Comparison of high purity factor IX concentrates and a prothrombin complex concentrate in a canine model of thrombogenicity.

A non-stasis canine model of thrombogenicity has been used to evaluate batches of high purity factor IX concentrates from 4 manufacturers and a conventional prothrombin complex concentrate (PCC). Platelets, activated partial thromboplastin time (APTT), fibrinogen, fibrin(ogen) degradation products and fibrinopeptide A (FPA) were monitored before and after infusion of concentrate. Changes in FPA were found to be the most sensitive and reproducible indicator of thrombogenicity after infusion of batches of the PCC at doses of between 60 and 180 IU/kg, with a dose related delayed increase in FPA occurring. Total FPA generated after 100-120 IU/kg of 3 batches of PCC over the 3 h time course was 9-12 times that generated after albumin infusion. In contrast the amounts of FPA generated after 200 IU/kg of the 4 high purity factor IX products were in all cases similar to albumin infusion. It was noted that some batches of high purity concentrates had short NAPTTs indicating that current in vitro tests for potential thrombogenicity may be misleading in predicting the effects of these concentrates in vivo.     

Artificial factor VIII deficient plasma: preparation using monoclonal antibodies and its use in one stage coagulation assays.

Monoclonal antibodies to factor VIII antigen (VIII:Ag) and von Willebrand factor (vWf:Ag) were immobilised on Sephacryl S-1000 and tested for their ability to deplete normal human citrated plasma of factor VIII. A combination of two antibodies to VIII:Ag and one antibody to vWf:Ag was required to produce plasma containing less than 0.01 IU/ml. Its performance in the one stage coagulation assay of VIII:C was equivalent to that of congenital VIII deficient plasma for the assay of normal and haemophilic plasma and factor VIII concentrates. Storage of freeze dried aliquots of this product at -20 degrees C, +4 degrees C, and 37 degrees C showed that it could be used as a substrate for at least six months when stored at temperatures +4 degrees C and below.     

Circulating lymphocyte populations and autoantibodies in non-obese diabetic (NOD) mice: a longitudinal study.

Several previous observations indicate a role for the immune system in the pathogenesis of insulin-dependent diabetes mellitus (IDDM) in non-obese diabetic (NOD) mice. In order to assess the status of the immune system in this model of spontaneous diabetes we studied the phenotype of circulating lymphocytes and the humoral autoimmunity to islet cells in non-diabetic NOD mice at various ages. Lymphocyte numbers were low in young NOD mice (age less than 160 days) as compared with other strains of mice and increased later to reach values in or above the range of controls. The percentages of circulating T lymphocytes and their L3T4+ and Lyt2+ subsets were higher in NOD mice of all ages and both sexes than in controls; however, no imbalance of the L3T4+ and Lyt2+ subpopulations was found. Anti-insulin autoantibodies were detected by an ELISA assay in all the NOD mice studied throughout the entire period of observation. Autoantibodies reacting with the cytoplasm of islet cells in Bouin's fixed pancreas sections, likely to be anti-insulin antibodies, were found in 47 to 58% of the samples from NOD mice aged 75 to 150 days. Antibodies to surface antigens of rat insulinoma cells were virtually absent in young NOD mice (75-100 days) and appeared in 33 to 43% of the samples from 150 to 185 days old NOD mice. The autoantibodies and the quantitative lymphocyte abnormalities reported here, although not predictive of the appearance of overt diabetes, are likely to be involved in the pathogenesis of the disease and therefore may indicate directions for future investigations.     

Comparative effects ofβ 2-adrenoceptor agonists on intracranial self-stimulation,Sidman avoidance,and motor activity in rats

The effects of -adrenoceptor agonists were compared in various operant behavioral tasks, particularly intracranial self-stimulation (ICSS). Clenbuterol, salbutamol, and terbutaline all reduced responding by rats that lever-pressed for low stimulation intensities. The effects of clenbuterol in this test were completely reversed by propranolol, and those of salbutamol were partly reversed. Intermediate doses of clenbuterol and salbutamol slowed the initiation of rewarding brain stimulation in a shuttlebox but had little or no effect on the termination latencies. However, higher doses of both drugs lengthened the termination latencies. Motor activity was reduced at doses that attenuated ICSS responding. Complete tolerance occurred within 4 days to the effects of clenbuterol and salbutamol on leverpressing ICSS and to the effects of clenbuterol on motor activity. The apparent performance deficits induced by these drugs were overcome by more intense motivation. For example, even at high doses, clenbuterol reduced ICSS leverpressing only partially when animals bar-pressed for high rather than low stimulation intensities. Furthermore, all three drugs failed to alter Sidman avoidance responding at doses up to 100 times those that attenuated ICSS responding. It is concluded that although -adrenoceptor agonists cause apparent sedation in rats, this sedation is limited and shows rapid tolerance.     

Superoxide dismutases in Eimeria tenella.

Unsporulated oocysts of Eimeria tenella have high superoxide dismutase (SOD: superoxide:superoxide oxidoreductase, EC 1.15.1.1.) activity and contain several electrophoretically distinct forms of the enzyme, including two forms of Cu/Zn-containing SOD, two forms of Fe-SOD and two forms of Mn-SOD. SOD activity remains high during 12 h of sporulation but diminishes slowly during prolonged sporulation. Oocysts sporulated for 48 h have low levels of superoxide dismutase and contain only one form of the enzyme (Mn-SOD), which was also found in sporozoites. In vitro, sporozoites are oxidant-sensitive and die within minutes of superoxide radical (O2-) generation but SOD/catalase and mannitol protect sporozoites against oxidative damage. These data suggest that E. tenella sporulated oocysts and sporozoites lack soluble cytoplasmic SOD and that this deficiency may contribute to the oxidant sensitivity of the parasite.     

Effects of various catecholamine receptor antagonists, muscle relaxation and physical hindrance on shuttlebox self-stimulation

Certain drugs, particularly clozapine and clonidine, have been reported to increase selectively the latency to initiate brain stimulation (the ON latency) in a shuttlebox test of self-stimulation, suggesting a preferential attenuation of the "reward" component. The pharmacological selectivity of this reported effect was systematically evaluated. At doses that blocked bar-pressing self-stimulation, metoclopramide (3 mg/kg), prazosin (3 mg/kg) clonidine (0.1mg/kg), clozapine (3 mg/kg)and haloperidol (0.3 mg/kg), all elevated the ON latency to a greater extent than the OFF latency. Methocarbamol (200 mg/kg), and a muscle relaxant, also elevated the ON latency preferentially but the magnitude of this preferential effect was smaller than that produced by the other drugs. A hurdle in the center of the shuttlebox increased the ON and OFF latencies nonselectively. The shuttlebox procedure does not clearly discriminate among various substances that interfere with noradrenergic or dopaminergic neurotransmission, but the common profile produced by the these substances is distinguishable to some degree from simple motor disruption.     

Chemical resistance of the gram-negative bacteria to different sanitizers in a water purification system

Background  

Purified water for pharmaceutical purposes must be free of microbial contamination and pyrogens. Even with the additional sanitary and disinfecting treatments applied to the system (sequential operational stages), Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas alcaligenes, Pseudomonas picketti, Flavobacterium aureum, Acinetobacter lowffi and Pseudomonas diminuta were isolated and identified from a thirteen-stage purification system. To evaluate the efficacy of the chemical agents used in the disinfecting process along with those used to adjust chemical characteristics of the system, over the identified bacteria, the kinetic parameter of killing time (D-value) necessary to inactivate 90% of the initial bioburden (decimal reduction time) was experimentally determined.