Biomedical subjects

M Sisti

Publications and source records attributed to M Sisti.

32 records · Page 2Linked to original sources

PubMed1997

Stereotactic angiographic localization as an adjunct to surgery of cerebral mycotic aneurysms: case report and review of the literature.

Less than 10% of all aneurysms affecting the arterial cerebral circulation are mycotic in nature. They occur in the setting of bacterial endocarditis and are the cause of considerable morbidity and mortality of affected patients. In selected cases surgery may play a curative role in the treatment plan. These aneurysms frequently arise in distal arterial branches, and their localization during surgery may at times prove laborious. We report the case of a mycotic aneurysm of a distal branch of the anterior cerebral artery surgically treated with the help of angiographic stereotactic localization. Stereotaxy should thus be regarded as a pertinent adjunct in selected cases of surgical treatment of distal mycotic cerebral aneurysms.

Cerebral Angiography↗

PubMed1997

Dobutamine and nitroprusside infusion in patients with severe congestive heart failure: hemodynamic improvement by discordant effects on mitral regurgitation, left atrial function, and ventricular function.

OBJECTIVES: In patients with severe heart failure additional therapeutic support with intravenous inotropic or vasodilator drugs is frequently used in the attempt to obtain hemodynamic control. The nature and extent to which diastolic filling, atrial function, and mitral regurgitation are modified by these drugs have not been fully explored. The aim of this study was to compare the acute adaptations of the left ventricular performance, left atrial function, and mitral regurgitation that accompanied hemodynamic improvement during intravenous dobutamine and nitroprusside infusions in patients with severe chronic heart failure. METHODS: Forty consecutive patients with severe heart failure were evaluated by simultaneous echo-Doppler and hemodynamic investigations at baseline and during nitroprusside and dobutamine administration. Mitral flow velocity variables, left atrial and ventricular volumes, left atrial reservoir, conduit and pump volumes, and mitral regurgitation jet area were compared by analysis of variance for repeated measurements. RESULTS: Nitroprusside increased cardiac output (2.1 +/- .5 vs 2.6 +/- .5 L/min/m2, p < 0.004), reduced left ventricular filling pressure (25 +/- 6 vs 14 +/- 4 mm Hg, p < 0.0001), and improved left atrial pump volume (19 +/- 3 vs 26 +/- 12 ml, p < 0.02) without variations in left atrial reservoir and conduit volume. The restoration of preload reserve and improvement of the atrial contribution to left ventricular diastolic filling were demonstrated by the Doppler mitral flow pattern, which moved from a restrictive to a normal pattern. Furthermore mitral regurgitation decreased in all patients (9 +/- 4.6 vs 4.6 +/- 3.4 cm2, p < 0.0001). Dobutamine increased cardiac output (2.1 +/- .5 vs 2.8 +/- .6 L/min/m2), but the effects on pulmonary wedge pressure and mitral regurgitation were variable and unpredictable. Left atrial reservoir and conduit volumes increased, whereas left atrial pump volume did not change (19 +/- 13 vs 22 +/- 14 ml, p = NS). Furthermore Doppler mitral flow showed a persistent restrictive pattern. CONCLUSIONS: In patients with advanced congestive heart failure both nitroprusside and dobutamine improve cardiac output, with different adaptations of left ventricular performance and left atrial function. Nitroprusside seems to restore both atrial and ventricular pump function better. Careful echo-Doppler monitoring during drug infusion provides information relevant to the clinical treatment of individual patients.

Atrial Function, Left↗

PubMed1997

Selective cochlear neurectomy for debilitating tinnitus.

Eighth nerve sections have been performed to control debilitating tinnitus, with various success rates (45% to 76%). Patients with a unilateral profound sensorineural hearing loss and disabling tinnitus perceived in that ear are candidates for such surgery. The concept of a selective cochlear neurectomy with preservation of the vestibular nerve is introduced with two case presentations. The indications for surgery, surgical technique, and results are described. Advantages of preserving the vestibular nerve fibers include the lack of postoperative vertigo and disequilibrium and thus a shorter length of hospital stay, and the conservation of a symmetric vestibular input, obviating the lengthy compensation process that might otherwise be needed, particularly in the elderly. A selective cochlear neurectomy for the control of debilitating tinnitus has proven to be successful in controlling tinnitus in the two patients presented, with the added advantage of preservation of their vestibular function. Further controlled studies are necessary to confirm the advantages and effectiveness of this technique.

Adult↗

PubMed1997

Age limits for heart transplantation: medical aspects.

OBJECTIVE: To contribute to the analysis of the medical issue of aging as a selection criteria for heart transplantation (HT) METHODS: Elderly candidates (52 subjects, aged > or = 60) were compared with younger patients (64 candidates, aged 50-55) in: clinical pattern (sex, etiology, duration of disease); laboratory and instrumental data (multiple organ function, hemodynamics, maximal and submaximal exercise capacity, nutritional status); follow-up (death, transplantation, status I, decompensation, complications) of at least 6 months. RESULTS: When compared with younger candidates, over 60 patients did not differ in clinical pattern, in all instrumental data, in end-organ function, in transplantation rate, in fatal and non-fatal cardiac events. In both groups the medical management was similarly complex. CONCLUSION: In regard to the medical issue, no reasons emerged to exclude older patients suitable from HT.

Aged↗

PubMed1996

Sentinel lesions of primary CNS lymphoma.

Some patients ultimately diagnosed with primary CNS lymphoma (PCNSL) have transient symptomatic contrast enhancing lesions. These "sentinel lesions" of PCNSL recede spontaneously or with corticosteroid treatment and present an important diagnostic dilemma because they show variable, but non-diagnostic histopathological features. Four previously healthy, immunocompetent patients aged 49 to 58 years had contrast enhancing intraparenchymal brain lesions. Before biopsy, three of the four were treated with corticosteroids. Initial biopsies showed demyelination with axonal sparing in two, non-specific inflammation in one, and normal brain in one. Infiltrating lymphocytes predominantly expressed T cell markers with rare B cells. All four patients recovered within two to four weeks after the initial biopsy and imaging studies showed resolution of the lesions. The CSF was normal in three of the four patients tested; oligoclonal bands were absent in both of the two tested. After seven to 11 months, each patient developed new symptomatic lesions in a different region of the brain, biopsy of which showed a B cell PCNSL. The mechanism of spontaneous involution of sentinel lesions is not understood, but may represent host immunity against the tumour. Sentinel lesions of PCNSL should be considered in patients with contrast enhancing focal parenchymal lesions that show non-specific or demyelinative histopathological changes. Close clinical and radiographic follow up is essential if PCNSL is to be diagnosed early in such patients.

Adrenal Cortex Hormones↗

PubMed1996

[Pulmonary venous flow in patients with chronic heart failure: feasibility and additional value compared to transmitral flow for non-invasive estimation of pulmonary wedge pressure].

BACKGROUND: In many cardiac conditions, Doppler of transmitral flow has been showed to be related to left ventricular filling pressure, but several factors may limit its practical value in estimating pulmonary wedge pressure in patients with chronic heart failure. Pulmonary venous velocities directly depend on the oscillations of left atrial pressure. Recent studies suggest that transthoracic Doppler of pulmonary venous flow provides a more accurate estimation of pulmonary wedge pressure. However the relative values of transmitral and pulmonary venous flow for assessing pulmonary wedge pressure in patients with chronic heart failure have not been fully classified until now. Accordingly, we performed this study to assess the feasibility of transthoracic Doppler of pulmonary venous flow in patients with chronic heart failure and to evaluate whether it provides additional information regarding pulmonary wedge pressure when compared with Doppler indices of transmitral flow. METHODS: Simultaneous Doppler echocardiographic examinations and right heart catheterizations were performed prospectively in 300 consecutive patients with chronic heart failure due to dilated cardiomyopathy. The correlations of mitral and pulmonary venous flow velocity variables, left atrial volumes, mitral regurgitation jet area and left ventricular ejection fraction with pulmonary artery wedge pressure were evaluated. RESULTS: A complete recording of transthoracic pulmonary venous flow including all components was obtained in 66% of patients, while only systolic and diastolic forward flow were recorded in 88% of patients. Several indices, derived from pulmonary venous flow, were correlated with pulmonary wedge pressure; the strongest correlation was between systolic fraction of peak velocities and pulmonary wedge pressure (r = -0.76). This value was similar to that obtained between deceleration rate (r = 0.78) and deceleration time (r = -0.67) of transmitral flow and pulmonary wedge pressure. A systolic fraction > 40% showed a greater positive predictive value than restrictive pattern of transmitral flow for identifying patients with pulmonary wedge pressure > 18 mmHg (95% vs 86% p < 0.05). This accuracy is confirmed also in patients who had a single peak of transmitral flow. CONCLUSIONS: Doppler of pulmonary venous flow can be performed in a high percentage of patients with chronic heart failure due to dilated cardiomyopathy. The indices derived from transthoracic pulmonary venous flow are strongly correlated with pulmonary wedge pressure and improve the noninvasive identification of patients with high pulmonary wedge pressure, even when transmitral flow pattern is difficult to be interpreted.

Aged↗

PubMed1995

Placebo-controlled trial of safety and efficacy of intraoperative controlled delivery by biodegradable polymers of chemotherapy for recurrent gliomas. The Polymer-brain Tumor Treatment Group.

Chemotherapy for brain tumours has been limited because of difficulty in achieving adequate exposure to the tumour without systemic toxicity. We have developed a method for local sustained release of chemotherapeutic agents by their incorporation into biodegradable polymers. Implantation of the drug-impregnated polymer at the tumour site allows prolonged local exposure with minimal systemic exposure. We conducted a randomised, placebo-controlled, prospective study to evaluate the effectiveness of biodegradable polymers impregnated with carmustine to treat recurrent malignant gliomas. In 27 medical centres, 222 patients with recurrent malignant brain tumours requiring re-operation were randomly assigned to receive surgically implanted biodegradable polymer discs with or without 3.85% carmustine. Randomisation balanced the treatment groups for all of the prognostic factors examined. Median survival of the 110 patients who received carmustine polymers was 31 weeks compared with 23 weeks for the 112 patients who received only placebo polymers (hazard ratio = 0.67, p = 0.006, after accounting for the effects of prognostic factors). Among patients with glioblastoma, 6-month survival in those treated with carmustine-polymer discs was 50% greater than in those treated with placebo (mortality = 32 of 72 [44%] vs 47 of 73 [64%], p = 0.02). There were no clinically important adverse reactions related to the carmustine polymer, either in the brain or systemically. Interstitial chemotherapy delivered with polymers directly to brain tumours at the time of surgery seems to be a safe and effective treatment for recurrent malignant gliomas.

Biodegradation, Environmental↗

PubMed1995

The safety of interstitial chemotherapy with BCNU-loaded polymer followed by radiation therapy in the treatment of newly diagnosed malignant gliomas: phase I trial.

The results of a multi-institutional phase I trial evaluating the safety of surgically implanted biodegradable 1,3-bis(chloro-ethyl)-1-nitrosourea (BCNU) impregnated polymer as the initial therapy for malignant brain tumors are reported. This is the first study of locally delivered BCNU and standard external beam radiation therapy (XRT) given concurrently. Twenty-two patients were treated at three hospitals. The entry criteria were: single unilateral tumor focus larger than 1 cm3; age over 18 years; Karnofsky Performance Score (KPS) of at least 60 h; and an intra-operative diagnosis of malignant glioma. Twenty-one of twenty-two patients had glioblastoma multiforme. After surgery, seven or eight BCNU-loaded polyanhydride polymer discs (7.7 mg BCNU each) were placed in the resection cavity. Postoperatively, all patients received standard radiation therapy; none received additional chemotherapy in the first 6 months. Neurotoxicity, systemic toxicity, and survival were assessed. No perioperative mortality was seen. Neurotoxicity was equivalent to that occurring in other series of patients undergoing craniotomy and XRT without local chemotherapy. Systematically, no significant bone marrow suppression occurred, and there were no wound infections. Median survival in this group of older patients (mean age = 60) was 42 weeks, 8 patients survived 1 year, and 4 patients survived more than 18 months. Interstitial chemotherapy with BCNU-polymer with subsequent radiation therapy appears to be safe as an initial therapy. Several long-term survivors in this group of older patients with predominantly glioblastoma suggests efficacy in some patients. Dose escalation and efficacy trials are planned to further evaluate interstitial chemotherapy for the initial treatment of malignant gliomas.

Adult↗

PubMed1995

MTS1/p16/CDKN2 lesions in primary glioblastoma multiforme.

The multiple tumor suppressor 1 (MTS1) gene encoding the p16 inhibitor of cyclin-dependent kinase 4 is deleted or mutated in a wide variety of human tumor cell lines, but the importance of this gene as a tumor suppressor in vivo appears to be highly dependent on tumor type. Because MTS1/p16/CDKN2 and the homologous MTS2/p15 gene map to a region of chromosome 9p21, which is frequently deleted in malignant gliomas, we searched for lesions of these genes in primary biopsies of glioblastoma multiforme (GBM). Our analysis confirms a sizable frequency of homozygous deletion of MTS1/p16/CDKN2 (9/27 cases) and also reveals a low but detectable frequency of intragenic DNA lesions (one point mutation in exon 2 leading to premature termination) among GBMs that retain one or both copies of the gene. No mutations were found in exon 2 of MTS2/p15 (12 cases examined), and one GBM showed a DNA deletion breakpoint in the 30 kb between MTS1/p16/CDKN2 and MTS2/p15 resulting in deletion of MTS1/p16/CDKN2 with retention of MTS2/p15. In contrast to the high-grade tumors, none of 12 low-grade gliomas showed MTS1/p16/CDKN2 deletions. These data support a role for MTS1/p16/CDKN2 as a tumor suppressor gene in the in vivo evolution of GBMs. Given that two tumors with hemizygous MTS1/p16/CDKN2 deletions and loss of heterozygosity for chromosome 9p21 did not contain detectable intragenic mutations, there may be one or more additional relevant 9p21 tumor suppressor genes.

Base Sequence↗

PubMed1994

Isolated kidney localization of invasive Aspergillosis in a patient with AIDS.

Although the importance of Aspergillus in AIDS is now increasing, extra-pulmonary disease is still an unusual event, especially when a single localization occurs. A case of isolated renal aspergilloma in an AIDS patient is described. At onset, no recognized risk factors were present in our patient. An early surgical approach combined with antifungal chemotherapy (amphotericin B, Itraconazole) led to a good control of the disease, with no evidence of recrudescence at 8 months' follow-up.

AIDS-Related Opportunistic Infections↗

PubMed1990

Intracerebral solitary plasmacytoma.

We report a rare occurrence of intraparenchymal plasmacytoma and review the literature. The clonal nature of the neoplasm is demonstrated by immunohistochemical and molecular techniques. The importance of the latter techniques in ruling out other pathological entities is stressed.

Blotting, Southern↗

PubMedDate not supplied

Novel paramagnetic macromolecular complexes derived from the linkage of a macrocyclic Gd(III) complex to polyamino acids through a squaric acid moiety.

Macromolecular Gd(III) complexes may find useful application as contrast agents for magnetic resonance angiography (MRA). Herein two novel systems are reported, namely Gd(DO3ASQ)3-lys16 and Gd(DO3ASQ)30-orn114. Their syntheses are based on the ability of the squaric acid moiety to act as a linker between the DO3A (1,4,7, 10-tetraazacyclododecane-1,4,7-triacetic acid) chelate moiety and the polyamino acidic chain. Moreover, the squaric acid participates in the coordination cage of the Gd(III) ion. The investigation of 1H and 17O NMR relaxation processes of solvent water nuclei allowed a detailed characterization of the systems under study. Gd(DO3ASQ)30-orn114 displays a remarkable ability to enhance the water proton relaxation rate of its solutions, and it may be considered as potential contrast agent for MRA applications.

Contrast Media↗

PubMedDate not supplied

Rapid dose calculations for stereotactic radiosurgery.

A three-dimensional dose calculation algorithm is described for stereotactic radiosurgery using multiple noncoplanar beam arcs. Precalculated dose libraries of 20-deg arc segments, or mini arcs, are stored in computer memory which permits rapid calculation of complete, high resolution, three-dimensional isodose distributions and dose volume histograms. Three-dimensional patient contours and target volumes are obtained from CT scans and angiographic x rays. Rapid dose calculations are made possible by the use of arc libraries and an improved algorithm for mapping beam doses to the dose calculation grid. This permits more flexibility in designing optimum treatment plans, as five-six complete plans can be generated in less than 1 h. Thus many possible treatment options can be tested in the 3-4-h time period typically available in stereotactic procedures between CT scanning and treatment.

Algorithms↗

PubMedDate not supplied

[Disinfection efficiency of peracetic acid, alone and in combination with hypochlorite, against Mycobacterium avium in drinking water].

Peracetic acid (PAA) is a disinfectant with a wide spectrum of antimicrobial activity, but little is known about the feasibility of using it in the field of drinking water treatment. The aim of this study has been assess disinfectant efficacy of PAA, alone or in combination with hypochlorite, against M. avium in drinking water M. avium is a common opportunistic pathogen in immunocompromised subjects that is able to survive and grow in drinking water distribution systems. In this study PAA did not show appreciable activity against the greater number of tested strains (16/21) up to 5 ppm of PAA, a weak activity was seen on 4 strains, while a significant reduction in viable cells (about 50%) was seen only on 1 strain after 48 h of treatment with 5 ppm of PAA. We also evidenced that M. avium was unaffected by chlorine concentration usually present in drinking water distribution system. Finally, the combination of PAA and sodium hypochlorite did not promote enhanced antimicrobial efficacy respect to the single disinfectants. In conclusion, our result would indicate that PAA is an unlikely candidate for the disinfection of drinking water from M. avium and further strategies are required to eliminate M. avium from drinking water system.

Disinfectants↗