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Biomedical subjects

P Bonin

Publications and source records attributed to P Bonin.

At least 37 records · Page 2Linked to original sources
PubMed1989

Salt requirements in the denitrifying bacterium Pseudomonas nautica 617.

Pseudomonas nautica 617, which was isolated from superficial marine sediment, was found to require sodium for growth. Growth also appeared to be sensitive to the divalent cation, Mg2+, the presence of which, together with that of Na+, was necessary for achieving maximal growth. We investigated cell capacity to resist lysis after washing with either 0.05 M MgCl2 or 0.5 M NaCl, by monitoring suspension optical density changes as well as the release of ultraviolet absorbing material. Mg2+ turned out to play a significant role in stabilizing the structure of the cell envelope. Respiratory activity was also sensitive to ionic environment. With cells washed with 0.05 M MgCl2 and suspended in 0.05 M Tris buffer, the respiration rate, assessed by N2O evolution, was 15% of that measured in artificial sea water. Upon addition of 0.5 M Na+, nitrous oxide production rose to 32% of the reference level. The dinitrification rate was fully restored by further addition of 0.05 M Mg2+. K+ alone had almost no effect, but when added with Na+, the rate of denitrification increased to 45%.

Bacteriolysis↗
PubMed1986

Exonuclease activity associated with a multiprotein form of HeLa cell DNA polymerase alpha. Purification and properties of the exonuclease.

The DNase that is associated with a multiprotein form of HeLa cell DNA polymerase alpha (polymerase alpha 2) has two distinct exonuclease activities: the major activity initiates hydrolysis from the 3' terminus and the other from the 5' terminus of single-stranded DNA. The two exonuclease activities show identical rates of thermal inactivation and coincidental migration during chromatofocusing, glycerol gradient centrifugation, and nondenaturing polyacrylamide gel electrophoresis of the DNase. Moreover, the purified DNase shows a single protein band of Mr 69,000 following nondenaturing polyacrylamide and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The 3'----5' exonuclease activity hydrolyzes only single-stranded DNA substrates and the products are 5' mononucleotides. This activity recognizes and excizes mismatched bases at the 3' terminus of double-stranded DNA substrates. The 3'----5' exonuclease does not hydrolyze 3' phosphoryl terminated single-stranded DNA substrates. The 5'----3' exonuclease activity also only hydrolyzes single-stranded DNA substrates. The rate of hydrolysis, however is only about 1/25th the rate of the 3'----5' exonuclease. This exonuclease activity requires a 5' single-stranded terminus in order to initiate hydrolysis and does not proceed into double-stranded regions. The products of hydrolysis by 5'----3' exonuclease are also 5' nucleoside monophosphates.

Centrifugation, Density Gradient↗
PubMed1985

Carbamazepine and carbamazepine-10,11-epoxide serum concentrations in epileptic children.

Carbamazepine (CBZ) and carbamazepine-10,11-epoxide (CBZ-epox) steady-state serum concentrations were measured in 82 children who had generalized tonic-clonic, or partial seizures. There was no correlation between a given dose and serum concentrations, whether other anticonvulsant drugs were used or not. Epileptic children receiving polytherapy (CBZ associated with one or more of the following drugs: phenobarbital, primidone, phenytoin, ethosuximide) had significantly different CBZ clearance values and percent CBZ-epox than did patients given CBZ alone. Even though given lower doses, girls had higher CBZ concentrations and lower CBZ clearance values than did boys. Older girls had lower serum concentrations of CBZ-epox than did younger girls. Seizure-free children had higher CBZ serum levels and lower CBZ clearance values than did those with uncontrolled seizures. The percentage of CBZ-epox in children with uncontrolled seizures was significantly higher than in children without seizures. These data indicate that serum levels of CBZ and CBZ-epox correlate more with factors such as associated drugs, age, and sex than with administered dose. Therefore, CBZ serum level monitoring represents an essential means of individualization of anticonvulsant drug therapy.

Adolescent↗
PubMed1985

Antigens of Treponema pallidum recognized by IgG and IgM antibodies during syphilis in humans.

IgG and IgM antibody specificities for antigens of Treponema pallidum Nichols strain were determined by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the western blot technique in sera from patients with untreated syphilis, normal persons, persons with biologic false-positive tests for syphilis, and sexual contacts of persons with infectious syphilis. IgG reactivities of sera from individuals with primary syphilis varied considerably but consistently exhibited strong reactivity to a 48-kilodalton band. Sera from patients with secondary and early latent syphilis uniformly demonstrated reactivity to 22 separate polypeptide antigens; decreased reactivity was seen in late latent syphilis. Normal and biologic false-positive sera showed weak IgG reactivity against none to 12 polypeptides. Sera from asymptomatic contacts of persons with infectious syphilis showed reactivity to a varying number of treponemal antigens, including some reactions not seen with normal sera. IgM reactivity was most prominent in secondary syphilis but was demonstrable at all stages of disease.

Antibodies, Bacterial↗
PubMed1984

Isolation of Neisseria gonorrhoeae on selective and nonselective media in a sexually transmitted disease clinic.

To assess the practical significance of reported increases in the prevalence of vancomycin-susceptible strains of Neisseria gonorrhoeae on isolation of this organism, antibiotic-free chocolate agar (CA), modified Thayer-Martin medium (MTM), and a vancomycin-free selective medium (VFSM) were compared in a sexually transmitted disease clinic. Among 326 cervical gonococcal infections detected in a comparison of CA with MTM, 92.0% were detected on CA, compared with 98.2% on MTM (P less than 0.001). Similarly, among 306 cervical infections detected in a comparison of MTM and VFSM, 95.8% of infections were detected with VFSM, compared with 98.4% for MTM (P = 0.10). For 1,632 urethral infections in men, all three media were equivalent, with none detecting fewer than 98% of the infections. Compared with a single inoculation, dual inoculation of MTM increased the diagnostic yield by 1.5% for 206 urethral infections and 2.4% for 83 cervical infections. In our clinic population, MTM is superior to CA or VFSM for the diagnosis of genital gonococcal infections, especially in women. The increased yield that accrued from inoculation of both MTM and either of the other media was not sufficiently high to warrant routine use of this practice in our clinic.

Agar↗
PubMed1984

Antigen detection for the diagnosis of gonorrhea.

We compared the diagnostic value of an enzyme immunoassay method for detection of gonococcal antigen in genital secretions with culture results and direct Gram stain for Neisseria gonorrhoeae in 1,171 men and 723 women attending a sexually transmitted disease clinic. When compared with culture results in men, the immunoassay provided a sensitivity of 94% and a specificity of 98% and was essentially equivalent to the urethral Gram stain. The predictive value of a positive immunoassay was 97% in men with a urethral discharge in whom the prevalence of gonorrhea was 36%, and 30% in men without urethral discharge, who had a 2% prevalence of gonorrhea (P less than 0.001). The sensitivity of the immunoassay was 95% in men with and 67% in men without urethral discharge (P less than 0.01). In women, the immunoassay resulted in a sensitivity of 78% and a specificity of 98% compared with cervical culture and had a significantly better sensitivity than the cervical Gram stain (78 versus 48%, P less than 0.001). Analysis of patients with discrepant culture and immunoassay results suggested that most culture-negative, immunoassay-positive patients probably did not have gonorrhea. After treatment, all but 1 of 59 originally culture- and immunoassay-positive patients became negative in both tests by 3 days. Results of the immunoassay were not affected by transport or by refrigeration for up to 30 days.

Antigens, Bacterial↗
PubMed1984

[Value of rifampin in the treatment of staphylococcal septicemia].

Analysis of 20 cases of staphylococcal septicemia, observed over 1 1/2 months in a general hospital, confirms that these infections are frequent and severe. They occurred in compromised hosts and were nosocomial infections in 2/3 of cases. An intravenous device (particularly a central venous catheter) was associated with 70% of staphylococcal septicemia. Study of bacterial susceptibility to antibiotics and clinical course leads to advocate that high risk patients with fever be initially given rifampin combined with netilmicin.

Adolescent↗
PubMed1983

Resolution of the diadenosine 5',5"'-P1,P4-tetraphosphate binding subunit from a multiprotein form of HeLa cell DNA polymerase alpha.

A diadenosine 5',5"'-P1,P4-tetraphosphate (Ap4A) binding subunit has been resolved from a high molecular weight (640,000) multiprotein form of DNA polymerase alpha [deoxynucleoside triphosphate:DNA nucleotidyltransferase (DNA-directed), EC 2.7.7.7] from HeLa cells [DNA polymerase alpha 2 of Lamothe, P., Baril, B., Chi, A., Lee, L. & Baril, E. (1981) Proc. Natl. Acad. Sci. USA 78, 4723-4727]. The Ap4A binding activity copurifies with the DNA polymerizing activity during the course of purification. Hydrophobic chromatography on butylagarose resolves the Ap4A binding activity from the DNA polymerase. The Ap4A binding activity is protein in nature since the binding of Ap4A is abolished by treatment of the isolated binding activity with proteinase K but is insensitive to treatment with DNase or RNase. The molecular weight of the Ap4A binding protein, as determined by polyacrylamide gel electrophoresis under nondenaturing conditions or by NaDodSO4/polyacrylamide gel electrophoresis after photoaffinity labeling of the protein with [32P]Ap4A is 92,000 or 47,000. The binding activity of this protein is highly specific for Ap4A.

Adenine Nucleotides↗
PubMed1983

Frequency of beta-lactamases that are markedly active against carbenicillin in the Pseudomonas aeruginosa strains isolated in a medical school hospital.

During one year, 71 carbenicillin-resistant Pseudomonas aeruginosa strains were isolated. The detection of the beta-lactamase activity in these strains was performed by the iodometric method. The beta-lactamases were found in 70% of the carbenicillin-resistant strains and were characterized by isoelectric focusing and by determination of substrate profiles. Seventy-two per cent of the beta-lactamases tested focused in the same way as the PSE-1 type from strain PU21(RPL11). The determination of the substrate profiles by the acidimetric method showed that these enzymes had a high activity towards carbenicillin and that they can vary in their hydrolysis of cephalosporins. Such PSE-1 type beta-lactamases were found in gentamicin-tobramycin-resistant strains whereas other types of enzymes (PSE-4 enzymes and enzymes with pI 7.7) were found in strains sensitive to these antibiotics.

Carbenicillin↗
PubMed1977

Rubella in Seattle-King County Washington.

Assessment of the results of rubella hemagglutination-inhibition tests from women of child-bearing age in Seattle-King County suggests no community susceptibility problem except among women age 19 in 1976. Within this cohort 23 per cent were susceptible, probably because these women were too young to experience a full exposure to natural rubella prior to introduction of rubella vaccine and too old to be immunized against rubella in the elementary schools in 1970. Follow-up of women under age 25 who were seronegative for rubella antibody indicated that one-third subsequently received rubella vaccine.

Adolescent↗
PubMed1976

Seattle-King County revisited.

For approximately five years the Seattle-King County Public Health Laboratory has measured its diagnostic laboratory workload quantitatively in terms of relative values. Seattle-King County has used the laboratory average cost-per-relative value concept. However, increasing operational costs, multiple demands for the same tax dollar, and professional desire for more precise costing information led the laboratory staff to refine their method of determining a cost-per-relative value. This article shares their new methodology of determining a cost-per-relative value for each primary cost center. Also shared are a few examples of how costs differ when using the old method in comparison to using the new method.

Costs and Cost Analysis↗