Expression of early gene proteins,structural changes in brain neurons in hypobaric hypoxia,and the correcting effects of preconditioning

The Nissl method and immunocytochemistry were used to study the effects of severe hypobaric hypoxia and its actions in combination with the preconditioning actions of moderate hypoxia on the expression of the early gene proteins c-Fos and NGFI-A as well as structural changes in hippocampal and neocortical neurons in the rat brain. Severe hypoxia was found to suppress c-Fos and NGFI-A synthesis (3–24 h after exposure) and to induce delayed (days 3–7) structural damage to neurons, of the light and predominantly the dark types, which appear to reflect the development of necrotic and apoptotic processes respectively. Preconditioning with the regime used here corrected these derangements, resulting in increases in the expression of early gene proteins and significant reductions in structural damage to neurons after severe hypoxia.Translated from Morfologiya, Vol. 125, No. 2, pp. 10–15, March–April, 2004.     

A Novel Method of Evaluating the Impact of Secondary Brain Insults on Functional Outcomes in Traumatic Brain-injured Patients

OBJECTIVES: Prior studies suggest that the emergency department (ED) occurrence of secondary brain insults (SBIs), such as systemic hypotension and hypoxia, worsens outcome in patients with traumatic brain injury. However, previous methods of assessing SBIs have been relatively crude, generally only determining the incidence and duration of events. The authors hypothesized that a new method that accounts for the cumulative depth and duration of SBIs would provide a more informative measure that better correlates with outcome. METHODS: The authors developed a computer algorithm to calculate the total "dose" of an SBI (in this case, hypotension and hypoxia) as the area under the curve between a cut-point value and a measured vital sign over time. To test this method, the authors used an existing data set of head trauma patients for whom occurrence in the ED of any hypotension had been shown to be associated with in-hospital mortality. The authors applied the algorithm using the cut-point values from the prior study (systolic blood pressure hypoxia (dose range 0.005-6.7% . min). Moderate and high doses of hypotension were more strongly associated with outcome than the measures from the initial study (any hypotension and number of hypotensive episodes). Hypoxia had no effect. CONCLUSIONS: New methods of measuring SBIs that take into account depth and duration of episodes may more accurately reflect the influence of these events on outcome after head trauma.     

葛根素对小儿重症肺炎心肌保护作用的研究

目的 探讨葛根素对小儿重症肺炎心肌保护作用。方法 选择婴幼儿肺炎100例,根据病情分为重症组52例、轻症组48例,治疗前后测心肌酶谱、心电图及心脏血流参数。重症组在常规治疗基础上分别进行了葛根素和二磷酸果糖(FDP)心肌保护治疗的比较观察。结果 肺炎患儿心肌酶的改变,与病情程度成正比;超声多普勒检查反映心脏血流参数的改变,证明心脏收缩功能下降(P<0．01)。葛根素和FDP均具有保护心肌损伤、改善心功能的作用,两者比较差异无显著性(P>0．05),而葛根素注射液较FDP血管刺激性小,未见明显不良反应发生。结论 (1)小儿重症肺炎可以导致心肌损伤和心力衰竭,早期心肌保护治疗能明显改善预后;(2)心肌酶学检查是心肌损伤敏感而重要的测定指标,其中肌酸激酶同功酶(CK—MB)最敏感。(3)葛根素注射液具有保护心肌、改善心功能的作用,适宜临床推广应用。     

Assessment of regional tumor hypoxia using F-fluoromisonidazole and Cu(II)-diacetyl-bis(N4-methylthiosemicarbazone) positron emission tomography: Comparative study featuring microPET imaging, Po2 probe measurement, autoradiography, and fluorescent microscopy in the R3327-AT and FaDu rat tumor models

PURPOSE: To compare two potential positron emission tomography (PET) tracers of tumor hypoxia in an animal model. METHODS AND MATERIALS: The purported hypoxia imaging agents (18)F-fluoromisonidazole (FMISO) and (64)Cu(II)-diacetyl-bis(N4-methylthiosemicarbazone) (Cu-ATSM) were compared by serial microPET imaging of Fisher-Copenhagen rats bearing the R3327-AT anaplastic rat prostate tumor. Probe measurements of intratumoral Po(2) were compared with the image data. At the microscopic level, the relationship between the spatial distributions of (64)Cu (assessed by digital autoradiography) and tumor hypoxia (assessed by immunofluorescent detection of pimonidazole) was examined. (18)F-FMISO and (64)Cu-ATSM microPET images were also acquired in nude rats bearing xenografts derived from the human squamous cell carcinoma cell line, FaDu. RESULTS: In R3327-AT tumors, the intratumoral distribution of (18)F-FMISO remained relatively constant 1-4 h after injection. However, that of (64)Cu-ATSM displayed a significant temporal evolution for 0.5-20 h after injection in most tumors. In general, only when (64)Cu-ATSM was imaged at later times (16-20 h after injection) did it correspond to the distribution of (18)F-FMISO. Oxygen probe measurements were broadly consistent with (18)F-FMISO and late (64)Cu-ATSM images but not with early (64)Cu-ATSM images. At the microscopic level, a negative correlation was found between tumor hypoxia and (64)Cu distribution when assessed at early times and a positive correlation when assessed at later times. For the FaDu tumor model, the early and late (64)Cu-ATSM microPET images were similar and were in general concordance with the (18)F-FMISO scans. CONCLUSION: The difference in behavior between the R3327-AT and FaDu tumor models suggests a tumor-specific dependence of Cu-ATSM uptake and retention under hypoxic conditions.     

Cardiovascular alterations by chronic intermittent hypoxia: importance of carotid body chemoreflexes

1. Humans experiencing intermittent hypoxia (IH) owing to recurrent apnoea syndromes exhibit serious cardiovascular morbidity, including high blood pressure, increased sympathetic nerve activity, cardiac arrhythmia and myocardial infarction. Although apnoeas are accompanied by a simultaneous decrease in arterial O(2) (hypoxia) and an increase in CO(2) (hypercapnia), studies on experimental animals suggest that hypoxia, rather than hypercapnia, is the primary stimulus for developing hypertension and enhanced sympathetic nerve activity. Enhanced hypoxic-sensing ability of the carotid bodies and the ensuing reflex activation of the sympathetic nervous system have been suggested to play a critical role in cardiorespiratory alterations resulting from recurrent apnoeas. 2. The purpose of the present review is to highlight recent studies demonstrating the effects of IH on carotid body sensory activity and its consequences on sympathetic activation in a rodent model of chronic IH. Adult rats exposed to chronic IH (15 s of 5% O(2) followed by 5 min of 21% O(2), nine episodes per h, 8 h/day for 10 days) exhibited selective enhancement of carotid body sensory response to hypoxia. In addition, chronic IH induced a novel form of sensory plasticity in the carotid body, manifested as sensory long-term facilitation (LTF). Functional changes in the carotid body occurred in the absence of morphological changes in the chemoreceptor tissue. 3. Acute hypoxia increased expiratory modulated splanchnic nerve activity (SNA) and acute IH-induced LTF in SNA. Hypoxia-induced SNA activation was prevented by bilateral sectioning of the sinus nerves. Rats exposed to chronic IH exhibited enhanced hypoxia-induced sympathetic activation and augmented LTF of the SNA. Bilateral sectioning of the sinus nerves abolished these responses, suggesting chronic IH-induced alterations in carotid body sensitivity contribute to LTF in SNA and the subsequent cardiovascular alterations.     

Exogenous nitric oxide centrally enhances pulmonary reactivity in the normal and hypertensive rat

1. Chronic hypoxia causes sustained pulmonary hypertension and, although impairment of the pulmonary endothelial nitric oxide (NO) pathway has been implicated, no study has described the central role of NO in modulating pulmonary vascular tone and reactivity. Centrally, NO inhibits sympathetic outflow, so we hypothesised that central NO would modulate pulmonary vascular tone and its reactivity to acute hypoxia, especially in the hypertensive state. 2. Male adult Sprague-Dawley rats were exposed to normoxia (N) or chronic hypoxia (CH; 12% O2) for 14 days. Mean pulmonary arterial pressure (MPAP), systemic mean arterial blood pressure (MABP), cardiac output and heart rate were then measured in pentobarbitone-anaesthetized, artificially ventilated rats. The N and CH rats were exposed to acute hypoxia (10% O2 for 4 min) after the intracerebroventricular (i.c.v.) administration of artificial cerebrospinal fluid (control) and then again after either i.c.v. NG-nitro-L-arginine methyl ester (L-NAME; 150 microg in 10 microL) or 3-morpholino-sydnonimine hydrochloride (SIN-1; 100 microg in 10 microL). 3. Chronic hypoxia caused pulmonary hypertension (MPAP 20+/-1 vs 30+/-1 mmHg in N and CH rats, respectively) and attenuated acute hypoxic pulmonary vasoconstriction (HPV). Central inhibition of NO synthesis (by l-NAME) did not alter baseline MPAP or the acute HPV in either N or CH rats, but it did elevate MABP. The NO donor SIN-1 did not alter baseline MPAP, but it did enhance (N rats) or restore (CH rats) the HPV and decreased MABP. 4. The results of the present study indicate that central NO has a limited role in the tonic modulation of MPAP during normoxia and after chronic hypoxia. However, the acute HPV seems to be enhanced by exogenous NO.     

用45MV轫致辐射在肿瘤组织产生的光核反应和PET显像研究肿瘤的乏氧情况

目的:提出了一种新的肿瘤乏氧研究方法——光核反应PET显像法,并用放置在同一房间的LA45加速器和PET实验研究该方法。材料与方法:"光核反应PET显像法"研究肿瘤乏氧的原理是由于血液中80%的成分为氧(16O),利用高能光子(如45 MV)辐照人体肿瘤诱发的光核反应16O(γ,n)15O产生的15O的PET显像位置和活度分布,分析确定肿瘤靶区内氧(16O)的分布和肿瘤的血流灌注信息,继而推测肿瘤内部的乏氧(16O)情况和位置分布。选择腹部肿瘤、肝癌、肺癌和肾癌患者5人,肿瘤大小范围从10 cm×10 cm～1.2 cm×1.0 cm,按常规的3DCRT规范对肿瘤部位实施均匀剂量的照射治疗,其中在第一分次治疗时,用LA45加速器45 MV X射线按TPS方案行3野～5野2 Gy～3 Gy剂量照射,随后立即将患者快速转移(大约2 min)至同一治疗室的PET进行20 min的15O扫描显像,对扫描结果进行必要的衰减校正等分析处理,获得15O的在照射位置的活度分布,进而确定肿瘤部位氧(16O)的分布,通过与治疗计划TPS的结果比较,便可推知肿瘤内部的乏氧情况和照射位置是否准确等。结果和讨论:对较大的实体肿瘤,该方法能很好分析出肿瘤内是否存在乏氧。这可能是因为较大实体的肿瘤内容易形成乏氧区,生成的15O活度密度分布差容易区分。对肿瘤病灶小(CTV小于2 cm)且处于密度相对低的组织如肺,15O不能形成有效显像。这可能由于肿瘤很小,且在组织密度低的、毛细血管发达的肺部,这样不仅生成的15O活度密度(单位体积的15O活度)相对较少,而且生成的15O也可能很容易由发达的毛细血管冲洗到肿瘤外部并被稀释。由于15O半衰期很短,为了减少时间,一般设计3野2 Gy照射计划,这样适形度稍差些,更不利的是容易在皮肤表面形成较强的显像,如果单次剂量能给到3 Gy,可以设计5个野,这样既能有清晰的显像,又有较好的适形度,更重要的是不会在皮肤表面产生很强的干扰显像。     

HIF-1α因子在在子宫内膜癌中的表达及其临床意义

目的检测HIF-1α（缺氧诱导因子-1α）因子蛋白在子宫内膜癌组织中的表达及其临床意义。方法 1.采用免疫组织化学染色的方法,检测72例子宫内膜癌组织标本中HIF-1α蛋白的表达;2.采用胶体金标记免疫电镜的方法,检测子宫内膜癌组织中HIF-1α蛋白在超微结构中的表达。结果 1.免疫组织化学染色结果显示：在收集的72例临床子宫内膜癌组织标本中,39例HIF-1α表达为阳性,阳性率为54.2%（39/72）;2.胶体金标记免疫电镜结果显示：黑色圆形的HIF-1α胶体金颗粒存在于内膜癌细胞的内质网和核膜上,偶见核内。结论免疫组化和免疫电镜显示：子宫内膜癌组织中存在HIF-1α的表达,提示HIF-1α可作为子宫内膜癌治疗的新的分子靶点。     

低氧对食管癌Eca109细胞体外迁移及侵袭的影响

 目的 探讨低氧对食管癌迁移及侵袭能力的影响及其作用机制。方法 采用CoCl2化学低氧法模拟肿瘤低氧微环境,半定量RT-PCR和免疫细胞化学分别检测不同低氧时相时食管癌Eca109细胞中低氧诱导因子-1α（HIF-1α）、E-钙粘蛋白及基质金属蛋白酶-2（MMP-2）mRNA及蛋白的表达。Western印迹法检测雷帕霉素联合低氧处理Eca109细胞后,HIF-1α、E-钙粘蛋白及MMP-2的变化。细胞划痕试验和Transwell实验检测雷帕霉素联合低氧对Eca109细胞迁移及侵袭能力的影响。结果 Eca109细胞在低氧状态下,HIF-1αmRNA无明显变化（P>0.05）,仅蛋白表达增多;E-钙粘蛋白的mRNA表达明显降低（P<0.05）,蛋白表达减少;MMP-2 mRNA表达明显升高（P<0.05）,蛋白表达增多。雷帕霉素在低氧状态下可显著抑制HIF-1α及MMP-2表达,促进E-钙粘蛋白高表达。经雷帕霉素处理后,Eca109细胞在低氧状态下,迁移速度减慢,侵袭穿膜细胞数减少（P<0.05）。结论 低氧使Eca109细胞中HIF-1α蛋白表达增多,后者可能通过下调E-钙粘蛋白、上调MMP-2表达促进食管癌在低氧状态下的迁移及侵袭。