Fingerprinting of chlorinated paraffins and their transformation products in plastic consumer products.

Chlorinated paraffins (CPs) can be classified according to their length as short-chain (SC, C10-C13), medium-chain (MC, C14-C17) and long-chain (LC, C ≥ 18) CPs. Technical CP-mixtures can contain a wide range of carbon- (C-, nC = 10-30) and chlorine- (Cl-, nCl = 3-19) homologues. CPs are high-production volume chemicals (>106 t/y). They are used as flame-retardants, plasticizers and coolant fluids. Due to the persistence, bioaccumulation, long-range environmental transport potential and adverse effects, SCCPs are regulated as persistent organic pollutants (POPs) by the Stockholm Convention. Transformation of CPs can lead to the formation of unsaturated compounds such as chlorinated mono- (CO), di- (CdiO) and tri-olefins (CtriO). Such transformation reactions can occur at different stages of CP manipulation providing characteristic C-/Cl-homologue distributions. All this results in unique patterns that collectively create a fingerprint, which can be distinguished from CP-containing samples. Therefore, CP-fingerprinting can develop into a promising tool for future source apportionment studies and with it, the reduction of environmental burden of CPs and hazards to humans. Herein, CP-containing plastics were studied to establish fingerprints and develop this method. We analyzed four household items by reverse-phase liquid-chromatography coupled with a mass spectrometer with an atmospheric pressure chemical ionization source and an Orbitrap mass analyzer (RP-LC-APCI-Orbitrap-MS) operated at a resolution of 120000 (FWHM at m/z 200). MS-data of different CP-, CO-, CdiO- and CtriO-homologues were efficiently processed with an R-based automatic mass spectra evaluation routine (RASER). From the 16720 ions searched for, up to 4300 ions per sample were assigned to 340 C-/Cl-homologues of CPs and their transformation products. Specific fingerprints were deduced from the C-/Cl-homologues distributions, the carbon- (nC) and chlorine- (nCl) numbers and saturation degree. These fingerprints were compared with the ones obtained by a GC-ECNI-Orbitrap-MS method.

WWTP design in warm climates - guideline comparison and parameter adaptation for a full-scale activated sludge plant using mass balancing.

The ATV-A-131 guideline and the design approach published in 'Wastewater Engineering, Treatment and Reuse (WE)' are widely used for the design of activated sludge plants. They are both based on simplified steady-state assumptions tailored to the boundary conditions of temperate climates. Using design guidelines beyond the designated temperature range may lead to inappropriate results. The objectives of this paper are (1) to summarise temperature relevant differences between ATV-A-131 and WE; (2) to show the related design components; and (3) to demonstrate a procedure for design parameter adaptation for a full-scale activated sludge plant located in a warm climate region. To gain steady-state data required for wastewater treatment plant (WWTP) design according to ATV-A-131 and WE, full-scale plant data were acquired for a period of 6 months as a basis for analyses and adaptation. Mass balances were calculated for the verification of the measurements and for analysing excess sludge production. The two approaches showed relevant temperature related differences. WE default application resulted in lower deviation in the mass balance results for excess sludge production. However, with the adaptation of the heterotrophic decay rates for both approaches and the inert organic and mineral solids fraction additionally for ATV-A-131, a good fit to the observed excess sludge production could be achieved.

Ischemic stroke injury is reduced in mice lacking a functional NADPH oxidase.

BACKGROUND AND PURPOSE: Free radicals account for a significant proportion of the brain damage that occurs during ischemic stroke. Using mutant mice (X-CGD) with a dysfunctional phagocytic NADPH oxidase, we investigated the role of this superoxide-generating enzyme as a mediator of the reperfusion injury in a mouse model of middle cerebral artery occlusion. METHODS: Transient (2 hour) middle cerebral artery occlusion was performed in X-CGD or wild-type litter mates (8- to 10-week-old). After 22 hours of reperfusion, brains were harvested and infarct volume delineated using 2,3,5-triphenyl-tetrazolium chloride. To elucidate the origin of the damaging NADPH oxidase, transient ischemia was also performed in X-CGD or wild-type mice transplanted with wild-type C57 B1/6J or X-CGD bone marrow, respectively. RESULTS: The infarct volume induced by transient ischemia was significantly less in X-CGD mice (29.1 +/- 5.6 mm3; n = 13) than wild-type littermates (54.0 +/- 10.6 mm3; n = 10; P < .05). The elimination of a functional NADPH oxidase from either the circulation or the central nervous system, by performing the appropriate bone marrow transplant experiments, did not reduce the infarct size induced by transient ischemia. This suggests that in order to confer protection against transient ischemia and reperfusion, a putative neuronal and circulating NADPH oxidase need to be inactivated. CONCLUSIONS: Brain injury was reduced in mice lacking a functional NADPH oxidase in both the central nervous system and peripheral leukocytes, suggesting a pivotal role for the NADPH oxidase in the pathogenesis of ischemia-reperfusion injury in the brain.

Vascular endothelial growth factor augments muscle blood flow and function in a rabbit model of chronic hindlimb ischemia.

Animal studies have shown that angiogenic factors can increase vascularity and improve blood pressure (BP) in an ischemic limb. Whether changes in these parameters are indicators of significant improvement in muscle function has not been demonstrated. In a rabbit model of hind limb ischemia, we measured blood flow in the extensor digitorum longus muscle (EDL) both at rest and during electrical stimulation. Ablation of the femoral artery caused significant reductions in resting and stimulated EDL blood flow. The chronic reduction in perfusion caused impairment of muscle function (p < 0.01). At 28 days after a single administration of vascular endothelial growth factor (VEGF), stimulated muscle blood flow (3 mg/kg intravenously, i.v.) and muscle function [1 mg intrarterially (i.a.) or 3 mg/kg i.v.] were significantly improved as compared with that of vehicle-treated controls. Simultaneous measurement of the hemodynamic responses in the contralateral limb and in the kidneys confirmed that the effects of VEGF were confined to the ischemic limb. The data agree with findings that angiogenic factors increase perfusion through angiogenesis. We hypothesized that neovascularization allows work-associated muscle hyperemia, resulting in a significant improvement in muscle function. Similar clinical improvements in muscle function would signify a substantial advance in the treatment of peripheral vascular disease.

Support of renal blood flow after ischaemic-reperfusion injury by endogenous formation of nitric oxide and of cyclo-oxygenase vasodilator metabolites.

1. Ischaemia-reperfusion injury in the kidney is associated with a loss of autoregulation, an increase in renal vascular resistance (RVR), a decrease of renal blood flow (RBF) and ultimately acute renal failure. The aim of this study was to investigate the role of the release of endogenous nitric oxide (NO) in the recovery of RBF after ischaemic injury of the renal vascular bed. 2. Anaesthetized rats (thiopentone sodium; 120 mg kg-1, i.p.) were submitted to acute renal ischaemia followed by 2 or 6 h of reperfusion (I/R). Reperfusion was associated with a significant reduction in RBF, an increase in RVR, and an impairment of the vasodilator effect of acetylcholine (ACh). 3. NG-nitro-L-arginine methyl ester (L-NAME, 30 micrograms kg-1 min-1, i.v., n = 5) significantly prevented the recovery of RBF after I/R injury. Similarly, inhibition of prostanoid formation with indomethacin (5 mg kg-1, i.v., n = 4) significantly enhanced the rise in RVR associated with I/R injury. 4. Infusion of L-arginine (L-Arg; 1 or 3 mg kg-1 min-1, i.v., n = 5 and 4, respectively) or D-Arg (1 mg kg-1 min-1, i.v., n = 6), starting 30 min after occlusion, did not improve the recovery of RBF. Furthermore, infusion of L-Arg (20 mg kg-1 min-1 for 15 min; n = 4) had no effect on the I/R-induced impairment of the vasodilator responses to ACh. 5. To elucidate the relative importance of the constitutive and inducible NO synthase isoforms for the formation of NO after I/R, calcium-dependent (constitutive) and calcium-independent (inducible) NO synthase activities were measured in kidney homogenates obtained from ischaemic or non-ischaemic kidneys. A calcium-independent NO synthase activity was not detectable in kidney homogenates obtained from either sham-operated control rats or from animals subjected to I/R. Moreover, dexamethasone(3 mg kg-1, i.v., 60 min prior to I/R, n = 6), an inhibitor of the induction of NO synthase,had no effect on either RBF or RVR in rats subjected to I/R. In contrast to I/R, lipopolysaccaride(LPS, endotoxin; 5 mg kg-1, i.p., n = 3) caused a significant induction of a calcium-independent NO synthase activity in the kidney.6. These results confirm the importance of the release of vasodilator cyclo-oxygenase metabolites in the compromised renal circulation and indicate that the formation of NO derived from the constitutive, but not the inducible NO synthase, is also important for the maintenance of RBF after I/R injury of the renal vascular bed.

NG-hydroxy-L-arginine prevents the haemodynamic effects of nitric oxide synthesis inhibition in the anaesthetized rat.

1. We have investigated the effects of L-hydroxy-L-arginine (L-HOArg), an intermediate in the biosynthesis of nitric oxide (NO) from L-arginine (L-Arg), on the haemodynamic effects (systemic blood pressure and renal blood flow) of the NO synthesis inhibitor NG-nitro-L-arginine methyl ester (L-NAME) in the anaesthetized rat. 2. L-Arg or L-HOArg (3 mg kg-1 min-1), but not D-arginine (D-Arg) or NG-hydroxy-D-arginine (D-HOArg), elicited a slight but significant increase in total renal blood flow (RBF) of 11 +/- 2% and 11 +/- 1%. Since mean arterial blood pressure (MAP) did not change this dose of L-Arg or L-HOArg resulted in a reduced renal vascular resistance (RVR) of the same magnitude. 3. Bolus injections of L-NAME, at 0.3 or 1 mg kg-1 i.v., produced a significant fall in RBF of 11 +/- 2% and 32 +/- 5% and an increase in MAP of 7 +/- 3 mmHg and 22 +/- 5 mmHg, respectively. Consequently, RVR was elevated by 21 +/- 5% and 52 +/- 10%. 4. L-Arg or L-HOArg (3 mg kg-1 min-1) reduced the L-NAME-induced (0.3 or 1 mg kg-1) falls in RBF and increases in RVR by more than 65%. Neither D-Arg nor D-HOArg (3 mg kg-1 min-1) had any significant effect on the changes in RBF or RVR induced by L-NAME. 5. L-Arg or L-HOArg (3 mg kg-' min-') attenuated the pressor effect of L-NAME (3 mg kg-') by 73% and 64%, respectively, while neither the D-isomer of arginine nor hydroxyarginine had any effect.6. These results demonstrate that L-HOArg antagonizes the haemodynamic effects of NO-biosynthesis inhibition in vivo, thus supporting the hypothesis that L-HOArg is an intermediate in the formation of NO from L-Arg.

Psychomotor testing and the ability to perform an anastomosis in junior surgical trainees.

Ten junior surgical trainees underwent objective testing of manual dexterity and visuospatial ability and were required to carry out five consecutive anastomoses on fresh porcine jejunum. Anastomoses were scored by a single observer and a cumulative error score (CES) derived for each procedure. In the first anastomosis there was little correlation between the psychomotor test results and the anastomosis scores. In subsequent trials there were significant negative correlations between aspects of manual dexterity and the CES. Over the five anastomoses there were significant negative correlations between improvement and manual dexterity, but there was a positive correlation between improvement and visuospatial ability (rs = 0.76, P < 0.005). Visuospatial skills are more important than pure motor ability in predicting the capacity to perform an anastomosis and tests of manual dexterity may be misleading in this context.

The involvement of endothelium-derived relaxing factor in the regulation of renal cortical blood flow in the rat.

1. In the present study the role of endogenous nitric oxide (NO) was investigated, in the regulation of renal cortical blood flow (RCBF) in vivo in anaesthetized rats under conditions in which prostacyclin involvement had been eliminated. 2. Infusions of the NO synthesis inhibitor NG-monomethyl-L-arginine (MeArg) at 1 or 3 mg kg-1 min-1, i.v., produced significant decreases in RCBF of 29 +/- 7% and 35 +/- 5%, respectively. These effects were reversed by co-infusion of a 3 fold excess of L-arginine (L-Arg). 3. Similarly, intravenous infusion of N omega-nitro-L-arginine methyl ester (NO2Arg) at 30 or 300 micrograms kg-1 min-1 attenuated RCBF by 21 +/- 4% or 53 +/- 4%, respectively, and these effects were reversed by L-Arg (3 or 10 mg kg-1 min-1, i.v.). Most importantly, a low dose of NO2Arg (30 micrograms kg-1 min-1, i.v.), while having no pressor effect, considerably reduced RCBF, indicating that basal release of NO is important for the maintenance of renal cortical blood flow. 4. MeArg (3 mg kg-1 min-1, i.v.) or NO2Arg (300 micrograms kg-1 min-1, i.v.) inhibited endothelium-dependent acetylcholine (ACh, 10 micrograms kg-1 min-1, i.v. for 3 min) increases in RCBF in an L-Arg reversible manner, but did not affect endothelium-independent (dopamine 10 micrograms kg-1 min-1, i.v., for 3 min) increases. Endothelin- 1 (1 nmol kg-1, i.v.), when given as a control for the vasoconstrictor effects of MeArg and NO2Arg, produced a slight inhibition of the ACh-induced increase in RCBF, but this effect was significantly weaker than that produced by MeArg or NO2Arg. 5. Our findings suggest that MeArg and NO2Arg inhibit basal and ACh-stimulated release of NO in the renal cortical vasculature. Thus, endogenous NO formation may play an important role in the local regulation of renal cortical blood flow.

Endothelium-derived relaxing factor participates in the increased blood flow in response to pentagastrin in the rat stomach mucosa.

The stimulation of gastric-acid secretion by pentagastrin, a synthetic analogue of the endogenous peptide gastrin, is associated with an increased blood flow to the stomach mucosa, commonly referred to as functional hyperaemia. There are at least two potent vasodilator substances, the local release of which from endothelial cells could contribute to this hyperaemia, endothelium-derived relaxing factor (EDRF) and prostacyclin. EDRF has been identified as nitric oxide, released enzymatically from the guanidino group of L-arginine. In the present studies, the involvement of prostacyclin in the pentagastrin-induced increase in stomach blood flow was eliminated by using the cyclo-oxygenase inhibitor indomethacin. Thus this work was designed to elucidate the participation of EDRF/NO in the pentagastrin-induced hyperaemia and not its relative importance to prostacyclin. The increase in blood flow to the gastric mucosa in response to pentagastrin was measured by laser Doppler flowmetry in situ. Inhibition of EDRF/NO biosynthesis with the L-arginine analogues NG-monomethyl-L-arginine (MeArg) or N omega-nitro-L-arginine (NO2Arg) significantly attenuated (by more than 80%) the increase in mucosal blood flow in response to pentagastrin. However, infusions of the natural substrate L-arginine reversed the inhibitor effect of MeArg on pentagastrin-induced increase in mucosal blood flow. Local intra-arterial injections of the endothelium-independent vasodilator glyceryl trinitrate produced a dose-related increase in blood flow to the rat stomach mucosa that was unaffected by infusion of MeArg. Thus, in the absence of prostacyclin, EDRF/NO participates in the pentagastrin-induced increase in blood flow to the rat stomach mucosa.

Regional vascular resistance and haemodynamics in the spontaneously hypertensive rat: the effects of bradykinin.

To identify those vascular beds that contribute to the elevated peripheral resistance (TPR) seen in spontaneously hypertensive rats (SHR) as compared to Wistar-Kyoto rats (WKY), the distribution of cardiac output, organ blood flow, and regional vascular resistance were measured using radiolabelled microspheres. WKY and SHR had similar heart rates, cardiac outputs, and cardiac stroke volumes, whereas SHR had significantly elevated TPR. This increased TPR was the cumulative effect of significant elevations in vascular resistance in the brain, testes, epididymides, gastrointestinal tract, pancreas/mesentery, skin, kidneys, and skeletal muscle. Only in the renal and skeletal muscle vasculature was this elevation in resistance associated with reduced blood flow. Haemodynamic responses to bradykinin [thought to act through a release of endothelium-derived relaxing factor (EDRF)] were similar in both WKY and SHR with the exception of the liver where no reduction of hepatic arterial resistance was seen in the SHR. We suggest that the increase in resistance in the renal and skeletal muscle vasculature is due to active vasoconstriction in these beds. This vasoconstriction diverts a significant proportion of the cardiac output through other vascular beds, especially the brain, liver, and coronary circulation. This will result in increased shear-stress and consequent damage to endothelial cells.

Interhemispheric transfer in schizophrenics, depressives, and normals with schizoid tendencies.

Although several studies suggest that schizophrenics suffer from an impairment in the interhemispheric transfer (IHT) of information, methodological weaknesses in these studies preclude clear interpretation of their results. This study addresses these criticisms in order to provide a clearer test of the IHT theory. Schizophrenics, depressives, normal controls, and normals with schizoid tendencies were assessed on five measures of IHT (verbal and nonverbal dichotic listening, intermanual transfer, bimanual block design, finger sequence repetition) and two measures of unilateral hemispheric processing (lateral eye movements, auditory thresholds). Results consistently failed to support an IHT deficit interpretation of schizophrenia. Schizoid normals had a significantly greater right-ear advantage on verbal dichotic listening than both psychiatric groups, a result suggesting enhanced left-hemisphere activation in schizoid normals. It is concluded that the IHT theory requires stronger empirical substantiation than has been obtained to date to warrant further consideration as a central theory of schizophrenia.

Peritoneal barrier to the spread of Semliki forest virus in mice.

The LD50 for encephalitis caused by Semliki forest virus in 6- to 8-week-old mice is 1 plaque-forming unit (PFU) in C3H/Ten strain of mice when injected intracerebrally, iv, or in the footpad; however, the LD50 by the ip route is 4 x 10(3) PFU. In the ICR strain of mice at the same age, the LD50 for the intracerebral route is 1 PFU, 10(3) PFU for the iv and footpad routes, and 4 x 10(3) PFU for the ip route. A number of in vivo and in vitro experiments were done to explain the relative resistance to Semliki forest virus injection by the ip route. The results suggest that the viruses are adsorbed to and enter adherent cells of the peritoneal cavity but do not replicate and release progeny virus. After inoculation with the virus, viral antigens could only be observed in methanol-treated cells as a halo by immunofluorescence at or just below the plasma membrane of only a small fraction (less than 0.5%) of peritoneal adherent cells. Naturally occurring interferon-alpha/beta (less than 1 unit/ml) was found to probably play a marginal role, if any, in the resistance.

The hemodynamic effects of endothelin-1 in the pithed rat.

The pressor effects of porcine (ET-1) and rat (ET-3) endothelins were studied in the pithed rat along with the actions of cyclo-oxygenase inhibitors upon these responses. Indomethacin (15 mumol/kg i.v.) when given prior to endothelin had no effect on the pressor responses to ET-1 or ET-3. However, when indomethacin or piroxicam was administered between two doses of ET-1 or ET-3, the second response was significantly potentiated. This potentiation was abolished when the adrenal glands were excluded from the circulation but partially restored when neuropeptide Y (NPY) (1 nmol/kg i.v.) was administered. Radiolabeled microspheres were used to measure regional blood flow and from these measurements, regional vascular resistance was calculated. From these data, it is evident that ET-1 caused a generalized increase in vascular resistance, and only in the large intestine and epididymal fat pad was this attenuated by indomethacin. In the gastric vasculature, the effects of ET-1 were potentiated by indomethacin. In the bronchial vasculature, ET-1 caused a reduction in vascular resistance possibly due to the bronchoconstrictor actions of ET-1 and the concomitant release of vasodilators such as histamine. When the fraction of the cardiac output received by each vascular bed is taken into account, the gastrointestinal tract, kidneys, and skeletal muscle account for most of the increase in total peripheral resistance induced by ET-1. Prostanoids have a role in the pressor response to ET-1 and ET-3 that is more complex than one of simple physiological antagonism or potentiation at the level of the vascular smooth muscle and possibly act as modulators of other regulatory factors such as NPY.

Pressor effects of circulating endothelin are limited by its removal in the pulmonary circulation and by the release of prostacyclin and endothelium-derived relaxing factor.

Endothelin releases prostacyclin and thromboxane A2 from guinea pig or rat isolated lungs and endothelium-derived relaxing factor in the perfused mesentery of the rat. Endothelin is also substantially removed by the pulmonary circulation of the rat in vitro and in vivo and by guinea pig lungs in vitro. In the rat, the effects of endothelin on the blood pressure vary from pressor (in pithed rats) to purely depressor in anesthetized rats where the resting blood pressure is high. It therefore has the characteristics of a local pressor hormone, rather than a circulating one.

The effects of endothelium-dependent vasodilators on cardiac output and their distribution in the anaesthetized rat: a comparison with sodium nitroprusside.

1. The effects of sodium nitroprusside, acetylcholine and bradykinin on cardiac output and its distribution were studied in the anaesthetized, vagotomised rat preparation by use of 113Sn-labelled microspheres. 2. All three vasodilators lowered peripheral arterial blood pressure, but only bradykinin significantly reduced total peripheral resistance without reducing cardiac output. Bradykinin caused tachycardia, but this was offset by a reduction in stroke volume. These effects of bradykinin were not altered by indomethacin (4 mg kg-1). Acetylcholine and sodium nitroprusside both caused significant (P less than 0.05) reductions in stroke volume and cardiac output. 3. Bradykinin reduced vascular resistance in the liver, stomach, small intestine, large intestine, pancreas/mesentery, epididimides, skeletal muscle and fat. These responses were not affected by indomethacin, whereas, the reduction in vascular resistance in the brain induced by bradykinin was abolished by indomethacin. 4. Acetylcholine caused a reduction in renal vascular resistance, where bradykinin had no effect. However, acetylcholine did not cause any haemodynamic changes in the bradykinin-sensitive intestinal vasculature. 5. Acetylcholine caused vasoconstriction in the coronary and epididymal vasculature. Bradykinin in the presence of indomethacin induced vasoconstriction in the skin. 6. In conclusion, the data show that, with the possible exception of the brain and the skin, the vasodilator actions of bradykinin can adequately be transduced (presumably by endothelium-derived relaxing factor, EDRF) in the absence of prostacyclin synthesis. Additionally, these results indicate that the vasculature of the stomach, pancreas/mesentery, epididimides and skeletal muscle are equally sensitive to both acetylcholine and bradykinin, whereas the kidneys showed selectivity towards acetylcholine and the intestines towards bradykinin. These results may indicate differential receptor populations.

Psychological intervention in civilian flying phobia. Evaluation and a three-year follow-up.

Thirty-eight people with a moderate to severe degree of aerophobia self-referred themselves to a course designed to help them travel by air. The course involved three long sessions based on giving information, graded exposure without avoidance, and group support with natural coping models. Measures of self-reported anxiety levels were taken at regular intervals. The results showed that being given information or undergoing a simulated flight had little effect on perceived anxiety. Prolonged exposure to flying had a marked effect on reducing anxiety and anticipated apprehension about future flying. At one-year and three-year follow-up, 40% and 60% of participants had flown commercially, although there was some minor restoration of anticipated anxiety associated with flying; 84% showed less anxiety about flying. Psychological intervention, in collaboration with airlines, may have marked benefits in reducing fear of flying.

Vasopressin and memory: improvement in normal short-term recall and reduction of alcohol-induced amnesia.

The vasopressin analogue 1-desamino-8-D-arginine vasopressin (DDAVP) has been shown in healthy male volunteers to cause significant improvement in short-term memory and to reduce alcohol-induced amnesia. There was no significant effect upon semantic retrieval or simple reaction time. It was concluded that vasopressin benefited the initial processes of consolidation and learning, while the reduction of the amnesic effects of alcohol may support the contentions of other authors that the peptide improves memory in states of mild amnesia.

Prolactin and stress: some endocrine correlates of pre-operative anxiety.

An attempt was made to correlate the serum concentration of PRL, GH and cortisol with anxiety experienced before elective surgery. A significant direct correlation was observed between cortisol and anxiety (P = 0.028), and between GH and anxiety (P = 0.001) although the latter correlation may have reflected the confounding effects of sex and age on GH levels. No correlation was observed between anxiety and PRL and we conclude that psychosocial stress cannot be invoked as an occasional cause of hyperprolactinaemia.