C-fos gene expression in rat brain around birth: effect of asphyxia and catecholamines

At birth, the mammalian nervous system must adapt rapidly to the new conditions it encounters in the extra-uterine environment. One aspect of this adaptation, known as arousal, is mediated by catecholamines, the levels of which in the brain increase rapidly after birth. The pattern of gene expression also changes. Shortly after birth, expression of the immediate early gene c-fos, known to reflect general neural activity, is up-regulated. Furthermore, asphyxia often occurs in connection with birth. In order to examine the effects of this phenomenon on the expression of c-fos, as well as on the rate of noradrenaline (NA) turnover, asphyxia was induced in rat pups delivered by caesarean section. Northern blot analysis and in situ hybridization revealed that the increase in expression of c-fos in certain areas of the brain was greatly enhanced by asphyxia of moderate duration; whereas more prolonged asphyxia lowered the level of c-fos mRNA. Asphyxia had a similar effect on the rate of NA turnover. Adrenergic receptor antagonists administered prior to birth attenuated the birth-related induction of c-fos mRNA. However, the potentiation of c-fos expression by asphyxia was not altered by these antagonists. Therefore, we propose that while catecholamines play an important role in the induction of c-fos in the brain at birth, the effects of asphyxia involve a different mechanism.     

Striatal trophic activity is reduced in the aged rat brain

Our previous studies demonstrated that the survival of a mesencephalic graft was reduced in aged animals suggesting an age-related decline in target-derived neurotrophic activity. We tested this hypothesis by examining dopamine (DA) and trophic activities from the striatum of intact or unilateral 6-hydroxydopamine (6-OHDA) lesioned rats of increasing age. Fisher 344 rats were 4, 12, 18, and 23 months old (m.o.) at sacrifice. Half the animals had received unilateral 6-OHDA lesions of the mesostriatal DA pathway 8 weeks earlier. Striatal tissue punches were analyzed for DA, homovanillic acid (HVA), and DA activity (HVA/DA) using HPLC. The remainder of the striatal tissue was homogenized to generate tissue extracts which were added to E14.5 ventral mesencephalic cultures to test trophic activity. In the non-lesioned animals, striatal DA was reduced and striatal DA activity was increased in the 18 and 23 m.o. animals relative to the 4 and 12 m.o. animals. Striatal trophic activity was inversely related to age. In the lesioned animals, striatal DA ipsilateral to 6-OHDA infusion was below detection limits while the contralateral striatum exhibited age-related changes in DA similar to those seen in the non-lesioned animals. In 4 m.o. lesioned rats, striatal trophic activity ipsilateral to 6-OHDA infusion was elevated by 26% relative to the contralateral side. The ipsi/contra-lateral differences in striatal trophic activity were reduced in 12 m.o. animals and absent in the 18 and 23 m.o. groups. These data suggest that advancing age is associated with a reduction in striatal DA as well as trophic activity. Moreover, the aged striatum loses its ability to biochemically and trophically compensate for DA reduction and therefore may represent a more challenging environment for the survival, growth, and function of a fetal graft.     

R(+)-8-OH-DPAT, a selective 5-HT(1A) receptor agonist, attenuated amphetamine-induced dopamine synthesis in rat striatum, but not nucleus accumbens or medial prefrontal cortex

R(+)-8-OH-DPAT (0.05, but not 0.025, 0.1, 1 mg/kg), a 5-HT(1A) receptor agonist, decreased l-3,4-dihydroxyphenylalanine (DOPA) accumulation in rat striatum following NSD-1015, an l-aromatic amino acid decarboxylase inhibitor. Amphetamine (1 mg/kg) increased striatal DOPA accumulation, an effect attenuated by R(+)-8-OH-DPAT (0.05 mg/kg). However, both amphetamine (1 mg/kg) and R(+)-8-OH-DPAT (0.05 mg/kg) decreased cortical DOPA accumulation; there were no additional decreases from their combination. Neither amphetamine (1 mg/kg), R(+)-8-OH-DPAT (0.05 mg/kg), or the combination, significantly affected DOPA accumulation in the nucleus accumbens. The significance of and possible mechanisms for these findings are discussed.     

Localization of thyroid hormone receptor beta2 in the ventral medullary neurons that synthesize thyrotropin-releasing hormone

Altered thyroid statuses are associated with autonomic disorders. Thyrotropin-releasing hormone (TRH) synthesized in medullary raphe pallidus (Rpa), raphe obscurus (Rob) and the parapyramidal regions (PPR) regulates vagal and sympathetic preganglionic motoneurons. Hypothyroidism increased TRH gene expression and c-Fos immunoreactivity (IR) in these nuclei. Whether these increases represent a direct action of thyroid hormone was studied by detecting the presence of thyroid hormone receptor beta2 (TRbeta2) in pro-TRH-synthesizing neurons in the Rpa, Rob and the PPR using immunohistochemistry with specific TRbeta2 antiserum and in situ hybridization with digoxigenin-labeled pro-TRH cRNA probe. TRbeta2 IR was widely distributed throughout the medulla and primarily localized within the cell nuclei. Particularly intense immunostaining was presented in the Rpa, Rob and the PPR neurons. The combination of immunohistochemistry with in situ hybridization revealed that all pro-TRH mRNA-positive neurons in these ventral medullary nuclei were also TRbeta2 IR positive. The numbers of TRbeta2 IR-positive neurons in each nucleus were identical in both euthyroid rats and hypothyroid rats induced by 6-n-propyl-2-thiouracil in drinking water for 4 weeks. The finding that TRbeta2 localized in pro-TRH-synthesizing neurons in the ventral medullary nuclei provides an anatomical substrate for a direct thyroid hormone action on these neurons in the regulation of TRH gene expression, which may contribute to the altered autonomic activity in different thyroid statuses.     

Long-term survival following emergency abdominal aortic aneurysm repair

Survival following emergency surgery for ruptured abdominal aortic aneurysm remains poor and is in stark contrast to that for elective repair. We have carried out a 5-year retrospective observational study to determine the long-term (5-year) survival of patients following emergency surgery for ruptured abdominal aortic aneurysm at a district general hospital in East Anglia. A total of 99 patients presented to the operating theatre for emergency repair of ruptured abdominal aortic aneurysm in this 5-year study period. In-hospital mortality was 70% and was unchanged over the 5 years. Overall long-term survival in those patients discharged from hospital was good. The ICU cost per long-term survivor was calculated to be pound sterling 36750.     

Takayasu's arteritis

This paper reviews the literature of Takayasu's arteritis (T.A.). The concept of this disease has evolved considerably over the past decades. T.A. was first described by Mikito Takayasu in 1908, and was thought to be restricted to south-east Asia. But due to the increasing reports from all over the world, it is well established that T.A. has world-wide distribution. Clinical presentation varies according to the location of the arterial lesions. In Europe brachiocephalic trunk lesions prevail and are best managed by an arterial reconstruction. Historical background, epidemiology, etiology, pathology, clinical findings, diagnosis, classification, treatment and long-term prognosis are discussed.     

Dynamic progression of contractile and endothelial dysfunction and infarct extension in the late phase of reperfusion

BACKGROUND: Myocardial injury during early reperfusion (R) has been well documented. However, the extent and time course of myocardial injury during late R are still unclear. The purpose of this study was to determine the extent of regional contractile and endothelial dysfunction and myocardial blood flow (MBF) defect as well as extension of infarction in association with neutrophil (PMN) actions during R. MATERIALS AND METHODS: A total of 29 dogs underwent a protocol of 1 h LAD ischemia followed by 6, 24, 48, and 72 h of R, respectively. Regional contractile function (sonomicrometry), MBF (colored microspheres), infarct size (triphenyltetrazolium chloride staining), and PMN localization (immunohistochemistry) were determined. RESULTS: Percentage segmental shortening at 6, 24, 48, and 72 h of R was significantly blunted (-1.8 +/- 1.2,* - 0.37 +/- 0. 6,* 0.04 +/- 0.2,* and 5.9 +/- 1.2* vs baseline 17.7 +/- 0.8). MBF (ml/min/g) was attenuated at 24 (0.27 +/- 0.03*), 48 (0.46 +/- 0. 07*), and 72 h of R (0.48 +/- 0.06*) vs 6 h of R (0.65 +/- 0.06). Infarct size increased from 6 (27 +/- 2%) to 24 h of R (41 +/- 2%*) with no further increase at 48 and 72 h of R, consistent with a peak of creatine kinase activity. PMN adherence (mm(2) endothelium) to left anterior descending coronary artery (LAD) segments was increased after 6 h of R (63 +/- 3*) vs nonischemic left circumflex coronary artery (LCX) segments (42 +/- 2) with a peak at 48 h of R (111 +/- 5*). Endothelium-dependent vascular relaxation in the LAD was also blunted at 6, 24, and 48 h of R. Immunostaining revealed CD18-positive PMNs were mainly accumulated in intravascular space during 6 h of R with an increase in migration of PMNs seen at 24 h of R, consistent with a peak of myeloperoxidase release. Myeloperoxidase activity in a given area at risk sample was significantly correlated with infarct extension during the first 24 h of R. CONCLUSIONS: These results provide pathologic evidence for myocardial injury during the extended R and a basis for exploration of interventions designed to limit myocardial injury after ischemia. (*P < 0.05 vs Baseline, 6 h of R and LCX segments.) Copyright 2000 Academic Press.     

人工耳蜗植入术后植入电极的影像学检查

目的 探讨建立螺旋CT扫描及三维重建技术观察人工耳蜗植入电极方法，并比较X线摄片方法与螺旋CT扫描三维重建方法的耳蜗内电极的影像学特征及其临床应用价值。方法 18例人工耳蜗植入患者全部作术后X线摄片检查。其中9例用经眼眶前后位摄片，9例采用侧斜位60。摄片。3例患者施行术后螺旋CT扫描及内耳三维重建方法。结果 2种投射头位的X线摄片均可显示电极形态及单个电极对，可间接判断电极在耳蜗内的植入深度。螺旋CT扫描三维重建图可直观地显示耳蜗形态、电极形态及其在耳蜗内植入的深度，可清晰识别单个电极对。结论 螺旋CT扫描三维重建方法可直观观察植入电极的形态及位置，可准确判断电极在耳蜗内植入的深度，有其独特的临床应用价值。     

穿透性角膜移植术治疗坏死性基质角膜炎23例

目的:探讨穿透性角膜移植术(penetratingkeratoplasty,PKP)治疗坏死性基质角膜炎(necrotizingstromalkeratitis)的手术适应证及其临床效果。方法:按照Holland等的HSK新分类法,选择确诊坏死性基质角膜炎患者,予以局部及全身药物治疗。对病情不能控制,药物治疗无效的患者22例(23眼),其中角膜溶解穿孔3眼,用新鲜角膜组织行穿透性角膜移植术,并随访观察术后疗效。结果:随访3mo～3a,22例(23眼)中,术后视力提高者18眼,其中矫正视力达到0.1～0.5者12眼,0.05～0.1者6眼;无改善者5眼。角膜植片透明17眼,半透明2眼,植片混浊4眼,植片透明率为74%。术后3眼植片发生排斥反应,3眼原发病灶复发。2眼术后因排斥反应及原发病灶反复发作,植片完全混浊,行2次角膜移植术。结论:对坏死性基质角膜炎患者,药物保守治疗无效、角膜坏死穿孔或行将穿孔,及时用新鲜角膜组织行穿透性角膜移植术治疗,不仅能控制炎症,缩短病程,而且能保存眼球,恢复部分视力,因此具有重要临床应用价值。