Associations of Low Muscle Mass and the Metabolic Syndrome in Caucasian and Asian Middle-aged and Older Adults

OBJECTIVE

Age-related declines in skeletal muscle mass may confer significant metabolic consequences for older adults. Associations of low muscle mass and metabolic syndrome (MetS) in Caucasians, and comparisons with associations observed in Asian populations, have not been reported. We examined associations of low muscle mass and metabolic syndrome (MetS) in Asian and Caucasian middle-aged and older men and women using criteria for low muscle mass.

DESIGN, SETTING AND PARTICIPANTS

Two population-based studies of Australian (Tasmanian Older Adult Cohort Study; TASOAC; N=1005) and Korean (Korean Sarcopenic Obesity Study; KSOS; N=376) community-dwelling adults, mean age 62 and 58 years, respectively.

MEASUREMENTS

Appendicular lean mass (aLM) determined by dual-energy X-ray absorptiometry and normalised to height squared (aLM/Ht2), weight (aLM/Wt) or body mass index (aLM/BMI). Participants in the lowest sex-specific 20% for aLM measures were defined as having low muscle mass. MetS was defined according to National Cholesterol Education Program Adult Treatment Panel III criteria.

RESULTS

Although Australians demonstrated generally unfavourable anthropometric and metabolic characteristics compared to Koreans, prevalence of MetS was similar (29.5% in Australians and 31.4% in Koreans, respectively). Low aLM/Ht2 was associated with significantly reduced likelihood of MetS in both Australians (OR: 0.30, 95% CI 0.19 - 0.46) and Koreans (OR: 0.31, 95% CI 0.16 - 0.62). Conversely, low aLM/BMI was associated with increased odds for MetS in Australians (OR: 1.78, 95% CI 1.12 - 2.84), but not Koreans (OR: 1.33, 95% CI = 0.67 - 2.64).

CONCLUSION

Low aLM/BMI is associated with significantly increased likelihood of MetS in Australian adults, but not Koreans, suggesting potential differences in effects of low muscle mass relative to body mass on cardiometabolic health in Caucasian and Asian middle-aged and older adults. Low muscle mass relative to height is associated with reduced likelihood of MetS in both populations.

Dietary salt does not influence the disposition of verapamil enantiomers in relation to efflux transporter ABCB1 genetic polymorphism in healthy Korean subjects

To evaluate the effects of dietary salt on the stereoselective disposition of verapamil enantiomers in relation to the transporter ABCB1 2677GG/3435CC and 2677TT/3435TT haplotypes, ten healthy subjects were asked to take diets of three different salt levels for 7 days in a randomized, three-way crossover manner. The plasma concentrations of verapamil and norverapamil enantiomers were determined after a single oral dose of 240 mg verapamil on the last day of each phase. Pharmacokinetic parameters were calculated by non-compartmental analysis techniques and compared among the three different dietary salt phases. Compared with the medium salt diet, the high and low salt diets had no significant effect on the disposition of verapamil enantiomers. Moreover, the ABCB1 haplotypes did not alter the impact of dietary salt, although ABCB1 2677TT/3435TT subjects had slightly, but not significantly, higher C(max) and area under the curve (AUC) and lower T(max) for the verapamil enantiomers than did 2677GG/3435CC subjects in each salt phase.

Development of the “Inje Cocktail” for High-throughput Evaluation of Five Human Cytochrome P450 Isoforms in vivo

To develop and validate an in vivo cocktail method for high-throughput phenotyping of CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A, 12 healthy subjects received five probe drugs alone or simultaneously. The in vivo phenotyping index of CYP2C9, the ratio of 8 h urine concentration of losartan to its metabolite after a single administration of losartan, was not significantly different from that obtained using the five-drug cocktail. Similarly, the ratios of [omeprazole]/[5-hydroxyomeprazole] (CYP2C19) and [paraxanthine]/[caffeine] (CYP1A2) in 4 h plasma samples and the log ratio of [dextromethorphan]/[dextrorphan] (CYP2D6) in 8 h urine samples and the 4 h plasma concentrations of midazolam (CYP3A) after single administration or well-established three-drug cocktail of caffeine, omeprazole, and dextromethorphan were not significantly different from those after the new five-drug cocktail. In conclusion, the new five-drug cocktail regimen, named the "Inje cocktail," can be used as a tool to phenotype in vivo enzyme activities of CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A with only 4 h blood sampling and 8 h urine collection following simultaneous administration of the five probe drugs.

Temperature dependence of DCDD/F isomer distributions from chlorophenol precursors

The temperature dependence of the gas-phase, rate-limited formation of dichlorodibenzo-p-dioxin (DCDD) and dichlorodibenzofuran (DCDF) isomers from 2,6-dichlorophenol and 3-chlorophenol, respectively, has been studied experimentally in an isothermal flow reactor over the range 300-900 degrees C under pyrolytic, oxidative and catalytic conditions and computationally using semi-empirical molecular orbital methods. At high temperatures, distributions of sets of DCDD/F condensation products are consistent with the calculated thermodynamic distributions, indicating that the relative rates of formation are governed by differences in symmetry and steric hindrance present in the isomer product structures. At low temperatures, however, this is not the case. In the case of 1,6- and 1,9-DCDD formed from 2, 6-dichlorophenol via Smiles rearrangement, the 1,6 isomer is favored at low temperatures more than thermodynamically predicted. This result appears to be consistent with kinetic effects of either the expansion of the five-membered ring Smiles intermediate or a lower activation energy six-membered ring intermediate pathway that produces only the 1,6 isomer. For formation of 1,7-, 3,7- and 1,9-DCDF from 3-chlorophenol, the 1,7 isomer fraction increases at low temperatures whereas thermodynamics predicts a decrease. This result can be attributed to steric effects in alternative "sandwich-type" approach geometries of phenoxy radicals to form the o,o'-dihydroxybiphenyl (DOHB) intermediate via its keto-tautomers. Higher level molecular theory (ab initio) is needed to provide a more quantitative description of these kinetics.

Inhibition of lipopolysaccharide-induced I-kappaB degradation and tumor necrosis factor-alpha expression by dimethyl-4,4'-dimethoxy-5,6,5',6'-dimethylene dioxybiphenyl-2,2'-dicarboxylate (DDB): minor role in hepatic detoxifying enzyme expression

AIMS/BACKGROUND

Dimethyl-4,4'-dimethoxy-5,6,5',6'-dimethylene dioxybiphenyl-2,2'-dicarboxylate (DDB) is active against a variety of hepatotoxins and has been used as a curative agent for patients with acute and chronic viral hepatitis. Effects of DDB on the expression of xenobiotic-metabolizing enzymes and on nuclear factor-kappaB (NF-kappaB) activation and tumor necrosis factor-alpha (TNF-alpha) production by lipopolysaccharide (LPS), an endotoxin involved in inflammatory responses, were examined in rats and in RAW264.7 cells to investigate mechanistic aspects.

METHODS

Expression of hepatic cytochrome P450s, microsomal epoxide hydrolase and glutathione S-transferases was determined by immunoblot and Northern blot analyses. Activation of hepatic NF-kappaB and I-kappaBalpha degradation was assessed by gel mobility shift and immunoblot analyses, respectively. LPS-induced TNF-alpha expression was monitored in rats and in RAW264.7 cells by enzyme-linked immunosorbent assay and/or reverse transcription-polymerase chain reaction analysis.

RESULTS

DDB failed to alter the expression of hepatic cytochrome P450 1A and 2C11, microsomal epoxide hydrolase and glutathione S-transferases in rats with slight inhibition of P450 2E1 expression, but induced P450 2B1/2. Pretreatment of rats with DDB prevented LPS-induced hepatic I-kappaBalpha degradation and the resultant NF-kappaB activation, and inhibited the LPS-induced plasma TNF-alpha protein and hepatic TNF-alpha mRNA expression in a dose-dependent manner. LPS-induced I-kappaBalpha degradation and TNF-alpha production were also inhibited by DDB in RAW264.7 cells, which was consistent with the results in rats.

CONCLUSIONS

The present study demonstrated that DDB may inhibit inflammatory responses in association with reduction of NF-kappaB activation through prevention of I-kappaBalpha degradation and subsequent TNF-alpha production, but not with modulation of the detoxifying enzyme expression.

Applicability of ABC-ELISA and protein A-ELISA in serological diagnosis of cysticercosis

Specific antibody test in serum and cerebrospinal fluid (CSF) is still the main mode of serological diagnosis of cysticercosis. Of different techniques of antibody test, enzyme-linked immunosorbent assay (micro-ELISA) has widely been applied. This study was undertaken to observe whether diagnostic capability can be improved by applying more sensitive techniques such as Protein A-ELISA and avidin biotin complex ELISA (ABC-ELISA). When evaluated using 115 sera of human cysticercosis, the antibody positive rates were not significantly improved in Protein A-ELISA (82.6%) and in ABC-ELISA (86.1%) than in micro-ELISA (81.7%). The specificities, evaluated in 165 sera from other diseases and normal controls, were significantly improved (88.5% by micro-ELISA, 93.3% by Protein A-ELISA and 93.8% by ABC-ELISA). Antibody levels (absorbance, abs.) in individual serum were correlated well (r = 0.83-0.86) each other. An actual benefit of Protein A-ELISA and ABC-ELISA was that they needed smaller amount of test sample.

Functional ranges of motion of the wrist joint

We have examined 40 normal subjects (20 men and 20 women) to determine the ideal range of motion required to perform activities of daily living. The amount of wrist flexion and extension, as well as radial and ulnar deviation, was measured simultaneously by means of a biaxial wrist electrogoniometer. The entire battery of evaluated tasks could be achieved with 60 degrees of extension, 54 degrees of flexion, 40 degrees of ulnar deviation, and 17 degrees of radial deviation, which reflects the maximum wrist motion required for daily activities. The majority of the hand placement and range of motion tasks that were studied in this project could be accomplished with 70 percent of the maximal range of wrist motion. This converts to 40 degrees each of wrist flexion and extension, and 40 degrees of combined radial-ulnar deviation. This study provides normal standards for the functional range of motion of the wrist.

SSMB syndrome. Symptomatic supernumerary muscle belly syndrome

Supernumerary muscle bellies (SMBs) of the forearm, common anatomic variant, are usually asymptomatic but can produce a debilitating pain syndrome that is secondary to a tendon-muscle shear phenomenon. This shear phenomenon seems to occur when a SMB is attached to another muscle and the excursion of the two units are different, thus parts of a muscle unit are prevented from migrating proximally on contraction of the entire muscle. The anomalous muscle may have either greater excursion, as in an anomalous palmaris longus attached to the flexor digitorum superficialis, or less excursion, as in an anomalous superficialis muscle attached to the carpus. The shear at the interface between different muscle-tendon units produces a burning pain that usually is localized to the distal one-third of the forearm. Surgical excision of the abnormal restricting muscle or tendon component relieves the symptom complex and restores the ability to apply full power. Observation on typical cases, diagnostic methods, operative technique, and results of the syndrome suggest that SSMB may be responsible for undiagnosed and untreated instances of distal forearm complaints.

Matched distal ulnar resection

Painful disorders of the distal radioulnar joint severely limit the work capability of the hand. Until recently, the standard treatment for this problem has been transverse resection of the distal ulna, as originally proposed by Darrach. A technique for a "matched" resection arthroplasty of the distal ulna, leaving the ulnar shaft--styloid axis along with the triangular fibrocartilage complex and the distal ulnar ligamentous attachments intact, has been used since 1967. This procedure resects the distal ulna in a long, smooth, convex curve, matching the opposing surface of the concave radial metaphysis in three dimensions. Forty-four wrists were followed for an average of 6.5 years and showed that the procedure is reliable and relieves pain while retaining a more normal ulnocarpal, radioulnar, and radiocarpal alignment, with painless pronation averaging 80.5 degrees and supination of 88.5 degrees.