Saccharide formation by sustainable formose reaction using heterogeneous zeolite catalysts

The formose reaction is a unique chemical reaction for the preparation of saccharides from formaldehyde, a single carbon compound. We applied zeolite materials as heterogeneous catalysts to the formose reaction. The simple addition of Linde type A zeolite containing calcium ions (Ca-LTA) to an aqueous solution of formaldehyde and glycolaldehyde produced saccharides at room temperature. A quantitative analysis performed by high-performance liquid chromatography revealed that triose, tetrose, pentose, and hexose saccharides were produced with few byproducts. Ca-LTA was recovered from the reaction mixture by filtration, and the retrieved zeolite was found to be reusable under the same conditions. The catalytic activity of Ca-LTA was higher than those of conventional calcium catalysts and other solid materials such as silica, alumina, and hydroxyapatite. Several other types of zeolites with different crystal structures and alkali/alkali-earth metal ions also showed catalytic activity for saccharide formation. Based on the analytical results obtained by infrared spectroscopy, temperature-programmed desorption profiles and NMR measurements, we propose a reaction mechanism in which C-C bond formation is promoted by the mild basicity of the oxygen atoms and acidity on the metal ions of the aluminosilicate on the zeolite surfaces with low SiO2/Al2O3 ratios.

Construction of an autocatalytic reaction cycle in neutral medium for synthesis of life-sustaining sugars

Autocatalytic mechanisms in carbon metabolism, such as the Calvin cycle, are responsible for the biological assimilation of CO2 to form organic compounds with complex structures, including sugars. Compounds that form C-C bonds with CO2 are regenerated in these autocatalytic reaction cycles, and the products are concurrently released. The formose reaction in basic aqueous solution has attracted attention as a nonbiological reaction involving an autocatalytic reaction cycle that non-enzymatically synthesizes sugars from the C1 compound formaldehyde. However, formaldehyde and sugars, which are the substrate and products of the formose reaction, respectively, are consumed in Cannizzaro reactions, particularly under basic aqueous conditions, which makes the formose reaction a fragile sugar-production system. Here, we constructed an autocatalytic reaction cycle for sugar synthesis under neutral conditions. We focused on the weak Brønsted basicity of oxometalate anions such as tungstates and molybdates as catalysts, thereby enabling the aldol reaction, retro-aldol reaction, and aldose-ketose transformation, which collectively constitute the autocatalytic reaction cycle. These bases acted on sugar molecules of substrates together with sodium ions of a Lewis acid to promote deprotonation under neutral conditions, which is the initiation step of the reactions forming an autocatalytic cycle, whereas the Cannizzaro reaction was inhibited. The autocatalytic reaction cycle established using this abiotic approach is a robust sugar production system. Furthermore, we found that the synthesized sugars work as energy storage substances that sustain microbial growth despite their absence in nature.

Molecular recognition of catechol on crystal-like surface of periodic mesoporous organosilica containing pyridinylethynylpyridine

A new periodic mesoporous organosilica (PMO) containing pyridinylethynylpyridine (PEPy) was successfully synthesized under basic conditions in the presence of a cationic surfactant. The PEPy-PMO had a unique mesoporous structure with...

Discovery of Carbono(di)thioates as Indoleamine 2,3-Dioxygenase 1 Inhibitors

A structure-activity relationship study unexpectedly showed that carbonothioates 4a and 4b, obtained by a unique alkaline hydrolysis of 2-alkylthio-oxazolines 3a and 3b, respectively, are a novel scaffold for indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors. Derivatization of the carbonothioates enhanced inhibitory activity against IDO1 and cellular kynurenine production without cytotoxicity and led to the discovery of the related scaffolds carbonodithioates 5 and cyanocarbonimidodithioates 6 as IDO1 inhibitors. Incorporation of an OH group provided the most potent analogue 5i. UV-visible absorption spectroscopy of the Soret band, as well as docking and peptide mapping studies, suggested that these molecules bind to the heme in the active site of IDO1. Our unique IDO1 inhibitors are potential leads for future development.

Heterogeneous water oxidation photocatalysis based on periodic mesoporous organosilica immobilizing a tris(2,2'-bipyridine)ruthenium sensitizer

A periodic mesoporous organosilica (PMO) containing 2,2′-bipyridine groups (BPy-PMO) has been shown to possess a unique pore wall structure in which the 2,2′-bipyridine groups are densely and regularly packed. The surface 2,2′-bipyridine groups can function as chelating ligands for the formation of metal complexes, thus generating molecularly-defined catalytic sites that are exposed on the surface of the material. We here report the construction of a heterogeneous water oxidation photocatalyst by immobilizing several types of tris(2,2′-bipyridine)ruthenium complexes on BPy-PMO where they function as photosensitizers in conjunction with iridium oxide as a catalyst. The Ru complexes produced on BPy-PMO in this work were composed of three bipyridine ligands, including the BPy in the PMO framework and two X₂bpy, denoted herein as Ru(X)-BPy-PMO where X is H (2,2′-bipyridine), Me (4,4′-dimethyl-2,2′-bipyridine), t-Bu(4,4′-di-tert-butyl-2,2′-bipyridine) or CO₂Me (4,4′-dimethoxycarbonyl-2,2′-bipyridine). Efficient photocatalytic water oxidation was achieved by tuning the photochemical properties of the Ru complexes on the BPy-PMO through the incorporation of electron-donating or electron-withdrawing functionalities. The reaction turnover number based on the amount of the Ru complex was improved to 20, which is higher than values previously obtained from PMO systems acting as water oxidation photocatalysts.

Ruthenium complex photosensitizer fixed on 2,2′-bipyridine bridged-periodic mesoporous organosilica with iridium oxide exhibits an efficient photocatalytic water oxidation.

Cooperative Catalysis of an Alcohol Dehydrogenase and Rhodium-Modified Periodic Mesoporous Organosilica

The combined use of a metal-complex catalyst and an enzyme is attractive, but typically results in mutual inactivation. A rhodium (Rh) complex immobilized in a bipyridine-based periodic mesoporous organosilica (BPy-PMO) shows high catalytic activity during transfer hydrogenation, even in the presence of bovine serum albumin (BSA), while a homogeneous Rh complex exhibits reduced activity due to direct interaction with BSA. The use of a smaller protein or an amino acid revealed a clear size-sieving effect of the BPy-PMO that protected the Rh catalyst from direct interactions. A combination of Rh-immobilized BPy-PMO and an enzyme (horse liver alcohol dehydrogenase; HLADH) promoted sequential reactions involving the transfer hydrogenation of NAD⁺ to give NADH followed by the asymmetric hydrogenation of 4-phenyl-2-butanone with high enantioselectivity. The use of BPy-PMO as a support for metal complexes could be applied to other systems consisting of a metal-complex catalyst and an enzyme.

Effects of pore surfaces on the electronic states of metal complexes formed on bipyridine periodic mesoporous organosilica

A combined experimental–theoretical study clarifies correlations between the pore-surface structures and the electronic properties of metal complexes on BPy-PMO.

Transfer hydrogenation of nitrogen heterocycles using a recyclable rhodium catalyst immobilized on bipyridine-periodic mesoporous organosilica

Transfer hydrogenation of unsaturated nitrogen heterocycles using a rhodium catalyst immobilized on bipyridine-periodic mesoporous organosilica (BPy-PMO) is described.

Gemcitabine-based regimen for primary ovarian angiosarcoma with MYC amplification

Angiosarcoma is a rare and aggressive type of sarcoma, and primary angiosarcoma of the ovary is extremely rare. We report the case of a 29-year-old woman who was diagnosed with ovarian angiosarcoma and possible bone metastases. We treated this patient with a gemcitabine-based regimen as postoperative adjuvant chemotherapy, after which she achieved at least 7 years of progression-free survival, an extremely long duration given the aggressive features of this tumour. We retrospectively performed immunohistochemical analyses and fluorescence in situ hybridization to make a pathology diagnosis and to investigate the tumour features. MYC amplification and c-Myc protein overexpression were positively detected. It might be possible to correlate the effectiveness of the gemcitabine-based chemotherapeutic regimen with MYC gene amplification and c-Myc protein overexpression.

Molecular dynamics study-guided identification of cyclic amine structures as novel hydrophobic tail components of hPPARγ agonists

We previously reported that a α-benzylphenylpropanoic acid-type hPPARγ-selective agonist with a piperidine ring as the hydrophobic tail part (3) exhibited sub-micromolar-order hPPARγ agonistic activity. In order to enhance the activity, we planned to carry out structural development based on information obtained from the X-ray crystal structure of hPPARγ ligand binding domain (LBD) complexed with 3. However, the shape and/or nature of the binding pocket surrounding the piperidine ring of 3 could not be precisely delineated because the structure of the omega loop of the LBD was poorly defined. Therefore, we constructed and inserted a plausible omega loop by means of molecular dynamics simulation. We then used the reconstructed LBD structure to design new mono-, bi- and tricyclic amine-bearing compounds that might be expected to show greater binding affinity for the LBD. Here, we describe synthesis and evaluation of α-benzylphenylpropanoic acid derivatives 8. As expected, most of the newly synthesized compounds exhibited more potent hPPARγ agonistic activity and greater hPPARγ binding affinity than 3. Some of these compounds also showed comparable aqueous solubility to 3.

Helix Formation in Synthetic Polymers by Hydrogen Bonding with Native Saccharides in Protic Media

Water-soluble poly(m-ethynylpyridine)s were designed to realize saccharide recognition in protic media. UV/Vis, 1H NMR, and fluorescence measurements revealed that the polymer forms a helical higher order structure by solvophobic interactions between the ethynylpyridine units in the protic medium. The resulting pore in the helix behaves like a binding pocket in proteins, by taking advantage of inwardly directed hydrogen-bonding functional groups of the polymers. Molecular recognition of native saccharides by the polymers was investigated by circular dichroism (CD). The chirality of the saccharide was transferred to the helical sense of the polymers, accompanied by the appearance of induced CDs (ICDs) in the absorptive region of the polymers. In MeOH/water (10/1), mannose and allose showed intense ICDs, and the apparent association constant between the polymer and D-mannose was 14 M(-1).

Regulation of Saccharide Binding with Basic Poly(ethynylpyridine)s by H+-Induced Helix Formation

A basic host polymer exhibiting pH-regulatable saccharide recognition has been investigated. Poly(m-ethynylpyridine) bearing dialkylamino groups forms helical complexes with saccharides to show induced circular dichroism (ICD). When trifluoroacetic acid was titrated on these complexes, the ICD was gradually enhanced until the amount of the acid reached ca. 0.5 molar equivalence versus the pyridine rings in the polymer, and further addition of the acid suppressed the ICD. The proper addition of the acid also increased the binding constants between the polymer and saccharides. These findings would be due to stabilization of the helical structure consisting of cisoid conformations for each of the adjacent pyridine pairs, which were caused by half-protonation of the pyridine rings. Computational analyses indicated that the pyridinium-pyridine dimeric structure prefers its cisoid conformation to its transoid one.

Methane-dependent denitrification by a semi-partitioned reactor supplied separately with methane and oxygen

Methane (CH4) can be used as an alternative carbon source for denitrification with added oxygen (O2). However, the off-gas of denitrification reactors using a CH4-O2 mixture contains unused CH4 and O2 in proportions that make it unusable for fuel, carry explosion risks, and, if released into the atmosphere, contribute to the greenhouse effect. This study tested a novel reactor with a partition dividing the headspace completely and extending partly into the liquid layer. When CH4 and O2 were supplied separately to the liquid layer on opposite sides of the partition, the methane-dependent denitrification (MDD) activity was similar to that when the two gases were supplied as a mixture. In reactors with separate gas supplies, the off-gas from the CH4 supply side was high in CH4 and low in O2, and was usable for fuel, and that from the O2 supply side was very low in CH4, and might be released into the atmosphere. MDD activity increased with the O2 supply rate, and separate discharge of CH4 and O2 was maintained. The concentration of dissolved methane in the effluent was decreased by lowering the CH4/O2 supply ratio to 1.0 and drawing the effluent from the O2 supply side. This novel reactor enhances the safety of MDD, allows reuse of methane as fuel, and reduces methane leakage to the atmosphere.

Microbiological activities contributing to nitrogen removal with methane: effects of methyl fluoride and tungstate

When methane (CH(4)) and O(2) are present, nitrogen can be removed from wastewater that does not contain other organic carbon sources. In this study, microbial activities during methane-dependent denitrification (MDD) were investigated by adding inhibitors of methane-oxidation and denitrification. Sludge susceptible to MDD showed methane oxidation activity in the presence of CH(4) and O(2), and denitrification activity with methanol and acetate under anoxic conditions. Methyl fluoride (CH(3)F) is known to inhibit methane oxidation. When CH(3)F was present, MDD did not occur, perhaps because methane oxidation was inhibited. Tungstate (WO(4)(2-)), a known inhibitor of nitrate reduction, also lowered denitrification activity in the sludge, and partly inhibited methane oxidation. When WO(4)(2-) was added to the medium, MDD almost ceased, perhaps because of a synergic inhibitory effect on denitrification and methane oxidation. These results show that both methane oxidation and denitrification contribute to MDD.

Saccharide-dependent induction of chiral helicity in achiral synthetic hydrogen-bonding oligomers

Conformational transitions of biopolymers are well-known to be affected by noncovalent interactions with small molecules. We found that synthetic polymers, poly- and oligo(meta-ethynylpyridine)s, are guided to helical structures by uncharged hydrogen-bonding interactions with saccharides enclosed in the inner sphere of the polymers. Circular dichroism (CD) studies revealed that chirality of saccharide was transferred to the helical sense of the polymers. Among the n-octyl pyranosides of naturally important hexoses, beta-glucoside induced CDs most effectively. Size-regulated 18-mer and longer oligomers also showed the induced CDs similar to those for the polymers. Furthermore, native monosaccharides were extracted into less polar organic solvent with the help of the polymers, inducing similar CD signals.

Novel synthesis of a tetra-acridinyl peptide as a new DNA polyintercalator

Tetra-acridinyl peptide 2 was synthesized from Fmoc-Lys(Boc)-OH and Fmoc-Lys(Acr)-OH (1) with the peptide synthesizer. The CD measurement suggested that 2 forms a special organized structure by itself in buffered solution. Peptide 2 binds to double stranded DNA with a very large affinity constant, which is 10(3)-times larger than that of quinacrine. Spectrophotometric and hydrodynamic studies suggested that all of the acridinyl parts of 2 contribute to the intercalating interaction for the DNA binding. Our finding in this experiment demonstrates that polyintercalators such as 2 can be assembled quickly by the automated synthesizer.

DNA binding behavior of peptides carrying acridinyl units: First example of effective poly-intercalation

Bis-, tris-, tetrakis-, and pentakis-acridinyl (Acr) peptides 2-5 were synthesized from Fomc-Lys(Acr)-OH and Fmoc-Lys(Boc)-OH with the peptide synthesizer. The molar absorptivity of these peptides saturated with an increase in the number of the acridinyl unit in the peptide, suggesting intramolecular stacking of the acridinyl units. It was found from Scatchard analysis by means of spectrophotometry that all the peptides can bind to double stranded DNA with very high affinity even under high salt conditions (0.4 M NaCl) and the logarithmic binding constant increased in proportion to the number of the acridinyl unit in the peptide. This result suggested effective poly-intercalation of all the acridinyl units into double stranded DNA.

Effects of soy protein diet on the expression of adipose genes and plasma adiponectin

Many studies have reported the cholesterol-lowering, anti-lipogenic, anti-obesity and anti-hypertensive effects of soy protein. Adipose tissue-specific plasma protein, adiponectin, has anti-atherogenic and anti-insulin-resistance properties. Here, we investigated the effects of soy protein diet on body fat composition, plasma glucose, lipid and adiponectin levels and expression of genes involved in glucose and fatty acid metabolism in obese KK-A y mice. Body weights and adipose tissue weights of mesenteric, epididymal, and brown fat were lower in mice on calorie-restricted diet containing soy protein isolate. Plasma cholesterol, triglyceride, free fatty acid, and glucose levels were also decreased by this diet. Body fat content and plasma glucose levels in mice on a soy protein isolate diet were still lower than those treated with an isocaloric casein-protein-diet. Among the genes related to glucose and fatty acid metabolism, adiponectin mRNA levels in adipose tissue and adiponectin plasma concentrations were elevated in mice on a calorie-restricted diet, although there were no significant differences between soy protein and casein protein groups. Our results indicate that that soy protein diet decreased body fat content and plasma glucose levels more effectively than isocaloric casein-protein diet in obese mice.

Effects of nitrite and ammonium on methane-dependent denitrification

For effective application of methane-dependent denitrification (MDD) in the treatment of wastewater containing NO(2)(-) or NH(4)(+), the effect of these inorganic nitrogen compounds on MDD activity needs to be clarified. The MDD activity of sludge acclimatized with CH(4) and O(2) was determined with mineral media of different nitrogen-compound compositions in the presence of 0.21 atm CH(4) and 0.20 atm O(2). Incubations with media containing only NO(2)(-) or two of the three inorganic nitrogen compounds (NO(3)(-)+NO(2)(-), NO(2)(-)+NH(4)(+) or NH(4)(+)+NO(3)(-)) resulted in MDD activity equal to or higher than that with media containing only NO(3)(-). However, there was no MDD activity in media containing NO(2)(-) at 10 degrees C, probably because of serious inhibition of NO(2)(-) on methane oxidation. MDD occurred in media containing only NH(4)(+), although the total nitrogen removal efficiency was very low. These results show that NO(2)(-) and NH(4)(+), in the presence of NO(x)(-), do not inhibit but rather promote MDD. Consequently, NH(4)(+) does not need to be completely oxidized to NO(3)(-) in the nitrification reactor before MDD. However, under psychrophilic conditions, NO(2)(-) seriously inhibited MDD. Therefore, the nitrification reactor must not discharge effluent containing NO(2)(-) under psychrophilic conditions.

Modulation by cAMP of 1alpha,25-dihydroxyvitamin D3 sensitivity of murine erythroleukemia cells

As we previously reported, 1alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3) dose-dependently inhibited not only proliferation of undifferentiated murine erythroleukemia (MEL) cells but also activin A-induced erythroid differentiation of MEL cells. However, the effect of 1,25(OH)2D3 on MEL cell proliferation was significantly greater by one order of magnitude than that on differentiation (IC(50): 9.2 vs 0.8 nM, respectively). The response of activin A-treated mature MEL cells to 1,25(OH)2D3 in the induction of 1,25(OH)2D3-24-hydroxylase (24-OHase) activity, a rapid effect of 1,25(OH)2D3, was enhanced to the same degree as in untreated immature cells, suggesting that differences in capacity of cells to inactivate 1,25(OH)2D3 did not contribute to augmentation of 1,25(OH)2D3 effect in activin A-treated mature cells. Furthermore, neither the number nor the affinity of vitamin D receptors (VDR) differed significantly between activin A-treated cells and untreated immature cells. The intracellular cAMP level, which affects 1,25(OH)2D3-mediated induction of 24-OHase activity, was significantly less in activin A-treated mature cells than in immature MEL cells. The addition of dibutyryl cAMP (dbc AMP) to activin A-treated MEL cells dose-dependently attenuated 1,25(OH)2D3-mediated induction of 24-OHase activity, finally to a level comparable to that of the untreated cells at the final concentration of 100 nM dbcAMP, while dbcAMP itself by 100 nM did not affect MEL cell differentiation by 24 h. In summary, we have shown for the first time that 1,25(OH)2D3 exerted its effect on leukemia cells at physiological concentration and that the magnitude of this effect depended on the changes in intracellular cAMP level through stages of differentiation, suggesting that the cAMP-protein kinase A system may be useful as a target for clinical application of vitamin D analogs by improving the sensitivity of leukemic cells to 1,25(OH)2D3.

Involvement of oxygen free radicals in experimental retinal ischemia and the selective vulnerability of retinal damage

Protective effects of CV-3611, a free radical scavenger, on retinal ischemic injury in the rat and on glutamate-induced cytotoxicity in a cell line were evaluated. Transient retinal ischemia was induced by raising intraocular pressure of rats to 110 mm Hg for 45 min, and the electroretinogram (ERG) was measured to evaluate retinal function. No ERG could be recorded immediately after reperfusion, and thereafter the ERG gradually recovered. Recovery of the a-wave latency and the amplitudes of the a and b waves in the CV-3611-treated (10 mg/kg, p.o.) group were significantly better than those in the control group up to 24 h after reperfusion. In both the control and CV-3611 group, the b wave showed better recovery than the a wave up to 6 h after reperfusion, while the relationship was reversed after 24-hour reperfusion. Glutamate (10 mM)-induced cytotoxicity in the N18-RE-105 cell, a neural retina-neuroblastoma hybridoma, was quantified by measuring lactate dehydrogenase. Three and 10 microM of CV-3611 significantly attenuated the glutamate-induced cytotoxicity in N18-RE-105 cells. Thus, the radical scavenger (CV-3611) promoted the recovery of retinal function after ischemia-reperfusion injury and ameliorated glutamate-induced cytotoxicity. These results suggest that oxygen free radicals play an important role in the early phase of retinal ischemic injury. Moreover, differential recovery processes of the a and b waves after ischemia suggest that the selective vulnerability of the retina to ischemia could change functionally during the period of reperfusion.

Reduction of intraocular pressure by topical administration of an inhibitor of the Rho-associated protein kinase

PURPOSE

Rho-associated coiled coil-forming protein kinase (ROCK) is a downstream target of a small GTPase, Rho. The kinase has been reported to regulate actomyosin-based contractility of smooth muscles by modulation of myosin phosphatase activity. Contractility of ciliary muscle could be implicated in regulation of intraocular pressure while that of ocular vessels could affect blood flow to retina. The present study has been performed to investigate the effect of a ROCK inhibitor on intraocular pressure in rabbits.

METHODS

An inhibitor of ROCK, Y-27632, was dissolved in an ophthalmic solution and topically administered to the eye of a Japanese white rabbit. Intraocular pressure was measured by pneumatonography (n = 12, 24 eyes). Constriction of ciliary muscle was measured by the Magnus method using 12 eyes.

RESULTS

Topical application of 0.1 and 0.03% Y-27632 significantly decreased the intraocular pressure, with maximum decreases of 5.3 and 4.3 mm Hg after 90 minutes compared with the control eye. Y-27632 inhibited the carbachol-induced constriction of rabbit ciliary muscle.

CONCLUSIONS

The ROCK inhibitor reduced intraocular pressure in rabbits by topical instillation. The inhibitor relaxed the excised ciliary muscle which was previously constricted by carbachol suggesting that the inhibitor acts to increase the uveoscleral outflow. Our results suggest that the ROCK inhibitor is a promising treatment for glaucoma therapy in the next generation.

Effect of topically applied iganidipine dihydrochloride, a novel calcium antagonist, on optic nerve head circulation in rabbits

PURPOSE

To study the effect of topically applied iganidipine dihydrochloride (iganidipine), a novel water-soluble calcium channel blocker, on blood flow in the optic nerve head (ONH), intraocular pressure, and systemic blood pressure in rabbits.

METHODS

After 0.1% iganidipine (20 microL) was instilled into normal eyes, the change in ONH blood flow was measured using a hydrogen gas clearance flowmeter. Iganidipine (0.0001% to 0.1%) was instilled into eyes with impaired ocular circulation before or after the intravitreal injection of endothelin-1, and the change in ONH blood flow was measured. Changes in intraocular pressure and blood pressure after instillation of 0.1% iganidipine were measured. In all experiments, physiological saline was instilled into the contralateral eye as a control.

RESULTS

Iganidipine significantly increased the ONH blood flow in normal eyes with the maximum increment of 31.7% at 45 minutes after instillation. Preinstillation of 0.01% and 0.1% iganidipine significantly inhibited the decrease in ONH blood flow in the eyes with impaired circulation. Moreover, ONH blood flow recovered with postinstillation of 0.1% iganidipine. These effects were persistent. Instillation of 0.1% iganidipine did not change either the intraocular pressure or the blood pressure.

CONCLUSION

The instillation of iganidipine persistently increased and maintained the ONH blood flow in rabbit eyes with normal and impaired ocular circulation.

Effect of Topically Applied Iganidipine Dihydrochloride, a Novel Ca(2+) Antagonist, on Optic Nerve Head Circulation in Rabbits

Purpose: We studied the effect of topically applied iganidipine dihydrochloride, a novel water-soluble calcium channel blocker on the blood flow of optic nerve head (ONH), intraocular pressure, and blood pressure in rabbits.Methods: (1) 0.1% iganidipine (20 &mgr;l) was instilled into a normal eye. The change in blood flow in the ONH was measured using a hydrogen gas clearance flowmeter. (2) Iganidipine (0.0001%-0.1%) was instilled into a circulation-disordered eye before or after the intravitreal injection of endothelin-1, and change in the blood flow in the ONH was measured. (3) Changes in intraocular pressure and blood pressure after instillation of 0.1% iganidipine were measured. In all experiments, physiological saline was instilled in each contralateral eye as a control.Results: (1) Instillation of iganidipine significantly increased the blood flow in the ONH by 40% at 45 minutes after instillation. (2) Pre-instillation of 0.01 and 0.1% iganidipine almost completely inhibited the decrease of blood flow in the ONH in the circulation-disordered model. The decrease of blood flow in the ONH was corrected with post-instillation of 0.1% iganidipine. These effects were continuous. (3) Instillation of 0.1% iganidipine did not change either intraocular pressure or blood pressure.Conclusion: It was shown that instillation of iganidipine continuously increased and maintained the blood flow in the ONH in normal and circulation-disordered rabbit eye models.

[Homogenous low-density lipoprotein assay in type III hyperlipoproteinemia]

To investigate whether homogenous analysis of serum low-density lipoprotein cholesterol(LDL-C) was applicable in type III hyperlipoproteinemic subjects, 3 reagents were used to estimate LDL-C in 2 cases with apoE 2/2 phenotype. Each measurements were compared to LDL-C levels by ultracentrifugation(density: 1.019-1.063). LDL-C levels by homogenous analysis with any of the reagents were higher than those by ultracentrifugation, and the difference was varied between the reagents: +14-24% by LDL-EX, +29-55% by Cholestest LDL, and +89-115% by Determiner LDL-C. The cross-reaction by the reagents to intermediate density lipoprotein(IDL) and very low density lipoprotein(VLDL) cholesterol was studied in a case; 22% of cholesterol in these fractions was measured by LDL-EX, 32% by Cholestest LDL, and 110% by Determiner LDL-C. A part of the sample serum was stored at -60 degrees C for several days and melted for re-analysis of homogenous LDL-C levels. After the freezing process, IDL fraction pattern on electrophoresis had been changed and homogenous LDL-C levels by all reagents were different from the measurements of native serum. These results indicated that using reagents with low cross-reaction to IDL and VLDL fractions and careful sample handling are important in homogenous LDL-C analysis in type III hyperlipoproteinemia.

[Effect of topically applied iganidipine dihydrochloride, a novel Ca2+ antagonist, on optic nerve head circulation in rabbits]

PURPOSE

We studied the effect of topically applied iganidipine dihydrochloride, a novel water-soluble calcium channel blocker on the blood flow of optic nerve head (ONH), intraocular pressure, and blood pressure in rabbits.

METHODS

1. 0.1% iganidipine (20 microliters) was instilled into a normal eye. The change in blood flow in the ONH was measured using a hydrogen gas clearance flowmeter. 2. Iganidipine (0.0001%-0.1%) was instilled into a circulation-disordered eye before or after the intravitreal injection of endothelin-1, and change in the blood flow in the ONH was measured. 3. Changes in intraocular pressure and blood pressure after instillation of 0.1% iganidipine were measured. In all experiments, physiological saline was instilled in each contralateral eye as a control.

RESULTS

1. Instillation of iganidipine significantly increased the blood flow in the ONH by 40% at 45 minutes after instillation. 2. Pre-instillation of 0.01 and 0.1% iganidipine almost completely inhibited the decrease of blood flow in the ONH in the circulation-disordered model. The decrease of blood flow in the ONH was corrected with post-instillation of 0.1% iganidipine. These effects were continuous. 3. Instillation of 0.1% iganidipine did not change either intraocular pressure or blood pressure.

CONCLUSION

It was shown that instillation of iganidipine continuously increased and maintained the blood flow in the ONH in normal and circulation-disordered rabbit eye models.

HUGE: a database for human large proteins identified in the Kazusa cDNA sequencing project

HUGE is a database for human large proteins newly identified in the Kazusa cDNA project, the aim of which is to predict the primary structure of proteins from the sequences of human large cDNAs (>4 kb). In particular, cDNA clones capable of coding for large proteins (>50 kDa) are the current targets of the project. HUGE contains >1100 cDNA sequences and detailed information obtained through analysis of the sequences of cDNAs and the predicted proteins. Besides an increase in the number of cDNA entries, the amount of experimental data for expression profiling has been largely increased and data on chromosomal locations have been newly added. All of the protein-coding regions were examined by GeneMark analysis, and the results of a motif/domain search of each predicted protein sequence against the Pfam database have been newly added. HUGE is available through the WWW at http://www.kazusa.or.jp/huge

Inhibitory mechanism of the CXCR4 antagonist T22 against human immunodeficiency virus type 1 infection

We recently reported that a cationic peptide, T22 ([Tyr(5,12), Lys(7)]-polyphemusin II), specifically inhibits human immunodeficiency virus type 1 (HIV-1) infection mediated by CXCR4 (T. Murakami et al., J. Exp. Med. 186:1389-1393, 1997). Here we demonstrate that T22 effectively inhibits replication of T-tropic HIV-1, including primary isolates, but not of non-T-tropic strains. By using a panel of chimeric viruses between T- and M-tropic HIV-1 strains, viral determinants for T22 susceptibility were mapped to the V3 loop region of gp120. T22 bound to CXCR4 and interfered with stromal-cell-derived factor-1alpha-CXCR4 interactions in a competitive manner. Blocking of anti-CXCR4 monoclonal antibodies by T22 suggested that the peptide interacts with the N terminus and two of the extracellular loops of CXCR4. Furthermore, the inhibition of cell-cell fusion in cells expressing CXCR4/CXCR2 chimeric receptors suggested that determinants for sensitivity of CXCR4 to T22 include the three extracellular loops of the coreceptor.

High-level production of alternatively spliced soluble interleukin-6 receptor in serum of patients with adult T-cell leukaemia/HTLV-I-associated myelopathy

We have previously shown, using human T-cell lymphocytotrophic virus-I (HTLV-I)-infected cell lines, that soluble interleukin-6 receptor (sIL-6R) is generated through an alternative splicing mechanism. In this study, we examined human sera for the presence of alternatively spliced soluble IL-6R (AS-sIL-6R). We produced a monoclonal antibody (mAb) recognizing the unique sequence of AS-sIL-6R peptide, generated by an altered reading frame. We also made recombinant AS-sIL-6R protein in Spodoptera frugiperda-9 (Sf-9) cells carrying baculovirus, which encoded altered sIL-6R or conventional IL-6R cDNA. mAbs specifically recognized AS-sIL-6R, but not conventional IL-6R, as demonstrated by Western blot analyses, fluorescence-activated cell sorter, immunofluorescence analyses and enzyme-linked immunosorbent assay (ELISA). We adapted an ELISA system and used it for detection of altered sIL-6R in sera from 23 healthy persons, 12 patients with adult T-cell leukaemia (ATL) and 13 patients with HTLV-I-associated myelopathy (HAM). Serum levels of AS-sIL-6R were 6.4 or 6.1 times greater in ATL (28.7+/-20.4 ng/ml, P<0.0001) and in HAM patients (27.5+/-12.1 ng/ml, P<0.0001) than in healthy individuals (4.5+/-2.1 ng/ml). High levels of AS-sIL-6R were also observed in plasma from rheumatoid arthritis patients and in persons with elevated levels of alanine aminotransferase (ALT), antinuclear antibody (ANA), or alpha-fetoprotein (AFP). However, in human immunodeficiency virus-1 (HIV-1), hepatitis B virus (HBV) or hepatitis C virus (HCV)-infected individuals, AS-sIL-6R levels were not elevated. In this study, we confirmed that AS-sIL-6R is indeed present in human sera. These observations suggest that alternative splicing of IL-6R mRNA is of consequence in ATL, HAM and in some autoimmune diseases. The HTLV-I-infected T cells appeared to play an important role in AS-sIL-6R production.

Pharmacophore identification of a chemokine receptor (CXCR4) antagonist, T22 ([Tyr(5,12),Lys7]-polyphemusin II), which specifically blocks T cell-line-tropic HIV-1 infection

We have previously found that T22 ([Tyr(5,12), Lys7]-polyphemusin II) has strong anti-human immunodeficiency virus (HIV) activity, and that T22 inhibits T cell-line-tropic HIV-1 infection mediated by CXCR4/fusin. T22 is an 18-residue peptide amide, which takes an antiparallel beta-sheet structure that is maintained by two disulfide bridges. Structure-activity relationship (SAR) studies on T22 have disclosed the contributions of each region of T22 to activity or cytotoxicity, and have provided the following useful information to develop new CXCR4 antagonists: The number of Arg residues in the N-terminal and C-terminal regions of T22 is closely related to anti-HIV activity. Addition of a variety of functional groups at the N-terminal end results in increases in activity. Disulfide rings, especially the major disulfide loop, are indispensable for anti-HIV activity and maintenance of the beta-sheet structure. Trp3 can be replaced by other aromatic residues (Tyr, Phe and L-2-naphthylalanine). Between two repeats of Tyr-Arg-Lys, which are a characteristic structure in T22, Tyr-Arg-Lys in the N-terminal portion is more closely associated with anti-HIV activity and maintenance of the beta-sheet structure. A positive charge in the side chain at the (i + 1) position of the beta-turn region is necessary for strong activity. Through these studies, we have found several compounds having higher selectivity indexes (50% cytotoxic concentration/50% effective concentration) than that of T22.