Sorption of Selected Aromatic Substances��Application of Kinetic Concepts and Quantum Mechanical Modeling

Prediction of the sorption behavior of environmental pollutants is of utmost importance within the framework of risk assessments. In this work two approaches are presented with the aim to describe sorption of aromatic substances to geosorbents. First, analytical solutions of kinetic models were fitted to experimental data of batch sorption experiments with aniline and 1-naphthylamine onto animal manure-treated soil and the soil mineral montmorillonite. The models, accounting for equilibrium and nonequilibrium sorption coupled to transformation and/or irreversible sorption processes, could well reproduce the concentration course of the sorbates. Results suggest that the amounts transformed/degraded and irreversibly bound were higher for the soil than for the clay mineral. In the second part, quantum chemical calculations were performed on aniline and 1-naphthylamine interacting with acetic acid, acetamide, imidazole, and phenol as models of functional groups present in humic substances. Molecular modeling showed that formation of hydrogen bonds is the dominating binding mechanism in all modeled complexes, which are energetically very similar between aniline and 1-naphthylamine.     

Intermittent positive pressure ventilation with constant positive end-expiratory pressure and alveolar recruitment manoeuvre during inhalation anaesthesia in horses undergoing surgery for colic, and its influence on the early recovery period

Objective To compare, ventilation using intermittent positive pressure ventilation (IPPV) with constant positive end‐expiratory pressure (PEEP) and alveolar recruitment manoeuvres (RM) to classical IPPV without PEEP on gas exchange during anaesthesia and early recovery. Study design Prospective randomized study. Animals Twenty‐four warm‐blood horses, weight mean 548 ± SD 49 kg undergoing surgery for colic. Methods Premedication, induction and maintenance (isoflurane in oxygen) were identical in all horses. Group C (n = 12) was ventilated using conventional IPPV, inspiratory pressure (PIP) 35–45 cmH₂O; group RM (n = 12) using similar IPPV with constant PEEP (10 cmH₂O) and intermittent RMs (three consecutive breaths PIP 60, 80 then 60 cmH₂O, held for 10–12 seconds). RMs were applied as required to maintain arterial oxygen tension (PaO₂) at >400 mmHg (53.3 kPa). Physiological parameters were recorded intraoperatively. Arterial blood gases were measured intra‐ and postoperatively. Recovery times and quality of recovery were measured or scored. Results Statistically significant findings were that horses in group RM had an overall higher PaO₂ (432 ± 101 mmHg) than those in group C (187 ± 112 mmHg) at all time points including during the early recovery period. Recovery time to standing position was significantly shorter in group RM (49.6 ± 20.7 minutes) than group C (70.7 ± 24.9). Other measured parameters did not differ significantly. The median (range) of number of RMs required to maintain PaO₂ above 400 mmHg per anaesthetic was 3 (1–8). Conclusion Ventilation using IPPV with constant PEEP and RM improved arterial oxygenation lasting into the early recovery period in conjunction with faster recovery of similar quality. However this ventilation mode was not able to open up the lung completely and to keep it open without repeated recruitment. Clinical relevance This mode of ventilation may provide a clinically practicable method of improving oxygenation in anaesthetized horses.     

Plasma and urine concentrations of marbofloxacin following single subcutaneous administration to cats

The pharmacokinetic properties of marbofoxacin, a third generation fluoroquinolone, were investigated in 12 healthy adult cats after single subcutaneous (SC) administration of 2 mg/kg BW (Part I, n=8 cats) and 4 mg/kg BW (Part II, n=4 cats). In each part of the study blood and urine samples were collected before treatment and thereafter for 5 days. The plasma and urine concentrations of marbofloxacin were determined by HPLC with UV detection. Pharmacokinetic calculations were performed for each treated animal using an open one-compartment-model with first-order elimination after SC dosing. Marbofloxacin in plasma (means): Maximum concentrations (Cmax) of about 1.2 and 3.0 microg/ml were measured 2.3 and 4 hours (tmax) after dosing of 2 and 4 mg/kg BW, respectively. Elimination from the body was low with a total clearance (Cl/F) of approximately 0.1 l/h/kg for both dosages. The half-life (t 1/2) for this process was calculated with 8-10 hours. AUC increased almost proportional when doubling the dose, i.e., 19.77 +/- 6.25 microg * h/ml (2 mg/kg BW) and 51.26 +/- 11.83 microg * h/ml (4 mg/kg BW). Plasma kinetics measured were in accordance with data from literature. Marbofloxacin in urine (means): Maximum drug concentrations were detected 4 and 8 hours after dosing with 70 microg/ml (2 mg/kg BW) and 160 microg/ml (4 mg/kg BW), respectively. Inhibitory effects of the urinary matrix on the antimicrobial activity of the drug were taken into account when performing PK/PD calculations. However, a concentration-dependent bactericidal activity (Cmax/MIC > 8-10) which is claimed for fluoroquinolones was sufficiently met with focus on Escherichia (E.) coli (MIC90 0.5 microg/ml). In the same matrix a threshold value of 1.0 microg/ml was undercut 82 and 116 hours after SC dosing, respectively. Hence, a time-dependent bacteria killing kinetic (T > MIC) which may be of relevance for some Gram-positive germs like Staphylococcus spp. (MIC90 1.0 microg/ml) should be covered, too.     

The sylvatic Trichinella cycle and its implications for Trichinella control in Germany

Trichinellosis is a food-borne, zoonotic disease caused by a parasitic organism. Pork containing muscle larvae represents the most important source of human trichinellosis. In Germany, each slaughtered domestic swine is systematically sampled and examined for Trichinella spp. European Union legislation (EC (No.) 2075/2005) condones the approach of a risk-oriented meat inspection for Trichinella in pigs which is accompanied by monitoring programmes for pig holdings and reservoir animals. Here we discuss the current epidemiological situation of Trichinella in the sylvatic cycle in Germany and the implications for the implementation of risk-based sampling.     

Viability assessment of spermatozoa in large falcons (Falco spp.) using various staining protocols

Viability assessment is an important part of semen analysis, and various live/dead staining protocols have been used in semen of avian species. Results of live/dead count differed between dyes, staining protocols and bird species, impeding comparability between studies and requiring species-specific comparisons of viability stains. In raptor semen, similar comparisons are absent. Thus, the aim of the present study was to compare eight conventional viability stains. Eosin blue 2% [EB], eosin blue 2% with the addition of 3% sodium citrate [EB2], eosin blue–nigrosin 5% [EBN5], eosin yellow–nigrosin 5% [EYN5], eosin yellow–nigrosin 10% [EYN10], eosin blue–aniline blue [EBA], eosin yellow–aniline blue [EYA] and bromophenol blue–nigrosin [BBN] were evaluated in comparison with the fluorescence stain SYBR^® Green–propidium iodide [SYBR-PI] in spermatozoa of falcons. The comparison was performed using conventional light microscopy which is applicable in breeding centres, veterinary practices and field studies. Additionally, live/dead stains were correlated to motility values of the same samples to validate sperm viability. Light microscopy using EB and using SYBR-PI enabled an effective and clear differentiation between alive and dead spermatozoa of falcons. Motility values correlated significantly and strongly with EB only (r = .629; p < .001), but not with any other stain used in the study. Therefore, our results suggest EB as the most suitable stain for viability assessment in the semen of large falcons.     

THE CANINE TROCHANTERIC FOSSA: A RADIOGRAPHIC AND ANATOMIC STUDY

Radiographic features of the region of the trochanteric fossa were evaluated bilaterally on 175 ventrodorsal radiographs of canine hip joints and findings were compared to anatomic specimens. The fossa showed a variable radiographic appearance, which was affected by positioning and anatomic diversity. On a small number of radiographs (n = 12), the trochanteric fossa was clearly defined as a circular area of radiopacity surrounded by a radiolucent halo. This appearance was significantly influenced by medial rotation of the femur (P < 0.001). On some anatomic specimens an irregular protuberance representing the site of attachment of the gemelli, internal and external obturator muscles was seen within the fossa, surrounded by a variable number of small openings, which were thought to be nutrient foramina. Dissection identified a small number of minor branches of the medial circumflex femoral artery entering these.     

Effects of induced endometritis on uterine blood flow in cows as evaluated by transrectal Doppler sonography

This study was conducted to evaluate the effects of induced endometritis on uterine blood flow in cows. Transrectal Doppler sonography was performed on uterine arteries of six cyclic cows before and for 4 days after inducing acute endometritis by intrauterine infusion of 720 mg of policresulen, and for 4 days of the following estrous cycle. Time-averaged maximum velocity (TAMV) increased (p < 0.001) and pulsatility index (PI) decreased (p < 0.0001) within 1 h of policresulen administration, and did not change (p > 0.05) in the next 4 days of the same cycle. TAMV and PI values in the subsequent cycle did not differ (p > 0.05) from the values measured before infusion and showed no changes (p > 0.05) within the cycle. Blood flow parameters were not related (p > 0.05) to plasma concentrations of progesterone and estrogen. All cows showed an acute endometritis determined by histopathological findings of biopsy samples taken 1 day after infusion and fibrotic endometrial alterations detected in the subsequent cycle. No relationships were observed between fibrotic changes of the endometrium and uterine blood flow during either cycle. In conclusion, acute inflammation is accompanied by a rise in uterine blood flow, but fibrotic alterations do not seem to be related to Doppler sonographic findings.