State and output feedback design for robust tracking of linear systems with rate limited actuators

A design technique (Control of Uncertain Systems with Bounded Inputs, Tarbouriech S, Garcia G, (Eds), Lecture Notes in Control and Information Sciences, vol. 227 , Springer: Berlin, 1997; 173–186) recently proposed for stabilization of a linear system with rate‐limited actuators is utilized to design feedback laws that cause the system output to track a desired command signal. This design technique combines two design techniques recently developed for linear systems with position limited actuators, piecewise‐linear LQ control (Automatica, 1994; 30 : 403–416) and low‐and‐high gain feedback (IEEE Trans. Automat. Control, 1996; 41 : 368–378), and hence takes advantage of both design techniques, while avoiding their disadvantages. In the case that only the output is available for feedback, the performance of the state feedback law is preserved by the use of a fast observer. An open‐loop exponentially unstable fighter aircraft is used to demonstrate the effectiveness of the proposed control design method. Copyright © 2002 John Wiley & Sons, Ltd.     

In vivo 23Na NMR studies of myotonic dystrophy

Myotonic dystrophy is an inherited multi-system disease. Its pathophysiology leading to muscle malfunction and damage is not well understood. ²³Na NMR spectroscopy was applied here for an in vivo comparative study of the calf muscles of 7 myotonic dystrophy patients at various stages of the disease and 11 healthy volunteers. Both the total sodium content, expressed as the ratio of the ²³Na and ¹H water signals, and the fast transverse relaxation time, T₂₁, determined from the triple quantum-filtered spectra, increased in correlation with the severity of the disease. The results demonstrate that ²³Na NMR enables the quantitation of myotonic dystrophy progression.     

Childhood Malignant Thymoma: Clinical, Therapeutic, and Immunohistochemical Considerations

Malignant thymomas are among the least common mediastinal tumors in the pediatric age group. Thymomas are considered malignant on the basis of macroscopic and microscopic invasiveness. As only 20 well-documented cases involving children have been reported in the literature, the pattern of responsiveness to therapy and the value of prognostic signs is obscure. Two cases of malignant pediatric thymomas are reported with pathognomonic histoimmunological features of aggressive thymoma. One was cured, with a follow-up of 70 months, and one died while on therapy. Analysis of the histological features and the immunoperoxidase staining displays the complexity of pediatric thymomas and the inability to prognosticate the outcome, respectively.     

Acute severe combined demyelination

We present a second case in which Guillain-Barré syndrome (GBS) and acute disseminated encephalomyelitis (ADEM) appeared simultaneously, both in acute and fulminant form. The patient, a 10-year-old girl, presented with acute onset of coma and flaccid, areflexic quadriparesis. The elevated CSF protein levels and delayed F waves fulfilled the criteria of GBS and an MRI study revealed extensive multifocal demyelination compatible with a diagnosis of ADEM. Prompt clinical response followed by complete recovery was achieved by treatment with corticosteroids. It is suggested that acute severe combined demyelination might constitute a separate entity in which the demyelinating process, involving simultaneously the central and the peripheral nervous systems, indicates immune response against a component of the myelin of one system carrying cross-antigenicity with the other.     

In vivo 31P NMR studies of paraplegics' muscles activated by functional electrical stimulation

The bioenergetics of paralyzed muscles of spastic paraplegic patients under functional electrical stimulation (FES) was studied in vivo using ³¹P NMR. The protocol included rest, 3 min of induced tetanic isometric contraction through surface electrodes and 40 min of recovery. The continuous stimulation, the force recording and the ³¹P NMR measurements were sampled simultaneously inside the whole body imager. Normal values were found for the phosphorous metabolite ratios at rest. During contraction, prominent changes were detected including: a) accumulation of inorganic phosphate (P) accompanied by an unusually strong signal in the phosphomonoester (PME) region, b) phosphocreatine (PCr) decline, and c) a decrease in the intracellular pH. In the following recovery period the physiological state of the muscle was monitored and quantitated by ³¹P NMR. No metabolic and mechanical irreversible damage was detected in the paraplegics' muscles activated by FES under our experimental conditions.     

Recurrent retinal artery obstruction as a presenting symptom of ophthalmic artery aneurysm: a case report

Background: Retinal artery obstruction is an ophthalmic emergency requiring immediate treatment. Recurrent episodes are the result of thromboembolic seeding and necessitate diagnostic efforts to find a possible source for this seeding. The most common sources of such seeding are the valves of the heart and the carotid arteries. Case report: We describe a case of a 25-year-old man who had recurrent episodes of retinal artery obstruction due to embolic spread. Discussion: We suggest the origin of the embolic spread to be a post-traumatic ophthalmic artery aneurysm. The immediate and long-term treatment given to the patient are described, the present case is compared to earlier reports, and the unusual clinical picture and suggested treatment are discussed.     

Treatment with lecinoxoids attenuates focal and segmental glomerulosclerosis development in nephrectomized rats

Focal segmental glomerulosclerosis (FSGS) is a scarring process associated with chronic low‐grade inflammation ascribed to toll‐like receptor (TLR) activation and monocyte migration. We developed synthetic, small‐molecule lecinoxoids, VB‐201 and VB‐703, that differentially inhibit TLR‐2‐ and TLR‐4‐mediated activation and monocyte migration. The efficacy of anti‐inflammatory lecinoxoid treatment on FSGS development was explored using a 5/6 nephrectomy rat model. Five‐sixths of nephrectomized rats were treated with lecinoxoids VB‐201, VB‐703 or PBS, for 7 weeks. Upon sacrifice, albumin/creatinine ratio, glomerulosclerosis, fibrosis‐related gene expression and the number of glomerular and interstitial monocyte were evaluated. Treatment of nephrectomized rats with lecinoxoids ameliorated glomerulosclerosis. The percentage of damaged glomeruli, glomerular sclerosis and glomeruli fibrotic score was significantly reduced following VB‐201 and VB‐703 treatment. VB‐703 attenuated the expression of fibrosis hallmark genes collagen, fibronectin (FN) and transforming growth factor β (TGF‐β) in kidneys and improved albumin/creatinine ratio with higher efficacy than did VB‐201, but only VB‐201 significantly reduced the number of glomerular and interstitial monocytes. These results indicate that treatment with TLR‐2, and more prominently, TLR‐4 antagonizing lecinoxioids, is sufficient to significantly inhibit FSGS. Moreover, inhibiting monocyte migration can also contribute to treatment of FSGS. Our data demonstrate that targeting TLR‐2‐TLR‐4 and/or monocyte migration directly affects the priming phase of fibrosis and may consequently perturb disease parthogenesis.     

Cardiovascular impact of testosterone therapy for hypogonadism

Introduction: Since 2010 some evidence supporting the possible increased cardiovascular (CV) risk related to testosterone treatment (TTh) has created much debate in the scientific community. Based on these results, the US Food and Drug Administration agency has questioned TTh for aging men recognizing its value only for classical hypogonadism due to genetic or organic causes. To better clarify this topic, we scrutinized and summarized, also by using meta-analytic methods, the data generated during the last 7 years, as derived from the analysis of randomized controlled trials (RCTs) on TTh and CV risk.

Areas covered: Analysis included 31 RCTs published between 2010 and 2018. Retrieved trials included 2675 and 2308 patients in TTh and placebo groups, respectively. The analysis documented that TTh was not associated with an increased CV mortality or morbidity either when overall or major adverse CV events were considered.

Expert commentary: Despite present evidence it is important to recognize that the duration of the available trials is short (lower that 3 years) limiting final conclusions on this topic. In particular, the available information on possible long-term effects of TTh on CV risk is limited. Long-term safety studies are advisable to better clarify these points.     

Red Blood Cell Distribution Width (RDW) and long-term survival in patients with ST Elevation Myocardial Infarction

Introduction

High RDW values are associated with adverse prognosis in many clinical conditions including short and medium term outcome of patients with ST Elevation Myocardial Infarction (STEMI). The aim of the present study was to evaluate the association between RDW and long term mortality in STEMI patients undergoing primary angioplasty (PPCI).

Material and methods

A cohort of 535 STEMI patients undergoing PPCI were divided into two groups (RDW > 14%, RDW ≤ 14%) using CHAID and CART methods. The association between RDW and 5-year all-cause mortality was assessed using Cox’s proportional hazards analysis.

Results

A total of 37 patients died during follow up of 5 years (mean: 1059, median: 1013, range 2–2130 days). RDW > 14% was associated with increased risk of all-cause mortality (HR = 5, CI 95% 2.7– 9.9, p < 0.001). In multivariate analysis, RDW > 14 remained significantly associated with increased risk for all-cause mortality (HR = 3.8, CI 95% 1.8– 7.99, p < 0.001). Patients with RDW above 14% did not have lower ejection fraction, higher CPK or more conventional risk factors.

Conclusion

RDW value above 14 is independently associated with increased long term all-cause mortality in patients with STEMI undergoing PPCI.