The Wisconsin Card Sorting Test (WCST) performance in normal subjects: a twin study

The clinical medical students on the Cambridge Community-Based Clinical Course (CCBCC) derive part of their training by taking part in consultations between patients and their general practitioners. Patients' attitudes to this arrangement and their support for student training in a general practice setting are an important factor in the development of community-based education. A postal questionnaire seeking information from patients achieved an 84% response rate. Both the numerical results and the patients' comments are presented. Patients proved generally supportive of the community-based course and some identified positive benefits to themselves from this provision. The large majority of patients did not mind the presence of medical students during consultations, although there are some areas in which patients are less willing to involve students.     

Evaluation of molten pool geometry with induced plasma plume absorption in laser-material interaction zone

The presence of plasma affects laser material processing technology because, according to process parameters, a large portion of the energy emitted by the laser source is absorbed by the plasma plume without hitting the workpiece. The only way to avoid a significant reduction in process efficiency, due to plasma absorption, is thus to decrease the plasma formation by controlling the working parameters.An original analytical system for the prediction of the actual energy transmitted to the workpiece was developed by modelling the plasma plume physical state related to the process parameters. In this way, by determining the laser beam energy lost in the plasma plume and the conduction energy transmitted to the workpiece, an evaluation of the laser material interaction could be carried out.The developed model allows to evaluate the geometry of the molten pool by means of the computation of the interface between the solid and the remelted material. The effect of the plasma plume presence, by comparison with a modelisation without plasma implemented in similar way by the authors, was to reduce the molten pool and in particular the penetration depth and it permits to have close simulation results to experimental data.For the model validation several experiments were performed on an austenitic stainless steel with a CW CO₂ laser source. The experimental activity was developed by varying process speed and power level up to 1200 W when in the range of conduction welding.     

Colocalization and complex formation between prosaposin and monosialoganglioside GM3 in neural cells

Prosaposin, the precursor of saposins A, B, C, and D, was recently identified as a neurotrophic factor in vitro as well as in vivo. Its neurotrophic activity has been localized to a linear 12-amino acid sequence located in the NH2-terminal portion of the saposin C domain. In this study, we show the colocalization of prosaposin and ganglioside GM3 on NS20Y cell plasma membrane by scanning confocal microscopy. Also, TLC and western blot analyses showed that GM3 was specifically associated with prosaposin in immunoprecipitates; this binding was Ca2+-independent and not disassociated during sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The association of prosaposin-GM3 complexes on the cell surface appeared to be functionally important, as determined by differentiation assays. Neurite sprouting, induced by GM3, was inhibited by antibodies raised against a 22-mer peptide, prosaptide 769, containing the neurotrophic sequence of prosaposin. In addition, pertussis toxin inhibited prosaptide-induced neurite outgrowth, as well as prosaptide-enhanced ganglioside concentrations in NS20Y cells, suggesting that prosaposin acted via a G protein-mediated pathway, affecting both ganglioside content and neuronal differentiation. Our findings revealed a direct and tight GM3-prosaposin association on NS20Y plasma membranes. We suggest that ganglioside-protein complexes are structural components of the prosaposin receptor involved in cell differentiation.     

The rate of development and time of transfer play different roles in influencing the viability of human blastocysts

From January 1995 to September 1996, 14 isolates of Sphingomonas paucimobilis, including 11 from clinical specimens from six patients with nosocomial infection and three from environmental sources, were collected. Two of the six patients had intravascular catheter-related bacteremia and one each had bacteremic biliary tract infection, urinary tract infection, ventilator-associated pneumonia, and wound infection. The S. paucimobilis isolates were identified according to biochemical profiles established with use of the API 20NE system and Vitek GNI card and the characteristic cellular fatty acid chromatogram. Ten biotypes, 11 antibiograms (by the Etest), and 12 random amplified polymorphic DNA (RAPD) patterns (by arbitrarily primed polymerase chain reaction) were identified. The identical biotype, antibiogram, and RAPD pattern of the two isolates (one each from blood and bile) from a patient with biliary tract infection indicated the invasiveness of the organism. Two patients with intravascular catheter-related bacteremia had isolates of this organism repeatedly recovered, and these isolates had heterogeneous RAPD patterns. The present study highlights the wide distribution in hospital environments of various clones of S. paucimobilis, which may cause recurrent infections by a single strain or several episodes of infection due to two or more clones of this organism in hospitalized patients.     

Selective cardiodepressant activity of fluodipine, a fluorenone-1,4-dihydropyridine derivative

The effect of the dihydropyridine derivative, 1,4-dihydro-2,6-dimethyl-4-(fluorenon-4-yl)pyridine-3,5-dicarboxyl ic acid diallyl ester (fluodipine) was studied in vitro in different rabbit, rat and guinea pig preparations and in vivo in the rabbit in order to characterize its pharmacological profile at cardiac and at vascular sites. Compared to nifedipine, fluodipine showed a similar cardiodepressant activity, and a much lower inhibitory activity on vascular contraction. The highest tissue selectivity was observed in guinea pig preparations: fluodipine was about 2-3 times more effective than nifedipine on chronotropism and inotropism in isolated atria, and about 150 times less effective on aortic strip contraction. Accordingly, fluodipine (i) showed high-affinity binding to guinea pig ventricular L-type cardiac Ca2+ channels (Ki=2.57 nM), (ii) was about 80 times less effective than nifedipine to inhibit Ca2+ influx in vascular smooth muscle cells and (iii) induced a significant reduction of heart rate in the anesthetized rabbit (ID25=8.5 mg kg(-1), i.v.) without affecting the blood pressure up to 20 mg kg(-1), whereas nifedipine showed a significant hypotensive effect at very low doses (ID25=0.18 mg kg(-1), i.v.). The pacemaker current If of rabbit sino-atrial node myocytes was not affected by fluodipine. These findings demonstrate that fluodipine exerts selective cardiodepressant activity, likely due to a higher affinity for cardiac than for vascular Ca2+ channels.     

Structures of the (4S, 14S)-4, 14-Dimethyl-3,6,9,12,15-pentaoxa-21-azabicyclo[15.3.1] heneicosa-1(21) 17,19-Triene-2,16-dione Complexes of R-and S-α-(1-Naphthyl)ethylammonium Perchlorate

Crystal data for the more stable (R) and less stable (S) 1:1 macrocycle-cation complexes are as follows: R cation: M_r = 625.08, orthorhombic P2₁2₁2₁, a = 8.47(1), b = 11.78(1), c = 31.19(6) A, V = 3112.0(123) ų, Z = 4, D_x = 1.333 kg m⁻³, λ(Mo Kα) = 0.71073 μ = 1.90 cm⁻¹, F(000) = 1320, T = 295 K, R = 0.17 for 1680 reflections. S Cation: M_r = 625.08, monoclinic, P2₁, a = 8.654(2), b = 11.954(3), c = 15.130(4) Å, β = 97.39(2)°, V = 1552.2(12) ų, Z = 2, D_x = 1.337 kg m⁻³, λ(Mo Kα) = 0.71073, μ = 1.91 cm⁻¹, F(000) = 660, T = 295K, R = 0.081 for 2751 unique reflections. Crystals of the complexes were prepared by the authors. The greater thermodynamic stability of the R cation complex is consistent with the observation that this cation experiences less steric interaction with the methyl substituent of the ligand than does the S cation.     

Unsaturated polyester-styrene resins: Effect of the catalyst concentration on the kinetic rate and activation energy of the radical crosslinking reactions

The T₁ spin lattice relaxation time, measured by pulsed n.m.r., has been used to monitor the effect of the catalyst concentration on the kinetics of the radical crosslinking reaction of unsaturated polyester-styrene resins. The measurements were performed primarily in the intermediate-final part of the reaction under isothermal conditions. The loss of mobility of the protons of the sample has been correlated with the degree of cure and the kinetic constant as well as with the activation energy, and has been evaluated using the semiempirical kinetic expression proposed by Kamal et al. In the concentration range investigated (from 0.05 to 0.3% w/w) for the catalyst cobalt octanoate the decrease of the activation energy for the process was found to be 2.3 kcal mol^?1 of double bonds for each 0.1% w/w of cobalt octanoate.