Alpha and gamma motoneurons in the peroneal nuclei of the cat spinal cord: an ultrastructural study.

The aim of the present study was to investigate whether ultrastructural features can be used as a guide to identify alpha- and gamma-motoneurons among the intermediate-size neurons of the peroneal motor nuclei. The peroneus brevis and peroneus tertius muscles of adult cats were injected with horseradish peroxidase, and motoneurons labeled by retrograde axonal transport were examined by electron microscopy. In both nuclei, the distributions of cell-body diameters, measured in the light microscope, were bimodal covering the range of 28-84 microns, with a trough around 50 microns. The sample of 25 motoneurons selected for the ultrastructural study included not only large (presumed alpha) and small (presumed gamma) neurons but also intermediate-size cell bodies with diameters in the 40-60 microns range. For each motoneuron, 2-5 profiles were reconstructed from ultrathin sections taken at 6-8 microns intervals. Synaptic boutons were counted and their lengths of apposition were measured. On the basis of three criteria, namely: (1) bouton types present on the membrane, (2) percentage of membrane length covered by synapses, and (3) the aspect of the nucleolus, all the examined motoneurons, including those with intermediate sizes, fell into one of two categories. Fourteen motoneurons, with cell-body diameters in a range of 55-84 microns, were contacted by all types of boutons (mainly S-type with spherical vesicles, F-type with flattened vesicles, and C-type with subsynaptic cistern); the synaptic covering of the somatic membrane was over 40% and the nucleus contained a vacuolated nucleolus. These were considered alpha-motoneurons. Eleven motoneurons, with only S and F boutons, a synaptic covering under 30%, a compact nucleolus and a cell-body diameter ranging between 28 and 50 microns, were considered gamma-motoneurons. No other combination of the three criteria was observed. These results show that unequivocal distinction of alpha- and gamma-motoneurons is possible in the peroneal nuclei, on the basis of morphological differences independent of cell-body size.     

乳头溢液性疾病的高频超声与乳腺导管声学造影的对比研究

目的:探讨乳腺导管声学造影对乳头溢液性病变的诊断价值。方法:34例乳头溢液患者术前均行高频超声及声学造影检查,所有检查结果均与手术病理结果比较。结果:乳头溢液疾病高频超声及声学造影检查结果与手术病理结果比较诊断符合率分别为61.7%及79.4%,二者比较差异无统计学意义(P>0.05)。导管内乳头状瘤高频超声与声学造影诊断符合率分别为40%及73.3%,二者比较差异有统计学意义(P<0.05)。结论:乳腺导管声学造影可提高导管内小病变的检出率,显示详细的病变部位及扩张的导管,为手术提供重要的参考依据。尤其是导管内乳头状瘤声学造影检查明显优于高频超声检查。此种检查简单、方便、准确性较高,可作为乳头溢液性疾病的首选检查方法。     

Optimization of self-reference thermometry using complex field estimation.

Referenceless, or self-reference, thermometry is a technique for mapping temperature differences in the region of interest (ROI) using the baseline phase estimated by extrapolating the field in the surrounding region for estimation (RFE) and subtracting the estimated baseline from the measured field. In the present work a self-reference technique based on complex field estimation using 2D polynomials comprising complex-valued coefficients was proposed and optimized. Numerical simulations with a Gaussian-profiled phase distribution demonstrated that the ROI radius had to be 2.3-2.5 times the standard deviation (SD) of the Gaussian function in order to keep the error below 8% of the peak phase change. The area ratio between the ROI and the RFE had to be larger than 2.0 to maintain the error level. Based on the simulations, and phantom and volunteer experiments, the complex-based method with independently optimized polynomial orders for the two spatial dimensions was compared with the phase-based method using the similar-order optimization strategy. The complex-based method appeared to be useful when phase unwrapping was not removed. Otherwise, the phase-based method yielded equivalent results with less polynomial orders.     

超声显像与膀胱镜对膀胱肿瘤的诊断价值

对经手术和病理证实的８３例膀胱肿瘤进行超声显像和膀胱镜检查的对比性分析。结果表明，膀胱镜对膀胱肿瘤的诊断符合率为９７．５％，略高于超声显像符合率的９５．２％；但对膀胱肿瘤的术前分期，膀胱镜检查尚存在局限性，而超声显像可弥补膀胱镜检查的不足。本文超声显像对膀胱肿瘤的术前分期准确率达８９．５％。超声显像对小于０．５ｃｍ的小膀胱肿瘤之检出率不如膀胱镜高。因此在常规检查以及对肿瘤的术前分期时，应以超声显像作为首选，同时结合膀胱镜检查，可进一步提高膀胱肿瘤的术前诊断正确率。     

Separation discrimination with embedded targets

Previous research has shown that separation discrimination thresholds are independent of the internal spatial scale (local spatial frequency) of the targets whose separation is being judged. The experiments reported here tested the generality of this conclusion for separation discrimination of targets that were embedded in an array of identical objects, where crowding could enhance the importance of the scale at which the individual target locations are encoded. No effect of the local spatial scale of the targets was found under these conditions.     

Role of transrectal ultrasonography in the evaluation of azoospermic men with low-volume ejaculate.

OBJECTIVE: The purpose of this prospective study was to evaluate the incidence of distal ejaculatory system defects with transrectal ultrasonography (TRUS) among patients evaluated for azoospermia. METHODS: Forty-two patients with low-volume ejaculate and azoospermia were evaluated by physical examination, serum follicle-stimulating hormone and luteinizing hormone level determination, karyotyping, selective screening for cystic fibrosis mutations, and TRUS. RESULTS: On physical examination, in 29 patients (69%), either 1 (12 patients) or both (17 patients) of the vasa deferentia could not be palpated. In the group of 17 patients with bilateral involvement of the vasa deferentia, the ultrasonographic imaging universally showed bilateral absence or hypoplasia of the seminal vesicles with bilateral agenesis of the vasa deferentia and nonvisualization of both ejaculatory ducts. In the patients with a unilateral abnormality on physical examination, the ultrasonographic imaging showed absence of the ipsilateral seminal vesicle in 7 patients and the hypoplastic seminal vesicle in 5. In the group of 13 patients with normal physical examination findings, a variety of obstructive causes were diagnosed by TRUS examination. CONCLUSIONS: According to this study, TRUS appears to be a sensitive method for evaluating the anatomy of the distal ejaculatory system. Its safety and low costs make it a good alternative to the other invasive and expensive methods.     

单心室复合畸形超声诊断

目的 探讨单心室复合畸形的超声诊断。方法 总结我院经静脉造影和手术证实的9例单心室畸形的超声探查方法和结果。首先经仰卧位剑下探查，然后经胸骨旁、心尖切面、胸骨上窝切面完善和证实各种心内畸形并对比分析。结果 9例中男6例，女3例，年龄3．5～Il岁。其单心室均伴大动脉转位、心内畸形。结论 剑下切面可确认内脏心房位，初步确认大动脉关系硬心内畸形。多切面寻找室间隔或始基室间隔的位置和形态是鉴别诊断的关键，肺动脉发育状况可估测病情程度。     

Haemodynamic studies in early stroke

Summary We investigated prospectively a consecutive series of 81 patients suffering from acute middle cerebral artery (MCA) ischaemia by transcranial Doppler ultrasonography (TCD) within 24 h of the onset of symptoms. To monitor the haemodynamic changes follow-up recordings were carried out at short intervals during the next 2–3 weeks until stable haemodynamic status was achieved. In order to estimate the value of early TCD examinations in predicting the extent of brain damage seen later on, initial MCA flow reduction was correlated with infarction size and pattern on computed tomography. Fifty-three cases showed sufficient ultrasound penetration through the temporal bone. MCA flow asymmetries were recorded in 45 patients (85%); occlusion was observed in 17. Recanalization occurred in 11 patients followed by transient hyperaemia in 3, leaving residual stenosis in 2. Initial increase of flow velocities normalized within days or weeks in 7 out of 9 patients, while 2 developed residual MCA stenosis. Nineteen patients showed a considerable flow reduction on admission, which returned to normal in 9; transient hyperaemia was detected in 5 of these. Eight patients did not show any MCA flow asymmetry. Our study revealed very variable haemodynamic changes in acute stroke, which influenced further diagnostic and therapeutic management. The high rate of spontaneous recanalizations of MCA occlusions followed by transient hyperaemia in many cases has an important bearing on thrombolytic or theological therapy. Flow velocity differences could be related to infarction pattern rather than to infarction volume. Early MCA flow asymmetry recorded by TCD within the first 24 h could not reliably predict the extent of persistent brain damage or clinical outcome.     

高频喷射通气结合胸壁挤压对组胺致肺损伤犬呼吸循环功能的影响

以高频喷射通气结合胸壁挤压（ＨＦＪＶ＋ＣＷＣ）为通气模式，观察其对组胺致肺损伤犬呼吸循环功能的影响，并与单纯高频喷射通气（ＨＦＪＶ）进行比较。结果表明：与ＨＦＪＶ相比，ＨＦＪＶ＋ＣＷＣ时的功能残气量（ＦＲＣ）、ＰａＣＯ＿２和ＰＣＯ＿２均显著降低（Ｐ＜０．０１），肺泡通气量（Ｖ＿Ａ）和二氧化碳排出量（ＣＯ＿２）均显著增高（Ｐ＜０．０１），每分呼出气量（Ｖ＿Ｅ）、ＰａＯ＿２、ＰＣＯ＿２、吸气峰压（ＰＩＰ）、平均气道压（Ｐａｗ）、呼气末压（ＥＥＰ）、ＨＲ、平均动脉压（ＭＡＰ）、肺动脉压（ＰＡＰ）和肺毛细血管楔压（ＰＣＷＰ）均无显著变化（Ｐ＞０．０５）。提示：ＨＦＪＶ＋ＣＷＣ除保留单纯ＨＦＪＶ时气道开放、气道低压、良好的血液氧合、不影响循环功能等特点外，还具有增加呼气动力，改善肺泡通气，显著促进ＣＯ＿２排除等优点。