Two experiments were carried out to determine endogenous excretion of purine derivatives in steers and lambs, and to investigate the relationship between microbial nucleic acid input and urinary excretion of purine nitrogen.The endogenous excretion of allantoin after conversion of hypoxanthine, xanthine and uric acid to allantoin, was calculated to be 72 and 26 mg/kg W 075 per day in steers and lambs, respectively, when the dietary protein contained no nucleic acid nitrogen.The excretion of purine derivatives increased linearly with increasing microbial nucleic acid input in lambs. The excretion of purine derivatives in excess of endogenous contribution was closely related to the theoretically expected values. The average recovery was calculated as 0-96 for one sheep and 1-0 for the other.

Conservation genetics focuses on the effects of contemporary genetic structuring on long-term survival of a species. It helps wildlife managers protect biodiversity by identifying a series of conservation units, which include species, evolutionarily significant units (ESUs), management units (MUs), action units (AUs), and family nets (FNs). Although mitochondrial DNA (mtDNA) evolves 5-10 times faster than single-copy nuclear DNA (scnDNA), it records few traces of contemporary events. Thus, mtDNA can be used to resolve taxonomic uncertainties and ESUs. Variable number of tandem repeats (VNTRs) evolve 100-1000 times faster than scnDNA and provide a powerful tool for analyzing recent and contemporary events. VNTR analysis techniques include polymerase chain reaction (PCR)-based microsatellite assays and oligonucleotide probing. Size homoplasy problems in PCR-based microsatellite assays can strongly affect the inference of recent population history. The high homozygosity in endangered species is reflected in a relatively low number and level of variability in microsatellite loci. This combined with "allelic dropout" and "misprinting" errors contributes to the generation of highly biased genetic data following analyses of natural populations. Thus, in conservation genetics, microsatellites are of limited use for identifying ESUs, MUs, and AUs. In contrast to PCR-based microsatellite analysis, oligonucleotide probing avoids errors resulting from PCR amplification. It is particularly suitable for inferring recent population history and contemporary gene flow between fragmented subpopulations. Oligonucleotide fingerprinting generates individual-specific DNA banding patterns and thus provides a highly precise tool for monitoring demography of natural populations. Hence, DNA fingerprinting is powerful for distinguishing ESUs, MUs, AUs, and FNs. The use of oligonucleotide fingerprinting and fecal DNA is opening new areas for conservation genetics.

No abstract

No abstract

Purpose: To compare conjunctival epithelium expression of HLA-DR and ICAM-1 with tear dynamics and ocular surface parameters. Methods: Brush cytology and flow cytometry were used to quantitatively analyze HLA-DR and ICAM-1 expression in 28 dry eye patients. Results: HLA-DR was expressed in 66% of the conjunctival cells of dry eye patients. This expression correlates with that of ICAM-1, as well as with the Schirmer test results (p < 0.05). Conclusion: This study confirmed that dry eye consists not only of ocular surface desiccation, but also of upregulation of the HLA-DR and ICAM-1 molecule in the conjunctival epithelium, possibly resulting in increased inflammation.

Lactoferrin inhibits bacterial growth in the conjunctival sac. However, its antiviral function particularly in ocular tissue has not been reported in the literature. We studied whether lactoferrin inhibits infection of herpes simplex virus type-1 (HSV-1) in vitro using Vero cell monolayer. We also tested the inhibitory effect of lactoferrin on HSV-1 infection in the mouse cornea. Lactoferrin prevented HSV-1 plaque formation. Administration of topical 1% lactoferrin prior to the virus inoculation suppressed infection on ocular tissue, however it did not inhibit propagation of the virus.

No abstract

The dry eye syndrome is a chronic disease which can become a serious threat to useful vision. However, there is only a limited understanding regarding effective treatment or prevention of this disease. Establishing an effective mode of treatment requires the use of a satisfactory animal dry eye model. Ideally, such a model should rapidly determine the effectiveness of agents that inhibit the damaging effects of this syndrome. This paper presents a short-term dry eye model using rabbits, which combines mechanical prevention of blinking and methylene blue staining. This model is not intended to be a precise representation of the dry eye syndrome, since this disorder has recently become recognized to involve a primary pathological process of the corneal and conjunctival epithelium. However, by using this model, clinical signs of dry eye can be observed after a few hours in the form of acute desiccation. Corneal damage can easily be evaluated both qualitatively by methylene blue staining scores, and quantitatively by chronic assay. Visually observed corneal epithelial thinning was confirmed by scanning electron microscopy (SEM) to be due to loss of epithelial integrity. Using a 3% chondroitin sulfate solution, an already proven effective agent for dry eye, this model effectively demonstrated an 80% inhibition in the development of methylene blue positive lesion after a period of only 2 hours. This short term dry eye model is valuable in primarily screening the efficacy of potential therapeutic agents in the prevention and treatment of dry eye.