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1.
Appl Radiat Isot ; 205: 111181, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38244325

RESUMO

PURPOSE: Body composition analysis using computed tomography (CT) is proposed as a predictor of cancer mortality. An association between subcutaneous adipose tissue radiodensity (SATr) and cancer-specific mortality was established, while gender effects and equipment bias were estimated. METHODS: 7,475 CT studies were selected from 17 cohorts containing CT images of untreated cancer patients who underwent follow-up for a period of 2.1-118.8 months. SATr measures were collected from published data (n = 6,718) or calculated according to CT images using a deep-learning network (n = 757). The association between SATr and mortality was ascertained for each cohort and gender using the p-value from either logistic regression or ROC analysis. The Kruskal-Wallis test was used to analyze differences between gender distributions, and automatic segmentation was evaluated using the Dice score and five-point Likert quality scale. Gender effect, scanner bias and changes in the Hounsfield unit (HU) to detect hazards were also estimated. RESULTS: Higher SATr was associated with mortality in eight cancer types (p < 0.05). Automatic segmentation produced a score of 0.949 while the quality scale measurement was good to excellent. The extent of gender effect was 5.2 HU while the scanner bias was 10.3 HU. The minimum proposed HU change to detect a patient at risk of death was between 5.6 and 8.3 HU. CONCLUSIONS: CT imaging provides valuable assessments of body composition as part of the staging process for several cancer types, saving both time and cost. Gender specific scales and scanner bias adjustments should be carried out to successfully implement SATr measures in clinical practice.


Assuntos
Neoplasias , Humanos , Neoplasias/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Gordura Subcutânea/diagnóstico por imagem , Tecido Adiposo
2.
Annu Int Conf IEEE Eng Med Biol Soc ; 2021: 677-680, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34891383

RESUMO

Post-prandial hypoglycemia occurs 2-5 hours after food intake, in not only insulin-treated patients with diabetes but also other metabolic disorders. For example, postprandial hypoglycemia is an increasingly recognized late metabolic complication of bariatric surgery (also known as PBH), particularly gastric bypass. Underlying mechanisms remain incompletely understood to date. Besides excessive insulin exposure, impaired counter-regulation may be a further pathophysiological feature. To test this hypothesis, we need standardized postprandial hypoglycemic clamp procedures in affected and unaffected individuals allowing to reach identical predefined postprandial hypoglycemic trajectories. Generally, in these experiments, clinical investigators manually adjust glucose infusion rate (GIR) to clamp blood glucose (BG) to a target hypoglycemic value. Nevertheless, reaching the desired target by manual adjustment may be challenging and possible glycemic undershoots when approaching hypoglycemia can be a safety concern for patients. In this study, we developed a PID algorithm to assist clinical investigators in adjusting GIR to reach the predefined trajectory and hypoglycemic target. The algorithm is developed in a manual mode to permit the clinical investigator to interfere. We test the controller in silico by simulating glucose-insulin dynamics in PBH and healthy nonsurgical individuals. Different scenarios are designed to test the robustness of the algorithm to different sources of variability and to errors, e.g. outliers in the BG measurements, sampling delays or missed measurements. The results prove that the PID algorithm is capable of accurately and safely reaching the target BG level, on both healthy and PBH subjects, with a median deviation from reference of 2.8% and 2.4% respectively.Clinical relevance- This control algorithm enables standardized, accurate and safe postprandial hypoglycemic clamps, as evidenced in silico in PBH patients and controls.


Assuntos
Hipoglicemia , Hipoglicemiantes , Algoritmos , Glicemia , Humanos , Hipoglicemia/induzido quimicamente , Hipoglicemiantes/uso terapêutico , Período Pós-Prandial
4.
J Am Chem Soc ; 142(40): 16953-16964, 2020 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-32902974

RESUMO

Pharmacological modulation of cannabinoid type 2 receptor (CB2R) holds promise for the treatment of numerous conditions, including inflammatory diseases, autoimmune disorders, pain, and cancer. Despite the significance of this receptor, researchers lack reliable tools to address questions concerning the expression and complex mechanism of CB2R signaling, especially in cell-type and tissue-dependent contexts. Herein, we report for the first time a versatile ligand platform for the modular design of a collection of highly specific CB2R fluorescent probes, used successfully across applications, species, and cell types. These include flow cytometry of endogenously expressing cells, real-time confocal microscopy of mouse splenocytes and human macrophages, as well as FRET-based kinetic and equilibrium binding assays. High CB2R specificity was demonstrated by competition experiments in living cells expressing CB2R at native levels. The probes were effectively applied to FACS analysis of microglial cells derived from a mouse model relevant to Alzheimer's disease.


Assuntos
Doença de Alzheimer/metabolismo , Corantes Fluorescentes/química , Microglia/metabolismo , Receptor CB2 de Canabinoide/análise , Animais , Células CHO , Cricetulus , Modelos Animais de Doenças , Citometria de Fluxo , Transferência Ressonante de Energia de Fluorescência , Humanos , Ligantes , Camundongos , Simulação de Acoplamento Molecular , Sondas Moleculares/química , Imagem Óptica , Sensibilidade e Especificidade , Transdução de Sinais
5.
Urol Case Rep ; 33: 101284, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32514403

RESUMO

Ketamine related urinary tract complications were first reported in Hong Kong since 2007. The current case report describes a 37 years old male with long history of ketamine abuse, renal impairment, hypertension and HCV hepatitis, presented to us with insidious onset of painful scrotal swelling post bilateral nephrectomy, prostate and seminal vesicle preserving cystectomy. Radiological imaging and intraoperative finding revealed that it was a large spermatocele with urethroscrotal fistula, which was likely due to urethra stricture. The review of literature showed no guidelines for treatment, a symptoms based and multidisciplinary team approach is recommended.

6.
Br J Oral Maxillofac Surg ; 57(6): 582-586, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31178079

RESUMO

Sialolithiasis is one of most common diseases to affect major salivary glands, with a symptomatic incidence of 27 cases per million per annum. The majority form within the submandibular gland where minimally-invasive treatments have all but eliminated adenectomy. All records of patients presenting with submandibular stones between 1997 and 2015 were reviewed. Stones <5mm were retrieved through endoscopic or radiographic techniques, 5-7mm stones were initially considered for extra-corporeal shock wave lithotripsy, but after poor results were treated through intraoral surgical removal with those >7mm. Follow up was performed at 1 week and 3 months with current status performed with postal and telephone questionnaires. 378 patients had 424 stones removed, successful retrieval in 94% (n=356), with 50 having had previous failures. Median number of stones per patient was 1 (range 1-4), with a mean size of 8.6mm (SD 4.5mm) mainly located at the hilum (50.5%), anterior duct (30%) and Genu (17%). 256 patients (65%) treated through intraoral surgical extraction, 92 (24%) endoscopic alone. Inpatient stay was 1.4 days in first third and 0.5 days in final third. Adenectomy occurred in 14 patients, due to failure to retrieve the sialolith or unresolved symptoms. Complications involved 11 patients with permanent paraesthesia, 7 ranulas and 14 strictures. Patients with preoperative strictures were more likely to develop complications (p=0.002) with paraesthesia being most common. Intraoral minimally-invasive surgery is aesthetic, curative and spares the risk to marginal mandibular nerve and submandibular gland. Length of inpatient stay improved and ranula risk reduced throughout the study.


Assuntos
Procedimentos Cirúrgicos Minimamente Invasivos , Cálculos das Glândulas Salivares , Doenças da Glândula Submandibular , Endoscopia , Estética Dentária , Humanos , Cálculos das Glândulas Salivares/cirurgia , Glândula Submandibular , Doenças da Glândula Submandibular/cirurgia
7.
Geriatr Gerontol Int ; 18(5): 745-749, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29336103

RESUMO

AIM: Although much attention has been on integrating the palliative care approach into services of long-term care homes for older people living with frailty and progressive diseases, little is known about the staff preparedness for these new initiatives. The present study aimed to develop and test the psychometric properties of an instrument for measuring care home staff preparedness in providing palliative and end-of-life care. METHODS: A 16-item instrument, covering perceived knowledge, skill and psychological readiness, was developed. A total of 247 staff members of different ranks from four care homes participated in the study. Exploratory factor analysis using the principal component analysis extraction method with varimax rotation was carried out for initial validation. Known group comparison was carried out to examine its discriminant validity. Reliability of the instrument was assessed based on test-retest reliability of a subsample of 20 participants and the Cronbach's alpha of the items. RESULTS: Exploratory factor analysis showed that the instrument yielded a three-factor solution, which cumulatively accounted for 68.5% of the total variance. Three subscales, namely, willingness, capability and resilience, showed high internal consistency and test-retest reliability. It also showed good discriminant validity between staff members of professional and non-professional groups. CONCLUSIONS: This is a brief, valid and reliable scale for measuring care home staff preparedness for providing palliative and end-of-life care. It can be used to identify their concerns and training needs in providing palliative and end-of-life care, and as an outcome measure to evaluate the effects of interventional studies for capacity building in this regard. Geriatr Gerontol Int 2018; 18: 745-749.


Assuntos
Pessoal de Saúde/psicologia , Instituição de Longa Permanência para Idosos , Cuidados Paliativos , Inquéritos e Questionários , Assistência Terminal , Humanos , Assistência de Longa Duração , Psicometria , Reprodutibilidade dos Testes
9.
Acta Biomater ; 51: 351-362, 2017 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-28110069

RESUMO

One of the greatest challenges for the development of genetic therapies is the efficient targeted delivery of therapeutic nucleic acids. Towards this goal, we have introduced a new engineering initiative in self-assembly of biologically safe and stable nanovesicle complexes (∼90 to 140nm) derived from giant unilamellar vesicle (GUV) precursors and comprising plasmid DNA or siRNA and targeting peptide ligands. The biological performance of the engineered nanovesicle complexes were studied both in vitro and in vivo and compared with cationic liposome-based lipopolyplexes. Compared with cationic lipopolyplexes, nanovesicle complexes did not show advantages in transfection and cell uptake. However, nanovesicle complexes neither displayed significant cytotoxicity nor activated the complement system, which are advantageous for intravenous injection and tumour therapy. On intravenous administration into a neuroblastoma xenograft mouse model, nanovesicle complexes were found to distribute throughout the tumour interstitium, thus providing an alternative safer approach for future development of tumour-specific therapeutic nucleic acid interventions. On oropharyngeal instillation, nanovesicle complexes displayed better transfection efficiency than cationic lipopolyplexes. The technological advantages of nanovesicle complexes, originating from GUVs, over traditional cationic liposome-based lipopolyplexes are discussed. STATEMENT OF SIGNIFICANCE: The efficient targeted delivery of nucleic acids in vivo provides some of the greatest challenges to the development of genetic therapies. Giant unilamellar lipid vesicles (GUVs) have been used mainly as cell and tissue mimics and are instrumental in studying lipid bilayers and interactions. Here, the GUVs have been modified into smaller nanovesicles. We have then developed novel nanovesicle complexes comprising self-assembling mixtures of the nanovesicles, plasmid DNA or siRNA, and targeting peptide ligands. Their biophysical properties were studied and their transfection efficiency was investigated. They transfected cells efficiently without any associated cytotoxicity and with targeting specificity, and in vivo they resulted in very high and tumour-specific uptake and in addition, efficiently transfected the lung. The peptide-targeted nanovesicle complexes allow for the specific targeted enhancement of nucleic acid delivery with improved biosafety over liposomal formulations and represent a promising tool to improve our arsenal of safe, non-viral vectors to deliver therapeutic cargos in a variety of disorders.


Assuntos
Técnicas de Transferência de Genes , Nanopartículas/química , Ácidos Nucleicos/química , Peptídeos/química , Lipossomas Unilamelares/química , Administração Intravenosa , Animais , Fenômenos Biofísicos , Western Blotting , Cátions , Linhagem Celular Tumoral , Sobrevivência Celular , Ativação do Complemento , Endocitose , Feminino , Citometria de Fluxo , Humanos , Pulmão/metabolismo , Camundongos Endogâmicos C57BL , RNA Interferente Pequeno/metabolismo , Transfecção , Transgenes
10.
J Mech Behav Biomed Mater ; 66: 58-67, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27838591

RESUMO

A drug-free procedure for killing malignant cells in a cell-type specific manner would represent a significant breakthrough for leukemia treatment. Here, we show that mechanically vibrating a cell in a specific oscillation condition can significantly promote necrosis. Specifically, oscillating the cell by a low-power laser trap at specific frequencies of a few Hz was found to result in increased death rate of 50% or above in different types of myelogenous leukemia cells, while normal leukocytes showed very little response to similar laser manipulations. The alteration of cell membrane permeability and cell volume, detected from ethidium bromide staining and measurement of intracellular sodium ion concentration, together with the observed membrane blebbing within 10min, suggest cell necrosis. Mechanics modelling reveals severe distortion of the cytoskeleton cortex at frequencies in the same range for peaked cell death. The disruption of cell membrane leading to cell death is therefore due to the cortex distortion, and the frequency at which this becomes significant is cell-type specific. Our findings lay down a new concept for treating leukemia based on vibration induced disruption of membrane in targeted malignant cells.


Assuntos
Morte Celular , Núcleo Celular/patologia , Citoesqueleto/patologia , Pinças Ópticas , Vibração , Apoptose , Linhagem Celular Tumoral , Permeabilidade da Membrana Celular , Tamanho Celular , Citoplasma , Humanos , Leucemia Mieloide
11.
Int J Oral Maxillofac Surg ; 46(2): 198-203, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27658755

RESUMO

Two different surgical methods for the treatment of unilateral traumatic temporomandibular joint (TMJ) ankylosis with a medially displaced residual condyle are described. Eighteen patients with unilateral traumatic TMJ ankylosis and a medially displaced residual condyle, treated between 2008 and 2013, were included in this study. Group A patients (n=10) were treated with an autogenous coronoid process graft (ACPG) for reconstruction of the mandibular condyle, while group B patients (n=8) were treated by lateral arthroplasty (LAP); a temporalis myofascial flap (TMF) was used as interpositional material in both groups. The long-term results of the two treatments were compared through postoperative computed tomography and clinical follow-up examinations. The two groups were compared in terms of the recurrence rate, facial pattern change, and improvement in maximum inter-incisal opening (MIO) using SPSS 18.0 software. All patients were followed up for 12-24 months. Two patients in group A (20%) had reankylosis; no reankylosis was observed in group B patients. Compared with the ACPG, LAP improved the facial pattern and MIO significantly (P<0.05). LAP is a feasible and effective surgical method for the treatment of unilateral traumatic TMJ ankylosis when the displaced residual condyle is bigger than one third of the condylar head.


Assuntos
Anquilose/cirurgia , Artroplastia/métodos , Transplante Ósseo/métodos , Procedimentos de Cirurgia Plástica/métodos , Transtornos da Articulação Temporomandibular/cirurgia , Adolescente , Adulto , Criança , Feminino , Humanos , Masculino , Recidiva , Retalhos Cirúrgicos , Resultado do Tratamento
12.
Sci Rep ; 6: 22824, 2016 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-26956215

RESUMO

Suspended cells are difficult to be transfected by common biochemical methods which require cell attachment to a substrate. Mechanical oscillations of suspended cells at certain frequencies are found to result in significant increase in membrane permeability and potency for delivery of nano-particles and genetic materials into the cells. Nanomaterials including siRNAs are found to penetrate into suspended cells after subjecting to short-time mechanical oscillations, which would otherwise not affect the viability of the cells. Theoretical analysis indicates significant deformation of the actin-filament network in the cytoskeleton cortex during mechanical oscillations at the experimental frequency, which is likely to rupture the soft phospholipid bilayer leading to increased membrane permeability. The results here indicate a new method for enhancing cell transfection.


Assuntos
Estresse Mecânico , Transfecção/métodos , Transformação Genética , Linhagem Celular Tumoral , Membrana Celular/fisiologia , Endocitose , Genes , Humanos , Nanoestruturas , Permeabilidade
13.
J Dairy Sci ; 99(2): 1019-1028, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26627860

RESUMO

This study evaluated the antimicrobial activity of tea polyphenols (TP) against 4 Cronobacter sakazakii strains with different sequence types (ST) isolated from powdered infant formula (PIF). The results showed that in normal saline, 5mg/mL of TP (pH 3.44) could eliminate approximately 7.0 log cfu/mL of C. sakazakii within 1 h; in rehydrated PIF, after acidification with HCl (pH 3.55), TP showed a stronger antibacterial activity compared with the controls (malic acid, ascorbic acid, and citric acid). Further, some differences were obvious in tolerance to TP between C. sakazakii strains with different ST. The tolerance of C. sakazakii CE1 (ST4) to TP was found to be greater than that of the other 3 C. sakazakii strains (ST1, ST8, and ST64). The results of recovered test and transmission electron microscope analysis revealed that the action of TP against C. sakazakii was an irreversible bactericidal process caused by leakage of cytoplasm. Taken together, these results indicated that TP had an effective bactericidal effect against C. sakazakii, and provided a new idea for preventing and inactivating C. sakazakii in PIF.


Assuntos
Antibacterianos/farmacologia , Camellia sinensis/química , Cronobacter sakazakii/efeitos dos fármacos , Cronobacter sakazakii/isolamento & purificação , Fórmulas Infantis/microbiologia , Polifenóis/farmacologia , Animais , Ácido Cítrico , Microbiologia de Alimentos , Humanos , Lactente , Polifenóis/química
14.
Artigo em Chinês | MEDLINE | ID: mdl-29871063

RESUMO

Objective:To observe the effect of NGF on the expression of BMP-2 in rabbit model and explore the molecular mechanism of NGF which might promote the healing of mandibular fracture with nerve injury. Method:The 48 New-Zealand white rabbits were randomly divided into the experimental group (mandibular fracture+to cut off the nerve bundle+NGF by GS), the control group (mandibular fracture+to cut off the nerve bundle+NS by GS), the blank group (mandibular fracture+to cut off the nerve bundle) and the full-set group (mandibular fracture+retains the nerve bundle). After 2 weeks, 4 weeks, 6 weeks and 8 weeks, 3 rabbits were sacrificed in each group for HE staining and RT-PCR, respectively. Result:HE staining showed the osteogenesis phenomenon: the experimental group was clearer than control group, the full-set group was clearer than the blank group and the control group is similarly to the blank group. RT-PCR results revealed that there was a statistically significance in the early stage. The expression of BMP-2 peaked in 2 weeks and decreased later with time. Conclusion:The local application of NGF can prompt BMP-2 expression in the early stages of the mandibular fracture with partial nerve injury healing and this may be one of the molecular mechanisms.


Assuntos
Proteína Morfogenética Óssea 2/metabolismo , Consolidação da Fratura , Fraturas Mandibulares/metabolismo , Fator de Crescimento Neural/fisiologia , Animais , Osteogênese , Coelhos , Cicatrização
15.
Hong Kong Med J ; 20(1): 37-44, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23878200

RESUMO

OBJECTIVES. To investigate use of the R.E.N.A.L. nephrometry score in relation to the choice of treatment and postoperative complications for renal masses. DESIGN. Case series. SETTING. A tertiary referral hospital in Hong Kong. PATIENTS. Data of patients undergoing nephrectomy were collected retrospectively from a clinical database and analysed. A R.E.N.A.L. nephrometry score was allocated to each renal tumour by a blinded qualified radiologist, utilising computerised imaging systems. Patient demographics, choice of surgery (radical vs partial), and approaches (open vs minimally invasive) were analysed with respect to their R.E.N.A.L. score. RESULTS. In all, 74 patients were included during the study period, of which 38 underwent partial nephrectomy and 36 underwent radical nephrectomy. No differences between the groups were found with respect to patient demographics. There were significant differences between the partial and radical nephrectomy groups in terms of their mean nephrometry score (6.9 vs 9.3, P<0.001). The mean nephrometry sum was also significantly different in the open approach versus the minimally invasive approach in patients having partial nephrectomy (7.8 vs 6.0, P=0.001). There was no difference in the postoperative 90-day morbidity and mortality in the partial nephrectomy and radical nephrectomy groups. CONCLUSIONS. The R.E.N.A.L. nephrometry score of a renal mass correlated significantly with our choice of surgery (partial vs radical) and our approach to surgery (open vs minimally invasive surgery), particularly in the partial nephrectomy group. It does not, however, correlate with postoperative complications. The nephrometry score provides a useful tool for objectively describing renal mass characteristics and enhancing better communication for the operative planning directed at renal masses.


Assuntos
Carcinoma de Células Renais/patologia , Carcinoma de Células Renais/cirurgia , Neoplasias Renais/patologia , Neoplasias Renais/cirurgia , Nefrectomia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Complicações Pós-Operatórias , Estudos Retrospectivos
16.
Oncogene ; 33(34): 4316-29, 2014 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-24362530

RESUMO

The forkhead box transcription factor FOXM1 is an essential effector of G2/M-phase transition, mitosis and the DNA damage response. As such, it is frequently deregulated during tumorigenesis. Here we report that FOXM1 is dynamically modified by SUMO1 but not by SUMO2/3 at multiple sites. We show that FOXM1 SUMOylation is enhanced in MCF-7 breast cancer cells in response to treatment with epirubicin and mitotic inhibitors. Mutation of five consensus conjugation motifs yielded a SUMOylation-deficient mutant FOXM1. Conversely, fusion of the E2 ligase Ubc9 to FOXM1 generated an auto-SUMOylating mutant (FOXM1-Ubc9). Analysis of wild-type FOXM1 and mutants revealed that SUMOylation inhibits FOXM1 activity, promotes translocation to the cytoplasm and enhances APC/Cdh1-mediated ubiquitination and degradation. Further, expression of the SUMOylation-deficient mutant enhanced cell proliferation compared with wild-type FOXM1, whereas the FOXM1-Ubc9 fusion protein resulted in persistent cyclin B1 expression and slowed the time from mitotic entry to exit. In summary, our findings suggest that SUMOylation attenuates FOXM1 activity and causes mitotic delay in cytotoxic drug response.


Assuntos
Fatores de Transcrição Forkhead/metabolismo , Mitose , Proteína SUMO-1/metabolismo , Sumoilação , Antibióticos Antineoplásicos/farmacologia , Antígenos CD , Sítios de Ligação , Caderinas/metabolismo , Proliferação de Células/efeitos dos fármacos , Citoplasma/metabolismo , Resistencia a Medicamentos Antineoplásicos , Epirubicina/farmacologia , Proteína Forkhead Box M1 , Pontos de Checagem da Fase G2 do Ciclo Celular , Células HeLa , Humanos , Células MCF-7 , Nocodazol/farmacologia , Transporte Proteico , Proteólise
17.
Cytometry A ; 83(6): 540-51, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23504822

RESUMO

We present measurements by deep-ultraviolet mass mapping of nucleic acid (NA) and protein for five commonly cultured and three primary cell types. The dry mass distribution at submicron resolution was determined on a single-cell basis for 250-500 cells from each of these types. Since the method carries a direct reference to a spectrophotometric standard (molar extinction coefficient), we are able to calibrate the absolute weight distributions both on a cell-to-cell basis within each type and across types. We also provide a calibration in absolute mass units for fluorescence-based measurements (flow cytometry and fluorescence microscopy). As might be expected the cultured cell lines show a high concentration of nucleic acids in the nuclear compartment, much larger than the genomic 2C number even in the G1 stage. The whole-cell nucleic-acid/protein ratio was found to be a characteristic of cell lines that persists independent of cell cycle and, as a result, this ratio has some value for phenotyping. Primary chicken red blood cells (cRBC), often used as a cytometry standard, were determined to have a nuclear-isolated nucleic acid content much closer to the genomic number than the cultured cell lines (cRBC: 3.00 pg total NA, 2.30 pg DNA, and 0.70 pg RNA). The individual blastomeres (n = 54) from mouse embryos at eight-cell stage were measured and found to vary by more than a factor or two in total protein and nucleic acid content (0.8-2.3 ng total protein, 70-150 pg total NA). The ratio of nucleic acid to protein was more nearly constant for each blastomere from a particular embryo and this ratio was found to be an identifying characteristic that varies from embryo to embryo obtained from a single flushing of a mouse.


Assuntos
DNA/análise , Proteínas/análise , RNA/análise , Animais , Blastômeros/química , Blastômeros/citologia , Células CHO , Calibragem , Linhagem Celular Tumoral , Galinhas , Cricetulus , Embrião de Mamíferos/química , Embrião de Mamíferos/citologia , Eritrócitos/química , Eritrócitos/citologia , Citometria de Fluxo , Humanos , Camundongos , Microscopia de Fluorescência , Células NIH 3T3 , Análise de Célula Única
18.
Int J Oral Maxillofac Surg ; 42(2): 240-8, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22763137

RESUMO

This study investigated the effects of in vitro chondrogenic differentiated mesenchymal stem cells (MSCs) on cartilage and subchondral cancellous bone in temporomandibular joint osteoarthritis (TMJOA). Four weeks after induction of osteoarthritis (OA), the joints received hylartin solution, non-chondrogenic MSCs or in vitro chondrogenic differentiated MSCs. The changes in cartilage and subchondral cancellous bone were evaluated by histology, reverse transcription polymerase chain reaction and micro-computed tomography (CT). Implanted cells were tracked using Adeno-LacZ labelling. The differentiated MSC-treated group had better histology than the MSC-treated group at 4 and 12 weeks, but no difference at 24 weeks. Increased mRNA expression of collegan II, aggeran, Sox9 and decreased matrix metalloproteinase 13 (MMP13) were observed in differentiated MSC-treated groups compared to the undifferentiated MSC-treated group at 4 weeks. The differentiated MSC-treated group had decreased bone volume fraction, trabecular thickness and bone surface density, and increased trabecular spacing in the subchondral cancellous bone than the undifferentiated MSC-treated group. Transplanted cells were observed at cartilage, subchondral bone, and the synovial membrane lining at 4 weeks. Intra-articular injection of MSCs could delay the progression of TMJOA, and in vitro chondrogenic induction of MSCs could enhance the therapeutic effects. This provides new insights into the role of MSCs in cell-based therapies for TMJOA.


Assuntos
Regeneração Óssea , Condrogênese , Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais/citologia , Osteoartrite/terapia , Transtornos da Articulação Temporomandibular/terapia , Agrecanas/biossíntese , Agrecanas/genética , Animais , Densidade Óssea , Cartilagem Articular , Diferenciação Celular , Células Cultivadas , Condrócitos/citologia , Colágeno Tipo II/biossíntese , Colágeno Tipo II/genética , Gliceraldeído 3-Fosfato Desidrogenase (NADP+)/biossíntese , Gliceraldeído 3-Fosfato Desidrogenase (NADP+)/genética , Injeções Intra-Articulares , Metaloproteinase 13 da Matriz/biossíntese , Metaloproteinase 13 da Matriz/genética , Osteoartrite/diagnóstico por imagem , Coelhos , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Transcrição SOX9/biossíntese , Fatores de Transcrição SOX9/genética , Transtornos da Articulação Temporomandibular/diagnóstico por imagem , Microtomografia por Raio-X
19.
Leukemia ; 27(2): 260-8, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22797419

RESUMO

Internal tandem duplication (ITD) of the fms-like tyrosine kinase 3 (FLT3) gene is a gain-of-function mutation common in acute myeloid leukaemia (AML). It is associated with inferior prognosis and response to chemotherapy. Single base mutations at the FLT3 tyrosine kinase domain (TKD) also leads to a gain of function, although its prognostic significance is less well defined because of its rarity. The clinical benefits of FLT3 inhibition are generally limited to AML with FLT3-ITD. However, responses are transient and leukaemia progression invariably occurs. There is compelling evidence that leukaemia clones carrying both ITD and TKD mutations appear when resistance to FLT3 inhibitors occurs. Interestingly, the emergence of double ITD and TKD mutants can be recapitulated in vitro when FLT3-ITD+ leukaemia cell lines are treated with mutagens and FLT3 inhibitors. Furthermore, murine xenotransplantation models also suggest that, in some cases, the FTL3-ITD and TKD double mutants actually exist in minute amounts before treatment with FLT3 inhibitors, expand under the selection pressure of FLT3 inhibition and become the predominant resistant clone(s) during the drug-refractory phase. On the basis of this model of clonal evolution, a multipronged strategy using more potent FLT3 inhibitors, and a combinatorial approach targeting both FLT3-dependent and FLT3-independent pathways, will be needed to improve outcome.


Assuntos
Antineoplásicos/uso terapêutico , Leucemia Mieloide Aguda/tratamento farmacológico , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidores , Animais , Humanos , Leucemia Mieloide Aguda/enzimologia
20.
Oncogene ; 32(39): 4634-45, 2013 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-23108394

RESUMO

FOXM1 is implicated in genotoxic drug resistance but its role and mechanism of action remain unclear. Here, we establish that γH2AX foci, indicative of DNA double-strand breaks (DSBs), accumulate in a time-dependent manner in the drug-sensitive MCF-7 cells but not in the resistant counterparts in response to epirubicin. We find that FOXM1 expression is associated with epirubicin sensitivity and DSB repair. Ectopic expression of FOXM1 can increase cell viability and abrogate DSBs sustained by MCF-7 cells following epirubicin, owing to an enhancement in repair efficiency. Conversely, alkaline comet and γH2AX foci formation assays show that Foxm1-null cells are hypersensitive to DNA damage, epirubicin and γ-irradiation. Furthermore, we find that FOXM1 is required for DNA repair by homologous recombination (HR) but not non-homologous end joining (NHEJ), using HeLa cell lines harbouring an integrated direct repeat green fluorescent protein reporter for DSB repair. We also identify BRIP1 as a direct transcription target of FOXM1 by promoter analysis and chromatin-immunoprecipitation assay. In agreement, depletion of FOXM1 expression by small interfering RNA downregulates BRIP1 expression at the protein and mRNA levels in MCF-7 and the epirubicin-resistant MCF-7 Epi(R) cells. Remarkably, the requirement for FOXM1 for DSB repair can be circumvented by reintroduction of BRIP1, suggesting that BRIP1 is an important target of FOXM1 in DSB repair. Indeed, like FOXM1, BRIP1 is needed for HR. These data suggest that FOXM1 regulates BRIP1 expression to modulate epirubicin-induced DNA damage repair and drug resistance.


Assuntos
Antibióticos Antineoplásicos/farmacologia , Quebras de DNA de Cadeia Dupla , Proteínas de Ligação a DNA/fisiologia , Resistencia a Medicamentos Antineoplásicos/fisiologia , Epirubicina/farmacologia , Fatores de Transcrição Forkhead/fisiologia , Proteínas de Neoplasias/fisiologia , RNA Helicases/fisiologia , Reparo de DNA por Recombinação/fisiologia , Animais , Dano ao DNA , DNA de Neoplasias/efeitos dos fármacos , DNA de Neoplasias/genética , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/genética , Proteínas de Grupos de Complementação da Anemia de Fanconi , Feminino , Fibroblastos , Proteína Forkhead Box M1 , Fatores de Transcrição Forkhead/antagonistas & inibidores , Raios gama , Histonas/análise , Humanos , Células MCF-7/efeitos dos fármacos , Células MCF-7/metabolismo , Células MCF-7/efeitos da radiação , Camundongos , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , RNA Helicases/biossíntese , RNA Helicases/genética , Interferência de RNA , RNA Mensageiro/biossíntese , RNA Neoplásico/biossíntese , RNA Interferente Pequeno/farmacologia , Tolerância a Radiação , Proteínas Recombinantes de Fusão/fisiologia
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