[Our metabolic surgical activity, 2010-2016]. / Metabolikus sebészeti tevékenységünk, 2010­2016.

INTRODUCTION: The prevalence of morbid obesity and its co-morbidities - first of all diabetes type 2 - increased dramatically in the last decades. As the conservative ways of treatment (diet, training, etc.) in most cases does not lead to effective and long term weight loss, there is an increasing need for the metabolic surgical interventions. METHOD: During the last 6 and half years 514 laparoscopic RouxY gastric bypass (LRYGB) and 54 laparoscopic gastric sleeve resection (LGSR) were performed in our department. The data of random selected 40 patients after primary LRYGB and 15 patients after sleeve resection were collected. The applied criteria of the indication for surgery, the routine examinations and treatments before and after the intervention, the results and the type and the rate of the complications will be presented. RESULTS: According to our experience both procedures are long term effective for weight loss and for the resolution of co-morbidities, and can be performed with low risk of complications. After LRYGB more effective weight loss (extra weight loss 88% vs. 68%) and higher rate of resolution of diabetes type 2, hypertension and gastro-esophageal reflux were found compared to sleeve resection. CONCLUSION: Based on our results we prefer LRYGB. Gastric sleeve resection is indicated by us, when there is no way - or only with high risk - to perform gastric bypass, taking into consideration of course the individual requirements of the patients.

Decrease of morbidity in road traffic accidents in a high income country - an analysis of 24,405 accidents in a 21 year period.

BACKGROUND: The WHO initiated the "Decade of Action for Road Safety" because the fatality on road traffic accidents could become the fifth leading cause of death in 2030. On the contrary, fatalities continue to decrease in high income countries. The aim of the study was to find evidence for changes in injury severity of passenger car occupants after road traffic accidents in Germany over time, and to find contributing factors. METHODS: Data from the German In Depth Accident Study (GIDAS), representative for Germany, was used. A total of 24.405 accidents, reported from 1991 until 2011. 44.503 adult passenger car occupants were examined. A multivariable logistic regression model was developed to find reasons for observed trends over time. RESULTS: The relative decrease in mortality was 68.8% from 1991 until 2011. Between 2006 and 2011, the percentage of severely injured traffic victims was less than half, both in terms of the whole body and individual body regions. For injuries with an Abbreviated Injury Scale (AIS) ≥ 2, the percentage of persons with lower leg injuries declined by 72.5%, followed by the percentage of persons with pelvic injuries (61.5%), upper extremity injuries (57.7%), head injuries (54.3%), thorax injuries (50.0%), and abdomen injuries (40.0%). The multivariable regression model found 13 independent variables associated with injury prevention (e.g. seat belt use: OR 0.41, CI 95% 0.32-0.49; airbag: OR 0.86, CI 95% 0.75-0.99). The implementation of protective factors increased over time while accident constellations with a high probability for severe injury decreased over time. CONCLUSION: The decrease of severe injuries after road traffic accidents can be only attributed to a comprehensive approach including the enforcement of road safety policies and innovations in car engineering and emergency medicine. Traffic related measures and alcohol level control, and seat belt usage enforcement next to other technical advances are considered especially important.

Protein-based ultrafast photonic switching.

Several inorganic and organic materials have been suggested for utilization as nonlinear optical material performing light-controlled active functions in integrated optical circuits, however, none of them is considered to be the optimal solution. Here we present the first demonstration of a subpicosecond photonic switch by an alternative approach, where the active role is performed by a material of biological origin: the chromoprotein bacteriorhodopsin, via its ultrafast BR->K and BR->I transitions. The results may serve as a basis for the future realization of protein-based integrated optical devices that can eventually lead to a conceptual revolution in the development of telecommunications technologies.

Exvivo ultrasound attenuation coefficient for human cervical and uterine tissue from 5 to 10 MHz.

Attenuation estimation and imaging in the cervix has been utilized to evaluate the onset of cervical ripening during pregnancy. This feature has also been utilized for the acoustic characterization of leiomyomas and myometrial tissue. In this paper, we present direct narrowband substitution measurement values of the variation in the ultrasonic attenuation coefficient in ex vivo human uterine and cervical tissue, in the 5-10 MHz frequency range. At 5 MHz, the attenuation coefficient values are similar for the different orientations of uterine tissue with values of 4.1-4.2 dB/cm, 5.1 dB/cm for the leiomyoma, and 6.3 dB/cm for the cervix. As the frequency increases, the attenuation coefficient values increase and are also spread out, with a value of approximately 12.6 dB/cm for the uterus (both parallel and perpendicular), 16.0 for the leiomyoma, and 26.8 dB/cm for the cervix at 10 MHz. The attenuation coefficient measured increases monotonically over the frequency range measured following a power law.

Investigation of temperature-dependent viscoelastic properties of thermal lesions in ex vivo animal liver tissue.

The viscoelastic characteristics of thermal lesions in ex vivo animal liver are investigated in this paper. Characterization of the moduli of thermal lesions prepared at several temperatures will provide additional information for the elastographic monitoring of radio frequency ablation of hepatic tumors. In this study, the frequency-dependent complex modulus of thermal lesions prepared at temperatures ranging from 60 to 90 degrees C over a frequency range from 0.1 to 50Hz are presented. Lesions were prepared using either radio frequency ablation or double immersion boiling. It was found that both the magnitude and phase of the modulus increase with frequency, a behavior that has been noted in the literature. A new result reported shows that the modulus dependence on temperature reveals a local maximum around 70-75 degrees C corresponding to the temperature at which tissue has released most of its water content. The modulus values at temperatures higher than 70 degrees C continued to increase, but the extent of increase depend on animal species and other factors.

Auditory language comprehension of temporally reversed speech signals in native and non-native speakers.

Neuropsychological studies in brain-injured patients with aphasia and children with specific language-learning deficits have shown the dependence of language comprehension on auditory processing abilities, i.e. the detection of temporal order. An impairment of temporal-order perception can be simulated by time reversing segments of the speech signal. In our study, we investigated how different lengths of time-reversed segments in speech influenced comprehension in ten native German speakers and ten participants who had acquired German as a second language. Results show that native speakers were still able to understand the distorted speech at segment lengths of 50 ms, whereas non-native speakers only could identify sentences with reversed intervals of 32 ms duration. These differences in performance can be interpreted by different levels of semantic and lexical proficiency. Our method of temporally-distorted speech offers a new approach to assess language skills that indirectly taps into lexical and semantic competence of non-native speakers.

In vitro uterine strain imaging: preliminary results.

OBJECTIVE: Uterine abnormalities, such as leiomyomas, endometrial polyps, and adenomyosis, are often clinically associated with irregular uterine bleeding. These abnormalities can have similar B-mode characteristics but require different treatment. The objective of this study was to develop diagnostic techniques based on ultrasound strain imaging that would allow in vivo visualization and characterization of endometrial and myometrial uterine abnormalities, enabling physicians to improve diagnosis and treatment. METHODS: Ultrasound strain imaging was performed on 29 uteri removed via elective hysterectomy. An ultrasound system with a linear array transducer was used to obtain radio frequency echo data during manual freehand compressions of the tissue. Radio frequency data were post-processed with a 2-dimensional block-matching algorithm to generate strain images. RESULTS: In the uteri involved in this study, there were 19 leiomyomas, 1 case of adenomyosis, and 3 endometrial polyps observed on strain imaging. Leiomyomas appeared stiffer than the surrounding normal myometrium in strain images and were characterized by a slipping artifact at their boundary. Endometrial polyps appeared softer than the normal surrounding myometrium. The average strain contrast in small leiomyomas (<1.5 cm) compared to the myometrium was 1.75 +/- 1.14; the strain contrast was 2.50 +/- 1.15 in large leiomyomas and 0.40 +/- 0.05 in endometrial polyps. Leiomyoma strain contrast results were consistent with modulus contrast values from mechanical testing results. CONCLUSIONS: Ultrasound strain imaging can differentiate between endometrial polyps and leiomyomas. More data are necessary to validate these results and to ascertain whether other uterine abnormalities can also be differentiated.

Frequency-dependent complex modulus of the uterus: preliminary results.

The frequency-dependent complex moduli of human uterine tissue have been characterized. Quantification of the modulus is required for developing uterine ultrasound elastography as a viable imaging modality for diagnosing and monitoring causes for abnormal uterine bleeding and enlargement, as well assessing the integrity of uterine and cervical tissue. The complex modulus was measured in samples from hysterectomies of 24 patients ranging in age from 31 to 79 years. Measurements were done under small compressions of either 1 or 2%, at low pre-compression values (either 1 or 2%), and over a frequency range of 0.1-100 Hz. Modulus values of cervical tissue monotonically increased from approximately 30-90 kPa over the frequency range. Normal uterine tissue possessed modulus values over the same range, while leiomyomas, or uterine fibroids, exhibited values ranging from approximately 60-220 kPa.

Effects of display position of a visual in-vehicle task on simulated driving.

To determine the relative safety of onboard display positions while driving, participants performed a lane-keeping task in a driving simulator. Concurrently, they reacted to a light by pushing the brake pedal. A secondary task was projected onto a display at one of the seven different locations in the cockpit. Behavioral data, eye movements, and subjective rating scales showed that the manipulation of display information during driving disturbed drivers' performance exponentially as a function of distance between the line of sight to the outside primary task and the onboard display position. Vertical eccentricity had a greater detrimental effect than horizontal distance. Under a certain condition with a high secondary task load, reaction time of pushing the brake to the outside stimulus nearly doubled with a diagonal eccentricity of 35 degrees as compared to lower eccentricities. Subjective workload measures complement the behavioral data of clear detrimental effects with eccentricities of at least 35 degrees .

Monitoring stiffness changes in lesions after radiofrequency ablation at different temperatures and durations of ablation.

The variations in the stiffness or stiffness contrast of lesions resulting from radiofrequency (RF) ablation of canine liver tissue at different temperatures and for different ablation durations at a specified temperature are analyzed. Tissue stiffness, in general, increases with temperature; however, an anomaly exists around 80 degrees C, where the stiffness of the lesion is lower than that of the lesion ablated at 70 degrees C. On the other hand, the stiffness increases monotonically with the duration of ablation. Plots illustrating the ratio of mean strains in normal canine liver tissue to mean strains in ablated thermal lesions demonstrate the variation in the stiffness contrast of the thermal lesions. The contrast-to-noise ratio (CNRe) of the lesions, which serves as an indicator of the detectability of the lesions under the different experimental imaging conditions described above, is also presented. The results presented in this paper show that the elastographic depiction of stiffer thermal lesions is better, in terms of the CNRe parameter. An important criterion in the elastographic depiction of RF-ablated regions of tissue is the trade-off between ablation temperature and duration of ablation. Tissue necrosis can occur either by ablating tissue to high temperatures for short durations or to lower temperatures for longer durations. In this paper, we attempt to characterize the elastographic depiction of thermal lesions under these different experimental conditions. This paper provides results that may be utilized by practitioners of RF ablation to decide the ablation temperature and duration, on the basis of the strain images of normal liver tissue and ablated thermal lesions discussed in this paper.

Viscoelastic characterization of in vitro canine tissue.

Mechanical properties of biological tissues are of interest for assessing the performance of elastographic methods that evaluate the stiffness characteristics of tissue. The mechanical properties of interest include the frequency-dependent complex moduli, storage and loss moduli of tissues. Determination of the mechanical properties of biological tissues is often limited by proper geometry of the sample, as well as homogeneity of the stress-strain relationship. Measurements were performed on in vitro canine liver tissue specimens, over a frequency range from 0.1 to 400 Hz. Tests were conducted using an EnduraTEC ELF 3200, a dynamic testing system for determining the mechanical properties of materials. Both normal tissues and thermal lesions prepared by radio frequency ablation were tested. Experiments were conducted by uniaxially compressing tissue samples using Plexiglas platens larger than the specimens and measuring the load response. The resulting moduli spectra were then fit to a modified Kelvin-Voigt model, called the Kelvin-Voigt fractional derivative model. The data agree well with the model and in comparing the results from the normal tissue with that of the thermal lesions, the concept of a complex modulus contrast is introduced and its applications to elastography are discussed.

Improved image contrast of calcifications in breast tissue specimens using diffraction enhanced imaging.

The contrast of calcifications in images of breast tissue specimens using a synchrotron-based diffraction enhanced imaging (DEI) apparatus has been measured and is compared to the contrast in images acquired using a conventional synchrotron-based radiographic imaging modality. DEI is an imaging modality which derives image contrast from x-ray absorption, refraction and small-angle scatter-rejection (extinction), unlike conventional radiographic techniques, which can only derive contrast from absorption. DEI is accomplished by inserting an analyser crystal in the beam path between the sample and the detector. Two of the three breast tissue specimens contained calcifications associated with cancer, while a third contained benign calcifications. Results of the image analysis indicate that the DEI contrast of images taken with the analyser crystal tuned to the peak of its rocking curve, was as much as 19 times that of the conventional radiograph, with an average of 5.5 for all calcifications. This improved image contrast for even near-pixel-size calcifications suggests potential utility for DEI in breast imaging.

Measurement of image contrast using diffraction enhanced imaging.

Refraction contrast of simple objects obtained using diffraction enhanced imaging (DEI) was studied and compared to conventional radiographic contrast. Lucite cylinders and nylon wires were imaged using monochromatic synchrotron radiation at the National Synchrotron Light Source (http://nslsweb. nsls.bnl.gov/nsls/Default.htm) at the Brookhaven National Laboratory. The DEI images were obtained by placing a silicon analyser crystal tuned to the [333] diffraction plane in the beam path between the sample and the detector. To compare the DEI images with conventional radiographic images requires a consistent definition of refraction and absorption contrast. Conventional definitions of contrast favour conventional radiography and DEI contrast is defined to emphasize the specific characteristics of DEI. The proposed definitions were then used to find the DEI gain (the ratio of the DEI contrast with respect to the conventional image contrast). The results presented here show that the DEI gain is consistently greater than 1, indicating that DEI provides more contrast information than conventional radiography.