Comparative study of monoclonal antibody scan in diagnosing orthopaedic infection

When clinical data are insufficient to diagnose infection of bone or joints, nuclear scanning becomes crucial in making an accurate diagnosis. The efficacy of (99m)technetium antigranulocyte monoclonal antibody Fab' fragment (LeukoScan) is prospectively compared with (111)indium white blood cell and (99m)technetium methylene diphosphonate bone scans in 74 patients with suspected musculoskeletal infections. They were grouped according to site of suspected infection: 33 long bones, 23 prosthetic joints, and 18 diabetic feet. Sixty-two of these 74 patients had surgical verification with histopathology or culture. The remaining 12 patients had clinical followup as proof of absence of infection. The overall sensitivity of LeukoScan, (111)indium white blood cell, and (99m)technetium methylene diphosphonate bone scans was 93%, 85% and 92%, respectively. Specificity was 89%, 75% and 52%, and accuracy was 90%, 79% and 74%, respectively. The conclusion from this study is that LeukoScan is more accurate in detecting osteomyelitis, with better sensitivity and specificity in prosthetic joints. Compared with (111)indium white blood cell scans, LeukoScan++ gives superior images, and results are obtained in 1 to 6 hours without biohazard risk from handling blood products.     

Quantal release at a neuronal nicotinic synapse from rat adrenal gland

The neuronal nicotinic synapse in tissue slices of the adrenal medulla was studied with whole-cell patch-clamp. Excitatory postsynaptic currents (EPSCs) were evoked by local field stimulation or occurred spontaneously especially when external [K+] was increased. EPSCs were carried by channels sharing biophysical and pharmacological properties of neuronal-type nicotinic receptors (nAChRs). A single-channel conductance (gamma) of 43-45 pS was found from nonstationary variance analysis of EPSCs. Spontaneous EPSCs were tetrodotoxin-insensitive and Ca(2+)-dependent and occurred in burst-like clusters. Quantal analysis of spontaneous EPSCs gave a quantal size of 20 pA and amplitude histograms were well described by binomial models with low values of quantal content, consistent with a small number of spontaneously active release sites. However, rare large amplitude EPSCs suggest that the total number of sites is higher and that extrajunctional receptors are involved. Our estimates of quantal content and size at the chromaffin cell neuronal nicotinic synapse may be useful in characterizing central neuronal-type nicotinic receptor-mediated cholinergic synaptic transmission.     

Diagnosis of systemic causes of uveitis; a matter of ophthalmologist and internist

OBJECTIVE: To assess how often the aetiology is established in patients with uveitis, what systemic disease are found and what is the contribution of the internist to the diagnostic process. DESIGN: Retrospective study. SETTING: University Hospital Leiden, the Netherlands. METHOD: From January 1987 to April 1992, 342 patients presented with uveitis. All patients underwent a standard ophthalmological examination. Referral to an internist and individualised laboratory screening followed in patients with recurrent, chronic, bilateral or panuveitis. Recorded were: ophthalmological data, results of laboratory screening, results of analysis by the internist, final diagnosis and presence of systemic disease. RESULTS: 149 (44%) patients were examined by the internist, 18 (5.2%) were seen by another specialist. In 169 (49%) patients a specific diagnosis was made. 74 (22%) had a systemic disease, 74 a primary ocular disease. In 28 (8%) a systemic disease was presumed (5% were HLA-B27 positive, 3% had abnormal laboratory results); 5 (1%) patients had endophthalmitis as a complication of a septic process. CONCLUSION: In approximately 1/3 of the patients with uveitis a systemic disease was found. Examination by the internist tailored to the individual patient is essential in the evaluation of uveitis patients.     

Thermal-lens and photo-acoustic methods for the determination of SiC thermal properties

In this paper we report the use of photothermal techniques such as Thermal lens (TL) spectrometry, Photoacoustic and heat capacity, ρc_p, to determine the thermo-optical parameters, such as thermal conductivity (K), thermal diffusivity (D), specific heat (c_p) and the optical path dependence with temperature (ds/dT), of an undoped polycrystalline 3C-SiC. To our knowledge, this is the first time that Thermal lens technique is used for wide band-gap systems. Results obtained for the polycrystalline sample with TL technique indicates that ds/dT is negative at room temperature. Moreover, the obtained values of thermal diffusivity and thermal conductivity are in good agreement with that found in the literature, indicating that the phototermal techniques can be used to obtain the referred parameters in circumstances where other techniques cannot be used, for example, in harsh environments.     

Learning user preferences of route choice behaviour for adaptive route guidance

As the use of navigation systems becomes more widespread, the demand for advanced functions of navigation systems also increases. In the light of user satisfaction, personalisation of route guidance by incorporating user preferences is one of the most desired features. A user model applied to personalised route guidance is presented. The user model adaptively updates route selection rules when it discovers the predicted choice differs from the actual choice of the driver. This study employs a decision tree learning algorithm, the C4.5 algorithm, which has advantages over other data mining methods in terms of its comprehensible model structure. Simulation experiments with a real-world network were conducted to analyse the applicability of the model to adaptive route guidance and the accuracy of its prediction