Biomedical subjects

C Gomes

Publications and source records attributed to C Gomes.

At least 19 recordsLinked to original sources

PubMed2006

Chagas disease.

Chagas disease is the clinical condition triggered by infection with the protozoan Trypanosoma cruzi. The infection is transmitted by triatomine insects while blood feeding on a human host. Field studies predict that one third of an estimated 18 million T cruzi-infected humans in Latin America will die of Chagas disease. Acute infections are usually asymptomatic, but the ensuing chronic T cruzi infections have been associated with high ratios of morbidity and mortality: Chagas heart disease leads to unexpected death in 37.5% of patients, 58% develop heart failure and die and megacolon or megaoesophagus has been associated with death in 4.5%. The pathogenesis of Chagas disease appears to be related to a parasite-induced mutation of the vertebrate genome. Currently, treatment is unsatisfactory.

Acute Disease↗

PubMed2004

Phenolic acid derivatives with potential anticancer properties--a structure-activity relationship study. Part 1: methyl, propyl and octyl esters of caffeic and gallic acids.

The antiproliferative and cytotoxic properties of polyphenolic acid derivatives, structurally related with the natural models caffeic and gallic acids, have been tested in human cervix adenocarcinoma cells (HeLa). Simultaneous structural information was obtained for these compounds through theoretical ab initio methods. This study was conducted for the following esters: methyl caffeate (MC, 1), propyl caffeate (PC, 2), octyl caffeate (OC, 3), methyl gallate (MG, 4), propyl gallate (PG, 5) and octyl gallate (OG, 6). A significant growth-inhibition effect was assessed for some of these compounds, clearly dependent on their structural characteristics. Marked structure-activity relationships (SARs)--namely the number of hydroxyl ring substituents--were found to rule the biological effect of such systems.

Antineoplastic Agents↗

PubMed2002

Sclerosis of gross cysts of the breast: a three-year study.

Breast cysts can be separated into two types: Type I cyst with a lining epithelium which shows apocrine metaplasia, and Type II cyst with an epithelium which is markedly attenuated or absent. The risk of subsequent breast cancer among patients with Type I cysts can be up to 4. The standard treatment is fine needle aspiration, but 20% of the cysts recur. Pharmacological treatment has been tried, which reduces size and volume, but has side-effects and a high recurrence rate post-treatment occurs. The objectives of this prospective study were to sclerose the cyst, induce its regression and prevent or reduce recurrence rate, with the administration of a sclerosing solution (Sclerovein) within the cyst post-aspiration. Fifty-seven patients were followed in the study, 37 with Type I cysts and 20 with Type II cysts. At the end of six months all patients with Type II cysts had no detectable cyst. On the other hand, two patients still had a residual Type I cyst. At the end of three years our recurrence rate appears to be less than 2%, with one patient with a possible recurrence. No significant side-effects were observed. The use of Sclerovein is a simple and safe alternative in the treatment of recurring cysts.

Adolescent↗

PubMed2001

Population genetics of four PKLR intragenic polymorphisms in Portugal and São Tomé e Príncipe (Gulf of Guinea).

Four intragenic PKLR polymorphisms [1705A/C, 1738C/T. T10/19, and (ATT)n microsatellite] were studied in normal population samples of Central Portugal and São Tomé e Príncipe, a small archipelago located in the Gulf of Guinea, West Africa. For all loci, the observed genotype distributions do not deviate from Hardy-Weinberg equilibrium. The allele frequencies found in the Portuguese population are similar to those previously described in Caucasian populations. Mother-child pair analysis for the (ATT)n microsatellite does not show deviations to the Mendelian rules. In São Tomé e Príncipe the biallelic polymorphisms 1705A/C, 1738C/T, and T10/19 presented inverse allelic frequencies when compared with the Portuguese population. Two new alleles were found at the (ATT)n microsatellite. Significant statistical differences were found between both populations. The results showed that São Tomeans had higher haplotype diversity and lower linkage disequilibrium among the polymorphic sites. The PKLR intragenic polymorphisms, commonly used in haplotype analysis with the gene mutations in PK-deficient patients, can thus be successfully employed in anthropological genetics.

Atlantic Islands↗

PubMed2000

On the mechanism of resistance to channel-forming colicins (PacB) and tellurite, encoded by plasmid Mip233 (IncHI3).

Plasmids of the H incompatibility complex confer protection against all known channel-forming colicins (PacB character) and resistance to potassium tellurite (Te(r)) to Escherichia coli strains. A DNA clone (2.2 kbp) from plasmid Mip233 (IncHI3) expressing PacB-Te(r) phenotypes was studied. DNA sequence analysis revealed a high degree of homology with the enzyme O-acetylserine sulfhydrylase. Size of the PacB-Te(r) transcript was estimated as 1200 bases. A single polypeptide was found on SDS-polyacrylamide gel with a molecular mass estimated of 34 kDa. The effect of channel-forming colicins and tellurite was analyzed at physiological and transcriptional levels. Results suggest that the pacB gene product could be a reductase-like enzyme. It is also suggested that presence of the PacB character among H plasmid confers selective advantage on cells sharing an ecological niche.

Amino Acid Sequence↗

PubMed2000

Charged-particle multiplicity near midrapidity in central Au+Au collisions at sqrt[SNN]=56 and 130 GeV.

We present the first measurement of pseudorapidity densities of primary charged particles near midrapidity in Au+Au collisions at sqrt[s(NN)] = 56 and 130 GeV. For the most central collisions, we find the charged-particle pseudorapidity density to be dN/deta|(|eta|<1) = 408+/-12(stat)+/-30(syst) at 56 GeV and 555+/-12(stat)+/-35(syst) at 130 GeV, values that are higher than any previously observed in nuclear collisions. Compared to proton-antiproton collisions, our data show an increase in the pseudorapidity density per participant by more than 40% at the higher energy.

Journal Article↗

PubMed2000

Severe hereditary spherocytosis and distal renal tubular acidosis associated with the total absence of band 3.

Absence of band 3, associated with the mutation Coimbra (V488M) in the homozygous state, caused severe hereditary spherocytosis in a young child. Although prenatal testing was made available to the parents, it was declined. Because the fetus stopped moving near term, an emergency cesarean section was performed and a severely anemic, hydropic female baby was delivered. She was resuscitated and initially kept alive with respiratory assistance and hypertransfusion therapy. Cord blood smears revealed erythroblastosis, poikilocytosis, and red cells with stalk-like elongations. Band 3 and protein 4.2 were absent; spectrin, ankyrin, and glycophorin A were significantly reduced. Renal tubular acidosis was detected by the age of 3 months. Nephrocalcinosis appeared soon thereafter. After 3 years of follow-up the child is doing reasonably well on a regimen that includes regular blood transfusions and daily bicarbonate supplements. The long-term prognosis remains uncertain given the potential for hematologic and renal complications. (Blood. 2000;96:1602-1604)

Acidosis, Renal Tubular↗

PubMed2000

Restriction site mapping of the mitochondrial DNA of the four-wing flyingfish, Hirundichthys affinis.

Mitochondrial DNA was isolated from samples of the four-wing flyingfish, Hirundichthys affinis, collected in Barbados in January 1996 and subjected to restriction enzyme analysis, using 13 restriction endonucleases which recognise hexanucleotide sequences, in single and double digests. The resulting restricted DNA fragments were used to map the 14 enzyme recognition sites of 6 endonucleases (7 had no sites) on the flyingfish mtDNA molecule for the first time. In addition, the mtDNA D-loop region was positioned on the restriction site map, for the first time, by selective restriction digestion of the mtDNA molecule followed by polymerase chain reaction (PCR) amplification of the resulting fragments using specific mtDNA D-loop primers. The size of the flyingfish mtDNA molecule (18 kb) was also determined.

Animals↗

PubMed1999

[Marchiafava-Bignami disease. 3 cases with favorable prognosis].

INTRODUCTION: Marchiafava-Bignami disease is a complication of chronic alcoholism, with acute or subacute demyelination of the corpus callosum. Although subacute and benign forms of the disease have been described since the development of CT scan and MRI, it has usually a poor prognosis. EXEGESIS: We report three cases of Marchiafava-Bignami disease with favorable outcome. One of the patient was comatose upon hospital admission. Interhemispheric dysconnection syndrome was evidenced in two patients. CT scan and MRI showed lesions extending to the callosal white matter in these patients. CONCLUSION: Potential existence of Marchiafava-Bignami disease should be investigated in patients presenting with chronic alcoholism and mental confusion. However, accompanying coma and white matter demyelination should not necessarily be considered of poor prognosis. Clinical evaluation of interhemispheric dysconnection is of value in patients presenting with chronic alcoholism and mental confusion.

Adult↗

PubMed1999

Surgery for endomyocardial fibrosis revisited.

OBJECTIVE: To identify life expectancy after surgery for endomyocardial fibrosis (EMF) and the events that influence it. METHODS: Eighty-three patients with EMF underwent endocardial decortication and atrioventricular valve replacement or repair, between December 1977 and December 1997. There were 66 (79.6%) female and 17 (20.4%) male patients, ranging in age from 4 to 59 years (mean, 31). Thirty-seven (44.5%) had biventricular disease, 34 (41.0%) had disease of the right ventricle alone and 12 (14.5%) had EMF confined to the left ventricle. All were in functional class III or IV (New York Heart Association classification). RESULTS: Sixty-eight (81.9%) patients survived the operation and were followed up for periods ranging from 2 months to 17 years. The total follow-up time was 6290 patient/months (mean, 92 months). There were 15 late deaths, but in six, the cause was not related to the underlying disease. Four (5.8%) patients presented recurrence of the fibrosis and were reoperated on and in six (8.8%), EMF appeared in the other ventricle. Five (7.3%) patients were reoperated on to replace either a valve prosthesis or a native valve which had been preserved during the first procedure. Only 24 (45%) of the 53 surviving patients are in functional class I or II. The actuarial probability of survival at 17 years, including operative mortality, was 55%. CONCLUSION: Surgical treatment of EMF should be considered a palliative procedure because surgery does not alter the progressive nature of the disease. However, surgical therapy is recommended for patients with EMF and heart failure as it is their only hope of survival.

Adolescent↗

PubMed1999

Schimke immuno-osseous dysplasia: case report and review of 25 patients.

Immuno-osseous dysplasia is characterised by spondyloepiphyseal dysplasia, lymphopenia with defective cellular immunity, and progressive renal disease. We describe a patient with a severe form of the disease, review the features of another 24 patients, and discuss the previous classification. The differences between the two groups are not striking, and although similarities are greater between affected sibs, the same diagnosis of Schimke immuno-osseous dysplasia should apply to them all. The aetiology and physiopathology of this rare osteochondrodysplasia of presumed autosomal recessive inheritance remain unknown.

Bone and Bones↗

PubMed1999

First trimester umbilical venous Doppler sonography in chromosomally normal and abnormal fetuses.

In 342 singleton pregnancies in which the patients were undergoing chorionic villus sampling at 11 to 14 weeks of gestation, color Doppler sonography was used to obtain waveforms from the umbilical cord. The prevalence of pulsatile flow in the umbilical vein was higher in the 18 fetuses with trisomy 18 or 13 (16 of 18; 88.9%) than in the 18 fetuses with trisomy 21 (6 of 18; 33.3%) or the 302 chromosomally normal fetuses (73 of 302; 24.2%).

Aneuploidy↗

PubMed1998

The umbilical artery pulsatility index in the first trimester: is there an association with increased nuchal translucency or chromosomal abnormality?

OBJECTIVE: The aim of this study was to examine the possible association between umbilical artery pulsatility index (PI) at 10-14 weeks of gestation and either increased fetal nuchal translucency (NT) or fetal chromosomal abnormality. DESIGN: This was a prospective study of women undergoing chorionic villus sampling (CVS). SUBJECTS: A total of 458 women undergoing CVS were studied; in 418 cases the karyotype was normal and in 19 cases fetal trisomy 21 was identified. METHODS: Data from the women with a normal fetal karyotype and in whom the NT was also normal were used to calculate reference anges for the umbilical artery PI. Associations were sought between umbilical artery PI and increased NT and between the PI and fetal trisomy 21. RESULTS: We found no association between umbilical artery PI and NT, nor was there a difference in the PI between chromosomally normal pregnancies and those with fetal trisomy 21. CONCLUSION: The results suggest that fetoplacental vascular resistance per se does not contribute to increased NT and that measurement of the umbilical artery PI does not contribute to the first-trimester detection of fetal trisomy 21.

Adult↗

PubMed1998

Screening for chromosomal abnormalities at 10-14 weeks: the role of ductus venosus blood flow.

OBJECTIVE: To assess the possible role of Doppler ultrasound assessment of ductus venosus blood flow in screening for chromosomal abnormalities at 10-14 weeks of gestation. METHODS: Ductus venosus flow velocity waveforms were obtained immediately before fetal karyotyping in 486 consecutive singleton pregnancies at 10-14 weeks of gestation. All cases were screened for chromosomal defects by a combination of maternal age and fetal nuchal translucency thickness. The peak systolic and diastolic velocities, the velocity during atrial contraction and the pulsatility index were measured. RESULTS: There were 63 chromosomal defects (38 cases of trisomy 21, 12 cases of trisomy 18, seven cases of trisomy 13, three cases of Turner's syndrome and three cases of triploidy). In 57 (90.5%) cases there was reverse or absent flow during atrial contraction. Abnormal ductus venosus flow was also observed in 13 (3.1%) of the 423 chromosomally normal fetuses. In the chromosomally abnormal group, compared to the normal group, the median heights of the S and D waves were significantly lower and the pulsatility index was significantly higher. However, multivariate regression analysis demonstrated that only the height of the A wave provided a significant independent contribution in distinguishing between the chromosomally normal and abnormal groups. CONCLUSION: These preliminary results suggest that assessment of ductus venous blood flow in pregnancies considered to be at high risk for chromosomal defects may result in a major reduction in the need for invasive testing, with only a small decrease in sensitivity.

Adolescent↗

PubMed1998

Serologic profile of some sexually transmitted diseases in women with squamous intraepithelial lesions.

UNLABELLED: The purpose of this study consisted of the evaluation of some sexually transmitted diseases in patients with cervical pathology, namely squamous intraepithelial lesions. METHODS: a prospective study was performed. Patients with an abnormal cervical smear were submitted to colposcopy, directed biopsy and an immunologic assay for Chlamydia, Herpes Simplex Virus (HSV) types 1 and 2, Cytomegalovirus, Treponema pallidum, Hepatitis B and Human Immunodeficiency Virus I and II. The same parameters were evaluated in women with normal cervical cytology in a matched control group. A comparative study was performed evaluating some epidemiological parameters and the referred immunologic assays. RESULTS: 118 patients were separated into four groups. Statistically significant differences were observed in the personal history of fungi infections, as well as Chlamydia and HSV 2 IgM. CONCLUSION: immunologic assays may prove useful in identifying sexually-transmitted diseases, especially Chlamydia and HSV 2 infections, in Human Papillomavirus infected women.

Adult↗

PubMed1996

Characterization of Legionella species by numerical analysis of whole-cell protein electrophoresis.

The results of a computer-assisted whole-cell protein sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of 291 isolates and 74 reference strains belonging to all known species of the genus Legionella revealed that the majority of the species of this genus can be adequately identified by this method. The type strain of Legionella bozemanii did not cluster with the other strains of this species, and the only strain of Legionella geestiana available clustered with the strains of Legionella feeleii. When we performed a numerical analysis by omitting certain portions of the pattern containing dense bands, all of the species could be distinguished. Our results also show that the type strains of Legionella nautarum and Legionella londiniensis deposited in the National Collection of Type Cultures do not correspond to the type strains deposited in the American Type Culture Collection. We used the results of a fatty acid and ubiquinone composition analysis to complement the SDS-PAGE results for several strains whose identities as determined by indirect immunofluorescence were doubtful. Computer-assisted SDS-PAGE of whole-cell proteins can be used in the classification of Legionella species and to identify and screen large numbers of isolates for further, in-depth taxonomic studies of smaller numbers of strains.

Bacterial Proteins↗

PubMed1996

Computer-aided comparison of protein electrophoretic patterns for grouping and identification of heterotrophic bacteria from mineral water.

The microflora of a natural mineral water was studied immediately after bottling (T0) and after 7 d storage (T7) during 6 months, and isolates were clustered by SDS-PAGE of whole-cell protein profiles. Isolates from each cluster were further characterized by API 20NE, fatty acid composition and quinone profiles. The numerical analysis of the electrophoregrams of all bacteria isolated from the mineral water formed 15 clusters and five unclustered strains. Except for five minor clusters, all clusters were composed of strains isolated over several months. The numerical analysis of the electrophoregrams of bacteria isolated immediately after bottling formed 15 clusters while after 7 d storage only four of these populations could be isolated, indicating the populations present in the mineral water were stable and that changes occurring after bottling probably resulted from a selection process. Only one unclustered strain was identified simultaneously by all the systems, as Sphingomonas paucimobilis. The monitoring of the aquifer and the bottling system, and the construction of a large database with bacteria of the autochthonous flora allows the detection of alterations in the aquifer by changes in the microflora.

Bacteria↗

PubMed1995

A seven-iron ferredoxin from the thermoacidophilic archaeon Desulfurolobus ambivalens.

A seven-iron ferredoxin was isolated from aerobically grown cells of the hyperthermoacidophilic archaeon Desulfurolobus ambivalens (DSM 3772). The protein is monomeric, with an apparent molecular mass of 15 kDa and contains 7 iron atoms/molecule. The N-terminal sequence shows a large similarity (70% identity) with that of the ferredoxin isolated from the archaeon Sulfolobus acidocaldarius. The EPR characteristics in both the native (oxidized) and dithionite-reduced states of this protein allowed an unequivocal identification of a [3Fe-4S]1+/0 center, with a reduction potential of -270 +/- 20 mV, at pH 7.5. The protein also contains a [4Fe-4S]2+/1+ center with a very low reduction potential (Eo = -540 mV, pH 7.0), which yields a rhombic EPR spectrum upon reduction with sodium dithionite at high pH. The reduction potentials of both centers are slightly pH dependent between pH 6 and 9. The [3Fe-4S] ferredoxin center is able to accept electrons from pyruvate oxidase and NADH oxidase isolated from D. ambivalens. This ferredoxin is present in large amounts (at least 130 mg/kg wet cells), which allowed the unequivocal observation of oxidized [3Fe-4S] clusters in intact D. ambivalens cells.

Amino Acid Sequence↗