Does Standing Affect Acetabular Component Inclination and Version After THA?

Background  

Avoiding complications after hip arthroplasty with hard-on-hard bearings, especially metal-on-metal, correlates with the position of the acetabular component. Supine imaging with conventional radiography has traditionally been utilized to assess component inclination (abduction), as well as anteversion, after THA and surface replacement arthroplasty (SRA). However, most adverse events with hard bearings (excessive wear and squeaking) have occurred with loading. Standing imaging, therefore, should provide more appropriate measurements.     

Consequences of magnocellular dysfunction on processing attended information in schizophrenia

Schizophrenia is associated with perceptual and cognitive dysfunction including impairments in visual attention. These impairments may be related to deficits in early stages of sensory/perceptual processing, particularly within the magnocellular/dorsal visual pathway. In the present study, subjects viewed high and low spatial frequency (SF) gratings designed to test functioning of the parvocellular/magnocellular pathways, respectively. Schizophrenia patients and healthy controls attended to either the low SF (magnocellularly biased) or high SF (parvocellularly biased) gratings. Functional magnetic resonance imaging (fMRI) and recordings of event-related potentials (ERPs) were carried out during task performance. Patients were impaired at detecting low-frequency targets. ERP amplitudes to low-frequency gratings were diminished, both for the early sensory-evoked components and for the attend minus unattend difference component (the selection negativity), which is regarded as a neural index of feature-selective attention. Similarly, fMRI revealed that activity in extrastriate visual cortex was reduced in patients during attention to low, but not high, SF. In contrast, activity in frontal and parietal areas, previously implicated in the control of attention, did not differ between patients and controls. These findings suggest that impaired sensory processing of magnocellularly biased stimuli lead to impairments in the effective processing of attended stimuli, even when the attention control systems themselves are intact.     

The Role of Preload Forces in Spinal Manipulation: Experimental Investigation of Kinematic and Electromyographic Responses in Healthy Adults

Objectives

Previous studies have identified preload forces and an important feature of skillful execution of spinal manipulative therapy (SMT) as performed by manual therapists (eg, doctors of chiropractic and osteopathy). It has been suggested that applying a gradual force before the thrust increases the spinal unit stiffness, minimizing displacement during the thrust. Therefore, the main objective of this study was to assess the vertebral unit biomechanical and neuromuscular responses to a graded increase of preload forces.

Methods

Twenty-three participants underwent 4 different SMT force-time profiles delivered by a servo-controlled linear actuator motor and varying in their preload forces, respectively, set to 5, 50, 95, and 140 N in 1 experimental session. Kinematic markers were place on T6, T7, and T8 and electromyographic electrodes were applied over paraspinal muscles on both sides of the spine.

Results

Increasing preload forces led to an increase in neuromuscular responses of thoracic paraspinal muscles and vertebral segmental displacements during the preload phase of SMT. Increasing the preload force also yielded a significant decrease in sagittal vertebral displacement and paraspinal muscle activity during and immediately after the thrust phase of spinal manipulation. Changes observed during the SMT thrust phase could be explained by the proportional increase in preload force or the related changes in rate of force application. Although only healthy participants were tested in this study, preload forces may be an important parameter underlying SMT mechanism of action. Future studies should investigate the clinical implications of varying SMT dosages.

Conclusion

The present results suggest that neuromuscular and biomechanical responses to SMT may be modulated by preload through changes in the rate of force application. Overall, the present results suggest that preload and rate of force application may be important parameters underlying SMT mechanism of action.     

ACR Appropriateness Criteria® Pretreatment Planning of Invasive Cancer of the Cervix

The prognosis of cervical cancer is linked to lymph node involvement, and this is predicted clinically and pathologically by the stage of the disease, as well as the volume and grade of the tumor. Staging of cervical cancer based on International Federation of Gynecology and Obstetrics (FIGO) staging uses physical examination, cystoscopy, proctoscopy, intravenous urography, and barium enema. It does not include CT or MRI. Evaluation of the parametrium is limited in FIGO staging, and lymph node metastasis, an important prognostic factor, is not included in FIGO staging. The most important role for imaging is to distinguish stages Ia, Ib, and IIa disease treated with surgery from advanced disease treated with radiation therapy with or without chemotherapy. This article reviews the current role of imaging in pretreatment planning of invasive cervical cancer. The ACR Appropriateness Criteria(?) are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.     

骨髓干细胞动员治疗脑缺血损伤

学术背景：近来的研究表明，来源于骨髓的干细胞具有横向分化潜能和成神经分化特性，对脑缺血损伤后神经功能恢复和神经细胞的修复具有保护作用。 目的：通过回顾近年来骨髓干细胞动员对脑缺血损伤保护作用的文献，对骨髓干细胞的特性及动员过程、途经,可能的作用机制、影响因素进行阐述，以期完善骨髓干细胞动员防治脑缺血损伤的基础与临床研究。 检索策略：应用计算机检索Medline1997—01／2007—01与骨髓干细胞动员和脑缺血相关的文章。检索词“bone marrow stem cells，cerebral ischemia”并限定语言种类为English，同时计算机检索CNKI数据库1997—01／2007—01相关文章，并限定文章语言种类为中文，检索词为“骨髓干细胞，脑缺血”。就检索到的300余篇文献进行筛选，选择以骨髓干细胞动员和脑缺血损伤的基础研究为主要内容的文献63篇，其中研究内容相似的，以近5年且发表在较权威杂志者优先。 文献评价：将入选的30篇文献进行分类，11篇研究骨髓干细胞的生物学特性，19篇与骨髓干细胞动员治疗脑缺血损伤的过程．途经,可能的作用机制、影响因素相关。 资料综合：来源于骨髓的干细胞具有很强的“可塑性”，自我更新和高度增殖能力，其可能通过修复和替代脑缺血损伤后的神经细胞，促进或直接参与缺血区新生血管生成，分泌神经营养因子等，对脑缺血损伤后神经功能恢复发挥保护作用，其作用机制和作用方式目前尚不确切，有待于建立完整的动物模型技术平台，通过基础研究进行解决。 结论：骨髓干细胞对脑缺血损伤具有修复作用，采用骨髓干细胞动员的干预策略，方法简便、安全有效,无创伤且可避免干细胞移植的免疫排斥反应，具有较好的发展潜力，有望成为治疗脑缺血性疾病的研究重点。     

A comparative trial of granulocyte-colony-stimulating factor and dexamethasone, separately and in combination, for the mobilization of neutrophils in the peripheral blood of normal volunteers

BACKGROUND: The clinical utility of polymorphonuclear neutrophil (PMN) transfusion therapy has been compromised, in part, by the inability to obtain sufficient quantities of functional neutrophils from donors. To define the optimal conditions for mobilization of PMNs in granulocyte donors, the effects of granulocyte-colony-stimulating factor (G-CSF) and dexamethasone, separately and in combination, on PMN counts in normal volunteers were compared. STUDY DESIGN AND METHODS: Five normal subjects were randomly assigned to each of the following single-dose regimens in 5 consecutive weeks: 1) G-CSF, 300 micrograms given subcutaneously; 2) G-CSF, 600 micrograms subcutaneously: 3) dexamethasone, 8 mg given orally; 4) G-CSF, 300 micrograms subcutaneously, plus dexamethasone, 8 mg orally; and 5) G-CSF, 600 micrograms subcutaneously, plus dexamethasone 8 mg orally. Venous blood was collected at 0, 6, 12, and 24 hours after drug administration for the determination of absolute neutrophil counts (ANCs). RESULTS: Maximal ANC was achieved at 12 hours after each regimen, except dexamethasone alone (maximum, 24 hours). Dexamethasone significantly increased the maximal ANC induced by either dose of G-CSF alone (p < 0.05). The greatest mobilization of PMNs occurred after the administration of G-CSF (600 micrograms) and dexamethasone (8 mg); the ANC increased from a mean baseline value of 3,594 per microL to 43,017 per microL at 12 hours. All of the drug regimens were well tolerated. CONCLUSION: Dexamethasone significantly increases the level of neutrophilia induced in normal subjects by G-CSF. The combination of dexamethasone and G-CSF (at the dosages used in this study) is a convenient, well-tolerated regimen for the mobilization of PMNs in the peripheral blood of granulocyte donors. Moreover, the optimal quantitative yield of PMNs is likely to be achieved by leukapheresis 12 hours after drug administration.     

A model to determine required pool size for HLA-typed community donor apheresis programs

Community donor plateletpheresis programs must have adequate numbers of HLA-typed donors to support the transfusion needs of alloimmunized patients, and donor pool size calculations should reflect the fact that each patient needs more than one donor to provide his or her support. The average number of donors needed to provide a patient's support was estimated as a function of donor usage and commitment. A model was developed for determining an appropriate size of the donor pool for a community donor plateletpheresis program that would incorporate the average number of donors needed per patient, the level of HLA compatibility to be maintained between patient and donor, and the frequencies of patient and donor HLA phenotypes. A database of 4338 plateletpheresis transfusions given to 591 patients from a pool of up to 870 community donors over a 3-year period was analyzed retrospectively to validate the estimates of the average number of donors needed to support a patient, which ranged from 4 to 33 donors. This database was also used to illustrate the application of the pool size determination model. Model results suggest that plateletpheresis donor pools of 1000 to 3000 donors are capable of meeting the transfusion needs of most patients at an HLA-match grade of B2 or better.     

EFFECT OF SUBCLINICAL LEAD INTOXICATION ON LARYNGEAL CANCER

SUMMARY In this study we investigated the possible relationship of laryngeal cancer and subclinical lead intoxication, using the depression of aminolevulinic acid dehydratase (ALAD) activity in blood as indicator. Twenty-six patients with laryngeal cancer and 53 normal controls met the criteria to enter the study. Blood ALAD activity values in the patients with laryngeal cancer ranged from 27.1 to 75.3 U/l with a mean of 50.79 U/l. The respective values in the control group ranged from 36.2 to 98 U/l with a mean of 59.76 U/l. There was a statistically significant difference between the two means (0.001 <p<0.01), whereas blood lead concentrations in all patients were within normal limits. These findings support the hypothesis that low level lead intoxication (subclinical blood lead levels), from cars, industries and products, may contribute to the risk of laryngeal cancer. Further investigation is needed to clarify the exact relationship between lead and cancer of the larynx.