Physicochemical and biomechanical examination of surfaces of retrieved polyethylene heads from total hip prostheses with rotating polyethylene head system.

In order to assess whether hydrodynamic lubrication occurs in total hip prostheses with a rotating polyethylene (PE) head system (R-THP), several physicochemical, morphological, and biomechanical tests were carried out. R-THPs have been used in more than 1000 patients since 1970, and 12 PE heads, retrieved from 10 patients after an average of 24.5 years since total hip arthroplasty (THA), were employed for the tests. The weight-bearing area of the PE surface was light yellow in color and considerably oxidized, but no wear scars were observed. In the non-weight-bearing area, in contrast, discoloration and oxidation were hard to detect. The weight-bearing surface of the PE head became smoother with time after THA, and the friction coefficient did not differ significantly from that of an unused PE head. The radial clearance between head and socket decreased at a temperature of 17 degrees C, which is equivalent to the difference between room temperature and the temperature of the human body. Scanning electron microscopy showed a fine undulating pattern, which suggested that hydrodynamic lubrication could occur in the rotating PE head system.

Inotropic effects of histamine on developing chick heart: release of transmitters from autonomic nerve terminals.

Inotropic effects of histamine were examined in isolated ventricular preparations from late embryonic and hatched chick hearts. In 19 day-old embryonic preparations, histamine had little effect on the contractile force. In preparations from 1 to 2 day-old hatched chick, histamine produced a transient decrease in contractile force followed by a sustained increase. The negative and positive responses were antagonized by atropine and propranolol, respectively, but not by histamine antagonists terfenadine, cimetidine or thioperamide. Acetylcholine produced positive inotropic responses in the embryo while negative responses were observed after hatching. In myocardium of hatched chicks, compound 48/80, which releases histamine from mast cells, produced a transient decrease in contractile force followed by a sustained increase with a similar magnitude and time course to the case of exogenously applied histamine. The negative and positive responses were inhibited by atropine and propranolol, respectively, but not by terfenadine, cimetidine or thioperamide, which was similar to the case with the responses to histamine. The present results suggest that histamine, either applied exogenously or released from myocardial store sites, produces negative and positive inotropic responses in hatched chick myocardium which are due to release of acetylcholine and norepinephrine, respectively, from autonomic nerve terminals.

[Production of a monoclonal antibody against Cry j 2].

The peptide possessing N-terminal 10 amino acid sequence of Cry j 2 was chemically synthesized and conjugated to KLH-carrier protein. Rabbits were immunized with this haptenized protein and the antibody (N-10 antibody) was obtained. Cross-blot analysis revealed that N-10 antibody recognized the hapten moiety. Purification of Cry j 2 was carried out with monitoring its reactivity with N-10 antibody. The substance reactive to N-10 antibody existed in the DEAE-Sephadex unadsorbed fraction. The substance reactive to N-10 antibody was subjected to CM-Sephadex equilibrated with 10 mM acetate buffer (pH 5.0). In contrast to the previous report on Cry j 2, the substance reactive to N-10 antibody existed in the CM-Sephadex unadsorbed fraction. The CM-Sephadex unadsorbed fraction was concentrated with 80% saturated ammonium sulfate, and applied to a Superdex pg 200 column. The major peak of protein was regarded as the final preparation and was subjected to SDS-PAGE. The substance reactive to N-10 antibody had a MW of 40 kDa under reducing and 37 kDa under non-reducing conditions, respectively. Furthermore, the substance reactive to N-10 antibody showed potent allergenic activity. These data completely agreed with the previous data on Cry j 2 and strongly suggested that the final preparation contained a large amount of Cry j 2. BALB/c mice were immunized intraperitoneally with the final preparation to produce a monoclonal antibody against Cry j 2. Eleven clones reacting to the final preparation were obtained, and the antibodies produced from these clones did not react with purified Cry j 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronotropic and inotropic effects of histamine in developing chick heart: differential mechanisms before and after hatching.

Chronotropic and inotropic effects of histamine were examined in isolated atrial and ventricular preparations from embryonic and hatched chicken hearts. Histamine produced positive chronotropic and inotropic responses both in embryonic and hatched hearts. The responses to histamine in middle embryonic myocardia, which were observed in the micromolar range, were antagonized by H2 antagonists but not by H1, H3 antagonists and propranolol. Isobutyl-methylxantine, an inhibitor of phosphodiesterase, produced a leftward shift of the concentration-response curve for the chronotropic effect of histamine in the embryo. The responses to histamine in myocardia from hatched chicks, which were observed in the milimolar range, appeared concurrently with the responses to tyramine during development and were antagonized by beta adrenoceptor antagonists but not by any of the histamine antagonists. The positive inotropic response to histamine in hatched ventricular preparations were greatly attenuated by reserpine pretreatment or in the presence of desipramine. Thus, we demonstrated that exogenously applied histamine produces positive chronotropic and inotropic responses in developing chicken hearts and that the mechanisms are different between embryonic and hatched chicks: direct action on H2 receptors in the embryonic heart and release of norepinephrine from sympathetic nerve terminals in hatched hearts.

Antigenic relationship between the house dust mite Dermatophagoides farinae and the predacious mite Phytoseiulus persimilis.

We have examined the antigenic relationship between the house dust mite Dermatophagoides farinae and the predacious mite Phytoseiulus persimilis. Immunoblotting analysis demonstrated that there was a very weak antigenic cross-reactivity between these different suborder of mites but that this cross-reactivity was not attributed to D. farinaes major allergen's, Der fI and Der fII. These results suggest that P. persimilis might scarcely provoke allergic symptoms in patients sensitized to house dust mites.