Total synthesis of (-)-neplanocin a by using lithium thiolate-initiated Michael-aldol tandem cyclization reaction

(-)-Neplanocin A (1), S-adenosylhomocystein hydrolase inhibitor, was synthesized. The characteristic of this synthesis is a stereoselective construction of five-membered ring of neplanocin A by intramolecular aldol reaction of the lithium enolate that was generated by conjugate addition of lithium thiolate. TBS-protected chiral omega-oxo-alpha,beta-unsaturated ester 16, which was prepared from D-mannitol, was treated with 1.2 equiv of lithium benzylthiolate in THF at -20 degrees C to give three separable cyclization products in good yields and stereoselectivity. After conversions of protective groups, the benzylsulfanyl part of 21 was removed by oxidation to sulfoxide and subsequent thermal elimination to give the requisite double bond. Through the functional group transformations of 30, total synthesis of (-)-neplanocin A (1) was accomplished.

Difference in degree of mucosal atrophy between elevated and depressed types of gastric epithelial tumors

BACKGROUND

The significance of atrophy in the background mucosa and Helicobacter pylori infection in the morphogenesis of gastric epithelial tumors has not yet been investigated.

METHODS

The degree of mucosal atrophy, as determined by a histological analysis and the serum pepsinogen (PG) levels, and H. pylori status were investigated in patients with elevated adenoma (EA group; n = 40), elevated early cancer of intestinal type (ECI group; n = 30), depressed early cancer of intestinal type (DCI group; n = 37) and depressed early cancer of diffuse type (DCD group; n = 33), and the findings were then compared to those in 91 controls.

RESULTS

At all sites of the stomach, the histologic score of atrophy was higher in the EA group and in the ECI group than in the controls. In the DCI group, the histologic score of atrophy in the antrum was higher than in the controls, but no such difference in the score was found in the DCD group. The PG I/II ratios in the EA, ECI and DCI groups were significantly lower than in the controls, and the value was also different between the ECI and DCI groups. While H. pylori prevalence was higher in all groups than in the controls, a logistic regression analysis which included the grade of atrophy as a determinant revealed the infection to be an independent associated factor for the DCD group.

CONCLUSIONS

The difference in the background mucosal atrophy seems to contribute to different macroscopic types in gastric epithelial tumors. This seems to be the case especially for cancer of intestinal type.

Electronic and steric control in regioselective addition reactions of organolithium reagents with enaldimines

A reaction mode of imines derived from naphthalene-1-carbaldehyde and acyclic alpha,beta-unsaturated aldehydes with organolitium reagents was dependent on the characteristic nature of a substituent on the imine nitrogen atom. An imine having an electron-withdrawing aryl group on the nitrogen atom behaves as a 1,2-directing imine toward organolithium reagents. In contrast, an imine bearing an alkyl or a bulky aryl group favors 1,4-addition of organolithium reagents. Electronic and steric tuning of a substituent on the imine nitrogen atom for a reaction mode was rationalized on the basis of molecular orbital calculations.

YM-40461 improves airway clearance in guinea pigs with induced subacute bronchitis

The effects of the surfactant secretagogue YM-40461 on the mucociliary transport (MCT) velocity were examined in guinea pigs with induced bronchitis. Guinea pigs were exposed to SO2 gas (900 ppm, 3 h/d) for 5 d. MCT velocity was measured by the movement of a 30% gelatin solution containing Evans blue dye placed on the tracheal mucosal surface. Repeated doses of YM-40461 improved the MCT guinea pigs with bronchitis within 5 d after the completion of SO2 exposure, with an ED50 value of 3.1 mg/kg p.o. At a dose of 10 mg/kg p.o., YM-40461 restored MCT to the control level (98.0% recovery). Ambroxol, bromhexine and salbutamol also improved MCT, but were far less effective than YM-40461. Airway fluid collected from bronchitic animals revealed increased disaturated phosphatidylcholine (DSPC, a major component of surfactants)-to-protein ratio and decreased surface tension produced by YM-40461 treatment (10 mg/kg). These results suggest that YM-40461 ameliorates MCT dysfunction in animals with SO2 gas-induced bronchitis by increasing the DSPC-to-protein ratio in the airway.

Controlling factors in chiral bisoxazoline-catalyzed asymmetric lithium ester enolate-imine condensation producing a beta-lactam

A catalytic amount of external chiral bisoxazoline ligand 3a bearing an isopropyl group as a stereocontrolling group catalyzed a reaction of a lithium ester enolate 4b, generated from 3-pentyl 2-methylpropionate, with benzaldehyde anisidine-imine 5 to afford corresponding beta-lactam 6 in higher 70% ee than that obtained by the reaction using a stoichiometric amount of the ligand. A bulkier ligand 3d bearing a phenyl group gave 81% and 6% ees in stoichiometric and catalytic reactions, respectively. Examination of the varying factors suggested the involvement of mixed aggregates as a reactive species. A working model is presented for prediction of the sense of asymmetric induction.

YM-40461, a potent surfactant secretagogue, improves mucociliary clearance in SO2-exposed guinea pigs

The effects of the new pulmonary surfactant secretagogue YM-40461, 1-(2-dimethylaminoethyl)-1-(3,4,5-trimethoxyphenyl) urea, on tracheal mucociliary transport (MCT) were assessed using guinea pigs with acute bronchitis. Acute bronchitis was induced by SO2 gas exposure (400 ppm for 3 h). MCT velocity was measured by means of the dye gelatin technique. YM-40461 at doses of 1-10 mg/kg, p.o. induced recovery of MCT function, with an ED50 value of 2.4 mg/kg. Maximal recovery (78.0+/-12.5%) was observed 2 h in the animals treated with 10 mg/kg of YM-40461. Ambroxol and bromhexine showed less effect on the MCT dysfunction than YM-40461. An artificial surfactant (Surfacten) also aided recovery. YM-40461 at a dose of 10 mg/kg, p.o. significantly improved surfactant production without affecting mucus secretion. These results show that YM-40461 ameliorates MCT dysfunction caused by SO2 exposure by activation of pulmonary surfactant secretion.

Podophyllotoxin aza-analogue, a novel DNA topoisomerase II inhibitor

The pendant E-ring moiety of the podophyllotoxin aza-analogue 1 that is a potent inhibitor of microtubule assembly was modified in order to acquire inhibitory activity of DNA topoisomerase II. The monophenolic analogue 2 did not exhibit human topoisomerase II inhibition, while the ortho-quinone 3 that was obtained by oxidation of 2 inhibited its catalytic activity (decatenation) in a dose-dependent manner and stimulated double strand DNA breaks in supercoiled circular plasmid DNA, resulting in the production of linear DNA. These results showed that the topoisomerase II inhibition of the ortho-quinone 3 is due to stabilization of the topoisomerase II-DNA covalent binary complex. On the other hand, the ortho-quinone 3 did not inhibit the relaxation process of supercoiled DNA by topoisomerase I at concentrations up to 400 microM, nor was intercalation observed in unwinding measurements of 3. Therefore, the ortho-quinone 3 was shown to be a novel nonintercalative topoisomerase II specific inhibitor that stabilizes the cleavable complex. The present results suggest that the 4'-free hydroxyl group on the E-ring and the sugar moiety on the C-ring are not a prerequisite for topoisomerase II inhibition by podophyllotoxin derivatives.

Protein synthesis is a required process for the optic lobe circadian clock in the cricket Gryllus bimaculatus

The effects of a translation inhibitor, cycloheximide (CHX), on the circadian neuronal activity rhythm of the optic lamina-medulla compound eye complex cultured in vitro were investigated in the cricket Gryllus bimaculatus. When the complex was treated with 10(-5) M CHX for 6 h, the rhythm exhibited a marked phase shift. The magnitude and direction of the phase shift were dependent on the phase at which the complex was treated with CHX; phase delays occurred during the late subjective day to early subjective night, whereas phase advances occurred around the late subjective night. Continuous application of CHX abolished circadian rhythms of both the spontaneous neuronal activity and the visually evoked response. However, it abolished neither the spontaneous activity nor the visually evoked response. As washed with fresh medium after CHX treatment, the rhythm soon reappeared and the subsequent phase was clearly correlated to the termination time of the treatment. These results suggest that protein synthesis is also involved in the cricket optic lobe circadian clock, and that the clock-related protein synthesis may be active during the late subjective day to subjective night.

Helicobacter pylori and mucosal atrophy in patients with gastric cancer: a special study regarding the methods for detecting Helicobacter pylori

We assessed the sensitivities of several methods for detecting Helicobacter pylori (culture, histology, rapid urease test, and serology), and evaluated the H. pylori positivity considering the degree of atrophy in the background mucosa in 202 gastric cancer patients and 101 controls. The positivity of H. pylori determined by culture (81%) was significantly higher than that determined by serology (62%) in gastric cancer patients (P < 0.001). The positivities of H. pylori determined by biopsy and/or serology in intestinal (84%) and diffuse (95%) types of gastric cancer were higher than that observed in controls (54%) (P < 0.001). Intestinal-type gastric cancer tended to occur in the atrophic mucosa, in which H. pylori positivity was not different from that in controls after adjusting for the degree of atrophy, whereas diffuse-type gastric cancer was observed more often in the nonatrophic mucosa, in which H. pylori positivity was higher than that in controls even after adjusting for the degree of atrophy.

Transient splenomegaly in acute pancreatitis

Serial changes in splenic volume of 25 patients (18 men and seven women; 53.4 +/- 20.8 years old, range 25-83) with acute pancreatitis who underwent CT examinations were retrospectively studied. Abdominal CT was performed within 3 days after the onset and there was at least one follow-up CT examination after this time. The percentage changes of splenic volume in the first (4-30 days) and second (31-100 days) follow-up CT were calculated. Splenic volume increased in the first follow-up CT (mean +/- SD: 197.8 +/- 121.0 cm3) compared with the initial CT (124.8 +/- 70.0; p < 0.0001), and then decreased in the second follow-up CT (179.7 +/- 100.7; p < 0.002). The average splenic volume increased 65.5 +/- 88.7% (range -10.4-377.4%) between the initial and first follow-up CT examinations. Five of 25 cases (20%) in whom size of spleen increased more than twice had severe acute pancreatitis (p < 0.05), complicated pseudocyst requiring surgical drainage (p < 0.05), pleural effusion (p < 0.01), splenic vein thrombosis or compression (p < 0.05) and longer hospital stay (p < 0.02) compared with patients with a smaller increase in splenic volume. In conclusion, transient splenomegaly was commonly seen in acute pancreatitis, especially in severe or complicated cases. Congestive splenomegaly caused by obstruction or stenosis of the splenic vein and non-specified acute splenitis were suspected of contributing to the transient splenomegaly.

timrit Lengthens circadian period in a temperature-dependent manner through suppression of PERIOD protein cycling and nuclear localization

A fundamental feature of circadian clocks is temperature compensation of period. The free-running period of ritsu (timrit) (a novel allele of timeless [tim]) mutants is drastically lengthened in a temperature-dependent manner. PER and TIM protein levels become lower in timrit mutants as temperature becomes higher. This mutation reduces per mRNA but not tim mRNA abundance. PER constitutively driven by the rhodopsin1 promoter is lowered in rit mutants, indicating that timrit mainly affects the per feedback loop at a posttranscriptional level. An excess of per+ gene dosage can ameliorate all rit phenotypes, including the weak nuclear localization of PER, suggesting that timrit affects circadian rhythms by reducing PER abundance and its subsequent transportation into nuclei as temperature increases.

A new, simple method for measuring mucociliary clearance in guinea-pigs

Airway mucociliary transport (MCT), which continuously removes inhaled particles and cellular debris from deep in the lung, is impaired in a number of diseases such as bronchitis and asthma. In order to determine the effects of candidate drugs on MCT function in the airway, a new in situ method to measure MCT function was established. MCT function is represented by the distance a gelatin solution containing Evans blue as a marker moves after injection into the trachea. The basal rate of dye transport in non-treated guinea-pigs was 4.4+/-0.2 mm/min. The beta2-adrenoceptor agonist salbutamol (2, 6, 10, 20 mg/kg, po), dose-dependently accelerated the basal MCT rate. However, its effect was completely inhibited by pretreatment with the non-selective beta -adrenoceptor antagonist, propranolol (1 mg/kg, iv). MCT function in guinea-pigs was significantly attenuated to 2.6+/-0.3 mm/min by SO2 gas exposure. Salbutamol failed to prevent MCT dysfunction in SO2-exposed animals at doses previously shown to accelerate basal MCT rate. This simple method is useful for estimating MCT function in several airway disease models and for examining new drugs designed to improve MCT function in airway diseases.

2-(3-Pyridyl)thiazolidine-4-carboxamide derivatives. III.) Synthesis of metabolites and metabolism of 2-(3-pyridyl)thiazolidine-4-carboxamides YM461 and YM264 as platelet-activating factor (PAF) receptor antagonists

The metabolism of 2-(3-pyridyl)thiazolidine-4-carboxamides YM461 and YM264 was investigated, and their metabolites were compared with separately synthesized materials by measuring 1H-NMR spectra, mass spectra, and HPLC retention times, and evaluated for platelet activating factor (PAF) antagonistic activity. YM461 was metabolized by two different metabolic pathways (cleavage of the thiazolidine ring and oxidation of the benzyl position), whereas YM264 was metabolized by three metabolic pathways. The minor metabolite M7 from YM264 possessed potent PAF antagonistic activity, as strong as YM264 and this existed as an active metabolite. From pharmacokinetics studies, YM264 was almost completely absorbed from the gastrointestinal tract, but readily metabolized in rats. In dogs, pharmacokinetic parameters of YM264 were significantly improved compared to those in rats, and YM264 tended to show better pharmacokinetics than YM461 due to an extension of the half-life period.

2-(3-Pyridyl)thiazolidine-4-carboxamide derivatives. II. Structure-activity relationships and active configuration of 2-(3-pyridyl)thiazolidine-4-carboxamides as platelet-activating factor receptor antagonists

Conversion of the 2-(3-pyridyl)thiazolidine part of 1-(3-phenylpropyl)-4-[2-(3-pyridyl)thiazolidine-4-carbonyl]piperazine (YM461), which is a potent platelet-activating factor (PAF) antagonist, to other rings was performed, and PAF antagonistic activities evaluated. The 2-(3-pyridyl)thiazolidine skeleton, which exists as a mixture of cis and trans diastereomers, played an important role in the potency of PAF antagonism. In this study, new effective skeletons were not uncovered, however, 2-(4-pyridyl)thiazolidine-4-carboxamides (1n and 1z) showed potent PAF antagonistic activities equal to the 3-pyridyl derivatives. From the results obtained for 1a, 1a(S), 1g and 1i, a cis-(2R,4R)-2-(3-pyridyl)thiazolidine-4-carboxamide was assumed to be the active configuration for PAF antagonism.

Light and temperature cooperate to regulate the circadian locomotor rhythm of wild type and period mutants of Drosophila melanogaster

In the wild type (Canton-S) and period mutant flies of Drosophila melanogaster, we examined the effects of light and temperature on the circadian locomotor rhythm. Under light dark cycles, the wild type and per(S) flies were diurnal at 25 degrees C. However, at 30 degrees C, the daytime activity commonly decreased to form a rather nocturnal pattern, and ultradian rhythms of a 2 approximately 4h period were observed more frequently than at 25 degrees C. The change in activity pattern was more clearly observed in per(0) flies, suggesting that these temperature dependent changes in activity pattern are mainly attributable to the system other than the circadian clock. In a 12h 30 degrees C:12h 25 degrees C temperature cycle (HTLT12:12), per(0) flies were active during the thermophase in constant darkness (DD) but during the cryophase in constant light (LL). The results of experiments with per(0);eya flies suggest that the compound eye is the main source of the photic information for this reversal. Wild type and per(0) flies were synchronized to HTLT12:12 both under LL and DD, while per(S) and per(L) flies were synchronized only in LL. This suggests that the circadian clock is entrainable to the temperature cycle, but the entrainability is reduced in the per(S) and per(L) flies to this particular thermoperiod length, and that temperature cycle forces the clock to move in LL, where the rhythm is believed to be stopped at constant temperature.

[The effects of YM26818: 1-(2-dimethylaminoethyl)-1-(3,4,5-trimethoxyphenyl)urea and derivatives on pulmonary surfactant secretion and lung compliance]

To discover a novel compound which has an effect on pulmonary surfactant (PS) secretion, we studied the effects of various compounds on PS secretion by measuring the contents of PS in the bronchoalveolar lavage (BAL) fluid in guinea pigs. In the chemical modification study of ambroxol, which is known as a PS secretagogue, and a compound we discovered from our compounds library, 1-(2-dimethylaminoethyl)-1-(3,4,5-trimethoxyphenyl)urea: YM-26818 (the increasing effect on PS in BALF, 34.7% at 50 mg/kg, i.p.). In the surfactant deficient model induced by BAL in guinea pigs, YM-26818 (5 and 10 mg/kg, p.o.) significantly increased the contents of PS in the BAL fluid compared with that of control animals (5 mg/kg: 60.3 +/- 8.0, 10 mg/kg: 59.4 +/- 4.3% increase). Concomitantly by these effects, the recovery of lung compliance was observed in this model (AUC of lung volume, control: 560 +/- 15, YM-26818 5 mg/kg: 898 +/- 51, YM-2681 10 mg/kg: 956 +/- 11 ml.min). These results may indicate that YM-26818 is useful for the therapy of adult respiratory distress syndrome (ARDS) and obstructive pulmonary diseases.

Effects of 5,7-DHT Injection into the Optic Lobe on the Circadian Locomotor Rhythm in the Cricket, Gryllus bimaculatus

The effect of direct 5,7-dihydroxytryptamine (5,7-DHT) injection into the medulla region of the optic lobe on the locomotor activity was investigated in the adult male cricket, Gryllus bimaculatus. After a 6 hr phase advance of a light-dark cycle, the 5,7-DHT injected animals needed significantly longer time for resynchronization to the new cycle (6.55 +/- 0.62 days) than the control, Ringer's solution injected animals (3.17 +/- 0.15 days; P < 0.001, t-test). Light induced a bout of activity (i.e., masking effect) when light-dark cycle was phase advanced by 6 hr and the duration of the masking effect was significantly longer in 5,7-DHT injected animals. An initial bout of the nocturnal activity was significantly greater in the 5,7-DHT injected animal. Under constant darkness, the freerunning periods of both groups were not significantly different. Under constant light, a significantly higher percentage of 5,7-DHT injected animals showed arrhythmicity compared with the control group. An analysis carried by high-pressure liquid chromatography with electro-chemical detection (HPLC-ECD) revealed that the serotonin content in the optic lobe was significantly reduced to less than 50% in the 5,7-DHT injected animals, even one month after the injection. These results suggest that serotonin plays important roles in the regulation of circadian locomotor rhythms of the cricket mainly by regulating the sensitivity of the photoreceptive system.

Enhancement of tissue-type plasminogen activator-induced thrombolysis and prevention of reocclusion by combination with a humanized anti-glycoprotein IIb/IIIa monoclonal antibody, YM337, in a rhesus monkey model of coronary thrombosis

We examined the effect of a humanized anti-glycoprotein IIb/IIIa monoclonal antibody, YM337, on thrombolysis with tissue-type plasminogen activator in a copper coil-induced coronary thrombosis model in rhesus monkeys. Fifty minutes after the formation of an occlusive thrombus, a test drug was administered by either i.v. bolus injection followed by continuous infusion (YM337, 0.25 mg/kg + 1.5 microg/kg/min) or i.v. bolus injection (aspirin, 17 mg/kg). Sixty minutes after induction of the occlusive thrombus, thrombolysis was initiated with tPA at a total dose of 0.5 mg/kg intravenously administered over 60 min, with 10% given as an initial bolus. The median time to reperfusion was significantly shortened by YM337 [saline, 60 min (n = 5); aspirin, 45 min (n = 5); YM337, 30 min (n = 5)]. The incidence of reocclusion was significantly decreased by YM337 (saline, 4/4; aspirin, 5/5; YM337, 1/5), and the median time to reocclusion was significantly prolonged by YM337 [saline, 30 min (n = 4); aspirin, 30 min (n = 5); YM337, 180 min (n = 5)]. YM337 significantly reduced the thrombus protein content at the end of experiment. ADP-induced platelet aggregation was completely inhibited by YM337. These results suggest that YM337 may be of clinical value as an adjunctive agent in thrombolytic therapy for patients with acute myocardial infarction.

Circadian locomotor rhythms in the cricket, Gryllodes sigillatus. II. Interactions between bilaterally paired circadian pacemakers

The optic lobe is essential for circadian locomotor rhythms in the cricket, Gryllodes sigillatus. We examined potential interactions between the bilaterally paired optic lobes in circadian rhythm generation. When one optic lobe was removed, the free-running period of the locomotor rhythm slightly but significantly lengthened. When exposed to light-dark cycles (LD) with 26 hr period, intact and sham operated animals were clearly entrained to the light cycle, but a large number of animals receiving unilateral optic nerve severance showed rhythm dissociation. In the dissociation, two rhythmic components appeared; one was readily entrained to the given LD and the other free-ran with a period shorter than 24 hr, and activity was expressed only when they were inphase. The period of the free-running component was significantly longer than that of the animals with a single blinded pacemaker kept in LD13:13, suggesting that the pacemaker on the intact side had some influence on the blinded pacemaker even in the dissociated state. The ratio of animals with rhythm dissociation was greater with the lower light intensity of the LD. The results suggest that the bilaterally distributed pacemakers are only weakly coupled to one another but strongly suppress the activity driven by the partner pacemaker during their subjective day. The strong suppression of activity would be advantageous to keep a stable nocturnality for this cricket living indoors.

Circadian locomotor rhythms in the cricket, Gryllodes sigillatus. I. Localization of the pacemaker and the photoreceptor

Circadian locomotor rhythm and its underlying mechanism were investigated in the cricket, Gryllodes sigillatus. Adult male crickets showed a nocturnal locomotor rhythm peaking early in the dark phase of a light to dark cycle. This rhythm persisted under constant darkness (DD) with a free-running period averaging 23.1 +/- 0.3 hr. Although constant bright light made most animals arrhythmic, about 40% of the animals showed free-running rhythms with a period longer than 24 hr under constant dim light condition. On transfer to DD, all arrhythmic animals restored the locomotor rhythm. Bilateral optic nerve severance resulted in free-running of the rhythm even under light-dark cycles. The free-running period of the optic nerve severed animals was significantly longer than sham operated crickets in DD, suggesting that the compound eye plays some role in determining the free-running period. Removal of bilateral lamina-medulla portion of the optic lobe abolished the rhythm under DD. These results demonstrate that the photoreceptor for entrainment is the compound eye and the optic lobe is indispensable for persistence of the rhythm. However, 75% and 54% of the optic lobeless animals showed aberrant rhythms with a period very close to 24 hr under light and temperature cycles, respectively, suggesting that there are neural and/or humoral mechanisms for the aberrant rhythms outside of the optic lobe. Since ocelli removal did not affect the photoperiodically induced rhythm, it is likely that the photoreception for the rhythm is performed through an extraretinal photoreceptor.

2-(3-Pyridyl)thiazolidine-4-carboxamides. 1. Novel orally active antagonists of platelet-activating factor (PAF)

In a search for novel platelet-activating factor (PAF) antagonists, we found that 1-(3-phenylpropyl)-4-[2-(3-pyridyl)thiazolidine-4-carbonyl] piperazine (3x) showed in vitro and in vivo PAF-antagonistic activities. Introduction of functional groups at the benzylic methylene carbon of 3x afforded some compounds with more potent PAF-antagonistic activity than 3x. Among them 1-(3-methyl-3-phenylbutyl)-4-[2-(3-pyridyl) thiazolidine-4-carbonyl]-piperazine fumarate (3al, YM264) was found to be one of the most potent PAF antagonists.

[MR spectroscopy in acute brain infarction: differentiation of infarcted and non-infarcted areas]

Two cases of brain infarction were studied using multivoxel proton MR spectroscopy (MRS). MRS of both cases clearly demonstrated an increased level of lactate and decreased N-acetylaspartate (NAA), resulting in a high lactate/NAA ratio (LNR). Case 1 without thrombolysis therapy revealed that the area where LNR was less than 1.0 did not develop to infarction. This was also confirmed by MRS of case 2, who received an interventional reperfusion 4 hours after onset. In acute stags of brain infarction, on LNR greater than 1.0 on H-MRS may predict the margin of the infarcted region. Elevation of lactate in the non-infarcted cerebral hemisphere has not been reported before, and farther evaluation is necessary.