The British freshwater Rhizopoda and Heliozoa / by James Cash, assisted by John Hopkinson.

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A course of practical instruction in elementary biology, by T. H. Huxley, assisted by H. N. Martin.

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Computer-assisted motion compensation and analysis of perfusion ultrasound data

Magdeburg, Univ., Fak. für Informatik, Diss., 2014

PulseCath iVAC 3LTM hemodynamic performance for simple assisted flow.

The PulseCath iVAC 3L? left ventricular assist device is an option to treat transitory left heart failure or dysfunction post-cardiac surgery. Assisted blood flow should reach up to 3 l/min. In the present in vitro model exact pump flow, depending on various frequencies and afterload was examined. Optimal flow was achieved with inflation/deflation frequencies of about 70-80/min. The maximal flow rate was achieved at about 2.5 l/min with a minimal afterload of 22 mmHg. Handling of the device was easy due to the connection to a standard intra-aortic balloon pump console. With increasing afterload (up to a simulated mean systemic pressure of 66 mmHg) flow rate and cardiac support are in some extent limited.

Non-assisted versus neuro-navigated and XperCT-guided external ventricular catheter placement: a comparative cadaver study.

BACKGROUND AND PURPOSE: Accurate placement of an external ventricular drain (EVD) for the treatment of hydrocephalus is of paramount importance for its functionality and in order to minimize morbidity and complications. The aim of this study was to compare two different drain insertion assistance tools with the traditional free-hand anatomical landmark method, and to measure efficacy, safety and precision. METHODS: Ten cadaver heads were prepared by opening large bone windows centered on Kocher's points on both sides. Nineteen physicians, divided in two groups (trainees and board certified neurosurgeons) performed EVD insertions. The target for the ventricular drain tip was the ipsilateral foramen of Monro. Each participant inserted the external ventricular catheter in three different ways: 1) free-hand by anatomical landmarks, 2) neuronavigation-assisted (NN), and 3) XperCT-guided (XCT). The number of ventricular hits and dangerous trajectories; time to proceed; radiation exposure of patients and physicians; distance of the catheter tip to target and size of deviations projected in the orthogonal plans were measured and compared. RESULTS: Insertion using XCT increased the probability of ventricular puncture from 69.2 to 90.2 % (p = 0.02). Non-assisted placements were significantly less precise (catheter tip to target distance 14.3 ± 7.4 mm versus 9.6 ± 7.2 mm, p = 0.0003). The insertion time to proceed increased from 3.04 ± 2.06 min. to 7.3 ± 3.6 min. (p < 0.001). The X-ray exposure for XCT was 32.23 mSv, but could be reduced to 13.9 mSv if patients were initially imaged in the hybrid-operating suite. No supplementary radiation exposure is needed for NN if patients are imaged according to a navigation protocol initially. CONCLUSION: This ex vivo study demonstrates a significantly improved accuracy and safety using either NN or XCT-assisted methods. Therefore, efforts should be undertaken to implement these new technologies into daily clinical practice. However, the accuracy versus urgency of an EVD placement has to be balanced, as the image-guided insertion technique will implicate a longer preparation time due to a specific image acquisition and trajectory planning.

Relay-assisted transmission and radio resource management for wireless networks

The following paper presents an overview of the Ph.D Thesis1 presented in [1], which compiles all the research done during the period of time between 2004-2007. In that dissertation the relay-assisted transmission with half-duplex relays is analyzed from different points of view. This study is motivated by the necessity of finding innovative solutions to cope with the requirements of next generation wireless services, and with current radio technology. The use of relayed communications represents a change of paradigm of conventional communications, and requires the definition and evaluation of protocols to be applied to single or multiple-user relay communication. With the two fold goal of enhancing spectral efficiency and homogenize service in cellular communications, system design is investigated at physical (type of transmissions of the relay, decoding mode, ..) and upper layers (resource allocation, dynamic link control).

Results of computer assisted navigation in Total Knee Arthroplasty (TKA): comparison with the conventional method

The aim of this retrospective study was to compare the clinical and radiographic results after TKA (PFC, DePuy), performed either by computer assisted navigation (CAS, Brainlab, Johnson&Johnson) or by conventional means. Material and methods: Between May and December 2006 we reviewed 36 conventional TKA performed between 2002 and 2003 (group A) and 37 navigated TKA performed between 2005 and 2006 (group B) by the same experienced surgeon. The mean age in group A was 74 years (range 62-90) and 73 (range 58-85) in group B with a similar age distribution. The preoperative mechanical axes in group A ranged from -13° varus to +13° valgus (mean absolute deviation 6.83°, SD 3.86), in group B from -13° to +16° (mean absolute deviation 5.35, SD 4.29). Patients with a previous tibial osteotomy or revision arthroplasty were excluded from the study. Examination was done by an experienced orthopedic resident independent of the surgeon. All patients had pre- and postoperative long standing radiographs. The IKSS and the WOMAC were utilized to determine the clinical outcome. Patient's degree of satisfaction was assessed on a visual analogous scale (VAS). Results: 32 of the 37 navigated TKAs (86,5%) showed a postoperative mechanical axis within the limits of 3 degrees of valgus or varus deviation compared to only 24 (66%) of the 36 standard TKAs. This difference was significant (p = 0.045). The mean absolute deviation from neutral axis was 3.00° (range -5° to +9°, SD: 1.75) in group A in comparison to 1.54° (range -5° to +4°, SD: 1.41) in group B with a highly significant difference (p = 0.000). Furthermore, both groups showed a significant postoperative improvement of their mean IKSS-values (group A: 89 preoperative to 169 postoperative, group B 88 to 176) without a significant difference between the two groups. Neither the WOMAC nor the patient's degree of satisfaction - as assessed by VAS - showed significant differences. Operation time was significantly higher in group B (mean 119.9 min.) than in group A (mean 99.6 min., p <0.000). Conclusion: Our study showed consistent significant improvement of postoperative frontal alignment in TKA by computer assisted navigation (CAS) compared to standard methods, even in the hands of a surgeon well experienced in standard TKA implantation. However, the follow-up time of this study was not long enough to judge differences in clinical outcome. Thus, the relevance of computer navigation for clinical outcome and survival of TKA remains to be proved in long term studies to justify the longer operation time. References 1 Stulberg SD. Clin Orth Rel Res. 2003;(416):177-84. 2 Chauhan SK. JBJS Br. 2004;86(3):372-7. 3 Bäthis H, et al. Orthopäde. 2006;35(10):1056-65.

Performance of matrix-assisted laser desorption ionization-time of flight mass spectrometry for identification of bacterial strains routinely isolated in a clinical microbiology laboratory.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has recently been introduced in diagnostic microbiology laboratories for the identification of bacterial and yeast strains isolated from clinical samples. In the present study, we prospectively compared MALDI-TOF MS to the conventional phenotypic method for the identification of routine isolates. Colonies were analyzed by MALDI-TOF MS either by direct deposition on the target plate or after a formic acid-acetonitrile extraction step if no valid result was initially obtained. Among 1,371 isolates identified by conventional methods, 1,278 (93.2%) were putatively identified to the species level by MALDI-TOF MS and 73 (5.3%) were identified to the genus level, but no reliable identification was obtained for 20 (1.5%). Among the 1,278 isolates identified to the species level by MALDI-TOF MS, 63 (4.9%) discordant results were initially identified. Most discordant results (42/63) were due to systematic database-related taxonomical differences, 14 were explained by poor discrimination of the MALDI-TOF MS spectra obtained, and 7 were due to errors in the initial conventional identification. An extraction step was required to obtain a valid MALDI-TOF MS identification for 25.6% of the 1,278 valid isolates. In conclusion, our results show that MALDI-TOF MS is a fast and reliable technique which has the potential to replace conventional phenotypic identification for most bacterial strains routinely isolated in clinical microbiology laboratories.

Handheld-assisted field data collection for occupational risk assessment.

A computerized handheld procedure is presented in this paper. It is intended as a database complementary tool, to enhance prospective risk analysis in the field of occupational health. The Pendragon forms software (version 3.2) has been used to implement acquisition procedures on Personal Digital Assistants (PDAs) and to transfer data to a computer in an MS-Access format. The data acquisition strategy proposed relies on the risk assessment method practiced at the Institute of Occupational Health Sciences (IST). It involves the use of a systematic hazard list and semi-quantitative risk assessment scales. A set of 7 modular forms has been developed to cover the basic need of field audits. Despite the minor drawbacks observed, the results obtained so far show that handhelds are adequate to support field risk assessment and follow-up activities. Further improvements must still be made in order to increase the tool effectiveness and field adequacy.

Endoscopic mucosal resection in the esophagus with a new rigide device : an animal study

Résumé: Introduction : L'utilisation de méthodes endoscopiques peu invasives est en constante augmentation pour le traitement des lésions tumorales précoces de l'oesophage. Le but du traitement comprend l'éradication complète de tous les foyers de dysplasie ou de carcinome in situ, notamment dans les métaplasies intestinales de l'oesophage de Barrett, qui peuvent dégénérer en adénocarcinome. Plusieurs techniques d'ablation de la muqueuse oesophagienne (laser, argon plasma, electrocoagulation, photothérapie dynamique, résection endoscopique) ont été utilisées jusqu'à présent, mais aucune n'a vraiment donné entière satisfaction. Les techniques actuelles de résections endoscopiques par fibroscopie sont entre autres limitées par le grand nombre de séances nécessaires à l'éradication complète de la lésion et par la petite taille des fragments de muqueuse obtenus, ce qui rend l'analyse histologique difficile. Dans notre étude animale, nous avons évalué la faisabilité, l'efficacité et la sécurité d'une méthode de résection endoscopique à l'aide d'un nouvel oesophagoscope rigide. Matériel et méthode : Le résectoscope est formé d'un oesophagoscope rigide avec une fenêtre distale transparente à travers laquelle la muqueuse et une partie de la sous-muqueuse sont aspirées et ensuite réséquées avec une anse thermique. Les diverses fenêtres utilisées ont une taille comprise entre 2.2 et 4.4 cm. Le mouton a été choisi en raison de la ressemblance de son oesophage avec celui de l'humain en ce qui concerne l'épaisseur de son oesophage et sa structure histologique. Nous avons effectué 55 résections hémi-circonférentielles sur 21 animaux et 11 résections circonférentielles sur 11 autres. La Mitomycine-C, une substance qui inhibe la prolifération fibroblastique, a été utilisée dans 8 résections circonférentielles à différents intervalles de temps afin d'empêcher la survenue de sténoses oesophagiennes. Résultats : Toutes les résections hémi-circonférentielles ont permis d'obtenir des fragments compacts de tissu avec des bords nets, ce qui permet une excellente étude histologique. La surface du tissu prélevé était en corrélation avec la taille de la fenêtre du resectoscope. Nous avons ainsi pu obtenir des fragments avec des dimensions comprises entre 6 et 12 cm2. Pour les résections circonférentielles, les tissus étaient obtenus en 2 parties, en inversant de 180° la position de l'appareil. La profondeur de la résection a été optimale dans 58 cas sur 65 avec une découpe précise au niveau de la sous-muqueuse sans lésion de la couche musculaire sous- jacente. Il n'y a pas eu de complications après les résections hémi-circonférentielles. Les complications engendrées par les résections circonférentielles (sténose, perforation) n'ont plus été rencontrées après application locale de Mitomycine-C administrée à des intervalles de temps bien précis. Conclusion : Notre méthode de résection endoscopique de la muqueuse oesophagienne offre une nouvelle approche très prometteuse par rapport aux options déjà disponibles. Elle apparaît supérieure en ce qui concerne la taille de tissu prélevé, la précision et régularité de la profondeur de résection, ainsi que la facilité et sûreté du diagnostic histologique et des marges de sécurité. Les résections hémi-circonférentielles se sont révélées sûres chez le modèle animal. Cette nouvelle technique mérite de plus amples investigations pour les résections circonférentielles avant son utilisation chez l'humain. Abstract: Background and Study Aims: We undertook this retrospective study to evaluate the frequency and prognosis of endoscopic treatment of laterally spreading tumors (LSTs) in the rectum. The recurrence rate for lesions of the lower rectum was compared with that of the upper rectum. Patients and Methods: During the period from July 1989 to June 2002, a total of 1237 rectal tumors were detected. LSTs accounted for 6.9% (85/1237) of all rectal tumors. A total of 224 tumors of the lower rectum were detected among the 1237 rectal tumors. LSTs accounted for 16.1 % (36/224) of all the lower rectal tumors. From 85 LST lesions, 67 were evaluated for their prognosis after endoscopic mucosal resection (EMR). Patients whose LSTs had been resected were followed up by endoscopy at the following frequencies: once 15 (22.4%); twice (more than 1 year), 20 (29.9%); three times (more than 3 years), 21(31.3%); and four times or more (more than 5 years), 11 (16.4%). Results: A total of 67 patients with endoscopically treated LSTs were followed up by endoscopy. We observed recurrences in two lesions of the upper rectum (2/38, 5.3%) and five lesions of the lower rectum (5/29, 17.2%) (P = 0.2364); all seven lesions were resected piecemeal. LSTs whose horizontal margin reached the pectinate line frequently recurred in the lower rectum, at a rate of 80% (4/5). However, all patients were completely cured by additional endoscopic resections, the greatest number of treatments being four. Conclusion: For early detection of recurrence and successful endoscopic cure, further colonoscopic examination within a few months after the first treatment is necessary.

Ex vivo ultrasound control of resection margins during partial nephrectomy.

Purpose: Surgery remains the treatment of choice for localized renal neoplasms. While radical nephrectomy was long considered the gold standard, partial nephrectomy has equivalent oncological results for small tumors. The role of negative surgical margins continues to be debated. Intraoperative frozen section analysis is expensive and time-consuming. We assessed the feasibility of intraoperative ex vivo ultrasound of resection margins in patients undergoing partial nephrectomy and its correlation with margin status on definitive pathological evaluation.Materials and Methods: A study was done at 2 institutions from February 2008 to March 2011. Patients undergoing partial nephrectomy for T1-T2 renal tumors were included in analysis. Partial nephrectomy was done by a standardized minimal healthy tissue margin technique. After resection the specimen was kept in saline and tumor margin status was immediately determined by ex vivo ultrasound. Sequential images were obtained to evaluate the whole tumor pseudocapsule. Results were compared with margin status on definitive pathological evaluation.Results: A total of 19 men and 14 women with a mean +/- SD age of 62 +/- 11 years were included in analysis. Intraoperative ex vivo ultrasound revealed negative surgical margins in 30 cases and positive margins in 2 while it could not be done in 1. Final pathological results revealed negative margins in all except 1 case. Ultrasound sensitivity and specificity were 100% and 97%, respectively. Median ultrasound duration was 1 minute. Mean tumor and margin size was 3.6 +/- 2.2 cm and 1.5 +/- 0.7 mm, respectively.Conclusions: Intraoperative ex vivo ultrasound of resection margins in patients undergoing partial nephrectomy is feasible and efficient. Large sample studies are needed to confirm its promising accuracy to determine margin status.