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1.
Trop Med Int Health ; 29(7): 599-611, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38757387

RESUMO

OBJECTIVES: Although the link between poverty and tuberculosis (TB) is widely recognised, limited studies have investigated the association between neighbourhood factors and TB incidence. Since the factors influencing different episodes of TB might be different, this study focused on the first episode of TB disease (first-episode TB). METHODS: All first episodes in previously linked and geocoded TB notification data from 2007 to 2015 in Cape Town, South Africa, were aggregated at the neighbourhood level and merged with the 2011 census data. We conducted an ecological study to assess the association between neighbourhood incidence of first-episode TB and neighbourhood factors (total TB burden [all episodes] in the previous year, socioeconomic index, mean household size, mean age, and percentage males) using a negative binomial regression. We also examined the presence of hotspots in neighbourhood TB incidence with the Global Moran's I statistic and assessed spatial dependency in the association between neighbourhood factors and TB incidence using a spatial lag model. RESULTS: The study included 684 neighbourhoods with a median first-episode TB incidence rate of 114 (IQR: 0-345) per 100,000 people. We found lower neighbourhood socioeconomic index (SEI), higher neighbourhood total TB burden, lower neighbourhood mean household size, and lower neighbourhood mean age were associated with increased neighbourhood first-episode TB incidence. Our findings revealed a hotspot of first-episode TB incidence in Cape Town and evidence of spatial dependency in the association between neighbourhood factors and TB incidence. CONCLUSION: Neighbourhood TB burden and SEI were associated with first-episode TB incidence, and there was spatial dependency in this association. Our findings can inform targeted interventions to reduce TB in high-risk neighbourhoods, thereby reducing health disparities and promoting health equity.


Assuntos
Características de Residência , Fatores Socioeconômicos , Análise Espacial , Tuberculose , Humanos , África do Sul/epidemiologia , Incidência , Feminino , Masculino , Tuberculose/epidemiologia , Adulto , Pessoa de Meia-Idade , Adulto Jovem , Características da Vizinhança , Adolescente , Fatores de Risco , Criança , Pobreza , Pré-Escolar , Características da Família
2.
Environ Microbiome ; 18(1): 30, 2023 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-37024971

RESUMO

BACKGROUND: Bacterial communities are critical to ecosystem functioning and sensitive to their surrounding physiochemical environment. However, the impact of land use change on microbial communities remains understudied. We used 16S rRNA gene amplicon sequencing and shotgun metagenomics to assess soil microbial communities' taxonomic and functional responses to land use change. We compared data from long-term grassland, exotic forest and horticulture reference sites to data from sites that transitioned from (i) Grassland to exotic forest or horticulture and from (ii) Exotic forest to grassland. RESULTS: Community taxonomic and functional profiles of the transitional sites significantly differed from those within reference sites representing both their historic and current land uses (P < 0.001). The bacterial communities in sites that transitioned more recently were compositionally more similar to those representing their historic land uses. In contrast, the composition of communities from sites exposed to older conversion events had shifted towards the compositions at reference sites representing their current land use. CONCLUSIONS: Our study indicates that microbial communities respond in a somewhat predictable way after a land use conversion event by shifting from communities reflecting their former land use towards those reflecting their current land use. Our findings help us to better understand the legacy effects of land use change on soil microbial communities and implications for their role in soil health and ecosystem functioning. Understanding the responsiveness of microbial communities to environmental disturbances will aid us in incorporating biotic variables into soil health monitoring techniques in the future.

3.
Nature ; 605(7911): 663-668, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35614248

RESUMO

Future quantum internet applications will derive their power from the ability to share quantum information across the network1,2. Quantum teleportation allows for the reliable transfer of quantum information between distant nodes, even in the presence of highly lossy network connections3. Although many experimental demonstrations have been performed on different quantum network platforms4-10, moving beyond directly connected nodes has, so far, been hindered by the demanding requirements on the pre-shared remote entanglement, joint qubit readout and coherence times. Here we realize quantum teleportation between remote, non-neighbouring nodes in a quantum network. The network uses three optically connected nodes based on solid-state spin qubits. The teleporter is prepared by establishing remote entanglement on the two links, followed by entanglement swapping on the middle node and storage in a memory qubit. We demonstrate that, once successful preparation of the teleporter is heralded, arbitrary qubit states can be teleported with fidelity above the classical bound, even with unit efficiency. These results are enabled by key innovations in the qubit readout procedure, active memory qubit protection during entanglement generation and tailored heralding that reduces remote entanglement infidelities. Our work demonstrates a prime building block for future quantum networks and opens the door to exploring teleportation-based multi-node protocols and applications2,11-13.

4.
Eur Spine J ; 31(5): 1206-1218, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35224672

RESUMO

PURPOSE: No clear consensus exists on which anterior surgical technique is most cost-effective for treating cervical degenerative disk disease (CDDD). One of the most common treatment options is anterior cervical discectomy with fusion (ACDF). Anterior cervical discectomy with arthroplasty (ACDA) was developed in an effort to reduce the incidence of clinical adjacent segment pathology and associated additional surgeries by preserving motion. This systematic review aims to evaluate the evidence regarding the cost-effectiveness of anterior surgical decompression techniques used to treat radiculopathy and/or myelopathy caused by CDDD. METHODS: The search was conducted in PubMed, EMBASE, Web of Science, CINAHL, EconLit, NHS-EED and the Cochrane Library. Studies were included if healthcare costs and utility or effectivity measurements were mentioned. RESULTS: A total of 23 studies were included out of the 1327 identified studies. In 9 of the 13 studies directly comparing ACDA and ACDF, ACDA was the most cost-effective technique, with an incremental cost effectiveness ratio ranging from $2.900/QALY to $98.475/QALY. There was great heterogeneity between the costs of due to different in- and exclusion criteria of costs and charges, cost perspective, baseline characteristics, and calculation methods. The methodological quality of the included studies was moderate. CONCLUSION: The majority of studies report ACDA to be a more cost-effective technique in comparison with ACDF. The lack of uniform literature impedes any solid conclusions to be drawn. There is a need for high-quality cost-effectiveness research and uniformity in the conduct, design and reporting of economic evaluations concerning the treatment of CDDD. TRIAL REGISTRATION: PROSPERO Registration: CRD42020207553 (04.10.2020).


Assuntos
Degeneração do Disco Intervertebral , Fusão Vertebral , Vértebras Cervicais/cirurgia , Análise Custo-Benefício , Discotomia/métodos , Humanos , Degeneração do Disco Intervertebral/cirurgia , Fusão Vertebral/métodos , Resultado do Tratamento
5.
Science ; 372(6539): 259-264, 2021 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-33859028

RESUMO

The distribution of entangled states across the nodes of a future quantum internet will unlock fundamentally new technologies. Here, we report on the realization of a three-node entanglement-based quantum network. We combine remote quantum nodes based on diamond communication qubits into a scalable phase-stabilized architecture, supplemented with a robust memory qubit and local quantum logic. In addition, we achieve real-time communication and feed-forward gate operations across the network. We demonstrate two quantum network protocols without postselection: the distribution of genuine multipartite entangled states across the three nodes and entanglement swapping through an intermediary node. Our work establishes a key platform for exploring, testing, and developing multinode quantum network protocols and a quantum network control stack.

6.
Spectrochim Acta A Mol Biomol Spectrosc ; 240: 118612, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32604047

RESUMO

In this study we present the crystal structure, spectroscopic and thermal behavior, Hirshfeld surface analysis, and DFT calculations of a new organic-inorganic hybrid compound (C7H8N3)2[CoCl4]. This compound crystallizes in the centrosymmetric space group P1¯. Single-crystal X-ray diffraction analysis indicates that structure consists of a succession of mixed layers formed by organic cations and inorganic anions parallel to the (001) plane and propagate according to the c-axis. Layers further are assembled into a 3D supramolecular architecture through N-H…Cl hydrogen bonds and π…π interactions. The peak positions of the experimental PXRD pattern are in agreement with the simulated ones from the crystal structure, indicating phase purity of the title compound. The presence of the different functional groups and the nature of their vibrations were identified by ATR-FTIR and FT-Raman spectroscopies. The tetrahedral environment of Co2+ was confirmed by UV-visible spectroscopy, where the spectrum shows three weak absorption bands in the visible range due to d-d electronic transitions 4A2(F) → 4T2(F), 4A2(F) → 4T1(F) and 4A2(F) → 4T1(P) typical of Co(II) coordination compounds. The direct and indirect optical band gap values were determined by Tauc method. The optimized structure and calculated vibrational frequencies were obtained by density functional theory (DFT) using B3LYP functional. TGA and DSC coupled to mass spectrometry (MS) experiments under argon atmosphere in the temperature range (25-950 °C) were carried out in order to determine the thermal stability of the title compound.

7.
Int J Tuberc Lung Dis ; 24(5): 477-484, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32398196

RESUMO

BACKGROUND: Tuberculosis incidence varies seasonally in many settings. However, the role of seasonal variation in reactivation vs. transmission is unclear.METHODS: We reviewed data on TB notifications in Cape Town, South Africa, from 1903 to 2017 (exclusive of 1995-2002, which were unavailable). Data from 2003 onward were stratified by HIV status, age and notification status (new vs. retreatment). We performed seasonal decomposition and time-dependent spectral analysis using wavelets to assess periodicity over time. We estimated monthly peak-to-peak seasonal amplitude of notifications as a percentage of the annual notification rate.RESULTS: A seasonal trend was intermittently detected between 1904 and 1994, particularly during periods of high notification rates, but was consistently and strongly evident between 2003 and 2017, with peaks in September through November, following winter. Among young children, a second, higher seasonal peak was observed in March. Seasonal variation was greater in children (<5 years, 54%, 95% CI 47-61; 5-14 years, 63%, 95% CI 58-69) than in adults (36%, 95% CI 33-39).CONCLUSIONS: Stronger seasonal effects were seen in children, in whom progression following recent infection is known to be the predominant driver of disease. These findings may support increased transmission in the winter as an important driver of TB in Cape Town.


Assuntos
Tuberculose , Adulto , Criança , Pré-Escolar , Cidades , Humanos , Incidência , Estações do Ano , África do Sul/epidemiologia , Tuberculose/tratamento farmacológico , Tuberculose/epidemiologia
8.
Opt Express ; 27(10): 14423-14436, 2019 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-31163892

RESUMO

Recently, a color appearance model, CAM18sl, has been published. The model can predict the color perception (hue, colorfulness, brightness) of self-luminous stimuli seen against neutral backgrounds varying in luminance. In this paper, the applicability of CAM18sl to situations different from the one for which it was originally developed is explored. The brightness perception predicted by this model (expressed in "bright") is compared with the outcome of the CIE Unified Glare Rating (UGR) for luminaires, the limiting luminance values for Variable Message Signs as indicated in the European standard for outdoor situations, the visual gloss (VG) formula to characterize the gloss of objects, the CIE grey-scale calculation for self-luminous devices, and the predicted brightness value of illuminated objects according to CIECAM02. Although the application domains mentioned above are very distinct, it appears that the predicted brightness perception of the CAM18sl model correlates well with the outcome of the particular and dedicated metrics. It seems that, for brightness perception, CAM18sl can be considered as a general model applicable for a wide range of applications. This could lead to a reduction of a number of application-specific metrics.

9.
Neth Heart J ; 27(4): 176-184, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30742250

RESUMO

BACKGROUND: Although decision-making using the heart-team approach is apparently intuitive and has a class I recommendation in most recent guidelines, supportive data is still lacking. The current study aims to demonstrate the individualised clinical pathway for mitral valve disease patients and to evaluate the outcome of all patients referred to the dedicated mitral valve heart team. METHODS: All patients who were evaluated for mitral valve pathology with or without concomitant cardiac disease between 1 January 2016 and 31 December 2016 were prospectively followed and included. Patients were evaluated, and a treatment strategy was determined by the dedicated mitral valve heart team. RESULTS: One hundred and fifty-eight patients were included; 67 patients were treated surgically (isolated and concomitant surgery), 20 by transcatheter interventions and 71 conservatively. Surgically treated patients had a higher 30-day mortality rate (4.4%), which decreased when specified to a dedicated surgeon (1.7%) and in primary, elective cases (0%). This was also observed for major adverse events within 30 days. Residual mitral regurgitation >grade 2 was more frequent in the catheter-based intervention group (23.5%) compared to the surgical group (4.8%). CONCLUSION: In conclusion, the implementation of a multidisciplinary heart team for mitral valve disease is a valuable approach for the selection of patients for different treatment modalities. Our research group will focus on a future comparative study using historical cohorts to prove the potential superiority of the dedicated multidisciplinary heart-team approach.

10.
J Opt Soc Am A Opt Image Sci Vis ; 35(12): 2000-2009, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30645289

RESUMO

A model for brightness and hue perception of self-luminous stimuli surrounded by a self-luminous achromatic background has been developed based on a series of visual experiments. In the model, only the absolute spectral radiance values of the stimulus and background are used as input. Normalized cone excitations are calculated using the 10° Commission Internationale de l'Éclairage (CIE) 2006 cone fundamentals. A von Kries chromatic adaptation transform applied in the CIE 2006 cone space is adopted, and luminance compression and adaptation due to the self-luminous background are included by using a Michaelis-Menten function. Model parameters are determined by fitting the model to the experimental visual data obtained for brightness, hue, and the amount of color versus neutral. The model is validated with additional experimental data. An absolute brightness scale expressed in "bright" is proposed.

11.
Infection ; 45(5): 669-676, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28349491

RESUMO

There is a paucity of data on the immune reconstitution inflammatory syndrome (IRIS) in the Central African region. We followed ART-naive HIV-infected patients initiating antiretroviral therapy in an HIV clinic in Gabon, for 6 months. Among 101 patients, IRIS was diagnosed in five. All IRIS cases were mucocutaneous manifestations. There were no cases of tuberculosis (TB) IRIS, but active TB (n = 20) was associated with developing other forms of IRIS (p = 0.02). Six patients died. The incidence of IRIS is low in Gabon, with mild, mucocutaneous manifestations.


Assuntos
Antirretrovirais/efeitos adversos , Infecções por HIV/tratamento farmacológico , Síndrome Inflamatória da Reconstituição Imune/epidemiologia , Adulto , Feminino , Gabão/epidemiologia , Humanos , Síndrome Inflamatória da Reconstituição Imune/induzido quimicamente , Síndrome Inflamatória da Reconstituição Imune/etiologia , Síndrome Inflamatória da Reconstituição Imune/imunologia , Incidência , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Tuberculose/complicações
12.
S Afr Med J ; 106(12): 1263-1269, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-27917775

RESUMO

BACKGROUND: Tuberculosis (TB) control programmes rely mainly on passive detection of symptomatic individuals. The resurgence of TB has rekindled interest in active case finding. Cape Town (South Africa) had a mass miniature radiography (MMR) screening programme from 1948 to 1994. OBJECTIVE: To evaluate screening coverage, yield and secular trends in TB notifications during the MMR programme. METHODS: We performed an ecological analysis of the MMR programme and TB notification data from the City of Cape Town Medical Officer of Health reports for 1948 - 1994. RESULTS: Between 1948 and 1962, MMR screening increased to 12% of the population per annum with yields of 14 cases per 1 000 X-rays performed, accounting for >20% of total annual TB notifications. Concurrent with increasing coverage (1948 - 1965), TB case notification decreased in the most heavily TB-burdened non-European population from 844/100 000 population to 415/100 000. After 1966, coverage declined and TB notifications that initially remained stable (1967 - 1978) subsequently increased to 525/100 000. MMR yields remained low in the European population but declined rapidly in the non-European population after 1966, coincidental with forced removals from District 6. An inverse relationship between screening coverage and TB notification rates was observed in the non-European adult population. Similar secular trends occurred in infants and young children who were not part of the MMR screening programme. CONCLUSION: MMR of a high-burdened population may have significantly contributed to TB control and was temporally associated with decreased transmission to infants and children. These historical findings emphasise the importance of re-exploring targeted active case finding strategies as part of population TB control.

13.
Int J Tuberc Lung Dis ; 20(9): 1185-91, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27510244

RESUMO

SETTING: Cape Town, South Africa. OBJECTIVE: To evaluate anti-tuberculosis treatment outcomes and rate of antiretroviral therapy (ART) initiation using weekly community-based adherence support compared to daily directly observed therapy (DOT). METHODS: This was a retrospective analysis comparing two cohorts treated for tuberculosis (TB) in 70 TB clinics during 6-month periods before and after the introduction of a new adherence model comprising treatment literacy sessions during 2 weeks of DOT, followed by weekly home visits by community care workers to eligible patients managing their own treatment. Odds ratios (ORs) of treatment success and ART initiation were calculated using multivariable random effects logistic regression models. Hazard ratios (HRs) of default and death were calculated using multivariable random effects Cox regression models. RESULTS: The pre-intervention cohort comprised 11 896 patients with TB and the post-intervention cohort 11 314. There was no difference in pre- and post-intervention anti-tuberculosis treatment success rates (respectively 82.8% and 82.5%, adjusted OR [aOR] 1.02, 95%CI 0.89-1.17, P = 0.76) nor an increased hazard of death (adjusted HR [aHR] 0.98, 95%CI 0.80-1.21, P = 0.87) or default (aHR 0.97, 95%CI 0.81-1.15, P = 0.69). The ART initiation rate increased from 67% to 74% (aOR 1.43; 95%CI 1.01-1.85, P < 0.01). CONCLUSION: Weekly community-based adherence support was a viable alternative to daily DOT, with no deterioration in anti-tuberculosis treatment outcomes and an increase in ART initiation.


Assuntos
Agentes Comunitários de Saúde , Terapia Diretamente Observada , Infecções por HIV/tratamento farmacológico , Adesão à Medicação , Tuberculose/tratamento farmacológico , Adulto , Fármacos Anti-HIV/uso terapêutico , Antituberculosos/uso terapêutico , Feminino , Humanos , Modelos Logísticos , Masculino , Modelos de Riscos Proporcionais , África do Sul , Resultado do Tratamento , Adulto Jovem
15.
HIV Med ; 13(6): 337-44, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22296211

RESUMO

OBJECTIVES: High early mortality after antiretroviral therapy (ART) initiation in resource-limited settings is associated with low baseline CD4 cell counts and a high burden of opportunistic infections. Our large urban HIV clinic in Uganda has made concerted efforts to initiate ART at higher CD4 cell counts and to improve diagnosis and care of patients coinfected with tuberculosis (TB). We sought to determine associated treatment outcomes. METHODS: Routinely collected data for all patients who initiated ART from 2005 to 2009 were analysed. Median baseline CD4 cell counts by year of ART initiation were compared using the Cuzick test for trend. Mortality and TB incidence rates in the first year of ART were computed. Hazard ratios (HRs) were calculated using multivariable Cox proportional hazards models. RESULTS: First-line ART was initiated in 7659 patients; 64% were women, and the mean age was 37 years (standard deviation 9 years). Median baseline CD4 counts increased from 2005 to 2009 [82 cells/µL (interquartile range (IQR) 24, 153) to 148 cells/µL (IQR 61, 197), respectively; P<0.001]. The mortality rate fell from 6.5/100 person-years at risk (PYAR) [95% confidence interval (CI) 5.5-7.6 PYAR] to 3.6/100 PYAR (95% CI 2.2-5.8 PYAR). TB incidence rates increased from 8.2/100 PYAR (95% CI 7.1-9.5 PYAR) to 15.6/100 PYAR (95% CI 12.4-19.7 PYAR). A later year of ART initiation was independently associated with decreased mortality (HR 0.91; 95% CI 0.83-1.00; P=0.04). CONCLUSIONS: Baseline CD4 cell counts have increased over time and are associated with decreased mortality. Additional reductions in mortality might be a result of a better standard of care and increased TB case finding. Further efforts to initiate ART earlier should be prioritized even in a setting of capped or reduced funding for ART programmes.


Assuntos
Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Síndrome da Imunodeficiência Adquirida/epidemiologia , Fármacos Anti-HIV/uso terapêutico , Tuberculose/epidemiologia , Infecções Oportunistas Relacionadas com a AIDS/tratamento farmacológico , Infecções Oportunistas Relacionadas com a AIDS/imunologia , Síndrome da Imunodeficiência Adquirida/imunologia , Adulto , Contagem de Linfócito CD4 , Estudos de Coortes , Feminino , Humanos , Incidência , Masculino , Estudos Retrospectivos , Tuberculose/tratamento farmacológico , Tuberculose/imunologia , Uganda/epidemiologia , População Urbana/estatística & dados numéricos
16.
Neth Heart J ; 18(7-8): 384, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20730012
17.
Ned Tijdschr Geneeskd ; 148(33): 1636-41, 2004 Aug 14.
Artigo em Holandês | MEDLINE | ID: mdl-15455512

RESUMO

Three patients, a woman aged 32, a boy aged 6.5 and a man aged 56 years, presented with a subcutaneous mass suggesting a malignancy: respectively a rubbery swelling, painful to the touch below the left scapula, a partly massive, partly soft swelling on the inside of the left upper leg, and a non-fluctuating mass near the right eighth rib, parasternally. Additional diagnostic investigation revealed an infectious cause: respectively Mycobacterium tuberculosis, Bartonella henselae and Salmonella typhi. Antimicrobial therapy was successful. Subcutaneous masses suspected of being a benign or malignant tumour are sometimes caused by an infection. The differential diagnosis is extensive. Sometimes the travel anamnesis yields helpful information. It is concluded that besides histopathological examination, microbiological investigation can play a major role in the evaluation of subcutaneous masses.


Assuntos
Bartonella henselae/isolamento & purificação , Doença da Arranhadura de Gato/diagnóstico , Infecções por Salmonella/diagnóstico , Tuberculose/diagnóstico , Adulto , Antibacterianos/uso terapêutico , Doença da Arranhadura de Gato/tratamento farmacológico , Criança , Diagnóstico Diferencial , Feminino , Humanos , Perna (Membro)/microbiologia , Perna (Membro)/patologia , Masculino , Pessoa de Meia-Idade , Mycobacterium tuberculosis/isolamento & purificação , Costelas/microbiologia , Costelas/patologia , Infecções por Salmonella/tratamento farmacológico , Salmonella typhi/isolamento & purificação , Ombro/microbiologia , Ombro/patologia , Tuberculose/tratamento farmacológico
19.
Eur J Biochem ; 235(1-2): 73-81, 1996 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-8631369

RESUMO

The aim of the present study was to assess the origin of the 1,2-diradylglycerols produced during prolonged hormonal stimulation of rabbit pancreatic acini by comparison of their relative molecular species composition with that of the major acinar phospholipids. Both phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdEtn) consisted of 1,2-diacyl as well as 1-alk-1-2-acyl species. In contrast, phosphatidylinositol (PtdIns), phosphatidylserine and phosphatidic acid existed only in the 1,2-diacyl form. Acinar cells did not contain detectable amounts of 1-alkyl-2-acyl phospholipids. Similarly, the acinar 1,2-diradylglycerol fraction consisted of 1,2-diacylglycerols and 1-alk-1-enyl-2-acylglycerols. Mass 1,2-diradylglycerol measurements revealed that prolonged stimulation with cholecystokinin resulted in a marked and sustained increase in acinar 1,2-diradylglycerol content. Based on the relative amounts of the 1,2-diacyl species present in both the 1,2-diradylglycerol fraction and the individual phospholipids, it is calculated that under control conditions 60% of the 1,2-diacylglycerols originate from PtdCho and 40% from PtdIns, whereas under stimulatory conditions 53% is calculated to be derived from PtdCho, 46% from PtdIns and 1% from PtdEtn. Likewise, it is calculated that in control as well as stimulated acini 100% of the 1-alk-l-enyl-2-acylglycerols originate from plasmenylcholine. Further evidence in favour of the idea that at least a considerable part of the 1,2-diacylglycerols produced during prolonged hormonal stimulation originate from inositolphospholipids is provided by the observation that labeling of phosphatidylinositol 4,5-bisphosphate with inorganic phosphate reached isotopic equilibrium markedly faster under stimulatory conditions as compared to the control situation, which is in agreement with an elevated turnover rate. The data presented support the idea that PtdCho and inositolphospholipids are the major precursors in basal and stimulated 1,2-diradylglycerol production in rabbit pancreatic acini.


Assuntos
Diglicerídeos/biossíntese , Pâncreas/efeitos dos fármacos , Pâncreas/metabolismo , Fosfolipídeos/metabolismo , Sincalida/análogos & derivados , Animais , Diglicerídeos/química , Técnicas In Vitro , Cinética , Estrutura Molecular , Fosfatidilcolinas/metabolismo , Fosfatidilinositóis/metabolismo , Fosfolipídeos/química , Fosfolipídeos/classificação , Coelhos , Sincalida/farmacologia
20.
Blood ; 81(9): 2413-9, 1993 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-8481520

RESUMO

Eosinophils are important in antibody-mediated immune defense against parasites based on interaction with Ig receptors (FcR). Of the three classes of IgG FcR in humans, hFc gamma RI, II, and III, solely hFc gamma RII (CD32) is expressed on freshly isolated eosinophils. Despite an expression level similar to that found on monocytes and polymorphonuclear granulocytes, binding activity of hFc gamma RII on eosinophils is constitutively low. Freshly isolated eosinophils had a negligible ability to form rosettes with IgG-sensitized erythrocytes (EA-IgG). Addition of granulocyte-macrophage colony-stimulating factor (GM-CSF) caused an approximately threefold increase in EA-IgG rosettes. This increase was maximal after 35 minutes, and declined upon further incubation at 37 degrees C. Analysis of hFc gamma RII expression levels showed no significant changes and neither was the expression of other hFc gamma R classes induced. Blocking studies with anti-Fc gamma receptor monoclonal antibody (MoAb) proved hFc gamma RII specificity of enhanced IgG complex binding. These phenomena were not restricted to GM-CSF action, because the addition of interleukin-3 or interleukin-5 similarly enhanced EA-IgG binding. The kinetics of activation of hFc gamma RII binding activity were paralleled by the binding of EA-C3bi to CR3 on eosinophils. In contrast to the stable expression of hFc gamma RII during activation with GM-CSF, CR3 expression increased slowly. Ligand binding via both types of opsonin receptors proved receptor specific. However, the kinetics of enhanced binding via hFc gamma RII and CR3 suggested the possibility of a common mechanism underlying the enhancement of ligand binding via hFc gamma RII and CR3. This hypothesis was supported by the fact that binding via hFc gamma RII proved sensitive to both high concentrations of F(ab')2 fragments of anti-CD11b MoAb MO1 and chelation of bivalent cations with EDTA. In conclusion, our studies indicate that cytokines can induce a transient enhancement of hFc gamma RII binding activity. Qualitative, and not quantitative, changes in this receptor appear to underly the modulation of binding activity, which may be linked to changes in CR3 activity.


Assuntos
Citocinas/farmacologia , Eosinófilos/fisiologia , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Receptores de IgG/fisiologia , Células Cultivadas , Eosinófilos/efeitos dos fármacos , Eosinófilos/imunologia , Eritrócitos/imunologia , Eritrócitos/fisiologia , Humanos , Interleucina-3/farmacologia , Interleucina-5/farmacologia , Cinética , Fator de Ativação de Plaquetas/farmacologia , Receptores de IgG/efeitos dos fármacos , Proteínas Recombinantes/farmacologia , Formação de Roseta , Fatores de Tempo
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