RESUMEN
Although plant phosphate uptake is reduced by low soil temperature, arbuscular mycorrhizal (AM) fungi are responsible for P uptake in many plants. We investigated growth and carbon allocation of the AM fungus Glomus mosseae and a host plant (Plantago lanceolata) under reduced soil temperature. Plants were grown in compartmented microcosm units to determine the impact on both fungus and roots of a constant 2.7 °C reduction in soil temperature for 16 d. C allocation was measured using two (13)CO(2) pulse labels. Although root growth was reduced by cooling, AM colonization, growth and respiration of the extraradical mycelium (ERM) and allocation of assimilated (13)C to the ERM were all unaffected; the frequency of arbuscules increased. In contrast, root respiration and (13)C content and plant P and Zn content were all reduced by cooling. Cooling had less effect on N and K, and none on Ca and Mg content. The AM fungus G. mosseae was more able to sustain activity in cooled soil than were the roots of P. lanceolata, and so enhanced plant P content under a realistic degree of soil cooling that reduced plant growth. AM fungi may therefore be an effective means to promote plant nutrition under low soil temperatures.
Asunto(s)
Glomeromycota/fisiología , Micorrizas/fisiología , Plantago/fisiología , Transporte Biológico , Carbono/metabolismo , Dióxido de Carbono/análisis , Dióxido de Carbono/metabolismo , Isótopos de Carbono/análisis , Respiración de la Célula/fisiología , Frío , Glomeromycota/crecimiento & desarrollo , Micelio/crecimiento & desarrollo , Micorrizas/crecimiento & desarrollo , Fósforo/análisis , Fósforo/metabolismo , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/microbiología , Plantago/crecimiento & desarrollo , Plantago/microbiología , Suelo , Simbiosis , Agua , Zinc/análisis , Zinc/metabolismoRESUMEN
In this study, we evaluated the current effectiveness of 11 beta-lactam antibiotics for treatment of orofacial odontogenic infections by determining the antimicrobial susceptibility of the major pathogens. The antimicrobial susceptibilities of viridans streptococci (n = 47), Peptostreptococcus (n = 67), Porphyromonas (n = 18), Fusobacterium (n = 57), black-pigmented Prevotella (n = 59) and non-pigmented Prevotella (n = 47) isolated from pus specimens of 93 orofacial odontogenic infections to penicillin G, cefmetazole, flomoxef, cefoperazone, cefoperazone/sulbactam, ceftazidime, cefpirome, cefepime, cefoselis, imipenem and faropenem were determined using the agar dilution method. Penicillin G, most cephalosporins, imipenem and faropenem worked well against viridans streptococci, Peptostreptococcus, Porphyromonas and Fusobacterium. Penicillin G and most cephalosporins, including fourth-generation agents, were not effective against beta-lactamase-positive Prevotella, though they were effective against beta-lactamase-negative strains. Cefmetazole, cefoperazone/sulbactam, imipenem and faropenem expressed powerful antimicrobial activity against beta-lactamase-positive Prevotella. In conclusion, penicillins have the potential to be first-line agents in the treatment of orofacial odontogenic infections. Most of the other beta-lactam antibiotics, including fourth-generation cephalosporins, were not found to have greater effectiveness than penicillins. In contrast, cefmetazole, cefoperazone/sulbactam, imipenem and faropenem were found to have greater effectiveness than penicillins.
Asunto(s)
Antibacterianos/uso terapéutico , Bacterias/efectos de los fármacos , Infecciones Bacterianas/tratamiento farmacológico , Ceftizoxima/análogos & derivados , Lactamas , Enfermedades de la Boca/microbiología , beta-Lactamas , Infecciones por Bacteroidaceae/tratamiento farmacológico , Cefepima , Cefmetazol/uso terapéutico , Cefoperazona/administración & dosificación , Cefoperazona/uso terapéutico , Ceftazidima/uso terapéutico , Ceftizoxima/uso terapéutico , Cefalosporinas/uso terapéutico , Farmacorresistencia Bacteriana , Quimioterapia Combinada/uso terapéutico , Fusobacterium/efectos de los fármacos , Infecciones por Fusobacterium/tratamiento farmacológico , Infecciones por Bacterias Grampositivas/tratamiento farmacológico , Humanos , Imipenem/uso terapéutico , Pruebas de Sensibilidad Microbiana , Enfermedades de la Boca/tratamiento farmacológico , Penicilina G/uso terapéutico , Penicilinas/uso terapéutico , Peptostreptococcus/efectos de los fármacos , Porphyromonas gingivalis/efectos de los fármacos , Prevotella/efectos de los fármacos , Infecciones Estreptocócicas/tratamiento farmacológico , Streptococcus/efectos de los fármacos , Sulbactam/administración & dosificación , Sulbactam/uso terapéutico , CefpiromaRESUMEN
OBJECTIVE: The aim of this study was to obtain information for an effective antimicrobial therapy against orofacial odontogenic infections; such information was obtained from recent bacteriologic features and antimicrobial susceptibility data. STUDY DESIGN: The bacteriology and antimicrobial susceptibility of major pathogens in 163 patients with orofacial odontogenic infections to 7 antibiotics was examined. RESULTS: Mixed infection of strict anaerobes with facultative anaerobes (especially viridans streptococci) was observed most often in dentoalveolar infections, periodontitis, and pericoronitis. Penicillin (penicillin G) was effective against almost all pathogens, although it did not work well against beta-lactamase-positive Prevotella. Cefmetazole was effective against all test pathogens. Erythromycin was ineffective against viridans streptococci and most Fusobacterium. Clindamycin exerted a strong antimicrobial activity on anaerobes. Minocycline was effective against almost all the test pathogens. The antimicrobial activity of levofloxacin against viridans streptococci was not strong. CONCLUSIONS: An antibiotic that carries out antimicrobial activity against both viridans streptococci and oral anaerobes should be suitable for treatment of dentoalveolar infection, periodontitis, and pericoronitis. Penicillin remains effective as an antimicrobial against most major pathogens in orofacial odontogenic infections. Cefmetazole, clindamycin, and minocycline may be effective against most pathogens, including penicillin-unsusceptible bacteria.
Asunto(s)
Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Bacterias Anaerobias/efectos de los fármacos , Infecciones Bacterianas/microbiología , Enfermedades de la Boca/microbiología , Streptococcus/efectos de los fármacos , Infecciones Bacterianas/tratamiento farmacológico , Cefmetazol/farmacología , Distribución de Chi-Cuadrado , Clindamicina/farmacología , Farmacorresistencia Microbiana , Eritromicina/farmacología , Humanos , Pruebas de Sensibilidad Microbiana , Minociclina/farmacología , Enfermedades de la Boca/tratamiento farmacológico , Penicilinas/farmacología , Penicilinas/uso terapéutico , Absceso Periapical/microbiología , Pericoronitis/microbiología , Absceso Periodontal/microbiología , Periodontitis/microbiología , Prevotella/efectos de los fármacos , Prevotella/metabolismo , beta-Lactamasas/biosíntesisRESUMEN
A 68-year-old man presented with multiple hepatocellular carcinoma, which was considered to be unresectable at the first admission in January 1994. Pathological diagnosis was made by biopsy of the one lesion among them. From January 1994 to December 1997, 10 transarterial chemoembolizations and six percutaneous ethanol injection therapies were performed on the tumours in the cirrhotic liver. In February 1998 the tumour situated in the right lobe began to increase in size. The maximum tumour diameter was 6.3 cm measured by computed tomography (CT). In the beginning of May 1998 moderate ascites was present and mild hepatic encephalopathy was noticed. The patient was in the terminal stage of hepatocellular carcinoma and no further treatment was possible at that time. However, serum alpha-fetoprotein and protein induced by vitamin K absence or antagonist II dramatically decreased in June 1998. The CT scan also showed that the tumour had completely regressed without specific treatment. In February 1999 a new biopsy-proven hepatocellular carcinoma, 2 cm in diameter, developed in the lateral segment of the liver. It was well treated by percutaneous ethanol injection therapy. The patient was alive in good condition without any symptoms or tumour recurrence in June 1999. It was concluded that a rare case of spontaneous regression of hepatocellular carcinoma had occurred.
Asunto(s)
Carcinoma Hepatocelular/patología , Neoplasias Hepáticas/patología , Anciano , Síndrome de Budd-Chiari , Carcinoma Hepatocelular/terapia , Terapias Complementarias , Embolización Terapéutica/métodos , Etanol/uso terapéutico , Hepatitis C Crónica/complicaciones , Humanos , Hígado/patología , Neoplasias Hepáticas/terapia , Masculino , Remisión Espontánea , Análisis de Supervivencia , Tomografía Computarizada por Rayos X , alfa-Fetoproteínas/análisisRESUMEN
Supplementation of a carbohydrate-free minimal medium with a high level (100 mM) of histidine, methionine, valine, isoleucine, proline and leucine, in particular isoleucine, markedly increased toxin production by Clostridium difficile VPI 10463. The effect of isoleucine was further examined. Increasing the concentration of isoleucine from 20 to 100 mM remarkably increased toxin production, while bacterial growth decreased gradually. Amino acid analysis of the culture revealed that, at 100 mM isoleucine, consumption of isoleucine was remarkably increased. During the incubation period when toxin titers increased markedly but bacterial growth was declining, isoleucine, leucine and cysteine were taken up preferentially and alanine and cystathionine, which were not found at 1 mM isoleucine, were produced in large quantities. These findings suggest that isoleucine may play an important role in toxin production by C. difficile and that alanine and cystathionine production may be co-regulated with the toxin production in the absence of fermentable carbohydrates.
Asunto(s)
Proteínas Bacterianas , Toxinas Bacterianas/biosíntesis , Clostridioides difficile/metabolismo , Enterotoxinas/biosíntesis , Isoleucina/metabolismo , Aminoácidos , Clostridioides difficile/efectos de los fármacos , Medios de Cultivo , Relación Dosis-Respuesta a Droga , Isoleucina/farmacología , Factores de TiempoRESUMEN
Effects of monatepil ([(+/-)-N-(6,11-dihydrodibenzo[b, e]thiepin-11-yl)-4-(p-fluorophenyl)-1-piperazinebutyramide]m aleate, AJ-2615, CAS 103377-41-9), a novel calcium antagonist, on the cardiac conduction system were compared by electrocardiography with those of the existing calcium antagonists (diltiazem, verapamil and nifedipine) in isolated rabbit heart preparations in vitro and in anesthetized and conscious dogs in vivo. Monatepil (10(-7) mol/l) prolonged the atrio-His bundle conduction time (AH interval) in the Langendorff perfused rabbit heart, like diltiazem, verapamil and nifedipine. This prolongation was decreased to 1/10 in the presence of 3.6% bovine serum albumin. In anesthetized dogs, monatepil (0.1-1.0 mg/kg i.v.), unlike diltiazem and verapamil, did not prolong AH interval. In conscious dogs, monatepil even at 100 mg/kg p.o. did not affect electrocardiograms. At the high dose of 300 mg/kg p.o., only a slight prolongation of the QT interval was found, but the QTc interval was not affected. Diltiazem at 10 mg/kg p.o. caused a prolongation of the PR interval and a disappearance of QRS waves. In conscious renal hypertensive dogs, repeated administration of monatepil (10 mg/kg/d p.o. for 29 days) had little effect on the conduction system of the heart examined by electrocardiograms, albeit a persistent fall in blood pressure continued throughout the administration period. The above results suggest that monatepil is a highly safe drug in the treatment of hypertension.