Prefrontal cortex and caudate nucleus in conditional associative learning: Dissociated effects of selective brain lesions in rats.

Rats with lesions to prefrontal cortex (PFC) or caudate nucleus (CN) were compared on tests of conditional associative learning (CAL) that placed varying demands on conditional rule learning and working-with-memory operations that are essential for response selection. Damage to either structure impaired performance, but the respective deficits resulted from disruption of different processes. CN lesions produced a consistent learning deficit that was thought to reflect a basic impairment in forming stimulus-response (S-R) associations. The behavior of PFC rats was more variable and depended on task requirements. When S-R learning or response selection was relatively easy, the PFC was not critical. However, when either component was made more difficult, thus requiring the contribution of strategic processes, PFC damage produced profound impairments. In addition to clarifying the roles of the PFC and CN in CAL, the results provide further evidence that multiple brain regions participate in relatively simple behavioral tasks and that their respective contributions can be dissociated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the future of the speciality of Obstetrics and Gynecology. A Dutch view

Between 4 and 15 ng/ml serum prostate-specific antigen (PSA) has a low specificity for prostate cancer (PCa). One accepted method to enhance this specificity is transrectal ultrasonography (TRUS)-measured PSA-density (PSA-D). We compared this method with a new alternative, transition zone PSA (PSA-TZ). We measured total and transition zone prostatic volumes by TRUS and calculated PSA-D and PSA-TZ in 59 patients with suspicion of PCa and PSA between 4 and 15 ng/ml. All patients then had sextant biopsies of the prostate, 30 were positive for PCa and 29 showed benign tissue. With a cut-off value of 0.35, PSA-TZ had a positive predicted value of 77% for PCa, whereas PSA-D, with a cut-off value of 0.12, had a positive predicted value of 55%. Our data suggest PSA-TZ to be more reliable for avoiding unnecessary biopsies in patients with PCa suspicion and serum PSA below 15 ng/ml. PSA-TZ, calculated by TRUS, enhances the specificity of PSA for needle biopsy diagnosis of PCa.     

The effect of imagery on explicit and implicit tests of memory in young and old people: A double dissociation.

Examined the effect of imagery on implicit and explicit tests of memory in young and old adults. 48 undergraduates (mean age 21 yrs) and 64 adults (mean age 72.48 yrs) in Canada were presented with 2 separate word lists in a random order and were assigned to imagery or no-imagery instruction conditions. Ss in the imagery instruction condition read the words to themselves, formed a mental image of it, and rated their ability to do so. Ss in the no-imagery instruction condition simply read the words. All Ss were tested on explicit or implicit memory tests and asked to describe the mnemonic strategies used. Results show that imaging the referent of a visually-presented word improved the performance of the young Ss on the explicit memory test, but reduced their performance on the implicit test. Results of the elderly Ss showed a similar trend but did not reach the level of significance observed for young adults. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transposition of group II intron aI1 in yeast and invasion of mitochondrial genes at new locations

Intron mobility at the RNA level by splicing reversal at allelic (homing) and non-allelic locations (transposition) has been reported in vitro. In the living cell, however, only intron homing by unidirectional gene conversion has been described. Supposing that intron insertions at non-allelic sites might occur in vivo, we speculated that group II splice-site-associated macro-deletions in fungal mitochondrial DNA might result from group II intron transposition to new locations followed by recombination. We used polymerase chain reaction techniques to detect this critical, infrequent intermediate in mtDNA populations. Here we report on group II intron aI1 transposition to non-allelic, splicing-compatible locations within the cox1 gene of yeast mtDNA. The identified integration sites are preceded by motifs similar to the upstream exon A1. Sequences flanking intron aI1 are not co-converted to the insertion sites and cis- and trans-acting mutations within aI1 reduce intron mobility below detection levels. These findings suggest the involvement of an RNA intermediate in group II intron transposition.     

Marked point process framework for living probabilistic safety assessment and risk follow-up

We construct a model for living probabilistic safety assessment (PSA) by applying the general framework of marked point processes. The framework provides a theoretically rigorous approach for considering risk follow-up of posterior hazards. In risk follow-up, the hazard of core damage is evaluated synthetically at time points in the past, by using some observed events as logged history and combining it with re-evaluated potential hazards. There are several alternatives for doing this, of which we consider three here, calling them initiating event approach, hazard rate approach, and safety system approach. In addition, for a comparison, we consider a core damage hazard arising in risk monitoring. Each of these four definitions draws attention to a particular aspect in risk assessment, and this is reflected in the behaviour of the consequent risk importance measures. Several alternative measures are again considered. The concepts and definitions are illustrated by a numerical example.     

Is the common 677C-->T mutation in the methylenetetrahydrofolate reductase gene a risk factor for neural tube defects? A meta-analysis

In both jurisdiction and medical science, given conditions require appropriate intervention, which may in turn result in norms being created. Norms, however, counteract individuality. An essential prerequisite for free decision--making is an absolute awareness of all possibilities available. Therefore the physician/surgeon too, is obliged to impart all relevant information to the patient prior to an operation to enable the patient to reach a decision, either to agree to or refuse the operation. This process of information transfer may sometimes fail on one or both sides. Treatment errors are usually classified according to scientific medical practice. In the case of "breach to duty in information patient" the final decision is the judges. As judicial decisions are not foreseeable, the communication between patient and surgeon thus becomes standardized and doctors tend to become defensive, resulting in the information becoming even more extensive covering all possible situations. There is no guarantee of success in surgery. Selective perception on the part of the patient is unavoidable and confidence in the relationship between patient and surgeon is beneficial to the patient's rehabilitation. Therefore, we should strive to decriminalize the preoperative talk held between surgeon and patient.