Rotational speed tracking for hydraulic-motor-driven machine-tools

The objective of this work is to design and compare control strategies for tracking certain velocity time functions prescribed for the speed variation of a hydraulic motor axis. Continuous velocity reference trajectories with finitely many acceleration discontinuities are treated. The model for the dynamics of the coupled motor—work-table model is non-linear and linearization has proven to be inadequate for describing the qualitative behaviour of the system. We show that the use of non-linear models increases the stability and accuracy of the control. Exact and approximate techniques are developed, applied and compared whenever possible. The approximate approach leads to a bilinear-quadratic optimal control problem whose solution, obtained through a power series expansion, provides, explicit formulae for general non-linear optimal tracking approximation.     

What do error patterns in processing facial expressions,social interaction scenes and vocal prosody tell us about the way social cognition works in children with 22q11.2DS?

Impairments in social cognition have been frequently described in 22q11.2 deletion syndrome (22q11.2DS) and are thought to be a hallmark of difficulties in social interactions. The present study addresses aspects that are critical for everyday social cognitive functioning but have received little attention so far. Sixteen children with 22q11.2DS and 22 controls completed 1 task of facial expression recognition, 1 task of attribution of facial expressions to faceless characters involved in visually presented social interactions, and 1 task of attribution of facial expressions to characters involved in aurally presented dialogues. All three tasks have in common to involve processing of emotions. All participants also completed two tasks of attention and two tasks of visual spatial perception, and their parents completed some scales regarding behavioural problems of their children. Patients performed worse than controls in all three tasks of emotion processing, and even worse in the second and third tasks. However, they performed above chance level in all three tasks, and the results were independent of IQ, age and gender. The analysis of error patterns suggests that patients tend to coarsely categorize situations as either attractive or repulsive and also that they have difficulties in differentiating emotions that are associated with threats. An isolated association between the tasks of emotion and behaviour was found, showing that the more frequently patients with 22q11.2DS perceive happiness where there is not, the less they exhibit aggressive behaviour.     

Myoclonus in mitochondrial disorders

Myoclonus is a possible manifestation of mitochondrial disorders, and its presence is considered, in association with epilepsy and the ragged red fibers, pivotal for the syndromic diagnosis of MERRF (myoclonic epilepsy with ragged red fibers). However, its prevalence in mitochondrial diseases is not known. The aims of this study are the evaluation of the prevalence of myoclonus in a big cohort of mitochondrial patients and the clinical characterization of these subjects. Based on the database of the “Nation‐wide Italian Collaborative Network of Mitochondrial Diseases,” we reviewed the clinical and molecular data of mitochondrial patients with myoclonus among their clinical features. Myoclonus is a rather uncommon clinical feature of mitochondrial diseases (3.6% of 1,086 patients registered in our database). It is not strictly linked to a specific genotype or phenotype, and only 1 of 3 patients with MERRF harbors the 8344A>G mutation (frequently labeled as “the MERRF mutation”). Finally, myoclonus is not inextricably linked to epilepsy in MERRF patients, but more to cerebellar ataxia. In a myoclonic patient, evidences of mitochondrial dysfunction must be investigated, even though myoclonus is not a common sign of mitochondriopathy. Clinical, histological, and biochemical data may predict the finding of a mitochondrial or nuclear DNA mutation. Finally, this study reinforces the notion that myoclonus is not inextricably linked to epilepsy in MERRF patients, and therefore the term “myoclonic epilepsy” seems inadequate and potentially misleading. © 2014 International Parkinson and Movement Disorder Society     

Muscle glycogenosis and mitochondrial hepatopathy in an infant with mutations in both the myophosphorylase and deoxyguanosine kinase genes

OBJECTIVES: To document 2 apparently incongruous clinical disorders occurring in the same infant: congenital myopathy with myophosphorylase deficiency (McArdle disease) and mitochondrial hepatopathy with liver failure and mitochondrial DNA depletion. METHODS: An infant girl born to consanguineous Moroccan parents had severe congenital hypotonia and hepatomegaly, developed liver failure, and died at 5 months of age. We studied muscle and liver biopsy specimens histochemically and biochemically, and we sequenced the whole coding regions of the deoxyguanosine kinase (dGK) and myophosphorylase (PYGM) genes. RESULTS: Muscle biopsy specimens showed subsarcolemmal glycogen accumulation and negative histochemical reaction for phosphorylase. Liver biopsy specimens showed micronodular cirrhosis and massive mitochondrial proliferation. Biochemical analysis showed phosphorylase deficiency in muscle and cytochrome c oxidase deficiency in liver. We identified a novel homozygous missense G-to-A mutation at codon 456 in exon 11 of PYGM, as well as a homozygous 4-base pair GATT duplication (nucleotides 763-766) in exon 6 of dGK, which produces a frame shift and a premature TGA stop codon at nucleotides 766 to 768, resulting in a truncated 255-amino acid protein. Both mutations were absent in 100 healthy individuals. CONCLUSIONS: Our data further expand the genetic heterogeneity in patients with McArdle disease; confirm the strong relationship between mitochondrial DNA depletion syndrome, liver involvement, and dGK mutations; and suggest that genetic "double trouble" should be considered in patients with unusual severe phenotypes.     

Methylprednisolone Administration in Primary Biliary Cirrhosis Increases Cholic Acid Turnover, Synthesis, and Deoxycholate Concentration in Bile

As immunosuppressive agents, corticosteroids maybe considered an appropriate treatment for primarybiliary cirrhosis, even if bone loss and other sideeffects may occur. We studied biliary lipid metabolism in 10 nonicteric patients, with histologicallyproven primary biliary cirrhosis (stage I-IV). Weadministered methylprednisolone (24 mg daily) for 30days to ascertain its effects on biliary lipidmetabolism, which are largely still unknown. All patientsunderwent a 30-day drug-washout period before enteringthe trial. The following parameters were studied beforeand after methylprednisolone treatment: serum biochemistry; cholic acid pool size, kineticsand synthesis; biliary lipid secretion; biliary bileacid pattern; biliary lipid molar percentage; andcholesterol saturation index. Methylprednisolone induced a statistically significant (Wilcoxon ranktest) increase in cholic acid turnover (from 0.26± 0.04 to 0.50 ± 0.05 K/day, P = 0.005)and synthesis (from 0.42 ± 0.12 to 0.78 ±0.11 mmol/day, P = 0.04), and in bile deoxycholic acid molarpercentage (from 19.4 ± 2.7 to 30.6 ± 4.4%molar, P = 0.01). On the other hand, a significantdecrease in biliary cholesterol molar percentage (from7.9 ± 0.7 to 6.4 ± 0.5 % molar, P =0.005), cholesterol saturation index (from 1.11 ±0.11 to 0.95 ± 0.07, P = 0.05), and biliarycholesterol secretion (from 64.7 ± 5.4 to 53.0± 4.5 mol/hr, P = 0.005) was observed. These findings show thatshort-term administration of methylprednisolone inpatients with primary biliary cirrhosis does not induceexpansion of the cholic acid pool but increases cholicacid synthesis and turnover, as well as intestinalproduction of deoxycholic acid. If long-term treatmentis considered, the beneficial immunosuppressive effectsof corticosteroids have to be weighed against the hepatotoxic properties of deoxycholicacid.     

McArdle disease: the mutation spectrum of PYGM in a large Italian cohort

Deficiency of the muscle isozyme of glycogen phosphorylase is causative of McArdle disease or Glycogen storage disease type V (GSD-V), the most common autosomal recessive disorder of glycogen metabolism. The typical clinical presentation is characterized by exercise intolerance with cramps, and recurrent myoglobinuria. To date, 46 mutations in the PYGM gene have been detected in GSD-V patients. We report the mutational spectrum in 68 Italian patients. We identified 30 different mutations in the PYGM gene, including 19 mutations that have not been reported previously. The novel mutations include: eight missense mutations (c.475G>A, p.G159R; c.689C>G, p.P230R; c.1094C>T, p.A365E; c.1151C>A, p.A384D; c.1182C>T, p.R428C; c.1471C>T, p.R491C; c.2444A>C, p.D815A; c.2477G>C, p.W826S), two nonsense mutations (c.1475G>A, p.W492X; c.1627A>T, p.K543X), five splice site mutations (c.855 +1G>C; c.1092 +1G>A; c. 1093-1G>T; c.1239 +1G>A; c.2380 +1G>A), and four deletions (c.715_717delGTC, p.V239del; c.304delA, p.N102DfsX4; c.1970_2177del, p.V657_G726; c.2113_2114delGG, p.G705RfsX16). Whereas we confirmed lack of direct correlation between the clinical phenotype and the genotype, we also found that the so-called 'common mutation' (p.R50X) accounted for about 43% of alleles in our cohort and that no population-related mutations are clearly identified in Italian patients.