Fine-needle aspiration cytology of pancreatic somatostatinoma: the importance of immunohistochemistry for the cytologic diagnosis of pancreatic endocrine neoplasms

Pancreatic somatostatinoma is a rare pancreatic endocrine neoplasm representing as little as 1% of pancreatic endocrine neoplasms (PENs). The histologic features of this tumor are like those of other PENs, except that it commonly forms acinar structures and often has cells with abundant, granular cytoplasm. We have recently encountered two of these neoplasms sampled by endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA). We discuss the cytologic and immunohistochemical findings of these two cases and the cytologic similarities these neoplasms share with pancreatic acinar-cell carcinoma (PACC). We review the cytologic features of PEN and PACC and discuss the importance of cell block immunohistochemistry in the diagnosis of pancreatic neoplasia sampled by EUS-guided FNA.     

Shear Rate Dependence of Ultrasound Backscattering from Blood Samples Characterized by Different Levels of Erythrocyte Aggregation

The objectives were (1) to determine the effect of the erythrocyte aggregation level (wide range of aggregation) and shear rate (which also affects aggregation) on the ultrasound backscattered power, and (2) to evaluate the reproducibility of the ultrasound method. Experiments were performed under steady flow (100–1250 ml/min) in a 12.7 mm diameter vertical tube. Doppler ultrasound at 10 MHz was used to measure simultaneously the velocity and the backscattered power across the tube. For each radial position, the shear rate was computed from the derivative of the velocity profile. The backscattered power decayed exponentially as a function of the shear rate, and for a given shear rate, the power increased monotonically with the level of aggregation measured by laser reflectometry. Using blood samples simulating hypo-, normal, and hyperaggregating erythrocytes, the power of the ultrasound signal varied respectively by –7.8, –13.2, and –16.1 dB as a function of the shear rate (from 0.4 to 50 s^–1). The reproducibility of the backscattered power was 5.5 dB, which is less than the variations observed as a function of the shear rate. In conclusion, ultrasound backscattering is sensitive to the level of erythrocyte aggregation. At a first glance, ultrasound seems less accurate when compared to laser reflectometry but it is suggested that this is because ultrasound backscattering may be sensitive to structural aggregate changes that are not detected by the laser method. © 2000 Biomedical Engineering Society. PAC00: 8718-h, 8719Tt, 8750Kk     

低频超声透皮给药的研究进展与应用

低频超声可以增强包括大分子药物在内的许多药物的透皮传输,其主要机制是超声的空化作用,大多数人认为是通过改变角质层角化细胞排列结构来提高皮肤渗透能力的.低频超声透皮给药已被人们用于离体实验和动物活体实验,到目前为止,无论是小分子透皮传输还是大分子透皮传输都有很多成功的例子.但是真正通过低频超声透皮导入药物进行治疗的临床应用报道很少,需要更进一步大量的临床试验以确定其安全性与实用价值.一旦其安全性得以证实,合适的低频超声透皮仪研制成功,低频超声快速透皮必将成为一种安全、有效、可控、经济的新型给药方式.     

Priority of blood flow to splanchnic organs in humans during pre- and post-meal exercise

Cardiac output and superior mesenteric arterial flow in five healthy young men were followed using Doppler ultrasound techniques at rest and during 4 min bouts of bicycle exercise in both a pre- and a post-meal situation. The meal given was mixed and heavy, with an energy content (related to body size) of about 1400–1600 kcal (5.9-6.9 MJ). Two levels of exercise, 50–65 W and 150–200 W (about 75% of Vo_tmax), were tested, with the subjects cycling in a reclining position. Superior mesenteric arterial flow increased threefold, to about 1.11 min^-1, after the meal. During exercise in the fasting situation there were only modest changes in splanchnic vascular conductance, and moderate increases in superior mesenteric arterial flow were actually recorded. Exercise in the post-prandial state caused appreciable reductions in splanchnic vascular conductance, and a 38% reduction was observed during the most heavy exercise. However, not even such a decrease in conductance resulted in any definite reduction in superior mesenteric arterial blood flow, which was maintained at the pre-exercise level. Cardiac output increased by about 1.3 1 min^-1 after the meal. The exercise-induced increases in cardiac output were of the same order in the fasting and in the post-prandial state. Variance analyses showed the high cardiac output levels reached during postprandial exercise to be no different from levels that would be reached by pure summation of the changes caused by eating alone and by exercise alone. It is concluded that blood flow to the splanchnic organs in reclining man retains its high pre- and post-prandial priority during short exercise bouts of up to 75% of Vo_Smax.     

Developments in cardiovascular ultrasound. Part 2: Arterial applications

Many of the changes resulting from arterial disease can be measured, using Doppler ultrasound for measurement of blood velocity and B-scan imaging for measurement of tissue structure and composition. Wall thickness, the degree of arterial narrowing and plaque volume can be measured using B-scan imaging, and 3D ultrasound can be used to improve the accuracy of measurements of plaque volume and for improved visualisation of complex arterial geometries. Measurement of the dynamic properties of the arterial wall permits estimation of wall elasticity and plaque motion. From the Doppler signal, measurements of blood velocity are used to estimate the degree of arterial narrowing and volumetric flow, although measurement errors can be large. Wall shear stress can be estimated by measuring the velocity gradient at the vessel wall. The problems of inadequate spatial resolution and interference from overlying tissue are largely removed when intravascular systems are used, and these have superior capability in the assessment of arterial structure and tissue composition. However, measurement of quantities relating to blood flow is more difficult using the intravascular approach, as the indwelling cather disturbs the blood flow pattern, and currently, assessment of flow and vessel cross-section are not performed at the same site.     

Prenatal diagnosis of a complete mole coexisting with a dichorionic twin pregnancy: case report

A complete mole coexisting with dichorionic twins was diagnosed by the combined use of sonography and chorionic villus sampling at 10 weeks gestation. The pregnancy resulted in the death of one fetus at 31 weeks from presumed feto-maternal haemorrhage, while the other fetus survived in good condition. A summary of the available literature, combined with this report, reveals a total of seven pregnancies with twins and a coexistent complete mole. Only two out of 14 fetuses survived. Maternal complications included one case of pre-eclampsia and one persistent trophoblastic tumour. Accurate diagnosis of complete mole is possible by genetic analysis of chorionic villi obtained with standard transabdominal sampling. Twins with a coexistent complete mole will usually undergo miscarriage. However, fetal survival is possible and the maternal risks seem limited. A concomitance between gestational trophoblastic disease and the occurrence of feto-maternal haemorrhage is observed.     

Endoscopic ultrasound-guided fine-needle aspiration cytology of peripheral nerve-sheath tumors

Endoscopic ultrasound (EUS) has allowed for the fine-needle aspiration and diagnosis of many different gastrointestinal neoplasms, including mesenchymal tumors. Although most mesenchymal tumors of the gastrointestinal tract are gastrointestinal stromal tumors (GISTs), other mesenchymal tumors, including neural tumors, do occur. Proper diagnosis and differentiation of these tumors from GISTs are important because of their different prognoses and treatment regimens. We encountered three peripheral nerve-sheath tumors of the gastrointestinal tract aspirated by EUS (two schwannomas and a granular-cell tumor). We report on the endoscopic ultrasound, cytologic, histologic, and immunohistochemical findings of these cases.     

心腔内导管超声在腹膜后脏器显像中应用研究

目的通过动物实验评价心腔内导管超声探头对部分腹膜后脏器结构的显像效果，以及其用于腹膜后脏器显像的可行性。方法静脉鞘管引导心腔内导管超声探头进入下腔静脉，通过对8只实验犬部分腹膜后脏器的近距离超声成像，记录成像过程动物生理参数，观察其二维图像及彩色血流显像效果，并与常规经腹超声检查效果比较。结果实验前与腔内显像过程中犬的心率、动脉压、呼吸频率差异无统计学意义（P〉0．05）；心腔内导管超声可清晰显示肾脏、肾上腺、大血管旁淋巴结等腹膜后脏器的二维细微结构及彩色血流分布，成像质量明显优于经腹切面的显示效果。结论采用心腔内导管超声观察腹膜后部分脏器的结构是安全可行的，成像质量明显优于经腹切面的显示效果，对肾上腺及其血供的显像尤为清晰。心腔内导管超声在腹膜后脏器显像方面有重要应用价值，为腹膜后脏器的超声检查提供了一种新方法。     

利用磁共振成像实现肿瘤热疗中实时无创测温的方法

肿瘤热疗特别是高强度聚焦超声（HIFU）技术，已成为一种重要且非常具有前景的肿瘤治疗方法，温度是直接决定热疗效果的重要参数，实时准确的进行深部无创测温是目前制约肿瘤热疗进一步发展的一项关键技术。近来利用磁共振成像（MRI）进行无创测温，正受到越来越多的研究者的重视。本文简述了MRI无创测温的三种方法，比较了不同测温原理的特点和适用条件，报道了已有研究发展状况，并介绍了尚待解决的问题。     

Uterine contractility decreases at the time of blastocyst transfers

High-frequency uterine contractions at the time of non-cavitating embryo transfer influence adversely IVF-embryo transfer outcome. This prompted us to quantify prospectively the possible decline in uterine contraction frequency occurring during later stages of the luteal phase of ovarian stimulation, up to the time of blastocyst transfers, in 43 IVF-embryo transfer candidates. Contractility was assessed on the day of human chorionic gonadotrophin (HCG) administration, 4 days after HCG (non-cavitating embryo transfer; HCG + 4), and 7 days after HCG (blastocyst transfers; HCG + 7). For this, 2 min sagittal uterine scans were obtained by ultrasound and digitized with a computerized system for the assessment of uterine contraction frequency. Our results indicated that a slight, yet significant, decrease in uterine contraction frequency, observed from the day of HCG (4.4 +/- 0.2 contractions/min) to HCG + 4 (3.5 + 0.2 contractions/min), was followed by a more pronounced, additional decrease between HCG + 4 and HCG + 7 (1.5 +/- 0.2 contractions/min; P < 0.001). In conclusion, during the luteal phase of ovarian stimulation, uterine contractility decreases progressively, and reaches a nearly quiescent status 7 days after HCG administration, at the time of blastocyst transfers. It is possible that such a uterine relaxation assists blastocyst implantation.