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Biomedical subjects

W X Ma

Publications and source records attributed to W X Ma.

14 recordsLinked to original sources
PubMed2001

neurogenin2 elicits the genesis of retinal neurons from cultures of nonneural cells.

neurogenin2 (ngn2) encodes a basic helix-loop-helix transcription factor and plays an important role in neurogenesis from migratory neural crest cells. Its role in retinal development is poorly understood. We observed that in the developing chick retina, ngn2 was expressed in a subpopulation of proliferating progenitor cells. Ectopic expression of ngn2 in nonneural, retinal pigment epithelial cell culture triggered de novo generation of cells that expressed neural-specific markers and exhibited neuronal morphologies. Further molecular and morphological analyses showed that the main products of the induced neurogenesis were cells resembling young photoreceptor cells and cells resembling retinal ganglion cells. The generation of multiple cell types suggests that ngn2 induces various retinal pathways. Thus, unlike in the peripheral nervous system where ngn2 specifies one type of sensory neuron, ngn2 in the retina is likely involved in a common step leading to different cellular pathways. Our finding that ngn2 can instruct nonneural retinal pigment epithelial cells to differentiate toward retinal neurons demonstrates one possible way to induce de novo retinal neurogenesis.

Animals↗
PubMed2001

[Determination of micro-elements in natural spirulina using FAAS].

The analytic results show that the spirulina powder have a plenty of microelements(K, Na, Ca, Mg, Fe, Zn). Compared with that of rice, wheat flour, maize and soybean, the content of K, Na, Ca, Mg, Fe and Zn of it is respectively as from 4 to 10 times, from 10 to 80 times, from 25 to 70 times, from 3 to 15 times, from 4 to 36 times and from 4 to 24 times as theirs. The content of microelements of it compared with vegetable is much higher. The spirulina has a certain inhibition from cancer, high blood pressure, sugar diabetes and hasten body to absorb Se and Mo, and is of benefit to cardiac muscle. The experimental result indicated that spirulina was good health care food with value of nourish and medicinal.

Bacterial Proteins↗
PubMed1997

Can superoxide dismutase prevent postburn dermal ischemia?

Decreasing progressive dermal ischemia after burning could theoretically limit the amount of skin necrosis. It is controversial whether the use of free radical scavengers could prevent the progressive dermal ischemia of the postburn stasis zone. We evaluated the effect of superoxide dismutase (SOD) on preventing postburn dermal ischemia in animal models by the India ink perfusion and skin transparent preparation techniques. The closely clipped backs of guinea-pigs were bathed in 75 degrees C water for 10 s. Within 5 min postburn, SOD-treated groups were administered SOD (10,000 u/kg) intra-peritoneally every 6 h. All animals were perfused with 70 per cent India ink via cervical artery cannula by 16 kPa constant pressure at 0, 8, 16, 24 h postburn, and the skin transparent preparations were made, while the level of malonyl dialdehyde (MDA) in skin tissue was assessed. The results showed that with prolongation of postburn time, the rate of filling of India ink in skin capillary plexuses decreased gradually (p < 0.01). MDA increased continuously, which was related to postburn dermal ischemia (r = 0.689, p < 0.01). Though the level of MDA decreased in SOD-treated groups, the India ink filling rates showed no significant difference between controls and experimental groups (p > 0.05). The results were also confirmed by observation of skin transparent preparations and TEM. This study suggests that superoxide dismutase fails to prevent progressive dermal ischemia after burning.

Animals↗
PubMed1989

[Immunohistochemical detection of prostate carcinoma].

Both prostate specific acid phosphatase (PAP) and prostate specific anti-body (PSA) were used as the specific markers for detecting prostate cancer and its metastasis, and this was considered as the most efficient technique for detecting metastatic lesions associated with an occult carcinoma in the prostate. Altogether 44 cases were studied, including 23 cases of prostatic carcinoma, 3 cases of metastatic tumors and 18 cases of benign hypertrophy of prostate (including 4 cases with local carcinoma). Analysis of 27 cases revealed that PSA seemed more sensitive than PAP, as 17 cases of prostatic carcinoma showed positive reaction with PSA, while among them, only 3 showed negative reaction with PAP. Most of the well differentiated glandular type prostatic carcinoma showed strong positive reaction. However, the poorly differentiated solid carcinoma only showed mild positive reaction. All of the controls as well as bladder and kidney cancers showed negative reaction with either PAP or PSA.

Acid Phosphatase↗
PubMed1989

[Cytologic diagnosis of prostatic carcinoma by transrectal prostatic aspiration biopsy].

Since October 1982, 500 cases of transrectal fine needle aspiration biopsy have been done. Among them, 486 cases (97.2%) got prostate epithelium enough for diagnosis but 14 cases (2.8%) failed. The cytologic results showed prostatic cancer in 100 cases (20.5%), bladder cancer with metastasis to prostate in 7 cases (1.4%), suspicious cancer in 4 cases (0.82%), hyperplasia of prostate 251 cases (51.64%), normal prostate 104 cases (21.3%), tuberculosis one case (0.2%), lithiasis one case (0.2%), purulent prostatitis 4 cases (0.82%), granulomatous prostatitis 6 cases (1.23%), and insufficient epithelium for diagnosis in 8 cases (1.64%). In this series, there were one false positive and two false negative by Franzen's technique. Among 41 cases received further treatment, 35 prostate specimen were available for regular pathological study. The consistent rate between pathological and cytologic diagnosis was 85.4%. In a word, transrectal prostatic aspiration is an outstanding safe and practical method for the diagnosis of prostate cancer.

Adult↗
PubMed1988

[Prostatic carcinoid and neuroendocrine tumors--a case report].

This paper reports a rare primary prostatic adenocarcinoid tumor confirmed by electron microscopy as well as immunohistochemical method including prostate specific antigen and prostatic acid phosphatase. Electron microscopy showed the presence of neuroendocrine granules in the cytoplasm of some tumor cells and the latter method ruled out the possibility of secondary tumor from other organs. It is noted that prostatic adenocarcinoid tumor is one of the diffuse neuroendocrine system tumors. Although the histogenesis of these tumors is not entirely clear, it is believed to be of multiple origins, and may transform through metaplasia into neoplasm.

Carcinoid Tumor↗
PubMed1987

[Establishment of human glioma cell line--nude mice solid tumor model NHG-1 and its characteristics].

Establishment and its characteristics of a nude mice solid tumor model NHG-1 from human glioma cell line are reported. 5-8 week old NC nude mice of both sexes and SHG-44 cell line used in this experiment were from our laboratory. The initial successful transplantation rate was 7/11 (64%) and that of 30 passages in the subsequent 4 years was 100%. After subcutaneous inoculation, growth curve showed a latent period in week 1-2, slow growing period in week 3-4, rapid growing period in week 5-6 and a final plateau period in week 7. The doubling time was 7 days and cell cycle time was 2.5 days. The cells in G1, S and G2M phases comprised 56%, 27% and 17%, respectively. The survival time of the host was 54 +/- 15 days. The tumor tissues showed a tendency towards invading the surrounding soft tissues. By morphological observation with light and electron microscopes, LDH isozyme assay, PAP immuno-histochemistry labelling GFAP and chromosome analysis, it is confirmed that the transplantable tumor possesses the characteristics of human malignant glioma. The estrogen receptor in the transplantable tumors demonstrated by cytochemical assay indicates that the glioma carcinogenesis is related to endocrine factor of the host. The therapeutic effects of anticancer drugs, such as ACNU, BCNU and 10-hydroxy-2-decenoic acid from the royal jelly on NHG-1 model are evaluated.

Animals↗