Type I diabetes, also known as insulin-dependent diabetes mellitus (IDDM) results from the destruction of insulin-producing pancreatic $\beta$ cells by a progressive $\beta$ cell-specific autoimmune process. The pathogenesis of autoimmune IDDM has been extensively studied for the past two decades using animal models such as the non-obese diabetic (NOD) mouse and the Bio-Breeding (BB) rat. However, the initial events that trigger the immune responses leading to the selective destruction of the $\beta$ cells are poorly understood. It is thought that $\beta$ cell auto-antigens are involved in the triggering of $\beta$ cell-specific autoimmunity. Among a dozen putative $\beta$ cell autoantigens, glutamic acid decarboxylase (GAD) has bee proposed as perhaps the strongest candidate in both humans and the NOD mouse. In the NOD mouse, GAD, as compared with other $\beta$ cell autoantigens, provokes the earliest T cell proliferative response. The suppression of GAD expression in the $\beta$ cells results in the prevention of autoimmune diabetes in NOD mice. In addition, the major populations of cells infiltrating the iselts during the early stage of insulitis in BB rats and NOD mice are macrophages and dendritic cells. The inactivation of macrophages in NOD mice results in the prevention of T cell mediated autoimmune diabetes. Macrophages are primary contributors to the creation of the immune environment conducive to the development and activation of $\beta$cell-specific Th1-type CD4+ T cells and CD8+ cytotoxic T cells that cause autoimmune diabetes in NOD mice. CD4+ and CD8+ T cells are both believed to be important for the destruction of $\beta$ cells. These cells, as final effectors, can kill the insulin-producing $\beta$ cells by the induction of apoptosis. In addition, CD8+ cytotoxic T cells release granzyme and cytolysin (perforin), which are also toxic to $\beta$ cells. In this way, macrophages, CD4+ T cells and CD8+ T cells act synergistically to kill the $\beta$ cells in conjunction with $\beta$ cell autoantigens and MHC class I and II antigens, resulting in the onset of autoimmune type I diabetes.

In ginsenoside Rh2-treated rat glioma C6Bu-1 cells, apoptotic morphological changes, such as cell shrinkage, chromatin condensation and pyknosis were confirmed by means of electron microscopy. To evaluate whether induction of apoptosis by ginsenoside Rh2 is mediated by the members of Bcl-2 family, we first established C6Bu-1 cells overexpressing Bcl-2. It was demonstrated that the expression of Bcl-2, Bcl-xL, and Bax was not altered in ginsenoside Rh2-treated C6Bu-1 overexpressing C6Bu-1 cells failed to prevent from ginsenoside Rh2-induced cell death. These results suggest the existence of other apoptotic pathway that requires induction of apoptosis by ginsenoside Rh2 rather than the pathway through Bcl-2, $Bcl-x_{L}$ or Bax in C6Bu-1 cells.

TR8 is a recently identified member of the tumor necrosis factor (TNF) receptor superfamily. TR8 seems to play important roles in bone metabolism as stimulation of this receptor with its ligand, TL8 or osteoclast differentiation factor (ODF), induced the differentiation and activation of osteoclasts. Despite its important biological functions, the biochemcial events ensuing form TR8 activation have not been revealed in detail. Most of TNF receptor family proteins provoke the activation of the NF-$textsc{k}$B transcription factor. In the present study, we examined the signaling potential of TR8 to induce NF-B activation. When overexpressed in a human embryonic kidney cell line by transient transfection, TR8 caused a strong activation of NF-$textsc{k}$B, which was further increased upon stimulation with TL8. The TR8-induced NF-B activation was abrogated by the co-expression of the TRAF6 mutnat lacking the Ring and zinc finger domains and that of the kinase-inactive mutant NIK. Taken together, our study suggests that the presence of intact TRAF6 and the kiase activity of NIK may be essential for TR8 to induce NF-$textsc{k}$B activation.

The effects of the hindered and non-hindered water soluble long-chain disulfide bonds on the stability and cytotoxicity of the ricin A chain (RTA) immunotoxin were examined. The RTA immunotoxins were prepared with the Fab fragments of anti-common acute lymphoblastic leukemia antigen (CALLA) monoclonal antibody (Fab-RTA) using sulfosuccinimidyl-6-[(-methyl-(-2-pyridyldithio)toluamido]toluamido]hexanoate (S-LC-SMPT) and sulfosuccinimidyl-6-[3-(2-pyridyldithio-propionamido]hexanoate (S-LC-SPDP). The prepared Fab-RTA immunotoxins were evaluated for their conjugation yield, immunoreactivity, thermal and disulfide bond stability and cytotoxicity. The conjugation yield of the Fab-RTA immunotoxin from the water soluble long chain crosslinking agents, S-LC-SMPT and S-LC-SPDP, were comparable. Both Fab-RTA immunotoxins exhibited a similar immunoreactivity and thermal stability in aqueous solution. However, S-LC-SMPT -mediated Fab-RTA, sterically hindered, showed an enhanced disulfide bond stability in vitro over S-LC-SPDP mediated one. In the cytotoxicity against antigenic cell Daudi, the S-LC-SMPT -mediated RTA immunotoxin maintained a comparable cytotoxicity, compared with S-LC-SPDP mediated Fab-RTA immunotoxin.

Regulation of phosphcholine-hydrolyzing phosphatase (phosphocholine-phosphatase) activity, purified from bovine brain, was examined under physiological conditions. Various endogenous phosphomonoesters, which were utilized as substrate, inhibited the phosphocoline-phosphatase activity competitively (Ki 5.5-$82.0 {\mu}M$); among phosphomonoesters tested, there was a similar order of capability between the binding affinity of substrate and the inhibitory potency. In addition, phosphate ions also inhibited the phosphatase activity competitively with a Ki value of approximately $16{\mu}M$. Although leucine or theophylline inhibited the phosphatase activity at pH 9.0, their inhibitory action decreased greatly at pH 7.4. The pH-Km and pH-Vm profiles indicate that ionizable amino acids are involved in substrate binding as well as catalysis, alluding that the phosphatase activity may be highly dependent on the intracellular pH. Amino acid modification study supports the existence of tyrosine, arginine or lysine residue in the active site, and the participation of tyrosine residue in the catalytic action may e suggested positively for the susceptibility to the action of tetranitromethane or HOl-generator. Separately, the oxidative inactivation of phosphocholine-phosphatase activity was investigated. Of oxidants tested, HOONO, HOCl, HOl and $ascorbate/Cu^{2+}$ system were effective to inactivate the phosphatase activity. Noteworthy, a remarkable inativation was accomplished by $30{\mu}M$ HOCl in combination with 1 mM Kl. Inaddition, $Cu^{2+}(3{\mu}M) $in combination with ascorbate at concentrations as low as 0.1-0.3 mM reduced the phosphatase activity to a great extent. From these results, it is proposed that the phosphocholine-phosphatase activity may be regulated endogenously and susceptible to the various oxidant system in vivo.

Modulation of unscheduled DNA synthesis by dehydroepiandrosterone (DHEA) after exposure to various chemical carcinogens was investigated in the primary rat hepatocytes. Unscheduled DNA synthesis was induced by treatment of such direct acting carcinogens as methly methanesulfonate (MMS) and ethyl methanesulfonate (EMS) or procarcinogens including benzo(a)pyrene (BaP) and 7, 12-dimethylbenz(a)anthracene (DMBA). Unscheduled DNA synthesis was determined by measuring [methyl-3H]thymidine radioactivity incorporated into nuclear DNA of hepatocytes treated with carcinogens in the presence or absence of DHEA. Hydroxyurea $(5{\times}10^{-3} M)$was added to growth medium to selectively suppress normal replication. DHEA at concentrations ranging from $(1{\times}10^{-6} M)$ to$(5{\times}10^{-4} M)$ did not significantly inhibit unscheduled DNA synthesis induced by either MMS $(1{\times}10^{-4} M)$ or EMS $(1{\times}10^{-2} M)$. In contrast, DHEA-significantly inhibited unscheduled DNA synthesis induced by BaP $(6.5{\times}10^{-5} M)$ and DMBA.$(2{\times}10^{-5} M)$. DHEA-induced hepatotoxicity in rats was examined using lactate dehydrogenase (LDH) release as an indicator of cytotoxicity. DHEA exhibit no significant increase in LDH release compared with the control at 18 h. These data suggest that nontoxic concentration of DHEA does not affect the DNA excision repair process, but it probably influence the enzymatic system responsible for the metabolic activation of procarcinogens and thereby decreases the amount of the effective DNA adducts formed by the ultimate reactive carcinogenic species.

In this study, the effects of ursodeoxycholic acid (UDCA) on ischemia/reperfusion injury were investigated on isolated heart perfusion model. Hearts were perfused with oxygenated Krebs-Henseleit solution (pH 7.4, $37^{\circ}C$) on a Langendroff apparatus. After equilibration, isolated hearts were treated with UDCA 20 to 160 $\mu$M or vehicle (0.04% DMSO) for 10 min before the onset of ischemia. After global ischemia (30 min), ischemic hearts were reperfused and allowed to recover for 30 min. The physiological (i.e. heart rate, left ventricular developed pressure, coronary flow, double product and time to contracture formation) and biochemical (lactate dehydrogenase; LDH) parameters were evaluated. In vehicle-treated group, time to contracture formation was 21.4 min during ischemia, LVDP was 18.5 mmHg at the endpoint or reperfusion and LDH activity in total reperfusion effluent was 54.0 U/L. Cardioprotective effects of UDCA against ischemia/reperfusion consisted of a reduced TTC $(EC_{25}=97.3{\mu}M)$, reduced LDH release and enhanced recovery of cardiac contractile function during reperfusion. Especially, the treatments of UDCA 80 and $160 {\mu}M $ significantly increased LVDP and reduced LDH release. Our findings suggest that UDCA ameliorates ischemia/reperfusion-induced myocardial damage.

The mechanism of action of fish oil (FO), currently used in different chronic inflammatory conditions such as rheumatoid arthritis (RA), is not completely understood, although it is thought that it could alter the metabolism of endogenous autacoids. In addition, we hypothesized that the known capability of fatty acids (FA) of stabilizing serum albumin and perhaps other proteins, may be of pharmacological relevance considering that it is shared by other anti-rheumatic agents (e.g. nonsteroidal antiinflammatory drugs). Thus, we studied the effect of oral administration of FO and corn oil (CO), a vegetable oil with a different composition, on the stability of rat serum proteins, evaluated buy a classical in vitro method based on heat-induced protein denaturation. FO, and, to a lower extent, CO inhibited heat-induced denaturation of rat serum (RS): based on the inhibitory activity (EC50) of the major fatty acids against heat-induced denaturation of RS in vitro, it was possible to speculate the in vivo effects of palmitic acid (C16:0) and eicosapentaenoic acid (EPA, C20:5, n-3) may be more relevant than that of linolenic acid (C18:2). To better investigate this phenomenon, we extracted albumin from the serum of animals treated or not with FO with a one-step affinity chromatography technique, obtaining high purity rat serum albumin preparations (RSA-CTRL and RSA-FO), as judged by SDS-PAGE with Coomassie blue staining. When these RSA preparations were heated at $70^{\circ}C$ for 30 min, it was noted that RSA-FO was much more stable than RSA-CTRL, presumably due to higher number of long chain fatty acids (FA) such as palmitic acid or EPA. In conclusion, we provided evidences that oral administration of FO in the rat stabilizes serum albumin, due to an increase in the number of protein bound long chain fatty acids (e.g. palitic acid and EPA). We speculate that the stabilization of serum albumin and perhaps other proteins could prevent changes of antigenicity due to protein denaturation and glycosylation, which may trigger pathological autoimmune responses, suggesting that this action may be involved in the mode of action of FO in RA and other chronic inflammatory diseases.

In order to examine the effects of N-substituted alkyl group on the anticonvulsant activities of N-Cbz-$\alpha$-aminoglutarimides as novel anticonvulsants with broad spectrum, a series of (R) or (S) N-Cbz-$\alpha$-amino-N-alkylglutarimides (1 and 2) were prepared from the corresponding (R) or (S) N-Cbz-glutamic acid and evaluated for the anticonvulsant activities in the maximal electroshock seizure (MES) test and pentylenetetrazol induced seizure(PTZ) test, including the neurotoxicity. The most potent compound in the MES test was (S) N-Cbz-$\alpha$-amino-N-methylglutarimide($ED_{50}$=36.3 mg/kg, PI=1.7). This compound was also most potent in the PTZ test ($ED_{50}$=12.5 mg/kg, PI=5.0). The order of anticonvulsant activities against the MES test as evaluated form $ED_{50}$ values for (R) series was N-methyl > N-H > N-ethyl > N-allyl ; for the (S) series N-methyl > N-H > N-ethyl > N-alkyl > N-isobutyl compound. Against the PTZ tests, the order of anticonvulsant activities showed similar pattern ; for the (R) series, N-methyl > N-H > N-ethyl > N-allyl ; for the (S) series N-methyl > N-H > N-ethyl > N-allyl > N-isobutyl compound. From the above results, N-substituted alkyl groups were though to play an important role for the anticonvulsant activities of N-Cbz-$\alpha$-amino-N-alkylgutarimides.

The reaction of epi-androsterone with cyanoacetyl hydrazine (2) gave the hydrazone derivative 3. The reactivity of 3 towards chemical reagents was studied to give pyridine, thiazole and thiophene derivatives.

Different 2-(8,12 dimethyl-5-oxa-7(E), 11-tridecadienyl)-alkyl phenyl ethers, their mono oxirane and thirane derivatives were synthesized and tested on Culex pipiens quinquefasciatus Say for their juvenile hormone activity.

6-(1-azidoalkyl)-DMNQ derivatives compared to 2-(1-azidoalkyl)-DMNQ isomers, exhibited higher cytotoxic activity against L1210 mouse leukemia cells and stronger inhibition of DNA topoisomerase-I (TOPO-I), suggesting involvement of steric hindrance. However, similar antitumor activity against mice bearing S-180 cell was shown by 2-an 6-(1-azidoalkyl)-DMNQ derivatives.

The biologically active peptidoglycan was purified form the alkali fraction of the fruiting bodies of Ganoderma lucidum and the composition of the peptidoglycan was investigated by conventional analyses. The alkali-extracted peptidoglycan showed differences in chemical compositions from the water-extracted. The alkali-extracted peptidoglycan contained 6.9% protein and 75.9% carbohydrates composed mainly of $\beta$-glucose, mannose, and $\alpha$-glucose. The molecular weight range of the peptidoglycan was determined as 2,000 kDa-17 kDa. The peptidoglycan is considered to be a hybrid molecule of polysaccaride chains covalently bound as a side chain to the polypeptide core.

We have been screening anti-HIV integrase compounds from Korean medicinal plants by using an in vitro assay system which is mainly composed of recombinant human immunodeficency virus type 1 integrase and radiolabeled oligonucleotides. From the above screening, the aqueous methanolic extract of the roots of Agastache rugosa exhibited a significant activity. Bioactivity-guided chromatographic fractionation of the methanolic extract resulted in the isolation of rosmarinic acid. The structure of the compound was determined by spectroscopic data and by the comparison with the reported values. The $IC_{50}$ of the rosmarinic acid was approximately $10{\mu}g/ml$ against HIV integrase.

cis-Annonacin (1) and the mixture of (2,4)-cis-and trans-isoannonacins (2 and 3), three known mono-tetrahydrofuran annonaceous acetogenins, have been isolated form the seeds of Annona cherimolia by the use of the brine shrimp lethality test (BST) for bioactivity directed fractionation. Their structures were elucidated based on spectroscopic and chemical methods. 1 showed potent cytotoxicities in the brine shrimp lethality test (BST) and among six human solid tumor cell lines with notable selectivity for the pancreatic cell line (PaCa-2) at about 1,000 times the potency of adriamycin. The mixture of 2 and 3 is over 10,000 times cytotoxic as adriamycin in the pancreatic cell line (PaCa-2). All of the compounds are about 10 to 100 times as cytotoxic as adriamycin in the prostate cell line (PC-3).