An accurate stable isotope dilution gas chromatographic-mass spectrometric approach to the diagnosis of guanidinoacetate methyltransferase deficiency

A gas chromatography-mass spectrometry (GC-MS) method is described for the quantification of guanidinoacetate in different body fluids, using a two step derivatisation procedure which involves a reaction with hexafluoroacetylacetone to form a bis(trifluoromethyl)pyrimidine ring structure followed by a reaction with pentafluorobenzyl bromide. 13C2-labelled guanidinoacetate is used as an internal standard. Bis(trifluoromethyl)pyrimidine pentafluorobenzyl derivatives were separated on a polar capillary GC-column and were quantified using negative chemical ionisation mass fragmentography. The detection limit of the method is 1 pmol guanidinoacetate in a 100 microl sample. Control values were obtained for urine (53.9 +/- 25.9 mmol mol(-1) creatinine), plasma (1.08 +/- 0.31 micromol l(-1)), cerebrospinal fluid (CSF) (0.114 +/- 0.068 micromol l(-1)) and amniotic fluid (3.44 +/- 0.64 micromol l(-1)). The applicability of the method is illustrated by the determination of guanidinoacetate in urine, plasma and CSF of a patient affected with guanidinoacetate methyltransferase deficiency. In all body fluids of this patient, guanidinoacetate was highly elevated.     

An evolutionarily conserved family of Hsp70/Hsc70 molecular chaperone regulators

Heat Shock Protein 70 kDa (Hsp70) family molecular chaperones play critical roles in protein folding and trafficking in all eukaryotic cells. The mechanisms by which Hsp70 family chaperones are regulated, however, are only partly understood. BAG-1 binds the ATPase domains of Hsp70 and Hsc70, modulating their chaperone activity and functioning as a competitive antagonist of the co-chaperone Hip. We describe the identification of a family of BAG-1-related proteins from humans (BAG-2, BAG-3, BAG-4, BAG-5), the invertebrate Caenorhabditis elegans (BAG-1, BAG-2), and the fission yeast Schizosaccharomyces pombe (BAG-1A, BAG-1B). These proteins all contain a conserved approximately 45-amino acid region near their C termini (the BAG domain) that binds Hsc70/Hsp70, but they differ widely in their N-terminal domains. The human BAG-1, BAG-2, and BAG-3 proteins bind with high affinity (KD congruent with 1-10 nM) to the ATPase domain of Hsc70 and inhibit its chaperone activity in a Hip-repressible manner. The findings suggest opportunities for specification and diversification of Hsp70/Hsc70 chaperone functions through interactions with various BAG-family proteins.     

Motivation and cognitive abilities: An integrative/aptitude-treatment interaction approach to skill acquisition.

Two central constructs of applied psychology, motivation and cognitive ability, were integrated within an information-processing (IPR) framework. This framework simultaneously considers individual differences in cognitive abilities, self-regulatory processes of motivation, and IPR demands. Evidence for the framework is provided in the context of skill acquisition, in which IPR and ability demands change as a function of practice, training paradigm, and timing of goal setting (GS). Three field-based lab experiments were conducted with 1,010 US Air Force trainees. Exp 1 evaluated the basic ability–performance parameters of the air traffic controller task and GS effects early in practice. Exp 2 evaluated GS later in practice. Exp 3 investigated the simultaneous effects of training content, GS and ability–performance interactions. Results support the theoretical framework and have implications for notions of ability–motivation interactions and design of training and motivation programs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Review of Psychotherapeutic change: An alternative approach to meaning and measurement.

Reviews the book, Psychotherapeutic change: An alternative approach to meaning and measurement by Alvin R. Mahrer (1985). This small and unpretentious volume is a welcome addition to the growing number of recent publications in the field of psychotherapy research that emphasize the need for innovative and more dynamic and functional conceptualizations of the meaning and measurement of psychotherapeutic change. Despite (or perhaps because of) its provocative content, Psychotherapeutic Change is an enjoyable book to read. Mahrer's style of writing is engaging, clear, and free of the customary clinical jargon. Also refreshing is the fact that the material throughout the book comes straight from the concerns of a practitioner. Although the reader may not always agree with the author and may be annoyed by the occasional repetitiveness of some ideas, this book will prove to be a source of stimulating ideas for students, clinicians, and researchers of psychotherapy alike. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An approach to general oncology: principles and procedures

53 patients clinically suspected of having a cerebellopontine angle (CPA) lesion were examined by computer tomography (CT) with 160 X 160 matrix EMI scanner. 17 cases (32%) had tumour positive CT, of which 12 were neurinomas and 1 meningioma. 1 CT suggestive of a CPA lesion was false positive and 1 unoperated case is probably a false negative CT. Three of the eleven verified neurinomas (27%) were of the medial type originating in the angle cistern. One neurinoma protruding 1 cm into the cistern showed no contrast enhancement. 2 CT scans (3.8%) were unsatisfactory due to movements and the large size of the head. CT is valuable for the investigation of CPA pathology and the diagnostic efficiency compares favourably to other neuroradiological procedures.