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1.
J Intellect Disabil Res ; 67(6): 531-546, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36919000

RESUMO

BACKGROUND: Telehealth (i.e. the use of technology across distance) is widespread in many fields. Although its use for behavioural support for people with intellectual or developmental disabilities (IDD) is emerging, there are no known studies examining stakeholder perceptions of this. METHODS: A four-round Delphi consultation was conducted with 11 professionals and six family carers of children with IDD to generate consensus on what would influence participants' use of telehealth for behavioural support. Data were collected prior to the coronavirus pandemic. RESULTS: Thirty-six items reached consensus for professionals (26 advantages and 10 disadvantages/barriers) and 22 for family carers (8 advantages and 14 disadvantages/barriers). A range of solutions were also identified for the disadvantages/barriers. CONCLUSIONS: Participants were willing to use telehealth for behavioural support. However, disadvantages/barriers need to be addressed, and guidelines relating to the use of telehealth in this field are needed. We report a number of practice recommendations including combining telehealth with in-person supports where possible, incorporating video technologies, and considering client perspectives and confidence with telehealth methodologies.


Assuntos
Infecções por Coronavirus , Telemedicina , Criança , Humanos , Cuidadores
2.
Clin Exp Immunol ; 179(3): 500-8, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25293413

RESUMO

The role of complement in inflammatory bowel disease (IBD) has been studied primarily using acute models, and it is unclear how complement affects processes in more relevant chronic models of IBD in which modulation of adaptive immunity and development of fibrosis have pathogenic roles. Using mice deficient in C1q/mannose-binding lectin (MBL) or C3, we demonstrated an important role for these opsonins and/or the classical pathway C3 convertase in providing protection against mucosal injury and infection in a model of chronic dextran sulphate sodium (DSS)-induced colitis. In contrast, deficiency of the alternative pathway (fB(-/-) mice) had significantly less impact on injury profiles. Consequently, the effect of a targeted inhibitor of the alternative pathway was investigated in a therapeutic protocol. Following the establishment of colitis, mice were treated with CR2-fH during subsequent periods of DSS treatment and acute injury (modelling relapse). CR2-fH significantly reduced complement activation, inflammation and injury in the colon, and additionally reduced fibrosis. Alternative pathway inhibition also altered the immune response in the chronic state in terms of reducing numbers of B cells, macrophages and mature dendritic cells in the lamina propria. This study indicates an important role for the alternative pathway of complement in the pathogenesis and the shaping of an immune response in chronic DSS-induced colitis, and supports further investigation into the use of targeted alternative pathway inhibition for the treatment of IBD.


Assuntos
Colite/imunologia , Inativadores do Complemento/administração & dosagem , Via Alternativa do Complemento , Intestinos/efeitos dos fármacos , Proteínas Recombinantes de Fusão/administração & dosagem , Animais , Doença Crônica , Colite/induzido quimicamente , Colite/tratamento farmacológico , Complemento C3/genética , Fator H do Complemento/genética , Via Alternativa do Complemento/efeitos dos fármacos , Via Alternativa do Complemento/genética , Sulfato de Dextrana/administração & dosagem , Modelos Animais de Doenças , Feminino , Humanos , Imunidade nas Mucosas/efeitos dos fármacos , Imunidade nas Mucosas/genética , Intestinos/imunologia , Lectina de Ligação a Manose/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Terapia de Alvo Molecular , Receptores de Complemento 3d/genética , Proteínas Recombinantes de Fusão/genética
3.
Clin Exp Immunol ; 177(2): 500-8, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24730624

RESUMO

While there is evidence of a pathogenic role for complement in inflammatory bowel disease, there is also evidence for a protective role that relates to host defence and protection from endotoxaemia. There is thus concern regarding the use of systemic complement inhibition as a therapeutic strategy. Local delivery of a complement inhibitor to the colon by oral administration would ameliorate such concerns, but while formulations exist for oral delivery of low molecular weight drugs to the colon, they have not been used successfully for oral delivery of proteins. We describe a novel pellet formulation consisting of cross-linked dextran coated with an acrylic co-polymer that protects the complement inhibitor CR2-Crry from destruction in the gastrointestinal tract. CR2-Crry containing pellets administered by gavage, were characterized using a therapeutic protocol in a mouse model of dextran sulphate sodium (DSS)-induced colitis. Oral treatment of established colitis over a 5-day period significantly reduced mucosal inflammation and injury, with similar therapeutic benefit whether or not the proton pump inhibitor, omeprazole, was co-administered. Reduction in injury was associated with the targeting of CR2-Crry to the mucosal surface and reduced local complement activation. Treatment had no effect on systemic complement activity. This novel method for oral delivery of a targeted protein complement inhibitor will reduce systemic effects, thereby decreasing the risk of opportunistic infection, as well as lowering the required dose and treatment cost and improving patient compliance. Furthermore, the novel delivery system described here may provide similar benefits for administration of other protein-based drugs, such as anti-tumour necrosis factor-α antibodies.


Assuntos
Colite/imunologia , Colo/efeitos dos fármacos , Colo/imunologia , Proteínas Inativadoras do Complemento/administração & dosagem , Proteínas do Sistema Complemento/imunologia , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/imunologia , Administração Oral , Animais , Colite/induzido quimicamente , Colite/tratamento farmacológico , Colo/patologia , Ativação do Complemento/efeitos dos fármacos , Ativação do Complemento/imunologia , Sulfato de Dextrana/efeitos adversos , Modelos Animais de Doenças , Doenças Inflamatórias Intestinais/tratamento farmacológico , Doenças Inflamatórias Intestinais/imunologia , Mucosa Intestinal/patologia , Camundongos , Proteínas Recombinantes de Fusão/administração & dosagem
4.
Digit Health ; 10: 20552076241253093, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38726214

RESUMO

Objectives: Increased rates of mental health disorders and substance use among youth and young adults have increased globally, furthering the strain on an already burdened mental health system. Digital solutions have been proposed as a potential option for the provision of timely mental health services for youth, with little research exploring mental health professional views about using such innovative tools. In Alberta, Canada, we are evaluating the implementation and integration of a digital mental health (dMH) platform into existing service pathways. Within this paper we seek to explore mental health professionals' perceptions of the barriers and facilitators that may influence their utilization of digital MH-enabled measurement-based care (MBC) with the youth who access their services. Methods: A qualitative, descriptive methodology was used to inductively generate themes from focus groups conducted with mental health professionals from specialized mental health services and primary care networks in Alberta. Results: As mental health professionals considered the barriers and facilitators of using dMH with youth, they referenced individual and family barriers and facilitators to consider. Providers highlighted perceived barriers, including: first, cultural stigma, family apprehension about mental health care, and parental access to dMH and MBC as deterrents to providers adopting digital platforms in routine care; second, perceptions of increased responsibility and liability for youth in crisis; third, perception that some psychiatric and neurodevelopmental disorders in youth are not amenable to dMH; fourth, professionals contemplated youth readiness to engage with dMH-enabled MBC. Participants also highlighted pertinent facilitators to dMH use, noting: first, the suitability of dMH for youth with mild mental health concerns; second, youth motivated to report their changes in mental health symptoms; and lastly, youth proficiency and preference for dMH options. Conclusions: By identifying professionals' perceptions of barriers and facilitators for youth users, we may better understand how to address misconceptions about who is eligible and appropriate for dMH through training and education.

5.
J Exp Med ; 183(3): 1023-9, 1996 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-8642243

RESUMO

Natural immunity of humans to the cattle pathogen Trypanosoma brucei brucei has been attributed to the presence in normal human serum (NHS) of lytic factors for the parasites. We and others have shown that NHS contains two trypanolytic factors (herein termed TLF1 and TLF2) that can be separated by gel filtration. TLF1 copurifies with a subclass of high density lipoprotein (HDL), whereas TLF2 has a much higher molecular weight and does not appear to be a lipoprotein. We find that the trypanolytic activity of purified TLF1 is totally inhibited by exogenous haptoglobin (Hp) at concentrations (0.1 mg/ml) lower than those present in NHS (0.2-2 mg/ml). In contrast, exogenous Hp (up to 2.5 mg/ml) has no effect on the lytic activity of either NHS or isolated TLF2. Hp-depleted sera from patients with intravascular hemolysis is severalfold more trypanolytic than NHS. These sera contain only TLF1, and their lytic activity is totally abolished upon the addition of Hp (0.1 mg/ml). When NHS containing different Hp allotypes is fractionated by gel filtration, TLF1 activity is either revealed or remains masked, depending on whether it coelutes with Hp. Masked TLF1 activity in the column fractions is revealed if Hp is removed by density gradient ultracentrifugation. We conclude that endogenous Hp inhibits TLF1 activity, and that TLF2 is the main trypanolytic factor in NHS.


Assuntos
Fatores Biológicos/sangue , Lipoproteínas/sangue , Trypanosoma brucei brucei/imunologia , Tripanossomíase Africana/imunologia , Cloreto de Amônio/farmacologia , Animais , Fatores Biológicos/isolamento & purificação , Bovinos , Cromatografia em Gel , Ensaio de Imunoadsorção Enzimática , Haptoglobinas/farmacologia , Haptoglobinas/fisiologia , Humanos , Imunidade Inata , Lipoproteínas/isolamento & purificação , Lipoproteínas HDL/sangue , Tripanossomíase Africana/sangue
6.
J Exp Med ; 185(4): 745-53, 1997 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-9034152

RESUMO

CD59 is a widely distributed membrane-bound inhibitor of the cytolytic membrane attack complex (MAC) of complement. This small (77 amino acid) glycoprotein is a member of the Ly6 superfamily of proteins and is important in protecting host cells from the lytic and proinflammatory activity of the MAC. CD59 functions by binding to C8 and/or C9 in the nascent MAC and interfering with C9 membrane insertion and polymerization. We present data obtained from a combination of molecular modeling and mutagenesis techniques, which together indicate that the active site of CD59 is located in the vicinity of a hydrophobic groove on the face of the molecule opposite to a "hydrophobic strip" suggested earlier. In addition, removal of the single N-linked glycosylation site at Asn18 of CD59 resulted in an enhancement of complement inhibitory activity.


Assuntos
Antígenos CD59/metabolismo , Sequência de Aminoácidos , Animais , Antígenos de Superfície/genética , Antígenos de Superfície/metabolismo , Sítios de Ligação , Antígenos CD59/genética , Células CHO , Metabolismo dos Carboidratos , Cricetinae , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Homologia de Sequência de Aminoácidos
7.
J Exp Med ; 184(5): 1909-18, 1996 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-8920878

RESUMO

A prominent feature of the life cycle of intracellular parasites is the profound morphological changes they undergo during development in the vertebrate and invertebrate hosts. In eukaryotic cells, most cytoplasmic proteins are degraded in proteasomes. Here, we show that the transformation in axenic medium of trypomastigotes of Trypanosoma cruzi into amastigote-like organisms, and the intracellular development of the parasite from amastigotes into trypomastigotes, are prevented by lactacystin, or by a peptide aldehyde that inhibits proteasome function. Clasto-lactacystin, an inactive analogue of lactacystin, and cell-permeant peptide aldehyde inhibitors of T. cruzi cysteine proteinases have no effect. We have also identified the 20S proteasomes from T. cruzi as a target of lactacystin in vivo. Our results document the essential role of proteasomes in the stage-specific transformation of a protozoan.


Assuntos
Cisteína Endopeptidases/metabolismo , Complexos Multienzimáticos/metabolismo , Trypanosoma cruzi/crescimento & desenvolvimento , Acetilcisteína/análogos & derivados , Acetilcisteína/farmacologia , Animais , Diferenciação Celular/efeitos dos fármacos , Cisteína Endopeptidases/química , Cisteína Endopeptidases/isolamento & purificação , Cisteína Endopeptidases/ultraestrutura , Inibidores de Cisteína Proteinase/farmacologia , Relação Dose-Resposta a Droga , Complexos Multienzimáticos/química , Complexos Multienzimáticos/isolamento & purificação , Complexos Multienzimáticos/ultraestrutura , Complexo de Endopeptidases do Proteassoma , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/enzimologia
8.
J Exp Med ; 177(2): 465-74, 1993 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-8426115

RESUMO

Here we report the presence of a trans-sialidase on the surface of Trypanosoma brucei culture-derived procyclic trypomastigotes. The enzyme is not detected in lysates of bloodstream trypomastigotes enriched for either stumpy or slender forms. The trans-sialidase catalyzes the transfer of alpha(2-3)-linked sialic acid residues to lactose. beta-galactopyranosyl residues are at least 100 times better acceptors for sialic acid than alpha-galactopyranosyl residues. In the absence of efficient acceptors, the purified enzyme transfers sialic acid to water, i.e., it acts as a sialidase. Although the T. cruzi and T. brucei trans-sialidases have very similar donor and acceptor specificities, they are antigenically distinct. Sodium dodecyl sulfate-polyacramide gel electrophoresis under nonreducing conditions and silver staining of the purified trans-sialidase reveals a single band of 63 kD. When the surface membrane of live procyclic trypomastigotes is trans-sialylated, using radioactive sialyllactose as the donor substrate, it appears that the only sialylated surface molecule is procyclin. Pronase treatment of live parasites removes only part of the surface sialic acid, in agreement with recent data showing that the glycosylphosphatidylinositol anchor of procyclin is sialylated (Ferguson, M. A. J., M. Murray, H. Rutherford, and M. J. McConville. 1993. Biochem. J. In press).


Assuntos
Glicoproteínas de Membrana , Sialiltransferases/metabolismo , Trypanosoma brucei brucei/enzimologia , Glicoproteínas Variantes de Superfície de Trypanosoma/metabolismo , Animais , Neuraminidase/metabolismo , Proteínas de Protozoários/isolamento & purificação , Proteínas de Protozoários/metabolismo , Ácidos Siálicos/metabolismo , Sialoglicoproteínas/metabolismo , Sialiltransferases/isolamento & purificação , Trypanosoma brucei brucei/citologia , Trypanosoma cruzi/enzimologia
9.
Plant Biol (Stuttg) ; 22(2): 157-166, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31705712

RESUMO

Caladenia is a diverse Australian genus that is exceptional among orchids in having both species pollinated by food-seeking and sexually deceived insects. Here, we investigated the pollination of Caladenia nobilis, a species predicted to be food-deceptive due to its large, cream-coloured and apparently nectarless flowers. Pollinator observations were made using experimental clumps of flowers. Measurements of floral colour were undertaken with a spectrometer, nectar was tested using GC-MS, and reproductive success was quantified for 2 years. While C. nobilis attracted nine species of insect, only males of the thynnine wasp Rhagigaster discrepans exhibited the correct size and behaviour to remove and deposit pollen. Male R. discrepans attempted to feed from the surface of the labellum, often crawling to multiple flowers, but showed no evidence of sexual attraction. Most flowers produced little or no nectar, although some may provide enough sucrose to act as a meagre reward to pollinators. Floral colouration was similar to a related Caladenia species pollinated by sexual deception, although the sexually deceptive species had a dull-red labellum. Reproductive success was generally low and highly variable between sites and years. In addition to most visitors being of inappropriate size for pollinia removal, the lack of response to the orchid by several co-occurring species of thynnine wasp suggests filtering of potential pollinators at the attraction phase. Our discovery of a pollination strategy that may be intermediate between food deception and food reward raises the question, how many putatively rewardless orchids actually produce meagre amounts of nectar?


Assuntos
Orchidaceae , Polinização , Vespas , Animais , Austrália , Comportamento Animal , Tamanho Corporal , Flores , Masculino , Orchidaceae/fisiologia , Néctar de Plantas , Vespas/fisiologia
10.
J Cell Biol ; 109(6 Pt 1): 2801-8, 1989 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-2512300

RESUMO

The molecular details of the final step in the process of regulated exocytosis, the fusion of the membrane of the secretory granule with the plasma membrane, are at present obscure. As a first step in an investigation of this membrane fusion event, we have developed a cell-free assay for the interaction between pancreatic zymogen granules and plasma membranes. We show here that plasma membranes are able to trigger the release of the granule contents, and that this effect is specific to pancreatic membranes, involves membrane fusion, requires membrane proteins, and is stimulated by activators of G-proteins but not by Ca2+. The assay is simple, reliable, and rapid, and should permit the identification of proteins that are involved in the exocytotic fusion event.


Assuntos
Grânulos Citoplasmáticos/enzimologia , Precursores Enzimáticos/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Pâncreas/metabolismo , Animais , Cálcio/farmacologia , Membrana Celular/metabolismo , Membrana Celular/ultraestrutura , Grânulos Citoplasmáticos/ultraestrutura , Exocitose/efeitos dos fármacos , Guanosina 5'-O-(3-Tiotrifosfato) , Guanosina Trifosfato/análogos & derivados , Guanosina Trifosfato/farmacologia , Cinética , Fígado/metabolismo , Fígado/ultraestrutura , Masculino , Fusão de Membrana , Proteínas de Membrana/metabolismo , Pâncreas/ultraestrutura , Ratos , Ratos Endogâmicos , Tionucleotídeos/farmacologia , alfa-Amilases/metabolismo
11.
Oncogene ; 26(7): 970-81, 2007 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-16909112

RESUMO

Transforming growth factor-beta (TGFbeta)-activated signalling pathways can lead to apoptosis, growth arrest or promotion of malignant behaviour, dependent on cellular context. The molecular mechanisms involved in TGFbeta-induced apoptosis remain controversial; although changes in gene expression are thought to be pivotal to the process, several different candidate apoptotic initiators and mediators have been proposed. Smad4, a critical component of the TGFbeta-induced transcriptional machinery, is shown here to be essential for induction of apoptosis. Gene expression analysis identified the proapoptotic Bcl-2 family members, Bmf and Bim, as induced by TGFbeta, dependent on both Smad4 and p38 function and the generation of reactive oxygen species. TGFbeta-induced Bmf and Bim localize to cellular membranes implicated in apoptosis. Inhibition of the TGFbeta-induced expression of both these proteins together provides significant protection of cells from apoptosis. The TGFbeta-triggered cell death programme thus involves induction of multiple BH3-only proteins during the induction of apoptosis.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/biossíntese , Proteínas Reguladoras de Apoptose/biossíntese , Apoptose/fisiologia , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/biossíntese , Proteínas de Membrana/biossíntese , Proteínas Proto-Oncogênicas/biossíntese , Fator de Crescimento Transformador beta/fisiologia , Regulação para Cima/fisiologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Apoptose/genética , Proteínas Reguladoras de Apoptose/genética , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/genética , Proteína 11 Semelhante a Bcl-2 , Linhagem Celular , Linhagem Celular Tumoral , Proteínas de Membrana/genética , Camundongos , Proteínas Proto-Oncogênicas/genética , Ratos , Regulação para Cima/genética
12.
Clin Oncol (R Coll Radiol) ; 30(1): e9-e15, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29103853

RESUMO

AIMS: To assess adherence to adjuvant endocrine therapy by a real-world cohort of women in Christchurch and to determine any associated factors. MATERIALS AND METHODS: Records were retrieved of all women newly diagnosed with early breast cancer and registered on the Christchurch Breast Cancer Patient Register over 4 years from June 2009. Demographic and pathological factors, dates of starting and stopping endocrine therapies and reported side-effects were collected. The proportion remaining on endocrine therapy was analysed by Kaplan-Meier curve; Cox regression analysis was used to identify independent factors influencing adherence. RESULTS: Of 1213 women, 1018 (83.9%) had oestrogen receptor-positive tumours, of whom 674 (66.2%) started adjuvant endocrine therapy, including 62 (9.2%) neoadjuvantly. Uptake was 52.4% of those with T1 tumours, 89% with T2 tumours, 93% with T3/T4 tumours, 92.7% with node-positive tumours and 49.7% with node-negative tumours. The initial endocrine therapy was an aromatase inhibitor in 254 (38%) and tamoxifen for 412 (61%). At 1 year, 90% remained adherent, at 2 years 84%, at 3 years 81%, at 4 years 76%, at 4.5 years 71% and at 5 years 50%, with a median duration of 60 months (56-64 months, 95% confidence interval) and a median follow-up of 33 months. Overall, 135 (20%) women stopped treatment for adverse events or poor tolerability. A longer persistence with endocrine therapy was associated with node-positive tumours (hazard ratio 1.38, P = 0.003), but not first hormone used; aromatase inhibitor compared with tamoxifen, P = 0.76. CONCLUSION: Adjuvant endocrine therapy use fell to 50% by 5 years, limiting possible survival benefits, providing support for efforts to increase compliance.


Assuntos
Antineoplásicos Hormonais/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Quimioterapia Adjuvante/métodos , Terapia Combinada/métodos , Tamoxifeno/uso terapêutico , Idoso , Antineoplásicos Hormonais/farmacologia , Inibidores da Aromatase/uso terapêutico , Neoplasias da Mama/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Cooperação do Paciente , Tamoxifeno/farmacologia
13.
J Clin Invest ; 103(1): 55-61, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9884334

RESUMO

Complement is involved in the pathogenesis of many diseases, and there is great interest in developing inhibitors of complement for therapeutic application. CD59 is a natural membrane-bound inhibitor of the cytolytic complement membrane attack complex (MAC). In this study, the preparation and characterization of antibody-CD59 (IgG-CD59) chimeric fusion proteins are described. Constructs were composed of soluble CD59 fused to an antibody-combining site at the end of CH1, after the hinge (H), and after CH3 Ig regions. The antigen specificity of each construct was for the hapten 5-dimethylamino-naphthalene-1-sulfonyl (dansyl). Correct folding of each IgG-CD59 fusion partner was indicated by recognition with anti-CD59 antibodies specific for conformational determinants and by IgG-CD59 binding to dansyl. The IgG-CD59 fusion proteins all bound specifically to dansyl-labeled Chinese hamster ovary cells and provided targeted cells, but not untargeted cells, with effective protection from complement-mediated lysis. Data indicate that CD59 must be positioned in close proximity to the site of MAC formation for effective function, and that modes of membrane attachment other than glycophosphatidylinositol linkage can affect CD59 functional activity.


Assuntos
Antígenos CD59/imunologia , Complexo de Ataque à Membrana do Sistema Complemento/antagonistas & inibidores , Proteínas do Sistema Complemento/metabolismo , Imunoglobulina G/imunologia , Proteínas Recombinantes de Fusão/imunologia , Animais , Sítios de Ligação , Antígenos CD59/genética , Células CHO/imunologia , Cricetinae , Citotoxicidade Imunológica/imunologia , Compostos de Dansil/metabolismo , Citometria de Fluxo , Fragmentos de Imunoglobulinas/genética , Fragmentos de Imunoglobulinas/imunologia , Imunoglobulina G/genética , Ligação Proteica
14.
Curr Opin Immunol ; 5(1): 83-9, 1993 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8452679

RESUMO

The susceptibility of complement-deficient individuals to various severe infections, and studies of the effector mechanisms involved in the destruction of infectious agents, demonstrate the importance of complement in providing an effective host defense system. It is also becoming increasingly apparent that complement not only plays a role in 'natural' defenses against infection and in enhancing the antibody-mediated effector mechanisms, but also influences adaptive immune responses directly.


Assuntos
Proteínas do Sistema Complemento/fisiologia , Animais , Ativação do Complemento , Proteínas do Sistema Complemento/deficiência , Humanos , Imunidade Inata , Imunoterapia , Inflamação , Proteínas Opsonizantes/imunologia , Fagocitose
15.
Nat Biotechnol ; 14(6): 717-21, 1996 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9630977

RESUMO

The natural immunity of humans to the cattle pathogen Trypanosoma brucei brucei, but not to the morphologically indistinguishable human pathogens T. brucei gambiense and T. brucei rhodesiense, is due to the selective killing of the parasite by normal human serum. The factor in human serum that mediates lysis of T. brucei brucei has long been attributed to a minor subclass of high density lipoprotein (HDL). Evidence indicates that the trypanolytic activity of isolated human HDL is due to peroxidase activity of an associated haptoglobin-related protein-hemoglobin complex. However, recent data suggest that the trypanolytic activity of HDL may be completely inhibited in whole human serum, and that trypanolytic activity of norman human serum is due to a second, less well-defined factor of high molecular weight. Current research aimed at understanding the mechanisms of cytotoxicity and the affected metabolic pathways may open new approaches for the development of specific drugs and vaccines against trypanosomiasis.


Assuntos
Fenômenos Fisiológicos Sanguíneos , Imunidade Inata , Trypanosoma brucei brucei/imunologia , Animais , Humanos , Tripanossomíase/sangue
16.
J Dairy Sci ; 90(4): 1751-60, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17369215

RESUMO

The objectives of this study were to determine incidence of stillbirths and heifer-calf morbidity and mortality, and their association with dystocia on 3 Colorado dairies. A total of 7,380 calvings produced 7,788 calves on 3 Colorado dairy operations between October 1, 2001, and November 5, 2002. Dystocia score and calf status (alive vs. dead) were recorded at calving. Calves that were born alive, but died before 24 h of age, also were recorded as stillborn. Heifer calves were monitored for 120 d to evaluate morbidity and mortality. More than half (51.2%) of calves born to primiparous dams, compared with 29.4% of calves born to multiparous dams, required assistance during calving. A larger percentage of bull calves (40.0%) required assistance compared with heifer calves (33.0%). Proportion of stillborn calves was 8.2% overall, with bull calves, twin calves, calves born to primiparous dams, and those born to dams having dystocia having a larger stillbirth percentage compared with heifer calves, singletons, calves born to multiparous dams, and unassisted calvings, respectively. Multiple logistic regression models were constructed to evaluate stillbirths and heifer health while accounting for the clustering of calves within dairy. The models included dystocia score, parity, and season of calving as explanatory variables for heifer events and also calf gender, and single or twin birth for the stillbirth models. Heifer calves born to dams having severe dystocia had greater odds of stillbirth [odds ratio (OR) = 20.7] and treatment of respiratory disease (OR = 1.7), digestive disease (OR = 1.3), and overall heifer mortality (OR = 6.7). Calf gender and dam parity interacted with calving ease to affect stillbirths. For calves having severe dystocia, heifer calves and calves born to multiparous dams were at increased risk of stillbirth compared with bull calves and calves born to primiparous dams, respectively. Survival analysis demonstrated that severe dystocia was associated with stillbirths and deaths up to 30 d of age. Relatively simple interventions have the potential to significantly reduce the impact of dystocia on calf mortality and morbidity on dairy farms. Education of farm management and personnel in strategies to reduce dystocia and its effect on calf health should be a priority according to the results of this study.


Assuntos
Doenças dos Bovinos/epidemiologia , Distocia/veterinária , Nível de Saúde , Animais , Bovinos , Doenças dos Bovinos/mortalidade , Colorado/epidemiologia , Distocia/epidemiologia , Distocia/mortalidade , Feminino , Incidência , Modelos Logísticos , Paridade , Gravidez , Modelos de Riscos Proporcionais , Estações do Ano , Fatores Sexuais , Natimorto/epidemiologia , Natimorto/veterinária , Análise de Sobrevida
17.
Sci Rep ; 7(1): 1890, 2017 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-28507306

RESUMO

Fertilization of nitrogen (N)-limited ecosystems by anthropogenic atmospheric nitrogen deposition (Ndep) may promote CO2 removal from the atmosphere, thereby buffering human effects on global radiative forcing. We used the biogeochemical ecosystem model N14CP, which considers interactions among C (carbon), N and P (phosphorus), driven by a new reconstruction of historical Ndep, to assess the responses of soil organic carbon (SOC) stocks in British semi-natural landscapes to anthropogenic change. We calculate that increased net primary production due to Ndep has enhanced detrital inputs of C to soils, causing an average increase of 1.2 kgCm-2 (c. 10%) in soil SOC over the period 1750-2010. The simulation results are consistent with observed changes in topsoil SOC concentration in the late 20th Century, derived from sample-resample measurements at nearly 2000 field sites. More than half (57%) of the additional topsoil SOC is predicted to have a short turnover time (c. 20 years), and will therefore be sensitive to future changes in Ndep. The results are the first to validate model predictions of Ndep effects against observations of SOC at a regional field scale. They demonstrate the importance of long-term macronutrient interactions and the transitory nature of soil responses in the terrestrial C cycle.

18.
Cancer Gene Ther ; 13(12): 1045-51, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16763610

RESUMO

As of January 2005, there were 1020 gene therapy clinical trials ongoing worldwide with 675 or 66.2% devoted to cancer gene therapy. The majority are occurring in the US and Europe (http://www.wiley.co.uk/genetherapy/clinical/). At the present time, to our knowledge there are no trials that employ gene delivery of Fas Ligand (FasL). As an important note, and in contrast to somatic cell therapy trials, there are no reported deaths due to therapeutic vector administration in any cancer gene therapy trial. That said, from our studies and from the published literature, the issue of gene delivery remains the major obstacle to successfully employing gene therapy for cancer treatment. Numerous laboratories are studying this with many different approaches. My co-workers and I have focused on the delivery issue by using various approaches that address tumor targeting and transgene expression. In addition, we are focusing on enhancing tumor cell killing via the bystander effect and through use of small molecules to enhance bystander activity.


Assuntos
Ceramidas/metabolismo , Proteína Ligante Fas/uso terapêutico , Terapia Genética/métodos , Vetores Genéticos/uso terapêutico , Neoplasias de Cabeça e Pescoço/terapia , Neoplasias da Próstata/terapia , Adenoviridae/genética , Animais , Antineoplásicos/uso terapêutico , Efeito Espectador , Ensaios Clínicos como Assunto , Proteína Ligante Fas/genética , Proteína Ligante Fas/metabolismo , Neoplasias de Cabeça e Pescoço/genética , Humanos , Masculino , Neoplasias da Próstata/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/uso terapêutico , Transdução de Sinais , Transgenes
19.
Curr Opin Microbiol ; 4(4): 402-8, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11495802

RESUMO

A novel trypanosome lytic factor (TLF) has been characterized that protects humans from infection by Trypanosoma brucei brucei. The mechanism of trypanolysis is unknown; contrary to one hypothesis, TLF does not kill trypanosomes by generating oxygen radicals. However, these trypanosomes become human-infective when they express a serum-resistance-associated gene.


Assuntos
Lipoproteínas HDL/imunologia , Trypanosoma brucei brucei/imunologia , Tripanossomíase Africana/imunologia , Animais , Humanos , Imunidade Inata , Trypanosoma brucei brucei/patogenicidade
20.
Cancer Res ; 60(11): 3013-8, 2000 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-10850450

RESUMO

It has been hypothesized that complement inhibitors expressed on the surface of tumor cells prevent effective immune-mediated clearance. Whereas there are in vitro data to support this hypothesis, the species-selective activity of complement inhibitors has been a hindrance to investigating the role of membrane-bound complement inhibitors in rodent models of human cancer. The CD59-positive LAN-1 human neuroblastoma cell line was significantly more sensitive to lysis by rat complement than by human complement, illustrating the species selectivity of endogenously expressed complement inhibitors. Transfection of LAN-1 cells with rat CD59, an inhibitor of the terminal cytolytic membrane attack complex, effectively protected the cells from lysis by rat complement in vitro. When LAN-1 cells stably expressing rat CD59 were inoculated into immune-deficient rats, the onset of tumor growth and the rate of tumor growth were significantly enhanced compared with those of control-transfected LAN-1 cells. These data show directly that the expression of a complement inhibitor on a tumor cell promotes tumor growth. Flow cytometric analysis revealed that the endogenous expression of decay-accelerating factor (DAF), an inhibitor of complement activation, was up-regulated on the surface of cells after in vivo growth. Of further interest, higher levels of DAF were present on CD59-transfected cells than on control-transfected cells derived from tumors. Increased DAF expression correlated with decreased complement deposition on the tumor cell surface. These results show that expression of complement inhibitors on a tumor cell has functional consequences with regard to complement deposition in vivo and indicate that CD59 can indirectly effect complement activation and C3 deposition in vivo via a link between CD59 and DAF expression.


Assuntos
Antígenos CD55/metabolismo , Antígenos CD59/biossíntese , Neuroblastoma/metabolismo , Animais , Proteínas do Sistema Complemento/metabolismo , DNA Complementar/metabolismo , Citometria de Fluxo , Humanos , Imunidade Inata , Transplante de Neoplasias , Ratos , Ratos Nus , Fatores de Tempo , Transfecção , Células Tumorais Cultivadas , Regulação para Cima
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