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Biomedical subjects

G Grassi

Publications and source records attributed to G Grassi.

At least 307 records · Page 17Linked to original sources
PubMedDate not supplied

Structure-effect relationships of amiodarone analogues on the inhibition of thyroxine deiodination.

OBJECTIVES: Amiodarone (AMI) has proven to be a potent anti-arrhythmic compound. Due to the structural similarity between AMI and thyroid hormone, it is possible that the drug could inhibit the activity of the 5'-thyroxine-deiodinase. METHODS: AMI analogues resulting from (1) dealkylation, (2) deiodination and (3) deamination were synthesised and used as inhibitors in an in vitro biotransformation reaction of thyroxine (T4) to 3,3',5'-triiodothyronine (T3). Using high-performance liquid chromatography and ultraviolet detection for quantifying T3, it was found that the 5'-T4 deiodinase type I was involved in the reaction. On separate occasions, AMI or an AMI analogue was added to the reaction as an inhibitor. RESULTS: All studied AMI analogues inhibited 5'-T4 deiodination competitively (Ki value range 25-360 microM). In the concentration range of 1-1000 microM, AMI and its N-desethylated, deiodinated analogues inhibited 5'-T4 deiodination very weakly. AMI analogues with a hydroxyl group at the 4-position were strong inhibitors. Moreover, diiodo-AMI analogues inhibited 5'-T4 deiodination more strongly than their corresponding monoiodo- or deiodinated derivatives. CONCLUSION: It is likely that the degraded products of AMI could be responsible for thyroid dysfunction toxicosis in AMI therapy.

Amiodarone↗
PubMedDate not supplied

[Output standard in the mental health services of Reggio Emilia, Italy. Methodological issues].

OBJECTIVE: The project Output Standards of the Mental Health Department (MHD) of Reggio Emilia is set out to define outputs and quality standards and to guarantee transparency and to facilitate organizational improvement. METHODS: The MHD started an interprofessional working group that defined the MHD outputs as long as process, quality peculiarities, indicators and standards for each output. The MHD Director validated the group results. RESULTS: The MHD defined 9 outputs and its indicators and standards and consequently modified its data registration system, the way to supply free and partially charged services and budget indicators. As a result, a new instrument for management and quality control has been provided. CONCLUSIONS: The A. maintains that to define outputs, indicators and standards will allow to compare several services of the Department, get them omogeneous and guarantee and improve quality.

Catchment Area, Health↗
PubMedDate not supplied

Evaluation of a slow-release clonidine preparation by direct continuous blood pressure recording in essential hypertensive patients.

The antihypertensive effect of a slow-release (SR) clonidine preparation was evaluated in hypertensive patients not confined to bed using a 24-h intraarterial blood pressure monitoring (Oxford) method. The monitoring was carried out during placebo administration and after 7-10 days of daily administration of SR clonidine in a single oral dose (250 or 500 microgram). An analysis of all the blood pressure values obtained was performed by computer. The results were as follows: (a) SR clonidine significantly reduced the 24-h systolic and diastolic arterial pressure by 16 and 10 mm Hg, respectively (mean +/- SE). (b) The reduction was well evident throughout the 24-h period, the average decrease in mean arterial pressure observed during the first, second, and third 8-h period after the administration of the drug being 11, 14, and 14 mm Hg, respectively. (c) The blood pressure reduction was similar during the daytime and the nighttime, despite the lower base-line value that occurred in the latter condition. (d) There was no consistent change in blood pressure variability, as measured in each patient by the standard deviation of the blood pressure values, with SR clonidine. SR clonidine caused a reduction in heart rate that, as that in blood pressure, was well evident throughout the 24 h. It is concluded that SR clonidine is an effective antihypertensive agent and that a single administration of this drug can produce a clear-cut reduction in the blood pressure values of hypertensive patients for a 24-h period.

Adult↗
PubMedDate not supplied

Continuous vs intermittent blood pressure measurements in estimating 24-hour average blood pressure.

In the past few years noninvasive automatic blood pressure (BP) recorders have been increasingly used to estimate patients' 24-hour BP more accurately than by one or few isolated measurements. However, these recorders only allow BP to be intermittently measured at intervals between 5 to 30 minutes, which means that the number of values collected over 24 hours (10 to 100) remains a tiny fraction of the thousands of values that occur during the same period. To determine whether this represents a limitation to this approach, BP was recorded intraarterially for 24 hours (Oxford method) in 20 ambulant hypertensive patients. A beat-to-beat analysis of the BP recording was provided by a computer, and the average 24-hour systolic, diastolic, and mean BP values were compared with those obtained by analyzing single BP waves of the same recording at intervals of 5, 10, 15, 30, and 60 minutes. In each subject the average 24-hour BP values obtained by the beat-to-beat analysis closely corresponded to those obtained by the analysis performed at 5-, 10-, 15-, or 30-minute intervals. In most subjects, this was the case also when the analysis was performed at 60-minute intervals. These findings demonstrate that intermittency of measurements does not limit the accurate assessment of true average BP. Indeed, accurate assessment can be achieved at intervals as much as 30 or 60 minutes apart.

Adult↗
PubMedDate not supplied

Twenty-four-hour hemodynamic profile during treatment of essential hypertension by once-a-day nadolol.

The effect of nadolol (N) on 24-hour blood pressure (BP) and heart rate (HR) values and on their variability was examined in ambulant patients with essential hypertension, using the Oxford method to obtain continuous intraarterial recording and a computer to have a beat-to-beat analysis of the data. The recording was carried out without treatment and after 10 days' administration of N once daily by mouth (dose range: 80-320 mg). After N, 24-hour BP and HR were reduced by 17 +/- 3% and 27 +/- 4% respectively as compared to before N, the effect being similar for both systolic and diastolic BP. The hypertension and bradycardia were significantly more marked during the day than during the night, neither showing any attenuation in the hours furthest from the administration of the drug. During N, there was a reduction in the 24-hour variation coefficient for HR but the reduction was limited to the longer term component of this phenomenon, the moment-to-moment variations remaining unaffected. The long- and short-term variation coefficients for BP were not modified under N. These findings suggest that N once a day can reduce BP for 24 hours in ambulant hypertensive patients. The lack of alteration in variability of BP and moment-to-moment HR suggests that the hypotension is achieved without interfering with the mechanisms involved in cardiovascular homeostasis.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Baroreceptor control of the circulation in man. An update.

In recent years assessment of baroreflex cardiovascular control in humans has received growing attention for two major reasons, i.e. 1) the availability of new techniques to evaluate this reflex function and 2) the possibility that a baroreflex alteration might play a role in the clinical evolution of cardiovascular diseases. This paper will briefly examine the alterations in baroreflex function in a variety of diseases affecting the circulation. In particular it will be focused on 1) the baroreflex control of heart rate and microneurographically measured muscle sympathetic nerve traffic in human hypertension, 2) the impairment of this reflex homeostatic function occurring in congestive heart failure of different clinical severity and finally 3) the transient alterations in baroreflex-heart rate control occurring in man in the acute post-myocardial infarction phase and during episodes of spontaneous myocardial ischemia.

Baroreflex↗
PubMedDate not supplied

Arterial distensibility in cardiovascular diseases.

Several pathological conditions affecting the cardiovascular system are characterized by a dysfunction of the viscoelastic properties of the arterial vessels and, in particular, of arterial distensibility and compliance. These alterations have pathophysiological and clinical relevance because both distensibility and compliance play a key role in cardiovascular homeostatic control by modulating a number of important parameters, such as arterial impedence, cardiac afterload and myocardial oxygen consumption. This paper, after briefly mentioning the technical progress recently achieved in the assessment of arterial compliance in man, will examine the alterations in this vascular function which take place in hypertension, hypercholesterolemia, diabetes and congestive heart failure. It will also discuss the mechanisms potentially responsible for these alterations and the effects of cardiovascular drugs commonly employed in the treatment of these diseases.

Arteries↗
PubMedDate not supplied

[The role of angiotensin II inhibitors in arterial hypertension: clinical trials and guidelines].

Despite many outstanding favorable results obtained over the past 30-40 years in the treatment of hypertension, several goals of antihypertensive therapy remain unmet. One of them concerns the epidemiological evidence that only 25% of treated hypertensive patients have optimal blood pressure control. Clinical use of new antihypertensive drugs is aimed at achieving the above-mentioned goals, and in particular, at providing more effective blood pressure control, greater cardiovascular protection, and better patient compliance to antihypertensive drug treatment. This paper will examine the main clinical features of angiotensin II receptor blockers, highlighting the results of clinical studies performed thus far, and the main goals of ongoing clinical trials with these drugs. Finally, the role of these compounds in the therapeutic approach to the hypertensive state according to the recent guidelines of the World Health Organization/International Society of Hypertension will be outlined.

Angiotensin II↗
PubMedDate not supplied

[Semi-automatic determination of blood lactate during hypoglycemic treatment with biguanides].

Blood lactate levels were determined by Lactate Analyzer 640 Kontron in 67 adult insulin-independent diabetics during hypoglycemic treatment with usual therapeutical doses of phenformin. In 5 cases were found lactate values above 2 mmol/l and, in consideration of accompanying conditions prone to lactic acidosis, the drug was discontinued. However, the mean value of blood lactate in diabetics treated with phenformin was not significantly different from that found in a group of insulin-treated diabetics. The semiautomatic determination of blood lactate is proposed as a rapid screening of possible candidates for lactic acidosis during biguanide treatment.

Autoanalysis↗