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1.
Vet Ophthalmol ; 26(3): 231-237, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37092364

RESUMO

A 10-year-old male castrated Labrador Retriever cross was referred for evaluation of acute vision loss. Ophthalmic examination revealed mild left sided exophthalmos, bilateral resting mydriasis, an absent direct and reduced consensual PLR in the left eye and reduced direct and absent consensual PLR in the right eye. Examination of the cornea and anterior segment with slit lamp biomicroscopy was unremarkable. Indirect fundoscopy revealed a left optic nerve head obscured by a darkly pigmented lesion. Fundic examination in the right eye was unremarkable. Magnetic resonance imaging revealed a smoothly marginated, lobulated cone to irregularly shaped, strongly T1 hyperintense, T2 and T2 fluid-attenuated inversion recovery hypointense, strongly contrast enhancing mass closely associated with the entire left optic nerve, extending across the optic chiasm and into the right optic nerve ventrally. Full clinical staging revealed no evidence of metastasis. Exenteration of the left eye was performed. Histopathology revealed an unencapsulated, poorly demarcated, multilobulated and infiltrative pigmented mass that was effacing the posterior choroid and optic nerve. The mass was composed of a moderately pleomorphic population of heavily pigmented polygonal cells arranged in sheets and clusters, displaying moderate anisocytosis and anisokaryosis. The population of cells contained moderate amounts of abundant brown-black granular pigment consistent with melanin within the cytoplasm. Mitotic figures averaged approximately three per ten 400× fields (2.37 mm2 ). This is the first report of a melanocytic tumor invading along the optic nerve and tract to result in contralateral vision loss.


Assuntos
Doenças do Cão , Melanoma , Masculino , Animais , Cães , Melanoma/complicações , Melanoma/veterinária , Melanoma/diagnóstico , Nervo Óptico/patologia , Transtornos da Visão/veterinária , Cegueira/veterinária , Corioide/patologia , Melanoma Maligno Cutâneo
2.
Proc Natl Acad Sci U S A ; 111(1): 445-50, 2014 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-24335589

RESUMO

The discovery and characterization of broadly neutralizing antibodies (bnAbs) against influenza viruses have raised hopes for the development of monoclonal antibody (mAb)-based immunotherapy and the design of universal influenza vaccines. Only one human bnAb (CR8020) specifically recognizing group 2 influenza A viruses has been previously characterized that binds to a highly conserved epitope at the base of the hemagglutinin (HA) stem and has neutralizing activity against H3, H7, and H10 viruses. Here, we report a second group 2 bnAb, CR8043, which was derived from a different germ-line gene encoding a highly divergent amino acid sequence. CR8043 has in vitro neutralizing activity against H3 and H10 viruses and protects mice against challenge with a lethal dose of H3N2 and H7N7 viruses. The crystal structure and EM reconstructions of the CR8043-H3 HA complex revealed that CR8043 binds to a site similar to the CR8020 epitope but uses an alternative angle of approach and a distinct set of interactions. The identification of another antibody against the group 2 stem epitope suggests that this conserved site of vulnerability has great potential for design of therapeutics and vaccines.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Vírus da Influenza A/química , Animais , Anticorpos/química , Anticorpos Monoclonais/química , Anticorpos Neutralizantes/química , Anticorpos Antivirais/química , Cromatografia em Gel , Ensaio de Imunoadsorção Enzimática , Epitopos/química , Feminino , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Humanos , Memória Imunológica , Vacinas contra Influenza/química , Vacinas contra Influenza/imunologia , Cinética , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica , Modelos Moleculares , Conformação Molecular , Especificidade da Espécie
3.
J Virol ; 88(23): 13580-92, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25210195

RESUMO

UNLABELLED: Due to continuous changes to its antigenic regions, influenza viruses can evade immune detection and cause a significant amount of morbidity and mortality around the world. Influenza vaccinations can protect against disease but must be annually reformulated to match the current circulating strains. In the development of a broad-spectrum influenza vaccine, the elucidation of conserved epitopes is paramount. To this end, we designed an immunization strategy in mice to boost the humoral response against conserved regions of the hemagglutinin (HA) glycoprotein. Of note, generation and identification of broadly neutralizing antibodies that target group 2 HAs are rare and thus far have yielded only a few monoclonal antibodies (MAbs). Here, we demonstrate that mouse MAb 9H10 has broad and potent in vitro neutralizing activity against H3 and H10 group 2 influenza A subtypes. In the mouse model, MAb 9H10 protects mice against two divergent mouse-adapted H3N2 strains, in both pre- and postexposure administration regimens. In vitro and cell-free assays suggest that MAb 9H10 inhibits viral replication by blocking HA-dependent fusion of the viral and endosomal membranes early in the replication cycle and by disrupting viral particle egress in the late stage of infection. Interestingly, electron microscopy reconstructions of MAb 9H10 bound to the HA reveal that it binds a similar binding footprint to MAbs CR8020 and CR8043. IMPORTANCE: The influenza hemagglutinin is the major antigenic target of the humoral immune response. However, due to continuous antigenic changes that occur on the surface of this glycoprotein, influenza viruses can escape the immune system and cause significant disease to the host. Toward the development of broad-spectrum therapeutics and vaccines against influenza virus, elucidation of conserved regions of influenza viruses is crucial. Thus, defining these types of epitopes through the generation and characterization of broadly neutralizing monoclonal antibodies (MAbs) can greatly assist others in highlighting conserved regions of hemagglutinin. Here, we demonstrate that MAb 9H10 that targets the hemagglutinin stalk has broadly neutralizing activity against group 2 influenza A viruses in vitro and in vivo.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Animais , Anticorpos Monoclonais/uso terapêutico , Anticorpos Neutralizantes/uso terapêutico , Anticorpos Antivirais/uso terapêutico , Linhagem Celular , Modelos Animais de Doenças , Epitopos/imunologia , Feminino , Glicoproteínas de Hemaglutininação de Vírus da Influenza/uso terapêutico , Humanos , Imunização Passiva , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Transmissão , Infecções por Orthomyxoviridae/prevenção & controle , Infecções por Orthomyxoviridae/terapia , Resultado do Tratamento , Internalização do Vírus/efeitos dos fármacos , Liberação de Vírus/efeitos dos fármacos
4.
J Virol ; 87(22): 12471-80, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24027321

RESUMO

Influenza virus is a global health concern due to its unpredictable pandemic potential. This potential threat was realized in 2009 when an H1N1 virus emerged that resembled the 1918 virus in antigenicity but fortunately was not nearly as deadly. 5J8 is a human antibody that potently neutralizes a broad spectrum of H1N1 viruses, including the 1918 and 2009 pandemic viruses. Here, we present the crystal structure of 5J8 Fab in complex with a bacterially expressed and refolded globular head domain from the hemagglutinin (HA) of the A/California/07/2009 (H1N1) pandemic virus. 5J8 recognizes a conserved epitope in and around the receptor binding site (RBS), and its HCDR3 closely mimics interactions of the sialic acid receptor. Electron microscopy (EM) reconstructions of 5J8 Fab in complex with an HA trimer from a 1986 H1 strain and with an engineered stabilized HA trimer from the 2009 H1 pandemic virus showed a similar mode of binding. As for other characterized RBS-targeted antibodies, 5J8 uses avidity to extend its breadth and affinity against divergent H1 strains. 5J8 selectively interacts with HA insertion residue 133a, which is conserved in pandemic H1 strains and has precluded binding of other RBS-targeted antibodies. Thus, the RBS of divergent HAs is targeted by 5J8 and adds to the growing arsenal of common recognition motifs for design of therapeutics and vaccines. Moreover, consistent with previous studies, the bacterially expressed H1 HA properly refolds, retaining its antigenic structure, and presents a low-cost and rapid alternative for engineering and manufacturing candidate flu vaccines.


Assuntos
Anticorpos Antivirais/imunologia , Antígenos Virais/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Vírus da Influenza A Subtipo H1N1/imunologia , Influenza Humana/imunologia , Pandemias , Receptores Virais/imunologia , Anticorpos Antivirais/metabolismo , Afinidade de Anticorpos , Antígenos Virais/metabolismo , Sítios de Ligação de Anticorpos , Cristalografia por Raios X , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Humanos , Influenza Humana/epidemiologia , Influenza Humana/virologia , Modelos Moleculares , Conformação Proteica , Receptores Virais/metabolismo , Estados Unidos/epidemiologia
5.
Endoscopy ; 45(7): 532-6, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23801313

RESUMO

BACKGROUND AND STUDY AIMS: A dilated gastrojejunal anastomosis (GJA) is thought to be associated with weight regain in patients with Roux-en-Y gastric bypass (RYGB). Due to a high rate of perioperative morbidity, surgical revision is not generally performed. The aim of this study was to assess the technical feasibility, safety, and early outcomes of a procedure using a commercially available endoscopic suturing device to reduce the diameter of the GJA. PATIENTS AND METHODS: This was a retrospective analysis of 25 consecutive patients who underwent transoral outlet reduction (TORe) for dilated GJA and weight regain. An endoscopic suturing device was used to place sutures at the margin of the GJA in order to reduce its aperture. On chart review, clinical data were available at 3, 6, and 12 months. RESULTS: Patients had regained a mean of 24 kg from their weight loss nadir and had a mean body mass index of 43 kg/m2 at the time of endoscopic revision. Average anastomosis diameter was 26.4 mm. Technical success was achieved in all patients (100 %) with a mean reduction in anastomosis diameter to 6 mm (range 3 - 10 mm), representing a 77.3 % reduction. The mean weight loss in successful cases was 11.5 kg, 11.7 kg, and 10.8 kg at 3, 6, and 12 months, respectively. There were no major complications. CONCLUSION: This case series demonstrated the technical feasibility, safety, and efficacy of performing gastrojejunostomy reduction using a commercially available endoscopic suturing device. This technique may represent an effective and minimally invasive option for the management of weight regain in patients with RYGB.


Assuntos
Endoscopia Gastrointestinal/instrumentação , Derivação Gástrica , Obesidade/cirurgia , Técnicas de Sutura/instrumentação , Aumento de Peso , Adulto , Idoso , Estudos de Viabilidade , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Reoperação , Estudos Retrospectivos , Resultado do Tratamento , Redução de Peso
6.
Vet Clin Pathol ; 52(1): 97-101, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35974430

RESUMO

A 9-week-old puppy with refractory seizures and a dome-shaped head presented to the Mississippi State College of Veterinary Medicine Specialty Center for suspected hydrocephalus. Computerized tomography (CT) findings included transtentorial herniation and an intra-axial mass with dystrophic mineralization. Cerebrospinal fluid analysis revealed an increased nucleated cell count of 1100/µl (RI < 5/µl), erythrocyte count of 2.2 × 106 /µl, and markedly increased microprotein of 1939 mg/dl (RI < 30 mg/dl). On cytologic examination of the CSF, numerous erythrophagocytic, and hemosiderin-laden macrophages were observed, which indicated chronic active hemorrhage. Many neutrophils, macrophages, and lymphocytes that contained numerous intracytoplasmic, pleomorphic, bright yellow crystals were observed. Considering the ongoing hemorrhage, the crystals were presumed to be hematoidin. A biopsy with histopathology was performed on the intra-axial mass, and the results were consistent with a vascular hamartoma. We speculate that the formation of these crystals was related to the ongoing hemorrhage associated with the vascular hamartoma. Identification of these crystals may be useful to aid in the identification of chronic hemorrhage associated with vascular malformations or lesions within the central nervous system.


Assuntos
Neoplasias Encefálicas , Doenças do Cão , Hamartoma , Animais , Cães , Neoplasias Encefálicas/veterinária , Citodiagnóstico/veterinária , Contagem de Eritrócitos/veterinária , Hamartoma/veterinária , Micropeptídeos
7.
J Am Chem Soc ; 133(43): 17463-72, 2011 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-21913704

RESUMO

Simulations based on perfectly funneled energy landscapes often capture many of the kinetic features of protein folding. We examined whether simulations based on funneled energy functions can also describe fluctuations in native-state protein ensembles. We quantitatively compared the site-specific local stability determined from structure-based folding simulations, with hydrogen exchange protection factors measured experimentally for ubiquitin, chymotrypsin inhibitor 2, and staphylococcal nuclease. Different structural definitions for the open and closed states based on the number of native contacts for each residue, as well as the hydrogen-bonding state, or a combination of both criteria were evaluated. The predicted exchange patterns agree with the experiments under native conditions, indicating that protein topology indeed has a dominant effect on the exchange kinetics. Insights into the simplest mechanistic interpretation of the amide exchange process were thus obtained.


Assuntos
Medição da Troca de Deutério , Nuclease do Micrococo/química , Peptídeos/química , Proteínas de Plantas/química , Ubiquitina/química , Humanos , Nuclease do Micrococo/metabolismo , Modelos Moleculares , Conformação Proteica , Dobramento de Proteína , Termodinâmica
8.
Endoscopy ; 43(5): 394-9, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21425041

RESUMO

BACKGROUND AND STUDY AIMS: Endoscopic ultrasound (EUS) is a complex procedure due to the subtleties of ultrasound interpretation, the small field of observation, and the uncertainty of probe position and orientation. Animal studies demonstrated that Image Registered Gastroscopic Ultrasound (IRGUS) is feasible and may be superior to conventional EUS in efficiency and image interpretation. This study explores whether these attributes of IRGUS will be evident in human subjects, with the aim of assessing the feasibility, effectiveness, and efficiency of IRGUS in patients with suspected pancreatic lesions. PATIENTS AND METHODS: This was a prospective feasibility study at a tertiary care academic medical center in human patients with pancreatic lesions on computed tomography (CT) scan. Patients who were scheduled to undergo conventional EUS were randomly chosen to undergo their procedure with IRGUS. Main outcome measures included feasibility, ease of use, system function, validated task load (TLX) assessment instrument, and IRGUS experience questionnaire. RESULTS: Five patients underwent IRGUS without complication. Localization of pancreatic lesions was accomplished efficiently and accurately (TLX temporal demand 3.7 %; TLX effort 8.6 %). Image synchronization and registration was accomplished in real time without procedure delay. The mean assessment score for endoscopist experience with IRGUS was positive (66.6 ± 29.4). Real-time display of CT images in the EUS plane and echoendoscope orientation were the most beneficial characteristics. CONCLUSIONS: IRGUS appears feasible and safe in human subjects, and efficient and accurate at identification of probe position and image interpretation. IRGUS has the potential to broaden the adoption of EUS techniques and shorten EUS learning curves. Clinical studies comparing IRGUS with conventional EUS are ongoing.


Assuntos
Endossonografia/métodos , Pancreatopatias/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Endoscopia do Sistema Digestório/métodos , Estudos de Viabilidade , Feminino , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Masculino , Pessoa de Meia-Idade , Pancreatopatias/diagnóstico , Projetos Piloto , Estudos Prospectivos
9.
Biochemistry ; 48(24): 5541-52, 2009 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-19419198

RESUMO

The calmodulin antagonist W7 binds to troponin C in the presence of Ca(2+) and inhibits striated muscle contraction. This study integrates multiple data into the structure of the regulatory domain of human cardiac troponin C (cNTnC) bound to Ca(2+) and W7. The protein-W7 interface is defined through a three-dimensional {(1)H,(13)C}-edited-{(1)H,(12)C}-detected NOESY NMR experiment, and other aspects of the structure are modeled as perturbations to previously known coordinates and restraints. The structure determination protocol optimizes the protein-W7 contacts prior to the introduction of protein-W7 steric interactions or conformational changes in the protein. The structure determination protocol gives families of conformers that all have an optimal docking as assessed by satisfaction of the target function. The structure supports the previously proposed troponin I blocking mechanism for the activity of W7 in striated muscle and suggests a role for the flexible tail of W7 in stabilization of the bound state. This clarifies the structure-activity relationships of W7 and implicates an electrostatically mediated component of activity in common analogues of W7, including the antipsychotic trifluoroperazine and the cardiotonic levosimendan.


Assuntos
Inibidores Enzimáticos/química , Sulfonamidas/química , Troponina C/química , Cristalografia por Raios X , Inibidores Enzimáticos/metabolismo , Humanos , Modelos Moleculares , Conformação Proteica , Estrutura Terciária de Proteína , Relação Estrutura-Atividade , Sulfonamidas/metabolismo , Troponina C/metabolismo
10.
Br J Sports Med ; 43(4): 303-6, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19019908

RESUMO

OBJECTIVE: To report on the effectiveness of sonographically guided injections of hyperosmolar dextrose at reducing the pain associated with chronic plantar fasciitis. DESIGN: Case series. SETTING: Ultrasound division of St Paul's Hospital. PATIENTS: 20 referrals (3 men, 17 women; age 51 (SD 13) years) from local sports medicine primary care practitioners who had failed previous conservative treatments. INTERVENTIONS: A 27-gauge needle administered a 25% dextrose/lidocaine solution under sonographic guidance at 6 week intervals returning for a median of three consultations. MAIN OUTCOME MEASURES: Visual analogue scale (VAS) items for pain levels at rest (VAS1), activities of daily living (VAS2), and during or after physical activity (VAS3) were recorded at baseline and at the final treatment consultation (post-test). A telephone interview conducted an average of 11.8 months after the post-test consultation provided a measure of long-term follow-up. RESULTS: 16 patients reported a good to excellent outcome, while the symptoms in 4 patients were unchanged. There was a significant decrease (p<0.001) in all mean VAS items from pre-test to post-test: VAS1 (36.8 (SD 25.6) to 10.3 (10.9)), VAS2 (74.7 (20.8) to 25.0 (27.7)) and VAS3 (91.6 (9.2) to 38.7 (35.1)) and there were no apparent changes after the follow-up interview. CONCLUSIONS: Sonographically guided dextrose injections showed a good clinical response in patients with chronic plantar fasciitis insofar as pain was reduced during rest and activity. Further studies including a control group are needed to validate these outcomes.


Assuntos
Anestésicos Locais/administração & dosagem , Fasciíte Plantar/tratamento farmacológico , Glucose/administração & dosagem , Lidocaína/administração & dosagem , Ultrassonografia de Intervenção/métodos , Adulto , Fasciíte Plantar/diagnóstico por imagem , Feminino , Humanos , Injeções/métodos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Estudos Prospectivos , Resultado do Tratamento
11.
Proteins ; 73(2): 338-50, 2008 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-18433059

RESUMO

Various intrinsic disorder (ID) prediction algorithms were applied to the three tissue isoforms of troponin I (TnI). The results were interpreted in terms of the known structure and dynamics of troponin. In line with previous results, all isoforms of TnI were predicted to have large stretches of ID. The predictions show that the C-termini of all isoforms are extensively disordered as is the N-terminal extension of the cardiac isoform. Cardiac TnI likely belongs to the group of intrinsically disordered signalling hub proteins. For a given portion of the protein sequence, most ID prediction approaches indicate isoform-dependent variations in the probability of disorder. Comparison of machine learning and physically based approaches suggests the ID variations are only partially attributable to local variations in the ratio of charged to hydrophobic residues. The VSL2B algorithm predicts the largest variations in ID across the isoforms, with the cardiac isoform having the highest probability of structured regions, and the fast-skeletal isoform having no intrinsic structure. The region corresponding to residues 57-95 of the fast-skeletal isoform, known to form a coiled coil substructure with troponin T, was highly variable between isoforms. The isoform-specific ID variations may have mechanistic significance, modulating the extent to which conformational fluctuations in tropomyosin are communicated to the troponin complex. We discuss structural mechanisms for this communication. Overall, the results motivate the development of predictors designed to address relative levels of disorder between highly similar proteins.


Assuntos
Cálcio/metabolismo , Fibras Musculares de Contração Rápida/metabolismo , Miocárdio/metabolismo , Tropomiosina/metabolismo , Troponina I/metabolismo , Sequência de Aminoácidos , Animais , Humanos , Dados de Sequência Molecular , Isoformas de Proteínas/metabolismo , Alinhamento de Sequência , Troponina I/química
12.
Science ; 362(6414): 598-602, 2018 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-30385580

RESUMO

Broadly neutralizing antibodies against highly variable pathogens have stimulated the design of vaccines and therapeutics. We report the use of diverse camelid single-domain antibodies to influenza virus hemagglutinin to generate multidomain antibodies with impressive breadth and potency. Multidomain antibody MD3606 protects mice against influenza A and B infection when administered intravenously or expressed locally from a recombinant adeno-associated virus vector. Crystal and single-particle electron microscopy structures of these antibodies with hemagglutinins from influenza A and B viruses reveal binding to highly conserved epitopes. Collectively, our findings demonstrate that multidomain antibodies targeting multiple epitopes exhibit enhanced virus cross-reactivity and potency. In combination with adeno-associated virus-mediated gene delivery, they may provide an effective strategy to prevent infection with influenza virus and other highly variable pathogens.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Camelídeos Americanos/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Vírus da Influenza A/imunologia , Vírus da Influenza B/imunologia , Vacinas contra Influenza/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Animais , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/ultraestrutura , Anticorpos Antivirais/química , Anticorpos Antivirais/ultraestrutura , Cristalografia por Raios X , Cães , Feminino , Epitopos Imunodominantes/química , Epitopos Imunodominantes/genética , Epitopos Imunodominantes/imunologia , Células Madin Darby de Rim Canino , Camundongos , Camundongos Endogâmicos BALB C , Testes de Neutralização , Biblioteca de Peptídeos , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Anticorpos de Domínio Único
13.
J Mol Biol ; 361(4): 625-33, 2006 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-16876196

RESUMO

The troponin (Tn) complex regulates the thin filament of striated muscle by transducing [Ca2+] fluctuations into conformational changes. These changes propagate to tropomyosin (Tm), which then assumes a new disposition with respect to actin, reversibly exposing actin's binding sites for the thick filament motor-ATPase (myosin). To date, the structural biology of thin filament regulation has been studied in the context of two equilibrium states corresponding to high (contraction-activated) and low (contraction-inhibited) sarcomeric [Ca2+]. New electron micrographic reconstructions of the thin filament have resolved Tn, actin, and Tm in high and low [Ca2+] states, integrating high-resolution structures of the Tn core, actin, and Tm. The resultant picture of thin filament regulation does not resolve all of the functionally significant portions of troponin I (TnI) or troponin C (TnC). Those regions of Tn have been shown (using NMR relaxation spectroscopy) to undergo conformational fluctuations, rationalizing the absence of these regions from micrograph-based reconstructions. The disordered portions of Tn are, to date, being interpreted within a canonical structure-activity paradigm. Here we present a new mechanism for the regulation of Tn having explicit descriptions of the kinetic pathways of activation and inhibition. Our thesis is that the intrinsic disorder of TnI is mechanistically significant. As the coupling of folding to binding has been shown to confer an inherent kinetic advantage (known as flycasting activity), our thesis accounts for TnI's conformational heterogeneity and known structure-activity relationships in a parsimonious fashion. We integrate recent NMR structures of the C-terminus of TnI and NMR observations of the conformational dynamics of the Tn complex into high-resolution models of the thin filament. Ways of evaluating the mechanism are discussed. The novel conceptual framework presented here prompts new hypotheses regarding the mechanism of pH sensitivity and of pathogenic mutations in troponin.


Assuntos
Cálcio/metabolismo , Músculo Esquelético/metabolismo , Troponina/química , Cardiomiopatias/metabolismo , Concentração de Íons de Hidrogênio , Cinética , Modelos Moleculares , Ressonância Magnética Nuclear Biomolecular , Ligação Proteica , Conformação Proteica , Dobramento de Proteína , Troponina/metabolismo
14.
J Natl Cancer Inst ; 86(9): 673-80, 1994 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-8158698

RESUMO

BACKGROUND: Patients with resectable stage IIIA non-small-cell lung cancer have a low survival rate following standard surgical treatment. Nonrandomized trials in which induction chemotherapy or a combination of chemotherapy and radiation prior to surgery were used to treat patients with regionally advanced primary cancers have suggested that survival is improved when compared with treatment by surgery alone. PURPOSE: We performed a prospective, randomized study of patients with previously untreated, potentially resectable clinical stage IIIA non-small-cell lung cancer to compare the results of perioperative chemotherapy and surgery with those of surgery alone. METHODS: This trial was designed to test the null hypothesis that the proportion of patients surviving 3 years is 12% for either treatment group against the alternate hypothesis that the 3-year survival rate would be 12% in the surgery alone group and 32% in the perioperative chemotherapy group. The estimated required sample size was 65 patients in each group. The trial was terminated at an early time according to the method of O'Brien and Fleming following a single unplanned interim analysis. The decision to terminate the trial was based on ethical considerations, the magnitude of the treatment effect, and the high degree of statistical significance attained. In total, 60 patients were randomly assigned between 1987 and 1993 to receive either six cycles of perioperative chemotherapy (cyclophosphamide, etoposide, and cisplatin) and surgery (28 patients) or surgery alone (32 patients). For patients in the former group, tumor measurements were made before each course of chemotherapy and the clinical tumor response was evaluated after three cycles of chemotherapy; they then underwent surgical resection. Patients who had documented tumor regression after preoperative chemotherapy received three additional cycles of chemotherapy after surgery. RESULTS: After three cycles of preoperative chemotherapy, the rate of clinical major response was 35%. Patients treated with perioperative chemotherapy and surgery had an estimated median survival of 64 months compared with 11 months for patients who had surgery alone (P < .008 by log-rank test; P < .018 by Wilcoxon test). The estimated 2- and 3-year survival rates were 60% and 56% for the perioperative chemotherapy patients and 25% and 15% for those who had surgery alone, respectively. CONCLUSIONS: In this trial, the treatment strategy using perioperative chemotherapy and surgery was more effective than surgery alone. IMPLICATIONS: This clinical trial strengthens the validity of using perioperative chemotherapy in the management of patients with resectable stage IIIA non-small-cell lung cancer. Further investigation of the perioperative chemotherapy strategy in earlier stage lung cancer is warranted.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma Pulmonar de Células não Pequenas/cirurgia , Quimioterapia Adjuvante , Cisplatino/administração & dosagem , Ciclofosfamida/administração & dosagem , Epirubicina/administração & dosagem , Feminino , Humanos , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/cirurgia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Estudos Prospectivos , Indução de Remissão , Estatística como Assunto , Análise de Sobrevida , Fatores de Tempo , Resultado do Tratamento
15.
J Clin Oncol ; 11(1): 22-8, 1993 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8418237

RESUMO

PURPOSE: The curative resection rate in patients with potentially resectable carcinoma of the esophagus is approximately 55% and their median survival time is 11 months. Preoperative chemotherapy with high doses of chemotherapeutic agents was used to evaluate clinical and pathologic responses, curative resection rate, toxicity, and survival. Colony-stimulating factor (CSF) was added to reduce the severity of myelosuppression. PATIENTS AND METHODS: Twenty-six consecutive assessable patients with potentially resectable adenocarcinoma of the esophagus or gastroesophageal junction were treated with two preoperative courses of intensive chemotherapy (etoposide, doxorubicin, and cisplatin [EAP]) with granulocyte-macrophage CSF (GM-CSF). Additional three conventional-dose postoperative chemotherapy courses without GM-CSF were given to patients who responded to preoperative chemotherapy. RESULTS: A median of three courses (range, one to six), were administered. Of 27 patients, 26 were assessable for response to preoperative EAP; 13 (50%) achieved a major response. Among 23 patients who underwent surgery, 15 (65%) had a curative resection (58% of 26 assessable patients); none of the patients had a pathologic complete response, but two patients had only microscopic carcinoma in the resected specimen. Six patients had carcinoma present at the resection margins and received postoperative radiotherapy. Two patients were found to have liver metastases at exploration. At a median follow-up of 22 months, the median survival of 26 patients was 12.5 months (range, 2 to 32 +). Fourteen patients died of their carcinoma; two patients died of treatment-related causes; one died of an unrelated CNS arterial malformation; and the causes of death in two patients remain unknown. Seven patients are alive with no evidence of relapse. Major toxicities of this regimen included severe myelosuppression, nausea and vomiting, infections, and severe constitutional symptoms related to GM-CSF. However, subcutaneous injection of GM-CSF was well tolerated. CONCLUSION: High-dose EAP is active against locoregional adenocarcinoma of the esophagus and gastroesophageal junction but can be associated with significant toxicity. Although this strategy remains attractive and needs to be developed further, less toxic and more effective regimens need to be identified.


Assuntos
Adenocarcinoma/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Doenças da Medula Óssea/prevenção & controle , Neoplasias Esofágicas/tratamento farmacológico , Junção Esofagogástrica , Fator Estimulador de Colônias de Granulócitos e Macrófagos/uso terapêutico , Adenocarcinoma/cirurgia , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Doenças da Medula Óssea/induzido quimicamente , Quimioterapia Adjuvante , Cisplatino/administração & dosagem , Doxorrubicina/administração & dosagem , Esquema de Medicação , Neoplasias Esofágicas/cirurgia , Junção Esofagogástrica/cirurgia , Etoposídeo/administração & dosagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Sobrevida , Resultado do Tratamento
16.
Science ; 349(6254): 1301-6, 2015 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-26303961

RESUMO

The identification of human broadly neutralizing antibodies (bnAbs) targeting the hemagglutinin (HA) stem revitalized hopes of developing a universal influenza vaccine. Using a rational design and library approach, we engineered stable HA stem antigens ("mini-HAs") based on an H1 subtype sequence. Our most advanced candidate exhibits structural and bnAb binding properties comparable to those of full-length HA, completely protects mice in lethal heterologous and heterosubtypic challenge models, and reduces fever after sublethal challenge in cynomolgus monkeys. Antibodies elicited by this mini-HA in mice and nonhuman primates bound a wide range of HAs, competed with human bnAbs for HA stem binding, neutralized H5N1 viruses, and mediated antibody-dependent effector activity. These results represent a proof of concept for the design of HA stem mimics that elicit bnAbs against influenza A group 1 viruses.


Assuntos
Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Vírus da Influenza A Subtipo H1N1/imunologia , Virus da Influenza A Subtipo H5N1/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/prevenção & controle , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Humanos , Camundongos , Multimerização Proteica , Estrutura Secundária de Proteína
17.
Eur J Cancer ; 31A(5): 665-70, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-7640036

RESUMO

The purpose of this study was to examine the feasibility of administering all chemotherapy pre-operatively to patients with resectable adenocarcinoma of the oesophagus or gastrooesophageal junction. 32 patients with potentially resectable adenocarcinoma of the oesophagus or gastrooesophageal junction were studied in a stepwise fashion in which combination chemotherapy with cisplatin, high-dose arabinoside and 5-fluorouracil was administered. In the first part, 15 patients were to receive three chemotherapy courses pre-operatively and two chemotherapy courses postoperatively. In the second part, the next 15 patients were to receive all five chemotherapy courses pre-operatively, provided there was an objective response after three courses. Endoscopic ultrasonography was also performed, when feasible, prior to chemotherapy and surgery, and in some patients sequentially between chemotherapy courses. All of the 14 assessable patients in the first group tolerated all three courses of pre-operative chemotherapy, and 86% of patients in this group completed all protocol chemotherapy. In the second group, 9 of 18 (50%) assessable patients tolerated all five courses of preoperative chemotherapy, and 100% of patients in this group received all protocol chemotherapy. The median number of chemotherapy courses for the entire group (32 patients) was five (range one to five). Forty-one per cent (13/32) of patients had a major response to chemotherapy. Sixty-nine per cent (or 76% of 29 patients taken to surgery) had a curative resection. One patient had a pathological complete response. The median survival time of 32 patients was 17 months (range 2-36+ months). 14 patients (37%) remain alive at a median follow-up time of 26+ months. There was a correlation between endoscopic ultrasonographic tumour and nodal stage and pathological tumour and nodal stages in 16 patients. The tumour stage correlation was higher (75%) than the nodal stage correlation (62%). Our data suggest that it is feasible to administer five courses of cisplatin-based chemotherapy to patients with potentially resectable adenocarcinoma of the oesophagus or gastrooesophageal junction. More effective chemotherapy regimens that might result in higher pathological complete response rates and acceptable toxic effects are needed.


Assuntos
Adenocarcinoma/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Esofágicas/tratamento farmacológico , Pré-Medicação , Neoplasias Gástricas/tratamento farmacológico , Adenocarcinoma/diagnóstico por imagem , Adenocarcinoma/mortalidade , Adenocarcinoma/cirurgia , Adulto , Idoso , Cisplatino/administração & dosagem , Terapia Combinada , Citarabina/administração & dosagem , Esquema de Medicação , Neoplasias Esofágicas/diagnóstico por imagem , Neoplasias Esofágicas/mortalidade , Neoplasias Esofágicas/cirurgia , Feminino , Fluoruracila/administração & dosagem , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Gástricas/diagnóstico por imagem , Neoplasias Gástricas/mortalidade , Neoplasias Gástricas/cirurgia , Taxa de Sobrevida , Ultrassonografia
18.
Int J Radiat Oncol Biol Phys ; 23(2): 397-400, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1587762

RESUMO

Between November 1988 and March 1990, 24 patients with endobronchial tumors that had recurred after external beam radiation therapy were treated with high dose rate intraluminal irradiation. A remote afterloading high dose rate unit was used, and most patients received two endobronchial treatments, separated by a two week interval. All patients were given the same dose and dose specification to assess the feasibility and complications of the therapy. At each treatment, 15 Gy were delivered with dose specified at a radius of 6 mm from the center of the source, which corresponds to a dose of 9 Gy at a radius of 1 cm. Overall, 21 of 24 patients (88%) showed good symptomatic improvement. Of 18 patients whose chest x-ray showed evidence of collapse or atelectasis caused by tumor obstruction, 15 (83%) had evidence of reaeration. The median duration of palliation, marked by symptoms or a chest x-ray that worsened, was 26 weeks, the range varying from seven to 40 weeks. No patient died as a result of therapy and only one had a complication, bronchospasm, which responded well to bronchodilators. One patient died of hemoptysis approximately three months after treatment. Five additional patients, who were treated off protocol because they had an Eastern Cooperative Oncology Group performance status of greater than two, also received endobronchial irradiation. All five died within one month from worsening pulmonary disease, and we do not recommend endobronchial irradiation for patients with an Eastern Cooperative Oncology Group performance status of greater than two. We conclude that high dose rate endobronchial brachytherapy effectively relieves the symptoms of endobronchial obstruction due to recurrent lung cancer and can be given safely as an outpatient procedure. As the complications were minimal in this series treated with a uniform dose of 15 Gy per treatment, future studies should aim at determining the maximum tolerated dose. This technique may also be helpful as a boost after maximal external beam irradiation or to open up areas of atelectasis prior to external beam irradiation.


Assuntos
Braquiterapia/métodos , Carcinoma Broncogênico/radioterapia , Neoplasias Pulmonares/radioterapia , Recidiva Local de Neoplasia/radioterapia , Adulto , Idoso , Braquiterapia/instrumentação , Carcinoma Broncogênico/epidemiologia , Feminino , Humanos , Radioisótopos de Irídio/uso terapêutico , Neoplasias Pulmonares/epidemiologia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/epidemiologia , Estudos Prospectivos , Taxa de Sobrevida
19.
Chest ; 101(2): 356-61, 1992 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-1735254

RESUMO

Exercise testing was performed on 37 patients with resectable lung lesions who were deemed inoperable because of any of the following risk factors: (1) FEV1 less than or equal to 40 percent of predicted; (2) radionuclide calculated postlobectomy FEV1 less than or equal to 33 percent of predicted; or (3) arterial PCO2 greater than or equal to 45 mm Hg. The patients who reached a peak level of oxygen consumption during exercise (VO2Peak) of greater than or equal to 15 ml/kg/min were offered surgical treatment. Patients with a VO2Peak of less than 15 ml/kg/min were referred for nonsurgical management and excluded from the study. Eight patients underwent lung resection. Their pulmonary function revealed a severe obstructive lung defect with a group mean predicted FEV1 of 40 +/- 6 percent, an FEV1/FVC ratio of 47 +/- 10, a radionuclide calculated postlobectomy FEV1 of 31 +/- 4 percent, and a mean arterial PCO2 of 44 +/- 6 mm Hg. No relationship was found between each patient's exercise performance and spirometric function. Six of the patients had an uncomplicated postoperative course. Two patients had complications but no patient died as a result of surgery or postoperative complications. All patients were discharged from the hospital within 22 days (mean = 9.8 days). We conclude that exercise testing is a useful complement to conventional cardiopulmonary evaluation used in selecting patients for lung resection.


Assuntos
Teste de Esforço , Pneumonectomia/efeitos adversos , Testes de Função Respiratória , Idoso , Feminino , Volume Expiratório Forçado , Humanos , Pulmão/diagnóstico por imagem , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/fisiopatologia , Neoplasias Pulmonares/cirurgia , Masculino , Pessoa de Meia-Idade , Cintilografia , Fatores de Risco , Capacidade Pulmonar Total , Relação Ventilação-Perfusão , Capacidade Vital
20.
Ann Thorac Surg ; 57(2): 319-25, 1994 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8311591

RESUMO

Residency training programs commonly emphasize a single technique of esophagectomy, as the safety and the efficacy of teaching or performing more than one type of esophagectomy are unclear. Between 1986 and 1992, 248 patients were explored for possible esophageal resection. Thoracic surgical residents or fellows performed major components of all resections. Two hundred twenty-one patients (adenocarcinoma, 146; squamous cell carcinoma, 72; and other, 3) underwent transthoracic esophagectomy (n = 134), transhiatal esophagectomy (n = 42), or total thoracic esophagectomy (n = 45), a resectability rate of 89.1% (221/248). Complications occurred in 75% of patients with transthoracic esophagectomy, in 69% with transhiatal esophagectomy, and in 80% with total thoracic esophagectomy. The overall operative mortality rate was 6.8% (15/221). Patients with a cervical anastomosis had a higher leak rate (13%) than those with an intrathoracic anastomosis (6%). Median survival was 22 months (19% 5-year survival) and did not differ by operation type or stage. No patient with unresectable disease (n = 27) survived longer than 10 months. Survival for patients with adenocarcinoma stages 3 and 2a suggested a trend toward improved survival after transthoracic esophagectomy despite similar rates of local and distant recurrence. Transthoracic esophagectomy, transhiatal esophagectomy, and total thoracic esophagectomy performed within a residency training program have similar morbidity, mortality, and recurrence rates as those in other modern series. A specific technique of esophagectomy can be selected for individual patients. Survival and sites of recurrence primarily reflect disease stage, not the technique of esophagectomy used.


Assuntos
Adenocarcinoma/cirurgia , Carcinoma de Células Escamosas/cirurgia , Neoplasias Esofágicas/cirurgia , Esofagectomia/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Esofagectomia/mortalidade , Feminino , Humanos , Internato e Residência , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Complicações Pós-Operatórias/etiologia , Análise de Sobrevida , Cirurgia Torácica/educação
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