Acetylcholinesterase in the ventrobasal thalamus: transience and patterning during ontogenesis

In this study, maturational alterations in acetylcholinesterase-dependent staining of the thalamic ventrobasal complex of rat and mouse were examined. The study was undertaken to address the question of whether this nucleus exhibits transient acetylcholinesterase positivity during its development and whether the enzyme is likely to be synthesized by its immature intrinsic neurons. Also, the patterning due to acetylcholinesterase staining of cells and fibers, and the developmental changes in these patterns, have not been described in earlier work. In contrast to surrounding thalamic nuclei, the ventrobasal complex is acetylcholinesterase-positive at birth. In rat, acetylcholinesterase staining of the ventrobasal thalamus is still more intense than in adjacent nuclei at the end of the first week postnatally. Virtually all somata in the nucleus are filled with dense reaction product at this time. Ultrastructurally, reaction product is associated with the granular endoplasmic reticulum. At this stage, there is a marked difference in intensity of staining between the medial and lateral subdivisions of the nucleus, and patterned clustering of somata within each subdivision is readily appreciated in acetylcholinesterase-stained material. In the second postnatal week, intrinsic acetylcholinesterase activity is progressively lost. By the end of the third postnatal week, the nucleus is quite pale except for one area. In the posterior portion of the lateral subdivision, adjacent to the nucleus reticularis, interconnecting bundles of acetylcholinesterase-positive fibers enter the nucleus. They course medially in the lateral subdivision and break up into a plexus of fine fibers. The development of acetylcholinesterase-dependent staining patterns in the mouse is quite similar, except that histochemically detectable levels of enzyme are substantially lower in the neonatal period. It is concluded that the ventrobasal complex can be distinguished from other thalamic nuclei in regard to earlier onset and/or transience of acetylcholinesterase staining. Ultrastructural observations suggest that virtually all immature ventrobasal neurons are synthesizing acetylcholinesterase. It is suggested that the transient staining for enzyme is due primarily to alteration in synthesis and/or turnover in neurons of the ventrobasal complex. In addition, the acetylcholinesterase staining reveals a patterning of fibers and cells that also undergoes developmental alteration. Evidence is discussed suggesting that axons in the barrels of somatosensory cortex (SmI) are derived from these transiently acetylcholinesterase-positive somata. Consequently, the loss of acetylcholinesterase fiber staining in the barrels, during the third postnatal week (noted previously), may be related to a decrease in synthesis of enzyme in the neuronal somata of the ventrobasal complex.     

Tolfenamic acid and caffeine: A useful combination in migraine

Tolfenamic acid is a potent inhibitor of prostaglandin biosynthesis, which has been proved effective in the treatment of acute migraine attacks. The usefulness of caffeine, metoclopramide and pyridoxine as adjuncts to tolfenamic acid was tested in acute migraine attacks in ten patients. A combination of tolfenamic acid (200 mg) with either caffeine (100 mg), metoclopramide (10 mg) or pyridoxine (300 mg) was given twice to each patient in random order. Thus 60 attacks were treated. The tolfenamic acid-caffeine combination proved the most effective as judged by duration and intensity of attacks, working ability, vigilance, and overall evaluation of the drugs by the patients. Metoclopramide was somewhat better than pyridoxine as an additive.     

Effect of vitamin B6 administration on elevated plasma oxalic acid levels in haemodialysed patients

Abstract. Accumulation of oxalic acid resulting in elevated plasma levels is a common finding in uraemic patients. Since vitamin B₆ is an important coenzyme in oxalic acid metabolism the influence of vitamin B₆ administration on plasma oxalic acid levels was investigated.
Vitamin B₆ was administered to eight chronic haemodialysis patients with secondary hyperoxalaemia. Mean plasma oxalic acid concentration decreased from 149·5 ± 67 μmol/l to 99·0 ± 36·4 μmol/l within 2 weeks and to 93·8 ± 33·1 μmol/l after 4 weeks of pyridoxine treatment ( P <0·01) the mean reduction being 46% (32·0–56·1%). The decrease in plasma oxalic acid levels was most pronounced in patients with the highest pretreatment values. Two patients who received pyridoxine therapy prior to the beginning of the study had low initial values of plasma oxalic acid concentrations and showed no further decline.     

Radiological evaluation of post-traumatic tracheal stenosis using multidetector CT with multiplanar reformatted imaging and virtual bronchoscopy: Comparison with intraoperative findings

Aim

To evaluate the diagnostic utility of multidetector computed tomography (MDCT) (axial, multiplanar reformatted images and virtual bronchoscopy) in preoperative assessment of post-traumatic tracheal stenosis.

Materials and methods

Twenty-four patients with post-traumatic tracheal stenosis underwent tracheal resection anastomosis. The diagnosis was ascertained on the basis of history and rigid-bronchoscopy. All patients were preoperatively evaluated by MDCT. Intraoperative findings were used as the gold standard. Lesions were evaluated in terms of site, distance from the vocal cords, length, grade of the stenosis and length of the planned resected segment.

Results

The sensitivity of MDCT was 100%, 100%, 92.3%, 92.3%, 96% and its accuracy was, 100%, 100%, 96%, 96%, 88.8% in assessment of tracheal stenotic site, distance from the vocal cords, length, length of segment planned for resection and stenotic grade, respectively. MPR (coronal and sagittal reformatted) images were 100% sensitive in detecting stenotic site and distance from the vocal cord. It showed 92.3% sensitivity and 96% accuracy in assessment of the stenotic segment length and the length of segment planned for resection. VB showed 96% sensitivity and 88.8% accuracy.

Conclusion

MDCT with its various display modes improved the preoperative evaluation of post-traumatic tracheal stenosis. The combined interpretation of axial, multiplanar reformatted and VE leads to improved diagnostic confidence. We recommend it as a constant demand for preoperative evaluation of post-traumatic tracheal stenosis.     

Methoxistasis: Integrating the Roles of Homocysteine and Folic Acid in Cardiovascular Pathobiology

Over the last four decades, abnormalities in the methionine-homocysteine cycle and associated folate metabolism have garnered great interest due to the reported link between hyperhomocysteinemia and human pathology, especially atherothrombotic cardiovascular disease. However, clinical trials of B-vitamin supplementation including high doses of folic acid have not demonstrated any benefit in preventing or treating cardiovascular disease. In addition to the fact that these clinical trials may have been shorter in duration than appropriate for modulating chronic disease states, it is likely that reduction of the blood homocysteine level may be an oversimplified approach to a complex biologic perturbation. The methionine-homocysteine cycle and folate metabolism regulate redox and methylation reactions and are, in turn, regulated by redox and methylation status. Under normal conditions, a normal redox-methylation balance, or “methoxistasis”, exists, coordinated by the methionine-homocysteine cycle. An abnormal homocysteine level seen in pathologic states may reflect a disturbance of methoxistasis. We propose that future research should be targeted at estimating the deviation from methoxistasis and how best to restore it. This approach could lead to significant advances in preventing and treating cardiovascular diseases, including heart failure.     

多壁碳纳米管与活性炭吸附中分子毒素的比较

近年出现的多壁碳纳米管(MWCTs),因其有多空隙结构,高比表面积,高比表面能,高反应活性等决定其优异的吸附性能,非常有利于中分子毒物的吸附。本文的目的是研究MWCTs对中分子物质的吸附能力。我们选取维生素B12(VB12)作为中分子毒素的模拟物,分别利用扫描电子显微镜(SEM)和透射电子显微镜(TEM)观察MWCTs和商业用炭肾中活性炭的微观形貌,用紫外可见吸收光谱对比二者对VB12的吸附性能。实验中观察到MWCTs能形成发达的空隙结构,孔径多在中孔范围内。与活性炭相比,MWCTs的中孔孔隙结构远比活性炭发达,具有比活性炭更大的比表面积。通过Langmuir方程和Freundlich方程的拟合分析,VB12在MWCTs上的吸附为多分子层吸附,而在活性炭上的吸附类型更倾向于Langmuir模型对应的单分子层的吸附。MWCTs较活性碳有更快的吸附速率、更大的吸附量,可望成为新型的灌流器吸附剂。     

公共场所卫生监测管理系统应用软件的设计与实现

阐述公共场所卫生监测管理系统应用软件的设计与实现,分析系统功能需求和数据需求,介绍开发工具的选择,具体论述数据库设计、连接和程序设计过程。本系统已在实际业务工作中投入使用,有助于提高工作效率。     

Vitamin B6 deficiency: a potential cause of refractory seizures in adults

Objective: In children, vitamin B₆ (pyridoxine) deficiency has been described as a cause of seizures that are refractory to conventional antiepileptic medications. We describe the clinical presentation of 3 adults with refractory seizures (later diagnosed with vitamin B₆ deficiency) that resolved after pyridoxine treatment. Design: Case series. Setting: Tertiary care surgical intensive care unit. Patients: In the first case, a 54‐year‐old male with history of alcoholic cirrhosis developed new‐onset seizures refractory to phenytoin and levetiracetam 8 days after liver transplantation. In the second case, a 59‐year‐old male with hepatitis C infection developed intracranial hemorrhage and new‐onset seizures refractory to phenytoin, levetiracetam, and pentobarbital. The third patient is a 78‐year‐old male with a history of alcohol dependence who was admitted for an intraventricular bleed and developed new onset of refractory seizures. Interventions: Intravenous pyridoxine followed by oral pyridoxine. Measurement and Main Results: In all 3 cases, seizures persisted despite escalation of conventional antiepileptic medications but resolved within 2 days of pyridoxine supplementation. In each case, low serum pyridoxal 5′‐phosphate concentrations normalized with pyroxidine administration. Conclusions: Although refractory seizures caused by vitamin B₆ deficiency are rare in adults, it should be considered in critically ill adult patients with refractory seizures.     

双通道RP-HPLC法测定黄金搭档组合维生素片中VB1、VB2和VB6的含量

目的建立黄金搭档组合维生素片中维生素B1、B2和B6含量测定方法.方法用双通道反相高效液相色谱法进行分析.色谱柱为Lichrospher5-C18柱 ODS(5 μm,250 mm×4.6 mm),流动相为水-甲醇-0.25 mol*L-1庚烷磺酸钠溶液-乙酸-7%氨水(70:30:1.5:1:0.25),稀释液:同流动相,检测波长VB1248nm、VB2270 nm、VB6280 nm.结果峰面积与含量有良好的线性(γVB1=0.999920,γVB2=0.999993,γVB6=0.999 998);重复性好(批内RSDVB1=0.89%,RSDVB2=0.42%,RSDVB6=0.37%;批间RSDVB1=0.83%,RSDVB2=0.36%,RSDVB6=0.41%);回收率高(XVB199.3%,RSD=0.91%;XVB2100.1%,RSD=0.25%;XVB699.6%,RSD=0.46%).结论方法稳定,简便易行,快速准确,可作为此片剂质量检测方法.     

生物化学试题库的建立

介绍了用VB开发的生物化学题库系统的整体程序结构框图、各个板块的功能特点,以及如何导出空题库,使多人共同录入试题,完成题库的建设。实现了在VB应用程序中应用W ord的文档编辑功能,以及试卷的存档和随时浏览。