Supersmart mice: surprising or surprised? Theoretical comment on Singer, Boison, Möhler, Feldon, and Yee (2007)

The glycine transporter (GlyT1) regulates levels of the neurotransmitter glycine, a coagonist of the N-methyl-D-aspartate receptor (NMDAR), and as such may represent a novel site for developing cognition-enhancing drugs. Genetically modified mice with reduced levels of GlyT1 have been generated to test this hypothesis. P. Singer, D. Boison, H. M?hler, J. Feldon, and B. K. Yee now show, through a spontaneous exploration task, that mice in which GlyT1 has been deleted, specifically in neurons in the forebrain, demonstrate enhanced object recognition memory. Whereas both control and mutant mice show a preference for a novel object over a familiar object 2 min after the initial presentation of 1 of the objects, only the mutant mice show a preference for the novel object when tested after a 2-hr delay. The longer-lasting habituation displayed by the GlyT1 mice is consistent with a role for glycine/NMDAR-dependent synaptic plasticity in supporting a nonassociative, short-term memory trace of a recently experienced stimulus. This short-term habituation process may be independent of associative learning mechanisms and may be best described by A. R. Wagner's (1981) sometimes opponent process model.     

Genetic testing for heart disease susceptibility: potential impact on motivation to quit smoking

As genetic tests for common gene variants and multifactorial, lifestyle-related conditions become available, it will be increasingly important to determine the psychological and behavioral impact of this emerging class of genetic tests. Our aim was to examine the potential impact of genetic testing for heart disease susceptibility on psychological predictors of smoking cessation. Two hundred and sixty-one smokers were asked to imagine that they had undergone a test for heart disease risk. They were randomly assigned to a genetic test scenario (low- or high-risk result) or an oxidative test scenario (high-risk result). Smokers in the genetic test-high risk group reported greater intention to quit smoking than smokers in the oxidative test-high risk group (p = 0.009); 30% of this was mediated by their holding stronger beliefs that quitting would reduce their heart disease risk (outcome expectations) (p = 0.011). The effect of genetic test-high risk feedback on outcome expectations was greatest amongst smokers with no heart disease family history (p = 0.038). The results suggest that genetic testing for heart disease risk may enhance interventions designed to improve health via increasing smoking cessation rates. Whether the findings hold true in studies that use real rather than hypothetical genetic tests remains to be seen.     

Lip impressions: a new method for monitoring morphological changes in orofacial granulomatosis

AIM: To develop and evaluate an objective method for assessing lip size and treatment-related morphological changes in orofacial granulomatosis (OFG) patients. MATERIALS AND METHODS: Patients with swollen lips because of OFG (n=21) were enrolled. A light-body polyvinylsiloxane material was used to take lip impressions before and after treatment (n=10), or during treatment (n=11). Plaster models were cast from the impressions and the lips were measured using callipers. The intra-examiner and inter-examiner reproducibility of the technique were assessed. RESULTS: OFG patients had significantly larger lips than controls (P<0.0001). The coefficient of variation on repeated measurements of the same impression was 1.6% and for duplicate impressions was 2.6%. Significant reduction in lip size was shown in all 10 patients after diet restriction (P<0.002). Seven of 11 patients whose impressions were taken at least 3 months after the initiation of cinnamon- and benzoate-free diet also showed reduction in lip size during follow up (P<0.002). CONCLUSIONS: Serial lip impressions appear to be reliable for routine quantification of morphological changes of the lips in OFG patients. We present a new reproducible and sensitive method for assessing changes in lip size in response to treatment in OFG.     

Left ventricular relaxation and filling in hypertrophic cardiomyopathy. An echocardiographic study.

Echocardiograms showing left ventricular cavity and mitral valve cusps simultaneously were recorded in 36 patients, apex cardiograms being obtained in 26 of them. These were digitised and continuous plots made of left ventricular dimension, its rate of change, and anterior mitral leaflet velocity, and were compared with those in 20 normal subjects. Peak mitral diastolic closure rate was reduced to 120 +/- 80 mm/s, compared with normal (250 +/- 60 mm/s). Peak rate of increase of dimension was normal (13.4 cm/s), though the pattern of filling was disturbed, with the duration of rapid filling prolonged in 5, and shortened in 15, suggesting restriction. Mitral valve opening, normally synchronous with minimum dimension, was delayed by a mean of 76 ms, and during this period there was an abnormal increase in dimension. Dimension also increased by 50 +/- 25 per cent of the total diastolic excursion before the 'O' point of the apex cardiogram compared with 21 +/- 7 per cent in normals, and the timing of peak rate of increase of dimension was delayed by 50 +/- 20 ms instead of being synchronous with the 'O' point as normal. None of these findings correlated with the reduction in peak mitral diastolic closure rate. Noninvasive methods thus show that relaxation may be abnormal in hypertrophic cardiomyopathy. Delay in mitral valve opening and disturbances in the rate, duration, and co-ordination of wall movement during filling suggest the presence of segmental abnormalities of left ventricular function.     

A whole system study of intermediate care services for older people

BACKGROUND: Intermediate care (IC) services have been widely introduced in England and have the strategic objectives of reducing hospital and long-term care use. There is uncertainty about the clinical outcomes of these services and whether their strategic aims will be realised. SETTING: A metropolitan city in northern England. DESIGN: A quasi-experimental study comparing a group of older people before and after the introduction of an IC service. A quota sampling method was used to match the groups. SUBJECTS: Patients presenting as emergency admissions to two elderly care departments with falls, confusion, incontinence or immobility. Intervention: a city-wide service in which a joint care management team (multi-agency, multi-disciplinary) assessed patient need and purchased support and rehabilitation from sector-based IC teams. OUTCOMES: Nottingham Extended Activities of Daily Living score, Barthel Index, Hospital Anxiety and Depression score, mortality, readmission to hospital, and new institutional care placement at 3, 6 and 12 months post-recruitment. RESULTS: There were 800 and 848 patients, respectively, in the control and intervention groups. Clinical outcomes, hospital and long-term care use were similar between the groups. Uptake of IC was lower than anticipated at 29%. An embedded case-control study comparing the 246 patients who received IC with a matched sample from the control group demonstrated similar clinical outcomes but increased hospital bed days used over 12 months (mean +8 days; 95% CI 3.1-13.0). CONCLUSION: This city-wide IC service was associated with similar clinical outcomes but did not achieve its strategic objectives of reducing long-term care and hospital use.     

Handy heart sound simulator

A simple bedside technique of heart sound simulation using hand and stethoscope is described. The technique utilizes tissue vibration and sound conduction with the usual air column of a stethoscope to reproduce auscultatory events accurately without the distortion that often accompanies electrical production of heart sounds.     

The cytoskeleton in Chediak-Higashi syndrome fibroblasts

The Chediak-Higashi syndrome (CHS) trait is expressed in cultured human skin fibroblasts as an abnormal perinuclear concentration of moderately enlarged lysosomes. The cytoskeleton of CHS fibroblasts appears intact. Microtubules are normal in number and morphology, as assessed by colchicine binding studies, antitubulin immunofluorescence, and electron microscopy. Deformability by shear force is unaltered and microfilaments are abundant. However, CHS lysosomes appear to interact abnormally with the cytoskeleton, since the perinculear aggregation partially disperses after depolymerization of cell microtubules with colchicine. These results suggest that CHS is associated with a defect of either the lysosomal membrane itself or of lysosomal membrane- microtubule interaction.