基于C型臂手术导航技术的XRⅡ图像中标志物识别及数据提取*☆

XRII图像中标志物的识别及数据提取是基于C型臂手术导航关键技术之一。现有方法可靠性差,检测精度低。本文提出一种混合标志物检测算法。首先通过一种改进CHT法获取参数空间,并获取其横切面二值化图像;而后进行连通分量分析,识别出其中的圆形体并提取其面积及中心坐标数据。改进CHT对掩模及积分算子进行了重新定义;连通分量分析则采用一种新的圆形测度。实验表明所提算法具有更高检测率、检测精度及可靠性。     

晚期前列腺癌间歇与持续性内分泌治疗的临床观察

目的:观察比较晚期前列腺癌间歇性内分泌治疗(IHT)与持续性内分泌治疗(CHT)的疗效和不良反应。方法:选取确诊的晚期前列腺癌患者共96例,之前未接受治疗,随机分为:间歇治疗组(A组)和持续治疗组(B组)。A组:54例,给予比卡鲁胺(50mg,口服,每日1次)和戈舍瑞林(3.6mg,皮下注射,每月1次)治疗,当患者血清PSA≤0.2ng/ml,暂停服用药物比卡鲁胺,当患者血清PSA>4ng/ml时,重新开始服用药物比卡鲁胺。B组:42例,同时给予比卡鲁胺和戈舍瑞林治疗,不间断治疗。终止治疗的标准是病人由激素依赖转为激素抵抗性前列腺癌。比较两组治疗前、治疗后半年、1年、2年后血清PSA、疼痛缓解及排尿梗阻症状改善情况、生活质量评分、不良反应。结果:血清PSA、疼痛缓解以及排尿梗阻改善情况上,两组治疗后各时间段较治疗前均得到显著改善(P<0.05),但两组之间无显著差异(P>0.05)。A组治疗后不良反应中去势综合征、转氨酶升高、贫血以及乳房发育发生率较B组显著降低(P<0.05),生活质量评分明显升高(P<0.05)。结论:IHT和CHT对晚期前列腺癌治疗效果无明显差异,都能缓解患者的症状和提高患者的生活质量,但IHT不良反应发生率较持续治疗显著降低,生活质量明显提高,值得临床椎广。     

Peripheral type of choline acetyltransferase: biological and evolutionary implications for novel mechanisms in cholinergic system

The peripheral type of choline acetyltransferase (pChAT) is an isoform of the well-studied common type of choline acetyltransferase (cChAT), the synthesizing enzyme of acetylcholine. Since pChAT arises by exons skipping, its amino acid sequence is similar to that of cChAT, except the lack of a continuous peptide sequence encoded by all the four exons from 6 to 9. While cChAT expression has been observed in both the central and peripheral nervous systems, pChAT is preferentially expressed in the peripheral nervous system.pChAT appears to be a reliable marker for the visualization of peripheral cholinergic neurons and their processes, whereas other conventional markers including cChAT have not been used successfully for it. In mammals like rodents, pChAT immunoreactivity has been observed in most, if not all, physiologically identified peripheral cholinergic structures such as all parasympathetic postganglionic neurons and most neurons of the enteric nervous system. In addition, pChAT has been found in many peripheral neurons that are derived from the neural crest. These include sensory neurons of the trigeminal ganglion and the dorsal root ganglion, and sympathetic postganglionic neurons. Recent studies moreover indicate that pChAT, as well as cChAT, appears ubiquitously expressed among various species not only of vertebrate mammals but also of invertebrate mollusks. This finding implies that the alternative splicing mechanism to generate pChAT and cChAT has been preserved during evolution, probably for some functional benefits.     

基于C型臂手术导航技术的XRⅡ图像中标志物识别及数据提取

XRⅡ图像中标志物的识别及数据提取是基于C型臂手术导航关键技术之一.现有方法可靠性差,检测精度低.文章提出一种混合标志物检测算法,首先通过一种改进CHT法获取参数空间,并获取其横切面二值化图像:而后进行连通分量分析,识别出其中的圆形体并提取其面积及中心坐标数据.改进CHT对掩模及积分算子进行了重新定义;连通分量分析则采用一种新的圆形测度.实验结果表明,所提算法具有更高检测率、检测精度及可靠性.     

Women’s Experiences of Food Insecurity and Coping Strategies in the Chittagong Hill Tracts,Bangladesh

Despite advances in food production and distribution technologies, global food insecurity continues throughout parts of South Asia. Using ethnographic data collected from the Chittagong Hill Tracts (CHT) in Bangladesh, this article reports on gendered and ethnocultural variations in experiences of food insecurity. Three key findings are that (1) regardless of ethnicity, the majority of the households in this study suffered moderate food insecurity; (2) food insecurity was higher among female-headed households; and (3) women’s means of coping strategies varied depending on household structure and ethnic identity. It is argued that indigenous women’s coping strategies were protective in comparison with Bengali women’s experiences.     

Inhibition of choline uptake by N-cyclohexylcholine,a high affinity ligand for the choline transporter at the blood–brain barrier

The blood–brain barrier (BBB) choline transporter (CHT) may have utility as a drug delivery vector for drugs that act in the central nervous system. Previous studies suggested the importance of hydrophobic moieties on the cationic nitrogen of choline for improved affinity for this transporter. In a pilot study, we therefore designed five novel N-cycloalkyl derivatives of choline, one of which showed promising inhibition properties. This choline analogue had a cyclohexyl (UMBB-5) moiety substituting one of the methyl groups attached to the cationic nitrogen in choline. In situ experimental data were obtained from in situ rat brain perfusion studies. The binding affinity for the BBB-choline transporter found for UMBB-5 was K_i = 1.9 µM. Comparative molecular field analysis (CoMFA) suggested that the cyclohexyl moiety orientates towards a steric favourable area. Taken together, the results of these in situ and in silico studies provide further evidence or restrictions that occur with binding to this brain drug delivery vector.     

Narcoleptic orexin receptor knockout mice express enhanced cholinergic properties in laterodorsal tegmental neurons

Pharmacological studies of narcoleptic canines indicate that exaggerated pontine cholinergic transmission promotes cataplexy. As disruption of orexin (hypocretin) signaling is a primary defect in narcolepsy with cataplexy, we investigated whether markers of cholinergic synaptic transmission might be altered in mice constitutively lacking orexin receptors (double receptor knockout; DKO). mRNA for Choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT) and the high‐affinity choline transporter (CHT1) but not acetylcholinesterase (AChE) was significantly higher in samples from DKO than wild‐type (WT) mice. This was region‐specific; levels were elevated in samples from the laterodorsal tegmental nucleus (LDT) and the fifth motor nucleus (Mo5) but not in whole brainstem samples. Consistent with region‐specific changes, we were unable to detect significant differences in Western blots for ChAT and CHT1 in isolates from brainstem, thalamus and cortex or in ChAT enzymatic activity in the pons. However, using ChAT immunocytochemistry, we found that while the number of cholinergic neurons in the LDT and Mo5 were not different, the intensity of somatic ChAT immunostaining was significantly greater in the LDT, but not Mo5, from DKO than from WT mice. We also found that ChAT activity was significantly reduced in cortical samples from DKO compared with WT mice. Collectively, these findings suggest that the orexins can regulate neurotransmitter expression and that the constitutive absence of orexin signaling results in an up‐regulation of the machinery necessary for cholinergic neurotransmission in a mesopontine population of neurons that have been associated with both normal rapid eye movement sleep and cataplexy.     

Cloning and molecular characterization of the orphan carrier protein Slc10a4: expression in cholinergic neurons of the rat central nervous system

We report on the cloning and molecular characterization of the rat carrier Slc10a4 and its cellular localization in the CNS by immunohistochemistry. Slc10a4 is the rat counterpart of the human orphan carrier SLC10A4, which was recently reported to be highly expressed in brain and placenta. Both carriers belong to the solute carrier family SLC10, formerly named the "sodium/bile acid cotransporter family." So SLC10A4/Slc10a4 has a phylogenetic relationship to the Na+/taurocholate cotransporting polypeptide Ntcp (Slc10a1) and the apical sodium-dependent bile acid transporter Asbt (Slc10a2). The rat Slc10a4 protein consists of 437 amino acids and exhibits a seven transmembrane domain topology with N(exo)/C(cyt)trans-orientation of the N- and C-terminal ends. Expression of the Slc10a4 protein was detected in motor regions of the spinal cord and rhombencephalon, as well as in mesopontine cholinergic neurons, the medial habenula, cholinergic areas of the forebrain, and the gut myenteric plexus. Co-localization studies with the cholinergic marker proteins choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT), and high-affinity choline transporter (CHT1) demonstrated expression of Slc10a4 in cholinergic neurons. Despite its close phylogenetic relationship to Ntcp, Slc10a4 showed no transport activity for the Ntcp substrates taurocholate, estrone-3-sulfate, dehydroepiandrosterone sulfate, and pregnenolone sulfate when expressed in HEK293 cells or Xenopus laevis oocytes. Slc10a4 also did not transport choline, which is a substrate of CHT1. Although the functional properties of Slc10a4 could not be elucidated in this study, Slc10a4 is regarded as a new marker protein for cholinergic neurons in the rat CNS.     

Krill phosphatidylserine improves learning and memory in Morris water maze in aged rats

The ameliorating effect of phosphatidylserine (PS) isolated from krill (KR-PS) on the learning and memory deficits associated with normal aging in rats was investigated, as compared with soybean PS (SOY-PS). Rats were orally administered with KR-PS (20, 50 mg kg⁻¹) and SOY-PS (50 mg kg⁻¹) daily, for 7 days, 30 min before behavioral assessment using the Morris water maze (MWM). Changes in the cholinergic system were examined by measuring choline acetyltransferase (ChAT) and acetylcholinesterase (AchE) immunoreactivity in the hippocampus. The daily administration of KR-PS produced a significant improvement in the escape latency for finding the platform in the MWM, as compared with SOY-PS. Consistent with the behavioral results, KR-PS treatments significantly alleviated age-associated losses of cholinergic immunoreactivity, and muscarinic acetylcholine receptor type 1 (mAChR-M1) and choline transporter (CHT) mRNA expression in the hippocampus. These findings demonstrate that KR-PS showed significant neuroprotective activity against the neuronal and cognitive impairments that occur with normal aging in rats; comparable results were obtained with SOY-PS. These data indicate that oral administration of PS derived from marine life could substitute for bovine cerebral cortex PS (BC-PS) as therapy for the improvement of diminished memory function in elderly people.     

The effect of prenatal nicotine on mRNA of central cholinergic markers and hematological parameters in rat fetuses

A number of studies have demonstrated the influence of nicotine on fetal development. This study determined the expression of choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT), and high-affinity choline transporter (CHT1) in the forebrain and hindbrain following chronic prenatal nicotine exposure in the rat fetus (maternal rats were subcutaneously injected with nicotine at different gestation periods). We also measured the effect of chronic nicotine exposure on fetal blood pO₂, pCO₂, pH, Na⁺ and K⁺ concentrations, as well as lactic acid levels. Maternal nicotine exposure during pregnancy was associated with a decrease in fetal pO₂ coupled with a significant increase in pCO₂ and lactic acid as well as restricted fetal growth. Additionally, maternal nicotine administration also reduced ChAT, VAChT, and CHT1 mRNA levels in the fetal brain. Nicotine-induced fetal hypoxic responses and reduced cholinergic marker expression in the brain were more severe when nicotine was started in early gestation. Our results provide new information about the effects of repeated exposure to nicotine in utero on the expression of central ChAT, VAChT, and CHT1 in the rat fetus. These results indicate that repeated hypoxic episodes or/and a direct effect of nicotine on the central cholinergic system during pregnancy may contribute to brain developmental problems in fetal origin.