Your browser doesn't support javascript.
loading
Montrer: 20 | 50 | 100
Résultats 1 - 16 de 16
Filtrer
1.
Vaccines (Basel) ; 10(11)2022 Nov 19.
Article de Anglais | MEDLINE | ID: mdl-36423061

RÉSUMÉ

COVID-19 and metabolic syndrome, though seemingly different disorders, appear to share certain common pathogenic components, especially in the development of COVID-19-associated diabetes mellitus. The similarities include impairment in immunoendothelial, gastrointestinal, pancreatic, adipose and mitochondrial functions, with several critical micronutrients undergirding the intricate interactions among these dysfunctions. This discussion aims to highlight the parallels between COVID-19 and metabolic syndrome and to propose the possibility of SARS-CoV-2 being a prototype of an acquired etiological agent which can eventually lead to the development of classical metabolic syndrome. Based on the proposed model, the discussion will include the implication for early management of COVID-19 and metabolic syndrome.

3.
Cancer Immunol Immunother ; 71(6): 1531-1543, 2022 Jun.
Article de Anglais | MEDLINE | ID: mdl-34661709

RÉSUMÉ

INTRODUCTION: Epstein-Barr virus (EBV) is associated with nasopharyngeal carcinoma (NPC), and provides a target for a dendritic cell (DC) vaccine. CD137 ligand (CD137L) expressed on antigen presenting cells, costimulates CD137-expressing T cells, and reverse CD137L signaling differentiates monocytes to CD137L-DC, a type of DC, which is more potent than classical DC in stimulating T cells. METHODS: In this phase I study, patients with locally recurrent or metastatic NPC were administered CD137L-DC pulsed with EBV antigens (CD137L-DC-EBV-VAX). RESULTS: Of the 12 patients treated, 9 received full 7 vaccine doses with a mean administered cell count of 23.9 × 106 per dose. Treatment was well tolerated with only 4 cases of grade 1 related adverse events. A partial response was obtained in 1 patient, and 4 patients are still benefitting from a progression free survival (PFS) of currently 2-3 years. The mean pre-treatment neutrophil: lymphocyte ratio was 3.4 and a value of less than 3 was associated with prolonged median PFS. Progressors were characterized by a high frequency of naïve T cells but a low frequency of CD8+ effector T cells while patients with a clinical benefit (CB) had a high frequency of memory T cells. Patients with CB had lower plasma EBV DNA levels, and a reduction after vaccination. CONCLUSION: CD137L-DC-EBV-VAX was well tolerated. The use of CD137L-DC-EBV-VAX is demonstrated to be safe. Consistent results were obtained from all 12 patients, indicating that CD137L-DC-EBV-VAX induces an anti-EBV and anti-NPC immune response, and warranting further studies in patients post effective chemotherapy. PRECIS: The first clinical testing of CD137L-DC, a new type of monocyte-derived DC, finds that CD137L-DC are safe, and that they can induce an immune response against Epstein-Barr virus-associated nasopharyngeal carcinoma that leads to tumor regression or prevents tumor progression.


Sujet(s)
Infections à virus Epstein-Barr , Tumeurs du rhinopharynx , Ligand de 4-1BB/génétique , Cellules dendritiques , Herpèsvirus humain de type 4 , Humains , Cancer du nasopharynx/thérapie , Tumeurs du rhinopharynx/thérapie
4.
Nutrition ; 79-80: 111017, 2020.
Article de Anglais | MEDLINE | ID: mdl-33039952

RÉSUMÉ

OBJECTIVES: The aim of this study was to determine clinical outcomes of older patients with coronavirus (COVID-19) who received a combination of vitamin D, magnesium, and vitamin B12 (DMB) compared with those who did not. We hypothesized that fewer patients administered this combination would require oxygen therapy, intensive care support, or a combination of both than those who did not. METHODS: This was a cohort observational study of all consecutive hospitalized patients ≥50 y of age with COVID-19 in a tertiary academic hospital. Before April 6, 2020, no patients received the (DMB) combination. After this date, patients were administered 1000 IU/d oral vitamin D3, 150 mg/d oral magnesium, and 500 mcg/d oral vitamin B12 upon admission if they did not require oxygen therapy. Primary outcome was deterioration leading to any form of oxygen therapy, intensive care support, or both. RESULTS: Between January 15 and April 15, 2020, we identified 43 consecutive patients ≥50 y of age with COVID-19. Seventeen patients received DMB before onset of primary outcome and 26 patients did not. Baseline demographic characteristics between the two groups were significantly different by age. In univariate analysis, age and hypertension had a significant influence on outcome. After adjusting for age or hypertension separately in a multivariate analysis, the intervention group retained protective significance. Fewer treated patients than controls required initiation of oxygen therapy during hospitalization (17.6 vs 61.5%, P = 0.006). DMB exposure was associated with odds ratios of 0.13 (95% confidence interval [CI], 0.03-0.59) and 0.20 (95% CI, 0.04-0.93) for oxygen therapy, intensive care support, or both on univariate and multivariate analyses, respectively. CONCLUSIONS: A vitamin D / magnesium / vitamin B12 combination in older COVID-19 patients was associated with a significant reduction in the proportion of patients with clinical deterioration requiring oxygen support, intensive care support, or both. This study supports further larger randomized controlled trials to ascertain the full benefit of this combination in ameliorating the severity of COVID-19.


Sujet(s)
Traitements médicamenteux de la COVID-19 , Soins de réanimation , Magnésium/usage thérapeutique , Micronutriments/usage thérapeutique , Oxygénothérapie , Vitamine B12/usage thérapeutique , Vitamine D/usage thérapeutique , Sujet âgé , COVID-19/thérapie , Études de cohortes , Évolution de la maladie , Femelle , Hospitalisation , Humains , Mâle , Adulte d'âge moyen , Minéraux/usage thérapeutique , Analyse multifactorielle , Pandémies , SARS-CoV-2 , Indice de gravité de la maladie , Vitamines/usage thérapeutique
6.
Lab Med ; 50(4): e59-e69, 2019 Oct 10.
Article de Anglais | MEDLINE | ID: mdl-31051501

RÉSUMÉ

BACKGROUND: Timely blood delivery to patients with critical bleeding poses logistic challenges. A modern, high speed hospital pneumatic tube system (PTS) is one solution, but blood units may be subjected to high-speed torque and acceleration/deceleration forces. OBJECTIVE: To validate a new PTS system for potential use at our 1,400-bed hospital in Singapore. METHOD: Our validation included red blood cells, platelets, thawed plasma, and cryoprecipitate units transported from the blood bank for a distance of 820 meters (PTS track), at a velocity of 3-6 meters per second. Transit time, temperature, bag integrity, and blood quality were assessed visually and through analytical testing on pre- and post-PTS specimens. RESULTS: Blood units arrived physically intact in less than 8 minutes. The temperature for each was within the acceptable range. Comparative testing of pre-PTS and post-PTS specimens showed no significant difference in physical quality and analyzed parameters (P> .05). CONCLUSIONS: High speed PTS transportation of blood components has satisfactory fidelity and speed, without significant impact on quality. As a result, we incorporated PTS blood delivery into the hospital massive-transfusion protocol and successfully operationalized that new system.


Sujet(s)
Produits biologiques/ressources et distribution , Transfusion sanguine/méthodes , Services des urgences médicales/méthodes , Hémorragie/thérapie , Transports/méthodes , Maladie grave , Humains , Singapour
7.
Immunobiology ; 224(4): 526-531, 2019 07.
Article de Anglais | MEDLINE | ID: mdl-31072628

RÉSUMÉ

Simulated Infective Protocol (SIP) is an ex-vivo culture system modeled after the temporal changes of essential cytokines in an acute infection, and previously proven successful in converting T lymphocytes harvested and activated from peripheral blood of normal donors, to revertant CD45RA + Central Memory T lymphocytes (Tcmra) demonstrating properties akin to T Memory Stem Cells (Tscm). In this study, we applied similar SIP on tumor infiltrating lymphocytes (TIL) from bone marrow of patients diagnosed with acute myeloid leukemia (AML), and replicated the feasibility to convert activated TILs into Tcmra phenotype. These revertant Tcmra lymphocytes re-expressed CD45RA+, CCR7+, CD62L + and CD127+, shown improved survivability with longer telomere length, expressed memory properties including higher Eomes to Tbet ratio, and exhibited cytotoxicity against autologous AML blast cells.


Sujet(s)
Mémoire immunologique , Leucémie aigüe myéloïde/immunologie , Leucémie aigüe myéloïde/métabolisme , Antigènes CD45/métabolisme , Activation des lymphocytes/immunologie , Lymphocytes TIL/immunologie , Lymphocytes TIL/métabolisme , Marqueurs biologiques , Cellules cultivées , Humains , Immunophénotypage , Leucémie aigüe myéloïde/anatomopathologie , Numération des lymphocytes , Lymphocytes TIL/anatomopathologie
10.
J Immunother ; 38(6): 250-8, 2015.
Article de Anglais | MEDLINE | ID: mdl-26049548

RÉSUMÉ

Adoptive cell therapy is an emerging treatment strategy for a number of serious diseases. Regulatory T (Treg) cells represent 1 cell type of particular interest for therapy of inflammatory conditions, as they are responsible for controlling unwanted immune responses. Initial clinical trials of adoptive transfer of Treg cells in patients with graft-versus-host disease were shown to be safe. However, obtaining sufficient numbers of highly pure and functional Treg cells with minimal contamination remains a challenge. We developed a novel approach to isolate "untouched" human Treg cells from healthy donors on the basis of negative selection using the surface markers CD49d and CD127. This procedure, which uses an antibody cocktail and magnetic beads for separation in an automated system (RoboSep), was scaled up and adapted to be compatible with good manufacturing practice conditions. With this setup we performed 9 Treg isolations from large-scale leukapheresis samples in a good manufacturing practice facility. These runs yielded sufficient numbers of "untouched" Treg cells for immediate use in clinical applications. The cell preparations consisted of viable highly pure FoxP3-positive Treg cells that were functional in suppressing the proliferation of effector T cells. Contamination with CD4 effector T cells was <10%. All other cell types did not exceed 2% in the final product. Remaining isolation reagents were reduced to levels that are considered safe. Treg cells isolated with this procedure will be used in a phase I clinical trial of adoptive transfer into leukemia patients developing graft-versus-host disease after stem cell transplantation.


Sujet(s)
Séparation cellulaire/méthodes , Maladie du greffon contre l'hôte/prévention et contrôle , Immunothérapie adoptive , Leucémies/thérapie , Transplantation de cellules souches , Sous-populations de lymphocytes T/immunologie , Lymphocytes T régulateurs/immunologie , Survie cellulaire , Cellules cultivées , Essais cliniques comme sujet , Facteurs de transcription Forkhead/métabolisme , Maladie du greffon contre l'hôte/étiologie , Maladie du greffon contre l'hôte/immunologie , Humains , Immunosuppression thérapeutique , Intégrine alpha4/métabolisme , Sous-unité alpha du récepteur à l'interleukine-7/métabolisme , Leucémies/complications , Leucémies/immunologie , Lymphocytes T régulateurs/transplantation
11.
Br J Haematol ; 165(1): 134-44, 2014 Apr.
Article de Anglais | MEDLINE | ID: mdl-24428589

RÉSUMÉ

CD137 ligand (CD137L), a member of the tumour necrosis factor family, is expressed as a cell surface molecule. Engagement of CD137L on haematopoietic progenitor cells induces monocytic differentiation, and in peripheral monocytes CD137L signalling promotes differentiation to mature dendritic cells. We hypothesized that CD137L signalling would also induce differentiation in transformed myeloid cells. Here we show that recombinant CD137 protein, which crosslinks CD137L and initiates reverse CD137L signalling in myeloid cells, induces morphological changes (adherence, spreading), loss of progenitor markers (CD117), expression of maturation markers (CD11b, CD13) and secretion of cytokines that are indicative of myeloid differentiation. Under the influence of CD137L signalling, acute myeloid leukaemia (AML) cells acquired expression of co-stimulatory molecules (CD80, CD86, CD40), the dendritic cell marker CD83 and dendritic cell activities, enabling them to stimulate T cells. CD137L signalling induced differentiation in 71% (15 of 21) of AML samples, irrespective of French-American-British classification and CD137L expression level. However, the type of response varied with the AML subtype and patient sample. In summary, this study demonstrated that CD137L signalling induced differentiation in malignant cells of AML patients, and suggests that it may be worthwhile to investigate treatment with recombinant CD137 protein as a potential novel therapeutic approach for AML.


Sujet(s)
Ligand de 4-1BB/métabolisme , Différenciation cellulaire , Leucémie aigüe myéloïde/métabolisme , Transduction du signal , Adulte , Sujet âgé , Antigènes CD/métabolisme , Humains , Immunophénotypage , Leucémie aigüe myéloïde/diagnostic , Adulte d'âge moyen , Liaison aux protéines , Protéines de fusion recombinantes/métabolisme , Antigènes CD137/métabolisme , Jeune adulte
12.
J Immunol ; 191(11): 5603-14, 2013 Dec 01.
Article de Anglais | MEDLINE | ID: mdl-24184558

RÉSUMÉ

Central memory T lymphocytes were reported to develop after acute but not chronic infection, which prompted this feasibility study on generating long-term CD8 T cells ex vivo, by applying a culture condition that simulates an acute infection. During 35 d of culture, naive T cells (CD45RA(+), CD127(+), CCR7(+), CD62L(+), CXCR3(+)) first developed into effector T cells (CD45RA(+/-), CD127(+/-), CCR7(+/-), CD62L(+), CXCR3(+)), followed by three intermediate stages: intermediate T cells 1 (CD45RO(+), CD127(+/-), CCR7(+), CD62L(+), CXCR3(+)), intermediate T cells 2 (CD45RO(+), CD127(-), CCR7(-), CD62L(+), CXCR3(+)), and intermediate T cells 3 (CD45RO(+/-), CD127(+), CCR7(+), CD62L(-), CXCR3(+)) before reverting to stable CD45RA(+) central memory T cells (CD45RA(+), CD127(+), CCR7(+), CD62L(+), CXCR3(+)). If both anti-CD3 and the inflammatory milieu persisted beyond day 10, intermediate T cells 2 gradually developed into effector memory T cells (CD45RO(+), CD127(-), CCR7(-), CD62L(-), CXCR3(+)). Furthermore, intermediate T cells 2 or effector memory T cells, when cultured in persistent inflammatory cytokines devoid of anti-CD3, were converted to central memory T cells (CD45RO(+), CCR7(+), CD62L(+)). Overall, these results support ex vivo memory-like T lymphocyte production and favor a developmental pathway including both divergent and linear relationships.


Sujet(s)
Lymphocytes T CD8+/immunologie , Techniques de culture cellulaire/méthodes , Infections/immunologie , Maladie aigüe , Antigènes CD/métabolisme , Lymphocytes T CD8+/microbiologie , Différenciation cellulaire , Prolifération cellulaire , Séparation cellulaire , Cellules cultivées , Cytométrie en flux , Humains , Mémoire immunologique , Immunophénotypage , Récepteurs CCR7/métabolisme , Récepteurs CXCR3
13.
Ann Acad Med Singap ; 36(6): 431-4, 2007 Jun.
Article de Anglais | MEDLINE | ID: mdl-17597970

RÉSUMÉ

INTRODUCTION: We report a successful case of immune tolerance to factor VIII (FVIII) inhibitor after a major operation. An attempt was made to induce immune tolerance with inhibitor in a haemophilia A patient, who was required to undergo an above-knee amputation. We opted to give high-dose FVIII infusion with no immunosuppression. OUTCOME: The highest preoperative FVIII inhibitor level was 5 BU and the peak postoperative FVIII inhibitor level was 1.5 BU demonstrated on Day 9 post operation. High-dose FVIII support was provided during the perioperative period and continued with a low maintenance dose to achieve a FVIII level of 30% to 40%. The requirement of high-dose FVIII lasted from day 6 to 23 post operation and this was tailed down to a maintenance dose over the next 37 days. There were only 2 episodes of mild oozing from the wound at around Day 9, which coincided with the peak postoperative FVIII inhibitor level. Both bleeding episodes were arrested adequately by administering a single dose of FEIBA during each episode. Immune tolerance was demonstrated after around 3 months and a follow-up period of 233 days showed no recurrence of FVIII inhibitor with the normalisation of FVIII half-life study. CONCLUSION: After immune tolerance, the patient suffered fewer episodes of joint haemorrhage and required a lower amount of FVIII infusion as well. The cost may be high initially but the longterm cost-effectiveness has to be carefully evaluated.


Sujet(s)
Coagulants/immunologie , Facteur VIII/immunologie , Hémophilie A/complications , Tolérance immunitaire/effets des médicaments et des substances chimiques , Adulte , Amputation chirurgicale , Coagulants/administration et posologie , Facteur VIII/administration et posologie , Humains , Mâle , Soins périopératoires , Soins postopératoires
14.
Biomark Insights ; 2: 293-8, 2007 Aug 08.
Article de Anglais | MEDLINE | ID: mdl-19662212

RÉSUMÉ

UNLABELLED: Biomarkers provide certain values for diagnosis, monitor treatment efficacy, or for the development of novel therapeutic approach for particular diseases. Thus, the identification of specific of biomarkers for specific medical problems, including malignant diseases may be valuable in medical practice. In the study, we have used the Wilms' tumor gene (WT1) as a biomarker to evaluate its expression in local adult patients with newly diagnosed acute leukemia, including both acute myeloid and lymphoid leukemias (AML and ALL). AIM: To investigate WT1 gene expression in adult patients with acute leukemia at diagnosis. METHODS: Eighteen patients with acute leukemia diagnosed at Singapore General Hospital, Singapore, between September, 2004 and July, 2005 were included in this study. There were fifteen AML and three ALL cases aged from 18 to 71 years old. Total RNA and DNA was extracted from peripheral blood mononuclear cells (PBMCs). Expression of WT1 was detected by nested reverse-transcription polymerase chain reaction (Nested RT-PCR). K562, and 3T3 cells were used as positive- and negative-controls. The results were revalidated using real-time PCR. HLA-A genotyping was performed using sequence specific oligonucleotide polymorphism (SSOP) analysis. RESULTS: WT1 gene was exclusively expressed in all eighteen, including three ALL and fifteen AML, patients. In contrast with WT1 gene, the HLA-A genotyping was remarkably heterogeneous in these patients. CONCLUSIONS: WT1 gene expression was observed in local patients with acute leukemia at diagnosis. It may be used as a potential molecular marker for diagnosis, clinical progression of the diseases or monitoring the response to treatment, as well as a target for the development of novel therapeutic approaches.

15.
Hum Gene Ther ; 17(3): 362-75, 2006 Mar.
Article de Anglais | MEDLINE | ID: mdl-16544985

RÉSUMÉ

Adverse effects (death and leukemogenesis) from viral vector-mediated gene therapy have renewed interest in plasmids as safer, more scalable, simple, and cost-effective vectors. Electroporation and hydrodynamic delivery are two techniques that improve the efficiency of plasmid-mediated gene transfer. The liver is a good tissue platform for targeted transfer of therapeutically relevant genes for correction of metabolic disorders, for example, hemophilia A. However, in vivo electroporation of liver has not yet been shown to achieve therapeutic efficacy of systemically active, secreted transgenic proteins. We have investigated the effect of field strength, pulse duration, pulse number, electrical waveforms, electrode contact area, plasmid administration routes, and injection technique on the efficiency of in vivo electrotransfer of naked plasmid to liver. Plasmid injection into a systemic vein was superior to intrahepatic injection. Unlike in vivo muscle electroporation, high-voltage pulses and microsecond pulses offered no advantage. Optimal electroporation conditions were 8-10 uni- or bipolar pulses of 20 msec, each at 250 V/cm. Using a nonhydrodynamic technique that greatly enhanced electrotransfer efficiency with minimal tissue injury, we demonstrate for the first time that liverdirected in vivo electroporation of factor VIII cDNA achieved significant phenotypic correction in hemophilic mice.


Sujet(s)
Électroporation/méthodes , Facteur VIII/physiologie , Thérapie génétique , Vecteurs génétiques , Hémophilie A/thérapie , Foie/métabolisme , Plasmides , Animaux , Facteur VIII/génétique , Humains , Luciferases/génétique , Luciferases/métabolisme , Mâle , Souris , Souris de lignée BALB C , Souris knockout , Transgènes/physiologie , beta-Galactosidase/génétique , beta-Galactosidase/métabolisme
16.
J Gene Med ; 7(4): 494-505, 2005 Apr.
Article de Anglais | MEDLINE | ID: mdl-15521095

RÉSUMÉ

BACKGROUND: Hemophilia A treatment relies on costly factor VIII (FVIII) replacement that may transmit iatrogenic viral diseases. Viral vectors and cell implants are being developed as improvements. We investigated in vivo electroporation of naked DNA as a safe and simple method for correcting FVIII deficiency. METHODS: B-domain-deleted murine FVIII cDNA expression plasmids were constructed with CMV and elongation factor 1alpha promoters for characterisation in murine C2C12 myoblasts. The construct conferring highest in vitro FVIII secretion was electroporated into skeletal muscle of FVII null mice in vivo for phenotypic correction using a protocol that minimised tissue injury. RESULTS: B-domain-deleted murine FVIII cDNA plasmids induced FVIII secretion from stably transfected C2C12 myoblasts (0.54+/-0.20 mU/day/10(5) cells). Phenotypic correction of hemophilic mice was more consistently achieved using a protocol for in vivo electroporation of gastrocnemius muscle with FVIII cDNA that reduced tissue injury by the use of plate electrodes, hyaluronidase pre-treatment and lower field strength. This technique was associated with <10% muscle necrosis. Activated partial thromboplastin time decreased from 51.4+/-3.3 to 34.7+/-1.1 (mean+/-s.e.m.) seconds (p=0.0004) following in vivo electroporation (0.1 mg plasmid/limb; 8x20 ms pulses, 175 V/cm, 1 Hz) of hemophilic mice. All hemophilic mice (8/8) survived hemostatic challenge after muscle electroporation with FVIII cDNA, whereas all (9/9) untreated hemophilic mice died. Plasmid DNA was detectable only in electroporated muscle and not in all other organs tested, including gonads. CONCLUSION: In vivo intramuscular electroporation of naked FVIII plasmid successfully corrects murine hemophilia.


Sujet(s)
Électroporation , Facteur VIII/génétique , Thérapie génétique , Hémophilie A/thérapie , Muscles squelettiques/métabolisme , Animaux , Séquence nucléotidique , Lignée cellulaire , Milieux de culture conditionnés , Amorces ADN , Gènes rapporteurs , Souris , Phénotype , Plasmides
SÉLECTION CITATIONS
DÉTAIL DE RECHERCHE
...