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I Ribeiro

Publications and source records attributed to I Ribeiro.

At least 19 recordsLinked to original sources
PubMed2005

Isolation, purification and characterization of glycosaminoglycans in the fluids of the mollusc Anodonta cygnea.

The isolation, purification and characterization of Anodonta cygnea haemolymph, and extrapallial fluid glycosaminoglycans (Gags), which have high calcium affinity, were carried out in order to better understand the process of nacreous shell biomineralization. Our results show the existence of two different Gags with similar contents in the two fluids, throughout the year, but with significant seasonal variations for both. In the winter months, we identified by electrophoresis, only one kind of Gag chain (hyaluronic acid) while two different Gags (hyaluronic acid and heparan sulphate-like) from both fluids of A. cygnea were found in summer months. Quantification showed the total Gag fractions of both fluids in average, at their highest concentration (79.8 mg/L) in the highest calcification summer period. In contrast, the period of the year with the lowest concentration of total Gags (54.6 mg/L) occurred during the winter when calcification is reduced. This significant decrease between seasons is correlated mainly with the sulphated fraction, being 37.1 mg/L in the summer while only 9.2 mg/L in the winter haemolymph. The present data suggest that a heparan sulphate-like Gag has a relevant role in the biomineralization mechanisms acting as the calcium carbonate nucleator in the shell.

Animals↗
PubMed2004

Efficacy of rectal artesunate compared with parenteral quinine in initial treatment of moderately severe malaria in African children and adults: a randomised study.

BACKGROUND: Many patients with malaria of increasing severity cannot take medicines orally, and delay in injectable treatment can be fatal. We aimed to assess the reliability of absorption, antimalarial efficacy, and tolerability of a single rectal dose of artesunate in the initial management of moderately severe falciparum malaria. METHODS: 109 children and 35 adults were randomly assigned to rectal artesunate (single dose of about 10 mg/kg) or parenteral quinine treatment (10 mg/kg at 0, 4, and 12 h). The primary endpoint was the proportion of patients with peripheral asexual parasitaemia of less than 60% of that at baseline after 12 h. Secondary endpoints were clinical response and concentrations of drug in plasma. Analysis was by intention-to-treat. FINDINGS: All artesunate-treated patients had pharmacodynamic or pharmacokinetic evidence of adequate drug absorption. 80 (92%) of 87 artesunate-treated children had a 12 h parasite density lower than 60% of baseline, compared with three of 22 (14%) receiving quinine (relative risk 0.09 [95% CI 0.04-0.19]; p<0.0001). In adults, parasitaemia at 12 h was lower than 60% of baseline in 26 (96%) of 27 receiving artesunate, compared with three (38%) of eight receiving quinine (relative risk 0.06 [0.01-0.44]; p=0.0009). These differences were greater at 24 h. Clinical response was equivalent with rectal artesunate and parenteral quinine. INTERPRETATION: A single rectal dose of artesunate is associated with rapid reduction in parasite density in adults and children with moderately severe malaria, within the initial 24 h of treatment. This option is useful for initiation of treatment in patients unable to take oral medication, particularly where parenteral treatment is unavailable.

Administration, Rectal↗
PubMed2001

Niemann-Pick type C disease: NPC1 mutations associated with severe and mild cellular cholesterol trafficking alterations.

Niemann-Pick type C disease (NPC) is a rare neurodegenerative disorder characterised by lysosomal/late endosomal accumulation of endocytosed unesterified cholesterol and delayed induction of cholesterol homeostatic reactions. The large majority of mutations in the NPC1 gene described thus far have been associated with severe cellular cholesterol trafficking impairment (classic biochemical phenotype, present in about 85% of NPC patients). In our population of 13 unrelated NP-C1 patients, among which 12 were of Portuguese extraction, we observed an unusually large proportion of families presenting mild alterations of intracellular cholesterol transport (variant biochemical phenotype), without strict correlation between the biochemical phenotype and the clinical expression of the disease. Mutational studies were carried out to compare molecular lesions associated with severe and mild cholesterol traffic impairment. Levels of NPC1 protein were studied by Western blot in cultured fibroblasts of four patients with homozygous mutant alleles. Ten novel mutations were identified (Q92R, C177Y, R518W, W942C, R978C, A1035V, 2129delA, 3662delT, IVS23+1 G>A and IVS16-82 G>A). The mutational profile appeared to be correlated with the biochemical phenotype. Splicing mutations, I1061T and A1035V, corresponded to "classic" alleles, while three missense mutations, C177Y, R978C and P1007A, could be defined as "variant" alleles. All "variant" mutations described so far appear to be clustered within the cysteine-rich luminal loop between TM 8 and 9, with the remarkable exception of C177Y. The latter mutant allele, at variance with P1007A, was correlated to a decreased level of NPC1 protein and a severe course of the disease, and disclosed a new location for "variant" mutations, the luminal loop located at the N-terminal end of the protein.

Adult↗
PubMed2000

Linkage analysis for major histocompatibility complex-related genetic susceptibility in familial chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) shows evidence of familial aggregation, but the genetic basis is poorly understood. The existence of a linkage between HLA and Hodgkin lymphoma, another B-cell disorder, coupled with the fact that CLL is frequently associated with autoimmune disease, led to the question of whether the major histocompatibility complex (MHC) region is involved in familial cases of CLL. To examine this proposition, 5 microsatellite markers on chromosome 6p21.3 were typed in 28 families with CLL, 4 families with CLL in association with other lymphoproliferative disorders, and 1 family with splenic lymphoma with villous lymphocytes. There was no evidence of linkage in these families to chromosome 6p21.3. The best estimates of the proportions of sibling pairs with CLL that share 0, 1, or 2 MHC haplotypes were not significantly different from the null expectation. This implies that genes within the MHC region are unlikely to be the major determinants of familial CLL. (Blood. 2000;96:3982-3984)

Adult↗
PubMed1999

Linkage analysis for ATM in familial B cell chronic lymphocytic leukaemia.

B cell chronic lymphocytic leukaemia (CLL) shows evidence of familial aggregation, but the inherited basis is poorly understood. Mutations in the ATM gene have been demonstrated in CLL. This, coupled with a possibly increased risk of leukaemia in relatives of patients with Ataxia Telangiectasia, led us to question whether the ATM gene is involved in familial cases of CLL. To examine this proposition we typed five markers on chromosome 11q in 24 CLL families. No evidence for linkage between CLL and ATM in the 24 families studied and the best estimates of the proportion of sibling pairs that share no, one or both haplotypes at ATM were not different from their null expectations. This would imply that ATM is unlikely to make a significant contribution to the three-fold increase in risk of CLL seen in relatives of patients.

Adult↗
PubMed1996

A fluorescent vesicle system for the measurement of blood velocity in the choroidal vessels.

BACKGROUND AND OBJECTIVE: Evaluation of the pathophysiologic mechanisms involved in the choroidal circulation is difficult because of the presence of the retinal pigment epithelium. The authors have developed a technique for measuring blood velocity in individual choroidal vessels using the scanning laser ophthalmoscope and intravenously injected indocyanine green encapsulated in multilamellar vesicles. In this report, the authors describe their attempts to measure choroidal blood velocity in three different regions of the choroid of the primate eye. MATERIALS AND METHODS: A video-to-digital processor was used to digitize the video images of the choroid of a monkey at a sample rate of 1/30 of a second. The blood velocity in the selected choroidal vessel segments was calculated by measuring the distance the liposome traveled in a given time. RESULTS: The average blood velocities were 5.16 mm/s under the macula, 4.04 mm/s in the vortex vein system, and 2.03 mm/s in the choroidal circulation nasal to the optic nerve. CONCLUSION: This technique is an effective method of measuring blood velocity in a primate model and has several important advantages compared with the dye dilution technique.

Animals↗
PubMed1993

Ondansetron in the treatment of nausea and vomiting induced by chemotherapy. Portuguese Ondansetron Study Group.

One-hundred and forty-five chemotherapy patients receiving cisplatin- and non-cisplatin-containing regimens participated in an open evaluation of ondansetron, a 5-HT3 receptor antagonist, in the prophylaxis of acute and delayed nausea and vomiting. The study had two groups of patients, one receiving cisplatin-containing regimens (Group A) and the other, non-cisplatin-containing regimens (Group B). There were 51 patients recruited to Group A. Ondansetron was given to these patients at a dose of 8 mg intravenously 15 min before chemotherapy, followed by an intravenous infusion for 24 h (1 mg/h), or 8 mg intravenously 4 and 8 h after the start of cisplatin, followed by 8 mg orally three times/day for 5 days. Ninety-four patients were recruited to Group B: these patients received ondansetron at a dose of 8 mg intravenously immediately before chemotherapy or 8 mg orally 1-2 h prior to it, and 8 mg orally three times/day for 3-5 days. For acute emesis (first 24 h), complete control was achieved in 79.5% of Group A patients and in 78.1% of Group B. For delayed emesis (days 2-5), 79.7% of Group A patients and 84.6% of Group B were completely protected during the entire study period. Nausea was also well controlled with ondansetron; 83.2% (Group A) and 86.5% (Group B) reported only mild nausea or no nausea at all. Ondansetron was effective in the control of both cisplatin- and non-cisplatin-induced emesis and well tolerated without any serious drug-related adverse events.

Adolescent↗
PubMed1993

Eosinophilic leukaemia with trisomy 8 and double gammopathy.

Prolonged eosinophilia of unknown cause has generally been described as the hypereosinophilic syndrome, and is characterised by peripheral blood and bone marrow infiltration and frequent multisystem disease. The nature of this disorder has been questioned, and the clinical features are quite variable, suggesting its heterogeneity and probable neoplastic aetiology. A patient with severe eosinophilia, karyotype abnormalities, serum gammopathy and massive organ disease is reported. The clinical course was aggressive despite cytoreduction of eosinophils and terminated in multisystem failure. These findings are consistent with a diagnosis of eosinophilic leukaemia, and it is suggested that chromosome and cell culture studies might be useful in the early diagnosis of this controversial entity.

Aged↗
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↗
PubMed1991

Functional and morphological features of isolated hepatocytes preserved in University of Wisconsin solution.

Although several studies suggest that hepatic graft failure after cold ischemia results from nonparenchymal cell damage, other data indicate that hepatocellular ATP content is significantly correlated with the transplantation success rate. In this study, we have conducted a systematic investigation of various aspects of cell viability and function of isolated hepatocytes stored at 4 degrees C for 24 and 48 hr in either University of Wisconsin solution or Hanks' HEPES buffer, a control solution clinically unsuitable for organ preservation. After 24 hr, hepatocytes stored in Hanks' HEPES buffer had viability (measured by trypan blue exclusion and ALT and lactic dehydrogenase leakage), transport function (measured by 22Na+ and [3H]taurocholate uptake) and cell size similar or only slightly altered when compared with freshly isolated and University of Wisconsin solution-stored hepatocytes. ATP content was decreased in both groups; however, the reduction was much greater in Hanks' HEPES buffer-stored cells. Furthermore, ATP regenerating capacity was greatly reduced in Hanks' HEPES buffer- stored but not in University of Wisconsin solution-stored hepatocytes. By 48 hr viability and function of Hanks' HEPES buffer-stored hepatocytes were decreased; University of Wisconsin solution afforded partial protection. When examined by light and electron microscopy, cells stored in both University of Wisconsin solution and Hanks' HEPES buffer for 24 hr appeared essentially normal except for the presence of numerous membrane blebs in the Hanks' HEPES buffer group. Tissue sections of livers preserved in Hanks' HEPES buffer but not in University of Wisconsin solution revealed the presence of extensive amounts of blebs in the sinusoidal lumen and loss of endothelial elements.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1990

Controversies in posttraumatic epilepsy.

In civilian accidents the factors involved in the origin of posttraumatic epilepsy are controversial. In this study of 506 consecutive head trauma patients and 101 epileptic patients developing seizures after head trauma, we have examined the importance of the duration of coma, type of seizure and drug therapy, time to first seizure, age and focal lesions and compared our results with the literature. The importance is stressed of focal lesions and of neurological deficits for the origin of posttraumatic seizures.

Adolescent↗
PubMed1990

[Efficacy of the electrocardiographic diagnosis of left ventricular hypertrophy on the basis of gender].

STUDY OBJECTIVE: To determine the efficacy of electrocardiographic criteria of Left Ventricular Hypertrophy (RVL greater than 11 mm, SVE3 + RVL greater than 20 mm in females and greater than 28 mm in males, SV1 + RV6 or SV2 + RV5) in hypertensive patients according to sex. DESIGN: Retrospective study. Gold standard M mode echocardiography. SETTING: Pulido Valente Hospital Department of Cardiology (Lisbon). PATIENTS: 56 hypertensive patients (age 55.1 s.d. 11.6), 27 females and 29 males, with LVH by echocardiographic Left Ventricular Mass Index (LVMI) greater than 110 g/m2 in woman and greater than 134 g/m2 in men, respectively 10 and 19 patients. The LVMI was calculated by the formula of the American Society of Echocardiography modified by Devereux. RESULTS: The LVMI was smaller in females than in males (P = 0.007). The Cornell Criteria had the greatest efficacy in woman and the Sokolow criteria satisfactory efficacy but in man. The electrocardiogram (1 of the 4 criteria positive) had low diagnostic efficacy in woman. CONCLUSIONS: We concluded that echocardiogram is the best non-invasive diagnostic tool of Left Ventricular Hypertrophy in hypertensive females and is necessary to adjust and choose the electrocardiographic Left Ventricular Hypertrophy criteria according to sex.

Adult↗
PubMed1989

Breast-feeding and fertility in Macau.

That fact that only a small percentage of women in Macau breast-feed induced the need to investigate this attitude. In collaboration with the Maternal & Child Health Division of the W.H.O., Geneva, it was decided that a methodology which had already been applied in other places should be used to investigate the relation between breast-feeding and fertility. In this way, information was obtained about the situation, within a given period of time which permitted a description of the duration of amenorrhea due to breast-feeding, as well as the patterns of frequency and duration of breast-feeding.

Adolescent↗