A data-driven model-free adaptive controller with application to wind turbines.

A data-driven controller is presented in this paper, which stems from the well known model-free adaptive control approach based on an equivalent linearized dynamical model of the plant. Inspired by the recent paper (Liu and Yang, 2019), the output tracking problem is here solved by a data-driven adaptive sliding-mode controller simultaneously ensuring prescribed performance constraints. To allow a rigorous stability analysis, the sliding variable, and the consequently derived controller, have been redesigned with respect to the inspiring paper. A proper setting of the gain of the discontinuous term is shown necessary to ensure closed loop stability. Validation of the technique has been extensively performed on the well assessed high-fidelity tool FAST (NREL) to solve the efficiency maximization problem using the proposed approach for a 5 MW wind turbine operating in the medium wind speed region.

Impact of diabetes on COVID-19-related in-hospital mortality: a retrospective study from Northern Italy.

PURPOSE: The purpose of this study was to evaluate the impact of pre-existing diabetes on in-hospital mortality in patients admitted for Coronavirus Disease 2019 (COVID-19). METHODS: This is a single center, retrospective study conducted at Policlinico di Monza hospital, located in the Lombardy region, Northern Italy. We reviewed medical records of 373 consecutive adult patients who were hospitalized with COVID-19 between February 22 and May 15, 2020. Data were collected on diabetes status, comorbid conditions and laboratory findings. Multivariable logistic regression was performed to evaluate the effect of diabetes on in-hospital mortality after adjustment for potential confounding variables. RESULTS: Mean age of the patients was 72 ± 14 years (range 17-98), 244 (65.4%) were male and 69 (18.5%) had diabetes. The most common comorbid conditions were hypertension (237 [64.8%]), cardiovascular disease (140 [37.7%]) and malignant neoplasms (50 [13.6%]). In-hospital death occurred in 142 (38.0%) patients. In the multivariable model older age (Relative Risk [RR] 1.06 [1.04-1. 09] per year), diabetes (RR 1.56 [1.05-2.02]), chronic obstructive pulmonary disease (RR 1.82 [1.13-2.35]), higher values of lactic dehydrogenase and C-reactive protein were independently associated with in-hospital mortality. CONCLUSION: In this retrospective single-center study, diabetes was independently associated with a higher in-hospital mortality. More intensive surveillance of patients with this condition is to be warranted.

Pitch angle control of a wind turbine operating above the rated wind speed: A sliding mode control approach.

The paper focuses on variable-rotor-speed/variable-blade-pitch wind turbines operating in the region of high wind speeds, where control is aimed at limiting the turbine energy capture to the rated power value. A robust sliding mode approach is proposed, using the blade pitch as control input, in order to regulate the rotor speed to a fixed rated value, in the presence of uncertainties characterizing the wind turbine model. Closed loop convergence of the overall control system is proved. The proposed control solution has been validated on a 5-MW three-blade wind turbine using the National Renewable Energy Laboratory (NREL) wind turbine simulator FAST (Fatigue, Aerodynamics, Structures, and Turbulence) code. A comparison with the standard FAST baseline controller (NWTC 2012 and Jonkman et al. 2009) has been also included.

Controversies about induction therapy.

Induction therapy refers to the initiation of intense immunosuppression in the initial days after transplantation when the recipient's immune system contacts donor antigens for the first time. Induction therapy may also be used to permit delayed initiation of calcineurin inhibitors (CNIs) for maintenance immunosuppression among patients with significant renal failure (RF). The rationale of its use is to provide intensive immunosuppression at the time when the alloimmune response is most intense. In general, induction therapy can be divided into 2 categories: depleting antibodies (eg, polyclonal antibodies [horse or rabbit antithymocyte globulin], anti-CD3 antibodies [OKT3], and human monoclonal anti-CD52 [alentuzumab]) and nondepleting antibodies (eg, anti-CD25 antibodies [daclizumab, basiliximab] or fusion proteins with natural binding properties currently being studied, eg, CTLA4-Ig [belatacept]). The advantages and disadvantages of induction therapy are discussed.

Incidence of neoplastic disease following lung transplantation: a 17-year single-center experience.

OBJECTIVE: Chronic immunosuppressive therapy following solid organ transplantation has been correlated with an increased risk of posttransplantation neoplastic disease (PTND). In this study we evaluated PTND incidence and outcome at our institution over a 17-year period among patients receiving lung transplantation. MATERIALS AND METHODS: Between February 1992 and December 2008, we performed 290 lung transplantations in 280 patients, including 139 single (48% with 5 retransplantations), and 151 double lung transplantations (52% with 5 retransplantations). Among the 280 patients, 2 had undergone previous double lung transplantation in other hospitals. Follow-up of transplant recipients was performed up to December 2009. RESULTS: Forty-two patients died in the hospital, producing a cumulative early (30-day) mortality rate of 15%. Among the 238 patients discharged from the hospital who entered our follow-up program, 36 (15%) experienced PTND. The mean time between transplantation and diagnosis was 47 ± 42 months, and patients' mean age at time of diagnosis was 55 ± 14 years. Overall freedom from PTND was 97%, 84%, and 73% at 1, 5, and 10 years, respectively. PTND was considered to be the direct cause of death in 11 patients (30%). Overall survival of patients with PTND at five years (45%) did not differ from the remainder of the transplanted population (46%). However, PTND became a relevant cause of death in the long-term (>5 years) follow-up. CONCLUSION: Our experience confirms that PTND was frequently diagnosed following lung transplantation. Even if PTND did not seem to significantly affect the survival of patients undergoing lung transplantation, it may become a significant cause of death among those surviving beyond 5 years.

[Calcineurin inhibitors and mechanisms that are responsible for the appearance of post-transplant diabetes mellitus]. / Inibitori della calcineurina e meccanismi di insorgenza di diabete mellito post-trapianto.

Calcineurin (CaN), a calmodulin-dependent heterodimer, is, together with NAF-T, involved in the regulation of the Ca++ pump and in the transmission of the activation signal of the immune response. The CaN inhibitor drugs, such as cyclosporin A (CyA), carried by cyclophillin, and tacrolimus, carried by FK-binding protein-12 (FKBP-12), inhibit the binding with the regulatory subunit CaNB. A meta-analysis, comparing tacrolimus with cyclosporin A, has evidenced that tacrolimus significantly increases the diabetes prevalence one year after renal transplant. The diabetogenic effect is due to a direct effect of both drugs on the beta pancreatic cell, in particular on intracellular Ca++ metabolism, which is involved in the insulin secretion and in the reduction of the number of the secretor granules. Some immunological-hystochemical studies, performed on murine pancreas, have evidenced that the FKBP-12 content is higher in beta cells than in alpha cells. This fact allows a high intracellular store of tacrolimus, and a consequently more toxic effect, inside the insulin secreting structures. On the contrary, the low FKBP-12 content of alpha cells involves a higher content of calcineurin and a higher resistance to toxic effects. Finally, an increased incidence of islet cell antibodies (ICA) has been evidenced in patients treated with tacrolimus, as opposed to those treated with CyA.

Neoplastic disease after heart transplantation: single center experience.

OBJECTIVES: Mandatory use of prolonged immunosuppression in organ transplantation is complicated by an increased incidence of cancer. The current study represents a retrospective analysis of the incidence of neoplasms in our heart transplantation program. METHODS: Four-hundred and seventy-four patients (403 male and 71 female; mean age, 48.6+/-12.1 years), with at least 30 days of follow-up, were enrolled in this study. Patients received triple immunosuppression with cyclosporin A, azathioprine and steroids. Moreover, as a prophylactic anti-lymphocyte therapy, 388 patients (82%) were administered RATG, 67 patients (14%) received ALG and 19 patients (4%) OKT3. The mean follow-up time was 71.1+/-43.0 months. RESULTS: Fifty-five patients (11.6%) developed malignant neoplasms. The cancer frequencies were: solid tumors, 55%; non-Hodgkin lymphomas (NHL), 20%; Kaposi's sarcomas, 11%; skin cancers, 9%; undifferentiated sarcomas and myelomas, 5%. Solid tumors mainly affected the lung (39%), bowel (16%), stomach (6.5%), liver (6.5%), pancreas (6.5%) and oral cavity (6.5%). The times to the onset of cancer from transplantation were: Kaposi's sarcoma, 12.7+/-16.8 months; skin cancers, 34.5+/-23.8 months; solid tumors, 54.3+/-38.7 months; NHL, 60.1+/-36.4 months; undifferentiated sarcomas and myelomas, 90.0+/-15.6 months. As determined by univariate and multivariate analyses, sex, number of treated rejections, previous history of tumor, average dose of cyclosporine and prednisone and cyclosporine blood levels did not increase the incidence of malignancies. Univariate analysis suggests a significant correlation between the type of prophylactic immunoglobulins and the average dose of azathioprine with the incidence of neoplasms. Both univariate and multivariate analyses demonstrated a significant correlation between patient's age at the time of transplantation and risk of cancer occurrence (risk increased by 1.074/year; P=0.0056 with multivariate Cox regression). CONCLUSIONS: Cancer is a strong limitation for long-term survival after heart transplantation. The only risk factor recognized is the patient's age at the time of transplant. Furthermore, the type of prophylactic globulins used for induction therapy and some specific immunosuppressant agent (azathioprine) may play a significant role in the development of malignancies after transplantation.

Fetal erythroblast isolation up to purity from cord blood and their culture in vitro.

BACKGROUND: Erythroblasts have been the most encouraging candidate cell type for noninvasive prenatal genetic investigation. We previously showed that human erythroblasts can be recovered from bone marrow and blood bank buffy coats by a physical cell separation. In the present study, we modified our previous methodology, taking into account the peculiar behavior of erythroblasts in response to modifications of pH and osmolality of the separation medium. METHODS: Twenty to forty milliters of cord blood were initially centrifuged on Ficoll/diatrizoate (1.085 g/ml). The interphase cells were further separated on a continuous density gradient (1.040-1.085 g/ml). Two different gradients were initially compared: the first was iso-osmolar and neutral, whereas the second also contained an ionic strength gradient and a pH gradient (triple gradient). A subsequent monocyte depletion was performed by using magnetic microbeads coated with anti-CD14 monoclonal antibody (mAb), and erythroblasts were purified by sedimentation velocity. Purified cells were investigated by analyses with fluorescence-activated cell sorting (FACS) and fluorescence in situ hybridization (FISH) and immunocytochemistry with mAb against fetal hemoglobin and were cultured in vitro. RESULTS: When nucleated cells were spun on an iso-osmolar and neutral continuous density gradient, two separated bands of nucleated red blood cells (NRBCs) were obtained: a light fraction banding at 1.062 g/ml and an heavy fraction banding at 1.078 g/ml. Conversely, when cells were spun in the triple gradient, NRBCs were shifted to the low-density region. Monocyte depletion by immunomagnetic microbeads and velocity sedimentation provided a pure erythroblast population. FACS and FISH analyses and immunocytochemistry substantiated the purity of the isolated cell fraction, which was successfully cultured in vitro. CONCLUSIONS: We have shown that fetal erythroblasts can be purified up to homogeneity from cord blood, but further refinements of the isolation procedure are necessary before the same results can be obtained from maternal peripheral blood.

Bone marrow changes in heart transplant recipients with peripheral cytopenia.

BACKGROUND: We analyzed bone marrow changes in heart transplant recipients who develop peripheral cytopenia and underwent bone marrow biopsy (BMB). We correlated the changes in bone marrow with survival, acute and chronic rejection, infections, and malignancy. METHODS: The test group was constituted of 64 heart transplant recipients with peripheral cytopenia, in whom 82 BMBs were performed to assess marrow quantitative (cellularity, erythropoiesis, myelopoiesis, megakaryopoiesis, fibrosis, and blast cells) and qualitative (dyserythropoiesis, dysmyelopoiesis, and dysmegakaryopoiesis) changes. The control series was constituted of 217 matchable transplant recipients without cytopenia. Statistical analysis was aimed at assessing whether: (1) cytopenia is an independent risk factor for survival; (2) acute rejection, chronic rejection, infections, and malignancy predict cytopenia; (3) the degree in BMB change allows further stratification of the risk of death; and (4) characteristics and distribution of BMB lesions vary in patients with and without acute and chronic rejection, infections, and malignancy. RESULTS: In the test group, BMB specimens showed reduced cellularity in 68% of patients and dysplastic changes of a mild degree affecting all three marrow lines (erythropoietic in 88%, myelopoietic in 43%, and megakaryopoietic in 79%). At statistical analysis, peripheral cytopenia was an independent risk factor for survival, and malignancy proved to be a risk factor for cytopenia. Of BMB specimen changes, only dysmegakaryopoiesis showed a trend as a negative risk factor for survival. Acute rejection was associated with a high score of erythropoiesis, infections with a low score of dysmegakaryopoiesis, and malignancy with a high score of cellularity. CONCLUSIONS: Peripheral cytopenia is an independent risk factor for survival in heart transplant recipients. Different marrow changes correlate with transplantation-related complications, i.e., acute rejection, infection, and malignancy.

Cyclosporin-A in severe refractory anemia of myelofibrosis with myeloid metaplasia: a preliminary report.

BACKGROUND AND OBJECTIVE: Severe anemia is the outstanding problem in approximately 50 percent of patients with myelofibrosis with myeloid metaplasia (MMM). The present trial was based on the considerations that abnormal immune responses are frequently associated with MMM and that cyclosporin A (Cy-A) has proven to be effective in improving anemia in autoimmune disorders. The aim of this study was to evaluate the effect of Cy-A on anemia of MMM. DESIGN AND METHODS: We studied 10 patients with MMM and severe anemia who were not responsive to corticosteroids. Eight of them showed evidence of immune defects (direct or indirect Coombs' test, antinuclear or antimitochondrial antibodies, circulating immune complexes). Cy-A was delivered orally in two refracted doses of 5 mg per kilogram bw every day and the serum level of the drug was maintained between 100 and 200 ng/mL for at least 6 months. Clinical effects were measured by calculating a normalized transfusional need (NTN), and response was defined as about a 30% reduction in the initial transfusion requirement. Hematologic parameters, s-Epo, s-TfR, s-IL2R and lymphocyte flow cytometric analysis were also evaluated. The results were analyzed with the Student's t-test. RESULTS: Only 6 patients completed the entire 6 months of planned therapy. Three of these responded, with one no longer needing transfusions. A high CD4/CD8 ratio was predictive of response (mean value 4.7 +/- 3.5 in responders versus 0.9 +/- 0.4 in non-responders, p = 0.06). INTERPRETATION AND CONCLUSIONS: An immunomediated mechanism negatively affects erythropoiesis in MMM. Cy-A may be effective for patients with severe refractory anemia in this disease.

FK506 effectiveness in reducing acute rejection after heart transplantation: a prospective randomized study.

BACKGROUND: Tacrolimus (FK506) has recently become available clinically as an alternative to cyclosporine-based immunosuppression. This study reports the middle-term results of a prospective, randomized trial that compared FK506 with cyclosporine-based immunosuppression in heart transplant recipients. METHODS: Twenty-five consecutive patients were randomized at a 2:1 ratio into two groups, one of which received FK506 (15 patients), the other cyclosporine (10 patients). Both groups received similar concomitant immunosuppression. The patients were followed up for 12 months. The following outcome parameters were analyzed: survival, rejection and infection rate, lymphocyte subsets, new-onset diabetes, renal and hepatic function, hypertension, right-sided heart catheterization data, graft coronary artery disease, and neurologic side effects. RESULTS: The mortality rate (two patients) in the FK506 group was 13% versus 0% in the cyclosporine group (p = NS). The two deaths were the consequences of early infections and higher doses of FK506. From the outset, the FK506 group presented a lower prevalence of acute rejection, a lower requirement for rejection treatments and a higher incidence of infections. Accordingly, we reduced overall immunosuppression for the last seven patients in the FK506 group; the decrease in FK506 and prednisone dosage led to a decrease in the early infection rate without an increase in the rejection rate. There was no difference between the two groups in diabetes incidence, renal and hepatic function, right-sided heart catheterization data, or coronary angiograms. Hypertension was less frequent and milder in the FK506 group. CONCLUSIONS: This experience suggests that FK506 can be safely used in heart transplantation. It can decrease the frequency of rejection episodes. Low-dose administration allows a lower infection rate without an increase in rejection. With a protocol of delayed starting and low dosing, side effects such as renal toxicity, hypertension, and neurologic toxicity seem to be unlikely. Further studies are needed to establish the exact dosage and therapeutic levels of the drug.

Factors increasing the risk of allograft vascular disease in heart transplant recipients.

Allograft vascular disease is the major cause of late cardiac graft failure. A multifactorial etiopathogenesis is supposed. Our study investigated factors associated with allograft vascular disease occurrence. After stratifying our series on the basis of potential risk factors, we calculated allograft vascular disease incidence rate in 267 grafts from 258 patients who underwent transplant between November 1985 and August 1996. Chi-square test was used for the identification of univariate risk factors to be included in a multivariate model. Multivariate analysis was based on a Poisson model. Seventy of the 267 grafts (26.2%) were diagnosed with allograft vascular disease. Heart disease other than idiopathic dilated cardiomyopathy, donor's age, number of mismatches for HLA-B = 2, presence of systo-diastolic hypertension, number of acute rejection positive endomyocardial biopsies > or = 7 and the association of human Cytomegalovirus and hepatitis C virus infections proved to be univariate risk factors, and were included in the Poisson multivariate model. The association of Cytomegalovirus and hepatitis C infections multiplied allograft vascular disease incidence rate by 3.9, systo-diastolic hypertension by 2.2, occurrence of 2 HLA-B mismatches by 2, a high number (> or = 7) of acute rejection positive-endomyocardial biopsies by 1.8, and heart disease other than idiopathic dilated cardiomyopathy by 1.8. The association of human Cytomegalovirus and hepatitis C virus infections, of HLA-B mismatches, of acute rejection-positive endomyocardial biopsies, as well as post-transplantation hypertension and native heart disease other than idiopathic dilated cardiomyopathy, proved to be positively associated with an increased risk of allograft vascular disease. Given the concordance of our data with those of numerous prior series, we are going to adopt a special surveillance angiographic protocol for patients with these factors.

Membrane CD22 defines circulating myeloma-related cells as mature or later B cells.

Circulating clonally related earlier cells are present in multiple myeloma (MM) and may be involved in the dissemination of this disease, its recurrence, and chemoresistance. The nature, stage of differentiation, and size of this cell population remain uncertain. Unlike other B-cell markers, CD22 membrane expression is limited to the late differentiation stages comprised between mature B cells (CD22+) and plasma cells (PC; CD22-) and may thus be useful in delimiting the maturational state of circulating early myeloma cells. Peripheral blood clone-related cells were detected by anti-idiotypic (Id) monoclonal antibodies and found to express CD22 (92% to 95%), monotypic light and heavy chain (100%), and CD38 (45%), whereas bone marrow PC were CD22-negative. CD22 expression was also documented on functional myeloma PC precursors, defined as peripheral blood cells capable of in vitro cytokine-driven monotypic PC differentiation, because up to approximately 70% inhibition of this process was obtained in 10 myeloma patients through the use of biospecific antibodies (BsAb) that deliver the plant toxin saporin to CD22+ cells. As further evidence of CD22 on circulating abnormal cells, it was found that in the only patient analyzed for DNA content, a portion of the peripheral blood CD22+ cells killed were hyperdiploid. Collectively, these findings indicate that most peripheral blood myeloma PC precursors are mature or later B cells presenting membrane CD22. The pattern of CD22 expression suggests the existence in MM of a differentiation process analogous to the normal antigenic response, in which CD22+ B cells migrate to the bone marrow and lose CD22 with PC differentiation. In addition, the sensitivity of myeloma PC precursors to the cytotoxic effects of the anti-CD22 BsAb and the possibility of interfering with their differentiation have potential therapeutic relevance.

Response to cyclosporin A and rhG-CSF in a case of aplastic anemia.

A 23-year-old male patient developed aplastic anemia and was treated with cyclosporin A and rhG-CSF. Bone marrow biopsy showed an improvement in cellularity with a recovery of all hematopoietic precursors after nine weeks of therapy. WBC increased after two weeks of treatment, mostly due to an increase in the absolute granulocyte cell count. Hb, RBC, Plts and reticulocytes showed an increase six weeks after the beginning of therapy. Of the serum cytokines, EPO levels progressively decreased, while sTfR increased in peripheral blood. A reverse correlation between blood neutrophil count and serum levels of G-CSF was observed, indicating an increased clearance of G-CSF. Finally, sIL-2R showed a rapid increase in the first week of treatment and prior to the increase in PMN cells. Thus, the use of cyclosporin A and rhG-CSF in our patient induced a complete recovery of hemopoiesis, and this may be explained by a synergic effect induced by the capacity of cyclosporin A to remove inhibitory factors and the stimulatory activity of rhG-CSF.

AL amyloidosis. Characterization of amyloidogenic cells by anti-idiotypic monoclonal antibodies.

BACKGROUND: AL amyloidosis is characterized by systemic tissue deposition of monoclonal Ig light chains synthesized by a bone marrow plasma cell (PC) clone whose biologic characteristics remain undetermined. EXPERIMENTAL DESIGN: Anti-idiotypic (anti-Id) monoclonal antibodies (MoAbs) were used as specific probes to identify and study amyloidogenic cells in two patients by means of immunofluorescence methods. These MoAbs recognized populations of bone marrow pre-PC, PC, and peripheral blood lymphocytes. To test whether the circulating Id+ lymphocytes were capable of PC differentiation, peripheral blood lymphocytes were incubated with the differentiation-inducing agents, interleukin-3 and interleukin-6 in liquid culture. Preincubation with the anti-Id MoAb and complement was used to inhibit formation of Id+PC in vitro. RESULTS: The anti-Id MoAb identified three types of cells in the bone marrow with cytoplasmic Ig having the same isotype as the monoclonal component: a) lymphoid cells, that were slightly larger than common peripheral blood lymphocytes (47% CD45RA+, 28% CD45R0+, 97% CD38-, 100% CD10-, 100% mu-chain-); b) lymphoplasmacytoid cells with more abundant cytoplasm and Id+ Ig (CD45RA-, CD45RO-, CD10-, 53% CD38+); 3) mature PC that were very similar to normal PC in morphology and antigenic profile (CD38+, PCA1+, CD56-). A different picture was seen when anti-Id MoAb were used to detect peripheral blood Id+ elements: analysis revealed a population of mature resting surface Ig+ B lymphocytes. Circulating Id+ lymphocytes differentiated in vitro to PC and lymphoplasmacytoid cells that were very similar to those present in the bone marrow. A significant reduction in the number of Id+ PC was obtained after incubation with the anti-Id MoAb and complement. CONCLUSIONS: This study shows that the amyloidogenic cell clone is constituted by at least the following cell populations: a fraction of bone marrow cells (lymphoid, lymphoplasmacytoid cells and PC) and a subset of peripheral blood post-switched B lymphocytes. The results suggest a relationship among these cells, indicating that circulating Id+ lymphocytes may be the possible precursors of the more differentiated bone marrow population.