The aim of the study was to investigate the potential of molecular genetic techniques for diagnosing malignant hyperthermia (MH) susceptibility. Six Belgian families were investigated with ...polymorphic genetic markers for linkage with the ryanodine receptor gene (RYR1) on chromosome 19q13. Linkage was excluded in family two. The five other families yielded inconclusive results. Subsequently, family two was further investigated in two consecutive European genome searches. The second genome search generated linkage for this family on chromosome 5. Furthermore, we searched for point mutations in the RYR1 gene. The Gly341Arg mutation was found in 3/11 Belgian families. We reported the apparent relation between the Gly341Arg mutation and increased serum creatine kinase activity at rest. We also reported the diagnostic value of this mutation in a family with motor neuron disease. In another family, a novel RYR1 mutation, G6499A was found. Four RYR1 point mutations have been associated with central core disease (CCD). In five MH families, central cores as well as multi-cores were found on muscle histology. None of these families carried the CCD mutations. In conclusion, molecular genetic techniques will not replace the standard in vitro contracture test, except in selected families with significant linkage results or when a definite mutation is found. The absence of linkage or the absence of known mutations does not exclude MH susceptibility.
General practitioners (GP) can identify potential cardiac arrest victims. They have the opportunity to inform cardiac patients and their families about the risk of sudden cardiac death and can ...motivate family members to attend a CPR-course. To study actual counselling practices concerning basic CPR-training a questionnaire was mailed to a representative sample of Belgian GPs (n = 1119). The level of CPR-training of the GPs was fairly good: 67% had received BLS training on a manikin and 63% had already attended a cardiac arrest event. A discrepancy was observed between the positive attitude towards CPR and the counselling of family members to attend a CPR-course (9%). GPs feared to inflict additional stress to the patient (32%) or the family (43%) or did not know where CPR courses were organised (37%). GPs are a primary target group for CPR-training and should learn how to counsel potential bystanders of a cardiac arrest to attend a CPR-course without inflicting additional anxiety on the patient or his family.
Cyanobacteria have a strong potential for biofuel production due to their ability to accumulate large amounts of carbohydrates. Nitrogen (N) stress can be used to increase the content of ...carbohydrates in the biomass, but it is expected to reduce biomass productivity. To study this trade-off between carbohydrate accumulation and biomass productivity, we characterized the biomass productivity, biomass composition as well as the transcriptome and proteome of the cyanobacterium Arthrospira sp. PCC 8005 cultured under N-limiting and N-replete conditions. N limitation resulted in a large increase in the carbohydrate content of the biomass (from 14 to 74%) and a decrease in the protein content (from 37 to 10%). Analyses of fatty acids indicated that no lipids were accumulated under N-limited conditions. Nevertheless, it did not affect the biomass productivity of the culture up to five days after N was depleted from the culture medium. Transcriptomic and proteomic analysis indicated that de novo protein synthesis was down-regulated in the N-limited culture. Proteins were degraded and partly converted into carbohydrates through gluconeogenesis. Cellular N derived from protein degradation was recycled through the TCA and GS-GOGAT cycles. In addition, photosynthetic energy production and carbon fixation were both down-regulated, while glycogen synthesis was up-regulated. Our results suggested that N limitation resulted in a redirection of photosynthetic energy from protein synthesis to glycogen synthesis. The fact that glycogen synthesis has a lower energy demand than protein synthesis might explain why Arthrospira is able to achieve a similar biomass productivity under N-limited as under N-replete conditions despite the fact that photosynthetic energy production was impaired by N limitation.
Cyanobacteria have a strong potential for biofuel production due to their ability to accumulate large amounts of carbohydrates. Nitrogen (N) stress can be used to increase the content of ...carbohydrates in the biomass, but it is expected to reduce biomass productivity. To study this trade-off between carbohydrate accumulation and biomass productivity, we characterized the biomass productivity, biomass composition as well as the transcriptome and proteome of the cyanobacterium Arthrospira sp. PCC 8005 cultured under N-limiting and N-replete conditions. N limitation resulted in a large increase in the carbohydrate content of the biomass (from 14 to 74%) and a decrease in the protein content (from 37 to 10%). Analyses of fatty acids indicated that no lipids were accumulated under N-limited conditions. Nevertheless, it did not affect the biomass productivity of the culture up to five days after N was depleted from the culture medium. Transcriptomic and proteomic analysis indicated that de novo protein synthesis was down-regulated in the N-limited culture. Proteins were degraded and partly converted into carbohydrates through gluconeogenesis. Cellular N derived from protein degradation was recycled through the TCA and GS-GOGAT cycles. In addition, photosynthetic energy production and carbon fixation were both down-regulated, while glycogen synthesis was up-regulated. Our results suggested that N limitation resulted in a redirection of photosynthetic energy from protein synthesis to glycogen synthesis. The fact that glycogen synthesis has a lower energy demand than protein synthesis might explain why Arthrospira is able to achieve a similar biomass productivity under N-limited as under N-replete conditions despite the fact that photosynthetic energy production was impaired by N limitation.
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