Products of the OH radical-initiated reaction of 3-hexene-2,5-dione

3-Hexene-2,5-dione [CH3C(O)CH=CHC(O)CH3] and other unsaturated 1,4-dicarbonyls are formed from the atmospheric photooxidations of aromatic hydrocarbons. We have investigated the products of the gas-phase reaction of OH radicals with 3-hexene-2,5-dione in the presence of NO at room temperature and atmospheric pressure of air using in situ atmospheric pressure ionization tandem mass spectrometry. Products of molecular weight 102 and 191 were identified and from consideration of the potential reactions these are attributed to CH3C(O)CH(OH)CHO and CH3C(O)CH(OH)CH(ONO2)C(O)CH3, respectively. After initial addition of the OH radical, the CH3C(O)CH(OH)(*C)HC(O)CH3 radical adds O2 to form the peroxy radical which reacts with NO to yield the molecular weight 191 hydroxynitrate CH3C(O)CH(OH)CH(ONO2)C(O)CH3 or the hydroxyalkoxy radical CH3C(O)CH(OH)CH(*O)C(O)CH3 plus NO2. Our observation of a molecular weight 102 species indicates that the CH3C(O)CH(OH)CH(*O)C(O)CH3 radical dominantly decomposes to CH3C(O)CH(OH)CHO plus CH3(*C)O, rather than decomposing to CH3C(O)CHO plus CH3C(O)(*C)HOH, isomerizing, or reacting with O2. Thermochemical calculations and an empirical estimation method for calculating alkoxy radical reaction rates are consistent with our experimental observations.

Kinetic and product studies of the reactions of selected glycol ethers with OH radicals

Glycol ethers are widely used as solvents and are hence liable to be released into the atmosphere where they may contribute to the formation of photochemical air pollution in urban and regional areas. The dominant reaction of glycol ethers in the atmosphere has been previously shown to be with OH radicals. Using a relative rate method, rate constants have been measured at 296+/-2 K for the gas-phase reactions of the OH radical with 1-butoxy-2-propanol [CH3CH2CH2CH2OCH2CH(OH)CH3], diethylene glycol ethyl ether [CH3CH2OCH2CH2OCH2CH2OH], and diethylene glycol n-butyl ether [CH3CH2CH2CH2OCH2CH2OCH2-CH2OH] of (in units of 10(-11) cm3 molecule(-1) s(-1)) 3.76+/-0.54, 5.72+/-0.85, and 7.44+/-0.94, respectively, where the error limits include the estimated overall uncertainties in the rate constants for the reference compounds. Products of the OH radical-initiated reactions of these glycol ethers have been investigated using gas chromatography with flame ionization detection (GC-FID), combined gas chromatography-mass spectrometry (GC-MS), in situ Fourier transform infrared (FT-IR) spectroscopy, and in situ atmospheric pressure ionization tandem mass spectrometry (API-MS). The products identified and quantified account for 102+/-11% of the reaction products from 1-butoxy-2-propanol, 87+/-9% of those from diethylene glycol ethyl ether, and 83+/-12% of those from diethylene glycol n-butyl ether. An empirical estimation method for calculating reaction rates of alkoxy radicals under atmospheric conditions appears to fairly well predict the products formed and their yields. Detailed reaction schemes after the initial OH radical reactions are formulated for each of these glycol ethers, with the majority of the reactions involving H-atom abstraction from the CH2 groups adjacent to the ether linkage.

Atmospheric lifetimes and fates of selected fragrance materials and volatile model compounds

Fragrance materials are semivolatile organic compounds widely used in consumer products. Despite their generally low volatility, it is expected that a fraction of these compounds will volatilize into the atmosphere, where they can photolyze, react with OH radicals, NO3 radicals and O3, and/or undergo wet and dry deposition. Using relative rate methods, rate constants have been measured at 296 +/- 2 K for the gas-phase reactions of OH radicals, NO3 radicals, and 03 with the fragrance materials 1-(1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethyl-2-naphthalenyl)ethanone (OTNE), acetyl cedrene [(3R-(3a,3ab,7b,8aa))-1-(2,3,4,7,8,8a-hexahydro-3,6,8,8-tetramethyl-1H-3a,7-methanoazulen-5-yl)ethan-1-one], and HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethycyclopenta-[gamma]-2-benzopyran) as well as with isochroman which is structurally related to HHCB. Measured rate constants (in cm3 molecule(-1) s(-1) units) are OH radical reactions [OTNE, (9.85 +/- 0.88) x 10(-11); acetyl cedrene, (7.7 +/- 1.6) x 10(-11); HHCB, (2.6 +/- 0.6) x 10(-11); and isochroman, (3.7 +/- 0.6) x 10(-11)], NO3 radical reactions [OTNE, (1.71 +/- 0.19) x 10(-11) and acetyl cedrene, (4.1 +/- 1.0) x 10(-15)], and O3 reactions [OTNE, (2.1 +/- 0.5) x 10(-18) and acetyl cedrene, <2.2 x 10(-18)] where the error limits are two least-squares standard deviations. Rate constants for the OH radical reactions predicted by a structure-reactivity estimation method agree well with the measured values. The dominant tropospheric loss processes for the compounds studied are calculated to be in a reaction with OH radicals during daytime and, for OTNE and acetyl cedrene, with NO3 radicals during nighttime. The calculated atmospheric lifetimes due to daytime reaction with the OH radical are a few hours or less for the fragrance materials studied and indicate that these specific compounds will not undergo long-range transport in the atmosphere.

Peripheral blood stem cell transplantation in multiple sclerosis with busulfan and cyclophosphamide conditioning: report of toxicity and immunological monitoring

Multiple sclerosis (MS) is an immune-mediated disease that may be amenable to high-dose immunosuppression with peripheral blood stem cell transplantation (SCT) in selected patients. Five MS patients (all women, ages 39-47 years) received granulocyte colony-stimulating factor (G-CSF) for stem cell mobilization, CD34 cell selection for T-cell depletion, a preparatory regimen of busulfan (1 mg/kg x 16 doses) and cyclophosphamide (120 mg/kg), and antithymocyte globulin (10 mg/kg x 3 doses) at the time of stem cell infusion. Days required to recover absolute neutrophil count >500 were 12 to 14 and platelet count >20,000 were 17 to 58. Posttransplantation infectious complications in the first year after SCT occurred in 3 of 5 patients, and 1 patient died at day 22 after SCT from influenza A pneumonia. Neuropathologic study in this patient showed demyelinating plaques with surrounding macrophages but only rare T cells. In 2 patients, MS flared transiently with G-CSF. Magnetic resonance imaging gadolinium enhancement was present in 3 of 5 patients before transplantation and 0 of 4 after SCT. There were cerebrospinal fluid oligoclonal bands at 1 year after SCT, similar to the pretransplantation assays. Sustained suppression of peripheral blood mononuclear cell proliferative responses to myelin antigens occurred after SCT, but new responses to some myelin peptide fragments also developed after SCT. In 1 patient, enzyme-linked immunospot (ELISPOT) assays done 9 months after SCT showed a predominant T helper 2 (Th2) cytokine pattern. Neurological progression of 1 point on the extended disability status scale was seen in 1 patient 17 months after SCT. Another patient who was neurologically stable died abruptly 19 months after SCT from overwhelming S. pneumoniae sepsis. The remaining patients have had stable MS (follow-up, 18 and 30 months). In summary, our experience confirms the high-risk nature of this approach. Further studies and longer follow-up would be needed to determine the significance of new lymphocyte proliferative responses after SCT and the overall effect of this treatment on the natural history of MS.

Differential success in northwards range expansion between ecotypes of the marble gallwasp Andricus kollari: a tale of two lifecycles

The Marble gallwasp Andricus kollari has a native range divided into two geographically separated lifecycles. In Eastern Europe and Turkey, the lifecycle involves a sexual generation on Turkey oak, Quercus cerris, while in Iberia and North Africa the sexual generation host is cork oak, Q. suber. Over the last 500 years, A. kollari has expanded its range into northern Europe, following human planting of Q. cerris from Italy and the Balkans. We ask: (i) what is the genetic relationship between eastern and western distributions of Andricus kollari? Can we determine which lifecycle is ancestral, and how long ago they diverged? (ii) To what extent have eastern and western native ranges contributed to northwards range expansion? (iii) Is there any evidence for hybridization between the two life cycle types? We present analyses of allozyme data for 13 polymorphic loci and of sequence variation for a 433 bp fragment of the mitochondrial cytochrome b gene. These show: (i) that four haplotype lineages (one in Spain, two in Hungary/Italy and one in Turkey) diverged more or less simultaneously between 1 and 2 million years ago, suggesting the existence of at least four refuges through recent ice age cycles. Our data cannot resolve which lifecycle type is ancestral. (ii) Populations north of putative refuges are divided into two sets. Populations in south-west France are allied to Spain, while all remaining populations in northern Europe have been colonized from Italy and the Balkans. (iii) The transition from one race to another in south-west France is marked by abrupt transitions in the frequency of refuge-specific private alleles and corresponds closely to the northern limit of the distribution of cork oak. Although hybrids were detected in north-west France, none were detected where the two lifecycles meet in south-western France. The biology of oak gallwasps predicts that any hybrid zone will be narrow, and limited to regions where Q. cerris and Q. suber meet. Our data suggest that eastern and western A. kollari are effectively separate species.

Docetaxel-carboplatin as first line chemotherapy for epithelial ovarian cancer

A prospective, non-randomized, multicentre, open, dose-finding study of a carboplatin-docetaxel (C-D) combination as first-line chemotherapy in FIGO stage Ic-IV epithelial ovarian cancer. C-D was given 3-weekly for 6 planned cycles, with a 3-day prophylactic dexamethasone regimen (8 mg b.i.d.). 139 eligible patients (Pts) (median age 56 years, range 28-85) were given a total of 750 cycles of chemotherapy in 5 cohorts: Co1, 32 pts, 169 cycles (C at AUC 5 + D 60 mg/m(2)); Co2, 22 pts, 122 cycles (5 + 75), Co3, 29 pts, 156 cycles (6 + 75), Co4, 27 pts, 146 cycles (7 + 75), Co5, 30 pts, 157 cycles (6 + 85). 110 patients (79%) completed 6 cycles; 17 (12%) stopped due to toxicity. 104 patients (75%) had CTC grade IV neutropenia, and 5 patients (4%) had this associated with fever. There were 2 probable treatment-related deaths. Only 8 patients (6%) experienced grade II-III neurotoxicity (all sensory; no motor > grade I). The maximum tolerated dose was reached in cohorts 4 and 5, and the dose limiting toxicities were myelosuppression and diarrhoea. The overall response rate for the study was 66% (49/74); CA125 response was 75% (70/93). Median progression-free survival was 16.6 months (95% CI 13.3-19.1). Recommended doses are carboplatin AUC 5 (via(51)Cr EDTA) or AUC 6 (if calculated) plus docetaxel 75 mg/m(2). A randomized trial comparing this regimen with carboplatin-paclitaxel has just completed recruitment.

Bone density of women who have recovered from anorexia nervosa

OBJECTIVE

To examine bone density in 19 women who had previously experienced classical anorexia nervosa from which they had been fully recovered for a mean of 21 years (current characteristics: median age 40.2 years; Eating Attitudes Test [EAT] score 2; body mass index [BMI] 21.1; average 1.8 offspring).

METHOD

Probands were compared, blindly, in respect of bone density, with 13 control subjects matched for age and sex and with no history of eating disorders. Dual energy X-ray absorptiometry (DXA) was used to evaluate the bone mineral density (BMD) of the lumbar spine and the head of the femur.

RESULTS

Femur BMD was still significantly less among ex-anorectic sufferers. Two subjects had experienced pathological fractures while anorectic, both having been strenuous exercisers. None appeared to have suffered post illness fractures. BMD at follow-up did not relate to the severity or chronicity of previous anorexia nervosa.

DISCUSSION

Full clinical recovery from anorexia nervosa does not quite confer full establishment of normal bone density. However, pathological fractures are not a feature thereafter, within middle life.

For four sixes

This article reviews the literature on orthodontic treatment involving extraction of first molars and highlights many of the clinical considerations when treating such cases. Case reports illustrate the potential problems and indicate some solutions.

Isolation, characterization and expression of a GRA2 homologue from Neospora caninum

A cDNA library derived from mRNA of tachyzoites of Neospora caninum (NC-Liverpool strain) was screened with antisera from a cow naturally infected with N. caninum. The DNA sequence of 1 recombinant isolated predicted a significant protein sequence homology of the gene product to the 28 kDa (GRA2) antigen of Toxoplasma gondii. Studies on the N. caninum gene coding for this antigen demonstrated the presence of a single intron flanked by 2 exons; the gene was also highly expressed in culture-derived tachyzoites. The antigen was expressed in Escherichia coli; when injected into mice it stimulated the production of antibodies which detected a 29 kDa antigen of N. caninum. Secondary structure predictions made for the N. caninum protein showed support for several amphipathic helices separated by loops and turns. The available evidence indicates maintenance of protein secondary structure, and not DNA or amino acid sequence, has occurred during the evolution of GRA2 proteins in N. caninum and T. gondii.

Progress in the serodiagnosis of Neospora caninum infections of cattle

Neospora caninum is an apicomplexan protozoan that has become the focus of significant research attention worldwide. This organism infects a range of host species, including dogs, from which it was originally reported in 1984, but it is most important as a major cause of bovine abortion. As a result of the global importance of N. caninum, researchers have developed a number of serological tests to investigate the epidemiology of infection and disease. In this article, Robert Atkinson, Peter Harper, Michael Reichel and John Ellis consider progress made in the serodiagnosis of N. caninum.

Contributions of Fas-Fas ligand interactions to the pathogenesis of mouse hepatitis virus in the central nervous system

The pathogenesis of the neurotropic strain of mouse hepatitis virus in Fas-deficient mice suggested that Fas-mediated cytotoxicity may be required during viral clearance after the loss of perforin-mediated cytotoxicity. The absence of both Fas- and perforin-mediated cytolysis resulted in an uncontrolled infection, suggesting a redundancy of cytolytic pathways to control virus replication.