Some properties of solutions of a functional-differential equation of second order with delay.

Existence, uniqueness, data dependence (monotony, continuity, and differentiability with respect to parameter), and Ulam-Hyers stability results for the solutions of a system of functional-differential equations with delays are proved. The techniques used are Perov's fixed point theorem and weakly Picard operator theory.

Detoxified hymenoptera venoms: preliminary studies of in vitro cytotoxicity and antigenicity of Apis mellifera 'venomoid'.

The preparation of detoxified venom (venomoid) of Apis mellifera is described. The venomoid obtained by formaldehyde detoxification retained significant antigenicity. Radioallergosorbent test (RAST) inhibition studies indicated a loss of the affinity of the venomoid for the venom-specific human IgE antibody.

Optimal antibody-receptor ratio in anaphylactic-sensitization.

The antigen-induced release of histamine from guinea pig and monkey lung fragments sensitized in vitro with hyperimmune rabbit antibody and human reaginic serum, respectively, was studied. When the amounts of whole antiserum, gamma-globulin fraction, or purified antibody were increased over the optimum in passive anaphylactic sensitization, the subsequent histamine release was reduced in spite of the fact that proportionately greater amounts of antigen were added to the system. The observed inhibition by higher antibody concentrations might be due to a reduction in cell-stimulating capacity of the antigen-antibody-receptor complex caused by inappropriate ratios among any of these three components.

Studies of the antigenicity and allergenicity of phospholipase A2 of bee venom.

The antigenic and allergenic properties of phospholipase A2 (PLA2) and whole bee venom were compared by measuring the IgG and IgE antibody responses in animals and man. Precipitating antibodies raised in rabbits and reaginic and other antibodies raised in mice reacted about equally with both bee venom and PLA. The majority of human sera containing bee venom-specific IgE also contained PLA-specific IgE, although in somewhat lower titers.

Inhibition of antigen-induced histamine release by ouabain.

The effect of ouabain, a specific sodium-potassium dependent adenosine triphosphatase (Na+-K+-ATPase) inhibitor, on antigen-induced histamine release was studied using guinea pig lung fragments sensitized in vitro with rabbit antibodies against bovine serum albumin. Histamine was assayed spectrofluorometrically. When sensitized tissue had been preincubated with ouabain (less than or equal to 1.

Long-term study of the risk factors in atherosclerosis.

A study of the risk factors in atherosclerosis carried out in 595 subjects over a period of 10 years showed an increased prevalence of arterial hypertension, of high serum cholesterol values and of overweight in 1970 as compared to 1960. This rise was significant for all the parameters studied and was particularly evident in serum cholesterol values and overweight, beginning with the 21 to 30 age decade. The frequency of subjects with risk factors increased with age.

The effect of Tris-buffered media and Tyrode physiologic saline solution on the antigenic release of histamine from human leukocytes.

Allergic histamine release from leukocytes was compared in three different media: Tyrode physiologic saline solution, Tris-buffered saline containing human albumin, calcium, and magnesium (Tris-ACM), and Tris-ACM with homologous serum. In a selected group of low histamine releasers, the maximal amount of antigenic histamine release was significantly higher in Tyrode solution as compared to Tris-ACM buffer. When homologous serum was added to Tris-acm, an enhancement of histamine release greater than with Tyrode solution was obtained.