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Biomedical subjects

R F Schell

Publications and source records attributed to R F Schell.

At least 73 records · Page 4Linked to original sources
PubMed1990

Effects of bovine serum albumin on the ability of Barbour-Stoenner-Kelly medium to detect Borrelia burgdorferi.

The ability of decreasing inocula of Borrelia burgdorferi to grow in otherwise identical Barbour-Stoenner-Kelly (BSK) media containing different lots of bovine serum albumin (fraction V) was determined. These media differed significantly in ability to detect B. burgdorferi. Some BSK media required inocula of 2 x 10(5) organisms per ml for detection, while other media could stimulate growth after inoculation with less than 2 organisms per ml. In addition, organisms from the less sensitive BSK media were thinner, longer, and less tightly coiled. The endpoint dilutions of indirect fluorescent-antibody titers, especially immunoglobulin M, exhibited up to 16-fold decreases, and both immunoglobulin G and M titers were more difficult to interpret with diagnostic slides prepared from some longer, thinner B. burgdorferi. These results demonstrate that, when performing laboratory investigations which rely on B. burgdorferi, it is essential that the quality of the BSK medium be determined.

Antibodies, Bacterial↗
PubMed1990

Rapid detection of bacteria in cerebrospinal fluid by immunofluorescence staining on membrane filters.

A filter-fluorescent-antibody (FFA) staining procedure was developed for detection of bacteria in cerebrospinal fluid (CSF). The sensitivity of this procedure was determined and compared with that of the slide Gram stain of centrifuged samples, latex agglutination, and a previously developed filter Gram stain. Serial 10-fold dilutions of filter-sterilized CSF seeded with logarithmic-phase organisms were examined by each method and cultured to determine colony-forming bacteria. The bacteria included Haemophilus influenzae type b; Neisseria meningitidis group B, C, and W135; Streptococcus pneumoniae types 6A and 23F; and group B Streptococcus species. FFA was found to be equal in sensitivity to the filter Gram stain (P greater than 0.30). Both filter-staining procedures had greater sensitivity than the slide Gram stain of centrifuged sediment (P less than 0.02) and latex agglutination (P less than 0.0001). Addition of human leukocytes at a concentration of 5 to 10 cells per oil immersion field did not decrease sensitivity of the FFA procedure, although background fluorescence increased. FFA is a rapid and dependable procedure for detection of low numbers of bacteria in CSF. Evaluation of FFA with clinical specimens is needed.

Bacteria↗
PubMed1990

Evaluation of two commercial procedures for rapid identification of Neisseria gonorrhoeae using a reference panel of antigenically diverse gonococci.

Two commercial tests for the rapid identification of Neisseria gonorrhoeae were evaluated. Two hundred seventy-nine organisms were tested, including 202 strains of N. gonorrhoeae. The Syva MicroTrak test results were less subjective but required a fluorescence microscope. The Phadebact Monoclonal GC OMNI Test required modification of the manufacturer's interpretive instructions in order to avoid cross-reactions, but it was a practical test. Specificities of both tests were 100%. Sensitivities of the Phadebact Monoclonal GC OMNI and Syva MicroTrak tests were 100% and approximately 100%, respectively.

Agglutination Tests↗
PubMed1989

Phagocytosis of Treponema pallidum pertenue by hamster macrophages on membrane filters.

The role of the macrophage in destruction of virulent treponemes is disputed. A major obstacle has been the inability to demonstrate quantitative phagocytosis of treponemes by macrophages. Treponema pallidum pertenue was attached to polycarbonate filters for assessment of treponemal phagocytosis by macrophages. The disappearance of treponemes due to phagocytosis was measured by enumeration with immunofluorescence. Resident and lipopolysaccharide-activated macrophages were found to phagocytize treponemes equally well. The phagocytosis of killed treponemes by macrophages was enhanced by opsonization with immune serum. Macrophages successfully phagocytized Staphylococcus aureus organisms when they were incubated on filters under identical conditions. Treatment of macrophages with cytochalasin B, a known inhibitor of phagocytosis, prevented the disappearance of treponemes and phagocytosis of S. aureus. In addition, fluorescent treponemal debris was observed only inside macrophages cultured with treponemes. These results demonstrate that macrophages can phagocytize pathogenic treponemes on polycarbonate filters.

Animals↗
PubMed1989

Development of a rapid method for determining the susceptibility of Mycobacterium tuberculosis to isoniazid using the Gen-Probe DNA Hybridization System.

A rapid test was developed for determining the susceptibility of Mycobacterium tuberculosis to isoniazid by using nucleic acid hybridization. The method was based on quantification of total mycobacterial rRNA hybridized to a 125I-labeled DNA probe in the absence and presence of various concentrations of isoniazid. The radioactive hybridized complex was isolated by adsorption to hydroxyapatite crystals and measured in a gamma counter. The susceptibilities of four reference strains and 20 clinical isolates were compared by the Gen-Probe DNA Hybridization System and the critical concentration method. Overall agreement between the two methods was excellent. Results were obtained with the DNA probe after 3 to 5 days of incubation instead of the 14 to 21 days required for the critical concentration method. These findings indicate that susceptibility testing of M. tuberculosis by nucleic acid hybridization has merit for the clinical laboratory. Additional studies are needed to determine the efficacy of the DNA probe method for determining the susceptibility of M. tuberculosis to other antimycobacterial agents and its correlation with clinically significant levels of resistance.

Culture Media↗
PubMed1989

Efficacy of the urinary bladder for isolation of Borrelia burgdorferi from naturally infected, wild Peromyscus leucopus.

The efficacy of culturing urinary bladder tissue for Borrelia burgdorferi from naturally infected, wild Peromyscus leucopus mice was determined. The urinary bladder cultures were as efficient as spleen, kidney, and blood tissue cultures. The rapid B. burgdorferi isolation (mean, 6 days) from mouse urinary bladders should aid in defining new Lyme disease foci.

Animals↗
PubMed1989

The pathologist's view of Lyme disease.

Lyme disease is a multisystem disease caused by the spirochete Borrelia burgdorferi and is transmitted to humans primarily through Ixodid ticks. The clinical spectrum of the disease is continuing to expand while in its wake the pathology and histopathologic manifestations are being uncovered. We review the pathology of Lyme disease in man beginning with the tick bite. We present the pathologic changes of the rash, erythema migrans, as well as the neurologic, cardiac, and arthritic changes of the disease. We can expand our understanding of the immunobiology of Lyme disease by studying the interactions of B. burgdorferi in an experimental animal model.

Humans↗
PubMed1989

Histopathology of Lyme arthritis in LSH hamsters.

The authors studied the histopathologic evolution of arthritis in nonirradiated and irradiated hamsters infected with Borrelia burgdorferi. Nonirradiated hamsters injected in the hind paws with B. burgdorferi developed an acute inflammatory reaction involving the synovium, periarticular soft tissues, and dermis. This acute inflammatory reaction was short-lived and was replaced by a mild chronic synovitis as the number of detectable spirochetes in the synovium, periarticular soft tissues, and perineurovascular areas diminished. Exposing hamsters to radiation before inoculation with B. burgdorferi exacerbated and prolonged the acute inflammatory phase. Spirochetes also persisted longer in the periarticular soft tissues. A major histopathologic finding was destructive and erosive bone changes of the hind paws, which resulted in deformation of the joints. These studies should be helpful in defining the immune mechanism participating in the onset, progression, and resolution of Lyme arthritis.

Animals↗
PubMed1988

Antimicrobial susceptibilities of Bordetella species isolated in a Multicenter Pertussis Surveillance Project.

MICs for 90% (MIC90s) of 75 Bordetella pertussis strains for amoxicillin, erythromycin, rifampin, and sulfamethoxazole-trimethoprim were 1, less than or equal to 0.12, 1, and 4 micrograms/ml, respectively. Susceptibility rates were all greater than or equal to 93%. Only 17% of the strains were susceptible to tetracycline. The MIC90s of ciprofloxacin, enoxacin, norfloxacin, ofloxacin, and roxithromycin were less than or equal to 0.06, 0.5, 0.25, 0.12, and 0.5 micrograms/ml, respectively. For B. parapertussis, the MIC90s were 16-fold higher with amoxicillin and rifampin and 2- to 4-fold higher with the fluoroquinolones and roxithromycin.

Adolescent↗
PubMed1988

Induction of lyme arthritis in LSH hamsters.

In studies of experimental Lyme disease, a major obstacle has been the unavailability of a suitable animal model. We found that irradiated LSH/Ss Lak hamsters developed arthritis after injection of Borrelia burgdorferi in the hind paws. When nonirradiated hamsters were injected in the hind paws with B. burgdorferi, acute transient synovitis was present. A diffuse neutrophilic infiltrate involved the synovia and periarticular structures. The inflammation was associated with edema, hyperemia, and granulation tissue. Numerous spirochetes were seen in the synovial and subsynovial tissues. The histopathologic changes were enhanced in irradiated hamsters. The onset and duration of the induced swelling were dependent on the dose of radiation and the inoculum of spirochetes. Inoculation of irradiated hamsters with Formalin-killed spirochetes or medium in which B. burgdorferi had grown for 7 days failed to induce swelling. This animal model should prove useful for studies of the immune response to B. burgdorferi and the pathogenesis of Lyme arthritis.

Animals↗
PubMed1988

Characterization of an unclassified microaerophilic bacterium associated with gastroenteritis.

Four isolates of an unclassified microaerophilic bacterium resembling Campylobacter species were characterized by growth requirements, microscopic examination, biochemical characteristics, antimicrobial susceptibility tests, and protein profile analysis. The unclassified isolates were differentiated from Campylobacter jejuni, Campylobacter coli, Campylobacter fetus subsp. fetus, Campylobacter laridis, Campylobacter pylori, and an ovine isolate. The bacterium was fusiform shaped with a corrugated surface due to the presence of periplasmic fibers and had multiple bipolar flagella. Biochemically, the bacterium was separated from the Campylobacter controls by its negative catalase reaction, negative nitrate reduction, and no growth in 1% glycine. It was also resistant to ampicillin. Protein profile analysis demonstrated nine major protein bands present in the unclassified isolates that were absent in the Campylobacter controls. The bacterium also differed from the ovine isolate by its negative catalase reaction, rapid urea hydrolysis, and susceptibility to clindamycin, erythromycin, and tetracycline. Our results showed that the unclassified bacterium was distinct from the recognized Campylobacter species.

Animals↗
PubMed1988

Case report of an unclassified microaerophilic bacterium associated with gastroenteritis.

An unusual microaerophilic gram-negative bacterium was isolated from the stools of two individuals presenting with chronic diarrhea. This bacterium resembled Campylobacter species by colonial morphology and biochemical reactions. However, microscopic examination revealed a fusiform rod with a corrugated surface, rather than a spiral rod. This is the first reported isolation of this bacterium from humans.

Adult↗
PubMed1988

Borrelia burgdorferi infection surrounding La Crosse, Wis.

This investigation defined the extent of Borrelia burgdorferi infection surrounding La Crosse, Wis. White-footed mice, Peromyscus leucopus or P. maniculatis, were captured from sites in Wisconsin, Minnesota, and Iowa and cultured for B. burgdorferi to define the local boundaries of the midwestern Lyme disease area. All foci of B. burgdorferi infection (N1, N2, N3, and N4) were located north of interstate highway 90 except focus S2, which was south of the highway near Fort McCoy, Wis. The interstate highway may have been a barrier to deer movement which slowed the southward dispersal of Ixodes dammini. B. burgdorferi was isolated from 12 (63%) of the mice captured from site N4, which was adjacent to the western border of Fort McCoy. Unexpectedly, no B. burgdorferi-infected mice were isolated at site N0, located north of interstate highway 90 and enclosed by areas in which B. burgdorferi infection is endemic. This site is surrounded by natural barriers which may have slowed the spread of I. dammini by deer. The Wisconsin area in which B. burgdorferi is endemic should now include the surrounding area north of interstate highway 90 west from Fort McCoy to the Mississippi River. Additional studies are needed to define the rapidity, limits, and means of I. dammini dispersal into southern Wisconsin.

Animals↗
PubMed1988

Comparison of modified Bordet-Gengou and modified Regan-Lowe media for the isolation of Bordetella pertussis and Bordetella parapertussis.

Culture and fluorescent-antibody methods for detection of Bordetella species were evaluated by two state public health laboratories. Field-inoculated plates of Regan-Lowe agar medium were most useful if incubation was initiated on the day of collection. Regan-Lowe and Bordet-Gengou media were comparable for subculturing nasopharyngeal specimens that were transported and enriched in half-strength Regan-Lowe agar. Maximum sensitivity was achieved when the media were used in parallel. Fluorescent-antibody-stained smears of nasopharyngeal specimens were more sensitive for detection of Bordetella pertussis than for detection of Bordetella parapertussis. The fluorescent-antibody method, however, was too insensitive for use without culture.

Bordetella↗
PubMed1988

Rapid method for the differentiation of gram-positive and gram-negative bacteria on membrane filters.

Microfiltration has become a popular procedure for the concentration and enumeration of bacteria. We developed a rapid and sensitive method for the differentiation of gram-positive and gram-negative bacteria, utilizing a polycarbonate membrane filter, crystal violet, iodine, 95% ethanol, and 6% carbol fuchsin, that can be completed in 60 to 90 s. Gram reactions of 49 species belonging to 30 genera of bacteria were correctly determined by the filter-Gram stain. The sensitivities of the filter-Gram stain and conventional slide-Gram stain were compared by testing dilutions of Escherichia coli, Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae suspensions in the presence and absence of whole human blood. The filter-Gram stain was approximately 100-fold more sensitive than the slide-Gram stain. The filter-Gram stain detected 2 to 100 bacteria, whereas the slide-Gram stain failed to detect less than 1,000 bacteria. The sensitivities of the methods were not significantly altered by the addition of whole human blood to the dilutions of bacteria tested. The filter-Gram stain could be a useful tool for the examination of body fluids with very low numbers of bacteria.

Blood↗
PubMed1987

Epidemiologic study of canine blastomycosis in Wisconsin.

An epidemiologic study was designed to investigate the increasing number of cases of canine blastomycosis being reported in Wisconsin. From January 1980 through July 1982, 200 cases of canine blastomycosis from 39 Wisconsin counties were examined to assess epidemiologic and environmental aspects of this disease. Based on a survey of 176 dog owners, principal disease characteristics for canine blastomycosis were anorexia, lethargy, shortness of breath, chronic cough, and weight loss. The greatest number of cases of canine blastomycosis was in the northwest, north central, northeast, central, and southeast regions of Wisconsin. The northeast and central regions were determined to be new enzootic areas. Sporting breeds accounted for the largest percentage of cases among the various breeds of dogs in Wisconsin. Most of the affected dogs were 3 years old or younger and there was no apparent sexual predilection. Canine blastomycosis was diagnosed more frequently from late spring through late fall. Enzootic areas, except for the southeast region of Wisconsin, were located where the soil was sandy and acid. The results of this study suggested a possible association of enzootic areas with waterways, especially impoundments.

Animals↗