Antifreeze proteins bind independently to ice

It has been suggested that cooperative interactions between antifreeze proteins (AFPs) on the ice surfaces are required for complete inhibition of ice crystal growth. To test this hypothesis, a 7-kDa type III AFP was linked through its N-terminus to thioredoxin (12 kDa) or maltose-binding protein (42 kDa). The resultant 20-kDa and 50-kDa fusion proteins were larger in diameter than free AFP and thus precluded any extensive AFP-AFP contacts on the ice surface. Both fusion proteins were at least as active as free AFP at virtually all concentrations tested. By these criteria, AFPs function independently of each other and do not require specific intermolecular interactions to bind tightly to ice.     

"Direct Measurement of Differential Cognitive Deficit in Acute Schizophrenia": Erratum.

Reports an error in the original article by J. N. Deluca (Journal of Abnormal Psychology, 1967[April], Vol 72[2], 143-146). The author's affiliation on page 143 should read as follows: "290 Madison Avenue, Morristown, New Jersey. (The following abstract of this article originally appeared in record 2005-09867-003). This is a longitudinal study in which 11 standardized test of cognitive function were administered to 20,000 normal Ss and at a later point in time readministered to those Ss of the original group (N=15) who became schizophrenic and were hospitalized. The tests were also readministered to part of the original group (N=40) who, at the same point in time, were still normal. The results, which revealed significant differential deficit on 5 of the measures, suggest that lack of motivation to reach out and actively manipulate stimuli or experience new learning produced the differences observed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identification of a new all-trans-retinol metabolite produced through a new retinol metabolic pathway

In vitro incubation of all-trans-retinol (atROL) with kidney homogenate from vitamin A-deficient and retinoic acid-supplemented (VAD-RAS) female rats produces a new retinol metabolite. Reverse-phase (RP) and normal-phase (NP) high-performance liquid chromatography (HPLC) analysis showed that this metabolite coelutes with the unknown all-trans-retinol (atROL) metabolite previously found in the day 10 conceptus and kidneys of vitamin A-deficient rats maintained on all-trans-retinoic acid (VAD-RA) and given 2 microg of [3H]atROL. Normal-phase (NP) HPLC purification of the metabolite collected from a RP HPLC column further separated the radiolabeled material into two components. The two isolated compounds have identical or very similar spectroscopic properties. Their nuclear magnetic resonance (1H NMR) and mass spectra (MS) indicated that they are isomers. Spectroscopic studies of the metabolites and their derivatives showed that they are nine-carbon fragments resulting from an oxidative cleavage of the side chain of atROL. The cleavage occurs at C-9, and the product is then oxidized to a keto group. The primary hydroxy group from atROL is preserved in the metabolite. A sulfide bridge is formed between C-11 and C-14, which interrupts the conjugation. The formation of the new metabolites, possessing a 2,5-dihydrothiophene ring, is catalyzed by an enzyme(s) located in the cytosolic fraction of kidneys. The process represents a new retinol metabolic pathway; however, its biological significance is unknown.     

The professional/technician model in clinical neuropsychology: Deployment characteristics and practice issues.

The use of the professional/technician model or, more specifically, the laboratory method in clinical psychology and clinical neuropsychology, dates back to the 1940s. The advantages of this method are thought to include objective data collection, more efficient use of the psychologist's time, and cost-effectiveness. This article investigates some of the characteristics of technician deployment, including an analysis of differential practices of neuropsychologists using technicians vs those who do not, along with a demonstration of the efficiency and cost-effectiveness of the professional/technician model. The results indicate that the use of technicians by neuropsychologists continues to be widespread, and differences between neuropsychologists using technical personnel and those who do not are limited to the number of patients assessed per month and the amount of time allotted for assessments. Increased efficiency and cost-effectiveness is also associated with use of neuropsychology technicians. The implications of these results are discussed within the context of suggestions supporting further proliferation of this practice model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mediation of calcium adaptation by 1,25-dihydroxycholecalciferol

Vitamin D-depleted chicks which were repleted with 25-hydroxycholecalciferol adapted to the feeding of a low or high calcium diet by respectively increasing or decreasing their rate of intestinal calcium absorption. The synthesis of 1,25-dihydroxycholecalciferol in chicks fed differing calcium diets correlated directly with intestinal calcium absorption activity, suggesting that the intestinal calcium adaptation response is mediated by the modulation of kidney 25-hydroxycholecalciferol-1-hydroxylase activity. This view was strongly supported by the demonstration that repletion of the chicks with 1,25-dihydroxycholecalciferol eliminated the ability of the chicks to adjust their rates of intestinal calcium absorption to dietary levels of calcium.     

Impact of prepartum dietary phosphorus intake on calcium homeostasis at parturition

A study was conducted to determine the impact of dietary P intake on vitamin D metabolism and incidence of parturient paresis in aged dairy cows. Thirty dairy cows (10/group) were fed one of three experimental diets for approximately 28 d precalving. Phosphorus intake was .7, 1, or 3 times daily maintenance requirement and Ca intake was three times daily maintenance requirement for all cows. There was a 20% incidence of parturient paresis in each group. Prepartum dietary P intake had no effect on precalving or calving plasma Ca concentrations. Cows fed the low P (.7 times) diet had higher plasma Ca at 3 and 5 d postcalving than did cows fed P at 1 or 3 times maintenance. Plasma phosphorus concentrations reflected dietary P intake. Dietary P intake had no effect on plasma Mg, free hydroxyproline, 1,25-dihydroxyvitamin D, or 24,25-dihydroxyvitamin D concentrations. The range in dietary P from .7 to 3 times maintenance requirement had no effect on the incidence of parturient paresis. However, it did appear to influence Ca homeostasis during the postpartum period as cows fed the low P diet had higher plasma calcium concentrations postcalving. This may be a result of the low P diet enhancing intestinal C absorption by a vitamin D-mediated transport mechanism.     

MicroRNA-449a Inhibits Triple Negative Breast Cancer by Disturbing DNA Repair and Chromatid Separation

Chromosomal instability (CIN) can be a driver of tumorigenesis but is also a promising therapeutic target for cancer associated with poor prognosis such as triple negative breast cancer (TNBC). The treatment of TNBC cells with defects in DNA repair genes with poly(ADP-ribose) polymerase inhibitor (PARPi) massively increases CIN, resulting in apoptosis. Here, we identified a previously unknown role of microRNA-449a in CIN. The transfection of TNBC cell lines HCC38, HCC1937 and HCC1395 with microRNA-449a mimics led to induced apoptosis, reduced cell proliferation, and reduced expression of genes in homology directed repair (HDR) in microarray analyses. EME1 was identified as a new target gene by immunoprecipitation and luciferase assays. The reduced expression of EME1 led to an increased frequency of ultrafine bridges, 53BP1 foci, and micronuclei. The induced expression of microRNA-449a elevated CIN beyond tolerable levels and induced apoptosis in TNBC cell lines by two different mechanisms: (I) promoting chromatid mis-segregation by targeting endonuclease EME1 and (II) inhibiting HDR by downregulating key players of the HDR network such as E2F3, BIRC5, BRCA2 and RAD51. The ectopic expression of microRNA-449a enhanced the toxic effect of PARPi in cells with pathogenic germline BRCA1 variants. The newly identified role makes microRNA-449a an interesting therapeutic target for TNBC.