RESUMO
31P magnetic resonance spectroscopy (31P MRS) and biochemical analysis of extracts were applied to study the metabolic response to X-irradiation of small cell lung cancer in nude mice. Two small cell lung cancer xenografts, CPH SCCL 54A and 54B, with different radiosensitivity, although derived from the same patient, were studied. A total of 126 individual tumors were examined. Following 5.0-Gy irradiation, a reversible increase in the ATP/Pi ratio, reaching twice the pretreatment level within 2 wk, was observed with 31P MRS, while 20 Gy induced a reversible decrease in the ATP/Pi ratio. The t1/2 of this decline was 2 to 3 h for 54A and about 6 h for the less radiosensitive 54B. The 31P MRS data were compared with biochemical analysis of tumors freeze-clamped and extracted at similar intervals after 20 Gy. It appeared that an acute reversible increase in Pi concentration was the major cause of the ATP/Pi decrease induced by 20 Gy. A linear correlation between ATP/Pi estimated by 31P MRS and by analytical biochemistry was found. The ATP/Pi ratio may be valuable for early assessment of radiosensitivity of small cell lung cancer tumors.
Assuntos
Carcinoma de Células Pequenas/radioterapia , Neoplasias Pulmonares/radioterapia , Trifosfato de Adenosina/metabolismo , Animais , Carcinoma de Células Pequenas/metabolismo , Linhagem Celular , Humanos , Neoplasias Pulmonares/metabolismo , Imageamento por Ressonância Magnética , Camundongos , Camundongos Nus , Transplante de Neoplasias , Fosfatos/metabolismo , Fósforo , Transplante HeterólogoRESUMO
We have addressed the question of whether the Na/K+-ATPase in the human erythrocyte is in a state of near-equilibrium by varying the extracellular ratio of Na+ and K+ and following the cytosolic phosphorylation potential by 31P-NMR and by combined enzymatic colorimetric measurements. There was no correlation at room temperature between the extracellular Na+/K+ ratio and the cytosolic phosphorylation potential measured either by NMR or alternative methods. The cytosolic phosphorylation potential measured by NMR was 4100 +/- 1300 (S.E.) M-1 at an extracellular K+ concentration of 5.9 mM (Na+/K+ ratio of 24.3) and 2800 +/- 700 (S.E.) M-1 at 75 mM extracellular K+ (Na+/K+ ratio of 0.99). The chemically determined phosphorylation potential was 6400 +/- 1200 (S.E.) and 5000 +/- 700 (S.E.) M-1 at 5.9 and 75 mM extracellular K+, respectively. Omission of Ca2+ from the buffer solutions did not affect the results. A consistent finding in this study was that the NMR-determined value of ATP was about 10-20% lower than the value determined enzymatically on perchloric acid extracts. The inorganic phosphate (Pi) was fully NMR visible.
Assuntos
Eritrócitos/enzimologia , Espectroscopia de Ressonância Magnética , ATPase Trocadora de Sódio-Potássio/sangue , Calibragem , Espaço Extracelular/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Fósforo , Fosforilação , Potássio/metabolismo , Potenciometria , Sódio/metabolismoRESUMO
The purpose of this study was to investigate the influence of structure and composition of microemulsions (Labrasol/Plurol Isostearique/isostearylic isostearate/water) on their transdermal delivery potential of a lipophilic (lidocaine) and a hydrophilic model drug (prilocaine hydrochloride), and to compare the drug delivery potential of microemulsions to conventional vehicles. Self-diffusion coefficients determined by pulsed-gradient spin-echo NMR spectroscopy and T(1) relaxation times were used to characterise the microemulsions. Transdermal flux of lidocaine and prilocaine hydrochloride through rat skin was determined in vitro using Franz-type diffusion cells. The formulation constituents enabled a broad variety of microemulsion compositions, which ranged from water-continuous to oil-continuous aggregates over possible bicontinuous structures, with excellent solubility properties for both lipophilic and hydrophilic compounds. The microemulsions increased transdermal flux of lidocaine up to four times compared to a conventional oil-in-water emulsion, and that of prilocaine hydrochloride almost 10 times compared to a hydrogel. A correlation between self-diffusion of the drugs in the vehicles and transdermal flux was indicated. The increased transdermal drug delivery from microemulsion formulations was found to be due mainly to the increased solubility of drugs and appeared to be dependent on the drug mobility in the individual vehicle. The microemulsions did not perturb the skin barrier, indicating a low skin irritancy.
Assuntos
Emulsões , Pele/metabolismo , Administração Cutânea , Animais , Difusão , Irritantes/toxicidade , Lidocaína/administração & dosagem , Lidocaína/química , Espectroscopia de Ressonância Magnética , Masculino , Veículos Farmacêuticos , Prilocaína/administração & dosagem , Prilocaína/química , Ratos , Ratos Wistar , Pele/efeitos dos fármacos , SolubilidadeRESUMO
The hydrolysis of cyanogen chloride (ClCN) was studied as a function of temperature and pH. Results were used to resolve discrepancies among previously reported kinetic constants. The pH dependence was studied over a range of 9.54-10.93 at a temperature of 21.0 degrees C. The effect of temperature was investigated over the range of 10-30 degrees C at a pH of approximately 10. Changes in the concentrations of ClCN and the reaction products cyanic acid and chloride ion were monitored with time. For the conditions corresponding to these experiments, the hydroxide-assisted hydrolysis pathway predominated. Collision frequency factor and activation energies recommended to represent the hydrolysis of ClCN in aqueous solution are A = 2.06 x 10(11) M-1 s-1 and Ea = 60,980 J mol-1 for the hydroxide-ion-assisted reaction, and A = 9.97 x 10(8) s-1 and Ea = 87,180 J mol-1 for the water-assisted reaction.
Assuntos
Cianetos/metabolismo , Hidróxidos/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Modelos Químicos , Soluções , TemperaturaRESUMO
This study presents Norwegian doctors' attitudes concerning co-operation with homeopaths, their advice to patients who want to try homeopathic treatment and for which diseases, if any, they might be positive to homeopathic treatment. The Norwegian Medical Association made a randomised, stratified sample consisting of 2,019 Norwegian doctors below the age of 71. The study was made questionnaire-based and a total of 1,434 doctors (71%) replied. 7% of the doctors have or wish to have patient-associated collaboration with homeopaths. 32% would give positive advice to patients who expressed a desire to try homeopathic treatment, while 50%, owing to insufficient knowledge, would not give advice. Doctors educated abroad are more positive to homeopathic treatment than doctors educated in Norway are. 50% of Norwegian doctors tend to be positive to homeopathic treatment for one or more specific conditions. Anxiety, migraine and hayfever are the conditions most often mentioned. Male senior doctors are the least positive to homeopathic treatment for all of the listed conditions. Patients who would like to try homeopathic treatment after consultation with a doctor should consult a female general practitioner who has studied abroad.
Assuntos
Atitude do Pessoal de Saúde , Homeopatia , Médicos/psicologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Encaminhamento e Consulta , Inquéritos e QuestionáriosRESUMO
UNLABELLED: BACKGROUND/AIM OF THE STUDY: During the past 50 years, a decrease in incidence of appendicitis has been reported. The various studies were retrospective and based on different data sources. In the present study, we analyze prospectively the incidence of acute appendicitis during a 10-year period in a well defined population of 265,000. METHODS: Prospective registration of all operations performed in patients with suspected acute appendicitis in the catchment area of a single institution. The diagnosis of acute appendicitis was based on histology in all cases. The annual incidence of acute appendicitis was calculated with regard to nonperforated and perforated acute appendicitis. MAIN RESULTS: Between 1989 and 1998, 2,861 patients underwent surgery for suspected acute appendicitis. In 2,232 (78%) patients, acute appendicitis was confirmed histologically. Mean annual incidence was 84/100,000 (95% confidence interval 80 to 88/100,000). Crude incidence remained stable during the study period, with the exception of a significant increase in 1991 followed by a significant decrease the next year. Nonperforated acute appendicitis showed a different incidence pattern as compared to perforated acute appendicitis. CONCLUSION: In our prospective study, the incidence of acute appendicitis remained stable in our well-defined study population during the study period of 10 years. This is in contrast to the majority of studies during the last decades.
Assuntos
Apendicite/diagnóstico , Apendicite/epidemiologia , Doença Aguda , Adolescente , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Apendicectomia/estatística & dados numéricos , Apendicite/cirurgia , Criança , Pré-Escolar , Intervalos de Confiança , Feminino , Humanos , Incidência , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Noruega/epidemiologia , Probabilidade , Estudos Prospectivos , Fatores de Risco , Distribuição por SexoRESUMO
BACKGROUND: Although stimulation of certain acupressure points for long has been claimed to alleviate nausea, previous research has left contradictory results. The aim of our study was to find out if acupressure can alleviate nausea and vomiting in early pregnancy. MATERIAL AND METHODS: 97 women with mean gestational length between 8 and 12 weeks were randomized to use either active acupressure or placebo acupressure bands. Symptoms were recorded before they entered the study, during the use of the wristbands, and after the end of the study, according to the intensity, duration and nature of complaints. RESULTS: 71% of the women in the intervention group reported both less intensive morning sickness and shorter duration of symptoms. The same tendency was seen in the placebo group, with 59% reporting less intensity and 63% shorter duration of symptoms, However, significance levels of 5% were reached regarding duration of symptoms, which was reduced by 2.74 hours in the intervention group compared to 0.85 hours in the placebo group (p = 0.0018). INTERPRETATION: Acupressure wristband might be an alternative for morning sickness in early pregnancy, especially before pharmaceutical treatment is considered.
Assuntos
Acupressão , Náusea/terapia , Complicações na Gravidez/terapia , Vômito/terapia , Acupressão/métodos , Feminino , Humanos , GravidezRESUMO
Several circumstances may explain the great variation in reported proton T1 and T2 relaxation times usually seen. This study was designed to evaluate the accuracy of relaxation time measurements by magnetic resonance imaging (MRI) operating at 1.5 tesla. Using a phantom of nine boxes with different concentrations of CuSO4 and correlating the calculated T1 and T2 values with reference values obtained by two spectrometers (corrected to MRI-proton frequency = 64 MHz) we found a maximum deviation of about 10 per cent. Measurements performed on a large water phantom in order to evaluate the homogeneity in the imaging plane showed a variation of less than 10 per cent within 10 cm from the centre of the magnet in all three imaging planes. Changing the gradient field strength apparently had no influence on the T2 values recorded. Consequently diffusion processes seem without significance. It is concluded that proton T1 and T2 relaxation times covering the majority of the biologic range can be measured by MRI with an overall accuracy of 5 to 10 per cent. Quality control studies along the lines indicated in this study are recommended.
Assuntos
Espectroscopia de Ressonância Magnética/métodos , Modelos Estruturais , Controle de Qualidade , Fatores de TempoRESUMO
OBJECTIVE: To find out whether acupressure wristband can alleviate nausea and vomiting in early pregnancy. DESIGN: Double-blind, placebo-controlled study. SUBJECTS: 97 women with mean gestational length completed 8-12 weeks. MAIN OUTCOME MEASURES: Symptoms were recorded according to intensity, duration and nature of complaints. RESULTS: 71% of women in the intervention group reported both less intensive morning sickness and reduced duration of symptoms. The same tendency was seen in the placebo group, with 59% reporting less intensity and 63% shorter duration of symptoms. However, a significance level of 5% was reached only in the case of duration of symptoms, which was reduced by 2.74 hours in the intervention group compared to 0.85 hours in the placebo group (p = 0.018). CONCLUSIONS: Acupressure wristband might be an alternative therapy for morning sickness in early pregnancy, especially before pharmaceutical treatment is considered.
Assuntos
Acupressão/métodos , Náusea/terapia , Complicações na Gravidez/terapia , Acupressão/instrumentação , Adulto , Assistência Ambulatorial/métodos , Método Duplo-Cego , Feminino , Humanos , Noruega , Placebos , Gravidez , Autoavaliação (Psicologia) , População Urbana , Punho/fisiologiaRESUMO
The mycotoxin fusarochromanone, a metabolite of Fusarium fungi, is able to induce tibial dyschondroplasia (TD) in chickens under experimental conditions. On the basis of health surveillance data on TD, two broiler farms with TD prevalence rates of up to 56% were identified. In the corresponding pelleted feed samples, fusarochromanone was detected in all 12 samples analyzed by column purification and TLC, with concentrations 4 to 59 micrograms/kg. No Fusarium fungi were available from the feed because of the pelleting process, but seven Fusarium equiseti strains previously isolated from Danish cereals were checked for fusarochromanone production, and all produced fusarochromanone at 57 to 1,435 mg/kg. Thus, the potential for fusarochromanone production by F. equiseti is considerable. The identification of fusarochromanone from feed and F. equiseti was confirmed by mass, infrared, and nuclear magnetic resonance spectral analyses. This is the first report of fusarochromanone as a naturally occurring contaminant.