Immediate effects of transcutaneous electrical nerve stimulation on gait patterns in chronic stroke survivors: A single group, pretest-posttest clinical trial.

BACKGROUND: Transcutaneous electrical nerve stimulation (TENS) has been used to reduce muscle spasticity and improve locomotion in stroke survivors. We speculate that acute changes in gait performance after TENS mediate functional improvement in the long-term. However, no previous study has investigated the effect of TENS on ankle kinetics and kinematics during walking in stroke survivors. PURPOSE: We aimed to investigate whether TENS applied over the paretic leg could rapidly improve the plantar flexion moment and ankle kinematics in chronic stroke survivors with lower limb paresis. METHODS: Twenty chronic stroke survivors were recruited. They underwent 30 min of TENS over the area innervated by the common peroneal nerve on the paretic leg. Three-dimensional (3D) motion capture was performed and ankle plantar flexor spasticity was assessed before and immediately after stimulation. Ankle kinematics and kinetic and spatiotemporal data were collected using 3D motion capture. Ankle plantar flexor spasticity was assessed using the Modified Tardieu Scale. PRINCIPAL RESULTS: A significant increase in the ankle plantar flexion moment of the paretic side during the pre-swing phase was observed immediately after stimulation (p = 0.009, maximal mean difference = 0.035, 95%CI = 0.0125 to 0.0575). The step length of the paretic limb also increased significantly after stimulation (p = 0.023, mean difference = -0.02, 95%CI = -0.04 to -0.004). TENS had no immediate effect on paretic ankle spasticity, as measured by the Modified Tardieu Scale, or on other temporo-spatial parameters. CONCLUSION: The findings support the use of TENS to improve the motor function and gait pattern in chronic stroke survivors. The study indicated that the application of TENS to the paretic leg before gait training might improve rehabilitation outcomes. Future studies investigating the effects of TENS on functional outcomes, the optimal stimulation duration, and assessing spasticity using more sensitive measures are warranted.

Effects of Mo contents on the microstructure, properties and cytocompatibility of the microwave sintered porous Ti-Mo alloys.

The porous Ti-Mo alloys were prepared by microwave sintering, and the effects of Mo contents on the pore structure, phase composition, compressive strength, elastic modulus, bending strength, corrosion resistance and cytocompatibility of porous Ti-Mo alloys were investigated. The results show that the porous Ti-Mo alloys are composed of α phase and ß phase, and the volume fraction of ß phase increases with increasing the Mo contents. The amount of Kirkendall pores distributed over the porous Ti-Mo alloys skeleton increases with increasing the Mo contents, which greatly increases the porosities and pore sizes of the porous Ti-Mo alloys. Correspondingly, all of the compressive strength, elastic modulus and bending strength of the porous Ti-Mo alloys decrease with increasing the Mo contents. The porous Ti-Mo alloys present excellent corrosion resistance in the Hank's solution due to the oxidation film of TiO2, MoO2 and MoO3 naturally formed on the surface, and the Mo contents have no obvious effect on the corrosion resistance. The cell viabilities of the porous Ti-Mo alloys are higher than 94%, indicating the porous Ti-Mo alloys possess favorable cytocompatibility. Moreover, the porous Ti-Mo alloys are beneficial to the spread, proliferation and differentiation of osteoblast-like cells, and the Mo contents have no significant effect on the cytocompatibility of the porous Ti-Mo alloys.

Sex difference in high density lipoprotein cholesterol in six countries.

It is known that women have higher levels of high density lipoprotein (HDL) cholesterol than men. The authors examined the association between HDL cholesterol and biologic sex in 8,631 women and 10,690 men aged 45-54 years from six countries studied between 1972 and 1989. The variation in the sex difference for HDL cholesterol was significant; the smallest difference (0.06 mmol/liter) was seen in China and the largest (0.40 mmol/liter) in Canada. Adjustment for differences in body mass index, smoking, alcohol use, and heart rate reduced but did not eliminate the variability. The sex difference in HDL cholesterol levels, usually assumed to be due to biologic factors, differs across cultures and may be related to environmental factors.

CHD and its risk factors in the People's Republic of China.

Mortality data obtained from the Health Statistics Office of the Ministry of Health, People's Republic of China (PRC), were compared to data for other countries taken from the World Health Statistics Annual. The crude death rate for coronary heart disease (CHD) in China in 1984 is estimated to be about one-tenth of that for North America and Australia. However, a high stroke to CHD ratio of about 5.0 was observed in China. The age-standardized CHD mortality rates were significantly higher for Beijing in north China than for Shanghai and Guangzhou in the south, and for urban than rural populations in all years from 1976 to 1986. Data on hospital admissions and autopsy material provide evidence for an increase in CHD incidence and prevalence in the last three to four decades. A low mean serum total cholesterol, related to a low habitual dietary intake of fat and cholesterol, is considered to be the main cause underlying low CHD mortality rates in China.

Risk factors for breast cancer in Chinese women of Beijing.

A self-administered questionnaire was completed by 497 Chinese women in Beijing with histologically confirmed breast cancer and by an equal number of age- and neighborhood-matched control women. High body weight (71 + kg) was a risk factor for breast cancer in women aged 50 + (RR = 1.90), but this effect did not quite reach statistical significance. Nulliparity and late age at first birth were associated with an elevated risk of breast cancer. In comparison to parous women who had their first child before age 20, those who delayed this event until after age 29 had an RR of 1.65. The comparable RR for nulliparous women was 3.72. Late age at menopause was a risk factor for breast cancer. The RR for menopause after age 50 compared to menopause before age 45 was 2.16. High parity and long duration of lactation were protective factors against breast cancer. These 2 factors were highly correlated with each other and also with age at first birth. The effect of each on breast cancer risk was somewhat reduced after adjustment for the other two. A personal history of benign breast disease (RR = 3.21) and a family history of breast cancer (RR = 2.17) were also associated with an increased risk of breast cancer.

Timed overnight sodium and potassium excretion and blood pressure in steel workers in North China.

Three timed overnight urinary sodium (Na), potassium (K) and creatinine measurements, standardized to 8 h, as well as three blood pressures on corresponding consecutive days were obtained on a sample of 90 steel workers (40 men, 50 women) aged 34-56 years in Beijing, North China. For three indices of electrolyte excretion - absolute Na and K output/8 h, Na:K ratio and 8 h creatinine output - the ratios of intra- to inter-individual variations were less than 1.0 for men, but higher for women in contrast to findings for U.S. population groups of similar age. This fact, probably reflecting greater stability of day to day electrolyte intake by Chinese than Americans, enables reasonably precise characterization of dietary electrolyte intakes of individual Chinese, particularly men, with only a few timed overnight urine specimens. With 3-day mean values for each person, nominally significant (i.e. not adjusted for multiple testing) positive simple correlations were found for urinary Na, Na:K and Na:creatinine with blood pressure [both systolic (SBP) and diastolic (DBP)] for men; and women for Na:K with SBP and DBP, but Na:creatinine with SBP only. With control for age, body mass index and pulse in multivariate analyses, only the relationship of Na:K and Na:creatinine to SBP and DBP remained significant for men; a similar, though less strong and consistent, trend was found for women, and K was inversely related to SBP for women. These data are consistent with an association between habitual intake of sodium and risk of hypertension, and also suggest that habitual potassium intake may have a countervailing influence in this regard.

Relationship between salt excretion and blood pressure in various regions of China.

Overnight urine samples were collected on three consecutive days from 3105 persons in 12 regions of China, and analysed for levels of sodium and potassium. The mean 9-hour overnight urine sodium level ranged from 49.51 to 139.12 mmol, and urine potassium from 6.32 to 18.43 mmol. Univariate regression, simple correlation analysis, and multivariate ridge regression analysis were carried out on the data. A positive correlation between blood pressure and urine sodium or sodium/potassium ratio was found in each of the twelve regions. Urine potassium showed a negative correlation with blood pressure in three regions.