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.     

The WISC may not be a valid predictor of school performance for primary-grade minority children

In the present investigation we studied the validity of the Wechsler Intelligence Scale for Children (WISC) for predicting several criterial teachers' ratings for primary-grade black, Anglo, and Mexican-American children. The results were rather striking: although validities for the combined groups were good (rs near .6), the validities calculated within each group presented a different picture. Validities were good for the Anglo children but near zero for the black and Mexican-American children. These results suggest that the WISC may be of little value in the assessment of the educability of minority children. The implications of these results for educational placement and the heredity-environment controversy were discussed.     

"Gentlemen, this is not a humbug". The 150th anniversary of anesthesia

On 16 October 1996 it was 150 years since William T.G. Morton performed the first successful demonstration of ether anaesthesia in the Massachusetts General Hospital, Boston, USA. Controlling the pain caused by surgery had been a problem for a long time. In fact, many chemical agents with pain relieving properties were recognized before they were used in practice. Morton started systematic studies on the anaesthetic effects of ether and convinced the medical world of the importance of pain free operations through his demonstration of ether inhalation. The news about ether anaesthesia spread around the world very quickly. The first ether anaesthesia administered in Norway took place at Rigshospitalet in Christiania on 4 March 1847. The first death from anaesthesia in Norway occurred in 1852. This article presents some aspects of both the Norwegian and international history of anaesthesia.     

The inverse base-rate effect is not explained by eliminative inference.

The inverse base-rate effect is a phenomenon in which people learn about some common and some rare outcomes and in subsequent testing people predict the rare outcome for particular sets of conflicting cues, contrary to normative predictions (D. L. Merlin & S. M. Edelson, 1988). P. Juslin, P. Wennerholm, and A. Winman (2001) suggested that the effect could be explained by eliminative inference, contrary to the attention-shifting explanation of J. K. Kruschke (1996). The present article shows that the eliminative inference model exhibits ordinal discrepancies from previously published data and from data of 2 new experiments. A connectionist implementation of attentional theory fits the data well. The author concludes that people can use eliminative inference but that it cannot account for the inverse base-rate effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The inverse intensity effect is not lost with stimuli in apparent motion

The inverse relationship between the visible persistence of a briefly presented stimulus and its intensity is well established for static displays. However, with non-static displays, this relationship is only partially reported by previous studies. In order to clarify this topic, we investigated the effect of luminance on the visible persistence of a stimulus in apparent motion. Assuming that persistence duration is a normally distributed random variable, we studied whether the mean persistence of a stimulus could be systematically varied by varying its luminance. Our paradigm permits evaluation of this effect without changing the temporal interval between two successive presentations of the stimulus, thus avoiding the potential influence of this latter factor on persistence. Our results show that the inverse intensity effect still occurs at each of the successive locations of a stimulus in apparent motion. In addition, we provide evidence that increasing the spatial separation between the successive presentations, and decreasing the background luminance, result both in longer persistence duration. Altogether, these findings favour the hypothesis that persistence is actively suppressed by inhibitory interactions between adjacent neural zones.     

The revelation that the revelation effect is not due to revelation.

The revelation effect is the tendency to call an item on a recognition test "old" if it is preceded by a different task interpolated between study and test. Seven experiments explored the generality of the revelation effect across a number of interpolated tasks. A revelation effect emerged when a variety of tasks preceded recognition test items; the effect was found for test items that followed a memory-span task, a synonym-generation task, and a letter-counting task. The compatibility between the test stimuli and the stimuli that composed the interpolated task was found to be a critical factor. With words as stimuli on a recognition test, a revelation effect was found when the stimuli in the interpolated task were words and letters. However, when numbers were the stimuli in the interpolated task, no revelation effect was found. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The concept of "compensation neurosis" in psychiatric expertise

The concept of "compensation neurosis" in German civil and social law is subject to controversial considerations. Despite long-standing discussions it still remains unclear, whether "compensation neurosis" means a genuine psychiatric disorder, or whether it merely stands for a person who claims unjustified demands after having suffered a traumatic situation. The term "compensation neurosis" therefore is not to be used as a diagnosis in psychiatric expertise. Diagnosis should be made according to ICD-10 or DSM-IV-criteria. The patient's psychic and psychosocial impairments must be related to the severity of his trauma and to the history of his pretraumatic and posttraumatic psychic symptoms. To help estimate posttraumatic financial compensation a complete psychopathological and psychodynamic examination with detailed assessments of individual psychic impairments is essential in psychiatric expertise.     

Allograft "acceptance" and tolerance: a new concept

Discovery of microchimerism in kidney and liver transplantation provided an important framework for a better understanding of allograft acceptance, for analysis of management problems and for therapeutically oriented transplanted research. In these new concept correlations with infectious diseases caused by non cytopathic microorganisms, previous enigmas, immunologic reaction, counter argument and general immunologic implications are discussed.     

Preceptorship: is it a workable concept?

Preceptorship has many advantages to offer newly graduated nurses. The author of this article warns, however, that the mistakes made in mentorship should be heeded and its use in practice evaluated thoroughly before it is adopted without question.     

Cerulein-induced changes in plasma amino acid concentrations are not a valid test for pancreatic insufficiency

OBJECTIVES: There is controversy about the cholecystokinin (CCK)-induced decrease of plasma amino acids for the diagnosis of pancreatic insufficiency in that it is unclear whether the conflicting results are due to different degrees of stimulation by CCK. We have therefore evaluated the amino acid consumption test by examining the dose-response relation among increasing doses of cerulein and plasma amino acids compared with the release of pancreatic polypeptide in six healthy volunteers and six patients with severe pancreatic insufficiency proven by a pathological para-aminobenzoic acid test. METHODS: Stepwise increasing doses of cerulein (10-80 pmol/kg/h) were given i.v., each for 60 min with a secretin background (1 CU/kg/h). In the volunteer group, an additional experiment with infusion of placebo (saline 0.9%) was performed. RESULTS: CCK-induced amino acid changes were small in volunteers (maximum decrease: 8.4 +/- 0.9%; mean +/- SEM), tended to be more pronounced in patients (maximum decrease: 13.8 +/- 2.8%; NS), and did not permit a distinction among volunteers and patients. There was no dose-response relationship between CCK and plasma amino acids in either group. In contrast, pancreatic polypeptide levels increased markedly and dose-dependently in volunteers and patients and tended to be lower in patients with pancreatic insufficiency. CONCLUSIONS: The decrease of plasma amino acid levels in response to cerulein does not reflect pancreatic function and does not permit the diagnosis of pancreatic insufficiency.     

The "race" concept in smoking: a review of the research on African Americans

This paper presents an analysis of the "race" concept as used by researchers who have studied the smoking behavior of African Americans. Most researchers in the field have failed to address the conceptual dimensions and meanings of "race" and accept uncritically the use of the term. This practice is viewed as an impediment in explaining inter- and intra-racial group differences and intervening effectively to reduce consumption of tobacco products. Adopting the majority-minority intergroup relations paradigm, the conceptual and practical meanings of "race" are reviewed by focusing on the history of relations between blacks and tobacco, conceptions of "race," "biology" and cigarette smoking, and the sociological nucleus (e.g. social class, racism and culture) of "race." Genetic or biologic assumptions and meanings of "race" in research on the smoking behavior of African Americans are critically examined. It is argued that "race" is a dynamic social construct reflecting societal transformations in relations between racially classified social groups (RCSGs).     

The thymidine kinase/ganciclovir-mediated "suicide" effect is variable in different tumor cells

The herpes simplex virus thymidine kinase (HSV-TK) converts ganciclovir (GCV) into a toxic product and allows selective elimination of TK+ cells in vitro and in vivo. It is currently being used in clinical gene therapy trials as a therapeutic gene or as a safety marker. We have analyzed the susceptibility of different tumor cell lines to the TK/GCV-mediated "suicide" effect. Therefore, tumor cells TSA, J558L, EB, and ESB and, as a control, NIH-3T3 cells were infected with a retrovirus containing a hygromycin/TK fusion gene. All cell lines were sensitive to GCV in vitro; however, the concentration of GCV and the time needed to eliminate tumor cells completely considerably varied between different tumor cell lines. TSA-TK cells were completely eliminated within 10 days in 1 microg/ml GCV, whereas ESB-TK cells required 22 days in 10 microg/ml GCV. When two cell lines were examined, the differing sensitivity to GCV in vitro correlated with the ability to eradicate TK+ tumors in vivo. TSA-TK tumors could be eliminated in almost all animals by systemic GCV administration, whereas ESB-TK tumors were completely resistant. Different sensitivity to GCV was not due to different TK expression levels because the cells were similarly resistant to hygromycin, and Western blot analysis with an anti-TK antiserum revealed similar protein amounts in TSA/TK and ESB-TK cells. Together, the results demonstrate that tumor cells are highly different concerning the susceptibility to the TK/GCV effect, which, however, may be tested for in vitro.