PubMed Health⌕ Search

Biomedical subjects

Y H Li

Publications and source records attributed to Y H Li.

At least 19 recordsLinked to original sources
PubMed2006

Novel self-aggregates of chitosan oligosaccharide grafted stearic acid: preparation, characterization and protein association.

A novel hydrophobically modified chitosan oligosaccharide (CSO) containing 5.4 stearic acid (SA) groups per 100 anhydroglucose units was synthesized by an 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-mediated coupling reaction. The purified copolymer was structurally characterized by IR spectroscopy. Characteristics of self-aggregates of the amphiphilic copolymers were studied by fluorescence spectroscopy and dynamic light scattering. The critical aggregation concentration (cac) value of the self-aggregates in aqueous solution was determined by measuring the fluorescence intensity of pyrene as a fluorescent probe. Mean diameter of self-aggregates in pH 7.0 PBS was 25.0 +/- 14.7 nm with a unimodal size distribution. The diameter, as well as the zeta potential of self-aggregates increased when the pH value of dispersion medium decreased. Bovine serum albumin (BSA) was further enveloped in the interface of different single self-aggregate and formed nanoparticles. The size of BSA-loaded stearic acid modified CSO nanoparticles depended on the pH values of the dispersed aqueous vehicle, and the size diminished when the pH values of the dispersed aqueous vehicle decreased, whilst, the BSA encapsulation efficiency enhanced. The nanoparticles were characterized by Transmission Electron Microscopy (TEM). BSA release from stearic acid modified CSO nanoparticles decreased when the pH values of the delivery media decreased, in the range from 7.2 to 5.8.

Chitosan↗
PubMed2005

Effects of nitrogen deficiency on photosynthetic traits of maize hybrids released in different years.

BACKGROUND AND AIMS: New maize (Zea mays) hybrids outperformed old ones even at reduced N rates. Understanding the mechanisms of the differences in performance between newer and older hybrids under N deficiency could provide avenues for breeding maize cultivars with large yield under N deficiency, and reduce environmental pollution caused by N fertilizers. METHODS: N deficiency effects on grain weight, plant weight, harvest index, leaf area and photosynthetic traits were studied in the field for six maize hybrids released during the past 50 years to compare their tolerance and to explore their physiological mechanisms. KEY RESULTS: N deficiency decreased grain yield and plant weight in all hybrids, especially in the older hybrids. However, there was no significant difference in harvest index, rate of light-saturated photosynthesis (Psat) 20 d before flowering, leaf area or plant weight at flowering between the N-deficient and control plants of all hybrids. Dry matter production after flowering of the N-deficient plants was significantly lower than that of the control plants in all hybrids, especially in the older hybrids, and was mostly due to differences in the rate of decrease in photosynthetic capacity during this stage. The lower Psat of the older hybrids was not due to stomatal limitation, as there was no significant difference in stomatal conductance (gs) and intercellular CO2 concentration (Ci) between the hybrids. N deficiency accelerated senescence, i.e. decreased chlorophyll and soluble protein contents, after anthesis more for the earlier released hybrids than for the later ones. N deficiency decreased phosphoenolpyruvate carboxylase (PEPCase) activity significantly more in older hybrids than newer hybrids, and affected the maximal efficiency of PSII photochemistry (Fv/Fm) only in the old hybrids and at the late stage. CONCLUSIONS: Compared with older (earlier released) hybrids, newer (later released) hybrids maintained greater plant and grain weight under N deficiency because their photosynthetic capacity decreased more slowly after anthesis, associated with smaller non-stomatal limitations due to maintenance of PEPCase activity, and chlorophyll and soluble protein content.

Carbon Dioxide↗
PubMed2005

High-dose glucose-insulin-potassium treatment reduces myocardial apoptosis in patients with acute myocardial infarction.

BACKGROUND: Several clinical trials have suggested that a metabolic cocktail of glucose-insulin-potassium (GIK) decreases mortality rates in patients with acute myocardial infarction (AMI). It has also been reported that Fas-mediated apoptosis plays an important role in ischaemic/reperfusion injury in the rat model. This study was designed to evaluate the interaction of ischaemic/reperfusion and reperfusion therapy coadministered with high-dose GIK treatment on soluble Fas/APO-1 (sFas) and Fas ligand (sFasL) plasma concentration in patients with AMI. MATERIALS AND METHODS: Seventy-four patients presenting with AMI who underwent reperfusion therapy were randomized into a GIK group (n = 35) receiving high-dose GIK for 24 h or a vehicle group (n = 39). Thirty-four control subjects were also enrolled in the present study. Strepavidin-biotin ELISA was used to determine the soluble sFas and sFasL plasma concentration at baseline, 24 h (h), 3 day (d), 7 d and 14 d. RESULTS: Soluble Fas and sFas-L serum concentrations ([sFas] and [sFas-L]) of patients with AMI were significantly elevated at baseline as compared with normal controls (NCs; P < 0.01 vs. NC). The sFas in the GIK and vehicle groups markedly decreased 24 h after the GIK infusion (10.7-->5.9 ng mL(-1) and 9.7-->6.5 ng mL(-1); P < 0.01 vs. baseline) and then increased during the 3-7-d period (5.9-->12.1 ng mL(-1) and 6.5-->11.1 ng mL(-1); P < 0.01 vs. 24 h). The GIK group demonstrated reduced sFas (12.1-->5.9 ng mL(-1)) at 14 d (P < 0.01 vs. 7 d), with no concomitant changes in the vehicle group. The sFas-L in the GIK and vehicle groups was not significant different during the 14-d period. CONCLUSIONS: These results indicate that the sFas and sFasL in patients with AMI increased significantly compared with NC. Owing to the cardioprotective effects reported here and by others, a high-dose GIK infusion co-administered with the timely re-establishment of nutritive perfusion should be strongly considered as a treatment of choice for AMI. Additionally, sFas may be a valuable marker of the physiological response to ischaemic/reperfusion injury and reperfusion associated with high-dose GIK treatment.

Aged↗
PubMed2005

Influence of hydroxyethyl starch on lipopolysaccharide-induced tissue nuclear factor kappa B activation and systemic TNF-alpha expression.

BACKGROUND: Several studies have shown beneficial effects of hydroxyethyl starch (HES) on organ damage in the treatment of severe inflammatory situations, but the mechanisms remain unclear. Nuclear factor-kappa B (NF-kappaB) activation is known to contribute to many aspects of inflammatory injury and organ dysfunction in critical illness, and tumor necrosis factor-alpha (TNF-alpha) is considered the most important pro-inflammatory cytokine. The present study was undertaken to test whether HES (200/0.5) has some effects on tissue NF-kappaB activity and systemic TNF-alpha expression induced by lipopolysaccharide in order to define a possible mechanism of the beneficial effects of HES. METHODS: Male Wistar rats were randomly divided into seven groups treated with saline, lipopolysaccharide (LPS, 6 mg/kg), LPS plus HES (3.75, 7.5, 15, 30 ml/kg), or HES (30 ml/kg) alone. Two hours after LPS challenge, NF-kappaB activation in the lungs, hearts, livers, and kidneys were examined with an electrophoretic mobility shift assay. Four hours after LPS challenge, plasma TNF-alpha concentrations were measured using an enzyme-linked immunosorbance assay. RESULTS: 3.75 and 7.5 ml/kg HES suppressed LPS-induced NF-kappaB activation in the four tissues and decreased plasma TNF-alpha elevation. The effects of 15 ml/kg HES was only significant in inhibiting NF-kappaB activity in the lung and liver. No effect of 30 ml/kg HES was revealed in all the cases. CONCLUSION: Lower doses of HES may inhibit tissue NF-kappaB activation and systemic TNF-alpha elevation after LPS challenge, which might be helpful during sepsis.

Animals↗
PubMed2005

Radiographic assessment of congenital talipes equinovarus: strapping versus forced dorsiflexion.

PURPOSE: To compare 2 radiographic assessment methods for congenital talipes equinovarus: strapping the ankle with tapes versus dorsiflexion with a wooden block. METHODS: Anteroposterior and lateral radiographs were taken with the ankle strapped by tapes or dorsiflexed by a wooden block. Talocalcaneal and tibiocalcaneal angles were measured and analysed. RESULTS: 20 radiographic assessments were performed on 14 patients. From the anteroposterior view, the mean talocalcaneal angle with strapping was 19.4 degrees (range, 0-34.0 degrees; standard deviation [SD], 11.2 degrees). From the lateral view, the mean talocalcaneal angle with strapping was 22.0 degrees (range, 8.0-38.8 degrees; SD, 8.9 degrees) and with forced dorsiflexion was 21.0 degrees (range, 0-52.7 degrees; SD, 11.3 degrees), with a mean absolute difference of 9.4 degrees between the 2 groups. The mean tibiocalcaneal angle with strapping was 77.9 degrees (range, 43.2-120.0 degrees; SD, 18.8 degrees) and with forced dorsiflexion was 78.2 degrees (range, 29.5-134.0 degrees; SD, 24.7 degrees), with a mean absolute difference of 15.7 degrees between the 2 groups. The difference between the tibiocalcaneal measurements in the 2 groups was statistically significant (p=0.026). CONCLUSION: Similar results were obtained for talocalcaneal and tibiocalcaneal angles measured with strapping and forced dorsiflexion. However, the strapping method provides better stabilisation while radiographs are taken.

Clubfoot↗
PubMed2005

Diffuse idiopathic skeletal hyperostosis with cervical spinal cord injury -a report of 3 cases and a literature review.

INTRODUCTION: Diffuse idiopathic skeletal hyperostosis (DISH), though common, is often asymptomatic. However, spinal hyperostosis can predispose the affected to chronic myelopathic symptoms and acute spinal cord injury. CLINICAL PICTURE: We report on 3 patients with DISH, who sustained traumatic cervical cord injuries. Two were tetraplegic at presentation. The radiologic findings of the patients are also discussed. TREATMENT: Both the tetraplegic patients were treated non-surgically in view of high surgical risk. OUTCOME: Both the tetraplegic patients died due to mechanical respiratory failure. CONCLUSIONS: The potential catastrophic neurological sequelae of DISH from relatively minor trauma must be understood. Further studies are needed to aid in evidence-based clinical management of asymptomatic patients with DISH.

Aged↗
PubMed2004

Biomechanical and electromyographic evaluation of ankle foot orthosis and dynamic ankle foot orthosis in spastic cerebral palsy.

This study evaluated the biomechanical and electromyographic effects of conventional ankle foot orthoses (AFOs) and dynamic ankle foot orthoses (DAFOs) on gait in patients with spastic cerebral palsy (CP). Thirteen patients with dynamic equinus underwent motion analysis with electromyography. Both AFOs and DAFOs provided longer stride length, permitted pre-positioning for initial contact, and successfully controlled the excessive plantarflexion during the swing phase. Median frequency (MF) of EMG signal indicated that extremely high firing was found in the patient's lower limbs compared to controls that resulted in tiredness. The DAFOs allowed a significantly larger total ankle range of motion than the AFOs. However, AFOs significantly reduced the MF while DAFOs did not. The reduced MF seen when wearing AFOs suggested an improvement of walking endurance. The DAFO had the advantage of less restriction on ankle movement, which avoids muscular atrophy and improves orthotic compliance.

Ankle Joint↗
PubMed2004

Dielectric analysis of nanofiltration membrane in electrolyte solutions: influences of electrolyte concentration and species on membrane permeation.

Dielectric properties of a nanofiltration membrane immersed in dilute aqueous electrolyte solutions were measured, and frequency dependence of capacitance and conductance of the systems was analyzed, based on the interfacial polarization theory, giving values of permittivity and conductivity of the membrane and the solutions. Permittivity, epsilon m, of the membrane slightly decreased whereas conductivity, km, of the membrane increased with increasing electrolyte concentration, as a result of entrance of ions into the membrane. The ratio of membrane/solution conductivity, km/kw, also depended on the electrolyte concentration, showing that distribution of ions in the membrane and in solutions follow Donnan equilibrium, due to the presence of negative fixed charges in the membrane. New expressions were derived from Donnan equilibrium principle to explain this phenomenon, and negative fixed charge concentration ce of the membrane was obtained; thus the Donnan potential, DeltaPhi Don, of the membrane in solutions at various concentrations could be calculated. The new expressions could be expected to be usable to analyze ion permeation property through membrane.

Journal Article↗
PubMed2004

Localization of angiotensin II in pig ovary and its effects on oocyte maturation in vitro.

The renin-angiotensin system (RAS) has been found in mammalian ovarian tissue; however, its physiological role is unclear. This study examined the content of angiotensin II (Ang II) in porcine follicular fluid (pFF), Ang II localization and its receptors in ovary, and the effects of Ang II on porcine oocyte maturation. The concentrations of Ang II were 6951.82 +/- 1295.83, 3502.99 +/- 679.10, 3147.89 +/- 690.60, and 2545.92 +/- 407.01 pg/ml in pFF from small, medium, large, and extra-large follicles, respectively. In addition, Ang II was found on zona pellucidae (ZP) and granulosa cells by immunoreactive staining. The distribution of AT1, an Ang II receptor subtype, was in accordance with that of Ang II. However, AT2, another Ang II receptor, was mainly distributed in the stroma and thecal layers of follicles. When oocytes were cultured in media containing various concentrations of Ang II, a higher (P<0.05) proportion of oocytes reached metaphase II (MII) in the medium with 100 ng/ml (87.0%) than without Ang II (61%). When oocytes from different sizes of follicles were separately cultured in media containing 100 ng/ml Ang II, maturation rates were significantly higher in oocytes from small (61.5%) and medium (85.1%) follicles than that of their controls (45.1 and 72.6%, respectively). However, addition of Ang II inhibited nuclear maturation in oocytes from large follicles (77.8% versus 87.3%). Fertilization and male pronuclear (MPN) formation rates of oocytes matured in medium containing 100 or 1000 ng/ml of Ang II were higher (P<0.05) than that of oocytes matured in medium containing 0 or 10 ng/ml Ang II. Glutathione content in oocytes cultured for 44 h in medium containing 100 or 1000 ng/ml of Ang II was also higher (P<0.01) than that of oocytes cultured in medium containing 0 or 10 ng/ml Ang II. In conclusion, Ang II was present in porcine ovaries and may regulate follicle growth and oocyte maturation.

Angiotensin II↗
PubMed2004

Pathogenesis of jumping translocations: a molecular cytogenetics study.

BACKGROUND/AIMS: Jumping translocations are rare cytogenetic aberrations in haematological malignancies, the pathogenesis of which remains to be fully characterised. We investigated the mechanism of formation of jumping translocations in a case of adult common acute lymphoblastic leukaemia (ALL) positive for the Ph translocation. METHODS: Interphase and metaphase fluorescence in situ hybridisation (FISH) was performed using several probe systems. Results were correlated with findings on conventional cytogenetics. Granulocytes, T-cells and leukaemic B-cells in peripheral blood were sorted by immunomagnetic method and the terminal restriction fragment (TRF) length of these cellular populations was determined by Southern blot analysis. RESULTS: Duplicated BCR-ABL fusion signals were found on a dic(14;22)der(22)t(9;22) chromosome. Clonal jumping translocations, existing as evolutionary changes, involved the donor chromosomal segment distal to 1q12 jumping onto the telomere ends of 11q, 15p, 19p and 20p. Telomere length was decreased in the neoplastic B-cell population and contributed to the formation of the dicentric chromosome that showed absence of telomere repeats at fusion ends. Subsequent pericentromeric heterochromatin decondensation of chromosome 1q occurred, and this donor segment was randomly fused to the shortened telomere ends of non-homologous chromosomes. CONCLUSIONS: Both telomere shortening and pericentromeric heterochromatin decondensation contribute to the formation of jumping translocations, which is most probably a multi-stage process.

Antigens, CD↗
PubMed2004

Rat model of orthotopic gastric transplantation.

INTRODUCTION: We tried to find a better surgical procedure of reconstruction after total gastrectomy. Seventy rats were operated to establish a model of orthotopic gastric transplantations which may also be important for abdominal multivisceral transplantation. OBJECTIVE: To establish a rat model of orthotopic gastric transplantation. METHODS: In the donor operation; after the spleen was resected and the proper hepatic artery ligated, the stomach was infused with cold (0 degrees C to 4 degrees C) sodium lactate Ringer's solution via the aorta. The stomach was resected with its peripheral blood vessels-the celiac trunk, the left gastric artery, the splenic artery, the common hepatic artery, the gastroepiploic artery, and the portal vein. In the recipient operation; after the stomach and the spleen were resected, the donor stomach was implanted. An end-to-side anastomosis was performed for the portal veins. After the end-to-end anastomosis between the donor celiac trunk and the recipient left gastric artery, the blood flow was opened. Then the anastomoses of the duodenum, and donor cardia to the recipient esophagus were performed in end-to-end style. RESULTS: Thirty five operations were performed, in which the success rate in the last 20 cases was 80% (16/20). The average operative time was 2.35 hours. The longest survival time was over 3 months. CONCLUSION: A rat model of orthotopic gastric transplantation was successfully established and provides a method to study abdominal multivisceral transplantation. It also provides a new way for reconstruction after the total gastrectomy.

Animals↗
PubMed2004

Non-traumatic acute paraplegia caused by cervical disc herniation in a patient with sleep apnoea.

A 57-year-old man with obstructive sleep apnoea presented with acute progression of myelopathy into paraplegia resulting from cervical disc herniation at C4-C5 and C5-C6 levels. There was no associated history of trauma. Rapid progress to paraplegia from non-traumatic cervical disc herniation rarely occurs. Diagnostic and treatment modalities are discussed. The possible relationship between cervical myelopathy and sleep apnoea is also discussed.

Acute Disease↗
PubMed2003

Glove punctures in orthopaedic surgery.

From February 2001 to May 2001, 792 latex gloves used in 100 operations from three orthopaedic sub-specialties (paediatrics, hand and spine) were tested for puncture by a water infusion test. Sixty-nine gloves from 45 operations were punctured, giving an overall glove perforation rate of 8.7% (69/792) and an operative perforation rate of 45% (45/100). The hand operations had the lowest operative perforation rate (19.4%) while the spine operations had the highest (63.6%). The glove perforation rate increased in bony procedures (60% versus 22.5%), in procedures with major instrumentation (66% versus 18%) and in more lengthy procedures. The thumbs and the left index finger had more punctures than other parts. In addition, the glove perforation rate for single gloving was 9.6% (53/552) while that for the inner glove of double gloving was 0.8% (1/120). Based on these findings, we would like to recommend double gloving and regular glove changing in these high-risk surgeries.

Equipment Failure↗
PubMed2003

Removal of fluoride from water by carbon nanotube supported alumina.

This paper describes a new adsorption material carbon nanotube supported alumina, used for fluoride removal from water. The effects of calcination temperature, alumina loading and pH on fluoride removal capacity were investigated. The optimum calcination temperature for preparing the adsorbents is 450 degrees C and the largest adsorption capacity takes place at alumina loading of 30 wt%. The broad pH range of 6.0-9.0 with high adsorption capability suggests that carbon nanotube supported alumina have great potential applications in practice. The adsorption data at different pH were well fitted to the Freundlich isotherm. The kinetic studies show that the adsorption reaction of fluoride removal by carbon nanotube supported alumina can be described by a second orderrate equation.

Adsorption↗
PubMed2002

Patterns of lung function in asymptomatic nonsmoking men and women in the People's Republic of China.

PURPOSE: To evaluate patterns of lung function in healthy, working Chinese men and women in different geographic areas of the People's Republic of China (PRC). METHODS: We conducted lung function tests on 2926 asymptomatic, never smoking Chinese men and women aged 35-56 years residing in or around Beijing and Guangzhou. Within each of these locations, separate urban and rural samples were recruited. RESULTS: Age and height adjusted lung function was greater in Beijing than in Guangzhou, and within each city for residents of rural vs. urban areas. Among women, estimated rates of lung aging were greater in Beijing than in Guangzhou, and in urban vs. rural areas. Both FEV(1) and FVC exhibited a curvilinear association with body mass index. CONCLUSIONS: Lung function data from this largely working cohort exhibited marked geographic and urban-rural differences in this never smoking, adult Chinese cohort. Such variation is not uncommon and may reflect differences in body size, diet, and environmental and occupational exposures across these different settings. Caution should be used in applying published reference equations to populations from different parts of the PRC.

Adult↗
PubMed2002

Preparation and identification of specific and high-affinity monoclonal antibodies against morphine.

A C6-hemisuccinate derivative of morphine was prepared and conjugated to bovine serum albumin and ovalbumin. High titer antibody producing spleen cells were removed and fused with myeloma cells of SP2/0 origin. Using a conventional immunization protocol generated twenty-six stable murine monoclonal antibodies (MAbs) producing cell lines to morphine. The donor mouse produced antiserum with a high titer of 1/640,000. Twelve MAbs were selected for further characterization since they showed high sensitivities (53 pg/well to inhibit 50% of the tracer) in improved group-selective immunoassay (IGSI). The assay, which maintains high sensitivity, high precision, and a wide range of optical density (OD) values, was developed using the conjugate M-6-S-OVA to screen and characterize the anti-morphine MAbs. After four successive limiting dilutions, antibodies produced by 12 clones had high affinities ranging from 10(9) to 10(10) M(-1). These clones were found to be of Ig(G) class and IgM class with kappa and lambda light chain. Subclass determination showed that the clones produced IgG1, IgG2a, IgG3, and IgM types of antibody. One clone (2F8B11F2A12) was used to establish the calibration curve with a sensitivity of 400 pg/mL covering up to 25.6 ng/mL in urine.

Animals↗