PubMed Health⌕ Search

Biomedical subjects

G F Brooks

Publications and source records attributed to G F Brooks.

At least 55 records · Page 3Linked to original sources
PubMed1980

In vitro modeling of acute salpingitis caused by Neisseria gonorrhoeae.

Normal human fallopian tube organ culture was used as an in vitro model to study Neisseria gonorrhoeae infections. The effects of various gonococcal colony phenotypes on morphology of the epithelium were studied by scanning electron microscopy. After 30 minutes' incubation, there was striking attachment of piliated transparent phenotypes to the epithelium; however, there was no obvious pathology. After 24 hours' incubation, there were microcolony formation, slight swelling and hyperplasia of the mucosa, and occasional focal necrosis and sloughing of ciliated cells. Tissue from acute salpingitis showed widespread destruction of mucosa, hyperplasia, and crypt formation. Duplication of these findings in vitro may require longer incubation and the addition of other host factors.

Epithelium↗
PubMed1980

Scanning electron microscopy of attachment of Neisseria gonorrhoeae colony phenotypes to surfaces of human genital epithelia.

Attachment of different gonococcal colony phenotypes to explants of human genital tract epithelium was studied by means of scanning electron microscopy and radioisotope-labeled gonococci. Heavily piliated organisms attached in greater numbers than nonpiliated organisms. Gonococci from transparent colony phenotypes attached in higher numbers than gonococci from opaque phenotypes to all tissues studied. Transitional cells from cervical tissues showing a gradual squamocolumnar transition demonstrated more gonococci attached per surface area than either endocervical or fallopian tube epithelium. Squamous epithelium showed the fewest number of attached gonococci. In all tissues, the attachment of the gonococcus was to the tips and surfaces of the microvilli. Gonococcal colony phenotypes as well as the length and location of the cervical transition zone may influence the progression of cervical gonococcal infection to invasive disease.

Cervix Uteri↗
PubMed1980

Comparison of virulence markers of peritoneal and fallopian tube isolates with endocervical Neisseria gonorrhoeae isolates from women with acute salpingitis.

Neisseria gonorrhoeae strains which cause acute salpingitis are presumed to ascend the genital tract from the cervix. Previous studies utilized isolates obtained from endocervical canal cultures, although it was not known if the isolates truly represented the organisms present in the fallopian tubes. In this study, we compared N. gonorrhoeae isolates from endocervical canal cultures with fallopian tube or peritoneal cul-de-sac isolates or isolates from both sites obtained at laparoscopy. Potential virulence markers were studied, including colony phenotype, auxotype, antimicrobial agent susceptibility, protein patterns on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and susceptibility to normal human serum. Six of seven cervical isolates had the same antibiograms and molecular weight for major outer membrane proteins as those of the corresponding peritoneal isolates. Auxotypes also were the same and included prototrophic, proline-requiring, and proline-and-arginine-requiring isolates. The isolates as a group appeared to be very susceptible to the bactericidal action of pooled serum from normal women. Colony phenotypes varied between sites; the fallopian tubecul-de-sac isolates were predominantly of transparent phenotype and piliated. The cervical isolates were either mixtures of equal quantities of opaque and transparent phenotypes or predominantly opaque phenotype. By these markers, patients' N. gonorrhoeae cervical isolates appeared to be the same as their isolates from fallopian tubes except for a difference or shift in colony phenotype.

Anti-Bacterial Agents↗
PubMed1980

Human seminal plasma inhibition of complement.

Recent studies have shown that human seminal plasma contains chemically and biologically distinct factors which inhibit lymphocyte functions and the serum bactericidal and opsonic activities associated with the killing of gram-negative organisms. Because of the direct association between complement action and serum bactericidal and opsonic activities, inhibition of complement may be one of the possible mechanisms of action of seminal plasma immunoinhibitory factors. Complement hemolytic activity was measured for C3 and C4 in serum Neisseria gonorrhoeae and Escherichia coli bactericidal reaction mixtures with and without addition of seminal plasma. In the presence of seminal plasma, where there was no bactericidal action, C3 and titers were reduced to approximately 50% of the titers in the reactions with complement donor serum. The C3 titers were lower than in the reaction mixtures with immune serum and complement donor serum, where N. gonorrhoeae bactericidal activity occurred. Individual human seminal plasma specimens depressed CH50 activity of pooled normal human sera up to 50% of normal levels. There were no differences in inhibition by seminal plasma specimens from normal or vasectomized men. Treatment with seminal plasma depressed the functional activity of complement components C1 and C3 by more than 50%. Seminal plasma also inhibited alternate pathway activity. Cleavage of factor B was demonstrated. The seminal plasma factor which inhibited complement was of low molecular weight. DPF blocked the seminal plasma complement-inhibitory factor. However, amidolytic activity for serine protease substrates could not be demonstrated. It is likely that the seminal plasma complement inhibitor is a protease inhibitor acting singly or in combination.

Absorption↗
PubMed1979

Neisseria meningitidis and Neisseria gonorrhoeae bacteremia associated with C6, C7, or C8 deficiency.

We summarize data from 24 previously described or newly diagnosed cases of homozygous deficiency of the sixth, seventh, or eighth components of complement. Thirteen of 24 patients had at least one episode, and usually two or more episodes of Neisseria meningitidis or Neisseria gonorrhoeae bacteremia, or both. Deficiency of C6, C7, or C8 is a meaningful risk factor for repeated neisserial bacteremia; conversely, hemolytic complement studies are indicated in patients who develop recurrent neisserial infections. When a person with C6, C7, or C8 deficiency is identified, family members should also be studied.

Adolescent↗
PubMed1978

Histoplasmosis in immunosuppressed patients.

Infection with Histoplasma capsulatum in 58 patients whose immune responses were suppressed (Immunosuppressed patients) (16 from the present series and 42 described previously) was analyzed. The most common underlying diseases were Hodgkin's disease (29 per cent), chronic lymphocytic leukemia (19 per cent) and acute lymphocytic leukemia (17 per cent). Sixty-three per cent of the patients had received cytotoxic drugs, and 57 per cent had taken corticosteroids. Widely disseminated infection occurred in 88 per cent of the patients, with predominant involvement of lungs and organs of the reticuloendothelial system. Localized pulmonary infection was present in the remaining patients. The most useful diagnostic method was bone marrow biopsy with microscopic examination for the intracellular yeast form of H. capsulatum. Biopsy of oral lesions, lung, liver and lymph node also proved diagnostically helpful. Growth of H. capsulatum in culture was frequently too slow to be beneficial in diagnosing histoplasmosis in ill patients. Serologic methods were of little diagnostic help in this population of immunosuppressed patients. The response to amphotericin B therapy was excellent (6.7 per cent mortality rate) in those patients in whom the diagnosis was established early and in whom a full course of antifungal therapy could be given. In contrast, the mortality rate in patients who received no antifungal therapy or less than 1 g of amphotericin B was 100 per cent.

Adult↗
PubMed1978

Repeated gonorrhea: an analysis of importance and risk factors.

This study was designed to assess the epidemiological importance of repeated infections due to Neisseria gonorrhoeae and to analyze variables potentially associated with repeated gonorrhea. The retrospective analysis was of 7,347 patients seen during one year, and the prospective study was of a stratified randomly selected sample of 429 patients. The 492 retrospectively identified repeaters constituted 0.06% of the county population and 6.7% of the clinic population. The 492 repeaters had 21.6% of the cases of gonorrhea reported from the county and 29.4% of the cases reported from the clinic. The repeaters tended to be younger than those without repeated infection (P less than 0.001), male (62%), black (81.7%), and residents of areas of lower socioeconomic status than those who were not repeaters (P less than 0.001). Most repeaters (73.5%) had not graduated from high school. Repeaters did not have significantly greater numbers of sex partners (P greater than 0.05) or greater exposure to prostitutes or clients than those who did not have repeated infections and less frequently had sexual contact while symptomatic. Intensive follow-up of the small number of high-risk repeaters and their contacts could result in a major reduction in the number of reported cases of gonorrhea.

Adolescent↗
PubMed1978

Studies on the relationships between serum bactericidal activity and uncomplicated genital infections due to Neisseria gonorrhoeae.

This report concerns the relationships between patients' uncomplicated genital infections due to Neisseria gonorrhoeae and the bactericidal activity of their sera against their infecting organisms. Forty isolates of N. gonorrhoeae and 91 serum samples were obtained from 23 patients with their first or repeated gonococcal infections. Of 32 sera obtained at the time of infection, 14 (44%) were bactericidal for the infecting strains. Of convalescent-phase sera from 27 infections, 12 (44%) were bactericidal; 22%-33% of convalescent-phase sera had increased bactericidal activity when compared with acute-phase sera or sera obtained before infection. Eleven patients developed 17 new infections after sera and negative cultures were obtained; in six (35%) the previously obtained sera were bactericidal but did not prevent infection.

Bacteriological Techniques↗
PubMed1976

Serologic therapy of tetanus in the United States, 1965-1971.

To study the influence of tetanus antitoxins on the outcome of human tatanus, we analyzed data on 545 cases reported to the Center for Disease Control from 1965 through 1971. Patients treated with antitoxin had a significantly lower case-fatality ratio than untreated patients, and the effect of serotherapy was not modified significantly by the age or race of the subjects. Antitoxin of equine origin and human tetanus immune globulin (TIG) were equally effective. The data on the effect of different doses of TIG suggest that 500 units may be as effective as the currently recommended therapeutic dose of 3,000 to 10,000 units. The importance of possible bias introduced by unmeasured factors such as quality of supportive therapy could not be determined, but confounding by 11 recorded potentially confounding factors was minimal.

Adolescent↗
PubMed1976

Clinical correlation of strain differentiation of Neisseria gonorrhoeae.

An in vitro bactericidal assay that utilized a set of 20 typing antisera to Neisseria meningitidis was developed to distinguish differences in strains of Neisseria gonorrhoeae based on patterns of killing. When test conditions were rigidly standardized, the method was sensitive and reproducible. Strains of gonococci from 20 unrelated patients had 20 different patterns of killing. Sets of strains of N. gonorrhoeae that were likely to be identical on the basis of clinical histories were examined. Organisms isolated from consorts reacted in an identical fashion in seven of nine instances. The two nonidentical sets of strains from consorts were also different in their antibiotic sensitivity patterns. The case history of one patient suggested that one of these strains was obtained from a source of infection other than the named consort, and a second patient was reinfected with a strain from her partner four months later. Four sets of strains were cultured at different intervals after appropriate therapy. On the basis of bactericidal patterns, the strains from one patient were the same, a finding that suggested treatment failure; the strains from other patients were not identical, a fact that suggested that patients were reinfected.

Antigens, Bacterial↗
PubMed1976

Bactericidal and opsonic activity against Neisseria gonorrhoeae in sera from patients with disseminated gonococcal infection.

Bactericidal and opsonic activities in convalescent-phase sera from patients with disseminated gonococcal infection (DGI) were analyzed with use of the patients' infecting strains and other strains of Neisseria gonorrhoeae. Serum from a patients with C8 deficiency was opsonic for her first DGI isolate grown on solid medium or in chick embryos; with added complement the serum was bactericidal (at a dilution of 1:320). Her serum was not bactericidal for nine other isolates from patients with DGI. Only one of the other patients with DGI had detectable serum bactericidal activity (dilution, 1:2,5) against her own isolate; this patient's serum was also active against one other DGI isolate. Opsonization was detectable only in sera that were potentially bactericidal and could be distinguished from bactericidal activity only with C8-deficient serum. The isolates from patients with DGI were of an auxotype different from that of most other gonococci, and most of the isolates tested were not killed by sera from patients with uncomplicated gonorrhea, even though these wera killed other gonococci. Thus, isolates from patients with DGI appeared to be significantly different from other gonococcal isolates.

Antibodies, Bacterial↗
PubMed1976

Phospholipid composition and phospholipase A activity of Neisseria gonorrhoeae.

Exponential-phase cells of Neisseria gonorrhaeae 2686 were examined for phospholipid composition and for membrane-associated phospholipase A activity. When cells were harvested by centrifugation, washed, and lyophilized before extraction, approximately 74% of the total phospholipid was phosphatidylethanolamine, 18% was phosphatidylglycerol, 2% was cardiolipin, and 10% was lysophosphatidylethanolamine. However, when cells still suspended in growth medium were extracted, the amount of lysophosphatidylethanolamine decreased to approximately 1% of the phospholipid composition. This suggests that a gonococcal phospholipase A may be activated by conditions encountered during centrifugation and/or lyophilization of cells preceding extraction. Phospholipase A activity associated with cell membranes was assayed by measuring the conversion of tritiated phosphatidylethanolamine to lysophosphatidylethanolamine. Optimal activity was demonstrated in 10% methanol at pH 8.0 to 8.5, in the presence of calcium ions. The activity was both detergent sensitive and thermolabile. Comparisons of gonococcal colony types 1 and 4 showed no significant differences between the two types with respect to either phospholipid content or phospholipase A activity.

Calcium↗
PubMed1976

Human deficiency of the eighth component of complement. The requirement of C8 for serum Neisseria gonorrhoeae bactericidal activity.

The serum of a 23-yr-old woman with prolonged disseminated gonococcal infection syndrome failed to normally promote hemolysis of sensitized sheep red blood cells (RBC). The patient's serum was deficient in the eight component of complement (C8) as determined by functional assays, immunoelectrophoresis, and quantitative immunoprecipitation. Functional titers of each of her other complement components were normal. No serum inhibitors of C8 were detected. The patient's serum supported activation of both the classical and alternate complement pathways. Her fresh serum lacked any bactericidal activity against Neisseria gonorrhoeae, but addition of purified C8 or complement donor serum restored bactericidal activity as well as RBC hemolytic activity. Her serum gave normal opsonization of yeast particles and staphylococci and had normal capacity to coat sensitized RBC with C8 and C4 and to generate chemotactic activity. No defects were observed in the patient's blood coagulation mechanisms. Complement-mediated bacterial lysis may be important in human defense against bacteremic Neisseria infections.

Adult↗
PubMed1976

Parameters of normal polymorphonuclear cell function in patients with repeated gonococcal infections.

The response to phagocytic stimuli was tested for polymorphonuclear (PMN) cells from gonorrhea repeaters, first-time infected patients, and never-infected controls. PMN function was assessed by measuring quantitative leukocyte iodination, glucose-1-C oxidation, and phagocytosis and killing of Staphylococcus aureus 502A. No significant differences in PMN function were noted for the three groups studied. However, white patients had significantly greater leukocyte iodination than black patients (p less than 0.05) and males tended to have greater leukocyte iodination than females (p less than 0.02). It is concluded that PMN cells from gonorrhea repeaters, first-time infected patients, and never-infected controls respond equally well to in vitro phagocytic stimuli. This implies that a significant defect in PMN cell function should not be implicated as a reason for the apparent susceptibility of gonorrhea repeaters to multiple genital gonococcal infections.

Blood Bactericidal Activity↗