Asymmetry of Doppler spectrum in stenosis differentiation

The asymmetry of the spectral distribution of ultrasonic Doppler flow velocity signals, assessed using the coefficient of skewness, is discussed as a criterion of stenosis differentiation. Its performance is compared with that of the index of turbulence intensity for both in vitro and in vivo flow Doppler signals, recorded distal to a stenosis. The power spectral distributions are computed using the direct Fourier transform and maximum likelihood method. The asymmetry of spectral distribution has proved to be a more efficient criterion than the turbulence intensity. The maximum likelihood method ensures better stenosis differentiation than the direct FFT method.     

局灶性脑梗死后半暗带区皮层血流量与神经细胞凋亡的实验研究

目的：研究大鼠局灶性脑梗死后半暗带区皮层血流量及神经细胞凋亡。 方法： 光化学法诱导大鼠局灶性脑梗死模型，应用激光多普勒微循环测量仪检测局灶性脑梗死后各时间点坏死区和半暗带皮层血流量；TdT-介导dUTP-生物缺口末端标记（TUNEL）法检测凋亡细胞。 结果： 脑梗死后坏死区皮层血流量呈波浪样改变，3 h降至最低，为正常血流量的9.36%±1.72%，6h后回升，12 h达高峰，为正常31.18%±1.44%，24-48 h血流量再度下降，与3 h相比无显著差异（P＞0.05）。半暗带皮层血流量6 h降至最低，为正常皮层血流量的30.88%±7.11%，9-48 h上升，至48 h血流恢复至正常91.90%±4.56%，与其它组差异显著 (P<0.05)。TUNEL结果显示，局灶性脑梗死组 6 h 开始出现凋亡细胞，主要集中于半暗带区，呈半球状向四周放射样扩展，随梗死时间的延长凋亡细胞逐渐增多，梗死48 h后凋亡细胞达峰值。 结论： 局灶性脑梗死后半暗带区皮层血流量与神经细胞凋亡具有明显的关系，其血流量的恢复引起的再灌注损伤最终导致了迟发性神经细胞凋亡。     

ACE Genotype May Have an Effect on Single versus Multiple Set Preferences in Strength Training

A polymorphic variant of the human angiotensin converting enzyme (ACE) gene was identified. The 'D' (rather than 'I') variant was associated with improvements in strength related to physical training. We set out to determine whether the response to different patterns of strength training might also differ. Ninty-nine Caucasian male non-elite athletes were randomly allocated into one of three groups: 31 non-training/control (CG: 31), single-set (SSG: 35) and multiple-set (MSG: 33). SSG and MSG trained three times a week for 6 weeks. Both training groups were underwent a strength-training program with two mesocycles (12-15 repetition maximum (RM) and 8-12 RM mesocycles). One RM loads in half squat and bench press were assessed before training and after the first and second mesocycles. ACE polymorphisms analysed by polymerase chain reaction (PCR) methods. Subjects with ACE II genotype in the MST group had improved strength development in 12-15 RM, while SST and MST groups had similar gains in 8-12 RM. Subjects with ACE DD genotype in both the SSG and the MSG had similar benefits from both 12-15 RM and 8-12 RM. Strength gains for subjects with ACE ID genotype in the SSG were similar to MSG gains in response to 8-12 RM loads but not with 12-15 RM loads. Additionally, subjects with DD genotype had superior strength gains in both strength training groups. Tailoring strength training programmes (single-set vs. multiple set) according to the athlete's ACE genotype may be advantageous.     

Zur histogenese und cytogenese des tapetum lucidum cellulosum der katze

Zusammenfassung Die postnatale Entwicklung des Tapetum lucidum cellulosum der Katze wird mit licht- und elektronenmikroskopischen Methoden untersucht. Bereits am ersten postnatalen Tag sind im Bereich des prospektiven Tapetum zwei Zellarten voneinander zu unterscheiden: 1. mesenchymale Bindegewebszellen und 2. prospektive Tapetumzellen, die durch elektronendichte Tapetumstäbchen gekennzeichnet sind. Die Mesenchymzellen unterteilen als parallel zur Retinaoberfläche ausgebreitete Zellplatten in der Choriodea am hinteren Augenpol den weiten extracellulären Raum in 20–25 etwa 5 m hohe Schichten. Die Tapetumzellen liegen zwischen den Mesenchymzellplatten und wachsen im Verlaufe der ersten vier postnatalen Wochen innerhalb der Schichten in die Breite, bis sie den extracellulären Raum vollständig ausfüllen und als polygonale Zellen direkt aneinander grenzen. Im weiteren Verlauf der Entwicklung werden die Mesenchymzellplatten rückgebildet, so daß bei der adulten Katze die Tapetumzellschichten direkt übereinander liegen und nur von Netzen elastischer und kollagener Fasern getrennt sind.Die von einer Elementarmembran umgebenen Tapetumstäbchen enthalten einen elektronendichten, in den ersten postnatalen Wochen mit einer Periode von 100 Å quergestreiften Kern. Zunächst nehmen sie an Zahl und Länge zu und füllen am Ende der vierten postnatalen Woche, zu Bündeln von parallel verlaufenden Stäbchen geordnet, das Cytoplasma der Tapetumzellen. Dann nehmen die Tapetumstäbchen an Dicke zu, und ihre Querstreifung wird von einem elektronendichten Material überlagert. Die Entwicklung der Tapetumstäbchen hat eine starke Ähnlichkeit mit der in der Literatur beschriebenen Entwicklung von Melanosomen in Melanocyten. Das Tapetum lucidum cellulosum wird als ein dichter Verband hochdifferenzierter extrakutaner Melanocyten angesehen.

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Summary The postnatal development of the tapetum lucidum cellulosum of the cat was studied by light and electron microscopy. Already by the first postnatal day two cell types can be distinguished in the prospective tapeta area: 1. mesenchymal cells and 2. prospective tapetal cells, characterized by electron dense, membrane bound, rod-like inclusions. The flattened mesenchymal elements form 20–25 separate layers of cells, which are arranged parallel to the surface of the retina, subdividing the extracellular space of the chorioidea at the posterior pole of the eye into 5 m high compartments. These compartments contain the tapetal cells which enlarge (in their longitudinal axis) during the first four weeks post partum until they occupy the extracellular space almost completely. At this stage, the tapetal cells are polygonal in shape and closely attached to each other. During the subsequent period of development there is a gradual involution of the mesenchymal cell plates. Thus, in adult cats the individual layers of tapetal cells are only separated from each other by networks of collagen and elastic fibers.The tapetal rods are bound by unit membranes and contain an electron dense core which, during the early postnatal weeks, exhibits a periodic cross-striation (100 Å). The tapetal rods increase in number and length during the first four weeks post partum; by the end of the fourth week, they occupy the whole cytoplasm of the tapetal cells. Parallelly arranged rods are grouped into individual bundles coursing inside the cytoplasm in different directions. Thereafter, the tapetal rods increase in thickness and their cross-striation becomes obscured by an electron dense material. This development of the tapetal rods closely resembles that of melanosomes.Thus the tapetum lucidum cellulosum can be regarded as a compact tissue made up of modified extracutaneous melanocytes.

Auszugsweise vorgetragen auf der 69. Versammlung der Anatomischen Gesellschaft in Kiel, Juni 1974.     

鼻咽癌调强放射治疗的剂量验证

目的:对接受调强放射治疗的鼻咽癌病人进行治疗前的剂量验证.材料和方法:利用电离室,胶片和验证模体对39个接受调强放射治疗的鼻咽癌患者,在治疗开始前进行绝对剂量和相对剂量验证.绝对剂量验证主要在两个位置进行:一个在等中心位置,另一个在离等中心4cm靠进腮腺的位置.相对剂量主要用体模对单野和整个计划的剂量分布进行验证.将得到的剂量分布利用分析软件与计划中的剂量分布进行分析比较.利用剂量偏差(dose difference)、吻合距离(distance to agreement,DTA)、γ指数等参数来测量剂量验证的偏差.结果:中心点和腮腺边上点的平均绝对误差分别为2.70%和3.03%.对于测量感兴趣区域(ROI,region of interested)的相对误差的测量,90%的测量都在设定的标准(3%,3 mm)之内,对于未能达到剂量偏差和间距偏差标准的区域,结合γ分析后一般也可以得到满意的结果.结论:验证结果表明实际测量剂量分布与计划计算的剂量分布符合的相当理想.     

Ganglioglial Differentiation in Medulloblastoma

A case of cerebellar medulloblastoma with clusters of mature ganglion cells and glial cells is described. The patient, a 15 -year -old girl, underwent three operations followed each time by radiation and chemotherapy during the four-year clinical course. Histologically, the ganglion cells were clearly identifiable by their abundant eosino-philic cytoplasm, round nuclei with prominent nucleoli, tigroid granules, and argyrophilic fibrils and axons. Im-munohistochemically, the cells were NSE- and NF positive, and ultrastructurally they contained abundant tubules and filaments, neurosecretory granules and well developed rough endoplasmic reticulum. There were many cells transitional in appearance between primitive cells and mature ganglion cells. The tumor also had many mature yet atypical astrocytes and oligodendrocytes. The exact mechanism of the extensive neuronal and glial maturation of medulloblastoma cells is unclear, but the repetitive surgical interventions, radiation and chemotherapy might have had certain cytostatic effects on rapidly dividing medulloblastoma cells, giving them a chance to mature into postmitotic cells with potential for neuronal and glial differentiation. Acta Pathol Jpn 40: 50–56, 1990.     

Genetic and light intensity effects on the activity and emigratory behavior of the house fly,Musca domestica (L.)

The emigratory behavior and locomotor activity of yellow-eyed (y/y), wildtype (+/+), and heterozygous (+/y) house flies was examined at 8 fc (86 lx) and 1600 fc (17,223 lx) light intenstities. At 8 fc, emigration rate and activity of the y/y flies was similar to that of the +/+ and +/y flies. However, at 1600 fc, the y/y flies emigrated at twice the rate and showed an activity of about one-third that of the other genotypes. The behavior of the +/+ and +/y flies remained similar regardless of the experimental design or light intensity. The excessive neural stimulation by high-intensity light resulting from reduced shielding pigments led to behavioral modifications in the visual and tactile responses of the y/y flies.This research was supported in part by grants from the CUNY Faculty Research Award Program (No. 1103) and NIH Biomedical Research Support Grant 5-S05-R-07064.     

不同运动强度对骨质疏松影响的数值模拟

探讨数值模拟不同运动强度对因废用引起的骨质疏松的影响。依据骨的功能适应性和力学调控系统理论,遵循骨重建的生理过程,建立了一个带有时间历程的描述松质骨骨质疏松过程的计算模型,用C语言编制程序。得到了不同运动负荷对因废用引起的骨质疏松(孔隙率)的影响曲线。结果表明:较大的运动强度可以减缓因废用引起的骨质疏松。这对于运动防治骨质疏松有一定的参考价值。     

Calibration of Earphone-Transmitted Sounds

The intensity of acoustic stimulation is frequently a variable of interest in psychophysiological studies but calibration procedures, particularly when earphones are employed, are not always adequate. The present study demonstrates that intensity is underestimated, more seriously at low frequencies, when calibration does not employ an appropriate coupler. Several standardized calibration methods are discussed in terms of their suitability For routine laboratory use.     

Effects of Stimulus Intensity on Cardiovascular Activity

A between-groups design (N = 75) was employed to investigate the effects of stimulus intensity and repetition on cardiovascular activity. It was predicted that as intensity increased, the pattern of physiological activity would change, indicating a transition from the orienting to the defense reflex. Cardiovascular activity was represented by measures of heart rate, digital pulse amplitude, and cephalic blood content. Subjects received 12 presentations of a 1000 Hz tone of 45, 60, 75, 90, or 105 dB. Stimulus risetime was 30 msec and the duration 2 sec. Analyses of variance revealed reliable effects of intensity and repetition on all cardiovascular variables. However, neither these results nor additional multivariate analyses supported the differentiation of orienting and defense reflexes as suggested by Sokolov (1963) or Graham (1979). The importance of the startle reflex in the interpretation of these findings was discussed.