Biomedical subjects

A Puglisi

Publications and source records attributed to A Puglisi.

At least 19 recordsLinked to original sources

PubMed2005

Pyramid sensor for segmented mirror alignment.

We report what is to our knowledge the first laboratory experiment that shows the use of a pyramid wavefront sensor to cophase and align segmented mirrors having three degrees of freedom per segment, i.e., piston, tip, and tilt. In the laboratory the iterative alignment procedure reached a wavefront residual error of about 10 nm. The residual error was equally distributed between piston, tip, and tilt. These results demonstrate that the pyramid can successfully simultaneously sense the piston, tip, and tilt of a segmented mirror. This last feature makes this technique very attractive in phasing and aligning astronomical segmented telescopes such as extremely large telescopes currently under extensive studies.

Journal Article↗

PubMed2005

Neoadjuvant chemotherapy and pneumonectomy in a lung cancer patient on hemodialysis.

Major pulmonary resections are rarely performed in non-small cell lung cancer patients on hemodialysis. To date only two cases of pneumonectomy performed in such patients are reported in the literature. Moreover, chemotherapy, as a treatment for advanced non-small cell lung cancer, is not routinely administered to patients with end-stage renal disease requiring hemodialysis. We present the case of a stage IIIB non-small cell lung cancer patient on hemodialysis who successfully underwent neoadjuvant chemotherapy followed by pneumonectomy. To our knowledge, this is the first case of non-small cell lung cancer patient on hemodialysis reported in the literature who successfully underwent this type of combined therapy.

Carcinoma, Non-Small-Cell Lung↗

PubMed2003

Statistical mechanics of granular gases in compartmentalized systems.

We study the behavior of an assembly of N granular particles contained in two compartments within a simple kinetic approach. The particles belonging to each compartment collide inelastically with each other and are driven by a stochastic heat bath. In addition, the fastest particles can change compartment at a rate that depends on their kinetic energy. Via a Boltzmann velocity distribution approach, we first study the dynamics of the model in terms of a coupled set of equations for the populations in the containers and their granular temperatures and find a crossover from a symmetric high-temperature phase to an asymmetric low-temperature phase. Finally, in order to include statistical fluctuations, we solve the model within the direct simulation Monte Carlo approach. Comparisons with previous studies are presented.

Journal Article↗

PubMed2003

Impact of Closed-Loop Stimulation, overdrive pacing, DDDR pacing mode on atrial tachyarrhythmia burden in Brady-Tachy Syndrome. A randomized study.

AIMS: Atrial overdrive pacing algorithms increase Atrial Pacing Percentage (APP) to reduce Atrial Tachyarrhythmia (AT) recurrences in patients with Brady-Tachy Syndrome (BTS). This study aimed to compare AT burden and APP in BTS patients treated with conventional DDDR pacing, DDD+ overdrive or Closed-Loop Stimulation (CLS). METHODS AND RESULTS: One hundred and forty-nine BTS patients were included (72 male, mean age 74+/-9), who received a dual chamber pacemaker (Philos DR or Inos 2+CLS, Biotronik GmbH, Berlin, Germany) programmed in DDD at 70min(-1). At 1-month follow-up, DDDR, DDD+ or CLS algorithms were activated according to randomization. Follow-up visits for data collection were performed at 4 and 7 months. Non parametric statistical tests (Kruskal-Wallis H-test, Dunn test, Spearman coefficient) were used to analyse not-normally-distributed samples. At 7 months, AT burden was significantly lower in CLS group (20.3+/-63.1min/day, P<0.01) compared to DDDR (56.0+/-184.0min/day) and DDD+ group (63.1+/-113.8min/day). APP was higher in CLS (89.0+/-13.2%) and in DDD+ group (97.9+/-2.7%) than in DDDR group (71.1+/-26.7%, P<0.001). The correlation found between AT burden and APP was very weak: at 7-month follow-up the Spearman coefficient was -0.29 (P=NS) in CLS, -0.52 (P<0.01) in DDD+, -0.22 (P=NS) in DDDR. CONCLUSIONS: CLS pacing was associated with a significantly lower AT burden,compared to the other pacing algorithms. Moreover APP was significantly higher in DDD+ and in CLS mode, than in DDDR. APP weakly correlated with AT burden only in DDD+ mode, though the lowest AT burden level was obtained in the CLS group where no significant correlation was found.

Aged↗

PubMed2002

Fluctuation-dissipation relations in driven granular gases.

We study the dynamics of a two-dimensional driven inelastic gas, by means of direct simulation Monte Carlo techniques, i.e., under the assumption of molecular chaos. Under the effect of a uniform stochastic driving in the form of a white noise plus a friction term, the gas is kept in a nonequilibrium steady state characterized by fractal density correlations and non-Gaussian distributions of velocities; the mean-squared velocity, that is the so-called granular temperature, is lower than the bath temperature. We observe that a modified form of the Kubo relation, which relates the autocorrelation and the linear response for the dynamics of a system at equilibrium, still holds for the off equilibrium, though stationary, dynamics of the systems under investigation. Interestingly, the only needed modification to the equilibrium Kubo relation is the replacement of the equilibrium temperature with an effective temperature, which results equal to the global granular temperature. We present two independent numerical experiments, where two different observables are studied: (a) the staggered density current, whose response to an impulsive shear is proportional to its autocorrelation in the unperturbed system and (b) the response of a tracer to a small constant force, switched on at time t(w), which is proportional to the mean-square displacement in the unperturbed system. Both measures confirm the validity of Kubo's formula, provided that the granular temperature is used as the proportionality factor between response and autocorrelation, at least for not too large inelasticities.

Journal Article↗

PubMed2002

Cooling of a lattice granular fluid as an ordering process.

We present a microscopic model of granular medium to study the role of dynamical correlations and the onset of spatial order induced by the inelasticity of the interactions on the velocity field. In spite of its simplicity and intrinsic limitations, it features several aspects of the rich phenomenology observed in granular materials and allows to make contact with other topics of statistical mechanics such as diffusion processes, domain growth, aging phenomena. Interestingly, while local observables, being controlled by the largest wavelength fluctuations, seem to suggest a purely diffusive behavior, the formation of spatially extended structures and topological defects, such as vortices and shocks, reveals a more complex scenario. Finally, only for quasielastic systems, we observe a neat scale separation, which represents a fundamental hypothesis to develop a granular hydrodynamics.

Journal Article↗

PubMed2001

Driven granular gases with gravity.

We study fluidized granular gases in a stationary state determined by the balance between external driving and bulk dissipation. The two considered situations are inspired by recent experiments, where gravity plays a major role as a driving mechanism: in the first case, gravity acts only in one direction and the bottom wall is vibrated; in the second case, gravity acts in both directions and no vibrating walls are present. Simulations performed under the molecular chaos assumption show averaged profiles of density, velocity, and granular temperature that are in good agreement with the experiments. Moreover, we measure velocity distributions that show strong non-Gaussian behavior, as experiments pointed out, but also density correlations accounting for clustering, at odds with the experimental results. The hydrodynamics of the first model is discussed and an exact solution is found for the density and granular temperature as functions of the distance from the vibrating wall. The limitations of such a solution, in particular in a broad layer near the wall injecting energy, are discussed.

Journal Article↗

PubMed2001

Thoracoscopic techniques in the management of benign mediastinal dumbbell tumors.

Mediastinal dumbbell tumors can be resected with a variety of open surgical approaches. Recently, thoracoscopic techniques have been suggested for the treatment of benign neurogenic lesions. Over a 5-year period, three patients with a benign mediastinal dumbbell tumor were treated via a combined microneurosurgical and thoracoscopic approach. The neurosurgical phase consisted of a posterior laminectomy to free the tumor from the spinal cord, followed by an intervertebral foraminotomy. Thoracoscopic resection of the lesion was then performed in the same setting. The operative times were 240, 260, and 280 min, and there were no operative complications. The postoperative stays were 6, 7, and 7 days; the postoperative period was uneventful in all three patients. Pathologic examination revealed a benign schwannoma in two cases and an angiolipoma in one case. One patient reported the onset of paraesthesia in the left hypocondrium on the distribution area of the transected T10 and T11 intercostal nerves; slight paraesthesia still remains 15 months from surgery. We conclude that the combined posterior neurosurgical and thoracoscopic approach is a safe and effective method for the removal of benign mediastinal dumbbell tumors, whether neurogenic or nonneurogenic in origin.

Adult↗

PubMed2001

Impact of consistent atrial pacing algorithm on premature atrial complexe number and paroxysmal atrial fibrillation recurrences in brady-tachy syndrome: a randomized prospective cross over study.

AIM OF THE STUDY: The Consistent Atrial Pacing (CAP) algorithm has been designed to achieve a high percentage of atrial pacing to suppress paroxysmal atrial fibrillation. The aim of our study was to compare the impact of DDDR+CAP versus DDDR pacing on paroxysmal atrial fibrillation recurrences and triggers in patients with Brady-Tachy Syndrome. METHODS: 61 patients, 23 M and 38 F, mean age 75+/-9 y, affected by Brady-Tachy Syndrome, implanted with a DDDR pacemaker, were randomized to DDDR or DDDR+CAP pacing with cross over of pacing modality after 1 month. RESULTS: 78 % of patients in DDDR pacing and 73 % in DDDR + CAP pacing (p=n.s.) were free from symptomatic paroxysmal atrial fibrillation recurrences. During DDDR+CAP pacing, the atrial pacing percentage increased from 77+/-29 % to 96+/-7 % (p<0.0001). Automatic mode switch episodes/day were 0.73+/-1.09 in DDDR and 0.79+/-1.14 (p=n.s.) in DDDR+CAP. In patients with less than 50 % of atrial pacing during DDDR, automaticmode switch episodes/day decreased during DDDR+CAP from 1.13+/-1.59 to 0.23+/-0.32 (p<0.05) and in patients with less than 90 % from 1.23+/-1.27 to 0.75+/-1.10 (p<0.001). The number of premature atrial complexes per day decreased during DDDR + CAP from 2665+/-4468 to 556+/-704 (p<0.02). CONCLUSION: CAP algorithm allowed continuous overdrive atrial pacing without major side effects. Triggers of paroxysmal atrial fibrillation induction, such as premature atrial complexes, were critically decreased. Paroxysmal atrial fibrillation episodes were reduced in patients with atrial pacing percentage lower than 90 % during DDDR pacing.

Aged↗

PubMed2001

Randomized crossover comparison of right atrial appendage pacing versus interatrial septum pacing for prevention of paroxysmal atrial fibrillation in patients with sinus bradycardia.

BACKGROUND: New atrial pacing techniques and overdrive pacing algorithms have been introduced to prevent atrial fibrillation. This study was designed to test the hypotheses that (1) interatrial septum pacing (IASP) at the triangle of Koch would be more effective than right atrial appendage pacing (RAAP) in preventing paroxysmal atrial fibrillation (PAF) in patients with sinus bradycardia and (2) an algorithm (CAP) designed to achieve constant atrial capture would increase the efficacy of rate-responsive atrial pacing. METHODS: We studied 46 patients with PAF and sinus bradycardia implanted with a DDD(R) (Medtronic Thera) pacemaker. Twenty-four patients (6.0 +/- 10.1 PAF episodes/month within 3 months before study) were randomized to RAAP and 22 patients (5.4 +/- 7.1, not significant) to IASP. Within each arm 2 randomized crossover periods of CAP-OFF and CAP-ON function were programed. RESULTS: The PAF episodes per month significantly decreased in the RAAP (CAP-OFF: 2.1 +/- 4.2, P <.05; CAP-ON: 1.9 +/- 3.8, P <.05) and in the IASP group (CAP-OFF: 0.2 +/- 0.5, P <.05; CAP-ON: 0.2 +/- 0.5, P <.05). Values were significantly lower in the IASP group than in the RAAP group in both CAP-OFF (0.2 +/- 0.5 vs 2.1 +/- 4.2, P <.05) and CAP-ON (0.2 +/- 0.5 vs 1.9 +/- 3.8, P <.05) conditions. PAF burden was significantly lower in the IASP than in the RAAP group in CAP-OFF (47 +/- 84 min/d vs 140 +/- 217, P <.05) and in CAP-ON (41 +/- 72 vs 193 +/- 266, P <.05) conditions. No differences were observed within each arm in PAF burden between the 2 crossover CAP programing periods. CONCLUSIONS: Rate-adaptive IASP at the triangle of Koch is more effective than RAAP in preventing PAF in patients with sinus bradycardia. In our sample of patients no additional clinical benefit is furnished by the CAP algorithm.

Aged↗

PubMed2001

Modifications in cardiovascular functional parameters with aging.

BACKGROUND: The constant rise in the number of old people involves a great interest towards the aging of the cardiovascular system. Many authors have studied age-adjusted limits to echocardiographic and functional parameters. The aim of this study is to evaluate some functional parameters so as to define the cardiovascular modifications of the aging heart. METHODS: We have studied 66 patients, 32 of mean age 71+/-4 years (Group 1) and 34 with mean age 33+/-6 years (Group 2), without cardiovascular diseases, through basal echocardiography and exercise test. RESULTS: In comparison to group 2, in group 1 we have observed at rest normal ventricular dimensions with increase of the thickness (SIV 11.2+/-0.4 vs 9+0.6, p=0.01; PP 10.6+/-0.6 vs 9.2+0.4, p=0.01), of the left atrium (41.2+/-1.08 vs 36.2+1.3, p=0.05), and of the aortic root (33.2+/-1.3 vs, 30.8+0.9, p=0.05), altered diastolic function (E/A 0.7+/-0.14 vs 1.9+/-0.7, p=0.01), with normal systolic indexes. At 100 Watts workload there was an age-related increase in end-diastolic volume (142+/-10.6 vs 127+/-4.3, p=0.01) and an age related decrease in heart rate (HR 100 W 148+/-10.7 vs 169+/-10.9, p=0.05). CONCLUSIONS: In the heart of an elderly subject therefore there are morphological modifications that in the absence of organic pathologies can support the metabolic demands of the organism and adapt to the physiological modifications of the elderly subject.

Adaptation, Physiological↗

PubMed2001

[Treatment of malignant pleural mesothelioma].

BACKGROUND: In this study all patients observed between January 1993 and October 1997 with malignant pleural mesothelioma (MPM) have been analyzed in order to describe the impact of treatment modality on survival. METHODS: Medical records of 56 patients with MPM (44 male, 12 female, median age = 59 yrs) were reviewed. In 34 cases the histotype was epithelial, in 4 sarcomatoid, in 4 mixed, in 3 desmoplastic, and in 11 not specified. Four treatment modalities were identified: 1) Surgery (subtotal pleurectomy) = 20 patients; 2) Chemotherapy = 19 patients; 3) Surgery+Chemo-therapy = 8 patients; 4) Supportive care = 9 patients. RESULTS: The median survival was: 1) Surgery = 12.4 months; 2) Chemotherapy = 7.5 months; 3) Surgery+Chemotherapy = 12 months; 4) Supportive care = 11.4 months. Using univariate analysis, 8 prognostic factors were studied (age, sex, asbestos exposure, side, histotype, performance status, stage, treatment). Among these, only the stage and the performance status had shown a prognostic value on survival (p<0.05), while the treatment modality had not significantly influenced the prognosis. Using multivariate analysis only performance status showed to be significatively associated with survival (p=0.01 and odds ratio = 1.9, I.C. 1.2-3.2). CONCLUSIONS: Despite the limits of a retrospective study, personal experience confirms the ineffectiveness of current therapeutical approaches to MPM. A better understanding of MPM is required to develop new therapeutical approaches and alter the dismal prognosis of this disease.

Adult↗

PubMed2000

Latest generation of unipolar and bipolar steroid eluting leads: long-term comparison of electrical performance in atrium and ventricles.

One hundred and seventy-three patients, mean age 74 years permanently paced with 123 atrial (53 unipolar, 70 bipolar) and 143 ventricular (73 unipolar, 70 bipolar) pacing leads were included in this study. The pacing leads were recent generation low surface area steroid eluting leads from one manufacturer: leads with silicone and polyurethane insulation were studied, and they were combined with generations of one pacemaker family from the same manufacturer permitting identical measurements to be made over a follow-up of 2 years. Pacing threshold was measured using pulse duration at a fixed voltage of 1.5 V: peak to peak P and R wave amplitude and pacing impedance at 2.5 V and 0.5 ms were all measured using the manufacturer's standard programmer. Although many significant differences, in the parameters measures, existed between atrium and ventricle and unipolar and bipolar configurations, none was felt to be of clinical significance. These data permit the physician to choose the lead type with regard to sensing performance and long-term lead integrity.

Adult↗

PubMed2000

[Congenital lobar emphysema in adults].

Due to the severity of respiratory symptoms, congenital lobar emphysema often requires surgical treatment in the early stages of life. Diagnosis of congenital lobar emphysema in adult life is therefore unusual, often presenting with mild symptoms. Diagnostic assessment is therefore of great importance in the treatment of these patients. A case of congenital lobar emphysema in an adult is reported and the diagnostic and therapeutical approach are discussed. The use of new diagnostic techniques such as dynamic RMN and SPET V/Q lung scan may improve the accuracy of the diagnostic evaluation. Pulmonary lobectomy led to marked improvement in respiratory function. Accurate diagnosis and appropriate management of congenital lobar emphysema in adult patients can lead to favourable results.

Adult↗

PubMed2000

Laparoscopic radiofrequency thermal ablation of hepatocarcinoma: preliminary experience.

The objective was to evaluate the feasibility, safety, and effectiveness of radiofrequency thermal ablation (RFT), performed during laparoscopy with a cooled-tip electrode needle, in the treatment of neoplastic hepatic focal lesions. Seven patients with hepatocarcinoma (10 hepatic lesions) were treated during laparoscopy with RFT using a 100-watt RF generator and 17-gauge, dual-lumen, cooled-tip electrode needles with a 3-cm exposed tip. The mean exposure time was 12 minutes for each needle insertion. Spiral computed tomography scanning detected complete tumor necrosis in nine lesions; in one lesion, peripheral neoplastic tissue was detected, and percutaneous RFT was performed. Two patients during follow-up developed two new neoplastic lesions, treated with percutaneous ethanol injection. No recurrences of the treated lesions were seen after 6 months of follow up. Intraoperative RFT with a cooled-tip electrode needle is a safe and effective local treatment of hepatic focal lesions during laparoscopic surgery. Possible indications are large hepatocarcinoma (>5 cm), superficial lesions, multiple lesions, or tumor located near vascular or biliary structures.

Aged↗

PubMed1999

Tuning somatic hypermutation by transcription.

The dependence of somatic hypermutation on transcription was studied in three mutant immunoglobulin heavy chain (IgH) insertion mice in which a targeted non-functional VHB1-8 passenger transgene was either placed under the transcriptional control of a truncated DQ52 promoter (p delta), its own RNA polymerase II dependent IgH promoter (pII) or a RNA polymerase I dependent promoter (pI). The relative mutation-frequency of the VHB1-8 passenger transgene in memory B cells of p delta, pI and pII mice (7%, 60% and 100%) correlated with the relative levels of transgene-specific pre-mRNA expressed in germinal center B cells isolated from the mutant mice (8%, 72% and 100%, respectively). These data indicate that the mutation load of rearranged Ig genes can be tuned by transcription. The question, whether somatic hypermutation requires transcription per se or a specific component of the RNA polymerase II complex, is under investigation.

Animals↗

PubMed1999

Improvement of pulmonary function after lobectomy for non-small cell lung cancer in emphysematous patients.

OBJECTIVE: Pulmonary emphysema is frequently associated with lung cancer and, because of the impaired pulmonary function involved, it may contraindicate surgical treatment. However, improvement of pulmonary function has been observed after surgical resection in patients with advanced emphysema. The aim of this study was to evaluate whether pulmonary emphysema, as assessed by pulmonary function tests and radiological evaluation, can influence postoperative respiratory function after lobectomy for non-small cell lung cancer (NSCLC). METHODS: Respiratory function was evaluated before and after lobectomy for NSCLC. Radiological evaluation of emphysema was performed on chest X-ray and CT scan. Patients that had undergone chemo- or radiotherapy or had segmental or lobar atelectasis were excluded from the study. RESULTS: Thirty-five patients entered the study. A decrease in static lung volumes was observed after surgery. Total lung capacity (TLC) decreased from 6.58+/-0.92 to 5.46+/-0.77 l; functional residual capacity (FRC) from 3.70+/-0.88 to 2.96+/-0.73 1 and residual volume (RV) from 2.93+/-0.78 to 2.2+/-0.53 l. However, in a subgroup of 10 patients (Group 1), dynamic volumes after surgery were unchanged or slightly increased (forced vital capacity (FVC) from 3.23+/-0.65 to 3.3+/-0.68 l; forced expiratory volume in 1 s (FEV1) from 2.14+/-0.51 to 2.25+/-0.54 l), and airway resistances (sRaw) decreased from 15.58+/-5.18 to 11.42+/-5.25 cm H2O/s. Preoperative data showed that these patients had a greater obstruction, with FEV1 changing from 69+/-12.42 to 72.70+/-13.72% of predicted, as compared with a change from 87+/-12.7 to 72.08+/-13.10% in the other group of 25 patients (Group 2). Correlation analysis reached statistical significance between FEV1% variation (deltaFEV1%) and preoperative FEV1 and FVC% (r = -0.49, P = 0.002 and r = -0.5, P = 0.001, respectively) and between delta (FEV1)% and radiological scores for 3-level CT (r = 0.39, P = 0.04) and the sum of chest X-ray, single and 3-level CT scores (r = 0.49, P = 0.01). CONCLUSIONS: Pulmonary function may remain unchanged or even increase after lobectomy in patients with a pronounced emphysematous component of airway obstruction. The identification of preoperative parameters that identify this group of patients could extend the indications for the treatment of lung cancer in patients with pulmonary emphysema.

Aged↗

PubMed1999

Dual chamber pacing with optimal AV delay in congestive heart failure: a randomized study.

AIM: A prospective randomized trial was set up to evaluate contractile parameters and quality of life in patients with congestive heart failure. METHODS AND RESULTS: We describe the results from 38 patients in sinus rhythm and with chronic heart failure due to congestive cardiomyopathy, prospectively randomized to optimal medical therapy (Group 1, 19 patients) or optimal medical therapy plus dual chamber pacemaker programmed to optimal AV delay (Group 2, 19 patients). At a 6 month follow-up, 7/19 patients in Group 1 had died compared with 5/19 patients in Group 2. During follow-up, there were few significant changes in evaluated parameters except for mitral regurgitation time, which was prolonged in Group 1 and shortened in Group 2. The systolic left ventricular diameter shortened significantly only in Group 2. An energy and activity questionnaire showed that the effect of DDD pacing in the latter patient population was beneficial. CONCLUSIONS: From these results we may conclude that at the 6 month follow-up DDD pacing with echo-optimized AV interval programming can improve quality of life without affecting survival.

Aged↗