The rate of muscle glycogen synthesis during 2 and 4 h of recovery after depletion by exercise was studied using two energy equivalent carbohydrate drinks, one containing a polyglucoside with a mean molecular mass of 500 000-700 000 (C drink), and one containing monomers and oligomers of glucose with a mean molecular mass of approximately 500 (G drink). The osmolality was 84 and 350 mosmol. l(-1), respectively. A group of 13 healthy well-trained men ingested the drinks after glycogen depleting exercise, one drink at each test occasion. The total amount of carbohydrates consumed was 300 g (4.2 g. kg(-1)) body mass given as 75 g in 500 ml water immediately after exercise and again 30, 60 ad 90-min post exercise. Blood glucose and insulin concentrations were recorded at rest and every 30 min throughout the 4-h recovery period. Muscle biopsies were obtained at the end of exercise and after 2 and 4 h of recovery. Mean muscle glycogen contents after exercise were 52.9 (SD 27.4) mmol glycosyl units. kg(-1) (dry mass) in the C group and 58.3 (SD 35.4) mmol glycosyl units. kg(-1) (dry mass) in the G group. Mean glycogen synthesis rate was significantly higher during the initial 2 h for the C drink compared to the G drink: 50.2 (SD 13.7) mmol. kg(-1) (dry mass). h(-1) in the C group and 29.9 (SD 12.5) mmol. kg(-1) (dry mass). h(-1) in the G group. During the last 2 h the mean synthesis rate was 18.8 (SD 33.3) and 23.3 (SD 22.4) mmol. kg(-1) (dry mass). h(-1) in the C and G group, respectively (n.s.). Mean blood glucose and insulin concentrations did not differ between the two drinks. Our data indicted that the osmolality of the carbohydrate drink may influence the rate of resynthesis of glycogen in muscle after its depletion by exercise.

Background: Despite the fact that patients with obstructive sleep apnoea syndrome (OSAS) often have symptoms at the level of skeletal muscle such as fatigue, the question of whether the structural, cellular and functional properties of limb skeletal muscles are affected has not been fully examined. Objective: The aim was to examine physiological and muscular parameters in patients with OSAS and to assess the relationship between these parameters and the clinical symptoms. Method: Eighteen patients with OSAS and 16 controls participated. Aerobic capacity was assessed using a submaximal test. Fibre type distribution and fibre area were analyzed on muscle biopsies taken from the tibialis anterior. The microvascularization was assessed using the following parameters: (1) the number of capillaries per fibre (CAF), (2) CAF per fibre area (CAFA), (3) capillary to fibre perimeter exchange (CFPE) index, which represents the interface between muscle fibre and capillaries, and (4) length of capillary/perimeter of the fibre (LC/PF) index or capillary tortuosity, which represents the percent of muscle fibre perimeter in contact with the wall of the microvessel. Results: The OSAS group had significantly lower predicted relative maximal oxygen uptake (p = 0.0047) which was inversely correlated to the apnoea/hypopnoea index (AHI; r = –0.6, p = 0.017). There was a significantly higher CFPE index for slow type I fibres (p = 0.007) and fast type II fibres (p = 0.0126) and a significantly higher LC/PF index for type I fibres (p = 0.0003) and type II fibres (p = 0.0285) in OSAS patients compared to controls. Conclusion: OSAS patients have a higher muscle microvascularization and a lower aerobic capacity than controls. Furthermore the aerobic capacity was inversely correlated to AHI.

An increased capillary network has been observed in skeletal muscle of patients with restless legs syndrome (RLS) and obstructive sleep apnea syndrome (OSAS). This finding could be due to upregulation of growth factors responsible for angiogenesis. The aim of the study was to examine the occurrence and localization of VEGF and capillary proliferation in skeletal muscle of RLS (n = 12) and OSAS (n = 12) patients and controls (n = 11). Double-immunofluorescence staining for capillaries (CD31) and VEGF, and proliferating cells (Ki-67), was carried out on biopsies taken from the tibialis anterior. The percentage of capillaries expressing VEGF (CD31,VEGF(+)) was significantly higher in OSAS and RLS patients compared with controls. The percentage of proliferating capillaries (CD31,Ki-67(+)) was significantly higher in OSAS patients compared with controls. Our study shows the occurrence of proliferation of endothelial cells in skeletal muscle in RLS and OSAS, supporting an upregulation of VEGF located in capillaries, probably due to local hypoxia.

The purpose of this pilot study was to investigate intramuscular microcirculation in extensor carpi radialis brevis (ECRB) in patients with lateral epicondylitis. Ten patients with unilateral epicondylitis, mean duration of symptoms of 39 (12-96) months participated. The diagnosis was based on clinical examination and none was under treatment for the last 6 months. Isometric handgrip strength, 2-pinch grip strength and muscle strength during radial deviation and dorsal extension were determined. Functional perceived pain was evaluated by a modified behaviour rating scale and perceived pain during contraction by visual analogue scale. Intramuscular and skin blood flow was recorded by a laser-Doppler flowmetry system technique (LDF) during stable temperature condition. Intramuscular blood flow was significantly lower in the affected side, 22.7+/-9.8 perfusion units (PU), as compared with 35.2+/-11.9 PU in the control side (P=0.01). There was no difference in skin blood flow or temperature between the affected and the control side. A positive correlation was found between the duration of symptoms and the difference in intramuscular blood flow between the affected and the control arm (r=0.65, P=0.06). The present data indicate that decreased microcirculation and anaerobic metabolism in ECRB may contribute to the lateral epicondylitis symptoms.

There was no significant difference in vitamin D levels between the myositis subgroups. When vitamin D levels were subclassified into deficient (<50 nmol/l), insufficient (50-74 nmol/l) and normal (≥75 nmol/l), most of the patients with PM (68%), DM (65%) and IBM (53%) had deficient levels compared with only 60 (21%) healthy individuals. In patients with IIM the OR for deficient versus normal was 17.7 (95% CI 8.1 to 38.6) and the OR for insufficient versus normal was 2.4 (95% CI 1.2 to 4.7). Conclusions Low serum levels of vitamin D were found in most patients with IIM and may confer a risk factor for developing adult myositis, similar to some other autoimmune diseases.