Computer-assisted neurosurgery by using a noninvasive vacuum-affixed dental cast that acts as a reference base: another step toward a unified approach in the treatment of brain tumors

OBJECT: The purpose of the study was to evaluate the use of the Vogele-Bale-Hohner (VBH) mouthpiece, which is attached to the patient's upper jaw by negative pressure, for patient-image registration and for tracking the patient's head during image-guided neurosurgery. METHODS: A dynamic reference frame (DRF) is reproducibly mounted on the mouthpiece. Reference points, optimally distributed and attached to the mouthpiece, are used for registration in the patient's absence on the day before surgery. In the operating room, the mouthpiece and DRF are precisely repositioned using a vacuum, and the patient's anatomical structures are automatically registered to corresponding ones on the image. Experimental studies and clinical experiences in 10 patients confirmed repeated (rigid body) localization accuracy in the range of 0 to 2 mm, throughout the entire surgery despite movements by the patient. CONCLUSIONS: Because of its noninvasive, rigid, reliable, and reproducible connection to the patient's head, the VBH vacuum-affixed mouthpiece grants the registration device an accuracy comparable to invasive fiducial markers.     

Ethyl acrylate risk assessment with a hybrid computational fluid dynamics and physiologically based nasal dosimetry model.

Cytotoxicity in the nasal epithelium is frequently observed in rodents exposed to volatile organic acids and esters by inhalation. An interspecies, hybrid computational fluid dynamics and physiologically based pharmacokinetic (CFD-PBPK) dosimetry model for inhaled ethyl acrylate (EA) is available for estimating internal dose measures for EA, its metabolite acrylic acid (AA), and EA-mediated reductions in tissue glutathione (GSH). Nasal tissue concentrations of AA were previously used as the dose metric for a chronic Reference Concentration (RfC) calculation with this compound. However, EA was more toxic than expected, based on calculated tissue AA concentrations. Unlike AA, EA causes depletion of tissue GSH. We have developed an RfC for EA using tissue GSH depletion in the olfactory epithelium as the primary measure of nasal tissue dose. The hybrid CFD-PBPK model was refined to improve the accuracy of simulations for GSH in rat olfactory tissues. This refined model was used to determine the concentration for continuous human exposures to EA predicted to reduce nasal GSH levels to the same extent as seen in rats exposed to EA at the no-observed-effect level (NOEL). Importantly, AA concentrations in the human nasal olfactory epithelium at the proposed chronic RfC were predicted to be lower than the AA concentrations estimated in the rat at the NOEL. Thus, a chronic RfC based on maintaining GSH in the human nasal olfactory epithelium at levels equivalent to the rat NOEL would also provide an adequate margin of safety with respect to AA concentrations in nasal tissues.     

Proportionate mortality among unionized construction ironworkers

This report presents the results of proportionate mortality ratios (PMR) and proportionate cancer mortality ratios (PCMR) among 13,301 members of the International Union of Bridge, Structural, and Ornamental Ironworkers who had been members for a minimum of 1 year, were actively paying dues into the death beneficiary fund, and had died between 1984–1991. Using the United States proportionate mortality rates as the comparison population, statistically significant elevated risks, using 95% confidence intervals (CI), were observed for several types of injuries: falls (N = 259, PMR = 3.57, CI = 3.15–4.03), transportation injuries (N = 363, PMR = 1.22, CI = 1.10–1.35), and other types of injuries (N = 225, PMR = 1.63, CI = 1.43–1.86). The deaths due to falls were significantly elevated for each 10-year age group under age 60 (PMR >7.00) and for those workers with <20 years in the union (PMR >6.00). Elevated mortality risks were also observed for all malignant neoplasms combined (N = 3,682, PMR = 1.09, CI = 1.06–1.13) as well as for site-specific malignant neoplasms of the lung (N = 1,523, PMR = 1.28, CI = 1.21–1.35), pleural mesothelioma (N = 7, PMR = 1.67, CI = 0.67–3.44) and “other and unspecified sites” (N = 307, PMR = 1.29, CI = 1.15–1.44). The category “pneumoconiosis and other respiratory diseases” was also significantly elevated (N = 690, PMR = 1.11, CI = 1.03–1.20); in this category, deaths due to asbestosis had the greatest elevated risk (N = 10, PMR = 3.56, CI = 1.70–6.54). No elevation in risk was found for kidney cancer or for chronic nephritis which were of interest because of Ironworkers' potential exposure to lead. The present study underscores the importance of fall protection and other injury prevention efforts in the construction industry, as well as the need to control airborne exposures to asbestos, welding fumes and other respirable disease hazards. Am. J. Ind. Med. 31:176–187, 1997. © 1997 Wiley-Liss, Inc.     

超声血管造影在肝癌介入治疗前后的应用价值

目的探讨超声血管造影对原发性肝癌（ＨＣＣ）在经皮肤动脉栓塞术（ＴＡＥ）治疗前后的应用价值。方法采用超声造影剂Ｌｅｖｏｖｉｓｔ经肘静脉注入的方法,检查１２例ＨＣＣ患者在ＴＡＥ治疗前后血供的变化情况。要用彩色多普勒血流显像（ＣＤＦＩ）的半定量测量方法,判定栓塞前后肿瘤血供的丰富程度,并与Ｘ线数字减影血管造影（ＤＳＡ）进行对比分析。结果超声血管造影与ＤＳＡ在探查肝癌ＴＡＥ治疗前后肿瘤血供方面无差异（Ｐ〉     

Prefrontal cortical dysfunction in depression determined by Wisconsin Card Sorting Test performance.

OBJECTIVE: Neuroimaging studies have demonstrated reduced prefrontal cortical blood flow and metabolism in depression, but the neurobehavioral significance of these observations is not yet established. METHOD: The Wisconsin Card Sorting Test, a widely used neuropsychological index of prefrontal cortical function, was administered to 79 patients with major depression who had been unmedicated for at least 28 days, to 47 patients with schizophrenia who had never received antipsychotic medication, and to 61 healthy comparison subjects. RESULTS: Depressed patients demonstrated significant deficits on multiple Wisconsin Card Sorting Test measures compared with healthy individuals. These deficits were correlated with the severity of depression and were less severe than those demonstrated by patients with schizophrenia. CONCLUSIONS: These results provide neuropsychological evidence for significant prefrontal cortical dysfunction in depression.     

Phenotypic variation of a new P0 mutation in genetically identical twins

We have identified a new point mutation in the myelin protein zero (P0) gene in two genetically identical twins with a demyelinating neuropathy. The G to A transition at nucleotide position 382 caused an aspartic acid to asparagine substitution in exon 3. Moreover, we found clear clinical differences which were most evident at an early age. These observations suggest that the expression of this P0 mutation may be susceptible to external, non-genetic influences that may act early in the course of the disease to alter the phenotype. Received: 4 August 1998 Received in revised form: 29 October 1998 Accepted: 19 January 1999     

Results and outcome of retroperitoneal lymph node dissection for clinical stage I embryonal carcinoma--predominant testis cancer.

PURPOSE: To determine the incidence of metastatic disease and usage of chemotherapy (adjuvant or metastatic) after primary retroperitoneal lymph node dissection (RPLND) in patients with clinical stage (CS) I embryonal carcinoma (EC)-predominant testicular cancer. EC predominance was defined as the presence of EC at a level greater than that of any other histologic diagnosis. PATIENTS AND METHODS: All CS I patients with nonseminomatous germ cell tumors who underwent RPLND at Indiana University from 1990 to 1995 were reviewed retrospectively. RESULTS: Two-year follow-up was available for 292 of 320 patients. EC-predominant disease was found in 125 (42.8%) of 292. Eighty-five (68.0%) of 125 patients with EC-predominant disease had pathologic stage (PS) I, and 18 (21.2%) of this group of 85 relapsed. A significantly lower PS I relapse rate of 3% was found for patients who had non-EC-predominant disease (P <.0001). PS II disease was more frequent in patients with EC predominance, as 40 (32.0%) of 125 had retroperitoneal metastases, compared with 26 (15.6%) of 167 patients with a non-EC-predominant histologic diagnosis (P =.0024). Chemotherapy was administered to 48 (38.4%) of the 125 patients with CS I EC-predominant disease after RPLND. This included 25 CS I patients with PS II disease who received adjuvant chemotherapy in addition to 23 patients who subsequently required chemotherapy for relapse after RPLND. Ten (66. 6%) of 15 PS II EC-predominant patients were cured by surgery alone. Currently, all 125 EC-predominant patients are disease-free. CONCLUSION: Patients with CS I EC-predominant disease are at a relatively high risk for metastatic disease.     

Interpretations and variations of ISO 9000 in acute health care. International Organization for Standardization.

OBJECTIVE: This paper aims to address two questions related to the implementation of the ISO 9000 Quality Management System standard in the acute health care sector: which countries have developed specific nationwide guidelines/interpretations? and what variances exist between the different interpretations of the ISO 9002 standard? DESIGN: The study was carried out via an assessment of the available guideline documents for the use of ISO 9000 in the acute health care sector. The interpretation of each document was examined for common elements and deviations from the commonly agreed terms. SETTING: Worldwide in the acute health care sector (excluding that of laboratories). STUDY PARTICIPANTS: Eighty-two international ISO members and/or quality health care organizations. RESULTS: The results showed variation in the interpretations of the ISO 9000 standard. In total, 16 of the clauses/subclauses note distinct variations, between one or more of the documents, which could alter the perception of the system. CONCLUSION: From examination of the six identified guideline documents, the claim that ISO 9000 introduces quality systems which are comparable from one country to another is unfounded in the acute health care sector.     

End‐Group Selectivity of Low‐Molecular‐Weight Polystyrenes on a Carbon‐Clad Zirconia Stationary Phase in Reversed‐Phase HPLC

The separation of isomers of polystyrene oligomers was demonstrated on a carbon‐clad zirconia stationary phase in an acetonitrile mobile phase. The carbon‐clad zirconia surface gave considerably better resolution of isomers than a C18 surface, and the separation was sensitive to the end group of the oligomer. Oligomers with sec‐butyl end groups displayed almost twice as many isomers as the corresponding n‐butyl oligomer on the carbon‐clad zirconia surface. These additional bands could be explained by the stereochemistry of the sec‐butyl end group. In addition, the migration rate of the polystyrene isomers was dependent upon the end group, with n‐butyl polystyrenes displaying significantly greater retention on the carbon‐clad zirconia stationary phase. In comparison, the selectivity of conventional C18 columns could not discriminate between the n‐butyl and sec‐butyl end groups.