Alteration of neuronal calcium homeostasis and excitotoxic vulnerability by chronic depolarization

Free intracellular Ca2+ concentration ([Ca2+]i, Ca2+ currents, and excitatory amino acid (EAA) currents were studied in spinal neurons cultured in low (4.5 mM) and high (25 mM) extracellular potassium. When challenged with lethal concentrations of N-methyl-D-aspartate (NMDA) or kainate, neurons cultured in 25 mM K+ exhibited markedly attenuated Ca2+ currents and [Ca2+]i responses, and survived the EAA challenge more readily than controls. Surprisingly, NMDA and Kainate currents remained comparable between neurons grown in high- and low K+. The disparity between the observed [Ca2+]i increases and EAA currents suggests that chronic depolarization induces a fundamental alteration in intracellular Ca2+ handling. This phenomenon may provide clues for the development of neuroprotective strategies against excitotoxin excess.

Expression of functional metabotropic and ionotropic glutamate receptors in baculovirus-infected insect cells

An ionotropic glutamate receptor of the kainate subtype (GluR6) and a G-protein coupled metabotropic glutamate receptor (mGluR1 alpha) were expressed and studied in two insect cell lines: sf9 cells from Spodoptera frugiperda and MG1 cells from Trichoplusia ni. Application of kainate to GluR6-infected MG1 cells produced kainate-activated currents. Glutamate activation of mGluR1 alpha in MG1- and sf9-infected cells caused rapid, transient increases in intracellular calcium levels. This effect was more pronounced in MG1 cells compared to sf9 cells. These results indicate that functional glutamate receptors can be expressed in the baculovirus system, and that MG1 cells may have several advantages over the widely used sf9 cells for studying the functional properties of receptors and channels.

Regulation of NMDA receptors in cultured hippocampal neurons by protein phosphatases 1 and 2A

Phosphorylation of glutamate receptors is probably an important mechanism for modulating excitatory transmission. However, there is little direct evidence to indicate which protein phosphatases can dephosphorylate glutamate or other ligand-gated channels, although it is known that protein phosphatases 1 and 2A play a major part in modulating voltage and second-messenger-gated channels. Here we report that in cultured hippocampal neurons, the N-methyl-D-aspartate (NMDA) receptor can be regulated by endogenous and exogenous serine/threonine protein phosphatases. Phosphatase inhibitors enhanced NMDA currents recorded using the perforated patch technique or in cell-attached patches, whereas protein phosphatases 1 or 2A decreased the open probability of these channels in inside-out patches.

Sensitivity of AMPA receptors to pentobarbital

The inhibitory effects of pentobarbital on various AMPA receptors expressed (GluR1, GluR3, GluR1/3, GluR1/2, and GluR2/3) in Xenopus oocytes were examined. Combinations of AMPA receptor subunits that included GluR2 demonstrated a much higher sensitivity to blockade by this barbiturate and the apparent co-operativity of the interaction of pentobarbital with the receptor was reduced. This evidence demonstrates that the GluR2 subunit alters the structure of AMPA receptors in such a way as to facilitate any interaction with this barbiturate.

A transmembrane model for an ionotropic glutamate receptor predicted on the basis of the location of asparagine-linked oligosaccharides

Several different models have been proposed for the transmembrane structure of receptors for the neurotransmitter L-glutamate. In this study, the sites of N-linked oligosaccharides on GluR6, a member of the kainate class of ionotropic glutamate receptors, were examined. Site-directed mutagenesis was utilized to alter the consensus sequence at three potential sites for N-linked glycosylation in the carboxyl-terminal half of the molecule. The presence of a carbohydrate substitution was monitored by shifts in the relative molecular weight of the mutant receptors on immunoblots. Molecular weight shifts were observed for the mutants N515Q and N720Q and for two companion mutants, T517A and T722A, which also eliminate the consensus sequence for N-linked glycosylation. No shift in molecular weight was observed in the the mutant N574Q. These results indicate that asparagines 515 and 720 are glycosylated and thus are likely located extracellularly. In immunocytochemical analyses of GluR6 expressed in baculovirus-infected cells, permeabilization with detergents was required for immunostaining with a carboxyl-terminal antibody, indicating that the carboxyl terminus is located intracellularly. Electrophysiological recordings of the mutant receptors expressed in human embryonic kidney cells demonstrated that the amplitudes of the kainate-activated currents mediated by the N574Q, N720Q, and the T722A mutants were not significantly different from currents mediated by wild type GluR6 receptors, while the currents mediated by the N515Q and T517A mutants were significantly depressed. Based on these findings, we propose a model for the transmembrane topology of GluR6.

Seroprevalence and associated risk factors of Helicobacter pylori infection in Taiwan

In order to estimate the seroprevalence and explore multiple risk factors associated with Helicobacter pylori infection among residents in Taiwan, a total of 823 subjects randomly selected from one metropolitan precinct and three townships were studied. Serum samples were tested for IgG antibodies against H. pylori by enzyme-linked immunosorbent assay using commercial kits. The overall seropositive rate was 54.4% with no gender difference (53.7% for males and 55.2% for females). There was a significant geographical variation with the highest seropositive rate (63.4%) in rural area where aborigines live, and where the age-adjusted stomach cancer mortality is highest and the lowest (40.5%) in urban area where Hakkas live, and where the stomach cancer mortality is lowest. There was also an increasing seropositive rate with age from 27.1% for children younger than 10 years old to 72.3% for adults aged more than 40 years old. Age-specific seroprevalence in Taiwan is higher than that in United States, France, Finland and Australia, and lower than that in Algeria, Ivory Coast and India. No association with H. pylori seropositivity was observed for drinking water source, toilet type, family income and educational level after adjusting for age and area. A dose-response relation between H. pylori seropositivity and sibship size was found. Upon further analysis of seroprevalence for children aged 16 or younger, a positive association was observed for birth order and current number of children in family; there was also an inverse association for current number of adults in family. The early childhood transmission among siblings seems an important determinant of H. pylori seropositivity in Taiwan.

Alveolar permeability enhancement by oleic acid and related fatty acids: evidence for a calcium-dependent mechanism

Pulmonary exposure to oleic acid (OA) is associated with permeability alterations and cellular damage; however, the exact relationship between these two effects has not been clearly established. Using cultured alveolar epithelial monolayers, we demonstrated that OA and some other fatty acids (< or = 50 microM) can induce permeability changes without detectable cellular damage. At higher concentrations, however, OA caused severe membrane damage and leakage to solute flux. The permeability enhancing effect of OA was observed with both the paracellular marker 3H-mannitol and the lipophilic transcellular indicator 14C-progesterone. While the effect of OA on transcellular permeability may be attributed to its known effect on membrane fluidity, the paracellular promoting effect of OA and its mechanism are not well established. We postulated that OA may increase paracellular permeability through a Ca(2+)-dependent tight junction mechanism. Using dual-excitation fluorescence microscopy, we demonstrated that OA can increase intracellular calcium, [Ca2+]i, in a dose-dependent manner. This effect was transient at low OA concentrations (< or = 50 microM) but became more pronounced and sustained at higher concentrations. Free hydroxyl and unsaturated groups were required for this activation since esterified OA (oleic methyl ester) and stearic acid (a saturated fatty acid with equal chain length) had much reduced effects on both the [Ca2+]i and the permeability alterations. Degree of unsaturation was unimportant since linolenic acid (18:3), linoleic acid (18:2), and OA (18:1) had similar and comparable effects on the two parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

p53 gene mutations in brain tumors in Taiwan

Mutations of the p53 gene were investigated in 116 surgically removed primary brain tumor tissues by PCR-SSCP analysis. The mutations did not follow a random distribution among the various different subtypes, but occurred in 21.0% (13/62) of astrocytomas, 13.0% (3/23) of oligodendrogliomas and 35% (7/20) 35% (7/20) of PNETs. No mutation was found in the ependymomas. The majority of mutations identified in this study were G:C to A:T or C:G to T:A transitions (56.0%, 14 of 25) and occurred most frequently (56.0%, 14 of 25) at sites of CpG dinucleotides. Interestingly, codon 158 is a new hot spot which occurred with a frequency of 16.0% (4 of 25) in the samples analyzed.

Modulation of AMPA/kainate receptors in cultured murine hippocampal neurones by protein kinase C

1. The patch clamp technique, together with intracellular perfusion of the catalytic fragment of protein kinase C (PKCM), was employed to investigate the role of this enzyme in the intracellular regulation of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)/kainate receptors in cultured hippocampal neurones. 2. The responses evoked by near-maximal concentrations of kainate (250 microM) and AMPA (100 microM) were potentiated by the introduction of PKCM, whilst co-application of the inhibitory peptide fragment PKCI(19-36) prevented this action. 3. Modulation of kainate responses by PKCM was dependent upon the concentration of agonist applied. Currents evoked by kainate were potentiated at concentrations above those which caused 50% of the maximal response (EC50) and depressed at lower concentrations. Furthermore, okadaic acid, a specific inhibitor of phosphatases 1 and 2A, had a similar effect upon concentration-response relationships when currents activated by kainate were recorded using the perforated patch technique. 4. In addition, the mean amplitude and/or time constant of decay of miniature excitatory synaptic currents (mediated by AMPA/kainate receptors) was increased by the intracellular injection of PKCM. 5. These observations suggest that the function of postsynaptic excitatory amino acid receptors can be modulated by the activity of PKC as well as by endogenous phosphatases. This regulation may contribute to some forms of synaptic plasticity within the central nervous system.

[Effects of puerarin on cat vascular smooth muscle in vitro]

Puerarin is an isoflavone compound isolated from Pueraria lobata (Wild). This study characterized the vascular action of puerarin in order to more clearly elucidate its pharmacological activities. Helically cut strips of cat femoral veins and renal arteries were suspended in an organ chamber filled with Krebs bicarbonate solution for measurement of isometric force development. In the cases of femoral veins and renal arteries isoproterenol (0.01 mumol.L-1 -0.1 mmol.L-1) caused relaxation of methoxamine-induced contraction (0.01 mmol.L-1) in a concentration-related manner. Puerarin (0.01-0.1 mmol.L-1) inhibited the relaxation response to isoproterenol in a concentration-response fashion. Propranolol (0.1-1 mumol.L-1) inhibited the isoproterenol-induced relaxation too. Puerarin (0.1mmol.L-1) did not alter the relaxation response to nitroglycerin (1 mumol.L-1). These results indicated that puerarin acted as a beta-adrenoreceptor antagonist in isolated arteries and veins.

Development of portal vein invasion and its outcome in hepatocellular carcinoma treated by transcatheter arterial chemo-embolization

Hepatocellular carcinoma (HCC) is one of the most common malignancies in the world. One serious complication is the invasion of the portal vein. To investigate the new invasion of the portal vein in HCC following treatment by transcatheter arterial chemo-embolization (TACE), 124 patients with HCC were screened by ultrasound, computed tomography and angiography. Fifteen patients were diagnosed with portal vein invasion (PVI) during the initial examination and were excluded from the study. Of the remaining 109 patients, 18 developed PVI. Fourteen were male and four were female. None of these 18 patients completely responded to TACE treatment and all were in recurrence. The median time for appearance of PVI after the first TACE was 212 days. The median interval between PVI and the last negative ultrasound examination was 100 days. Both were correlated with the degree of PVI. The only significant factor affecting the time until the appearance of PVI was the TACE treatment. After the development of PVI, eight patients continued with the TACE treatment, and three of these patients were also treated with portal vein local chemotherapy. The regression of PVI was observed in two patients. The median survival time after the discovery of PVI was 129 days. Factors affecting the survival time were performance state, Pugh classification, sex, the area of tumour invasion and continued treatment.

Increased sister chromatid exchange frequency in peripheral lymphocytes of nasopharyngeal carcinoma and cervical cancer patients

The specific aim of this study was to compare the frequency of sister chromatid exchange (SCE) in peripheral lymphocytes using it as a biomarker of integral exposures to carcinogens in 14 untreated newly-diagnosed nasopharyngeal carcinoma (NPC) patients, 16 untreated newly-diagnosed cervical cancer patients, and 30 healthy controls matched with patients on age, sex, cigarette smoking and alcohol drinking. Peripheral lymphocytes were cultured in RPMI 1640 medium containing 20% fetal calf serum and 6 microM phytohemagglutinin. After culture for 24 hours, 20 microM 5-bromo-2-deoxyuridine was added into the medium. Colcemid solution was further added after 70 hours. Harvested cells were stained with Hoesch 33258, illuminated, and restained with Giemsa. The SCE frequency was scored by two readers independently and blindly. The results showed a significantly increased SCE frequency in lymphocytes for NPC patients (mean +/- standard error = 14.7 +/- 1.7 SCEs/cell) compared with their matched controls (10.1 +/- 0.7 SCEs/cell) and for cervical cancer patients (12.0 +/- 0.9 SCEs/cell) compared with their matched controls (9.2 +/- 0.7 SCEs/cell). These results suggest that NPC and cervical cancer patients have a higher integral exposures to both viral and chemical carcinogens than matched controls.

[Changes in blood visco-elasticity in normal pregnancy and pregnancy induced hypertension]

The study was designed on blood visco-elasticity of normal pregnant and pregnancy induced hypertension (PIH) women. Visco-component (eta'), elastic-component (eta") and storage modulus (G') decreased significantly during the 1st trimester of pregnancy, but rose slowly in the 3rd trimester. eta' was the most significant and it revealed an inverse correlation with neonate birth weight. There were no changes of eta', eta" and G' in women with mild PIH, but they rose markedly in groups with moderate and severe PIH. In conclusion, abnormal blood viscosity and elasticity, i.e. an increase of RBC aggregation and/or a decrease of RBC deformability, may be an important abnormal hemorheological changes in PIH.

Hepatitis C virus infection as a risk factor for non-alcoholic liver cirrhosis in Taiwan

To assess whether hepatitis C virus infection was a risk factor for the development of non-alcoholic liver cirrhosis, antibody to hepatitis C virus (anti-HCV; detected by a second generation HCV enzyme immunoassay), hepatitis B surface antigen (HBsAg; detected by radioimmunoassay) were tested in 150 cirrhotics and 150 sex-matched and age-matched healthy controls. The prevalence of anti-HCV and HBsAg in cirrhotics was higher than in controls (22.0%, 73.3% vs. 2%, 18.7%; P = 0.001). The prevalence of anti-HCV in HBsAg-negative cirrhotics (45.0%) was higher than that in HBsAg-positive patients (13.6%; P = 0.001). Both the anti-HCV and carriage of HBsAg were associated significantly with liver cirrhosis, showing odds ratio of 12.0 for HBsAg carriers and 13.8 for patients with anti-HCV. Compared with those without HBsAg and anti-HCV, there was a significantly positive linear trend for developing cirrhosis with the presence of HBsAg alone (odds ratio = 19.9), anti-HCV alone (odds ratio = 49.0), and those positive for HBsAg and anti-HCV (odds ratio = 81.8) (P = 0.00001). The population-attributable risk for developing liver cirrhosis was estimated as 10.8% for anti-HCV alone, 55.2% for HBsAg alone, and 9.4% for both anti-HCV and HBsAg in southern Taiwan. In conclusion, this study shows that hepatitis B and C virus infection act independently and synergistically in the development of non-alcoholic liver cirrhosis among Chinese in Taiwan.

[Relaxation of coronary arterial smooth muscle and depolarization of cell membrane potential by selenium]

Selenium (Se) is an important trace element to the human being. The effects of selenium on contraction and cell membrane potential of coronary arterial smooth muscle were studied in guinea pig by isometric force development of strips and intracellular recording method. It was showed that Se caused vascular smooth muscle relaxation and depolarization of the cells in a dose dependent manner. Inhibitory effect of Se on KCl- or ACh-induced contraction could be quantitatively assessed by a rightward shift of the concentration-response curve. Furthermore, Se increased KCl-induced depolarization and decreased ACh-induced hyperpolarization.

[Studies on chemical constituents from solvent extracts of Poria cocos (Schw.) Wolf]

Crystals I-N were isolated from the ethereal extracts of Poria cocos and identified respectively as O-acetyl-pachymic acid (I), 3 beta-hydroxy-lanosta-7,9(11),24-trien-21-oic acid (II), beta-amyrin acetate (III) and 3 beta-hydroxy-16 alpha-acetoxy-lanosta-7,9(11),24-trien-21-oic acid (N). Crystal III was obtained from P. cocos for the first time, and crystal N was newly discovered.

Anorectal anomaly: neuropathological changes in the sacral spinal cord

The study was carried out on the bodies of five full-term newborn babies and 10 newborn patients with anorectal anomalies (four of whom had the high deformity, one had the intermediate, and five had the low). Serial transverse sections of the sacral spinal cords at 30 microns were made and stained with Nissle's. It was found that in the medial column of the sacral spinal cord there were two groups of motoneurons: posteriomedian group (group A) and anteriomedian group (group B). The former was found mainly in S3 and S4 and the latter extended from caudal S4 to caudal S2. In six of the 10 deformitive cases the cross-sections of the S5 showed a large diamond-shaped central canal and a thin conus medulla which could be distinguished as the basal and alar laminae; in one case, the lower part of the central canal and the anterior median fissure appeared undeveloped; in one case, the lower part of the central canal was divided into two large canals by a sagittal septum; and in the other two cases, their central canals appeared widened and flattened. Additionally, the average numbers of motoneurons in the group B of the high or intermediate deformity and the low deformity were 13.4% and 61.1%, respectively, of the normal number, and the corresponding numbers of group A were 61.3% and 77.7%, respectively, of the normal number. The observations suggest that sacral myelodysplasia is one of the neuropathological features in anorectal anomaly and may be responsible for the pathological changes in its peripheral nerve system.

Serum SP1, HPL levels and urinary estrogen/creatinine ratio in the detection of low birth weight

Serum pregnancy specific beta 1 glycoprotein (SP1), human placental lactogen (HPL) and urinary estrogen/creatinine (E/C) ratio levels were determined to study their clinical significance in predicting low birth weight (LBW) in women with normal pregnancy and patients with LBW. The results showed that the sensitivity of urinary E/C ratio was better than that of serum SP1 and HPL, and was increased gradually with the reduction of fetal weight. The specificity in predicting LBW decreased gradually with the increase of serum SP1 and HPL levels and urinary E/C ratio. When serum SP1 level was less than 50 mg/L, HPL less than 2.0 mg/L, and E/C ratio less than 10, their specificity could increase over 90%. It is suggested that multi-indexes measurement would improve the accuracy for predicting LBW. We conclude that SP1, HPL and E/C ratio measurement could be an useful index for predicting LBW.

The role of hepatitis C virus in chronic hepatitis B virus infection

To investigate the influence of hepatitis C virus (HCV) infection on patients with chronic hepatitis B virus (HBV), the presence of antibody against C100-3 antigen of HCV (anti-HCV) was examined in 420 patients with chronic HBV infection and 275 healthy subjects. It was found that the prevalence of HCV infection increased in parallel with the severity of liver damage. The positive rates of anti-HCV were as follows: healthy subjects, 2.9% (8/275); asymptomatic carriers, 2.6% (5/193); chronic hepatitis, 5.2% (3/58); liver cirrhosis, 11.4% (8/70); hepatocellular carcinoma (HCC), 12.1% (12/99). To elucidate the interaction of these two viruses in hepatocellular carcinoma, 128 HCC patients and 384 age-matched and sex-matched subjects were further analyzed. Eighty-seven of 128 HCC patients (68.0%) were only positive for HBsAg, 13 patients (10.1%) were only anti-HCV positive, and 12 (9.4%) were positive for both markers. The presence of HBsAg and anti-HCV was associated strongly with HCC. Moreover, the risk of HCC was significantly higher when both HBsAg and anti-HCV were present simultaneously. These results suggested that concurrent HCV infection might accelerate the progression of chronic HBV infection and may contribute to the pathogenesis of HCC in patients with chronic HBV infection.

Phosphorylation and modulation of a kainate receptor (GluR6) by cAMP-dependent protein kinase

Ligand-gated ion channels gated by glutamate constitute the major excitatory neurotransmitter system in the mammalian brain. The functional modulation of GluR6, a kainate-activated glutamate receptor, by adenosine 3',5'-monophosphate-dependent protein kinase A (PKA) was examined with receptors expressed in human embryonic kidney cells. Kainate-evoked currents underwent a rapid desensitization that was blocked by lectins. Kainate currents were potentiated by intracellular perfusion of PKA, and this potentiation was blocked by co-application of an inhibitory peptide. Site-directed mutagenesis was used to identify the site or sites of phosphorylation on GluR6. Although mutagenesis of two serine residues, Ser684 and Ser666, was required for complete abolition of the PKA-induced potentiation, Ser684 may be the preferred site of phosphorylation in native GluR6 receptor complexes. These results indicate that glutamate receptor function can be directly modulated by protein phosphorylation and suggest that a dynamic regulation of excitatory receptors could be associated with some forms of learning and memory in the mammalian brain.

Secular trend and geographical variation in hepatitis A infection and hepatitis B carrier rate among adolescents in Taiwan: an island-wide survey

During the last two decades an economic boom has occurred in Taiwan, a region where the prevalence of both hepatitis A and B virus infection was formerly very high. To examine the impact of socioeconomic developments on the secular trend and geographical variation in hepatitis A and B virus infection, 875 adolescents selected randomly from 20 junior high schools were studied. Serum samples collected from the subjects were tested for hepatitis A antibody (anti-HAV) and hepatitis B surface antigen (HBsAg) by enzyme immunoassay using commercial reagents. The anti-HAV prevalence increased from northern through central to southern Taiwan; the prevalence was highest in aboriginal townships and lowest in metropolitan precincts. This striking variation in anti-HAV prevalence in different geographical locations and at different urbanization levels remained significant in multiple logistic regression analysis. The HBsAg prevalence was significantly higher in aboriginal townships than in rural and urban townships and metropolitan precincts. In addition, HBsAg prevalence was related inversely to the number of physicians per 1,000 population. The prevalence of both anti-HAV and HBsAg declined significantly during the last decade in Taipei City and County. The decrease in anti-HAV prevalence may be due to improvements in environmental hygiene, water supply, and food sanitation, while the decline in the HBsAg carrier rate may result from the use of disposable needles and syringes as well as screening for HBsAg in blood banks.

Alpha-fetoprotein in patients with hepatocellular carcinoma after transcatheter arterial embolization

To assess the usefulness of alpha-fetoprotein (AFP) in monitoring treatment effects of transcatheter arterial embolization (TAE) in hepatocellular carcinoma (HCC) patients, a total of 31 sets of AFP levels after TAE in 21 HCC patients were analysed by linear regression between logarithmic AFP levels and days. Eleven sets of AFP data with poor linear declination were accompanied with poor TAE results except in one patient who had chronic hepatitis with acute exacerbations. Twenty sets of data with good linear declination in the first month after TAE indicated good TAE results. Seven of them showed no evidence of tumour recurrence nor elevated AFP levels within a follow-up of 6 months. The mean, standard deviation and range of half-lives of AFP in the non-recurrent group were 5.0, 1.6 and 2.9-7.2 days, respectively. The others experienced late tumour recurrence that was detected by rebound of AFP levels except one who had another non-AFP-secreting HCC. Thus, the results might be used as a reference in monitoring the treatment effects of TAE and the timing selection of repeated TAE.

Effects of exogenous gamma-aminobutyric acid on experimental arrhythmias

The effects of exogenous gamma-aminobutyric acid (GABA) 10 mg.kg-1 iv in preventing arrhythmias induced by drugs and ischemia were studied in mice, rats, and guinea pigs. It was found that the threshold dose of aconitine inducing arrhythmia in mice and the recovery rate to normal sinus rhythm increased significantly, ED50 of GABA was 5.4-5.8 mg.kg-1. The duration of ventricular tachycardia (VT) induced by aconitine in rats was shortened (P < 0.01). The incidence and the mortality of ventricular fibrillation (VF) in GABA group were decreased to 0/10 vs 6/10 and 5/10 in control, respectively (P < 0.05). The doses of ouabain to induce ectopic beats (EB), VT, VF, and cardiac arrest (CA) in guinea pigs were increased (P < 0.01). The incidence of VF induced by coronary artery ligation in rats was decreased to 0/5 in GABA group vs 4/5 in control group (P < 0.01). The total amount of EB, total time of VT, and VF were 66%, 41%, and 0% of the control group, respectively. The anti-arrhythmic effects of GABA were dose-dependent and as potent as procainamide (10 or 5 mg.kg-1, iv). The results suggest GABA (10 mg.kg-1, iv) may be useful for the prevention of VT and VF.

Relationship between fatty liver, alanine aminotransferase, HBsAg and hepatitis C virus

A community health survey of 923 residents aged 30 years or more was performed in Putai Township of Taiwan. To elucidate the relationships between hepatitis C virus (HCV) and surrogate tests for non-A, non-B hepatitis in hyperendemic areas of hepatitis B virus (HBV) serum levels of alanine aminotransferase (ALT), triglycerides, cholesterol, hepatitis B surface antigen (HBsAg) and antibody to HCV (anti-HCV) were examined. Glucose tolerance tests and the history of diabetes treatment were used to define the diabetes status. Fatty liver was diagnosed by sonography. The prevalence of anti-HCV was 2.6% (95% confidence interval, 1.6-3.6%). Elevated ALT and fatty liver were significantly associated with anti-HCV in univariate analysis. Anti-HCV was not an associated factor for fatty liver after adjusting for serum triglycerides and cholesterol, sex, body mass index and diabetes status through multiple logistic regression. However elevated ALT was still associated with anti-HCV after adjusting for serum triglycerides, sex, body mass index, HBsAg and age through multiple linear regression. The anti-HCV prevalence was similar between HBsAg-positive and negative subjects. Aggregation of HCV infection was found among spouses. It was concluded that elevated ALT and intimate contact with HCV carriers might be associated factors for HCV infection, and that HBV infection and fatty liver were not related to HCV infection in Taiwan.

The transport barrier of epithelia: a comparative study on membrane permeability and charge selectivity in the rabbit

The transport barrier of the epithelial presents one of the major problems limiting the effective use of these tissues as alternate delivery routes for macromolecules such as peptides and proteins. In the present study, two membrane transport properties, namely, the permeability and permselectivity of the shunt pathway, were investigated and compared in various tissues including the nasal, tracheal, bronchial, buccal, rectal, vaginal, corneal, epidermal, duodenal, jejunal, ileal, and colonic epithelia. Membrane permeability was evaluated using a combined method based on electrical conductance and flux measurements of a hydrophilic fluorescent probe, 6-carboxy fluorescein (CF). Membrane permselectivity or the charge discriminating ability of the membrane was evaluated by KCl diffusion potential measurements. The results indicate that all epithelia under investigation possess a relatively high degree of permeation barrier and are highly selective for the absorption of positively charged solutes. Shunt path permeability was found to vary greatly among tissues from different epithelia, whereas membrane charge selectivity was relatively constant in these tissues. A good correlation was observed between membrane electrical conductance and steady-state flux of CF, indicating a paracellular transport of the compound. The rank order of the intrinsic membrane permeability was as follows: intestinal approximately nasal greater than or equal to bronchial greater than or equal to tracheal greater than vaginal greater than or equal to rectal greater than corneal greater than buccal greater than skin. Membrane permselectivity, expressed as the ratio of transport number (positive over negative), ranges from 1.78 for the buccal to 1.33 for the rectal epithelium.(ABSTRACT TRUNCATED AT 250 WORDS)

State dependent spike detection: validation

We present a formal validation of the method of state dependent spike detection; its principle and initial results were given in Gotman and Wang (1991). The method utilizes different procedures for elimination of non-epileptic transients according to state (active or quiet wakefulness, sleep stages); it also varies detection sensitivity according to state. Twenty new 100 min recordings were obtained from 20 unselected patients, covering active wakefulness, quiet wakefulness and various sleep stages. Results indicated that, while the total number of detections was reduced by 15%, true detections increased by 39% and false detections decreased by 60%. This significant improvement is due to the fact that wave morphology is now considered within its spatial context and particularly within a wide temporal context.

Sensory nerve endings in the puborectalis and anal region of the fetus and newborn

The study was carried out in seven fetuses (ovulation ages were 16, 18, 20, 22, 26, 28, and 31 weeks, respectively) and in five full-term newborn babies. The modified Bielschowsky method and Barker's block silver impregnation were used. It was found that the muscle spindle was arranged in the puborectalis and the external sphincter muscles from the 20th week onward; the tendon organ was located in association with the musculo-tendinous junction of the puborectalis from the 20th week onward; the Pacinian corpuscle lay in the plane of cleavage between the internal anal sphincter and the external anal sphincter from the 22nd week onward, and in the presacral space from the 28th week onward, and the later lagged behind the former in development; the globular endings lay in the presacral space from the 28th week onward; and the free nerve ending was distributed in the epithelium of the anal mucosa and the epidermis around the anus from the 31st week onward. These sensory nerve endings tend to mature gradually with increasing age. It was concluded that these endings may be responsible for the reflex of the external anal sphincter and the anal sensation.

Clinical utility of pulsed Doppler in the detection of arterioportal shunting in patients with hepatocellular carcinoma

Ninety-seven patients with hepatocellular carcinoma had duplex scanning from the patent or residual portal lumen and comparative angiography. Duplex ultrasonography identified five of nine patients with angiographic evidence of arterioportal shunting. Furthermore, Doppler results indicated the presence of the shunt in one patient without angiographic evidence. Duplex scanning from the portal lumen may be useful in the detection of arterioportal shunting. This procedure can be used to evaluate the hemodynamic change of the recipient portal vein under natural physiologic conditions. However, small shunts without hepatofugal portal blood cannot be detected by this procedure.

The role of hepatitis B and C viruses in hepatocellular carcinoma in a hepatitis B endemic area. A case-control study

To investigate the role of hepatitis B (HBV) and C viruses (HCV) in hepatocellular carcinoma (HCC) in an HBV endemic area and elucidate the interaction of these two viruses, a case-control study of 128 patients with HCC and 384 age-matched and sex-matched control subjects was done. The positive rates of hepatitis B surface antigen (HBsAg, 77.3%, 99 of 128) and anti-HCV (19.5%, 25 of 128) in patients with HCC were significantly higher than in control subjects (P less than 0.001). Both HBsAg and anti-HCV were important risk factors for HCC (relative risks, 13.96 and 27.12, respectively), and the risk for HCC was elevated significantly to 40.05 (95% confidence interval, 12.57 to 127.6) when HBsAg and anti-HCV were considered simultaneously. These results suggested that HBV and HCV were associated highly with HCC in an HBV endemic area and that these two viruses might contribute independent but synergistic effects to the pathogenesis of HCC.

The role of hepatitis B and C viruses in hepatocellular carcinoma in a hepatitis B endemic area. A case-control study

To investigate the role of hepatitis B (HBV) and C viruses (HCV) in hepatocellular carcinoma (HCC) in an HBV endemic area and elucidate the interaction of these two viruses, a case-control study of 128 patients with HCC and 384 age-matched and sex-matched control subjects was done. The positive rates of hepatitis B surface antigen (HBsAg, 77.3%, 99 of 128) and anti-HCV (19.5%, 25 of 128) in patients with HCC were significantly higher than in control subjects (P less than 0.001). Both HBsAg and anti-HCV were important risk factors for HCC (relative risks, 13.96 and 27.12, respectively), and the risk for HCC was elevated significantly to 40.05 (95% confidence interval, 12.57 to 127.6) when HBsAg and anti-HCV were considered simultaneously. These results suggested that HBV and HCV were associated highly with HCC in an HBV endemic area and that these two viruses might contribute independent but synergistic effects to the pathogenesis of HCC.

Duplex pulsed Doppler sonography in the differential diagnosis of hepatocellular carcinoma and other common hepatic tumours

180 previously untreated consecutive patients with liver tumours (308 lesions), including 104 hepatocellular carcinomas (148 lesions), 43 metastases (116 lesions) and 33 haemangiomas (44 lesions), were studied to determine the value of duplex sonography in the differentiation of hepatocellular carcinoma from other tumours. For lesions measuring less than or equal to 5 cm in diameter, hepatocellular carcinoma demonstrated the highest rate and haemangioma demonstrated the lowest rate of Doppler signals from within the lesions. To differentiate malignancy from haemangioma, the presence or absence of Doppler signals from these lesions were used as criteria. The specificity and positive predictive value were very high (100%, 100%), but the sensitivity, negative predictive value and accuracy were low (61.5%, 48.3%, 71.7%, respectively). With one exception, all lesions measuring less than 3 cm in diameter with detectable Doppler signals were hepatocellular carcinoma. Using these results it is possible to differentiate hepatocellular carcinoma from metastases and haemangioma with high sensitivity, specificity, positive and negative predictive value, and accuracy (80.8%, 96.4%, 95.5%, 84.4%, 88.9%, respectively, for metastases; 80.8%, 100%. 100%, 81.5%, 89.6%, respectively, for haemangioma). We conclude that Doppler signals from within a lesion in combination with its size can aid differentiation of hepatocellular carcinoma from two other kinds of common hepatic tumour.

Enzyme inhibitory assay using monoclonal antibody against acid alpha-D-glucosidase in prenatal diagnosis to identify homozygotes of Pompe's disease

From January 1985 to January 1990, measurements of acid alpha-D-glucosidase activity in amniocytes or chorionic villus samplings were done for 24 pregnant mothers who were carriers of Pompe's disease. 6 women had two subsequent pregnancies. Amniotic fluid was obtained by transabdominal amniocentesis performed on 10 of them, while chorionic villus samplings were obtained in the other 20. The results showed that 7 (23.3%) cases were homozygotes, 16 (53.4%) cases were heterozygotes, and 7 (23.3%) cases were normal. Pregnancies were terminated in the homozygotic group. Final diagnosis was confirmed by either skin fibroblast culture or clinical course. However, we found that there was overlap in the acid alpha-D-glucosidase activity of amniocytes between homozygotes and heterozygotes due to residual activity of neutral alpha-D-glucosidase. In an attempt to identify heterozygotes for Pompe's disease, we established an enzyme inhibitory assay using monoclonal antibody (mAb) against acid alpha-D-glucosidase. Comparing the differences in alpha-D-glucosidase activity before and after mAb treatment the homozygotes were significantly lower than heterozygotes (P less than 0.001). There was no more overlap in the difference of acid alpha-D-glucosidase activity before and after mAb treatment between heterozygotes and homozygotes in amniocytes. This modified enzyme inhibitory assay should facilitate homozygote detection. Comparing acid alpha-D-glucosidase activity between CVS and amniocytes, the enzyme activity in CVS is about 5 times higher than in amniocytes. There was no overlap in the acid alpha-D-glucosidase activity between homozygotes and heterozygotes. Therefore, CVS is better than amniocentesis in the prenatal diagnosis of Pompe's disease.

Anti-HCV antibody in Chinese cirrhotic patients with or without hepatocellular carcinoma: relation to multitransfusion

To investigate the positive rates of antibodies to hepatitis C virus (anti-HCV) in Chinese cirrhotic patients with or without hepatocellular carcinoma and to evaluate the influence of blood transfusion on the prevalence of anti-HCV in such patients, a longitudinal study in 30 cirrhotic patients (17 combined with hepatocellular carcinoma) was carried out. Five patients (16.7%) were anti-HCV positive before transfusion. The positive rate of anti-HCV in HBsAg-positive patients and HBsAg-negative patients was 9.5% (2/21) and 33.3% (3/9), respectively. The positive rates in cirrhotic patients with or without hepatocellular carcinoma were 23.5% (4/17) and 7.7% (1/13), respectively. The positive rate of anti-HCV increased significantly after multitransfusion, and the estimated infectivity of blood products was 6.1 patients per 1000 units of blood products. It was concluded that the aetiological role of hepatitis C virus on liver cirrhosis and hepatocellular carcinoma in the endemic area of hepatitis B virus is not so important as in Western countries, and transfusion might result in an overestimated pathogenic effect of hepatitis C virus in cirrhotic patients and patients with hepatocellular carcinoma.

Radiotherapy in the treatment of hepatocellular carcinoma and its metastases

A study was conducted to evaluate the effect of external radiation therapy on hepatocellular carcinoma (HCC) and its metastatic lesions. A total of 33 patients with cytopathologically proven HCC were subjected to radiation therapy over a 4-year period, and treatment was discontinued in 8 cases due to jaundice, severe discomfort, or early mortality. Thus, 25 patients with 28 lesions underwent irradiation with a total dose ranging between 3000 and 5600. Of these, seven were irradiated for liver tumors, and the results showed that two lesions decreased in size, the symptoms improved in 1 case, and another patient maintained stable disease for 4 months. Among the 21 metastatic lesions treated, only 2 patients failed respond to the treatment. Nine subjects were irradiated for bone metastases, and the bone pain subsided in all but one case. The survival for bone metastasis was as long as 23 months when the primary tumor was treated effectively. Three of the four cases of irradiated skin nodules disappeared and had not recurred after 5 months, 1 year, and 4 years, respectively. Tumor shrinkage or symptoms of relief were noted for three abdominal lymph nodes, one neck lymph node, one pleural tumor, and one lung tumor. Clinical improvement associated with a stable lesion was observed in two patients with brain metastasis. Follow-up revealed regrowth of the tumor or recurrence of symptoms in most of the patients. However, none of the patients died as a direct result of a metastatic lesion. Although external radiation therapy is palliative in intent, it appears to be useful in the treatment of HCC and its metastatic lesions.

Treatment of hepatocellular carcinoma by transcatheter arterial chemoembolization and analysis of prognostic factors

A total of 100 patients with histologically proven hepatocellular carcinoma (HCC) underwent transcatheter arterial chemoembolization (TACE) and were followed for more than 1 year and 10 months. Portal vein branch thrombosis was diagnosed in 14 patients, and extrahepatic metastasis was noted in 11 subjects. The embolization material used was iodized oil (0.1-0.2 ml/cm tumor area at its maximal diameter), which was prepared by pumping with contrast agent and then mixed with anticancer drugs; Gelfoam particles measuring 1-2 mm in size were subsequently injected. The overall cumulative 0.5- 1-, 2-, and 3-year survival rates were 81%, 57%, 31%, and 21%, respectively. Patients with an intact capsule and those with solitary lesions, especially when the tumor diameter was < 5 cm, achieved a higher survival rate. In contrast, incomplete TACE, extrahepatic metastasis, and portal vein thrombosis were associated with the worst outcome. Patients with positive HBsAG and diffuse or multiple tumors also showed a poor outcome. Early diagnosis and early treatment of HCC are the keys for the achievement of better clinical results.

The cellular electropharmacology of mexiletine in papillary muscles of guinea pigs chronically treated with amiodarone

OBJECTIVE

The combination of mexiletine and amiodarone has proved useful in the control of serious ventricular arrhythmias, but the electrophysiological basis for their effectiveness in combination is unknown. The objective of this study was to compare the effects of mexiletine on action potential parameters of papillary muscles taken from guinea pigs chronically treated with amiodarone, with tissue taken from a control group.

DESIGN

The effects of 12.5 to 200 microM mexiletine on action potential parameters of papillary muscles taken from guinea pigs chronically treated with amiodarone were compared with tissue taken from a control group, at frequencies of 1.0, 1.5 and 3.0 Hz, using standard microelectrode techniques. Onset of use-dependent block was assessed by 30 beat trains, and recovery from block by extrastimuli at diastolic intervals ranging from 200 to 5000 ms at both 1.5 and 3.0 Hz.

ANIMALS

Eighteen four-week-old guinea pigs were randomly divided into two groups. One group received amiodarone in a loading dose of 20 mg/kg/day by intraperitoneal injection for one week, followed by 10 mg/kg/day for 15 weeks. The control animals were given equivalent volumes of dextrose intraperitoneally for 16 weeks.

MAIN RESULTS

Mexiletine depressed the maximum rate of depolarization of phase 0 of the action potential (Vmax) in a concentration- and use-dependent fashion. Whereas chronic amiodarone treatment did not alter steady-state Vmax values, the extent of tonic Vmax depression induced by mexiletine was decreased, while use-dependent depression was increased. Mexiletine combined with amiodarone increased effective refractory period prolongation from 306.7 +/- 27.2 to 348.8 +/- 37.2 ms, while action potential duration shortening of mexiletine was moderated from 134.0 +/- 19.8 to 151.0 +/- 8.3 ms (to 90% repolarization at 3 Hz in the presence of 200 microM mexiletine).

Systemic amyloidosis presenting as splenic tumor

We report a case of amyloidosis manifesting as a splenic tumor and pleural effusion. Only one case of a splenic amyloid tumor has been reported in the literature, but its radiological findings were not described. Therefore, we present the computed tomographic (CT), sonographic, and angiographic features of splenic amyloid tumor.

Duplex pulsed Doppler sonography of hepatocellular carcinoma treated with transcatheter arterial embolization

Thirty-one patients with hepatocellular carcinoma underwent duplex scanning of their lesions with comparative angiography and serum alpha-fetoprotein determinations before and after transcatheter arterial embolization. Duplex ultrasound correctly identified 26 patients with patent tumor vessels after embolization. The Doppler signals became undetectable after embolization in the other five patients. Comparative angiography demonstrated good devascularization of their lesions. However, tiny tumor blush or small satellite nodules around the periphery of the devascularized masses were found. Therefore, the presence of signals after therapy indubitably needs further embolization. The timing of the second embolization for the patient with undetectable Doppler signals after the first embolization needs to be justified by further evaluations.

Comprehensive assessment of long-term postoperative continence in pediatric imperforate anus. Clinical, manometric and contrast studies

109 patients with imperforate anus were followed up postoperatively for 5 to 28 years. Postoperative continence was evaluated by anorectal manometry, barium enema and clinical symptoms. A comprehensive assessment system, combining the clinical and objective systems was designed which can reflect postoperative anal continence function completely and objectively. It is useful for determining the causes of incontinence and its treatment.

The single cysteine residue on an alpha family chick liver glutathione S-transferase CL 3-3 is not functionally important

Chick liver glutathione S-transferase CL 3-3, expressed using a baculovirus system in Spodoptera frugiperda (SF9) cells, contains a single cysteine residue per subunit. This enzyme was modified with iodoacetamide. Amino acid analysis indicates that 0.85 +/- 0.10 cysteine residue was modified per enzyme subunit. GST CL 3-3 modified with iodo[14C]acetamide was further digested with trypsin and the isotope-labelled fragments were isolated. The fragment containing the cysteine residue accounts for 53% of the total labels. The S-carbaminomethylated protein retains the glutathione conjugating activity. Therefore, the cysteine residue is not essential for the enzymatic activity of CL 3-3.

Regulation of kainate receptors by cAMP-dependent protein kinase and phosphatases

In the mammalian central nervous system, receptors for excitatory amino acid neurotransmitters such as the alpha-amino-3-hydroxy-5-methyl-4- isoxazolepropionic acid (AMPA)-kainate receptor mediate a large fraction of excitatory transmission. Currents induced by activation of the AMPA-kainate receptor were potentiated by agents that specifically stimulate adenosine 3',5'-monophosphate (cAMP)-dependent protein kinase A (PKA) activity or were supported by intracellular application of the catalytic subunit of PKA by itself or in combination with cAMP. Furthermore, depression of these currents by a competitive inhibitor of PKA indicates that AMPA-kainate receptors are regulated by endogenous PKA. Endogenous protein phosphatases also regulate these receptors because an inhibitor of cellular phosphates enhanced kainate currents. Modulation of PKA and phosphatases may regulate the function of these receptors and thus contribute to synaptic plasticity in hippocampal neurons.

State-dependent spike detection: concepts and preliminary results

In traditional methods of spike detection, spikes are defined in absolute terms (duration, amplitude) or relative to a few seconds of background. These methods result in many false positive detections during long-term epilepsy monitoring because of numerous artefacts and non-epileptic transients. To reduce significantly false detection, we propose to render spike detection sensitive to the state of the EEG. We thus defined 5 states (active wakefulness, quiet wakefulness, desynchronized EEG, phasic EEG and slow EEG) and designed a method for automatic state classification. We then designed procedures for identification of non-epileptic transients (eye blinks, EMG, alpha, spindles, vertex sharp waves). These procedures are to be applied only in the state in which they are likely to occur (e.g., eye blinks in wakefulness). We present preliminary results from 14 recordings each lasting 100 min, which indicate a state classification reliability of 85-90%, reduction in false detection of 65-90% if state classification were perfect; true spikes lost as a result of these procedures were under 5%. These results are encouraging and validate the concept of a spike detection system which analyses a wide temporal and spatial context before deciding the significance of a wave form.

Transverse modes of an apertured laser

Modes of a diaphragmed laser are expressed as linear combinations of Laguerre-Gauss functions and computed from the resonance condition. Hard and soft apertures are considered. Explicit results are given in both cases for the phase and amplitude distributions inside and outside a plano-concave cavity and for the three modes having the lowest losses. Deformations of modes with the diameter of the diaphragm are also given, showing the evolution of lateral lobes.

Duplex pulsed Doppler sonography of portal vein thrombosis in hepatocellular carcinoma

Sixteen patients with hepatocellular carcinoma had duplex pulsed Doppler scanning of the portal thrombus and comparative angiography. Fifteen patients demonstrated detectable Doppler signals from the thrombus. The Doppler signals were corroborated by the "thread-and-streaks" sign on angiography in eight patients. This suggests that signals come from tumor vessels within the thrombus. Therefore, the presence of Doppler signals in the thrombotic portal venous system is not only due to partial obstruction of the lumen. Tumor thrombus from hepatocellular carcinoma must be considered, especially when the detectable signals are pulsatile waves.

[Estrogen and progesterone receptors in esophageal carcinoma cells]

Distribution of estrogen and progesterone receptors (ER and PR) was studied in esophageal tissue (48 patients with esophageal carcinoma, 20 normal subjects and 12 fetuses) and Eca 109 cell line using enzyme-linking affinity immunohistochemistry method. In the meantime, plasma estradiol and progesterone levels were determined in 8 patients with esophageal carcinoma using radioimmunoassay method. The results showed that the positive rates of ER and PR in esophageal carcinoma were 43.75% (21/48) and 39.58% (19/48). Both ER and PR were positive in Eca 109 cell line whereas they were negative in the control groups. Sex and grade of cancer were the factors influencing the positive rates of ER and PR. It is indicated that carcinogenesis of esophageal carcinoma might be related to sex hormone metabolism. The measurement of ER and PR may be useful in clinical practice.

Abdominal sonographic screening in a single community

A health survey, on adults aged 30 years or more, was carried out at 3 villages on the southwest coast of Taiwan. A total of 923 cases (42.6%) of the 2,166 population participated in the survey. The estimated total population prevalence rates were as follows: no gross lesion (60.5%), fatty liver (25.2%), biliary stone (5.2%), gall bladder polyp (1.9%), hepatic hemangioma (1.4%), liver cyst (0.9%) and renal cyst (2.9%). The prevalence rates of gall bladder polyp and renal cyst were higher in men, while that of fatty liver was higher in women. There was an increase in the prevalence with age for fatty liver in females. The results might be a reference about the above findings among Chinese in Taiwan.

The cellular electropharmacology of mexiletine combined with sotalol in porcine papillary muscle and Purkinje fibre. I. Alteration of mexiletine-induced Vmax depression

Using standard microelectrode techniques, the authors compared the effects of 15 to 125 microM concentrations of mexiletine, 31 to 500 microM concentrations of sotalol and 15 to 125 microM of mexiletine combined with 125 microM sotalol, on the beat-to-beat maximum rate of depolarization of phase 0 of the action potential (Vmax) of porcine papillary muscles and Purkinje fibres stimulated by 30 beat trains at a frequency of 1 Hz. Sotalol alone had no effect on Vmax. Mexiletine caused both tonic and use-dependent depression of Vmax in papillary muscle. In the presence of sotalol, tonic Vmax depression was exaggerated, while use-dependent depression was attenuated. In Purkinje fibres, mexiletine exposure resulted in tonic Vmax depression, but no use-dependence could be demonstrated at this frequency. These results are best explained in the context of the modulated receptor hypothesis with the added consideration of two receptors--one within and one external to the sodium channel.

The cellular electropharmacology of mexiletine combined with sotalol in porcine papillary muscle and Purkinje fibre. II. Effects on action potential duration and refractoriness

Using standard microelectrode techniques, the authors compared the effects of 15 to 125 microM concentrations of mexiletine, 31 to 500 microM concentrations of sotalol and 15 to 125 microM of mexiletine combined with 125 microM sotalol, on the beat-to-beat action potential duration and refractoriness of porcine papillary muscles and Purkinje fibres stimulated by 30 beat trains at a frequency of 1 Hz. Sotalol alone prolonged action potential duration and effective refractory period without altering their ratio. Mexiletine shortened action potential duration while prolonging refractoriness. When the two drugs were combined, action potential duration was shortened to the same extent as with mexiletine alone, but refractoriness, particularly in papillary muscle, was further prolonged. These changes suggest additive inhibition of the sodium window current by both drugs. Purkinje action potential duration was longest in the first beat of the train, while in papillary muscle, this beat was shortest. Exposure to either or both drugs eliminated the prolongation of duration of the first beat of the train in Purkinje fibre. Thus, the phenomenon of restitution, which prolongs the duration of the first beat after a long diastolic interval, appears also to be related to the sodium window current.

Cardiovascular effect and stimulus-dependent inhibition of superoxide generation from human neutrophils by tibenelast, 5,6-diethoxybenzo(b)thiophene-2-carboxylic acid, sodium salt (LY186655)

Tibenelast (LY186655), 5,6,-diethoxybenzo(b)thiophene-2-carboxylic acid, sodium salt, is an orally active anti-anaphylactic compound in guinea pigs, and has been shown to prevent bronchospasm in moderately severe asthmatic patients. Pharmacological studies with tibenelast demonstrated that it is a selective phosphodiesterase (PDE) inhibitor in that it is moderately active against the lung and stomach enzyme while being a very weak inhibitor of the heart enzyme. The compound was without cardiovascular effects at anti-anaphylactic doses. In contrast to theophylline, tibenelast did not have a direct inotropic effect in the cat papillary muscle system. The concentration that inhibited 50% of the enzymatic activity (IC50) for tibenelast was 20- to 30-fold lower for neutrophil PDE than for PDE of other tissues. It was 100 times more potent than aminophylline in inhibiting superoxide generation from platelet-activating factor (PAF)-primed polymorphonuclear leukocytes (PMNL) challenged with chemotactic factor, N-formyl-methionyl-leucyl-phenylalanine. However, tibenelast was less effective in the tumor necrosis factor-primed system, and did not inhibit superoxide generation during phagocytosis or when other soluble stimuli, such as phorbo-12-myristate-13-acetate or the calcium ionophore A23187, were used. Furthermore, tibenelast did not inhibit enzymes involved in arachidonic acid metabolism. These results suggest that tibenelast probably inhibits superoxide release from PMNL via a selective inhibition on PDE.