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Biomedical subjects

A Nava

Publications and source records attributed to A Nava.

At least 181 records · Page 10Linked to original sources
PubMedDate not supplied

Evaluation of adenosine deaminase activity in the Mycobacterium tuberculosis culture supernatants.

BACKGROUND: Adenosine deaminase (ADA) catalyzes hydrolytic and irreversible deamination of deoxyadenosine into deoxyinosine and of adenosine into inosine, and is related to lymphocytic proliferation and differentiation. The measurement of ADA activity in body fluids is a useful tool in the evaluation of mycobacterial infections. Elevated ADA activity has been found in pleural effusions of patients with pleural tuberculosis relative to those from patients with nontuberculous pleural diseases, and is mainly associated with cellular host factors such as monocyte-macrophages or lymphocytes. In contrast, there is little information about ADA activity measurement in mycobacteria culture supernatants. METHODS: We evaluated ADA activity as described by Giusti in the culture supernatants of eight Mycobacterium tuberculosis isolates. RESULTS: Mycobacteria culture supernatants did not display any ADA activity. CONCLUSIONS: This result supports the notion that Mycobacterium tuberculosis is not the source of ADA activity. However, increased ADA activity in biological fluids from tuberculosis patients might be due to the interaction of the mycobacterium with host factors.

Adenosine Deaminase↗
PubMedDate not supplied

What is the Brugada syndrome?

In 1992, Brugada and Brugada reported a distinct subgroup of patients with episodes of "idiopathic"polymorphic ventricular tachycardia or ventricular fibrillation characterized by a unique electrocardiographic (ECG) pattern, which consisted of right bundle branch block and ST-segment elevation from V1 to V2-V3. As in patients with long QT syndrome, the ECG changes and the ventricular electrical instability could not be explained by structural heart disease, myocardial ischemia, or electrolyte disturbances. The syndrome can be inherited and predominantly affects males. Clinical presentation includes cardiac arrest or syncope caused by rapid ventricular tachycardia or fibrillation characteristically occurring at rest or during sleep. The clinical outcome of affected patients is poor unless they receive an implantable cardioverter defibrillator. The ECG pattern and the electrical ventricular instability have been explained by the dispersion of repolarization between the right ventricular epicardium and endocardium, which predisposes to local reexcitation of myocytes with different action potential durations. A disease-causing missense mutation in the cardiac sodium channel gene SCN5A has been recently reported in patients with Brugada syndrome. It is mandatory for the clinician to carefully rule out any organic heart disease before suggesting a diagnosis of Brugada syndrome, because the typical ECG pattern with the risk of sudden arrhythmic death is also observed in patients with structural heart diseases in the setting of arrhythmogenic right ventricular cardiomyopathy.

Adult↗
PubMedDate not supplied

Arrhythmogenic right ventricular cardiomyopathy: current diagnostic and management strategies.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heart muscle disease of unknown etiology characterized by the peculiar right ventricular (RV) involvement. Distinctive pathologic features are myocardial atrophy and fibro-fatty replacement of the RV free wall, and clinical presentation is usually related to ventricular tachycardias with a left bundle branch block pattern or ventricular fibrillation leading to cardiac arrest, mostly in young people and athletes. Later in the disease evolution, progression and extension of RV muscle disease and left ventricular involvement may result in right or biventricular heart failure. The diagnosis of ARVC may be difficult because of several problems with specificity of ECG abnormalities, different potential etiologies of ventricular arrhythmias with a left bundle branch morphology, assessment of RV structure and function, and interpretation of endomyocardial biopsy findings. Therefore, standardized diagnostic criteria have been proposed by the Study Group on ARVC of the European Society of Cardiology. According to these guidelines, the diagnosis of ARVC is based on the presence of major and minor criteria encompassing electrocardiographic, arrhythmic, morphofunctional, histopathologic, and genetic factors. Since the assessment of sudden death risk in patients with ARVC is still not well established, there are no precise guidelines to determine which patients need to be treated and what is the best management approach. The therapeutic options include beta-blockers, antiarrhythmic drugs, catheter ablation, and implantable cardioverter defibrillator (ICD). The ICD is the most effective safeguard against arrhythmic sudden death. However, its precise role in changing the natural history of ARVC by preventing sudden and nonsudden death needs to be evaluated by a prospective study of a large series of patients. In patients in whom ARVC has progressed to severe RV or biventricular systolic dysfunction with risk of thromboembolic complications, treatment consists of current therapy for heart failure including anticoagulant therapy. In cases of refractory congestive heart failure, patients may become candidates for heart transplantation.

Anti-Arrhythmia Agents↗
PubMedDate not supplied

Vascular endothelial growth factor and hypertrophic osteoarthropathy.

OBJECTIVE: Hypertrophic osteoarthropathy (HOA) is characterized by the coexistence of digital clubbing and periosteal proliferation of the tubular bones. Localized vascular proliferation associated with platelet/endothelial cell activation are recognized features of this syndrome. Current knowledge suggests that HOA develops from the presence in the systemic circulation of one or more growth factors that are normally inactivated in the lungs. The nature of these purported growth factors has not yet been identified. Vascular endothelial growth factor (VEGF) has several features that may fit in with the pathogenesis of HOA. The objective of our study was to measure serum and plasma levels of VEGF in different groups of patients with HOA. METHODS: We studied 24 patients with HOA; of these, in 12 the HOA was secondary to cyanotic congenital heart disease and in 7 to lung cancer, while 5 represented primary cases. As controls we studied 28 individuals without HOA; of these, 12 were apparently healthy individuals, 7 had cyanosis secondary to chronic obstructive pulmonary disease, and 9 had lung cancer. ELISA was used to measure serum and plasma levels of VEGF. RESULTS: Plasma levels of VEGF were significantly higher in the patients with primary HOA (median 46.2; range 19.4-398.8 pg/ml) and in those with lung cancer-HOA (median 75.5; range 24.6-166.7), compared to healthy controls (median 7.4; range: 0-26.1), p < 0.05. Serum VEGF levels were higher in patients with lung cancer and HOA (median 411.4; range 164.2-959.5 pg/ml) compared with lung cancer patients without HOA (median 74.5; range 13.2-205.4), p < 0.001. CONCLUSIONS: Patients with primary HOA and those with HOA and lung cancer have increased circulating levels of VEGF. This cytokine may play a role in the pathogenesis of HOA.

Adult↗
PubMedDate not supplied

IgG subclass reactivity to Trypanosoma cruzi in chronic chagasic patients.

BACKGROUND: The anti-Trypanosoma cruzi antibodies isotype profile in Chagas' disease has been studied in relation to different clinical manifestations. A high titer of IgG anti-T. cruzi antibodies is found in patients with cardiac involvement, while a high titer of IgA anti-T. cruzi antibodies is associated with digestive forms. OBJECTIVE: The aim of this work was to analyze the IgG subclass reactivity of anti-T. cruzi antibodies in patients with chronic Chagasic cardiomyopathy. METHODS: Twelve consecutive chagasic patients were analyzed for IgG subclass reactivity to a T. cruzi antigenic extract. They had a complete clinical evaluation, peripheral EKG, echocardiography, left ventriculogram, and coronariography. RESULTS: All patients came from rural areas of Mexico and had lived in endemic zones for over seven years. They presented left ventricular endsystolic dimension above 42 mm in 58% (7/12) and ejection fraction below 50% in 58% (7/12). We found that IgG1 and IgG2 anti-T. cruzi antibodies showed higher titer than IgG3 antibodies, with consistently low titer of IgG4 antibodies. Expression of the four IgG subclasses of anti-T. cruzi antibodies suggest a mixed Th1/Th2-like immune response under a probably continuous chronic antigenic stimulation. On the other hand, high levels of IgG2 anti-T. cruzi antibodies showed a tendency to be associated with severe cardiomegaly. CONCLUSIONS: Our results suggest that a mixed Th1/Th2-like immune response may take place in chronic chagasic patients under a chronic antigenic stimulation.

Adult↗
PubMedDate not supplied

[Validazione della versione italiana del Brief Pain Inventory nei pazienti con dolore cronico].

BACKGROUND: The purpose of this study has been the validation of an Italian version of the Brief Pain Inventory (BPI), Breve Questionario per la valutazione del Dolore (BQVD), in patients with chronic pain not-caused by neoplastic illness. METHODS: The analysis has been proposed to 113 patients affected by different kinds of chronic pain of non-neoplastic origin while hospitalized, both as outpatients or as in-patients. The descriptive analysis of the specimen and of each item of the BPI has been carried out. Moreover, the psychometric characteristics of the analysis, intended as an instrument to describe intensity of pain and its interference in the various aspects of life have been investigated, evaluating with factorial analysis its validity both as a construct, and its internal coherence calculating the Cronbach's alpha of the whole instrument and of each identifier with factorial analysis. RESULTS: From the factorial analysis emerged a frame with three factors that have been identified as Pain intensity, Pain interference in emotional sphere and Interference in working activities. CONCLUSIONS: The Brief Pain Inventory can be considered a suitable useful instrument in the global evaluation of patients affected by chronic pain since its allows a contemporaneous analysis of three factors that characterize the phenomenon and contribute equally in defining the various facet of the pain universe. The Italian version of the BPI may be included in the essential evaluation instruments in the diagnosis and therapy of chronic pain.

Adult↗
PubMedDate not supplied

[A comparison of the life habits of abstemious patients and drinkers].

The life habits of 358 males abstemious (ABS) and 248 male risky or with harmful alcohol consumption (BRD) are compared; selected from the patients attending to a clinic of familiar medicine, of the Instituto Mexicano del Seguro Social (IMSS) and to General Hospital of the Secretaria de Salubridad y Asistencia (SSA). BRD are different from ABS because of a sedentary life, tobacco consumption, higher frequency of other drug use, poor nutrition, over weighted and poor physical condition. The difference between ABS and BRD is not only due to the alcohol consumption and related problems, but two groups of individuals with different ways of life. The present paper shows the first Mexican results of an International Multicentric Investigation coordinated by World Health Organization (WHO).

Adult↗
PubMedDate not supplied

[Arrhythmogenic myocardiopathy of the left ventricle: dynamic ECG. Morphologic data and age of the patient in the prediction of the onset of arrhythmic events].

In 57 patients with arrhythmogenic right ventricular cardiomyopathy, 34 males 23 females, aged 5 to 60 average 27.93 years, arrhythmias recorded during the whole clinical history have been compared with the 24 hours ECG ambulatory monitoring data, age and anatomic extension of the disease. In 77.77% of patients with history of sustained ventricular tachycardia Holter monitoring showed Lown class less than or equal to 3 arrhythmias, in 75% of patients with ventricular fibrillation Holter monitoring showed no arrhythmias. 55.88% of patients whose Holter monitoring documented Lown class less than or equal to 3 arrhythmias had more severe arrhythmias in their history. There is not a close relation between Holter data and arrhythmias that occurred during the whole history; however, Holter monitoring is a useful tool in evaluating risk when it shows complex arrhythmias.

Adolescent↗
PubMedDate not supplied

[Superior axial deviation in the young adult. An electro-vectorcardiographic study].

We analyzed the VCGs of 100 young subjects without apparent cardiac disease showing an ECG superior Axis Deviation, i.e. AQRS greater than - 30 degrees, and a rS aspect in V1. Our findings demonstrated that, in these subjects, the superior axis deviation is due to a distal right bundle branch block with posterior displacement of the terminal forces in 78% of the cases. The other cases being left anterior hemiblocks, either isolated (12%) or associated with a block of the anterior subdivision of the right bundle branch (10%). The differential diagnosis, easy on VCG, is sometimes very difficult on ECG. The most reliable ECG criteria to discriminate this kind of right bundle branch block from left anterior hemiblock are: intrinsic deflection in a VL-V6 greater than or equal to 0.015" (sensitivity 100%; specificity 57%), RV6/Ra VL ratio greater than 1 (sensibility 100%; specificity 50%) and the presence of a notched R wave in L2, L3 and a VF (sensitivity 90%; specificity 100%).

Adolescent↗