New image-processing system for analysis,display and measurement of static and dynamic foot pressures

A new image-processing system, using a video digitiser with an IBM-compatible PC/AT, is developed for acquisition and processing of low-contrast, lowintensity barographic images of both feet for assessment of pressure distribution during standing and walking. Data displays, in the form of centres of pressures, isopressures contours, perspective views of pressures, grey scale image and walking pressure patterns, combined image of walking pressures, paths of centres of pressures and pressure variations with time, are developed. These have provided very useful and early information regarding the internal structural changes in the bones of the foot and sites at risk of ulcer development in leprosy subjects and enable suitable corrective orthopaedic procedures to be adopted. unitl the end of November 1990, and will then return to the Indian Institute of Technology.     

Regional Administration of Recombinant Tumour Necrosis Factor-α in Cancer, with Special Reference to Melanoma

Recombinant tumour necrosis factor-alpha (rTNFalpha) possesses the unique property of activating and selectively destroying the tumour-associated microvasculature. Systemic application of rTNFalpha has shown that the maximum tolerated dose (MTD) is 10 times lower than the efficient dose in animals. The main toxicity corresponds to the systemic inflammatory response syndrome (SIRS), with a decrease of vascular resistance and hypotension. We found that it is possible to administer rTNFalpha at 10 times the MTD in an isolated limb perfusion system, using a heart-lung machine, for advanced melanoma and sarcoma of the limbs. Our results, using the combination of high dose rTNFalpha, interferon-gamma and melphalan (TIM), produced an overall objective response rate of 100% in 2 successive studies on melanoma, with 90% and 78% complete response, respectively. In sarcoma, there was an overall response rate of 64%, with 36% complete response. Angiographic and immunohistological studies demonstrated selective and early damage of the tumour-associated microvasculature, preceded by upregulation of adhesion molecules and intratumoural leak of von Willebrand factor. Tumour invasion by platelets and, in some cases, by polymorphonuclear cells, appeared within hours after the application of rTNFalpha, long before the lysis of the tumour. Systemic changes after rTNFalpha treatment included the production of soluble TNFalpha receptors and of interleukin-6. A typical acute phase reaction was observed within 3 days, with increase of C-reactive protein parallelled by an increase of tenascin-C. A selective effect on intratumoural endothelial cells seems to be involved in the mechanism of the impressive antitumour effect of rTNFalpha, but the role of acute phase protein production is not fully understood. In selected cases of melanoma, specific cytotoxic T lymphocytes were increased after perfusion.     

Visual field deficits in cats reared with cyclodeviations of the eyes

Summary Visual fields of ten cats which had one or both eyes rotated at 8 days of age were measured by two forms of perimetry and compared to visual fields of two normal cats and of four cats with monocular rotations at 16 days, 3 months or 6 months of age. All animals showed excellent localization of visual stimuli and responded to the actual location of stimuli in space rather than to the retinal locus normally associated with that location. In cats with monocular rotations, the field of the normal eye was always normal, extending from 90 ° ipsilateral to 30 ° contralateral. Cats with rotations of one eye at 3 or 6 months of age had essentially normal fields in the rotated eye as well, while cats with surgery at 8 or 16 days had restricted horizontal fields. They responded only to stimuli in the ipsilateral hemifield; they were blind in the contralateral hemifield. Their superior and inferior visual fields were normal. The field deficits related consistently to visual field coordinates and not to the angle or direction of rotation. In cats with binocular rotations the visual field of at least one eye extended across the midline. Thus, the extent of the field depended upon sensorimotor experiences of the cat both before and after surgery. It is argued that these monocular field deficits have a central origin, not a retinal one.When tested with both eyes open, seven of 14 experimental animals did not respond throughout the visual field seen by each eye alone. The total visual field with both eyes open was less than the sum of the two monocular fields; greatest losses were most pronounced in the extreme periphery of the field ipsilateral to the rotated eye. Since changes in eye position (e.g., convergence during bincocular viewing) were not observed, it is suggested that the binocular losses indicate suppression of the deviated eye which has a central origin.All animals were tested for visual following, visually-triggered extension (placing), and visually-guided reaching. Cats which had been routinely encouraged to use the rotated eye(s) by occlusion of the other eye showed skilful performance within a few weeks after surgery as previously reported by Peck and Crewther (1975), Mitchell et al. (1976) and others. In contrast, two cats reared with both eyes open after unilateral rotation in infancy were profoundly handicapped, as previously reported by Yinon (1975, 1976).This research was supported by Grant NS 14116 from the US Public Health Service     

Comparison of Nebulised Budesonide and Prednisolone in Severe Asthma Exacerbation in Adults

Background: Short courses of oral prednisolone are used as rescue therapy for severe asthma exacerbations. This study compares nebulised budesonide or oral prednisolone, both followed by budesonide Turbohaler®, as a treatment for severe asthma exacerbations, in the absence of life-threatening features. Patients and Methods: Thirteen adults admitted to hospital were randomised to receive either nebulised budesonide (4mg 8-hourly) for 48 to 72 hours followed by budesonide Turbohaler® (1600μg twice daily for 7 days, then 800μg twice daily for 21 days) for 28 days or prednisolone (40mg daily) for 9 to 11 days followed by budesonide Turbohaler® (800μg twice daily) for 21 days. The primary efficacy variable was the change from baseline at 48 hours in forced expiratory volume in 1 second (FEV₁). Secondary efficacy variables included an assessment of symptom severity (0 = none, 1 = mild, 2 = moderate, 3 = severe). Results: Difficulties were experienced with patient recruitment in the emergency setting. The results presented are from an incomplete study. Change in FEV₁ from baseline to 48 hours was not statistically significantly different between the groups (the study was underpowered to detect a difference in change in FEV₁, as the power to detect a prespecified difference between groups was 18%). Nebulised budesonide significantly reduced the severity of wheeze after 24 hours compared with prednisolone [estimate of treatment effect = ?0.95; 95% confidence intervals (CI) = ?1.76 to ?0.15; p = 0.0336 between groups] and 48 hours (estimate of treatment effect = ?0.79; 95% CI = ?1.42 to ?0.15; p = 0.0326 between groups). Conclusion: While oral prednisolone or intravenous hydrocortisone, oxygen and bronchodilators are the mainstay of acute management in severe asthma, the results of this study suggest that nebulised budesonide may assist in regaining control of symptoms during exacerbations of asthma.     

Comparison of optical, electrical, and centrifugation techniques for haematocrit monitoring of dialysed patients

Haematocrits were measured as a function of ultrafiltration in a simulated haemodialysis circuit using bovine blood (plasma conductivity 12 mS cm-1) and hypotonic (8.6 mS cm-1) or hypertonic (16 mS cm-1) dialysates as well as in the absence of dialysate. A comparison was made between measurements by light absorption due to haemoglobin, by impedance in the blood line at 5 kHz using Hanai's model of blood conductivity, by conductivity measurements of blood samples at 1.2 kHz using a conductimeter, by centrifugation of blood samples and by calculations using fluid conservation. The validity of Hanai's model was verified to be satisfactory by direct blood and plasma conductivity measurements. In the absence of ionic transfer the impedance device underestimated the haematocrit by 5 to 7%. This underestimation reached 18% in the case of hypertonic dialysate, but this effect can be minimised if the haematocrit necessary for calibration is measured by centrifugation after 15 min of dialysate circulation when ionic balance is achieved. It was found that the optical method monitors haemoglobin concentration rather than red cell volume changes and is not affected by osmotic red cell swelling in the case of hypotonic dialysate. It can be concluded that the light absorption technique is both more accurate and more convenient to use than impedance.     

Prospects for a Vaccine in Allergic Diseases and Asthma

AbstractAllergen-specific immunotherapy is widely used to treat allergic diseases, andcurrent research is now focusing on the development of therapeutic vaccines actingon the IgE immune response following allergen challenge. The IgE immuneresponse is dependent on genetic and environmental factors; production of IgEresults from complex interactions among B cells, T cells, mast cells, basophils,surface and adhesion molecules and various cytokines. New vaccination methods under investigation involve allergen-specific ornonspecific methodology. Allergen-specific methods currently being developedinclude allergoids, passive saturation of effector cells, plasmid DNA immunisationand antigen-antibody complexes. The mechanisms of immunotherapy usingallergen-specific methods differ with the allergens and the route of immunisationused (parenteral, intranasal, sublingual, oral or bronchial). Many vaccines beingdeveloped at present comprise synthetic, recombinant or highly purified subunitantigens, which although they have increased safety may also be less immunogenic.It is hoped that the addition of adjuvants will overcome this drawback. Methods ofincreasing the dose of allergen while reducing the possibility of an anaphylacticreaction include the use of non-anaphylactic isoforms of the allergens, alteration ofthe tertiary structure of the allergens and construction of minimal allergen-derived Tcell peptides. Nonspecific approaches include humanised anti-IgE antibodies,moderation of the T(H)2 cytokine network and antisenseoligodeoxynucleotide therapy.     

Right-left correlation of the sympathetically induced fluctuations of photoplethysmographic signal in diabetic and non-diabetic subjects

Photoplethysmography (PPG) records the cardiac-induced changes in tissue blood volume by light-transmission measurements. The baseline and amplitude of the PPG signal show very low-frequency (VLF) spontaneous fluctuations, which are mediated by the sympathetic nervous system, and high correlation between right and left extremities of healthy subjects. As sympathetic neuropathy is one of the diabetic complications, the right-left correlation of the PPG fluctuations was examined in diabetic patients. The PPG signal was simultaneously measured in the two index fingers and the two second toes of 35 diabetic patients and 33 non-diabetic subjects. For each PPG pulse, the baseline and amplitude were determined, and the right-left correlation coefficients of the VLF fluctuations in the baseline and amplitude were derived. The VLF fluctuations in the baseline showed high right-left correlation, both for fingers (0.93±0.05) and toes (0.93±0.06), for the non-diabetic subjects, and significantly lower correlation (0.78±0.22 and 0.84±0.17, respectively) for the diabetic patients. Similar results were obtained for the amplitude VLF fluctuations. The right-left correlation coefficients for diabetic patients decreased with the disease duration for the toe baseline and toe amplitude fluctuations and correlated with heart rate response to deep breathing for the finger baseline and toe amplitude fluctuations. The right-left correlation coefficients of the PPG fluctuations provide a simple and convenient means for assessing the adequacy of the sympathetic nervous system function.     

Quaternion-based strap-down integration method for applications of inertial sensing to gait analysis

The proposed strap-down integration method exploits the cyclical nature of human gait: during the gait swing phase, the quaternion-based attitude representation is integrated using a gyroscope from initial conditions that are determined during stance by an accelerometer. Positioning requires double time integration of the gravity-compensated accelerometer signals during swing. An interpolation technique applied to attitude quaternions was developed to improve the accuracy of orientation and positioning estimates by accounting for the effect of sensor bias and scale factor drifts. A simulation environment was developed for the analysis and testing of the proposed algorithm on a synthetic movement trajectory. The aim was to define the true attitude and positioning used in the computation of estimation errors. By thermal modelling, the changes of bias and scale factor of the inertial sensors, calibrated at a single reference temperature, were analysed over a range of ±10°C, for measurement noise standard deviations up to σ_g = 2.5° s⁻¹ (gyroscope) and σ_a = 0.05 m s⁻¹ (accelerometer). The compensation technique reduced the maximum root mean square errors (RMSEs) to: RMSE_θ=14.6° (orientation) and RMSE_d=17.7 cm (positioning) for an integration interval of one gait cycle (an improvement of 3° and 7 cm); RMSE_θ=14.8° and RMSE_d=30.0 cm for an integration interval of two gait cycles (an improvement of 11° and 262 cm).