Search PubMed⌕ Search

Biomedical subjects

K Kang

Publications and source records attributed to K Kang.

At least 73 records · Page 4Linked to original sources
PubMed1990

Difference in enzymatic sulfation of bile acids between the mouse and rat.

Species difference in bile acid-sulfotransferase (BAST) activity was studied between the mouse and rat. Cytosol fractions of the liver, kidney, small intestine and large intestine were incubated with bile acids and 3' phosphoadenosine-5'-phosphosulfate. The mouse liver showed BAST activity for lithocholic acid, taurolithocholic acid and taurochenodeoxycholic acid, whereas the rat liver and kidney had the activity for taurodeoxycholic acid in addition to these compounds. The highest activities were found in the mouse liver and rat kidney. The mouse small intestine showed weak activity only for lithocholic acid. No activity was found in other organs. BAST was inactive towards taurocholic acid, 7 alpha- or 12-monohydroxy-5 beta-cholanoic acid. Optimal pH of liver BAST in the two species was different from that of the rat kidney. BAST of the mouse liver showed the highest activity without addition of Mg2+, whereas that of the rat liver and kidney showed enhancement by exogenous Mg2+. These results indicated that the distribution and characteristics of mouse BAST was different from rat BAST. Such difference should be reminded in any animal study involving the two species.

Animals↗
PubMed1989

[The value of high-resolution computerized tomography in abnormalities of the middle ear].

Middle ear malformations are common congenital disorders of the head and neck area. Recent advances in plastic and middle ear surgery have improved the prognosis of patients suffering from congenital hearing disorders. However, sophisticated preoperative procedures are mandatory. The development of HR-CT has improved the radiologic possibilities to evaluate middle ear disorders significantly. In the present study we examined by means of HR-CT twenty patients with congenital middle ear malformation. Our findings include different sizes of the middle ear as well as dysplastic alterations of the malleus and incus. The inner ear was normal in almost all cases. Our results indicate that preoperative HR-CT is a reliable diagnostic method to demonstrate middle ear disorders.

Ear Ossicles↗
PubMed1989

[Radiologic diagnosis of the middle ear. Possibilities and perspectives].

During the past few years the importance of imaging methods for the diagnosis of head and neck diseases has increased significantly. Due to the rapid development of new techniques like "high-resolution" CT (HR-CT) and magnetic resonance imaging, radiology has become an important factor in the preoperative evaluation of many diseases in our discipline. The middle ear region in particular is known to be a complicated area and was often hard to interpret by radiological methods used so far. In the present paper the diagnostic value of HR-CT is demonstrated. Over the past two years we examined 130 patients suffering from middle ear diseases like malformations (MEM), otosclerosis, cholesteatoma and temporal bone fractures (TBF) with HR-CT. From our point of view the indications for this special examinations should be limited to MEM and TBF. The results and side effects of HR-CT and conventional tomography are compared and discussed. Finally, future perspectives of middle ear imaging are presented. Different reconstructive techniques have been developed during the past years, which might supply additional information for further questions arising in middle ear pathology in the future. At the present time none of these methods are ready for routine clinical use.

Ear Diseases↗
PubMed1989

Paragangliomas of the jugular bulb and carotid body: MR imaging with short sequences and Gd-DTPA enhancement.

Twenty-six patients with glomus jugulare (16), glomus tympanicum (three), or carotid glomus (seven) tumors were examined with contrast-enhanced CT scans and MR scans without and with Gd-DTPA. MR and CT scans had similar sensitivities, but the enhanced MR scans were diagnostically more specific than either CT or nonenhanced MR. Dynamic MR scanning permitted measurement of the degree of Gd-DTPA enhancement over time. We recommend contrast-enhanced MR with short sequences and a dynamic approach in patients with suspected carotid, tympanic, and jugular paragangliomas.

Carotid Body Tumor↗
PubMed1989

[Magnetic resonance tomography of the parotid gland: plain diagnosis and Gd-DTPA].

Pathological lesions of the parotid gland were examined comparatively with different examination sequences both plain and with the contrast medium Gd-DTPA. There were 36 benign lesions (parotitis, Sjögren's syndrome, adenoma, etc.) and 24 malignant tumours (squamous cell carcinoma, adenocarcinoma, adenoid cystic carcinoma etc.) Examinations were carried out at 1.0 T with long and short spin echo sequences in transverse and frontal layer orientation before and after application of Gd-DTPA as contrast medium. In the patients suffering from parotitis the best results were obtained with plain T1 and T2 sequences; the contrast medium Gd-DTPA remained without superior diagnostic relevance. However, in Sjögren's syndrome (myoepithelial sialadenitis) administration of the contrast medium always yielded a characteristic honeycomblike pattern. In benign and malignant space-occupying growths MRI supplied additional diagnostic information with Gd-DTPA in respect of defining the tumour borderlines and paths of infiltration. MRI is now a significant diagnostic tool in inflammatory and tumorous lesions of the parotid gland.

Adenocarcinoma↗
PubMed1985

Phosphodiesterase inhibition by Ro 20-1724 reduces hyper-IgE synthesis by atopic dermatitis cells in vitro.

Peripheral blood mononuclear leukocytes (MNL) from patients with atopic dermatitis spontaneously produce large amounts of IgE in vitro. These cells also show markedly elevated levels of cAMP phosphodiesterase (PDE) which may be responsible for the observed abnormal cAMP responsiveness. Treatment of atopic dermatitis MNL with varying concentrations of the cAMP PDE inhibitor Ro 20-1724 resulted in progressively decreasing amounts of IgE synthesis, statistically significant at the 10(-4) M and 10(-5) M concentrations. There was a close correlation between PDE inhibition and inhibition of IgE synthesis, r = 0.93, p less than 0.05. To define the cellular target of the drug, we used monoclonal antibodies directed toward MNL subsets (Lyt 3, OKT8, OKT4, monocyte-myeloid) in a modified "panning" method to perform experiments with purified subsets. With untreated subsets, removal of OKT4-positive cells significantly reduced IgE synthesis; readdition of OKT4-positive cells enhanced IgE synthesis. OKT8 cells and monocytes did not affect IgE synthesis. Pretreatment of T cell-depleted MNL with Ro 20-1724 resulted in significantly more inhibition of IgE synthesis than did pretreatment of T enriched cells prior to recombination with the reciprocal untreated subset and subsequent culture. Similarly, pretreatment of monocyte-depleted cells resulted in significantly more inhibition of IgE synthesis than pretreatment of monocyte-enriched cells prior to recombination and culture. The majority of the effect appeared to be mediated by a direct effect on the B cells. However, some inhibition of IgE synthesis was also achieved through pretreatment of T enriched cells. Since pretreatment of isolated suppressor/cytotoxic or helper/inducer T-cell subsets did not give the same degree of inhibition as with unfractionated T cells, a T-T interaction may be involved in this aspect. The imidazolidinone derivative, Ro 20-1724, significantly and consistently inhibited both the elevated cAMP phosphodiesterase activity and the elevated spontaneous IgE synthesis of MNL from patients with atopic dermatitis. These findings demonstrate a previously undescribed link between cAMP PDE levels and in vitro IgE synthesis.

4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone↗
PubMed1984

Direct depletion and purification of monoclonal antibody defined cells from unfractionated human mononuclear leukocytes using antibody coated polystyrene Petri dishes.

Human peripheral blood mononuclear leukocytes were depleted or enriched in various monoclonal antibody-defined subsets using a simplification of the indirect " panning " technique. Unfractionated mononuclear leukocytes (MNL) were sensitized with appropriate dilutions of monoclonal antibodies to human Lyt3 , OKT4 and OKT8 antigens, and to a monocyte-myeloid line antigen. The sensitized cells were then placed on polystyrene Petri dishes coated with goat antimouse IgG to obtain a population of cells depleted and a population of cells enriched in each cell type. Direct separation of surface immunoglobulin-bearing cells was similarly achieved by coating the Petri dish with goat antihuman immunoglobulins. Results showed that MNL could be depleted to greater than 95% purity with these methods and that positively selected adherent cells could be enriched to at least 85% purity. The relative proportions of MNL subpopulations in various sorted cell populations is reported. Cells obtained by panning are functionally intact. As compared to complement lysis both marker positive and marker negative cells can be obtained and the technique requires less technical expertise than using fluorescence activated cell sorting. The modification reported here is simpler and less time consuming for human T cell subpopulation separations than previously reported panning methods since an initial sheep erythrocyte rosetting step was not used.

Animals↗
PubMed1983

Thymopoietin pentapeptide (TP-5) improves clinical parameters and lymphocyte subpopulations in atopic dermatitis.

In a double-blind prospective study, eighteen patients with atopic dermatitis (AD) were treated with thrice-weekly injections of 50 mg thymopoietin pentapeptide (TP-5) or placebo for 6 weeks. Clinical parameters, lymphocyte subsets defined by monoclonal antibodies, and serum IgE were modified. Younger patients (age less than 34) responded to TP-5 with much greater improvement in severity scores than TP-5-treated patients of age greater than 34 or than placebo-treated patients of either age group (p less than 0.05). Both absolute lymphocytes and OKT8+ cytotoxic/suppressor cells were significantly increased (p less than 0.05) in the TP-5 group, whereas they were not significantly increased in the placebo group (p greater than 0.05). Conversely, Ia+ cells were significantly increased in the placebo group (p less than 0.05), but remained the same in the TP-5 group (p greater than 0.05). Serum IgE levels were not significantly altered in either group. Thus, TP-5 had a beneficial clinical effect in AD, especially in younger patients, and increased the reduced OKT8+ cytotoxic/suppressor T cells and prevented an increase of Ia+ cells during pollen season.

Adult↗