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Biomedical subjects

A Nunes

Publications and source records attributed to A Nunes.

At least 19 recordsLinked to original sources
PubMed2003

The psychosocial determinants of hypertension.

AIM: To present currently available evidence on the role that adverse psychosocial factors play in the pathogenesis of hypertension. The specific objectives of the review were to (1) provide a picture of what is known about the relationship between psychosocial factors and hypertension, (2) summarize the major methodological and conceptual pitfalls, and (3) identify gaps in the literature and suggest areas for future research. DATA SYNTHESIS: The scope of the literature review was adults and the literature published since 1990 (acknowledging that some articles published earlier would need to be taken into account). A number of journal searches were carried out. They included Medline, PsychInfo, and SocioFile, with keywords, such as hypertension, blood pressure, psychosocial, psychological, social, acculturation, occupation, socio-economic status, social class, education, depression, anger, and anxiety. The search included articles related to hypertension in developed countries and was limited to studies in the English language. CONCLUSION: A growing body of evidence supports the thesis that psychosocial factors play a role in the pathogenesis for hypertension.

Anger↗
PubMed2002

Endosonographic Doppler-guided manometry of esophageal varices: experimental validation and clinical feasibility.

BACKGROUND AND STUDY AIMS: The risk of variceal bleeding cannot be accurately predicted using endoscopy alone. Although variceal pressure has been demonstrated to be a major determinant for the rupture of esophageal varices, direct determination by needle puncture is unsuitable for routine clinical use. Due to their operator-dependency, current noninvasive endoscopic methods for determination of variceal pressure have not gained wide acceptance. We have developed a new method of measuring variceal pressure, using endoscopic power Doppler imaging to monitor the manometry of esophageal varices. The aims of this study were to test in vitro the accuracy of Doppler-guided manometry and to assess the clinical feasibility of this method. MATERIALS AND METHODS: Experimental validation of this technique was performed using an in vitro model of artificial varices of different sizes. A linear-array endosonography (EUS) probe with power Doppler capability was used to assess flow in the varices and a balloon for manometry of esophageal varices was attached to the tip of the probe. Pressure readings were made at the time of disappearance of the Doppler signal during variceal compression by the balloon. Linear regression analysis was used to compare the results of Doppler-guided and direct intraluminal pressure measurement in the artificial varices. Variceal pressure was then measured with this technique in 28 patients with portal hypertension and esophageal varices without previous bleeding, and the results were compared with portal pressure assessed according to the hepatic vein pressure gradient (HVPG). RESULTS: In vitro studies demonstrated a good correlation between the pressure measured with Doppler monitoring and the actual intravariceal pressure (r > or = 0.922; P < 0.001). The determination of variceal pressure with this method was technically successful in 26/28 patients (93 %). The intraoperator variance was 9.3 +/- 8.6 %. Overall, the mean variceal pressure was significantly lower than the mean HVPG (21.2 +/- 5.3 mmHg vs. 24.3 +/- 7.8 mmHg; P < 0.01). Variceal pressure and portal pressure (as assessed by the HVPG) correlated significantly (r = 0.64; P < 0.001). CONCLUSIONS: Our preliminary results indicate that EUS Doppler-guided manometry of esophageal varices is feasible and accurate. This technique may become a more reliable method for noninvasive measurement of variceal pressure and warrants further investigation.

Endosonography↗
PubMed1999

Fused bicyclic Gly-Asp beta-turn mimics with specific affinity for GPIIb-IIIa.

Disubstituted isoquinolones 2 and 3 have affinity for GPIIb-IIIa and represent leads for further structural evaluation. Structure-activity studies centered on the bicyclic beta-turn mimic contained in these molecules indicated that this moiety could accommodate a variety of modifications. Specifically, monocyclic, 6, 5-bicyclic, and 6,7-bicyclic structures provide compounds with affinity for GPIIb-IIIa. Within the 6,6-series, isoquinoline, tetralin, tetralone, and benzopyran nuclei yield potent antagonists that are specific for GPIIb-IIIa. Attachment of the arginine isostere (benzamidine) to the supporting nucleus can be accomplished with an ether or amide linkage, although the latter enhances activity. Several compounds in this series provided measurable blood levels after oral dosing. Conversion of the acid moiety in these molecules to an ester generally provided compounds which gave greater systemic exposure after oral administration. Absolute bioavailabilities in the rat for the ethyl ester prodrug derivatives of the tetralin, tetralone, and benzopyran analogues of 3 were 28%, 23%, and 24%, respectively.

Administration, Oral↗
PubMed1999

Disparate phylogeographic patterns of molecular genetic variation in four closely related South American small cat species.

Tissue specimens from four species of Neotropical small cats (Oncifelis geoffroyi, N = 38; O. guigna, N = 6; Leopardus tigrinus, N = 32; Lynchailurus colocolo, N = 22) collected from throughout their distribution were examined for patterns of DNA sequence variation using three mitochondrial genes, 16S rRNA, ATP8, and NADH-5. Patterns between and among O. guigna and O. geoffroyi individuals were assessed further from size variation at 20 microsatellite loci. Phylogenetic analyses using mitochondrial DNA sequences revealed monophyletic clustering of the four species, plus evidence of natural hybridization between L. tigrinus and L. colocolo in areas of range overlap and discrete population subdivisions reflecting geographical isolation. Several commonly accepted subspecies partitions were affirmed for L. colocolo, but not for O. geoffroyi. The lack of geographical substructure in O. geoffroyi was recapitulated with the microsatellite data, as was the monophyletic clustering of O. guigna and O. geoffroyi individuals. L. tigrinus forms two phylogeographic clusters which correspond to L.t. oncilla (from Costa Rica) and L.t. guttula (from Brazil) and which have mitochondrial DNA (mtDNA) genetic distance estimates comparable to interspecific values between other ocelot lineage species. Using feline-specific calibration rates for mitochondrial DNA mutation rates, we estimated that extant lineages of O. guigna diverged 0.4 million years ago (Ma), compared with 1.7 Ma for L. colocolo, 2.0 Ma for O. geoffroyi, and 3.7 Ma for L. tigrinus.

Alleles↗
PubMed1999

Ticlopidine-induced prolonged cholestasis: a case report.

We report a case of ticlopidine-induced prolonged cholestasis in a 60-year-old man with no previous hepatobiliary disease who presented with sudden right upper abdominal pain, jaundice and pruritus three months after starting ticlopidine therapy. Other drugs taken by the patient were not considered probable causes. The diagnostic evaluation showed no biliary obstruction and other possible causes of intra-hepatic cholestasis were excluded. The liver biopsy showed a cholestatic hepatitis with bile duct damage. The disease ran a severe and protracted course, but symptoms and jaundice eventually subsided five months after drug withdrawal. More than a year later, relevant abnormalities of liver function tests consistent with anicteric cholestasis still persist, fulfilling criteria for a minor form of drug-induced prolonged cholestasis. This syndrome has been reported infrequently in relation to several drugs, mainly chlorpromazine, and only once with ticlopidine.

Cholestasis↗
PubMed1999

Subtle mutagenesis by ends-in recombination in malaria parasites.

The recent advent of gene-targeting techniques in malaria (Plasmodium) parasites provides the means for introducing subtle mutations into their genome. Here, we used the TRAP gene of Plasmodium berghei as a target to test whether an ends-in strategy, i.e., targeting plasmids of the insertion type, may be suitable for subtle mutagenesis. We analyzed the recombinant loci generated by insertion of linear plasmids containing either base-pair substitutions, insertions, or deletions in their targeting sequence. We show that plasmid integration occurs via a double-strand gap repair mechanism. Although sequence heterologies located close (less than 450 bp) to the initial double-strand break (DSB) were often lost during plasmid integration, mutations located 600 bp and farther from the DSB were frequently maintained in the recombinant loci. The short lengths of gene conversion tracts associated with plasmid integration into TRAP suggests that an ends-in strategy may be widely applicable to modify plasmodial genes and perform structure-function analyses of their important products.

Animals↗
PubMed1998

Diet and feeding ecology of Ateles belzebuth belzebuth at Maracá Ecological Station, Roraima, Brazil.

The diet and feeding behaviour of habituated group of free-ranging spider monkeys (Ateles belzebuth belzebuth) were studied from 1987 to 1989. Their dietary patterns were analysed in relation to the temporal and spatial distribution of food resources. The results indicate that ripe fruit was regularly eaten throughout the study period and that diet composition was significantly related to the overall availability of ripe fruit sources.

Animals↗
PubMed1998

[Importance of J. Brazy's neurobiological index. Prediction of the number and severity of complications in very low birth weight infants].

The objective of this study was to evaluate the neurodevelopment outcome of Very-Low-Birth-Weight Infants (VLBW), between 1987 and 1993, and correlate these findings with J.Brazy's Neurobiologic Risk Score (NBRS). The minimum corrected age at follow-up was 12 months. The neurodevelopmental assessment was performed using Mary Sheridan and Ruth Griffiths scales, Auditory and Visual Brainstem Evoked Responses and Stycar test. The NBRS was applied to 77 children. According to the score, three groups of risk were defined: Low < or = 4; Intermediate 5-7; High > or = 8. We obtained the following results: children with NBRS < 4, 20% had handicaps (5% of which major); children with NBRS 5-7, 41% had handicaps (23% of which major); in children with NBRS > 8, 95% had handicaps (80% of which major). The incidence of handicaps, (all grades included) was 71.4% for those weighing less than 1000 gr at birth, and 39.2% for those weighing 1000-1499 gr at birth. Major handicaps, mainly motor deficits, occurred in 26.8% of VLBW infants and minor to moderate handicaps were observed in 18.3% of patients in this group. These results were compared to J.Brazy's originals. We concluded that the NBRS, which is simple and objective to perform, is a good predictor of subsquent abnormal development in VLBW infants, allowing the infant's integration as soon as possible in high-risk follow-up programs, to place as soon as possible.

Developmental Disabilities↗
PubMed1997

Non-peptide RGD surrogates which mimic a Gly-Asp beta-turn: potent antagonists of platelet glycoprotein IIb-IIIa.

Cyclic heptapeptide 1, which contains an Arg-Gly-Asp sequence, has good affinity for the platelet receptor GPIIb-IIIa and was chosen for study by 1H NMR techniques. The key RGD sequence of this molecule was found to reside in a conformationally defined type II' Gly-Asp beta-turn, and this information was used in the design of simple non-peptide RGD mimics. Disubstituted isoquinolones, bearing an acidic side chain at position 2 and a basic side chain at position 6, were prepared and were found to have modest affinity for GPIIb-IIIa. Systematic modification of the basic residue contained in these molecules yielded compounds with high affinity for GPIIb-IIIa.

Aspartic Acid↗
PubMed1996

Study of the liver changes occurring in preeclampsia and their possible pathogenetic connection with acute fatty liver of pregnancy.

OBJECTIVE: The objective of the present study was to investigate liver involvement in preeclampsia on the basis of clinical, laboratory, and histological data and to detect a possible connection with fatty liver of pregnancy by the determination of microvesicular fatty infiltration of the liver. METHODS: The authors studied the liver changes in 10 patients with preeclampsia, observing the clinical and laboratory alterations, the macroscopic liver surface features by laparoscopy, and the presence of microvesicular fatty infiltration by specific lipid staining of hepatic tissue collected by needle biopsy. RESULTS: Macroscopy of the liver surface disclosed some degree of subcapsular liver hemorrhage in all cases; however, the hemorrhage was not related to the clinical and histological severity of the disease. Microvesicular fat droplets were observed in all patients, and the intensity of the fat deposition was not related to pressor levels, laboratory alterations, or the evolution of preeclampsia. CONCLUSIONS: The presence of fatty liver infiltration in all patients studied supports the idea that preeclampsia and acute fatty liver of pregnancy could be components of the same pathologic spectrum, with a probable, but still unproved, pathogenetic connection. The deficiency of the long chain 3-hydroxyacyl-coenzyme A dehydrogenase activity may be the determining factor in the evolution of the disease.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1995

Foraging and ranging patterns in white-bellied spider monkeys.

Ranging and foraging patterns observed during a field study of the behavioral ecology of Ateles belzebuth belzebuth are analysed in the context of temporal and spatial variation in the distribution of plant resources at the study site. The study group exhibited two basic patterns of foraging behaviour and habitat exploitation, which appeared to correlate with the observed variation in resource availability. During the dry season, when the relative abundance of fruit decreased, the spider monkeys ranged over a smaller area, repeatedly visiting a few intensively used fruiting and sleeping trees. As fruit abundance increased during the course of the wet season, the study group expanded its range, and both the daily path length and the number of fruiting trees visited increased daily. These patterns are analysed and evaluated in relation to foraging strategies.

Animal Feed↗
PubMed1989

[Lymphomatoid granulomatosis vs. leprosy].

Lymphomatoid granulomatosis (LYG) was first described by LIEBOW, A.A. et al. Histologically is characterized by an lymphohistiocytic infiltrate with granulomatous features, polymorphous and pleiomorphic, angiocentric and angiodestructive and mainly involves lungs, skin, kidneys and CNS. LYG does not involves spleen, bone marrow and lymph nodes. Presently there is a concept that LYG is an angiocentric variant of T-cell peripheral lymphoma and histologically indistinguishable from polymorphic reticulosis of the upper airways (midline lethal granuloma). The prognosis for patients with LYG is guarded. Treatment with cyclophosphamide and prednisone may lead to remission in early cases. The skin is the most commonly involved extrapulmonary organ and in 13 to 34% of patients the skin lesions precede the pulmonary involvement. The clinical features of the skin lesions may vary, but frequently they are erythematous and violaceous plaque lesions or annular infiltrated lesions with central clearing. The differential diagnosis of these lesions includes granuloma annular, sarcoidosis and Hansen's disease. Since Hansen's disease is common among us and that LYG includes involvement of cutaneous branches and nerve trunks, with hypo or hyperesthesia in skin lesions and paresthesia of limbs, it is of utmost importance to make differential diagnosis. This report deals with a 42 years old male with cutaneous lesions of LYG and concomitant pulmonary and systemic manifestations. A first skin biopsy roughly suggested tuberculoid leprosy due to a granulomatous and perineural localization of cellular infiltrate. The patient died on respiratory insufficiency and the necropsy findings of the skin revealed important histological modifications. The infiltrate was more polymorphous, pleiomorphic and angiocentric. The same histological features were found in CNS, heart, digestive tract, liver, prostate, testes, lungs and kidneys. In these two last organs there were large nodules made of the characteristic cellular infiltrate and also large necrotic areas.

Adult↗