Subatomic Channeling and Helicon-Type Beams in SrTiO_{3}.

Inspired by recent experimental subatomic measurements using analytical aberration-corrected scanning transmission electron microscopes, we study electron probe propagation in crystalline SrTiO_{3} at the subatomic length scale. Here, we report the existence of subatomic channeling and the formation of a helicon-type beam at this scale. The results of beam propagation simulations, which are performed at various crystal temperatures, STEM probe convergence angles (10-50 mrad), and beam energies (80-300 keV), showed that reducing the ambient temperature can enhance the subatomic channeling and STEM probe parameters can be used to control the features of helicon-type beams.

Identification of a sensitive urinary biomarker, selenium-binding protein 1, for early detection of acute kidney injury.

Acute kidney injury (AKI) is associated with increased mortality rate in patients but clinically available biomarkers for disease detection are currently not available. Recently, a new biomarker, selenium-binding protein 1 (SBP1), was identified for detection of nephrotoxicity using proteomic analysis. The aim of this study was to assess the sensitivity of urinary SBP1 levels as an early detection of AKI using animal models such as cisplatin or ischemia/reperfusion (I/R). Sprague-Dawley rats were injected with cisplatin (6 mg/kg, once i.p.) and sacrificed at 1, 3, or 5 days after treatment. Ischemia was achieved by bilaterally occluding both kidneys with a microvascular clamp for 45 min and verified visually by a change in tissue color. After post-reperfusion, urine samples were collected at 9, 24, and 48 hr intervals. Urinary excretion of protein-based biomarkers was measured by Western blot analysis. In cisplatin-treated rats, mild histopathologic alterations were noted at day 1 which became severe at day 3. Blood urea nitrogen (BUN) and serum creatinine (SCr) levels were significantly increased at day 3. Levels of urinary excretion of SBP1, neutrophil gelatinase-associated lipocalin (NGAL), and a tissue inhibitor of metalloproteinase-1 (TIMP-1) were markedly elevated at day 3 and 5 following drug treatment. In the vehicle-treated I/R group, serum levels of BUN and SCr and AST activity were significantly increased compared to sham. Urinary excretion of SBP1 and NGAL rose markedly following I/R. The urinary levels of SBP1, NGAL, TIMP-1, and KIM-1 proteins excreted by AKI patients and normal subjects were compared. Among these proteins, a marked rise in SBP1 was observed in urine of patients with AKI compared to normal subjects. Based upon receiver-operator curves (ROC), SBP1 displayed a higher area under the curve (AUC) scores than levels of SCr, BUN, total protein, and glucose. In particular, SBP1 protein was readily detected in small amounts of urine without purification. Data thus indicate that urinary excretion of SBP1 may be useful as a reliable biomarker for early diagnosis of AKI in patients.

Adjacent level ossification development after anterior cervical fusion without plate fixation.

STUDY DESIGN: A retrospective. OBJECTIVE: The proximity of the plate to the adjacent disc space appeared to be the critical determinant of adjacent level ossification development (ALOD) but we had no data on unplated arthrodesis. Without such data, we could not be positive that ALOD was a complication related to plates. SUMMARY OF BACKGROUND DATA: We previously described the incidence and timing of ALOD after anterior cervical arthrodesis and plating. METHODS: One hundred sixty-five patients (total 330 adjacent levels) who underwent anterior cervical arthrodesis without plate fixation by a single surgeon were reviewed. The average follow-up period was 28.8 months (2-9 years); ages ranged from 32 to 79 years (median 59.86). The presence and severity of ALOD was assessed on the lateral radiographs at 3, 6, 12, and 24 months after surgery and then annually and recorded into 4 grades. RESULTS: ALOD developed in 9 patients at 10 levels (5.5% of patients and 3% of levels). Eight patients had a single-level (proximal or distal) ALOD, whereas 1 patient had both ALOD. Proximal ALOD developed in 7 cases, distal in 1 case and both in 1 case. ALOD initially appeared between 6 and 12 months in all cases: 4 cases occurred at 6 months and 5 cases at 12 months. During follow-up period, the final grade of proximal ALOD was grade I for 4 levels and grade II for 4 levels and final grade of distal ALOD was grade I for 1 level and grade II for 1 level. One patient with C3-C4 arthrodesis had both ALOD with grade I proximally and grade II distally. CONCLUSION: ALOD is infrequent when certain techniques are adhered to. These include minimal stripping of the anterior longitudinal ligament and the avoidance of Caspar pins and anterior plates. It remains to be determined exactly which of these factors plays the dominant role in the production of ALOD.

The impact of adjacent segment degeneration on the clinical outcome after lumbar spinal fusion.

STUDY DESIGN: A retrospective study. OBJECTIVE: To determine the impact of the adjacent segment degeneration (ASD) on the clinical outcome after lumbar fusion. SUMMARY OF BACKGROUND DATA: Few studies have analyzed correlation between clinical outcomes and ASD. METHODS: From January 2000 to December 2004, 217 patients who underwent lumbar fusion and have more than 2 years of follow-up were evaluated. The patients were divided into 3 groups: fusion was carried out on 1 (A), 2 (B), and more than 3 segments (C). UCLA grading scale was used to evaluate the ASD on radiograph preoperative, postoperative, and last follow-up. The clinical outcome was evaluated and the association between clinical outcome and ASD was evaluated by the Spearman correlation. RESULTS: ASD occurred 11.6% (13/112 cases) in group A, 14.5% (9/62 cases) in group B, and 16.3% (7/43 cases) in group C. Among them, the cases which had progressed more than 2 level of degenerative grade were 0 in group A, 7 cases (77.8%) in group B, and 6 cases (85.7%) in group C. In group A, 5 cases with ASD had down graded 1 level in clinical outcome. In group B, all 9 cases with ASD had down graded more than 1 level in clinical outcome; 1 level aggravation in 1, 2 level in 5, and 3 level in 1 case. In group C, all 7 cases with ASD also had down graded more than 1 level in clinical outcome; 1 level aggravation in 2, 2 level in 5 cases. Finally, the more the change of the degenerative grade is severe, the more the clinical outcome is worse (P < 0.05). CONCLUSION: The impact of ASD on clinical outcome after fusion showed a significant correlation, especially with the ASD after multiple-segments fusion. Careful attention is needed in multiple-segments fusion such as degenerative lumbar deformity.