Langerhans' cell histiocytosis in patients older than 21 years

In this retrospective review of 541 patients with Langerhans' cell histiocytosis, 211 (39%) patients were older than 21 years of age, whereas 330 (61%) were younger than 21 years of age. The adult patients had a mean age of 32 years (range, 21-69 years) with 159 (75%) men and 52 (25%) women, whereas the pediatric patients consisted of 176 (55%) boys and 144 (45%) girls. This male predominance in adults was statistically significant. Three adults had the Hand-Schuller-Christian variant, whereas the remaining adults (208) had eosinophilic granuloma. The rib accounted for 25% of the adult lesions and only 8% of the pediatric lesions. Spine involvement was less common in the adult group (3% versus 10%) and was predominantly thoracic. The adult patients had 40 (77%) diaphyseal lesions, 12 (23%) metaphyseal lesions, and no epiphyseal lesions. The pediatric patients had 75 (54%) diaphyseal, 59 (42%) metaphyseal, and five (4%) epiphyseal lesions. Radiographic evaluation revealed similar margin and matrix patterns in both groups, with a geographic lesion without sclerotic borders being the most common pattern. Langerhans' cell histiocytosis is considered a pediatric disease. However, this study showed a significant number (39%) of patients older than 21 years of age with this condition.     

Postbiopsy renal transplant arteriovenous fistulas: color Doppler US characteristics

Color Doppler ultrasound (US) with point-spectral analysis was performed on eight patients with postbiopsy renal transplant arteriovenous fistulas. Waveform analysis of the supplying artery documented decreased resistive indices in all cases and increased flow velocities in seven. The peak-systolic flow velocity in the arteries supplying the fistulas ranged from 55 to 180 cm/sec (mean, 92 cm/sec), while the range in normal arteries was 20-52 cm/sec (mean, 32 cm/sec). The resistive indices of the arteries supplying the fistulas ranged from 0.31 to 0.50 (mean, 0.45), while the resistive indices of the normal arteries ranged from 0.60 to 0.92 (mean, 0.74). Arterialization of the venous waveform from the draining vein was also documented in all cases. In six cases, the increased flow velocities resulted in increased color saturation toward white in the supplying artery (n = 2) or in both the artery and the draining vein (n = 4), which was detectable on the realtime image. In six cases, flow turbulence resulted in localized tissue vibration, which appeared as random color assignment in extravascular renal parenchyma adjacent to the fistula. Knowledge of these imaging and Doppler characteristics should aid in the identification of renal transplant arteriovenous fistulas with color Doppler US.     

Paget's disease of bone in patients younger than 40 years

Paget's disease of bone, although common in the United States, is relatively rare in patients younger than 40 years. In a large archival series, 10% of patients with Paget's disease of bone were younger than 40 years. Pain followed by pathologic fracture was the most common presenting complaint in this group of patients. There was no gender difference comparing the younger group with the older group of patients. Of the 521 patients in this series, only 10 were African-American; the others were Caucasians. Seven African-American patients were in the group of patients who were younger than 40 years. Appendicular and monostotic bone involvement was more frequent in the younger age group although these differences were not statistically significant. The incidence of malignant transformation in pagetic bone was high (30.3%), and is a reflection of the high volume of uncommon tumor referrals to our consultation service. However, there were no cases of associated malignancies in the group of patients younger than 40 years.     

Stepwise methodology for plain radiographic assessment of pedicle screw placement: a comparison with computed tomography

OBJECTIVE: The objective of this study is to evaluate the effectiveness of a specific methodology for plain radiographic assessment of lumbar pedicle screw position. PURPOSE: To evaluate the effectiveness of using orthogonal plain radiographs and a systematic method of interpretation, developed by the senior author, in assessing the placement of lumbar and lumbosacral pedicle screws. STUDY DESIGN: This was an adult cadaver study of the accuracy of using plain radiographs or computed tomography to assess pedicle screw position. Plain radiographs were performed and compared with computed tomography (CT) scans. Gross anatomic dissections were performed to directly confirm screw position. Variables, including screw material, radiographic view, and screw dimensions, were assessed for their effect on the ability of physicians to determine pedicle screw position. Multiple readers were included in the study, including 1 spine Fellow, 3 experienced orthopedic spine surgeons, and 1 neuroradiologist. METHODS: Five adult cadaveric spines were instrumented with titanium pedicle screws from L1 to S1. Screws were placed outside the confines of the pedicle in all 4 quadrants or within the pedicle using a Latin-Square design. Each cadaver was imaged with orthogonal radiographs and high-resolution CT scans. The spines were then reimaged after the instrumentation was replaced with stainless steel screws placed in the identical position. Finally, each spine was dissected to assess the exact position of the screws. Images were read in a blinded fashion by 1 spine fellow, 2 staff surgeons, and a staff radiologist. The results were compared with the known screw positions at dissection. RESULTS: In total, 120 pedicle screws were placed, 44 (38%) outside the confines of the pedicle. Sensitivity, defined as the percent of the misplaced screws that were correctly identified, was similar across the 3 diagnostic tests, but markedly improved when all CT formats were considered together. Similarly, specificity, defined as the percent of screws correctly read as being placed within the pedicle, was independent of radiographic examination. Sensitivity of the radiographic technique was 70.1% and specificity was 83.0%, whereas sensitivity for CT scans was 84.7% and specificity was 89.7%.There was an observed association with anatomic level, with a consistently less accuracy in detecting screw position at L1 with plain x-ray (P=0.001). Additionally, correct position of stainless steel screws was more difficult to detect as compared with titanium (P=0.033) using either x-rays or CT. Other variables examined, such as screw length and screw diameter, did not have an effect on the ability to read the positioning. CONCLUSIONS: CT scans, often considered the "gold standard" for clinical assessment of pedicle screw placement, have limitations when validated with gross anatomical dissection. The described systematic method for evaluating pedicle screw placement using orthogonal plain radiographs attained accuracy comparable to high-resolution CT scans.     

Three-dimensional,three-vector-component velocimetry of cilia-driven fluid flow using correlation-based approaches in optical coherence tomography

Microscale quantification of cilia-driven fluid flow is an emerging area in medical physiology, including pulmonary and central nervous system physiology. Cilia-driven fluid flow is most completely described by a three-dimensional, three-component (3D3C) vector field. Here, we generate 3D3C velocimetry measurements by synthesizing higher dimensional data from lower dimensional measurements obtained using two separate optical coherence tomography (OCT)-based approaches: digital particle image velocimetry (DPIV) and dynamic light scattering (DLS)-OCT. Building on previous work, we first demonstrate directional DLS-OCT for 1D2C velocimetry measurements in the sub-1 mm/s regime (sub-2.5 inch/minute regime) of cilia-driven fluid flow in Xenopus epithelium, an important animal model of the ciliated respiratory tract. We then extend our analysis toward 3D3C measurements in Xenopus using both DLS-OCT and DPIV. We demonstrate the use of DPIV-based approaches towards flow imaging of Xenopus cerebrospinal fluid and mouse trachea, two other important ciliary systems. Both of these flows typically fall in the sub-100 μm/s regime (sub-0.25 inch/minute regime). Lastly, we develop a framework for optimizing the signal-to-noise ratio of 3D3C flow velocity measurements synthesized from 2D2C measures in non-orthogonal planes. In all, 3D3C OCT-based velocimetry has the potential to comprehensively characterize the flow performance of biological ciliated surfaces.OCIS codes: (110.4500) Optical coherence tomography, (120.7250) Velocimetry, (170.3340) Laser Doppler velocimetry, (170.6480) Spectroscopy, speckle     

糖尿病大鼠骨代谢变化与立普妥、胰岛素的干预效应

目的:近年细胞培养实验发现他汀类药物可以促进骨形成,采用动物实验观察胰岛素和他汀类药物立普妥对糖尿病大鼠骨代谢的影响,为糖尿病伴骨质疏松的治疗提供实验依据。方法:实验于2005-08/2006-01在大连医科大学病理教研室完成。①实验分组:SD雄性大鼠55只,随机选择10只为空白对照组,余45只经鼠尾静脉注射链尿佐菌素造成糖尿病大鼠模型。其中40只符合造模标准,随机分为糖尿病未治疗组、胰岛素治疗组、立普妥治疗组及胰岛素 立普妥治疗组,每组10只。②实验方法:所有大鼠皆给予相同普通饮食。胰岛素治疗组及胰岛素 立普妥治疗组于实验第4天接受中效胰岛素治疗,6～8U/d分两次颈背部皮下注射。胰岛素剂量按每只鼠每周血糖进行调整。立普妥治疗组及胰岛素 立普妥治疗组于实验第4天给予立普妥1.25mg/kg灌胃。糖尿病未治疗组和空白对照组给予等量生理盐水灌胃。③实验评估:9周末用乙醚麻醉,每组取4只大鼠去眼球取血之后处死。14周末应用同样方法处死剩余大鼠。均取腰椎骨,常规脱钙石蜡包埋,行苏木精-伊红染色。骨组织形态计量学测量平均骨小梁厚度和平均骨小梁间距或弥散度。血中Ⅰ型胶原氨基端肽测定采用竞争性放射免疫检测方法(碘标记)。结果:实验期间大鼠死亡5只,其中糖尿病未治疗组1只于第3周死亡,胰岛素组2只于第6周死亡,胰岛素 立普妥治疗组2只于第7周死亡。①骨组织病理形态学变化:9周末立普妥治疗组、胰岛素 立普妥治疗组及糖尿病未治疗组光镜下见骨质疏松表现。14周末立普妥治疗组及胰岛素治疗组骨组织微观结构恢复至空白对照组水平。②平均骨小梁厚度:9周末:糖尿病未治疗组、胰岛素治疗组、立普妥治疗组及胰岛素 立普妥治疗组均明显低于空白对照组(P<0.01)。14周末:糖尿病未治疗组及胰岛素 立普妥治疗组均明显低于空白对照组(P<0.05)。③平均骨小梁间距或弥散度:9周末:糖尿病未治疗组及胰岛素 立普妥治疗组均明显高于空白对照组(P<0.05)。14周末:糖尿病未治疗组及胰岛素 立普妥治疗组均明显高于空白对照组(P<0.05)。④Ⅰ型胶原氨基端肽水平:9周末:立普妥治疗组和胰岛素 立普妥治疗组均明显高于空白对照组(P<0.01)。14周末:胰岛素治疗组、立普妥治疗组和胰岛素 立普妥治疗组均明显高于空白对照组(P<0.01)。结论:①糖尿病大鼠造模9周出现明显的骨质疏松。②糖尿病大鼠骨质变化表现为骨吸收超过骨形成作用,主要以骨吸收增强为主。③立普妥及胰岛素可以促进糖尿病大鼠骨质的形成,抑制糖尿病大鼠骨质疏松的发生发展。     

Diabetes Patients' Experiences With the Implementation of Insulin Therapy and Their Perceptions of Computer-Assisted Self-Management Systems for Insulin Therapy

Background

Computer-assisted decision support is an emerging modality to assist patients with type 2 diabetes mellitus (T2DM) in insulin self-titration (ie, self-adjusting insulin dose according to daily blood glucose levels). Computer-assisted insulin self-titration systems mainly focus on helping patients overcome barriers related to the cognitive components of insulin titration. Yet other (eg, psychological or physical) barriers could still impede effective use of such systems.

Objective

Our primary aim was to identify experiences with and barriers to self-monitoring of blood glucose, insulin injection, and insulin titration among patients with T2DM. Our research team developed a computer-assisted insulin self-titration system, called PANDIT. The secondary aim of this study was to evaluate patients’ perceptions of computer-assisted insulin self-titration. We included patients who used PANDIT in a 4-week pilot study as well as patients who had never used such a system.

Methods

In-depth, semi-structured interviews were conducted individually with patients on insulin therapy who were randomly recruited from a university hospital and surrounding general practices in the Netherlands. The interviews were transcribed verbatim and analyzed qualitatively. To classify the textual remarks, we created a codebook during the analysis, in a bottom-up and iterative fashion. To support examination of the final coded data, we used three theories from the field of health psychology and the integrated model of user satisfaction and technology acceptance by Wixom and Todd.

Results

When starting insulin therapy, some patients feared a lifelong commitment to insulin therapy and disease progression. Also, many barriers arose when implementing insulin therapy (eg, some patients were embarrassed to inject insulin in public). Furthermore, patients had difficulties increasing the insulin dose because they fear hypoglycemia, they associate higher insulin doses with disease progression, and some were ignorant of treatment targets. Patients who never used a computer-assisted insulin self-titration system felt they had enough knowledge to know when their insulin should be adjusted, but still believed that the system advice would be useful to confirm their reasoning. Furthermore, the time and effort saved with automated insulin advice was considered an advantage. Patients who had used PANDIT found the system useful if their glycemic regulation improved. Nevertheless, for some patients, the absence of personal contact with their caregiver was a drawback. While guidelines state that adjustment of basal insulin dose based on fasting plasma glucose values is sufficient, both patients who had and those who had not used PANDIT felt that such a system should take more patient data into consideration, such as lifestyle and diet factors.

Conclusions

Patients encounter multiple obstacles when implementing insulin therapy. Computer-assisted insulin self-titration can increase patient awareness of treatment targets and increase their confidence in self-adjusting the insulin dose. Nevertheless, some barriers may still exist when using computer-assisted titration systems and these systems could also introduce new barriers.