RESUMEN
BACKGROUND: The Russian invasion of Ukraine has driven millions of Ukrainians away from their homes. Among these, the majority have likely experienced war-related potentially traumatic events, and some will experience symptoms of posttraumatic stress disorder (PTSD). The aims of the study are to estimate the prevalence of PTSD and Complex PTSD (CPTSD) in displaced Ukrainians and examine associations between war- and other potentially traumatic exposures and (C)PTSD. METHODS: Questionnaires were distributed to all registered adult Ukrainians (18+) who arrived in Denmark between February 24th 2022 and February 15th 2023 (N = 18,389). We estimate the prevalence of war exposures, other potentially traumatic exposures, and (C)PTSD. In logistic regression analyses, we test if exposure to war and other potentially traumatic events are associated with PTSD and CPTSD. RESULTS: The final sample size was 6993 (38.0 %). Responders were more likely to be female and younger than non-responders. Prevalence of PTSD and CPTSD was 15.9 % and 13.5 %, respectively. Female gender, high education, and loss of a relative due to the war were associated with (C)PTSD. Direct and indirect exposure to war and combat was related to PTSD but not CPTSD, while exposure to war prior to the 2022 invasion was related to CPTSD but not PTSD. LIMITATIONS: The study is cross-sectional and based on self-report. CONCLUSION: Close to one third of the sample fulfill the criteria of PTSD or CPTSD. War exposures are differentially related to PTSD and CPTSD. The findings illustrate that trauma-related psychopathology is a pertinent problem in displaced Ukrainians.
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Refugiados , Trastornos por Estrés Postraumático , Humanos , Trastornos por Estrés Postraumático/epidemiología , Femenino , Ucrania/epidemiología , Masculino , Adulto , Refugiados/estadística & datos numéricos , Refugiados/psicología , Prevalencia , Dinamarca/epidemiología , Persona de Mediana Edad , Adulto Joven , Encuestas y Cuestionarios , Adolescente , Estudios de Cohortes , Anciano , Estudios TransversalesRESUMEN
The habenula is an epithalamic structure through which descending connections pass from the telencephalon to the brainstem, putting it in a key location to provide feedback control over the brainstem monoaminergic projections ascending to the telencephalon. Habenular nuclei lesions have been shown to impair memory function. The habenular nuclei have high concentrations of nicotinic receptors. In this study we assessed the role of habenular nicotinic receptors for working memory. Adult female Sprague-Dawley rats were trained on a 16-arm maze to assess spatial working and reference memory. All rats had at least 18 sessions of training and then had bilateral chronic infusion cannulae placed into the lateral habenula nucleus. These cannulae were each connected to a slow delivery osmotic minipump that chronically infused mecamylamine 100 microg/side/day (n=9) or vehicle (aCSF) for controls (n=15) for a period of 4 weeks. Both mecamylamine-infused and control rats were acutely injected (s.c.) with nicotine (0, 0.2 or 0.4 mg/kg) in a repeated measures counterbalanced design twice at each dose during the chronic local infusion period. There was a significant (P<0.025) mecamylaminexnicotine interaction effect on memory performance. Without nicotine injection the chronic habenular mecamylamine infusion caused a significant (P<0.05) increase in total memory errors. The 0.4 mg/kg nicotine dose significantly (P<0.005) reversed the mecamylamine-induced memory impairment, returning performance back to levels seen in rats with control aCSF habenular infusions. The current study determined that nicotinic receptors in the lateral habenular nucleus are important for spatial memory function. Descending projections from the telencephalon through the habenula to brainstem nuclei using nicotinic receptors appear to be a key pathway for memory processing.
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Habénula/metabolismo , Aprendizaje por Laberinto/efectos de los fármacos , Memoria a Corto Plazo/fisiología , Receptores Nicotínicos/metabolismo , Conducta Espacial/fisiología , Análisis de Varianza , Animales , Conducta de Elección/efectos de los fármacos , Conducta de Elección/fisiología , Relación Dosis-Respuesta a Droga , Femenino , Habénula/efectos de los fármacos , Aprendizaje por Laberinto/fisiología , Mecamilamina/farmacología , Memoria a Corto Plazo/efectos de los fármacos , Nicotina/farmacología , Agonistas Nicotínicos/farmacología , Antagonistas Nicotínicos/farmacología , Desempeño Psicomotor/efectos de los fármacos , Desempeño Psicomotor/fisiología , Ratas , Ratas Sprague-Dawley , Conducta Espacial/efectos de los fármacosRESUMEN
Fibrin sealants have been proposed as depot matrices for substances due to their biocompatibility, advantageous biological properties, and widespread use in wound healing. This study showed possibilities for a continuous and controlled release of pharmaceutically active substances out of a fibrin matrix. Substances of interest were linked to naturally occuring fibrin-anchors, (i) thrombin, (ii) fibronectin, and (iii) DNA. Fibronectin and thrombin bind fibrin by a specific binding moiety and DNA by charge. Fibrin clots were prepared from Tisseel Fibrin Sealant (Baxter AG, Vienna) by mixing 100 mg/ml fibrinogen, the substance of interest, and 4 U/ml of thrombin. Chemical crosslinking of proteins was performed with EDC using standard reaction conditions. Modification of proteins with biotin and PPACK was performed with N-hydroxysuccinimid activated compounds. With fibrin-anchors pharmaceutically active substances, i.e., tumor necrosis factor (TNF), albumin, and plasmid-DNA, were continously released over 10 days. In conclusion, the naturally occuring proteins fibronectin and thrombin with a fibrin binding moiety or DNA can be used as fibrin-anchors.
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ADN/administración & dosificación , Preparaciones de Acción Retardada/química , Fibrina/química , Preparaciones Farmacéuticas/administración & dosificación , Clorometilcetonas de Aminoácidos/química , Animales , Anticuerpos/química , Anticuerpos/inmunología , Disponibilidad Biológica , Bovinos , Citocromos c/administración & dosificación , Citocromos c/farmacocinética , ADN/química , ADN/farmacocinética , Preparaciones de Acción Retardada/síntesis química , Fibrinógeno/química , Fibronectinas/química , Preparaciones Farmacéuticas/química , Plásmidos/administración & dosificación , Plásmidos/química , Plásmidos/farmacocinética , Albúmina Sérica/administración & dosificación , Albúmina Sérica/química , Albúmina Sérica/farmacocinética , Estreptavidina/administración & dosificación , Estreptavidina/química , Estreptavidina/farmacocinética , Trombina/química , Factor de Necrosis Tumoral alfa/administración & dosificación , Factor de Necrosis Tumoral alfa/inmunología , Factor de Necrosis Tumoral alfa/farmacocinética , Activador de Plasminógeno de Tipo Uroquinasa/química , beta-Galactosidasa/administración & dosificación , beta-Galactosidasa/farmacocinéticaRESUMEN
BACKGROUND: The diversity of the nation is one of society's greatest assets, but this feature is overshadowed by the disproportionate burden of disease that exists among America's minorities. Evidence of the disparate health status has been documented in low life expectancy, cancer, diabetes, cardiovascular, and kidney disease as well as a plethora of disorders that necessitate organ transplantation. Many minorities have been reluctant to register to become organ donors. This circumstance can be alleviated by educating the public regarding the necessity of organ transplantation. We have developed a "unique" collaborative outreach program designed to promote acceptance of organ donation in African-Americans (AAs). Our outreach curriculum at Bureau of Motor Vehicles (BMV) has resulted in increased registrations and awareness regarding the need and positive perceptions toward donation. METHODS: We developed a culturally sensitive outreach program: cultural sensitivity indicates how culture has the ability to influence communication between patients and health providers. An "Outreach Promotional Contest" was strategically targeted toward 28 Ohio BMVs to promote and assist in an outreach educational program regarding organ donation/registry. RESULTS: The consequence/results has been an increase of 3.4% in the BMV locations. The one BMV, with the highest increase was attended predominantly by AAs which moreover, won first place in the contest (6.425%; P < .05). CONCLUSION: To increase the number of people willing to register, we believe that both community education regarding the need and importance, as well as culturally sensitive promotion of organ donation, is the best way to increase organ donor registries particularly among minority populations.
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Población Negra/estadística & datos numéricos , Donantes de Tejidos/estadística & datos numéricos , Obtención de Tejidos y Órganos/estadística & datos numéricos , Cadáver , Humanos , Vehículos a Motor/estadística & datos numéricos , OhioRESUMEN
Launching the Tidal Model: evaluating the evidence This paper reports on two evaluations of the Tidal Model, in the context of two separate acute admission wards, one in Birmingham (2004) and the other in Newcastle (2001), and makes recommendations concerning the criteria and type of reasoning appropriate to evaluating the evidence the two projects have generated. In the Birmingham study, results showed that in the year following the introduction of the Tidal Model, the total number of serious untoward incidents such as physical assault, violence and harassment, decreased by 57%. Nurse satisfaction with their work also improved with nurses rating the model superior to their previous way of working. Inpatient service user assessment of the overall quality of their care was also positive. These findings are then compared with the positive results of an earlier study of the Tidal Model undertaken in Newcastle in 2001. That study was criticized, however, for not showing conclusively that the positive results of the evaluation correlated with the introduction of the Tidal Model. This criticism is briefly examined in the light of both ancient (Aristotle) and modern (Charles Peirce) understandings of the nature of evidence and suggests that such criticism begs the question of the nature of proof. The paper concludes by arguing that, according to both Aristotle and the procedures of abductive reasoning advocated by Charles Peirce, inferring a positive correlation between the results of both studies and the introduction of Tidal Model is a good example of reasonable inference to the best explanation. The available evidence suggests that the results of both studies render the conclusion probable and thus 'good enough' to warrant serious consideration for implementing the Tidal Model more widely within and across Mental Health NHS Trusts.
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Satisfacción en el Trabajo , Enfermeras y Enfermeros/psicología , Desarrollo de Programa , Enfermería Psiquiátrica/métodos , Humanos , Trastornos Mentales/enfermería , Evaluación de Programas y Proyectos de Salud , Violencia/estadística & datos numéricosRESUMEN
Characterizing how chemical compounds bind to human serum albumin (HSA) is essential in evaluating drug candidates. Using warfarin as a test system, we validate the application of BIACORE SPR biosensors to reliably determine binding constants for drug/HSA interactions. The binding responses for warfarin over HSA surfaces were extremely reproducible even though warfarin is small compared to the size of the immobilized protein. At high concentrations, warfarin bound at more than one site on HSA, which is consistent with its known binding properties. The affinity we determined for the high-affinity site (K(25 degrees C)(d) = 3.7 +/- 1.2 microM), as well as the dissociation rate constant (k(25 degrees C)(d) = 1.2 s(-1)), are also consistent with binding constants determined previously. These results validate the biosensor technology and illustrate how BIACORE can be used to study drug/HSA interactions in a high-resolution mode. Using a set of 10 test compounds, we present a protocol for determining equilibrium dissociation constants for HSA in a high-throughput mode. Our method involves working at low compound concentrations and fitting the equilibrium data for all compounds simultaneously. We show that the % bound values determined by SPR correlate with the values determined by solution-based methods. The ability to examine directly the binding of small molecules (130-800 Da), coupled with minimal sample requirements and automated instrumentation, makes BIACORE technology applicable for evaluating drug/HSA interactions.
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Albúmina Sérica/metabolismo , Resonancia por Plasmón de Superficie/métodos , Warfarina/metabolismo , Sitios de Unión , Dimetilsulfóxido/química , Humanos , Reproducibilidad de los Resultados , Temperatura , Factores de TiempoRESUMEN
A series of biodistribution studies were conducted with the radiotracer, [(18)F]N-(4'-fluorobenzyl)-4-(3-bromophenyl)acetamide, [(18)F]1 in nude mice bearing tumor xenografts of the mouse mammary adenocarcinoma, line 66. This radiotracer has a high affinity for both sigma(1) and sigma(2) receptors. In vivo studies were also conducted in order to assess the effect of blocking sigma(1) receptors on tumor uptake and the tumor:background ratio of this radiotracer. The results of these studies revealed that blocking the sigma(1) receptor so that only the sigma(2) receptors are labeled in vivo, results in a higher tumor:background ratio with only a small reduction in the tumor uptake of the radiotracer relative to the no-carrier-added (i.e., nonselective) conditions. Comparative in vivo studies were also conducted with the anatomic and metabolic imaging agent, [(18)F]FDG, and a radiolabeled DNA precursor, [(125)I]IUdR. Both of these radiolabeled compounds represent classes of agents that have been proposed for imaging the proliferative status of solid tumors. The results of these studies indicated that a sigma(2)-selective imaging agent may be, 1) a better anatomic imaging agent for breast cancer than [(18)F]FDG, and 2) a better functional imaging agent than the radiolabeled DNA precursors, [(123/124)I]IUdR and [(11)C]thymidine, for measuring the proliferative status of breast tumors with PET and SPECT. However, additional studies will be needed to compare sigma(2)-selective imaging agents with [(18)F]FLT in order to determine which is the more appropriate imaging agent for measuring the proliferative status of breast tumors with PET.
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Acetamidas/síntesis química , Neoplasias/diagnóstico por imagen , Radiofármacos , Receptores sigma/metabolismo , Adenocarcinoma/diagnóstico por imagen , Animales , Femenino , Fluorodesoxiglucosa F18 , Idoxuridina , Neoplasias Mamarias Experimentales/diagnóstico por imagen , Ratones , Ratones Desnudos , Neoplasias/metabolismo , Cintigrafía , Receptores sigma/antagonistas & inhibidores , Distribución TisularRESUMEN
The oral cavity is exposed to a variety of environmental insults. Salivary secretions play a critical role in maintaining oral health via innate host defense mechanisms and secretion of secretory IgA. Human beta-defensins (hBD) are antimicrobial peptides that are a component of the innate immune response; they are expressed in epithelia and are proposed to have a role in mucosal defense. hBD-1 mRNA is constitutively expressed in numerous mucosal tissues, including human gingiva and submandibular and parotid glands. Our objective was to detect the expression and localization of hBD-1 peptide in human salivary glands and in saliva. Minor salivary gland tissue was obtained from biopsies of patients with mucoceles (n = 20). hBD-1 peptide was detected by immunohistochemistry; expression was localized to the ductal cells and not the acinar cells of these glands. The peptide was located apically, toward the lumen in the duct cells. Further evaluation showed stronger hBD-1 expression in ducts with periductal inflammation, as indicated by the immunostaining of serial sections with anti-CD45 specific for B- and T-lymphocytes. Statistical analysis showed a strong correlation of hBD-1 staining and inflammation. Results of immunolocalization suggest that hBD-1 functions to protect salivary glands from retrograde infection, that expression of the peptide is enhanced in inflamed sites, and that post-transcriptional regulatory mechanisms may be involved in hBD-1 peptide expression. Western immunoblot analysis also detected hBD-1 peptide in unstimulated, whole, acidified saliva from normal volunteers. However, hBD-1 peptide associated with salivary mucin resulted in loss of the detection in a dot-immunoblot assay. Association of hBD-1 with salivary mucin may facilitate peptide distribution and adherence to oral surfaces and aid its function within the oral cavity.
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Regulación de la Expresión Génica/fisiología , Proteínas/metabolismo , Saliva/metabolismo , Conductos Salivales/metabolismo , Glándulas Salivales Menores/metabolismo , beta-Defensinas , Adulto , Biopsia , Western Blotting/métodos , Defensinas , Humanos , Immunoblotting/métodos , Inmunohistoquímica , Mucocele/metabolismo , Mucocele/patología , Proteínas/análisis , Saliva/química , Conductos Salivales/química , Conductos Salivales/patología , Enfermedades de las Glándulas Salivales/metabolismo , Enfermedades de las Glándulas Salivales/patología , Glándulas Salivales Menores/química , Glándulas Salivales Menores/patología , Sialadenitis/metabolismo , Sialadenitis/patologíaRESUMEN
The need for tracheal intubation in the emergency department is often unpredictable and precipitous in nature. When compared with the operating room, a higher incidence of difficult intubation is observed. There are currently no accepted guidelines with respect to the stocking of difficult airway equipment in the emergency department. We have conducted a telephone survey to determine the availability of equipment for the management of the difficult airway in English emergency departments. Overall, the majority of units held a curved laryngoscope blade (100%), gum elastic bougie (99%) and surgical airway device (98%). Of alternative devices for ventilation, a laryngeal mask airway was kept by 65% of departments, a needle cricothyroidostomy kit by 63% and an oesophageal-tracheal twin-lumen airway (Combitube) by 18%. Of alternative devices for intubation, fewer than 10% held a retrograde intubating kit, intubating laryngeal mask, bronchoscope or lighted stylet. Seventy-four per cent of departments held an end-tidal carbon dioxide detector.
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Servicio de Urgencia en Hospital , Intubación Intratraqueal/instrumentación , Obstrucción de las Vías Aéreas/terapia , Capnografía/instrumentación , Inglaterra , Encuestas de Atención de la Salud , Humanos , Máscaras Laríngeas , LaringoscopiosRESUMEN
(+)-1'-[4-Hydroxy-1-(4-fluorobenzyl)piperidin-3-yl]spiro[1H- indene-1,4'- piperidine] {(+)-Spiro-FBT}, a high-affinity vesicular acetylcholine transporter ligand, was labeled with fluorine-18, and evaluated in the rat and monkey. In the rat brain, (+)-[18F]Spiro-FBT accumulated preferentially in the striatum, hippocampus, and cortex, brains regions containing high-to-moderate densities of cholinergic terminals. However, due to rapid metabolism, no preferential accumulation of the radiotracer was observed in corresponding regions of the monkey brain. Consequently, rapid metabolism renders (+)-[18F]Spiro-FBT unsuitable for studying cholinergic function with positron emission tomography.
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Acetilcolina , Proteínas Portadoras/metabolismo , Proteínas de Transporte de Membrana , Piperidinas/síntesis química , Compuestos de Espiro/síntesis química , Vesículas Sinápticas , Proteínas de Transporte Vesicular , Animales , Encéfalo/metabolismo , Estudios de Evaluación como Asunto , Radioisótopos de Flúor , Macaca mulatta , Masculino , Estructura Molecular , Piperidinas/farmacocinética , Ensayo de Unión Radioligante , Ratas , Ratas Sprague-Dawley , Compuestos de Espiro/farmacocinética , Distribución Tisular , Tomografía Computarizada de Emisión , Proteínas de Transporte Vesicular de AcetilcolinaRESUMEN
Spring wheat (Triticum aestivum L., cv. Yecora Rojo) was grown in the intensive agricultural biome (IAB) of Biosphere 2 during the l995-l996 winter/spring season. Environmental conditions were characterized by a day/night temperature regime of 27/17 degrees C, relative humidity (RH) levels around 45%, mean atmospheric CO2 concentration of 450 ppmv, and natural light conditions with mean intensities about half of outside levels. Weekly samples of above-ground plant matter were collected throughout the growing season and phenological events recorded. A computer model, CERES-Wheat, previously tested under both field and controlled conditions, was used to simulate the observed crop growth and to help in data analysis. We found that CERES-Wheat simulated the data collected at Biosphere 2 to within 10% of observed, thus suggesting that wheat growth inside the IAB was comparable to that documented in other environments. The model predicts phenological stages and final dry matter (DM) production within l0% of the observed data. Measured DM production rates, normalized for light absorbed by the crop. suggested photosynthetic efficiencies intermediate between those observed under optimal field conditions and those recorded in NASA-Controlled Ecological Life-Support Systems (CELSS). We suggest that such a difference can be explained primarily in terms of low light levels inside the IAB, with additional effects due to elevated CO2 concentrations and diffuse light fractions.
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Biomasa , Dióxido de Carbono/farmacología , Sistemas Ecológicos Cerrados , Sistemas de Manutención de la Vida , Modelos Biológicos , Triticum/crecimiento & desarrollo , Agricultura , Simulación por Computador , Ambiente Controlado , Luz , Valor Predictivo de las Pruebas , Temperatura , Triticum/efectos de los fármacosRESUMEN
OBJECTIVE: To test the hypothesis that increasing the intake of isoflavones by dietary supplementation may produce a therapeutic effect in reducing the incidence and severity of hot flushes in menopausal women. METHODS: Fifty-one postmenopausal women were randomized to placebo and active (one tablet per day of a 40-mg isoflavone supplement) groups in a cross-over design trial. After a 1-week run-in period, subjects were commenced on a 12-week period of treatment (active or placebo), followed by a 1-month placebo wash-out period, then crossed over to the alternative treatment regimen for a further 14 weeks. Symptom diaries were maintained throughout the trial and at the start and end of treatment. Plasma sex hormone binding globulin (SHBG) assay, full blood count, biochemical profiles, vaginal swabs and vaginal ultrasound scans were performed and isoflavones determined in 24-h urine collections by high-pressure liquid chromatography (HPLC) analysis. RESULTS: There was no significant difference between active and placebo groups in the reduction in hot flushes between start and finish time-points. Analysis performed on interim data time-points revealed a substantially greater reduction in flushing in the active group than placebo at 4 and 8 weeks after commencement of treatment, but this was not statistically significant. There were no significant differences between groups for Greene scores or in SHBG levels, hematological or biochemical parameters and vaginal swab or ultrasound findings. The combined values for all subjects, regardless of treatment group, revealed a strong negative correlation between the level of urinary isoflavone excretion and the incidence of hot flushes. CONCLUSIONS: These data do not indicate a therapeutic benefit from dietary supplementation with isoflavones in women experiencing menopausal symptoms, but do indicate that the apparent placebo effect in many studies of menopausal symptoms may be attributable to dietary sources of isoflavones. The study also demonstrates that 3 months of isoflavone supplementation did not cause adverse events or endometrial changes.
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Isoflavonas/administración & dosificación , Menopausia , Cromatografía Líquida de Alta Presión , Estudios Cruzados , Suplementos Dietéticos , Femenino , Genisteína/orina , Sofocos/epidemiología , Humanos , Isoflavonas/orina , Persona de Mediana Edad , Placebos , Extractos Vegetales/administración & dosificación , Globulina de Unión a Hormona Sexual/análisis , Ultrasonografía , Vagina/química , Vagina/diagnóstico por imagenRESUMEN
Previous research has suggested that a noncontrolling, independence-encouraging parenting style is correlated with children's having an internal locus of control. In the present study, children's and adolescents' reports of parent behaviors were used. Parental acceptance and child-centeredness were found to be related to more internal control beliefs in both preadolescent children and adolescents. Parental controlling behavior, however, was related to more internal control beliefs in preadolescent children and more external control beliefs in adolescents. The relationships among structure, parent controlling behavior, and the age and developmental level of children are discussed.
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Actitud , Control Interno-Externo , Responsabilidad Parental/psicología , Desarrollo de la Personalidad , Adolescente , Niño , Femenino , Humanos , Individualismo , MasculinoRESUMEN
The mammalian pulmonary toxin 4-ipomeanol (IPO) is activated by the cytochrome P450 system in bronchial Clara cells in animals. The resulting metabolites bind rapidly to macromolecules, producing localized cytotoxicity. IPO has in vitro and in vivo antitumor activity in non-small cell lung cancer (NSCLC) and thus was proposed as a lung cancer-specific antitumor agent. We have completed a directed Phase I trial in patients with NSCLC. Forty-four patients (34 men and 10 women) with NSCLC were treated with IPO. All but two patients had an Eastern Cooperative Oncology Group performance status of 0 or 1. They received 91 courses of therapy with i.v. IPO; 82 courses were administered daily for five days, and 9 were single bolus doses. The dose-limiting toxicity of elevated serum transaminases was observed in three of seven patients at 922 mg/m2/day. The maximum tolerated dose was 693 mg/m2/day on 5 consecutive days every 3 weeks. One patient developed grade 4 pulmonary toxicity at 167 mg/m2/day. There was no significant hematological or renal toxicity. No objective antitumor responses were observed. Pharmacokinetic analysis of 39 patients from day 1 of IPO administration showed biexponential elimination with mean half-lives of 8.6 (alpha half-life) and 76 min (beta half-life). There was a linear relationship between the area under the plasma drug concentration-time curve and the dose of IPO. There was no significant difference between the pharmacokinetic parameters measured on day 1 and day 5. Using a 4-day in vitro cytotoxicity assay, two tumor cell lines established from patients treated at 693 mg/m2/day had IC50s of approximately 6 mM, a concentration more than 75-fold higher than the plasma levels measured in these patients. Thus, although the total amount of drug administered per cycle on a daily times five dose schedule is more than 2.5-fold higher than the recommended single daily dose, IPO is unlikely to be a useful drug for patients with lung cancer.
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Antineoplásicos/administración & dosificación , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Neoplasias Pulmonares/tratamiento farmacológico , Terpenos/administración & dosificación , Adulto , Anciano , Antineoplásicos/efectos adversos , Antineoplásicos/farmacocinética , Esquema de Medicación , Femenino , Humanos , Enfermedades Pulmonares/inducido químicamente , Masculino , Persona de Mediana Edad , Tiempo de Tromboplastina Parcial , Terpenos/efectos adversos , Terpenos/farmacocinéticaRESUMEN
A capturing assay was used to monitor a Fab-antigen interaction using a BIACORE optical biosensor. The antigen, a truncated single-site mutant (F43V) version of the CD4 receptor, was captured onto the sensor surface using an immobilized nonneutralizing monoclonal antibody. While this assay design created an oriented antigen surface, the antigen slowly dissociated during subsequent binding of the Fab, thus complicating the binding responses. In this paper, we illustrate how binding events occurring on a decaying surface can be accurately described by globally fitting the response data to a model that accounts for the background surface decay. Support for the method was obtained by showing the equilibrium dissociation constant calculated from the kinetic rate constants (Kd = 2.20 +/- 0.01 nM) was similar to the value measured in solution using titration calorimetry (Kd = 2.6 +/- 0.5 nM). The ability to interpret rate constants from decaying surfaces significantly extends the types of experimental systems that can be quantitatively studied on optical biosensors.
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Técnicas Biosensibles , Antígenos CD4/metabolismo , Óptica y Fotónica , Reacciones Antígeno-Anticuerpo , Calorimetría/métodos , Fragmentos Fab de Inmunoglobulinas/metabolismo , Cinética , Propiedades de Superficie , TermodinámicaRESUMEN
Surface-based binding assays are often influenced by the transport of analyte to the sensor surface. Using simulated data sets, we test a simple two-compartment model to see if its description of transport and binding is sufficient to accurately analyze BIACORE data. First we present a computer model that can generate realistic BIACORE data. This model calculates the laminar flow of analyte within the flow cell, its diffusion both perpendicular and parallel to the sensor surface, and the reversible chemical reaction between analyte and immobilized reactant. We use this computer model to generate binding data under a variety of conditions. An analysis of these data sets with the two-compartment model demonstrates that good estimates of the intrinsic reaction rate constants are recovered even when mass transport influences the binding reaction. We also discuss the conditions under which the two-compartment model can be used to determine the diffusion coefficient of the analyte. Our results illustrate that this model can significantly extend the range of association rate constants that can be accurately determined from BIACORE.