Immunohistochemistry of the extracellular matrix of the normal equine lamina cribrosa

Purpose To use immunohistochemical techniques to identify and localize the structural macromolecules of the extracellular matrix (ECM) of the normal adult equine lamina cribrosa in order to make comparisons to the extracellular matrix of the lamina cribrosa of horses with glaucoma. METHODS: Normal eyes of five adult horses between 5 and 10 years of age were fixed in 10% neutral buffered formalin and embedded in paraffin. Polyclonal rabbit-derived antibodies against human elastin, laminin, fibrillin-1, and collagen types I, III and IV, and polyclonal goat-derived antibodies against collagen type VI were used as primary antibodies. Transverse and longitudinal histologic sections of the optic nerve head and lamina cribrosa were stained using several dilutions of the primary antibodies, biotinylated link antibody, horseradish peroxidase-labeled streptavidin, and 3,3'-diaminobenzidine as a chromogen. The immunohistochemical staining patterns were qualitatively interpreted. RESULTS: The normal adult horse lamina cribrosa labeled positively for collagen types I, III and VI, laminin, elastin and fibrillin. Collagen type VI staining of the laminar ECM was most intense, followed by labeling for collagen types III and I, respectively. Laminar blood vessels were weakly positive for laminin and slightly positive for type IV collagen. The scleral ECM of the laminar insertion zone had more intense labeling for collagen types I and VI than did the laminar plates. CONCLUSIONS: The extracellular matrix of the laminar plates of the adult equine lamina cribrosa is similar to the dog as it consists of elastic and collagen fibers (with collagen types VI, III and I). Both the normal dog and horse lamina display more intense staining of collagen type VI than is found in the ECM of the normal human lamina cribrosa. The macromolecular structure of the equine lamina cribrosa suggests that it is a very resilient structure that may provide some protection to the optic nerve axons during episodes of elevated intraocular pressure.     

Potential of bumble bees as bio-vectors of Clonostachys rosea for Botrytis blight management in lowbush blueberry

The effectiveness of bees as vectors for microbial biological control agents has been demonstrated in greenhouses and some small-acreage crops. Less is known about the viability of this tactic for other cropping systems, or the effects of outfitting hives with dispensers on the bees. Experiments conducted in lowbush blueberry (Vaccinium angustifolium) fields indicated that home-made wooden, Koppert, and Enviroquest dispensers had no significant effects on foraging behavior or pollen loads of the bumble bee Bombus impatiens, but the presence of a dispenser did reduce the rate of workers exiting hives. Following exit of bees from dispensers, no difference was found in the quantity of the microbial agent Clonostachys rosea applied to the bees or blossoms, and distribution of product in the field was not influenced by dispenser design or distance from hives. However, the prevalence of the pathogen Botrytis cinerea in blossoms from cages that contained hives with dispensers with C. rosea was significantly less (10–20 %) than blossom infection in control plots, despite unseasonably inclement conditions and restricted foraging. These results suggest that C. rosea can be effectively delivered by commercial bumble bees for prevention of B. cinerea infection in V. angustifolium, but the efficacy of the technique will be limited during periods of poor weather that often occur in regions where lowbush blueberries are grown. Some technical issues with dispensers and commercial B. impatiens hives also need to be addressed before widespread use can be expected within commercial lowbush blueberry production.     

Down's syndrome in adults: brain metabolism

The cerebral metabolic rate for glucose, as measured with positron emission tomography and fluorine-18-labeled 2-deoxy-D-glucose, was significantly higher in four healthy young subjects with trisomy 21 syndrome (Down's syndrome) than the mean rate in healthy young controls. The rate of cerebral glucose utilization in the frontal lobe of a 51-year-old subject with Down's syndrome was significantly lower than the rate in the young subjects with this syndrome, but approximated the rate in middle-aged controls. Thus glucose utilization by the brain appears to be excessive in young adults with Down's syndrome but may decline with age in some brain regions.     

Paleontology and Chronology of Two Evolutionary Transitions by Hybridization in the Bahamian Land Snail Cerion

The late Quaternary fossil record of the Bahamian land snail Cerion on Great Inagua documents two transitions apparently resulting from hybridization. In the first, a localized modern population represents the hybrid descendants of a 13,000-year-old fossil form from the same area, introgressed with the modern form now characteristic of the adjacent regions. In the second case, a chronocline spanning 15,000 to 20,000 years and expressing the transition of an extinct fossil form to the modern form found on the south coast was documented by morphometry of fossils dated by amino acid racemization and radiocarbon. Hybrid intermediates persisted for many thousands of years.     

Volatiles from the 1994 Eruptions of Rabaul: Understanding Large Caldera Systems

The 1994 eruption of Rabaul, in Papua New Guinea, involved a small plinian eruption at Vulcan and a vulcanian eruption on the opposite side of the caldera at Tavurvur. Vulcan's ash leachates indicate seawater interaction that is consistent with earlier observations of low sulfur dioxide emissions and the presence of ice crystals in the initial plinian eruption cloud. In contrast, Tavurvur ash leachates indicate no seawater interaction, and later sulfur dioxide emissions remained high despite low-level eruptive activity. Silicic melt inclusions indicate that the andesitic melt contained about 2 weight percent water and negligible carbon dioxide. Mafic melt inclusions in Tavurvur ash have water and carbon dioxide contents that vary systematically over the course of the eruption. The mafic melt inclusions suggest that a mafic dike intruded from below the silicic chamber and provide further evidence that mafic intrusions drive caldera unrest.     

Radar detection of the nucleus and coma of comet hyakutake

Radar observations of comet Hyakutake (C/1996 B2) made at the Goldstone Deep Space Communications Complex in California have detected echoes from the nucleus and from large grains in the inner coma. The nucleus of this bright comet was estimated to be only 2 to 3 kilometers in diameter. Models of the coma echo indicate backscatter from porous, centimeter-size grains ejected anisotropically at velocities of tens of meters per second. The radar observations suggest that a comet's activity may be a poor indicator of its size and provide evidence that large grains constitute an important component of the mass loss from a typical active comet.     

Re-evaluation of the pharmacokinetics of xylazine administered to Thoroughbred horses

Xylazine is widely used worldwide as a short-acting sedative in general equine and racing practice. In the UK, although it has a legitimate use during training, equine anti-doping rules state it is a prohibited substance on race day. The aim of the study was to produce a detection time (DT) to better inform European veterinary surgeons so that xylazine can be used appropriately under regulatory rules. Previous publications have various limitations pertaining to analysis method, particularly for plasma and limited length of time of sample collection. In this study, pharmacokinetic data were produced for xylazine and 4-OH-xylazine in equine urine and plasma following a single intravenous xylazine dose of 0.4 mg/kg to six Thoroughbred horses. Pharmacokinetic parameters were generated from a 3-compartmental model with clearance = 15.8 ± 4.88 ml min^-1 kg^-1, Vss = 1.44 ± 0.38 L/kg, terminal half-life = 29.8 ± 12.7 hr and a DT determined at 71 hr for the administration of xylazine (Chanazine^®) in plasma and urine. Urine screening should aim to detect the 4-OH-xylazine metabolite, which can act as an indicator for the xylazine plasma concentration. A DT of 72 hr has been agreed by the European Horserace Scientific Liaison Committee, to be implemented in June 2019.