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Biomedical subjects

C Chung

Publications and source records attributed to C Chung.

At least 109 records · Page 6Linked to original sources
PubMed1981

Effect of vitamin E on cell-mediated immune responses and serum corticosterone in young and maturing mice.

A high vitamin E diet altered cell-mediated immune responses of maturing BALB/c mice. Serum corticosterone concentrations in these animals were also determined because of the pharmacological effect the glucocorticoid hormone has on immune systems. Mice receiving high vitamin E diet (twenty times higher than the vitamin E concentration in control diet) showed significant increase in antibody-dependent cellular cytotoxicity (ADCC) activity within a week after initiation of the diet. Adult levels of spleen and intestinal ADCC activities were reached at a much younger age in these high vitamin E-treated animals. In addition, there was a good correlation between increase in spleen and intestinal ADCC activities and the significantly lower than control concentration of serum corticosterone in these mice. However, after prolonged consumption of high vitamin E diet, decrease in ADCC activity was observed in these mice. No significant differences in PHA-induced spleen lymphocytes [3H]-thymidine incorporation, along with a decrease in serum corticosterone levels, were observed in mice given either high vitamin E or the control diets throughout most study periods.

Animals↗
PubMed1980

Interferon production by individual L cells.

Using a protected centre technique in which agarose prevents the diffusion of interferon from individual producing cells, we have shown that essentially every cell in a monolayer of mouse L cells can be induced to produce interferon by infection with Newcastle disease virus (NDV). The amount of interferon produced by individual cells appeared to be highly variable, even when cloned cells and viruses were used. U.v.-irradiated virus lost its capacity to induce interferon in L cells and to infect chick embryo fibroblasts at the same rate. A small proportion of cells (1 X 10-6 to 10 X 10-6) appeared to produce interferon constitutively. This fraction was increased threefold by u.v. irradiation of the cells, and up to 10-fold by exposing cells to the mutagen ethyl methane sulphonate.

Animals↗
PubMed1980

Protein kinases in chronic lymphocytic leukemia.

Experiments were performed to characterize the protein kinase activity in blood lymphocytes from patients with chronic lymphocytic leukemia (CLL). Using histone as a substrate, the average specific activity was 397 pmole/min/mg protein. The Km for ATP was 8 muM and for histone 0.3 mg/ml. The addition of optimal concentrations of cyclic adenosine monophosphate (cAMP) (1 muM) or cyclic guanosine monophosphate (cGMP) (10muM) resulted in a 2.2-fold stimulation in activity but had no effect on the Km for ATP or histone. Most of the properties of the CCL protein kinase were similar to those of the normal lymphocyte enzyme. These include the pH response, substrate affinity, as well as rates of phosphorylation and dephosphorylation. The phosphorylation pattern of endogenous proteins was determined using intact lymphocytes incubated with 32P and cell-free homogenates with AT32P. These results indicate that: (1) the cyclicnucleotide-protein kinase interactions are unimpaired in CLL lymphocytes; and (2) a sharply defined cyclic nucleotide concentration response occurs for CLL (as well as normal) lymphocytes, which may explain the reports of variable inhibitory (and stimulatory) effects on mitogenesis by these agents.

Cyclic AMP↗
PubMed1977

Combination chemotherapy and radiotherapy in small-cell carcinoma of the lung.

A combination of chemotherapy (Cytoxan, vincristine, and CCNU) and radiation therapy was used to treat 37 patients with small-cell carcinoma of the lung. There was 49% complete remission and an overall 76% objective response with an overall median survival of 12.5 months and 17 months for those showing a complete response. No serious morbidity was observed.

Carcinoma, Small Cell↗
PubMedDate not supplied

Purification of heart and liver mitochondrial carnitine acetyltransferase.

Heart and liver mitochondrial, as well as liver peroxisomal, carnitine acetyltransferase was purified to apparent homogeneity and some properties, primarily of heart mitochondrial carnitine acetyltransferase, were determined. Hill coefficients for propionyl-CoA are 1.0 for each of the enzymes. The molecular weight of heart mitochondrial carnitine acetyltransferase, determined by SDS-PAGE, is 62,000. It is monomeric in the presence of catalytic amounts of substrate. Polyclonal antibodies against purified rat liver peroxisomal carnitine acetyltransferase precipitate liver and heart mitochondrial and liver peroxisomal carnitine acetyltransferase, but not liver peroxisomal carnitine octanoyltransferase. Liver peroxisomes, mitochondria, and microsomes and heart mitochondria all give multiple bands on Western blotting with the antibody against carnitine acetyltransferase. Major protein bands occur at the molecular weight of carnitine acetyltransferase and at 33 to 35 kDa.

Animals↗
PubMedDate not supplied

Glioblastoma multiforme metastatic to the neck.

Glioblastoma multiforme, a rapidly growing intracranial neoplasm, rarely metastasizes unless operated upon, and even after surgical exposure metastasis is uncommon unless the patient is a long-term survivor. The most likely site of metastasis is the cervical lymph nodes. A patient developed a rapidly expanding cervical metastasis a year after surgery and irradiation for the primary. The 6-cm neck mass responded dramatically to radiation therapy and lomustine. The patient is clinically without evidence of progression of disease 20 months after the initial diagnosis, and there is no palpable recurrence in the neck. It is recommended that the patient who has a cervical mass and a history of surgically treated glioblastoma multiforme undergo a careful otolaryngologic examination prior to open biopsy. In general, such a patient can be spared an extensive "unknown primary" evaluation before biopsy.

Adult↗
PubMedDate not supplied

Gd-DTPA MR detection of blood-brain barrier opening in rats after hyperosmotic shock.

OBJECTIVE: Detection of blood-brain barrier (BBB) opening in neonates has required invasive methods not clinically applicable. We set out to develop a noninvasive approach to detect such opening. MATERIALS AND METHODS: Wistar rats were studied using MRI with Gd-DTPA contrast before and after injection of hyperosmotic solutions known to produce barrier opening. Arabinose was given via right carotid artery to produce unilateral barrier opening; urea was given via tail vein to produce bilateral opening; controls received normal saline. Next, all animals received Gd-DTPA via tail vein. RESULTS: Animals receiving carotid hyperosmotic injections showed increased signal in the ipsilateral brain hemisphere; those receiving venous hyperosmotic injections showed increased signal bilaterally. Similar increases were not found prior to administration of hyperosmotic agent or in saline controls. In both cases, barrier opening was detectable using the relative partitioning of Gd-DTPA between intrabarrier and extrabarrier structures, even in the absence of a hemispheric control. CONCLUSION: We conclude that MRI with Gd-DTPA contrast allows noninvasive detection of BBB opening in the rat.

Animals↗
PubMedDate not supplied

Psychometric testing of the depressive cognition scale in women with type 2 diabetes.

Depression is prevalent in young and middle-aged diabetic women. Although cognitive depressive symptoms precede the development of depression, there is no screening instrument to measure these symptoms in diabetic patients. This study tested the psychometric properties of the Depressive Cognition Scale (DCS) in a convenience sample of 83 women with Type 2 diabetes. Alpha coefficient for the 8-item scale was .85, and the average inter-item correlation coefficient was .42. Construct validity was supported by correlations in the expected directions between the DCS and measures of learned resourcefulness, depressive symptoms, and health practices. Factor analysis presented a single dimension of 8 items. These findings suggest that the DSC will be useful in identifying patients with chronic conditions such as diabetes who are at risk for the development of clinical depression.

Adult↗
PubMedDate not supplied

Mandatory pharmacosurveillance--a Canadian model for access to therapy and research.

Regulatory authorities in Canada have expressed a vital need for pharmacoepidemiological data on long-term effectiveness, safety, and cost-benefit of new therapies, particularly in comparison to currently available therapies, in routine clinical practice to allow informed decision making in listing new therapies on formulary. We describe the evolution of a new model of pharmacosurveillance involving a partnership between academic and community rheumatologists, government, and industry whereby access to therapy is conditional on participation in an industry-funded pharmacosurveillance study that assesses long-term effectiveness, safety, and cost-benefit. Though funded by industry, the program is administered by government and designed and operated at arms length from industry. The clinic data sheets are available at www. altarheum.com. The program also provides a sustainable model for promoting observational research on therapeutics in general.

Antirheumatic Agents↗
PubMedDate not supplied

Leg ulcers in patients with sickle cell disease.

Chronic leg ulcers may result from vasoocclusive complications associated with the decreased oxygen-carrying capacity of hemoglobin in patients with sickle cell disease or its variants. Nonsurgical management includes the use of anti-sickling drugs and chemical manipulation of the hemoglobin composition. It has been suggested that the use of recombinant human erythropoietin (r-HuEPO) may help by stimulating proliferation of red blood cell precursors; it also has been proposed that r-HuEPO may act as a growth factor to non-hematologic tissues. Surgical management is a choice of last resort, often requiring microsurgical techniques, such as free-flap transfer.

Anemia, Sickle Cell↗