Understanding flow patterns from the field - Controlled laboratory experiments on the transport behavior of veterinary antibiotics in the presence of liquid manure

The main entry path of veterinary antibiotics to the environment is the application of liquid manure on agricultural land. Along with the manure, they can infiltrate into soils and leach into groundwater. As the environmental behavior of veterinary antibiotics is strongly affected by the process of sorption, the comprehensive knowledge regarding their sorption behavior is key to a reliable risk assessment. However, the flow patterns in field experiments are influenced by several factors that can hardly be distinguished, while most of the sorption studies on veterinary antibiotics were designed without manure or as batch experiments, which means that the effects of manure on the transport behavior of the antibiotic substances remained unaccounted for. In order to understand the results from a previous field experiment and concurrently fill the identified knowledge gap, a column experiment was performed to investigate the effects of manure on the transport of sulfamethazine, sulfadiazine, tetracycline, and lincomycin in soil. Results show that sulfamethazine and sulfadiazine were highly mobile in both the presence and absence of manure, while tetracycline did not appear at the outlet of any column. Despite their high mobility, in the presence of manure the sulfonamides were slightly delayed compared to the conservative tracer as was also seen during the previous field experiment. Lincomycin transport was already delayed in the absence of manure. Furthermore, in the presence of manure, lincomycin was delayed by 4.5 times relative to the tracer, which clearly underlined the influence of manure on the transport of lincomycin and offers an explanation why lincomycin has barely been detected in the long-term field experiment. However, in contrast to the results obtained in the field experiment, the recovery rates were the same in presence and absence of manure for both sulfonamides and lincomycin, probably due to reduced degradation at the applied concentration level.

Light-emitting diode based on mask- and catalyst-free grown N-polar GaN nanorods

We report on the fabrication of a light-emitting diode based on GaN nanorods containing InGaN quantum wells. The unique system consists of tilted N-polar nanorods of high crystalline quality. Photoluminescence, electroluminescence, and spatially resolved cathodoluminescence investigations consistently show quantum well emission around 2.6 eV. Scanning transmission electron microscopy and energy-dispersive x-ray spectroscopy measurements reveal a truncated shape of the quantum wells with In contents of (15 ± 5)%.

[Radial MRI of the hip joint for evaluation of degenerative changes in the young adult: a comparison of different sequences]

AIM

Femoroacetabular impingement has been shown to be an important cause for the development of osteoarthritis of the hip joint. Radial MRI of the hip has proven to be the diagnostic procedure of choice to differentiate which patient to operate. While examinations after instillation of contrast agents have been described, new papers have shown high accuracy without contrast medium. Since instillation of contrast medium is considered painful and poses the risk of infection, it is not performed for MRI evaluation of the hip at our institution. However, the question as to which sequence to use has not been settled yet. Therefore, four frequently used sequences using the same resolution were compared.

MATERIALS AND METHODS

A retrospective analysis of T (1)-weighted (T (1)), T (2)-weighted (T (2)) and proton density sequences (the latter with and without fat saturation [PDfs and PD]) of 50 hips in 48 patients with femoro-acetabular impingement and developmental dysplasia of the hip was performed by two raters blinded to the clinical information. The different sequences were rated separately. Evaluated criteria were subjective imaging quality, power to differentiate acetabular from femoral cartilage as well as the labrum from the joint capsule, and localisation and characterisation of pathological changes in joint cartilage, the labrum and at the femoral head-neck junction.

RESULTS

Subjective imaging quality was assessed to be similar for T (1), PDfs and PD, whereas it was significantly worse for T (2). In discriminating specific intraarticular structures, however, only PDfs and PD were superior. The differentiation of acetabular from femoral cartilage was possible in only 44% and 40% of T (1) and T (2) images, but in 79% and 76% of PDfs and PD images. Similar results were found for the differentiation of the acetabular labrum from its vicinity, especially the joint capsule (36%, 35%, 77% and 74%, respectively). Intralabral pathology was seen in a comparable extent in all sequences. An intramedullary oedema at the head-neck junction, however, was significantly more frequent in PDfs only (67% vs. 0%, 17% and 10% for PDfs vs. T (1), T (2) and PD).

CONCLUSION

Despite their good subjective quality, T (1)- and T (2-)weighted sequences could not depict the acetabular labrum as efficiently as PD-weighted sequences. Concluding from our data, a PDfs sequence (possibly combined with a conventional PD sequence) is advantageous over T (1) and T (2) sequences. Intraarticular administration of contrast medium seems to be superfluous.

Perception and suppression of thermally induced pain: a fMRI study

Two neuroimaging studies using functional magnetic resonance imaging (fMRI) and thermally induced pain are presented. Fifteen healthy right-handed subjects were imaged while they had to discern different levels of thermal stimuli in the first study and while they disengaged from the feeling of pain during constant stimulation in the second study. In the first experiment, during painful phasic stimuli, right-sided anterior insular activation as well as bilateral posterior insular activation could be shown regardless of stimulation side, as well as right-sided activation of sensory association areas in the superior parietal lobule. Also, activation of the ipsilateral sensorimotor cortex could be shown. In the second experiment, all subjects succeeded in suppressing the feeling of pain during previously painful levels of stimulation. During the early part of the tonic painful stimulation, bilateral activation of caudate head and dorsolateral prefrontal cortex (DLPFC) as well as insular cortex and dorsal anterior cingulated cortex (dACC) was observed. During the late part of the tonic painful stimulation, anterior insular activation as well as dACC and bilateral prefrontal cortical activation could be shown. Taken together, the activation of PFC and caudate nucleus hints at an important role in the initiation (caudate) and maintenance (PFC) of suppression of the feeling of pain. No ipsilateral sensorimotor activation could be shown in the second experiment. The possible import of unwanted sensorimotor activation due to the simultaneous rating process in the first experiment is discussed.

Acute gastrointestinal bleeding: value of MDCT

Contrast-enhanced multidetector row helical computed tomography (MDCT) scanning is establishing itself as a rapid, noninvasive, and accurate diagnostic method in suspected acute gastrointestinal bleeding. Active bleeding can be depicted as an area of focal high attenuation within the bowel lumen on arterial phase MDCT images. New MDCT technologies facilitate three-dimensional image reconstruction, and higher temporal resolution is available with new MDCT scanner generations. This allows for the acquisition of arterial- and portal-venous phase images of the whole abdomen, revealing potential bleeding sources and simultaneously depict morphological changes in the abdomen, such as intestinal tumors. This article gives an overview of available diagnostic modalities in assessing gastrointestinal (GI) tract hemorrhage, with a special emphasis on new MDCT technology.

Transient Global Amnesia – Full Recovery without Persistent Cognitive Impairment

Transient global amnesia (TGA) is a clinical syndrome of unknown etiology characterized by sudden onset anterograde amnesia, which was thought to resolve completely. However, some authors have also suggested permanent memory impairment. It is unclear whether these results reflect a true persistent damage or a simply too short assessment interval in the context of a prolonged recovery phase after TGA. To evaluate the cognitive long-term outcome, 16 patients who had suffered from TGA at a mean of 3 years before and 15 healthy controls underwent a comprehensive neuropsychological test battery. No significant differences between patients' and controls' cognitive performance were found, irrespectively of the analyzed neuropsychological domain. Therefore we hypothesize that TGA usually does not cause persistent cognitive deficits due to a generally transient and prognostic benign character.

Beschwerden im Verlauf nach konservativ behandelten distalen Radiusfrakturen - Prädiktoren aus der initialen Röntgenaufnahme

PURPOSE

Radius fractures are frequent in adults, and the long-term results of conservative treatment remain disappointing. This study examines predictors for the clinical outcome in the initial radiograph. This will help to identify patients who will benefit from surgical treatment.

MATERIALS AND METHODS

A cohort study including a standardized telephone interview (Cooney score) was used to identify all conservatively treated patients with a distal radius fracture over a five-year period. The additional selection criteria were: over 15 years old, initial X-ray available, patient reachable by phone for the follow-up interview. The following measurements were taken from the initial radiograph: radius-base angle, radial shortening, radiopalmar angle and intraarticular displacement. Correlations and a simple test to predict negative outcome were computed.

RESULTS

Of the initially identified 2211 patients with distal radius fracture, 179 also fulfilled the other criteria. The patients were 56.2 years old on average (standard deviation SD = +/- 22.45 years) and 72 % were female. 60 % of the fractures were on the right side. The average follow-up was 4.3 years (SD +/- 1.66). The Cooney score results averaged 85 points (with 100 being the optimal and maximum score), indicating good or very good functional results in the long term follow-up for 61 % of patients. However, 31 % received a rating of fair or poor and therefore had an unfavorable outcome. With respect to the correlations, age and shortening of the radius (but not gender) had a significant influence on the functional result. Using an age of 75 years or above and a radial shortening of at least 4 mm to predict an unfavorable outcome, the sensitivity is only 16 %, but the positive predictive value is 73 % and the specificity is 96 %.

CONCLUSION

In the analysis of the initial radiographs after distal radius fracture, age and radial shortening primarily correlate with functional results after four years after conservative treatment. Using the values age > or = 75 and radial shortening > or = 4 mm, it is possible to predict an unfavorable functional outcome with a positive predictive value of 73 %. This could aid in the indication of operative treatment.

Laterale Ischiadikusblockaden

In the present study we examined 41 volunteers using magnetic resonance imaging to obtain biometric data of the thigh used for a planned blockade of the sciatic nerve via the lateral approach. At a needle entry point 12 cm proximal to the gap of the knee joint at the posterior border of the M. vastus lateralis, the sciatic nerve lies on average at a depth of 5.2 cm (39% of the femoral diameter at this site) with an angle of 10.9 degrees to the horizontal in a dorsal direction. Here the popliteal artery lies on average at a depth of 6.4 cm (48% of the femoral diameter) with an angle of 4.7 degrees to the horizontal in a ventral direction. At the marked point in the middle between the gap of the knee joint and the trochanter major at the posterior border of the M. vastus lateralis, the sciatic nerve is at an average depth of 6.2 cm (40% of the femoral diameter at this site) with an angle of 8.2 degrees in a dorsal direction. At a marked point 5 cm distal of the trochanter major at the posterior border of the M. vastus lateralis, the sciatic nerve is at a depth of 9.1 cm at a dorsal angle of 15.5 degrees (49% of the femoral diameter). The lateral blockade of the sciatic nerve at different sites of the thigh is a technique which is easy to plan with the presented biometric data. The popliteal artery could be reached only at the distal puncture point using a deep puncture and an angle in the ventral direction.

Schedule- and dose-intensified paclitaxel as weekly 1-hour infusion in pretreated solid tumors: results of a phase I/II trial

Paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) has been studied primarily on a 3-week schedule as a 3-, 24-, or 96-hour infusion at doses ranging from 135 to 250 mg/m2. The observed toxicity profile seems to be both dose and schedule dependent. Dose densification of paclitaxel given weekly over 6 weeks on a split-dose schedule for an overall increase in dose intensity was thought to improve the therapeutic index of paclitaxel in a variety of advanced malignancies and to be suitable for outpatient administration. For this study, chemotherapy consisted of a weekly 1-hour infusion of paclitaxel at a starting dose of 40 mg/m2/wk for 6 weeks, followed by a 2- to 3-week interval. Paclitaxel dosage was escalated in 10 mg/m2/wk increments in subsequent patients, to a maximum dosage of 90 mg/m2/wk. Intravenous dexamethasone, cimetidine, clemastine, and ondansetron were administered immediately before the paclitaxel infusion. Fifty patients participated in the study. The male to female ratio was 21 to 29, the median age was 53.2 years (age range, 33 to 74), and the median performance status was 1. All patients were chemotherapeutically pretreated. Overall response included five complete responses (10%), 15 partial responses (30%), 19 no change (38%), and 11 disease progressions (22%). Median dose intensity was 410 mg/m2/6 wk (range, 200 to 540 mg/m2/6 wk). Hematologic toxicity was mild, with no grade 3 or 4 toxicity up to 90 mg/m2/wk. No hypersensitivity reactions or neurologic or cardiac toxicities were documented. Dose-densified, weekly paclitaxel is concluded to be active in a variety of pretreated tumor entities. The overall low hematologic and peripheral toxicity profile suggests that further dose intensification of weekly paclitaxel and/or combination with other cytotoxic agents (eg, cisplatin/carboplatin, ifosfamide, etoposide) may be warranted. Paclitaxel can be given safely in the outpatient setting. Paclitaxel 90 mg/m2/wk is recommended for single-agent treatment. Dose-densified paclitaxel may be considered a valuable and promising alternative to standard 3-week treatment, with further options possible in combination chemotherapy.