Comparison of Data-Dependent Acquisition, Data-Independent Acquisition, and Parallel Reaction Monitoring in Trapped Ion Mobility Spectrometry-Time-of-Flight Tandem Mass Spectrometry-Based Lipidomics.

The parallel accumulation-serial fragmentation (PASEF) approach based on trapped ion mobility spectrometry (TIMS) enables mobility-resolved fragmentation and a higher number of fragments in the same time period compared to conventional MS/MS experiments. Furthermore, the ion mobility dimension offers novel approaches for fragmentation. Using parallel reaction monitoring (prm), the ion mobility dimension allows a more accurate selection of precursor windows, while using data-independent aquisition (dia) spectral quality is improved through ion-mobility filtering. Owing to favorable implementation in proteomics, the transferability of these PASEF modes to lipidomics is of great interest, especially as a result of the high complexity of analytes with similar fragments. However, these novel PASEF modes have not yet been thoroughly evaluated for lipidomics applications. Therefore, data-dependent acquisition (dda)-, dia-, and prm-PASEF were compared using hydrophilic interaction liquid chromatography (HILIC) for phospholipid class separation in human plasma samples. Results show that all three PASEF modes are generally suitable for usage in lipidomics. Although dia-PASEF achieves a high sensitivity in generating MS/MS spectra, the fragment-to-precursor assignment for lipids with both, similar retention time as well as ion mobility, was difficult in HILIC-MS/MS. Therefore, dda-PASEF is the method of choice to investigate unknown samples. However, the best data quality was achieved by prm-PASEF, owing to the focus on fragmentation of specified targets. The high selectivity and sensitivity in generating MS/MS spectra of prm-PASEF could be a potential alternative for targeted lipidomics, e.g., in clinical applications.

Gait pattern of heifers before and after claw trimming: a high-speed cinematographic study on a treadmill.

The manner in which the claws contacted the ground at the walk was evaluated in 18 healthy heifers. The animals were filmed before and after claw trimming while walking on a treadmill using high-speed cinematography (500 frames/s). For each limb, 4 consecutive steps were recorded from a side and a frontal plane. The objectives of the study were to evaluate 1) the order of claw contact with the treadmill surface, 2) the initial claw contact area, and 3) the effect of trimming on claw contact patterns. The heifers placed their front feet on the ground in a plane sagittal to the shoulders, whereas the hind feet were advanced more toward the median plane. Before trimming, the lateral claws contacted the ground before the medial in 83% of front and 100% of hind limbs. Trimming changed the percentage to 92% in the front and to 97% in the hind limbs. The percentage with which the heel of the lateral claws became the region of initial contact with the ground increased from 47 to 64% in the front feet and from 50 to 78% in the hind feet. In the medial claws of the forelimbs, claw trimming shifted the region of initial contact from the toe to the abaxial wall and heel. In the hind limbs, the main region of initial contact of the medial claws became the abaxial wall. Weight bearing by the medial claw became visibly apparent only during the midstance, propulsion, and push-off phases. "Heel first" contact of the lateral claws in the front and hind limbs may be the normal gait pattern in cattle. On hard surfaces, this pattern may lead to overload and predispose to disease, especially in the hind limbs.

[Surgical treatment of coxofemoral luxation in two cattle]. / Operative Behandlung einer Luxatio ossis femoris bei zwei Rindern.

A three-week-old Holstein Friesian calf and a 20-month-old Jersey heifer were referred to the Department of Farm Animals, University of Zurich, because of coxofemoral luxation. Both animals were moderately lame on the affected hind limb, which was swollen in the hip region and appeared to be adducted and shorter than the contralateral normal hind limb. Radiographs of the affected hips confirmed craniodorsal displacement of the femur. In both animals, traction and open reduction was carried out under general anaesthesia. The joint capsule, which was severely torn, was repaired using suture material or a non absorbable mesh. In the calf, two 4.5-mm screws and washers were placed in the dorsal rim of the acetabulum. Strong non-absorbable suture material of USP 6 in size was placed around each screw and through a pre-drilled hole in the femoral neck and back to the screw in a figure-8 pattern. The sutures were tied and the screws tightened. In the heifer, a non-absorbable mesh was attached to the dorsal acetabular rim using three 4.5-mm cortical screws. The mesh was sutured to the joint capsule at the femoral neck using strong non-absorbable suture material in a simple continuous pattern. Complications were not encountered during the postoperative period. Six months after discharge, both animals were in good general health, although the heifer had mild lameness and muscle atrophy in the operated limb.

Quantitative bone and 67Ga scintigraphy in the differentiation of necrotizing external otitis from severe external otitis.

Qualitative technetium Tc 99m bone scintigraphy using phosphate compounds and gallium 67 scintigraphy were described as a helpful means in diagnosing necrotizing external otitis (NEO). They were, however, claimed to be nonspecific. Quantitative Tc 99m methylene diphosphonate bone scintigraphy and gallium 67 scintigraphy were performed in eight patients with NEO and in 20 patients with severe external otitis, in order to prove usefulness of scintigraphy in the diagnosis of NEO. Ratios of lesion to nonlesion for bone scintigraphy were 1.67 +/- 0.16 in patients with NEO and 1.08 +/- 0.09 in patients with severe external otitis, and for gallium 67 scintigraphy they were 1.35 +/- 0.24 in NEO patients and 1.05 +/- 0.03 in patients with severe external otitis. There was no difference in uptake between diabetic patients with severe external otitis and nondiabetic patients. The scintigraphic studies were also evaluated using a qualitative scoring method (scores 0 to +4), according to the intensity of the radiopharmaceutical uptake. This method was found to be inferior in the diagnosis of NEO compared with the quantitative method. We conclude that lesion-to-nonlesion ratios greater than 1.5 and 1.3 on bone and gallium 67 scintigraphy, respectively, are indicative of NEO. Quantitative bone scintigraphy, which is quicker to perform, may be used as a single imaging modality for the diagnosis of NEO.

An evaluation of the toxicity of carbon fiber composites for lung cells in vitro and in vivo.

Carbon fiber composite materials are used in a variety of applications in industries, and machining processes often generate aerosols of these materials in the workplace. Because the potential health effects of these particles are uncertain, we evaluated the toxicity of a series of carbon fiber composites in vitro using rabbit alveolar macrophages and in vivo using direct intratracheal injection into rat lungs. For comparison, we studied two reference materials, Al2O3 and alpha-quartz, which are inert and toxic, respectively. We measured cytotoxicity in vitro for rabbit alveolar macrophages by trypan blue exclusion and by the release of 51Cr from prelabeled macrophages. We also injected the samples intratracheally into specific pathogen-free rats and 1 month later lavaged the lungs to recover airway cells and fluid. In each of the assays, the quartz was the most toxic substance tested, causing marked cytotoxicity for alveolar macrophages and large increases in airway cells and neutrophils in the rat lungs, whereas the Al2O3 was consistently the least toxic. Three of the composite samples consistently showed little toxicity, whereas two were consistently toxic for alveolar macrophages and caused significant accumulations of airway cells and neutrophils in the rat lungs. The results of the in vitro and in vivo studies produced a similar ranking of toxicity for all of the samples. These studies show that in vitro and in vivo testing is a useful approach to the evaluation of the potential biologic effects of new materials in the lungs. Although these carbon fiber composites appear to be much less toxic than quartz, the data suggest that two of the composites are not inert. Exposure limits more strict than those for nuisance dusts should be used in the workplace for these two composites. Longer term inhalation exposure studies using these two composites are warranted in order to better define their effects in the lungs.

Skull molding caps: an adjunct to craniosynostosis surgery.

External cranial vault molding using dynamic splinting is an adjunct to surgery in the treatment of craniosynostosis skull deformities. The skull molding cap not only maintains desired skull form, but also provides further active molding to normalize skull shape. Dynamic skull remodeling from these devices occurs primarily by translational movements of bone. Traction and compression result in bony repositioning which allows further reshaping as the osteoblasts and osteoclasts respond to these stresses. Three basic designs have been described. In practice, each one must be modified to meet individual needs, and adaptations are made according to established principles of dynamic splinting.