Effect of L-carnitine supplementation on the body carnitine pool, skeletal muscle energy metabolism and physical performance in male vegetarians.

PURPOSE: More than 95% of the body carnitine is located in skeletal muscle, where it is essential for energy metabolism. Vegetarians ingest less carnitine and carnitine precursors and have lower plasma carnitine concentrations than omnivores. Principle aims of the current study were to assess the plasma and skeletal muscle carnitine content and physical performance of male vegetarians and matched omnivores under basal conditions and after L-carnitine supplementation. RESULTS: Sixteen vegetarians and eight omnivores participated in this interventional study with oral supplementation of 2 g L-carnitine for 12 weeks. Before carnitine supplementation, vegetarians had a 10% lower plasma carnitine concentration, but maintained skeletal muscle carnitine stores compared to omnivores. Skeletal muscle phosphocreatine, ATP, glycogen and lactate contents were also not different from omnivores. Maximal oxygen uptake (VO2max) and workload (P max) per bodyweight (bicycle spiroergometry) were not significantly different between vegetarians and omnivores. Sub-maximal exercise (75% VO2max for 1 h) revealed no significant differences between vegetarians and omnivores (respiratory exchange ratio, blood lactate and muscle metabolites). Supplementation with L-carnitine significantly increased the total plasma carnitine concentration (24% in omnivores, 31% in vegetarians) and the muscle carnitine content in vegetarians (13%). Despite this increase, P max and VO2max as well as muscle phosphocreatine, lactate and glycogen were not significantly affected by carnitine administration. CONCLUSIONS: Vegetarians have lower plasma carnitine concentrations, but maintained muscle carnitine stores compared to omnivores. Oral L-carnitine supplementation normalizes the plasma carnitine stores and slightly increases the skeletal muscle carnitine content in vegetarians, but without affecting muscle function and energy metabolism.

Small reciprocal insertion detected by spectral karyotyping (SKY) and delimited by array-CGH analysis.

A 5.4-year-old male propositus is reported with mild dysmorphic features including hypoplasia of the radial part of both hands affecting thenar, thumb and fingers 2-3, incomplete syndactyly of fingers 3-4, single palmar creases, brachymesophalangia of toes 3-5, dissociated retardation of bone age, telecanthus, spina bifida occulta, cryptorchidism, muscular hypotonia, and borderline mental retardation. His karyotype was unbalanced, 46,XY,der(16)ins(4;16)(q26q28.1; q12.1q12.2)pat. In the propositus' father who had brachydactyly of fingers 2-5 and brachymesophalangia of toes 3-5 the insertion was reciprocal, 46,XY,rep ins(4;16)(q26q28.1;q12.1q12.2). Insertions are rare, reciprocal insertions most unusual. The characterization of the insertion in the propositus and the detection of its reciprocity in the father were achieved by the application of spectral karyotyping (SKY). Further examination of the propositus' unbalanced genome by array-CGH analysis delimited the chromosomal locations of the deletion/insertion rearrangement on a 0.5-2 Mb resolution level and allowed to design specific BAC FISH analyses that pinpointed the borders of the affected segments. The rearrangement involved a segment of 7.7 Mb between RP11-1030 g22 and RP11-52k8 at the chromosomal regions 4q26 and 4q28.1, respectively, and a segment of 2.8 Mb between RP11-242n20 at 16q12.1 and RP11-324d17 at 16q12.2. A simple molecular genetic explanation of the phenotype cannot be given. A relation to the Townes Brocks gene (SALL1) located 340 kb proximal of the 16q12 deletion/insertion is unlikely. Possibly more relevant is an overlap of the 16q12 deletion/insertion with a small deletion of the syntenic chromosomal region in the mouse that causes a developmental disorder of digits ("Fused toes").

Centromeric chromosomal translocations show tissue-specific differences between squamous cell carcinomas and adenocarcinomas.

Structural chromosomal aberrations are common in epithelial tumors. Here, we compared the location of centromeric breaks associated with whole arm translocations in seven adenocarcinoma cell lines and nine squamous cell carcinoma cell lines using SKY, microarray-based comparative genomic hybridization (array CGH) and fluorescence in situ hybridization (FISH). Whole arm translocations were more frequent in squamous cell carcinomas (112 in nine cell lines and nine in one short-term culture) than in adenocarcinomas (13 in seven cases) and most often resulted in copy number alterations. Array CGH analysis demonstrated that in all squamous cell carcinomas and in most adenocarcinomas, the breakpoints of unbalanced whole arm translocations occurred between the two clones on the array flanking the centromeres. However, FISH with centromeric probes revealed that in squamous cell carcinomas, the marker chromosomes with whole arm translocations contained centromeres comprised of material from both participating chromosomes, while in adenocarcinomas centromeric material from only one of the chromosomes was present. These observations suggest that different mechanisms of centromeric instability underlie the formation of chromosomal aberrations in adenocarcinomas and squamous cell carcinomas.