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Biomedical subjects

L Q Xie

Publications and source records attributed to L Q Xie.

6 recordsLinked to original sources
PubMed2003

Enhancement of dissolved phosphorus release from sediment to lake water by Microcystis blooms--an enclosure experiment in a hyper-eutrophic, subtropical Chinese lake.

To clarify the possible influence of Microcystis blooms on the exchange of phosphorus (P) between sediment and lake water, an enclosure experiment was conducted in the hypereutrophic subtropical Lake Donghu during July-September 2000. Eight enclosures were used: six received sediment while two were sediment-free. In mid-August, Microcystis blooms developed in all the enclosures. There was a persistent coincidence between the occurrence of Microcystis blooms and the increase of both total P (TP) and soluble reactive P (SRP) concentrations in the water of the enclosures with sediments. In sediment-free enclosures, TP and SRP concentrations remained rather stable throughout the experiment, in spite of the appearance of Microcystis blooms. The results indicate that Microcystis blooms induced massive release of P from the sediment, perhaps mediated by high pH caused by intense algal photosynthesis, and/or depressed concentrations of nitrate nitrogen (NO3-N).

China↗
PubMed2001

[Effects of vitamin K on bone metabolism in tail-suspended rats].

Objective. To study the effects of vitamin K on bone metabolize in simulated weightlessness rats. Method. Male SD rats were divided into three groups (n = 9): the free active control (FAC), the tail-suspended control (SC), and the tail-suspended group treated with vitamin K (SVK) (50 mg/kg weight/d). The experiment lasted for 3 weeks. Bone biomechanical properties, bone mineral contents (BMC) and bone biochemical markers of bone metabolism were determined. Result. Compared with SC, total and bound bone gla protein (BGP) of serum, BMC of the femur and tibia, femoral mechanical properties, ALP activity of tibia all increased significantly; while NO content of femoral trunk decreased significantly. Conclusion. Vitamin K improved the bone metabolism and bone structure, decreased bone loss, increased bone biomechanical properties, decreased catagmatic fatalness. It proved that vitamin K prevented bone loss of simulated weightlessness rats.

Alkaline Phosphatase↗
PubMed2001

[Mechanotransduction in bone].

This article reviewed the progresses in the research of mechanisms of bone adaptation. The process of mechanotransduction can be divided into four distinct steps: mechanocoupling; biochemical coupling; transmission of signal; effector cell response. Through these four steps, the loads acting on the bones are transduced into biochemical signals, and then change the function of bone cells, finally induce the changes of bone structures to adapt the mechanical environment.

Adaptation, Physiological↗
PubMed1999

[Developments of the theory of skeletal adaptation to mechanical loading].

The primary mechanical function of bone is to provide rigid levers for limbs to act against mechanical loading and gravity, and to remain as light as possible to allow efficient locomotion. There are increasing evidence that mechanical loading is an important, if not the most important, factor influences bone mass and architecture. Many bones are exposed to thousands of repetitive loads every day, which always cause strains. Unusual strain distributions, high strains, and high strain rates seem to be particularly osteogenic. Bone modeling can increase bone strength and mass, bone remodeling can conserve or reduce them, and each can be turned ON or OFF in response to its own threshold range of bone strains. During growth and development, the skeleton optimizes its architecture and strength by (re)modeling to adapt to the largest voluntary loads on bones. The loads come from muscles, not body weight. A new standard of defining osteoporosis might relate bone strength to muscle strength that concerns the osteopenias pathogenesis and its severity, and it would be useful for prevention and cure of osteoporosis.

Aerospace Medicine↗
PubMed1989

A method for the indirect determination of trace bound selenomethionine in plants and some biological materials.

An indirect method for the determination of trace bound selenomethionine (SeMet) has been developed. SeMet reacts with cyanogen bromide (CNBr) quantitatively in the presence of SnCl2 to form CH3SeCN, and after extraction with CHCl3 is acid-digested to form Se(IV). Selenium(IV) reacts with 4-nitro-o-phenylenediamine reagent to form 5-NO2-piazselenol which is then determined by gas chromatography equipped with electron capture detector. The sensitivity of this method (CNBr-piazselenol-GC method) is 6 ng SeMet/g of sample. Trace-bound SeMet in plants and some biological materials has been successfully determined by this method and its content has been compared with the total selenium in the sample.

Animals↗