Implementation of a safety resheathable winged steel needle substantially reduced injuries among healthcare workers performing vascular-access procedures. The residual risk of injury associated with this device can be reduced further with increased compliance with proper activation procedures.

Twenty-four lambs grazing pastures of Panicum coloratum developed photosensitization secondary to hepatic dysfunction. Lesions were necrosis of scattered hepatocytes, obstruction of small bile ducts and bile canaliculi by small aggregates of birefringent crystals, and accumulation of birefringent crystals in phagocytes within sinusoids. The number of crystals in livers of affected sheep varied, depending on the amount of time of exposure to toxic plants and severity of hepatic abnormalities. Crystals in the liver were soluble in acidified ethyl alcohol, acetic acid, pyridine, chloral hydrate, and methanol, but not in xylene, petroleum ether, diethyl ether, acetone, water, or cold ethyl alcohol. Crystals were not stained by oil red O. There was necrosis of epithelial cells in renal distal convoluted tubules, papillary muscles of the heart, and the adrenal cortex. Lesions of Panicum coloratum-associated disease are similar to those associated with photosensitization induced by Tribulus terrestris, Agave lecheguilla, and Nolina texana.

An experiment was conducted to investigate the compartmental mean residence time, (CMRT) of feed residues in segments of gastrointestinal digesta of mature Holstein steers. The objective was to evaluate assumptions that feed residues flow through ruminal digesta as sequential mixing pools having age-dependent (GN) and age-independent (G1) distributed residence times respectively (GN → G1 flow). The basal diet was a semi-tropical hay containing 98 g crude protein and 503 g apparently digestible DM per kg DM. The hay was consumed and feed residues of different size and/or previous digestion from the hay were inserted into the reticulo-rumen (rumen) and abomasum. Marker profiles appearing at the duodenum and faeces were fitted to various compartment models to estimate CMRT. Post-abomasal CMRT did not differ among solutes or feed residues of different size and previous digestion and constituted only 5⋅8 % of the CMRT for the entire gastrointestinal tract. Markers initially applied to orally or ruminally dosed feed residues exhibited profiles in duodenal digesta and faeces conforming to GN → G1 flow. Previously undigested, masticated feed residues inserted into the dorsal rumen digesta had longer ruminal CMRT in the GN pool but not the G1 pool than did similarly inserted faecal small particles or normally ingested hay. These results support model assumptions of GN → G1 flow within rumen digesta. The results support mechanisms proposed for the GN pool as the 'lagrumination pool' and the G1 pool as the 'mass action turnover pool'. If further validated, rumen CMRT in cattle could be estimated from marker profiles in more easily obtained faeces to estimate ruminal CMRT required for feed evaluation systems. Compartmental models: Digesta flow: Forage particle sizeThe compartmental mean residence time (CMRT) of feed residues in the digesta of the reticulo-rumen (rumen) is determined by various forces that constrain and propel ruminal escape of undigested feed residues. A major force constraining escape is the competition among ingested feed residues with resident residues of previous meals as the result of the continual mixing of ruminal digesta. If this competition for escape is passive for all feed residues, regardless of their attributes or age in the pool, then CMRT is a function of the mass of resident feed residues and the continued intake rate of feed residues, i.e. mass action dilution turnover rate of the continued intake. Matis (1972) observed that newly ingested feed residues require ageing before acquiring properties required for escape, properties such as particle size reduction for example. Matis (1972) proposed an age-dependent distribution of residence times to model this initial process constraining escape in contrast to an age-independent, mass action turnover. The age-dependent turnover of undigested feed residues in ruminal digesta could be modelled as a single agedependent mixing pool or a sequence of age-dependent → age-independent mixing pools. Ellis et al. (1991Ellis et al. ( , 1994 proposed the 'un-...

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