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1.
Osteoarthritis Cartilage ; 27(5): 823-832, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30711608

RESUMO

OBJECTIVE: During osteoarthritis (OA), chondrocytes seem to change their spatial arrangement from single to double strings, small and big clusters. Since the pericellular matrix (PCM) appears to degrade alongside this reorganisation, it has been suggested that spatial patterns act as an image-based biomarker for OA. The aim of this study was to establish the functional relevance of spatial organisation in articular cartilage. METHOD: Cartilage samples were selected according to their predominant spatial cellular pattern. Young's modulus of their PCM was measured by atomic force microscopy (AFM) (∼500 measurements/pattern). The distribution of two major PCM components (collagen type VI and perlecan) was analysed by immunohistochemistry (8 patients) and protein content quantified by enzyme-linked immunosorbent assay (ELISA) (58 patients). RESULTS: PCM stiffness significantly decreased with the development from single to double strings (p = 0.030), from double strings to small clusters (p = 0.015), and from small clusters to big clusters (p < 0.001). At the same time, the initially compact collagen type VI and perlecan staining progressively weakened and was less focalised. The earliest point with a significant reduction in protein content as shown by ELISA was the transition from single strings to small clusters for collagen type VI (p = 0.016) and from double strings to small clusters for perlecan (p = 0.008), with the lowest amounts for both proteins seen in big clusters. CONCLUSIONS: This study demonstrates the functional relevance of spatial chondrocyte organisation as an image-based biomarker. At the transition from single to double strings PCM stiffness decreases, followed by protein degradation from double strings to small clusters.


Assuntos
Cartilagem Articular/patologia , Condrócitos/patologia , Osteoartrite do Joelho/patologia , Artroplastia do Joelho , Fenômenos Biomecânicos , Cartilagem Articular/metabolismo , Cartilagem Articular/fisiopatologia , Condrócitos/fisiologia , Colágeno Tipo VI/metabolismo , Elasticidade , Ensaio de Imunoadsorção Enzimática/métodos , Espaço Extracelular/metabolismo , Espaço Extracelular/fisiologia , Proteoglicanas de Heparan Sulfato/metabolismo , Humanos , Microscopia de Força Atômica/métodos , Osteoartrite do Joelho/metabolismo , Osteoartrite do Joelho/fisiopatologia , Manejo de Espécimes/métodos
2.
Br J Cancer ; 112(3): 455-60, 2015 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-25535732

RESUMO

BACKGROUND: We sought to examine whether mitotic count (MC) and the amount of viable tumour (VT) following neoadjuvant systemic chemotherapy (SC) for primary, localised, high-grade soft tissue sarcoma (STS) correlate with prognosis. METHODS: Retrospective analysis of 57 patients who underwent SC involving a combination of an anthracycline and an alkylating agent, followed by surgical resection between 2001 and 2011. RESULTS: The amount of VT after chemotherapy was significantly associated with disease-specific survival (DSS) and event-free survival (EFS). Patients with <10% VT had a DSS of 94% at 5 years, compared with 61% for patients with ⩾10% VT (P=0.033); EFS was 75%, compared with 48% (P=0.030). Patients with an MC of ⩾20/10 high power fields (HPF) after chemotherapy had a significantly lower DSS (33% vs 84% at 5 years, P<0.001) and EFS (40% vs 63% at 5 years, P=0.019) than patients with an MC of <20/10 HPF. CONCLUSIONS: The MC and the amount of VT after neoadjuvant therapy for primary, localised, high-grade STS appear to correlate with prognosis. If these results are validated prospectively, then they could provide a rational for the design of neoadjuvant treatment modification/escalation studies, analogue to the EURAMOS-1 trial for bone sarcomas.


Assuntos
Antineoplásicos/uso terapêutico , Índice Mitótico , Sarcoma/mortalidade , Sarcoma/patologia , Neoplasias de Tecidos Moles/mortalidade , Neoplasias de Tecidos Moles/patologia , Adolescente , Adulto , Idoso , Antraciclinas/administração & dosagem , Antineoplásicos Alquilantes/administração & dosagem , Sobrevivência Celular/efeitos dos fármacos , Intervalo Livre de Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Terapia Neoadjuvante , Gradação de Tumores , Neoplasia Residual , Valor Preditivo dos Testes , Prognóstico , Estudos Retrospectivos , Sarcoma/terapia , Neoplasias de Tecidos Moles/terapia , Adulto Jovem
3.
Unfallchirurgie (Heidelb) ; 126(1): 72-76, 2023 Jan.
Artigo em Alemão | MEDLINE | ID: mdl-35376966

RESUMO

Atypical femoral fractures are a very rare complication after treatment with bisphosphonates. This case report describes the diagnostic criteria and some particularities of the surgical treatment. Atypical femoral fractures are typically stabilized with intramedullary nails but some pitfalls in surgical treatment, e.g. the choice of implant, have to be considered. Basically, these fractures can be treated using conventional intramedullary nails, which, however, must be used by being adapted depending on the morphology of the femur. The fact that atypical femoral fractures can occur under bisphosphonate treatment should in no way influence the indications for starting anti-osteoporotic treatment.


Assuntos
Conservadores da Densidade Óssea , Fraturas do Fêmur , Fixação Intramedular de Fraturas , Humanos , Conservadores da Densidade Óssea/efeitos adversos , Fraturas do Fêmur/diagnóstico por imagem , Difosfonatos/efeitos adversos , Fixação Intramedular de Fraturas/efeitos adversos , Fêmur
4.
Int J Colorectal Dis ; 27(7): 879-84, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22173715

RESUMO

PURPOSE: Radiotherapy is one of the important treatment modalities for tumors of pelvic organs. The fixed location of the rectum and its anatomic relationship with other pelvic organs makes it prone to radiation injury resulting in chronic radiation proctopathy in 5% to 20% of patients. Endothelial dysfunction has been associated with a number of pathophysiological processes. Endothelial cells synthesize and release various factors that regulate angiogenesis, inflammatory responses, hemostasis, as well as vascular tone and permeability. METHODS: Rectum tissue samples from 20 patients with established chronic radiation proctopathy were analysed for the expression of genes related to oxidative stress, tissue hypoxia, angiogenesis, and inflammation [endoglin (ENG), activin receptor-like kinase 1 (ALK1), platelet endothelial cell adhesion molecule 1 (PECAM), vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF2), hypoxia-inducible factor 1 (HIF-1), and interleukin-1 beta (IL-1ß)]. RESULTS: Overexpression of HIF-1, VEGF, FGF2, and IL-1ß was detected in affected tissue. For the first time, a significant suppression of activin receptor-like kinase 1 and ENG could be revealed. CONCLUSION: The data provided here allow further insight into the pathogenesis of radiation-induced rectum injury. Radiation-induced damage is not confined to a single event but involves complex signaling between different pathways, enhancing and maintaining the processes that lead to mucosal damage. The results indicate that postradiation tissue hypoxia is critical for fibrosis, which involves changes in the expression of profibrotic and angiogenic factors in rectal tissue.


Assuntos
Perfilação da Expressão Gênica , Radioterapia/efeitos adversos , Doenças Retais/etiologia , Doenças Retais/genética , Receptores de Activinas Tipo II/genética , Receptores de Activinas Tipo II/metabolismo , Idoso , Antígenos CD/genética , Antígenos CD/metabolismo , Endoglina , Feminino , Fator 2 de Crescimento de Fibroblastos/genética , Fator 2 de Crescimento de Fibroblastos/metabolismo , Regulação da Expressão Gênica , Humanos , Fator 1 Induzível por Hipóxia/genética , Fator 1 Induzível por Hipóxia/metabolismo , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Masculino , Pessoa de Meia-Idade , Molécula-1 de Adesão Celular Endotelial a Plaquetas/genética , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo
5.
Bone Joint J ; 102-B(5): 638-645, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32349590

RESUMO

AIMS: Accurate estimations of the risk of fracture due to metastatic bone disease in the femur is essential in order to avoid both under-treatment and over-treatment of patients with an impending pathological fracture. The purpose of the current retrospective in vivo study was to use CT-based finite element analyses (CTFEA) to identify a clear quantitative differentiating factor between patients who are at imminent risk of fracturing their femur and those who are not, and to identify the exact location of maximal weakness where the fracture is most likely to occur. METHODS: Data were collected on 82 patients with femoral metastatic bone disease, 41 of whom did not undergo prophylactic fixation. A total of 15 had a pathological fracture within six months following the CT scan, and 26 were fracture-free during the five months following the scan. The Mirels score and strain fold ratio (SFR) based on CTFEA was computed for all patients. A SFR value of 1.48 was used as the threshold for a pathological fracture. The sensitivity, specificity, positive, and negative predicted values for Mirels score and SFR predictions were computed for nine patients who fractured and 24 who did not, as well as a comparison of areas under the receiver operating characteristic curves (AUC of the ROC curves). RESULTS: The sensitivity of SFR was 100% compared with 88% for the Mirels score, and the specificity of SFR was 67% compared with 38% for the Mirels score. The AUC was 0.905 for SFR compared with 0.578 for the Mirels score (p = 0.008). CONCLUSION: All the patients who sustained a pathological fracture of the femur had an SFR of > 1.48. CTFEA was far better at predicting the risk of fracture and its location accurately compared with the Mirels score. CTFEA is quick and automated and can be incorporated into the protocol of CT scanners. Cite this article: Bone Joint J 2020;102-B(5):638-645.


Assuntos
Fraturas do Fêmur/diagnóstico por imagem , Neoplasias Femorais/diagnóstico por imagem , Neoplasias Femorais/secundário , Fraturas Espontâneas/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Idoso , Feminino , Análise de Elementos Finitos , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Retrospectivos , Sensibilidade e Especificidade
6.
J Bone Joint Surg Am ; 102(19): 1703-1713, 2020 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-33027124

RESUMO

BACKGROUND: Osteofibrous dysplasia-like adamantinoma (OFD-AD) and classic adamantinoma (AD) are rare, neoplastic diseases with only limited data supporting current treatment protocols. We believe that our retrospective multicenter cohort study is the largest analysis of patients with adamantinoma to date. The primary purpose of this study was to describe the disease characteristics and evaluate the oncological outcomes. The secondary purpose was to identify risk factors for local recurrence after surgical treatment and propose treatment guidelines. METHODS: Three hundred and eighteen confirmed cases of OFD-AD and AD for which primary treatment was carried out between 1985 and 2015 were submitted by 22 tertiary bone tumor centers. Proposed clinical risk factors for local recurrence such as size, type, and margins were analyzed using univariable and multivariate Cox regression analysis. RESULTS: Of the 318 cases, 128 were OFD-AD and 190 were AD. The mean age at diagnosis was 17 years (median, 14.5 years) for OFD-AD and 32 years (median, 28 years) for AD; 53% of the patients were female. The mean tumor size in the OFD-AD and AD groups combined was 7.8 cm, measured histologically. Sixteen percent of the patients sustained a pathological fracture prior to treatment. Local recurrence was recorded in 22% of the OFD-AD cases and 24% of the AD cases. None of the recurrences in the OFD-AD group progressed to AD. Metastatic disease was found in 18% of the AD cases and fatal disease, in 11% of the AD cases. No metastatic or fatal disease was reported in the OFD-AD group. Multivariate Cox regression analysis demonstrated that uncontaminated resection margins (hazard ratio [HR] = 0.164, 95% confidence interval [CI] = 0.092 to 0.290, p < 0.001), pathological fracture (HR = 1.968, 95% CI = 1.076 to 3.600, p = 0.028), and sex (female versus male: HR = 0.535, 95% CI = 0.300 to 0.952, p = 0.033) impacted the risk of local recurrence. CONCLUSIONS: OFD-AD and AD are parts of a disease spectrum but should be regarded as different entities. Our results support reclassification of OFD-AD into the intermediate locally aggressive category, based on the local recurrence rate of 22% and absence of metastases. In our study, metastatic disease was restricted to the AD group (an 18% rate). We advocate wide resection with uncontaminated margins including bone and involved periosteum for both OFD-AD and AD. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.


Assuntos
Adamantinoma/cirurgia , Doenças do Desenvolvimento Ósseo/cirurgia , Neoplasias Ósseas/cirurgia , Adamantinoma/patologia , Adolescente , Adulto , Doenças do Desenvolvimento Ósseo/patologia , Neoplasias Ósseas/patologia , Feminino , Humanos , Masculino , Recidiva Local de Neoplasia , Prognóstico , Fatores de Risco , Resultado do Tratamento
7.
Transplant Proc ; 40(4): 981-2, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18555095

RESUMO

UNLABELLED: The short cold ischemic tolerance of the gut is a major problem in small bowel transplantation. We have shown that intestinal lipid administration is beneficial during systemic inflammation like sepsis. METHODS: Rats were intestinally infused with either water or 1% olive oil for 12 hours. The small bowel was removed and stored in HTK solution on ice. At t = 0, t = 60, t = 120, t = 180, t = 240, t = 300, t = 360, t = 420, and t = 480 minutes, a tissue sample of the gut was fixed, stained, and analyzed by three independent observers. Damage score was calculated (0 = no damage, 1 = minor damage, 2 = major damage, 3 = loss of structure) for integrity of the mucosa, integrity of the basal membrane of the mucosa, and integrity of villy. The damage score was allocated when all three observers agreed on the same or a higher damage score. RESULTS: In all control animals minor damage for the integrity of the basal membrane occurred within 60 minutes, but in only 50% of the lipid-treated rats. In all control rats, major damage for both integrity of mucosa and villi occurred within 300 minutes or less, but only in 50% of the lipid-treated rats. In all control rats, the structure of the villi was completely lost within 480 minutes or less, whereas only 50% of the lipid treated animals reached maximal damage scores for either mucosa or villi. CONCLUSION: Intestinal lipid administration before cold storage clearly decreases histologic damage of the small bowel and might increase the tolerance for cold ischemia. Lipids or their metabolites stored in enterocytes may act as an antiinflammatory. Intestinal lipid administration in organ donors might be useful to increase cold ischemic tolerance of the small bowel.


Assuntos
Absorção Intestinal , Intestino Delgado/fisiopatologia , Isquemia/fisiopatologia , Lipídeos/fisiologia , Óleos de Plantas/farmacologia , Animais , Mucosa Intestinal/efeitos dos fármacos , Intestino Delgado/irrigação sanguínea , Intestino Delgado/efeitos dos fármacos , Masculino , Azeite de Oliva , Soluções para Preservação de Órgãos , Ratos , Ratos Sprague-Dawley
8.
Endoscopy ; 39(12): 1100-2, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18072063

RESUMO

Gastric perforation is a rare complication after acute necrotizing pancreatitis. We describe endoscopic closure of a gastric perforation that appeared 4 days after surgical necrosectomy including splenectomy due to necrotizing pancreatitis, using the over-the-scope clip (OTSC) system (Ovesco Endoscopy GmbH, Tübingen, Germany). The clips, which are made of nitinol, are loaded onto an application cap which is mounted on the distal tip of the endoscope. The lesion was closed with two clips and the patient recovered well without reinterventions. The lesions showed normal healing on follow-up.


Assuntos
Gastroscopia/métodos , Pancreatite Necrosante Aguda/complicações , Ruptura Gástrica/cirurgia , Adulto , Endoscopia/métodos , Seguimentos , Gastroscópios , Humanos , Masculino , Pancreatectomia/efeitos adversos , Pancreatectomia/métodos , Pancreatite Necrosante Aguda/diagnóstico , Pancreatite Necrosante Aguda/cirurgia , Complicações Pós-Operatórias/cirurgia , Medição de Risco , Esplenectomia/efeitos adversos , Esplenectomia/métodos , Ruptura Gástrica/etiologia , Instrumentos Cirúrgicos , Resultado do Tratamento
9.
Cardiovasc Res ; 10(5): 514-23, 1976 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-134829

RESUMO

The well-known effects of dipyridamole on the increase of the coronary vessel system and on cardiac metabolism suggest that dipyridamole may have a favourable influence on the chronic pressure loaded heart. In the model of the aorta-stenosed growing rabbit the cardiomegaly was diminished after a 3-month treatment using high doses of dipyridamole. Histometrically a marked decrease of the enlargement of the cross-sectional area of muscle fibres was found. It is assumed that dipyridamole retards myocardial hypertrophy and stimulates hyperplasia. Simultaneously the impairment of distinct parameters of cardiac contractility in the aorta-stenosed heart was prevented in growing rabbits by long-term dipyridamole treatment.


Assuntos
Cardiomegalia/tratamento farmacológico , Dipiridamol/uso terapêutico , Contração Miocárdica/efeitos dos fármacos , Animais , Estenose da Valva Aórtica/fisiopatologia , Pressão Sanguínea/efeitos dos fármacos , Dipiridamol/farmacologia , Modelos Animais de Doenças , Feminino , Masculino , Tamanho do Órgão/efeitos dos fármacos , Coelhos
10.
Comput Aided Surg ; 9(3): 71-9, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15792939

RESUMO

OBJECTIVE: Using fluoroscopic images alone, it is difficult to guarantee that screws are positioned within the femoral head and neck. This study evaluates whether the introduction of deformable 3D models limiting the planning and navigation space is a helpful approach to minimizing the incidence of misplaced screws, thereby enhancing patient safety. BACKGROUND: Even though a screw may appear to lie within the femoral head and neck on fluoroscopic images, this may not, in fact, be the case. This is a particular problem for interventions such as fixation of a slipped femoral head or osteosynthesis of the femoral neck, where screws must be set close to the cortical bone without penetrating the joint or injuring the cortex of the femoral neck. METHODS: A system was developed which permits computer-based planning and navigation of screws for femoral neck fracture fixation based on fluoroscopic images. Different approaches were employed which either a) make use of a deformable model adapted to the femoral head/neck, constraining the screw positions within this model; or b) allow the user to position the screws with or without geometrical constraints on the X-rays while maintaining parallelism of the screws. All designs were evaluated and compared by 7 test users using integral projection X-rays calculated from the CT dataset. Results were checked using a 3D model of the bone, also calculated from the CT dataset. RESULTS: Positioning screws using the deformable model resulted in a significantly smaller distribution of screw tip locations and no penetrations into the hip joint, in contrast to the other approaches where up to 11% of screws were misplaced. CONCLUSIONS: Constraining the planning and navigation space by means of a deformable model allows better control of screw positioning and thus increases the chances of a successful intervention. In particular, CAS systems allowing for virtual fluoroscopy should consider supporting this planning approach.


Assuntos
Fraturas do Colo Femoral/cirurgia , Fixação de Fratura , Imageamento Tridimensional , Cirurgia Assistida por Computador , Parafusos Ósseos , Simulação por Computador , Fraturas do Colo Femoral/diagnóstico por imagem , Fluoroscopia , Humanos , Modelos Biológicos , Reprodutibilidade dos Testes
11.
Biomed Tech (Berl) ; 47 Suppl 1 Pt 1: 93-6, 2002.
Artigo em Alemão | MEDLINE | ID: mdl-12451782

RESUMO

To investigate how surgeons can be supported in planning of screws for femoral neck fracture fixation reducing incidents of misplaced screws, a system was developed which makes use of a deformable model to be adapted to the femoral head/neck. The accuracy and usability of the system was checked against planning support systems mimicking the conventional positioning of screws within bi-planar x-rays. All designs were evaluated and compared by N = 7 test user. Checking the rate of misplaced screws a) at the femoral neck yielded rates of 8% or up to 42%, b) at the femoral head yielded rates of 0% or up to 11% for model-based or conventional planning, respectively. It is thus suggested to constrain the planning and navigation space by means of deformable models of the bone.


Assuntos
Simulação por Computador , Fraturas do Colo Femoral/cirurgia , Fixação Interna de Fraturas , Cirurgia Assistida por Computador , Parafusos Ósseos , Humanos , Imageamento Tridimensional
14.
Thorax ; 61(11): 986-91, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16893947

RESUMO

BACKGROUND: The mucosal immune system undergoes extensive changes in early childhood in response to environmental stimuli. Dendritic cells (DC) play a major role in the development of the immune system. However, few data exist on the influence of continuous environmental stimulation on the distribution and phenotype of human airway DC. METHODS: Human tissue samples are mostly paraffin embedded which limits the use of several antibodies, and respiratory tissue for cryopreservation is difficult to obtain. Human frozen post mortem tracheal tissue was therefore used for this study. Only samples with epithelial adherence to the basement membrane were included (n = 34). Immunohistochemical staining and sequential overlay immunofluorescence were performed with DC-SIGN and a panel of leucocyte markers co-expressed by DC. RESULTS: DC detected in the human tracheal mucosa using DC-SIGN correlated with the expression of HLA-DR, co-stimulatory and adhesion molecules. Higher cell densities were found at the ventral tracheal site of patients older than 1 year than in infants in the first year of life. CONCLUSION: The increasing population of mucosal DC with age could reflect immunological maturation.


Assuntos
Células Dendríticas/citologia , Mucosa Respiratória/citologia , Traqueia/citologia , Adulto , Fatores Etários , Idoso , Feminino , Imunofluorescência , Humanos , Imunidade Celular , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade
15.
J Virol ; 49(3): 892-901, 1984 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-6366245

RESUMO

Formation of the prohead core of bacteriophage T4 was not dependent on shell assembly. In mutant infections, where the production or assembly of active shell protein was not possible, naked core structures were formed. The particles were generally attached to the bacterial inner membrane and possessed defined prolate dimensions. The intracellular yield varied between 15 and 71% of a corresponding prohead yield and was dependent on the temperature of incubation. The products of genes 21 and 22 were found to be essential for in vivo core formation, whereas those of genes 20, 23, 24, 31, and 40, as well as the internal proteins I to III, were dispensable.


Assuntos
Fagos T/crescimento & desenvolvimento , Escherichia coli , Microscopia Eletrônica , Morfogênese , Fagos T/ultraestrutura , Proteínas do Core Viral , Proteínas Virais/metabolismo
16.
Arch Geschwulstforsch ; 45(2): 97-110, 1975.
Artigo em Alemão | MEDLINE | ID: mdl-1203024

RESUMO

Newborn rats were given subcutaneuously 85 mg ethylnitrosourea/kg body weight. The trigeminal nerves of the grown up and of infantile animals were histologically examined and their beta-glucuronidase activity biochemically determined. These activities were compared with those of untreated control animals of the same age. More than 50% of the enzyme values of the experimental animals were significantly higher than those of the controls. Most of the elevated activities were encountered in the central part of the nerve and consisted mainly of the pooled soluble and bound fraction of the enzyme. There is a positive correlation between the level of the enzymatic activity and the degree of morphological changes. An increased enzymatic activity was found in almost 100% of the tumor bearing nerves. Moreover such increased activities were found in a considerable number of histologically tumor free nerves. Ruling out other causes, for instance inflammation, it may be assumed that the increased activity of beta-glucuronidase in the trigeminal nerve of the rat after application of ethylnitrosourea is an expression of its carcinogenic effect and precedes the histologically visible alterations.


Assuntos
Glucuronidase/sangue , Nervo Trigêmeo/enzimologia , Animais , Sítios de Ligação , Carcinógenos/administração & dosagem , Etilnitrosoureia/administração & dosagem , Feminino , Masculino , Ratos , Nervo Trigêmeo/efeitos dos fármacos , Nervo Trigêmeo/ultraestrutura
17.
J Virol ; 61(1): 113-8, 1987 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-3537341

RESUMO

Bacteriophage T4 assembly was impaired in Escherichia coli hdB3-1 at an incubation temperature below 30 degrees C. Naked prohead cores (head scaffold) bound to the inner surface of the plasma membrane accumulated, and the major shell protein (gp23) precipitated into visible intracellular aggregates in the cytoplasm. Shifting the temperature to 42 degrees C allowed newly synthesized gp23 to assemble around the accumulated cores. We conclude that synchronous assembly of the scaffold and shell is not obligatory and that naked cores can serve as intermediates in the T4 assembly pathway.


Assuntos
Escherichia coli/ultraestrutura , Fagos T/ultraestrutura , Membrana Celular/metabolismo , Membrana Celular/ultraestrutura , Escherichia coli/genética , Escherichia coli/metabolismo , Microscopia Eletrônica , Mutação , Fagos T/genética , Fagos T/metabolismo
18.
J Virol ; 49(3): 902-8, 1984 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-6422052

RESUMO

The naked core of bacteriophage T4 was isolated ex vivo after cross-linking with either glutaraldehyde or dithiobis(succinimidyl propionate). The isolated particles appeared to be morphologically identical to the cores found in thin sections, to those demonstrated in in situ lysis preparations, and to core structures assembled in vitro. Treatment with glutaraldehyde provided core particles which were morphologically well preserved, whereas dithiobis(succinimidyl propionate)-induced cross-linking was reversible and allowed analysis of the protein composition of the isolated particles. The identity of the reversibly cross-linked particles with those obtained after irreversible cross-linking was suggested by their morphology and their similar sedimentation behavior. Immunolabeling confirmed the structural presence of the main core protein in both structures. Gel electrophoresis of reversibly cross-linked cores revealed the essential head proteins gp22, gp67, and gp21, the three internal proteins IPI, IPII, and IPIII, and a 17K protein.


Assuntos
Fagos T/análise , Proteínas Virais/análise , Anticorpos Antivirais , Reagentes de Ligações Cruzadas/farmacologia , Eletroforese em Gel de Poliacrilamida , Escherichia coli , Glutaral/farmacologia , Microscopia Eletrônica , Succinimidas/farmacologia , Fagos T/ultraestrutura , Proteínas do Core Viral , Proteínas Virais/imunologia
19.
Appl Environ Microbiol ; 53(9): 2077-81, 1987 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2823708

RESUMO

Using a previously developed filter adsorption technique, the inactivation of a human rotavirus, a coxsackievirus B5, and a bovine parvovirus was monitored during sludge treatment processes. During conventional anaerobic mesophilic digestion at 35 to 36 degrees C, only minor inactivation of all three viruses occurred. The k' values measured were 0.314 log10 unit/day for rotavirus, 0.475 log10 unit/day for coxsackievirus B5, and 0.944 log10 unit/day for parvovirus. However, anaerobic thermophilic digestion at 54 to 56 degrees C led to rapid inactivation of rotavirus (k' greater than 8.5 log10 units/h) and of coxsackievirus B5 (k' greater than 0.93 log10 unit/min). Similarly, aerobic thermophilic fermentation at 60 to 61 degrees C rapidly inactivated rotavirus (k' = 0.75 log10 unit/min) and coxsackievirus B5 (k' greater than 1.67 log10 units/min). Infectivity of parvovirus, however, was only reduced by 0.213 log10 unit/h during anaerobic thermophilic digestion and by 0.353 log10 unit/h during aerobic thermophilic fermentation. Furthermore, pasteurization at 70 degrees C for 30 min inactivated the parvovirus by 0.72 log10 unit/30 min. In all experiments the contribution of temperature to the total inactivation was determined separately and was found to be predominant at process temperatures above 54 degrees C. In conclusion, the most favorable treatment to render sludge hygienically safe from the virological point of view would be a thermal treatment (60 degrees C) to inactivate thermolabile viruses, followed by an anaerobic mesophilic digestion to eliminate thermostable viruses that are more sensitive to chemical and microbial inactivations.


Assuntos
Enterovirus Humano B/crescimento & desenvolvimento , Parvoviridae/crescimento & desenvolvimento , Rotavirus/crescimento & desenvolvimento , Esgotos , Anaerobiose , Animais , Linhagem Celular , Meios de Cultura , Temperatura Alta , Humanos , Células Vero
20.
Appl Environ Microbiol ; 52(3): 498-503, 1986 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-3532955

RESUMO

A simple and reliable method is described which allows determination of virus inactivation rates during sludge treatment processes in situ. Bacteriophage f2 was adsorbed onto an electropositive membrane filter which was then sandwiched between two polycarbonate membranes with pores smaller than the virus diameter. The resulting sandwich was fixed in an open filter holder, and several such devices were connected before being exposed in sludge-digesting tanks. The device described prevented uncontrolled virus escape, but allowed direct contact of the various inactivating or stabilizing substances present in the environment tested with the virus adsorbed to the carrier membrane. After exposure to an environment, the surviving fraction of virus was eluted from the inner filter and determined by plaque counting. By using polycarbonate membranes without pores for sandwiching, the influence of temperature alone on virus inactivation could be measured. Thermophilic fermentation at 60 degrees C and at 65 kPa pressure led to a bacteriophage f2 titer reduction of 3.5 log10 units per h, whereas during thermophilic digestion at 54.5 degrees C titers decreased 1.2 log10 units per h. During mesophilic digestion an inactivation rate of only 0.04 log10 units per h was observed. Under these latter conditions, temperature had only a minor effect (19%) on virus inactivation, whereas at 54.5 degrees C during thermophilic digestion heat accounted for 32% of the total inactivation, and during thermophilic fermentation at 60 degrees C temperature and pressure were 100% responsible for virus denaturation.


Assuntos
Bacteriófagos/crescimento & desenvolvimento , Esgotos , Escherichia coli , Filtração , Humanos , Concentração de Íons de Hidrogênio , Temperatura , Eliminação de Resíduos Líquidos
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