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1.
Rev Sci Instrum ; 83(8): 084901, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22938323

RESUMO

A low-voltage (mV) electronically triggered spot welding system for fabricating fine thermocouples and thin sheets used in high-temperature characterization of materials' properties is suggested. The system is based on the capacitance discharge method with a timed trigger for obtaining reliable and consistent welds. In contrast to existing techniques based on employing high voltage DC supplies for charging the capacitor or supplies with positive and negative rails, this method uses a simple, standard dual power supply available at most of the physical laboratories or can be acquired at a low cost. In addition, an efficient and simple method of fabricating non-sticking electrodes that do not contaminate the weld area is suggested and implemented.

2.
Surf Interface Anal ; 44(5): 882-889, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23430137

RESUMO

Increasingly, it is recognized that understanding and predicting nanoparticle behavior is often limited by the degree to which the particles can be reliably produced and adequately characterized. Two examples that demonstrate how sample preparation methods and processing history may significantly impact particle behavior are: 1) an examination of cerium oxide (ceria) particles reported in the literature in relation to the biological responses observed and 2) observations related that influence synthesis and aging of ceria nanoparticles. Examining data from the literature for ceria nanoparticles suggests that thermal history is one factor that has a strong influence on biological impact. Thermal processing may alter many physicochemical properties of the particles, including density, crystal structure, and the presence of surface contamination. However, these properties may not be sufficiently recorded or reported to determine the ultimate source of an observed impact. A second example shows the types of difficulties that can be encountered in efforts to apply a well-studied synthesis route to producing well-defined particles for biological studies. These examples and others further highlight the importance of characterizing particles thoroughly and recording details of particle processing and history that too often are underreported.

3.
Pediatr Dermatol ; 23(5): 497-9, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17014651

RESUMO

We report three teenaged Caucasian patients with confluent and reticulated papillomatosis whose presentation was atypical due to the absence of hyperpigmentation and presence of a fine white scale.


Assuntos
Papiloma/patologia , Neoplasias Cutâneas/patologia , Adolescente , Adulto , Feminino , Humanos , Masculino
4.
Med Teach ; 27(3): 219-33, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-16011945

RESUMO

New medical graduates in the UK are known as Preregistration House Officers (PRHOs). At the end of this first postgraduate year, the Postgraduate Dean is responsible for allowing the PRHO to be fully registered with the General Medical Council. During the period 1999-2002 Professor Miriam Friedman Ben-David designed a more robust approach to appraisal and assessment of PRHOs, which provided educational feedback to all trainees, allowed any poor performers to be detected at an early stage, and provided 'hard' observable evidence for certification decisions. This paper describes the more recent development of her work resulting from further piloting of her system. The key tool, a 360 degrees diagnostic questionnaire, is designed to identify strengths and weaknesses in individual performance. It is presently being used as a screening tool to identify any trainees needing additional support and further assessment. The tool also forms part of an evidence trail for all PRHOs and helps inform formative assessment as well as contributing, along with other evidence, to full registration decisions. The evaluation of this tool, also described in this paper, shows the feasibility of implementing such a system on a wider scale and illustrates the successful balance made between robustness and feasibility.


Assuntos
Competência Clínica , Avaliação de Desempenho Profissional/métodos , Médicos , Atitude do Pessoal de Saúde , Humanos , Relações Interprofissionais , Relações Médico-Paciente
5.
AIDS Care ; 16(5): 586-93, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15223528

RESUMO

This study set out to ascertain what proportion of HIV-positive heterosexual men cared for at a central London teaching hospital HIV medical unit, were referred to the Psychological Medicine Unit, and to compare those HIV-positive male heterosexual patients with age and sex matched HIV-positive gay male controls. Hospital and Psychological Medicine Unit databases were interrogated to identify relevant patients seen during the period between February 1992 and December 2002. Furthermore, 50 heterosexual patients, who had been referred to the Psychological Medicine Unit, were matched for age and date of referral, with one gay male HIV-positive control patient. Demographic and illness data was gathered for the subjects and controls. Data was collected on 50 subjects in each group. The main findings of the study were: (1) that heterosexual men with HIV are almost three times less likely to be referred for specialist mental health care than HIV-positive gay men; (2) that heterosexual men with HIV disease, who were referred to the Psychological Medicine Unit, were less likely to be from a white ethnic background compared to gay men; (3) were less likely to be given a diagnosis of a depressive illness; but (4) were more likely to have a substance misuse diagnosis. Gay male patients who are HIV-positive are more likely to experience difficulties with sexual dysfunction, and receive a formal psychiatric diagnosis. The implications of the findings are discussed.


Assuntos
Infecções por HIV/psicologia , Necessidades e Demandas de Serviços de Saúde/normas , Heterossexualidade/psicologia , Estudos de Casos e Controles , Homossexualidade/psicologia , Hospitais de Ensino , Humanos , Londres , Masculino , Encaminhamento e Consulta/estatística & dados numéricos , Estudos Retrospectivos
6.
J Biol Chem ; 279(19): 20369-77, 2004 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-14990586

RESUMO

Death domain-associated protein (Daxx) is a multi-functional protein that modulates both apoptosis and transcription. Within the nucleus, Daxx is a component of the promyelocytic leukemia protein (PML) nuclear bodies (NBs) and interacts with a number of transcription factors, yet its precise role in transcription remains elusive. To further define the function of Daxx, we have isolated its interacting proteins in the nucleus using epitope-tagged affinity purification and identified X-linked mental retardation and alpha-thalassaemia syndrome protein (ATRX), a putative member of the SNF2 family of ATP-dependent chromatin remodeling proteins that is mutated in several X-linked mental retardation disorders. We show that substantial amounts of endogenous Daxx and ATRX exist in a nuclear complex. Daxx binds to ATRX through its paired amphipathic alpha helices domains. ATRX has ATPase activity that is stimulated by mononucleosomes, and patient mutations in the ATPase domain attenuate this activity. ATRX strongly represses transcription when tethered to a promoter. Daxx does not affect the ATPase activity of ATRX, however, it alleviates its transcription repression activity. In addition, ATRX is found in the PML-NBs, and this localization is mediated by Daxx. These results show that the ATRX.Daxx complex is a novel ATP-dependent chromatin-remodeling complex, with ATRX being the core ATPase subunit and Daxx being the targeting subunit. Moreover, the localization of ATRX to the PML-NBs supports the notion that these structures may play an important role in transcription regulation.


Assuntos
Proteínas de Transporte/fisiologia , DNA Helicases , Proteínas de Ligação a DNA/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular , Proteínas Nucleares/fisiologia , Fatores de Transcrição/fisiologia , Transcrição Genética , Proteínas Adaptadoras de Transdução de Sinal , Adenosina Trifosfatases/química , Trifosfato de Adenosina/química , Sequência de Aminoácidos , Proteínas de Transporte/química , Linhagem Celular , Núcleo Celular/metabolismo , Cromatina/metabolismo , Cromatografia em Gel , Proteínas Correpressoras , DNA/química , Proteínas de Ligação a DNA/química , Relação Dose-Resposta a Droga , Epitopos/química , Deleção de Genes , Regulação da Expressão Gênica , Genes Reporter , Células HeLa , Humanos , Microscopia de Fluorescência , Modelos Biológicos , Chaperonas Moleculares , Dados de Sequência Molecular , Mutação , Proteínas Nucleares/química , Plasmídeos/metabolismo , Testes de Precipitina , Ligação Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Fatores de Transcrição/química , Proteína Nuclear Ligada ao X
8.
Scott Med J ; 49(4): 133-6, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15648705

RESUMO

BACKGROUND AND AIMS: To conduct a profile audit of three surgical treatments for urinary stress incontinence through the application of an episode costing process. METHODS: Four stage methodology: (1) construction or a profile of care for each of the surgical approaches (setting the standard); 2) calculation of a theoretical profile cost; (3) calculation of the observed costs from real patient episodes; (4) comparison of observed costs with profile costs, (comparing present practice with established standard). RESULTS: Profiles of care were constructed and compared with 39 actual in-patient episodes. Tension free vaginal tape (TVT Gynecare) is the cheapest modality of treatment in terms of both the expected profile cost and also observed (real patient) cost. Colposuspension is the most expensive form of treatment with real costs significantly greater than the expected profile. Clinical issues such as length of stay, duration of surgery, patient selection and complication rates were revealed through the exception reporting process. Length of stay is the main determinant of overall cost. CONCLUSION: It is possible to construct a costed and auditable standard of care for a surgical procedure. This standard can be compared with real patient costs calculated using the same methodology. Exception reporting based on differences between expected and real costs can be used to facilitate the audit of clinical practice. The technique is limited, however, by the need to collect accurate and detailed activity data.


Assuntos
Incontinência Urinária por Estresse/economia , Colágeno/uso terapêutico , Custos e Análise de Custo/métodos , Feminino , Humanos , Auditoria Médica , Pessoa de Meia-Idade , Incontinência Urinária por Estresse/cirurgia
9.
Eye (Lond) ; 17(2): 221-7, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12640410

RESUMO

OBJECTIVES: There is evidence that pars plana vitrectomy (PPV) has a beneficial effect on the clinical course of chronic endogenous posterior uveitis (EPU) possibly by physically removing any resident inflammatory cells with the vitreous. We assessed the anatomical and therapeutic effects of PPV performed on patients with chronic EPU for any indication. PATIENTS AND METHODS: Retrospective review of 41 eyes of 38 consecutive patients with EPU who underwent a PPV for any reason, over a 5-year period. The mean age of the patients was 36.2 years, 46% of the eyes had intermediate uveitis, 32% panuveitis, and 22% posterior uveitis. The visual acuity, disease activity, and the requirement for medications to control it were recorded for 12 months pre- and postoperatively. RESULTS: Overall, 61% of the eyes gained more than 2 Snellen lines (P<0.001) and the incidence of cystoid macular oedema (CMO) significantly reduced from 44 to 20% (P<0.05). Postoperatively, there was a significant decrease in the recurrence rate of intermediate uveitis, posterior uveitis, and panuveitis (P<0.001). The use of systemic and local depot immunosuppressive agents did not change over the study period, although the use of topical agents increased (P<0.05). CONCLUSION: PPV appears to have a beneficial effect on the clinical course of EPU in selected cases. This may be mediated by the physical clearance of inflammatory debris, the anti-inflammatory effect of replacing vitreous by aqueous humour, by a reduction of CMO and/or the anatomical correction of sight-threatening retinal pathology.


Assuntos
Uveíte Posterior/cirurgia , Vitrectomia , Adolescente , Adulto , Idoso , Criança , Doença Crônica , Feminino , Humanos , Imunossupressores/uso terapêutico , Masculino , Pessoa de Meia-Idade , Descolamento Retiniano/fisiopatologia , Descolamento Retiniano/cirurgia , Estudos Retrospectivos , Resultado do Tratamento , Uveíte Posterior/tratamento farmacológico , Uveíte Posterior/fisiopatologia , Acuidade Visual
10.
J Med Chem ; 46(3): 399-408, 2003 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-12540239

RESUMO

The design of rigid cyclic analogues derived from cinnamamide 1, (E)-N-cyclopropyl-3-(3-fluorophenyl)prop-2-enamide, and beta-methylcinnamamide 2, (E)-N-cyclopropyl-3-(3-fluorophenyl)but-2-enamide, has led to the discovery of the potent, centrally acting muscle relaxant (E)-2-(4,6-difluoro-1-indanylidene)acetamide, 17. Compound 17 also possesses potent antiinflammatory and analgesic activity. This paper describes the synthesis and the muscle relaxant, antiinflammatory, and analgesic structure-activity relationships of 17 and 67 of its analogues. Compound 17 has been taken into phase I clinical trials.


Assuntos
Acetamidas/síntese química , Analgésicos/síntese química , Anti-Inflamatórios não Esteroides/síntese química , Indanos/síntese química , Relaxantes Musculares Centrais/síntese química , Acetamidas/química , Acetamidas/farmacologia , Analgésicos/química , Analgésicos/farmacologia , Animais , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacologia , Hipnóticos e Sedativos/síntese química , Hipnóticos e Sedativos/química , Hipnóticos e Sedativos/farmacologia , Indanos/química , Indanos/farmacologia , Camundongos , Monoaminoxidase/metabolismo , Inibidores da Monoaminoxidase/síntese química , Inibidores da Monoaminoxidase/química , Inibidores da Monoaminoxidase/farmacologia , Relaxantes Musculares Centrais/química , Relaxantes Musculares Centrais/farmacologia , Ratos , Ratos Endogâmicos Lew , Ratos Wistar , Estereoisomerismo , Relação Estrutura-Atividade
11.
J Med Chem ; 46(3): 409-16, 2003 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-12540240

RESUMO

Extension of the structure-activity relationship studies that led to the discovery of the nonsedating potent muscle relaxant, antiinflammatory, and analgesic agent (E)-2-(4,6-difluoro-1-indanylidene)acetamide, 1, has given rise to (E)-2-(4-chloro-6-fluoro-1-indanylidene)-N-methylacetamide, 2. Compound 2 is a potent antiinflammatory and analgesic agent without centrally acting muscle relaxant activity.


Assuntos
Acetamidas/síntese química , Analgésicos/síntese química , Anti-Inflamatórios não Esteroides/síntese química , Indanos/síntese química , Acetamidas/química , Acetamidas/farmacologia , Analgésicos/química , Analgésicos/farmacologia , Animais , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacologia , Hipnóticos e Sedativos/síntese química , Hipnóticos e Sedativos/química , Hipnóticos e Sedativos/farmacologia , Indanos/química , Indanos/farmacologia , Camundongos , Relaxantes Musculares Centrais/síntese química , Relaxantes Musculares Centrais/química , Relaxantes Musculares Centrais/farmacologia , Ratos , Estereoisomerismo , Relação Estrutura-Atividade
12.
Nature ; 418(6901): 994-8, 2002 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-12198550

RESUMO

Nucleosomal DNA is arranged in a higher-order structure that presents a barrier to most cellular processes involving protein DNA interactions. The cellular machinery involved in sister chromatid cohesion, the cohesin complex, also requires access to the nucleosomal DNA to perform its function in chromosome segregation. The machineries that provide this accessibility are termed chromatin remodelling factors. Here, we report the isolation of a human ISWI (SNF2h)-containing chromatin remodelling complex that encompasses components of the cohesin and NuRD complexes. We show that the hRAD21 subunit of the cohesin complex directly interacts with the ATPase subunit SNF2h. Mapping of hRAD21, SNF2h and Mi2 binding sites by chromatin immunoprecipitation experiments reveals the specific association of these three proteins with human DNA elements containing Alu sequences. We find a correlation between modification of histone tails and association of the SNF2h/cohesin complex with chromatin. Moreover, we show that the association of the cohesin complex with chromatin can be regulated by the state of DNA methylation. Finally, we present evidence pointing to a role for the ATPase activity of SNF2h in the loading of hRAD21 on chromatin.


Assuntos
Adenosina Trifosfatases/metabolismo , Proteínas de Ciclo Celular/metabolismo , Cromatina/química , Cromatina/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Cromossomos Humanos/química , Cromossomos Humanos/metabolismo , Proteínas Nucleares/metabolismo , Fosfoproteínas/metabolismo , Elementos Alu/genética , Cromatina/genética , Cromossomos Humanos/genética , DNA/química , DNA/genética , DNA/metabolismo , Metilação de DNA , Proteínas de Ligação a DNA/metabolismo , Proteínas Fúngicas , Células HeLa , Humanos , Substâncias Macromoleculares , Testes de Precipitina , Ligação Proteica , Subunidades Proteicas , Retroelementos/genética
13.
Doc Ophthalmol ; 104(2): 195-212, 2002 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11999627

RESUMO

PURPOSE: To compare the visual electrophysiology and visual fields of patients taking vigabatrin to those of a control group of epileptics on other anti-epileptic drugs (AEDs). METHODS: Fourteen epileptics treated with vigabatrin and 10 control patients treated with other AEDs underwent ERG and EOG. Goldmann visual fields were performed and analysed using standard software to measure areas contained within I4e isopters. RESULTS: The cone and rod b-waves of the ERG, the oscillatory potential amplitudes and Arden indices were reduced in vigabatrin-treated subjects and the oscillatory potentials delayed. The Arden indices were reduced due to an increased dark trough. The areas contained within the I4e isopter of vigabatrin treated subjects were reduced compared to the control group and these areas correlated well with oscillatory potential amplitudes and b-wave amplitudes in the vigabatrin group only. CONCLUSIONS: The use of vigabatrin is associated with a reduction of the ERG cone b-wave amplitude and oscillatory potentials which correlates with visual field loss. The Arden ratio is reduced in subjects taking vigabatrin but may recover after cessation. However, visual loss may persist in the presence of a recovered EOG. These findings suggest further effects of the drug than those mediated by GABA receptors, and support the contention that the cause of the field loss may be at least in part due to retinal effects. Possible mechanisms are discussed.


Assuntos
Anticonvulsivantes/efeitos adversos , Epilepsia/tratamento farmacológico , Epilepsia/fisiopatologia , Retina/efeitos dos fármacos , Retina/fisiopatologia , Vigabatrina/efeitos adversos , Campos Visuais/efeitos dos fármacos , Adulto , Anticonvulsivantes/uso terapêutico , Grupos Controle , Eletroculografia , Eletrorretinografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Células Fotorreceptoras Retinianas Cones/efeitos dos fármacos , Células Fotorreceptoras Retinianas Cones/fisiopatologia , Células Fotorreceptoras Retinianas Bastonetes/efeitos dos fármacos , Células Fotorreceptoras Retinianas Bastonetes/fisiopatologia , Vigabatrina/uso terapêutico
14.
Br J Ophthalmol ; 85(12): 1437-9, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11734516

RESUMO

AIMS: To evaluate the visual and anatomical outcome, as well as complications following surgery, for rhegmatogenous retinal detachment in children at a tertiary referral centre over a 5 year period. METHODS: A retrospective survey of all children (aged 0-16 years) who underwent primary retinal detachment surgery at Queen's Medical Centre between April 1994 and March 1999. RESULTS: 15 consecutive patients were identified with a mean follow up of 14.7 months (range 3-57) and a mean age of 12.4 years. Trauma was the cause in 40% (6/15). Complete retinal reattachment was achieved in 86.6% (13/15). Visual improvement occurred in 53.3% (8/15), worsening of vision occurred in 13.3% (2/15), with no change in the remaining 33.3% (5/15). Visual acuity was D 6/12 in 6.6% (1/15) preoperatively, and 26.6% (4/15) postoperatively. CONCLUSIONS: Retinal detachment in children is rare compared with adults. There are therefore limited data available for this group of patients. These data provide one unit's experience over a 5 year period, and may help provide a basis for information for patients and their parents when discussing the risks and potential benefits of surgery for retinal detachment in the paediatric population.


Assuntos
Descolamento Retiniano/cirurgia , Adolescente , Criança , Feminino , Seguimentos , Humanos , Masculino , Complicações Pós-Operatórias , Descolamento Retiniano/etiologia , Descolamento Retiniano/fisiopatologia , Estudos Retrospectivos , Resultado do Tratamento , Acuidade Visual , Ferimentos e Lesões/complicações
15.
Diabet Med ; 18(5): 388-94, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11472450

RESUMO

AIMS: To determine whether documented evidence of pre-existing maculopathy is present in Type 2 diabetic patients who require photocoagulation or vitrectomy for proliferative disease. This is a retrospective case notes review. METHODS: The study was performed at Queen's Medical Centre, UK. All patients listed in the laser register and operating theatre register over 5 years (March 1994 to March 1999) who had undergone pan retinal photocoagulation (PRP) for diabetic retinopathy, in one consultant firm, were studied. The medical records of patients who had undergone vitrectomy as their first treatment for proliferative diabetic retinopathy in a vitreo-retinal firm over the 5 years were examined. The proportion of patients with documented maculopathy before development of proliferative retinopathy was determined. RESULTS: All except 1/134 or 0.7% (95% confidence interval 0.1-4.5%) patients had documentation of macular signs in at least one eye prior to the patient's first session of PRP. Of the remaining 133, 104 (78%) had had focal or grid photocoagulation of the macula. The median time between the documentation of maculopathy before the first PRP treatment session was 16 months (interquartile range 7-36). Fourteen patients had vitrectomy and endolaser performed as the initial treatment for proliferative disease. All patients had documented maculopathy before the onset of proliferative disease. CONCLUSIONS: The results of this study suggest that in Type 2 diabetes, proliferative disease occurs relatively late compared with maculopathy. In such patients, maculopathy is almost invariably present when proliferative disease is detected.


Assuntos
Diabetes Mellitus Tipo 2/fisiopatologia , Retinopatia Diabética/fisiopatologia , Degeneração Macular/epidemiologia , Idade de Início , Idoso , Retinopatia Diabética/cirurgia , Inglaterra , Feminino , Humanos , Fotocoagulação , Degeneração Macular/fisiopatologia , Degeneração Macular/cirurgia , Masculino , Pessoa de Meia-Idade , Sistema de Registros , Vitrectomia
16.
J Med Chem ; 44(12): 1866-82, 2001 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-11384233

RESUMO

A series of 2-amino-5-arylthiobenzonitriles (1) was found to be active against HIV-1. Structural modifications led to the sulfoxides (2) and sulfones (3). The sulfoxides generally showed antiviral activity against HIV-1 similar to that of 1. The sulfones, however, were the most potent series of analogues, a number having activity against HIV-1 in the nanomolar range. Structural-activity relationship (SAR) studies suggested that a meta substituent, particularly a meta methyl substituent, invariably increased antiviral activities. However, optimal antiviral activities were manifested by compounds where both meta groups in the arylsulfonyl moiety were substituted and one of the substituents was a methyl group. Such a disubstitution led to compounds 3v, 3w, 3x, and 3y having IC50 values against HIV-1 in the low nanomolar range. When gauged for their broad-spectrum antiviral activity against key non-nucleoside reverse transcriptase inhibitor (NNRTI) related mutants, all the di-meta-substituted sulfones 3u-z and the 2-naphthyl analogue 3ee generally showed single-digit nanomolar activity against the V106A and P236L strains and submicromolar to low nanomolar activity against strains E138K, V108I, and Y188C. However, they showed a lack of activity against the K103N and Y181C mutant viruses. The elucidation of the X-ray crystal structure of the complex of 3v (739W94) in HIV-1 reverse transcriptase showed an overlap in the binding domain when compared with the complex of nevirapine in HIV-1 reverse transcriptase. The X-ray structure allowed for the rationalization of SAR data and potencies of the compounds against the mutants.


Assuntos
Fármacos Anti-HIV/síntese química , Transcriptase Reversa do HIV/antagonistas & inibidores , Nitrilas/síntese química , Sulfonas/síntese química , Fármacos Anti-HIV/química , Fármacos Anti-HIV/farmacologia , Sítios de Ligação , Linhagem Celular Transformada , Cristalografia por Raios X , Transcriptase Reversa do HIV/química , Vírus Linfotrópico T Tipo 1 Humano/genética , Humanos , Modelos Moleculares , Conformação Molecular , Estrutura Molecular , Nitrilas/química , Nitrilas/farmacologia , Conformação Proteica , Relação Estrutura-Atividade , Sulfonas/química , Sulfonas/farmacologia
17.
Biochemistry ; 40(7): 2096-103, 2001 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-11329278

RESUMO

The extensive C-terminal molecular heterogeneity of alpha- and beta-tubulin is a consequence of multiple isotypes, the products of distinct genes, that undergo several posttranslational modifications. These include polyglutamylation and polyglycylation of both subunits, reversible tyrosination and removal of the penultimate glutamate from alpha-tubulin, and phosphorylation of the beta III isotype. A mass spectrometry-based method has been developed for the analysis of the C-terminal diversity of tubulin from human cell lines. Total cell extracts are resolved by SDS--PAGE and transferred to nitrocellulose, and the region of the blot corresponding to tubulin (approximately 50 kDa) was excised and digested with CNBr to release the highly divergent C-terminal tubulin fragments. The masses of the human alpha- and beta-tubulin CNBr-derived C-terminal peptides are all in the 1500--4000 Da mass range and can be analyzed directly by MALDI-TOF mass spectrometry in the negative ion mode without significant interference from other released peptides. In this study, the tubulin isotype diversity in MDA-MB-231, a human breast carcinoma cell line, and A549, a human non-small lung cancer cell line, is reported. The major tubulin isotypes present in both cell lines are k-alpha 1 and beta 1. Importantly, we report a previously unknown alpha isotype present at significant levels in both cell lines. Moreover, the degree of posttranslational modifications to all isotypes was limited. Glu-tubulin, in which the C-terminal tyrosine of alpha-tubulin is removed, was not detected. In contrast to mammalian neuronal tubulin which exhibits extensive polyglutamylation, only low-level monoglutamylation of the k-alpha 1 and beta 1 isotypes was observed in these two human cell lines.


Assuntos
Neoplasias da Mama/metabolismo , Neoplasias Pulmonares/metabolismo , Tubulina (Proteína)/biossíntese , Tubulina (Proteína)/química , Sequência de Aminoácidos , Animais , Química Encefálica , Neoplasias da Mama/química , Bovinos , Brometo de Cianogênio , Ácido Glutâmico/metabolismo , Humanos , Neoplasias Pulmonares/química , Espectrometria de Massas , Dados de Sequência Molecular , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/classificação , Fragmentos de Peptídeos/isolamento & purificação , Filogenia , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/química , Isoformas de Proteínas/classificação , Isoformas de Proteínas/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Tubulina (Proteína)/classificação , Tubulina (Proteína)/isolamento & purificação , Células Tumorais Cultivadas
18.
Clin Neuropharmacol ; 24(2): 117-9, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11307050

RESUMO

Clozapine is known to be beneficial for the treatment of dopamine agonist-induced psychotic states in patients with Parkinson's disease (PD). Many reports have suggested that it may also be efficacious for the treatment of parkinsonian tremor. We describe a patient with schizophrenia in whom early-onset PD appeared after treatment with antipsychotic drugs. When the parkinsonian symptoms proved resistant to anticholinergic agents, we introduced a trial with up to 50 mg clozapine daily, which yielded a prompt and dramatic response. Thereafter, the parkinsonian symptoms reappeared each time the patient discontinued clozapine and rapidly disappeared on its repeat initiation. There was also a marked improvement in his psychotic and depressive symptoms. This report suggests that some patients with concomitant schizophrenia and PD-a difficult treatment challenge-may benefit from clozapine treatment alone for both disorders.


Assuntos
Antipsicóticos/administração & dosagem , Clozapina/administração & dosagem , Doença de Parkinson/tratamento farmacológico , Esquizofrenia , Adulto , Humanos , Masculino , Doença de Parkinson/diagnóstico , Esquizofrenia/tratamento farmacológico
19.
Br J Ophthalmol ; 85(4): 461-70, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11264138

RESUMO

AIM: To examine the contribution of infiltrating cells in the local production of cytokines within the vitreous of patients with proliferative vitreoretinopathy (PVR). METHODS: The presence of mRNA coding for IL-6, IL-8, IL-1beta, IL-1alpha, TNFalpha, IFNgamma, IL-12, and HPRT was investigated in 25 vitreous samples from patients with PVR, 11 vitreous samples from patients with retinal detachment (RD) not complicated by PVR, and 10 vitreous samples from patients with macular hole (MH). A quantitative reverse transcriptase polymerase chain reaction (RT-PCR) using an internal competitor was used to investigate these samples. From these samples, 15 PVR, 8 RD, and 8 MH were analysed for the protein levels of the same cytokines using enzyme linked immunosorbent assay (ELISA). Spearman correlation was used to test any association between mRNA and cytokine protein levels, as an indicator of the contribution these cells make to the intravitreal cytokine milieu. RESULTS: A strong correlation was found between mRNA and their respective cytokine levels (protein products) for IL-6, IL-8, IL-1beta, IL-1alpha, TNFalpha, IFNgamma (Spearman r = 0.83, 0.73, 0.67, 0.91, 0.73, and 0.73 respectively), but not for IL-12. The median levels of IL-6, IL-8, IL-1beta, and IFNgamma mRNA and their respective cytokines were significantly higher (p <0.05) in patients with PVR than in those with macular hole. There was no statistically significant difference in the median levels of IL-1alpha mRNA between PVR and MH but the cytokine IL-1alpha was detected at a significantly higher level in PVR compared with MH patients. Between PVR and RD patients, there was no statistically significant difference in mRNA levels for all the investigated cytokines (p >0.05) except for IL-6 where there was a statistical significance (p= 0.038). In contrast, the median levels of IL-6, IL-8, and IL-1beta cytokines were significantly higher (p <0.05) in patients with PVR than in those with RD, whereas for IL-1alpha and IFNgamma no significant statistical difference was detected between PVR and RD patients (p >0.05). When results of RD and MH patients were compared, a statistical difference was only detected in mRNA levels of INFgamma (p = 0.008). However, no difference was detected for INFgamma (protein product) or for any of the other cytokines between RD and MH patients. CONCLUSION: Levels of both protein and mRNA encoding IL-6, IL-8, IL-1beta, and IFNgamma is significantly increased in vitreous samples from patients with PVR. The strong correlation between ELISA detectable cytokines (protein products) and their respective mRNA levels suggest that intravitreal, invasive cells are the major source of these cytokines, with the exception of IL-12. Cells invading the vitreous do not appear to locally produce IL-12 mRNA. This would appear to implicate cells peripheral to the vitreal mass as the major source of this cytokine.


Assuntos
Citocinas/metabolismo , Vitreorretinopatia Proliferativa/imunologia , Corpo Vítreo/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Hipoxantina Fosforribosiltransferase/metabolismo , Interferon gama/metabolismo , Interleucina-1/metabolismo , Interleucina-12/metabolismo , Interleucina-6/metabolismo , Interleucina-8/metabolismo , Masculino , Pessoa de Meia-Idade , RNA Mensageiro , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Estatísticas não Paramétricas , Fator de Necrose Tumoral alfa/metabolismo , Vitreorretinopatia Proliferativa/patologia
20.
Hippocampus ; 11(6): 647-54, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11811658

RESUMO

A modulatory role for the hippocampal theta rhythm in synaptic plasticity is suggested by the observations that theta occurs during exploratory behaviors, spatial learning is impaired when the theta rhythm is disrupted, and excitation of hippocampal principal cells is phase-coupled to the theta wave. The theta phase affects the nature of the plasticity induced in urethane-anesthetized rats and in the carbachol-treated in vitro slice preparation, but these oscillations are phenomenologically different from natural theta, and the effects of theta phase on plasticity under natural conditions have not been reported. We therefore examined the effects of theta phase on the magnitude of long-term potentiation (LTP) in awake rats running on a linear track for a food reward. Twelve adult and 10 aged F344 male rats were implanted with a stimulating electrode in the perforant path and a recording electrode in the hilus of the fascia dentata. Stimuli were delivered at the peak or trough of the hilar theta rhythm. In both adult and aged, memory-impaired rats, LTP lasting at least 48 h was induced when stimuli were delivered at the positive theta peak, whereas LTP was not induced when stimuli were delivered at the negative troughs. Consistent with the finding that the threshold for LTP induction is increased at this synapse in old rats, the magnitude of LTP induced at the peak of theta rhythm was significantly lower in old animals. These data confirm that LTP can be modulated by locomotion-induced theta, and that this modulation is at least qualitatively preserved across age.


Assuntos
Envelhecimento/fisiologia , Giro Denteado/fisiologia , Hipocampo/fisiologia , Plasticidade Neuronal/fisiologia , Sinapses/fisiologia , Ritmo Teta , Animais , Comportamento Animal/fisiologia , Sinais (Psicologia) , Discriminação Psicológica , Técnicas In Vitro , Potenciação de Longa Duração/fisiologia , Masculino , Aprendizagem em Labirinto/fisiologia , Ratos , Ratos Sprague-Dawley , Natação
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