The ß(2) -adrenergic receptor (ADRB2) is located on smooth muscle cells and is an important regulator of smooth muscle tone. The Thr164Ile polymorphism (rs1800888) in the ADRB2 gene is rare but has profound functional consequences on receptor function and could cause lifelong elevated smooth muscle tone. We tested the hypothesis that Thr164Ile is associated with increased blood pressure, increased frequency of hypertension and increased risk of cardiovascular disease (CVD).
A total of 66 750 individuals from two large Danish general population studies were genotyped, and 1943 Thr164Ile heterozygotes and 16 homozygotes were identified.
Thr164Ile genotype was associated with increased systolic and diastolic blood pressure in women (trend: P = 0.04 and 0.02): systolic and diastolic blood pressure increased by 5% and 2%, respectively, in female homozygotes compared with female noncarriers. All female Thr164Ile homozygotes had hypertension compared with 58% of female heterozygotes and 54% of female noncarriers (chi-square: P = 0.001). Female Thr164Ile homozygotes and heterozygotes had odds ratios for ischaemic heart disease (IHD) of 2.93 (0.56-15.5) and 1.28 (1.03-1.61), respectively, compared with female noncarriers (trend: P = 0.007). These differences were not observed in men. Furthermore, Gly16Arg (rs1042713) and Gln27Glu (rs1042714) in the ADRB2 gene were not associated with blood pressure, hypertension or CVD either in the population overall or in women and men separately.
ADRB2 Thr164Ile is associated with increased blood pressure, increased frequency of hypertension and increased risk of IHD amongst women in the general population. These findings, particularly for homozygotes, are novel.
We assessed changes in skeletal muscle energy metabolism by 31P-magnetic resonance spectroscopy (31P-MRS) and oxygen supply by near-infrared spectroscopy (NIR), after exercise and after administration of glucose and a branched-chain amino acids (BCAA), in healthy volunteers and patients with liver cirrhosis. As for the patients with liver cirrhosis, 4 were classified in Child-Pugh Grade A and the other 4 in Grade B. In patients with liver cirrhosis, the intramuscular pH and PCr index (PCr/PCr + Pi) were lower than in healthy subjects after exercise in the fasting state; the deltapH and deltaPCr index were statistically siginificant (p
Soft shell crab is a seafood delicacy in many parts of the world. In Denmark, it has been investigated whether a commercial production of soft shell European green crabs (Carcinus maenas) would be feasible. In relation to this, a feeding study was performed to examine if occurrence of DSP toxins in the product could be a food safety problem. The crabs were fed with mussels containing DSP toxins (2500 microg total okadaic acid equivalents/kg) for 17 days and then fasted for 19 days. The content of total okadaic acid equivalents in the digestive organs was on average 27 times higher than the corresponding content in the body meat. The highest level of total okadaic acid equivalents measured was 12 microg/kg in body meat and 503 microg/kg in digestive organs. The results show that the content of DSP toxins in a commercial product of soft shell European green crab (without digestive organs) could be regarded as negligible.
The biological fate of the fish feed additive, ethoxyquin (EQ) was examined in the muscle of Atlantic salmon during 12 weeks of feeding followed by a 2 weeks depuration period. Parent EQ (1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline), quinone imine (2,6-dihydro-2,2,4-trimethyl-6-quinolone), de-ethylated EQ (6-hydroxy-2,2,4-trimethyl-1,2-dihydroquinoline) and EQDM (EQ dimer or 1,8'-di(1,2-dihydro-6-ethoxy-2,2,4-trimethyl-quinoline) were found to be the ubiquitous metabolites of dietary EQ, with EQDM as a main metabolite. A rapid decrease in the level of EQ (2.4 days of half-life) was balanced by an increase in EQDM, giving an unchanged net sum following 2 weeks of depuration. The mandatory 14 days depuration period prior to slaughtering of farmed salmon in Norway was not sufficient for complete elimination of EQ-derived residuals. Post depuration, EQDM accounted for 99% of sum of the two compounds in all treatment groups; possible toxicological effects of EQDM are not known. The individual concentrations of EQ and EQDM and their sum are dependent on EQ level in the feed, consequently, their residual concentrations may be controlled. The theoretical amount of EQ and EQDM consumed in one meal of farmed salmon would be under the recommended ADI, provided that the fish were raised on feed with no more than 150 mg EQ/kg feed, which is the EU maximum limit for EQ in fish feed.
Accumulation of artificial and natural radionuclides in the chains of food webs leading to non-predatory and piscivorous fish of the Yenisei River was investigated during one year before and three years after the shutdown of a nuclear power plant at the Mining-and-Chemical Combine (2009-2012). The activity of artificial radionuclides in the samples of biota ofthe Yenisei River (aquatic moss, gammarids, dace, grayling, pike) was estimated. The concentration of radionuclides with induced activity (51Cr, 54Mn, 58Co, 60Co, 65Zn, 141, 144Ce, 152, 154Eu, 239Np) decreased in the biomass of biota after the shutdown of the nuclear power plant; the concentration of 137Cs did not. Analysis of the accumulation factors (C(F)) allows us to expect the effective accumulation of 137Cs in the terminal level of the food web of the Yenisei River--pike (C(F) = 2.0-9.4), i.e. biomagnifications of radiocesium. Accumulation of artificial, radionuclides in non-predatory fish from gammarids was not effective (C(F)
BACKGROUND: Aging-related hyperglycemia is associated with increased oxidative stress and diminished muscle glucose transporter-4 (Glut4) that may be regulated, at least in part, by the mitogen-activated protein kinases (MAPK). METHODS: To test the possibility that aging-related hyperglycemia can be prevented by pharmacological manipulation of MAPK hyperactivation, aged (27-month old) Fischer 344/NNiaHSD x Brown Norway/BiNia F1 (F344BN) rats were administered acetaminophen (30 mg/kg body weight/day) for 6 months in drinking water. RESULTS: Hepatic histopathology, serum aspartate aminotransferase and alanine aminotransferase analyses suggested that chronic acetaminophen did not cause hepatotoxicity. Compared with adult (6-month) and aged (27-month) rats, very aged rats (33-month) had higher levels of blood glucose, phosphorylation of soleus p38-MAPK and extracellular-regulated kinase 1/2 (ERK1/2), superoxide and oxidatively modified proteins (p
Age-related increases in oxidative stress contribute to impaired skeletal muscle vascular control. However, recent evidence indicates that antioxidant treatment with tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl) attenuates flow-mediated vasodilation in isolated arterioles from the highly oxidative soleus muscle of aged rats. Whether antioxidant treatment with tempol evokes similar responses in vivo at rest and during exercise in senescent individuals and whether this effect varies based on muscle fiber type composition are unknown. We tested the hypothesis that redox modulation via acute systemic tempol administration decreases vascular conductance (VC) primarily in oxidative hindlimb locomotor muscles at rest and during submaximal whole body exercise (treadmill running at 20 m/min, 5% grade) in aged rats. Eighteen old (25-26 mo) male Fischer 344 x Brown Norway rats were assigned to either rest (n = 8) or exercise (n = 10) groups. Regional VC was determined via radiolabeled microspheres before and after intra-arterial administration of tempol (302 µmol/kg). Tempol decreased mean arterial pressure significantly by 9% at rest and 16% during exercise. At rest, similar VC in 26 out of 28 individual hindlimb muscles or muscle parts following tempol administration compared with control resulted in unchanged total hindlimb muscle VC (control: 0.18 ± 0.02; tempol: 0.17 ± 0.05 ml·min(-1)·100 g(-1)·mmHg(-1); P > 0.05). During exercise, all individual hindlimb muscles or muscle parts irrespective of fiber type composition exhibited either an increase or no change in VC with tempol (i.e., ?11 and ?17 muscles or muscle parts), such that total hindlimb VC increased by 25% (control: 0.93 ± 0.04; tempol: 1.15 ± 0.09 ml·min(-1)·100 g(-1)·mmHg(-1); P = 0.05). These results demonstrate that acute systemic administration of the antioxidant tempol significantly impacts the control of regional vascular tone in vivo presumably via redox modulation and improves skeletal muscle vasodilation independently of fiber type composition during submaximal whole body exercise in aged rats.
We present a case report of acute bilateral excercise-induced compartment syndrome in the adductor longus muscles, which was treated with bilateral medial fasciotomies. Postoperatively, the healing process of the adductor muscles was followed up by repeated MR imagings over six months. Myonecrosis was found in peroperative muscle biopsies. Pain and muscle swelling subsided soon after the fasciotomy, correlating with the early postoperative MR findings. Four months postoperatively, the signal intensity of the adductor muscles was normal in T1- and T2-weighted images, but the normal fibre structure of the adductor muscles could only be seen 6 months postoperatively. At six month's control checkup there was no subjective weakness of the adductors, and hyperesthesia had disappeared and the patient was capable of normal activities.
The purpose of the present study was to examine the incidence rates of acute hamstring injuries in Danish elite football sustained during training or match play. Furthermore, it was our intention to document details about the recurrence, severity and the injury seasonal distribution. Hamstring injuries among 374 elite football players were registered prospectively during a 12-month period. A total of 46 first-time and eight recurrent hamstring injuries were registered. The incidence rates for incurring a first-time hamstring injury showed a significantly (P28 days from injury to injury free). Each team sustained a mean of 3.4 hamstring injuries per season, with a mean of 21.5 days missed per injury (range 3-136; median 16 days per injury). The seasonal distribution showed an accumulation of injuries in the first 2 months after a 3.5-month mid-season winter break.
Hamstring strain is a common injury in sprinters and jumpers, and therefore time to return to sport and secondary prevention become of particular concern.
To compare the effectiveness of two rehabilitation protocols after acute hamstring injury in Swedish elite sprinters and jumpers by evaluating time needed to return to full participation in the training process.
Prospective randomised comparison of two rehabilitation protocols.
Fifty-six Swedish elite sprinters and jumpers with acute hamstring injury, verified by MRI, were randomly assigned to one of two rehabilitation protocols. Twenty-eight athletes were assigned to a protocol emphasising lengthening exercises, L-protocol, and 28 athletes to a protocol consisting of conventional exercises, C-protocol. The outcome measure was the number of days to return to full training. Re-injuries were registered during a period of 12 months after return.
Time to return was significantly shorter for the athletes in the L-protocol, mean 49 days (1SD±26, range 18-107 days), compared with the C-protocol, mean 86 days (1SD±34, range 26-140 days). Irrespective of protocol, hamstring injuries where the proximal free tendon was involved took a significantly longer time to return than injuries that did not involve the free tendon, L-protocol: mean 73 vs 31 days and C-protocol: mean 116 vs 63 days, respectively. Two reinjuries were registered, both in the C-protocol.
A rehabilitation protocol emphasising lengthening type of exercises is more effective than a protocol containing conventional exercises in promoting time to return in Swedish elite sprinters and jumpers.