A framework for evaluating image segmentation algorithms.

The purpose of this paper is to describe a framework for evaluating image segmentation algorithms. Image segmentation consists of object recognition and delineation. For evaluating segmentation methods, three factors-precision (reliability), accuracy (validity), and efficiency (viability)-need to be considered for both recognition and delineation. To assess precision, we need to choose a figure of merit, repeat segmentation considering all sources of variation, and determine variations in figure of merit via statistical analysis. It is impossible usually to establish true segmentation. Hence, to assess accuracy, we need to choose a surrogate of true segmentation and proceed as for precision. In determining accuracy, it may be important to consider different 'landmark' areas of the structure to be segmented depending on the application. To assess efficiency, both the computational and the user time required for algorithm training and for algorithm execution should be measured and analyzed. Precision, accuracy, and efficiency factors have an influence on one another. It is difficult to improve one factor without affecting others. Segmentation methods must be compared based on all three factors, as illustrated in an example wherein two methods are compared in a particular application domain. The weight given to each factor depends on application.     

缺血性卒中或短暂性脑缺血发作患者的卒中预防指南

这份新声明旨在为缺血性卒中或短暂性脑缺血发作存活者的缺血性卒中预防提供全面和及时的循证推荐，循证推荐包括对危险因素的控制，动脉粥样硬化性疾病的干预措施，心源性栓塞的抗栓治疗以及非心源性卒中抗血小板药的应用。另外，还为其他多种特殊情况下复发性卒中的预防提供了推荐、包括动脉夹层分离、卵圆孔未闭、高同型半胱氨酸血症、高凝状态、镰状细胞病、脑静脉窦血栓形成、女性卒中（特别是与妊娠和绝经后激素替代治疗相关卒中），脑出血后肮凝药的应用，以及该指南在高危人群中执行和应用的特殊措施。     

Effects of intrathecal and intraperitoneal morphine on gastrointestinal motility in the rat.

A method has been developed to compare gastrointestinal (GI) transit time after intrathecal (i.t.) drug injection in the rat. Each animal had a catheter implanted in the i.t. space. Eight rats, on three separate occasions, had either i.t. morphine 16 micrograms kg-1 (in 50 microliters) or intraperitoneal (i.p.) morphine (0.1%) 7.5 mg kg-1 or i.t. saline (50 microliters). The dose of morphine was the ED50 for analgesia by each route. After halothane and oxygen anaesthesia, 10 steel balls and 1 ml of contrast medium were placed into the stomach, the whole procedure being completed within 5 min. Radiographs were taken at 5 min, 3, 6 and 24 h, and the number of balls in the stomach, small and large intestine were counted. The inhibitory effect of i.t. or i.p. morphine on gut motility caused an equally significant delay at 6 h. In a separate series of eight rats the delay by i.t. morphine could be completely antagonized by i.p. naloxone 1 mg kg-1. Thus, i.t. morphine in an analgesic dose even though smaller than the i.p. dose has a similar inhibitory effect on GI tract motility in the rat. This method would enable comparisons on GI transit to be made between a variety of intrathecally administered drugs.     

Attenuation of exercise induced asthma by local hyperthermia.

BACKGROUND: Prior treatment with local hyperthermia has been shown to prevent mast cell degranulation and leucocyte histamine release, and to reduce mortality and cellular infiltrates in a model of acute lung injury. Local hyperthermia is effective in reducing the symptoms of the common cold and perennial and seasonal allergic rhinitis, nasal patency also being improved in rhinitis. It is possible that these effects are mediated by common anti-inflammatory mechanisms, and that this treatment may be effective in the treatment of asthma. The effect of prior local hyperthermia on the response to exercise challenge and histamine bronchoprovocation was therefore examined. METHODS: In a randomised, double blind, placebo controlled, crossover study, 10 asthmatic subjects with exercise induced asthma used machines delivering 40 1/minute of fully humidified air at either 42 degrees C (active treatment) or 31 degrees C (placebo treatment) for 30 minutes' tidal breathing. For each pretreatment, at two week intervals they underwent exercise challenges starting one and 24 hours after starting the inhalations. After a further two weeks the protocol was repeated with histamine substituted for the exercise challenges. RESULTS: The mean (SE) maximum percentage fall in forced expiratory volume in one second (FEV1) was significantly lower one hour after treatment with air at 42 degrees C (30.8% (3.1%)) than after treatment with air at 31 degrees C (22.3% (2.9%)). There was no significant effect on exercise challenge at 24 hours, or on histamine challenge at either time point, though there were nonsignificant trends towards protection with exercise at 24 hours and with histamine at one hour. CONCLUSION: In asthmatic subjects the response to exercise challenge is significantly attenuated one hour after treatment with local hyperthermia. This treatment warrants further investigation in the treatment of clinical asthma and other inflammatory disorders.     

Effect of fluoride on bone and bone cells in ovariectomized rats.

To evaluate whether treatment with a mitogenic agent may increase bone formation and bone mass in osteopenia induced by estrogen deficiency, we determined the effect of oral fluoride treatment on bone and bone cells in ovariectomized rats. Sodium fluoride (NaF) was administered to 3-month-old ovariectomized rats 1 day after ovariectomy (OVX) for 1, 3, and 6 months. NaF was given in drinking water at the dose of 1 mg/kg body weight per day. Fluoride administration led to a partial prevention of the bone loss induced by OVX as shown by histologic analysis of tibial metaphysis and by evaluation of femoral calcium content. These beneficial effects of fluoride were more striking at early time points (1 and 3 months postovariectomy) than after 6 months of treatment. The increase in trabecular bone volume in OVX rats treated with fluoride was associated with a rise in the osteoblast surface, which was increased by 60, 72, and 235% at 1, 3, and 6 months postovariectomy compared to untreated OVX rats. In OVX rats and in sham-operated rats plasma osteocalcin was increased in correlation with the osteoblast surface. However, these two parameters were not correlated in OVX rats treated with fluoride. The heat-labile bone-specific alkaline phosphatase in plasma was decreased in OVX rats treated with fluoride compared to OVX rats, suggesting that both the number and the activity of osteoblasts were affected by NaF treatment. To examine the effect of fluoride on the osteocalcin production and the proliferative capacity of bone cells, osteoblastic cells were isolated by collagenase digestion from the bone surface of tibia in treated and untreated OVX rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Long term group psychotherapy with (near) psychotic children

Traditionally, psychotherapy groups for children included only relatively intact youngsters. This paper describes a group consisting of four (near) psychotic children and two co-therapists which met for over three years. The developmental changes which occurred in the group over the course of time will be identified and discussed using a neo-psychoanalytic, object relations framework.     

Multiple cutaneous granular cell tumors in childhood

We have described two children with multiple cutaneous granular cell tumors (GCT) and have reviewed the literature. Multiple tumors of the skin are relatively rare, especially in children, with only 18 pediatric cases previously reported. Surgical excision of rapidly growing or symptomatic lesions is the treatment of choice. In these two children with multiple GCT, three lesions were excised. Specific stains for enolase and S-100 protein clearly demarcated tumor margins after surgical excision. Despite intensive investigation, the histogenesis of this tumor is still in dispute. The most tenable theory at this time is that these tumors are derived either directly from Schwann cells or from undifferentiated cells developing neural characteristics.     

A double-blind cross-over study of nifedipine retard in patients with Raynaud's phenomenon

Summary The effectiveness of nifedipine retard as a treatment for Raynaud's phenomenon was assessed in 15 patients in a placebo controlled double blind study. An associated connective tissue disease was evident in 7 patients. Changes in finger and forearm blood flow (venous occlusion plethysmography), digital skin temperature and digital systolic pressure were measured acutely before and after a 2-week treatment period. Subjective assessment of efficacy was based on patient diary data. In addition alpha₂-adrenoceptor density on platelets was measured before and after chronic nifedipine therapy in both the patient group and in an age-and-sex-matched control group. No significant haemodynamic changes were observed. Nifedipine retard significantly reduced the frequency (p<0.05) with no change in either the duration or severity of vasospastic attacks. Side effects were commono following nifedipine retard. A reduction in alpha₂-adrenoceptor density on platelets was observed in patients compared to a control group (p<0.05). Alpha₂-adrenoceptor density was unchanged following a 2-week treatment period with nifedipine retard. This study concludes that nifedipine retard is not effective in the treatment of Raynaud's phenomenon over a short time course. Patients with Raynaud's phenomenon have reduced alpha₂-adrenoceptor densities on their platelets.