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Biomedical subjects

G Bianchi

Publications and source records attributed to G Bianchi.

At least 451 records · Page 25Linked to original sources
PubMed1983

Sodium and potassium concentrations of renal cortical cells two animal models of primary arterial hypertension.

Electron microprobe analysis was used to determine cellular concentrations of potassium and sodium in renal cortical cells of hypertensive rats of the Milan strain (MHS) and spontaneously hypertensive rats of the stroke prone strain (SHRSP) and their respective controls. Potassium concentrations in proximal and distal tubular cells were similar in both strains of hypertensive rats compared with their normotensive controls. In MHS rats proximal tubular cell sodium concentration was lower than in controls by 3.1 mmol/kg ww, whereas in both proximal and distal tubular cells of SHRSP sodium concentrations were higher than in controls by 5.3 and 4.3 mmol/kg ww, respectively. These results indicate that changes in the transport characteristics of the renal tubular epithelium are a feature of both models of hypertension.

Animals↗
PubMed1983

Antihypertensive ergolinepropionamides.

The synthesis and the antihypertensive activity in rats of a series of 6-methylergolin-8 beta-yl-propionic acid derivatives are reported. The prolactin lowering activity (nidation inhibition test) in rats and the acute toxicity in mice were also studied as a measure of the specificity and safety of the potential antihypertensive compounds. From the structure-activity considerations reported here it is clear how modifications at the C8 side chain can improve the selectivity of the antihypertensive effects, whilst introducing substituents in other positions of the ergoline skeleton afforded unfavourable results in this respect. Compound 5, namely 2(R,S)-cyano-3-(6-methylergolin-8 beta-yl)-propionamide, emerged as the most interesting antihypertensive derivative.

Animals↗
PubMed1983

Cardiovascular effects of a new antihypertensive agent in several species.

The effects on blood pressure and heart rate of a new ergoline derivative, 2(R,S)-Cyano-3-(6-methylergolin-8 beta-yl)-propionamide (355/1057), were evaluated in different models of experimental hypertension as well as in normotensive rats, dogs and cats. Its interference with sympathetic neurotransmission was also studied in anaesthetized cats and dogs and in pithed rats. Dose-related hypotensive effects were found after single oral, intraduodenal and intravenous administration. In all the studied experimental models 355/1057 showed a prompt onset of action and a prolonged effect on blood pressure at low doses without substantially modifying heart rate. Some comparative results obtained with other commercially available antihypertensive agents are also reported. One month daily oral administration in SH-rats produced an antihypertensive effect persisting trough the entire experiment with no signs of tachyphylaxis. In anaesthetized dogs 355/1057 inhibited sthe pressor response elicited by bilateral carotid occlusion and in anaesthetized cats it reduced the response of the nictitating membrane elicited by electrical stimulation of both the pre- and post-ganglionic fibers but not by norepinephrine bolus injection.

Anesthesia↗
PubMed1982

Quaternary narcotic antagonists' relative ability to prevent antinociception and gastrointestinal transit inhibition in morphine-treated rats as an index of peripheral selectivity.

Single doses of naloxone (0.025 to 0.5 mg/kg) or of one of four quaternary narcotic antagonists (i.e. nalorphine allobromide, nalorphine methobromide, naloxone methobromide or naltrexone methobromide, 1 to 60 mg/kg) were given s.c. to rats before morphine, 5 mg/kg i.v. In the absence of antagonists morphine reduced G.I. transit of a charcoal meal to about 15% of drug-free controls and consistently delayed nociceptive reactions (55 degrees C hot plate) in all animals. Doses of antagonists slightly reducing morphine antinociception (centrally effective = A) and restoring G.I. transit to about 50% of drug-free rats (peripherally effective = B) were estimated. The A:B ratio, indicating peripheral selectivity, was at least 8 for any of the quaternary antagonists given 10 min before morphine, but prolonging this interval may have resulted in a lower figure (i.e. less peripheral selectivity) because of reduced A and increased B. This was definitely so for naltrexone methobromide (A:B, greater than 60 at 10 min, about 1 at 80 min) and was not apparent for nalorphrine methobromide according to available data, which for nalorphrine allobromide and to a lesser extent for naloxone methobromide showed only an increase in B at intervals longer than 10 min. Both morphine-induced antinociception and inhibition of G.I. transit were reduced by naloxone at the lower doses tested and were fully prevented at the higher. These findings indicated that, unlike naloxone, the investigated quaternary narcotic antagonists are interesting prototype drugs for selective blockade of opiate receptors outside the CNS, although certain critical aspects, possibly biological N-dealkylation to the corresponding tertiary antagonists, condition peripheral selectivity.

Analgesia↗
PubMed1982

Influence of familial hypertension of the donor on the blood pressure and antihypertensive therapy of kidney graft recipients.

The possibility that some hereditary factors favoring the development of 'essential' hypertension in man may act through modification of kidney function was evaluated in a retrospective study of 36 renal transplant recipients followed for 1 year. The patients were divided into two groups of 18 subjects each, matched for age, sex, body surface area, familial hypertension, duration of hemodialysis before transplantation and original kidney disease. In the first group, at least one of the donor's parents was hypertensive and in the second group all the members of the donor's family were normotensive. Plasma creatinine, daily dose of prednisone, number of rejection episodes and blood pressure were almost the same in both groups, but the requirement for antihypertensive therapy was significantly greater in the first group during the first 4 months after transplantation (p less than 0.05). Therefore, it seems reasonable to consider that there is some influence of familial existence of hypertension on the renal pressure regulatory mechanisms.

Adolescent↗
PubMed1982

Active and inactive renin and kidney function in young subjects with different predisposition to develop essential hypertension.

Renal and cardiac function were measured in 65 offspring of hypertensive parents (OHP) and in 56 offspring of normotensive parents (ONP). In two additional groups of 24 OHP and 42 ONP plasma renin activity (PRA) and plasma active (PRAC), inactive (PRIC) and total (PRTC) concentration were measured. OHP had significantly higher renal plasma flow (p less than 0.01), glomerular filtration rate (p less than 0.02) and 24-hour urinary output than ONP, while PRA was lower (p less than 0.01). The measurements of the different forms of renin gave the following results: PRIC and PRTC were lower in OHP than in ONP, but the only statistically significant difference concerns PRIC (p less than 0.025). A possible interpretation of these findings is that a primary increased tubular ion and water reabsorption might be the cause of the kidney function pattern seen in OHP.

Catecholamines↗
PubMed1982

Choice between US and CT in the radiological approach to the renal masses.

The diagnostic reliability of ultrasound (US) and computed tomography (CT) has been analyzed in 114 patients with renal masses (RM) detected by urography and consequently submitted to both exams. A flowchart is suggested in order to avoid useless examinations; accordingly, the US examination is always justified in the study of RM as opposed to the CT examination (requested only in 50% of RM) and angiography (requested only in 35% of RM).

Angiography↗
PubMed1981

Preoperative arterial occlusion in renal tumors: 3 years experience.

The authors describe their experience in preoperative embolization of 42 renal neoplasms. In all cases but one Gelfoam has been used for arterial occlusion with just a few and transient complications. Good hemostatic effect and décollement have been obtained irrespective of the diameter and vascularization of the tumor. To avoid late décollement difficulties and reduce the duration of clinical sequels the authors prefer, at present, to resort to surgery within 24 hours of embolization.

Adult↗
PubMed1981

Relationship between altered Na+--K+ cotransport and Na+--Li+ countertransport in the erythrocytes of 'essential' hypertensive patients.

1. The maximal rate of activity of sodium extrusion by the sodium pump, Na+--K+ outward cotransport, passive permeability to sodium and potassium, Na+--Li+ countertransport, and passive permeability to lithium were measured in 45 essential hypertensive patients, 24 young normotensive subjects with at least one hypertensive parent and 24 normotensive subjects with both parents normotensive. 2. The maximal rate of activity of the sodium pump and the rate constants for passive permeability to sodium, potassium and lithium were similar in the three groups. 3. The mean value for Na+--K+ outward cotransport was significantly lower and that for Na+--Li+ countertransport significantly higher in the hypertensive patients than in the normotensive subjects without a family history of hypertension, but there was a great overlap between individual values. The offspring of hypertensive parents had intermediate values. 4. A highly significant positive correlation existed between Na+--K+ cotransport and Na+--Li+ countertransport both in the normotensive and in the hypertensive subjects, indicating that in the latter there were some with high Na+--Li+ countertransport and others with low Na+--K+ cotransport. 5. In nine hypertensive families studied, if an alteration of the transport system was detected in a hypertensive propositus, the same type of alteration was also found in his still normotensive offspring, thus indicating a familial tendency for the alteration to occur.

Adolescent↗
PubMed1981

Plasma concentrations of catecholamines in two strains of spontaneously hypertensive rats at different ages.

1. Blood pressure was measured and plasma levels of noradrenaline and adrenaline were determined radioenzymatically under basal conditions and after 10% blood volume reduction in blood drawn through catheters previously implanted in young and adult rats of two different genetically hypertensive strains: the Kyoto strain (SHR) and the Milan strain (MHS), and in their respective controls: Wistar--Kyoto strain (WKY) and Milan normotensive strain (MNS). 2. Under basal conditions no differences were observed between plasma noradrenaline and adrenaline levels in SHR and MHS rats and in the controls, at any age. Haemorrhage produced a greater fall in the blood pressure (P less than 0.01) of young and adult hypertensive strains (SHR-MHS) than in WKY and MNS rats, and a greater rise in plasma adrenaline (P less than 0.01). 3. These results suggest that: (a) there may be differences in involvement of the sympathetic nervous system in the pathogenesis of hypertension in SHR and MHS rats but not such as to cause differences in plasma catecholamine levels in either young or adult rats; (b) haemorrhage activates the sympatho--adrenal systems more in SHR and MHS rats, than in controls, and the greater percentage fall in blood pressure is probably due to a difference in reflex venoconstriction.

Aging↗