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Biomedical subjects

A Szadowska

Publications and source records attributed to A Szadowska.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

The responsiveness of D1- and D2-dopamine receptors in the striatum and hypothalamus of spontaneous and vasopressin hypertensive rats.

Low doses of apomorphine (20-50 micrograms/kg) induced an increase in the activity of an endogenous inhibitor of cAMP dependent protein Kinases (type I inhibitor) in the striatum, anterior and posterior hypothalamus of normotensive rats by stimulating D2-dopamine receptors. In contrast, high doses of the compound (2-10 mg/kg) produced a dose dependent decrease in type I inhibitor activity. In the posterior hypothalamus of vasopressin hypertensive rats and SHR the maximal increase of type I inhibitor activity was markedly higher than in normotensive animals. Moreover, apomorphine induced the increase of type I inhibitor activity in a much wider range of doses. Only as high dose of the compound as 10 mg/kg was able to decrease type I inhibitor activity. This points to a marked supersensitivity of D2 receptors and suggests the subsensitivity of D1 receptors in this brain area of hypertensive rats. In contrast, in the striatum and anterior hypothalamus of hypertensive rats the apomorphine dose response curves were similar to those in normotensive rats. Thus, it seems tha hypertension is associated with the alteration in sensitivity of D2 and D1 receptors in the posterior hypothalamus, the brain area involved in regulation of blood pressure.

Animals↗
PubMedDate not supplied

The sensitivity of alpha-adrenoceptors in nucleus tractus solitarii, anterior hypothalamus and hippocampus of spontaneous and renal hypertensive rats.

The responsiveness of the endogenous type II inhibitor of protein kinases to clonidine was used as an index of the reactivity of alpha 2-adrenoceptors in the brain. The stimulation of postsynaptic alpha 2-adrenoceptors by clonidine resulted in a dose-dependent decrease in type II inhibitor activity. In the nucleus tractus solitarii and anterior hypothalamus of spontaneously hypertensive rats (SHR) and renal hypertensive rats (RHR) the clonidine-induced decrease in type II inhibitor activity was markedly reduced. In contrast, clonidine was equipotent in reducing type II inhibitor activity in the hippocampus of those rats and in control normotensive animals. In addition to that, in SHR and RHR the hypothermic activity of clonidine was not reduced. Thus, it seems that in experimental hypertension the decrease of the reactivity of alpha 2-adrenoceptors occurs in the brain structures responsible for the blood pressure regulation.

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PubMedDate not supplied

The responsiveness of central benzodiazepine and GABA(A) receptors in vasopressin and spontaneously hypertensive rats.

Administration of diazepam, an agonist of benzodiazepine receptors, and muscimol, an agonist of GABA(A) receptors, resulted in an increase in cytosol GABA-modulin in hypothalamus and cerebellum. Low dose of muscimol, ineffective by itself, completely antagonized the isoniazid, bicuculline and picrotoxin-induced decrease in GABA-modulin activity. In contrast, low dose of diazepam was able to block only the action of isoniazid. That confirms different mechanism of action of muscimol and diazepam. The increase in cytosol GABA-modulin activity in the anterior and posterior hypothalamus of spontaneously hypertensive rats (SHR) and of vasopressin hypertensive rats required much higher doses of muscimol than in normotensive animals showing subsensitivity of GABA(A) receptors in these brain structures. In contrast, the sensitivities of GABA(A) receptors in the cerebellum and of benzodiazepine receptors in the hypothalamus and cerebellum were equal to hypertensive and normotensive rats.

Animals↗
PubMedDate not supplied

The responsiveness of alpha 2-adrenergic receptors in hypothalamus of vasopressin-hypertensive rats.

Administration of clonidine produced biphasic changes in the type II inhibitor activity (endogenous inhibitor of protein kinases which specifically regulates phosphorylation mediated by cGMP-dependent system). Small doses of clonidine (10-50 micrograms/kg) produced an increase while large doses (200-1000 micrograms/kg) induced a decrease in the type II inhibitor activity. The both actions of clonidine were greatly reduced in vasopressin hypertensive rats suggesting subsensitivity of alpha 2-adrenergic receptors. Subsensitivity of postsynaptic alpha 2-receptors was also observed in anterior hypothalamus in in vitro experiments. Incubation of anterior and posterior hypothalamic slices with clonidine resulted in concentration-dependent increase in cGMP content and a decrease in the type II inhibitor activity. The clonidine action in anterior hypothalamus of vasopressin-hypertensive rats was greatly reduced. In contrast, the clonidine action in posterior hypothalamus was the same in vasopressin-hypertensive as in the control rats.

Animals↗
PubMedDate not supplied

[Proportion of B- and T-lymphocytes in lymph nodes removed from patients with Hodgkin's disease].

The proportions of T and B lymphocytes were determined in lymph nodes removed from 30 patients with Hodgkin's disease and in 18 control lymph nodes. In all lymph nodes obtained from patients with Hodgkin's disease histological examination demonstrated presence of typical granulation tissue of type Ns, Mc, Ld (changes of Lp type were not found). In the control lymph nodes no neoplastic changes or inflammatory reactions were observed. For identification of T cells the rosette test E was used and for identification of B cells --- the EAC rosette test and tests for presence of Ig on their surface by the immunofluorescent method (L Ig+). It was found that the proportions of T and B cells in the lymph nodes obtained from patients with Hodgkin's disease were not different from those in control lymph nodes. The percent values of T and B cells were similar in all three histological types of changes in Hodgkin's disease. Early radiotherapy was not connected with a change in T and B cell proportions in the irradiated lymph nodes.

B-Lymphocytes↗
PubMedDate not supplied

Decisive role of intermediate filament typing of tumor cells in the differential diagnosis of difficult fine needle aspirates.

Thirty-six diagnostically difficult fine needle aspirates from enlarged lymph nodes and malignant soft tissue tumors, containing tumor cells with scanty or no obvious light microscopic features indicative of their differentiation, were assessed by a panel of six cytopathologists. Their diagnoses were recorded and then compared with the definitive diagnosis established by combining the cytologic findings with the results of intermediate filament typing of tumor cells in the smears using monoclonal antibodies specific for each filament type. The results show that use of these antibodies can markedly improve the accuracy of the cytologic diagnosis of tumor type as well as revise or prevent erroneous cytologic diagnoses in difficult cases. This pertains especially to the differential diagnoses of carcinoma versus malignant lymphoma, carcinoma versus malignant melanoma, carcinoma versus sarcoma and squamous carcinoma versus carcinoma of simple epithelia. Intermediate filament typing of tumor cells in aspirates as an objective histogenetic criterium makes the differential diagnosis of the difficult aspirates much more reliable and reproducible, provided that appropriate questions are asked, monoclonal antibodies with well-defined specificities are used and the antigenicity of the intermediate filaments in smears is preserved.

Adult↗
PubMedDate not supplied

Synthesis of asymmetric 1,4-disubstituted piperazines and their psychotropic and cardiovascular actions. Part II.

New asymmetric piperazines 9-19 were obtained by condensation of 1-acyl-piperazines with 1,2-epoxy-3-chloropropane, arylacid chlorides, phenols, amines and 1-(alpha-naphthyloxy)-2,3-epoxypropane. Most of the compounds produced a transient hypotension and exerted a spasmolytic action of the isolated intestine. Compounds 10, 11 and 13 displayed a weak antiarrhythmic effect in the adrenaline arrhythmia test in rats. Compounds 14 and 15 increased the coronary flow, but their action was weaker than that of compound 4, described in the first part of the paper.

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