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Biomedical subjects

C R Gregg

Publications and source records attributed to C R Gregg.

23 records · Page 2Linked to original sources
PubMed1981

Toxic activity of purified lipopolysaccharide of Neisseria gonorrhoeae for human fallopian tube mucosa.

An experimental model of human fallopian tubes in organ culture was used to examine the ability of lipopolysaccharide (LPS) of Neisseria gonorrhoeae to damage the fallopian tube mucosa. Gonococcal LPS was purified by hot phenol-water extraction and sequential ultracentrifugation. This LPS was highly lethal for lead-sensitized mice and at a concentration as low as 6 pg/ml reproducibly gelled limulus amoebocyte lysate. Gonococcal LPS damaged fallopian tube mucosa in concentrations as low as 0.015 microgram/ml, a values less than the LPS concentration in organ culture medium surrounding fallopian tube mucosa that was damaged by gonococcal infection. The toxic effect of LPS was neutralized by polymyxin B. Gonococci were shown to elaborate blebs of outer membrane material that is likely to contain LPS. These studies suggest that gonococci elaborate LPS-containing material into their surrounding medium, that the LPS is capable of mediating damage to human fallopian tube mucosa, and that the production of mucosal damage requires the lipid A portion of the LPS molecule.

Animals↗
PubMed1980

Gonococcal lipopolysaccharide: a toxin for human fallopian tube mucosa.

Gonococci damaged the mucosa of human fallopian tubes in organ culture (FTOC), producing characteristic pathologic features. Filter-sterilized supernatant fluid from donor gonococcal-infected FTOC damaged recipient FTOC in a similar fashion. Gonococcal lipopolysaccharide (LPS) was detected in these toxic donor fluids in concentrations of 1.2 to 8.3 microgram/ml. Purified gonococcal LPS in concentrations as low as 0.015 microgram/ml produced damage equivalent to that caused by toxic donor fluid and was neutralized by polymyxin B. Such LPS-mediated damage to ciliated cells, if it occurs in gonococcal salpingitis, may impair mucociliary flow and predispose to ectopic pregnancy and recurrent ascending infection.

Animals↗
PubMedDate not supplied

Spontaneous and interferon resistant natural killer cell anergy in AIDS.

The acquired immunodeficiency syndrome (AIDS) is characterized by severe unrelenting opportunistic infections and/or Kaposi's sarcoma associated with a dysfunction of cell mediated immune responses. In addition to cutaneous anergy and inversion of T-helper/inducer to T-suppressor cell ratios usually observed in AIDS, we have observed in three AIDS cases with multiple opportunistic infections that spontaneous and interferon (IFN) stimulated natural killer (NK) cell activity against K-562 cells is absent or severely depressed as compared to controls. Spontaneous and IFN stimulated NK cell activity in promiscuous male homosexual controls was similar to that observed in heterosexual controls. The control subjects had T-helper:T-suppressor ratios ranging from 1.1 to 2.4 in contrast to the AIDS subjects who had typical inverted ratios of T-cells ranging from 0.17 to 0.54. HNK-1, a monoclonal antibody that identifies NK and antibody-dependent cytotoxic cells, marked 3-22% of peripheral blood lymphocytes from AIDS patients in comparison to 8-38% of lymphocytes from controls. A larger series will be required in order to ascertain the true incidence of NK cell anergy in AIDS and whether or not subgroups exist based on the association of Kaposi's sarcoma in the disease process.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Infections caused by Mycobacterium szulgai in humans.

Mycobacterium szulgai is a scotochromogenic species that has recently been recognized as a human pathogen. Twenty-four cases of disease caused by M. szulgai in humans have been reported in the English-language literature. The clinical features of these cases were reviewed, and three additional cases (two pulmonary, one extrapulmonary) were studied. Pulmonary disease indistinguishable from that caused by Mycobacterium tuberculosis was the commonest type of infection caused by M. szulgai (18 of 27 cases). Olecranon bursitis was reported in three cases, and disseminated infection was noted in three cases occurring in immunocompromised patients. M. szulgai is more susceptible to standard antimycobacterial agents than are other nontuberculous mycobacteria, notably the Mycobacterium avium complex. Clinical improvement and cure of pulmonary disease can be anticipated when treatment includes at least three drugs effective in in vitro susceptibility tests. Surgical excision appears unnecessary in pulmonary disease but may be indicated in olecranon bursitis.

Anti-Bacterial Agents↗