Biomedical subjects

Sung Han Kim

Publications and source records attributed to Sung Han Kim.

11 recordsLinked to original sources

PubMed2006

Comparative effect of gromwell (Lithospermum erythrorhizon) extract and borage oil on reversing epidermal hyperproliferation in guinea pigs.

To compare the systemic efficacy of borage oil (Borago officinalis: BO) and gromwell (Lithospermum erythrorhizon), two plant species of the Boraginaceae family, epidermal hyperproliferation was induced in guinea pigs by a hydrogenated coconut oil diet for 8 weeks. Subsequently, guinea pigs were fed diets of BO (group HBO), organic extract (group HGO), or water extract (group HGW) of gromwell for 2 weeks. In groups HGO and HGW, proliferation scores and the level of ceramides, the major lipid maintaining epidermal barrier, were similar with those in normal control group BO fed BO diet for 10 weeks. Despite accumulation of 15-hydroxyeicosatrienoic acid (15-HETrE), the potent anti-proliferative metabolite of gamma-linolenic acid (GLA: major polyunsaturated fatty acid in BO), the reversal of epidermal hyperproliferation and the ceramide level of group HBO were less than those of groups HGO and HGW. Taken together, our data demonstrate that gromwell is more effective in reversing epidermal hyperproliferation with a marked increase in ceramides.

Animals↗

PubMed2006

Synthesis of 13-(substituted benzyl) berberine and berberrubine derivatives as antifungal agents.

By introducing various aromatic groups in 13-C of berberine and berberrubine, a series of 13-(substituted benzyl) berberine and berberrubine derivatives were synthesized and examined for antifungal activities against various human pathogenic fungi. The synthesized compounds exhibited more potent antifungal activities than berberine and berberrubine. Among them, 13-(4-isopropyl benzyl) berberine (6e) exerted the most potent antifungal activities against Candida species (MIC=1-8 microg/ml) and a 4-fold stronger activity than 13-(4-isopropyl benzyl) berberrubine (7e) synthesized by pyrolysis of compound 6e.

Antifungal Agents↗

PubMed2006

N-Benzylbenzamides: a new class of potent tyrosinase inhibitors.

A series of potent inhibitors of tyrosinase and their structure-activity relationships are described. N-Benzylbenzamide derivatives (1-21) with hydroxyl(s) were synthesized and tested for their tyrosinase inhibitory activity. With this series, compound 15 provided a potent tyrosinase inhibition: it effectively inhibited the oxidation of l-DOPA catalyzed by mushroom tyrosinase with an IC(50) of 2.2microM.

Benzamides↗

PubMed2004

Anticancer activity of 3-O-acyl and alkyl-(-)-epicatechin derivatives.

By changing the structure or replacing the gallate group of (-)-ECG, 3-O-acyl and alkyl-(-)-epicatechin derivatives were synthesized to be screen as anticancer agents using the MTT assay in vitro against cancer cell lines (PC3, SKOV3, U373MG). 3-O-Acyl and alkyl-(-)-epicatechin derivatives (4-25) exhibited better anticancer activity than (-)-ECG and specially, compounds 6-8, 17-19, which were modified aliphatic chains with moderate sizes (C8-C12) showed strong anticancer activity (IC50=6.4-31.2 microM). The introduction of an alkyloxy group on 3-O-hydroxyl instead of an acyloxy group significantly enhanced inhibitory activity. Consequently, the compound that showed the most potency as anticancer agents were 3-O-decyl-(-)-epicatechin (18) (IC50=8.9, 7.9, 6.4 microM against PC3, SKOV3, U373MG, respectively), which modified the appropriate lipophilic group on the C-3 hydroxyl as an alkyloxy group.

Antineoplastic Agents↗

PubMed2004

Antimicrobial activity of 3-O-acyl-(-)-epicatechin and 3-O-acyl-(+)-catechin derivatives.

As an exploratory investigation of antimicrobial promoting compounds, 3- O-acyl-(-)-epicatechins and 3- O-acyl-(+)-catechins possessing various aromatic groups and aliphatic chains of varying length from C4 to C16 for increasing lipophilicity were synthesized and tested for antimicrobial activities against Gram-positive, Gram-negative bacteria and fungi. The (-)-epicatechin and (+)-catechin derivatives comprised of aromatic groups increased activity and derivatives with acyl chain groups of carbon atoms in the close vicinity of C8 to C10 showed strong antimicrobial activity (MIC = 2 - 8 microg/ml) against Gram-positive bacteria and weak activity against fungi. However, the activity decreased when the carbon chain length of the substituents was too short (C4 to C6) or too long (C16). These results suggest that the presence of lipophilic substituents with moderate sizes might be crucial for the optimal antimicrobial activity.

Anti-Infective Agents↗

PubMed2004

A high frequency of macrolide-lincosamide-streptogramin resistance determinants in Staphylococcus aureus isolated in South Korea.

Genes conferring resistance to one of the macrolide-lincosamide-streptogramin (MLS) antibiotics may confer cross-resistance to others, because they have similar effects on bacterial protein synthesis. In Korea, over 70% of Staphylococcus aureus isolates are methicillin-resistant and erythromycin-resistant methicillin-resistant S. aureus (MRSA) is also prevalent. We investigated the frequency of MLS resistance in erythromycin-resistant S. aureus isolates. A total of 682 isolates of S. aureus were collected in a nationwide antibiotic resistance survey. Susceptibility to erythromycin, clindamycin, and quinupristin/dalfopristin was tested by disk diffusion. In all, 37% of the methicillin-susceptible S. aureus (MSSA) and 97% of the MRSA isolates were resistant to at least one of the MLS antibiotics, whereas all were susceptible to quinupristin/dalfopristin. Out of 518 strains that were resistant to erythromycin, 60 clindamycin-susceptible (30 MSSA, 30 MRSA) and 44 clindamycin-resistant isolates (14 MSSA, 30 MRSA) were selected at random from these strains. Thirteen genes related to MLS resistance were detected in these isolates by PCR. Of the 104 MSSA and MRSA strains tested, 98 harbored one or more erm gene. The most common was erm(A), with erm(C) next. But, msr(A), lnu(A), and mef(A) were rare and no resistance to streptogramin A was encountered.

Anti-Bacterial Agents↗

PubMed2003

Rational design of an indolebutanoic acid derivative as a novel aldose reductase inhibitor based on docking and 3D QSAR studies of phenethylamine derivatives.

A series of 45 phenethylamine derivatives were synthesized and evaluated for their inhibitory activity against pig kidney aldose reductase (ALR2, EC 1.1.1.21). Their IC(50) values ranged from 400 microM to 24 microM. The binding modes of compounds at the active site of ALR2 were examined using flexible docking. The results indicated that phenethylamine derivatives nicely fit into the active pocket of ALR2 by forming various hydrogen bonding and hydrophobic interactions. 3D-QSAR analysis was also conducted using FlexX-docked alignment of the compounds. The best prediction was obtained by CoMSIA combined with hydrophobic and hydrogen bond donor/acceptor field (q(2) = 0.557, r(2) = 0.934). A new derivative, 4-oxo-4-(4-hydroxyindole)butanoic acid, was designed, taking into account the CoMSIA field and the binding mode derived by FlexX docking. This rationally designed compound exhibits an ALR2 inhibition with an IC(50) value of 7.4 microM, which compares favorably to that of a well-known ALR2 inhibitor, tolrestat (IC(50) = 16 microM) and represents a potency approximately 240-fold higher than that of an original phenethylamine lead compound, YUA001.

Aldehyde Reductase↗

PubMed2003

Mice deficient in alpha-actinin-4 have severe glomerular disease.

Dominantly inherited mutations in ACTN4, which encodes alpha-actinin-4, cause a form of human focal and segmental glomerulosclerosis (FSGS). By homologous recombination in ES cells, we developed a mouse model deficient in Actn4. Mice homozygous for the targeted allele have no detectable alpha-actinin-4 protein expression. The number of homozygous mice observed was lower than expected under mendelian inheritance. Surviving mice homozygous for the targeted allele show progressive proteinuria, glomerular disease, and typically death by several months of age. Light microscopic analysis shows extensive glomerular disease and proteinaceous casts. Electron microscopic examination shows focal areas of podocyte foot-process effacement in young mice, and diffuse effacement and globally disrupted podocyte morphology in older mice. Despite the widespread distribution of alpha-actinin-4, histologic examination of mice showed abnormalities only in the kidneys. In contrast to the dominantly inherited human form of ACTN4-associated FSGS, here we show that the absence of alpha-actinin-4 causes a recessive form of disease in mice. Cell motility, as measured by lymphocyte chemotaxis assays, was increased in the absence of alpha-actinin-4. We conclude that alpha-actinin-4 is required for normal glomerular function. We further conclude that the nonsarcomeric forms of alpha-actinin (alpha-actinin-1 and alpha-actinin-4) are not functionally redundant. In addition, these genetic studies demonstrate that the nonsarcomeric alpha-actinin-4 is involved in the regulation of cell movement.

Actinin↗

PubMed2003

Disseminated cryptococcosis in a patient with pituitary Cushing's disease.

Disseminated cryptococcosis mainly occurs in patients with cell-mediated immunity disorders. A case of disseminated cryptococcosis, in a patient with pituitary Cushing's disease, is reported. Cultures of blood, cerebrospinal fluid (CSF) and aspirates of a skin lesion all grew Cryptococcus neoformans. Despite antifungal treatment, with amphotericin-B, the patient died within 3 weeks.

Amphotericin B↗

PubMed2002

Antimicrobial activity of 9-O-acyl- and 9-O-alkylberberrubine derivatives.

For the structure-activity relationship study on berberrubine derivatives, a series of compounds bearing 9-O-acyl- and 9-O-alkyl-substituents were synthesized and tested for antimicrobial activity against Gram-positive, Gram-negative bacteria and fungi. Octanoyl, decanoyl, lauroyl derivatives among the acyl analogs and hexyl, heptyl, octyl, nonyl, decyl, undecyl derivatives among the alkyl analogs showed strong antimicrobial activity against Gram-positive bacteria and fungi. As a whole, alkyl analogs were more active than acyl analogs for antimicrobial activity. Synthesized derivatives had no activity on Gram-negative bacteria. Too short or too long substituents decreased activity. These results suggest that the presence of lipophilic substituents with moderate sizes might be crucial for the optimal antimicrobial activity.

Anti-Bacterial Agents↗

PubMed2002

Chylothorax in Gorham's disease.

A 25-yr-old woman presented with a right pleural effusion. Destruction of 9th through 12th ribs, adjacent vertebral bodies, and transverse processes was noted on plain radiograph and a large low-attenuated, irregular shaped mass lesion with peripheral rim enhancement, destroying vertebral body and transverse process, was revealed on the computed tomographic scan. Magnetic resonance imaging showed high signal on T1- weighted image and iso- and low signal on T2-weighted image for the mass lesion replacing the vertebral bony cortex and marrow space. An open rib biopsy revealed the histopathological changes of Gorham's disease (essential osteolysis), even though only bloody fluid filling the empty space and rib and vertebral transverse process destruction were grossly observed on operation. Even though there was no definite response to radiotherapy and pleurodesis, the patient showed stable condition up to 20 months after diagnosis.

Adult↗