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Biomedical subjects

J X Li

Publications and source records attributed to J X Li.

At least 19 recordsLinked to original sources
PubMed2006

The duration and plantar pressure distribution during one-leg stance in Tai Chi exercise.

BACKGROUND: Tai Chi exercise improved the balance control and muscle strength of the lower extremities. The aim of this study is to quantify the one-leg stance duration and plantar pressure distribution during the one-leg stance in Tai Chi and to try to elaborate on its probable effects on the ability to balance on one leg. METHODS: Sixteen experienced Tai Chi practitioners participated in this study. The Novel Pedar-X insole system was used to record the plantar forces during the execution of a set of 42-form Tai Chi movements and during normal walking. The one-leg stance duration and plantar pressure distribution during the one-leg stance were analyzed. FINDINGS: In Tai Chi exercise, the total duration spent in the one-leg stance was less (p<0.05), the duration of each one-leg stance was longer (p<0.01) and the medial-lateral displacement of the centre of pressure was greater (p<0.05) than during normal walking. The peak pressure and pressure-time integral of the second and third metatarsal heads and the fourth and fifth metatarsal heads were significantly greater (p<0.05) than those of other plantar regions during the one-leg stance in normal walking, whereas the peak pressure and pressure-time integral of the first metatarsal head and the great toe were significantly greater (p<0.05) than those of other plantar regions during the one-leg stance in Tai Chi exercise. INTERPRETATION: The longer duration of each one-leg stance and the plantar pressure distribution characteristics during the one-leg stance in Tai Chi exercise may be associated with an improved ability to balance on one leg. The findings may provide useful information toward the development of strengthening programs, strategies for the prevention of falls, and the promotion of a physically active lifestyle.

Adult↗
PubMed2006

Effects of methionine and betaine supplementation on growth performance, carcase composition and metabolism of lipids in male broilers.

1. This study was conducted to investigate the effects of methionine and betaine supplementation on growth performance, carcase composition and lipid metabolism in growing broilers. 2. A total of 450 commercial broilers, 22 d of age, were randomly allocated to three groups, each of which included three replicates (50 birds per replicate). The groups received the same methionine-deficient diet supplemented with 0 or 1 g/kg methionine, or 0.5 g/kg betaine, respectively. 3. Methionine and betaine supplementation significantly improved weight gain and feed conversion. Supplemental methionine and betaine also significantly increased breast muscle yield and decreased abdominal fat content. Meanwhile, addition of methionine and betaine significantly increased the contents of creatine and free carnitine in liver, the activity of hormone-sensitive lipase in abdominal fat and the concentration of free fatty acid in serum, whereas uric acid concentration in serum was significantly decreased. 4. The results of this study suggest that betaine can spare methionine in its function as an essential amino acid and is as effective as methionine in improving performance and carcase quality of growing broilers if the diet is moderately deficient in methionine. The decrease in abdominal fat may be due to the increased carnitine synthesis in liver and hormone-sensitive lipase activity in abdominal fat.

Animal Feed↗
PubMed2006

Effects of long term Tai Chi practice and jogging exercise on muscle strength and endurance in older people.

OBJECTIVES: To investigate the influence of regular Tai Chi (TC) practice and jogging on muscle strength and endurance in the lower extremities of older people. METHODS: Twenty one long term older TC practitioners were compared with 18 regular older joggers and 22 sedentary counterparts. Maximum concentric strength of knee flexors and extensors was tested at angular velocities of 30 degrees/s and 120 degrees/s. Ankle dorsiflexors and plantar flexors were tested at 30 degrees/s and the dynamic endurance of the knee flexors and extensors was assessed at a speed of 180 degrees/s. RESULTS: The differences in the muscle strength of the knee joint amongst the three experimental groups were significant at the higher velocity. The strengths of knee extensors and flexors in the control group were significantly lower than those in the jogging group and marginally lower than those in the TC group. For the ankle joint, the subjects in both the TC and jogging groups generated more torque in their ankle dorsiflexors. In addition, the muscle endurance of knee extensors was more pronounced in TC practitioners than in controls. CONCLUSION: Regular older TC practitioners and joggers showed better scores than the sedentary controls on most muscle strength and endurance measures. However, the magnitude of the exercise effects on muscles might depend on the characteristics of different types of exercise.

Age Factors↗
PubMed2001

Tai chi: physiological characteristics and beneficial effects on health.

OBJECTIVES: To assess the characteristic effects of Tai Chi Chuan (TCC) exercise on metabolism and cardiorespiratory response, and to measure its effect on cardiorespiratory function, mental control, immune capacity, and the prevention of falls in elderly people. DESIGN: A review of controlled experimental studies and clinical trials designed with one of two aims: either to assess physiological responses during the performance of TCC or to assess the impact of this exercise on general health and fitness. MAIN OUTCOME MEASURES: Metabolic rate, heart rate, blood pressure, ventilation, maximal oxygen uptake (VO(2)MAX), immune capacity, falls, and fall related factors. SUBJECTS: A total of 2216 men and women. RESULTS: Under review were 31 original studies, published in Chinese or English journals, that met the criteria for inclusion. Most of the papers written in Chinese had not been introduced into the Western literature. Nine of these studies showed that TCC can be classified as moderate exercise, as its does not demand more than 55% of maximal oxygen intake. When this form of exercise and others conducted at equal intensity were compared, TCC showed a significantly lower ventilatory equivalent (VE/VO(2)MAX). Evidence provided by cross sectional and longitudinal studies suggests that TCC exercise has beneficial effects on cardiorespiratory and musculoskeletal function, posture control capacity, and the reduction of falls experienced by the elderly. CONCLUSIONS: TCC is a moderate intensity exercise that is beneficial to cardiorespiratory function, immune capacity, mental control, flexibility, and balance control; it improves muscle strength and reduces the risk of falls in the elderly.

Accidental Falls↗
PubMed2001

[Generation of Mx-cre transgenic mice].

To generate the transgenic mice expressing cyclization recombination enzyme, the recombinant gene, in which the coding region of cre gene is derived by the promoter of mouse Mx gene, was microinjected into pronuclei of fertilized mouse eggs. Founders of transgenic mice harbouring the recombinant gene were screened by polymerase chain reaction (PCR) at genomic DNA level and confirmed by Southern blot. One line of Mx-cre transgenic mice was obtained. Then, the Mx-cre transgenic mouse line was cultured and propagated.

Animals↗
PubMed2001

[Detection of Cre recombinase activity in Mx-Cre transgenic mice induced by INF in vitro].

The Cre recombinase and its activity in C57-TgN(Mx-Cre) transgenic mice is studied by polymerase chain reaction (PCR), Western blot, immunohistochemistry, immunogold electron microscopy and Southern blot. C57-TgN(Mx-Cre) transgenic mice harbouring cre gene in genomic DNA is demonstrated by PCR, and these mice which are induced by INF-alpha 1b could express Cre recombinase, which is confirmed by Western blot. With immunohistochemistry, we find that the Cre recombinase expresses in hepatocyte cytoplasm and nuclear of C57-TgN(Mx-Cre) transgenic mice. Cre recombinase expressed in hepatocyte cytoplasm and nuclear is further confirmed by immunogold electon microscopy. And it is supported that the Cre recombinase which is created from C57-TgN(Mx-Cre) transgenic mice induced by INF-alpha 1b can direct DNA recombination reaction in vitro. All evidence leads us supporting the view that the Cre recombinase expressed in C57-TgN(Mx-Cre) transgenic mice has activity. Thus we find a method to detect the activity of Cre recombinase in vitro.

Animals↗
PubMed2001

[Linkage analysis and mutation detection of GRIA3 in Smith--Fineman--Myers syndrome].

To determine the role of GRIA3 in the etiology of Smith--Fineman--Myers syndrome (SFMS), polymorphic short tandem repeats within GRIA3 gene were genotyped by PCR and denaturing polyacrylamide gel electrophoresis to test linkage between GRIA3 and the gene responsible for SFMS. The open reading frame of GRIA3 was detected for mutation by PCR amplification and direct sequencing in affected and normal males from SFMS family. One of the two short tandem repeats was informative in SFMS family. Tight linkage between SFMS locus and GRIA3 gene was established by STR3 within GRIA3 gene. No disease--causing mutation was found within the open reading frame of GRIA3 gene. The disease in SFMS family from Shandong (China) is not caused by the mutation within open reading frame of GRIA3 gene.

Abnormalities, Multiple↗
PubMed2001

[The presentation of neo gene in chimeric mice obtained from ES cells].

To explore the potentiality of the mouse ES cell line which is employed in our laboratory were transfected with neo gene and selected with G418. Some ES cell clones expressing neo gene were obtained. After ES clones were picked up and expanded, the ES cells were mircoinjected into blastocysts and implanted miceuterus. 60 blastocysts were implanted into 5 mice. Finally, 3 chimeric mice with neo gene were born. PCR was carried out to analyze the presentation of neo gene in tissues of chimeric mice. The results showed that many tissues harbored the neo gene, including skin, liver and blood et al.

Animals↗
PubMed2001

[Clinical study on analgesic mechanism of bitongxiao in treating neck pain due to cervical spondylitis].

OBJECTIVE: To study the analgesic mechanism of Bitongxiao (BTX, a Chinese herbal decoction) in treating neck pain due to cervical spondylitis (CS). METHODS: BTX and Jingfukang (JFK) granule were used to treat the treated and the control group separately in 102 CS cases. Plasma leucine enkephalin (LEK), substance P (SP) and prostaglandin E2 (PGE2) before and after treatment were assayed by radioimmunoassay (RIA). RESULTS: Twelve patients in the treated group were clinically cured, 36 markedly effectively, 3 effectively and 1 ineffectively, while in the control group they were 5, 33, 14 and 0 cases respectively. The cured and marked effective rate in the treated group was 92.3%, while that in the control group 72.0%. After treatment the pain score (VAS) of both groups were significantly reduced, but the reduction was higher in the treated group than that in the control. Before treatment, plasma LEK in all patients was abnormally low, but after treatment, it raised obviously more in the treated group than that in the control (P < 0.05). Plasma SP of both groups were obviously elevated, and PGE2 revealed unaltered after treatment. CONCLUSION: BTX has strong, fast-acting and long-lasting analgesic effect with no side-effects, it could elevate the lowered plasma LEK level in cervical spondylitis patients and increase plasma SP level. The analgesic mechanism of BTX might be associated with its effect on LEK, SP or other endorphins, directly acting on the pain modulation system.

Adult↗
PubMed2001

[The analgesic and antispasmodic effects of guang tong xiao aerosol of TCM].

OBJECTIVE: To observe the analgesic and antispasmodic effects of Guang Tong Xiao Aerosol (GTXA). METHOD: Writhing test and tail-flick of physical stimulation were made to study the analgesic effect on mice and rats. RESULT AND CONCLUSION: GTXA given by gastrogavage in dose of 18.75 g.kg-1 or 12.50 g.kg-1 could markedly raise the pain threshold after chemical stimulation in mice and physical stimulation in rats, and had antispasmodic effects.

Aerosols↗
PubMed2000

[The efficacy of the native flumazenil for acute poisoning with benzodiazepines].

OBJECTIVE: To evaluate the efficacy of the native flumazenil for acute self-poisoning with benzodiazepines. METHODS: One hundred and twenty-six patients with unconsciousness from benzodiazepines-induced self-poisoning were randomly divided into two groups: flumazenil group(Group II, 63 cases) were treated with flumazenil, and conventional-medicine group(Group I, 63 cases) with placebo(glucose, vitamin C, KCl). A modified Glasgow Coma Scale(MGCS) and Observer's Assessment of Alertness/Sedation Scale(OAA/S) were used in the assessment of consciousness. RESULTS: MGCS were increased by 5.3, 8.0, 9.4 and 7.3 at 15 min, 30 min, 60 min and 180 min after intravenous flumazenil(P < 0.01) and by 5.2, 7.7, 8.7 and 6.9 in comparison with conventional-medicine group(P < 0.01). OAA/S increased by 1.9 compared with conventional-medicine group(P < 0.01). No severe side-effects were found in the treatment. CONCLUSIONS: Flumazenil might improve benzodiazepines-induced unconsciousness markedly and may be the most effective antagonist of benzodiazepines.

Adolescent↗
PubMed2000

Characterization of wet masses of pharmaceutical powders by triaxial compression test.

The mechanical and rheologic properties of wet masses of pharmaceutical powders determine their processibility and the quality of the product prepared by extrusion/spheronization. In this work, a triaxial compression test was attempted for the first time to characterize material properties of pharmaceutical wet masses of different hydrophilicity and particle sizes. The stress-strain curves and the pore pressure were determined at various cell pressures. The failure criteria of the wet masses were obtained from the stress path on the deviator stress plane. The cohesion (c) and the angle of internal friction (phi) were evaluated from the intercept and the slope of the failure loci. The stress-strain behavior strongly depended on the type of powders and cell pressure. The values of c and phi were similar for wet masses of EC FP, MCC PH101, and SMCC 50, but a very small phi and a very high c value for HPMC. The shear strength and rigidity of the wet masses were in the order of EC FP > SMCC 50 > MCC PH101 > HPMC, whereas the elastic recovery was in the opposite order. These material parameters could be used as references for selection of excipients and formulation for extrusion/spheronization.

Cellulose↗
PubMed2000

Phenylpropanoid glycosides from Smilax glabra.

Five phenylpropanoid esters of sucrose glycosides, trivially named smiglasides A-E, were isolated from the rhizomes of Smilax glabra. Their structures were elucidated on the basis of spectroscopic studies.

Benzene Derivatives↗
PubMed2000

Effects of load carriage on heart rate, blood pressure and energy expenditure in children.

Fifteen male primary school children, aged 10 years, were selected to carry school bags of 10, 15 and 20% of their own body weights, where 0% body weight was used as a control. Maximum oxygen uptake (VO2max) tests were conducted on a motorized treadmill using a continuous incremental protocol. During the load carrying test, subjects walked on a treadmill at 1.1 m s(-1) for 20 min at each load condition. Blood pressures were measured before, immediately following, and at 3 and 5 min after every trial. Heart rate and expired VO2 were recorded before, during and 5 min after walking using a cardiopulmonary function system. The results showed a significant difference in oxygen uptake, energy expenditure and the recovery of blood pressure rise for between 10 and 20% body weight load conditions. The carrying weight of a school bag for children could be recommended as 10% of body weight because it was not significantly different from 0% load in the metabolic cost.

Biomechanical Phenomena↗
PubMed2000

Balance control, flexibility, and cardiorespiratory fitness among older Tai Chi practitioners.

BACKGROUND: Tai Chi Chuan (TTC) exercise has beneficial effects on the components of physical condition and can produce a substantial reduction in the risk of multiple falls. Previous studies have shown that short term TCC exercise did not improve the scores in the single leg stance test with eyes closed and the sit and reach test. There has apparently been no research into the effects of TCC on total body rotation flexibility and heart rate responses at rest and after a three minute step test. METHODS: In this cross sectional study, 28 male TCC practitioners with an average age of 67.5 years old and 13.2 years of TCC exercise experience were recruited to form the TCC group. Another 30 sedentary men aged 66.2 were selected to serve as the control group. Measurements included resting heart rate, left and right single leg stance with eyes closed, modified sit and reach test, total body rotation test (left and right), and a three minute step test. RESULTS: Compared with the sedentary group, the TCC group had significantly better scores in resting heart rate, three minute step test heart rate, modified sit and reach, total body rotation test on both right and left side (p < 0.01), and both right and left leg standing with eyes closed (p < 0.05). According to the American Fitness Standards, the TCC group attained the 90th percentile rank for sit and reach and total body rotation test, right and left. CONCLUSION: Long term regular TCC exercise has favourable effects on the promotion of balance control, flexibility, and cardiovascular fitness in older adults.

Accidental Falls↗
PubMed2000

[Expression of 3'-truncated preS/S gene in transgenic mice].

The 3'-truncated preS/S region from HBV genome, encoding a transcriptional transactivator, was cloned and a recombination expression vector for 3'-truncated HBV preS/S sequences under the control of the CMV promoter was constructed by recombination DNA techniques. Then, the expression vector DNA was microinjected into pronuclei of fertilized mouse oocytes. Founders of transgenic mice harbouring the recombination gene which can be expressed were screened by polymerase chain reaction (PCR) at genomic DNA level and confirmed by ELISA andlysis at protein level. Two of 15 mice in one series of microinjections showed the expression of 3'-truncated preS/S gene from HBV genome. The expression vector of 3'-truncated preS/S gene might be helpful for further studies of relationship between the expression production of 3'-truncated preS/S sequence and HBV-associated oncogenesis in vitro. The transgenic mice with expressing 3'-truncated preS/S gene will provide new insight into its roles in the development of human hepatocelluar carcinoma (HCC) in vivo.

Animals↗