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1.
Int J Antimicrob Agents ; 62(6): 106971, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37716577

RESUMEN

BACKGROUND: There are many reports on gene mutations observed in methicillin-resistant Staphylococcus aureus (MRSA) showing reduced susceptibility to vancomycin. However, there are limited studies on the genetic alterations that contribute to high vancomycin minimum inhibitory concentrations (MICs) in methicillin-susceptible S. aureus (MSSA). This study aimed to compare MSSA strains with high vancomycin MICs with those with low MICs, and to identify specific genetic alterations associated with increased vancomycin MICs. METHODS: In total, 124 MSSA strains were analysed, with 62 having vancomycin MICs of 1-2 mg/L (MS-HV) and the remaining 62 having MICs <1 mg/L (MS-LV) as control. Polymerase chain reaction amplification and sequencing were conducted to identify point mutations and amino acid changes in the vraSR, graRS and walRK operons and rpoB gene. The number of single nucleotide polymorphisms (SNPs) and specific mutations in the indicated gene were compared between the two groups. RESULTS: The MS-HV strains had a significantly higher median number of SNPs in studied genes than the MS-LV strains (5 vs 3; P < 0.0001), with higher frequency of SNPs in the graR and walK genes. The MS-HV strains also displayed a significantly higher prevalence of specific mutations in the graR gene (V135I, I136V and V136I) compared with the MS-LV strains. The odds of having a high vancomycin MIC was 5.54 times higher in strains with a mutation in the graR gene, and 5.32 times higher in strains with a mutation in the walK gene, compared with those without these mutations. CONCLUSIONS: Mutations in the graR and walK genes may contribute to reduced vancomycin susceptibility in MSSA. This study gives key insights into the mechanisms underlying this phenomenon.


Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Humanos , Vancomicina/farmacología , Staphylococcus aureus/genética , Staphylococcus aureus Resistente a Meticilina/genética , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Meticilina , Infecciones Estafilocócicas/tratamiento farmacológico , Mutación , Pruebas de Sensibilidad Microbiana
2.
J Thorac Dis ; 15(4): 2344-2354, 2023 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-37197516

RESUMEN

Background: Codeine has been long used as an antitussive drug in several countries. However, a prescription pattern of codeine, such as dose or treatment duration, has not been reported in detail. Furthermore, there is few scientific evidence on the efficacy and safety. We aimed to examine codeine prescription pattern and explore treatment response in patients with chronic cough in real-world practice. Methods: This was a retrospective cohort analysis of patients with chronic cough who were newly referred to tertiary allergy and asthma clinics between July 2017 and July 2018. Routinely collected electronic healthcare records (EHRs), including medical notes, prescriptions, and outpatient visits, were analyzed. Codeine prescription records were examined for duration, mean daily dose, and 1-year cumulative dose. Codeine responses were evaluated by manual EHR reviews. Results: Among a total of 1,233 newly referred patients with chronic cough, 666 were prescribed codeine for a median [interquartile range (IQR)] of 27.5 days (IQR 14-60 days); the median daily dose was 30 mg/year (IQR 21.6-30 mg/year), and the 1-year cumulative dose was 720 mg/year (IQR 420-1,800 mg/year). About 14.0% of patients were prescribed codeine for >8 weeks; they were older and had a longer cough duration, throat abnormal sensation and less dyspnea than patients prescribed codeine for ≤8 weeks or who did not receive codeine. Codeine prescription and duration was positively associated with the number of other cough-related medications, diagnostic tests, or outpatient visits. Cough status change was noted in 61.3% of codeine-prescribed patients (as 'improved' in 40.1% and 'not improved' in 21.2%), but not documented in 38.7%. Side effects were described in 7.8%. Conclusions: Codeine prescription may be frequent and chronic in real-world practice of patients with chronic cough, despite the lack of robust clinical evidence on the efficacy. High prescription rates suggest unmet clinical needs. Prospective studies are warranted to identify codeine treatment responses and safety, and to build up clinical evidence to guide appropriate use of narcotic antitussives.

3.
Antibiotics (Basel) ; 12(4)2023 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-37107077

RESUMEN

BACKGROUND: Treatment of device-related infections by drug-resistant Staphylococcus aureus can be challenging, and combination therapy has been proposed as a potential solution. We compared the effectiveness of levofloxacin-rifampin and ciprofloxacin-rifampin combinations in killing methicillin-resistant S. aureus (MRSA) using a time-kill assay. METHODS: We randomly selected 15 vancomycin-susceptible S. aureus (VSSA) strains, 3 vancomycin-intermediate S. aureus (VISA) strains, and 12 heterogeneous VISA (hVISA) strains from the Asian Bacterial Bank. Time-kill experiments were performed in duplicate for each isolate. Viable bacterial counts were determined at 0 h, 4 h, 8 h, and 24 h for the ciprofloxacin- and levofloxacin-rifampin combinations at 1× MIC and 0.5× MIC. We compared synergistic and antagonistic interactions between the two combinations. RESULTS: The viable bacterial count significantly decreased after 24 h of exposure to ciprofloxacin-rifampin and levofloxacin-rifampin combinations, with synergy observed more frequently in isolates exposed to ciprofloxacin-rifampin (43.3%) than levofloxacin-rifampin (20.0%) (p = 0.0082). The synergistic interactions of both combinations were more frequently observed in resistant strains with high MICs of ciprofloxacin (≥16 mg/L) and levofloxacin (≥8 mg/L). Levofloxacin tended to exhibit more frequent antagonistic interactions with rifampin than ciprofloxacin, although there was no statistical difference in antagonism between the two combinations. CONCLUSIONS: Our study demonstrated that ciprofloxacin exhibits superior synergistic activity against MRSA strains, including VISA/hVISA, when combined with rifampin compared with levofloxacin. High MICs of fluoroquinolones were found to predict synergism. Our results suggest that ciprofloxacin may be a more effective choice than levofloxacin for combination therapy with rifampin in the treatment of MRSA infections.

4.
Allergy Asthma Immunol Res ; 15(3): 395-405, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-37075801

RESUMEN

Cough is one of the most common symptoms of acute coronavirus disease 2019, but cough may persist for weeks or months. This study aimed to examine the clinical characteristics of patients with post-coronavirus disease (COVID) persistent cough in the Omicron era. We conducted a pooled analysis comparing 3 different groups: 1) a prospective cohort of post-COVID cough (> 3 weeks; n = 55), 2) a retrospective cohort of post-COVID cough (> 3 weeks; n = 66), and 3) a prospective cohort of non-COVID chronic cough (CC) (> 8 weeks; n = 100). Cough and health status was assessed using patient-reported outcomes (PROs). Outcomes, including PROs and systemic symptoms, were longitudinally evaluated in the prospective post-COVID cough registry participants receiving usual care. A total of 121 patients with post-COVID cough and 100 with non-COVID CC were studied. Baseline cough-specific PRO scores did not significantly differ between post-COVID cough and non-COVID CC groups. There were no significant differences in chest imaging abnormality or lung function between groups. However, the proportions of patients with fractional exhaled nitric oxide (FeNO) ≥ 25 ppb were 44.7% in those with post-COVID cough and 22.7% in those with non-COVID CC, which were significantly different. In longitudinal assessment of the post-COVID registry (n = 43), cough-specific PROs, such as cough severity or Leicester Cough Questionnaire (LCQ) scores, significantly improved between visits 1 and 2 (visit interval: median 35 [interquartile range, IQR: 23-58] days). In the LCQ score, 83.3% of the patients showed improvement (change ≥ +1.3), but 7.1% had worsened (≤ -1.3). The number of systemic symptoms was median 4 (IQR: 2-7) at visit 1 but decreased to median 2 (IQR: 0-4) at visit 2. In summary, post-COVID persistent cough was similar in overall clinical characteristics to CC. Current cough guideline-based approaches may be effective in most patients with post-COVID cough. Measurement of FeNO levels may also be useful for cough management.

5.
Antimicrob Resist Infect Control ; 11(1): 101, 2022 08 05.
Artículo en Inglés | MEDLINE | ID: mdl-35932086

RESUMEN

BACKGROUND: We investigated the trend change in vancomycin-intermediate Staphylococcus aureus (VISA)/heterogeneous VISA (hVISA) prevalence among methicillin-resistant S. aureus (MRSA) bacteremia strains and antistaphylococcal antibiotic use together with mutation studies of vancomycin resistance-related gene loci to evaluate the impact of changes in antibiotic use after new antistaphylococcal antibiotics became available. METHODS: Among 850 healthcare-associated MRSA isolates from 2006 to 2019 at a tertiary hospital in South Korea, hVISA/VISA was determined by modified PAP/AUC analysis, and the identified hVISA/VISA strains were genotyped. Gene mutations at vraSR, graSR, walKR, and rpoB were studied by full-length sequencing. Antistaphylococcal antibiotic use in 2005-2018 was analyzed. RESULTS: Two VISA and 23 hVISA strains were identified. The prevalence rate ratio of hVISA/VISA carrying mutations at the two-component regulatory systems among MRSA was 0.668 (95% CI 0.531-0.841; P = 0.001), and the prevalence rate ratio of hVISA/VISA carrying rpoB gene mutations was 1.293 (95% CI 0.981-1.702; 174 P = 0.068). Annual vancomycin use density analyzed by days of therapy (DOT) per 1,000 patient-days did not decrease significantly, however the annual average length of time analyzed by the number of days vancomycin was administered for each case showed a significantly decreasing trend. CONCLUSIONS: During the 14-year period when the average length of vancomycin therapy decreased every year with the availability of alternative antibiotics, the prevalence of hVISA/VISA did not decrease significantly. This seems to be because the resistant strains carrying the rpoB mutations increased despite the decrease in the strains carrying the mutations at the two-component regulatory systems.


Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Humanos , Staphylococcus aureus Resistente a Meticilina/genética , Pruebas de Sensibilidad Microbiana , Prevalencia , Estudios Retrospectivos , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/epidemiología , Staphylococcus aureus/genética , Vancomicina/farmacología , Vancomicina/uso terapéutico
6.
Asia Pac Allergy ; 12(2): e19, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35571551

RESUMEN

Long coronavirus disease (COVID) refers to an array of variable and fluctuating symptoms experienced after acute illness, with signs and symptoms that persist for 8-12 weeks and are not otherwise explicable. Cough is the most common symptom of acute COVID-19, but cough may persist in some individuals for weeks or months after recovery from acute phase. Long-COVID cough patients may get stigmatised because of the public fear of contagion and reinfection. However, clinical characteristics and longitudinal course of long-COVID cough have not been reported in detail, and evidence-based treatment is also lacking. In this paper, we describe a case of long-COVID severe refractory cough with features of laryngeal hypersensitivity and dysfunction. We characterized cough using patient-reported outcomes and engaged in continuous cough frequency monitoring. Through the case study, we discuss potential mechanisms, managements, and clinical implications of long-COVID refractory cough problems.

7.
Food Sci Biotechnol ; 28(3): 907-911, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31093449

RESUMEN

Postprandial blood glucose lowering effect of vitamin B6 (pyridoxine) was evaluated in healthy individuals with normal blood glucose levels. Blood glucose levels were measured every 30 min for 2 h after oral sugar administration with or without 50 mg of pyridoxine. Pyridoxine significantly lowered the postprandial blood glucose levels at 30 min (from 165.95 ± 17.19 to 138.36 ± 20.43, p < 0.01) and 60 min (from 131.40 ± 17.20 to 118.50 ± 15.95) after administration. In addition, the area under the concentration-time curve (AUCt) was reduced by about 8.3% (from 257.08 ± 22.38 to 235.71 ± 12.33, p < 0.05) and the maximum concentration of blood glucose (Cmax) was reduced by about 13.8% (from 165.95 ± 17.19 to 143.07 ± 11.34, p < 0.01) when compared with those of the control group. Our findings suggest that pyridoxine supplementation may be beneficial for controlling postprandial hyperglycemia.

8.
Appl Spectrosc ; 73(3): 261-270, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30784293

RESUMEN

To deal with the general problem of biomolecule specific binding analysis, we have applied the technique of difference spectra to the surface plasmon resonance (SPR)-enhanced total internal reflection ellipsometry measurement. We suggest a three-step treatment of the SPR background that can easily be integrated with the usual measurement routine. First, making use of the difference spectrum in ellipsometric angle Δ, single peak footprints of the topmost layer are obtained that facilitate its sensitive detection during film growth. Subsequently, circumventing the need for explicit knowledge of the substrate properties, the difference spectra peaks can be used for the end-point analysis of a binding. Finally, tracking the binding effectivity of the analyte we determine the injection speed and analyte concentration windows needed for successful monitoring of the film growth. We demonstrate our approach on a comprehensive two-stage binding experiment involving two biologically relevant molecules: the C-terminal domain (CTD) of RNA polymerase II and CTD-interacting domain of one of its transcription factors, the Rtt103 protein.


Asunto(s)
ARN Polimerasa II/química , Resonancia por Plasmón de Superficie/métodos , Sitios de Unión , Unión Proteica , Dominios Proteicos , Proteínas de Saccharomyces cerevisiae/química , Factores de Transcripción/química
9.
ACS Appl Mater Interfaces ; 10(19): 16681-16689, 2018 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-29676150

RESUMEN

For organic solar cells (OSCs) based on nonplanar phthalocyanines, it has previously been reported that a thin film composed of triclinic crystals with face-on (or flat-lying)-oriented molecules, typically obtained with a CuI template layer, is desired for optical absorption in the near-infrared (NIR) spectral region. However, this work demonstrates that for a PbPc-C60 donor-acceptor pair, less face-on orientation with a broader orientation distribution obtained with a new template layer consisting of a ZnPc/CuI bilayer is more desirable in terms of solar cell efficiency than the face-on orientation. A NIR-sensitive PbPc-C60 OSC employing this bilayer-templated PbPc film is found to increase the internal quantum efficiency (IQE) by 36% on average in the NIR spectral region compared to a device using a CuI-templated PbPc film. Analyses of the change in IQE using the exciton diffusion model and the entropy- and disorder-driven charge-separation model suggest that the improved IQE is attributed to the facilitated dissociation of charge-transfer excitons as well as the reduction in exciton quenching near the indium tin oxide surface.

10.
Int J Mol Sci ; 19(3)2018 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-29543768

RESUMEN

Onion (Allium cepa L.) is widely consumed as food or medicinal plant due to its well-defined health benefits. The antioxidant and antihyperlipidemic effects of onion and its extracts have been reported well. However, very limited information on anti-hyperglycemic effect is available in processed onion extracts. In our previous study, we reported that Amadori rearrangement compounds (ARCs) produced by heat-processing in Korean ginseng can reduce carbohydrate absorption by inhibiting intestinal carbohydrate hydrolyzing enzymes in both in vitro and in vivo animal models. To prove the enhancement of anti-hyperglycemic effect and ARCs content by heat-processing in onion extract, a correlation between the anti-hyperglycemic activity and the total content of ARCs of heat-processed onion extract (ONI) was investigated. ONI has a high content of ARCs and had high rat small intestinal sucrase inhibitory activity (0.34 ± 0.03 mg/mL, IC50) relevant for the potential management of postprandial hyperglycemia. The effect of ONI on the postprandial blood glucose increase was investigated in Sprague Dawley (SD) rats fed on sucrose or starch meals. The maximum blood glucose levels (Cmax) of heat-processed onion extract were significantly decreased by about 8.7% (from 188.60 ± 5.37 to 172.27 ± 3.96, p < 0.001) and 14.2% (from 204.04 ± 8.73 to 175.13 ± 14.09, p < 0.01) in sucrose and starch loading tests, respectively. These results indicate that ARCs in onion extract produced by heat-processing have anti-diabetic effect by suppressing carbohydrate absorption via inhibition of intestinal sucrase, thereby reducing the postprandial increase of blood glucose. Therefore, enhancement of ARCs in onion by heat-processing might be a good strategy for the development of the new product on the management of hyperglycemia.


Asunto(s)
Antioxidantes/farmacología , Restricción Calórica , Hipoglucemiantes/farmacología , Cebollas/química , Extractos Vegetales/farmacología , Animales , Glucemia/metabolismo , Glucosidasas/metabolismo , Mucosa Intestinal/metabolismo , Intestinos/efectos de los fármacos , Extractos Vegetales/química , Ratas , Ratas Sprague-Dawley , Sacarasa/metabolismo
11.
Nutrients ; 10(3)2018 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-29495635

RESUMEN

In the current study, we investigated the inhibitory activity of pyridoxine, pyridoxal, and pyridoxamine, against various digestive enzymes such as α-glucosidases, sucrase, maltase, and glucoamylase. Inhibition of these enzymes involved in the absorption of disaccharide can improve post-prandial hyperglycemia due to a carbohydrate-based diet. Pyridoxal (4.14 mg/mL of IC50) had the highest rat intestinal α-glucosidase inhibitory activity, followed by pyridoxamine and pyridoxine (4.85 and 5.02 mg/mL of IC50, respectively). Pyridoxal demonstrated superior inhibition against maltase (0.38 mg/mL IC50) and glucoamylase (0.27 mg/mLIC50). In addition, pyridoxal showed significant higher α-amylase inhibitory activity (10.87 mg/mL of IC50) than that of pyridoxine (23.18 mg/mL of IC50). This indicates that pyridoxal can also inhibit starch hydrolyzing by pancreatic α-amylase in small intestine. Based on these in vitro results, the deeper evaluation of the anti-hyperglycemic potential of pyridoxine and its derivatives using Sprague-Dawley (SD) rat models, was initiated. The post-prandial blood glucose levels were tested two hours after sucrose/starch administration, with and without pyridoxine and its derivatives. In the animal trial, pyridoxal (p < 0.05) had a significantly reduction to the postprandial glucose levels, when compared to the control. The maximum blood glucose levels (Cmax) of pyridoxal administration group were decreased by about 18% (from 199.52 ± 22.93 to 164.10 ± 10.27, p < 0.05) and 19% (from 216.92 ± 12.46 to 175.36 ± 10.84, p < 0.05) in sucrose and starch loading tests, respectively, when compared to the control in pharmacodynamics study. The pyridoxal administration significantly decreased the minimum, maximum, and mean level of post-prandial blood glucose at 0.5 h after meals. These results indicate that water-soluble vitamin pyridoxine and its derivatives can decrease blood glucose level via the inhibition of carbohydrate-hydrolyzing and absorption-linked enzymes. Therefore, pyridoxal may have the potential to be used as a food ingredient for the prevention of prediabetes progression to type 2 diabetes.


Asunto(s)
Glucemia/efectos de los fármacos , Carbohidratos de la Dieta/metabolismo , Inhibidores de Glicósido Hidrolasas/farmacología , Hiperglucemia/tratamiento farmacológico , Hipoglucemiantes/farmacología , Intestino Delgado/efectos de los fármacos , Piridoxal/farmacología , Piridoxamina/farmacología , Piridoxina/farmacología , Animales , Glucemia/metabolismo , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Glucano 1,4-alfa-Glucosidasa/antagonistas & inhibidores , Glucano 1,4-alfa-Glucosidasa/metabolismo , Hidrólisis , Hiperglucemia/sangre , Hiperglucemia/enzimología , Técnicas In Vitro , Intestino Delgado/enzimología , alfa-Amilasas Pancreáticas/antagonistas & inhibidores , alfa-Amilasas Pancreáticas/metabolismo , Periodo Posprandial , Piridoxina/análogos & derivados , Ratas Sprague-Dawley , alfa-Glucosidasas/metabolismo
12.
Artículo en Inglés | MEDLINE | ID: mdl-28616204

RESUMEN

BACKGROUND: Carriage of methicillin-resistant Staphylococcus aureus (MRSA) is an important risk factor of subsequent infection. The purpose of our study was to compare the rates of subsequent infection among newly-admitted patients carrying MRSA between community-genotype and hospital-genotypes. METHODS: In this retrospective cohort study, we compared the rates of subsequent MRSA infection, time to subsequent infection and mortality in the following 6 months between the community-genotype ST72 MRSA cohort and the hospital-genotypes ST5 / ST239 MRSA cohort. RESULTS: We identified 198 patients carrying ST72 and 156 patients carrying ST5 or ST239. There was no difference in the rates of subsequent infection between ST72 cohort and ST5 / ST239 cohort (13.1% vs. 12.8%; P = 0.931). The median time to development of subsequent infection was not significantly different (27 days vs. 88 days; P = 0.0877). The Kaplan-Meier method showed no difference in the cumulative rate of being free of subsequent infection between the cohorts (P = 0.9209). Overall mortality rates at 6 months did not differ (1.5% vs. 1.9%; P = 1.000). CONCLUSIONS: We found no evidence that rates of subsequent MRSA infection were different between newly-admitted patients carrying community-genotype ST72 MRSA and those whom carrying hospital-genotypes ST5 or ST239 MRSA.

13.
Diagn Microbiol Infect Dis ; 86(4): 464-466, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27720209

RESUMEN

We investigated the prevalence of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) among methicillin-resistant S. aureus (MRSA) blood isolates collected from Korean hospitals. The hVISA prevalence in Korean hospitals has decreased during the past decade and the most significant decrease of hVISA prevalence was observed among the ST5 MRSA.


Asunto(s)
Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/microbiología , Resistencia a la Vancomicina , Bacteriemia/epidemiología , Bacteriemia/microbiología , Hospitales , Humanos , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Prevalencia , República de Corea/epidemiología
14.
Diagn Microbiol Infect Dis ; 86(3): 293-299, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27591174

RESUMEN

The aim of our study was to determine the potential for synergistic effect of vancomycin combined with a non-beta-lactam agent and of combinations of orally available non-beta-lactam agents against vancomycin-intermediate S. aureus (VISA) and heterogeneous VISA (hVISA). Three VISA isolates, three hVISA isolates, and two vancomycin-susceptible S. aureus (VSSA) isolates were used. The combinations included vancomycin and one of clindamycin, ciprofloxacin, gentamicin, rifampicin, or trimethoprim/sulfamethoxazole. Pairwise combinations among five non-beta-lactam agents were also tested for synergy. Synergy was determined using time-kill curves at 24h. Vancomycin combined with either ciprofloxacin or gentamicin showed synergy against some isolates of VISA, hVISA and VSSA. Vancomycin combined with trimethoprim/sulfamethoxazole showed synergy against VISA and hVISA. Among orally available non-beta-lactam agents, only ciprofloxacin combined with either clindamycin or trimethoprim/sulfamethoxazole showed synergy against one isolate of VISA.


Asunto(s)
Antibacterianos/farmacología , Sinergismo Farmacológico , Staphylococcus aureus/efectos de los fármacos , Resistencia a la Vancomicina/efectos de los fármacos , Vancomicina/farmacología , Bacteriemia/microbiología , Humanos , Pruebas de Sensibilidad Microbiana , Viabilidad Microbiana/efectos de los fármacos , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/aislamiento & purificación , Staphylococcus aureus/fisiología
15.
J Nanosci Nanotechnol ; 16(6): 6445-9, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27427733

RESUMEN

The epidermal growth factor receptor (EGFR) protein has received significant attention in medical biotechnology because it is an important component in cell growth and division. We report the results of a study on the binding between the EGFR protein and the associated aptamer, measured in real time. Aptamers can be used for clinical purposes including macromolecular medicine and basic research. In particular, EGFR aptamers are promising molecular agents for targeting cancer. The data were obtained in-situ with total internal reflection ellipsometry (TIRE), which combines the analytic capability of spectroscopic ellipsometry with the high surface sensitivity of surface plasmon resonance measurements. Our results show that TIRE can be used to determine adsorption of nanoscale biomolecules. Our results are supported by additional data obtained by liquid atomic-force-microscopy.


Asunto(s)
Aptámeros de Nucleótidos/metabolismo , Receptores ErbB/metabolismo , Fenómenos Ópticos , Resonancia por Plasmón de Superficie/métodos , Adsorción , Aptámeros de Nucleótidos/genética , Secuencia de Bases , Oro/química , Humanos , Unión Proteica
16.
Food Sci Biotechnol ; 25(3): 899-904, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-30263351

RESUMEN

Policosanol is a well-defined nutraceutical for the management of blood cholesterol levels. The present study examined (i) the effect of policosanol supplementation on blood cholesterol and glucose levels and (ii) changes in hepatic cholesterol biosynthesis using 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase) activity in Wistar rats fed high cholesterol diets. The Wistar rats were assigned randomly to high-cholesterol diets (1.25% cholesterol) with or without policosanol (8.0 mg/kg body weight) for 6 weeks. Compared with the control group, dietary treatment with policosanol resulted in a significant decrease of blood cholesterol (p<0.01), blood glucose (p<0.01), triglyceride (p<0.001), and low density lipoprotein-cholesterol levels (p<0.01) and HMG-CoA reductase activity (p<0.001) in the liver. These results indicate that policosanol decreases blood cholesterol levels by suppressing cholesterol biosynthesis via decrease of HMG-CoA activity. Policosanol has the potential to be developed into an effective dietary strategy for both postprandial hyperglycemia and hypercholesterolemia.

17.
Food Sci Biotechnol ; 25(3): 911-914, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-30263353

RESUMEN

The effect of chitosan oligosaccharide (GO2KA1) administration on postprandial blood glucose levels of subjects with normal blood glucose levels was evaluated following bread consumption. Postprandial blood glucose levels were determined for 2 h after bread ingestion with or without 500 mg of GO2KA1. GO2KA1 significantly lowered the mean, maximum, and minimum levels of postprandial blood glucose at 30 min after the meal. Postprandial blood glucose levels were decreased by about 25% (from 155.11±13.06 to 138.50±13.59, p<0.01) at 30 min when compared to control. Furthermore, we observed that the area under the concentration-time curve (AUCt) was decreased by about 6% (from 255.46±15.43 to 240.15±14.22, p<0.05) and the peak concentration of blood glucose (C max) was decreased by about 11% (from 157.94±10.90 to 140.61±12.52, p<0.01) when compared to control. However, postprandial the time to reach C max (Tmax) levels were the same as those found in control. Our findings suggest that GO2KA1 limits the increase in postprandial blood glucose levels following bread consumption.

18.
Int J Antimicrob Agents ; 46(3): 338-41, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25982914

RESUMEN

Although heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) has been increasingly reported, the true prevalence of hVISA is unclear, especially in Asia. In this study, the genotype-specific prevalence of hVISA among meticillin-resistant S. aureus (MRSA) clinical isolates collected from Asian countries was determined. Among MRSA collections from South Korea, Taiwan, Hong Kong, Thailand, the Philippines, Vietnam, India and Sri Lanka in the ANSORP surveillance study during 2004 and 2006, isolates with a vancomycin minimum inhibitory concentration of ≥0.25mg/L were randomly selected. After screening by macro Etest, hVISA was confirmed using the modified population analysis profile method. MRSA isolates were typed by spa tying and multilocus sequence typing (MLST). Among 462 MRSA isolates, 16 (3.5%) were confirmed as hVISA. The proportion of hVISA was highest in South Korea and Vietnam (both 7.0%), followed by Thailand (3.2%) and Taiwan (1.9%). spa type t601 belonging to clonal complex (CC) 5 showed the highest proportion of hVISA (33.3%), and hVISA accounted for 6.9% among isolates of t002 belonging to CC5. Among CC239 isolates, only those of t037 were hVISA (1.6%). Among isolates of community-associated MRSA genotypes, hVISA was found only in those of t437 (4.8%) belonging to CC59, and no hVISA was found among those of CC30 or CC72. The prevalence of hVISA in the Asian region differed by country and was dependent upon the genotype of MRSA strains. It suggests that differences in hVISA prevalence between countries can be affected by the genotype distribution of MRSA strains.


Asunto(s)
Genotipo , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/genética , Infecciones Estafilocócicas/microbiología , Resistencia a la Vancomicina , Asia/epidemiología , Humanos , Staphylococcus aureus Resistente a Meticilina/clasificación , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Epidemiología Molecular , Tipificación Molecular , Prevalencia , Infecciones Estafilocócicas/epidemiología
19.
J Nanosci Nanotechnol ; 14(11): 8715-8, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25958590

RESUMEN

The dielectric functions of amorphous GdAlO(x) (GAO) films grown by the sol-gel process were investigated from 1.12 to 8.5 eV as a function of annealing temperature using spectroscopic ellipsometry (SE). A GAO precursor sol with a molar ratio of Gd:Al = 1:1 was prepared. Thin layers were formed by spin-coating on p-type Si substrates. The layers were sintered at 400 degrees C for 2 h in an ambient atmosphere, then rapid-thermal-annealed (RTA) at 700 or 800 degrees C for 1 min in an N2 ambient. The optical properties were measured via variable angle SE, at room temperature. The angle of incidence was varied from 50 to 70 degrees in 10 degrees steps. The dielectric functions of the resulting GAO films were obtained from the measured pseudodielectric functions by multilayer-structure calculations using the Tauc-Lorentz (TL) dispersion relation. The real and imaginary parts of the dielectric functions were found to increase with increasing RTA temperature. The film thicknesses and TL parameters (threshold energy E(g) and broadening C) decrease with increasing RTA temperature.

20.
IEEE Trans Biomed Circuits Syst ; 7(4): 426-36, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23893202

RESUMEN

A wavelet Electrocardiogram (ECG) detector for low-power implantable cardiac pacemakers is presented in this paper. The proposed wavelet-based ECG detector consists of a wavelet decomposer with wavelet filter banks, a QRS complex detector of hypothesis testing with wavelet-demodulated ECG signals, and a noise detector with zero-crossing points. In order to achieve high detection accuracy with low power consumption, a multi-scaled product algorithm and soft-threshold algorithm are efficiently exploited in our ECG detector implementation. Our algorithmic and architectural level approaches have been implemented and fabricated in a standard 0.35 µm CMOS technology. The testchip including a low-power analog-to-digital converter (ADC) shows a low detection error-rate of 0.196% and low power consumption of 19.02 µW with a 3 V supply voltage.


Asunto(s)
Electrocardiografía/instrumentación , Electrodos Implantados , Marcapaso Artificial , Análisis de Ondículas , Algoritmos , Conversión Analogo-Digital , Diseño de Equipo , Humanos , Procesamiento de Señales Asistido por Computador
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