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Biomedical subjects

L Donato

Publications and source records attributed to L Donato.

At least 19 recordsLinked to original sources
PubMed1992

Regional myocardial blood flow and coronary reserve in hypertensive patients. The effect of therapy.

Patients with essential arterial hypertension demonstrate abnormal vasodilator capacity either during increased cardiac metabolic demand or during pharmacological vasodilation. Structural and functional damage to the coronary microcirculation has been proposed as one of the major causes of impaired coronary reserve in this disease. To assess the role of microvascular impairment in regional myocardial blood flow (MBF), 27 patients with essential hypertension were evaluated by dynamic positron emission tomography (PET) at rest, during atrial pacing and after dipyridamole infusion and compared with 13 healthy subjects. All patients had normal coronary arteries, 17 had moderate to severe hypertension and 10 had mild hypertension. Baseline mean MBF of 0.97 +/- 0.25 ml/min/g was significantly increased to 1.60 +/- 0.38 during atrial pacing and 2.35 +/- 0.95 after dipyridamole infusion (p < 0.01); however, mean flow during atrial pacing and after dipyridamole infusion was significantly lower than in healthy subjects (2.15 +/- 0.73 and 3.71 +/- 0.86 ml/min/g, p < 0.05 and p < 0.01, respectively). The MBF response to atrial pacing and dipyridamole infusion was similarly depressed in patients with mild and severe hypertension. The study was repeated after 6 months of antihypertensive treatment with the calcium antagonist verapamil or the angiotensin converting enzyme (ACE) inhibitor enalapril in a subgroup of 20 patients as part of a randomised, single-blind clinical trial. This study is still in progress; the initial 16 patients treated with verapamil or enalapril showed an obvious improvement in MBF values during atrial pacing and after dipyridamole infusion after 6 months of therapy (mean MBF: 2.10 +/- 0.64 and 2.99 +/- 1.63 ml/min/g, respectively, p < 0.05 vs pretreatment values). In conclusion, obvious impairment of MBF during atrial pacing and after dipyridamole infusion was observed in hypertensive patients with normal coronary arteries and this appeared unrelated to the severity of hypertension. Therapy with verapamil or enalapril improved coronary reserve and MBF response to an increase in myocardial oxygen demand.

Adult↗
PubMed1992

[Medical treatment of chylous effusions in newborn infants. Apropos of 3 cases].

BACKGROUND: Chylous effusions are the most frequent cause of non immunologic hydrops fetalis. They can be recognized antenatally by ultrasonography. Their evacuation is sometimes necessary and medical treatment often effective. CASE REPORTS: Case n. 1: fetal ascites was detected by ultrasonography at the 30th week of gestation. Paracentesis was performed at 36 weeks, followed 3 days later by spontaneous delivery. The newborn was fed milk formula. A second paracentesis showed a milky fluid, rich in cholesterol, triglycerides and chylomicrons. The child was fed formula rich in medium-chain triglycerides and the chylous ascites disappeared completely within 2 weeks. Case n. 2: a diagnosis of bilateral hydrothorax and hydramnios was made at the 27th week of gestation. An in utero evacuation of the hydrothorax performed at the 30th week was ineffective and a pleuro-amniotic drainage was performed 2 weeks later. The baby was born at the 35th week, and presented a moderate respiratory distress due to the hydrothorax and ascites. Aspiration of the thoracic fluid confirmed its chylous origin. The chylous effusions completely disappeared when the child was fed a high medium chain triglycerides diet. A lymphedema of legs appeared at the age of 1 month. Case n. 3: ascites, hydramnios, hydrothorax and peripheral edema were found at the 21st week of a third pregnancy (the 2 first pregnancies were complicated by lethal hydrops fetalis). Bilateral hydrothorax and peripheral edema were found again after birth at the 37th week. Diuresis and albumin-infusion led to recovery, but chylothorax and chylous ascites reaccumulated after introduction of milk formula, despite repeated evacuations and feeding medium-chain triglycerides formula. The thoracic fluid remains chylous at the age of 9 months. CONCLUSIONS: In utero, and sometimes post-natal, evacuation of fluid present in the thoracic and peritoneal cavities can be necessary, depending of the functional tolerance. Medical management including feeding a low fat and/or high medium-chain triglycerides diet, and sometimes temporary total parental nutrition, is necessary, together with salt restriction, diuresis and albumin infusion as required. Most cases recover spontaneously or as a result of therapy within a few weeks.

Chylothorax↗
PubMed1992

[Tracheal compression by an aberrant brachiocephalic trunk: diagnosis by magnetic resonance].

In a full-term infant who underwent surgery for type III esophageal atresia, attempts to remove the tracheal tube postoperatively failed. Bronchoscopy disclosed external compression of the trachea in the chest. Selection of the investigations most likely to provide the etiologic diagnosis was discussed. Because of the patient's poor general condition, MRI of the mediastinal area was performed first and showed an abnormal origin of the brachiocephalic trunk which was the cause of tracheal compression. No attempt at corrective surgery was made and the patient was successfully extubated at four months of age.

Airway Obstruction↗
PubMed1991

[Biological indicators of bacterial infection in newborn infants].

Biological markers of neonatal bacterial infection are useful if they bring early indications and if they are sensitive and specific. There are two kinds of tests: hematological signs and acute phase proteins. The most specific hematological signs are, in chronological order: leuconeutropenia--myelemia--neutrophilic polynucleosis. Gestational and post-natal ages have to be taken in consideration for correct interpretation of white cell count and differential. Several acute phase proteins increase in infected newborns: fibrinogen, C reactive protein, orosomucoïd. If determined quantitatively, C reactive protein is a sensitive, specific and early marker allowing, in addition, to follow the reaction to treatment: the return to normal range of CRP and later of orosomucoïd attest for recovery. These biological tests have to be sequentially determined during the first days in order to obtain a maximal information.

Aging↗
PubMed1991

[Mediastino-pulmonary sarcoidosis in children. Clinical study, analysis of data of bronchoalveolar fluid lavage and respiratory function tests, therapeutic trends].

A series of 27 children (mean age: 12 yrs, 5 mos.) presenting with thoracic sarcoidosis is reported. This series, collected from 1961 to 1988 shows the rarity of the disease at that age. However the low rate of asymptomatic forms (22%) suggests that the frequency of the disease is underestimated, as it is not diagnosed. The histological proof is necessary for the diagnosis. When peripheral lesions available for biopsy are lacking, a liver needle biopsy is helpful (93% of positivity). This study shows the frequency of multivisceral types, the intensity of the macrophagic and lymphocytic alveolitis. The therapeutic indications depend on the comparison of the radiological stage, the results of pulmonary function tests (PFT), those of the bronchoalveolar lavages (BAL) and of the serum granulomatous activity markers, especially concerning angiotensin converting enzyme (ACE). When present at the beginning of evolution, several risk factors lead to use a corticosteroid treatment: age of onset before 4 years, multivisceral involvement, presence of functional pulmonary signs, delayed diagnosis and onset of treatment, impaired respiratory function (especially concerning the alveolo-capillary diffusion), PMN cells greater than or equal to 2% in the initial BAL, and IgG proteins greater than 4 SD. Thus sarcoidosis in children differs from that seen in adults as it has a more marked evolutive tendency and leaves severe sequelae in one third of patients.

Adolescent↗
PubMed1991

Effects of Vaccinium Myrtillus anthocyanosides on arterial vasomotion.

The effects of Vaccinium Myrtillus anthocyanosides (Myrtocyan, VMA; CAS 84082-34-8) on arteriolar vasomotion were assessed in cheek pouch microcirculation of anesthetized hamsters and in skeletal muscle microvasculature of unanesthetized hamster skin fold window preparation. Intravenously injected VMA induced vasomotion in cheek pouch arterioles and terminal arterioles with higher frequency in smaller vessels. In the skeletal muscle arteriolar networks VMA increased vasomotion frequency and amplitude in all vessel orders. The results indicate that VMA are effective in promoting and enhancing arteriolar rhythmic diameter changes, that play a role in the redistribution of microvascular blood flow and interstitial fluid formation.

Animals↗
PubMed1991

[Cystic fibrosis and bronchial hyper-reactivity].

An increased airway responsiveness to inhaled nonspecific stimuli has been often observed in cystic fibrosis patients. But bronchial hyperreactivity in such patients is due, in most cases, to damaged bronchial mucosa rather than to coexistent asthma, and it remains under question whether or not bronchodilators are of help in cystic fibrosis. Indeed some authors reported adverse effects after inhalation of beta-mimetic drugs. This behavior seems to be due to an "instability" of the bronchial walls in cystic fibrosis. Nevertheless other studies showed that bronchodilators could be of help when administered in some cases and during definite periods in the evolution of the disease. Indeed, variability in responsiveness to bronchodilator drugs is one of the features of cystic fibrosis and therapy must be adjusted to this variability in every patient. In any way, pulmonary functional tests must be performed before and after administration of a bronchodilator drug and before beginning such therapy.

Asthma↗
PubMed1991

[Magnetic resonance imaging in the diagnosis of retrotracheal pulmonary artery].

The authors report the case of a 3-month-old infant with a history of interventricular septal defect with pulmonary arterial hypertension. This child had pulmonary symptomatology (dyspnea, recurrent bronchitis, acute attacks of asphyxia) which it was possible to link to a retrotracheal left pulmonary artery by magnetic resonance imaging (MRI). Classical investigations (upper GI barium series and chest X-ray) were suggestive of a bronchogenic cyst type abnormal pulmonary structure. Angiography confirmed the MRI diagnosis. In this case the infant also had tracheal lesions (lower tracheal hypoplasia) which required further evaluation by fibroscopy and bronchography. Thus MRI shows itself to be a useful investigation in the study of basic vascular abnormalities.

Arterial Occlusive Diseases↗
PubMed1990

Superposition of arteriolar vasomotion waves and regulation of blood flow in skeletal muscle microcirculation.

In skin muscle microcirculation of Syrian hamsters, rhythmic diameter changes were studied along the arteriolar network, under normoxic conditions, at rest. A teflon coated-aluminum chamber was implanted in the dorsum skin of animals. The microcirculation was investigated using intravital microscopy technique. Vessel diameters were determined by a computer-assisted method. Power spectrum analysis of vasomotion recordings was carried out with Fast Fourier Transform and Autoregressive modelling. To determine vasomotion waveform spreading, cross-spectral data (amplitude and phase) were computed, using the modified periodogram method (FFT). The arterioles were classified according to Strahler's method. Order 1 vessels (diameter: 7.50 +/- 1.16 microns) showed the highest frequency, 4-15 cycles per min, and percentage amplitude in the range 60-100%. Order 2 and 3 arterioles had intermediate frequencies, and amplitude in the range 50-100%, and 15-50%, respectively. The largest order 4 vessels (diameter: 28.97 +/- 9.55 microns) had the lowest frequency, 0.3-3 cpm, and amplitude in the range 5-20%. In most networks, cross-correlation analysis revealed two groups of frequency components. Low frequency group was propagated from order 4 and 3 vessels downstream. High frequency components were transmitted upstream from order 1 and 2 arterioles. Therefore, a complex superposition of waveforms resulted from the activity of discrete points along the microvasculature. In conclusion, rhythmic diameter changes of arterioles in skeletal muscle microcirculation regulate blood flow distribution in capillary units and control tissue oxygenation.

Animals↗
PubMed1990

Electrocardiographic changes suggestive of myocardial ischemia elicited by dipyridamole infusion in acute rejection early after heart transplantation.

Acute cardiac rejection, syndrome X, and arterial hypertension can induce small vessel damage and, therefore, restriction of coronary reserve in the presence of normal epicardial coronary arteries. A characteristic response pattern to dipyridamole (DIP) infusion has been previously described in syndrome X and arterial hypertension: ST segment depression without any measurable systolic dysfunction. The aim of this study was to establish whether acute cardiac rejection might induce electrocardiographic alterations during DIP infusion. Changes in the 12-lead electrocardiogram and two-dimensional echocardiogram during high-dose DIP infusion (up to 0.84 mg/kg in 10 minutes) were evaluated within 24 hours of endomyocardial biopsy in 14 transplanted patients. A total of 47 biopsy-controlled DIP studies were performed within 5 weeks after cardiac transplantation. For each patient, at least 7 days elapsed between two consecutive studies. Electrocardiographic and echocardiographic tracings were analyzed without prior knowledge of endomyocardial biopsy findings. No remarkable side effects occurred in any case, so that the DIP study could be completed in all patients. A diagnostic (greater than 0.1 mV) ST segment depression was found in 11 studies. The sensitivity and specificity of DIP-induced ST segment depression for the detection of biopsy-proven acute rejection were 72% and 94%, respectively. These data show that DIP stress is feasible and safe in transplanted patients and that acute cardiac rejection can be accompanied by DIP-induced ST segment depression without detectable impairment in systolic function. These changes might provide noninvasive markers for surveillance of rejection.

Adult↗
PubMed1990

Increased circulating concentrations of interleukin 2 receptor during rejection episodes in heart- or kidney-transplant recipients.

Concentrations of interleukin 2 receptor (sIL-2R) have been suggested as a marker of rejection episodes after organ transplantation. To evaluate the analytical performance of a "sandwich-type" enzyme immunoassay method for sIL-2R and to verify whether increased concentrations of sIL-2R might be a useful marker of allograft rejection, we quantified sIL-2R in serum samples from heart- or kidney-transplant patients. The mean (+/- SD) pre-transplant value of sIL-2R (592 +/- 209 kilo-units/L) in heart-transplant patients was significantly higher (P less than 0.01) than that observed in controls (350 +/- 101 kilo-units/L). After heart transplantation, the concentrations of sIL-2R slowly decreased to baseline in successfully treated patients but increased significantly (1129 +/- 215 kilo-units/L; P less than 0.01) during acute rejection crisis. However, severe infections were also associated with a significant increase of sIL-2R, so the sIL-2R test is not specific for allograft rejection. The mean pre-transplant concentration of sIL-2R was also increased (1943 +/- 878 kilo-units/L) in 26 renal-transplant patients; after transplantation, this value returned to normal, as did that for creatinine, but persisted steadily high in five patients who experienced acute tubular necrosis. In this group of patients, the sIL-2R concentration increased by 1.5- to fourfold, both during acute rejection episodes and in clinically evident infection; thus measurement of creatinine and sIL-2R concentrations can help to distinguish between rejection, infection, and cyclosporine toxicity. In two episodes of mild cyclosporine-induced nephrotoxicity, we observed slight increases in serum creatinine (which returned to baseline when the cyclosporine dose was decreased) not associated with an increase in sIL-2R. We conclude that systematic monitoring of sIL-2R together with other biochemical and clinical markers may be useful in the management of kidney-transplant patients.

Adult↗
PubMed1990

Simultaneous in vitro and in vivo validation of nitrogen-13-ammonia for the assessment of regional myocardial blood flow.

Measurement of myocardial blood flow by 13NH3 relies heavily on the assessment of both the input function and the variable tissue extraction fraction. In six open-chest dogs, myocardial and arterial 13NH3 activity was measured both by in vitro sampling and by in vivo positron emission tomography (PET). Regional myocardial blood flow was forced to vary in the range 0.2-5 ml/min/g and actual values were assessed by in vitro counting of 153Gd microspheres. The ammonia input function was processed by: (a) total curve integration; (b) curve integration for 2 min; (c) integral of a fitted curve (gamma variate in vivo and exponential of the downslope in vitro). Method C brought to regional flow values which best approximated microspheres data. The in vitro correlation allows for correcting in vivo values for the flow-dependent extraction fraction. The method can be easily applied for regional myocardial blood flow measurements with PET in human studies.

Algorithms↗
PubMed1989

Ultrafiltration: a rational treatment for heart failure.

Patients with late-stage congestive heart failure with significant fluid overload respond well to ultrafiltration. The response is relatively long-standing and includes enhanced responsiveness to diuretics. Ultrafiltration is simple and highly cost effective. Furthermore, it possesses many advantages over massive or drastic pharmacological therapy. In the following paper, we report our own experience and review the world literature.

Blood Volume↗
PubMed1989

Seasonal influences on blood pressure in high normal to mild hypertensive range.

To investigate the seasonal influences on various arterial blood pressure measurements, 22 subjects in the high normal to mild hypertensive range were examined twice following the same protocol. In one group (13 subjects), measurements were first done in warm conditions and repeated 5-7 months later in cold conditions; in the second group (nine subjects) a reverse sequence was followed. Blood pressure was measured under casual conditions during a hand grip exercise test, mental arithmetic test, and submaximal multistage bicycle exercise test; during the following 24 hours, blood pressure was measured serially with a noninvasive ambulatory blood pressure recorder. Daily outdoor maximum and indoor laboratory temperatures were also obtained. In the cold season, significantly higher values (on the average by 5-10 mm Hg, p less than 0.01) were obtained in both groups for mean diastolic daytime blood pressure. For other measurements, a trend toward higher values in the cold season was observed in both groups, although statistical significance was not obtained in all instances. For nighttime measurements, irrespective of the seasonal sequence, lower values were observed in the second session. Significant correlations were found between the differences in the average daytime ambulatory blood pressures and the corresponding changes of daily maximum outdoor temperatures after 5-7 months. These observations indicate that arterial blood pressure may be strongly influenced by environmental temperature. This phenomenon should be taken into account both in the evaluation of the individual hypertensive patients and in the design and analysis of studies on arterial hypertension, especially when ambulatory blood pressure techniques are employed.

Adolescent↗