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Biomedical subjects

L B Guze

Publications and source records attributed to L B Guze.

At least 163 records · Page 9Linked to original sources
PubMed1973

Defects in prodigiosin formation by L-forms of Serratia marcescens.

An L-form of Serratia marcescens has previously been shown incapable of producing the red pigment, prodigiosin, characteristic of the parent bacteria. Mutants of S. marcesens, unable to form one or the other of the two prodigiosin precursors, 4-methoxy-2,2'-bipyrrole-5-carboxaldehyde or 2-methyl-3-n-amylpyrrole, were used to test the nature of the L-form defect. The L-forms failed to form sufficient amounts of either precursor to be detected by the appropriate mutant, and, when furnished the precursors, failed to couple them to form prodigiosin.

Cell Count↗
PubMed1972

Susceptibility of herpesviruses to cytosine arabinoside: standardization of susceptibility test procedure and relative resistance of herpes simplex type 2 strains.

Susceptibility testing of herpes simplex type 1 (HSV-1) and type 2 (HSV-2) viruses to cytosine arabinoside (Ara-C) has been standardized under conditions of optimal reproducibility, susceptibility, and simplicity. Standard conditions were defined as virus inoculum of 10(1.5) to 10(2.5) TCID(50), WI-38 strain of lung fibroblasts, 2-day incubation, and observation of virus cytopathic effect after staining by the May-Greenwald-Giemsa method. The variability of minimum inhibitory concentration (MIC) of cytopathic effect was fourfold within each test and sixfold in successive assays. MIC values of all seven tested HSV-1 strains were in the range of 0.25 to 0.75 mug per ml, whereas four of nine HSV-2 strains had MIC values of 0.9 mug per ml and greater. A similar method can be used for assay of virus inhibitory titers of body fluids.

Cells, Cultured↗
PubMed1972

Activity of methacycline, related tetracyclines, and other antibiotics against various L-forms and their parent bacteria in vitro.

The activity of methacycline against microbial L-forms and their parent bacteria was compared with that of oxytetracycline, chlortetracycline, tetracycline, and demethylchlortetracycline, as well as with that of 22 other antibiotics which included examples of major groups of antibiotics. The L-forms and bacteria used were Streptococcus faecalis, S. faecium, S. faecalis var. zymogenes, Staphylococcus aureus (three strains), Proteus mirabilis (two strains), Pseudomonas aeruginosa, Escherichia coli (two strains), Sarcina flava, Serratia marcescens, and Klebsiella pneumoniae. The five tetracyclines had similar activities and were more active against L-forms than bacterial forms, except that the bacterial form of S. flava was more susceptible than the L-form. In general, other antibiotics (except the penicillins) were more active against L-forms than bacterial forms. There were certain exceptions where the bacterial form was more susceptible than the L-form. These included the effect of polymyxin B and colistin on P. aeruginosa, E. coli, and P. mirabilis, and the effect of gentamicin on P. aeruginosa, E. coli, S. flava, and S. marcescens.

Anti-Bacterial Agents↗
PubMed1972

Phagocytosis of microbial L-forms.

Little data are available regarding L-form phagocyte interactions. Due to difficulty with more conventional methods, a serum-free technique of surface phagocytosis employing cellulose ester micropore filters, fluorochrome staining, and reflecting fluorescence microscopy was developed. Intracellular localization of L-frms was confirmed by electron microscopy. In timed experiments, phagocytosis of a group D Streptococcus (ATCC 23241) and its L-form (T53I) were maximal at 30 min, although the bacteria were consistently better phagocyted. Phagocytosis of an Escherichia coli (strain Yale) and its L-form was also demonstrated with the same technique. The lesser phagocytosis of L-forms may be related to their lower chemotactic activity.

Enterococcus faecalis↗
PubMed1972

Pyelonephritis. XIV. Effect of immunization on experimental Escherichia coli pyelonephritis.

Mice immunized subcutaneously with heat-killed Escherichia coli were protected from pyelonephritis produced by the intravenous route, but there was little or no protection from ascending infection. No significant protection from ascending or hematogenous pyelonephritis was demonstrated when immunization was accomplished by injecting heat-killed E. coli into the bladder. Heat-killed E. coli injected either subcutaneously or into the bladder protected mice from early endotoxic death after intravenous or bladder challenge.

Adjuvants, Immunologic↗
PubMed1972

Osmotic stability and sodium and potassium content of L-forms of Streptococcus faecalis.

A stable L-form of Streptococcus faecalis (T(53)) was transferred in media containing decreasing concentrations of sucrose until it grew in medium without added osmotic stabilizer. This L-form (designated T(53I)) was compared with T(53) from which it was derived. The survival of these two L-forms suspended at different osmolalities showed that maximal survival for T(53I) was 350 to 400 milliosmolal and for T(53) was 900 to 1,000 milliosmolal. Both peaks were at the osmolality of their growth media. Measurement of intracellular potassium and sodium showed that the concentration of these ions was reduced in T(53I).

Cell Survival↗
PubMed1972

Human diseases associated with mycoplasms. With an appendix on simple culture techniques.

The mycoplasmas (formerly called pleuropneumonia-like organisms, or pplo) are a group of pleomorphic micro-organisms characterized by lack of cell wall and ability to form colonies on agar resembling tiny fried eggs. They have been recognized as pathogens of lower mammals since 1898. Of the more than 40 known veterinary species, many are pathogens, commonly causing pneumonia, arthritis or arteritis. Of the mycoplasmas found in man, Mycoplasma pneumoniae is the only well established human pathogen. It is responsible for a variety of respiratory syndromes, of which the most frequently recognized is cold agglutinin-positive atypical pneumonia. Hematologic, neurologic and dermatologic complications of this infection have been noted. M. hominis has been implicated as a causative factor in various febrile complications of pregnancy, such as septic abortion and amnionitis. T-strain mycoplasmas are ubiquitous in the human genitourinary tract, but attempts to link their presence to disease have thus far been unsuccessful. Mycoplasmas also have been associated with neoplastic disease and with rheumatoid arthritis. The validity of these latter findings is unclear, and additional study is needed.

Agglutinins↗