A new gait analysis system for clinical use in a rehabilitation center

A semi-portable system based on a microcomputer has been developed to measure the vertical reaction forces on both feet during walking. Eight capacitive force transducers are attached to each sole of the patients' shoes. This allowed the forces to be measured for several consecutive steps during a walk of 20 sec. This article describes the principles of operation of the force transducers and the associated electronic system. It also shows data processing procedures and gives a review of the available methods of data presentation. Recordings of the walking pattern of three patients with different diagnostics are presented and discussed to demonstrate the usefulness of the new gait analysis system in a rehabilitation center.     

Population-based prevention of influenza in Dutch general practice.

BACKGROUND: Although the effectiveness of influenza vaccination in high-risk groups has been proven, vaccine coverage continues to be less than 50% in The Netherlands. To improve vaccination rates, data on the organizational factors, which should be targeted in population-based prevention of influenza, is essential. AIM: To assess the organizational factors in Dutch general practice, which were associated with the influenza vaccination rate in 1994. METHOD: A retrospective questionnaire study was undertaken in 1586 of the 4758 Dutch general practices, which were randomly selected. A total of 1251 (79%) practices returned a questionnaire. The items verified were practice profile, urbanization, delegation index, use of computer-based patient records, influenza vaccination characteristics and influenza vaccination rate. RESULTS: No differences were found with regard to the percentage of single-handed practices (65%), practices situated in urban area (38%), practices with a pharmacy (12%), patients insured by the National Health Service (59%) and use of computer-based patient records (57%) when compared with national statistics. The mean overall influenza vaccination rate was 9.0% (SD 4.0%). Using a logistic regression analysis, a high vaccination rate (> or = 9%) was associated with the use of personal reminders (odds ratio (OR) 1.7, 1.3-2.2), monitoring patient compliance (OR 1.8, 1.3-2.4), marking risk patients in computer-based patient records (OR 1.3, 1.0-1.6), a small number of patients per full-time practice assistant (OR 1.5, 1.1-1.9), urban areas (OR 1.6, 1.3-2.1) and single-handed practices (OR 1.5, 1.1-1.9). CONCLUSION: Improvement of vaccination rates in high-risk patients may be achievable by promoting the use of personal reminders and computer-based patient records, as well as monitoring patient compliance. In addition, the role of practice assistants with regard to preventive activities should be developed further. Practices situated in rural areas and group practices may need more support with a population-based approach for the prevention of influenza.     

Spontaneous alpha peak frequency predicts working memory performance across the age span.

Working memory capacity has been consistently shown to decline with increasing age. Mechanisms underlying this decline are poorly understood. One index that has been found to predict performance on memory tests is alpha peak frequency, the peak of spectral alpha power of the EEG. Activity in the alpha band has been also associated with higher cognitive functions including attention and anticipation and has been shown to slow with age. Few studies, however, have examined whether there might be a relationship between WM decline and alpha peak frequency. The present study specifically investigated this relationship. Digit span was used as the index of WM function. The study made use of 550 normal subjects aged between 11 and 70 years in the Brain Resource International Database. The data were acquired from six laboratories located in the USA (2), Europe (2) and Australia (2). Forward and reverse digit span were found to be lower in older relative to younger age groups. Spontaneous alpha peak frequency slowed with age and more so at anterior than posterior sites. Frontal alpha peak frequency was found to be a significant predictor of reverse digit span, with each 1 Hz increase in frequency associated with a 0.21 increase in reverse digit span score and this was independent of age, indicating a positive relationship between alpha peak frequency and working memory performance.     

Functional differences between human cutaneous mast cells and basophils: a comparison of morphine-induced histamine release

Intravenous administration of morphine sulfate often produces urticarial and hypotensive reactions associated with elevations in plasma histamine. The source of this histamine and mechanisms controlling its release are poorly understood. Previous studies of morphine-induced histamine release compared human leukocytes to rat peritoneal mast cells. The effects of morphine on human cutaneous mast cells has not been examined. We studiedin vitro histamine release from human basophils and human skin preparations containing cutaneous mast cells to evaluate their relative, contribution to the pharmacologic effects of morphine.Human skin mast cell preparations showed dosedependent histamine release over a morphine concentration range of 1.5×10^–5 to 4.5×10^–3 M, with peak release occurring at 5×10^–4 M, with peak release occurring at 5×10^–4 M. Clinically, morphine sulfate is usually injected as a 1.5×10^–2 M solution. Histamine release was calcium dependent and equivalent to that obtained with 3 and 10 mM strontium. Morphologic examination revealed degranulation and exocytosis occurring in morphine-stimulated tissue but not in specimens exposed to buffer alone. Lactate dehydrogenase levels did not increase following morphine incubation, thus supporting a noncytolytic mechanism of histamine release.Basophils, in contrast, showed no significant histamine release from exposure to morphine up to 10^–2 M. Concanavalin A, as a positive control in these same preparations, produced a mean histamine release of 21.0%.Our studies indicate distinct functional differences between human skin mast cell and human blood basophil responses to morphine sulfate. We conclude that the cutaneous and systemic reactions to morphine sulfate probably result from the release of histamine from mast cells rather than from basophils.This study was supported by: National Institutes of Health Grants 2-T32 AMO7153, 5-RO1 AI18615, AI 15557, HL 25831, American Society of Anesthesiologists Starter Grant 1283, and a grant from the Bramble Foundation.     

Quantitative structure-activity relationships and mixture toxicity of organic chemicals in Photobacterium phosphoreum: the Microtox test

Quantitative structure-activity relationships were calculated for the inhibition of bioluminescence of Photobacterium phosphoreum by 22 nonreactive organic chemicals. The inhibition was measured using the Microtox test and correlated with the partition coefficient between n-octanol and water (Poct), molar refractivity (MR), and molar volume (MW/d). At log Poct less than 1 and greater than 3, deviations from linearity were observed. Introduction of MR and MW/d improved the quality of the relationships. The influences of MR or MW/d may be related with an interaction of the tested chemicals to the enzyme system which produces the light emission. The sensitivity of the Microtox test to the 22 tested compounds is comparable to a 14-day acute mortality test with guppies for chemicals with log Poct less than 4. The inhibition of bioluminescence by a mixture of the tested compounds was slightly less than was expected in case of concentration addition. The Microtox test can give a good estimate of the total aspecific "minimum toxicity" of polluted waters. When rather lipophilic compounds or pollutants with more specific modes of action are present, this test will underestimate the toxicity to other aquatic life.     

The Influence of Drugs on Nasal Ciliary Movement

Drugs in nasal preparations, for local use as well as for systemic use, should not interfere with the self-cleaning capacity of the nose, effectuated by the ciliary epithelium. Many drugs and additives, however, have a negative effect on nasal ciliary function. Examples of ciliotoxic agents are lipophilic and mercuric preservatives, local anesthetics, antihistamines, propranolol, and absorption enhancers such as the bile salts. Cholinergic drugs and -adrenergic drugs exert a ciliostimulatory effect. It is the purpose of this review to summarize the present knowledge of ciliotoxicity of drugs and additives and to give recommendations for the use of ciliofriendly drugs in nasal preparations.     

Lymphatic metastasis from tumors transplanted into the pre-irradiated footpad of the rat

Background

In the literature there is some evidence that the incidence of metastases may increase after radiation treatment.

Methods

In order to investigate whether radiation-induced changes in the lymphatic drainage may alter the rate of lymph node metastasis, the center part of the left hind foot of rats was irradiated with a dose of 1 x 55 Gy before inoculation of tumor cells into the irradiated part of the footpad at different time intervals. Cells of 2 different tumor lines were employed. A rarely metastasising rhabdomyosarcoma, R-l, to look for a possible enhancement of lymphatic metastases, and a readily metastasising mammary carcinoma, Cl-2, in case of a possible decrease in the rate of lymphatic metastasis from tumors growing in pre-irradiated footpads.

Results

The incidence of regional lymph node metastasis decreased for R-l tumors growing in pre-irradiated footpads, but not for Cl-2 tumors. Furthermore, the average time required for lymph node metastasis to attain a reference volume of 100 mm³ is not significantly influenced by pre-irradiation of the footpad. No difference was observed in average times for doubling in volume of lymph node metastases originating from primary tumors in pre-irradiated footpads. Abscopal effects after footpad irradiation may cause a 50-fold increase in size of regional lymph nodes and, therefore, histological examination is essential for verification of lymph node metastases.

Conclusions

Damage to the lymphatic system to be expected in the irradiated footpad did not enhance the incidence of regional metastasis of R-1 tumors. A reduced rate of lymphatic metastasis contradicts earlier findings of enhanced lymphatic metastasis development of R-l tumors, growing in pre-irradiated gastrocnemius muscles. The influence of irradiation on regional metastasis formation seems to be “tumor bed” dependent for R-l tumors.     

Value-based design for the elderly: An application in the field of mobility aids

In the aging society, the need for the elderly to remain mobile and independent is higher than ever. However, many aids supporting mobility often fail to target real needs and lack acceptance. The aim of this study is to demonstrate how value-based design can contribute to the design of mobility aids that address real needs and thus, lead to high acceptance. We elicited values, facilitators, and barriers of mobility of older adults via ten in-depth interviews. Next, we held co-creation sessions, resulting in several designs of innovative mobility aids, which were evaluated for acceptance via nine in-depth interviews. The interviews resulted in a myriad of key values, such as “independence from family” and “doing their own groceries.” Design sessions resulted in three designs for a wheeled walker. Their acceptance was rather low. Current mobility device users were more eager to accept the designs than non-users. The value-based approach offers designers a close look into the lives of the elderly, thereby opening up a wide range of innovation possibilities that better fit their actual needs. Product service systems seem to be a promising focus for targeting human needs in mobility device design.     

Complete recovery in plasma of enzymes lost from the heart after permanent coronary artery occlusion in the dog

Plasma activities of creatine kinase (CK) and alpha-hydroxybutyrate dehydrogenase (HBD) were measured after permanent coronary artery occlusion in the dog. Cumulative release of enzymes in plasma was calculated from these data by using a previously validated two-compartment model for circulating enzymes. Regional myocardial ischemia was measured by injection of radiolabeled microspheres. After 48 hours, the dogs were killed, and a detailed map of left ventricular enzyme activity was obtained from 108 tissue samples. Cumulative release into plasma of CK and HBD was 96 +/- 20% and 112 +/- 26%, respectively, of the total activities depleted from the heart (mean +/- SD, n = 11). The scatter in these values is inherent to the calculations, and it is concluded that both enzymes are recovered completely in plasma and, thus, can be used as quantitative markers of injury. Discrepancies between this result and earlier reports on the recovery of CK are only partly apparent and can be explained partly by underestimation of the elimination rate of CK from plasma, irregardless of tissue edema and incomplete extraction of enzyme activity from tissue.