Biomedical subjects

C Deng

Publications and source records attributed to C Deng.

121 records · Page 7Linked to original sources

PubMed1993

[A report on investigation of an outbreak of Legionnaires' disease in a hotel in Beijing].

During the period from February to March, 1992, an outbreak of upper respiratory infection (influenza-like syndrome) took place in a hotel in Beijing. An epidemiological investigation and bacteriological examination were carried out in this hotel. The results showed that it was an outbreak of Legionnaires' disease caused by Legionella pneumophila serogroup 10 (Lp10): The incidence was 13.51% (5/37). This is the first report on LP10 infection in China.

Adult↗

PubMed1992

Overlap of somatic and visual response areas in the Wulst of pigeon.

The somatic and visual response areas of the Wulst were investigated electrophysiologically in pigeons. Somatosensory neurons are distributed in the hyperstriatum accessorium (HA), the hyperstriatum intercalatus superior (HIS) and the hyperstraitum dorsal (HD), mainly in HA. The radial nerve response area is relatively larger and overlaps the sciatic nerve area. Visual neurons are located in HA, especially the more superficial part of HA. In the Wulst, the somatic response area overlaps the visual area and there is somatosensory-visual convergence.

Animals↗

PubMed1992

High-fidelity gene targeting in embryonic stem cells by using sequence replacement vectors.

Mutations were targeted to the Hprt locus in murine embryonic stem cells by using sequence replacement vectors. When the vector was designed such that the mutated sequences were flanked on both sides by several kilobases of DNA homologous to the target locus, replacement of chromosomal sequences with the exogenous DNA occurred with precision. If, on the other hand, the target-homologous DNA on one arm of the vector was reduced to below 1 kb in length, the fidelity of recombination was diminished.

Animals↗

PubMed1992

Reexamination of gene targeting frequency as a function of the extent of homology between the targeting vector and the target locus.

Mutations were targeted to the Hprt locus of mouse embryo-derived stem cells by using 22 different sequence replacement and sequence insertion vectors. The targeting frequency was examined at two sites within the Hprt locus as a function of the extent of homology between the targeting vector and the target locus. The targeting frequency was also compared by using vectors prepared from isogenic and nonisogenic DNA sources. With one exception, all of the vectors showed the same exponential dependence of targeting efficiency on the extent of homology between the targeting vector and the target locus. This was true regardless of whether they were sequence replacement or sequence insertion vectors, whether they were directed toward either of the two different sites within the Hprt locus, or whether they were prepared from isogenic or nonisogenic DNA sources. Vectors prepared from isogenic DNA targeted four to five times more efficiently than did the corresponding vectors prepared from nonisogenic DNA. The single case of unexpectedly low targeting efficiency involved one of the vectors prepared from nonisogenic DNA and could be attributed to an unfavorable distribution of heterology between the Hprt sequences present in the targeting vector and the endogenous Hprt gene.

Animals↗

PubMed1992

[Alpha 2 megaloglobulin inhibits the activation of rabbit platelet by Chinese Agkistrodon acutus venom].

An in vitro study of alpha 2-mengaloglobulin (alpha 2MG) in the inhibition of the activation of washed rabbit platelet by Chinese Agkistrodon acutus venom (CAAV) was reported. Results showed that CAAV induced aggregation rate of washed rabbit platelet was positively related to the CAAV concentration, and the maximal aggregation rate was 43.8 +/- 9.9% at the concentration of 100 micrograms/ml. Meanwhile the release of serotonin (5-HT) and platelet factor 4(PF4) from the platelet reached maximum at the CAAV concentrations of 0.81 +/- 0.07 microgram/ml and 39.08 +/- 2.78%, respectively. Platelet aggregation and the release of 5-HT and PF4 induced by CAAV could be inhibited by the addition of 0.25% alpha 2 MG into the platelets both 1 minute before and 1 minute after the addition of CAAV. When alpha 2 MG was added to the platelets 1 minute prior to the addition of CAAV, the platelet aggregation and the ultrastructural changes which could be induced by CAAV were not observed, and the morphology of the rabbit platelets was the same as that of the normal counterparts.

Animals↗

PubMed1992

[Plasma fibronectin determination in acute bacterial pneumonia].

Plasma fibronectin (PFn) level was measured with immunoelectrophoresis in 40 healthy adults and 30 patients with acute bacterial pneumonia. The results showed that PFn was considerably lowered in acute bacterial pneumonia (214.49 +/- 77.84 micrograms/ml) when compared with that of healthy controls (292.48 +/- 43.11 micrograms/ml), (P less than 0.001). In the pneumonia group (10 severe cases) the level of PFn was significantly lowered than that in the moderate or mild cases (127.45 +/- 31.03 micrograms/ml vs. 255.11 +/- 54.16 micrograms/ml), (P less than 0.001). In 11 cases of recovering pneumonia, PFn was significantly higher than that in exacerbation period (213.13 +/- 41.32 micrograms/ml vs. 154.52 +/- 51.27 micrograms/ml) (P less than 0.001). We think that PFn level is helpful to evaluate the clinical course and prognosis of acute bacterial pneumonia.

Adolescent↗

PubMed1991

Anterior lentiplane and posterior lenticonus in two cases.

Posterior lenticonus has been reported by ophthalmologists, but anterior lentiplane never. Anterior lentiplane, whose characteristic is the flat or plane anterior capsule, has been discovered only recently. It is a special kind of congenital lens anomaly which may be in association with hyperplasia of the lens.

Adolescent↗

PubMed1991

[The influence of Chinese Agkistrodon acutus enzyme (CAAE) on the functions of washed human platelets].

The effects of the activation and influence of CAAE on washed human platelets were investigated. Our findings were: (1) CAAE could induce aggregation and alpha-granule release reaction in the washed human platelet suspension; thus it could activate the platelets; (2) the aggregation effect of CAAE was inhibited by albumin and affected by Ca2+, Mg2+ concentration; (3) heparin and/or AT III did not inhibit the aggregation activation of CAAE, but alpha 2MG markedly inhibited it; (4) the aggregation activity of CAAE was associated with the serine protease activity. The mechanism of CAAE-induced aggregation mainly follows the prostaglandins-endoperoxides thromboxane A2 pathway.

Animals↗

PubMed1989

[Projection of afferent impulses from the brachial plexus and sciatic nerve to the corpus striatum in pigeons].

The corpus striatum were systematically explored by recording averaged potentials elicited by stimulation of the brachial plexus and sciatic nerve in 53 pigeons. It was found that the projection areas of brachial afferents were located within the neostriatum, the hyperstriatum and the ectostriatum. The sciatic projection areas overlap with the brachial projection areas in the neostriatum and a part of the hyperstriatum. Moreover, the brachial and sciatic projection are as in the striatum receive the inputs from both sides of the body. We suggest that the somatic projection areas of fore- and hindlimb are distributed diffusely in the striatum of the pigeon. That the projection area of forelimb is relatively larger is probably related with functional differentiation of the forelimb. Furthermore, the convergence of afferent impulses originating in the different regions of the body within the same brain area may be important for the integration of limb activities in pigeon.

Afferent Pathways↗

PubMed1982

Monoclonal antibody specific for human T acute lymphoblastic leukaemia.

A cytotoxic mouse monoclonal antibody (CALL2) was produced against a cultured T acute lymphocytic leukaemia (T ALL) cell line 8402. Ascites fluid containing the antibody was cytotoxic to a titre of up to 1:100 000 against 4 of 6 cultured T ALL cell lines and against leukaemia cells from 7 of 8 T ALL patients and 1 of 5 T chronic lymphatic leukaemia patients. The antibody did not react with normal peripheral-blood T and B lymphocytes, monocytes, granulocytes, spleen cells, thymocytes, platelets, and other acute and chronic leukaemia cells. The CALL2 antibody did not react with bone marrow stem cells of the myeloid series (CFU-C). This antibody may be useful for passive immunotherapy trials since it does not react with normal cells and is highly cytotoxic to T ALL cells.

Antibodies, Monoclonal↗

PubMed1981

Cytotoxic monoclonal antibody to a human leiomyosacoma.

A monoclonal antibody produced by the hybridoma technique against a human leiomyosarcoma was highly cytotoxic in dilutions of 1:64 000 to the original tumour cells. The antibody was unreactive with most normal cells (lymphocytes, 120 donors; spleen cells, 73/75; monocytes, 16; granulocytes, 25; platelets, 12; red cells, 11) and could not be absorbed out by smooth muscle from the small intestine or by spleen cells. Its specificity for the tumour was high since it did not react with cells from 40 patients with leukaemia, from 8 patients with other tumours, and from 7 cultured tumour lines. The only other cell that it reacted with (at 1:4000 dilution) was line 8402, a T acute lymphocytic leukaemia line. This monoclonal antibody may be suitable for therapeutic trials.

Antibodies, Neoplasm↗

PubMedDate not supplied

Functions of mammalian Smad genes as revealed by targeted gene disruption in mice.

The Smad genes are the intracellular mediators of TGF-beta signals. Targeted mutagenesis in mice has yielded valuable new insights into the functions of this important gene family. These experiments have shown that Smad2 and Smad4 are needed for gastrulation, Smad5 for angiogenesis, and Smad3 for establishment of the mucosal immune response and proper development of the skeleton. In addition, these experiments have shown us the importance of gene dosage in this family, as several of its members yielded haploinsufficiency phenotypes. These include gastrulation and craniofacial defects for Smad2, accelerated wound healing for Smad3, and the incidence of gastric cancer for Smad4. Combinatorial genetics has also revealed functions of Smads in left/right isomerism and liver development.

Animals↗

PubMedDate not supplied

Role of the ras-MAPK signaling pathway in the DNA methyltransferase response to DNA hypomethylation.

Our group reported that inhibiting DNA methylation in human T cells increases DNA methyltransferase expression and activity, and suggested that this may represent a response to DNA hypomethylation. The increase correlates with increases in Ha-ras and c-jun, suggesting that increased signaling through the ras-MAPK pathway, due to overexpression of some elements, may be responsible. However, whether human DNA MTase is regulated by the ras-MAPK pathway, and whether overexpression of elements in this pathway will increase DNA MTase, is unknown. We report that treating cells with a DNA methylation inhibitor increases transcription regulated by a putative DNA MTase promoter, and that this increase requires AP-1 sites. Additional studies demonstrate that overexpression of an unmutated Ha-ras causes an increase in DNA MTase, and that human T cell DNA MTase can be decreased by inhibiting signaling through the ras-MAPK pathway. Together, these studies suggest that human T cell DNA MTase is regulated through the ras-MAPK pathway, and that overexpression of Ha-ras is sufficient to increase DNA MTase expression. These results thus provide a mechanism for the increase in DNA MTase observed after inducing DNA hypomethylation, a response which may have relevance to some disease states.

Animals↗