Septal-lateral annnular cinching perturbs basal left ventricular transmural strains.

OBJECTIVE: Septal-lateral annular cinching ('SLAC') corrects both acute and chronic ischemic mitral regurgitation in animal experiments, which has led to the development of therapeutic surgical and interventional strategies incorporating this concept (e.g., Edwards GeoForm ring, Myocor Coapsys, Ample Medical PS3). Changes in left ventricular (LV) transmural cardiac and fiber-sheet strains after SLAC, however, remain unknown. METHODS: Eight normal sheep hearts had two triads of transmural radiopaque bead columns inserted adjacent to (anterobasal) and remote from (midlateral equatorial) the mitral annulus. Under acute, open chest conditions, 4D bead coordinates were obtained using videofluoroscopy before and after SLAC. Transmural systolic strains were calculated from bead displacements relative to local circumferential, longitudinal, and radial cardiac axes. Transmural cardiac strains were transformed into fiber-sheet coordinates (X(f), X(s), X(n)) oriented along the fiber (f), sheet (s), and sheet-normal (n) axes using fiber (alpha) and sheet (beta) angle measurements. Results: SLAC markedly reduced (approximately 60%) septal-lateral annular diameter at both end-diastole (ED) (2.5+/-0.3 to 1.0+/-0.3 cm, p=0.001) and end-systole (ES) (2.4+/-0.4 to 1.0+/-0.3 cm, p=0.001). In the LV wall remote from the mitral annulus, transmural systolic strains did not change. In the anterobasal region adjacent to the mitral annulus, ED wall thickness increased (p=0.01) and systolic wall thickening was less in the epicardial (0.28+/-0.12 vs 0.20+/-0.06, p=0.05) and midwall (0.36+/-0.24 vs 0.19+/-0.11, p=0.04) LV layers. This impaired wall thickening was due to decreased systolic sheet thickening (0.20+/-0.8 to 0.12+/-0.07, p=0.01) and sheet shear (-0.15+/-0.07 to -0.11+/-0.04, p=0.02) in the epicardium and sheet extension (0.21+/-0.11 to 0.10+/-0.04, p=0.03) in the midwall. Transmural systolic and remodeling strains in the lateral midwall (remote from the annulus) were unaffected. CONCLUSIONS: Although SLAC is an alluring concept to correct ischemic mitral regurgitation, these data suggest that extreme SLAC adversely effects systolic wall thickening adjacent to the mitral annulus by inhibiting systolic sheet thickening, sheet shear, and sheet extension. Such alterations in LV strains could result in unanticipated deleterious remodeling and warrant further investigation.     

Physician assistants in academic radiology: the harborview experience

We describe a model of how physician assistants can be used in an academic medical center to expand radiologist productivity, and to enhance the departmental academic and educational missions. At Harborview Medical Center, following a training program and graduated responsibility under supervision, physician assistants provide initial interpretation of radiology studies, consultation to referring physicians, and perform less complicated interventional procedures. Acceptance of physician assistants by the radiologists, radiology residents, and referring physicians has been high. Although the impact of physician assistants on departmental clinical productivity is difficult to measure, our data suggest that radiologists are more efficient when physician assistants are assigned to service, both in terms of numbers of studies interpreted, and timeliness of reporting and billing. As a result of the success of our program, we believe that physician assistants can have an important role in radiology practice.     

瞬目反射及脑干听觉诱发电位对脑干梗死疗效的评价

目的探讨瞬目反射和脑干听觉诱发电位对脑干梗死患者疗效的评价作用。方法40例经临床症状、体征定位于脑干髓内并经头部MRI检查明确诊断的脑干梗死患者(脑桥梗死31例、中脑梗死4例和延髓梗死5例),分别计算治疗前后瞬目反射各成分的平均潜伏期;观察脑干听觉诱发电位波形及各波潜伏期、峰间期的变化。结果经治疗后40例患者临床症状及体征均有不同程度改善,治疗前后瞬目反射各成分平均潜伏期之间差异无统计学意义(P>0.05);3例脑桥梗死患者R1波恢复正常,临床基本痊愈。治疗前后脑干听觉诱发电位各波潜伏期及峰间期比较,差异亦无统计学意义(P>0.05);治疗后中脑梗死及脑桥梗死患者各有2例恢复正常,临床症状明显好转。结论瞬目反射与脑干听觉诱发电位均能敏感地反映脑干功能的变化,与临床表现具有一致性,但在发病15d内大部分病例的电生理活动不能恢复正常。     

关节镜下可吸收半月板箭修复膝关节半月板损伤106例疗效观察

目的:观察总结关节镜下可吸收半月板箭修复损伤半月板的术后疗效及术后并发症。对象与方法:采用镜下可吸收半月板箭复位固定法,对106例患者的108个损伤半月板进行修复。通过症状、体征、Tegner和Lysholm评分对半月板缝合修复的临床效果及术后并发症进行了观察,对术后有明显症状、体征的患者进行了关节镜探查。结果:术后随访106例、1~9·5年(平均26±12·3个月)。Tegner评分术后(7·65±2·54)较术前(3·55±1·59)有显著性差异(P<0·001)。Lysholm评分术后(88·55±25·64)较术前(35·46±14·62)有显著性差异(P<0·001)。疗效优61只半月板,占56·5%;良35只半月板,占32·4%;可8只半月板,占7·4%;差4只半月板,占3·7%。总优良率为88·9%。对术后有症状和体征的14例患者进行关节镜再探查,发现4例未愈合,5例部分愈合。术后并发症包括半月板箭固定处的后关节囊刺痛5例。无严重的血管神经损伤,106例患者术后并发症总发生率4·72%。结论:关节镜下可吸收半月板箭修复半月板损伤手术成功率较高,术中和术后风险较小。     

Impact of Increasing Margin Around the Lumpectomy Cavity to Define the Planning Target Volume for 3D Conformal External Beam Accelerated Partial Breast Irradiation

The purpose of this study was to evaluate the dose to normal tissues as a function of increasing margins around the lumpectomy cavity in accelerated partial breast irradiation (APBI) using 3D-conformal radiotherapy (3DCRT). Eight patients with Stage 0-I breast cancer underwent treatment planning for 3DCRT APBI. The clinical target volume (CTV) was defined as a 15-mm expansion around the cavity limited by the chest wall and skin. Three planning target volumes (PTV1, PTV2, PTV3) were generated for each patient using a 0, 5-, and 10-mm expansion around the CTV, for a total margin of 15, 20, and 25 mm. Three treatment plans were generated for every patient using the 3 PTVs, and dose-volume analysis was performed for each plan. For each 5-mm increase in margin, the mean PTV:total breast volume ratio increased 10% and the relative increase in the mean ipsilateral breast dose was 15%. The mean volume of ipsilateral breast tissue receiving 75%, 50%, and 25% of the prescribed dose increased 6% to 7% for every 5 mm increase in PTV margin. Compared to lesions located in the upper outer quadrant, plans for medially located tumors revealed higher mean ipsilateral breast doses and 20% to 22% more ipsilateral breast tissue encompassed by the 25% IDL. The use of 3DCRT for APBI delivers higher doses to normal breast tissue as the PTV increases around the lumpectomy cavity. Efforts should be made to minimize the overall PTV when this technique is used. Ongoing studies will be necessary to determine the clinical relevance of these findings.     

Transition from open to robotic-assisted radical prostatectomy is associated with a reduction of positive surgical margins amongst private-practice-based urologists

Several recent studies have suggested that thought leaders in radical prostatectomy have decreased their own positive margin rates by switching from open to robot-assisted radical prostatectomy. Theoretically, this improvement is largely attributed to enhanced visualization of the deep pelvis and precision of dissection afforded by the instrumentation. To date, it has not been determined if this phenomenon exists amongst non-fellowship-trained urologists in private practice. Herein, we describe the positive margin rates of two non-fellowship-trained private-practice urologists who converted from open radical retropubic prostatectomy to robot-assisted radical prostatectomy. The margin positivity data from two non-fellowship-trained private-practice urologists (surgeon 1 and surgeon 2) were reviewed retrospectively. The last 50 cases of open radical retropubic prostatectomy from each surgeon were compared with the first 50 robotic prostatectomy cases of surgeons 1 and 2, respectively. A positive surgical margin was defined as tumor present at the inked margin of the prostate. There was a significant decrease in the overall and pT2 positive margin rates for both surgeons. The overall positive margin rate and pT2 positive margin rate for surgeon 1 dropped from 44 to 20% and from 37 to 5.7%, respectively, after changing from open to robotic prostatectomy. For surgeon 2, the overall positive margin rate changed from 26 to 18% and the pT2 positive margin rate changed from 27.5 to 7% after converting. Changing from open to robotic-assisted radical prostatectomy may improve the ability of urologists to obtain negative surgical margins. With proper training this phenomenon does seem to apply to non-fellowship-trained urologists in private practice and can be realized within the first 50 cases performed.     

Effect of AVP on brain edema following traumatic brain injury

Objective: To evaluate plasma arginine vasopressin (AVP) level in patients with traumatic brain injury and investigate the role of AVP in the process of brain edema. Methods: A total of 30 patients with traumatic brain injury were involved in our study. They were divided into two groups by Glasgow Coma Scale: severe traumatic brain injury group (STBI, GCS≤8) and moderate traumatic brain injury group ( MTBI, GCS >8). Samples of venous blood were collected in the morning at rest from 15 healthy volunteers (control group) and within 24 h after traumatic brain injury from these patients for AVP determinations by radioimmunoassay. The severity and duration of the brain edema were estimated by head CT scan. Results: plasma AVP levels (ng/L) were (mean±SD): control, 3. 06±1. 49; MTBI, 38. 12±7. 25; and STBI, 66. 61±17. 10. The plasma level of AVP was significantly increased within 24 h after traumatic brain injury and followed by the reduction of GCS, suggesting the deterioration of cerebral injury (P<0. 01). And the AVP level was correlated with the severity (STBI r =0.919, P < 0.01; MTBI r = 0.724, P < 0.01) and the duration of brain edema (STBI r = 0. 790, P < 0. 01; MTBI r = 0. 712, P<0.01). Conclusions: The plasma AVP level is closely associated with the severity of traumatic brain injury. AVP may play an important role in pathogenesis of brain edema after traumatic brain injury.     

Distinct phases in recovery of reconstituted innate cellular-mediated immunity after murine syngeneic bone marrow transplantation.

Defects in immune reconstitution after hematopoietic stem cell transplantation confer extreme infection risk on to the transplant recipient. Perturbations in adaptive immune reconstitution have been well characterized, yet defects in reconstituted innate cellular-mediated immunity remain largely unstudied. Recovery in innate effector cells was defined by using an established murine model of autologous bone marrow transplantation. Cytokine induction after cell culture and systemic stimulation with pathogen-associated molecular patterns was also measured for control, transplant-recipient, and irradiated-only animals. Early reconstitution (7 to 14 days) of donor-derived macrophages, dendritic cells, and polymorphonuclear cells was associated with recovery in interleukin (IL)-12p70 and IL-6 production. Later reconstitution (21 days) of natural killer cells was associated with interferon (IFN)-gamma recovery. Hence, splenocyte innate cellular-mediated immunity recovered to normal levels in cellularity and IL-12p70, IFN-gamma, and IFN-alpha production by 21 days after transplantation. In contrast, levels of systemic cytokine production from transplant-recipient and irradiated-only animals were preserved despite incomplete or absent hematopoietic reconstitution. These results suggest that innate immune responses to systemic inflammatory challenges are largely intact after autologous bone marrow transplantation, whereas local innate cellular-mediated immunity within reconstituting lymphoid organs may be impaired. The disparate effects of autologous hematopoietic stem cell transplantation on host immune function may translate to differences in susceptibility to local versus systemic infectious challenges.