Biomedical subjects

S Orr

Publications and source records attributed to S Orr.

32 records · Page 2Linked to original sources

PubMed1992

The effect of partial denture connectors on gingival health.

The effect on the gingiva of a variety of relationships of a removable partial denture connector to the gingival margin was investigated in 10 subjects. Acrylic resin baseplates were designed incorporating a variety of relationships of the connector to the gingival margin. The appliances were worn for a 12 hour period daily, for 21 days. At baseline and at days 7, 21 and 49, plaque index, gingival index and probing pocket depth measurements were recorded, and subgingival plaque samples were examined using darkfield microscopy. No increase in plaque accumulation was detected in any area at any time interval. There was a significant increase in gingival index at day 21 in areas where the appliance covered the gingival margin. Small increases in probing pocket depth were recorded at day 21, there being no difference between any of the test areas. Baseline values were re-established by day 49. No significant differences were detected in the percentage of motile organisms or spirochaetes counted in the subgingival plaque samples collected from any area. It was concluded that deterioration in gingival health occurred rapidly following the insertion of a removable appliance, and that coverage of the gingival margin, irrespective of the degree of gingival relief, had a detrimental effect.

Acrylic Resins↗

PubMed1990

Immune responses in humans while receiving adoptive immunotherapy with recombinant interleukin-2 and lymphokine-activated killer cells: acute anergy to mitogens and recall antigens.

In this study we evaluated the in vitro immunologic responses of 11 patients receiving immunotherapy with either interleukin-2 (IL-2, 3 X 10(6) units/m2) or IL-2 plus lymphokine-activated killer cells (LAK) over a 30-day period. Blastogenic responses to mitogens or recall antigens were found to significantly decrease during therapy. Pokeweed mitogen immunoglobulin (Ig) production decreased significantly in 7 patients or showed no change. In vivo skin tests for cell-mediated immunity were also performed and the average number of positive responses before IL-2/LAK therapy decreased to no positive responses (day 29 of therapy). Experiments were performed to determine whether decreased responses were a result of active suppression or a dilution effect by immature/mature cells that cannot respond to mitogen or antigen. Pre-therapy cells were mixed with fresh autologous (anergic) cells from day 29 of therapy in varying ratios. Blastogenesis and Ig production was measured. Our findings demonstrate that the decreased immune response observed during and after therapy is a result not of active immunosuppression but rather of a dilution effect by cells with immune dysfunction. We conclude that: (1) in vitro blastogenesis or Ig production tests using mitogens or antigens for patients undergoing IL-2 immunotherapy have no predictive value, and (2) the immune cells that are present are refractory.

Humans↗

PubMed1990

Immunologic effects of interleukin-2 adoptive immunotherapy in humans: acute in vitro anergy, in vivo antibody response to tetanus.

In a previous study we evaluated the in vitro immunologic responses of 14 patients receiving immunotherapy with either interleukin-2 (IL-2; 3 x 10(6) units/m2) or IL-2 plus lymphokine-activated killer (LAK) cells over a 45-day period. Blastogenic responses to mitogens or antigens were found to significantly decrease. Pokeweed mitogen immunoglobulin production decreased or showed no change. Multitest skin test response decreased during and after therapy. We concluded that, although natural killer and LAK activity are enhanced during therapy, in vitro blastogenic or immunoglobulin tests using mitogens or antigens for patients undergoing IL-2 immunotherapy have no predictive values and are depressed. In this study, we provide information that patients while receiving IL-2/interferon-alpha immunotherapy demonstrate as in the previous study in vitro reduced immunologic responses by at least 60%; however, in vivo, they had a normal immunoglobulin response to a tetanus booster. The disparity in results (in vitro versus in vivo) is unexplainable. Further analysis of other in vitro and/or in vivo tests is required to determine the effect IL-2 immunotherapy may have on the immune response status.

Antibodies, Bacterial↗

PubMed1987

Effects of variation of the tri-iodothyronine/reverse triiodothyronine ratio in vivo on the metabolic characteristics of subsequently isolated hepatocytes.

Reverse tri-iodothyronine (3,3',5'-tri-iodothyronine, rT3), a major product of the peripheral monodeiodination of thyroxine, was administered subcutaneously to fed rats at a dose of 100 micrograms/100 g body weight for 2 consecutive days. This dose induced a 17-fold increase in plasma rT3 (from 0.05 +/- SEM 0.01 to 0.85 +/- 0.11 ng/ml, P less than 0.001) whilst the plasma T3 concentration was decreased to half of the control value (0.40 +/- 0.03 to 0.20 +/- 0.02 ng/ml, P less than 0.01). As a result of these changes the T3/rT3 ratio was therefore decreased from 8.0 +/- 1.6 to 0.23 +/- 0.03 (P less than 0.001). Hepatocytes prepared from control or rT3-treated rats were incubated with [1-14C]oleate and the rates of 14CO2 release and glucose production were estimated. Despite the changes in ratio of T3 to rT3 observed in vivo, rates of 14CO2 release and glucose production rate from hepatocytes subsequently isolated were unchanged.

Animals↗

PubMed1983

Central cord syndrome.

Explore the source record for details and available documents.

Accidents, Traffic↗

PubMed1983

Cardiac valve surgery in patients with poor left ventricular function.

Of 316 patients who underwent operation for valvular heart disease at the Toronto Western Hospital, between January 1978 and December 1981, 41 (31 men, 10 women), ranging in age from 24 to 74 years, had severely impaired left ventricular function (ejection fraction less than 40% and left ventricular end-diastolic pressure more than 18 mm Hg). All 41 patients were in New York Heart Association (NYHA) class III or IV. Fourteen patients had disease of the aortic valve, 13 of the mitral valve and 14 of both aortic and mitral valves. Twenty-two patients also had serious coronary artery disease. The valve dysfunction was corrected in all patients by replacement or repair and all severe coronary artery stenoses were bypassed with saphenous vein grafts. There were three hospital deaths and five late deaths during a mean follow-up of 26 months (range from 6 to 48 months). All patients improved symptomatically by a least one functional NYHA class. The actuarial survival including operative deaths was 79%.

Adult↗

PubMed1982

Randomised trial of clomiphene citrate treatment and vitamin C for male infertility.

A prospective randomised trial was carried out to assess the effect of 6 months' treatment with either clomiphene citrate or vitamin C in 179 men complaining of infertile marriage. There was no significant difference in the wife's pregnancy rates between the 2 treatment groups. In order to detect a subgroup that might respond to clomiphene the results were analysed according to pre-treatment FSH and sperm density, with allowance being made for the result of the wife's tests, but still there was no significant difference in treatment response Vitamin C would seem a preferable and cheaper alternative treatment for male infertility.

Ascorbic Acid↗

PubMed1975

Radiation dose distributions and their optimization.

The current situation in the radiotherapy treatment of carcinoma of the larynx is discussed from a physicist's point of view and in the light of the results of one series of patients. The results suggest that the spatial distribution of dose obtainable with supervoltage irradiation for treatment of T1, to T4 No Mo cases is not far from the ideal, and that it is not difficult to prescribe an optimal distribution. A significant difference in the rate of local cure was found between those treated to a CRE value greater than 1,750 and those treated to less than 1,750. Gothenburg results supporting this finding are quoted. Methods are suggested of optimizing the dose distribution in time by increasing the effect on tumor cells without exceeding an acceptable tolerance to normal tissues.

Dose-Response Relationship, Radiation↗

PubMedDate not supplied

Kinetics of 2 genetically distinct Pneumocystis carinii populations in rat colonies.

The natural history of prototype and variant Pneumocystis carinii populations in several colonies of rats were monitored over time periods ranging from 1 to 4 years. Karyotypic profiles of organism populations from individual rats were evaluated for the proportion of prototype:variant P. carinii and the number of animals harboring co-infections were enumerated. Throughout the observation periods: (1) each P. carinii population retained its distinctive karyotype; (2) the proportions of prototype:variant within the lungs fluctuated; and (3) the number of rats co-infected within a colony varied. These surveys suggest a competition between 2 similarly adapted populations.

Animals↗

PubMedDate not supplied