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Biomedical subjects

M M Costa

Publications and source records attributed to M M Costa.

At least 19 recordsLinked to original sources
PubMed2006

Turbot TNFalpha gene: molecular characterization and biological activity of the recombinant protein.

The tumor necrosis factor (TNF) superfamily is composed by several proteins with similar structure and functions. One of the main representatives of this family is TNF-alpha (TNFalpha), a proinflammatory cytokine which is produced by different immune cells and presents a wide variety of activities. Using the RACE technique, we have cloned and sequenced the turbot TNF cDNA. The analysis of its sequence showed several conserved motifs characteristic of members of the TNFalpha family. A phylogenetic tree constructed with different TNFs of fish and mammals grouped our sequence within the fish TNFalpha cluster. Therefore, the turbot TNF here studied was identified as TNFalpha. The complete TNFalpha gene was obtained by gene walking, and, similarly to the other known fish TNFalpha genes, presented three introns and four exons. A PCR was designed to study the turbot TNFalpha expression in vivo using as stimulus the bacteria Vibrio pelagius strain Hq222 and virus VHSV. The expression of the cytokine happened early after injection, and it was dependent on the pathogen injected and organ analyzed. Virus induced a higher TNFalpha expression, but this response was shorter in time than that induced by bacteria. In addition, TNFalpha expression was in general higher in kidney than in liver, as expected since the former is the haematopoietic organ of fish. The turbot recombinant TNFalpha (rTNFalpha) was obtained by IPTG induction of bacteria transformed with the pET15b-TNFalpha construct, and it was purified in native conditions. The recombinant protein was approximately 20 kDa in size, and its biological activity was assessed in vitro. No effect of the rTNFalpha neither alone nor in combination with LPS was observed on the chemiluminescence activity of turbot macrophages at any time tested. However, NO production was enhanced by the recombinant protein alone or with LPS 72 h after the addition of the treatments. Finally, turbot rTNFalpha was able to recruit and activate inflammatory cells when injected in gilthead seabream, although to a lesser extent than gilthead seabream rTNFalpha.

Amino Acid Sequence↗
PubMed2003

Phenotypic and molecular characterization of bovine Campylobacter fetus strains isolated in Brazil.

The objective of the present study was to characterize the phenotypic and molecular aspects of Campylobacter fetus strains isolated from bovine herds with reproductive problems. Thirty-one Brazilian field isolates, together with one reference strain of each subspecies of C. fetus, were analyzed. The strains were submitted to phenotypic identification followed by subspecies characterization using the polymerase chain reaction (PCR) and numeric evaluation of restriction fragment length polymorphism (RFLP) separated by pulsed-field gel electrophoresis (PFGE). Phenotypically, 4 isolates (12.1%) were classified as C. fetus subsp. fetus, and 29 isolates (87.9%) were classified as C. fetus subsp. venerealis. However, according to molecular analysis, only 1 isolate (3.0%) was classified as C. fetus subsp. fetus (the reference strain), whereas 32 isolates (97.0%) were considered C. fetus subsp. venerealis. SalI digestion of C. fetus genomic DNA, obtained from the 33 strains, yielded 7-10 DNA fragments ranging in size from 40 to 373kb, with 12 distinct patterns. Furthermore, the numeric analysis by neighbor-joining of the DNA from the 33 strains resulted in a dendrogram in which 2 distinct groups were identified. It was concluded that phenotypic characterization of C. fetus subspecies might lead to erroneous classification of field isolates. Although RFLP-PFGE is a powerful and reliable technique to characterize C. fetus, it has the inconvenience of being time consuming and laborious. Whereas PCR, besides providing rapid results, was found to be reliable and convenient for the characterization of field isolates of C. fetus.

Animals↗
PubMed2003

DHEA treatment of Alzheimer's disease: a randomized, double-blind, placebo-controlled study.

OBJECTIVE: To compare the efficacy and tolerability of dehydroepiandrosterone (DHEA) vs placebo in AD. METHOD: Fifty-eight subjects with AD were randomized to 6 month's treatment with DHEA (50 mg per os twice a day; n = 28) or placebo (n = 30) in a multi-site, double-blind pilot trial. Primary efficacy measures assessed cognitive functioning (the AD Assessment Scale-Cognitive [ADAS-Cog]) and observer-based ratings of overall changes in severity (the Clinician's Interview-Based Impression of Change with Caregiver Input [CIBIC-Plus]). At baseline, 3 months, and 6 months, the ADAS-Cog was administered, and at 3 and 6 months, the CIBIC-Plus was administered. The 6-month time point was the primary endpoint. RESULTS: Nineteen DHEA-treated subjects and 14 placebo-treated subjects completed the trial. DHEA was relatively well-tolerated. DHEA treatment, relative to placebo, was not associated with improvement in ADAS-Cog scores at month 6 (last observation carried forward; p = 0.10); transient improvement was noted at month 3 (p = 0.014; cutoff for Bonferroni significance = 0.0125). No difference between treatments was seen on the CIBIC-Plus at either the 6-month or the 3-month time points. CONCLUSIONS: DHEA did not significantly improve cognitive performance or overall ratings of change in severity in this small-scale pilot study. A transient effect on cognitive performance may have been seen at month 3, but narrowly missed significance.

Aged↗
PubMed2001

Betainium trifluoroacetate.

The title compound, C5H12NO2+*C2F3O2- or BET+*CF3COO- [BET is trimethylglycine (betaine); IUPAC: 1-carboxy-N,N,N-trimethylmethanaminium inner salt], contains pairs of betainium and trifluoroacetate ions forming a dimer bridged by a strong hydrogen bond between the carboxyl and carboxylate groups of the two ions. The molecular symmetry of the cation is close to Cs, with protonation occurring at the carboxy O atom positioned anti to the N atom. The trifluoroacetate anions are disordered over two positions. In one, the conformation of the CF3 group is staggered with respect to the carboxylate group, in the other, it is close to an eclipsed conformation. The sole hydrogen bond present in the structure is the strong O-H...O bond between the anion and the cation.

Acetates↗
PubMed2001

Volumetric quantification of the gastric emptying: computer-based method for generation of volumetric index from fluoroscopic images.

We developed an automated software-based procedure for estimation of the volume variation of the stomach using videofluoroscopic analysis of the gastric emptying. We used radiological images with postero-anterior incidence of eight healthy volunteers and in vitro experimental tests, with different volumes and concentrations of the contrast medium. This computational method generates an index that measures, in the three dimensions, the dynamic behaviour of gastric emptying. Using adequate contrast concentration (barium sulphate solution), it is possible to determine volume behaviour from density variations. This software can automate this computation, facilitating the amount of work, avoiding mistakes and improving reproducibility.

Adult↗
PubMed2001

Functional importance of conserved domains in the flowering-time gene CONSTANS demonstrated by analysis of mutant alleles and transgenic plants.

CONSTANS promotes flowering of Arabidopsis in response to long-day conditions. We show that CONSTANS is a member of an Arabidopsis gene family that comprises 16 other members. The CO-Like proteins encoded by these genes contain two segments of homology: a zinc finger containing region near their amino terminus and a CCT (CO, CO-Like, TOC1) domain near their carboxy terminus. Analysis of seven classical co mutant alleles demonstrated that the mutations all occur within either the zinc finger region or the CCT domain, confirming that the two regions of homology are important for CO function. The zinc fingers are most similar to those of B-boxes, which act as protein-protein interaction domains in several transcription factors described in animals. Segments of CO protein containing the CCT domain localize GFP to the nucleus, but one mutation that affects the CCT domain delays flowering without affecting the nuclear localization function, suggesting that this domain has additional functions. All eight co alleles, including one recovered by pollen irradiation in which DNA encoding both B-boxes is deleted, are shown to be semidominant. This dominance appears to be largely due to a reduction in CO dosage in the heterozygous plants. However, some alleles may also actively delay flowering, because overexpression from the CaMV 35S promoter of the co-3 allele, that has a mutation in the second B-box, delayed flowering of wild-type plants. The significance of these observations for the role of CO in the control of flowering time is discussed.

Alleles↗
PubMed2001

Conformation of cationic N,N-dimethylglycine in dimethylglycinium trifluoroacetate.

In the title compound, C(4)H(10)NO(2)(+).C(2)F(3)O(2)(-), the main N-C-COOH skeleton of the protonated amino acid is nearly planar. The C=O/C-N and C=O/O-H bonds are syn and the two methyl groups are gauche to the methylene H atoms. The conformation of the cation in the crystal is compared to that given by ab initio calculations (Hartree-Fock, self-consistent field molecular-orbital theory). The trifluoroacetate anion has the typical staggered conformation with usual bond distances and angles. The cation and anion form dimers through a strong O-H.O hydrogen bond which are further interconnected in infinite zigzag chains running parallel to the a axis by N-H.O bonds. Weaker C-H.O interactions involving the methyl groups and the carboxy O atoms of the cation occur between the chains.

Crystallography, X-Ray↗
PubMed2000

Sarcosinium trifluoroacetate.

The title compound, C(3)H(8)NO(2)(+).C(2)F(3)O(2)(-), crystallizes in space group C2/c. The main N-C-COOH skeleton of the protonated sarcosine molecule is almost perfectly planar. The trifluoroacetate anion has a staggered conformation and typical bond distances and angles. The CF(3) group is probably slightly disordered. The structure is stabilized by an extensive network of strong O-H.O hydrogen bonds and weaker N-H.O bonds.

Crystallography, X-Ray↗
PubMed1999

Estrogen replacement therapy and cognitive decline in memory-impaired post-menopausal women.

BACKGROUND: Estrogen replacement therapy (ERT) may delay dementia-related cognitive decline in post-menopausal women, but few studies have longitudinally examined this relationship and none has controlled for baseline functioning or concurrent medication. METHODS: We report the results of a 1-year retrospective longitudinal study examining cognitive functioning in female estrogen and nonestrogen users (n = 3128) who presented to the state of California memory disorder clinics in a naturalistic multisite study of senile dementia, Alzheimer's type (SDAT), and other cognitive impairments. RESULTS: At baseline, estrogen users had significantly lower rates of SDAT diagnoses (possible and probable) than nonestrogen users, and significantly higher rates of the lesser diagnoses of "cognitive impairment" and "no dementia." ERT was significantly associated with higher cognitive functioning at baseline and at 1 year follow-up (n = 358). Nonestrogen users deteriorated significantly from baseline to follow-up; estrogen users did not. Results were similar in groups matched on baseline Blessed-Roth Dementia Rating Scale (BRDRS) ratings (n = 32) and in a variety of subpopulations. CONCLUSIONS: These findings are consistent with estrogen acting as a protective factor against cognitive deterioration in post-menopausal women with SDAT and other cognitive impairments, and may suggest an increased effect in earlier stages of cognitive impairment.

Aged↗
PubMed1999

Reason, myths and fantasies: preliminary data and reflections about the Portuguese experience with LNG-IUS-induced hypomenorrhea.

OBJECTIVE: To evaluate the efficacy and tolerance of the levonorgestrel-releasing intrauterine system (LNG-IUS) among Portuguese women, with particular emphasis on the implications of changes in bleeding pattern. STUDY DESIGN: Forty healthy premenopausal women (average age 42.7 +/- 4.5 years) were recruited in each one of the three Portuguese centers (a total of 120) where the LNG-IUS was used as a contraceptive method during a maximum period of 5 years. All women had previously given their informed consent and were informed about the eventual changes in bleeding pattern. Serum ferritin levels and hemogram measurements were performed before and 1 year after the introduction of the IUS. The results were analyzed by the Student t test (raw data and paired test). RESULTS: Preliminary data showed a continuation rate of 70% with an excellent efficacy rate (no pregnancies) 1 year after the introduction of the IUS. The hypomenorrhea rate was 35% while 12.5% of the women had amenorrhea. The average increase in serum ferritin level was 13 ng/ml and of hemoglobin 0.4 g/dl. The comparisons of hemoglobin results were statistically significant (p = 0.05, t raw data and p = 0.028, t paired test). Most complaints were related to cultural difficulties in accepting the changes in menstrual bleeding pattern. CONCLUSION: In order to minimize and control the most common menstrual bleeding side-effects that occur when using this IUS, as well as to improve the continuation rate, clinicians must make a judicious choice of potential users, owing to the psychological and cultural implications that menstrual bleeding changes can have, mainly among women of low socioeconomic levels. Moreover, non-contraceptive therapeutic benefits should be emphasized.

Adult↗
PubMed1995

[Nonalcoholic steatohepatitis].

The authors present a case of a nonalcoholic steatohepatitis, with progression to liver cirrhosis in an obese female patient. A review of the literature, possible evolution, and principle pathological processes involved is made. Attention is drawn to obesity as a risk factor in the progression of steatohepatitis and the advantage of performing liver biopsies in selected cases as a fundamental technique of diagnosis.

Biopsy↗
PubMed1992

Splenic lymphoma with villous lymphocytes in two sisters.

Splenic lymphoma with villous lymphocytes is a new entity characterised by the presence of atypical lymphocytes in the peripheral blood and bone marrow, and splenic infiltration in the white and red pulp. Cell membrane markers are those of a B mature cell, and no particular chromosomal abnormalities have been associated with this disease. A case of this rare lymphoma occurred in two sisters. Histological examination of splenic tissue was identical in both cases, with the same immunological surface markers, although the clinical and laboratory features were different. Karyotype analysis showed an abnormal pattern in one case; no environmental causative factor could be detected. Familial cases of other lymphoproliferative disorders have been reported, but no consistent common link has been found. It is suggested that further reports of this lymphoma, including cytogenetic and molecular studies, may provide a better understanding of the aetiology.

Aged↗