Regulation of the tyrosine hydroxylase and dopamine beta-hydroxylase genes by the transcription factor AP-2

The retinoic acid-inducible and developmentally regulated transcription factor AP-2 plays an important role during development. In adult mammals, AP-2 is expressed in both neural and non-neural tissues. However, the function of AP-2 in different neuronal phenotypes is poorly understood. In this study, transcriptional regulation of tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH) genes by AP-2 was investigated. AP-2 binding sites were identified in the upstream regions of both genes. Electrophoretic mobility shift assays (EMSA) and DNase I footprinting analyses indicate that the AP-2 interaction with these motifs is more prominent in catecholaminergic SK-N-BE(2)C and CATH.a than in non-catecholaminergic HeLa and HepG2 cell lines. Exogenous expression of AP-2 robustly transactivated TH and DBH promoter activities in non-catecholaminergic cell lines. While AP-2 regulates the DBH promoter activity via a single site, transactivation of the TH promoter by AP-2 appears to require multiple sites. In support of this, mutation of multiple AP-2 binding sites but not that of single site diminished the basal promoter activity of the TH gene in cell lines that express TH and abolished transactivation by exogenous AP-2 expression in cell lines that do not express TH. In contrast, mutation of a single AP-2 binding site of the DBH gene completely abolished transactivation by AP-2. Double-label immunohistochemistry showed that AP-2 is coexpressed with TH in noradrenergic and adrenergic neurons in both the central and peripheral nervous systems of adult rodents. Numerous non-catecholaminergic cell groups within the spinal cord, medulla, cerebellum, and pons also express AP-2. The concentration of AP-2 in dorsomedial locations along the neuraxis suggests a regionally specific role for this transcription factor in the regulation of neuronal function. Based on these findings we propose that AP-2 may coregulate TH and DBH gene expression and thus participate in expression/maintenance of neurotransmitter phenotypes in (nor)adrenergic neurons and neuroendocrine cells.

The detection of p53 gene mutation using a microdissection technique in primary intracranial germ cell tumors

Using a microdissection technique, the contribution of the p53 mutation to tumorigenesis and prognosis in each histological subtype of the intracranial germ cell tumors (GCTs) was evaluated. Nineteen patients had primary intracranial GCTs, including 4 germinomas (GEs), 4 teratomas (TEs), 1 mixed tumor of GE and TE, and 10 mixed GCTs containing non-germinomatous malignant germ cell tumors (NG-MGCTs). After microdissection of specific subtypes, genomic DNA was screened for mutations in exons 5-8 of the p53 gene, using the dideoxyfingerprinting (ddF) followed by direct DNA sequencing. The direct sequencing revealed a total of six mutations in PCR products derived from the five cases (26%) which showed mobility shifts in ddF. Among the six mutations detected, four were missense mutations and two were silent. Missense mutations of the p53 gene tended to occur more frequently in the NG-MGCT component than in the GE or TE components (3/15 vs. 1/12 vs. 0/13). The incidence of missense mutations was not different between the survivors (3/13) and the deceased (1/6). This study suggests the possible role of the p53 gene in the tumori-genesis of NG-MGCT. However, p53 gene mutation did not correlate with the prognosis of NG-MGCT.

Recurrent asystoles associated with vasovagal reaction during venipuncture

A 17-year-old high school student presented with a history of habitual faintings. On 24-hour Holter monitoring, cardiac asystoles were recorded, the longest lasting approximately 7 or 8 seconds during venipuncture procedures. The asystole associated with venipuncture demonstrated the cardioinhibitory effects of vasovagal reaction with blood-injury phobia. He also had a positive response during head-up tilt test showing hypotension and relative bradycardia after intravenous isoproterenol injection. After administration of oral beta blocker, he did not show further or recurrent cardiac asystole during blood injury procedure on electrocardiographic examination. Venipuncture is the most common invasive medical procedure performed in hospital settings. While venipuncture is considered to be reasonably safe, serious complication may occur even when only a small volume of blood is withdrawn. Therefore, medical personnel should be prepared to provide appropriate care.

Hydrocortisone enhances allergen-specific IgE production by peripheral blood mononuclear cells from atopic patients with high serum allergen-specific IgE levels

BACKGROUND

Although there is convincing evidence that human B cells can be induced to produce IgE by a combination of interleukin 4 (IL-4) and hydrocortisone (HC) in atopic subjects, it is still uncertain if this performs the same functions in allergen-specific IgE synthesis.

OBJECTIVE

This study was designed to investigate the differences of IgE regulation between atopics and nonatopics, interactions of HC with IL-4, and the correlation between in vitro total IgE, allergen-specific IgE synthesis and serum IgE levels.

METHODS

Peripheral blood mononuclear cells (PBMCs) from 16 atopic asthma patients sensitive to Dermatophagoides farinae and seven nonatopic controls were cultured with IL-4 and/or HC. Total IgE and D. farinae-specific IgE in culture supernatant were measured by ELISA and FAST.

RESULTS

IL-4 increased total IgE synthesis in PBMCs from both atopics and nonatopics, whereas, HC had this effect only in some atopics who showed spontaneous IgE production in vitro. HC acted synergistically with IL-4 in total IgE synthesis. Their effects were more remarkable in cases with lower total serum IgE levels. PBMCs from eight of 16 atopics produced D. farinae-specific IgE in vitro either spontaneously or by IL-4 and/or HC. HC had more profound effects than IL-4 in these patients. They also showed higher total IgE synthesis by HC, and higher specific serum IgE levels than the others. IL-4 and/or HC did not induce any D. farinae-specific IgE synthesis by PBMCs from nonatopics.

CONCLUSION

HC had a more profound effect than IL-4 on the induction of D. farinae-specific IgE synthesis in atopic patients with high serum allergen specific IgE levels. Further studies to determine the causes of these effects, such as the presence of long lived allergen specific B cells as the result of the priming effect of IL-4 in vivo, may be needed.

Percutaneous endovascular stent-graft for iliac pseudoaneurysm following lumbar discectomy

In a 24-year-old woman, an iliac pseudoaneurysm following lumbar discectomy was successfully treated by percutaneous placement of a self-expanding stent-graft. A postprocedural angiogram demonstrated complete exclusion of the pseudoaneurysm without leakage of contrast agent.

Molecular evidence of natural hybridization between Fasciola hepatica and F. gigantica

Nucleotide sequences of two regions, cytochrome c-oxidase subunit 1 (CO1) and NADH dehydrogenase subunit 1 (ND1) of the mitochondrial DNA and two regions, internal-transcribed spacer 2 (ITS2) and the D2 region in the 28S rDNA (28S) of the nuclear DNA were obtained from five Korean worms of the genus Fasciola in order to elucidate their taxonomic status. The CO1 and ND1 regions are all monomorphic in the Korean worms and similar to those of F. gigantica. On the other hand, the ITS2 and D2 regions were found to be polymorphic; that is, out of five worms, two possessed a F. gigantica-type sequence, one, a F. hepatica-type sequence and two possessed sequences of both types indicating an existence of different alleles at the loci. It should be noted that these variations of the ITS2 and D2 regions co-occur at the same individual worms. This was confirmed by sequencing five to six cloned PCR products for each worm. The present study strongly suggests interspecific cross-hybridization between the two species coexisting in Korea.

Regulation of tyrosine hydroxylase gene transcription by the cAMP-signaling pathway: involvement of multiple transcription factors

The conversion of L-tyrosine to 3,4-dihydroxy-L-phenylalanine by tyrosine hydroxylase (TH) is the first and rate-limiting step in biosynthesis of catecholamine neurotransmitters. TH gene expression is regulated in a cell type-specific and cAMP-dependent manner. Evidence from this laboratory and others indicates that the cAMP response element (CRE), residing at -45 to -38 bp upstream of the transcription initiation site, is essential for both basal and cAMP-inducible transcription of the TH gene. To understand the control mechanisms of TH gene transcription in greater detail, we sought to identify and characterize the transcription factors involved in recognition and activation of the CRE of the TH gene. Remarkably, electrophoretic mobility shift assay and antibody supershift experiments indicated that all three major CRE-binding protein factors, i.e. CREB, ATF1, and CREM, may participate in forming specific DNA/protein complexes with the CRE of the TH gene. To address the transcriptional activation function of individual factors, we replaced the TH CRE with a GAL4-binding site and cotransfected this modified TH promoter-reporter gene with an effector plasmid that encodes GAL4-fused transcription factor. Our results indicate that CREB but not ATF1 can support basal promoter activity while both can robustly induce the promoter activity in response to co-expression of the catalytic subunit of cAMP-dependent protein kinase (PKA). We further show that the coactivator CBP up-regulates PKA-mediated activation of the TH promoter and, if tethered to the TH promoter by a GAL4-fusion, can robustly transactivate the TH promoter even in the absence of PKA. Collectively, our results suggest that multiple CRE-binding factors interact with the CRE and regulate, in conjunction with the coactivator CBP, the transcriptional activity of the TH gene.

Effects of crude drugs on glucose uptake in 3T3-L1 adipocytes

In this study, various water-extracted crude drugs from Radix Asparagi, Radix Ginseng, Radix Scutellariae, Cortex Lycii Radicis, Cortex Phellodendri and Radix Ophiopogonis were investigated in their effects on [3H]-2-deoxyglucose uptake in 3T3-L1 adipocytes. Following treatment of cells with various crude drugs for 60 mim, the basal [3H]-2-deoxyglucose uptake in cultured 3T3-L1 cells was changed by Radix Asparagi from 140 pmole/min/mg protein of control to 513 (0.1 mg/ml), 201 (1 mg/ml) and 97 (10 mg/ml). Glucose uptake was changed to 324 (0.1 mg/ml), 146 (1 mg/ml) and 46 (10 mg/ml) with Radix Ginseng. In the presence of Radix Scutellariae, glucose uptake was changed to 215 (0.1 mg/ml), 213 (1 mg/ml) and 34 (10 mg/ml). In the presence of Cortex Lycii Radicis, glucose uptake was 230 (0.1 mg/ml), 188 (1 mg/ml) and 38 (10 mg/ml). In the case of Cortex Phellodendri and Radix Ophiopogonis, uptake was changed to 142 (0.1 mg/ml), 132 (1 mg/ml), 24 (10 mg/ml) and 489 (0.1 mg/ml), 374 (1 mg/ml), 344 (10 mg/ml), respectively. In insulin-stimulated cells, the [3H]-2-deoxyglucose uptake was changed by Radix Asparagi from 570 pmole/min/mg protein of the control to 816 (0.1 mg/ml), 674 (1 mg/ml) and 532 (10 mg/ml). After incubation with Radix Ginseng, the glucose uptake was changed to 254 (0.1 mg/mi), 123 (1 mg/mi) to 76 (10 mg/mi). In the presence of Radix Scutellariae, the glucose uptake was changed to 315 (0.1 mg/ml), 265 (1 mg/ml) and 33 (10 mg/ml). After incubation of Cortex Lycii Radicis, the uptake activity was changed to 281 (0.1 mg/ml), 248 (1 mg/ml) and 37 (10 mg/ml). In the case of Cortex Phellodendri and Radix Ophiopogonis, the activity of glucose uptake was measured as 747 (0.1 mg/ml), 523 (1 mg/ml), 33 (10 mg/ml) and 753 (0.1 mg/ml), 740 (1 mg/ml), and 421 (10 mg/ml), respectively. These results indicate that the water-extracted materials of Radix Asparagi and Radix Ophiopogonis increase the glucose uptake in basal and insulin-stimulated 3T3-L1 adipocytes.

A case of chronic cerebral paragonimiasis westermani

We report a chronic cerebral paragonimiasis from a 41-year-old Korean man who complains a headache and weakness of left motor neuron components. Magnetic resonance images of the brain revealed conglomerates of multiple ring-like enhancements in temporo-occipital and frontal lobes of the right hemisphere. An intradermal test for paragonimiasis westermani was positive. The patient was born near an endemic area of paragonimiasis and used to eat boiled or grilled freshwater crayfish in his childhood. Nodules in the brain were resected through craniotomies. The eggs of P. westermani were identified pathologically and parasitologically in the calcified necrotic lesions. Examinations on sputum and fecal specimens for the eggs of P. westermani were shown to be negative and a chest radiograph was normal. It is presumed that the brain lesions were formed by P. westermani approximately 30 years ago.

Change of calcium and cAMP concentration by adrenoceptor agents in cultured porcine corneal endothelial cells

It has been reported that beta-adrenergic receptors are localized in the corneal endothelial cells. In this study, the change of cellular signal transduction, such as intracellular calcium and cAMP, was determined with pure adrenergic agonists and commercial antiglaucoma adrenergic agents. The intracellular calcium of cultured porcine corneal endothelial cells was inhibited by 10 microM isoproterenol and norepinephrine, but enhanced by propranolol and 50 mM KCl. In the case of phenylephrine, calcium mobility did not alter significantly. Verapamil, at 10 microM, decreased intracellular calcium concentration. In the presence of isoproterenol, cellular cAMP concentration increased from 28.8 pmole/mg protein (1 microM) to 42.2 pmole/mg protein (100 microM) compared with control of 6.07 pmole/mg protein. Incubation with commercial adrenergic eye drops, such as betaxolol, caused the cAMP concentration to increase from 21.6 pmole/mg protein (0.0005%) to 39.1 pmole/mg protein (0.05%). Adding commercial levobunolol and timolol into cells caused cellular cAMP to increase from 14.3 pmole/mg protein (0.0005%) to 840.5 pmole/mg protein (0.05%) and from 115.2 pmole/mg protein (0.00025%) to 931.0 pmole/mg protein (0.025%), respectively. However, the preservative, benzalkonium chloride, increased cellular cAMP from 15.4 pmole/mg protein (0.00001 mg/ml) to 1087.4 pmole/mg protein (0.01 mg/ml). It is concluded that the intracellular calcium of corneal endothelium decreases when the cellular adrenergic receptor is activated by agonists. Benzalkonium chloride, due to its preservative in commercial antiglaucoma agents which increases cellular cAMP, may alter corneal endothelial physiology through long-term use.

Inhibition of mouse neuromuscular transmission and contractile function by okadaic acid and cantharidin

1. Phosphorylations of cellular proteins modulate biological activities. The effects of okadaic acid (0.1 - 10 microM) and cantharidin (1 - 100 microM), inhibitors of protein phosphatases, on the synaptic transmission at the mouse neuromuscular junction were explored. 2. Both inhibitors almost completely depressed twitch forces elicited by electrical stimulation of diaphragm muscles (the IC(50)s for okadaic acid and cantharidin were 1.1+/-0.2 and 13+/-1 microM, n=5, respectively) and suppressed contractures evoked by high K(+) and ryanodine more than 70%. Contractures caused by cardiotoxin, which destroys the integrity of sarcolemma, were not depressed. 3. Both okadaic acid (10 microM) and cantharidin (100 microM) depolarized muscle membranes from approximately -80 to approximately -60 mV in a partially reversible and tetrodotoxin-sensitive manner. The initial short-term enhancement of twitch responses (up to approximately 40%) was correlated with the inhibitors-induced repetitive firings of muscle action potential. 4. Treatment with either agent resulted in nearly complete inhibitions of endplate potential (epp). The IC(50)s were 0.8+/-0.2 and 9+/-2 microM (n=5), respectively, for okadaic acid and cantharidin. On high frequency stimulation, the coefficient of epps was increased more than 10 fold and the extent of epp run-down during stimulations intensified from approximately 25 to approximately 75%. Analyses of presynaptic quantal releases revealed decreases in epp quantal content and the immediately available vesicle pool. 5. The frequency of miniature epp was initially elevated up to 2 fold then suppressed down to approximately 30%. The small reduction in the amplitude was antagonized when the membrane of endplate area was repolarized. 6. The data suggest that okadaic acid and cantharidin inhibit mobilizations of synaptic vesicles and depress Ca(2+) release from sarcoplasmic reticulum and that protein phosphatases participate in the modulation of motor function.

Transthoracic echocardiographic demonstration of massive pulmonary thrombus caused by protein C deficiency

Few cases of pulmonary embolism detected by transthoracic echocardiography (TTE) have been reported. We present a case of a patient affected by pulmonary embolism caused by protein C deficiency. Transthoracic echocardiography showed a thrombus in transit (ie, visualization of a thrombus within the pulmonary artery). A hypercoagulable state caused by deficiency of protein C is a rare cause of pulmonary thromboembolism. Our experience demonstrates a massive pulmonary thrombus resulting from such a deficiency. Transthoracic echocardiography should be considered as the first diagnostic method for patients with suspected pulmonary embolism.

Molecular cloning and immunological characterization of phosphoglycerate kinase from Clonorchis sinensis

The parasite Clonorchis sinensis was determined to utilize a large amount of external glucose to carry its energy metabolism. Phosphoglycerate kinase (PGK), a glycolytic enzyme, found in many parasites, has been identified as one of the candidate molecules distinguished from human counterparts for vaccine and drug developments. A cDNA clone purified by screening a C. sinensis cDNA library using a heterologous cDNA probe encoded a putative peptide of 415 amino acids with over 60% identities with PGKs from a number of animals. The putative peptides revealed domains corresponding to 12 beta-sheets and inner loops forming a substrate-binding cleft of animal PGKs. The gene product was overexpressed in Escherichia coli and showed a PGK-like enzyme activity. A polyclonal antibody raised against the recombinant C. sinensis PGK was specific to native C. sinensis PGK and localized it to the muscular tissue and tegument of the adult flukes. The C. sinensis PGK elicited antibodies in C. sinensis-infected rabbits. Therefore, it is proposed that C. sinensis PGK could be used as an immunoreagent in the serodiagnosis for clonorchiasis.

Reduction of neuronal damage in ischemic stroke using a combination therapy of TMB-8 with L-arginine

Treatment with a combination of a calcium antagonist TMB-8 and NO donors, L-arginine and N alpha-benzoyl-L-arginine ethyl ester (BAEE) to prevent experimental ischemic stroke were studied in rats through the permanent occlusion of the middle cerebral artery and common carotid artery for 60 minutes. When the animals were treated with TMB-8, L-arginine, BAEE or NO synthetase inhibitor, nitro-L-arginine at time 0 of ischemia, the areas of neuronal necrosis were reduced by 98%, 99%, 99% and 89%, respectively. When these compounds were administered at 6 hrs after ischemia, the areas of neuronal necrosis were reduced by 91%, 96%, 86% and 81%, respectively. When TMB-8, L-arginine, BAEE or nitro-L-arginine were administered at 24 hours after ischemia, the necrosis areas were reduced less effectively by 80%, 89%, 77% and 60%, respectively. A combination with TMB-8 and L-arginine at time 0, 6 or 24 hr after ischemia resulted in the areas of necrosis being reduced by 99%, 99%, and 89%, respectively. Treatment with the combination of TMB-8 and BAEE at time 0, 6 or 24 hrs after ischemia, resulted in the areas of necrosis being reduced by 99%, 96%, and 82%, respectively. When the drugs were administered at 0 hr of ischemia, L-arginine, BAEE and nitro-L-arginine increased NO synthase activity in the ischemic cortex from 369 +/- 27 of ischemic control to 614 +/- 39, 511 +/- 32 and 406 +/- 16 respectively 1 days after stroke. TMB-8 was a potent agent in reducing intracellular calcium from the base line and blocking the elevation of calcium induced by KCl. The spectrin proteolysis protein, a calcium-activated proteolysis protein was also inhibited by TMB-8 in the ischemic cortex. These results indicated that a combination of TMB-8 and L-arginine is more effective in treating ischemic stroke by simultaneously reducing calcium-activated proteolysis and improving of cerebral blood flow than using TMB-8 or L-arginine alone.

A human case of Stellantchasmus falcatus infection in Korea

In an attempt to find the worm producing unidentified egg, one minute fluke was collect from a Korean patient after praziquantel administration. The fluke was identified to be Stellantchasmus falcatus by the expulsor. Brackish water fish was suggested to be a probable source of the infection.

Expressions of human sodium iodide symporter mRNA in primary and metastatic papillary thyroid carcinomas

The sodium iodide symporter (NIS) is a plasma membrane protein that is responsible for iodide transport into thyroid cells. To understand the regulation and expression of human NIS (hNIS) in papillary thyroid carcinomas, we evaluated the expression levels of hNIS mRNA in primary and lymph node metastatic papillary carcinoma tissues. The correlation of mRNA levels between hNIS and thyroid-specific genes, thyrotropin (TSH) receptor, and thyroglobulin (Tg), were also investigated. Twenty-three cases of papillary carcinoma and 7 pairs of primary and lymph node metastastic tissues were included in this study. We measured the expression levels of hNIS, TSH receptor, and Tg mRNAs by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and RNase protection assay (RPA). The levels of hNIS mRNA in lymph node metastatic tissues were evaluated by RT-PCR. By semiquantitative RT-PCR, 87% of papillary carcinoma (20/23) expressed hNIS mRNA, but the degrees of expression were variable and were lower than those of normal thyroid tissues. The decreased expression of hNIS mRNA in papillary carcinoma compared to normal thyroid tissue was also noticed by RPA. All 23 papillary carcinomas in this study showed the expression of TSH receptor and Tg mRNAs. The levels of TSH receptor mRNA were again lower in papillary thyroid carcinomas than in normal controls. The level of hNIS mRNA was correlated with the levels of TSH receptor (r = 0.449, p < 0.05), but not with Tg mRNA. In addition, significant correlation of mRNA level was observed between TSH receptor and Tg (r = 0.706, p < 0.01). Two of six lymph node metastatic tissues did not show hNIS mRNA even with significant hNIS expressions in papillary carcinoma tissues in thyroid. The levels of hNIS expression of the remaining four lymph node metastatic tissues were lower than those of corresponding primary tissues. Interestingly, one case showed no hNIS expression in primary tissue, but significant hNIS expression in lymph node metastatic tissue. No correlation was found in hNIS mRNA expression between primary and lymph node metastatic tissues. Our results suggest that the measurements of hNIS mRNA level in primary tissues may not predict the therapeutic response to radioactive iodine.

Paragonimus westermani: a cytosolic glutathione S-transferase of a sigma-class in adult stage

We purified cytosolic glutathione S-transferase (GST) of adult Paragonimus westermani monitoring its activity with 1-chloro-2,4-dinitrobenzene (CDNB). The enzyme was purified 18.4-fold to electrophoretic homogeneity with 21% recovery rate through a three-step procedure. The purified enzyme (Pw28GST) has a subunit molecular weight of 28 kDa with an isoelectric point at 4.6. Monoclonal antibody (anti-Pw28GST) against Pw28GST did not cross-react with GSTs from other helminths. cDNA library was constructed in lambdaZAP II bacteriophage and screened with anti-Pw28GST. The corresponding gene containing a single open reading frame of 804 bp encoded 211 amino acids. The predicted amino acid sequence exhibited a higher homology with catalytic domain near N-terminus of class sigma GSTs (58%) than with schistosome 28-kDa GSTs (45-41%) or with class sigma GSTs themselves (33-31%). The sequence contained both Tyr-6 and Tyr-10 that are highly conserved in mammalian and helminth GSTs. The apparent K(m) value of a recombinant enzyme was 0.78 mM. Both native and recombinant enzymes showed the highest activity against CDNB, relatively weak activity against ethacrynic acid and reactive carbonyls, and no activity against epoxy-3-(p-nitrophenoxy)-propane. The activities were inhibited by bromosulfophthalein, cibacron blue, and albendazole, but not by praziquantel. These findings indicate that adult P. westermani has a class sigma GST.

Mini-detachable snare ligation for the treatment of esophageal varices

BACKGROUND

We manufactured and studied the usefulness of a newly designed mini-detachable snare in the treatment of esophageal varices. The use of a multiple rubber band ligator, although generally effective and well tolerated, has certain limitations, including high cost, reduced visual field, and inadvertent band release.

METHODS

We performed a prospective randomized controlled trial of the use of mini-detachable snare ligation vs. multiple band ligation in patients with recent or active esophageal variceal bleeding. The outcomes assessed were immediate hemostasis and rates of recurrent bleeding, eradication, and recurrence.

RESULTS

From March 1997 to October 1998, 103 patients were entered into this trial; 46 underwent mini-detachable snare ligations and 57 multiple band ligations. Among patients with active bleeding, hemostasis was achieved in 6 of 7 (86%) in the mini-detachable snare ligation group and 11 of 13 (85%) in multiple band ligation group. Recurrent bleeding after initial treatment occurred in 2 of 46 (5.5%) in the mini-detachable snare ligation group and 3 of 57 (5.3%) in the multiple band ligation group. Esophageal varices were eradicated or reduced to grade I in 4.8 +/- 2.1 and 4.5 +/- 1.9 sessions in the mini-detachable snare ligation group and multiple band ligation group, respectively. The recurrence rate was 5 of 46 (11%) and 6 of 57 (11%) in the mini-detachable snare ligation group and multiple band ligation group during a follow-up period of 6 and 16 months, respectively. No serious complication occurred in either group.

CONCLUSION

The mini-detachable snare is a new device that provides safe and effective treatment for esophageal varices that is comparable to multiple band ligation.

Toxic effects of mitomycin-C on cultured corneal keratocytes and endothelial cells

Improper use of mitomycin-C in ocular medication may result in damage to corneal cells. In this study, the toxic effects of mitomycin-C on cultured porcine keratocytes and endothelial cells were estimated by MTT, 3H-thymidine uptake and cellular counting assay methods. It was found that mitomycin-C caused a dose-dependent toxic effect to keratocytes and endothelial cells. Both cells were treated with mitomycin-C at the concentration ranging from 100, 10, 1, 0.1 to 0.01 microg/ml for 3 min, 5 min or 100 min. The 50% inhibitory dose (ID50) of mitomycin-C to keratocytes and endothelial cells as measured by MTT assay was 0.40, 0.18, 0.16 mg/ml and 0.27, 0.15, 0.14 mg/ml, respectively, after 3, 5 and 100 minutes drug treatment. The ID50 for keratocytes and endothelial cells as measured by 3H-thymidine uptake immediately, 1 day and 7 days after 100 minutes mitomycin-C treatment was 0.3, 0.0002, 143.2 microg/ml and 45.1, 101.1, 450.2 microg/ml, respectively. The ID50 for keratocytes and endothelial cells as measured by cellular counting 1 day and 7 days after mitomycin-C treatment was 232.5, 109.7 microg/ml and 239.9, 367.5 microg/ml, respectively. It is concluded that mitomycin-C is more toxic to cellular proliferation in cultured corneal keratocytes than in endothelial cells.

Inhibition of quantal release from motor nerve by wortmannin

1. The effects of wortmannin, an inhibitor of phosphatidylinositol (PI) kinases and myosin light chain kinase, on the quantal release of neurotransmitter from mouse phrenic nerve were investigated. 2. Wortmannin (10 - 100 microM) initially enhanced, thereafter progressively depressed spontaneous quantal discharge (miniature endplate potential, mepp). The mean amplitude and the amplitude distribution of mepp were not altered. 3. The compound inhibited and prevented the intensive quantal release evoked by high KC1 solution as well as the mepp burst induced by alpha-latrotoxin, a polypeptide toxin that possesses Ca2+-independent synaptic action to trigger quantal release. The inhibitory actions of wortmannin were partially reversible. 4. Wortmannin depressed the amplitude of endplate potentials (epps) and increased the coefficient of variance of epps. The profile of epps in response to high frequency nerve stimulation exhibited fluctuations between run-down and run-up. The phenomenon is thus different from the consistency of run-up characteristic as the motor nerve Ca2+ channel is blocked by omega-agatoxin IVA. 5. LY294002, another inhibitor of PI 3-kinase, raised mepp frequency without causing late phase suppressions. The compound did not inhibit KC1-, alpha-latrotoxin- or nerve stimulation-evoked quantal release. 6. The results suggest that wortmannin could depress quantal release beyond the step of Ca2+ channel blockade, probably by interfering with the exocytotic cascade.

Pepsin-digested peanut contains T-cell epitopes but no IgE epitopes

BACKGROUND

Peanuts are a common cause of food-induced anaphylaxis and fatalities. Previous studies have demonstrated that rush immunotherapy to crude peanut extract reduces clinical symptoms triggered by oral peanut challenges, but the immunotherapy was associated with an unacceptably high incidence of systemic allergic reactions. One approach to reduce the frequency of allergic reactions would be to use a modified peanut antigen with low allergenic properties.

OBJECTIVE

We sought to determine the immunologic characteristics of crude intact peanut extract before and after pepsin digestion.

METHODS

We used IgE immunoblotting and assessment of T-lymphocyte responses to intact and peptic digests of peanut extracts.

RESULTS

Western blot analysis of sera from 5 subjects with peanut allergy showed multiple IgE-reactive proteins in crude intact peanut extract that were eliminated after pepsin treatment of the peanut extract. In contrast, pepsin-digested peanut induced significant T-cell proliferation responses (stimulation index = 30) in vitro in PBMCs from 7 subjects with peanut allergy, albeit at lower levels than that induced by intact peanut (stimulation index = 66). Furthermore, IFN-gamma production was induced by intact peanut and pepsin-digested peanut in a concentration-dependent manner. Importantly, T-cell lines generated in response to intact peanut also reacted to pepsin-digested peanut, indicating cross-reactive T-cell epitopes in intact and pepsin-digested peanut.

CONCLUSION

These findings suggest that pepsin-digested peanut may be useful in peanut immunotherapy because pepsin digestion eliminates IgE reactivity but maintains T-cell reactivity.

Comparison of fatty acid profiles in the serum of patients with prostate cancer and benign prostatic hyperplasia

OBJECTIVE

The role of dietary fatty acids (FAs) in benign and malignant prostatic diseases was investigated by comparing the composition value of serum fatty acids in the normal controls, and patients with prostate cancer (PC) and benign prostatic hyperplasia (BPH). Also, to estimate a possible association between PC risk and PUFAs, omega-3, omega-6 and omega-3/omega-6 FA composition ratios were compared among these groups.

METHODS

Serum samples were obtained from 24 BPH and 19 PC patients, and from 21 age-matched normal male subjects. The serum concentration of 21 fatty acids was determined using gas chromatography/mass spectrometry.

RESULT

The proportional values of saturated fatty acids (SFAs) groups demonstrated no specific difference between the control subjects and the patients. In the polyunsaturated fatty acids (PUFAs), we found that the omega-3 PUFAs level was significantly decreased in patient with BPH and PC and that the omega-6 PUFAs level was increased in PC only. The ratio of omega-3/omega-6 PUFAs decreased in the following order of normal, BPH, and PC.

CONCLUSION

It was proposed that the changed composition level of PUFAs including omega-3 and omega-6 PUFAs have certain relationship with both prostatic diseases. Therefore, the ratio of omega-3/omega-6 PUFAs also may have an important association with the benign and malignant status of prostatic disease.

Purification of granulin-like polypeptide from the blood-sucking leech, Hirudo nipponia

A cysteine-rich (approximately 20%), low molecular weight (MW 6 kDa) polypeptide has been isolated from the Korean blood-sucking leech, Hirudo nipponia. From its amino acid composition and N-terminal amino acid sequence analysis, the new protein is similar to granulin (or epithelin), and so it has been named leech granulin. The leech granulin behaved as a thrombin inhibitor in the purification steps of size-exclusion, ion-exchange, chromatofocusing, and reverse-phase high-performance liquid chromatography. The leech granulin is an acidic peptide (pI 3.75) containing high cysteine residues with a unique sequence similar to granulins or epithelins isolated from other organisms. For the first time, a granulin-like polypeptide having thrombin inhibitory activity has been isolated from a leech species.

Transesophageal echocardiographic detection of thoracic aortic plaque could noninvasively predict significant obstructive coronary artery disease

OBJECTIVE

Previous pathologic and roentgenographic studies have suggested a relation between aortic plaque and coronary artery disease but have lacked clinical utility. The study was undertaken to elucidate whether atherosclerotic aortic plaque detected by transesophageal echocardiography can be a clinically useful marker for significant obstructive coronary artery disease.

METHODS

Clinical and angiographic features and intraoperative transesophageal echocardiographic findings were prospectively analyzed in 131 consecutive patients (58 women and 73 men, aged 17 to 75 years [mean 54 +/- 12]) undergoing open heart surgery. Significant obstructive coronary artery disease was defined as > or = 50% stenosis of > or = 1 major branch.

RESULTS

Seventy-six (58%) of 131 patients were found to have obstructive coronary artery disease. In 76 patients with significant coronary artery disease, 71 had thoracic aortic plaque. In contrast, aortic plaque existed in only 10 of the remaining 55 patients with normal or minimally abnormal coronary arteries. The presence of aortic plaque on transesophageal echocardiographic studies had a sensitivity of 93%, a specificity of 82% and positive and negative predictive values of 88% and 90%, respectively, for significant coronary artery disease. There was a significant relationship between the degree of aortic intimal changes and the severity of coronary artery disease (r = 0.74, P < 0.0001). Multivariate logistic regression analysis of patient age, sex, risk factors of cardiovascular disease and transesophageal, echocardiographic findings revealed that atherosclerotic aortic plaque was the most significant independent predictor of coronary artery disease.

CONCLUSION

This study indicates that transesophageal echocardiographic detection of atherosclerotic plaque in the thoracic aorta is useful in the noninvasive prediction of the presence and severity of coronary artery disease.

A case of Strongyloides stercoralis infection

Strongyloidiasis has been recognized as one of the life-threatening parasitic infections in the immunocompromised patients. We report an intestinal infection case of Strongyloides stercoralis in a 61-year-old man. Rhabditiform larvae were detected in the stool examination and developed to filariform larvae having a notched tail through the Harada-Mori filter paper culture. The patient received five courses of albendazole therapy but not cured of strongyloidiasis.

Isoeugenolol: a selective beta1-adrenergic antagonist with tracheal and vascular smooth muscle relaxant properties

Isoeugenolol (1.0, 3.0, 5.0 mg/kg, i.v.) produced a dose-dependent bradycardia and a decrease in blood pressure in anesthetized Wistar rats. Isoeugenolol inhibited the tachycardia effects induced by (-)isoproterenol, but had no blocking effect on the arterial pressor responses induced by (-)phenylephrine. In isolated guinea pig tissues, isoeugenolol antagonized (-)isoproterenol-induced positive inotropic and chronotropic effects on the atria and tracheal relaxations in a concentration-dependent manner. The apparent pA2 values for isoeugenolol on right atria, left atria and trachea were 7.63+/-0.03, 7.89+/-0.12 and 6.12+/-0.05, respectively, indicating that isoeugenolol was a highly selective beta1-adrenoceptor blocker. On the other hand, isoeugenolol produced a mild direct cardiac depression at high concentration and was without intrinsic sympathomimetic activity (ISA). In isolated rat thoracic aorta, isoeugenolol relaxed more potently the contractions induced by (-)phenylephrine (10 microM) and 5-HT (10 microM) than those by high K+ (75 mM). In isolated guinea pig trachea, isoeugenolol attenuated the carbachol (1 microM)-con-tracted trachea more significantly than those contracted with high K+. Furthermore, the binding characteristics of isoeugenolol and various beta-adrenoceptor antagonists were evaluated in [3H]CGP-12177 binding to rat ventricle, lung and interscapular brown adipose tissue (IBAT) membranes. The -log IC50 values of isoeugenolol for predominate beta1-, beta2- and beta3-adrenergic receptor sites were 5.82+/-0.09, 4.74+/-0.05 and 4.73+/-0.12, respectively. In conclusion, isoeugenolol was found to be a highly selective beta1-adrenoceptor antagonist with tracheal and vascular smooth muscle relaxant activities, but was devoid of alpha-adrenoceptor-blocking action.

Infection status of dragonflies with Plagiorchis muris metacercariae in Korea

Plagiorchis muris has been found in both house and field rats as well as in humans. The infection status of the second intermediate hosts of P. muris is prerequisite in understanding their biological features in an ecosystem. Six species of dragonflies were caught in a wide range of areas in Korea; and they were Sympetrum darwinianum, S. eroticum, S. pedomontanum, S. infuscatum, Pantala flavoscens, Calopteryx atrata, and Orthetrum albistylum speciosum. The occurrence of P. muris metacercariae in dragonflies was nationwide with various infection rates. The metacercarial burden of P. muris in the surveyed areas was the highest in S. eroticum followed by S. darwinianum, S. pedomontanum, and C. atrata. The highest infection rate by P. muris metacercariae was found in S. darwinianum followed by S. eroticum. The metacercarial burden was particularly heavy in the dragonflies found in Hamyang-gun and Kosong-gun, Kyongsangnam-do. It is, therefore, likely that dragonflies play a significant role as the second intermediate host in the life cycle of P. muris in Korea.

The loss of expression of transforming growth factor-beta receptors correlates with the histopathologic tumor grade in bladder transitional cell carcinoma patients

Transforming growth factor-beta (TGF-beta), a pleiotropic growth factor, is a potent inhibitor of cellular proliferation in cells of epithelial origin. Recently, it has been suggested that a loss of sensitivity to TGF-beta through a loss of expression of TGF-beta receptors T beta R-I and T beta R-II--is associated with tumor initiation and progression. Therefore, to investigate the relationship between TGF-beta receptors expression and carcinogenesis of bladder TCC, this study examined the expression of T beta R-I and T beta R-II in 46 bladder TCC patients using immunohistochemistry. Since histopathological grade is a widely accepted marker of prognosis, the results were compared in relation to the three grades of bladder TCC. The results demonstrated that the loss of TGF-beta receptors expression is associated with increasing histopathological grades of bladder TCC. Specifically, both T beta R-I and T beta R-II were readily detected in all 10 normal bladder mucosa specimens. Likewise, all 6 specimens of grade I TCC samples expressed high levels of both TGF-beta receptors. However, among grade II TCC samples, T beta R-I and T beta R-II were detected in 78% and 89%, respectively: among grade III TCC samples, T beta R-I and T beta R-II were detected in 45% and 41%, respectively. These results suggested that loss of sensitivity to TGF-beta may play a role in the progression of TCC from low to high grade disease.

Evaluation of intrinsic modulation of synaptic transmission by ATP in mouse fast twitch muscle

This study aims to evaluate whether endogenous ATP or adenosine modulates the neurotransmission and contractile function of mouse phrenic nerve-diaphragm. Bath application of ATP (1 mM) and alpha, beta-methylene ATP (m-ATP, 0.1 mM) elevated muscle tones, depressed contractions (approximately 12%), and depolarized muscle membranes (approximately 20 mV). Adenosine (1 mM) or low concentrations of ATP (0.1 mM) had no effect. In a low Ca2+ media, ATP caused prolonged inhibitions of endplate potentials (EPPs), whereas m-ATP augmented EPPs while both agents produced slight effects in normal Tyrode solution. When applied by puff ejection, ATP and m-ATP additionally elicited fast transient suppressions of EPPs in association with inhibitions of high K+-evoked releases of miniature EPPs. Blockades of P2 purinoceptors with suramin antagonized all the effects of ATP and m-ATP except the prolonged inhibitions of EPPs induced by ATP, which were antagonized instead by 8-cyclopentyl-1,3-dipropylxanthine (CPDPX), an A1 adenosine receptor antagonist. Suramin and CPDPX did not change contractions nor alter EPPs evoked by a low- or high-frequency nerve stimulation. The results indicate that exogenously applied ATP and m-ATP, via activations of distinct pre- and postsynaptic purinoceptors, exert inhibitory and facilitatory pharmacological modulations on the mature neuromuscular junction. However, because of intrinsic high efficiency of the synaptic transmission under physiological conditions, endogenously released ATP and its degradation product-adenosine-do not build up to concentrations high enough to alter motor functions.

Effects of Intracellular Calcium Reduction by Dantrolene on Prevention/Treatment of Ischemic Stroke

BACKGROUND: It has been suggested that cerebral blood vessels and brain cells might depend more on intracellular calcium than extracellular calcium to modulate intracellular free calcium concentrations, [Ca(2+)](i). METHODS AND RESULTS: A potent intracellular calcium antagonist, dantrolene, was used to prevent the ischemic stroke induced in the rat model. It was found that treatment of rats with dantrolene at -1 hour and +1 hour after 60 minutes of ischemic insult prevented by the formation of cortical necrosis 98% and 85%, respectively. Further, the [Ca(2+)](i) of embryonic aorta cells was markedly reduced, and cAMP of the same cultured cells were significantly increased by dantrolene treatment. CONCLUSIONS: These results indicate that ischemic stroke is preventable by dantrolene through reduction of [Ca(2+)](i) and increase of cAMP.

Dexon and nylon-sutured wound reaction in conjunctival flap after trabeculectomy combined with or without topical application of mitomycin-C

In this study, rabbits were used to evaluate the sutured wound reaction with Dexon or nylon in the conjunctival flap 1, 4, 7, 14 and 28 days after trabeculectomy surgery with or without the use of mitomycin-C. Four major treated groups were used to compare their wound healing reaction; group 1--nylon-suture and non-mitomycin treatment; group 2--nylon-suture and mitomycin treatment; group 3--Dexon-suture and non-mitomycin treatment; group 4--Dexon-suture and mitomycin treatment. One day after surgery, the number of polymorphs was the greatest most in the nylon-sutured and non-mitomycin treated tissues (86 +/- 2). Four days after surgery, the number of polymorphs was the greatest most in Dexon-sutured and non-mitomycin treated tissues (109 +/- 87). The number of fibroblasts was the greatest most in nylon-sutured and non-mitomycin treated tissues (111 +/- 23). Seven days after surgery, the number of polymorphs was the greatest most in Dexon-sutured and mitomycin treated tissues (32 +/- 12). The number of fibroblasts was the greatest most in nylon-sutured and non-mitomycin treated tissues (126 +/- 15). Fourteen days after surgery, the number of fibroblasts was the greatest most in Dexon-sutured and non-mitomycin tissues (43 +/- 10). The number of goblet cells was the greatest most in nylon-sutured and non-mitomycin treated tissues (4 +/- 2). Twenty-eight days after surgery, the number of fibroblasts was the greatest most in Dexon-sutured and mitomycin treated tissues (40 +/- 15). The number of goblet cells was the greatest most in nylon-sutured and non-mitomycin treated tissues (4 +/- 2). Our conclusions are as follows: 1). The concentration of mitomycin in conjunctival wound edge should be maintained at as low a level as possible because the mitomycin will delay the wound healing process; 2). Nylon material is better than Dexon for conjunctival wound suture because nylon could induce a great quantity of fibroblasts before Dexon did.

Prevalences of Gs alpha, ras, p53 mutations and ret/PTC rearrangement in differentiated thyroid tumours in a Korean population

OBJECTIVE

In thyroid tumours, ras, Gs alpha, p53 mutations and ret/PTC rearrangement have been reported with variable prevalences in different geographical regions. We studied the prevalence of these mutations and rearrangement in thyroid tumours in a Korean population. As MDM2 and Bcl-1 protein expressions have been suggested to be associated with p53 protein, we also studied possible relationships among them.

PATIENTS AND DESIGN

Eleven cases of adenomatous goitre, eight cases of follicular adenoma, five cases of follicular carcinoma and 37 cases of papillary carcinoma were included in this study. To find mutations and rearrangement, RT-PCR, SSCP and/or direct sequencing, after subcloning if necessary, were used, and immunohistochemical stainings were performed for p53, MDM2 and Bcl-2 proteins in cases of papillary carcinoma.

RESULTS

We could not find any rearrangement for ret/PTC-1, -2, -3 and mutation of Gs alpha. For the ras oncogene, K and H-ras mutations were not found, but N-ras mutations, point mutation of CAA to CGA in codon 61, were detected in one follicular adenoma (12.5%, 1/8) and one follicular carcinoma (33%, 1/3). p53 mutations were detected in only one case of papillary carcinoma (3%, 1/31: exon 8, codon 266 GGA-->GAA). In 30 cases of papillary carcinoma without p53 mutation, the prevalences of positive immunohistochemical staining were 13.3% for p53 protein, 53.3% for MDM2 protein and 56.7% for Bcl-2 protein. While over-expression of p53 protein was not significantly related to that of MDM2 and Bcl-2 proteins, over-expression of MDM2 and Bcl-2 in papillary carcinoma were associated.

CONCLUSION

ret/PTC rearrangement, Gs alpha, ras and p53 mutations are relatively rare in differentiated thyroid neoplasms from a Korean population, which may reflect genetic and environmental differences from patients in countries with high prevalences. P53 protein over-expression was noted in 13.3% of papillary carcinoma cases without p53 mutation and was not significantly related to MDM2 and Bcl-2 expression.

Surface ultrastructure of juvenile and adult stages of Centrocestus armatus

Centrocestus armatus (Trematoda: Heterophyidae) develops rapidly and produces eggs at 3 days postinfection in albino rats. Excysted metacercariae are pear-shaped and concave ventrally, with 42-44 peg-like circumoral spines. The entire body surface is densely covered with scale-like serrated spines. On juveniles, serration of the tegumental spines is greatest in the middle of the ventral and dorsal surfaces, and decreases anteriorly and posteriorly. Ciliated sensory papillae are concentrated around the oral sucker. Several nonciliated sensory papillae (type II papillae) occur equidistantly on the acetabulum and are arranged in a linear symmetry on the dorsal surface. On adults, the serration of the tegumental spines decreases to 14-17 tips on the ventrolateral surface. The high density of tegumental spines on posterior half of the body and the distribution of type II papillae on dorsal surface are considered to be characteristic of C. armatus.

Plagiorchis muris: recovery, growth and development in albino rats

Metacercariae of Plagiorchis muris, obtained from naturally infected dragonflies, Sympetrum eroticum, successfully established in 4-week-old albino rats up to 14 days post-infection (p.i.) but by day 28 p.i. the recovery rate had significantly decreased. The genital primordia in excysted metacercariae were differentiated into those of metraterm, Mehlis' gland, ovary and cirrus pouch, with the primordial testes appearing on day 1 p.i. The vitellaria and eggs in the uterus were present in flukes on days 2 and 4 p.i., respectively. Mature flukes were established in the lower part of the small intestine on day 5 p.i., with the peak of egg production occurring on day 14 p.i. Growth of the flukes continued up to day 28 p.i.

Calcium-induced changes on crystallins in organ-cultured porcine lens

In this study, intact porcine lenses were cultured in vitro for 7 days supplemented with commercial balanced salt solution (BSS) which is usually used as an irrigation solution during intraocular surgery, and the lenses were maintained under various culture conditions, e.g. temperature and CO2 concentration. The intact porcine lenses after 7 days culture were analyzed with optical density scanner, gel permeation chromatography on TSK HM-55 column and SDS-PAGE (polyacrylamide gel electrophoresis). It was found that lenses exhibited the least opacity when lenses were cultured with Ca(+2)-free BSS buffer, CO2-free incubator and maintained at a temperature of 25 degrees C. After the lenses were cultured with Ca(+2)-free BSS or BSS medium, the composition of crystallins in lenses was separated with TSK HM-55 column. It was indicated that the percentage of high molecular weight (HMW) protein and (alpha-crystallin increased, and gamma-crystallin decreased in lenses incubated with BSS medium compared with lenses incubated with Ca(+2)-free BSS medium. Following an increase in the concentration of calcium in the medium from 4.3 mM, 20 mM, 50 mM, 100 mM to 200 mM, the opacity of the lens was measured with a densitometer. The changed percentage of various crystallins was similar to lenses with BSS media that increased in HMW protein and alpha-crystallin, decreasing in gamma-crystallin. In the case of lens protein pattern, the crystallin washed from TSK HM-55 gel was separated with SDS-PAGE (polyacrylamide gel electrophoresis). It was indicated that some of proteins disappeared when lenses were incubated with various concentrations of calcium. The vanished pH proteins were 20.5 kDa at 50 mM calcium, 20.5 kDa and 21 kDa at 100 mM, 20.5 kDa, 21 kDa, 22 kDa and 23 kDa at 200 mM which were compared with the protein bands in the presence of 20 mM calcium in BSS medium. This study indicates that the commercial balanced salt solution (BSS) which is usually used as an irrigating solution during intraocular operations may increase the risk for lens opacity because of the calcium contained in the solution.

Isolation of an extragenic suppressor of the rna1-1 mutation in Saccharomyces cerevisiae

The small GTPase Ran is essential for nucleocytoplasmic transport of macromolecules. In the yeast Saccharomyces cerevisiae, Rna1p functions as a Ran-GTPase activating protein (RanGAP1). Strains carrying the rna1-1 mutation exhibit defects in nuclear transport and, as a consequence, accumulate precursor tRNAs. We have isolated two recessive suppressors of the rna1-1 mutation. Further characterization of one of the suppressor mutations, srn10-1, reveals that the mutation (i) can not bypass the need for Rna1p function and (ii) suppresses the accumulation of unspliced pre-tRNA caused by rna1-1. The SRN10 gene is not essential for cell viability and encodes an acidic protein (pI = 5.27) of 24.8 kDa. Srn10p is located in the cytoplasm, as determined by indirect immunofluorescence microscopy. Two-hybrid analysis reveals that there is a physical interaction between Srn10p and Rna1p in vivo. Our results identify a protein that interacts with the yeast RanGAP1.

Novel inhibition of contractility by wortmannin in skeletal muscle

1. The effects of wortmannin and 2-(4-morpholinyl)-8-phenyl-1[4H]-benzopyran-4-one (LY294002), inhibitors of phosphatidylinositol 3-kinase, on the contractile responses of murine skeletal muscle were studied. Wortmannin (10-100 microM) suppressed twitch and tetanic contraction evoked by field stimulation of diaphragm without causing elevation of muscle tone. The inhibition was quasi-irreversible with IC50 approximately 15 microM. In contrast, LY294002 increased twitch responses and elevated muscle tone. 2. Wortmannin reversibly depressed the maximal slope of action potential upstroke by approximately 40% and inhibited the membrane depolarization and spontaneous burst of action potential induced by crotamine, a polypeptide toxin that activates the Na+ channel of skeletal muscle. 3. Wortmannin inhibited contractures evoked by high K+, ryanodine and caffeine, but potentiated the contracture induced by rapamycin, which binds to myoplasmic FK506 binding protein, an immunophilin closely associated with the ryanodine receptor. The contractures elicited by cardiotoxin, which disrupts the integrity of sarcolemma and thereby elevates 'myoplasmic' Ca2+ level, were suppressed only slightly. 4. In placed left atrium and ventricular strip, wortmannin and LY294002 produced a positive inotropic effect. 5. The results suggest that, in addition to depressing the Ca2+ mobilization from sarcoplasmic reticulum, wortmannin exerts a novel inhibitory action on the excitation-contraction coupling in skeletal muscle but not in cardiac muscle.

Ocular hypotensive and vasodilative effects of two beta-adrenergic blockers with intrinsic sympathomimetic activity

PURPOSE

The ocular hypotensive and vasodilative effects of vaninolol and eugenolol, two beta-adrenergic blockers with intrinsic sympathomimetic activity, were tested in rabbits and their pharmacologic mechanisms were also studied in vitro.

METHODS

Intraocular pressure was measured in ocular hypertonic rabbits which were induced by infusing 20% NaCl or 5% glucose solution. The rabbit's ocular blood flow was determined using the colored microsphere technique. The concentrations of cAMP were evaluated in porcine ciliary body and cultured A7r5 smooth muscle cells by radioimmunoassay. Ca+2 concentration was measured in A7r5 cells by spectrofluorometry after loading cells with Fura-2-AM.

RESULTS

It was found that 0.5% eugenolol and vaninolol could suppress the intraocular pressure in glucose-induced ocular hypertensive rabbits and delay the intraocular pressure recovery in NaCl-induced ocular hypertensive rabbits. In addition, both agents improved the ocular blood flow in the iris, ciliary body, retina and choroid. Vaninolol and eugenolol of 10 microM inhibited the basal cAMP accumulation from 23.9 +/- 2.0 of control to 8.7 +/- 0.4 and 2.4 +/- 0.1 respectively and inhibited the isoproterenol-induced cAMP accumulation from 154.3 +/- 13.6 to 120.6 +/- 8.3 and 74.2 +/- 6.1 respectively in the porcine ciliary body. The cellular cAMP concentration was significantly increased from 10 +/- 1 of control to 96 +/- 5 (vaninolol) and 38 +/- 3 (eugenolol) in cultured A7r5 smooth muscle cells. Both agents also increased the intracellular calcium concentration in A7r5 cells.

CONCLUSIONS

These results indicate that the lowering of intraocular pressure by vaninolol and eugenolol may be due to cAMP suppression in the ciliary body by beta-antagonist and/or alpha2-agonist activities. Both agents cause vasodilation via beta2-agonist action that increase the smooth muscle cellular cAMP level more than vasoconstriction via alpha-agonist activity by increasing an influx of extracellular Ca+2.

A highly selective beta1-adrenergic blocker with partial beta2-agonist activity derived from ferulic acid, an active component of Ligusticum wallichii Franch

Short-term injection of ferulinolol (0.1, 0.5, and 1.0 mg/kg, i.v.) produced dose-dependent bradycardia responses in pentobarbital-anesthetized Wistar rats, whereas it had no significant effects on the blood pressure. Ferulinolol markedly inhibited the tachycardia effects induced by (-)isoproterenol but did not show any blocking effect on the arterial pressor responses induced by (-)phenylephrine. These findings clearly suggested that ferulinolol had a beta-adrenergic blocking activity; nevertheless, it did not involve an alpha-adrenergic blocking action. In isolated guinea pig tissues, ferulinolol competitively antagonized (-)isoproterenol-induced positive inotropic and chronotropic effects of the atria and tracheal relaxation responses. The parallel shift to the right of the concentration-response curve of (-)isoproterenol suggested that ferulinolol was a beta-adrenoceptor-competitive antagonist. The apparent pA2 values for ferulinolol on right atria, left atria, and trachea were 7.62 +/- 0.05, 7.54 +/- 0.01, and 6.28 +/- 0.11, respectively. Ferulinolol was more potent on the atria than on tracheal tissues, demonstrating that it possessed beta1-adrenoceptor selectivity. The intrinsic sympathomimetic activity (ISA) of ferulinolol and propranolol were determined on isolated atria and trachea from reserpine-treated guinea pig. Propranolol caused significantly negative inotropic and chronotropic effects at > or =1 microM, whereas ferulinolol possessed fewer cardiodepressant activities than propranolol. In reserpine-treated tracheal strips, ferulinolol produced dose-dependent relaxant responses, but propranolol was without effectiveness. Preincubating the preparations with ICI 118,551 (0.1, 1.0, and 10 nM), a beta2-adrenoceptor antagonist, significantly shifted the concentration-relaxation curves of ferulinolol to a region of higher concentrations. These results implied that ferulinolol had a partial beta2-agonist activity. Further, binding characteristics of ferulinolol and various beta-adrenoceptor antagonists were evaluated in [3H]CGP-12177 binding to rat ventricular or lung membranes. The Ki values of ferulinolol, atenolol, metoprolol, and (-)propranolol were 103, 262, 123, and 0.23 nM, respectively, in ventricular membranes, and 2,412, 7,539, 2,186, and 0.72 nM, respectively, in lung membranes. In conclusion, ferulinolol was found to be a highly selective beta1-adrenoceptor antagonist with partial beta2-agonist activity but was devoid of alpha-adrenoceptor blocking action.

Telomerase: a potential marker of bladder transitional cell carcinoma in bladder washes

Telomerase is an enzyme that immortalizes cells by maintaining a constant telomere length. Here, telomerase activity in bladder washes was analyzed and compared with the final pathological diagnosis in 23 patients with bladder transitional cell carcinoma (TCC). Bladder washes and normal tissues were obtained from each patient prior to transurethral resection of bladder tumor. Telomerase activity was detected using telomeric repeat amplification protocol assay based on PCR. Cytological diagnosis of centrifuged cells from bladder washes was made using Papanicolau's stain. Results demonstrated that telomerase activity was detected in 95.7% of both cancer tissues and bladder washes. In normal tissues, telomerase activity was not detected in 22 of 23 samples. Regarding cytological diagnosis, only 69.6% of bladder wash samples had positive cytology. Moreover, in five cases of grade 1 TCC, only 20% of the cytological specimens were positive for malignancy, whereas 80% showed positive telomerase activity. These results demonstrate that telomerase activity is detectable in a majority of human bladder cancer tissues and bladder washes obtained from patients with TCC. In addition, results of this study suggest that the presence of telomerase in bladder washes may be a specific marker of bladder cancer, especially in low-grade tumors.

Benzodiazepines differentially inhibit phenylephrine-induced calcium oscillations in pulmonary artery smooth muscle cells

BACKGROUND

Modulation of intracellular free calcium is a critical determinant of vasomotor tone. The authors investigated the effects of three benzodiazepines on alpha-adrenergic-induced oscillations in intracellular free calcium in individual pulmonary artery smooth muscle cells.

METHODS

Pulmonary artery smooth muscle cells were cultured from explants of canine intrapulmonary artery. Fura-2-loaded pulmonary artery smooth muscle cells were continuously superfused with phenylephrine (10 microM) at 37 degrees C on the stage of an inverted fluorescence microscope. Intracellular free calcium was measured using a dual wavelength spectrofluorometer. After establishment of steady-state intracellular free calcium oscillations induced by phenylephrine, lorazepam, diazepam, or midazolam was added to the superfusate. The amplitude and frequency of the intracellular free calcium oscillations were compared before and after addition of each agent.

RESULTS

Resting mean +/- SEM values of intracellular free calcium were 68 +/- 8 nM. Phenylephrine stimulated dose-dependent oscillations in intracellular free calcium, which reached a peak concentration of 676 +/- 35 nM and a frequency of 1.08 +/- 0.1 transients/min. Addition of lorazepam (1 microM) inhibited (P < 0.05) the amplitude (591 +/- 32 nM) but not the frequency (0.97 +/- 0.1 transients/min) of the oscillations. Conversely, diazepam (1 microM) decreased (P < 0.05) the frequency (0.79 +/- 0.1 transients/min) but not the amplitude (663 +/- 37 nM) of the oscillations. These effects were dose-dependent. In contrast, midazolam (1-30 microM) had no effect on the amplitude or frequency of intracellular free calcium oscillations. At concentrations higher than 100 microM, however, all three benzodiazepines inhibited both the amplitude and frequency of the intracellular free calcium oscillations.

CONCLUSION

Lorazepam and diazepam but not midazolam exerted differential inhibitory effects on phenylephrine-induced intracellular free calcium oscillations. Benzodiazepines may alter the pulmonary vascular response to sympathetic alpha-adrenoreceptor activation by direct inhibition of intracellular free calcium signaling in pulmonary artery smooth muscle cells.

Inhibition of protein synthesis by nitric oxide correlates with cytostatic activity: nitric oxide induces phosphorylation of initiation factor eIF-2 alpha

BACKGROUND

Nitric oxide (NO) is cytostatic for proliferating cells, inhibits microbial growth, and down-regulates the synthesis of specific proteins. Studies were undertaken to determine the mechanism by which NO inhibits total protein synthesis and whether the inhibition correlates with established cytostatic activities of NO.

MATERIALS AND METHODS

In in vitro experiments, various cell types were exposed to NO using either donors or expression of inducible NO synthase (iNOS). The capacity of NO to suppress total protein synthesis, measured by incorporation of 35S-methionine into protein, was correlated with the capacity of NO to suppress cell proliferation, viral replication, or iNOS expression. Phosphorylation of eIF-2 alpha was examined as a possible mechanism for the suppressed protein synthesis by NO.

RESULTS

Both NO donors and expression of the iNOS suppressed total protein synthesis in L929 cells and A2008 human ovarian tumor cells in parallel with decreased cell proliferation. Suppressed protein synthesis was also shown to correlate with decreased vaccinia virus proliferation in murine peritoneal macrophages in an iNOS-dependent manner. Furthermore, iNOS expression in pancreatic islets or RAW264.7 cells almost completely inhibited total protein synthesis, suggesting that nonspecific inhibition of protein synthesis may be the mechanism by which NO inhibited the synthesis of specific proteins such as insulin or iNOS itself. This possibility was confirmed in RAW264.7 cells where the inhibition of total protein synthesis correlated with the decreased iNOS protein. The decrease in protein levels occurred without changes in iNOS mRNA levels, implicating an inhibition of translation. Mechanistic studies revealed that iNOS expression in RAW264.7 cells resulted in the phosphorylation of eIF-2 alpha and inhibition of the 80S ribosomal complex formation.

CONCLUSIONS

These results suggest that NO suppresses protein synthesis by stimulating the phosphorylation of eIF-2 alpha. Furthermore, our observations indicate that nonspecific inhibition of protein synthesis may be a generalized response of cells exposed to high levels of NO and that inhibition of protein synthesis may contribute to many of the described cytostatic actions of NO.

Intracellular translocation of PKC isoforms in canine pulmonary artery smooth muscle cells by ANG II

Our goals were to identify the isoforms of protein kinase C (PKC) present in primary cultures of canine pulmonary artery smooth muscle cells (PASMCs) and to determine whether angiotensin II (ANG II) triggers translocation of specific PKC isoforms to discreet intracellular locations. Isoform-specific antibodies and Western blot analysis were utilized to identify the isoforms of PKC in PASMCs. Indirect immunofluorescence and confocal microscopy were used to examine the subcellular distribution of PKC isoforms. Inositol phosphate production was used to assess phospholipase C activation, and fura 2 was utilized to monitor intracellular Ca2+ concentration in response to ANG II. Six isoforms (alpha, delta, epsilon, zeta, iota/lambda, and mu) of PKC were identified by Western blot analysis. Immunolocalization of 5 isoforms (alpha, delta, zeta, iota/lambda, and mu) revealed a unique pattern of staining for each individual isoform. ANG II caused translocation of PKC-alpha from the cytosol to the nuclear envelope and of PKC-delta to the myofilaments. In contrast, cytosolic PKC-zeta did not translocate, but nuclear PKC-zeta was upregulated. Translocation of PKC-alpha and PKC-delta and upregulation of PKC-zeta in response to ANG II were blocked by the ANG II type 1-receptor antagonist losartan. In addition, ANG II stimulated inositol phosphate production and intracellular Ca2+ concentration oscillations, which were blocked by losartan. Thus activation of ANG II type 1 receptors triggers the phosphoinositide signaling cascade, resulting in translocation or upregulation of specific PKC isoforms at discreet intracellular sites. The alpha and zeta isoforms may act to regulate nuclear events, whereas PKC-delta may be involved in modulating contraction via actions on the myofilaments.

Halogenated aromatic hydrocarbons suppress CA1 field excitatory postsynaptic potentials in rat hippocampal slices

Halogenated aromatic hydrocarbons (HAHs), such as polychlorinated biphenyls (PCBs) and dibenzo-p-dioxins (PCDDs), alter cognitive function and learning. The cellular basis of HAH-induced alteration of brain function is not well-understood. The hippocampus is a likely site of toxic action because of its well-known roles in learning and memory, as well as its propensity to accumulate environmental neurotoxicants. A hippocampal function that can be measured readily is evoked excitatory postsynaptic potentials (EPSPs), which are an index of excitatory synaptic function. In this study, effects of HAHs on EPSPs were characterized in hippocampal slices from adolescent to adult male Sprague-Dawley rats. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and 1,2,3,4-TCDD were used because these HAHs are prototypical potent and weak aryl hydrocarbon (Ah) receptor agonists, respectively. 2,2',5,5'-Tetrachlorobiphenyl (TCB) was used as a prototypical ortho-substituted PCB, which acts through Ah receptor-independent pathways. For each hippocampal slice, peak amplitudes of EPSPs during a 15-min recording period (1 recording/min) were averaged and used as baseline (100%). Subsequent EPSPs were expressed as percentage of baseline. TCDD and 1,2,3,4-TCDD did not alter EPSPs in slices from the middle third of the hippocampus. However, in ventral slices, TCDD significantly decreased EPSPs, whereas 1,2,3,4-TCDD was inactive. TCB decreased EPSPs in both middle and ventral slices at half-maximal stimulation. An unexpected reversal of inhibition was observed within 30 min of continuous application of TCDD or TCB. In ventral slices, L-type calcium channel blocker nifedipine blocked inhibition of EPSPs induced by TCDD but not EPSPs inhibited by TCB. These results suggest that, while TCB-induced inhibition of EPSPs occurs through an unknown mechanism, TCDD-induced inhibition of EPSPs was mediated by L-type calcium channel activity in a congener-specific manner.

Phenylephrine-induced Ca2+ oscillations in canine pulmonary artery smooth muscle cells

Modulation of [Ca2+]i in response to receptor activation is a critical determinant of vascular smooth muscle tone. In this study, we examined the effect of continuous stimulation of alpha 1-adrenoceptors with phenylephrine (PE) on [Ca2+]i in single pulmonary artery smooth muscle cells (PASMCs) cultured from explants of canine intrapulmonary artery. Fura 2-loaded PASMCs pretreated with propranolol (5 mumol/L) were continuously superfused with PE at 37 degrees C on the stage of an inverted fluorescence microscope, and [Ca2+]i was measured using a dual-wavelength spectrofluorometer. Resting values of [Ca2+]i were 96 +/- 4 nmol/L. PE (10 mumol/L) stimulated oscillations in [Ca2+]i at a frequency of 1.35 +/- 0.07/min, which reached a peak [Ca2+]i of 650 +/- 26 nmol/L (n = 69 cells). The oscillations lasted for > 30 minutes and were constant in amplitude and frequency. Both the amplitude and frequency of PE-induced [Ca2+]i oscillations increased in a dose-dependent (3 x 10(-8) to 10(-4) mol/L) manner. Pretreatment with the alpha 1-adrenoceptor antagonist prazosin (50 nmol/L) or removal of extracellular Ca2+ abolished the repetitive [Ca2+]i oscillations induced by PE. The voltage-operated Ca2+ channel blockers nifedipine (1 mumol/L) and verapamil (1 mumol/L) had no effect on the [Ca2+]i oscillations. In contrast, inhibition of phospholipase C with U73122 (10(-7) to 10(-5) mol/L) attenuated the oscillations in a dose-dependent fashion. The nonselective protein kinase inhibitor staurosporine (10(-9) to 10(-7) mol/L) had a minimal inhibitory effect on the oscillations. Caffeine (30 mmol/L) and thapsigargin (1 mumol/L) abolished the oscillations, whereas pretreatment with ryanodine (1 to 100 mumol/L) had no effect. In freshly dispersed PASMCs, PE (10 mumol/L) induced oscillations in [Ca2+]i similar to those observed in cultured cells, and patch-clamp experiments revealed oscillations in membrane potential. These results indicate that PE induces [Ca2+]i oscillations in PASMCs via stimulation of alpha 1-adrenoceptors coupled to phospholipase C activation. Voltage-operated Ca2+ channels and protein kinases are not required for the oscillations. The requirement for extracellular Ca2+ and intracellular Ca2+ stores indicates that both Ca2+ influx and intracellular Ca2+ release play a role in the maintenance of the oscillations.

Trauma-induced changes of skeletal muscle membrane: decreased K+ and increased Na+ permeability

Trauma of skeletal muscle causes membrane depolarization and reduces membrane resistance. The underlying mechanisms were studied in isolated mouse phrenic nerve diaphragms subject to sharp transections of muscle. Depolarization was most marked at the vicinity ( approximately 1 mm) of trauma, where the membrane potential dropped rapidly from about -80 mV to zero and repolarized to about -25 mV. At the end-plate region (located approximately 3 mm away from the cut end), the membrane gradually attained a plateau potential around -45 mV. The magnitude of depolarization was not reduced by inhibition of Na+, Ca2+, or Cl- channel, whereas the progress of depolarization was delayed in low-Na+ medium. Activation of the K+ channel with lemakalim induced some hyperpolarization at damaged site but produced a glybenclamide-sensitive outward current and hyperpolarization of end-plate region to the levels before trauma, as if there was no diminution of transmembrane K+ gradient in this area. Appropriate elevation of extracellular K+ to stimulate K+ conductance also hyperpolarized the end-plate region. The results suggest that depolarization at regions remote from trauma is related to decreased K+ and increased Na+ permeability. The cytoplasma compartmentalization and permeability changes may protect muscle fiber from trauma.

Alteration of glucose uptake in cultured human corneal endothelial cells grown in high glucose media via cAMP-dependent pathway

In this study, cultured human corneal endothelial cells were incubated in media containing various concentrations of glucose at 5 mM, 10 mM, and 25 mM for 2 days. Then, the cellular 2-deoxyglucose uptake and cAMP concentration of cultured human corneal endothelial cells were measured. The results indicated that the activity of cellular glucose uptake of nmole/min/mg protein was decreased gradually from 0.18 (5 mM), 0.10 (10 mM), 0.07 (20 mM) to 0.06 (25 mM) after 2 days incubation with a high concentration of glucose. The glucose uptake in insulin-treated human corneal endothelial cells also exhibited a similar declining effect in high glucose media from 0.30 (5 mM), 0.11 (10 mM), 0.08 (20 mM) to 0.05 (25 mM). The cAMP concentration in human corneal endothelial cells was measured in the presence of high glucose media. It was indicated that the cAMP concentrations of pmole/well in both insulin-treated and non-insulin treated cells were also decreased after increasing the glucose concentration in the media from 73 (5 mM) to 20 (25 mM) and 101 (5 mM) respectively. The cAMP concentration in insulin-treated cells was less than in non-insulin treated cells. This decreasing effect was significantly reversed by the addition of 1 mM dibutyryl-cAMP to the cells for 1 hour in both groups. These results suggest that the diabetic state may decrease the 2-deoxyglucose uptake in human corneal endothelial cells via cAMP-dependent pathway.

Effects of antiglaucoma drugs and corticosteroids on the cellular glucose uptake in cultured porcine corneal endothelial cells

In this study, various commercially used antiglaucoma drugs and corticosteroids were investigated in their effects on porcine corneal endothelial cells especially in cellular glucose uptake. Cellular glucose uptake directly affects the pumping efficiency in corneal endothelial cells. Following the cells' treatment with various antiglaucoma eyedrops for 100 min, the 3H-2-deoxyglucose uptake in cultured porcine corneal endothelial cells was affected by betaxolol from 3.1% (1.6 mM), 181% (0.16 mM) to 158% (0.016 mM), by timolol from 93% (0.79 mM), 227% (0.079 mM) to 151% (0.0079 mM), by carteolol from 141% (3.4 mM), 180% (0.34 mM) to 97% (0.034 mM), by levobunolol from 80% (1.5 mM), 98% (0.15 mM) to 90% (0.015 mM), by dipivefrin from 116% (0.2 mM), 176% (0.02 mM) to 108% (0.002 mM) and by pilocarpine from 115% (9.6 mM), 210% (0.96 mM) to 210% (0.096 mM) when the cells were compared with a control medium. In the presence of various corticosteroids, the glucose uptake in corneal endothelial cells was affected by fluorometholone from 160% (0.26 mM), 139% (0.026 mM) to 107% (0.0026 mM), by dexamethasone from 85% (0.25 mM), 117% (0.025 mM) to 109% (0.0025 mM) and by betamethasone from 95% (0.25 mM), 96% (0.025 mM) to 99% (0.0025 mM). These results show that the commercial eyedrops of antiglaucoma drugs and corticosteroids will not decrease the cellular glucose uptake in cultured porcine corneal endothelial cells except when incubated with high concentrations of betaxolol, levobunolol and dexamethasone.

Telomerase activity: a potential marker of bladder transitional cell carcinoma in bladder washes

The enzyme telomerase maintains a constant telomere length in immortalized cells, allowing unlimited cell proliferation. Almost all cancer cells express telomerase activity. However, little data is available regarding the role of telomerase activity in the detection of bladder cancer with a bladder wash specimen. We detected telomerase activity in a bladder wash specimen of bladder cancer and normal tissues, and compared them with final pathologic diagnosis. Twenty-three patients with transitional cell carcinoma (TCC) of the bladder were enrolled in our study. A bladder wash specimen was obtained before transurethral resection of the bladder (TURB) and normal and cancer tissues from the same patients during TURB. Telomerase activity was analyzed in each specimen a using telomeric repeat amplification protocol (TRAP) assay based on polymerase chain reaction (PCR) technique. Cytologic diagnosis was performed using Papanicolaou's stain with cytocentrifuged cytology preparation. We observed telomerase activity in 95.7% (22/23) of bath cancer tissues and bladder wash specimens; only one case did not express telomerase activity. Telomerase activity was undetected in all normal tissues except one, which was obtained from a patient with carcinoma in situ. A total of 69.6% (16/23) of wash specimens were positive in cytopathologic diagnosis. The accuracy of cytopathologic diagnosis in pathologic grade 2 or 3 was relatively high (83.3%, 15/18). However, in five cases of grade 1 TCC only 20% (1/5) of cytologic diagnosis was positive whereas the telomerase activity of wash specimens was detected in 80% (4/5). Our data demonstrates that not only the majority of human bladder cancer tissues, but also the bladder wash specimens obtained from patients with TCC, expressed telomerase activity. It indicates that telomerase activity may be a reliable marker in detecting bladder cancer especially in cases with a low grade that bladder wash cytology can miss.