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.

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.

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.

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.