Tracheal replacement with aortic allografts.
Explore the source record for details and available documents.
Aorta↗
Biomedical subjects
Massimo Conti
Publications and source records attributed to Massimo Conti.
A new bioabsorbable sleeve for lung staple-line reinforcement (FOREseal): report of a three-center phase II clinical trial.
OBJECTIVE: To investigate on the feasibility, safety, and effectiveness of a new bioabsorbable material for lung staple-line reinforcement. METHODS: This prospective open trial included 66 patients (mean age of 56+/-17 years) who underwent various types of lung resection using staplers with knitted calcium alginate sleeves for buttressing (FOREseal, Laboratoires Brothier, Nanterre, France) at three academic centers: 29 lobectomies, 22 emphysema surgeries, 15 wedge resections or lung biopsies. Intraoperative air leakage was assessed at a mean respiratory peak pressure of 30 cmH2O, and rated as grade 1, 2, or 3. Persistent air leakage in the postoperative course, as well as any relevant event, was assessed daily. The follow-up period was of 6 months. RESULTS: No technical problem linked to the device occurred. Hemostasis of the cutting edges was completed in all patients. Fifty-six percent of the patients had no intraoperative air leak and 27.3% had grade 1 leaks. Mean postoperative air leaks and thoracic drainage times were 1.9+/-2.3 days and 6+/-5.3 days, respectively. In-hospital mortality was nil. There was no empyema. Mean hospital stay was 9.1+/-6.6 days. At follow-up, one patient underwent lung transplantation, and pathology of the explanted specimen showed the absence of device-related foreign-body inflammation. One patient complained from metalloptysis, and another one, with a metastatic invasive aspergillosis, developed an infectious recurrence that required reoperation. CONCLUSIONS: FOREseal is an ergonomic, safe, and promising new material instead of nonabsorbable materials and xenomaterials for staple-line reinforcement. A randomized comparative study is now in progress.
Absorbable Implants↗
Soluble mesothelin-related peptides in the diagnosis of malignant pleural mesothelioma.
BACKGROUND: Diagnosis of malignant pleural mesothelioma is a challenging issue. Potential markers in mesothelioma diagnosis include soluble mesothelin-related peptides (SMRPs) and osteopontin, but no subsequent validation has been published yet. METHODS: We prospectively evaluated SMRPs in serum and pleural effusion from patients with mesothelioma (n = 74), pleural metastasis of carcinomas (n = 35), or benign pleural lesions associated with asbestos exposure (n = 28), recruited when first suspected for mesothelioma. FINDINGS: Mean serum SMRP level was higher in patients with mesothelioma (2.05 +/- 2.57 nM/L [median +/- interquartile range]) than in patients with metastasis (1.02 +/- 1.79 nM/L) or benign lesions (0.55 +/- 0.59 nM/L). The area under the receiver operating characteristic curve (AUC) for serum SMRP was 0.872 for differentiating mesothelioma and benign lesions, cut-off = 0.93 nM/L (sensitivity = 80%, specificity = 82.6%). The AUC for serum SMRP differentiating metastasis and mesothelioma was 0.693, cut-off = 1.85 nM/L (sensitivity = 58.3%, specificity = 73.3%). SMRP values in pleural fluid were higher than in serum in all groups (mesothelioma: 46.1 +/- 83.2 nM/L; benign lesions: 6.4 +/- 11.1 nM/L; metastasis: 6.36 +/- 21.73 nM/L). The AUC for pleural SMRP-differentiating benign lesions and mesothelioma was 0.831, cut-off = 10.4 nM/L (sensitivity = 76.7%, specificity = 76.2%). The AUC for pleural SMRP-differentiating metastasis and mesothelioma was 0.793. INTERPRETATION: We show that SMRPs may be a promising marker for mesothelioma diagnosis when measured either in serum or pleural fluid. The diagnostic value of SMRPs was similar in both types of samples, but pleural fluid SMRPs may better discriminate mesothelioma from pleural metastasis.
Aged↗
Management of postintubation tracheobronchial ruptures.
STUDY OBJECTIVES: To determine whether nonoperative management can be applied to iatrogenic postintubation tracheobronchial rupture (TBR). DESIGN: Prospective cohort study. PATIENTS AND INTERVENTIONS: Thirty consecutive patients with TBR complicating intubation between June 1993 and December 2005 entered the study. Patients not receiving mechanical ventilation at time of diagnosis were treated nonsurgically. Patients receiving mechanical ventilation who were judged operable underwent surgical repair, while nonoperable candidates had their TBR bridged by endotracheal tubes. RESULTS: Fifteen patients not requiring mechanical ventilation underwent simple conservative management. TBR length measured 3.85 +/- 1.46 cm (mean +/- SD). Eight TBRs showed full-thickness rupture with frank anterior intraluminal protrusion of the esophagus. In three patients, transient noninvasive positive pressure ventilatory support (NIV) was necessary. All lesions healed without sequelae. Two patients receiving mechanical ventilation underwent surgical repair and died. Thirteen patients receiving mechanical ventilation were considered at high surgical risk, and TBR bridging was attempted as salvage therapy. Complete bridging was achieved in five patients by simply advancing the endotracheal tube distal to the injury. Separate bilateral mainstem endobronchial intubation was necessary in six patients whose TBRs were too close to the carina. Nine of 13 patients (69%) treated with nonoperative therapy completely recovered. CONCLUSION: We conclude that conservative nonoperative therapy should be considered in patients with postintubation TBR who are breathing spontaneously, or when extubation is scheduled within 24 h from the time of diagnosis, or when continued ventilation is required to treat an underlying respiratory status. Surgical repair should be reserved for cases in which NIV or bridging the lesion is technically not feasible.
Adult↗
Tissue inhibitor of metalloproteinase 1 is an independent predictor of prognosis in patients with nonsmall cell lung carcinoma who undergo resection with curative intent.
BACKGROUND: Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) play a role in the processes of extracellular matrix degradation. Changes in their expression levels have been observed in various tumor types, including lung carcinoma. However, their clinical significance and their prognostic importance in the progression of nonsmall cell lung carcinoma (NSCLC) remain to be specified. In this study, mRNA expression levels of MMP-1, MMP-9, TIMP-1, and TIMP-2 were evaluated in patients with resected NSCLC, and their associations with disease progression and prognosis were determined. METHODS: Between June 1996 and December 1999, 116 patients underwent resection for NSCLC. Expression levels of MMPs and TIMPs were evaluated using Northern blot analysis in these NSCLC tissue samples and in 39 matched samples of normal lung tissue. RESULTS: MMP-1, MMP-9, and TIMP-1 expression levels were increased in tumor samples compared with matched, corresponding normal tissues. In contrast, TIMP-2 expression was decreased in tumor samples. MMP-1 tumor expression was correlated significantly with the evolution of lymph node status and tumor-lymph node-metastasis (TNM) stage. In contrast, MMP-9 tumor expression was correlated significantly with increased T stage. TIMP-1 overexpression was an independent predictor of worse survival in patients with NSCLC that was not associated with other prognosis factors, such as TNM stage. CONCLUSIONS: The overexpression of TIMP-1 was an independent prognostic marker in patients with NSCLC, and evaluating TIMP-1 may be important for identifying patients who are at greater risk of disease recurrence.
Adenocarcinoma↗
Familial occurrence of thymoma and autoimmune diseases with the constitutional translocation t(14;20)(q24.1;p12.3).
Thymomas are low-grade epithelial cancers of the thymus whose prevalence varies between 0.1/100,000 and 0.4/100,000. Familial occurrence of thymoma is very rare. We studied a family bearing the constitutional chromosome translocation t(14;20)(q24;p12), 3 of whose members had a thymoma. In this family, among 27 patients, 11 had the translocation: 3 had thymoma and 4 others had 5 different autoimmune diseases: type 1 diabetes mellitus, Graves' disease, pernicious anemia, primitive Sjögren disease, and autoimmune pancytopenia. FISH studies allowed us to be more specific about the translocation breakpoints. The 14q24 breakpoint was in intron 5 of RAD51L1, and the 20p12 breakpoint was 100 kb telomeric to BMP2. RAD51L1 is a tumor-suppressor gene belonging to the RAD51 family, already implicated in many tumors (uterine leiomyomas, pseudo-Meigs syndromes, pulmonary chondroid hamartomas) and involved in recombinational repair of DNA double-strand breaks. BMP2 belongs to the TGFbeta superfamily, and the BMP2-BMP4 genes are involved in thymocyte differentiation by blocking progression from CD4-CD8- to CD4+CD8+ while maintaining a sufficient pool of immature precursors. Dysregulation of RAD51L1 and/or BMP2 may explain this familial occurrence of thymomas and autoimmune diseases. Using QRT-PCR, we studied the expression of BMP2 in 20 sporadic thymomas and found various levels of expression that may be associated with autoimmune diseases.
Autoimmune Diseases↗
Pressure effects for crystal growth in a closed system.
We analyze the growth of a crystal from its supercooled liquid in a closed domain (constrained growth), taking into account the effects due to the different densities rho(s) and rho(l) of the solid and liquid phases. We assume rho(l) > rho(s), i.e., the liquid expands upon solidification. Then, the growth is contrasted by an increasing pressure, which results in a continuous decrease of the coexistence temperature and the effective supercooling. These phenomena have been simulated in two dimensions through a modified version of the classic phase-field model. We observe that for spherical growth the interface temperature reflects almost instantaneously the change of the coexistence temperature. For dendritic growth, we observed a relaxation time for the dendrite tip velocity and the tip radius which is comparable to the characteristic time of the process; however, after the first fast transient, the growth dynamics seems to follow the changing pressure with no appreciable lag. The onset of the morphological instability is slightly anticipated in respect to free growth.
Journal Article↗
Scaling anomalies in the coarsening dynamics of fractal viscous fingering patterns.
We analyze a recent experiment of Sharon et al. (2003) on the coarsening, due to surface tension, of fractal viscous fingering patterns (FVFPs) grown in a radial Hele-Shaw cell. We argue that an unforced Hele-Shaw model, a natural model for that experiment, belongs to the same universality class as model B of phase ordering. Two series of numerical simulations with model B are performed, with the FVFPs grown in the experiment and with diffusion limited aggregates as the initial conditions. We observed Lifshitz-Slyozov scaling t(1/3) at intermediate distances and slow convergence to this scaling at small distances. Dynamic scale invariance breaks down at large distances.
Journal Article↗
Advection flow effects in the growth of a free dendrite.
The growth of a free dendrite into a supercooled liquid is simulated through a modified version of the phase-field model, which takes into account the advection flow due to the different densities rho(s) and rho(l) of the solid and liquid phases. The intensity of the flow is maximal at the dendrite tip and decays far from the surface of the crystal. At fixed undercooling, as the density ratio rho(s)/rho(l) increases, we observe a decrease of the tip velocity, while the tip radius increases. The Peclet number is shifted with respect to the pure diffusive value. The onset of the morphological instability, which is responsible for the origin of the dendrite from a growing circular germ, is slightly anticipated by the flow effects.
Journal Article↗
Simulating coarsening dynamics of fractal clusters.
Explore the source record for details and available documents.
Journal Article↗
Interface dynamics and solute trapping in alloy solidification with density change.
We present a phase-field model for the solidification of a binary alloy, which incorporates hydrodynamic effects due to the different densities of the solid and liquid phases. We start from a generalized thermodynamic potential with squared gradient terms for the associated fields; the condition of local positive entropy production is then utilized to derive a set of equations that drive the system towards equilibrium. The model has been numerically solved in one dimension, to investigate the effects of the flow field on the interface dynamics. We observed that solute trapping is almost unaffected by the fluid advection, while the interface mobility is strongly reduced as the fluid velocity increases. This reflects on the dependence of the interface temperature T(I) on the growth rate v(I): the region of the unstable (ascending) branch is reduced, and the maximum of the T(I)(v(I)) curve is shifted towards lower velocities.
Journal Article↗
Tilt-table test during transcranial Doppler monitoring in Parkinson's disease.
Cardiovascular autonomic dysfunction can occur in Parkinson's disease (PD) and intracranial vascular modifications following orthostatism may be relevant to diagnostic and therapeutic decision-making. We performed transcranial Doppler monitoring of right middle cerebral artery (MCA) at rest and during passive 70 degrees tilt in 19 patients with idiopathic PD and in 19 age-matched normal controls. Brachial arterial blood pressure (systolic, diastolic and mean), cardiac frequency (CF), respiratory frequency and mean velocity (MV) of the MCA were recorded after 10 min of rest in supine position, and each minute during 9 min of tilting and 5 min of restored clinostatic position. The pulsatility and cerebrovascular resistances (CVR) indexes were calculated. At rest there was no significant difference in blood pressure, CF, respiratory frequency and MCA mean velocity between patients and controls. During tilt test, PD patients showed a trend to higher pulsatility index values (p=0.09) and significant lower diastolic blood pressure (p=0.001), while there was no significant difference in CVR index. In conclusion, PD patients showed mild hypotensive response to orthostatic stress, with intracranial compensatory vasodilation. Our findings suggest a preserved intracerebral autoregulation in PD without symptoms of orthostatic intolerance.
Aged↗
Phase ordering with a global conservation law: Ostwald ripening and coalescence.
Globally conserved phase ordering dynamics is investigated in systems with short range correlations at t=0. A Ginzburg-Landau equation with a global conservation law is employed as the phase field model. The conditions are found under which the sharp-interface limit of this equation is reducible to the area-preserving motion by curvature. Numerical simulations show that, for both critical and off-critical quench, the equal-time pair correlation function exhibits dynamic scaling, and the characteristic coarsening length obeys l(t) approximately t(1/2). For the critical quench, our results are in excellent agreement with earlier results. For off-critical quench (Ostwald ripening) we investigate the dynamics of the size distribution function of the minority phase domains. The simulations show that, at large times, this distribution function has a self-similar form with growth exponent 1/2. The scaled distribution, however, strongly differs from the classical Wagner distribution. We attribute this difference to coalescence of domains. A theory of Ostwald ripening is developed that takes into account binary coalescence events. The theoretical scaled distribution function agrees well with that obtained in the simulations.
Journal Article↗
Uncommon complications during chest tube placement.
Explore the source record for details and available documents.
Adult↗