Measurement of acceleration: a new method of monitoring neuromuscular function

A new method for monitoring neuromuscular function based on measurement of acceleration is presented. The rationale behind the method is Newton's second law, stating that the acceleration is directly proportional to the force. For measurement of acceleration, a piezo-electric ceramic wafer was used. When this piezo electrode was fixed to the thumb, an electrical signal proportional to the acceleration was produced whenever the thumb moved in response to nerve stimulation. The electrical signal was registered and analysed in a Myograph 2000 neuromuscular transmission monitor. In 35 patients anaesthetized with halothane, train-of-four ratios measured with the accelerometer (ACT-TOF) were compared with simultaneous mechanical train-of-four ratios (FDT-TOF). Control ACT-TOF ratios were significantly higher than control FDT-TOF ratios: 116 +/- 12 and 98 +/- 4 (mean +/- s.d.), respectively. In five patients not given any relaxant during the anaesthetic procedure (20-60 min), both responses were remarkably constant. In 30 patients given vecuronium, a close linear relationship was found during recovery between ACT-TOF and FDT-TOF ratios. It is concluded that the method fulfils the basic requirements for a simple and reliable clinical monitoring tool.     

Development of resistance to zidovudine in HIV strains isolated from CD4+ lymphocytes and plasma during therapy.

An assay based on production of HIV antigen in cultures of CD4+ lymphocytes infected 'in vitro' with cell-free virus was established. Using this assay it was possible to isolate, propagate and reliably determine the zidovudine susceptibility of HIV isolates from all patients despite differences in cellular tropism and syncytium inducing capacity. Using this assay, differences in zidovudine susceptibility of 52 serial isolates obtained from 16 patients before and after initiation of therapy were examined. HIV with a 10- to 100-fold reduced susceptibility to zidovudine were isolated from 13 patients as early as 4 months after initiation of therapy. Number of months of zidovudine treatment was strongly associated with development of viral resistance, and high CD4 cell counts tended to be associated with lower rates of development of resistance. That patients can harbor mixtures of virus strains with different susceptibility to zidovudine was confirmed by the differences in susceptibility between isolates obtained simultaneously from CD4+ lymphocyte and plasma, and by the differences in susceptibility between virus strains isolated from clones of CD4+ lymphocytes.     

Reversal of postmenopausal vertebral bone loss by oestrogen and progestogen: a double blind placebo controlled study

Because of uncertainty about the place of hormones in the treatment of postmenopausal bone loss vertebral and forearm bone loss was measured by absorptiometry in early postmenopausal women before and after continuous or sequential treatment with combined oestrogen and progestogen in a double blind placebo controlled trial. Treatment with hormones significantly reversed the vertebral bone loss. The net gain in vertebral bone density amounted to 6.4% a year with continuous supplementation and 5.4% a year with sequential supplementation; the net gain in forearm bone density was lower (3.6% with continuous and 3.7% with sequential supplementation). Before a policy of supplementation with hormones can be recommended to all postmenopausal women with the aim of reducing the incidence of vertebral crush fractures further studies with different doses and combinations of hormones, administered over several years, are needed.     

Absorption of chemicals through compromised skin

Skin is an important route of entry for many chemicals in the work place. To assess systemic uptake of a chemical in contact with the skin, quantitative information on dermal absorption rates of chemicals is needed. Absorption rates are mainly obtained from studies performed with intact, healthy skin. At the work place, however, a compromised skin barrier, although not necessarily visible is common, e.g. due to physical and chemical damage. As reviewed in this article, there are several lines of evidence that reduced integrity of the skin barrier may increase dermal absorption of chemicals in the occupational setting. An impaired skin barrier might lead not only to enhanced absorption of a specific chemical, but also to entrance of larger molecules such as proteins and nanoparticles which normally are not able to penetrate intact skin. In addition to environmental influences, there is increasing evidence that some individuals have an intrinsically affected skin barrier which will facilitate entrance of chemicals into and through the skin making these persons more susceptible for local as well for systemic toxicity. This review addresses mechanisms of barrier alteration caused by the most common skin-damaging factors in the occupational settings and the consequences for dermal absorption of chemicals. Furthermore, this review emphasizes the importance of maintained barrier properties of the skin.     

Design and implementation of a telemedicine system using Bluetooth protocol and GSM/GPRS network, for real time remote patient monitoring.

This paper introduces the design and implementation of a generic wireless and Real-time Multi-purpose Health Care Telemedicine system applying Bluetooth protocol, Global System for Mobile Communications (GSM) and General Packet Radio Service (GPRS). The paper explores the factors that should be considered when evaluating different technologies for application in telemedicine system. The design and implementation of an embedded wireless communication platform utilising Bluetooth protocol is described, and the implementation problems and limitations are investigated. The system is tested and its telecommunication general aspects are verified. The results showed that the system has (97.9 +/- 1.3)% Up-time, 2.5 x 10(-5) Bit Error Rate, 1% Dropped Call Rate, 97.4% Call Success Rate, 5 second transmission delay in average, (3.42 +/- 0.11) kbps throughput, and the system may have application in electrocardiography.     

Thrombelastographic measures of clot propagation: a comparison of alpha with the maximum rate of thrombus generation.

The alpha angle alpha (degrees) is a thrombelastographic measure of clot propagation. A parametric measurement of clot propagation [maximum rate of thrombus generation (MRTG), dynes/cm2 per s], however, has recently been utilized. Thus, the relationship of changes in alpha with changes in MRTG were determined. alpha and MRTG values obtained from 859 thrombelastograms was collected from nine studies. Data were analyzed and the relationship between alpha and MRTG defined with commercially available software. Additional comparisons were made retrospectively from whole-blood and plasma data obtained from 33 normal individuals. Data from the nine studies demonstrated that MRTG increased in an exponential fashion compared with increases in alpha (R2 = 0.88, P < 0.001). Whole-blood alpha values were in the range 66.7-74.7 whereas MRTG values were 5.5-10.8, and plasma alpha values were 65.1-77.9 with corresponding MRTG values of 3.5-12.0. Assessment of clot propagation utilizing MRTG provides a more parametric evaluation than the determination of alpha. While normal alpha values may vary by only 12-20%, MRTG values vary by approximately 200-300%. The MRTG should be progressively utilized to a greater extent in both laboratory and clinical settings to parametrically quantify clot growth kinetics with thrombelastography.     

Electromyography of the internal anal sphincter performed under endosonographic guidance description of a new method

PURPOSE: The aim of our study was to investigate internal anal sphincter electromyographic signals. METHODS: Electromyography of the internal anal sphincter was performed with platinum wire electrodes in six healthy volunteers (three males and three females), inserted under endosonographic guidance. Platinum wire electrodes were also inserted into the external anal sphincter. Activity of both the internal and external anal sphincter in a 40-second period was measured. RESULTS: Internal anal sphincter median activity was 22.1 (range, 5.5–67.6) μ V. Slow-wave activity was 47 cycles/minute (range, 34–55 cycles/minute). After inflation of a rectal balloon with air until a constant relaxation of the anal canal was obtained, a decrease in internal anal sphincter activity to 15.9 (1.2–31.3) μV as well as a decrease in slow-wave activity to 34 cycles/minute (range, 27–40 cycles/minute) was found. The original internal anal sphincter EMG was resumed after deflation of the rectal balloon. External anal sphincter median activity was 31 (range, 0.77–18.6)μV. During inflation of the rectal balloon, a reflex increase in external sphincter EMG activity was found. With the rectal balloon fully inflated a part of this increase was still present, 11.0 (1.9–24.6)μV. In some of the subjects, this increased activity was superimposed on the internal anal sphincter recordings as well. During a voluntary squeeze it was not possible to identify internal anal sphincter activity due to activity of the external anal sphincter totally overriding the internal anal sphincter signal. CONCLUSION: Precise EMG recordings from the internal anal sphincter is possible with endosonographic guidance of the electrodes, except during voluntary squeezing of the external anal sphincter.     

Hormone replacement therapy dissociates fat mass and bone mass, and tends to reduce weight gain in early postmenopausal women: a randomized controlled 5-year clinical trial of the Danish Osteoporosis Prevention Study.

The aim of this study was to study the influence of hormone replacement therapy (HRT) on weight changes, body composition, and bone mass in early postmenopausal women in a partly randomized comprehensive cohort study design. A total of 2016 women ages 45-58 years from 3 months to 2 years past last menstrual bleeding were included. One thousand were randomly assigned to HRT or no HRT in an open trial, whereas the others were allocated according to their preferences. All were followed for 5 years for body weight, bone mass, and body composition measurements. Body weight increased less over the 5 years in women randomized to HRT (1.94 +/- 4.86 kg) than in women randomized to no HRT (2.57 +/- 4.63, p = 0.046). A similar pattern was seen in the group receiving HRT or not by their own choice. The smaller weight gain in women on HRT was almost entirely caused by a lesser gain in fat. The main determinant of the weight gain was a decline in physical fitness. Women opting for HRT had a significantly lower body weight at inclusion than the other participants, but the results in the self-selected part of the study followed the pattern found in the randomized part. The change in fat mass was the strongest predictor of bone changes in untreated women, whereas the change in lean body mass was the strongest predictor when HRT was given. Body weight increases after the menopause. The gain in weight is related to a decrease in working capacity. HRT is associated with a smaller increase in fat mass after menopause. Fat gain protects against bone loss in untreated women but not in HRT-treated women. The data suggest that women's attitudes to HRT are more positive if they have low body weight, but there is no evidence that the conclusions in this study are skewed by selection bias.     

Persistence of systemic mastocytosis after allogeneic bone marrow transplantation in spite of complete remission of the associated myelodysplastic syndrome.

A myelodysplastic syndrome (MDS), type 5 (RAEB-t), and systemic mastocytosis affecting the spleen, the splenic lymph nodes, the bone marrow and the liver were diagnosed in a 38-year-old woman. The clinical course was complicated by splenic vein thromboses and iliac artery embolism. The thrombotic episodes might be secondary to mast cell mediator release. A complete remission of the MDS was obtained by allogeneic bone marrow transplantation, but the mastocytosis persisted. Thus, the possibility that the mast cell originates from a common myeloid precursor cell may be questioned.