A two pathway model for tonic suppressed-by-contrast cells in the cat retina

A two pathway spatiotemporal model is proposed to describe the function of tonic suppressed-by-contrast cells of the cat retina. The model is able to describe the experimentally determined responses of such neurons to drifting sinusoidal gratings. It is also able to predict their responses to alternating sinusoidal gratings and flashing or moving spots of light, and these predictions resemble experimental observations, at least qualitatively. The model is physiologically plausible, it can be used to summarize the dynamic responses of the tonic suppressed-by-contrast cells of the cat and potentially to account for the responses of the suppressed-by-contrast cells of other species.     

Analysis of risk factors for distant metastases in squamous cell carcinoma of the oral cavity

BACKGROUND: The number of patients with oral cavity squamous cell carcinoma (OSCC) is increasing. Because the characteristics of patients with OSCC who develop distant metastases (DM) remain uncertain, the authors analyzed potential risk factors. METHODS: For this report, the authors retrospectively reviewed data from 889 consecutive patients with OSCC who underwent radical surgery from January 1996 to November 2004. Patients were divided into 2 groups according to whether they had either achieved locoregional control (Group A; n = 678 patients) or developed a locoregional recurrence (Group B; n = 211 patients). Cox proportional-hazards models were used to identify independent predictors of the 5-year DM rate. RESULTS: In the entire study cohort, the 5-year DM rate was 9.6% (6.6% for Group A and 21.4% for Group B). In Group A, the number of positive lymph nodes (> or =5; P = .009) and the presence of extracapsular spread (ECS) (P < .001) were independent risk factors for DM. In Group B, the presence of ECS (P = .008), poor differentiation (P = .040), pathological stage > or =III (P = .036), and the presence of neck recurrence (P = .001) were independent prognosticators. CONCLUSIONS: The current results indicated that different risk factor categories according to locoregional control may be used to facilitate the selection of appropriate management for patients with OSCC after they undergo radical surgery.     

Evaluation of spatial resolution of a PET scanner through the simulation and experimental measurement of the recovery coefficient

Purpose: In order to measure spatial resolution of a PET tomograph in clinical conditions, this study describes and validates a method based on the recovery coefficient, a factor required to compensate underestimation in measured radioactivity concentration for small structures.Methods: In a PET image, the recovery factors of radioactive spheres were measured and their comparison with simulated recovery coefficients yielded the tomographic spatial resolution. Following this methodology, resolution was determined in different surrounding media and several conditions for reconstruction, including clinical conditions for brain PET studies. All spatial resolution values were compared with those obtained using classical methods with point and line sources.Results: In each considered condition, spatial resolution of the PET image estimated using the recovery coefficient showed good agreement with classical methods measurements, validating the procedure.Conclusion: Measurement of the recovery coefficient provides an assessment of tomographic spatial resolution, particularly in clinical studies conditions.     

Pathogenesis of equine herpesvirus‐1 infection in the mouse model

Equine herpesvirus‐1 (EHV‐1) is a major equine pathogen causing respiratory diseases, abortions and severe neurological disorders. The basis of neurological disturbances is, as in other organs, infection of endothelial cells, followed by vasculitis, thrombosis and ischaemic damage of the parenchyma. Here, a murine model was used to explore the mechanism of entry to, and spread within the brain, the cell affinity of the agent and the modulating role of the immune defence, which are all factors governing the pathogenesis of the neurological disease. Because controversial views exist about these mechanisms, we undertook a neuropathological study with intranasally infected adult mice. EHV‐1 entered the brain through the olfactory neuroepithelium and along the olfactory nerves, and spread transsynaptically in rostro‐caudal direction, using olfactory and limbic neuronal networks. Exclusively neurons were infected. The cellular immune reaction exerted a restraining effect on virus dissemination. Following nasal infection, the olfactory route was the major pathway for virus entry and dissemination, involvement of the trigeminal nerve in virus spread seems much less probable. In the adult mouse brain EHV‐1 behaves as a typical neurotropic agent, using, similarly to other herpesviruses, the neuronal networks for dissemination. Vasculitis, the predominant type of lesion in natural infection, and endothelial cell positivity for EHV‐1 were detectable only in the lung. Thus, this agent exhibits in the mouse a dual affinity: it is neurotropic in the brain, and endotheliotropic in visceral organs. Consideration of pathogenetic aspects of equine and experimental murine EHV‐1 infections also helps a better understanding of human herpetic brain disease.     

豚草在中国的蔓延及治理措施

豚草是一种外来入侵的有害植物,自20世纪30年代传入中国,根据气传花粉调查、野外考察资料发现,豚草已蔓延到我国12个省的30多个城市。豚草花粉已成为我国过敏性鼻炎和支气管哮喘的重要病因之一。此外,豚草破坏生态环境,对农牧业造成严重危害并带来巨大的经济损失。因此,必须采取有效的防除措施。进入21世纪后,豚草在中国的蔓延及治理措施如何,本文对此进行综述。     

Fine needle aspiration biopsy proves increased T-lymphocyte proliferation in tumor and decreased metastatic infiltration after treatment with doxorubicin bound to PHPMA copolymer carrier

Abstract

Introduction: Fine needle aspiration biopsy (FNAB) is an easy method with an option of repetitive withdrawal of cell material.

Methods: First, mice were inoculated with mouse T-lymphoma, after 10?d the samples from tumor, lymph nodes and spleen gained by FNAB and excision were analyzed by flow cytometry. Tumor progression was compared to the control group simultaneously. Then, 10?d after tumor cell inoculation free doxorubicin (DOX) or different PHPMA DOX conjugates were injected. Cell material was analyzed to detect subpopulations of lymphocyte infiltrate, and levels of cytokines in correlation with progression or regression of the disease.

Results: FNAB has no influence on the tumor’s growth or survival of experimental animals. After treatment with PHPMA conjugates there was a significant increase of T-lymphocyte subpopulations in tumor microenvironment compared to controls or free DOX, but only in mice with confirmed macroscopic regression of tumor within two weeks. Mice treated with conjugates showed significantly lower cancer infiltration of lymph nodes and spleen.

Conclusion: FNAB provides a great benefit to in vivo monitoring of cell changes directly in the tumor after treatment. The number of infiltrating T-lymphocytes increases in correlation with consecutive tumor eradication after treatment with PHPMA. This proves that not only direct cytotoxic but also imunostimulating effect are necessary for successful treatment.     

Pilocytic Astrocytoma with subarachnoidal spread

Summary Pilocytic Astrocytomas (WHO I) are histopathologically tumors of glial origin occurring predominantly in childhood and adolescence. Normally, they are characterized by a benign clinical course, with a long overall survival time and a high rate of complete remission. The rare case of pilocytic astrocytoma, primarily located in the third ventricular region, with generalized subarachnoidal spread is described. In the 10 years of follow-up, the histopathologic findings of the seedings remained those of a typical pilocytic astrocytoma; tumor progression did not occur.      

视网膜母细胞瘤细胞分化及扩散与预后关系的调查分析

目的：研究视网膜母细胞瘤（ｒｅｔｉｎｏｂｌａｓｔｏｍａ，ＲＢ）细胞分化程度及肿瘤扩散与预后的关系。方法：对８２例摘除眼球的ＲＢ病人临床、随访资料和病理标本进行调查研究，比较分化型与未分化型ＲＢ术后的病死率，不同扩散部位的病死率。记录死者术后存活时间及生存者的后遗症。结果：分化型ＲＢ病死率２７．２７％，未分化型为２２．５４％，眶内和巩膜侵犯病死率１００％，视神经侵犯Ⅳ级病死率６２．５％，葡萄膜侵犯病死率２２．２２％。死者术后平均生存时间２１．９２月。存活者主要存在面部整形问题。结论：ＲＢ预后与肿瘤细胞分化程度无明显关系，发生扩散的ＲＢ病人如能适当治疗，可提高生存率