Biomedical subjects

Francesco Musumeci

Publications and source records attributed to Francesco Musumeci.

11 recordsLinked to original sources

PubMed2006

Evaluation of 17-mm St. Jude Medical Regent prosthetic aortic heart valves by rest and dobutamine stress echocardiography.

BACKGROUND: The prosthesis used for aortic valve replacement in patients with small aortic root can be too small in relation to body size, thus showing high transvalvular gradients at rest and/or under stress conditions. This study was carried out to evaluate rest and Dobutamine stress echocardiography (DSE) hemodynamic response of 17-mm St. Jude Medical Regent (SJMR-17 mm) in relatively aged patients at mean 24 months follow-up. METHODS AND RESULTS: The study population consisted of 19 patients (2 men, 17 women, mean age 69.2 +/- 7.3 years). All patients underwent rest Doppler echocardiography before and after surgery and basal and DSE at follow up (infused at rate of 5 microg/Kg/min and increased by 5 microg/Kg/min at 5 min intervals up to 40 microg/Kg/min). The following parameters were evaluated at rest and/or under DSE: heart rate (HR), ejection fraction (EF), cardiac output (CO), peak and mean velocity and pressure gradients (MxV, MnV, MxPG, MnPG), effective orifice area (EOA), indexed EOA (EOAi), left ventricular mass (LVM), indexed LVM (LVMi), Velocity Time Integral at left ventricular outflow tract (VTI LVOT) and transvalvular (Aortic VTI), Doppler velocity index (DVI). At rest MxPG and MnPG were 29.2 +/- 7.1 and 16.6 +/- 5.8 mmHg, respectively; EOA and EOAi resulted 1.14 +/- 0.3 cm(2) and 0.76 +/- 0.2 cm(2)/m(2); DVI was normal (0.50 +/- 0.1). At follow-up LVM and LVMi decreased significantly from pre-operative value of 258 +/- 43 g and 157.4 +/- 27.7 g/m(2) to 191 +/- 23.8 g and 114.5 +/- 10.6 g/m(2), respectively. DSE increased significantly HR, CO, EF, MxGP (up to 83.4 +/- 2 1.9 mmHg), MnPG (up to 43.2 +/- 12.7 mmHg). EOA, EOAi, DVI increased insignificantly (from baseline up to 1.2 +/- 0.4 cm(2), 0.75 +/- 0.3 cm(2)/m(2) and 0.48 +/- 0.1 respectively). Two patients developed significant intraventricular gradients. CONCLUSION: These data show that SJMR 17-mm prostheses can be safely implanted in aortic position in relatively aged patients, offering a satisfactory hemodynamic performance at rest and under DSE, with full utilization of its available orifice, suggesting that a possible mild prosthesis-patient mismatch is not an issue of clinical relevance when this small prosthesis is used. Rest and Dobutamine stress echocardiography is a useful and effective means for evaluating prosthesis hemodynamics and for monitoring the expected LVH regression.

Aged↗

PubMed2005

Spectral analysis of laser-induced ultraweak delayed luminescence in cultured normal and tumor human cells: temperature dependence.

The emission spectrum of ultraviolet A laser induced ultraweak delayed luminescence in cell cultures of mammalian cells depended on the temperature during irradiation and photonic measurements. A new method using a sophisticated photomultiplier system was developed in order to find differences between normal and tumor cells. The maximal peak of the emitted light for cultures measured at low temperature of 10 degrees C was near 510 nm in the green visible region while following irradiation at 32 degrees C this maximum was shifted to yellow-orange at 570 nm both in normal and melanoma cells. Overall, this ultraweak photonic model of cultured cells provides to be a new and powerful non-invasive tool for developing new strategies in skin cancer detection.

Adult↗

PubMed2005

Transaxillary aortic endoclamping for ascending aortic pseudoaneurysm and dissected descending aorta.

Patients presenting with pseudoaneurysm of the aortic root close to the sternum, severe aortic regurgitation, and chronic dissection of the descending aorta represent a formidable surgical challenge. Closed chest circulatory arrest in this setting carries a high risk of myocardial or brain damage. We propose a modification of the port-access technique that allows control and access of the pseudoaneurysm, avoiding the need for closed chest circulatory arrest. Our strategy is based on transaxillary endoclamping of the ascending aorta and combines the advantages of antegrade aortic flow with the possibility of stopping the heart and venting the left ventricle before sternotomy.

Aortic Dissection↗

PubMed2005

Endovascular aortic clamping for pseudoaneurysms of the aortic root with aortic regurgitation.

BACKGROUND: We propose a safer strategy for surgical treatment of retro-sternal pseudoaneurysms of the aortic root with severe aortic regurgitation. The objective was to allow safer re-entry in a quite and bloodless field eliminating the risk of ventricular distension and avoiding deep hypothermia. METHODS: In 6 patients presenting with postsurgical aortic root pseudoaneurysms in close proximity to the sternum associated with aortic regurgitation, we used the following techniques: femorofemoral cardiopulmonary bypass; transfemoral aortic endoclamping; percutaneous retrograde cardioplegia administration before sternotomy in patients with normal descending aorta; femoroaxillary cardiopulmonary bypass; transaxillary aortic endoclamping; percutaneous retrograde cardioplegia administration before sternotomy in patients with concomitant disease of the descending aorta. RESULTS: All patients survived the operation and were discharged home. Arterial cannulation and endoclamp insertion were uneventful. Reentry was uncomplicated. Deep hypothermia was avoided in all cases. No occurrences of even minor neurologic problems were observed. None of these patients experienced a postoperative low cardiac output syndrome. Postoperative course was complicated in 1 patient with re-entry for bleeding; acute renal insufficiency requiring hemofiltration in 2 patients; pneumonia in 1 patient; and soft tissues sternotomy infection in 1 patient. CONCLUSIONS: In patients presenting with a pseudoaneurysm of the aortic root attached to the sternum and concomitant aortic regurgitation it is possible, by closed chest endovascular aortic clamping, to eliminate risks of ventricular distension and to avoid deep hypothermia.

Adult↗

PubMed2005

A normogram to anticipate dimension of neo-sinuses of valsalva in valve-sparing aortic operations.

OBJECTIVE: The aim of the present study was to define a method to pre-determine the correct size of neo-sinuses of Valsalva in the reimplantation type of valve-sparing aortic operation. METHODS: The objective was achieved in three steps: (1) evaluation in the healthy population, of the normal size of sinuses of Valsalva expressed as the area surrounding fully opened aortic cusps, the so-called beyond leaflets area; (2) elaboration of a normogram by which, given a known annular diameter, it is possible to select the appropriate graft size to obtain a normal beyond leaflets area; (3) validation of the normogram by comparing, in a population of 20 patients undergoing a valve-sparing procedure, the predicted and observed beyond leaflets area. RESULTS: The following values for beyond leaflets area were observed: mean normal 320.6+/-120.6mm(2), mean predicted 355+/-63.2mm(2), mean observed 364.7+/-72.8mm(2).No significant differences were obtained for predicted versus observed values. Regression analysis showed a linear distribution with an r value of 0.95. CONCLUSIONS: We proposed a simplified approach for sizing of the neo-aortic root in the reimplantation type of valve-sparing aortic operation focussed on the size of sinuses of Valsalva. Our normogram showed to be reliable in anticipating beyond leaflets area. It can be helpful in avoiding the selection of an undersized or excessively oversized graft.

Adult↗

PubMed2004

Endothelium-dependent noradrenergic hyperresponsiveness induced by thapsigargin in human saphenous veins: role of thromboxane and calcium.

To further investigate the mechanisms which regulate sympathetic vascular tone, we studied the effects of the sarcoplasmic reticulum Ca(2+)-ATPase inhibitor, thapsigargin, on the vasoconstriction induced by transmural nerve stimulation and noradrenaline in superfused human saphenous vein rings. The contractions induced by both transmural nerve stimulation and noradrenaline were potentiated by thapsigargin in endothelium-intact, but not in endothelium-denuded vessels. This potentiation was unaffected by the non-selective endothelin ET(A/B) receptor antagonist, Ro 47-0203 (4-tert-Butyyl-N-[6-(2-hydroxy-ethoxy)-5-(2-methoxy-phenoxy)-2,2'-bipyrimidin-4yl]benzene sulfonamide), or by the nitric oxide (NO) synthase inhibitor, L-NNA (N(omega)-nitro-L-arginine), but was inhibited by the thromboxane A(2) receptor antagonist, Bay u3405 (3(R)-[[(4-flurophenyl) sulphonyl]amino-1,2,3,4-tetrahydro-9H-carbazole-9-propanoic acid]) or by the thromboxane A(2) synthase inhibitor, UK 38485 (3-(1H-imidazol-1-yl-methyl)-2-methyl-1H-indole-1-propanoic acid). Moreover, the thapsigargin-induced noradrenergic hyperresponsiveness, as well as that produced by subthreshold concentrations of the thromboxane A(2) mimetic, U 46619, were blocked by the Ca(2+) channel antagonist, verapamil. In conclusion, our results indicate that thapsigargin enhances the contractions produced by sympathetic nerve stimulation in human saphenous vein rings through the endothelial release of thromboxane A(2) that potentiates the vasoconstriction induced by the noradrenergic mediator with a verapamil-sensitive mechanism.

Analysis of Variance↗

PubMed2004

Limited thoracotomy as a second choice alternative to transvenous implant for cardiac resynchronisation therapy delivery.

AIMS: Left ventricular (LV) pacing via transvenous implantation has an overall success rate ranging from 88% to 92%. The aim of this study was to assess whether LV pacing via limited thoracotomy would be feasible and safe when used on a routine basis for those cases in which standard transvenous procedures proved to be ineffective or unsatisfactory. METHODS AND RESULTS: We enrolled 33 patients (8 females, 65+/-10 years) who experienced a transvenous implantation failure. All patients underwent a limited thoracotomy and an epicardial lead was implanted. The procedure time was 51+/-28 min. No surgical or post-operative complications occurred and optimal lateral position was achieved for all patients. In the 12 months follow-up period, 5 patients died from refractory heart failure, the remaining patients did not experience complications. At implant, the mean pacing threshold was 1.3+/-0.7 V, bi-ventricular pacing impedance was 476+/-201 Omega and R-wave amplitude was 15.0+/-6.1 mV. No significant differences were found in any of the electrical parameters between baseline and follow-up. Significant improvement was observed in functional and echocardiographic parameters. CONCLUSION: Our results suggest that a combined approach to cardiac resynchronisation therapy delivery, including a transvenous attempt followed by a back up thoracotomic procedure, could potentially guarantee the success.

Aged↗

PubMed2004

[Cardiac surgery in the elderly: patient selection criteria and results].

Selection of elderly patients for heart failure surgery is based on careful evaluation of the risk/benefit ratio. The global risk profile and the single variable impact can be easily quantified by using validated scoring systems. Both age and left ventricular dysfunction are independent determinants of mortality; nevertheless they cannot be considered absolute contraindications for surgery. Risk of mortality is related to age in a linear fashion; consequently an age cut-off value for excluding patients from surgery cannot be defined. The presence of other risk factors and the resulting global risk profile have to be considered to identify suitable patients for surgery. Elderly patients undergoing mitral valve surgery need a particularly accurate assessment since mitral procedures are associated with an increased short- and medium-term mortality; hemodynamic instability, renal failure, advanced heart failure and concomitant coronary surgery might contraindicate surgery. A significant improvement in the functional status and quality of life justifies surgical treatment of elderly patients when the predicted risk is reasonable although benefits in terms of increased survival have not been clearly confirmed yet.

Age Factors↗

PubMed2003

Nonlinear dependence of the delayed luminescence yield on the intensity of irradiation in the framework of a correlated soliton model.

We generalize the correlated soliton model in order to describe the delayed luminescence arising from biological systems after their exposition to the irradiation by relatively high dose (high intensity and/or long duration of irradiation). The quantum yield of the delayed luminescence is calculated as a function of the irradiation and is shown to depend nonlinearly on the intensity and dose of the irradiation. At relatively low intensity, the yield of luminescence increases with increasing dose, and monotonously reaches saturation. At high intensity of the irradiation, the yield of the photosystem under study is restricted from above by the concentration of photosystem units. As a result, the total yield of the delayed luminescence first increases with the dose till the maximum value that, in the general case, is less than the maximum number of available photosystem units. With further increase of the dose, the yield gradually decreases, reaching the saturation value at large dose of illumination. These results are obtained within the steady state approximation in the description of the luminescence kinetics. To check the applicability of this approximation at high levels and large time of illumination, the corrections to the steady state solution have been calculated, and shown to decrease exponentially with increase in time till the small finite constant value. The results of the theoretical model are shown to describe well the experimental data on the dose dependence of the quantum yield of the luminescence of algae Acetabularia acetabulum, for which the correlated soliton model describes well the kinetics of the delayed luminescence at low levels of irradiation.

Journal Article↗

PubMed2003

Solid state approach in biophoton research.

Main characteristics of the delayed luminescence (DL) emitted in the seconds range from biological systems is analyzed. The correlation between change in DL and cell's organization, and similarity with some characteristics of DL from solid state system suggest to connect DL in biological system to decay of collective electron states, formed during energy and charge transport along the macromolecular ordered structures which form the cell. Results of a proposed soliton model are discussed, together with some phenomenological evidence which emphasize the possibility of using DL measurements as an intrinsic probe in biophysical investigations.

Luminescent Measurements↗

PubMed1999

Diagnosis of Myocardial Abscess After Acute Myocardial Infarction by Transesophageal Echocardiography: Case Report and Short Review of Published Data.

A 56-year-old man received thrombolysis for an anterior myocardial infarction after chest pain for 18 hours. Ten days later he was readmitted with fever and hemodynamic deterioration. Transesophageal echocardiography demonstrated a thin-walled cavity at the apex of the left ventricle. At operation he was found to have a myocardial abscess, and after excision and antibiotics his subsequent clinical course was uneventful. We review the echocardiographic diagnosis and clinical features of myocardial abscess complicating acute infarction. Presumed etiologic factors in our patient included late thrombolysis, mural thrombus, and poor dental hygiene leading to septicaemia.

Journal Article↗