Biomedical subjects
Publications and source records attributed to J S Lin.
An unstable nitroxide identified by electron paramagnetic resonance spectra was obtained by oxidation of N-methyl-gamma-tocopheramine with peroxide and also by ultraviolet photooxidation.
Serotyping of strains of Mycoplasma hominis, freshly isolated from various sources, was conducted using the complement-independent growth agglutination (GA) test, using the 7 reference antisera prepared in our laboratory. Multiple isolates from a common source indicated that only a single serotype tends to be found, making it possible to serotype clinical isolates without further cloning. However, cultures collected at different times from the same individual may contain different serotypes. A total of 213 recent cultures were serotyping and a majority of these were assigned to the closely related serogroups 1, 2, and 3. Strains isolated during pregnancy, that were associated with various disorders of pregnancy, were serotypically diverse and no one strain seemed to be particularly likely to be associated with disorders of pregnancy.
We studied 204 women with acute pelvic inflammatory disease to delineate further the causes of that illness. Gonococci were recovered from 91. Gonococcal pili antibody rose or fell significantly in 12 of 18 patients with positive cultures and only two of 19 who had negative cultures and smears for Neisseria gonorrhaoea(P smaller than 0.005). N. gonorrhoeae was found in peritoneal exudate from eight of 21 patients with, and none of 33 without, cervical gonococcal infection. Among patients with severe disease, other bacteria were recovered from peritoneal exudates from five of 16 with, and 19 of 22 without, cervical gonococcal infection (P smaller than 0.025). Mixed anaerobic and aerobic bacterial peritoneal infection was common in nongonococcal pelvic disease. The most common species recovered were Bacteroides fragilis, peptostreptococci, and peptococci. Tuboperitoneal gonococcal infection probably causes pelvic inflammatory disease in most patients with cervical gonococcal infection, whereas polymicrobial tuboperitoneal infection probably causes most nongonococcal cases.
Blood obtained from three hundred and twenty-seven women within a few minutes of vaginal delivery was cultured for genital mycoplasmas (Mycoplasma hominis and T mycoplasmas). Twenty-six (8%) of the women had genital mycoplasmas isolated from their blood. Ten women had blood-cultures which contained M. hominis. Fifteen women had blood-cultures which contained T mycoplasmas. Both M. hominis and T mycoplasmas were isolated from the blood of one woman. Only one of two hundred and seventy-three blood-cultures obtained 1 or more days after delivery contained mycoplasmas. The isolation of M. hominis, but not of T mycoplasmas, from the blood was associated with vaginal colonisation and a serological response to the homologous isolate. Two of ten women whose blood contained M. hominis gave birth to stillborn infants. In contrast, there were only four (1.3%) stillbirths among the infants born to the three hundred and one women whose blood did not contain mycoplasmas. This difference is statistically significant.
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In the usual serologic test for Mycoplasma hominis, disks containing antibody to a prototype strain are applied to an agar plate that has been inoculated with the microorganism to be tested, and inhibition of growth is studied. The recent demonstration that M. hominis is not serologically homogeneous but consists of at least seven serotypes suggested the need for reexamination of the specificity of the disk test. The inhibition of growth of M. hominis on solid medium by disks containing seven antisera to the seven prototype strains was studied. Antisera to strains 1, 2, and 3 significantly inhibited all seven prototype strains, but the other four antisera did not inhibit the growth of all heterologous strains. The individual antisera 1, 2, and 3 did not inhibit all of a group of 19 recent genital isolates of M. hominis. However, when the three antisera were combined, they inhibited all 19 isolates as much as or more than any of the three alone. The growth of the prototype strain 5 (PG 21) and of some recent clinical isolates was not completely prevented by the homologous or reference antisera, but the growth of all was partially inhibited.
Several in vitro reactions between a strain of M. hominis (no. 4195) and homologous antiserum have been delineated and compared. One complement-dependent and four complement-independent activities of antibody have been studied. The complement-dependent activity was mycoplasmacidal and was inhibited by the presence of arginine in the test medium. The complement-independent antibody-mediated reactions were not mycoplasmacidal and were four in number: (a) agglutination, which was manifested in buffered saline after incubation for 24-48 h at 36 degrees C, and in which the end-points were dependent upon the concentration of antigen; (b) metabolic inhibition, in which antiserum added to liquid growth medium produced slowing of the rate at which the pH rises during growth; (c) agglutination during growth, which occurred in liquid growth medium after the addition of antiserum and coincided with, but generally preceded, metabolic inhibition; and (d) inhibition of multiplication in which high concentrations of antiserum led to inhibition of multiplication or metabolic activity, with persistence of viable mycoplasmas, under otherwise favourable conditions of growth. The end-points for each of the above methods of detecting antibody are not identical.
Serological studies on the genital mycoplasmas (U. urealyticum and M. hominis) are briefly reviewed. Newly developed serological tests from our laboratory have been applied to the studies of mycoplasma strains and antibody responses in patients. The data indicate that genital mycoplasmas are serologically diverse, with at least 11 serotypes of U. urealyticum and 7 of M. hominis. No one serotype predominates in relation to any known association with illness. However, serological and cultural data indicate a strong link between genital mycoplasmas and perinatal morbidity and mortality.
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Seven strains of Mycoplasma hominis from human genital tracts were selected to produce antisera. The complement-dependent mycoplasmacidal (MC) activity and two complement-independent activities, metabolic inhibition (MI) and agglutination during growth (GA), of these sera were compared. The GA and MI tests were equivalent in titer and generally not affected by concentration of antigen; they revealed specific cross-reacting patterns among the seven strains. There was little if any cross-reactivity with antisera to other human mycoplasmas or to Mycoplasma arthritidis. Control sera from unimmunized rabbits and sera against concentrated uninoculated culture media were also nonreactive. On the other hand, the sensitivity and specificity of the MC test were affected by the concentration of antigen: at about 10(2) color-changing units (CCU) of antigen, all strains were equivalently cross-reactive against the seven antisera, but at 10(2) to 10(4) CCU the individual strain specificity appeared, whereas at about 10(5) CCU little or no antibody was detectable by MC. The MC tests with the lowest concentrations of antigen gave the highest titers of antibody, but at such low concentrations of antigen there was not only loss of individual strain specificity but also some cross-reactivity against other human mycoplasmas, M. arthritidis, or control rabbit sera. Studies with paired human sera also indicate that the MC test with small amounts of antigen is more sensitive than GA-MI.
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