Impact of long-term treatment of methylphenidate on height and weight of school age children with ADHD

Stimulant-associated growth deficits in children with attention deficit hyperactivity disorder (ADHD) have long been a concern. We chose 146 school age children diagnosed with ADHD being treated with methylphenidate (MPH) and 29 drug-free ADHD children, and followed them up for 2-4 years. We recorded the changes in height and weight after long-term methylphenidate treatment and analyzed the influence of confounding factors to growth in height, weight, and height velocity. The change of the gap between patients' height and mean height in the methylphenidate group was -1.86+/-0.82 cm ( P<0.001); in controls it was -0.26+/-0.51 cm ( P<0.05). The changes of height standard deviation score (SDS) in the methylphenidate group and controls were -0.14+/-0.23 SD ( P<0.001) and +0.05+/-0.10 SD ( P<0.05), respectively. The differences between the 2 groups were significant ( P<0.001). Both correlation and regression analyses indicated that the duration of treatment contributed significantly to the variance in change of height ( P<0.001). The height velocity was significantly attenuated in the first year. The change of the gap between the patients' weight and weight for height after methylphenidate was -0.14+/-1.25 kg ( P>0.05). From this study, a small but significant deceleration of height velocity has been identified as a long-term side effect of methylphenidate, the magnitude of the height deficit is related to the duration of treatment. Methylphenidate had no significant influence on weight and BMI values.

Relationship of Anthracycline-Free Interval to Outcomes in a Phase 3 Trial of Pegylated Liposomal Doxorubicin Plus Docetaxel Compared with Docetaxel Monotherapy in Patients with Advanced Breast Cancer Treated with Adjuvant Anthracycline

Background: An earlier report showed that pegylated liposomal doxorubicin (PLD) + docetaxel (D) improved time to progression (TTP) vs D alone in patients (pts) with advanced breast cancer (ABC) who had relapsed at least 1 year after adjuvant or neoadjuvant anthracycline therapy. (Sparano et al., SABC 2008, #80) This analysis evaluated whether the time between completion of adjuvant anthracycline therapy until relapse impacts overall outcome. We retrospectively examined outcomes in pts with an anthracycline-free (A-F) interval of 1 to 2 years and pts with an A-F of &gt;2 years.Methods: 751 pts were randomly assigned to receive either D 75 mg/m2 (N=373) or PLD 30 mg/m2 followed by D 60 mg/m2 (N=378) every 21 days. Treatment was continued until disease progression or the occurrence of unacceptable toxicity. The primary endpoint was TTP and secondary endpoints included overall survival (OS), progression free survival (PFS), objective response rate (ORR), and safety. Pts were categorized into groups by anthracycline-free interval of 1-2 years or &gt;2 years. Relationship between the interval and outcomes was examined by proportional hazards model for TTP, OS (updated as of 1-Dec-2008), and PFS.Results: Approximately 60% of pts in both treatment groups had A-F intervals of &gt;2 years. Median TTP, OS, and PFS (months) by A-F interval groups are listed in the Table. A-F interval 1-2 years  A-F interval &gt;2 years   D, n=151PLD+D, n=155HR (CI)*; P**D, n=221PLD+D, n=221HR (CI)*; P**TTP5.77.80.67 (0.52, 0.87); .0027.710.60.63 (0.50, 0.79); &lt;.001OS15.817.90.90 (0.69, 1.16); .40424.722.91.10 (0.86, 1.40); .448PFS5.57.70.67 (0.52, 0.87); .0027.710.00.65 (0.51, 0.81); &lt;.001ORR25%34%P=.086†27%36%P=.042† A-F interval 1-2 years, N=306  A-F interval &gt;2 years, N=442 HR (CI)***; P**TTP6.6  8.9 0.74 (0.63, 0.88); .001OS17.2  23.4 0.63 (0.52, 0.75); &lt;.001PFS6.5  8.7 0.74 (0.62, 0.87); &lt;.001ORR30%  31% P=.826†*Proportional hazard model for PLD+D vs D; **Log-rank test; ***Proportional hazard model for &gt;2 years vs ≤2 years A-F; †Cochran-Mantel-Haenszel test.Overall, HFS and stomatitis occurred more often in pts treated with PLD+D. The overall incidence of CHF was 1%.Conclusions: An A-F interval of &gt;2 years reduced the risk for TTP, OS, and PFS, regardless of treatment. However, similar to results of the overall study, treatment with the combination PLD+D resulted in statistically significant improvement of TTP and PFS, but not OS, compared with D among pts with ABC, regardless of A-F interval. The addition of PLD to a D-based regimen is an active option for pts with ABC previously treated with adjuvant anthracycline regimens.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2095.

Risk factors of nosocomial infection with extended-spectrum beta-lactamase-producing bacteria in a neonatal intensive care unit in China

BACKGROUND

To study risk factors of neonatal nosocomial infection caused by extended-spectrum beta-lactamase (ESBL)-producing bacteria in a neonatal intensive care unit (NICU).

PATIENTS AND METHODS

A retrospective cohort study was conducted in a university hospital NICU in south China. Medical records of neonatal nosocomial infection caused by Escherichia coli or Klebsiella pneumoniae were reviewed. Twenty-two neonates infected with ESBL-producing bacteria (case patients) were compared with 17 patients infected with non-ESBL producing strains (controls). Univariable and multivariable logistic regression were performed to analyze risk factors for infection with ESBL-producing strains. The spectrum of antimicrobial resistance of ESBL-positive E. coli or K. pneumoniae was also examined.

RESULTS

Both univariable and multivariable logistic regression analysis revealed that preterm low birth weight, prolonged mechanical ventilation (> or = 7 days) and prior use of third-generation cephalosporins were risks factors for ESBL-producing E. coli or K. pneumoniae infection (p < 0.05), with an odd ratio of 6.43 (95% CI: 1.51-27.44; p = 0.017), 7.50 (95% CI: 1.38-40.88; p = 0.017) and 9.00 (95% CI: 1.65-49.14; p = 0.008) respectively. However, the length of hospital stay before isolation of pathogens, endotracheal intubation, presence of a central venous catheter, days on third-generation cephalosporins and prior use of beta-lactamase inhibitors were not statistically significant (p > 0.05). Resistance of ESBL-positive strains to piperacillin, tobramycin, aztreonam and cephalosporins was significantly higher than that of ESBL-negative ones (p < 0.05). ESBL-producing strains appeared susceptible to carbapenem, fluoroquinolones, and beta-lactamase inhibitor combination piperacillin-tazobactam.

CONCLUSIONS

Preterm low birth weight, prolonged mechanical ventilation and prior use of third-generation cephalosporins are risks factors for nosocomial infection with ESBL-producing bacteria in NICU.

Behaviorally relevant endocannabinoid action in hippocampus: dependence on temporal summation of multiple inputs

Endocannabinoids have been shown to mediate depolarization-induced suppression of GABAergic inhibition (DSI), possibly via release and retrograde diffusion following moderate to severe depolarization of hippocampal pyramidal neurons. However, it is not clear how hippocampal neurons, which have relatively low firing rates in vivo, achieve the degree of depolarization required to release endocannabinoids. Here it is demonstrated that DSI is not dependent on the occurrence of action potentials in the postsynaptic neuron, but is mediated by depolarization-induced calcium entry via voltage-controlled calcium channels (VCCs). The optimal level of calcium entry, and subsequent DSI, are directly related to the frequency of depolarizing pulses, which differs between immature and adult hippocampus. However, it is shown via modeled spike train inputs that the frequency dependence of DSI is overcome if two or more convergent spike trains from different neurons with normal in vivo firing rates converge and overlap in time. In these modeled circumstances, endocannabinoid-mediated DSI occurs most often when converging synaptic inputs from multiple neurons fire in synchrony to allow temporal summation of local membrane events in postsynaptic cells to exceed threshold for calcium entry. It is therefore possible that such suppression of inhibition would only occur during the time that recipient hippocampal neurons receive multiple coincident excitatory synaptic inputs.

A dominant form of congenital stationary night blindness (adCSNB) in a large Chinese family

Summary A pedigree of congenital stationary night blindness (CSNB) is described in a large Chinese family. The clinical description, pedigree, dark adaptation and elctroretinogram (ERG) studies indicate that the patients have an autosomal dominant form (ad) of CSNB. The disorder has been transmitted through at least 12 generations with over 40 affected individuals identified. The ERG data reveal that affected persons have severely diminished b-wave responses to dim light, but normal a-wave and subnormal b-wave responses to maximum light stimuli. The dark adaptation curves of three patients show a monophase curve, typical for night blindness. We have excluded the five previously known mutations in the three genes (RHO, PDE6B and GNAT1) associated with adCSNB, and linkage studies have excluded tight linkage between the disease locus and markers associated with these three genes. Thus, this family has adCSNB caused by a different gene from the previously identified RHO, PDE6B, and GNAT1.

Coumaroyl flavonol glycosides from the leaves of Ginkgo biloba

Two coumaroyl flavonol glycosides, isorhamnetin 3-O-alpha-L-[6"'-p-coumaroyl-(beta-D)-glucopyranosyl-(1,2)-rhamnopyranoside], and kaempferol 3-O-alpha-L-[6"'-p-coumaroyl-(beta-D)-glucopyranosyl-(1,2)-rhamnopyranoside]-7-O-beta-D-glucopyranoside, were isolated from the n-BuOH extract of Ginkgo biloba leaves. These two, together with six other flavonol glycosides, kaempferol 3-O-alpha-L-[6"'-p-coumaroyl-(beta-D)-glucopyranosyl-(1,2)-rhamnopyranoside], quercetin 3-O-alpha-L-[6"'-p-coumaroyl-(beta-D)-glucopyranosyl-(1,2)-rhamnopyranoside], quercetin 3-O-alpha-L-[6"'-p-coumaroyl-(beta-D)-glucopyranosyl-(1,2)-rhamnopyranoside]-7-O-beta-D-glucopyranoside, quercetin 3-O-beta-D-glucopyranosyl-(1-2)-alpha-L-rhamnopyranoside, quercetin 3-O-beta-rutinoside, and quercetin 3-O-beta-D-glucopyranoside, showed profound antioxidant activities in DPPH and cytochrome-c reduction assays using the HL-60 cell culture system.

Protein kinase C inhibits singlet oxygen-induced apoptosis by decreasing caspase-8 activation

Although activation of protein kinase C (PKC) inhibits apoptosis induced by a variety of stimuli including singlet oxygen, the step at which PKC activation interferes with apoptotic signaling is not well defined. We have shown previously that caspase-8 and p38 mediate singlet oxygen-induced apoptosis in HL-60 cells. In this study, we investigated the influence of PKC on regulation of the caspase and p38 pathways initiated by singlet oxygen. Singlet oxygen induced Fas clustering and subsequent recruitment of FADD and caspase-8. Treatment of cells with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA), a PKC activator, did not affect the binding of caspase-8 to the aggregated Fas. Surprisingly, under the same conditions PKC activation was still able to prevent singlet oxygen-induced activation of caspase-8 and block its downstream signaling events including cleavage of Bid and caspase-3, decrease in mitochondrial transmembrane potential and release of cytochrome c from mitochondria. Inhibition of PKC by GF109203 or H7 counteracted the TPA-mediated effects on the cleavage of caspases -3 and -8. However, neither activation nor inhibition of PKC affected p38 phosphorylation. These data indicate that PKC inhibits singlet oxygen-induced apoptosis by blocking activation of caspase-8.

Empty capsids in column-purified recombinant adenovirus preparations

Empty capsids from adenovirus, that is, virus particles lacking DNA, are well documented in the published literature. They can be separated from complete virus by CsCl density gradient centrifugation. Here we characterize the presence of empty capsids in recombinant adenovirus preparations purified by column chromatography. The initial purified recombinant adenovirus containing the p53 tumor suppressor gene was produced from 293 cells grown on microcarriers and purified by passage through DEAE-Fractogel and gel-filtration chromatography. Further sequential purification of the column-purified virus by CsCl and glycerol density gradient centrifugations yielded isolated complete virus and empty capsids. The empty capsids were essentially noninfectious and free of DNA. Analysis of empty capsids by SDS-PAGE or RP-HPLC showed the presence of only three major components: hexon, IIIa, and a 31K band. This last protein was identified as the precursor to protein VIII (pVIII) by mass spectrometric analysis. No pVIII was detected from the purified complete virus. Analysis by electron microscopy of the empty capsids showed particles with small defects. The amount of pVIII was used to determine the level of empty capsid contamination. First, the purified empty capsids were used to quantify the relation of pVIII to empty capsid particle concentration (as estimated by either light scattering or hexon content). They were then used as a standard to establish the empty capsid concentration of various recombinant adenovirus preparations. Preliminary research showed changes in empty capsid concentration with variations in the infection conditions. While virus purification on anion-exchange or gel-filtration chromatography has little effect on empty capsid contamination, other chromatographic steps can substantially reduce the final concentration of empty capsids in column-purified adenovirus preparations.

Selective AV nodal vagal stimulation improves hemodynamics during acute atrial fibrillation in dogs

Although the atrioventricular node (AVN) plays a vital role in blocking many of the atrial impulses from reaching the ventricles during atrial fibrillation (AF), a rapid irregular ventricular rate nevertheless persists. The goals of the present study were to explore the feasibility of novel epicardial selective vagal nerve stimulation for slowing of the ventricular rate during AF and to characterize the hemodynamic benefits in vivo. Electrophysiological-echocardiographic experiments were performed on 11 anesthetized open-chest dogs. Hemodynamic measurements were performed during three distinct periods: 1) sinus rate, 2) AF, and 3) AF with vagal nerve stimulation. AF was associated with significant deterioration of all measured parameters (P < 0.025). The vagal nerve stimulation produced slowing of the ventricular rate, significant reversal of the pressure and contractile indexes (P < 0.025), and a sharp reduction in one-half of the abortive ventricular contractions. The present study provides comprehensive evidence that slowing of the ventricular rate during AF by selective ganglionic stimulation of the vagal nerves that innervate the AVN successfully improved the hemodynamic responses.

His electrogram alternans reveal dual-wavefront inputs into and longitudinal dissociation within the bundle of His

BACKGROUND

His electrogram (HE) amplitude and morphology changes were observed in our previous studies during transition from "fast" to "slow" atrioventricular nodal (AVN) conduction. This phenomenon and its significance for the dual-AVN electrophysiology are not well recognized and have not been studied.

METHODS AND RESULTS

Experiments were performed on 17 healthy rabbit atrial-AVN preparations during standard programmed electrical pacing. HEs were mapped along the His bundle with roving surface electrodes, along with recording of cellular action potentials (APs). HEs recorded from the superior margin of the His bundle were of greater amplitude during basic beats and decreased substantially, by 42+/-19% (P<0.01), when premature A(1)A(2) shortened to 178+/-20 ms. In contrast, the HEs from the inferior margin increased dramatically, 2.9+/-1.7 times (P<0.01), during short A(1)A(2) and remained high until AVN block occurred. In addition, during long A(1)A(2), the superior HEs consistently preceded the inferior by 1.9+/-0.7 ms. In contrast, at short A(1)A(2), the superior HEs occurred 2.7+/-0.8 ms after the inferior. Cellular AP recordings demonstrated clearly the presence of and the transition between early (fast) and late (slow) excitation wavefronts that accompanied HE alternans.

CONCLUSIONS

The morphological-electrophysiological evidence from the AV junction suggests that fast and slow wavefronts reach the His bundle differently, producing functional longitudinal dissociation into 2 domains. The characteristic HE alternans recorded from these domains are a new sensitive tool to determine the presence of distinctly different wavefronts and their participation in the conduction during reentrant or other arrhythmias. These findings provide further understanding of the mechanisms of dual-AVN electrophysiology.

Four new isoflavone triglycosides from Sophora japonica

Four new isoflavone triglycosides, genistein 7-O-beta-D-glucopyranoside-4'-O-[(alpha-L-rhamnopyranosyl)-(1-->2)-beta-D-glucopyranoside] (1), genistein 7-O-beta-D-glucopyranoside-4'-O-[(beta-D-glucopyranosyl)-(1-->2)-beta-D-glucopyranoside] (2), genistein 7-O-alpha-L-rhamnopyranoside-4'-O-[(alpha-L-rhamnopyranosyl)-(1-->2)-beta-D-glucopyranoside] (3), and genistein 7-O-alpha-L-rhamnopyranoside-4'-O-[(beta-D-glucopyranosyl)-(1-->2)-beta-D-glucopyranoside] (4), together with nine known compounds, namely, genistein 7-O-beta-D-glucopyranoside-4'-O-beta-D-glucopyranoside, sophorabioside, prunetin 4'-O-beta-D-glucopyranoside, sophororicoside, genistin, rutin, kaempferol 3-O-beta-rutinoside, quercetin 3-O-beta-D-glucopyranoside, and kaempferol 3-O-beta-D-glucopyranoside, were isolated from the pericarps of Sophora japonica. The structures of 1-4 were determined by spectroscopic methods.

Assessment of LV systolic function in atrial fibrillation using an index of preceding cardiac cycles

The clinical assessment of left ventricular (LV) systolic function during atrial fibrillation (AF) is unreliable and difficult because of beat-to-beat variability. We evaluated an index for the estimation of LV systolic function in AF that is based on the relationship between the preceding (R-R1) and prepreceding (R-R2) R-R intervals. LV Doppler stroke volume (SV), ejection fraction (EF), peak aortic flow rate (AoF) and the maximum value of the first derivative of the LV pressure curve (dP/dt(max)) were evaluated in 13 healthy open-chest dogs during triggered AF. All parameters showed a significantly strong positive linear relationship with the ratio of R-R1/R-R2 (r = 0.65, 0.74, 0.75, and 0.70 for SV, EF, AoF, and dP/dt(max), respectively). The calculated value of LV systolic parameters at R-R1/R-R2 = 1 in the linear regression line showed a good relationship and an agreement with the measured average value of the parameter over all cardiac cycles (SV, 12.1 vs. 12.8 ml; EF, 49.6 vs. 51.2%; AoF, 1.37 vs. 1.48 l/min; and dP/dt(max), 2,323 vs. 2,454 mmHg/s). Using the LV systolic parameters estimated at R-R1/R-R2 = 1 in the linear regression line allows the LV contractile function to be accurately and reproducibly evaluated during AF and obviates the less-reliable process of averaging multiple cardiac cycles.

Differential effects of protein kinase C on human vascular smooth muscle cell proliferation and migration

Vascular smooth muscle cell (SMC) migration and proliferation contribute to intimal hyperplasia, and protein kinase C (PKC) may be required for both events. In this report, we investigated the role of PKC in proliferation and migration of SMC derived from the human saphenous vein. Activation of PKC by phorbol-12,13-dibutyrate (PDBu) or (-)-indolactam [(-)-ILV] increases SMC proliferation. Downregulation of PKC activity by prolonged incubation with phorbol ester or inhibition of PKC with chelerythrine in SMC diminished agonist-stimulated proliferation. In contrast, stimulation of PKC with PDBu or (-)-ILV inhibited basal and agonist-induced SMC chemotaxis. Moreover, downregulation of PKC or inhibition with chelerythrine accentuated migration. We postulated that the inhibitory effect of PKC on SMC chemotaxis was mediated through cAMP-dependent protein kinase (protein kinase A, PKA). In support of this hypothesis, we found that activation of PKC in SMC stimulated PKA activity. The cAMP agonist forskolin significantly inhibited SMC chemotaxis. Furthermore, the inhibitory effect of PKC on SMC chemotaxis was completely reversed by cAMP or PKA inhibitors. In search of the PKC isotype(s) underlying these differential effects of PKC in SMC, we identified eight isotypes expressed in human SMC. Only PKC-alpha, -beta I, -delta, and -epsilon were eliminated by downregulation, suggesting that one or more of these four enzymes facilitate the observed phorbol ester-dependent effects of PKC in SMC. In summary, we found that PKC activation enhances proliferation but inhibits migration of human vascular SMC. These differential effect of PKC on vascular cells appears to be mediated through PKC-alpha, -beta I, -delta, and/or -epsilon.

Cell type-specific regulation of B-Raf kinase by cAMP and 14-3-3 proteins

Cyclic AMP can either activate or inhibit the mitogen-activated protein kinase (MAPK) pathway in different cell types; MAPK activation has been observed in B-Raf-expressing cells and has been attributed to Rap1 activation with subsequent B-Raf activation, whereas MAPK inhibition has been observed in cells lacking B-Raf and has been attributed to cAMP-dependent protein kinase (protein kinase A)-mediated phosphorylation and inhibition of Raf-1 kinase. We found that cAMP stimulated MAPK activity in CHO-K1 and PC12 cells but inhibited MAPK activity in C6 and NB2A cells. In all four cell types, cAMP activated Rap1, and the 95- and 68-kDa isoforms of B-Raf were expressed. cAMP activation or inhibition of MAPK correlated with activation or inhibition of endogenous and transfected B-Raf kinase. Although all cell types expressed similar amounts of 14-3-3 proteins, approximately 5-fold less 14-3-3 was associated with B-Raf in cells in which cAMP was inhibitory than in cells in which cAMP was stimulatory. We found that the cell type-specific inhibition of B-Raf could be completely prevented by overexpression of 14-3-3 isoforms, whereas expression of a dominant negative 14-3-3 mutant resulted in partial loss of B-Raf activity. Our data suggest that 14-3-3 bound to B-Raf protects the enzyme from protein kinase A-mediated inhibition; the amount of 14-3-3 associated with B-Raf may explain the tissue-specific effects of cAMP on B-Raf kinase activity.

Singlet oxygen, but not oxidizing radicals, induces apoptosis in HL-60 cells

Oxidizing species (OS), produced by photosensitization or derived from cytotoxic agents, activate apoptotic pathways. We investigated whether two different OS, formed at the same subcellular sites, have equivalent ability to initiate apoptosis in HL-60 cells. Our previous work showed that absorption of visible light by rose bengal (RB) produces singlet oxygen exclusively, whereas absorption of ultraviolet A produces RB-derived radicals in addition to singlet oxygen. Singlet oxygen, but not the RB-derived radicals, induced nuclear condensation and DNA fragmentation into nucleosome-size fragments in a dose dependent manner. In contrast, the RB-derived radicals caused greater lipid oxidation than singlet oxygen. These results indicate that different OS, produced at the same subcellular sites, do not have the same ability to induce apoptosis and that the ability of an OS to initiate lipid oxidation does not necessarily correlate with its ability to induce apoptosis.

p38 mitogen-activated protein kinase mediates bid cleavage, mitochondrial dysfunction, and caspase-3 activation during apoptosis induced by singlet oxygen but not by hydrogen peroxide

p38 mitogen-activated protein kinase is activated and involved in cleavage of caspase-3 during apoptosis induced by a number of stimuli. However, the signaling events triggered by p38 that result in caspase-3 activation are still unknown. In human leukemia cells, two reactive oxygen species, singlet oxygen and hydrogen peroxide (H(2)O(2)), selectively stimulated the phosphorylation of p38. Preincubation of cells with SB203580, a specific inhibitor of p38, dose dependently inhibited DNA fragmentation induced by singlet oxygen but not by H(2)O(2). Protection from apoptosis by SB203580 correlated with inhibition of caspase-3, and several events that are associated with caspase-3 activation, including Bid cleavage, decrease in mitochondrial transmembrane potential and release of cytochrome c from mitochondria, whereas caspase-8 cleavage was not affected by this inhibitor. In contrast, blockade of caspase-8 with Ile-Glu-Thr-Asp-fluoromethyl ketone is sufficient to prevent formation of DNA fragments and to inhibit all the above signaling events, with exception of p38 phosphorylation, in both singlet oxygen- and H(2)O(2)-treated cells. These data suggest that caspase-3 activation is regulated through redundant signaling pathways that involve p38 and caspase-8 acting upstream of Bid during singlet oxygen-induced apoptosis, whereas the activation of caspase-3 by H(2)O(2) is only governed by a caspase-8-mediated apoptotic pathway.

Peroxynitrite-induced apoptosis involves activation of multiple caspases in HL-60 cells

In this study, we show that caspases 2, 3, 6, and 7 were activated during peroxynitrite-induced apoptosis in human leukemia HL-60 cells and that processing of these caspases was accompanied by cleavage of poly(ADP-ribose) polymerase and lamin B. Treatment of cells with DEVD-fluoromethyl ketone (FMK), a selective inhibitor for caspase 3-like proteases, resulted in a marked diminution of apoptotic cells. VAVAD-FMK, an inhibitor of caspase 2, partially inhibited the apoptotic response to peroxynitrite. However, selective inactivation of caspase 6 by VEID-FMK did not affect apoptosis rates. These data suggest that caspase 3-like proteases and caspase 2, but not caspase 6, are required for peroxynitrite-induced apoptosis in this cell type. Moreover, we demonstrate that peroxynitrite treatment stimulated activation of caspases 8 and 9, two initial caspases in the apoptotic signaling pathway, and preincubation of cells with their inhibitor, IETD-FMK, inhibited activation of caspase 3-like proteases and caspase 2 at the concentration that prevents the apoptosis. These observations, together, suggest that caspase 8 and/or caspase 9 mediates activation of caspase 3-like proteases and caspase 2 during the apoptosis induced by peroxynitrite in HL-60 cells.

Genetic analysis of Raf1, Mdm2, c-Myc, Cdc25a and Cdc25b proto-oncogenes in 2',3'-dideoxycytidine- and 1,3-butadiene-induced lymphomas in B6C3F1 mice

We have previously identified activation of ras proto-oncogenes and inactivation of tumor suppressor genes including p53, p16(INK4a) and p15(INK4b) in 2',3'-dideoxycytidine (ddC)- and/or 1,3-butadiene (BD)-induced lymphomas derived from B6C3F1 (C57BL/6xC3H/He) mice, indicating that alterations of ras signaling pathway, p53 and pRb growth control pathways are important in the development of these chemically induced lymphomas. However, there is still a subset of tumors that displayed no changes in these genes. Thus, we investigated whether the Raf1, Mdm2, c-Myc, Cdc25a and Cdc25b proto-oncogenes, which are implicated in the ras or p53 or pRb pathways, are alternative oncogenic target genes. Analyses of gross genomic alterations by Southern blots failed to reveal rearrangement or amplification in any of the tumors examined. Frequent point mutations on the substrate binding domain of the Raf1 gene has been reported in 1-ethyl-1-nitrosourea (ENU)-induced murine lymphomas and lung tumors, along with a conspicuous lack of ras mutations [U. Naumann, I. Eisenmann-Tappe, U.R. Rapp, The role of raf kinases in development and growth of tumors, Recent Results Cancer Res., 143 (1997) 237-244]. To investigate whether Raf1 mutation is involved in our set of tumor especially those without ras mutations, the PCR-based single-strand conformation analyses (SSCA) and direct DNA sequencing were employed. No mutations but four genetic polymorphisms between C57BL/6 and C3H/He were found, with two of them reported as point mutations previously (op. cit.). The polymorphisms were utilized for allelic loss study of Raf1 locus. Losses of heterozygosity were found in six of 31 BD-induced lymphomas. These results indicate that genetic alterations of c-Myc, Cdc25, Raf1 and Mdm2 proto-oncogenes may not be involved in the development of ddC- and BD-induced lymphomas and the inactivation of tumor suppressor gene(s) located close to Raf1 gene might be important in the development of a subset of BD-induced lymphomas.

The major myosin-binding site of caldesmon resides near its N-terminal extreme

The primary myosin-binding site of caldesmon was thought to be in the N-terminal region of the molecule, but the exact nature of the caldesmon-myosin interaction has not been well characterized. A caldesmon fragment that encompasses residues 1-240 (N240) was found to bind full-length smooth muscle myosin on the basis of co-sedimentation experiments. The interaction between myosin and N240 was not affected by phosphorylation of myosin, but it was weakened by the presence of Ca(2+)/calmodulin. To locate the myosin-binding site, we have designed several synthetic peptides based on the N-terminal caldesmon sequence. We found that a peptide stretch corresponding to the first 27 residues (Met-1 to Tyr-27), but not that of the first 22 residues (Met-1 to Ala-22), exhibited a moderate affinity toward myosin. We also found that a peptide containing the segment from Ile/Leu-25 to Lys-53 bound both myosin and heavy meromyosin more strongly and was capable of displacing caldesmon from myosin. Our results demonstrate that the sequence near the N-terminal extreme of caldesmon harbors a major myosin-binding site of caldesmon, in which both the nonpolar residues and clusters of positively and negatively charged residues confer the specificity and affinity of the caldesmon-myosin interaction.

Hyperosmolality induces activation of cPKC and nPKC, a requirement for ERK1/2 activation in NIH/3T3 cells

Protein kinase C (PKC) has been reported to be associated with the activation of extracellular signal-regulated kinase (ERK) by hyperosmolality. However, it is unclear whether hyperosmolality induces PKC activation and which PKC isoforms are involved in ERK activation. In this study, we demonstrate that NaCl increases total PKC activity and induces PKCalpha, PKCdelta, and PKCepsilon translocation from the cytosol to the membrane in NIH/3T3 cells, suggesting that hyperosmotic stress activates conventional PKC (cPKC) and novel PKC (nPKC). Further studies show that NaCl-inducible ERK1 and ERK2 (ERK1/2) activation is a consequence of cPKC and nPKC activation, because either downregulation with 12-O-tetradecanoylphorbol 13-acetate or selective inhibition of cPKC and nPKC by GF-109203X and rottlerin largely inhibited the stimulation of ERK1/2 phosphorylation by NaCl. In addition, we show that NaCl increases diacylglycerol (DAG) levels and that a phospholipase C (PLC) inhibitor, U-73122, inhibits NaCl-induced ERK1/2 phosphorylation. These results, together, suggest that a hyperosmotic NaCl-induced signaling pathway that leads to activation of ERK1/2 may sequentially involve PLC activation, DAG release, and cPKC and nPKC activation.

Intra-articular IL-4 gene therapy in arthritis: anti-inflammatory effect and enhanced th2activity

Gene therapy has been explored as a potential method for treating chronic inflammatory diseases such as rheumatoid arthritis. To determine the efficacy of intra-articular IL-4 gene therapy in an animal model of arthritis using a retroviral vector, a retrovirus encoding rat IL-4 (DA-IL-4) was engineered, purified and concentrated to high titer (>/=109 CFU/ml). Infectivity and expression levels were demonstrated in vitro using cultured fibroblast-like synoviocytes. Efficacy was evaluated in the rat adjuvant arthritis model. DA-IL-4 or DA-beta-gal retrovirus was injected into the intra-articular joint space of the right ankle on day 12 after immunization. Three days after joint injection, the injected paw contained increased levels of IL-4 compared with control or with the contralateral uninjected paw, demonstrating successful transgene expression. Surprisingly, 8 days after treatment IL-4 levels continued to increase in the injected and contralateral paw compared with DA-beta-gal-treated animals. Serum IL-4 levels were also elevated in DA-IL-4-treated rats. RT-PCR studies demonstrated that the transgene was expressed in the injected ankle but not in the contralateral joint. IL-4 gene therapy resulted in a significant reduction in paw swelling and decreased radiographic evidence of bone destruction. This is the first demonstration of successful intra-articular retroviral gene treatment using a therapeutic gene. In addition to its anti-inflammatory effect, this study supports the potential application of intra-articular gene therapy as a method for enhancing systemic Th2 function.

Caspase-8 mediates caspase-3 activation and cytochrome c release during singlet oxygen-induced apoptosis of HL-60 cells

We reported previously that singlet oxygen, generated by irradiation of rose bengal with visible light, induced apoptosis in human promyelocytic leukemia HL-60 cells. However, the mechanism of apoptosis caused by this reactive oxygen species is unclear. In this study, we demonstrate that singlet oxygen induced caspase-3 activation and Z-DEVD-FMK, a caspase-3 inhibitor, blocked apoptosis induction, while caspase-1 activity was not detectable and the caspase-1 inhibitor Z-YVAD-FMK had a very limited effect on apoptosis. This suggests that the activation of caspase-3 by singlet oxygen is essential for the commitment of cells to undergo apoptosis. Further studies showed that singlet oxygen induced an increase in caspase-8 activity and a reduction in mitochondrial cytochrome c. Time course analysis indicated that the cleavage of caspase-8 precedes that of caspase-3. In addition, blockade of caspase-8 by Z-IETD-FMK inhibited cleavage of pro-caspase-3 and prevented loss of mitochondrial cytochrome c. These results suggest that caspase-8 mediates caspase-3 activation and cytochrome c release during singlet oxygen-induced apoptosis in HL-60 cells.

p53 overexpression in synovial tissue from patients with early and longstanding rheumatoid arthritis compared with patients with reactive arthritis and osteoarthritis

OBJECTIVE

The p53 tumor suppressor gene is overexpressed in synovial tissue (ST) from patients with longstanding rheumatoid arthritis (RA), and may contain somatic mutations. The aim of this study was to determine p53 expression in ST from RA patients in different stages of the disease, compared with disease controls.

METHODS

ST biopsy specimens were obtained from the knee joints of 31 RA patients in varying disease phases, 8 patients with reactive arthritis (ReA), 10 patients with inflammatory osteoarthritis (OA), and 6 control patients (4 with meniscus pathology, 2 with vascular insufficiency). ST was also obtained from the clinically uninvolved knee joints of 9 RA patients. Expression of p53 was determined by immunohistology with DO1 monoclonal antibody (mAb) in all patients and by Western blot analysis with DO7 mAb in a subgroup of the patients.

RESULTS

The p53 protein was detected by immunohistology in 10 of the 13 patients with early RA (duration <6 months) and in 12 of the 14 patients with longstanding RA (duration >5 years). The p53 protein was also demonstrated in clinically uninvolved knee joints. Western blots revealed immunoreactive p53 in ST extracts from all RA patients. Expression of p53 was about twice as high in ST from patients with longstanding RA as in early RA samples, but the difference did not reach statistical significance. Small amounts of p53 were also detected in ST from ReA and OA patients, although the expression in RA synovium was significantly higher. Immunohistologic analysis of normal ST gave negative results for p53.

CONCLUSION

This study shows that p53 overexpression is specific for RA, compared with OA and ReA. This phenomenon is probably secondary to increased production of wild-type p53 protein in response to DNA damage and secondary to somatic mutations caused by the genotoxic local environment in inflamed ST. Of interest, p53 overexpression can also be found in the earliest stages of RA and in clinically uninvolved joints.

Effects of long-term exposure to delta9-THC on expression of cannabinoid receptor (CB1) mRNA in different rat brain regions

The time course of changes across 21 days of continuous exposure to Delta9-tetrahydrocannabinol (Delta9-THC) was assessed for the level of cannabinoid receptor (CB1) mRNA expression in three different rat brain regions: cerebellum, hippocampus and corpus striatum. Expression levels of CB1 mRNA were determined using semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) following a protocol which included a gene standard, 28S ribonucleic acid protein (rRNA), for normalization of levels of RNA in the three different brain regions. The levels of CB1 mRNA were assessed in four different rats at each of seven time points (6 h, and 1, 2, 3, 7, 14 and 21 days) during a 21-day Delta9-THC one dose day-1 (10 mg kg-1) treatment regimen. In the cerebellum and hippocampus, CB1 mRNA levels were increased above vehicle control animals at 7 and 14 days of treatment. In the striatum the levels of CB1 transcripts were severely reduced from days 2-14. CB1 message expression in all three brain areas returned to vehicle control levels by day 21 of Delta9-THC treatment, a time at which behavioral tolerance has been previously reported. An additional measure, receptor stimulated GTPgammaS binding, performed over the same time period revealed differential desensitization within the 3 brain areas as a function of chronic exposure to Delta9-THC. Hippocampus was the earliest to desensitize decreasing to 35% of control by treatment day 7, followed by a decrease in the cerebellum to that same level on day 14 of treatment. The striatum showed only half that degree of desensitization (65%) over the entire 21-day treatment period. Comparisons suggests that CB1 message may be regulated by different effector systems in each of the three areas during chronic Delta9-THC exposure.

Activation of protein kinase C is required for protection of cells against apoptosis induced by singlet oxygen

We evaluated the role of protein kinase C (PKC) in the regulation of apoptosis triggered by singlet oxygen. Activation of PKC by short-term 12-O-tetradecanoyl phorbol 13-acetate (TPA) treatment inhibited apoptosis, whereas inhibition of PKC with several inhibitors potentiated this process. The antiapoptotic effect of TPA was accompanied by phosphorylation of extracelluar signal-regulated kinase 1/2 (ERK1/2). Pretreatment of cells with MEK inhibitor, PD98059, inhibited TPA-induced phosphorylation of ERK1/2 and the cytoprotective ability of TPA. These results suggest that activation of PKC in HL-60 cells confers protection against apoptosis induced by singlet oxygen and that ERK1/2 mediates antiapoptotic signaling of PKC.

[Studies on optimal conditions for inulinase production by Kluyveromyces sp. Y-85]

The application of response surface method to optimal medium-screeing for inulinase production by Kluyveromyces sp. Y-85 has been investigated. The experiments of condition control for the enzyme production was carried out in a 15 L fermenter. A large scale fermentation (1000 L fermenter) was performed five batches, and average inulinase activity of 68.9 u/ml achieved.

Transcatheter endomyocardial laser revascularization: a feasibility test

By means of a special catheter system, a total of 76 endomyocardial laser channels were percutaneously produced in a controllable manner at selected sites in 6 beating canine hearts. Acute patency of channels (length = 4-11 mm, diameter = 0.5-1.2 mm) was documented angioscopically and histologically. This minimally invasive method might be useful for revascularising certain patients with ischemic heart disease without resorting to open-chest surgery.

Calmodulin binds to caldesmon in an antiparallel manner

Two of the five tryptophan residues (W659 and W692) in chicken gizzard smooth muscle caldesmon (CaD) are located within the calmodulin (CaM) binding sites in the C-terminal region of the molecule. When these Trp residues are replaced with Gly in either recombinant fragments or synthetic peptides of CaD, the affinity for CaM is decreased by at least 10-fold, suggesting that both of these residues are important for the interaction of CaD with CaM. To gain information about the topography of the CaM-CaD complex, we have carried out fluorescence titrations of CaM with Tb3+ as a substitute for Ca2+ in the presence of wild-type or mutated CaD variants. By exciting Trp residues of CaD fragments or peptides while monitoring the enhanced luminescence of CaM-bound Tb3+ ions via resonance energy transfer, we were able to estimate the relative proximity between the bound metal ions in the two domains of CaM and the Trp residues of CaD. Our results suggest that in the CaM-CaD complex the metal-binding sites III and IV in the C-terminal domain of CaM are very close to W659 of CaD; the N-terminal domain of CaM appears associated with the region of CaD in the vicinity of W692, although sites I and II are relatively far away from this Trp residue. These findings are consistent with a model in which CaM binds to CaD in an antiparallel manner. Such a binding mode, however, may be flexible enough to accommodate alternative spatial arrangements when the preferred binding sites are either altered or rendered unavailable.

Involvement of protein kinase C in the activation of extracellular signal-regulated kinase 1/2 by UVC irradiation

UVC irradiation activates mitogen-activated protein kinases (MAPKs), including ERK, JNK, and P38. This study examined the role of protein kinase C (PKC) in the regulation of UVC-stimulated MAPKs activation. Either the depletion of PKC by prolonged treatment of cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) or the inhibition of PKC by a selective PKC inhibitor, UCN-01-ME, attenuated UVC-activation of ERK1/2, keeping the activation of JNK1/2 intact. However, K252a, a non-selective PKC inhibitor, inhibited the activation of both ERK1/2 and JNK1/2 by UVC. In three isoforms of PKC (alpha, delta, epsilon) examined, PKC epsilon shows the most evident translocation, a temporal association with cell membrane, upon the UVC irradiation of NIH 3T3 cells. These results suggest that PKC is acting in the UVC-dependent activation of ERK1/2, and PKC epsilon is one of the PKC isozymes playing such a role.

Apoptin induces apoptosis in human transformed and malignant cells but not in normal cells

The chicken anemia virus protein apoptin induces a p53-independent, Bcl-2-insensitive type of apoptosis in various human tumor cells. Here, we show that, in vitro, apoptin fails to induce programmed cell death in normal lymphoid, dermal, epidermal, endothelial, and smooth-muscle cells. However, when normal cells are transformed they become susceptible to apoptosis by apoptin. Long-term expression of apoptin in normal human fibroblasts revealed that apoptin has no toxic or transforming activity in these cells. In normal cells, apoptin was found predominantly in the cytoplasm, whereas in transformed and malignant cells it was located in the nucleus, suggesting that the localization of apoptin is related to its activity. These properties make apoptin a potential agent for the treatment of a large number of tumors, also those lacking p53 and/or overexpressing Bcl-2.

Heat treatment could affect the biochemical properties of caldesmon

Smooth muscle caldesmon (CaD) exhibits apparent heat stability. A widely used purification procedure of CaD involves extensive heat treatment (Bretscher, A. (1984) J. Biol. Chem. 259, 12873-12880). CaD thus purified co-sediments with actin, inhibits actomyosin ATPase activity, and interacts with Ca2+/calmodulin, similarly to the unheated protein. On the other hand, heat-treated CaD binds to actin filaments in a tether-like fashion, whereas lengthwise binding dominates in vivo (Mabuchi, K., Lin, J. J.-C., and Wang, C.-L. A. (1993) J. Muscle Res. Cell Motil. 14, 54-64), suggesting that differences do exist between heat-purified CaD and the native protein. We have isolated, without heat treatment, full-length recombinant chicken gizzard CaD overexpressed in insect cells (High-FiveTM) using a baculovirus expression system. We found that such unheated CaD interacts with calmodulin 10 times stronger than does the heated CaD; its inhibitory action on actomyosin ATPase is reversed by a much lesser amount of calmodulin. Moreover, electron microscopic examination indicated that actin binding at the N-terminal region is more frequent in the unheated CaD, resulting in more lengthwise binding. These findings point to the fact that CaD is not entirely heat-stable; the C-terminal CaM-binding regions and the N-terminal actin-binding region are possibly affected by heat treatment.

Identification of the functionally relevant calmodulin binding site in smooth muscle caldesmon

The C-terminal region of smooth muscle caldesmon (CaD) interacts with calmodulin (CaM) and reverses CaD's inhibitory effect on the actomyosin ATPase activity. We have previously shown that the major CaM-binding site (site A) in this region is within the segment from Met-658 to Ser-666 (Zhan, Q., Wong, S. S., and Wang, C.-L. A. (1991) J. Biol. Chem. 266, 21810-21814). Recently, another segment (site B), Asn-675 to Lys-695, was reported to bind CaM (Mezgueldi, M., Derancourt, J., Calas, B., Kassab, R., and Fattoum, A. (1994) J. Biol. Chem. 269, 12824-12832). To assess the functional relevance of these two putative CaM-binding sites, we have examined three synthetic peptides regarding their effects on CaM's ability to reverse CaD-induced inhibition of actomyosin ATPase activity: GS17C (Gly-651 to Ser-667), VG29C (Val-685 to Gly-713), each containing one CaM-binding site, and MG56C (Met-658 to Gly-713), which contains both sites. We found that although VG29C did bind CaM, its affinity was weakened by GS17C, and it failed to compete with CaD for CaM under the conditions where GS17C effectively displaced CaD from CaM. MG56C had an effect similar to that of GS17C. These experiments demonstrated that site A for CaM binding is involved in regulating the inhibitory property of CaD.

Interaction between caltropin and the C-terminal region of smooth muscle caldesmon

Caltropin (CaT) binds caldesmon (CaD) in a Ca(2+)-dependent manner with an affinity higher than that of calmodulin (CaM). Photo-crosslinking between CaT and a benzophenone-labeled C-terminal CaD fragment (27K) results in a 35-kDa protein that corresponds to the 1:1 adduct between CaT and 27K. In the absence of Ca2+, no crosslinking is obtained. This result is similar to that obtained with CaM and 27K. The apparent affinity of CaM for GS17C, a CaM-binding peptide of CaD, is weakened by CaT, suggesting CaT competes with CaM for the peptide. In contrast to CaM, CaT does not induce changes in the tryptophan fluorescence of GS17C. Thus although the two Ca(2+)-binding proteins behave similarly, there are differences in their interactions with CaD.