RESUMO
1. The purpose of the present study was to determine if central interleukin-1ß (IL1ß), interleukin-6 (IL6) and interleukin-8 (IL8) affect feeding behaviour in chicks (Gallus gallus) and examine if central interleukins are related to the lipopolysaccharide (LPS)-induced anorexia. 2. Intra-abdominal (IA) injection of LPS significantly suppressed feeding behaviour and significantly increased mRNA expression of IL1ß and IL8 in the diencephalon when compared to the control group, while IL6 tended to be increased. 3. Intracerebroventricular (ICV) injection of 200 ng IL1ß significantly decreased food intake at 60 min after the injection while IL6 and IL8 had no effect. 4. IA injection of these ILs (200 ng) had no effect on food intake in chicks. 5. ICV injection of 200 ng IL1ß did not affect water intake and plasma corticosterone concentration, suggesting that central IL1ß might not be related to the regulation of drinking behaviour and the hypothalamus-pituitary-adrenal axis. 6. The present study demonstrated that central IL1ß but not IL6 and IL8 might be related to the inhibition of feeding in chicks.
Assuntos
Galinhas/fisiologia , Comportamento Alimentar/efeitos dos fármacos , Expressão Gênica , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Interleucina-8/metabolismo , Lipopolissacarídeos/farmacologia , Animais , Corticosterona/sangue , Diencéfalo/metabolismo , Comportamento de Ingestão de Líquido/efeitos dos fármacos , Infusões Intraventriculares , Masculino , Especificidade de Órgãos , RNA Mensageiro/metabolismoRESUMO
OBJECTIVE: To assess the functional changes of Transient receptor potential vanilloid 1 (TRPV1) receptor and to clarify its mechanism in a rat mono-iodoacetate (MIA)-induced joint pain model (MIA rats), which has joint degeneration with cartilage loss similar to osteoarthritis. METHODS: Sensitization of TRPV1 in MIA rats was assessed by transient spontaneous pain behavior induced by capsaicin injection in knee joints and electrophysiological changes of dorsal root ganglion (DRG) neurons innervating knee joints in response to capsaicin. Mechanisms of TRPV1 sensitization were analyzed by a newly developed sandwich enzyme-linked immunosorbent assay that detects phosphorylated TRPV1, followed by functional and expression analyses of protein kinase C (PKC) in vivo and in vitro, which involves TRPV1 phosphorylation. RESULTS: Pain-related behavior induced by intra-articular injection of capsaicin was significantly increased in MIA rats compared with sham rats. In addition, capsaicin sensitivity, evaluated by capsaicin-induced inward currents, was significantly increased in DRG neurons of MIA rats. Protein levels of TRPV1 remained unchanged, but phosphorylated TRPV1 at Ser800 increased in DRG neurons of MIA rats. Phosphorylated-PKCÉ (p-PKCÉ) increased and co-localized with TRPV1 in DRG neurons of MIA rats. Capsaicin-induced pain-related behavior in MIA rats was inhibited by intra-articular pretreatment of the PKC inhibitor bisindolylmaleimide I. In addition, intra-articular injection of the PKC activator phorbol 12-myristate 13-acetate increased capsaicin-induced pain-related behavior in normal rats. CONCLUSION: TRPV1 was sensitized at the knee joint and at DRG neurons of MIA rats through PKC activation. Thus, TRPV1 sensitization might be involved in chronic pain caused by osteoarthritis.
Assuntos
Artralgia , Animais , Gânglios Espinais , Iodoacetatos , Proteína Quinase C , Ratos , Ratos Sprague-DawleyRESUMO
Basal-supported oral therapy (BOT) is often used to treat poorly controlled type 2 diabetes. However, patients sometimes experience nocturnal and early morning hypoglycemia. Thus, maintaining targeted glycemic control by BOT is limited in some patients. We assessed the efficacy and safety of replacing basal insulin by sitagliptin therapy in Japanese type 2 diabetes patients on BOT. Forty-nine subjects were sequentially recruited for the 52-week, prospective, single arm study. Patients on BOT therapy were switched from basal insulin to sitagliptin. The primary endpoint was change in HbA1c in 52 weeks. The secondary endpoints were dropout rate, changes in body weight, frequency of hypoglycemia, and relationship between change in HbA1c and insulin secretion capacity evaluated by glucagon loading test. The average dose of basal insulin was 15.0±8.4 units. Sixteen subjects (31.3%) were dropped because replacement by sitagliptin was less effective for glycemic control. In these subjects, diabetes duration was longer, FPG and HbA1c at baseline were higher, and insulin secretion capacity was lower. Change in HbA1c in 52 weeks was - 4 mmol/mol (95% CI - 5 to - 4 mmol/mol) (p<0.05). Change in body weight was - 0.71 kg (95% CI - 1.42 to - 0.004 kg) (p<0.05). Frequency of hypoglycemia was decreased from 1.21±1.05 to 0.06±0.24 times/month. HbA1c level was improved if C-peptide index (CPI) was over 1.19. In conclusion, basal insulin in BOT can be replaced by sitagliptin with a decrease in HbA1c level and frequency of hypoglycemia in cases where insulin secretion capacity was sufficiently preserved.
Assuntos
Povo Asiático , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Insulina/efeitos adversos , Insulina/uso terapêutico , Pirazinas/efeitos adversos , Pirazinas/uso terapêutico , Triazóis/efeitos adversos , Triazóis/uso terapêutico , Idoso , Índice de Massa Corporal , Peso Corporal/efeitos dos fármacos , Peptídeo C/sangue , Demografia , Diabetes Mellitus Tipo 2/complicações , Relação Dose-Resposta a Droga , Feminino , Hemoglobinas Glicadas/metabolismo , Humanos , Hipoglicemia/complicações , Hipoglicemia/tratamento farmacológico , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/efeitos adversos , Hipoglicemiantes/farmacologia , Insulina/administração & dosagem , Insulina/farmacologia , Japão , Masculino , Pirazinas/administração & dosagem , Pirazinas/farmacologia , Curva ROC , Fosfato de Sitagliptina , Resultado do Tratamento , Triazóis/administração & dosagem , Triazóis/farmacologiaRESUMO
An in situ technology for mitigating diffuse agricultural pollution using catch crops was developed for simultaneously preventing nitrate groundwater pollution, reducing nitrous oxide (N2O) gas emissions, and removing salts from the topsoil. Seasonal changes in the performance of a catch crop were investigated using lysimeters in a full-scale greenhouse experiment with 50 d cultivation of dent corn. Catch crop cultivation significantly reduced the leached mineral nitrogen by 89-91% in summer, 87-89% in spring, and 61-82% in winter, and it also significantly reduced the N2O emission by 68-84% in summer. The amounts of nitrogen uptake by the catch crop were remarkably higher than those of leached nitrogen and N2O emission in each season. Catch crop cultivation is a promising technology for mitigating diffuse agricultural pollution.
Assuntos
Poluentes Atmosféricos/química , Produtos Agrícolas , Nitratos/química , Óxido Nitroso/química , Estações do Ano , Poluentes Químicos da Água/química , Zea mays , Água Subterrânea/química , Solo/químicaRESUMO
INTRODUCTION: No study has investigated scan parameters in head and neck dual layer dual-energy computed tomography (DL-DECT). This study aimed to select the appropriate scan parameters in head and neck imaging by evaluating the scan parameter effects on the accuracies of CT numbers and conduct iodine quantification in DL-DECT. METHODS: A multi-energy phantom was scanned using a dual layer CT (DLCT) scanner. Reference materials of iodine, blood, calcium, and adipose were used. A helical scan was performed by using reference and several protocols. Iodine density and virtual monochromatic images (VMIs) at the energy of 50, 70, and 100 keV were reconstructed. The iodine concentrations and CT numbers in each protocol were measured. Moreover, the absolute percentage errors (APEs) of iodine quantifications and CT numbers (reference vs. each protocol) were compared. Equivalence was observed when APEs between reference and each protocol was within 5%. Statistical analysis was performed using appropriate software. RESULTS: The APEs between the high-tube-voltage and reference protocol were 23.7, 14.0, 8.8, and 8.1% for iodine reference materials with concentrations equal to 2, 5, 10, and 15 mg/ml, respectively. At 50 keV, APEs between the high-tube-voltage and reference protocols were greater than 5% except for calcium and adipose. At 100 keV, APEs between the high-tube-voltage and reference protocols were greater than 5% except for blood and calcium. CONCLUSIONS: The high-tube-voltage protocol improved the accuracies of the measurement for iodine quantification and CT numbers. Additionally, the scanning parameters except for tube voltage had no effect on accuracies of iodine quantitation and CT numbers in the DLCT scanner. IMPLICATIONS FOR PRACTICE: The use of the high-tube-voltage protocol will be recommended for more accurate material decomposition in head and neck DL-DECT.
Assuntos
Hominidae , Iodo , Humanos , Animais , Iodo/análise , Cálcio/análise , Japão , Tomografia Computadorizada por Raios X/métodos , HospitaisRESUMO
INTRODUCTION: Dual-energy computed tomography (DECT) can generate virtual non-contrast (VNC) images. Herein, we sought to improve the accuracy of VNC images by identifying the optimal slope of contrast media (SCM) for VNC-image generation based on the iodine concentration and subject's body size. METHODS: We used DECT to scan a multi-energy phantom including four iodine concentration rods (15, 10, 5, and 2 mg/mL), and 240 VNC images (eight SCM ranging from 0.49 to 0.56 × three body sizes × ten scans) that were generated by three-material decomposition. The CT number of each iodine and solid water rod part was measured in each VNC image. The difference in the CT number between the iodine and the solid water rod part was calculated and compared using paired t-test or repeated measures ANOVA. RESULTS: The SCM that achieved an absolute value of the difference in CT number of <5.0 Hounsfield units (HU) for all body sizes simultaneously was greater at lower iodine concentration (SCM of 0.5, 0.51, and 0.53 at 10, 5, and 2 mg/mL iodine, respectively). At an iodine concentration of 15 mg/mL, no SCM achieved an absolute difference of <5.0 HU in CT number for all body sizes simultaneously. At all iodine concentrations, the SCM achieving the minimal difference in the CT number increased with the increase in body size. CONCLUSION: By adjusting the SCM according to the iodine concentration and body size, it is possible to generate VNC images with an accuracy of <5.0 HU. IMPLICATIONS FOR PRACTICE: Improving the accuracy of VNC images minimizing incomplete iodine subtraction would make it possible to replace true non-contrast (TNC) images with VNC images and reduce the radiation dose.
Assuntos
Iodo , Tomografia Computadorizada por Raios X , Humanos , Tomografia Computadorizada por Raios X/métodos , Reprodutibilidade dos Testes , Imagens de FantasmasRESUMO
As a result of long-term continuous use of fertilizers in farm land, a large amount of nutrients accumulate in the soil, increasing the risk of eutrophication or nitrate pollution of groundwater. For rehabilitating the farm soil and recovering nutrients such as nitrogen, phosphorus and potassium, a new system has been developed by our research group. This paper discusses the methodology of extracting nutrients from biomass in order to recover phosphorus and other nutrients in crystal form. Around 80% or higher extraction rates were achieved for phosphorus and potassium by soaking the powdered tissue in distilled water or 1% NaOH solution for 24 h. The extracted phosphorus and potassium act as a potential resource for recycled fertilizer or other industrial materials.
Assuntos
Biomassa , Fertilizantes/análise , Poluentes do Solo/metabolismo , Zea mays/crescimento & desenvolvimento , Folhas de Planta/química , Caules de Planta/química , Sementes/química , Solo/química , Poluentes do Solo/química , Zea mays/metabolismoRESUMO
Tight junctions (TJs) maintain cellular polarity between the apical and basolateral region of epithelial cells. Claudin, a tetra-transmembrane protein, plays a pivotal role in the barrier function of TJs. We previously found that a claudin modulator, the C-terminal fragment of Clostridium perfringens enterotoxin (C-CPE), may be a promising candidate for improving the mucosal absorption of drugs. C-CPE is a fragment of enterotoxin, and putative CPE claudin receptors are highly expressed in liver and kidney. The safety and antigenicity of C-CPE must be evaluated for future clinical application. Therefore, we evaluated whether C-CPE administration in mice leads to tissue injury or production of antibodies. Intravenous administration of C-CPE at 5 mg/kg, which is a more than 25-fold higher dose than that used in a murine mucosal absorption model, did not increase biochemical markers of liver and kidney injury even after 11 injections once a week. Nasal C-CPE administration (2 mg/kg) once a week for 11 administrations also did not increase these biochemical markers, but 6 administrations of C-CPE resulted in elevation of C-CPE-specific serum IgG. These results indicate that development of a less antigenic claudin modulator will be essential for future clinical application of a C-CPE-based mucosal absorption enhancer.
Assuntos
Claudinas/efeitos dos fármacos , Enterotoxinas/toxicidade , Administração Intranasal , Animais , Claudinas/biossíntese , Relação Dose-Resposta a Droga , Enterotoxinas/química , Enterotoxinas/imunologia , Feminino , Imunoglobulina G/biossíntese , Injeções Intravenosas , Rim/efeitos dos fármacos , Rim/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Fragmentos de Peptídeos/farmacologia , Junções Íntimas/efeitos dos fármacos , Junções Íntimas/metabolismoRESUMO
It has been reported that the immunosuppressant rapamycin decreases the viability of pancreatic beta cells. In contrast, exendin-4, an analogue of glucagon-like peptide-1, has been found to inhibit beta cell death and to increase beta cell mass. We investigated the effects of exendin-4 on the cytotoxic effect of rapamycin in beta cells. Incubation with 10 nM rapamycin induced cell death in 12 h in murine beta cell line MIN6 cells and Wistar rat islets, but not when coincubated with 10 nM exendin-4. Rapamycin was found to increase phosphorylation of c-Jun amino-terminal kinase (JNK) and p38 in 30 minutes in MIN6 cells and Wistar rat islets while exendin-4 decreased their phosphorylation. Akt and extracellular signal-regulated kinase (ERK) were not involved in the cytoprotective effect of exendin-4. These results indicate that exendin-4 may exert its protective effect against rapamycin-induced cell death in pancreatic beta cells by inhibiting JNK and p38 signaling.
Assuntos
Antibióticos Antineoplásicos/antagonistas & inibidores , Antibióticos Antineoplásicos/toxicidade , Células Secretoras de Insulina/efeitos dos fármacos , MAP Quinase Quinase 4/antagonistas & inibidores , Peptídeos/farmacologia , Sirolimo/antagonistas & inibidores , Sirolimo/toxicidade , Peçonhas/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Western Blotting , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Meios de Cultura , Proteínas Quinases Dependentes de AMP Cíclico/fisiologia , Relação Dose-Resposta a Droga , Exenatida , MAP Quinases Reguladas por Sinal Extracelular/fisiologia , Citometria de Fluxo , Insulina/metabolismo , Secreção de Insulina , Células Secretoras de Insulina/patologia , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/metabolismo , Fosfatidilinositol 3-Quinases/fisiologia , Fosforilação/efeitos dos fármacos , Ratos , Ratos WistarRESUMO
How does the brain represent objects in the world? A proportion of cells in the temporal cortex of monkeys responds specifically to objects, such as faces, but the type of coding used by these cells is not known. Population analysis of two sets of such cells showed that information is carried at the level of the population and that this information relates, in the anterior inferotemporal cortex, to the physical properties of face stimuli and, in the superior temporal polysensory area, to other aspects of the faces, such as their familiarity. There was often sufficient information in small populations of neurons to identify particular faces. These results suggest that representations of complex stimuli in the higher visual areas may take the form of a sparse population code.
Assuntos
Discriminação Psicológica , Macaca/fisiologia , Neurônios/fisiologia , Lobo Temporal/fisiologia , Animais , Face , HumanosRESUMO
In Southeast Asian tropical rainforests, two events, severe droughts associated with the El Niño-Southern Oscillation and general flowering, a type of community-wide mass flowering, occur at irregular, supra-annual intervals. The relationship between these two supra-annual events and patterns of insect population fluctuations has yet to be clearly elucidated. Leaf beetles (Chrysomelidae) are major herbivores and flower-visitors of canopy trees, affecting their growth and reproduction and, in turn, affected by tree phenology; but their population fluctuations in the Southeast Asian tropics have not been extensively investigated. We examined population fluctuation patterns of the 34 most dominant chrysomelid species in relation to the two supra-annual events by conducting monthly light-trapping over seven years in a lowland dipterocarp forest in Borneo. Our results showed large community variation in population fluctuation patterns and a supra-annual (between-year) variation in abundance for most of the dominant chrysomelids that was significantly larger than the annual (within-year) variation. Specifically, in response to a severe drought in 1998, chrysomelid species exhibited different population responses. These results show that population fluctuations of individual species, rather than the entire assemblage, must be analyzed to determine the effects of changes in environmental conditions on the structure of insect assemblages in the tropics, especially in regions where supra-annual environmental changes are relatively more important than seasonal changes.
Assuntos
Besouros/fisiologia , Meio Ambiente , Flores/fisiologia , Árvores , Animais , Bornéu , Dinâmica Populacional , Especificidade da Espécie , Clima TropicalRESUMO
To prevent insufficiency of the triceps after total elbow arthroplasty, we have, since 2008, used a triceps-sparing ulnar approach. This study evaluates the clinical results and post-operative alignment of the prosthesis using this approach. We reviewed 25 elbows in 23 patients. There were five men and 18 women with a mean age of 69 years (54 to 83). There were 18 elbows with rheumatoid arthritis, six with a fracture or pseudoarthrosis and one elbow with osteoarthritis. Post-operative complications included one intra-operative fracture, one elbow with heterotopic ossification, one transient ulnar nerve palsy, and one elbow with skin necrosis, but no elbow was affected by insufficiency of the triceps. Patients were followed for a mean of 42 months (24 to 77). The mean post-operative Japanese Orthopaedic Association Elbow Score was 90.8 (51 to 100) and the mean Mayo Elbow Performance score 93.8 (65 to 100). The mean post-operative flexion/extension of the elbow was 135°/-8°. The Manual Muscle Testing score of the triceps was 5 in 23 elbows and 2 in two elbows (one patient). The mean alignment of the implants examined by 3D-CT was 2.8° pronation (standard deviation (sd) 5.5), 0.3° valgus (sd 2.7), and 0.7° extension (sd 3.2) for the humeral component, and 9.3° pronation (sd 9.7), 0.3° valgus (sd 4.0), and 8.6° extension (sd 3.1) for the ulnar component. There was no radiolucent line or loosening of the implants on the final radiographs. The triceps-sparing ulnar approach allows satisfactory alignment of the implants, is effective in preventing post-operative triceps insufficiency, and gives satisfactory short-term results.
Assuntos
Artroplastia de Substituição do Cotovelo/métodos , Ulna/cirurgia , Idoso , Idoso de 80 Anos ou mais , Artroplastia de Substituição do Cotovelo/instrumentação , Prótese de Cotovelo , Feminino , Humanos , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/cirurgia , Complicações Pós-Operatórias/epidemiologia , Resultado do TratamentoRESUMO
The homogenate from Caco-2 cells of day 13 or 15 after subculturing had high omega-hydroxylation activity of docosahexaenoic acid (22:6(n-3)) or arachidonic acid (20:4(n-6)). Activity, maximal at pH 8.0, was inhibited in the presence of CO or metyrapone and in the absence of NADPH. Omega-hydroxylation activity of lauric acid in the homogenate was not detected. Apparent Michaelis constant (Km) values for 22:6(n-3) and 20:4(n-6) were found to be 4 and 7 microM. Omega-hydroxylation activity considerably increased with growth up to day 13 and then decreased until day 20 even though alkaline phosphatase (ALP) and leucine-aminopeptidase (LAP) activity increased with growth to day 20. Metyrapone in cultures caused omega-hydroxylation, ALP and LAP activity to decrease, while sodium butyrate dose-dependently increased that of omega-hydroxylation, ALP and an endogenous endonuclease and decreased lactate dehydrogenase (LDH) activity in culture medium. The omega-hydroxylation system thus appears quite likely to be associated with cytochrome P450, differentiation and/or apoptosis rather than cytotoxic cell death of Caco-2 cells. Substrate specificity, however, differed from that of human cytochrome P450 4A11.
Assuntos
Adenocarcinoma/metabolismo , Ácido Araquidônico/metabolismo , Ácidos Docosa-Hexaenoicos/metabolismo , Fosfatase Alcalina/metabolismo , Butiratos/farmacologia , Ácido Butírico , Células CACO-2 , Diferenciação Celular , Humanos , Hidroxilação , Leucil Aminopeptidase/metabolismoRESUMO
A useful marker for detecting minimal residual disease (MRD) has not been established yet in retinoblastoma. We assessed neuroendocrine protein gene product 9.5 (PGP9.5) expression, one of the markers for detecting MRD in neuroblastoma, in a patient with disseminated retinoblastoma. A 3-year-old boy with disseminated retinoblastoma in multiple bones and marrow was referred to our hospital. He received intensive treatment and has maintained CR for 48 months following myeloablative chemotherapy with hematopoietic stem cell transplantation (SCT). PGP9.5 expression was serially assessed by RT-PCR in peripheral blood mononuclear cells (PBMC), bone marrow cells (BMC) and mobilized peripheral blood stem cells (PBSC). Initially, his BMC consisted of 96% tumor cells which were proved to express PGP9.5 by RT-PCR. Moreover, PBMC were found to be positive for PGP9.5 indicating the presence of tumor cells in the peripheral blood. After intensive chemotherapy, PGP9.5 expression became negative in both PBMC and BMC. Prior to SCT, PBSC and BMC transplants were confirmed negative for PGP9.5 expression. It is suggested that PGP9.5 expression is a useful marker for evaluating therapeutic effects as well as detecting MRD in retinoblastoma.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Transplante de Células-Tronco Hematopoéticas , Neoplasia Residual/diagnóstico , Neoplasias da Retina/patologia , Retinoblastoma/patologia , Tioléster Hidrolases/genética , Criança , Terapia Combinada , Humanos , Masculino , Neoplasia Residual/genética , Reação em Cadeia da Polimerase , Neoplasias da Retina/tratamento farmacológico , Neoplasias da Retina/genética , Retinoblastoma/genética , Retinoblastoma/terapia , Tioléster Hidrolases/análise , Transplante Autólogo , Ubiquitina TiolesteraseRESUMO
The prostacyclin production of the gastroepiploic artery (GEA) and saphenous vein (SV) were studied in 5 patients undergoing coronary artery revascularization. The GEA produced 90.0 +/- 11.9, 132.4 +/- 13.7, and 191.1 +/- 21.8 pg/mg tissue (mean +/- standard error of the mean) of 6-keto-prostaglandin F1 alpha (prostacyclin metabolite) after 2.5, 5.0, and 10.0 minutes, respectively, of incubation in Krebs-Henseleit buffer at 37 degrees C. The SV produced 39.8 +/- 7.0, 66.7 +/- 9.1, and 123.6 +/- 15.1 pg/mg tissue of 6-keto prostaglandin F1 alpha after 2.5, 5.0, and 10.0 minutes, respectively, of incubation. The GEA produced significantly more 6-keto-prostaglandin F1 alpha than SV at all three sampling times up to ten minutes of incubation (p less than 0.01). Prostacyclin is a potent vasodilator and an inhibitor of platelet aggregation. Prostacyclin production by the internal mammary artery was reported to be much higher than that of SV, and the patency rate of internal mammary artery grafts is reported to be better than that of SV grafts in coronary artery revascularization. Therefore, our results suggest that the patency rate of GEA grafts may be better than that of SV grafts in coronary artery revascularization. The GEA is a promising and excellent graft from the biochemical point of view.
Assuntos
Artérias/metabolismo , Epoprostenol/biossíntese , Veia Safena/metabolismo , 6-Cetoprostaglandina F1 alfa/biossíntese , Vasos Coronários/cirurgia , Humanos , Técnicas In Vitro , Omento/irrigação sanguínea , Estômago/irrigação sanguínea , Grau de Desobstrução VascularRESUMO
Fractal geometry was applied to quantify the complexity of an internal structure of a porous film prepared with ethylcellulose (EC) and diethylphthalate (DEP) as a plasticizer. EC was dissolved together with DEP in a water-ethanol mixture solution, and then evaporated on Teflon petri dishes in order to make porous EC films. Boundary lines of the porous structures in the EC film cross section were taken by a confocal laser microscope as image data, and these images were fed into a computer to estimate the fractal dimension. The porous structure in EC film was observed to be a typical fractal and its complexity was quantified as a non-integral fractal dimension. No clear correlation was observed between the fractal dimension and the porosity of EC films, suggesting that they were mutually independent parameters representing the porous structure in the EC films. The permeation of theophylline through the EC films was determined by using two-chamber diffusion cells. A fairly good relationship between the permeability coefficient of theophylline and the fractal dimensions was observed, suggesting the usefulness of the fractal dimension as a novel parameter for evaluating drug permeation through porous films.
Assuntos
Celulose/análogos & derivados , Sistemas de Liberação de Medicamentos , Celulose/administração & dosagem , PermeabilidadeRESUMO
Chlorophyllin (CHL), a water-soluble derivative of chlorophyll, forms molecular complexes with heterocyclic amine mutagens in vitro. In a previous study [Dashwood and Guo (1993): Environ Mol Mutagen, 22:164-171], we observed an inverse correlation between the binding constants of several mutagen-CHL complexes and the antimutagenic potency of CHL in the Salmonella assay. The present investigation utilized molecular mechanics methods of energy minimization and spectrophotometric titration to examine structural features of chlorophylls, chlorins, and porphyrins that might be important for complex formation with heterocyclic amines. The exocyclic amine group of the mutagen aligned consistently with acid groups in CHL, suggesting that H-bond or electrostatic interactions facilitate complex formation. Replacement of the exocyclic amine with a nitro group abrogated this specific orientation and raised the minimized energies of the complexes. No relationship was found between complex strength and the specific positions of amine or methyl groups on the mutagen. However, the presence of methyl groups increased the minimized energies and lowered the binding constants of the complexes, perhaps due to partial disruption of pi-pi interaction by steric effects. All of the compounds examined, including chlorophyll a, required the presence of pi-pi interactions to form stable complexes with the heterocyclic amines. In general, the present results were in agreement with the inhibitory potency of each compound in the Salmonella assay, and they provide further support for the hypothesis that chlorophylls in the diet might act as interceptor molecules of food-borne carcinogens and mutagens.
Assuntos
Aminas/química , Antimutagênicos/química , Clorofila/química , Compostos Heterocíclicos/química , Mutagênicos/química , Antimutagênicos/farmacologia , Fenômenos Químicos , Físico-Química , Clorofila/farmacologia , Cinética , Modelos Moleculares , Testes de Mutagenicidade , Salmonella typhimurium/efeitos dos fármacos , Espectrofotometria , Relação Estrutura-AtividadeRESUMO
The i.v. LD50 values to mice of pure venoms of Vespa mandarinia japonica, V. simillima xanthoptera, V. tropica deusta and V. l. luctuosa were, respectively, 4.1, 3.1, 2.8 and 1.6 mg/kg. The LD50 value of 1.6 mg/kg distinguishes the venom of V. luctuosa as the most lethal known wasp venom. To measure the absolute lethality of a single sting, a new index, called lethal capacity, based on the amount of venom possessed by an individual and its lethality is presented. V. mandarinia and V. tropica are the most venomous known insects, with a lethal capacity of one sting from V. mandarinia delivering an LD50 (i.v.) dosage of venom to 270 g of mouse. The lethal capacity for an entire hornet colony, called colony lethal capacity, for V. tropica is 84 kg of mouse/colony.
Assuntos
Venenos de Abelha/toxicidade , Venenos de Vespas/toxicidade , Animais , Injeções Intraperitoneais , Injeções Intravenosas , Injeções Subcutâneas , Dose Letal Mediana , Camundongos , Especificidade da Espécie , Venenos de Vespas/administração & dosagemRESUMO
The responses of the cat's visual cortical cells to an optimally oriented (O-) and an inclined (theta-) slit have been studied. Cell's responses to the simultaneous presentation, in simple cells, are similar to those to theta-slit alone, but in complex cells, are remarkably decreased at orientation difference of about 45 degrees. In the sequential presentation, the effects of preceding theta-slit on the responses to the following O-slit decrease as the orientation difference increases. This suggests that neural interactions of simultaneous and sequential presentation of two slits are caused by different mechanisms.
Assuntos
Percepção de Forma/fisiologia , Neurônios/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Córtex Visual/fisiologia , Vias Visuais/fisiologia , Animais , Gatos , Rotação , Fatores de TempoRESUMO
The effect of a new antiherpetic compound of very low toxicity called acycloguanosine (Wellcome 248U) on herpetic ulcers in rabbit cornea was studied by the Corneal Epithelial Lesion Therapeutic Assay (CELTA). The therapeutic effect of 3% acycloguanosine ointment on dendritic ulcers was equal to that of 0.5% 5-iodo-2'-deoxyuridine (IDU) ointment. No toxic symptoms could be detected by slit-lamp on 4 days' treatment with this concentration of acycloguanosine. Because of its selective action on virus only, its extremely low toxicity in animals, and its availability for systemic administration, acycloguanosine seems to be an ideal antiviral compound for use in the treatment not only of herpetic keratitis but also of other herpetic diseases in man.