DIX domains of Dvl and axin are necessary for protein interactions and their ability to regulate beta-catenin stability

The N-terminal region of Dvl-1 (a mammalian Dishevelled homolog) shares 37% identity with the C-terminal region of Axin, and this related region is named the DIX domain. The functions of the DIX domains of Dvl-1 and Axin were investigated. By yeast two-hybrid screening, the DIX domain of Dvl-1 was found to interact with Dvl-3, a second mammalian Dishevelled relative. The DIX domains of Dvl-1 and Dvl-3 directly bound one another. Furthermore, Dvl-1 formed a homo-oligomer. Axin also formed a homo-oligomer, and its DIX domain was necessary. The N-terminal region of Dvl-1, including its DIX domain, bound to Axin directly. Dvl-1 inhibited Axin-promoted glycogen synthase kinase 3beta-dependent phosphorylation of beta-catenin, and the DIX domain of Dvl-1 was required for this inhibitory activity. Expression of Dvl-1 in L cells induced the nuclear accumulation of beta-catenin, and deletion of the DIX domain abolished this activity. Although expression of Axin in SW480 cells caused the degradation of beta-catenin and reduced the cell growth rate, expression of an Axin mutant that lacks the DIX domain did not affect the level of beta-catenin or the growth rate. These results indicate that the DIX domains of Dvl-1 and Axin are important for protein-protein interactions and that they are necessary for the ability of Dvl-1 and Axin to regulate the stability of beta-catenin.

Identification of a novel GC-rich 113-nucleotide region to complete the circular, single-stranded DNA genome of TT virus, the first human circovirus

The sequence data (H. Okamoto et al., Hepatol. Res. 10:1-16, 1998) of a newly discovered single-stranded DNA virus, TT virus (TTV), showed that it did not have the terminal structure typical of a parvovirus. Elucidation of the complete genome structure was necessary to understand the nature of TTV. We obtained a 1.0-kb amplified product from serum samples of four TTV carriers by an inverted, nested long PCR targeted for nucleotides (nt) 3025 to 3739 and 1 to 216 of TTV. The sequence of a clone obtained from serum sample TA278 was compared with those registered in GenBank. The complete circular TTV genome contained a novel sequence of 113 nt (nt 3740 to 3852 [=0]) in between the known 3'- and 5'-end arms, forming a 117-nt GC-rich stretch (GC content, 90.6% at nt 3736 to 3852). We found a 36-nt stretch (nt 3816 to 3851) with an 80.6% similarity to chicken anemia virus (CAV) (nt 2237 to 2272 of M55918), a vertebrate circovirus. A putative SP-1 site was located at nt 3834 to 3839, followed by a TATA box at nt 85 to 90, the first initiation codon of a putative VP2 at nt 107 to 109, the termination codon of a putative VP1 at nt 2899 to 2901, and a poly(A) signal at nt 3073 to 3078. The arrangement was similar to that of CAV. Furthermore, several AP-2 and ATF/CREB binding sites and an NF-kappaB site were arranged around the GC-rich region in both TTV and CAV. The data suggested that TTV is circular and similar to CAV in its genomic organization, implying that TTV is the first human circovirus.

Inhibition of the Wnt signaling pathway by Idax, a novel Dvl-binding protein

In attempting to clarify the roles of Dvl in the Wnt signaling pathway, we identified a novel protein which binds to the PDZ domain of Dvl and named it Idax (for inhibition of the Dvl and Axin complex). Idax and Axin competed with each other for the binding to Dvl. Immunocytochemical analyses showed that Idax was localized to the same place as Dvl in cells and that expression of Axin inhibited the colocalization of Dvl and Idax. Further, Wnt-induced accumulation of beta-catenin and activation of T-cell factor in mammalian cells were suppressed by expression of Idax. Expression of Idax in Xenopus embryos induced ventralization with a reduction in the expression of siamois, a Wnt-inducible gene. Idax inhibited Wnt- and Dvl- but not beta-catenin-induced axis duplication. It is known that Dvl is a positive regulator in the Wnt signaling pathway and that the PDZ domain is important for this activity. Therefore, these results suggest that Idax functions as a negative regulator of the Wnt signaling pathway by directly binding to the PDZ domain of Dvl.

Radiommunoassays for the 70,000-molecular-weight glycoproteins of endogenous mouse type C viruses: viral antigen expression in normal mouse tissues and sera

Genetic information coding for type C RNA viruses is transmitted within the DNA of mouse cells. At least three endogenous viruses have so far been immunologically distinguished by radioimmunoassays for their 12,000-molecular-weight polypeptides (p12). In the present study, the 70,000-molecular-weight glycoproteins (gp70) of three prototype viruses were purified, and competition radioimmunoassays were developed for each. By use of these immunoassays, the antigenic determinants of gp70's of different classes of endogenous virus, isolated from the same and from a variety of other mouse strains, were readily discriminated. In contrast, viruses of the same class were indistinguishable. These findings further document the existence of three distinct endogenous viruses of mouse cell. The levels of type C viral gp70 were quantitated in tissues and sera of several inbred strains. The pattern of immunological reactivity of the gp70 detected in serum was indistinguishable from that of the viral gp70 partially purified from tissues of the same strain. Moreover, in each case it was indistinguishable from that of a specific class of endogenous virus. In virus-negative tissues of BALB/c and NIH Swiss mice, the viral gp70 detected was shown to be representative of a class III endogenous virus whose p12 polypeptide was also expressed by the same cells.

A novel beta-catenin-binding protein inhibits beta-catenin-dependent Tcf activation and axis formation

beta-Catenin is efficiently phosphorylated by glycogen synthase kinase-3beta in the Axin complex in the cytoplasm, resulting in the down-regulation. In response to Wnt, beta-catenin is stabilized and translocated into the nucleus where it stimulates gene expression through Tcf/Lef. Here we report a novel protein, designated Duplin (for axis duplication inhibitor), which negatively regulates the function of beta-catenin in the nucleus. Duplin was located in the nucleus. Duplin bound directly to the Armadillo repeats of beta-catenin, thereby inhibiting the binding of Tcf to beta-catenin. It did not affect the stability of beta-catenin but inhibited Wnt- or beta-catenin-dependent Tcf activation. Furthermore, expression of Duplin in Xenopus embryos inhibited the axis formation and beta-catenin-dependent axis duplication, and prevented the beta-catenin's ability to rescue ventralizing phenotypes induced by ultraviolet light irradiation. Thus, Duplin is a nuclear protein that inhibits beta-catenin signaling.

Course and outcome of tubulointerstitial nephritis and uveitis syndrome

We report here the clinical features and outcomes of 10 patients, aged 11 to 21 years (median, 13.0), with idiopathic tubulointerstitial nephritis (TIN) and uveitis syndrome (TINU syndrome). The initial symptoms were visual impairment in 7 patients and prolonged fever, anemia, or asthenia in 4 patients. An increase in urinary beta(2)-microglobulin was noticed at the initial checkup in all patients, including 2 patients who showed the normal ranges of 24-hour protein excretion. Creatinine clearance was decreased in 8 patients. TIN was found simultaneously with ocular symptoms in 7 patients and preceded these symptoms in the remaining 3 patients. Percutaneous renal biopsy indicated tubulointerstitial lesions in varying degrees. The histological grade of TIN was correlated with urinary beta(2)-microglobulin levels. Systemic steroid therapy was performed in 7 patients because of the progression of uveitis. The 10 patients were followed-up for 16 to 94 months (median, 31.0 months). In all patients, creatinine clearance recovered to the normal ranges (>/=70 mL/min/1.73 m(2)) mostly within 1 year. Urinary beta(2)-microglobulin excretion gradually declined but was slightly elevated in 4 patients at the latest checkup. Uveitis recurred in all 10 patients, which did not affect the renal status. Our findings indicate that early referral of patients from ophthalmologists and determination of beta(2)-microglobulin in the urine is helpful for the early discovery of TINU syndrome. In children and adolescents with this syndrome, TIN spontaneously resolves and its long-term prognosis is good, but uveitis often relapses. Systemic steroids may be required for uveitis, but not for TIN.

Significance of postnatal mother-to-child transmission of human T-lymphotropic virus type-I on the development of adult T-cell leukemia/lymphoma

In order to shed light on the mode of HTLV-I infection by mother-to-child transmission, we examined sera of school children in a highly endemic town on two separate occasions at a 6-year interval. The carrier rates in ages 15-17, 8.7 and 2.1%, were significantly higher than that in ages 6-8, 1.7 and 0.4%, in studies. The latter survey showed a significantly lower carrier rate in each age group. Moreover, the carrier rates of those students born in 1965-1967 and 1968-1970 were stable in the interval. The data suggested that carrier rates of children at certain ages are reflected by the date of birth rather than by age. A prospective survey of children born of carrier mothers found the overall carrier rate to be approximately 25%, which did not increase with their age. There was no sexual difference in the carrier rate of children: 5/25 in male and 9/34 in females (X2 = 0.3). Carrier mothers could be separated into two groups: HTLV-I antigen-positive mothers and negative mothers. Nine out of 19 antigen-positive mothers (47%) and 2 of 19 antigen-negative mothers (11%) had carrier children (X2 = 6.3). Twelve of 30 children born of antigen-positive carrier mothers (40%) were carriers, in contrast to 2 of 24 children (8%) of antigen-negative mothers (X2 = 7.8). Furthermore, 12 of 14 carrier children (86%) were of antigen-positive mothers. This suggests that postnatal but early transmission of HTLV-I plays a significant role in the maintenance of HTLV-I endemy and the development of adult T-cell leukemia/lymphoma.

Prospective reevaluation of risk factors in mother-to-child transmission of hepatitis C virus: high virus load, vaginal delivery, and negative anti-NS4 antibody

Of 21,791 pregnant women screened in Tottori Prefecture, Japan, 127 (0.58%) were positive for anti-hepatitis C virus (HCV) antibody and 84 (0.39%) were positive for HCV RNA. Of 84 children followed up for at least 6 months, 7 (8%) were infected. All of them were born to 26 mothers with a high virus load (HVL; >/=2.5x106 RNA copies/mL [27%]), compared with 0 of 58 children born to non-HVL mothers (P<.001). Because all the infected children were vaginally delivered, the infection rate among 16 vaginally delivered children born to the HVL mothers was as high as 44%. The prevalence of anti-NS4 antibody in the mothers with an infectious HVL was significantly lower than that in the mothers with a noninfectious HVL (P=.048). Analysis of our results suggests that maternal HVL, vaginal delivery, and negative anti-NS4 antibody are significant risk factors for the mother-to-child transmission of HCV.

Role of HGF/c-met system in invasion and metastasis of oral squamous cell carcinoma cells in vitro and its clinical significance

We examined the role of the hepatocyte growth factor (HGF)/c-met system on invasion and metastasis of oral squamous cell carcinoma (SCC) cells. In monolayer culture, exogenous HGF marginally affected the growth of oral SCC cells (BHY, HN, IH) and human gingival epithelial cells (GE). In type I collagen matrix, however, HGF significantly enhanced the invasive growth of the cancer cells (p < 0.05). We detected the expression of c-met (HGF receptor) mRNA in all of the cancer cells, but not in human gingival fibroblasts (GF). Oral SCC cells did not secret HGF protein into the medium, but GF secreted a large amount of HGF protein (15 ng/ml). Furthermore, HGF markedly enhanced the migration of cancer cells in a Transwell invasion chamber. Then, we examined the serum levels of HGF in oral SCC patients, or HGF concentrations in oral cancer tissues. Serum levels of HGF in the patients were significantly higher than those in healthy volunteers (p < 0.05). After initial treatment, all of the tumor-free survivors showed a marked decline in the serum HGF levels. Furthermore, HGF concentrations in metastatic cancer tissues were significantly higher than those of non-metastatic cancer tissues and normal gingiva (p < 0.01). These results suggest that HGF plays an important role in invasion and metastasis of oral SCC cells as a paracrine factor, and an elevated HGF level in the cancer tissue can be a predictive marker for metastasis formation in patients with oral SCC.

Synthesis and Reactivity of Dimeric Ar‘TlTlAr‘ and Trimeric (Ar‘ ‘Tl)3(Ar‘, Ar‘ ‘ = Bulky Terphenyl Group) Thallium(I) Derivatives: Tl(I)−Tl(I) Bonding in Species Ligated by Monodentate Ligands

The synthesis and characterization of three new organothallium(I) compounds are reported. Reaction of (Ar'Li)(2) (Ar' = C(6)H(3)-2,6-(C(6)H(3)-2,6-Pr(i)(2))(2)) and Ar"Li (Ar" = C(6)H(3)-2,6-(C(6)H(3)-2,6-Me(2))(2)) with TlCl in Et(2)O afforded (Ar'Tl)(2) (1) and (Ar' 'Tl)(3) (2). The "dithallene" 1 is the heaviest group 13 dimetallene and features a planar, trans-bent structure with Ar'Tl-Tl = 119.74(14) degrees and Tl-Tl = 3.0936(8) A. Compound 2 is the first structurally characterized neutral, three-membered ring species of formula c-(MR)(3) (M = Al-Tl; R = organo group). The Tl(3) ring has Tl-Tl distances in the range ca. 3.21-3.37 A as well as pyramidal Tl geometries. The Tl-Tl bonds in 1 and 2 are outside the range (2.88-2.97 A) of Tl-Tl single bonds in R(2)TlTlR(2) compounds. The weak Tl-Tl bonding in 1 and 2 leads to their dissociation into Ar'Tl and Ar' 'Tl monomers in hexane. The Ar'Tl monomer behaves as a Lewis base and readily forms a 1:1 donor-acceptor complex with B(C(6)F(5))(3) to give Ar'TlB(C(6)F(5))(3), 3. Adduct 3 features an almost linear thallium C(ipso)-Tl-B angle of 174.358(7) degrees and a Tl-B distance of 2.311(2) A, which indicates strong association. Treatment of 1 with a variety of reagents resulted in no reactions. The lower reactivity of 1 is in accord with the reluctance of Tl(I) to undergo oxidation to Tl(III) due to the unreactive character of the 6s(2) electrons.

Population dynamics of phenol-degrading bacteria in activated sludge determined by gyrB-targeted quantitative PCR

A method for quantifying bacterial populations introduced into an activated-sludge microbial community is described. The method involves extraction of DNA from activated sludge, appropriate dilution of the extracted DNA with DNA extracted from nonintroduced activated sludge, PCR amplification of a gyrB gene fragment from the introduced strain with a set of strain-specific primers, and quantification of the electrophoresed PCR product by densitometry. The adequacy of the method was examined by analyzing the population dynamics of two phenol-degrading bacteria, Pseudomonas putida BH and Comamonas sp. strain E6, that had been introduced into phenol-digesting activated sludge. The density of each of the two populations determined by the PCR method immediately after the introduction was consistent with the density estimated from a plate count of the inoculum. This quantitative PCR method revealed different population dynamics for the two strains in the activated sludge under different phenol-loading conditions. The behavior of both of these strains in the activated sludge reflected the growth kinetics of the strains determined in laboratory axenic cultures.

Three spliced mRNAs of TT virus transcribed from a plasmid containing the entire genome in COS1 cells

A permuted whole-genome construct of a TT virus (TTV), named VT416, had 3,852 nucleotides (nt) 98.2% similar to the prototype TA278 genome. To allow the transcription of TTV from the internal promoter, pBK*VT416(1.3G), carrying 1.3 units of VT416, was constructed. The poly(A)(+) RNAs expressed in COS1 cells 48 h posttransfection contained three TTV mRNA species 3.0, 1.2, and 1.0 kb in length, which were recovered in the 13 DNA clones from a lambda phage cDNA library. These mRNAs in the antigenomic orientation possessed in common the 3' terminus downstream of a poly(A) signal (A(3073)ATAAA) and the 5' terminus downstream of a cap site (C(98)ACTTC). A common splicing to join nt 185 with nt 277 was detected in all mRNAs. The coding region of the largest open reading frame (ORF) was maintained in 3.0-kb mRNA, because this splicing was located upstream of its initiation codon (A(589)TG). The second splicing was detected in 1.2-kb mRNA to join nt 711 with nt 2374 and in 1.0-kb mRNA to bind nt 711 to nt 2567. They linked a proposed ORF2 to another ORF for creating new ORFs over nt 2374 to 2872 in frame 2 and nt 2567 to 3074 in frame 3. The donor and acceptor sites of all three splicings matched the consensus sequence and were conserved in most of the 16 TTVs of distinct genotypes retrieved from the database. The observed transcription profile is unique to TTV among known members in the family Circoviridae.

Urinary transforming growth factor-beta in patients with glomerular diseases

We measured the urinary levels of active transforming growth factor-beta (TGF-beta) by enzyme-linked immunosorbent assay in 12 healthy controls and 42 patients with various glomerular diseases, including mesangial proliferative (IgA nephritis, Henoch-Schönlein purpura nephritis, and IgA-negative mesangial proliferative glomerulonephritis) and non-proliferative (minimal change nephrotic syndrome and focal glomerulosclerosis) types. Urinary TGF-beta, expressed as a ratio to urinary creatinine (ng/mg creatinine), was elevated in patients with IgA nephritis and focal glomerulosclerosis, and was significantly higher than in patients with other types of glomerular diseases and healthy controls. There was a significant correlation between urinary TGF-beta levels and the grade of interstitial fibrosis. Among patients with proliferative-type disease, urinary TGF-beta was significantly correlated with the grade of mesangial matrix increase and the magnitude of proteinuria. The relationship between urinary TGF-beta levels and the immunostaining intensity of TGF-beta in the glomeruli was not significant. These results indicated that urinary TGF-beta reflects the grade of interstitial fibrosis in glomerular diseases and also the mesangial matrix increase in proliferative-type glomerulonephritis. Measuring TGF-beta levels in the urine might be helpful in monitoring patients with some types of glomerular disease.

A nationwide survey for prevalence of hepatitis E virus antibody in qualified blood donors in Japan

BACKGROUND AND OBJECTIVES

  In previous studies, we reported the transmission of hepatitis E virus (HEV) by transfusion, and the frequent detection of HEV markers in Japanese blood donors with elevated ALT levels. For the current study, we carried out a nationwide survey of the prevalence of IgG anti-HEV in qualified blood donors throughout Japan.

MATERIALS AND METHODS

The 12,600 samples from qualified blood donors were collected from seven blood centres (1800 per centre) representing nearly all regions of Japan. Samples were from age- and sex-matched blood donors who tested negative for all the current blood screening tests. The samples were screened using the in-house IgG anti-HEV ELISA. Sequentially, the positive samples were tested by the commercial IgG anti-HEV ELISA.

RESULTS

Of 12,600 samples, 431 (3·4%) were regarded as positive for IgG anti-HEV. The prevalence of IgG anti-HEV was higher in eastern Japan (5·6%) than in western Japan (1·8%) (P<0·001), and was also age-dependent and higher in men (3·9%) than in women (2·9%) (P=0·002).

CONCLUSION

The spread of the domestic infection of HEV was observed in qualified blood donors in Japan. A higher prevalence of IgG anti-HEV was observed in male donors, older donors and in donors residing in eastern Japan. Further studies are necessary to clarify the potential risk of transfusion-transmission of HEV in Japan.

Exercise-induced changes in the expression of surface adhesion molecules on circulating granulocytes and lymphocytes subpopulations

This study examined the relationship between exercise-induced changes in the concentration of circulating immunocompetent cells and their surface expression of adhesion molecules: L-selectin (CD62L) and three beta 2-integrins [LFA-1(CD11a/CD18), Mac-1 (CD11b/CD18), and p150/95(CD11c/CD18)]. Eight young male volunteers exercised on a cycle ergometer for 60 min at 60% maximal oxygen uptake. Peripheral blood samples, collected every 30 min throughout exercise and during the 2-h recovery period, were used for flow-cytometric analysis. The experimental results were compared with control data obtained ever 60 min at corresponding times of the nonexercise day. The exercise regimen induced a granulocytosis and a lymphocytosis, mainly due to an elevation of CD8+ and CD16+ cells. During recovery, a further granulocytosis occurred but accompanied by a lymphopenia. The increased CD8+ cell-count during exercise was characterized by a selective mobilization of the CD62L- and CD11ahigh cells, i.e. primed CD8+ cells. A postexercise suppression of CD4+ cell-count was derived only from CD62L+ cells. The CD11b+ and CD11c+ lymphocytes also increased during exercise, largely attributable to an increase in CD16+ cells which co-expressed CD11b and CD11c molecules. The CD62L surface density of granulocytes increased significantly during recovery. This resulted from a selective influx of CD62Lhigh granulocytes into the circulation. There were no significant changes in per-cell density of the three beta 2-integrins on granulocytes and lymphocytes throughout the experimental period. These results suggest that the cell-surface expression of CD62L (and CD11a) molecules is associated with the differential mobilization of CD8+ cells during exercise, the postexercise suppression of CD4+ cell-counts and the granulocytosis following exercise.

Biochemical characterization of various catalytic complexes of the brain platelet-activating factor acetylhydrolase

Brain intracellular platelet-activating factor acetylhydrolase (PAF-AH) isoform I is a member of a family of complex enzymes composed of mutually homologous alpha(1) and alpha(2) subunits, both of which account for catalytic activity, and the beta subunit. We previously demonstrated that the expression of one catalytic subunit, alpha(1), is developmentally regulated, resulting in a switching of the catalytic complex from alpha(1)/alpha(2) to alpha(2)/alpha(2) during brain development (Manya, H., Aoki, J., Watanabe, M., Adachi, T., Asou, H., Inoue, Y., Arai, H., and Inoue, K. (1998) J. Biol. Chem. 273, 18567-18572). In this study, we explored the biochemical differences in three possible catalytic dimers, alpha(1)/alpha(1), alpha(1)/alpha(2), and alpha(2)/alpha(2). The alpha(2)/alpha(2) homodimer exhibited different substrate specificity from the alpha(1)/alpha(1) homodimer and the alpha(1)/alpha(2) heterodimer, both of which showed similar substrate specificity. The alpha(2)/alpha(2) homodimer hydrolyzed PAF and 1-O-alkyl-2-acetyl-sn-glycero-3-phosphorylethanolamine (AAGPE) most efficiently among 1-O-alkyl-2-acetyl-phospholipids. In contrast, both alpha(1)/alpha(1) and alpha(1)/alpha(2) hydrolyzed 1-O-alkyl-2-acetyl-sn-glycero-3-phosphoric acid more efficiently than PAF. AAGPE was the poorest substrate for these enzymes. The beta subunit bound to all three catalytic dimers but modulated the enzyme activity in a catalytic dimer composition-dependent manner. The beta subunit strongly accelerated the enzyme activity of the alpha(2)/alpha(2) homodimer but rather suppressed the activity of the alpha(1)/alpha(1) homodimer and had little effect on that of the alpha(1)/alpha(2) heterodimer. The (His(149) to Arg) mutant beta, which has been recently identified in isolated lissencephaly sequence patients, lost the ability to either associate with the catalytic complexes or modulate their enzyme activity. The enzyme activity of PAF-AH isoform I may be regulated in multiple ways by switching the composition of the catalytic subunit and by manipulating the beta subunit.

Clinical and radiological features in four adolescents with nutcracker syndrome

We describe four adolescents with the nutcracker syndrome. In three patients, the nutcracker syndrome was detected through mass urinary screening; the other patient was diagnosed after a sudden onset of dark urine. All patients underwent magnetic resonance angiography (MRA) for diagnosis of the nutcracker syndrome, which revealed dilatation of the left renal vein ranging between 7.4 and 13 mm at the hilar portion. A renal biopsy, performed in three patients, showed no remarkable abnormalities in the glomerulus or tubulointerstitial tissue. The patients complained of physical discomfort, including headache, abdominal pain, fainting, and tachycardia mimicking clinical symptoms of an orthostatic disturbance. However, no chronic systemic diseases were detected in any of the patients after repeated laboratory examinations. An orthostatic disturbance preceded diagnosis in three patients. This report indicates that the nutcracker syndrome may cause serious physical ailments that clinically mimic an orthostatic disturbance. It may be important to identify the nutcracker syndrome among children who manifest non-specific physical complaints. MRA could be a safe and reliable method for diagnosing the nutcracker syndrome.

A reversible valence equilibrium in a heavier main group compound

The addition of LiPh to Ar*SnCl (Ar* = C6H3-2,6-Trip2; Trip = C6H2-2,4,6-iPr3) at low temperature afforded the Sn(1)-Sn(III) species Ar*SnSnPh2Ar*, which exists in equilibrium with the Sn(II) compound Ar*SnPh. It is the first example of a room-temperature equilibrium of compounds involving main group elements in different oxidation states.

Terphenyl Ligand Stabilized Lead(II) Derivatives: Steric Effects and Lead−Lead Bonding in Diplumbenes

The reaction of PbBr(2) with the lithium reagents LiC(6)H(3)-2,6-(C(6)H(3)-2,6-Pr(i)(2))(2) (LiArPr(i)(2)) and Et(2)O.LiC(6)H(3)-2,6-(2,6-Pr(i)-4-Bu(t)C(6)H(2))(2) (Et(2)O.LiArPr(i)(2)Bu(t)) furnished the bromide bridged organolead(II) halides [Pb(mu-Br)ArPr(i)(2)](2) (1) and[Pb(mu-Br)ArPr(i)(2)Bu(t)](2) (2) as orange crystals. Treatment of 1 with a stoichiometric amount of methylmagnesium bromide resulted in the "diplumbene" Pr(i)(2)Ar(Me)PbPb(Me)ArPr(i)(2) (3). The addition of 1 equiv of 4-tert-butylphenylmagnesium bromide to 1 afforded the feebly associated, Pb-Pb bonded species [Pb(C(6)H(4)-4-Bu(t))ArPr(i)(2)](2) (4), whereas the corresponding reaction of tert-butylmagnesium chloride and 1 afforded the monomer Pb(Bu(t))ArPr(i)(2) (5). The reaction of the more crowded aryl lead(II) bromide [Pb(mu-Br)ArPr(i)(3)](2) (Ar = C(6)H(3)-2,6(C(6)H(2)-2,4,6-Pr(i)(3))(2)) with 4-isopropyl-benzylmagnesium bromide or LiSi(SiMe(3))(3) yielded the monomers 6, [Pb(CH(2)C(6)H(4)-4-Pr(i))ArPr(i)(3)], or 7, [Pb(Si(SiMe(3))(3))ArPr(i)(3)]. All compounds were characterized with use of X-ray crystallography, (1)H, (13)C, and (207)Pb NMR (3-7), and UV-vis spectroscopy. The dimeric Pb-Pb bonded (Pb-Pb = 3.1601(6) A) structure of 3 may be contrasted with the previously reported monomeric structure of Pb(Me)ArPr(i)(3), which differs from 3 only in that it has para Pr(i) substituents on the flanking aryl rings. The presence of these groups is sufficient to prevent the weak Pb-Pb bonding seen in 3. The dimer 4 displays a Pb-Pb distance of 3.947(1) A, which indicates a very weak lead-lead interaction, and it is possible that this close approach could be caused by packing effects. The monomeric structures of 6 and 7 are attributable to steric effects and, in particular, to the large size of ArPr(i)(3).

Differential expression of helper viral structural polypeptides in cells transformed by clonal isolates of woolly monkey sarcoma virus

Cell lines transformed by woolly monkey sarcoma virus (WSV) in the absence of infectious virus production were analyzed for the expression of woolly monkey helper viral p30, p12, and gp70 antigens. Several lines produced high levels of both p30 and p12, whereas gp70 was not detectable. One transformed clone expressed only p12, and in another cell line, none of the helper viral antigens were detected. The properties of each sarcoma virus bred true upon transmission, indicating that each variant represents a distinct genotype. The different cell lines were examined with respect to properties characteristic of the transformed state. The in vitro growth properties and oncogenicity of each WSV-transformed clone were indistinguishable, indicating that transformation by WSV occurs independently of the expression of at least three helper viral polypeptides.

Follow-up study of children with nephrotic syndrome treated with a long-term moderate dose of cyclosporine

Because of its potential for chronic nephrotoxicity, the long-term use of cyclosporine A (CsA) as treatment for nephrotic syndrome (NS) is controversial. The clinical outcome of patients with NS treated with CsA is unclear. We retrospectively evaluated 35 children with idiopathic NS, 24 with steroid-dependent NS (SDNS), and 11 with steroid-resistant NS (SRNS), who received CsA therapy for more than 12 months (median, 23 months) at the dosage maintaining 50 to 120 ng/mL in trough level. For SDNS patients, CsA was added to prednisolone after complete remission was achieved. For SRNS patients, CsA was used in combination with alternate-day prednisolone. Initial renal histology showed minimal changes (MC) in 28 patients (including all of the patients with SDNS) and focal segmental glomerulosclerosis (FSGS) in seven patients. The patients were followed up for 2 to 10.5 years (median, 6.5 years) after the termination of the CsA therapy. In SDNS patients, the relapse rate, dosage of prednisolone, standard deviation score for height, and body mass index significantly improved during CsA treatment. The follow-up study showed the proportion of SDNS decreased to 13 of 24 (54%) patients. In SRNS patients, CsA therapy induced remission in 8 of 11 patients (73%) (complete remission in seven and incomplete remission in one). Six of 11 patients (55%) then became steroid sensitive. Post-therapy biopsies, performed in 13 patients (10 with SDNS and three with SRNS), showed mild stripped interstitial fibrosis in two SDNS patients (15%). Long-term CsA therapy in moderate doses was effective to the patients with SDNS and SRNS and low in incidence of nephrotoxicity. The long-term use of CsA appears to result in a decrease in the proportion of SDNS and acquisition of subsequent steroid responsiveness in SRNS.