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Biomedical subjects

M Shayegani

Publications and source records attributed to M Shayegani.

52 records · Page 3Linked to original sources
PubMed1978

Evaluation of the API 20E system for identification of nonfermentative Gram-negative bacteria.

The API 20E system for Enterobacteriaceae, recently broadened to include identification of nonfermentative gram-negative bacteria, was evaluated and compared with the conventional method for complete identification of 221 nonfermenters, which were well distributed into 48 species or biotypes and included organisms not listed in the API 20E data base. The results of 16 tests common to both systems were in close agreement. The API 20E system correctly identified 71 (43%) of the 165 organisms included in the API 20E data base. However, almost 90% of Acinetobacter calcoaceticus, three species of Pseudomonas, and Bordetella bronchiseptica were correctly identified to species.

Bacteriological Techniques↗
PubMed1977

A scheme for identification of nonfermentative gram-negative bacteria.

A scheme was designed to speed the identification of 50 nonfermentative gram-negative bacteria to genus, species, and biotype using a minimal numer of biochemical tests. When the scheme was evaluated in our laboratory, one technologist identified 93.6% of 188 known isolates (46 species). Later another technologist, given 161 of the same isolates (46 species) as unknowns, identified 91.9%. The isolates that were misidentified in both cases were atypical organisms with aberrant biochemical reactions, plus 1 typical organism with a delayed oxidation of glucose.

Bacteriological Techniques↗
PubMed1975

Nonspecific resistance to Escherichia coli in mice.

Nonspecific cell-mediated immunity to a relatively virulent strain of Escherichia coli was studied in mice infected with Staphylococcus aureus and elicited with specific antigens. The infected and elicited mice were protected against as intraperitoneal challenge by E. coli for an observation period of 7 days, whereas normal mice, given the same number of bacteria, died within 18 to 24 h. However, the amount of time elapsing between elicitation and challenge greatly affected the rate of protection. Little or no protection was observed in mice injected with S. aureus but not elicited or in mice injected with staphylococcal antigens but not infected with staphylococci.

Animals↗
PubMed1975

Evaluation of the R/B and Minitek systems for identification of Enterobacteriaceae.

The R/B and Minitek systems for the identification of Enterobacteriaceae were evaluated, and the results were compared with those obtained by conventional methods. Both systems were rapid and allowed correct identification of about 85% of the 294 isolates (23 species) examined. The individual biochemical reactions showed an overall agreement of 92.6% and 93.1% for the R/B and Minitek systems, respectively.

Classification↗
PubMed1975

Evaluation of the enteric analyzer for identification of Enterobacteriaceae.

The reliability of the Enteric Analyzer for identification of Enterobacteriaceae was evaluated using biochemical results previously obtained for 291 organisms with the conventional, R/B, and Minitek systems. The instrument correctly identified 77.3% of the organisms using conventional system results, 74.2% using R/B results, and 60.5% using Minitek results. The low rate of identification with the conventional system occurs primarily because the instrument is not programmed to consider delayed biochemical reactions. The arbitrary use of 90% and 99% probabilities for test reactions also contributes to a lower percentage of identification. The Enteric Analyzer does not replace the judgment of experienced personnel in the identification of atypical bacteria, but it may prove helpful in speeding up final computer identification of typical microorganisms.

Classification↗
PubMed1974

Specific and nonspecific cell-mediated resistance to influenza virus in mice.

We found that influenza virus had the capacity to replicate in the peritoneal macrophages of normal mice, as revealed by the development of hemadsorption and the appearance intracellularly of S and V antigens. Cell-mediated resistance was studied in mice infected with influenza virus or a bacterial sytem of induction-elicitation. In the homologous system, mice were injected intraperitoneally or exposed by aerosol to a sublethal dose of an egg-adapted swine strain of influenza virus. In the heterologous system, they were infected repeatedly with Staphylococcus aureus and elicited by subcutaneous or aerosol administration of staphylococcal antigens. The peritoneal macrophages from mice specifically or nonspecifically immunized were significantly more resistant than those from normal mice. Also longer survival to in vivo challenge by the mouse-adapted virus, as compared with normal mice, was indicated in bacterially stimulated mice.

Aerosols↗
PubMed1973

Lack of detectable circulating interferon in mice protected against vaccinia virus by induction and elicitation with bacterial systems.

Mice which had been subjected to mycobacterial infection and specific elicitation were bled from the orbital sinus at the time the mice were challenged intravenously with vaccinia virus. Assays of the sera were negative for interferon. Sera of rabbits sensitized with staphylococci and elicited by Staphage Lysate also lacked detectable circulating interferon.

Journal Article↗
PubMed1970

Failure of Immune Sera to Enhance Significantly Phagocytosis of Staphylococus aureus: Nonspecific Adsorption of Phagocytosis-Promoting Factors.

Serum from rabbits immunized with either heat-killed or live nonencapsulated Staphylococcus aureus failed further to enhance phagocytosis and intracellular killing of the homologous organism by either normal rabbit polymorphonuclear leukocytes or monocytes, when compared with normal rabbit serum. These immune sera did, however, show an increase in agglutinating and precipitating antibody level. Adsorption of normal human serum with some gram-positive and gram-negative bacteria, yeast, and some inert particles significantly reduced the phagocytosis-promoting factors of the serum. It would seem, then, that nonencapsulated S. aureus differs from other pathogenic bacteria in that the humoral antibacterial factors promoting its phagocytosis and intracellular killing are not significantly enhanced by infection or immunization.

Journal Article↗
PubMed1970

Cell Wall Component Which Affects the Ability of Serum to Promote Phagocytosis and Killing of Staphylococcus aureus.

The role of various cell wall components of nonencapsulated Staphylococcus aureus in phagocytosis and killing was studied. Adsorption of human serum with S. aureus cell walls, or trypsin-digested cell walls, reduced the rate of phagocytosis and killing of S. aureus by human-blood leukocytes when compared to unadsorbed serum. When the various components of the cell walls were used for adsorption, only the intact mucopeptide was found to remove these factors. Products of digestion of this mucopeptide with several enzymes were found to be inactive when used for adsorption of human serum. Other components tested were teichoic acids alpha, beta, and combinations of both and protein A. When used in equivalent amounts, these were found to have no effect on the removal of serum factors necessary for phagocytosis and intracellular killing of S. aureus.

Journal Article↗
PubMedDate not supplied

Bacteremia following dental extractions in patients with and without penicillin prophylaxis.

This study describes the type, rate and magnitude of bacteremia in 128 patients undergoing dental extractions with and without penicillin prophylaxis. The most prolonged and highest rates of bacteremia occurred in patients undergoing extractions and alveoplasty while under general anesthesia following nasotracheal intubation. The most common aerobes in patients receiving no penicillin were streptococci. Bacteroides sp. were detected most often in patients receiving penicillin prophylaxis. The overall bacteremia, streptococcal and polymicrobial bacteremia rates were lowest for the patients receiving penicillin. Only two of 66 patients given penicillin prophylaxis had recoverable streptococci in blood cultures. Our study indicates that both intravenous and oral penicillin G prophylaxis for dental extractions decreased bacteremia rates significantly, including the recovery of streptococci.

Alveoloplasty↗