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Biomedical subjects

J S Baker

Publications and source records attributed to J S Baker.

31 records · Page 2Linked to original sources
PubMed1984

Comparison of various methods for differentiation of staphylococci and micrococci.

A modified oxidase test (Remel, Lenexa, Kans.) and susceptibility to furazolidone and lysostaphin (Remel) were evaluated in conjunction with the Staph-Ident strip (Analytab Products, Plainview, N.Y.) to accurately differentiate between staphylococci and micrococci. A total of 414 clinical isolates of catalase-positive, gram-positive cocci were each tested with the Staph-Ident strip and by glucose fermentation, acid production from glycerol, susceptibility to furazolidone and lysostaphin, and the oxidase test. Based on the reference methods of glucose fermentation and acid production from glycerol, 396 (95.6%) of the organisms were classified as Staphylococcus species and 18 (4.4%) were classified as Micrococcus species. Of the staphylococci, 99% were oxidase negative and susceptible to furazolidone; 82% were susceptible to lysostaphin. All of the micrococci were oxidase-positive and resistant to furazolidone and lysostaphin. Of the staphylococci, 99% were identified to species by the Staph-Ident strip. However, six (33%) of the micrococci were incorrectly identified as Staphylococcus species (three each of Staphylococcus hominis and Staphylococcus saprophyticus). Because of the demonstrated sensitivity and specificity of the oxidase and furazolidone susceptibility tests, it is suggested that either of these methods be used in the clinical laboratory to accurately differentiate between staphylococci and micrococci. It is also suggested that when working with the Staph-Ident strip, additional testing such as furazolidone susceptibility or oxidase activity should be performed to provide increased accuracy in the differentiation and characterization of members of the family Micrococcaceae.

Bacteriological Techniques↗
PubMed1983

Particle size distribution analysis as a rapid method to detect significant bacteriuria.

Particle size distribution analysis (PSDA) was evaluated as a rapid screening method for detecting significant bacteriuria by linking a C1000 Channelyzer to a Coulter Counter. Colony counts and PSDA screening results were compared for 800 urine specimens. The PSDA method proved to be 92% specific, but only 64% sensitive, for detecting at least 10(5) colony forming units (CFU)/ml. By performing serial dilution colony counts on 109 culture-positive specimens (greater than or equal to 10(5) CFU/ml), it was determined that the low level of sensitivity (64%) was due to culture-positive specimens that had between 10(5) and less than 10(7) CFU/ml. The sensitivity of the PSDA method increased to 90% and 100% when culture-positive specimens had 10(7) or more and 10(8) or more CFU/ml, respectively. The low level of sensitivity demonstrated in this investigation makes the introduction of this method into clinical usage unacceptable at this time.

Bacteriuria↗
PubMed1980

In vitro antagonism by erythromycin of the bactericidal action of antimicrobial agents against common respiratory pathogens.

Ten strains each of Staphylococcus aureus, Haemophilus influenzae, Enterobacter spp., Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, and Streptococcus pneumoniae were tested in vitro against erythromycin combined with ampicillin, cefamandole, or gentamicin. Antagonism by erythromycin occurred with 47% of the combinations involving strains of S. aureus and to a lesser degree with H. influenzae. Synergy occurred most commonly with H. influenzae (27%). The high frequency of antagonism and synergy with these organisms was associated with a broad range of bacteriostatic action by erythromycin against these same bacteria. The implications for the treatment of pneumonia are discussed.

Ampicillin↗
PubMed1979

The eye blink as a time-locked response: implications for serial and second-order conditioning.

A series of experiments were conducted to determine what factors control responding to the first element of a two-element serial compound in rabbit eyelid conditioning. An examination of response topography indicated that the eye-blink CR is rigidly timed to occur when the US is expected. This response-system characteristic prevents the occurrence of a CR during the first element of a serial compound or during the second-order CS in second-order conditioning. The comparison of a serial gap procedure with conventional serial and trace conditioning procedures suggested that the associative strength of the first element of a serial CS is not strongly influenced by either a second-order conditioning process or by the variable-reinforcement principle.

Animals↗
PubMedDate not supplied

Changes in blood markers of serotoninergic activity following high intensity cycle ergometer exercise.

The purpose of this study was to measure concentrations of adrenaline (A), noradrenaline (NE), free tryptophan (f-Trp), prolactin (PRL), nonesterified fatty acids (NEFA), and blood lactate following 30 s of high-intensity cycle ergometer exercise. Adrenaline (A) and NE concentrations increased immediately postexercise (P < 0.05) and returned to levels observed at baseline 24 h later. Plasma f-Trp concentration decreased by 23.5% immediately following exercise (P < 0.05). There were no changes observed in serum concentrations of PRL. Plasma NEFA concentrations decreased immediately following exercise by 46% (P < 0.05) and returned to baseline values 24 h later. Whole blood lactate concentrations increased immediately post exercise (P < 0.05), and were higher than those measured 24 h later (P < 0.05). These findings indicate that blood markers of serotoninergic activity were unaltered by a single 30 s bout of maximal cycling.

Adult↗