Extra-mandibular Osteoradionecrosis after the Treatment of Head and Neck Cancer

AIMS

Osteoradionecrosis (ORN) is a serious toxicity of head and neck radiotherapy. It predominantly affects the mandible. Extra-mandibular ORN is rare. The aim of this study was to report the incidence and outcomes of extra-mandibular ORNs from a large institutional database.

MATERIALS AND METHODS

In total, 2303 head and neck cancer patients were treated with radical or adjuvant radiotherapy. Of these, extra-mandibular ORN developed in 13 patients (0.5%).

RESULTS

Maxillary ORNs (n = 8) were a consequence of the treatment of various primaries (oropharynx = 3, sinonasal = 2, maxilla = 2, parotid = 1). The median interval from the end of radiotherapy to the development of ORN was 7.5 months (range 3-42 months). The median radiotherapy dose in the centre of the ORN was 48.5 Gy (range 22-66.5 Gy). Four patients (50%) healed in 7, 14, 20 and 41 months. All temporal bone ORNs (n = 5) developed after treatment to the parotid gland (of a total of 115 patients who received radiotherapy for parotid gland malignancy). The median interval from the end of radiotherapy to the development of ORN was 41 months (range 20-68 months). The median total dose in the centre of the ORN was 63.5 Gy (range 60.2-65.3 Gy). ORN healed in only one patient after 32 months of treatment with repeated debridement and topical betamethasone cream.

CONCLUSION

Extra-mandibular ORN is a rare late toxicity and this current study provides useful information on its incidence and outcome. The risk of temporal bone ORN should be considered in the treatment of parotid malignancies and patients should be counselled. More research is required to determine the optimal management of extra-mandibular ORN, particularly on the role of the PENTOCLO regimen.

Design of a Potent, Selective, and Brain-Penetrant Inhibitor of Wnt-Deactivating Enzyme Notum by Optimization of a Crystallographic Fragment Hit

Notum is a carboxylesterase that suppresses Wnt signaling through deacylation of an essential palmitoleate group on Wnt proteins. There is a growing understanding of the role Notum plays in human diseases such as colorectal cancer and Alzheimer's disease, supporting the need to discover improved inhibitors, especially for use in models of neurodegeneration. Here, we have described the discovery and profile of 8l (ARUK3001185) as a potent, selective, and brain-penetrant inhibitor of Notum activity suitable for oral dosing in rodent models of disease. Crystallographic fragment screening of the Diamond-SGC Poised Library for binding to Notum, supported by a biochemical enzyme assay to rank inhibition activity, identified 6a and 6b as a pair of outstanding hits. Fragment development of 6 delivered 8l that restored Wnt signaling in the presence of Notum in a cell-based reporter assay. Assessment in pharmacology screens showed 8l to be selective against serine hydrolases, kinases, and drug targets.

Osteoradionecrosis after treatment of head and neck cancer: a comprehensive analysis of risk factors with a particular focus on role of dental extractions

In head and cancer (HNC), osteoradionecrosis (ORN) is one of the most significant complications of radiotherapy (RT). With an absence of effective non-surgical treatment, prevention of the development of ORN is the best approach. The purpose of this study was to identify the risk factors for the development of ORN in HNC. Records of 1,118 patients with HNC treated with radical RT (≥55Gy) from January 2010 to December 2019 were reviewed. After applying the exclusion criteria, 935 patients were included in the final analysis. In patients with confirmed ORN, exact RT doses were mapped. In total, 91 patients were found (9.7%) with a median (range) time of eight (3-89) months to the development of ORN. Smoking, having a primary site in the oropharynx, bone surgery before adjuvant RT, the addition of concurrent chemotherapy, the presence of xerostomia, dental extraction pre-RT, the time ≤20 days between dental extraction and start of RT, and receiving >55Gy RT dose were significant factors for its development. This comprehensive analysis including the precise RT dose mapping has shown the risk factors for the development of ORN. In practice, every effort should be made to avoid these risk factors without compromising the oncology treatment. The findings of this analysis may provide a basis for future prospective research on this topic.

Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions

The PHENIX collaboration presents first measurements of low-momentum (0.4<p_{T}<3  GeV/c) direct-photon yields from Au+Au collisions at sqrt[s_{NN}]=39 and 62.4 GeV. For both beam energies the direct-photon yields are substantially enhanced with respect to expectations from prompt processes, similar to the yields observed in Au+Au collisions at sqrt[s_{NN}]=200. Analyzing the photon yield as a function of the experimental observable dN_{ch}/dη reveals that the low-momentum (>1  GeV/c) direct-photon yield dN_{γ}^{dir}/dη is a smooth function of dN_{ch}/dη and can be well described as proportional to (dN_{ch}/dη)^{α} with α≈1.25. This scaling behavior holds for a wide range of beam energies at the Relativistic Heavy Ion Collider and the Large Hadron Collider, for centrality selected samples, as well as for different A+A collision systems. At a given beam energy, the scaling also holds for high p_{T} (>5  GeV/c), but when results from different collision energies are compared, an additional sqrt[s_{NN}]-dependent multiplicative factor is needed to describe the integrated-direct-photon yield.

Measurement of direct photons in Au+Au collisions at √(s(NN))=200 GeV

We report the measurement of direct photons at midrapidity in Au+Au collisions at √(s(NN))=200 GeV. The direct photon signal was extracted for the transverse momentum range of 4 GeV/c<p(T)<22 GeV/c, using a statistical method to subtract decay photons from the inclusive photon sample. The direct photon nuclear modification factor R(AA) was calculated as a function of p(T) for different Au+Au collision centralities using the measured p+p direct photon spectrum and compared to theoretical predictions. R(AA) was found to be consistent with unity for all centralities over the entire measured p(T) range. Theoretical models that account for modifications of initial direct photon production due to modified parton distribution functions in Au and the different isospin composition of the nuclei predict a modest change of R(AA) from unity. They are consistent with the data. Models with compensating effects of the quark-gluon plasma on high-energy photons, such as suppression of jet-fragmentation photons and induced-photon bremsstrahlung from partons traversing the medium, are also consistent with this measurement.

Dosimetric and radiobiological comparison of helical tomotherapy, forward-planned intensity-modulated radiotherapy and two-phase conformal plans for radical radiotherapy treatment of head and neck squamous cell carcinomas

OBJECTIVES

The usual radical radiotherapy treatment prescribed for head and neck squamous cell carcinoma (HNSCC) is 70 Gy (in 2 Gy per fraction equivalent) administered to the high-risk target volume (TV). This can be planned using either a forward-planned photon-electron junction technique (2P) or a single-phase (1P) forward-planned technique developed in-house. Alternatively, intensity-modulated radiotherapy (IMRT) techniques, including helical tomotherapy (HT), allow image-guided inversely planned treatments. This study was designed to compare these three planning techniques with regards to TV coverage and the dose received by organs at risk.

METHODS

We compared the dose-volume histograms and conformity indices (CI) of the three planning processes in five patients with HNSCC. The tumour control probability (TCP), normal tissue complication probability (NTCP) and uncomplicated tumour control probability (UCP) were calculated for each of the 15 plans. In addition, we explored the radiobiological rationality of a dose-escalation strategy.

RESULTS

The CI for the high-risk clinical TV (CTV1) in the 5 patients were 0.78, 0.76, 0.82, 0.72 and 0.81 when HT was used; 0.58, 0.56, 0.47, 0.35 and 0.60 for the single-phase forward-planned technique and 0.46, 0.36, 0.29, 0.22 and 0.49 for the two-phase technique. The TCP for CTV1 with HT were 79.2%, 85.2%, 81.1%, 83.0% and 53.0%; for single-phase forward-planned technique, 76.5%, 86.9%, 73.4%, 81.8% and 31.8% and for the two-phase technique, 38.2%, 86.2%, 42.7%, 0.0% and 3.4%. Dose escalation using HT confirmed the radiobiological advantage in terms of TCP.

CONCLUSION

TCP for the single-phase plans was comparable to that of HT plans, whereas that for the two-phase technique was lower. Centres that cannot provide IMRT for the radical treatment of all patients could implement the single-phase technique as standard to attain comparable TCP. However, IMRT produced better UCP, thereby enabling the exploration of dose escalation.

Midrapidity antiproton-to-proton ratio in pp collisons at sqrt[s]=0.9 and 7 TeV measured by the ALICE experiment

The ratio of the yields of antiprotons to protons in pp collisions has been measured by the ALICE experiment at sqrt[s]=0.9 and 7 TeV during the initial running periods of the Large Hadron Collider. The measurement covers the transverse momentum interval 0.45<p_{t}<1.05  GeV/c and rapidity |y|<0.5. The ratio is measured to be R_{|y|<0.5}=0.957±0.006(stat)±0.014(syst) at 0.9 TeV and R_{|y|<0.5}=0.991±0.005(stat)±0.014(syst) at 7 TeV and it is independent of both rapidity and transverse momentum. The results are consistent with the conventional model of baryon-number transport and set stringent limits on any additional contributions to baryon-number transfer over very large rapidity intervals in pp collisions.

Enhanced production of direct photons in Au + Au collisions at square root(S(NN)) = 200 GeV and implications for the initial temperature

The production of e+ e- pairs for m(e+ e-)<0.3 GeV/c2 and 1<p(T)<5 GeV/c is measured in p+p and Au+Au collisions at square root(S(NN))=200 GeV. An enhanced yield above hadronic sources is observed. Treating the excess as photon internal conversions, the invariant yield of direct photons is deduced. In central Au+Au collisions, the excess of the direct photon yield over p+p is exponential in transverse momentum, with an inverse slope T=221+/-19(stat)+/-19(syst) MeV. Hydrodynamical models with initial temperatures ranging from T(init) approximately 300-600 MeV at times of approximately 0.6-0.15 fm/c after the collision are in qualitative agreement with the data. Lattice QCD predicts a phase transition to quark gluon plasma at approximately 170 MeV.

Charged Kaon interferometric probes of space-time evolution in Au+Au collisions at sqrt[S(NN)]=200 GeV

Bose-Einstein correlations of charged kaons are used to probe Au+Au collisions at sqrt[S(NN)]=200 GeV and are compared to charged pion probes, which have a larger hadronic scattering cross section. Three-dimensional Gaussian source radii are extracted, along with a one-dimensional kaon emission source function. The centrality dependences of the three Gaussian radii are well described by a single linear function of N(part)1/3 with a zero intercept. Imaging analysis shows a deviation from a Gaussian tail at r greater than or approximately equal to 10 fm, although the bulk emission at lower radius is well described by a Gaussian. The presence of a non-Gaussian tail in the kaon source reaffirms that the particle emission region in a heavy-ion collision is extended, and that similar measurements with pions are not solely due to the decay of long-lived resonances.

Suppression pattern of neutral pions at high transverse momentum in Au + Au collisions at sqrt[sNN]=200 GeV and constraints on medium transport coefficients

For Au + Au collisions at 200 GeV, we measure neutral pion production with good statistics for transverse momentum, pT, up to 20 GeV/c. A fivefold suppression is found, which is essentially constant for 5 < pT < 20 GeV/c. Experimental uncertainties are small enough to constrain any model-dependent parametrization for the transport coefficient of the medium, e.g., q in the parton quenching model. The spectral shape is similar for all collision classes, and the suppression does not saturate in Au + Au collisions.

Particle-species dependent modification of jet-induced correlations in Au+Au collisions at sqrt[s_{NN}]=200 GeV

Measurements in Au+Au collisions at sqrt[s_{NN}]=200 GeV of jet correlations for a trigger hadron at intermediate transverse momentum (p_{T,trig}) with associated mesons or baryons at lower p_{T,assoc} indicate strong modification of the away-side jet. The ratio of jet-associated baryons to mesons increases with centrality and p_{T,assoc}. For the most central collisions, the ratio is similar to that for inclusive measurements. This trend is incompatible with in-vacuum fragmentation but could be due to jetlike contributions from correlated soft partons, which recombine upon hadronization.

Source breakup dynamics in Au + Au collisions at sqrt[s(NN)]=200 GeV via three-dimensional two-pion source imaging

A three-dimensional correlation function obtained from midrapidity, low p(T), pion pairs in central Au+Au collisions at sqrt[s(NN)]=200 GeV is studied. The extracted model-independent source function indicates a long range tail in the directions of the pion pair transverse momentum (out) and the beam (long). A proper breakup time tau(0) ~ 9 fm/c and a mean proper emission duration Delta tau ~ 2 fm/c, leading to sizable emission time differences ({|Delta t(LCM)|} approximately 12 fm/c), are required to allow models to be successfully matched to these tails. The model comparisons also suggest an outside-in "burning" of the emission source reminiscent of many hydrodynamical models.

Elliptic flow for phi mesons and (anti)deuterons in Au+Au collisions at square root of sNN=200 GeV

Differential elliptic flow (v(2)) for phi mesons and (anti)deuterons (d)d is measured for Au+Au collisions at square root of sNN=200 GeV. The v(2) for phi mesons follows the trend of lighter pi+/- and K+/- mesons, suggesting that ordinary hadrons interacting with standard hadronic cross sections are not the primary driver for elliptic flow development. The v(2) values for (d)d suggest that elliptic flow is additive for composite particles. This further validation of the universal scaling of v(2) per constituent quark for baryons and mesons suggests that partonic collectivity dominates the transverse expansion dynamics.

System size and energy dependence of jet-induced hadron pair correlation shapes in Cu+Cu and Au+Au collisions at square root sNN=200 and 62.4 GeV

We present azimuthal angle correlations of intermediate transverse momentum (1-4 GeV/c) hadrons from dijets in Cu+Cu and Au+Au collisions at square root sNN=62.4 and 200 GeV. The away-side dijet induced azimuthal correlation is broadened, non-Gaussian, and peaked away from Delta phi=pi in central and semicentral collisions in all the systems. The broadening and peak location are found to depend upon the number of participants in the collision, but not on the collision energy or beam nuclei. These results are consistent with sound or shock wave models, but pose challenges to Cherenkov gluon radiation models.

J/psi production versus centrality, transverse momentum, and rapidity in Au+Au collisions at square root sNN=200 GeV

The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured J/psi production for rapidities -2.2<y<2.2 in Au+Au collisions at square root sNN=200 GeV. The J/psi invariant yield and nuclear modification factor RAA as a function of centrality, transverse momentum, and rapidity are reported. A suppression of J/psi relative to binary collision scaling of proton-proton reaction yields is observed. Models which describe the lower energy J/psi data at the CERN Super Proton Synchrotron invoking only J/psi destruction based on the local medium density predict a significantly larger suppression at RHIC and more suppression at midrapidity than at forward rapidity. Both trends are contradicted by our data.

Scaling properties of azimuthal anisotropy in Au+Au and Cu+Cu Collisions at sqrt[s NN]=200 GeV

Differential measurements of elliptic flow (v2) for Au+Au and Cu+Cu collisions at sqrt[sNN]=200 GeV are used to test and validate predictions from perfect fluid hydrodynamics for scaling of v2 with eccentricity, system size, and transverse kinetic energy (KE T). For KE T identical with mT-m up to approximately 1 GeV the scaling is compatible with hydrodynamic expansion of a thermalized fluid. For large values of KE T mesons and baryons scale separately. Quark number scaling reveals a universal scaling of v2 for both mesons and baryons over the full KE T range for Au+Au. For Au+Au and Cu+Cu the scaling is more pronounced in terms of KE T, rather than transverse momentum.

Measurement of direct photon production in p+p collisions at sqrt[s] = 200 GeV

Cross sections for midrapidity production of direct photons in p+p collisions at the Relativistic Heavy Ion Collider (RHIC) are reported for transverse momenta of 3 < pT < 16 GeV/c. Next-to-leading order perturbative QCD (pQCD) describes the data well for pT >5 GeV/c, where the uncertainties of the measurement and theory are comparable. We also report on the effect of requiring the photons to be isolated from parton jet energy. The observed fraction of isolated photons is well described by pQCD for pT >7 GeV/c.

Azimuthal angle correlations for rapidity separated Hadron pairs in d+Au collisions at square root of sNN=200 GeV

Deuteron-gold (d+Au) collisions at the Relativistic Heavy Ion Collider provide ideal platforms for testing QCD theories in dense nuclear matter at high energy. In particular, models suggesting strong saturation effects for partons carrying small nucleon momentum fraction (x) predict modifications to jet production at forward rapidity (deuteron-going direction) in d+Au collisions. We report on two-particle azimuthal angle correlations between charged hadrons at forward/backward (deuteron/gold going direction) rapidity and charged hadrons at midrapidity in d+Au and p+p collisions at square root of sNN=200 GeV. Jet structures observed in the correlations are quantified in terms of the conditional yield and angular width of away-side partners. The kinematic region studied here samples partons in the gold nucleus with x~0.1 to ~0.01. Within this range, we find no x dependence of the jet structure in d+Au collisions.

J/psi production and nuclear effects for d + Au and p + p collisions at square root of S(NN) = 200 GeV

J/psi production in d + Au and p + p collisions at square root of S(NN) = 200 GeV has been measured by the PHENIX experiment at rapidities -2.2 < y < +2.4. The cross sections and nuclear dependence of J/psi production versus rapidity, transverse momentum, and centrality are obtained and compared to lower energy p + A results and to theoretical models. The observed nuclear dependence in d + Au collisions is found to be modest, suggesting that the absorption in the final state is weak and the shadowing of the gluon distributions is small and consistent with Dokshitzer-Gribov-Lipatov-Altarelli-Parisi-based parametrizations that fit deep-inelastic scattering and Drell-Yan data at lower energies.

Saturation of azimuthal anisotropy in Au + Au collisions at (square root)s(NN) = 62-200 GeV

New measurements are presented for charged hadron azimuthal correlations at midrapidity in Au+Au collisions at (square root)s(NN) = 62.4 and 200 GeV. They are compared to earlier measurements obtained at (square root)s(NN) = 130 GeV and in Pb + Pb collisions at (square root)s(NN) = 17.2 GeV. Sizeable anisotropies are observed with centrality and transverse momentum (pT) dependence characteristic of elliptic flow (upsilon2). For a broad range of centralities, the observed magnitudes and trends of the differential anisotropy, upsilon2(pT), change very little over the collision energy range (square root)s(NN) = 62-200 GeV, indicating saturation of the excitation function for upsilon2 at these energies. Such a saturation may be indicative of the dominance of a very soft equation of state for (square root)s(NN) approximately 60-200 GeV.

Nuclear modification factors for hadrons at forward and backward rapidities in deuteron-gold collisions at sqrt[s(NN)]=200 GeV

We report on charged hadron production in deuteron-gold reactions at sqrt[s(NN)]=200 GeV. Our measurements in the deuteron direction cover 1.4<eta<2.2, referred to as forward rapidity, and in the gold direction -2.0<eta<-1.4, referred to as backward rapidity, and a transverse momentum range p(T)=0.5-4.0 GeV/c. We compare the relative yields for different deuteron-gold collision centrality classes. We observe a suppression relative to binary collision scaling at forward rapidity, sensitive to low momentum fraction (x) partons in the gold nucleus, and an enhancement at backward rapidity, sensitive to high momentum fraction partons in the gold nucleus.

Double helicity asymmetry in inclusive midrapidity pi0 production for polarized p+p collisions at square root s = 200 GeV

We present a measurement of the double longitudinal spin asymmetry in inclusive pi(0) production in polarized proton-proton collisions at sqrt[s]=200 GeV. The data were taken at the Relativistic Heavy Ion Collider with average beam polarizations of 0.27. The measurements are the first in a program to study the longitudinal spin structure of the proton, using strongly interacting probes, at collider energies. The asymmetry is presented for transverse momenta 1-5 GeV/c at midrapidity, where next-to-leading-order perturbative quantum chromodynamic (NLO pQCD) calculations well describe the unpolarized cross section. The observed asymmetry is small and is compared to a NLO pQCD calculation with a range of polarized gluon distributions.

Absence of suppression in particle production at large transverse momentum in sqrt[s(NN)]=200 GeV d+Au collisions

Transverse momentum spectra of charged hadrons with p(T)<8 GeV/c and neutral pions with p(T)<10 GeV/c have been measured at midrapidity by the PHENIX experiment at BNL RHIC in d+Au collisions at sqrt[s(NN)]=200 GeV. The measured yields are compared to those in p+p collisions at the same sqrt[s(NN)] scaled up by the number of underlying nucleon-nucleon collisions in d+Au. The yield ratio does not show the suppression observed in central Au+Au collisions at RHIC. Instead, there is a small enhancement in the yield of high momentum particles.

Transforming growth factor-beta 1 does not relate to hypertension in pre-eclampsia

1. Pre-eclampsia is a human disease of pregnancy characterized by high blood pressure, proteinuria and end-organ damage, if severe. Pre-eclampsia is thought to be related to changes in early placental development, with the formation of a shallower than normal placental bed. 2. Transforming growth factor (TGF)-beta1 is a multifunctional fibrogenic growth factor involved in immune regulation that is elevated in some populations with a high risk of hypertensive end-organ disease related to increases in endothelin release. Transforming growth factor-beta1 is also an important factor in placental implantation. Alterations in TGF-beta1 may be related to abnormal placental development in early pregnancy and, thus, are a candidate for the development of hypertension in pre-eclampsia. 3. The aim of the present study was to examine the placental distribution and serum concentration of TGF-beta1 in patients with pre-eclampsia compared with normal pregnancy. 4. Patients with pre-eclampsia (n = 12) were compared with patients with normal pregnancy (n = 14). Transforming growth factor-beta1 was determined by TGF-beta1 Max ELISA (Promega, Madsion, WI, USA) after serum dilution (1/150) and acid activation. Placental distribution was determined by immunostaining with TGF-beta1 (Santa Cruz, Santa Cruz, CA, USA; 20 ng/mL) and the villi and decidual trophoblast were scored for intensity and extent of staining. 5. Patients with pre-eclampsia had a mean gestational age of 36 weeks, whereas those with a normal pregnancy had a mean gestational age of 39.0 +/- 0.4 weeks. There was no difference in TGF-beta1 concentration between the two groups (mean (+/-SEM) 27.1 +/- 1.0 vs 26.4 +/- 0.7 pg/mL for normal pregnancy and pre-eclampsia, respectively; P = 0.73, Mann-Whitney U-test). There was no correlation between systolic or diastolic blood pressure and TGF-beta1 concentration (regression analysis P = 0.4 and 0.2). Immunostaining was absent in the villous trophoblast cells and endovascular and extravillous trophoblast of term placentas. 6. Although TGF-beta1 is present in trophoblast cells in early pregnancy during placental development, TGF-beta1 concentrations were not increased in the placenta at term in pre-eclampsia and there was no correlation between blood pressure and serum TGF-beta1, suggesting that TGF-beta1 does not play a role in the development of late gestation pre-eclampsia and hypertension.

Analysis of lung tumor initiation and progression using conditional expression of oncogenic K-ras

Adenocarcinoma of the lung is the most common form of lung cancer, but the cell of origin and the stages of progression of this tumor type are not well understood. We have developed a new model of lung adenocarcinoma in mice harboring a conditionally activatable allele of oncogenic K-ras. Here we show that the use of a recombinant adenovirus expressing Cre recombinase (AdenoCre) to induce K-ras G12D expression in the lungs of mice allows control of the timing and multiplicity of tumor initiation. Through the ability to synchronize tumor initiation in these mice, we have been able to characterize the stages of tumor progression. Of particular significance, this system has led to the identification of a new cell type contributing to the development of pulmonary adenocarcinoma.

Non-corticosteroid treatment for nephrotic syndrome in children

BACKGROUND

Eighty to ninety per cent children with steroid sensitive nephrotic syndrome (SSNS) have one or more relapses. About half of these children relapse frequently and are at risk of the adverse effects of corticosteroids. Non-corticosteroid immunosuppressive agents are used to prolong periods of remission in children, who relapse frequently. However these non-corticosteroid agents also have significant potential adverse effects. Currently there is no consensus as to the most appropriate second line agent in children who are steroid sensitive, but who continue to relapse. In this systematic review of randomised controlled trials (RCTs), the benefits and harms of these immunosuppressive agents are evaluated.

OBJECTIVES

To evaluate the benefits and harms of non-corticosteroid immunosuppressive agents in relapsing SSNS in children.

SEARCH STRATEGY

Published and unpublished randomised controlled trials were identified from the Cochrane Controlled Trials Register, MEDLINE, EMBASE, reference lists of articles, abstracts from proceedings and contact with known investigators in the area.

SELECTION CRITERIA

Randomised or quasi-randomised trials were included if they were carried out in children (aged three months to 18 years) with relapsing SSNS, if they compared non-corticosteroid agents with placebo, prednisone or no treatment, different doses and/ or durations of the same non-corticosteroid agent, different non-corticosteroid agents and if they had outcome data at six months or more.

DATA COLLECTION AND ANALYSIS

Two reviewers independently reviewed all eligible studies for inclusion, assessed study quality and extracted data. The principle outcome measure was the number of children with and without relapse after six and 12 to 24 months. Secondary outcomes sought were the mean time to next relapse, the mean number of relapses per year and adverse events. A random effects model was used to estimate summary effect measures after testing for heterogeneity. Examination of possible between-study differences due to study quality, different interventions and different populations was attempted by subgroup analysis.

MAIN RESULTS

Eighteen trials involving 828 children were identified. Cyclophosphamide (three trials; relative risk (RR) 0.44; 95% confidence intervals (95% CI) 0.26 to 0.73) and chlorambucil (two trials; RR 0.13; 95% CI 0.03 to 0.57) significantly reduced the relapse risk at six to twelve months compared with prednisone alone. In the single chlorambucil versus cyclophosphamide trial, there was no observed difference in relapse risk at two years (RR 1.31; 95% CI 0.80 to 2.13). Cyclosporin was as effective as cyclophosphamide (one trial, RR 1.07; 95% CI 0.48 to 2.35) and chlorambucil (one trial, RR 0.82; 95% CI 0.44 to 1.53) but the effect was not sustained when cyclosporin was ceased. During treatment levamisole (three trials, RR 0.60; 95% CI 0.45 to 0.79) was more effective than steroids alone but the effect was not sustained. Mizoribine (one trial) and azathioprine (two trials) were no more effective than placebo or prednisone alone in maintaining remission.

REVIEWER'S CONCLUSIONS

Eight weeks courses of cyclophosphamide or chorambucil and prolonged courses of cyclosporin and levamisole reduce the risk of relapse in children with relapsing SSNS compared with corticosteroids alone. Clinically important differences in efficacy among these agents are possible and further comparative trials are still needed. Meanwhile choice between these agents depends on physician and patient preferences related to therapy duration and the type and frequency of complications.

Acute volume expansion and salt-loading studies in rats. The role of atrial natriuretic peptide and catecholamines

Differences have been postulated for the mechanism of natriuresis due to atrial natriuretic peptide (ANP), salt loading with high salt diet (HS) and acute volume expansion (AcVE), in particular between AcVE and ANP based on the observed synergism between the two. Therefore the effects of and the interaction between the three were investigated in rats. ANP and AcVE produced the same natriuresis in HS as in normal salt (NS) rats and, in both, the actions of ANP and AcVe were significantly additive showing similarity in mechanisms. Synergism [(AcVE + ANP) - AcVE] was, however, present only in the NS rats. Proximal tubular sodium transport was the same with AcVE and ANP+AcVE suggesting that synergism is a property of more distal nephron segments. In conscious HS rats, plasma ANP was significantly less but natriuresis was higher than in NS rats. ANP therefore probably has some causative role in the natriuresis of AcVE but none in that of HS loading. Urinary dopamine was significantly increased by HS and further increased by AcVE in both NS and HS rats, the relationship between dopamine and natriuresis being significantly positive (r2 = 0.328) reaching equivalent levels in both NS and HS rats. Systemic benserazide prevented the increase in urinary dopamine but only attenuated the natriuresis of AcVE. We conclude that HS does not potentiate the natriuresis of AcVE or ANP, synergism between AcVE and ANP is not a proximal tubule event and dopamine accounts for significant natriuresis of VE in addition to other natriuretic factors.

The coxsackie-adenovirus receptor (CAR) is used by reference strains and clinical isolates representing all six serotypes of coxsackievirus group B and by swine vesicular disease virus

Group B coxsackieviruses are etiologically linked to many human diseases, and cell surface receptors are postulated to play an important role in mediating their pathogenesis. The coxsackievirus adenovirus receptor (CAR) has been shown to function as a receptor for selected strains of coxsackievirus group B (CVB) serotypes 3, 4, and 5 and is postulated to serve as a receptor for all six serotypes. In this study, we demonstrate that CAR can serve as a receptor for laboratory reference strains and clinical isolates of all six CVB serotypes. Infection of CHO cells expressing human CAR results in a 1000-fold increase in CVB progeny virus titer compared to mock transfected cells. CAR was shown to be a functional receptor for swine vesicular disease virus (SVDV), as CHO-CAR cells but not CHO mock transfected controls were susceptible to SVDV infection, produced progeny SVDV, and developed cytopathic effects. Moreover, SVDV infection could be specifically blocked by monoclonal antibody to CAR (RmcB). SVDV infection of HeLa cells was also inhibited by an anti-CD55 MAb, suggesting that this virus, like some CVB, may interact with CD55 (decay accelerating factor) in addition to CAR. Finally, pretreatment of CVB or SVDV with soluble CAR effectively blocks virus infection of HeLa cell monolayers.

Blood volume determination by the carbon monoxide method using a new delivery system: accuracy in critically ill humans and precision in an animal model

OBJECTIVE

To evaluate accuracy and repeatability of blood volume determinations made by the carbon monoxide method, using a ventilator-driven administration system.

DESIGN

Prospective within-patient comparison, using simultaneous measurements by two methods to determine accuracy. Prospective laboratory investigation in animals to estimate repeatability.

SUBJECTS

For accuracy: Nineteen ventilated critically ill patients in a university hospital intensive care unit. For repeatability: Six anesthetized, mechanically ventilated normovolemic pigs because this is impossible to perform in humans.

INTERVENTIONS

In the accuracy study, a small mass of carbon monoxide was administered via a closed breathing system and arterial blood samples were taken from existing cannulas. In the repeatability study, an intramuscular sedative was given, followed by an inhalational anesthetic induction and mechanical ventilation via a tracheal tube. Left axillary artery and external jugular vein cannulas were sited. Anesthesia was maintained using an intravenous infusion. Five sequential circulating hemoglobin and blood volume estimations were made using the carbon monoxide method.

MEASUREMENTS AND MAIN RESULTS

The small carboxyhemoglobin increase produced by uptake of a small, known mass of carbon monoxide was used to estimate the circulating blood volume. Simultaneous measurement, using 51Cr-labeled red blood cells, was performed. Twenty measurements were made in 19 patients. The bias (mean difference between blood volume measurements by the two methods) was 397 mL (5.53 mL x kg(-1)) +/-415 mL (+/-5.95 mL x kg(-1)); the limits of agreement (mean difference +/-2 SD) were -433 mL and 1227 mL (-6.36 mL x kg(-1) and 17.42 mL x kg(-1)). Therefore, 95% of expected differences will lie between these limits. The mean blood volume was 75.8 mL x kg(-1) in the animals. The coefficient of variation of repeated estimates was 9.49%. Mean circulating hemoglobin mass was 7.31 mmol with a coefficient of variation of 10.18%. The mean hemoglobin concentration, by co-oximetry, was 5.014 mmol x L(-1), coefficient of variation, 2.99%.

CONCLUSION

This arrangement is a potential bedside method of estimating blood volume and circulating hemoglobin mass. We have rendered the technique more acceptable clinically by creating a ventilator-driven administration system.

Double-blind placebo controlled trial of dextrose tablets and nicotine patch in smoking cessation

In a placebo-controlled double-blind trial 308 smokers were individually randomly allocated to one of four groups: 1) 3 g dextrose tablets and 15 mg nicotine transdermal patch; 2) dextrose and placebo patch; 3) placebo tablets and nicotine patch; 4) placebo tablets and placebo patch. Patients were scheduled to attend weekly smokers clinic sessions starting 1 week before the quit date and continue for 4 weeks after that date. The primary outcome variable was biochemically verified abstinence at the final session, four weeks after the scheduled quit date. The proportion of smokers abstinent in the four groups was as follows: 49% - dextrose plus active patch; 44% - dextrose plus placebo patch; 36% - placebo tablet plus active patch; 30% - placebo tablet plus placebo patch. The difference between the dextrose and placebo tablets (13%) was statistically significant (P < 0.01, one-tailed); the difference between the active and placebo patches (6%) was not. There was no significant difference between the effect of the dextrose when accompanied by active versus placebo patches. There was no significant effect of dextrose on weight. The results suggest that dextrose supplementation to the diet may be a cheap and simple aid to giving up smoking. Further research is now needed to establish its long-term efficacy.

Cyclical changes in the renin-angiotensin-aldosterone system during the menstrual cycle of the baboon (Papio hamadryas)

This study characterizes the renin-angiotensin-aldosterone system during the normal menstrual cycle in the baboon. Ten animals received a daily dose of an ACE inhibitor or placebo in a randomized blind cross-over design. Data were obtained during the mid-follicular and early luteal phases of normal non-pregnant menstrual cycles. All examinations and blood collections were performed with ketamine sedation: 7-kg by im injection. Blood pressure was recorded by sphygmomanometer. Serum ACE activity was measured by spectrophotometry. Aldosterone (ALDO), angiotensin I (AI), and angiotensin II (AII) were measured by radioimmunoassay. Plasma renin activity (PRA) was measured by AI generation. The renin-angiotensin-aldosterone system was found to be activated in the follicular phase and suppressed during the luteal phase of the normal non-pregnant menstrual cycle in the baboon.

Indicators of histohypoxia

Cellular tissue damage due to inadequate oxygen supply is frequently encountered in the critically ill patient and can be the end result of a number of conditions. The eventual disruption to the normal processes required for the cell to survive can be due either to the hypoxic state per se or by damage caused during reperfusion of the tissue. Blood gas analysis is commonly used as a macro indicator of oxygen supply, state of art blood gas analysers provide information for oxygen tension (pO2), haemoglobin oxygen saturation (SO2) and concentration (THb), ideally, in arterial and mixed venous blood. The concurrent measurement of carbon dioxide tension (pCO2) and pH will allow the calculation of variables which assist in differentiating between respiratory and non-respiratory conditions. Measurement of cardiac output and clinical assessment of the patients' oxygen requirements will complete the macro picture of supply and demand and although computed indicators of hypoxia have been improved in recent years (1, 2) the definitive diagnosis of histohypoxia requires the measurement of the cellular and subcellular products of metabolic processes that are present when an inappropriate concentration of oxygen has been experienced. However, increases, for example, in blood lactate concentration can occur when an ischaemic area is reperfused and it is argued conversely, that the absence of hyperlactataemia in conditions such as acute respiratory distress syndrome does not necessarily preclude delivery dependence of oxygen consumption with the attendant potential for tissue hypoxia (3). Nevertheless there is general agreement that blood lactate levels can serve as a reliable clinical guide to therapy (4). The laboratory measurement of the metabolic products that accumulate when cellular oxygen supply is limited has become far less labour intensive and with the development of increasingly sophisticated instrumentation, these analytes can be available in small to medium hospital laboratories as well as the larger units. The relatively rapid and accurate analysis of metabolites that accumulate in hypoxic states has allowed us to measure concentrations of blood lactate, pyruvate, beta-hydroxybutyrate and acetoacetate and calculate the lactate/pyruvate ratio and beta-hydroxybutyrate/acetoacetate ratio. These measurements and ratios can then be compared with the non invasive macro blood gas indicators in order to determine their effectiveness as additional "routine" investigations and to indicate how each of the variables contributes to the eventual diagnosis. The parameters used in this study are as follows: Oxygen tension-pO2, Haemoglobin oxygen saturation-SaO2, Haemoglobin concentration-THb, Hydrogen ion concentration as-pH, Concentration of extractable oxygen-Cx, Oxygen extraction tension-px, Conditional extraction at an assumed pvO2 = 30 mmHg-C(a-30)O2, Lactate and pyruvate, beta-hydroxybutyrate and acetoacetate.

Non-invasive estimation of venous admixture: validation of a new formula

We have developed a computer program that estimates venous admixture (intra-pulmonary shunt) from four measurements: haemoglobin concentration, end-tidal carbon dioxide tension (PE'CO2), fractional inspired oxygen concentration (FIO2) and pulse oximetry (SpO2). The formula was tested on patients in an intensive therapy unit by using it to estimate shunt while it was measured simultaneously by a standard, invasive method. A total of 101 measurements were made in 29 patients. After correcting the systematic errors in the assumed differences between PE'CO2 and arterial PCO2, and between SpO2 and co-oximetrically measured SaO2, and correcting for a trend in the arteriovenous oxygen concentration difference (C(a-v))2) with shunt, the bias of the non-invasive minus invasive shunt differences was negligible, with no significant dependence on shunt. The limits of agreement were then +/- 16% shunt overall (+/- 13% within patients). When SaO2 was used instead of SpO2, the limits were +/- 11% (+/- 8% within patients).

Estimation of effective and total erythropoiesis in myelodysplasia using serum transferrin receptor and erythropoietin concentrations, with automated reticulocyte parameters

The erythroid abnormality in patients with myelodysplasia (MDS) is multifactorial, with ineffective erythropoiesis and poor in vitro progenitor response to erythropoietin (EPO). Serum EPO concentration is variable among patients for a given haemoglobin concentration. We studied 19 non-transfusion-dependent patients with MDS, and 13 healthy elderly control subjects in an attempt to define the factors governing variability in serum EPO and to further characterise the anaemia of MDS. Serum EPO concentration was appropriate for the degree of anaemia in 15/19 MDS patients, and was positively related to mean cell volume (MCV), mean cell haemoglobin (MCH), and percentage highly fluorescent reticulocytes (% HFR), but not to absolute or percentage reticulocyte count. Although the observed/predicted ratio for serum transferrin receptor (TfR) concentration was low in 12 of 19 MDS subjects, no relationship to haemoglobin concentration, reticulocytes or serum EPO was seen. Serum TfR was positively correlated with WBC and platelet counts. Serum TfR was higher in patients with sideroblastic anaemia than refractory anaemia. Standardized in vivo p50 was positively correlated to red cell 2,3 diphosphoglycerate concentration, although this was not the only factor influencing the oxygen dissociation curve. We conclude that effective erythroid output responsive to endogenous EPO drive in MDS is positively related to MCV, MCH and % HFR. Serum TfR may not represent effective output as precisely as % HFR, but may be proportional to total marrow erythropoietic activity.

Effects of the correction of renal anaemia by erythropoietin on physiological changes during exercise

The effects of treating the anaemia of end-stage renal failure with erythropoietin were studied in nine dialysis patients. The increase in haemoglobin concentration (by 59% from 7.0 +/- 1.2 to 11.1 +/- 1.1 g dl-1) was associated with increases in exercise duration (by 41%) and maximum oxygen consumption (by 34%). Treatment reduced resting heart rate but did not significantly alter heart rate at maximum exercise, nor resting or exercise blood pressure. Resting arterial potassium concentrations were slightly increased after treatment, but they increased similarly in relation to minute ventilation during exercise. Lactic acidaemia developed during exercise at both levels of haemoglobin, and was accompanied by similar reductions in arterial pH and bicarbonate levels but constant PaO2 and PaCO2. Ventilation was coupled to the metabolic rate of carbon dioxide production, ventilatory dead-space and arterial PCO2 before and after treatment of anaemia, the ventilatory requirement for carbon dioxide elimination being unchanged. Treatment of anaemia did not alter resting arterial lactate concentration; the concentration of lactate at maximum exercise was increased slightly following treatment but this increase did not reach statistical significance. The rate of increase in arterial lactate concentration as a function of oxygen consumption, assessed both with respect to the 'lactate threshold' and 'lactate slope index', was significantly delayed by treatment. Treatment of anaemia also delayed the 'anaerobic threshold', and there was good correlation between lactate and anaerobic thresholds. Treatment of renal anaemia by erythropoietin thus results in improved tissue oxygen supply during exercise, reflected by delay in the onset of lactic acidaemia.

The ventilatory cost of exercise compared in chronic heart failure and chronic renal anaemia

The cardiorespiratory responses to maximal treadmill exercise were compared in matched groups of patients with chronic renal anaemia or treated chronic heart failure, and in normal controls. Exercise capacity was similarly reduced in both patient groups compared to normal controls, the raised respiratory exchange ratio at peak exercise implying anaerobic metabolism due to limited oxygen delivery in heart failure and limited oxygen carrying capacity in anaemia. Minute ventilation (VE) was related linearly to minute CO2 production (VCO2) in all subjects (each r > 0.92) from all three groups. The slope of the VE/VCO2 relationship was normal in anaemia but steeper in heart failure, reflecting ventilation/perfusion mismatching in chronic heart failure.