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Biomedical subjects

M Gomes

Publications and source records attributed to M Gomes.

At least 19 recordsLinked to original sources
PubMed2001

Mutations of the phenylalanine hydroxylase (PAH) gene in Brazilian patients with phenylketonuria.

In the present study, 115 Brazilian families with phenylketonuria (PKU), mainly from the Southeast of the country, were studied using three laboratory methods (DGGE, SSCP, and sequencing). All 13 exons of the PAH gene were analyzed, including the splicing sites and the promoter region. We identified 50 distinct mutations and characterized 91% of the mutant alleles. The five most prevalent mutations of the 50 mutations identified (50% of the PKU alleles) were IVS10nt-11G-->A (17.4%), followed by R261Q (12.2%), V388M (9.1%), R252W (6.5%), and R270K (4.8%). The other mutations were rare. The mutation spectrum included 10 novel mutations (IVS5nt-54A-->G, IVS6nt17G-->T, E205A, F240S, K274E, I318T, L321L, C357G, IVS11nt17G-->A, and S411X). To characterize the origin and distribution of the PAH alleles we determined the association between the detected mutations and the PCR/RFLP haplotypes and VNTR alleles located on the PAH gene. For those patients whose mutant alleles were detected, we calculated the correlation with pretreatment phenylalanine levels, thus establishing a genotype/phenotype correlation. The present results confirm the marked heterogeneity observed at the PAH locus and contribute to the understanding of the distribution and frequency of PKU mutations in the Brazilian population.

Brazil↗
PubMed2001

Disconjugate oculomotor learning caused by feeble image-size inequality: differences between secondary and tertiary positions.

In order to examine the minimum value of image-size inequality capable of inducing lasting disconjugacy of the amplitude of saccades, six normal emmetropic subjects were exposed for 16 min to 2% image size inequality. Subjects were seated at 1 m in front of a screen where a random-dot pattern was projected and made saccades of 7.5 and 15 deg along the horizontal and vertical principal meridians and to tertiary positions in the upper and lower field. During the training period, compensatory disconjugacy of the amplitude of the saccades occurred for the principal horizontal and vertical meridians; such increased disconjugacy persisted after training, suggesting learning. In contrast, for horizontal saccades to or from tertiary positions made in the upper and lower field, no consistent changes in the disconjugacy occurred, either during training or after the training condition. In an additional experiment, three subjects read sequences of words with the 2% magnifier in front of their dominant eye: in such a task, horizontal saccades to or from tertiary positions at the upper or lower field showed appropriate and lasting disconjugacy for two of the three subjects. We conclude that even a 2% image size inequality stimulates oculomotor learning, leading to persistent disconjugacy of saccades. The small disparity created by the image-size inequality is thus compensated by the oculomotor system rather than tolerated by the sensory system (e.g. by enlarging the Panum's area).

Aniseikonia↗
PubMed2001

Hypercoagulable syndromes: evaluation and management strategies for acute limb ischemia.

Acute limb ischemia secondary to peripheral arterial thrombosis is a relatively uncommon but ominous form of vascular accident. Select inherited and acquired hypercoagulable states appear to contribute to an initial arterial thrombosis and, more importantly, recurrent thrombotic events. Mounting interest in hypercoagulability, the increased availability of hypercoagulable state "profiles," and enhanced ability to identify an abnormality in tested patients have promoted widespread testing. Unfortunately, widespread testing has had a limited beneficial impact on the management of acute limb ischemia. Ideally, costly and specialized testing should be limited to situations in which the results will have a tangible impact on patient care. Clear goals of testing should be determined before testing is performed. This article addresses a practical approach to hypercoagulable state testing in patients with acute limb ischemia with a focus on abnormalities that impact patient management.

Acute Disease↗
PubMed2000

Effects of inter-alpha-inhibitor and several of its derivatives on calcium oxalate crystallization in vitro.

The bikunin peptide chain of the protease inhibitor inter-alpha-inhibitor (IalphaI) has been reported to be an inhibitor of calcium oxalate (CaOx) crystallization, and hence has been proposed as having a role in CaOx kidney stone formation. However, further experimental evidence is required to assess if fragments of IalphaI other than bikunin may play a role in the regulation of crystallization events in stone formation. The aim of the present study was to assess the effects of IalphaI and several of its derivatives on CaOx crystallization in a seeded inorganic system and to compare these effects with those of a known inhibitor of crystallization, prothrombin. IalphaI was purified from a preparation of human plasma and fragmented by alkaline hydrolysis, and two of its peptide chains, bikunin and heavy chain 1 (H1), were purified further by HPLC. Their purity was confirmed by SDS/PAGE. Using Coulter counter and [(14)C]oxalate analysis and scanning electron microscopy, IalphaI, its H1 chain and bikunin from urine and from plasma were shown to be relatively weak inhibitors of CaOx crystallization in vitro at expected physiological concentrations. It was concluded that members of the IalphaI family may not be as important in kidney stone formation as has been generally proposed, although further studies are required before a possible role for IalphaI and its fragments in stone formation can be unambiguously discounted.

Alpha-Globulins↗
PubMed1998

Epidemiological control of tuberculosis in pelotas, rio grande do sul, brazil: treatment compliance

This study assesses risk factors for treatment noncompliance by patients registered with the Tuberculosis Control Program who live in the urban area of Pelotas, Rio Grande do Sul State. The study lasted from June 1994 to December 1995. All new cases diagnosed as pulmonary tuberculosis in the 20-80-year age bracket were monitored by the Tuberculosis Unit, hub of the tuberculosis control program in Pelotas. All patients was monitored from time of diagnosis through end of treatment, six months later. Patients answered a standard questionnaire. From June 1994 to June 1995, 152 cases were recorded, with some 20% treatment noncompliance. We observed no significant association between noncompliance and employment status for head-of-family, age, gender, alcoholism, or presence of symptoms, while the only risk factor significantly associated with noncompliance was non-white skin color, probably due to the study's weak power as a function of sample size.

Journal Article↗
PubMed1998

What are the World Health Organization's strategies for meeting regulatory requirements? A case study of artesunate.

The basic scope of WHO for developing new drugs or a new indication, is that of responding to a public health need, at an affordable price. This paper describes the approach taken by the organisation for the development of rectal artesunate and the special arrangements and approach which have made this possible for the WHO to meet regulatory requirements. Regulatory submission is planned in Europe and the USA, harmonising the submission, registration and labelling, and this precedent may constitute a worldwide reference for the deployment of the drug. The approach is novel, fast, and unbureaucratic, and can be applied to other drugs meeting a live-saving need.

Administration, Rectal↗
PubMed1998

What role can public health institutions play in drug development for the poor? A case study of artesunate.

Although the strategy of artesunate development was orchestrated from within WHO's Special Programme for Research and Training in Tropical Diseases, it relies heavily upon an alliance of scientist, laboratories, industry, regulators and ministries of health to ensure the public health outcome. This development strategy has transformed the way in which WHO does business, both within and outside the Organization. In essence, each and every player has rallied in the challenge to reduce the discrepancy between need and availability of a drug that can has the potential to reduce mortality form the disease.

Africa↗
PubMed1998

Interventions to improve the use of antimalarials in south-east Asia: an overview.

There are few drugs for malaria, and those which are available for use are subject to rapid development of resistance. Curiously, little effort has been made to improve drug use in malaria-endemic countries and to assess the benefits of such improvements. Advances can be made in public understanding of the value of ingesting a full regimen of antimalarials, in order to achieve complete cure, and in improving simple technologies (blister packaging) to achieve the same result. Better efforts can be made to reduce the availability of fake or substandard drugs in the marketplace. In this article, we describe the outcome of a concerted effort to improve drug compliance and drug quality in an area of multidrug resistance for malaria. These research efforts, guided by the Task Force for Improved Use of Antimalarials, characterized the problems in drug compliance in South-East Asia, and developed interventions to improve drug use in the various countries. Interventions involved drug packaging, public information campaigns, and assessments of drug quality. Results show that blister packaging worked best to improve drug compliance and that the increased cost of packaged medication did not limit its use. Drug quality was a major problem in unregulated countries and should be improved.

Antimalarials↗
PubMed1998

More crops, more disease?

The intensity of disease transmission by insect vectors may be influenced by developments in agriculture and forestry. The author illustrates what can happen with special reference to projects in Thailand and Ethiopia which increased the incidence of malaria, and to the introduction of a new variety of coffee in Colombia, as a result of which the incidence of leishmaniasis among plantation workers decreased. Development programmes need to take predictable disease outcomes fully into account.

Agriculture↗
PubMed1997

Profile of Morong, Bataan, an area of low malaria endemicity in the Philippines.

A malaria study area in the Philippines is described. It consists of the municipality of Morong, Bataan on the Island of Luzon. In January 1992, the population was 19454 in 106 villages located on a narrow coastal plain, or in valleys of streams running from the mountainous interior. This is an area of low level but persistent seasonal transmission of malaria with approximately one thousand cases reported each year, mainly from February to July. In spite of the low level of malaria, it is apparently quite stable. The study site has been used to investigate parameters leading to stable malaria. Hypotheses tested were that there was substantial under reporting of cases; that there was strain specific immunity stabilising the incidence of malaria and that malaria transmission in this area is highly localised in small regions with a high enough malaria prevalence to account for the year to year stability. The study plan included cross sectional surveys of parasite prevalence and seropositivity, longitudinal surveys, passive case detection, entomological surveys, anthropological surveys to assess knowledge of malaria and documentation of the health-seeking behaviour of the population.

Adolescent↗
PubMed1995

Autologous blood donation in cardiac patients.

Despite the advantages of autologous blood transfusion, doubt still remains about its safety in cardiac patients. We report our experience with 439 cardiac patients who donated a total of 1692 units of blood before coronary, valvular, or congenital cardiac operations. During the collections, patients were continuously monitored with ECG, blood pressure, and heart rate. In 22 collections we observed vasovagal reactions, which represents an incidence of 1.3% of the total number of collections. The patients recovered quickly and only in 3 cases was volume replacement with saline needed. There were no other complications which could be related to the preoperative autologous donation program. We feel that, with careful selection of the patients and of the circumstances surrounding the collection of blood, autologous blood donation in cardiac patients is a safe and beneficial experience.

Adolescent↗
PubMed1994

The reliability of Hickman catheter blood for the assessment of activation markers of coagulation and fibrinolysis in patients with hematological malignancies.

We studied the reliability of Hickman catheter (HC) blood for the determination of activation markers of coagulation and fibrinolysis in 14 patients with hematological malignancies. 10 of 22 HC samples were contaminated with heparin, probably as a consequence of our institutional antithrombotic catheter care, and withdrawn from statistical analysis. Prothrombin activation fragment F1.2, thrombin-antithrombin III complexes, soluble fibrin, degradation products of fibrinogen and fibrin, total degradation products, alpha 2-antiplasmin and antithrombin III levels withdrawn from Hickman catheters did not differ significantly from peripheral venous blood samples. Fibrinogen levels were slightly but significantly higher in peripheral venous blood samples. We conclude that Hickman catheter blood gives reliable results for the determination of activation markers of coagulation and fibrinolysis in patients with hematological malignancies, but may be less useful in clinical practice due to frequent heparin contamination.

Adolescent↗
PubMed1994

Symptomatic identification of malaria in the home and in the primary health care clinic.

In endemic areas in the absence of microscopy, the WHO case definition of malaria is the presence or a history of fever without other obvious cause. Yet there is little empirical evidence on the accuracy, predictability and reliability of clinical signs and symptoms for diagnosing malaria within different endemic settings. Studying patients in endemic communities in the Philippines, we found that fever alone did not discriminate well for malaria. In contrast, a sequential occurrence of fever, chills and/or sweating, or a combination of all three symptoms was a good general predictor of the disease. However, the place of diagnosis and observation (home or clinic), age, and season affected the positive predictive values obtained. Specificities and positive predictive values were greatest (over 80%) for those at most risk--children under 9 years of age in highly endemic communities--and were most reliable when the diagnosis was made at home. Predictive values were also greatest during the season when childhood acute lower respiratory infections in the study area increase. The good predictability of clinical signs and symptoms for high-risk groups suggests that simple protocols can be developed for the management of malaria in endemic areas of the Philippines.

Adolescent↗