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1.
J Dairy Sci ; 105(5): 3861-3870, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35248374

RESUMEN

Modification of milk fat composition might be a desirable method to alter manufacturing characteristics or produce dairy products low in saturated fat that more closely meet consumer dietary preferences. The aim of this research was to evaluate functional properties of cream obtained from milks with fat composition modified by altering the profile of long-chain fatty acids (FA) absorbed from the intestine. A control and 5 mixtures of long-chain free FA were infused into the abomasum of lactating dairy cows in a 6 × 6 Latin square design with 21-d periods. Treatments were as follows: (1) control (no FA infused), (2) mostly saturated FA (C16:C18 = 0.74), (3) low linoleic palm FA (C16:C18 = 0.73), (4) palm FA (C16:C18 = 0.73), (5) soy FA (C16:C18 = 0.10), and (6) high palmitic soy FA (C16:C18 = 0.73). All treatments included meat solubles and Tween 80 as emulsifiers. Viscosity, overrun, whipping time, foam firmness, and foam stability were evaluated in creams (33% fat). Cream from cows infused with soy FA (treatment 5) had the longest whipping time and lowest overrun, foam stability, viscosity, melting point, firmness, and solid fat content at 5 and 20°C because the fat had the highest unsaturated FA content. Increasing palmitic acid content of soy FA (treatment 6) improved functional variables in cream relative to soy FA alone. Differences among treatments 1 to 4 were less pronounced because of the effect of C18:1 trans in treatments 3 and 4 on milk fat yield and composition. Milk fat from cows infused with palm FA (treatment 4) exhibited comparable or better functionality than control cream. Increased polyunsaturated FA in milk fat resulted in increased amounts of triglyceride (TG) fractions with 28, 30, 38, and 40 carbon numbers, increased oleic acid resulted in increased 50-carbon TG, and higher palmitic and myristic acids resulted in greater 44, 46, and 48 carbon number TG. These TG groups consistently correlated with functional properties of creams from different treatments. Our results indicated that optimal functionality of cream is dependent more on its content of palmitic acid than on unsaturated FA. However, an optimal composition of milk fat for cream functional characteristics might be obtained through nutritional manipulation of diets for dairy cows to deliver an optimal profile of FA.


Asunto(s)
Lactancia , Leche , Alimentación Animal/análisis , Animales , Carbono , Bovinos , Dieta/veterinaria , Suplementos Dietéticos , Ácidos Grasos , Femenino , Ácido Palmítico , Triglicéridos
2.
Nervenarzt ; 91(1): 10-17, 2020 Jan.
Artículo en Alemán | MEDLINE | ID: mdl-31858162

RESUMEN

The last two decades of clinical research have clearly demonstrated the comprehensive benefits of the early recognition and treatment of psychotic disorders. The attenuated and transient positive symptoms according to the ultrahigh risk criteria and the basic symptom criterion "Cognitive disturbances" are the main approaches for an indicated prevention. They have recently been recommended as criteria for a clinical high-risk (CHR) state of psychosis by the European Psychiatric Association (EPA) and, following these, in the German S3 guidelines for the treatment of schizophrenia by the German Association for Psychiatry, Psychotherapy and Psychosomatics (DGPPN); however, the efficacy of early treatment of patients with a CHR for psychoses critically depends on the development of prognostic instruments, which enable healthcare professionals to reliably identify these patients based on the individual objective risk profiles. An important goal is the treatment of functional deficits, which can be identified by an individual risk profile. The treatment of existing comorbid mental disorders, psychosocial problems and the prevention of potential future disorders also characterizes the recommendations of the EPA and DGPPN for early treatment, which favor psychotherapeutic, especially cognitive behavioral interventions over pharmacological treatment. The close interdisciplinary cross-sectoral cooperation between the disciplines of child and adolescent psychiatry, and adult psychiatry is of outstanding importance in this context.


Asunto(s)
Trastornos Psicóticos , Esquizofrenia , Adolescente , Adulto , Niño , Terapia Cognitivo-Conductual , Humanos , Psicoterapia , Trastornos Psicóticos/diagnóstico , Trastornos Psicóticos/prevención & control , Trastornos Psicóticos/terapia , Esquizofrenia/diagnóstico , Esquizofrenia/prevención & control , Esquizofrenia/terapia
3.
Encephale ; 43(3): 292-297, 2017 May.
Artículo en Francés | MEDLINE | ID: mdl-28347521

RESUMEN

In children and adolescents, psychotic disorders already represent one of the leading causes of disability-adjusted life years. During the past two decades, early detection of risk for psychosis has been intensively investigated, and in particular, predictive power for early signs of risk has been initiated and translated into clinical practice. In particular, the attenuated and transient positive symptoms of the ultra-high risk criteria, and the basic symptom criterion "cognitive disturbances", open promising routes to an indicated prevention and have recently been considered by the European Psychiatric Association (EPA) as diagnostic criteria of a psychosis-risk syndrome. The EPA recently provided evidence-based recommendations on the early detection of clinical high risk (CHR) for psychosis in patients with mental distress. In 2015, experts in the field of early detection conducted a meta-analysis reporting on studies examining conversion rates to psychosis in non-overlapping samples meeting at least one of the main CHR criteria: ultra-high risk (UHR) and/or basic symptoms criteria, examining the effects of potential moderators (different UHR criteria definitions, single UHR criteria and age) on conversion rates. In the 42 identified samples, comprising more than 4000 CHR patients who had been mainly identified by means of UHR criteria and/or the basic symptom criterion 'cognitive disturbances' (COGDIS), conversion rates showed considerable heterogeneity. While UHR and COGDIS criteria were related to comparable conversion rates until a 2-year follow-up, rates for COGDIS were significantly higher for follow-up periods beyond 2 years. Differences in onset and frequency requirements of symptomatic UHR criteria, or in their different consideration of functional decline, substance use and co-morbidity, did not seem to have an impact on conversion rates. The 'genetic risk and functional decline' UHR criterion was rarely met and only showed an insignificant pooled sample effect. However, age significantly affected UHR conversion rates with lower rates in children and adolescents. Although more research into potential sources of heterogeneity in conversion rates is needed to facilitate improvement of CHR criteria, six evidence-based recommendations for the early detection of psychosis were developed as a basis for the EPA guidance on early intervention in CHR states. The EPA guidance on early intervention aimed to provide evidence-based recommendations on early intervention in CHR states of psychosis, assessed according to the EPA guidance on early detection. The recommendations were also made by experts in the field of early intervention in psychoses and derived from a meta-analysis of current empirical evidence on the efficacy of psychological and pharmacological interventions in CHR samples. Eligible studies had to investigate conversion rate and/or functioning as a treatment outcome in CHR patients defined by the ultra-high risk and/or basic symptom criteria. In addition to analyses of treatment effects on conversion rate and functional outcome, age and type of intervention were examined as potential moderators. Based on data from 15 studies (n=1394), early intervention generally produced significantly reduced conversion rates at 6- to 48-month follow-up compared to control conditions. However, early intervention failed to achieve significantly greater functional improvements because both early intervention and control conditions produced similar positive effects. With regard to the type of intervention, both psychological and pharmacological interventions produced significant effects on conversion rates but not on functional outcome relative to the control conditions. Early intervention in youth samples was generally less effective than in predominantly adult samples. Seven evidence-based recommendations for early intervention in CHR samples have been formulated, although more studies are needed to investigate the specificity of treatment effects and potential age effects in order to tailor interventions to the individual treatment needs and risk status. Overall, age-related specificities and developmental transitions in the early detection and intervention in psychoses should be better accounted for in future research.


Asunto(s)
Intervención Médica Temprana , Trastornos Psicóticos/diagnóstico , Trastornos Psicóticos/terapia , Adolescente , Adulto , Niño , Diagnóstico Precoz , Humanos , Escalas de Valoración Psiquiátrica , Trastornos Psicóticos/psicología , Gestión de Riesgos , Esquizofrenia/diagnóstico , Esquizofrenia/terapia , Psicología del Esquizofrénico
4.
Eur Psychiatry ; 30(3): 405-16, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25735810

RESUMEN

The aim of this guidance paper of the European Psychiatric Association is to provide evidence-based recommendations on the early detection of a clinical high risk (CHR) for psychosis in patients with mental problems. To this aim, we conducted a meta-analysis of studies reporting on conversion rates to psychosis in non-overlapping samples meeting any at least any one of the main CHR criteria: ultra-high risk (UHR) and/or basic symptoms criteria. Further, effects of potential moderators (different UHR criteria definitions, single UHR criteria and age) on conversion rates were examined. Conversion rates in the identified 42 samples with altogether more than 4000 CHR patients who had mainly been identified by UHR criteria and/or the basic symptom criterion 'cognitive disturbances' (COGDIS) showed considerable heterogeneity. While UHR criteria and COGDIS were related to similar conversion rates until 2-year follow-up, conversion rates of COGDIS were significantly higher thereafter. Differences in onset and frequency requirements of symptomatic UHR criteria or in their different consideration of functional decline, substance use and co-morbidity did not seem to impact on conversion rates. The 'genetic risk and functional decline' UHR criterion was rarely met and only showed an insignificant pooled sample effect. However, age significantly affected UHR conversion rates with lower rates in children and adolescents. Although more research into potential sources of heterogeneity in conversion rates is needed to facilitate improvement of CHR criteria, six evidence-based recommendations for an early detection of psychosis were developed as a basis for the EPA guidance on early intervention in CHR states.


Asunto(s)
Diagnóstico Precoz , Intervención Médica Temprana/estadística & datos numéricos , Trastornos Psicóticos/diagnóstico , Trastornos Psicóticos/terapia , Adolescente , Adulto , Antipsicóticos/uso terapéutico , Niño , Trastornos del Conocimiento/diagnóstico , Femenino , Humanos , Masculino , Trastornos del Humor/diagnóstico , Trastornos del Humor/terapia , Guías de Práctica Clínica como Asunto , Escalas de Valoración Psiquiátrica , Medición de Riesgo , Factores de Riesgo , Esquizofrenia/diagnóstico , Esquizofrenia/terapia , Resultado del Tratamiento , Adulto Joven
5.
Eur Psychiatry ; 30(3): 388-404, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25749390

RESUMEN

This guidance paper from the European Psychiatric Association (EPA) aims to provide evidence-based recommendations on early intervention in clinical high risk (CHR) states of psychosis, assessed according to the EPA guidance on early detection. The recommendations were derived from a meta-analysis of current empirical evidence on the efficacy of psychological and pharmacological interventions in CHR samples. Eligible studies had to investigate conversion rate and/or functioning as a treatment outcome in CHR patients defined by the ultra-high risk and/or basic symptom criteria. Besides analyses on treatment effects on conversion rate and functional outcome, age and type of intervention were examined as potential moderators. Based on data from 15 studies (n=1394), early intervention generally produced significantly reduced conversion rates at 6- to 48-month follow-up compared to control conditions. However, early intervention failed to achieve significantly greater functional improvements because both early intervention and control conditions produced similar positive effects. With regard to the type of intervention, both psychological and pharmacological interventions produced significant effects on conversion rates, but not on functional outcome relative to the control conditions. Early intervention in youth samples was generally less effective than in predominantly adult samples. Seven evidence-based recommendations for early intervention in CHR samples could have been formulated, although more studies are needed to investigate the specificity of treatment effects and potential age effects in order to tailor interventions to the individual treatment needs and risk status.


Asunto(s)
Diagnóstico Precoz , Intervención Médica Temprana/estadística & datos numéricos , Guías de Práctica Clínica como Asunto , Trastornos Psicóticos/diagnóstico , Trastornos Psicóticos/terapia , Adolescente , Adulto , Antipsicóticos/uso terapéutico , Humanos , Masculino , Trastornos del Humor/diagnóstico , Trastornos del Humor/terapia , Escalas de Valoración Psiquiátrica , Factores de Riesgo , Esquizofrenia/diagnóstico , Esquizofrenia/terapia , Resultado del Tratamiento
6.
J Viral Hepat ; 21(1): 74-6, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24112755

RESUMEN

This single-arm, open-label, descriptive study assessed the efficacy and safety of entecavir (ETV) in nucleos(t)ide-naïve Black/African American patients with chronic hepatitis B (CHB), a patient population underrepresented in ETV registration trials. Forty patients with HBeAg(+) or HBeAg(-) compensated CHB of self-described Black/African American race received ETV 0.5 mg daily for 52 weeks; 37 patients completed 52 weeks of treatment. At Week 48, 29/40 (72.5%, noncompleter = failure) patients achieved the primary endpoint of HBV DNA <50 IU/mL. Rates for HBeAg loss (11/22; 50%) and HBeAg seroconversion (9/22; 41%) were high, possibly due to the high HBV genotype A prevalence (70%). No patient experienced virological breakthrough. Samples for resistance testing were available in 6/8 patients with HBV DNA >50 IU/mL at Week 48 or last on-treatment visit. No ETV resistance was detected. The safety profile of ETV was consistent with that observed in ETV registration trials. This study shows that in Black/African American patients with CHB, ETV was well tolerated and demonstrated comparable antiviral efficacy to that observed in White and Asian patients in ETV Phase III studies.


Asunto(s)
Antivirales/administración & dosificación , Guanina/análogos & derivados , Hepatitis B Crónica/tratamiento farmacológico , Adulto , Negro o Afroamericano , Antivirales/efectos adversos , Antivirales/farmacología , ADN Viral/sangre , Femenino , Guanina/administración & dosificación , Guanina/efectos adversos , Guanina/farmacología , Antígenos e de la Hepatitis B/sangre , Virus de la Hepatitis B/efectos de los fármacos , Virus de la Hepatitis B/aislamiento & purificación , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Resultado del Tratamiento , Carga Viral
7.
J Food Sci ; 73(2): E69-81, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18298728

RESUMEN

Mold growth is a common problem during the equilibration of food materials at high relative humidity values using the standard saturated salt slurry method. Exposing samples to toluene vapor and mixing samples with mold inhibitor chemicals are suggested methods for preventing mold growth while obtaining isotherms. However, no published research was found that examined the effect of mold growth on isotherm performance or the efficacy of various mold inhibitor methods, including their possible effect on the physicochemical properties of food materials. Therefore, the objectives of this study were to (1) explore the effect of mold growth on isotherm performance in a range of food materials, (2) investigate the effectiveness of 4 mold inhibitor methods, irradiation, 2 chemical inhibitors (potassium sorbate and sodium acetate), and toluene vapor, on mold growth on dent corn starch inoculated with A. niger, and (3) examine the effect of mold inhibitor methods on the physicochemical properties of dent corn starch, including isotherm performance, pasting properties, gelatinization temperature, and enthalpy. Mold growth was found to affect starch isotherm performance by contributing to weight changes during sample equilibration. Among the 4 mold inhibitor methods tested, irradiation and toluene vapor were found to be the most effective for inhibiting growth of A. niger on dent cornstarch. However, both methods exhibited a significant impact on the starches' physiochemical properties, suggesting the need to probe the efficacy of other mold inhibitor methods and explore the use of new rapid isotherm instruments, which hamper mold growth by significantly decreasing measurement time.


Asunto(s)
Antifúngicos/farmacología , Aspergillus niger/crecimiento & desarrollo , Contaminación de Alimentos/prevención & control , Conservación de Alimentos/métodos , Zea mays/microbiología , Adsorción , Contaminación de Alimentos/análisis , Manipulación de Alimentos/métodos , Irradiación de Alimentos , Microbiología de Alimentos , Tecnología de Alimentos/métodos , Humanos , Humedad , Almidón , Termodinámica , Factores de Tiempo , Tolueno/farmacología , Zea mays/química
8.
J Food Sci ; 73(1): E25-35, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18211350

RESUMEN

The moisture sorption behavior of freeze-dried amorphous sucrose was investigated using a dynamic humidity generating instrument, the Dynamic Vapor Sorption (DVS) instrument. The kinetic moisture sorption profiles of freeze-dried amorphous sucrose samples with 29% crystalline content were obtained using the DVS instrument at 9 relative humidity (RH) values, ranging from 10% to 90%, at 25 degrees C. Moisture-induced crystallization was observed for %RH values between 40% and 80%, where the crystallization onset time decreased as %RH increased. The moisture sorption behavior of freeze-dried amorphous sucrose with 3 crystalline contents, 23%, 29%, and 80%, was also compared, revealing that the crystalline content had a significant impact on the pseudo-sorption isotherm of freeze-dried amorphous sucrose. In general, for %RH values below 90%, samples that had a lower percent crystalline content had a higher pseudo-equilibrium moisture content, with the difference becoming most pronounced for the 60% to 80% RH values. The moisture-induced crystallization results as a function of %RH obtained in this study were compared to those previously reported in the literature, leading to an extensive discussion of both the experimental protocols used and the hypothesized mechanisms governing the long-term stability of amorphous materials. The hypothesized mechanisms discussed included the glass transition temperature boundary, the zero mobility temperature, and the hydration limit. Based on the dissimilarity in these hypothesized mechanisms, additional theoretical and experimental exploration is still merited in order to adequately predict the conditions (for example, moisture content, %RH, and temperature) required to ensure long-term stability of amorphous solids.


Asunto(s)
Cristalización/métodos , Liofilización , Humedad , Sacarosa/química , Adsorción , Cinética , Transición de Fase , Temperatura
9.
J Food Sci ; 72(1): S001-11, 2007 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17995891

RESUMEN

Bulk sweeteners provide functional properties in beverages, including sweet taste, bulking, bitter masking, structure, and mouthfeel. Diet beverages come closer to the taste of regular beverages using a blend of high-intensity sweeteners; however, some properties, including bulking, structure, and mouthfeel, remain significantly different. Relating physical properties to sensory characteristics is an important step in understanding why mouthfeel differences are apparent in beverages sweetened with alternative sweeteners compared to bulk sweeteners. The objectives of this research were to (1) measure sweetener profile, Brix, refractive index, viscosity, a(w), carbonation, titratable acidity, and pH of commercial carbonated beverages; and (2) correlate the physical property measurements to descriptive analysis of the beverages. Correlation analysis, partial least squares, canonical correlation analysis, and cluster analysis were used to analyze the data. Brix, viscosity, and sweet taste were highly correlated among one another and were all negatively correlated to a(w). Carbonated and decarbonated pH were highly correlated to each other and were both negatively correlated to mouthcoating. Numbing, burn, bite, and carbonation were highly correlated to total acidity, citric acid, and ascorbic acid and negatively correlated to phosphoric acid. The mouthfeel difference between diet and regular lemon/lime carbonated beverages is small and may be related to overall differences between flavor, acid, and sweetener types and usage levels. This research is significant because it demonstrates the use of both sensory attributes and physical properties to identify types of ingredients and levels that may decrease the mouthfeel perception differences between regular and diet carbonated beverages, which could consequently lead to higher acceptance of diet beverages by the consumers of regular.


Asunto(s)
Bebidas Gaseosas/análisis , Bebidas Gaseosas/normas , Química Física , Tecnología de Alimentos , Edulcorantes/análisis , Fenómenos Químicos , Comportamiento del Consumidor , Análisis de los Alimentos , Humanos , Concentración de Iones de Hidrógeno , Gusto , Viscosidad
10.
J Dairy Sci ; 90(11): 5018-31, 2007 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-17954741

RESUMEN

Modification of milk fat composition might be desirable to alter manufacturing characteristics or produce low saturated fat dairy products that more closely meet consumer dietary preferences. The aim of this research was to evaluate functional properties of butter oil obtained from milks with fat composition modified by altering the profile of long-chain fatty acids (FA) absorbed from the small intestine of cows. A control and 5 mixtures of long-chain free FA were infused into the abomasum of lactating dairy cows in a 6 x 6 Latin square design with 21-d periods. Treatments were 1) control (no FA infused), 2) mostly saturated FA (C16:C18 = 0.72), 3) low-linoleic palm FA (C16:C18 = 0.85), 4) palm FA (C16:C18 = 0.72), 5) soy FA (C16:C18 = 0.10), and 6) high-palmitic soy FA (C16:C18 = 0.68). All treatments included meat solubles and Tween 80 as emulsifiers. Solid fat content (from 0 to 40 degrees C), melting point, and force at fracture were determined in butter oil. Milk fat from cows infused with palm FA (treatment 4) exhibited functionality equal to or better than control butter oil. Infusion with palm FA increased amounts of triglyceride (TG) fractions with 48, 52, and 54 carbon numbers but decreased TG with 32, 34, 36, and 42 carbon numbers. Infusion with soy FA increased TG with 26, 38, 40, 52, and 54 carbon numbers but decreased TG with 34, 42, and 46 carbons. Infusion of the mostly saturated FA increased TG with 38, 50, 52, and 54 carbon numbers but decreased TG with 32, 34, and 42 carbon numbers. These TG groups were consistently correlated with functional properties of butter oils from different treatments. The content of palmitic acid is important for maintaining functionality in the presence of increased polyunsaturated FA. The composition of milk fat may be able to be optimized through nutritional manipulation of diets for dairy cows if the optimal composition of FA and TG is defined for a particular dairy product.


Asunto(s)
Mantequilla/análisis , Bovinos/fisiología , Grasas de la Dieta/análisis , Grasas/metabolismo , Ácidos Grasos/metabolismo , Abomaso/fisiología , Animales , Carbono/análisis , Frío , Grasas/administración & dosificación , Femenino , Calor , Lactancia/fisiología , Leche/química , Aceite de Palma , Ácido Palmítico/administración & dosificación , Aceites de Plantas/administración & dosificación , Triglicéridos/análisis , Triglicéridos/química
11.
Trop Anim Health Prod ; 38(3): 249-60, 2006 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-16986772

RESUMEN

The objectives of this study were to assess the gestational, periparturient and preweaning growth traits of Holstein vs Gir x Holstein (G x H F1) cross-bred dairy calves. Holstein cows (n=64) pregnant with Holstein (H x H) calves (bulls, n=16; heifers, n=18) or G x H (bulls, n=8; heifers, n=22) calves were sampled from 60 days of gestation through calving for serum progesterone (P4) and in utero placentome sizes, and at parturition for calving ease scores (CES), calf vigour scores (CVS), and placental characteristics. Post-calving calf measures included birth weight (day 0) and body weight (kg), hip width (HW), body length (BL), wither height (WH), hip height (HH) and heart girth (HG) through 42 days of age. Serum IgG and calf vital function tests (respiration rate (RR), heart rate (HR), rectal temperature (RT) and fecal scores) were recorded on days 1, 3, 7 and 14 of age (a.m. and p.m.). Serum gestational P4 was higher (p < 0.05) for cows with H x H than G x H calves. Placentome measurements in utero were greater (p < 0.01) for H x H calves than for G x H calves, while at parturition placental characteristics did not differ (p > 0.10). Gestation length, CES and CVS also did not differ (p > 0.10) between H x H and G x H calves. Calf RR and HR were higher (p < 0.05) for H x H than G x H calves at both a.m. and p.m., while RT, fecal scores and serum IgG did not differ (p > 0.10) between H x H and G x H calves. Birth weight did not differ (p > 0.10) between H x H and G x H calves within sex. Moreover, bulls did not differ (p > 0.10) in any of the growth measures between H x H and G x H calves, whereas H x H heifers at days 28 and 42 of age were greater (p < 0.05) in all growth traits than G x H heifers. Nevertheless, the relative change in growth measures over time (days 0 to 42) did not differ (p > 0.10) between H x H and G x H calves. While subtle differences in gestational, early growth and vital function characteristics were observed, these data suggest very similar developmental profiles between H x H and G x H calves.


Asunto(s)
Animales Recién Nacidos/crecimiento & desarrollo , Cruzamiento/métodos , Bovinos , Cruzamientos Genéticos , Preñez/fisiología , Animales , Animales Recién Nacidos/genética , Peso al Nacer , Bovinos/genética , Bovinos/crecimiento & desarrollo , Bovinos/fisiología , Femenino , Desarrollo Fetal/genética , Desarrollo Fetal/fisiología , Masculino , Embarazo , Preñez/genética , Progesterona/sangre , Reproducción/genética , Reproducción/fisiología , Selección Genética , Aumento de Peso/genética , Aumento de Peso/fisiología
12.
J Agric Food Chem ; 48(10): 4469-76, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11052686

RESUMEN

An examination of the methods for nuclear magnetic cross-relaxation spectroscopy (CRS) data collection and analysis was conducted using water and an aqueous waxy corn starch suspension to better perform and interpret the results obtained using CRS. The CRS data collection properties evaluated were the time to achieve steady state saturation, the direct saturation of liquid protons, generation of transverse magnetization, and dependence of the offset frequency and radio frequency (RF) field strength of longitudinal relaxation in the presence of RF saturation. Effects were evaluated for variations of input values of RF saturation field strength, apparent cross-relaxation rate, and solid longitudinal relaxation rate on the results for solid content and solid internal mobility from fitting NMR data to modified theoretical expressions. Discrepancies between fitted and stoichiometric values for the solid to liquid proton ratio were investigated. The fitting procedure used a Gaussian line shape for RF saturation of the solid-like spin system and a Lorentzian line shape for RF saturation of the liquid-spin system. Conditions under which acceptable results can be obtained with limited data sets are discussed.


Asunto(s)
Almidón/química , Zea mays/química , Algoritmos , Espectroscopía de Resonancia Magnética , Reproducibilidad de los Resultados
14.
J Med Chem ; 39(26): 5035-46, 1996 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-8978834

RESUMEN

A series of N-hydroxyurea derivatives have been prepared and examined as inhibitors of 5-lipoxygenase. Oral activity was established by examining the inhibition of LTB4 biosynthesis in an ex vivo assay in the mouse. The pharmacodynamic performance in the mouse of selected compounds was assessed using an ex vivo LTB4 assay and an adoptive peritoneal anaphylaxis assay at extended pretreat times. Compounds with an extended duration of action were re-examined as the individual enantiomers in the ex vivo assay, and the (S) enantiomer of N-hydroxy-N-[2,3-dihydro-6-(phenylmethoxy)-3-benzofuranyl]urea, (+)-1a (SB 202235), was selected as the compound with the best overall profile. Higher plasma concentrations and longer plasma half-lives were found for (+)-1a relative to its enantiomer in the mouse, monkey, and dog. In vitro metabolic studies in mouse liver microsomes established enantiospecific glucuronidation as a likely mechanism for the observed differences between the enantiomers of 1a. Enantioselective glucuronidation favoring (-)-1a was also found in human liver microsomes.


Asunto(s)
Benzofuranos/farmacología , Inhibidores de la Lipooxigenasa , Inhibidores de la Lipooxigenasa/farmacología , Urea/análogos & derivados , Animales , Benzofuranos/química , Benzofuranos/farmacocinética , Cromatografía Líquida de Alta Presión , Perros , Humanos , Inhibidores de la Lipooxigenasa/química , Inhibidores de la Lipooxigenasa/farmacocinética , Macaca fascicularis , Espectroscopía de Resonancia Magnética , Masculino , Ratones , Estereoisomerismo , Urea/química , Urea/farmacocinética , Urea/farmacología
15.
Crit Rev Food Sci Nutr ; 36(4): 357-85, 1996 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-8740439

RESUMEN

The physical and chemical changes that occur in foods during growth, harvest, processing, storage, preparation, and consumption are often very difficult to measure and quantify. Magnetic resonance imaging (MRI) is a pioneering technology, originally developed in the medical field, that is now being used in a large number of disciplines to study a wide variety of materials and processes. In food science, MRI techniques allow the interior of foods to be imaged noninvasively and nondestructively. These images can then be quantified to yield information about several processes and material properties, such as mass and heat transfer, fat and ice crystallization, gelation, water mobidity, composition and volume changes, food stability and maturation, flow behavior, and temperature. This article introduces the fundamental principles of MRI, presents some of the recent advances in MRI technology, and reviews some of the current applications of MRI in food science research.


Asunto(s)
Tecnología de Alimentos , Imagen por Resonancia Magnética , Análisis de los Alimentos , Manipulación de Alimentos , Humanos , Imagen por Resonancia Magnética/métodos , Espectroscopía de Resonancia Magnética , Control de Calidad
17.
J Med Chem ; 35(1): 100-6, 1992 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-1732516

RESUMEN

A series of side chain modified analogues of cholesterol and lanosterol (1-10) have been synthesized and evaluated as inhibitors of the Candida albicans delta 24-sterol methyltransferase. Two sterol substrate analogues 1 and 2 which contained a 24-thia substituent were relatively modest inhibitors of the enzyme (Ki = 1.5-72 microM). Compounds which mimic the carbocation intermediates proposed for the methyltransferase reaction, including sulfonium salts 4-6, amidines 7 and 8, and imidazoles 9 and 10 were substantially more potent inhibitors (Ki = 5-500 nM). All of the sterol analogues examined displayed less than 10-fold selectivity for inhibition of the methyltransferase versus the rat liver delta 24-sterol reductase. The sterol analogues were tested for in vitro antifungal activity against C. albicans, Candida tropicalis, and Torulopsis glabrata. The minimum inhibitory concentrations versus C. albicans correlated well with the Ki values for methyltransferase inhibition, and the potency of several compounds approached that of amphotericin B, although only modest fungicidal activity was observed.


Asunto(s)
Antifúngicos/síntesis química , Colesterol/análogos & derivados , Lanosterol/análogos & derivados , Metiltransferasas/antagonistas & inhibidores , Antifúngicos/farmacología , Candida albicans/efectos de los fármacos , Candida albicans/enzimología , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Pruebas de Sensibilidad Microbiana , Relación Estructura-Actividad
18.
J Anim Sci ; 69(3): 1255-71, 1991 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-1648066

RESUMEN

The purpose of this study was to isolate, using both in situ and in vivo methodology, the nonfermented fiber fraction of oat hulls (OH) and cottonseed hulls (CSH) and to compare the concentrations of alkali-labile phenolic monomers, nitrobenzene oxidizable phenolic monomers, and neutral monosaccharides, as well as the cross polarization/magic angle spinning (CP/MAS) carbon-13 (13C) nuclear magnetic resonance (NMR) spectra, of the nonfermented fraction with the original OH or CSH. The in situ isolation procedure involved a 30-h ruminal pretreatment and an 8-h acid:pepsin pretreatment followed by 1 to 7 additional days of incubation in the rumen. Fractions not fermented in vivo were isolated from duodena, ileal, and fecal material obtained from a site and extent of digestion trial in which these byproducts were fed to sheep at 80% of the diet (as-fed basis) and they represented the sole source of dietary fiber. Based on nonfermented fraction composition, both in situ and in vivo, all components analyzed were degraded to some extent. Also, all components present in original byproduct material were present in both the in situ and in vivo nonfermented fractions. Based on NMR analysis, cellulose crystallinity did not change during either long-term in situ or in vivo fermentation. However, CSH cellulose was more crystalline than that of OH. The ADL content of OH and CSH was 6.1% and 19.4%, respectively, and very little (15%) of the ADL disappeared during either in situ or in vivo fermentation. Much of the p-coumaric and ferulic acid of OH, associated with the cell wall matrix as lignin-carbohydrate and phenolic-carbohydrate complexes, was recovered in the fermented fractions. Data are interpreted to indicate that lignin encrustation and cellulose crystallinity are factors affecting CSH fermentation. Lignin encrustation and the presence of lignin-carbohydrate/phenolic-carbohydrate complexes are factors that inhibit OH fermentation.


Asunto(s)
Alimentación Animal/análisis , Aceite de Semillas de Algodón , Fibras de la Dieta/aislamiento & purificación , Grano Comestible , Animales , Benzaldehídos/análisis , Bovinos , Ácidos Cumáricos/análisis , Fibras de la Dieta/análisis , Digestión , Fermentación , Espectroscopía de Resonancia Magnética , Masculino , Monosacáridos/análisis , Propionatos
19.
Adv Exp Med Biol ; 302: 405-52, 1991.
Artículo en Inglés | MEDLINE | ID: mdl-1746343

RESUMEN

Water is the most important component of a food system, because it influences so many process variables, product characteristics, and stability attributes. Some of the most successful techniques used to probe the behavior of water in food systems are Nuclear Magnetic Resonance (NMR) spectroscopy and, more recently, pulsed-field gradient NMR and Magnetic Resonance Imaging (MRI). The purpose of this chapter is to review the theory underlying these techniques and to present several examples of how they have been applied to study water relations in foods.


Asunto(s)
Tecnología de Alimentos , Alimentos , Imagen por Resonancia Magnética , Espectroscopía de Resonancia Magnética , Agua , Carbohidratos/química , Fenómenos Químicos , Química Física , Proteínas/química , Agua/química
20.
Adv Exp Med Biol ; 302: 561-83, 1991.
Artículo en Inglés | MEDLINE | ID: mdl-1746350

RESUMEN

This paper reviews recent work on the interactions among solutes, polymers, and water in model food systems. Four possible combinations of ionic or non-ionic solutes and polymers are discussed in terms of their water sorption behavior. Comparisons between experimental values and values calculated by a mass balance equation are made. The salt-protein, sucrose-starch, and salt-starch combinations sorbed less water than that predicted by calculated sorption values. This was attributed to the inability of the interacted solutes to sorb their full complement of water. On the other hand, the sucrose-protein combination exhibited an increase in the amount of water sorbed over that calculated by the mass balance equation. This was attributed to the increased hydration of the protein component, due to an effect of the sucrose. One of the major factors involved in these solute-polymer interactions is the competition for water among the solutes and polymers. This competition, in turn, is greatly influenced by the "state" of the water associated with these components. Lastly, examples of how biological, chemical, and physico-chemical phenomena in foods are affected by these factors are also given. The phenomena discussed include mold germination, the Maillard reaction, ascorbic acid oxidation, protein functionality, starch gelatinization and retrogradation, and the complication of the order of mixing.


Asunto(s)
Alimentos , Polímeros/química , Soluciones , Agua/química , Carbohidratos/química , Fenómenos Químicos , Química Física , Proteínas/química , Sales (Química)/química , Almidón/química
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