109Use of EPR Spectroscopy to Measure Tissue Oxygen in an Ischemic Flap Model

Methods to reliably measure tissue oxygenation in situ are currently lacking. We have developed a vertically oriented, dorsal, bipedicle flap model that is easy to perform, reliably reproduces tissue ischemia, eliminates craniocaudal variation, and is amenable to studying therapeutic modalities. The effect of narrowing this flap on tissue oxygenation measured with Licox electrodes has previously been presented. In this study we utilize in situ EPR spectroscopy to demonstrate the oxygen gradient in the flap as a function of flap width and placement of a silicone sheet directly under the flap. The effect of wound healing over a 2 week period is demonstrated. Twenty four, 300 gm male Sprague‐Dawley rats underwent creation of the bipedicle flap according to the following groups: 2.5 cm flap with silicone, 2.0 cm flap without silicone, 2.0 cm flap with silicone. Each group of 6 animals was injected with EMS char at 2 cm intervals along the flap and one injection in the control, non‐ischemic tissue. A 4^th group underwent 2.0 cm flaps with silicone and use of lithium phthalocyanin as the paramagnetic material. Wound measurements and EPR spectroscopy were performed on days 3, 7, 10 and 14. On day 14, after EPR measurements, the animals were sacrificed and their wounds excised. One flap and one control wound were preserved for histologic analysis, the other flap and control wounds were prepared for lactate measurements. EPR spectroscopy demonstrated a gradient of oxygen that was lowest in the center of the flap and greatest at either end. Changes in the oxygen gradient correlated with narrowing and placement of the intervening silicone sheet. This new technology has never been utilized in an animal model of impaired wound healing. Comparison of recently developed paramagnetic materials for optimal tissue oxygen and free radical measurements will be presented.     

Pheochromocytoma and the normal adrenal medulla: improved visualization with I-123 MIBG scintigraphy

The radiopharmaceutical iodine 131 metaiodobenzylguanidine (I-131 MIBG) has been shown to locate pheochromocytomas scintigraphically with a false-negative rate of approximately 13%. To improve image quality and reduce the false-negative rate, I-123 was examined as a radioactive label for MIBG, as it has many advantages over I-131, including superior dosimetry and better detection efficiency. Diagnostic doses of 0.5 mCi (18.5 MBq) I-131 MIBG and 10.0 mCi (370.0 MBq) I-123 MIBG with nearly equivalent radiation dosimetries were compared in 18 patients with known or suspected pheochromocytomas. Images of superior quality were obtained with I-123 MIBG in 18 of 18 patients, and in eight cases lesions not visualized on I-131 MIBG scintigraphy were portrayed. A further advantage of I-123 MIBG is that it permits single photon emission computed tomography (SPECT). This was performed in six cases and provided additional information in three cases. The adrenal medullae were definitely visualized using I-123 scintigraphy in eight of 14 patients still possessing adrenal glands, whereas I-131 MIBG images portrayed the adrenal medulla in only one of 14 cases. Five remaining patients had multiple abdominal tumor deposits that were difficult to differentiate from normal adrenal medullae.     

Pitfalls in MR imaging of the knee

Discrepancies between the findings of magnetic resonance (MR) imaging and those of arthroscopy were reviewed retrospectively in 52 knee examinations. Some of the discrepancies between MR imaging and arthroscopy were caused by errors in interpretation of MR images due to normal structures that mimicked meniscal tears. The transverse ligament and the lateral inferior genicular artery can produce the appearance of tears in the anterior horns of the medial and lateral menisci, respectively. The popliteus tendon may be mistaken for a tear in the posterior horn of the lateral meniscus. The normal concavity at the outer edge of the meniscus can create a volume-averaging artifact, which mimics a horizontal tear in the meniscus. Tears of the meniscus and separations of the meniscus from the joint capsule were not seen or were underestimated when the tears were oriented parallel to the plane of the image. An awareness of these pitfalls may improve the accuracy of the interpretation of MR images of the knee.     

Preliminary report: No association between TCF7L2 rs7903146 and euglycemic-clamp-derived insulin sensitivity in a mixed-age cohort

There are conflicting reports about the significance of TCF7L2 single nucleotide polymorphism rs7903146, a single nucleotide polymorphism found to be associated with type 2 diabetes mellitus in several genomewide association studies, and insulin sensitivity. The association of rs7903146 and euglycemic-clamp-derived insulin sensitivity was tested in a cohort of children and their parents. Four hundred seventy whites (from 226 families) and 89 African Americans (from 48 families) were included in the analysis. No significant associations were seen between rs7903146 and insulin sensitivity. Adjusted genotype means were consistent across races and generational subgroups.     

Respiratory symptoms in preterm infants: burden of disease in the first year of life

Objective

While respiratory symptoms in the first year of life are relatively well described for term infants, data for preterm infants are scarce. We aimed to describe the burden of respiratory disease in a group of preterm infants with and without bronchopulmonary dysplasia (BPD) and to assess the association of respiratory symptoms with perinatal, genetic and environmental risk factors.

Methods

Single centre birth cohort study: prospective recording of perinatal risk factors and retrospective assessment of respiratory symptoms during the first year of life by standardised questionnaires. Main outcome measures: Cough and wheeze (common symptoms), re-hospitalisation and need for inhalation therapy (severe outcomes). Patients: 126 preterms (median gestational age 28.7 weeks; 78 with, 48 without BPD) hospitalised at the University Children''s Hospital of Bern, Switzerland 1999-2006.

Results

Cough occurred in 80%, wheeze in 44%, rehospitalisation in 25% and long term inhalation therapy in wheezers in 13% of the preterm infants. Using logistic regression, the main risk factor for common symptoms was frequent contact with other children. Severe outcomes were associated with maximal peak inspiratory pressure, arterial cord blood pH, APGAR and CRIB-Score.

Conclusions

Cough in preterm infants is as common as in term infants, whereas wheeze, inhalation therapy and re-hospitalisations occur more often. Severe outcomes are associated with perinatal risk factors. Preterm infants who did not qualify for BPD according to latest guidelines also showed a significant burden of respiratory disease in the first year of life.     

中老年维持性血液透析患者死亡事件的原因分析

目的分析2005年1月～2011年12月在北京医院维持性血液透析死亡患者的病例特点和死亡原因。方法回顾性的检出维持血液透析大于3个月的死亡患者共83例,计算本中心从2005年起每年维持透析患者的死亡人数和死亡率;将死亡患者根据年龄分为3组,60岁以下中年组,60～79岁老年组和80岁以上高龄组,分析3组的人口学资料、有无糖尿病、透析龄和死亡原因等。结果从2005年起,北京医院每年维持透析患者的死亡率依次为11.00%,10.90%,8.30%。8.10%,10.10%,8.70%和6.34%;83例死亡患者中,男性49例,女性34例,平均年龄71.812.0岁(42岁～94)岁,中年组(小于60岁)14例,老年组(60～79)岁46例,高龄组(大于80)岁23例;3组患者在性别上无统计学差异。透析龄在中年组最长,平均77.2±73.0月,高龄组为44.0±35.5月,老年组透析龄最短,平均为33.2±28.1月;3组之间的差异有统计学意义。老年组患者糖尿病肾病居多;死亡原因在各组有明显的差别,中年组50%死于脑血管疾病,脑出血居多;高龄组56.50%死于感染中毒性休克。老年组死亡原因较复杂,死亡率超过10%的依次为感染中毒性休克、心肌梗死或心力衰竭、肿瘤、营养不良-炎症-动脉粥样硬化综合征(Malnutrition-inflammation-atherosclerosissyndrome,MIAsyndrome)和猝死。结论北京医院单中心血液透析死亡患者绝大多数为老年患者。年龄不是决定透析预后不良的主要危险因素,糖尿病是影响预后的重要因素,不同年龄组患者死亡原因不同,中年患者脑血管疾病多见,高龄患者感染中毒性休克常见,老年患者的死亡原因多样化,包括心脑血管疾病、感染、肿瘤和MIA综合征。±