Convex grating types for concentric imaging spectrometers

The properties of convex gratings fabricated by electron-beam lithography are investigated. Three grating types are shown. The first is a single-panel, true blazed grating in which the blaze angle stays constant relative to the local surface normal. This grating provides high peak efficiencies of approximately 88% in the first order and 85% in the second order. The second grating has two concentric panels, with each panel blazed at a different angle. This type permits flexibility in matching the grating response to a desired form. The third type has a groove shape that departs from the sawtooth blazed profile to increase the second-order bandwidth. All these types are difficult or impossible to produce with conventional techniques. The gratings compare favorably with conventional (holographic and ruled) types in terms of efficiency and scatter. Simple scalar models are shown to predict the wavelength response accurately. These gratings allow the optical designer to realize fully the considerable advantages of concentric spectrometer forms.

Steady-state vortex-screening solitons formed in biased photorefractive media

We report the observation of steady-state photorefractive vortex-screening solitons. As a singly charged circular vortex nested on a broad beam propagates through a biased strontium barium niobate crystal, it self-traps in both transverse dimensions despite the inherent anisotropy of the photorefractive nonlinearity. When the vortex beam is a doughnut-shaped narrow beam, it breaks up into two elongated slices (with a self-defocusing nonlinearity) or into two focused filaments (with a self-focusing nonlinearity). We demonstrate the optical guidance of a probe beam in a circular waveguide induced by the self-trapped vortex.

Central alpha-adrenoceptors during the development of hypertension in rats on high and low salt intake

Our purpose was to investigate the binding characteristics of central alpha-adrenoceptors during the early stages of the development of hypertension in rats on high and low salt (NaCl) intake. We measured alpha 1-[( 3H]prazosin) and alpha 2-[( 3H]rauwolscine) binding in membranes of the hypothalamus and medulla oblongata of six groups of young Wistar-Kyoto (WKY) rats, spontaneously hypertensive rats (SHR) and subtotally nephrectomized WKY (SN) rats with mean arterial blood pressure (MAP) ranging from normotensive to hypertensive levels after 1 week of salt restriction or loading. In the hypothalamus the SN-high salt rats and both SHR groups had elevated alpha 1-number but there was no change in alpha 2-number. Moreover, MAP was positively correlated with mean hypothalamic alpha 1-number in the six groups. In the medulla oblongata alpha 1-number was unaffected. However, high salt diet influenced medullary alpha 2-binding in the opposite manner in WKY rats versus SN rats and SHR. In these latter groups the affinity was increased and the number decreased in response to high salt intake. Furthermore, a positive correlation between MAP and mean alpha 1:alpha 2 ratio existed in both the hypothalamus and the medulla of the six groups. The data suggest that hypothalamic alpha 1-binding capacity was increased in SHR due principally to a genetic condition which is mimicked by salt loading in the SN rats. Medullary alpha 2-adrenoceptors of WKY, which remained normotensive despite salt loading, responded differently to high salt intake than those of the SN and SHR, whose blood pressure rose significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Complete nucleotide sequences of Bacillus plasmids pUB110dB, pRBH1 and its copy mutants

The deletion plasmids, pRBH1 (1.5 MDa, kanamycin resistance, Kmr) and pUB110dB (1.5 MDa, Kmr), were obtained from pTB913 (2.9 MDa, Kmr, isolated from a thermophilic bacillus) and pUB110 (3.0 MDa, Kmr, from Staphylococcus aureus), respectively. All the nucleotide sequences of these deletion plasmids were determined. Replication origin regions of pRBH1 and pUB110dB contained, respectively, 63 base-pair inverted repeat and a large open reading frame, encoding RepB protein (235 amino acid residues). The nucleotide sequences were identical to each other except for one base in the center of the inverted repeat. Two copy number mutant plasmids, pRBHC3 and pRBHC7, were obtained from pRBH1. The mutation points were located at different positions in the RepB protein coding region (Gly to Asp for pRBHC3 and Gly to Glu for pRBHC7). RepB protein was shown to be involved in the copy number control of these plasmids.

Changes in the sedimentation properties of cytosolic androgen receptors associated with activation in vitro and in vivo

In cell-free systems androgen receptor (AR) labeled with (3H)DHT at 0 degrees C in the presence of 50mM molybdate remains unactivated (less than 3% binding to nuclei) and untransformed (7-8S on sucrose density gradients containing 0.4M KCl and 50mM molybdate). In the absence of molybdate, however, these complexes undergo activation and transformation even at 0 degrees C, albeit, very slowly. Incubation of unactivated, untransformed AR complexes at 18 degrees C, or at 0 degrees C in the presence of 0.4M KCl, greatly accelerated both activation and transformation. Activation and transformation are also associated with formation of high affinity (3H)DHT-receptor complexes as indicated by decreased rates of (3H)DHT dissociation from the receptor. Cytosolic AR complexes labeled with (3H)DHT in tissue slices at 37 degrees C, or in vivo, undergo rapid activation, transformation and nuclear translocation. The data suggest that activation and transformation of cytosolic AR in cell-free systems is associated with changes in the physicochemical properties of AR similar to those occurring upon hormone binding in intact cells and in vivo.

Interaction of cyproterone acetate with rat prostatic androgen receptors

We have investigated the binding of cyproterone acetate (CA) to cytosolic androgen receptors (RC) and translocation of the RCCA complex into the nucleus. In a cell-free system (3H)CA binds to cytosolic androgen receptors with high affinity (KD = 11.6 nM) and limited capacity (180-200 femtomoles/mg protein). (3H)CA, however, dissociates very rapidly from the cytosolic and nuclear androgen receptors (Rn) at 0 degree C. Incubation of RC (3H)CA at 20 degrees C increased its ability to bind to nuclei. Translocation of RC (3H)CA to nuclei of intact cells was demonstrated after incubation of prostatic tissue with (3H)CA in tissue culture medium at 37 degrees C. In vivo administration of CA to castrated rats promoted RCCA translocation but did not induce androgen receptor replenishment. These data demonstrate that CA binds to and translocates androgen receptors to nuclei without concomitant receptor replenishment.

The synthesis of ribosomal RNA and ribosomal protein and their incorporation into ribosomes in the uterus of the oestrogen-stimulated immature rat

The effect of oestrogen on the synthesis of ribosomal proteins in the uterus of the immature rat has been investigated. Stimulated synthesis peaks, at 6-7-times control levels, 12 h after a single administration of the hormone. The stimulated synthesis and incorporation of newly made proteins into ribosomal particles exhibit very similar kinetics. The incorporation of newly made rRNA into ribosomes mirrors that of ribosomal protein but lags several hours behind the peak of oestrogen-stimulated rRNA synthesis.

The effects of oestradiol-17 beta on the synthesis and modification of ribosomal proteins in the uterus of the immature rat

The effects of oestrogen on the incorporation of newly-made ribosomal proteins into the ribosomes of the immature rat uterus has been investigated. Different newly-made proteins were shown to enter ribosomes at different rates and there was some evidence that the hormone exerted differential effects. Oestradiol also stimulated the phosphorylation of ribosomal protein S6 but the effect could be explained by hormone-induced changes in the precursor pools.

Estrogen receptor heterogeneity and the relationship between estrogen receptor and the tritiated thymidine labeling index in human breast cancer

Tissue from 54 patients with breast cancer was analyzed for estrogen receptor (ER). From 38 patients, tissue from multiple tumor sites was analyzed to determine ER heterogeneity. In 13 patients (34%) both positive and negative ER values were obtained. ER negative (ER-) results were observed more frequently in metastatic lesions. In 28 patients both the ER and [3H]-thymidine labeling index (LI) were measured in the metastatic lesion. [3H]-Thymidine was administered in vivo. There was a positive correlation between ER positivity and low LI. The mean LI of 8 ER positive (ER+) tumors was 3.4 in contrast to a mean LI of 10.0 for 14 ER- tumors (p less than 0.01). LI of 6 mixed ER tumors (ER+/-) was intermediate (mean 5.7). High LI (greater than or equal to 8) was associated with decreased survival regardless of the stage of disease at the time of study. ER with LI may provide an improved basis for treatment selection.

A new procedure for the quantitation of nuclear and cytoplasmic androgen receptors

Experimental conditions for the measurement of prostatic androgen receptors occupied with unlabeled hormone are described. The assay allows quantitation of cytoplasmic and nuclear receptors occupied with unlabeled ligand by exchange with 17 beta-hydroxy-17 alpha-methyl [3H]estra-4,9,11-trien-3-one at 0 degrees C. The mercurial reagent mersalyl acid (0.2 mM) is used to promote dissociation of more than 90% receptor-bound steroid. The half-time of this reaction is 10-15 min. The reaction is reversible by addition of dithiothreitol or monothioglycerol. Treatment of the receptor with mersalyl and displacement of this reagent by thiol reagents does not alter the steroid binding affinity of the receptor or the sedimentation characteristics. Binding is measured by the hydroxylapatite procedure and all buffers contain 10 mM sodium molybdate. This assay circumvents many of the difficulties associated with conventional exchange assays performed either at elevated temperature or at 16 degrees C for 20-24 h, such as receptor degradation or incomplete exchange.

Studies on the mechanism of estradiol uptake by rat uterine cells and on estradiol binding to uterine plasma membranes

A method for the preparation of viable uterine cell suspensions is described. Using this system the kinetics of estradiol uptake were studied in order to asses whether the steroid enters uterine cells by passive diffusion (1) or protein mediated diffusion (2). The data presented show that a) the rates of estradiol entry are nonsaturable; b) temperature dependence of uptake kinetics gives a linear Arrhenius plot; c) E2-6-CMO-BSA does not inhibit 3H-E2 uptake; d) uterine plasma membranes do not contain specific estrogen binding sites. Thus, estrogen uptake occures by passive diffusion.