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Biomedical subjects

L Donato

Publications and source records attributed to L Donato.

At least 91 records · Page 5Linked to original sources
PubMed1987

Increased permeability of hamster microcirculation to glycosylated albumin.

The permeability of the microcirculation to native and glycosylated albumin was tested in 25 non-diabetic Syrian hamsters. The microvasculature of the cheek pouch was studied by a fluorescent video-microscopy technique after the animals had been injected with fluorescent native or glycosylated albumin or with both. Native albumin remained in the cheek pouch microvasculature, whereas glycosylated albumin leaked out of the microvascular bed along the postcapillary and collecting venules. The extravascular leakage of glycosylated albumin, probably due to its electrical or conformational change, may represent the initial event in the development of diabetic microangiopathy.

Animals↗
PubMed1987

Renal scintigraphic captopril test in the diagnosis of renovascular hypertension.

Angiotensin converting enzyme (ACE) inhibitor-induced renal failure has been reported in bilateral renal artery stenosis and in stenosis in solitary kidneys, but not in unilateral renal artery stenosis. In these patients, however, a functional impairment of the kidney ipsilateral to the stenosis can often be detected after ACE inhibition by scintigraphic techniques employing glomerular radionuclide tracers like 99mTc-diethylenetriamine pentaacetic acid (DTPA). Dynamic renal scintigraphy with 99mTc-DTPA before and 1 hour after administration of captopril, 25 mg (renal scintigraphic captopril test; RSCT), was performed in a selected series of 39 hypertensive subjects with suspected renovascular hypertension. Changes in glomerular filtration rate induced by captopril on the individual kidney were estimated by assessing the early (120-180 seconds) DTPA uptake by the kidney. Values were expressed as the ratio between the kidney with the lower uptake and the contralateral one in 34 patients and as the ratio of the kidney counts to the injected dose in five patients with solitary kidneys, aortic coarctation, or both. Compared with precaptopril values, postcaptopril uptake decreased markedly in 14 subjects (-62.42 +/- 30.94 [SD]%; range, -25 to -100%) and decreased modestly or even increased in the other 25 (+0.57 +/- 9.83%; range, +28 to -13%). Of the 14 subjects considered to be RSCT-positive diagnostic workup revealed either established (10) or strongly suspected (2) renal artery stenosis in 12 and aortic coarctation in 2 subjects. In another patient with established renovascular hypertension, results of the RSCT were negative when performed in the supine position but became positive when repeated in the sitting position.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Diagnosis of myocardial ischemia in man. Concluding remarks: the "stunned" cardiologist.

According to Sherrington, the integrative skill of the nervous system allows the organism to react to the environment 'as a whole' and not 'as a mere collection of organs'. Similarly, the cardiologist--both in research and in patient care--cannot consider the heart 'as a mere collection of techniques'. In general, any new techniques leads to better understanding of disease, and at the same time to better understanding of the value and limitations of the methods in use. The ability to integrate different technical information in sound clinical reasoning, the ability to talk, understand and convey confidence to the patient as a human, will further increase in importance with the growth of technology. The alternative is that cardiologists will disappear, to be replaced by a bunch of 'stunned' subspecialists.

Angina Pectoris↗
PubMed1985

Low-dose aspirin in patients recovering from myocardial infarction. Evidence for a selective inhibition of thromboxane-related platelet function.

The adequacy, selectivity and long-term persistence of inhibition in cyclooxygenase-dependent platelet function by a daily low-dose (0.45 mg kg-1 day-1) aspirin treatment have been evaluated in 15 patients after a recent (less than 17 days) acute myocardial infarction. Serum thromboxane (TX) B2, an index of platelet TXA2 production, was decreased by 94-98% (P less than 0.001) by aspirin, while urinary excretion of 6-keto-prostaglandin F1 alpha, as an index of extraplatelet cyclooxygenase activity, remained unchanged. Compared to placebo, aspirin induced a persistent increase in bleeding time (% difference 45.6 +/- 21.4, mean +/- SD) and a decrease in platelet aggregation by ADP, epinephrine, collagen and arachidonic acid. No tendency towards an attenuation of the effects was apparent for the period of aspirin administration (4 weeks). Aspirin 0.45 mg kg-1 day-1 is adequate and selective in the long-term inhibition of TX-related platelet function in patients after acute myocardial infarction. The clinical effectiveness of such a regimen remains to be proven in clinical trials.

Adult↗
PubMed1985

Acute effect of captopril on single kidney glomerular filtration rate in arterial hypertension.

Recent studies have reported that captopril can acutely induce a marked decrease of glomerular filtration rate in kidneys affected by renal artery stenosis, an effect detectable by scintigraphic techniques. Experience which confirms and extends this observation, obtained in five patients with renovascular hypertension, is reported here. For comparison, eight essential hypertensives and six patients with non-vascular unilateral renal diseases were studied. In each patient the ratio of glomerular filtration rate between the two kidneys was estimated during two consecutive scintigraphic studies with the glomerular tracer 99mTc-DTPA: in all renovascular patients captopril induced a marked decrease of glomerular filtration rate on the affected side, whereas negligible changes were observed in all other subjects. These results confirm that captopril may almost completely suppress glomerular filtration in kidneys affected by unilateral renal artery stenosis, an effect which may not be apparent clinically because of compensation by the other kidney, but which is scintigraphically detectable. Renal scintigraphy after captopril is easy to perform and non-invasive. It therefore seems to be a promising tool for the screening of renovascular hypertension.

Captopril↗
PubMed1981

Comparison of outward and inward Na+/K+ cotransport-mediated fluxes in erythrocytes of essential hypertensive patients. Preliminary results.

A hereditary defect in the outward ouabain-resistant, furosemide-sensitive (ORFS) Na+/K+ cotransport has recently been reported by Garay and Meyer in erythrocytes of essential hypertensive patients and some of their normotensive offsprings. Since Na+/K+ cotransport in erythrocytes operates bidirectionally, the same defect might be detectable in the ORFS component of K+ influx rate. To test this hypothesis outward and inward Na+/K+ cotransport measurements were performed in erythrocytes of hypertensives and normotensive controls. Our preliminary results confirm the observation of a reduced outward cotransport in essential hypertension and also suggest that inward cotransport may be reduced in essential hypertension.

Adult↗
PubMed1978

The kinetics of plasma noradrenaline in normal and hypertensive subjects.

1. The kinetics of plasma noradrenaline have been determined in normal and essential hypertensive patients by intravenous injection of tritiated noradrenaline and serial mixed venous sampling. 2. The metabolic clearance rate of plasma noradrenaline in normal subjects was approximately 1 1 min-1 m-2, whereas in essential hypertensive patients it was significantly reduced to approximately 0.6 1 min-1 m-2. 3. Metabolic clearance rate was negatively correlated to mean arterial blood pressure and total peripheral resistances. 4. Particularly low values of metabolic clearance rate were found in two patients with congestive heart failure and one with phaeochromocytoma. 5. We propose that the access of plasma noradrenaline to the main removal mechanisms takes place in competition with the flow of unlabelled endogenous noradrenaline directly released by nerve endings. The slower removal of plasma noradrenaline in essential hypertension could then express a larger release of endogenous noradrenaline in this condition.

Adrenal Gland Neoplasms↗
PubMed1978

Peripheral handling of angiotensin II and blood pressure control in hypertensive patients with unilateral and bilateral renal disease.

PRA, AII CR, AII E and cardiac output have been measured in 9 normals and in 22 hypertensives: 8 with URD, 12 with BRD and 2 with MHY. PRA, as well as AII E, shows the highest values in BRD and MHY patients. AII CR is directly correlated with blood pressure levels in URD and BRD patients (p less than 0.05 and p less than 0.001, respectively). A significant positive correlation is found between AII E and TPR (within each group of patients and among all subjects) and between PRA and TPR within the hypertensive patients. These data suggest that peripheral handling of AII is involved in the control of blood pressure in the patients studied.

Angiotensin II↗
PubMed1976

Angiotensin II metabolism and blood pressure in chronic renal disease.

A direct positive correlation has been found between mean blood pressure (MBP) and angiotensin II metabolic clearance rate (AII MCR) (p is less than 0.001) in 12 hypertensive patients with chronic renal disease (CRD) while it is not discernible in nine normals. A strong positive correlation appears between angiotensin II arterio-venous extraction (AII E) and total peripheral resistance in the two groups when analysed both jointly or separately (p is less than 0.001 in all instances). As MBP equals cardiac output (CO) x TPR and AII MCR equals CO x AII E percent, the only parameter which makes the two groups different in the relation MBP/AII MCR is the impairment of CO autoregulation in CRD cases. AII peripheral extraction and degradation is closely linked to the control of peripheral vascular resistance in the two groups.

Angiotensin II↗