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Biomedical subjects

A Milano

Publications and source records attributed to A Milano.

At least 55 records · Page 3Linked to original sources
PubMed1998

mmr, a Mycobacterium tuberculosis gene conferring resistance to small cationic dyes and inhibitors.

The mmr gene, cloned from Mycobacterium tuberculosis, was shown to confer to Mycobacterium smegmatis resistance to tetraphenylphosphonium (TPP), erythromycin, ethidium bromide, acriflavine, safranin O, and pyronin Y. The gene appears to code for a protein containing four transmembrane domains. Studies of [3H]TPP intracellular accumulation strongly suggest that the resistance mediated by the Mmr protein involves active extrusion of TPP.

Amino Acid Sequence↗
PubMed1998

Ascending aorta dissection after aortic valve replacement.

BACKGROUND AND AIMS OF THE STUDY: The surgical management of patients with aortic valve disease associated with ascending aortic dilatation is a controversial issue. Structural abnormalities of the aortic wall predispose to further aortic enlargement and possibly to ascending aortic dissection (AAD). Indications to concomitant replacement of aortic valve and ascending aorta have not yet been clearly defined. METHODS: We reviewed eight consecutive patients (seven males and one female) among 2202 patients who underwent aortic valve replacement (AVR) between 1982 and 1996. These eight were subsequently reoperated on because of AAD, between November 1987 and November 1996. Indications for initial AVR were aortic regurgitation due to annular ectasia in five patients, combined aortic stenosis and regurgitation in two, and isolated aortic stenosis in one patient. RESULTS: The interval between AVR and AAD ranged from four months to 10.5 years. Five patients presented with acute AAD, and three with chronic AAD. Retrospectively, four patients showed progressive increase in ascending aortic diameter after AVR, with a mean diameter of 72+/-9 mm at reoperation. Histological examination showed cystic medial necrosis in three patients, atherosclerotic degeneration in one patient, and normal aortic wall structure in one. There was one operative death due to low cardiac output; the hospital mortality rate was 13%. There were no late deaths and no major adverse events during a mean follow up of 5+/-3 years (range: 8 months to 10 years). CONCLUSIONS: In patients with ascending aortic dilatation (> or = 55 mm diameter), AVR alone may not prevent progression of aortic root enlargement. In these patients, the ascending aorta should be concomitantly replaced. Following AVR, all patients with mildly or moderately dilated aortic root should be periodically controlled to detect signs of progression of aortic dilatation.

Acute Disease↗
PubMed1998

Enlargement of the aortic annulus with glutaraldehyde-fixed bovine pericardium during aortic valve replacement.

BACKGROUND AND AIMS OF THE STUDY: Aortic valve replacement in patients with a small aortic annulus may represent a surgical challenge. We have evaluated a simplified technique to enlarge the aortic annulus which consists of extending the aortotomy incision to divide the commissure between the left and non-coronary cusps into the interleaflet triangle without opening the left atrium. METHODS: This technique was used in 16 patients (15 women, one man; mean age 66 +/- 9 years) who underwent aortic valve replacement between August 1994 and February 1996. Aortic stenosis was the predominant valvular lesion. A mechanical prosthesis was implanted in 13 patients (81%) (21 mm in six, 23 mm in seven) while three received a bioprosthesis (21 mm in one, 23 mm in two). In all patients it was possible to insert a prosthesis at least one size larger than the original aortic annulus diameter. RESULTS: There were no operative deaths and no late deaths. Mean follow up was 20 +/- 6 months (range: 12 to 30 months). Echocardiographic controls at 12 months postoperatively showed no evidence of periprosthetic leaks or mitral regurgitation. Comparison with preoperative data showed no significant variations of mean aortic diameter at the sinus level (30.7 +/- 2.2 mm versus 31.3 +/- 2.6 mm) or at the sinotubular junction (33.6 +/- 2.7 mm versus 34.3 +/- 2.9 mm) (p = NS). Significant reduction of left ventricular mass was observed (314 +/- 57 g versus 260 +/- 45 g; p < 0.001). CONCLUSIONS: This technique is simple, reproducible and effective in allowing adequate enlargement of the aortic annulus and provides excellent clinical and hemodynamic results. Glutaraldehyde-fixed bovine pericardium used as a patch material showed no tendency to aneurysmal dilatation with progression of time at a maximum follow up of 30 months.

Aged↗
PubMed1998

Aortic valve replacement for quadricuspid aortic valve incompetence.

Quadricuspid aortic valve is an uncommon cause of aortic regurgitation. We report two patients who underwent aortic valve replacement because of severe aortic incompetence; the presence of a quadricuspid aortic valve was an accidental surgical finding. In one patient the aortic valve comprised two equal-sized larger cusps and two equal-sized smaller cusps, while in the other it comprised three cusps of similar size and a small accessory cusp between the right and non-coronary cusps. This report confirms the rarity of the disease and the fact that patients with quadricuspid aortic valves characterized by cusps of different sizes are more prone to develop progressive aortic incompetence because of unequal distribution of stresses on the valve. Therefore, such patients should undergo periodic, life-time echocardiographic assessment once this malformation is detected.

Aged↗
PubMed1997

Transmyocardial laser revascularization using a thoracoscopic approach.

Transmyocardial revascularization is a new technique aimed to improve perfusion of the ischemic myocardium by creating transmyocardial channels with a laser. This report demonstrates that transmyocardial revascularization with a holmium laser can be performed through a thoracoscopic approach.

Coronary Disease↗
PubMed1997

Post-traumatic ventricular septal defect following coronary bypass surgery.

A 60-year-old patient underwent triple coronary artery bypass grafting following an inferoseptal myocardial infarction and early onset of exertional angina. Four years later he was involved in a car accident during which he sustained an abdominal and thoracic trauma. Approximately 1 month after discharge, a ventricular septal defect was diagnosed by two-dimensional Doppler echocardiography with patency of all grafts at coronary angiography. Closure of the septal defect was successfully accomplished through a right atrial approach. Rupture of the ventricular septum following blunt chest trauma in a patient with previous myocardial revascularization has not been previously reported.

Abdominal Injuries↗
PubMed1997

Hemodynamic performance of the Edwards Prima stentless valve.

BACKGROUND AND AIM OF THE STUDY: Stentless porcine valves are considered to have a superior hemodynamic performance when compared with stented bioprostheses. In the present study we report our initial experience with the Edwards Prima stentless valve (EPSV), focusing on the hemodynamic performance of this device evaluated by means of transthoracic two-dimensional (2D) Doppler echocardiography. METHODS: Between December 1994 and August 1995, 23 patients underwent aortic valve replacement with the EPSV implanted in the subcoronary position. Evaluation of hemodynamic performance of the EPSV was assessed before discharge (one week) and at six months follow up by means of transthoracic 2D echocardiography. RESULTS: There were no operative deaths and no major postoperative complications. Hemodynamic data were available for comparison at one week and six months in 18 patients (23 mm, n = 8; 25 mm, n = 10). For 23 mm EPSV, peak gradient varied from 42.7 +/- 10.2 mmHg at one week to 29.7 +/- 9.8 mmHg at six months (p = 0.01); for 25 mm EPSV, peak gradient varied from 33.6 +/- 10.6 mmHg at one week to 29.5 +/- 6.5 mmHg at six months (p = N.S.). CONCLUSIONS: The EPSV, when used in the subcoronary position, has been associated with high early transprosthetic gradients which only partly regress at six months. Gradients are probably caused by the inward folding of the Dacron cloth beneath the right coronary ostium and were recorded especially in patients with aortic stenosis in whom the right coronary ostium was close to the aortic annulus. In such patients alternative implantation techniques should be considered.

Aged↗
PubMed1997

Reoperation for prosthetic thrombosis and acute neurologic injury.

Open-heart surgery in patients with recent cardiogenic embolic stroke represents a difficult management problem. We present a patient who developed thrombosis of a mitral tilting-disc prosthesis complicated by repeat cerebral embolic episodes that resulted in acute neurologic injury. We believe that in such patients the indication for reoperation must be individually evaluated but it is justified in young subjects, even in the presence of severe neurologic damage.

Adult↗
PubMed1997

Post-traumatic tricuspid valve insufficiency. 2 cases of delayed clinical manifestation.

We present 2 cases of tricuspid insufficiency following blunt chest trauma: 1 was diagnosed 5 months after the trauma and the other, 20 years after the trauma. In both patients, the tricuspid valve was replaced with a porcine bioprosthesis, because valve repair was not considered feasible. These cases emphasize the variability of clinical presentation of post-traumatic tricuspid valve insufficiency and indicate the need for close follow-up of patients after major thoracic trauma.

Adult↗
PubMed1997

[Transmyocardial revascularization with a holmium laser: preliminary results].

BACKGROUND: Transmyocardial laser revascularization (TMLR) aims to improve perfusion of the ventricular wall via laser-created transmural channels. We present the results of TMLR with a holmium laser as sole therapy in patients with angina refractory to medical treatment and extensive coronary artery disease unsuitable for angioplasty or coronary artery by-pass grafting. METHODS: From November 1995 to February 1997, twenty-two patients underwent isolated TMLR with a holmium laser. Five patients (23%) were female; the mean age was 67 +/- 7 years (range 53 to 74 years). Previous myocardial revascularization procedures had been performed in 17 patients (77%). Mean preoperative angina class was 3.4 +/- 0.5 and unstable angina was present in 7 patients (32%). RESULTS: There were no hospital deaths. The only postoperative complications were transient supraventricular arrhythmias in 6 patients (27%). Each patient received a mean of 33 +/- 8 channels in 27 +/- 13 minutes. There were two late deaths, 40 days and 4 months after TMLR, due to stroke and myocardial infarction, respectively. Mean follow-up duration was 8 +/- 5 months (range 40 days-15 months). The mean number of hospitalizations due to angina fell from 4.9 +/- 1.5 in the 6 months before TMLR to 1.5 +/- 1.0 in the 6 months following surgery (p < 0.001). At follow-up, mean angina class had significantly improved (1.8 +/- 0.6, p < 0.001), as well as effort tolerance, which increased from a mean of 3.5 +/- 1.4 minutes to 5.1 +/- 1.7 minutes (p = 0.01). 201Tl SPECT at 3 and 6 months did not show any significant changes in the segmental perfusion of the lased and unlased areas. CONCLUSIONS: TMLR with a holmium laser is a simple procedure with low operative mortality and morbidity. Short-term results confirm that clinical improvement is obtained in most patients, although this is not supported by significant changes in myocardial perfusion at short-term follow-up.

Aged↗
PubMed1997

Surgical angioplasty for isolated coronary ostial stenosis.

Patch angioplasty has been reported as a suitable surgical option for patients with isolated coronary ostial stenosis, but controversy still exists concerning its effectiveness. We report the cases of 4 additional patients in whom this procedure was performed, including that of a patient with bilateral ostial stenosis; and we review the literature pertaining to bilateral ostial stenosis. Four patients, 3 with isolated stenosis of the left main coronary ostium and 1 with bilateral ostial stenosis, had direct surgical ostioplasty from January through November 1994. We considered the cause of ostial stenosis to be aortitis (of suspected syphilitic origin) in 1 patient, atherosclerotic plaque in 2 patients, and a fibrous membrane in the 4th. Ostioplasty was performed with a patch of autologous pericardium in 3 patients (fresh pericardium in 2 and glutaraldehyde-fixed in 1) and a patch of saphenous vein in 1. There were no operative deaths. One patient underwent successful reoperation for left main coronary artery restenosis after 3 months. All other patients are asymptomatic at 16, 18, and 24 months postoperatively. In the patient who underwent bilateral ostioplasty, coronary angiography showed patent ostia at 1 year. Surgical ostioplasty should be considered in the treatment of patients who have isolated ostial stenosis but no distal coronary disease. Careful patient selection seems to be a prerequisite for surgical success.

Adult↗
PubMed1996

The katE gene, which encodes the catalase HPII of Mycobacterium avium.

Disseminated Mycobacterium avium-Mycobacterium intracellulare disease is a prevalent opportunistic infection in patients with acquired immune deficiency syndrome (AIDS). These pathogens are generally resistant to isoniazid (INH), a powerful antituberculosis drug. It is now generally accepted that the INH susceptibility of Mycobacterium tuberculosis results from the transformation of the drug into a toxic derivative, as a result of the action of the enzyme catalase-peroxidase (HPI), encoded by the katG gene. It has been speculated that the presence of a second catalase (HPII) in some mycobacterial species, but lacking in M. tuberculosis, may impair the action of INH. In this report, the nucleotide sequence of the M. avium katE gene, encoding catalase HPII, is described. This enzyme shows strong similarity to Escherichia coli catalase HPII and eukaryotic catalases. All amino acids previously postulated as participating directly in catalysis by liver catalase and most of the amino acids binding the prosthetic group are conserved in M. avium catalase HPII. The enzyme is expressed in E. coli and is inhibited by 3-amino-1,2,4-triazole (AT). Furthermore, Southern blot hybridizations and polymerase chain reaction experiments demonstrate the distribution of katE gene in several mycobacterial species. To evaluate the potentially antagonistic effect of HPII catalase on INH susceptibility, the katE gene was transformed into M. tuberculosis H37Rv and the minimum inhibitory concentration (MIC) for INH was determined. Despite strong expression of the katE gene, no change in MIC was observed, thus ruling out a possible contribution of this enzyme to the natural resistance of M. avium to the drug. The availability of the gene probe, encoding the second mycobacterial catalase HPII, should open the way for the development of new drugs and diagnostic tests to combat drug-resistant pathogen strains.

Amino Acid Sequence↗
PubMed1996

Evolution of focal moderate (International Society for Heart and Lung Transplantation grade 2) rejection of the cardiac allograft.

BACKGROUND: In the absence of clinical evidence of cardiac allograft rejection, it is still poorly defined whether the International Society for Heart and Lung Transplantation biopsy grade 2 (e.g., focal moderate rejection) should be treated. Aim of the present study was to retrospectively investigate the evolution of focal moderate rejection, diagnosed during the first postoperative year in patients who had undergone orthotopic heart transplantation. METHODS: A retrospective analysis was conducted on 256 International Society for Heart and Lung Transplantation grade 2 biopsies from 110 orthotopic heart transplantations; 125 episodes occurred within the first 3 months (group 1), 131 later (group 2). For each grade 2 diagnosis, two biopsies, one immediately before and one after, were analyzed and classified as follows: lower (grade 0 or 1), equal (grade 2), or higher (grade 3 or 4). RESULTS: Evolution of grade 2 rejection was to a lower grade in 66% of cases, an equal grade in 16.8%, and a higher grade in 17.2%, with differences between group 1 and 2 (higher: 25% versus 10%, respectively, p = 0.005). Episodes which progressed into higher grades occurred earlier compared with those which persisted or resolved (9.2 +/- 8.6 weeks versus 20.0 +/- 15.6, p < 0.001). Five-year actuarial survival and incidence of graft coronary disease were similar in patients whose conditions progressed and those whose conditions did not. However, left ventricular ejection fraction at 1 and 2 years was lower in patients whose conditions progressed compared with those whose conditions persisted or resolved (56% +/- 4% versus 66% +/- 2%, p = 0.004; 56% +/- 10% versus 64% +/- 8%, p = 0.02, respectively). CONCLUSIONS: Progression of grade 2 rejection occurred in a minority of cases and did not affect 5-year survival or incidence of coronary disease, but its relationship with long-term cardiac allograft dysfunction warrants further investigation.

Actuarial Analysis↗
PubMed1995

Extracorporeal photochemotherapy as adjuvant treatment of heart transplant recipients with recurrent rejection.

Recurrent rejection is an uncommon, severe complication after heart transplantation that is associated with a poor long-term prognosis. Photopheresis (ECP), a new form of extracorporeal photo-chemotherapy used for the treatment of cutaneous T cell lymphoma and several autoimmune diseases, has also been used for prevention and treatment of acute rejection in heart transplant recipients. It seems to induce specific suppression of both cellular and humoral rejection. In this study, we evaluated whether ECP added to standard therapies allowed better control of rejection and reduction of conventional immunosuppressive drugs in patients with repeated rejection episodes. Eight heart transplant recipients (6 men and 2 women, mean age 48 yr), with recurrent rejection were treated with ECP for 6 months. Endomyocardial biopsies (EMB) were performed monthly. As a result of treatment, 7 patients on ECP experienced a reduction of the number and severity of rejection episodes. The fraction of EMB negative for rejection increased from 13 to 41%, whereas the fraction of specimens with multifocal and/or diffuse moderate lymphocytes infiltration (grades 3A and 3B) decreased from 41 to 21%. ECP allowed reductions of daily immunosuppressive therapy: prednisone by 44% (16.9 vs. 9.4 mg), cyclosporine by 21% (366 vs. 291 mg), and azathioprine by 29% (137 vs. 97 mg). No major side effects were observed. We conclude that, although the number of patients is small, the use of ECP was safe and associated with improved control of recurrent rejection. This allowed tapering of immunosuppressive drugs, which was particularly useful in two patients with insulin-dependent diabetes and one with sternal wound osteomyelitis.

Adult↗
PubMed1995

Porcine valve durability: a comparison between Hancock standard and Hancock II bioprostheses.

Two series of patients who received a Hancock standard (HS) (1970 to 1983) and a Hancock II (HII) (1983 to 1992) porcine bioprosthesis were reviewed to compare bioprosthetic durability. Patients with HS porcine bioprostheses (n = 769) differed from those with HII bioprostheses mostly in mean age at operation (47 +/- 12 versus 62 +/- 9 years; p < 0.001); the latter prosthesis was implanted mostly in patients older than 50 years. At 8 years after operation, actuarial survival was 57% +/- 4% after aortic, 61% +/- 3% after mitral, and 39% +/- 7% after mitral-aortic valve replacement with the HS bioprosthesis; actuarial survival was 51% +/- 9% after aortic, 66% +/- 6% after mitral, and 49% +/- 10% after mitral and aortic valve replacement with an HII bioprosthesis. No cases of structural deterioration of HII bioprostheses were observed at 8 years in any patients. Actuarial freedom from structural valve deterioration was 78% +/- 4% after aortic, 88% +/- 3% after mitral, and 79% +/- 7% after mitral-aortic valve replacement with an HS bioprosthesis at 8 years. In all patients greater than 50 years of age, actuarial freedom from structural valve deterioration at 8 years was 90% +/- 3% in patients with an HS bioprosthesis and 100% in those with an HII bioprosthesis (p = 0.08). A trend to an improved durability of the HII bioprosthesis compared with the HS was observed during the first 8 postoperative years. Because these results could be influenced partly by the age difference in the two series of patients, a longer follow-up is needed to confirm these data.

Actuarial Analysis↗
PubMed1995

Recurrent thrombosis of Omniscience prostheses in the mitral position: a case report.

We report a patient who experienced thrombotic obstruction of an Omniscience prosthesis three years after mitral valve replacement. At reoperation another Omniscience prosthesis was inserted which became thrombosed after eight months. Recurrent thrombosis of the same prosthesis in the same patient is unusual and raises the problem of which device to use when replacing a thrombosed valve. In our patient another mechanical prosthesis was inserted at second reoperation because of her young age and in the hope of reducing the risk of further thrombosis by using a valve with better flow characteristics such as a bileaflet prosthesis.

Female↗