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Short‐chain enoyl‐CoA hydratase (SCEH or ECHS1) deficiency is a rare inborn error of metabolism caused by biallelic mutations in the gene ECHS1 (OMIM 602292). Clinical presentation includes infantile‐onset severe developmental delay, regression, seizures, elevated lactate, and brain MRI abnormalities consistent with Leigh syndrome (LS). Characteristic abnormal biochemical findings are secondary to dysfunction of valine metabolism. We describe four patients from two consanguineous families (one Pakistani and one Irish Traveler), who presented in infancy with LS. Urine organic acid analysis by GC/MS showed increased levels of erythro‐2,3‐dihydroxy‐2‐methylbutyrate and 3‐methylglutaconate (3‐MGC). Increased urine excretion of methacrylyl‐CoA and acryloyl‐CoA related metabolites analyzed by LC‐MS/MS, were suggestive of SCEH deficiency; this was confirmed in patient fibroblasts. Both families were shown to harbor homozygous pathogenic variants in the ECHS1 gene; a c.476A > G (p.Gln159Arg) ECHS1variant in the Pakistani family and a c.538A > G, p.(Thr180Ala) ECHS1 variant in the Irish Traveler family. The c.538A > G, p.(Thr180Ala) ECHS1 variant was postulated to represent a Canadian founder mutation, but we present SNP genotyping data to support Irish ancestry of this variant with a haplotype common to the previously reported Canadian patients and our Irish Traveler family. The presence of detectable erythro‐2,3‐dihydroxy‐2‐methylbutyrate is a nonspecific marker on urine organic acid analysis but this finding, together with increased excretion of 3‐MGC, elevated plasma lactate, and normal acylcarnitine profile in patients with a Leigh‐like presentation should prompt consideration of a diagnosis of SCEH deficiency and genetic analysis of ECHS1. ECHS1 deficiency can be added to the list of conditions with 3‐MGA.

ObjectiveThe amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid receptor (AMPAR) is increasingly recognized as a therapeutic target in drug‐refractory pediatric epilepsy. Perampanel (PER) is a non‐competitive AMPAR antagonist, and pre‐clinical studies have shown the AMPAR‐mediated anticonvulsant effects of decanoic acid (DEC), a major medium‐chain fatty acid provided in the medium‐chain triglyceride ketogenic diet.MethodsUsing brain tissue resected from children with intractable epilepsy, we recorded the effects of PER and DEC in vitro.ResultsWe found resected pediatric epilepsy tissue exhibits spontaneous epileptic activity in vitro, and showed that DEC and PER inhibit this epileptiform activity in local field potential recordings as well as excitatory synaptic transmission.InterpretationThis study confirms AMPAR antagonists inhibit epileptiform discharges in brain tissue resected in a wide range of pediatric epilepsies.

Concern persists about the potential negative inotropic effects of calcium channel blockers in patients with severely depressed myocardial function. Therefore, intravenous diltiazem (100 to 200 micrograms/kg per min infusion) was administered for 40 minutes followed by oral diltiazem (90 to 120 mg/8 hours) for 24 hours to patients with advanced congestive heart failure (New York Heart Association class III to IV, mean ejection fraction 26 +/- 4 [SD]). Intravenous diltiazem (eight patients) increased cardiac index 20% (2.05 +/- 0.8 to 2.47 +/- 0.8 liters/min per m2, p less than 0.01), stroke volume index 50% (22 +/- 9 to 33 +/- 12 ml/m2, p less than 0.001) and stroke work index 27% (19 +/- 10 to 24 +/- 10 g-m/m2, p less than 0.05); while reducing heart rate 23% (97 +/- 18 to 75 +/- 11 beats/min, p less than 0.01), mean arterial pressure 18% (95 +/- 13 to 78 +/- 7 mm Hg) and pulmonary wedge pressure 34% (29 +/- 9 to 19 +/- 7 mm Hg), without altering maximal first derivative of left ventricular pressure (dP/dtmax). Oral diltiazem (seven patients) produced equivalent hemodynamic effects. Transient junctional arrhythmias were observed in three of eight patients with intravenous diltiazem and one of seven patients with oral diltiazem. It is concluded that intravenous and short-term oral diltiazem improve left ventricular performance and reduce myocardial oxygen demand by heart rate and afterload reduction without significantly depressing contractile function in severe congestive heart failure. Caution should be exercised to avoid potential adverse, drug-induced electrophysiologic effects in such patients.

The distribution of mRNA between the detergent-soluble and insoluble (cytoskeleton) fractions in rat L6 myoblast and myotube cells was examined. Approximately 85% of cytoplasmic mRNA in both myoblasts and myotubes was found associated with the cytoskeletal framework. The cytoskeleton-bound mRNA was present as polysomes. In contrast, the mRNA of the detergent-soluble fraction was not associated with ribosomes and was thus considered to be the repressed population. The association of mRN A with the cytoskeletal framework was not affected by treatments leading to dissociation of polysomes. Differential distribution of mRNA between the soluble and cytoskeleton-bound fractions was analyzed by in virro translation. The mRNAs coding for polypeptides of molecular masses 40 kDa and 60 kDa were preferentially enriched in the soluble fraction.The nature of binding between mRNA and the cytoskeletal framework was examined following in vivo crosslinking of RNA and protein by irradiating muscle cells with ultraviolet light. It was observed that this treatment covalently linked RNA and the neighbouring protein moieties without any detectable damage to the cytoskeletal framework, as measured by the distribution of RNAs and proteins between the cytoskeleton and soluble fractions. Analysis of the polypeptide moieties cross-linked to the mRNA have shown that a large number of polypeptides of molecular masses between 15 -220 kDa were associated with both cytoskeleton-bound and soluble mRNAs. The polypeptide moieties of these mRNA-protein complexes were not only similar in the cytoskeleton and soluble mRNA-protein complexes but also were similar between myoblasts and myotubes. However, one polypeptide of 165 kDa was preferentially associated with the cytoskeleton-bound mRNA-protein complexes. Interestingly this 165-kDa polypeptide was also preferentially enriched in the total proteins from the cytoskeleton fraction. This result suggests a possible role of the 165-kDa polypeptide in association between mRNA and the cytoskeletal framework. To examine the mechanism of interaction between mRNA and the cytoskeletal framework we have reported here a ghost monolayer transcription system from myotubes. This transcription system was able to synthesize rRNA and mRNA. The mRNA transcribed in vitro was preferentially associated with the cytoskeleton structure present in the ghost monolayer system. Initiation of translation of mRNA in the cytoplasm is a complex process involving delicately controlled interactions between mRNA and a large number of translational initiation factors [l]. A number of studies have shown that within the cytoplasm of eukaryotic cells there is an elaborate filamentous structure [2]. This internal structure is comprised of specialized proteins and is believed to be involved in a variety of cellular processes like cellular morphology, cell movements, organization of cellular organelles and cytoplasmic streaming. This elaborate filamentous substructure of cell cytoplasm is commonly known as the cytoskeleton [3]. Several lin...