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Biomedical subjects

K C Wang

Publications and source records attributed to K C Wang.

At least 145 records · Page 8Linked to original sources
PubMed1980

Effector and enhancing lymphoid cells in plasmacytoma-bearing mice. I. Methodological studies on the Winn assay.

Some parameters of the Winn assay for the detection of tumor-suppressing ("effector") and tumor-enhancing lymphoid cells were studied in BALB/c mice. Spleen cells of mice that were preimmunized with mitomycin-C-treated MOPC-104E plasmacytoma cells were inhibitory in this test system for both the MOPC-104E and the HOPC-I plasmacytomas, thus indicating cross-reactivity. Spleen cells taken from mice 6 days after the surgical removal of 15-day-old MOPC-104E tumors inhibited the growth of lethal doses of MOPC-104E cells in normal recipients, but no inhibition was observed 2 days after the removal of 18-day-old tumors. Spleen cells from mice bearing MOPC-104E for 13 days enhanced tumor growth. This enhancement was not influenced significantly by the wide dose range (from 10(5) to 3 x 10(7)) of MOPC-104E cells used to initiate tumors in the lymphoid cell donors, although tendency for stronger enhancing potential occurred after low tumor doses. When spleen cells from donors bearing MOPC-104E for 10 days were injected at the constant tumor-lymphocyte ratio of 1:30 with increasing numbers of tumor cells (from 5 x 10(5) to 2 x 10(6)), tumor inhibition occurred at the lowest dose only, while no significant effect was observed at higher tumor cell doses. When a constant dose (5 x 10(5)) of tumor cells was injected with spleen cells from 10-day tumor-bearers at tumor/lymphocyte ratios of 1:10, u:40 and 1:160, a significant tumor inhibition occurred only at the ratio of 1:40. The relevance of the Winn test to the study of immune mechanisms in tumor-bearing hosts is discussed.

Animals↗
PubMedDate not supplied

Pineal tumors: experience with 48 cases over 10 years.

The authors retrospectively reviewed 48 patients treated at Seoul National University Hospital (SNUH) between 1986 and 1995. There were 35 children and 13 adults, accounting for 10.1% of 345 pediatric and 0.68% of 1914 adult brain tumors in SNUH during the same period. The 48 cases consisted of 33 cases of germ cell tumor (69%, GCT); 6 of pineoblastoma (PB, 12.5%); 3 of pineocytoma (PC, 6.3%); 3 of anaplastic astrocytoma (6.3%); 1 of astrocytoma; 1 of glioblastoma; and 1 of ependymoma. The median age was 13 years (range 1-59) and the male-to-female ratio was 3.36:1. The most frequent presenting symptom was due to increased intracranial pressure (90%), followed by Parinaud syndrome or diplopia (50%). Patients with a benign tumor, such as teratoma (TE), astrocytoma, or ependymoma, underwent surgery by the occipital transtentorial approach (OTT) for attempted radical resection without adjuvant therapy, while patients with immature teratoma (imTE), PC, and anaplastic astrocytoma underwent regional radiotherapy (RT) after debulking via OTT. Seven patients with nongerminomatous malignant GCT (NG-MGCT) and 3 with germinoma (GE) underwent craniospinal radiation only, 6 with GE, a NG-MGCT, and 2 with GE+TE received craniospinal radiotherapy (CSRT) after debulking via OTT. Three patients with GE, 4 with NG-MGCT, and 3 with PB underwent radiochemotherapy after debulking via OTT. Forty-four patients were followed up after treatment. The median follow-up period was 36 months. All patients with GE were alive after RT at 36 months (median) of follow-up (range 7-70 months). All with GE+TE and TE were alive. Three patients with PC or astrocytoma were also alive with stable or no evidence of disease. In 1 of the 3 cases of imTE there was a recurrence. However, 4 patients with NG-MGCT died, all of whom had undergone CSRT only; 2 PB patients were alive (12, 19 months), 1 in a moribund status (36 months), and 2 were dead (6, 60 months). The overall mean survival time with pineal tumors was 66 months and the 3-year survival rate was 84% with minimal posttreatment complications. It is concluded that pineal region tumors have male and childhood predominances, and the most common tumor is GCT. The majority of pineal region tumors are malignant. Pineal region tumors can be approached safely and effectively and the surgical complications are mostly transient. Their prognosis is dependent on the pathologies and treatment modalities.

Adolescent↗
PubMedDate not supplied

Extrapontine myelinolysis caused by electrolyte imbalance during the management of suprasellar germ cell tumors. Report of two cases.

Extrapontine myelinolysis (EPM) is caused by marked fluctuation of the serum electrolyte level. Patients with suprasellar germ cell tumors frequently present with diabetes insipidus, which is often aggravated by administration of steroid hormone. In addition, cisplatin-based chemotherapy is sometimes accompanied by marked serum electrolyte fluctuation because it needs massive hydration to prevent renal damage. Two children with suprasellar germ cell tumors in whom EPM developed secondary to profound hyponatremia and was rapidly corrected are described. The central pons was spared in both cases. Clinically the children showed transient neurological deficits including confusion, pseudobulbar palsy, and deterioration of consciousness. MRI demonstrated bilateral symmetrical, high-signal-intensity (HSI) lesions on T2-weighted images (T2WI) at the basal ganglia and adjacent cerebral cortex. Follow-up T1WI a few months later revealed newly developed HSI lesions in the basal ganglia. The patients gradually improved, but the neurological deficits did not completely disappear. During the perioperative management of suprasellar germ cell tumors, EPM should be considered when a patient has a significant electrolyte imbalance and neurological deficits, especially confusion and pseudobulbar palsy.

Child↗
PubMedDate not supplied

Pediatric pineal tumors: need for a direct surgical approach and complications of the occipital transtentorial approach.

In an investigation of the benefits and risks of direct surgical approaches to pediatric pineal tumors, the need for such approaches, the feasibility of surgical removal and operative complications were evaluated in 25 histologically proven cases. Five tumors were germinomas (GEs) or GE-predominant mixed germ cell tumors (GCTs), in which stereotactic biopsy can be adequate. Twenty of the 25 pineal tumors (80%) were teratomas (TEs), TE-predominant mixed GCTs or other tumors that need direct surgical approaches. Among the 21 tumors resected by the occipital transtentorial (OTT) approach, 13 were removed radically (>95%) and 6 others, subtotally (>75%). Complications of using the OTT approach included homonymous hemianopsia (7), Parinaud's syndrome (6), other eyeball movement limitation (7), seizure (5), and new hydrocephalus (3). The majority of these were transient, resolving within a few days or months, or easily controlled. The results showed that 80% of pediatric pineal tumors needed direct surgical approaches and that the majority were successfully removed by OTT surgery with an acceptable level of risk.

Adolescent↗
PubMedDate not supplied

The role of microglial cells and astrocytes in fibrillar plaque evolution in transgenic APP(SW) mice.

Ultrastructural reconstruction of 27 fibrillar plaques in different stages of formation and maturation was undertaken to characterize the development of fibrillar plaques in the brains of human APP(SW) transgenic mice (Tg2576). The study suggests that microglial cells are not engaged in Abeta removal and plaque degradation, but in contrast, are a driving force in plaque formation and development. Fibrillar Abeta deposition at the amyloid pole of microglial cells appears to initiate three types of neuropil response: degeneration of neurons, protective activation of astrocytes, and attraction and activation of microglial cells sustaining plaque growth. Enlargement of neuronal processes and synapses with accumulation of degenerated mitochondria, dense bodies, and Hirano-type bodies is the marker of toxic injury of neurons by fibrillar Abeta. Separation of amyloid cores from neurons and degradation of amyloid cores by cytoplasmic processes of hypertrophic astrocytes suggest the protective and defensive character of astrocytic response to fibrillar Abeta. The growth of cored plaque from a small plaque with one microglial cell with an amyloid star and a few dystrophic neurites to a large plaque formed by several dozen microglial cells seen in old mice is the effect of attraction and activation of microglial cells residing outside of the plaque perimeter. This mechanism of growth of plaques appears to be characteristic of cored plaques in transgenic mice. Other features in mouse microglial cells that are absent in human brain are clusters of vacuoles, probably of lysosomal origin. They evolve into circular cisternae and finally into large vacuoles filled with osmiophilic, amorphous material and bundles of fibrils that are poorly labeled with antibody to Abeta. Microglial cells appear to release large amounts of fibrillar Abeta and accumulate traces of fibrillar Abeta in a lysosomal pathway.

Alzheimer Disease↗
PubMedDate not supplied

Epidemiology of serum aminotransferase activities in the elderly.

BACKGROUND: Our study used data collected in Chung-Hsing Village in May 1998 to explore the distribution of serum aminotransferase activities and the relationship between aminotransferase and its related factors in the elderly. METHODS: All individuals aged 65 and over were recruited as study subjects. A total of 1093 persons, out of 1774 registered residents, were contacted by face-to-face interview. The response rate was 61.6 percent. However, only 586 subjects had blood tests and completed questionnaires. Analysis in this study was based on these 586 subjects. In order to study the significant related factors of abnormal aminotransferase activities, the t-test, ANOVA, chi-square analysis, and multivariate logistic regression were used. RESULTS: There were 66 percent men and 34 percent women. The mean age was 73.1 +/- 5.3 years. The mean values of aspartate aminotransferase (AST) were 29.3 +/- 14.5 u/l in men and 27.8 +/- 10.7 u/l in women (p > .05). The mean values of alanine aminotransferase (ALT) were 30.9 +/- 25.2 u/l in men and 26.3 +/- 12.6 u/l in women (p < .01). The abnormality rates of AST (> or = 40 u/l) were 10.5 percent in men and 12.2 percent in women (p > .05). The abnormality rates of ALT (> or = 40 u/l) were 16.7 percent in men and 12.6 percent in women (p > .05). After controlling for the other covariates, the multivariate logistic regression analysis showed that the significant related factor of abnormal AST was retirement status (odds ratio 4.4; 95 percent confidence interval = 1.5-13.3; p < .01). The significant related factors of abnormal ALT were obesity (odds ratio = 2.2; 95 percent confidence interval = 1.1-4.2; p < .05) and hypertriglyceridemia (odds ratio = 2.7; 95 percent confidence interval = 1.5-4.9; p < .01). CONCLUSIONS: We raise the hypothesis that evidence of liver disease with abnormal ALT may co-vary with other indicators of chronic diseases. A large-scale investigation will be suggested in the future to demonstrate the causal-effect issue between abnormal ALT and obesity or hypertriglyceridemia.

Aged↗