RESUMEN
A major myonecrotic zinc containing metalloprotease 'malabarin' with thrombin like activity was purified by the combination of gel permeation and anion exchange chromatography from T. malabaricus snake venom. MALDI-TOF analysis of malabarin indicated a molecular mass of 45.76 kDa and its N-terminal sequence was found to be Ile-Ile-Leu- Pro(Leu)-Ile-Gly-Val-Ile-Leu(Glu)-Thr-Thr. Atomic absorption spectral analysis of malabarin raveled the association of zinc metal ion. Malabarin is not lethal when injected i.p. or i.m. but causes extensive hemorrhage and degradation of muscle tissue within 24 hours. Sections of muscle tissue under light microscope revealed hemorrhage and congestion of blood vessel during initial stage followed by extensive muscle fiber necrosis with elevated levels of serum creatine kinase and lactate dehydrogenase activity. Malabarin also exhibited strong procoagulant action and its procoagulant action is due to thrombin like activity; it hydrolyzes fibrinogen to form fibrin clot. The enzyme preferentially hydrolyzes Aα followed by B subunits of fibrinogen from the N-terminal region and the released products were identified as fibrinopeptide A and fibrinopeptide B by MALDI. The myonecrotic, fibrinogenolytic and subsequent procoagulant activities of malabarin was neutralized by specific metalloprotease inhibitors such as EDTA, EGTA and 1, 10-phenanthroline but not by PMSF a specific serine protease inhibitor. Since there is no antivenom available to neutralize local toxicity caused by T. malabaricus snakebite, EDTA chelation therapy may have more clinical relevance over conventional treatment.
Asunto(s)
Quelantes/farmacología , Venenos de Crotálidos/antagonistas & inhibidores , Ácido Edético/farmacología , Hemorragia/tratamiento farmacológico , Metaloproteasas/antagonistas & inhibidores , Necrosis/tratamiento farmacológico , Mordeduras de Serpientes , Trimeresurus/fisiología , Animales , Antivenenos/química , Antivenenos/farmacología , Coagulación Sanguínea , Quelantes/química , Cromatografía en Gel , Creatina Quinasa/análisis , Creatina Quinasa/metabolismo , Venenos de Crotálidos/enzimología , Venenos de Crotálidos/toxicidad , Ácido Edético/química , Hemorragia/patología , Hemorragia/prevención & control , L-Lactato Deshidrogenasa/análisis , L-Lactato Deshidrogenasa/metabolismo , Masculino , Metaloproteasas/química , Metaloproteasas/aislamiento & purificación , Metaloproteasas/toxicidad , Ratones , Peso Molecular , Músculos/efectos de los fármacos , Músculos/patología , Necrosis/patología , Necrosis/prevención & control , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Zinc/metabolismoAsunto(s)
Glycyrrhiza/química , Hipertensión/inducido químicamente , Extractos Vegetales/efectos adversos , Plantas Medicinales , 11-beta-Hidroxiesteroide Deshidrogenasas , Relación Dosis-Respuesta a Droga , Ácido Glicirretínico/administración & dosificación , Ácido Glicirretínico/efectos adversos , Ácido Glicirretínico/farmacología , Glycyrrhiza/efectos adversos , Sustancias Peligrosas , Humanos , Hidroxiesteroide Deshidrogenasas/efectos de los fármacos , Isoenzimas/efectos de los fármacos , Riñón/metabolismo , Potasio/metabolismo , Sodio/metabolismoRESUMEN
BACKGROUND: The method used by granting agencies to select applications they wish to support should be explicit, consistent, and fair, especially when the applications are diverse and controversial in nature, or when funds are limited, which is often the case. This study demonstrates the use of a method to satisfy such standards. METHODS: An expert committee appointed by the Swiss National Research Foundation planned and advertised a program for the evaluation of alternative therapies. The selection of applications to be supported was assisted by the use of Judgement Analysis. In the first phase, appropriate standards such as relevance to the program objectives and methodological adequacy were established. In the second phase, the relative weights attached to these standards by individual members were obtained by multiple linear regression analysis. In the third phase, a single common policy based on the standards that had been made explicit was applied to the choice of projects to be supported. RESULTS: 219 grant applications that proposed a variety of alternative treatments for various indications were reviewed; 17 were funded. CONCLUSIONS: The method of Judgment Analysis was acceptable to the experts, who were drawn from several disciplines and had diverse points of view. The method proved understandable and easy to use.
Asunto(s)
Terapias Complementarias , Estudios de Evaluación como Asunto , Organización de la Financiación , Juicio , HumanosRESUMEN
11 beta-hydroxysteroid dehydrogenase (11 beta-OHSD) protects the non-selective renal mineralocorticoid receptor from the endogeneous glucocorticoid cortisol. Thus, drugs inhibiting 11 beta-OHSD might enhance urinary loss of potassium. In an attempt to find drugs inhibiting 11 beta-OHSD, 23 commonly used agents known to interfere with the potassium metabolism have been screened for inhibitory effect on 11 beta-OHSD. Furosemide appeared as the only inhibitor. Its inhibition constant (Ki) was 19.5 microM when kidney and 21.3 microM when liver microsomes were used as a source of 11 beta-OHSD. The type of inhibition was competitive. For confirmation that furosemide specifically inhibits 11 beta-OHSD, the complementary DNA (cDNA) of 11 beta-OHSD was transfected into COS-1 cells devoid of spontaneous expression of 11 beta-OHSD. In these cells, oxidation of corticosterone (Ki = 17.4 microM) and reduction of dehydrocorticosterone (Ki = 12.5 microM) was inhibited by furosemide. To establish whether this inhibition also occurs in vivo, the 11 beta-hydroxysteroid prednisolone was administered with and without furosemide to rats. The concentration ratio of prednisolone to its 11-ketometabolite prednisone increased in kidney and liver tissue after furosemide administration, indicating inhibition of 11 beta-OHSD. These data suggest that furosemide modulates in vivo the access of 11 beta-OH glucocorticoids to their target organs.
Asunto(s)
Furosemida/farmacología , Hidroxiesteroide Deshidrogenasas/antagonistas & inhibidores , 11-beta-Hidroxiesteroide Deshidrogenasas , Animales , Unión Competitiva , Línea Celular , Corticosterona/análogos & derivados , Corticosterona/metabolismo , ADN Complementario/genética , Hidroxiesteroide Deshidrogenasas/genética , Riñón/enzimología , Microsomas Hepáticos/enzimología , Oxidación-Reducción , Potasio/metabolismo , Prednisona/farmacología , Ratas , TransfecciónRESUMEN
The clinical, biochemical and radiological signs of uremic osteopathy in 25 patients dialyzed at the dialyzing unit of the Medical Policlinic of the University of Berne are described. Comparison, mainly of radiologic signs, with the published experience of other centers shows a relatively high frequency of nonsymptomatic osteopenia and metastatic and vascular calcifications in our patients, even though their serum calcium and phosphorous concentrations were kept relatively normal. The frequencies of radiologic alterations in other dialyzing units reported in the literature differ widely from one center to another; this may be due to different technology, but even more to varying evaluation of the findings by different radiologists.