Age-related structural and functional characteristics of cardiac myoendocrine cells of rats in a normal state and with hereditary hypertension

A qualitative and quantitative ultrastructural study of right atrial cardiomyocytes in WAG (normotensive control) and ISIAH (inherited stress-induced arterial hypertension) rats of different age (on day 18 of embryogenesis, on days 12 and 21 after birth, and at an age of 6 and 13 months) was performed. It was shown that, in embryos with an as yet incomplete atrial morphogenesis, secretory granules containing natriuretic peptides are actively formed, accumulated, and dissolved. In postnatal ontogeny, the secretory product is accumulated in atrial cells. In all ontogeny stages studied, the numerical density of secretory granules in the myoendocrine cells of hypertensive rats is greater and the qualitative composition of these granules is more diverse than in the control. It was established that, in atrial myocytes of ISIAH rats, the morphological signs of natriuretic peptide hypersecretion precede the development of genetically programmed high blood pressure. In adult hypertensive rats, hypertrophic and degenerative changes in myocytes are accompanied by excessive accumulation of secretory granules, some of which undergo intracellular degradation.     

Age-related characteristics of the organic angioarchitectonics of normal rats and in arterial hypertension

Architectonics of intraorganic arterial vessels in the cervical cortex, heart, kidneys and spleen have been investigated in 40 normotensive and spontaneously hypertensive rats, 6 months and 1 year old. In all the organs studied a direct dependence has been revealed between the degree of changes in the intraorganic arteries and relative content of the arterial vessels in the tissue organs. Functional changes of the arterial vessels in the organs studied observed during the hypertensive phase, transfer into the organic ones, as a result of prolonged adaptation, when the stage of a stable hypertension takes place.     

Age-related characteristics of intraorganic vascular structures of the cerebral cortex, heart, kidneys and spleen in rats in the normal state and in arterial hypertension

The work has been performed on 40 normotensive and spontaneously hypertensive rats at the age of 6 months-1 year. In all the organs studied a direct dependence between the degree of changes in the intraorganic arterial walls and a relative content of the arterial vessels in the organ tissues has been revealed. The functional changes of the arterial bed of the organs mentioned in spontaneously hypertensive rats during hypertensive phase at the stage of stable hypertension, as a result of a prolonged adaptation transform into organic ones.     

Bactericidal activity of phagocytes

In this review the recent data about oxygen-depended mechanism of host defense fulfilled by phagocytic cells were presented. The directions of the reactive metabolites oxygen formation and enzymic systems participating in its generation were described in details. The bactericidal characteristics of oxygen reactive metabolites are given, it was marked their role as like as physiologic messengers of inflammation. The differences in realization of the bactericidal activity of neutrophils or macrophages were characterized. The information about role of neutrophils in phagocytes cooperation in infection was analyzed as well as the proof of these cells ability to the synthesis and excretion of bioactive extracellularly substances with low-molecular weight     

Age-related characteristics of the electrical activity of the cardiac fibers in the human embryo

Transmembrane action potential and intercellular electric coupling have been studied in isolated heart during various stages of intrauterine growth of human embryos as well as in heart preparations of human adults. Formation of electrical properties of ventricular myocardium was slower than that of atrial fibres and was found to be fully completed in the first 14 weeks of intrauterine growth. Intercellular electrical coupling enhanced in the course of the embryonic development as indicated by a drop in the input resistance and an increase in electronic length.     

Endogenous peroxidase activity in mononuclear phagocytes

The diaminobenzidine (DAB) technique has been used to visualize the subcellular localization of peroxidatic enzymes in mononuclear phagocytes. The latter cells are part of the mononuclear phagocyte system (MPS), which includes the monocytes in the bone marrow and blood, their precursors in the bone marrow, and the resident macrophages in the tissues. The DAB cytochemistry has revealed distinct subcellular distribution patterns of peroxidase in the mononuclear phagocytes. Thus the technique facilitates the identification of the various phagocyte types: Promonocytes contain peroxidase reaction in the nuclear envelope, endoplasmic reticulum, Golgi apparatus, and cytoplasmic granules. Monocytes exhibit the reaction product only in cytoplasmic granules. Most resident macrophages show the activity only in the nuclear envelope and endoplasmic reticulum. Furthermore, new phagocyte types have been detected based on the peroxidase cytochemistry. Intermediate cells between monocytes and resident macrophages contain reaction product in the nuclear envelope, endoplasmic reticulum and cytoplasmic granules. The resident macrophages can be divided into two subtypes. Most of them exhibit the pattern noted above. Some, however, are totally devoid of peroxidase reaction. Most studies on peroxidase cytochemistry of monocytes and macrophages agree that the peroxidase patterns reflect differentiation or maturation stages of one cell line. Some authors, however, still interpret the patterns as invariable characteristics of separate cell lines. As to the function of the peroxidase in phagocytes, the cytochemical findings imply that two different peroxidatic enzymes exist in the latter cells: one peroxidase is synthesized in the endoplasmic reticulum of promonocytes and transported to granules via the Golgi apparatus. The synthesis ceases when the promonocyte matures to the monocyte. Upon phagocytosis the peroxidase is discharged into the phagosomes. Biochemical and functional studies have indicated that this peroxidase (myeloperoxidase) is part of a microbicidal system operating in host defence mechanisms. The other enzyme with peroxidatic activity is confined to the nuclear envelope and endoplasmic reticulum of resident macrophages in-situ and of monocytes at early stages in culture. As suggested by the subcellular distribution, the inhibition by peroxidase blockers, and the localization during phagocytosis studies, the latter peroxidase is functionally different from the myeloperoxidase.(ABSTRACT TRUNCATED AT 400 WORDS)     

Metabolic activity of phagocytes in experimental sporotrichosis

Phagocytosis plays an important role as a protective mechanism against infections, since polymorphonuclear leukocytes (PMN) and macrophages are the first cellular lines opposed to agressive microorganisms. In patients with sporotrichosis a diminished capability of killing engulfed yeast by their PMN has been described, but the origin of this deficiency remains unknown.In this work, partial aspects of the oxidative metabolism of PMN leukocytes and peritoneal macrophages of mongolian gerbils experimentally infected with sporotrichosis were studied. For this purpose the nitroblue tetrazolium (NBT) test as described by Baehner and Nathan (1) and myeloperoxidase activity measured according to Kaplow's method were utilized.The PMN and macrophages of mongolian gerbils infected with sporotrichosis showed increased reduction of NBT when compared with the phagocytic cells of normal ones, as is usually observed in most infections. Myeloperoxidase activity was diminished in both PMN and macrophages, but this diminution was statistically significant only in PMN leukocytes. These results show that part of the oxidative mechanisms of phagocytic cells can be impaired in experimental sporotrichosis, and could be correlated with the diminished fungicidal activity of PMN leukocytes obtained from patients infected with sporotrichosis.     

Assessment of the activity of tumor necrosis factor in normal state and in ovarian tumors

The cytotoxic activity of tumor necrosis factor of healthy individuals and patients with cystadenoma and adenocarcinoma of ovaries was investigated. Tumor necrosis factor (TNF) spontaneous activities of healthy donors and patients with cystadenoma of ovaries was the same. The level of TNF spontaneous activity of patients with adenocarcinoma was increased. LPS-induced TNF cytotoxicity in patients with cystadenoma was decreased. Mononuclear cells of patients with adenocarcinoma did not respond to LPS stimulation by increased TNF production.     

Age-related growth of the spleen in normal and glucocorticoid treated rats

1. Age-related changes in the growth, nucleic acid content and protein turnover of the spleen have been studied in normal male rats. 2. A rapid and marked atrophy of the spleen, was found 24 hr after exposure to cortisone or dexamethasone; increased rates of protein breakdown being primarily responsible. 3. Nonetheless, the total amount of protein synthesized in the spleen (measured in vivo) was significantly decreased (30-50%) 24 hr after exposure to these steroids. 4. This compared with only a 15% decrease in whole body protein synthesis, indicating a more pronounced hormonal effect on the spleen than on most other body tissues.     

Age-related changes in the physiological state of budding yeast cells

Biochemical and physiological changes occurring during the relative ageing of budding yeast cells were studied. In contrast to scar-free daughter cells the scar-bearing mother cells display a longer G1 phase of the cell cycle, synthesize RNA more slowly, consume oxygen more rapidly, possess a higher saturation constant K_s, and their cell walls are less resistant to mechanical strain.     

Age-related characteristics of the human acromioclavicular joint

By birth in the acromioclavicular joint the acromial end of the clavicle is osseous, and the acromion of the scapula is cartilaginous. The most intensive formation of the relief and configuration of the articular surfaces of the joint occurs from 1 to 3 years of age. In mature persons the form of the articular surface of the acromial end of the clavicle is often oval and that of the acromion of the scapula--ellipsoid. In newborns the areas of the articular surfaces are nearly equal. The area of the articular surface of the acromial end of the clavicle is significantly more than that of the acromion of the scapula during the periods from 1 to 3, from 13 to 17 and from 21 to 30 years of age. The articular cleft is revealed in the roentgenograms by 17 years of age, when synostosis process of the acromion of the scapula is completed. The thickness of the articular cartilage at different poles of the articular surfaces from birth up to 70 years of age is not equal and therefore it is possible to judge about nonequivalent functional loading on different areas of the articular cartilage. The articular cartilage of the acromial end of the clavicle from birth to 16 years of age is hyaline, after 17 years of age, they acquire the structure of the fibrous cartilage. In the articular cartilage of the acromion of the scapula, this rearrangement is realized more slowly: its fibrous structure is revealed after 23-24 years of age. Involutional changes in the joint are revealed during the fourth decade.(ABSTRACT TRUNCATED AT 250 WORDS)