RESUMO
BACKGROUND: Male pseudohermaphroditism is a developmental anomaly wherein animals are genetically and gonadally male, but their internal and/or external genitalia resemble those of females. In cattle, pseudohermaphroditism is often accompanied by multiple severe malformations. To the best of our knowledge, this is the first report of male pseudohermaphroditism in a complex malformed calf born with an acardius amorphous cotwin. CASE PRESENTATION: This report describes the case of a three-day-old, male anurous Japanese Black calf born with an acardius amorphous cotwin, complete absence of the tail, agenesis of the anus, separate scrota, and umbilical hernia. Transthoracic echocardiography and computed tomography revealed serious malformations in the skeletal system and the circulatory, digestive, urinary, and genital organs. Necropsy revealed rectal atresia, immature testes, epididymis, and penis, but no male accessory gonads. Histological analyses revealed vaginal- and uterine-like tissues adjacent to or fused to the rectum. Fluorescence in situ hybridization detected X and Y chromosomes, and some cells presented two X-probe signals in the same nucleus. CONCLUSIONS: In contrast to the male genitalia, the female genitalia derived from the Müllerian ducts were difficult to detect by necropsy in the presented case. Many similar cases may be overlooked in clinical practice.
Assuntos
Anormalidades Múltiplas , Doenças dos Bovinos , Transtorno 46,XY do Desenvolvimento Sexual , Cardiopatias Congênitas , Masculino , Animais , Bovinos , Feminino , Hibridização in Situ Fluorescente/veterinária , Transtorno 46,XY do Desenvolvimento Sexual/veterinária , Genitália Feminina , Reto , Vagina , Anormalidades Múltiplas/veterinária , Cardiopatias Congênitas/veterináriaRESUMO
A 2-day-old male black calf presented with neurological symptoms, including opisthotonus. It was unable to stand due to hindquarter paresis. At 5 days old, the calf was able to stand, but exhibited a crossed forelimb gait. Computed tomography and magnetic resonance imaging revealed the expansion of the sutures between the squamous-lateral part of the occipital bone and between the occipital-temporal bone, cerebellar tonsillar herniation, posterior displacement of the brainstem, and cervical syringomyelia at 12 days old. This is the first case report of a live calf diagnosed with Arnold Chiari malformation classified as Chiari type 1.5 malformation in humans.
Assuntos
Malformação de Arnold-Chiari , Doenças dos Bovinos , Animais , Bovinos , Humanos , Masculino , Malformação de Arnold-Chiari/diagnóstico por imagem , Malformação de Arnold-Chiari/veterinária , Doenças dos Bovinos/diagnóstico por imagem , Imageamento por Ressonância Magnética/veterinária , Siringomielia/diagnóstico por imagem , Siringomielia/veterinária , Osso Temporal , Tomografia Computadorizada por Raios X/veterináriaRESUMO
As a result of the 2011 nuclear incident that occurred at the Fukushima Nuclear Power Plant, a large number of abandoned dogs and cats were left within the disaster zone. A small number of these animals were rescued and cared for at shelters. Prior to the dispersal of these animals to their owners or fosterers, we evaluated the degree of internal radiocesium contamination using a specially designed whole-body counter. We conducted 863 non-invasive measurements of gamma rays due to internal radioactive cesium for 68 dogs and 120 cats at one shelter. After plotting graphs of 137Cs density we generated exponential functions of decay from seven dogs and six cats. From the regression formulae, we were able to determine the biological half-lives as 38.2 days for dogs and 30.8 days for cats. We found that in dogs there was a correlation between the biological half-life of radioactive cesium and age. Using our data, we estimated whole-body densities for each cat and dog at the time when they were rescued. We found that there were deviations in the data distributions among the different species, likely due to the timing of rescue, or living habits prior to rescue. A significant correlation was found when extracted feline reproductive organs were analyzed; the coefficients for the estimation of whole-body densities were approximately 7-fold higher than those based on the extracted feline reproductive organs. This may be due to the fact that majority of the radioactive cesium accumulates within muscular tissue with less distribution in other organs. It is possible to plan the appropriate management period in an animal shelter based on the use of the biological half-life of radioactive cesium calculated in this study. We believe that the correlations we uncovered in this work would be of great use for the management of companion animals in the event of a future nuclear accident.
Assuntos
Radioisótopos de Césio/análise , Césio/análise , Acidente Nuclear de Fukushima , Monitoramento de Radiação/métodos , Contagem Corporal Total/métodos , Animais , Gatos , Desastres , Cães , Meia-Vida , Japão , Centrais Nucleares , RadioatividadeRESUMO
CASE DESCRIPTION: A 16-year-old 6.8-kg (15-lb) castrated male domestic shorthair cat was evaluated because of a 3 × 6-cm mass in the right medial lobe of the liver. CLINICAL FINDINGS: The cat had a history of frequent vomiting and anorexia along with 10% weight loss over the past year. TREATMENT AND OUTCOME: Transcatheter arterial embolization was selected because surgery (standard first-line treatment) was declined and only 1 vessel feeding the tumor was apparent on contrast-enhanced CT. A 4F sheath was placed in the left carotid artery, and a 3.3F guide catheter was advanced into the celiac artery. A 0.014-inch guidewire and 1.7F microcatheter were inserted into the hepatic artery through the guiding catheter and advanced into the feeding vessel. A mixture of polyvinyl alcohol particles and contrast agent was injected for embolization. A hypoechoic area in the tumor was identified on ultrasonography on posttreatment day 6, and necrotic and degenerated cells in the area were identified cytologically. By posttreatment day 71, vomiting had resolved and CT revealed decreased tumor size, but altered attenuation suggested a more solid mass on day 205. No feeding vessel for embolization was found on contrast-enhanced CT, so ultrasonic emulsification to remove the tumor was performed on day 231. No recurrence was seen on contrast-enhanced CT on day 420 or day 721. CLINICAL RELEVANCE: Findings suggested that transcatheter arterial embolization may be suitable for treating hepatic tumors in cats, but alternative approaches are needed in cats, compared with dogs, owing to anatomic differences.
Assuntos
Carcinoma Hepatocelular/veterinária , Doenças do Gato/cirurgia , Quimioembolização Terapêutica/veterinária , Neoplasias Hepáticas/veterinária , Animais , Carcinoma Hepatocelular/irrigação sanguínea , Carcinoma Hepatocelular/terapia , Gatos , Quimioembolização Terapêutica/métodos , Meios de Contraste , Iohexol/farmacologia , Neoplasias Hepáticas/irrigação sanguínea , Neoplasias Hepáticas/terapia , Masculino , Álcool de Polivinil/farmacologiaRESUMO
Ionising radiation-induced bystander effects are well recognised, but its dependence on dose or linear energy transfer (LET) is still a matter of debate. To test this, 49 sites in confluent cultures of AG01522D normal human fibroblasts were targeted with microbeams of carbon (103 keV µm(-1)), neon (375 keV µm(-1)) and argon ions (1260 keV µm(-1)) and evaluated for the bystander-induced formation of micronucleus that is a kind of a chromosome aberration. Targeted exposure to neon and argon ions significantly increased the micronucleus frequency in bystander cells to the similar extent irrespective of the particle numbers per site of 1-6. In contrast, the bystander micronucleus frequency increased with increasing the number of carbon-ion particles in a range between 1 and 3 particles per site and was similar in a range between 3 and 8 particles per site. These results suggest that the bystander effect of heavy ions for micronucleus formation depends on dose.
Assuntos
Efeito Espectador/efeitos da radiação , Fibroblastos/fisiologia , Fibroblastos/efeitos da radiação , Íons Pesados/efeitos adversos , Micronúcleos com Defeito Cromossômico/efeitos da radiação , Células Cultivadas , Fibroblastos/citologia , Humanos , Transferência Linear de Energia/efeitos da radiação , Doses de RadiaçãoRESUMO
Brown adipose tissue (BAT) plays an important role in thermoregulation in species living in cold environments, given heat can be generated from its chemical energy reserves. Here we investigate the existence of BAT in blubber in four species of delphinoid cetacean, the Pacific white-sided and bottlenose dolphins, Lagenorhynchus obliquidens and Tursiops truncates, and Dall's and harbour porpoises, Phocoenoides dalli and Phocoena phocoena. Histology revealed adipocytes with small unilocular fat droplets and a large eosinophilic cytoplasm intermingled with connective tissue in the innermost layers of blubber. Chemistry revealed a brown adipocyte-specific mitochondrial protein, uncoupling protein 1 (UCP1), within these same adipocytes, but not those distributed elsewhere throughout the blubber. Western blot analysis of extracts from the inner blubber layer confirmed that the immunohistochemical positive reaction was specific to UCP1 and that this adipose tissue was BAT. To better understand the distribution of BAT throughout the entire cetacean body, cadavers were subjected to computed tomography (CT) scanning. Resulting imagery, coupled with histological corroboration of fine tissue structure, revealed adipocytes intermingled with connective tissue in the lowest layer of blubber were distributed within a thin, highly dense layer that extended the length of the body, with the exception of the rostrum, fin and fluke regions. As such, we describe BAT effectively enveloping the cetacean body. Our results suggest that delphinoid blubber could serve a role additional to those frequently attributed to it: simple insulation blanket, energy storage, hydrodynamic streamlining or contributor to positive buoyancy. We believe delphinoid BAT might also function like an electric blanket, enabling animals to frequent waters cooler than blubber as an insulator alone might otherwise allow an animal to withstand, or allow animals to maintain body temperature in cool waters during sustained periods of physical inactivity.
Assuntos
Tecido Adiposo Marrom/diagnóstico por imagem , Golfinhos/anatomia & histologia , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Marrom/fisiologia , Animais , Regulação da Temperatura Corporal , Golfinhos/metabolismo , Golfinhos/psicologia , Canais Iônicos/genética , Canais Iônicos/metabolismo , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Gordura Subcutânea/diagnóstico por imagem , Gordura Subcutânea/metabolismo , Gordura Subcutânea/fisiologia , Tomografia Computadorizada por Raios X , Proteína Desacopladora 1RESUMO
Using heavy-ion microbeam, we report target irradiation of selected compartments within the diapause-terminated egg and its mutational consequences in the silkworm, Bombyx mori. On one hand, carbon-ion exposure of embryo to 0.5-6 Gy increased the somatic mutation frequency, suggesting targeted radiation effects. On the other, such increases were not observed when yolk was targeted, suggesting a lack of nontargeted bystander effect.
Assuntos
Bombyx/embriologia , Bombyx/efeitos da radiação , Embrião não Mamífero/fisiologia , Embrião não Mamífero/efeitos da radiação , Mutação/efeitos da radiação , Óvulo/fisiologia , Óvulo/efeitos da radiação , Animais , Relação Dose-Resposta à Radiação , Íons Pesados , Doses de RadiaçãoRESUMO
The aim of the present study was to clarify the mechanisms of cell death induced by heavy-ion irradiation focusing on the bystander effect in human lung cancer A549 cells. In microbeam irradiation, each of 1, 5, and 25 cells under confluent cell conditions was irradiated with 1, 5, or 10 particles of carbon ions (220 MeV), and then the surviving fraction of the population was measured by a clonogenic assay in order to investigate the bystander effect of heavy-ions. In this experiment, the limited number of cells (0.0001-0.002%, 5-25 cells) under confluent cell conditions irradiated with 5 or 10 carbon ions resulted in an exaggerated 8-14% increase in cell death by clonogenic assay. However, these overshooting responses were not observed under exponentially growing cell conditions. Furthermore, these responses were inhibited in cells treated with an inhibitor of gap junctional intercellular communication (GJIC), whereas they were markedly enhanced by the addition of a stimulator of GJIC. The present results suggest that bystander cell killing by heavy-ions was induced mainly by direct cell-to-cell communication, such as GJIC, which might play important roles in bystander responses.
Assuntos
Efeito Espectador/efeitos da radiação , Junções Comunicantes/fisiologia , Íons Pesados , Neoplasias Pulmonares/genética , Técnicas de Cultura de Células , Morte Celular/genética , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos da radiação , Ensaio de Unidades Formadoras de Colônias , Relação Dose-Resposta à Radiação , Humanos , Neoplasias Pulmonares/patologiaRESUMO
Classical studies on root hydrotropism have hypothesized the importance of columella cells as well as the de novo gene expression, such as auxin-inducible gene, at the elongation zone in hydrotropism; however, there has been no confirmation that columella cells or auxin-mediated signaling in the elongation zone are necessary for hydrotropism. We examined the role of root cap and elongation zone cells in root hydrotropism using heavy-ion and laser microbeam. Heavy-ion microbeam irradiation of the elongation zone, but not that of the columella cells, significantly and temporarily suppressed the development of hydrotropic curvature. However, laser ablation confirmed that columella cells are indispensable for hydrotropism. Systemic heavy-ion broad-beam irradiation suppressed de novo expression of INDOLE ACETIC ACID 5 gene, but not MIZU-KUSSEI1 gene. Our results indicate that both the root cap and elongation zone have indispensable and functionally distinct roles in root hydrotropism, and that de novo gene expression might be required for hydrotropism in the elongation zone, but not in columella cells.
Assuntos
Arabidopsis/fisiologia , Arabidopsis/efeitos da radiação , Raízes de Plantas/fisiologia , Raízes de Plantas/efeitos da radiação , Tropismo/fisiologia , Tropismo/efeitos da radiação , Água/farmacologia , Arabidopsis/efeitos dos fármacos , Relação Dose-Resposta à Radiação , Íons Pesados , Lasers , Raízes de Plantas/efeitos dos fármacos , Plantas , Doses de Radiação , Tropismo/efeitos dos fármacosRESUMO
Research concerning cellular responses to low dose irradiation, radiation-induced bystander effects, and the biological track structure of charged particles has recently received particular attention in the field of radiation biology. Target irradiation employing a microbeam represents a useful means of advancing this research by obviating some of the disadvantages associated with the conventional irradiation strategies. The heavy-ion microbeam system at JAEA-Takasaki, which was planned in 1987 and started in the early 1990's, can provide target irradiation of heavy charged particles to biological material at atmospheric pressure using a minimum beam size 5 mum in diameter. A variety of biological material has been irradiated using this microbeam system including cultured mammalian and higher plant cells, isolated fibers of mouse skeletal muscle, silkworm (Bombyx mori) embryos and larvae, Arabidopsis thaliana roots, and the nematode Caenorhabditis elegans. The system can be applied to the investigation of mechanisms within biological organisms not only in the context of radiation biology, but also in the fields of general biology such as physiology, developmental biology and neurobiology, and should help to establish and contribute to the field of "microbeam biology".
Assuntos
Ciclotrons/instrumentação , Íons Pesados , Radiobiologia/instrumentação , Radiobiologia/métodos , Animais , Automação/instrumentação , Células/efeitos da radiação , Desenho de Equipamento , Japão , Plantas/efeitos da radiação , RadiometriaRESUMO
An analysis of ionizing radiation-induced damage in peripheral lymphocytes has been employed to predict the prognosis of radiotherapy in terms of toxicity in normal tissues. Therefore, understanding the sensitivity of lymphocytes to high linear energy transfer (LET)-charged particles would be indispensable for utilizing charged particle therapy in veterinary medicine. However, the availability of such information is very limited. This study aimed to compare the radiosensitivity of feline T lymphocytes to gamma-rays (0.2 keV/microm) and 4 different types of charged particles with LET values ranging from 2.8 to 114 keV/microm. It was observed that the relative biological effectiveness, inactivation cross-section, and isodose-induced apoptosis increased in an LET-dependent manner. On the other hand, no difference in apoptosis frequency was observed in the cells exposed to an isosurvival dose of all the radiation types tested. This is the first study that demonstrates the LET dependence of cell killing and apoptosis induction in feline T lymphocytes. Our results suggest that lymphocytes can be effectively used to predict the prognosis of charged-particle therapy in cat patients.
Assuntos
Carbono/farmacologia , Gatos , Íons Pesados/efeitos adversos , Linfócitos T/efeitos da radiação , Animais , Apoptose , Células Cultivadas , Relação Dose-Resposta à Radiação , Raios gamaRESUMO
The effects of heavy ion microbeams on muscle fibers isolated from mouse skeletal muscles were examined by electron microscopy. The plasma membranes of heavy ion beam-irradiated areas of muscle fibers showed irregular protrusions and invaginations. In the cytoplasm, an irregular distribution of microfilaments was found near the plasma membrane. Sarcoplasmic reticula in the irradiated regions showed a distended appearance with flocculent material within the lumen. These changes were seen as early as 2 min after irradiation, and persisted until as late as 22 min after irradiation. Many autophagic vacuoles could be seen at 7 min after irradiation. At 22 min, the vacuoles became more prominent and showed more variety. These observations suggest that heavy ion beam irradiation causes disruption of the cellular architecture and the autophagy is involved in removal of this disruption.
Assuntos
Autofagia , Fibras Musculares Esqueléticas/efeitos da radiação , Fibras Musculares Esqueléticas/ultraestrutura , Animais , Células Cultivadas , Feminino , Íons Pesados , Camundongos , Microscopia Eletrônica de Transmissão , Músculo Esquelético/efeitos da radiação , Músculo Esquelético/ultraestruturaRESUMO
To carry out the radio-microsurgery study using silkworm, Bombyx mori, we have already developed the specific irradiation systems for eggs and third to fifth instar larvae. In this study, a modified application consisting of the first instar silkworm larvae was further developed using heavy-ion microbeams. This system includes aluminum plates with holes specially designed to fix the first instar silkworm larvae during irradiation, and Mylar films were used to adjust energy deposited for planning radiation doses at certain depth. Using this system, the suppression of abnormal proliferation of epidermal cells in the knob mutant was examined. Following target irradiation of the knob-forming region at the first instar stage with 180-mum-diameter microbeam of 220 MeV carbon (12C) ions, larvae were reared to evaluate the effects of irradiation. The results indicated that the knob formation at the irradiated segment was specially suppressed in 5.9, 56.4, 66.7 and 73.6% of larvae irradiated with 120, 250, 400 and 600 Gy, respectively, but the other knob formations at the non-irradiated segments were not suppressed in either irradiation. Although some larva did not survive undesired non-targeted exposure, our present results indicate that this method would be useful to investigate the irradiation effect on a long developmental period of time. Moreover, our system could also be applied to other species by targeting tissues, or organs during development and metamorphosis in insect and animals.
Assuntos
Padronização Corporal/efeitos da radiação , Bombyx/embriologia , Bombyx/efeitos da radiação , Íons Pesados , Irradiação Corporal Total/instrumentação , Animais , Bombyx/crescimento & desenvolvimento , Relação Dose-Resposta à Radiação , Desenho de Equipamento , Análise de Falha de Equipamento , Larva/crescimento & desenvolvimento , Larva/efeitos da radiação , Doses de Radiação , Irradiação Corporal Total/métodosRESUMO
PURPOSE: To investigate the role of the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) in the medium-mediated bystander effect for chromosomal aberrations induced by low-linear energy transfer (LET) X-rays and high-LET heavy ions in normal human fibroblast cells. MATERIALS AND METHODS: The recipient cells were treated for 12 h with conditioned medium, which was harvested from donor cells at 24 h after exposure to 10 Gy of soft X-rays (5 keV/microm) and 20Ne ions (437 keV/microm), followed by analyses of chromosome aberrations in recipient cells with premature chromosome condensation methods. To examine the role of DNA-PKcs and nitric oxide (NO), cells were treated with its inhibitor LY294002 (LY) and its scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (c-PTIO), respectively. RESULTS: Increased frequency of chromosome aberrations in recipient cells treated with conditioned medium from irradiated but not from un-irradiated donor cells was observed which was independent of radiation type. Bystander induction of chromosome aberrations in recipient cells was mitigated when donor cells were treated with LY before irradiation and with c-PTIO after irradiation, and was enhanced when recipient cells were treated with LY before treatment of recipient cells with conditioned medium from irradiated donor cells. CONCLUSION: Irradiated normal human cells secrete NO and other molecules which in turn transmit radiation signals to unirradiated bystander cells, leading to the induction of bystander chromosome aberrations partially repairable by DNA-PKcs-mediated DNA damage repair machinery, such as non-homologous end-joining repair pathways.
Assuntos
Efeito Espectador/efeitos da radiação , Aberrações Cromossômicas/efeitos da radiação , DNA/efeitos da radiação , Fibroblastos/efeitos da radiação , Íons Pesados/efeitos adversos , Transferência Linear de Energia , Proteínas Quinases/efeitos da radiação , Efeito Espectador/fisiologia , DNA/metabolismo , Relação Dose-Resposta à Radiação , Fibroblastos/citologia , Humanos , Óxido Nítrico/metabolismo , Proteínas Quinases/metabolismo , Fatores de Tempo , Raios XRESUMO
We have examined in vitro radiosensitivities and radioresponses to (60)Co gamma-rays irradiation in feline T-lymphocyte cell lines, FeT-J and FL-4. There seemed to be no significant difference in clonogenic survival between the two lines. The mean lethal dose for both was both 1.9 Gy, and surviving fraction at 2 Gy was 0.30 and 0.48 for FeT-J and FL-4 cells, respectively. However, TUNEL assay indicated much higher degrees of apoptosis induction in FeT-J cells (>40%) than in FL-4 cells (<10%) at 4 days after 15 Gy irradiation. Microscopic examination revealed a larger population of multi-nucleate cells in FL-4 cells (60.3%) than in FeT-J cells (16.0%) at 4 days after 15 Gy irradiation, suggesting that a larger ratio of mitotic catastrophe occurred in FL-4 cells. These results suggest that FeT-J is more likely to be induced into apoptosis and FL-4 is more likely to fall into mitotic catastrophe, and eventually necrosis; both of them showed a similar surviving fraction against gamma-rays. The results also indicate that FL-4 cells follow a process other than apoptosis to cell death, suggesting the presence of a regulatory mechanism that may control the relationship between mitotic catastrophe and apoptosis in feline T-lymphocytes.
Assuntos
Apoptose/efeitos da radiação , Sobrevivência Celular/efeitos da radiação , Linfócitos T/patologia , Linfócitos T/efeitos da radiação , Animais , Gatos , Linhagem Celular , Relação Dose-Resposta à Radiação , Raios gama , Doses de Radiação , Linfócitos T/classificaçãoRESUMO
Evidence has accumulated showing that ionizing radiations persistently perturb genomic stability and induce delayed reproductive death in the progeny of survivors; however, the linear energy transfer (LET) dependence of these inductions has not been fully characterized. We have investigated the cell killing effectiveness of gamma rays (0.2 keV/microm) and six different beams of heavy-ion particles with LETs ranging from 16.2 to 1610 keV/microm in normal human fibroblasts. First, irradiated confluent density-inhibited cultures were plated for primary colony formation, revealing that the relative biological effectiveness (RBE) based on the primary 10% survival dose peaked at 108 keV/microm and that the inactivation cross section increased proportionally up to 437 keV/microm. Second, cells harvested from primary colonies were plated for secondary colony formation, showing that delayed reproductive death occurred in a dose-dependent fashion. While the RBE based on the secondary 80% survival dose peaked at 108 keV/microm, very little difference in LET was observed in the RBE based on secondary survival at the primary 10% survival dose. Our present results indicate that delayed reproductive death arising only during secondary colony formation is independent of LET and is more likely to be dependent on initial damages having been fixed during primary colony formation.
Assuntos
Divisão Celular/efeitos da radiação , Sobrevivência Celular/efeitos da radiação , Fibroblastos/citologia , Fibroblastos/efeitos da radiação , Transferência Linear de Energia/fisiologia , Proliferação de Células/efeitos da radiação , Células Cultivadas , Relação Dose-Resposta à Radiação , Fibroblastos/fisiologia , Raios gama , Humanos , Transferência Linear de Energia/efeitos da radiação , Doses de Radiação , Eficiência Biológica RelativaRESUMO
Pharmacokinetics (PK) of probenecid including plasma probenecid concentrations, in vitro plasma protein binding properties, and in vivo PK parameters were determined in dogs. Probenecid concentrations were best determined by HPLC, which showed good linearity and good recovery with simple plasma preparation. The quantification limit of probenecid was approximately 50 ng/ml at S/N ratio = 3, by simple procedure with HCl and methanol treatment. Probenecid showed two types of binding characteristics, i.e., high-affinity with low-capacity and low-affinity with high-capacity binding. This result indicated 80-88% of probenecid was bound to plasma protein(s) at observed concentrations (< 80 microg/ml) in vivo at an intravenous dose of 20 mg/kg. Plasma probenecid concentration-time profile following i.v. administration in dogs showed biphasic decline and well fitted a two-compartment open model. The total body clearance was 0.34 +/- 0.04 ml/min/kg, volume of distribution at steady-state was 0.46 +/- 0.07 l/kg, elimination half-life was 18 +/- 6 hr, and mean residence time (MRT) was 23 +/- 6 hr. Since probenecid has been known as a potent inhibitor of renal tubular excretion of acidic drugs and highly binds to plasma proteins, our observation in relation to plasma protein binding and PK parameters will serve as the basic information concerning drug-drug interactions in dogs and in other mammalian species.
Assuntos
Proteínas Sanguíneas/metabolismo , Cães/metabolismo , Probenecid/metabolismo , Probenecid/farmacocinética , Uricosúricos/metabolismo , Uricosúricos/farmacocinética , Animais , Cães/sangue , Feminino , Meia-Vida , Ligação Proteica , Distribuição TecidualRESUMO
PURPOSE: To investigate positional effects of radiation with an energetic heavy-ion microbeam on germline cells using an experimental model metazoan Caenorhabditis elegans. MATERIALS AND METHODS: The germline cells were irradiated with raster-scanned broad beam or collimated microbeam of 220 MeV 12C5+ particles delivered from the azimuthally varying field (AVF) cyclotron, and subsequently observed for cell cycle arrest and apoptosis. RESULTS: Whole-body irradiation with the broad beam at the L4 larval stage arrested germ cell proliferation. When the tip region of the gonad arm was irradiated locally with the microbeam at the L4 stage, the same arrest was observed. When the microbeams were used to irradiate the pachytene region of the gonad arm, at a young gravid stage, radiation-induced apoptosis occurred in the gonad. In contrast, arrest and apoptosis were not induced in the non-irradiated neighboring region or the opposite gonad. Similar results were confirmed in the c-abl-1 (mammalian ortholog of cellular counterpart of Abelson murine leukemia virus) mutant that is hypersensitive to radiation-induced apoptosis. CONCLUSION: These results indicate that the microbeam irradiation is useful in characterizing tissue-specific, local biological response to radiation in organisms. DNA damage-induced cell cycle arrest and apoptosis were observed in locally irradiated regions, but there was little, if any, 'bystander effect' in the nematode.
Assuntos
Apoptose/efeitos da radiação , Ciclo Celular/efeitos da radiação , Células Germinativas/efeitos da radiação , Íons Pesados , Animais , Caenorhabditis elegans , Dano ao DNA , Células Germinativas/patologiaRESUMO
High linear energy transfer (LET) heavy charged particles have previously been applied clinically to human cancer radiotherapy because of their excellent physical properties of selective dose distribution and higher relative biological effectiveness (RBE) for human; however, such an approach has yet to be applied to cat patients. The present study investigates the biological effectiveness of low-LET gamma-rays (0.2 keV/micro m) compared to high-LET carbon ions (114 keV/micro m) in feline T- lymphocyte FeT-J cells. Clonogenic survival analysis revealed that the RBE value of carbon ions was 2.98 relative to a 10% survival dose (D(10)) by gamma-rays, and that the inactivation cross-section in cells exposed to gamma-rays and carbon ions was 0.023 and 38.9 micro m(2), respectively. Terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) analysis revealed that TUNEL-positive frequency in carbon-irradiation cells is higher than for gamma-irradiated cells against exposure to the same physical doses, but that very little difference in TUNEL-positive frequency is observed between cells exposed to the respective D(10) dose of gamma-rays. Our data thus indicate that carbon ions are more effective for cell killing than gamma-rays at the same physical doses, but kill cells to an extent that is comparable to gamma-rays at the same biological doses. Carbon ion radiotherapy is therefore a promising modality for cat patients.
Assuntos
Apoptose/efeitos dos fármacos , Carbono/farmacologia , Raios gama , Íons Pesados/efeitos adversos , Linfócitos T/citologia , Linfócitos T/efeitos da radiação , Animais , Gatos , Células CultivadasRESUMO
We have established a single cell irradiation system, which allows selected cells to be individually hit with defined number of heavy charged particles, using a collimated heavy-ion microbeam apparatus at JAERI-Takasaki. This system has been developed to study radiobiological processes in hit cells and bystander cells exposed to low dose and low dose-rate high-LET radiations, in ways that cannot be achieved using conventional broad-field exposures. Individual cultured cells grown in special dishes were irradiated in the atmosphere with a single or defined numbers of 18.3 MeV/amu 12C, 13.0 MeV/amu 20Ne, and 11.5 MeV/amu 40Ar ions. Targeting and irradiation of the cells were performed automatically at the on-line microscope of the microbeam apparatus according to the positional data of the target cells obtained at the off-line microscope before irradiation. The actual number of particle tracks that pass through cell nuclei was detected with prompt etching of the bottom of the cell dish made of ion track detector TNF-1 (modified CR-39), with alkaline-ethanol solution at 37 degrees C for 15-30 minutes. Using this system, separately inoculated Chinese hamster ovary cells, confluent normal human fibroblasts, and single plant cells (tobacco protoplasts) have been irradiated. These are the first studies in which single-ion direct hit effect and the bystander effect have been investigated using a high-LET heavy particle microbeam.