A re-evaluation of the anxiolytic properties of intramuscular midazolam

The observed effect of midazolam on anxiety is equivocal in part because previous studies have not ruled out pre-treatment differences in anxiety scores between patients who received midazolam and those who did not (controls). This study re-examines the anxiolytic effect of premedication with intramuscular midazolam using a sample size calculated to be of sufficient size to rule out population differences as a variable affecting treatment results. In the midazolam group (n = 49) anxiety scores were determined prior to administration of midazolam 0.07 mg/kg intramuscularly, and again 60 minutes later. In the control group (n = 47) anxiety scores were determined prior to intramuscular injection of a similar volume of matching placebo (midazolam vehicle), and again 60 minutes later. No differences in anxiety scores between groups either before treatments or 60 minutes after treatments were observed. Within both groups, anxiety scores at 60 minutes were no different from pre-treatment scores. In this study midazolam did not produce a statistically significant decrease in pre-operative anxiety scores at 60 minutes following intramuscular administration.

Inhibition of macrophage activation by calcium channel blockers and calmodulin antagonists

The biochemical mechanisms by which macrophages become activated to the tumoricidal state are poorly understood. To investigate the role of calcium in this process, the effect of calcium channel blockers and calmodulin antagonists on the acquisition of tumoricidal properties by macrophages activated by a number of different agents was examined. Activation of thioglycollate-stimulated C57BL/6 mouse peritoneal macrophages by macrophage activation factor (MAF) plus LPS, IFN-gamma plus LPS or the calcium ionophore, A23187, was inhibited in a dose-dependent fashion by the calcium channel blockers nifedipine and verapamil. These agents blocked the influx of 45Ca into macrophages activated by MAF plus LPS. Macrophage activation was also inhibited by chlorpromazine, W-7, and calmidazolium at concentrations known to perturb calmodulin function. The data suggest that activation of macrophages to the tumoricidal state is a calcium-dependent process involving the participation of calcium-regulated biochemical reactions whose activities can be modulated by pharmacological agents that frustrate transmembrane calcium fluxes and/or inhibit calmodulin function.

Ocular changes in a cat with disseminated blastomycosis

A domestic shorthair cat examined because of dyspnea was found to have ophthalmoscopic and radiographic changes suggestive of systemic mycosis. The cat died despite antifungal therapy. Histologic examination revealed Blastomyces dermatitidis in the eyes, brain, lungs, stomach, liver, kidneys, spleen, pancreas, and adrenal glands. The pathologic changes were similar, but more widespread than those typically seen with canine blastomycosis.

A role for hemolysin in Escherichia coli-induced inflammation in granulocytopenic rabbits

Inflammation induced in the skin of granulocytopenic rabbits by Escherichia coli was examined. Protein exudation and platelet deposition in lesions were measured with 125I-labeled albumin and 111In-labeled platelets. In granulocytopenic rabbits 10(4)-10(7) live serum-resistant E. coli induced protein exudation and platelet deposition beginning at 3 hr and then progressing over the next 24 hr to much higher levels than in normal rabbits. These responses were associated with interstitial edema and progressive venous thrombosis in the absence of leukocytes; no such reactions were observed in normal rabbits. No reactions were induced in granulocytopenic rabbits by killed E. coli. Of six E. coli strains tested, all three hemolytic strains induced lesions with four to five times more thrombosis (platelet deposition) than did nonhemolytic strains. Two hemolysin-negative mutants lost most of their thrombogenic activity. All three hemolytic strains had cell-associated hemolysin, but only one of these elaborated appreciable free, filterable hemolysin as well.

Inhibition of macrophage activation and tumor cell cytolysis by cyclosporin-A

Cyclosporin (CsA)4, a fungal peptide used clinically for its immunosuppressive properties, was investigated for its ability to antagonize the activation of macrophages (PEM) to the tumoricidal state. The acquisition of tumoricidal properties by PEM challenged with macrophage activating factor (MAF) plus lipopolysaccharide (LPS) was inhibited in a dose-dependent fashion by CsA. Similarly, CsA antagonized activation of PEM exposed to the calcium ionophore, A23187. CsA also inhibited macrophage-mediated tumor cell cytolysis in a dose-dependent manner. These data indicate that in vitro, CsA can modulate directly the acquisition and expression of tumoricidal properties by PEM and suggests that the macrophage may be an important target cell for CsA in vivo.

Characterization and immunocytochemical application of monoclonal antibodies against enkephalins

Monoclonal antibodies were produced following immunization of mice with either [Leu5]enkephalin-bovine serum albumin or [Met5]enkephalin-keyhold limpet hemocyanin conjugates. Two monoclonal antibodies coded NOC1 and NOC2, respectively, were derived. These monoclonal antibodies did not discriminate between Leu- and Met-enkephalin in either radioimmunoassay or immunocytochemistry. NOC1 was characterized in detail. In radioimmunoassay NOC1 displayed about 40% crossreactivity with C-terminal extended Met-enkephalin hexapeptides and 7% with the extended heptapeptide (-Arg-Phe-OH), but did not recognize other endogenous peptides. In immunocytochemistry the NOC1 and NOC2 recognized all well-established "enkephalin immunoreactive sites," but they did not bind to areas known to contain beta-endorphin or high levels of pro-enkephalin. NOC1 was shown to be a suitable tool to demonstrate enkephalin immunoreactive sites by radioimmunocytochemistry utilizing both internally and externally labeled monoclonal antibodies.

Development and application of a monoclonal rat peroxidase antiperoxidase (PAP) immunocytochemical reagent

Monoclonal antibodies are being increasingly used in immunocytochemistry but their localisation by the peroxidase antiperoxidase (PAP) procedure requires the use of rat or mouse PAP. In this paper we describe the development and application of a monoclonal rat PAP. This reagent has been used successfully for immunocytochemistry at light and electron microscopy level in combination with rat monoclonal antibodies against serotonin (5-HT), substance P and somatostatin. The monoclonal rat PAP has several advantages over conventional polyclonal rat PAP and is likely to be a valuable developing reagent in immunocytochemistry using rat monoclonal antibodies.

The alloantigenic organization of RT1Aa, a class I major histocompatibility complex molecule of the rat

Over 300 monoclonal IgG alloantibodies have been prepared against RT1Aa , the class I major histocompatibility complex molecule of the DA rat. In this study a combination of techniques is exploited to show that all these antibodies can be allocated to 9 antigenic sites which form a continuous antigenic surface, that is, no site is completely isolated from the rest. The results suggest that techniques for the identification of antigenic sites using competitive inhibition of monoclonal antibody binding are generally valid, in the sense that competition between antibodies appears most commonly to represent competition between combining sites for a structural feature of the antigenic surface. From the distribution of antibodies between sites, it is clear that the RT1Aa molecule has three immunogenic areas against which nearly all the antibodies studied were directed. Of these areas one is both antigenically complex, consisting of four closely spaced sites, and remarkably immunodominant. Antibodies directed at sites between the major areas are extremely rare.