Biomedical subjects
Publications and source records attributed to L Dai.
As a kind of anti-inflammatory protein fractionated and purified from the larva of parasa sinica, CCP (ip) has a significant anti-inflammatory effect on ear odema induced by croton oil in mice. Its ID50 is 1.6mg/kg, but a dose of 2.5mg/kg can also significantly inhibit the rat ankle odema induced by carrageenan and egg white.
Leaves and stem segments of Populus nigra were transformed with A. tumefaciens LBA4404 harboring a binary vector containing chimeric genes of NPT and 35S-omega-B.t. toxin-Nos. Nineteen regenerated kanamycin resistant plants were analyzed by DNA hybridization, out of which 10 were shown to be the candidates of transgenic plants. Insect tolerance tests showed that the transgenic plants were toxic to two lepidopteran pests, Lymantria dispar L. and Apocheimia cinerarius Erschoff. Based on the results of Southern blot of PCR products and the cluster analysis of their growth and insect resistance, three independent transgenic plants were selected, which were then propagated in the nursery field. This field test is currently in progress.
We have analyzed the risk factors of child bronchial asthma by a 1:1 matched case-control study. The results showed that the family hereditary history (OR = 44.44); the history of ingesting sensitizing foods (OR = 22.52) and of allergy (OR = 7.11) in maternal pregnancy; the history of allergy in childhood (OR = 9.27) and of respiratory diseases in infancy (OR = 7.71); the personality of child (OR = 8.01), the residential environment (OR = 9.08), and so on were the risk factors of child bronchial asthma. In addition, we have found that the age of the 1st onset of child bronchial asthma was associated with the following risk factors: the history of allergy in childhood and in maternal pregnancy, the family hereditary history and the residential environment, etc. It is confirmed that the child bronchial asthma is a multifactor disease.
A three-dimensional finite element model of the lumbar motion segment was developed to study the effect of disc degeneration upon stress distribution in the lumbar spine. The results showed that after degeneration of the intervertebral disc, the stress distribution and load transmission of the lumbar spine are significantly changed. It is concluded that these changes provide a biomechanical basis for understanding the etiology of spinal canal stenosis and nerve root entrapment.
In 142 strains of Staphylococcus aureus randomly isolated from clinical samples in a year, methicillin-resistant Staphylococcus aureus (MRSA) accounted for 79.6% (113/142). MRSA in the samples from the respiratory, burning and hematological departments came to 92.0% (23/25), 84.6% (11/13) and 83.3% (30/36) in proportion respectively. 79.6% of MRSA strains were isolated from the patients in whom the infections were confirmed to be hospital-acquired. All the strains of Staphylococcus aureus examined were resistant to penicillin G and ampicillin, but sensitive to vancomycin. Twenty hospital-acquired strains of MRSA showed a resistance to all detected antibiotics (multi-drug resistance, MDR), but vancomycin; strains of methicillin-sensitive ones, however, showed on MDR. In 45 strains of Staphylococcus aureus isolated from swabs of fingers of 62 medical workers, 31 (68.9%) were methicillin-resistant. The resistant similarity of shares of strains between medical staff and patients indicated a potential role that medical workers play in spread of nosocomial infections.
The stress distribution of the lumbar spine was analyzed with a mechanical model of the lumbar motion segment constructed by a three-dimensional finite element method, and the results were compared with the corresponding bone density represented by the value of CT. The results showed that the stress levels in the various parts of the lumbar spine were closely related to the CT values. The authors conclude that the dynamic balance of bone growth is maintained in large part by mechanical stress.
We have used a scanning near-field optical microscope to study the fluorescent light distribution in the near- and far-fields with two types of microdiscs, InGaP and GaN, fabricated in our laboratory. The InGaP microdisc has a radius of 2.5-5.0 microm, a thickness of 0.15-0.2 microm and a circular shape and the GaN disc has a radius of 5-8 microm with a thickness of 0.5-2 microm. Spontaneous emission enhancement in these microdiscs has been observed with emitting wavelengths of 650 and 550 nm respectively In both types of microdisc, the whispering-gallery mode (WCM) has been observed on the top surface using near-field optical and far-field microscopic methods. However, due to the different disc structures and optical confinements, the light distributions of the type types of disc are quite different. In the case of the InGaP disc, WGM is the dominant mode with a mixture of other modes. Interference-like ring intensities have been observed both inside the disc surface and outside, with a period ratio of 1:2. In addition, the propagating waves emitted from the side of the disc have been collected for the first time by using near-field optical microscopy. A theoretical calculation based on the theory of optical modes in microdisc lasers confirmed this observation. It also predicted the behaviour of the electric field distribution (transverse electric) inside and outside the disc, as well as the period of the wave propagation. In contrast, the near-field mapping of the GaN fluorescence showed not only a ring-like emission intensity along the circumference of the disc, an indication of WGM, but also an even intensity distribution inside the disc. This can be explained as the combination of the WGM with the Fabry-Perot mode of multi-reflection between the GaN layer and the substrate. The results also demonstrate the potential application of near-field optics to explore the light emission mode of a microdisc on a nanometre scale.
Human ASB-17 (Ankyrin Repeat and SOCS Box-containing 17) is a recently identified gene belonging to the ASB family, isolated from testis cDNA library. Human ASB-17 is expressed exclusively in testis among 16 tissues, revealed by Northern blot. Mouse Asb-17 was shown to be expressed from the third week post birth to adult by semi-quantitative RT-PCR analysis. In situ hybridization on frozen sections demonstrated that Asb-17 is expressed in spermatogenic cells in adult mouse, but not in Leydig cell and epididymis in adult mouse. ASB-17 proteins are highly conserved in mammals including human, mouse, rat, Canis familiaris and Macaca fascicularis.