Biomedical subjects

N Nicolau

Publications and source records attributed to N Nicolau.

24 records · Page 2Linked to original sources

PubMedDate not supplied

Histoenzymological and ultrastructural studies of the macrophage-type pulmonary cell modifications under different chronic stasis conditions.

The optical histoenzymological and electronomicroscopical investigations were carried out en 90 pulmonary biopsies taken from patients under different chronic stasis conditions. To investigate macrophage-type cells we studied the reactions of acid phosphatase and non-specific esterase like enzyme markers, indicating the metabolic state activation degree of this cellular compartment. The ultrastructural examinations revealed the existence of two types of activated pulmonary macrophages. The former is the alveolar macrophage with a prevailing phagolysosome apparatus that pleads for phagocytic function and the latter is the interstitial macrophage with subcellular aspect corresponding to the synthesis and secretion function. The presence of these activated alveolar and interstitial macrophages, as well as their extremely increased number, plead for their direct participation in the appearance and aggravation of the morphophysiopathological disorders in the chronic stasis lungs.

Enzyme Activation↗

PubMedDate not supplied

Histoenzymological and ultrastructural investigations regarding the role of the endogenous peroxidase at the pulmonary level in cardiogenic pulmonary hypertension.

We found optically and ultrastructurally endogenous peroxidase in 90 intraoperatory pulmonary biopsies taken from patients with valvular cardiopathies and different degrees of pulmonary hypertension. The enzymatic activity increases proportionally to the pulmonary hypertension and it reaches its maximum in severe cases of hemosiderosis. Ultrastructurally we found two reaction types namely: 1) in peroxisomes of circulating monocytes turning into tissue ones, in medium or slight pulmonary hypertension (PHT) and 2) (as granular reactions on the nuclear membrane and endoplasmic reticle in alveolar macrophages, granular pneumocytes in aggravating and severe medium PHT. The presence of both these two types of reaction in the same cell demonstrates the passing stages from circulating macrophages to tissue ones attesting a transitional process of the phagocytic cells.

Heart Valve Diseases↗

PubMedDate not supplied

Histoenzymological and ultrastructural research of myocardial mitochondria in cardiac insufficiencies.

We performed histoenzymological and electron-microscopic investigations of 40 myocardial biopsies taken during open heart surgery under extracorporeal circulation (ECC) from patients with valvular cardiopathies and septal interatrial defects with various degrees of congestive cardiac insufficiency (CCI). The changes occurring in the topochemistry and intensity of the enzymatic reactions used as markers for mitochondria, namely SDH and LDH, demonstrated the existence of a correlation between the decrease of reactions of the CCI degree. The ultrastructural aspects of the mitochondrial changes attested the precocity and severity of damage in these organelles even from initial moments of hypoxia.

Cardiac Output, Low↗

PubMedDate not supplied

Electronmicroscopic and histoenzymologic study regarding morphophysiopathologic visceral modifications during open heart operations under extracorporeal circulation.

Morphophysiopathologic modifications occurred in myocardium, liver and lung during open heart operations under extracorporeal circulation had been studied using histologic, histoenzymologic, ultrastructural and biochemical investigations. Preexisting myocardic and hepatic lesions subsequent to chronic stasis and hypoxia are accentuated due to the "controlled shock" state induced by extracorporeal circulation. Mitochondrial marker enzymes like SDH, LDH and ATP-ase in the membrane are decreasing their levels and hydrolytic enzymes like acid phosphatase, nonspecific esterase (ANAE) and peroxidase are increasing their activity. These disseminated lesions can become irreversible under the conditions of a severe cardial insufficiency and of a prolonged operation. In the lung, the increase in the hydrolytic enzyme activity suggests the processes of phagocytosis and metabolization of red cells by macrophages.

Adenosine Triphosphatases↗

PubMedDate not supplied

Morphophysiopathologic studies on the biology of myocardium in acquired valvulopathies.

Myocardial lesions due to various valvulopathies were sampled during open heart surgery under extracorporeal circulation, and histologically, histoenzymologically and ultrastructurally investigated. Various cardiomyocitary and interstitial nonspecific progressive lesions, due especially to hemodynamic and hypoxic alterations, were identified. During the pathogenic stages, we remarked the onset and chronic evolution of perivascular and interstitial oedema, enhanced by a reduced lymph draining. The progressive processes of hyalinization, sclerosis and interstitial fibrosis were subsequent to the interstitial matrix modification. These processes accentuate the myocardial hypoxic lesion due to the nutritional and gaseous exchange alterations. The infrastructure, mitochondrial enzyme equipment, sarcoplasma and tubular network lesions, as well as the intramyocitary oedema that destroys the sarcomeric structure, ended with the activation of lysosome and lysosomal enzymes, giving rise to consequent cytolytic foci. Therefore, the process was extending. In this context, we remarked at the electronmicroscopic examination ventricular natriuremic granules, that are rarely mentioned in literature.

Adult↗

PubMedDate not supplied

Electronmicroscopic observations regarding the presence of natriuretic granules in the ventricle of patients with cardiopathies.

As part of studies regarding the human myocardium biology in hereditary and acquired cardiopathies, we showed the presence of natriuretic granules (NG) not only in atriums but also in ventricles, in ten of our cases with intraoperative myocardium biopsies. Ultrastructurally, the natriuretic granules occur in lesions produced by hemodynamic and consecutively hypoxic disturbances, being present at the ventricular level, too, both near the Golgi apparatus that secrets them, and diffusely, in cardiomyocytes, beneath the altered organelles and phagolysosomes. Their aspect in similar in cardiac malformations (DSIA. Fallot tetralogy) and in mitral valvulopathies, their abundance being in connection with congestive heart failure (CHF). Although predominant in CHF class I and II, they occur also in the severe decompensations class III and IV, being perhaps felt at the cardiac level as they are released in the blood. This phenomenon is expressed by electronmicroscopic presence of natriuretic granules in the subsarcolema and the increased plasma level of natriuretic peptide, according to biochemical findings reported in the literature. They produce a vasodilating, diuretic, natriuretic effect, contributing to blood pressure regulation and testifying in the neuroendocrine role of human myocardium.

Atrial Natriuretic Factor↗