氟对SH-SY5Y神经细胞生物膜性脂质的作用

目的：深入了解氟中毒对神经细胞中生物膜性脂质结构的影响及其改变机制。方法：体外培养SH-SY5Y人脑神经母细胞瘤细胞，在培养液中加入不同浓度的氟化物或加入抗氧化剂，培养48h后用测定细胞MTT的方法来了解细胞的损伤程度，用高效液相色谱法分离和测定培养液中脂质过氧化物水平，用过柱和比色法测定细胞生物膜磷脂含量，用高效液相色谱法测定细胞生物膜辅酶Q和胆固醇含量。结果：经氟处理的神经细胞中MTT水平降低和脂质过氧化水平升高，呈现剂量依赖关系；高浓度氟处理的神经细胞中磷脂和辅酶Q含量减少，但胆固醇含量不变；加入维生素E后可减弱高剂量氟对生物膜性脂质的破坏作用。结论：氟中毒可引起SH-SY5Y神经母细胞瘤细胞生物膜性脂质结构发生异常改变，其机制可能与高剂量氟引起的自由基增多而对细胞生物膜造成的损害有关。     

Auditory frequency and intensity discrimination in pigmented rats

Auditory function was investigated in seven pigmented hooded rats (strain Long-Evans) with the aid of an operant conditioning procedure. Frequency difference limen was measured at frequencies from 0.5 to 64 kHz at 50 dB sensation level (SL). Weber ratios (frequency difference limen/frequency) in this range varied between 3.7 and 7.3%. The decline in the intensity of the stimulus from 50 to 10 dB SL was accompanied by a slight increase in the frequency difference limen. The frequency difference limen values were similar for frequency shifts upwards or downwards. Intensity discrimination was measured at 50 dB SL at frequencies of 2, 8 and 32 kHz. Intensity difference limen was frequency independent and amounted to 2.9 ± 0.5 dB in conditions of upward intensity shift. The values of intensity difference limen measured in conditions of downward intensity shift were significantly larger and amounted to 6.5 ± 1.6 dB. The characteristics of hearing function found in these experiments correspond with those described by other authors in albino rats and indicate that albinism in the rat has no significant influence on auditory frequency and intensity discrimination.     

Prevention of postoperative thromboembolism by various treatments

In 632 patients efficacy of dihydroergotamine (DHE) in preventing postoperative deep venous thrombosis (DVT) and pulmonary embolism (PE) was tested vs. low-dose heparin (LDH) by means of the ¹²⁵I-fibrinogen uptake test (RFUT). The incidence rate of DVT dropped from 36% (untreated group) to 17% after LDH, to 13% after DHE, and to 9% after simultaneous prophylaxis with both drugs. In patients with lower risk operations lasting not longer than 2 hs complete prevention of DVT was achieved by combined use of LDH and DHE.PE incidence in repeated lung perfusion scans of patients with positive RFUT was reduced to 4.3–2.6% (treated groups) in comparison to an incidence of 50% in the control group. This means the decrease of PE was overproportional in all treatment groups in comparison to the decrease of DVT incidence.The combined use of LDH and DHE may be considered as the best prophylactic regimen available for lowering postoperative DVT and PE.     

Penetration of delta-9-tetrahydrocannabinol and 11-OH-delta-9-tetrahydrocannabinol through the Blood-brain Barrier

Abstract The relative brain uptake (extraction into brain) of delta-9-tetrahydro-cannabinol (delta-9-THC) and the primary metabolite 11-OH-delta-9-tetrahydrocannabinol (11-OH-delta-9-THC) was measured after close intracarotid injection in rats of radiolabelled moities using labelled antipyrine as reference. The extraction percentage was of the same magnitude when injections were given in saline, 66 ± 11 % and 70 ± 9 % respectively after 5 sec., 59 ± 4 and 67 ± 8 respectively after 15 sec. While the extraction of 11-OH-delta-9-THC was the same when injected into plasma, the extraction of delta-9-THC was only about half of the extraction from saline, and also half the extraction of the metabolite from plasma. The higher uptake quantity of the metabolite into the brain may account for the relatively greater effect on the central nervous system of the metabolite than of the parent compound at equal concentrations in plasma. Moreover our experiments demonstrate that 11-OH-delta-9-THC formed in the liver after cannabis (delta-9-THC) administration may exert significant brain effects.     

Long-term monitoring of the mortality trend of Huntington’s disease in Austria

Recent increasing incidence and prevalence rates of Huntingtons disease (HD), a fatal neurodegenerative disorder, prompted us to investigate the epidemiological dynamic of HD in Austria during the period 1970–2001. Our study demonstrated a stable HD mortality rate throughout Austria of 0.125 per 100,000 individuals during the investigated period. The median age at death from HD was 56.5 years for both sexes and remained stable during the entire period observed, indicating no prolonged survival. An above average mortality rate from HD was observed in the north-eastern parts of Austria. Our data reflect the epidemiology of HD prior to and after the availability of genetic testing and provide a solid baseline for future investigations on the epidemiology of HD.This revised was published online in April 2005. In the previous version the article category was missing.     

Comparison of electrical velocimetry and transoesophageal Doppler echocardiography for measuring stroke volume and cardiac output

Background. Impedance cardiography (ICG) has been used extensivelyto estimate stroke volume (SV) and cardiac output (CO) fromchanges of thoracic electrical bioimpedance (TEB). However,studies comparing ICG with reference methods have questionedthe reliability of this approach. Electrical velocimetry (EV)provides a new algorithm to calculate CO from variations inTEB. As the transoesophageal Doppler echocardiographic quantificationof CO (TOE–CO) has emerged as a reliable method, the purposeof this study was to determine the limits of agreement betweenCO estimations using EV (EV–CO) and TOE–CO. Methods. Standard ECG electrodes were used for non-invasiveEV–CO measurements. These were placed on 37 patients scheduledfor coronary artery surgery necessitating transoesophageal echocardiographymonitoring. Simultaneous EV–CO and TOE–CO measurementswere recorded after induction of anaesthesia. EV–CO wascalculated using the Bernstein–Osypka equation. TOE–COwas measured across the aortic valve using continuous-wave Dopplerechocardiography and a triangular orifice model. Results. A significant high correlation was found between theTOE–CO and the EV–CO measurements (r²=0.86). Datawere related linearly. The slope of the line (1.10 (SE 0.07))was not significantly different from unity, and the point atwhich it intersected the ordinate (–0.46 (0.32) litremin^–1) was not significantly different from zero. Bland–Altmananalysis revealed a bias of 0.18 litre min^–1 with narrowlimits of agreement (–0.99 to 1.36 litre min^–1). Conclusions. The agreement between EV–CO and TOE–COis clinically acceptable, and these two techniques can be usedinterchangeably.      

Is the implantation of titanium stems in hip prostheses really obsolete?

AIM: Due to several bad results of studies, titanium is no longer used as an implant material in cemented total hip arthroplasty. This study attempts figure out by means of a meta-analysis if the material titanium itself was responsible for the bad results of some studies or if specific implant characteristics contributed to implant failure, independent of titanium. METHOD: Studies between 1960 and July 2002 were analysed concerning failure rates of cemented titanium total hip arthroplasties regarding their specific implant characteristics. RESULTS: Specific implant characteristics such as roughness of the surface and geometrical features led to significantly different failure rates. Stems of titanium with a dull surface and a wide proximal geometry could achieve such good results as those of the cobalt-chromium stems published in the study results of Malchau. CONCLUSION: Titanium is justified as a cementable material in total hip arthroplasty. By respecting specific implant characteristics, very good failure rates can be achieved. The high failure rates, published in several studies, are based upon implant characteristics which are not suitable for cementing techniques and not upon the implant material titanium itself.