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Biomedical subjects

F Maisano

Publications and source records attributed to F Maisano.

At least 19 recordsLinked to original sources
PubMed2001

Surgical and percutaneous myocardial angiogenesis induction. Part II--neoangiogenesis.

Coronary artery bypass surgery and angioplasty provide symptomatic relief in patients with ischemic heart disease, but despite advancement in technique and devices, these methods are not applicable to a subset of patients with angina refractory to medical treatment. Bypass surgery might not be feasible because of lack of suitable conduits, diffuse coronary disease or poor distal run-off, and coronary angioplasty is sometimes not applicable due to chronic total occlusion, diffuse disease or extreme tortuosity. We have previously reviewed the available experience with laser-induced direct myocardial revascularization, one of the new potential treatment modalities for this patient subset. One of the potential mechanisms of action for laser treatment is the induction of neoangiogenesis. In the second part of our article we review the available experience with the induction of myocardial angiogenesis using different growth factors or the genes encoding for them.

Coronary Disease↗
PubMed2000

Enoximone echocardiography for predicting recovery of left ventricular dysfunction after revascularization : a novel test for detecting myocardial viability.

BACKGROUND: The possibility that enoximone, a nonglycoside, noncatechol, positive inotropic agent, in combination with 2-dimensional echocardiography may predict recovery of myocardial dysfunction after revascularization has not been yet evaluated. METHODS AND RESULTS: Forty-five patients with chronic coronary artery disease and left ventricular dysfunction underwent dobutamine (DE, 5 to 10 microg. kg(-1). min(-1)) and enoximone (EE, 1.5 mg/kg, over 10 minutes) echocardiography. Myocardial wall motion was scored from 1 (normal) to 4 (dyskinesia): an asynergic segment was considered to have contractile enhancement when the score decreased by >/=1 grade. Of 478 asynergic segments, 216 (45%) exhibited functional recovery after revascularization. Dobutamine- and enoximone-induced contractile enhancement was observed in 41% and 46% of segments, respectively. Compared with DE, EE had higher sensitivity (88% versus 79%, P<0.01) and negative predictive value (90% versus 84%, P<0.05) in predicting functional recovery. The specificity (89% versus 90%) and positive predictive value (87% for both EE and DE) were similar. Concordant interpretation of EE and DE findings was found in 85% (406 of 478) of affected segments. Prerevascularization coronary angiography showed that stenosis severity of vessels supplying areas which only improved with enoximone was significantly greater (89.9%) than that of vessels (77.7%) supplying areas that responded to both agents (P<0.02). Both dobutamine and enoximone increased heart rate (16% and 10%, respectively), whereas enoximone did not cause changes in systolic blood pressure that increased by 14% with dobutamine. CONCLUSIONS: Enoximone echocardiography provides a novel and reliable approach for the prediction of functional recovery after revascularization. Compared with dobutamine echocardiography, the test yields higher sensitivity and induces lesser hemodynamic alterations.

Adult↗
PubMed2000

The double-orifice technique as a standardized approach to treat mitral regurgitation due to severe myxomatous disease: surgical technique.

OBJECTIVES: Mitral-valve repair in Barlow's disease is challenging; conventional techniques are difficult to perform, and there is a high risk of a postoperative suboptimal result. Double-orifice repair has been applied in a standardized approach to treat patients with severe mitral regurgitation and bileaflet prolapse due to Barlow's disease. METHODS: Since 1993, 82 patients with severe mitral regurgitation due to Barlow's disease underwent correction applying the edge-to-edge concept. They were submitted to double-orifice repair in a standardized fashion, suturing the middle portions of both leaflets. RESULTS: There were no hospital deaths. The repair was unsatisfactory in one patient who underwent valve replacement soon after the repair. The mean postoperative valve area was 3.7+/-0.79 cm(2) against a mean preoperative value of 9.2+/-2.1 cm(2). No or mild regurgitation was found in all but three patients who showed moderate residual regurgitation. There were no late deaths. Freedom from reoperation was 86+/-14% at 5 years. At the latest follow-up, all patient but one were New York Heart Association (NYHA) functional class I, and echo-Doppler assessment of valve reconstruction showed stable valve function in all patients. CONCLUSIONS: The double-orifice repair can be used as a standardized approach to treat valve regurgitation due to Barlow disease with low risk and good early and mid-term results.

Adult↗
PubMed2000

Ventricular motion during the ejection phase: a computational analysis.

In the present paper, the study of the ventricular motion during systole was addressed by means of a computational model of ventricular ejection. In particular, the implications of ventricular motion on blood acceleration and velocity measurements at the valvular plane (VP) were evaluated. An algorithm was developed to assess the force exchange between the ventricle and the surrounding tissue, i.e., the inflow and outflow vessels of the heart. The algorithm, based on the momentum equation for a transitory flowing system, was used in a fluid-structure model of the ventricle that includes the contractile behavior of the fibers and the viscous and inertial forces of the intraventricular fluid. The model calculates the ventricular center of mass motion, the VP motion, and intraventricular pressure gradients. Results indicate that the motion of the ventricle affects the noninvasive estimation of the transvalvular pressure gradient using Doppler ultrasound. The VP motion can lead to an underestimation equal to 12.4 +/- 6.6%.

Algorithms↗
PubMed2000

Surgical and percutaneous myocardial angiogenesis induction. Part I--laser revascularization.

Coronary artery bypass surgery and angioplasty provide symptomatic relief in patients with ischemic heart disease, but despite advancement in technique and devices, these methods are not applicable in a subset of patients with angina refractory to medical treatment. Bypass surgery may not be feasible because of lack of suitable conduits, diffuse coronary artery disease or poor distal run-off, and coronary angioplasty is sometimes not applicable due to chronic total occlusion, diffuse disease or extreme tortuosity. Transmyocardial laser revascularization and the stimulation of neoangiogenesis by a variety of growth factors have recently emerged as a new tool in the management of these patients. In the first part of this article, we review laser-induced direct myocardial revascularization, its indications, potential risks, and published clinical trials. The induction of neoangiogenesis using different growth factors or the genes encoding for them will be the subject of the second part of our review.

Angina Pectoris↗
PubMed1999

The hemodynamic effects of double-orifice valve repair for mitral regurgitation: a 3D computational model.

OBJECTIVES: A 3D computational model has been implemented for the evaluation of the hemodynamics of the double orifice repair. Critical issues for surgical decision making and echo-Doppler evaluation of the results of the procedure are investigated. METHODS: A parametric 3D computational model of the double-orifice mitral valve based on the finite elements model has been constructed from clinical data. Nine different geometries were investigated, corresponding to three total inflow areas (1.5, 2.25 and 3 cm2) and to three orifice configurations (two equal orifices, two orifices of different areas, i.e. one twice as much the other one, and a single orifice). The simulations were performed in transit; the fluid was initially quiescent and was accelerated to the maximum flow rate with a cubic function. For each case, some characteristic values of velocity and pressure were determined: velocities were calculated downstream of each orifice, at the centre of it (Vcen1, Vcen2). The maximum velocity was also determined for each orifice (Vmax1, Vmax2). Maximum pressure drops (deltap(max)) across the valve were compared with the estimations (deltap(Bernoulli)) based on the Bernoulli formula (4 V2). RESULTS: In each simulation, no notable difference was observed between Vcen1 and Vcen2, and between Vmax1 and Vmax2, regardless of the valve configuration. Maximum velocity and deltap(max) were related to the total orifice area and were not influenced by the orifice configuration. Deltap(Bernoulli) calculated with Vmax was well correlated with the deltap(max) obtained throughout the simulations (y = 0.9126x + 0.3464, r = 0.996); on the contrary the pressure drops estimated using Vcen underestimated (y = 0.6757x + 0.3073, r = 0.999) the actual pressure drops. CONCLUSIONS: The hemodynamic behaviour of a double orifice mitral valve does not differ from that of a physiological valve of same total area: pressure drops and flow velocity across the valve are not influenced by the configuration of the valve. Echo Doppler estimation of the maximum velocities is a reliable method for the calculation of pressure gradients across the repaired valve.

Blood Flow Velocity↗
PubMed1998

The edge-to-edge technique: a simplified method to correct mitral insufficiency.

OBJECTIVE: Repair of mitral regurgitation (MR) is more demanding in case of prolapse of the anterior leaflet, posterior leaflet with calcified annulus, or prolapse of both leaflets. We evaluated a repair which consists of anchoring the free edge of the prolapsing leaflet to the corresponding free edge of the facing leaflet: the 'edge-to-edge' (E-to-E) technique. The correction results in a double orifice valve when the prolapse is in the middle portion of the leaflet and in a smaller valve orifice when the prolapse is close to a commissure. METHODS: Out of 432 patients with MR submitted to valve repair between January 1991 and September 1997, 121 (mean age 56 +/- 15.8 years) underwent E-to-E correction. The most prevalent etiology was degenerative disease (82 patients, 68%). The mechanism of MR was anterior leaflet prolapse (61 patients), posterior leaflet prolapse (24 patients), prolapse of both leaflets (28 patients) and other complex mechanisms (8 patients). In 72 patients, a double orifice was created, the paracommissural repair was done in 49 patients. RESULTS: Hospital mortality was 1.6%. Overall survival was 92 +/- 3.1% at 6 years with 95 +/- 4.8% freedom from reoperation. Mortality was unrelated to the type of repair. Mitral stenosis was never observed after the correction. At the follow-up (mean 2.2 +/- 1.5 years), all patients but 15 are class I or II. Symptoms at the follow-up are not related to residual MR. CONCLUSIONS: Midterm results of this alternative repair technique are promising, considering the high prevalence of complex anatomical lesions. The technique is simple, easily reproducible and rapidly feasible also when mitral exposure is suboptimal.

Adolescent↗
PubMed1998

[Models of preoperative risk stratification in cardiac surgery: the prediction of mortality or of survival?].

BACKGROUND: The need to assess the quality of heart surgery outcomes stimulated the development of pre-surgical risk stratification models in order to predict outcome on the basis of patient characteristics. The aim of the study was to compare the predictive accuracy of hospital mortality according to the following three models: Parsonnet (NBI Score), Higgins (CCF Score) and Roques (French Score), in a setting totally independent from the one in which the models were derived. METHODS: For each of the 516 patients undergoing heart surgery at our institution between January 1992 and December 1993, we calculated the pre-surgical risk according to the three models. Then we compared the predicted mortality against the observed mortality by means of the Shannon accuracy index, the ROC curve analysis and the overestimation histogram. RESULTS: Overall observed mortality (1.5%) was similar to the predicted mortality by the NBI Score (1.5 +/- 2.1%, p = ns), the CCF Score (1.7 +/- 2.0%, p = ns) and the French Score (1.9 +/- 2.5%, p = ns). The predictive accuracy of global mortality is very high and equal with the three models, and it is very low in the 8 patients who died (NBI Score = 0.06 +/- 0.06; CCF Score = 0.125 +/- 0.067; French Score = 0.102 +/- 0.07, p = ns). The area under the ROC curve is identical in the 3 models. CONCLUSIONS: The predicted mortality obtained by the three models is not significantly different from the observed mortality and therefore, the global accuracy is similar and very high, while it is very low for patients who will die. The models for pre-surgical risk stratification are useful for comparing the results among different institutions or different surgeons, or for monitoring the results over time in the same institution, but they cannot be used to accurately predict the individual risk of hospital mortality.

Aged↗
PubMed1997

[Repair in rheumatic mitral valve insufficiency].

OBJECTIVES: Emerging evidence indicates that etiology plays an essential role in the results of mitral valve repair. In this study, we examined the long-term performance of this procedure in 61 consecutive patients with pure rheumatic mitral insufficiency. PATIENTS: Patient ages ranged from 4 to 74 years (mean: 51.7 +/- 16). Preoperatively, 94% of the patients were in NYHA class II or III. RESULTS: There was no hospital mortality. According to actuarial methods 94.1% of the patients were alive 7 years postoperatively and 83.3% were reoperation free. Freedom from reoperation was significantly higher in patients who received a prosthetic ring than in those who had other types of annuloplasty (96.7% vs 59.3%; p = 0.001). As opposed to the literature, in our series there was no relationship between valve failure and age at the time of reoperation. There were only two cases of thromboembolism and one of infective endocarditis. CONCLUSIONS: This study confirms that mitral valve reconstruction in rheumatic valve insufficiency can yield satisfactory long-term clinical results, although they are less than optimum compared with those obtained in patients with degenerative disease. Favourable results depend on routine use of a prosthetic ring as well as adequate patient selection. Attention should be focused on improved detection and suppression of rheumatic activity at the time of operation.

Actuarial Analysis↗
PubMed1996

Valve repair for traumatic tricuspid regurgitation.

OBJECTIVE: The review of six cases of valve repair for traumatic tricuspid regurgitation in our institution and 74 in the literature in order to assess effective methods of treating this lesion. METHODS: Tricuspid valve regurgitation is a rare complication of blunt chest trauma. Optimal treatment for this condition is still controversial ranging from long-term medical therapy to early surgical correction. We followed the cases of six consecutive patients with post-traumatic tricuspid incompetence who were successfully treated with reparative techniques. All patients were male and their ages ranged from 18 years to 42 years. Valve regurgitation was always secondary to blunt chest trauma due to motor vehicle accident. The mechanism of valve insufficiency was invariably anterior leaflet prolapse due to chordal or papillary muscle rupture associated with annular dilatation. Surgical procedures included Carpentier ring implant (5 patients), Bex posterior annuloplasty (1 patient), implant of artificial chordae (4 patients), papillary muscle reinsertion (2 patients), commissuroplasty (1 patient) and "artificial double orifice" technique (1 patient). RESULTS: Tricuspid insufficiency improved in all patients after the correction. No complications were recorded and all patients were asymptomatic at the follow-up. CONCLUSIONS: Since post-traumatic tricuspid regurgitation is effectively correctable with reparative techniques, early operation is recommended to relieve symptoms and to prevent right ventricular dysfunction.

Adolescent↗
PubMed1995

[Combined valve repair for mitral-aortic insufficiency].

Reconstructive surgery is considered the best treatment of mitral insufficiency. Aortic valvuloplasty has been used only rarely in the past for the treatment of aortic insufficiency. Between October 1994 and November 1994, two patients admitted at our institution with the diagnosis of mitral and aortic insufficiency have been successfully submitted to combined valvuloplasty. Although long term results of aortic reconstruction are unavailable, short-term and middle-term results are satisfactory and warrant conservative surgery in selected cases. Aortic repair is an attractive option especially in those patients with combined aortic insufficiency and mitral disease suitable for valvuloplasty.

Aortic Valve Insufficiency↗
PubMed1993

Dynamic cardiomyoplasty as an effective therapy for dilated cardiomyopathy.

Nine male patients with dilated cardiomyopathy unresponsive to maximal medical therapy were submitted to dynamic cardiomyoplasty according to the technique described by Carpentier and Chachques, and preliminary postoperative results are reported. Seven patients were in New York Heart Association (NYHA) Class III and two were in intermittent Class IV. The mean age was 56 years (range 51 to 61 years). Preoperative ejection fraction (EF) by multiple gated acquisition ranged from 14% to 28% (mean 20.7%). No additional surgery was performed. Transesophageal echocardiographic monitoring was used during surgery to guide the wrapping procedure. There was no operative mortality. There was one early death (1 month). One late death (sudden death) occurred 7 months after surgery despite significant clinical improvement. Follow-up ranges from 2 to 16 months. Six patients were submitted to hemodynamic evaluation from 4 to 6 months after surgery by transthoracic and transesophageal echo-Doppler assessment. Effective latissimus dorsi support was clearly documented in all patients by comparing postoperative basal hemodynamic values (Cardiomyostimulator [Medtronic, Inc.] switched off) and data obtained during assisted beats (EF increased from 19.4% +/- 8.6% to 32.6% +/- 13.8%, p = 0.043; and stroke volume increased from 51.6 +/- 20.6 mL to 63.0 +/- 22.0 mL, p = 0.014). All patients who completed the latissimus dorsi training protocol were in NYHA Class I or II. A significant reduction in postoperative medical therapy was achieved in all patients. Our preliminary results confirm that the cardiomyoplasty procedure is to be considered a safe and valuable mean for treating selected patients with dilated cardiomyopathy refractory to maximal pharmacological treatment.

Assisted Circulation↗
PubMed1991

A new human growth hormone production process using a recombinant Bacillus subtilis strain.

We constructed a series of hybrid plasmids which directed the synthesis of different human growth hormone (hGH) precursor sequences in Bacillus subtilis. In addition to the 191 amino acids of the hormone, the precursors had in common an amino-terminal extension characterized by the presence of a methionine at position 1 and of the tetrapeptide Ile-Glu-Gly-Arg preceding the first residue (Phe) of hGH. The sequence between the methionine and the tetrapeptide was specific for each precursor and, because of the presence of charged residues, conferred particular properties to the molecules. Long homopolymeric tail-containing precursors such as MRRRRRRIILM-IEGR appeared insoluble whereas shorter sequences of the type MRR-IEGR and MEELM-IEGR augmented the solubility of the precursors with respect to Met-hGH. The soluble precursors could be easily purified from the bulk proteins taking advantage of the charged residues present on the N-terminal tail. After purification, the natural hGH was obtained by treating the precursors with the protease Factor Xa which cleaves after the arginine residue of the tetrapeptide IEGR. A protocol for the production and purification of authentic hGH from a strain expressing one of these soluble precursors is reported.

Amino Acid Sequence↗
PubMed1985

Thiophilic adsorption--a new method for protein fractionation.

Divinylsulphone-activated agarose to which mercaptoethanol is coupled showed very selective group adsorption of human serum proteins, in particular the immunoglobulins. The adsorption increases markedly in the presence of high concentrations of neutral water-structure forming salts and is distinct from adsorptions based on hydrophobic interaction. A characteristic feature of this new type of adsorbent is the structure of the groups attached to the polymer, P, i.e., R-S-CH2-CH2-SO2-CH2-CH2-O-P, where R is a small aliphatic residue. Our results indicate that the thioether sulphur and the adjacent sulphone group act cooperatively and are apparently necessary to maintain the distinct behaviour of such absorbents.

Adsorption↗
PubMed1985

Synthesis of new hydrophobic adsorbents based on homologous series of uncharged alkyl sulphide agarose derivatives.

A homologous series of uncharged thioalkyl derivatives of agarose were prepared by a simplified synthetic route and their adsorption behaviour towards human serum proteins was evaluated and compared with that of a commercially available alkyl ether derivative of agarose. The influence of the spacer arm length on the adsorption efficiency was also investigated. The degree of substitution of the derivatives can be estimated conveniently by sulphur analysis. The four different types of thiolkyl derivatives (C6, C8, C12 and C14) investigated here behave in all respects like hydrophobic adsorbents. The coupling yield obtained is high (75% or more) and is better than that obtained by alternative synthetic routes reported so far. The adsorption capacity towards serum proteins of the various derivatives increases with increasing alkyl chain length and degree of substitution. Desorption is achieved by a progressive decrease in the polarity of the eluent and the recovery of the applied material is in the range 80-90%. The role played by the thioether as a possible modulator of the observed hydrophobic adsorption is discussed. For the group separation of serum proteins the optimum adsorbent, as regards capacity combined with ease of elution of adsorbed material, should be substituted with chains of six or eight carbon atoms and have a ligand concentration in the range 80-120 mumole g-1 dry gel.

Adsorption↗
PubMedDate not supplied

Coupling of DTPA to proteins: a critical analysis of the cyclic dianhydride method in the case of insulin modification.

The reaction between the cyclic dianhydride of diethylenetriaminepentaacetic acid (DTPA), a bifunctional reagent, and proteins under various conditions was studied using porcine insulin as a model protein. The reaction was compared with that between citraconic anhydride, a monofunctional reagent, and insulin. Products were characterized chromatographically and electrophoretically before and after deesterification by hydroxylamine. A DTPA-conjugated product was further characterized by proteolytic fragmentation. The reaction with citraconic anhydride yielded the expected number of products exclusively acylated on amino groups. In contrast, the reaction with the cyclic dianhydride of DTPA under all conditions examined yielded a much higher number of products than expected. Among the products formed were O-acylated ones and products of intermolecular cross-linking. It is concluded that the use of the cyclic dianhydride of DTPA does not allow the reliable preparation of proteins or other macromolecules conjugated with a high number of DTPA molecules in which each molecule of DTPA is linked to one amino group of the macromolecule through a single amide bond.

Anhydrides↗