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Biomedical subjects

G Rizzo

Publications and source records attributed to G Rizzo.

At least 217 records · Page 12Linked to original sources
PubMed1988

Plasma protein binding of zolpidem in liver and renal insufficiency.

Similar degree (65-66%) of binding of zolpidem (0.1 microgram/ml) was found with physiological concentrations of isolated human albumin (40 g/l) or alpha-1-acid glycoprotein (1 g/l). Zolpidem binding was studied in plasma from 6 healthy subjects, 12 patients with renal failure, 12 patients with liver cirrhosis and 12 chronic uremics maintained on hemodialysis as well as in 12 serum samples from the placental cord. The unbound fraction (mean +/- s.e.m.) was 8.1 +/- 0.2% (healthy volunteers), 10.8 +/- 0.4% (renal failure), 11.3 +/- 0.7% (liver cirrhosis); 14.9 +/- 1.0% (before hemodialysis); 9.8 +/- 0.4% (after hemodialysis) and 13.2 +/- 0.9% (placental cord). All values, except those after hemodialysis, were significantly different (Dunnett's test) from those of the volunteers. Hemodialysis significantly increased the binding of zolpidem in plasma. The kinetics of protein binding of zolpidem were investigated in plasma samples from 3 healthy subjects. The average number of binding sites was 1.83 x 10(-7) mol per gram protein and the average association constant was 4.49 x 10(5) M-1.

Adult↗
PubMed1987

Modulation of echocardiographic parameters by fetal behaviour.

In order to verify if fetal behavioural states could affect cardiac parameters, thirty-one healthy fetuses were studied near term. We evaluated systolic time intervals (pre-ejection period and ventricular ejection time), M-mode parameters (fractional shortening and mean circumferential shortening) and Doppler flow velocities (mean peak velocity of aortic and pulmonary arteries) of left and right ventricles. Both fetal breathing movements and fetal heart rate patterns seem to modify these parameters with an increase of cardiac contractility during active phases of fetal behaviour.

Blood Flow Velocity↗
PubMed1987

Fetal behaviour in growth retardation: its relationship to fetal blood flow.

The fetal behaviour of asymmetrical growth retarded fetuses was compared with that of a control group of healthy fetuses. Fetuses underwent simultaneous cardiotocographic and echographic examinations for two consecutive hours at 36-38 weeks of gestation. The distribution of gross fetal body movements, fetal breathing movements and fetal eye movements was analysed during the different fetal heart rate patterns. Furthermore, the incidence and organization of fetal behavioural states was investigated. The degree of vascular peripheral resistance was also evaluated by means of pulsed doppler ultrasonic equipment. Growth retarded fetuses were divided into two groups on the basis of the presence or absence of end diastolic flow in the fetal thoracic descending aorta. Growth retarded fetuses showed a delay in the integration of behavioural patterns and a lower coincidence of behavioural states. These findings are particularly evident in the fetuses with a severe increase of peripheral vascular resistance (absence of end diastolic flow in descending aorta). Thus, we suggest that a delay in central nervous system development is present in asymmetrical growth retarded fetuses and that there is a possible relationship of this delay to the degree of peripheral vascular resistance.

Blood Circulation↗
PubMed1987

Longitudinal assessment of blood flow velocity waveforms in the healthy human fetus.

A longitudinal study was carried out on 30 healthy fetuses in order to assess the modifications of fetal blood flow throughout pregnancy. The pulsatility index was evaluated at two-week intervals by means of pulsed Doppler equipment. In the umbilical artery measurements were performed from 20 weeks onwards, whereas in the descending aorta and internal carotid artery analysis started from 26 weeks onwards. A decrease of the pulsatility index in umbilical artery and in the ratio between the pulsatility indexes in umbilical artery and internal carotid artery was found over the second half of pregnancy.

Aorta, Thoracic↗
PubMed1987

Effect of naloxone on fetal behavior near term.

Fetal behavior was studied after intravenous administration of either 0.4 mg of naloxone or an equal volume of saline solution in 54 healthy pregnant women near term. The number, duration, and amplitude of fetal heart rate accelerations increased after naloxone injection. The incidence of both gross fetal body movements and fetal breathing movements increased, especially in the first hour after naloxone administration. The distribution of fetal behavioral states was modified with a prevalence of active sleep and active awake states compared to the quiet sleep state. These data suggest that endorphins could be involved in the modulation of fetal behavior.

Adult↗
PubMed1987

Nuclear and cytosolic estrogen receptors in human colon carcinoma and in surrounding noncancerous colonic tissue.

The measurement of estrogen as well as progesterone receptors has been applied clinically to predict the effectiveness of endocrine therapy in patients with breast or endometrial carcinoma. The presence of cytosolic estrogen receptors in human colorectal carcinomas has been reported by several different groups during the past 10 yr. The aim of our current study was to evaluate the estrogen binding activity in the nuclear and cytosolic fractions of these carcinomas, as well as in surrounding noncancerous colonic tissue. Twenty-six patients, operated on for colorectal carcinoma, were studied: 16 were men and 10 were postmenopausal women, mean age 61 yr (range 43-78 yr). In neoplastic tissue, cytosolic estradiol receptors were detected in 42.3% of the patients (women 40%, men 43.7%). The values for cytosolic estrogen receptor ranged from 118 to 1214 fmol/g wet colon. Nuclear estrogen receptors were detectable in 46.1% of the patients (women 40%, men 50%) and their values displayed a range from 3.4 to 2554 fmol/g wet colon. In 30.7% of the patients, both nuclear and cytosolic receptors were demonstrated. In 38.4% of the patients, receptors were found in neither cytosol nor nuclei. Receptor positivity in men was most frequently associated with tumors removed from the rectum, and those with Dukes' classification of C1. In the surrounding noncancerous tissue cytosolic estrogen receptors were also detected (range 133-1105 fmol/g wet colon) and were present in 34.6% of the patients (women 30%, men 37.5%). Nuclear estrogen receptors (range 225-1105 fmol/g wet colon) were detected in 57.6% of the patients (women 40%, men 68.7%). In 23% of the patients, both nuclear and cytosolic receptors were demonstrated. In 30.7% of the patients, no receptors were found in either cytosol or nucleus. Therefore, the presence of cytosolic or nuclear estrogen receptors, or both, in 61.6% of human colorectal cancer specimens emphasizes the need to evaluate both forms of these receptors for studies of potential hormone dependence in these tumors.

Adenocarcinoma↗
PubMed1987

Heart rate variability signal processing: a quantitative approach as an aid to diagnosis in cardiovascular pathologies.

The heart rate variability (HRV) signal carries important information about the systems controlling heat rate and blood pressure, mainly elicited by autonomic nervous system (sympathetic and parasympathetic) controls. The present paper illustrates methods of HRV signal processing by using autoregressive (AR) modeling and power spectral density estimate. The information enhanced in this way seems to be particularly sensitive in discriminating various cardiovascular pathologies (hypertension, myocardial infarction, diabetic neuropathy, etc.). This method provides a simple non-invasive analysis, based on the processing of spontaneous oscillations in heart rate. Particular emphasis is directed to the algorithms used and to their direct application by using proper computerized techniques: only a few paradigmatical examples will be illustrated as preliminary results.

Cardiovascular Diseases↗
PubMed1987

Utero-placental blood flow velocity waveforms as predictors of pregnancy-induced hypertension.

Sixty high-risk pregnancies were studied in order to define the validity of the analysis of utero-placental blood flow velocity waveforms in early screening for developing hypertensive diseases. Recordings were obtained at 18-20 weeks gestation, in normotensive patients, using a pulsed duplex Doppler system at the level of uterine vessels. The patients (n = 22) who developed hypertension showed a higher resistance index value (p less than 0.001) than normotensive patients (n = 38). The validity of uteroplacental waveform analysis was as follows: specificity = 84.2%; sensitivity = 63.6%; positive predictive value = 70%; negative predictive value = 80%; accuracy = 76.6%. The high specificity attained suggests that this test can adequately identify, among a high-risk population, patients destined to remain normotensive during pregnancy.

Arteries↗
PubMed1987

Plasma protein binding of clonazepam in hepatic and renal insufficiency and after hemodialysis.

The plasma protein binding of clonazepam was investigated in healthy volunteers, cirrhotic patients, chronic uremic patients maintained on hemodialysis, and patients with reduced renal function. Each group consisted of six subjects. The unbound fraction of clonazepam (mean +/- SEM) was 13.9 +/- 0.2% in volunteers. 17.1 +/- 1.0% in cirrhotic patients, 1.56 +/- 0.5% before and 12.2 +/- 0.4% after hemodialysis in chronic uremic patients, and 16.0 +/- 0.7% in patients with poor renal function. The figure for the healthy subjects was significantly different from that of cirrhotic patients only. Binding of clonazepam to albumin and alpha 1-acid glycoprotein was also studied. Clonazepam bound preferentially to albumin.

Adult↗
PubMed1987

Abnormal fetal cerebral blood flow velocity waveforms as a sign of an aneurysm of the vein of Galen.

A cerebral midline cystic lesion was detected by real-time ultrasound in utero in the absence of other congenital abnormalities. Pulsed Doppler ultrasound assessment of fetal circulation demonstrated normal peripheral and intracardiac hemodynamics associated with decreased cerebral vascular resistance. Furthermore, a markedly turbulent flow pattern was evidenced within the cerebral lesion. The presence of a cerebral arteriovenous malformation with an aneurysm of the vein of Galen was suggested and the provisional diagnosis was later confirmed by computed tomography and carotid angiography performed after birth.

Adult↗
PubMed1987

Development of behavioral states in hydrocephalic fetuses.

Behavioral states observations were carried out in 12 hydrocephalic fetuses by means of a computerized system. Recordings of behavioral parameters, including fetal heart rate, gross body movements, breathing movements and eye movements, were performed at 2-week intervals from 30 weeks of gestation onwards. The hydrocephalic fetuses showed quantitative and qualitative differences in their motor behavior in comparison to healthy fetuses of equivalent gestational age. Similarly the appearance of behavioral states was delayed in hydrocephalic fetuses. Furthermore, an increased discordance between the behavioral parameters was evidenced. The degree of discordance seems to be related to the severity of neonatal outcome suggesting a possible estimation of CNS dysfunction by means of behavioral state analysis.

Brain↗
PubMed1987

Effects of nifedipine on umbilical artery velocity waveforms in healthy human fetuses.

The purpose of this investigation was to analyze the changes in umbilical artery (UA) velocity waveforms after administration of nifedipine in 30 healthy pregnant women. The effects on fetal and maternal heart rates and maternal arterial pressure were also analyzed. The patients included in this double blind study received sublingually either 10 mg of nifedipine or a placebo. A transient fall of the UA resistance (as expressed by the pulsatility index) occurred 15 min after nifedipine administration, but resistance returned to control values after 90 min. Maternal heart rate increased after nifedipine administration and returned toward the control value by 45 min. Fetal heart rate and maternal mean arterial pressure did not change significantly. These data suggest a possible use of nifedipine to normalize the UA velocity waveform in pregnancies complicated by hypertension and fetal growth retardation.

Blood Flow Velocity↗
PubMed1987

Loss of circadian rhythms of fetal behaviour in a totally adrenalectomized pregnant woman.

Fetal heart rate and fetal movements were recorded over a 24-hour interval in a totally adrenalectomized pregnant woman at term. Cortisol, ACTH, unconjugated estriol and 17 beta-estradiol were contemporaneously measured every 2 h in the maternal peripheral plasma. Owing to the substitution therapy the patient showed a loss of circadian variations of all the hormones investigated. Moreover, the circadian rhythms of fetal heart rate and fetal movements, usually present at term, were no longer evident. We can thus suggest that the circadian variations of plasma maternal cortisol could affect the alternations of fetal behaviour.

Adrenalectomy↗