Intensity of the polarized Raman band at 1340-1345 cm-1 as an indicator of protein alpha-helix orientation: application to Pf1 filamentous virus

Raman spectra of oriented alpha-helical protein molecules exhibit a prominent band near 1340-1345 cm(-)(1), the intensity of which is highly sensitive to molecular orientation. Polarization of the 1340-1345 cm(-)(1) marker is evident in Raman spectra of alpha-helical poly-L-alanine (alphaPLA) and alpha-helical poly-gamma-benzyl-L-glutamate (alphaPBLG). Corresponding polarization is also observed in Raman spectra of the filamentous virus Pf1, which is an assembly of alpha-helical coat protein molecules. In alphaPLA and alphaPBLG, we assign the band to a normal mode of symmetry type E(2) and specifically to a vibration localized in the (O=C)-C(alpha)-H linkages of the main chain peptide group. Although strict helical symmetry does not apply to coat subunits of filamentous viruses, an approximate E(2)-type mode may be presumed to account for a corresponding Raman band of Pf1 and fd filamentous viruses. Spectroscopic studies of N-methylacetamide and isotopically-edited fd viruses support the present assignment of the 1340-1345 cm(-)(1) band. Polarization anisotropy indicates that this band may be exploited as a novel indicator of protein alpha-helix orientation. Application of this approach to the polarized Raman spectrum of Pf1 suggests that, on average, the axis of the alpha-helical coat protein subunit in the native virion structure forms an angle of 20 +/- 10 degrees with respect to the virion axis.

A Na+/Ca2+ exchanger inhibitor, KB-R7943, caused negative inotropic responses and negative followed by positive chronotropic responses in isolated, blood-perfused dog heart preparations

Effects of a Na+/Ca2+ exchanger inhibitor, KB-R7943 (2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl] isothiourea methanesulfonate), on the sinoatrial nodal pacemaker activity, atrial contractility and ventricular contractility were investigated in the isolated and blood-perfused right atrium and left ventricle of the dog. KB-R7943 (0.03- 3 micromol) induced negative inotropic effects and negative followed by positive chronotropic effects in the right atrium and negative inotropic effects in the left ventricle. Neither atropine nor hexamethonium affected the cardiac responses to KB-R7943. Propranolol attenuated the positive chronotropic response to KB-R7943 but imipramine did not. Tetrodotoxin potentiated the positive chronotropic response to KB-R7943 in 6 of 11 isolated atria. When NaCl infusion increased atrial contractile force and atrial rate, KB-R7943-induced negative inotropic and chronotropic responses were attenuated in a dose-dependent manner. CaCl2 infusion potentiated the negative chronotropic response to KB-R7943 but did not affect the inotropic response significantly. On the other hand, ouabain (17 nmol) attenuated the negative inotropic response, but not chronotropic response, to KB-R7943. These results suggest that KB-R7943-induced cardiac effects relate to the Na+ activity, probably mediated through the Na+/Ca2+ exchanger, and the Na+/Ca2+ exchanger modifies the pacemaker activity and myocardial contractility in the dog heart.

Effects of phosphorus-containing calcium preparation (bone meal powder) and calcium carbonate on serum calcium and phosphorus in young and old healthy volunteers: a double-blinded crossover study

To evaluate the effects of bone meal powder (BEC) on calcium and phosphorus metabolism, a calcium absorption test was conducted using a preparation of calcium carbonate (CAC) as the control drug. A total of 12 healthy volunteers, consisting of 6 younger (aged 20-29 years, 3 men and 3 women) and 6 older (aged 60-69 years, 3 men and 3 women) persons, were subjected to a double-blinded crossover study. Serum calcium (s-Ca) level significantly increased to 105.3% +/- 1.9% (P < 0.01 vs the basal value; mean +/- SD) from the basal value in the BEC group and to 104.4% +/- 2.7% (P < 0.01) in the CAC group at 3h post load. Urinary excretions of calcium (u-Ca/glomerular filtration rate, u-Ca/GF) after BEC and CAC load rose to 226.6% +/- 154.5% (P < 0.05) and 211.1% +/- 148.0% (P < 0.05), respectively. Serum phosphorus (s-P) levels after BEC load increased to 110.0% +/- 15.1% (P < 0.05), whereas that after CAC load showed no significant change (99.3% +/- 7.9%). On the other hand, urinary excretion of phosphorus (u-P/GF) after CAC load decreased to 60.0% +/- 32.4% (P < 0.01) and that in the BEC group showed no significant change (92.5% +/- 49.5%). The increase in s-Ca led to decrease in serum intact parathyroid hormone (i-PTH) level [77.3% +/- 33.4% (P < 0.05) for BEC and 69.5% +/- 20.3% (P < 0.01) for CAC] although s-P was increased by the BEC load. The responses to BEC and CAC administration were compared in the younger and the older groups. The responses in the younger and the older group showed fundamentally the same trends and to the same extent. However, the changes in serum ionized calcium (i-Ca) and i-PTH levels at 1.5 h post load were significantly smaller in the older group than in the younger group (P < 0.01; P < 0.05). The increment in s-P level after BEC load in the older group was larger than that in the younger group. In conclusion, BEC can modulate not only calcium but also phosphorus metabolism in both younger and older subjects. Further investigations are required to evaluate the effects of BEC on bone density and safety for renal function in long-term observations.

Inhibition of caspase cascade by HTLV-I tax through induction of NF-kappaB nuclear translocation

NF-kappaB is required for prevention of apoptosis. We examined the importance of human T-cell leukemia virus-I (HTLV-I) Tax protein to stimulate NF-kappaB nuclear translocation, thus preventing apoptosis. Jurkat cells and JPX-9 cells in which the inducible Tax expression plasmid vector was stably transfected were used in the present study. Both Jurkat and Tax(-) JPX-9 cells had small amounts of basal nuclear NF-kappaB activity. The addition of NF-kappaB inhibitors suppressed NF-kappaB nuclear translocation of the cells, thus inducing apoptosis. Sequential activation of caspases from caspase-8 to caspase-3 was shown during this process. NF-kappaB nuclear translocation in JPX-9 cells was stimulated through Tax expression, and both the activation of caspases and apoptosis induced by NF-kappaB inhibitors were significantly suppressed in the Tax(+) JPX-9 cells. The expression of Bcl-2, Bax, and Bcl-x was not changed among Jurkat, Tax(-) JPX-9, and Tax(+) JPX-9 cells in the presence or absence of NF-kappaB inhibitors. X-chromosome-linked inhibitor of apoptosis (XIAP) protein expression in Tax(-) JPX-9 cells was significantly suppressed by NF-kappaB inhibitors, however, its expression in Tax(+) JPX-9 cells was maintained even by the addition of NF-kappaB inhibitors. Our results suggest that the activation of NF-kappaB via Tax protein in HTLV-I infected cells renders the cells resistant to apoptosis. The expression of anti-apoptotic gene products such as XIAP to suppress caspase cascade, results in an increase of cytokine production and cell proliferation; one of the proposed mechanisms that promotes autoimmune disorders such as Sjögren's syndrome and rheumatoid arthritis found in HTLV-I seropositive subjects.

[A case of ectopic pituitary adenoma localized in the sphenoid sinus]

Intrasphenoidal pituitary adenoma is relatively rare. Only 13 cases have been reported in the literature. We present a case of intrasphenoidal pituitary adenoma in a 74-year-old man. He had no endocrinological abnormalities. Skull tomograms revealed sellar floor erosion but showed no enlargement of the pituitary fossa. Computed tomographic (CT) scan revealed an isodense mass showing no contrast enhancement in the sphenoid sinus. The intrasphenoidal tumor appeared slightly hypointense compared with normal brain on T1-weighted image, and showed less contrast enhancement after intravenous injection of Gd-DTPA on magnetic resonance imaging (MRI). Transsphenoidal pituitary microsurgery was performed, and all of the intrasphenoidal tumor was removed with the mucosa. The sellar floor was thin and easily breakable in parts. After removal of the sellar floor the dura was opened, but no evidence of a pituitary tumor was shown. No connection between the pituitary gland and the sphenoidal tissue was found. Microscopic examination of sections showed tumor cell nests in the sphenoidal mucosa. We think this ectopic pituitary adenoma occurred through the migration of Rathke's pouch in the sphenoid sinus.

How and how much can Hoechst 33258 cause unwinding in a DNA duplex?

The effect of Hoechst 33258 binding on the geometry of a DNA duplex (plasmid pBR322) has been examined using topoisomerase II relaxation followed by gel electrophoresis. Of this drug-DNA system, fluorescence, optical absorption, and calorimetric measurements were also made at various drug and DNA concentrations and in the same buffer as that for the topoisomerase reaction. It has been confirmed that there are two modes of drug-DNA interaction. When the drug concentration is much lower than the DNA base pair concentration, the Hoechst 33258 molecule binds in the minor groove of the DNA duplex and occupies a site formed of five continuous base pair sequences that contain no G.C pair. Here, the equilibrium constant K1 is 1.8 x 10(7) M-1 (at 37 degrees C), and the enthalpy of binding delta H1 is -865 cal/mol. When the drug concentration is much higher, on the other hand, it shows another binding mode which is much weaker, so that K2 = 2.25 x 10(4) M-1 and delta H2 is -464 cal/mol, which gives fluorescence quenching, which has no base pair preference, and which causes an unwinding of the duplex by 1 degree.

Tumor necrosis factor-alpha and interleukin-1beta increase the Fas-mediated apoptosis of human osteoblasts

Our recent work demonstrated functional Fas expression on human osteoblasts, and the histologic examination of the periarticular osteoporosis region in patients with rheumatoid arthritis (RA) showed apoptosis in osteoblasts. High concentrations of interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), and IL-6--which are thought to increase bone resorption--have been determined in RA synovium. We investigated the effect of these cytokines on the Fas-mediated apoptosis of human osteoblasts. The human osteoblastic cell line MG63 and human primary osteoblast-like cells from bone biopsy specimens were used as human osteoblasts. Fas expression on these cells was examined by flow cytometry, and Fas-mediated apoptosis induced by anti-Fas immunoglobulin M (IgM) was determined by a chromium 51 release assay, the presence of cells with hypodiploid DNA, staining with Hoechst 33258 dye, and the detection of DNA fragmentation on agarose gel electrophoresis. The proliferation of osteoblasts was analyzed by a tritiated thymidine incorporation assay. Spontaneous apoptosis was not found on cultured osteoblasts. The apoptosis of human osteoblasts was not induced by TNF-alpha, IL-1beta, or IL-6 alone in the absence of anti-Fas IgM. In addition, proliferation of the cells was not affected by these cytokines. Fas was constitutively expressed on unstimulated osteoblasts, and treatment of these cells with IL-1beta or TNF-alpha significantly augmented Fas expression. Human osteoblasts were committed to apoptosis with anti-Fas IgM, and the treatment of both IL-1beta and TNF-alpha markedly increased Fas-mediated apoptosis. TNF-alpha augmented both Fas expression and Fas-mediated apoptosis more efficiently than did IL-1beta. In addition, an additive effect on both Fas expression and Fas-mediated apoptosis was demonstrated when TNF-alpha and IL-1beta were added to osteoblasts. IL-6 influenced neither Fas expression nor the Fas-mediated apoptosis of osteoblasts. Furthermore, no synergistic effect of IL-6 with IL-1beta or TNF-alpha was observed. IL-1beta, TNF-alpha, or IL-6 did not change Bcl-2 expression. Our results suggest that IL-1beta and TNF-alpha regulate osteoblast cell number by up-regulating the Fas-mediated apoptosis of osteoblasts, one of the putative mechanisms inducing periarticular osteoporosis in patients with RA.

Inhibitory effect of a new anti-rheumatic drug T-614 on costimulatory molecule expression, cytokine production, and antigen presentation by synovial cells

The present study was undertaken to investigate the immunoregulatory effects of T-614 (3-formylamino-7-methylsulfonylamino-6-phenoxy-4H-1-benzopyran-4-o ne) on synovial cells in vitro. Synovial cells were cultured with T-614 in the presence or absence of various cytokines. After incubation, the costimulatory molecule expression on synovial cells and cytokine production in culture supernatants were analyzed by an indirect immunofluorescence method and enzyme-linked immunosorbent assay, respectively. We also examined the effect of T-614 on the function of synovial cells as antigen-presenting cells (APCs). The costimulatory molecules including CD54, CD58, and CD106 were constitutionally expressed on the surface of synovial cells. However, neither CD80 nor CD86 nor CD102 was found on the surface, and these costimulatory molecules could not be induced by any cytokines. T-614 itself did not affect the costimulatory molecule expression and cytokine production of unstimulated synovial cells. The stimulation of synovial cells with interferon-gamma (IFN-gamma), interleukin-1beta, or 12-O-tetradecanoyl phorbol 13-acetate enhanced the expression of costimulatory molecules and the proinflammatory cytokine production of these cells. Both the up-regulated expression of these costimulatory molecules and the enhanced production of proinflammatory cytokines were significantly inhibited by T-614. Autologous T cell proliferation in response to purified protein derivative by IFN-gamma-treated synovial cells was significantly suppressed by T-614. T-614 has considerable immunosuppressive effects on synovial cells by inhibiting the costimulatory molecule expression and cytokine production of these cells and the antigen-specific T cell proliferation mediated by the synovial cells. These results suggest that T-614 plays an important immunoregulatory role in rheumatoid synovial tissues.

Construction of an effective host-vector system for the yeast Saccharomyces exiguus Yp74L-3

An effective host-vector system specific to the yeast Saccharomyces exiguus Yp74L-3 was constructed to promote the molecular genetic analyses for the yeast. To obtain a stable reversionless host strain, we constructed an S. exiguus strain carrying leu2::ScURA3 by disrupting the S. exiguus LEU2 gene with the S. cerevisiae URA3 gene. A vector plasmid unique to S. exiguus was subsequently developed by inserting both the LEU2 gene and an ARS cloned from S. exiguus into an Escherichia coli phagemid, pUC119. The vector constructed, pTH119 was able to transform the S. exiguus leu2::ScURA3 strain to Leu+ efficiently. The stability of the vector in the S. exiguus host cells resembled that of a YRp-type vector in S. cerevisiae.

Effects of amlodipine on native cardiac Na+ channels and cloned alpha-subunits of cardiac Na+ channels

The inhibitory effects of amlodipine besilate (CAS 11470-99-6) on the native Na+ current (INa) and cloned human cardiac Na+ channel alpha subunit (hH1) were studied by whole cell patch clamp techniques. Amlodipine produced tonic block of INa in a concentration- and holding potential (HP)-dependent manner with hyperpolarization of H infinity. Amlodipine produced phasic blockade of INa, which was dependent on HP and pulse duration. Amlodipine produced tonic blockade of hH1 in a concentration-dependent manner with 1 : 1 stoichiometry, and phasic blockade of hH1 which was dependent on the pulse duration. Amlodipine blocked INa in a voltage- and frequency-dependent manner via affinity to the resting as well as inactivated conformations of the alpha subunit.

Polarizing microscopy of eyespot of Chlamydomonas: in situ observation of its location, orientation, and multiplication

The eyespot in the cell of Chlamydomonas reinhardtii has been found to appear as a bright spot under the cross polar setting of a polarizing microscope. This was confirmed by isolating the eyespot from a homogenate of wall-deficient mutant cw-15, and by observing it under a polarizing microscope. Thus, the eyespot was proved to be a strongly birefringent body. Next, gametes (mt+ and mt-) of 137c strain were prepared by cultivating it in a low-nitrogen (NH4Cl) medium. Here, every cell shows only one (and never more than one) birefringent spot. The birefringent eyespot was located always near the surface on the "equator," that is, at the farthest point from the "meridionial" cell-axis that is defined as the bisector of the two flagella projected out from the cell surface. It was shown, in addition, that the optic axis of this birefringent eyespot is oriented in the cell always along the parallel direction of the cell axis defined above. Thus, the polarizing microscopy has been shown to provide a powerful method for in vivo, in situ pursuit of the eyespot of Chlamydomonas.

Successful treatment of adult-onset Henoch-Schönlein purpura nephritis with high-dose immunoglobulins

A 26-year-old woman was admitted for the evaluation of edema and massive proteinuria. She had a history of purpura of the lower extremities, abdominal pain and melena. Laboratory investigations showed hypoalbuminemia, hypercholesterolemia and proteinuria of over 10 g/day. Renal biopsy showed moderate proliferative glomerulonephritis with mesangial immunoglobulin A (IgA) deposition. She was diagnosed as having Henoch-Schonlein purpura nephritis. Oral prednisolone, dipyridamole and intravenous heparin treatment were not effective. Steroid pulse therapy induced a partial improvement of proteinuria to 2-3 g/day. High-dose intravenous immunoglobulin (i.v.-IG) treatment was introduced and a dramatic improvement of proteinuria was noted. I.v.-IG should be fully considered in patients with steroid-resistant Henoch-Schonlein purpura nephritis.

The autonomously replicating sequence (ARS) of the yeast Saccharomyces exiguus Yp74L-3

Fragments containing ARSes were cloned from the genomic DNA of the yeast Saccharomyces exiguus Yp74L-3, and the essential regions for ARSes were restricted for these fragments. Mapping studies of ARS-acting sequences in one of these fragments suggested that S. exiguus recognizes a sequence as an ARS that is different from that recognized by Saccharomyces cerevisiae. Two ARS essential regions of S. exiguus were sequenced, and an ARS core consensus sequence of S. exiguus was deduced to be MATTAMWAWWTK. This sequence differs significantly from that of S. cerevisiae in two positions, suggesting that these nucleotide substitutions cause the difference in the ARS-recognition modes between S. exiguus and S. cerevisiae.

DNA sequence of the β-isopropylmalate dehydrogenase gene and phylogenetic analysis of the yeast Saccharomyces exiguus Yp74L-3

The beta-isopropylmalate dehydrogenase (LEU2) gene from a homothallic wild-type yeast, Saccharomyces exiguus Yp74L-3, was analyzed to estimate the phylogenetic position of this strain in yeasts. The beta-isopropylmalate dehydrogenase gene of Yp74L-3 was first isolated as a clone complementing the leu2 mutation of Saccharomyces cerevisiae, and then confirmed to complement the haploid leu2 mutant derived from strain Yp74L-3 through genetic transformation. The nucleotide sequence of the cloned DNA revealed an open reading frame (ORF) encoding the beta-isopropylmalate dehydrogenase composed of 365 amino acids. The beta-isopropylmalate dehydrogenase coding sequence from the Yp74L-3 strain displayed 76.7% similarity to that of S. cerevisiae. Candidates for a UAS and a TATA-box in the 5'-upstream region and for a poly-A attachment site in the 3'-downstream region were found. A phylogenetic tree constructed from the nucleotide sequences of the beta-isopropylmalate dehydrogenase coding regions revealed that Yp74L-3 is located between S. cerevisiae and the Kluyveromyces yeasts. The LEU2 gene cloned from Yp74L-3 will serve as an effective genetic marker for constructing the transformation system in S. exiguus Yp74L-3.

A short region from the LEU2 gene of Saccharomyces cerevisiae functions as an ARS in the yeast Saccharomyces exiguus Yp74L-3

We examined the autonomously replicating sequence (ARS) activity of some fragments derived from the LEU2 region of Saccharomyces cerevisiae onto Saccharomyces exiguus Yp74L-3. A DNA fragment functioning as an ARS in S. exiguus, but not in S. cerevisiae, was shown to exist. The ARS activity for S. exiguus was reduced by the 2-microm plasmid origin of S. cerevisiae when both elements coexisted on a single circular plasmid. Analysis of ARS activity with the PCR products from the fragment revealed that the ARS-acting sequence was located in the 3'-terminal area of the transcribed region of the LEU2 gene of S. cerevisiae. It is suggested that the ARS recognition system in S. exiguus is significantly different from that of S. cerevisiae.

Differences in the electrophysiological response to I- and the inhibitory anions SCN- and ClO-4, studied in FRTL-5 cells

The electrophysiological properties of the Na+/I- symporter (NIS) were examined in a cloned rat thyroid cell line (FRTL-5) using the whole-cell patch-clamp technique. When the holding potential was between -40 mV and -80 mV, 1 mM NaI and NaSCN induced an immediate inward current which was greater with SCN- than with I-. The reversal potential for I- and SCN- induced membrane currents was +50 mV. This is close to the value of +55 mV calculated by the Nernst equation for Na+. These results are consistent with I- and SCN- translocation via the NIS that is energized by the electrochemical gradient of Na+ and coupled to the transport of two or more Na+. There was no change in the membrane current recording with ClO-4 indicating that ClO-4 was either not transported into the cell, or the translocation was electroneutral. ClO-4 addition, however, did reverse the inward currents induced by I- or SCN-. These effects of I-, SCN- and ClO-4 on membrane currents reflect endogenous NIS activity since the responses duplicated those seen in CHO cells transfected with NIS. There were additional currents elicited by SCN- in FRTL-5 cells under certain conditions. For example at holding potentials of 0 and +30 mV, 1 mM SCN- produced an increasingly greater outward current. This outward current was transient. In addition, when SCN- was washed off the cells a transient inward current was detected. Unlike SCN-, 1-10 mM I- had no observable effect on the membrane current at holding potentials of 0 and +30 mV. The results indicate FRTL-5 cells may have a specific SCN- translocation system in addition to the SCN- translocation by the I- porter. Differences demonstrated in current response may explain some of the complicated influx and efflux properties of I-, SCN- and ClO-4 in thyroid cells.

Identification of the orotidine-5'-phosphate decarboxylase gene and development of a transformation system in the yeast Saccharomyces exiguus Yp74L-3

To investigate the uracil biosynthetic pathway of the yeast Saccharomyces exiguus Yp74L-3, uracil auxotrophic mutants were isolated. Using conventional genetic techniques, four mutant genes concerned in uracil biosynthesis were identified and denoted as ura1, ura2, ura3, and ura4. Mutations in the URA3 and URA4 genes were specifically selected with 5-fluoroorotic acid (5-FOA). Vector plasmids containing the URA3 gene and an autonomously replicating sequence (ARS) of S. cerevisiae produced sufficient amounts of Ura+ transformants from the ura4 mutant of S. exiguus. This fact indicates that the S. exiguus URA4 gene encodes orotidine-5'-phosphate decarboxylase (OMP decarboxylase) and demonstrates that vector plasmids for S. cerevisiae are also usable in S. exiguus.

Expression and function of Fas and Fas ligand on peripheral blood lymphocytes in normal subjects

We investigated the expression and function of Fas and Fas ligand (FasL) on peripheral blood lymphocytes (PBLs). The cells were stimulated with various cytokines or 12-0-tetradecanoyl phorbol 13-acetate (PMA) plus ionomycin. About 30% of unstimulated PBLs expressed Fas, and the expression was augmented by interleukin-1beta (IL-1beta), IL-2, tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), or PMA plus ionomycin. Although only minimal FasL expression was detected on unstimulated PBLs, FasL expression was markedly induced by IL-2 or PMA plus ionomycin, suggesting that Fas and FasL were both expressed on IL-2-stimulated or PMA-plus-ionomycin-stimulated PBLs. Although IL-2-stimulated or PMA-plus-ionomycin-stimulated PBLs were positive for both Fas and FasL, no significant increase in apoptosis was demonstrated in these activated PBLs. In addition, treatment of PBLs with IL-2 or PMA plus ionomycin did not change anti-Fas-induced apoptosis, although these activated PBLs expressed Fas strongly when compared with unstimulated PBLs. Only IL-2-stimulated or PMA-plus-ionomycin-stimulated PBLs killed Fas+ target cells efficiently via the interaction of Fas on target cells with FasL of PBLs. Bcl-2 was constitutively expressed on unstimulated PBLs, but its expression was significantly augmented by IL-2 or PMA plus ionomycin. The expression of Bax was clearly induced only on IL-2-stimulated or PMA-plus-ionomycin-stimulated PBLs and that of other Bcl-2 family proteins such as Bcl-x and Bad could not be detected on human PBLs, including IL-2-stimulated or PMA-plus-ionomycin-stimulated PBLs. Our results suggest that PBLs activated by IL-2 or PMA plus ionomycin express both Fas and FasL and that they kill Fas+ target cells by using FasL on the surface. The resistance of these activated PBLs to Fas-mediated apoptosis may be due to the augmented Bcl-2 expression or the presence of Bcl-2:Bax heterodimers on these cells.

The average unwinding angle of DNA duplex produced by the binding of chromomycin A3

The effect of chromomycin A3 binding on the geometry of DNA duplex (plasmid pBR322) has been examined using topoisomerase I relaxation followed by gel electrophoresis. To determine the equilibrium constant of this drug-DNA binding-dissociation reaction in the same concentration range (ca. 10(-5) M) in the same buffer as those for the topoisomerase reaction (at 37 degrees C), fluorescence measurements were made of the same plasmid-drug system, followed by a Scatchard plot and an analysis using McGhee-von Hippel's exclusion site model. The binding constant has been found to be 3.8 x 10(5) M-1 in the particular buffer (buffer-T) at 37 degrees C, and the number of base pairs involved in the site of one chromomycin molecule on the duplex has been found to be 5. It has been concluded that one chromomycin molecule, bound to the duplex, unwinds it by 11.8 +/- 1.1 degrees. In addition, the enthalpy of binding was determined to be 31.81 kJ/mole using a titration calorimeter with a more concentrated (6.2 mM) solution.

Effect of sulfhydryl oxidoreduction on permeability of cardiac tetrodotoxin-insensitive sodium channel

Effects of sulfhydryl oxidizing and reducing agents on permeability of the tetrodotoxin (TTX)-insensitive Na-channel were investigated in guinea-pig ventricular myocytes using the whole-cell patch-clamp technique. Mercury chloride (HgCl2) at 1-100 microM irreversibly blocked Na+ currents with no significant changes in the gating kinetics. In contrast, the hydrophilic sulfhydryl oxidizing agent, thimerosal at 50-100 microM little affected Na+ permeation through the Na-channel. The Hg2+-induced block of Na+ current could be readily reversed by 1,4-dithiothreitol (DTT), an agent that reduces disulfide bonds. These results indicate that the formation of sulfur-Hg-sulfur bridge is essential for Hg2+ block. Pretreatment with DTT prevented the Hg2+ block of Na+ current, whereas Zn2+ and Cd2+ retained their abilities to block Na+ current after DTT treatment. An application of Zn2+ or Cd2+ resulted in the restoration of Hg2+ sensitivity of the DTT-treated channel. A conformational model for the Na-channel with multiple free sulfhydryl groups and native disulfide bonds could account for our experimental data regarding the effects of sulfhydryl modifying agents on the channel permeability. We conclude that the cardiac TTX-insensitive Na-channel contains functionally important free sulfhydryl groups and disulfide bonds which are accessible from the extracellular side by an aqueous pathway. These sulfhydryls would be capable of modulating the Na-channel permeability by affecting the conformation of channel pore region.

Excess urate excretion correlates with severely acidic urine in patients with renal hypouricemia

We evaluated the renal handling of urate in 12 Japanese renal hypouricemia patients, and studied the relationship between the renal handling of urate and the urinary pH. The patients were classified into the 4 subtypes of renal hypouricemia: (defective presecretory reabsorption (Pre), defective postsecretory reabsorption (Post), enhanced tubular secretion (Secretion), and defective presecretory and postsecretory reabsorption (Pre&Post) as based on a pharmacological test. Seven patients showed acid urine with a urinary pH of less than 5.9, although this was not accompanied by any abnormality of blood pH, partial pressure of carbon dioxide (PaCO2), or blood HCO3-. The urinary pH in the morning significantly correlated with the ratio of urate clearance to creatinine clearance in the morning, whereas the urinary urate concentration in the morning did not correlate with the urinary pH in the morning. In the Pre&Post patients, the urate excretion was higher and the urinary pH was more acidic compared to the other subtypes. The administration of K+-, Na+-citrate significantly alkalized the urinary pH in the patients with renal hypouricemia. These results suggest that the acidic urine was significantly related to the Pre&Post subtype of renal hypouricemia with the higher urate excretion, and that this subtype might be a risk factor for complications in renal hypouricemia. The alkalization of urine might be a useful treatment for the complication of renal hypouricemia.

CD4+ T-cell-mediated cytotoxicity against staphylococcal enterotoxin B-pulsed synovial cells

Apoptosis of synovial cells in rheumatoid arthritis (RA) synovium determined in vivo is suggested to counteract the overgrowth of synovium. Immunohistological examination has revealed the infiltration of activated CD4+ T cells, which express Fas ligand (FasL), in RA synovium. The presence of a putative antigen (Ag) of autoimmune disorders in a target organ may induce the activation of specific T cells in the inflammatory region such as RA synovium. We examined the possible role of CD4+ T cells activated by synovial cells in a staphylococcal enterotoxin B (SEB)-dependent manner, inducing synovial cell apoptosis. Synovial cells were cultured with or without interferon-gamma (IFN-gamma) and further incubated with CD4+ T cells in the presence of SEB. After the cocultivation, both the cytotoxicity and FasL expression of CD4+ T cells were investigated. Constitutive Fas expression was detected on both unstimulated and IFN-gamma-stimulated synovial cells. CD4+ T cells did not kill SEB-pulsed unstimulated synovial cells efficiently. In contrast, when CD4+ T cells were incubated with IFN-gamma-stimulated synovial cells with SEB whose human leucocyte antigen (HLA)-DR and -DQ expression was markedly induced, significant cytotoxicity by these cells against synovial cells was detected. The addition of anti-HLA-DR and -DQ monoclonal antibodies (mAbs) or human Fas chimeric protein (hFas-Fc) reduced this cytotoxicity. FasL expression of CD4+ T cells cocultured with IFN-gamma-stimulated synovial cells with SEB was significantly induced. Furthermore, the addition of mAbs against CD54, CD58 and CD106 inhibited both the cytotoxicity and FasL expression of CD4+ T cells induced by IFN-gamma-stimulated synovial cells in the presence of SEB, indicating the importance of costimulatory molecules on synovial cells in activating CD4+ T cells. Our results suggest that CD4+ T cells are activated by synovial cells by an SEB-dependent manner and express FasL, inducing Fas-mediated apoptosis of the latter cells. These phenomena may regulate the overgrowth of synovial cells in RA synovium.

CNP causes receptor-mediated positive dromotropic effects in anesthetized dog hearts

No data are available for the direct effect of C-type natriuretic peptide (CNP) on atrioventricular (AV) conduction in mammalian hearts. Thus we studied the dromotropic effects of CNP-22 injected into the AV node artery in autonomically decentralized hearts in open-chest, anesthetized dogs. CNP decreased AV interval (AV conduction time) in a dose-dependent manner with increase in coronary artery blood flow rate in six anesthetized dogs. Isosorbide dinitrate did not affect AV interval, but it increased coronary artery blood flow rate. A guanylyl cyclase-linked natriuretic peptide receptor antagonist, HS-142-1, inhibited the decreases in AV interval and the increases in coronary blood flow rate in response to CNP, whereas propranolol did not affect the positive dromotropic response to CNP. These results demonstrate that CNP decreases AV interval and increases coronary artery blood flow rate mediated by a guanylyl cyclase-linked natriuretic peptide receptor, but not beta-adrenoceptor, in the dog heart.

Synthesis and pharmacological activities of 13-dehydro derivatives of primary prostaglandins

13-Dehydro derivatives of prostaglandin E1, E2, E3, F1 alpha and F2 alpha were synthesized. Compared with natural prostaglandins, 13-dehydro analogues were found to exhibit more potent inhibitory activity against human platelet aggregation and relaxation of guinea-pig isolated trachea, while they showed less potent activity of contraction of guinea-pig isolated ileum.

Increased Fas-mediated cytotoxicity of CD4-positive T cells in patients with human T-lymphotropic virus type I-associated myelopathy

Using a 51Cr release assay, we investigated Fas-mediated cytotoxicity of peripheral blood CD4+ T cells of patients with human T-lymphotropic virus type-I (HTLV-I)-associated myelopathy (HAM) against T98G, a glioblastoma cell line which expresses Fas. Cytotoxic activity of CD4+ T cells against T98G was significantly higher in HAM patients than in controls. Moreover, when CD4+ T cells of HAM patients were preincubated with a monoclonal antibody to human Fas ligand (FasL), cytotoxic activity against T98G was significantly suppressed. These results suggest that damage to nervous tissues by the Fas/FasL system is involved in the pathogenesis of HAM.

Insulin-like growth factor I stimulates proliferation and Fas-mediated apoptosis of human osteoblasts

In vitro studies have shown that insulin-like growth factor I (IGF-I) is a potent growth factor for osteoblasts, although both bone formation and resorption are upregulated by IGF-I in vivo. To understand the difference in the action of IGF-I observed in vitro and in vivo experiments, we examined the effect of IGF-I on the proliferation and Fas-mediated apoptosis of human osteoblasts in vitro. Human osteoblastic cell line MG63 and human primary osteoblast-like cells obtained from biopsy specimens were used as human osteoblasts. Cells were cultured with or without various concentrations of IGF-I followed by determination of the proliferative response and Fas-mediated apoptosis. IGF-I dose dependently stimulated the proliferation of cultured human osteoblasts. Both Fas expression and the degree of anti-Fas IgM-induced apoptosis of human osteoblasts was also augmented by IGF-I. Furthermore, the cytotoxicity of Fas ligand (FasL) cDNA transformants against human osteoblasts was increased when IGF-I-stimulated osteoblasts were used as target cells, indicating that stimulation of IGF-I increased functional Fas expression on human osteoblasts as well as their proliferation. The addition of DEVD-CHO, a specific inhibitor of CPP32, to the culture resulted in a significant inhibition of Fas-mediated apoptosis of both unstimulated and IGF-I-stimulated osteoblasts, although it did not affect the proliferative response or Fas expression. Our data suggest that activation of CPP32 is necessary for Fas-mediated apoptosis of human osteoblasts, and treatment of IGF-I increased this signaling pathway. In contrast, regulation of proliferation and Fas expression of the cells were probably not affected by CPP32 activation. Our results suggest that IGF-I acts on cultured human osteoblasts by increasing their proliferation and induction of Fas-mediated apoptosis by neighbouring FasL+ cells such as osteoclasts, thus probably functioning as a local coupling factor in the bone in vivo, stimulating both bone formation and resorption.

Raman scattering tensors of adenine

Polarized Raman scattering measurements have been made of a single crystal of adenine dihydrochloride (adenine-2H+) by the use of Raman microscope with 488.0 nm excitation. The adenine-2H+ crystal belongs to the space group Pnma (orthorhombic), and Raman intensities of Iaa, Ibb, Icc and Iac (which correspond to the aa, bb, cc and ac components of the crystal Raman tensor) have been determined for each Raman band. The depolarization ratios of Raman bands have been observed for fully random molecular orientations in an adenine 6N HCl aqueous solution. From these experimental data, and by taking the known crystal structure into account, anisotropic and isotropic molecular Raman scattering tensors have been determined for each vibrational mode of the adenine residue.

Raman scattering tensors of tyrosine

Polarized Raman scattering measurements have been made of a single crystal of L-tyrosine by the use of a Raman microscope with the 488.0-nm exciting beam from an argon ion laser. The L-tyrosine crystal belongs to the space group P2(1)2(1)2(1) (orthorhombic), and Raman scattering intensities corresponding to the aa, bb, cc, ab and ac components of the crystal Raman tensor have been determined for each prominent Raman band. A similar set of measurements has been made of L-tyrosine-d4, in which four hydrogen atoms on the benzene ring are replaced by deuterium atoms. The effects of NH3-->ND3 and OH-->OD on the Raman spectrum have also been examined. In addition, depolarization ratios of some bands of L-tyrosine in aqueous solutions of pH 13 and pH 1 were examined. For comparison with these experimental results, on the other hand, ab initio molecular orbital calculations have been made of the normal modes of vibration and their associated polarizability oscillations of the L-tyrosine molecule. On the basis of these experimental data and by referring to the results of the calculations, discussions have been presented on the Raman tensors associated to some Raman bands, including those at 829 cm-1 (benzene ring breathing), 642 cm-1 (benzene ring deformation), and 432 cm-1 (C alpha-C beta-C gamma bending).

Inhibitory effect of glucocorticoid for osteoblast apoptosis induced by activated peripheral blood mononuclear cells

Recent studies suggest a protective effect of glucocorticoid against progression of bone erosion and periarticular osteoporosis in patients with rheumatoid arthritis (RA), although this steroid hormone itself is believed to increase bone loss. To understand the antagonistic effect of glucocorticoid for osteopenic process in RA patients, we examined the effect of dexamethasone on Fas-mediated apoptosis of cultured human osteoblasts induced by either anti-Fas IgM or activated peripheral blood mononuclear cells (PBMC). Human osteoblastic cell line MG63 and primary osteoblast-like cells obtained from biopsy specimens were used in this study. PBMC isolated from healthy donors were cultured with or without recombinant interleukin-2 (rIL-2) followed by 12-O-tetradecanoyl-phorbol 13-acetate (PMA) with ionomycin in the presence or absence of dexamethasone. Fas was functionally expressed on MG63 and primary osteoblast-like cells, and treatment of these cells with dexamethasone affected neither Fas expression nor anti-Fas IgM-induced apoptosis. Activated PBMC expressing membrane-type Fas ligand (mFasL) efficiently killed both MG63 and primary osteoblasts-like cells, and the addition of human Fas chimeric protein (hFas-Fc) significantly diminished the cytotoxicity, indicating that interactions between mFasL of activated PBMC and Fas on human osteoblasts induce apoptosis of the latter. Although dexamethasone did not affect apoptosis of MG63 and primary osteoblast-like cells induced by anti-Fas IgM, treatment of activated PBMC with dexamethasone markedly inhibited both mFasL expression and cytotoxicity of these cells against human osteoblasts, suggesting that dexamethasone preferentially acts not on osteoblasts but PBMC. Cultured supernatants from activated PBMC induced apoptosis of human osteoblasts and the addition of hFas-Fc also inhibited the cytotoxicity of the supernatants. In addition, soluble form FasL (sFasL) was detected in the supernatants of activated PBMC. Furthermore, both the cytotoxicity and sFasL concentration of cultured supernatants of activated PBMC incubated with dexamethasone was significantly lower than that in the absence of dexamethasone. Our data suggest that glucocorticoid suppresses the apoptotic process of osteoblasts by inhibiting the expression of both mFasL and sFasL derived from activated PBMC, mediating a protective effect against periarticular bone loss and bone erosion in inflammatory arthritis such as RA.

Hematuria in patients with renal hypouricemia

The characteristics of urate metabolism in renal hypouricemic patients with hematuria were studied to clarify the risk factors for hematuria in patients with renal hypouricemia. In 16 Japanese patients with isolated renal hypouricemia, urate metabolism was measured using the urate clearance study and the subtype of renal hypouricemia [defective presecretory reabsorption (Pre), defective postsecretory reabsorption (Post), enhanced tubular secretion (Secretion) and defective presecretory and postsecretory reabsorption (Pre&Post)] were determined by the pharmacological tests. Hematuria was seen in 7 out of the 16 patients (44%), all of whom were females (58%). Serum urate and urinary urate concentrations were significantly higher in the group with hematuria (Sur = 1.76 +/- 0.31 mg/dl and Uur/Ucr = 0.75 +/- 0.12: p<0.05) than in the group without hematuria (Sur = 1.44 +/- 0.46 mg/dl and Uur/Ucr = 0.56 +/- 0.04), although there was no difference in the urate excretion rate between the two groups. Hematuria was more likely to be accompanied by Post (75%) and Secretion (75%), which showed significantly higher urinary urate concentration (Uur/Ucr = 0.75 +/- 0.1 and 0.69 +/- 0.13, respectively) than by Pre (25%) and Pre&Post (0%), which showed lower urinary urate concentration (0.61 +/- 0.06 and 0.62 +/- 0.05, respectively). The risk factors for hematuria in patients with renal hypouricemia are the elevation of urinary urate concentration and the subtypes of Post and Secretion.

Expression of Shaker-type voltage-gated potassium channel genes in the guinea-pig

Few potassium channel genes have been isolated in the guinea-pig despite detailed electrophysiological characterization of potassium channels in the guinea-pig heart. We obtained partial clones of Shaker-type potassium channel genes in the guinea-pig and demonstrated their tissue distribution. Partial clones of the Shaker-type potassium channel genes were obtained by RT-PCR or genomic PCR. mRNA expression was measured by RNase protection assays in the heart, brain, and skeletal muscle. Three of the five obtained channel genes were expressed in the guinea-pig heart; Kv1.2, Kv1.3, and Kv1.6. Kv 1.6 expression was markedly at a higher level in the atrium than in the ventricle. Expression of the channel genes in the guinea-pig was different from that in human and rat, which may contribute to the species-specific action potential waveform.

Extrinsic intestinal reinnervation after canine small bowel autotransplantation

BACKGROUND

The process of extrinsic reinnervation after small bowel transplantation is poorly understood.

METHODS

Jejunal and ileal specimens, obtained from the dogs that underwent intestinal autotransplantation by an end-to end (E-E) or end-to-side arterial reconstruction, were analyzed at 1 (n = 7), 3 (n = 6), 6 (n = 6), 12 (n = 6), or 24 (n = 2) months and compared with control specimens (n = 7). Tissue catecholamine levels and indirect immunohistochemistry results for extrinsic neuropeptides, calcitonin gene-related peptide, neuropeptide Y, substance P, and tyrosine hydroxylase (TH) were examined.

RESULTS

Catecholamine levels in the grafts were undetectable until 6 months but increased significantly after 12 months, particularly in the E-E group. Immunohistochemistry results showed no significant indication of extrinsic reinnervation until 12 months, when TH fibers were observed in five of six dogs. The E-E group revealed some TH fibers extending across the arterial anastomosis toward the graft mesentery. Examination of the intestinal anastomosis at 12 months showed abundant peptidergic and TH extrinsic fibers in the host side, whereas there were few or none on the graft side.

CONCLUSIONS

These results suggest that extrinsic reinnervation of the graft intestinal wall does occur but requires a prolonged period, and the major route of extrinsic reinnervation is along the arterial axis of the intestinal graft, not beyond the enteric anastomosis.

A VATS lobectomy for lung cancer in a patient with an anomalous pulmonary vein: report of a case

A video-assisted right upper lobectomy was successfully performed on a 58-year-old man with an anomalous segmental pulmonary vein. The tumor was a peripherally located adenocarcinoma. The anomalous vein behind the right main bronchus was identified and safely divided. This case emphasized that to perform this procedure successfully, (1) a careful preoperative evaluation of the anatomy, including the presence of any possible vascular and/or bronchial anomalies, is necessary, and (2) if any anatomical structures cannot be determined intraoperatively, a conversion into an open procedure must immediately be undertaken.

Modulation of Fas-mediated apoptosis of human thyroid epithelial cells by IgG from patients with Graves' disease (GD) and idiopathic myxoedema

The expression of two autoimmune thyroid diseases. GD and idiopathic myxoedema, is associated with antibodies to the thyroid-stimulating hormone (TSH) receptor. Thyroid stimulating antibodies (TSAb) in GD are TSH agonists and cause hyperthyroidism as well as goitre, whereas thyroid stimulation blocking antibodies (TSBAb) in idiopathic myxoedema are TSH antagonists and cause hypothyroidism and thyroid atrophy. We investigated the effect of antibodies to TSH receptor on Fas-mediated apoptosis of thyroid epithelial cells (thyrocytes). Human IgG was isolated from healthy donors, patients with GD and idiopathic myxoedema. Human thyrocytes were obtained from surgical specimens. Thyrocytes were cultured in the presence or absence of human IgG with or without interferon-gamma (IFN-gamma) or IL-1beta for a specified time. After incubation, we examined the level of cAMP in cultured supernatants and both Fas and Bcl-2 expression on thyrocytes. In addition, we examined anti-Fas-mediated apoptosis of thyrocytes. Fas expression on thyrocytes was significantly down-regulated by Graves' IgG and TSH, although idiopathic myxoedema IgG did not affect Fas expression on thyrocytes. Idiopathic myxoedema IgG abrogated the effect of TSH on both cAMP production and inhibition of Fas expression on thyrocytes. Treatment of thyrocytes with IL-1beta or IFN-gamma caused a marked augmentation of Fas expression on thyrocytes. The increase of Fas expression of thyrocytes induced by IL-1beta or IFN-gamma was significantly suppressed in the presence of TSH or Graves' IgG. Anti-Fas-induced apoptosis of thyrocytes was observed in thyrocytes treated with IL-1beta or IFN-gamma, but was markedly inhibited in the presence of TSH or Graves' IgG. Furthermore, idiopathic myxoedema IgG abrogated most of the inhibitory effect of TSH on Fas-mediated apoptosis of thyrocytes treated with IL-1beta or IFN-gamma. Bcl-2 expression of thyrocytes did not change after stimulation with TSH, Graves' IgG, idiopathic myxoedema IgG, IL-1beta or IFN-gamma. These results suggest that TSAb found in Graves' patients may be potentially involved in the development of goitre by inhibition of Fas-mediated apoptosis of thyrocytes. In addition, TSBAb inhibit the action of TSH and increase the sensitivity toward Fas-mediated apoptosis of thyrocytes, inducing thyroid atrophy seen in patients with idiopathic myxoedema.

Fas/Fas ligand interaction regulates cytotoxicity of CD4+ T cells against staphylococcal enterotoxin B-pulsed endothelial cells

Infiltration of activated CD4+ T cells and apoptosis of endothelial cells are present in the synovium of rheumatoid arthritis (RA). Using staphylococcal enterotoxin B (SEB) as an antigen, we examined the possible role of antigen (Ag)-dependent activation of CD4+ T cells by endothelial cells, in inducing endothelial cell apoptosis. The human endothelial cell line, EA.hy926 cells, was cultured with or without interferon-gamma (IFN-gamma) and further incubated with CD4+ T cells in the presence or absence of SEB. After this cocultivation, the cytotoxicity and Fas ligand (FasL) expression of CD4+ T cells were examined. A small percentage of EA.hy926 cells expressed HLA-DR and -DQ, and this expression was significantly augmented after IFN-gamma stimulation. Anti-Fas IgM-induced apoptosis was exhibited by both unstimulated and IFN-gamma-stimulated EA.hy926 cells. Cytotoxicity of CD4+ T cells toward SEB-pulsed unstimulated EA.hy926 cells was detected. Furthermore, when CD4+ T cells were incubated with IFN-gamma-stimulated, SEB-pulsed EA.hy926 cells with augmented HLA-DR and -DQ expression, this cytotoxicity was more significant. The addition of anti-HLA-DR and -DQ monoclonal antibodies (mAbs) or human Fas chimeric protein (hFas-Fc) reduced the cytotoxicity. FasL expression was induced in CD4+ T cells cocultured with SEB-pulsed EA.hy926 cells, especially when the EA.hy926 cells were IFN-gamma-stimulated. Furthermore, the addition of mAbs against CD54 and CD58 inhibited both the cytotoxicity and FasL expression of CD4+ T cells induced by SEB-pulsed EA.hy926 cells, indicating the importance of costimulatory molecules on EA.hy926 cells in activating CD4+ T cells. Our results suggest that CD4+ T cells are activated by endothelial cells in an Ag-dependent manner and subsequently express FasL, which induces Fas-mediated apoptosis of endothelial cells. This phenomenon may counteract the growth of RA synovium by inhibiting the proliferation of endothelial cells.

Tonic block of the Na+ current in single atrial and ventricular guinea-pig myocytes, by a new antiarrhythmic drug, Ro 22-9194

Ro 22-9194 reduced the Na+ current in the atrial myocytes as well as ventricular myocytes in a tonic block fashion. Ro 22-9194 had a higher affinity to the inactivated state Na+ channels (KdI = 3.3 microM in atrial myocytes, KdI = 10.3 microM in ventricular myocytes) than to those in the rested state (KdR = 91 microM in atrial myocytes, KdR = 180 microM in ventricular myocytes), which indicated that Ro 22-9194 had a higher affinity to the Na+ channels in atrial myocytes than in ventricular myocytes. Ro 22-9194 shifted the inactivation curve in the hyperpolarized direction in both atrial and ventricular myocytes. These findings suggest that Ro 22-9194 more strongly inhibited the Na+ channel of the atrial myocytes of the diseased hearts with the depolarized membranes potentials than the Na+ channels in ventricular myocytes.

Degree of DNA unwinding caused by the binding of aclacinomycin A

The effect of drug binding on the geometry of DNA duplex (plasmid pBR322) has been examined using topoisomerase I relaxation followed by gel electrophoresis. The binding of one molecule of aclacinomycin A was found to cause an unwinding of the DNA double helix by an angle of 8 +/- 2 degrees in aqueous solution at 37 degrees C. The unwinding angle of daunomycin was 12 +/- 2 degrees, and that of ethidium bromide 15 +/- 3 degrees. To determine the unwinding angle, precise determination of the equilibrium constant of drug-DNA binding-dissociation reaction in the same buffer as that for the topoisomerase reaction (at 37 degrees C) was indispensable. This determination was made by ultraviolet absorption measurement of the same plasmid-drug system, followed by a Scatchard plot and analysis using McGhee-von Hippel's excluded site model. For the aclacinomycin-pBR322 system, the binding constant (K) was 7.2 x 10(4) M-1, and the number of base pairs in the single site of drug binding (n) was 4.0. For daunomycin-pBR322, K = 7.1 x 10(4) M-1 and n = 3.4, and for ethidium-pBR322, K = 4.0 x 10(4) M-1 and n = 3.3. On the basis of these experimental results, the possible role of the sugar moieties of these antitumour drugs, as well as that of intercalating chromophores, was discussed.

Influence of extracellular H+ and Ca2+ on Ro 22-9194-induced block of sodium current in cardiac myocytes

1. Ro 22-9194 reduced the Na current in ventricular myocytes in either a tonic block or phasic block manner. 2. Ro 22-9194 had a higher affinity to the inactivated state (Kdi = 10.3 microM) than to the rested state (Kdrest = 180 microM). 3. Extracellular acidification enhanced the tonic block but reduced the phasic block. 4. Elevation of extracellular Ca2+ inhibited the enhancing effects of extracellular acidification. 5. These findings suggest that Ro 22-9194 strongly inhibits Na+ channels of the ventricular myocytes of the diseased hearts, characterized by the depolarized cell membranes and by acid conditions.

Fas and Fas ligand interaction is necessary for human osteoblast apoptosis

We investigated the cellular and humoral interactions between peripheral blood mononuclear cells (PBMCs) and human osteoblasts, leading to apoptosis of osteoblasts. Human osteoblastic cell line MG63 and human primary osteoblast-like cells obtained from biopsy specimens were used in this study. PBMCs were isolated from healthy donors and cultured with or without stimulation by recombinant interleukin-2 followed by 12-o-tetradecanoylphorbol 13-acetate with ionomycin. Fas was functionally expressed on MG63 and primary osteoblast-like cells. Activated PBMCs expressed Fas ligand (FasL) strongly on their surface and killed MG63 and primary osteoblast-like cells. Cultured supernatants of activated PBMCs also induced apoptotic cell death of MG63 and primary osteoblast-like cells. In contrast, both unstimulated PBMCs and cultured supernatants of unstimulated PBMCs did not induce apoptosis of these cells. Furthermore, the cytotoxic effect and induction of apoptosis against MG63 and primary osteoblast-like cells by activated PBMCs and cultured supernatants were inhibited significantly by human Fas chimeric protein. Our data showed that human osteoblasts expressed Fas fuctionally and both membrane-type and soluble form FasL from activated PBMCs induced apoptosis of these cells, providing the one possible mechanism of bone loss in inflammatory diseases such as rheumatoid arthritis.

Organization of a large gene cluster encoding ribosomal proteins in the cyanobacterium Synechococcus sp. strain PCC 6301: comparison of gene clusters among cyanobacteria, eubacteria and chloroplast genomes

The structure of a large gene cluster containing 22 ribosomal protein (r-protein) genes of the cyanobacterium Synechococcus sp. strain PCC6301 is presented. Based on DNA and protein sequence analyses, genes encoding r-proteins L3, L4, L23, L2, S19, L22, S3, L16, L29, S17, L14, L24, L5, S8, L6, L18, S5, L15, L36, S13, S11, L17, SecY, adenylate kinase (AK) and the alpha subunit of RNA polymerase were identified. The gene order is similar to that of the E. coli S10, spc and alpha operons. Unlike the corresponding E. coli operons, the genes for r-proteins S4, S10, S14 and L30 are not present in this cluster. The organization of Synechococcus r-protein genes also resembles that of chloroplast (cp) r-protein genes of red and brown algal species. This strongly supports the endosymbiotic theory that the cp genome evolved from an ancient photosynthetic bacterium.

A novel mutation causing complete deficiency of thyroxine binding globulin

OBJECTIVE

Thyroxine binding globulin (TBG) is a serum protein that transports thyroxine. Three naturally occurring mutations have been reported to produce complete deficiency of TBG (TBG-CD). The first to be reported was TBG-CD5 in caucasian families of French-Canadian origin and consists of substitutions in exons 2 and 3. TBG-CD of English ethnic origin (TBG-CD6) is characterized by a thymine deletion in codon 165 (exon 1). In Japanese families with TBG-CD (TBG-CDJ), a variant has been characterized with a deletion of the first base of the codon for amino acid 352 (exon 4) in the common type TBG. In this communication we report a new type of TBG-CD in a family of Japanese ethnic origin that is characterized by a single nucleotide substitution in place of two nucleotides in exon 1. This is an uncommon mutation which we have been unable to find in other genes.

DESIGN

Exons of the TBG gene amplified by the polymerase chain reaction (PCR) were subcloned and sequenced. To examine for the presence of the same mutation in potentially affected individuals, we performed PCR using primer-directed mutagenesis or allele-specific amplification.

PATIENTS

The index case was of Japanese ethnic origin, and was diagnosed as having TBG deficiency on the basis of undetectable serum TBG. The patient consented to this evaluation and the protocol was in accordance with IRB standards.

MEASUREMENTS

Serum thyroid hormones, thyrotrophin binding inhibitory immunoglobulin and TBG concentrations were measured by conventional radio-immunoassay. Genomic DNA was extracted from white blood cells.

RESULTS

In the index case exons 2, 3 and 4 were normal, but nucleotides 144 (cytosine) and 145 (thymine) in exon 1 were substituted with a single base (adenine) which induced a frame shift in the reading frame, resulting in an early stop codon at codon 51. The patient and his daughters were confirmed as having this mutation using primer-directed mutagenesis or allele-specific amplification.

CONCLUSIONS

We have described a novel mutation in the TBG gene in a Japanese family. This results in a frame shift and premature stop codon, and was associated with undetectable serum TBG in the index case.

Inhibitory effects of interleukin-10 on synovial cells of rheumatoid arthritis

This paper describes the immunoregulatory effects of interleukin-10 (IL-10) on synovial cells in vitro. Synovial cells were cultured with IL-10 in the presence or absence of various cytokines. Following incubation, the costimulatory molecule expression on synovial cells and cytokine production in culture supernatants were analysed by an indirect immunofluorescence method and enzyme-linked immunosorbent assay, respectively. We also examined the effect of IL-10 on the function of synovial cells as antigen-presenting cells (APC). Synovial cells spontaneously express several kinds of costimulatory molecule and produce various kinds of cytokines. Stimulation of synovial cells with interferon-gamma (IFN-gamma), IL-1 beta, or 12-O-tetradecanoyl phorbol 13-acetate (TPA) markedly enhanced the expression of costimulatory molecules and cytokine production of these cells. Both spontaneous and up-regulated costimulatory molecule expression and cytokine production were significantly suppressed by the addition of IL-10. Autologous T-cell proliferation was stimulated by purified protein derivative (PPD) in IFN-gamma-treated synovial cells and treatment of these synovial cells with IL-10 also suppressed T-cell proliferation. Our results suggest that IL-10 has an inhibitory effect on synovial cells and is an important immunoregulatory component of the cytokine network in rheumatoid arthritis.

Polarized Raman spectroscopy of double-stranded RNA from bacteriophage phi6: local Raman tensors of base and backbone vibrations

Raman tensors for localized vibrations of base (A, U, G, and C), ribose and phosphate groups of double-stranded RNA have been determined from polarized Raman measurements on oriented fibers of the genomic RNA of bacteriophage phi6. Polarized Raman intensities for which electric vectors of both the incident and scattered light are polarized either perpendicular (I[bb]) or parallel (I[cc]) to the RNA fiber axis have been obtained by Raman microspectroscopy using 514.5-nm excitation. Similarly, the polarized Raman components, I(bc) and I(cb), for which incident and scattered vectors are mutually perpendicular, have been obtained. Spectra collected from fibers maintained at constant relative humidity in both H2O and D2O environments indicate the effects of hydrogen-isotopic shifts on the Raman polarizations and tensors. Novel findings are the following: 1) the intense Raman band at 813 cm(-1), which is assigned to phosphodiester (OPO) symmetrical stretching and represents the key marker of the A conformation of double-stranded RNA, is characterized by a moderately anisotropic Raman tensor; 2) the prominent RNA band at 1101 cm(-1), which is assigned to phosphodioxy (PO2-) symmetrical stretching, also exhibits a moderately anisotropic Raman tensor. Comparison with results obtained previously on A, B, and Z DNA suggests that tensors for localized vibrations of backbone phosphodiester and phosphodioxy groups are sensitive to helix secondary structure and local phosphate group environment; and 3) highly anisotropic Raman tensors have been found for prominent and well-resolved Raman markers of all four bases of the RNA duplex. These enable the use of polarized Raman spectroscopy for the determination of purine and pyrimidine base residue orientations in ribonucleoprotein assemblies. The present determination of Raman tensors for dsRNA is comprehensive and accurate. Unambiguous tensors have been deduced for virtually all local vibrational modes of the 300-1800 cm(-1) spectral interval. The results provide a reliable basis for future evaluations of the effects of base pairing, base stacking, and sequence context on the polarized Raman spectra of nucleic acids.

Raman scattering tensors of 5-iodouracil

Polarized Raman scattering measurements have been made of a single crystal of 5-iodouracil by the use of a Raman microscope with the 488.0 nm excitation. The crystal belongs to space group P2(1) (monoclinic), and Raman scattering intensities, corresponding to the a'a', bb, cc, a'b and bc components of the crystalline Raman tensor, have been determined for each prominent Raman band, where a' is the axis perpendicular to the c axis in the ac plane. From these experimental results, the shapes and orientations of the Raman scattering tensors have been derived for 6 base vibrations in the 5-iodouracil molecule. By comparing these tensors with those for thymine and pseudouridine vibrations, discussions were made of the polarizability oscillations caused by the normal vibrations localized in the pyrimidine base.

[Renal hypouricemia]

Renal hypouricemia (serum urate < 2.0 mg/dl) is the inborn disorder due to the impaired tubular urate transport resulted in an increased urate excretion. The inheritance shows an autosomal recessive trait. The prevalence of renal hypouricemia is 0.15% in the outpatients. Based on the 4-component model, by using the pharmacological inhibitor, renal hypouricemia is classified into the 4 types as follows, 1) defective presecretory reabsorption, 2) defective postsecretory reabsorption, 3) enhanced urate secretion, and 4) both defective presecretory and postsecretory reabsorption including the three subtypes. Although renal hypouricemia has asymptomatic as usual, acute renal failure and urolithiasis (hematuria) have been reported as the complication. We further introduced the novel pathophysiology of the renal hypouricemia such as the aciduria correlating to the accelerated urate excretion and the hyperoxipurinemia in this review.

Lack of B7-1/BB1 and B7-2/B70 expression on thyrocytes of patients with Graves' disease. Delivery of costimulatory signals from bystander professional antigen-presenting cells

We have previously demonstrated that thyrocytes from patients with Graves' disease induce autologous peripheral blood T cell proliferation in response to soluble antigens, and a synergistic augmentation of T cell response by adding suboptimal numbers of monocytes. In the present study, we examined the role of costimulatory molecules, expressed on the surface of thyrocytes and intrathyroidal mononuclear cells, in antigen-specific T cell proliferation. Intercellular associated molecule (ICAM)-1 and lymphocyte function associated antigen-3 were constitutively expressed on the surface of both normal and Graves' thyrocytes. However, ICAM-2, vascular cell adhesion molecule-1, B7-1, and B7-2 were not detected and induced by cytokines. B7-1, was expressed on intrathyroidal monocytes only, while B7-2 was present on intrathyroidal lymphocytes, peripheral blood monocytes, and intrathyroidal monocytes. Furthermore, the density of B7-2 was higher on intrathyroidal monocytes than on peripheral blood monocytes. The intensity of CD28 expression on intrathyroidal CD8bright+ cells was less than that on peripheral blood CD8bright+ cells. The antigen-specific T cell response induced by thyrocytes was blocked completely by anti-human leukocyte antigen-DR monoclonal antibody (mAb) and partially by anti-ICAM-1 mAb and anti-lymphocyte function associated antigen-3 mAb. Furthermore, the synergistic augmentation of T cell response, induced by the addition of suboptimal number of monocytes, was suppressed completely by combining anti-B7-1 mAb and anti-B7-2 mAb, to a level equivalent to that observed when thyrocytes were used alone as antigen-presenting cells. Our results suggest that T cell proliferation was induced by cooperation of thyrocytes and infiltrating professional antigen-presenting cells.

Pulmonary resection for metastatic colorectal cancer: experiences with 159 patients

We reviewed the clinical courses of 159 patients between February 1967 and May 1995 for the purpose of examining the survival of patients who had pulmonary resection for metastatic colorectal cancer. The cumulative survivals at 5 years and 10 years were 40.5% and 27.7%, respectively. Fifteen patients (10%) were alive more than 10 years after the thoracotomy without any evidence of recurrence. The cumulative survival at 5 years for 39 patients who had hepatic metastases before thoracotomy was 33%. There was a statistically significant difference in survival between patients with extrapulmonary metastases and those with only intrapulmonary metastases before thoracotomy. The number of pulmonary metastases and the presence of hilar or mediastinal lymph node metastases affected postthoracotomy survival. There was no significant difference in survival on the basis of sex, age, location of the primary cancer, size of the pulmonary tumors, mode of operation, or disease-free interval. Surgical treatment for pulmonary metastases from colorectal cancer in selected patients, even those who had hepatic metastases before thoracotomy, might improve prognosis.

Orientation of tryptophan-26 in coat protein subunits of the filamentous virus Ff by polarized Raman microspectroscopy

The Ff filamentous virus, which includes the closely related strains fd, fl and M13, serves as a model for membrane protein assembly and is employed extensively as a cloning vector and vehicle for peptide display. The threadlike virion (approximately 6 x 880 nm) comprises a single-stranded DNA genome sheathed by approximately 2700 copies of a 50-residue alpha-helical subunit, the product of viral gene VIII. The pVIII subunit contains a single tryptophan residue (tryptophan-26) which is essential for assembly. We have employed polarized Raman microspectroscopy to determine the orientation of tryptophan-26 in pVIII subunits of oriented fd fibers. The present application is based upon the transfer of tryptophan Raman tensors from a recent study of N-acetyl-L-tryptophan single crystals [Tsuboi et al. (1996) J. Mol. Struct. 379, 43-50]. The polarized Raman spectra of fd indicate that the plane of the indole ring in each pVIII subunit is close to parallel to the virion axis. In this orientation, the line connecting indole ring atoms N1 and C2 is nearly perpendicular to the virion axis, while the indole pseudo-2-fold axis (a line connecting atom C2 to the midpoint of the C5-C6 bond) is approximately 36 degrees from the virion axis. We have used the present results in combination with preferred tryptophan side-chain torsions [chi 1 (C3-C beta-C alpha-N) and chi 2.1 (C2-C3-C beta-C alpha)] in other proteins and a previously determined experimental value of chi 2.1 in fd [Aubrey. K. L., & Thomas, G. J., Jr. (1991) Biophys, J. 60, 1337-1349] to propose a detailed molecular model for the orientation of the tryptophan-26 side chain in the native virus.

Inhibition of Fas antigen-mediated apoptosis of rheumatoid synovial cells in vitro by transforming growth factor beta 1

OBJECTIVE

To investigate the mitogenic and anti-apoptotic effects of transforming growth factor beta 1 (TGF beta 1) on rheumatoid synovial cells in vitro.

METHODS

Synovial cells were cultured with or without TGF beta 1. After incubation, the proliferative response of synovial cells and the expression of Fas antigen and bcl-2 on synovial cells were examined. Finally, Fas antigen-mediated apoptosis of synovial cells was investigated by the addition of anti-Fas antibody.

RESULTS

TGF beta 1 enhanced the proliferation of synovial cells in a dose-dependent manner. In addition, Fas antigen expression on synovial cells was inhibited by the addition of TGF beta 1 with up-regulation of bcl-2 expression. The addition of anti-Fas antibody induced synovial cell apoptosis. However, stimulation of synovial cells with TGF beta 1 became markedly resistant to Fas antigen-mediated apoptosis. The results were not affected by the addition of a neutralizing antibody to platelet-derived growth factor type AA (PDGF-AA), which suggests that the effect of TGF beta 1 on synovial cells was promoted via PDGF-AA-independent mechanisms.

CONCLUSION

Our results suggest that TGF beta 1 promotes synovial cell proliferation through its mitogenic effect on synovial cells and interference with the apoptotic process mediated by the Fas antigen, resulting in the perpetuation of the synovial hyperplasia in patients with rheumatoid arthritis.