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Biomedical subjects

A Nieto

Publications and source records attributed to A Nieto.

At least 127 records · Page 7Linked to original sources
PubMed1997

Comparison of morphotypic and genotypic methods for strain delineation in Candida.

We compared two phenotypic methods, colony morphotyping on Sabouraudtripheniltetrazolium agar (STTZ) and serotyping, with two genotypic methods, karyotyping and Random Amplified Polymorphic DNA bands obtained by PCR amplification (RAPD-PCR), for strain delineation in 33 Candida clinical isolates and two C. albicans strains from culture collections. Analysis of isolates on STTZ showed 11 different morphotypes. In two patients there was a switch in the morphotype coincidential with a change in the susceptibility of the isolates to azole antifungals. C. albicans isolates were divided into two serotypes. Sixteen and 18 different patterns were identified among the Candida isolates by karyotyping and RAPD-PCR, respectively. No relationship was found between any of the typing methods used and the source of the isolates. The combination of karyotyping and morphotyping on STTZ yielded useful epidemiological information, since it allowed the differentiation among the Candida species studied and the discrimination of clusters within C. albicans as well as to check the capacity of a strain to generate variants with different susceptibility to some antifungals.

Candida↗
PubMed1997

Cloning and characterization of CSP37, a novel gene encoding a putative membrane protein of Candida albicans.

In the course of an analysis of the functions and assembly of the cell wall of Candida albicans, we have cloned and characterized a gene, which we designated CSP37 (cell surface protein), encoding a 37-kDa polypeptide which is a membrane-associated protein. The gene was isolated by immunological screening of a DNA library constructed from mycelial cells with a polyclonal serum raised against cell walls of this morphology. Analysis of the nucleotide sequence of a corresponding genomic DNA fragment revealed a single open reading frame which encodes a predicted protein of 321 amino acids with no significant homology to others in the databases. Disruption of the CSP37 gene by the method described by Fonzi and Irwin (Genetics 134:717-728, 1993) eliminated expression of the Csp37 protein. The mutant strains showed no apparent defect in cell viability, growth, or cell wall assembly but displayed attenuated virulence in systemic infections induced in mice and reduced the ability to adhere to polystyrene.

Amino Acid Sequence↗
PubMed1997

Evaluation of gestrinone after surgery in treatment of endometriosis.

OBJECTIVE: The clinical and histological efficacy of gestrinone in the treatment of endometriosis was evaluated. METHODS: A prospective study was performed with longitudinal follow-up of 4 years duration (minimum) for each patient. Twenty-five cases of endometriosis were treated with gestrinone (as a drug of choice or associated with other local surgical treatment) during 6 months. RESULTS: The total or partial response to pain was induced with treatment in 19 of the 20 cases (95%), and posttreatment pregnancies were induced in 3 of the 9 cases of infertility (33.3%). The global clinical efficacy was as follows: none (n = 5, 20%), poor (n = 2, 8%), moderate (n = 2, 8%), good (n = 3, 12%) and excellent (n = 13, 52%). The pretreatment American Fertility Society score was 23.1 +/- 3.8 points (2-58) and that after treatment (re-examination) 7.8 +/- 3.7 points (0-52), p < 0.01. Global histological efficacy (n = 17) results were as follows: none (23.6%), poor (0%), moderate (5.8%), good (35.3%) and excellent (35.3%). CONCLUSIONS: Gestrinone is presented as a drug with an efficacy comparable to other pharmacological agents currently available in the medical treatment of endometriosis. Adequate posology and acceptable effectiveness were also observed.

Abdominal Pain↗
PubMed1997

[Sequential chemotherapy and radiotherapy in the treatment of locally advanced carcinoma of the head and neck].

In patients with non-resectable carcinoma of the head and neck, radiotherapy produces an average survival of 12 months. Neoadjuvant chemotherapy followed by radiotherapy has been shown to prolong survival and preserve organ structure and function, and to reduce systemic relapses in patients with advanced, resectable disease. An analysis was made of 35 patients treated with sequential chemotherapy and radiotherapy, 20 with non-resectable disease and 15 with resectable disease who refused surgery. Treatment consisted of 4 cycles of cisplatin + 5-fluoruracil in a 96-h continuous intravenous infusion in 16 patients, and the same treatment with leucovorin in 19 patients. After chemotherapy, the patients underwent cobalt irradiation of the primary tumor and neck. Chemotherapy produced a complete response rate of 46% and a partial response rate of 28%, yielding an overall rate of 74%. After radiotherapy, the CR increased to 63%. After 92 months of maximum follow-up, overall survival was 20% and median survival was 25 months. Locoregional relapses were the main cause of treatment failure. Our results suggest that sequential chemo-radiotherapy achieved encouraging CR rates with no significant increase in toxicity, prolonged survival in non-resectable patients, and enabled organ preservation in patients with resectable disease.

Adult↗
PubMed1997

Different postnatal growth between disproportionate and proportionate fetal growth retardation at term.

OBJECTIVE: To evaluate the postnatal growth of full-term infants with fetal growth retardation (FGR) syndrome and their subgroups (disproportionate and proportionate) after six months of delivery. METHODS: This is a prospective follow-up study of 200 full-term gestations. We compare 100 FGRs (34 cases of FGR-disproportionate and 66 FGR-proportionate) infants against 100 normal infants/controls. At the sixth months of postnatal life, the infants were subjected to a standard paediatric evaluation and examination. RESULTS: At the sixth months of postnatal life, the infant weight was 7.183 g +/- 727 in the FGR group vs. 8.019 g +/- 823 in the control group, p < 0.001. 31% of FGR infants were found under the 10th percentile value as read for the 6th months standard, whereas the same value was detected in only 3% of control infants, p < 0.001. Likewise, 38% of FGR cases were under the 10th percentile of height versus 7% of control cases, p < 0.001. Proportionate FGR infants showed a higher increase of height in comparison to those from a disproportionate group (17.3 cm +/- 1.4 vs. 15.5 cm +/- 3.4, p < 0.05). A negative correlation was found between neonatal ponderal index (NPI) and weight gain (R = -0.16, p < 0.05). CONCLUSIONS: Six months after delivery, weight and height were lower in FGR infants than in controls. At that age, disproportionate and proportionate FGR infants had similar weight and height, being the height catch-up more significant in proportionate ones.

Body Height↗
PubMed1996

Interactions of progesterone-dependent endometrial nuclear factors with the promoter of the rabbit uteroglobin gene.

We have studied the in vitro interactions of a promoter fragment of the rabbit uteroglobin (UG) gene with endometrial nuclear factors from either control rabbits or progesterone-treated animals, a treatment that induces the transcription of the gene in the endometrium. Nuclear factors from liver, which does not express UG, were also compared. Using DNase I footprinting, several protected zones were observed on the promoter; some of these were common to all three nuclear extracts, whereas others seemed to be specific to progesterone treated endometrium. One of these footprints was over the TATA box region. A 28-bp synthetic oligonucleotide encompassing the sequence of that region was used as a probe in electrophoretic mobility shift assays (EMSA) and UV-crosslinking assays. In EMSA experiments, endometrial nuclear extracts, but not liver extracts, generated a major retarded complex that was strongly increased following progesterone stimulation. Competition experiments with unlabeled mutated versions of the probe showed that sequences 3' downstream from the TATA box (but not this motif) were responsible for the formation of the complex. UV-crosslinking experiments indicated that the probe interacted with two progesterone-dependent nuclear proteins of 55 and 60 kDa, different from the TATA box-binding protein. The results suggest that progesterone induction of the UG gene in the endometrium might be mediated by both general and tissue-specific nuclear factors.

Animals↗
PubMed1996

The C-terminal DNA-binding domain of Chironomus BR gene products shows preferential affinity for (dA.dT)-rich sequences.

Balbiani ring genes (BRs), the most active loci in the polytene chromosomes of the salivary gland of the midge Chironomus (Diptera), code for secretory giant peptides (the sp-I family). Evidence previously reported indicated that the conserved C-terminal region of proteins of the sp-I family had DNA-binding properties (assayed with sp-Ia), and one such region, derived from BR2.2, which codes for the product sp-Ib, might occur as a stable independent peptide, being transferred to the nucleus where it is detectable in the large BRs (BR1 and BR2), among other structures, by immunostaining. Here, we show that the C-terminal portion of one of the BR gene products, expressed as a glutathione-S-transferase fusion protein shows preferential affinity for A.T-rich sequences and binds with varying affinity to restriction fragments of the A.T-rich BR1 promoter. The binding was inhibited by distamycin, suggesting that the interaction involves the minor groove of the DNA. Analysis of the promoter fragments by gel electrophoresis indicated that most appeared to present a conspicuous bend, as deduced from their anomalous electrophoretic mobilities. Furthermore, the affinity of the C-terminal domain for the different promoter fragments appeared to correlate with the degree of bending. Thus, the C-terminal domain might play a role in controlling gene expression by binding to A.T-rich sequences, including those of the BR genes.

Animals↗
PubMed1996

Regional differences in uteroglobin biosynthesis along the rabbit oviduct: immunohistochemical and biochemical studies.

The biosynthesis of uteroglobin in three regions of the rabbit oviduct was assessed by means of immunocytochemical studies, radioimmunoassay measurements of the protein, and quantitative determinations of its mRNA. Immunocytochemical observations suggested that the number of immunopositive cells and the intensity of their immunolabelling were similar in the distal (infundibular) and the middle regions. In contrast, the isthmic portion appeared to contain less positive cells and weaker immunolabelling. In agreement with these findings, biochemical studies demonstrated that the tissue contents of uteroglobin and its mRNA were similar in the distal and the middle regions whereas the concentrations of both were about three-to four-fold lower in the isthmic portion. The results are discussed in relation to a possible role for uteroglobin in maintaining appropriate environmental conditions for the gametes and the early embryo.

Animals↗
PubMed1996

Immunocytochemical detection of growth factors (PDGF and TGF beta) in equine chronic pneumonia.

The roles played by platelet-derived growth factor (PDGF) and transforming growth factor beta (TGF beta) in the development of pulmonary fibrosis in equine chronic pneumonia varied greatly. Macrophages, epithelial cells and fibroblasts were identified as a source of PDGF, the principal role of which was related to its mitotic effect on epithelial cells, and particularly on fibroblasts in the final phase of the disease. TGF beta was detected in epithelial cells in all three phases of the disease and in fibroblasts in the last phase. However, the role of TGF beta in this pulmonary disease is not clear because its expression in the cytoplasm of fibroblasts in areas of strong collagenation during the last phase was weak. Nonetheless, it was responsible for the production and release of collagen during the stage of total fibrosis.

Animals↗
PubMed1996

Allergy to latex in spina bifida: a multivariate study of associated factors in 100 consecutive patients.

BACKGROUND: Latex allergy is quite frequent in patients who have undergone multiple operations, such as children with spina bifida. OBJECTIVE: This investigation was carried to study the prevalence and risk factors associated with latex allergy in patients with spina bifida. METHODS: We studied 100 consecutive patients by skin prick tests and quantified specific IgE to latex with commercial antigens. RESULTS: Twenty-nine patients were sensitized to latex, although 14 (49%) did not report symptoms. There was a statistical association (p < 0.05) between sensitization and age, number of operations, number of cystourethrograms, antecedents of intermittent bladder catheterization, personal antecedents of atopy, the presence of a ventricular-peritoneal shunt, and levels of serum total IgE, the latter both in absolute units per milliliter and relative z-units. Through a forward stepwise multiple logistic regression analysis, the number of operations, serum total IgE in z-units, the presence of a ventricular-peritoneal shunt, and personal antecedents of atopy were selected as the synergistic variables that most contributed to identification of sensitized patients. The mathematical model so developed had an area under the receiver operating characteristic curve of 0.95. Alternative models always retained two variables, the number of operations and levels of IgE. CONCLUSION: Allergy to latex is mainly related to the number of operations and to the atopic diathesis of patients.

Adolescent↗
PubMed1996

Antibody response of Echinococcus granulosus infected mice: recognition of glucidic and peptidic epitopes and lack of avidity maturation.

The antibody response was followed weekly during 68 weeks in 17 Balb/c mice intraperitoneally (i.p.) infected with 2000 Echinococcus granulosus protoscoleces (PSC) and in three mice i.p. immunized with 2000 dead PSC. Antibodies against hydatid cyst fluid (HCFA) and its peptidic (periodate-resistant) and carbohydrate (periodate-sensitive) epitopes were titrated by ELISA. Avidity and the antigen recognition pattern of antibodies were also analysed during infection and immunization by ELISA and immunoblot, respectively. The antibody response of infected mice showed quantitative and qualitative variations during infection, since both titre as well as recognition of peptide and carbohydrate epitopes in HCFA depended on time post infection. No avidity maturation was evident during the course of infection. Sera from infected mice recognized the 38 kDa subunit of Ag5 but did not react with the 8 kDa subunit of AgB. On the contrary, the antibodies response of immunized mice showed only one peak of antibodies that recognized both peptidic and carbohydrate epitopes of HCFA. In addition, sera from these mice recognized mainly 60 and 110 kDa bands. Our results suggest that: a) avidity and antigen recognition patterns of antibodies in mice treated with live PSC are different from those treated with dead PSC; b) antibodies against HCFA glucidic or peptidic epitopes appear at different times post infection.

Animals↗
PubMed1996

Carbohydrates on the surface of Echinococcus granulosus protoscoleces are immunodominant in mice.

A carbohydrate enriched soluble fraction (CHP) was prepared by mild treatment of viable Echinococcus granulosus protoscoleces (PSC) with the enzyme endoglycosidase-F (endo-F) and characterized by SDS-PAGE, glycoside- inhibition ELISA, and immunoblotting. Three groups of four BALB/c mice were immunized with the CHP, with the remaining deglycosylated PSC (DGP) and with dead PSC (DPSC) to analyse the relative immunogenicity of carbohydrates on the surface of PSC. A fourth sentinel group was not immunized. The antibody response was analyzed during primary and hyperimmune responses. Specific antibody titres (IgG and IgM) against somatic PSC antigens (PSA) were evaluated by ELISA and their antigen recognition pattern by immunoblotting, discriminating carbohydrate and peptide specific antibody responses by periodate treatment of PSA. The avidity index of those antibodies and the titer of non-specific immunoglobulins during the whole protocol were evaluated by ELISA in vitro mitogenic activity of CHP was also evaluated. The results indicated: 1) immunodominance of surface carbohydrate epitopes from PSC, 2) predominant IgM and low avidity response against these epitopes, 3) a dramatic increase of non-specific antibody titres and 4) in vitro mitogenic activity of CHP.

Animals↗
PubMed1996

Two different 8 kDa monomers are involved in the oligomeric organization of the native Echinococcus granulosus antigen B.

The present work describes the purification and characterization of antigen B (AgB), the thermostable lipoprotein from E. granulosus. Native AgB was purified to homogeneity by a new strategy involving adsorption on DEAE-Sepharose, followed by immunopurification. The purified antigen was analysed using mapped monoclonal antibodies (MoAbs) and peptide isolation by in situ digestion in gels after SDS-PAGE. Epitope mapping of 7 MoAbs using PEPSCAN, synthetic peptides and competition studies, revealed that six of them defined epitopes which clustered the N-terminal extension of a 8 kDa subunit of AgB, whilst the remaining one reacted against the stretch RGLIAEGE, corresponding to the C-terminus. The epitopes defined by the seven MoAbs were found to be present in all the subunits. Furthermore, the similarities of the peptide finger prints obtained by HPLC analysis and amino acid sequencing of tryptic peptides isolated from the 8, 16 and 24 kDa subunits, indicated that they have most if not all the amino acid sequence in common. We also found evidence that the band representing a component of an apparent molecular weight of 8 kDa in SDS-PAGE, believed to be the smallest subunit of AgB, contained at least two components, which may constitute the building blocks of the higher molecular weight subunits.

Amino Acid Sequence↗
PubMed1996

Mutational analysis of the influenza virus A/Victoria/3/75 PA protein: studies of interaction with PB1 protein and identification of a dominant negative mutant.

The RNA polymerase activity and PB1 binding of influenza virus PA mutants were studied using an in vivo-reconstituted polymerase assay and a two hybrid system. Deletions covering the whole PA protein abolished polymerase activity, but the deletion of the 154 N-terminal amino acids allowed PB1 binding, indicating that the PA protein N terminus is not absolutely required for this interaction. Further internal or C-terminal deletions abolished PB1 interaction, suggesting that most of the protein is involved in this association. As a novel finding we showed that a single amino acid insertion mutant, PAI672, was responsible for a temperature-sensitive phenotype. Mutant PAS509, which had a serine insertion at position 509, bound to PB1 like wild-type PA but did not show any polymerase activity. Over-expression of PAS509 interfered with the polymerase activity of wild-type PA, identifying PAS509 as a dominant negative mutant.

Animals↗