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Biomedical subjects

D G Lee

Publications and source records attributed to D G Lee.

48 records · Page 3Linked to original sources
PubMed1994

Expression of c-kit ligand in human keratinocytes.

The c-kit ligand is expressed on tissue-anchored stromal cells. It plays an important role in the development of c-kit-bearing cells, such as haematopoietic cells, germ cells, mast cells and melanocytes. In the present study, we used the reverse transcriptase-mediated polymerase chain reaction (PCR) technique to investigate whether human keratinocytes are able to express c-kit ligand mRNA. Two sets of primers were designed to distinguish two types of c-kit ligand mRNA (full-length type and spliced type). One set was used to amplify an 882-bp DNA fragment from the full-length type, and a 798-bp DNA fragment from the spliced type. Another set was used to amplify a 375-bp DNA fragment from the full-length type only. A cDNA fragment corresponding to the full-length type mRNA was amplified from a cDNA preparation of cultured human keratinocytes as well as from epidermis obtained by the suction blister technique. This result indicates the spontaneous transcription of full-length type mRNA of the c-kit ligand in human keratinocytes.

Epidermis↗
PubMed1992

Clinicopathologic and immunophenotypic study of non-Hodgkin's lymphoma in Korea. Lymphoreticular Study Group of the Korean Society of Pathologists.

This study sponsored by the Lymphoreticular Study Group of the Korean Society of Pathologists was carried out to provide nationwide data about the histopathologic-immunophenotypic features of malignant lymphomas in Korea. Two hundred and ninety Non-Hodgkin's lymphoma (NHL) among 312 malignant lymphomas collected from three representative areas in Korea were histologically reclassified. Two hundred and fifty three cases were immunohistochemically studied. T-cell lymphoma comprised 35.2% of NHL in this study and showed a quite comparable incidence to that of Japan and China, but it was much higher than in Western countries. A very low prevalence rate of the follicular variety (4.0%) and a higher propensity of primary extranodal involvement (60%) are additional characteristics of NHL in Korea. The most common histologic subtype of B cell lymphoma was diffuse large cell type, whereas the most common subtype of T cell lymphoma was diffuse mixed small and large cell type.

Adolescent↗
PubMed1991

Cross-cultural study of alcoholism: comparison between Kangwha, Korea and Yanbian, China.

A cross-cultural comparison study of alcohol use disorder between Kangwha and Yanbian was conducted using the Korean version of the Diagnostic Interview Schedule (DIS). The subjects of the two areas studied were all native Koreans but lived in different sociocultural environments. A significant difference in lifetime prevalence rate of alcohol abuse (Kangwha 16.48%, Yanbian 6.95%; p less than 0.05) and similarity of alcohol dependence (Kangwha 10.23%, Yanbian 11.50%; p less than 0.05) were found. Among a total of 21 items of alcoholic symptoms, 14 items showed significant differences in frequencies between the two areas. The authors have suggested that alcohol abuse and alcohol dependence are two different diagnostic categories in origin, alcohol abuse is more related to socio-cultural environment and alcohol dependence to biogenetic background. The authors have discussed the possible reasons for a higher prevalence rate of alcohol abuse in Kangwha compared to Yanbian.

Adolescent↗
PubMed1989

Dual effects of pertussis toxin on murine neutrophils in vivo. I. Pertussis toxin inhibits extravasation potential of mature neutrophils while simultaneously stimulating granulopoiesis.

Pertussis toxin (Ptx) has been employed as an adjuvant by many investigators to augment various types of cell-mediated and humoral immune responses. Recent work from our laboratory indicates that the exacerbation of delayed-type hypersensitivity (DTH) and contact hypersensitivity (CH) responses observed in Ptx-treated mice may be mediated by an absolute increase in the number of circulating neutrophils capable of migrating into tissue sites of antigen challenge. The purpose of the present study was to analyze the effects of Ptx on neutrophils and neutrophil function in vivo. Evidence is presented here suggesting that Ptx has both direct and indirect effects on neutrophils following its in vivo administration to normal mice. Mature neutrophils that are directly exposed to the actions of Ptx in vivo exhibit a marked reduction in their ability to extravasate into tissue sites of inflammation. These findings are consistent with those that have been reported following the exposure of isolated neutrophils to the effects of Ptx in vitro (i.e., that Ptx has an inhibitory effect on many of the functional capabilities of isolated neutrophils). Moreover, we have also determined that Ptx can affect the kinetics of neutrophil production indirectly through its ability to stimulate granulopoiesis. Ptx-exposed mice develop a protracted peripheral blood neutrophilia following toxin administration. Although the mechanism(s) involved in stimulating increased neutrophil production is presently unclear, both dexamethasone and indomethacin (cyclooxygenase pathway inhibitors) are able to function synergistically with Ptx to produce a markedly enhanced neutrophilia in exposed mice. We propose that the capacity of Ptx to augment CH and DTH responses and act as a potent adjuvant may relate, in part, to its ability to alter the rate of neutrophil production in vivo.

Animals↗
PubMed1986

Modulation of luteinizing hormone immunoreactivity and bioactivity by dopamine but not norepinephrine in women.

It has been suggested that changes in bioactive luteinizing hormone in women occur toward midcycle and may result in increased bioactive/immunoreactive luteinizing hormone ratios. To determine whether dopamine or norepinephrine modulate immunoreactive and bioactive luteinizing hormone secretion, 15 ovulatory women were studied in the mid to late follicular phase. Dopamine in two doses (0.5 micrograms/kg/min and 4 micrograms/kg/min) and norepinephrine, 0.1 microgram/kg/min, were infused for 4 hours, and metoclopramide, 10 mg intravenously, was also given to determine whether dopamine receptor antagonism results in changes. Bioactive luteinizing hormone and the bioactive/immunoreactive luteinizing hormone ratio increased in women from the early to late follicular phase (p less than 0.05). Both intravenous doses of dopamine resulted in significant decrements in immunoreactive luteinizing hormone (20 +/- 2 and 20 +/- 3%, p less than 0.02) and bioactive luteinizing hormone (36.7% and 43.2%, p less than 0.05). With dopamine there was also a significant decrease in the bioactive/immunoreactive luteinizing hormone ratio (p less than 0.02). Intravenous norepinephrine, however, resulted in no changes in either immunoreactive or bioactive luteinizing hormone levels. Metoclopramide also did not change immunoreactive or bioactive luteinizing hormone levels. These data suggest that although endogenous dopaminergic blockade may not play a significant role in determining basal levels of luteinizing hormone, decreases in dopamine at the pituitary level may increase the bioactive/immunoreactive luteinizing hormone ratio. Norepinephrine does not appear to exert major changes in immunoreactive or bioactive luteinizing hormone.

Adult↗
PubMedDate not supplied

Primary malignant fibrous histiocytoma of the liver: imaging features of five surgically confirmed cases.

BACKGROUND: The purpose of the present study was to describe the various imaging features of primary malignant fibrous histiocytoma (MFH) of the liver, a rare tumor of mesenchymal origin. METHODS: Sonography (n = 5), computed tomography (CT; n = 5), magnetic resonance (MR) imaging (n = 2), and hepatic arteriography (n = 3) in five patients who underwent partial hepatectomy for tumor resection were retrospectively reviewed and correlated with pathologic findings. RESULTS: All tumors were clearly demarcated from surrounding hepatic parenchyma in sectional imaging with (n = 2) or without (n = 3) a fibrous capsule, which was pathologically verified. Internal architecture of abundant fibrosis, myxoid degeneration, and/or hemorrhagic necrosis reflected the sonographic, CT and MR imaging findings. Marginal tumor staining without definite tumor vasculature was the main feature of hepatic arteriography. There was no intratumoral calcification. All three tumors involving the right lobe of the liver invaded the right hemidiaphragm. CONCLUSION: Although there were no unique findings of primary hepatic MFH, a combined interpretation of various imaging modalities may elucidate the malignant nature of the tumor.

Adult↗
PubMedDate not supplied

The role of neutrophils in tissue localized cell-mediated immunologic responses: I. The intensity of contact-type and delayed-type hypersensitivity responses may be influenced by the extent of extracellular matrix degradation by neutrophil proteases.

Studies were undertaken to evaluate factors capable of influencing the intensity of contact hypersensitivity (CH) and delayed-type hypersensitivity (DTH) responses in mice. It is well known that the exposure of animals to ultraviolet radiation (UVR) causes a depression of CH and DTH responses whereas the injection of mice with nanogram quantities of pertussis toxin (PT) before sensitization results in greatly augmented CH responses following hapten challenge. Histopathology and biochemical quantitation of myeloperoxidase (MPO) activity in biopsies obtained from the challenged ears from normal, UVR-exposed, or PT-treated animals determined that a direct correlation existed between the intensity of the ear-swelling response and the degree of neutrophil infiltrate into the challenge site. Few neutrophils were observed to infiltrate into the ears of UVR-exposed animals when compared to normal animals, whereas a pronounced neutrophil infiltration was observed in the challenged ears of PT-pretreated animals. These observations led us to question whether tissue-infiltrating neutrophils, or their products, might be involved in controlling the intensity of CH and DTH responses. The direct injection of murine neutrophils, neutrophil homogenates, and a neutrophil granular fraction into the ear pinnae of normal mice resulted in a dosage-dependent ear-swelling reaction after 24 hours that was histologically similar to antigen-induced CH or DTH responses (primarily mononuclear cell infiltrate). Additional studies determined that an injection of elastase, collagenase, or peptides of elastin or collagen generated by elastase or collagenase treatment of insoluble elastin or collagen also caused a pronounced ear-swelling accompanied by a mononuclear cell infiltration. On the basis of these studies, coupled to experiments that demonstrated an inhibitory influence of alpha-1-antitrypsin (alpha 1-AT) on CH and DTH responses, we propose that neutrophil proteases may play an important role in regulating the intensity of CH and DTH responses in mice through their capacity to degrade extracellular matrix proteins whose peptide fragments are chemotactic for mononuclear cells and fibroblasts.

Animals↗