Protective reactions of gastropod molluscs. 1. Cell reactions

Protective reactions of molluscs are traditionally considered in cell and humoral aspects. The paper analyses original data and recent reference data oncell (phagocytic) reactions of gastropod molluscs. The main attention is paid to peculiarities of hemopoiesis, cell elements of hemolymph, and dynamics and mechanics of encapsulating the parasites.     

Defensive reactions of gastropod molluscs. Humoral reactions

Humoral protective reactions and their mechanisms in gastropod mollusks are considered based on the results of various investigations. It is important to note that lectines in molluscs, as well as in other invertebrates, are functional analogues of immunoglobulins in vertebrates.     

Anti-IgA-mediated transfusion reactions in Canada.

During a 6-year period (1977 to 1982) blood samples from 152 Canadian patients were referred to the national reference laboratory of the Canadian Red Cross Society because the referring hospitals had not been able to determine the cause of the patients'' severe nonhemolytic transfusion reactions. Twenty-one patients were found to be IgA deficient, and 12 of them had strong class-specific anti-IgA antibodies, which were presumed to have been responsible for the reactions. The spectrum of symptoms that accompanied these violent reactions was documented for 10 of the patients. As a probable minimum, the incidence of anti-IgA-mediated reactions averaged 1.3 per million units of blood or blood products transfused during this period.     

Enzyme reactions in a membrane model. 1. A new technique to study enzyme reactions in monolayers

Enzymic hydrolysis by pancreatic phospholipase A (EC 3.1.1.4) of 3-sn-didodecanoyl phosphatidylglycerol was studied under constant surface pressure. A technical device is described which automatically keeps the surface pressure constant and which continuously registers the movement of the surface barrier. A new trough design is proposed which consists of two compartments connected by a narrow surface canal. With this trough the recorded kinetic plots are linear, in contrast to the non-linear kinetic plots obtained with the usual one-compartment trough.     

Phosphorylation reactions in islets of Langerhans.

The possible significance of phosphorylation reaction in islets of Langerhans in relation to the secretion of insulin is discussed. The secretagogues, glucose and its metabolites, cAMP and Ca++ and their influences on protein-kinase activity are given particular attention. The data obtained by the authors, as well as by other groups, are in agreement that cAMP is a potent stimulator of protein kinase activity. Glucose and its metabolites influenced protein kinase activity in one instance. Ca++ in supraphysiological amounts inhibited protein phosphorylation. The links between phosphorylation reactions and insulin secretion are, at the present time, conjectural.     

Evolutionary conservation of reactions in translation.

Current X-ray diffraction and cryoelectron microscopic data of ribosomes of eubacteria have shed considerable light on the molecular mechanisms of translation. Structural studies of the protein factors that activate ribosomes also point to many common features in the primary sequence and tertiary structure of these proteins. The reconstitution of the complex apparatus of translation has also revealed new information important to the mechanisms. Surprisingly, the latter approach has uncovered a number of proteins whose sequence and/or structure and function are conserved in all cells, indicating that the mechanisms are indeed conserved. The possible mechanisms of a new initiation factor and two elongation factors are discussed in this context.     

Anaphylactic reactions to cinoxacin.

During 1981 to mid-1988 three cases of anaphylactic shock after treatment with the quinolone derivative cinoxacin were reviewed by the Netherlands Centre for Monitoring of Adverse Reactions to Drugs and 17 cases of an anaphylactic type of reaction notified to the World Health Organisation Collaborating Centre for International Drug Monitoring. In five out of six patients for whom data were available the reaction began shortly after taking a single capsule of a second or next course of treatment. Cinoxacin is related to nalidixic acid, and one patient previously treated with that agent subsequently had an anaphylactoid reaction to cinoxacin and later developed a skin reaction to nalidixic acid. There were no deaths, and patients treated as an emergency with plasma expanders or with adrenaline and corticosteroids generally recovered promptly and uneventfully. In view of the potentially fatal consequences of anaphylactic reactions to cinoxacin and other quinolones doctors should take care when prescribing these drugs.     

Identification of adverse reactions to new drugs. IV--Verification of suspected adverse reactions.

The verification processes were assessed for 18 important adverse drug reactions. Verification when achieved by formal studies was not obtained through cohort studies such as postmarketing surveillance or other follow up of drug users but through case-control studies or a similar disease orientated approach. When not achieved in this way the most useful aspects of uncontrolled studies were rechallenge and dose-response data. Analysis of the data and of the characteristics of different methods of verification suggested that there were four approaches to earlier discovery. (1) The best system seemed to be some form of record linkage, capable of providing at the same time data on incidence of adverse reactions and on prevalence of drug usage in patients with disease suspected of being drug induced. Until such a system can be established the relative efficacy of alternative approaches appears to be (2) review of all published first alerts, with prompt initiation of case-control or disease orientated studies for verification, (3) postmarketing surveillance of cohorts of drug users, and (4) voluntary reporting systems.     

Immune reactions in polysaccharide media. Polysaccharide-enhanced precipitin reactions with antigens of various sizes

The influence of the size of the antigen in the polysaccharide-enhanced precipitin reaction was investigated. The experiments were carried out by addition of homologous antigens of different molecular sizes (the monomer, dimer and trimer of serum albumin and the monomer and dimer of immunoglobulin G) to the same preparation of antibody in the absence and presence of dextran. Dextran decreased the solubility of the immune complexes to a larger extent when the antigen size increased. This is in accord with the view that the polysaccharide effect is due to steric exclusion.