Inhalational volatile anaesthetic agents: the atmospheric scientists' viewpoint

All sectors of society must reduce their carbon footprint to mitigate climate change, and the healthcare community is no exception. This narrative review focuses on the environmental concerns associated with the emissions of volatile anaesthetic agents, some of which are potent greenhouse gases. This review provides an understanding of the global warming potential metric, as well as the concepts of atmospheric lifetime and radiative efficiency. The state of knowledge of the environmental impact and possible climate forcing of emitted volatile anaesthetic agents are reviewed. Additionally, the review discusses how climate metrics can guide mitigation strategies to reduce emissions and suggests present and future options for mitigating the climate impact.

The case for a more precise definition of regulated PFAS

We argue that there is a need for a more precise of PFAS in a way that avoids including compounds with single CF₃-, -CF₂-, or CF- groups and excludes TFA and compounds that degrade to just give TFA. An example that meets this need is the definition by the U.S. Environmental Protection Agency of PFAS as "per- and polyfluorinated substances that structurally contain the unit R-(CF₂)-C(F)(R₁)R₂. Both the CF₂ and CF moieties are saturated carbons and none of the R groups (R, R₁, or R₂) can be hydrogen". Adoption of this definition, or one like it, would place future technical and regulatory discussions of the environmental impacts of organo-fluorine compounds on a sounder technical footing by focusing PFAS discussions and regulation on long-chain perfluoroalkyl sulfonic acids and perfluoroalkyl carboxylic acids.

Asparaginase-Associated Pancreatitis in Acute Lymphoblastic Leukemia: Results From the NOPHO ALL2008 Treatment of Patients 1-45 Years of Age

PURPOSE

Asparaginase-associated pancreatitis (AAP) is common in patients with acute lymphoblastic leukemia (ALL), but risk differences across age groups both in relation to first-time AAP and after asparaginase re-exposure have not been explored.

PATIENTS AND METHODS

We prospectively registered AAP (n = 168) during treatment of 2,448 consecutive ALL patients aged 1.0-45.9 years diagnosed from July 2008 to October 2018 and treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL2008 protocol.

RESULTS

Compared with patients aged 1.0-9.9 years, adjusted AAP hazard ratios (HRa) were associated with higher age with almost identical HRa (1.6; 95% CI, 1.1 to 2.3; P = .02) for adolescents (10.0-17.9 years) and adults (18.0-45.9 years). The day 280 cumulative incidences of AAP were 7.0% for children (1.0-9.9 years: 95% CI, 5.4 to 8.6), 10.1% for adolescents (10.0 to 17.9 years: 95% CI, 7.0 to 13.3), and 11.0% for adults (18.0-45.9 years: 95% CI, 7.1 to 14.9; P = .03). Adolescents had increased odds of both acute (odds ratio [OR], 5.2; 95% CI, 2.1 to 13.2; P = .0005) and persisting complications (OR, 6.7; 95% CI, 2.4 to 18.4; P = .0002) compared with children (1.0-9.9 years), whereas adults had increased odds of only persisting complications (OR, 4.1; 95% CI, 1.4 to 11.8; P = .01). Fifteen of 34 asparaginase-rechallenged patients developed a second AAP. Asparaginase was truncated in 17/21 patients with AAP who subsequently developed leukemic relapse, but neither AAP nor the asparaginase truncation was associated with increased risk of relapse.

CONCLUSION

Older children and adults had similar AAP risk, whereas morbidity was most pronounced among adolescents. Asparaginase re-exposure should be considered only for patients with an anticipated high risk of leukemic relapse, because multiple studies strongly indicate that reduction of asparaginase treatment intensity increases the risk of relapse.

Addressing the room for improvement in management of acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is highly curable. To achieve high cure rates, targeted therapy with retinoic acid (ATRA) must be started promptly at time of suspected diagnosis. Early death rates (EDRs, ≤30 days from diagnosis) differ markedly in patients treated on clinical trials compared to the general population.

OBJECTIVES AND METHODS

We used the comprehensive Danish National Acute Leukemia Registry (DNLR) to investigate the incidence, treatment, EDR, and long-term clinical outcome in APL between 2000 and 2014.

RESULTS

Twenty-two of 41 deaths occurring in 122 APL patients were EDs which were primarily caused by intracranial hemorrhage, disseminated intravascular coagulation (DIC), sepsis, and multiorgan failure. The overall EDR was 18.0%, whereas clinical trial participants had an EDR of 6.7%. Fifteen patients recruited to the NCRI AML17 APL trial from 2010 to 2013 were younger and had decreased mortality (HR 0.18, CI 0.04-0.86, P = 0.02) compared to contemporarily treated patients (n = 15) not recruited to a clinical trial. Performance status, leukemia origin, and Sanz-score were independent prognostic variables.

CONCLUSIONS

The very low EDR for on-trial patients is not observed in the general cohort of APL patients. Diagnostic awareness emerges as the greatest clinical challenge in management of APL.

Reactions of Three Lactones with Cl, OD, and O3: Atmospheric Impact and Trends in Furan Reactivity

Lactones, cyclic esters of hydroxycarboxylic acids, are interesting biofuel candidates as they can be made from cellulosic biomass and have favorable physical and chemical properties for distribution and use. The reactions of γ-valerolactone (GVL), γ-crotonolactone (2(5H)-F), and α-methyl-γ-crotonolactone (3M-2(5H)-F) with Cl, OD, and O₃ were investigated in a static chamber at 700 Torr and 298 ± 2 K. The relative rate method was used to determine k_GVL+Cl = (4.56 ± 0.51) × 10^-11, k_GVL+OD = (2.94 ± 0.41) × 10^-11, k_2(5H)-F+Cl = (2.94 ± 0.41) × 10^-11, k_2(5H)-F+OD = (4.06 ± 0.073) × 10^-12, k_{3M-2(5H)-F+Cl} = (16.1 ± 1.8) × 10^-11, and k_{3M-2(5H)-F+OD} = (12.6 ± 0.52) × 10^-12, all rate coefficients in units of cm³ molecule^-1 s^-1. An absolute rate method was used to determine k_2(5H)-F+O3 = (6.73 ± 0.18) × 10^-20 and k_{3M-2(5H)-F+O3} = (5.42 ± 1.23) × 10^-19 in units of cm³ molecule^-1 s^-1. Products were identified for reactions of the lactones with Cl. In the presence of O₂ the products are formic acid (HCOOH), formyl chloride (CHClO), and phosgene (CCl₂O), and also maleic anhydride (C₂H₂(CO)₂O) for 2(5H)-F. In addition both reactions produced a number of unidentified products that likely belong to molecules with the ring-structure intact. A review of literature data for reactions of other furans show that the reactivity of the lactones are generally lower compared to that of corresponding compounds without the carbonyl group.

A comparison of clofarabine with ara-C, each in combination with daunorubicin as induction treatment in older patients with acute myeloid leukaemia

The study was designed to compare clofarabine plus daunorubicin vs daunorubicin/ara-C in older patients with acute myeloid leukaemia (AML) or high-risk myelodysplastic syndrome (MDS). Eight hundred and six untreated patients in the UK NCRI AML16 trial with AML/high-risk MDS (median age, 67 years; range 56-84) and normal serum creatinine were randomised to two courses of induction chemotherapy with either daunorubicin/ara-C (DA) or daunorubicin/clofarabine (DClo). Patients were also included in additional randomisations; ± one dose of gemtuzumab ozogamicin in course 1; 2v3 courses and ± azacitidine maintenance. The primary end point was overall survival. The overall response rate was 69% (complete remission (CR) 60%; CRi 9%), with no difference between DA (71%) and DClo (66%). There was no difference in 30-/60-day mortality or toxicity: significantly more supportive care was required in the DA arm even though platelet and neutrophil recovery was significantly slower with DClo. There were no differences in cumulative incidence of relapse (74% vs 68%; hazard ratio (HR) 0.93 (0.77-1.14), P=0.5); survival from relapse (7% vs 9%; HR 0.96 (0.77-1.19), P=0.7); relapse-free (31% vs 32%; HR 1.02 (0.83-1.24), P=0.9) or overall survival (23% vs 22%; HR 1.08 (0.93-1.26), P=0.3). Clofarabine 20 mg/m2 given for 5 days with daunorubicin is not superior to ara-C+daunorubicin as induction for older patients with AML/high-risk MDS.

Atmospheric chemistry of short-chain haloolefins: photochemical ozone creation potentials (POCPs), global warming potentials (GWPs), and ozone depletion potentials (ODPs)

Short-chain haloolefins are being introduced as replacements for saturated halocarbons. The unifying chemical feature of haloolefins is the presence of a CC double bond which causes the atmospheric lifetimes to be significantly shorter than for the analogous saturated compounds. We discuss the atmospheric lifetimes, photochemical ozone creation potentials (POCPs), global warming potentials (GWPs), and ozone depletion potentials (ODPs) of haloolefins. The commercially relevant short-chain haloolefins CF3CFCH2 (1234yf), trans-CF3CHCHF (1234ze(Z)), CF3CFCF2 (1216), cis-CF3CHCHCl (1233zd(Z)), and trans-CF3CHCHCl (1233zd(E)) have short atmospheric lifetimes (days to weeks), negligible POCPs, negligible GWPs, and ODPs which do not differ materially from zero. In the concentrations expected in the environment their atmospheric degradation products will have a negligible impact on ecosystems. CF3CFCH2 (1234yf), trans-CF3CHCHF (1234ze(Z)), CF3CFCF2 (1216), cis-CF3CHCHCl (1233zd(Z)), and trans-CF3CHCHCl (1233zd(E)) are environmentally acceptable.

Corn ethanol production, food exports, and indirect land use change

The approximately 100 million tonne per year increase in the use of corn to produce ethanol in the U.S. over the past 10 years, and projections of greater future use, have raised concerns that reduced exports of corn (and other agricultural products) and higher commodity prices would lead to land-use changes and, consequently, negative environmental impacts in other countries. The concerns have been driven by agricultural and trade models, which project that large-scale corn ethanol production leads to substantial decreases in food exports, increases in food prices, and greater deforestation globally. Over the past decade, the increased use of corn for ethanol has been largely matched by the increased corn harvest attributable mainly to increased yields. U.S. exports of corn, wheat, soybeans, pork, chicken, and beef either increased or remained unchanged. Exports of distillers' dry grains (DDG, a coproduct of ethanol production and a valuable animal feed) increased by more than an order of magnitude to 9 million tonnes in 2010. Increased biofuel production may lead to intensification (higher yields) and extensification (more land) of agricultural activities. Intensification and extensification have opposite impacts on land use change. We highlight the lack of information concerning the magnitude of intensification effects and the associated large uncertainties in assessments of the indirect land use change associated with corn ethanol.

Atmospheric chemistry of 2-ethoxy-3,3,4,4,5-pentafluorotetrahydro-2,5-bis[1,2,2,2-tetrafluoro-1-(trifluoromethyl)ethyl]-furan: kinetics, mechanisms, and products of Cl atom and OH radical initiated oxidation

Smog chamber/FTIR techniques were used to study the atmospheric chemistry of the title compound which we refer to as RfOC2H5. Rate constants of k(Cl + RfOC2H5) = (2.70 +/- 0.36) x 10(-12), k(OH + RfOC2H5) = (5.93 +/- 0.85) x 10(-14), and k(Cl + RfOCHO) = (1.34 +/- 0.20) x 10(-14) cm3 molecule(-1') s(-1) were measured in 700 Torr of N2, or air, diluent at 294 +/- 1 K. From the value of k(OH + RfOC2H5) the atmospheric lifetime of RfOC2H5 was estimated to be 1 year. Two competing loss mechanisms for RfOCH(O*)CH3 radicals were identified in 700 Torr of N2/O2 diluent at 294 +/- 1 K; decomposition via C-C bond scission giving a formate (RfOCHO), or reaction with 02 giving an acetate (RfOC(O)CH3). In 700 Torr of N2/O2 diluent at 294 +/- 1 K the rate constant ratio k(O2)/k(diss) = (1.26 +/- 0.74) x 10(-19) cm3 molecule(-1). The OH radical initiated atmospheric oxidation of RfOC2H5 gives Rf0CHO and RfOC(O)CH3 as major products. RfOC2H5 has a global warming potential of approximately 55 for a 100 year horizon. The results are discussed with respect to the atmospheric chemistry and environmental impact of RfOC2H5.

Atmospheric chemistry of 4:2 fluorotelomer alcohol (n-C4F9CH2CH2OH): products and mechanism of Cl atom initiated oxidation in the presence of NOx

Smog chamber/FTIR techniques were used to study the Cl atom initiated oxidation of 4:2 fluorotelomer alcohol (C(4)F(9)CH(2)CH(2)OH, 4:2 FTOH) in the presence of NO(x) in 700 Torr of N(2)/O(2) diluent at 296 K. Chemical activation effects play an important role in the atmospheric chemistry of the peroxy, and possibly the alkoxy, radicals derived from 4:2 FTOH. Cl atoms react with C(4)F(9)CH(2)CH(2)OH to give C(4)F(9)CH(2)C(*)HOH radicals which add O(2) to give chemically activated alpha-hydroxyperoxy radicals, [C(4)F(9)CH(2)C(OO(*))HOH]*. In 700 Torr of N(2)/O(2) at 296 K, approximately 50% of the [C(4)F(9)CH(2)C(OO(*))HOH]* radicals decompose "promptly" to give HO(2) radicals and C(4)F(9)CH(2)CHO, the remaining [C(4)F(9)CH(2)C(OO(*))HOH]* radicals undergo collisional deactivation to give thermalized peroxy radicals, C(4)F(9)CH(2)C(OO(*))HOH. Decomposition to HO(2) and C(4)F(9)CH(2)CHO is the dominant atmospheric fate of the thermalized peroxy radicals. In the presence of excess NO, the thermalized peroxy radicals react to give C(4)F(9)CH(2)C(O(*))HOH radicals which then decompose at a rate >2.5 x 10(6) s(-1) to give HC(O)OH and the alkyl radical C(4)F(9)CH(2)(*). The primary products of 4:2 FTOH oxidation in the presence of excess NO(x) are C(4)F(9)CH(2)CHO, C(4)F(9)CHO, and HCOOH. Secondary products include C(4)F(9)CH(2)C(O)O(2)NO(2), C(4)F(9)C(O)O(2)NO(2), and COF(2). In contrast to experiments conducted in the absence of NO(x), there was no evidence (<2% yield) for the formation of the perfluorinated acid C(4)F(9)C(O)OH. The results are discussed with regard to the atmospheric chemistry of fluorotelomer alcohols.

Atmospheric chemistry of CF3CH=CH2 and C4F9CH=CH2: products of the gas-phase reactions with Cl atoms and OH radicals

FTIR-smog chamber techniques were used to study the products of the Cl atom and OH radical initiated oxidation of CF3CH=CH2 in 700 Torr of N2/O2, diluent at 296 K. The Cl atom initiated oxidation of CF3CH=CH2 in 700 Torr of air in the absence of NOx gives CF3C(O)CH2Cl and CF3CHO in yields of 70+/-5% and 6.2+/-0.5%, respectively. Reaction with Cl atoms proceeds via addition to the >C=C< double bond (74+/-4% to the terminal and 26+/-4% to the central carbon atom) and leads to the formation of CF3CH(O)CH2Cl and CF3CHClCH2O radicals. Reaction with O2 and decomposition via C-C bond scission are competing loss mechanisms for CF3CH(O)CH2Cl radicals, kO2/kdiss=(3.8+/-1.8)x10(-18) cm3 molecule-1. The atmospheric fate of CF3CHClCH2O radicals is reaction with O2 to give CF3CHClCHO. The OH radical initiated oxidation of CxF2x+1CH=CH2 (x=1 and 4) in 700 Torr of air in the presence of NOx gives CxF2x+1CHO in a yield of 88+/-9%. Reaction with OH radicals proceeds via addition to the >C=C< double bond leading to the formation of CxF2x+1C(O)HCH2OH and CxF2x+1CHOHCH2O radicals. Decomposition via C-C bond scission is the sole fate of CxF2x+1CH(O)CH2OH and CxF2x+1CH(OH)CH2O radicals. As part of this work a rate constant of k(Cl+CF3C(O)CH2Cl)=(5.63+/-0.66)x10(-14) cm3 molecule-1 s-1 was determined. The results are discussed with respect to previous literature data and the possibility that the atmospheric oxidation of CxF2x+1CH=CH2 contributes to the observed burden of perfluorocarboxylic acids, CxF2x+1COOH, in remote locations.

Atmospheric Chemistry of a Model Biodiesel Fuel, CH3C(O)O(CH2)2OC(O)CH3: Kinetics, Mechanisms, and Products of Cl Atom and OH Radical Initiated Oxidation in the Presence and Absence of NOx

Relative rate techniques were used to study the kinetics of the reactions of Cl atoms and OH radicals with ethylene glycol diacetate, CH3C(O)O(CH2)2OC(O)CH3, in 700 Torr of N2/O2 diluent at 296 K. The rate constants measured were k(Cl + CH3C(O)O(CH2)2OC(O)CH3) = (5.7 +/- 1.1) x 10(-12) and k(OH + CH3C(O)O(CH2)2OC(O)CH3) = (2.36 +/- 0.34) x 10(-12) cm3 molecule-1 s-1. Product studies of the Cl atom initiated oxidation of ethylene glycol diacetate in the absence of NO in 700 Torr of O2/N2 diluent at 296 K show the primary products to be CH3C(O)OC(O)CH2OC(O)CH3, CH3C(O)OC(O)H, and CH3C(O)OH. Product studies of the Cl atom initiated oxidation of ethylene glycol diacetate in the presence of NO in 700 Torr of O2/N2 diluent at 296 K show the primary products to be CH3C(O)OC(O)H and CH3C(O)OH. The CH3C(O)OCH2O* radical is formed during the Cl atom initiated oxidation of ethylene glycol diacetate, and two loss mechanisms were identified: reaction with O2 to give CH3C(O)OC(O)H and alpha-ester rearrangement to give CH3C(O)OH and HC(O) radicals. The reaction of CH3C(O)OCH2O2* with NO gives chemically activated CH3C(O)OCH2O* radicals which are more likely to undergo decomposition via the alpha-ester rearrangement than CH3C(O)OCH2O* radicals produced in the peroxy radical self-reaction.

Atmospheric Chemistry of n-CxF2x+1CHO (x = 1, 2, 3, 4): Fate of n-CxF2x+1C(O) Radicals

Smog chamber/FTIR techniques were used to study the atmospheric fate of n-C(x)F(2)(x)(+1)C(O) (x = 1, 2, 3, 4) radicals in 700 Torr O(2)/N(2) diluent at 298 +/- 3 K. A competition is observed between reaction with O(2) to form n-C(x)()F(2)(x)()(+1)C(O)O(2) radicals and decomposition to form n-C(x)F(2)(x)(+1) radicals and CO. In 700 Torr O(2)/N(2) diluent at 298 +/- 3 K, the rate constant ratio, k(n-C(x)F(2)(x)(+1)C(O) + O(2) --> n-C(x)F(2)(x)(+1)C(O)O(2))/k(n-C(x)F(2)(x)(+1)C(O) --> n-C(x)F(2)(x)(+1) + CO) = (1.30 +/- 0.05) x 10(-17), (1.90 +/- 0.17) x 10(-19), (5.04 +/- 0.40) x 10(-20), and (2.67 +/- 0.42) x 10(-20) cm(3) molecule(-1) for x = 1, 2, 3, 4, respectively. In one atmosphere of air at 298 K, reaction with O(2) accounts for 99%, 50%, 21%, and 12% of the loss of n-C(x)F(2)(x)(+1)C(O) radicals for x = 1, 2, 3, 4, respectively. Results are discussed with respect to the atmospheric chemistry of n-C(x)F(2)(x)(+1)C(O) radicals and their possible role in contributing to the formation of perfluorocarboxylic acids in the environment.

Atmospheric Chemistry of Perfluorinated Aldehyde Hydrates (n-CxF2x+1CH(OH)2, x = 1, 3, 4): Hydration, Dehydration, and Kinetics and Mechanism of Cl Atom and OH Radical Initiated Oxidation

Smog chamber/Fourier transform infrared (FTIR) techniques were used to measure k(Cl+C(x)F(2x+1)CH(OH)(2)) (x = 1, 3, 4) = (5.84 +/- 0.92) x 10(-13) and k(OH+C(x)F(2x+1)CH(OH)(2)) = (1.22 +/- 0.26) x 10(-13) cm(3) molecule(-1) s(-1) in 700 Torr of N(2) or air at 296 +/- 2 K. The Cl initiated oxidation of CF(3)CH(OH)(2) in 700 Torr of air gave CF(3)COOH in a molar yield of 101 +/- 6%. IR spectra of C(x)F(2x+1)CH(OH)(2) (x = 1, 3, 4) were recorded and are presented. An upper limit of k(CF(3)CHO+H(2)O) < 2 x 10(-23) cm(3) molecule(-1) s(-1) was established for the gas-phase hydration of CF(3)CHO. Bubbling CF(3)CHO/air mixtures through liquid water led to >80% conversion of CF(3)CHO into the hydrate within the approximately 2 s taken for passage through the bubbler. These results suggest that OH radical initiated oxidation of C(x)F(2x+1)CH(OH)(2) hydrates could be a significant source of perfluorinated carboxylic acids in the environment.

Acute lymphoblastic leukemia in adolescents between 10 and 19 years of age in Denmark--secondary publication

INTRODUCTION

Data seem to indicate that young adults with acute lymphoblastic leukemia (ALL) have a better survival when treated with pediatric protocols compared with adult ALL protocols. The purpose of the study was to report the clinical characteristics and outcome of all children and young adults 10-19 years of age diagnosed with ALL in Denmark between 1992 and 2001.

MATERIAL

The study includes 99 patients 10-19 years of age with ALL in Denmark during a ten year period found in the complete NOPHO (Nordic Society of Pediatric Hematology and Oncology) registry and through the Danish Cancer Registry and local pathology databases. Data were retrieved by reviewing medical charts of the patients. A total of 61 children (10-14 years) treated on pediatric protocols and 38 young adults (15-19 years) were diagnosed with ALL. Data were reported as of January 1st 2005.

RESULTS

There were no difference with respect to the distribution of T-ALL, CNS-leukemia, total white blood count and high risk chromosomal abnormalities between the two groups. There was a statistical significant lower event free survival (p<0.01) and lower overall survival (p<0.01) in young adults compared with 10-14 year-old children (0.38 vs 0.60 and 0.47 vs 0.67). There were more transplant-related deaths in the young adults. Higher treatment intensity in children may be an additional explanatory factor. Children received more prednisone, vincristine and high-dose methotrexate than young adults.

CONCLUSION

Young adult patients with ALL might benefit from therapy with pediatric NOPHO ALL protocols.

Formation of C7F15COOH (PFOA) and other perfluorocarboxylic acids during the atmospheric oxidation of 8:2 fluorotelomer alcohol

Calculations using a three-dimensional global atmospheric chemistry model (IMPACT) indicate that n-C8F17CH2CH2OH (widely used in industrial and consumer products) degrades in the atmosphere to give perfluorooctanoic acid (PFOA) and other perfluorocarboxylic acids (PFCAs). PFOA is persistent, bioaccumulative, and potentially toxic. Molar yields of PFOA depend on location and season, are in the range of 1-10%, and are of the correct order of magnitude to explain the observed levels in Arctic fauna. Fluorotelomer alcohols such as n-C8F17CH2CH2OH appear to be a significant global source of persistent bioaccumulative perfluorocarboxylic acid pollution. This is the first modeling study of the atmospheric chemistry of a fluorotelomer alcohol.

Atmospheric Chemistry of CF3OCF2CF2H and CF3OC(CF3)2H: Reaction with Cl Atoms and OH Radicals, Degradation Mechanism, Global Warming Potentials, and Empirical Relationship between k(OH) and k(Cl) for Organic Compounds

Using FTIR smog chamber techniques, k(Cl + CF3OCF2CF2H) = (2.70 +/- 0.52) x 10(-16), k(OH + CF3OCF2CF2H) = (2.26 +/- 0.18) x 10(-15), k(Cl + CF3OC(CF3)2H) = (1.58 +/- 0.27) x 10(-18) and k(OH + CF3OC(CF3)2H) = (3.26 +/- 0.95) x 10(-16) cm3 molecule(-1) s(-1) were measured. The atmospheric lifetimes of CF3OCF2CF2H and CF3OC(CF3)2H are estimated to be 27 and 216 years, respectively. Chlorine atom initiated oxidation of CF3OCF2CF2H in 700 Torr of air in the presence of NO(x) gives CF3OC(O)F in a molar yield of 36 +/- 5% and COF2 in a molar yield of 174 +/- 9%, whereas oxidation of CF3OC(CF3)2H gives CF3OC(O)CF3 and COF2 in molar yields that are indistinguishable from 100%. Quantitative infrared spectra were recorded and used to estimate global warming potentials of 3690 and 8230 (100 year time horizon, relative to CO2) for CF3OCF2CF2H and CF3OC(CF3)2H, respectively. All experiments were performed in 700 Torr of N2/O2 diluent at 296 +/- 2 K. An empirical relationship can be used to estimate the preexponential factor, which can be combined with k(298 K) to give the temperature dependence of reactions of OH radicals with organic compounds proceeding via H-atom abstraction: log(A/n) = (0.239 +/- 0.027) log(k(OH)/n) - (8.69 +/- 0.372), k(OH) is the rate constant at 298 K and n is the number of H atoms. The rates of H-atom abstraction by OH radicals and Cl atoms at 298 K from organic compounds are related by the expression log(k(OH)) = (0.412 +/- 0.049) log(k(Cl)) - (8.16 +/- 0.72). The utility of these expressions and the atmospheric chemistry of the title hydrofluoroethers are discussed.

Rituximab chimeric anti-CD20 monoclonal antibody treatment for adult refractory idiopathic thrombocytopenic purpura

Idiopathic thrombocytopenic purpura is an autoimmune disease which involves opsonization of platelets by autoantibodies directed against different surface glycoproteins, leading to their premature destruction by the reticuloendothelial system. Management of patients with refractory ITP is difficult. Recent studies have shown that rituximab, a chimeric anti-CD20 monoclonal antibody, is useful in the treatment of these patients, with overall response rates of about 50%. Most published reports have included a small number patients including case reports. The present study reports the results of a retrospective Danish multicenter study of rituximab in the treatment of adult patients with refractory ITP. Thirty-five patients (median age 52 years, range 17-82 years, 17 males) were included. One patient had immune thrombocytopenia and neutropenia. All patients had received prednisolone (Pred). Next to Pred, 25 patients had been treated with high-dose IgG, and in 16 patients a splenectomy had been performed. Sixteen patients had been treated with azathioprine. Other treatments included, e.g., cyclosporine, danazol, cyclophosphamide, vincristine, interferon, and dexamethasone. The patients were treated with a dose regimen of 375 mg/m2 i.v. approximately once weekly for 4 consecutive weeks. Six patients received a fixed dose of 500 mg disregarding their weight supplemented by 100 mg of methylprednisone i.v. or 50-100 mg of Pred given as premedication together with an antihistamine just before infusion of rituximab. The large majority of patients also received Pred and, in some cases, other concomitant immunosuppressive treatment during part of their rituximab treatment. A complete response (CR) was defined as a rise in the platelet count > 100 x 10(9)/L, a partial response (PR) as a rise in the platelet count > 50 x 10(9)/L, and a minor response (MR) as a rise in the platelet count < 50 x 10(9)/L. No response (NR) was defined as no increase in the platelet count. Because 4 patients were treated twice, a total of 39 outcomes of rituximab treatment were evaluated. Rituximab proved to be effective in 17 of 39 treatments [overall response 44% with 7 CR (18%) (1 patient showed a CR twice), 6 PR (15%), and 4 MR (10%)]. In 9/13 cases of CR or PR, the response (platelet level > 50 x 10(9)/L) was prompt, 1-2 weeks after the first infusion. The remaining patients responded 3-8 weeks later. Patients with CR and PR have been in remission for a median of 47 weeks. In general the side effects were few. In 2 cases, the treatment was stopped because of side effects either during or after the first infusion. Two fatal outcomes were recorded. A 71-year-old female with severe lung disease died 6 days after the first infusion of respiratory failure. The other patient, a 73-year-old man also with severe chronic obstructive lung disease, died of pneumonia approximately 13 weeks following the last rituximab treatment. It is concluded that rituximab may be a useful alternative therapy in patients with severe and symptomatic ITP refractory to conventional treatment.

Anagrelide treatment in 52 patients with chronic myeloproliferative diseases

In this retrospective multi-centre study, we report our experience with anagrelide in the treatment of thrombocytosis in patients with chronic myeloproliferative diseases. Our study included 52 patients (age 20-78 years). The initial anagrelide dose was, in general, 0.5 mg once daily and mean maintenance dosage was 1.7 mg/day. The overall response rate was 79% including 75% complete remission and 4% partial remission. Forty-two patients (81%) had adverse effects and in 29% of the study population, the adverse effects necessitated cessation of anagrelide. The most common adverse effect was moderate anaemia (50%). Two patients experienced erectile dysfunction which has been described only once previously in association with anagrelide treatment. One patient progressed to acute leukaemia. However, this patient had been pre-treated with two potentially leukaemogenic drugs and had only been in short-term treatment with anagrelide. Furthermore, a total of 13 events were recorded. More than 25% of these events occurred in patients with platelet counts between 400 and 600 x 10(9)/l and almost 40% of all events occurred in patients with platelet counts above 400 x 10(9)/l. This observation supports the hypothesis that aggressive control of thrombocytosis to a platelet count <400 x 10(9)/l might reduce the number of thrombohaemorrhagic events. Anagrelide is safe and effective in reducing the platelet counts, but a high proportion of the patients discontinue treatment because of the adverse effects of the drug.

Isotopic processes in atmospheric chemistry

Trace gases are responsible for the atmospheric processes underlying air pollution and global change. Analysis of the distribution of stable isotopes in these gases is a way of gaining additional knowledge that may not otherwise be available. This approach requires knowledge of the isotopic signature of emissions sources and chemical reactions. This review focuses on the chemical physics of the processes underlying the distribution of stable isotopes in atmospheric gases.

Increased circulating platelet-leukocyte aggregates in myeloproliferative disorders is correlated to previous thrombosis, platelet activation and platelet count

Platelet-leukocyte adhesion may occur as a consequence of platelet activation and possibly plays a key role in the deposition of activated platelets and fibrin in the thrombotic plug. The aim of the present study was to assess by whole blood flow cytometry the presence of circulating platelet-leukocyte aggregates (PLA) and the platelet-leukocyte response to platelet agonist stimulation (ADP and TRAP) in 50 patients with chronic myeloproliferative disorders (MPD) and 30 controls. PLA were identified as platelet-granulocyte/monocyte aggregates (PGMA), platelet-monocyte aggregates (PMA) and defined as the percentage of leukocytes coexpressing the platelet-specific marker glycoprotein Ib. Compared to controls the mean percentage of PGMA and PMA was increased in unstimulated whole blood from patients with MPD (7.98 vs. 1.76%; p<0.001 and 12.34 vs. 3.2%; p<0.001, respectively). The percentage of PGMA was correlated to the platelet count (r=0.46; p<0.001), percentage of P-selectin (r=0.69; p<0.001) and thrombospondin (r=0.58; p<0.001) positive platelets and platelet expression of GPIV (r=0.33; p=0.02). The mean percentage of PGMA and PMA was significantly increased in ADP-stimulated whole blood of patients (57.14 vs. 47.92%; p=0.009 and 54.91 vs. 45.89%; p<0.001, respectively). Compared to patients without a history of thrombosis, patients having experienced microvascular disturbances or a thrombotic event had a higher mean percentage of PGMA and PMA in non-stimulated whole blood (10.07 vs. 6.34%; p=0.025 and 14.81 vs. 10.48%; p=0.021, respectively) and a higher percentage of PGMA in ADP stimulated whole blood (64.32 vs. 51.50%; p<0.01). These data document an increased frequency of PLA in non-stimulated whole blood in MPD associated with a previous history of thrombosis or microvascular disturbances.

Sustained remission of platelet counts following monoclonal anti-CD20 antibody therapy in two cases of idiopathic autoimmune thrombocytopenia and neutropenia

Idiopathic autoimmune thrombocytopenia and neutropenia (ITN) is a primary haemocytopenic disorder clinically characterised by recurrent mucocutaneous bleeding episodes and infections. Unlike in simple idiopathic thrombocytopenic purpura, the platelet deficiency of ITN tends to be chronic and difficult to treat. We describe two patients with ITN who obtained sustained remission of their platelet counts after therapy with the chimeric monoclonal anti-CD20 antibody Rituximab. In one of two cases, Rituximab also induced prolonged normalisation of the neutrophil count and disappearance of auto-antibodies. Our observations indicate that disturbed B-cell function plays a central role in the pathogenesis of ITN. Anti-CD20 antibody therapy seems to constitute a safe and efficient alternative to corticosteroids for the management of ITN patients with chronic thrombocytopenia.

[The chronic Philadelphia chromosome-negative myeloproliferative syndrome II. Clinical findings, diagnostics and treatment]

Polycythaemia vera (PV) and essential thrombocytosis (ET) are clinically characterised by non-specific neurologic symptoms, peripheral circulatory disturbances (acrocyanosis, wounds, erythromelalgia) or abdominal symptoms. The treatment of PV includes phlebotomy, antiaggregation and cytoreduction. In ET, the primary treatment is also low-dose aspirin except for patients presenting with a haemorrhagic diathesis. Hydroxyurea may be associated with an increased risk of acute leukaemia or myelodysplasia. Therefore alpha-interferon and anagrelide should be considered in younger patients. Early cytoreductive therapy is advocated in patients with idiopathic myelofibrosis (IMF) to inhibit further progression of bone marrow fibrosis and further expansion of myeloid metaplasia in the spleen and liver. Treatment with androgens (danazol) and glucocorticoids may improve severe anaemia and thrombocytopenia. In younger patients, allogeneic bone marrow transplantation should be considered.

[Acute thrombotic complication at the debute of the Philadelphia chromosome-negative myeloproliferative syndrome]

METHODS

We describe eight patients with a diagnosis of a chronic myeloproliferative disorder, characterised in most patients by severe thrombotic complications at the debut of the disease.

RESULTS

The symptoms were life-threatening in seven patients: acute upper gastrointestinal haemorrhage from oesophageal varices in four, an acute abdominal catastrophy owing to mesenteric vein thrombosis with intestinal gangrene in two, and a large cerebral infarction, which was lethal, in one. The same patient also suffered a thrombosis of the axillary and subclavian veins. Neurological symptoms, with headache, visual disturbances, dizziness, and impaired memory, were initial cardinal symptoms. In two patients, explorative laparotomy was performed with intestinal resection owing to gangrene. One patient had a toe amputation.

DISCUSSION

The above symptoms are explained by thrombosis in the microcirculation because of thrombocytosis and circulating platelet aggregates. In patients with polycythaemia vera, the elevated haematocrit contributes significantly to the impaired microcirculation. Early diagnosis and management of these disorders are of utmost importance to prevent the potentially life-threatening complications described above.

[The chronic Philadelphia chromosome-negative myeloproliferative syndrome I. Pathogenesis and pathophysiology]

In polycythaemia vera (PV) the erythroid progenitors proliferate autonomously independently of the circulating erythropoietin. The progenitors are hypersensitive to various growth factors, including insulin-like growth factor 1, which inhibits apoptosis in erythroid and myeloid progenitor cells. No change has been found in the erythropoietin (EPO) receptor. Thrombopoietin (Tpo) regulates the production of haematopoietic progenitor cells, particularly of platelets. By inhibiting apoptosis, this growth factor may be responsible for the autonomous proliferation of the megakaryocyte cell lineage in PV and idiopathic myelofibrosis (IMF), which are featured by highly elevated circulating Tpo levels. Thrombopoietin may also be involved in the pathogenesis of myelofibrosis and development of extramedullary haematopoiesis. Both fibrogenesis and angiogenesis in the bone marrow, spleen, and liver develop secondary to the release of various growth-promoting factors from the megakaryocyte cell lineage. The lesion of the pluripotent stem cell in PV and IMF seems to imply several defects, including lack of or decreased expression of the Tpo receptor, alterations in the sensitivity of progenitor cells to various growth factors, and alterations in important gene systems (Bcl-2), which govern cell survival. Essential thrombocytosis seems to be a heterogeneous disease entity, as about 50% of the patients have polyclonal haematopoiesis.

[Anterior screw fixation of fractures of the dens axis]

INTRODUCTION

The aim of the present study was to evaluate the results of anterior screw fixation in the treatment of odontoid fracture.

MATERIALS AND METHODS

The clinical and radiographic records of the first 14 patients treated with anterior screw fixation for odontoid fracture were reviewed retrospectively.

RESULTS

Satisfying stabilisation of the fracture was achieved in 10 patients (71%). In four patients, two of whom had severe osteoporosis, additional posterior C1/C2 fusion, owing to failure of screw treatment was needed. Two patients developed small occipital bedsores caused by preoperative treatment, but no further complications were observed.

CONCLUSION

Although only a few patients were entered in the study, the results justify the use of anterior screw fixation as the treatment of odontoid fracture in selected patients.

High prevalence of hyperhomocysteinemia due to marginal deficiency of cobalamin or folate in chronic myeloproliferative disorders

Hyperhomocysteinemia is an established risk factor for thrombosis. In patients with myeloproliferative disorders, thrombotic events are common. Our aim was to investigate whether the increased burden of proliferating cells present in these patients implies a risk of homocysteine (HCY) accumulation secondary to depletion of folate and/or cobalamin. Fifty patients (PV, 25; ET, 10; IMF, 15) and 163 healthy volunteers (HV) participated in the study. The prevalence of hyperhomocysteinemia was 56.0% in PV, 70.0% in ET, 60.0% in IMF, and 34.9% in HV. The mean P-homocysteine (P-HCY) was 13.88 +/- 4.24 micromol/L in PV, 12.78 +/- 3.70 in ET, 11.34 +/- 4.22 in IMF, and 9. 71 +/- 2.76 in HV. In PV and ET, but not in IMF, the mean P-HCY was significantly higher than in the HV group (P < 0.001, P = 0.028, and P = 0.163, respectively). Thirty-three percent of the patients with hyperhomocysteinemia displayed metabolic changes compatible with cobalamin deficiency (P-HCY and P-methylmalonic acid both elevated), while 67% were folate deficient (P-HCY elevated, P-methylmalonic acid normal). Supplementation therapy with the relevant vitamin was implemented in 11 vitamin-deficient patients and led to normalization of metabolite levels in all cases. No correlation between hyperhomocysteinemia and thrombosis was found. Our data indicate that patients with PV, ET, and IMF frequently develop hyperhomocysteinemia due to discrete depletion of cobalamin or folate. Vitamin therapy leads to normalization of P-HCY and should be considered, even though hyperhomocysteinemia does not seem to be of crucial importance for the thrombotic tendency in the myeloproliferative disorders.

Incidence, clinical features and outcome of essential thrombocythaemia in a well defined geographical area

In an attempt to characterise the clinical features, incidence and outcome of essential thrombocythaemia (ET) we report our experience in a large unselected series of patients from a well defined region. All new cases of ET in the County of Copenhagen were registered during the period 1977-98. We identified 96 cases of ET, yielding an age- and sex-adjusted annual incidence rate of 0.59/100.000 and a point-prevalence at last follow up of 11/100.000. The overall incidence rate was 0.31 and 1.00 per 100.000 population during the consecutive periods 1977-89 and 1990-98, respectively, corresponding to a 3.2-fold increase. Median age at diagnosis was 67 yr (females 68 yr, males 66 yr, range 18-87 yr), and the female to male (F/M) ratio was 2.6:1. At diagnosis, 52% of the patients displayed no ET-related symptoms and were discovered fortuitously by a routine platelet count. Forty-eight percent presented with thrombohaemorrhagic phenomena, of which microvascular disturbances of the central nervous system (CNS), extremities and skin were most frequently observed (23%). Compared to patients diagnosed after 1989, patients diagnosed before 1990 had a significantly higher mean platelet count, white blood cell (WBC) count, lactate dehydrogenase (LDH) value and alkaline phosphatase value. With a median follow up of 70 months, 5-yr survival was 76%, significantly lower than the expected survival of an age- and sex-matched control group (p = 0.0052). Thirty-seven patients experienced a total of 55 thrombohaemorrhagic events during follow-up, corresponding to an incidence of thrombosis and microvascular disturbances or haemorrhage of 8.1% per pt-yr and 2.5% per pt-yr, respectively. The number of patients experiencing thrombosis or microvascular disturbances was significantly higher among the 29 patients who never received acetylsalicylic acid (ASA) compared to the 67 patients who received ASA during follow up (45% vs. 21%; p = 0.017). This study provides population-based data suggesting the benefit of treatment with low-dose ASA in a non-selected population of patients with ET.

Increased platelet activation and abnormal membrane glycoprotein content and redistribution in myeloproliferative disorders

Chronic myeloproliferative disorders (MPDs) are characterized by a high incidence of thrombohaemorrhagic complications, possibly caused by platelet dysfunction. In an attempt to define platelet functional abnormalities, we assessed the expression of activation-dependent membrane proteins in unstimulated and agonist [ADP and thrombin receptor-activating peptide (TRAP)]-stimulated platelets using quantitative whole blood flow cytometry in samples from 50 MPD patients and 30 controls. The receptor densities of activation markers and glycoproteins (GPs) were quantified using standardized fluorescent beads. Compared with controls, the mean percentage of P-selectin-positive (15.3% vs. 7.2%; P < 0.001) and thrombospondin (TSP)-positive (6.6% vs. 3.7%; P = 0.003) platelets was increased in unstimulated platelets from patients. Patients having experienced a thrombotic event had a higher mean percentage of TSP-positive non-stimulated platelets than patients without a history of thrombosis (9.0% vs. 4.6%; P = 0.02) and a higher GPIV molecules of equivalent fluorochrome (MEF) value (33113 vs. 24471 MEF; P = 0.02). Mean MEF values of monoclonal antibodies (mAbs) against GPIb (34055 vs. 38945 MEF; P < 0.001) and GPIIb/IIIa (1416 vs. 1648 MEF; P < 0. 001) were significantly reduced among patients, whereas surface expression of GPIV was increased in patients (28273 vs. 16258 MEF; P < 0.001). In TRAP (10 micromol/l) stimulated whole blood, the MEF of P-selectin (9611 vs. 13293 MEF; P = 0.004) and CD63 (2385 vs. 5177 MEF; P < 0.001) and the ratio of PAC-1/GPIIb/IIIa MEF (0.98 vs. 2. 00; P < 0.001) was reduced in patients, indicating either a reduced granule GP content or an intrinsic cellular defect in receptor-mediated granule secretion and activation of the GPIIb/IIIa complex. Expressed as the relative change of MEF compared with unstimulated platelets, TRAP induced decrease of GPIb (7.8% vs. 45%; P < 0.001) and increase of GPIIb/IIIa (49.1% vs. 95.7%; P < 0.001) and GPIV expression (17.8% vs. 55.2%; P < 0.001) was attenuated in patients.

Fatal virus-associated hemophagocytic syndrome associated with coexistent chronic active hepatitis B and acute hepatitis C virus infection

A 28-year-old man was admitted to our department with intermittent fever, hepatosplenomegaly and pancytopenia. Liver parameters and serum ferritin were markedly elevated. Bone marrow biopsy showed hypocellularity, histiocytic hyperplasia, and hemophagocytosis consistent with a virus-associated hemophagocytic syndrome (VAHS). There was serological evidence of chronic active hepatitis B and acute hepatitis C virus infection. The patient died despite aggressive immunosuppressive and supportive treatment. Autopsy revealed signs of acute viral hepatitis with cholestasis. Histiocytes engaged in hemophagocytosis were observed in bone marrow and spleen. The condition was interpreted as VAHS associated with chronic active hepatitis B and acute hepatitis C virus infection. To our knowledge this is the first report of a hemophagocytic syndrome in that setting.

[The effect of traditional Chinese acupuncture on severe tinnitus. A double-blind, placebo-controlled clinical study with an open therapeutic surveillance]

The aim of the present study was to determine the effect of intensive acupuncture on severe tinnitus. The structure of the study was a randomized, double-blind, clinical investigation with open therapeutic surveillance and included 54 patients. All were subjected to 25 treatment sessions over a period of two months, each treatment lasting 30 minutes. Fifty-two patients completed the study. The variables used for self-registration were based on the Visual Analogue Scale, where annoyance, loudness and awareness of the tinnitus were assessed. These were recorded twice daily over a four month period starting one month before the first treatment and ending one month after the last treatment. Questionnaires, interviews and audiometry were carried out repeatedly. No statistically significant differences were found between the acupuncture group and the placebo group.

[Virus-associated hemophagocytic syndrome. Diagnosis and treatment]

Virus-associated haemophagocytic syndrome (VAHS) is a rare disease characterized by fever, splenomegaly, cytopenia and histiocytic proliferation with haemophagocytosis in the reticuloendothelial system. The clinical course of VAHS can be dramatic and the prognosis is often poor. The pathogenesis of VAHS is not well understood. Many believe that viral infection provokes an abnormal immune response in predisposed individuals leading to hyperactivation of Th1 helper cells, macrophage proliferation and secretion of large amounts of cytokines. The resultant hypercytokinaemia may be responsible for the clinical and biochemical manifestations of VAHS. In this article the clinical features, presumed pathogenesis, diagnostic criteria and treatment of VAHS are discussed.

Serum erythropoietin during normal pregnancy: relationship to hemoglobin and iron status markers and impact of iron supplementation in a longitudinal, placebo-controlled study on 118 women

Serum erythropoietin (EPO) and its relationship to hemoglobin (Hb), iron status markers and iron supplementation during normal pregnancy was assessed in a longitudinal, placebo-controlled study on 118 women, 61 took daily tablets containing 66 mg ferrous iron from the second trimester until delivery and 57 took placebo. Blood samples were obtained at 4-week intervals until delivery as well as post-partum. In the placebo-treated women, median serum EPO rose from 22.5 U/l at inclusion to 35.0 U/l at delivery (P = 0.0001). In the iron-treated women, median serum EPO rose from 23.9 to 29.9 U/l (P = 0.0001). Serum EPO showed a steeper increase in the placebo-treated women than in the iron-treated women (P < 0.05). After delivery, serum EPO became normal in both groups (P = 0.0001). Median Hb was lower in placebo-treated (iron depleted) than in iron-treated (iron repleted) women (P < 0.05). In the placebo-treated women there was a negative correlation and in the iron-treated women a positive correlation between serum EPO and Hb. In the placebo-treated women, inverse correlations existed between serum EPO and serum transferrin saturation and serum ferritin, reflecting the consequences of iron deficiency, whereas the iron-treated women displayed no correlation. A physiological, nonhypoxia-induced increase in EPO production accounts for the basic expansion of the red cell mass during pregnancy. In placebo-treated women, iron deficient erythropoiesis constitutes an additional hypoxic stimulus, which induces a further increase in serum EPO.

Human erythropoietin response to hypocapnic hypoxia, normocapnic hypoxia, and hypocapnic normoxia

This study investigated the human erythropoietin (EPO) response to short-term hypocapnic hypoxia, its relationship to a normoxic or hypoxic increase of the haemoglobin oxygen affinity, and its suppression by the addition of CO2 to the hypoxic gas. On separate days, eight healthy male subjects were exposed to 2 h each of hypocapnic hypoxia, normocapnic hypoxia, hypocapnic normoxia, and normal breathing of room air (control experiment). During the control experiment, serum-EPO showed significant variations (ANOVA P = 0.047) with a 15% increase in mean values. The serum-EPO measured in the other experiments were corrected for these spontaneous variations in each individual. At 2 h after ending hypocapnic hypoxia (10% O2 in nitrogen), mean serum-EPO increased by 28% [baseline 8.00 (SEM 0.84) U.l-1, post-hypoxia 10.24 (SEM 0.95) U.l-1, P = 0.005]. Normocapnic hypoxia was produced by the addition of CO2 (10% Co2 with 10% O2) to the hypoxic gas mixture. This elicited an increased ventilation, unaltered arterial pH and haemoglobin oxygen affinity, a lower degree of hypoxia than during hypocapnic hypoxia, and no significant changes in serum-EPO (ANOVA P > 0.05). Hypocapnic normoxia, produced by hyperventilation of room air, elicited a normoxic increase in the haemoglobin oxygen affinity without changing serum-EPO. Among the measured blood gas and acid-base parameters, only the partial pressures of oxygen in arterial blood during hypocapnic hypoxia were related to the peak values of serum-EPO (r = -0.81, P = 0.01). The present human EPO responses to hypoxia were lower than those which have previously been reported in rodents and humans. In contrast with the earlier rodent studies, it was found that human EPO production could not be triggered by short-term increases in pH and haemoglobin oxygen affinity per se, and the human EPO response to hypoxia could be suppressed by concomitant normocapnia without acidosis.

Cord serum erythropoietin in 90 healthy newborn term infants: relationship to blood gases and iron status markers

In this study, we examined the cord serum erythropoietin (EPO) level in newborn infants in relation to venous cord blood gases and iron status markers (cord serum ferritin, cord serum transferrin saturation). The subjects were 90 healthy newborn term infants with a normal birth and 90 healthy women with an uncomplicated pregnancy and delivery. Within 14-18 weeks of gestation, 47 prospective mothers, allocated at random, received tablets containing 66 mg ferrous iron daily, and 43 received a placebo. Serum EPO was measured in women prior to delivery. Serum EPO, serum ferritin and serum transferrin saturation were analyzed in cord blood from the newborn. Blood gases (PO2, PCO2 and standard HCO3, PH) were measured in venous cord blood and Apgar scores were recorded. The cord serum EPO level in the newborn was not significantly affected by the iron supplementation to the mothers. In the entire series, the geometric mean cord serum EPO was 36 U/I, (median 32 U/I, 5-95% 16-150, range 12-380). There was no correlation between cord serum EPO and APgar score, cord blood PO2, PCO2, standard HCO3 and pH. In the newborn of placebo-treated mothers, log cord serum EPO was inversely correlated with log cord serum ferritin (r = -0.54, P < 0.0002) and cord serum transferrin saturation (r = -0.39, P < 0.011), suggesting that iron deficiency may occur in this newborn group.

Diurnal variations of serum erythropoietin at sea level and altitude

This study tested the hypothesis that the diurnal variations of serum-erythropoietin concentration (serum-EPO) observed in normoxia also exist in hypoxia. The study also attempted to investigate the regulation of EPO production during sustained hypoxia. Nine subjects were investigated at sea level and during 4 days at an altitude of 4350 m. Median sea level serum-EPO concentration was 6 (range 6-13) U.l-1. Serum-EPO concentration increased after 18 and 42 h at altitude, [58 (range 39-240) and 54 (range 36-340) U.l-1, respectively], and then decreased after 64 and 88 h at altitude [34 (range 18-290) and 31 (range 17-104) U.l-1, respectively]. These changes of serum-EPO concentration were correlated to the changes in arterial blood oxygen saturation (r = -0.60, P = 0.0009), pH (r = 0.67, P = 0.003), and in-vivo venous blood oxygen half saturation tension (r = -0.68, P = 0.004) but not to the changes in 2, 3 diphosphoglycerate. After 64 h at altitude, six of the nine subjects had down-regulated their serum-EPO concentrations so that median values were three times above those at sea level. These six subjects had significant diurnal variations of serum-EPO concentration at sea level; the nadir occurred between 0800-1600 hours [6 (range 4-13) U.l-1], and peak concentrations occurred at 0400 hours [9 (range 8-14) U.l-1, P = 0.02]. After 64 h at altitude, the subjects had significant diurnal variations of serum-EPO concentration; the nadir occurred at 1600 hours [20 (range 16-26) U.l-1], and peak concentrations occurred at 0400 hours [31 (range 20-38) U.l-1, P = 0.02]. This study demonstrated diurnal variations of serum-EPO concentration in normoxia and hypoxia, with comparable time courses of median values. The results also suggested that EPO production at altitude is influenced by changes in pH and haemoglobin oxygen affinity.

[Renaissance of the reticulocyte]

Flowcytometric enumeration of reticulocytes using RNA-binding fluorochromes, a method both sensitive and reproducible, is rapidly gaining ground. It performs conspicuously better than the traditional manual method of reticulocyte counting, which is unacceptably inaccurate. The reticulocyte count is a valuable indicator of erythropoietic activity, of essential importance in discerning between the aregeneratory anaemias and anaemias accompanied by an adequate, partial or complete compensatory erythropoietic response. The reticulocyte count can be applied to the monitoring of the response to treatment including both allogeneic and autologous bone marrow transplantation, as well as to the evaluation of the response to recombinant human growth factors. The mean fluorescence intensity of reticulocytes enumerated by the flowcytometric analysis, is a variable possessing an independent clinical value for calculation of a reticulocyte production index and an erythropoiesis index.