Cytoplasmic surface structure of bacteriorhodopsin consisting of interhelical loops and C-terminal alpha helix, modified by a variety of environmental factors as studied by (13)C-NMR

We have examined the (13)C-NMR spectra of [3-(13)C] Ala-labeled bacteriorhodopsin and its mutants by varying a variety of environmental or intrinsic factors such as ionic strength, temperature, pH, truncation of the C-terminal alpha helix, and site-directed mutation at cytoplasmic loops, in order to gain insight into a plausible surface structure arising from the C-terminal alpha helix and loops. It is found that the surface structure can be characterized as a complex stabilized by salt bridges or metal-mediated linkages among charged side chains. The surface complex in bacteriorhodopsin is most pronounced under the conditions of 10 mM NaCl at neutral pH but is destabilized to yield relaxed states when environmental factors are changed to high ionic strength, low pH and higher temperature. These two states were readily distinguished by associated spectral changes, including suppressed (cross polarization-magic angle spinning NMR) or displaced (upfield) (13)C signals from the C-terminal alpha helix, or modified spectral features in the loop region. It is also noteworthy that such spectral changes, when going from the complexed to relaxed states, occur either when the C-terminal alpha helix is deleted or site-directed mutations were introduced at a cytoplasmic loop. These observations clearly emphasize that organization of the cytoplasmic surface complex is important in the stabilization of the three-dimensional structure at ambient temperature, and subsequently plays an essential role in biological functions.

Clinical significance of E-cadherin expression in thyroid neoplasms

BACKGROUND AND OBJECTIVE

E-cadherin, a calcium-dependent transmembrane glycoprotein, is an adhesion molecule. We studied clinical significance of E-cadherin expression in thyroid neoplasms.

METHODS

We immunohistochemically studied E-cadherin expression in 60 normal tissue specimens of thyroid tissues and in 82 follicular adenomas, 53 papillary carcinomas, 4 follicular carcinomas, 2 medullary carcinomas, and 5 anaplastic carcinomas of the thyroid.

RESULTS

In papillary carcinoma, E-cadherin expression was preserved significantly less often than in follicular adenoma or normal thyroid tissue (P < 0.01). Preserved E-cadherin expression was seen less often among papillary carcinomas with lymph node metastasis than in those without metastasis (P < 0.05).

CONCLUSIONS

This loss of E-cadherin expression may be involved in regional lymph node metastasis and in malignant potential of thyroid neoplasms. J. Surg. Oncol. 2001;76:176-180.

Annexin II overexpression is correlated with poor prognosis in human gastric carcinoma

Annexins belong to a family of the calcium-dependent phospholipid binding proteins. They are also substrates of receptor tyrosine kinases. Overexpression of Annexin II, which has been reported in various carcinomas, is thought to be associated with cell proliferation, differentiation and cell-cell adhesion in the pathogenesis of carcinoma, but the functions of Annexins have not been fully elucidated. In this study, we investigated the role of Annexin II (p36) and its relationship with c-erbB-2 overexpression in gastric carcinoma. We studied Annexin II expression using Western blot analysis in 8 human gastric carcinoma cell lines and expression of Annexin II and c-erbB-2 using, immunohistochemistry in 153 primary gastric carcinomas. Western blot revealed that Annexin II was expressed in 8 human gastric carcinoma cell lines. It was more strongly expressed in the cell membrane than in the cytoplasm of tumor cells in primary gastric carcinoma tissues. Thirty-three percent of all cases were immunopositive for Annexin II, overexpression of which was more frequent in differentiated type (p = 0.0009), lymph node, metastasis (p = 0.0147) and venous invasion (p = 0.0092). Annexin II and c-erbB-2 overexpression were significantly correlated p = 0.0002) and patients with Annexin II had poorer prognoses (p = 0.0066). Multivariate analysis showed that immunopositivity of both Annexin II and c-erbB-2 was an independent and poor prognostic factor (p = 0.0037). In conclusion, Annexin II was overexpressed in advanced gastric carcinomas and it could contribute to the progression of gastric carcinoma.

Surface dynamics of bacteriorhodopsin as revealed by (13)C NMR studies on [(13)C]Ala-labeled proteins: detection of millisecond or microsecond motions in interhelical loops and C-terminal alpha-helix

We have recorded (13)C NMR spectra of [2-(13)C]-, [1-(13)C]-, [3-(13)C],- and [1,2,3-(13)C(3)]Ala-labeled bacteriorhodopsin (bR), and its mutants, A196G, A160G, and A103C, by means of cross polarization-magic angle spinning (CP-MAS) and dipolar decoupled-magic angle spinning (DD-MAS) techniques, to reveal the conformation and dynamics of bR, with emphasis on the loop and C-terminus structures. The (13)C NMR signals of the loop (C-D, E-F, and F-G) regions were almost completely suppressed from [2-(13)C]-, [1-(13)C]Ala-, and [1-(13)C]Gly-labeled bR, due to the presence of conformational fluctuation with correlation times of 10(-4) s that interfered with the peak-narrowing by magic angle spinning. The observation of such suppressed peaks for specific residues provides a unique means of detecting intermediate frequency motions on the time scale of ms or micros in the surface loops of membrane proteins. Instead, the three well-resolved (13)C CP-MAS NMR signals of [2-(13)C]Ala-bR, at 50.38, 49.90, and 47.96 ppm, were ascribed to the C-terminal alpha-helix previously proposed from the data for [3-(13)C]Ala-bR: the former two peaks were assigned to Ala 232 and 238, in view of the results of successive proteolysis experiments, while the highest-field peak was ascribed to Ala 235 prior to Pro 236. Even such (13)C NMR signals were substantially broadened when (13)C NMR spectra of fully labeled [1,2,3-(13)C]Ala-bR were recorded, because the broadening and splitting of peaks due to the accelerated transverse relaxation rate caused by the increased number of relaxation pathways through a number of (13)C-(13)C homo-nuclear dipolar interactions and scalar J couplings, respectively, are dominant among (13)C-labeled nuclei. In addition, approximate correlation times for local conformational fluctuations of different domains, including the C-terminal tail, C-terminal alpha-helix, loops, and transmembrane alpha-helices, were estimated by measurement of the spin-lattice relaxation times in the laboratory frame and spin-spin relaxation times under the conditions of cross-polarization-magic angle spinning, and comparative study of suppressed specific peaks between the CP-MAS and DD-MAS experiments.

Global effects of anchorage on gene expression during mammary carcinoma cell growth reveal role of tumor necrosis factor-related apoptosis-inducing ligand in anoikis

Anchorage-independent growth is a hallmark of tumor cells. We compared gene expression profiles of anchored and nonanchored human mammary carcinoma cells to study this phenomenon. In this study, we show that anchorage had striking effects on cell growth and morphology but altered transcript levels from a limited number of genes. Only about 1% of mRNA transcripts detected in these cells was altered by anchorage. These include genes related to amino acid and polyamine metabolism, apoptosis, ion channels, cytoskeletal and stress proteins, transcription factors, and growth factors. Some of these may be crucial for the survival of transformed cells. For example, clusterin and the tumor necrosis factor-related apoptosis inducing ligand (TRAIL) were suppressed by anchorage, which could help prevent programmed cell death of these tumor cells. In addition to suppressing TRAIL expression, anchorage also decreased the susceptibility of these tumor cells to TRAIL-induced apoptosis as determined by poly(ADP-ribose) phosphorylase cleavage, annexin-V binding (P < 0.01), and cell cycle analysis (P < 0.0001). These data may help explain mechanisms by which anchorage prevents apoptosis of cells that would otherwise experience anoikis. Thus, genes found to be altered by this analysis could serve as potential targets for anticancer therapy. These findings suggest that TRAIL may be used as a means to target circulating epithelial tumor cells before their attachment and colonization at new sites.

[Appearance of the hepatic artery in Multidetector-row CT using a test bolus injection]

To separate the hepatic artery from the portal vein for the clear appearance of the hepatic artery, we used a test bolus injection in Multidetector-row CT. We examined 25 patients using the following method: 75 ml Iopamidol (370 mgI/ml), at a rate of 5 ml/sec, with scanning commencing 5 sec after the contrast medium reached the upper abdominal aorta. Successful separation could be obtained in almost all of the patients (88%). Separating the hepatic artery from the portal vein enabled us to evaluate the anatomy of the hepatic artery and the abnormality of blood flow in the liver.

A (13)C NMR study on [3-(13)C]-, [1-(13)C]Ala-, or [1-(13)C]Val-labeled transmembrane peptides of bacteriorhodopsin in lipid bilayers: insertion, rigid-body motions, and local conformational fluctuations at ambient temperature

We have recorded (13)C NMR spectra of selectively [3-(13)C]Ala-, [1-(13)C]Ala-, or [1-(13)C]Val-labeled synthetic transmembrane peptides of bacteriorhodopsin (bR) and enzymatically cleaved C-2 fragment in the solid and dimyristoylphosphatidylcholine bilayer. It turned out that these transmembrane peptides either in hexafluoroisopropanol or cast from it take an ordinary alpha-helix (alpha(I)-helix) irrespective of their amino acid sequences with reference to the conformation-dependent (13)C chemical shifts of (Ala)(n) taking the alpha-helix form. These transmembrane peptides are not always static in the lipid bilayer as in the solid state but undergo rigid-body motions with various frequencies as estimated from suppressed peaks either by fast isotropic or large-amplitude motions (>10(8) Hz) or intermediate frequencies (10(5) or 10(3) Hz). Further, (13)C chemical shifts of the [3-(13)C]Ala-labeled peptides in the bilayer were displaced downfield by 0.3-1.1 ppm depending upon amino acid sequence with respect to those in the solid state, which were explained in terms of local conformational fluctuation (10(2) Hz) deviated from the torsion angles (alpha(II)-helix) from those of standard alpha-helix, under anisotropic environment in lipid bilayer, in addition to the above-mentioned rigid-body motions. The carbonyl (13)C peaks, on the other hand, are not sensitively displaced by such local anisotropic fluctuations, because they are more sensitive to the manner of hydrogen-bond interactions. The amino acid sequences of these peptides inserted within the bilayer were not always the same as those of intact bR, causing disposition of the transmembrane alpha-helical segment from that of intact bR. Finally, we confirmed that the (13)C NMR peak positions of the random coil form are located at the boundary between the alpha-helix and a turned structure in loop regions.

Alteration of conformation and dynamics of bacteriorhodopsin induced by protonation of Asp 85 and deprotonation of Schiff base as studied by 13C NMR

According to previous X-ray diffraction studies, the D85N mutant of bacteriorhodopsin (bR) with unprotonated Schiff base assumes a protein conformation similar to that in the M photointermediate. We recorded (13)C NMR spectra of [3-(13)C]Ala- and [1-(13)C]Val-labeled D85N and D85N/D96N mutants at ambient temperature to examine how conformation and dynamics of the protein backbone are altered when the Schiff base is protonated (at pH 7) and unprotonated (at pH 10). Most notably, we found that the peak intensities of three to four [3-(13)C]Ala-labeled residues from the transmembrane alpha-helices, including Ala 39, 51, and 53 (helix B) and 215 (helix G), were suppressed in D85N and D85N/D96N both from CP-MAS (cross polarization-magic angle spinning) and DD-MAS (dipolar decoupled-magic angle spinning) spectra, irrespective of the pH. This is due to conformational change and subsequent acquisition of intermediate time-range motions, with correlation times in the order of 10(-)(5) or 10(-)(4) s, which interferes with proton decoupling frequency or frequency of magic angle spinning, respectively, essential for an attempted peak-narrowing to achieve high-resolution NMR signals. Greater changes were achieved, however, at pH 10, which indicate large-amplitude motions of transmembrane helices upon deprotonation of Schiff base and the formation of the M-like state in the absence of illumination. The spectra detected more rapid motions in the extracellular and/or cytoplasmic loops, with correlation times increasing from 10(-)(4) to 10(-)(5) s. Conformational changes in the transmembrane helices were located at helices B, G, and D as viewed from the above-mentioned spectral changes, as well as at 1-(13)C-labeled Val 49 (helix B), 69 (B-C loop), and [3-(13)C]Ala-labeled Ala 126 (D-helix) signals, in addition to the cytoplasmic and extracellular loops. Further, we found that in the M-like state the charged state of Asp 96 at the cytoplasmic side substantially modulated the conformation and dynamics of the extracellular region through long-distance interaction.

The therapeutic efficacy of VP-343, a selective vasopressin V2 receptor antagonist, in the experimental SIADH rat model

The aim of this work is to investigate the therapeutic efficacy of VP-343 ((N-[4-[[(2S,3aR)-2-hydroxy-2,3,3a,4-tetrahydropyrrolo[1,2-a]qunoxalin-5(1H)-yl]phenyl]-4'-methyl[1,1'-biphenyl]-2-carboxamide), a selective vasopressin V2 receptor antagonist, using the experimental SIADH (syndrome of inappropriate secretion of antidiuretic hormone) rat model. In the model, which was accomplished by administering continuously 1-desamino-8-D-arginine vasopressin (DDAVP), serum sodium levels (S(Na)) and serum osmolarity levels (S(Osm)) significantly and remarkably decreased, which was accompanied with hyper-osmolarity of urine and oliguria. VP-343 increased rapidly and dose-dependently S(Na) and S(Osm). VP-343 exhibited marked diuretic action and decreased urine osmolarity dose-dependently. In the SIADH rat model, all serum levels of chloride, calcium, creatinine, total cholesterol, and uric acid decreased when compared with normal levels. VP-343 increased all serum levels of chloride, calcium, and total cholesterol. These results indicate that VP-343 has efficacy to normalize the abnormalities in DDAVP-induced SIADH.

[Tracing the past half century of my microbial transformation studies]

In the middle of 1950's, microbial transformation technology was introduced into the field of synthetic chemistry as a new methodology. There was a sudden interest in research on the problems of producing steroid hormones by microbial transformation. At that time, the first project entitled "The Study for Microbial Transformation of Steroids", the "Tsuda Project", was established in the Institute of Applied Microbiology (IAM), University of Tokyo, in the spring 1956, in which I took part. This paper summarizes a number of results of our microbial transformation reactions not only in the synthesis of steroidal compounds, but also more broadly for other organic compounds, such as pravastatin, etc. The results are divided into five categories: 1) Microbial transformation of steroids, 2) Correlation between isolation sources of Pseudomonas spp. and their transformation activities, 3) Fermentation Production of prednisolone by Bacillus pulvifaciens SANK 71760, 4) Microbial transformation of siccanin, and 5) Development and fermentation production of pravastatin. About 30 years later, almost at the end of my microbial transformation studies, I had the opportunity to find some microbial strains having superior hydroxylation ability of ML-236BNa to pravastatin. Fortunately, Streptomyces carbophilus SANK 62585 was finally selected as a potent microbial converter with the formation of a lesser amount of by-products. With the view of industrial production of pravastatin, many studies and improvements were made to the culturing conditions to obtain productivity available commercially.

Increased gene expression of components of the renin-angiotensin system in glomeruli of genetically hypertensive rats

OBJECTIVE

The renin-angiotensin system (RAS) is implicated in the development of hypertensive glomerulosclerosis. However, no experimental evidence exists that clearly demonstrates activation of glomerular RAS in hypertensive nephropathy. We used stroke-prone spontaneously hypertensive rats (SHRSP) to examine whether RAS components are increased in glomeruli of SHRSP and whether this increase leads to an increase in mRNA levels for transforming growth factor-beta1 (TGF-beta1).

METHODS

We examined the sequential changes of urinary albumin excretion (UAE), morphology, and glomerular mRNA expression for TGF-beta1 and fibronectin (FN) in relation to glomerular mRNA expression for angiotensinogen (ATN), angiotensin converting enzyme (ACE), angiotensin II type 1a (AT1a), and type 1b (AT1b) receptors, and intervention with angiotensin II type 1 receptor antagonist candesartan and equihypotensive hydralazine.

RESULTS

In SHRSP, UAE was normal at 9 weeks of age, but became higher, beginning at 12 weeks of age, than that in the age-matched Wistar-Kyoto (WKY) rats, while SHRSP showed no glomerulosclerosis until 14 weeks of age; it was marked at 24 weeks. Plasma renin activity and plasma angiotensin II level was equivalent in the 9- and 12-week-old SHRSP and the WKY rats; both parameters, however, were elevated in 24-week-old SHRSP as compared with age-matched control. RNase protection assays showed that glomerular levels of ATN, ACE, and AT1a and AT1b receptors mRNA were significantly increased in 9-, 12-, and 14-week-old, but not in 24-week-old SHRSP, compared with age-matched WKY rats. Northern blot analysis showed that glomerular levels of TGF-beta1 and FN mRNA were higher in SHRSP than in WKY rats at all time points. Candesartan reduced UAE to control levels, whereas hydralazine reduced UAE but not to control levels. Candesartan administration for 12 weeks virtually prevented the progression of glomerulosclerosis. While candesartan reduced mRNA levels for RAS components, TGF-beta1, and FN to control levels, hydralazine was not effective in this respect. Conclusion Results suggest that increases in glomerular RAS components that occur independently of circulating RAS alter glomerular permselectivity and increase the glomerular expression of TGF-beta1 and FN in young SHRSP. Findings in old SHRSP suggest that altered glomerular permselectivity and an increased glomerular expression of TGF-beta1 and FN may be associated with the activation of systemic RAS.

Conformation and backbone dynamics of bacteriorhodopsin revealed by (13)C-NMR

It is demonstrated here how the secondary structure and dynamics of transmembrane helices, as well as surface residues, such as interhelical loops and N- or C-terminus of bacteriorhodopsin (bR) in purple membrane, can be determined at ambient temperature based on very simple (13)C-NMR measurements, together with a brief experimental background. In contrast to the static picture of bR, currently available from X-ray diffraction or cryo-electron microscopy, the structure consists of dynamically heterogeneous domains which undergo various types of local fluctuations with a frequency range of 10(2)--10 (8) Hz. The significance of this picture is discussed in relation to the biological function of this protein.

The larynx during exercise

OBJECTIVES

To develop a system capable of observing the larynx during various body movements and to investigate the relation between upper limb movements and laryngeal closure, often referred as "airtrapping."

STUDY DESIGN

An endoscope capable of observing the larynx during various body movements was developed and the laryngeal state was monitored during these movements in three subjects. The output of 12 subjects' forearms was recorded with and without laryngeal closure.

RESULTS

The larynx was observable even during extreme exercises such as horizontal bar exercises and vault exercises. Laryngeal closure was almost always seen during the beginning of maximum effort of the upper limbs. During constant effort, the state of the larynx varied. When the output of the upper limbs was compared with and without laryngeal closure, there was an average of 20% power loss.

CONCLUSIONS

This study suggests four possible uses for this system. 1) The system could be useful to evaluate laryngeal disorders during exercise such as exercise-induced laryngomalacia. 2) The results could be used to improve the pushing exercise, a voice therapy technique. 3) The status of patients with incomplete laryngeal closure in connection with the upper limbs could be evaluated more thoroughly. 4) The technique and equipment could be used to observe the larynges during normal vocal processes that require body movement.

Conformational transitions and fibrillation mechanism of human calcitonin as studied by high-resolution solid-state 13C NMR

Conformational transitions of human calcitonin (hCT) during fibril formation in the acidic and neutral conditions were investigated by high-resolution solid-state 13C NMR spectroscopy. In aqueous acetic acid solution (pH 3.3), a local alpha-helical form is present around Gly10 whereas a random coil form is dominant as viewed from Phe22, Ala26, and Ala31 in the monomer form on the basis of the 13C chemical shifts. On the other hand, a local beta-sheet form as viewed from Gly10 and Phe22, and both beta-sheet and random coil as viewed from Ala26 and Ala31 were detected in the fibril at pH 3.3. The results indicate that conformational transitions from alpha-helix to beta-sheet, and from random coil to beta-sheet forms occurred in the central and C-terminus regions, respectively, during the fibril formation. The increased 13C resonance intensities of fibrils after a certain delay time suggests that the fibrillation can be explained by a two-step reaction mechanism in which the first step is a homogeneous association to form a nucleus, and the second step is an autocatalytic heterogeneous fibrillation. In contrast to the fibril at pH 3.3, the fibril at pH 7.5 formed a local beta-sheet conformation at the central region and exhibited a random coil at the C-terminus region. Not only a hydrophobic interaction among the amphiphilic alpha-helices, but also an electrostatic interaction between charged side chains can play an important role for the fibril formation at pH 7.5 and 3.3 acting as electrostatically favorable and unfavorable interactions, respectively. These results suggest that hCT fibrils are formed by stacking antiparallel beta-sheets at pH 7.5 and a mixture of antiparallel and parallel beta-sheets at pH 3.3.

Conformation and dynamics of melittin bound to magnetically oriented lipid bilayers by solid-state (31)P and (13)C NMR spectroscopy

The conformation and dynamics of melittin bound to the dimyristoylphosphatidylcholine (DMPC) bilayer and the magnetic orientation in the lipid bilayer systems were investigated by solid-state (31)P and (13)C NMR spectroscopy. Using (31)P NMR, it was found that melittin-lipid bilayers form magnetically oriented elongated vesicles with the long axis parallel to the magnetic field above the liquid crystalline-gel phase transition temperature (T(m) = 24 degrees C). The conformation, orientation, and dynamics of melittin bound to the membrane were further determined by using this magnetically oriented lipid bilayer system. For this purpose, the (13)C NMR spectra of site-specifically (13)C-labeled melittin bound to the membrane in the static, fast magic angle spinning (MAS) and slow MAS conditions were measured. Subsequently, we analyzed the (13)C chemical shift tensors of carbonyl carbons in the peptide backbone under the conditions where they form an alpha-helix and reorient rapidly about the average helical axis. Finally, it was found that melittin adopts a transmembrane alpha-helix whose average axis is parallel to the bilayer normal. The kink angle between the N- and C-terminal helical rods of melittin in the lipid bilayer is approximately 140 degrees or approximately 160 degrees, which is larger than the value of 120 degrees determined by x-ray diffraction studies. Pore formation was clearly observed below the T(m) in the initial stage of lysis by microscope. This is considered to be caused by the association of melittin molecules in the lipid bilayer.

Irreversible conformational change of bacterio-opsin induced by binding of retinal during its reconstitution to bacteriorhodopsin, as studied by (13)C NMR

We compared (13)C NMR spectra of [3-(13)C]Ala- and [1-(13)C]Val-labeled bacterio-opsin (bO), produced either by bleaching bR with hydroxylamine or from a retinal-deficient strain, with those of bacteriorhodopsin (bR), in order to gain insight into the conformational changes of the protein backbone that lead to correct folding after retinal is added to bO. The observed (13)C NMR spectrum of bO produced by bleaching is not greatly different from that of bR, except for the presence of suppressed or decreased peak-intensities. From careful evaluation of the intensity differences between cross polarization magic angle spinning (CP-MAS) and dipolar decoupled-magic angle spinning (DD-MAS) spectra, it appears that the reduced peak-intensities arise from reduced efficiency of cross polarization or interference of internal motions with proton decoupling frequencies. In particular, the E-F and F-G loops and some transmembrane helices of the bleached bO have acquired internal motions whose frequencies interfere with proton decoupling frequencies. In contrast, the protein backbone of the bO from the retinal-negative cells is incompletely folded. Although it contains mainly a-helices, its very broad (13)C NMR signals indicate that its tertiary structure is different from bR. Importantly, this changed structure is identical in form to that of bleached bO from wild-type bR after it was regenerated with retinal in vitro, and bleached with hydroxylamine. We conclude that the binding of retinal is essential for the correct folding of bR after it is inserted in vitro into the lipid bilayer, and the final folded state does not revert to the partially folded form upon removal of the retinal.

Compensatory renal hypertrophy and changes of renal function following nephrectomy

We studied the changes in the serum creatinine level and the volume of the remaining kidney following nephrectomy using contrast-enhanced compounded tomogram (CT) scans. Twenty-five patients undergoing nephrectomy for renal cell carcinoma without obvious disease in the remaining kidney were carefully followed for a period of at least two years at our hospital. Twelve patients received follow-up CT scans each year after nephrectomy. The ellipsoid volume of the kidney was calculated by measuring the 3-dimensional size on CT scans. The mean relative volume (%) of the remaining kidney increased up to year 3 postoperatively, and the final mean relative volume at varying periods from years 2 to 7 was 120%. Kidneys that were smaller prior to nephrectomy showed a tendency to have a larger final relative volume after nephrectomy, although there was no significant correlation between the kidney volume prior to nephrectomy and at final measurement. The mean serum creatinine level was significantly increased at one year after nephrectomy, but it decreased significantly over time. Therefore, both compensatory renal hypertrophy and improved renal function seemed to be established within several years after nephrectomy. However, the improvement of serum creatinine was delayed compared with the increase of kidney volume. That is, renal plasma flow might be increased early by compensatory renal hypertrophy, followed within a few years by an increase in glomerular filtration and a decrease of serum creatinine.

Pharmacological profile of VP-343, a novel selective vasopressin V2 receptor antagonist, in rats

The pharmacological profile of a novel selective vasopressin V2 receptor antagonist, VP-343(N-[4-[[(2S,3aR)-2-hydroxy-2,3,3a,4-tetrahydropyrrolo[ 1,2-a]quinoxalin-5(1H)-yl]carbonyl]phenyl]-4'-methyl[1,1'-biphenyl ]-2-carboxamide) was characterized in several in vitro and in vivo rat models. The IC50 values of VP-343 for vasopressin V1A and V2 receptors were 110 and 0.77 nM, respectively. VP-343 inhibited dose-dependently the pressor response to exogenous arginine vasopressin (AVP; 30 mU/kg, i.v.) in pithed rats, with an ID50 value of 0.57 mg/kg (i.v.). VP-343 induced strong aquaresis in normal saline-loaded conscious rats. Antidiuretic activities of VP-343 have not been detected in AVP deficient Brattleboro rats, showing its lack AVP V2 agonistic activity. During repeated administration for 21 d (3 mg/kg, p.o.) and after recovery, the aquaretic action of VP-343 still remained. In the aged (17 month) saline-loaded conscious rats study, VP-343 (3 mg/kg, p.o.) exhibited remarkable diuretic action. In a single dose oral toxicity study in mice, VP-343 did not produce any clinical signs and mortality at any of the tested doses. The results indicate that VP-343 is a potent, orally active, selective V2 receptor antagonist, suggesting that it can be expected to be useful as an aquaretic drug.

Synovial tissue in rheumatoid arthritis is a source of osteoclast differentiation factor

OBJECTIVE

Osteoclast differentiation factor (ODF; also known as osteoprotegerin ligand, receptor activator of nuclear factor kappaB ligand, and tumor necrosis factor-related activation-induced cytokine) is a recently described cytokine known to be critical in inducing the differentiation of cells of the monocyte/macrophage lineage into osteoclasts. The role of osteoclasts in bone erosion in rheumatoid arthritis (RA) has been demonstrated, but the exact mechanisms involved in the formation and activation of osteoclasts in RA are not known. These studies address the potential role of ODF and the bone and marrow microenvironment in the pathogenesis of osteoclast-mediated bone erosion in RA.

METHODS

Tissue sections from the bone-pannus interface at sites of bone erosion were examined for the presence of osteoclast precursors by the colocalization of messenger RNA (mRNA) for tartrate-resistant acid phosphatase (TRAP) and cathepsin K in mononuclear cells. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to identify mRNA for ODF in synovial tissues, adherent synovial fibroblasts, and activated T lymphocytes derived from patients with RA.

RESULTS

Multinucleated cells expressing both TRAP and cathepsin K mRNA were identified in bone resorption lacunae in areas of pannus invasion into bone in RA patients. In addition, mononuclear cells expressing both TRAP and cathepsin K mRNA (preosteoclasts) were identified in bone marrow in and adjacent to areas of pannus invasion in RA erosions. ODF mRNA was detected by RT-PCR in whole synovial tissues from patients with RA but not in normal synovial tissues. In addition, ODF mRNA was detected in cultured adherent synovial fibroblasts and in activated T lymphocytes derived from RA synovial tissue, which were expanded by exposure to anti-CD3.

CONCLUSION

TRAP-positive, cathepsin K-positive osteoclast precursor cells are identified in areas of pannus invasion into bone in RA. ODF is expressed by both synovial fibroblasts and by activated T lymphocytes derived from synovial tissues from patients with RA. These synovial cells may contribute directly to the expansion of osteoclast precursors and to the formation and activation of osteoclasts at sites of bone erosion in RA.

Doc2alpha is an activity-dependent modulator of excitatory synaptic transmission

Doc2alpha is a synaptic vesicle-associated Ca2 + -binding protein. To study the role of Doc2alpha in synaptic transmission and modulation, we generated homozygous null Doc2alpha mutant mice. In the CA1 region of hippocampal slices in the mutant mice, excitatory synaptic responses evoked with prolonged 5 Hz stimulation showed a significantly larger frequency facilitation followed by a steeper depression than those in wild-type mice, whereas there was no difference in synaptic transmission at lower frequencies or in paired-pulse facilitation. These results suggest that Doc2alpha regulates synaptic transmission when high Ca2 + concentrations in the presynaptic terminal are sustained. Furthermore, the mutant mice showed impairment in long-term potentiation and passive avoidance task. Thus, Doc2alpha may regulate transmitter release during repetitive synaptic activation, thereby contributing to memory formation.

[Roles of outpatient nurses in the care of cancer patients receiving MS Contin tablets]

Pain relief is very important to improve the QOL of cancer patients. Accurate pain assessment and offering suitable drug information on MS Contin tablets (MSC) are important roles of outpatient nurses for the effective use of MSC. We examined the present status of symptom relief among cancer outpatients and from this discuss the practice of outpatient nursing. Forty-eight outpatients receiving MSC were interviewed by mail with regard to pain relief, the side effects of MSC, and the drug information they had been provided. Cancer pain was well controlled in 68% of outpatients by MSC, but MSC was not effective in 13%. Some side effects were observed in 68% of patients, 10% of which were poorly controlled. Sixty-five percent of patients were informed about MSC, but only 47% were informed about measures against these side effects. The following conclusions were reached: 1) MSC should be explained individually and repeatedly, 2) exact informations on a patient's status should be collected using scales and charts, 3) nurse charts should record when MSC is initially administered and when the dosage is changed, and 4) the cases of poorly controlled patients should be studied and specialists consulted if necessary.

How to manage patients with hard-to-recognize postnasal drip?

Postnasal drip (PND), commonly regarded as a phenomenon wherein nasal fluid drips into the pharynx, is one of the main symptoms of chronic sinusitis and other nasal lesions. This definition is controversial, however, because some patients have PND with no evidence of fluid either in the oropharynx or around the choanae. Among 220 patients in whom PND was diagnosed at the University of Tokyo Hospital between January 1996 and December 1997, 19 (8.6%) had hard-to-recognize PND on routine examination. Through careful observation, responsible lesions could be identified in all patients with hard-to-recognize PND. Seven patients had latent chronic sinusitis, 5 had nasopharyngeal lesions, such as Tornwaldt's cyst and inflammation, 3 had "old man's PND", 2 had "reflux PND", and 2 had polyps around the sphenoid ostium. Five patients received no treatment. In the other patients, medical therapy, mainly long-term treatment with low doses of macrolides, now regarded as a standard regimen for intractable chronic sinusitis in Japan, was effective in alleviating symptoms regardless of the cause.

[Cochlear implantation in children with inner ear malformation and postoperative performance]

Cochlear implantation in children with cochlear malformation is on the rise. However, only one case has been reported in Japan. The objective of this paper is to report the authors' experiences with cochlear implants in children with cochlear malformations and, to investigate the morphological classification of cochlear malformation, surgical procedure, complications, and speech perceptions after implantation. Five children (6 ears, including 1 Usher's syndrome and 1 CHARGE association) with congenital inner ear malformations were implanted with multichannel cochlear implants (Nucleus Mini 22 device) between 1994 and 1998. Malformations included common cavity deformity 2, and incomplete partition 4. On the other hand, 4 cases with incomplete partition deformity underwent cochlear implantation by the transmastoid facial recess approach, 2 patients with common cavity deformity received implantation by the transmastoid labyrinthotomy approach. Complications such as facial twitching, cerebrospinal fluid (CSF) gusger, and flap-related problems were encountered. Facial twitching occurred in 1 of 2 patients with common cavity where the electrode array extended into the internal auditory canal. CSF gusher was encountered in 1 of 4 patients with incomplete partition, and revision surgery was performed one week later. One patient had delayed cochlear implant infection and a split pericranial flap was used to cover the defect in the skin flap. Within 6 months, however, the revised pedestal site broke down because of recurrent flap infection. Finally, the cochlear implant was explanted, and the patient underwent a new cochlear implantation in the contralateral ear. All the patients had satisfactory speech reception and word acquisition, but still poor phonetic expression.