Differences in arterial stiffness and target organ damage between native Greek patients and immigrants from Eastern European countries with essential hypertension.

AIM: The variance in hypertension-related sequelae between different ethnic groups is highly related to differences in socioeconomic conditions and lifestyle habits, but also to disparities in the awareness and treatment of the disease. In the present study, we sought to evaluate the target organ damage in a vulnerable hypertensive population, such as the Eastern European immigrants. METHODS: The study population consisted of 128 hypertensive patients: 67 immigrants from Eastern Europe and 61 native inhabitants. Anthropometric, biochemical and echocardiographic data were derived from both groups. Both groups underwent fundoscopic examination and pulse wave velocity (PWV) measurements for assessment of arterial stiffness. RESULTS: Although immigrants had lower body mass index compared to native inhabitants (P<0.001), they had significantly increased arterial stiffness (P=0.003). In multivariate analysis, higher carotid-femoral PWV was significantly associated with immigration status [ß (SE)=0.935(0.443), P=0.041], after adjustment for smoking status. Moreover, immigrants had increased left atrial volume index (LAVI) (P<0.001), left ventricular mass index (P<0.001) and higher rates of left ventricular diastolic dysfunction (p=0.047). In multivariate analysis, LAVI was significantly associated with immigration status (ß (SE)=5.17(1.93), P=0.01) after adjustment for serum glucose levels and age. Finally, immigrants had significantly higher levels of sodium urinary excretion (p=0.007) and lower glomerular filtration rate (P<0.001). CONCLUSION: Our findings suggest that hypertensive immigrants exhibit an aggravated arterial stiffness profile and increased risk of target organ damage. These findings could be attributed to differences in socioeconomic conditions and dietary habits.

Analysis of the expression of putatively imprinted genes in bovine peri-implantation embryos.

The application of assisted reproductive technologies (ART) has been shown to induce changes in the methylation of the embryonic genome, leading to aberrant gene expression, including that of imprinted genes. Aberrant methylation and gene expression has been linked to the large offspring syndrome (LOS) in bovine embryos resulting in increased embryonic morbidity and mortality. In the bovine, limited numbers of imprinted genes have been studied and studies have primarily been restricted to pre-implantation stages. This study reports original data on the expression pattern of 8 putatively imprinted genes (Ata3, Dlk1, Gnas, Grb10, Magel2, Mest-1, Ndn and Sgce) in bovine peri-implantation embryos. Two embryonic developmental stages were examined, Day 14 and Day 21. The gene expression pattern of single embryos was recorded for in vivo, in vitro produced (IVP) and parthenogenetic embryos. The IVP embryos allow us to estimate the effect of in vitro procedures and the analysis of parthenogenetic embryos provides provisional information on maternal genomic imprinting. Among the 8 genes investigated, only Mest-1 showed differential expression in Day 21 parthenogenetic embryos compared to in vivo and IVP counterparts, indicating maternal imprinting of this gene. In addition, our expression analysis of single embryos revealed a more heterogeneous gene expression in IVP than in in vivo developed embryos, adding further to the hypothesis of transcriptional dysregulation induced by in vitro procedures, either by in vitro maturation, fertilization or culture. In conclusion, effects of genomic imprinting and of in vitro procedures for embryo production may influence the success of bovine embryo implantation.

Effect of chronic coffee consumption on aortic stiffness and wave reflections in hypertensive patients.

OBJECTIVE: Aortic stiffness and wave reflections are important markers and prognosticators of cardiovascular risk. Caffeine increases acutely aortic stiffness and wave reflections. Furthermore, chronic coffee consumption is associated with increased aortic stiffness and wave reflections in normotensive subjects. In the present study, we aimed to assess the association between chronic coffee consumption, and aortic stiffness and wave reflections in hypertensive patients. DESIGN: Epidemiological survey. SETTING: Hypertension Unit, University Hospital. SUBJECTS-METHODS: We examined 259 never-treated hypertensives (age 50+/-12 years, 165 males) without diabetes mellitus, who were asked to describe in detail the type and amount of coffee they consumed. Carotid-femoral pulse wave velocity (PWV) and augmentation index (AIx) were measured non-invasively as indices of aortic stiffness and wave reflections, respectively. RESULTS: When controlled for gender, age, height, smoking status, heart rate, mean pressure, HDL cholesterol and hsCRP, AIx was found to be higher with increasing daily coffee consumption. Post hoc analysis revealed that all groups of coffee consumption had higher AIx compared to no-consumption. PWV did not differ among groups of daily coffee consumption. Each participant had 35% higher relative risk of having high AIx for each cup (150 ml) of coffee per day, and 40% higher relative risk for each 10 cup-years. CONCLUSIONS: Coffee consumption is associated with increased wave reflections, but not aortic stiffness in never-treated hypertensive patients. This finding may have important clinical implications for cardiovascular health in hypertensive subjects.

Morphological assessment of preimplantation embryo quality in cattle.

The extensive use of embryo technologies has emphasized the need for assessing embryo quality by morphological techniques, such as transmission electron microscopy, immunocytochemistry for confocal laser scanning microscopy and fluorescence in situ hybridization. By a combination of these techniques, it has been possible to demonstrate: (i) that rRNA gene activation, as monitored by embryonic nucleolar development, is comparable in bovine embryos developed in vivo and produced in vitro, whereas reconstructed nuclear transfer embryos may be deviant, (ii) that generating embryos by both in vitro production and reconstruction by nuclear transfer is associated with increased occurrence of apoptosis, in particular in the inner cell mass of blastocysts, and (iii) that these two embryo production techniques are associated with increased occurrence of mixoploidy that is, embryos presenting a large population of normal diploid cells and a small population of abnormal haploid or polyploid cells. It is clear that blastocysts that appear healthy at stereomicroscopy may have subcellular defects. Therefore, the possibility of long-term evaluation in vitro of embryos after hatching has been examined. However, whereas embryos developing in vivo after hatching present a number of well defined developmental milestones, such as elongation of the trophoblast, formation of hypoblast and epiblast followed by differentiation of endoderm, mesoderm and ectoderm, in vitro culture systems for development beyond the blastocyst stage currently allow the embryo to complete only a single milestone, namely hypoblast formation.

Immunohistochemical and ultrastructural characterization of the initial post-hatching development of bovine embryos.

The problems of sustaining placenta formation in embryos produced by nuclear transfer have emphasized the need for basic knowledge about epiblast formation and gastrulation in bovine embryos. The aims of this study were to define stages of bovine post-hatching embryonic development and to analyse functional mechanisms of germ-layer formation. Embryos developed in vivo were collected after slaughter from superovulated cows on days 9, 11, 14 and 21 after insemination and processed for transmission electron microscopy (n = 26) or immunohistochemistry (n = 27) for potential germ-layer characterization (cytokeratin 8 for potential ectoderm; alpha-1-fetoprotein for potential endoderm; and vimentin for potential mesoderm). On day 9, the embryos were devoid of zona pellucida and presented a well-defined inner cell mass (ICM), which was covered by a thin layer of trophoblast cells (the Rauber's layer). Formation of the hypoblast from the inside of the ICM was ongoing. On day 11, the Rauber's layer was focally interrupted and adjacent underlying ICM cells formed tight junctions. The hypoblast, which formed a thin confluent cell layer, was separated from the ICM and the tropho-blast by intercellular matrix. The embryos were ovoid to tubular and displayed a confluent hypoblast on day 14. The epiblast was inserted into the trophoblast epithelium and tight junctions and desmosomes were present between adjacent epiblast cells as well as between peripheral epiblast and trophoblast cells. In some embryos, the epiblast was more or less covered by foldings of trophoblast in the process of forming the amniotic cavity. Cytokeratin 8 was localized to the trophoblast and the hypoblast underlying the epiblast; alpha-1-fetoprotein was localized to most hypoblast cells underlying the trophoblast; and vimentin was localized to most epiblast cells. On day 21, the smallest embryos displayed a primitive streak and formation of the neural groove, whereas the largest embryos presented a neural tube, up to 14 somites and allantois development. These embryos depicted the gradual formation of the endoderm, mesoderm and ectoderm as well as differentiation of paraxial, intermediate and lateral plate mesoderm. Cytokeratin 8 was localized to the trophoblast, the hypoblast and the surface and neural ectoderm; and alpha-1-fetoprotein was localized to the hypoblast, but not the definitive endoderm, the intensity increasing with development. Vimentin was initially localized to some, but not all, cells positioned particularly in the ventral region of the primitive streak, to presumptive definitive endoderm cells inserted into the hypoblast, and to mesoderm. In conclusion, within 2 weeks of hatching, bovine embryos complete formation of the hypoblast and the epiblast, establishment of the amniotic cavity, ingression of epiblast cells for primitive streak formation, involution of cells through the node and the streak for endoderm and mesoderm fomation, neurulation and differentiation of the mesoderm. The recruitment of cells from the epiblast to form the primitive streak as well as the endoderm and mesoderm is associated with expression of the intermediate filament vimentin.

Genetic follow-up of male offspring born by ICSI, using a multiplex fluorescent PCR-based test for Yq deletions.

De-novo deletions involving AZFa, b, c and d are one of the most common chromosomal aberrations in man resulting in defective spermatogenesis and male infertility. Currently, Yq deletion screening involves either single or multiplex PCR using Y-specific sequence tagged site markers and the subsequent analysis of the amplification products on ethidium bromide-stained agarose gels. To improve the practicality of routine and high throughput Yq testing, we have developed a more sensitive multiplex fluorescent (FL)-PCR screening system using genomic DNA extracted from cheek buccal cells as a readily available PCR template. For genetic follow-up studies of ICSI-conceived children, we also developed a DNA fingerprinting system based on the co-amplification of four highly polymorphic markers to validate family samples and detect any potential extraneous DNA contamination that could cause a misdiagnosis. Multiplex FL-PCR analysis of buccal cell DNA from two infertile men who conceived three sons by ICSI demonstrated that their Yq deletions were vertically transmitted. Fine mapping with additional Yq markers revealed identical deletion endpoints involving the loss of AZFdc sequences. This firstly indicates that the extent of the Yq deletion was unchanged on ICSI transmission and secondly supports the view that AZFdc deletions may arise by a common de-novo event. Analysis of paternal, maternal and sibling DNA fingerprints showed the co-inheritance of parental alleles by each male child and confirmed the expected relationship between each family member. The application of these new FL-PCR based screening tests in genetic follow-up studies will assist in confirming transmission of specific genetic defects to male offspring conceived by ICSI and provide a basis for genetic counselling and potential treatment options as these boys approach sexual maturity.

Immunization coverage among predominantly Hispanic children, aged 2-3 years, in central Los Angeles.

PURPOSE: To assess the immunization status of young children in a predominantly Hispanic region in and around downtown Los Angeles, and factors associated with complete immunization by age 24 months. METHODS: The information was gathered in a two-stage cluster survey with probability proportionate to estimated size (PPS) sampling of 30 clusters at the first stage, and simple random sampling of a constant number of children at the second stage. Vaccination coverage was determined by a review of the home immunization (HI) card, or of clinic records. RESULTS: Of the 270 sampled children, 91.5% were Hispanic and 6.7% were Black. Home telephone numbers were not available in 24.8% of the homes, and 34.1% reported having no health insurance. Vaccination coverage was over 90% for the first three doses of Diphtheria, tetanus toxoids and pertussis/ diphtheria, tetanus toxoids and acellular pertussis vaccine (DTP/DTaP)/Diphtheria and tetanus toxoids vaccine (DT), first two doses of poliovirus (Polio) vaccine, first dose of measles, mumps and rubella (MMR) vaccine, and first two doses of hepatitis B (Hep B) vaccine. Yet, by age 24 months, only 72.2% of the children had received the combined series of 4:3:1 (i.e., four DTP/DTaP/DT, three Polio, one MMR). This was further reduced to 64.4% for the combined series of 4:3:1:3:3 (i.e., four DTP/DTaP/ DT, three Polio, one MMR, three Haemophilus influenzae type b (Hib), three Hep B). Factors associated with completed on-time vaccination were having an HI card available during the interview and being enrolled in Supplemental Nutrition Program for Women, Infants and Children (WIC). CONCLUSIONS: While vaccination levels for individual antigens were found to be high, more emphasis needs to be placed on getting preschool children vaccinated on-time according to the Recommended Childhood Immunization Schedule.

MEG and ECoG localization accuracy test.

We tested the localization accuracy of magnetoencephalography (MEG) and electrocorticography (ECoG) for a current dipole in a saline filled sphere at depths ranging from 1 to 6 cm at 1 cm intervals. We used standard neuromagnetometer placements and subdural electrode grids, previously employed for patient studies, with precise measurements of sensor and electrode locations with a 3-dimensional spatial digitizer. MEG and ECoG had comparable accuracy with mean errors of 1.5 and 1.8 mm, respectively. It appears that use of the spatial digitizer increases accuracy for both MEG and EGoG localizations. The larger errors in the ECoG with increasing depths could be attributed to under-sampling of the spatial pattern of the field which spreads out with deeper sources. It should be noted that in clinical applications a grid of the dimensions used here would most typically be used for superficial sources on the cortex with depth recordings being preferred for investigations of deep epileptogenic activity. Results are encouraging for continued development of non-invasive MEG methods for further definition of epileptogenic zones in the brain.

Phase-matched electromagnetic scattering in active dielectric films.

An investigation of oblique plane-wave electromagnetic scattering from active dielectric films reveals the existence of anomalously large resonances that occur at discrete plane-wave angles of incidence. These resonances may be understood from a leaky-wave phase-matching condition whose predictions for the first few modes agree to within a few percent of those obtained from a rigorous treatment using Maxwell's equations. Enhancement in the scattered-field intensities of the order of 100 was observed in experiments using finite-diameter pump and probe laser beams and active films as thin as 6 microm.

Light amplification by evanescent wave coupling in a multimode fiber.

Amplification of light propagating as bound modes of a multimode fiber through evanescent wave coupling is reported. Experiments have been performed by immersing sections of a stripped fiber 2-20 cm long in a Kiton red dye solution which is pumped by the evanescent fields of a cw Ar-ion laser also propagating as bound modes of the fiber. Gain coefficients as high as 0.02/cm have been observed by a 633-nm He-Ne probe beam when pumped by a 5-W laser. Numerical calculations obtained by performing a Taylor series expansion of the eigenvalue equation for a cylindrical waveguide with a small active component in the cladding region show that modes near cutoff can exhibit gains 60% or higher, approaching those assumed for the cladding region.

Improvement of the coupling efficiency between LEDs and optical fibers.

A truncated spherical lens geometry is evaluated for layered lenses with various index profiles to determine power coupling efficiency between an LED and an optical fiber. The equations for the efficiency calculation through multiple boundaries are discussed, and numerical results are presented for optical fibers with numerical aperture values of 0.14, 0.23, and 0.35. The layered Luneburg profile is found to give the highest efficiency when the lens and fiber have a significantly larger size than the LED. The layered Maxwell fisheye profile is most efficient when the lens, fiber, and LED are of similar radius.

Electromagnetic scattering from active objects: invisible scatterers.

The scattering properties of active particles are studied and compared with those of particles with a complex conjugate (passive) index of refraction. It is shown that the extinction cross section of active particles is zero at certain frequencies and that only at certain frequency bands it is amplified. For most frequencies, the interference between diffracted and refracted waves causes the extinction cross section to behave like that of passive particles. A comparison of backscattered and forwardscattered intensities between active and passive particles with n(a) = n(p) * shows that as +/- Im(n) ? + infinity the intensities converge to the same value. For nonsymmetric scatterers, such as cylindrical fibers of elliptic cross section, it is shown that in the resonance region the major portion of the scattered field is not in the forward direction. In addition, the ratio of backscattered to forward scattered intensity is found to be greater than unity for active media for certain frequencies beyond the low frequency region.

Geometrical optics of inhomogeneous particles: glory ray and the rainbow revisited.

The glory ray and the rainbow are analyzed by considering the scattering of light from inhomogeneous particles. It is shown that melting ice crystals may be strong contributors to the glory ray. Geometrical optics is used to investigate and catalog a wide variety of particle inhomogeneities which support rainbow and glory rays.