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1.
Lymphology ; 55(2): 65-69, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36170580

RESUMO

Plastic bronchitis, more appropriately termed chyloptysis, is a rare and potentially fatal condition caused by chylous coating of the airways. These cast coating can dislodge and become an obstructive mass in the patient's airway, necessitating rapid intervention. PB is well described to occur following single ventricle physiology heart disease corrective procedures, particularly following Fontan procedures. It is less commonly seen in traumatic settings. We present the youngest known case of a traumatic injury induced plastic bronchitis. A 19-year-old man was involved in a motor vehicle accident with airbag deployment. The airbags struck him in the chest; however, the patient felt well at the time and did not seek medical attention. Several months later the patient began coughing up milky white masses identified as casts. He was initially diagnosed with asthma but did not respond to therapy. He ultimately was found to have evidence of thoracic duct injury. Options for therapy were discussed, including possible thoracic duct ligation. The patient opted to continue a lowfat diet and has remained cast free. This case highlights the importance of considering plastic bronchitis in patients with cast production and a history of trauma to the chest.


Assuntos
Bronquite , Técnica de Fontan , Adulto , Bronquite/diagnóstico , Bronquite/etiologia , Bronquite/terapia , Técnica de Fontan/efeitos adversos , Humanos , Masculino , Veículos Automotores , Plásticos , Ducto Torácico/cirurgia , Adulto Jovem
2.
Ann Surg Oncol ; 27(Suppl 3): 983, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32699930

RESUMO

C.R. Farley and M.C. Perez contributed equally to this publication and are co-first authors. J.S. Zager and M.C. Lowe contributed equally to this publication and are co-corresponding authors.

3.
Ann Surg Oncol ; 27(6): 1978-1985, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32103415

RESUMO

INTRODUCTION: The eighth edition of the American Joint Committee on Cancer (AJCC8) Staging Manual provides important information for staging and prognostication; however, survival estimates for patients with Stage I-III Merkel cell carcinoma (MCC), a rare disease, may be as practical using data from large-volume centers as that collated for the AJCC analysis. As such, we compared our institutional outcomes to AJCC8. METHODS: Patients who presented from 2005 to 2017 with MCC to two high-volume centers were included. Demographics, clinicopathologic characteristics, survival and recurrence data were compiled, and outcomes compared to AJCC8. RESULTS: A total of 409 patients were included. Median age was 75 (range 29-98) years, and 68% were male. Median follow-up was 16 months (0-157). Five-year overall survival (OS) was 70%; 5-year disease-specific survival (DSS) was 84%. When stratified by extent of disease, 5-year OS was higher for patients with local disease compared to those with nodal disease (72.6% vs 62.7%, p=0.005). Similarly, patients with local disease had higher 5-year DSS than those with nodal disease (90.1% vs 76.8%, p=0.002). Five-year recurrence-free survival was 59.2% for all patients, 65.0% for local disease and 48.3% for nodal disease (p=0.033). CONCLUSIONS: Here, MCC patients with local or nodal disease have substantially higher OS rates than predicted in AJCC8 (5-year: 72.6% vs 50.6%; 62.7% vs 35.4%, respectively). Importantly, 5-year DSS was significantly better than the OS rates reported presently and in AJCC8. As clinicians and patients rely on AJCC to accurately prognosticate and guide treatment decisions, these estimates should be reassessed and updated to more accurately predict survival outcomes.


Assuntos
Carcinoma de Célula de Merkel/mortalidade , Carcinoma de Célula de Merkel/patologia , Estadiamento de Neoplasias , Neoplasias Cutâneas/mortalidade , Neoplasias Cutâneas/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Análise de Sobrevida , Fatores de Tempo , Estados Unidos/epidemiologia
4.
Am J Transplant ; 17(9): 2285-2299, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28502128

RESUMO

Recently, newer therapies have been designed to more specifically target rejection in an effort to improve efficacy and limit unwanted toxicity. Belatacept, a CD28-CD80/86 specific reagent, is associated with superior patient survival and graft function compared with traditional therapy, but its adoption as a mainstay immunosuppressive therapy has been tempered by increased rejection rates. It is essential that the underlying mechanisms associated with this rejection be elucidated before belatacept is more widely used. To that end, we designed a study in a nonhuman primate kidney transplant model where animals were treated with either a belatacept- or a tacrolimus-based immunosuppressive regimen. Interestingly, we found that elevated pretransplant frequencies of CD28+ CD8+ TEMRA cells are associated with rejection on belatacept but not tacrolimus treatment. Further analysis showed that the CD28+ CD8+ TEMRA cells rapidly lose CD28 expression after transplant in those animals that go on to reject with the allograft infiltrate being predominantly CD28- . These data suggest that CD28+ memory T cells may be resistant to belatacept, capable of further differentiation including loss of CD28 expression while maintaining effector function. The unique signaling requirements of CD28+ memory T cells provide opportunities for the development of targeted therapies, which may synergize with belatacept to prevent costimulation-independent rejection.


Assuntos
Abatacepte/farmacologia , Antígenos CD28/imunologia , Linfócitos T CD8-Positivos/imunologia , Resistência a Medicamentos/imunologia , Rejeição de Enxerto/imunologia , Memória Imunológica/imunologia , Transplante de Rim/efeitos adversos , Animais , Antígenos CD28/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Taxa de Filtração Glomerular , Rejeição de Enxerto/etiologia , Rejeição de Enxerto/patologia , Sobrevivência de Enxerto , Imunossupressores/farmacologia , Falência Renal Crônica/cirurgia , Testes de Função Renal , Macaca mulatta , Complicações Pós-Operatórias
5.
Am J Transplant ; 15(5): 1241-52, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25702898

RESUMO

Islet xenotransplantation is a potential treatment for diabetes without the limitations of tissue availability. Although successful experimentally, early islet loss remains substantial and attributed to an instant blood-mediated inflammatory reaction (IBMIR). This syndrome of islet destruction has been incompletely defined and characterization in pig-to-primate models has been hampered by logistical and statistical limitations of large animal studies. To further investigate IBMIR, we developed a novel in vivo dual islet transplant model to precisely characterize IBMIR as proof-of-concept that this model can serve to properly control experiments comparing modified xenoislet preparations. WT and α1,3-galactosyltransferase knockout (GTKO) neonatal porcine islets were studied in nonimmunosuppressed rhesus macaques. Inert polyethylene microspheres served as a control for the effects of portal embolization. Digital analysis of immunohistochemistry targeting IBMIR mediators was performed at 1 and 24 h after intraportal islet infusion. Early findings observed in transplanted islets include complement and antibody deposition, and infiltration by neutrophils, macrophages and platelets. Insulin, complement, antibody, neutrophils, macrophages and platelets were similar between GTKO and WT islets, with increasing macrophage infiltration at 24 h in both phenotypes. This model provides an objective and internally controlled study of distinct islet preparations and documents the temporal histology of IBMIR.


Assuntos
Inflamação/imunologia , Transplante das Ilhotas Pancreáticas/métodos , Ilhotas Pancreáticas/citologia , Animais , Animais Geneticamente Modificados , Glicemia/química , Plaquetas/imunologia , Ativação do Complemento , Modelos Animais de Doenças , Galactosiltransferases/genética , Imuno-Histoquímica , Macaca mulatta , Macrófagos/imunologia , Neutrófilos/imunologia , Fenótipo , Suínos , Fatores de Tempo , Transplante Heterólogo
6.
Br J Surg ; 101(3): 172-88, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24469618

RESUMO

BACKGROUND: Enhanced recovery programmes (ERPs) have been developed over the past 10 years to improve patient outcomes and to accelerate recovery after surgery. The existing literature focuses on specific specialties, mainly colorectal surgery. The aim of this review was to investigate whether the effect of ERPs on patient outcomes varies across surgical specialties or with the design of individual programmes. METHODS: MEDLINE, Embase, CINAHL and the Cochrane Central Register of Controlled Trials were searched from inception to January 2013 for randomized or quasi-randomized trials comparing ERPs with standard care in adult elective surgical patients. RESULTS: Thirty-eight trials were included in the review, with a total of 5099 participants. Study design and quality was poor. Meta-analyses showed that ERPs reduced the primary length of stay (standardized mean difference -1·14 (95 per cent confidence interval -1·45 to -0·85)) and reduced the risk of all complications within 30 days (risk ratio (RR) 0·71, 95 per cent c.i. 0·60 to 0·86). There was no evidence of a reduction in mortality (RR 0·69, 95 per cent c.i. 0·34 to 1·39), major complications (RR 0·95, 0·69 to 1·31) or readmission rates (RR 0·96, 0·59 to 1·58). The impact of ERPs was similar across specialties and there was no consistent evidence that elements included within ERPs affected patient outcomes. CONCLUSION: ERPs are effective in reducing length of hospital stay and overall complication rates across surgical specialties. It was not possible to identify individual components that improved outcome. Qualitative synthesis may be more appropriate to investigate the determinants of success.


Assuntos
Medicina/estatística & dados numéricos , Cuidados Pós-Operatórios/métodos , Complicações Pós-Operatórias/reabilitação , Recuperação de Função Fisiológica , Ensaios Clínicos como Assunto , Humanos , Tempo de Internação , Readmissão do Paciente/estatística & dados numéricos , Cuidados Pós-Operatórios/mortalidade , Complicações Pós-Operatórias/mortalidade , Projetos de Pesquisa , Fatores de Risco
7.
Am J Transplant ; 13(2): 312-9, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23279640

RESUMO

Calcineurin inhibitors (CNI) and steroids are known to promote insulin resistance, and their avoidance after islet transplantation is preferred from a metabolic standpoint. Belatacept, a B7-specific mediator of costimulation blockade (CoB), is clinically indicated as a CNI alternative in renal transplantation, and we have endeavored to develop a clinically translatable, belatacept-based regimen that could obviate the need for both CNIs and steroids. Based on the known synergy between CoB and mTOR inhibition, we studied rhesus monkeys undergoing MHC-mismatched islet allotransplants treated with belatacept and the mTOR inhibitor, sirolimus. To extend prior work on CoB-resistant rejection, some animals also received CD2 blockade with alefacept (LFA3-Ig). Nine rhesus macaques were rendered diabetic with streptozotocin and underwent islet allotransplantation. All received belatacept and sirolimus; six also received alefacept. Belatacept and sirolimus significantly prolonged rejection-free graft survival (median 225 days compared to 8 days in controls receiving basiliximab and sirolimus; p = 0.022). The addition of alefacept provided no additional survival benefit, but was associated with Cytomegalovirus reactivation in four of six animals. No recipients produced donor-specific alloantibodies. The combination of belatacept and sirolimus successfully prevents islet allograft survival in rhesus monkeys, but induction with alefacept provides no survival benefit and increases the risk of viral reactivation.


Assuntos
Imunoconjugados/administração & dosagem , Transplante das Ilhotas Pancreáticas/métodos , Proteínas Recombinantes de Fusão/administração & dosagem , Sirolimo/administração & dosagem , Transplante Homólogo/métodos , Abatacepte , Alefacept , Animais , Anticorpos Monoclonais/administração & dosagem , Basiliximab , Peptídeo C/metabolismo , Diabetes Mellitus Experimental , Sobrevivência de Enxerto , Antígenos de Histocompatibilidade/imunologia , Imunossupressores/administração & dosagem , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/imunologia , Macaca mulatta , Esteroides/administração & dosagem
8.
Lymphology ; 45(2): 47-52, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23057148

RESUMO

Plastic bronchitis is a rare condition characterized by the formation and expectoration of long, branching bronchial casts that develop in the tracheobronchial tree and cause airway obstruction. Plastic bronchitis has become increasingly recognized as a feared complication of the Fontan operation with a mortality of up to 50%. We report an 11 year old boy who developed severe plastic bronchitis following Fontan repair and the successful long-term control of cast formation utilizing a low-fat diet and subsequent thoracic duct ligation.


Assuntos
Bronquite/dietoterapia , Dieta com Restrição de Gorduras , Técnica de Fontan/efeitos adversos , Ducto Torácico/cirurgia , Bronquite/etiologia , Broncoscopia , Criança , Terapia Combinada , Humanos , Ligadura , Masculino , Complicações Pós-Operatórias , Prognóstico
11.
Am Surg ; 61(3): 197-201, 1995 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-7887528

RESUMO

This study was done to investigate whether laparoscopic intracorporeal (LI) or laparoscopic assisted (LA) colon resection results in improved anastomotic healing compared with open colon resection (OR). Thirty-six domestic swine were randomly assigned to undergo either LI, LA, or OR of the rectosigmoid. For OR cases, the sigmoid was resected through a midline incision, and a transanal end-to-end stapled anastomosis was constructed with an ILS device. For LA and LI cases, the sigmoid was laparoscopically mobilized and divided distally, using 5 trocar sites. For LA cases, the proximal sigmoid was brought out through an enlarged trocar site and resected; the ILS anvil was secured to the proximal end, and the colon was replaced in the abdominal cavity where the anastomosis was completed by transanal insertion and firing of ILS device. For LI cases, the sigmoid was resected laparoscopically and retrieved through a 33 mm trocar. The ILS anvil was introduced via the same trocar, and the device was laparoscopically secured with two Endoloop (Ethicon Endo-Surgery, Cincinnati, OH) pursestring sutures. The anastomosis was completed the same way as for LA cases. Animals were killed at 7 days, at which time the anastomoses were evaluated by barium enema, bursting pressure, and histologic appearance. There were no radiographic anastomotic leaks. The mean bursting pressure was 205 +/- 65 mmHg for the 13 OR animals, 240 +/- 53 mmHg for 11 LA animals, and 242 +/- 43 mmHg for the 12 LI animals (N.S.). Histologic evaluation for inflammation indicated no significant differences.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Colo/cirurgia , Laparoscopia/métodos , Anastomose Cirúrgica , Animais , Colo/fisiopatologia , Masculino , Métodos , Complicações Pós-Operatórias , Distribuição Aleatória , Suínos , Resistência à Tração , Fatores de Tempo
12.
Exp Lung Res ; 10(1): 1-22, 1986.
Artigo em Inglês | MEDLINE | ID: mdl-3948809

RESUMO

The effects of the synthetic corticosteroid methylprednisolone (MP; 30 mg/kg, s.c. given twice daily for 3 days), on the pneumotoxic effects of a single dose of butylated hydroxytoluene (BHT; 400 mg/kg, i.p.) over a 10 day experimental period was investigated in male C57BL/6N mice. BHT alone caused time-dependent alveolar hypercellularity, inflammatory infiltration, alveolar septal thickening and hypercellularity of the bronchiolar epithelium, reaching a maximum by day 5 with some degree of recovery by day 10. The pulmonary monooxygenase activities reflected the degree of alveolar damage and Clara cell abnormality with time; reductions in monooxygenase activities occurred and minimum levels (7-15% of control) were reached by day 5 and again a trend towards recovery by day 10. MP administered 0, 24 and 48 hr after BHT treatment partially protected mice from these effects of BHT in a distinctly time-dependent fashion; the degree of protection decreased as the time between BHT challenge and MP treatment increased. Although MP alone did not morphologically affect Clara and alveolar cells, it increased, decreased or had no effect on the monooxygenase activities. About 25% of the mice that received BHT alone died by day 5 and 50% by day 10. MP completely blocked the lethal effects of BHT by day 5 and reduced the deaths to between 15% and 25% by day 10. Interestingly, MP did not protect against the BHT-induced pulmonary fibrosis, measured as total lung hydroxyproline content, irrespective of the time between BHT challenge and MP treatment. MP alone did not cause any deaths nor increase lung hydroxyproline content.


Assuntos
Hidroxitolueno Butilado/antagonistas & inibidores , Pulmão/efeitos dos fármacos , Metilprednisolona/farmacologia , Fibrose Pulmonar/induzido quimicamente , Animais , Hidroxitolueno Butilado/toxicidade , Hidroxiprolina/metabolismo , Pulmão/metabolismo , Pulmão/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microssomos/efeitos dos fármacos , Microssomos/enzimologia , Oxigenases de Função Mista/antagonistas & inibidores , Fibrose Pulmonar/metabolismo , Fibrose Pulmonar/prevenção & controle , Fatores de Tempo
13.
Artigo em Inglês | MEDLINE | ID: mdl-4067835

RESUMO

The effects of toxic doses of various drugs and of food or water deprivation upon heart weights of mice were evaluated over a four day period to test the validity of the hypothesis that changes in cardiac weights are indicators of cardiotoxicity. Drugs included in the study were actinomycin-D, methotrexate, 5-fluorouracil, adriamycin, daunomycin, N-dimethyladriamycin, N-trifluoroacetyladriamycin-14-valerate, isoproterenol, atropine, and acetylsalicylic acid. Additional groups of mice served as vehicle controls, or were deprived of food or water for the duration of the experiment to control for the anorexia and dehydration accompanying treatment with antineoplastic drugs. Body weights were taken at the start of the experiment (day 0), day 2, and day 4 (just prior to sacrifice). Heart ventricle wet weights were determined immediately, and dry weights after thorough desiccation of the samples. Statistical evaluation of the weights revealed that there were no ventricular weight changes unique to any particular drug, and that decreases in heart weights correlated well with decreases in body weights, thereby reflecting the general toxicities of the drugs, including inanition, and not any specific cardiotoxicities.


Assuntos
Antibióticos Antineoplásicos/toxicidade , Cardiopatias/induzido quimicamente , Coração/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Doxorrubicina/toxicidade , Cardiopatias/diagnóstico , Ventrículos do Coração/efeitos dos fármacos , Masculino , Camundongos , Tamanho do Órgão/efeitos dos fármacos , Fatores de Tempo
14.
Toxicol Appl Pharmacol ; 74(2): 201-13, 1984 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-6740671

RESUMO

A single ip dose of 1,1-dichloroethylene (DCE) to mice (125 mg/kg) caused a reduction within 24 hr in cytochrome P-450 and related monooxygenases in lung microsomes, with no corresponding changes in liver and kidney microsomes. Light microscopy revealed that at 24 hr, DCE caused a highly selective and complete loss of the bronchiolar nonciliated (Clara) cells at all levels of the tracheobronchial tree. Electron microscopy showed that at this time, the bronchiolar luminal surface was covered by flattened, elongated ciliated cells. Within 24 hr total microsomal cytochrome P-450 and NADPH cytochrome c reductase were maximally reduced to about 50% of control and cytochrome P-450-dependent enzyme activities decreased to about 60% of control. By contrast, coumarin 7-hydroxylase was reduced to approximately 10% of control within 4 days. Since pulmonary coumarin 7-hydroxylase has been shown to reside almost exclusively in the Clara cells, this finding is in agreement with the observed extensive necrosis of the Clara cells. The return of lung microsomal P-450-linked enzyme activities took between 3 and 6 weeks and was paralleled by a corresponding slow reappearance of the bronchiolar Clara cells.


Assuntos
Dicloroetilenos/toxicidade , Hidrocarbonetos Clorados/toxicidade , Pulmão/efeitos dos fármacos , Oxigenases/antagonistas & inibidores , Animais , Brônquios/efeitos dos fármacos , Brônquios/patologia , Sistema Enzimático do Citocromo P-450 , Epitélio/efeitos dos fármacos , Epitélio/patologia , Rim/efeitos dos fármacos , Rim/enzimologia , Fígado/efeitos dos fármacos , Fígado/enzimologia , Pulmão/enzimologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microssomos/efeitos dos fármacos , Microssomos/enzimologia , Oxigenases de Função Mista/antagonistas & inibidores
15.
J Natl Cancer Inst ; 70(2): 337-42, 1983 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-6337293

RESUMO

The immunocytochemical localization of catechol methyltransferase was determined in normal and cancerous breast tissues of inbred female Swiss-Webster mice and in normal, lactating, and cancerous breast tissues of inbred Sprague-Dawley rats. The enzyme was found to be cytoplasmically localized in ductal epithelial cells of secretory tubules in both inactive and stimulated mammary glands, in endothelial cells lining blood vessels, in fibroblasts in the connective tissue matrix, and, especially, in tumor cells. Adipose cells were nonreactive. The intensity of the immunocytochemical reaction in tumor cells was stronger than that in lactating tissues, which, in turn, was more reactive than that in normal, unstimulated breast tissues.


Assuntos
Catecol O-Metiltransferase/análise , Adenocarcinoma/enzimologia , Tecido Adiposo/enzimologia , Animais , Citoplasma/enzimologia , Epitélio/enzimologia , Feminino , Fibroblastos/enzimologia , Histocitoquímica , Técnicas Imunológicas , Lactação , Neoplasias Mamárias Experimentais/enzimologia , Camundongos , Camundongos Endogâmicos , Gravidez , Ratos , Ratos Endogâmicos
16.
Biochem Biophys Res Commun ; 110(2): 675-81, 1983 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-6838545

RESUMO

The acute toxic effects of 1,1-dichloroethylene (DCE; 125 mg/kg, i.p.) on mouse lung, liver and kidney were investigated 24 hr after its administration. DCE caused a reduction of cytochrome P-450 levels and related monooxygenases in lung microsomes with no corresponding changes in liver and kidney. Examination of the lung tissue by light microscopy revealed necrosis restricted to the Clara cells. In contrast, liver and kidney were relatively unaffected by DCE treatment, as indicated by lack of changes in microsomal monooxygenase activities and morphology.


Assuntos
Dicloroetilenos/toxicidade , Hidrocarbonetos Clorados/toxicidade , Pulmão/patologia , Oxigenases/antagonistas & inibidores , Animais , Sistema Enzimático do Citocromo P-450 , Rim/efeitos dos fármacos , Rim/patologia , Fígado/efeitos dos fármacos , Fígado/patologia , Pulmão/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microssomos Hepáticos/enzimologia
17.
Oncology ; 40(5): 340-3, 1983.
Artigo em Inglês | MEDLINE | ID: mdl-6621996

RESUMO

A study of the cardiotoxicity induced by adriamycin (ADR) was done on the heart tissue of Sprague-Dawley rats receiving a single intravenous dose (15 mg/kg). Condensed bright orange-red fluoresced chromatin was observed in the nuclei of the myocardial cells of the left ventricle 2 h after drug injection. Just then, the intensity of the fluorescence emission started to decrease until it reached its minimum after 21 days, and disappeared completely 28 days after drug injection.


Assuntos
Doxorrubicina/metabolismo , Miocárdio/metabolismo , Animais , Sítios de Ligação , Masculino , Microscopia de Fluorescência , Ratos , Ratos Endogâmicos , Fatores de Tempo
20.
Biochemistry ; 21(3): 503-9, 1982 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-6121582

RESUMO

We have examined the effects of a number of organic anions, which stabilize tubulin, on tubulin polymerization, associated GTP hydrolysis, and polymer morphology. While microtubule-associated proteins, as well as glycerol, induced formation of typical microtubules in a reaction coupled to GTP hydrolysis at an initial 1:1 stoichiometry, the organic anions had varying effects. Only 2-(N-morpholino)ethanesulfonate induced formation of structures with the morphology of microtubules. With glutamate, fructose 1,6-bisphosphate, piperazine-N-N'-bis(2-ethanesulfonate), glutarate, and glucose 1-phosphate, the predominant structures formed were sheets of parallel protofilaments rather than microtubules. Creatine phosphate induced the formation of clusters of rings. GTP hydrolysis was closely coupled to polymerization only with glutamate. With creatine phosphate, there was minimal GTP hydrolysis. With all other organic anions, GTP hydrolysis substantially exceeded polymerization at all time points, with the onset of hydrolysis significantly preceding the onset of turbidity development. Nevertheless, the rate of GTP hydrolysis was a sigmoidal function of tubulin concentration under all conditions examined, suggesting that tubulin-tubulin interactions are required for hydrolysis. All anion-induced reactions were temperature dependent and cold reversible, but only the creatine phosphate induced reaction was not inhibited by GDP, CA2+, or colchicine and did not require GTP.


Assuntos
Guanosina Trifosfato/metabolismo , Tubulina (Proteína)/metabolismo , Animais , Ânions , Encéfalo/metabolismo , Bovinos , GTP Fosfo-Hidrolases/metabolismo , Cinética , Substâncias Macromoleculares , Microscopia Eletrônica , Proteínas Associadas aos Microtúbulos , Proteínas do Tecido Nervoso/metabolismo , Proteínas/metabolismo
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