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Biomedical subjects

S L Lin

Publications and source records attributed to S L Lin.

At least 181 records · Page 10Linked to original sources
PubMedDate not supplied

Age-associated changes in interferon-gamma and interleukin-4 secretion by purified human CD4+ and CD8+ T cells.

Aging is associated with a decline in immune function. Interferon-gamma (IFN-gamma) and interleukin-4 (IL-4), two important immune deviation-related cytokines, are mainly produced by type 1 and type 2 T cells, respectively. To investigate the age-associated changes in the secretion of these two cytokines, 20 elderly and 20 young subjects fulfilling the SENIEUR protocol were enrolled. The ratios of CD4+ to CD8+ T cells were not different between the two age groups. The CD4+ and CD8+ T cells were purified by a magnetic cell sorting system, and then activated by concurrent anti-CD3 and anti-CD28 stimulation. The released cytokines were determined by ELISA. Both the CD4+ and the CD8+ T cells of the elderly individuals secreted a significantly larger amount of IFN-gamma after activation. Profound IL-4 production by CD8+ T cells was observed in the older subjects compared with that of the young subjects. These data suggested that age-associated decrease in immunity may be related to an imbalance in the secretion of immune deviation cytokines. The number of IL-4-secreting CD8+ T cells (T cytotoxic 2) rose significantly in the older individuals. Our design also provided a useful way to differentiate the T cell subsets secreting the same cytokine, such as IFN-gamma-producing T helper 1 and T cytotoxic 1 cells.

Adolescent↗
PubMedDate not supplied

Inaccuracy of Doppler estimates of pulmonary artery pressure using pulmonary flow acceleration time.

Pulsed Doppler echocardiography was used to estimate mean pulmonary artery pressure (PAP), mean pulmonary artery wedge pressure PAWP) and the changes in PAP and PAWP following intervention in an unselected population composed of 60 patients undergoing routine diagnostic cardiac catheterization. Simultaneous Doppler and strain gauge manometry recordings of PAP and PAWP were interpreted by independent observers in a blinded fashion. A first set of measurements was obtained before left ventricular angiography and a second soon after the injection of contrast dye. The mean Doppler PAP and PAWP were derived from acceleration time and calculated using previously published regression equations: PAP = -0.45 x AcT + 79, PAWP = 57 - 0.39 x AcT. At rest, PAP measurements by strain gauge manometry ranged from 13 to 45 mmHg with a mean of 24 +/- 10 (one standard deviation); PAWP ranged from 2 to 40 mmHg with a mean of 15 +/- 6. Following left ventricular angiography, the PAP ranged from 18 to 50 mmHg with a mean of 29 +/- 7; PAWP ranged from 6 to 45 mmHg with a mean of 20 +/- 7. The values obtained by pulsed Doppler before and after intervention correlated poorly with those obtained by strain gauge manometry (r = 0.09 and 0.26 for PAP; r = 0.03 and 0.25 for PAWP).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Detection of early myocardial tissue changes in acute canine myocardial infarction by ultrasonic tissue characterization methods.

To determine the time after left anterior descending (LAD) artery occlusion in which myocardial texture changes first occur, two-dimensional echocardiograms on five sham operated dogs and eight dogs before and after proximal LAD occlusion were performed. Serial two-dimensional echocardiograms were performed every 15 mins by placing a 5 MHz transducer directly on the chest wall. The dogs were sacrificed at the end of the study and the area of myocardial infarction was confirmed by triphenyltetrazolium chloride staining. The two-dimensional echocardiogram images were digitized. The mean pixel intensity +/- SD in the area of myocardial infarction (region of asynergy) and a normally moving area (control region) equidistant from the transducer were calculated; thus, each dog served as its own control. In sham operated dogs, no significant changes in mean pixel intensity, skewness or kurtosis were observed. There was a significant increase (P less than 0.01) in mean pixel intensity in the infarcted regions (anteroseptal) compared to values obtained in the normally moving (lateral) regions at 30 mins (mean pixel intensity 25.2 +/- 2.1 versus 23.0 +/- 0.7, P less than 0.05); this difference persisted at 45 mins (mean pixel intensity 25.8 +/- 0.9 versus 22.6 +/- 0.5, P less than 0.01), 60 mins (mean pixel intensity 27.2 +/- 1.4 versus 22.8 +/- 0.8, P less than 0.01), 90 mins (mean pixel intensity 28.6 +/- 1.6 versus 22.5 +/- 0.9, P less than 0.01) and 180 mins (mean pixel intensity 28.7 +/- 1.8 versus 21.3 +/- 1.4, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗