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J L Ryan

Publications and source records attributed to J L Ryan.

99 records · Page 6Linked to original sources
PubMed1969

Partial purification of native rRNA and tRNA cistrons from mycoplasma sp. (Kid).

Precise optical melting profiles of purified DNA from Mycoplasma sp. (Kid) show a secondary hyperchromic rise, corresponding to 1.4 per cent of the total DNA, occurring at 88 degrees C, while the bulk of the DNA melts at 79.5 degrees C, indicating an average base composition of 24.9 per cent guanine-cytosine (G-C). A method is presented, using sonication followed by hydroxyapatite column chromatography, for the partial purification of regions of a genome which contain significantly higher G-C than the average value for the genome. The procedure does not involve denaturation and renaturation of the high G-C material so that purified DNA is in its native, double-stranded state and has a normal melting profile. When applied to Mycoplasma sp. (Kid), the method yielded a fraction of native DNA enriched 40 times with respect to those regions coding for rRNA and tRNA. This enriched DNA has a saturation hybridization value of 15.9 per cent with Kid rRNA plus tRNA. The saturation hybridization values of the bulk DNA with rRNA and tRNA are 0.26 per cent and 0.16 per cent, respectively. Based on a genome size of 6.84 x 10(8), obtained by electron microscopy, this indicates that Mycoplasma sp. (Kid) contains only enough ribosomal DNA to code for one set of 23S plus 16S rRNA and only enough DNA complementary to tRNA to code for 44 different tRNA molecules.

Chromatography, Ion Exchange↗
PubMedDate not supplied

Hyperbaric oxygen therapy for acute ankle sprains.

We conducted a randomized double-blind study of 32 subject with acute ankle sprains to compare treatment with hyperbaric oxygen at 2 atmospheres absolute pressure (N = 16) (treatment group) with treatment with air at 1.1 atmosphere absolute pressure (N = 16) (control group) in a hyperbaric chamber. Each group received three treatments at their respective pressures: one for 90 minutes and two for 60 minutes each. Mean age, severity grade, and time to treatment (treatment group, 34.3 +/- 6.3 hours; control group, 32.6 +/- 4.6 hours) were similar in both groups. Joint function measured by a functional index improved from 0.40 +/- 0.2 to 6.3 +/- 0.4 with hyperbaric oxygen and from 0.8 +/- 0.3 to 5.3 +/- 0.6 with air. The change from initial to final evaluation was significantly greater in the treatment group. Foot and ankle volume by water displacement decreased from 1451 +/- 57 ml to 1425 +/- 63 ml with hyperbaric oxygen and from 1403 +/- 50 ml of 1371 +/- 45 ml with air (no difference was noted between hyperbaric oxygen treatment and air treatment using a two-day analysis of variance). Subjective pain index fell from 3.3 +/- 0.5 to 0.8 +/- 0.3 with hyperbaric oxygen and from 2.6 +/- 0.3 to 0.3 +/- 0.2 with air. No differences were noted in passive or active range of motion when comparing hyperbaric oxygen treatment with air treatment. Time to recovery was the same in both groups (treatment, 16.0 +/- 6.3 days; control, 15.4 +/- 2.8 days). Regression analysis to determine the influence of time to treatment, initial severity of injury, hyperbaric oxygen, and age showed no effect of hyperbaric oxygen treatment on time to recovery.

Acute Disease↗
PubMedDate not supplied

Subcutaneous epinephrine vs. nebulized metaproterenol in acute asthma.

The efficacy and side effects of subcutaneous epinephrine (E) and aerosolized metaproterenol (M) were compared in acute asthma. Adults randomly received E 0.3 mg sub-Q q20min (max 0.9 mg; n = 20) or M 15 mg in 3.0 ml NaCl 0.9% nebulized over 10 minutes (n = 20) in a double-blind fashion. Vital signs and peak expiratory flow rate (PEFR) were measured every ten minutes for one hour. The two groups were comparable in age, weight, baseline theophylline concentration, PEFR, heart rate, and systolic and diastolic blood pressure. PEFR improved in both groups within ten minutes (p less than 0.01; analysis of variance). There was no difference in PEFR between the groups over the one-hour observation period following treatment. Heart rate decreased following treatment in M patients (p less than 0.05), but remained unchanged in E patients. Systolic blood pressure rose slightly in E patients (p less than 0.01), but remained unchanged in M patients. Subcutaneous E and nebulized M are equally effective as initial therapy in acute asthma.

Acute Disease↗
PubMedDate not supplied

Synergism of azlocillin, mezlocillin, piperacillin in combination with tobramycin against Klebsiella and Pseudomonas.

Fifty-three clinical isolates of Klebsiella and fifty-one clinical isolates of Pseudomonas aeruginosa, twenty-six of which were carbenicillin-(CARB) resistant, were tested for susceptibility to mezlocillin (MEZ), azlocillin (AZL), and piperacillin (PIP), both alone and in combination with tobramycin (TOB) using the microtiter broth diluent method and an inoculum density of 10(6) CFU/ml. The Klebsiella were highly resistant to TOB, MEZ, and PIP (MIC90: 8, greater than 256, greater than 128 micrograms/ml, respectively). Synergy was demonstrated in 53 percent (PIP/TOB) and 51 percent (MEZ/TOB). An indifferent response was observed in 47 percent (PIP/TOB) and 49 percent MEZ/TOB of the Klebsiella. PIP, MEZ, and AZL in combination with TOB showed synergism against CARB-resistant Pseudomonas in less than 10 percent of the strains tested. Synergy could be demonstrated against CARB-susceptible Pseudomonas with the combinations PIP/TOB, AZL/TOB, and MEZ/TOB in 12 percent, 12 percent, and 24 percent, respectively, of the twenty-five strains tested. Indifferent effects were observed in 84 percent, 88 percent, and 76 percent, respectively, of these same CARB-susceptible strains. These data suggest that there is no significant difference in the incidence of synergy with these new penicillins and tobramycin against either Pseudomonas or Klebsiella.

Azlocillin↗
PubMedDate not supplied

Changes in membrane gangliosides: differentiation of human and murine monocytic cells.

Membrane ganglioside changes in murine peritoneal macrophages and the human promyelocytic leukemia cell line HL-60 have been assessed by two-dimensional thin-layer chromatography. C3H/HeJ mice respond to protein-containing endotoxin but are hyporesponsive to protein-free endotoxin preparations. Compared to unstimulated resident cells, protein-containing endotoxin produced an alteration in the C3H/HeJ macrophage ganglioside pattern whereas protein-free endotoxin did not. In comparison, differentiation of HL-60 cells to a neutrophil-like cell by dimethylsulfoxide gave a ganglioside pattern similar to unstimulated HL-60 cells. However, differentiation of HL-60 cells by phorbol myristate acetate to macrophage-like cells results in a large increase in the monosialoganglioside GM3. The evidence presented indicates that discrete ganglioside changes occur in murine monocytes and HL-60 cells upon induction to cells with increased macrophage functions.

Animals↗
PubMedDate not supplied

Lack of specificity of brain gangliosides in the modulation of lymphocyte activation.

A potential role for glycolipid gangliosides to act as immunomodulating agents has been suggested. Most studies have employed brain gangliosides. We have systematically investigated highly purified murine brain gangliosides for their ability to modulate lymphocyte activation. All sialic acid classes of ganglioside inhibited lipopolysaccharide (LPS)-induced antibody secretion and all polysialated gangliosides inhibited LPS-induced DNA synthesis. Monosialated gangliosides had no effect on DNA synthesis induced by LPS. 8-BrcGMP-induced DNA synthesis was also inhibited, suggesting that a negative signal was delivered to B lymphocytes by co-cultivation with exogenous gangliosides. The lack of specificity with respect to sialic acid class observed in these studies suggests that further investigation of an immunomodulatory role for gangliosides focus on endogenous lymphocyte gangliosides.

Animals↗