Combined use of a true-bipolar sensing implantable cardioverter defibrillator in a patient having a prior implantable spinal cord stimulator for intractable pain

Reported is a case involving a patient with a previously implanted spinal cord stimulator (SCS) who presented for an implantable cardioverter defibrillator (ICD). The SCS device was located in the left lower abdominal quadrant with a stimulation electrode array placed on the dorsal aspect of the spinal cord at the T-11 thoracic level. Interaction testing demonstrated that the biopolar sensing transvenous ICD system (Medtronic 7221 Cx PCD) did not detect the stimulator's output at burst rates ranging from 20-130 pulses/s, even with the ICD set to its maximum sensitivity of 0.15 m V and the stimulator programmed to the highest patient tolerated output combinations of 5 V, 0.45 ms in the bipolar configuration and 3 V, 0.45 ms in the unipolar (i.e., case-electrode) configuration.     

Hemodynamic response to in situ latissimus dorsi muscle stimulation: implications in dynamic cardiomyoplasty

Dynamic cardiomyoplasty (DCM) involves the electrical stimulation of a pedicled latissimus dorsi muscle flap wrapped around the falling ventricle as a means of cardiac assist. To further elucidate a potential neurohumoral mechanism for improvement of cardiac output after myoplasty, we evaluated the hemodynamic effects of in situ stimulation of the latissimus dorsi muscle (in the absence of cardiomyoplasty). In seven mongrel dogs, a nerve cuff electrode (Medtronic 6901) was placed around the left thoracodorsal nerve (TDN). This was attached to a pulse generator (Medtronic, Itrel 7420), delivering a 4.0 volt, 0.19 second on, 0.81 second off, 33 Hz, 210 microsecond pulse width, cyclic bursts similar to that used in DCM. Stroke volume index (SVI) and other hemodynamic parameters as well as plasma norepinephrine (NE) levels were measured at five stages: baseline, stimulator on at 0, 2, and 5 minutes, and stimulator off at 30 minutes after. The animals were then subjected to 4 weeks of rapid pacing at 240 beats/min (Medtronic 8329) to induce heart failure, and as the rapid pacing was discontinued, measurements were repeated as above. After rapid pacing, cardiac function was significantly depressed, and NE was elevated (133 +/- 69 versus 500 +/- 353 pg/mL, p < 0.05). In the normal hearts, TDN stimulation increased SVI, heart rate, systemic pressure, and NE levels. In heart failure, however, no significant changes in cardiac function and NE levels were noted. In conclusion, our data indicate that in the normal hearts, afferent impulses from TDN stimulation alone may augment cardiac function by means of a neurohumoral effect that is not seen in severe heart failure. The implications of these findings in DCM are discussed.     

Long-term biocompatibility of a miniature stimulator implanted in feline hind limb muscles

Chronic foreign-body responses and muscular changes were examined following the implantation of active miniature stimulators into the hind limb muscles of cats for periods of up to three months. The radio-frequency (RF)-powered stimulators were injected into muscles through a 12-gauge hypodermic needle. The tissue responses around the active stimulators were compared histologically to those provoked by passive devices, broken glass, silicone tubing, polyester suture material coated with polybutylate, and two of the internal components of the stimulator (ferrite, integrated circuit chip). Active and passive stimulators produced similar, benign foreign-body reactions that resulted in an essentially identical fibrous capsule over time. The responses were similar to those produced by the internal components and the suture material, and were more modest than those produced by the broken glass. The capsule did not appear to interfere with the functionality of active devices because thresholds measured during the post-implantation survival period did not change significantly over time. Unexpectedly, the severity of the reaction differed significantly amongst the various target muscles. Medial gastrocnemius exhibited the most severe response, whereas tibialis anterior had the least reaction.     

铝带冷轧机控制程序的模块化设计

文章分析了高速轧机系统的具体需求,介绍了一种通过模块化程序设计来实现高速轧机控制系统的方法,并阐述了在西门子STEP7和WinCC集成控制平台上实现这种设计的具体步骤。实践证明,该设计方法可以满足现代化高速轧机的控制要求,并为其他大型控制系统的设计提供参考和借鉴。     

The U.S. home infusion market

Medicare legislation stimulated the development of home care services but also resulted in fragmentation of service components. In the 1980s, prospective pricing and diagnosis-related groups, and resulting pressures to reduce inpatient length of stay, prompted additional growth of the industry. Even so, in 1995 home care represented only 3% of total national expenditures on health care. The annual growth rate of the home infusion industry dropped from 64% in 1982-86 to 24% in 1986-93. While revenue per patient for home infusion is expected to decrease under managed care, an increasing number of patients will support continued market growth. The home infusion market is highly competitive, with only a few large national providers and many small local providers. In 1996, 29% of acute care hospitals provided or were developing a home care program. Community pharmacists' options in the home infusion area include independent services, partnerships, joint ventures, contracts with hospitals, and franchises. The home infusion market is being integrated into alternative sites, such as ambulatory infusion centers (AICs), as providers attempt to diversify to maintain managed care contracts. AICs provide infusion therapy and nursing to noninstitutionalized, nonhome-bound patients. Untapped sources for future growth of the infusion market include long-term-care facilities. More consistent studies of the home care market are needed. Despite slowed growth in recent years, home care has a strong market in the United States.     

The U.S. pediatric cancer clinical trials programmes: international implications and the way forward

The four national paediatric cancer clinical trials organisations in the United States--the Children's Cancer Group, the National Wilms' Tumor Study Group, the Intergroup Rhabdomyosarcoma Study Group and the Pediatric Oncology Group--were formed in 1955, 1969, 1972 and 1979, respectively. Together, the Children's Cancer Group and Pediatric Oncology Group serve as a national registry of nearly all childhood cancers in the United States, provide a national network of communication for researchers, care providers and families of paediatric patients with malignant disease and conduct laboratory investigations and clinical trials of new treatments of cancers in infants, children, adolescents and young adults. Nearly 95% of patients with cancer in the United States who are below 15 years of age are registered by the Children's Cancer Group and the Pediatric Oncology Group and more than half of American children with cancer are entered into at least one trial by a paediatric group. Improved survival of children receiving treatment according to well-defined protocols in specialised children's centres, in contrast to children who received treatment outside of these centres, has been shown for those with acute lymphoblastic leukaemia, lymphoma, Wilms' tumour, medulloblastoma, rhabdomyosarcoma and Ewing's sarcoma. By the year 2000, the overall cure rate for United States children and adolescents with cancer should exceed 85%. To reach this goal, the way forward will depend on international collaboration, implementation of global harmonisation, prevention of the erosion of biomedical research and clinical trials by the managed health care industry, increased public and private financial support and continued recruitment into paediatric oncology of brilliant and dedicated young investigators. The specific challenges ahead include: (1) transferring the knowledge, methodologies and technologies to countries that are less fortunate; (2) conducting multinational clinical trials in conjunction with paediatric cooperative groups in other countries; (3) accessing older adolescent patients who currently do not participate in cooperative group trials; (4) merging clinical trials by adult collaborative groups that overlap with the paediatric groups, as in acute lymphoblastic leukaemia, acute myelogenous leukaemia, Hodgkin's disease, osteosarcoma and germ cell tumours; (5) establishing a stable source of funding for national and international cooperative paediatric cancer clinical trials; (6) creating an informatics system that can link paediatric cooperative group operation centres around the world, and the institutions within each collaborative group; and (7) securing the support of the insurance industry and government in covering clinical trials.     

多功能喷射混凝土机器人控制系统研究

针对喷射混凝土机器人存在的问题,对产品的机械结构和控制系统进行模块化重新划分、构造,基本实现了喷射混凝土机器人的多功能化。本文介绍了无线遥控控制系统的设计与实现,包括输入信号采集电路板、无线发送模块、无线接收模块以及输出控制电路板。     

Comparison of U.S. Project Delivery Systems

Construction management at risk, design∕build and design∕bid∕build are three principal project delivery systems used in the United States today. This paper empirically compares cost, schedule, and quality performance of these three project delivery systems, using project-specific data collected from 351 U.S. building projects. The study included collecting, checking, and validating industry data, significance testing of univariate comparisons and the statistical development of multivariate linear regression models for predicting average project performance. A nonresponse study verified statistically that collected data were appropriate for analysis and representative of the industry from which they were drawn. Significance testing and multivariate comparisons used nearly 100 explanatory and interacting variables to explain project cost, schedule, and quality performance. Specific comparisons between project delivery systems, performance metrics, and six facility classes are discussed. Results and the level of confidence that surrounds each finding are presented.     

Thoracoscopic sympathectomy: the U.S. experience

OBJECTIVE: 48 patients underwent TSSYM. Charts of patients undergoing thoracoscopy were reviewed to assess the safety and efficacy of thoracoscopic sympathectomy (TSSYM). DESIGN: A retrospective review was undertaken at four United States medical centers. RESULTS: TSSYM was performed for reflex sympathetic dystrophy in 27 patients, hyperhydrosis palmaris in 15 patients, and Raynaud's upper extremity ischemia and splanchnic pain in 2 patients each. Anesthesia with one lung ventilation was used. 2.9 ports were used per patient and 0.8 chest tubes were placed per patient. All patients underwent resection of the sympathetic chain, usually with a clip along the bottom of the resected chain. Laser, electro-ablation and electroresection were not used by any of the surgeons in his series. The mean length of hospital stay was 1.8 days. CONCLUSIONS: TSSYM is a safe and effective technique for treatment of a variety of thoracic disorders.     

Visual attention and the perception of features and objects.

Feature integration theory (Treisman & Gelade, 1980) suggested that simple features are coded in parallel in a number of specialized feature maps, but that focussed attention is required to ensure the correct integration of features to specify objects. This is done by a serial scan through a master-map of locations, giving access to the features currently occupying the attended location. These are then integrated to form a representation of the object in the selected location. The present paper reviewed new evidence that has accrued since 1980 and elaborated the model to accommodate the recent findings. The proposal is that four different mechanisms may be involved in different conditions: selection of locations, directed by an externally controlled window of attention; selection by features through preattentive grouping; selection of objects; and selection for access to responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development and Application of the Specialist Task Organization Procurement Approach

The study focuses on the development of an innovative procurement method in order to improve owners’ contracting strategies. The aim of this paper is to develop a procurement system that improves the overall project implementation process, in order to meet the project objectives of time, cost, and quality. The Specialist Task Organization (STO) approach is suggested based on a constructive research approach, where extensive theoretical development of the STO concept is developed. The analogical validation was carried out through the review of four case study examples in order to find the analogies between the positive outcomes of four case studies and the elements of the STO route. The proposed task-oriented approach utilizes integrated product (task) development, integrated management, and fragmented execution via task organizations. The merits of the STO approach include, the shifting of competition from only single design and cost based to multiple designs, life-cycle costs, alternative materials, and maintainability implications. The STO approach assumes a modular approach to design, and allows experts knowledge in design and construction through their involvement from preconstruction through project starts up. The suggested STO route is a potential tool in realizing complete sustainability in construction in terms of environmental and social sustainability, as well as economic sustainability.     

Reflex electrical stimulation for urinary incontinence

Our previous observations have shown that the electrical stimulation of muscles is prevalently reflex. One of the advantages of reflex stimulation is that it activates not only a limited number of motor units, but rather a number of muscles connected by the same reflex from a single stimulation site. Consequently, it is not necessary to place electrodes into the muscle to be activated. They can be put elsewhere provided that the same effect is obtained and that it is more convenient for the patient. Such an opportunity arises when treating urinary incontinence which involves not only the urethral sphincter but also the group of synergistic muscles of the pelvic floor. Our experiments with several patients suffering stress incontinence have shown that indirect stimulation of the levator ani with a vaginal stimulator and especially of the anal sphincter with an anal stimulator affects the urethral sphincter in the same way as direct stimulation. These findings are significant since they enable us to use external instead of implantable stimulators. External stimulation is worth trying in all cases of stress incontinence where conservative measures have failed. In our cases, the results have been very satisfactory.     

Multiple sexual partners among U.S. adolescents and young adults

CONTEXT: Because many teenagers and young adults fail to use condoms correctly and consistently, the number of sexual partners they have is an important risk factor for sexually transmitted diseases, including HIV. Identifying factors that are associated with having multiple partners can help in the design of disease interventions. METHODS: Data on 8,450 males and females aged 14-22 who participated in the 1992 Youth Risk Behavior Survey were used to examine the prevalence of and factors associated with young people's having multiple partners. RESULTS: In all, 63% of female respondents and 64% of males were sexually experienced. Among those who had had sex during the three months before the survey, 15% and 35%, respectively, had had two or more partners during that period. At each age, the majority of sexually experienced respondents had had more than one lifetime partner; between ages 14 and 21, the proportion who had had six or more rose from 8% to 31% among females and from 14% to 45% among males. In logistic regression analyses, alcohol use, illicit drug use and young age at first coitus were associated with increased odds that females had had two or more partners in the previous three months, and being married lowered the odds; black or Hispanic race or ethnicity, alcohol use and young age at first coitus increased the odds for males, and being married reduced the odds. As the number of reported alcohol-related behaviors increased, the adjusted proportion of respondents who had recently had multiple partners rose from 8% to 48% among females and from 23% to 61% among men. CONCLUSIONS: The strong association between alcohol use and having multiple sexual partners underscores the need to educate young people about the effects of alcohol on partner choice and the risk of infection with sexually transmitted diseases.     

Physiological perspectives on leptin as a regulator of reproduction: role in timing puberty

Effects of tumor stimulator cell modification by infection with Newcastle Disease Virus (NDV) are described as analysed in vitro in mixed lymphocyte tumor cell cultures (MLTC). Direct antitumor effects were seen with human melanoma or colon-carcinoma cells in a dose- and time-dependent manner when using live but not UV inactivated virus. When T cell stimulation was measured by [3H]-thymidine uptake, NDV infected tumor stimulator cells did not show an augmentation but rather an inhibitory effect in comparison to non-infected stimulator cells. Virus infected tumor stimulator cells were, however, capable of augmenting the induction of tumor specific cytotoxic T cells in MLTC-CML assays when using murine ESb lymphoma immune cells and syngeneic NDV modified ESb cells as stimulators. A CML stimulatory effect was also shown for NDV modified third party cells and thereof derived conditioned medium. These effects are most likely explained by interferon- which is induced in tumor cells by NDV infection and by interferon-á which is induced in responder cells when stimulated with NDV infected stimulator cells.     

U.S. Construction Labor Productivity Trends, 1970–1998

Construction productivity trends carry immense consequences for the economy as a whole. However, there is little scholarly consensus concerning even the direction of such trends. The main objectives of this paper are to (1) present an approach to studying long-term productivity trends in the U.S. construction industry; and (2) provide a preliminary indication of such trends over the past 25–30 years. Subsequent, extended statistical studies are suggested that may be based on the approach of the selected work presented here. Labor cost and output productivity trends are tracked for tasks that represent different trades and differing levels of technological intensity within the building construction sector. Specific tasks dealt with a range from a zero technology impact task, such as hand trenching, to compaction with a sheepsfoot roller. Means's cost manuals were used to trace the benchmark values for these tasks. These values reflect productivity trends. Unit labor costs in constant dollars and daily output factors were compared over decades for each task. Direct work rate data from 72 projects in Austin, Tex., over the last 25 years were also examined. Increasing the direct work rate usually increases construction productivity. The combined data indicate that productivity has increased in the 1980s and 1990s. Depressed real wages and technological advances appear to be the two biggest reasons for this increase. The data also indicate that management practices were not a leading contributor to construction productivity changes over time. Subsequent studies are required to add weight to these observations and can be based on the approach presented here.     

Anion and osmolal gaps in a patient with alcoholism

Thirty-two patients with failed back syndrome received a trial of spinal cord stimulation. Stimulators were internalized in 26; long-term follow-up was available for 23 of these patients. Seventy-six percent of the 22 patients with stimulators still present at 1 year and 74% of the 19 patients with stimulators still present at 2 years were receiving 50% or better pain relief. Patients routinely underwent pain team evaluation and therapy, psychological testing and a transcutaneous electrical nerve stimulator trial prior to consideration of spinal cord stimulation. The most common complication was electrode migration. Spinal cord stimulation should be considered as an important therapeutic modality in carefully selected patients with failed back syndrome.     

The influence of accreditation on educational change in U.S. medical schools

The authors examined the influence of accreditation on educational change and reform in U.S. medical schools in the past decade, by reviewing the survey databases and site visit reports of 90 schools that had comprehensive accreditation surveys by the Liaison Committee on Medical Education (LCME) between July 1992 and June 1997. In this study, substantive change was defined as centralizing the design and management of the curriculum, as well as one or more of the following reforms: integrating basic and clinical science instruction and/or conversion to interdisciplinary courses; implementing methods of active, small-group, independent, and hypothesis-based learning; and substantially increasing students' exposure to ambulatory and primary care. Accreditation reports were reviewed to determine the extent to which the LCME previously had admonished schools for shortcomings in their educational programs and advised curricular changes. Notice was taken of grant support by national foundations promoting educational reform, in relation both to the correction of accreditation deficiencies and to curricular reform undertaken by schools on their own initiative. The study also scrutinized the evolution of accreditation standards promoting educational reform, and the LCME's support of initiatives for shortening the period of medical education and promoting performance-based teaching and the assessment of clinical skills. On entering the 1990s, the LCME toughened the standards for design and management of the medical curriculum and for the evaluation of educational program effectiveness that schools must conduct. The greater assessment rigor identified educational shortcomings in 61 of 90 medical schools coming up for accreditation surveys during 1992-1997. On those occasions, 34 of the 61 schools had instituted reforms or were on the verge of doing so. Twenty-five of the schools carrying out reforms (73%) had received major foundation grants, compared with ten of the 27 schools (37%) that had accomplished little. Fifteen schools that had not been reproached earlier were found on the 1992-1997 surveys to have undertaken substantial innovation on their own initiative, five with the help of major foundation awards. The study also shows that a number of schools implemented parts of more sweeping reforms with the help of smaller foundation grants for more discrete purposes. In some instances, it has not been possible to differentiate the influence of the LCME as a force for educational reform from the incentives for change created by national foundations. Overall, the LCME, through its standards and assessment practices, and in synergy with schools and kindred agencies promoting change, is now on the leading edge of improved education and evaluation in the nation's medical schools.     

Supervisory and administrative clinical psychologists in U. S. psychiatric hospitals.

An analysis of job titles, salary ranges, education and experience requirements, working hours, etc., of clinical psychology positions requiring supervisory and/or administrative duties. It was concluded that the APA "could assist in standardization of titles and duties, equalization of salaries, and the definition of proper training for such roles." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Banner year for U.S. longevity

Tumor-associated proteins are studied immunohistochemically in 86 medulloblastomas (MB). Three main variants of their coexpression (70% of all cases studied) are distinguished. The 1st variant (24 cases): expression of Rb and nm23 proteins and the lack of tenascin expression. The 2nd variant (25 cases): tenascin expression and lack of Rb and nm23 expression. The 3rd variant (12 cases): the expression of tenascin, Rb, p53 and/or bc12. Tenascin-positive MB much more frequently expressed oncoproteins p53, bc12, c-erb B-2 and p30/32, and had higher indices of "growth fraction". Tenascin immunoreactivity and that of other oncoproteins prevailed in MB with desmoplasia and in tumors with immunohistochemical features of neuronal differentiation.