Cell Cycle Stage Analysis of Rabbit Foetal Fibroblasts and Cumulus Cells

Synchronization of the cell cycle stages in G0/G1 phase is one of the key factors determining the success of nuclear transplantation. Serum deprivation, contact inhibition and chemical inhibitors are widely used methods for this purpose. In this study, cell cycle stages of foetal fibroblasts and cumulus cells were determined using flow cytometry [fluorescence-activated cell scan (FACS)]. Foetal fibroblasts (in vitro cultured for 72-120 h) and fresh cumulus cells were analysed in Experiment 1. Fifty to 55% proliferating fibroblasts remained in G0/G1 phase compared with 78% in confluent culture (p <0.05). In contrast to foetal fibroblasts, fresh cumulus cells maintained 90% of the population in the G0/G1 stage. When serum was retrieved from the proliferating fibroblasts from day 1 to day 5 (Experiment 2), proportions of G0/G1 cells increased from the initial ratio of 53 to 87% at day 4 of starvation, which was significantly higher than the non-starved proliferating cells (p <0.05). In Experiment 3, fibroblasts were treated with aphidicolin (0.1 microg/ml, 6 h), demicolcine (0.5 microg/ml, 10 h), or a combination of these two chemicals to synchronize the cell cycle stages. Surprisingly, no differences or significantly lower in the proportions of G0/G1)phase cells were detected (25-50%) compared with the uncontrolled growing cells (53%). These results suggested that fresh cumulus cells rest their cell cycle in G0/G1 stage. Serum deprivation became effective in the first 24 h and reached the highest proportions during days 4-5 after deprivation. Chemical synchronization of the cell cycle stage of rabbit foetal fibroblasts to G0/G1 phase appeared less effective compared to serum deprivation.     

The adsorption and degradation of glyphosate in five Hawaiian sugarcane soils*

The rate of aerobic evolution of ¹⁴CO₂ from ¹⁴C-glyphosate labelled in the methylphosphonyl carbon, varied 100-fold within a group of five Hawaiian sugarcane soils. The rate depended inversely on the degree of soil binding, probably associated with the phosphonic acid moiety, and to a less certain extent on soil pH and soil organic matter. After an initial rapid degradation, the rate of ¹⁴CO₂ evolution in three soils reached a constant at 16–21 days which continued to the 60-day termination. The other two soils showed a continually decreasing rate throughout. Two soils released over 50% of the labelled carbon in 60 days, a third released 35%, while the remaining soils released 1.2 and 0.8% respectively. Labelled carbon in the soils after 60 days consisted of glyphosate and one metabolite, aminomethyl-phosphonic acid, with glyphosate predominating in high fixing soils. The ¹⁴C could be extracted almost completely with NaOH solution, and remained mainly in solution after acidification.     

Influence of dietary selenium on the occurrence of nephrocalcinosis in the rainbow trout, Salmo gairdneri Richardson

Abstract Rainbow trout were fed practical-type diets containing 0.6, 6.6 and 114 μ g/g selenium for 16 weeks at approximately 15°C. Fish reared on the highest levels of dietary selenium had a significant reduction in final body weight, feed: gain ratio and increased mortality. Haematocrit, plasma calcium, glucose, and protein levels did not vary significantly. Ninety per cent of the fish fed the diet containing the highest level of selenium developed nephrocalcinosis. Fish with occult nephrocalcinosis had significantly increased levels of kidney calcium and those with overt nephrocalcinosis had significantly increased levels of kidney calcium and magnesium, and liver magnesium. Microscopically, the majority of renal damage was tubular with the renal interstitium becoming inflamed only when tubules degenerated. The pathogenesis of selenium-induced nephrocalcinosis is discussed.     

Solarization for the control of Pueraria montana (kudzu)

The effects of translucent polyethylene sheeting as a thermal covering to eradicate Pueraria montana (kudzu) were investigated at Clemson, South Carolina on a clay loam. In 2005, the highest reduction of live root crowns was observed where P. montana was covered for the entire growing season (May–October) with a reduction of 42% of live root crowns compared with the control plots. Where P. montana was covered for alternate weeks throughout the growing season live root crowns were reduced by 35%. Covering P. montana for one week and then uncovering for four weeks repeatedly through the season killed 24% of root crowns. In 2006, the second year of treatment to the same plots, the three solarization treatments had similar efficacy of about 97%. The use of polyethylene sheeting appears not to be cost‐effective for general control of large P. montana infestations, but may be useful for small patches.     

THE COMPUTED TOMOGRAPHIC APPEARANCE OF EQUINE TEMPOROHYOID OSTEOARTHROPATHY

Equine temporohyoid osteoarthropathy is characterized by progressive osseous proliferation of the temporohyoid articulation and surrounding structures. The diagnosis has generally been made using radiography and endoscopy of the guttural pouch. Recently, computed tomography (CT) has been used in the diagnosis of temporohyoid osteoarthropathy. This study was performed to determine the CT imaging characteristics of temporohyoid osteoarthropathy and to compare these to radiographic and endoscopic findings. CT scans from 16 horses with a final diagnosis of temporohyoid osteoarthropathy were reviewed. Five horses that had undergone CT scan for reasons other than temporohyoid osteoarthropathy were included as controls. Qualitative and quantitative data were used to describe the magnitude of the CT findings. Osseous proliferation of the stylohyoid bone and temporohyoid articulation was found to be a consistent feature of temporohyoid osteoarthropathy. Thickening of the ceratohyoid bone and proliferation of its articulation with the stylohyoid bone was frequently identified and this finding may have surgical implications. Horses with neurologic deficits had increased stylohyoid width that was significantly different than the subclinically affected side. CT evaluation also allowed the identification of subclinical bilateral disease in horses thought to be unilaterally affected based on clinical examination.