To compare pulmonary emboli resulting from pulse-spray pharmacomechanical thrombolysis (PSPMT) and mechanical thrombolysis performed to declot dialysis-access grafts.
Polytetrafluoroethylene ...arteriovenous shunts were created in eight dogs and were deliberately clotted at monthly intervals. Animals were randomly assigned to treatment with pulse-spray urokinase thrombolysis or a low-speed rotational percutaneous thrombolytic device. Perfusion imaging, pulmonary-artery pressure measurements, and pulmonary arteriography were performed before and after each procedure.
A total of 22 procedures were performed (11 PSPMT and 11 mechanical thrombolysis). Declotting was successful in all procedures, with 100% 30-day patency. Segmental defects were seen on perfusion images after 10 (91%) of 11 PSPMT procedures and two (18%) of 11 mechanical thrombolysis procedures (P < .002). Transient increases in pulmonary-artery pressure occurred in the PSPMT group. Complete resolution of emboli and return to baseline pressures were seen in all cases, even after multiple (up to four) procedures in the same animal. There was no histologic evidence of pulmonary infarction in either group.
The percutaneous thrombolytic device is effective for declotting dialysis grafts in dogs and results in statistically significantly fewer pulmonary emboli compared with PSPMT.
Background/aims: Skin cancer diagnosis depends, to a great extent, on visual inspection and histopathological examination of excised tissues. The aim of this study is to evaluate the ability of ...electrical impedance scanning to differentiate between benign and malignant skin lesions.
Methods: A preclinical study was conducted on 40 nude mice injected subcutaneously with a human melanoma strain. Impedance measurements were recorded every week to correlate electrical changes with tumor growth and histological findings. A clinical study was also performed on 178 human suspicious skin lesions before excision. The impedance measurements were correlated to the histopathological results.
Results: Normalized conductivity and capacitance, recorded on growing skin tumors in nude mice, were shown to change relative to lesion size. Necrosis, present in most of the larger lesions, was associated with a decrease in the electrical conductivity. Similar electrical parameters were used to classify human melanoma lesions with 92% sensitivity and 67% specificity. In addition, four out of five BCC lesions were correctly diagnosed. Moreover, dysplastic lesions were diagnosed with 91% sensitivity and 59% specificity. For comparison, physicians diagnosed melanoma lesions with 75% sensitivity and 87% specificity and dysplastic lesions with 46% sensitivity and 80% specificity.
Conclusions: The animal study showed that electrical impedance measurements reflect morphological changes related to the growth of a cancerous skin lesion. These findings are in agreement with a preliminary clinical study. Electrical Impedance Scanning can therefore be considered as an objective and non‐invasive tool for differentiation between benign and malignant skin lesions.
Chronic idiopathic thrombocytopenic purpura is an autoimmune disorder in which the destruction of autologous platelets is mediated by autoantibodies directed against platelet-surface constituents.
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...Glycoproteins IIb and IIIa, which exist in the platelet membrane in a 1:1 complex (IIb-IIIa), appear to be the main target molecules for these autoantibodies.
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The destruction of autologous platelets is thought to result from the ingestion of autoantibody-coated platelets by phagocytic cells in the spleen and other organs.
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The functional state of the reticuloendothelial system may influence the rate of cell destruction in individual patients.
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We recently encountered a patient who had severe, life-threatening thrombocytopenia after . . .
To establish the safety and efficacy of the Arrow Trerotola mechanical percutaneous thrombolytic device (PTD) for restoring patency of thrombosed hemodialysis grafts.
The hindlimb model of dialysis ...grafts was created in six dogs. Animals had either unilateral (n = 4) or bilateral (n = 2) polytetrafluoroethylene grafts, totaling eight grafts. Grafts were deliberately clotted 48 hours before thrombolysis. Thrombolysis was performed with five different versions of the PTD constructed of stainless steel (n = 12) or nitinol (n = 26) and rotated with use of a hand-held motor drive. After thrombolysis, fistulography was performed.
Thirty-eight procedures were performed with the PTD, with 100% success. Thirty-day patency, evaluated in a subset of 15 procedures, was 100%. Complications included a single arterial embolus (2.6%) and eight device breakages (21%, all but two with the stainless steel version); none had any clinical consequences. A final modification of the nitinol device yielded 11 consecutive procedures without further breakage. No residual thrombus occurred in any procedure. Pathologic examination showed no significant injury to the vessels or neointima.
The PTD is highly effective for mechanical thrombolysis in an animal model of clotted dialysis grafts. Based on this animal model, the device appears safe in its final modified form.
Cystic fibrosis, a common indication for lung transplantation, is an uncommon indication for liver transplantation. Cystic fibrosis results in cirrhosis in about 30% of patients. The biliary type of ...cirrhosis is characterized by fibrosis; bile duct proliferation; and, in some cases, accumulation of eosinophilic PAS-positive, diastase-resistant material in the interlobular ducts. The cirrhosis is hypothesized to result from production of lithogenic bile resulting from excessive loss of bile acids. With improvement in pulmonary care, some patients have progressed to liver failure requiring transplantation while maintaining normal pulmonary function. The results of liver transplantation in these patients are generally good with no apparent increase in morbidity. With the exception of one patient, all the reported cases of liver transplantation for cystic fibrosis have used cyclosporine (CsA) as part of the immunosuppressive protocol. The present formulation of CsA, Sandimmune, is in an olive or corn oil base. The absorption of CsA after an oral dose of Sandimmune is dependent on multiple factors, including biliary and pancreatic secretions, that are necessary to digest and emulsify the preparation. With impaired pancreatic exocrine function in cystic fibrosis, CsA absorption would be affected. Reported cases of liver transplantation in patients with cystic fibrosis have demonstrated the need for higher doses of Sandimmune to achieve adequate therapeutic CsA blood levels. A new formulation of CsA, Neoral, has recently been marketed in Europe and is under investigation in the United States. Neoral is a microemulsion containing cremophor RH40, propylene glycol, and dl- alpha -tocopherol, which act as surfactants and both lipophilic and hydrophilic solvent. The droplet size is between 10 and 100 nm in diameter. Neoral disperses upon contact with aqueous solvents independent of biliary and pancreatic secretion. In randomized trials in stable renal transplant recipients these characteristics have resulted in a higher maximum concentration (Cmax) at an earlier time (Tmax), a greater area under the concentration curve (AUC) and less inter- and intrapatient variability when compared with Sandimmune. Based on these results, a compassionate use protocol providing Neoral to solid organ transplant recipients who require high doses of Sandimmune to achieve adequate CsA trough blood levels was designed. We report here a pediatric liver transplant recipient with cystic fibrosis and poor cyclosporine absorption, who was enrolled in that trial, and who demonstrated a dramatic increase in the absorption of cyclosporine following conversion to Neoral.
Blow-up on the boundary for the heat equation Fila, Marek; Filo, Ján; Lieberman, Gary M.
Calculus of variations and partial differential equations,
1/2000, Letnik:
10, Številka:
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Journal Article
The scope of most high-level synthesis efforts to date has been at the level of a single behavioral model represented as a control/data-flow graph. The communication between concurrently executing ...processes and its requirements in terms of timing and resources have largely been neglected. This restriction limits the applicability of most existing approaches for complex system designs. This paper describes a methodology for the synthesis of interfaces in concurrent systems under detailed timing constraints. The authors model interprocess communication using blocking and nonblocking messages. They show how the relationship between messages over time can be abstracted as a constraint graph that can be extracted and used during synthesis. They describe a novel technique called interface matching that minimizes the interface cost by scheduling each process with respect to timing information of other processes communicating with it. By scheduling the completion of operations, some blocking communication can be converted to nonblocking while ensuring the communication remains valid. To further reduce hardware costs, the authors describe the synthesis of interfaces on shared physical media. They show how this sharing can be increased through rescheduling and serialization of the communication. In addition to systematically reducing the interface synchronization cost, this approach permits analysis on the timing consistency of interprocess communication.< >
This report summarizes the results after two years of a continuing prospective study of cadaver donor renal transplantation being conducted by the Southeastern Organ Procurement Foundation (SEOPF). ...Data are presented on 942 first grafts. Blood transfusions were found to be a major (if not the major) determinant of allograft survival. HLA-A and -B matching was of significant value and the effect of compatibility became more significant as time passed. ALS provided for better long-term survival of more compatible grafts and better short-term survival of more incompatible grafts, but it was not a “safer” immunosuppressant. Autogenous nephrectomy appeared to aid in the survival of more imcompatible allografts, but not more compatible allografts. Kidneys obtained and implanted locally and kidneys obtained at one center and implanted at another had the same incidence of acute tubular necrosis (ATN) as well as the same patient and graft survival. Preservation time did not relate to ATN, patient survival, or graft survival (within the limits of the study); however, ATN did adversely affect graft survival. The final systolic pressure of the perfusion pump was the only perfusion characteristic which predicted ATN. Race, sex, pregnancy, and duration of dialysis did not correlate with graft survival if the effects of transfusions and compatibility were controlled.
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