Coordination of microtubules and the actin cytoskeleton is important in osteoclast function, but calcitonin disrupts sealing zones without affecting microtubule networks

Bone-resorbing osteoclasts form sealing zones and ruffled borders toward the bone surface. The sealing zone consists of a ring-like alignment of F-actin dots and surrounds the ruffled border, from which protons are secreted into the bone surface. Vacuolar-type proton ATPase (V-ATPase) in osteoclasts is a ruffled border-associated enzyme responsible for the proton secretion. We studied the interaction between microtubules and the actin cytoskeleton in osteoclasts. Confocal microscopic observation revealed that osteoclasts on glass coverslips, dentine slices and Osteologictrade mark discs formed the ring-like structure of F-actin dots, and microtubules overlapped the top of the F-actin dots. Osteoclasts cultured on dentine formed resorption pits within 48 h. The treatment of osteoclasts with cytochalasin D, an F-actin-depolymerizing reagent, induced perturbation of the microtubules in osteoclasts on glass and inhibited their pit-forming activity on dentine in a dose-dependent and reversible manner. Conversely, nocodazole, a microtubule-depolymerizing reagent, disrupted sealing zones and inhibited pit-forming activity of osteoclasts in a dose-dependent and reversible manner. V-ATPase showed a tendency to be localized inside sealing zones in osteoclasts. Treatment of osteoclasts with calcitonin induced both disruption of sealing zones and dispersion of V-ATPase to the whole area of the cytoplasm within 60 min. The microtubule networks in osteoclasts remained unchanged for 60 min even in the presence of calcitonin. These results suggest that coordination of the actin cytoskeleton and microtubules is important in the function of osteoclasts, but calcitonin selectively affects the actin cytoskeleton and induces the dispersion of V-ATPase without causing significant changes in the microtubules.

Effects of calcitonin on the function of human osteoclast-like cells formed from CD14-positive monocytes

Calcitonin inhibits bone-resorbing activity of osteoclasts. Expression of mRNA of calcitonin receptor (CTR) and its related proteins was examined in human osteoclasts and their progenitors. CD14-positive (CD14 + macrophages) in the monocytes prepared from human peripheral blood cells differentiated into macrophages (CD14 +) presence of macrophage colony-stimulating factor (M-CSF) or into osteoclast-like cells (OCLs) in the presence of M-CSF plus receptor activator of NFkappaB ligand. CD14 macrophages expressed mRNA of CTR-like receptor (CRLR), receptor activity modifying protein (RAMP) 1, RAMP2, and RAMP3, but not CTR. In contrast, OCLs expressed mRNA of CTR but not CRLR or RAMPs. Human OCLs cultured on dentine slices formed actin rings (corresponding to clear zones) and resorption pits on the slices. Calcitonin disrupted actin rings and inhibited the pit-forming activity of OCLs. CTR is known to couple to cAMP-dependent protein kinase (PKA) and protein kinase C (PKC). The effect of calcitonin on actin ring disruption was partially blocked by adding H-7, an inhibitor of both PKA and PKC. Both forskolin, an activator of PKA, and phorbol myristate, an activator of PKC, disrupted actin rings in OCLs. These results suggest that both PKA- and PKC-mediated signals are involved in calcitonin-induced inhibition of human OCL function.

Evaluation of sample spin-polarization from spin-polarized scanning tunneling spectroscopy experiments

Spin-polarized scanning tunneling microscopy has produced a great amount of images presenting magnetic contrast between different magnetic domains with an unsurpassed spatial resolution but getting values like the surface polarization has proven to be a difficult task. We will discuss in detail how to extract this information for the case of manganese layers grown on Fe(001) whiskers. Mn layers adopt a body-centered-tetragonal (bct) structure when they are grown on the Fe(001) surface at room temperature. The Mn layers show an antiferromagnetic coupling between the layers. Comparing our spin-polarized scanning tunneling spectra measured with Fe-coated W tips with spin-resolved band structure calculations, we are able to find the value of the sample surface polarization. Also discussed is a method to change the tip magnetization. Finally, the magnetic structure around a screw dislocation on the surface is reviewed.

Surgically-induced astigmatism following single-site phacotrabeculectomy, phacotrabeculotomy and advanced non-penetrating phacotrabeculectomy

We study surgically-induced astigmatism following three kinds of glaucoma surgeries combined with cataract surgery with 6 months of follow-up. The mean surgically-induced astigmatism at 6 months postoperatively was 1.92 +/- 1.87 diopters in phacotrabeculectomy (n = 45), 0.72 +/- 0.40 diopters in advanced non-penetrating phacotrabeculectomy (n = 40) and 0.76 +/- 0.47 diopters in phacotrabeculotomy (n = 49), which appeared to be stabilized by 3 months. Each group revealed a tendency of "with the wound" induced astigmatism. Phacotrabeculectomy could induce greater surgically-induced astigmatism than advanced non-penetrating phacotrabeculectomy and phacotrabeculotomy.

Histopathological safety evaluation of polyethylene glycol applied subcutaneously in mice

Polyethylene glycol is used as a non-aqueous solvent for a variety of medical agents. We believe it could also be used as a base component in root canal filling material and aimed to test the histological safety of subcutaneously injected polyethylene glycol. We injected polyethylene glycol subcutaneously into the dorsal area of 30 6-week-old anaesthetized male ddY mice. An equal number of mice were injected with propylene glycol as controls. One week, 3 weeks and 9 weeks after injection, the tissue surrounding the injection site was removed from 10 mice in each group and examined. We found no histopathological changes, degeneration, necrosis, foreign body reactions or granulation tissue proliferation in either group. Some inflammatory cell infiltration was observed in both groups. Based on these results, we believe that polyethylene glycol could be used safely as a base component of biomaterials for internal medical use, such as in root canal filling material.

Intracorneal hematoma with descemet membrane detachment after viscocanalostomy

PURPOSE

To describe a case of intracorneal hematoma with Descemet membrane detachment after viscocanalostomy.

DESIGN

Interventional case report.

METHODS

A 63-year-old with uncontrolled primary open-angle glaucoma underwent viscocanalostomy. During the introduction of hyaluronate 2.3% under the superficial flap, a limited lysis of Descemet membrane was observed.

RESULT

Slit-lamp biomicroscopy showed an intracorneal hematoma with Descemet membrane detachment 1 day after viscocanalostomy. The creation of an intentional break of Descemet membrane and descemetopexy using sulfur hexafluoride gas were performed. The cornea regained transparency after surgery.

CONCLUSIONS

Intracorneal hematoma with Descemet membrane detachment is a possible complication of viscocanalostomy.

Observation of spin-polarized surface states on ultrathin bct Mn(001) films by spin-polarized scanning tunneling spectroscopy

We report the observation of a magnetic contrast of up to 20% in the scanning tunneling spectroscopy dI/dV maps obtained with Fe-coated tips on Mn(001) layers grown on an Fe(001) whisker at 370 K. These nanometer resolution microscopy results show that the layers couple antiferromagnetically. By normalizing the dI/dV curves by tunneling probability functions, we found a spin-dependent peak on the body-centered-tetragonal (bct) Mn(001) surface at +0.8 V, whose high spin polarization gives rise to the dI/dV map contrast. Band structure calculations allow one to identify the +0.8 V peak as due to two spin-polarized d(z(2)) surface states.

Time-dependent changes in the carotenoid composition and preferential binding of spirilloxanthin to the reaction center and anhydrorhodovibrin to the LH1 antenna complex in Rhodobium marinum

Carotenoids were isolated from the cells of Rhodobium marinum, and their structures were determined by mass spectrometry and 1H nuclear magnetic resonance spectroscopy; the carotenoids include lycopene, rhodopin, anhydrorhodovibrin, rhodovibrin and spirilloxanthin. Time-dependent changes in the carotenoid composition in the reaction center (RC) and the light-harvesting complex 1 (LH1) were traced by high-performance liquid chromatography analysis of the extracts. The carotenoid composition changed according to the spirilloxanthin biosynthetic pathway. However, spirilloxanthin having the longest conjugated chain was always preferentially bound to the RC, and anhydrorhodovibrin and other precursors to the LH1.

Oxidative stress activates ATMPK6, an Arabidopsis homologue of MAP kinase

Mitogen-activated protein kinase (MAPK) cascades function in biotic and abiotic stress responses in plants. We analysed effect of oxidative stress on the activation of ATMPK6, an Arabidopsis thaliana MAPK, in Arabidopsis T87 cultured cells and rosette leaves using anti-ATMPK6 specific antibody. ATMPK6 in T87 cells was strongly activated by reactive oxygen species (ROS) such as H(2)O(2) and KO(2). In leaves, ATMPK6 was activated by paraquat and 3-amino-1,2,4-triazole (a catalase inhibitor). These results indicate that ATMPK6 is one of the candidates for signal mediators in response to abiotic or biotic sources for ROS in Arabidopsis.

Repression of starch degradation under anaerobic conditions by irregularly high levels of ATP in Chlamydomonas sp. MGA161

It is generally known that in green algal species the acceleration of starch degradation upon transition from aerobic to anaerobic conditions is a result of the Pasteur effect in glycolysis. However, the acceleration of starch degradation did not occur in cells of Chlamydomonas sp. MGA161. In MGA161 cells, the anaerobic ATP level, which decreased to about half of the aerobic ATP level in cells of Chlamydomonas reinhardtii after fermentation for 2 h, was kept higher than its aerobic ATP level. Gramicidin D, a monovalent cation ionophore, markedly decreased the anaerobic and aerobic ATP levels due to the increase in ATP demand, accompanied by the acceleration of starch degradation in MGA161 cells. Although the anaerobic ATP level of C. reinhardtii cells was partially decreased by gramicidin D, starch degradation did not accelerate markedly when compared with the result in MGA161 cells. Therefore, starch was degraded at nearly the maximum rate in C. reinhardtii cells under anaerobic conditions; in contrast, the high level of ATP in MGA161 cells repressed starch degradation even under anaerobic conditions, resulting in the absence of the Pasteur effect.

Electron-energy-loss near edge structures of six-fold-coordinated Zn in MgO

Electron-energy-loss near edge structures (ELNES) at the Zn-L(2,3) edge and the O-K edge have been measured for 10 mol% ZnO-doped MgO, and were compared with spectra from reference materials. In order to interpret the spectra, first principles molecular orbital calculations were made using model clusters composed of 125 and 153 atoms. Photoabsorption cross sections (PACS) were computed at the Slater's transition state in which a half-filled core hole was included in the self-consistent calculations. The difference in the coordination numbers of Zn was found well distinguishable by the Zn-L(2,3)-edge ELNES. The experimental spectra in the first 25 eV were well reproduced by the theoretical PACS. In this energy region, the Zn-L(2,3)-edge ELNES from four-fold coordinated Zn showed four sets of peaks, whereas the six-fold coordinated Zn exhibits three sets of peaks. The origin of these peaks can be explained by the point symmetry within the first coordination unit. A small shift toward the lower energy side was observed in the O-K edge ELNES of the ZnO-doped MgO as compared with pure MgO. This can be ascribed to the lower energy of the Zn-4s orbital as compared with the Mg-3s orbital, which is the common mechanism to the difference in the band gap between MgO and ZnO.

Coulometric titration of D(+)-glucose using its enzymatic oxidation

A definitive method is described for the indirect assay of milligram quantities of D(+)-glucose by coulometric titration. D(+)-Glucose was aerobically oxidized by glucose oxidase in an acetate buffer solution (pH 5.1). Subsequently, the enzymatically formed hydrogen peroxide was titrated coulometrically with electrogenerated hypobromite in sodium bromide-sodium tetraborate medium of pH 8.6, with biamperometric end-point detection. Parameters affecting the enzymatically catalyzed oxidation and coulometric titration were evaluated. The optimized conditions for the oxidation of up to 20 mg of D(+)-glucose include the addition of 4500 U of glucose oxidase and stirring over a 10-min interval at 25 degrees C. Under proposed conditions, the assay values of several commercial D(+)-glucose reagents were somewhat lower than the guaranteed minimum values, with RSDs (n = 5) of 0.071 - 0.106%.

Effect of bovine small intestine thioredoxin on aldose reductase activity

Under oxidative stress mediated by H(2)O(2), significant activation of purified aldose reductase from bovine small intestine was observed in the presence of purified thioredoxin from bovine small intestine.

Determination of functional regions of p125, a novel mammalian Sec23p-interacting protein

The Sec23p-Sec24p complex is a component of coat protein II-coated vesicles involved in protein export from the endoplasmic reticulum. We previously identified a novel Sec23p-interacting protein, p125, which consists of 1000 amino acids and comprises a proline-rich region and a phospholipase A(1) homology region. p125, when ectopically expressed in cultured cells, localizes to endoplasmic reticulum-Golgi intermediate regions. In the present study we showed that expressed p125 principally colocalizes with p115 and GM130, both of which are involved in vesicle tethering to Golgi membranes. Next, we determined the functional regions of p125 by expressing a p125 series with deletions. The results showed that the proline-rich region (residues 135-259) is responsible for the binding to Sec23p. For the correct localization of p125, a region (residues 135-1000) comprising both the proline-rich and phospholipase A(1) homology regions was required.

Various abiotic stresses rapidly activate Arabidopsis MAP kinases ATMPK4 and ATMPK6

Mitogen-activated protein kinase (MAP kinase, MAPK) cascades play pivotal roles in signal transduction of extracellular stimuli, such as environmental stresses and growth regulators, in various organisms. Arabidopsis thaliana MAP kinases constitute a gene family, but stimulatory signals for each MAP kinase have not been elucidated. Here we show that environmental stresses such as low temperature, low humidity, hyper-osmolarity, touch and wounding induce rapid and transient activation of the Arabidopsis MAP kinases ATMPK4 and ATMPK6. Activation of ATMPK4 and ATMPK6 was associated with tyrosine phosphorylation but not with the amounts of mRNA or protein. Kinetics during activation differ between these two MAP kinases. These results suggest that ATMPK4 and ATMPK6 are involved in distinct signal transduction pathways responding to these environmental stresses.

Structural transformation among the aggregate forms of bacteriochlorophyll c as determined by electronic-absorption and NMR spectroscopies: dependence on the stereoisomeric configuration and on the bulkiness of the 8-C side chain

Transformation among the aggregate forms of bacteriochlorophyll (BChl) c characterized by the wavelength of the Qy absorption, i.e. the dimer (B675), B705, B720 and B745, was traced by electronic-absorption spectroscopy for each of the isomers including R[E,E], R[P,E], R[I,E], S[P,E] and S[I,E] suspended in the mixtures of methylene chloride and n-hexane. A combination of NMR spectroscopy determining the structural motifs and calculation of the shift of the Qy absorption reflecting the long-range transition dipole-transition dipole interactions among the macrocycles in the entire aggregate structures proposed the following models: B705d (B705d'), a linear array of straight (inclined) columns consisting of a pair of the piggyback dimers; B720d and B745d, an assembly of two and five shifted-inclined columns consisting of more than six piggyback dimers; and B720m and B745m, an assembly of one and two parallel stepwise stacking of approximately 30 monomers. Calculations of the steric energies rationalized two different pathways of transformations: the dimer-->B705d (B705d')-->B720d-->B745d for the R isomers; and the monomer-->(B720m)-->B745m for the S isomers. Addition of S[I,E] seems to trigger the B745d-->B745m transformation of the R isomers.

cDNA sequence of bovine thioredoxin

In this paper, we report the cDNA sequence of bovine thioredoxin. We determined the full-length cDNA sequence of bovine thioredoxin by RT-PCR, 5'-RACE and 3'-RACE methods. Currently, the thioredoxin cDNA sequences of only five mammalian species (human, macaca, mouse, ovine and rat) are registered in the GenBank database. We performed sequence comparisons on the total cDNA sequence and the coding region, and produced a multialignment between the amino acid sequences of bovine and other mammalian thioredoxins. The amino acid sequences of thioredoxins are highly conserved among mammalian species, for example, only one difference exists between the amino acid sequences of bovine and ovine thioredoxin.

cDNA sequence of bovine thioredoxin

In this paper, we report the cDNA sequence of bovine thioredoxin. We determined the full-length cDNA sequence of bovine thioredoxin by RT-PCR, 5'-RACE and 3'-RACE methods. Currently, the thioredoxin cDNA sequences of only five mammalian species (human, macaca, mouse, ovine and rat) are registered in the GenBank database. We performed sequence comparisons on the total cDNA sequence and the coding region, and produced a multialignment between the amino acid sequences of bovine and other mammalian thioredoxins. The amino acid sequences of thioredoxins are highly conserved among mammalian species, for example, only one difference exists between the amino acid sequences of bovine and ovine thioredoxin.

Surgical effects of combined trabeculotomy and sinusotomy compared to trabeculotomy alone

PURPOSE

To elucidate long-term surgical results and problems of combined trabeculotomy and sinusotomy in comparison with trabeculotomy alone.

METHODS

The study included 91 glaucomatous eyes in 57 patients with primary open angle glaucoma, who underwent either combined trabeculotomy and sinusotomy (40 eyes) or trabeculotomy alone (51 eyes). The mean follow-up period (+/-standard deviation) was 46.1+/-10.4 months (range: 30 to 60 months).

RESULTS

At the final examination, in 37 (93%) of the 40 eyes after combined trabeculotomy and sinusotomy and in 40 (78%) of the 51 eyes after trabeculotomy alone, intraocular pressures were well controlled. The mean intraocular pressures at the end of the first postoperative year were 15.6+/-3.0 mmHg in the 40 eyes after the combined procedure, and 17.8+/-3.1 mmHg in the 51 eyes after trabeculotomy alone (p=0.0001, unpaired t-test). Complications included Descemet's membrane detachment in 1 eye (3%) and 4 eyes (8%), and transient elevation of intraocular pressure to higher than 30 mmHg (IOP spike) in 6 eyes (15%) and 11 eyes (22%), respectively, after the combined procedure and trabeculotomy alone.

CONCLUSION

Combined trabeculotomy and sinusotomy is a useful surgical modality for the treatment of primary open angle glaucoma to obtain lower intraocular pressure levels than those after trabeculotomy alone.

Influence of sulfate-reducing bacteria on outdoor hydrogen production by photosynthetic bacterium with seawater

The application of seawater for bacterial fermentative production is a cost-effective technology. Hydrogen production by marine photosynthetic bacterium with seawater failed to continue after more than 10 days, and was accompanied by the formation of hydrogen sulfide and a change in culture color from red to black. However, substrate consumption in the blackish culture was comparable to that in a hydrogen-producing culture. A decrease in hydrogen production occurred upon the addition of sodium sulfide at concentrations of 1.5 mM or higher. PCR analysis targeted at the 16S rDNA sequence selective for sulfate-reducing bacteria revealed the existence of sulfate-reducing bacteria in inoculation cultures of the phototrophic bacterium and medium for hydrogen production. Hence, the high sulfate concentration of seawater, the low oxidation-reduction potential under hydrogen-producing conditions, and the presence of electron donors such as acetate might promote the metabolic activities of sulfate-reducing bacteria, resulting in the deterioration of hydrogen production with seawater.

Immobilization of ligand-modified polyamidoamine dendrimer for cultivation of hepatoma cells

Cationic polyamidoamine dendrimers are known to be highly branched cascade polymers. The core part of these polymers, tris(2-aminoethyl)amine, was immobilized onto polystyrene plates to which animal cells do not adhere. using photoreactive 4-(3-trifluoromethylazirino) benzoyl-N-succinimide (TDBA-OSu). Cells of a rat hepatoma cell line, H4-II-E-C3, adhered to a surface immobilized with a first-generation dendrimer probably through interactions between the terminal amino groups of the dendrimer and the cell membranes. The adhered cells were viable, could proliferate, and exhibited urea synthetic activity. The modification of the terminal amino groups with fructose increased the final number of cells obtained after 5 days of cultivation. Multigeneration dendrimers were prepared by repeated linkage of tris(2-aminoethyl)amine with the amino groups. Theoretically, the number of terminal amino groups available for ligand modification is twice as much for each generation of dendrimer growth. Cells cultivated on multigeneration fructose-modified dendrimers exhibited enhanced urea synthetic activity. The use of ligand-modified dendrimers is, therefore, considered to be very promising for the construction of bioartificial organs based on cultivation of the animal cells.

MAP kinase cascades in Arabidopsis: their roles in stress and hormone responses

Mitogen-activated protein kinase (MAPK) cascades have essential roles in diverse intracellular signaling processes in plants, animals and yeasts. In plants, MAPK and MAPK-like kinase activities are transiently activated in response to environmental stresses and plant hormones. In addition, transcription of genes encoding protein kinases involved in MAPK cascades in upregulated by environmental stresses. A possible MAPK cascade of Arabidopsis was identified based on both the yeast two-hybrid analysis and functional complementation analysis of yeast mutants. This MAPK cascade may have important roles in stress signal transduction pathways in Arabidopsis.

Increase in thioredoxin activity of intestinal epithelial cells mediated by oxidative stress

Hydrogen peroxide was cytotoxic to the small intestine epithelial cell line, IEC-6, as judged from an MTT assay and the release of lactate dehydrogenase. The glutathione S-transferase and thioredoxin reductase activities and SH content decreased dose-dependently with H2O2, but thioredoxin activity increased at low H2O2 concentrations. In addition, the increase in thioredoxin activity was time-dependent during the initial stages of oxidative stress. A reverse transcription-polymerase chain reaction (RT-PCR) amplification also showed that the mRNA content in IEC-6 cells increased time-dependently at 0.25 mM H2O2. These results indicate that cellular oxidative shock causes an increase in the activity of thioredoxin, which is involved in the defense mechanism against oxidative stress.

Immobilization of tripeptide growth factor glycyl-L-histidyl-L-lysine on poly(vinylalcohol)-quarternized stilbazole (PVA-SbQ) and its use as a ligand for hepatocyte attachment

A tripeptide growth factor, glycyl-L-histidyl-L-lysine (GHK), was immobilized on the surface of poly(vinylalcohol)-quarternized stilbazole (PVA-SbQ) gel. The photoreactive substance, 4-(3-trifluoromethylazirino)benzoyl-N-hydroxysuccinimide (TDBA-OSu), was employed to link the gel and ligand GHK. The density of immobilized GHK was 70 nmol/cm2. Isolated rat hepatocytes were inoculated on the GHK-immobilized PVA-SbQ gel and cultured for 5 d. About 24 h after inoculation, hepatocytes started to aggregate and formed multicellular spheroids while almost no cells attached to GHK-non-immobilized PVA-SbQ gel. The formed spheroids attached firmly to the surface of PVA-SbQ gel for 5 d. GHK was, thus, shown to be an effective ligand for hepatocyte attachment. Dodecamethylenediamine was used to extend the length between the gel surface and GHK. Extension of the length significantly increased the number of attached hepatocytes.

p125 is a novel mammalian Sec23p-interacting protein with structural similarity to phospholipid-modifying proteins

COPII-coated vesicles are involved in protein transport from the endoplasmic reticulum to the Golgi apparatus. COPII consists of three parts: Sar1p and the two protein complexes, Sec23p-Sec24p and Sec13p-Sec31p. Using a glutathione S-transferase fusion protein with mouse Sec23p, we identified a novel mammalian Sec23p-interacting protein, p125, which is clearly distinct from Sec24p. The N-terminal region of p125 is rich in proline residues, and the central and C-terminal regions exhibit significant homology to phospholipid-modifying proteins, especially phosphatidic acid preferring-phospholipase A1. We transiently expressed p125 and mouse Sec23p in mammalian cells and examined their interaction. The results showed that the N-terminal region of p125 is important for the interaction with Sec23p. We confirmed the interaction between the two proteins by a yeast two-hybrid assay. Overexpression of p125, like that of mammalian Sec23p, caused disorganization of the endoplasmic reticulum-Golgi intermediate compartment and Golgi apparatus, suggesting its role in the early secretory pathway.

Intraoperative transesophageal echocardiography for evaluation of mitral valve repair

BACKGROUND AND AIM OF THE STUDY

Although mitral valve repair is a well-established procedure, incorrect assessment of the repaired valve may occasionally lead to the need for reoperation. This study was performed to evaluate the accuracy of color Doppler in assessing the competence of the repaired mitral valve.

METHODS

Transesophageal echocardiography (TEE) and left ventriculography were each performed in 72 patients to compare the two techniques and a semi-quantitative index derived. Using this relationship, post bypass intraoperative TEE was then performed in 34 patients who underwent mitral valve repair, in order to assess the competence of the repaired valve.

RESULTS

Significant differences were apparent in maximal regurgitant mosaic area between angiographic grade 0, and grades 1+ (p = 0.0006), 1+ and 2+ (p < 0.0001) and 2+ and 3+ (p = 0.0010). A maximal regurgitant area < 2 cm2 predicted angiographic grade as 0 (sensitivity 100%, specificity 95%), an area of 2-4 cm2 as 1+ (sensitivity 82%, specificity 100%), an area of 4-7 cm2 as 2+ (sensitivity 78%, specificity 90%), and an area > 7 cm2 as grade 3+ or 4+ (sensitivity 79%, specificity 93%). All 34 patients completed valve repair with the maximal regurgitant mosaic area < 2.5 cm2. Postoperative left ventriculography showed grade +1 in only five patients; four of these completed mitral valve repair with a maximal mosaic area > 2.0 cm2 as assessed by post bypass intraoperative TEE. During follow up, transthoracic echocardiography (TTE) detected recurrent mitral regurgitation which required mitral valve replacement in one patient, and rapid progression of mitral regurgitation in three patients.

CONCLUSIONS

It is important that mitral valve repair should be completed with a maximal mosaic area < 2.0 cm2 as assessed by intraoperative TEE, in order to reduce the need for reoperation.

The structure of an aggregate form of bacteriochlorophyll c showing the Qy absorption at 705 nm as determined by the ring-current effects on 1H and 13C nuclei and by 1H-1H intermolecular NOE correlations

13C-enriched bacteriochlorophyll c (R[E, E] BChl cF) was suspended in chloroform to form an aggregate showing the Qy absorption at 705 nm. (1) The aggregate exhibited several largely split 13C-NMR signals suggesting the presence of non-equivalent BChl c molecules in the form of the piggyback dimer. (2) Changes in the 13C chemical shifts were traced when methanol was titrated to dissolve the aggregate, and the aggregation shifts (in reference to the monomeric state) were determined as a function of the amount of methanol titrated, and they were analyzed empirically. (3) The ring-current effects were calculated based on the loop-current approximation, and the results were compared with the observed aggregation shifts for 13C and 1H nuclei (the 1H aggregation shifts were determined by extrapolation of the data taken from Mizoguchi, T.; Limantara, L.; Matsuura, K.; Shimada, K.; Koyama, Y. J Mol Structure 1996, 379, 249-265). The results showed that the assembly of two straight columns consisting of the piggyback dimer stacked in the antiparallel orientation is the best choice as a model for the B705 aggregate. (4) Three-dimensional F1 13C-edited F3 13C-filtered heteronuclear single-quantum nuclear-Overhauser-effect spectroscopy was applied to the aggregate consisting of a 1:1 mixture of 13C-labeled and unlabeled BChl c in order to selectively detect the intermolecular 1H-1H NOE correlations. The NOE correlations were explained in terms of a straight column, supporting the above model.

Repression of nitrogenase by ethanol in nitrogen-deprived cultures of Rhodovulum sulfidophilum

Light-dependent H2 evolution did not occur in nitrogen-deprived cultures of Rhodovulum sulfidophilum in the presence of ethanol. When ethanol was added to cells which had been grown with ammonia, derepression of the nitrogen fixation genes (nifHD) was inhibited at an ethanol concentration of 1 mM. On the other hand, when cells had nitrogenase-catalyzed proton-reducing activity prior to ethanol addition, reduction of the nifHD transcript level did not occur after the addition. In cells grown with ammonia, concomitant addition of an auxiliary oxidant such as dimethylsulfoxide or sodium bicarbonate resulted in derepression of nitrogenase activity in the presence of ethanol. These results suggest that the electron-accepting process is necessary for derepression of nif genes in cultures which use ethanol as the electron donor.

Effectiveness of polyamidoamine dendrimers modified with tripeptide growth factor, glycyl-l-histidyl-l-lysine, for enhancement of function of hepatoma cells

Cationic polyamidoamine dendrimers are known to be highly branched cascade polymers. Tripeptide growth factor, glycyl-L-histidyl-L-lysine (GHK), was employed as a ligand for activation or attachment of cells from a rat hepatoma cell line, H4-H-E-C3, and immobilized at the terminus of the dendrimer (GHK-dendrimer) to develop a suitable surface for use as a culture substratum in the bioartificial liver support system (BAL). The growth of cells was inhibited by increasing the number of generations of GHK-dendrimers. On the other hand, urea synthesis and lidocaine clearance of the cells adhered on fifth generation GHK-dendrimers were enhanced much more than on first generation GHK-dendrimers. GHK was shown to act as a growth inhibitor and an activator of hepatoma cells. These properties of GHK are advantageous for the utilization of hepatoma cells in BAL. Ligand-modified dendrimers are very promising for the creation of a high-performance substratum for cell culture and high performance bioartificial organs, as well as for high-performance bioartificial liver systems. GHK may have the potential to be a highly useful ligand.

Molecular cloning and characterization of three cDNAs encoding putative mitogen-activated protein kinase kinases (MAPKKs) in Arabidopsis thaliana

We isolated three Arabidopsis thaliana cDNA clones (ATMKK3, ATMKK4 and ATMKK5) encoding protein kinases with extensive homology to the mitogen-activated protein kinase kinases (MAPKKs) of various organisms in the catalytic domain. ATMKK3 shows high homology (85% identity) to NPK2, a tobacco MAPKK homologue. ATMKK4 and 5 are closely related to each other (84% identity). Phylogenetic analysis showed that the plant MAPKKs constitute at least three subgroups. The recombinant ATMKK3 and ATMKK4 were expressed as a fusion protein with glutathione S-transferase (GST) in Escherichia coli. Affinity purified GST-ATMKK3 and GST-ATMKK4 proteins contained phosphorylation activity, which shows that both the ATMKK3 and ATMKK4 genes encode functional protein kinases. Northern blot analysis revealed that the ATMKK3 gene expressed in all the organs. The levels of ATMKK4 and 5 mRNAs were relatively higher in steins and leaves than in flowers and roots. We determined the map positions of the ATMKK3, 4 and 5 genes on Arabidopsis chromosomes by RFLP mapping using P1 genomic clones.

Isolation of ATMEKK1 (a MAP kinase kinase kinase)-interacting proteins and analysis of a MAP kinase cascade in Arabidopsis

In plants, a number of MAP kinase (MAPK), MAPK kinase (MAPKK), and MAPKK kinase (MAPKKK) homologues have been reported. However, there have been no reports of protein-protein interactions between these kinases or molecular analysis of MAPK cascades in higher plants. To analyze a possible MAPK cascade in Arabidopsis thaliana, we took two molecular approaches. One is the two-hybrid screening of ATMEKK1 (a MAPKKK)-interacting proteins; the other is an analysis of physical and functional interactions among isolated MAPK, MAPKK, and MAPKKK homologues from Arabidopsis. In two-hybrid screening using ATMEKK1 as bait, we isolated a novel MAPKK homologue, ATMKK2, a MAPK homologue, ATMPK4, and an unknown protein. ATMKK2 has high sequence similarity with MEK1 (a MAPKK) in Arabidopsis. Based on yeast two-hybrid analysis, we detected protein-protein interactions between ATMEKK1 and ATMKK2/MEK1 (MAPKKs), between ATMKK2/MEK1 and ATMPK4 (a MAPK), and between ATMPK4 and ATMEKK1. ATMPK4 and ATMKK2/MEK1 interacted with two distinct regions of ATMEKK1, the N-terminal regulatory domain and the C-terminal kinase domain, respectively. Coexpression of ATMEKK1 increased the ability of two closely related MAPKKs, ATMKK2 and MEK1, to complement a growth defect of the yeast pbs2 mutant. Coexpression of ATMPK4 and MEK1 complemented a growth defect of the yeast mpk1 and bck1 mutants. By contrast, other combinations of MAPKs and MAPKKs did not suppress these yeast mutations. These results suggest that ATMEKK1, ATMKK2/MEK1, and ATMPK4 may constitute a MAP kinase cascade.

Identification of a possible MAP kinase cascade in Arabidopsis thaliana based on pairwise yeast two-hybrid analysis and functional complementation tests of yeast mutants

A possible MAP kinase (MAPK) cascade of Arabidopsis thaliana was identified on the basis of both yeast 2-hybrid analysis and complementation analysis of yeast mutants. Specific protein-protein interactions between ATMPK4 (a MAPK) and MEK1 (a MAPKK) and interactions between MEK1 and ATMEKK1 (a MAPKKK) were detected by using the 2-hybrid system. A growth defect of the yeast mpk1delta mutant was reversed by coexpression of ATMPK4 and MEK1. Coexpression of the N-terminal deletion form of ATMEKK1 increased the ability of MEK1 to suppress a growth defect of the yeast pbs2delta mutant. These results suggest that ATMPK4, MEK1, and ATMEKK1 may interact with each other and constitute a specific MAPK cascade in Arabidopsis. This is the first demonstration of a possible MAPK cascade in plants.

Intraoperative management for removal of tumor thrombus in the inferior vena cava or the right atrium with multiplane transesophageal echocardiography

BACKGROUND

To investigate the role and impact of multiplane transesophageal echocardiography during thrombectomy in the inferior vena cava or the right atrium.

EXPERIMENTAL DESIGN

Retrospective.

SETTING

A university hospital.

PARTICIPANTS

Four patients who underwent removal of tumor thrombus in the inferior vena cava (IVC) or the right atrium.

INTERVENTIONS

The medical records of 4 patients and videotapes of these intraoperative transesophageal echocardiography examinations were reviewed.

RESULTS

Before thrombectomy, multiplane transesophageal echocardiography (MTEE) provided excellent IVC long axis view, which offered precise recognition of the cephalic extent of tumor, extent of caval occlusion, characterization of the tumor head. During surgery, MTEE could provide continuous monitoring of cardiac function, cardiac volume, and pulmonary embolism. Moreover, MTEE could provide the useful images of a cannula or the caval occlusion balloon catheter, which facilitated removal of neoplasm extending into the IVC.

CONCLUSIONS

We presented four surgical cases, in which the removal of the tumor extended into the inferior vena cava or the right atrium using MTEE. MTEE could provide valuable information such as excellent images of the tumor, cardiac function, the position of a cannula or the caval occlusion balloon catheter. These findings could improve the anesthetic management of the patients, as well as the surgical approach and technical maneuvers, and facilitate removal of neoplasm into the IVC.

Quantitative electroencephalographic correlates of cerebral blood flow in patients with chronic subdural hematomas

BACKGROUND

We have observed that the reduction in cerebral blood flow (CBF) of patients with chronic subdural hematomas is always most pronounced in the thalamus and has a linear correlation with the degree of brain deformity caused by the compression from the hematoma. When the brain is markedly displaced by a hematoma, electroencephalography (EEG) shows delta waves in the frontal region. We theorized that the flow reduction begins in the thalamus, spreading throughout the hemisphere as displacement progresses.

METHODS

We measured CBF using the xenon/computed tomography (CT) method in 10 patients with chronic subdural hematomas who had hemiparesis and/or a mental disturbance and radiographic evidence of a midline shift or herniation. We correlated their flow reductions with topographic encephalograms.

RESULTS

Flow reductions were more pronounced in the thalamus than in the hemisphere and cortex. Slow waves dominated over fast waves, especially in the frontopolar and frontal regions bilaterally. Flow values correlated negatively with the presence of delta and theta waves and positively with that of alpha and beta waves. On the side of the hematoma, the brain wave activity correlated significantly with thalamic flow, and the correlation was greater than with the hemispheric or cortical flow. Thalamic flow correlated more consistently with delta and alpha waves in the central, temporal, and occipital regions, and with beta waves in the frontopolar, frontal, and central regions. On the nonhematoma side, the correlation between brain wave activity and hemispheric flow was significant and greater than with cortical or thalamic flow.

CONCLUSIONS

The correlation of EEGs with thalamic flow, which was maximally reduced, seems to substantiate the concept that the thalamus is primarily injured by brain distortion due to the compression from hematoma and that the remote areas are secondarily deactivated by a transneural depression ("diaschisis") originating from the dysfunctioning thalamus. Thalamic involvement seems to be the cause of the neurologic dysfunction and the abnormal EEG activity in chronic subdural hematomas.

A null lesion in the rhodopin 3,4-desaturase of Rhodospirillum rubrum unmasks a cryptic branch of the carotenoid biosynthetic pathway

The carotenoids accumulated by a mutant Rhodospirillum rubrum ST4, containing a single Tn5 lesion in the pathway for carotenoid biosynthesis, were analyzed by HPLC, 1H NMR spectroscopy, and field desorption mass spectrometry. The main carotenoid was identified as 3,4,3',4'-tetrahydrospirilloxanthin, and the four minor carotenoids were identified as rhodopin, 3,4-dihydroanhydrorhodovibrin, 3', 4'-dihydrorhodovibrin, and 1,1'-dihydroxylycopene. The C-3,4 and C-3',4' bonds of all 5 carotenoids are saturated, and they have 11 conjugated double bonds. With the exception of rhodopin, which is a normal intermediate of the wild-type pathway, all of the carotenoids are not naturally occurring. The Tn5 lesion was assigned to rhodopin 3,4-desaturase which is proposed to catalyze dehydrogenation at both ends of the symmetrical spirilloxanthin derivative. An unexpected finding was that the enzymes following rhodopin 3,4-desaturase are still able to end-modify the 3,4-, and 3',4'-saturated precursors and that the order of methylation and hydroxylation is not obligatory. It is proposed that the observed nonnatural carotenoids can be explained by the inclusion of a cryptic branch, unmasked by the absence of rhodopin 3,4-desaturase, in the established linear pathway for spirilloxanthin biosynthesis. This is the first example of latent branching of the carotenoid biosynthesis pathway exhibited by a carotenoid mutant of a phototrophic bacterium.

Broad spectrum and mode of action of an antibiotic produced by Scytonema sp. TISTR 8208 in a seaweed-type bioreactor

A photobioreactor was constructed using anchored polyurethane foam strips (1 x 1 x 40 cm) fixed onto a stainless-steel ring to prevent flotation, as a biomass support material (BSM). This type of reactor was named a seaweed-type bioreactor. A filamentous cyanobacterium, Scytonema sp. TISTR 8208, which produces a novel cyclic dodecapeptide antibiotic, was immobilized in seaweed-type photobioreactor and cultivated with air containing 5% CO2 sparged at a gas flow rate of 250 mL/min under illumination at a light intensity of 200 mmol photon m-2 s-1. The antibiotic produced in the seaweed-type photobioreactor was purified by HPLC and examined regarding its spectrum and mode of action. The antibiotic effectively inhibited the growth of Gram-positive bacteria, pathogenic yeasts, and filamentous fungi, but it had only a weak effect on Gram-negative bacteria. Scanning electron micrograph analysis showed that the most characteristic change was swelling of the cells after exposure to the antibiotic. The antibiotic seems to alter the conformation of the microbial cell membrane, thereby changing its permeability, leading to osmotic shock.