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1.
J Chem Phys ; 151(17): 174105, 2019 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-31703507

RESUMEN

The chiral Fe3O(NC5H5)3(O2CC6H5)6 molecular cation, with C3 symmetry, is composed of three six-fold coordinated spin-carrying Fe3+ cations that form a perfect equilateral triangle. Experimental reports demonstrating the spin-electric effect in this system also identify the presence of a magnetic uniaxis and suggest that this molecule may be a good candidate for an externally controllable molecular qubit. Here, we demonstrate, using standard density-functional methods, that the spin-electric behavior of this molecule could be even more interesting as there are energetically competitive reference states associated with both high and low local spins (S = 5/2 vs S = 1/2) on the Fe3+ ions. Each of these structures allow for spin-electric ground states. We find that qualitative differences in the broadening of the Fe(2s) and O(1s) core levels, shifts in the core-level energies, and the magnetic signatures of the single-spin anisotropy Hamiltonian may be used to confirm whether a transition between a high-spin manifold and a low spin manifold occurs.

2.
Analyst ; 140(17): 6079-88, 2015 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-26198701

RESUMEN

We present the characterisation and validation of multiplexed 4-terminal (4T) impedance measurements as a method for sensing the spatial location of cell aggregates within large three-dimensional (3D) gelatin scaffolds. The measurements were performed using an array of four rectangular chambers, each having eight platinum needle electrodes for parallel analysis. The electrode positions for current injection and voltage measurements were optimised by means of finite element simulations to maximise the sensitivity field distribution and spatial resolution. Eight different 4T combinations were experimentally tested in terms of the spatial sensitivity. The simulated sensitivity fields were validated using objects (phantoms) with different conductivity and size placed in different positions inside the chamber. This provided the detection limit (volume sensitivity) of 16.5%, i.e. the smallest detectable volume with respect to the size of the measurement chamber. Furthermore, the possibility for quick single frequency analysis was demonstrated by finding a common frequency of 250 kHz for all the presented electrode combinations. As final proof of concept, a high density of human hepatoblastoma (HepG2) cells were encapsulated in gelatin to form artificial 3D cell constructs and detected when placed in different positions inside large gelatin scaffolds. Taken together, these results open new perspectives for impedance-based sensing technologies for non-invasive monitoring in tissue engineering applications providing spatial information of constructs within biologically relevant 3D environments.


Asunto(s)
Impedancia Eléctrica , Ingeniería de Tejidos , Tomografía/métodos , Técnicas de Cultivo de Célula , Electrodos , Gelatina/química , Células Hep G2 , Humanos , Tomografía/instrumentación
3.
J Phys Condens Matter ; 36(40)2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-38941992

RESUMEN

Quantum anomalous Hall insulators are topologically characterized by non-zero integer Chern numbers, the sign of which depends on the direction of the exchange field that breaks time-reversal symmetry. This feature allows the manipulation of the conducting chiral edge states present at the interface of two magnetic domains with opposite magnetization and opposite Chern numbers. Motivated by this broad understanding, the present study investigates the quantum transport properties of a magnetizedBi2Se3topological insulator nanoribbon with a domain wall (DW) oriented either parallel or perpendicular to the transport direction. Employing an atomistic tight-binding model and a non-equilibrium Green's function formalism, we calculate the quantum conductance and explore the nature of the edge states. We elucidate the conditions leading to exact conductance quantization and identify the origin of deviations from this behavior. Our analysis shows that although the conductance is quantized in the presence of the horizontal DW, the quantization is absent in the perpendicular DW case. Furthermore, the investigation of the spin character of the edge modes confirms that the conductance in the horizontal DW configuration is spin polarized. This finding underscores the potential of our system as a simple three dimensional spin-filter device.

4.
Int J Legal Med ; 127(6): 1109-23, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23842669

RESUMEN

We have combined morphological, molecular, and chemical techniques in order to identify the plant and chemical composition of some last-generation smart drugs, present on the market under the following names: Jungle Mistic Incense, B-52, Blendz, and Kratom 10x. Micromorphological analyses of botanical fragments allowed identification of epidermal cells, stomata, trichomes, starch, crystals, and pollen. DNA barcoding was carried out by the plastidial gene rbcL and the spacer trnH-psbA as universal markers. The combination of morphological and molecular data revealed a mixture of plants from different families, including aromatic species, viz., Lamiaceae and Turneraceae. GC-MS and LC-MS analyses on ethanol or methanol extracts showed the presence of synthetic cannabinoids, including JWH-250 in Jungle, JWH-122 in B-52, and JWH-073 and JWH-018 in Blendz. In Kratom 10x, only the indole alkaloid mitragynine was detected. All the identified synthetic cannabinoids, apart from mitragynine, are under the restriction of law in Italy (TU 309/90). Synthetic cannabinoid crystals were also identified by scanning electron microscopy and energy dispersive X-ray spectroscopy, which also detected other foreign organic chemicals, probably preservatives or antimycotics. In Kratom only leaf fragments from Mitragyna speciosa, containing the alkaloid mitragynine, were found. In the remaining products, aromatic plant species have mainly the role of hiding synthetic cannabinoids, thus acting as a "green shuttle" rather than as real drugs. Such a multidisciplinary approach is proposed as a method for the identification of herbal blends of uncertain composition, which are widely marketed in "headshops" and on the Internet, and represent a serious hazard to public health.


Asunto(s)
Cannabinoides/análisis , Drogas de Diseño/análisis , Drogas Ilícitas/análisis , Plantas/química , Alcaloides de Triptamina Secologanina/análisis , ADN Intergénico/genética , ADN de Plantas/análisis , ADN de Plantas/genética , Cromatografía de Gases y Espectrometría de Masas , Medicina de Hierbas , Humanos , Italia , Microscopía Electrónica de Rastreo , Plantas/anatomía & histología , Plantas/genética , Ribulosa-Bifosfato Carboxilasa/genética , Espectrometría por Rayos X
5.
J Phys Condens Matter ; 34(12)2022 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-34915463

RESUMEN

We have performed electron transport and angle-resolved photo-emission spectroscopy (ARPES) measurements on single crystals of transition metal dipnictide TaAs2cleaved along the (2¯01) surface which has the lowest cleavage energy. A Fourier transform of the Shubnikov-de Haas oscillations shows four different peaks whose angular dependence was studied with respect to the angle between magnetic field and the [2¯01] direction. The results indicate elliptical shape of the Fermi surface cross-sections. Additionally, a mobility spectrum analysis was carried out, which also reveals at least four types of carriers contributing to the conductance (two kinds of electrons and two kinds of holes). ARPES spectra were taken on freshly cleaved (2¯01) surface and it was found that bulk states pockets at constant energy surface are elliptical, which confirms the magnetotransport angle dependent studies. First-principles calculations support the interpretation of the experimental results. The theoretical calculations better reproduce the ARPES data if the theoretical Fermi level (FL) is increased, which is due to a small n-doping of the samples. This shifts the FL closer to the Dirac point, allowing investigating the physics of the Dirac and Weyl points, making this compound a platform for the investigation of the Dirac and Weyl points in three-dimensional materials.

6.
Phys Rev Lett ; 106(1): 017202, 2011 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-21231770

RESUMEN

We determine the effective total spin J of local moments formed from acceptor states bound to Mn ions in GaAs by evaluating their magnetic Chern numbers. When individual Mn atoms are close to the sample surface, the total spin changes from J=1 to J=2, due to quenching of the acceptor orbital moment. For Mn pairs in bulk, the total J depends on pair orientation in the GaAs lattice and on the separation between the Mn atoms. We point out that Berry curvature variation as a function of local moment orientation can profoundly influence the quantum-spin dynamics of these magnetic entities.

7.
Phys Rev Lett ; 104(7): 073004, 2010 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-20366878

RESUMEN

We have investigated the hyperfine structure of the transition between the 5d{7}6s{2} {4}F{9/2}{e} ground state and the 5d{6}6s{2}6p {6}D{J}{o} excited state in the negative osmium ion by high-resolution collinear laser spectroscopy. This transition is unique because it is the only known electric-dipole transition in atomic anions and might be amenable to laser cooling. From the observed hyperfine structure in 187Os- and 189Os- the yet unknown total angular momentum of the bound excited state was found to be J=9/2. The hyperfine structure constants of the {4}F{9/2}{e} ground state and the {6}D{9/2}{o} excited state were determined experimentally and compared to multiconfiguration Dirac-Fock calculations. Using the knowledge of the ground and excited state angular momenta, the full energy level diagram of 192Os- in an external magnetic field was calculated, revealing possible laser cooling transitions.

8.
Phys Rev Lett ; 104(1): 017202, 2010 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-20366388

RESUMEN

We consider tunneling transport through a Mn12 molecular magnet using spin density functional theory. A tractable methodology for constructing many-body wave functions from Kohn-Sham orbitals allows for the determination of spin-dependent matrix elements for use in transport calculations. The tunneling conductance at finite bias is characterized by peaks representing transitions between spin multiplets, separated by an energy on the order of the magnetic anisotropy. The energy splitting of the spin multiplets and the spatial part of their many-body wave functions, describing the orbital degrees of freedom of the excess charge, strongly affect the electronic transport, and can lead to negative differential conductance.

9.
Res Vet Sci ; 118: 126-133, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29421481

RESUMEN

This study investigates the effects of linseed (rich in ɑ-linolenic acid (ALA)) and fish oil (rich in eicosapentaenoic (EPA) and docosahexaenoic acid (DHA)) supplementation on the insulin resistance of pregnant rabbits. Two months before insemination, the rabbits (15 animals/group) were fed different diets: commercial standard (group C), supplemented with 10% extruded linseed (group L), and 3% fish oil (group FO). The L group does showed both the highest feed intake before AI (P < 0.01) and the highest body weight (BW) throughout pregnancy (P < 0.001). The L does yielded less milk than the C does (P < 0.001); however, no differences were observed in either weight or size of litter at weaning. Regardless of diet, insulin concentrations and HOMA-IR values were higher during the first half of pregnancy (P < 0.001). Nevertheless, the L does showed higher mean insulin concentrations than FO rabbits (P < 0.01) and the lowest glucose clearance (P < 0.01) during pregnancy. On the other hand, pregnant FO rabbits showed the lowest glucose concentrations (P < 0.05) and the lowest Homeostasis model assessment values for insulin resistance (HOMA-IR, P < 0.05) as well as a faster restoration of baseline glucose levels following glucose load (P < 0.001). Before and during pregnancy, the BW of the rabbits was positively related to fasting sample- and tolerance test-derived indices of insulin resistance (P < 0.05) suggesting that a high pre-pregnancy BW predisposes to gestational insulin resistance. Linseed supplementation increased BW and predisposed to insulin resistance during pregnancy; whereas, fish oil improved insulin sensitivity without significant changes in BW.


Asunto(s)
Aceites de Pescado/administración & dosificación , Resistencia a la Insulina , Aceite de Linaza/administración & dosificación , Preñez/metabolismo , Animales , Dieta , Femenino , Lino , Embarazo , Conejos
10.
Nanoscale ; 9(6): 2129-2137, 2017 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-28120988

RESUMEN

(Ga,Mn)As having a wurtzite crystal structure was coherently grown by molecular beam epitaxy on the {1100} side facets of wurtzite (Ga,In)As nanowires and further encapsulated by (Ga,Al)As and low temperature GaAs. For the first time, a truly long-range ferromagnetic magnetic order is observed in non-planar (Ga,Mn)As, which is attributed to a more effective hole confinement in the shell containing Mn by the proper selection/choice of both the core and outer shell materials.

11.
Theriogenology ; 97: 73-77, 2017 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-28583611

RESUMEN

For the first time in literature this study describes the pregnancy-associated glycoprotein (PAG) profile of buffalo cows during gestation and the post-partum period using antiserum raised against PAG-molecules purified from buffalo placenta (AS#860). Ninety-eight buffalo cows, belonging to a buffalo herd subjected to a synchronization and artificial insemination (AI) program, were enrolled in this study. Blood samples were taken on days 0 (AI), 23, 25, 28, 30 and then biweekly until the end of pregnancy. Pregnancy was confirmed by ultrasonography on days 28 and 45, and by rectal palpation from day 60 onwards. Blood samples were suspended for the non-pregnant cows on day 45, while the blood of 20 buffaloes that had calved was tested every five days from the day of calving until day 50 post-calving. A cut-off value of 1.0 ng/mL was used in order to discriminate between pregnant and non-pregnant buffaloes. We used Linear Mixed models after Log(x+1) transformation to analyse the PAG concentrations. Fifty-two buffalo cows had become pregnant out of 98 synchronized (53%) and 46 remained non-pregnant (47%) as shown by ultrasonography and the PAG analysis. Significant differences (P < 0.001) in PAG concentrations were observed between the pregnant and non-pregnant buffaloes from day 23 as the PAG of the non-pregnant cows was always close to zero. Conversely, the PAG of the pregnant cows increased progressively from day AI until day 105 post-insemination and then stabilized until the end of pregnancy. Regarding pregnancy diagnosis, the sensitivity of PAG-RIA 860 system (ability of the test to correctly identify pregnant buffalo) ranged from 23% on day 23-98% on day 28 post AI; the specificity (ability to correctly identify non-pregnant buffaloes) was 100% throughout the sampling period. PAG progressively decreased from parturition to day 25 post-partum; from day 30 post-partum, the concentrations fell below 1 ng/mL and were close to 0 on the last day of observation (50 d post-partum). In conclusion, our results showed that RIA-860 is highly accurate for diagnosing pregnancy in buffaloes starting from day 28 of gestation. Furthermore, the rapid disappearance of PAG concentration after calving means that a cut-off limit in post-partum for detecting a new pregnancy is not required.


Asunto(s)
Búfalos/fisiología , Periodo Posparto/sangre , Proteínas Gestacionales/sangre , Preñez , Animales , Femenino , Embarazo , Preñez/sangre , Sensibilidad y Especificidad
12.
Theriogenology ; 89: 106-113, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-28043340

RESUMEN

This study investigates for the first time mRNA pregnancy-associated glycoprotein 2 (PAG-2) expression in blood cells during early pregnancy in water buffalo. The PAGs constitute a large family of glycoproteins expressed in the outer epithelial layer of the placenta in eutherian species. All PAGs are not concomitantly expressed throughout pregnancy; some of them are expressed in the earlier phases, whereas others appear later and are expressed over a shorter period. Twenty-one lactating buffaloes were analyzed-17 females were synchronized with PRID and artificially inseminated (AI), whereas four females were synchronized but not inseminated (control group). Blood was collected at Days 0, 18, 28, 40, and 75 from AI (AI = Day 0). Expression of PAG-2 mRNA in blood samples was measured with real-time polymerase chain reaction. Pregnancy diagnosis was performed on Day 28 (D28) and Day 40 (D40) after AI by ultrasonography (US) and by PAG-1 RIA method. The females diagnosed pregnant at D28 and confirmed pregnant at D40 were defined as D28(+)D40(+) group; the females diagnosed pregnant at D28 but not confirmed pregnant at D40 were defined as D28(+)D40(-) group; and the females that were diagnosed as nonpregnant on either days were defined as D28(-)D40(-) group. PAG-2 mRNA at Day 0 was not observed in any groups. The D28(+)D40(+) group showed the highest expression, starting on Day 18 and increasing progressively up to Day 75. PAG-2 mRNA was also expressed on Day 18 in both D28(+)D40(-) and D28(-)D40(-) groups, but their levels were lower than those of D28(+)D40(+) group and almost constant over time. PAG-2 mRNA was never detected in the control group. The significant difference in the expression of PAG-2 mRNA between the D28(+)D40(+) group and the D28(-)D40(-) group, starting from Day 18, suggests that these animals might have conceived, but have experienced early embryonic loss; therefore, the PAG-2 mRNA was still present in blood circulation although at lower levels, as found in the D28(+)D40(-) group. In conclusion, this study shows that PAG-2 mRNA can be detected in peripheral maternal blood cells earlier than circulating PAG-1 molecules and could be useful for studies on early pregnancy and embryonic mortality.


Asunto(s)
Ácido Aspártico Endopeptidasas/sangre , Búfalos/fisiología , Preñez/sangre , ARN Mensajero/análisis , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Animales , Ácido Aspártico Endopeptidasas/genética , Búfalos/sangre , Sincronización del Estro , Femenino , Inseminación Artificial , Placenta/metabolismo , Embarazo , Pruebas de Embarazo/veterinaria , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos
13.
Res Vet Sci ; 98: 7-12, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25499747

RESUMEN

This study examined the effects of food restriction during rabbit pregnancy on hormones and metabolites involved in energy homeostasis and metabolic programming. Pregnant does were assigned to four groups: the control group was fed a standard ration while the others received a restricted amount of food (30% restriction) during early (0-9 days), mid (9-18 days), and late (19-28 days) pregnancy. The pregnancy induced a coordinated range of adaptations to fulfil energy requirements of both mother and foetus, such as hyperleptinaemia and hyperinsulinaemia, reduced insulin sensitivity, increased cortisol and non-esterified fatty acid. Food restriction altered leptin, insulin, T3, non-esterified fatty acids and glucose concentrations depending on the gestational phase in which it was applied. Collectively, present data confirm that the endocrinology of pregnancy and the adaptive responses to energy deficit make the rabbit an ideal model for studying nutritional-related disorders and foetal programming of metabolic disease.


Asunto(s)
Dieta/veterinaria , Metabolismo Energético/fisiología , Homeostasis/fisiología , Hormonas/metabolismo , Desnutrición/veterinaria , Preñez/metabolismo , Efectos Tardíos de la Exposición Prenatal/veterinaria , Conejos/metabolismo , Fenómenos Fisiológicos Nutricionales de los Animales/fisiología , Animales , Ácidos Grasos no Esterificados/metabolismo , Femenino , Feto/fisiología , Glucosa/metabolismo , Insulina/metabolismo , Resistencia a la Insulina/fisiología , Leptina/metabolismo , Modelos Animales , Embarazo , Efectos Tardíos de la Exposición Prenatal/metabolismo
14.
Hypertension ; 23(2): 211-6, 1994 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8307631

RESUMEN

To assess the reproducibility of ambulatory blood pressure, we recorded 24-hour blood pressure twice 3 months apart in 508 hypertensive subjects participating in the HARVEST trial using a noninvasive technique. Blood pressure was measured every 10 minutes during the daytime and 30 minutes during the nighttime. Reproducibility was better for ambulatory than for office blood pressure. It was greater for 24-hour than for daytime blood pressure and lowest for nighttime blood pressure. The reproducibility of blood pressure variability (standard deviation) was poorer than that of the average values. A small but significant decrease in average daytime blood pressure (-0.8/-1.0 mm Hg) and virtually no change in nighttime blood pressure (+0.5/+0.1 mm Hg) were observed at repeat recording. Reducing the sampling rate by 50% caused only a small impairment of the reproducibility indexes of both the average values and variability. Blood pressure reduction was greater during the first and last hours of the recordings, indicating an effect of the hospital environment on the between-monitoring difference. Changes in body weight (-0.7 kg, P = .006, at repeat recording) were related to those of 24-hour diastolic blood pressure (P < .05). In conclusion, patient reaction to medical environment and changes of body weight seem to account for most of the change in 24-hour blood pressure that occurs over a 3-month period.


Asunto(s)
Determinación de la Presión Sanguínea , Adolescente , Adulto , Presión Sanguínea , Determinación de la Presión Sanguínea/métodos , Peso Corporal , Femenino , Humanos , Masculino , Persona de Mediana Edad , Monitoreo Fisiológico , Reproducibilidad de los Resultados
15.
Hypertension ; 27(5): 1039-45, 1996 May.
Artículo en Inglés | MEDLINE | ID: mdl-8621194

RESUMEN

We investigated the effects on the heart of hypertension due to the excess of aldosterone and suppression of the renin-angiotensin system caused by primary aldosteronism with M-mode echocardiography and transmitral Doppler flow velocity measurements. We studied 34 consecutive patients with primary aldosteronism and 34 with essential hypertension individually matched for age, gender, race, body mass index, blood pressure values, and duration of hypertension. The groups were similar in age, body mass index, blood pressure, and duration of hypertension. However, lower serum potassium levels (3.5 +/- 0.6 versus 4.1 +/- 0.2 mmol/L, P < .0001) and plasma renin activity (0.53 +/- 0.45 versus 1.82 +/- 1.59 ng Ang I x mL-1 x h-1, P < .0001) and higher plasma aldosterone levels (1107 +/- 774 versus 206 +/- 99 pmol/L, P < .0001), left ventricular wall thickness, and left ventricular mass index (112 +/- 4.7 versus 98 +/- 3.7 g/m2, P = .029) were found in patients with primary aldosteronism compared with those with essential hypertension. Similarly, the PQ interval was longer (173 +/- 20 versus 141 +/- 14 milliseconds, P < .001) in primary aldosteronism than in essential hypertension patients. Significantly more primary aldosteronism than essential hypertension patients had left ventricular hypertrophy or left ventricular concentric remodeling (50% versus 15%, chi 2 = 11.97, P = .007). Both the E wave flow velocity integral (1063 +/- 65 versus 1323 +/- 78, P = .013) and the E/A integral ratio (0.91 +/- 0.05 versus 1.25 +/- 0.08, P < .001) were lower, and atrial contribution to left ventricular filling was higher (53.3 +/- 1.5% versus 45.5 +/- 1.3% P < .001) in patients with primary aldosteronism compared with essential hypertension patients. After 1 year of follow-up, highly significant decreases of left ventricular wall thickness and mass were observed in patients treated with surgical excision of an aldosterone-producing tumor, but not in those with medical therapy. Thus, in patients with primary aldosteronism, the excess aldosterone with suppression of the renin-angiotensin system is associated with both increased left ventricular mass and significant changes of left ventricular diastolic filling. The former changes appear to be reversible on removal of the cause of excessive aldosterone production.


Asunto(s)
Cardiomegalia/diagnóstico por imagen , Cardiomegalia/fisiopatología , Hiperaldosteronismo/diagnóstico por imagen , Hiperaldosteronismo/fisiopatología , Hipertensión/diagnóstico por imagen , Hipertensión/fisiopatología , Función Ventricular Izquierda , Adulto , Velocidad del Flujo Sanguíneo , Ecocardiografía , Femenino , Estudios de Seguimiento , Ventrículos Cardíacos/patología , Humanos , Hiperaldosteronismo/terapia , Hipertensión/terapia , Masculino , Persona de Mediana Edad , Válvula Mitral/fisiopatología , Estudios Prospectivos , Reología
16.
Am J Med ; 103(3): 208-16, 1997 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9316553

RESUMEN

PURPOSE: This study was undertaken to investigate whether there is a relationship between the white-coat effect and the cardiovascular complications of hypertension. PATIENTS AND METHODS: In 1,013 consecutive borderline to severe hypertensive outpatients (889 men) with a mean age (+/-SE) of 33.6 +/- 0.5 years and a mean office blood pressure of 152.3 +/- 0.6/95.5 +/- 0.4 mm Hg, blood pressure was measured by noninvasive 24-hour ambulatory monitoring. Target organ damage was assessed by electrocardiogram, chest X-ray, echocardiography, and ophthalmoscopy. The degree of target organ damage and of left ventricular hypertrophy was assessed in the subjects divided according to the levels of their daytime blood pressure and the extent of their white-coat effect. RESULTS: The subjects with a high white-coat effect showed a greater degree of hypertensive complications than those with intermediate or a low white-coat effect. The significant association between the white-coat phenomenon and the hypertensive complications was confirmed by the results of stepwise regression analyses, where sex, age, duration of hypertension, and ambulatory blood pressure were added to the model. A two-way ANOVA showed that both ambulatory blood pressure and the white-coat effect were related to the degree of target organ damage and to left ventricular hypertrophy. Moreover, daytime blood pressure and the white-coat effect showed an interactive effect on hypertensive complications, as the influence of the white-coat effect on end organs increased with increasing levels of ambulatory blood pressure. CONCLUSIONS: The present results show that the white-coat effect is related to the degree of hypertensive complications and that this association is stronger in the subject with more severe hypertension.


Asunto(s)
Enfermedades Cardiovasculares/etiología , Hipertensión/psicología , Estrés Psicológico/complicaciones , Estrés Psicológico/fisiopatología , Adulto , Atención Ambulatoria , Presión Sanguínea , Enfermedades Cardiovasculares/fisiopatología , Enfermedades Cardiovasculares/psicología , Ecocardiografía , Electrocardiografía , Femenino , Humanos , Hipertensión/complicaciones , Hipertensión/fisiopatología , Masculino , Oftalmoscopía , Análisis de Regresión , Índice de Severidad de la Enfermedad
17.
J Hypertens ; 13(12 Pt 2): 1796-800, 1995 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8903654

RESUMEN

OBJECTIVE: To study the relationship of urinary albumin excretion to ambulatory blood pressure and other cardiovascular risk factors in borderline to mild hypertension. PATIENTS AND METHODS: We studied 779 patients with borderline to mild hypertension (mean +/- SEM age 33 +/- 0.3 years; mean +/- SEM office blood pressure 146 +/- 0.4/94 +/- 0.2 mmHg) at 17 hypertension clinics in northeast Italy. Office and 24-h blood pressures were recorded with simultaneous urine collection for albumin measurement. In 510 subjects, left ventricular mass was measured by echocardiography. RESULTS: Subjects with overt (> or = 30 mg/24 h) and borderline (16-29 mg/24 h) microalbuminuria had similar 24-h blood pressure levels, higher than those in the subjects without microalbuminuria. In the univariate and multiple regression analyses the albumin excretion rate was closely correlated with 24-h systolic blood pressure and not related to age, body mass index, metabolic parameters, lifestyle factor and degree of left ventricular hypertrophy. CONCLUSIONS: Borderline values of urinary albumin excretion (16-29 mg/24 h) may be clinically relevant in subjects with borderline to mild hypertension. Renal and cardiac damage do not develop in parallel in the initial phases of hypertension.


Asunto(s)
Albuminuria/orina , Hipertensión/fisiopatología , Hipertrofia Ventricular Izquierda/diagnóstico por imagen , Adulto , Albuminuria/fisiopatología , Monitoreo Ambulatorio de la Presión Arterial , Ecocardiografía , Femenino , Humanos , Hipertensión/diagnóstico por imagen , Hipertensión/metabolismo , Hipertrofia Ventricular Izquierda/fisiopatología , Masculino , Análisis de Regresión , Estudios Retrospectivos , Factores de Riesgo
18.
J Hypertens ; 14(1): 47-52, 1996 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-12013494

RESUMEN

OBJECTIVES: To define whether a diurnal rhythm of peripheral resistance exists in normotensive and hypertensive subjects, has any relationship with that of blood pressure and differs in dipper and non-dipper hypertensives. DESIGN AND METHODS: Forty-three subjects (13 normotensives and 30 mild-to-moderate essential hypertensives) confined for 24 h to bed were included. Blood pressure was recorded for 22 h at 15 min intervals, plethysmographic forearm flow was simultaneously measured and forearm resistance calculated. The analysis was performed for the whole 22 h period and for three 4 h truncated periods, two of certain wakefulness and one of certain sleep. RESULTS: A circadian rhythm of forearm resistance was shown in the normotensives, paralleling that of blood pressure. All the normotensives were dippers, with a nocturnal blood pressure dip (systolic/diastolic) of -4.5/-6.0%. In the hypertensives, the day/night blood pressure trends were not homogeneous: 21 showed higher blood pressure values during waking time, with a trend quite similar to that of the normotensives, whereas the other nine were non-dippers. Resistance was lower during sleep than during waking both in the normotensives and in the dipper hypertensives, whereas in the non-dippers it was higher during sleep. CONCLUSIONS: A sleep/waking rhythm of peripheral resistance with the highest values during daytime and the lowest during night-time does exist in normotensive as well as in the majority of hypertensive subjects resting continuously in bed, and therefore is largely independent of physical activity. Only in a minority of hypertensive patients are higher values of peripheral resistance present during sleep.


Asunto(s)
Lechos , Presión Sanguínea/fisiología , Ritmo Circadiano/fisiología , Antebrazo/irrigación sanguínea , Hipertensión/fisiopatología , Resistencia Vascular/fisiología , Adulto , Factores de Edad , Índice de Masa Corporal , Femenino , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Persona de Mediana Edad , Valores de Referencia , Factores Sexuales
19.
J Endocrinol ; 160(2): 275-83, 1999 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9924197

RESUMEN

We examined the presence and the regulation of nitric oxide (NO) synthase (NOS) using in vitro cultured corpora lutea (CL) obtained from rabbits at days 4 and 9 of pseudopregnancy. The role of NO and NOS on steroidogenesis was also investigated using the same CL preparations after short-term incubations (30 min and 2 h) with the NO donor, sodium nitroprusside (NP), the NOS inhibitor, Nomega-nitro-l-arginine methyl ester (l-NAME) and prostaglandin (PG) F-2alpha. The basal NOS activity was greater in CL at day 4 than at day 9, and was also differently modulated by PGF-2alpha, depending on the age of the CL. The addition of PGF-2alpha to day 4 CL had no effect, but PGF-2alpha on day 9 caused a threefold increase in NOS activity. NP caused a two- to fivefold decrease in release of progesterone from CL of both ages, and this inhibitory effect on steroidogenesis was reversed by l-NAME. All treatments failed to modify basal androgens and 17beta-oestradiol was not detectable in either control or treated CL. These results suggest that NO is effectively involved in the regulation process of steroidogenesis, independently of 17beta-oestradiol. PGF-2alpha had no effect on day 4, but induced luteolysis on day 9, by reducing progesterone (P

Asunto(s)
Cuerpo Lúteo/metabolismo , Óxido Nítrico Sintasa/metabolismo , Progesterona/biosíntesis , Análisis de Varianza , Animales , Cuerpo Lúteo/efectos de los fármacos , Técnicas de Cultivo , Dinoprost/farmacología , Activación Enzimática , Inhibidores Enzimáticos/farmacología , Femenino , NG-Nitroarginina Metil Éster/farmacología , Donantes de Óxido Nítrico/farmacología , Óxido Nítrico Sintasa/antagonistas & inhibidores , Nitroprusiato/farmacología , Seudoembarazo , Conejos , Factores de Tiempo
20.
Menopause ; 7(3): 193-9, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-10810965

RESUMEN

OBJECTIVE: Early studies of menopause recruited sample populations from clinical settings; however, in the 1970s, populations drawn from health care settings were characterized as nonrepresentative because of symptom overreporting. This pilot study was carried out to test whether this characterization still holds true: that women who are drawn from clinical settings report more symptoms compared with women who are recruited from community and work sites. DESIGN: Open-ended interviews were carried out with patients aged 40-60 years in a physician's office (n = 50), in a chiropractor's office (n = 24), at two Breast Health Project sites (n = 50), and in several non-health care sites in the community (n = 81). Interviews were supplemented by anthropometrics and standardized return-by-mail questionnaires. RESULTS: Women who experienced hot flashes and sweating were more likely to report having spoken with a physician about menopause. However, women who were drawn from the clinical setting were not significantly more likely to describe hot flashes, sweats, or mood changes and were significantly less likely to report headaches in relation to menopause compared with a community sample. Women who were drawn from the physician's office were more likely to use hormone replacement therapy and to have had a hysterectomy. CONCLUSIONS: This study suggests that because of the medicalization of menopause, we need to rethink our assumptions about the characteristics of populations drawn from health care settings. In western Massachusetts, place of recruitment did not predict symptom frequency.


Asunto(s)
Menopausia , Selección de Paciente , Adulto , Afecto , Mama , Consejo , Atención a la Salud , Terapia de Reemplazo de Estrógeno , Femenino , Ginecología , Cefalea , Sofocos , Humanos , Histerectomía , Persona de Mediana Edad , Obstetricia , Rol del Médico , Encuestas y Cuestionarios , Salud de la Mujer
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