DARS2 mutations in mitochondrial leucoencephalopathy and multiple sclerosis.

BACKGROUND: Leucoencephalopathy with brain stem and spinal cord involvement and high brain lactate (LBSL) was first defined by characteristic magnetic resonance imaging and spectroscopic findings. The clinical features include childhood or juvenile onset slowly progressive ataxia, spasticity, and dorsal column dysfunction, occasionally accompanied by learning difficulties. Mutations in DARS2, encoding mitochondrial aspartyl-tRNA synthetase, were recently shown to cause LBSL. The signs and symptoms show some overlap with the most common leucoencephalopathy of young adults, multiple sclerosis (MS). OBJECTIVE: To clarify the molecular background of LBSL patients in Finland, and to look for DARS2 mutations in a group of MS patients. METHODS: Clinical evaluation of LBSL patients, DARS2 sequencing and haplotype analysis, and carrier frequency determination in Finland. RESULTS: All eight LBSL patients were compound heterozygotes for DARS2 mutations: all carried R76SfsX5 change, seven had M134_K165del, and one had C152F change. Axonal neuropathy was found in five of the eight patients. The carrier frequencies of the R76SfsX5 and M134_K165del mutations were 1:95 and 1:380, respectively. All patients shared common European haplotypes, suggestive of common European LBSL ancestors. No enrichment of the two common DARS2 mutations was found in 321 MS patients. CONCLUSION: All LBSL patients were compound heterozygotes, which suggests that DARS2 mutation homozygosity may be lethal or manifest as a different phenotype. The authors show here that despite identical mutations the clinical picture was quite variable in the patients. Axonal neuropathy was an important feature of LBSL. DARS2 mutations cause childhood-to-adolescence onset leucoencephalopathy, but they do not seem to be associated with MS.

Wines as possible meat marinade ingredients possess antimicrobial potential against Campylobacter.

This research studied the survival of high (7 log cfu/mL) and low (3 log cfu/mL) inoculum levels of Campylobacter in white and red wines and in grape and tomato juices, which could function as potential antimicrobial marinade ingredients. For comparison, survival was also studied in a commercial poultry meat marinade. White and red wines were shown to have very high bactericidal effects against Campylobacter. High counts were rapidly inactivated to undetectable numbers within 15 min in white wine and within 1 h in red wine, and low counts within 15 min in white wine and within 30 min in red wine. By contrast, grape and tomato juices did not possess high bactericidal effects against Campylobacter because even low counts were occasionally detected after 48 h. The commercial marinade had rather high bactericidal effects against Campylobacter; the high counts were inactivated in most cases within 48 h, and all the low counts were inactivated within 3 h. When testing chicken meat inoculated with Campylobacter and subsequently submerged in white or red wine, the antibacterial activity of the wine was largely reduced. Wines lowered the Campylobacter load inoculated on chicken meat by approximately 1 log cfu/mL over 48 h. The results suggest that wines could be used as antimicrobial ingredients together with the addition of further antimicrobial agents in meat marinades to reduce the numbers of Campylobacter in naturally contaminated poultry products, thus lowering the risk of Campylobacter cross-contamination and transmission through food.

Use of ultraviolet irradiation to reduce Campylobacter jejuni on broiler meat.

The effects of UV irradiation at a wavelength of 254 nm on the survival of Campylobacter jejuni on the surfaces of broiler meat, skin, and carcasses were studied. On broiler carcasses, the effects of UV were also studied in combination with activated oxygen. The surfaces were inoculated with varying counts of C. jejuni and treated with UV irradiation using doses ranging between 9.4 and 32.9 mW/s per square centimeter. The log reductions in C. jejuni counts were determined by dilution plating. The effects of both treatments on the sensory quality of broiler meat, including visual appearance, odor, and fatty acid composition, were also evaluated. On broiler meat, the maximum reduction achieved was 0.7 log and on broiler skin 0.8 log. On broiler carcasses, the maximum reduction using UV irradiation was 0.4 log, and using UV in combination with activated oxygen 0.4 log. No significant differences were found in the sensory quality between the samples and the controls. The use of UV irradiation alone or in combination with activated oxygen cannot be recommended as a primary decontamination method for C. jejuni on broiler carcasses. The use of these methods in combination with other decontamination techniques, and processing with proper processing plant sanitation and hygiene, might be more effective in reducing the C. jejuni counts on broiler carcass surfaces than the use of these methods only.

Distribution of Campylobacter jejuni isolates from turkey farms and different stages at slaughter using pulsed-field gel electrophoresis and flaA-short variable region sequencing.

The aim of this study was to assess the diversity of thermotolerant Campylobacter spp. isolated from turkey flocks at six rearing farms 1-2 weeks prior to slaughter (360 faecal swab samples) and from 11 different stages at the slaughterhouse (636 caecal, environmental, neck skin and meat samples). A total of 121 Campylobacter isolates were identified to species level using a multiplex PCR assay and were typed by pulsed-field gel electrophoresis (PFGE) and flaA-short variable region (SVR) sequencing. All Campylobacter isolates were identified as Campylobacter jejuni. PFGE analysis with KpnI restriction enzyme resulted in 11 PFGE types (I-XI) and flaA SVR typing yielded in nine flaA-SVR alleles. The Campylobacter-positive turkey flocks A, C and E were colonized by a limited number of Campylobacter clones at the farm and slaughter. The present study confirms the traceability of flock-specific strains (PFGE types I, V and IX; flaA types 21, 36 and 161) from the farm along the entire processing line to meat cuts. It seems that stress factors such as high temperature of the defeathering water (54-56 °C), drying of the carcass skin during air chilling (24 h at 2 °C), and oxygen in the air could not eliminate Campylobacter completely. Campylobacter-negative flocks became contaminated during processing by the same subtypes of Campylobacter introduced into the slaughter house by preceeding positive flocks even if they were slaughtered on subsequent days. Proper and efficient cleaning and disinfection of slaughter and processing premises are needed to avoid cross-contamination, especially in countries with a low prevalence of Campylobacter spp. The majority of flaA SVR alleles displayed a distinct association with a specific PFGE type. However, a linear relationship for all strains among both typing methods could not be established. To specify genetic relatedness of strains, a combination of different genotyping methods, is needed.

POLG1 manifestations in childhood.

OBJECTIVE: Mitochondrial DNA polymerase γ (POLG1) mutations in children often manifest as Alpers syndrome, whereas in adults, a common manifestation is mitochondrial recessive ataxia syndrome (MIRAS) with severe epilepsy. Because some patients with MIRAS have presented with ataxia or epilepsy already in childhood, we searched for POLG1 mutations in neurologic manifestations in childhood. METHODS: We investigated POLG1 in 136 children, all clinically suspected to have mitochondrial disease, with one or more of the following: ataxia, axonal neuropathy, severe epilepsy without known epilepsy syndrome, epileptic encephalopathy, encephalohepatopathy, or neuropathologically verified Alpers syndrome. RESULTS: Seven patients had POLG1 mutations, and all of them had severe encephalopathy with intractable epilepsy. Four patients had died after exposure to sodium valproate. Brain MRI showed parieto-occipital or thalamic hyperintense lesions, white matter abnormality, and atrophy. Muscle histology and mitochondrial biochemistry results were normal in all. CONCLUSIONS: POLG1 analysis should belong to the first-line DNA diagnostic tests for children with an encephalitis-like presentation evolving into epileptic encephalopathy with liver involvement (Alpers syndrome), even if brain MRI and morphology, respiratory chain activities, and the amount of mitochondrial DNA in the skeletal muscle are normal. POLG1 analysis should precede valproate therapy in pediatric patients with a typical phenotype. However, POLG1 is not a common cause of isolated epilepsy or ataxia in childhood.

The expression of SOCS is altered in rheumatoid arthritis.

OBJECTIVES: Cytokines play a key pathogenic role in rheumatoid arthritis (RA). Several cytokines signal through the JAK-STAT pathway, which is negatively regulated by the suppressors of cytokine signalling (SOCS) proteins. Since SOCS protein levels can profoundly modulate cellular responses to cytokines, we have investigated their expression in chronic RA. METHODS: The levels of SOCS1-3 and CIS1 mRNA in peripheral blood (PB) and synovial fluid (SF) mononuclear cells (MCs), purified T cells and monocytes from RA patients and healthy volunteers were studied using quantitative reverse transcriptase polymerase chain reaction (RT-PCR). SOCS mRNA and protein expression in synovial tissues were examined by RT-PCR and immunohistochemistry. RESULTS: The levels of SOCS1 and SOCS3 were significantly increased in PBMCs from RA patients when compared with healthy volunteers. These differences were mainly due to up-regulation of SOCS1 in PB T cells and of SOCS3 in PB monocytes. In addition, SOCS2 was up-regulated in PB T cells. Interestingly, SF T cells expressed lower and SF macrophages higher levels of SOCS molecules than their PB counterparts. Similarly, while a significant portion of macrophages in synovial tissues expressed SOCS1 and SOCS3 proteins, the majority of T cells remained SOCS negative. Finally, SOCS1 was up-regulated in the synovial membranes from patients with RA when compared with osteoarthritis. CONCLUSIONS: SOCS expression levels are profoundly altered in RA, and the profile of SOCS expression is dependent on both the cell type as well as the cellular compartment.

Unconsciousness associated with midazolam and erythromycin.

An 8-yr-old boy suffering from an asymptomatic ventricular septal defect was given erythromycin for antibiotic prophylaxis before adenoidectomy. Sixty minutes after premedication with oral midazolam 0.5 mg kg-1 and oral atropine 0.03 mg kg-1, an infusion of erythromycin 400 mg was started. When 200 mg of erythromycin had been infused, the patient lost consciousness, but other vital functions remained normal. After 45 min, he awakened spontaneously. At the time the plasma concentration of midazolam was 134 ng ml-1. In order to investigate possible interactions between midazolam and erythromycin, we studied the pharmacokinetics of midazolam in six children of the same age undergoing minor otolaryngological surgery. The plasma concentration of midazolam in the patient who lost consciousness was significantly greater than in six other children without concomitant administration of erythromycin. The altered pharmacokinetics of midazolam may result from reduced hepatic clearance of midazolam caused by an enzyme inhibiting drug, erythromycin.