RESUMEN
The in vivo release characteristics of protein-loaded biodegradable microspheres were examined in normal rats and severe combined immunodeficiency disease (SCID) mice. Bovine-derived superoxide dismutase (bSOD), encapsulated into microspheres comprised of poly(D,L-lactic-co-glycolic acid) and poly(D,L-lactic acid), was used as a model protein. Three types of bSOD-loaded microspheres with different release profiles were subcutaneously administered to normal rats. Anti-bSOD antibodies were first detected at day 9 after the administration of these microspheres, which was independent of their release profiles in vitro. A typical formulation with a sigmoidal release profile was subcutaneously administered to SCID mice. No immunoreaction was observed. The plasma bSOD concentration-time profile, determined by an enzyme-linked immunosorbent assay, well reflected the in vitro release profile of the formulation. The disappearance profile of active bSOD from the administration site also partly corresponded to both profiles. However, the relative bioavailability calculated with a profile on the subcutaneous injection of bSOD solution was 40.7%. These results indicated possible instability of bSOD released gradually at the administration site. The results of the present study using SCID mice would be suitable for discussing the in vitro-in vivo correlation of protein release from microspheres, and useful for designing long-term release formulations of protein drugs.
Asunto(s)
Superóxido Dismutasa/administración & dosificación , Animales , Biodegradación Ambiental , Disponibilidad Biológica , Bovinos , Masculino , Ratones , Ratones Endogámicos ICR , Ratones SCID , Microesferas , Ratas , Ratas Wistar , Superóxido Dismutasa/farmacocinéticaRESUMEN
T-0128 is a novel camptothecin (CPT) analogue (T-2513: 7-ethyl-10-aminopropyloxy-CPT)-carboxymethyl (CM) dextran conjugate via a Gly-Gly-Gly linker, with a molecular weight (MW) of 130 kDa. Our previous studies demonstrated that T-0128 has strong antitumor activity against human tumor xenografts that are highly refractory to CPT analogues attributable to the passive tumor targeting of released T-2513. This study examines the effects of carrier, dose, and tumor on T-0128 pharmacokinetics. To study carrier effect, tumor-bearing rats received one i.v. injection of fluorescein isothiocyanate (FITC)-labeled CM dextran with a different degree of substitution (DS) of the carboxymethylated groups and a different MW. Results showed that CM dextran from Dextran T-110 (MW 110 kDa) with a DS value of 0.4 is an appropriate drug carrier for T-0128 regarding plasma half-life and passive tumor targeting. To study dose and tumor effects, non-tumor- and tumor-bearing rats were treated with T-0128 doses ranging from 1 to 25 mg/kg (based on the amount of T-2513 bound to CM dextran). Dose-dependent pharmacokinetics of T-0128 were observed in both kinds of rats. The presence of tumor reduced the plasma half-life and systemic exposure of T-0128. The saturation of hepatic and splenic tissue uptake clearances (CLups), and a large contribution of the tumor CLup to the total body clearance explain these results. Overall, our data provide a rationale for the selection of the carrier for T-0128 and a need for pharmacokinetic studies to evaluate the influences of tumor on the drug disposition.
Asunto(s)
Antineoplásicos Fitogénicos/administración & dosificación , Antineoplásicos Fitogénicos/farmacocinética , Camptotecina/análogos & derivados , Dextranos/administración & dosificación , Dextranos/farmacocinética , Neoplasias Experimentales/metabolismo , Profármacos/administración & dosificación , Profármacos/farmacocinética , Topotecan/análogos & derivados , Topotecan/administración & dosificación , Topotecan/farmacocinética , Animales , Área Bajo la Curva , Secuencia de Carbohidratos , Línea Celular , Cromatografía , Femenino , Semivida , Macrófagos/metabolismo , Datos de Secuencia Molecular , Ratas , Ratas Wistar , Distribución TisularRESUMEN
A new method for preparing protein-loaded biodegradable microspheres by a process involving solid-in-oil-in-water (S/O/W) emulsion was established using poly(ethylene glycol) (PEG). In the first step, a protein solution was lyophilized with PEG, which resulted in the formation of spherical protein microparticles, less than 5 microm in diameter, dispersed in a continuous PEG phase. This process was well explained by the aqueous phase separation phenomenon induced by freezing-condensation. Since this lyophilizate could be directly dispersed in an organic phase containing biodegradable polymer by dissolving PEG with methylene chloride, a conventional in-water drying method could be adopted in the second step. Through this S/O/W emulsion process, horseradish peroxidase was effectively entrapped into monolithic-type microspheres of poly(DL-lactic-co-glycolic acid) (PLGA), without significant loss of activity. Bovine superoxide dismutase (bSOD), as another model protein, could be encapsulated into reservoir-type microspheres by the 'polymer-alloys method' using both poly(DL-lactic acid) (PLA) and PLGA. The initial release of bSOD from this reservoir-type microsphere was efficiently reduced. Further, the bSOD release kinetics could be suitably modified by adjusting the loading amounts of PEG or polymer composition. In this study, the multi-functional nature of PEG was successfully utilized in the preparation and designing of protein-loaded microspheres.
Asunto(s)
Emulsiones , Proteínas/administración & dosificación , Tecnología Farmacéutica , Animales , Bovinos , Ácido Láctico/administración & dosificación , Microesferas , Polietilenglicoles , Ácido Poliglicólico/administración & dosificación , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Polímeros/administración & dosificación , Superóxido Dismutasa/administración & dosificaciónRESUMEN
Clinically available camptothecins (CPTs), such as irinotecan (CPT-11) and topotecan, represent one of the most promising classes of antitumor agents, despite their toxicity. To improve their pharmacological profiles, a new macromolecular prodrug, denoted T-0128, was synthesized. This prodrug is a novel CPT analogue (T-2513)-carboxymethyl (CM) dextran conjugate via a triglycine spacer, with a molecular weight of Mr 130,000. This study was designed to test the concept that the rational design of a CPT-polymer conjugate would increase the efficacy of the parent drug. The in vivo antitumor study against Walker-256 carcinoma demonstrated that T-0128 was 10 times as active as T-2513, supporting this concept. Additionally, comparative efficacy studies of T-0128, T-2513, CPT-11, and topotecan were performed using a panel of human tumor xenografts in nude mice, showing the advantage of T-0128 over these CPTs. The maximal tolerated doses (MTDs) of T-0128, T-2513, and CPT-11 were comparable. Even a single i.v. injection of T-0128 at 6 mg/kg (based on the amount of T-2513 bound to CM dextran) induced complete regression of MX-1 mammary carcinoma. T-0128 at 10 mg/kg weekly for 3 weeks (one-tenth of its MTD) cured LX-1 lung carcinoma. Also, T-0128 below its MTD consistently cured or regressed St-4 gastric and HT-29 colorectal tumor xenografts that are highly refractory to CPTs. These demonstrate the broad range of therapeutic doses achieved with T-0128. Pharmacokinetic studies were performed to correlate the efficacy results obtained for T-0128 with plasma and tissue drug concentrations using Walker-256 tumor-bearing rats. Results showed that after i.v. administration of T-0128, the conjugate continued to circulate at a high concentration for an extended period, resulting in tumor accumulation. In the tumor, the sustained release of T-2513 occurred. In contrast, T-2513 disappeared rapidly from the body. The significant increases in the amount and exposure time of released T-2513 in the tumor explain well the enhanced efficacy of T-0128. In conclusion, this study indicated that T-0128 improved the potency of T-2513, demonstrating the proof of the above concept.
Asunto(s)
Neoplasias de la Mama/tratamiento farmacológico , Camptotecina/análogos & derivados , Dextranos/farmacología , Neoplasias Pulmonares/tratamiento farmacológico , Profármacos/farmacología , Topotecan/análogos & derivados , Animales , Camptotecina/farmacocinética , Ciclo Celular/efectos de los fármacos , Cromatografía en Gel , Cromatografía Líquida de Alta Presión , ADN-Topoisomerasas de Tipo I/metabolismo , Dextranos/química , Dextranos/farmacocinética , Relación Dosis-Respuesta a Droga , Femenino , Células HeLa , Humanos , Masculino , Ratones , Ratones Desnudos , Trasplante de Neoplasias , Profármacos/química , Profármacos/farmacocinética , Ratas , Ratas Wistar , Factores de Tiempo , Distribución Tisular , Topotecan/química , Topotecan/farmacocinética , Topotecan/farmacología , Células Tumorales CultivadasRESUMEN
It is not clear to what extent poor insight is inherent in schizophrenic psychopathology or is related to clinical factors. It is clinically important to elucidate this point to know how some insight remains intact in schizophrenia. Sixty-three ICD-10 schizophrenics were recruited. Insight was measured by David's three-dimensional scale, which deals with the awareness of the need for treatment, of the illness, and of psychotic experiences. Clinical factors that may influence insight were grouped into objective psychopathology, subjective experience, and treatment settings, according to the normal development of insight starting from objective illness, through subjective perception of it, to seeking treatment. Psychopathology was measured by the Brief Psychiatric Rating Scale (BPRS) and the Scale for the Assessment of Negative Symptoms (SANS), and the subjective experience was measured by a checklist of our own. Positive symptoms, especially disordered thought, hallucinations, and delusions, had a modest inverse correlation with awareness of illness and of psychotic experiences, but these were not correlated with alogia or other negative symptoms. Later age at the first onset was significantly correlated with poor awareness of psychotic experience, but no correlation of subjective experience with insight emerged. Awareness of the need for treatment was significantly higher in outpatient than in inpatient groups, and was not correlated with any other variables. Poor awareness of illness and of psychotic experience seems to be a trait of the acute rather than the chronic psychopathology of schizophrenia. Poor awareness of psychotic experience was related to later onset. Awareness of the need for treatment seems to improve, even in the absence of awareness of illness or of psychotic experience, in outpatient settings--the effects of social interaction may be relevant to this.
Asunto(s)
Esquizofrenia/complicaciones , Esquizofrenia/fisiopatología , Psicología del Esquizofrénico , Autoevaluación (Psicología) , Adulto , Edad de Inicio , Enfermedad Crónica/psicología , Trastornos del Conocimiento , Estudios Transversales , Femenino , Humanos , Japón , Masculino , Persona de Mediana Edad , Aceptación de la Atención de Salud , Análisis de Regresión , Índice de Severidad de la Enfermedad , Factores de TiempoRESUMEN
We had previously extracted two types of subjective experience of schizophrenia (SES); first, a feeling of inadequacy in stream of speech, thought, and action, associated with a distorted sense of self, and second, a feeling that excessive thoughts are filling and sticking to one's head, causing negative affective burden such as misery and oppression. This study tried to validate their content using conventional symptom clusters as external validators. Subjects were 63 patients from two hospitals in Tokyo meeting ICD-10 criteria for schizophrenia. Positive, negative, and depressive psychopathology were measured by the Brief Psychiatric Rating Scale (BPRS), Scale for the Assessment of the Negative Symptoms (SANS), and Hamilton's Depression Scale (HDS). The two types of SES were measured by an original scale. The first type of SES correlated significantly with the negative symptoms of alogia, avolition, and attention, whereas the second correlated with positive and depressive symptoms. To analyze how schizophrenia is experienced by patients, qualitative and comprehensive descriptions, such as indicated by our subjective factors, will be useful.
Asunto(s)
Psicología del Esquizofrénico , Autoimagen , Adulto , Afecto , Cognición , Femenino , Humanos , Japón , Masculino , Persona de Mediana EdadRESUMEN
A case of extramedullary plasmacytoma presenting with biclonal gammopathy is reported. The patient was an 82-year-old man in whom monoclonal-protein (M-protein) was not noted during his first hospitalization. On his second hospitalization generalized lymph node swelling and biclonal gammopathy (IgG-kappa, IgA-kappa) were observed. Histological findings were compatible with those of extramedullary plasmacytoma. In the terminal stages, the patient became cachexic. The autopsy disclosed dissemination of the plasmacytoma. Only two other cases have been reported in the literature, and a review of these previous reports is included.
Asunto(s)
Hipergammaglobulinemia/etiología , Plasmacitoma/complicaciones , Anciano , Anciano de 80 o más Años , Humanos , Hipergammaglobulinemia/inmunología , Masculino , Plasmacitoma/inmunologíaRESUMEN
Disposition characteristics of model macromolecules with different physicochemical characteristics and macromolecular prodrugs of mitomycin C, namely mitomycin C-dextran conjugates, were studied in tissue-isolated tumor preparations of Walker 256 carcinoma with the use of a single-pass vascular perfusion technique. In constant infusion experiments, all radiolabeled macromolecules accumulated in the tumor tissue, but the degree and pattern of distribution greatly varied, depending on their electric charges. Positively charged macromolecules were markedly accumulated compared with those that were neutral or negatively charged. In addition, their concentrations were significantly higher in viable than in necrotic regions, while neutral and negative compounds were distributed in necrotic rather than in viable regions. Pharmacokinetic analysis of tissue concentration-time courses of positively charged diethylaminoethyl and neutral dextrans showed that their movement occurred by convective fluid flow, and that high tissue accumulation of positively charged macromolecules could be explained by strong binding due to electrostatic interaction. For neutral and anionic macromolecules with negligible affinity to the tissue, it was suggested that the final concentration gradient between the viable and necrotic regions was decided by their tissue fluid content. Thus, the present study revealed the basic disposition characteristics of macromolecules in tumor tissue relative to their physicochemical properties.
Asunto(s)
Carcinoma 256 de Walker/metabolismo , Dextranos/farmacocinética , Espacio Extracelular/metabolismo , Mitomicina/farmacocinética , Profármacos/farmacocinética , Animales , Permeabilidad Capilar , Carcinoma 256 de Walker/irrigación sanguínea , Dextranos/administración & dosificación , Dextranos/química , Femenino , Mitomicina/administración & dosificación , Mitomicina/química , Perfusión , Profármacos/administración & dosificación , Profármacos/química , Ratas , Ratas EndogámicasAsunto(s)
Seudoquiste Pancreático/terapia , Enfermedades del Bazo/etiología , Adulto , Benzamidinas , Ceftizoxima/uso terapéutico , Colangiopancreatografia Retrógrada Endoscópica , Guanidinas/uso terapéutico , Humanos , Masculino , Seudoquiste Pancreático/complicaciones , Nutrición Parenteral Total , Enfermedades del Bazo/diagnóstico por imagen , Tomografía Computarizada por Rayos XRESUMEN
The prediction systems of chemical toxicity has been developed by means of structure-activity relationship based on the computerized fact database (BL-DB). Numbers and ratio of elements, side chains, bonding, position, and microenvironment of side chains were used as structural factors of the chemical for the prediction. Such information was obtained from the BL-DB database by Wiswesser line-formula chemical notation. In the present study, the Salmonella/microsome assay was chosen as indicative of the target toxicity of chemicals. A set of chemicals specified with mutagenicity data was retrieved, and necessary information was extracted and transferred to the working file. Rules of the relations between characteristics of chemical structure and the assay result are extracted as parameters for rules by experts on the rearranged data set. These were analyzed statistically by the discriminant analysis and the prediction with the rules were evaluated by the elimination method. Eight kinds of rules to predict Salmonella/microsome assay were constructed, and currently results of the assay on aliphatic and heterocyclic compounds can be predicted as accurately as +90%.
Asunto(s)
Bases de Datos Factuales , Sistemas Especialistas , Relación Estructura-Actividad , Toxicología , Algoritmos , Análisis Discriminante , Estructura Molecular , Pruebas de Mutagenicidad , Mutágenos/química , Mutágenos/toxicidad , Salmonella typhimurium/efectos de los fármacosRESUMEN
Duodenitis was investigated by endoscopy in 93 cases from among 1242 subjects. Endoscopic duodenitis was classified into three types endoscopically--reddening type, erosive type and nodular type. There was a relatively high correlation between the endoscopic and the histological diagnosis of duodenitis. Severely inflamed cases were found histologically more frequently in erosive- or nodular-type duodenitis than in reddening-type duodenitis. During the follow-up period, changes in endoscopic findings were observed more frequently, from the erosive type to the reddening type, and from the reddening type to normal. There were no cases which subsequently developed duodenal ulcers. We found a significantly high incidence of "endoscopic duodenitis" in uremic patients who had been given regular dialysis, and not in hepatic cirrhosis patients.