Mode stabilization in quantum cascade lasers via an intra-cavity cascaded nonlinearity.

We present self-stabilization of the inter-mode separation of a quantum cascade laser (QCL) emitting at 9 µm via cascaded second order nonlinearity. This effect has been observed in lasers that have the optical cavity embedded into a microwave strip-line. The intermodal beat note spectra narrow with increasing laser output power, up to less than 100 kHz. A flat frequency response to direct modulation up to 14 GHz is reported for these microstrip QCLs. The laser inter-mode spacing can be locked to an external RF signal and tuned by more than 1 MHz from the free-running spacing. A parallel study on the same laser material in a non-microstrip line waveguide shows superior performances of the microstrip QCL in terms of the intermodal spectral locking and stability. Finally by analyzing our results with the theory of the injection locking of coupled oscillators, we deduce that the microwave power injected in the microstrip QCL is 2 orders of magnitude higher than in the reference laser.

An assessment of the relationship between the World Health Organization HIV drug resistance early warning indicators and HIV drug resistance acquisition.

OBJECTIVES: The World Health Organization (WHO)'s HIV drug resistance (HIVDR) early warning indicators (EWIs) measure antiretroviral therapy (ART)-site factors associated with HIVDR prevention, without HIVDR laboratory testing. We assessed the relationship between EWIs and HIVDR acquisition using data from British Columbia, Canada. METHODS: Eligible patients were ART-naïve, were ≥ 19 years old, had initiated ART between 1 January 2000 and 31 December 2012, had ≥ 15 months of follow-up, and were without transmitted HIVDR. Patients were followed for acquired HIVDR until 31 March 2014, the last contact date, or death. We built logistic regression models to assess the associations and predictive ability of individual indicators and of the EWI Score (the number of indicators for which a patient did not meet the criteria) on HIVDR acquisition (to any class of HIVDR, lamivudine (3TC)/emtricitabine (FTC), nonnucleoside reverse transcriptase inhibitors (NNRTIs), nucleoside reverse transcriptase inhibitors (NRTIs) or protease inhibitors (PIs)]). RESULTS: All explored EWIs were associated with at least one class of HIVDR, with the exception of 'ART prescribing practices'. We observed a dose-response relationship between acquiring HIVDR to any antiretroviral class and an increasing EWI score in our predictive logistic regression model. The area under the curve was 0.848 (excellent discrimination). The adjusted odds ratios for acquiring any class of HIVDR for an EWI score of 1, 2 and ≥ 3 versus 0 were 2.30 [95% confidence Interval (CI) 1.21-4.38], 3.35 (95% CI: 1.86-6.03) and 7.26 (95% CI: 4.18-12.61), respectively. CONCLUSIONS: Several EWIs were associated with and predictive of HIVDR, supporting the WHO EWIs as a component of the HIVDR prevention method in settings where HIVDR testing is not routinely or widely available.

Exhaust ventilation in attached garages improves residential indoor air quality.

Previous research has shown that indoor benzene levels in homes with attached garages are higher than homes without attached garages. Exhaust ventilation in attached garages is one possible intervention to reduce these concentrations. To evaluate the effectiveness of this intervention, a randomized crossover study was conducted in 33 Ottawa homes in winter 2014. VOCs including benzene, toluene, ethylbenzene, and xylenes, nitrogen dioxide, carbon monoxide, and air exchange rates were measured over four 48-hour periods when a garage exhaust fan was turned on or off. A blower door test conducted in each garage was used to determine the required exhaust fan flow rate to provide a depressurization of 5 Pa in each garage relative to the home. When corrected for ambient concentrations, the fan decreased geometric mean indoor benzene concentrations from 1.04 to 0.40 µg/m3 , or by 62% (P<.05). The garage exhaust fan also significantly reduced outdoor-corrected geometric mean indoor concentrations of other pollutants, including toluene (53%), ethylbenzene (47%), m,p-xylene (45%), o-xylene (43%), and carbon monoxide (23%) (P<.05) while having no impact on the home air exchange rate. This study provides evidence that mechanical exhaust ventilation in attached garages can reduce indoor concentrations of pollutants originating from within attached garages.

Can changing the timing of outdoor air intake reduce indoor concentrations of traffic-related pollutants in schools?

Traffic emissions have been associated with a wide range of adverse health effects. Many schools are situated close to major roads, and as children spend much of their day in school, methods to reduce traffic-related air pollutant concentrations in the school environment are warranted. One promising method to reduce pollutant concentrations in schools is to alter the timing of the ventilation so that high ventilation time periods do not correspond to rush hour traffic. Health Canada, in collaboration with the Ottawa-Carleton District School Board, tested the effect of this action by collecting traffic-related air pollution data from four schools in Ottawa, Canada, during October and November 2013. A baseline and intervention period was assessed in each school. There were statistically significant (P < 0.05) reductions in concentrations of most of the pollutants measured at the two late-start (9 AM start) schools, after adjusting for outdoor concentrations and the absolute indoor-outdoor temperature difference. The intervention at the early-start (8 AM start) schools did not have significant reductions in pollutant concentrations. Based on these findings, changing the timing of the ventilation may be a cost-effective mechanism of reducing traffic-related pollutants in late-start schools located near major roads.

Optical sideband generation up to room temperature with mid-infrared quantum cascade lasers.

Mid-infrared (MIR) sideband generation on a near infrared (NIR) optical carrier is demonstrated within a quantum cascade laser (QCL). By employing an externally injected NIR beam, E(NIR), that is resonant with the interband transitions of the quantum wells in the QCL, the nonlinear susceptibility is enhanced, leading to both frequency mixing and sideband generation. A GaAs-based MIR QCL (E(QCL) = 135 meV) with an aluminum-reinforced waveguide was utilized to overlap the NIR and MIR modes with the optical nonlinearity of the active region. The resulting difference sideband (E(NIR) - E(QCL)) shows a resonant behavior as a function of NIR pump wavelength and a maximum second order nonlinear susceptibility, χ((2)), of ~1 nm/V was obtained. Further, the sideband intensity showed little dependence with the operating temperature of the QCL, allowing sideband generation to be realized at room temperature.

A randomized double-blind crossover study of indoor air filtration and acute changes in cardiorespiratory health in a First Nations community.

UNLABELLED: Few studies have examined indoor air quality in First Nations communities and its impact on cardiorespiratory health. To address this need, we conducted a crossover study on a First Nations reserve in Manitoba, Canada, including 37 residents in 20 homes. Each home received an electrostatic air filter and a placebo filter for 1 week in random order, and lung function, blood pressure, and endothelial function measures were collected at the beginning and end of each week. Indoor air pollutants were monitored throughout the study period. Indoor PM2.5 decreased substantially during air filter weeks relative to placebo (mean difference: 37 µg/m(3) , 95% CI: 10, 64) but remained approximately five times greater than outdoor concentrations owing to a high prevalence of indoor smoking. On average, air filter use was associated with a 217-ml (95% CI: 23, 410) increase in forced expiratory volume in 1 s, a 7.9-mm Hg (95% CI: -17, 0.82) decrease in systolic blood pressure, and a 4.5-mm Hg (95% CI: -11, 2.4) decrease in diastolic blood pressure. Consistent inverse associations were also observed between indoor PM2.5 and lung function. In general, our findings suggest that reducing indoor PM2.5 may contribute to improved lung function in First Nations communities. PRACTICAL IMPLICATIONS: Indoor air quality is known to contribute to adverse cardiorespiratory health, but few studies have examined indoor air quality in First Nations communities. Our findings suggest that indoor PM2.5 may contribute to reduced lung function and that portable air filters may help to alleviate these effects by effectively reducing indoor levels of particulate matter.

Charge-induced coherence between intersubband plasmons in a quantum structure.

In this Letter we investigate a low dimensional semiconductor system, in which the light-matter interaction is enhanced by the cooperative behavior of a large number of dipolar oscillators, at different frequencies, mutually phase locked by Coulomb interaction. We experimentally and theoretically demonstrate that, owing to this phenomenon, the optical response of a semiconductor quantum well with several occupied subbands is a single sharp resonance, associated with the excitation of a bright multisubband plasmon. This effect illustrates how the whole oscillator strength of a two-dimensional system can be concentrated into a single resonance independently from the shape of the confining potential. When this cooperative excitation is tuned in resonance with a cavity mode, their coupling strength can be increased monotonically with the electronic density, allowing the achievement of the ultrastrong coupling regime up to room temperature.

SMG1 and NIK regulate apoptosis induced by Smac mimetic compounds.

Smac mimetic compounds (SMCs) are experimental small molecules that induce tumour necrosis factor alpha (TNFα)-dependent cancer cell death by targeting the inhibitor of apoptosis proteins. However, many cancer cell lines are resistant to SMC-mediated apoptosis despite the presence of TNFα. To add insight into the mechanism of SMC-resistance, we used functional siRNA-based kinomic and focused chemical screens and identified suppressor of morphogenesis in genitalia-1 (SMG1) and NF-κB-inducing kinase (NIK) as novel protective factors. Both SMG1 and NIK prevent SMC-mediated apoptosis likely by maintaining FLICE inhibitory protein (c-FLIP) levels to suppress caspase-8 activation. In SMC-resistant cells, the accumulation of NIK upon SMC treatment enhanced the activity of both the classical and alternative nuclear factor-κB pathways, and increased c-FLIP mRNA levels. In parallel, persistent SMG1 expression in SMC-resistant cells repressed SMC-mediated TNFα-induced JNK activation and c-FLIP levels were sustained. Importantly, SMC-resistance is overcome by depleting NIK and SMG1, which appear to facilitate the downregulation of c-FLIP in response to SMC and TNFα treatment, leading to caspase-8-dependent apoptosis. Collectively, these data show that SMG1 and NIK function as critical repressors of SMC-mediated apoptosis by potentially converging on the regulation of c-FLIP metabolism.

Method validation and preliminary qualification of pharmacodynamic biomarkers employed to evaluate the clinical efficacy of an antisense compound (AEG35156) targeted to the X-linked inhibitor of apoptosis protein XIAP.

Data are presented on pharmacodynamic (PD) method validation and preliminary clinical qualification of three PD biomarker assays. M65 Elisa, which quantitates different forms of circulating cytokeratin 18 (CK18) as putative surrogate markers of both apoptotic and nonapoptotic tumour cell death, was shown to be highly reproducible: calibration curve linearity r2 = 0.996, mean accuracy > 91% and mean precision < 3%, n = 27. Employing recombinant (r) CK18 and caspase cleaved CK18 (CK18 Asp396 neo-epitope) as external standards, kit to kit reproducibly was < 6% (n = 19). rCK18 was stable in plasma for 4 months at -20 degrees C and -80 degrees C, for 4 weeks at 4 degrees C and had a half-life of 2.3 days at 37 degrees C. Cytokeratin 18 Asp396 NE, the M30 Apoptosense Elisa assay antigen, was stable in plasma for 6 months at -20 degrees C and -80 degrees C, for 3 months at 4 degrees C, while its half-life at 37 degrees C was 3.8 days. Within-day variations in endogenous plasma concentrations of the M30 and M65 antigens were assessed in two predose blood samples collected from a cohort of 15 ovarian cancer patients receiving carboplatin chemotherapy and were shown to be no greater than the variability associated with methods themselves. Between-day fluctuations in circulating levels of the M30 and M65 antigens and in XIAP mRNA levels measured in peripheral blood mononuclear cells by quantitative (q) RT-PCR were evaluated in two predose blood samples collected with a 5- to 7-day gap from 23 patients with advanced cancer enrolled in a phase I trial. The mean variation between the two pretreatment values ranged from 13 to 14 to 25%, respectively, for M65, M30 and qRT-PCR. These data suggest that the M30 and M65 Elisa's and qRT-PCR as PD biomarker assays have favourable performance characteristics for further investigation in clinical trials of anticancer agents which induce tumour apoptosis/necrosis or knockdown of the anti-apoptotic protein XIAP.

Validation of pharmacodynamic assays to evaluate the clinical efficacy of an antisense compound (AEG 35156) targeted to the X-linked inhibitor of apoptosis protein XIAP.

The inhibitor of apoptosis protein, XIAP, is frequently overexpressed in chemoresistant human tumours. An antisense oligonucleotide (AEG 35156/GEM 640) that targets XIAP has recently entered phase I trials in the UK. Method validation data are presented on three pharmacodynamic assays that will be utilised during this trial. Quantitative RT-PCR was based on a Taqman assay and was confirmed to be specific for XIAP. Assay linearity extended over four orders of magnitude. MDA-MB-231/U6-E1 cells and clone X-G4 stably expressing an RNAi vector against XIAP were chosen as high and low XIAP expression quality controls (QCs). Within-day and between-day coefficients of variation (CVs) in precision for cycle threshold (CT) and delta CT values (employing GAPDH and beta 2 microglobulin as housekeepers) were always less than 10%. A Western blotting technique was validated using a GST-XIAP fusion protein as a standard and HeLa cells and SF268 (human glioblastoma) cells as high and low XIAP expression QCs. Specificity of the final choice of antibody for XIAP was evaluated by analysing a panel of cell lines including clone X-G4. The assay was linear over a 29-fold range of protein concentration and between-day precision was 29% for the low QC and 23% for the high QC when normalised to GAPDH. XIAP protein was also shown to be stable at -80 degrees C for at least 60 days. M30-Apoptosense plasma Elisa detects a caspase-cleaved fragment of cytokeratin 18 (CK18), believed to be a surrogate marker for tumour cell apoptosis. Generation of an independent QC was achieved through the treatment of X-G4 cells with staurosporine and collection of media. Measurements on assay precision and kit-to-kit QC were always less than 10%. The M30 antigen (CK18-Asp396) was stable for 3 months at -80 degrees C, while at 37 degrees C it had a half-life of 80-100 h in healthy volunteer plasma. Results from the phase I trial are eagerly awaited.

Expression and genetic analysis of XIAP-associated factor 1 (XAF1) in cancer cell lines.

X-linked inhibitor of apoptosis protein (XIAP) is a potent modulator of programmed cell death. XIAP specifically binds and inhibits the function of caspase-3, -7, and -9, key effector proteases of apoptosis. We recently isolated, by yeast two-hybrid screening, a novel 34-kDa zinc finger protein, XIAP-associated factor 1 (XAF1). Both the caspase inhibiting and the anti-apoptotic abilities of XIAP were found to be blocked by overexpressed XAF1. Here, we report the isolation and characterization of the human XAF1 gene. The xaf1 gene consists of seven exons spanning 18 kb. Fluorescence in situ hybridization analysis localized the xaf1 locus at 17p13.2, telomeric to the p53 gene. The xaf1 locus was further refined to YAC 746C10, approximately 3 cM distal to TP53. Microsatellite analysis of the xaf1 locus using the NCI 60 cell line panel revealed significantly decreased heterozygosity at all three polymorphic markers tested, suggesting that allelic loss of the xaf1 gene is prevalent in cancer cell lines. Examination of the same NCI cell line panel for xaf1 RNA expression demonstrated that cancer cell lines exhibited very low levels of mRNA relative to normal human liver. In contrast, XIAP mRNA levels were relatively high in the majority of cancer cell lines tested. We propose that a high level of XIAP to XAF1 expression in cancer cells may provide a survival advantage through the relative increase of XIAP anti-apoptotic function.

Elevation of neuronal expression of NAIP reduces ischemic damage in the rat hippocampus.

We show here that transient forebrain ischemia selectively elevates levels of neuronal apoptosis inhibitory protein (NAIP) in rat neurons that are resistant to the injurious effects of this treatment. This observation suggests that increasing NAIP levels may confer protection against ischemic cell death. Consistent with this proposal, we demonstrate that two other treatments that increase neuronal NAIP levels, systemic administration of the bacterial alkaloid K252a and intracerebral injection of an adenovirus vector capable of overexpressing NAIP in vivo, reduce ischemic damage in the rat hippocampus. Taken together, these findings suggest that NAIP may play a key role in conferring resistance to ischemic damage and that treatments that elevate neuronal levels of this antiapoptotic protein may have utility in the treatment of stroke.

Chronic alterations in dopaminergic neurotransmission produce a persistent elevation of deltaFosB-like protein(s) in both the rodent and primate striatum.

Using an antibody that recognizes the products of all known members of the fos family of immediate early genes, it was demonstrated that destruction of the nigrostriatal pathway by 6-hydroxydopamine (6-OHDA) lesions of the medial forebrain bundle produces a prolonged (>3 months) elevation of Fos-like immunoreactivity in the striatum. Using retrograde tract tracing techniques, we have previously shown that this increase in Fos-like immunoreactivity is located predominantly in striatal neurons that project to the globus pallidus. In the present study, Western blots were performed on nuclear extracts from the intact and denervated striatum of 6-OHDA-lesioned rats to determine the nature of Fos-immunoreactive protein(s) responsible for this increase. Approximately 6 weeks after the 6-OHDA lesion, expression of two Fos-related antigens with apparent molecular masses of 43 and 45 kDa was enhanced in the denervated striatum. Chronic haloperidol administration also selectively elevated expression of these Fos-related antigens, suggesting that their induction after dopaminergic denervation is mediated by reduced activation of D2-like dopamine receptors. Western blot immunostaining using an antibody which recognizes the N-terminus of FosB indicated that the 43 and 45 kDa Fos-related antigens induced by dopaminergic denervation and chronic haloperidol administration may be related to a truncated form of FosB known as deltaFosB. Consistent with this proposal, retrograde tracing experiments confirmed that deltaFosB-like immunoreactivity in the deafferented striatum was located predominantly in striatopallidal neurons. Gel shift experiments demonstrated that elevated AP-1 binding activity in denervated striata contained FosB-like protein(s), suggesting that enhanced deltaFosB levels may mediate some of the effects of prolonged dopamine depletion on AP-1-regulated genes in striatopallidal neurons. In contrast, chronic administration of the D1-like receptor agonist CY 208243 to 6-OHDA-lesioned rats dramatically enhanced deltaFosB-like immunoreactivity in striatal neurons projecting to the substantia nigra. Western blot immunostaining revealed that deltaFosB and, to a lesser extent, FosB are elevated by chronic D1-like agonist administration. Both the quantitative reverse transcriptase-polymerase chain reaction and the ribonuclease protection assay demonstrated that deltafosB mRNA levels were substantially enhanced in the denervated striatum by chronic D1-like agonist administration. Lastly, we examined the effects of chronic administration ofD1-like and D2-like dopamine receptor agonists on striatal deltaFosB expression in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) primate model of Parkinson's disease. In monkeys rendered Parkinsonian by MPTP, there was a modest increase in deltaFosB-like protein(s), while the development of dyskinesia produced by chronic D1-like agonist administration was accompanied by large increases in DeltaFosB-like protein(s). In contrast, administration of the long-acting D2-like agonist cabergoline, which alleviated Parkinsonian symptoms without producing dyskinesia reduced deltaFosB levels to near normal. Taken together, these results demonstrate that chronic alterations in dopaminergic neurotransmission produce a persistent elevation of deltaFosB-like protein(s) in both the rodent and primate striatum.

Protective effect of amiloride during hypothermic hyperkalemic preservation: a 31P NMR study in isolated pig hearts.

To assess the possible role of Na+/H+ exchange in ischemia-reflow damage during cold preservation, pig hearts retrogradely perfused with Krebs-Henseleit (KH) bicarbonate buffer were arrested by increasing [K+] (to 17 mM), cooled (10 degrees C) and subjected to no flow ischemia for 15 h in the absence (C, n = 5) and in the presence of 0.5 mM amiloride (A, n = 5). A was added 7 min prior to ischemia and removed after 3 min reflow. 31P nuclear magnetic resonance (NMR) spectra were continuously acquired and functional indices were assessed prior to and after ischemia. Before reflow, the levels of phosphocreatine (PCr), ATP, inorganic phosphate (Pi)+phosphomonoesters (PME) and cytosolic pH in C and A did not differ: C, 12 +/- 7, 56 +/- 13, 427 +/- 75% of initial and 5.90 +/- 0.20; A, 15 +/- 4, 82 +/- 21, 371 +/- 60% and 5.90 +/- 0.19, respectively; no contracture occurred. Upon reflow with hyperkalemic buffer PCr recovery in A-treated hearts was greater than in C (73 +/- 21 v 49 +/- 13%, P < 0.05) and parallel increases in left ventricular end diastolic (LVEDP) and perfusion pressure took place in both groups, however these parameters remained lower in A-treated hearts. Upon switching to KH buffer the oxygen uptake rate (VO2) was higher in A than in C (79 +/- 18 v 59 +/- 6%, P < 0.05) whereas the differences in the pressure-rate product (PRP, 51 +/- 21 in A v 38 +/- 11% in C) and LVEDP (16 +/- 11 in A v 24 +/- 7 mmHg in C) did not reach statistically significant levels. Adjusting LVEDP in both groups to the same levels (19 +/- 6 v 21 +/- 9 mmHg in C) by changing balloon volume resulted in significant difference in PRP (61 +/- 19% v 42 +/- 6% in C, P < 0.02). The coronary resistance measured in beating hearts remained lower in A than in C (34.5 +/- 3.0 v 57 +/- 11 mmHg/(ml/min g), P = 0.04). To estimate contractile and metabolic reserves post-ischemic heart were challenged by increasing [Ca2+] in the perfusate from 1.0 to 1.6 mM. PRP and VO2 increased; PRP reached 71 +/- 32 (A) and 54 +/- 10% (C) and VO2 remained higher in A: 90 +/- 16 (A) v 62 +/- 4% (C) (P = 0.01) of preischemic levels. We suggest that Na+/H+ exchange may contribute to ischemia-reflow damage during cold preservation of isolated pig hearts.

Contractile dysfunction caused by normothermic ischaemia and KCL arrest in the isolated pig heart: a 31P NMR study.

The aims of this study were to assess (1) whether contractile dysfunction caused by ischaemia under hyperkalaemic conditions ("cardioplegic ischaemia") is associated with impaired energy production or abnormalities in regulation of contractility and (2) whether hyperkalaemia itself contributes to contractile dysfunction. We used 31P and 23Na NMR spectroscopy in conjunction with measurements of mechanical function and oxygen consumption in Langendorff perfused pig hearts to evaluate the mechanism of contractile failure caused by (1) total global cardioplegic (17 mM [K+]) ischaemia (36 degrees C, 50 min KCl arrest, 45 min ischaemia, 20 min reflow with high KCl) and (2) KCl arrest alone (115 min) without flow cessation. KCl arrest plus ischaemia and subsequent reperfusion (Group I) resulted in decreases in ATP (mean +/- S.D.; 61 +/- 13% of initial, n = 5; P < 0.01) and pressure-rate product (PRP) (31 +/- 9%, n = 17; P = 0.0001) while phosphocreatine (PCr), Pi, total creatine (Cr) and intracellular Na+ levels were unaffected. KCl arrest itself (Group II, n = 6) did not affect PCr, ATP or total Cr levels but decreased the PRP to 59 +/- 12% (P < 0.001). Oxygen consumption rates (Vo2) were reduced in both groups to similar levels (67 +/- 18, P < 0.01 and 77 +/- 13%, P < 0.02, respectively). The efficiency of energy conversion to mechanical work (PRP/delta VO2) decreased to 51 +/- 15 (P < 0.001) and 67 +/- 13% (P < 0.012) of initial levels, respectively. To assess metabolic and contractile reserves of post-ischaemic (n = 7) and KCl-treated (n = 3) hearts, the effects of isoproterenol (Iso) and increased Ca2+ were compared with those in normal beating hearts (Group III, n = 3). In all groups treatment with Iso (0.1 micron) greatly increased PRP (to 526 +/- 116, 203 +/- 16 and 198 +/- 8% of the level prior to stimulation (baseline), P < 0.01, respectively) and Vo2 (162 +/- 9, 153 +/-16 and 128 +/-10% of baseline, P < 0.05, Respectively). Increasing [Ca2+] from 1 to 1.66 mM produced less stimulation than Iso: PRP increased to 195 +/- 23, 156 +/- 13 and 163 +/- 22% (P < 0.05) and Vo2 increased to 138 +/- 22 (P < 0.05), 115 +/- 4 and 120 +/- 10% of baseline in Groups I, II and III, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

C-fos mediates antipsychotic-induced neurotensin gene expression in the rodent striatum.

The ubiquitous inducibility of the immediate-early gene c-fos in the central nervous system has led to the search for downstream genes which are regulated by its product, Fos. Recent evidence suggests that c-fos induction by a single injection of the classical antipsychotic haloperidol may contribute to the subsequent increase in neurotensin gene expression in the rodent striatum. Consistent with this proposal, in the present study haloperidol-induced Fos-like immunoreactivity and neurotensin/neuromedin N messenger RNA were found to be expressed by the same population of striatal neurons. Moreover, inhibition of haloperidol-induced c-fos expression by intrastriatal injection of antisense phosphorothioate oligodeoxynucleotides complimentary either to bases 109-126 or 127-144 of c-fos attenuated the subsequent increase in neurotensin/neuromedin N messenger RNA. However, injection of a sense phosphorothioate oligodeoxynucleotide corresponding to bases 127-144 of c-fos did not reduce haloperidol-induced c-fos or neurotensin/neuromedin N expression. Furthermore, constitutive expression of Jun-like immunoreactivity in the striatum was not reduced by either the sense or antisense phosphorothioate oligodeoxynucleotides. Similarly, the sense and antisense phosphorothioate oligodeoxynucleotide failed to reduce proenkephalin messenger RNA, which is located in the same striatal neurons that express haloperidol-induced neurotensin/neuromedin N messenger RNA, which is located in the same striatal neurons that express haloperidol-induced neurotensin/neuromedin N messenger RNA. Lastly, haloperidol-induced increases in nerve growth factor I-A-, JunB- and FosB-like immunoreactivity and fosB messenger RNA were not decreased by intrastriatal injection of either the sense or antisense phosphorothioate oligodeoxynucleotides. These results indicate that the antisense phosphorothioate oligodeoxynucleotides attenuated haloperidol-induced neurotensin/neuromedin N expression by selectively reducing c-fos expression and emphasize the potential importance of immediate-early gene induction in the mechanism of action of this antipsychotic drug.

Energy metabolism, intracellular Na+ and contractile function in isolated pig and rat hearts during cardioplegic ischemia and reperfusion: 23Na- and 31P-NMR studies.

The purpose of the study was to compare the role of Na ions in the damage caused by cardioplegic ischemia in fast (rat) and slow (pig) hearts. Changes in intracellular Na+ (Na+i), high energy phosphates, and contractile function were assessed during ischemia (36 degrees C) and reperfusion in KCl-arrested perfused hearts using 31P-NMR and shift reagent (DyTTHA3-)-aided 23Na-NMR spectroscopy. In the pig hearts the rates of decrease of phosphocreatine (PCr), ATP and intracellular pH (pHi) were 3-4 times slower than the rates observed in the rat hearts. In the pig hearts PCr was observable (approximately 10%) during first 80 min of the ischemic period (90 min). Comparable decreases in ATP (32.0 +/- 6 vs. 38 +/- 15% of initial) and pHi, (to 6.14 +/- 0.06 vs. 6.10 +/- 0.15) observed after 90 and 20 min ischemia in pig and rat hearts, respectively, were associated with a smaller Na+i increase in the pig hearts (to 175 +/- 31%) than in the rat hearts (to 368 +/- 62%). This Na+ increase in the rat hearts preceded development of ischemic contracture (41 +/- 6 mmHg at 23.6 +/- 0.7 min) while no contracture was observed in pig hearts. Reperfusion of the rat hearts (at 30 min ischemia) was followed by partial recovery of PCr (44 +/- 3%) and Na+i (234 +/- 69%) and poorer recovery of the pressure-rate product (PRP, 9 +/- 4%) and end-diastolic pressure (EDP, 72 +/- 5 mmHg) compared to the pig hearts (PCr, 106 +/- 25%; Na+i, 82 +/- 17%; PRP, 24 +/- 3%; EDP, 4.6 +/- 2.5 mmHg). The loss of function in the pig hearts was reversed by increasing Ca++ in the perfusate from 1 to 2.3 mM and resulted in a rise in both PRP and oxygen consumption rate, V(O2), from 24 +/- 3.3 to 64.5 +/- 5.8% and from 55 +/- 10 to 74 +/- 10% of the control levels, respectively. The PRP/delta V(O2) ratio was halved in the post-ischemic pig hearts and returned to the pre-ischemic level following Ca++ stimulation. It is suggested that the higher stability of Na+ homeostasis to ischemic stress in the pig heart may result from: 1) a lower ratio of the rate of ATP hydrolysis to glycolytic ATP production; 2) differences in the kinetic properties of the Na+ transporters. Reduced Na+ accumulation during ischemia and reperfusion is beneficial for metabolic and functional preservation of cardiomyocytes.

Modulation of lung-associated natural killer activity by resident and activated alveolar macrophages.

Alveolar macrophages (AM) freshly obtained by bronchoalveolar lavage suppressed significantly, in a dose-dependent fashion, lung interstitial lymphocytes cytotoxicity against the NK-sensitive target cells, YAC-1. Kinetic experiments revealed that AM-mediated suppression of NK activity was seen following short-term incubation of AM with lymphocytes (4 h) and was unchanged after a 24 h co-culture period. Freshly obtained lung lymphocytes and lymphocytes incubated for 24 h were similarly inhibited by AM. In addition, incubation of AM for 24 h did not abrogate their suppressive effect on lung NK activity. Interestingly, AM-conditioned media, also caused a significant inhibition of lung NK activity. Furthermore, in vitro activation of AM with lipopolysaccharide (LPS, 5 micrograms/ml) and muramyl dipeptide (MDP, 20 micrograms/ml) significantly enhanced the inhibitory effect of AM on lung NK activity. Similarly, in vivo activation of AM locally by intratracheal instillation of attapulgite, an inflammatory agent, resulted in greater AM-mediated down regulation. Taken together, these data indicate that lung NK activity is modulated by locally derived factors and suggest that pharmacologic manipulation of AM may play a determining role in the activation of lung NK activity by biological response modifiers (BRM).

The effects of glucose and insulin on contraction of the isolated diaphragm.

High glucose concentrations (55 mM) were found to suppress the isometric contraction tension of rat diaphragm. The effect appears to be due to the resulting transmembrane osmotic gradient in spite of the fact that glucose uptake by the diaphragm is fairly rapid. Insulin can reverse the effect of hypertonic glucose to a considerable extent. The problems of estimating intracellular glucose concentration in the isolated muscle are considered. Estimates of intracellular glucose taking into account extracellular space and extracellular diffusion gradients were made using a two-compartment model. Calculations based on the model show that in the presence of insulin, intracellular glucose increases from about 1 to 19 mumol/ml of muscle fibre. The mean transmembrane glucose concentration gradient dcreases from 41 to 18 mumol/ml. With the use of the model it appears possible to relate most of the observed effect of glucose and insulin on isometric contraction to their influence on the osmotic gradient across the muscle fibre membrane. Insulin appears to have some additional effects on muscles suppressed by hypertonic solutions which are not accounted for by this mechanism.