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Biomedical subjects

D Lyons

Publications and source records attributed to D Lyons.

85 records · Page 5Linked to original sources
PubMed1987

Lymphokine-activated killer cell activity in rheumatoid arthritis.

The lymphokine-activated killer (LAK) cell activity in the peripheral blood of 23 patients with rheumatoid arthritis has been studied. Two control groups comprised (a) nine patients with another chronic inflammatory disease (sarcoidosis) and (b) 19 normal healthy volunteers. The LAK activity induced by human recombinant IL-2 was very similar in controls and patients with rheumatoid arthritis but was significantly decreased in patients with sarcoidosis, although the frequency of LAK-cell precursors measured using a limiting dilution assay was comparable in all three groups. The DNA synthetic response of peripheral blood mononuclear (PBM) cells to IL-2 was slightly decreased in patients with both rheumatoid arthritis and sarcoidosis as compared to controls, but this decrease was not statistically significant. Spontaneous DNA synthesis in PBM cells cultured in the absence of IL-2 was essentially identical in all three groups. We conclude on the basis of these results that the higher risk of non-Hodgkin's lymphomas in patients with rheumatoid arthritis cannot be attributed to an impairment of LAK activity. Furthermore, the doses of gamma-irradiation, which abolished the 'background' cytotoxicity of PBM cells cultured without IL-2 and also blocked effectively both spontaneous and exogenous IL-2-dependent DNA synthesis, had little effect on the generation of LAK activity. These observations are discussed in regard to the role of non-specific cytotoxic cells and the therapeutic efficacy of antiproliferative drugs in rheumatoid arthritis.

Adult↗
PubMed1987

Electrocardiographic changes with advancing age. A cross-sectional study of the association of age with QRS axis, duration and voltage.

In order to examine the electrocardiographic (ECG) changes which occur with advancing age we defined an apparently healthy reference population derived from prospectively followed subjects of the Framingham Heart Study. Healthy subjects were clinically free of hypertension, coronary artery disease, congestive heart failure and valve disease and were not taking antihypertensive or other cardiac medications. ECG tracings were analyzed by the IBM Bonner (V2) program. Mean values and correlations with age for PR duration, QRS duration and axis, S wave voltage V1 and R wave voltage V5 are presented. With advancing age in men there is a narrowing of QRS, a leftward QRS axis shift, and a loss of S V1 and R V5 amplitude. In women only a leftward QRS axis shift is associated with advancing age. These changes should be considered in defining normal age- and sex-specific reference values. These findings underscore theoretical limitations of commonly-used criteria for the ECG diagnosis of conditions such as left ventricular hypertrophy.

Adult↗
PubMed1986

Selective culture medium enhances survival of neuroblasts from postnatal rodent brain.

One of the major limitations to the study of the development of the nervous system in aneuploid mammalian embryos is that the aneuploid condition is usually lethal in utero. Liveborn aneuploid individuals often succumb rapidly because they have a constellation of malformations incompatible with postnatal survival. We have developed a selective tissue culture medium (D-val) which can be used with fetal calf serum or in a serum-free defined composition and which permits neuroblasts and glioblasts present in postnatal rodent (rat, mouse) brain to proliferate and differentiate in vitro. These cells contain D-amino acid oxidase, but fibroblasts do not. In this medium, fibroblasts cannot grow and are eliminated from the cultures without the use of deleterious compounds such as antimitotic or chemotherapeutic agents. With this medium, cultures containing neuroblasts can be established from normal rat and mouse brain as late as postnatal days 11-20. Cultures with significant numbers of proliferating cells can also be established from perinatal aneuploid mouse embryos, 'rescuing' the cells for further study.

Animals↗
PubMed1984

Bronchiolectasis caused by positive end-expiratory pressure.

Bronchiolectasis in patients with respiratory failure who are ventilated artificially with positive end-expiratory pressure (PEEP) appears to be associated with increased physiologic dead space. We found that the survival rate of 40 patients ventilated with PEEP was not significantly different from that of a control series of patients not receiving PEEP. Pulmonary function values, including the dead-space/tidal-volume ratio, returned to normal for the five PEEP patients in whom these variables were measured.

Adolescent↗
PubMed1977

Surgery and anesthesia in Ontario.

Operative and case-fatality rates in Ontario for eight elective (discretionary) and seven nonelective (nondiscretionary) operations and the proportions of these operations and their anesthetic procedures performed by general practitioners were calculated. Cholecystectomy increased in frequency 32% from 1968 through 1973, tonsillectomy and adenoidectomy decreased 37%, and hysterectomy increased 41%. Except for colectomy the rates for nonelective operations changed only slightly over the 6 years. Case-fatality rates (hospital deaths per 10000 operations) for the discretionary operations in 1973 were as follows: extraction of lens, 23.1; tonsillectomy and adenoidectomy, 0.4 (2 deaths among 52938 operations); varicose vein stripping, 6.1; nonrecurrent inguinal herniorrhaphy, 21.9; cholecystectomy, 61.0; hemorrhoidectomy, 9.8; prostatectomy, 115.9; and hysterectomy, 9.6. In 1973 general practitioners did 32% of tonsillectomies and adenoidectomies (61% in 1971), 10 to 20% of inguinal herniorrhaphies, hemorrhoidectomies and appendectomies and 6% or less of the other operations. However, they performed 35% or more of the anesthetic procedures for these four operations as well as for varicose vein stripping, cholecystectomy and hysterectomy. Rates of general-practice surgery and anesthesia in an urban centre in Ontario were substantially less than those for the province as a whole.

Adolescent↗
PubMedDate not supplied

Evaluation of the efficacy of pelvic shielding in preadolescent girls.

SUMMARY: A standing anteroposterior pelvic radiograph with gonadal shielding is used as a screening tool for all patients evaluated for intoeing at our institution. Sixty-two normal consecutive screening pelvic radiographs obtained in 61 female patients between the ages of 4 and 6 years were evaluated. Radiographs were evaluated for the adequacy to assess the hips as well as the protection afforded the ovaries from radiation exposure. Radiographs were judged to be inadequate because the shield covered essential landmarks in at least one hip in eight radiographs (13%). Five radiographs (8%) covered >50% of the area of both ovaries, and only one radiograph covered >75% of the area of both ovaries. Standard techniques of positioning gonadal shields in preadolescent girls are inadequate and provide minimal protection with a high rate of interference with vital landmarks. We no longer advocate using gonadal shields on initial screening radiographs of preadolescent girls.

Child↗