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Biomedical subjects

M Morello

Publications and source records attributed to M Morello.

At least 19 recordsLinked to original sources
PubMed2006

Effects of chronic internal alpha irradiation on physiology, growth and reproductive success of Daphnia magna.

Daphnids were chronically exposed to waterborne Am-241, an alpha-emitting radionuclide, ranging in concentration from 0.4 to 40 Bq ml(-1). Am-241 amounts were monitored in the medium, daphnid tissues and cuticles. Corresponding average dose rates of 0.02, 0.11 and 0.99 mGy h(-1) were calculated for whole organisms with internal alpha-radiation contributing 99% of total dose rates. Effects of internal alpha irradiation on respiration and ingestion rates, adult, egg and neonate individual dry masses, fecundity and larval resistance to starvation were examined in 23-day experiments. Daphnids showed increased respiratory demand after 23 days at the highest dose rate, suggesting increased metabolic cost of maintenance due to coping with alpha radiological stress. Although no effect was detected on ingestion rates between contaminated and control daphnids, exposure to dose rates of 0.11 mGy h(-1) or higher, resulted in a significant 15% reduction in body mass. Fecundity remained unchanged over the 23-day period, but individual masses of eggs and neonates were significantly smaller compared to the control. This suggested that increased metabolic expenditure in chronically alpha-radiated daphnids came at the expense of their energy investment per offspring. As a consequence, neonates showed significantly reduced resistance to starvation at every dose rate compared to the control. Our observations are discussed in comparison with literature results reported for cadmium, a chemical toxicant which affects feeding activity and strongly reduces individual energy uptake.

Age Factors↗
PubMed2006

The Myocardial Performance Index detects chronic cardiac allograft dysfunction sooner than other methods.

AIM: Many noninvasive techniques have been proposed for the early detection of chronic heart graft dysfunction. Diastolic dysfunction may precede systolic dysfunction, and often is prominent; therefore, the aim of the study was to investigate the clinical and prognostic value of a Doppler-derived index of both systolic and diastolic function in heart transplanted patients (Myocardial Performance Index, MPI). METHODS: The MPI was measured in 63 consecutive patients (mean age 55 years, 49 men and 14 women) in sinus rhythm with an orthotopic heart transplantation for at least 1 year (mean 5.3 years) and in 63 age and sex-matched controls. A complete clinical examination was performed at the time of enrollment and was repeated after 3 months. RESULTS: At 3 months, 11 patients (17.5%) presented events (heart failure, hospitalisation or cardiac death). Patients were divided into 2 groups: Group A (52 patients) without events in the follow-up and Group B (11 patients) with events. The values of MPI in Group B (0.55+/-0.19) were significantly higher than values in Group A (0.34+/-0.18, P=0.001). Whereas the values of the index did not differ significantly between Group A and control group (0.34+/-0.18 vs 0.33+/-0.10, P=NS). In the univariate analysis, the population of heart transplanted patients was dichotomised in subgroups by a cut-off MPI of 0.47 and a cut-off ejection fraction (EF) of 50%. Nine patients (41%) with MPI=or>0.47 presented events, while only 2 patients (5%) with MPI<0.47 had any event (P<0.001; c2 12.9). Six patients (85%) with EF<50% had events, while only 5 patients (9%) with EF=or>50% had an event (P<0.001; c2 14). In the multivariate analysis only MPI (chi squared=22.6, P=0.018) and EF (chi squared=20.8, P=0.025) were significant independent predictors of heart failure or cardiac death. By looking at Kaplan-Meyer curves, MPI seems to be better than EF in the earlier detection of graft dysfunction. CONCLUSION: MPI, as a combined systolic and diastolic index, may detect graft dysfunction earlier than EF.

Chronic Disease↗
PubMed2006

Benign paroxysmal torticollis of infancy. A case report.

Benign paroxysmal torticollis of infancy is a benign, rare, probably under-recognised disorder, characterized by recurrent episodes of head tilting. The diagnosis is primarily one of pattern recognition and exclusion of alternatives conditions; other symptoms, such as vomiting, pallor and eyes' rotation, may be associated with or rapidly follow the attack, leading to misdiagnosis of this disease. The exact pathogenesis of benign paroxysmal torticollis is not clear, but a close relationship with childhood periodic syndromes is supposed. Due to the difficulty in defining the disease, this event has implications with respect to the training and education of practice providers and emergency physicians. We describe the case of a 7-month-old infant with benign paroxysmal torticollis recently observed, discuss the clinical presentation and review the literature.

Female↗
PubMed2006

Severe degenerative aortic stenosis: when a senile patient is a candidate for surgery.

Senile aortic stenosis is characterized by calcific degeneration of the valve that prevents the full opening of the cusps in systole. The disease may be silent for many years despite the presence of severe flow obstruction and generally is associated with aortic regurgitation and calcification of the coronary arteries. The continuous increase of the aged population with aortic stenosis entails difficult decisions in selecting the candidates for aortic valve replacement in order to optimize the timing for surgery. Although clinical examination is still fundamental for the diagnosis of the disease and the screening of the population, noninvasive assessment by Doppler echocardiography has transformed the management of these patients. The procedure allows better identification of patients who may benefit from valve replacement in particular in the setting of a ''low output/low gradient'' state and permits a follow-up of the progression of the disease in patients who are not yet candidates for surgery. It also allows a decrease in the utilization of invasive hemodynamics becoming a cost benefit tool for the health system. When performed properly, it is relatively time consuming, needs experience but offers major anatomic and hemodynamic data. Under these circumstances, cardiac catheterization is required only in cases when there is discordance between the clinical assessment and cardiac ultrasound evaluation. In this review we summarize the prevalence and significance of the disease in the elderly population and the use of all recent echocardiographic data that may help select the true candidates for surgery.

Aortic Valve Stenosis↗
PubMed2005

Am-241 remobilization in a calcareous soil under simplified rhizospheric conditions studied by column experiments.

The effects of simplified rhizospheric conditions on the leaching of (241)Am from a calcareous soil, freshly contaminated, were investigated in batch and column experiments. Glucose and/or citrate were used as artificial exudate solutions at concentrations ranging from 10(-4) to 10(-2)moldm(-3). Am desorption, expressed in terms of distribution coefficients, varied from K(d)>10(4)dm(3)kg(-1) corresponding to a majority of experimental conditions, to K(d)</=10(2)dm(3)kg(-1) when citrate combined or not with glucose was used at >/=10(-2)moldm(-3). Soil columns revealed successive steady states coupled with transitory episodes, the latter represented up to 90% of the total Am release. (241)Am fractions with different behaviours were thus highlighted in columns whereas batch only accounted for highest Am mobile fractions. The implications of the different processes are discussed in terms of modelling approach and risk assessment.

Adsorption↗
PubMed2005

Influence of rainfall characteristics on elimination of aerosols of cesium, strontium, barium and tellurium deposited on grassland.

This work is aimed at quantifying foliar transfer of cesium, strontium, barium and tellurium under the influence of rainfall characteristics (intensity, frequency and time elapsed between contamination and first rainfall). Grassland boxes were contaminated by dry deposition of multi-element aerosols of (137)Cs, (85)Sr, (133)Ba and (123m)Te. They were grown in a greenhouse under controlled conditions. The treatments consisted of mowing and applying rainfalls (8 and 30 mmh(-1)) at different times after the contamination. At a leaf area index of 5.9+/-1.9, interception of the aerosols was similar for the 4 radionuclides (83.8+/-5.9%). Dew produced significant radionuclide accumulation in the base of the vegetation and transfer to the soil. For moderate intensity, an early (2 days after contamination) first rainfall was as efficient, in terms of leaf wash-off, as a longer rainfall occurring later (6 days after contamination). For early rainfalls, eliminated activities were comparable because the influence of rain intensity was compensated by rain duration. However, for late rainfalls, wash-off efficiency increased with rainfall intensity. Total transfer factors (TTF) were determined on whole grass immediately after 4 rainfalls and at harvest. After 4 medium intensity rainfalls, rain frequency did not influence total transfer factors (TTF) of strontium, barium and tellurium (about 0.2, 0.3 and 0.35 Bq kg(fresh weight)(-1) by Bq m(-2), respectively). Cesium TTF value was lower in the case of a weekly rain (0.1 against 0.2 Bq kg(fresh weight)(-1) by Bqm(-2)). TTF values were similar for twice-a-week rainfalls, whatever their intensity. They were higher for weekly rains of high intensity (between 0.3 and 0.75 Bq kg(fresh weight)(-1) by Bqm(-2) against 0.1-0.35 Bq kg(fresh weight)(-1) by Bq m(-2), depending on the radionuclides). TTF values attested that wash-off was more efficient when rainfalls lasted longer. Field loss on the top of the leaves was well described by an offset exponential model. The half-lives varied with rainfall characteristics from 4 days for cesium, strontium and barium to 20 days for tellurium. The offset value varied between 0% for tellurium (high intensity rainfalls) and 14% for cesium (medium intensity rainfalls).

Aerosols↗
PubMed2005

Retention and translocation of foliar applied 239,240Pu and 241Am, as compared to 137Cs and 85Sr, into bean plants (Phaseolus vulgaris).

Foliar transfer of 241Am, 239,240Pu, 137Cs and 85Sr was evaluated after contamination of bean plants (Phaseolus vulgaris) at the flowering development stage, by soaking their first two trifoliate leaves into contaminated solutions. Initial retentions of 241Am (27%) and 239,240Pu (37%) were higher than those of 137Cs and 85Sr (10-15%). Mean fraction of retained activity redistributed among bean organs was higher for 137Cs (20.3%) than for 239,240Pu (2.2%), 241Am (1%) or 85Sr (0.1%). Mean leaf-to-pod translocation factors (Bq kg(-1) dry weight pod/Bq kg(-1) dry weight contaminated leaves) were 5.0 x 10(-4) for 241Am, 2.7 x 10(-6) for 239,240Pu, 5.4 x 10(-2) for 137Cs and 3.6 x 10(-4) for 85Sr. Caesium was mainly recovered in pods (12.8%). Americium and strontium were uniformly redistributed among leaves, stems and pods. Plutonium showed preferential redistribution in oldest bean organs, leaves and stems, and very little redistribution in forming pods. Results for americium and plutonium were compared to those of strontium and caesium to evaluate the consistency of the attribution of behaviour of strontium to transuranium elements towards foliar transfer, based on translocation factors, as stated in two radioecological models, ECOSYS-87 and ASTRAL.

Americium↗
PubMed2005

Myocardial infarction and arterial thrombosis in severe (homozygous) FXII deficiency: no apparent causative relation.

Twenty-one patients (12 female and 9 male) with severe (homozygous) factor XII (FXII) deficiency and 58 (32 female and 26 male) with heterozygous FXII deficiency were observed for an average 16.2 years. No patient with homozygous FXII deficiency experienced myocardial infarction or any other arterial thrombosis. The same was true for heterozygotes. The cases of FXII deficiency and arterial thrombosis reported in the literature were evaluated. In every instance, associated risk factors were present that could justify the arterial thrombosis. Dyslipidemia, hypertension, smoking, and diabetes mellitus were the most frequent findings. The examination of the few papers that dealt with the prevalence of arterial thrombosis in patients with severe FXII deficiency showed that only 1 patient of 61 experienced myocardial infarction. In conclusion, it seems that the role of FXII deficiency in the pathogenesis of arterial thrombosis is minor.

Adolescent↗
PubMed2004

Cardiopulmonary exercise testing and exhaled nitric oxide in the assessment of patients with mitral stenosis.

AIM: In patients with mitral stenosis, symptoms do not always correlate with echocardiographic data. The aims of the study were to evaluate the role of cardiopulmonary exercise testing in the assessment of patients with mitral stenosis and to quantify nitric oxide production at rest and at the end of exercise. METHODS: We evaluated 43 patients with moderate to severe mitral stenosis with a discrepancy between echocardiographic data and symptoms. Nitric oxide output was calculated by measuring nitric oxide concentration in the exhaled air at rest and at the end of exercise test. RESULTS: Patients were divided in 2 groups: group 1 with a functional capacity <75% at cardiopulmonary exercise test (VO2max in % of the predicted one) and group 2 with functional capacity >75%. Transvalvular gradient and pulmonary artery pressure were significantly higher in group 1 than in group 2 (respectively 9.07 +/- 2.11 mmHg vs 6.01 +/- 1.08 mmHg, p<0.001 and 42.8 +/- 7.2 mmHg vs 33.1 +/- 4.7 mmHg, p<0.001). Patients of group 1 had a lower nitric oxide output at the end of exercise compared to group 2 (231.4 +/- 96.6 nl/min vs 326.3 +/- 74.0 ml/min, p=0.01) and to normal subjects (511.15 +/- 180.1 nl/min, p<0.001). CONCLUSION: Cardiopulmonary exercise testing provides objective non invasive information in the evaluation of patients with discrepancy between symptoms and echocardiographic data. Different levels of nitric oxide output during exercise suggest the role of nitric oxide in regulating pulmonary vascular tone.

Adult↗
PubMed2004

Contrast enhanced imaging of left internal mammary artery after vasodilation improves the evaluation of the bypass graft.

AIM: The aim of the study is to evaluate patency and flow reserve by echocardiography in arterial grafts using the left internal mammary artery (LIMA) to the left anterior descending coronary artery (DA). The main limitations in performing this study routinely are the weakness of the Doppler signal and the exact chest localization of the graft. The purposes of the study were: to verify the feasibility of the echo color Doppler method on LIMA; to verify which between the parasternal or supralavicular view is the better approach to obtain a clear signal; to verify the increase of systolic and diastolic flow velocity of LIMA in basal conditions and after infusion of dipyridamole, and if the visualization of the Doppler signal improves after contrast infusion. METHODS: Twenty patients (all males, mean age 63+/-7.8 years) with previous coronary artery bypass in the last 10 years, and without any significant stenosis in the left mammary artery graft as proved by a recent coronary angiogram (within 6 months), were selected for our study. LIMA was evaluated by two echocardiographic approaches. Patients were studied at rest and after pharmacological infusion of dipyridamole using the protocol of 0.56 mg/kg in 4 minutes. Contrast enhancement was infused in order to improve the Doppler signal using Levovist contrast agent at rest and after vasodilatation. Diastolic and systolic peak flow velocities, their ratio and the diastolic and total velocity time integrals were evaluated. RESULTS: The results showed that using the supraclavicular approach we obtained the visualization of the graft at rest in all patients (100%) and using the parasternal approach in 19 out of 20 (95%) even without contrast injection. At rest, the diastolic and systolic peak flow velocities were 0.417+/-0.133 m/s and 0.368+/-0.1291 m/s; their ratio (diastolic/systolic) was 0.882+/-0.7362. The overall and diastolic velocity time integrals were 0.1571+/-0.0645 m and 0.2232+/- 0.0701 m. After dipyridamole infusion we observed in all patients an increase in diastolic and systolic peak flow velocities as expected by 0.582+/-0.342 m/s (p<0.005) and 0.73+/-0.427 m/s (p<0.005). Contrast injection at rest and after peak dipyridamole infusion showed a better and clearer Doppler signal of the graft allowing an easier evaluation of the velocity curves in all patients. In fact using the association dipyridamole-Levovist the velocity ratio and the total and diastolic velocity time integral values were 1.268+/-0.368 (p<0.05), 0.3492+/-0.131 m (p<0.05) and 0.2309+/-0.153 m (p<0.05). CONCLUSION: In conclusion, this new echo-color-Doppler approach seems to be valid for the evaluation of the patency rate and flow reserve of the internal mammary artery graft, and helps to better select patients who really need angiography.

Aged↗
PubMed2004

When should asymptomatic patients with combined severe aortic stenosis and aortic insufficiency undergo valve replacement? A clinical case.

Indications to prosthetic aortic valve implantation in patients with aortic stenosis or aortic regurgitation or both stenotic or regurgitant aortic valve, who present without symptoms, are controversial. We present the case of an asymptomatic patient with combined severe aortic stenosis and an equally important insufficiency, undergoing surgery for valve substitution with a bileaflet prosthesis. After surgery he was treated with warfarin according to the doses recommended and underwent follow-up with clinical and echocardiographic exams. Eight months after intervention the patient had an embolic stroke with aphasia and right hemiplegia, despite the therapeutic level of INR. At present, even though he has partly recovered motor function, he reports a noteworthy decline in life quality, because of the persistent speech difficulties. We use this case as the starting point for a discussion of the chance of referring patients affected by aortic valvulopathy to valve substitution, in the absence of symptoms.

Anticoagulants↗
PubMed2003

Effect on dyspnoea and hypoxaemia of inhaled N(G)-nitro-L-arginine methyl ester in hepatopulmonary syndrome.

Hepatopulmonary syndrome--a complication of chronic liver disease-is characterised by hypoxaemia, which results from widespread intrapulmonary vascular dilatations. Amplified production of pulmonary nitric oxide is thought to be important in development of this disorder in patients with liver cirrhosis. Here, we report a 64-year-old man with hepatopulmonary syndrome associated with hepatitis-C-virus-related cirrhosis. We gave the patient nebulised N(G)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO synthesis, which enhanced oxygenation (arterial oxygen pressure increased from 6.98 to 9.45 kPa). After L-NAME, the distance the patient could walk in 6 min rose by 92 m. Administration of L-NAME by aerosol might offer a new approach to treatment of hepatopulmonary syndrome.

Administration, Inhalation↗
PubMed2002

Transoesophageal echocardiography in patients without arterial and major cardiac sources of embolism: difference between stroke subtypes.

We studied the records of 175 consecutive patients referred to our neurologic ward between January 1994 and February 2000 with a diagnosis of ischaemic cerebrovascular disease (ICVD) (stroke or transient ischaemic attack - TIA) who underwent transoesophageal echocardiography (TEE). We excluded patients with large vessel disease, high-risk embolic cardiopathies and other rare causes of stroke. According to clinical and neuroimaging findings, patients were divided into two groups. The lacunar (LAC) group (69/175 (39.4%)) and the nonlacunar (N-LAC) one (106/175 (60.6%)). The control population consisted of 78 consecutive patients, referred to the echocardiography laboratory for TEE without history of ICVD and known heart disorders. Patent foramen ovale (PFO) frequency was significantly higher in case patients than in control subjects (55/175 (31.4%) vs. 13/78 (16.6%); p = 0.02). Among case patients, PFO was more prevalent in the N-LAC group than in the LAC one (43/106 (40.6%) vs. 12/69 (17.4%); p = 0.0005). A large degree of shunt occurred in 53.5% of N-LAC patients and in 16.7% of LAC ones (p = 0.04). Atrial septal aneurysm (ASA) was detected in 12% of case patients and 1.3% of control subjects (p = 0.003) and was more frequent in the N-LAC group than in the LAC one (16 vs. 5.8%; p = 0.05). Mitral prolapse (MP) was present in 6/175 (3.4%) ICVD patients (vs. 1/78 among controls) in most cases associated with myxomatous valve redundancy. Aortic arch atheromas (AA) were detected in 12% of ICVD patients and in 10.2% of controls. The frequency was 9.4% in N-LAC and 15.9 in LAC. No complicated AA (plaque thickness >4 mm, ulcerated atheroma, superimposed thrombus) were detected. After multivariate analysis, PFO (OR = 3.8; 95% CI = 2.7-7.9) and ASA (OR = 8.01; 95% CI = 3.0-16.1) appeared to be independent predictors of ICVD. PFO (OR = 2.24; 95% CI = 1.24-4.92) was also independently associated with N-LAC stroke subtype and its importance was even higher in younger patients. Our study provides further evidence that TEE is a helpful diagnostic tool in stroke patients without arterial and major cardiac sources of embolism. However, its utility differs according to type and localization of the ischaemic lesion being more relevant in patient with N-LAC infarctions.

Adult↗
PubMed2002

[Evaluation and management of patients with mitral valve stenosis].

A review of the guidelines of the American College of Cardiology and the American Heart Association for the management of patients with valvular heart disease, published in 1998, is presented. The therapeutical advances introduced during the past decade, percutaneous mitral balloon valvotomy and surgical ablation of atrial fibrillation, have modified the therapeutical approach to patients with mitral stenosis. In this article some controversial aspects are examined with a review of the recent literature. The definition of "valve morphology favorable for percutaneous balloon valvotomy", which is based on echocardiographic examination, is still debatable. Different echocardiographic scores published until now are reported. Some patients, who have no or mild symptoms, develop irreversible pulmonary hypertension: in order to avoid this complication early interventional procedure is suggested, but only in those patients at low post-procedural risk. In symptomatic patients, NYHA class II/III, with atrial fibrillation it is possible to consider a conservative surgical approach combined to crioablation of atrial fibrillation. The possibility of maintaining sinus rhythm and avoiding anticoagulation leads to a revaluation of surgical repair as option to valve replacement and percutaneous mitral balloon valvotomy.

Atrial Fibrillation↗
PubMed2001

A synaptic mechanism underlying the behavioral abnormalities induced by manganese intoxication.

In the present study we have characterized a rat model of manganese (Mn) intoxication leading to behavioral disinhibition in the absence of major motor alterations. These behavioral changes were associated with significantly increased brain Mn levels but were uncoupled to anatomical lesions of the striatum or to morphological and cytochemical changes of the nigrostriatal dopaminergic pathway. The analysis of this model at cellular level showed an enhanced dopaminergic inhibitory control of the corticostriatal excitatory transmission via presynaptic D2-like dopamine (DA) receptors in slices obtained from Mn-treated rats. Conversely, the use of agonists acting on presynaptic purinergic, muscarinic, and glutamatergic metabotropic receptors revealed a normal sensitivity. Moreover, membrane responses recorded from single dopaminergic neurons following activation of D2 DA autoreceptors were also unchanged following Mn intoxication. Thus, our findings indicate a selective involvement of the D2-like DA receptors located on glutamatergic corticostriatal terminals in this pathological condition and suggest that the behavioral symptoms described in the "early" clinical phase of manganism may be caused by an abnormal dopaminergic inhibitory control on corticostriatal inputs. The identification of the synaptic mechanism underlying the "early" phase of Mn intoxication might have a critical importance to understand the causes of the progression of this pathological condition towards an "established" phase characterized by motor abnormalities and anatomical lesions of the basal ganglia.

Animals↗
PubMed2001

[Surgical treatment of atrial thrombosis. A transesophageal echocardiogram study].

Transesophageal echocardiogram is the procedure of choice in the evaluation of masses located in the cardiac chambers. In this paper three cases of atrial thrombosis are presented: a) a free floating ball thrombus in the left atrium in a patient with moderate mitral stenosis; b) three thrombotic masses adherent to a central venous catheter; c) three thrombotic masses attached to Chiari s network in a patient operated for an ostium secundum atrial septal defect one year before. In all cases transesophageal echocardiogram has played a key role in the diagnosis. Medical therapy has been inadequate and so surgical removal has been performed. Unsuccessful medical therapy, a new episode of thrombosis, intracardiac permanent catheter infections and high risk of systemic and pulmonary embolism are indications for thrombectomy.

Aged↗