Assessment of mitral annulus velocity by Doppler tissue imaging in the evaluation of left ventricular diastolic function

OBJECTIVES

This study assessed the clinical utility of mitral annulus velocity in the evaluation of left ventricular diastolic function.

BACKGROUND

Mitral inflow velocity recorded by Doppler echocardiography has been widely used to evaluate left ventricular diastolic function but is affected by other factors. The mitral annulus velocity profile during diastole may provide additional information about left ventricular diastolic function.

METHODS

Mitral annulus velocity during diastole was measured by Doppler tissue imaging (DTI) 1) in 59 normal volunteers (group 1); 2) in 20 patients with a relaxation abnormality as assessed by Doppler mitral inflow variables (group 2) at baseline and after saline loading; 3) in 11 patients (group 3) with normal diastolic function before and after intravenous nitroglycerin infusion; and 4) in 38 consecutive patients (group 4) undergoing cardiac catheterization in whom mitral inflow velocity and tau as well as mitral annulus velocity were measured simultaneously.

RESULTS

In group 1, mean +/- SD peak early and late diastolic mitral annulus velocity was 10.0 +/- 1.3 and 9.5 +/- 1.5 cm/s, respectively. In group 2, mitral inflow velocity profile changed toward the pseudonormalization pattern with saline loading (deceleration time 311 +/- 84 ms before to 216 +/- 40 ms after intervention, p < 0.001), whereas peak early diastolic mitral annulus velocity did not change significantly (5.3 +/- 1.2 cm/s to 5.7 +/- 1.4 cm/s, p = NS). In group 3, despite a significant change in mitral inflow velocity profile after nitroglycerin, peak early diastolic mitral annulus velocity did not change significantly (9.5 +/- 2.2 cm/s to 9.2 +/- 1.7 cm/s, p = NS). In group 4, peak early diastolic mitral annulus velocity (r = -0.56, p < 0.01) and the early/late ratio (r = -0.46, p < 0.01) correlated with tau. When the combination of normal mitral inflow variables with prolonged tau (> or = 50 ms) was classified as pseudonormalization, peak early diastolic mitral annulus velocity < 8.5 cm/s and the early/late ratio < 1 could identify the pseudonormalization with a sensitivity of 88% and specificity of 67%.

CONCLUSIONS

Mitral annulus velocity determined by DTI is a relatively preload-independent variable in evaluating diastolic function.

Temperature-guided radiofrequency catheter ablation of accessory pathway

OBJECTIVES

This study was performed to evaluate the usefulness of temperature-guided radiofrequency catheter ablation for the elimination of accessory pathway conduction in patients with Wolff-Parkinson-White syndrome.

METHODS

Temperature-guided radiofrequency catheter ablation was attempted in 138 patients with 144 accessory pathways (88 pathways along the left free wall, 5 in the anteroseptal region, 2 in the midseptal region, 19 in the posteroseptal region and 30 along the right free wall). The energy source was a HAT 200S which regulated the power automatically to the set temperature of 70 degrees C. Radiofrequency current was delivered through a thermocatheter to the atrial or ventricular side of mitral or tricuspid annulus.

RESULTS

Accessory pathway conduction was eliminated in 130 of 144 pathways (90.3%). The mean power outputs of the successful ablations at the atrial side of the annulus were higher than those at the ventricular side (34.0 +/- 8.9W versus 20.0 +/- 7.6W, p < 0.01), but the maximum temperatures were lower at the atrial side of the annulus than those at the ventricular side (66.4 +/- 14.0 degrees C versus 77.2 +/- 6.4 degrees C, p < 0.01). There were 3 non-fatal complications (2.1%), 2 patients with hemopericardium and 1 with femoral artery thrombus, during or after ablation procedures. Recurrences of AV re-entrant tachycardia or delta wave on the electrocardiogram occurred in 4 patients (2.8%) who had successful second procedures. There were no late complications during a mean follow-up period of 41 +/- 25 months (range, 3 to 55).

CONCLUSION

We conclude that 1) temperature-guided radiofrequency catheter ablation can be performed reliably and safely in eliminating accessory pathway conduction in patients with WPW syndrome, and 2) temperature monitoring and adjustment of the power to the set temperature during ablation would be useful for the avoidance of impedance rises and coagulum formation.

Natural occurrence of trichothecenes and zearalenone in Korean and imported beers

In order to survey the natural occurrence of Fusarium mycotoxins including deoxynivalenol (DON), nivalenol (NIV), and zearalenone (ZEN) in beers consumed in Korea, a total of 54 extracts of Korean and imported beers were derivatized with heptafluorobutyric anhydride and analysed by gas chromatography-mass spectrometry with selected ion monitoring mode. DON was detected in 14 samples (26%) and NIV was detected in 43 samples (80%). ZEN was not detected in any of the samples tested. The incidence of DON was 19% for Korean beers and 50% for imported beers, whereas the incidence of NIV was 85% for Korean beers and 58% for imported beers. This is the first report that the beers consumed in Korea are contaminated with DON and NIV.

The sensing of plant signal molecules by Agrobacterium: genetic evidence for direct recognition of phenolic inducers by the VirA protein

The virulence (vir) genes of Agrobacterium tumefaciens are induced by low-molecular-weight phenolic compounds and monosaccharides through a two-component regulatory system consisting of the VirA and VirG proteins. Although it is clear that the monosaccharides require binding to a periplasmic binding protein before they can interact with the sensor VirA protein, it is not certain whether the phenolic compounds also interact with a binding protein or directly interact with the sensor protein. To shed light on this question, we tested the vir-inducing abilities of several different phenolic compounds using two wild-type strains of A. tumefaciens, KU12 and A6. We found that several compounds such as 4-hydroxyacetophone and p-coumaric acid induced the vir of KU12, but not A6. On the other hand, acetosyringone and several other phenolic compounds induced the vir of A6, but not KU12. By transferring different Ti plasmids into isogenic chromosomal backgrounds, we showed that the phenolic sensing determinant is associated with the Ti plasmid. Subcloning of the Ti plasmid indicated that the virA locus determines which phenolic compounds can function as vir inducers. These results suggest that VirA directly senses the phenolic compounds for vir activation.

Isolation and characterization of two new type C fumonisins produced by Fusarium oxysporum

Two new fumonisins, hydroxylated fumonisin C1 (1) and fumonisin C3 (3), were isolated from wheat cultures of Fusarium oxysporum together with known fumonisin C1 (2) and C4 (4). Compound 1 is structurally similar to 2 except for the presence of an additional hydroxy group at C-3. Compound 3 is similar in structure to fumonisin B3 except that the C-1 terminal methyl group is missing.

2-amino-3-methylimidazo[4,5-f]quinoline-mediated immunosuppression involves inhibition of protein kinase C in murine splenocytes

The effects of the food-borne mutagenic and carcinogenic heterocyclic amine, 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), on the proliferation of murine spleen cells was examined. A significant and dose-related suppression of the proliferative response to concanavalin A (Con A) was observed by the treatment of IQ. IQ also decreased markedly the level of proliferative response induced by PMA and ionomycin and the IL-2 secretion by T cells. Treatment of PMA resulted in the recovery of IQ-induced suppression of IL-2 production, but the addition of ionomycin (Io) had no effect. IQ decreased PKC activity in both the membrane fraction and the cytosol fraction and inhibited the phosphorylation of MARCKS protein. These results suggest that the suppression of spleen cell proliferation induced by IQ might be associated with the inhibition of PKC activity and the subsequent IL-2 secretion of T cells.

Mutagenicity of cobalt and reactive oxygen producers

Oxidative stress has been implicated in carcinogenesis yet there are chemicals that produce oxidative stress that are not carcinogenic. Mutations are the inherited results of DNA damage and are critical events in carcinogenesis. The mutagenicity of oxidative stress induced by peroxide, paraquat and cobalt compounds was examined in transgenic gpt+ Chinese hamster cell lines (G12 and G10). These two cell lines are known to be more sensitive to mutagens such as X-rays and UV than their parental V-79 cells. In these studies, the mutagenic activity of cobalt chloride, a metal that induces oxidative stress but is not carcinogenic, was measured to be 7.7 times higher than the spontaneous mutant frequency in G12, but was only 1.5 to 2.5 times higher than spontaneous mutant frequency in G10 cells. The mutant frequency of cobalt sulfide was somewhat lower. Hydrogen peroxide was found to be only weakly mutagenic in G12 cells, and treatment of cells with a combination of hydrogen peroxide and cobalt did not alter the mutation frequency induced by cobalt sulfide alone. Paraquat did not elicit mutagenesis in either cell line. These results indicate that agents producing oxidative stress are not necessarily mutagenic and these results are discussed in the context of the oxidative stress produced by other carcinogens such as nickel compounds.

Pharmacology of the spinal adenosine receptor which mediates the antiallodynic action of intrathecal adenosine agonists

The effects of intrathecally delivered adenosine agonists on allodynia induced by L5/L6 spinal nerve ligation in rats with lumbar intrathecal catheters were examined. Tactile allodynia was assessed by measuring the threshold for evoking withdrawal of the lesioned hind paw with calibrated von Frey hairs. Intrathecal administration of the A1 adenosine selective agonist, N6-(2-phenylisopropyl)-adenosine R-(-)isomer (R-PIA), produced a dose-dependent (0.3-3 nmol; ED50 = 0.6 nmol) antiallodynic action and evoked a delayed motor weakness at a dosage of 30 nmol. Intrathecal administration of the A2 adenosine selective agonist, CGS 21680 {2-p-(2-carboxyethyl) phenethylamino-5'-N-ethylcarboxamido adenosine hydrochloride}, also produced a dose-dependent reduction in allodynia (2-40 nmol; ED50 = 15 nmol), but this effect was associated at 40 nmol after a short interval with prominent hind limb weakness. Intrathecal pretreatment with A1/A2 adenosine antagonists, caffeine (20 mumol) and 8-sulfophenyltheophylline (60 nmol), blocked antiallodynic actions of R-PIA (1 nmol) and CGS 21680 (40 nmol). Intrathecal pretreatment with the A1 adenosine-selective antagonist, 8-cyclopentyl-1,3-dimethylxanthine (3 nmol), blocked the antiallodynic effect of R-PIA (1 nmol), but even a dose as high as 10 nmol did not block the effect of CGS 21680 (40 nmol). The A2 adenosine-selective antagonist, 3, 7-dimethyl-1-propargylxanthine (3 nmol), prevented the antiallodynic effects of R-PIA (1 nmol) and CGS 21680 (40 nmol). Pretreatment with caffeine (20 mumol), 8-sulfophenyltheophylline (60 nmol) and 3,7-dimethyl-1-propargylxanthine (3 nmol) prevented the motor dysfunction induced by R-PIA (30 nmol) and CGS 21680 (40 nmol), but 8-cyclopentyl-1,3-dimethylxanthine (3 or 10 nmol) did not. Based on these effects, we hypothesize that the antiallodynic effects are mediated through the activation of spinal A1 adenosine receptors and motor dysfunction effects are mediated through A2 adenosine receptors.

No intermolecular interaction between the large hepatitis delta antigens is required for the secretion with hepatitis B surface antigen: a model of empty HDV particle

The large delta antigen (LDAg) of hepatitis D virus (HDV), which is similar to the small delta antigen (SDAg), except it has 19 additional amino acids and an isoprenylation signal at the C-terminus, is crucial for interacting with hepatitis B surface antigen (HBsAg) to form a mature virion of HDV. Previous studies indicated that the LDAg alone, but not SDAg, can interact with HBsAg to form an empty particle. However, no evidence yet shows whether the intermolecular interaction of LDAg is necessary for forming an empty HDV particle. By cotransfection of plasmids encoding deletion or isoprenylation-negative mutants of LDAg with a plasmid encoding HBsAg into human hepatoma cells, we demonstrated that (i) the isoprenylation-negative LDAg cannot be secreted, (ii) the coiled-coil domain-deleted LDAg retains the secretion capability, (iii) the isoprenylation-negative LDAg can neither cosecrete with isoprenylation-positive LDAg nor suppress its secretion, and (iv) an intermolecular interaction between LDAgs is unlikely required for secretion. A hypothetical model of empty HDV particle containing HBsAg with isoprenylated LDAgs, which are probably present in a singular form, was then proposed.

Suppression of alcohol intake after administration of the Chinese herbal medicine, NPI-028, and its derivatives

The Chinese herbal medicine, NPI-028, has been used for centuries in China to counteract alcohol intoxication. The present study used a number of different experimental conditions to determine whether NPI-028 and its derivatives might selectively influence alcohol intake in rodents that naturally exhibit high alcohol intakes. It was determined that intraperitoneal (i.p.) injections of NPI-028 (0.5, 0.75, and 1.0 g/kg) suppressed alcohol intake by up to 30% in both alcohol-preferring P and Fawn-Hooded (FH) rats during a continuous access schedule. These injections did not significantly affect food or water intakes, nor did the highest dose of NPI-028 (1 g/kg) alter blood ethanol levels after an i.p. injection of 2.5 g/kg of ethanol. In P rats, it was found that NPI-028 was orally active with the dose of 1.5 g/kg having a greater effect on ethanol intake than the 1.0 g/kg dose; once again, food and water intakes were not significantly altered. In FH rats maintained on a limited access schedule (1 hr/day), alcohol intake was completely abolished by 1.5 g/kg of NPI-028. Chronic i.p. administration of NPI-028 (0.75 g/kg) for four consecutive days in FH rats maintained on a continuous access schedule did not lead to any diminution of its alcohol-suppressant effects. Thus, NPI-028 has significant effects on alcohol intake without much effect on water and food intake, and tolerance does not readily develop to these effects. The i.p. administration of a partially purified extract (NPI-031) of NPI-028, obtained by countercurrent chromatography, also dose-dependently suppressed ethanol intake in FH rats, but the highest dose 200 mg/kg) also significantly decreased food intake. Finally, the i.p. administration of puerarin (NPI-31G), an isoflavone isolated from NPI-031 by countercurrent chromatography, significantly reduced ethanol intake in FH rats without affecting food or water intake. Therefore, NPI-028 and one of its pure components, NPI-031G, selectively reduced ethanol intake in alcohol-preferring rats.

Genetic evidence for direct sensing of phenolic compounds by the VirA protein of Agrobacterium tumefaciens

The virulence (vir) genes of Agrobacterium tumefaciens are induced by low-molecular-weight phenolic compounds and monosaccharides through a two-component regulatory system consisting of the VirA and VirG proteins. However, it is not clear how the phenolic compounds are sensed by the VirA/VirG system. We tested the vir-inducing abilities of 15 different phenolic compounds using four wild-type strains of A. tumefaciens--KU12, C58, A6, and Bo542. We analyzed the relationship between structures of the phenolic compounds and levels of vir gene expression in these strains. In strain KU12, vir genes were not induced by phenolic compounds containing 4'-hydroxy, 3'-methoxy, and 5'-methoxy groups, such as acetosyringone, which strongly induced vir genes of the other three strains. On the other hand, vir genes of strain KU12 were induced by phenolic compounds containing only a 4'-hydroxy group, such as 4-hydroxyacetophenone, which did not induce vir genes of the other three strains. The vir genes of strains KU12, A6, and Bo542 were all induced by phenolic compounds containing 4'-hydroxy and 3'-methoxy groups, such as acetovanillone. By transferring different Ti plasmids into isogenic chromosomal backgrounds, we showed that the phenolic-sensing determinant is associated with Ti plasmid. Subcloning of Ti plasmid indicates that the virA locus determines which phenolic compounds can function as vir gene inducers. These results suggest that the VirA protein directly senses the phenolic compounds for vir gene activation.

Attenuation of alcohol intake by ibogaine in three strains of alcohol-preferring rats

Alcohol-preferring (P), Fawn-Hooded (FH) and alcohol-accepting (AA) rats were injected intraperitoneally (IP) or subcutaneously (SC) with different doses (10, 30, and 60 mg/kg) of Ibogaine or vehicle. In a separate experiment, FH rats were administered intragastrically (IG) with either 60 mg/kg of Ibogaine or vehicle for 5 days. In addition, the effects of Ibogaine on blood alcohol concentrations were measured. Our data show that, contrary to the SC administration of Ibogaine, IP administration of the agent significantly and dose-dependently reduced alcohol intake in these rats. Subchronic IG administration of 60 mg/kg of Ibogaine into FH rats significantly reduced alcohol intake without the development of tolerance or a significant effect on food or water intake. A single IP injection of 60 mg/kg Ibogaine into FH rats did not affect the blood alcohol levels. These results show that Ibogaine when injected IP or IG, but not SC, can significantly reduce alcohol intake without an effect on blood alcohol concentrations or food intake. These findings may suggest the involvement of Ibogaine's metabolite(s) in reducing alcohol intake. Although the neuronal mechanism(s) of action of Ibogaine on the regulation of alcohol intake is not fully understood, it is speculated that Ibogaine or its metabolite(s) exerts its attenuating effect on alcohol intake by modulating neurotransmitters/neuromodulators proposed to be involved in regulation of alcohol consumption.

Systemic and supraspinal, but not spinal, opiates suppress allodynia in a rat neuropathic pain model

The effects of intraperitoneal (I.P.), intracerebroventricular (ICV) and intrathecal (IT) opiates were studied in the rat neuropathic pain model of Kim and Chung. Dose dependent reduction of allodynia was observed after I.P. and ICV morphine, but not after IT morphine, IT or ICV c[D-pen2 D-pen5]enkephalin (DPDPE) (delta agonist), or IT or ICV U50488H (kappa agonist). The effects of ICV morphine were blocked by I.P. naloxone, but not by IT methysergide, phentolamine or 8-sulfophenyltheophylline. Catalepsy (immobility) was observed after IT, ICV and IT morphine but this was not reliably associated with a reduction of allodynia. I.P. and ICV morphine may thus reduce tactile allodynia via supraspinal, but not spinal, mu opioid receptors.

AL072, a novel anti-Legionella antibiotic produced by Streptomyces sp

AL072 is a potent anti-Legionella antibiotic produced by Streptomyces strain AL91. The compound was isolated from the fermentation broth with 1 volume of isopropyl alcohol, followed by an ethyl acetate extraction and subsequent concentration under reduced pressure. Purification was performed on an octadecyl silica gel column followed by preparative HPLC. AL072 purified as mentioned above showed extremely specific activity only towards Legionella pneumophila. No antibacterial activity against any other bacteria tested was demonstrable. Its molecular weight was determined by FAB-MS (m/z 648) and the compound was identified as a novel 1,3-diacyl glycerol with the molecular formula C41H76O5. One of the two acyl groups is linoleyl and the other is 3,5-dimethyl octadecanoyl.

Evolution of left atrial thrombus with anticoagulant therapy-follow-up by transesophageal echocardiography

OBJECTIVES

Atrial fibrillation is an important risk factor for systemic embolism. A number of clinical studies demonstrated the beneficial effect of anticoagulant therapy for the prevention of embolism. But there has been no study on the fate of left atrial thrombus demonstrated by transesophageal echocardiography in the course of anticoagulation therapy.

METHODS

Thirteen patients, demonstrated to have left atrial thrombus by transesophageal echocardiography were followed with anticoagulation therapy. Repeated transesophageal echocardiography was done 15 months after 1st study.

RESULTS

Among 9 patients with adequate anticoagulation effect (INR > 2.0), left atrial thrombus disappeared in 3 patients. The size of thrombus decreased from 2.2 +/- 0.8cm to 0.9 +/- 1.0cm (p < 0.05 by paired Student's t-test).

CONCLUSIONS

Left atrial thrombus could dissolve or decrease in size with adequate anticoagulation.

Carcinogenic nickel silences gene expression by chromatin condensation and DNA methylation: a new model for epigenetic carcinogens

A transgenic gpt+ Chinese hamster cell line (G12) was found to be susceptible to carcinogenic nickel-induced inactivation of gpt expression without mutagenesis or deletion of the transgene. Many nickel-induced 6-thioguanine-resistant variants spontaneously reverted to actively express gpt, as indicated by both reversion assays and direct enzyme measurements. Since reversion was enhanced in many of the nickel-induced variant cell lines following 24-h treatment with the demethylating agent 5-azacytidine, the involvement of DNA methylation in silencing gpt expression was suspected. This was confirmed by demonstrations of increased DNA methylation, as well as by evidence indicating condensed chromatin and heterochromatinization of the gpt integration site in 6-thioguanine-resistant cells. Upon reversion to active gpt expression, DNA methylation and condensation are lost. We propose that DNA condensation and methylation result in heterochromatinization of the gpt sequence with subsequent inheritance of the now silenced gene. This mechanism is supported by direct evidence showing that acute nickel treatment of cultured cells, and of isolated nuclei in vitro, can indeed facilitate gpt sequence-specific chromatin condensation. Epigenetic mechanisms have been implicated in the actions of some nonmutagenic carcinogens, and DNA methylation changes are now known to be important in carcinogenesis. This paper further supports the emerging theory that nickel is a human carcinogen that can alter gene expression by enhanced DNA methylation and compaction, rather than by mutagenic mechanisms.

The aetiology of postmenopausal bleeding--a study of 163 consecutive cases in Singapore

OBJECTIVE

To study the aetiology and pattern of Postmenopausal Bleeding (PMB) in the local population.

DESIGN

A retrospective study

SUBJECTS

163 consecutive patients who presented with postmenopausal bleeding (PMB) SETTING: Kandang Kerbau Hospital, Singapore

RESULTS

Malignant causes were found in 42 (25.7%) patients. Cervical carcinoma was the most common malignancy (12.9% of the patients) followed by endometrial carcinoma (11%). Important benign causes are cervicitis (12.9%), atrophic vaginitis (12.3%) and cervical polyp (6.7%). Other benign causes include endometrial hyperplasia (3.1%), urethral caruncle (2.5%) and estrogen replacement therapy (1.8%).

CONCLUSION

PMB is a symptom of varied aetiologies. The associated incidence of malignancy is high and a thorough diagnostic evaluation is mandatory.

Structure-activity studies of 2,3,4,4a,5,9b-hexahydroindeno[1,2-c]pyridines as antispermatogenic agents for male contraception

Analogs of (4aRS,5SR,9bRS)-2-ethyl-2,3,4,4a,5,9b-hexahydro-7-meth yl-5-p- tolyl-1H-indeno[1,2-c]pyridine (Sandoz 20-438, 10a; R1 = ethyl, R2 = R3 = methyl, R4 = H) have been synthesized and tested in mice for their ability to reduce testes weight and disrupt spermatogenesis. The activity was strongly dependent on stereoisomerism and chirality, consistent with a mechanism of action involving interaction with a specific macromolecule. It was affected by changes in the nitrogen substituent and most strikingly by changes in the p-substituent of the 5-aryl ring. A hydrogen, fluorine, hydroxy, or methoxy substituent led to loss of activity, whereas methyl (Sandoz 20-438, 10a), carboxylate (RTI-4587-054, 10k; R1 = ethyl, R2 = methyl, R3 = COOH, R4 = H), ester (RTI-4587-056, 12b; R1 = ethyl, R2 = methyl, R3 = COOMe, R4 = H), formyl (RTI-4587-030, 12i; R1 = ethyl, R2 = methyl, R3 = CHO, R4 = H), or hydroxymethyl (RTI-4587-055, 12g; R1 = ethyl, R2 = methyl, R3 = CH2OH, R4 = H) groups resulted in antispermatogenic compounds. Methyl ester 12b was an effective antifertility agent, without apparent effects on mating, when given orally to male mice at 7-15 mg/kg daily for 35 days. Further evaluation of these compounds as male contraceptive agents and probes for study of spermatogenesis appears warranted.

Analysis of drug interaction between intrathecal clonidine and MK-801 in peripheral neuropathic pain rat model

BACKGROUND

Spinally delivered alpha 2-adrenoceptor agonists and N-methyl-D-aspartate antagonists each have been shown to have actions attenuating the hyperesthesia in rat models of nerve injury pain. Using a fixed-dose analysis and an isobolographic paradigm, the spinal interaction between the alpha 2-adrenoceptor agonist clonidine and the N-methyl-D-aspartate antagonist MK-801 is characterized in a rat model of nerve injury-induced tactile hyperesthesia.

METHODS

Male Sprague Dawley rats were anesthetized with halothane, and the left L5 and L6 spinal nerves were ligated (Chung model). After 7-10 days' recovery, a Polyethylene tubing catheter was implanted into the lumbar intrathecal space. After recovery from catheter implantations (5-7 days), intrathecal dose-response curves were established for the antihyperesthesia effects of clonidine (3, 6, 10, and 20 micrograms) and MK-801 (1, 3, 10, and 20 micrograms) alone to obtain the ED50 for each agent. In separate studies, three doses of clonidine (1, 3, and 10 micrograms) were injected mixed with one dose of MK-801 (1 microgram) for fixed-dose analysis, and three doses of the two agents (2, 6, and 20 micrograms) were injected jointly in a fraction of the dose ratio 1:1 for isobolographic analysis. Thresholds for left hind paw withdrawal to von Frey hair application were assessed.

RESULTS

Rats with nerve ligation showed a reliable tactile hyperesthesia (mechanical threshold 1-3 g vs. normal > 15 g). Intrathecal clonidine and MK-801 alone produced dose-dependent reductions of tactile hyperesthesia: ED50 9 micrograms and 10 micrograms, respectively. With the fixed-dose analysis, the log dose-response curves showed a left shift that considerably exceeds the theoretical curve made by a simple sum of the effects of clonidine alone and with MK-801 (1 microgram). With the isobolographic analysis, the combination ED50 was found to be statistically less than the theoretical additive dose combination. Intrathecal atipamezole, an alpha 2 antagonist, reversed the effects of clonidine and the clonidine/MK-801 mixture but not MK-801 alone. The side effect of clonidine was sedation and urination and that of MK-801 was motor weakness at doses above 10 micrograms. These effects were considerably less severe in rats after equiactive doses in the combination group.

CONCLUSIONS

The neuropathic pain is mediated by low-threshold mechanoreceptors, sympathetically dependent, and sensitive to both alpha 2 agonists and N-methyl-D-aspartate antagonists. Intrathecal clonidine may act to diminish sympathetic outflow, whereas MK-801 blocks the N-methyl-D-aspartate receptor that is associated with other spinal systems related to pain transmission mechanism. The two separate mechanisms may account for the powerful synergy observed in this study. Such combinations might be useful in neuropathic pain states to potentiate the antihyperpathic effects and to reduce the side effects of each agents.

Reversal of nerve ligation-induced allodynia by spinal alpha-2 adrenoceptor agonists

After nerve injury, a sympathetically dependent allodynia may be observed. Spinal alpha-2 agonists inhibit preganglionic neurons. The nature of the effect of alpha-2 agonists on allodynia induced by L5 and L6 nerve ligation (Chung model) was thus examined. Rats were implanted with spinal intrathecal catheters directed at the upper lumbar (L1-L2) or the lower cervical (C5-C6) spinal levels. After nerve injury, rats displayed a tactile allodynia (mean withdrawal thresholds, < 2.3 g). Lumbar intrathecal injection of alpha-2, but not alpha-1 or an opiate agonist, resulted in a dose-dependent reversal of the allodynia, with the ordering of activity (ED50 in micrograms in parentheses) being dexmedetomidine (0.9) > oxymetazoline (14) = guanfacine (17) = 5-bromo-6-(2-imidazolin-2-ylamino)quinoxaline (19) = 2-(2,6-diethylphenylamino)-2-imidazoline (21) = clonidine (22) > morphine (> 30) = methoxamine (> 30 micrograms). The effects of clonidine and 2-(2,6-diethylphenylamino)-2-imidazoline were reversed by the intrathecal injection of yohimbine. At equivalent doses, clonidine delivered systemically, i.c.v. by chronic ventricular guides, or at the level of the cervical spinal cord, produced substantially less antiallodynic action. These results jointly suggest that the sites of the antiallodynic action of spinal alpha-2 agonists are located at the level of the spinal preganglionic neurons and correspond to their ability to diminish preganglionic sympathetic outflow. The failure of morphine to exert an antiallodynic action reflects the fact that 1) opiates act presynaptically on small primary afferents and the allodynia is mediated by large afferent input and 2) opiates, unlike alpha-2 agonists do not have an effect on autonomic outflow.

Sambutoxin, a new mycotoxin produced by toxic Fusarium isolates obtained from rotted potato tubers

Ninety-nine isolates of Fusarium species were obtained from rotted potato tubers from various parts of Korea. Of these isolates, 80 were identified as Fusarium oxysporum, F. solani, or F. sambucinum. The isolates of these species were grown on autoclaved wheat grains and examined for toxicity in a rat-feeding test. A total of 8 of 57 F. oxysporum isolates, 3 of 14 F. solani isolates, and 5 of 9 F. sambucinum isolates caused the death of the rats. Of the 16 toxic isolates, 1 isolate of F. oxysporum produced a substantial amount of moniliformin, which could account for its toxicity. None of the other 15 isolates produced trichothecenes, moniliformin, fusarochromanone, fumonisin B1, or wortmannin. F. sambucinum PZF-4 produced an unknown toxin in wheat culture. This new toxin, given the trivial name sambutoxin, caused toxic effects in rats, including body weight loss, feed refusal, hemorrhage in the stomach and intestines, and, finally, death when rats were fed diets supplemented with 0.05 and 0.1% sambutoxin. The toxin was also toxic to chicken embryos, and the 50% lethal concentration was 29.6 micrograms per egg. Sambutoxin formed as white crystals that turned purple when combined with reagents such as sulfuric acid and p-anisaldehyde. It exhibited a green color immediately after treatment with potassium ferricyanide-ferric chloride. Its UV spectrum had absorption maxima at 213, 233, and 254 nm, and its infrared spectrum showed an amide group at 1,650 and 1,560 cm-1 and a hydroxy group at 3,185 cm-1. Mass spectrometry showed that the molecular weight of the toxin was 453 and the molecular formula was C28H39NO4.(ABSTRACT TRUNCATED AT 250 WORDS)

Preoperative diagnosis of angiomyolipoma of the liver

We experienced a case of surgically proven hepatic angiomyolipoma, a rare primary benign lipomatous tumor, which was preoperatively diagnosed by defining of its characteristic histologic components and benign radiologic nature with various imaging modalities. It was the first case that full radiologic evaluation was taken and internal vascular proliferation was defined by using dynamic bolus computed tomography (CT) prior to angiography.

Effects of D-ring substituents on antiprogestational (antagonist) and progestational (agonist) activity of 11 beta-aryl steroids

The discovery of antiprogestational steroids by the Roussel-Uclaf group not only was a major scientific advance but also opened the way to new methods of fertility control and new therapies for such conditions as cancer. RU486, the prototype of the series, is distinguished by a p-(N,N-dimethylaminophenyl) substituent at the 11 beta- position of the steroid framework, a 4,9-dien-3-one system and 17 beta-hydroxy-17 alpha-propynyl substituents. We examined the effect of varying the 17 alpha- substituent in 17 beta-hydroxy compounds analogous to RU486, the effect of introducing a progesterone side chain at C-17, and the effects of further substitution at C-17 alpha and C-16 alpha on the activity of these latter compounds. These studies indicate an important role for D-ring substituents in determining the balance of agonist/antagonist activity in this series. For example, 17 alpha-acetoxy-17 beta-acetyl substitution gave a potent antagonist, whereas 16 alpha-ethyl-17 beta-acetyl substitution resulted in a compound with potent progestational (agonist) activity. The compounds present opportunities for further interesting and useful biological investigations.

Problems and approaches in covalent attachment of peptides and proteins to inorganic surfaces for biosensor applications

Some of the fundamental problems in covalent attachment of peptides and proteins to putative biosensor surfaces are reviewed and specific approaches to these problems discussed. In addition, selected aspects of our recent work utilizing self-assembled monolayer (SAM) systems designed to react selectively with the thiol side chain of Cys in proteins are presented. Uniform attachment of a 21-amino acid peptide antigen through a single Cys residue with retention of biological function (antibody binding) has been attained. Further work with this system may lead to solutions for some of the problems which currently prevent the development of reliable biosensors for industrial and medical use.

Relation of pulmonary venous flow to mean left atrial pressure in mitral stenosis with sinus rhythm

To determine whether pulmonary venous flow measured by transesophageal Doppler echocardiography can be used to estimate mean left atrial pressure (LAP), we prospectively studied 12 consecutive patients with sinus rhythm undergoing percutaneous mitral balloon commissurotomy for their severe mitral stenosis (mitral valve area < 1.5 cm2). We correlated Doppler variables of pulmonary venous flow and the mean LAP measured by left atrial catheterization. Among the variables of the pulmonary venous flow, the systolic fraction (i.e., the systolic velocity-time integral expressed as a fraction of the sum of systolic and early diastolic velocity-time integral) correlated significantly with mean LAP (r = -0.71, p < 0.05) and mitral valve area (r = 0.64, p < 0.05). Peak velocity and velocity-time integral in systole also significantly correlated with mean LAP (r = -0.66, r = -0.67 respectively, p < 0.05). We conclude that the more severe the degree of mitral stenosis in patients with sinus rhythm, the less systolic pulmonary venous flow in severe mitral stenosis.

Natural occurrence of Fusarium mycotoxins (trichothecenes and zearalenone) in barley and corn in Korea

Barley is produced in four provinces, Chonbuk, Chonnam, Kyungbuk, and Kyungnam, and corn is mainly produced in the Kangwon province in Korea. The natural occurrence of Fusarium mycotoxins was surveyed in 39 barley and 46 corn samples from different areas. Five 8-ketotrichothecenes, namely deoxynivalenol (DON), nivalenol (NIV), 4-acetylnivalenol (4-ANIV), 3-acetyldeoxynivalenol (3-ADON), and 4,15-diacetylnivalenol (4,15-DANIV), and zearalenone (ZEA) were detected in barley. DON, NIV, and ZEA were the major contaminants in barley, with mean levels of 170, 1,011, and 287 ng/g, respectively. On the other hand, DON, 15-acetyldeoxynivalenol (15-ADON), NIV, 4-ANIV, 4,15-DANIV, and ZEA were detected in corn samples. DON and 15-ADON were the major contaminants in corn, with mean levels of 310 and 297 ng/g, respectively. The survey indicated that the natural occurrence of monoacetyl-DON and the ratios of NIV to DON in two cereals were different. In addition, this is the first report of the natural occurrence of 4,15-DANIV in cereals.

Coronary vasospasm, multiple coronary thrombosis, unstable angina and essential thrombocytosis

Rarely, essential thrombocythemia has led to coronary artery occlusion. Only one patient has been described, in whom coronary angiography demonstrated multiple coronary thrombosis. We report a case of coronary vasospasm, multiple coronary thrombosis involving right and left coronary artery and possibly leading to myocardial infarction and unstable angina pectoris in a woman with migraine, Raynaud's phenomenon, and essential thrombocytosis.

A gene for cytochrome c oxidase subunit II in duck mitochondrial DNA: structural features and sequence evolution

The gene encoding cytochrome c oxidase subunit II (COXII) was amplified by polymerase chain reaction (PCR) using mitochondrial DNAs (mtDNAs) isolated from two genera of domesticated ducks, Anas platyrhnchos and Cairina muschata, and their intergeneric and intrageneric hybrids as templates. Comparison of the nucleotide sequences from the two different duck lineages shows that they have approximately 91% homology. The nucleotide substitution pattern in the duck COXII gene reveals a high transition/transversion ratio (8.8:1.0) while 93.2% of the nucleotide substitutions are silent. The duck COXII, which uses GUG as the initiation codon, contains 228 amino acid residues. Comparison of the deduced COXII amino acid sequences in duck, chicken, Xenopus laevis, mouse, bovine and human reveals five highly conserved domains. The evolutionary conservation of the primary structure of COXII implies its functional importance.

Mutagenicity of soluble and insoluble nickel compounds at the gpt locus in G12 Chinese hamster cells

Nickel is an established human and animal carcinogen, but efforts to demonstrate its mutagenicity in a number of cell types have not been successful. In this report we describe the mutational response to nickel compounds in the G12 cell line, an hprt deficient V79 cell line containing a single copy of the E. coli gpt gene. This cell line has a low spontaneous background, making it suitable for assessment of mutagenic responses to environmental contaminants. When G12 cells were treated with insoluble particles of crystalline nickel sulfide < 5 microns in diameter, a strong, dose-dependent mutagenic response was observed up to 80 times the spontaneous background. Of 48 mutant gpt(-) clones isolated that were induced by insoluble nickel, all were capable of DNA amplification of the gpt sequences by polymerase chain reaction (PCR). The ability to produce full-length PCR products is an indication that large deletions of gene sequences have not occurred. When G12 cells were treated with soluble nickel sulfate, the mutational response was not significantly increased over the spontaneous background. This difference in mutagenic response reflects a large difference in the mutagenic potential of soluble and insoluble nickel compounds, which reflects the carcinogenic potential of these forms of nickel.

Natural occurrence of Fusarium mycotoxins of the 1990 barley crop in Korea

During the barley harvest in June 1990, there was a great deal of rainfall and high humidity in the southern part of Korea, and natural occurrence of Fusarium mycotoxins was suspected in barley samples. The samples of undergrade barley were obtained from four provinces and analysed for the presence of deoxynivalenol (DON) and nivalenol (NIV) by gas chromatography and zearalenone (ZEN) by high performance liquid chromatography. Of 37 samples, 33, 37 and 10 were positive for DON, NIV and ZEN, respectively. The husked barley contained 29-677 ng/g for DON, 114-1546 ng/g for NIV and 183-1416 ng/g for ZEN. The naked barley contained 38-645 ng/g for DON, 85-4569 ng/g for NIV and 40-1081 ng/g for ZEN. The average concentration of NIV in naked barley was higher than that in husked barley, but the average concentration of DON in husked barley was higher than that in naked barley. The survey indicates that the 1990 barley crop in Korea was heavily contaminated with Fusarium mycotoxins.

A conserved region in human and Chinese hamster X chromosomes can induce cellular senescence of nickel-transformed Chinese hamster cell lines

Cellular senescence is the genetically programmed cessation of cellular proliferation. We have recently mapped a putative senescence gene(s) on the X chromosome of Chinese hamster embryo (CHE) cells. In the present study, we have utilized microcell-mediated chromosome transfer (microcell fusion) to test whether: (i) the human X chromosome exhibits similar genetic potential to induce senescence and (ii) the deletion or inactivation of the X-linked senescence gene(s) in CHE cells is associated with nickel-induced immortalization. A normal CHE or human X chromosome was first introduced into mouse-cell hybrids, then transferred by microcell fusion into a nickel-transformed, immortal male CHE cell line (Ni-2/TGR) with an X deletion (Xq1). Microcell fusion of the normal CHE X chromosome into tumorigenic Ni-2/TGR cells yielded senescence of all X recipient clones. The normal human X chromosome induced dominant senescence of tumorigenic Ni-2/TGR cells in only 17% of the resulting microcell hybrids (14/81). Karyotypic analyses of 13 non-senescing human X chromosome-derived microcell hybrid clones revealed that none of these clones retained the complete X. A normal CHE X chromosome induced senescence of 75% of hybrids obtained with another immortal and tumorigenic nickel-transformed male CHE cell line (Ni-6/TGR), which exhibited no visible deletion of the X chromosome, while the normal human X chromosome, only induced senescence in 19% of these hybrids. Transfer of the normal CHE or human X chromosome into spontaneously transformed and tumorigenic cell lines, CHO/TGR or V79/TGR, had little or no effect on their growth. These data suggest that both human and CHE cells possess similar X-linked genetic activities that regulate the process of cellular senescence, and that in Chinese hamster cells nickel-induced immortalization but not that of CHO or V79 cells is associated with inactivation of an X-linked senescence gene.

Takayasu arteritis in Korea: Clinical and angiographic features

Clinical and angiographic features of Takayasu arteritis were investigated in 129 Korean patients. This disease affects females more frequently than males, in a ratio of 6.6 to 1. Of the total number of patients, 51 were in the third decade, 27 in the fourth decade, and 23 in the second decade. Common clinical symptoms were headache (60%), exertional dyspnea (42%), dizziness (36%), and malaise or weakness (34%). Takayasu arteritis affected the abdominal aorta (46%) and descending thoracic aorta (37%) more frequently than the ascending aorta (1%) and aortic arch (2%) According to Ueno's classification based on aortographic findings, the 129 patients were divided into type I (37), type II (25), and type III (67). Among the 48 patients who had coronary angiography, 11 (23%) showed coronary arterial involvement. Because the clinical features are determined by the extent and severity of the specific artery involved in the occlusive phase of the disease, total aortography including coronary angiography is very important in the initial evaluation of Takayasu arteritis.

Percutaneous mitral valvuloplasty in a mid-term pregnant woman with severe rheumatic mitral stenosis

A 28-year-old woman with severe mitral stenosis underwent percutaneous mitral valvuloplasty at 26 weeks' gestation. Balloon dilation using a double 18-18 mm balloon resulted in improvement in mean mitral pressure gradient (32 to 8 mmHg) and in calculated mitral valve area (0.9 to 2.4 cm2) without complications and any evidence of fetal distress during procedures with an estimated radiation exposure to the fetus of 0.13 rem. This procedure resulted in the disappearance of symptoms of congestive heart failure and allowed for normal full term spontaneous delivery of a 3.51 Kg boy without any complication.

A study on the isolation of aflatoxin-producing strains from agricultural products in Korea

In order to isolate aflatoxin-producing strains from agricultural products in the Youngnam district of Korea, rice, barley, unhulled barley, corn, soybean, Meju (soybean paste), peanut, and soil samples were collected from markets or homes. From the 347 samples, 280 strains of Aspergillus spp. were isolated. As a result of screening by thin layer chromatography (TLC), 29 strains showed fluorescent spot and four strains had the same Rf values as those of standard aflatoxins. The percentage of contamination of aflatoxin-producing strains was 1.4%. The four strains were classified as the Aspergillus flavus group by the examination of characteristics and morphology.

Successful management of mechanical complications following acute myocardial infarction--a case report

Rupture of the heart as a complication of myocardial infarction is one of the most common causes of in-hospital mortality. Rupture of the free wall of the ventricle or interventricular septum has a poor prognosis when treated conservatively. So, rupture of the heart after infarction requires prompt diagnosis and early surgical repair despite the high overall incidence of early operative mortality before hemodynamic deterioration and multiorgan failures develop. Rupture of the left ventricle results in pseudoaneurysm if the overlying pericardium adhers to the surface of the heart. Pseudoaneurysms which rarely develop after infarction, tend to rupture. Their presence alone is an indicator for operation because of the very poor prognosis following rupture. We experienced successful management of 2 rare complications after acute myocardial infarction: ventricular septal defect and pseudoaneurysm. The first patient was a 49-year-old man who had an apical septal defect. His electrocardiogram showed Q wave in leads V2-V6, II, III, and aVF but a coronary angiogram showed normal findings. He was successfully treated by patch closure of the septal defect. The second patient was a 65-year-old female who had false aneurysm of the left ventricle. She had neither chest pain nor abnormality on the electrocardiogram. A coronary angiogram showed complete occlusion of the distal circumflex artery. Under cardiopulmonary bypass, the neck of the aneurysmal sac was successfully closed with a prolene suture.

Mitral stenosis: evaluation with MR imaging after percutaneous balloon valvuloplasty

To evaluate the pathoanatomic findings of mitral valve stenosis and changes after percutaneous balloon valvuloplasty (PBV), magnetic resonance (MR) imaging was performed in 23 patients. The patients were imaged with a 2.0-T system within 1 week before and 3-10 days after PBV. The angle of the interatrial septum was measured on the transverse image to facilitate a successful transseptal puncture. On MR images, the mean transverse and anteroposterior diameters of the left atrium at the level of the aortic root in the ventricular diastolic phase decreased significantly after PBV. Areas of flow-related intraluminal signal intensity detected in the left atrial cavity of 17 patients (74%) before the procedure disappeared in 15 patients after the procedure. Other MR imaging findings after PBV were the disappearance of intraluminal signal intensity in the pulmonary artery, normal curvature of the interatrial and interventricular septa, and pericardial effusion as a complication. MR imaging was thought to provide useful information before and after PBV in patients with mitral stenosis.

Application of countercurrent chromatography/thermospray mass spectrometry for the identification of bioactive lignans from plant natural products

The versatility and resolving power of countercurrent chromatography (CCC) has been demonstrated with a newly developed analytical high-speed planet centrifuge system. Interfacing countercurrent chromatography with mass spectrometry (MS) provides a new analytical methodology that integrates the advantages of countercurrent chromatography with the low detection limit and identification capability of mass spectrometry. In this paper the capability of thermospray CCC/MS is demonstrated in identifying and validating the bioactive and structurally known lignans from a crude extract of Schisandra rubriflora Rhed et Wils, a traditional Chinese herbal medicine for treatment of hepatitis.

Improved high-speed counter-current chromatograph with three multilayer coils connected in series. II. Separation of various biological samples with a semi-preparative column

The semipreparative capability of the newly developed high-speed counter-current chromatograph equipped with a set of three multilayer coils has been demonstrated in separations of a variety of biological samples including triterpenoic acids, indole auxins, bacitracin, flavonoids and tetracycline derivatives, each with a suitable two-phase solvent system. The sample quantities ranging from 50 to 500 mg were efficiently separated within a few hours. The separation of tetracycline derivatives was remarkably improved by adding ammonium acetate to the solvent system.

Isoverrucarol production by Fusarium oxysporum CJS-12 isolated from corn

Isoverrucarol (3,15-dihydroxy-12,13-epoxy-trichothec-9-ene) was isolated and purified from wheat cultures of a toxic strain of Fusarium oxysporum CJS-12. The toxin was characterized by thin-layer chromatography, gas chromatography-mass spectrometry, and 1H and 13C nuclear magnetic resonance spectrometry. Isoverrucarol caused toxic effects in rats, including loss of appetite, bodily weakness, severe mucosae of the stomach, and death, when administered orally at 10 and 20 mg/kg of body weight. The toxin also caused a definite dermatitic reaction of epidermis and an edematic-necrotic response of the dermis.

Clinical and morphological features of hypertrophic cardiomyopathy in Korean patients

Thirty three cases of hypertrophic cardiomyopathy (HCMP) were reviewed to estimate the relative frequencies of the subtypes of HCMP and to clarify whether there is any racial difference in clinical and morphological features of HCMP. The diagnosis was made by echocardiography, cardiac catheterization and left ventriculography. Twenty four patients underwent coronary angiogram. Numbers of cases by the types of HCMP were 20 (61%) with asymmetrical septal hypertrophy (ASH), 11 (33%) with apical hypertrophy (APH) and 2 (6%) with midventricular hypertrophy (MVH). Mean ages of the patients with APH, ASH and MVH were 54, 46 and 31 years respectively, and the differences were statistically significant (p less than 0.05). The giant negative T wave on electrocardiogram was seen in 4 patients (20%) of ASH and 5 patients (45%) of APH. On echocardiogram mean ratio of interventricular septal to left ventricular posterior wall thickness was 1.9 in ASH, 1.2 in APH and 1.6 in MVH, and the differences were statistically significant (p less than 0.05). All patients with APH showed "spade of ace" deformity in left ventriculography. Coronary angiograms were normal in all patients who had the procedure. Our study showed high frequency of APH of which characteristics were similar to those of the Japanese type APH.

Cough syncope caused by sinus arrest in a patient with sick sinus syndrome

Cough syncope is a syndrome in which dizziness or syncope occurs after prolonged bouts of cough. This paper presents a case of 63-year-old man with recurrent dizziness and syncope. The 24-hour ambulatory electrocardiogram and intracardiac electrogram showed sinus node dysfunction with sinus arrest, both spontaneous and inducible by voluntary cough. Sinus arrest was sometimes associated with dizziness. A permanent VVI pacemaker was implanted and no further cough syncope has occurred. We suggest that sinus arrest may play a role as a mechanism of cough syncope in a patient with sick sinus syndrome.

Countercurrent chromatography meets MS

Interfacing countercurrent chromatography with thermospray mass spectrometry provides a new analytical tool for detecting nonvolatile, hydrophilic or thermally unstable bioactive natural products.

Preliminary applications of cross-axis synchronous flow-through coil planet centrifuge for large-scale preparative counter-current chromatography

The cross-axis synchronous flow-through coil planet centrifuge with a 20-cm revolutional radius and a total capacity of 1600 ml was successfully applied to preparative counter-current chromatography of various biological samples, which include sea buckthorn extract, steroid reaction mixture, indole plant hormones, and dinitrophenylamino acids. The present system offers advantages of stable balance of the centrifuge, a large column capacity, and high resolution.