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Biomedical subjects

P L Sandok

Publications and source records attributed to P L Sandok.

11 recordsLinked to original sources
PubMed1978

Unsustained multiplication of treponema pallidum (nichols virulent strain) in vitro in the presence of oxygen.

Treponema pallidum (Nichols virulent strain) was incubated with or without oxygen using a modified medium supplemented with reduced glutathione and a variety of nutrients (PRNF10-B). Two- to fourfold increases in treponemal numbers were observed in cultures without mammalian cells within 96 h of incubation under 5 to 6% oxygen. Treponemal motility and multiplication were maintained more satisfactorily in cultures that were diluted and transferred daily, using an equal volume of fresh medium. Treponemes incubated without oxygen did not significantly increase in number. Virulent microorganisms were detected for at least 96 h in the cell-free system. In the presence of 3 to 4% oxygen, two- to fivefold increases in treponemal numbers were observed in the supernatant fluids of cultures containing human prepuce cells after 48 to 120 h at 35 degrees C. Without oxygen, treponemal numbers rarely approached a threefold increase. Virulent treponemes were detected by the rabbit skin lesion test after at least 120 h in vitro. Regardless of the system of incubation, increases in treponemal numbers could not be sustained for longer than 120 h, and treponemal virulence decreased as a function of time in vitro.

Animals↗
PubMed1978

Effects of fatty acids on motility retention by Treponema pallidum in vitro.

Treponema pallidum (Nichols virulent strain) was incubated under 75% N2 + 20% H2 + 5% CO2 in prereduced serum-free modified Eagle-Richter medium supplemented with different concentrations of various long-chain fatty acids complexed with fatty acid-free bovine serum albumin. Motility retention was greater in medium with oleic acid containing 15 rather than 2 mg of albumin per ml. Palmitic, stearic, oleic, or linoleic acid alone caused rapid loss of motility at concentrations as low as 5 microgram/ml. Elaidic acid (92 microgram/ml) alone had no effect on motility. Various combinations of saturated plus unsaturated fatty acids did not inhibit motility retention or were less inhibitory than either of the individual fatty acid components. The combination of palmitic plus oleic acids was least toxic. Rapid loss of motility occurred with pairs of unsaturated or saturated fatty acids, or with Tween 40, 60, or 80, alone or combined. Autoxidation of oleic acid resulted in decreased toxicity for T. pallidum but increased toxicity for baby hamster kidney cells.

Culture Media↗
PubMed1978

Murine macrophage-lymphocyte interactions: scanning electron microscopic study.

Light and scanning electron microscopic observations revealed murine macrophage-lymphocyte interactions involving the initial contact of peritoneal, spleen, or thymus lymphocytes with peritoneal macrophage processes or microprocesses followed by clustering of lymphocytes over the central nuclear area of the macrophages. Lymphocyte-lymphocyte clustering was not observed in the absence of macrophages. Attachment and subsequent clustering appeared not to require the presence of serum or antigen; the attachment of allogeneic or xenogeneic lymphocytes was comparable to that seen in the syngeneic system, but central clustering of these lymphocytes failed to occur. No attachment or clustering was observed when thymic lymphocytes were cultured with thymus derived fibroblasts rather than with peritoneal macrophages. Lymphocyte attachment to immune, antigen-activated, syngeneic macrophages occurred more rapidly than that to normal unstimulated syngeneic macrophages; however, lymphocytes attached to the "activated" macrophages appeared to be killed by a nonphagocytic mechanism. A similar increase in the rate of lymphocyte attachment to macrophages occurred in the presence of migration inhibitory factor. Subsequent lymphocyte clustering on macrophages was observed in the migration inhibitory factor-stimulated cultures. In addition, lymphocyte-macrophage interactions similar to those in vitro were observed to occur in vivo on intraperitoneally implanted cover slips.

Animals↗
PubMed1978

Radiolabeling of Treponema pallidum (Nichols virulent strain) in vitro with precursors for protein and RNA biosynthesis.

We observed uptake of [U-14C]serine, U-14C-labeled amino acid hydrolysates, and [2-14C]uracil by virulent Treponema pallidum in vitro for at least 96 h. No uptake of [2-14C]thymine, [1-14C]pyruvate, [U-14C]pyruvate, and [2-14C]uridine was detected. Treponemal protein and RNA biosynthetic activity was identified by erythromycin inhibition of amino acid and uracil uptake. Radioactivity due to uptake of radiolabeled amino acids by residual testicular cells in the cultures remained at background levels regardless of the presence or absence of cycloheximide. Accumulation of the radiolabeled substrates by T. pallidum proceeded at a linear rate for 48 to 96 h during incubation in vitro. The longevity of substrate uptake using the system of incubation described will facilitate future studies on the metabolism of the microorganism to help determine essential growth factors and environmental conditions for multiplication of T. pallidum in vitro.

Amino Acids↗
PubMed1976

Examination of various cell culture techniques for co-incubation of virulent Treponema pallidum (Nichols I strain) under anaerobic conditions.

Treponema pallidum (Nichols virulent) was incubated with and without cells in cell culture medium reduced to -275 mV Ecal, pH 7.3, under deoxygenated conditions. Five to ten percent of the treponemes attached to cells and remained motile for at least 120 h in cell-treponeme systems of co-incubation. Virulent treponemes could be detected after 120 to 144 h in the supernatant fluids of cell-treponeme co-incubation cultures and in cell-free tubes containing medium harvested from aerobically cultivated mammalian cells. Medium supplemented with ox serum ultrafiltrate, pyruvate, and sodium thioglycolate and gas mixtures containing H2 and CO2 enhanced treponemal survival. Increases in treponemal numbers were observed using dark-field microscopy but were not substantiated using the rabbit lesion test. Continuous passage of the treponeme was not achieved in vitro.

Anaerobiosis↗
PubMed1975

Alterations in mouse macrophage migration: a function of assay systems, lymphocyte activation product preparation, and fractionation.

Supernatants from mouse spleen cell and peritoneal cell cultures were tested for the presence of lymphocyte activation products. Supernatants from mouse spleen cell and peritoneal cell cultures incubated with brucella antigens contained a macrophage migration inhibition factor(s) and a macrophage spreading factor(s) only if the cells were harvested from Brucella-infected mice. After dialysis and freeze-drying, the supernatants were fractionated by preparative acrylamide-gel electrophoresis. Three fractions with lymphocyte activation product activity were obtained from the fractionated supernatants of mouse spleen cells and peritoneal cells harvested from Brucella-infected mice and cultured with brucella antigen. One fraction inhibited mouse macrophage migration from capillary tubes but not from agarose wells. A second fraction not only inhibited macrophage migration from both agarose wells and capillary tubes, but also contained an activity(s) that stimulated macrophage migration through Nuclepore filters and induced macrophage spreading. A third fraction timulated macrophage migration from agarose wells and also contained an activity(s) that stimulated macrophage migration through Nuclepore filters. Fractionated supernatants of mouse spleen cells and peritoneal cells harvested from uninfected mice incubated with and without brucella antigen, as well as of cells harvested from infected mice and not incubated with antigen, did not contain detectable lymphocyte activation products.

Antigens, Bacterial↗
PubMed1975

Retention of motility and virulence of Treponema pallidum (Nichols strain) in vitro.

A maintenance medium for Treponema pallidum was designed to hold its Eh at the optimum for that organism, -10 to -110 mV. After 100% motile (freshly harvested) T. pallidum was inoculated into the medium, the motility of the treponemes decreased to 80% after 2 days, 50% after 3.5 days, and 0% after 9 days during incubation at 34 C. Full virulence was retained for 2 days, but it dropped rapidly thereafter, and the treponemes became avirulent by day 5.

Animals↗
PubMed1974

Isolation of substances responsible for lymphokine activity from sensitized mouse spleen cells.

Cultures of brucella-sensitized mouse spleen cells exposed to Brucella abortus antigens in vitro release macrophage migration inhibition factor (MIF) and macrophage spreading factor. Subjecting the supernatants from such cultures to preparative scale electrophoresis in acrylamide gel yields several fractions, one of which contains both MIF and macrophage spreading factor. This material has properties attributable to guinea pig MIF: it is nondialyzable, heat stable, nontoxic to macrophages from heterologous murine donors, and has a greater anodal electrophoretic mobility than guinea pig serum albumin. Another fraction from the gel column inhibits macrophage spreading; its electrophoretic mobility is similar to that of guinea pig gamma globulin. Neither brucella antigen nor skin reactive substances were detectable in any acrylamide gel column fraction when tested by the mouse footpad induration assay technique.

Animals↗