PPAR-α激动剂对大鼠内皮功能不全的作用及机制探讨

目的:观察PPAR-α激动剂对高脂血症模型大鼠内皮功能不全的作用,并初步探讨其作用机制。方法:称重后,32只SD雄性大鼠随机分成4组,每组8只:正常对照组(A组);正常+非诺贝特治疗组(B组);高脂组(C组);高脂+非诺贝特治疗组(D组)。每周称体重,按体重调整饲料及药物量。12周后,分别检测血脂4项(TC、TG、LDL-c、HDL-c)及血清中NO含量。分离胸主动脉,检测组织匀浆中总NOS活性及离体血管环的舒缩功能。结果:在调脂方面,PPAR-α激动剂非诺贝特能显著降低TG,并能在一定程度上降低LDL,同时显著升高HDL的作用。此外,PPAR-α激动剂非诺贝特具有显著增加总NOS活性及升高NO含量的作用,能显著改善内皮依赖性舒张功能,其作用并不完全依赖于血脂的降低。结论:PPAR-α激动剂非诺贝特能显著增加总NOS活性从而升高NO含量及改善血管内皮依赖性舒张功能,对内皮功能不全起到预防及治疗的作用,这可能是来自于调脂以外的作用。     

过敏性紫癜、紫癜性肾炎患儿血清VEGF、TNF-α水平变化及临床意义

目的：探讨过敏性紫癜（HSP）、紫癜性肾炎（HSPN）患儿血清血管内皮生长因子（VEGF）及肿瘤坏死因子-α（TNF-α）的水平变化及其在HSP发病与肾损害严重程度中的作用。方法：采用酶联免疫吸附法分别检测38例HSP患儿、40例HSPN及16例正常儿童血清VEGF、TNF-α水平；HSPN患儿同时测定血清尿素氮、肌酐、尿微量白蛋白（MA）和24h尿蛋白定量，分析血清VEGF、TNF-α浓度与上述指标的相关关系。结果：①HSP、HSPN患儿血清VEGF、TNF-α浓度均高于正常儿童（P〈0．05）。②HSPN患儿其血清VEGF、TNF-α浓度高于HSP组（P〈0．05）。③HSPN组的血清VEGF、TNF-α与尿MA及24h尿蛋白定量呈正相关关系（P〈0．05）。④肾活检显示，血浆VEGF、TNF-α水平与肾脏病理损害、血管损害呈正相关。结论：VEGF和TNF-α在儿童HSP的发生与发展中发挥一定的作用,血清VEGF和TNF-α浓度动态变化对临床小儿HSPN的病情判断、疗效及预后评价具有一定的指导意义。     

~(125)I-α-苦瓜子蛋白的大鼠药代动力学研究

本文采用同位素示踪技术对~(125)Ⅰ-α-苦瓜子蛋白进行药代动力学研究。药物经小鼠腹腔内吸收较快,给药后2h 吸收82.3%。大鼠静脉给药后的主要药代参数T_1/2α=1.61±0.41(h),T1/2β=48.98±8.02(h),V_c=30.94±4.18(dpm/kg),K_(21)=0.084±0.032(1/h),K_(10)=0.072±0.020(1/h),K_(12)=0.23±0.08(1/h)。消除相半衰期较长,说明药物排除缓慢。药物生物利用度76.6%,提示α-苦瓜子蛋白在体内易吸收。大鼠静脉注入~(125)Ⅰ-α-苦瓜子蛋白后,血中放射性-时间数据经拟合符合二室开放动力学模型。放射性分布结果证实,最高是肾,其次为胚胎、卵巢、子宫、肝、脂肪等组织。药物主要经尿排泄,给药24h 后,排出剂量的67.3%。胆汁排泄证实此药不易形成肠肝循环。用Sephadex G-75柱层析方法证实,代谢产物仍保持原有分子大小,未被降解。     

Arcuate ligament vascular compression syndrome in infants and children

Background

Arcuate ligament vascular compression syndrome has not been described previously in the pediatric or pediatric surgical literature. However, it is mentioned in the literature of vascular and general surgery and in journals of radiology and orthopedics. In this review, the intraoperative pathological anatomy and the principles of treatment for 8 children will be presented.

Methods

The chart records and the anatomical sketches that were documented by the surgeon immediately after each procedure were analyzed retrospectively. In addition, preoperative courses and long-term follow-up (range, 3-18 years) were evaluated by a defined program.

Results

The diagnosis of celiac artery compression by an arcuate ligament was suspected in children presenting with a history of several years of recurrent acute abdominal pain associated with a typical arterial bruit in the midline of the epigastric region.

Conclusions

Other diseases with recurrent abdominal pain and an arterial bruit must be excluded before making the decision for an operative intervention. Duplex ultrasound and angiography are possibly helpful tools to establish the respective diagnosis, but in the patients of the present series, these techniques neither confirmed compression of the celiac axis nor demonstrated decreased perfusion of the superior mesenteric artery. However, as the clinical symptoms clearly announce the disease, these diagnostic measures are not mandatory.     

Corrosion behavior of Cu and the Cu-Zn-Al shape memory alloy in simulated uterine fluid

Chemical immersion tests, electrochemical methods and atomic absorption spectrometry were employed to investigate the corrosion behavior of Cu and the Cu-Zn-Al shape memory alloy (SMA) in simulated uterine fluid. The effect of pH on corrosion rate and corrosion potential was also investigated. The results indicated that in the static state in simulated uterine fluid, dealuminumification of the Cu-Zn-Al alloy occurred with Cl- combining with aluminum ions to form hydroxyl aluminum chloride. The hydroxyl aluminum chloride hydrolyzed readily and facilitated further dealuminumification corrosion. The corrosion process of Cu and Cu-Zn-Al SMA in simulated uterine fluid was controlled by cathodic reduction of oxygen. Because the tendency for surface ionization is greater for aluminum than for zinc, a compact protective aluminum layer was formed, which inhibited the cathodic reduction of oxygen. Hence, the corrosion rate of Cu-Zn-Al SMA was smaller than that of Cu in simulated uterine fluid. With increasing pH, the corrosion rate of Cu and Cu-Zn-Al SMA in simulated uterine fluid decreased and the open-circuit potential moved in a positive direction.     

Association of polymorphism of tumor necrosis factor-alpha gene promoter region with outcome of hepatitis B virus infection

AIM: To determine whether -238G/A and -857C/T polymorphisms of tumor necrosis factor-alpha (TNF-α), gene promoter and hepatitis B (HB) viral genotypes were associated with outcomes of HBV infection. METHODS: A total of 244 HBV self-limited infected subjects, 208 asymptomatic carriers, and 443 chronic HB patients were recruited to conduct a case-control study. TNF-a -238G/A and -857C/T gene promoter polymorphisms were examined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), and HBV genotypes were examined by nested PCR. RESULTS: The positive rate of HBV DNA in asymptomatic carrier group and chronic HB group was 46.6% and 49.9%, respectively. HBV genotype proportion among the asymptomatic carriers was 2.1% for genotype A, 25.8% for genotype B, 68.0% for genotype C, and 4.1% for genotype B+C mixed infection, and 0.9% for genotype A, 21.7% for genotype B, 71.5% for genotype C, 5.9% for genotype B+C mixed infection in chronic HB group. There was no significant difference in genotype distribution between the asymptomatic carrier group and chronic HB group (X2 = 1.66, P = 0.647). The frequency of -238GG genotype in self-limited group was 95.1%, significantly higher than 90.7% in chronic HB group and 89.0% in asymptomatic carrier group (P= 0.041 and P= 0.016, respectively).The frequency of TNF-α-857 CC in chronic HB group was 79.7%, significantly higher than 64.4% in asymptomatic carrier group and 70.9% in self-limited group (P<0.001 and P= 0.023, respectively). A multiple logistic regression analysis revealed that TNF-α-238GA and -857CC were independently associated with chronic HB after gender and age were adjusted. CONCLUSION: TNF-α promoter variants are likely to play a substantial role in the outcome of HBV infection.     

Is there a connection between high affinity 3H-spiperone binding sites and DA-sensitive adenylate cyclase in corpus striatum ?

The possibility of a connection between the high affinity ³H-spiperone binding sites and the dopamine-sensitive adenylate cyclase system suggested by recent studies was investigated in corpus striatum. When measured under identical conditions (membrane preparation, incubation conditions, presence of dopamine), the affinity of spiperone for its binding site (1.5 × 10 ¹⁰M) was much higher than its affinity for inhibiting the dopamine sensitive adenylate cyclase (10 ⁷M). Phenoxybenzamine was found to block ³H-spiperone binding irreversibly. Phenoxybenzamine (10 ⁵M) completely supressed ³H-spiperone binding while the adenylate cyclase continued to be stimulated by dopamine (35 per cent of control stimulation) and inhibited by spiperone or haloperidol. The affinities of these neuroleptics for inhibiting the dopamine-sensitive adenylate cyclase were the same on control and phenoxybenzamine treated membranes. Consequently the ³H-spiperone binding site has not to be occupied to allow inhibition of the dopamine-sensitive adenylate cyclase. Guanosine triphosphate reduced the affinities of dopamine, 3-{2-[N-(3-hydroxyphenylethyl)N-propylamino]ethyl}phenol (RU 24926) and serotonin for ³H-spiperone binding sites and did not affect the affinity of 2-Br-α-ergocriptine. Since RU 24296 and serotonin neither stimulate nor inhibit the dopamine-sensitive adenylate eyclase, the effects of guanosine triphosphate on binding do not appear related to adenylate cyclase activation by agonists which is known to require guanosine triphosphate. Our experiments suggest that the high affnity ³H-spiperone binding sites are not related to the dopamine-sensitive adenylate cyclase.     

The use of a bedside assay for plasma B-type natriuretic peptide as a biomarker in the management of patent ductus arteriosus in premature neonates

OBJECTIVE: To test the utility of the bedside plasma concentration of B-type natriuretic peptide (BNP) assay as a screen for patent ductus arteriosus (PDA) in premature neonates. STUDY DESIGN: Newborn infants admitted to the neonatal intensive care unit (NICU) had paired echocardiography and BNP measurements at enrollment and every 4 to 5 days. RESULTS: Twenty neonates (gestational age approximately 28.6 weeks and birth weight approximately 1161 g) had 81 paired echocardiography and BNP determinations. BNP ranged from 5 to 3900 pg/mL. Fifty-six of 81 echocardiograms showed PDA. Significant correlations were found between BNP and ductal size and degree of shunting. Correlation was greater in infants >2 days of age. BNP >300 pg/mL predicted significant PDA, whereas BNP <105 pg/mL predicted absence of significant PDA. CONCLUSION: Bedside measurement of BNP correlates with magnitude of PDA in premature newborns, particularly beyond day 2, and may be useful in guiding diagnostic and management strategies.     

Nonoperative management and delayed hemorrhage after pediatric liver injury: new issues to consider

The authors report the case of a grade 4 liver laceration caused by blunt abdominal trauma. The liver injury was managed nonoperatively, both initially and after an episode of delayed hemorrhage. The patient suffered 2 additional as yet unreported complications of pediatric liver injury: a right pleural effusion causing respiratory embarrassment followed by duodenal obstruction; the latter was caused by hypertrophy of the left lobe of the liver. Although numerous reports suggest that delayed hemorrhage after pediatric liver injury should be managed operatively, the mortality of such intervention remains high, reaffirming the dictum that one must treat the patient and not the injury.