Effects of dexamethasone on the differentiation of membrane structure in cultured astrocytes.

Astrocytic processes investing vascular structures or forming the surface of mammalian brain have large numbers of orthogonally packed aggregates of intramembrane particles, termed "assemblies." Similar particle aggregates are expressed by astrocytes derived from neonatal rat forebrain in secondary culture, but they are much more uniformly distributed across the membranes of the cultured cells. Dexamethasone, a potent glucocorticoid, affects the differentiation of astrocyte membrane structure in two patterns, depending on the rate of proliferation in the culture. When confluent secondary cultures of astrocytes are exposed to 5 microM dexamethasone, the densities of assemblies increase, and in some cells approach the values present in the glial limitans in vivo. However, when rapidly proliferating astrocytes are exposed to dexamethasone during the first week of secondary culture, most of the astrocytes fail to express any assemblies. The rate of astrocyte proliferation is slowed, and a lower cell density is reached during the first 2 weeks of secondary culture in dexamethasone. The suppression of assemblies is transient: as the cultures approach confluence, the proportion of cells expressing assemblies increases to nearly control levels, and the density of assemblies increases to greater than control values in some astrocytes. Certain of the effects of dexamethasone on cultured astrocytes may have relevance for understanding the mechanism(s) of its action in treating cerebral edema.     

Embolization with “Ethibloc” of vascular tumors and arteriovenous malformations in the head and neck

Summary Ethibloc has been used almost exclusively until now for embolization of tumors and bleeding vessels in the liver and kidney. Unlike with Gelfoam-particles, there is no recanalization. The resorption occurs so slowly that there is no interference with the necrosis of the embolized tumor. Due to its low viscosity, it passes catheters with thin lumina and fills the capillary bed of the tumor without danger of reaching the venous vessels. In this paper we describe a new technic of percutaneous catheter-embolization with Ethibloc using a coaxial catheter which we believe enhances safety and effectiveness. It has been successfully used in five patients. In the meantime two more patients have been treated successfully.Presented in part at the 17th Annual Meeting of the German Society of Neuroradiology, 9–10 October 1981 in Tübingen, FRG.     

骨科下肢侧卧位手术牵引架的研制及临床应用

目的研制并临床验证一种简便、实用、灵活、科学的骨科下肢侧卧位手术牵引架.方法1999年1月～2003年1月采用本手术设备共进行了51例均在侧卧位状态下进行的手术;其中股骨粗隆间骨折23例、股骨粗隆下骨折4例,行DHS22例、Gamma钉5例;股骨中下段骨折24例,行股骨交锁钉3例、梅花钉3例、LCDCP18例.结果采用本手术设备的手术情况是DHS、Gamma钉组的平均手术时间为51±19min、出血量为100士57ml,交锁钉组的手术时间为70±19min、出血量为312±94ml;与常规的仰卧位手术比较P＜0.01,同时方便C-臂X光机透视,尤其是侧位透视.此外,还可运用本手术设备进行股骨中下段骨折的其他各种内固定手术,牵引效能好,方便术区皮肤消毒及术中骨折复位.结论本骨科下肢侧卧位手术牵引架结构简单、零部件少、装卸容易、适应症广、操作方便、利于C-臂X光机透视,术中出血量少、损伤小、手术时间短,具有较好的实用型、先进性、科学性,值得临床推广应用.     

头颈部坏死性筋膜炎7例临床分析

目的：探讨头颈部坏死性筋膜炎的病因、临床表现、诊断和治疗，加强对这一罕见疾病的认识。方法：回顾分析1992-2002年10年收治的7例头颈部坏死性筋膜炎的病例资料并复习文献。结果：7例全部行积极的内科保守治疗和外科处理（包括局部切开引流、清创术和气管切开术），其中2例死亡。结论：临床上对该病应有足够的认识，以期早期诊断。及时有效的外科处理是治疗成功的关键。     

Fractographic Examination of Racing Greyhound Central (Navicular) Tarsal Bone Failure Surfaces Using Scanning Electron Microscopy

The greyhound is a fatigue fracture model of a short distance running athlete. Greyhounds have a high incidence of central (navicular) tarsal bone (CTB) fractures, which are not associated with overt trauma. We wished to determine whether these fractures occur because of accumulation of fatigue microdamage. We hypothesized that bone from racing dogs would show site-specific microdamage accumulation, causing predisposition to structural failure. We performed a fractographic examination of failure surfaces from fractured bones using scanning electron microscopy and assessed microcracking observed at the failure surface using a visual analog scale. Branching arrays of microcracks were seen in failure surfaces of CTB and adjacent tarsal bones, suggestive of compressive fatigue failure. Branching arrays of microcracks were particularly prevalent in remodeled trabecular bone that had become compact. CTB fractures showed increased microdamage when compared with other in vivo fractures (adjacent tarsal bone and long bone fractures), and ex vivo tarsal fractures induced by monotonic loading (P < 0.02). It was concluded that greyhound racing and training often results in CTB structural failure, because of accumulation and coalescence of branching arrays of fatigue microcracks, the formation of which appears to be predisposed to adapted bone. Received: 12 November 1999 / Accepted: 10 March 2000     

钢的拉伸断口分维测定及应用

本文利用IBAS-2000全自动图像分析系统,运用Slit Island Analysis方法,对40号钢拉伸断口进行了实验室研究。结果表明,钢的热处理制度和拉伸试验温度对断口分维值有重要影响,室温拉伸断口分维数与延伸率呈幂函数关系。     

In vitro T-lymphocyte function in head and neck cancer patients

T-lymphocyte cell function was studied in vitro in peripheral blood mononuclear cells (PBMC) from 61 male patients with head and neck squamous cell carcinomas compared to 46 control patients. Patients older than 80 years or with reduced tumor-related performance status as measured by Karnofsky score less than 75 were excluded. In contrast to previous similar studies, control subjects ensured a minimum stress load by sampling all patients on the day of either diagnostic or therapeutic surgery. PBMC were separated by density-gradient centrifugation and subsequently cultured with autologous sera in vitro. The mitogen concanavalin A (Con A), which stimulates all T-cell clones, was employed. Findings showed that increased Con A stimulation and PBMC proliferation occurred with PBMC from cancer patients compared to that from control patients. In contrast, no differences could be detected with respect to the stimulated supernatant level of interleukin-2, interleukin-4 or interferon-γ between the groups. These results suggest that T-lymphocytes from PBMC are generally affected by neoplastic disease through either a supporting cell or serum factor.     

Palliative care in patients with cancer of the head and neck

Palliative care is the active total care of patients whose disease is not responsive to curative treatment. Patients with end-stage head and neck cancer have particular problems because of the impact of the tumour on the airway, the upper gastrointestinal tract and the major senses. Patients referred for palliative care were identified from the hospice database and the nature, incidence and management of their problems, and the role of the hospice in their care, was reviewed from in-patient and home care notes and patient-generated problem lists. Thirty-two male and six female patients with a median age of 64 years were identified. Locoregional recurrence was present in 79% of patients. Pain, weight loss, feeding difficulties, dysphagia, respiratory symptoms, xerostomia, oral thrush and communication difficulties were the major problems. The management of each, and of the terminal events encountered in the group, is discussed.     

The effect of interleukin-6 on enhancing the invasiveness of head and neck cancer cells in vitro

Patients with head and neck cancers that produce a high concentration of granulocyte colony-stimulating factor (G-CSF) or patients with esophageal squamous cell carcinomas who have elevated serum interleukin-6 (IL-6) concentrations have been found previously to be at significant risk for tumor invasion to adjacent organs as well as frequent metastases. This suggests that G-CSF and Il-6 enhance the invasiveness and metastatic potential of cancer cells. We studied the in vitro invasiveness of head and neck cancer cell lines with and without recombinant human G-CSF (rhG-CSF) and human IL-6 (hIL-6) in an extracellular matrix membrane system. The degree of invasiveness was affected by incubating cells with hIL-6, but not by pre-incubating the cell-matrix with hIL-6. The maximum concentration of hIL-6 for enhanced invasiveness was approximately 5,000 u/ml. In addition, rhG-CSF enhanced the invasiveness of tumor cells that produced large amounts of G-CSF. The present study also suggests that tumor cells tend to invade and metastasize in an environment rich in hIL-6. Received: 3 November 1997 / Accepted: 1 April 1998     

Role of sialoglycan structures for the function of the epidermal growth factor receptor and the in vitro proliferation of head and neck cancer

Squamous cell carcinomas of the head and neck have been found to show a high expression of the receptor for epidermal growth factor (EGF). This overexpression of the receptor has been associated with malignant transformation of cells, although there is still debate as to what extent this receptor takes part in the proliferation of malignant cells and which function it fulfills. The factors which determine receptor-ligand interaction are also not clearly defined. That the extracellular domain of the EGF receptor carries carbohydrate or sialoglycan structures might be important for function of the receptor. Since tumor specific enzymes can possibly alter such structures, it was the aim of our study to investigate the role of these structures on the EGF receptor during the proliferation of head and neck carcinomas. We used the human laryngeal squamous carcinoma cell line HLaC 79 and altered, for the first time, specific glycan structures with sialidase α-2,3 and α-2,6, causing desialylation. Changes were also produced by endo-β-galactosidase and sialyltransferase. Findings were monitored by labeling with bromo-deoxyuridine. To determine receptor affinity, ¹²⁵I-labeled EGF was employed. Results showed that both cell proliferation and receptor affinity depended on the level of sialylation of the receptor carbohydrate side chains. Desialylation led to a statistically significant reduction of tumor cell proliferation to 65 ± 33% (P < 0.01), while receptor affinity decreased to 70 ± 26% (P < 0.01).The importance of EGF receptor for the proliferation of malignant cells seems to depend on the level of sialylation of glycan structures on receptor protein. A release of enzymes by tumor cells may then produce auto-control of tumor proliferation on its own. Received: 5 November 1997 / Accepted: 21 April 1998