MUSCLE RESEARCH WORK WITH BRITTON CHANCE FROM IN VIVO MAGNETIC RESONANCE SPECTROSCOPY TO NEAR-INFRARED SPECTROSCOPY

Britton Chance has pioneered magnetic resonance spectroscopy(MRS)and near-infrared(NIR)spectroscopy(NIRS)as noninvasive methods for measuring muscle metabolism in vivo from the late 1970s.This review honoring Britton Chance will highlight the progress that has been made in developing and utilizing MRS and NIRS technologies for evaluating skeletal muscle O_(2) dynamics and energetics.Adaptation of MRS and NIRS technology has focused on the validity and reliability of the measurements and extending the methods in physiological and clinical research.Britton Chance has conducted MRS and NIRS research on elite athletes and a number of chronic health conditions,including patients with chronic heart failure,peripheral vascular disease,and neuromuscular myopathies.As MRS and NIRS technologies are practical and useful for measuring human muscle metabolism,we will strive to continue Chance's legacy by advancing muscle MRS and NIRS studies.

Effects of dietary protein restriction on muscle fiber characteristics and m TORC1 pathway in the skeletal muscle of growing-finishing pigs

Background： To investigate the effects of dietary crude protein（CP） restriction on muscle fiber characteristics and key regulators related to protein deposition in skeletal muscle, a total of 18 growing-finishing pigs（62.30 ± 0.88 kg）were allotted to 3 groups and fed with the recommended adequate protein（AP, 16 % CP） diet, moderately restricted protein（MP, 13 % CP） diet and low protein（LP, 10 % CP） diet, respectively. The skeletal muscle of different locations in pigs, including longissimus dorsi muscle（LDM）, psoas major muscle（PMM） and biceps femoris muscle（BFM） were collected and analyzed.Results： Results showed that growing-finishing pigs fed the MP or AP diet improved（P 〈 0.01） the average daily gain and feed： gain ratio compared with those fed the LP diet, and the MP diet tended to increase（P = 0.09） the weight of LDM. Moreover, the ATP content and energy charge value were varied among muscle samples from different locations of pigs fed the reduced protein diets. We also observed that pigs fed the MP diet up-regulated（P 〈 0.05） muscular m RNA expression of all the selected key genes, except that myosin heavy chain（My HC） IIb,My HC IIx, while m RNA expression of ubiquitin ligases genes was not affected by dietary CP level. Additionally, the activation of mammalian target of rapamycin complex 1（m TORC1） pathway was stimulated（P 〈 0.05） in skeletal muscle of the pigs fed the MP or AP diet compared with those fed the LP diet.Conclusion： The results suggest that the pigs fed the MP diet could catch up to the growth performance and the LDM weight of the pigs fed the AP diet, and the underlying mechanism may be partly due to the alteration in energy status, modulation of muscle fiber characteristics and m TORC1 activation as well as its downstream effectors in skeletal muscle of different locations in growing-finishing pigs.

Application of MET Technique after Upper Limb Dysfunction after Breast Cancer Surgery

Object:Explore the application and actual effect of MET(Muscle Energy)technology after breast cancer surgery with upper limb dysfunction.Methods:Taking 40 female breast cancer patients who underwent surgical treatment in our hospital from September 2017 to June 2019 as the research objects,all of them successfully completed modified radical mastectomy for breast cancer.According to different nursing methods,the patients were randomly divided into two groups.The experiment There were 20 cases in each group and the control group.The control group was given routine functional recovery exercise intervention after the operation,and the experimental group added MET technology to the base of the control group.One month after the operation,the functional recovery of the affected limbs of the two groups of patients was effectively assessed.The upper limb dysfunction of the two groups was compared by statistical methods,and the shoulder joint range of motion(ROM)was used for performance.Results:Through early functional recovery training and MET technology,19 cases of ROM in the experimental group showed compliance(95%),compared with only 14 cases(70%)in the control group.The difference in upper limb dysfunction between the two groups is very obvious with statistical significance(P<0.05).Conclusions:Early functional recovery training combined with muscle energy technology can promote the recovery of upper limb dysfunction after breast cancer surgery faster and better,which is conducive to the recovery of patients as soon as possible and improve the quality of life.

Premigratory fat metabolism in hummingbirds： A Rumsfeldian approach

Hummingbird migration is a remarkable feat, given the small body sizes of migratory species, their high metabolic rates during flight and the long distances traveled using fat to fuel the effort. Equally remarkable is the ability of premigratory hummingbirds in the wild to accumulate fat, synthesized from sugar, at rates as high as 10% of body mass per day. This paper summarizes, using Rumsfeldian terminology, ＂known knowns＂ concerning the energetics of hummingbird migration and premi- gratory fattening. Energy metabolism during hover-feeding on floral nectar is fueled directly by dietary sugar through the path- way recently named the ＂sugar oxidation cascade＂. However, flight without feeding for more than a few minutes requires shifting to fat as a fuel. It is proposed that behavior and metabolic fuel choice are coadapted to maximize the rate of fat deposition during premigratory fattening. The hummingbird liver appears to possess extraordinarily high capacities for fatty acid synthesis. The analysis of ＂known knowns＂ leads to identification of ＂known unknowns＂, e.g., the fates of dietary glucose and fructose, the regulation of fat metabolism and metabolic interactions between liver and adipose tissue. The history of science behooves recog- nition of ＂tmknown unknowns＂ that, when discovered serendipitously, might shed new light on fundamental mechanisms as well as human pathological conditions .

A novel function of CREG in metabolic disorders

Metabolic disorders are public health problems that require prevention and new efficient drugs for treatment.Cellular repressor of E1A-stimulated genes(CREG)is ubiquitously expressed in mature tissues and cells in mammals and plays a critical role in keeping cells or tissues in a mature,homeostatic state.Recently,CREG turns to be an important mediator in the development of metabolic disorders.Here in this review,we briefly discuss the structure and molecular regulation of CREG along with the therapeutic strategy to combat the metabolic disorders.