ether.

The title macrocycle, C(31)H(30)O(5), is comprised of two bibenzyl ether moieties linked cyclically by spacers which each consist of two-carbon alkyl chains. The observed conformation of the macrocycle may be partly stabilized by intramolecular C-H.O close contacts. The packing appears to be directed by van der Waals forces. This work explains the occurrence of a signal found in the (1)H NMR spectra of both marchantinquinone and marchantin M trimethyl ether at delta = 5. 49 and 5.56 p.p.m., respectively. The shift in the position of the expected peak can be explained by the proximity of an H atom belonging to one of the aromatic rings to another ring in the same molecule.

Journal Article↗
PubMed2000

Applicability of the Asthma Opinion Survey in the Spanish population: distribution and relationship with sociodemographic and clinical variables.

We evaluated a Spanish version of the Asthma Opinion Survey (AOS) in a sample of 90 adult Spanish asthma patients. The Spanish AOS showed acceptable internal consistency, and a factorial structure similar to that reported by others, i.e., vulnerability, perceived quality of care, and recognition and control, although we additional ly obtained a fourth factor, attitudes toward patient knowledge. Vulnerability was significantly higher among older patients, and among patients with lower educational level, lower income, and more severe asthma. Perceived quality of care, and recognition and control were positively correlated with frequency of attacks, and recognition and control was significantly higher in older patients. The factor attitudes toward patient knowledge was significantly higher in younger patients and in patients with relatively high income. These results support the cross-cultural validity of this questionnaire.

Adolescent↗
PubMed1999

1,2,5-Oxadiazole N-oxide derivatives and related compounds as potential antitrypanosomal drugs: structure-activity relationships.

The syntheses of a new series of derivatives of 1,2,5-oxadiazole N-oxide, benzo[1,2-c]1,2,5-oxadiazole N-oxide, and quinoxaline di-N-oxide are described. In vitro antitrypanosomal activity of these compounds was tested against epimastigote forms of Trypanosoma cruzi. For the most effective drugs, derivatives IIIe and IIIf, the 50% inhibitory dose (ID50) was determined as well as their cytotoxicity against mammalian fibroblasts. Electrochemical studies and ESR spectroscopy show that the highest activities observed are associated with the facile monoelectronation of the N-oxide moiety. Lipophilic-hydrophilic balance of the compounds could also play an important role in their effectiveness as antichagasic drugs.

Animals↗
PubMed1999

The importance of pragmatic aspects in conditional reasoning.

The importance of pragmatic aspects in conditional reasoning was assessed in the performance of 54 subjects (26 female and 28 male; mean age 17.6 years) on 48 conditional inference problems, using a 3 x 2 x 4 design, with repeated measurements. The independent variables were probability of empirical frequency in the real world, type of conditional rule, and scenario availability. Number of correct responses and subjects' certainty about the correctness of their responses were the dependent variables. The results showed: a) the scenario availability is not sufficient in itself to explain differences in performance, but it does affect the subjects' degree of confidence in their conclusions; b) there is an interaction between probability of empirical frequency in the real world and type of conditional rule on correct performance. The results were contrasted with the predictions made by the mental models theory and its revised version proposed by Evans (1993). These findings support the semantic theories of conditional reasoning.

Adolescent↗
PubMed1999

Synthesis and antichagasic properties of new 1,2,6-thiadiazin-3,5-dione 1,1-dioxides and related compounds.

In a search for antichagasic drugs, 14 new 4-(nitroarylidene)-1,2,6-thiadiazin-3,5-dione 1,1-dioxide derivatives were synthesized and tested in vitro against the epimastigote form of Trypanosoma cruzi and some of them showed important antiprotozoan activity. Attempts to synthesize new 4-(nitroarylidene)-3,5-diamino-1,2,6-thiadiazine 1,1-dioxides were unsuccessful. The antichagasic properties of nitroarylidene-malononitrile and nitroarylidene-cyanoacetamide derivatives, thus obtained, were also tested. The cytotoxic properties against Vero cells of compounds which showed remarkable in vitro antichagasic activity were evaluated. All compounds tested exhibited high toxicity percentages at 100 micrograms/ml. However, compound 3c showed in vitro antichagasic and cytotoxic properties such as nifurtimox at the dose of 10 micrograms/ml.

Animals↗
PubMed1998

Synthesis and anti-trypanosomal activity of novel 5-nitro-2-furaldehyde and 5-nitrothiophene-2-carboxaldehyde semicarbazone derivatives.

Several novel semicarbazones derivatives were prepared from 5-nitro-2-furaldehyde or 5-nitrothiophene-2-carboxaldehyde, and tested in vitro as potential anti-trypanosomal agents. The compounds were prepared in good to excellent yields in 2-3 steps from readily available starting materials. Some derivatives were found to be active against Trypanosoma cruzi with an activity similar to that of Nifurtimox.

Animals↗
PubMed1998

Impact of community organization of women on perinatal outcomes in rural Bolivia.

An intervention to improve maternal and child health was conducted in a remote Bolivian province with limited access to modern medical facilities. The intervention focused on initiating and strengthening women's organizations, developing women's skills in problem identification and prioritization, and training community members in safe birthing techniques. Its impact was evaluated by comparing perinatal mortality rates and obstetric behavior among 409 women before and after the intervention. Perinatal mortality decreased from 117 deaths per 1,000 births before the intervention to 43.8 deaths per 1,000 births after. There was a significant increase in the number of women participating in women's organizations following the intervention, as well as in the number of organizations. The proportion of women receiving prenatal care and initiating breast-feeding on the first day after birth was also significantly larger. The number of infants attended to immediately after delivery likewise increased, but the change was not statistically significant. This study demonstrates that community organization can improve maternal and child health in remote areas.

Adolescent↗
PubMed1996

[Presence in Cuba of screw worms (Cochliomyia hominivorax) in the livestock].

Screw-worms (Cochliomyia hominivorax Coquerel) constitute a serious plight for livestock in the New World, because they inflict high losses on animals and man. A survey was done by means of an epizootic surveillance system with geographic squares to check for the presence of the insects in Cuba. Screw-worms were detected in 54.8% of myiasis cases all over the island, affecting various animals species, cattle first, followed by swine, sheep and others. Small injuries appeared to be the main enabling factor for screw-worm development. The reasons for the presence of screw-worms without serious consequences on the Cuban livestock are discussed.

Animals↗
PubMed1992

Formal potentials of new analogues of nifurtimox: relationship to activity.

Electrochemical studies (Formal Potentials and Coulometry) were performed on several analogues of Nifurtimox, in order to gain insight on the proposed mechanism of action of these drugs. It is thought that Nifurtimox shows part of its trypanocidal activity via an electron transfer process, leading to the production of active oxygen species that kill the parasite. Formal potentials provide relevant data about the feasibility of electron transfer in vivo. All analogues tested contained the nitro group, which is the most easily reducible group in the parent drug Nifurtimox. The formal potentials values determined ranged from -1.86 to -0.46 V. Coulometric runs were carried out to study the one-electron transfer process. A good correlation between formal potentials and biological activity was found.

Animals↗
PubMedDate not supplied

General method of synthesis for natural long-chain beta-diketones.

Two general methods of synthesis have been developed for the preparation of long-chain beta-diketones. The first relies on malonate-type alkylation of acid chlorides derived from fatty acids, while the second, more direct method, involves coupling and subsequent hydrolysis of long-chain acetylenes with acid chlorides of fatty acids.

Alkylation↗