Microcapsule of Campylobacter fetus: chemical and physical characterization.

The antiphagocytic antigen (antigen [a]) comprising the microcapsule of a strain of Campylobacter fetus subsp. intestinalis has been purified from culture supernatants by ammonium sulfate fractionation and free-flow electrophoresis. Antigen [a] is a glycoprotein containing about 4% carbohydrate consisting of hexose, pentose, and methylpentose. The composition of the protein was typical of bacterial extramural structural proteins in its low content of basic, aromatic, and sulfur-containing amino acids. The protein had a high content of aspartic acid, threonine, glycine, and alanine. Antigen [a] had an Rf of 0.33 on polyacrylamide gel electrophoresis and a molecular weight calculated in sodium dodecyl sulfate-polyacrylamide gel electrophoresis of approximately 98,000. In contrast to its free form in culture supernatants, antigen [a] in vesicles derived from sheared cells appeared to exist in a complex with lipopolysaccharide. This complex could be dissociated by ethylenediaminetetraacetic acid or by ethylenediaminetetraacetic acid plus Triton X-100. A mutant strain that lacked a microcapsule, when incubated with soluble antigen [a] in a calcium medium, became agglutinable by monospecific [a] antiserum and showed an additional structural layer similar in appearance to the microcapsule on its cell wall. Points of similarity are emphasized between antigen [a] of C. fetus and the outer structural protein of the taxonomically related Spirillum serpens.

[The noninvasive determination of cardiac output by means of impedance cardiography. Comparative evaluation with a thermal dilution technique (author's transl)]. / Die unblutige Bestimmung des Herzzeitvolumens mit der Impedanzkardiographie. Vergleichende Untersuchungen mit der Thermodilutionsmethode

When a high frequency alternating current is passed through the thorax by means of tape-electrodes, the electrical impedance Z is changing synchronously with the cardiac cycle. The relation between the first derivative dZ/dt and the stroke volume is the basis for the application of impedance cardiography (IK) Determinations of cardiac output (CO) at rest during ergometer exercise using this noninvasive technique were compared with CO values obtained by the thermal dilution method. In 57 subjects simultaneous determinations using both methods were performed at resting conditions. The correlation coefficient was r = 0.63. In addition, in 48 of the subjects CO was measured with both methods during supine ergometer exercise. Comparison of the exercise values resulted in a correlation coefficient of r = 0.63. In all 48 cases there was a concordant change of the IK and thermodilution CO values. It is concluded that relative changes of CO are reliably detected by IK. The absolute values can be utilized only approximately.

[Determination of cardiac output by means of an automatized thermal dilution technique (author's transl)]. / Die Bestimmung des Herzzeitvolumens mit einer automatisierten Thermodiluntionsmethod

Cardiac output was measured in 55 patients by the direct Fick method and an automatized thermodilution method. The results showed a good correlation (correlation factor r = 0.87, regression equation y = 0.91 x + 0.59). For the thermodilution method ice-cold normal saline solution as indicator substance was injected into the right atrium. The temperature-time-curve was measured by a thermistor located in the pulmonary artery. The area of indicator dilution was determined by electronic integration, the calculated cardiac output appeared as 1/min in digital display.

Bovine veneral vibriosis: antigenic variation of the bacterium during infection.

Host parasite relationships in the female genital tract were studied in bovine venereal vibriosis by investigating agglutinin production and alterations in superficial antigens of the bacterium during the course of infection in two heifers. Cervicovaginal mucus (CVM) steamed cell agglutinins were shown to appear earlier and remain at consistently higher levels than whole-cell agglutinins. Whole-cell agglutinin titers fluctuated much more than steamed cell titers, suggesting possible changes in whole-cell antigens. Marked antigenic variation was demonstrated in successive monthly CVM isolates from the two heifers by agglutination tests with rabbit antisera of various specificities. Some changes in CVM antibody specificity during the infection were noted also. Antigenic variation in the bacterium was proposed as a mechanism for maintenance of the asymptomatic cervicovaginal carrier state in the presence of antibody.