Lung counting: a function to fit counting efficiency of a lung counting germanium detector array to muscle-equivalent-chest-wall-thickness and photon energy using a realistic torso phantom

A function has been developed that will fit counting efficiency to chest wall thickness, adipose content of the chest wall, and photon energy. The adipose content of the chest wall is removed as a variable by use of the derived quantity: muscle equivalent chest wall thickness. The function has been tested on experimental data sets obtained from the LLNL and JAERI torso phantoms using a variety of germanium detector lung counting systems. The function is applicable over the range of existing phantoms and the range of equipment types tested. Subtle differences between the detector systems are shown by differences in the fit parameters. This analysis could be a useful addition to lung counting analysis software. The LLNL and JAERI phantoms have very similar counting characteristics as evidenced by the similarity of the function parameters when measured using a single detector system.     

Error-related processing during a period of extended wakefulness

The nature of error detection as manifested by the error-related negativity was examined in both a Sternberg memory search task and a visual search task. Both tasks were performed in conditions with consistent or varied stimulus-response mapping and loads of three or six letters. After subjects were trained extensively in all conditions, they performed the tasks throughout the night without sleeping. The data suggest that the effectiveness of error detection decreases over time because of a decrease in the quality of perceptual processing. Error detection also suffers when performance requires more search-related resources. In both cases, the representation of the correct response is compromised. These results indicate that error detection depends on the same perceptual and cognitive processes that are required for correct performance.     

Magnetic resonance angiography of primary varicella vasculitis: report of two cases

Two patients with onset of hemiparesis 3 weeks following primary varicella infection demonstrated contralateral temporal lobe and basal ganglia infarctions on magnetic resonance imaging. In both cases, magnetic resonance angiography (MRA) was performed and demonstrated flow abnormalities ipsilateral to the infarcts. Digital subtraction angiography was performed in one case; however, the findings were significantly less conspicuous than those of the MRA. MRA proved to be sensitive to the diagnosis of varicella-induced vasculitis in two consecutive cases and provided a noninvasive means of following the progression of the disease process in response to therapy.     

Phospholipase A2 enzymes regulate alpha IIb beta3-mediated, but not Fc gammaRII receptor-mediated, pp125FAK phosphorylation in platelets

The alphaII(b)beta3 integrin and FcgammaRII receptors mediate, respectively, platelet adhesion and spreading on fibrinogen and immunoglobulin (IgG) coated surfaces. Platelet adhesion to fibrinogen resulted in a partial conversion of the faster to the slower migrating (phosphorylated) form of Ca(+2)-sensitive cytosolic phospholipase A2(cPLA2) but failed to trigger arachidonic acid (AA) release. Full mobility shift of cPLA2 and a massive release of AA release were stimulated by platelet adhesion to IgG or addition of thrombin to the fibrinogen adherent platelets. IgG and thrombin induced AA production were blocked by methyl arachidonyl fluorophosphonate (MAFP), an irreversible inhibitor of cPLA2 and the Ca(+2)-independent phospholipase A2 (iPLA2). In contrast, bromoenol lactone (BEL), a specific inhibitor of iPLA2 had no effect on the release of AA. MAFP and BEL prevented pp125FAK phosphorylation and platelet spreading on fibrinogen having no effect on pp125FAK phosphorylation or platelet spreading on immobilized IgG. We conclude that alpha(IIb)beta3-mediated pp125FAK phosphorylation and platelet spreading on fibrinogen are regulated by PLA2 enzymes.     

Surgical-site complications associated with a morphine nerve paste used for postoperative pain control after laminectomy.

OBJECTIVE: To identify risk factors that might explain a sudden increase in the rate of surgical-site complications following laminectomy. DESIGN: Retrospective cohort study. PATIENTS AND SETTING: Patients who underwent laminectomy at a 120-bed hospital from August 1 through October 15, 1996 (the epidemic period). A case-patient was defined as a patient with postoperative surgical-site complications (surgical-site drainage, edema, or swelling) requiring surgical debridement. RESULTS: Of the 148 patients who underwent a laminectomy during the epidemic period, 17 (11%) met our case definition. The rate of postoperative surgical debridement was 7.6-fold higher during the epidemic period than the preceding 19-month period (17/148 vs 15/995, P<.001). Development of surgical-site complications was associated with intraoperative receipt of morphine nerve paste (relative risk [RR], 11; P<.001), preoperative shaving by nurses rather than surgeons (RR, 6.6; P=.006), procedures done by a certain surgeon (RR, 3.1; P=.022), or receipt of iodine rather than povidone-iodine for preoperative skin antisepsis (RR, 5.1; P=.002). In multivariate analysis, only receipt of morphine nerve paste remained as a risk factor (RR, 18; P=.011). The paste was used to control postoperative pain and was applied directly to exposed dura and surrounding tissues. At the time of surgical debridement (median, 24 days postsurgery), the original surgical sites showed residual paste and a lack of healing. Ten of 16 cultures from surgical sites were positive; all but three grew skin commensals. Histological examination of surgical specimens showed a foreign-body reaction, but no marked acute inflammation. CONCLUSIONS: The intraoperative use of morphine nerve paste may delay wound healing and increase postoperative morbidity. When new products are introduced, standardized protocols should be developed for their use, and systematic surveillance should be done to monitor for potential adverse outcomes.     

Effects of photodynamic therapy using verteporfin on experimental choroidal neovascularization and normal retina and choroid up to 7 weeks after treatment.

PURPOSE: To study the long-term effects of photodynamic therapy (PDT), using liposomal benzoporphyrin derivative (BPD) or Verteporfin, on experimental choroidal neovascularization (CNV) and on normal retina and choroid (with no CNV) in the cynomolgus monkey eye. METHODS: Photodynamic therapy was performed in 8 cynomolgus monkey eyes with experimental CNV induced by laser injury. The effect of PDT on normal retina and choroid (with no CNV) was studied in 9 monkey eyes. Liposomal BPD was administered intravenously (0.375 mg/kg) either as a bolus, as a slow infusion over 32 minutes, or as a fast infusion over 10 minutes. Photodynamic therapy was performed using light at a wavelength of 689 or 692 nm, with an irradiance of 600 mW/cm2 and fluence of 150 J/cm2. Follow-up studies, including fundus photography and FA, were performed at 24 hours after PDT and then weekly. Indocyanine green and BPD angiography were performed in selected cases. Tissues were examined with light and electron microscopy at the end of follow-up. RESULTS: Twenty-three of the 32 areas of CNV treated with PDT showed absence of angiographic leakage at 24 hours. Twenty-eight areas of CNV were followed for 4 weeks; 22 of 28 showed absence of angiographic leakage at 2 weeks; and 20 of 28 at 4 weeks of follow-up. Forty spots on the normal retina and choroid were treated with PDT and were followed for 4 to 7 weeks. These spots showed pigment-laden cells in the outer retina, variably pigmented retinal pigment epithelium (RPE) in the treated area, intact neurosensory retina, and reperfusion of the choriocapillaris. CONCLUSIONS: Photodynamic therapy leads to absence of angiographic leakage for at least 4 weeks in experimental CNV in the monkey model. In the normal monkey eye the RPE and choriocapillaris show generalized recovery with preservation of the neurosensory retina 7 weeks after PDT.     

Physicians who keep lax records put careers in danger, college course warns.

During a recent workshop sponsored by the College of Physicians and Surgeons of Ontario, Dr. Paul Caulford identified the most common problems with medical records: they are much too brief, don't tell the patient's story and are missing important details. He warned that physicians must pay more attention to their records because "the way things are moving, the scrutiny of records in the past in nothing in comparison to what it will be like in the future."     

Actigraphically recorded motor activity and immobility across sleep cycles and stages in healthy male subjects

The aim of this study was to compare the extent to which activity and immobility measures are related to sleep stages and sleep cycles in order to improve the informative value of actigraphic assessment of sleep. We therefore performed simultaneous ambulatory polysomnography and wrist-activity monitoring (AM) in 14 healthy male subjects without sleep complaints. In this context, a simple method for transforming raw motor activity data into a time-series reflecting onset and duration of activity and immobility clusters is introduced. Our results demonstrate that nocturnal AM measures were significantly affected by sleep stage. Low activity levels and particularly prolonged episodes of uninterrupted immobility were associated with increasing sleep depth. On the other hand, high activity levels and prolonged episodes of activity were related to intermittent wakefulness during sleep. Our results suggest that measures reflecting the occurrence and duration of activity and immobility clusters provide a better approach in studying the relationship between activity/immobility and sleep stages. Except for the duration of uninterrupted immobility episodes, which showed a significant decrease in the fourth cycle, none of the AM measures showed a significant cycle-to-cycle variation. Consequently, mean nocturnal motor activity measures provide an accurate reflection of the total sleep period. However, none of the AM-derived measures seems useful in evaluating the cycle structure during sleep.     

306. Martin Kirschner zum 100. Geburtstag

Zusammenfassung Kirschner wurde 1879 in Breslau geboren. 1916 erhielt er den Ruf auf den Lehrstuhl in Königsberg, 1927 nach TÜbingen und 1934 nach Heidelberg. An diesen Stätten erbaute er neue Kliniken. Erfolgreich arbeitete er auf allen chirurgischen Teilgebieten. Besonders erwähnenswert seien die erste erfolgreiche pulmonale Embolektomie, die einzeitige Lungenlappenresektion, ein neues Verfahren in der Oesophaguschirurgie, die EinfÜhrung des halbstarren Kirschner-Drahtes, in der Schmerzbekämpfung die Avertinnarkose, die Spinalanaesthesie und die Elektrocoagulation des Ganglion Gasseri. 1932 begrÜndete er die heute von Zenker fortgefÜhrte Operationslehre.