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1.
Acta Gastroenterol Belg ; 86(3): 499-501, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37814569

RESUMEN

Adenocarcinomas of the ampulla of Vater represent only 0.2% of all gastrointestinal cancers. Due to the low incidence no large clinical trials evaluating efficacy of treatments are available. Adjuvant therapy is often administered in patients with stage IB or higher. Oxaliplatin is considered as an effective and well tolerated therapeutic option. Adverse events associated with this therapy include cardio-, neuro-, nephrotoxicity and myelosuppression. Previously granulomatous pulmonary and liver manifestations have been described in oxaliplatin-based chemotherapy. In this report peritoneal manifestation of granulomatous disease associated with oxaliplatin is described for the first time. Sarcoidlike reactions may be misinterpreted as tumour progression or metastatic disease, and may consequently result in over-treatment.


Asunto(s)
Adenocarcinoma , Ampolla Hepatopancreática , Neoplasias del Conducto Colédoco , Enfermedades Peritoneales , Humanos , Oxaliplatino/efectos adversos , Ampolla Hepatopancreática/patología , Adenocarcinoma/patología , Neoplasias del Conducto Colédoco/tratamiento farmacológico , Neoplasias del Conducto Colédoco/etiología , Neoplasias del Conducto Colédoco/patología , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos
2.
Acta Gastroenterol Belg ; 84(2): 375-377, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34217192

RESUMEN

We report the case of a 59-year old man with portomesenteric venous gas (PMVG) due to inferior mesenteric vein fistulization caused by sigmoid diverticulitis with an unusual evolution. The patient initially presented with classic symptoms of lower abdominal pain and fever. Diagnosis of uncomplicated sigmoid diverticulitis was confirmed on computed tomography (CT) for which intravenous antibiotics were initiated. Hemocultures were positive for omnisensitive Escherichia Coli, but despite adequate intravenous antibiotic therapy, episodes of bacteraemia persisted and hemocultures remained positive. Repeat CT scan demonstrated regression of inflammation without signs of abcedation or perforation consistent with clinical findings. Endocarditis was excluded with a normal transoesophageal echocardiography. Finally, positron emission tomography-computed tomography (PET-CT) suspected a colovenous fistula and the presence of PMVG. The patient was successfully treated with laparoscopic sigmoidectomy. This case report summarises the diagnostic pathway and aims for higher awareness of non-ischemic PMVG causes.


Asunto(s)
Bacteriemia , Diverticulitis , Humanos , Masculino , Venas Mesentéricas , Persona de Mediana Edad , Tomografía Computarizada por Tomografía de Emisión de Positrones , Tomografía Computarizada por Rayos X
3.
B-ENT ; 10(4): 309-13, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25654956

RESUMEN

A 55-year-old woman was operated in the lateral park bench position with significant neck flexion and oral packing. Macroglossia was noticed immediately postoperatively after endotracheal extubation. The patient was reintubated for 13 days and subsequently required a tracheostoma. After the placement of the tracheostoma and the removal of the endotracheal tube, the congestion of the tongue decreased markedly within 24 hours. Macroglossia is a rare complication following posterior fossa procedures with few cases reported so far. It can cause airway obstruction, which could be a life-threatening complication, and it therefore requires prompt treatment. The aetiology of postoperative macroglossia remains uncertain and has been attributed to arterial, venous and lymphatic compression, mechanical compression, or neurogenic causes. This article describes new insights into aetiology and also describes preventive measures and possible treatment.


Asunto(s)
Obstrucción de las Vías Aéreas/etiología , Macroglosia/etiología , Neuroma Acústico/cirugía , Posicionamiento del Paciente/efectos adversos , Obstrucción de las Vías Aéreas/cirugía , Femenino , Humanos , Intubación Intratraqueal , Imagen por Resonancia Magnética , Persona de Mediana Edad , Neuroma Acústico/patología , Traqueostomía
4.
Global Spine J ; 2(4): 195-206, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24353968

RESUMEN

Aim To compare anterior fusion in standalone anterior lumbar interbody fusion (ALIF) using cage and screw constructs and anterior cage-alone constructs with posterior pedicle screw supplementation but without posterior fusion. Methods Eighty-five patients underwent single- or two-level ALIF procedure for degenerative disk disease or lytic spondylolisthesis (SPL). Posterior instrumentation was performed without posterior fusion in all cases of lytic SPL and when the anterior cage used did not have anterior screw through cage fixation. Results Seventy (82%) patients had adequate radiological follow-up at a mean of 19 months. Forty patients had anterior surgery alone (24 single level and 16 two levels) and 30 had front-back surgery (15 single level and 15 two levels). Anterior locked pseudarthrosis was only seen in the anterior surgery-alone group when using the STALIF cage (Surgicraft, Worcestershire, UK) (37 patients). This occurred in five of the single-level surgeries (5/22) and nine of the two-level surgeries (9/15). Fusion was achieved in 100% of the front-back group and only 65% (26/40) of the anterior surgery-alone group. Conclusion Posterior pedicle screw supplementation without posterolateral fusion improves the fusion rate of ALIF when using anterior cage and screw constructs. We would recommend supplementary posterior fixation especially in cases where more than one level is being operated.

5.
Eur Neurol ; 66(4): 210-4, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21934313

RESUMEN

We describe a patient who had four relapses of Miller Fisher syndrome over a period of 20 years. The classical triad - ophthalmoparesis, ataxia and areflexia - was present during the first two attacks; ataxia was not observed during the third episode. The final recurrence was characterized by signs suggestive of a central involvement of the oculomotor pathways, subclinical slowing of the visual-evoked potentials, and peripheral vestibular hyporeactivity. Brain imaging was normal, but high levels of anti-GQ1b IgG antibodies were detectable during the second relapse and persisted after the fourth recurrence despite complete clinical recovery.


Asunto(s)
Síndrome de Miller Fisher/complicaciones , Enfermedades Vestibulares/etiología , Adolescente , Pruebas Calóricas , Lateralidad Funcional , Humanos , Masculino , Movimientos Sacádicos , Vestíbulo del Laberinto/fisiopatología
6.
Pharm Res ; 26(3): 691-9, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18958404

RESUMEN

PURPOSE: To better understand the importance of the environmental conditions for drug release from biodegradable microparticles allowing for the development of more appropriate in vitro release measurement techniques. METHODS: Propranolol HCl diffusion in various agarose gels was characterized by NMR and UV analysis. Fick's law was used to theoretically predict the mass transport kinetics. Drug release from PLGA-based microparticles in such agarose gels was compared to that measured in agitated bulk fluids ("standard" method). RESULTS: NMR analysis revealed that the drug diffusivity was almost independent of the hydrogel concentration, despite of the significant differences in the systems' mechanical properties. This is due to the small size of the drug molecules/ions with respect to the hydrogel mesh size. Interestingly, the theoretically predicted drug concentration-distance-profiles could be confirmed by independent experiments. Most important from a practical point of view, significant differences in the release rates from the same batch of PLGA-based microparticles into a well agitated bulk fluid versus a semi-solid agarose gel were observed. CONCLUSION: Great care must be taken when defining the in vitro conditions for drug release measurements from biodegradable microparticles. The obtained new insight can help facilitating the development of more appropriate in vitro release testing procedures.


Asunto(s)
Materiales Biocompatibles/química , Portadores de Fármacos/química , Ácido Láctico/química , Modelos Teóricos , Preparaciones Farmacéuticas/administración & dosificación , Ácido Poliglicólico/química , Sefarosa/química , Transporte Biológico , Espectroscopía de Resonancia Magnética , Microscopía Electrónica de Rastreo , Tamaño de la Partícula , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Propranolol/administración & dosificación , Propranolol/farmacocinética , Propiedades de Superficie
7.
J Oral Rehabil ; 32(5): 368-74, 2005 May.
Artículo en Inglés | MEDLINE | ID: mdl-15842247

RESUMEN

Agar diffusion testing was used with four different media to evaluate the antibacterial activity of six products (one conventional glass-ionomer cement (GIC), two light-activated glass-ionomers, two polyacid-modified resin composites and one resin composite) on Streptoccoccus mutans. Their respective antibacterial activities were also compared during and after setting. The relationship between product acidity and antibacterial activity was evaluated. All the GICs demonstrated antibacterial properties in contrast to the polyacid-modified resin composites and resin composite which did not shown any antibacterial effects. Vitrebond GIC exhibited higher antibacterial action, probably because of a cytotoxic photo-initiator diphenyliodoniumchloride. A direct relationship between material acidity and growth inhibition of S. mutans was observed.


Asunto(s)
Antibacterianos , Compómeros , Resinas Compuestas , Cementos de Ionómero Vítreo , Boca/microbiología , Técnicas Bacteriológicas , Humanos , Concentración de Iones de Hidrógeno , Ensayo de Materiales
8.
Forensic Sci Int ; 143(2-3): 141-5, 2004 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-15240034

RESUMEN

Identification of glyphosate in four cases of poisoning, using nuclear magnetic resonance spectroscopy of biological fluids is reported. It has been performed by using a combination of 1H and 31P NMR analyses. Characterization of the N-(phosphonomethyl) glycine herbicide was achieved by chemical shift considerations and coupling constant patterns: CH2-(P) presents specific resonance at 3.12 ppm and appears as a doublet with a H-P characteristic coupling constant of 12.3 Hz. Moreover, resonances due to isopropylamine were present, confirming the ingestion of the considered trade formulation. After a calibration step, quantitation was performed by 1H and 31P NMR spectroscopy. The benefit and reliability of NMR investigations of biological fluids are discussed, particularly when the clinical picture is quite confusing.


Asunto(s)
Medicina Legal/métodos , Glicina/análogos & derivados , Glicina/análisis , Herbicidas/análisis , Espectroscopía de Resonancia Magnética/métodos , Adulto , Jugo Gástrico/química , Glicina/envenenamiento , Herbicidas/envenenamiento , Humanos , Hidrógeno , Modelos Lineales , Masculino , Persona de Mediana Edad , Fósforo , Glifosato
9.
Forensic Sci Int ; 133(1-2): 132-5, 2003 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-12742700

RESUMEN

In order to analyse a wide range of xenobiotics and their metabolites present in biological fluids, NMR spectroscopy can be used. A large variety of xenobiotics (therapeutic agents, pesticides, solvents, alcohols) can be characterized and quantitated directly, without sample preparation. NMR investigations were applied to acute poisoning cases, involving drugs such as salicylates and valproic acid (VPA). In a salicylate poisoning case, the three major metabolites of acetylsalicylic acid have been detected in crude urine, and rapid identification of lysine revealed the origin of the intoxication, namely lysine acetylsalicylate (Aspegic). Valproic acid as its glucuronide was identified in urine samples from two poisoned patients. 1H NMR was also used to identify and quantitate paraquat (Gramoxone) in urine owing to its two aromatic signals at 8.49 and 9.02 ppm, in two acutely poisoned patients (183 and 93 mg/l). An intentional poisoning case with tetrahydrofuran (THF) was also investigated. Serum and urine samples were collected. THF was characterized by its resonances at 1.90 and 3.76 ppm, and quantified at 813 and 850 mg/l in the two biological fluids, respectively. Moreover, two other compounds were detected: lactate and gamma-hydroxybutyric acid (GHB). 1H NMR spectroscopic analysis of serum samples from three poisoned patients revealed methanol in one case and ethylene glycol in the two others. Moreover, in the same spectrum, the corresponding metabolites formate and glycolate were found. Compared with the reference chromatographic or spectrophotometric methods, requiring time-consuming extraction and/or derivatization steps, NMR spectroscopy allows the determination of many exogenous and endogenous compounds, without any pre-selection of the analytes.


Asunto(s)
Espectroscopía de Resonancia Magnética , Xenobióticos/envenenamiento , Antiinflamatorios no Esteroideos/envenenamiento , Anticonvulsivantes/envenenamiento , Glicoles de Etileno/envenenamiento , Medicina Legal/métodos , Formiatos/sangre , Formiatos/envenenamiento , Furanos/envenenamiento , Hemostáticos/sangre , Hemostáticos/envenenamiento , Herbicidas/envenenamiento , Humanos , Metanol/envenenamiento , Paraquat/envenenamiento , Plaguicidas/envenenamiento , Salicilatos/envenenamiento , Solventes/envenenamiento , Ácido Valproico/envenenamiento , Ácido gamma-Aminobutírico/envenenamiento
10.
Photochem Photobiol ; 74(5): 694-9, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11723797

RESUMEN

The kinetic and structural behavior of a photochromic compound, 3-(2-fluorophenyl)-3-phenyl-3H-naphtho[2,1-b]pyran (F-Py), was investigated using 1H and 19F nuclear magnetic resonance (NMR) spectroscopy. Upon irradiation, the four theoretically predicted photomerocyanines appear along with a fifth form X, whose final structure has not been elucidated. This last form and two of the photomerocyanines are thermally labile, whereas the other two do not show any signs of decay. The system has been analyzed by NMR spectroscopy. This led to the structural assignment of each photomerocyanine. The kinetics of the thermal bleaching were monitored by directly and separately measuring the concentrations of each species at regular time intervals using 19F NMR spectroscopy. We therefore propose a plausible reaction mechanism. On the basis of this mechanism, the mathematical treatment and the study of the effects of temperature led to the determination of the kinetic and thermodynamic parameters (rate coefficients, enthalpy and entropy of activation) of this photochromic system. The leading role of the labile intermediate X on the formation of trans-transoid-cis (TTC) and cis-transoid-cis (CTC) photomerocyanines is pointed out.


Asunto(s)
Carbocianinas/química , Naftalenos/química , Fármacos Fotosensibilizantes/química , Piranos/química , Pirimidinonas/química , Cinética , Espectroscopía de Resonancia Magnética/métodos , Modelos Moleculares , Estructura Molecular
11.
J Anal Toxicol ; 25(4): 270-4, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11386640

RESUMEN

This article reports the investigation by 1H nuclear magnetic resonance (1H NMR) spectroscopy of biological fluids in a case of intentional poisoning with tetrahydrofuran (THF). Occupational exposures to this solvent are well documented, but acute poisoning cases are extremely rare, and the one presented here is the second known case of this kind. Urine and serum samples were collected. Without any pretreatment, the presence of THF was confirmed by characteristic resonances at 1.90 and 3.76 ppm; high lactate levels were also observed. The presence of gamma-hydroxybutyric acid (GHB) was noted. Quantitative analysis was performed by relative integration of peak areas. THF concentrations were 813 and 850 mg/L (11.3 and 11.8 mmol/L), and GHB concentrations 239 and 2,977 mg/L (2.3 and 28.6 mmol/L) in serum and urine, respectively. A gas chromatographic-mass spectrometric method confirmed 1H NMR observations. The origin of GHB detected in serum and urine is also discussed.


Asunto(s)
Furanos/envenenamiento , Espectroscopía de Resonancia Magnética , Enfermedad Aguda , Femenino , Furanos/sangre , Furanos/química , Furanos/orina , Cromatografía de Gases y Espectrometría de Masas , Humanos , Hidroxibutiratos/sangre , Hidroxibutiratos/orina , Ácido Láctico/sangre , Ácido Láctico/orina , Persona de Mediana Edad , Solventes/química , Solventes/envenenamiento , Análisis Espectral
12.
J Oral Rehabil ; 28(1): 26-32, 2001 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11298906

RESUMEN

The short and long-term fluoride release of 16 products (seven conventional glass-ionomers, five light-activated glass-ionomers, two polyacid-modified resin composites and two resin composites) commercialized as fluoride-releasing materials were measured. A potential link between the material type and its level of fluoride release was researched. The fluoride release was evaluated after different time intervals. Initial fluoride release from all materials was highest during the first 24 h and decreased sharply over the first week. Some groups of materials appeared to be significantly different after, respectively, 7 and 91 days. However, it was impossible to correlate the fluoride release of the materials by their type (conventional or resin-modified glass-ionomers, polyacid-modified resin composite and resin composite) except if we compared the products from the same manufacturer. The link between fluoride release and an acid-base reaction seems to be confirmed. The glass-ionomer composition (glass particles and polyacid's type, powder/liquid ratio) should have more influence on fluoride release than material type.


Asunto(s)
Cariostáticos/química , Compómeros/química , Resinas Compuestas/química , Fluoruros/química , Cementos de Ionómero Vítreo/química , Cementos de Resina/química , Ácidos/química , Resinas Acrílicas/química , Álcalis/química , Análisis de Varianza , Vidrio/química , Humanos , Maleatos/química , Ensayo de Materiales , Metacrilatos/química , Poliuretanos/química , Resinas Sintéticas/química , Silicatos/química , Factores de Tiempo
13.
MAGMA ; 10(3): 177-82, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10873209

RESUMEN

Analysis of biological fluids by proton and carbon nuclear magnetic resonance spectroscopy (1H and 13C NMR) is a promising tool in clinical biology. We used this method for rapid toxicological screening in the case of two suicide attempts. For each case, a urine sample was analysed at 300 MHz by 1D and 2D sequences (TOCSY and HMBC) in a short experimental time. Quantification was performed by peak integration on the 1D 1H NMR spectrum. For the two patients, results showed the same resonances of the major metabolite, valproyl-O-glucuronide at concentrations of 121 and 44 mmol/l.


Asunto(s)
Anticonvulsivantes/envenenamiento , Anticonvulsivantes/orina , Espectroscopía de Resonancia Magnética/métodos , Ácido Valproico/envenenamiento , Ácido Valproico/orina , Adolescente , Adulto , Anticonvulsivantes/metabolismo , Isótopos de Carbono , Sobredosis de Droga , Cromatografía de Gases y Espectrometría de Masas , Humanos , Hidrógeno , Masculino , Intento de Suicidio , Ácido Valproico/análogos & derivados , Ácido Valproico/metabolismo
14.
Planta ; 210(3): 446-53, 2000 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-10750903

RESUMEN

Nitrogen metabolism was monitored in suspension cultured cells of Nicotiana plumbaginifolia Viv. using nuclear magnetic resonance (NMR) spectroscopy following the feeding of (15NH4)2SO4 and K15NO3. By using two-dimensional 15N-1H NMR with heteronuclear single-quantum-coherence spectroscopy and heteronuclear multiple-bond-coherence spectroscopy sequences, an enhanced resolution of the incorporation of 15N label into a range of compounds could be detected. Thus, in addition to the amino acids normally observed in one-dimensional 15N NMR (glutamine, aspartate, alanine), several other amino acids could be resolved, notably serine, glycine and proline. Furthermore, it was found that the peak normally assigned to the non-protein amino-acid gamma-aminobutyric acid in the one-dimensional 15N NMR spectrum was resolved into a several components. A peak of N-acetylated compounds was resolved, probably composed of the intermediates in arginine biosynthesis, N-acetylglutamate and N-acetylornithine and, possibly, the intermediate of putrescine degradation into gamma-aminobutyric acid, N-acetylputrescine. The occurrence of 15N-label in agmatine and the low detection of labelled putrescine indicate that crucial intermediates of the pathway from glutamate to polyamines and/or the tobacco alkaloids could be monitored. For the first time, labelling of the peptide glutathione and of the nucleotide uridine could be seen.


Asunto(s)
Aminoácidos/metabolismo , Nicotiana/metabolismo , Plantas Tóxicas , Sulfato de Amonio/metabolismo , Células Cultivadas , Espectroscopía de Resonancia Magnética , Nitratos/metabolismo , Isótopos de Nitrógeno , Compuestos de Potasio/metabolismo , Ácido gamma-Aminobutírico/metabolismo
15.
J Anal Toxicol ; 23(7): 586-90, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10595844

RESUMEN

The application of 1H nuclear magnetic resonance (NMR) spectroscopy to characterize and quantitate paraquat in urine is described. Characterization was performed taking advantage of two NMR spectroscopy parameters: chemical shifts and coupling patterns. Without any pretreatment of the biological samples, herbicide was detected by its aromatic doublets at 8.49 and 9.02 ppm. Quantitation of the xenobiotic was realized by relative integration of the dipyridyl protons to an internal standard. After a validation step using control urine samples, quantitation was performed in urine obtained from two poisoned patients. On admission, mean paraquat concentrations were 985 (patient 1) and 500 (patient 2) micromol/L. Results are compared and found to be in good agreement, using a second-derivative spectroscopy method.


Asunto(s)
Herbicidas/envenenamiento , Herbicidas/orina , Espectroscopía de Resonancia Magnética/métodos , Paraquat/envenenamiento , Paraquat/orina , Adulto , Femenino , Humanos , Hidrógeno , Masculino , Persona de Mediana Edad , Intoxicación/diagnóstico , Intoxicación/orina , Reproducibilidad de los Resultados , Espectrofotometría Ultravioleta/métodos
16.
Acta Clin Belg ; 53 Suppl 1: 25-8, 1999.
Artículo en Francés | MEDLINE | ID: mdl-10216977

RESUMEN

Analysis of urine samples from two poisoned patients was performed using proton nuclear magnetic resonance (1H NMR) spectroscopy and a classical GC/MS protocol. Valproic acid as its glucuronide was identified and quantified in the 1H NMR spectra recorded directly from 0.5 mL of the collected samples. Moreover, a significant lactic aciduria could be observed. Comparison with the GC/MS findings suggests that 1H NMR spectroscopy can be clinically useful.


Asunto(s)
Anticonvulsivantes/envenenamiento , Anticonvulsivantes/orina , Cromatografía de Gases y Espectrometría de Masas/métodos , Espectroscopía de Resonancia Magnética/métodos , Detección de Abuso de Sustancias/métodos , Ácido Valproico/envenenamiento , Ácido Valproico/orina , Acidosis Láctica/inducido químicamente , Adolescente , Adulto , Anticonvulsivantes/química , Anticonvulsivantes/metabolismo , Glucuronatos/química , Glucuronatos/orina , Ácido Glucurónico , Humanos , Masculino , Intoxicación/diagnóstico , Reproducibilidad de los Resultados , Ácido Valproico/química , Ácido Valproico/metabolismo
17.
Acta Clin Belg ; 53 Suppl 1: 97-100, 1999.
Artículo en Francés | MEDLINE | ID: mdl-10216993

RESUMEN

By comparison of urine 1H NMR spectrum from a healthy person with those from poisoned patient, we have displayed one or several signals related to intoxication. In complement, various 1H and 13C NMR sequences in 1 and 2 dimensions (J-resolved, TOCSY, HMBC) were used to identify xenobiotic metabolites and quantify them in urine from patients poisoned with salicylate acetyl, chloroquine, valproïc acid, ethylene glycol and pesticides. NMR techniques provide a rapid determination on a small sample volume without pretreatment.


Asunto(s)
Espectroscopía de Resonancia Magnética/métodos , Intoxicación/diagnóstico , Intoxicación/orina , Adolescente , Adulto , Analgésicos/envenenamiento , Anticonvulsivantes/envenenamiento , Antimaláricos/envenenamiento , Aspirina/análogos & derivados , Aspirina/envenenamiento , Cloroquina/envenenamiento , Femenino , Humanos , Lisina/análogos & derivados , Lisina/envenenamiento , Masculino , Intoxicación/metabolismo , Reproducibilidad de los Resultados , Ácido Valproico/envenenamiento
18.
Toxicology ; 128(1): 73-81, 1998 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-9704907

RESUMEN

Analysis of serum and urine samples from three patients in a metabolic acidotic state was performed using biochemical methods and proton nuclear magnetic resonance (1H NMR). Methanol and ethylene glycol were identified by their singlet peaks in the 1H NMR spectra recorded directly from 0.5 ml of the collected samples. Quantification of these compounds was obtained simultaneously with that of their metabolites, formate and glycolate respectively and of lactate and ethanol, the latter being used as an antidote. The NMR results were found to be very similar to the biochemical findings. The results presented here suggest that 1H NMR can be clinically useful since it quickly provides information on the onset of metabolic acidosis and on the biotransformation of xenobiotics.


Asunto(s)
Glicoles de Etileno/envenenamiento , Metanol/envenenamiento , Intoxicación/diagnóstico , Acidosis/inducido químicamente , Acidosis/metabolismo , Adulto , Anciano , Biotransformación , Cromatografía de Gases , Glicoles de Etileno/farmacocinética , Femenino , Humanos , Espectroscopía de Resonancia Magnética , Masculino , Metanol/farmacocinética , Persona de Mediana Edad , Intoxicación/sangre , Intoxicación/orina
19.
Inorg Chem ; 37(21): 5418-5423, 1998 Oct 19.
Artículo en Inglés | MEDLINE | ID: mdl-11670683

RESUMEN

The disproportionation of aqueous hydrogen peroxide catalyzed by sodium tungstate has been investigated with regard to the multiplicity of the oxygen molecules released. Trapping experiments and detection of the IR luminescence of (1)O(2) have shown that the yield of (1)O(2) is virtually quantitative. The mono-, di-, and tetraperoxotungstate intermediates W(O(2))(n)()O(4)(-)(n)()(2)(-) (n = 1, 2, 4) have been characterized by UV and (183)W NMR spectroscopies. The diperoxo species is proposed as the precursor of (1)O(2).

20.
Rev Belge Med Dent (1984) ; 53(1): 278-94, 1998.
Artículo en Francés | MEDLINE | ID: mdl-10432827

RESUMEN

Clinical evaluation of anticariogenic potential of fluoride releasing materials seems to be the best way to evaluate products effectiveness. This is an expensive, lengthy and difficult process to realise. Yet there is a need to determine the relative effectiveness of different materials so that clinicians can make rational decision on what materials to use. Fluoride release measurement and fluoride uptake in dental tissues, antibacterial effect evaluation and caries-like lesion inhibition constitute a part of different model investigations use to study fluoride releasing materials. Even if the results of these different in vitro model systems may not be directly transposed to clinical reality, they give some useful information to determine anticariogenic potential of some dental materials. Three materials are analyzed: glass ionomer cements (conventional and resin-modified), polyacid modified resin composites and fluorated resin composites. Results obtained are different for the three kind of materials. Glass ionomer cements show much more anticariogenic properties than polyacid modified resin composites and fluorated resin composites. These two last products are more difficult to distinguish. It is probably due to their similar chemical properties. Even if these products don't have a large anticariogenic effect, it could be enough to prevent secondary caries. The anticariogenic action is principally due to the fluoride release of the materials. That's why it is necessary to define the acceptable level of fluoride release, which is required to have anticariogenic action.


Asunto(s)
Materiales Biocompatibles/química , Cariostáticos/administración & dosificación , Materiales Dentales/química , Fluoruros/administración & dosificación , Bacterias/efectos de los fármacos , Cariostáticos/química , Cariostáticos/farmacocinética , Resinas Compuestas/química , Caries Dental/prevención & control , Esmalte Dental/metabolismo , Dentina/metabolismo , Estudios de Evaluación como Asunto , Fluoruros/química , Fluoruros/farmacocinética , Cementos de Ionómero Vítreo/química , Humanos , Cementos de Resina/química
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