Maxizymes, novel allosterically controllable ribozymes, can be designed to cleave various substrates

We demonstrated previously that an allosterically controllable novel ribozyme, designated the maxizyme, is a powerful tool for disruption of an abnormal chimeric RNA target [BCR-ABL (b2a2) mRNA], and we proposed that it might provide the basis for future gene therapy for the treatment of chronic myelogenous leukemia (Kuwabara et al. Mol. Cell 1998, 2, 617-627). The maxizyme has sensor arms that can recognize a specific sequence and, in the presence exclusively of such a specific sequence, it can form a cavity for capture of catalytically indispensable Mg2+ ions. Cleavage of the target RNA then occurs at a site distant from the specific sequence. Clearly, the specific sequences recognized by sensor arms should not be limited to those of the above mentioned abnormal chimeric target. Thus, to demonstrate the general applicability of maxizyme technology, we constructed maxizymes targeted to other mRNAs, such as PML-RAR alpha mRNA, sDLST mRNA, and BCR-ABL (b1a2) mRNA, that are not cleaved with high specificity by the wild-type hammerhead ribozyme. Specific and efficient cleavage in vitro of these mRNAs by the custom-designed maxizymes demonstrated clearly that maxizyme technology is not limited to a specific case but may have broad general applicability in molecular biology and, also, in a clinical setting.

Constitutive expression of the cyclooxygenase-2 gene in T-cell lines infected with human T cell leukemia virus type I

Cyclooxygenase-2 (COX-2), an inducible enzyme that catalyzes the formation of prostaglandins and other eicosanoids from arachidonic acid, is constitutively expressed in several human carcinomas. COX-2 expression, however, has not been extensively studied in leukemia. Human T cell leukemia virus type I (HTLV-I) is the etiologic agent of adult T cell leukemia, an aggressive form of human T cell malignancy. We studied COX-2 mRNA expression in various human T-cell lines. Northern blot analysis revealed that COX-2 mRNA steady-state levels were high in 4 of 7 T-cell lines infected with HTLV-I. COX-2 mRNA, however, was not expressed in any of 3 HTLV-I-negative T-cell lines. We also confirmed COX-2 expression in 6 of 7 HTLV-I-positive T-cell lines by reverse transcription-PCR. HTLV-I Tax is known to increase the expression of cellular genes and thus we assayed Tax for its ability to increase transcription from the COX-2 promoter. Although Tax increased transcription of the COX-2 promoter in a T-cell line, Tax expression did not induce COX-2 mRNA expression, indicating that Tax alone is not sufficient for significant accumulation of COX-2 mRNA, which probably requires an additional viral protein. To evaluate the potential role of COX-2 in T cells, the HTLV-I-infected T-cell lines were treated with NS398, a selective COX-2 inhibitor. NS398 treatment inhibited proliferation and induced apoptosis of HTLV-I-infected T-cell lines and downregulated Bcl-2 and Bcl-x(L) mRNA expression, followed by chromosomal DNA fragmentation. Our data suggest that COX-2 is expressed selectively in T-cell lines infected with HTLV-I and that this gene may play a role in cell survival.

Mice lacking Ca(v)2.3 (alpha1E) calcium channel exhibit hyperglycemia

To investigate the functional role of Ca(v)2.3 channel in glucose homeostasis, we performed in vivo glucose tolerance and insulin tolerance tests together with stress-induced glucose release tests using mice deficient in Ca(v)2.3 channel (Ca(v)2.3-/-). The Ca(v)2.3-/- mice were significantly heavier than wild-type mice. In glucose tolerance and insulin tolerance tests, Ca(v)2.3-/- mice showed a significantly higher blood glucose level compared to wild-type mice. However, stress-induced blood glucose changes in Ca(v)2.3-/- mice were similar to those in wild-type mice. These results suggest that Ca(v)2.3 channel plays a role in glucose homeostasis by reducing insulin sensitivity and that Ca(v)2.3-/- mice exhibit symptoms resembling non-insulin-dependent diabetes mellitus.

Prostacyclin-dependent apoptosis mediated by PPAR delta

Prostacyclin (PGI(2)) plays important roles in hemostasis both as a vasodilator and an endogenous inhibitor of platelet aggregation. PGI(2) functions in these roles through a specific IP receptor, a G protein-coupled receptor linked to G(s) and increases in cAMP. Here, we report that intracellular prostacyclin formed by expressing prostacyclin synthase in human embryonic kidney 293 cells promotes apoptosis by activating endogenous peroxisome proliferator-activated receptor delta (PPAR delta). In contrast, treatment of cells with extracellular prostacyclin or dibutyryl cAMP actually reduced apoptosis. On the contrary, treatment of the cells with RpcAMP (adenosine 3',5'-cyclic monophosphothioate, Rp-isomer), an antagonist of cAMP, enhanced prostacyclin-mediated apoptosis. The expression of an L431A/G434A mutant of PPAR delta completely blocked prostacyclin-mediated PPAR delta activation and apoptosis. These observations indicate that prostacyclin can act through endogenous PPAR delta as a second signaling pathway that controls cell fate.

Feline immunodeficiency virus lacks sensitivity to the antiviral activity of feline IFN-gamma

The antiviral activity of recombinant feline interferon-gamma (rFeIFN-gamma) against feline immunodeficiency virus (FIV) was investigated. A persistently FIV(Bang)-infected feline T cell line (FeT-J/Bang) was treated with either rFeIFN-omega, rFeIFN-gamma, or recombinant human IFN-alpha2 (rHuIFN-alpha2), and the culture fluids were tested for antiviral activity by reverse transcriptase (RT) assay. FeT-J/Bang cell cultures treated with rFeIFN-omega showed dose-dependent inhibition of RT activity. In contrast, rFeIFN-gamma treatment had no antiviral effect on FIV replication but instead caused a statistically significant enhancement on day 9 of culture. Antiviral activity of rFeIFN-gamma was also tested on feline peripheral blood mononuclear cells (PBMC). PBMC cultures were inoculated with FIV(Bang) and simultaneously treated with either rFeIFN-omega, rFeIFN-gamma, or rHuIFN-alpha2. FeIFN-gamma had no effect on FIV replication, unlike the rFeIFN-omega and rHuIFN-alpha2, which had strong anti-FIV effects. In another study, rFeIFN-gamma treatment was initiated 3 days before FIV(Bang) infection, the day of FIV(Bang) infection, or 3 days post-FIV(Bang) infection and then tested for antiviral activity. The time of initiating rFeIFN-gamma treatment had no effect on the antiviral activity. Hence, these results suggest that unlike rHuIFN-alpha2 and rFeIFN-omega, rFeIFN-gamma has no inhibitory effect on FIV replication in PBMC but causes a slight enhancement in a feline T cell line.

Characterization of acute somatosensory pain transmission in P/Q-type Ca(2+) channel mutant mice, leaner

To study the role of the Ca(v)2.1/alpha(1A) (P/Q-type) Ca(2+) channel in somatosensory pain processing, behavioral and electrophysiological studies were conducted using the leaner (tg(la)/tg(la)) mouse. Behavioral analyses in tg(la)/tg(la) revealed reduced responses to mechanical stimuli, and enhanced responses to heat stimuli. Electrophysiological analyses showed that tg(la)/tg(la) had a significantly reduced ability to evoke dorsal root potentials, suggesting a functional deficit in the spinal dorsal horn local circuitry responsible for presynaptic inhibition of primary sensory fibers. These results suggest the critical importance of the P/Q-type channel in modulation of acute somatosensory pain transmission in spinal cord.

Analysis of Ca(2+) currents in spermatocytes from mice lacking Ca(v)2.3 (alpha(1E)) Ca(2+) channel

In mammalian male germ-line cells, low-voltage-activated (LVA) Ca(2+) current has been identified and its electrophysiological properties have been studied. To investigate whether alpha(1)2.3 (alpha(1E)) subunit of the voltage-dependent Ca(2+) channel codes for the LVA current, whole-cell patch clamp and following reverse transcription-polymerase chain reaction (RT-PCR) experiments were performed in pachytene spermatocytes from Ca(v)2.3+/+ and Ca(v)2.3-/- mice. Whole-cell current in acutely dissociated pachytene spermatocytes from Ca(v)2.3+/+ and Ca(v)2.3-/- mice displayed a typical profile of LVA Ca(2+) currents and kinetics with no significant differences. Single-cell RT-PCR revealed the expression of Cacna1g in the pachytene spermatocytes from Ca(v)2.3+/+ and Ca(v)2.3-/- mice in which LVA Ca(2+) currents were actually recorded. These results suggest that the Ca(v)2.3 channel makes no detectable contribution to the LVA Ca(2+) current in the pachytene spermatocyte. Instead, Ca(v)3 family such as Ca(v)3.1 may be the likely candidates responsible for the LVA currents in pachytene spermatocytes.

Immunoelectron-microscopic demonstration of histamine depletion in the gastric enterochromaffin-like cells of rats treated with alpha-fluoromethylhistidine

We conducted an immunoelectron-microscopic study for histamine (HA) in the enterochromaffin-like (ECL) cells of normal rats and rats given alpha-fluoromethylhistidine (alpha-FMH, 3 mg/kg per hour) via osmotic minipumps over a period of 24 h. The indirect immunoperoxidase procedure utilized a mouse monoclonal antibody (mAb), AHA-2, which is produced against glutaraldehyde-conjugated HA. alpha-FMH is a potent and irreversible inhibitor of the HA-forming enzyme histidine decarboxylase and is known to reduce tissue HA concentrations in several tissues. The present study clearly demonstrated that HA immunoreactivity, which was found to a high degree in the cores of the granules and secretory vesicles and in the cytoplasm of ECL cells of control rats, was completely abolished from the corresponding compartments in the cells of alpha-FMH-treated rats. Furthermore, treatment with alpha-FMH drastically lowered the number of secretory vesicles and was associated with larger cores in the granules of the ECL cells. These results seem to support the idea of a HA-pathway mechanism, emphasizing that the granules in normal ECL cells take up HA from the cytosol during its transport from the Golgi zone to the more peripheral portion of the cell and condense it in their cores, thus forming mature secretory vesicles. However, the present study showed that not only the secretory vesicles but also almost all the granules seen in ECL cells were already loaded with HA in their cores, suggesting that the newborn granules very rapidly take up HA from the cytosol. Also suggested was the fact that HA depletion impairs the maturation of the granules into secretory vesicles.

Calcium binding of enamel proteins and their derivatives with emphasis on the calcium-binding domain of porcine sheathlin

Dental enamel is believed to form by the transfer of ions from solution, primarily calcium, phosphate, hydroxyl and carbonate, to the surface of solid-state mineral. Such precipitation phenomena can be controlled by regulating the degree of saturation of the solution with respect to the potential solid phases that can form. The concentration of free calcium is the factor that most affects the degree of saturation for calcium hydroxyapatite, and its buffering by calcium-binding proteins has been proposed as the mechanism that determines the enamel mineral structure. In this study, Stains-all staining was used to identify and isolate calcium-binding proteins from the enamel matrix, and determine their structures and association constants for calcium. Proteolytic cleavage fragments derived from the C-terminus of sheathlin, having apparent molecular weights of 13, 15, 27 and 29 kDa, were characterized by amino-terminal protein sequencing, amino acid analysis, and sugar, phosphate and sulphate determinations. Sheathlin C-terminal cleavage products were shown to have no N-linked glycosylations or phosphorylated amino acids, but Pro(350) was hydroxylated, and there was one sulphated O-linked glycosylation at Thr(386), containing galactose and N-acetylgalactosamine. The calcium-binding association constants for enamel proteins ranged from a high of 1.2 x 10(4) M(-1) to a low of 4.4x10(1) M(-1). The relative strengths of binding in order of decreasing affinity were: 13 and 15 kDa calcium-binding domain of sheathlin >27 and 29 kDa calcium-binding proteins >32 kDa enamelin >89 kDa enamelin >6.5 kDa, 25 kDa, 23 kDa, 20 kDa, 13 kDa, 5.3 kDa amelogenins. It is concluded that if enamel proteins have similar calcium-binding properties in vivo as have been measured in vitro, they would tend to buffer the free calcium ion concentration in enamel fluid.

[Usefulness of near-infrared spectroscopy for identification of epileptic foci in two localization-related epilepsy patients]

We monitored cerebral blood volume (CBV) using near-infrared spectroscopy (NIRS) of two patients with symptomatic localization-related epilepsy who had no epileptic discharges in ictal scalp EEG. Case 1 was a 9-month-old boy who was suspected to have frontal lobe epilepsy. Although epileptic discharges were not identified on his ictal EEG due to motion artifacts, NIRS demonstrated an increase of CBV of the left brain during the seizure. Ictal single photon emission CT (SPECT) was dominant at the left side. Case 2 was a 3-year-old girl who was suspected to have temporal lobe epilepsy. Ictal EEG tracings, theta waves revealed prominent but did not enable identification of the focus. She had cortical dysplasia in the right cerebral hemisphere. NIRS monitoring demonstrated an increase in CBV in the right frontal region, which began 10 minutes before the seizure onset and lasted for 3 hours. Thus NIRS is a sensitive and non-invasive procedure for monitoring CBV changes during the seizure, and is useful in identification of the epileptic focus.

[Assessment of myocardial fatty acid metabolism in patients with angina pectoris and diabetes mellitus using 123I-BMIPP myocardial scintigraphy]

PURPOSE

We studied the effect of myocardial ischemia and diabetes mellitus (DM) on the myocardial fatty acid metabolism using 123I-BMIPP myocardial scintigraphy.

METHODS

We performed 123I-BMIPP myocardial scintigraphy in 50 patients with myocardial ischemia and without DM (AP), in 30 patients with myocardial ischemia and DM (AP + DM), 12 patients with DM and without myocardial ischemia (DM), and in 10 normal subjects (N). Myocardial uptake rate of 123I-BMIPP was obtained using the time activity curve. Myocardial washout rate of 123I-BMIPP was calculated using the polar images of early and delayed SPECT images.

RESULTS

Myocardial uptake rate of 123I-BMIPP (%) were AP: 4.9 +/- 0.6, AP + DM: 5.5 +/- 0.5, DM 5.7 +/- 0.5 and N: 5.0 +/- 0.4. 123I-BMIPP myocardial uptake rate was increased in AP + DM and DM. 123I-BMIPP myocardial washout rate (%) were AP: 30.2 +/- 4.3, AP + DM: 24.5 +/- 3.9, DM: 16.1 +/- 2.8 and N: 19.4 +/- 3.2. 123I-BMIPP myocardial washout rate was increased in AP and AP + DM. 123I-BMIPP myocardial washout rate was increased particularly in patients with multi-vessels disease. 123I-BMIPP myocardial washout rate was decreased in DM.

CONCLUSION

The present study suggested that diabetes mellitus increased myocardial fatty acid uptake and decreased myocardial fatty acid washout, and that myocardial ischemia increased myocardial fatty acid washout.

[Function of calcium channels--newly identified from the analysis of knockout mice]

In the last 14 years, many types of calcium channels have been cloned and extensively studied using electrophysiological and pharmacological means combined with molecular biological techniques. These structure -function analyses have clarified the biophysical nature and modulation of each type of calcium channels leading to the establishment of these molecular bases. Recently, a wave of gene targeting technology has swept over the researchers in the ion channel field and several types of calcium channel knockout mice have started to be generated. Analyses of these mice have identified several novel physiological functions of the calcium channel. This report will introduce some of these studies.

Longer longitudinal atrial dimension in patients with idiopathic paroxysmal atrial fibrillation: A possible cause of atrial fibrillation

BACKGROUND

The ostium of the superior pulmonary veins or superior vena cava has been reported to be an important source of the ectopic beats that initiate paroxysmal atrial fibrillation (PAF). The structural details of the atria in patients with idiopathic PAF, however, remain unknown.

METHODS

We studied 113 patients (92 men and 21 women) with idiopathic PAF and 128 normal control subjects (100 men and 28 women). None of the subjects in either group were found to have any evidence of structural cardiac disease. The echocardiographic measurements were performed in the apical 4-chamber view during end-systole of sinus rhythm.

RESULTS

The longitudinal dimension of the left and right atria was longer in patients with PAF who were not administered any drugs (non-drug-taking patients) than in the control subjects (P <.001 and P <.01, respectively). However, there were no significant differences in the transverse dimension of either atrium between such patients and control subjects. The longitudinal and transverse dimensions and volume determinations of atria were greater in the patients with idiopathic PAF who were administered class 1 antiarrhythmic drugs than in non-drug-taking patients (P <.05 to.001). In non-drug-taking patients, prolongation of the atrial longitudinal dimension did not depend on either age, the total frequency of PAF, or the interval from the first episode of PAF. The longitudinal dimension of the left and right atria was longer even in the patients with a short history of PAF (<1 month) as compared with control subjects (P <.001 and.05, respectively).

CONCLUSIONS

These observations suggest that there is prolongation of the longitudinal dimension in patients with idiopathic PAF independent of PAF frequency and age (and that PAF is probably a consequence of the prolongation).

Effects of fibronectin bonding on healing of high porosity expanded polytetrafluoroethylene grafts in pigs

BACKGROUND

We developed a new fibronectin bonding to expanded polytetrafluoroethylene (ePTFE) and previously reported that, in a dog carotid implant model, fibronectin bonding improves graft healing in high porosity ePTFE grafts. The purpose of this study was to further investigate the effect of the fibronectin bonding on graft healing in a pig carotid implant model.

METHODS

Fifteen pigs received a high porosity ePTFE graft treated with the fibronectin bonding (fibronectin-bonded graft) on one side and an untreated graft (non-bonded graft) on the contralateral side. The grafts were explanted at intervals of 3 and 6 weeks and subjected to histological studies.

RESULTS

At 3 weeks, the neointima of fibronectin-bonded grafts was better organized than that of non-bonded grafts. At 6 weeks, the morphologic features of the neointima were the same in fibronectin-bonded and non-bonded grafts. The neointima was completely organized.

CONCLUSIONS

Together with the previous results with the dog model, fibronectin bonding could be expected to improve healing of the high porosity ePTFE grafts in humans.

Coupling between cyclooxygenase, terminal prostanoid synthase, and phospholipase A2

We have recently shown that two distinct prostaglandin (PG) E(2) synthases show preferential functional coupling with upstream cyclooxygenase (COX)-1 and COX-2 in PGE(2) biosynthesis. To investigate whether other lineage-specific PG synthases also show preferential coupling with either COX isozyme, we introduced these enzymes alone or in combination into 293 cells to reconstitute their functional interrelationship. As did the membrane-bound PGE(2) synthase, the perinuclear enzymes thromboxane synthase and PGI(2) synthase generated their respective products via COX-2 in preference to COX-1 in both the -induced immediate and interleukin-1-induced delayed responses. Hematopoietic PGD(2) synthase preferentially used COX-1 and COX-2 in the -induced immediate and interleukin-1-induced delayed PGD(2)-biosynthetic responses, respectively. This enzyme underwent stimulus-dependent translocation from the cytosol to perinuclear compartments, where COX-1 or COX-2 exists. COX selectivity of these lineage-specific PG synthases was also significantly affected by the concentrations of arachidonate, which was added exogenously to the cells or supplied endogenously by the action of cytosolic or secretory phospholipase A(2). Collectively, the efficiency of coupling between COXs and specific PG synthases may be crucially influenced by their spatial and temporal compartmentalization and by the amount of arachidonate supplied by PLA(2)s at a moment when PG production takes place.

Glucocorticoid-regulated expression of exogenous human growth hormone gene in rats

The aim of this study was to control in vitro and in vivo expression of the growth hormone (GH) gene using a glucocorticoid-sensitive promoter, the mouse mammary tumor virus long terminal repeat (MMTV LTR). We inserted the cDNA encoding the 20-kDa form of human GH (20K-GH) downstream of the MMTV LTR of plasmid pMSG, and used lipofection to transfer it to 3Y1 cells together with plasmid pMX, which contains a puromycin-resistant element. The secretion of GH from the selected transformants was dose-dependently augmented by the application of hydrocortisone, corticosterone, or dexamethasone, among which dexamethasone was the most potent. Analysis of the time course showed that 20K-GH secretion began to increase within 2 hours after the addition of glucocorticoid and reached a maximal level of about threefold over the unstimulated control at 3 hours; secretion then gradually declined and returned to near basal levels at 19 hours. Repeated glucocorticoid application led to repeated increases in GH secretion. When GH-producing cells were microcapsulated and transplanted into the abdominal cavities of rats, 20K-GH was detected in the plasma under control conditions and increased about 3.3-fold after administration of dexamethasone. We suggest that GH expression driven by the MMTV LTR promoter may be under the control of an endogenous glucocorticoid in vivo.

[Clinical significance of the Streptococcus milleri group in peritonsillar abscesses]

Few researchers have microbiologically studied peritonsillar abscesses in detail, and their results have been conflicting. Although Streptococcus pyogenes (Group A beta-streptococcus) is commonly considered an important pathogen in this infection, recent studies have demonstrated the recovery of many other streptococci mainly consisting of alpha-streptococci. Few studies have identified these streptococci at the species level, however. We studied details of bacteriology in 31 cases of peritonsillar abscess treated between 1991 and 2000. The Streptococcus milleri group was most frequently isolated (25.8%), followed by Eikenella corrodens (9.7%), Staphylococcus aureus (6.5%), and S. pyogenes (3.2%). The S. milleri group, consisting of 3 species of Streptococcus constellatus, S. intermedius, and S. anginosus, forms part of the normal flora most commonly found in the mouth, throat, gastrointestinal tract, and genital tract. These species have become known as an important pathogen in abscess disease but little attention has been paid to their role in peritonsillar abscesses. To adequately culture the S. milleri group, incubation in air containing carbon dioxide or in an anaerobic condition is required, and then the differentiation of the 3 species requires the biochemical reactivity tests. Since hemolytic patterns of the S. milleri group vary, we studied the population of alpha-, beta-, and gamma-hemolytic strains among 36 strains of this group. We found 32 (88.8%) to be alpha-hemolytic. Although not all alpha-hemolytic strains belong to the S. milleri group, a considerable number of this group could be missed among alpha-streptococci isolated from the peritonsillar abscess. As antibiotics began being used widely, normal flora such as the S. milleri group may have become an important pathogen in peritonsillar abscesses due to an imbalance between organisms and host defense.

Effect of age on rat aortic responses to acetylcholine and nitric oxide donor (NOC-18)

The purpose of the present study was to examine the effects of age on vascular responses to acetylcholine (ACh) and NO-releasing compound (NOC-18). The studies were performed in young (4 months old, n = 8) and old (22 months old, n = 6) male rats. Responses to ACh and NOC-18 were examined in vitro by using isolated abdominal aortic rings. The maximum relaxation response to ACh, an endothelium-dependent vasodilation, was lower in aortas from old rats. Sensitivity (mean effective concentration; EC50) of ACh in old rats was significantly less than in young rats. There were no differences in maximum NOC-18-induced relaxation, an endothelium-independent vasodilation, in aortas from young and old rats. On the other hand, the concentration-response curve for NOC-18 was shifted to the right and the sensitivity (EC50 to NOC-18) was lower in old rats. These results indicated that both endothelium-dependent vasodilation induced by ACh and endothelium-independent vasodilation induced by NOC-18 are impaired in aorta from old rats.

Multiple G-protein-coupled receptors mediate presynaptic inhibition at single excitatory synapses in the rat visual cortex

Modulation of excitatory synaptic transmission by agonists for several neurotransmitter receptors was investigated at intrinsic cortical synapses derived from single presynaptic neurons. Excitatory postsynaptic currents (EPSCs) were recorded from layer 5 pyramidal neurons in the rat visual cortex in response to minimal stimulation within the same layer. 5-hydroxytryptamine, adenosine, baclofen, carbachol and DCG-IV all suppressed EPSCs with an increase in paired-pulse ratio. These agonists reduced the frequency of miniature EPSCs without significantly affecting their amplitude distribution. These results suggest that glutamatergic excitatory transmission in the neocortex is under the control of presynaptic inhibition mediated by multiple neuromodulator receptors co-expressed in single presynaptic terminals.

Assessment of ampulla (Takotsubo) cardiomyopathy with coronary angiography, two-dimensional echocardiography and 99mTc-tetrofosmin myocardial single photon emission computed tomography

We studied the causative mechanism of ampulla (Takotsubo) cardiomyopathy.

METHODS

We examined 7 patients with ampulla cardiomyopathy by means of coronary angiography, two-dimensional echocardiography and 99Tc-tetrofosmin myocardial SPECT at the time of emergency admission (acute phase), at 3 to 5 days after the attack (subacute phase) and at 1 month after the attack (chronic phase). The left ventricle was divided into 9 regions on two-dimensional echocardiograms and 99mTc-tetrofosmin myocardial SPECT images, then the degree of abnormalities in each region was scored in four grades from normal (0) to severely abnormal (3). We injected nicorandil into the coronary arteries and determined the elevation in the ST segment before and after administration.

RESULTS

Coronary angiography did not show stenotic lesions in any patient. The acute, subacute and chronic phase myocardial perfusion scores on 99mTc-tetrofosmin myocardial SPECT were 11.2 +/- 3.4, 2.7 +/- 2.3 and 0.4 +/- 0.5, respectively, and wall motion scores on echocardiograms were 13.0 +/- 3.6, 4.4 +/- 2.2 and 0.6 +/- 0.6, respectively, indicating improvement in all scores during the subacute phase (p < 0.01). The elevation in the ST segment (mm) on the electrocardiogram was improved from 8.3 +/- 2.7 to 4.9 +/- 1.9 after the administration of nicorandil (p < 0.05).

CONCLUSION

These findings indicated that coronary microvascular spasm is one causative mechanism of ampulla cardiomyopathy.

Dual-subtype FIV vaccine protects cats against in vivo swarms of both homologous and heterologous subtype FIV isolates

OBJECTIVE

To evaluate the immunogenicity and efficacy of an inactivated dual-subtype feline immunodeficiency virus (FIV) vaccine.

DESIGN

Specific-pathogen-free cats were immunized with dual-subtype (subtype A FIV(Pet) and subtype D FIV(Shi)) vaccine and challenged with either in vivo- or in vitro-derived FIV inocula.

METHODS

Dual-subtype vaccinated, single-subtype vaccinated, and placebo-immunized cats were challenged within vivo-derived heterologous subtype B FIV(Bang) [10--100 50% cat infectious doses (CID(50))], in vivo-derived homologous FIV(Shi)(50 CID(50)), and in vitro- and in vivo-derived homologous FIV(Pet)(20--50 CID(50)). Dual-subtype vaccine immunogenicity and efficacy were evaluated and compared to single-subtype strain vaccines. FIV infection was determined using virus isolation and proviral PCR of peripheral blood mononuclear cells and lymphoid tissues.

RESULTS

Four out of five dual-subtype vaccinated cats were protected against low-dose FIV(Bang) (10 CID(50)) and subsequently against in vivo-derived FIV(Pet) (50 CID(50)) challenge, whereas all placebo-immunized cats became infected. Furthermore, dual-subtype vaccine protected two out of five cats against high-dose FIV(Bang) challenge (100 CID(50)) which infected seven out of eight single-subtype vaccinated cats. All dual-subtype vaccinated cats were protected against in vivo-derived FIV(Pet), but only one out of five single-subtype vaccinated cats were protected against in vivo-derived FIV(Pet). Dual-subtype vaccination induced broad-spectrum virus-neutralizing antibodies and FIV-specific interferon-gamma responses along with elevated FIV-specific perforin mRNA levels, suggesting an increase in cytotoxic cell activities.

CONCLUSION

Dual-subtype vaccinated cats developed broad-spectrum humoral and cellular immunity which protected cats against in vivo-derived inocula of homologous and heterologous FIV subtypes. Thus, multi-subtype antigen vaccines may be an effective strategy against AIDS viruses.

Immobilized fluorescent cyclodextrin on a cellulose membrane as a chemosensor for molecule detection

Dansylglycine-modified cyclodextrin (DnsC4-beta-CD) was prepared as a fluorescent host that is capable of being immobilized on a cellulose membrane (DnsC4-beta-CD membrane). DnsC4-beta-CD immobilized on the cellulose membrane decreased its fluorescence intensity with increasing concentration of guest molecules, indicating that the host changes the location of the dansyl group from inside to outside the cyclodextrin cavity upon guest accommodation, which is similar to DnsC4-beta-CD in solution; thereby, the DnsC4-beta-CD membrane is useful as a novel chemosensor for detecting molecules. This result demonstrates that the cellulose membrane is useful as a practical supporting material for various chromophore-modified cyclodextrins.

[Assessment of myocardial damage and metabolic disorder in the left ventricle in patients with mitral stenosis using 201Tl and 123I-BMIPP myocardial SPECT]

This study was designed to evaluate the myocardial damage and metabolic disorder of the left ventricle in patients with mitral stenosis. We studied 15 patients with mitral stenosis. Their grade of chronic heart failure using New York Heart Association classification were class I: 5 patients, class II: 5, class III: 3, class IV: 2, respectively. The severely stenotic group (valve area < 1.5 cm2) included 6 patients, mildly stenotic group (1.5 cm2 < or = valve area < 2.5 cm2) included 9. A 111 MBq of 123I-BMIPP was intravenously injected at rest, SPECT images were obtained at 15 min and 3 hours after injection. A 111 MBq of 201Tl was intravenously injected at rest, and SPECT images were obtained at 15 min after injection. Washout rate (WR) of 123I-BMIPP from the whole left ventricle was obtained using polar maps. The concentration of norepinephrine (NE: pg/ml) in the blood at rest was measured. The mean values of pulmonary artery pressure was measured in ten patients using Swan-Ganz catheter. 123I-BMIPP myocardial SPECT and measurement of NE were reexamined in 5 patients after mitral valvuloplasty. NE values were 476 +/- 72 and 793 +/- 286 in classes I + II and III + IV, respectively. NE values was increased in the severe heart failure group (p < 0.05). NE values were 480 +/- 69 and 743 +/- 295 in the mildly and severely stenotic groups, respectively. NE value was increased in severely stenotic group (p < 0.05). Twelve patients showed normal uptake on both 201Tl and 123I-BMIPP myocardial SPECT. Three patients showed slightly reduced uptake on both 201Tl and 123I-BMIPP myocardial SPECT. WR was 27.2 +/- 4.8% and 44.3 +/- 6.7% in class I + II and class III + IV, respectively. WR was increased in severe heart failure group (p < 0.05). WR was 27.8 +/- 6.0% and 41.3 +/- 9.4% in the mildly and severely stenotic group, respectively. WR was increased in the severely stenotic group (p < 0.05). NE was correlated with WR (p < 0.001). In patients with mitral valvuloplasty, WR was 44.3 +/- 6.7% and 31.4 +/- 4.7% before and after mitral valvuloplasty, respectively. NE values were 857 +/- 266 and 574 +/- 165, respectively. Both WR and NE were decreased after mitral valvuloplasty (p < 0.01). In patients with mitral stenosis, WR was increased in the severe heart failure group and severely stenotic group without apparent myocardial damage. Myocardial metabolism in the left ventricle might be influenced by right heart failure through, for example, NE and neurohormonal factors.

Overlapping CRE and E-box promoter elements can independently regulate COX-2 gene transcription in macrophages

Macrophage cyclooxygenase-2 (COX-2) transcription is mediated through the collaboration of different promoter elements. Here, the role of an overlapping cyclic AMP responsive element (CRE)/E-box was investigated. Nuclear proteins bound both the CRE and E-box, which synergized with other promoter elements to induce COX-2 transcription. Endotoxin induced binding of nuclear proteins to the CRE and E-box and each element independently induced higher COX-2 transcription levels than the overlapping CRE/E-box. Transcription factors associated with the CRE binding complex included c-Jun and CRE binding protein and with the E-box binding complex USF-1; their overexpression significantly induced COX-2 transcription. Therefore, both CRE and E-box promoter elements regulate COX-2 transcription in macrophages.

Cytoplasmic and nuclear polyglutamine aggregates in SCA6 Purkinje cells

Aggregations of the alpha1A-calcium channel protein have been previously demonstrated in spinocerebellar ataxia type 6 (SCA6). Here the authors show that small aggregates, labeled by a monoclonal antibody 1C2 that preferentially detects expanded polyglutamine larger than that in SCA6 mutation, are present mainly in the cytoplasm but also in the nucleus of Purkinje cells. Although the length of expansion is small in SCA6, the current finding might indicate that SCA6 conforms to the pathogenic mechanism(s) in other polyglutamine diseases.

Induction of cyclooxygenase-2 by Epstein-Barr virus latent membrane protein 1 is involved in vascular endothelial growth factor production in nasopharyngeal carcinoma cells

Cyclooxygenase-2 (COX-2) is an inducible form of COX and is overexpressed in diverse tumors, raising the possibility of a role for COX-2 in carcinogenesis. In addition, COX-2 contributes to angiogenesis. The Epstein-Barr virus (EBV) oncoprotein, latent membrane protein 1 (LMP1), is detected in at least 70% of nasopharyngeal carcinoma (NPC) and all EBV-infected preinvasive nasopharyngeal lesions. We found that in specimens of LMP1-positive NPC, COX-2 is frequently expressed, whereas LMP1-negative NPC rarely express the enzyme. We next found that expression of LMP1 in EBV-negative nasopharyngeal epithelial cells induced COX-2 expression. Coexpression of IkappaBalpha(S32A/S36A), which is not phosphorylated and prevents NF-kappaB activation, with LMP1 showed that NF-kappaB is essential for induction of COX-2 by LMP1. We also demonstrate that NF-kappaB is involved in LMP1-induced cox-2 promoter activity with the use of reporter assays. Two major regions of LMP1, designated CTAR1 and CTAR2, are signal-transducing domains of LMP1. Constructs expressing either CTAR1 or CTAR2 induce COX-2 but to a lesser extent than wild-type LMP1, consistent with the ability of both regions to activate NF-kappaB. Furthermore, we demonstrate that LMP1-induced COX-2 is functional because LMP1 increased production of prostaglandin E(2) in a COX-2-dependent manner. Finally, we demonstrate that LMP1 increased production of vascular endothelial growth factor (VEGF). Treatment of LMP1-expressing cells with the COX-2-specific inhibitor (NS-398) dramatically decreased production of VEGF, suggesting that LMP1-induced VEGF production is mediated, at least in part, by COX-2. These results suggest that COX-2 induction by LMP1 may play a role in angiogenesis in NPC.

Pars plana vitrectomy for cystoid macular edema secondary to sarcoid uveitis

OBJECTIVE

To examine the results of pars plana vitrectomy for cystoid macular edema secondary to sarcoid uveitis resistant to medical treatment.

DESIGN

Retrospective, interventional, noncomparative case series.

SUBJECTS

Fourteen consecutive subjects (18 eyes) with cystoid macular edema associated with sarcoid uveitis resistant to medical treatment.

INTERVENTION

All eyes underwent pars plana vitrectomy. Nine eyes also underwent peeling of the epiretinal membrane or removal of the posterior vitreous cortex.

MAIN OUTCOME MEASURES

Status of macular edema, visual acuity, and complications.

RESULTS

Ten eyes (56%) improved 2 or more lines of Snellen visual acuity within 12 months. Six eyes (33%) remained unchanged, within a line of preoperative Snellen visual acuity, and two eyes (11%) worsened by 2 or more lines of Snellen visual acuity. Slit-lamp biomicroscopy showed that cystoid macular edema had resolved in 14 eyes (78%) within 9 months postoperatively. One eye (6%) had minimal edema, whereas three eyes (17%) remained unchanged biomicroscopically at the final visit. Postoperative complications included cataract formation, glaucoma, optic nerve atrophy, epiretinal membrane formation, and tractional retinal detachment. No severe postoperative inflammation was noted.

CONCLUSIONS

Pars plana vitrectomy seems to have a beneficial effect on cystoid macular edema caused by sarcoidosis resistant to medical treatment.

Transcriptional silencing of Cyclooxygenase-2 by hyper-methylation of the 5' CpG island in human gastric carcinoma cells

It has been well established that overexpression of Cyclooxygenase-2 (Cox-2) in epithelial cells inhibits apoptosis and increases the invasiveness of malignant cells, favoring tumorigenesis and metastasis. However, the molecular mechanism that regulates Cox-2 expression has not been well defined in gastric carcinoma. In this study, we examined whether the Cox-2 expression could be regulated by hyper-methylation of the Cox-2 CpG island (spanning from -590 to +186 with respect to the transcription initiation site) in human gastric carcinoma cell lines. By Southern analysis, we found that three gastric cells (SNU-601, -620, and -719) without Cox-2 expression demonstrated hyper-methylation at the Cox-2 CpG island. A detailed methylation pattern using bisulfite sequencing analysis revealed that all of the CpG sites were completely methylated in SNU-601. Treatment with demethylating agents effectively reactivated the expression of Cox-2 and restored IL-1beta sensitivity in the previously resistant SNU-601. By transient transfection experiments, we demonstrate that constitutively active Cox-2 promoter activities were exhibited even without an exogenous stimulation in SNU-601. Furthermore, when the motif of the nuclear factor for interleukin-6 expression site, the cyclic AMP response element, or both was subjected to point mutation, the constitutive luciferase activity was markedly reduced. In addition, Cox-2 promoter activity was completely blocked by in vitro methylation of all of the CpG sites in the Cox-2 promoter region with SssI (CpG) methylase in SNU-601. Taken together, these results indicate that transcriptional repression of Cox-2 is caused by hyper-methylation of the Cox-2 CpG island in gastric carcinoma cell lines.

A monoclonal antibody against the glutaraldehyde-conjugated polyamine, putrescine: application to immunocytochemistry

We developed a mouse monoclonal antibody (mAb; APUT-32, IgG1 subisotype mAb) against putrescine (Put) conjugated to bovine serum albumin using a glutaraldehyde (GA)-sodium borohydride procedure, for applications in immunocytochemistry (ICC). The antibody specificity was evaluated by an ELISA binding test, simulating the ICC of tissue sections. APUT-32 mAb was highly specific to Put, and distinguished alterations in the chemical structure of other polyamine (PA) analogs, showing 3.8% crossreaction with cadaverine, 3.3% with spermidine (Spd), and 2.3% with 1,3-diaminopropane. Comparable results in immunoreactivity of APUT-32 mAb were obtained with the ELISA inhibition test. By the indirect immunoperoxidase method using the APUT-32 mAb, Put-like immunoreactivities were observed in the cytoplasm of HeLa and MCF-7 cell lines fixed with GA in combination with NaBH4 reduction, but almost no immunoreaction was seen in the cytoplasm of the human melanoma BD cell line. On the other hand, the same method but using a previously prepared ASPM-29 mAb, specific for spermine (Spm) and Spd, produced intense immunostaining in the cytoplasm of all the three cell types. The Put-like immunoreaction was completely abolished by absorption of the APUT-32 mAb with 10 microg/ml Put-human serum albumin conjugate prepared using GA and NaBH4. HPLC analysis was also performed for the levels of each of the PAs in the three types of cell, showing that the levels of Put detected were much lower than those of Spm and Spd, and were strikingly different in the three cell lines among which the human melanoma BD cell line contained the lowest levels of Put. These results strongly suggest that APUT-32 mAb reacts specifically with Put in the tumor cells and therefore has the potential as a new tool for elucidating the biological roles of Put in cells and tissues.

A patient with type I CD36 deficiency whose myocardium accumulated 123I-BMIPP after 4 years

A 73-year-old man with aortic regurgitation was examined by 123I-alpha-methyl-p-iodophenylpentadecanoic acid (BMIPP) myocardial single photon emission computed tomography (SPECT) in 1995. Myocardial accumulation was not evident on either the early or the delayed image obtained 15 minutes and 3 hours, respectively, after injecting 123I-BMIPP. Flow cytometric analysis of CD36 expression in monocytes and platelets identified a type I CD36 deficiency. The patient was hospitalized for severe heart failure in 1999. Upon admission, the cardiothoracic ratio on chest X-rays was 73%, and the left ventricular end-diastolic diameter on echocardiograms was enlarged to 77 mm. On the second day, we performed 123I-BMIPP myocardial SPECT. Myocardial accumulation was evident in the delayed, but not in the early image. We repeated 123I-BMIPP myocardial SPECT on the 10th day after admission. Myocardial accumulation was evident on both early and delayed images. 99mTc-tetrofosmin myocardial SPECT was immediately performed after 123I-BMIPP myocardial SPECT to distinguish myocardial from pooling images in the left ventricle, but, because the images from both 99Tc-tetrofosmin and 123I-BMIPP myocardial SPECT were idential, we considered that the 123I-BMIPP myocardial SPECT images reflected the actual myocardial condition. The CD36 molecule transports long-chain fatty acid (LCFA) on the myocardial membrane, but 123I-BMIPP scintigraphy does not show any myocardial accumulation in patients with type I CD36 deficiency, indicating that myocardial LCFA uptake occurs through CD36 on the human myocardial membrane. Even though our patient had type I CD36 deficiency, BMIPP was uptaken by the myocardium during heart failure, suggesting a variant pathway on the human myocardial membrane for LCFA uptake.

Ossification of the acetabular labrum

We report a rare case of extensive ossification of the unilateral acetabular labrum in a 40-year-old man. Radiological manifestations of diffuse skeletal hyperostosis were not found in the spine.

Fluorescent cyclodextrin immobilized on a cellulose membrane as a chemosensor system for detecting molecules

Dansyl glutamate-modified cyclodextrin (DnsGlu-beta-CD) was prepared as a fluorescent host, which is capable of being immobilized on a cellulose membrane (DnsGlu-beta-CD-membrane). The fluorescence intensity of DnsGlu-beta-CD decreased with increasing concentration of guest molecules, indicating that the host changes the location of the dansyl group from inside to outside the cyclodextrin cavity upon guest accommodation. Similar guest-induced decrease in the fluorescence intensity was observed for DnsGlu-beta-CD immobilized to a cellulose membrane. This result demonstrates that the cellulose membrane may be used as a practical supporting material of various chromophore-modified cyclodextrins and that DnsGlu-beta-CD-membrane is useful as a novel disposable chemosensor for molecules.

Multicenter prospective nonrandomized study of long-term antiarrhythmic drug therapy in patients with tachyarrhythmias: Japanese Antiarrhythmics Long-Term Study-2 (JALT-2 Study)

Based on the results of the Cardiac Arrhythmia Suppression Trial (CAST), strategies for the treatment of tachyarrhythmias have changed rapidly. The Japanese Antiarrhythmics Long-Term (JALT) study was planned to investigate the present methods for choosing antiarrhythmic drugs, and the effects on long-term prognosis in patients with tachyarrhythmias in Japan. Following a 6-month preliminary study (JALT-1), there was a multicenter nonrandomized prospective study (JALT-2), with a 2-year follow-up, of patients with paroxysmal atrial fibrillation (PAF), sustained ventricular tachycardia (SVT) and nonsustained VT (NSVT). Four hundred fifty-five patients were registered, and 361 of them (79%) were analyzed. Cerebral infarction occurred in 10 of 193 patients (5.2%) with PAF. Transition to chronic AF was observed in 21 patients (10.9%), but in none of the patients receiving Ca antagonist therapy. Twenty-five patients died: 5 deaths were arrhythmic, 10 were because of pump failure, and 9 were noncardiac. The most significant difference in drug selection between JALT-1 and JALT-2 was the increase in the use of slow kinetic Na channel blockers for PAF and the decrease in the use of the same agents for VT in the JALT-2 study. A marked change of therapeutic strategy occurred in JALT-2 compared with JALT-1. Most patients with a poor prognosis had underlying heart diseases and heart failure, but the per annum rate of death by arrhythmia and pump failure in JALT-2 was less than that in JALT-1.

Cerebrospinal fluid and serum neuron-specific enolase levels after febrile seizures

PURPOSE

Neuron-specific enolase (NSE) has been established as a reliable marker of neuronal damage in various neurologic disorders. The aim of this study was to evaluate whether febrile seizures (FS) cause brain damage, based on the serum and cerebrospinal fluid (CSF) levels of NSE.

METHODS

Fifty-three patients aged from 6 months to 7 years were enrolled. Among them, 36 patients had generalized seizures, and 17 had partial seizures. The maximal seizure duration was 90 min. Blood and CSF samples for measurement of NSE were obtained immediately after the seizure. NSE was measured using an enzyme immunoassay (EIA).

RESULTS

Serum and CSF levels of NSE ranged up to 10 ng/mL, but very high levels were not observed. In patients with partial seizures, the NSE level in the CSF and the ratio of the CSF to serum NSE levels showed a strong correlation with seizure duration. Conversely, there were no correlations between NSE levels and seizure duration in the patients with generalized seizures.

CONCLUSIONS

These results indicate that FS seldom cause severe neurologic damage, but prolonged partial seizures may cause slight neuronal injury.

Haematopoietic progenitor cells from the common marmoset as targets of gene transduction by retroviral and adenoviral vectors

To establish a new non-human primate model for human cytokine and gene therapy, we characterized lymphocytes and haematopoietic progenitor cells of the small New World monkey, the common marmoset. We first assessed the reactions of marmoset bone marrow (BM) and peripheral blood (PB) cells to mouse anti-human monoclonal antibodies (mAbs) for the purpose of isolating marmoset lymphocytes and haematopoietic progenitor cells. Both cell fractions stained with CD4 and CD8 mAbs were identified as lymphocytes by cell proliferation assay and morphological examination. Myeloid-specific mAbs such as CD14 and CD33 did not react with marmoset BM and PB cells. No available CD34 and c-kit mAbs could be used to purify the marmoset haematopoietic progenitor cells. Furthermore, we studied the in vitro transduction of the bacterial beta-galactosidase (LacZ) gene into CFU-GM derived from marmoset BM using retroviral and adenoviral vectors. The transduction efficiency was increased by using a mixed culture system consisting of marmoset BM stromal cells and retroviral producer cells. It was also possible to transduce LacZ gene into marmoset haematopoietic progenitor cells with adenoviral vectors as well as retroviral vectors. The percentage of adenovirally transduced LacZ-positive clusters was 15% at day 4 (multiplicity of infection=200), but only 1-2% at day 14. The differential use of viral vector systems is to be recommended in targeting different diseases. Our results suggested that marmoset BM progenitor cells were available to examine the transduction efficiency of various viral vectors in vitro.

Films of collagen crosslinked by S-S bonds: preparation and characterization

Collagen (type I from calf-skin) was chemically modified by 4-butyrothiolactone to obtain the mercapto group-bearing collagen (collagenSH), which possessed SH groups in 8-19 M% of a total amino acid residues. The triple helical strands of the collagen was not completely perturbed to exhibit the rotary dispersion [theta]221, which was as much as 70% of an original intensity of the collagen. In the presence of the oxygen dissolved in water, the collagenSH was cross-linked by disulfide bonds to afford the collagenSS. The collagenSS could preserve about 15 and 40% of an original helix structure at 55-70 degrees C and in 2mm sodium dodecyl sulfate, respectively. The film made of the collagenSS exhibited the tensile strength as high as 36 MPa and was insoluble in most organic solvents including water. The collagenSS film was more resistant to degradation by collagenase (type I) than the collagen film. The collagenSS film supported the growth of L929 fibroblast cell in a manner similar to a collagen film.

Phenotypic and functional characteristics of FIV infection in the bone marrow stroma

Human (HIV) and feline (FIV) immunodeficiency virus has been reported to infect bone marrow (BM) and stroma, followed by a loss in normal hematopoiesis. However, the magnitude and nature of HIV and FIV pathogenesis of the BM/stromal network are still unclear. In the current studies, pathogenesis of stromal cells was evaluated using the FIV model. Fourteen specific-pathogen-free cats inoculated with the four different strains (FIV(UK8), FIV(Bang), FIV(Shi), or FIV(Pet)) were monitored for FIV infection in the peripheral blood mononuclear cells (PBMC), BM cells, and stromal cells. All inoculated cats became positive for FIV in the PBMC by 7 weeks p.i. and 13 of 14 cats had FIV in the BM cells by 7-13 weeks p.i. FIV was detected in macrophages and stromal fibroblasts from FIV(UK8)-, FIV(Bang)-, and FIV(Shi)-infected cats but not from FIV(Pet)-infected cats and only transiently in cells from FIV(Shi)-infected cats. The ability of the supernatants from FIV-infected stromal cells to sustain the growth of uninfected BM cells was decreased 35-46% when compared to the supernatants from uninfected stromal cells. These results suggest that the FIV infection of the stroma alters normal hematopoietic function(s) and that the infected stromal cells can also serve as a reservoir for FIV infection.

Carvedilol enhances atrial and brain natriuretic peptide mRNA expression and release in rat heart

To clarify the role of the natriuretic peptide (NP) system in the myocardial protective effects of carvedilol, a beta-blocking agent, we investigated the effects of carvedilol on the NP system in the rat heart. After oral administration of carvedilol (low-dose group: 2 mg/kg/day, group C2; high-dose group: 20 mg/kg/day, group C20) for 1 week, plasma rat atrial NP (r-ANP), atrial mRNA levels of ANP, left ventricular mRNA of brain NP (BNP), NP receptor-A and NP receptor-C (NPR-C) (as a clearance receptor) were measured. Values were compared with those in vehicle-treatment rats (group V). The concentration of r-ANP was significantly higher in group C2 (135 +/- 9 pg/ml) and group C20 (161 +/- 11 pg/ml) than group V (75 +/- 6 pg/ml; both p < 0.01). ANP and BNP mRNA levels were significantly increased and NPR-C was significantly down regulated in group C2 (151 +/- 7, 120 +/- 8 and 78 +/- 7%, respectively, vs. group V) and group C20 (164 +/- 8. 133 +/- 7 and 72 +/- 8%, respectively, vs. group V) compared with group V (all p < 0.01). These results suggest that not only a high dose, but a low dose of carvedilol has the effect of increasing plasma ANP and BNP levels. This effect was closely related to the upregulation of ANP and BNP mRNA expression, and the down regulation of NPR-C mRNA expression in the heart. These mechanisms seem to account for a sizable portion of the protective effect of carvedilol for heart diseases.

Intact LTP and fear memory but impaired spatial memory in mice lacking Ca(v)2.3 (alpha(IE)) channel

To investigate the functional roles of the Ca(v)2.3 (alpha(1E)) channel in hippocampal CA1 pyramidal neurons, we studied in vitro synaptic properties and in vivo behaviors of the Ca(v)2.3 gene deficient mice. The Ca(v)2.3 channel mRNA was identified in the hippocampal formation of the wild-type mouse by in situ hybridization. The basic excitatory synaptic transmission and long-term potentiation by theta-burst stimulation were intact in CA1 region of Ca(v)2.3-/- mice. We performed two forms of behavioral tests to examine the hippocampus-dependent function, i.e., emotional and spatial learning tests. The Ca(v)2.3-/- mice were able to establish and maintain fear memories. Although general improvement in the performance of Morris water maze test was seen in Ca(v)2.3-/- mice, they displayed an obvious impairment in the probe test. These results suggest that the Ca(v)2.3 channel plays some role in formation of the accurate spatial memory but not of the fear memory.

Thiolated dermal bovine collagen as a novel support for bioactive substances--conjugation with lysozyme

Thiol groups were introduced to dermal bovine collagen (DBC) by the reaction with gamma-thiobutyrolactone. Thiolated DBC reacted with 2-pyridyl disulfide group introduced to lysozyme to form DBC-lysozyme conjugate through disulfide bridge. The enzymatic activity of freshly prepared conjugate was almost unchanged during ten consecutive runs over one month. The DBC-lysozyme conjugate showed the maximum activity at pH 6.3, on the contrary, that of native lysozyme was pH 9.0. Thermal stability of lysozyme was enhanced by the conjugation with DBC. The present results showed that the conjugation using thiolated collagen could be one of the useful alternative approaches to modify collagen with bioactive molecules.

Perioperative ventricular arrhythmias in patients undergoing partial left ventriculectomy

BACKGROUND

Although incidence of ventricular arrhythmias after partial left ventriculectomy (PLV) has been reported, there are no studies comparing incidence before and after PLV. Although operative scars may give rise to arrhythmias, improved energetic efficiency after PLV may decrease their incidence.

METHODS

Pre- and postoperative ventricular arrhythmias were monitored by Holter ECG and analyzed in 17 patients undergoing PLV in Curitiba, Brazil.

RESULTS

Although total 24-hour heart beat (THB) increased significantly (p = 0.018), ventricular premature contractions (VPCs) decreased markedly (p = 0.036), excluding one patient dying in low cardiac output (LOS) who had terminal arrhythmias increased multifold. In the remaining 16 patients, VPC pairs were also reduced significantly on the average (p = 0.038). In contrast, ventricular tachycardia (VT; more than three consecutive VPCs) disappeared in five patients, decreased in two patients, and newly occurred in four patients, with five patients showing no change; one of them developed a prolonged VT, successfully reversed by external cardioversion.

CONCLUSIONS

Despite notable significant increase in THB immediately after PLV, PVC and PVC pairs were significantly decreased in contrast to VT, which disappeared in some patients and newly occurred in other patients, remaining constant on the average. Sustained VT occurring in a patient with all other arrhythmias suppressed may suggest a unique electrophysiological substrate, may justify prophylactic use of amiodarone or an implantable cardioverter-defibrillator, and may underscore the importance of further and extended studies.

XANES analyses of silicon crystalline irradiated by nitrogen/oxygen ions

X-ray absorption techniques have been applied to the characterization of 5 keV nitrogen / oxygen ions implanted silicon samples. The depth selective measurement of XANES by recording in PEY mode and the quantitative analysis by superposition of XANES spectra were carried out to elucidate the depth profile of implanted ions. It has been revealed that the silicon nitride phase were formed in silicon after prolonged N+ irradiation and it extended over the deep part of the damaged region from the surface. On the other hand, for the O+ irradiation, silicon dioxide phase were produced only in the shallow part of the damaged region, i.e., the silicon dioxide phase likely broke off during the irradiation.

Molecular mechanisms for alpha2-adrenoceptor-mediated regulation of synoviocyte populations

The sympathetic nervous system has been indicated to influence the severity of inflammatory disease including rheumatoid arthritis. In this study, we elucidated the effects of catecholamine on the synovial cell populations. Stimulation with epinephrine or norepinephrine for 1-2 weeks dose- and time-dependently increased the number of synovial A (macrophage-like) cells but decreased that of B (fibroblast-like) cells. These responses in A and B cells were inhibited by the alpha2-antagonist yohimbine, the G-protein inactivator pertussis toxin and the phospholipase C (PLC) inhibitor U-73122. Furthermore, the protein kinase C (PKC) inhibitor calphostin C and mitogen-activated protein (MAP) kinase inhibitors PD98059 and wortmannin also abolished the norepinephrine effects on A and B cell numbers. In A cells cloned from an A and B cell mixture, norepinephrine also increased the cell number. In immunoblotting and immunocytostaining analyses, among the PKC isozymes, only PKC betaII immunoreactivity was observed in the cytoplasm of unstimulated A and B cells. After alpha2-adrenoceptor stimulation, PKC betaII immunoreactivity increased in the plasma membranes of both A and B cells with decreases in the cytoplasm. These findings indicated that alpha2-adrenoceptor stimulation of type A and B synoviocytes produced an increase and a decrease in the respective cell number, probably through Gi-coupled PLC activation and the resulting stimulation of the PKC betaII/MAP kinase.

Sites of asparagine-linked oligosaccharides in porcine 32 kDa enamelin

The 32 kDa enamelin protein isolated from developing porcine enamel was previously shown to contain eight different asparagine-linked oligosaccharides. However, only three consensus attachment sites were evident in this protein. In this study, glycopeptides containing all three potential glycosylation sites (72-Asn, 79-Asn and 91-Asn) were purified from 32 kDa enamelin. The oligosaccharides were isolated from each glycopeptide following digestion with N-oligosaccharide glycopeptidase, labeled with 2-aminopyridine at the reducing ends, and then characterized by reverse phase HPLC. All three potential sites were found to be glycosylated heterogeneously (i.e., five biantennary complexes at 72-Asn, two biantennary complexes at 79-Asn, three triantennary complexes at 91-Asn), accounting for all eight oligosaccharides characterized previously. These results indicate that 32 kDa enamelin has a complex pattern of asparagine-linked glycosylation localized within a small region (20 residues) of the protein. The functional significance of this glycosylation remains to be established.

High-porosity expanded polytetrafluoroethylene grafts for thoracic vena cava replacement with or without an omentum wrap

We previously reported that, in a short-term thoracic inferior vena cava (IVC) replacement, a high-porosity expanded polytetrafluoroethylene (ePTFE) graft (fibril length 60 microm) performed well without altering the short-term patency, and that the healing of the high-porosity ePTFE graft was accelerated by an omentum wrap. The purpose of this study was to examine the long-term performance of the high-porosity ePTFE graft with or without an omentum wrap. Eighteen grafts were placed as a thoracic IVC replacement in dogs. Nine of the grafts were wrapped in an omental pedicle flap while the other 9 were not. At 1 month and 6 months, the grafts were harvested and examined for a pathological analysis. During the observation period, one dog died of a viral infection, while the other 17 dogs survived. At 1 month and 6 months, the patency rates of the 17 grafts were 100% regardless of the presence or absence of an omentum wrap. The healing of the grafts without omentum wrap was incomplete 6 months after implantation; granulation tissue was present in the center of the pseudointima. The grafts healed completely by the addition of an omentum wrap. Our data suggest that, with an omentum wrap, the high-porosity ePTFE graft is fully expected to show a good long-term function.

Degradation of enamel matrix proteins in porcine secretory enamel

To elucidate the progressive disappearance of 25 kDa amelogenin occurring in a narrow space near the surface of enamel, the alkaline soluble fraction which contained 80% of the total proteins was extracted from a newly formed porcine enamel. When this fraction was incubated with the addition of Ca ions in an in vitro system, the degradation of the coexisting amelogenin and enamelin occurred without activation during the incubation period. Although the fraction contained mainly two kinds of metalloproteinases, 56 kDa and 61 kDa gelatinolytic, and 41 kDa and 46 kDa caseinolytic activities, it was demonstrated on amelogenin enzymography that the caseinolytic one was concerned with the conversion of the 25 kDa amelogenin into the 20 kDa amelogenin. The protein distribution of the newly formed enamel indicated that the metalloproteinases degraded the coexisting enamelin and amelogenin imperfectly. Nevertheless, during the next developing stage they demonstrated their full activities. It is suspected that these activities are regulated by Ca ions, which may be increased by a cascade system.

Cyclooxygenase-2 stimulates production of amyloid beta-peptide in neuroblastoma x glioma hybrid NG108-15 cells

Cyclooxygenase (COX) synthesizes bioactive prostaglandins from arachidonic acid, and there are COX-1 and COX-2 isoforms with distinct pathophysiological functions. Recent studies demonstrated that COX-2 expression was up-regulated in the brain of patients with Alzheimer's disease. We established mouse neuroblastoma x rat glioma hybrid NG108-15 cells stably expressing human COX-2. The COX-2-expressing cells showed 3- to 4-fold increases in both COX activity and prostaglandin E(2) production. The mRNA level of amyloid precursor protein (APP) was elevated by approximately 2-fold in the COX-2-expressing cells compared with mock-transfected cells. Amyloid beta-peptide and a secreted form of APP, both derived from APP by proteolysis was also increased. Interestingly, neurite outgrowth was stimulated in the COX-2-expressing cells with concomitant reduction of the cell proliferation rate. A selective COX-2 inhibitor (JTE-522) and a nonselective COX inhibitor (indomethacin) suppressed production of amyloid beta-peptide and a secreted form of APP by inhibition of APP mRNA level, suggesting that COX-2 plays important roles in the neurodegenerative processes of Alzheimer's disease.