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Biomedical subjects

R F Schell

Publications and source records attributed to R F Schell.

At least 91 records · Page 5Linked to original sources
PubMed1987

Treponema pallidum attachment to surface and matrix proteins of cultured rabbit epithelial cells.

Treponema pallidum strain Nichols adheres readily to rabbit epithelial cells (SF1Ep) in tissue culture. We examined a variety of sugars for their ability to inhibit attachment. Mannose, galactose, and N-acetylgalactosamine showed minor but reproducible inhibition of attachment at high concentrations, whereas sialic acid was highly inhibitory even at low concentrations. Whole-cell lysates of SF1Ep cells contained a large number of glycoproteins, which might be related to the sialic acid-inhibitable attachment. When the cells and extracellular matrix were fractionated, only a few proteins were found in the matrix fraction. They included a 220-kilodalton (kDa) protein, shown by immunoblotting to be fibronectin, and an approximately 90-kDa protein (both were isolated on SDS-PAGE gels). When nitrocellulose replicas of these SDS-PAGE gels were exposed to 125I-labeled T. pallidum, adherence was mainly to the 90-kDa protein.

Animals↗
PubMed1987

Evaluation of a quantitative fluorescence immunoassay (FIAX) for detection of serum antibody to Borrelia burgdorferi.

A quantitative, indirect, fluorescence immunoassay (FIAX; Whittaker Bioproducts, Inc.) was compared with the conventional indirect fluorescent-antibody test for detection of serum antibody to Borrelia burgdorferi. FIAX correlated well with the indirect fluorescent-antibody test (r = 0.72). FIAX is a convenient and dependable means of measuring serum antibody to B. burgdorferi.

Antibodies, Bacterial↗
PubMed1987

Identification of Yersinia spp. with the API 20E system.

The ability of the API 20E system to identify 105 clinical isolates of Yersinia spp. was compared with those of conventional biochemical tests at 28 and 37 degrees C. Elimination of the Voges-Proskauer test (recorded as a negative result) increased the percentage of correct identifications for Yersinia spp. from 66 to 93% when the API 20E strips were incubated at 28 degrees C.

Bacteriological Techniques↗
PubMed1986

Effect of immune serum and its immunoglobulin fractions on hamsters challenged with Treponema pallidum ssp. pertenue.

Passive transfer of frambesial immune serum is capable of conferring complete protection on hamsters against challenge with Treponema pallidum ssp. pertenue. Treponemicidal activity in the pooled immune serum is relatively high. Immune serum and its immunoglobulin fractions, especially IgG2, also killed T. pallidum ssp. pertenue in vitro. Treponemicidal activity was present only when immune serum was administered to hamsters within a short time (three days) of frambesial challenge. By contrast, administration of pooled immune serum to hamsters infected for more than one week failed to reduce the number and size of lesions and the weight and number of treponemes in the lymph nodes. These results suggest that hamsters can develop the humoral components necessary to protect them against frambesial challenge, but these components are unable to destroy treponemes at the primary foci of infection.

Animals↗
PubMed1986

Evaluation of the 10-micrograms clindamycin disk for susceptibility testing of anaerobes by the aerobically incubated thioglycolate broth disk method.

The reliability of the 10-micrograms clindamycin disk was evaluated for susceptibility testing of anaerobes by the aerobic thioglycolate broth disk method. A good correlation between the aerobic thioglycolate broth disk method and the reference agar dilution procedure of the National Committee for Clinical Laboratory Standards was obtained by using a 4-microgram/ml breakpoint. Improved correlation was obtained when the medium of the National Committee for Clinical Laboratory Standards was buffered.

Bacteria, Anaerobic↗
PubMed1986

Antimicrobial activity of cefmetazole compared with those of other cephalosporins.

The antimicrobial activity of cefmetazole was compared with those of cefmenoxime, ceftizoxime, cefamandole, cefoperazone, cefotaxime, cephalothin, and latamoxef. In general, the activity of cefmetazole was less than those of the other cephalosporins. The in vitro activity of cefmetazole suggests that it will not prove useful as a broad-spectrum antimicrobial against gram-positive and gram-negative pathogens.

Cefmetazole↗
PubMed1985

The activity of ceftazidime compared with those of aztreonam, newer cephalosporins and Sch 29482 against nonfermentative gram-negative bacilli.

The activity of ceftazidime was compared with those of aztreonam, newer cephalosporins and Sch 29482 against nonfermentative gram-negative bacilli. Ceftazidime was consistently more active (MIC less than or equal to 8 micrograms) against the nonfermenters. Only Flavobacterium odoratum, F. spp., Pseudomonas alcaligenes, P. maltophilia and P. stutzeri demonstrated substantial resistance (MIC90 greater than or equal to 64 micrograms) to ceftazidime. Sch 29482 and ceftriaxone also exhibited good activity (MIC90 less than or equal to 8 micrograms) against many of the nonfermenters. The broad activity of ceftazidime, however, makes it a potentially more useful therapeutic agent against these microorganisms.

Anti-Bacterial Agents↗
PubMed1985

A comparative study of gentamicin and netilmicin in the treatment of gram-negative infections.

Netilmicin is active in vitro against a wide variety of gram-negative bacteria, including certain gentamicin-resistant isolates, and Staphylococcus aureus. This study presents the results of a prospective, randomized, double-blinded protocol designed to determine the relative efficacy and toxicity of netilmicin and gentamicin in the therapy of gram-negative infections. The demographic make-up of both treatment groups was similar. Cure rates were 96.7 percent with netilmicin and 94.4 percent with gentamicin. Possible transient nephrotoxicity developed in nine patients receiving netilmicin and in eight patients receiving gentamicin.

Adult↗
PubMed1984

Cefmenoxime. Clinical, bacteriologic, and pharmacologic studies.

Cefmenoxime, a new semisynthetic third-generation cephalosporin, was evaluated in 105 patients (45 men and 60 women) with the following infections: skin or skin structure (33), pulmonary (22), urinary tract (30), and septicemia (20). Forty-two infections were hospital-acquired, 85 patients had underlying diseases, 29 patients required concomitant surgery, and 32 patients had positive results of blood culture. Cefmenoxime dosages ranged from 4 to 12 g per day intravenously for one and a half to 51 days. Cultures revealed 183 organisms in the 105 patients. Minimal inhibitory concentrations were obtained for cefmenoxime, cefoperazone, cefotaxime, cefamandole, cefoxitin, and moxalactam. Cefmenoxime and cefotaxime exhibited nearly equivalent activities against all organisms tested and were the most active agents tested against all aerobic and facultative organisms except Staphylococcus aureus. Mean serum peak and trough levels obtained after 2 g every six hours were 84.1 micrograms/ml (peak), 8.3 micrograms/ml (trough); and after 2 g every four hours, 106 micrograms/ml (peak) and 10.9 micrograms/ml (trough). Of 105 infections, 86 were clinically cured, three were not cured, and 16 were not evaluable. Safety studies revealed 24 transient reactions in 23 patients including eosinophilia, diarrhea, leukopenia, rash, elevated liver enzyme levels, Antabuse effect, and phlebitis. On the basis of these clinical and in vitro results, cefmenoxime is a safe drug for the treatment of infections caused by gram-negative and gram-positive aerobic organisms.

Adult↗
PubMed1984

Antimicrobial activities of BMY-28142, cefbuperazone, and cefpiramide compared with those of other cephalosporins.

The antimicrobial activities of BMY-28142, cefbuperazone (BMY-25182; formerly T-1982), and cefpiramide (WY-44635; formerly SM-1652) were compared with those of cefmenoxime, cefoperazone, cefotaxime, ceftizoxime, and moxalactam. BMY-28142 was the most active cephalosporin against the majority of aerobic and facultatively anaerobic microorganisms studied. Its spectrum of activity was very similar to that of cefotaxime. However, BMY-28142, cefbuperazone, cefmenoxime, cefotaxime, ceftizoxime, and moxalactam were equivalent in activity and rate of killing against members of the family Enterobacteriaceae. Cefpiramide was considerably less active than the other cephalosporins against the Enterobacteriaceae.

Bacteria↗
PubMed1984

Cobra venom factor abrogates passive humoral resistance to syphilitic infection in hamsters.

Cobra venom factor, an agent commonly used to deplete complement, lowered the resistance of hamsters to infection with Treponema pallidum subsp. endemicum , as shown by a more rapid development of cutaneous lesions in infected animals treated with cobra venom factor than in infected, untreated animals. Cobra venom factor also abrogated the passive transfer of resistance by injection of serum from syphilitic immune hamsters. These results indicate that complement influences the pathogenesis of treponemal infection.

Animals↗
PubMed1984

Monoclonal antibody analysis of specific antigenic similarities among pathogenic Treponema pallidum subspecies.

Murine monoclonal antibodies directed against a 47,000-dalton immunodominant surface-exposed antigen of Treponema pallidum subsp. pallidum (Nichols) were isolated. These monoclonal antibodies cross-reacted with analogous 47,000-dalton antigens of two other virulent treponemes, T. pallidum subsp. pertenue and T. pallidum subsp. endemicum (Bosnia A), as determined by radioimmunoassay and immunoblot analyses. Immunoelectron microscopy confirmed that the 47,000-dalton antigen of T. pallidum subsp. pallidum was a surface-associated cellular component. Surface binding assays and immunoelectron microscopic studies also suggested that the analogous 47,000-dalton antigenic component of T. pallidum subsp. pertenue may not have been oriented toward the bacterial surface in the same way as the T. pallidum subsp. pallidum antigen or that the relevant antigenic determinant(s) may not have been exposed to the outer surface in the same way. The significance of this antigen relative to its apparent conservation among pathogenic treponemes and its possible diagnostic and vaccinogenic potentials are discussed.

Animals↗
PubMed1984

The activity of ceftazidime, other beta-lactams, and aminoglycosides against Pseudomonas aeruginosa.

The inhibitory and bactericidal activities of ceftazidime, cefoperazone, ceftriaxone, piperacillin, and five aminoglycosides were determined against 50 tobramycin-susceptible and 25 multidrug-resistant isolates of Pseudomonas aeruginosa. Ceftazidime was the most active beta-lactam and tobramycin the most active aminoglycoside. The combination of piperacillin and tobramycin was synergistic in most cases. The combination of cephalosporin and tobramycin showed mostly addition or indifference, as did combination of two beta-lactams. No antagonism was observed.

Aminoglycosides↗
PubMed1984

Activity of eleven antimicrobial agents against methicillin-, methicillin- and rifampin-resistant Staphylococcus aureus.

Activity of eleven antimicrobial agents against methicillin-, methicillin- and rifampin-resistant Staphylococcus aureus was studied using a microtiter broth dilution technique. Coumermycin was the most active agent. Vancomycin, rifampin, fusidic acid and N-formimidoyl-thienamycin showed excellent activity against methicillin-resistant St. aureus (MRSA). Antimicrobial susceptibility pattern was similar for MRSA and methicillin- and rifampin-resistant St. aureus. 8% of MRSA were resistant to trimethoprim and sulfamethoxazole.

Anti-Bacterial Agents↗
PubMed1984

Activity of cefsulodin, other beta-lactams, and aminoglycosides against Pseudomonas aeruginosa.

Cefsulodin was the most active of the cephalosporins and exhibited 4-16 times more activity than carbenicillin or ticarcillin against 50 clinical isolates of Pseudomonas aeruginosa. Azlocillin and piperacillin showed good activity, while tobramycin was the most effective aminoglycoside. The activity of cefsulodin was unaltered by increases in inocula, but resistance was induced easily. When combined with gentamicin, no synergistic or antagonistic activity was observed against multiply resistant isolates.

Aminoglycosides↗
PubMed1984

Inhibition of macrophage C3b-mediated ingestion by syphilitic hamster T cell-enriched fractions.

Macrophages are important for host defense against syphilitic infection. Our results show that C3b-mediated ingestion (C3bMI), a characteristic of activated macrophages, was inhibited in vitro by nonadherent cells from hamsters infected with Treponema pallidum subspecies endemicum. When macrophage target cells from normal, syphilitic, or lipopolysaccharide-treated animals were co-cultured with nonadherent cells derived from normal or syphilitic hamsters, noticeable differences were detected. Nonadherent syphilitic cells significantly suppressed macrophage C3bMI, whereas normal nonadherent cells displayed little or no suppressive activity. In general, macrophage C3bMI was reduced by nonadherent cells obtained throughout the course of syphilitic infection, although it eventually began to recover. The syphilitic nonadherent cells with maximum suppressive effect were those obtained from hamsters infected for 3 to 6 wk. The addition of treponemal antigens additionally inhibited C3bMI. The inhibitory effect of syphilitic nonadherent cells on either lipopolysaccharide-treated or syphilitic macrophages was sustained even when the nonadherent cells were removed from the cultures, and the effect continued for at least 72 hr thereafter. Fractionation of syphilitic nonadherent cell populations by two independent methods produced T cell-enriched preparations with significantly more suppressive activity than non-T cell-enriched preparations. These observations may account for the chronicity of syphilitic infection.

Adult↗
PubMed1983

Antimicrobial activity of cefmenoxime compared with those of other cephalosporins.

The antimicrobial activity of cefmenoxime was compared with those of cefamandole, cefoperazone, cefotaxime, cephalothin, and moxalactam. In general, the activity of cefmenoxime was equivalent to those of the other cephalosporins. Cefmenoxime appears to be a potent antimicrobial agent against most gram-negative microorganisms other than Pseudomonas aeruginosa and Acinetobacter spp.

Bacteria↗