Isolation and characterization of two new alkaloids, norpandamarilactonine-A and -B, from Pandanus amaryllifolius by spectroscopic and synthetic methods

Two new alkaloids, norpandamarilactonine-A (1) and -B (2), which have a pyrrolidinyl-alpha,beta-unsaturated gamma-lactone moiety as in the known pandamarilactonine alkaloids, were isolated from the leaves of Pandanus amaryllifolius. Their structures were determined by spectroscopic analysis and total synthesis.     

The Value of Ultrasound-Guided Fine-Needle Aspiration Cytology for Thyroid Nodules: An Assessment of Its Diagnostic Potential and Pitfalls

This study was conducted to assess the diagnostic potential and pitfalls of performing fine-needle aspiration cytology (FNAC) for thyroid nodules. We retrospectively analyzed 1012 aspirated samples obtained from 806 thyroid nodules by the ultrasound (US)-guided method. Of these 806 nodules, 226 (31%) had been surgically treated, 152 (67%) of which were histologically diagnosed as malignant. The rate of sufficient aspirate was 82%, being lower in nodules with a diameter of less than 5 mm (73%, P = 0.10); either calcified (77%, P = 0.043) or benign (72%, P = 0.0002). The accuracy of FNAC was 75%, the rate of indeterminate diagnosis was 16%, the false negative rate was 13%, and the positive malignancy rate was 99%. The rate of indeterminate diagnosis was higher in adenomatous goiter, follicular carcinoma, and malignant lymphoma, at P = 0.015, P = 0.0008, and P = 0.035, respectively. The accuracy was lower in follicular carcinoma and malignant lymphoma (both at P = 0.013). Sufficient aspirate was finally obtained from 701 (87%) of the 806 nodules by repeated aspiration. Of 152 malignant nodules, 28 (18%) were diagnosed after two or more aspirations, and the accuracy was improved to 81% by repeating the procedure. These findings indicated that repeated aspiration may be a simple and effective method of improving the diagnostic potential of FNAC. Received: November 1, 1999 / Accepted: September 26, 2000     

Effects of a p38 mitogen-activated protein kinase inhibitor as an additive to university of wisconsin solution on reperfusion injury in liver transplantation

BACKGROUND: Activation of p38 mitogen-activated protein kinase (MAPK) plays an important role in the development of ischemia/reperfusion injury in nonhepatic organs, such as the heart. However, the role of p38 MAPK activation in the liver is unclear. We examined the effects of FR167653, a novel p38 MAPK inhibitor, as an additive to University of Wisconsin (UW) solution in rat liver transplantation. METHODS: Rat orthotopic liver transplantation was performed after 30 hr of cold storage using UW solution with or without FR167653. Ten-day survival rates, serum alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) levels, liver tissue blood flow, histological findings, and activities of p38 MAPK and p46/p54 c-Jun N-terminal kinase (JNK) in liver grafts were evaluated. RESULTS: The addition of FR167653 significantly increased animal survival rates. FR167653 significantly suppressed serum ALT and LDH levels and improved liver tissue blood flow after transplantation. FR167653 also ameliorated histological damage to the liver graft. Neither p38 MAPK nor p46/p54 JNKs was activated during cold storage, whereas both were markedly activated within 30 min of reperfusion and remained activated until 60 min after reperfusion. FR167653 inhibited the activation of p38 MAPK both 30 and 60 min after reperfusion, but it did not affect the activation of p46/p54 JNKs. CONCLUSIONS: The addition of FR167653 to UW solution improved liver graft viability and animal survival rates associated with the inhibition of p38 MAPK activation. These results suggest that inhibiting the activation of p38 MAPK may attenuate ischemia/reperfusion injury in liver transplantation.     

A simple method for the analysis of root canal preparation

The purpose of this article is to present a simple and easy method for in vitro analysis of root canal instrumentation that permits one to observe and measure the diameter of a root before and after instrumentation, using the teeth themselves as control.     

Ketoacidosis accompanied by epileptic seizures in a patient with diabetes mellitus and mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS)

We herein report a rare case of MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) and diabetes mellitus with ketoacidosis. An 18-year-old female patient was diagnosed to have diabetes mellitus and insulin therapy was thereafter initiated. At 26 years of age, she was hospitalized for diabetic ketoacidosis, soon followed by a loss of consciousness, left-sided dysmetria, and ataxic speech. MELAS was diagnosed because of the presence of ragged red fibers in a muscle biopsy. At 33 years of age, she was admitted to our hospital because of ketoacidosis and partial status epilepticus. A blood gas examination revealed as follows; arterial pH, 6.88; bicarbonate, 2.1 mmol/l; base excess - 29.8 mmol/l. The serum level of glucose had also increased to 30 mmol/l. The serum levels of lactate and B-hydroxybutyrate were elevated to 11.4 mmol/l and 1,990 micromol/l, respectively. Ketoacidosis improved by fluid replacement and continuous intravenous insulin infusion. A brain MRI demonstrated hyperintensity areas on FLAIR images in the bilateral temporal lobes and the cerebellum. A proton MRS demonstrated the abnormal lactate accumulation in the bilateral temporal and occipital lobes. Since epileptic seizures are rare in patients with diabetic ketoacidosis, such seizures may indicate the existence of MELAS syndrome.     

Opioid receptor agonistic characteristics of mitragynine pseudoindoxyl in comparison with mitragynine derived from Thai medicinal plant Mitragyna speciosa.

We have previously elucidated the opiate-like action of mitragynine, an active principle isolated from the Thai medicinal plant Mitragyna speciosa. In the present study, effects of the related compound, mitragynine pseudoindoxyl on electrically stimulated contraction in guinea pig ileum and mouse vas deferens, and on its binding affinity in the guinea pig brain membranes were studied. Mitragynine pseudoindoxyl inhibited the electrically stimulated ileum and mouse vas deferens contractions in a concentration-dependent manner. In the ileum, the effective concentration is in an nM order, being nearly equivalent to reported concentrations of the micro-opioid receptor agonist [D-Ala2, Met-Phe4, Gly-ol5] enkephalin (DAMGO), and is 100- and 20-fold smaller than those of mitragynine and morphine, respectively. In the vas deferens, it is 35-fold smaller than that of morphine. The inhibitory action of mitragynine pseudoindoxyl in the ileum was antagonized by the non-selective opioid receptor antagonist naloxone and the micro-receptor antagonist naloxonazine. It was also antagonized by the delta-receptor antagonist naltrindole in the vas deferens. Mitragynine pseudoindoxyl showed a similar binding affinity to DAMGO and naltrindole at micro- and delta-receptors, respectively. However, the affinity at kappa-receptors was negligible. The present study demonstrates that mitragynine pseudoindoxyl, a novel alkaloid structurally different from other opioid agonists, acts on opioid receptors, leading to a potent inhibition of electrically stimulated contraction in the ileum through the micro-receptors and in mouse vas deferens through delta-receptors.     

Mode of action of a new indolocarbazole anticancer agent, J-107088, targeting topoisomerase I.

J-107088 [6-N-(1-hydroxymethyl-2-hydroxy)ethylamino-12,13-dihydro-2,10-dihydroxy- 13-(beta-D-glucopyranosyl)-5H-indolo[2,3-a]-pyrrolo[3,4-c]-carb azo le-5,7(6H)-dione] is a new derivative of NB-506, an indolocarbazole antitumor agent. J-107088 induced single-strand DNA cleavage only in the presence of topoisomerase I (top1) more effectively than NB-506 or camptothecin. The preferable sequences of the DNA cleaved by J-107088 were C/T / G as in the case of NB-506. This base-preference of J-107088 in top1-mediated cleavage was different from that of camptothecin, which was T / G/A. top1 poisons stabilize the complex between DNA and top1 (cleavable complex). This cleavable complex is released on addition of a high concentration of monovalent cation or removal of top1 poisons. The complex induced by J-107088 was quite stable; it was scarcely released on the addition of NaCl or dilution of J-107088, contrary to the case with camptothecin and NB-506. J-107088-inducing complexes were also stable in cultured cells, when the compound was added to the culture medium. These unique in vitro activities of J-107088 on top1 that differed from those of camptothecin and NB-506 may be relevant to its more potent in vivo antitumor efficacy in a human tumor xenographted nude mouse model.     

Detection of apoptosis in acute promyelocytic leukemia cells in vivo during differentiation-induction with all-trans retinoic acid in combination with chemotherapy.

In two patients with acute promyelocytic leukemia (APL) treated with all-trans retinoic acid (ATRA) in combination with chemotherapy, we demonstrated that cells with apoptotic morphology were recognized in a small fraction of whole blood cells (0.2-0.4%) at the regression phase of leukocytosis with mostly maturing aberrant granulocytes of APL clone origin. Moreover, in a light-density cell fraction ( < 1.077) of peripheral blood or marrow cells obtained from three patients, DNA fragmentation was detected by agarose gel electrophoresis temporarily. These findings may suggest that, during the treatment with ATRA, a small fraction of APL cells maturing toward the stage of terminal differentiation underwent apoptosis in vivo, which might be enriched by the combination of chemotherapy to ATRA administration.     

Chemical studies on the analgesic indole alkaloids from the traditional medicine (Mitragyna speciosa) used for opium substitute

The leaves of a tropical plant, Mitragyna speciosa Korth. (Rubiaceae), have been traditionally used as a substitute for opium. By phytochemical studies on the constituents of the plant growing in Thailand as well as in Malaysia, several 9-methoxy-Corynanthe-type monoterpenoid indole alkaloids including new natural products were isolated. The structures of these new compounds were elucidated by the modern spectroscopic methods and/or chiral-total syntheses. The chiral total synthesis of (-)-mitragynine, a major component of this plant, was achieved. Potent opioid agonistic properties of mitragynine, which acts on mu- and delta-opioid subtype receptors, and of mitragynine pseudoindoxyl, whose analgesic activity is more potent than that of morphine, were clarified in in vitro experiments. The essential structural features in mitragynine for revealing the analgesic activity were elucidated by pharmacological evaluation of the natural and synthetic mitragynine derivatives.