Rapid Increase in Neural Conduction Time in the Adult Human Auditory Brainstem Following Sudden Unilateral Deafness

Individuals with sudden unilateral deafness offer a unique opportunity to study plasticity of the binaural auditory system in adult humans. Stimulation of the intact ear results in increased activity in the auditory cortex. However, there are no reports of changes at sub-cortical levels in humans. Therefore, the aim of the present study was to investigate changes in sub-cortical activity immediately before and after the onset of surgically induced unilateral deafness in adult humans. Click-evoked auditory brainstem responses (ABRs) to stimulation of the healthy ear were recorded from ten adults during the course of translabyrinthine surgery for the removal of a unilateral acoustic neuroma. This surgical technique always results in abrupt deafferentation of the affected ear. The results revealed a rapid (within minutes) reduction in latency of wave V (mean pre = 6.55 ms; mean post = 6.15 ms; p < 0.001). A latency reduction was also observed for wave III (mean pre = 4.40 ms; mean post = 4.13 ms; p < 0.001). These reductions in response latency are consistent with functional changes including disinhibition or/and more rapid intra-cellular signalling affecting binaurally sensitive neurons in the central auditory system. The results are highly relevant for improved understanding of putative physiological mechanisms underlying perceptual disorders such as tinnitus and hyperacusis.     

Changes in glial fibrillary acidic protein mRNA expression after corticospinal axotomy in the adult hamster

We examined changes in the expression of glial fibrillary acidic protein (GFAP) mRNA during Wallerian degeneration in the corticospinal system of the adult Golden hamster following axotomy. GFAP is the product of a type III intermediate filament (IF) gene that is expressed specifically in mature astrocytes. A well-studied component of a complex response termed reactive astrogliosis that occurs after various types of CNS injury is the increased production of astrocytic processes filled with GFAP-containing IFs. While increased expression of GFAP during reactive astrogliosis has been well established at the protein level, little is known about whether or not changes in GFAP mRNA levels occur after CNS injury. In the present study we used in situ hybridization methods to examine this issue. A 35S-labeled mouse GFAP cDNA probe was used for in situ hybridizations of sections of the brain stem obtained 2, 7, and 14 days after unilateral transections of the corticospinal tract in the caudal medulla. Film as well as emulsion autoradiography showed a dramatic increase in GFAP mRNA labeling associated with the degenerating corticospinal tract. GFAP mRNA levels were already dramatically increased in the injured corticospinal tract by 2 days post axotomy and remained elevated at 14 days. Interestingly, in addition to the robust increase in GFAP mRNA levels specifically associated with the degenerating tract, a diffuse increase in GFAP mRNA labeling was observed throughout the grey matter of the brain stem at 2 days post-axotomy, but not after this time. Immunoblotting and immunocytochemical experiments verified that the increased GFAP mRNA levels in the degenerating corticospinal system were accompanied by an increased expression of the protein. These results demonstrate that an increase in GFAP mRNA levels occurs during Wallerian degeneration in the CNS and suggest that increased expression of the GFAP gene is a major contributor to CNS scarring that results after direct traumatic injury.     

Entrapment of pacemaker lead by a large netlike Eustachian valve within the right atrium

Summary During pacemaker implantation in a patient with permanent atrial fibrillation, it remained impossible to advance a passive fixation lead with fins through the right atrium. However, a lead with a retractable screw easily passed the right atrium and was positioned in the right ventricle. Transesophageal echocardiography revealed an extensive net–like perforated Eustachian valve within the right atrium that had caused entrapment of the anchor fins during lead implantation. Remnants of embryonal structures within the right atrium should be considered a rare possible barrier during pacemaker implantation.     

无线网络技术在医学仪器中的应用

简要介绍无线网络技术的原理、特点及其在医学仪器中的应用.     

两出口的医院网络用户管理解决方案

目的：由于办公需要，将以前走电信出口的图书馆、医疗二系及研究生处的用户改道为走科研教育网出口，和华中科技大学校总部相连，并在不改变原来管理模式下同时管理两出口的用户信息。方法：通过配置流分类，规定重定向行为以及配置策略路由进行实现。结果：将认证流和数据流分开，成功实现了医院内部两出口的需求。结论：利用原有设备的流分类和重定向功能．既可解决两出口的内部需求，也能在不增加设备的情况下对用户信息进行管理，为医院节省了开支。     

The UK Diabetes Research Network--an opportunity and a challenge.

The Department of Health has funded a national diabetes network to support clinical research. The network will facilitate recruitment into clinical trials and has been widely welcomed by clinicians. However, if the network is to reach its full potential, all those involved will need to advocate a change in attitude towards clinical trials and research, encouraging participation and contribution of data. Clinicians need to be willing to take a proactive view about research studies, and to encourage patients to adopt a positive and altruistic attitude towards trial participation. The future of trials and other important clinical research in the UK may depend on it.     

A phase I/II study of continuous infusion suramin in patients with hormone-refractory prostate cancer : toxicity and response

 Introduction: Suramin is a synthetic polysulfonated naphthylurea which has been used for the treatment of African trypanosomiasis and onchocerciasis, but since the mid-1980s has received attention as a possible antiretroviral and antineoplastic agent. Objective: This clinical trial of suramin was undertaken as a phase I/II study in patients with hormone-refractory prostate cancer, with the hypothesis that the intensity of therapy with suramin could be increased significantly if measures were undertaken to maintain the plasma concentrations of the drug under 300 μg/ml. Methods: We report the clinical results of this trial, wherein patients were treated at three different targeted plasma suramin concentrations (275, 215 and 175 μg/ml) for varying periods of time (2, 4 or 8 weeks), with delivery of the drug by continuous intravenous infusion. Results: The major toxicity observed in this trial was neurologic, consisting of a motor and sensory peripheral neuropathy that resulted in both paresis and paralysis of the limbs. Nearly all of this severe (CTEP grade III, IV) neurologic toxicity was observed in the patients treated at a plasma suramin concentration of 275 μg/ml for 4 or more weeks. A single patient treated at 215 μg/ml for 8 weeks developed moderate (CTEP grade III) proximal lower extremity weakness, and no patient treated at 175 μg/ml developed this toxicity. The second most common toxicity observed was infection of the central venous catheter. The overall response rate for all of the evaluable patients was 17% (13 of 75 patients). In addition, prostate-specific antigen (PSA)-defined responses were observed in six patients receiving therapy at 175 μg/ml, but these responses were confounded by cessation of therapy with flutamide during suramin treatment. Conclusions: In summary, although plasma suramin concentrations were maintained below 300 μg/ml, neurologic toxicity nonetheless occurred with high frequency in patients treated at 275 μg/ml for 4 or more weeks. Therapy at 215 and 175 μg/ml was in general well tolerated, but central venous catheter-related infection, as well as the inconvenience and expense of continuous infusional therapy, make this method of drug delivery impractical. Only moderate antitumor activity was observed during this trial, but it is possible that both continuation of flutamide and flutamide withdrawal during suramin therapy confounded the assessment of suramin’s activity in hormone-refractory prostate cancer. Received: 9 June 1995/Accepted: 18 March 1996