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1.
Schmerz ; 37(1): 29-37, 2023 Feb.
Artigo em Alemão | MEDLINE | ID: mdl-35384481

RESUMO

BACKGROUND: Relevant data for the prescription and therapeutic effects of medical cannabinoids (CAM) are still missing in everyday medicine especially for elderly and geriatric patients. AIM OF THE STUDY: Documentation of prescription (duration, age) of CAM (dronabinol, nabiximols, cannabinoid extracts) and co-medicated opioids in a doctor's office specializing in pain. METHODS: Analysis of the consumption of opioids (morphine equivalent) and CAM (THC equivalent) for age and gender. RESULTS: In all, 178 patients with chronic pain were treated for a period of 366 days (median; range 31-2590 days). Median age was 72 years (26-96 years); 115 were women (64.8%). Of these, 34 were younger than 65 years, 42 were 65-80 years and 40 were more than 80 years old. Of the 63 men, 29 were younger than 65 years, 24 were 65-80 years and 10 were older than 80 years. Indications for CAM were chronic pain and the limitations for opioids because of side effects and worsening of quality of life. To total of 1001 CAM were prescribed, 557 (55.6%) dronabinol as liquid, 328 (32.7%) as full spectrum extracts and 66 (6.6%) as oro-mucosal nabiximols spray. 50 prescriptions (5%) contained more than one CAM simultaneously. The daily consumption of dronabinol liquor and extracts were 9.6 mg/day (median), and of spray 13.6 mg. The dosage over time did not change in patients older than 64; in younger patients, there was a non-significant increasing trend. Women requested lower THC dosages compared to men (8.1 mg vs. 14.8 mg). Furthermore, 10 patients (5.6%) stopped CAM because of failing effectivity, 7 (3.9%) because of failing cost coverage and only 5 because of adverse side effects. 115 patients (65%) with CAM also received opioids a median 65 mg/day morphine equivalents. This opioid dosage was significantly reduced in course of time by 24 mg/day morphine equivalents or 50%. This reduction was independent on CAM dosage, age and gender. DISCUSSION: Patients with chronic pain profit from long-term CAM which safely and significantly lower the consumption of comedicated opioids, even at low dosages (< 7.5 mg/day). For women, low-dose THC may be sufficient. Older patients benefit from CAM, and adverse effects do not limit the (chronic) use and prescription of CAM in the elderly.


Assuntos
Canabinoides , Dor Crônica , Medicina Geral , Transtornos Relacionados ao Uso de Opioides , Masculino , Humanos , Feminino , Idoso , Idoso de 80 Anos ou mais , Analgésicos Opioides/efeitos adversos , Dronabinol/uso terapêutico , Canabinoides/uso terapêutico , Dor Crônica/tratamento farmacológico , Estudos Retrospectivos , Qualidade de Vida , Morfina/uso terapêutico
2.
Nature ; 523(7559): 236-9, 2015 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-25945741

RESUMO

Fundamental to all living organisms is the capacity to coordinate cell division and cell differentiation to generate appropriate numbers of specialized cells. Whereas eukaryotes use cyclins and cyclin-dependent kinases to balance division with cell fate decisions, equivalent regulatory systems have not been described in bacteria. Moreover, the mechanisms used by bacteria to tune division in line with developmental programs are poorly understood. Here we show that Caulobacter crescentus, a bacterium with an asymmetric division cycle, uses oscillating levels of the second messenger cyclic diguanylate (c-di-GMP) to drive its cell cycle. We demonstrate that c-di-GMP directly binds to the essential cell cycle kinase CckA to inhibit kinase activity and stimulate phosphatase activity. An upshift of c-di-GMP during the G1-S transition switches CckA from the kinase to the phosphatase mode, thereby allowing replication initiation and cell cycle progression. Finally, we show that during division, c-di-GMP imposes spatial control on CckA to install the replication asymmetry of future daughter cells. These studies reveal c-di-GMP to be a cyclin-like molecule in bacteria that coordinates chromosome replication with cell morphogenesis in Caulobacter. The observation that c-di-GMP-mediated control is conserved in the plant pathogen Agrobacterium tumefaciens suggests a general mechanism through which this global regulator of bacterial virulence and persistence coordinates behaviour and cell proliferation.


Assuntos
Ciclo Celular/fisiologia , Cromossomos/genética , GMP Cíclico/análogos & derivados , Replicação do DNA/genética , Agrobacterium tumefaciens/genética , Proteínas de Bactérias/metabolismo , Domínio Catalítico , Caulobacter crescentus/citologia , Ciclo Celular/genética , Divisão Celular/genética , Divisão Celular/fisiologia , Sequência Conservada , GMP Cíclico/metabolismo , Ciclinas/metabolismo , Modelos Moleculares , Monoéster Fosfórico Hidrolases/metabolismo , Fosfotransferases/química , Fosfotransferases/metabolismo , Ligação Proteica , Estrutura Terciária de Proteína
3.
Phys Rev Lett ; 123(19): 192302, 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31765208

RESUMO

Virtual Compton scattering on the proton has been investigated at three yet unexplored values of the four-momentum transfer Q^{2}: 0.10, 0.20, and 0.45 GeV^{2}, at the Mainz Microtron. Fits performed using either the low-energy theorem or dispersion relations allowed the extraction of the structure functions P_{LL}-P_{TT}/ε and P_{LT}, as well as the electric and magnetic generalized polarizabilities α_{E1}(Q^{2}) and ß_{M1}(Q^{2}). These new results show a smooth and rapid falloff of α_{E1}(Q^{2}), in contrast to previous measurements at Q^{2}=0.33 GeV^{2}, and provide for the first time a precise mapping of ß_{M1}(Q^{2}) in the low-Q^{2} region.

4.
Phys Rev Lett ; 119(2): 022001, 2017 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-28753336

RESUMO

The helicity-dependent recoil proton polarizations P_{x}^{'} and P_{z}^{'} as well as the helicity-independent component P_{y} have been measured in the p(e[over →],e^{'}p[over →])π^{0} reaction at four-momentum transfer Q^{2}≃0.1 GeV^{2}, center-of-mass proton emission angle θ_{p}^{*}≃90°, and invariant mass W≃1440 MeV. This first precise measurement of double-polarization observables in the energy domain of the Roper resonance P_{11}(1440) by exploiting recoil polarimetry has allowed for the extraction of its scalar electroexcitation amplitude at an unprecedentedly low value of Q^{2}, establishing a powerful instrument for probing the interplay of quark and meson degrees of freedom in the nucleon.

5.
Phys Rev Lett ; 114(23): 232501, 2015 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-26196794

RESUMO

At the Mainz Microtron MAMI, the first high-resolution pion spectroscopy from decays of strange systems was performed by electron scattering off a (9)Be target in order to study the Λ binding energy of light hypernuclei. Positively charged kaons were detected by a short-orbit spectrometer with a broad momentum acceptance at 0° forward angles with respect to the beam, efficiently tagging the production of strangeness in the target nucleus. Coincidentally, negatively charged decay pions were detected by two independent high-resolution spectrometers. About 10(3) pionic weak decays of hyperfragments and hyperons were observed. The pion momentum distribution shows a monochromatic peak at pπ≈133 MeV/c, corresponding to the unique signature for the two-body decay of hyperhydrogen Λ(4)H→(4)He+π(-), stopped inside the target. Its Λ binding energy was determined to be BΛ=2.12±0.01 (stat)±0.09 (syst)MeV with respect to the (3)H+Λ mass.

6.
Phys Rev Lett ; 112(22): 221802, 2014 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-24949757

RESUMO

A massive, but light, Abelian U(1) gauge boson is a well-motivated possible signature of physics beyond the standard model of particle physics. In this Letter, the search for the signal of such a U(1) gauge boson in electron-positron pair production at the spectrometer setup of the A1 Collaboration at the Mainz Microtron is described. Exclusion limits in the mass range of 40 MeV/c^{2} to 300 MeV/c^{2}, with a sensitivity in the squared mixing parameter of as little as ε^{2}=8×10^{-7} are presented. A large fraction of the parameter space has been excluded where the discrepancy of the measured anomalous magnetic moment of the muon with theory might be explained by an additional U(1) gauge boson.

7.
Klin Monbl Augenheilkd ; 231(10): 971-9, 2014 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-25333232

RESUMO

In spite of the self-limiting natural course of infantile haemangiomas of the eyelids and orbit, the effects of amblyopia, compression of the optic nerve, and impairment of the aesthetic appearance may develop. Since the serendipitous discovery of the effects of propranolol, a non-selective beta-blocker, on infantile haemangioma in 2008, it has largely replaced the former standard treatments with corticosteroids, laser or surgical procedures. This review discusses the pathogenesis, classification, indication for treatment, and treatment options for infantile haemangiomas. In addition, the results of patients with infantile haemangiomas of the eyelids and orbit treated with systemic propranolol are shown. With additional confirmation of data, including a positive effect-risk-analysis, propranolol will potentially replace high-dose corticosteroids and surgery in the treatment of infantile haemangiomas in the eyelids and orbit. Further clinical studies are necessary to optimise the dosage, treatment period, and application modalities (oral or topical). In the future, propranolol accompanied with paediatric-cardiological monitoring should emerge as the first-line therapy for problematic infantile haemangiomas.


Assuntos
Hemangioma/tratamento farmacológico , Hemangioma/patologia , Neoplasias Orbitárias/tratamento farmacológico , Neoplasias Orbitárias/patologia , Propranolol/uso terapêutico , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/patologia , Antagonistas Adrenérgicos beta/uso terapêutico , Feminino , Humanos , Recém-Nascido , Masculino
8.
Phys Rev Lett ; 111(13): 132504, 2013 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-24116774

RESUMO

A measurement of beam helicity asymmetries in the reaction 3He[over →](e[over →],e'n)pp is performed at the Mainz Microtron in quasielastic kinematics to determine the electric to magnetic form factor ratio of the neutron GEn/GMn at a four-momentum transfer Q2=1.58 GeV2. Longitudinally polarized electrons are scattered on a highly polarized 3He gas target. The scattered electrons are detected with a high-resolution magnetic spectrometer, and the ejected neutrons are detected with a dedicated neutron detector composed of scintillator bars. To reduce systematic errors, data are taken for four different target polarization orientations allowing the determination of GEn/GMn from a double ratio. We find µnGEn/GMn=0.250±0.058(stat)±0.017(syst).

9.
J Med Primatol ; 41(1): 60-6, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21967372

RESUMO

BACKGROUND: Nasopharyngeal colonization by Streptococcus pneumoniae precedes pneumococcal disease. Elucidation of procedures to prevent or eradicate nasopharyngeal carriage in a model akin to the human would help to diminish the incidence of both pneumonia and invasive pneumococcal disease. METHODS: We conducted a survey of the nasopharynx of infant rhesus macaques from our breeding colony, in search of natural carriers of S. pneumoniae. We also attempted experimental induction of colonization, by nasopharyngeal instillation of a human S. pneumoniae strain (19F). RESULTS: None of 158 colony animals surveyed carried S. pneumoniae in the nasopharynx. Colonization was induced in eight of eight infant rhesus by nasopharyngeal instillation and lasted 2weeks in 100% of the animals and 7weeks in more than 60%. CONCLUSION: Rhesus macaques are probably not natural carriers of S. pneumoniae. The high rate and duration of colonization obtained in our experiments indicates that the rhesus macaque will serve as a human-like carriage model.


Assuntos
Portador Sadio/veterinária , Macaca mulatta/microbiologia , Infecções Pneumocócicas/veterinária , Streptococcus pneumoniae/crescimento & desenvolvimento , Animais , Líquido da Lavagem Broncoalveolar/citologia , Líquido da Lavagem Broncoalveolar/microbiologia , Portador Sadio/microbiologia , Contagem de Colônia Microbiana , Masculino , Testes de Sensibilidade Microbiana , Nasofaringe/diagnóstico por imagem , Nasofaringe/microbiologia , Infecções Pneumocócicas/diagnóstico por imagem , Infecções Pneumocócicas/microbiologia , Radiografia
10.
Anaesthesia ; 67(6): 612-7, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22376088

RESUMO

The aim of our study was to evaluate the performance of different durations of active pre-operative skin-surface warming (pre-warming) to prevent peri-operative hypothermia and postoperative shivering. We randomly assigned 200 patients, scheduled for surgery of 30-90 min under general anaesthesia, to receive passive insulation or forced-air skin surface warming for 10, 20 or 30 min. Body temperature was measured at the tympanic membrane. Shivering was graded by visual inspection. There were significant differences in changes of core temperature between the non-pre-warmed group and all the pre-warmed groups (p < 0.00001), but none between the three pre-warmed groups (p = 0.54). Without pre-warming, 38/55 (69%) patients became hypothermic (< 36 °C) at the end of anaesthesia, whereas only 7/52 (13%), 3/43 (7%) and 3/50 (6%) patients following 10, 20 or 30 min pre-warming, respectively, became hypothermic (p < 0.001 vs no pre-warming). Shivering was observed in 10 patients without, and in three, three and one patients with pre-warming in the respective groups (p = 0.02). Pre-warming of patients for only 10 or 20 min before general anaesthesia mostly prevents hypothermia and reduces shivering.


Assuntos
Hipotermia/prevenção & controle , Complicações Intraoperatórias/prevenção & controle , Assistência Perioperatória/métodos , Complicações Pós-Operatórias/prevenção & controle , Adulto , Idoso , Anestesia Geral , Temperatura Corporal/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Medicação Pré-Anestésica , Estremecimento/fisiologia
11.
ScientificWorldJournal ; 2012: 373709, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22761550

RESUMO

BACKGROUND: Xenon seems to be an ideal anesthetic drug. To explore if next to the antagonism at the NMDA-receptor other molecular targets are involved, we tested the xenon requirement in short sleeping Drosophila shaker mutants and in na[har(38)]. METHODS: The Drosophila melanogaster strains wildtype Canton-S, na[har(38)], sh(102) and sh(mns), were raised and sleep was measured. Based on the response of the flies at different xenon concentrations, logEC50 values were calculated. RESULTS: The logEC50-values for WT Canton-S were 1.671 (1.601-1.742 95%-confidence intervall; n = 238; P versus sh(102) > 0,05), for sh(mns) 1.711 (1.650-1.773; n = 242; P versus WT Canton-S > 0,05). The logEC50-value for sh(102) was 1.594 (1.493-1.694; n = 261; P versus sh(mns) > 0.05). The logEC-value of na[har(38)] was 2.076 (1.619-2.532; n = 207; P versus sh(mns) < 0.05, versus sh(102) < 0.05, versus WT Canton-S < 0.05). P values for all shaker mutants were P > 0.05, while na[har(38)] was found to be hyposensitive compared to wildtype (P < 0.05). CONCLUSIONS: The xenon requirement in Drosophila melanogaster is not influenced by a single gene mutation at the shaker locus, whereas a reduced expression of a nonselective cation channel leads to an increased xenon requirement. This supports the thesis that xenon mediates its effects not only via an antagonism at the NMDA-receptor.


Assuntos
Proteínas de Drosophila/genética , Drosophila melanogaster/fisiologia , Receptores de N-Metil-D-Aspartato/metabolismo , Superfamília Shaker de Canais de Potássio/genética , Sono/efeitos dos fármacos , Sono/genética , Xenônio/farmacologia , Anestésicos Inalatórios/farmacologia , Animais , Mutação/genética
12.
Phys Rev Lett ; 106(25): 251802, 2011 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-21770630

RESUMO

A new exclusion limit for the electromagnetic production of a light U(1) gauge boson γ' decaying to e + e- was determined by the A1 Collaboration at the Mainz Microtron. Such light gauge bosons appear in several extensions of the standard model and are also discussed as candidates for the interaction of dark matter with standard model matter. In electron scattering from a heavy nucleus, the existing limits for a narrow state coupling to e + e- were reduced by nearly an order of magnitude in the range of the lepton pair mass of 210 MeV/c2}

13.
Phys Rev Lett ; 105(24): 242001, 2010 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-21231520

RESUMO

New precise results of a measurement of the elastic electron-proton scattering cross section performed at the Mainz Microtron MAMI are presented. About 1400 cross sections were measured with negative four-momentum transfers squared up to Q² = 1 (GeV/c)² with statistical errors below 0.2%. The electric and magnetic form factors of the proton were extracted by fits of a large variety of form factor models directly to the cross sections. The form factors show some features at the scale of the pion cloud. The charge and magnetic radii are determined to be ½ = 0.879(5)stat(4)syst(2)model(4)group fm and ½ = 0.777(13)stat(9)syst(5)model(2)group fm.

14.
Nat Commun ; 11(1): 6078, 2020 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-33247138

RESUMO

Understanding SARS-CoV-2 associated immune pathology is crucial to develop pan-effective vaccines and treatments. Here we investigate the immune events from the acute state up to four weeks post SARS-CoV-2 infection, in non-human primates (NHP) with heterogeneous pulmonary pathology. We show a robust migration of CD16 expressing monocytes to the lungs occurring during the acute phase, and we describe two subsets of interstitial macrophages (HLA-DR+CD206-): a transitional CD11c+CD16+ cell population directly associated with IL-6 levels in plasma, and a long-lasting CD11b+CD16+ cell population. Trafficking of monocytes is mediated by TARC (CCL17) and associates with viral load measured in bronchial brushes. We also describe associations between disease outcomes and high levels of cell infiltration in lungs including CD11b+CD16hi macrophages and CD11b+ neutrophils. Accumulation of macrophages is long-lasting and detectable even in animals with mild or no signs of disease. Interestingly, animals with anti-inflammatory responses including high IL-10:IL-6 and kynurenine to tryptophan ratios show less severe illness. Our results unravel cellular mechanisms of COVID-19 and suggest that NHP may be appropriate models to test immune therapies.


Assuntos
COVID-19/imunologia , Modelos Animais de Doenças , Pulmão/imunologia , SARS-CoV-2/imunologia , Doença Aguda , Animais , COVID-19/diagnóstico , COVID-19/patologia , COVID-19/virologia , Citocinas/metabolismo , Progressão da Doença , Feminino , Humanos , Pulmão/citologia , Pulmão/virologia , Macaca mulatta/imunologia , Macaca mulatta/virologia , Macrófagos/imunologia , Masculino , Monócitos/imunologia , Monócitos/metabolismo , Neutrófilos/imunologia , Neutrófilos/metabolismo , SARS-CoV-2/isolamento & purificação , Índice de Gravidade de Doença , Carga Viral/imunologia , Replicação Viral/imunologia
15.
Phys Rev Lett ; 103(15): 152501, 2009 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-19905628

RESUMO

Cross sections for the 3He(e,e' pn)1H reaction were measured for the first time at energy transfers of 220 and 270 MeV for several momentum transfers ranging from 300 to 450 MeV/c. Cross sections are presented as a function of the momentum of the recoil proton and the momentum transfer. Continuum Faddeev calculations using the Argonne V18 and Bonn-B nucleon-nucleon potentials overestimate the measured cross sections by a factor 5 at low recoil proton momentum with the discrepancy becoming smaller at higher recoil proton momentum.

17.
J Leukoc Biol ; 79(2): 257-67, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16443827

RESUMO

Cytosine-phosphate-guanine class C (CpG-C) immunostimulatory sequence oligodeoxynucleotides (ISS-ODNs) activate human B cells and dendritic cells (DCs), properties that suggest potential use as a novel adjuvant to enhance vaccine efficacy. After demonstrating that the CpG-C ISS-ODN C274 activates macaque DCs, we examined in vitro activation of macaque B cells by C274 as a prelude to evaluation of this molecule as an adjuvant in the testing of candidate human immunodeficiency virus vaccines in the rhesus macaque-simian immunodeficiency virus (SIV) model. C274 induced macaque CD20(+) B cells to proliferate more strongly than CD40 ligand or CpG-B ISS-ODN. C274 enhanced B cell survival; increased viability was most evident after 3-7 days of culture. Increased expression of CD40, CD80, and CD86 by B cells was apparent within 24 h of exposure to C274 and persisted for up to 1 week. C274-stimulated, B cell-enriched and peripheral blood mononuclear cell suspensions from naïve and immunodeficiency virus-infected monkeys secreted several cytokines [e.g., interleukin (IL)-3, IL-6, IL-12, interferon-alpha] and chemokines [e.g., monocyte chemoattractant protein-1/CC chemokine ligand 2 (CCL2), macrophage-inflammatory protein-1alpha/CCL3, IL-8/CXC chemokine ligand 8]. In comparison, exposure of macaque B cells to SIV had minimal impact on surface phenotype, despite inducing cytokine and chemokine production in cells from infected and uninfected animals. These observations emphasize the need to identify strategies to optimally boost immune function, as immunodeficiency viruses themselves only partially activate B cells and DCs. The ability of C274 to stimulate B cells and DCs in healthy and infected monkeys suggests its possible use as a broad-acting adjuvant to be applied in the rhesus macaque model for the development of preventative and therapeutic vaccines.


Assuntos
Vacinas contra a AIDS/farmacologia , Linfócitos B/efeitos dos fármacos , Infecções por HIV/imunologia , Oligodesoxirribonucleotídeos/farmacologia , Oligonucleotídeos/farmacologia , Vírus da Imunodeficiência Símia/imunologia , Animais , Linfócitos B/imunologia , Ligante de CD40/farmacologia , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Quimiocinas/imunologia , Doença Crônica , Citocinas/imunologia , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Modelos Animais de Doenças , Feminino , Técnicas In Vitro , Macaca mulatta , Masculino , Vírus da Imunodeficiência Símia/efeitos dos fármacos
18.
Dtsch Tierarztl Wochenschr ; 114(1): 12-5, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17252930

RESUMO

Caliciviruses are known to cause different diseases in many animal species. The bovine enteric caliciviruses (BEC) are associated with diarrhoea in cattle. These viruses have been classified in the genus Norovirus and are closely related to human noroviruses, the leading cause of gastroenteritis in humans. This has raised questions about zoonotic transmission and an animal reservoir for the human viruses. Two samples from 41 stool samples collected for diagnostic purposes from diarrheic cattle in Aulendorf, Germany tested positive for BEC. The samples were amplified with new degenerate BEC specific primers, which amplify a 263 bp portion of the RNA polymerase region. Analysis of the nucleotide sequences showed that these viruses are most closely related to the Norovirus genogroup III/2 (Bo/NLV/Newbury-2/76/UK) viruses.


Assuntos
Infecções por Caliciviridae/veterinária , Caliciviridae/isolamento & purificação , Doenças dos Bovinos/diagnóstico , Diarreia/veterinária , Animais , Sequência de Bases , Infecções por Caliciviridae/diagnóstico , Infecções por Caliciviridae/transmissão , Infecções por Caliciviridae/virologia , Bovinos , Doenças dos Bovinos/transmissão , Doenças dos Bovinos/virologia , Diarreia/diagnóstico , Diarreia/virologia , Reservatórios de Doenças/veterinária , Alemanha , Humanos , Dados de Sequência Molecular , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Zoonoses
19.
Biochim Biophys Acta ; 1280(2): 238-42, 1996 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-8639699

RESUMO

The effects of 4-hydroxy-3-nitrophenylglyoxal (HNPG), on the binding of eosin-5-maleimide (EMA), and diethyl pyrocarbonate (DEPC) to the anion transport system in the human red blood cell membrane, have been investigated. HNPG is a reversibly binding, arginine-specific, anion transport competitive inhibitor, known to act on the anion binding site. The EMA reaction site is an external facing lysine residue (Lys-430) in the 17 kDa transmembrane segment. The DEPC reaction site is an intracellular histidine (His-819) in the 35 kDa fragment. The results show that inhibition of the transport system with EMA increases in presence of HNPG to about 2.3 times. This finding suggests a positive cooperativity between the HNPG and EMA binding site and give evidence that the essential arginine is either nearby or allosterically linked to Lys-430. The inhibition of the cells with DEPC was nearly unchanged or slightly decreased in the presence of 10 mM HNPG. These results suggest that the intracellular His-residue which reacts with DEPC is not a part of the transport pathway. Our experiments with 4,4'-dinitrostilbene-2,2'-disulfonate (DNDS) have shown that its affinity to the transport system does not change after pre-treatment with phenylglyoxal (PG). We also found that the binding of [14C]phenylglyoxal (PG) to band 3 reduces significantly in presence of chloride. This is another evidence for the direct involvement of arginine residues in substrate binding.


Assuntos
Proteína 1 de Troca de Ânion do Eritrócito/metabolismo , Arginina/metabolismo , Membrana Eritrocítica/metabolismo , Proteína 1 de Troca de Ânion do Eritrócito/química , Arginina/química , Radioisótopos de Carbono , Dietil Pirocarbonato/química , Humanos , Fenilglioxal/química , Fenilglioxal/metabolismo , Ligação Proteica , Estilbenos/química
20.
Clin Pharmacol Ther ; 41(5): 490-5, 1987 May.
Artigo em Inglês | MEDLINE | ID: mdl-3552358

RESUMO

In a single-blind, placebo-controlled crossover study the effects of verapamil (450 +/- 30 mg/day) and propranolol (160 +/- 20 mg/day) on endurance time during submaximal exercise were compared in eight patients with essential hypertension. The drugs were given in randomized order. Each active drug period was preceded by a placebo phase. Endurance tests were performed during both placebo periods and treatment with verapamil and propranolol by bicycle ergometry. Both drugs were equally effective in decreasing resting blood pressure. Verapamil and propranolol reduced exercise heart rate, the effect of propranolol being more pronounced. With placebo, endurance time during exercise was 57 +/- 11 minutes; with propranolol it was 32 +/- 7 minutes (P less than 0.05). Verapamil had no influence on endurance time. The study demonstrates that in contrast to propranolol, verapamil has no influence on exercise tolerance during submaximal work in patients with hypertension.


Assuntos
Hipertensão/tratamento farmacológico , Resistência Física/efeitos dos fármacos , Propranolol/uso terapêutico , Verapamil/uso terapêutico , Adulto , Ensaios Clínicos como Assunto , Humanos , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Distribuição Aleatória
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