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Match-Fixing Causing Harm to Athletes on a COVID-19-Influenced Gambling Market: A Call for Research During the Pandemic and Beyond. Front Psychol 2021; 12:712300. [PMID: 34621216 PMCID: PMC8490709 DOI: 10.3389/fpsyg.2021.712300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 08/20/2021] [Indexed: 11/13/2022] Open
Abstract
Match-fixing, although not a new problem, has received growing attention during the COVID-19 pandemic, which has been reported in the media to have increased the risk of match-fixing events. Gambling is a well-documented addictive behavior, and gambling-related fraud, match-fixing, is a challenge to the world of sports. Most research on match-fixing has a judicial or institutional perspective, and few studies focus on its individual consequences. Nevertheless, athletes may be at particular risk of mental health consequences from the exposure to or involvement in match-fixing. The COVID-19 crisis puts a spotlight on match-fixing, as the world of competitive sports shut down or changed substantially due to pandemic-related restrictions. We call for research addressing individual mental health and psycho-social correlates of match-fixing, and their integration into research addressing problem gambling, related to the pandemic and beyond.
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Biocatalysis in the Recycling Landscape for Synthetic Polymers and Plastics towards Circular Textiles. CHEMSUSCHEM 2021; 14:4028-4040. [PMID: 33497036 PMCID: PMC8518944 DOI: 10.1002/cssc.202002666] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/26/2021] [Indexed: 05/05/2023]
Abstract
Although recovery of fibers from used textiles with retained material quality is desired, separation of individual components from polymer blends used in today's complex textile materials is currently not available at viable scale. Biotechnology could provide a solution to this pressing problem by enabling selective depolymerization of recyclable fibers of natural and synthetic origin, to isolate constituents or even recover monomers. We compiled experimental data for biocatalytic polymer degradation with a focus on synthetic polymers with hydrolysable links and calculated conversion rates to explore this path The analysis emphasizes that we urgently need major research efforts: beyond cellulose-based fibers, biotechnological-assisted depolymerization of plastics so far only works for polyethylene terephthalate, with degradation of a few other relevant synthetic polymer chains being reported. In contrast, by analyzing market data and emerging trends for synthetic fibers in the textile industry, in combination with numbers from used garment collection and sorting plants, it was shown that the use of difficult-to-recycle blended materials is rapidly growing. If the lack of recycling technology and production trend for fiber blends remains, a volume of more than 3400 Mt of waste will have been accumulated by 2030. This work highlights the urgent need to transform the textile industry from a biocatalytic perspective.
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Reinforced versus standard stapler transection on postoperative pancreatic fistula in distal pancreatectomy: multicentre randomized clinical trial. Br J Surg 2021; 108:265-270. [PMID: 33793753 DOI: 10.1093/bjs/znaa113] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/11/2020] [Accepted: 11/06/2020] [Indexed: 01/01/2023]
Abstract
BACKGROUND Postoperative pancreatic fistula is the leading cause of morbidity after distal pancreatectomy. Strategies investigated to reduce the incidence have been disappointing. Recent data showed a reduction in postoperative pancreatic fistula with the use of synthetic mesh reinforcement of the staple line. METHODS An RCT was conducted between May 2014 and February 2016 at four tertiary referral centres in Sweden. Patients scheduled for distal pancreatectomy were eligible. Enrolled patients were randomized during surgery to stapler transection with biological reinforcement or standard stapler transection. Patients were blinded to the allocation. The primary endpoint was the development of any postoperative pancreatic fistula. Secondary endpoints included morbidity, mortality, and duration of hospital stay. RESULTS Some 107 patients were randomized and 106 included in an intention-to-treat analysis (56 in reinforced stapling group, 50 in standard stapling group). No difference was demonstrated in terms of clinically relevant fistulas (grade B and C): 6 of 56 (11 per cent) with reinforced stapling versus 8 of 50 (16 per cent) with standard stapling (P = 0.332). There was no difference between groups in overall postoperative complications: 45 (80 per cent) and 39 (78 per cent) in reinforced and standard stapling groups respectively (P = 0.765). Duration of hospital stay was comparable: median 8 (range 2-35) and 9 (2-114) days respectively (P = 0.541). CONCLUSION Biodegradable stapler reinforcement at the transection line of the pancreas did not reduce postoperative pancreatic fistula compared with regular stapler transection in distal pancreatectomy. Registration number: NCT02149446 (http://www.clinicaltrials.gov).
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Routine versus selective intraoperative cholangiography during cholecystectomy: systematic review, meta-analysis and health economic model analysis of iatrogenic bile duct injury. BJS Open 2020; 5:6056685. [PMID: 33688957 PMCID: PMC7944855 DOI: 10.1093/bjsopen/zraa032] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 09/26/2020] [Accepted: 09/28/2020] [Indexed: 01/07/2023] Open
Abstract
Background Bile duct injury (BDI) is a severe complication following cholecystectomy. Early recognition and treatment of BDI has been shown to reduce costs and improve patients’ quality of life. The aim of this study was to assess the effect and cost-effectiveness of routine versus selective intraoperative cholangiography (IOC) in cholecystectomy. Methods A systematic review and meta-analysis, combined with a health economic model analysis in the Swedish setting, was performed. Costs per quality-adjusted life-year (QALY) for routine versus selective IOC during cholecystectomy for different scenarios were calculated. Results In this meta-analysis, eight studies with more than 2 million patients subjected to cholecystectomy and 9000 BDIs were included. The rate of BDI was estimated to 0.36 per cent when IOC was performed routinely, compared with to 0.53 per cent when used selectively, indicating an increased risk for BDI of 43 per cent when IOC was used selectively (odds ratio 1.43, 95 per cent c.i. 1.22 to 1.67). The model analysis estimated that seven injuries were avoided annually by routine IOC in Sweden, a population of 10 million. Over a 10-year period, 33 QALYs would be gained at an approximate net cost of €808 000 , at a cost per QALY of about €24 900. Conclusion Routine IOC during cholecystectomy reduces the risk of BDI compared with the selective strategy and is a potentially cost-effective intervention.
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Release of Side-Chain Fluorinated Polymer-Containing Microplastic Fibers from Functional Textiles During Washing and First Estimates of Perfluoroalkyl Acid Emissions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:14329-14338. [PMID: 31697071 DOI: 10.1021/acs.est.9b04165] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The quantity and composition of fibers released from functional textiles during accelerated washing were investigated using the GyroWash method. Two fabrics [polyamide (PA) and polyester/cotton (PES/CO)] were selected and coated with perfluorohexane-based side-chain fluorinated polymers. Fibers released during washing ranged from ∼10 to 500 μ with a similar distribution for the two textile types. The PA-based fabric released considerably more fibers >20 μm in length compared to the PES/CO-based fabric (>1000/GyroWash for PA vs ∼200/GyroWash fibers for PES/CO). After one GyroWash (2-15 domestic washes), fibers that contained approximately 240 and 1300 μg total fluorine per square meter (μg F/m2) were released from the PA and PES/CO fabrics, respectively. Current understanding of the fate of microplastic fibers suggests that a large fraction of these fibers reach the environment either in effluent wastewater or sewage sludge applied to land. In the environment, the fluorinated side chains will be slowly cleaved from the backbone of the side-chain fluorinated polymers coated on the fibers and then transformed into short-chain perfluoroalkyl acids. On the European scale, emissions of up to ∼0.7 t of fluorotelomer alcohol (6:2 FTOH) per year were estimated for outdoor rain jackets treated with fluorotelomer-based side-chain fluorinated polymers.
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Identification and recovery of rare-earth permanent magnets from waste electrical and electronic equipment. WASTE MANAGEMENT (NEW YORK, N.Y.) 2017; 68:482-489. [PMID: 28751173 DOI: 10.1016/j.wasman.2017.07.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 05/19/2017] [Accepted: 07/17/2017] [Indexed: 06/07/2023]
Abstract
Nd-Fe-B permanent magnets are a strategic material for a number of emerging technologies. They are a key component in the most energy efficient electric motors and generators, thus, they are vital for energy technologies, industrial applications and automation, and future forms of mobility. Rare earth elements (REEs) such as neodymium, dysprosium and praseodymium are also found in waste electrical and electronic equipment (WEEE) in volumes that grow with the technological evolution, and are marked as critical elements by the European Commission due to their high economic importance combined with significant supply risks. Recycling could be a good approach to compensate for the lack of rare earths (REs) on the market. However, less than 1% of REs are currently being recycled, mainly because of non-existing collection logistics, lack of information about the quantity of RE materials available for recycling and recycling-unfriendly product designs. To improve these lack of information, different waste streams of electrical and electronic equipment from an industrial recycling plant were analyzed in order to localize, identify and collect RE permanent magnets of the Nd-Fe-B type. This particular type of magnets were mainly found in hard disk drives (HDDs) from laptops and desktop computers, as well as in loudspeakers from compact products such as flat screen TVs, PC screens, and laptops. Since HDDs have been investigated thoroughly by many authors, this study focusses on other potential Nd-Fe-B resources in electronic waste. The study includes a systematic survey of the chemical composition of the Nd-Fe-B magnets found in the selected waste streams, which illustrates the evolution of the Nd-Fe-B alloys over the years. The study also provides an overview over the types of magnets integrated in different waste electric and electronic equipment.
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SIMULATE-3 K coupled code applications. KERNTECHNIK 2017. [DOI: 10.3139/124.110801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
This paper describes the coupled code system TRACE/SIMULATE-3 K/VIPRE and the application of this code system to the OECD PWR Main Steam Line Break. A short description is given for the application of the coupled system to analyze DNBR and the flexibility the system creates for the user. This includes the possibility to compare and evaluate the result with the TRACE/SIMULATE-3K (S3K) coupled code, the S3K standalone code (core calculation) as well as performing single-channel calculations with S3K and VIPRE. This is the typical separate-effect-analyses required for advanced calculations in order to develop methodologies to be used for safety analyses in general. The models and methods of the code systems are presented. The outline represents the analysis approach starting with the coupled code system, reactor and core model calculation (TRACE/S3K). This is followed by a more detailed core evaluation (S3K standalone) and finally a very detailed thermal-hydraulic investigation of the hot pin condition (VIPRE).
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Abstract
Abstract
This paper describes the coupled code system S3K-RELAP5 and the application of the code system to BWR transients without scram. In addition short descriptions are given for application of the coupled system to fast transients and rod drop accidents. The models and methods of the code system are presented. Validation results are shown for a recorded transient event in the Forsmark 3 reactor. It is concluded that S3K-RELAP5 adequately captures the complicated interaction between physical processes in the reactor as well as the essential reactor protection and control systems, which qualifies it for applications to fast and slow transients, with or without scram, and Reactivity Initiated Accidents (RIA).
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EP-1081: Low rate of lymphedema after pelvic lymphadenectomy followed by pelvic irradiation of node positive prostate cancer. Radiother Oncol 2013. [DOI: 10.1016/s0167-8140(15)33387-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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A multiplexed point-of-care assay for C-reactive protein and N-terminal pro-brain natriuretic peptide. Anal Biochem 2011; 409:7-13. [DOI: 10.1016/j.ab.2010.09.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 09/17/2010] [Accepted: 09/22/2010] [Indexed: 11/28/2022]
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Abstract
The prognosis for patients suffering from cardiovascular and many other diseases can be substantially improved if diagnosed at an early stage. High performance diagnostic testing using disposable microfluidic chips can provide a platform for realizing this vision. Amic AB (Uppsala, Sweden) has developed a new microfluidic test chip for sandwich immunoassays fabricated by injection molding of the cycloolefin-copolymer Zeonor. A highly ordered array of micropillars within the fluidic chip distributes the sample solution by capillary action. Since wetting of the pillar array surface is the only driving force for liquid distribution precise control of the surface chemistry is crucial. In this work we demonstrate a novel protocol for surface hydrophilization and antibody immobilization on cycloolefin-copolymer test chips, based on direct silanisation of the thermoplastic substrate. Dextran is subsequently covalently coupled to amino groups, thus providing a coating with a low contact angle suitable for antibody immobilization. The contact angle of dextran coated chips is stable for at least two months, which enables production of large batches that can be stored for extended periods of time. We demonstrate the utility of the presented platform and surface chemistry in a C-reactive protein assay with a detection limit of 2.6 ng ml(-1), a dynamic range of 10(2) and a coefficient of variance of 15%.
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Asymmetric catalysis in a micro reactor—Ce, Yb and Lu catalysed enantioselective addition of trimethylsilyl cyanide to benzaldehyde. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.08.080] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Polymer-Supported Pyridine−Bis(oxazoline). Application to Ytterbium-Catalyzed Silylcyanation of Benzaldehyde. Org Lett 2003; 5:3663-5. [PMID: 14507199 DOI: 10.1021/ol0353363] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] Terminal acetylenes containing hydroxy and carboxylic acid groups were subjected to Sonogashira coupling with 4-bromo-2,6-bis[(R)-4-phenyloxazolin-2-yl]pyridine and the resulting pybox derivatives were immobilized on Tentagel resins. Ytterbium(III) chloride complexes of the polymeric ligands catalyzed the addition of trimethylsilyl cyanide to benzaldehyde with 80-81% ee. The ligands were reused more than 30 times without any loss in selectivity or activity, and the metal complexes could be recovered and reused at least four times, although with slightly decreasing activity.
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Abstract
Metal complexes of chiral oxazoline derivatives immobilized on soluble as well as insoluble supports serve as versatile asymmetric catalysts in a variety of applications. In a few cases recovery and reuse of the chiral ligands have been achieved.
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Abstract
A novel technique enabling selective bead trapping in microfluidic devices without the use of physical barriers is presented in this paper. It is a fast, convenient and simple method, involving microcontact printing and self-assembly, that can be applied to silicon, quartz or plastic substrates. In the first step, channels are etched in the substrate. The surface chemistry of the internal walls of the channels is then modified by microcontact printing. The chip is submerged in a bead slurry where beads self-assemble based on surface chemistry and immobilize on the internal walls of the channels. Silicon channels (100 microm wide and 50 microm deep) have been covered with monolayers of streptavidin-, amino- and hydroxy-functionalized microspheres and resulted in good surface coverage of beads on the channel walls. A high-resolution pattern of lines of self-assembled streptavidin beads, as narrow as 5 microm, has also been generated on the bottom of a 500 microm wide and 50 microm deep channel. Flow tests were performed in sealed channels with the different immobilized beads to confirm that the immobilized beads could withstand the forces generated by water flowing in the channels. The presented results indicate that single beads can be precisely positioned within microfluidic devices based on self-assembly which is useful as screening and analysis tools within the field of biochemistry and organic chemistry.
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Arsenic trioxide inhibits neuroblastoma growth in vivo and promotes apoptotic cell death in vitro. Biochem Biophys Res Commun 2000; 277:179-85. [PMID: 11027660 DOI: 10.1006/bbrc.2000.3651] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent clinical studies have shown that inorganic arsenic trioxide (As(2)O(3)) at low concentrations induces complete remission with minimal toxicity in patients with refractory acute promyelocytic leukemia (APL). Preclinical studies suggest that As(2)O(3) induces apoptosis and possibly differentiation in APL cells. Like APL cells, neuroblastoma (NB) cells are thought to be arrested at an early stage of differentiation, and cells of highly malignant tumors fail to undergo spontaneous maturation. Both APL and NB cells can respond with differentiation to retinoic acid (RA) treatment in vitro and probably also in vivo. For that reason we investigated the effect of As(2)O(3) alone and in combination with RA on NB cell lines. In vitro, the number of viable NB cells was reduced at As(2)O(3) concentrations around 1 microM after 72 h exposure. The IC50 in six different cell lines treated for 3 days was in the 1.5 to 5 microM concentration interval, the most sensitive being SK-N-BE(2) cells derived from a chemotherapy resistant tumor. The combined treatment with RA (1 and 3 microM) showed no consistent additional effect with regard to induced cell death. The effect of As(2)O(3) on NB cell number involved As(2)O(3)-induced apoptotic pathways (decreased expression of Bcl-2 and stimulation of caspase-3 activity) with no clear evidence of induced differentiation. The in vivo effect of As(2)O(3) on NB growth was also investigated in nude mice bearing tumors of xenografted NB cells. Although tumor growth was reduced by As(2)O(3) treatment, complete remission was not achieved at the concentrations tested. We suggest that As(2)O(3), in combination with existing treatment modalities, might be a treatment approach for high risk NB patients.
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Is the esophageal squamous epithelial barrier function impaired in patients with gastroesophageal reflux disease? Scand J Gastroenterol 1999; 34:454-8. [PMID: 10423058 DOI: 10.1080/003655299750026155] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND A disturbed epithelial barrier function has been promoted as one factor in the pathogenesis of gastroesophageal reflux disease (GERD). We therefore studied the effect of acid perfusion on the transmural potential difference (PD) of the distal esophagus in relation to onset of reflux symptoms. METHODS PD was assessed during perfusion with saline and with 0.1 M HCl in healthy controls (n = 17) and in GERD patients without (n = 15) or with esophagitis (n = 6) and in remission after a fundoplication (n = 10). Heartburn and other upper GI symptoms were recorded concomitantly. Endoscopy-negative patients were studied before and after omeprazole treatment. RESULTS HCl perfusion induced more lumennegative peak PD values in patients with active GERD, regardless of the presence or absence of esophagitis, than in healthy controls. After successful therapy, the PD response to acid perfusion equalled that of healthy subjects. Acid perfusion was associated with the onset of heartburn in most patients with active GERD but in none of the healthy subjects, and less frequently after medical and surgical therapy. CONCLUSIONS The epithelial permeability to hydrogen ions differs between healthy subjects and patients with active GERD. Effective treatment, such as omeprazole or fundoplication, might improve the barrier function.
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Identification of regions of HIV-1 p24 reactive with sera which give "indeterminate" results in electrophoretic immunoblots with the help of long synthetic peptides. AIDS Res Hum Retroviruses 1990; 6:1363-72. [PMID: 2127683 DOI: 10.1089/aid.1990.6.1363] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We analyzed nine sera from persons unlikely to be HIV infected which had an IgG reactivity directed against HIV-1 p24, and in two cases also to its precursor p55, but to no other HIV proteins, nor to proteins of the H9 host cell, in electrophoretic immunoblots (EIB). These sera are also referred to as having an indeterminate HIV EIB pattern or as HIV antibody false positive sera. Seven of nine sera reacted with longer (61-77 amino acids) and none with shorter (17-25 amino acids) p24-derived peptides in enzyme immunoassays (EIAs). This is compatible with a conformational (discontinuous) nature of the epitopes involved in many false positive HIV-1 p24 antibody reactions. Four sera reacted with an N-terminal, one with an internal, and two with a C-terminal fragment. Each of the seven sera thus only reacted with one of the long p24 peptides. The specificity and singularity of the reaction was further demonstrated by competition and/or absorption experiments with synthetic peptides. In contrast, 18 of 20 confirmed HIV-1+ sera with p24 reactivity in EIB reacted with at least one and often several of the longer peptides, most frequently the C-terminal one. Thus, the distribution of peptide reactivity of true HIV-1 antibody-positive sera was different from that of the falsely reactive sera. According to two of several explanations, these antibodies may have arisen because of (1) molecular mimicry by chance or by functional selection, (2) immunization by activation, noninfectious exposure, or infection involving non-HIV endogenous or exogenous retroviral antigens. The latter gains some support from our finding of antibody reactions with capsid proteins of the simian viruses, simian sarcoma-associated virus (SSAV), and Mason-Pfizer monkey retrovirus in some of the p24 +/- p55 reactive sera.
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Effects of histamine H2-receptor blockade on the cardiovascular reflex response to lower-body negative pressure in man. ACTA PHYSIOLOGICA SCANDINAVICA 1990; 139:161-72. [PMID: 1972605 DOI: 10.1111/j.1748-1716.1990.tb08909.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The role of histamine H2-receptors in cardiovascular control is unknown. In seven healthy volunteers, we studied how histamine H2-receptor blockade affected the reflex response to hypovolaemia induced by lower-body negative pressure (LBNP). In placebo-treated individuals, LBNP down to -40 mmHg did not change systolic pressure but increased diastolic pressure, heart rate, forearm vascular resistance, plasma noradrenaline concentration and plasma renin activity. After pretreatment with ranitidine, a specific histamine H2-receptor antagonist, the diastolic pressure rise no longer sufficed to maintain a constant systolic pressure during LBNP. Ranitidine pretreatment also attenuated the heart rate response and the rise in plasma renin activity induced by LBNP, but did not significantly change the reflex forearm vasoconstriction or the forearm plasma noradrenaline response. The results suggest that histamine H2-receptor blockade attenuates the reflex vasoconstrictor response to lower-body negative pressure. The mechanism behind this effect remains unknown, but the data do not support the idea that the effect is exerted in the skeletal muscle vascular bed.
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Abstract
A method which is simple, reliable, and rapid to use in clinical routine for basic dose calculation in total body irradiation (TBI) has been tested with 8 MV x-rays. The dosimetry follows, as far as possible, national and international recommendations for conventional radiotherapy. The dose rate at different locations and depths is calculated from the absorbed dose rate at dose maximum for a phantom size of 30 x 30 x 30 cm in the TBI field (Dc), an inverse square law factor (SAD2/SPD2), the tissue-maximum ratio (TMR), an equivalent phantom and patient size correction factor (A), a factor for lack of back-scattering material (B), an off-axis output correction factor (O), and a factor that corrects for off-axis variations in effective photon beam energy and for oblique beam penetration of the patient (R). The collimator opening is constant for all patient sizes. It is shown that TMR, A, B and R can be measured in conventional geometry in ordinary phantoms but at an extended distance, while Dc, O and SAD2/SPD2 must be measured in TBI geometry. Tests in Humanoid phantoms showed an agreement in measured and planned AP/2 doses of 2% or better. If the calculation method is used for lower photon energies or in other TBI geometries it may be necessary to correct for the elliptical shape of the patient and for back-scattered radiation from the walls or floor.
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Studies of cholera toxin-induced changes of alkaline secretion and transepithelial potential difference in the rat intestine in vivo. ACTA PHYSIOLOGICA SCANDINAVICA 1990; 138:75-84. [PMID: 2309571 DOI: 10.1111/j.1748-1716.1990.tb08814.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A pH-stat technique was used to investigate the effects of cholera toxin (CT) on alkaline secretion from denervated intestines (jejunum, ileum, colon) in anaesthetized rats. Transepithelial potential difference (PD) was also followed in some experiments. CT, given intraluminally, caused a marked increase in jejunal alkaline secretion, whereas only a small effect was observed in the ileum and no apparent effect was noted in the proximal colon. The pronounced increase in jejunal alkaline secretion was found to be inhibited by 10-25% by hexamethonium (10 mg kg-1 body wt i.v.) and similarly by serosal application of lidocaine, whereas atropine (0.25 mg kg-1 body wt i.v.) had no effect. Thus the cholera toxin-induced alkaline secretion in the jejunum is attributed mainly to a non-nervous mechanism. The small effect of CT on ileal alkaline secretion observed in this study contrasts with the high ileal bicarbonate concentration reported in cholera by authors who estimated the concentration from the total carbon dioxide/bicarbonate contents. This discrepancy may be explained by a CT-evoked increased transport of the coupled Na+/H+ and Cl-/HCO3- exchangers, which cannot be measured with the pH-stat technique used in this study.
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[Improvement in the resolution of a light optical lens by means of a zone correction plate]. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 1966; 53:609. [PMID: 5990834 DOI: 10.1007/bf00632270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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