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1.
J Small Anim Pract ; 60(7): 430-437, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30790291

RESUMO

OBJECTIVES: To compare the progression-free survival of dogs with high-grade T-cell lymphoma treated with either a cyclophosphamide, doxorubicin, vincristine and prednisone-based or a modified mechlorethamine, vincristine, prednisone and procarbazine chemotherapy protocol. MATERIALS AND METHODS: In this retrospective study, cases were selected based on histologic or cytologic diagnosis of lymphoma, T-cell phenotype, hypercalcaemia, or both, and no previous chemotherapy for lymphoma. Treatment was not randomly allocated. RESULTS: Seventy-three dogs were included in this study: 50 in the cyclophosphamide, doxorubicin, vincristine and prednisone group and 23 in the mechlorethamine, vincristine, prednisone and procarbazine group. The median progression-free survival was 133 days for dogs in the cyclophosphamide, doxorubicin, vincristine and prednisone group and 97 days for dogs in the mechlorethamine, vincristine, prednisone and procarbazine group. When golden retrievers (n = 16) were evaluated -separately, progression-free survival was longer in the cyclophosphamide, doxorubicin, vincristine and prednisone versus mechlorethamine, vincristine, prednisone and procarbazine treatment group (median PFS 154 days versus 70.5 days, respectively). CLINICAL SIGNIFICANCE: The progression-free survival time for dogs with multi-centric T-cell lymphoma treated with a modified mechlorethamine, vincristine, prednisone and procarbazine protocol was similar to that of dogs treated with cyclophosphamide, doxorubicin, vincristine and prednisone. Further studies, including those evaluating golden retrievers separately, are needed to confirm these findings.


Assuntos
Hipercalcemia/veterinária , Linfoma/tratamento farmacológico , Linfoma/veterinária , Animais , Protocolos de Quimioterapia Combinada Antineoplásica , Asparaginase/uso terapêutico , Ciclofosfamida/uso terapêutico , Doenças do Cão , Cães , Doxorrubicina/uso terapêutico , Prednisona/uso terapêutico , Estudos Retrospectivos , Linfócitos T , Vincristina/uso terapêutico
2.
J Vet Intern Med ; 28(4): 1256-62, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24814522

RESUMO

BACKGROUND: The prognostic value of early magnetic resonance imaging (MRI) in dogs after traumatic brain injury (TBI) remains unclear. OBJECTIVES: Determine whether MRI findings are associated with prognosis after TBI in dogs. ANIMALS: Fifty client-owned dogs. METHODS: Retrospective study of dogs with TBI that underwent 1.5T MRI within 14 days after head trauma. MRI evaluators were blinded to the clinical presentation, and all images were scored based on an MRI grading system (Grade I [normal brain parenchyma] to Grade VI [bilateral lesions affecting the brainstem with or without any lesions of lesser grade]). Skull fractures, percentage of intraparenchymal lesions, degree of midline shift, and type of brain herniation were evaluated. MGCS was assessed at presentation. The presence of seizures was recorded. Outcome was assessed at 48 h (alive or dead) and at 3, 6, 12, and 24 months after TBI. RESULTS: Sixty-six percent of the dogs had abnormal MRI findings. MRI grade was negatively correlated (P < .001) with MGCS. A significant negative correlation of MRI grade, degree of midline shift, and percentage of intraparenchymal lesions with follow-up scores was identified. The MGCS was lower in dogs with brain herniation (P = .0191). Follow-up scores were significantly lower in dogs that had brain herniation or skull fractures. The possibility of having seizures was associated with higher percentage of intraparenchymal lesions (P = 0.0054) and 10% developed PTE. CONCLUSIONS AND CLINICAL IMPORTANCE: Significant associations exist between MRI findings and prognosis in dogs with TBI. MRI can help to predict prognosis in dogs with TBI.


Assuntos
Lesões Encefálicas/veterinária , Doenças do Cão/diagnóstico , Animais , Lesões Encefálicas/diagnóstico , Cães , Feminino , Escala de Coma de Glasgow/veterinária , Imageamento por Ressonância Magnética/veterinária , Masculino , Neuroimagem/veterinária , Prognóstico , Estudos Retrospectivos
3.
J Small Anim Pract ; 53(9): 526-30, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22835069

RESUMO

OBJECTIVES: To evaluate the prevalence of cluster seizures and status epilepticus in dogs with idiopathic epilepsy and determine risk factors for cluster seizure frequency, severity and patient outcome. METHODS: Retrospective review of medical records of 407 dogs with idiopathic epilepsy was made. Follow-up questionnaires were evaluated in cases with cluster seizures. RESULTS: Mean age at diagnosis of idiopathic epilepsy was 4 years. Cluster seizures were documented in 169 (41%) dogs. German shepherds and boxers were significantly (P=0·04 and 0·01, respectively) more likely to suffer from cluster seizures compared to Labrador retrievers. There was no association between the occurrence of status epilepticus and cluster seizures and frequency and severity of cluster seizures and status epilepticus episodes with age or breed. Intact males were twice as likely (P=0·003) than neutered dogs to suffer from cluster seizures. Intact females had significantly (P=0·007) more frequent cluster seizures than neutered dogs. The median survival time for all dogs with cluster seizures was 95 months. Significantly (P=0·03) more dogs with frequent cluster seizures were euthanased because of the cluster seizures. CLINICAL SIGNIFICANCE: There was a high prevalence of cluster seizures in dogs with idiopathic epilepsy. Neutering status appears to influence cluster seizure occurrence with intact females more likely to experience more frequent episodes. Euthanasia is associated with frequency of cluster seizure episodes.


Assuntos
Doenças do Cão/epidemiologia , Epilepsias Mioclônicas/veterinária , Convulsões/veterinária , Estado Epiléptico/veterinária , Fatores Etários , Animais , Anticonvulsivantes/uso terapêutico , Doenças do Cão/tratamento farmacológico , Doenças do Cão/etiologia , Cães , Epilepsias Mioclônicas/complicações , Epilepsias Mioclônicas/tratamento farmacológico , Epilepsias Mioclônicas/epidemiologia , Feminino , Masculino , Linhagem , Prevalência , Estudos Retrospectivos , Fatores de Risco , Convulsões/complicações , Convulsões/tratamento farmacológico , Convulsões/epidemiologia , Índice de Gravidade de Doença , Fatores Sexuais , Estado Epiléptico/tratamento farmacológico , Estado Epiléptico/epidemiologia , Estado Epiléptico/etiologia , Resultado do Tratamento
4.
Vet Pathol ; 48(6): 1075-84, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21245281

RESUMO

The pathogenesis and virulence of Bovine enterovirus-1 (BEV-1) in cattle is largely unknown. Reports concerning its virulence suggest that there might be an association between BEV-1 infections and a range of diseases in cattle that vary from respiratory to enteric to reproductive disease and infertility. In the current study, the pathogenesis associated with acute infection of BEV-1 in calves experimentally inoculated with the Oklahoma isolate of BEV-1 was described. Although interpretation of the study was limited by lack of an effective control group, results suggest that an association between inoculation of BEV-1, virus localization, and the potential development of lesions in the brain and heart probably exists. In the experiment, BEV-1 virus localized to the terminal ileum, ileocecal and cecocolonic junctions, spiral colon, and ileocecal lymph nodes; BEV-1 virus was detected in the cytoplasm of enterocytes, lamina propria macrophages, endothelium, neurons of the submucosal and myenteric plexi, and lymphocytes of the submucosal lymphoid tissue. Although no clinical signs were noted following acute infection, BEV-1 was localized in the cerebellar white matter of a calf with encephalitis and in the heart of another calf with coronary arteritis. The current study suggests that the BEV-1 isolate is infectious to young calves and that BEV-1 potentially can have a similar pathogenesis to that observed in natural or experimental enterovirus infections in other species.


Assuntos
Anticorpos Antivirais/sangue , Doenças dos Bovinos/virologia , Encefalite Viral/veterinária , Infecções por Enterovirus/veterinária , Enterovirus Bovino/patogenicidade , Animais , Bovinos , Doenças dos Bovinos/patologia , Encefalite Viral/patologia , Encefalite Viral/virologia , Infecções por Enterovirus/patologia , Infecções por Enterovirus/virologia , Enterovirus Bovino/genética , Enterovirus Bovino/imunologia , Enterovirus Bovino/isolamento & purificação , Fezes/virologia , Feminino , Hibridização In Situ/veterinária , Masculino , Oklahoma , Ovinos , Virulência
5.
Vet Comp Oncol ; 7(1): 38-44, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19222829

RESUMO

Forty-one dogs with resistant lymphoma were treated with a modified MOPP (mechlorethamine, vincristine, procarbazine and prednisone) protocol (MPP [mechlorethamine, procarbazine and prednisone] administered on a 21-day cycle, shortened from the 28-day MOPP cycle). The overall response rate to MPP was 34% for a median of 56 days (95% confidence interval 30-238). Seventeen percent of dogs had a complete response for a median duration of 238 days, 17% had a partial response for a median of 56 days and 32% had stable disease for a median of 24 days. Histological grade or cell morphology on cytology was associated with response. Minimal toxicity was observed with the MPP protocol, suggesting that further dose intensification or addition of another chemotherapeutic agent would be possible.


Assuntos
Antineoplásicos/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Doenças do Cão/tratamento farmacológico , Resistencia a Medicamentos Antineoplásicos , Linfoma/veterinária , Animais , Antineoplásicos/efeitos adversos , Antineoplásicos Alquilantes/administração & dosagem , Antineoplásicos Alquilantes/efeitos adversos , Antineoplásicos Hormonais/administração & dosagem , Antineoplásicos Hormonais/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Doenças do Cão/sangue , Doenças do Cão/patologia , Cães , Feminino , Georgia , Linfoma/sangue , Linfoma/tratamento farmacológico , Linfoma/patologia , Masculino , Mecloretamina/administração & dosagem , Mecloretamina/efeitos adversos , Prednisona/administração & dosagem , Prednisona/efeitos adversos , Procarbazina/administração & dosagem , Procarbazina/efeitos adversos , Indução de Remissão/métodos , Resultado do Tratamento
6.
J Vet Intern Med ; 23(1): 146-51, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19175733

RESUMO

BACKGROUND: Tumor proliferation in human intracranial meningiomas can be defined by the reactivity of the monoclonal antibody MIB-1 to the Ki-67 antigen. Vascular endothelial growth factor (VEGF), a pro-angiogenic factor, is a predictive marker for survival of dogs with intracranial meningiomas. HYPOTHESIS: Ki-67 is expressed in canine intracranial meningiomas and is associated with VEGF expression. Ki-67 expression is a prognostic marker for patient outcome. ANIMALS: Seventy client-owned dogs with WHO grade I intracranial meningiomas. METHODS: Retrospective study assessing the degree of immunostaining for Ki-67 by MIB-1 and VEGF expression in intracranial meningioma tissue from dogs. MIB-1 Labeling Index (LI) was calculated with Image J NIH-software. Extent, intensity, and distribution of VEGF-expression was assessed semiquantitatively. Cross tabulations with Fisher's exact tests and nonparametric Spearman's rank correlations were performed to identify associations between VEGF expression and MIB-1 LI. Fifteen dogs underwent postsurgical radiotherapy and were included in survival analysis. The effect of MIB-1 LI on survival was examined by Kaplan-Meier and Cox proportional hazards regression procedures. RESULTS: Ki-67 staining was positive in 91% (64/70) and VEGF expression was detected in 96% (67/70). There was no significant association between VEGF expression and MIB-1 LI. MIB-1 LI was not associated with survival. CONCLUSIONS AND CLINICAL IMPORTANCE: MIB-1 antibody can be used to document cell proliferation in intracranial meningiomas in dogs, but does not predict outcome. No association between VEGF as a marker of angiogenesis and tumor proliferation was found. Angiogenesis might be a more important predictor of meningioma activity in dogs than is Ki-67.


Assuntos
Doenças do Cão/metabolismo , Regulação Neoplásica da Expressão Gênica/fisiologia , Antígeno Ki-67/metabolismo , Meningioma/veterinária , Fator A de Crescimento do Endotélio Vascular/metabolismo , Animais , Cães , Antígeno Ki-67/genética , Fator A de Crescimento do Endotélio Vascular/genética
7.
Int J Toxicol ; 24(1): 35-41, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15981738

RESUMO

Rat tissue:air and blood:air partition coefficients (PCs) for octane, nonane, decane, undecane, and dodecane (n-C8 to n-C12 n-alkanes) were determined by vial equilibration. The blood:air PC values for n-C8 to n-C12 were 3.1, 5.8, 8.1, 20.4, and 24.6, respectively. The lipid solubility of n-alkanes increases with carbon length, suggesting that lipid solubility is an important determinant in describing n-alkane blood:air PC values. The muscle:blood, liver: blood, brain:blood, and fat:blood PC values were octane (1.0, 1.9, 1.4, and 247), nonane (0.8, 1.9, 3.8, and 274), decane (0.9, 2.0, 4.8, and 328), undecane (0.7, 1.5, 1.7, and 529), and dodecane (1.2, 1.9, 19.8, and 671), respectively. The tissue:blood PC values were greatest in fat and the least in muscle. The brain:air PC value for undecane was inconsistent with other n-alkane values. Using the measured partition coefficient values of these n-alkanes, linear regression was used to predict tissue (except brain) and blood:air partition coefficient values for larger n-alkanes, tridecane, tetradecane, pentadecane, hexadecane, and heptadecane (n-C13 to n-C17). Good agreement between measured and predicted tissue:air and blood:air partition coefficient values for n-C8 to n-Cl2 offer confidence in the partition coefficient predictions for longer chain n-alkanes.


Assuntos
Alcanos/química , Análise Química do Sangue , Distribuição Tecidual , Alcanos/análise , Animais , Técnicas In Vitro , Masculino , Modelos Biológicos , Ratos , Ratos Sprague-Dawley , Solubilidade , Volatilização
8.
Inhal Toxicol ; 16(11-12): 771-83, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-16036747

RESUMO

Decane, a 10-carbon n-alkane and one of the highest vapor phase constituents of jet propellent-8 (JP-8), was selected to represent the semivolatile fraction for the initial development of a physiologically based pharmacokinetic (PBPK) model for JP-8. Rats were exposed to decane vapors at time-weighted average concentrations of 1200, 781, or 273 ppm in a 32-L Leach chamber for 4 h. Time-course samples for 1200 ppm and end-of-exposure samples for 781 and 273 ppm decane exposures were collected from blood, brain, liver, fat, bone marrow, lung, skin, and spleen. The pharmacokinetics of decane could not be described by flow-limited assumptions and measured in vitro tissue/air partition coefficients. A refined PBPK model for decane was then developed using flow-limited (liver and lung) and diffusion-limited (brain, bone marrow, fat, skin, and spleen) equations to describe the uptake and clearance of decane in the blood and tissues. Partition coefficient values for blood/air and tissue/blood were estimated by fitting end-of-exposure pharmacokinetic data and assumed to reflect the available decane for rapid exchange with blood. A portion of decane is speculated to be sequestered in "deep" pools in the body, unavailable for rapid exchange with blood. PBPK model predictions were adequate in describing the tissues and blood kinetics. For model validation, the refined PBPK model for decane had mixed successes at predicting tissue and blood concentrations for lower concentrations of decane vapor, suggesting that further improvements in the model may be necessary to extrapolate to lower concentrations.


Assuntos
Alcanos/farmacocinética , Alcanos/administração & dosagem , Alcanos/química , Animais , Câmaras de Exposição Atmosférica , Volume Sanguíneo/efeitos dos fármacos , Barreira Alveolocapilar , Débito Cardíaco/efeitos dos fármacos , Cromatografia Gasosa , Simulação por Computador , Hemodinâmica/efeitos dos fármacos , Exposição por Inalação , Masculino , Modelos Biológicos , Ratos , Ratos Endogâmicos F344 , Fluxo Sanguíneo Regional/efeitos dos fármacos , Reprodutibilidade dos Testes , Testes de Função Respiratória , Distribuição Tecidual
9.
Toxicol Sci ; 53(2): 173-84, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10696765

RESUMO

Phthalate esters are ubiquitous, low-level environmental contaminants that induce testicular toxicity in laboratory animals. The diester is rapidly metabolized in the gut to the monoester, which causes the testicular toxicity. Several physiologically based pharmacokinetic (PBPK) model structures have been evaluated for di(2-ethylhexyl) phthalate (DEHP) and mono(2-ethylhexyl) phthalate (MEHP). The objective of this study was to test these PBPK models for a less lipophilic phthalate diester, di(n-butyl) phthalate (DBP), and monoester, mono(n-butyl) phthalate (MBP). Alternate models describing enterohepatic circulation, diffusion-limitation, tissue pH gradients (pH trapping), and a simpler, flow-limited model were evaluated. A combined diffusion-limited and pH trapping model was also tested. MBP tissue:blood partition coefficients were similar when determined either experimentally by a nonvolatile, vial equilibration technique or algorithmically. All other parameters were obtained from the literature or estimated from MBP blood concentrations following intravenous or oral exposure to DBP or MBP. A flow-limited model was unable to predict MBP blood levels, whereas each alternative model had statistically better predictions. The combined diffusion-limited and pH trapping model was the best overall, having the highest log-likelihood function value. This result is consistent with a previous finding that the pH trapping model was the best model for describing DEHP and MEHP blood dosimetry, though it was necessary to extend the model to include diffusion-limitation. The application of the pH trapping model is a step toward developing a generic model structure for all phthalate esters, though more work is required before a generic structure can be identified with confidence. Development of a PBPK model structure applicable to all phthalate esters would support more realistic assessments of risk to human health from exposure to one or more members of this class of compounds.


Assuntos
Dibutilftalato/farmacocinética , Ácidos Ftálicos/farmacocinética , Administração Oral , Animais , Dibutilftalato/análise , Poluentes Ambientais/sangue , Poluentes Ambientais/farmacocinética , Injeções Intravenosas , Masculino , Modelos Biológicos , Ácidos Ftálicos/sangue , Ratos , Ratos Sprague-Dawley , Ratos Wistar
10.
Toxicol Sci ; 49(2): 172-85, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10416263

RESUMO

Di(2-ethylhexyl) phthalate (DEHP), a commercially important plasticizer, induces testicular toxicity in laboratory animals at high doses. After oral exposure, most of the DEHP is rapidly metabolized in the gut to mono(2-ethylhexyl) phthalate (MEHP), which is the active metabolite for induction of testicular toxicity. To quantify the testes dose of MEHP with various routes of exposure and dose levels, we developed a physiologically based pharmacokinetic (PBPK) model for DEHP and MEHP in rats. Tissue:blood partition coefficients for DEHP were estimated from the n-octanol: water partition coefficient, while partition coefficients for MEHP were determined experimentally using a vial equilibration technique. All other parameters were either found in the literature or estimated from blood or tissue levels following oral or intravenous exposure to DEHP or MEHP. A flow-limited model failed to adequately simulate the available data. Alternative plausible mechanisms were explored, including diffusion-limited membrane transport, enterohepatic circulation, and MEHP ionization (pH-trapping model). In the pH-trapping model, only nonionized MEHP is free to become partitioned into the tissues, where it is equilibrated and trapped as ionized MEHP until it is deionized and released. All three alternative models significantly improved predictions of DEHP and MEHP blood concentrations over the flow-limited model predictions. The pH-trapping model gave the best predictions with the largest value of the log likelihood function. Predicted MEHP blood and testes concentrations were compared to measured concentrations in juvenile rats to validate the pH-trapping model. Thus, MEHP ionization may be an important mechanism of MEHP blood and testes disposition in rats.


Assuntos
Ácidos Ftálicos/sangue , Ácidos Ftálicos/farmacocinética , Plastificantes/metabolismo , Testículo/metabolismo , Animais , Difusão , Circulação Êntero-Hepática/fisiologia , Concentração de Íons de Hidrogênio , Masculino , Modelos Biológicos , Ratos , Ratos Sprague-Dawley , Solubilidade
11.
Science ; 283(5401): 532-4, 1999 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-9915699

RESUMO

The origin of new morphological characters is a long-standing problem in evolutionary biology. Novelties arise through changes in development, but the nature of these changes is largely unknown. In butterflies, eyespots have evolved as new pattern elements that develop from special organizers called foci. Formation of these foci is associated with novel expression patterns of the Hedgehog signaling protein, its receptor Patched, the transcription factor Cubitus interruptus, and the engrailed target gene that break the conserved compartmental restrictions on this regulatory circuit in insect wings. Redeployment of preexisting regulatory circuits may be a general mechanism underlying the evolution of novelties.


Assuntos
Borboletas/genética , Proteínas de Drosophila , Regulação da Expressão Gênica , Proteínas de Insetos/genética , Asas de Animais/crescimento & desenvolvimento , Animais , Evolução Biológica , Padronização Corporal , Borboletas/anatomia & histologia , Borboletas/crescimento & desenvolvimento , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/fisiologia , Genes de Insetos , Proteínas Hedgehog , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/fisiologia , Proteínas de Insetos/fisiologia , Proteínas de Membrana/genética , Proteínas de Membrana/fisiologia , Pigmentação , Receptores de Superfície Celular , Transdução de Sinais , Fatores de Transcrição/genética , Fatores de Transcrição/fisiologia , Transcrição Gênica , Asas de Animais/anatomia & histologia , Asas de Animais/metabolismo
12.
Mol Cell Biol ; 18(7): 3752-61, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9632758

RESUMO

Previous in vitro studies have shown that initiation of transcription of ribosomal DNA (rDNA) in the yeast Saccharomyces cerevisiae involves an interaction of upstream activation factor (UAF) with the upstream element of the promoter, forming a stable UAF-template complex; together with TATA-binding protein (TBP), UAF then recruits an essential factor, core factor (CF), to the promoter, forming a stable preinitiation complex. TBP interacts with both UAF and CF in vitro. In addition, a subunit of UAF, Rrn9p, interacts with TBP in vitro and in the two-hybrid system, suggesting the possible importance of this interaction for UAF function. Using the yeast two-hybrid system, we have identified three mutations in RRN9 that abolish the interaction of Rrn9p with TBP without affecting its interaction with Rrn10p, another subunit of UAF. Yeast cells containing any one of these individual mutations, L110S, L269P, or L274Q, did not show any growth defects. However, cells containing a combination of L110S with one of the other two mutations showed a temperature-sensitive phenotype, and this phenotype was suppressed by fusing the mutant genes to SPT15, which encodes TBP. In addition, another mutation (F186S), which disrupts both Rrn9p-TBP and Rrn9p-Rrn10p interactions in the two-hybrid system, abolished UAF function in vivo, and this mutational defect was suppressed by fusion of the mutant gene to SPT15 combined with overexpression of Rrn10p. These experiments demonstrate that the interaction of UAF with TBP, which is presumably achieved by the interaction of Rrn9p with TBP, is indeed important for high-level transcription of rDNA by RNA polymerase I in vivo.


Assuntos
DNA Ribossômico/genética , Proteínas de Ligação a DNA/metabolismo , RNA Polimerase I/metabolismo , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Fatores de Transcrição/metabolismo , Ativação Transcricional , Fusão Gênica Artificial , Sítios de Ligação , DNA Fúngico/genética , Proteínas de Ligação a DNA/genética , Genes Fúngicos , Mutagênese , Hibridização de Ácido Nucleico , RNA Polimerase II/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/metabolismo , Proteína de Ligação a TATA-Box , Transativadores/metabolismo , Fatores de Transcrição/genética
13.
Development ; 125(12): 2303-13, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9584129

RESUMO

The eastern tiger swallowtail butterfly Papilio glaucus shows a striking example of Batesian mimicry. In this species, females are either wild type (yellow and black) or melanic (where most of the yellow colour is replaced by black). In order to understand how these different colour patterns are regulated, we examined the temporal order of wing pigment synthesis via precursor incorporation studies, enzyme assays, and in situ hybridisation to mRNA encoding a key enzyme, dopa decarboxylase. We show that dopa decarboxylase provides dopamine to both of the two major colour pigments, papiliochrome (yellow) and melanin (black). Interestingly, however, dopa decarboxylase activity is spatially and temporally regulated, being utilised early in presumptive yellow tissues and later in black. Further, in melanic females, both dopa decarboxylase activity and early papiliochrome synthesis are suppressed in the central forewing and this normally yellow area is later melanised. These results show that the regulation of enzyme synthesis observed in the yellow/black pattern of a single wing, is similar to that involved in melanism. We infer that dopa decarboxylase activity must be regulated in concert with downstream enzymes of either the melanin and/or the papiliochrome specific pathways, forming part of a developmental switch between yellow or black. This modification of multiple enzyme activities in concert is consistent with a model of melanisation involving coordinate regulation of the underlying synthetic pathways by a single Y-linked (female) factor.


Assuntos
Borboletas/enzimologia , Dopa Descarboxilase/genética , Regulação Enzimológica da Expressão Gênica , Cinurenina/análogos & derivados , Melaninas/biossíntese , Pigmentos Biológicos/biossíntese , Animais , Borboletas/genética , Borboletas/crescimento & desenvolvimento , Dopa Descarboxilase/metabolismo , Dopamina/metabolismo , Feminino , Cinurenina/biossíntese , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Asas de Animais/enzimologia
14.
15.
Nature ; 384(6606): 236-42, 1996 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-12809139

RESUMO

The developmental and genetic bases for the formation, plasticity and diversity of eyespot patterns in butterflies are examined. Eyespot pattern mutants, regulatory gene expression, and transplants of the eyespot developmental organizer demonstrate that eyespot position, number, size and colour are determined progressively in a developmental pathway largely uncoupled from those regulating other wing-pattern elements and body structures. Species comparisons and selection experiments suggest that the evolution of eyespot patterns can occur rapidly through modulation of different stages of this pathway, and requires only single, or very few, changes in regulatory genes.


Assuntos
Evolução Biológica , Borboletas/crescimento & desenvolvimento , Borboletas/genética , Genes de Insetos , Asas de Animais/crescimento & desenvolvimento , Adaptação Biológica , Animais , Padronização Corporal , Borboletas/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Genes Reguladores , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Mutação , Fenótipo , Pigmentação , Estações do Ano , Transdução de Sinais , Especificidade da Espécie , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Asas de Animais/anatomia & histologia , Asas de Animais/metabolismo , Asas de Animais/transplante
16.
Genes Dev ; 10(20): 2551-63, 1996 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-8895657

RESUMO

Transcription of Saccharomyces cerevisiae rDNA by RNA polymerase I involves at least two transcription factors characterized previously: upstream activation factor (UAF) consisting of Rrn5p, Rrn9p, Rrn10p, and two more uncharacterized proteins; and core factor (CF) consisting of Rrn6p, Rrn7p, and Rrn11p. UAF interacts directly with an upstream element of the promoter and mediates its stimulatory function, and CF subsequently joins a stable preinitiation complex. The TATA-binding protein (TBP) has been known to be involved in transcription by all three nuclear RNA polymerases. We found that TBP interacts specifically with both UAF and CF, the interaction with UAF being stronger than that with CF. Using extracts from a TBP (I143N) mutant, it was shown that TBP is required for stimulation of transcription mediated by the upstream element, but not for basal transcription directed by a template without the upstream element. By template competition experiments, it was shown that TBP is required for UAF-dependent recruitment of CF to the rDNA promoter, explaining the TBP requirement for stimulatory activity of the upstream element. We also studied protein-protein interactions and found specific interactions of TBP with Rrn6p and with Rrn9p both in vitro and in the yeast two-hybrid system in vivo. Thus, these two interactions may be involved in the interactions of TBP with CF and UAF, respectively, contributing to the recruitment of CF to the rDNA promoter. Additionally, we observed an interaction between Rrn9p and Rrn7p both in vitro and in the two-hybrid system; thus, this interaction might also contribute to the recruitment of CF.


Assuntos
DNA Ribossômico , Proteínas de Ligação a DNA/metabolismo , Proteínas Fúngicas/metabolismo , Proteínas Pol1 do Complexo de Iniciação de Transcrição , RNA Polimerase I/metabolismo , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição/metabolismo , Transcrição Gênica , Regiões Promotoras Genéticas , Proteína de Ligação a TATA-Box , Moldes Genéticos
17.
Genes Dev ; 10(7): 887-903, 1996 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-8846924

RESUMO

Like most eukaryotic rDNA promoters, the promoter for rDNA in Saccharomyces cerevisiae consists of two elements: a core element, which is essential, and an upstream element, which is not essential but is required for a high level of transcription. We have demonstrated that stimulation of transcription by the upstream element is mediated by a multiprotein transcription factor, UAF (upstream activation factor) which contains three proteins encoded by RRN5, RRN9, and RRN10 genes, respectively, and probably two additional uncharacterized proteins. The three genes were originally defined by mutants that show specific reduction in the transcription of rDNA. These genes were cloned and characterized. Epitope tagging of RRN5 (or RRN9), combined with immunoaffinity purification was used to purify UAF, which complemented all three (rrn5, rrn9, and rrn10) mutant extracts. Using rrn10 mutant extracts, a large stimulation by UAF was demonstrated for template containing both the core element and the upstream element but not for a template lacking the upstream element. In the absence of UAF, the mutant extracts showed the same weak transcriptional activity regardless of the presence or absence of the upstream element. We have also demonstrated that UAF alone makes a stable complex with the rDNA template, committing that template to transcription. Conversely, no such template commitment was observed with rrn10 extracts without UAF. By using a series of deletion templates, we have found that the region necessary for the stable binding of UAF corresponds roughly to the upstream element defined previously based on its ability to stimulate rDNA transcription. Differences between the yeast UAF and the previously studied metazoan UBF are discussed.


Assuntos
DNA Ribossômico , Proteínas de Ligação a DNA/metabolismo , Regiões Promotoras Genéticas , RNA Polimerase I/metabolismo , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Fatores de Transcrição/metabolismo , Transcrição Gênica , Sequência de Aminoácidos , Sequência de Bases , Sistema Livre de Células , Clonagem Molecular , Cruzamentos Genéticos , Proteínas de Ligação a DNA/isolamento & purificação , Genes Fúngicos , Teste de Complementação Genética , Dados de Sequência Molecular , Mutação , RNA Ribossômico/biossíntese , Análise de Sequência de DNA , Deleção de Sequência , Moldes Genéticos , Fatores de Transcrição/isolamento & purificação
18.
J Clin Forensic Med ; 2(1): 41-4, 1995 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15335665

RESUMO

This report describes the use of a salivary alcohol measurement device in clinical forensic medicine, and concludes that it may be of use in assisting the diagnosis or the assessment of patients in the custodial setting.

19.
Genes Dev ; 8(19): 2349-62, 1994 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-7958901

RESUMO

Previously, we have isolated mutants of Saccharomyces cerevisiae primarily defective in the transcription of 35S rRNA genes by RNA polymerase I and have identified a number of genes (RRN genes) involved in this process. We have now cloned the RRN6 and RRN7 genes, determined their nucleotide sequences, and found that they encode proteins of calculated molecular weights of 102,000 and 60,300, respectively. Extracts prepared from rrn6 and rrn7 mutants were defective in in vitro transcription of rDNA templates. We used extracts from strains containing epitope-tagged wild-type Rrn6 or Rrn7 proteins to purify protein components that could complement these mutant extracts. By use of immunoaffinity purification combined with biochemical fractionation, we obtained a highly purified preparation (Rrn6/7 complex), which consisted of Rrn6p, Rrn7p, and another protein with an apparent molecular weight of 66,000, but which did not contain the TATA-binding protein (TBP). This complex complemented both rrn6 and rrn7 mutant extracts. Template commitment experiments carried out with this purified Rrn6/7 complex and with rrn6 mutant extracts have demonstrated that the Rrn6/7 complex does not bind stably to the rDNA template by itself, but its binding is dependent on the initial binding of some other factor(s) and that the Rrn6/7 complex is required for the formation of a transcription-competent preinitiation complex. These observations are discussed in comparison to in vitro rDNA transcription systems from higher eukaryotes.


Assuntos
DNA Ribossômico/genética , Proteínas Fúngicas/genética , Proteínas Pol1 do Complexo de Iniciação de Transcrição , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição/genética , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , DNA Fúngico/genética , Proteínas Fúngicas/isolamento & purificação , Proteínas Fúngicas/metabolismo , Deleção de Genes , Genes Fúngicos , Teste de Complementação Genética , Dados de Sequência Molecular , Mutação , RNA Polimerase I/metabolismo , Fatores de Transcrição/isolamento & purificação , Fatores de Transcrição/metabolismo , Transcrição Gênica
20.
J Clin Forensic Med ; 1(2): 93-6, 1994 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16371274

RESUMO

OBJECTIVE: to identify the prevalence of high-risk factors for infection with Human Immunodeficiency Virus (HIV) in individuals examined in clinical forensic medical practice and to determine opinions and attitudes about HIV in this patient group. DESIGN: Anonymised questionnaire completed by consecutive individuals seen in clinical forensic medical practice. SETTING: Police stations in London attended by Group IV forensic medical examiners. SUBJECTS: 518 individuals examined in police stations (including prisoners and suspects, those detained in police custody, police officers and victims of crime). RESULTS: 164 (31.7%) individuals did not respond to the questionnaire because of: 1) refusal (12.6%) 2) inability because of drugs and/or alcohol (11.4%) 3) mental illness/disorder (4.2%) or 4) language difficulties (3.5%). 28.4% of the respondents were in at least one of the 'high-risk' categories for HIV infection. 26.5% were intravenous drug misusers; 15% were prostitutes; 9.8% (or their sexual partners) had lived in Central or East Africa since 1977; 5.9% were male homosexuals and 0.5% were haemophiliacs. 5.1% were infected with HIV or had Acquired Immunodeficiency Syndrome (AIDS). Only 28.8% of individuals always used condoms in short-term sexual relationships. 44.4% of respondents believed that everyone should be tested for HIV. CONCLUSION: Over one-quarter of the respondents were in higher-risk groups for infection with HIV. Almost one-third could or would not respond. It is concluded that it is not possible to identify by questionnaire, individuals at higher risk of HIV infection in forensic medical practice. This reinforces the necessity of observing good clinical practice to reduce contamination risks in this work environment. It is clear that education about risks for HIV infection is still much needed.

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