An improved method for thick film preparation using saponin as a lysing agent

Thick film examination for malaria is often hampered by the presence of cellular debris obscuring parasites. This is a major problem for diagnostic laboratories that do not have a high exposure to material identification. Films that are relatively free of cellular debris, allowing easier identification of parasites are an obvious advantage. Saponin has been used by researchers to liberate malarial parasites for harvesting from infected erythrocytes. It has also been used for thick film preparations for diagnosis, but has not gained widespread acceptance, possibly due to the persistence of cellular debris inherent in the technique. In the present study the saponin method for thick film examination has been modified by the inclusion of a centrifugation step to remove cellular debris. Thick films were run in parallel with films made using the standard Fields stain technique and the original saponin. Results indicate that the modified saponin technique provides superior preparations free of cellular debris.     

Auditory Pathway Function after Vestibular Schwannoma Surgery

We studied seven patients before and after vestibular schwannoma surgery. Four patients became unilaterally profoundly deaf and three patients preserved their hearing. Cortical responses were recorded with a 122-channel whole-scalp SQUID neuromagnetometer using tone-burst stimuli to the healthy ear. Brainstem auditory evoked potentials (BAEPs) were measured using alternating clicks. Ten healthy volunteers served as a control group. In patients, preoperative cortical response latencies and strengths did not differ significantly from those of controls. However, 6 months after the operation the latency was, on average, 7 ms longer than preoperatively over both hemispheres. BAEPs were in the normal range both before and after the operation. These results suggest that unilateral lesion in peripheral auditory pathways also affects cortical reactivity to stimuli presented to the non-affected ear, possibly reflecting altered binaural interaction in the auditory pathways.     

磁场对小鼠肿瘤生长的影响

本文研究了低频交变磁场和稳恒磁场对小鼠致癌的影响。实验结果表明，磁场强度为15mT的50Hz交变磁场和80mT的稳恒磁场均能提高机体的免疫功能；对肿瘤组织的供血情况有明显抑制效果，且磁场使肿瘤组织内形成较丰富的间质纤维；使肿瘤细胞坏死明显增多。     

Collum intertextum—a case report of a campanological crisis

A case is reported of a 9-year-old boy who was lifted into the air when a bell ringing rope caught round his neck. No serious injury resulted.     

Changes of cutaneous receptive fields of spino-cervical-tract neurones and other dorsal horn neurones by microelectrophoretically administered amino acids

Summary Extracellular recording of 320 neurones in the dorsal horn (L 7) were performed in cats by means of multibarrelled electrodes. Changes of cutaneous receptive field size and responsiveness to tactile stimulation induced by microelectrophoretic application of exciting (glutamic acid — GLA; homocysteic acid — HCA) and depressing (glycine — GY; and gamma-amino-butyric acid — GABA) amino acids were studied on cells giving origin to the spino-cervical tract (SCT) as well as on other unidentified dorsal horn cells (NON-SCT-neurones). Two types of SCT-neurones were distinguished.An unexpected finding was that in most type I SCT-neurones low doses of GLA induced increased excitability but higher doses of GLA could not induce a depolarization block and very often led to a decrease in cell excitability. Recordings obtained with double-multibarrelled electrodes are very suggestive that this biphasic effect of GLA is mediated via inhibitory interneurones induced by the spreading of GLA.In almost all type II SCT-neurones and NON-SCT-neurones GLA induced increase of excitability leading to a depolarization block at high doses. Such changes were accompanied by a considerable increase of receptive field size and responsiveness to mechanical stimulation. In all types of cells GY induced a shrinkage of the receptive field and also reduced sensitivity. In most dorsal horn cells encountered in this study cooling at thoracic level produced an increase in field size and sensitivity. GLA could induce a further increase when applied at the same time, however.     

一定强度静磁场可促进许旺细胞快速分泌神经生长因子

背景：国内外对静磁场加载许旺细胞的研究较少,对其产生的生物学效应尚不清楚。目的：探索静磁场对许旺细胞分泌神经生长因子水平的影响。方法：将传代良好的许旺细胞随机分为3组,分别为0.05 mT静磁场组、0.1 mT静磁场组、空白对照组。从接种第2天即开始静磁场加载,每天曝磁12 h,空白对照组不进行静磁场加载。加载6 d后利用RT-PCR技术检测许旺细胞中神经生长因子mRNA的表达,ELISA技术检测许旺细胞分泌神经生长因子水平。结果与结论：静磁场组培养上清中神经生长因子mRNA的表达和分泌神经生长因子水平显著高于空白对照组(P < 0.05);0.1 mT静磁场组神经生长因子mRNA的表达和分泌神经生长因子水平虽高于0.05 mT静磁场组,但是差异无显著性意义(P >0.05)。结果表明一定强度的静磁场可以促进许旺细胞快速分泌神经生长因子。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

Acute Childhood Leukemias and Exposure to Magnetic Fields Generated by High Voltage Overhead Power Lines - A Risk Factor in Iran

Many investigators have studied the effects of Extremely Low Frequency-Magnetic Fields generated byordinary and domestic power lines, as a risk factor in acute leukaemias of children, but there are limitedinformation available regarding very high voltage overhead power lines. Children in developing countriessometimes live very close to such structures and we have registered several patients with acute leukaemiasappearing in clusters. In the present study we have analyzed 60 consecutively diagnosed patients with acuteleukaemias, and 59 matched controls in a provincial capital city in North-Western Iran. After provision ofconsent, a detailed form was filled in, and a visit to the present (or previous) residential areas of both groups wasarranged. The locations of the very high voltage power lines (123, 230, 400 kilo volts), were noted in each area,if present, and their distances from the houses under study were detected. The expected intensities of the MagneticFields (B) were calculated having the mean intensity of the electrical current and other line characteristics, bymeans ofÅırelevant equations. Fourteen patients in the case group (23.5%) were living near the high voltagepower lines in distances ≤ 500 meters. (Mean B = 0.6 microTeslas, μT). In the control group at the same distance,the figure was 2 children (3.3%) (Mean B = 0.35 μT). Statistically, the likelihood of leukaemia was increasedconsiderably in this distance (Odds ratio (OR) = 8.67, 95% Confidence Interval (CI) = 1.74- 58.4, P value=0.001). On the other hand 15 pts(25 %) in the leukaemia group were experiencing Magnetic fields above 0.45‌μT in comparison to 5 in the control group ( 8.5% )(OR = 3.60, 95% CI = 1.11-12.39, P = 0.01). More childrenin developing countries like Iran live close to very high voltage lines, and they experience relatively more harmfuleffects from the Magnetic Fields, in comparison with children in developed countries. Residence near very highvoltage overhead power lines, in distances ≤500 meters, and Magnetic Fields > 0.45 μT, should be considered arisk factor for the pathogenesis of acute leukaemias in children.     

Duration of handwashing in intensive care units: a descriptive study

The duration of handwashing was studied in two community hospitals (teaching and nonteaching). The duration in seconds of 180 handwashes by health care personnel and 52 handwashes by non-health care personnel were recorded. The mean duration for health care personnel was 8.62 +/- 0.29 SEM; the degree of patient contact did not influence the duration of handwashing. The duration of handwashing was two times longer in health care personnel vs. non-health care personnel (8.62 +/- 0.29 vs. 4.14 +/- 0.42; t = 7.7; p less than 0.001). Comparisons revealed no statistically significant difference in duration between personnel at teaching and nonteaching hospitals or among those in different occupations. The data indicate that the duration of handwashing among health care personnel is below the standard recommended by authorities in hospital infection control. This may be an important factor in the transmission and persistence of nosocomial infection in critical care units. The antimicrobial efficacy of handwashing agents should be reevaluated considering the actual duration of handwashing by health care personnel within the hospital environment or efforts should be made to increase the duration of handwashing.     

A shared cortical bottleneck underlying Attentional Blink and Psychological Refractory Period

Doing two things at once is difficult. When two tasks have to be performed within a short interval, the second is sharply delayed, an effect called the Psychological Refractory Period (PRP). Similarly, when two successive visual targets are briefly flashed, people may fail to detect the second target (Attentional Blink or AB). Although AB and PRP are typically studied in very different paradigms, a recent detailed neuromimetic model suggests that both might arise from the same serial stage during which stimuli gain access to consciousness and, as a result, can be arbitrarily routed to any other appropriate processor. Here, in agreement with this model, we demonstrate that AB and PRP can be obtained on alternate trials of the same cross-modal paradigm and result from limitations in the same brain mechanisms. We asked participants to respond as fast as possible to an auditory target T1 and then to a visual target T2 embedded in a series of distractors, while brain activity was recorded with magneto-encephalography (MEG). For identical stimuli, we observed a mixture of blinked trials, where T2 was entirely missed, and PRP trials, where T2 processing was delayed. MEG recordings showed that PRP and blinked trials underwent identical sensory processing in visual occipito-temporal cortices, even including the non-conscious separation of targets from distractors. However, late activations in frontal cortex (> 350 ms), strongly influenced by the speed of task-1 execution, were delayed in PRP trials and absent in blinked trials. Our findings suggest that PRP and AB arise from similar cortical stages, can occur with the same exact stimuli, and are merely distinguished by trial-by-trial fluctuations in task processing.