Sex and age-related differences in perceived, desired and measured percentage body fat among adults.

BACKGROUND: Body image distortion/discrepancy leads to psychological stress, disordered eating and mental and physical disease. To begin to assess body image distortion/discrepancy, we compared perceived, desired and measured percentage body fat in male versus female and college-aged versus non-college aged individuals. In addition, we assessed the acute stress response to body composition measurement. METHODS: Body fat percentage of 15 college aged ('College Students'; CS) (mean = 19 years) and 16 non-college aged ('Non-College Aged Students'; NCS) (mean = 39 years) males and females was assessed with the BodPod Body Composition Tracking System (Life Measurement Instruments, Concord, CA, USA). Participants indicated their perception of body fat and their desired body fat using a somatomorphic matrix. Salivary cortisol, heart rate and blood pressure were also measured. Data were analysed by analysis of variance and alpha was set at 0.05. RESULTS: Mean (SD) percentage body fat of males [15.2% (6.1%)] was significantly lower than that of females [28.4% (6.4%)] (P < 0.0001). Both CS and NCS females perceived their body fat to be lower (5%) than measured body fat and desired their body fat to be lower (12%) than measured (P < 0.05). CS and NCS male participants demonstrated the opposite result; both CS and NCS male populations perceived their body fat to be higher (5%) than measured body fat and desired their body fat to be higher (4%) than measured (P < 0.05). No differences between any groups were observed in heart rate, blood pressure or cortisol response to body fat measurement. CONCLUSIONS: Sex-related but not age-related differences in perceived, desired and measured percentage body fat were observed.

Minocycline increases the life span and motor activity and decreases lipid peroxidation in manganese treated Drosophila melanogaster.

The objective of this study was to investigate the effect of Minocycline in the life span, motor activity, and lipid peroxidation of Drosophila melanogaster treated with manganese. Two days after emerging from the pupa male wild-type D. melanogaster were fed for 13 days with corn media containing 15 mM manganese. Then, they were divided in six groups of 300 flies each: group (a) remained treated with manganese (Mn group); group (b) began treatment with Minocycline (0.05 mM) (Mn-Minocycline group); group (c) received no additional treatment (Mn-no treatment group); group (d) simultaneously fed with manganese and Minocycline (Mn+Minocycline group). Additionally, a control (group e) with no treatment and another group (f) fed only with Minocycline after emerging from the pupa were added. All the manganese treated flies (group a) were dead on the 25th day. The life span in group f (101.66±1.33 days, mean S.E.M.) and of group b (97.00±3.46 days) were similar, but in both cases it was significantly higher than in group e (68.33±1.76 days), group c (67.05±2.30 days) and in those of group d (37.33±0.88). Manganese (groups a and d) decreased motor activity in D. melanogaster. In the Minocycline fed flies (groups b and f) a higher motor activity was detected. In Mn-Minocycline and Mn+Minocycline treated flies a significant decrease of MDA levels was detected when compared to the Minocycline group indicating that Minocycline and Mn appear to have a synergistic effect. In conclusion, Minocycline increased the life span and motor activity and decreased MDA formation of manganese treated D. melanogaster, probably by an inhibition of the production of reactive oxygen species. Manganese also exerted an antioxidant effect as shown by the significant decrease of MDA levels when compared to control flies.

El GES promueve la equidad en el tratamiento del gran quemado de la tercera edad / Analysis of the explicit guarantees of health inclusion criteria for elderly burned patients

Background: The guidelines for the treatment of severely burned patients, ineluded in the explicit guarantees in health care (GES), accept having a Garces' index over 70, among others, as an inclusion criterion. This criterion allows elderly patients with small total burn surface area (TBSA) to have access to GES. Aim: To analyze if a universal access to GES for this group of patients is justified. Material and Methods: Revision of medical records of adult patients admitted to a burn service. Causative agent, TBSA, associated illnesses and outcome were compared between 218 subjects aged 65 years or more and 720 subjects aged less than 65 years. Results: Older subjects had smaller TBSA, a lower prevalence of inhalation injury and more associated diseases. Their lethality was three times greater than that of younger subjects and their risk of dying. When adjusting for TBSA, presence of inhalation injury and associated diseases was 11 times greater. Conclusions: The inclusion of older people with lower TBSA in the explicit guarantees in health is fully justified, considering the lethality of burns in this age group.

[Analysis of the explicit guarantees of health inclusion criteria for elderly burned patients]. / El GES promueve la equidad en el tratamiento del gran quemado de la tercera edad.

BACKGROUND: The guidelines for the treatment of severely burned patients, included in the explicit guarantees in health care (GES), accept having a Garces' index over 70, among others, as an inclusion criterion. This criterion allows elderly patients with small total burn surface area (TBSA) to have access to GES. AIM: To analyze if a universal access to GES for this group of patients is justified. MATERIAL AND METHODS: Revision of medical records of adult patients admitted to a burn service. Causative agent, TBSA, associated illnesses and outcome were compared between 218 subjects aged 65 years or more and 720 subjects aged less than 65 years. RESULTS: Older subjects had smaller TBSA, a lower prevalence of inhalation injury and more associated diseases. Their lethality was three times greater than that of younger subjects and their risk of dying. When adjusting for TBSA, presence of inhalation injury and associated diseases was 11 times greater. CONCLUSIONS: The inclusion of older people with lower TBSA in the explicit guarantees in health is fully justified, considering the lethality of burns in this age group.

Mortalidad tras un año de protocolización en el manejo del paciente quemado / Effects of standarization of burn patient treatment on mortality

Background: In 2006, the burn unit of an emergency public hospital in Chile standardized its medical and surgical treatment protocols. Aim: To analyze the evolution of mortality among patients admitted to the unit after the standardization process. Material and Methods: Patients admitted to the unit between March 2005 and March 2006, were analyzed. An early surgical debridement was performed, according to the guide-lines, after a standardized reanimation with Lactate Ringer using Parkland formula (4 ml/kg/ percent burn surface area). All patients were monitored. An algorithm was used to decide the indication of vasoactive drugs or invasive monitorization. Results: Eighty eight patients aged 43 +/- 19 years (65 percent males) were admitted. The estimated percentage body burned was 30 +/- 21 percent, deep in 12.5 +/- 17 percent. A mean of 9.122 +/- 6.930 mi of fluid were administered in the first 24 hours. The first surgical debridement was performed at 48 hours (range 1 to 15 days). The first escharotomy was performed at 4.2 days (range 3 hours -15 days), the first covering at 3.8 days (range 3 hours-19 days) the first auto graft at 18 days (range 4-26 days). Operative times in the first three surgical procedures were less than 87 min. Global mortality was 37 percent. Conclusions: The standardized treatment of burns resulted in an absolute reduction of mortality.

Introducción: En el 2005 el Servicio de Quemados del HUAP inició un proceso de modernización. Durante el primer año se intervino en el protocolo terapéutico médico y quirúrgico. Se analizarán la mortalidad observada en este período. Materiales y Métodos: Se analizaron los pacientes admitidos en Cuidados Intermedios e Intensivos de nuestra unidad desde el Iº de marzo de 2005 a Iº de marzo de 2006. Se realizó aseo quirúrgico precoz, según protocolo, previa reanimación estandarizada con Ringer Lactato usando la fórmula de Parkland, 4 cc/kg/ por ciento SCT (superficie corporal total). Todos los casos fueron monitorizados, guiados por diuresis y con algoritmo para decidir inicio de drogas vasoactivas o monitorización invasiva. Resultados: Ingresan 88 pacientes, 58 por ciento trasladados de otros centros. Edad promedio 43 +/- 18,9 años; hombres 65 por ciento, mujeres 35 por ciento; superficie corporal quemada 30 +/- 21 por ciento, profunda 12,5 +/- 17 por ciento. Se administró en promedio 9.122 +/- 6.930 ce durante las primeras 24 hrs. Primer aseo se realizó a las 48 hrs (1 hr -15 días), Ia escarectomía a los 4,2 días (3 hrs - 15 días), Ia cobertura a los 3,8 días (3 hrs - 19 días), 1er autoinjerto a los 18 días (4 - 26 días). Tiempos operatorios promedio en las 3 primeras cirugías inferiores a 87 min. Mortalidad absoluta disminuyó a 19 por ciento. Mortalidad global 37 por ciento. Conclusiones: Luego del primer año del proceso de modernización, con reanimación estandarizada, equipos quirúrgicos proporcionales a la SCT quemada con disminución de los tiempos quirúrgicos, asociado a un manejo multidisciplinario, se logró una disminución de la mortalidad global.

[Transthoracic echocardiography in stroke performed by neurologist: pilot study]. / Ecocardiografía transtorácica realizada por neurólogos en patología vascular: estudio piloto.

INTRODUCTION: The aim of this study is to assess concordance between transthoracic echocardiography (TTE) performed by neurologists and cardiologists for the screening of cardioembolic sources in patients with ischemic stroke. METHODS: We examined prospectively 27 consecutive patients with ischemic stroke. A potential source of embolism in all of the patients was sought by means of a TTE study. This study was performed by one neurologist after one-month full-time training on the technique and independently by one cardiologist whose results were considered as the reference standard. Regarding the risk of cardioembolism, findings from TTE studies were considered as normal, or indicative of either moderate or high risk, according to the TOAST criteria. Agreement between the two observers on the diagnosis of cardioembolic source was analyzed with the Cohen's Kappa Test (K). A K > 0,6 was considered as good agreement. RESULTS: The 27 patients studied had a mean age of 68,7 +/- 10,2 years and 70 % were men. A cardioembolic source was detected in 9 patients by the cardiologist and 8 of these were also identified by the neurologist: in 1 patient a mitral annulus calcification was not detected in the examination performed by the neurologist. In 2 patients with poor echocardiographic window, the neurologist underestimated the left ventricular function. Diagnostic agreement between both examinations was 88,9 % (K: 0,77; p = 0,001). CONCLUSION: Compared with cardiologists, trained neurologists show a fairly high degree of accuracy in the TTE screening of patients with stroke. Those cases with poor echocardiographic window or with abnormal findings should be confirmed by the cardiologists.

Ecocardiografía transtorácica realizada por neurólogos en patología vascular: estudio piloto / Transthoracic echocardiopraphy in stroke performed by neurologist: pilot study

El objetivo de nuestro estudio es comparar la concordancia entre la ecocardiografía transtorácica (ETT) realizada por neurólogos y cardiólogos en el cribado de fuentes cardioembólicas en pacientes con isquemia cerebral. Métodos. Evaluamos de forma prospectiva y consecutiva 27 pacientes con isquemia cerebral. A todos se les realizó una ETT por un neurólogo que había sido entrenado previamente durante un mes en la técnica, e independientemente, por un cardiólogo cuyos resultados fueron considerados como la referencia estándar. Según el riesgo de cardioembolismo, los hallazgos en la ETT fueron clasificados como normales, de moderado o alto riesgo según los criterios TOAST. La concordancia en el diagnóstico de fuente cardioembólica entre ambos exploradores fue evaluado con el test Kappa de Cohen (K). Una K>0,6 se consideró como buena concordancia. Resultados. De 27 pacientes con isquemia cerebral, la edad media fue de 68,7 ± 10,2 años y 70 % fueron hombres. En 9 pacientes el cardiólogo detectó una fuente cardioembólica, y de ellos, 8 pacientes también por el neurólogo (1 paciente con calcificación del anillo mitral no fue detectado). En 2 pacientes con mala ventana ecocardiográfica, el neurólogo infraestimó la función ventricular. El diagnóstico fue concordante entre ambas exploraciones en un 88,9 % de los pacientes (K: 0,77; p = 0,001). Conclusiones. Comparado con el cardiólogo, un neurólogo entrenado realiza la ETT con una buena fiabilidad. En los casos con mala ventana ecocardiográfica o con hallazgos patológicos, éstos deberían ser confirmados por el cardiólogo (AU)

Introduction. The aim of this study is to assess concordance between transthoracic echocardiography (TTE) performed by neurologists and cardiologists for the screening of cardioembolic sources in patients with ischemic stroke. Methods. We examined prospectively 27 consecutive patients with ischemic stroke. A potential source of embolism in all of the patients was sought by means of a TTE study. This study was performed by one neurologist after one-month full-time training on the technique and independently by one cardiologist whose results were considered as the reference standard. Regarding the risk of cardioembolism, findings from TTE studies were considered as normal, or indicative of either moderate or high risk, according to the TOAST criteria. Agreement between the two observers on the diagnosis of cardioembolic source was analyzed with the Cohen's Kappa Test (K). A K > 0,6 was considered as good agreement. Results. The 27 patients studied had a mean age of 68,7 ± 10,2 years and 70 % were men. A cardioembolic source was detected in 9 patients by the cardiologist and 8 of these were also identified by the neurologist: in 1 patient a mitral annulus calcification was not detected in the examination performed by the neurologist. In 2 patients with poor echocardiographic window, the neurologist underestimated the left ventricular function. Diagnostic agreement between both examinations was 88,9 % (K: 0,77; p = 0,001). Conclusion. Compared with cardiologists, trained neurologists show a fairly high degree of accuracy in the TTE screening of patients with stroke. Those cases with poor echocardiographic window or with abnormal findings should be confirmed by the cardiologists (AU)

GNAS1 T393C polymorphism is associated with migraine.

Migraineurs have an interictal sympathetic nervous system (SNS) hypofunctionality and hypersensitivity to adrenergic amines. The GNAS1 T393C polymorphism has been associated with a distinct SNS sensitivity in healthy subjects. We tested GNAS1 T393C variant in two independent sets of subjects. In the case-control subset, 365 migraine patients [194 with aura (MA)] vs. 347 healthy controls were studied. A significant excess of the CC genotype was found in migraneurs (31.2%) as opposed to controls (20.2%; P=0.003). Using a logistic regression model corrected for sex, the CC genotype conferred a general risk for migraine twice [odds ratio (OR) 1.79, 95% confidence interval (CI) 1.27-2.53; P=0.001] higher than CT/TT genotypes. Using parents from 117 migraine families, a marginally significant trend for association could be observed (P=0.025), but the transmission disequilibrium test for alleles maternally transmitted failed to demonstrate familial association. In this subgroup, CC genotype conferred a risk for migraine over twice (OR 2.20; 95% CI 1.14-4.40; P=0.019) higher than TT/TC genotypes. In conclusion, the GNAS1 T393C variant is associated with migraine, which suggests a genetic basis for its higher SNS sensitivity.

Vaciamiento ganglionar en carcinoma escamoso transglótico / Ganglionic drainage in scaly transglotic carcinoma

Introducción: El manejo de los ganglios cervicales es fundamental en el tratamiento y pronóstico de los pacientes con carcinoma escamoso de laringe. Existe consenso en realizar vaciamiento ganglionar cervical en ausencia de adenopatías clínicas (N0) cuando el riesgo de adenopatías metastásicas ocultas supera el 20 por ciento. El carcinoma laríngeo transglótico (CTG) se caracteriza por presentar una incidencia de metástasis cervicales ocultas de 30 por ciento a 40 por ciento. Objetivo: Evaluar los hallazgos histopatológicos en los ganglios cervicales de los pacientes portadores de CTG, analizando la incidencia de metástasis ocultas y su asociación con factores de riesgo. Material y métodos: Estudio retrospectivo mediante la revisión de las fichas clínicas de pacientes portadores de CTG, sin tratamiento previo, manejados quirúrgicamente en el Hospital San Juan de Dios entre los años 1994 y 2002. Resultados: Se evaluaron 20 pacientes, 4 (20 por ciento) se presentaron con adenopatías clínicas, realizándose en 2 casos vaciamiento radical y en los 2 restantes disección funcional. Los pacientes N0 fueron 16 y se les efectuó un vaciamiento funcional bilateral. Se detectaron metástasis ocultas en 12,5 por ciento de los pacientes N0. Conclusión: Los carcinomas de ubicación transglótica N0 no se beneficiarían de un vaciamiento ganglionar cervical.

Aspirin or anticoagulants in stenosis of the middle cerebral artery: A randomized trial.

BACKGROUND: We report the results of an open, randomized, multicenter trial that compared the efficacy of aspirin to oral anticoagulants (OA) for the prevention of vascular events in patients with symptomatic stenosis of the middle cerebral artery (MCA). METHODS: Participants were randomly assigned to receive 300 mg/day of aspirin or a dose of OA (target INR 2-3). The MCA stenosis was demonstrated by conventional angiography or by at least two noninvasive examinations. Patients had either transient ischemic attack or cerebral infarct (CI) attributable to the MCA stenosis within 90 days before inclusion. The primary endpoint was: nonfatal CI, nonfatal acute myocardial infarct, vascular death and major hemorrhage. The patients were followed-up for a minimum of 1 year and a maximum of 3 years. RESULTS: The study included 28 patients (14 in each treatment group); the average age was 67 +/- 9.9 years. Men constituted 68% of the patients. After a mean follow-up of 23.1 +/- 10.9 months, there were no recurrences of CI in both groups. No endpoint was reported in the aspirin group, but 2 patients in the OA group (14.3%) exhibited vascular events: 1 acute myocardial infarct and 1 intracerebral hemorrhage). However, this difference was not statistically significant (p = 0.48). CONCLUSIONS: Our study suggests that aspirin is the treatment of choice for the prevention of vascular events in patients with symptomatic MCA stenosis.

Hemostatic markers of recanalization in patients with ischemic stroke treated with rt-PA.

OBJECTIVE: To determine whether pretreatment markers of coagulation and fibrinolysis are related to recanalization and functional outcome. METHODS: The authors included patients treated with IV rt-PA with occlusion on baseline transcranial Doppler (Thrombolysis in Brain Ischemia [TIBI] criteria) in whom recanalization within 6 hours was monitored. At baseline, the authors recorded data about demographics, vascular risk factors, the NIH Stroke Scale (NIHSS) score, early CT signs, etiology, blood glucose, and time to rt-PA. The authors also measured plasmatic markers of coagulation (fibrinogen, prothrombin fragments 1 + 2, Factor XIII, Factor VII) and fibrinolysis (alpha2-antiplasmin, Plasminogen Activator Inhibitor, Functional Thrombin Activatable Fibrinolysis Inhibitor [fTAFI]). A favorable outcome was defined as a modified Rankin score < 2 at 3 months. RESULTS: The authors studied 63 patients with a mean age of 67.3 +/- 12.5 years. The median NIHSS score was 16. Patients who recanalized had lower concentrations of alpha2-antiplasmin (87.5 +/- 18% vs 96.5 +/- 12.5%, p = 0.023) and fTAFI (91.7 +/- 26.7% vs 104.4 +/- 21%, p = 0.039). A multivariant logistic regression analysis showed that the level of alpha2-antiplasmin was the only predictive variable of recanalization (OR 0.95, 95% CI 0.91, 0.99, p = 0.038), while the NIHSS score was the only predictive variable of functional outcome (OR 0.81, 95% CI 0.72, 0.92, p = 0.001). CONCLUSION: Baseline levels of alpha2-antiplasmin were predictive of recanalization but were not related to the long-term outcome in patients treated with rt-PA within the first 3 hours.

MTHFR T677 homozygosis influences the presence of aura in migraineurs.

It has been suggested that folate metabolism could be involved in migraine pathogenesis. We analysed the 5',10'-methylenetetrahydrofolate reductase (MTHFR) genotypic distribution in a large migraine sample. We genotyped 230 migraine patients (152 migraine without aura (MO) and 78 migraine with aura (MA)) and 204 nonheadache controls. The incidence of TT homozygosis for migraine in general (12%), MO (9%) and MA (18%) did not significantly differ from that found in healthy controls (13%). Differences were significant when the frequency of TT homozygosis between MA and MO (P = 0.03, OR = 2.34, 95% CI = 1.04-5.26) was compared. There was a tendency for a higher frequency of the MTHFR T allele in the MA group (42%) as compared to MO (29%) and controls (36%). These differences were significant only in the case of MA vs. MO (P = 0.006, OR = 1.75, 95% CI = 1.15-2.65). These results could indicate that the MTHFR C677T polymorphism, causing mild hyperhomocystinaemia, might be a genetic risk factor for experiencing aura among migraineurs. Overall, however, there was no association between migraine and the C677T MTHFR polymorphism.

Fascitis necrotizante post-apendicectomía / Necrotizing fascitis post-appendectomy

La fascitis necrotizante (FN.) es una infección rápidamente progresiva que afecta a los tejidos blandos, con extensa necrosis del tejido subcutáneo y fascia subyacente, acompañada de una grave toxicidad sistémica. Puede ser secundaria a una cirugía. Dentro de las complicaciones de la apendicectomía, que es una cirugía aparentemente sencilla y frecuente, está la infección del sitio operatorio, pudiendo llegar a una FN, con las graves consecuencias que esto implica. Presentamos una serie de casos retrospectiva, correspondiente a 11 pacientes que desarrollaron esta infección posterior a una apendicectomía, entre enero del 2000 hasta mayo del 2002. Corresponden al 0,38 po ciento de los pacientes de los 2.830 operados en nuestra Institución en el mismo período. El promedio de edad fue 30 años. El tiempo que medió entre la apendicectomía y el diagnóstico de FN fue un promedio de 5,4 días. De los gérmenes aislados destaca la Escherichia Coli en 8 pacientes. El número de reintervenciones varió entre 2 y 14 veces y 2 de ellos debieron continuar con cirugías reconstructivas mayores. En 2 casos se asoció necrosis retroperitoneal, debiendo recibir tratamiento coadyuvante con oxígeno hiperbárico. La mortalidad fue de 18,2 por ciento (2 pacientes). El promedio de días de hospitalización fue de 35,5 días. De acuerdo a nuestros resultados, sugerimos que el manejo de estos pacientes debe ser multidisciplinario, resecando agresivamente el tejido necrosado, considerando que el equipo que reseca no es el mismo que debe reconstruir al paciente, logrando de esta manera una mortalidad por debajo de las publicadas hasta este momento.

Laparoscopia en la detección de lesiones ocultas de diafragma / Laparoscopy in the detection of occult diaphragm injuries

La herida de diafragma es conocida como una lesión habitualmente inadvertida en Trauma penetrante toracoabdominal. La incorporación de la laparoscopia diagnóstica en trauma, nos ha motivado recurrir a este método diagnóstico en este tipo de lesión. Se presenta una serie de 18 pacientes ingresados al Hospital de Urgencia Asistencia Pública, con diagnóstico de herida toraco-abdominal izquierda, en un período comprendido entre diciembre de 2000 a agosto 2002. En la serie, el 100 por ciento es de sexo masculino, con una edad promedio de 25,6 años. La técnica quirúrgica se estandarizó, destacando la realización del neumoperitoneo abierto y la insuflación a 10 mmHg. A todos se les realizó previamente una radiografía de tórax y a 2 una ecotomografía abdominal. La radiografía de tórax fue normal en 8 pacientes y en los otros 10 presentó alteraciones compatibles con penetración pleural. La ecotomografía abdominal mostró alteraciones inespecíficas en los 2 pacientes. Entre la agresión y la exploración transcurrió un período promedio de 20 horas. Se encontró 7 laparoscopias sin hallazgos patológicos, 7 heridas de diafragma y otras lesiones en 4. Cinco heridas de diafragma fueron suturadas por vía laparoscópica, una de ellas asistida por toracoscopia. De los 7 pacientes con herida de diafragma, 3 tenían radiografía de tórax normal. No hay complicaciones ni mortalidad atribuibles a la técnica. A pesar de lo reducido de la muestra nos parece un método seguro y confiable, considerando que el principal benefecio es detectar lesiones que habitualmente pasan inadvertidas con potencial riesgo ulterior.

Complicaciones de las fracturas de la extremidad inferior del radio / Complications of distal radius fractures

No disponible

Multielemental determination of arsenic, selenium and chromium(VI) species in water by high-performance liquid chromatography-inductively coupled plasma mass spectrometry.

A new method for the simultaneous chromatographic separation and determination of arsenite, arsenate, mono-methylarsonic acid, dimethylarsinic acid, selenite, selenate and hexavalent chromium in water is presented. Speciation was achieved by on-line coupling of anion-exchange LC and inductively coupled plasma mass spectrometry (ICP-MS). Optimisation of the chromatographic conditions led to baseline separation of the seven species in 14 min using gradient elution with NH4NO3 20 mM, pH 8.7-NH4NO3 60 mM, pH 8.7 as mobile phase. Detection limits are in the range 40-60 ng l(-1) for arsenic species, around 130 ng l(-1) for Cr(VI), and higher for Se(IV) and Se(VI) (1.2 and 1.4 microg l(-1) respectively). The method showed good accuracy and repeatability, and no interference of chloride on 75As, 77Se or 53Cr was observed. The developed method was applied to the analysis of several environmental surface water samples.

Simultaneous determination of arsenic species and chromium(VI) by high-performance liquid chromatography-inductively coupled plasma-mass spectrometry.

The simultaneous determination of As(III), As(V), monomethylarsenic acid (MMA), dimethylarsinic acid (DMA) and Cr(VI) in fresh water has been carried out by coupling an anion-exchange column to an inductively coupled plasma-mass spectrometer. Optimisation of chromatographic conditions led to baseline separation of signals from the five species in approximately 9 min using gradient elution. Detection limits were 0.02-0.05 microg As l(-1) and 5.5 microg Cr l(-1). Repeatability was 2-3% for arsenic species and higher, i.e., 8%, for Cr(VI) due to the higher background for this species. Arsenic species and hexavalent chromium stability in surface water samples was evaluated, and storage conditions were set to 1 day at 4 degrees C in polyethylene flasks (without acidification) in order to avoid As(III)-As(V) conversions. The method was applied to the analysis of surface water.

Differential sensitivity of mouse strains to platelet activating factor-induced vasopermeability and mortality: effect of antagonists.

In the present study, we have compared the responses to platelet-activating factor (PAF) of A/J and BALB/c inbred mouse strains. Two PAF-induced events were analyzed: increased vasopermeability, measured by extravasation of Evans blue dye (EB), and mortality. PAF injected into the peritoneal cavity induced a bell-shaped dose-response curve of EB extravasation in both strains of mouse. In A/J mice, maximal EB extravasation was reached with 0.1 microgram of PAF/mouse, whereas in BALB/c mice maximal extravasation was attained at a 10-fold greater PAF concentration. PAF-induced mortality also differed among these mouse strains; the LD50 was 12.1 micrograms/kg in A/J and 21.2 micrograms/kg in BALB/c mice. Thus, these strains differ significantly regarding both events mediated by PAF. Surprisingly, the F1 hybrid (A/J x BALB/c) mice were as sensitive as the A/J strain to PAF-induced extravasation but were as resistant as the BALB/c mice to PAF-induced mortality. The effects of the PAF antagonists BN 52021 and WEB 2086 were compared in the F1 hybrids. It was found that 1.0 mg/kg of WEB 2086 affected PAF-induced extravasation at almost all PAF doses tested (0.03-3.0 micrograms) while 15 mg/kg of BN 52021 was only effective at doses of PAF below 0.3 microgram. Both antagonists prevented PAF-induced mortality. Our results indicate that the two events induced by PAF may be controlled by different genes.