急性主动脉夹层腔内修复覆盖左锁骨下动脉的疗效观察

目的：探讨急性主动脉夹层腔内修复术（TEVAR）中覆盖左锁骨下动脉（LSA）的安全性。 方法：回顾性分析我院心血管外科2010年1 月— 2016年6月99例行急性主动脉夹层腔内修复术（T E V A R） 患者资料。其中L S A 未封堵53例，部分封堵19例，完全封堵27例。分析比较L S A 封堵与未封堵及完全封堵患者围手术期脑卒中及截瘫发生率；随访患者术后远期左上肢缺血症状及脑卒中发生率。 结果：所有患者住院期间均无左上肢缺血性疼痛； 3 例（3%）术后发生短暂性脑缺血发作及一过性黑曚，其中2 例（2%）LSA 未封堵，1 例（1%）LSA 封堵；围手术期无截瘫病例。平均随访37.7（2~73）个月，随访结果及统计分析显示，LSA 封堵可能增加中期脑卒中发生率，患者双上肢血压差及左上肢缺血症状有差异。 结论： LSA封堵不增加TEVAR术围手术期脑卒中及截瘫风险，可能增加术后远期脑卒中风险；为缓解左上肢远期缺血症状，可能需要择期行LSA血运重建。     

Hybrid技术应用于Stanford B型主动脉夹层的近期疗效

目的探讨腔内隔绝术联合血管旁路移植术（Hybird技术）治疗破口位于弓部的StanfordB型主动脉夹层（AD）近期疗效。方法选择武汉亚洲心脏病医院2008年8月至2012年6月收治的StanfordB型AD37例,均采取腔内隔绝术,并在其术前行血管旁路移植术。其中男33例,女4例,年龄36-71（51．84±9．21）岁。主动脉夹层第一破口距左颈总动脉或左锁骨下动脉开口处均小于15mm。27例行右颈总动脉-左颈总动脉旁路移植术,2例行右颈总动脉一右锁骨下动脉旁路移植术,6例行左颈总动脉-左锁骨下动脉移植术,2例行左颈总动脉-左腋动脉移植术（左锁骨下动脉开口及近端均被夹层血肿挤压）。术后立即转人介入导管室行腔内隔绝术。共置入带膜支架42枚（双支架5例,其中4例应用带膜支架加裸金属支架）。结果（1）37例行血管旁路移植术及腔内隔绝术均顺利。术后8—24（17．97±3．88）d出院。其中1例院内死亡,近期死亡1例（随访证实出院后当日死亡,等同于近期）。其余病例均无内漏、截瘫、内脏器官缺血、脑部缺血和左上肢缺血症状,随访30d,均恢复良好。（2）术后11例出现发热,排除感染因素,考虑为腔内隔绝术后综合征,经对症处理后恢复。2例因人工血管吻合口出血再次行吻合术。2例新出现肾功能不全,分析为对比剂肾病,经治疗后恢复。术后有5例仍有胸背痛症状,复查主动脉增强CT无内漏出血,治疗后均好转出院。结论腔内隔绝术联合血管旁路移植术治疗累及主动脉弓的StanfordB型主动脉夹层是一种创伤小、疗效好的治疗方法。     

108例支架近端锚定区不足患者胸主动脉覆膜支架置入术治疗分析

目的探讨胸主动脉覆膜支架置入术在支架近端锚定区不足时左锁骨下动脉的处理方法及支架直接覆盖左锁骨下动脉开口的安全性。方法回顾分析支架近端锚定区不足的108例胸主动脉病变(B型夹层94例,假性动脉瘤14例)左锁骨下动脉的处理方法、结果及并发症。2例行人工血管旁路联合覆膜支架置入术(杂交手术),其余患者直接行覆膜支架置入术,其中,完全覆盖左锁骨下动脉开口72例(A组),部分覆盖左锁骨下动脉开口34例(B组)。对比两组术后内漏、LSA显影、双上肢收缩期压差等结果。结果支架均顺利置入,术后除1例出现脑供血不足,死于呼吸循环衰竭,余患者均未出现神经系统并发症及左上肢严重缺血症状。A组左上肢收缩期血压低于右侧(84.8±44.0)mmHg和(130.8±21.4)mmHg,差异具有统计学意义;B组双上肢收缩期血压差异无统计学意义。随访(31.3±23.7)个月,仅A组中33例出现轻微左上肢乏力、麻木及头晕症状,无需手术处理。结论胸主动脉覆膜支架置入术中近端锚定区不足时,直接覆盖左锁骨下动脉开口以延长锚定区是可行的,特别是部分覆盖LSA开口更为安全;但必需严格把握适应证、仔细评估双侧椎动脉及颈动脉血供情况,对合并脑梗塞、呼吸睡眠暂停综合征等影响脑供血疾病的患者即使右侧椎动脉及双侧颈动脉血供良好,也不宜直接完全覆盖LSA开口。     

预开窗胸腔血管内修复术治疗胸主动脉病变的临床疗效

目的探讨预开窗胸腔血管内修复术(PF-TEVAR)在近端锚定区不足时左锁骨下动脉(LSA)的处理方法及疗效。方法选择2017年4月至2018年11月深圳市孙逸仙心血管医院,心血管外科收治近端锚定区不足的51例胸主动脉病变患者,所有患者均采取PF-TEVAR技术进行治疗,观察脑及上肢缺血并发症发生情况。术后评价支架有无内漏、移位和3分支显影情况等。结果 51例患者,术中对位失败1例(2.0%),围手术期内漏6例(11.8%),死亡1例(2.0%)。术后随访1～20个月,随访期间失访6例(11.8%),死亡1例(2.0%)。患者复查CT血管成像,主动脉覆膜支架形态良好,无支架移位,支架内血流通畅。LSA狭窄或闭塞5例。结论胸主动脉病变近端锚定区不足时,PF-TEVAR技术可延长锚定区并保持LSA通畅,拓展了胸主动脉病变腔内治疗的适应证。     

单分支主动脉支架在锚定区不足的胸主动脉腔内修复术中的应用

目的：研究单分支主动脉支架在锚定区不足的胸主动脉腔内修复术的应用。方法：回顾性分析2019年10月至2021年10月，于内蒙古医科大学附属医院心脏大血管外科收治的18例锚定区不足的主动脉疾病患者临床资料。结果：男性14例，女性4例，年龄（57.1±13.5）岁，体质量（78.6±5.1）kg，包括急性Standford B型主动脉夹层10例，主动脉穿透性溃疡6例，胸主动脉假性动脉瘤2例。手术时间（2.6±0.4）h，成功率100%，无内漏，无围术期死亡，无神经系统及上肢缺血并发症。随访时间12个月，所有患者主动脉及分支支架通畅率为100%，支架近端无明显内漏，假腔均出现血栓化，无神经系统及左上肢缺血表现。结论：对近端锚定区不足的主动脉疾病患者应用单分支主动脉支架行胸主动脉腔内修复安全有效，左锁骨下动脉重建效果良好，中长期效果需要继续评估。     

胸主动脉病变腔内修复术合并“烟囱”支架置入术后内漏情况分析

目的:探讨Standford B型主动脉病变在近端锚定区不足时,置入覆膜支架行胸主动脉腔内修复术(TEVAR)合并"烟囱"支架处理受累的左颈总动脉或左锁骨下动脉时,术中发生内漏的情况及其与病变位置之间的关系、手术疗效及预后。方法:回顾性分析2011-09至2015-07我院收治的Standford B型主动脉病变在近端锚定区不足的患者32例,采用置入覆膜支架行TEVAR合并"烟囱"支架治疗,观察术后即刻左颈总动脉或左锁骨下动脉显影、神经系统并发症及左上肢严重缺血症状、内漏情况,并术后随访3~46个月神经系统并发症及左上肢严重缺血症状、内漏情况。结果:32例患者TEVAR合并"烟囱"支架均成功。术后即刻左颈总动脉或左锁骨下动脉均显影良好,患者均未出现神经系统并发症及左上肢严重缺血症状,主动脉弓发生内漏7例,其中病变位于主动脉弓大弯侧6例,病变位于主动脉弓小弯侧1例。术后随访3~46个月,主动脉覆膜支架形态良好,"烟囱"支架内血流通畅,7例发生内漏患者中5例内漏逐渐减小、消失,2例持续存在。结论:Standford B型胸主动脉病变在近端锚定区不足时,"烟囱"支架可延长锚定区并保持左颈总动脉或左锁骨下动脉通畅,更为安全地拓展了胸主动脉病变腔内治疗的适应证,达到微创、安全、有效的目的,但当破口位于主动脉弓大弯侧时,"烟囱"支架可能增加内漏发生几率。     

胸主动脉钝性外伤的腔内修复治疗

目的 探讨腔内修复技术在治疗胸主动脉钝性外伤中的可行性和安全性.方法 回顾分析2010年2月至2013年12月期间7例胸主动脉钝性外伤患者的临床资料.术前CTA及术中造影评估病变,回顾术中技术成功率,死亡及截瘫等主要并发症的发生率.术后CTA随访明确有无内漏、支架移位等情况.结果 所有创伤都累及主动脉峡部,包括Stanford B型夹层1例、降主动脉假性动脉瘤6例.全部患者均接受覆膜支架腔内修复治疗,其中1例先行左-右锁骨下动脉转流术.术中6例部分或全部覆盖左锁骨下动脉开口.所有手术患者均获得技术成功,无死亡及截瘫发生.术后随访时间2～28个月,无左上肢缺血症状及神经系统并发症,支架无内漏及移位.结论 腔内修复治疗胸主动脉夹层安全、有效,可行性高.     

腔内隔绝术治疗胸主动脉假性动脉瘤16例临床分析

目的探讨主动脉假性动脉瘤的临床特征,评价腔内隔绝术治疗主动脉假性动脉瘤的疗效及安全性。方法 2008年7月至2013年9月于沈阳军区总医院行主动脉腔内隔绝术治疗主动脉假性动脉瘤的患者16例。男13例,女3例,年龄(61.2±11.5)岁。经股动脉切开植入覆膜支架封堵主动脉假性动脉瘤破口,主动脉造影确认疗效;合并严重冠状动脉狭窄的患者,于腔内隔绝术后3~7 d完成经皮冠状动脉介入治疗(PCI)。观察主动脉疾病患者介入治疗的疗效。结果主动脉腔内隔绝术操作成功率为100%,共植入14枚主体覆膜支架及4枚短体覆膜支架,16例患者均无残余内漏。1例患者部分封闭左锁骨下动脉开口,左上肢血供无缺血症状。2例冠状动脉严重病变患者,1例行冠状动脉旁路移植术,1例行植入支架治疗。围术期无出血、心肌梗死、死亡等并发症。术后平均随访(68±29)个月,随访率为87.5%(14/16)。1例患者术后3个月发生脑出血,1例患者术后6个月发现胃癌化疗治疗病情稳定,于术后12个月发生截瘫,目前已失去行动能力。冠心病患者无心绞痛发作,无复查冠状动脉造影患者,无MACE发生。随访期间共死亡患者4例(25%),明确主动脉血管破裂死亡2例(12.5%)。结论主动脉腔内隔绝术治疗主动脉假性动脉瘤,创伤小、近期及长期疗效好,并发症低。合并冠心病患者择期二次行PCI安全可行。     

单中心主动脉腔内隔绝术治疗胸降主动脉扩张性疾病的疗效评价

目的 评价主动脉腔内隔绝术治疗胸降主动脉扩张性疾病的近期和远期疗效及安全性.方法 选择沈阳军区总医院2002年4月至2013年10月行主动脉腔内隔绝术治疗胸降主动脉扩张性疾病的患者449例,其中男349例,女100例,年龄（54.3±11.9）岁.经股动脉切开植入覆膜支架封堵胸降主动脉夹层破口或隔绝胸主动脉瘤,主动脉造影确认疗效;合并严重冠状动脉狭窄的患者,于腔内隔绝术后3-7 d完成经皮冠状动脉介入（percutaneous coronary intervention,PCI）治疗.观察主动脉疾病患者PCI治疗的疗效.结果 主动脉腔内隔绝术操作成功率为100％,共植入416枚主体覆膜支架及56枚短体覆膜支架.43例患者完全封闭左锁骨下动脉开口,仅1例患者出现严重窃血综合征,行血管旁路移植术.34例患者行PCI治疗成功率为100％,对37支靶血管共植入45枚冠状动脉支架,无出血、心肌梗死等并发症.68例患者出现腔内隔绝术后综合征,76例患者术后有残余漏,其中11例因内漏明显同台或再次行手术治疗.住院期间主动脉破裂病死率为1.3％（6/449）.术后随访（68±29）个月,随访率为79.0％（350/443）.随访期间共死亡患者23例（6.6％）：明确主动脉血管破裂死亡4例,急性心肌梗死1例,脑出血4例,肾功衰竭死亡3例,多器官功能衰竭2例,恶性肿瘤4例,猝死5例（原因不明）.25例联合PCI治疗患者临床造影随访主要心血管事件发生率为8.0％（2/25）.结论 主动脉腔内隔绝术治疗胸降主动脉扩张性疾病近期及长期疗效好,并发症发生率低.合并冠状动脉粥样硬化性心脏病患者择期二次行PCI治疗安全可行,主要心血管事件发生率低.     

腔内修复治疗36例复杂性急性Stanford B型主动脉夹层的短期临床疗效分析

目的:探讨腔内修复治疗复杂性急性Stanford B型主动脉夹层的短期临床疗效。方法:回顾性分析我院2010-01至2014-06期间行腔内修复治疗的36例复杂性急性Stanford B型主动脉夹层患者的临床资料(包括手术情况及术后计算机断层摄影术血管造影随访情况),其中男性27例,女性9例;年龄41~62(平均43.7)岁。结果:36例患者的腔内修复均获成功。22例行主动脉腔内修复并覆盖左锁骨下动脉开口,10例结合左锁骨下动脉"烟囱"技术行主动脉腔内修复,2例先实施左颈总动脉—左锁骨下动脉人工血管转流后再行腔内修复,2例先实施右颈总动脉—左颈总动脉人工血管转流(左颈总动脉近心端结扎)后再行主动脉腔内修复。内脏动脉及下肢动脉缺血逐渐恢复,无内漏等并发症发生。36例患者中30例患者获得随访,随访率83.33%,随访时间1年。术后1年主动脉夹层全部假腔内血栓形成者10例,部分假腔内血栓形成者20例。与术前比较,术后1年无论是全部假腔内血栓形成者,还是部分假腔内血栓形成者,胸主动脉真腔体积均显著增大[(190.0±68.7)ml vs(125.3±63.4)ml和(166.2±71.8)ml vs(110.1±62.7)ml],差异均有统计学意义(P0.001);而胸主动脉假腔体积均显著缩小[(65.0±67.4)ml vs(185.3±66.6)ml和(132.3±62.6)ml vs(224.5±72.3)ml],差异均有统计学意义(P0.001)。对于全部假腔内血栓形成者,与术前比较,术后1年腹主动脉真腔体积显著增大[(55.5±12.4)ml vs(48.6±12.2)ml,P0.01];部分假腔内血栓形成者,术后1年腹主动脉假腔体积也显著增大[(58.2±21.5)ml vs(42.5±18.5)ml,P均0.01],差异均有统计学意义。结论:对于复杂的主动脉夹层患者行腔内修复,术中结合覆盖左锁骨下动脉、烟囱技术以及小切口的杂交技术等方法可延长锚定区,拓展主动脉夹层的腔内治疗范围,提高腔内修复的疗效,降低并发症的发生,短期疗效良好。     

胰岛素瘤的解剖分布特点分析

目的胰岛素瘤是最常见的胰腺神经内分泌肿瘤，因其临床表现多样，导致诊断困难。影像学诊断尤其是超声内镜(EUS)在胰岛素瘤的诊断中起着重要作用，拥有较高的敏感性和特异性。本研究拟通过明确胰岛素瘤的解剖分布特点，以期有助于提高影像学的诊断准确率和降低漏诊率，尤其是在教育和培训实践中对于EUS的学习者更具有指导价值。 方法回顾性分析解放军总医院第一医学中心病案资料数据库1993年1月至2019年11月经外科手术、病理确诊为胰岛素瘤的患者的临床资料，检索方法采取搜索术后病理诊断为"胰岛素瘤"的病例，通过查阅病例的方法，提取出胰岛素瘤的大小和解剖分布等数据，进一步分析其特点。 结果共检索到确诊为胰岛素瘤的患者116例，其中，男45例、女71例，年龄13～76岁，平均年龄(44.4±14.85)岁。胰岛素瘤单发110例(94.8%)、多发6例(5.2%)。位置分布：头颈部46例(39.7%)，单发45例、多发1例；体尾部68例(58.6%)，单发65例、多发3例；全胰腺多发2例(1.7%)。病变大小特点：最大径0.4～3.4 cm，平均大小(1.53±0.58)cm。≤1 cm 29例、>1 cm而≤1.5 cm41例、>1.5 cm而≤2.0 cm28例，≤3 cm 15例，>3 cm 3例。年龄与肿瘤的大小相关，≤44岁患者肿瘤平均大小为(1.36±0.51)cm、>44岁患者肿瘤平均大小为(1.70±0.60)cm，P<0.05。头颈部的肿瘤大于体尾部的肿瘤，头颈部肿瘤平均大小(1.66±0.63)cm，体尾部(1.42±0.52)cm，P<0.05。 结论胰岛素瘤在胰腺体尾部较头颈部更好发；绝大多数单发，但可以全胰腺多发；多数小于1.5 cm，肿瘤的大小与患者年龄和肿瘤的解剖分布相关。     

Pathogenesis of carcinoma of the papilla of Vater

Most adenomas and carcinomas of the small intestine and extrahepatic bile ducts arise in the region of the papilla of Vater. In familial adenomatous polyposis (FAP) it is the main location for carcinomas after proctocolectomy. In many cases symptoms due to stenosis lead to diagnosis at an early tumor stage. In about 80%, curative intended resection is possible. Operability is the most relevant prognostic factor. Most ampullary carcinomas resp. carcinomas of the papilla of Vater develop from adenomatous or flat dysplastic precursor lesions. They can be sited in the ampulloduodenal part of the papilla of Vater, which is lined by intestinal mucosa. They also can develop in deeper parts of the ampulla, which are lined by pancreaticobiliary duct mucosa. Intestinal-type adenocarcinoma and pancreaticobiliary-type adenocarcinoma represent the main histological types of ampullary carcinoma. Furthermore, there exist unusual types and undifferentiated carcinomas. Many carcinomas of intestinal type express the immunohistochemical marker profile of intestinal mucosa (keratin 7?, keratin 20+, MUC2+). Carcinomas of pancreaticobiliary type usually show the immunohistochemical profile of pancreaticobiliary duct mucosa (keratin 7+, keratin 20?, MUC2?). Even poorly differentiated carcinomas, as well as unusual histological types, may conserve the marker profile of the mucosa they developed from. These findings underline the concept of histogenetically different carcinomas of the papilla of Vater which develop either from intestinal- or from pancreaticobiliary-type mucosa of the papilla of Vater. Molecular alterations in ampullary carcinomas are similar to those of colorectal as well as pancreatic carcinomas, although they appear at different frequencies. In future studies, molecular alterations in ampullary carcinomas should be correlated closely with the different histologic tumor types. Consequently, the histologic classification should reflect the histogenesis of ampullary tumors from the two different types of papillary mucosa.     

Demonstration of the mechanism of action of biguanides

Summary Palmitic acid oxidation in rat diaphragm homogenate is depressed by biguanide concentrations that are still incapable of inhibiting oxidative phosphorylation. Glucose oxidation is not directly effected by the same biguanide concentrations: however, the inhibitory effect of palmitic acid on glucose oxidation is partly removed by biguanides. Inhibition of fatty acid oxidation, which accounts for most of the metabolic effects caused by these drugs, can be regarded as the fundamental mechanism of action of biguanides. There is some evidence suggesting that these drugs might interact with carnitine, thus preventing long-chain fatty acids from being transported across the mitochondrial membrane to the site of oxidation. Traduzione a cura degli AA.     

Lack of correlation of degree of villous atrophy with severity of clinical presentation of coeliac disease

BACKGROUND AND AIM: Both the clinical presentation and the degree of mucosal damage in coeliac disease vary greatly. In view of conflicting information as to whether the mode of presentation correlates with the degree of villous atrophy, we reviewed a large cohort of patients with coeliac disease. PATIENTS AND METHODS: We correlated mode of presentation (classical, diarrhoea predominant or atypical/silent) with histology of duodenal biopsies and examined their trends over time. RESULTS: The cohort consisted of 499 adults, mean age 44.1 years, 68% females. The majority had silent coeliac disease (56%) and total villous atrophy (65%). There was no correlation of mode of presentation with the degree of villous atrophy (p=0.25). Sixty-eight percent of females and 58% of males had a severe villous atrophy (p=0.052). There was a significant trend over time for a greater proportion of patients presenting as atypical/silent coeliac disease and having partial villous atrophy, though the majority still had total villous atrophy. CONCLUSIONS: Among our patients the degree of villous atrophy in duodenal biopsies did not correlate with the mode of presentation, indicating that factors other than the degree of villous atrophy must account for diarrhoea in coeliac disease.     

血吸虫童虫生长发育及其机制的研究进展

血吸虫童虫是宿主免疫系统攻击的重要靶标,包括皮肤型、肺型和肝门型童虫。宿主分子对童虫生长发育具有重要作用。童虫生长发育机制包括免疫调节、信号转导、性别发育及凋亡等。肌动蛋白、组织蛋白酶、烯醇化酶和葡萄糖基转移酶等分子为血吸虫童虫生长发育的重要分子。本文对血吸虫童虫生长发育及其机制的研究进展做一综述。     

氯硝柳胺悬浮剂的毒性评价

目的评价氯硝柳胺悬浮剂的毒性，为现场大规模应用灭螺提供依据。方法按照中华人民共和国国家标准GB 15670-1995《农药登记毒理学试验方法》和鱼类毒性试验方法进行。结果经口、经皮肤的LDso雌、雄性大鼠均>5 000 mg/kg，经呼吸道的LCso雌、雄性大鼠均>5 000mg/m3，该药经口、经皮肤、经呼吸道毒性均属微毒类药物；兔眼用药后，观察期内无不良反应，对眼无刺激性；皮肤用药后对皮肤无刺激性。与氯硝柳胺原药、氯硝柳胺乙醇胺盐原药和氯硝柳胺乙醇胺盐可湿性粉剂相比，氯硝柳胺悬浮剂对鱼急性毒性最低。结论氯硝柳胺悬浮剂属微毒类药物，对鱼的毒性低于其乙醇胺盐可湿性粉剂，适合于现场应用。     

124例耐多药结核分枝杆菌基因突变特征分析

目的对临床分离的耐多药结核分枝杆菌相关基因的突变特征进行分析。方法对124例耐多药结核分枝杆菌以及50株敏感株的耐药相关基因(包括异烟肼inh A、kat G、oxyR-ahp C间隔区以及利福平rpo B)进行序列测定,分析其基因突变情况。结果异烟肼耐药inh A基因突变率为14.5%;kat G基因突变率为70.2%(87/124),主要位于315位;oxyR-ahp C间隔区突变率为15.3%;inh A、kat G两种基因同时突变率75.0%,三种基因同时突变率为89.5%。利福平rpo B基因突变的检出率高达95.2%,突变主要发生在531、526、516位点。结论我省耐多药菌异烟肼耐药相关基因最常见突变为kat G 315、inh A C-T(-15)、axyR-ahp C间隔区(-10)C-T,利福平为rpo B531、526、516。结合MDR-TB耐药相关基因的特征分析,可以建立一种快速、准确、特异的适合于我省的检测结核菌耐多药性的新方法。     

Assessment of quality of life of parents of children with juvenile chronic arthritis

The aim of the study was to assess the quality of life (QOL) and the psychological status of parents of children with juvenile chronic arthritis (JCA). The QOL, anxiety and depression of the parents of 28 children with JCA were evaluated and compared to those of the parents of 28 healthy children. Mothers of JCA children and mothers of healthy children reported similar QOL. The reported anxiety and depression levels were similar for mothers and fathers in both groups. The parents of children with pauciarticular-type JCA reported lower QOL and higher levels of anxiety and depression than the parents of children with other types, namely polyarticular and systemic JCA. These findings may be explained by the fact that the pauciarticular patients had shorter disease duration and were less frequently seen in the outpatient clinic. The QOL of mothers of children with JCA was found to be slightly impaired in the group of children with pauciarticular JCA. Future larger studies are needed to confirm these results, as the number of subjects in the three groups was rather low. Received: 26 September 2001 / Accepted: 8 February 2002     

Numerical Simulation of the Effect of Rate of Change of Glucose on Measurement Error of Continuous Glucose Monitors

Background

A 5-day in-patient study designed to assess the accuracy of the FreeStyle Navigator® Continuous Glucose Monitoring System revealed that the level of accuracy of the continuous sensor measurements was dependent on the rate of glucose change. When the absolute rate of change was less than 1 mg•dl⁻¹•min⁻¹ (75% of the time), the median absolute relative difference (ARD) was 8.5%, with 85% of all points falling within the A zone of the Clarke error grid. When the absolute rate of change was greater than 2 mg•dl⁻¹•min⁻¹ (8% of the time), the median ARD was 17.5%, with 59% of all points falling within the Clarke A zone.

Method

Numerical simulations were performed to investigate effects of the rate of change of glucose on sensor measurement error. This approach enabled physiologically relevant distributions of glucose values to be reordered to explore the effect of different glucose rate-of-change distributions on apparent sensor accuracy.

Results

The physiological lag between blood and interstitial fluid glucose levels is sufficient to account for the observed difference in sensor accuracy between periods of stable glucose and periods of rapidly changing glucose.

Conclusions

The role of physiological lag on the apparent decrease in sensor accuracy at high glucose rates of change has implications for clinical study design, regulatory review of continuous glucose sensors, and development of performance standards for this new technology. This work demonstrates the difficulty in comparing accuracy measures between different clinical studies and highlights the need for studies to include both relevant glucose distributions and relevant glucose rate-of-change distributions.     

Study of constancy of hydrogen-consuming flora of human colon

The constancy of the hydrogen consuming flora of the human colon was studied in 15 healthy subjects via two measurements obtained 18 to 36 months apart. Hydrogen disappearance rate and the major products of H₂-consuming bacteria, methane and sulfide, were measured during incubation of fecal homogenates with excess hydrogen and sulfate. In 11/15, the hydrogen consumption rate and the predominant hydrogen-consuming pathway (methanogenesis, sulfate reduction, or neither) remained constant. However, major shifts in these pathways were observed in four subjects, with two losing and two gaining the ability to produce methane. Methanogenesis was associated with the highest hydrogen consumption rate. This study demonstrates that clinically unrecognizable, major alterations of the colonic flora occur in healthy subjects. Understanding of the factors responsible for these alterations might allow for therapeutic manipulation of the colonic flora.Supported in part by the Department of Veterans Affairs and NIDDKD RO1 DK 13309-25.