Live animal predictions of carcass components and marble score in beef cattle: model development and evaluation.

Until recently, beef carcass payment grids were predominantly based on weight and fatness categories with some adjustment for age, defined as number of adult teeth, to determine the price received by Australian beef producers for slaughter cattle. With the introduction of the Meat Standards Australia (MSA) grading system, the beef industry has moved towards payments that account for intramuscular fat (IMF) content (marble score (MarbSc)) and MSA grades. The possibility of a payment system based on lean meat yield (LMY, %) has also been raised. The BeefSpecs suite of tools has been developed to assist producers to meet current market specifications, specifically P8-rump fat and hot standard carcass weight (HCW). A series of equations have now been developed to partition empty body fat and fat-free weight into carcass fat-free mass (FFM) and fat mass (FM) and then into flesh FFM (FleshFFM) and flesh FM (FleshFM) to predict carcass components from live cattle assessments. These components then predict denuded lean (kg) and finally LMY (%) that contribute to emerging market specifications. The equations, along with the MarbSc equation, are described and then evaluated using two independent datasets. The decomposition of evaluation datasets demonstrates that error in prediction of HCW (kg), bone weight (BoneWt, kg), FleshFFM (kg), FleshFM (kg), MarbSc and chemical IMF percentage (ChemIMF%) is shown to be largely random error (%) in evaluation dataset 1, though error for ChemIMF% was primarily slope bias (%) in evaluation dataset 1, and BoneWt had substantial mean bias (%) in evaluation dataset 2. High modelling efficiencies of 0.97 and 0.95 for predicting HCW for evaluation datasets 1 and 2, respectively, suggest a high level of accuracy and precision in the prediction of HCW. The new outputs of the model are then described as to their role in estimating MSA index scores. The modelling system to partition chemical components of the empty body into carcass components is not dependent on the base modelling system used to derive empty body FFM and FM. This can be considered a general process that could be used with any appropriate model of body composition.

Methane emissions and airflow patterns on a longwall face: Potential influences from longwall gob permeability distributions on a bleederless longwall panel.

Longwall face ventilation is an important component of the overall coal mine ventilation system. Increased production rates due to higher-capacity mining equipment tend to also increase methane emission rates from the coal face, which must be diluted by the face ventilation. Increases in panel length, with some mines exceeding 6,100 m (20,000 ft), and panel width provide additional challenges to face ventilation designs. To assess the effectiveness of current face ventilation practices at a study site, a face monitoring study with continuous monitoring of methane concentrations and automated recording of longwall shearer activity was combined with a tracer gas test on a longwall face. The study was conducted at a U.S. longwall mine operating in a thick, bituminous coal seam and using a U-type, bleederless ventilation system. Multiple gob gas ventholes were located near the longwall face. These boreholes had some unusual design concepts, including a system of manifolds to modify borehole vacuum and flow and completion depths close to the horizon of the mined coalbed that enabled direct communication with the mine atmosphere. The mine operator also had the capacity to inject nitrogen into the longwall gob, which occurred during the monitoring study. The results show that emission rates on the longwall face showed a very limited increase in methane concentrations from headgate to tailgate despite the occurrence of methane delays during monitoring. Average face air velocities were 3.03 m/s (596 fpm) at shield 57 and 2.20 m/s (433 fpm) at shield 165. The time required for the sulfur hexafluoride (SF6) peak to occur at each monitoring location has been interpreted as being representative of the movement of the tracer slug. The rate of movement of the slug was much slower in reaching the first monitoring location at shield 57 compared with the other face locations. This lower rate of movement, compared with the main face ventilation, is thought to be the product of a flow path within and behind the shields that is moving in the general direction of the headgate to the tailgate. Barometric pressure variations were pronounced over the course of the study and varied on a diurnal basis.

Biochemical and biological activities of 2,3-dihydro-6-[3-(2-hydroxymethyl)phenyl-2-propenyl]-5-benzofuranol (L-651,896), a novel topical anti-inflammatory agent.

The biochemical and biological profile of a topical anti-inflammatory agent, 2,3-dihydro-6-[3-(2-hydroxymethyl)phenyl-2-propenyl]-5-benzofuranol (L-651,896 inhibited the 5-lipoxygenase of rat basophilic leukemia cells with an IC50 of 0.1 microM and leukotriene synthesis by human PMN and mouse macrophages with IC50 values of 0.4 and 0.1 microM respectively. L-651,896 also inhibited prostaglandin E2 synthesis by mouse peritoneal macrophages (IC50 = 1.1 microM). This compound inhibited ram seminal vesicle cyclooxygenase activity at considerably higher concentrations, and this effect was directly related to substrate concentration. When applied topically to the mouse ear, L-651,896 lowered elevated levels of leukotrienes associated with arachidonic acid-induced skin inflammation and delayed hypersensitivity induced by oxazolone. However, while L-651,896 inhibited the increased vascular permeability induced by arachidonic acid, it had no effect on the edema associated with the immune-based response to oxazolone in the same tissue. Thus, it is possible that leukotrienes may play a role in some but not all inflammatory responses.

Synthesis and antiinflammatory/analgesic activities of 11H-dibenzo[b, e,][1,4]dioxepinacetic acids.

A new class of tricyclic arylacetic acids was synthesized and evaluated as antiinflammatory/analgesic agents as well as inhibitors of prostaglandin synthetase. 11H-Dibenzo[b,e][1,4]dioxepin-2-, -3, -7, and -8-acetic and alpha-methylacetic acids and their derivatives were prepared by cyclization of diaryl ether precursors or by condensation of catechol and an aryl dihalide. The most potent compound in the carrageenan foot edema assay was alpha-methyl-11H-dibenzo[b,e][1,4]dioxepin-8-acetic acid (1 mg/kg = 43% inhibition). The most potent enzyme inhibitors were the 2-acetic acid and the alpha-methyl-7-acetic acid (IC50 = 0.1 microM). Some of these compounds were also found to be highly ulcerogenic.

Adrenal cyst.

Adrenal cysts are rare lesions that usually present as incidental findings during surgery or at the time of autopsy. The cysts are usually small, seldom exceeding 10 cm in diameter, and are generally asymptomatic. In those few cases that are symptomatic, radiographic examination is the most important tool in establishing a correct preoperative diagnosis. Of the four main categories, endothelial cysts represent the most common type of adrenal cyst. Simple surgical enucleation of the cyst, with preservation of the remaining adrenal gland, is the treatment of choice.

2-[3-(1,1-Dimethylethyl)-5-methoxyphenyloxazolo[4,5-b]pyridine, a new topical antiinflammatory and analgesic compound lacking systemic activity and gastric side effects.

The substituted oxazolopyridine 2-[3-(1,1-dimethylethyl)-5-methoxyphenyl]oxazolo[4,5-b]pyridine (OZP) inhibits phorbol myristate acetate-induced increases in vascular permeability and neutrophil accumulation in rat ears with ED50 of 253 and 200 micrograms, respectively. This compound is as potent as indomethacin to inhibit UV-induced erythema in guinea pig skin and is an effective analgesic when applied topically to the rat footpad in the yeast hyperalgesia model. OZP is a cyclooxygenase inhibitor with an IC50 of 0.06 mumol/l and inhibits prostaglandin E2, but not leukotriene C4 synthesis, by mouse peritoneal macrophages. This compound is inactive in the carrageenan paw edema assay at 90 mg/kg when administered orally or intraperitoneally, but is effective when injected into the paw. OZP is not a contact allergen and does not cause gastric irritation in rats at doses up to 180 mg/kg orally. OZP is rapidly metabolized by rat liver microsomes in a concentration and time dependent manner. Furthermore, when administered orally, OZP is cleared rapidly in rats with plasma levels being detected only at 5 and 30 min following a 2 mg/kg dose. There was no drug in the gastrointestinal tract of rats 3 h after an oral dose. Thus, this compound appears to be a new, potent and safe topical antiinflammatory and an analgesic agent lacking systemic effects.

Inhibition by prostaglandins of leukotriene B4 release from activated neutrophils.

Chemoattractant N-formylmethionylleucylphenylalanine (fMet-Leu-Phe) in the presence of cytochalasin B stimulates the release of leukotriene B4 (LTB4), superoxide (O2-), and N-acetylglucosaminidase from elicited rat peritoneal and human peripheral neutrophils [PMN (polymorphonuclear leukocytes)]. Prostaglandins E1 and E2 (PGE1 and PGE2) inhibit LTB4 release from PMN in a dose-related manner with an IC50 of 1 X 10(-8) M. This action is associated with increased levels of cyclic AMP. The inhibitory activity of a variety of PGs on LTB4 production by rat peritoneal PMN parallels their affinity for PGE receptors in other tissues. O2- release is also suppressed by low levels of PGE1 and PGE2 in a dose-related manner and this inhibition is enhanced by theophylline. In contrast, lysosomal enzyme release is only minimally affected by physiological levels of PGs. These data are consistent with an action of PGs at the level of the PG receptor on LTB4 and O2- release from the fMet-Leu-Phe-stimulated rat peritoneal PMN. In addition, the fMet-Leu-Phe-induced adherence of PMN to endothelial cells and inhibition of this phenomenon by PGs may now be explained by PG-mediated inhibition of LTB4 formation.

Evaluation of free radical scavengers in studies of lymphocyte-mediated cytolysis.

Oxygen centered radicals derived from potassium superoxide (KO2) in solution were found to be toxic to P815 mastocytoma target cells. Protection of P815 cells from chemically generated radicals was mediated most efficiently by Tiron, a low molecular weight scavenger of superoxide radicals (O2-). Superoxide dismutase (SOD) and catalase also afforded protection. In vivo cytolysis of P815 target cells mediated by allogeneic lymphocytes sensitized in vivo to tumor cells was inhibited by reducing the amount of oxygen available for metabolism and by radical scavengers. Ferricytochrome c, Tiron, and phenol, all of which are relatively low molecular weight radical scavengers, inhibited cytolysis in a dose-dependent manner, while mannitol, a hydroxyl radical scavenger, did not. High molecular weight scavengers like SOD and catalase had no effect. The inhibition of cytolysis by radical scavengers was found to be independent of toxic effects on effector cells, chelation of ions, or indirect effects on prostaglandin biosynthesis. Pretreatment of either effector or target cells with Tiron had no effect on LMC. The data suggest a possible role for free radicals in molecular events leading to target cell injury by sensitized lymphocytes.