Design, synthesis, and effects of novel phenylpyrimidines as glucagon receptor antagonists.

The hormone glucagon increases blood glucose levels through increasing hepatic glucose output. In diabetic patients, dysregulation of glucagon secretion contributes to hyperglycemia. Thus, the inhibition of glucagon receptor is one target for the treatment of hyperglycemia in type 2 diabetes. Here we designed and synthesized a series of small molecules based on phenylpyrimidine. Of these, the compound (R)-7a most significantly decreased the glucagon-induced cAMP production and glucagon-induced glucose production during in vitro and in vivo assays. In addition, (R)-7a showed good efficacy in glucagon challenge tests and lowered blood glucose levels in diabetic db/db mice. Our results suggest that the compound (R)-7a could be a potential glucose-lowering agent for treating type 2 diabetes.

Anti-platelet and anti-thrombotic effect of a traditional herbal medicine Kyung-Ok-Ko.

ETHNOPHARMACOLOGICAL RELEVANCE: Kyung-Ok-Ko (KOK), a traditional herbal prescription, contains six main ingredients; Rehmannia glutinosa var. purpurae, Lycium chinense, Aquillaria agallocha, Poria cocos, Panax ginseng, and honey. KOK has been widely taken as a traditional oriental medicine for improving blood circulation or age-related symptoms, such as dementia and stroke. However, the effect of KOK on platelet activity has not been clarified. MATERIALS AND METHODS: To evaluate the effect of KOK on platelet function, we evaluated its effect on functional markers of platelet activation such as aggregation and shape change. As a mechanism study for the effect of KOK, we examined its effect on granule secretion, intracellular Ca(2+) increase, and PLCγ and Akt activation. To investigate the effect of orally administered KOK (0.5, 1, 2 g/kg), we examined its ex vivo effect on platelet aggregation in rat, and its in vivo anti-thrombotic effect in mice thromboembolism model. Furthermore, the effect of KOK on bleeding time was examined to estimate its potential side effect. RESULTS: KOK (0.3, 1, 3, 10 mg/ml) inhibited collagen-induced platelet aggregation and shape change in rat platelets in a concentration-dependent manner. The mechanism for the anti-platelet effect of KOK seems to involve the inhibition of ATP release, intracellular Ca(2+) elevation, and the phosphorylation of PLCγ and Akt. In rat ex vivo study, KOK (2 g/kg, p.o. for 1 day, and 0.5, 1, 2 g/kg, p.o. for 7 days) also had significant inhibitory effects on collagen-induced platelet aggregation. In addition, KOK showed a significant protective effect against thrombosis attack in mice. The prolongation of bleeding time by KOK was much less than that by ASA, suggesting a beneficial potential of KOK than ASA in view of side effect. CONCLUSIONS: These findings suggest that KOK elicits remarkable anti-platelet and anti-thrombotic effects with less side effect of bleeding, and therefore, it may have a therapeutic potential for the prevention of platelet-associated cardiovascular diseases.

In vivo absorption and disposition of α-cedrene, a sesquiterpene constituent of cedarwood oil, in female and male rats.

This study aimed to evaluate the potential of α-cedrene as a new anti-obesity drug by characterizing absorption, metabolism and pharmacokinetics in rats. α-Cedrene was administered intravenously (10 and 20 mg/kg) and orally (50 and 100 mg/kg) to female and male Sprague-Dawley rats. Blood, tissues, urine, and feces were collected at predetermined times. α-Cedrene concentrations were determined by a validated gas chromatography-tandem mass spectrometry (GC-MS/MS). A gas chromatography-mass selective detection (GC-MSD) method was used to identify the major metabolite. After i.v. injection, α-cedrene exhibited a rapid clearance (98.4-120.3 ml/min/kg), a large distribution volume (35.9-56.5 l/kg), and a relatively long half-life (4.0-6.4 h). Upon oral administration, it was slowly absorbed (Tmax = 4.4 h) with bioavailability of 48.7-84.8%. No gender differences were found in its pharmacokinetics. Upon oral administration, α-cedrene was highly distributed to tissues, with the tissue-to-plasma partition coefficients (Kp) far greater than unity for all tissues. In particular, its distribution to lipid was notably high (Kp = 132.0) compared to other tissues. A mono-hydroxylated metabolite was identified as a preliminary metabolite in rat plasma. These results suggest that α-cedrene has the favorable pharmacokinetic characteristics to be further tested as an anti-obesity drug in clinical studies.

GC-MS/MS method for the quantification of α-cedrene in rat plasma and its pharmacokinetic application.

α-Cedrene is a pharmacologically active ingredient isolated from the essential oil of cedar. A selective and sensitive GC-MS/MS method was developed for the quantification of α-cedrene in rat plasma for the first time. α-Cedrene was extracted from rat plasma using ethyl acetate at neutral pH. The analytes were determined in selective reaction monitoring mode using MS/MS: m/z 204.3→119.0 for α-cedrene and m/z 146.0→111.0 for 1,4-dichlorobenzene (internal standard). The standard curve was linear (r(2) ≥ 0.995) over the concentration ranges of 5-800 ng/mL. The lower limit of quantification was 5 ng/mL using 50 µL of rat plasma. The coefficient of variation and relative error for intra- and interassays at four quality control levels were 3.1-13.9% and -4.0-2.6%, respectively. The stability of processing (freeze-thaw, long-term storage at -80°C, and short-term storage at room temperature) and chromatography (reinjection) was shown to be of insignificant effect. The present method was applied successfully to the pharmacokinetic study of α-cedrene after its intravenous (10 mg/kg) and oral (25 mg/kg) administration in male Sprague-Dawley rats.

Characterization of a Novel Monoclonal Antibody (27H2) Recognizing Human CD34 Class III Epitope.

BACKGROUND: Monoclonal antibodies (mAbs) recognizing Class III epitope of CD34 are essential for flow cytometric diagnosis of leukemia. METHODS: 27H2 mAb was developed from a mouse alternatively immunized with human acute leukemia cell lines, KG1 and Molm-1. Using flow cytometric analysis of various leukemic cell lines and peripheral blood, immunohistochemical study of frozen tonsil, we characterized 27H2 mAb. Antigen immunoprecipitated with 27H2 mAb immunobloted with anti-CD34 mAb. A case of bone marrow sample of acute lymphoblastic leukemia (ALL) patient was obtained at CBNU Hospital. For epitope identification enzyme treatment with neuraminidase and O-sialoglycoprotein endopeptidase (OSGE) and blocking assay with known classIII mAb (HPCA-2) were done. RESULTS: Only KG1 and Molm-1 revealed positive immunoreactivity. Immunohistochemical staining disclosed strong membranous immunoreactivity on high endothelial venules. Antigen immunoprecipitated by 27H2 mAb showed approximately 100 kDa sized band immunoblotted with anti-CD34 under non-reducing conditions. Epitope recognized by 27H2 mAb disclosed resistancy to both neuraminidase and OSGE treatment and completely blocked with known class III mAb preincubation. CD34 positive leukemic cells in BM of pre B cell ALL patient detected by FITC-conjugated 27H2 and HPCA-2 were identified with similar sensitivity. CONCLUSION: A novel murine mAb recognizing class III epitope of human CD34 with high affinity, which is useful for flow cytometric diagnosis of leukemia, was developed.

Adult stem cell-like tubular cells reside in the corticomedullary junction of the kidney.

The existence of adult renal stem cells has long been suspected because the kidney is capable of regeneration in response to injury, such as acute tubular necrosis (ATN), but their location, or niche, has not been fully defined yet. The aim of this study was to identify the niche of adult renal stem cells responsible for the tubular regeneration. The location of label-retaining cells (LRCs) was studied in adult mouse kidneys after administration of a pulse of bromodeoxyuridine (BrdU) during embryonic period. To study regional participation in renal tubular regeneration, the expression of the proliferation marker Ki-67 was examined after induction of unilateral ATN in mouse kidneys. Regional colony-forming capacity was examined using cultured cells derived from normal mouse and human kidneys and their multipotency was examined in human kidneys. LRCs in adult mouse kidneys were mostly tubular epithelial cells and concentrated constantly in the outer stripe of the corticomedullary junction (CMJ). In the ATN model, Ki-67 positive cells were concentrated in the tubular epithelial cells of the outer stripe, not only in the ATN kidneys but also in the contralateral non-ATN kidneys. High colony-forming capacity was noted in the CMJ of mouse and human kidneys. Cultured cells derived from a single human CMJ cell revealed multipotency, differentiating not only into tubular cells but also into glomerular podocytes. These results demonstrate that the CMJ of the kidney contains label-retaining, renal-repairing, highly colony-forming multipotent stem cell-like tubular cells, suggesting the CMJ as the niche of adult renal stem cells.

eIF-4E expression is associated with histopathologic grades in cervical neoplasia.

Translation initiation factor eIF-4E (eukaryotic initiation factor 4E) is a 25 kd messenger RNA cap-binding phosphoprotein and is involved in the initiation of protein synthesis. The expression is known to be elevated in several carcinomas as compared with normal tissues and benign lesions. In the present study, we undertook to determine whether eIF-4E expression is associated with progression in cervical neoplasia. eIF-4E expression was evaluated by immunohistochemistry in 88 formalin-fixed, paraffin-embedded cervical tissues; 10 normal cervical specimens; 19 low-grade cervical intraepithelial neoplasias (CINs); 19 high-grade CINs; and 40 invasive squamous cell carcinomas (ISCCs). In addition, eIF-4E expression was evaluated at the RNA level in fresh frozen cervical carcinoma tissues by real-time quantitative reverse transcriptase polymerase chain reaction. Immunohistochemical staining showed that eIF-4E expression was undetectable in most normal cervical squamous epithelial tissues (90%), but variable staining was observed in the basal layer of all normal endocervical glands. eIF-4E expression, which was mainly observed as cytoplasmic staining, gradually increased in accordance with histopathologic grade in the order low-grade CIN < high-grade CIN < ISCC (P < .001) and, in particular, was strongly detected in all ISCC cases. Furthermore, real-time quantitative reverse transcriptase polymerase chain reaction revealed that eIF-4E expression in tumor was significantly enhanced versus normal cervical tissues (P = .037). These results suggest that eIF-4E may play a significant role in tumor progression of cervical neoplasia and may represent useful markers for malignant transformation of cervical squamous cells.