Biomedical subjects

M Y Tang

Publications and source records attributed to M Y Tang.

At least 19 recordsLinked to original sources

PubMed2006

Delayed spinocerebellar ataxia in transgenic mice expressing mutant ubiquitin.

Spinocerebellar ataxia type 1 (SCA1) is an incurable neurodegenerative disease resulting from loss of Purkinje neurones within the cerebellum. The ubiquitin proteasome pathway (UPP) has been implicated in SCA1 but the role of proteolysis in the disease is still poorly understood. To further investigate this issue in vivo, genetic crosses were performed between an established mouse model of SCA1 and novel strains expressing elevated levels of wild type or mutant isoforms of ubiquitin. The K48R mutant isoform of ubiquitin (a dominant negative inhibitor of proteolysis) was found to significantly delay the deterioration of Purkinje neurones as evidenced by behavioural, morphological, and molecular indicators. This delay was accompanied by stabilization of p300/CBP, transcriptional mediators whose abundance and activity would otherwise decline in the course of the SCA1 disease, and persistence of protein kinase C gamma (PKCgamma), a protein involved in Purkinje cell dendritic development that is mutated in one form of spinocerebellar ataxia. Whereas the stabilization of p300/CBP was found to occur at the post-translational level the modulation of PKCgamma was at the level of transcription. These results are consistent with transcriptional dysregulation as a key mechanism in neurodegeneration through loss of p300/CBP. Further, the results suggest that the UPP is a potentially useful target for the development of novel therapies for the treatment of neurodegenerative disease.

Animals↗

PubMed1994

Incidence of Listeria spp. in vegetables in Kuala Lumpur.

From April 1992 to September 1992, 280 samples of 10 different fresh vegetables, bought from four different market outlets in Kuala Lumpur were examined for the presence of Listeria spp. Most of the market produce were locally grown with the exception of carrots. The isolation procedure was based on the Food & Drug Administration method (modified) used for the detection of Listeria spp. Isolation media used were Listeria Selective medium and LiCl- phenylethanol-Moxalactam agars. The identification of isolates was by means of conventional biochemical tests and API Listeria identification system. Five out of the 280 samples showed Listeria contamination, Listeria monocytogenes was isolated in lettuce, sengkuang (Pachyrrhizus erosus) and selom Oenanthe javanica) and Listeria innocua was isolated from sengkuang (Pachyrrhizus erosus) and pegaga (Hydrocotyle asiatica).

Food Handling↗

PubMed1991

Treatment of malignant ovarian germ cell tumors with preservation of fertility: a report of 28 cases.

Preservation of fertility was carried out in 28 young patients with malignant germ cell tumors of the ovary from 1962 through 1987. The pathologic diagnosis was immature teratoma in 16, endodermal sinus tumor in 7, dysgerminoma in 2, and germ cell tumor of mixed type in 3. At laparotomy, 16 patients were proved to have stage I disease, 1 had stage II disease, 9 had stage III disease, and 2 had stage IV disease. The tumor was confined to one ovary in all 22 cases treated for the first time, and the preserved ovary and uterus were normal in all 6 referred cases with recurrent diseases. Postoperative chemotherapy was given to all patients except two with stage I immature teratoma. Persistent remission was achieved in 22 patients; 5 patients died and 1 was lost to follow-up. The duration of follow-up was more than 1 year for all surviving patients, more than 3 years in 16 cases (72.7%), and more than 5 years in 13 cases (59.1%). The menstrual periods were normal in all except 3 cases, of whom 2 were below the age of 12 and one failed to menstruate at the age of 21 with a hypoplastic uterus and underdeveloped secondary sex characters. Among 12 married patients, 7 of 10 desirous of child-birth became pregnant during follow-up. Of these, 6 had a normal term delivery and 1 is currently pregnant. The preliminary conclusion is that preservation of fertility for young patients with malignant germ cell tumors of the ovary, regardless of the stage of the disease, is a safe and practicable procedure in the absence of involvement of the contralateral ovary and uterus.

Adolescent↗

PubMed1991

[Immunoregulatory role of thyroid hormone].

The immunoregulatory role of thyroid hormone was investigated in mice weighing 20-30 g. The experimental results showed that the antibody production, transformation of lymphocytes, DTH response (delayed-type hypersensitivity response) and phagocytosis of the peritoneal macrophages were all markedly enhanced when the animals were fed with a daily dose of 2 mg thyroid hormone for 14-18 days. The number of mature T cells in peripheral blood was also increased significantly by the thyroid hormone. When mice were administered with antithyroid drug (methylthiouracil), the antibody production, the transformation of lymphocytes and DTH response were inhibited. Thyroidectomy could also suppress the antibody production. The results suggest that thyroid hormone is involved in the regulation of immune function.

Animals↗

PubMed1990

Pathologic analysis of preterm delivery placentas.

198 preterm delivery placentas of 28 weeks to less than 37 weeks pregnancy were analyzed. Gross examination revealed that the differences of placenta previa and low implantation (2.91%), bipartate placenta and rupture of marginal sinus (0.97% respectively), large placenta (2.91%), short cord (4.85%), velamentous insertion of cord (3.88%), etc in comparison with those of term delivery placentas were statistically significant. Microscopic examination of 165 placentas showed that in 19 cases (11.52%) of infection of membranes and umbilical vessels, 11 were due to premature rupture of membranes or cervical interventions and 8 to preterm delivery. Among 72 cases of PIH, 65 (90.28%) had arteriopathy of decidua capsularis. 18 cases (25%) which had not been diagnosed clinically as PIH were found to be neglected after discovery of arteriopathy of decidua capsularis by pathologic examination. Placental examinations showed that preterm delivery may be attributable to the factors of placenta, amniotic fluid and umbilicus. 20 cases (27.78% of total PIH) of premature rupture of membranes were complicated by PIH. Whether the cases of decidual arteropathy are liable to have rupture of membranes awaits further investigation.

Female↗

PubMed1990

[Malignant Brenner tumor and transitional cell carcinoma of the ovary].

The clinical and pathologic features of 2 malignant Brenner tumors (MBT) were compared with those of 13 primary ovarian transitional cell carcinomas (TCC). Though histologically both tumors were invasive transitional cell carcinoma, TCC differed from MBT by the absence of benign Brenner component and stronger aggressiveness in behavior. Among tumors of both types in similar clinical stage, most of TCC (6/9) died within 1 to 2 years after the operation, but one of MBT died 4 years postoperatively. The distinction between MBT and TCC bearing on therapeutic as well as prognostic implications is discussed.

Adult↗

PubMed1989

Intestinal metastasis and operation in ovarian cancer: a report on 62 cases.

Among numerous sites of metastasis in ovarian cancer, the most common and serious one is the intestinal tract. However, reports on ovarian malignancy with special reference to intestinal metastasis and its surgical treatment have been few. This paper is a retrospective analysis of cases of ovarian cancer with intestinal metastasis treated at the Peking Union Medical College Hospital. Sixty-two cases of ovarian cancer with intestinal metastatic tumours larger than 2 cm in diameter were treated between January 1982 and October 1987, accounting for 28.2% of a total of 221 cases of ovarian cancer admitted during the same period. Twenty-seven patients were operated on for the first time, 24 were referred from other hospitals where the cancer was considered 'inoperable' during the initial surgery, and 11 were recurrent cases. Of the 62 cases, 51 had epithelial cancer and 11 had germ-cell tumours. Metastasis to the large intestine was observed in all 62 cases, of which the rectosigmoid was involved in 59 (95.2%). Metastasis to the small bowel was observed in 26 cases (41.9%). Superficial or serosal invasion occurred in 40 cases (64.5%), and deep invasion, in which the muscularis or both muscularis and mucosa were involved, occurred in 22 cases. A complete or optimal resection of the intraperitoneal tumours was achieved in 46 cases (74.2%). Resection of metastatic tumours of the intestine was performed in 40 cases, of which a repair of the perforated intestinal wall was required in 19. Resection of the bowel was carried out in 22 cases, and a colostomy was done in 6. Postoperatively, all patients were followed up for at least 6 months. During follow-up, 17 patients (27.4%) survived, 39 died and 6 had recurrent disease. The mean survival time for 17 patients achieving complete remission was 30.3 months. Of these, ten have survived for more than 2 years, and seven for more than 3 years. The survival rate was higher in patients with germ-cell tumours and in those having superficial invasion of the intestinal wall, optimal cytoreduction of tumour and relatively sufficient postoperative chemotherapy. However, only the latter two prognostic factors were found to bear statistical significance. The role and feasibility of bowel surgery in ovarian cancer are discussed.

Adolescent↗

PubMed1989

Lymph node metastasis and retroperitoneal lymphadenectomy in ovarian cancer.

While clinicians are devoting themselves to the study of the behaviour of ovarian cancer as well as to the search for more effective therapeutic modalities, little attention has been paid to an important route of metastasis in this group of diseases: retroperitoneal spread through the lymphatic pathway. The purpose of this report is to present a 5-year experience of a prospective study on lymph node metastasis in patients with ovarian cancer through retroperitoneal lymphadenectomy at the Peking Union Medical College Hospital. From June 1982 through May 1987, retroperitoneal lymph node dissection was performed in 105 cases of ovarian cancer. Seventy-seven (73.3%) were histologically diagnosed as cancer of epithelial origin, and 28 (26.7%) as germ-cell tumours. The overall incidence of retroperitoneal positive nodes was 54.3% (57/105). The incidence of positive pelvic nodes was 46.7% (49/105), and that of positive para-aortic nodes was 37.5% (30/80). In 69 patients who underwent systemic lymphadenectomy, 39 were found to have glandular involvement; in these 39 patients both aortic and pelvic nodes were positive in 19 cases (48.7%), aortic nodes were positive and pelvic nodes negative in 7 cases (18.0%), and pelvic nodes were positive and aortic nodes negative in 13 cases (33.3%). Preoperative lymphography was performed in 30 cases. The positive and negative correspondence rates with the pathological findings were both 83.3%. In 38 cases in which the primary cancer originated in the left ovary, 17 (44.7%) were found to have positive pelvic nodes, whereas in 25 cases with primary cancer arising in the right ovary only 2 (8%) had metastasis of the ipsilateral pelvic nodes. The lymph nodes obtained from 22 patients with positive nodes and sufficient preoperative chemotherapy were carefully examined under the microscope for the effects of the drugs. Some cellular degeneration of the lymph node metastasis was observed in only one of the 15 cases of epithelial cancer, and no response at all was noted in three cases of immature teratoma. Cellular degeneration accompanied by extensive necrosis was demonstrated in the metastatic tumours of the lymph nodes in all four cases of endodermal sinus tumour. Seventy-two patients were followed-up for at least 2 1/2 years. The rate of complete remission was 46.7% (14/30) in patients with negative nodes, but only 33.3% (14/42) in those with positive nodes. However, the difference was not statistically significant.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1989

Clinicopathological analysis of causes of perinatal death.

The perinatal mortality rates and causes of deaths in our hospital within the three 5-year periods (1955-1959, 1976-1980, 1981-1985) were reported as well as the total number of births (16,846), deaths (457), and autopsies (393, autopsy rate 85.9%). The perinatal mortality for the three 5-year periods was 44.5%, 23.8%, and 17.2% respectively; it declined more significantly in 1981-1985 than in 1976-1980. Anoxia was the first cause of death for the three 5-year periods. Other causes in sequence in 1955-1959 were traumatic intracranial hemorrhage and pulmonary diseases, in 1976-1980 malformation and pulmonary diseases, and in 1981-1985 anoxia, pulmonary diseases and hyaline membrane disease. Results suggest that accurate analysis of causes of deaths depends on meticulous systematic fetal and neonatal autopsy, including macerated fetuses, extensive discussion by pathologists, obstetricians and neonatalogists, and indispensable placental examination.

Cause of Death↗

PubMed1989

[Pathologic analysis of the placenta in preterm deliveries].

The results of pathological analysis of 198 placentae from preterm deliveries of 28-37 week pregnancy in year 1985-1988 were presented Grossly there were: placenta previa and low implantation 2.91%, bipartate placenta and rupture of marginal sinus 0.97%, large placenta 2.91%, short cord 4.85%, velamentous insertion of cord 3.88, etc; all significantly different from those from term deliveries statistically. Microscopic, 165 placentae showed: infection of membranes and umbilical vessels in 19 (11.52%), of which 11 cases were with premature rupture of membranes or cervical interventions and 8 could be regarded as the cause of preterm delivery. Among 72 PIH cases, 65 (90.28%) had arteriopathy of decidual capsularis. Notably 18 cases (25%) of PIH were not diagnosed as such clinically until the discovery of arteriopathy of decidual capsularis microscopically and upon reviewing the case history. Combining with placental examinations, it is possible to tell the cause of preterm delivery whether in placenta, amniotic fluid or umbilical cord. In 20 PIH cases (27.78% of total PIH) with premature rupture of membranes, whether the decidual arteriopathy makes it liable to have membranes ruptured needs further study.

Decidua↗

PubMed1989

Luteal function in patients with endometriosis.

Nineteen patients with endometriosis were selected for investigation of luteal function as determined by serum progesterone (P) concentrations at different stages of the luteal phase, and by observation of basal body temperature (BBT) profiles and endometrial histological appearances. Sixteen cases were accompanied with infertility. All data were synchronized to the day of midcycle serum luteinizing hormone (LH) peak (D0) and analyzed accordingly. In the endometriosis group, mean serum P concentrations of early, mid luteal phases and the integrated P concentration of the whole luteal phase were significantly lower than in the control group. Five cases (26.3%) had low peak P values during mid-luteal phase and/or low integrated P levels. Delayed endometrial maturation was revealed in 10 of 16 cases (62.5%). Short luteal phase, as defined by BBT, was observed in 3 of 14 cases (21.4%). A total of 12 cases were screened for all three parameters, among them, ten (83.3%) had at least one abnormality and seven (58.3%) showed two aberrant results. In summary, the incidence of luteal phase defect was higher in the endometriosis group than in controls. The pathogenic mechanism of luteal phase defect and its role in infertility are discussed.

Adult↗

PubMed1988

End-to-end oesophageal anastomosis: an experimental study in the rat.

To study the effects of suture material, calibre and tension on the end-to-end oesophageal anastomosis, the cervical oesophagus of the rat was resected for 2.5 mm, 7.5 mm and 12.5 mm respectively in three groups of 60 rats each. End-to-end anastomosis was performed with either 6/0 silk, 6/0 polypropylene or 9/0 polypropylene sutures. There was no postoperative leakage. Mortality was mainly due to hair bolus obstruction at the site of anastomosis. There was no difference in mortality and anastomotic stenosis between groups with different resection lengths. Within each group, however, mortality and anastomotic stenosis were significantly higher in the subgroup of rats with 6/0 silk suture than that in the subgroup with 6/0 polypropylene sutures, which also had significantly higher mortality and anastomotic stenosis than the subgroup with 9/0 polypropylene sutures. Histological examination of the stenosed anastomosis showed disruption of muscle layers and submucosal thickening. It is concluded that the use of fine calibre sutures of biologically inert material would be preferred for the end-to-end anastomosis of the oesophagus.

Anastomosis, Surgical↗

PubMed1988