Effects of repeated administration of potassium canrenoate (SC-14266) on serum gonadotrophin,prolactin, testosterone and progesterone in male rats

Summary Chronic administration of potassium canrenoate (SC-14266), a water-soluble anti-aldosterone agent, increased serum LH levels in male rats without altering serum levels of FSH, prolactin, testosterone and progesterone. The increase in serum LH may be due to the anti-androgenic effect of potassium canrenoate.Acknowledgments. The authors thank the Rat Pituitary Hormone Distribution Program, NIAMDD, NIH and Dr A.F. Parlow for radioimmunoassay materials.     

Differential roles of MDA5 and RIG-I helicases in the recognition of RNA viruses

The innate immune system senses viral infection by recognizing a variety of viral components (including double-stranded (ds)RNA) and triggers antiviral responses. The cytoplasmic helicase proteins RIG-I (retinoic-acid-inducible protein I, also known as Ddx58) and MDA5 (melanoma-differentiation-associated gene 5, also known as Ifih1 or Helicard) have been implicated in viral dsRNA recognition. In vitro studies suggest that both RIG-I and MDA5 detect RNA viruses and polyinosine-polycytidylic acid (poly(I:C)), a synthetic dsRNA analogue. Although a critical role for RIG-I in the recognition of several RNA viruses has been clarified, the functional role of MDA5 and the relationship between these dsRNA detectors in vivo are yet to be determined. Here we use mice deficient in MDA5 (MDA5-/-) to show that MDA5 and RIG-I recognize different types of dsRNAs: MDA5 recognizes poly(I:C), and RIG-I detects in vitro transcribed dsRNAs. RNA viruses are also differentially recognized by RIG-I and MDA5. We find that RIG-I is essential for the production of interferons in response to RNA viruses including paramyxoviruses, influenza virus and Japanese encephalitis virus, whereas MDA5 is critical for picornavirus detection. Furthermore, RIG-I-/- and MDA5-/- mice are highly susceptible to infection with these respective RNA viruses compared to control mice. Together, our data show that RIG-I and MDA5 distinguish different RNA viruses and are critical for host antiviral responses.     

Coherent spin manipulation without magnetic fields in strained semiconductors

A consequence of relativity is that in the presence of an electric field, the spin and momentum states of an electron can be coupled; this is known as spin-orbit coupling. Such an interaction opens a pathway to the manipulation of electron spins within non-magnetic semiconductors, in the absence of applied magnetic fields. This interaction has implications for spin-based quantum information processing and spintronics, forming the basis of various device proposals. For example, the concept of spin field-effect transistors is based on spin precession due to the spin-orbit coupling. Most studies, however, focus on non-spin-selective electrical measurements in quantum structures. Here we report the direct measurement of coherent electron spin precession in zero magnetic field as the electrons drift in response to an applied electric field. We use ultrafast optical techniques to spatiotemporally resolve spin dynamics in strained gallium arsenide and indium gallium arsenide epitaxial layers. Unexpectedly, we observe spin splitting in these simple structures arising from strain in the semiconductor films. The observed effect provides a flexible approach for enabling electrical control over electron spins using strain engineering. Moreover, we exploit this strain-induced field to electrically drive spin resonance with Rabi frequencies of up to approximately 30 MHz.     

Purification of α-ketoaldehyde dehydrogenase from the human liver and its possible significance in the control of glycation

Summary Alfa-ketoaldehyde dehydrogenase, which was extracted and purified from human livers, may act on carbonyl compounds, such as 3-deoxyglucosone, and be involved in the control of glycation (Maillard reaction) in the body.     

Dopamine-beta-hydroxylase activity in stroke-prone spontaneously hypertensive rats

Dopamine-beta-hydroxylase (DBH) activity was higher in the serum, the mesenteric artery and the cerebral cortex of 4-week-old stroke-prone spontaneously hypertensive rats (SHRSP), and lower in the nucleus tractus solitarii than it was in spontaneously hypertensive rats (SHR).     

Comparison of X-prolyl dipeptidyl-aminopeptidase activity in human cerebrospinal fluid with that in serum

Summary X-Prolyl dipeptidyl-aminopeptidase activities in cerebrospinal fluid and serum from the same patients without neurological diseases, undergoing surgery under lumbar anesthesia, were assayed fluorometrically with a newly synthesized fluorogenic substrate, 7-glycylproline-4-methylcoumarinamide; the values were 129.1±19.5 nmoles/min/1 and 54.17±3.11 moles/min/1 (mean±SEM, n=23), respectively, and there was no correlation between both activities (r=0.0894).     

Studies on substrate specificity of X-prolyl dipeptidyl-aminopeptidase during new chromogenic substrates, X-Y-p-nitroanilides

Substrate specificity of X-prolyl dipeptidyl-aminopeptidase (dipeptidyl aminopeptidase IV) was examined by using newly synthesized 8 chromogenic substrates, X-Y-p-nitroanilides. Homogeneous enzyme from human submaxillary gland hydrolyzed glycylproline p-nitroanilide almost specifically, except alanylalanine p-nitroanilide which had 11% activity.