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Biomedical subjects

J Brito

Publications and source records attributed to J Brito.

17 recordsLinked to original sources
PubMed2006

Prevalence and characteristics of smoking in primary healthcare workers in Iquique, Chile.

OBJECTIVE: To determine the prevalence and characteristics of the smoking habits of primary healthcare workers in Iquique, Chile. STUDY DESIGN: Cross-sectional study through a survey of all personnel working in primary health care in Iquique, Chile. METHODS: The following variables were investigated: biodemographical characteristics and aspects of smoking, knowledge of the adverse effects of smoking, and some lifestyle factors. RESULTS: Among the study population, a high prevalence of smokers was found (37%) and a further 26% were ex-smokers. The smokers were predominantly practical nurses, female, aged 25-45 years and married. The only significant relationship was between age and smoking habit (P=0.02), with smoking prevalence among younger groups being very high (56%). There was a high level of awareness about the adverse effects of smoking and its addictiveness (99 and 93%, respectively). Forty-three percent of participants had been smoking for more than 15 years, and the main reasons for smoking were 'social consumption' and 'stress' (36 and 29%, respectively). Thirty-two percent of the ex-smokers ceased smoking for discomfort or health reasons. There were no differences between smokers and ex-smokers with respect to participation in sports or working shifts. Fifty-two percent of those surveyed reported they they were annoyed when others smoked near them. CONCLUSION: This study revealed a high prevalence of smoking, particularly among practical nurses. Regarding attitudes to health, a dichotomy between knowledge and behaviour was found in this group. In pursuing the commitment to smoking cessation in healthcare personnel, a deeper review of cultural issues and motivation should be considered.

Adult↗
PubMed2004

Bismuth citrate in the quantification of inorganic phosphate and its utility in the determination of membrane-bound phosphatases.

This paper describes a rapid and sensitive method to determine inorganic phosphate, even in the presence of labile organic phosphate compounds and large quantities of proteins. The method eliminates the use of sodium arsenite, a highly toxic compound, substituting bismuth citrate for it to stabilize the phosphomolybdic acid complex formed during the interaction of inorganic phosphate and molybdate reduced by ascorbic acid. This method has also been adapted to microplates and has been used to determine the activities of Na/K ATPase and alkaline phosphatase of intestinal basolateral and luminal plasma membranes.

Alkaline Phosphatase↗
PubMed2002

Morphology of trachea in benign human tracheal stenosis: a clinicopathological study of 20 patients undergoing surgery.

Prolonged tracheal intubation of patients often leads to tracheal stenosis (TS), which may require surgical removal of the narrowed portion of the airway. We studied 20 patients with TS who underwent surgical ablation of the stenotic portion of trachea. The morphology of the tracheal segments was characterized and compared with clinical data and with the prognosis for the disease. We found that TS was usually due to an increase in the width of the mucosa as a result of the fibrosis associated with the chronic inflammation. Plasma cells were the predominant leukocyte type seen in the inflammatory infiltrates of the surgically removed portions of narrowed trachea. In the majority of TS samples, the epithelial surface was intact and presented cilia; in contrast, cilia disappeared when the tracheal lumen was completely obliterated. Mucosal cells and glands were also well preserved in TS samples. The need to remove TS segments was often related to previous tracheal surgery, which was also associated with closing of the tracheal lumen and ossification of cartilage rings. We conclude that (a). chronic inflammation and fibrosis are responsible for the narrowing of trachea in TS patients, (b). metaplastic ossification of cartilage rings only occurs after complete obliteration of the tracheal lumen, and (c). loss of cilia and presence of metaplastic bone tissue are indicators of a poor prognosis for TS.

Adult↗
PubMed2002

Heavy metals in soft tissues of Tursiops truncatus and Delphinus delphis from west Atlantic Ocean by X-ray spectrometry.

In this work, the concentration of heavy metals in muscle, liver, fat tissue and skin is studied in 15 Delphinus delphis and two Tursiops truncatus dolphins, stranded along the Portuguese coast of the Atlantic Ocean. Sample collection was performed post-mortem and the tissues were kept frozen until analysed. Sample preparation included lyophilising and grounding in a Teflon mill to avoid contamination by metals. The obtained powder was prepared as pellets for each sample and analysed directly by X-ray fluorescence spectrometry. The concentrations of K, Ca, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Hg and Pb were obtained. Significant differences between the muscle, the skin and the fat tissues were detected. Cobalt concentrations were similar in liver, skin and muscle. The levels of Ni, Rb and Sr are at the level of the detection limit and whenever measurable are rather constant in all the analysed tissues. The results show that the highest concentrations of Mn, Cu and Hg are always in liver tissues. Zinc and Se concentrations are higher in skin and Pb is present in very low concentrations in all the analysed tissues except in skin; Fe and As are enhanced in muscle and liver. In general, the two studied species did not seem to differ significantly in their heavy metals concentration in a given tissue.

Adipose Tissue↗
PubMed2001

Tracheal transplantation: cytological changes studied by scanning and transmission electron microscopy in the rabbit.

OBJECTIVES: Our goal was to offer a comprehensive cytological study of the changes in the trachea after experimental transplantation of the organ. STUDY DESIGN: Autografting of four tracheal rings was done in rabbits and tracheal samples were observed by electron microscopy from 1 week to 6 months after the surgery was performed. METHODS: Transmission and scanning electron microscopy were used to investigate the fine structure of tracheal samples of rabbits submitted to autotransplantation, and quantitative methods were used to compare several cytological parameters of the different groups of animals. RESULTS: We found that tracheal autografting was associated with acute injury of ciliated cells expressed by loss of more than 90% of cilia density on the tracheal epithelium 1 week after the transplantation was performed. The loss of cilia was balanced by an increase in mucous cells present on the tracheal lumen. Recovery of ciliated cells was observed 1 month after the tracheal autografting was performed. In contrast, only mild cytological modifications were seen in the cartilage tissue of the autografted trachea during the first weeks of transplantation; the structural alterations of the cartilage progressed up to the third month after transplantation, resulting in a moderate tracheal stenosis. CONCLUSIONS: The data indicate that 1) autotransplantation of four tracheal rings is a viable surgical procedure; 2) tracheal grafting causes severe acute changes of the epithelium that are, however, reversible in nature; whereas 3) the initial mild alterations induced by the autografting in the cartilage may evolve into tracheal stenosis.

Animals↗
PubMed1998

[Prenatal diagnosis. II. Importance of ultrasonographic markers in prenatal diagnosis of chromosome abnormalities].

The Medical Genetic Unit of the University of Zulia (MGUUZ) has developed a Prenatal Diagnosis Program (PDP) since January-1993, in which Genetic Risk Factors are determined in couples who request prenatal genetic counseling. In this program, different prenatal diagnostic procedures are performed to detect congenital defects during intrauterine life. One of these procedures is the Fetal Sonogram (FS). FS is a non invasive technique which permits the prenatal diagnosis of many genetic dysmorphic syndromes. Through the search of abnormal specific characteristics in the fetus, chromosomopathies may be suspected. These findings are named "Echosonographic Markers of Chromosomal Abnormalities" (EMCA). During three years (January-1993 to December-1996), patients attended in the PDP included 321 pregnant women in which 312 FS were performed. Abnormal outcomes were 22 (17 with isolated congenital malformations and 5 with EMCA). Only one fetus with chromosome abnormality (46,XX21q-) could not be detected by FS. The goals of this paper are: 1) to report 5 patients with sonographic markers suggestive of chromosomal abnormalities and 2) to show the FS usefulness in prenatal diagnosis of chromosompathies. We conclude that, in the search of the EMCA the FS should be offered systematically to all pregnant women without recognizable genetic risk. They are the main group with optimal reproductive age and in consequence, with the possibility of having a relatively major number of conception outcomes with congenital defects, with or without chromosomic etiology. The majority of those defects can be detected by FS and could allow us to select the patients in which the use of an invasive prenatal diagnostic procedure could be justified.

Adolescent↗
PubMed1997

In vivo monitoring of bone-Pb and retrospective exposure: an assessment in occupationally exposed subjects.

In this work we present the preliminary results of an investigation in to the bone burden of lead in occupationally exposed subjects. The assessment of bone lead levels normalised to the mineral content (mg/kg bone mineral) were carried out by means of an in vivo X ray fluorescence techniques (Pb-XRF). The measurements were performed on the second phalanx of the right index finger and the minimum detectable limits of the XRF techniques was estimated around 25-30 mg/kg. Although the blood lead level monitoring over long time seems to indicate working activities in environments with low sources of lead contamination, high Pb-XRF levels, and not well correlated with the exposure time, were found. These anomalous values could be explained in term of the dependence of zinc protoporphyrin assessment against the measurement time.

Bone and Bones↗
PubMed1997

[A proposal for worker's health surveillance with a gender perspective]

This paper deals with differences and inequalities. The current workers' health surveillance model is discussed, pointing to the need for a gender perspective in this area. The article maintains that certain classical notions should be reviewed and that risk maps can be more useful if they are capable of identifying exposure according to gender, thus enhancing the different kinds of division of labor under which they operate. Women workers' proposals are placed alongside sociological analyses in terms of the interface between production and reproduction and the debate over the gender perspective in the health-disease process. The paper concludes with an attempt to establish a new approach to workers' health surveillance, highlighting the centralness of work and the inter-subjectiveness of determining the relationship between production and health.

Journal Article↗
PubMed1997

[Comparison of extra renal potassium management in hypertensive, diabetic and normal subjects].

BACKGROUND: Sodium and potassium ions are involved in the regulation of blood pressure and the genesis of hypertension. AIM: To assess internal potassium balance, as a measure of sodium pump activity, in subjects with essential hypertension and diabetic patients. PATIENTS AND METHODS: Eleven hypertensive subjects, 5 non-insulin-dependent diabetics and 16 age matched controls were studied. An acute oral load of 0.8 mEq/Kg body weight of KCl was administered and blood samples were drawn every 30 min thereafter, until 120 min, to measure plasma K+ levels. Urinary K+ excretion during this period was also measured. In eight hypertensive patients, the test was repeated after two week of supplementation with 60 mEq/day of KCl. The maximal increase in plasma potassium levels and the time required to achieve the maximum concentration was recorded. RESULTS: All patients had normal serum creatinine levels. Mean fasting blood glucose of diabetic patients was 133 +/- 15.1 mg/dl. No difference between patients and controls in maximal increase plasma potassium increase, was observed. In hypertensive patients the lapse to achieve the maximal potassium concentration was longer than in controls. After the period of potassium supplementation in hypertensive patients, there was a significant increase in basal plasma K+ levels and the temporal pattern of plasma potassium increase was similar to that of controls. Between 63 and 68% of retained K+ load was translocated to the intracellular space at 120 min in all study groups. CONCLUSIONS: Internal potassium balance is not significantly altered in subjects with essential hypertension or in non-insulin-dependent diabetics.

Adult↗
PubMed1994

Autoantibodies to human nuclear lamin B2 protein. Epitope specificity in different autoimmune diseases.

The nuclear lamina of mammalian cells consists of three major proteins, lamins A, C, and B, and a fourth minor protein, lamin B2. Lamins belong to the family of intermediate filaments and are highly similar both in structure and primary sequence. They are organized in three well-defined domains: 1) a central alpha-helical rod, which is a secondary structure shared by all types of intermediate filaments, formed by three alpha-helices (coils 1A, 1B, and 2) and surrounded by 2) an amino-terminal head and 3) a carboxyl-terminal tail. Autoantibodies toward major lamin have been described previously in sera from patients with different autoimmune diseases. We chose an epitope mapping approach to further characterize the autoimmune response to nuclear lamin. Different lamin B2 domains were expressed as fusion proteins with the glutathione S-transferase and then used in immunoblotting experiments to analyze sera from patients with autoimmune diseases (chronic active hepatitis, SLE, rheumatoid arthritis, and polymyalgia rheumatica) and from healthy subjects. At a 1:1000 dilution, none of the control sera recognized any of the recombinant polypeptides. Conversely, reactive sera were present in all groups of patients. The ability to recognize a protein domain seemed to differ with the pathology. Most chronic active hepatitis sera were reactive to two or more lamin domains and reacting SLE sera always gave positive signals to coil 2 and/or coil 1B. Coil 2 was preferentially recognized by rheumatoid arthritis sera. Polymyalgia rheumatica sera differed from all of the others because of their low reactivity to the rod domain and preference for the C terminus, a lamin-specific domain.

Autoantibodies↗
PubMed1993

[Tomodensitometry and radioisotopic methods in the study of unilateral lung hyperlucencies of vascular origin].

Among the causes of the radiological entity known as unilateral or total hyperlucent lung is the decreased blood flow in the lungs. Unilateral and total hyperlucent lung results, among other factors, from the decreased intrapulmonary blood flow. Classically, the diagnosis and haemodynamic evaluation of these situations were usually made through invasive methods: right heart catheterism to perform angiopneumography and pressure evaluations as well as oximetry at several levels of the vascular network, thoracic aortography eventually associated with selective arteriography to detect the abnormalities of the systemic thoracic circulation. In this context, the authors propose for the diagnosis and study of this pathology, a new non-invasive methodology. In order to achieve this propose, we studied 8 patients, all of them performed clinical and laboratory evaluations, chest chi-ray, electrocardiographic and functional respiratory exams, as well angiopneumography, thoracic aortography tomodensitometry including qualitative (to study the lung arterial vasculature) and quantitative (to evaluate CT density of each lung in Hounsefield unit and two radioisotopic tests, including a ventilation/perfusion study with 133 chi e and HAM-99mTc, through an original software--four parameter histograms allowing simultaneous information of ventilation and perfusion at the pixel level and estimation of the V/Q; the other is the pulmonary gating through which it is possible to identify and quantify the arterio-arterial shunts.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1990

Infectious endocarditis in children.

With the object of analyzing current characteristics of infectious endocarditis (IE) in children, we carried out a retrospective study of 23 cases of IE in children under 15 years of age seen at the Hospital Ramón y Cajal in Madrid (Spain) between 1977 and 1985. The incidence was high (1.3 cases per 1000 children admitted). The male/female ratio was 2:1. Eight patients were under 2 years of age and 15 over 2 years, the majority being adolescents. The two groups presented marked etiological and prognostic differences. Congenital heart disease was the predisposing factor in 20 of the 23 cases. Streptococcus viridans (nine cases) and Staphylococcus aureus (eight cases) were the most frequent organisms. Fourteen cases were on a native valve and nine were secondary (seven of these on prosthetic patches). In spite of advances in therapy, IE continues to be a severe illness: the mortality rate in our series was 26%. Factors associated with a poor prognosis were: age less than 2 years, Staphylococcus aureus as the causative agent, and the presence of prosthetic material.

Adolescent↗
PubMed1990

Purification of a thermostable DNA polymerase from Thermus thermophilus HB8, useful in the polymerase chain reaction.

A thermostable DNA polymerase, isolated from the thermophilic strain Thermus thermophilus HB 8 was purified by a five-step procedure which provides a high yield and a homogeneous preparation. The molecular weight was estimated to be 67,000 daltons and the extension rate was determined to be 1500 nucleotides per minute. The enzyme works in polymerase chain reaction conditions similar to those used for Taq polymerase from Thermus aquaticus.

Base Sequence↗
PubMed1989

The effect of ischemic time and temperature on lung preservation in a simple ex vivo rabbit model used for functional assessment.

Despite 25 years of research in lung transplantation, little progress has been made in methods for improving lung preservation. To evaluate many factors that may affect lung function after preservation, we have developed a simple, reliable, and inexpensive animal model. This consists of an isolated rabbit lung preparation perfused with blood and ventilated with a closed-circuit system. Heart-lung blocks were harvested and the left lung was assessed after ligation of the right pulmonary artery and right main-stem bronchus. On completion of a storage period, the left lung was ventilated and perfused with fresh rabbit venous blood at a rate of 40 ml/min for 10 minutes. Assessment of lung function included gas analysis of infused and effluent blood, oxygen uptake, mean pulmonary artery perfusion pressure, and mean airway pressure. A control group and six preservation groups were evaluated, each with different storage temperatures (38 degrees C, 34 degrees C, 23 degrees C, 15 degrees C, 10 degrees C, and 4 degrees C). For each temperature, ischemic periods ranging from 1 to 30 hours were studied. In the control group, the lungs were assessed immediately after being harvested. In the preservation groups, the lungs were kept partially inflated, stored at a predetermined temperature by immersion, and later assessed after variable ischemic periods. Our studies demonstrated the following: (1) The degree of impaired lung function produced by ischemia is reflected by a decrease in oxygen uptake and in oxygen tension of the effluent pulmonary venous blood and an increase in pulmonary artery perfusion pressure; (2) hypothermia improves ischemic tolerance; (3) preservation of lung at 10 degrees C is superior to preservation at 15 degrees C and 4 degrees C. This screening model has allowed evaluation of independent multiple factors and methods pertinent to lung preservation and enables one to assess lung function reliably and rapidly.

Animals↗