Possibility of a common origin to ferroelectricity and superconductivity in oxides.
Explore the source record for details and available documents.
Journal Article↗
Biomedical subjects
A Simon
Publications and source records attributed to A Simon.
Double transfer of embryos in in vitro fertilization, or is there a delayed receptivity of the endometrium?
Sixty-seven in vitro fertilization (IVF) patients who underwent ultrasonically guided oocyte pickup (OPU) after induction of superovulation with human menopausal gonadotropins were submitted to two different protocols of embryo transfer. In the first group of 33 patients, four to five embryos were transferred to the uterus 48 hr after OPU. In the second group of 34 patients two to three embryos were transferred at 48 hr after OPU and two other embryos were transferred after freezing and thawing 48 hr later (96 hr after OPU). The pregnancy rate achieved in the double embryo transfer (ET) protocol was significantly higher than in the single-ET protocol (32.4 vs. 18.2%, respectively; P less than 0.05).
Embryo Transfer↗
Preload, adrenergic activity, and aortic compliance in normal and hypertensive patients.
Aortic compliance is a major determinant of systolic blood pressure and of impedance to left ventricular ejection. However, little is known about its regulating factors. To assess the effects of preload and adrenergic activity on aortic compliance, we studied 10 normal subjects and nine untreated hypertensive patients at rest and during lower body negative pressure. Aortic compliance was measured invasively from the diastolic decay of the aortic pressure tracing and systemic vascular resistance. Preload was decreased stepwise by lower body negative pressure (-5 to -40 mm Hg) while adrenergic activity was assessed by the change in plasma norepinephrine at a maximum level of negative pressure suction. At rest, aortic compliance was lower in hypertensive subjects compared with its value in normal individuals (0.048 +/- 0.012 [SD] versus 0.071 +/- 0.009 units, p less than 0.001) but correlated inversely with systolic blood pressure in both groups (r = -0.64 in normotensive individuals, r = -0.83 in hypertensive subjects, r = -0.88 for the whole group, p less than 0.001 for all). Whereas resting pulmonary wedge pressure was higher in hypertensive subjects compared with normal individuals (16 +/- 4 [SD] versus 11 +/- 3 mm Hg, p less than 0.05), resting plasma norepinephrine levels were not different between the two groups (261 +/- 139 versus 251 +/- 103 pg/ml). Neither of these two resting indices correlated with baseline aortic compliance in both normotensive individuals and hypertensive patients. During lower body negative pressure (LBNP), cardiac filling pressure (right atrial pressure and pulmonary wedge pressure) as well as cardiac output decreased in the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Aorta↗
Double antigen localization of two catecholamine enzymes and GABA in amacrine cells of the rat retina in semi-thin sections.
A double immunohistochemical labeling technique was developed with two immunoperoxidase reactions performed before and after embedding in epoxy resin using two different chromogens: diaminobenzidine (yellowish brown color) and diaminobenzidine + nickel ammonium sulfate (black color). The two catecholamine enzyme immunoreactivities (phenylethanolamine-N-methyltransferase, and tyrosine-hydroxylase) were not found in the same cells, while gamma-aminobutyric acid (GABA) immunoreactivity was observed in large tyrosine-hydroxylase immunoreactive cells, but not in phenylethanolamine-N-methyltransferase immunoreactive cells.
3,3'-Diaminobenzidine↗
Comparative long-term vasoactive effects of atenolol and carteolol on the properties of the small and large arteries of the upper extremities in human essential hypertension.
The long-term effects of selective (atenolol) and nonselective (carteolol) beta-blockers on brachial artery diameter velocity and flow and on vascular resistance (pulsed Doppler) were compared in two groups of 10 hypertensive patients at respective daily doses of 100 and 20 mg. The drugs decreased mean blood pressure (p less than 0.01) with similar magnitude, although systolic blood pressure was decreased more by atenolol than by carteolol (p less than 0.05). Heart rate was decreased by atenolol (p less than 0.01) but was unchanged by carteolol. The drugs did not change brachial circulation when the hand circulation was present. During hand exclusion (wrist occlusion) comparison from baseline showed that atenolol decreased velocity and flow (p less than 0.01, p less than 0.05) and increased resistance (p less than 0.05), whereas carteolol decreased resistance (p less than 0.05); after 3 months of treatment, velocity and flow were higher (p less than 0.01, p less than 0.001) and resistance was lower (p less than 0.01) with carteolol than with atenolol. Thus, hand exclusion demonstrated opposite drug effects on arterioles--dilation for carteolol and constriction for atenolol.
Adult↗
Platelet cytosolic proton and free calcium concentrations in essential hypertension.
Alterations in the metabolism of intracellular messengers, such as calcium and cyclic adenosine 5'-phosphate (cAMP), have been reported in essential hypertension. Since intracellular pH (pHi) participates in the control of fundamental cell functions, we looked for changes in platelet cytosolic H+ concentration [( H+]i) in hypertension and investigated whether or not its impaired metabolism is linked to the calcium handling abnormalities. The fluorescent pH indicator BCECF has been used to evaluate intracellular H+ concentration in platelets, unstimulated ex vivo, from normotensive (n = 20) and hypertensive patients (n = 20). Cytosolic [H+] was 20% lower in hypertensive than in normotensive subjects (49.5 +/- 3.4 and 61.8 +/- 2.2 nmol/l cells, respectively, P less than 0.005; mean pHi values were 7.21 and 7.33, respectively). Platelet cytosolic H+ and free Ca2+ concentrations ([Ca2+]i) were determined in parallel in 15 normotensive and 15 hypertensive patients. [Ca2+]i was found to be 19% higher (P less than 0.01), and [H+]i 22% lower (P less than 0.02), in the hypertensive patients compared with the normotensive subjects. Platelet pHi and [Ca2+]i were increased simultaneously in some hypertensive patients. These results are compatible with the hypothesis of an in vivo activation of platelets in hypertension. If a similar alkalinization exists in smooth muscle cells, it may participate in cell proliferation and in an enhanced sensitivity to agonists, two parameters thought to be involved in blood pressure elevation.
Adult↗
Pseudorabies virus displays variable numbers of a repeat unit adjacent to the 3' end of the glycoprotein gII gene.
The coding region of the glycoprotein complex gII of pseudorabies virus (PRV) is located in the unique long part of the genome on SalI subfragments 1A and 1G of BamHI fragment 1 (map units 0.105 to 0.130). Fragment 1G which includes the 3' end of the gII gene displays a size heterogeneity among different PRV strains and also within plaque isolates of a given strain. To reveal the cause of this heterogeneity and whether it might affect the gII-coding region we sequenced different 1G fragments of the PRV strains Ka, Phylaxia and Dessau, and determined the 3' end of the gII mRNA by S1 analysis. These data show that the size heterogeneity is caused by the presence of a variable number of tandemly repeated DNA sequence downstream but adjacent to the coding region of the glycoprotein gII gene. The 3' end of the gII mRNA was mapped about 24 bp upstream of the first repeat unit. A 15 bp sequence 5' GGGACGGAGGGGAGA 3' is repeated from three to over 50 times in different 1G fragments. It is the only repeat unit present in strain Ka, whereas the Phylaxia and Dessau strains show additional modifications.
Base Sequence↗
Postnatal development of tyrosine-hydroxylase-immunoreactive cells in the rat retina. Morphology and distribution.
The appearance and development of tyrosine-hydroxylase-immunoreactive cells were studied using whole mounts of postnatal rat retinas. The two classes of cells described in the adult retina were observed in the young rat. Small unipolar cells appeared as soon as the day of birth in the superior retina and large stellate cells by postnatal day (PND) 7. By PND 10, their number reached that of stellate cells of the adult-retina. It is hypothesized that small unipolar cells are transformed into large stellate cells as they mature. Several arguments are put forward to support this conclusion, the most important of which is the appearance of peripheral crescents containing a high density of small cells which disappear proportionately as the number of large stellate cells increases. The development of the vasculature was also studied. By PND 7, it was more developed in the temporal superior quadrant, in the region where the first stellate cells appeared.
Animals↗
Manipulating the follicular phase in IVF cycles: a comparison of two hMG stimulation protocols.
The results of two human menopausal gonadotropin (hMG) protocols of ovulation induction for in vitro fertilization (IVF) were compared. With the first protocol, 28 women (group 1) were treated with an hMG dosage which was increased stepwise. With the second, 30 women (group 2) were treated with a high dose of hMG for 2 days, then given a constant daily dose. The two groups were compared with regard to ovarian response, luteal phase and laboratory and clinical outcomes of IVF. They were comparable as regards the total number of hMG doses required, the number of large follicles (mean diameter greater than 15 mm) on day 0 (day of human chorionic gonadotropin (hCG) administration), serum estrogen (E2) and progesterone (P) levels throughout the cycle and IVF laboratory and clinical outcomes. They differed significantly (p less than 0.01) only in the number of secondary smaller follicles (mean diameter less than 15 mm) observed on day 0 (3.7 +/- 0.4 for group 1 and 5.3 +/- 0.4 for group 2). Manipulating the hMG dosage during the early-mid follicular phase does not affect follicular synchrony, the number of oocytes harvested and the number of embryos achieved.
Adult↗
[Non invasive evaluation of endothelial shearing phenomena in human arteries. Application to essential hypertension].
Pulsatile wall shear conditions close to the brachial artery were evaluated in 11 normotensive and in 19 hypertensive patients of similar age by determining arterial diameter and centerline blood velocity with a pulsed Doppler and blood viscosity at 96 sec-1 with a coaxial cylinder viscometer. A Womersley model of intraluminal distribution of blood velocities enabled to determine from unsteadiness parameter alpha of Womersley, arterial diameter and maximal minimal and pulse (maximal-minimal) values of centerline velocity, the maximal minimal and pulse shear rate and shear stress (product between shear rate and viscosity) close to the endothelium. Compared to normotensives hypertenvises had higher arterial diameter (p less than 0.001), lower maximal minimal and pulse centerline velocities (p less than 0.001, p less than 0.01, p less than 0.001) higher blood viscosity (p less than 0.001), lower maximal, minimal and pulse wall shear rate (p less than 0.001, p less than 0.05, p less than 0.001) and lower maximal minimal and pulse shear stress (p less than 0.01). In the overall normotensive and hypertensive group, mean blood pressure negatively correlated to maximal minimal and pulse shear rates (r = -0.65; r = -0.45, r = -0.63) and to maximal, minimal and pulse shear stress (r = -0.46; r = -0.37, r = -0.48). Thus, hypertension is associated with a reduction of oscillating shear conditions in the viscosity of the brachial artery wall which might in long term influence structural and/or functional response to the endothelium.
Adult↗
[Essential hypertension and platelet cytosolic concentrations of H(+) and Ca2(+)].
Essential hypertension is associated with various cell abnormalities, including alterations in the metabolism of intracellular messengers, such as cytosolic free Ca2+ and cyclic AMP or IP3. Intracellular pH is implicated in the regulation of number vital functions, including cell metabolism, division and response to various stimuli. We have measured cytosolic H+ concentration ([H+]i) in human platelets and investigated a possible relationship with free Ca2+ concentrations ([Ca2+]i) in hypertensive patients. [H+]i was determined with the pH sensitive fluorescent probe BCECF in platelets from 15 normotensive subjects and 15 patients with mild to moderate essential hypertension, free from medication, il any, for at least two weeks. Donor characteristics are indicated in the table. (table; see text) [H+] cytosolic from hypertensive patients was significantly lowered by 21 p. 100 compared to normotensive values (table). Cytosolic free Ca2+ concentrations, measured with the Ca2+ fluorescent probe Fura2, were significantly increased by 19 p. 100 in platelets from hypertensive patients when compared to those of normotensive donors. Taken all together, [H+]i and [Ca2+]i varied inversely (r = -0.421, p = 0.02) in these thirty donors and tends to be correlated in the essential hypertensive patients (r = 0.490, p = 0.06). This correlation remained significant at constant age systolic and diastolic blood pressures. The simultaneous rise in [H+]i and [Ca2+]i in platelets from essential hypertensive patients are compatible with their observed enhanced sensitivity to several aggregating agents. This alkalinisation, if present in the vascular smooth muscle cells, may also reflect facilitated cell proliferation and increased sensitivity to stimulating agents, two parameters implicated in the rise of arterial blood pressure.
Adult↗
[Blood viscosity is a chronic adjustment factor of arterial vasodilatation in humans].
Arteriolar geometry and blood viscosity, the two main factors determining vascular resistance were studied in 44 normotensive subjects and 106 hypertensive patients at the brachial circulation level. Vascular resistance was calculated as the ratio between mean blood pressure and mean arterial flow determined by pulsed Doppler. Blood viscosity at 240 sec-1 was measured with a coaxial cylinder viscometer: Compared to controls, hypertensive patients had higher vascular resistance (161 + 8 vs 124 + 9 mmHg.ml-1.sec, P less than 0.05) and higher viscosity (4.75 + 0.05 vs 4.50 + 0.07 mPasec, P less than 0.01). Vascular resistance was negatively correlated to blood viscosity both in control (r = 0.48; P less than 0.001) and in hypertensive (r - 0.39, P less than 0.001) groups. Arteriolar equivalent radius (a) calculated from Poiseuille's equation from the relation a = (8 mu/pi R) 1/4 was positively correlated to viscosity in the two regressions were statistically different (P less than 0.001) indicating that at higher viscosity levels, arteriolar equivalent radius had lesser increase in normotensive than in hypertensive groups. Thus chronic increase in blood viscosity is accompanied by a small vessels vasodilatory phenomenon which seems less efficient in normotensive than in hypertensive subjects and might contribute in part to the mechanisms of vascular resistance elevation observed in hypertension.
Adult↗
[Paradoxal diminution of resistance of the large arteries in human essential hypertension].
Segmental pressure drop and longitudinal resistance of brachial artery were evaluated in 11 normotensive (NT) and 19 hypertensive (HT) subjects of similar age by measuring arterial diameter (D), blood velocity (V) and flow (Q) with pulsed Doppler and blood viscosity (mu) at 96 sec-1 with a coaxial cylinder viscometer. Mean pressure drop (delta P) per unit of length of artery was calculated according to the relation delta P = 4 tau/D, where tau is the mean wall shear stress evaluated on the basis of a Poiseuille velocity profile by the formula: r = vV/D. Brachial artery resistance per unit of length was deduced as the (delta P/Q) ratio. (table; see text) In the overall normotensive and hypertensive group, (n = 30), pressure drop (delta P) was negatively correlated with mean blood pressure (r = -0.55, P less than 0.01). Despite increased viscosity hypertensive patients have a decreased resistance of large arteries whose mechanisms include a reduction in shear stress close to the endothelium and a dilation of the conduit artery; these two abnormalities contribute to decrease the viscous force of the circulating blood column against the arterial wall.
Adult↗
[Visco-elastic characteristics of the aorta in conscious dogs in a model of experimental calcinosis].
Effects of experimental calcinosis induced by daily overdose of 500.000 IU Vit D3 during 10 days were studied in 6 mongrel conscious dogs chronically instrumented with intra-aortic Konigsberg microtransducer and two ultrasonic piezo-electric crystals diametrically opposed in the adventitia of the descending thoracic aorta. Simultaneous recording of instantaneous aortic pressure and diameter waves in basal state and during transient acute hypertension induced by intravenous angiotensin bolus (0.1 microgram/kg) allowed to obtain the pressure (y) diameter (x) relationship of the aorta according to an exponential regression: P = expo (beta D + A), with a highly significant correlation coefficient in all animals (r greater than 0.99). (table; see text) Anatomopathological studies of aortas revealed abnormal calcium deposition, ruptures of elastic fibers and disorganization of collagen. Thus, a striking decrease in aortic rigidity is observed after calcinosis in relation with structural changes of elastic materials and responsible in part for a reduction in pulsatile pressure; moreover this unexpected phenomena might represent an initiative process of development of aortic aneurysms.
Animals↗
In vitro fertilization. Correlation of vaginal cytology and hormonal profile with success rates.
Cytologic parameters of the vaginal epithelium in 59 women undergoing in vitro fertilization-embryo transfer (ET) were correlated with plasma levels of 17-beta estradiol and progesterone on the oocyte pickup (OPU) and ET days. On the OPU day a late proliferative/late proliferative-early secretory pattern was observed in 84.6% of the 13 women who conceived (group 1) but in only 52% of the 46 who failed to conceive (group 2) (P less than .04). On the ET day a secretory phase appeared in 100% and 61% of group 1 and 2 patients, respectively (P less than .01). Between the OPU and ET days the mean karyopyknotic index dropped by 60% and 13% in group 1 and 2 patients, respectively (P less than .001). It seems that a high estrogenic effect followed by an advanced progestational environment, on the OPU and ET days, respectively, can provide a favorable milieu for implantation.
Embryo Transfer↗
The 1984 national perinatal census: design, organization and uses for assessing obstetric services in Israel.
A nationwide perinatal census was conducted in Israel, in which medical, social, ethnic and demographic information on all births that took place in Israel within a predefined 3-month period was collected. The present study is the first to include 22,814 births that took place in all the obstetric units in Israel. The perinatal mortality rate decreased from 23.7 in 1964-68 to 13 in 1983-84. The frequency of cesarean section deliveries almost doubled over the last decade, while the use of forceps decreased significantly and the use of vacuum extraction did not change. The rate of low birthweight, however, remained constant over the last two decades. The level of hospital care has been shown to be significantly associated with perinatal mortality. The Israeli Perinatal Census may be used to provide information needed for promoting priority objectives for pregnancy and infant health, such as improving health status, identifying risk factors, increasing public and professional awareness, and improvement in services by protecting mother and fetus.
Adult↗
Investigation of survival time of some poultry mycoplasmas.
Glucose-fermenting poultry mycoplasmas (Mycoplasma [M.] gallisepticum, M. pullorum, M. gallinaceum, M. gallopavonis) were tested in 2 experiments for their survival time at 20 degrees C and 37 degrees C on 18 different materials used on farms and in hatcheries. All mycoplasmas survived up to 16 days in egg yolk at both temperatures. On other materials, like egg shell, egg white, paper trails, feather, and others mycoplasmas generally survived 2 to 16 days at 20 degrees C. M. gallinaceum and M. gallopavonis proved more resistant to the environment than M. gallisepticum and M. pullorum.
Animals↗
Grand multiparity--a nationwide survey.
Grand multiparity has been considered to be an obstetric hazard to both the mother and the fetus. In order to evaluate this statement we analyzed the information of a nationwide survey. The delivery records of all women (22,814) attending 30 obstetric wards in Israel between November 1983 and January 1984 were analyzed and the medical and obstetric complications associated with grand multiparity were investigated. Diabetes, hypertension, malpresentations, multiple births, large-for-gestational-age deliveries and perinatal deaths were found to be significantly more common in 1,542 multiparae who had seven or more deliveries. The association between parity and age partially accounted for this observation.
Adolescent↗