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1.
JACS Au ; 4(5): 2029-2040, 2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38818062

RESUMO

Supporting students with upholding the principles of academic integrity is an important aspect of teaching. Academic integrity is especially important in chemistry laboratory classrooms, where students gain hands-on experience related to research and scientific practices. Prior literature on academic integrity largely focuses on catching and preventing cheating, describing various factors commonly associated with cheating behaviors. This body of literature assumes that students neutralize their feelings about cheating to engage in unethical behavior. In contrast, for this study, we began with the assumption that students intend to act ethically; to this end, we sought to investigate students' perceptions, evaluations, and motivations related to cheating and academic integrity. We interviewed 24 students enrolled in general chemistry laboratories and asked questions related to cheating and academic integrity. Additionally, to address concerns about social desirability bias affecting students' responses, we asked students questions involving hypothetical scenarios related to academic integrity that were contextualized within the chemistry laboratory classroom. In our analysis, we found that students held common views about cheating and academic integrity in general but diverged in their responses to the hypothetical scenarios. Our findings suggest the importance of providing clearer, more direct instruction regarding what counts as cheating and how to engage in academically honest behavior within the chemistry laboratory classroom.

2.
Clin Exp Immunol ; 204(3): 352-360, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33755987

RESUMO

Common variable immunodeficiency disorders (CVID) are multi-system disorders where target organ damage is mediated by infective, autoimmune and inflammatory processes. Bronchiectasis is probably the most common disabling complication of CVID. The risk factors for bronchiectasis in CVID patients are incompletely understood. The New Zealand CVID study (NZCS) is a nationwide longitudinal observational study of adults, which commenced in 2006. In this analysis, the prevalence and risk factors for bronchiectasis were examined in the NZCS. After informed consent, clinical and demographic data were obtained with an interviewer-assisted questionnaire. Linked electronic clinical records and laboratory results were also reviewed. Statistical methods were applied to determine if variables such as early-onset disease, delay in diagnosis and increased numbers of infections were associated with greater risk of bronchiectasis. One hundred and seven adult patients with a diagnosis of CVID are currently enrolled in the NZCS, comprising approximately 70% of patients known to have CVID in New Zealand. Fifty patients (46·7%) had radiologically proven bronchiectasis. This study has shown that patients with compared to those without bronchiectasis have an increased mortality at a younger age. CVID patients with bronchiectasis had a greater number of severe infections consequent to early-onset disease and delayed diagnosis. Indigenous Maori have a high prevalence of CVID and a much greater burden of bronchiectasis compared to New Zealand Europeans. Diagnostic latency has not improved during the study period. Exposure to large numbers of infections because of early-onset disease and delayed diagnosis was associated with an increased risk of bronchiectasis. Earlier diagnosis and treatment of CVID may reduce the risk of bronchiectasis and premature death in some patients.


Assuntos
Bronquiectasia/imunologia , Imunodeficiência de Variável Comum/imunologia , Estudos de Coortes , Diagnóstico Tardio , Feminino , Humanos , Imunoglobulinas Intravenosas/imunologia , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Nova Zelândia , Prevalência
4.
Plast Reconstr Surg ; 104(6): 1828-30, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10541188

RESUMO

Elicitation of the oculocardiac reflex is a well-documented phenomenon encountered during ophthalmologic surgical procedures. Familiarity with and prompt recognition of this entity has significantly reduced the morbidity associated with it; however, potentially lethal arrhythmias and cardiac arrest still occur. We report elicitation of the reflex during manipulation of the supraorbital nerve during endoscopic forehead lift surgery. To our knowledge this is the first case of elicitation of the oculocardiac reflex reported during endoscopic forehead lift surgery.


Assuntos
Endoscopia , Testa/cirurgia , Complicações Intraoperatórias/etiologia , Reflexo Oculocardíaco/fisiologia , Ritidoplastia , Bradicardia/fisiopatologia , Feminino , Humanos , Complicações Intraoperatórias/fisiopatologia , Pessoa de Meia-Idade
5.
Am J Med Genet ; 85(5): 502-10, 1999 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-10405451

RESUMO

We describe the main clinical and biochemical findings in 15 patients with peroxisomal disorders, together with the results of 11 prenatal investigations for Zellweger syndrome. The initial laboratory diagnosis depended in most cases on demonstration of elevated very long chain fatty acids in plasma, but follow-up studies using cultured fibroblasts were essential for complete classification. The patient group comprises nine cases of Zellweger syndrome, one of neonatal adrenoleucodystrophy, two of infantile Refsum disease, one of bifunctional protein deficiency, and two of rhizomelic chondrodysplasia punctata. The study illustrates the clinical and biochemical variability of this group of patients and the detailed studies that are required for classification.


Assuntos
Transtornos Peroxissômicos/diagnóstico , Transtornos Peroxissômicos/genética , Diagnóstico Pré-Natal , Células Cultivadas , Criança , Pré-Escolar , Feminino , Fibroblastos/patologia , Humanos , Recém-Nascido , Masculino , Transtornos Peroxissômicos/embriologia , Fenótipo , Ácido Fitânico/sangue , Gravidez , Ultrassonografia Pré-Natal , Síndrome de Zellweger/diagnóstico , Síndrome de Zellweger/embriologia , Síndrome de Zellweger/genética
6.
Clin Exp Immunol ; 114(3): 455-61, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9844057

RESUMO

Anti-liver cytosol 1 autoantibody (LC1) characterizes a severe form of autoimmune hepatitis (AIH), staining the cytoplasm of periportal hepatocytes and targeting an unidentified 60-kD liver cytosolic antigen. To identify its target, we used high-titre anti-LCI+ sera from two patients with AIH to screen 18 cytoplasm enzymes with periportal location by double immunodiffusion (DDI). Both sera gave a broad precipitin line against human liver cytosol, suggesting that they may recognize two distinct antigens, a possibility confirmed by the appearance of two precipitin lines when DDI conditions were optimized (0.8% agarose and 3% polyethylene glycol (PEG)). Experiments by DDI and Western blot (WB) identified a liver cytosolic autoantigen of 50 kD, different from LC1, giving a line of identity with argininosuccinate lyase (ASL). Reactivity to ASL was then investigated by DDI and WB in 57 patients with AIH, 17 with primary biliary cirrhosis (PBC), 15 with chronic hepatitis B virus (HBV) infection, 13 with alphal-antitrypsin deficiency, 17 with Wilson's disease, 18 with extrahepatic autoimmune disorders, and in 48 healthy controls. Anti-ASL was found in 16% of AIH and 23% of PBC patients by DDI and in 14% of AIH, 23% of PBC and 20% of HBV patients by WB. No argininosuccinate was present in the urine of four anti-ASL+ patients tested, excluding an inhibition of enzymatic activity by anti-ASL. The addition of anti-ASL+ serum to human fibroblast cultures induced a significant increase in ASL activity. ASL is a new autoantigen in liver disease and its clinical relevance warrants further investigation.


Assuntos
Argininossuccinato Liase/imunologia , Autoanticorpos/imunologia , Autoantígenos/imunologia , Hepatite Autoimune/imunologia , Autoantígenos/classificação , Western Blotting , Criança , Pré-Escolar , Feminino , Humanos , Imunodifusão
8.
Int J Cancer ; 76(2): 223-7, 1998 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-9537584

RESUMO

Previous results have shown that the insulin-like growth factor type I receptor (IGF-I-R) plays a critical role in the control of rhabdomyosarcoma (RMS) growth. The purpose of this study was to investigate whether a mutated IGF-I-R, when expressed in RMS cells, may interfere with the function of the endogenous wild-type IGF-I-R. We also examined whether the expression of a mutated IGF-I-R may induce phenotypic changes in RMS cells. We used here the mutated IGF-I-R with a lysine to arginine residue 1003 substitution, called IGF-I-KR, which carries a mutation in the ATP-binding domain of the intracellular beta subunit, while the extracellular, ligand binding alpha subunit remains unchanged. We observed that the expression of this mutated IGF-I-KR markedly decreased the response of RMS cells to stimulation with IGF-I. While stimulation with IGF-I increases the autophosphorylation of IGF-I-R in the parent cells, stimulation with IGF-I failed to produce a comparable increase in autophosphorylation in the cells expressing the mutated IGF-I-KR. We also observed a decreased plating efficiency of cells expressing the mutated IGF-I-KR. Consistently, a decrease of RMS growth in vivo was observed in an animal model. Our data suggest that the IGF/IGF-I-R signaling pathway may be inhibited by expressing a mutated IGF-I-KR and that such a mutant gene could be utilized in developing novel therapeutic strategies to suppress RMS growth. 1998.


Assuntos
Receptor IGF Tipo 1/fisiologia , Rabdomiossarcoma/patologia , Rabdomiossarcoma/ultraestrutura , Divisão Celular/fisiologia , Humanos , Fator de Crescimento Insulin-Like I/farmacologia , Substâncias Macromoleculares , Mutação , Células-Tronco Neoplásicas , Fosforilação , Receptor IGF Tipo 1/genética , Receptor IGF Tipo 1/metabolismo , Rabdomiossarcoma/metabolismo , Estimulação Química , Transfecção , Células Tumorais Cultivadas
9.
Biotechnol Bioeng ; 57(2): 211-5, 1998 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-10099195

RESUMO

The induction of catalytic activity in proteins by lyophilization in the presence of a transition state analogue (biomolecular imprinting) has been attempted. It was shown that proteins which were freeze-dried with n-isopropyl-4-nitrobenzyl-amine (a transition state analogue for the reaction of dehydrofluorination of 4-fluoro-4-[p-nitrophenyl] butan-2-one) displayed higher beta-elimination activity as compared to their-non-imprinted counterparts. It was also found that native bovine serum albumin has a high dehydrofluorination activity towards the above substrate with kinetic parameters rather similar to those of a catalytic antibody prepared by Shokat et al. (1989). A comparison of the kinetic parameters determined in this study with those obtained for analogous catalytic antibodies and imprinted polymers was made.


Assuntos
Proteínas/isolamento & purificação , Proteínas/metabolismo , Alquilação , Animais , Sítios de Ligação , Biotecnologia , Catálise , Bovinos , Liofilização , Técnicas In Vitro , Oxirredução , Conformação Proteica , Proteínas/química , Soroalbumina Bovina/química , Soroalbumina Bovina/isolamento & purificação , Soroalbumina Bovina/metabolismo
11.
Clin Genet ; 44(6): 313-9, 1993 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8131303

RESUMO

Four Baluch siblings with mucolipidosis type III (pseudo-Hurler polydystrophy) are described. The patients had features commonly found in mucolipidosis III, including claw hands, joint stiffness, aortic valve involvement and radiological dysostosis multiplex. However, intelligence was normal, there were no eye abnormalities on slit-lamp examination and skin elasticity was normal. Many lysosomal enzymes were elevated in serum and diminished in cultured fibroblasts, although the findings for beta-galactosidase were atypical. Assays for the two enzymes involved in formation of the phosphomannose recognition marker revealed normal activity of the phosphotransferase with alpha-methylmannoside as an acceptor, and normal activity of the phosphodiester glycosidase. Metabolic labelling of fibroblasts with 32P followed by immunoprecipitation of cathepsin D, electrophoresis and fluorography showed that this enzyme was not labelled in the patients' cells, although some label was detected in the secreted precursor polypeptide. The data are consistent with the assumption that activity of the phosphotransferase is low towards lysosomal enzymes as substrates, and that the patients belong to complementation group C.


Assuntos
Lisossomos/enzimologia , Mucolipidoses/enzimologia , Mucolipidoses/genética , Arilsulfatases/metabolismo , Catepsina D/metabolismo , Criança , Saúde da Família , Feminino , Fibroblastos/enzimologia , Glicosídeo Hidrolases/metabolismo , Humanos , Masculino , Mucolipidoses/etnologia , Mucolipidoses/patologia , Fosfotransferases/metabolismo , Polissacarídeos/urina , Testes de Precipitina , Emirados Árabes Unidos
12.
Cancer Immunol Immunother ; 34(6): 361-9, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1532922

RESUMO

The three forms of Fc gamma receptor carried by monocytes (Fc gamma RI, II) and natural killer (NK) cells (Fc gamma RIII) are all capable of mediating cell lysis. Here we compare the use of F(ab'gamma)2 bispecific antibodies, specifically targetting individual Fc gamma R, and chimeric IgG mouse/human antibodies which are capable of targetting all Fc gamma R, for their ability to mediate target cell destruction. The derivatives are prepared by linking hinge sulphydryl residues via tandem thioether bonds, using a bismaleimide crosslinker: Fab' from an anti-Fc gamma R mAb linked to Fab' from a common anti-target mAb (BsAb), or Fab' from the common anti-target mouse antibody linked to human Fc gamma (FabFc or bisFabFc). All the derivatives targetting chick red blood cells gave efficient lysis, although different effector cell donors yielded differences in both the lytic levels achieved and the comparative efficiencies of derivatives. In contrast, significant lysis of the guinea pig lymphoblastic leukaemia, L2C, regularly resulted only via the anti-Fc gamma RIII BsAb and the chimeric derivatives. These results suggest that the chimeric, Fc-containing derivatives mediate tumour cell lysis principally through Fc gamma RIII on NK cells. This is in contrast to the situation with the chick red blood cells where the chimeric derivatives appear capable of lysing erythrocytes by utilizing either monocytes or NK cells, because significant (approximately 50%) lysis occurred with effector cell populations magnetically depleted through either Fc gamma RII or Fc gamma RIII. A major difference between these two types of antibody derivative was their ability to function in the presence of high concentrations of normal human Fc gamma. The lysis mediated by BsAb reactive with Fc gamma RI or II was unaffected by the presence of human Fc gamma at 2.5 mg/ml (a concentration comparable with that yielded by IgG in plasma) whereas the BsAb recognizing Fc gamma RIII and all the Fc-containing derivatives were completely inhibited.


Assuntos
Anticorpos/análise , Citotoxicidade Celular Dependente de Anticorpos/imunologia , Antígenos de Diferenciação/imunologia , Fragmentos Fab das Imunoglobulinas/imunologia , Fragmentos Fc das Imunoglobulinas/imunologia , Imunoglobulina G/imunologia , Receptores Fc/imunologia , Animais , Anticorpos Monoclonais/imunologia , Especificidade de Anticorpos , Citotoxicidade Imunológica/imunologia , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos CBA , Monócitos/imunologia , Receptores de IgG
13.
Blood ; 77(5): 1071-9, 1991 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-1995092

RESUMO

Multiple myeloma is a disease in which conventional chemotherapy has only limited value, but which may be ideal for treatment with passive antibody against a suitable cell surface antigen on the neoplastic plasma cell. The CD38 antigen is known to be present on the majority of neoplastic plasma cells, and this was confirmed by detailed examination of bone marrow aspirates from three patients. Strong expression of CD38 was confined to cells which, by the criteria of light-scattering profiles and possession of cytoplasmic Ig, were plasma cells. The vast majority of neoplastic plasma cells appeared to be involved. Using a cell line as a model, it was found that the CD38 antigen acts as a target for a chimeric antibody prepared from the antibody OKT10. The chimeric antibody consists of the Fab portion of the mouse monoclonal antibody linked by a stable thioether bond to an Fc molecule derived from human IgG1, thereby forming mouse Fab-human Fc. In contrast to the parent antibody, the chimeric molecule mediates antibody-dependent cellular cytotoxicity (ADCC) very efficiently with human blood mononuclear effector cells, and is effective at low concentration. Also, even though the CD38 antigen is present on natural killer cells, there appears to be little deleterious action of the antibody on effector cell function. The antibody also failed to affect the growth of progenitor cells of the granulocyte/macrophage or erythroid lineages present in normal bone marrows, despite the suspicion that these cells express the antigen. Other advantages of the CD38 molecule are that it is not found in the serum of patients with myeloma, and it does not appear to modulate in vitro. Fourteen patients with florid myeloma and on various chemotherapeutic regimes had an undiminished capacity to mediate ADCC with the chimeric antibody, when compared with normal individuals. The maintenance of ADCC activity, coupled with the known suppression of the antibody response in these patients, augers well for treatment with chimeric antibody.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Antígenos CD/imunologia , Antígenos de Diferenciação/imunologia , Mieloma Múltiplo/terapia , ADP-Ribosil Ciclase , ADP-Ribosil Ciclase 1 , Idoso , Anticorpos Monoclonais/química , Citotoxicidade Celular Dependente de Anticorpos , Medula Óssea/imunologia , Endocitose , Células-Tronco Hematopoéticas/imunologia , Humanos , Imunoterapia , Isoanticorpos/química , Isoanticorpos/uso terapêutico , Glicoproteínas de Membrana , Pessoa de Meia-Idade , Plasmócitos/imunologia
14.
Am J Med Genet ; 37(4): 534-8, 1990 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-2260603

RESUMO

Lysosomal storage diseases (LSD) are a group of more than 40 disorders, many of them with overlapping phenotype, in which clinical diagnosis is often difficult. Definitive diagnosis is based on enzyme assays, a large number of such assays usually being necessary during the investigation of each patient. In addition, there will frequently be a need for tissue culture in order to provide enough material for analysis. Taking into account these difficulties, we designed a flowchart for the detection of LSD that is based on 2 sets of tests requiring only random urine and heparinized blood. Here we describe this routine and report the results of its application to 105 Brazilian patients in whom a LSD was suspected. We think that the application of this rationale represents a saving of work and costs, and should be of special interest to genetic centers in developing countries.


Assuntos
Lisossomos/enzimologia , Erros Inatos do Metabolismo/diagnóstico , Brasil , Ensaios Enzimáticos Clínicos , Protocolos Clínicos , Testes Diagnósticos de Rotina/métodos , Humanos , Erros Inatos do Metabolismo/sangue , Erros Inatos do Metabolismo/urina , Fatores de Risco , Crânio/anormalidades
15.
J Med Genet ; 27(8): 499-504, 1990 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-2120445

RESUMO

Very low serum levels of high density lipoprotein cholesterol ranging from 8.6 to 13.9 mg/dl were detected in four out of 12 sibs of a Brazilian kindred with the non-neuropathic form of Niemann-Pick disease. Hepatosplenomegaly, interstitial infiltration of the lungs, absence of neurological signs, sea-blue histiocytes in the bone marrow and liver, and high values for serum acid phosphatase (18 to 32 U/l) were common to all affected children. Leucocyte acid sphingomyelinase activity ranged from 3.6 to 6.5% of mean control values, and fibroblast activity from 9 to 13% of mean controls. The parents had low-normal levels. The relationship between these findings is unclear and deserves further investigation.


Assuntos
HDL-Colesterol/sangue , Doenças de Niemann-Pick/metabolismo , Síndrome do Histiócito Azul-Marinho/metabolismo , Acetilesterase/análise , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Fibroblastos/enzimologia , Humanos , Leucócitos/enzimologia , Masculino , Pessoa de Meia-Idade , Doenças de Niemann-Pick/complicações , Síndrome do Histiócito Azul-Marinho/complicações , Esfingomielina Fosfodiesterase/deficiência , beta-Galactosidase/análise , beta-Glucosidase/análise
16.
Anticancer Drug Des ; 3(4): 219-30, 1989 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2930624

RESUMO

A new chimeric antibody for therapeutic use in human cancer is described. First the derivative FabFc was prepared by linking Fab' gamma from monoclonal antibody to Fc gamma from human normal IgG1. The bismaleimide linking agent forms a thioether bond with an SH group released by reduction of SS bonds in the hinge of each constituent. It follows that one of the original two SS bonds in the Fc hinge still has both its S atoms free, and this bond is reformed by thiol-disulphide interchange. The lone free SH in the Fc hinge can now be used to join two FabFc molecules through a similar bismaleimide linker to yield bisFabFc. As regards antibody activity against target cells, bisFabFc can be univalent, bivalent, or bispecific. Its juxtaposed dual Fc regions are designed to promote cooperative binding of effectors, and bisFabFc is indeed notably more powerful than its parent FabFc molecules in promoting complement lysis and antibody-dependent cellular cytotoxicity. However it is not possible at present to distinguish the separate contributions of Fc architecture, antibody affinity and other factors towards this improvement. In the present state of development a variety of FabFc against a given neoplasm may be prepared in high yield from mouse IgG1 and IgG2a antibodies, and when convenient dimerized to bisFabFc in any combination of specificities.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Fragmentos Fab das Imunoglobulinas , Fragmentos Fc das Imunoglobulinas , Imunoglobulina G , Animais , Especificidade de Anticorpos , Citotoxicidade Celular Dependente de Anticorpos , Reagentes de Ligações Cruzadas/farmacologia , Desenho de Fármacos , Humanos , Fragmentos Fab das Imunoglobulinas/análise , Fragmentos Fab das Imunoglobulinas/imunologia , Fragmentos Fab das Imunoglobulinas/isolamento & purificação , Fragmentos Fc das Imunoglobulinas/análise , Fragmentos Fc das Imunoglobulinas/imunologia , Fragmentos Fc das Imunoglobulinas/isolamento & purificação , Imunoglobulina G/imunologia , Imunoglobulina G/isolamento & purificação , Idiótipos de Imunoglobulinas/imunologia , Imunoterapia , Camundongos
17.
Artigo em Inglês | MEDLINE | ID: mdl-2570671

RESUMO

1. A morphological and electrophysiological map of the identifiable neurones and neuronal clusters of the paired pedal ganglia has been prepared. 2. Neuronal morphology was investigated using the fluorescent dye, Lucifer Yellow CH, whilst electrophysiological properties were studied using conventional intracellular recording techniques and the phase plane technique. 3. The paired pedal ganglia are largely symmetrical and giant neurones usually have contralateral homologues. 4. Neuronal clusters are also paired, but minor asymmetries, both of identifiable neurones and neuronal clusters have been found to exist. 5. These asymmetries are thought to be related to asymmetries of body form. 6. Most of the individually identifiable neurones possess obligatory axon branches which are invariant from one preparation to the next, but variant branches also occur. 7. Within the neuronal clusters, morphology appears to be more variable. 8. Individually identifiable neurones and neuronal clusters were characterized electrophysiologically according to the criteria of action potential shape, spontaneous activity pattern, electrical coupling and common synaptic inputs. 9. Homologous pairs of neurones usually have similar electrophysiological properties, as do those within clusters. 10. A number of wide-acting synaptic inputs have been identified on neurones of the pedal, buccal, visceral and parietal ganglia.


Assuntos
Gânglios/anatomia & histologia , Lymnaea/fisiologia , Potenciais de Ação , Animais , Gânglios/fisiologia , Lymnaea/anatomia & histologia , Neurônios/citologia , Neurônios/fisiologia , Sinapses/fisiologia
18.
Ann Ophthalmol ; 20(7): 251-5, 1988 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-3178078

RESUMO

Papillomas of the lacrimal canaliculus are very rare tumors and, when encountered in clinical practice, usually present with unilateral epiphora due to obstruction of the lacrimal drainage system. Surgical excision is usually curative although, on occasion, they may recur. The following case report concerns a patient with autosomal-dominant ichthyosis vulgaris and conjunctival and canalicular papillomas.


Assuntos
Neoplasias da Túnica Conjuntiva/complicações , Ictiose/complicações , Doenças do Aparelho Lacrimal/complicações , Papiloma/complicações , Adulto , Neoplasias da Túnica Conjuntiva/patologia , Neoplasias da Túnica Conjuntiva/cirurgia , Feminino , Humanos , Doenças do Aparelho Lacrimal/patologia , Doenças do Aparelho Lacrimal/cirurgia , Papiloma/patologia , Papiloma/cirurgia
19.
J Immunol Methods ; 108(1-2): 171-8, 1988 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-2965188

RESUMO

Functional rat/rat T cell hybrids were isolated for the first time by the fusion of spleen cells from rats tolerized to the hapten TNP to a HAT-sensitive rat thymoma (C58(NT)D). 11 fusions using different protocols were attempted to assess the optimal conditions for high hybridization frequency of the desired specificity. Interestingly, the cell density requirement of the non-transformed fusion partner took precedence over that of the C58 cell line, i.e., rat cells needed to be at high density after fusion, but others have reported that mouse cells prefer a much lower density even when the same line (C58) is used. Six fusions yielded hybridomas with between 3% and 70% of wells containing hybrids after three weeks of culture, depending on the protocol used. Phenotypically, all of the hybrids and clones tested expressed the W3/25 (rat CD4) antigen, but no OX-8 (rat CD8) or immunoglobulin molecules. A minority of hybrids were found to secrete factors able to suppress (a) proliferation, (b) antibody production, and (c) cells bearing IL-2 receptors, but none appeared to suppress the production of IL-2 itself. In contrast to non-transformed rat T cell lines, the T hybrids isolated were easy to grow to high densities, clone and freeze without the need to add exogenous antigen or lymphokines to the cultures at any stage.


Assuntos
Fusão Celular , Separação Celular/métodos , Células Híbridas , Técnicas Imunológicas , Linfócitos T Reguladores , Animais , Linhagem Celular , Células Clonais/imunologia , Células Clonais/metabolismo , Células Híbridas/classificação , Células Híbridas/imunologia , Células Híbridas/metabolismo , Cariotipagem , Masculino , Fenótipo , Ratos , Ratos Endogâmicos WF , Baço/citologia , Fatores Supressores Imunológicos/biossíntese , Linfócitos T Reguladores/classificação , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Timoma
20.
J Opt Soc Am A ; 3(8): 1182-8, 1986 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-3746506

RESUMO

Three subjects viewed, foveally and monocularly, a monochromatic test field of 0.6-deg diameter that was surrounded by a white annulus of 0.6-deg inner diameter and 4.5-deg outer diameter. The wavelength of the central test field was varied in steps of 10 nm from 440 to 640 nm, and its luminance was set to 100 Td. Center and surround were flashed together for 2 sec every 4 sec. The subjects adjusted the luminance of the surround so that the central field was perceived as having equal amounts of whiteness and blackness. The luminance of the surround required for this balance point varied with the wavelength of the test field in a manner that closely resembled a heterochromatic brightness matching function obtained under similar conditions. Control experiments ruled out the possibility that the subjects were making brightness matches between center and surround fields. Additional evidence was provided suggesting that the spectral responsivity of the putative white-black channel is best represented by a photopic spectral sensitivity curve based on equal brightness.


Assuntos
Percepção de Cores , Percepção Visual , Humanos , Luz , Estimulação Luminosa , Fotografação
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