Age trends in the use of social and temporal comparison for self-evaluation: examination of a novel developmental hypothesis

Two studies tested the novel hypothesis that children use social comparison (SC) for self-appraisal at an earlier age than they do temporal comparison (TC). The effect of other's and of own prior outcome on performance and ability appraisal and on self-evaluative strategies was examined using simple tasks and outcome information. Results from 840 children at ages 4-8 confirmed that self-evaluative SC was similar over age. Even 4- to 5-year-olds rated themselves higher after doing better versus worse than another and explained their ratings in terms of explicit SC. Social failure undermined continuing motivation at all ages. In contrast, young children in TC conditions attended only to their last outcome, and comparisons between current and prior outcomes increased with age. Self-evaluative biases were marked at age 5-6 and for boys in SC conditions. Results clarify the role of cognitive and motivational factors in the development of SC and TC.

SAGD Comes of AGE!

Abstract

Canada's remaining resources of conventional crude oil are relatively slight and dwindling, but heavy oil and, particularly, bitumen resources are large. Their quantity approaches that of the resources of conventional oil in the Middle East. Without bitumen and heavy oil, Canada would face a growing requirement for funds to purchase foreign oil. This is already a severe problem for the United States whose large, unfavourable balance of trade stems from its need to import much of its crude oil.

Canada's success in producing bitumen by open pit mining of shallow Athabasca deposits by Suncor and Syncrude and by cyclic steaming at Cold Lake by Imperial Oil has already had a significant impact. However, although these approaches are economic, both have serious limitations.

Open pit mining is limited to shallow deposits and less than 10% of the total Athabasca resource is suitable. Also, open pit mining requires the disruption of the landscape and the handling of tonnages of tailings at least ten times greater than those of the produced bitumen. The disposal of the high clay content, "middling" stream from the hot water separation process which settles at a notoriously slow rate(1) and accumulates in tailings ponds that require prodigious areas is a severe environmental problem.

Imperial Oil's cyclic steaming has considerable environmental advantages since the reservoir solids are left in place. However, it is not a gentle process; the periodic injection of steam at pressures up to 14 MPa (2000 psi) sometimes results in well failure from the large cyclic, thermal, well-stresses. An important limitation of the process is that the recovery of the oil in place is only about 25%. Practical recovery processes for further recovery have not been defined(2). The consumption of fresh water equal in volume to the produced oil places a demand on the environment. SAGD gives a higher recovery and requires less water, less energy and fewer wells. Operation of the process is simpler than cyclic steaming because it is continuous and because of the fewer wells. Efficient recovery of heat from the produced fluids is possible and, because steam is required at a lower pressure, the cogeneration of electric power is more economic.

The SAGD Concept

Steam Assisted Gravity Drainage Process (SAGD) was introduced by the author and his former colleagues at Imperial Oil in the late 1970s(3, 4, 5). It was developed as a more systematic technique for the recovery of bitumen. The concept, shown in Figure 1, is now widely understood and is described in detail elsewhere(6, 7, 8).

It was predicted, from theory, and from scaled model experiments, that production rates of the order of several hundred to over a thousand B/day could be expected from well pairs about 500 m long; this has since been confirmed by the operation of full scale pilots-in Athabasca, in Cold Lake, in Peace River and in Lloydminster.

Essential Features of SAGD

Since gravity does not provide an adequate drive to move heated bitumens to a conventional well at an economic rate(9) horizontal production wells are used for SAGD.

The effectiveness of desmopressin in the treatment of childhood nocturnal enuresis: predicting response using pretreatment variables

OBJECTIVE

To determine the factors that predict the effectiveness of desmopressin in the treatment of childhood nocturnal enuresis.

PATIENTS AND METHOD

Sixty-six children with monosymptomatic nocturnal enuresis were treated with intranasal or oral desmopressin for a 4-week period. starting with a standard dose of 20 microg (0.2 mg oral) and increasing after 2 weeks where no progress was apparent to 40 microg (0.4 mg oral). Before treatment a range of variables (demographic, situational, enuretic history, physiological, parental attitude and child) were recorded. Three parameters of success acted as dependent variables, with stepwise linear regression models used to determine pretreatment predictors of success with desmopressin.

RESULT

Each outcome variable produced a very similar model of predictors. Success, as assessed by the most dry nights over a 14-night period, was associated with less severe enuresis before treatment, a parental belief that the child's enuresis was unstable and higher birthweight.

CONCLUSION

From the analysis, a model of arginine vasopressin release is proposed and the clinical implications of the findings addressed.

Expression cloning and biochemical characterizations of recombinant cyclophilin proteins from Schistosoma mansoni

Recombinant Schistosoma mansoni cyclophilin proteins of the A and the B subtypes (SmCYP A and B) were expressed in bacterial cells as histidine- and maltose-binding fusion proteins and also as nonfused proteins. In addition, S. mansoni CYPs were produced in Sf9 insect cells in their natural forms. Purified recombinant SmCYP B was found to possess a peptidyl-prolyl cis-trans isomerase (PPIase) activity, with a kcat/Km value of 8.2 x 10(5) M-1 s-1. The SmCYP B isoform is approximately two to three times more active than SmCYP A. SmCYP B-specific RNA appears to be more abundant in adult schistosomes than SmCYP A RNA in Northern blots. These results support the conclusion that SmCYP B represents the major schistosomal CYP. The PPIase-associated activity of both CYPs was inhibitable by the immunosuppressive drug cyclosporin A (CsA). We attempt to explain differences in PPIase activities and in CsA inhibition by examining models of the two CYPs complexed to CsA.

Which drugs benefit diabetic patients for secondary prevention of myocardial infarction? DARTS/MEMO Collaboration

Diabetic patients have increased mortality following myocardial infarction. We review the evidence for benefit in diabetic patients, of the major drug groups used as secondary prevention. Beta blockers: meta-analyses suggest a reduction in mortality of 35% with beta blockers. Diabetic patients should receive beta blockers post myocardial infarction. In many patients, the benefits of beta blockers will outweigh relative contraindications. Aspirin: meta-analyses of antiplatelet therapy in high-risk subjects have shown substantial benefits. Aspirin should be prescribed for secondary prevention. Lipid lowering with statins: subgroup analyses of the major secondary prevention trials show substantial benefits across a wide range of baseline cholesterol and LDL levels. These drugs should be prescribed as secondary prevention to patients with diabetes whose total cholesterol is > 4.0 mmol(-1). Angiotensin converting enzyme inhibitors (ACEIs): the few subgroup analyses that exist from ACEI trials suggest that diabetic and non-diabetic patients derive similar benefits. Diabetic subjects who have systolic dysfunction after myocardial infarction should receive ACEIs. Treatment combination: data exist to suggest that most of these drugs produce benefit independently.

CONCLUSION

diabetic patients benefit from secondary prevention with drug treatment as much as, or more than, non-diabetic patients.

Differential response of the human cyclin B1 promoter to inhibitors of the cell cycle in NIH3T3 cells

In this study, NIH3T3 cells stably transfected with a cyclin B1-luciferase reporter vector were utilized to investigate if cyclin B1 promoter activity is linked to either DNA replication or the activities of various cyclin-cyclin dependent kinases (cdks). Synchronized cells treated at the time of serum re-stimulation with 2 micrograms/ml of the DNA synthesis inhibitor, aphidicolin, did not display an increase in luciferase activity in comparison to control cells. When treated with aphidicolin during S phase, luciferase activity decreased. In contrast, luciferase activity increased in cells treated at the time of serum re-stimulation with 200 microM olomoucine, a cyclin-cdk inhibitor. These results indicate that (1) cyclin B1 promoter activity in NIH3T3 cells is linked to a DNA replication checkpoint control mechanism; (2) the cyclin B1 gene can be activated in the absence of functional cyclin E-cdk2, cyclin A-cdk2, or cyclin B-cdk2; and (3) cyclin B1 gene activation can occur in G1 arrested cells under conditions in which the arrest is not directly linked to inhibition of DNA synthesis.

Systemic nitric oxide synthase inhibition increases insulin sensitivity in man

1. Recent evidence shows that skeletal muscle blood flow is an important determinant of insulin sensitivity and that insulin-mediated vasodilatation is nitric oxide dependent. These results have given rise to the hypothesis that endothelial nitric oxide inhibition may decrease insulin sensitivity in humans. 2. We examined this hypothesis directly by evaluating the effects of systemic nitric oxide synthase inhibition with NG-monomethyl L-arginine (3 mg h-1 kg-1) on whole-body glucose uptake (euglycaemic hyperinsulinaemic clamp) and calf blood flow (bilateral calf venous occlusion plethysmography) in 16 healthy male subjects in a randomized, double-blind, placebo-controlled, crossover study. 3. NG-Monomethyl L-arginine infusion was associated with a pressor effect (119/61 +/- 2/2 compared with 114/58 +/- 2/2 mmHg for placebo; P < 0.001), and a negative chronotropic response (57 +/- 2 compared with 62 +/- 2 beats/min for placebo; P < 0.001). The glucose infusion rate was significantly increased after infusion of NG-monomethyl L-arginine (8.9 +/- 0.9 compared with 7.9 +/- 0.8 mg min-1 kg-1 for placebo; P = 0.002). Whole-body glucose uptake increased during the clamp, with values of 9.4 +/- 0.7 and 10.9 +/- 0.8 mg min-1 kg-1 for placebo and NG-monomethyl L-arginine respectively (P = 0.036; 95% confidence interval 0.2,2.8). NG-Monomethyl L-arginine was associated with increased calf blood flow by comparison with placebo (P < 0.05, area under curve). 4. These data show for the first time that systemic inhibition of nitric oxide synthesis increases rather than decreases whole-body glucose uptake. We suggest that the higher skeletal muscle blood flow seen after NG-monomethyl L-arginine may explain the observed increase in whole-body glucose uptake.

The role of the family system in HIV risk reduction: youths with hemophilia and HIV infection and their parents. Adolescent Hemophilia Behavioral Intervention Evaluation Project (HBIEP) Study Group

OBJECTIVE

To examine the relationship between family communication and HIV risk reduction behaviors among a multisite sample of 125 male youths (ages 12-25) with hemophilia and HIV- infection, as well as their parents.

METHODS

Participants completed self-report surveys assessing communication and attitudes regarding HIV risk reduction interventions; adolescents also provided data about their sexual behaviors.

RESULTS

Adolescents with parents who discuss sexual issues were more likely to report HIV status disclosure to sexual partners. Most parents were supportive of HIV risk reduction interventions for their adolescents, but the youths themselves tended to endorse only interventions that offered opportunities for recreational activities and socialization with peers.

CONCLUSIONS

Findings are discussed in terms of intervention implications and the need for family systems-based programs.

Are we selecting the right patients for treatment of localized prostate cancer? Results of an actuarial analysis

OBJECTIVES

To determine our accuracy in selecting patients with at least a 10-year life expectancy for aggressive treatment of localized prostate cancer.

METHODS

The medical records of 261 consecutive patients who underwent radical retropubic prostatectomy were submitted to the actuarial division of American General Life and Accident Insurance Company (AGLA) for estimation of life expectancy, excluding the diagnosis of prostate cancer. Survival curves were generated from predicted individual survivals. In patients with less than a 10-year life expectancy, AGLA provided us with the basis for assigning suboptimal survival rates.

RESULTS

The mean life expectancy for the group was 15.2 years. Two hundred ten men (80%) were projected to have a life expectancy of more than 10 years, including 27 of 55 (49%) and 4 of 8 (50%) men who were older than or equal to 70 and 75 years of age, respectively. Coronary artery disease and diabetes mellitus were the most common coexisting medical conditions that adversely affected risk as single disease entities.

CONCLUSIONS

Although clinicians do not estimate life expectancy with the scientific exactitude of an actuary, the ability to assess the patient in person and assimilate pertinent medical information in a less rigid format yields similar results. Selection of men for definitive treatment of localized prostate cancer should be based on the inherent aggressiveness of the disease and the health of the individual and should not be limited by specific age cutoffs. Populations of men undergoing radical prostatectomy are younger and healthier than those in reported series of watchful waiting for prostate cancer.

Truncated forms of the androgen receptor are associated with polyglutamine expansion in X-linked spinal and bulbar muscular atrophy

X-linked spinal and bulbar muscular atrophy (SBMA) is a rare form of motor neuron degeneration linked to a CAG repeat expansion in the first exon of the androgen receptor gene coding for a polyglutamine tract. In order to investigate the properties of the SBMA androgen receptor in neuronal cells, cDNAs coding for a wild-type (19 CAG repeats) and a SBMA mutant androgen receptor (52 CAG repeats) were transfected into mouse neuroblastoma NB2a/d1 cells. The full length androgen receptor proteins, of 110-112 kDa and 114-116 kDa for the wild-type and mutant protein, respectively, were detected by Western blotting in transfected cells. In addition, the presence of an expanded polyglutamine tract in the SBMA androgen receptor appears to enhance the production of C-terminally truncated fragments of the protein. A 74 kDa fragment was particularly prominent in cells expressing the SBMA androgen receptor. From its size, it can be deduced that the 74 kDa fragment lacks the hormone binding domain but retains the DNA binding domain. The 74 kDa fragment may therefore be toxic to motor neurons by initiating the transcription of specific genes in the absence of hormonal control. Immunofluorescence microscopy on transfected NB2a/d1 cells showed that, after hormone activation, the wild-type androgen receptor translocated to the nucleus whereas the SBMA androgen receptor was mainly localized in the cytoplasm in the form of dense aggregates with very little androgen receptor protein in the nucleus. This could explain the reduction in transcriptional activity of the SBMA mutant as compared with wild-type androgen receptor.

Does a teaching programme improve general practitioners' management of depression in the elderly?

General Practitioners have a central role to play in the management of depression in their older patients. However, studies suggest that GPs tend to underdiagnose and undermanage depression in this age group. Continuing Medical Education is an important part of helping GPs keep up to date and improve their practice. We set out to see what effect a half a day postgraduate training course had on the views and knowledge of a group of local GPs on the management of depression in the elderly. Twenty-one general practitioners attended the course and of these fifteen completed a questionnaire with clinical vignettes before and six weeks after the course. Analysis of the questionnaire and vignette data showed significant improvements in a number of areas: in particular, GPs' knowledge about antidepressant treatment increased, as did their preference for cognitive behavioural therapy out of a range of psychological treatments. This study indicates that a teaching package on depression in the elderly can improve general practitioner's management knowledge. It also suggests that old age psychiatrists can play an important part in the education of their GP colleagues. Nevertheless, further studies are needed to ensure that educational programmes make an effective impact on the underdiagnosis and undertreatment of depression in the elderly.

Angiotensin-converting enzyme gene polymorphism and cardiovascular disease

1. The crucial role played by the renin-angiotensin-aldosterone system in the cardiovascular system and the immense therapeutic potential of angiotensin-converting enzyme inhibitors and, more recently, angiotensin II receptor blocking agents, in both heart failure and post-myocardial infarction is becoming increasingly evident. Polymorphisms within the genes controlling this enzyme system are candidates for the elucidation of the pathogenesis of cardiovascular disease and this link is both intriguing and provocative. Recently, an association between a polymorphism of the angiotensin-converting enzyme gene and phenotypic expression of cardiovascular disease, namely myocardial infarction, was reported. Since then, several small case-controlled studies have confirmed an association with manifestations of ischaemic heart disease or various other cardiac end-points. However, in a large prospective study the angiotensin-converting enzyme gene conferred no appreciable risk. 2. Our aim was to review the evidence that links polymorphisms of the angiotensin-converting enzyme gene with cardiovascular disease. We searched the Medline database (1990-1997) using the key words myocardial infarction, ischaemic heart disease, angiotensin-converting enzyme and polymorphisms and performed a search of the reference citation of relevant articles. We selected clinical studies on cardiovascular disease related to the angiotensin-converting enzyme genotype. 3. Taken together, the available evidence supports the notion that the DD-angiotensin-converting enzyme genotype adversely influences specific cardiovascular diseases but appears to do so in specific geographical areas and in particular patient subgroups. It is not yet known whether it does this through an interaction with other genes or by as yet unexplained biochemical mechanisms. 4. We should regard the current data with the angiotensin-converting enzyme genotype as an intriguing clue in the pathogenesis of cardiovascular disease. However, the main factor against this potential benefit is that the impact of the DD genotype appears to be small and its clinical manifestations rather heterogeneous.

Mapping of the gene encoding the B56 beta subunit of protein phosphatase 2A (PPP2R5B) to a 0.5-Mb region of chromosome 11q13 and its exclusion as a candidate gene for multiple endocrine neoplasia type 1 (MEN1)

The multiple endocrine neoplasia type 1 (MEN1) locus has been previously localised to 11q13 by combined tumour deletion mapping and recombination studies, and a 0.5-Mb region, flanked by PYGM and D11S449, has been defined. In the course of constructing a conting, we have identified the location of the gene encoding the B56 beta subunit of protein phosphatase 2A (PP2A), which is involved in cell signal transduction pathways and thus represents a candidate gene for MEN1. We have searched for mutations in the PP2A-B56 beta coding region, together with the 5' and 3' untranslated regions in six MEN1 patients. DNA sequence abnormalities were not identified and thus the PP2A-B56 beta gene is excluded as the candidate gene for MEN1. However, our precise localisation of PP2A-B56 beta to this region of 11q13 may help in elucidating the basis for other disease genes mapping to this generich region.

Immunohistochemical nuclear staining for p53, PCNA, and Ki-67 in different histologic variants of basal cell carcinoma

BACKGROUND

Increased expression of p53 has been found in the majority of basal cell carcinomas (BCCs); however, UV-light-induced signature mutations are present in only about 50% of cases. Increased nuclear staining with an immunohistochemical marker of proliferation, proliferating cell nuclear antigen (PCNA), has been correlated with aggressive behavior in BCC.

OBJECTIVE

Our purpose was to determine whether there is any relationship between different histologic variants of BCC and their expression of p53, PCNA, and Ki-67.

METHODS

We used immunohistochemical stains for p53, PCNA, and Ki-67, in superficial-multicentric, nodular-noduloulcerative, sclerosing, infiltrative, and metatypical BCC, to determine whether the staining patterns differ in these different histologic variants of BCC.

RESULTS

Superficial-multicentric BCCs were negative for p53 in four of eight tumors. Nodular BCC showed moderately intense p53 nuclear staining with some peripheral accentuation. PCNA nuclear staining was greater than Ki-67, and PCNA-positive cells were fewer than 10% in nodular BCC. Sclerosing and infiltrative BCC showed intense p53 nuclear staining with peripheral accentuation. PCNA nuclear staining was greater than Ki-67, and PCNA-positive cells were greater than 30% in the majority of these tumors. Metatypical BCCs showed diffuse intense p53 staining. PCNA nuclear staining was greater than Ki-67, and PCNA-positive cells were greater than 30% in all tumors studied. When overlying actinic keratoses showed p53 staining, the staining did not necessarily correlate with the intensity or even the presence of positive staining in the subjacent BCC.

CONCLUSION

There are at least four distinctive patterns for staining of p53, PCNA, and Ki-67 that correlate with different histologic variants of BCC.

Regulation of macrophage gene expression following invasion by Mycobacterium tuberculosis

INTRODUCTION

Mycobacteria are intracellular pathogens which survive and grow in host macrophages. M. tuberculosis bacilli enter the macrophage via binding to several distinct cell surface molecules. Following phagocytosis, sustained intracellular bacterial growth depends on the ability to avoid destruction by macrophage-mediated host defences such as lysosomal enzymes, reactive oxygen and the reactive nitrogen intermediates. We used differential display reverse transcription polymerase chain reaction (DD RT-PCR) to identify host genes which are regulated during infection and hence which might be involved in the host-parasite cross talk.

RESULTS

Live M. tuberculosis (strain H37Rv) was used to infect Balb/c peritoneal murine macrophages. mRNA from infected and uninfected macrophages was isolated at different time intervals after phagocytosis and subjected to DD RT-PCR. Oligo dT12NV and random 10mer primers were used for PCR amplification of cDNA. Macrophage genes which appeared to be differently regulated during infection were subjected to further reamplification by PCR in order to clone and sequence them. The differential expression of the selected bands was further analysed by an RNA protection assay and a Northern blot.

RESULTS

Several differentially regulated bands were identified. One band, of 158 bp, was down regulated after infection. Sequencing of this band revealed a high level of homology (95% identity) to mouse cytochrome c oxidase subunit VIIc. The downregulation was specific for live virulent Mtb, while live BCG, heat killed Mtb and latex beads-mediated phagocytosis did not affect the transcriptional level of this enzyme.

CONCLUSIONS

The cytochrome oxidase enzyme complex of the inner mytochondrial membrane catalyzes the reaction between ferrocytochrome c and oxygen. The reaction is the terminal event in the electron transport scheme. Downregulation of cytochrome c oxidase subunit VIIc could interfere with: (1) the host apoptotic programme; or (2) the host respiratory burst.

Exclusion of linkage between schizophrenia and the gene encoding a neutral amino acid glutamate/aspartate transporter, SLC1A5

An abnormality in glutamatergic function has been hypothesized as being of etiological importance in schizophrenia. Twenty-three multiplex English and Icelandic schizophrenia families were genotyped with a polymorphic dinucleotide repeat sequence in the 3'-untranslated region of the glutamate/aspartate transporter gene called SLC1A5. Using the lod and a model-free method of linkage analysis (MFLINK), no evidence of linkage between SLC1A5 and schizophrenia was found. Our results do not support the hypothesis that SLC1A5 gene mutations or allelic variants provide a major gene contribution to the etiology of schizophrenia. However, because of the likelihood of heterogeneity of linkage in schizophrenia, there is a case for testing other pedigrees for linkage to the SLC1A5 locus. The SLC1A5 locus is one of a complex family of genes encoding neutral amino acid transporter proteins and the genetic relation between these other loci and schizophrenia has not yet been established.

Lack of evidence for close linkage of the glutamate GluR6 receptor gene with schizophrenia

OBJECTIVE

Previous research has consistently implicated genetic factors in the pathogenesis of schizophrenia. It has been hypothesized that an abnormality in glutamatergic function is of etiologic importance in schizophrenia, and therefore the glutamate receptor family of genes are potential susceptibility loci for schizophrenia. To test this hypothesis the authors sought to detect linkage between the GluR6 glutamate receptor gene and schizophrenia.

METHOD

Twenty-three English and Icelandic families containing multiple cases of schizophrenia were genotyped with a microsatellite trinucleotide repeat polymorphism localized at the GluR6 glutamate receptor locus. Lod scores, model-free linkage analysis, and extended relative pair analysis were used to test for linkage.

RESULTS

No statistically significant evidence of linkage between GluR6 and schizophrenia was found.

CONCLUSIONS

The results do not support the hypothesis that GluR6 allelic variants provide a major gene contribution to the etiology of schizophrenia in a large proportion of these pedigrees.