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.     

C, N, and noble gas isotopes in grain size separates of presolar diamonds from efremovka

Nanometer-size presolar diamonds from the Efremovka CV3 chondrite were physically separated into several grain size fractions by ultracentrifugation. The coarsest size fraction is the most enriched in carbon-12; the others have broadly similar carbon isotopic compositions. Measurement of noble gases shows that their concentration decreases with decreasing grain size. This effect is attributed to ion implantation. Such an episode could occur in the envelope of a supernova that produced the diamonds, or in interstellar space; in either case, ions with energies above a certain threshold pass completely through the smaller diamond grains without being captured. Concentrations of nitrogen show only minor variations with grain size, indicating a different mechanism of incorporation into the diamonds.     

Successful long term treatment of a dog with psychomotor seizures using carbamazepine

Psychomotor seizures (temporal lobe epilepsy) were diagnosed in a dog based on history, clinical findings and electroencephalography. Long-term seizure control was achieved with carbamazepine, despite serum drug concentrations which were low to unmeasurable. It is suggested that serum levels of carbamazepine are not a useful guide to clinical efficacy in the dog, that an unmeasured metabolite of carbamazepine may account for the anti-convulsant activity and that carbamazepine may be potentially useful in treating certain canine seizure disorders.     

Paralysis and lipofuscin-like pigmentation of farm stock caused by the plant, Trachyandra laxa var. laxa

A paralytic condition of farm stock in South West Africa, characterized by prominent neuronal and some mild extraneuronal pigmentation, is described. The distribution of the pigment, which was mainly located in the larger neurones of the brain and spinal cord, is given. Experimental evidence, obtained by feeding the plant, is presented that the condition is caused by Trachyandra laxa var. laxa. The histochemical features of the pigment proved to be compatible with a lipofuscin.     

CASE REPORT AND CLINICAL REVIEW: Unilateral facial myokymia in a dog with an intracranial meningioma

A 23-month-old castrated male Cavalier King Charles spaniel was evaluated because of a 6-month history of unusual rippling/undulating movements of the right facial muscles that were continuous and persisted during sleep. Neurological examination revealed narrowing of the right palpebral fissure and unilateral right-sided facial myokymia that was characterised by myokymic, and to a lesser degree, neuromyotonic discharges on concentric needle electromyographic examination. After persisting unchanged for almost 2.5 years from its onset, the facial myokymia gradually disappeared over a 6-month period concomitant with the emergence of a persistent ipsilateral facial paralysis and head tilt. At 5 years and 9 months after the first examination, signs of ipsilateral lacrimal, pharyngeal and laryngeal dysfunction became evident and the dog was euthanased. Postmortem examination identified a malignant (WHO grade III) meningioma in the right cerebellopontomedullary angle that compressed the ventrolateral cranial medulla, effaced the jugular foramen and internal acoustic meatus and extended into the facial canal of the petrous temporal bone. Novel findings were the unique observation of isolated unilateral facial myokymia preceding diagnosis of a meningioma affecting facial nerve function within the caudal cranial fossa and the remarkably long duration of neurological signs (75 months) attributable to the neoplasm.