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1.
PLoS One ; 18(5): e0285096, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37141189

RESUMEN

INTRODUCTION: Placental dysfunction can lead to perinatal hypoxic events including stillbirth. Unless there is overt severe fetal growth restriction, placental dysfunction is frequently not identified in (near) term pregnancy, particularly because fetal size is not necessarily small. This study aimed to evaluate, among (near) term births, the burden of hypoxia-related adverse perinatal outcomes reflected in an association with birth weight centiles as a proxy for placental function. MATERIAL AND METHOD: A nationwide 5-year cohort of the Dutch national birth registry (PeriNed) including 684,938 singleton pregnancies between 36+0 and 41+6 weeks of gestation. Diabetes, congenital anomalies, chromosomal abnormalities and non-cephalic presentations at delivery were excluded. The main outcome was antenatal mortality rate according to birthweight centiles and gestational age. Secondary outcomes included perinatal hypoxia-related outcomes, including perinatal death and neonatal morbidity, analyzed according to birthweight centiles. RESULTS: Between 2015 and 2019, 1,074 perinatal deaths (0.16%) occurred in the study population (n = 684,938), of which 727 (0.10%) antenatally. Of all antenatal- and perinatal deaths, 29.4% and 27.9% occurred in birthweights below the 10th centile. The incidence of perinatal hypoxia-related outcomes was highest in fetuses with lowest birthweight centiles (18.0%), falling gradually up to the 50th and 90th centile where the lowest rates of hypoxia-related outcomes (5.4%) were observed. CONCLUSION: Perinatal hypoxia-related events have the highest incidence in the lowest birthweight centiles but are identifiable throughout the entire spectrum. In fact, the majority of the adverse outcome burden in absolute numbers occurs in the group with a birthweight above the 10th centile. We hypothesize that in most cases these events are attributable to reduced placental function. Additional diagnostic modalities that indicate placental dysfunction at (near) term gestation throughout all birth weight centiles are eagerly wanted.


Asunto(s)
Muerte Perinatal , Mortalidad Perinatal , Recién Nacido , Embarazo , Femenino , Humanos , Peso al Nacer , Estudios de Cohortes , Recién Nacido Pequeño para la Edad Gestacional , Placenta , Mortinato/epidemiología , Edad Gestacional , Retardo del Crecimiento Fetal/epidemiología , Hipoxia
2.
Hum Reprod ; 37(12): 2808-2816, 2022 11 24.
Artículo en Inglés | MEDLINE | ID: mdl-36331493

RESUMEN

STUDY QUESTION: For couples with unexplained subfertility and a poor prognosis for natural conception, is 6 months expectant management (EM) inferior to IUI with ovarian stimulation (IUI-OS), in terms of live births? SUMMARY ANSWER: In couples with unexplained subfertility and a poor prognosis for natural conception, 6 months of EM is inferior compared to IUI-OS in terms of live births. WHAT IS KNOWN ALREADY: Couples with unexplained subfertility and a poor prognosis are often treated with IUI-OS. In couples with unexplained subfertility and a relatively good prognosis for natural conception (>30% in 12 months), IUI-OS does not increase the live birth rate as compared to 6 months of EM. However, in couples with a poor prognosis for natural conception (<30% in 12 months), the effectiveness of IUI-OS is uncertain. STUDY DESIGN, SIZE, DURATION: We performed a non-inferiority multicentre randomized controlled trial within the infrastructure of the Dutch Consortium for Healthcare Evaluation and Research in Obstetrics and Gynaecology. We intended to include 1091 couples within 3 years. The couples were allocated in a 1:1 ratio to 6 months EM or 6 months IUI-OS with either clomiphene citrate or gonadotrophins. PARTICIPANTS/MATERIALS, SETTING, METHODS: We studied heterosexual couples with unexplained subfertility and a poor prognosis for natural conception (<30% in 12 months). The primary outcome was ongoing pregnancy leading to a live birth. Non-inferiority would be shown if the lower limit of the one-sided 90% risk difference (RD) CI was less than minus 7% compared to an expected live birth rate of 30% following IUI-OS. We calculated RD, relative risks (RRs) with 90% CI and a corresponding hazard rate for live birth over time based on intention-to-treat and per-protocol (PP) analysis. MAIN RESULTS AND THE ROLE OF CHANCE: Between October 2016 and September 2020, we allocated 92 couples to EM and 86 to IUI-OS. The trial was halted pre-maturely owing to slow inclusion. Mean female age was 34 years, median duration of subfertility was 21 months. Couples allocated to EM had a lower live birth rate than couples allocated to IUI-OS (12/92 (13%) in the EM group versus 28/86 (33%) in the IUI-OS group; RR 0.40 90% CI 0.24 to 0.67). This corresponds to an absolute RD of minus 20%; 90% CI: -30% to -9%. The hazard ratio for live birth over time was 0.36 (95% CI 0.18 to 0.70). In the PP analysis, live births rates were 8 of 70 women (11%) in the EM group versus 26 of 73 women (36%) in the IUI-OS group (RR 0.32, 90% CI 0.18 to 0.59; RD -24%, 90% CI -36% to -13%) in line with inferiority of EM. LIMITATIONS, REASONS FOR CAUTION: Our trial did not reach the planned sample size, therefore the results are limited by the number of participants. WIDER IMPLICATIONS OF THE FINDINGS: This study confirms the results of a previous trial that in couples with unexplained subfertility and a poor prognosis for natural conception, EM is inferior to IUI-OS. STUDY FUNDING/COMPETING INTEREST(S): The trial was supported by a grant of the SEENEZ healthcare initiative. The subsidizing parties were The Dutch Organisation for Health Research and Development (ZonMW 837004023, www.zonmw.nl) and the umbrella organization of 10 health insurers in The Netherlands. E.R.G. receives personal fees from Titus Health care outside the submitted work. M.G. declares unrestricted research and educational grants from Guerbet, Merck and Ferring not related to the presented work, paid to their institution VU medical centre. A.B.H. reports receiving travel and speakers fees from Nordic Pharma and Merck and he is member of the Nordic Pharma ANGEL group and of the Safety Monitoring Board of Womed. C.B.L. reports speakers fee from Inmed and Yingming, and his department receives research grants from Ferring, Merck and Guerbet paid to VU medical centre. B.W.J.M. is supported by a NHMRC Investigator grant (GNT1176437) and reports consultancy for ObsEva and Merck. M.v.W. received a grant from the Netherlands Organisation for Health Research and Development ZonMW (80-8520098-91072). F.M. received two grants from the Netherlands Organisation for Health Research and Development ZonMW (NTR 5599 and NTR 6590). The other authors report no competing interest. TRIAL REGISTRATION NUMBER: Dutch Trial register NL5455 (NTR5599). TRIAL REGISTRATION DATE: 18 December 2015. DATE OF FIRST PATIENT'S ENROLMENT: 26 January 2017.


Asunto(s)
Infertilidad , Espera Vigilante , Embarazo , Masculino , Femenino , Humanos , Adulto , Índice de Embarazo , Infertilidad/terapia , Inducción de la Ovulación/métodos , Inseminación Artificial/métodos , Pronóstico
3.
Hum Reprod Update ; 28(5): 733-746, 2022 08 25.
Artículo en Inglés | MEDLINE | ID: mdl-35587030

RESUMEN

BACKGROUND: Intrauterine insemination with ovarian stimulation (IUI-OS) is a first-line treatment for unexplained infertility. Gonadotrophins, letrozole and clomiphene citrate (CC) are commonly used agents during IUI-OS and have been compared in multiple aggregate data meta-analyses, with substantial heterogeneity and no analysis on time-to-event outcomes. Individual participant data meta-analysis (IPD-MA) is considered the gold standard for evidence synthesis as it can offset inadequate reporting of individual studies by obtaining the IPD, and allows analyses on treatment-covariate interactions to identify couples who benefit most from a particular treatment. OBJECTIVE AND RATIONALE: We performed this IPD-MA to compare the effectiveness and safety of ovarian stimulation with gonadotrophins, letrozole and CC and to explore treatment-covariate interactions for important baseline characteristics in couples undergoing IUI. SEARCH METHODS: We searched electronic databases including MEDLINE, EMBASE, CENTRAL, CINAHL, and PsycINFO from their inception to 28 June 2021. We included randomized controlled trials (RCTs) comparing IUI-OS with gonadotrophins, letrozole and CC among couples with unexplained infertility. We contacted the authors of eligible RCTs to share the IPD and established the IUI IPD-MA Collaboration. The primary effectiveness outcome was live birth and the primary safety outcome was multiple pregnancy. Secondary outcomes were other reproductive outcomes, including time to conception leading to live birth. We performed a one-stage random effects IPD-MA. OUTCOMES: Seven of 22 (31.8%) eligible RCTs provided IPD of 2495 couples (62.4% of the 3997 couples participating in 22 RCTs), of which 2411 had unexplained infertility and were included in this IPD-MA. Six RCTs (n = 1511) compared gonadotrophins with CC, and one (n = 900) compared gonadotrophins, letrozole and CC. Moderate-certainty evidence showed that gonadotrophins increased the live birth rate compared to CC (6 RCTs, 2058 women, RR 1.30, 95% CI 1.12-1.51, I2 = 26%). Low-certainty evidence showed that gonadotrophins may also increase the multiple pregnancy rate compared to CC (6 RCTs, 2058 women, RR 2.17, 95% CI 1.33-3.54, I2 = 69%). Heterogeneity on multiple pregnancy could be explained by differences in gonadotrophin starting dose and choice of cancellation criteria. Post-hoc sensitivity analysis on RCTs with a low starting dose of gonadotrophins (≤75 IU) confirmed increased live birth rates compared to CC (5 RCTs, 1457 women, RR 1.26, 95% CI 1.05-1.51), but analysis on only RCTs with stricter cancellation criteria showed inconclusive evidence on live birth (4 RCTs, 1238 women, RR 1.15, 95% CI 0.94-1.41). For multiple pregnancy, both sensitivity analyses showed inconclusive findings between gonadotrophins and CC (RR 0.94, 95% CI 0.45-1.96; RR 0.81, 95% CI 0.32-2.03, respectively). Moderate certainty evidence showed that gonadotrophins reduced the time to conception leading to a live birth when compared to CC (6 RCTs, 2058 women, HR 1.37, 95% CI 1.15-1.63, I2 = 22%). No strong evidence on the treatment-covariate (female age, BMI or primary versus secondary infertility) interactions was found. WIDER IMPLICATIONS: In couples with unexplained infertility undergoing IUI-OS, gonadotrophins increased the chance of a live birth and reduced the time to conception compared to CC, at the cost of a higher multiple pregnancy rate, when not differentiating strategies on cancellation criteria or the starting dose. The treatment effects did not seem to differ in women of different age, BMI or primary versus secondary infertility. In a modern practice where a lower starting dose and stricter cancellation criteria are in place, effectiveness and safety of different agents seem both acceptable, and therefore intervention availability, cost and patients' preferences should factor in the clinical decision-making. As the evidence for comparisons to letrozole is based on one RCT providing IPD, further RCTs comparing letrozole and other interventions for unexplained infertility are needed.


Asunto(s)
Infertilidad Femenina , Infertilidad , Clomifeno/uso terapéutico , Femenino , Fármacos para la Fertilidad Femenina/uso terapéutico , Gonadotropinas/uso terapéutico , Humanos , Infertilidad/terapia , Infertilidad Femenina/terapia , Inseminación , Letrozol/uso terapéutico , Nacimiento Vivo , Inducción de la Ovulación , Embarazo , Índice de Embarazo
4.
Food Res Int ; 150(Pt A): 110697, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34865745

RESUMEN

Phenolic composition of young red wines has been shown to play an important role in their ageing potential. Therefore, the modulation of phenolic extraction during maceration may influence the subsequent phenolic evolution of these wines. The present work aimed to evaluate the impact of three different maceration times on the phenolic levels and evolution observed over time, using spectrophotometric and chromatography methods, and the effect on the aroma, taste, and mouthfeel sensory properties using Projective Mapping. Additionally, grape cell wall deconstruction was monitored during the extended maceration phase by GC-MS and Comprehensive Comprehensive Microarray Polymer Profiling (CoMPP). Our findings demonstrated that longer maceration times did not always correspond to an increase in wine phenolic concentration, although the level of complexity of these molecules seemed to be higher. Additionally, continuous depectination and possible solubilisation of the pectin is observed during the extended maceration which may be influencing the sensory perception of these wines. Maceration time was also shown to influence the evolution of the polymeric fraction and sensory perception of the wines.


Asunto(s)
Vitis , Vino , Bebidas Alcohólicas , Odorantes/análisis , Gusto , Vino/análisis
5.
Hum Reprod ; 36(3): 817-825, 2021 02 18.
Artículo en Inglés | MEDLINE | ID: mdl-33347597

RESUMEN

STUDY QUESTION: Does assisted reproduction, such as ovarian stimulation and/or laboratory procedures, have impact on perinatal outcomes of singleton live births compared to natural conception in couples with unexplained subfertility? SUMMARY ANSWER: Compared to natural conception, singletons born after intrauterine insemination with ovarian stimulation (IUI-OS) had a lower birthweight, while singletons born after IVF had comparable birthweights, in couples with unexplained subfertility. WHAT IS KNOWN ALREADY: Singletons conceived by assisted reproduction have different perinatal outcomes such as low birthweight and a higher risk of premature birth than naturally conceived singletons. This might be due to the assisted reproduction, such as laboratory procedures or the ovarian stimulation, or to an intrinsic factor in couples with subfertility. STUDY DESIGN, SIZE, DURATION: We performed a prospective cohort study using the follow-up data of two randomized clinical trials performed in couples with unexplained subfertility. We evaluated perinatal outcomes of 472 live birth singletons conceived after assisted reproduction or after natural conception within the time horizon of the studies. PARTICIPANTS/MATERIALS, SETTING, METHODS: To assess the possible impact of ovarian stimulation we compared the singletons conceived after IUI with FSH or clomiphene citrate (CC) and IVF in a modified natural cycle (IVF-MNC) or standard IVF with single embryo transfer (IVF-SET) to naturally conceived singletons in the same cohorts. To further look into the possible effect of the laboratory procedures, we put both IUI and IVF groups together into IUI-OS and IVF and compared both to singletons born after natural conception. We only included singletons conceived after fresh embryo transfers. The main outcome was birthweight presented as absolute weight in grams and gestational age- and gender-adjusted percentiles. We calculated differences in birthweight using regression analyses adjusted for maternal age, BMI, smoking, parity, duration of subfertility and child gender. MAIN RESULTS AND THE ROLE OF CHANCE: In total, there were 472 live birth singletons. Of the 472 singleton pregnancies, 209 were conceived after IUI-OS (136 with FSH and 73 with CC as ovarian stimulation), 138 after IVF (50 after IVF-MNC and 88 after IVF-SET) and 125 were conceived naturally.Singletons conceived following IUI-FSH and IUI-CC both had lower birthweights compared to naturally conceived singletons (adjusted difference IUI-FSH -156.3 g, 95% CI -287.9 to -24.7; IUI-CC -160.3 g, 95% CI -316.7 to -3.8). When we compared IVF-MNC and IVF-SET to naturally conceived singletons, no significant difference was found (adjusted difference IVF-MNC 75.8 g, 95% CI -102.0 to 253.7; IVF-SET -10.6 g, 95% CI -159.2 to 138.1). The mean birthweight percentile was only significantly lower in the IUI-FSH group (-7.0 percentile, 95% CI -13.9 to -0.2). The IUI-CC and IVF-SET group had a lower mean percentile and the IVF-MNC group a higher mean percentile, but these groups were not significant different compared to the naturally conceived group (IUI-CC -5.1 percentile, 95% CI -13.3 to 3.0; IVF-MNC 4.4 percentile, 95% CI -4.9 to 13.6; IVF-SET -1.3 percentile, 95% CI -9.1 to 6.4).Looking at the laboratory process that took place, singletons conceived following IUI-OS had lower birthweights than naturally conceived singletons (adjusted difference -157.7 g, 95% CI -277.4 to -38.0). The IVF group had comparable birthweights with the naturally conceived group (adjusted difference 20.9 g, 95% CI -110.8 to 152.6). The mean birthweight percentile was significantly lower in the IUI-OS group compared to the natural group (-6.4 percentile, 95% CI -12.6 to -0.1). The IVF group was comparable (0.7 percentile, 95% CI -6.1 to 7.6). LIMITATIONS, REASONS FOR CAUTION: The results are limited by the number of cases. The data were collected prospectively alongside the randomized controlled trials, but analyzed as treated. WIDER IMPLICATIONS OF THE FINDINGS: Our data suggest IUI in a stimulated cycle may have a negative impact on the birthweight of the child and possibly on pre-eclampsia. Further research should look into the effect of different methods of ovarian stimulation on placenta pathology and pre-eclampsia in couples with unexplained subfertility using naturally conceived singletons in the unexplained population as a reference. STUDY FUNDING/COMPETING INTEREST(S): Both initial trials were supported by a grant from ZonMW, the Dutch Organization for Health Research and Development (INeS 120620027, SUPER 80-83600-98-10192). The INeS study also had a grant from Zorgverzekeraars Nederland, the Dutch association of healthcare insurers (09-003). B.W.J.M. is supported by an NHMRC investigator Grant (GNT1176437) and reports consultancy for ObsEva, Merck Merck KGaA, Guerbet and iGenomix, outside the submitted work. A.H. reports grants from Ferring Pharmaceutical company (the Netherlands), outside the submitted work. F.J.M.B. receives monetary compensation as a member of the external advisory board for Merck Serono (the Netherlands), Ferring Pharmaceutics BV (the Netherlands) and Gedeon Richter (Belgium), he receives personal fees from educational activities for Ferring BV (the Netherlands) and for advisory and consultancy work for Roche and he receives research support grants from Merck Serono and Ferring Pharmaceutics BV, outside the submitted work. The remaining authors have nothing to disclose. TRIAL REGISTRATION NUMBER: INeS study Trial NL915 (NTR939); SUPER Trial NL3895 (NTR4057).


Asunto(s)
Fertilización In Vitro , Infertilidad , Bélgica , Peso al Nacer , Niño , Femenino , Estudios de Seguimiento , Humanos , Infertilidad/etiología , Infertilidad/terapia , Masculino , Países Bajos , Inducción de la Ovulación/efectos adversos , Embarazo , Índice de Embarazo , Estudios Prospectivos , Ensayos Clínicos Controlados Aleatorios como Asunto
6.
Food Chem ; 278: 26-35, 2019 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-30583371

RESUMEN

This study evaluated the relationship between cell wall breakdown, from Shiraz grapes harvested at three different ripeness levels and the colour and phenolics extracted during alcoholic fermentation into wines. Phenolic differences between the ripeness treatments were minimal after » of the fermentation was completed. However, colour and phenolic content were significantly higher in finished wines made from 25°Brix grapes compared to those from 21°Brix and 23°Brix. Levels of grape cell wall polysaccharide deconstruction during fermentation was a determining correlative factor in relation to phenolic extractability. In this context, the de-pectination observed during ripening was found to enhance this deconstruction or "opening-up" of the grape pomace during fermentation, thus increasing the differential extraction of specific polyphenols, especially polymeric polyphenols, into the wines. Additionally, the degree of cell wall deconstruction seemed to play a role in the possible retention and extraction of specific grape proanthocyanidins, depending on their nature and polymer length.


Asunto(s)
Pared Celular/metabolismo , Fenoles/análisis , Polisacáridos/química , Vitis/química , Vino/análisis , Cromatografía Líquida de Alta Presión , Color , Frutas/química , Frutas/metabolismo , Cromatografía de Gases y Espectrometría de Masas , Monosacáridos/análisis , Análisis de Componente Principal , Proantocianidinas/análisis , Espectrofotometría , Vitis/metabolismo
7.
Food Chem ; 278: 36-46, 2019 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-30583384

RESUMEN

Phenolic compounds play an important role in colour stability and sensory properties of red wine. This study evaluated berry skin cell wall composition and how this influences grape and wine phenolics at different ripeness levels (21°Brix, 23°Brix, and 25°Brix) over two consecutive vintages. The vintage effect was highly significant, especially in the pectin fraction of the grape cell walls and affected the concentrations of certain phenolics extracted. The climatic variance between the seasons might have influenced the differences observed in the grape cell wall compositions. Firstly, a higher grape and wine phenolic content, especially in polymeric phenols, was found in 2015 wines. Additionally, grape berry cell walls, especially at the earliest stages of ripening, were found to be more intact in 2015 than in 2016. Thus, a possible relationship was found between the degree of berry intactness, especially for pectin-rich components, and the corresponding phenolic extractability during the winemaking.


Asunto(s)
Pared Celular/metabolismo , Fenoles/análisis , Polisacáridos/química , Vitis/química , Vino/análisis , Pared Celular/química , Cromatografía Líquida de Alta Presión , Color , Frutas/química , Frutas/metabolismo , Cromatografía de Gases y Espectrometría de Masas , Monosacáridos/análisis , Análisis de Componente Principal , Vitis/metabolismo
8.
Annu Int Conf IEEE Eng Med Biol Soc ; 2018: 2993-2996, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30441027

RESUMEN

This paper presents the design of an 800 MHz VCO for both free-running and injection locked operation in a novel low power transmitter with wireless frequency reference, operating in the MICS band (402-405 MHz). The transmitter employs simultaneous tuning and locking, to set the desired channel with a minimal injected power. The VCO is designed and fabricated in a 0.13 $\mu \mathrm{m}$ SiGe BiCMOS process and has a core area of 0.5 $\mathrm{m}\mathrm{m}^{2}$. The measurement of the free-running VCO shows -107 dBc/Hz phase noise at 300 kHz frequency offset. If locked to an external frequency reference the VCO shows 118 dBc/Hz phase noise at 300 KHz offset, while consuming 3 mA from a 1.2 V supply (3.6 mW). When the VCO is tuned during the locking, 20 dBm of reference power is required to enable operation in the whole MICS band. The measured phase noise of the free-running VCO ensures reliable calibration of the proposed transmitter and the locked VCO satisfies all requirements of an implantable device using MICS band data transmission. Therefore, this VCO presents a key building block of an injection locked, frequency agile, implantable transmitter for the MICS band.


Asunto(s)
Prótesis e Implantes , Calibración , Diseño de Equipo
9.
Mol Pharmacol ; 93(4): 344-354, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29371233

RESUMEN

Angiotensin-converting enzyme (ACE) plays a central role in the renin-angiotensin system (RAS), which is primarily responsible for blood pressure homeostasis. Studies have shown that ACE inhibitors yield cardiovascular benefits that cannot be entirely attributed to the inhibition of ACE catalytic activity. It is possible that these benefits are due to interactions between ACE and RAS receptors that mediate the protective arm of the RAS, such as angiotensin II receptor type 2 (AT2R) and the receptor MAS. Therefore, in this study, we investigated the molecular interactions of ACE, including ACE homodimerization and heterodimerization with AT2R and MAS, respectively. Molecular interactions were assessed by fluorescence resonance energy transfer and bimolecular fluorescence complementation in human embryonic kidney 293 cells and Chinese hamster ovary-K1 cells transfected with vectors encoding fluorophore-tagged proteins. The specificity of dimerization was verified by competition experiments using untagged proteins. These techniques were used to study several potential requirements for the germinal isoform of angiotensin-converting enzyme expressed in the testes (tACE) dimerization as well as the effect of ACE inhibitors on both somatic isoforms of angiotensin-converting enzyme expressed in the testes (sACE) and tACE dimerization. We demonstrated constitutive homodimerization of sACE and of both of its domains separately, as well as heterodimerization of both sACE and tACE with AT2R, but not MAS. In addition, we investigated both soluble sACE and the sACE N domain using size-exclusion chromatography-coupled small-angle X-ray scattering and we observed dimers in solution for both forms of the enzyme. Our results suggest that ACE homo- and heterodimerization does occur under physiologic conditions.


Asunto(s)
Peptidil-Dipeptidasa A/química , Peptidil-Dipeptidasa A/metabolismo , Multimerización de Proteína/fisiología , Animales , Células CHO , Membrana Celular/metabolismo , Cricetinae , Cricetulus , Cristalización , Células HEK293 , Humanos , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína
10.
Food Res Int ; 98: 79-86, 2017 08.
Artículo en Inglés | MEDLINE | ID: mdl-28610735

RESUMEN

Elemental sulfur is a fungicide traditionally used to control Powdery Mildew in the production of grapes. The presence of sulfur residues in grape juice has been associated with increased production of hydrogen sulfide during fermentation, which could take part in the formation of the varietal thiol 3-mercaptohexanol. This work examines whether elemental sulfur additions to Sauvignon blanc juice can increase the levels of sought-after varietal thiols. Initial trials were performed in South Africa and indicated a positive impact of sulfur on the levels of thiols. Further experiments were then carried out with New Zealand Sauvignon blanc and confirmed a positive relationship between elemental sulfur additions and wine varietal thiols. The formation of hydrogen sulfide was observed when the addition of elemental sulfur was made to clarified juice, along with an increase in further reductive sulfur compounds. When the addition of sulfur was made to pressed juice, prior to clarification, the production of reductive sulfur compounds was drastically decreased. Some mechanistic considerations are also presented, involving the reduction of sulfur to hydrogen sulfide prior to fermentation.


Asunto(s)
Manipulación de Alimentos , Frutas , Hexanoles/análisis , Compuestos de Sulfhidrilo/análisis , Azufre , Vitis , Vino/análisis , Fermentación , Humanos , Sulfuro de Hidrógeno , Nueva Zelanda , Sudáfrica , Especificidad de la Especie , Vitis/clasificación
11.
J Agric Food Chem ; 64(42): 7979-7993, 2016 Oct 26.
Artículo en Inglés | MEDLINE | ID: mdl-27748118

RESUMEN

The effect of repetitive controlled oxidation on the chemical and sensory composition of a fresh and fruity style Sauvignon blanc wine was investigated. Chemical analyses were conducted together with extensive sensory profiling. A decrease in volatile thiols responsible for the fruity nuances and an increase in oxidation-related compounds, such as acetaldehyde, during the course of the oxidation was observed. The wine evolved from a fresh and fruity one to one with slight oxidation and then developed extreme oxidative characteristics. The control samples (no oxygen added) developed a "cooked" character that could indicate the formation of "reductive" compounds in these wines. Conversely, the wines that received a single dose of oxygen did not develop this flavor and were perceived to be fresher and fruitier than the control samples. The color of the wine evolved before the disappearance of the pleasant aroma.

12.
Nucl Instrum Methods Phys Res A ; 784: 531-537, 2015 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-25937684

RESUMEN

We are developing room temperature compound semiconductor detectors for applications in energy-resolved high-flux single x-ray photon-counting spectral computed tomography (CT), including functional imaging with nanoparticle contrast agents for medical applications and non destructive testing (NDT) for security applications. Energy-resolved photon-counting can provide reduced patient dose through optimal energy weighting for a particular imaging task in CT, functional contrast enhancement through spectroscopic imaging of metal nanoparticles in CT, and compositional analysis through multiple basis function material decomposition in CT and NDT. These applications produce high input count rates from an x-ray generator delivered to the detector. Therefore, in order to achieve energy-resolved single photon counting in these applications, a high output count rate (OCR) for an energy-dispersive detector must be achieved at the required spatial resolution and across the required dynamic range for the application. The required performance in terms of the OCR, spatial resolution, and dynamic range must be obtained with sufficient field of view (FOV) for the application thus requiring the tiling of pixel arrays and scanning techniques. Room temperature cadmium telluride (CdTe) and cadmium zinc telluride (CdZnTe) compound semiconductors, operating as direct conversion x-ray sensors, can provide the required speed when connected to application specific integrated circuits (ASICs) operating at fast peaking times with multiple fixed thresholds per pixel provided the sensors are designed for rapid signal formation across the x-ray energy ranges of the application at the required energy and spatial resolutions, and at a sufficiently high detective quantum efficiency (DQE). We have developed high-flux energy-resolved photon-counting x-ray imaging array sensors using pixellated CdTe and CdZnTe semiconductors optimized for clinical CT and security NDT. We have also fabricated high-flux ASICs with a two dimensional (2D) array of inputs for readout from the sensors. The sensors are guard ring free and have a 2D array of pixels and can be tiled in 2D while preserving pixel pitch. The 2D ASICs have four energy bins with a linear energy response across sufficient dynamic range for clinical CT and some NDT applications. The ASICs can also be tiled in 2D and are designed to fit within the active area of the sensors. We have measured several important performance parameters including; the output count rate (OCR) in excess of 20 million counts per second per square mm with a minimum loss of counts due to pulse pile-up, an energy resolution of 7 keV full width at half maximum (FWHM) across the entire dynamic range, and a noise floor about 20keV. This is achieved by directly interconnecting the ASIC inputs to the pixels of the CdZnTe sensors incurring very little input capacitance to the ASICs. We present measurements of the performance of the CdTe and CdZnTe sensors including the OCR, FWHM energy resolution, noise floor, as well as the temporal stability and uniformity under the rapidly varying high flux expected in CT and NDT applications.

13.
J Agric Food Chem ; 63(4): 1088-1098, 2015 Feb 04.
Artículo en Inglés | MEDLINE | ID: mdl-25591104

RESUMEN

The validation of ultraviolet-visible (UV-vis) spectroscopy combined with partial least-squares (PLS) regression to quantify red wine tannins is reported. The methylcellulose precipitable (MCP) tannin assay and the bovine serum albumin (BSA) tannin assay were used as reference methods. To take the high variability of wine tannins into account when the calibration models were built, a diverse data set was collected from samples of South African red wines that consisted of 18 different cultivars, from regions spanning the wine grape-growing areas of South Africa with their various sites, climates, and soils, ranging in vintage from 2000 to 2012. A total of 240 wine samples were analyzed, and these were divided into a calibration set (n = 120) and a validation set (n = 120) to evaluate the predictive ability of the models. To test the robustness of the PLS calibration models, the predictive ability of the classifying variables cultivar, vintage year, and experimental versus commercial wines was also tested. In general, the statistics obtained when BSA was used as a reference method were slightly better than those obtained with MCP. Despite this, the MCP tannin assay should also be considered as a valid reference method for developing PLS calibrations. The best calibration statistics for the prediction of new samples were coefficient of correlation (R2val) = 0.89, root mean standard error of prediction (RMSEP) = 0.16, and residual predictive deviation (RPD) = 3.49 for MCP and R2val = 0.93, RMSEP = 0.08, and RPD = 4.07 for BSA, when only the UV region (260-310 nm) was selected, which also led to a faster analysis time. In addition, a difference in the results obtained when the predictive ability of the classifying variables vintage, cultivar, or commercial versus experimental wines was studied suggests that tannin composition is highly affected by many factors. This study also discusses the correlations in tannin values between the methylcellulose and protein precipitation methods.

14.
Food Chem ; 169: 180-6, 2015 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-25236214

RESUMEN

Sotolon has been reported to play an important role in the atypical ageing and aroma character of many wines. A number of analytical techniques for sotolon analysis in wine have been reported, but these often require extensive sample preparation. In this work we report a HPLC-UV method and a novel UPLC-MS method to determine sotolon concentrations in white wines with little sample preparation applied for the first time for the evaluation of sotolon levels in South African wines. The validation showed that the instrumental methods had good accuracy, repeatability and linearity, but the UPLC-MS method proved more sensitive. For both methods, quantification limits were lower than the sotolon odour threshold in wine (10µg/L), 0.86µg/L and 0.013µg/L, for HPLC-UV and UPLC-MS methods, respectively. Sotolon levels in 65 South African white wines were often found to be lower than the reported odour threshold, with the highest concentration being 9.11µg/L. However, for low levels (<1µg/L), unknown interferences in certain wines led to sotolon not being quantified with the HPLC-UV method, which made the UPLC-MS method more suitable.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Furanos/análisis , Vino/análisis , Cromatografía Líquida de Alta Presión/instrumentación , Odorantes/análisis , Olfato
15.
Biochem Soc Trans ; 42(4): 1080-6, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25110006

RESUMEN

The biosynthesis and utilization of CoA (coenzyme A), the ubiquitous and essential acyl carrier in all organisms, have long been regarded as excellent targets for the development of new antimicrobial drugs. Moreover, bioinformatics and biochemical studies have highlighted significant differences between several of the bacterial enzyme targets and their human counterparts, indicating that selective inhibition of the former should be possible. Over the past decade, a large amount of structural and mechanistic data has been gathered on CoA metabolism and the CoA biosynthetic enzymes, and this has facilitated the discovery and development of several promising candidate antimicrobial agents. These compounds include both target-specific inhibitors, as well as CoA antimetabolite precursors that can reduce CoA levels and interfere with processes that are dependent on this cofactor. In the present mini-review we provide an overview of the most recent of these studies that, taken together, have also provided chemical validation of CoA biosynthesis and utilization as viable targets for antimicrobial drug development.


Asunto(s)
Antiinfecciosos , Coenzima A/biosíntesis , Inhibidores Enzimáticos
16.
Ophthalmologe ; 111(7): 638-43, 2014.
Artículo en Alemán | MEDLINE | ID: mdl-24062148

RESUMEN

BACKGROUND: The purpose of this study was to analyze if anterior chamber parameters are risk factors for the development of pigment dispersion syndrome (PDS) and/or for the conversion to pigmentary glaucoma (PG). PATIENTS AND METHODS: This study included a total of 63 eyes from 35 patients with PDS and PG and 65 eyes from 49 unaffected volunteers as the control group. The following parameters were measured by slit lamp optical coherence tomography (SL-OCT): anterior chamber volume (ACV) and depth (ACD), angle opening distance (AOD) and the trabecular iris space area (TISA) at 500 µm and 750 µm from the scleral spur. Comparisons between the following groups were performed: between the PDS/PG and the control group, between PDS and PG and between male and female patients. RESULTS: The results of ACV, ACD, AOD and TISA were significantly higher in PDS/PG patients when compared to the control group. There were no significant differences between PDS and PG. The gender-specific comparison also showed no significant differences. CONCLUSIONS: Significantly higher anterior chamber parameters are a possible risk factor for development of PDS; however, a higher risk of conversion to PG does not seem to correlate with increased anterior chamber parameters. The parameters of the anterior chamber are apparently not associated with the male predominance of PDS and PG.


Asunto(s)
Segmento Anterior del Ojo/patología , Síndrome de Exfoliación/complicaciones , Síndrome de Exfoliación/patología , Glaucoma de Ángulo Abierto/etiología , Glaucoma de Ángulo Abierto/patología , Lámpara de Hendidura , Tomografía de Coherencia Óptica/métodos , Adulto , Anciano , Femenino , Humanos , Masculino , Reproducibilidad de los Resultados , Factores de Riesgo , Sensibilidad y Especificidad , Factores Sexuales , Tomografía de Coherencia Óptica/instrumentación
17.
J Agric Food Chem ; 61(49): 11900-12, 2013 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-24070179

RESUMEN

The effect of prefermentative and postfermentative caffeic acid (CFA) addition, prefermentative cold maceration, and a simulation of the micro-oxygenation technique through acetaldehyde addition on the phenolic and color composition of Tempranillo wines was investigated. Cold soaking and dry ice addition were performed as prefermentative techniques. Wines were analyzed after the end of the malolactic fermentation and after 6 and 12 months' storage. The results showed an important effect in wines to which CFA had been added, suggesting intramolecular copigmentation reactions through direct interaction between anthocyanins and free phenolic acids, thereby increasing the acylated anthocyanin fraction with an increase in color stability. The higher concentration of total phenols and lower hue values in CFA-added wines also contributed to the stability of these compounds during storage. Prefermentative cold maceration was shown to be influenced by the vintage. Phenolic acids, the acylated anthocyanin fraction, and total phenolics showed higher values in CFA-added and acetaldehyde-added wines. No differences were found in color density between the control wines and both the prefermentative and postfermentative CFA-added wines. However, a higher anthocyanin polymeric fraction and higher acylated anthocyanins, phenolic acids, and total phenols were observed in the CFA-added wines. The implications of this for the color stability of Tempranillo are also discussed.


Asunto(s)
Ácidos Cafeicos/análisis , Aditivos Alimentarios/análisis , Manipulación de Alimentos/métodos , Fenoles/química , Vitis/química , Vino/análisis , Antocianinas/análisis , Color , Fermentación , Frutas/química , Frutas/microbiología , Saccharomyces cerevisiae/metabolismo , Vitis/microbiología , Vino/microbiología
18.
J Agric Food Chem ; 61(2): 269-77, 2013 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-23240621

RESUMEN

Glutathione is an important constituent of grapes, must, and wine. However, to date, no review has provided an integrated view of the role of this compound in wine-related systems. In this review, special emphasis is given to its occurrence in grapes, must, and wine and its role as an antioxidant in wine. The effect of glutathione on both desirable and undesirable aroma compounds is also outlined. Furthermore, the use of glutathione-enriched products in winemaking and the various analytical techniques for the quantification of glutathione in must and wine are discussed. Limitations in existing knowledge are also identified.


Asunto(s)
Antioxidantes/metabolismo , Calidad de los Alimentos , Glutatión/metabolismo , Vino/análisis , Antioxidantes/análisis , Bebidas/análisis , Bebidas/economía , Industria de Procesamiento de Alimentos/economía , Frutas/química , Frutas/metabolismo , Glutatión/análisis , Residuos Industriales/análisis , Residuos Industriales/economía , Oxidación-Reducción , Vitis/química , Vitis/metabolismo , Vino/economía
19.
Biochemistry ; 51(39): 7699-711, 2012 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-22954034

RESUMEN

Disruption of the unusual thiol-based redox homeostasis mechanisms in Staphylococcus aureus represents a unique opportunity to identify new metabolic processes and new targets for intervention. Targeting uncommon aspects of CoASH biosynthetic and redox functions in S. aureus, the antibiotic CJ-15,801 has recently been demonstrated to be an antimetabolite of the CoASH biosynthetic pathway in this organism; CoAS-mimetics containing α,ß-unsaturated sulfone and carboxyl moieties have also been exploited as irreversible inhibitors of S. aureus coenzyme A-disulfide reductase (SaCoADR). In this work we have determined the crystal structures of three of these covalent SaCoADR-inhibitor complexes, prepared by inactivation of wild-type enzyme during turnover. The structures reveal the covalent linkage between the active-site Cys43-S(γ) and C(ß) of the vinyl sulfone or carboxyl moiety. The full occupancy of two inhibitor molecules per enzyme dimer, together with kinetic analyses of the wild-type/C43S heterodimer, indicates that half-sites-reactivity is not a factor during normal catalytic turnover. Further, we provide the structures of SaCoADR active-site mutants; in particular, Tyr419'-OH plays dramatic roles in directing intramolecular reduction of the Cys43-SSCoA redox center, in the redox asymmetry observed for the two FAD per dimer in NADPH titrations, and in catalysis. The two conformations observed for the Ser43 side chain in the C43S mutant structure lend support to a conformational switch for Cys43-S(γ) during its catalytic Cys43-SSCoA/Cys43-SH redox cycle. Finally, the structures of the three inhibitor complexes provide a framework for design of more effective inhibitors with therapeutic potential against several major bacterial pathogens.


Asunto(s)
Antibacterianos/química , Antibacterianos/farmacología , Coenzima A/química , Coenzima A/farmacología , NADH NADPH Oxidorreductasas/antagonistas & inhibidores , Staphylococcus aureus/enzimología , Cristalografía por Rayos X , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Humanos , Simulación del Acoplamiento Molecular , Mutación , NADH NADPH Oxidorreductasas/química , NADH NADPH Oxidorreductasas/genética , NADH NADPH Oxidorreductasas/metabolismo , Oxidación-Reducción , Multimerización de Proteína , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/química , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/genética
20.
Transl Psychiatry ; 2: e119, 2012 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-22832964

RESUMEN

The identification and exploration of genetic loci that influence smoking behaviors have been conducted primarily in populations of the European ancestry. Here we report results of the first genome-wide association study meta-analysis of smoking behavior in African Americans in the Study of Tobacco in Minority Populations Genetics Consortium (n = 32,389). We identified one non-coding single-nucleotide polymorphism (SNP; rs2036527[A]) on chromosome 15q25.1 associated with smoking quantity (cigarettes per day), which exceeded genome-wide significance (ß = 0.040, s.e. = 0.007, P = 1.84 × 10(-8)). This variant is present in the 5'-distal enhancer region of the CHRNA5 gene and defines the primary index signal reported in studies of the European ancestry. No other SNP reached genome-wide significance for smoking initiation (SI, ever vs never smoking), age of SI, or smoking cessation (SC, former vs current smoking). Informative associations that approached genome-wide significance included three modestly correlated variants, at 15q25.1 within PSMA4, CHRNA5 and CHRNA3 for smoking quantity, which are associated with a second signal previously reported in studies in European ancestry populations, and a signal represented by three SNPs in the SPOCK2 gene on chr10q22.1. The association at 15q25.1 confirms this region as an important susceptibility locus for smoking quantity in men and women of African ancestry. Larger studies will be needed to validate the suggestive loci that did not reach genome-wide significance and further elucidate the contribution of genetic variation to disparities in cigarette consumption, SC and smoking-attributable disease between African Americans and European Americans.


Asunto(s)
Negro o Afroamericano/genética , Fumar/genética , Adulto , Anciano , Cromosomas Humanos Par 10/genética , Cromosomas Humanos Par 15/genética , Femenino , Sitios Genéticos/genética , Predisposición Genética a la Enfermedad/genética , Variación Genética/genética , Estudio de Asociación del Genoma Completo , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Proteínas del Tejido Nervioso/genética , Fenotipo , Polimorfismo de Nucleótido Simple/genética , Proteoglicanos/genética , Receptores Nicotínicos/genética , Estadística como Asunto
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