Geometric modelling of error sources for tibial plateau levelling osteotomy in the dog.

Tibial plateau levelling osteotomy is widely performed for stabilization of cranial cruciate ligament deficient stifles in dogs. A wide range of postoperative tibial plateau angles around the target angle has been reported. The main aim of this study was to investigate if osteotomy placement could explain this range. Landmarks were derived from 50 tibial radiographs by five observers and used to define osteotomy placement and correction angles for simulation. Observer-specific osteotomy locations with mean landmark data were used to simulate planning errors, and simulated malpositioning of the osteotomy at 5 mm and 10 mm from the ideal location was used to simulate surgical errors. The tibial plateau midpoint was used as the ideal centre of the osteotomy in this model. Planning errors mostly arose from tibial plateau misidentification, with osteotomy centre locations dispersed up to 2.4% of tibial length from ideal. Malpositioning of the osteotomy resulted in variable changes in tibial plateau angle. Synthesis with historical data suggested such changes are likely limited in magnitude in tibiae with a mechanical axis length over 140 mm, but will be greater in smaller dogs and with steeper tibial plateaus. In medium to large breed dogs, our findings indicate osteotomy inaccuracy alone cannot explain the reported postoperative ranges in tibial plateau angles. Other error sources such as rotational inaccuracies or shifts during implant placement may be more significant. Surgeons should exercise additional caution when operating small and miniature breeds due to the much larger potential for clinically significant errors in these smaller dogs.

Geometric modelling of CORA-based levelling osteotomy in the dog.

Centre of rotation of angulation (CORA)-based levelling osteotomy (CBLO) is a recent addition to surgical procedures for stabilization of the cranial cruciate ligament-deficient canine stifle joint. Careful identification of the CORA location preoperatively and use of this location intraoperatively are required to ensure accurate correction of the tibial plateau angle. Limited data are available regarding the magnitude and source of potential errors during planning and execution of CBLO. A geometric model enabling isolation of various error sources is described. Landmarks were derived from tibial radiographs (n = 50) by 5 observers and used to define proximal and distal anatomical axes for simulation of CBLO. Observer-specific CORA locations with mean landmark data were used to assess planning errors, and simulated malpositioning of the CORA at 10 mm from the ideal location was used to assess surgical errors. Planning errors result mainly from tibial plateau misidentification, with CORA locations dispersed up to ±10 mm proximodistally from ideal (95% confidence). Malpositioning of the CORA during surgery causes equal and opposite changes in tibial plateau angle (TPA) and anatomical-mechanical axis angles, and varying degrees of translation and limb length changes. The magnitude of these changes is dependent on initial TPA and limb length, with smaller dogs and steeper tibial plateaus resulting in larger errors. Optimal planning and execution are required to achieve the planned outcome of CBLO. The main source of error in our simulation is identification of the tibial plateau. While both pre- and intraoperative errors influenced TPA, based on our geometric model the effect in larger dogs may not be clinically significant. If distalisation of the CORA is required during surgery, compensation of the CORA angle to maintain the target TPA is possible.

Reef-coral proteins as visual, non-destructive reporters for plant transformation.

Recently, five novel fluorescent proteins have been isolated from non-bioluminescent species of reef-coral organisms and have been made available through ClonTech. They are AmCyan, AsRed, DsRed, ZsGreen and ZsYellow. These proteins are valuable as reporters for transformation because they do not require a substrate or external co-factor to emit fluorescence and can be tested in vivo without destruction of the tissue under study. We have evaluated them in a large range of plants, both monocots and dicots, and our results indicate that they are valuable reporting tools for transformation in a wide variety of crops. We report here their successful expression in wheat, maize, barley, rice, banana, onion, soybean, cotton, tobacco, potato and tomato. Transient expression could be observed as early as 24 h after DNA delivery in some cases, allowing for very clear visualization of individually transformed cells. Stable transgenic events were generated, using mannose, kanamycin or hygromycin selection. Transgenic plants were phenotypically normal, showing a wide range of fluorescence levels, and were fertile. Expression of AmCyan, ZsGreen and AsRed was visible in maize T1 seeds, allowing visual segregation to more than 99% accuracy. The excitation and emission wavelengths of some of these proteins are significantly different; the difference is enough for the simultaneous visualization of cells transformed with more than one of the fluorescent proteins. These proteins will become useful tools for transformation optimization and other studies. The wide variety of plants successfully tested demonstrates that these proteins will potentially find broad use in plant biology.

The use of phosphomannose-isomerase as a selectable marker to recover transgenic maize plants (Zea mays L.) via Agrobacterium transformation.

A new selectable marker system has been adapted for use in Agrobacterium-mediated transformation of maize. This selection system utilizes the pmi gene encoding for phosphomannose-isomerase that converts mannose-6-phosphate to fructose-6-phosphate. Only transformed cells are capable of utilizing mannose as a carbon source. Agrobacterium-mediated transformation of immature embryos followed by a pre-selection of 10-14 days prior to selection at a level of 1% mannose and 0.5% sucrose led to the recovery of trangenic lines of a frequency of as high as 30% in about 12 weeks. Molecular and genetic analysis showed that selected plants contained the pmi gene and that the gene was transmitted to the progeny in a Mendelian fashion.

High-efficiency Agrobacterium-mediated transformation of Norway spruce (Picea abies) and loblolly pine (Pinus taeda).

Agrobacterium-mediated gene transfer is the method of choice for many plant biotechnology laboratories; however, large-scale use of this organism in conifer transformation has been limited by difficult propagation of explant material, selection efficiencies and low transformation frequency. We have analyzed co-cultivation conditions and different disarmed strains of Agrobacterium to improve transformation. Additional copies of virulence genes were added to three common disarmed strains. These extra virulence genes included either a constitutively active virG or extra copies of virG and virB, both from pTiBo542. In experiments with Norway spruce, we increased transformation efficiencies 1000-fold from initial experiments where little or no transient expression was detected. Over 100 transformed lines expressing the marker gene beta-glucuronidase (GUS) were generated from rapidly dividing embryogenic suspension-cultured cells co-cultivated with Agrobacterium. GUS activity was used to monitor transient expression and to further test lines selected on kanamycin-containing medium. In loblolly pine, transient expression increased 10-fold utilizing modified Agrobacterium strains. Agrobacterium-mediated gene transfer is a useful technique for large-scale generation of transgenic Norway spruce and may prove useful for other conifer species.

A double-blind randomized clinical trial on the effectiveness of a daily glycolic acid 5% formulation in the treatment of photoaging.

BACKGROUND: Low-strength daily formulations of glycolic acid are widely promoted for the treatment of photoaging. However, there are few clinical studies that objectively confirm the benefits of such formulations. OBJECTIVE: The purpose of this study was to determine the effectiveness of a 5% unneutralized formulation of glycolic acid in the treatment of facial and neck photoaging. METHODS: Seventy-five volunteers were recruited to take part in this double-blind randomized placebo-controlled clinical study. Participants applied either the 5% glycolic acid cream or the placebo cream to the face and neck for a period of 3 months. Pre- and posttreatment clinical assessments of photoaging effects were made by the same physician and were analyzed for statistical significance. RESULTS: Overall there were trends towards greater improvement or less worsening in the glycolic acid group for all clinical assessments for photoaging. There was statistically significant improvement favoring the active-cream in general skin texture and discoloration. There was a trend favoring glycolic acid in reduction of wrinkles, but this did not achieve statistical significance. CONCLUSION: Unneutralized 5% glycolic acid topical cream when used on a regular daily basis can improve some photoaging effects.

Frequent collinear long transfer of DNA inclusive of the whole binary vector during Agrobacterium-mediated transformation.

When Agrobacterium was used to transform Nicotiana plumbaginifolia protoplasts and Arabidopsis thaliana roots and seedlings, a large number of plants were found in which not only the T-region defined by the border repeat sequences but the entire binary vector was integrated, as determined by both PCR and Southern analysis techniques. N. plumbaginifolia protoplast co-cultivation experiments yielded 3 out of 5 transformants with collinear sequence past the left border. In Arabidopsis root transformation experiments, 33% (6/18) of the transformants had T-DNA which exceeded the left border repeat. Vacuum infiltration of Arabidopsis seedlings produced even a greater percentage of transformants with sequences outside the left border repeat (62%, 39/63). The long transfer DNA cosegregated with the T-region encoded hygromycin resistance in the T2 progeny eliminating the possibility that long transfer DNA was of extrachromosomal or Agrobacterium origin. The high frequency of long transfer after vacuum infiltration of A. thaliana needs to be considered when analyzing T-DNA tagged mutants.

Duplex Doppler measurements of renal blood flow in a dog with Addison's disease.

Abnormal intrarenal flow in a seven-year old female Tibetan terrier with Addison's disease was demonstrated by duplex Doppler examination. Abnormal flow may reflect renal vasoconstriction due to increased activity of the renin-angiotensin system. Although not pathognomonic, an increased resistive index (> 0.70) in an otherwise ultrasonographically normal kidney can be due to Addison's disease and the technique may prove valuable as a quick non-invasive tool in the management of this disease.

Large-scale protoplast isolation and regeneration of Arabidopsis thaliana.

A simple method for large-scale isolation and regeneration of Arabidopsis thaliana green protoplasts utilizing a novel starting material is presented. This technique takes advantage of shooty/embryogenic masses regenerating from fresh or cultured roots. There is no time-consuming mechanical isolation of starting material. Economical Bacto agar is used as an embedding agent. Plating efficiencies are between 5% and 10%. Seventy-six percent of protoplast-derived colonies produce shoots.

Estimates of components of variance of the rectal temperature in clinically healthy dogs in a hospital environment.

The rectal temperature is frequently measured in the morning on a daily basis in hospitalized dogs. Besides comparing the measured temperature to a population-based reference interval, it may also be of interest to evaluate the differences between consecutive measurements in order to follow the health status of a particular dog. In veterinary clinical chemistry, a parameter referred to as the critical difference, which can be used to judge if the difference between two consecutive measurements may be safely ascribed to random variation or not, has recently been introduced. The purpose of the present study was to obtain an estimate of the critical difference of the rectal temperature based on measurements of the rectal temperature in clinically healthy dogs in a hospital environment. The rectal temperature was measured in a standardized manner on 6 different days in 7 dogs. The total variance was estimated as 0.1015. The inter-individual variance was 0.0428, and the intra-analytical variance including the analytical variance was 0.0587. From these components of variance, the critical difference was calculated as 0.69 degrees C. Thus, the rectal temperature measured in the morning in hospitalized dogs can be expected to fluctuate about 0.7 degrees C from day to day due to random variation alone.

Evaluation of an automated spectrophotometric assay for the determination of total sialic acid in canine serum.

This study validates an automated enzymatic assay using the Cobas Fara (Roche) centrifugal analyser, which offers a reliable measurement of the total sialic acid concentration in canine serum as assessed by evaluating the precision and accuracy. Data are presented on the biological variation in the total serum sialic acid concentration. Measurements of total serum sialic acid concentration appear to be useful in distinguishing dogs with neoplastic disorders from clinically healthy dogs.

Comparison of results of haematological and clinical chemical analyses of blood samples obtained from the cephalic and external jugular veins in dogs.

The study was performed to investigate the difference in the concentration of several haematological and clinical chemical blood components in blood obtained from the cephalic and external jugular veins in 23 dogs. A total of 17 laboratory tests were analysed and, except for two clinical chemical blood components, there was no decisive difference in the test results obtained in blood samples collected from the cephalic and external jugular vein in dogs. For creatinine and potassium, however, there was a significant difference in the test results between the two veins, the highest results in general being measured in jugular venous blood. These findings indicate that it may be advisable to establish standardised procedures when collecting blood samples and make adjustments for the difference in test results when interpreting them.

Inhibition of somatic embryogenesis in orchardgrass by endogenous cytokinins.

Endogenous indoleacetic acid (IAA) and cytokinin concentrations were measured by high performance liquid chromatography in leaf sections of an orchardgrass (Dactylis glomerata L.) genotype which exhibited a high capacity for somatic embryogenesis in vitro and in two genotypes that did not exhibit this capacity. The nonembryogenic genotypes contained 3- to 4-fold higher concentrations of zeatin, zeatin riboside, dihydrozeatin, dihydrozeatin riboside, and total cytokinins than the embryogenic genotype. There were no significant differences in IAA concentrations between genotypes. Cytokinin concentrations between basal and distal sections of embryogenic genotype were not different, but the IAA concentration was significantly greater in basal sections. Somatic embryogenesis was inhibited in the embryogenic genotype by 0.001 micromolar exogenously added zeatin.