Search PubMed⌕ Search

Biomedical subjects

C Gonzalez

Publications and source records attributed to C Gonzalez.

At least 163 records · Page 9Linked to original sources
PubMed1994

Salmonella typhi vaccine strain CVD 908 expressing the circumsporozoite protein of Plasmodium falciparum: strain construction and safety and immunogenicity in humans.

rcsp, encoding amino acids 21-398 of Plasmodium falciparum circumsporozoite protein (CSP), under control of tacP was integrated into the chromosomal delta aroC locus of attenuated delta aroC, delta aroD Salmonella typhi CVD 908. By immunoblot and ELISA, rCSP expression was greater from a multicopy plasmid than from the single chromosomal gene. CVD 908 omega (delta aroC1019::tacP-rcsp) was well tolerated by 10 volunteers who were fed two doses of 5 x 10(7) organisms 8 days apart. Seven subjects excreted the vaccine strain for 1-3 days. All subjects developed serologic responses to O and H antigens of the live vector, whereas 3 vaccinees responded to the foreign antigen: 1 developed an 80-fold rise in serum anti-sporozoite antibody, another had a 4-fold rise in antibody to a recombinant portion of CSP (residues 309-345), while a third vaccinee developed CSP-specific CD8+ cytotoxic T lymphocyte activity. This is the first report of attenuated S. typhi eliciting a human serologic or a cytotoxic T lymphocyte response to a foreign protein. Improved foreign gene expression should enhance immunogenicity.

Administration, Oral↗
PubMed1994

Lactose maldigestion and milk intolerance: a study in rural and urban Mexico using physiological doses of milk.

Lactose digestion capacity after ingestion of physiological doses of milk and its effect on milk intolerance and consumption were studied in rural and urban populations from three regions of Mexico with different milk intakes. All subjects (n = 926) received two treatments: whole milk (240 mL for children and 360 mL for adults) and the same amount of 90% lactose-hydrolyzed milk; 72% of the subjects also received as a third treatment a water solution containing lactulose (8 g for children and 10 g for adults). Lactose maldigestion determined by a hydrogen breath test was detected in 2 to 43% of subjects (depending on age group) and was higher in subjects from central and southern Mexico than in subjects from northern Mexico (P < 0.01). Only the experience of major symptoms of intolerance affected milk consumption, and these symptoms were present in 0 to 11% of children > 4 y old and in 7 to 17% of the 13- to 60-y-old subjects. No significant differences were found in lactose maldigestion or milk intolerance between rural and urban populations, but milk consumption was higher in urban areas (P < 0.01). Milk consumption in our study was affected primarily by factors not related to the capacity to digest or tolerate the lactose in milk.

Adolescent↗
PubMed1994

Contrast media algogenic potential in peripheral arteriography. Potentiation of bradykinin-induced pain in the rat.

RATIONALE AND OBJECTIVES: Contrast media (CM) with minimal algogenic (pain causing) potential in animal models of peripheral arteriography are still able to produce vascular pain in humans; the poor predictive value of preclinical evaluation led us to develop a more sensitive method based on CM potentiation of bradykinin effects in the rat. METHODS: Behavioral pain responses and histologic alterations of the arteries were determined after intrafemoral injection of bradykinin to saline- or CM-pretreated rats. Pain reactions were compared with those elicited by single and repeated CM injections. RESULTS: Contrast media enhanced bradykinin-induced pain was dose dependent with the following potency order: iopamidol > iopromide > ZK 139129 > ZK 119095. Vasodilation and alterations of the arterial internal layer also were seen. Iopromide produced this sensitization at doses that did not elicit evident pain reactions per se. CONCLUSION: The method proved to be a highly sensitive preclinical discriminant of CM algogenic potential.

Angiography↗
PubMed1994

Molecular analysis of ribosomal DNA from the aphid Amphorophora idaei and an associated fungal organism.

The ribosomal DNA cistron from the large raspberry aphid, Amphorophora idaei (Hemiptera: Aphididae), has been mapped by restriction analysis. The results showed that the map of A. idaei was similar to those of the previously characterized aphids Schizaphis graminum and Acyrthosiphon pisum. An extra Bgl II site was found in some of the ribosomal DNA intergenic spacer repeats in A. idaei. Using in-situ hybridization to aphid mitotic chromosomes it was demonstrated that probes derived from this region mapped to the pair of X chromosomes and it was therefore aphid in origin. Polymerase chain reaction using conserved rDNA primers also detected significant amounts of a fungal genome in the DNA samples. Microscopic investigation showed that the external surface of A. idaei harboured fungal propagules, hyphae and yeast-like organisms.

Animals↗
PubMed1994

Salmonella-specific monoclonal antibodies against recombinant Salmonella typhi 36-kilodalton porin.

Mouse monoclonal antibodies were raised against recombinant Salmonella typhi 36-kDa porin monomer. Specificities of 16 monoclonal antibodies were analyzed as reactivity patterns in dot immunobinding and Western blot (immunoblot) assays using isolated outer membrane proteins of gram-negative bacteria and cloned purified S. typhi porin monomers and trimers. Four monoclonal antibodies were specific for Salmonella spp.

Animals↗
PubMed1994

Laryngocele associated with squamous carcinoma in a 20-year-old nonsmoker.

A laryngocele associated with squamous cell carcinoma of the larynx is reported in a 20-year-old man without a history of smoking. This is the youngest reported case of carcinoma associated with laryngocele in the literature. This association is supported by the patient's young age and his nonsmoking status. However, this case does not appear to support the conclusion that laryngoceles predispose to the development of squamous cell carcinoma. The clinical history supports the tumor obstruction theory, whereby a laryngocele developed from an obstructing carcinoma of the ventricle.

Adult↗
PubMed1994

Treatment of vaginal agenesis with vulvoperineal fasciocutaneous flaps.

A simple surgical technique is reported for the treatment of vaginal agenesis utilizing vulvoperineal fasciocutaneous flaps based on the terminal vessels of the internal pudendal artery. Two vulvoperineal axial flaps are sutured together, skin surface opposed, then rotated posteriorly into rectovesical space. The operation has been performed on one patient, with good anatomic and functional results and without complications.

Adult↗
PubMed1993

Antisense oligodeoxynucleotides: synthesis, biophysical and biological evaluation of oligodeoxynucleotides containing modified pyrimidines.

6-Azathymidine, 6-aza-2'-deoxycytidine, 6-methyl-2'-deoxyuridine, and 5,6-dimethyl-2'-deoxyuridine nucleosides have been converted to phosphoramidite synthons and incorporated into oligodeoxynucleotides (ODNs). ODNs containing from 1 to 5 of these modified pyrimidines were compared with known 2'-deoxyuridine, 5-iodo-2'-deoxyuridine, 5-bromo-2'-deoxyuridine, 5-fluoro-2'-deoxyuridine, 5-bromo-2'-deoxycytidine, and 5-methyl-2'-deoxycytidine nucleoside modifications. Stability in 10% heat inactivated fetal calf serum, binding affinities to RNA and DNA complements, and ability to support RNase H degradation of targeted RNA in DNA-RNA heteroduplexes were measured to determine structure-activity relationships. 6-Azathymidine capped ODNs show an enhanced stability in serum (7- to 12-fold increase over unmodified ODN) while maintaining hybridization properties similar to the unmodified ODNs. A 22-mer ODN having its eight thymine bases replaced by eight 6-azathymines or 5-bromouracils hybridized to a target RNA and did not inhibit RNase H mediated degradation.

Base Sequence↗
PubMed1993

Evaluation of 2'-modified oligonucleotides containing 2'-deoxy gaps as antisense inhibitors of gene expression.

We have used a previously described 17-mer phosphorothioate (Monia, B.P., Johnston, J.F., Ecker, D. J., Zounes, M.A., Lima, W.F., and Freier, S.M. (1992) J. Biol. Chem. 267, 19954-19962) for structure-function analysis of 2'-sugar modifications including 2'-O-methyl, 2'-O-propyl, 2'-O-pentyl, and 2'-fluoro. These modifications were analyzed for hybridization affinity to complementary RNA and for antisense activity against the Ha-ras oncogene in cells using a highly sensitive transactivation reporter gene system. Hybridization analysis demonstrated that all of the 2'-modified oligonucleotides hybridized with greater affinity to RNA than an unmodified 2'-deoxy oligonucleotide with the rank order of affinity being 2'-fluoro > 2'-O-methyl > 2'-O-propyl > 2'-O-pentyl > 2'-deoxy. Evaluation of antisense activities of uniformly 2'-modified oligonucleotides revealed that these compounds were completely ineffective in inhibiting Ha-ras gene expression. Activity was restored if the compound contained a stretch of at least five 2'-deoxy residues. This minimum deoxy length correlated perfectly with the minimum length required for efficient RNase H activation in vitro using partially purified mammalian RNase H enzyme. These chimeric 2'-modified/deoxy phosphorothioates displayed greater antisense potencies in inhibiting Ha-ras gene expression, compared with the unmodified uniform deoxy phosphorothioate. Furthermore, antisense potency correlated directly with affinity of a given 2' modification for it's complementary RNA. These results demonstrate the importance of target affinity in the action of antisense oligonucleotides and of RNase H as a mechanism by which these compounds exert their effects.

Base Composition↗
PubMed1993

Uniformly modified 2'-deoxy-2'-fluoro phosphorothioate oligonucleotides as nuclease-resistant antisense compounds with high affinity and specificity for RNA targets.

"Uniformly" modified phosphodiester or phosphorothioate oligonucleotides incorporating 2'-deoxy-2'-fluoroadenosine, -guanosine, -uridine, and -cytidine, reported herein for the first time, when hybridized with RNA afforded consistent additive enhancement of duplex stability without compromising base-pair specificity. CD spectra of the 2'-deoxy-2'-fluoro-modified oligonucleotides hybridized with RNA indicated that the duplex adopts a fully A-form conformation. The 2'-deoxy-2'-fluoro-modified oligonucleotides in phosphodiester form were not resistant to nucleases; however, the modified phosphorothioate oligonucleotides were highly nuclease resistant and retained exceptional binding affinity to the RNA targets. The stabilizing effects of the 2'-deoxy-2'-fluoro modifications on RNA-DNA duplexes were shown to be superior to those of the 2'-O-methylribo substitutions. RNA hybrid duplexes with uniformly 2'-deoxy-2'-fluoro-modified oligonucleotides did not support HeLa RNase H activity; however, incorporation of the modifications into "chimeric" oligonucleotides has been shown to activate mammalian RNase H. "Uniformly" modified 2'-deoxy-2'-fluoro phosphorothioate oligonucleotides afforded antisense molecules with (1) high binding affinity and selectivity for the RNA target and (2) stability toward nucleases.

Base Sequence↗
PubMed1993

CD and 1H-NMR studies on the conformational properties of peptide fragments from the C-terminal domain of thermolysin.

The propensity of the peptide fragments 233-248, 245-260, 258-276, 279-298 and 299-316 from the thermolysin C-terminal domain to form non-random structures has been examined by CD and two-dimensional NMR spectroscopy. The conformational properties of these fragments have been studied in aqueous solution and in the mixed solvent trifluoroethanol/H2O (3:7 by vol.). Small but detectable populations of helical structures (up to 10-20%) in aqueous solution have been found for the fragments 233-248, 279-298 and 299-316. These populations are remarkably enhanced (50-70%) in the more hydrophobic mixed solvent, where the fragment 258-276 also forms a comparable helical population. These four fragments are helical in the native crystal structure and the spanning of the corresponding helices in the isolated peptides in solution matches very closely the ones in the native structure. In contrast, the fragment 245-260, an omega-loop in the crystal, remains unstructured in both solvents. Medium-range NOE between protons in sidechains indicate the adoption of preferred sidechain conformations accompanying helix formation. Results are in agreement with the framework model of folding, in which native elements of secondary structure are formed first and folding follows from the collapse of these structural elements.

Amino Acid Sequence↗
PubMed1993

Computer assisted CT-guided stereotactic transplantation of foetal ventral mesencephalon to the caudate nucleus and putamen in Parkinson's disease.

We report our preliminary results related to CT-guided stereotactic transplantation of foetal ventral mesencephalic cell suspension into the striatum of five patients with idiopathic Parkinson's disease. The mean age was 51 years, the evolution time of the disease ranged from 7 to 14 years, and all of them had motor complications associated with chronic L-dopa therapy. The patients were evaluated according to the Core Assessment Program for Intracerebral Transplantations (CAPIT) for one year before and three months after surgery. The postoperative clinical assessment demonstrated significant improvement of neurological symptoms and reduction of daily L-dopa dosage.

Caudate Nucleus↗
PubMed1993

Lipopolysaccharide-independent radioimmunoprecipitation and identification of structural and in vivo induced immunogenic surface proteins of Salmonella typhi in typhoid fever.

The humoral response to Salmonella typhi is important for protective immunity against typhoid fever, as indicated by the protection obtained with killed cell vaccines and component vaccines (outer membrane proteins, Vi antigen) in animals and human beings. Nonetheless, analysis and interpretation of host humoral immune response to S. typhi surface antigens have been difficult because of the complex structure of the S. typhi envelope and the lack of purified reagents for detection of immune response to individual surface components. Normal and convalescent human sera from typhoid fever patients were absorbed with S. typhi lipopolysaccharide. These sera were used in radioimmunoprecipitation assays of whole S. typhi cells and S. typhi membranes labelled with either 125I or 35S-methionine. This strategy has permitted the unequivocal identification of a humoral immune response to structural and in vivo induced outer membrane proteins of S. typhi. In this manner, we have identified the porins, lipoprotein, the iron-starvation-induced proteins, and three proteins of 30, 18.5 and 15 kDa as surface-exposed immunogens of S. typhi in patients with typhoid fever. These studies suggest that further experimental work is needed to characterize the relevance of both anti-S. typhi outer membrane protein and antilipopolysaccharide antibodies in recovery from S. typhi infections and protective immunity.

Antibodies, Bacterial↗
PubMed1993

The cultural construction of childhood diarrhoea in rural Nicaragua: relevance for epidemiology and health promotion.

As a component of a series of studies of childhood diarrhoea in rural Nicaragua, lay knowledge regarding the condition and its appropriate management has been investigated through semistructured interviews with 70 mothers. These data have been combined with information from focus group discussions and observations from investigators who have been resident in the study area for many years. For any episode of childhood diarrhoea, the lay nosology influences the treatment path followed. Thus for some types of diarrhoea, treatment at a health centre or health post and the use of rehydration fluids is seen to be appropriate, while for other types the use of traditional healers or home-based treatment, often explicitly without the use of rehydration fluids, is applicable. The implications of lay nosological systems for the interpretation of epidemiological studies and for the implementation of health promotion programmes are discussed.

Adolescent↗
PubMed1993

Performance of semiquantitative food frequency questionnaires in international comparisons. Mexico City versus San Antonio, Texas.

International dietary comparisons present a number of methodologic difficulties. We developed two semiquantitative food frequency questionnaires for use in Mexico City and San Antonio, Texas. The Mexico City questionnaire contained 85 food items and the San Antonio questionnaire contained 108. Thirty-six items were common to both questionnaires. The questionnaires were administered to 128 Mexican Americans, 35 to 64 years old, residing in a low-income barrio neighborhood of San Antonio and to 644 similarly aged Mexicans residing in a low-income "colonia" of Mexico City. Major differences in fat and carbohydrate intake as a percent of total kilocalories were observed between the two study groups, with Mexico City residents consuming approximately 18 to 21% of calories from fat and 68 to 72% from carbohydrate compared to 29 to 33% from fat and 48 to 52% from carbohydrate for Mexican Americans from San Antonio. Both of these differences were highly statistically significant (P < 0.001). A number of arguments support the validity of these findings. First, the distribution of high- and low-fat foods was similar on both questionnaires. Also, of the top-ten foods (as contributors to total kilocalorie intake) in San Antonio, seven were high in fat (> 30% of kilocalories), whereas this was true of only three of the top-ten foods in Mexico City.

Adult↗
PubMed1993

The centrosome.

Explore the source record for details and available documents.

Animals↗
PubMed1993

Distribution of mast cells and the effect of their mediators on contractility in human myometrium.

OBJECTIVE: To examine the distribution of mast cells in human uterine tissue and to study the interactions between mast cell mediators (histamine and serotonin) and PGF2 alpha in human myometrium contractile activity. DESIGN: Distribution of mast cells were analysed in cryostat sections of myometrium samples stained with Toluidine blue. Contractile activity was evaluated in an isolated organ bath preparation on myometrial strips obtained from women whose pregnancies ended in elective caesarean section. SETTING: Biological Science Laboratories at the University of Concepción. SUBJECTS: Twenty women undergoing elective caesarean and 10 women undergoing hysterectomy at the G. Grant Hospital. MAIN OUTCOME MEASUREMENTS: Cumulative concentration-response curves for histamine and serotonin before and after the addition of subumbral concentrations of the PGF2 alpha or serotonin were performed. RESULTS: Serotonin was more active than histamine to evoke contractions (EC50:0.20 (SE 0.02) mumol/l vs 1.5 (SE 0.2) mumol/l, respectively). Furthermore, threshold concentrations of serotonin (0.05 mumol/l) potentiated the contractile effect of histamine (EC50:0.3 (SE 0.06) mumol/l and 50% increase in E(max)). PGF2 alpha had a poor contractile effect, but threshold concentrations (0.05 and 0.10 mumol/l) enhanced the contractile effect of both serotonin and histamine. A population of mast cells was found in close apposition to smooth muscle fibres. CONCLUSIONS: It is postulated that the simultaneous release of mast cell mediators (histamine and serotonin) in myometrium could be an important stimulus for evoking strong contractions in the human uterus. PGF2 alpha may have indirect effects in myometrium by amplifying the effects of histamine and serotonin.

Dinoprost↗