Pentoxifylline potentiates nitric oxide production in interleukin-1beta-stimulated vascular smooth muscle cells through cyclic AMP-dependent protein kinase A pathway

In the present study, we observed that pentoxifylline (PTX) significantly augmented the nitric oxide (NO) production and the iNOS gene expression by interleukin-1beta (IL-1beta)-stimulated vascular smooth muscle cells (VSMCs). The enhancing effects of PTX on the IL-1beta-induced NO production was associated with an increased intracellular cyclic AMP (cAMP) levels, and the synergistic effects of PTX on the IL-1beta-induced NO production was blocked by cAMP-dependent protein kinase A (PKA) inhibitors. PKA inhibitors, KT5720 and H89, markedly decreased the augmented expression of iNOS gene whereas ODQ, a soluble guanylate cyclase inhibitor, did not affect the enhancing effect. In addition, the pretreatment with KT5720 or H89 abolished the increased translocation of the p65 subunit of NF-kappaB into the nucleus by PTX in the IL-1beta-stimulated VSMCs. These results suggest that enhancing effects of PTX on the iNOS gene expression in the IL-1beta-stimulated VSMCs is mediated predominantly through the activation of NF-kappaB via cAMP-dependent PKA pathway.

The role of E-cadherin expression in non-small cell lung cancer

The purpose of this study is to evaluate the clinical significance of E-cadherin expression in lung cancer. E-cadherin expression was detected by immunohistochemistry using a monoclonal antibody (HECD-1). Strongly positive (++) E-cadherin tumors were classified as a type of preserved E-cadherin expression (Pr type), while the others (+, - tumors) were classified as a type of reduced E-cadherin expression (Rd type). The frequency of Pr type in squamous cell carcinomas (59.0%) was higher than Rd type. However, in adenocarcinomas, the frequency of Rd type was higher than Pr type. E-cadherin expression pattern was significantly correlated with differentiated state (Pearson correlation coefficient 0.394, p<0.001). E-cadherin expression of well-differentiated tumors was more frequently preserved than that of poorly differentiated tumors (60.0% vs. 25.9%). With regard to the correlation between E-cadherin expression and stages of lymph node metastasis in non-small cell lung cancers, the percentage of tumors with Pr type E-cadherin expression declined from 66.3% (< or = N1) to 38.6% (> or = N2), indicating that loss of E-cadherin expression is responsible for acquisition of invasive potential of lung cancer as well as the possible role of E-cadherin in the histological differentiation of lung cancer.

Lavandulylflavonoids: a new class of in vitro apoptogenic agents from Sophora flavescens

The root of Sophora flavescens has been reported to possess antitumor activity in Sarcoma 180, lymphoid leukemia 1210 and melanotic melanoma. We have isolated four cytotoxic flavonoids with a lavandulyl side-chain at C8 and tested for their effects on human myeloid leukemia HL-60 cells and human hepatocarcinoma HepG2 cells, in terms of inhibition of proliferation and induction of apoptosis. They showed potent antiproliferative effects with IC(50) values from 11.3 microM to 18.5 microM in HL60 cells and from 13.3 microM to 36. 2 microM in HepG2 cells. Treatment of HL-60 cells with the lavandulylflavonoids induced apoptosis in a dose-dependent manner. Apoptosis was judged by the detection of DNA fragmentation by agarose gel electrophoresis and the degree of apoptosis was quantified by a sandwich enzyme immunoassay. The hydration of C4"'C5"' double bond with or without C3 hydroxylation caused a complete loss of cytotoxicity. These results suggest that the lavandulyl side-chain is essential for the activity of the flavonoids isolated from S. flavescens which may be used as cancer chemotherapeutic and chemopreventive agents.

Foreign bodies in sarcoidosis

Sarcoidosis is a multisystem disease of unknown etiology. The demonstration of polarizable foreign bodies in cutaneous granulomas is generally thought to exclude a diagnosis of sarcoidosis. Nevertheless. some investigators have reported systemic sarcoidosis with cutaneous manifestations in which polarizable particles were associated with granuloma formation in the skin. We searched the biopsy specimens of granulomatous lesions from 50 patients with cutaneous sarcoidosis using polarization microscopy to estimate the frequency of polarizable foreign bodies in cutaneous lesions of sarcoidosis. Using electron probe microanalysis, we sought to determine what elements compose these foreign bodies. Polarizable foreign bodies were found in the granulomatous skin lesions of 12 of 50 patients with cutaneous sarcoidosis. All 12 patients also had at least one other granulomatous systemic lesion, and 4 had biopsy specimens of a systemic lesion available for review. Polarizable foreign bodies were found in two cases. The elements identified were calcium, phosphorus, silicon, and aluminum. Polarizable foreign bodies were found in cutaneous sarcoidosis far more often than expected. Foreign bodies were also found in granulomatous systemic lesions. The foreign body may serve as an inciting stimulus for granuloma formation in selected cases of sarcoidosis.

Polymethoxyflavonoids from Vitex rotundifolia inhibit proliferation by inducing apoptosis in human myeloid leukemia cells

Three polymethoxyflavonoids from the fruit of Vitex rotundifolia, namely 2',3',5-trihydroxy-3,6,7-trimethoxyflavone (Vx-1), vitexicarpin (Vx-5) and artemetin (Vx-6), were tested for their antiproliferative activity in human myeloid leukemia HL-60 cells. They showed a dose-dependent decrease in the growth of HL-60 cells. The concentrations required for 50% inhibition of the growth (IC50) after 96 h were 4.03 microM, 0.12 microM and 30.98 microM for Vx-1, Vx-5 and Vx-6, respectively. Treatment of HL-60 cells with the flavonoids induced morphological changes that are characteristic of apoptosis. We judged the induction of apoptosis by the detection of DNA fragmentation in agarose gel electrophoresis and the degree of apoptosis was quantified by a double-antibody sandwich ELISA and by flow cytometric analysis. The C-3 hydroxyl and C-8 methoxyl groups were found not to be essential for the activity, but the C-3' methoxyl instead of hydroxyl group lowered the antiproliferative and apoptosis inducing activity. These results suggest that the polymethoxyflavonoids isolated from V. rotundifolia may be used as potential chemopreventive and chemotherapeutic agents.

The biosynthesis of hepatic cholesterol esters and triglycerides is impaired in mice with a disruption of the gene for stearoyl-CoA desaturase 1

Stearoyl-CoA desaturase (SCD) is a microsomal enzyme required for the biosynthesis of oleate and palmitoleate, which are the major monounsaturated fatty acids of membrane phospholipids, triglycerides, and cholesterol esters. Two well characterized isoforms of SCD, SCD1 and SCD2, exist in the mouse. Most mouse tissues express SCD1 and 2 with the exception of the liver, which expresses mainly the SCD1 isoform. We found that asebia mice homozygous for a natural mutation of the gene for SCD1 (SCD-/-) are deficient in hepatic cholesterol esters and triglycerides despite the presence of normal activities of acyl-CoA:cholesterol acyltransferase and glycerol phosphate acyltransferase, the enzymes responsible for cholesterol ester and triglyceride synthesis, respectively, in the liver of these mice. Feeding diets supplemented with triolein or tripalmitolein to the SCD-/- mice resulted in an increase in the levels of 16:1 and 18:1 in the liver but failed to restore the 18:1 and 16:1 levels of the cholesterol ester and triglycerides to the levels found in normal mice. The SCD-/- mouse had very low levels of triglycerides in the VLDL and LDL lipoprotein fractions compared with the normal animal. Transient transfection of an SCD1 expression vector into Chinese hamster ovary cells resulted in increased SCD activity and esterification of cholesterol to cholesterol esters. Taken together, our observations demonstrate that the oleoyl-CoA and palmitoleyl-CoA produced by SCD1 are necessary to synthesize enough cholesterol esters and triglycerides in the liver and suggest that regulation of SCD1 activity plays an important role in mechanisms of cellular cholesterol homeostasis.

Thermosoftening treatment of the nasotracheal tube before intubation can reduce epistaxis and nasal damage

We evaluated whether a thermosoftening treatment with warm saline of a nasotracheal preformed tube can improve navigability through the nasal passageways and reduce epistaxis and nasal damage. A total of 150 patients were randomly allocated to three groups: Group I (untreated tube group, n = 50), Group II (35 degrees C treated tube group, n = 50), and Group III (45 degrees C treated tube group, n = 50). In Groups II and III, the tubes were softened at 35 +/- 2 degrees C and 45 +/- 2 degrees C with warm saline, respectively. In Group I the tube was prepared at room temperature (25 +/- 2 degrees C). The incidence of epistaxis and nasal damage in Groups II and III was significantly less than that of Group I (P: < 0.05). Despite the more frequent incidence of smooth passage in Group III, no statistical difference was found among the groups. Logistic regression analysis also confirmed that epistaxis was more likely to be reduced when the tube had been thermosoftened (odds ratio = 1.46, 95% confidence interval = 1.02, 2.11). We conclude that simple thermosoftening treatment of the nasotracheal tube with warm saline helps to reduce epistaxis and nasal damage.

IMPLICATIONS

Thermosoftening treatment of a nasotracheal tube with warm saline before intubation can effectively reduce epistaxis and nasal damage. This technique is safe, easy, and suitable for all types of tubes and does not require additional implements.

A case of intramuscular hemangioma of the back

Intramuscular hemangioma is an uncommon tumor that usually involves an extremity. They rarely occur after the age of 30. We report a case of an intramuscular hemangioma occurring on the back of a 39-year-old man. Histopathologically, the tumor consisted mainly of large vessels between the muscle fibers. Phleboliths were observed in some of the vessel walls.

LCC, a cerebroside from Lycium chinense, protects primary cultured rat hepatocytes exposed to galactosamine

Primary cultures of rat hepatocytes exposed to galactosamine (GalN) were used as a screening system to assess whether a new cerebroside, LCC, isolated from the fruits of Lycium chinense, exhibits hepatoprotective activity. Cultured rat hepatocytes injured with GalN routinely release glutamic pyruvic transaminase (GPT) and sorbitol dehydrogenase (SDH) into the culture medium. Treatment of these GalN-injured primary cultures with LCC markedly blocked the release of both GPT and SDH in a dose-dependent manner over concentrations of LCC ranging from 1 microM to 10 microM. To investigate the mechanism of action for the hepatoprotective activity of LCC, the extent of [(3)H]-uridine incorporation into RNA was measured in GalN-injured cultures of rat hepatocytes. [(3)H]-Uridine incorporation was significantly decreased in injured hepatocytes. LCC, however significantly restored the incorporation of [(3)H]-uridine into RNA in a dose-dependent manner over concentrations ranging from 1 microM to 10 microM. LCC also blocked the suppression of RNA synthesis caused by actinomycin D in a dose-dependent manner. These data suggest that LCC may have prominent hepatoprotective activity and that its therapeutic value should be investigated further.

Selective activation of the c-Jun N-terminal protein kinase pathway during 4-hydroxynonenal-induced apoptosis of PC12 cells

The by-product of lipid peroxidation, 4-hydroxynonenal (HNE), was shown to cause apoptosis in PC12 cells. In this study, we investigated the molecular mechanism of HNE-induced apoptosis in these cells. Specifically, we determined the effect of HNE on the activities of mitogen-activated protein (MAP) kinases involved in early signal transduction. Within 15 to 30 min after HNE treatment, c-Jun N-terminal protein kinase (JNK) was maximally activated, before it returned to control level at 1 h post-treatment. In contrast, activities of extracellular signal-regulated kinase and p38 MAP kinase remained unchanged from their baseline levels. Stress-activated protein kinase kinase (SEK1), an upstream kinase of JNK, was also activated within 5 min after HNE treatment and remained activated for up to 60 min. Marked activation of the JNK pathway through SEK1 and apoptosis signal-regulating kinase 1 (ASK1), an upstream kinase of SEK1, was demonstrated by the transient transfection of cDNA for wild-type SEK1 or ASK1 together with JNK into COS-7 cells. Furthermore, significant reductions in JNK activation and HNE-induced cell death were observed when either of the dominant negative mutant of SEK1 or ASK1 was cotransfected with JNK. Pretreatment of PC12 cells with a survival-promoting agent, 8-(4-chlorophenylthio)-cAMP, prevented both the HNE-induced JNK activation and apoptosis. Nonaldehyde, a nontoxic aldehyde, neither caused apoptosis nor JNK activation. Pretreatment of PC12 cells with SB203580, a specific inhibitor of p38 MAP kinase, had no effect on HNE-induced apoptosis. All these data suggest that the selective JNK activation by HNE is critical for the apoptosis of PC12 cells and that the HNE-mediated apoptosis is likely to be mediated through the activation of the ASK1-SEK1-JNK pathway without activation of extracellular signal-regulated kinase or p38 MAP kinase.

The effect of herpesvirus infection on the expression of cell adhesion molecules on cultured human dermal microvascular endothelial cells

Cell-mediated immune response to herpes simplex virus (HSV) may be important in the pathogenesis of herpes keratitis, erythema multiforme or Behcet's disease. We examined whether herpesvirus infection regulates the expression of cell adhesion molecules on cultured human dermal microvascular endothelial cells (HDMEC) and the regulation of T-lymphocytes binding to HDMEC. The expression of intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), or E-selectin on HDMEC increased significantly after treatment with HSV-1, HSV-2, or measles virus on HDMEC. Anti-IL-1 alpha antibody or anti-TNF alpha antibody partially inhibited the expression of ICAM-1, VCAM-1, or E-selectin on HDMEC. The binding of T-lymphocytes to HDMEC increased significantly after the treatment of HSV-1 or measles virus on HDMEC. The binding of T-lymphocytes to HDMEC was significantly inhibited after 16 h of incubation following treatment with anti-ICAM-1 antibody, anti-IL-1 alpha antibody or anti-TNF alpha antibody to HDMEC. These study results suggest that HSV induces the increased expression of ICAM-1, or induction of VCAM-1 and E-selectin on HDMEC and that among these adhesion molecules, the expression of ICAM-1 on HDMEC mainly regulates the binding of T-lymphocytes to HDMEC. The data also suggest that IL-1 alpha or TNF alpha which was produced by HSV infected HDMEC may be related to these events.

Antioxidant lignans from Machilus thunbergii protect CCl4-injured primary cultures of rat hepatocytes

Eleven lignans (1-11) were isolated from the CH2Cl2 fraction of the bark of Machilus thunbergii Sieb. et Zucc. (Lauraceae). These were identified as (-)-acuminatin (1), (-)-isoguaiacin (2), meso-dihydroguaiaretic acid (3), (+)-galbacin (4), (-)-sesamin (5), (+)-galbelgin (6), machilin A (7), machilin G (8), licarin A (9), and nectandrin A (10) and B (11). Primary cultures of rat hepatocytes were co-incubated for 90 min with the hepatotoxin CCl4 and each of the 11 lignans (50 microM). Hepatoprotective activity was determined by measuring the level of glutamic pyruvic transaminase released into the medium from the primary cultures of rat hepatocytes. (-)-Acuminatin, (-)-isoguaiacin and meso-dihydroguaiaretic acid all significantly reduced the level of glutamic pyruvic transaminase released. Further investigation revealed that these three compounds significantly preserved the levels and the activities of glutathione, superoxide dismutase, glutathione peroxidase and catalase. (-)-Acuminatin, (-)-isoguaiacin and meso-dihydroguaiaretic acid also ameliorated lipid peroxidation as demonstrated by a reduction of malondialdehyde production. These results suggest that (-)-acuminatin, (-)-isoguaiacin and meso-dihydroguaiaretic acid exert diverse hepatoprotective activities, perhaps by serving as potent antioxidants.

Nodular hidradenocarcinoma with prominent squamous differentiation: case report and immunohistochemical study

We report the case of a 24-year-old woman with nodular hidradenocarcinoma on the scalp. While histopathology of the tumor showed a circumscribed, lobulated intradermal mass with prominent squamous differentiation, the immunohistochemical study with antibodies to cytokeratins, CAM 5.2 and 19, epithelial membrane antigen, carcinoembryonic antigen, S-100 protein and p53 all demonstrated positivity. These findings confirmed that the tumor was of eccrine sweat gland origin and it was thought to be a nodular hidradenocarcinoma differentiating toward the eccrine duct and/or secretory portions. She was treated with a wide local excision and no recurrence was observed 18 months after excision.

Factors involved in hepatic glutathione depletion induced by acute ethanol administration

Factors implicated in changes of the hepatic glutathione concentration following acute ethanol administration were examined in rats. Adult female rats were treated with either ethanol (4 g/kg, p.o.) or an isocaloric glucose solution. The hepatic reduced glutathione (GSH) concentration decreased rapidly after ethanol intake with a maximum diminution, approximately 50% of the control value, being observed at t = 6 h. The hepatic GSH concentration gradually increased, and finally rebounded at 24 h after ethanol ingestion. The dose of ethanol induced a transient increase in the oxidized glutathione (GSSG)/GSH ratio, which was associated with a significant reduction in GSH rather than elevation in GSSG [corrected]. The activity of gamma-glutamylcysteine synthetase (GCS), the rate-limiting enzyme for glutathione synthesis, and the cysteine concentration in liver were also measured. The GCS activity was depressed to approximately 80% of the control value at t = 2.5 h followed by rapid recovery, but no difference in the hepatic cysteine concentration between control and ethanol treated rats was observed for 24 h, suggesting that the reduction in glutathione synthesis may not play a major role in the significant depletion of this tripeptide in liver. The total glutathione concentration was measured both in prehepatic and posthepatic inferior vena cava blood. The glutathione concentration in posthepatic blood was approximately twice as high as that of prehepatic blood in control rats. Acute ethanol administration doubled the elevation of glutathione in posthepatic blood measured at t = 2.5 h. The sinusoidal efflux of glutathione estimated from the increase in blood glutathione concentration was greater than the total amount of its depletion in the liver of rats treated with ethanol. The results suggest that in the liver of rats treated acutely with ethanol, glutathione efflux plays the most important role in the reduction of this tripeptide, which would be aggravated by a transient decrease in glutathione synthesis and by increased consumption in association with its metabolism.

The trans-10,cis-12 isomer of conjugated linoleic acid downregulates stearoyl-CoA desaturase 1 gene expression in 3T3-L1 adipocytes

Conjugated linoleic acids (CLA) are a group of positional and geometric conjugated dienoic isomers of linoleic acid. The objective of this study was to determine the effects of the cis-9,trans-11 and trans-10,cis-12 isomers of conjugated linoleic acid on lipid composition and gene expression during the differentiation of mouse 3T3-L1 preadipocytes. Treatment of differentiating 3T3-L1 preadipocytes with trans-10,cis-12 conjugated linoleic acid (CLA) resulted in a dose-dependent decrease in the expression of the stearoyl-CoA desaturase 1 gene (SCD1). The expression of other adipocyte genes such as adipose P2 (aP2), fatty acid synthase (FAS), SCD2 and the key adipogenic transcription factors, peroxisome proliferator-activated receptor gamma2 (PPARgamma2) and CCAAT enhancer binding protein alpha (C/EBPalpha), remained elevated. Cells treated with trans-10,cis-12 CLA exhibited smaller lipid droplets, with reduced levels of the major monounsaturated fatty acids, palmitoleate and oleate. By contrast, the cis-9,trans-11 isomer did not alter adipocyte gene expression. Repression of the stearoyl-CoA desaturase gene expression in adipocytes by the trans-10,cis-12 isomer may contribute to the mechanisms by which CLA reduces body fat in mice.

Comparison of Tc-99m sestamibi, serum neuron-specific enolase and lactate dehydrogenase as predictors of response to chemotherapy in small cell lung cancer

Neuron-specific enolase (NSE) and lactate dehydrogenase (LDH) are tumor markers of small cell lung cancer (SCLC) which were reported to predict outcome of patients with SCLC. We previously reported that dipyridamole-modulated Tc-99m sestamibi (dipyridamole-MIBI) single photon emission computed tomography (SPECT) could predict the response to chemotherapy in SCLC patients. The purpose of this study was to compare dipyridamole-MIBI and pretreatment serum levels of NSE and LDH for the prediction of response to chemotherapy in SCLC. Twenty-eight SCLC patients underwent dipyridamole-MIBI SPECT 3 to 7 days before starting chemotherapy (80 mg/m2 etoposide and 80 mg/m2 cisplatin every 3 or 4 weeks for at lease two cycles). Serum levels of NSE and LDH were also measured at the same day of the imaging. Tomographic images before and after 0.84 mg/kg dipyridamole infusion were acquired 1 hour after injection of 370 (10 mCi) and 1,110 (30 mCi) MBq MIBI, respectively. The response to chemotherapy was grouped as specified as complete (CR), partial response (PR), no change (NC), and progressive disease (PD), according to the change in tumor size on chest roentgenography and CT. Patients showing CR and PR were classified as responders, and those who showed NC and PD were considered nonresponders. Among the 28 patients, 15 were responders (2 CR, 13 PR) and 13 were nonresponders (11 NC, 2 PD). The change of tumor-to-normal lung ratio (T:NL) after infusion of dipyridamole was significantly higher in responders as compared with nonresponders (0.38 +/- 0.64 vs. -0.38 +/- 0.50, respectively, p = 0.002). However, pretreatment serum NSE and LDH levels did not correlate with the response to chemotherapy. Increase of T:NL after dipyridamole infusion was a strong negative predictor of chemotherapeutic response in SCLC patients, while NSE and LDH could not predict it.

Differential regulation of the stearoyl-CoA desaturase genes by thiazolidinediones in 3T3-L1 adipocytes

Two stearoyl-CoA desaturase (SCD) isoforms can be expressed during the differentiation of 3T3-L1 preadipocytes into adipocytes. Here we report on the effects of the peroxisome proliferator-activated receptor gamma ligand troglitazone (TRO) on scd1 and scd2 mRNA levels as determined by Northern blotting, on SCD protein expression as determined by Western blotting, and on total lipid composition as determined by GC during differentiation. In preadipocytes, scd1 mRNA and SCD protein were not detected, whereas scd2 mRNA was detected. These cells have high levels of palmitate (16:0), stearate (18:0), and monounsaturated oleate (Delta(9)-18:1) and low levels of monounsaturated palmitoleate (Delta(9)-16:1). In MDI (methylisobutylxanthine, dexamethasone, and insulin)-treated cells, scd1 mRNA and SCD protein were increased approximately 100-fold relative to preadipocyte levels, the scd2 mRNA level was increased 2-fold, Delta(9)-16:1 was increased approximately 20-fold, and 18:0 was decreased approximately 3-fold. In TRO-treated cells, the scd1 mRNA level was lower than that observed in preadipocytes, while the scd2 mRNA level was similar. TRO also decreased scd1 mRNA in primary adipocytes. The TRO-treated cells contained a Delta(9)-18:1 level typical of MDI-treated cells whereas, conversely, these cells also contained a low Delta(9)-16:1 level typical of preadipocytes. The implications of these correlations for the regulatory and enzymatic mechanism(s) used to establish and maintain lipid composition are discussed.

Diarylheptanoids with in vitro inducible nitric oxide synthesis inhibitory activity from Alnus hirsuta

Four diarylheptanoids were isolated from the leaf of Alnus hirsuta (Betulaceae) and have been assessed for nitric oxide (NO) production inhibitory effects in vitro. Oregonin (1) and hirsutanonol (2) were found to be potent inducible nitric oxide synthase (iNOS) inhibitors. Compounds 1 and 2 showed inhibition of NO synthesis in dose-dependent manners by murine macrophage-like RAW 264.7 cells stimulated with interferon-gamma (IFN-gamma) plus lipopolysaccharide (LPS). Their 50% inhibitory concentrations (IC50) were 3.8 and 14.3 microM, respectively. The inhibitory effects of these compounds on NO synthesis were due to suppression of iNOS mRNA expression as determined by Northern blotting.

Photocatalytic sensor for chemical oxygen demand determination based on oxygen electrode

The construction and performance evaluation of a novel Chemical Oxygen Demand (COD) sensor is described. The sensor measures, using an oxygen electrode, a decrease of dissolved oxygen of a given sample resulting from photocatalytic oxidation of the organic compounds therein. As the photocatalyst, titanium dioxide (TiO2) fine particles adsorbed on a translucent poly(tetrafluoroethylene) (PTFE) membrane was used. The oxygen electrode with the membrane attached on its tip was used as the sensor probe. The operation characteristics of the sensor are demonstrated using an artificial wastewater and real water samples from lakes in Japan. This method is considered to be reliable, in that the observed parameter is close to the theoretical definition of chemical oxygen demand (COD), the amount of oxygen consumed for oxidation of organic compounds.

Algorithm for diagnosis and treatment of erectile dysfunction in the era of sildenafil citrate

Since Viagra (sildenafil citrate) was released as a pharmaceutical agent for the treatment of erectile dysfunction, it has had a big impact on the work undertaken in our practice. I herewith present an algorithm for the diagnosis and treatment of erectile dysfunction in the era of sildenafil citrate.

In search of selective P2 receptor ligands: interaction of dihydropyridine derivatives at recombinant rat P2X(2) receptors

1,4-Dihydropyridines are regarded as privileged structures for drug design, i.e. they tend to bind to a wide variety of receptor sites. We have shown that upon appropriate manipulation of the substituent groups on a 1,4-dihydropyridine template, high affinity and selectivity for the A(3) subtype of adenosine receptors ('P1 receptors') may be attained. In the present study we have begun to extend this approach to P2 receptors which are activated by ATP and other nucleotides. Nicardipine, a representative dihydropyridine, used otherwise as an L-type calcium channel blocker, was shown to be an antagonist at recombinant rat P2X(2) (IC(50)=25 microM) and P2X(4) (IC(50) approximately 220 microM) receptors expressed in Xenopus oocytes. Thus, this class of compounds represents a suitable lead for enhancement of affinity through chemical synthesis. In an attempt to modify the 1,4-dihydropyridine structure with a predicted P2 receptor recognition moiety, we have replaced one of the ester groups with a negatively charged phosphonate group. Several 4-phenyl-5-phosphonato-1,4-dihydropyridine derivatives, MRS 2154 (2, 6-dimethyl), MRS 2155 (6-methyl-2-phenyl), and MRS 2156 (2-methyl-6-phenyl), were synthesized through three component condensation reactions. These derivatives were not pure antagonists of the effects of ATP at P2X(2) receptors, rather were either inactive (MRS 2156) or potentiated the effects of ATP in a concentration-dependent manner (MRS 2154 in the 0.3-10 microM range and MRS 2155 at >1 microM). Antagonism of the effects of ATP at P2X(2) receptor superimposed on the potentiation was also observed at >10 microM (MRS 2154) or 0.3-1 microM (MRS 2155). Thus, while a conventional dihydropyridine, nicardipine, was found to antagonize rat P2X(2) receptors ninefold more potently than P2X(4) receptors, the effects of novel, anionic 5-phosphonate analogues at the receptor were more complex.

Polyphasic assignment of an aromatic-degrading Pseudomonas sp., strain DJ77, in the genus Sphingomonas as Sphingomonas chungbukensis sp. nov

Pseudomonas sp. strain DJ77, which was described as an aromatic-degrading bacterium, was investigated to clarify its taxonomic position. Phylogenetic analysis based on 16S rDNA sequences indicated that the strain belonged to the genus Sphingomonas and formed a monophyletic clade with the type strains of Sphingomonas chlorophenolica, Sphingomonas herbicidovorans and Sphingomonas yanoikuyae with sequence similarity values of 98.1, 96.1 and 95.6%, respectively. Genomic relatedness based on DNA-DNA hybridization of strain DJ77 to these strains is 7-14%. Strain DJ77 contained ubiquinone 10 as the main respiratory quinone, and the G+C content of DNA was 63 mol%. The organism contained octadecenoic acid (67%) as major cellular fatty acid. Strain DJ77 can be readily differentiated from representative members of the genus Sphingomonas using a battery of biochemical tests. On the basis of polyphasic evidence, it is proposed that strain DJ77, previously known as Pseudomonas sp., be reclassified in the genus Sphingomonas as Sphingomonas chungbukensis sp. nov. The type strain is strain DJ77T (= KCTC 2955T = IMSNU 11152T).

Cyclic adenosine monophosphate inhibits quinolone alkaloid evocarpine-induced apoptosis via activation of protein kinase A in human leukaemic HL-60 cells

Evocarpine, an isoquinolone alkaloid isolated from the fruit of Evodia rutaecarpa, was found to induce apoptotic cell death in promyelocytic leukaemia HL-60 cells in dose- and time-dependent manners. We investigated the involvement of protein kinase A during the evocarpine-induced apoptotic cell death. Evocarpine-induced apoptosis was markedly inhibited by treatment of the cells with dibutyryl-cyclic adenosine monophosphate. Similar results were obtained with other commonly used cyclic adenosine monophosphate analogues, chlorophenylthio-cyclic adenosine monophosphate and the intracellular cyclic adenosine monophosphate-elevating agent, forskolin. In contrast, pretreatment of HL-60 cells with KT5720, an inhibitor of cyclic adenosine monophosphate-dependent protein kinase A, abrogated the protective effects of cyclic adenosine monophosphate analogues and forskolin on evocrpine-induced apoptosis. These findings suggest that cyclic adenosine monophosphate-dependent activation of protein kinase A plays a crucial role in protecting HL-60 cells from the evocarpine-induced apoptotic cell death.

A case of Cushing's syndrome in ACTH-secreting mediastinal paraganglioma

Paragangliomas are unusual neuroendocrine cell tumors arising from paraganglia, of which ACTH-secreting cases in the mediastinum are extremely rare. A 51-year-old woman was admitted for generalized edema and weakness which began 5 months ago. Chest X-ray and CT scan revealed a tumor mass in the anterior mediastinum. The plasma cortisol and ACTH levels were very high. Other sources secreting ACTH, except mediastinal mass, were not found. Surgical excision of mediastinal mass and left supraclavicular lymph node was performed. The postoperative microscopic finding and immunohistochemical staining revealed organoid tumor cell nests (zellballen) and S-100 protein positive sustentacular cells which are characteristics of paraganglioma. This was thus a case of Cushing's syndrome resulting from ectopic ACTH production in anterior mediastinal paraganglioma.