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The dipeptide carnosine consists of β-alanine and L-histidine. It plays a major role in skeletal muscle metabolism, especially as an intracellular buffer and antioxidant. Increasing intramuscular carnosine has been shown to improve recovery from exercise and increase anaerobic threshold and time-to-exhaustion. Dietary supplementation with carnosine does not effectively increase intramuscular carnosine due to the presence of carnosinase in the blood. However, an effective transdermal delivery process could expediently increase intramuscular concentrations of carnosine. This study’s objective was to examine the efficacy of a transdermal system for delivering carnosine into the skeletal muscle of horses, using a randomised, placebo controlled, crossover study. Carnosine plus a proprietary transdermal delivery agent or the agent alone (placebo) were applied to the middle gluteal muscles of 10 Thoroughbred racehorses, and muscle biopsies were taken before and 30, 60, and 120 min after application. Muscle carnosine concentration was measured using an enzyme-linked immunosorbent assay. A two-way repeated measures analysis of variance was used to test for the main effects of time and treatment (placebo or carnosine) as well as an interaction between time and treatment. Independent F-tests examined the change in intramuscular carnosine levels from baseline to each time point (30, 60, and 120 min). There was a significant main effect of treatment (P=0.004), no significant main effect for time (P=0.18), and a non-significant interaction of treatment with time (P=0.08). Mean intramuscular carnosine concentrations increased from baseline to 120 min. Compared to concentrations following placebo application, carnosine was greater by ~35% at 30 min (P=0.002) and ~46% after 60 min (P=0.044), but not at 120 min (P=0.20). The results indicated that intramuscular carnosine can be increased using a transdermal delivery system within 60 min of application which could have important implications for the health of horses, and their capacity to perform and recover from physical activity.

The authors explored the potentials of using both neutron and gamma-ray measurements on a single item and combining these data into a single assay value. The purpose was to improve assay capability for sample matrices that are difficult to measure. They chose an empirical approach because they wanted to address difficult-to-measure items for which the assay problem is complex. They used the tomographic gamma scanner; a passive, high-efficiency neutron counter with add-a-source and multiplicity; and an active neutron, californium shuffler to obtain measurements. Twenty-four 200-L drums were measured with various matrices using all three machines. The matrices were chosen specifically to spain the difficult-to-measure assay problems for some or all of the instruments. For example, the authors measured a drum filled with concrete and another filled with metal. The data from these measurements were analyzed using the alternating conditional expectation algorithm, which is one of a class of generalized additive models. Other data fusion algorithms are also possible and are being explored. The intent was to find ways to combine the data that would reduce the matrix-induced measurement error.

A nitroindanedione (BRL 10833) inhibited the antigen induced release of histamine and slow reacting substance of anaphylaxis (SRS-A) from passively sensitized human lung at similar concentrations to those required for the inhibition of histamine release by disodium cromoglycate (DSCG). BRL 10833 was more potent than DSCG as an inhibitor of histamine release by antigen from actively and passively sensitized rat peritoneal cells and rat skin fragments.

Passive peritoneal anaphylaxis in rats, sensitised with mouse antiserum, had characteristics of an IgE-mediated reaction, in that the serum was heat-labile and pretreatment of the rats with disodium cromoglycate (DSCG), or sodium nivimedone, inhibited the release of both histamine and slow-reacting substance of anaphylaxis (SRS-A). Sodium nivimedone was more potent than DSCG as an inhibitor of histamine release. Peak concentrations of histamine and SRS-A in the peritoneal fluids of the rats, were reached within 2 min of antigen challenge and fell to control levels after 20–30 min.

When actively sensitised rats were injected intraperitoneally with antigen, the local reaction that ensued can be divided into two phases: an immediate reaction characterised by histamine and SRS-A release with an associated extravasation of plasma proteins, and a late reaction involving infiltration of neutrophilic polymorphonuclear leucocytes. When the immediate reaction was modified by BRL 10833 (which inhibits histamine release from rat mast cells and reduces extravasation of plasma proteins), there was no reduction in neutrophil infiltration. FPL 55712, an SRS-A antagonist, also failed to inhibit neutrophil infiltration. The β-adrenoreceptor stimulants isoprenaline and salbutamol reduced neutrophil infiltration. Isoprenaline inhibited the extravasation of plasma proteins when given before antigen, but even when administered to rats after antigen, when extravasation was complete, it still inhibited neutrophil infiltration. Propranolol reversed isoprenaline-induced inhibition of neutrophil infiltration.

Rats actively sensitised to bovine serum albumin (BSA) in Freund’s complete adjuvant were challenged by intraperitoneal injection of BSA. By washing out the peritoneal cavities at different times it was possible to divide the changes that occurred into two phases. The first was characterised by the release of histamine and slow reacting substance of anaphylaxis (SRS-A) with an associated extravasation of plasma proteins. The second phase was characterised by an increase in neutrophilic polymorphonuclear cells in the peritoneal cavity. Extracellular enzyme activities were also investigated. The kinetics of these events were studied and are discussed in terms of the possible mechanisms involved.