Convenient synthesis of 4-trifluoromethyl-substituted imidazole derivatives

Mesoionic 4-trifluoroacetyl-1,3-oxazolium-5-olates (1), obtained from the reaction of N-acyl-N-alkylglycines (2) with trifluoroacetic anhydride, react with ammonia to give 4-trifluoromethyl-3,4-dihydroimidazoles (3) in high yields. Dehydration of 3 gives 4-trifluoromethylimidazoles (4) in high yields. The novel ring transformation of 1 into 3 occurs via a regioselective attack of ammonia on the C-2 position of the ring.

Reaction kinetics and modeling of the enzyme-catalyzed production of lactosucrose using beta-fructofuranosidase from Arthrobacter sp. K-1

Lactosucrose synthesis from sucrose and lactose was carried out by using beta-fructofuranosidase from Arthrobacter sp. K-1. The transfructosylation mechanism was found to be of an ordered bi-bi type in which sucrose was bound first to the enzyme and lactosucrose was released last. Hydrolysis side-reaction experiments indicated that the reactions were uncompetitively inhibited by glucose and lactose, while no inhibition by fructose was apparent. The overall reaction rates were formulated. The reaction rate constants, equilibrium constant, and dissociation and Michaelis constants were determined at 35 degrees C and 50 degrees C by fitting the experimental concentration changes with the calculated values by a nonlinear least-square method. The average relative derivation for the concentrations was 9.67%. The kinetic parameters were also calculated for 43 degrees C and 60 degrees C by assuming the Arrhenius law, and the course of reaction was predicted. The obtained reaction rate equations well represented the concentration changes during the experiment at all temperatures.

Suppression of apoptosis in hepatocytes by fructose-modified dendrimers

By immobilizing fructose-modified dendrimers on a polystyrene culture plate, the number of initially adhered hepatocytes on it was increased. Moreover, increasing the number of generations of fructose-modified dendrimer (fructose-dendrimer) increased the number. Urea synthesis per unit area also was increased, corresponding to the increase in the number of initially adhered hepatocytes. This result suggests that the fructose-dendrimers do not cause a decline in cell function. On the other hand, apoptosis of hepatocytes occurs during cultivation, and results in a decrease in the number of adhered cells and a decline in cell function. Fructose-dendrimers were found to suppress apoptosis of hepatocytes. This characteristic is considered to be responsible for the increase in the number of initially adhered hepatocytes without a decline in cell function. Fructose-dendrimers are shown to be very suitable scaffolds for use in a high-performance bioartificial liver support system.

Pharmacokinetic and pharmacodynamic evaluations of a potent analgesic, dihydroetorphine, in hairless rat

To evaluate the pharmacokinetic and pharmacodynamic characteristics of a novel opioid analgesic, dihydroetorphine (DHE), concentrations of DHE and its glucuronide (DG) in plasma and central nervous system (by liquid chromatography-tandem mass spectrometry) and the antinociceptive effect (by tail-immersion test) were measured after intravenous (i.v., 2 microg/kg), intracutaneous (i.c., 2 microg/kg), subcutaneous (s.c., 2 microg/kg), intraperitoneal (i.p., 10 microg/kg), and oral (p.o., 200 microg/kg) administrations in hairless rats. An elimination half-life of plasma DHE concentration was 37.2 min after i.v. injection. Brain DHE concentration reached a maximum within 6 min after i.v. injection, and the concentration ratio in brain to plasma was 5.17. Relative bioavailabilities of DHE to i.v. injection (100%) were 70.8, 79.8, 16.7, and 0.37% after i.c., s.c., i.p., and p.o. administrations, respectively. Area under the plasma concentration-time curve ratios of plasma DG to DHE concentrations after i.v., i.c., s.c., i.p., and p.o. were 1.76, 3.26, 4.74, 14.5, and 290, respectively. Antinociceptive effects appeared rapidly after i.v., i.c., and s.c. administrations but were diminished after i.p. and p.o. administrations, and these effects were closely related to the brain DHE concentrations. DHE was excreted mainly as DG in bile (89.5% of the dose) by 240 min after i.v. injection. Serum protein binding of DHE was 83.4%, which was not influenced by DG. Glucuronidation of DHE was detected in the liver, intestine, and kidney in vitro but was minimal in the skin and brain. In conclusion, DHE was rapidly distributed to the brain in relation to producing the antinociceptive effect, and then it was rapidly metabolized to the pharmacologically inactive DG.

Antimicrobial activity of new coumarin derivatives

A preliminary exploration of coumarin analogs as novel antimicrobial agents was carried out to determine the basic features of the structure responsible for the observed biological activity. The substituents ester or carboxylic acid on the coumarin ring were needed to have potent inhibitory activity against both Gram-positive and Gram-negative bacteria. The presence of phenolic hydroxyl group and/or carboxylic acid was necessary to possess higher activity against Helicobacter pylori.

Brominations of steroidal hormone having alpha,beta-unsaturated ketone, 17-O-acetyltestosterone, in the presence of silver triflate

Bromination of 17-O-acetyltestosterone (17beta-acetoxyandrost-4-en-3-one) (1) was performed with 1, 5, and 10 eq of Br2 in AcOH-Et2O at room temperature. In all cases 2alpha,6beta- (2) and 2alpha,6beta-dibromo-17beta-acetoxyandrost-4-en-3-one (3) were obtained, although the yields were dependent upon the conditions used. Bromination of compound 1 with 10 eq of Br2 in the presence of silver trifluoromethanesulfonate (silver triflate, AgOTf) at room temperature for 12 h gave 2,7alpha-dibromo- (4) and 2,4,7alpha-tribromo-17beta-acetoxy-3-hydroxy-1-methylestra-1,3,5(10)-triene-6-one (5). The formations of the products were inferred on the basis of products obtained under controlled brominations of 1 in the presence of AgOTf, and of those obtained by the brominations of compounds 9-13 also in the presence of AgOTf.

Enhanced antibacterial effect of erythromycin in the presence of 3,5-dibenzoyl-1,4-dihydropyridines

Fifteen 3,5-dibenzoyl-1,4-dihydropyridines (BzDHP, GB1-GB15) (nifedipine (NP) analogs) were tested on three different E. coli strains. The compounds had relatively high MIC values on these strains. In combination with erythromycin (Er), compounds (G1,3,4,6,7,10,12) reduced MIC values of Er. When the BzDHPs were tested on E. coli Gy-1/Apsen.Erres strain isolated from a clinical specimen, the reduction of MIC values were similar to the previous strains, but not identical. In the polyresistant clinically isolated E. coli Gy-2/Apres.Erres strain, the MIC values of Er were slightly reduced in the presence of GB1-GB7. Compound GB12 was the most effective in enhancing the activity of Er, and was selected for plasmid elimination studies. However, GB12 itself had no antiplasmid effect and did not alter the promethazine induced plasmid elimination.

Transdermal delivery of the potent analgesic dihydroetorphine: kinetic analysis of skin permeation and analgesic effect in the hairless rat

Dihydroetorphine is an extraordinarily strong opioid analgesic. To assess its effectiveness after topical application in hairless rats we have examined the kinetic analysis of skin permeation through excised skin and the in-vitro reservoir effect of skin, and have investigated the predictability of plasma concentration and analgesic effect following in-vivo transdermal application. Dihydroetorphine was moderately permeable from an aqueous suspension through excised hairless rat skin. Dihydroetorphine flux from drug-dispersed pressure-sensitive adhesive tape was threefold that from the applied aqueous suspension. The fluxes through the abdominal and the dorsal skin during tape application fitted the Fickian diffusion equation well after the tape was removed peeling off the outer layer of the stratum corneum. The relationship between the plasma concentration and the analgesic effect was examined for four different rates of infusion of dihydroetorphine. A non-linear pharmacokinetic disposition was observed. Following abdominal (0.28 cm2, 20 microg) and dorsal (0.50 cm2, 35 microg) applications of the dihydroetorphine tape, plasma concentration (0.2-0.8 ng mL(-1)) and analgesic effect were maintained at a suitable level, for more than 8 h, until removal of the tape. These profiles were predictable using the combined equation for percutaneous absorption, disposition and the analgesic effect, but the analgesic effect was slightly lower than the predicted value. The results show that it was possible to control the plasma concentration and the analgesic effect of dihydroetorphine by topical application of the analgesic using pressure-sensitive adhesive tape in the hairless rat. It was possible to predict the result using mathematical modelling.

Antitumor potential and possible targets of phenothiazine-related compounds

Phenothiazines and its related compounds have shown diverse biological activities including psychotropic, anticancer and other pharmacological activities. Recent studies have suggested the possible interactions between phenothiazines and their physiological targets or potential receptors. New types of phenothiazine, such as "half-mustard type" phenothiazines and benzo[a]phenothiazines, have been synthesized. These compounds stimulated T-cell blast formation, natural killer cell activity (possibly via activation of monocytes and macrophages) and antibody-dependent cellular cytotoxicity of human peripheral blood mononuclear cells, and showed cytotoxicity against several human cancer cell lines. Benzo[a]phenothiazines induced monocytic differentiation and apoptotic cell death (characterized by internucleosomal DNA fragmentation) in human myelogenous leukemic cell lines, but not in other cancer cell lines. These compounds also induced antimicrobial activity in vivo, possibly by host-mediated immunopotentiation. On the other hand, phenothiazines did not induce such immunopotentiation activity, but showed direct antibacterial activity in vitro. There was positive relation between their radical intensity and biological activities. These compounds did not show any apparent mutagenic activity, but rather be antimutagenic. These data suggest their possible applicability of "half-mustard type" phenothiazines and benzo[a]phenothiazines for cancer chemotherapy.

Distinctive distribution of human papillomavirus type 16 and type 20 DNA in the tonsillar and the skin carcinomas of a patient with epidermodysplasia verruciformis

BACKGROUND

Epidermodysplasia verruciformis (EV) is a rare skin disease characterized by disseminated pityriasis versicolor-like or flat wart-like lesions and by the development of skin carcinomas. It is well established that specific cutaneous human papillomaviruses (EV-HPVs) are associated with both benign and malignant skin lesions in EV patients. However, little is known of the relationship between HPV and the mucosal lesions of EV patients.

OBJECTIVES

To detect and identify HPV types associated with skin and mucosal lesions of an EV patient.

PATIENT/METHODS

We investigated the skin carcinoma and the coexisting tonsillar carcinoma of a 41-year-old man with EV. Histopathologically, both lesions were squamous cell carcinomas. We analysed these two lesions by immunohistochemistry, in situ hybridization, and by molecular virology.

RESULTS

Neither skin nor tonsillar lesions exhibited positivity for HPV capsid antigen by immunohistochemistry. By Southern blot hybridization, however, the skin carcinoma harboured 'EV-specific' HPV20 DNA, while the tonsillar carcinoma harboured 'genital' HPV16 DNA. In addition, in situ hybridization localized the respective viral DNA in the corresponding lesion.

CONCLUSIONS

The results indicate that EV-HPV could be responsible for the development of the skin carcinoma, but not the mucosal carcinoma in this patient.

Biological activity of feijoa peel extracts

Fractionated extracts of Feijoa peels were studied for cytotoxic activity, anti-human immunodeficiency virus (HIV) activity and antibacterial activity. Two most cytotoxic fractions A3 of acetone extract and M2 of methanol extract had potent inhibitory activity against Gram-positive and Gram-negative bacteria as well as fungi tested. Fraction A4 of acetone extract showed multidrug resistance (MDR)-reversal activity comparable with that of verapamil (positive control). These results indicate the therapeutic value of Feijoa peel extracts as potential antimicrobial and MDR-modulating agents.

Ganglioside GD3 and its mimetics induce cytochrome c release from mitochondria

Ganglioside GD3 induced the release of cytochrome c from isolated rat liver mitochondria. This process was completely prevented by cyclosporin A and partially prevented by a cysteine protease inhibitor, n-acetyl-leu-leu-norleucinal. Cyclosporin A is a potent inhibitor of the permeability transition pore, whereas n-acetyl-leu-leu-norleucinal has no effect on this pore. These results indicate that the release of cytochrome c from mitochondria requires both the opening of the permeability transition pore and a cysteine protease inhibitor-sensitive mechanism. Gangliosides GD1a, GD1b, GT1b, and GQ1b along with the synthetic GD3 mimetics TMS-42 and CI-22, which are glycerophospholipids carrying a disialo residue, also induced cytochrome c release. In contrast, gangliosides GM1, GM2, and GM3 did not induce cytochrome c release. These results indicate that two sialo residues must play an important role in the induction of cytochrome c release by gangliosides.

Antioxidative activity of (-)-epigallocatechin-3-(3''-O-methyl)gallate isolated from fresh tea leaf and preliminary results on its biological activity

Antioxidative activity of (-)-epigallocatechin-3-(3''-O-methyl)gallate (catechin e) was examined. Catechin e showed a strong antioxidative activity. A preliminary test using rat cancer cells suggests that catechin e also has a strong cytotoxic activity. Among tested catechins, only catechin e has strong activity for both.

Effect of hypotension severity on hippocampal CA1 neurons in a rat global ischemia model

Neuronal death in the hippocampal CA1 subregion has been shown to occur in a delayed manner after transient global ischemia. The 2-vessel occlusion model is one of the most frequently used global ischemia paradigms in rodents. Although researchers often fail to induce bilateral delayed CA1 neuronal death, the importance of hypotension severity has not been fully discussed. We induced 10 min of global ischemia with 2-vessel occlusion and various severities of hypotension in rats, and the subsequent neuronal damage and neurogenesis in the hippocampal CA1 pyramidal cell layer were immunohistochemically studied. Neuronal apoptosis after global ischemia was also characterized by terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end labeling (TUNEL). The mean arterial blood pressure of 31-35 mmHg was the most appropriate range of hypotension in this model because of low mortality and consistent bilateral CA1 injury. Most of the neurons in the CA1 pyramidal cell layer lost neuron specific nuclear protein and became TUNEL-positive 3 days after ischemia. There was no evidence of apoptosis or neurogenesis at 7-28 days. There were ischemia-tolerant neurons in the CA1 pyramidal cell layer that survived delayed neurodegeneration, however, further studies are necessary to characterize the property of these neurons.

[Spinal anesthesia for a patient with epidermolysis bullosa hereditaria dystrophica]

A 39-year-old male with epidermolysis bullosa hereditaria dystrophica was scheduled for surgical excision of squamous cell carcinoma in the lower leg. Spinal anesthesia was chosen, because the skin of the puncture site for spinal anesthesia appeared to be dry and scarred, and to have less chance of infection. To avoid shear stress to the skin, we carefully performed anesthetic management including attachment of equipments associated with anesthesia, monitoring and surgery. However, we experienced some troubles and complications associated with anesthetic technique, such as pain on removing a dressing sheet, burning sensations induced by alcoholic stimuli for cold sign test and tent-like traction of the punctured skin on withdrawing the spinal needle.

Convenient synthesis of alpha-trifluoromethylated acyloins from alpha-hydroxy or alpha-amino acids

Alpha-trifluoromethylated acyloins (2 and 6) have been prepared from alpha-hydroxy acids (1), N-acylprolines (5) or N-acyl-N-alkyl alpha-amino acids (8) by novel transformation reactions with trifluoroacetic anhydride (TFAA) in the presence of pyridine. The former reaction of 1 could proceed through mesoionic 1,3-dioxolium-4-olates, whereas the latter two reactions of alpha-amino acids (5 and 8) could involve mesoionic 1,3-oxazolium-5-olates. The reaction of 1 with TFAA shows more potential for practical applications because of the ready availability of the starting materials and ease of manipulation.

Heart rate variability during massive hemorrhage and progressive hemorrhagic shock in dogs

PURPOSE

To investigate the sequential changes in heart rate (HR), autonomic nervous activity presented by the spectral analysis of heart rate variability (HRV), hemodynamics and metabolism during massive hemorrhage and progressive hemorrhagic shock in dogs.

METHODS

Twelve dogs were subjected to acute massive hemorrhage until mean arterial pressure (MAP) reached 50 mm Hg. Then bleeding was stopped and they were allowed to reach a plateau phase. They were divided, post hoc, into bradycardic or tachycardic groups according to their HR response to the acute massive hemorrhage. After reaching a plateau phase, the dogs were further bled to keep their MAP around 50 mmHg (progressive hemorrhagic shock). Their heart rate power spectra were quantified into low-frequency (LF) (0.04-0.15 Hz) and high-frequency (HF) (0.15-0.4 Hz) components.

RESULTS

In the bradycardic group, both LF and HF increased after massive hemorrhage, but during progressive hemorrhagic shock these components decreased while HR increased. In the tachycardic group, LF increased after massive hemorrhage, but during progressive hemorrhagic shock LF decreased with continuous suppression of HF CONCLUSION: Massive hemorrhage caused two types of HR response: bradycardia and tachycardia. The HRV profile showed differential autonomic characteristics, and could be a valuable tool in assessing various degrees of hemorrhagic shock.

[Surgical treatment for mitral regurgitation: mid-term outcome following mitral valve repair]

Mid-term results of mitral valve repair for mitral regurgitation were evaluated in 173 consecutive patients (mean age 53 years, 107 males, 66 females) treated from July 1991 to March 1998. Pathological causes of the mitral valve disease were degenerative in 118 patients, infective endocarditis in 25, rheumatic in 13, and ischemic in 8 (ischemic cardiomyopathy in 7). The principal technique was chordal replacement with expanded polytetrafluoroethylene sutures for prolapse of the anterior leaflet, and Carpentier's sliding leaflet technique for prolapse of the posterior leaflet. Most patients received ring annuloplasty with a rigid ring and flexible band (physiological remodeling annuloplasty). Intraoperative transesophageal echocardiography was used after 1993. There were 7 operative deaths (4%) and 7 mitral valve replacements (4%) during the same operation. Successful repair was achieved in 96% of patients with mitral regurgitation. Mean follow-up was 35 months (range 2 to 78 months). Survival at 6 years was 85 +/- 10% of all patients, 98 +/- 2% in degenerative cases. Six patients required reoperation (1.2%/patient-year) and mean time interval between initial operation and reoperation was 33.1 months. Four patients with atrial fibrillation had thromboembolic events (0.8%/patient-year). There were no anticoagulant-related complications. Freedom from reoperation and all valve-related event at 6 years was 88 +/- 6% and 84 +/- 6%. Late postoperative Doppler echocardiography revealed satisfactory results in 93% of the patients. Mitral valve repair using chordal replacement, sliding plasty and ring annuloplasty provides excellent mid-term results.

Spirostanols obtained by cyclization of pseudosaponin derivatives and comparison of anti-platelet agglutination activities of spirostanol glycosides

Naturally occurring saponins 3 and 4 have a normal type F ring and alpha-arranged CH(3)-21 group. Treatments of pseudosaponin peracetates 18 and 19 derived from 3 and 4, respectively, with alcoholic KOH, followed by acidification with acetic acid, gave spirostanols 20 and 22 having iso type F rings as major products. Structural analyses of sapogenins and saponins derived from pseudo derivatives 11, 12, 18 and 19 were performed by comparisons of their 1H-NMR spectral data and the X-ray analytical data of 3-O-p-bromobenzoyl sarsasapogenin 7, 3-O-acetyl diosgenin 13 and saponin 20. The mechanisms of ring-closure reaction of the side chain at C-22 of pseudosapogenins and pseudosaponins were deduced using stereomodels of the spirostanols derived from 11 under various reaction conditions. Inhibitory activities of saponin diglycosides 3, 4, 20, 21 and 25 on human platelet agglutinations induced by ADP and ristocetin were compared.

The cytosolic antioxidant copper/zinc-superoxide dismutase prevents the early release of mitochondrial cytochrome c in ischemic brain after transient focal cerebral ischemia in mice

Release of mitochondrial cytochrome c into the cytosol is a critical step in apoptosis. We have reported that early release of cytochrome c in vivo occurs after permanent focal cerebral ischemia (FCI) and is mediated by the mitochondrial antioxidant manganese superoxide dismutase (SOD). However, the role of reactive oxygen species produced after ischemia-reperfusion in the mitochondrial apoptosis process is still unknown, although overexpression of copper/zinc-SOD (SOD1), a cytosolic isoenzyme, protects against ischemia-reperfusion. We now hypothesize that the overexpression of SOD1 also prevents apoptosis after FCI. To address this issue, we examined the subcellular distribution of the cytochrome c protein in both wild-type mice and in SOD1 transgenic (Tg) mice after transient FCI. Cytosolic cytochrome c was detected as early as 2 hr after reperfusion, and correspondingly, mitochondrial cytochrome c was significantly reduced after FCI. Cytosolic cytochrome c was significantly lower in the SOD1 Tg mice compared with wild types 2 (p < 0.0001) and 4 (p < 0.05) hr after FCI. Apaf-1, which interacts with cytochrome c and activates caspases, was constitutively expressed in both groups of animals, with no alteration after FCI. Double staining with cytochrome c immunohistochemistry and terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end labeling showed a spatial relationship between cytosolic cytochrome c expression and DNA fragmentation. A significant amount of DNA laddering was detected 24 hr after ischemia and was reduced in SOD1 Tg mice. These data suggest that SOD1 blocks cytosolic release of cytochrome c and could thereby reduce apoptosis after transient FCI.

Quantitative determination of dihydroetorphine in rat plasma and brain by liquid chromatography-tandem mass spectrometry

The extraordinarily strong analgesic dihydroetorphine (DHE) was registered as one of the most strictly controlled narcotic drugs by the United Nations in 1999. However, an effective detection method for DHE in biological samples has not yet been established. We developed a quantitative method for assay of DHE in rat plasma and brain by liquid chromatography-tandem mass spectrometry equipped with an ionspray interface. A 0.5-ml volume of plasma and brain homogenate spiked with buprenorphine (internal standard) was purified by the solid-phase extraction column Bond Elute Certify. DHE produced numerous weak fragment ions by collision induced dissociation. Therefore, collision energy was utilized to decompose the interferences, and the protonated molecular ion was used for both precursor and product ion monitoring. As a result of the method validation, the dynamic concentration range was determined as 0.05-10 ng/ml. DHE in these samples was stable for 2 months at -4 degrees C and for 24 h at ambient temperatures. Using the present method, DHE was detected in rat plasma and brain tissue after intravenous injection (0.5 microg/kg).

Chemistry and biological activity of new 3-benzazepines

This review summarizes our experiments investigating structure-activity relationships of 3-benzazepines. Three 7, 8-dihydroxy-3-benzazepines [7-9] were cytotoxic to human promyelotic leukaemia HL-60 cells. Compound [9] showed the highest cytotoxicity and the activity was twice as high as that of dopamine (DA, [11]). Three active compounds [7-9] produced radicals, whereas other less potent benzazepines [1-6, 10] did not produce radicals. Furthermore, cytotoxic 3-benzazepines [7-9] also enhanced the decay of ascorbic acid in rat brain homogenate. Two 7,8-dimethoxy-3-benzazepines [5, 10] were able to form a complex with the replicative form of plasmid DNA. The multidrug resistance (MDR) P-glycoprotein (Pgp) efflux pump of mouse lymphoma cells was inhibited by three compounds [5, 8, 10]. Compound [8] has the highest activity in MDR reversal and is two times more potent than verapamil. Three cytotoxic 3-benzazepines [7-9] showed inhibitory effects against reverse transcriptase (RT) of Moloney leukemia.

Immunomodulating effect of 2,3,4,5-tetrahydro-1H-3-benzazepines (a new class of non-nucleoside inhibitors of reverse transcriptase)

The effects of newly synthesized, reverse transcriptase inhibitors, 3-benzazepines, for their effects on natural killer (NK) cell and blast transformation in human peripheral blood mononuclear cells were investigated. The most effective reverse transcriptase inhibitors were KF1, KF2 and KF3, which primarily suppressed immunological functions. Besides the inhibition of T cell proliferation, the benzazepines also show inhibitory effect on NK cell functions, in particularly, against large granular lymphocytes and monocytes. The B lymphocytes and Fc mediated killer functions were less inhibited.

Synthesis and biological activity of N-acylphenothiazines

Previous studies have demonstrated the relationship between radical intensity and cytotoxic activity in water-soluble compounds. This relationship was investigated in lipophilic compounds. Several N-acylphenothiazines showed higher cytotoxic activity against human leukemic and squamous carcinoma cell lines than phenothiazine, the parent compound. Electron spin resonance (ESR) spectroscopy showed that these active compounds produced much lower amounts of radicals than phenothiazine. Several compounds failed to inhibit the cytopathic effects of human immunodeficiency virus (HIV) infection in MT-4 cells. It suggested that the radical-mediated-mechanisms has not involved in the induction of cytotoxic activity by lipophilic compounds, such as N-acylphenothiazines.