Induced luteolysis in the primate: rapid loss of luteinizing hormone receptors

The molecular mechanisms involved in luteolysis are still unclear in the primate. This study aimed to investigate the effect of induced luteolysis on the ovarian luteinizing hormone (LH) receptor and the steroidogenic enzyme, 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in the marmoset monkey. Luteolysis was induced in the mid-luteal phase either directly by systemic prostaglandin F2alpha (PGF2alpha), or indirectly by LH withdrawal using systemic gonadotrophin releasing hormone antagonist (GnRHant) treatment. The LH receptor was studied by isotopic mRNA in-situ hybridization and in-situ ligand binding and 3beta-HSD expression was studied using isotopic mRNA in-situ hybridization and immunohistochemistry. Induced luteolysis was associated with a reduction in the expression of LH receptor (P < 0.0001) and 3beta-HSD mRNA, closely followed by a reduction in the LH receptor (P < 0.05) and 3beta-HSD protein concentrations within 24 h. There were no differences in the findings whether luteolysis was induced with PGF2alpha or GnRHant. This study shows that disparate mechanisms to induce luteolysis in the primate result in an identical rapid loss of the LH receptor and 3beta-HSD. In conclusion, induced luteolysis leads to rapid loss of the steroidogenic pathway in luteal cells.     

Recognition of chitin and proteins in invertebrate cuticles using analytical pyrolysis/gas chromatography and pyrolysis/gas chromatography/mass spectrometry

Flash pyrolysis/gas chromatography (py/GC) and py/GC/mass spectrometry (MS) have been utilized to characterize the cuticles of invertebrates chemically. Pyrolysis products have been identified and assigned to specific cuticular components. Acetylpyridones, acetamidofuran, 3-acetamido-5-methylfuran and 3-acetamido-(2 and 4)-pyrones are proposed as characteristic pyrolysis markers for chitin. Pyrolysis products displaying ions of m/z 70, 154, 168, 194 are thought to derive from diketopiperazine structures and provide potential markers for proteins and peptides in which proline, alanine, valine, arginine and glycine are the dominant amino acids. These products, constituting specific pyrolysis markers for invertebrate cuticles, may reflect the amino acid composition of their constituent structural proteins. The source of the various pyrolysis products of proteins has been verified by pyrolysis of reference proteins, peptides and amino acid mixtures. The presence of additional pyrolysis products related directly to histidine and catechol moieties is consistent with the chemical structure and composition proposed for arthropod cuticles based on recent work utilizing solid state 13C and 15N nuclear magnetic resonance. This study constitutes the first comprehensive chemical characterization of the pyrolysis products of invertebrate cuticles and provides the basis for future investigations requiring qualitative screening for cross-linked chitin and proteins in modern and fossil cuticles and in materials, e.g. geopolymers, that may be derived from them.     

An integrated banking network system

In 1974, the Barclays Bank computer network consisted of three separate computer centres, each serving 600 – 900 branches. In the event of a major catastrophe at any one centre, it would not have been possible to service the branches connected to it. The paper describes the Barclays Integrated Network System, which was developed to insure against such a situation. Further facilities that will be offered by the system when it is completed are also described.     

Microprocessor interfaces

The letter shows that the use of frontend logic allows microprocessor interfaces to be designed systematically and simply, using logic-free channels. Their impletnentation requires no monostables, local clocks or any other form of timing signals.     

Preparation of photochromic calcium fluoride by additive coloration

Metallurgical and Materials Transactions B - Calcium fluoride doped with certain rare earths (CaF2:RE) can be made photochromic by additive coloration,i.e., by treating CaF2:RE samples in a calcium...     

Studies on nucleotides and related compounds in plants. III. Adenine and adenosine ratios in starch from potatoes held under prescribed conditions

Adenine is the sole base and adenosine is the sole nucleoside in potato starch extracts. The levels of these metabolites remain constant in stored potato starch over several months. In starch samples obtained from potatoes under differing physiological conditions the ratio of adenine to adenosine fluctuates. When potatoes are in an active state of growth the adenosine levels in the starch are low and the ratio of adenine to adenosine is consequently high (approx 8–12). Starch from physiologically inactive potatoes has an adenine: adenosine ratio of 1.5:2.5. When potatoes are held at 0 °C the levels of adenine and adenosine in the starch fall, but there is no striking change in the ratio of these two metabolites.     

The bubble-gum school of research.

Suggests that the results of the M. E. Gordon et al (see record 1979-24931-001) article on industrial-organizational psychology could have been predicted by common sense. Practicing psychologists should reflect on or seek theories of substance, stop applying current fads, avoid shortcuts, and demand intellectual integrity rather than accept popular commercial commodities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)