The glucose crossover concept is not an important new concept in exercise metabolism

1. The basic premise of the 'crossover' concept (i.e. that the balance of carbohydrate (CHO) and fat utilization during exercise depends on the interaction between exercise intensity and the individual's endurance training status) has been accepted since at least the 1930s. 2. The crossover concept differs from earlier perspectives mostly in its greater emphasis on the absolute exercise intensity as an important determinant of substrate selection during exercise. Because of this emphasis, it is argued that while trained subjects may utilize less CHO than their untrained counterparts during low- or moderate-intensity exercise, this is not true during high-intensity exercise, because during such exercise even trained persons must 'crossover' to CHO dependency. In fact, the crossover concept predicts that utilization of at least one CHO source (i.e. plasma-borne glucose) should be greater in trained subjects during intense exercise. This increase in glucose utilization is hypothesized to be supported by an enhanced rate of gluconeogenesis. 3. In direct contradiction of the crossover concept, the literature consistently shows that, compared with untrained individuals, trained subjects rely less on CHO for fuel, even during high-intensity exercise. In particular, it has been shown that the rate of glucose utilization is lower in trained subjects under these conditions. Recent data from Dr Brooks' own laboratory support this conclusion and also show that this reduction in glucose use is associated with a decrease in the rate of gluconeogenesis. These recent observations confirm prior studies of moderate-intensity exercise. 4. Based on the above, it is clear that the crossover concept cannot be considered an important new concept in exercise metabolism. Instead, the crossover concept actually serves to hinder understanding in this area.     

Coming out: an overlooked concept

WITH CURRENT TRENDS in human immunodeficiency virus (HIV) early intervention moving more toward primary care, more and more advanced practice nurses (APNs) are providing primary care to people with HIV. Because almost half of new cases of acquired immune deficiency syndrome continue to have homosexual or bisexual contact as a risk factor, the APN must be prepared to address the processes that are specific to the psychosocial development of homosexual persons. The most universal of these is coming out. Coming out is a stress-inducing process that can be magnified when combined with HIV infection. Moreover, with growing recognition of the presence and needs of gay and lesbian clients in the health care system, this challenge of helping people cope with the transitions of coming out extends beyond HIV care, from adolescence through old age.     

Overconfidence: a concept analysis

Overconfidence has an effect on clinical practice and patient outcomes. The author utilizes Walker and Avant's procedure for conceptual analysis to give a systematic definition to overconfidence as it relates to decision-making in nursing. The characteristics that demonstrate the presence of overconfidence are: (a) failure to consider alternative perspectives, (b) failure to distinguish inferences from assertions, (c) favoring positive over negative information, (d) unwarranted certainty in the prediction of accuracy, and (e) control. An increased awareness of the existence of overconfidence can increase the reliability of nursing judgment.     

Lecturer practitioner: a concept analysis

The concept of the lecturer practitioner arose in one health authority in Britain in the late 1980s. Since its inception there, the concept has been widely adopted across the country suggesting that there is a perceived need for this role. However, there is much confusion over what a lecturer practitioner is, since each post is multifaceted, complex and unique. Rodgers' (1993) evolutionary concept analysis is used in an attempt to clarify and to identify those elements that are common to this concept. Through a review of all the available literature on this concept, the attributes, antecedents and consequences are identified and their implications discussed. Rodgers' evolutionary method is described and critiqued throughout the paper and is shown to be a suitable method for clarifying a complex concept.     

Antimicrobial peptides: an emerging concept in cutaneous biology

In muscle tension dysphonia (MTD) excessive tension of both the internal and external laryngeal muscles is observed. In the present pilot study, 9 pairs of surface electrodes were used to determine the electromyographic (EMG) characteristics of different muscles in the perioral area and anterior neck before and during phonation. Eleven patients with MTD and 5 normal speakers were included within the study. The results show a 6-8-fold increase of EMG activity and/or an alternation of the EMG activity level in the perioral and supralaryngeal muscles before and during phonation in most of the patients with MTD. It is not clear whether these muscles are activated as compensation for excessive tension of internal laryngeal muscles, or whether they are responsible for some of the voice disorders.     

Jóge Kankei: a key concept for an understanding of Japanese-American achievement

Jóge Kankei, or an emphasis on superior-inferior relationships, refers to the pervasive concern with ranking in Japanese society. This concept is associated with achievement motivation in that it is related to socialization practices that create in the individual a heightened sensitivity to the opinions of significant others. In this paper, the pervasive concern with ranking and the sensitivity to the opinions of others is first used as a conceptual tool to explain the alleged paradoxical behavior of the Japanese at various times in their history, and is then used as the basis of a study aimed at understanding the rapid acculturation of the Japanese Americans. The study is based upon interviews with 234 Issei (first generation, born in Japan), 241 Nisei (second generation, born of Issei parents), and 372 Sansei (third generation, born of Nisei parents). Additionally, these three groups were administered several tests and questionnaires designed to measure acculturation and the retention of Japanese values.     

Rapid platelet-function assay: an automated and quantitative cartridge-based method

BACKGROUND: The platelet glycoprotein (GP) IIb/IIIa receptor is important in mediating platelet thrombus formation, and the GP IIb/IIIa antagonist abciximab (c7E3 Fab; ReoPro) is effective in preventing thrombotic ischemic cardiovascular complications of unstable angina and percutaneous coronary interventions. Small-molecule antagonists of GP IIb/IIIa based on the Arg-Gly-Asp (RGD) sequence show similar benefit, and some of these agents are orally active. However, there may be significant interindividual variation in response to such antagonists, especially with chronic oral therapy. It will be essential to balance the beneficial antithrombotic effect of these drugs with their potential for causing bleeding. In response to this need, we have developed a rapid platelet-function assay (RPFA), a point-of-care system that provides a quantitative measure of the competence of the GP IIb/IIIa receptor as reflected in the ability of platelets to agglutinate fibrinogen-coated beads. METHODS AND RESULTS: Polystyrene beads were coated with fibrinogen and placed in a cartridge along with a lyophilized peptide that activates the thrombin receptor. Anticoagulated whole blood was added to the cartridge, and then a microprocessor-controlled operation mixed the reagents and detected agglutination between platelets and coated beads. Quantitative digital results were displayed within 3 minutes. Because there is no dilution of the blood, the assay can be used to measure platelet activity in samples that have been treated with GP IIb/IIIa antagonists with high dissociation rates. RPFA results of whole-blood samples treated with different GP IIb/IIIa antagonists correlated well with both conventional turbidimetric platelet aggregation (r2=0.95) and the percentage of free GP IIb/IIIa molecules in the sample (r2=0.96). The mean difference in measurements between RPFA and aggregometry was -4% (+/-4% SD), and the mean difference in measurements between RPFA and free GP IIb/IIIa receptors was -2% (+/-6% SD). CONCLUSIONS: The RPFA provides rapid information on platelet function that mirrors turbidimetric platelet aggregation and reflects GP IIb/IIIa receptor blockade.     

Neurogenically mediated cystitis in rats: an animal model

PURPOSE: Pseudorabies virus (PRV) is a useful tool for mapping the control circuitry of the spinal cord. In the process of mapping CNS regulatory pathways for the lower urinary tract, a hemorrhagic change in the bladder was observed that was not overtly evident in other pelvic organs. The relationship between the appearance of hemorrhagic changes in the bladder and the evolution of PRV induced changes in the spinal cord was therefore explored. MATERIALS AND METHODS: Sprague-Dawley rats were injected with PRV into the ACD tail-muscle. Bladder and CNS fixation were achieved by transcardial perfusion with formaldehyde. Multi-level sections were obtained from T8 through S4. Fixed tissue was stained and evaluated by light microscopy. Immunohistochemical stains were carried out for PRV and iNOS on spinal cord tissue. We were therefore able to evaluate the relationship between the manifestation of the hemorrhagic cystitis, appearance of the PRV in the spinal cord and evidence of CNS inflammation. RESULTS: The evolution of hemorrhagic cystitis paralleled the evidence of inflammation in the thoraco-lumbar and sacral cord. These bladders contained 5 to 9 ml. of bloody urine (a normal rat bladder contains 1 to 2 ml.). On cystomanometry (CMG) the bladders were acontractile. No PRV could be cultured in the hemorrhagic bladders. The histological changes observed in the bladder represent true inflammation. CONCLUSION: There was no obvious explanation for these changes other than the associated inflammatory changes in the spinal cord. The findings are consistent with the hypothesis that a spinal cord stress, via an unknown metabolic pathway, can result in dramatic, neurogenically mediated changes in the bladder.     

"Aggrecanase" activity is implicated in tumour necrosis factor alpha mediated cartilage aggrecan breakdown but is not detected by an in vitro assay

An accurate analysis of the morphological changes which take place during pathological processes of the posterior pole is important for a correct diagnosis and therapeutic approach. The purpose of the study was to determine the intraobserver and interobserver reproducibility of the Image-net system 100 (Topcon, Japan) to take measurements on the retina. The program 'Linear/Areal Measurement functions' of Image-net system 100 which is an image digitalization technique, was tested. Twelve patients were consecutively selected from the patients of the Retina Center of the Department of Ophthalmology, University of Genoa. Three images of each eye were taken from each subject and only the best image was used in this study. The intraobserver and interobserver reproducibility of both the distance between two pre-set points (linear measurement), and the perimeter and area of preselected retinal zones were calculated. The repeatability (or intraobserver reproducibility) of the linear sizes was measured by the coefficient of variation and ranged from 0.32% to 7.38%, while the interobserver reproducibility ranged from 0.46% to 5.22%. The repeatability and reproducibility of the perimeters ranged from 0.72% to 9.63% and from 0.6% to 5.7%, respectively, while the repeatability and reproducibility of the areas ranged from 0.72% to 9.63% and from 0.6% to 5.7%, respectively. Although the results were quite good, the quality of the image of the fundus and the number of observers influenced the coefficient of variation; furthermore, the anatomy of the areas to be measured and the computer 'mouse' could increase the value of the coefficient of variation.