[Hypertension discovered during blood pressure mass screening (clinical characteristic)].
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Hypertension↗
Biomedical subjects
W Januszewicz
Publications and source records attributed to W Januszewicz.
Certain aspects of diagnosis and treatment of phaeochromocytoma.
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Adrenal Gland Neoplasms↗
Ultrastructural and biochemical studies in phaeochromocytoma.
The purpose of the work was evaluation of the ultrastructure of phaeochromocytoma and its relation to catecholamine pattern and clinical features. The investigation included 6 patients aged 9-60 years. The urinary excretion of catecholamines and their metabolites as well as their content in the tumour were estimated. Ultrastructure studies were done with the Jem 7 and Jem 100C electron microscopes. Moreover, comparative studies of tissue adrenaline and noradrenaline content were performed in each tumour. The results of the study have disclosed morphological differences of tumours which enabled 3 types of tumours to be distinguished according to their structure and hormonal activity. Moreover, a relationship between the ultrastructure of the tumour and the clinical pattern of hypertension was disclosed.
Adolescent↗
Metabolism of 3H-catecholamines in the brain of spontaneously hypersensitive rats (SHR) after running stress.
The influence of stress on the metabolism of adrenaline (A) and noradrenaline (NA) in the prosencephalon (PC) and rhombencephalon (RC) of SHR and normotensive Wistar rats (WR) was studied. After intraperitoneal injection of 3H-tyrosine, radioactivity of 3H-adrenaline (3H-A), 3H-noradrenaline (3H-NA), total 3H-3-methoxy-4-hydroxyphenylglycol (3H-MHPG), total 3H-3,4-dihydroxyphenylglycol (3H-DHPG) and 3H-vanillylmandelic acid (3H-VMA) was measured in PC and RC of SHR and WR, non-stressed or subjected to running stress. Stress induced a significant decrease of 3H-A level in PC and RC of 8-week-old SHR while no stress-related changes in 3H-NA level were found in either part of the brain of SHR. In RC, 3H-A level was lower in older than in younger non-stressed SHR and decreased further after stress. In all SHR, stress enhanced formation of total 3H-MHPG and/or 3H-DHPG in PC, while increased 3H-VMA level was found only in PC of 24-week-old and in RC of 8-week-old stressed SHR. The results suggest that the decrease of the level of 3H-A in the brain of SHR is involved in their reaction to stress and may depend on increased metabolism mainly to glycols but also to VMA. The lower 3H-NA and 3H-A levels in the prosencephalon of non-stressed young and older SHR, concomitant with unaltered or elevated formation of their metabolites, may suggest higher release of the transmitters involved in the pathogenesis of spontaneous hypertension.
Animals↗
Metabolism of 3H-catecholamines in the heart and adrenals of spontaneously hypertensive rats (SHR) after running stress.
The metabolism of 3H-catecholamines after i.p. injection of 3H-tyrosine was studied in the heart and adrenals of spontaneously hypertensive (SHR) and normotensive Wistar (NCR) rats at rest and following running stress. In the heart of 8-week-old NCR a sharp stress-induced increase of the levels of 3H-A and 3H-DA with an elevation of the levels of their metabolites was observed. In contrast, there was no stress-related change in the levels of 3H-NA, 3H-A and 3H-VMA in the hearts of young SHR, while the 3H-DA level, though increased after stress, remained still lower than in the age-matched NCR. In the phase of established hypertension (24 weeks) lower levels of 3H-NA and 3H-A in the heart already present at rest, as compared with NCR, remained lower after stress but the elevation of the level of their metabolites 3H-VMA and 3H-MA, was similar in both strains. In the adrenals of 8-week-old SHR the basal 3H-A level was already higher than in NCR. Stress provoked a marked decrease of adrenal 3H-A accompanied by increased formation of 3H-MA and an increase in the levels of 3H-NA and 3H-DA, more pronounced in SHR than NCR. In the phase of advanced hypertension a further elevation of 3H-A and 3H-MA and an increase of basal 3H-DA level in the adrenals were found at rest. The decreased levels of 3H-catecholamines in the heart of stressed young and non-stressed older SHR may indicate an increase in their rate of release and/or their impaired synthesis. An increased basal level of 3H-A in the adrenals of SHR concomitant with the development of hypertension, may reflect an increased synthesis and/or decreased release, as evidenced by the proportionally lower increase of its extraneuronal metabolite 3H-MA. The adrenal response to stress, more intense in SHR than in NCR, may be considered as due to enhanced release of 3H-A from the gland.
Adrenal Glands↗
Neuropeptide Y and alpha-adrenoceptor interactions in patients with essential hypertension.
Neuropeptide Y (NPY) is a vasoconstrictor sympathetic cotransmitter and a modulator of adrenergic function whose role in hypertension is yet unknown. We studied the co-release of NPY and noradrenaline (NA) in patients with essential hypertension (13 females, 11 males, age 42 +/- 13 years) by measuring plasma levels of NPY-immunoreactivity (-ir, radioimmunoassay) and NA (radioenzymatic method) following administration of clonidine (CL 300 micrograms, p.o.). At rest, only NPY-ir levels significantly correlated with diastolic blood pressure (DBP, r = 0.42, p < 0.05). Three hours after CL, there were a decrease in mean arterial pressure and plasma NA (by 31 +/- 14 mmHG, p < 0.05 and 92 +/- 10 pg/ml, p < 0.01) but no change in NPY-ir levels. Patients were subsequently subdivided into groups with high (> or = 90 mmHg) or normal DBP (< or = 89 mmHg) and with or without elevated plasma NA levels (above or below 414 pg/ml, a normotensive mean +1 standard deviation). In hypertensives, but not in those with normal DBP, plasma NPY-ir correlated not only with DBP but also with systolic and mean blood pressure (r = 0.53 and r = 0.60, respectively) at rest. Hypertensives with "high" NA had significantly lower resting plasma NPY-ir levels than those with "low" NA (7.1 +/- 3.6 vs 14.7 +/- 6.0 fmol/ml, p < 0.05). In the former group, CL evoked the greatest fall in plasma NA, and also decreased NPY-ir levels by 50% (p < 0.05). Thus, patients with essential hypertension were found to display differential patterns of changes in sympathetic cotransmitters to clonidine. NPY may contribute to the increased blood pressure in hypertensives and together with NA, mediate hypotensive action of clonidine but only in the hyperadrenergic subgroup of hypertensives.
Adult↗
Pathogenesis of essential hypertension--present views.
The paper reviews the main lines of research pertaining to modern understanding of pathogenesis of essential hypertension. Attention is focused on the role of sympathetic activity, including the neuropeptide Y, as well as on those of atrial natriuretic peptide, endothelins and nitric oxide. The concept of endothelial dysfunction is discussed as a possible factor contributing to the development of hypertension, but also as its sequel. Finally, hyperinsulinemia and insulin resistance are viewed within a scope of interrelated factors of possible pathogenetic significance in essential hypertension. Genetic studies are singled out as the most promising line of further research.
Atrial Natriuretic Factor↗