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The crystal structures of the 1:1 complexes methylguanidinium benzylhydrogenmalonate, (C2N3H8)+(C10H9O4)?, MGD.BMAL, and methylguanidinium ethylhydrogenmalonate, (C2N3H8)+(C5H7O4)?, MGD.EMAL, and of the 2:1 complex methylguanidinium sulfate, (C2N3H8)2SO4, have been determined from three-dimensional X-ray data. For MGD.BMAL, the complex crystallizes in the triclinic space group P with two formula units in a cell of dimensions a = 6.277(5), b = 8.470(3), c = 13.191(6)Å, α= 91.01(1), β= 99.64(9), γ= 90.83(5)°. The structure has been refined to a final value of R = 0.061 based on 1511 intensities. The MGD.EMAL complex is also triclinic, space group P with two molecules in a cell of dimensions a = 9.254(7), b = 9.625(6), c = 6.778(2) Å, α= 109.6(1), β= 100.8(1), γ= 62.7(1)Å. The crystals of this compound are of low quality, and the final value is R = 0.109 based on 706 intensities. (MGD)2SO4 is orthorhombic, space group P212121, with four molecules in a cell of dimensions a = 7.100(4), b = 12.151(3), c = 13.108(2) Å. Refinement has converged to R = 0.054 based on 907 data. All three crystals exhibit extensive interionic hydrogen bonding. The hydrogen bonding in MGD.BMAL includes a Type B interaction and a Type 1 interaction, the latter being a pairwise interaction from both amino nitrogen atoms on the cation to two carboxylate oxygen atoms from the two different carboxylate groups in an anion. In MGD.EMAL, the anion participates in both a Type A and a Type B pairwise interaction with two neighboring cations. The possible implications of the hydrogen bonding patterns in these two compounds for the role of arginyl side chains in protection of γ-carboxyglutamate residues from decarboxylation are discussed. 相似文献
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Correlations between in Vitro and in Vivo Mechanisms of PyrethroidInsecticide Action. GAMMON, D. W. (1985). Fundam. Appl. Toxicol.5, 923. Classical neuropharmacological procedures havebeen used to elucidate insecticide mode of action in vitro.A good deal has thus been learned about pyrethroids but noveltechniques have been necessary to explain the toxicology andsymptomology. The free-walking, electrode-implanted cockroachtechnique, which was developed for this purpose, is described.It enabled correlations to be made between symptomology andeffects on specific nerves. The negative temperature coefficientof toxicity of allethrin (the first pyrethroid) was explainedin terms of repetitive firing in peripheral (sensory) nervesrather than by nerve blockage, which had been suggested fromprevious in Vitro studies. The elucidation of target sites invivo and the most useful parameter to study, i.e., repetitivefiring in nerve axons, enabled the definition of a pyrethroidresistance mechanism in a major insect pest. It also showedtwo modes of action for permethrin and cypermethrin, its -cyanoanalog. A structure-activity relationship for a range of pyrethroids,combining in Vitro and in Vivo approaches, confirmed two distincttypes of pyrethroid action. Studies of poisoning signs and nervedisruptions in Vivo in the mouse and cockroach, using diazepamin conjunction with pyrethroids, implicated the GABA-receptorcomplex as a target for -CN-phenoxybenzyl pyrethroids. Thiswas confirmed by making conductance measurements in crayfishclaw opener muscle fibers in Vitro. 相似文献
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JEFF S. HEALEY M.D. M.Sc. LORNE J. GULA M.D. DAVID H. BIRNIE M.D. LAWRENCE STERNS M.D. STUART J. CONNOLLY M.D. JOHN SAPP M.D. EUGENE CRYSTAL M.D. CHRIS SIMPSON M.D. DEREK V. EXNER M.D. M.P.H. TERESA KUS M.D. FRANCOIS PHILIPPON M.D. GEORGE WELLS Ph.D. ANTHONY SL. TANG M.D. 《Journal of cardiovascular electrophysiology》2012,23(12):1313-1316
Comparing ICD Implantation with and Without Intraoperative Defibrillation Testing. Introduction: The need to perform defibrillation testing (DT) at the time of implantable cardioverter defibrillator (ICD) insertion is controversial. In the absence of randomized trials, some regions now perform more than half of ICD implants without DT. Methods: During the last year of enrolment in the Resynchronization for Ambulatory Heart Failure Trial, a substudy randomized patients to ICD implantation with versus without DT. Results: Among 252 patients screened, 145 were enrolled; 75 randomized to DT and 70 to no DT. Patients were similar in terms of age (65.9 ± 9.3 years vs 67.9 ± 8.9 years); LVEF (24.7 ± 4.6% vs 23.6 ± 4.6%), QRS width (154.8 ± 23.5 vs 155.8 ± 23.6 ms), and history of atrial fibrillation (5% vs 6%). All 68 patients in the DT arm tested according to the protocol achieved a successful DT (≤25 J); 96% without requiring any system modification. No patient experienced perioperative stroke, myocardial infarction, heart failure (HF), intubation or unplanned ICU stay. The length of hospital stay was not prolonged in the DT group: 20.2 ± 26.3 hours versus 21.3 ± 23.0 hours, P = 0.79. One patient in the DT arm had a failed appropriate shock and no patient suffered an arrhythmic death. The composite of HF hospitalization or all‐cause mortality occurred in 10% of patients in the no‐DT arm and 19% of patients in the DT arm (HR = 0.53, 95% CI: 0.21–1.31, P = 0.14). Conclusions: In this randomized trial, perioperative complications, failed appropriate shocks, and arrhythmic death were all uncommon regardless of DT. There was a nonsignificant increase in the risk of death or HF hospitalization with DT. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1313‐1316, December 2012) 相似文献
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IAN APPLETON NICOLA J. BROWN DEAN WILLIS PAUL R. COLVILLE-NASH CHANDON ALAM JOANNE R. BROWN DEREK A. WILLOUGHBY 《The Journal of pathology》1996,180(1):90-94
Chronic granulomatous inflammation may be considered an angiogenic-dependent process. Recently it has been demonstrated that vascular endothelial growth factor (VEGF) or vascular permeability factor is essential for tumour angiogenesis. Its role in inflammation-mediated angiogenesis has yet to be determined. In this study, the murine chronic granulomatous air pouch model was used to investigate the role of VEGF in angiogenesis. Animals were treated twice weekly with 10 μ g per animal of neutralizing antibody to rh VEGF and the vascularity and granuloma dry weight were assessed after 7 days. This resulted in significant suppression of both angiogenesis and granuloma dry weight. Western blot analysis demonstrated the presence of VEGF; the levels of protein paralleled the angiogenic response. These results demonstrate for the first time that VEGF may be an important regulator of angiogenesis in inflammation. 相似文献
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SUZANNE F. ABRAHAM P. J. V. BEUMONT I. S. FRASER DEREK LLEWELLYN-JONES 《BJOG : an international journal of obstetrics and gynaecology》1982,89(7):507-510
Summary. A prospective study of the menstrual pattern and weight changes was made in the first year of training of 29 new female entrants to a professional ballet school. Seventy-nine per cent of the student girls had menstrual disturbances at entry: primary amenorrhoea, four; secondary amenorrhoea, 11; irregular menses, eight. The incidence of secondary amenorrhoea increase substantially by the end of the year (20), but was not associated with any significant change in body weight. Only three students menstruated regularly during the year. Menstrual regularity improved during periods of injury and long vacation and it appears that deterioration of the menstrual pattern during dancing periods was related to strenuous physical exercise rather than to any change in body weight. 相似文献
8.
MARILYN TAN MD ; DEREK ARMSTRONG MD ; CATHERINE BIRKEN MD ; ARI BITNUN MD ; CHRISTOPHER A CALDARONE MD ; PETER COX MB CHB ; WALTER KAHR MD PHD ; DAUNE MACGREGOR MD ; RAND ASKALAN PHD MD 《Developmental medicine and child neurology》2009,51(2):151-154
Thrombolysis is considered to be contraindicated in acute ischemic stroke secondary to infective endocarditis (IE). We report a 12-year-old female who presented with acute dense right hemiparesis and aphasia. Cranial magnetic resonance imaging and angiography showed multiple diffusion-restricted lesions in the left hemisphere and absence of flow in the left internal carotid artery. She was treated with intra-arterial tissue plasminogen activator within 6 hours of her presentation. Subsequently she was diagnosed with pneumococcal endocarditis and underwent debridement of vegetations and patch repair of the mitral valve. The patient did not have hemorrhagic complications following thrombolytic therapy or surgery. Pathological analysis of the mitral valve vegetations revealed mostly fibrin thrombus. Follow-up imaging showed complete recanalization of the left internal carotid artery, and the patient had a remarkable neurological recovery. This is the first case report of successful intra-arterial thrombolytic therapy in childhood IE-related stroke. We believe that thrombolytic therapy contributed to a favorable outcome in our patient and may be safe in selected patients with childhood IE-related acute ischemic stroke. 相似文献
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