Techniques in facial identification: Computer-aided facial reconstruction using a laser scanner and video superimposition

A facial image was reconstructed from the skull, part of a complete skeleton found in woodland, of a male person who had hanged himself from a tree. In addition, video superimposition was carried out with antemortem photographs of a person suspected of being the victim, and a good match was obtained. In a further case, a cheaper video-transparency superimposition was carried out, with identity later being confirmed on the basis of dental records. The techniques and the problems encountered are discussed. According to our experience, 3D computer reconstruction and video superimposition have a useful role in the process of identification, particularly in the early stages of an investigation and when other more definitive methods may not be available.     

Clinical application of rapid assay of interleukin-6 in influenza-associated encephalopathy

The characteristics of influenza-associated encephalopathy is the high mortality and nimble progress with coma which appears in general cases within 48 hours. Most of patients show no abnormalities in the standard blood checks on admission or in early stage. In this study we investigated if a rapid assay of interleukin (IL)-6 is useful in influenza-associated encephalopathy in early stages. The levels of IL-6 in patients with influenza-associated encephalopathy did not show any significant difference compared with those in patients with febrile convulsion and rotavirus-associated convulsion. However the levels of IL-6 in severe cases were significantly higher than those of mild cases with influenza-associated encephalopathy. Consequently the rapid assay of serum IL-6 is useful to evaluate and decide the therapies.     

荧光定量PCR快速诊断21三体综合征

目的　建立荧光定量PCR技术检测 2 1三体综合征。方法　采用PCR方法同时扩增位于 2 1号染色体上的人肝型磷酸果糖激酶基因 (humanliver typephosphofructokinasegene ,PFKL CH 2 1)和位于 1号染色体上的人肌型磷酸果糖激酶基因 (humanmuscle typephosphofructokinasegene ,PFKM CH1) ,使用SYBRGreenⅠ荧光染料处理产物、琼脂糖电泳后在凝胶成像系统进行分析 ,得出扩增产物的荧光强度对比值。用此方法检测 2 6例 2 1三体综合征患儿及 2 0名正常人。结果　 2 6例 2 1三体综合征患儿PFKL CH2 1/PFKM CH 1扩增产物的荧光强度对比值为 1.5 8± 0 .17,而正常人为 1 0 0± 0 .0 5 ,两者差异有显著性。结论　SYBRGreenⅠ荧光定量PCR技术检测 2 1三体综合征具有准确、快速、安全、实用等特点 ,有较高的临床使用价值。     

Determination of rate-constants as a method to describe passive expiration

To describe the relaxed expiration by a two-compartment model, we introduced a gas/energy transfer between the lung compartment (V₁) and a second one (V₂). If V₂ were a real volume, the rate-constants (i.e. the flow/volume ratios) of the compartments would describe a real gas-exchange. Alternatively, if a viscoelastic behaviour of the lung or an energy-exchange between compartments was simulated, V₂ would become a "pseudo-volume". We studied nine mechanically ventilated subjects. Changes in volume were transduced by respiratory inductive plethysmography. The rate-constants were assumed (together with the initial volumes of the compartments) as parameters to fit the total volume [V₁(t)+V₂(t)]. Once the best fitting was performed using these "physiological" parameters, the system was directly identified and the compartments were independently analysed. The time profile of the second compartment showed a maximum that depended on the value of the rate-constants. Appropriate tests confirmed the reliability of our procedure. In conclusion, our analysis demonstrated that the energy/volume of the second compartment may increase at the beginning of expiration and then decrease, showing a maximum, even though the total curve can only be a decreasing one. In other words, the slowing down of the curve representing expiratory volume is due not only to the longer emptying of the second compartment, but also to the interaction between the two compartments. As presently proposed, this interaction can be represented by either a gas exchange between two actual volumes, or a mechanical energy transfer between the lung and the tissue compartment.     

Detection of neutralizing IgM antibodies in the diagnosis of enterovirus infections

Data are presented of IgM detection by a neutralization test used routinely in 1,062 patients. Antigens isolated during the period of investigation were EV4, EV7, EV11, EV18, EV21, EV24, EV33, CA9, CB2, CB4, and CB5. No difference was observed in the distribution of IgM-positive sera according to age and sex. Total antibodies are at higher titres when IgM antibodies are present. Polytypic IgM responses are not frequent (less than 10%). The frequency of the IgM-positive sera for a given serotype correlated with the frequency of isolates for the serotype except for CA9. Other than for babies under age 6 months, IgM detection is more frequent than is isolation. The susceptibility of the elderly and the frequency of IgM-positive sera among adults over age 40 years suggests possible underestimation of enterovirus infections in adults. The duration of IgM remains a major question.     

Analysis of dynamic cerebral autoregulation using an ARX model based on arterial blood pressure and middle cerebral artery velocity simulation

The study aimed to model the cerebrovascular system, using a linear ARX model based on data simulated by a comprehensive physiological model, and to assess the range of applicability of linear parametric models. Arterial blood pressure (ABP) and middle cerebral arterial blood flow velocity (MCAV) were measured from 11 subjects non-invasively, following step changes in ABP, using the thigh cuff technique. By optimising parameters associated with autoregulation, using a non-linear optimisation technique, the physiological model showed a good performance (r=0.83±0.14) in fitting MCAV. An additional five sets of measured ABP of length 236±154 s were acquired from a subject at rest. These were normalised and rescaled to coefficients of variation (CV=SD/mean) of 2% and 10% for model comparisons. Randomly generated Gaussian noise with standard deviation (SD) from 1% to 5% was added to both ABP and physiologically simulated MCAV (SMCAV), with ‘normal’ and ‘impaired’ cerebral autoregulation, to simulate the real measurement conditions. ABP and SMCAV were fitted by ARX modelling, and cerebral autoregulation was quantified by a 5 s recovery percentage R5% of the step responses of the ARX models. The study suggests that cerebral autoregulation can be assessed by computing the R5% of the step response of an ARX model of appropriate order, even when measurement noise is considerable.     

Determining appropriate models for joint control using surface electrical stimulation of soleus in spinal cord injury

The mechanical impedance of the ankle joint during electrical stimulation of the soleus is studied by applying constant-velocity 10° angular perturbations to the ankle and measuring the resultant torque. Both neurologically intact subjects and spinal cord injured subjects are tested. Lumped, piecewise linear models are developed to predict the torque from the measured displacement and acceleration signals. The commonly used second-order mass-spring-dashpot model fails to predict the changes in torque that occur following imposed movements. A fiveelement, directionally-dependent piecewise linear model is much better at predicting the measured responses for velocities up to 50° s⁻¹. Numerical least squared error indentification techniques are used to estimate the model parameters for three neurologically intact and three spinal cord injured subjects. The average error between the model’s response and the measured response across all subjects is 10·9%. There is some evidence that a velocity-dependent non-linear model could produce better results than the directionally-dependent piecewise linear model.     

Dynamic relationship between EMG and torque at the human ankle: Variation with contraction level and modulation

Stochastic system identification techniques were used to determine the dynamic relationship between the electromyogram (EMG) and torque in the ankle muscles of normal human subjects. EMG and torque were recorded while subjects modulated ankle torque by tracking a computer-generated stochastic waveform. Nonparametric impulse response functions (IRFs) relating EMG to ankle torque were computed and parameterised by determining the parameters of the second-order system which provided the best least-squares fit. Two sets of experiments were carried out. In the first, the mean level of torque was varied from 5 per cent of the maximum voluntary contraction (MVC) to 30 per cent MVC while the depth of modulation was held constant at ±5 per cent of MVC. In the second series of experiments the mean torque was held constant at 25 per cent MVC while the depth of modulation was varied from ±2.5 per cent to ±25 per cent. The major findings were: (1) A second-order, low-pass filter provided a good quasilinear model of the EMG/force dynamics under all conditions; (2) The model parameters depended only weakly on the mean level of torque; (3) In contrast, the model parameters depended strongly on the amplitude with which the contraction was modulated; the natural frequency increased significantly with the depth of modulation.     

A comparative study of the JAM test and 51Cr-release assay to assess the cytotoxicity of dendritic cells on hematopoietic tumor cells

Dendritic cells (DCs) are potent antigen presenting cells and possess a direct anti-tumor cytotoxic ability. Nevertheless, the mechanism of anti-tumor cytotoxicity by DCs and the methods for its evaluation are not fully elucidated. In order to clarify this mechanism of cytotoxicity, we examined the ability of DCs 1) to suppress [³H] thymidine (³H-TdR) uptake by tumor cells; 2) to induce cytolysis on ⁵¹Cr-labeled tumor cells; 3) and to induce DNA fragmentation on ³H-TdR labeled tumor cells (JAM test). Cytolysis and DNA fragmentation are markers of necrotic and apoptotic mechanisms of cytotoxicity in vitro, respectively. DCs inhibited approximately 38.6% to 54.8% of the growth of B4D6, NB4, U937, and Daudi cells as evaluated by the uptake of ³H-TdR. However no cytolysis was verified by ⁵¹Cr-release assay. On the other hand, cytotoxicity rates found using the JAM test ranged from 3 to 81% depending on the cell line and the effector to target cell ratio. The discrepancy of cytotoxicity between ⁵¹Cr-release assay and the JAM test may be due to the phagocytosis of apoptotic tumor cells or the absorption of released ⁵¹Cr by DCs surrounding the target cells. In conclusion, the JAM test was more sensitive than the 4-h and the 10-h ⁵¹Cr-release assay to investigate cytotoxicity mediated by DCs toward hematopoietic tumor cell lines in vitro.