Search PubMed⌕ Search

Biomedical subjects

Y C Deng

Publications and source records attributed to Y C Deng.

12 recordsLinked to original sources
PubMed1994

[Immunocytochemical study of mononuclear cells in peripheral blood and cerebrospinal fluid of patients with Japanese B encephalitis].

Using the technique of monoclonal antibody-immunogold-silver staining (M-IGSS), the mononuclear cells in peripheral blood (PB) and cerebrospinal fluid (CSF) were screened for immunoreactivity against JBE virus antigen (JBEV-Ag), interleukin-2 receptor (Tac), class II human leucocyte antigen (HLA-DR) and interferon-r (IFN-r) in 17 ELISA diagnosed JEB patients and 17 control cases with non-inflammatory and non-immunological diseases. It was found that JBEV-Ag+ cells were present in PB (16/17) and CSF (12/17) of the JBE group, but absent in both the control group and another 5 cases with mumps virus meningitis. The percentages of Tac+, HLA-DR+ and IFN-r+ cells in JBE patients were higher than those in controls.

Adolescent↗
PubMed1993

[Experimental studies on therapeutic effect of rat monoclonal antibody-bleomycin A6 conjugate against human colorectal cancer].

Bleomycin A6 (A6), a single component of bleomycin complex, is highly active against human colon and cecum cancer cells in vitro and xenografts in nude mice. R19, a rat monoclonal antibody against human cecum cancer Hce-8693 cells, was linked to A6. R19-A6 conjugate retained complete activity of McAb R19 and 10% activity of A6. As determined by clonogenic assay with human cecum cancer Hce-8693 cells for 1 hour exposure. The 50% inhibitory concentration (IC50) values for R19-A6, A6 and M3-A6 (conjugate of irrelevant Mc-A6) were 0.019, 1.05 and 1.00 mumol/L, respectively. The effect of the conjugate R19-A6 was 55-fold stronger than that of free A6 and 53-fold than irrelevant conjugate M3-A6. Clonogenic assay with human colon cancer HT-29 cells showed that the IC50 values were 0.078 mumol/L and 4.0 mumol/L for R19-A6 and free A6, respectively. The cytotoxicity to Hce-8693 and HT-29 cells was markedly blocked by unconjugated McAb R19 but not by irrelevant McAb MARK-3. The R19-A6 conjugate exerted 90% inhibition on the growth of cecum cancer Hce-8693 xenografts in nude mice, whereas equivalent doses of free A6, R19 plus A6 mixture and M3-A6 showed 52%, 34% and 48% inhibition, respectively. Histopathological examination showed no toxic changes in the heart, lung, liver, kidney and bone marrow in the R19-A6 conjugate treated animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Anthropomorphic dummy neck modeling and injury considerations.

This study investigates the modeling of the Hybrid III dummy head and neck system and its response under impulsive loading. Two neck models were proposed, one rigid, one flexible; both give satisfactory head kinematics upon comparing to minisled test results. The flexible neck model provides a more detailed understanding of the Hybrid III neck structure behavior. It indicates that the Hybrid III neck has a torque response similar to a human neck but has higher shear response. During flexion whiplash, the torque at the occipital condyle reverses its direction at about 25 ms after impact. Since concussion may be related to the head angular acceleration, which reaches its peak value in the first 25 ms, it might be necessary to extend the existing human torque-rotation corridor to include the neck response in this region. For flexion whiplash impact, simulation results indicated that the neck injury threshold is reached before exceeding the head injury threshold as the impact velocity is increased.

Acceleration↗
PubMed1987

Response of a human head/neck/upper-torso replica to dynamic loading--I. Physical model.

A human head/neck/upper-torso replica was constructed and instrumented and its response to impact and dynamic loading was studied. The model consists of a water-filled cadaver skull; plastic vertebrae, sternum and ribs; silicon rubber disks and ligaments; and fabric muscles. The static behavior of the system under sagittal plane and lateral loading was adjusted so as to correspond to that of cadaver behavior under similar loading. The structure was loaded impulsively by the sudden arrest of a supporting sled running on a track and by direct head impact with a suspended steel ball. The measured response included the head acceleration, the disk pressures, the muscle strains, the intracranial pressures and the skull strains; the sled motion was also monitored. These data were recorded with a microcomputer and oscilloscopes; the overall system deformation was observed by high-speed cameras. The muscle contraction effects were determined with the aid of microcomputer-controlled devices including a vacuum system, solenoid valves and plastic syringes.

Acceleration↗
PubMed1987

Response of a human head/neck/upper-torso replica to dynamic loading--II. Analytical/numerical model.

A three-dimensional lumped-parameter model of the human head/neck/upper-torso was developed to predict its motion for any specified initial conditions and that could also be used to compare with the results of other investigators. This model consists of ten rigid bodies representing the head, cervical vertebrae C1-C7, T1 and T2 combined with the rest of the torso. These rigid bodies were connected by intervertebral joints described by a stiffness matrix relating the force (moment) and translation (rotation). Fifteen pairs of muscles were incorporated in the model, represented by three-point linear elements with nonlinear constitutive relationships obtained from cadaver test results. The calculated response compared favorably with human volunteer data for both flexion and lateral whiplash. However, tests on an inanimate replica of a human indicated greater flexibility than predicted by the corresponding numerical model. The difference is believed to be due to insufficient mass of the muscles incorporated in the structure.

Acceleration↗
PubMed1984

Three-dimensional response of a lumped parameter head-neck model due to impact and impulsive loading.

A numerical procedure developed previously for predicting sagittal-plane motion of the human head-neck system due to impact and impulsive loading has been extended to three dimensions. In both situations, a lumped parameter approach is employed, but the current model lumps the mechanical response of each intervertebral joint into a single force-deformation relation evaluated from mechanical properties assembled by various investigators. Computations were performed to obtain the response of the model to a two-dimensional case of flexion whiplash, to one three-dimensional case of side impact to the skull and to another involving base acceleration normal to the sagittal plane. Agreement of the kinematic variables with the results of both the previous two-dimensional analysis and experimental data from a volunteer run is satisfactory, but somewhat poorer correspondence was found for the three-dimensional predictions upon comparison with data obtained from a physical model and from a volunteer when subjected to the prescribed loading. The differences in response are attributed to higher stiffness of facet separation of the model relative both to the structure and the volunteer, to insufficient damping, as well as to substantial differences in the mechanical deformation characteristic of the components of the prototypes and the numerical model.

Atlanto-Axial Joint↗
PubMed1980

The measurement of audiometric zero level of air conduction.

The audiometric zero level of air conduction for 100 healthy youths was determined over a frequency range from 20 Hz to 10 KHz in 1971-1973 under the laboratory conditions. The results obtained have been further verified recently on a selected group of 12 persons. This paper also presents the transfer experiments from the original earphone TDH-39(MX-41/AR) to six other types of earphones. The deviation of our data thus obtained from the recommendation by ISO is discussed.

Adolescent↗