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Biomedical subjects

Y E Wang

Publications and source records attributed to Y E Wang.

At least 19 recordsLinked to original sources
PubMed1998

Drosophila nerve cord culture: a tool for studying neural development.

The culture of explanted neural tissues has been a useful tool for the study of cellular and molecular neurobiology in vertebrates. We have developed a technique for the culture of explanted ventral nerve cords from Drosophila embryos. We have examined the morphology and dynamic behaviour of the growth cones that extend from these nerve cords, and the effect of calcium deprivation on the bundling of axons that are regenerated from the explanted tissue. This technique offers a unique opportunity to combine in vitro techniques for neuronal cell culture with the powerful techniques of genetic analysis that are available with Drosophila.

Animals↗
PubMed1998

Arginine kinase expression and localization in growth cone migration.

Migrating neuronal growth cones exert traction forces that are generated by ATP-driven F-actin/myosin interactions. Sustained generation of these forces may require an energy supply mediated by the guanidino kinases, creatine kinase and arginine kinase. We cloned and sequenced grasshopper arginine kinase and examined its expression during embryogenesis and its subcellular localization in vivo and in vitro. During the first half of embryogenesis, arginine kinase is expressed selectively in a small percentage of ectodermal cells (dorsal closure cells), in a small percentage of mesodermal cells (muscle pioneers), and throughout the developing CNS. Most of these cell types are motile, including nascent neurons, muscle pioneers, dorsal closure cells, and many CNS glia. Neuroblasts also strongly express arginine kinase; they are nonmotile but are undergoing repeated rounds of (ATP-dependent) mitosis. Arginine kinase is colocalized with F-actin in a narrow band along the leading edges of lamellipodia of migrating glia. In neurons undergoing axonogenesis, arginine kinase is concentrated in growth cones and extends to the tips of filopodia. The amount of arginine kinase varies widely between growth cones, even between different growth cones of the same neuron. Energy for growth cone migration appears to be mobilized by (1) selective expression of arginine kinase by neurons, (2) localization of arginine kinase within growth cones, and (3) concentration of arginine kinase within specific growth cones, depending on the traction forces being generated. Mobilization of guanidino kinases may participate in the selective growth of specific growth cones.

Animals↗
PubMed1996

Effects of thiofedrine on platelet aggregation, thromboxane B2 and 6-keto-PGF1 alpha in rats.

Thiofedrine inhibited rat platelet aggregation and intraplatelet thromboxane B2 (TxB2) generation induced by arachidonic acid. The IC50 values were 0.18 and 0.21 mmol/l, respectively. Thiofedrine, 1.25-5.00 mg/kg i.v., showed a significant inhibition of rat platelet aggregation and intraplatelet TxB2 generation induced by arachidonic acid, with ID50 values of 2.4 and 3.3 mg/kg. Thiofedrine, 0.5-2.0 mg/kg i.v., reduced TxB2 generation but increased 6-keto-PGF1 alpha formation in rat plasma.

6-Ketoprostaglandin F1 alpha↗
PubMed1992

Subdomains of the octopine synthase upstream activating element direct cell-specific expression in transgenic tobacco plants.

Previous work has shown that the octopine synthase (ocs) gene encoded by the Agrobacterium tumefaciens Ti-plasmid contains an upstream activating sequence necessary for its expression in plant cells. This sequence is composed of an essential 16-bp palindrome and flanking sequences that modulate the level of expression of the ocs promoter in transgenic tobacco calli. In this study, we have used RNA gel blot analysis of RNA extracted from transgenic tobacco plants to show that the octopine synthase gene is not constitutively expressed in all plant tissues and organs. This tissue-specific pattern of expression is determined, to a large extent, by the 16-bp palindrome. Histochemical analysis, using an ocs-lacZ fusion gene, has indicated that the 16-bp palindrome directs the expression of the ocs promoter in specific cell types in the leaves, stems, and roots of transgenic tobacco plants. This expression is especially strong in the vascular tissue of the leaves, leaf mesophyll cells, leaf and stem guard cells, and the meristematic regions of the shoots and roots. Sequences surrounding the palindrome in the upstream activating sequence restrict the expression of the ocs promoter to fewer cell types, resulting in a reduced level of expression of beta-galactosidase activity in the central vascular tissue of leaves, certain types of leaf trichomes, and the leaf primordia.

Amino Acid Oxidoreductases↗
PubMed1991

[Antifertility effect of the implant containing 16-methylene-17 alpha-acetoxy-19-norprogesterone (ST-1435)].

The silastic capsules containing ST-1435 (0.5, 1, 2, 4, 6 or 8 mg) showed "burst effect" with a peak value of 4-15 micrograms.h-1 after incubation in vitro. A constant release rate was gradually approached within 1-2 wk. After the capsules were subcutaneous implanted or vaginally administrated, the rats manifested diestrus within 24-48 h. The normal estrus cycles and fertility were restored as soon as the release rate of implants decreased to 10 micrograms.d-1 in vitro. ST-1435 did not inhibit the superovulation induced by PMSG and HCG in immature female rats, but blocked the ovulation induced by LHRH in mature rats.

Animals↗
PubMed1991

Renal metastases of choriocarcinoma. A clinicopathological study of 31 cases.

From 1949 through 1978, 31 patients with renal metastasis were diagnosed in a total of 448 cases of choriocarcinoma admitted to our hospital, giving an incidence of 6.9%. Renal metastasis was invariably preceded by pulmonary metastases and usually accompanied by other visceral metastases, indicating that renal metastasis is the result of dissemination of tumor cells secondarily from lung metastasis through the general circulation and should be categorized as arterial metastasis. Pyelogram is useful in the presence of medullary invasion by the tumor. Renal metastatic tumors are very sensitive to chemotherapy. Good response to chemical agents may be due to high drug concentration attained in the kidney tissue during excretion. Since successful treatment of renal metastasis by chemotherapy alone may be obtained, patients can be spared a major operation without jeopardizing the prognosis.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Clinical significance of hysterography in the diagnosis of choriocarcinoma and invasive mole.

From 1963 through 1988, a total of 194 hysterographies were performed for 111 patients. Three types of abnormalities were observed on the hysterogram: filling defect, intramural invasion of the uterine wall by the contrast medium; and intravasation of the contrast medium into the pelvic veins. The pathology and clinical significance of three types of abnormalities were studied. The results showed that hysterography demonstrated better images than pelvic arteriography and B-scan for the diagnosis of choriocarcinoma and invasive mole, especially when combined with B-scan/or pelvic arteriography, a greater accuracy was achieved.

Choriocarcinoma↗
PubMed1990

[Atypical choriocarcinoma. Analysis of 3 cases].

Atypical choriocarcinoma is a rare type of gestational trophoblastic disease and only 3 cases were diagnosed among a total of 696 patients with choriocarcinoma admitted to our hospital from 1949 through 1985. Atypical choriocarcinomas different from the regular choriocarcinoma in both histopathology and clinical manifestations. Morphologically, the tumor cells are predominantly cytotrophoblasts and clinically, the hCG titer is very low which is undetectable by routine biological or immunologic assays. Therefore, it is not infrequently misdiagnosed as sarcoma, squamous cell carcinoma or clear cell carcinoma of the uterus. A comprehensive review of the past history and clinical manifestations is most essential to obtain a correct diagnosis.

Adult↗
PubMed1988

Pregnancy outcomes after successful chemotherapy for choriocarcinoma and invasive mole: long-term follow-up.

In order to preserve the fertility of young patients with choriocarcinoma and invasive mole, chemotherapy alone was given without hysterectomy in 265 cases from 1959 through 1980. By the end of 1985, 205 patients had become pregnant after recovery, with a total of 355 pregnancies. Among these, 23 were terminated by induced abortions, 26 as miscarriages, two as ectopic gestations, two as intrauterine deaths, and three as stillbirths. Among 303 livebirths (including four sets of twins), six infants died neonatally, three of whom were found to have congenital anomalies incompatible with life, and two died during infancy. All the remaining 295 children had normal growth and development, the oldest now being 25 years of age. The rates of fetal wastage, malformations, twin pregnancies, and neonatal and infantile deaths did not deviate from the normal. Cytogenetic study of the peripheral lymphocytes of 94 of the children revealed no increase of chromosomal aberrations. The rates of recurrence of disease and of death caused by recurrence of disease in these were not increased in comparison with those in patients who underwent hysterectomy. These data indicate that treatment of malignant trophoblastic neoplasms with chemotherapy alone is compatible with the preservation of fertility in most women.

Adult↗
PubMed1985

Resection of pulmonary metastatic choriocarcinoma in 43 drug-resistant patients.

A regimen of multiple intermittent intensive doses of chemotherapy (chiefly 5-fluorouracil) was used in a series of 806 women with choriocarcinoma and malignant mole. The rate of complete remission of choriocarcinoma was 78.6%, and approximately 85% of the patients survived for more than 5 years. From 1962 through 1982, pulmonary metastatic choriocarcinoma was found to be resistant to chemotherapeutic agents in 43 of these patients; they subsequently underwent lung resection. There were no postoperative deaths, and the 5-year survival was 50%. These are relatively good results for patients with long-standing and widely disseminated choriocarcinoma. Human chorionic gonadotropin titer in urine and blood and variations of lung shadows are important criteria in selecting candidates for lung resection. For preservation of lung function, simple lobectomy is the first choice. Better long-term survival was obtained in patients who had a solitary lung lesion on admission without other major organ metastases and in those in whom the lung lesion was well encapsulated and became necrotic after chemotherapy.

Adult↗