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Biomedical subjects

L Gomez

Publications and source records attributed to L Gomez.

At least 73 records · Page 4Linked to original sources
PubMed1993

Field trial of vaccination against American trypanosomiasis (Chagas' disease) in dogs.

In Santiago del Estero, an area endemic for Chagas' disease in northwestern Argentina, household dogs were vaccinated with live-attenuated Trypanosoma cruzi, and the prospective incidence of natural infection by this parasite was assessed during a two-year followup period. Vaccinated dogs received 10(7) attenuated, TCC strain T. cruzi epimastigotes and were given booster vaccinations two and 14 months later. The number of animals that could be evaluated in vaccinated versus control groups was 73 and 75 after one year and 49 and 40 after two years, respectively. Parasitologic evaluation by xenodiagnosis indicated that vaccination had reduced natural T. cruzi infection from 26.7% to 12.3% after one year (P = 0.015). The preventive effect of vaccination after the second year was less significant in spite of the booster vaccinations. Inclusion of indirect hemagglutination data for the diagnosis of infection slightly increased the number of infected dogs without affecting the evidence for protection in the first year. Serologic, parasitologic, and isoenzyme studies indicated that protection was mediated by an attenuated, self-cured infection. In 15 dogs in which the vaccination failed to completely prevent natural infection, immunization nevertheless impaired their ability to infect the natural insect vectors of the disease in humans.

Agglutination Tests↗
PubMed1992

Wheat and barley allergens associated with baker's asthma. Glycosylated subunits of the alpha-amylase-inhibitor family have enhanced IgE-binding capacity.

A 16 kDa protein, designated CM16*, which strongly binds IgE from baker's-asthma patients has been identified as a glycosylated form of the previously reported WTAI-CM16, which is a subunit of the wheat tetrameric alpha-amylase inhibitor. A glycosylated form (CMb*) of BTAI-CMb, the equivalent inhibitor subunit from barley, has been also found to have significantly enhanced IgE-binding capacity. In all, 14 purified members of the alpha-amylase/trypsin-inhibitor family showed very different IgE-binding capacities when tested by a dot-blot assay. The glycosylated components CM16*, CMb* and the previously described non-glycosylated 14.5 kDa allergen from barley (renamed BMAI-1) were found to be the strongest allergens.

Allergens↗
PubMed1992

A major barley allergen associated with baker's asthma disease is a glycosylated monomeric inhibitor of insect alpha-amylase: cDNA cloning and chromosomal location of the gene.

A 14.5 kDa barley endosperm protein that is a major allergen in baker's asthma disease, as previously shown by both in vitro (IgE binding) and in vivo tests, has been identified as a glycosylated monomeric member of the multigene family of inhibitors of alpha-amylase/trypsin from cereals. A cDNA encoding this allergen (renamed BMAI-1) has been isolated and characterized. The deduced sequence for the mature protein, which is 132 residues long, is identical in its N-terminal end to the 20 amino acid partial sequence previously determined from the purified allergen, and fully confirms that it is a member of the multigene family of cereal inhibitors. Southern-blot analysis of wheat/barley addition lines using the insert in the BMAI-1 cDNA clone as a probe, has led to the location of the allergen gene (Iam1) in barley chromosome 2, while another related member of this protein family, the barley dimeric alpha-amylase inhibitor BDAI-1 gene (Iad1) has been located in chromosome 6. Iam1 is the first member of this inhibitor family in cereals to be assigned to chromosome group 2, thus extending the dispersion of genes in the family to five out of the seven homology groups of chromosomes in wheat and barley (chromosomes 2, 3, 4, 6 and 7).

Air Pollutants, Occupational↗
PubMed1992

Kinetics of particulate and solute marker passage in sheep supplemented with cationomycin and lasalocid antibiotics. Comparisons among methods for calculating mean retention time.

Passage of particulate and solute markers in the digestive tract was studied in sheep fed a roughage-pelleted diet supplemented or not with ionophore antibiotics. Methods of marker administration (continuous infusion vs pulse-dose) and mathematical treatment of data were investigated. Antibiotic supplementation did not affect markers' mean retention time (MRT) significantly, regardless of sampling site, technique of marker administration or MRT calculation methods used. The pulse dose technique led to 20-30% higher estimate of particle markers MRT in the entire gut and stomachs of sheep than did the continuous infusion method. Similar results were obtained between these methods for solute markers MRT at both sampling sites. Total MRT in the digestive tract could be partitioned among compartments using a deterministic model when applied to pulse-dose kinetics. Such a partitioning appeared unsatisfactory with continuous-infusion data. Estimations of particle or solute markers MRT in the rumen from duodenal and faecal marker kinetics were significantly different and rarely correlated.

Animal Feed↗
PubMed1992

Adenocarcinoma of the ethmoid olfactory mucosa: a histopathological and ultrastructural study with evidence of virus-like particles.

A histopathological, morphometric and ultrastructural study was made of enzootic nasal neoplasia in a group of 25 Verata goats. A nasal adenocarcinoma was diagnosed. The neoplasm contained two clearly defined zones, one cystic and the other compact. The tumour stroma was composed of abundant loose connective tissue, in which mononuclear infiltrate was clearly identifiable. The observed viral particles were morphologically similar to Visna-Maedi. These particles had an eccentrically located electrodense core. The diameter of the virus was about 90 nm and it showed envelope numerous spikes on the surface. The virus is assumed to be the causative primary agent of the tumour.

Adenocarcinoma↗
PubMed1991

Wheat Inhibitors of Heterologous alpha-Amylases : Characterization of Major Components from the Monomeric Class.

The four major components of the wheat monomeric alpha-amylase inhibitors (WMAI) from wheat, Triticum aestivum, endosperm have been isolated and characterized. Two of them, WMAI-1 and WMAI-2, are highly active against the alpha-amylase from the insect Tenebrio molitor and their N-terminal amino acid sequences indicate that they are closely related to each other (86% identical residues) and to the other members of the family (subunits of dimeric and tetrameric alpha-amylase inhibitors and trypsin inhibitors). WMAI-1, which is identical to the previously described 0.28 inhibitor, is encoded by a gene located in the short arm of chromosome 6D and WMAI-2 by a gene in the short arm of chromosome 6B. Components 3 and 4, which have blocked N-terminal residues, have identical internal amino acid sequences and are a separate class of proteins with respect to WMAI-1 and WMAI-2, although their amino acid composition and apparent molecular weights are quite similar. Their inhibitory activity versus alpha-amylases is either unstable during the purification process or due to contamination with other inhibitors.

Journal Article↗
PubMed1990

In vitro study (Rusitec) of the action of abierixin, a new ionophore antibiotic, on the end products of fermentation and the degradation of nitrogen in the rumen.

We investigated the capacity of a new ionophore antibiotic, abierixin, to modify fermentations in the rumen using a semi-continuous fermenter (Rusitec). As in the studies carried out on a "batch" fermenter (HILLAIRE et al., 1989a), abierixin failed to alter volatile fatty acids and gas productions but, in contrast, it limited the degradation of dietary nitrogen without affecting microbial synthesis. This molecule which has a low level of toxicity and is capable of improving the use of dietary proteins by ruminants, was found to be more effective when used at very low dose levels.

Animals↗
PubMed1989

New dimeric inhibitor of heterologous alpha-amylases encoded by a duplicated gene in the short arm of chromosome 3B of wheat (Triticum aestivum L.).

A new wheat dimeric alpha-amylase inhibitor, designated WDAI-3, has been characterized. WDAI-3 is a homodimeric protein active against alpha-amylase from human saliva and from the insect Tenebrio molitor, but inactive against that from pig pancreas or against trypsin. Its N-terminal amino acid sequence is closer to those of the wheat dimeric inhibitors 0.19 and 0.53 (89-91% identical positions in 44 residues) than to that of the monomeric 0.28 inhibitor (69% identical positions). Iha-B1-2, the gene encoding the new inhibitor, is located in the short arm of chromosome 3B, where it is part of an intrachromosomal gene duplication that also codes for the 0.53 inhibitor.

Amino Acid Sequence↗
PubMed1989

Importance of hereditary disease at a Neuropsychiatric Institute in Mexico City.

The objective of this study is to investigate the type, importance, and incidence of hereditary diseases in patients at the National Institute of Neurology and Neurosurgery in Mexico City. A review of 6,258 files indicated that hereditary diseases represent an important problem for the Institute. Of the diseases with the highest incidences, hereditary factors have an important role in seven (epilepsy, depression, facial palsy, schizophrenia, mental retardation, migraine, and Parkinson's disease). Diseases of known monogenic etiology represent 1.5% of all the cases.

Adolescent↗
PubMed1989

Wheat tetrameric inhibitors of insect alpha-amylases: Alloploid heterosis at the molecular level.

Tetrameric inhibitors of heterologous alpha-amylases have been characterized in allohexaploid wheat, Triticum aestivum (genomes AABBDD), as well as in Triticum turgidum (AABB) and Triticum tauschii (DD). Their subunits have been identified as the previously described CM proteins. Single oligomeric species were observed in T. Turgidum (subunits CM2, CM3A, and CM16) and in T. tauschii (CM1, CM3D, and CM17) by a two-dimensional electrophoretic method that does not dissociate the inhibitors in the first dimension. Multiple tetrameric species, resulting from different combinations of the subunits contributed by the two ancestral species, are observed by the same procedure in T. aestivum. The three types of subunits were required for significant activity when the inhibitor of T. turgidum was reconstituted from the purified subunits, whereas, in the case of T. tauschii, binary mixtures involving subunit CM1 also had some activity. Additional combinations of the subunits present in these two species, which occur in the allohexaploid T. aestivum, were also reconstituted, and their inhibitory activities ranged from 144% to 33% the activity of the reconstituted inhibitor from T. tauschii. The activity of these inhibitors toward the alpha-amylase (1,4-alpha-D-glucan glucanohydrolase, EC 3.2.1.1) of the insect Tenebrio molitor is much greater than that against the salivary enzyme. These observations, together with the previously established chromosomal locations of genes encoding CM proteins, fit a model of alloploid heterosis at the molecular level.

Journal Article↗
PubMed1989

[Parasitic infections in renal transplantation patients].

We performed indirect hemagglutination tests for toxoplasmosis and Chagas disease, complement fixation test for toxoplasmosis, stool examination for parasites and Graham test for enteroparasites in 51 patients before and after renal transplant. Post transplant surveys were performed at 3, 6, 9, 12 and 18 months. 18 patients who were positive for toxoplasmosis remained so and 5 new asymptomatic cases were detected in the post transplant period (15%). Two patients who were positive for Chagas disease remained positive and asymptomatic. One patient receiving a kidney from a Chagas positive donor remains negative. Asymptomatic enteric infection was detected in 45% of patients at some time during follow up: amebic infection (25%), giardiasis (14%) and oxyuriasis (24%). Two patients showed asymptomatic cryptosporidiasis.

Chagas Disease↗
PubMed1987

Epidemiology of Chagas' disease in northern Chile: isozyme profiles of Trypanosoma cruzi from domestic and sylvatic transmission cycles and their association with cardiopathy.

Trypanosoma cruzi was isolated from 98 patients, 59 Triatoma infestans, 51 Triatoma spinolai, and 1 Octodon degus from northern Chile. With few exceptions, stocks originating from domestic hosts were classified, based on their isozyme profile, as principal zymodeme (Z)2, while sylvatic stocks from T. spinolai and the rodent O. degus showed Z1 profiles. These results indicate the existence of separate domestic and sylvatic transmission cycles. Clinical data and T. cruzi isozyme profiles from 107 chronic Chagas' disease patients showed no association between infecting T. cruzi zymodeme and the prevalence of chagasic cardiopathy. However, the age distributions of two groups of patients carrying different zymodemes were significantly different.

Adolescent↗
PubMed1987

[Effect of the addition of a fiber-rich concentrate to a hay-based diet, offered at 2 dietary levels to adult rabbits. 1. Mean retention time of digesta].

The influence of adding a fibre rich concentrate feed (wheat bran or beet pulp) to a hay-based diet (orchard grass-lucerne mixture; 50/50) upon the rate of passage of digesta of these two fractions (hay and concentrate) was measured in three groups of 8 adult doe rabbits (White New Zealand x California). The three diets composed of either 90% hay, or hay + bran or hay + pulp were offered at two levels of feeding, i.e. ad libitum and 2/3 ad libitum. The retention time of the two main fractions was measured by means of two tracers, i.e. ytterbium-169 bound to hay and cerium-141 to bran or pulp. Animals fed on the 90% hay diet excreted more than 90% of the tracer during the first 24 h. The mean retention time (MRT) of this diet was the shortest (on an average 14.8 h). The addition of pulp or bran increased the MRT of the diet by 2 and 4 h, respectively. Feed restriction led to a 5 to 7 h earlier period of caecotrophy with a subsequent lengthening of the MRT by 2 to 4 h according to groups. The two hay + "concentrate" diets gave almost the same 169Yb and 141Ce excretion curves. Thus, the mean retention time seems to be the same for digesta from hay and "concentrate" (non significant deviations).

Animal Feed↗
PubMed1986

Influence of position during examination, and sex of examiner on patient anxiety during pelvic examination.

It has been reported that adult women prefer the semi-sitting position over the supine position for the pelvic examination. We determined the effect of the pelvic examination position and the examiner's gender on adolescent anxiety with the pelvic examination. Adolescent girls (n = 112) aged 12 to 19 years were randomly assigned to a semi-sitting or supine position and to a male or female physician. Before and after the examination questionnaires containing the Spielberger State-Trait Anxiety Inventory and other scales were administered. There were no differences between the groups in pre-examination anxiety or concern. Patients in the semi-sitting group reported fewer negative responses during the examination when examined by a male physician (P less than or equal to 0.009); those in the supine group reported fewer negative responses when examined by a female physician. These findings persisted after controlling for previous pelvic examinations, frequency of sexual activity, and Tanner stage. Patients who had previously had a pelvic examination and were examined in the semi-sitting position by a male physician reported the lowest levels of post-examination anxiety (P less than or equal to 0.02). Patients who had never had a pelvic examination expressed less anxiety if they were examined in the semi-sitting position by a female physician. These data suggest that the patient's previous history of pelvic examinations and the gender of the examiner should be considered when selecting the pelvic examination position.

Adolescent↗
PubMed1986

Effect of triflusal and other salicylic acid derivatives on cyclic AMP levels in rat platelets.

The effect of triflusal, acetylsalicylic acid (ASA), and of their principal metabolites 2-hydroxy-4-trifluoromethylbenzoic acid (HTB) and salicylic acid (SA), alone or combined with dypiridamole (DIP) and/or PGE1 on cyclic AMP levels in washed rat platelets (37 degrees C, 4 min), has been determined. DIP at 0.1 mM increased cyclic AMP levels by 25%. The effect of triflusal and HTB was significant at therapeutic concentrations of triflusal (1 mM: 36% increase) and HTB (0.5 mM: 37% increase). The effect of HTB was always greater than that of triflusal. ASA, at 1 mM and 5 mM, alone or combined with PGE1 was without effect. When 1 mM triflusal was combined with 0.1 mM DIP an increased effect was obtained (95%). ASA, at the highest concentration tested (5 mM), did not modify the DIP-induced increase of cyclic AMP levels.

Alprostadil↗
PubMed1984

Malignant mixed Müllerian tumors of the uterus.

One hundred and eight patients with a diagnosis of malignant mixed müllerian tumors of the uterus treated at the M.D. Anderson Hospital from 1948 through 1977 were analyzed. Pathology was reviewed and subdivided according to the sarcomatous element. No difference in pattern of recurrence or survival could be demonstrated between homologous, heterologous, or undifferentiated sarcomatous elements. Nine patients were treated with only palliative intent due to advanced local disease combined with poor medical condition. Of the remaining 99 patients, 87% had minimum surgical procedures of total abdominal hysterectomy. All but two of these patients had adjunctive radiation either preoperatively or postoperatively. The 5-year survival rate was 38%. There was frequent upstaging at surgery in all stages except IA. Patients with tumor confined to the uterus at the time of surgery had a 5-year disease-free survival of 52%. When there was extension outside of the uterus, the 5-year disease-free survival dropped to 28%. The locoregional recurrence rate was 17%.

Combined Modality Therapy↗
PubMed1984

The prognostic significance of endodermal sinus tumor histology among patients treated for stage III nonseminomatous germ cell tumors of the testes.

A retrospective study was undertaken to determine the prognostic significance of endodermal sinus tumor (EST) elements in 56 patients with Stage III nonseminatous germ cell tumors of the testes (NSGCTT). The study patients were treated with conventional vinblastine, bleomycin and cisplatinum chemotherapy prior to our recognition of EST as a distinct entity. Twenty-one (37.5%) of the patients had EST elements in their tumors. Nineteen patients had EST in their primary testis tumor, whereas two had EST in metastatic sites only. Prognostic criteria (tumor volume, Dixon-Moore classification and chemotherapy vinblastin and bleomycin [VB] and VB plus cisplatin [VB + P] ) were similar in EST and non-EST patients. Long-term disease-free survival was significantly poorer for patients with Stage III NSGCTT containing EST (38%) compared with those not containing EST (71%) (P = 0.04). All 12 patients with small volume disease (III-B1-III-B2), independent of the presence of EST, are alive and free of disease for more than 2 years. Only 6 of 18 patients (33%) with advanced disease and EST are alive and free of disease, whereas 17 of 26 (65%) of patients with advanced disease not containing EST are alive and free of disease (P = 0.074). The addition of single agent bolus cisplatin to the treatment of patients with advanced disease achieved no improvement in survival. Endodermal sinus tumor must be included in future studies of advanced Stage III NSGCTT as an important prognostic variable.

Abdominal Neoplasms↗