Immune and pathologic responses in mice infected with Brucella abortus 19, RB51, or 2308.

Immune and pathologic responses were measured for 20 weeks after infection of mice with Brucella abortus 19, RB51, or 2308. Live bacteria and bacterial antigens of 19 and RB51 persisted in spleens for 10 and 4 weeks after infection, respectively, whereas 2308 bacteria and bacterial antigens persisted for at least 20 weeks. Small germinal centers and profound lymphoid depletion occurred in spleens of mice during the first 4 weeks of infection with strain 19 or 2308; however, mice infected with strain RB51 had much larger germinal centers but no lymphoid depletion. At 4 weeks, only spleen cells from RB51-infected mice proliferated when incubated with 2308 bacteria. Large germinal centers in the spleen and spleen cell proliferative responses to 2308 did not appear in strain 19-infected mice until 6 weeks or in strain 2308-infected mice until 10 weeks. Similar proliferative responses to 2308 occurred in mice infected with strain 19 or RB51 at 6 weeks and in mice infected with strain 19, RB51, or 2308 at 10 weeks. However, at 20 weeks, spleen cell proliferative responses to 2308 occurred in mice infected with strain 19 or 2308 but not in mice infected with strain RB51. Mice infected with strain RB51 had lower and less persistent antibody titers to 2308 than did mice infected with strain 19 or 2308. Collectively, these results indicate that RB51-infected mice have less persistent immune responses to 2308 than do mice infected with 19 or 2308. The shorter duration of the responses probably resulted because RB51 is considerably less pathogenic and is cleared more rapidly from mice than are 19 and 2308.     

Lymphocyte proliferation in response to Brucella abortus RB51 and 2308 proteins in RB51-vaccinated or 2308-infected cattle.

Cattle vaccinated with Brucella abortus strain RB51 (SRB51) or infected with strain 2308 (S2308) had lymph node lymphocytes which proliferated most when incubated with 32-, 27-, 18-, or <18-kDa proteins of either SRB51 or S2308. Some S2308-infected cattle but no SRB51-vaccinated cattle had lymphocytes which proliferated in response to 80- and 49-kDa proteins of SRB51 and S2308. These results suggest that cattle vaccinated with SRB51 or infected with S2308 have lymphocytes which proliferate in response to most of the same S2308 proteins and that the immunodominant protein antigens of SRB51 and S2308 have similar molecular masses of 32, 27, 18, and <18 kDa.     

Purification and biochemical properties of a bacteriocin from Actinobacillus actinomycetemcomitans.

Extracts of certain strains of Actinobacillus actinomycetemcomitans are inhibitory to strains of Streptococcus sanguis such as S. sanguis ATCC 10556. The isolation of a protein from an A. actinomycetemcomitans sonic extract which copurified with the inhibitory activity was accomplished by preparative isoelectric focusing, Sephadex G-100 gel filtration chromatography, and preparative polyacrylamide gel electrophoresis (PAGE). The resulting isolated protein, which focused at a pH of 6.1 to 6.3, appeared as a single band in anionic nondissociating PAGE analysis. This protein could be dissociated into two subunits with molecular weights of 50,000 and 70,000, which were resolvable by PAGE analysis. A 1,758-fold increase in specific activity was seen in the purified inhibitory protein compared with the crude sonic extract starting material. The properties of the inhibitory activity in the A. actinomycetemcomitans extract are characteristic of a bacteriocin. Accordingly, we propose the name actinobacillicin for the inhibitory protein.     

Normal or early development of puberty despite gonadal damage in children treated for acute lymphoblastic leukemia

To determine the timing of pubertal development and the frequency of gonadal dysfunction in children who survive acute lymphoblastic leukemia, we assessed pubertal status and the plasma levels of sex steroids, gonadotropin, and inhibin in 45 children (20 girls and 25 boys) who had received combination chemotherapy along with 24 Gy of irradiation to the cranium (modified LSA2L2 protocol). We also reexamined testicular biopsy specimens, obtained at the time of the cessation of chemotherapy, for the presence of germ cells. Germ-cell damage, indicated by marked elevations in the plasma level of follicle-stimulating hormone (P less than 0.001 for the comparison with normal children), was evident in both sexes and was confirmed in the boys by the absence of germ cells in the testicular biopsy specimens and by the small size of the testes for pubic-hair stage. Only 44 percent of the pubertal girls had measurable plasma inhibin levels, as compared with more than 93 percent of normal pubertal girls. Although plasma sex-steroid levels were normal, the secretion of luteinizing hormone in response to stimulation with gonadotropin-releasing hormone was elevated in the pubertal children (P less than 0.01 for the comparison with normal controls)--a finding that suggests compensation for decreased gonadal function. Despite clear evidence of gonadal damage, girls had early menarche at a mean age (+/- SD) of 11.95 +/- 0.91 years, as compared with the Australian standard of 12.98 +/- 1.11 years (P less than 0.01). Thus, in girls, puberty was early despite primary gonadal damage. Thirteen of 23 boys reached puberty at a mean age of 12.36 +/- 0.73 years. We conclude that treatment for acute lymphoblastic leukemia may lead to primary gonadal damage in both sexes, regardless of the age at treatment, but that the secondary characteristics of puberty develop at a normal age or, in girls, relatively early.     

Activation of peritoneal macrophages by concanavalin A or Mycobacterium bovis BCG for fungicidal activity against Blastomyces dermatitidis and effect of specific antibody and complement.

With a new short-term assay, where the reduction of CFUs in the inoculum could be measured, we investigated the killing of the dimorphic fungal pathogen Blastomyces dermatitidis in its yeast phase by murine peritoneal macrophages. Peritoneal macrophages from concanavalin A- or Mycobacterium bovis BCG-treated mice, but not resident or thioglycolate-elicited macrophages, significantly reduced the CFUs of B. dermatitidis in the inoculum. The activation of peritoneal macrophages for fungicidal activity by concanavalin A treatment was shown to be dose dependent and transient, i.e., absent after 72 h. These results indicate that it is possible for murine peritoneal macrophages to kill B. dermatitidis in vitro. The addition of specific antibody or complement or both did not enhance the killing of B. dermatitidis by these nonspecifically activated macrophages.     

Epidemiological Investigation of Vaginal Saccharomyces cerevisiae Isolates by a Genotypic Method

Saccharomyces cerevisiae is a ubiquitous, ascomycetous yeast, and vaginitis caused by this organism has been reported only very rarely. The aim of the present investigation was to assess the epidemiological relatedness of a group of vaginal and commercial S. cerevisiae isolates by a previously reported genetic typing method, which divided the isolates into two broad groups with numerous subtypes. Nineteen S. cerevisiae isolates obtained from patients suffering from vaginitis and four isolates from commercial products in the same city were analyzed. The cellular DNA from each isolate was digested with the restriction endonuclease EcoRI, and restriction fragment length polymorphisms were generated by horizontal gel electrophoresis. The results showed that although vaginal isolates did not cluster in any particular genetic subtype, multiple patients were infected with indistinguishable strains (there were nine distinct strains among 23 isolates). For two of three patients, all three with two episodes of S. cerevisiae vaginitis, different strains were isolated during the recurrence of this disease. Three other patients with indistinguishable isolates were epidemiologically related in that two were practitioners in the same clinic and the third was a patient at this clinic. We also found that one commercial strain was indistinguishable from the strain isolated from three different women at the time that they were suffering from vaginitis. The findings of the present study suggest that some S. cerevisiae strains may possess properties permitting persistence in the human host. Furthermore, person-to-person contact and the proliferation of the use of S. cerevisiae as a health-food product, in home baking, and in home brewing may be a contributing factor in human colonization and infection with this organism.     

Basic isoferritin and hypercalcaemia in renal cell carcinoma

A 63-year-old man with iron loss anaemia and hypercalcaemia was found to have a renal cell carcinoma. Despite the iron-deficient blood and bone marrow picture, the serum ferritin concentration was markedly raised. This was mainly due to a “basic isoferritin”. The serum parathormone concentration was normal. The serum ferritin and calcium concentrations returned to normal after the tumour was removed. We propose that the renal cell carcinoma cells in this patient secreted the basic isoferritin as well as humoral factor(s) responsible for hypercalcaemia.     

Sialidases (neuraminidases) in bacterial vaginosis and bacterial vaginosis-associated microflora.

Bacterial vaginosis, Prevotella species, and Bacteroides species have been associated with prematurity and upper genital tract infection. Prevotella (Bacteroides) species and Bacteroides fragilis have also been associated with preterm birth. However, the mechanism by which lower genital tract infection causes upper genital tract disease remains poorly understood. Sialidases (neuraminidases) are enzymes which enhance the ability of microorganisms to invade and destroy tissue. Elevated levels of sialidase activity were detected in 42 (84%) of 50 vaginal fluid specimens from women with bacterial vaginosis and none of 19 vaginal fluids from women without bacterial vaginosis (P less than 0.001). Vaginal fluid from women with bacterial vaginosis had a median specific activity of 9.8 U compared to 2.5 U of sialidase in women without bacterial vaginosis (P less than 0.001). In order to determine the probable source of sialidases in vaginal fluid, the microorganisms recovered from women with bacterial vaginosis before and after treatment were assayed. Of 28 specimens from women with bacterial vaginosis, 27 (96%) yielded sialidase-positive bacteria, at a median concentration of 10(6.5) CFU/ml of vaginal fluid. Prevotella and Bacteroides species accounted for the sialidase activity in 26 of the vaginal fluids, and Gardnerella vaginalis accounted for the sialidase activity in the remaining fluid. After treatment, sialidase was detected in the vaginal fluid of 1 (5%) of 22 women who responded to therapy and in all of 6 women for whom therapy failed. These data suggest that vaginal fluid sialidase is highly correlated with bacterial vaginosis and that the probable sources for this enzyme activity are the Bacteroides and Prevotella species present in the vagina.     

Comparative analysis of genetic variability among Candida albicans isolates from different geographic locales by three genotypic methods.

The objective of the present study was to conduct a comparative genotypic analysis of Candida albicans isolates from the United States, Europe, and Southeast Asia to determine whether differences between isolates might be associated with geographic locations. The genotypes of 86 unrelated isolates of C. albicans (from the United States and Europe) and 26 isolates from Singapore were examined by three DNA typing methods. Computer-assisted methods were used to analyze the gel patterns for all isolates. A dendrogram based on the overall similarity of the patterns obtained by restriction endonuclease analysis (REA) with EcoRI clustered the U.S. and European isolates into two major groups (groups A and B). The Singaporean isolates demonstrated unique REA profiles, with nine isolates having both or neither of the REA-characteristic 3.7- and 4.2-kb bands present in groups A and B. By REA profiles, the Singaporean isolates were related to each other with similarity values (S(AB)s) of > 0.80, but only one isolate mixed with the U.S. and European isolates at this S(AB) (an arbitrary threshold for genetic similarity). Randomly amplified polymorphic DNA (RAPD) analysis generated DNA profiles that clustered the C. albicans isolates into approximately the same number of distinct typing groups as REA. However, isolates identical to each other by REA were generally different from each other by RAPD analysis. In a composite dendrogram prepared from the results obtained by RAPD analysis, the isolates from the United States and Europe clustered in major groups with S(AB)s of > 0.85, while Singaporean isolates connected to these clusters at S(AB)s of > or = 0.75. Pulsed-field gel electrophoresis was less discriminatory, discerning about one-third as many distinct subtypes as REA or RAPD analysis; the Singaporean isolates were distributed randomly with the U.S. and European isolates. These results suggest that a high degree of genetic diversity exists between C. albicans isolates from Southeast Asia and those from the United States and Europe.