Up-regulation of P-glycoprotein expression by osmotic stress in rat sugar cataract

P-glycoprotein (P-gp), a plasma membrane protein, is thought to function in the export of cytotoxic drugs and to act as a modulator of chloride channels that regulate cell volume in many cell types. P-gp has been shown to play a role in lens volume regulation and initiation of osmotic cataract. We investigated the lenticular expression levels of P-gp in galactose-fed rats, an experimental model of sugar cataract. P-gp was overexpressed in lenses from galactose-fed rats with cortical sugar cataract, and in rat lens epithelial cells cultured in high-glucose medium. However, application of aldose reductase (AR) inhibitor was able to reverse the changes in P-gp levels in the lenses of galactose-fed rats, confirming the role of AR and involvement of the polyol pathway in cataract formation. Our findings suggest that P-gp may be induced by AR over-expression and/or osmotic stress, thus playing a regulatory role in maintaining lenticular osmotic balance in sugar cataract.

Site-controlled quantum dots fabricated using an atomic-force microscope assisted technique

An atomic-force microscope assisted technique is developed to control the position and size of self-assembled semiconductor quantum dots (QDs). Presently, the site precision is as good as ± 1.5 nm and the size fluctuation is within ± 5% with the minimum controllable lateral diameter of 20 nm. With the ability of producing tightly packed and differently sized QDs, sophisticated QD arrays can be controllably fabricated for the application in quantum computing. The optical quality of such site-controlled QDs is found comparable to some conventionally self-assembled semiconductor QDs. The single dot photoluminescence of site-controlled InAs/InP QDs is studied in detail, presenting the prospect to utilize them in quantum communication as precisely controlled single photon emitters working at telecommunication bands.

Expression of ecalectin, a novel eosinophil chemoattractant, in nasal polyps

CONCLUSION

Ecalectin, which is produced in the mucosa of nasal polyps, seems to play an important role in the accumulation and activation of eosinophils in nasal polyps, regardless of the presence or absence of atopic predisposition.

OBJECTIVE

Ecalectin is a recently discovered eosinophil chemoattractant which elongs to the galectin family. We investigated the expression of ecalectin in nasal polyp tissues associated with various nasal and paranasal diseases in order to clarify the pathogenesis of eosinophilia in nasal polyposis.

MATERIAL AND METHODS

Nasal polyps were taken from 56 patients diagnosed as having chronic sinusitis with nasal polyposis. The surgically resected polyps and nasal turbinates were immunohistochemically stained using antibodies against EG2, human mast cell tryptase, CD3 and ecalectin.

RESULTS

The number of EG2- and ecalectin-positive cells was significantly higher in nasal polyps than control turbinates. Ecalectin-positive cells were observed in the subepithelial layer, where many EG2-positive cells were present. The number of ecalectin-positive cells correlated significantly with the number of EG2-positive cells in nasal polyps. Many ecalectin mRNA-positive cells were also observed in nasal polyps with an accumulation of EG2-positive cells.

Few-electron molecular states and their transitions in a single InAs quantum dot molecule

We study electronic configurations in a single pair of vertically coupled self-assembled InAs quantum dots, holding just a few electrons. By comparing the experimental data of nonlinear single-electron transport spectra in a magnetic field with many-body calculations, we identify the spin and orbital configurations to confirm the formation of molecular states by filling both the quantum mechanically coupled symmetric and antisymmetric states. Filling of the antisymmetric states is less favored with increasing magnetic field, and this leads to various magnetic field induced transitions in the molecular states.

Developmental changes in oscillatory and slow responses of the rat accessory olfactory bulb

Field potential, patch-clamp and optical recordings were performed in accessory olfactory bulb slices of postnatal rats following single electrical stimulation of the vomeronasal nerve layer. On the basis of differences in the components of the field potential, postnatal days were divided into three periods: immature (until postnatal day 11), transitional (postnatal days P12-17) and mature periods (after postnatal day 18). During the immature period, vomeronasal nerve layer stimulation provoked a characteristic damped oscillatory field potential, and the field potential recorded in the glomerular layer consisted of a compound action potential followed by several periodic negative peaks superimposed on slow components. Reduction in [Mg2+] enhanced slow components but did not affect oscillation, whereas an NMDA receptor antagonist, D-2-amino-5-phosphonovalerate, depressed slow components but did not affect the oscillation. During the mature period, slow components and the periodic waves (oscillation) disappeared. The time course of the field potential was similar to that in adults, suggesting that the accessory olfactory bulb reached electrophysiologically maturity at postnatal day 18. A non-NMDA receptor antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione, inhibited vomeronasal nerve layer-induced responses, while D-2-amino-5-phosphonovalerate had no effect, suggesting that NMDA and non-NMDA receptors are active in immature tissues, whereas non-NMDA receptors predominated in mature tissue. Results from whole-cell patch recordings in mitral and granule cells yielded results consistent with those from field potential and optical recordings. Further, a gradual decrease in number and frequency of oscillating waves was observed until postnatal day 17. Analyses of the depth profile of field potentials and current source density in immature tissue suggested that the oscillation and slow components originated in the glomerular layer but not in the external plexiform/mitral cell layer. Further, a new type of oscillation, which was independent of the reciprocal dendrodendritic synapses between mitral and granule cells, was detected. These data indicate that the lack of oscillatory suppression by immature NMDA receptors may play a critical role in the dynamic alteration of bulbar conditions.

Effect of suplatast tosilate on goblet cell metaplasia in patients with asthma

BACKGROUND

Goblet cell metaplasia is a pathologic characteristic of asthma, associated with excess mucus secretion. Interleukin (IL)-4 and IL-13 plays an important role in mucus hypersecretion. Suplatast tosilate (suplatast), an antiallergic agent, is a Th2 cytokine inhibitor that suppresses the synthesis of IL-4, IL-5, IL-13, and eosinophilic airway inflammation.

OBJECTIVE

We examined the effects of suplatast on mucus production in bronchial biopsy specimens taken from asthmatic subjects.

METHODS

Oral suplatast 300 mg daily, or placebo was administered for 3 months in a double-blind, parallel-group study in 25 patients with asthma. Biopsy specimens were evaluated at before and after treatment for alcian blue/period acid-Schiff (AB/PAS), MUC5AC staining in bronchial epithelium and IL-4+, IL-13+ cells as well as inflammatory cells in lamina propria.

RESULTS

There were significant decreases in the percentage of AB/PAS (P < 0.01) and MUC5AC (P < 0.01) stained area in the suplatast group. These changes were accompanied by significant decreases in IL-4+ and IL-13+ cells in suplatast-treated subjects. Additionally, we have observed that the number of infiltrating eosinophils and CD4+ T cells significantly decreased.

CONCLUSIONS

These findings suggest that suplatast prevents goblet cell metaplasia through modulation of Th2 cytokine production and the recruitment of eosinophils and CD4+ T cells in the asthmatic airways.

In vitro selective suppression of feline myeloid colony formation is attributable to molecularly cloned strain of feline leukemia virus with unique long terminal repeat

Molecularly cloned feline leukemia virus (FeLV)-clone 33 (C-33), derived from a cat with acute myelocytic leukemia (AML), was examined to assess its relation to the pathogenesis of AML and myelodysplastic syndrome (MDS). To evaluate in vitro pathogenicity of FeLV C-33, bone marrow colony-forming assay was performed on marrow cells infected with FeLV C-33 or an FeLV subgroup A strain (61E, a molecularly cloned strain with minimal pathogenicity). The myeloid colony-forming activity of feline bone marrow mononuclear cells infected with FeLV C-33 was significantly lower than that of cells infected with 61E. This suggests that FeLV C-33 has myeloid lineage-specific pathogenicity for cats, and that FeLV C-33 infection is useful as an experimental model for investigating pathogenesis of MDS and AML.

Odor-concentration coding in the guinea-pig piriform cortex

By optical imaging of intrinsic signals, we demonstrated a possible code for odor concentration in the anterior piriform cortex of the guinea-pig. Odor-induced cortical activation, which primarily originated in layer II, appeared in a narrow band beneath the rhinal sulcus over the lateral olfactory tract, corresponding to the dorsal part of the anterior piriform cortex. Lower concentrations activated the rostral region of the band, whereas higher ones generated caudally spreading activation, and the site at which neural activation reached its maximum extent depended upon odor concentration. Different odors with low concentrations generated distinct but somewhat overlapping patterns in the rostral region of the band; the limited extent of cortical activity may be one focal domain for each odor. It was hard to judge, however, that odor-specific domains appeared in the anterior piriform cortex, because the strong stimuli induced largely overlapping patterns. Furthermore, the total area activated increased in proportion to concentrations raised to a power of 0.5-0.9. Importantly, these imaging results were confirmed with unit recordings which indicated a rostro-caudal gradient in odor-sensitivity among cortical neurons. Our results suggest that the dorsal part of the anterior piriform cortex may be associated with odor concentration. Therefore, in addition to recruitment of more olfactory sensory cells and glomeruli in response to stronger stimuli, a rostro-caudal gradient in axonal projections from mitral/tufted cells and/or in association fibers may play an important role in odor-concentration coding in the anterior piriform cortex.

The effect of complement regulatory protein expression on pig endothelial cells to porcine endogenous retrovirus lyses by human sera

INTRODUCTION

Expression of human complement regulatory proteins (CRP) on pig endothelial cells (PEC) has been useful to avoid hyperacute rejection by human sera. On the other hand, porcine endogenous retrovirus (PERV) from PEC transfectants with CRP may acquire resistance to human sera. In this study, we investigated the effects of the transfected CRP on PERV neutralization and/or lysis by human sera.

METHODS

cDNA of membrane cofactor protein (MCP: CD46), decay accelerating factor (DAF: CD55), and CD59 were transfected to PEC lines by lipofection. The expressions of these CRPs were verified by FACS analysis. The PEC lines with human CRPs were then transfected with the LacZ gene and PERV subtype B (PERV-B) to investigate PERV infectivity by LacZ pseudotype assay. Culture supernates of PEC were inoculated to HEK293 cells with or without 10% human sera. The inoculated 293 cells were then histochemically stained to count the LacZ-positive blue foci and calculated the rate of reduction of LacZ-positive cells by serum.

RESULTS

PERV from the PEC with DAF or CD59 showed a resistance to human sera compared with those of control PEC (DAF: 59.6% +/- 5.3%, CD59: 61.1% +/- 3.9% vs control: 31.3% +/- 3.6%; P < .01). However, PEC with MCP did not cause such an effect (28.8% +/- 2.5%).

CONCLUSIONS

While expression of DAF and CD59 on PEC changed its PERV responsiveness to human sera, MCP did not improve it.

Anti-angiogenic potential of tocotrienol in vitro

Modulation of angiogenesis is now a recognized strategy for the prevention of various angiogenesis-mediated disorders. We investigated, using well-characterized in vitro systems, the anti-angiogenic property of vitamin E compounds, with particular emphasis on tocotrienol, a natural analog of tocopherol. Tocotrienol, but not tocopherol, inhibited the proliferation of bovine aortic endothelial cells in dose dependent manner at half-maximal concentrations in the low micromolar range. Tocotrienol also significantly inhibited the formation of networks of elongated endothelial cells within 3D collagen gels. From these results, we suggest that tocotrienol is a potential candidate for the development of useful therapeutic agents or preventive food factors for tumor angiogenesis.

Single-dot spectroscopy via elastic single-electron tunneling through a pair of coupled quantum dots

We study the electronic structure of a single self-assembled InAs quantum dot by probing elastic single-electron tunneling through a single pair of weakly coupled dots. In the region below pinch-off voltage, the nonlinear threshold voltage behavior provides electronic addition energies exactly as the linear, Coulomb blockade oscillation does. By analyzing it, we identify the s and the p shell addition spectrum for up to six electrons in the single InAs dot, i.e., one of the coupled dots. The evolution of the shell addition spectrum with magnetic field provides Fock-Darwin spectra of the s and p shells.

A novel antigenic variant of Canine parvovirus from a Vietnamese dog

Nine isolates of Canine parvovirus (CPV) were obtained from Vietnamese dogs and cats. One canine isolate showed a unique antigenic property which indicates a novel antigenic variant of CPV-2b when examined with hemagglutination inhibition tests using our monoclonal antibodies, 21C3 and 19D7, which were recently developed. This isolate had an amino acid substitution of residue 426, Asp to Glu, and the same substitution has recently been found in CPV from Italian dogs. This study first showed that such substitution caused an antigenic difference demonstrable by monoclonal antibodies and that a similar evolution may have occurred in CPV in Vietnam.

Focal brain edema and natriuretic peptides in patients with subarachnoid hemorrhage

Central salt wasting syndrome may be caused by pathological increases in serum natriuretic peptides after subarachnoid hemorrhage (SAH). However, it is unclear as to why the serum concentration of atrial natriuretic peptide (ANP) or brain natriuretic peptide (BNP) increases in the subacute phase of SAH. The present study was designed to assess the correlation between focal brain edema and serum concentration of ANP or BNP in patients with SAH. Focal brain edema was found in 8 SAH-patients and peaked between days 4 and 7 of SAH. The mean serum ANP and BNP levels in patients with focal brain edema were significantly higher than those in patients without focal brain edema between days 4 and 14 of SAH. These results suggest that focal brain edema might correlate with increased levels of ANP and BNP in the subacute phase of SAH.

Vascular endothelial growth factor expression in pituitary adenomas

Vascular endothelial growth factor (VEGF) is known to be a mediator of angiogenesis and vascular permeability. A cystic component and hemorrhage are often found in pituitary adenomas. In the present study we assess the VEGF expression based on immunohistochemical examinations in 48 pituitary adenomas. All the adenomas showed some VEGF immunoreactivity mainly in the cytoplasm of tumor cells. Of the 48 adenoma-cases, 16 cases had a strong VEGF immunoreactivity, 26 cases had a moderate one, and 6 cases had a weak one. On the MR images, a cystic component was found in 16 cases (33.3%), and a hemorrhage was found in 18 cases (37.5%). The VEGF immunoreactivity had a significant relationship with the cystic component but neither the hemorrhage, size, recurrence, or HE classification. These findings suggest that VEGF might play a potential role in the pathogenesis of cystic formation in pituitary adenomas.

Characteristic phosphorylation of the extracellular signal-regulated kinase pathway after kainate-induced seizures in the rat hippocampus

Extracellular signal-regulated kinase (ERK) pathways play a crucial role in cell growth and long-lasting neuronal plasticity. Several studies have shown that phosphorylated-ERK (p-ERK) significantly increases after kainic acid (KA) administration. However, little or no information is available about the spatial distribution of p-ERK after KA-induced seizures. We herein show that KA-induced seizures significantly increase p-ERK in both neurons and astrocytes in rat brain using Western blots and immunohistochemistry. A strong immunoreactivity for p-ERK was induced in the dentate hilar neurons and CA3 neurons 30 mins and 6 hrs after KA injection. In addition, immunoreactivity for p-ERK was seen in astrocytes 6 hrs after KA injection. 72 hrs after KA injection, all pyramidal neurons had died. These findings suggest that the ERK pathway participates in the KA-induced neurotoxicity in the rat hippocampus.

Mitogen-activated protein kinases phosphorylation in posttraumatic selective vulnerability in rats

Mitogenic stimulation of the Mitogen-activated protein kinase (MAPK) pathway modulates the activity of many transcriptional factors leading to biological responses. Of these, three MAPK cascades are well characterized as extracellular signal-regulated protein kinase (ERK), c-Jun NH(2)-terminal kinase (JNK), and p38 pathways. The aim of this study was to investigate the topographic distribution and the role of activated MAPK pathways after fluid percussion injury (FPI) in rats. In the present results, FPI significantly induced ERK- and JNK-phosphorylation, but not p38-phosphorylation in the cortex and hippocampus at the injury site. The immunoreactivity for phospho-ERK was localized in the superficial neuronal layers, dentate hilar neurons, and the damaged CA3 neurons after 30 mins of FPI. Double immunostaining showed that phospho-ERK was prominent in astrocytes 6 hrs after TBI. The current results suggest that MAPK pathways are involved in signal transduction after FPI.