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1.
Nutr Cancer ; 74(8): 2937-2945, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35225108

RESUMO

Malnutrition among colorectal cancer patients can impair quality of life and decrease survival. This study evaluated the nutritional status of colorectal cancer patients and its association with quality of life among Filipino colorectal cancer patients seen in a tertiary hospital. A cross-sectional study was conducted among colorectal cancer patients seen at the Philippine General Hospital between December 1, 2019 and February 28, 2020. Nutritional status was evaluated using the Subjective Global Assessment, while quality of life was assessed using the EORTC QLQ-C30. Descriptive statistics, ANOVA and logistic regression were employed for analysis. Among 292 patients, malnutrition was noted in 76.4%. Stage III cancer had a higher odds for malnutrition (OR (odds ratio) = 6.22, 95% confidence interval (CI): 1.59, 24.42). Patients who received or were currently receiving chemotherapy were less likely to develop malnutrition (OR = 0.35, 95% CI: 0.18-0.69). Global health status and all functional subscale scores for the severely malnourished group were lower while the scores for symptom scales increased with the degree of malnutrition. There was a high prevalence of malnutrition among colorectal cancer patients and this was associated with poor quality of life. Future directions emphasizing early nutritional screening and assessment are recommended.


Assuntos
Desnutrição , Neoplasias , Estudos Transversais , Humanos , Desnutrição/diagnóstico , Desnutrição/epidemiologia , Desnutrição/etiologia , Neoplasias/epidemiologia , Avaliação Nutricional , Estado Nutricional , Qualidade de Vida , Inquéritos e Questionários , Centros de Atenção Terciária
2.
Curr Probl Cancer ; 45(6): 100713, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-33589275

RESUMO

INTRODUCTION: Central nervous system (CNS) metastasis from nasopharyngeal carcinoma (NPC) is rare and presents with high morbidity and mortality. As a rare entity, a few patients with CNS metastasis from NPC have been reported, and no studies were available on treatment and prognosis. Based on our clinical experience, early diagnosis with incorporation of a clear palliative plan is imperative in providing holistic care for patients with locally-invasive and metastatic nasopharyngeal carcinoma. CASE REPORT: Our study reports a case of a 48-year-old Filipino male with known NPC Stage IVB who developed acute symptoms of constipation, urinary retention, and bilateral lower limb weakness and numbness. Magnetic resonance imaging showed intramedullary lesions in multiple segments of the spinal cord. Steroid and radiotherapy of the spine were initiated with noted transient improvement of the motor strength. Subsequently, he developed cancer-related stroke. The patient progressively deteriorated despite best medical care.


Assuntos
Carcinoma de Células Escamosas/patologia , Carcinoma Nasofaríngeo/patologia , Neoplasias Nasofaríngeas/patologia , Neoplasias da Medula Espinal/secundário , Humanos , Masculino , Pessoa de Meia-Idade , Filipinas , Neoplasias da Medula Espinal/terapia , Resultado do Tratamento
3.
J Med Cases ; 11(10): 309-316, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34434336

RESUMO

Follicular dendritic cell sarcoma (FDCS) accounts for < 0.4% of soft tissue sarcomas. Only 35 cases of tonsillar FDCS have been reported, and majority had localized presentation. We present a case of FDCS of the tonsil, wherein a well-coordinated trimodality approach provided good disease control in advanced disease. A 53-year-old man presented with a painless and enlarging neck mass of 11-month duration, with no other symptoms. Close examination revealed a 10 × 5 cm mass at the left carotid triangle, and a 3.2 × 2.2 cm mass at the left tonsillar fossa. Imaging revealed the tumor to be unresectable due to its attachment to the great vessels. There were no distant metastases. Biopsy and immunohistochemistry were initially deemed consistent with an undifferentiated sarcoma. Palliative chemotherapy was given using single agent doxorubicin and subsequent dacarbazine, resulting in partial response and stable disease, respectively. Pathological re-evaluation was pursued because of the uncharacteristic slow progression of the tumor, revealing diffuse positivity for CD21 and negative for CD1A and CD34, consistent with FDCS. The patient underwent three cycles of gemcitabine plus docetaxel resulting in 50% regression. This allowed dissection of level IB-V lymph nodes and subsequent radiotherapy for the neck and tonsillar mass, with weekly gemcitabine as a radiosensitizer. Evaluation 8 months post-treatment showed no signs of disease progression. Treatment-related complications included radiation dermatitis and swallowing dysfunction, which both resolved on follow-up. This case highlights the multidisciplinary management of a rare type of sarcoma in an uncommon anatomic location. Precise pathologic diagnosis is important in soft tissue sarcoma because of its therapeutic implications. For FDCS, effective response may still be achieved in the third-line setting.

4.
Acta Medica Philippina ; : 17-23, 2018.
Artigo em Inglês | WPRIM (Pacífico Ocidental) | ID: wpr-959709

RESUMO

@#<p style="text-align: justify;"><strong>BACKGROUND:</strong> While hand hygiene is recognized as the cornerstone for reducing risk for nosocomial infections, compliance in our institution remains low. Previously identified barriers include poor access to hand hygiene products, lack of reminders, and poor knowledge on indications.</p><p style="text-align: justify;"><strong>METHODS:</strong> At the medical wards and ICU of a tertiary hospital, a group of medical students, residents, and nurses was exposed to interventions addressing the identified barriers. Alcohol handrub was provided at each bedside, visual reminders were placed at critical locations, and commonly missed opportunities were reinforced at the start of the study. Hand hygiene compliance was covertly evaluated after two weeks and compared against that of an unexposed group.</p><p style="text-align: justify;"><strong>RESULTS:</strong> 664 and 727 hand hygiene opportunities were observed in the unexposed and exposed groups, respectively. Compliance was higher in the exposed group (32.60% vs. 16.26%, p <0.05), which by subset analysis was consistent for the different healthcare worker designations and locations evaluated. Nurses had the highest compliance rate in both groups.</p><p style="text-align: justify;"><strong>CONCLUSIONS:</strong> These results suggest the efficacy of the employed interventions in improving hand hygiene compliance in this setting. Hand hygiene opportunities identified to be most frequently missed in this observation can guide future intervention efforts in our institution.</p>


Assuntos
Humanos , Higiene das Mãos , Controle de Infecções
5.
Am J Emerg Med ; 35(8): 1043-1048, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28238537

RESUMO

BACKGROUND: Bystanders play a vital role in public access defibrillation (PAD) in out-of-hospital cardiac arrest (OHCA). Dual dispatch of first responders (FR) alongside emergency medical services (EMS) can reduce time to first defibrillation. The aim of this study was to describe the use of automated external defibrillators (AEDs) in OHCAs before EMS arrival. METHODS: All OHCA cases with a shockable rhythm in which an AED was used prior to the arrival of EMS between 2008 and 2015 in western Sweden were eligible for inclusion. Data from the Swedish Register for Cardiopulmonary Resuscitation (SRCR) were used for analysis, on-site bystander and FR defibrillation were compared with EMS defibrillation in the final analysis. RESULTS: Of the reported 6675 cases, 24% suffered ventricular fibrillation (VF), 162 patients (15%) of all VF cases were defibrillated before EMS arrival, 46% with a public AED on site. The proportion of cases defibrillated before EMS arrival increased from 5% in 2008 to 20% in 2015 (p<0.001). During this period, 30-day survival increased in patients with VF from 22% to 28% (p=0.04) and was highest when an AED was used on site (68%), with a median delay of 6.5min from collapse to defibrillation. Adjusted odds ratio for on-site defibrillation versus dispatched defibrillation for 30-day survival was 2.45 (95% CI: 1.02-5.95). CONCLUSIONS: The use of AEDs before the arrival of EMS increased over time. This was associated with an increased 30-day survival among patients with VF. Thirty-day survival was highest when an AED was used on site before EMS arrival.


Assuntos
Reanimação Cardiopulmonar , Desfibriladores , Serviços Médicos de Emergência , Parada Cardíaca Extra-Hospitalar/terapia , Fibrilação Ventricular/terapia , Idoso , Reanimação Cardiopulmonar/métodos , Desfibriladores/estatística & dados numéricos , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Razão de Chances , Parada Cardíaca Extra-Hospitalar/mortalidade , Taxa de Sobrevida/tendências , Suécia/epidemiologia , Fibrilação Ventricular/mortalidade
6.
Artigo em Inglês | WPRIM (Pacífico Ocidental) | ID: wpr-960144

RESUMO

@#<p style="text-align: justify;"><strong>INTRODUCTION:</strong> Contrast-induced nephropathy (CIN) is a serious but preventable complication of coronary procedures. Trimetazidine (TMZ) has recently been explored for use in preventing post-procedural CIN due to its cellular anti-ischemic and antioxidant properties. The objective is to assess the efficacy of oral TMZ in the prevention of contrast induced nephropathy during elective coronary angiography and PCI among patients with renal impairment.</p><p style="text-align: justify;"><strong>METHODS:</strong> We conducted a systematic search of the Cochrane Central Register of Controlled Trials, Pubmed/ MEDLINE, EMBASE, clinicaltrials.gov for articles published until June 2016 for randomized controlled trials examining the effects of adding oral TMZ to standard therapy in preventing CIN. Outcome measures were incidence of CIN, defined as a 0.5 mg/dl or ?25% increase in serum creatinine 48-72 hours after contrast exposure, and incidence of dialysisrequiring CIN. Validity of studies was assessed through a risk assessment tool available from Cochrane. Treatment effect was estimated by calculating the Mantel-Haenszelweighted risk ratio (RR) using a fixed-effects model available from RevMan 5.3.</p><p style="text-align: justify;"><strong>RESULTS:</strong> A total of four studies comprising 714 patients (TMZ group=352, Control group=362) were included in the final analysis. Pooled results revealed the TMZ group was associated with significantly fewer incidences of CIN compared to control (RR 0.33, 95% confidence interval [CI], 0.20, 0.53; P<.00001), with a relative risk reduction of 67% and an absolute risk reduction of 11.04% (NNT=nine). No dialysis-requiring CIN was observed in the included studies.</p><p style="text-align: justify;"><strong>CONCLUSION:</strong> The addition of oral TMZ to standard hydration confers a significant benefit in preventing CIN after coronary procedures among patients with mild to moderate renal impairment. We recommend the addition of TMZ to standard prevention strategies. However, a large well-designed trial should be conducted to determine its effect on other outcomes such as prevention of dialysis-requiring CIN and mortality. </p>


Assuntos
Humanos , Trimetazidina , Angiografia Coronária , MEDLINE , Creatinina , PubMed , Medição de Risco , Insuficiência Renal , Testes de Função Renal
7.
Artigo | WPRIM (Pacífico Ocidental) | ID: wpr-960137

RESUMO

INTRODUCTION: Contrast-induced nephropathy (CIN) is a serious but preventable complication of coronary procedures. Trimetazidine (TMZ) has recently been explored for use in preventing post-procedural CIN due to its cellular anti-ischemic and antioxidant properties. The objective is to assess the efficacy of oral TMZ in the prevention of contrast induced nephropathy during elective coronary angiography and PCI among patients with renal impairment.METHODS: We conducted a systematic search of the Cochrane Central Register of Controlled Trials, Pubmed/ MEDLINE, EMBASE, clinicaltrials.gov for articles published until June 2016 for randomized controlled trials examining the effects of adding oral TMZ to standard therapy in preventing CIN. Outcome measures were incidence of CIN, defined as a 0.5 mg/dl or ?25% increase in serum creatinine 48-72 hours after contrast exposure, and incidence of dialysisrequiring CIN. Validity of studies was assessed through a risk assessment tool available from Cochrane. Treatment effect was estimated by calculating the Mantel-Haenszelweighted risk ratio (RR) using a fixed-effects model available from RevMan 5.3.RESULTS: A total of four studies comprising 714 patients (TMZ group=352, Control group=362) were included in the final analysis. Pooled results revealed the TMZ group was associated with significantly fewer incidences of CIN compared to control (RR 0.33, 95% confidence interval [CI], 0.20, 0.53; PCONCLUSION: The addition of oral TMZ to standard hydration confers a significant benefit in preventing CIN after coronary procedures among patients with mild to moderate renal impairment. We recommend the addition of TMZ to standard prevention strategies. However, a large well-designed trial should be conducted to determine its effect on other outcomes such as prevention of dialysis-requiring CIN and mortality. 


Assuntos
Humanos , Trimetazidina , Angiografia Coronária , MEDLINE , Creatinina , PubMed , Medição de Risco , Insuficiência Renal , Testes de Função Renal
8.
Artigo em Inglês | WPRIM (Pacífico Ocidental) | ID: wpr-633755

RESUMO

INTRODUCTION: Contrast-induced nephropathy (CIN) is a serious but preventable complication of coronary procedures. Trimetazidine (TMZ) has recently been explored for use in preventing post-procedural CIN due to its cellular anti-ischemic and antioxidant properties. The objective is to assess the efficacy of oral TMZ in the prevention of contrast induced nephropathy during elective coronary angiography and PCI among patients with renal impairment. METHODS: We conducted a systematic search of the Cochrane Central Register of Controlled Trials, Pubmed/ MEDLINE, EMBASE, clinicaltrials.gov for articles published until June 2016 for randomized controlled trials examining the effects of adding oral TMZ to standard therapy in preventing CIN. Outcome measures were incidence of CIN, defined as a 0.5 mg/dl or ?25% increase in serum creatinine 48-72 hours after contrast exposure, and incidence of dialysisrequiring CIN. Validity of studies was assessed through a risk assessment tool available from Cochrane. Treatment effect was estimated by calculating the Mantel-Haenszelweighted risk ratio (RR) using a fixed-effects model available from RevMan 5.3. RESULTS: A total of four studies comprising 714 patients (TMZ group=352, Control group=362) were included in the final analysis. Pooled results revealed the TMZ group was associated with significantly fewer incidences of CIN compared to control (RR 0.33, 95% confidence interval [CI], 0.20, 0.53; P CONCLUSION: The addition of oral TMZ to standard hydration confers a significant benefit in preventing CIN after coronary procedures among patients with mild to moderate renal impairment. We recommend the addition of TMZ to standard prevention strategies. However, a large well-designed trial should be conducted to determine its effect on other outcomes such as prevention of dialysis-requiring CIN and mortality. 


Assuntos
Humanos , Trimetazidina , Angiografia Coronária , MEDLINE , Creatinina , PubMed , Medição de Risco , Insuficiência Renal , Testes de Função Renal
9.
Artigo em Inglês | MEDLINE | ID: mdl-30613237

RESUMO

Augmented reality (AR) has the potential to create compelling learning experiences. However, there are few research works exploring the design and evaluation of AR for educational settings. In our research, we treat AR as a type of multimedia that is situated in authentic environments and apply multimedia learning theory as a framework for developing our educational applications. We share our experiences in developing a handheld AR system and one specific use case, namely, situated vocabulary learning. Results of our evaluations show that we are able to create AR applications with good system usability. More importantly, our preliminary evaluations show that AR may lead to better retention of words and improve student attention and satisfaction.

10.
IEEE Comput Graph Appl ; 35(5): 66-75, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26416363

RESUMO

Usability evaluations are important to improving handheld augmented reality (HAR) systems. However, no standard questionnaire considers perceptual and ergonomic issues found in HAR. The authors performed a systematic literature review to enumerate these issues. Based on these issues, they created a HAR usability scale that consists of comprehensibility and manipulability scales. These scales measure general system usability, ease of understanding the information presented, and ease of handling the device. The questionnaires' validity and reliability were evaluated in four experiments, and the results show that the questionnaires consistently correlate with other subjective and objective measures of usability. The questionnaires also have good reliability based on the Cronbach's alpha. Researchers and professionals can directly use these questionnaires to evaluate their own HAR applications or modify them with the insights presented in this article.

11.
Electrophoresis ; 22(3): 511-7, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11258763

RESUMO

The capillary electrochromatographic separation performance of hydrophobic amines and a related quaternary ammonium compound on continuous beds based on polymers of acrylamide has been studied. The chromatographic bed is polymerized in situ and the character of the polymers with regard to hydrophobicity and charge has been systematically changed by regulating its content of isopropyl and sulfonate ligands, respectively. The best performance was obtained for columns with a molar ratio of 1:80 for the sulfonate and isopropyl groups, and resulted in efficiencies up to 200000 plates per meter. The effects on retention, resolution and elution order by ionic strength, pH, and content of acetonitrile in the mobile phase have been investigated. The quaternary ammonium compound was always the least retained irrespective of pH. By increasing the pH, a reversal of the migration order between the tertiary and secondary amine was obtained. The results indicate a complex migration/retention mechanism where ion-exchange, adsorption and electrophoretic mobilities play a role. The concentration limit of detection could be lowered from 1.3 microg/mL to 50 pg/mL by using a high content of 2-propanol (96%) in the sample compared to dissolving the analytes in the mobile phase.


Assuntos
Aminas , Amitriptilina/isolamento & purificação , Antidepressivos Tricíclicos/isolamento & purificação , Eletroforese Capilar/métodos , Nortriptilina/isolamento & purificação , Amitriptilina/análogos & derivados , Amitriptilina/química , Antidepressivos Tricíclicos/química , Cromatografia Capilar Eletrocinética Micelar/métodos , Estrutura Molecular , Nortriptilina/química
12.
Exp Neurol ; 164(1): 184-99, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10877929

RESUMO

Long-term attached cultures, prepared from mouse embryonic days 15-17 lateral ganglionic eminence, were grown in a medium including epidermal growth factor and serum, and the survival, differentiation, and migration of cells from either early or late passages were analyzed following transplantation. The cultured cells had the morphology of type I astroglial cells, with the vast majority of the cells immunoreactive for glial fibrillary acidic protein (around 90%), the intermediate filament marker nestin, and also the mouse-specific neural markers M2 and M6. The cultures were kept over 25 passages (7 months). During the first 8 passages, the growth rate gradually declined, but it increased again after passage 9 and thereafter stabilized at values similar to those observed during the initial culture period. After passages 4-6 and 18, cell suspensions were implanted cross-species into the intact or lesioned striatum of adult (passages 4-5 only) or intact striatum of neonatal rats (passages 4-6 or 18). Both early and late passage cells formed M2 (and M6)-positive transplants. In the neonatal recipients, widespread migration was seen from the needle tract throughout most of the striatum, along the internal capsule, and into the globus pallidus. In the adult striatum, the cells remained mostly around the injection tract, or within 0.4-0.6 mm from the graft core. These long-term attached cultures are interesting to compare to nonattached neurosphere cultures, and might also offer a means of propagating relatively pure populations of astroglia-like cells for basic transplantation studies or for use in experimental trials with ex vivo gene transfer.


Assuntos
Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Astrócitos/transplante , Corpo Estriado/metabolismo , Fator de Crescimento Epidérmico/metabolismo , Proteína Glial Fibrilar Ácida/metabolismo , Proteínas do Tecido Nervoso , Animais , Astrócitos/citologia , Transplante de Tecido Encefálico , Movimento Celular , Células Cultivadas , Corpo Estriado/citologia , Corpo Estriado/embriologia , Corpo Estriado/cirurgia , DNA Satélite/metabolismo , Fator de Crescimento Epidérmico/farmacologia , Feminino , Transplante de Tecido Fetal , Globo Pálido/metabolismo , Sobrevivência de Enxerto , Proteínas de Filamentos Intermediários/metabolismo , Camundongos , Nestina , Ratos , Ratos Sprague-Dawley
13.
Anal Chem ; 72(1): 81-7, 2000 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-10655638

RESUMO

The application range of microchips can be extended to any mode of chromatography by filling the narrow channels with continuous polymer beds, exemplified by electrochromatography and ion-exchange chromatography. "Wall effects" are eliminated by anchoring the bed to the wall of the channel, an arrangement which has the additional advantage that no frits to support the bed are required. The design of the equipment is based on a quartz chip with all auxiliary pieces (for example, electrode vessels and fluid transfer fittings) placed in a rack, which permits a flexibility of great importance for automation. The same resolution and van Deemter plots were obtained in experiments performed in fused-silica capillaries and in chips for both low-molecular-weight (alkyl phenones, antidepressants) and high-molecular-weight substances (proteins). A sample of uracil, phenol, and benzyl alcohol was separated by electrochromatography in less than 20 s.


Assuntos
Cromatografia por Troca Iônica/instrumentação , Cromatografia por Troca Iônica/métodos , Quartzo , Cromatografia Líquida de Alta Pressão , Osmose , Polímeros , Pressão
14.
Neuroreport ; 11(18): 3973-7, 2000 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-11192612

RESUMO

A major obstacle in ex vivo gene transfer has been the loss of transgene expression soon after implantation of the grafted transduced cells. Recently, a lentiviral vector system has been developed which has proven to express high levels of transgenes in vivo after direct injection into the tissue. In this study, we have investigated the use of such a vector for ex vivo gene transfer to the brain. A number of neural cell types were found to be permissive to transduction by the lentiviral vector in vitro and a majority of them expressed the transgene after transplantation to the rat brain. Transgene expression was detected up to 8 weeks post-grafting. These findings suggest that recombinant lentiviral vectors may be used for further development of ex vivo gene therapy protocols to the CNS.


Assuntos
Encéfalo/virologia , Técnicas de Transferência de Genes , Vetores Genéticos/genética , Lentivirus/genética , Transgenes/genética , Animais , Transplante de Tecido Encefálico , Diferenciação Celular/genética , Células Cultivadas/citologia , Células Cultivadas/metabolismo , Células Cultivadas/transplante , DNA Recombinante/genética , Regulação Viral da Expressão Gênica/fisiologia , Terapia Genética/tendências , Proteínas de Fluorescência Verde , Humanos , Proteínas Luminescentes/genética , Camundongos , Ratos , Transplante de Células-Tronco , Células-Tronco/citologia , Células-Tronco/metabolismo , Transdução Genética
16.
J Capillary Electrophor ; 5(1-2): 13-26, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-10327365

RESUMO

In packed chromatographic beds, both Eddy diffusion and the relatively long time the analytes stay in the mobile phase until they collide and interact with the ligands attached to the beads (the residence time in the mobile phase) contribute considerably to zone spreading. One should not expect Eddy diffusion to occur in macroscopically homogeneous separation media, such as gels or polymer solutions, and residence time should be shorter, since the pore size of these media is much smaller than the average distance between the beads in a packed bed. Accordingly, these separation media (which can be regarded as homogeneous continuous beds [monoliths]) should theoretically give very high resolution, which has been verified experimentally: Frontal analysis of a neutral marker, acetone, showed that electroendosmosis in a homogeneous gel displaced the boundary without any distortion except that caused by diffusion (the marker was selected not to interact with the gel). All other common disturbing phenomena in chromatography (for instance, Eddy diffusion and nonspecific adsorption) were, accordingly, negligible, indicating that electrochromatography in homogeneous gels may be the ideal chromatographic method. However, to fully utilize these desirable chromatographic properties of homogeneous continuous beds, one has to choose analyte/bed interactions with sufficiently high association-dissociation rate constants (i.e., the residence time of the analytes in the stationary phase must be kept very short), which will be the subject of forthcoming studies. The electrophoretic counterpart of capillary electrochromatography (CEC), electrophoresis of noncharged analytes in a solution of charged polymers, seems to give a somewhat larger zone broadening, probably due to their high viscosity and conductivity, with attendant longer analysis (= diffusional) times compared to gels. Since the mobile phase is propelled through the gels by electroendosmosis, the theoretical and experimental requirements for high electroendosmotic flow in gels, i.e., short analysis times, are discussed. The electroendosmotic velocity v(x) can be estimated by the simple equation v(x) = Vmax (1-e-kappa x) (1/kappa = the thickness of the double layer; Vmax = the plug flow velocity) when the distance from the channel wall, x, << the radius R of the channel (pore). For kappa R > or = 5, the equation obtains with good approximation for all R values. An initially straight zone in a gel pore should be heavily distorted by the electroendosmotic flow, according to this equation (see Figure 1). However, due to rapid diffusion and other leveling effects, the zone is transported as in perfect plug flow, as is shown experimentally. A plot of electroendosmotic mobility obtained by frontal analysis against 1/(1 + square root of mu) can be used to estimate roughly the pore size in a gel and permits quantitative examination of the current theory of electroendosmosis. It is not a trivial problem to synthesize ligand-containing gels with pores large enough to allow a high electroendosmotic flow. Therefore, we have described a universal method: a polymer containing phenylboronate and acrylic acid groups was synthesized and entrapped in a standard agarose gel (for automated runs, replaceable methoxylated agarose should be used). Both of these charged groups serve to generate the electroendosmotic flow required in electrochromatography. This gel was designed to have the dual property of separating compounds that contain vicinal OH groups in the cis-configuration (exemplified by ribonucleosides) by reaction with the boronate groups, and aromatic substances by virtue of the acrylic acid residues (and perhaps also the phenyl groups) in the polymer and the agarose chains. The latter interaction, the so-called aromatic adsorption, has the advantage that it does not require a time-consuming attachment of ligands. (ABSTRACT TRUNCATED)


Assuntos
Cromatografia em Agarose/métodos , Humanos
17.
Anal Chem ; 68(19): 3468-72, 1996 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-21619279

RESUMO

A simple one-step procedure for the preparation of columns for capillary electrochromatography is described. The nonpolar compounds (stearyl or butyl methacrylate) used for the introduction of hydrophobic ligands (C18, C4) are rendered water-soluble in the aqueous monomer mixture used for the synthesis of the matrix by the addition of a surfactant. This solution is sucked into a piece of fused silica tubing, the inner walls of which are activated by methacryl groups. Following polymerization, the continuous bed column is ready for use. Since the bed is attached covalently to the tubing wall, no frit to support the bed is required, which simplifies the preparation of the column. In addition, a frit can easily become clogged and is often a site for the generation of air bubbles. Some new approaches to increase the resolution and shorten the analysis times in electrochromatography are suggested and demonstrated experimentally, such as sharpening the starting zone, employing gradient elution, or adding SDS (below cmc) to the mobile phase. Separation of five polycyclic aromatic hydrocarbons can be achieved in 5 min in a 25-µm-i.d. column.

18.
J Chromatogr A ; 711(1): 217-22, 1995 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-7496492

RESUMO

The human red cell glucose transporter (Glut1) is a transmembrane protein. Monomeric Glut1 was purified by ion-exchange chromatography in the presence of the non-ionic detergent n-dodecyl octaoxyethylene (C12E8). For focusing, the ionic strength of the solution of C12E8-Glut1 complexes with co-purified lipids was lowered by dialysis, the detergent concentration was increased and carrier ampholytes were added. Focusing was done for 5 min at 3000 V in a methyl cellulose-coated glass capillary (50 microns I.D.). The anolyte H3PO4 was then replaced by NaOH for mobilization towards the anode. Absorbance monitoring at 280 nm showed two groups of zones at pH 6 and 8. Similarly, isoelectric focusing in a rotating quartz tube (3 mm I.D.) gave Glut1 zones at pH 5.5 and 8.0. Phosphorus analysis revealed that the Glut1 zone at pH 8 contained more phospholipids than did the other one. The above results together with previously determined and calculated isoelectric points (pI) of Glut1 indicate that the Glut1 at pH 8 is monomeric and that the zone at pH 5.5-6 represents oligomeric materials. The pI 8.0 at 22 degrees C applies for monomeric Glut1 in the absence of urea. The results exemplify that capillary isoelectric focusing of hydrophobic membrane proteins is possible.


Assuntos
Membrana Eritrocítica/química , Focalização Isoelétrica/métodos , Proteínas de Membrana/análise , Proteínas de Transporte de Monossacarídeos/análise , Cromatografia por Troca Iônica , Transportador de Glucose Tipo 1 , Humanos
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